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Sample records for rocks wells surface

  1. Rapid transport from the surface to wells in fractured rock: a unique infiltration tracer experiment.

    Science.gov (United States)

    Levison, Jana K; Novakowski, Kent S

    2012-04-01

    A unique infiltration tracer experiment was performed whereby a fluorescent dye was applied to the land surface in an agricultural field, near Perth, Ontario, Canada, to simulate the transport of solutes to two pumped monitoring wells drilled into the granitic gneiss aquifer. This experiment, interpreted using the discrete-fracture capability of the numerical model HydroGeoSphere, showed that solute transport from the surface through thin soil (less than 2m) to wells in fractured bedrock can be extremely rapid (on the order of hours). Also, it was demonstrated that maximum concentrations of contaminants originating from the ground surface will not necessarily be the highest in the shallow aquifer horizon. These are important considerations for both private and government-owned drinking water systems that draw water from shallow fractured bedrock aquifers. This research illustrates the extreme importance of protecting drinking water at the source.

  2. Optically stimulated luminescence dating of rock surfaces

    DEFF Research Database (Denmark)

    Sohbati, Reza

    There are many examples of rock surfaces, rock art and stone structures whose ages are of great importance to the understanding of various phenomena in geology, climatology and archaeology. Optically stimulated luminescence (OSL) dating is a well-established chronological tool that has successfully...... of rock surfaces is successfully tested by application to two different quartz-rich rock types (sandstone and quartzite). Together with the measurement of infrared stimulated luminescence (IRSL) signals as a function of depth into the surface of different granites it is clear that both OSL and IRSL can....... Based on the studies of residual luminescence as a function of depth into a rock surface discussed above, a model is developed that relates this increase in residual luminescence to the exposure time. The model is then further developed using the quartz OSL signal from buried quartzite cobbles...

  3. Optically stimulated luminescence dating of rock surfaces

    DEFF Research Database (Denmark)

    Sohbati, Reza

    There are many examples of rock surfaces, rock art and stone structures whose ages are of great importance to the understanding of various phenomena in geology, climatology and archaeology. Optically stimulated luminescence (OSL) dating is a well-established chronological tool that has successfully...... determined the depositional age of a wide variety of fine-grained sediments, from several years to several hundred thousands of years. However, there is no routine OSL dating method applicable to larger clasts such as cobbles, boulders and other rock surfaces. Here the application of quartz OSL to the dating...... of rock surfaces is successfully tested by application to two different quartz-rich rock types (sandstone and quartzite). Together with the measurement of infrared stimulated luminescence (IRSL) signals as a function of depth into the surface of different granites it is clear that both OSL and IRSL can...

  4. Rock discontinuity surface roughness variation with scale

    Science.gov (United States)

    Bitenc, Maja; Kieffer, D. Scott; Khoshelham, Kourosh

    2017-04-01

    ABSTRACT: Rock discontinuity surface roughness refers to local departures of the discontinuity surface from planarity and is an important factor influencing the shear resistance. In practice, the Joint Roughness Coefficient (JRC) roughness parameter is commonly relied upon and input to a shear strength criterion such as developed by Barton and Choubey [1977]. The estimation of roughness by JRC is hindered firstly by the subjective nature of visually comparing the joint profile to the ten standard profiles. Secondly, when correlating the standard JRC values and other objective measures of roughness, the roughness idealization is limited to a 2D profile of 10 cm length. With the advance of measuring technologies that provide accurate and high resolution 3D data of surface topography on different scales, new 3D roughness parameters have been developed. A desirable parameter is one that describes rock surface geometry as well as the direction and scale dependency of roughness. In this research a 3D roughness parameter developed by Grasselli [2001] and adapted by Tatone and Grasselli [2009] is adopted. It characterizes surface topography as the cumulative distribution of local apparent inclination of asperities with respect to the shear strength (analysis) direction. Thus, the 3D roughness parameter describes the roughness amplitude and anisotropy (direction dependency), but does not capture the scale properties. In different studies the roughness scale-dependency has been attributed to data resolution or size of the surface joint (see a summary of researches in [Tatone and Grasselli, 2012]). Clearly, the lower resolution results in lower roughness. On the other hand, have the investigations of surface size effect produced conflicting results. While some studies have shown a decrease in roughness with increasing discontinuity size (negative scale effect), others have shown the existence of positive scale effects, or both positive and negative scale effects. We

  5. Fluid-Rock Characterization and Interactions in NMR Well Logging

    Energy Technology Data Exchange (ETDEWEB)

    George J. Hirasaki; Kishore K. Mohanty

    2005-09-05

    The objective of this report is to characterize the fluid properties and fluid-rock interactions that are needed for formation evaluation by NMR well logging. The advances made in the understanding of NMR fluid properties are summarized in a chapter written for an AAPG book on NMR well logging. This includes live oils, viscous oils, natural gas mixtures, and the relation between relaxation time and diffusivity. Oil based drilling fluids can have an adverse effect on NMR well logging if it alters the wettability of the formation. The effect of various surfactants on wettability and surface relaxivity are evaluated for silica sand. The relation between the relaxation time and diffusivity distinguishes the response of brine, oil, and gas in a NMR well log. A new NMR pulse sequence in the presence of a field gradient and a new inversion technique enables the T{sub 2} and diffusivity distributions to be displayed as a two-dimensional map. The objectives of pore morphology and rock characterization are to identify vug connectivity by using X-ray CT scan, and to improve NMR permeability correlation. Improved estimation of permeability from NMR response is possible by using estimated tortuosity as a parameter to interpolate between two existing permeability models.

  6. FRACTAL PROPERTIES OF ROCK FRACTURE SURFACES

    Institute of Scientific and Technical Information of China (English)

    王金安; 谢和平; MarekA.KWASNIEWSKI

    1996-01-01

    To give a better understanding of the morphological features of rock fracture surfaces within the framework of fractal geometry, the fractal characters of the rough surfaces in" rock are analyzed according to the variogram method. The study elaborates the significance of the geometric parameters-fractal dimension D and the intercept A on a log-log plot to the surface structure. Investigation extends to the anisotropy and heterogeneity of rock fracture surfaces, and the scale effect on the fractal estimation. The present study indicates that fractal dimension alone may not be sufficient to characterize the surface roughness of rock joints. A reliable estimation should take into account the combination of D and A.

  7. Generalized Models for Rock Joint Surface Shapes

    Directory of Open Access Journals (Sweden)

    Shigui Du

    2014-01-01

    Full Text Available Generalized models of joint surface shapes are the foundation for mechanism studies on the mechanical effects of rock joint surface shapes. Based on extensive field investigations of rock joint surface shapes, generalized models for three level shapes named macroscopic outline, surface undulating shape, and microcosmic roughness were established through statistical analyses of 20,078 rock joint surface profiles. The relative amplitude of profile curves was used as a borderline for the division of different level shapes. The study results show that the macroscopic outline has three basic features such as planar, arc-shaped, and stepped; the surface undulating shape has three basic features such as planar, undulating, and stepped; and the microcosmic roughness has two basic features such as smooth and rough.

  8. Rheological characteristics of soft rock structural surface

    Institute of Scientific and Technical Information of China (English)

    陈沅江; 吴超; 傅衣铭

    2008-01-01

    There are two mechanisms of the coarse surface asperity resistance effect and rubbing resistance effect in the course of the soft rock structural surface creep,of which the former plays a dominant role in hindering the deformation in the starting creep phase,so that the structural surface creep usually displays the strong surface roughness effect,and so does the latter when the asperities in the coarse surface were fractured by shearing.Under the low stress condition,there are only two phases of the decelerating creep and the constant creep for the soft rock structural surface,and as the stress increases and overcomes the rubbing resistance,the accelerating creep failure of the structural surface will happen suddenly.Therefore,a multiple rheological model,which combines the nonlinear NEWTON body(NN) of a certain mass and the empirical plastic body(EM) with the classical SAINT VENANT body,NEWTON body,KELVIN body and HOOKE body,could be used to comprehensively describe the creep characteristics of the soft rock structural surface.Its mechanical parameter values will vary owing to the different surface roughness of the structural surface.The parameters of GH,GK and ηL are positively linearly correlative to the surface roughness.The surface roughness and m are negative exponential function correlation.The long-term strength τS is positively correlative to the surface roughness.

  9. Technology for Increasing Geothermal Energy Productivity. Computer Models to Characterize the Chemical Interactions of Goethermal Fluids and Injectates with Reservoir Rocks, Wells, Surface Equiptment

    Energy Technology Data Exchange (ETDEWEB)

    Nancy Moller Weare

    2006-07-25

    This final report describes the results of a research program we carried out over a five-year (3/1999-9/2004) period with funding from a Department of Energy geothermal FDP grant (DE-FG07-99ID13745) and from other agencies. The goal of research projects in this program were to develop modeling technologies that can increase the understanding of geothermal reservoir chemistry and chemistry-related energy production processes. The ability of computer models to handle many chemical variables and complex interactions makes them an essential tool for building a fundamental understanding of a wide variety of complex geothermal resource and production chemistry. With careful choice of methodology and parameterization, research objectives were to show that chemical models can correctly simulate behavior for the ranges of fluid compositions, formation minerals, temperature and pressure associated with present and near future geothermal systems as well as for the very high PT chemistry of deep resources that is intractable with traditional experimental methods. Our research results successfully met these objectives. We demonstrated that advances in physical chemistry theory can be used to accurately describe the thermodynamics of solid-liquid-gas systems via their free energies for wide ranges of composition (X), temperature and pressure. Eight articles on this work were published in peer-reviewed journals and in conference proceedings. Four are in preparation. Our work has been presented at many workshops and conferences. We also considerably improved our interactive web site (geotherm.ucsd.edu), which was in preliminary form prior to the grant. This site, which includes several model codes treating different XPT conditions, is an effective means to transfer our technologies and is used by the geothermal community and other researchers worldwide. Our models have wide application to many energy related and other important problems (e.g., scaling prediction in petroleum

  10. Prediction of thermal conductivity of sedimentary rocks from well logs

    DEFF Research Database (Denmark)

    Fuchs, Sven; Förster, Andrea

    2014-01-01

    . A common procedure in the latter approach is the use of empirical relations between TC and different petrophysical properties. Although numerous prediction equations were developed in the past five decades, none of these seem to be universally applicable for all major types of sedimentary rocks (clastics...... combinations of standard geophysical well-logs. In combination with a feasible mixing-model (i.e. geometric mean model) bulk TC is computed along borehole profiles. The underlying approach was proposed by Fuchs & Förster (2014) and rests upon the detailed analysis of the interrelations between major physical...... parameters (i.e. thermal conductivity, density, hydrogen index, sonic interval transit time, gamma-ray response, photoelectric factor) of artificial mineral assemblages consisting 15 rock-forming minerals that are used in different combinations to typify sedimentary rocks. The predictive capacity of the new...

  11. Fluid-Rock Characterization and Interactions in NMR Well Logging

    Energy Technology Data Exchange (ETDEWEB)

    Hirasaki, George J.; Mohanty, Kishore K.

    2003-02-10

    The objective of this project was to characterize the fluid properties and fluid-rock interactions that are needed for formation evaluation by NMR well logging. The advances made in the understanding of NMR fluid properties are summarized in a chapter written for an AAPG book on NMR well logging. This includes live oils, viscous oils, natural gas mixtures, and the relation between relaxation time and diffusivity.

  12. Fluid-Rock Characterization and Interactions in NMR Well Logging

    Energy Technology Data Exchange (ETDEWEB)

    Hirasaki, George J.; Mohanty, Kishore K.

    2003-02-10

    The objective of this project was to characterize the fluid properties and fluid-rock interactions which are needed for formation evaluation by NMR well logging. NMR well logging is finding wide use in formation evaluation. The formation parameters commonly estimated were porosity, permeability, and capillary bound water. Special cases include estimation of oil viscosity, residual oil saturation, location of oil/water contact, and interpretation on whether the hydrocarbon is oil or gas.

  13. Influence of shear velocity on frictional characteristics of rock surface

    Indian Academy of Sciences (India)

    T N Singh; A K Verma; Tanmay Kumar; Avi Dutt

    2011-02-01

    Understanding the fundamental issues related with the effect of shear velocity on frictional characteristics at the interface of rock surfaces is an important issue. In this paper, strain-rate dependence on friction is investigated in relation to sliding behaviour under normal load. The phenomenon of stick-slip of granite and shaly sandstone with a tribometer at constant rate of strain under normal loads was observed. Friction at the interface of the rock samples was developed by increasing shear strain at a constant rate by applying constant velocity using the tribometer. For shaly sandstone, state parameters ( and ) played a major role in determining the friction values and roughness of the contact surfaces as well. Higher values of for shaly sandstone may be attributed to the fact that its surface had a greater number of pronounced asperities. Rubbing between the surfaces does not mean that surface becomes smoother. This is because of variation of friction between surfaces.

  14. Petrographic analysis and correlation of volcanic rocks in Bostic 1-A well near Mountain Home, Idaho

    Energy Technology Data Exchange (ETDEWEB)

    Arney, B.H.; Gardner, J.N.; Belluomini, S.G.

    1984-01-01

    Detailed examination of volcanic rock cuttings from the Bostic 1-A well near Mountain Home, Idaho, provides data that correlate the stratigraphy of the well with the regional stratigraphy of the western Snake River Plain. The Bostic 1-A well penetrates basalt of the Middle Pleistocene Bruneau Formation and underlying sedimentary rocks of the Upper Pliocene Glenns Ferry Formation. Basalt underlying the Glenns Ferry Formation is most likely Banbury Basalt of Middle Pliocene age or Banbury equivalent. A 350-ft interval of felsic volcanics is then intersected above another 600 ft of basalt. The well bottoms in altered felsic volcanics. The lowest 600 ft of basalt flows has not been correlated with any basalt observed on the surface. From the established stratigraphy of the region, and from petrographic evidence, the silicic volcanic rocks occurring both above and below the lowermost basalts in the well are probably lower Pliocene Idavada Volcanics. North of the well, in the Mt. Bennett Hills, Idavada Volcanics overlie crystalline rocks of the Idaho batholith. No estimate of depth to plutonic bedrock can be made from the well data alone. Stratigraphic comparisons suggest as little as 0.2 to 0.3 km more of Idavada lie beneath the Bostic 1-A well. Results of geophysical studies suggest additional basalt lies beneath the Bostic 1-A rather than granitic rocks of the batholith.

  15. Fluid-Rock Characterization and Interactions in NMR Well Logging

    Energy Technology Data Exchange (ETDEWEB)

    Hirasaki, George J.; Mohanty, Kishore, K.

    2001-07-13

    The objective of this project is to characterize the fluid properties and fluid-rock interactions that are needed for formation evaluation by NMR well logging. This is the first annual progress report submitted to the DOE. It reports on the work completed during the reporting period even if it may have started before this period. This project is a partnership between Professor George J. Hirasaki at Rice University and Professor Kishore Mohanty at University of Houston. In addition to the DOE, this project is supported by a consortium of oil companies and service companies. The fluid properties characterization has emphasized the departure of live oils from correlations based on dead oils. Also, asphaltic components can result in a difference between the T1 and T2 relaxation time distributions as well as reduce the hydrogen index. The fluid rock characterizations that are reported here are the effects of wettability and internal magnetic field gradients. A pore reconstruction method ha s been developed to recreate three-dimensional porous media from two-dimensional images that reproduce some of their key statistical properties. A Monte Carlo simulation technique has been developed to calculate the magnetization decay in fluid saturated porous media given their pore structure.

  16. Research on Complexity of Surface Undulating Shapes of Rock Joints

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    The surface undulating shapes of rock joints have been described qualitatively or experimental-quantitatively for a long time. The non-determined describing method can not fit quantitative evaluation of mechanical parameters of rock joints in engineering. In this paper, relative amplitude (RA) is chosen as a quantitative-describing index of surface measurement of 1 023 surface undulating curves which conducted by profile curve device(PCD). We discuss the nonuniformity,anisotropy and unhomogeneity of surface undulating shapes of joints. A new method that analyzes the complexity of surface undulating shapes of rock joints directional-statistically in various rock joints is also put forward.

  17. Fracture Detection in Geothermal Wells Drilled in Volcanic Rocks

    Energy Technology Data Exchange (ETDEWEB)

    Gonfalini, Mauro; Chelini, Walter; Cheruvier, Etienne; Suau, Jean; Klopf, Werner

    1987-01-20

    The Phlegrean Fields, close to Naples, are the site of important geothermal activity. The formations are volcanic and mostly tuffites. They are originally very tight but the geothermal alteration locally produces fractures with large increase in permeability. The lack of geological markers makes well-to-well correlation quite difficult. Thus the local detection of fractured zones in each well is very important for the evaluation of its potential. The Mofete 8 D well is a typical example. A rather complete logging program was run for fracture detection. Standard methods turned out to be disappointing. However several non-standard detectors were found to be very consistent and, later on, in excellent agreement with the analysis of cuttings. They are derived from the Dual Laterolog, the SP, the Temperature log and, most particularly, the Acoustic Waveforms from the Long Spacing Sonic. The Dual Laterolog and the Temperature Log indicate invasion by fresh and cold mud filtrate; the SP behaves as in a typical Sand-Shale sequence. Sonic Waveforms were first analyzed by a purely empirical method derived from consistent log patterns. A practical algorithm compares the total energy measured in each of the two fixed time windows located the one before, the other after the fluid arrivals. The altered zones (i.e. fractured and permeable) are clearly shown by a complete reversal of the relative energy of these two windows. A more scientific method was then applied to the Waveforms; it is based on both logging experiments and physical considerations. The energy carried by the tube wave is separated by a frequency discrimination: it correlates very well with formation alteration, thus also with the other indicators including the empirical Waveform method. It should have two advantages: – It should permit at least a semi quantitative permeability evaluation – It seems to be promising in other formations: non-volcanic geothermal wells and even hydrocarbon-bearing rocks. 10 refs

  18. Prediction of thermal conductivity of sedimentary rocks from well logs

    DEFF Research Database (Denmark)

    Fuchs, Sven; Förster, Andrea

    2014-01-01

    . A common procedure in the latter approach is the use of empirical relations between TC and different petrophysical properties. Although numerous prediction equations were developed in the past five decades, none of these seem to be universally applicable for all major types of sedimentary rocks (clastics...... parameters (i.e. thermal conductivity, density, hydrogen index, sonic interval transit time, gamma-ray response, photoelectric factor) of artificial mineral assemblages consisting 15 rock-forming minerals that are used in different combinations to typify sedimentary rocks. The predictive capacity of the new...

  19. Fluid-Rock Characterization and Interactions in NMR Well Logging

    Energy Technology Data Exchange (ETDEWEB)

    Hirasaki, George J.; Mohanty, Kishore K.

    2001-07-13

    This semi-annual report briefly summarizes the progress since the 1st Annual Report issued September, 2000 and the next annual report. More detailed results will be in the annual reports. The main emphasis on fluid properties was on measurements of the relaxation time and self-diffusion coefficient of ethane and propane. Ethane is similar to methane while propane is more similar to the higher alkanes. The ratio of T1 and T2 is demonstrated to be a function of both viscosity and the NMR frequency. The diffusion-induced T2 in a uniform magnetic gradient was simulated in one dimension to seek improved understanding NMR diffusion in restricted geometry. Analytical solutions can be found for this system if the correct region of validity is used. Estimation of permeability of vuggy carbonates has been problematic because the pore body size does not correlate well with pore throat size. CT scans and CPMG NMR measurements were made on a set of vuggy carbonate rocks.

  20. A New View of the Surface of Mars: High-Resolution Rock Abundance from MGS TES

    Science.gov (United States)

    Nowicki, S.; Christensen, P.

    2001-12-01

    Mars Global Surveyor Thermal Emission Spectrometer data from the most dust-free seasons on Mars were used to calculate the areal percentage of rocks and finer materials such as dust and sand. Rock is defined as a surface material that has a thermal inertia of 1250 J/m2-s1/2-K (30 cal/cm2-s1/2-K) or greater. A surface with a high rock abundance value could be exposed bedrock, blocky debris, well-cemented materials or a combination. Globally, the TES and IRTM data agree well, with no rocks exposed in the large dusty regions such as Tharsis and Arabia, and exposure of rocks in small (a few km) areas where likely eolian or mass-wasting processes actively remove dust from the ancient rocky surface. Analysis of high-resolution TES rock abundance suggests that there are extremely varied surfaces within relatively small regions, and places an upper limit of ~45 % rocks in the rockiest regions. Thermal inertia and rock abundance are correlate to some degree over much of the planet, but the highest thermal inertia surfaces often do not have the highest rock abundances. A global perspective will be presented here, with detailed look at a few high-resolution ares including Ares Vallis/Pathfinder, Valles Marineris, and the proposed landing sites for the 2003 MER landers.

  1. Comparisons of venus surface compositions with terrestrial ocean floor rocks

    Energy Technology Data Exchange (ETDEWEB)

    Garvin, J.B.; Bryan, W.B.

    1987-10-01

    Statistical comparison of Venera and Vega lander x-ray fluorescence spectrometer measurements of the composition of the Venus surface with an extensive database of compositional data for terrestrial ocean floor rocks indicates that the Venera 14 data matches certain tholeiitic basalts from the Kane Fracture Zone (KFZ) in the Mid-Atlantic Ridge (22-25/sup 0/N) at high confidence levels. The tholeiites most similar to the Venera measurements are very primitive, low-calcium, high-alumina pillow basalts depleted in clinopyroxene, and are relatively unique to certain fracture zones in oceanic regions. If the Venera 14 analogy is valid, the implication is that certain Venus basaltic magmas have lost clinopyroxene at relatively high pressures by fractionation, perhaps within a deep source region. Comparisons of Venera 13 and Vega 2 data with oceanic rocks yield poorer matches. Venera 13 matches Loihi seamount alkali basalts, as well as potassic mafic rocks from oceanic island such as Tristan de Cunha. The best analogy to Vega 2 may be altered gabbros or basic lavas from terrestrial basic intrusions such as the Troodos ophiolite. The close similarity of a representative sample of Venera 14 material with distinctive ocean floor tholeiitic basalts suggests that deep magma storage regions exist on Venus, and that derivation of both tholeiitic and alkalic magmas from a single primitive parent may be an important process on Venus.

  2. Geohydrology of rocks penetrated by test well USW H-6, Yucca Mountain, Nye County, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Craig, R.W. [Geological Survey, Denver, CO (United States); Reed, R.L. [Fenix and Scisson, Inc., Tulsa, OK (United States)

    1991-12-01

    Test well USW H-6 is one of several wells drilled in the Yucca Mountain area near the southwestern part of the Nevada Test Site for investigations related to isolation of high-level nuclear waste. This well was drilled to a depth of 1,220 meters. Rocks penetrated are predominantly ash-flow tuffs of Tertiary age, with the principal exception of dacitic(?) lave penetrated at a depth from 877 to 1,126 meters. The composite static water level was about 526 meters below the land surface; the hydraulic head increased slightly with depth. Most permeability in the saturated zone is in two fractured intervals in Crater Flat Tuff. Based on well-test data using the transitional part of a dual-porosity solution, an interval of about 15 meters in the middle part of the Bullfrog Member of the Crater Flat Tuff has a calculated transmissivity of about 140 meters squared per day, and an interval of about 11 meters in the middle part of the Tram Member of the Crater Flat Tuff has a calculated transmissivity of about 75 meters squared per day. The upper part of the Bullfrog Member has a transmissivity of about 20 meters squared per day. The maximum likely transmissivity of any rocks penetrated by the test well is about 480 meters squared per day, based on a recharge-boundary model. The remainder of the open hole had no detectable production. Matrix hydraulic conductivity ranges from less than 5 {times} 10{sup {minus}5} to 1 {times} 10{sup {minus}3} meter per day. Ground water is a sodium bicarbonate type that is typical of water from tuffaceous rock of southern Nevada. The apparent age of the water is about 14,6000 years. 29 refs., 26 figs., 5 tabs.

  3. Alteration of Lunar Rock Surfaces through Interaction with the Space Environment

    Science.gov (United States)

    Frushour, A. M.; Noble, S. K; Christoffersen, R.; Keller, L P.

    2014-01-01

    Space weathering occurs on all ex-posed surfaces of lunar rocks, as well as on the surfaces of smaller grains in the lunar regolith. Space weather-ing alters these exposed surfaces primarily through the action of solar wind ions and micrometeorite impact processes. On lunar rocks specifically, the alteration products produced by space weathering form surface coatings known as patina. Patinas can have spectral reflectance properties different than the underlying rock. An understanding of patina composition and thickness is therefore important for interpreting re-motely sensed data from airless solar system bodies. The purpose of this study is to try to understand the physical and chemical properties of patina by expanding the number of patinas known and characterized in the lunar rock sample collection.

  4. Investigating the resetting of OSL signals in rock surfaces

    DEFF Research Database (Denmark)

    Sohbati, Reza; Murray, Andrew S.; Jain, Mayank

    2011-01-01

    There are many examples of buried rock surfaces whose age is of interest to geologists and archaeologists. Luminescence dating is a potential method which can be applied to dating such surfaces; as part of a research project which aims to develop such an approach, the degree of resetting of OSL...... signals in grains and slices from five different cobbles/boulders collected from a modern beach is investigated. All the rock surfaces are presumed to have been exposed to daylight for a prolonged period of time (weeks to years). Feldspar was identified as the preferred dosimeter because quartz extracts...... were insensitive. Dose recovery tests using solar simulator and IR diodes on both K-feldspar grains and solid slices taken from the inner parts of the rocks are discussed. Preheat plateau results using surface grains and slices show that significant thermal transfer in naturally bleached samples can...

  5. The thermal maturation degree of organic matter from source rocks revealed by wells logs including examples from Murzuk Basin, Libya

    Energy Technology Data Exchange (ETDEWEB)

    Negoita, V.; Gheorghe, A.

    1995-08-01

    The customary technique used to know the organic matter quantity per rock volume it as well as the organic matter maturation stage is based on geochemical analyses accomplished on a preselected number of samples and cuttings drawn from boreholes during the drilling period. But the same objectives can be approached without any extra cost using the continuous measurements of well logs recorded in each well from the ground surface to the total depth. During the diagenetic stage, the identification of potential source rocks out of which no hydrocarbon have been generated may be carried out using a well logging suite including Gamma Ray Spectrometry, the Compensated Neutron/Litho Density combination and a Dual Induction/Sonic Log. During the catagenetic stage the onset of oil generation brings some important changes in the organic matter structure as well as in the fluid distribution throughout the pore space of source rocks. The replacement of electric conductive water by electric non-conductive hydrocarbons, together with water and oil being expelled from source rocks represent a process of different intensities dependent of time/temperature geohistory and kerogen type. The different generation and expulsion scenarios of hydrocarbons taking place during the catagenetic and metagenetic stages of source rocks are very well revealed by Induction and Laterolog investigations. Several crossplots relating vitrinite reflectance, total organic carbon and log-derived physical parameters are illustrated and discussed. The field applications are coming from Murzuk Basin, where Rompetrol of Libya is operating.

  6. Data Validation Package September 2016 Groundwater and Surface Water Sampling at the Slick Rock, Colorado, Processing Sites January 2017

    Energy Technology Data Exchange (ETDEWEB)

    Traub, David [Navarro Research and Engineering, Inc., Oak Ridge, TN (United States); Nguyen, Jason [US Department of Energy, Washington, DC (United States)

    2017-01-04

    The Slick Rock, Colorado, Processing Sites are referred to as the Slick Rock West Processing Site (SRK05) and the Slick Rock East Processing Site (SRK06). This annual event involved sampling both sites for a total of 16 monitoring wells and 6 surface water locations as required by the 2006 Draft Final Ground Water Compliance Action Plan for the Slick Rock, Colorado, Processing Sites (GCAP). A domestic well was also sampled at a property adjacent to the Slick Rock East site at the request of the landowner.

  7. The potentiality of hydrocarbon generation of the Jurassic source rocks in Salam-3x well,

    Directory of Open Access Journals (Sweden)

    Mohamed M. El Nady

    2016-03-01

    Full Text Available The present work deals with the identification of the potential and generating capability of oil generation in the Jurassic source rocks in the Salam-3x well. This depending on the organo-geochemical analyses of cutting samples representative of Masajid, Khatatba and Ras Qattara formations, as well as, representative extract samples of the Khatatba and Ras Qattara formations. The geochemical analysis suggested the potential source intervals within the encountered rock units as follows: Masajid Formation bears mature source rocks and have poor to fair generating capability for generating gas (type III kerogen. Khatatba Formation bears mature source rock, and has poor to good generating capability for both oil and gas. Ras Qattara Formation constituting mature source rock has good to very good generating capability for both oil and gas. The burial history modeling shows that the Masajid Formation lies within oil and gas windows; Khatatba and Ras Qattara formations lie within the gas window. From the biomarker characteristics of source rocks it appears that the extract is genetically related as the majority of them were derived from marine organic matters sources (mainly algae deposited under reducing environment and take the direction of increasing maturity and far away from the direction of biodegradation. Therefore, Masajid Formation is considered as effective source rocks for generating hydrocarbons, while Khatatba and Ras Qattara formations are the main source rocks for hydrocarbon accumulations in the Salam-3x well.

  8. 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.

  9. FEATURES OF GEODEFORMATION CHANGES OF NEAR SURFACE SEDIMENTARY ROCKS

    Directory of Open Access Journals (Sweden)

    I. A. Larionov

    2016-11-01

    Full Text Available The results of investigations of the deformation process in the near surface sedimentary rocks, which has been carried out in a seismically active region of Kamchatka peninsular since 2007,are presented. The peculiarity of the experiments on the registration of geodeformations is the application of a laser deformograph-interferometer constructed according to the Michelson interferometer scheme.

  10. Calculation of thermal conductivity, thermal diffusivity and specific heat capacity of sedimentary rocks using petrophysical well logs

    Science.gov (United States)

    Fuchs, Sven; Balling, Niels; Förster, Andrea

    2015-12-01

    In this study, equations are developed that predict for synthetic sedimentary rocks (clastics, carbonates and evapourates) thermal properties comprising thermal conductivity, specific heat capacity and thermal diffusivity. The rock groups are composed of mineral assemblages with variable contents of 15 major rock-forming minerals and porosities of 0-30 per cent. Petrophysical properties and their well-logging-tool-characteristic readings were assigned to these rock-forming minerals and to pore-filling fluids. Relationships are explored between each thermal property and other petrophysical properties (density, sonic interval transit time, hydrogen index, volume fraction of shale and photoelectric absorption index) using multivariate statistics. The application of these relations allows computing continuous borehole profiles for each rock thermal property. The uncertainties in the prediction of each property vary depending on the selected well-log combination. Best prediction is in the range of 2-8 per cent for the specific heat capacity, of 5-10 per cent for the thermal conductivity, and of 8-15 for the thermal diffusivity, respectively. Well-log derived thermal conductivity is validated by laboratory data measured on cores from deep boreholes of the Danish Basin, the North German Basin, and the Molasse Basin. Additional validation of thermal conductivity was performed by comparing predicted and measured temperature logs. The maximum deviation between these logs is effect on the subsurface temperature field can be observed in the North German Basin. This effect reduces the surface heat-flow density by 25 mW m-2.

  11. The electrical conductivity and surface conduction of consolidated rock cores.

    Science.gov (United States)

    Alkafeef, Saad F; Alajmi, Abdullah F

    2007-05-15

    A fully computerized high-pressure and high-temperature core holder device is simultaneously used to determine the electrical conductivity, zeta potential, and surface conductivity of consolidated rock cores in aqueous and nonaqueous systems. The total electrical conductivity of rock cores was determined by coupling streaming current and potential measurements. This shows that neglecting the surface conductivity Ksigma is crucial to converting the streaming potential into zeta potentials. It is observed that plots of the core total conductivity as a function of the electrolyte conductivity KL exhibit two behaviors. At low ionic strength, the core conductivity clearly depends on the contribution of surface conductivity behind the slip plane, whereas at higher ionic strength, the magnitude of the surface conductivity becomes negligible. The electrical conductivity of rock cores was found to be in good agreement with the O'Brien theory and the Briggs method. The contribution of the stagnant layer to the surface conductivity in nonaqueous systems has been shown to be significant. This shows that the stagnant layer displays significantly different behavior in different nonaqueous systems, depending on the core porosity and the double-layer overlap. The results indicate that the application of electrokinetics in petroleum reservoirs can provide important insights into reservoir fluid flow characterization.

  12. KREEP Rocks

    Institute of Scientific and Technical Information of China (English)

    邹永廖; 徐琳; 欧阳自远

    2004-01-01

    KREEP rocks with high contents of K, REE and P were first recognized in Apollo-12 samples, and it was confirmed later that there were KREEP rock fragments in all of the Apollo samples, particularly in Apollo-12 and-14 samples. The KREEP rocks distributed on the lunar surface are the very important objects of study on the evolution of the moon, as well as to evaluate the utilization prospect of REE in KREEP rocks. Based on previous studies and lunar exploration data, the authors analyzed the chemical and mineral characteristics of KREEP rocks, the abundance of Th on the lunar surface materials, the correlation between Th and REE of KREEP rocks in abundance, studied the distribution regions of KREEP rocks on the lunar surface, and further evaluated the utilization prospect of REE in KREEP rocks.

  13. Technical and cost analysis of rock-melting systems for producing geothermal wells. [GEOWELL

    Energy Technology Data Exchange (ETDEWEB)

    Altseimer, J.H.

    1976-11-01

    The drilling of wells makes up a large fraction of the costs of geothermal energy-extraction plants, and billions of dollars for wells will be needed before geothermal energy is nationally significant. Technical and economic systems studies are summarized regarding the application of the Subterrene concept, i.e., excavating and penetrating rocks or soils by melting, to the production of deep wells such as may be used for dry hot rock or geopressurized geothermal energy-extraction systems. Technically, it was found that Subterrene features are compatible with those of current rotary drilling practices. In fact, some special features could lead to improved well production techniques. These include the buildup of a glass lining along the borehole wall which provides structural resistance to collapse; close control of hole geometry; the existence of a barrier between the drilling fluids and the formations being penetrated; nonrotation; potentially better bit life; and faster rates of penetration in deep, hard rock. A typical optimum-cost well would be rotary-drilled in the upper regions and then rock-melted to total depth. Indicated cost savings are significant: a 30 percent or 3.9 million dollar (1975 $) reduction from rotary-drilled well costs are estimated for a 10-km depth well with a bottom hole temperature of 673 K. Even for relatively cool normal geothermal gradient conditions, the savings for the 1..pi..-km well are estimated as 23 percent of 2.1 million dollars.

  14. Characterization of the rock joint surface. A contribution to DECOVALEX II Task 3 `Constitutive relationships of rock joints`

    Energy Technology Data Exchange (ETDEWEB)

    Vuopio, J.; Poellae, J. [VTT Communities and Infrastructure, Espoo (Finland)

    1997-12-01

    In order to understand the effects of spent fuel on the hydraulical behaviour of the rock mass it is necessary to have knowledge about the relationship between the stresses and hydraulical properties of the fractures. The roughness of a fracture surface governs the dilatation of the fracture and the displacement of the fracture surface under shear stress. The peak shear strength and hydraulic flow properties of fractures depend very much on the surface roughness. This report describes different methods and techniques used in the characterization of rock joint surfaces and their applications in rock mechanics. 29 refs.

  15. EVALUATION OF RESERVOIR ROCK AND WELL BORE CEMENT ALTERATION WITH SUPERCRITICAL CO2

    Energy Technology Data Exchange (ETDEWEB)

    William k. O' Connor; Gilbert E Rush

    2009-01-01

    An evaluation of the alteration of reservoir rock and well bore cement at their interface, under supercritical CO{sub 2} (SCCO{sub 2}), was conducted at the laboratory-scale using simulated brine solutions at down-hole conditions. These studies were intended to identify potential leakage pathways for injected CO{sub 2} due to degradation of the well bore. Two distinct test series were conducted on core samples of the Mt. Simon sandstone from the Illinois Basin, IL, and the Grand Ronde basalt from the Pasco Basin, WA. LaFarge Class H well bore cement was used for both series. Reservoir rock/cement cores were immersed within a CO{sub 2}-saturated brine for up to 2000 hours at 35 degrees C and 100 atm CO{sub 2}. Results suggest that the impact of SCCO{sub 2} injection is reservoir-specific, being highly dependent on the reservoir brine and rock type. Brine pH can be significantly altered by CO{sub 2} injection, which in turn can dramatically impact the dissolution characteristics of the reservoir rock. Finally, well bore cement alteration was identified, particularly for fresh cast cement allowed to cure at SCCO{sub 2} conditions. However, this alteration was generally limited to an outer rind of carbonate and Ca-depleted cement which appeared to protect the majority of the cement core from further attack. These studies indicate that at the cement-rock interface, the annular space may be filled by carbonate which could act as an effective barrier against further CO{sub 2} migration along the well bore.

  16. Surface water discharges from onshore stripper wells.

    Energy Technology Data Exchange (ETDEWEB)

    Veil, J. A.

    1998-01-16

    Under current US Environmental Protection Agency (EPA) rules, small onshore oil producers are allowed to discharge produced water to surface waters with approval from state agencies; but small onshore gas producers, however, are prohibited from discharging produced water to surface waters. The purpose of this report is to identify those states that allow surface water discharges from small onshore oil operations and to summarize the types of permitting controls they use. It is intended that the findings of this report will serve as a rationale to encourage the EPA to revise its rules and to remove the prohibition on surface water discharges from small gas operations.

  17. New approaches in the indirect quantification of thermal rock properties in sedimentary basins: the well-log perspective

    DEFF Research Database (Denmark)

    Fuchs, Sven; Balling, Niels; Förster, Andrea

    capacity in sedimentary rocks derived from data provided by standard geophysical well logs. The approach is based on a data set of synthetic sedimentary rocks (clastic rocks, carbonates and evaporates) composed of mineral assemblages with variable contents of 15 major rock-forming minerals and porosities......: Fuchs, Sven; Balling, Niels; Förster, Andrea (2015): Calculation of thermal conductivity, thermal diffusivity and specific heat capacity of sedimentary rocks using petrophysical well logs. Geophysical Journal International 203, 1977-2000, doi: 10.1093/gji/ggv403...

  18. Constraining the age of rock art by dating a rockfall event using sediment and rock-surface luminescence dating techniques

    DEFF Research Database (Denmark)

    Chapot, Melissa; Sohbati, Reza; Murray, A.S.

    2012-01-01

    Optically stimulated luminescence (OSL) is used to determine the age of a rockfall event that removed part of the pictograph figures at the Great Gallery rock art panel in Canyonlands National Park, Utah, USA. Analyses from the outer millimeter of the buried surface of a rockfall boulder and quar...... rock art with a controversial and unknown origin.......Optically stimulated luminescence (OSL) is used to determine the age of a rockfall event that removed part of the pictograph figures at the Great Gallery rock art panel in Canyonlands National Park, Utah, USA. Analyses from the outer millimeter of the buried surface of a rockfall boulder and quartz...

  19. Characterization of Rock Mechanical Properties Using Lab Tests and Numerical Interpretation Model of Well Logs

    Directory of Open Access Journals (Sweden)

    Hao Xu

    2016-01-01

    Full Text Available The tight gas reservoir in the fifth member of the Xujiahe formation contains heterogeneous interlayers of sandstone and shale that are low in both porosity and permeability. Elastic characteristics of sandstone and shale are analyzed in this study based on petrophysics tests. The tests indicate that sandstone and mudstone samples have different stress-strain relationships. The rock tends to exhibit elastic-plastic deformation. The compressive strength correlates with confinement pressure and elastic modulus. The results based on thin-bed log interpretation match dynamic Young’s modulus and Poisson’s ratio predicted by theory. The compressive strength is calculated from density, elastic impedance, and clay contents. The tensile strength is calibrated using compressive strength. Shear strength is calculated with an empirical formula. Finally, log interpretation of rock mechanical properties is performed on the fifth member of the Xujiahe formation. Natural fractures in downhole cores and rock microscopic failure in the samples in the cross section demonstrate that tensile fractures were primarily observed in sandstone, and shear fractures can be observed in both mudstone and sandstone. Based on different elasticity and plasticity of different rocks, as well as the characteristics of natural fractures, a fracture propagation model was built.

  20. Igneous rocks identification on well-log data; Classificacao de rochas igneas em perfis eletricos

    Energy Technology Data Exchange (ETDEWEB)

    Souza-Lima, Wagner [PETROBRAS S.A., Salvador, BA (Brazil). Unidade de Negocio de Exploracao e Producao de Sergipe e Alagoas. Ativo de Exploracao], E-mail: wagnersl@petrobras.com.br; Pinho, Gustavo de Carvalho; Silva, Patricia Martins; Paraizo, Paulo Lopes Brandao

    2005-11-15

    An attempt to discriminate and characterise igneous rocks on well-log data is made in a well drilled on the Cabo Sub-basin (JG-1 well, Sergipe- Alagoas Basin), situated on the northeastern coast of Brazil. Log data from the twelve drilled igneous intervals were analysed on RHOBxPHIN and DTxGRxResistivity cross plots. Similar diagrams were constructed for igneous data from the 1-CPE-1-PE well, drilled on the same basin, and with igneous data from other Brazilian basins. At the RHOBxPHIN cross plot, twelve lithologic fields were discriminated, and their characteristics verified against petrographic data. Two trends are perceptible: the basic rocks set (olivine-basalt, andesite, basaltic pumice and basaltic andesite) distributed along the dolomite line, and the acid rocks set (trachyandesite/quartz-latite, trachyandesite, trachyte, olivine-trachyandesite and acid pumice) coincident with the calcite line. At the DTxGRxResistivity cross plot, the basic set occurs around low-GR field, and the acid set is distributed around high-GR field. The JG-1 well's log data were submitted to discriminant analysis, and the results were checked against the CPE-1 well's curves, for validation. For the first well, the hits ranged from 82 and 100%. For the second well, a perfect lithologic identification was obtained, except for those cases where the lithotypes does not exist in the JG-1 well. One of the main applications for this technique is the stratigraphic correlation for the volcanic successions from sedimentary basins, mainly in the absence of good biostratigraphic markers. (author)

  1. Quantitative Estimates of Bio-Remodeling on Coastal Rock Surfaces

    Directory of Open Access Journals (Sweden)

    Marta Pappalardo

    2016-05-01

    Full Text Available Remodeling of rocky coasts and erosion rates have been widely studied in past years, but not all the involved processes acting over rocks surface have been quantitatively evaluated yet. The first goal of this paper is to revise the different methodologies employed in the quantification of the effect of biotic agents on rocks exposed to coastal morphologic agents, comparing their efficiency. Secondly, we focus on geological methods to assess and quantify bio-remodeling, presenting some case studies in an area of the Mediterranean Sea in which different geological methods, inspired from the revised literature, have been tested in order to provide a quantitative assessment of the effects some biological covers exert over rocky platforms in tidal and supra-tidal environments. In particular, different experimental designs based on Schmidt hammer test results have been applied in order to estimate rock hardness related to different orders of littoral platforms and the bio-erosive/bio-protective role of Chthamalus ssp. and Verrucariaadriatica. All data collected have been analyzed using statistical tests to evaluate the significance of the measures and methodologies. The effectiveness of this approach is analyzed, and its limits are highlighted. In order to overcome the latter, a strategy combining geological and experimental–computational approaches is proposed, potentially capable of revealing novel clues on bio-erosion dynamics. An experimental-computational proposal, to assess the indirect effects of the biofilm coverage of rocky shores, is presented in this paper, focusing on the shear forces exerted during hydration-dehydration cycles. The results of computational modeling can be compared to experimental evidence, from nanoscopic to macroscopic scales.

  2. Improving the groundwater-well siting approach in consolidated rock in Nampula Province, Mozambique

    Science.gov (United States)

    Chirindja, F. J.; Dahlin, T.; Juizo, D.

    2017-08-01

    Vertical electrical sounding was used for assessing the suitability of the drill sites in crystalline areas within a water supply project in Nampula Province in Mozambique. Many boreholes have insufficient yield (ohm-m) with disintegrated rock fragments characterized by intermediate porosity and permeability, and the fractured zone (>420 ohm-m) with low porosity and high permeability. In addition to this, there is unfractured nonpermeable intact rock with resistivity of thousands of ohm-m. The unsuccessful boreholes were drilled over a highly resistive zone corresponding to fresh crystalline rock and a narrow altered layer with lower resistivity. Successful boreholes were drilled in places where the upper layers with lower resistivity correspond to a well-developed altered layer or a well-fractured basement. There are a few exceptions with boreholes drilled in seemingly favourable locations but they were nevertheless unsuccessful boreholes for unknown reasons. Furthermore, there were boreholes drilled into very resistive zones that produced successful water wells, which may be due to narrow permeable fracture zones that are not resolved by ERT. Community involvement is proposed, in choosing between alternative borehole locations based on information acquired with a scientifically based approach, including conceptual geological models and ERT. This approach could probably lower the borehole failure rate.

  3. New approaches in the indirect quantification of thermal rock properties in sedimentary basins: the well-log perspective

    DEFF Research Database (Denmark)

    Fuchs, Sven; Balling, Niels; Förster, Andrea

    Numerical temperature models generated for geodynamic studies as well as for geothermal energy solutions heavily depend on rock thermal properties. Best practice for the determination of those parameters is the measurement of rock samples in the laboratory. Given the necessity to enlarge databases...... capacity in sedimentary rocks derived from data provided by standard geophysical well logs. The approach is based on a data set of synthetic sedimentary rocks (clastic rocks, carbonates and evaporates) composed of mineral assemblages with variable contents of 15 major rock-forming minerals and porosities......, hydrogen index, volume fraction of shale and photoelectric absorption index) on a regression sub set of data (70% of data) (Fuchs et al., 2015). Prediction quality was quantified on the remaining test sub set (30% of data). The combination of three to five well-log parameters results in predictions...

  4. Measurements and predictions of surface gas fluxes and actual evaporation on mine waste rock dump

    Energy Technology Data Exchange (ETDEWEB)

    Kabwe, L.K.; Wilson, G.W. [British Columbia Univ., Vancouver, BC (Canada). Dept. of Mining and Mineral Process Engineering

    2006-07-01

    Long-term closure issues with respect to the mining industry and acid rock drainage (ARD) management require accurate measurements, predictions and monitoring of surface gas fluxes and actual evaporation on mine waste-rock dumps. This study uses a technique, called the dynamic closed chamber system (DCC) that measures the oxygen flux into mine waste dumps. The technique was used with an oxygen gas analyzer to directly measure the change in the oxygen concentration in the headspace of the chamber installed at the surface of the waste dumps. A SoilCover model was also used to predict evaporation fluxes on a waste-rock pile after heavy rainfall events. Measurement of actual evaporation across the surfaces of waste dumps is important in the design of soil covers. The paper discussed the site locations including the Key Lake uranium mine located at the southern rim of the Athabasca Basin in north central Saskatchewan as well as the Syncrude Canada Ltd. mine, located 30 km north of Fort McMurray, Alberta. Materials and methods used in the study as well as results and subsequent discussion were also presented. The effect of relative humidity and the effect of soil cover system on oxygen diffusion was reviewed. It was concluded that the SoilCover numerical model can be a useful tool for prediction of actual evaporation on mine waste dumps. 21 refs., 4 figs.

  5. New approaches in the indirect quantification of thermal rock properties in sedimentary basins: the well-log perspective

    Science.gov (United States)

    Fuchs, Sven; Balling, Niels; Förster, Andrea

    2016-04-01

    Numerical temperature models generated for geodynamic studies as well as for geothermal energy solutions heavily depend on rock thermal properties. Best practice for the determination of those parameters is the measurement of rock samples in the laboratory. Given the necessity to enlarge databases of subsurface rock parameters beyond drill core measurements an approach for the indirect determination of these parameters is developed, for rocks as well a for geological formations. We present new and universally applicable prediction equations for thermal conductivity, thermal diffusivity and specific heat capacity in sedimentary rocks derived from data provided by standard geophysical well logs. The approach is based on a data set of synthetic sedimentary rocks (clastic rocks, carbonates and evaporates) composed of mineral assemblages with variable contents of 15 major rock-forming minerals and porosities varying between 0 and 30%. Petrophysical properties are assigned to both the rock-forming minerals and the pore-filling fluids. Using multivariate statistics, relationships then were explored between each thermal property and well-logged petrophysical parameters (density, sonic interval transit time, hydrogen index, volume fraction of shale and photoelectric absorption index) on a regression sub set of data (70% of data) (Fuchs et al., 2015). Prediction quality was quantified on the remaining test sub set (30% of data). The combination of three to five well-log parameters results in predictions on the order of Journal International 203, 1977-2000, doi: 10.1093/gji/ggv403

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

    Science.gov (United States)

    Uxa, Tomáš; Mida, Peter

    2017-04-01

    mean annual air temperature (MAAT), which averaged +2.3 ˚ C in both years (estimated from nearby Lomnický štít station using a lapse rate of 6.5 ˚ C/km). Accordingly, GSTs showed negative surface offset (MAGST-MAAT) of -1.3 ˚ C and -1.5 ˚ C in 2014-2015 and 2015-2016, respectively. At the coldest sites, the surface offset regularly reached values well below -2 ˚ C and dropped up to -3.3 ˚ C. GSTs recorded prior to the onset of snow melting (i.e. BTS) averaged -3.8 ˚ C and -3.2 ˚ C in spring of 2015 and 2016, respectively, and varied between -5.8 ˚ C and -1.6 ˚ C. One-time BTS values showed the average of -2.8 ˚ C, but relatively high short-distance heterogeneity of BTS values, ranging between -8.3 ˚ C and 0.0 ˚ C, was encountered across the rock-glacier surfaces. The results suggest that permafrost occurrence is probable or possible in a total of ten rock glaciers, while its absence is probable only in one of the investigated landforms. We classify the latter form as relict and other two rock glaciers are suggested to be in inactive/relict state. Six rock glaciers are believed to be inactive and two even active/inactive. In most cases, however, permafrost likely occurs in a form of isolated patches or discontinuously and presumably degrades under present climate conditions.

  7. Fault zone properties in carbonate rocks: insights for well logs, core and field data

    Science.gov (United States)

    Giorgioni, Maurizio; Cilona, Antonino; Tondi, Emanuele; Agosta, Fabrizio

    2010-05-01

    In the last few years, numerous works addressed the deformation processes in carbonate rocks. These studies, generally sponsored by the oil industry, aimed to a better understanding of the structural and hydraulic properties of fault zones as well as of the subsurface fluid pathways in deformed carbonate rocks. This effort was mainly driven by the economic significance that carbonate rocks have for the oil industry, since they represent important natural reservoirs of hydrocarbons. According to the many field-based research scientific articles published in the recent past, both structural and hydraulic properties of fault zones, and their evolution trough time, exert a first order control on subsurface fluid flow and accumulation in fractured carbonate reservoirs. In order to convert this knowledge into predictive modeling tools that would help to optimize their exploitation, it should be useful to integrate the field-based data together with the subsurface data, which generally consist of core and well log (resistivity, acoustic, gamma ray etc.) analyses usually gathered to assess the formation evaluation of carbonate reservoir. The presented work aims at filling this cognitive gap by the acquisition and elaboration of subsurface geophysical properties of a hydrocarbon-bearing oblique normal fault zone characterized by 10's of m offset, and cropping out in an exposed analogue of fractured carbonate reservoir (Maiella Mountain, Italy). The deformation mechanisms associated to the processes of fault nucleation and development within the Oligo-Miocene shallow-water carbonate rocks were documented in the recent past by our research group. In this present contribution, we present the results of our elaboration of the geophysical data, obtained from well logs oriented perpendicular to the study fault zone. These results are consistent with the following statements: a) there is a meaningful correlations between cores and digital images; b) a detailed structural analysis

  8. Induced polarization of volcanic rocks. 1Surface versus quadrature conductivity

    Science.gov (United States)

    Revil, A.; Breton, M. Le; Niu, Q.; Wallin, E.; Haskins, E.; Thomas, D. M.

    2016-11-01

    We performed complex conductivity measurements on 28 core samples from the hole drilled for the Humu´ula Groundwater Research Project (Hawai´i Island, HI, USA). The complex conductivity measurements were performed at 4 different pore water conductivities (0.07, 0.5, 1.0 or 2.0, and 10 S m-1 prepared with NaCl) over the frequency range 1 mHz to 45 kHz at 22 ± 1°C. The in-phase conductivity data are plotted against the pore water conductivity to determine, sample by sample, the intrinsic formation factor and the surface conductivity. The intrinsic formation factor is related to porosity by Archie's law with an average value of the cementation exponent m of 2.45, indicating that only a small fraction of the connected pore space controls the transport properties. Both the surface and quadrature conductivities are found to be linearly related to the cation exchange capacity of the material, which was measured with the cobalt hexamine chloride method. Surface and quadrature conductivities are found to be proportional to each other like for sedimentary siliclastic rocks. A Stern layer polarization model is used to explain these experimental results. Despite the fact that the samples contain some magnetite (up to 5% wt.), we were not able to identify the effect of this mineral on the complex conductivity spectra. These results are very encouraging in showing that galvanometric induced polarization measurements can be used in volcanic areas to separate the bulk from the surface conductivity and therefore to define some alteration attributes. Such a goal cannot be achieved with resistivity alone.

  9. Induced polarization of volcanic rocks - 1. Surface versus quadrature conductivity

    Science.gov (United States)

    Revil, A.; Le Breton, M.; Niu, Q.; Wallin, E.; Haskins, E.; Thomas, D. M.

    2017-02-01

    We performed complex conductivity measurements on 28 core samples from the hole drilled for the Humu'ula Groundwater Research Project (Hawai'i Island, HI, USA). The complex conductivity measurements were performed at 4 different pore water conductivities (0.07, 0.5, 1.0 or 2.0, and 10 S m-1 prepared with NaCl) over the frequency range 1 mHz to 45 kHz at 22 ± 1 °C. The in-phase conductivity data are plotted against the pore water conductivity to determine, sample by sample, the intrinsic formation factor and the surface conductivity. The intrinsic formation factor is related to porosity by Archie's law with an average value of the cementation exponent m of 2.45, indicating that only a small fraction of the connected pore space controls the transport properties. Both the surface and quadrature conductivities are found to be linearly related to the cation exchange capacity of the material, which was measured with the cobalt hexamine chloride method. Surface and quadrature conductivities are found to be proportional to each other like for sedimentary siliclastic rocks. A Stern layer polarization model is used to explain these experimental results. Despite the fact that the samples contain some magnetite (up to 5 per cent wt.), we were not able to identify the effect of this mineral on the complex conductivity spectra. These results are very encouraging in showing that galvanometric induced polarization measurements can be used in volcanic areas to separate the bulk from the surface conductivity and therefore to define some alteration attributes. Such a goal cannot be achieved with resistivity alone.

  10. Seismoacoustic emission and electromagnetic radiation of fractured rocks in deep wells

    Science.gov (United States)

    Troyanov, A. K.; D'Yakonov, B. P.; Martyshko, P. S.; Astrakhantsev, Yu. G.; Nachapkin, N. I.; Gavrilov, V. A.; Beloglazova, N. A.

    2011-01-01

    The results of simultaneous measurements in seismoacoustic emission (SAE) and electromagnetic radiation (EMR), carried out with the help of a program-apparatus complex developed at the Institute of Geophysics, Ural Division, Russian Academy of Sciences, are considered. Measurements have been carried out in the wells with varied structures located in Karelia, Yamal-Nenets Autonomous Area, and Kamchatka. It has been shown that intervals of fractured rocks are simultaneously recorded in anomalies of SAE and EMR signals. This fact allows us to detect these zones of high tensosensitivity in a geomedium volume for the purposes of monitoring in geodynamic phenomena in the Earth's crust.

  11. Survival times of meter-sized rock boulders on the surface of airless bodies

    Science.gov (United States)

    Basilevsky, A. T.; Head, J. W.; Horz, F.; Ramsley, K.

    2015-11-01

    granulometrically fine material on the surface of small asteroids does not prove the predominance of thermal stresses over rupture by meteorite impacts as a factor in the comminution of the surface material. We then analyzed images of lunar rocks of decimeters- to meters-size whose lunar surface exposure ages were radiometrically dated. This analysis shows that the presence of the fragment on the lunar surface for a time period 26-400 Ma (that is, ~3×108 to 5×109 day-night thermal cycles) did not lead to the formation of any features conclusively supporting rock destruction by thermal cycles. In turn, this means that on the lunar surface as well as on the surface of other bodies at 1 AU and further from the Sun, the destruction of rocks by thermal fatigue is secondary compared to rock rupture by the meteorite impacts. The possible implications of the difference in environments on fast spinning asteroids and on the Moon require additional analysis Then utilizing the entire catalog of inner solar system minor planet orbits out to Jupiter as a proxy for the distribution of potential impactors throughout the inner solar system, we calculated the meteorite flux and impact velocities for a number of airless bodies to use them for estimates of survival times of rock boulders on their surfaces (normalized to those for lunar boulders). We found that if the average survival time for meter-size rock boulders on the surface of the Moon is 1, then considering rupture by the meteorite impacts as the major process of rock destruction, for Phobos it is ~0.8, for Deimos ~0.7, for asteroid Itokawa ~1, for Eros ~0.3, for Vesta and Ceres ~0.03 and for the average of the first 150 Trojans discovered is ~12.5. Implications of these findings are that on the surfaces of Vesta and Ceres, compared to the Moon, the regolith layer should generally have a larger thickness and higher maturity, while small craters with rocky ejecta are rare. On the typical Trojans, where impact flux is closer to that on the

  12. A Bounding Surface Plasticity Model for Intact Rock Exhibiting Size-Dependent Behaviour

    Science.gov (United States)

    Masoumi, Hossein; Douglas, Kurt J.; Russell, Adrian R.

    2016-01-01

    A new constitutive model for intact rock is presented recognising that rock strength, stiffness and stress-strain behaviour are affected by the size of the rock being subjected to loading. The model is formulated using bounding surface plasticity theory. It is validated against a new and extensive set of unconfined compression and triaxial compression test results for Gosford sandstone. The samples tested had diameters ranging from 19 to 145 mm and length-to-diameter ratios of 2. The model captures the continuous nonlinear stress-strain behaviour from initial loading, through peak strength to large shear strains, including transition from brittle to ductile behaviour. The size dependency was accounted for through a unified size effect law applied to the unconfined compressive strength—a key model input parameter. The unconfined compressive strength increases with sample size before peaking and then decreasing with further increasing sample size. Inside the constitutive model two hardening laws act simultaneously, each driven by plastic shear strains. The elasticity is stress level dependent. Simple linear loading and bounding surfaces are adopted, defined using the Mohr-Coulomb criterion, along with a non-associated flow rule. The model simulates well the stress-strain behaviour of Gosford sandstone at confining pressures ranging from 0 to 30 MPa for the variety of sample sizes considered.

  13. Physical and chemical weathering. [of Martian surface and rocks

    Science.gov (United States)

    Gooding, James L.; Arvidson, Raymond E.; Zolotov, Mikhail IU.

    1992-01-01

    Physical and chemical weathering processes that might be important on Mars are reviewed, and the limited observations, including relevant Viking results and laboratory simulations, are summarized. Physical weathering may have included rock splitting through growth of ice, salt or secondary silicate crystals in voids. Chemical weathering probably involved reactions of minerals with water, oxygen, and carbon dioxide, although predicted products vary sensitively with the abundance and physical form postulated for the water. On the basis of kinetics data for hydration of rock glass on earth, the fate of weathering-rind formation on glass-bearing Martian volcanic rocks is tentatively estimated to have been on the order of 0.1 to 4.5 cm/Gyr; lower rates would be expected for crystalline rocks.

  14. Model of Reflection Spectra of Rock Surface in 2π Space

    Institute of Scientific and Technical Information of China (English)

    ZHAO Hongying; ZHAO Hu; YAN Lei; ZHAO Yunsheng

    2004-01-01

    This paper deals with reflection spectra and polarized reflection spectra of 20 sorts of rock in 2π space, and then creates a model of reflection spectra of rock surface in 2π space. We measured the change of reflection and polarized reflection spectra as altering the incidence angle, vertex angle, azimuth angle, band and polarization. The results show that influence of the incidence angle on spectral curves is very strong. And when the vertex angle is constant, the horizontal azimuth polarizes rock spectra, and distorts the circular spectrum to become elliptic. The polarization influences the reflection intensity of rock spectra, but has no evident influence on the characteristics of wave forms of rock in 2π space. Therefore, we can describe the whole reflection spectral characteristics, including polarization,of rock surface in 2π space by measuring and calculating the e and p values in several key directions.

  15. A NEW HIGH RESOLUTION OPTICAL METHOD FOR OBTAINING THE TOPOGRAPHY OF FRACTURE SURFACES IN ROCKS

    Directory of Open Access Journals (Sweden)

    Steven Ogilvie

    2011-05-01

    Full Text Available Surface roughness plays a major role in the movement of fluids through fracture systems. Fracture surface profiling is necessary to tune the properties of numerical fractures required in fluid flow modelling to those of real rock fractures. This is achieved using a variety of (i mechanical and (ii optical techniques. Stylus profilometry is a popularly used mechanical method and can measure surface heights with high precision, but only gives a good horizontal resolution in one direction on the fracture plane. This method is also expensive and simultaneous coverage of the surface is not possible. Here, we describe the development of an optical method which images cast copies of rough rock fractures using in-house developed hardware and image analysis software (OptiProf™ that incorporates image improvement and noise suppression features. This technique images at high resolutions, 15-200 μm for imaged areas of 10 × 7.5 mm and 100 × 133 mm, respectively and a similar vertical resolution (15 μm for a maximum topography of 4 mm. It uses in-house developed hardware and image analysis (OptiProf™ software and is cheap and non-destructive, providing continuous coverage of the fracture surface. The fracture models are covered with dye and fluid thicknesses above the rough surfaces converted into topographies using the Lambert-Beer Law. The dye is calibrated using 2 devices with accurately known thickness; (i a polycarbonate tile with wells of different depths and (ii a wedge-shaped vial made from silica glass. The data from each of the two surfaces can be combined to provide an aperture map of the fracture for the scenario where the surfaces touch at a single point or any greater mean aperture. The topography and aperture maps are used to provide data for the generation of synthetic fractures, tuned to the original fracture and used in numerical flow modelling.

  16. Pore Scale Heterogeneity in the Mineral Distribution, Surface Area and Adsorption in Porous Rocks

    Science.gov (United States)

    Lai, P. E. P.; Krevor, S. C.

    2014-12-01

    The impact of heterogeneity in chemical transport and reaction is not understood in continuum (Darcy/Fickian) models of reactive transport. This is manifested in well-known problems such as scale dependent dispersion and discrepancies in reaction rate observations made at laboratory and field scales [1]. Additionally, this is a source of uncertainty for carbon dioxide injection, which produces a reactive fluid-rock system particularly in carbonate rock reservoirs. A potential cause is the inability of the continuum approach to incorporate the impact of heterogeneity in pore-scale reaction rates. This results in part from pore-scale heterogeneities in surface area of reactive minerals [2, 3]. We use x-ray micro tomography to describe the non-normal 3-dimensional distribution of reactive surface area within a porous medium according to distinct mineral groups. Using in-house image processing techniques, thin sections, nitrogen BET surface area, backscattered electron imaging and energy dispersive spectroscopy, we compare the surface area of each mineral phase to those obtained from x-ray CT imagery. In all samples, there is little correlation between the reactive surface area fraction and the volumetric fraction of a mineral in a bulk rock. Berea sandstone was far less heterogeneous and has a characteristic pore size at which a surface area distribution may be used to quantify heterogeneity. In carbonates, heterogeneity is more complex and surface area must be characterized at multiple length scales for an accurate description of reactive transport. We combine the mineral specific surface area characterisation to dynamic tomography, imaging the flow of water and solutes, to observe flow dependent and mineral specific adsorption. The observations may contribute to the incorporation of experimentally based statistical descriptions of pore scale heterogeneity in reactive transport into upscaled models, moving it closer to predictive capabilities for field scale

  17. Trajectories and energy transfer of saltating particles onto rock surfaces : application to abrasion and ventifact formation on Earth and Mars

    Science.gov (United States)

    Bridges, Nathan T.; Phoreman, James; White, Bruce R.; Greeley, Ronald; Eddlemon, Eric E.; Wilson, Gregory R.; Meyer, Christine J.

    2005-01-01

    The interaction between saltating sand grains and rock surfaces is assessed to gauge relative abrasion potential as a function of rock shape, wind speed, grain size, and planetary environment. Many kinetic energy height profiles for impacts exhibit a distinctive increase, or kink, a few centimeters above the surface, consistent with previous field, wind tunnel, and theoretical investigations. The height of the kink observed in natural and wind tunnel settings is greater than predictions by a factor of 2 or more, probably because of enhanced bouncing off hard ground surfaces. Rebounded grains increase the effective flux and relative kinetic energy for intermediate slope angles. Whether abrasion occurs, as opposed to simple grain impact with little or no mass lost from the rock, depends on whether the grain kinetic energy (EG) exceeds a critical value (EC), as well as the flux of grains with energies above EC. The magnitude of abrasion and the shape change of the rock over time depends on this flux and the value of EG > EC. Considering the potential range of particle sizes and wind speeds, the predicted kinetic energies of saltating sand hitting rocks overlap on Earth and Mars. However, when limited to the most likely grain sizes and threshold conditions, our results agree with previous work and show that kinetic energies are about an order of magnitude greater on Mars.

  18. Changes in porosity, permeability and surface area during rock dissolution: effects of mineralogical heterogeneity

    CERN Document Server

    Min, Ting; Chen, Li; Kang, Qinjun; Tao, Wen-Quan

    2015-01-01

    Effects of heterogeneity of mineral distribution and reaction rate on the rock dissolution process are investigated using a pore-scale reactive transport model based on the lattice Boltzmann method. Coupled fluid flow, species transport, chemical reaction and solid structure alternation due to dissolution are simulated. Effects of mineral distributions and chemical heterogeneity on the dissolution behaviors and evolutions of hydrologic properties are studied under different reactive transport conditions. Simulation results show that the coupling between advection, diffusion and reaction as well as the mineralogical heterogeneity leads to complex reactive transport behaviors and complicated temporal evolutions of hydrologic properties including porosity, permeability and reactive surface. Diverse relationships between surface area and volume are predicted, which cannot be described by simple models such as the spherical-grain model. Porosity-permeability relationships also differ under different mineral distri...

  19. Diminishing friction of joint surfaces as initiating factor for destabilising permafrost rocks?

    Science.gov (United States)

    Funk, Daniel; Krautblatter, Michael

    2010-05-01

    Degrading alpine permafrost due to changing climate conditions causes instabilities in steep rock slopes. Due to a lack in process understanding, the hazard is still difficult to asses in terms of its timing, location, magnitude and frequency. Current research is focused on ice within joints which is considered to be the key-factor. Monitoring of permafrost-induced rock failure comprises monitoring of temperature and moisture in rock-joints. The effect of low temperatures on the strength of intact rock and its mechanical relevance for shear strength has not been considered yet. But this effect is signifcant since compressive and tensile strength is reduced by up to 50% and more when rock thaws (Mellor, 1973). We hypotheisze, that the thawing of permafrost in rocks reduces the shear strength of joints by facilitating the shearing/damaging of asperities due to the drop of the compressive/tensile strength of rock. We think, that decreasing surface friction, a neglected factor in stability analysis, is crucial for the onset of destabilisation of permafrost rocks. A potential rock slide within the permafrost zone in the Wetterstein Mountains (Zugspitze, Germany) is the basis for the data we use for the empirical joint model of Barton (1973) to estimate the peak shear strength of the shear plane. Parameters are the JRC (joint roughness coefficient), the JCS (joint compressive strength) and the residual friction angle (φr). The surface roughness is measured in the field with a profile gauge to create 2D-profiles of joint surfaces. Samples of rock were taken to the laboratory to measure compressive strength using a high-impact Schmidt-Hammer under air-dry, saturated and frozen conditions on weathered and unweathered surfaces. Plugs where cut out of the rock and sand blasted for shear tests under frozen and unfrozen conditions. Peak shear strength of frozen and unfrozen rocks will be calculated using Barton's model. First results show a mean decrease of compressive

  20. Site Release Reports for C-Well Pipeline, UE-25 Large Rocks Test Site, and 29 GSF Test Pits

    Energy Technology Data Exchange (ETDEWEB)

    K.E. Rasmuson

    2002-04-02

    The U.S. Department of Energy has implemented a program to reclaim lands disturbed by site characterization at Yucca Mountain. Long term goals of the program are to re-establish processes on disturbed sites that will lead to self-sustaining plant communities. The Biological Opinion for Yucca Mountain Site Characterization Studies required that the U.S. Department of Energy develop a Reclamation Standards and Monitoring Plan to evaluate the success of reclamation efforts. According to the Reclamation Standards and Monitoring Plan, reclaimed sites will be monitored periodically, remediated if necessary, and eventually compared to an appropriate reference area to determine whether reclamation goals have been achieved and the site can be released from further monitoring. Plant cover, density, and species richness (success parameters) on reclaimed sites are compared to 60 percent of the values (success criteria) for the same parameters on the reference area. Small sites (less than 0.1 ha) are evaluated for release using qualitative methods while large sites (greater than 0.1 ha) are evaluated using quantitative methods. In the summer of 2000, 31 small sites reclaimed in 1993 and 1994 were evaluated for reclamation success and potential release from further monitoring. Plant density, cover, and species richness were estimated on the C-Well Pipeline, UE-25 Large Rocks test site, and 29 ground surface facility test pits. Evidence of erosion, reproduction and natural recruitment, exotic species abundance, and animal use (key attributes) also were recorded for each site and used in success evaluations. The C-Well Pipeline and ground surface facility test pits were located in a ''Larrea tridentata - Ephedra nevadensis'' vegetation association while the UE-25 Large Rocks test site was located in an area dominated by ''Coleogyne ramosissima and Ephedra nevadensis''. Reference areas in the same vegetation associations with similar slope

  1. Sedimentary petrology of oil well rock cores; Petrologia sedimentaria de nucleos de rocas de pozos petroleros

    Energy Technology Data Exchange (ETDEWEB)

    Izquierdo M, Georgina; Paredes S, Adriana [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2001-07-01

    At the request of PEMEX Exploration and Production (PEP), in the area of Geology of the Gerencia de Geotermia, the necessary methodology has been integrated to carry out the geologic characterization of cores obtained during the oil well drilling. The integrated studies have been of utility for PEMEX, because they provide detailed information on the processes, conditions of deposition and diagenesis that occur in sedimentary rocks. On the other hand, this geologic information contributes to the update of the geologic model of the field in study. [Spanish] A solicitud de PEMEX Exploracion y Produccion (PEP), en el area de Geologia de la Gerencia de Geotermia, se ha integrado la metodologia necesaria para llevar a cabo la caracterizacion geologica de nucleos obtenidos durante la perforacion de pozos petroleros. Los estudios integrados han sido de utilidad para PEMEX, pues proporcionan informacion detallada sobre los procesos, condiciones de depositacion y diagenesis que ocurren en rocas sedimentarias. Por otro lado, esta informacion geologica contribuye a la actualizacion del modelo geologico del campo en estudio.

  2. Comparison of Rock Varnish Bacterial Communities with Surrounding Non-Varnished Rock Surfaces: Taxon-Specific Analysis and Morphological Description.

    Science.gov (United States)

    Esposito, Alfonso; Ahmed, Engy; Ciccazzo, Sonia; Sikorski, Johannes; Overmann, Jörg; Holmström, Sara J M; Brusetti, Lorenzo

    2015-10-01

    Rock varnish is a thin layer of Fe and Mn oxyhydroxides with embedded clay minerals that contain an increased Mn/Fe ratio compared to that of the Earth's crust. Even if the study of rock varnish has important implications in several fields, the composition of epilithic bacterial communities and the distribution of taxa on varnish surfaces are still not wholly described. The aim of this study was (i) to identify the bacterial taxa which show the greatest variation between varnish and non-varnish environments, collected from the same rock, and (ii) to describe the morphology of epilithic communities through scanning electron microscopy (SEM). Triplicate samples of rock surfaces with varnish and triplicate samples without varnish were collected from five sites in Matsch Valley (South Tyrol, Italy). The V4 region of 16S rRNA gene was analyzed by Illumina sequencing. Fifty-five ubiquitous taxa have been examined to assess variation between varnish and non-varnish. Cyanobacteria, Chloroflexi, Proteobacteria along with minor taxa such as Solirubrobacterales, Conexibaxter, and Rhodopila showed significant variations of abundance, diversity, or both responding to the ecology (presence/absence of varnish). Other taxa, such as the genus Edaphobacter, showed a more marked spatial variation responding to the sampling site. SEM images showed a multitude of bacterial morphologies and structures involved in the process of attachment and creation of a suitable environment for growth. The features emerging from this analysis suggest that the highly oxidative Fe and Mn-rich varnish environment favors anoxigenic autotrophy and establishment of highly specialized bacteria.

  3. On the dual nature of lichen-induced rock surface weathering in contrasting micro-environments.

    Science.gov (United States)

    Marques, Joana; Gonçalves, João; Oliveira, Cláudia; Favero-Longo, Sergio E; Paz-Bermúdez, Graciela; Almeida, Rubim; Prieto, Beatriz

    2016-10-01

    Contradictory evidence from biogeomorphological studies has increased the debate on the extent of lichen contribution to differential rock surface weathering in both natural and cultural settings. This study, undertaken in Côa Valley Archaeological Park, aimed at evaluating the effect of rock surface orientation on the weathering ability of dominant lichens. Hyphal penetration and oxalate formation at the lichen-rock interface were evaluated as proxies of physical and chemical weathering, respectively. A new protocol of pixel-based supervised image classification for the analysis of periodic acid-Schiff stained cross-sections of colonized schist revealed that hyphal spread of individual species was not influenced by surface orientation. However, hyphal spread was significantly higher in species dominant on northwest facing surfaces. An apparently opposite effect was noticed in terms of calcium oxalate accumulation at the lichen-rock interface; it was detected by Raman spectroscopy and complementary X-ray microdiffraction on southeast facing surfaces only. These results suggest that lichen-induced physical weathering may be most severe on northwest facing surfaces by means of an indirect effect of surface orientation on species abundance, and thus dependent on the species, whereas lichen-induced chemical weathering is apparently higher on southeast facing surfaces and dependent on micro-environmental conditions, giving only weak support to the hypothesis that lichens are responsible for the currently observed pattern of rock-art distribution in Côa Valley. Assumptions about the drivers of open-air rock-art distribution patterns elsewhere should also consider the micro-environmental controls of lichen-induced weathering, to avoid biased measures of lichen contribution to rock-art deterioration.

  4. Characteristics of surface plasmon coupled quantum well infrared photodetectors

    Science.gov (United States)

    Hsu, Wei-Cheng; Ling, Hong-Shi; Wang, Shiang-Yu; Lee, Chien-Ping

    2017-06-01

    Quantum Well Infrared Photodetectors (QWIPs) with different structures were characterized for the study of surface plasmon wave coupling. Detailed comparisons between surface plasmon coupled and etched grating coupled devices were investigated. A bias dependence for the enhancement of the responsivity of surface plasmon coupled devices was found, especially for the samples with non-uniform quantum wells. The non-uniform QWIPs with surface plasmon coupling showed an asymmetric enhancement with respect to the bias directions. Stronger enhancements were shown under the biases when a higher effective electric field region is close to the collector. The change of the photocarrier escape probability due to the narrow coupling bandwidth of the surface plasmon wave is attributed to this unexpected bias dependence.

  5. Rock-Eval pyrolysis and vitrinite reflectance results from the Sheep Creek 1 well, Susitna basin, south-central Alaska

    Science.gov (United States)

    Stanley, Richard G.; Lillis, Paul G.; Pawlewicz, Mark J.; Haeussler, Peter J.

    2014-01-01

    We used Rock-Eval pyrolysis and vitrinite reflectance to examine the petroleum source potential of rock samples from the Sheep Creek 1 well in the Susitna basin of south-central Alaska. The results show that Miocene nonmarine coal, carbonaceous shale, and mudstone are potential sources of hydrocarbons and are thermally immature with respect to the oil window. In the samples that we studied, coals are more organic-rich and more oil-prone than carbonaceous shales and silty mudstones, which appear to be potential sources of natural gas. Lithologically similar rocks may be present in the deeper parts of the subsurface Susitna basin located west of the Sheep Creek 1 well, where they may have been buried deeply enough to generate oil and (or) gas. The Susitna basin is sparsely drilled and mostly unexplored, and no commercial production of hydrocarbons has been obtained. However, the existence of potential source rocks of oil and gas, as shown by our Rock-Eval results, suggests that undiscovered petroleum accumulations may be present in the Susitna basin.

  6. Evaporation from Near-Drift Fractured Rock Surfaces

    Science.gov (United States)

    Manepally, C.; Fedors, R. W.; Or, D.; Das, K.

    2007-12-01

    The amount of water entering emplacement drifts from a fractured unsaturated rock is an important variable for performance evaluation of a potential high-level radioactive waste repository at Yucca Mountain, Nevada. Water entering the drifts as liquid or gas may enhance waste package corrosion rates and transport released radionuclides. Liquid water in form of droplets may emerge from fractures, or flow along the drift wall and potentially evaporate and condense at other locations. Driven by pressure and temperature gradients, vapor may be transported along fractures, or liquid water may evaporate directly from the matrix. Within the drift, heat-driven convection may redistribute the moisture leading to condensation at other locations. The geometry of the evaporation front around the drift is not fully understood and this, in turn, influences processes related to reflux, rewetting as the thermal pulse dissipates. Existing models focus on processes in the porous media (e.g., two-phase dual-permeability models for matrix and fractures), or on processes in the drift (e.g., gas-phase computational fluid dynamics models). This study focuses on the boundary between these two domains, and the corresponding models, where evaporation at the solid rock/drift air interface appears to play an important role. Studies have shown that evaporation from porous media is a complex process sensitive to factors such as (i) hydrological properties of the porous media, (ii) pressure gradients in the porous media, (iii) texture of the interface or boundary, (iv) local vapor and temperature gradients, and (v) convective flow rate and boundary layer transfer. Experimental observations based on passive monitoring at Yucca Mountain have shown that the formation surrounding the drift is able to provide and transport large amounts of water vapor over a relatively short period. This study will examine the basic processes that govern evaporation in the unsaturated rock surrounding drifts for

  7. Mathematical model quantifies multiple daylight exposure and burial events for rock surfaces using luminescence dating

    DEFF Research Database (Denmark)

    Freiesleben, Trine Holm; Sohbati, Reza; Murray, Andrew

    2015-01-01

    Interest in the optically stimulated luminescence (OSL) dating of rock surfaces has increased significantly over the last few years, as the potential of the method has been explored. It has been realized that luminescence-depth profiles show qualitative evidence for multiple daylight exposure and...... to determine the length of a fossil exposure, using a known natural light exposure as calibration. © 2015 Published by Elsevier Ltd....... of the cobble and by fitting the new model to the luminescence profile, it is concluded that the cobble was well bleached before burial. This indicates that the OSL burial age is likely to be reliable. In addition, a recent known exposure event provides an approximate calibration for older daylight exposure...

  8. Geochemical, isotopic, and dissolved gas characteristics of groundwater in a fractured crystalline-rock aquifer, Savage Municipal Well Superfund site, Milford, New Hampshire, 2011

    Science.gov (United States)

    Harte, Philip T.

    2013-01-01

    Tetrachloroethylene (PCE), a volatile organic compound, was detected in groundwater from deep (more than (>) 300 feet (ft) below land surface) fractures in monitoring wells tapping a crystalline-rock aquifer beneath operable unit 1 (OU1) of the Savage Municipal Well Superfund site (Weston, Inc., 2010). Operable units define remedial areas of contaminant concern. PCE contamination within the fractured-rock aquifer has been designated as a separate operable unit, operable unit 3 (OU3; Weston, Inc., 2010). PCE contamination was previously detected in the overlying glacial sand and gravel deposits and basal till, hereafter termed the Milford-Souhegan glacial-drift (MSGD) aquifer (Harte, 2004, 2006). Operable units 1 and 2 encompass areas within the MSGD aquifer, whereas the extent of the underlying OU3 has yet to be defined. The primary original source of contamination has been identified as a former manufacturing facility—the OK Tool manufacturing facility; hence OU1 sometimes has been referred to as the OK Tool Source Area (New Hampshire Department of Environmental Services, undated). A residential neighborhood of 30 to 40 houses is located in close proximity (one-quarter of a mile) from the PCE-contaminated monitoring wells. Each house has its own water-supply well installed in similar rocks as those of the monitoring wells, as indicated by the New Hampshire State geologic map (Lyons and others, 1997). An investigation was initiated in 2010 by the U.S. Environmental Protection Agency (USEPA) region 1, and the New Hampshire Department of Environmental Services (NHDES) to assess the potential for PCE transport from known contaminant locations (monitoring wells) to the residential wells. The U.S. Geological Survey (USGS) and the NHDES entered into a cooperative agreement in 2011 to assist in the evaluation of PCE transport in the fractured-rock aquifer. Periodic sampling over the last decade by the USEPA and NHDES has yet to detect PCE in groundwater from the

  9. Effect of rock fragment embedding on the aeolian deposition of dust on stone-covered surfaces

    NARCIS (Netherlands)

    Goossens, D.

    2005-01-01

    Many stone-covered surfaces on Earth are subject to aeolian deposition of atmospheric dust. This study investigates how the deposition of dust is affected when rock fragments become gradually more embedded in the ground or, inversely, become more concentrated on the surface. Experiments were execute

  10. Numerical Simulation of Abandoned Gob Methane Drainage through Surface Vertical Wells.

    Science.gov (United States)

    Qin, Wei; Xu, Jialin; Hu, Guozhong

    2015-01-01

    The influence of the ventilation system on the abandoned gob weakens, so the gas seepage characteristics in the abandoned gob are significantly different from those in a normal mining gob. In connection with this, this study physically simulated the movement of overlying rock strata. A spatial distribution function for gob permeability was derived. A numerical model using FLUENT for abandoned gob methane drainage through surface wells was established, and the derived spatial distribution function for gob permeability was imported into the numerical model. The control range of surface wells, flow patterns and distribution rules for static pressure in the abandoned gob under different well locations were determined using the calculated results from the numerical model.

  11. Alteration of immature sedimentary rocks on Earth and Mars. Recording Aqueous and Surface-atmosphere Processes

    Energy Technology Data Exchange (ETDEWEB)

    Cannon, Kenneth M. [Brown Univ., Providence, RI (United States); Mustard, John F. [Brown Univ., Providence, RI (United States); Salvatore, Mark R. [Arizona State Univ., Mesa, AZ (United States)

    2015-03-05

    The rock alteration and rind formation in analog environments like Antarctica may provide clues to rock alteration and therefore paleoclimates on Mars. Clastic sedimentary rocks derived from basaltic sources have been studied in situ by martian rovers and are likely abundant on the surface of Mars. Moreover, how such rock types undergo alteration when exposed to different environmental conditions is poorly understood compared with alteration of intact basaltic flows. Here we characterize alteration in the chemically immature Carapace Sandstone from Antarctica, a terrestrial analog for martian sedimentary rocks. We employ a variety of measurements similar to those used on previous and current Mars missions. Laboratory techniques included bulk chemistry, powder X-ray diffraction (XRD), hyperspectral imaging and X-ray absorption spectroscopy. Through these methods we find that primary basaltic material in the Carapace Sandstone is pervasively altered to hydrated clay minerals and palagonite as a result of water–rock interaction. A thick orange rind is forming in current Antarctic conditions, superimposing this previous aqueous alteration signature. The rind exhibits a higher reflectance at visible-near infrared wavelengths than the rock interior, with an enhanced ferric absorption edge likely due to an increase in Fe3+ of existing phases or the formation of minor iron (oxy)hydroxides. This alteration sequence in the Carapace Sandstone results from decreased water–rock interaction over time, and weathering in a cold, dry environment, mimicking a similar transition early in martian history. This transition may be recorded in sedimentary rocks on Mars through a similar superimposition mechanism, capturing past climate changes at the hand sample scale. These results also suggest that basalt-derived sediments could have sourced significant volumes of hydrated minerals on early Mars due to their greater permeability compared with intact igneous rocks.

  12. Reliable yields of public water-supply wells in the fractured-rock aquifers of central Maryland, USA

    Science.gov (United States)

    Hammond, Patrick A.

    2017-07-01

    Most studies of fractured-rock aquifers are about analytical models used for evaluating aquifer tests or numerical methods for describing groundwater flow, but there have been few investigations on how to estimate the reliable long-term drought yields of individual hard-rock wells. During the drought period of 1998 to 2002, many municipal water suppliers in the Piedmont/Blue Ridge areas of central Maryland (USA) had to institute water restrictions due to declining well yields. Previous estimates of the yields of those wells were commonly based on extrapolating drawdowns, measured during short-term single-well hydraulic pumping tests, to the first primary water-bearing fracture in a well. The extrapolations were often made from pseudo-equilibrium phases, frequently resulting in substantially over-estimated well yields. The methods developed in the present study to predict yields consist of extrapolating drawdown data from infinite acting radial flow periods or by fitting type curves of other conceptual models to the data, using diagnostic plots, inverse analysis and derivative analysis. Available drawdowns were determined by the positions of transition zones in crystalline rocks or thin-bedded consolidated sandstone/limestone layers (reservoir rocks). Aquifer dewatering effects were detected by type-curve matching of step-test data or by breaks in the drawdown curves constructed from hydraulic tests. Operational data were then used to confirm the predicted yields and compared to regional groundwater levels to determine seasonal variations in well yields. Such well yield estimates are needed by hydrogeologists and water engineers for the engineering design of water systems, but should be verified by the collection of long-term monitoring data.

  13. 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.

  14. A Model for Formation of Dust, Soil and Rock Coatings on Mars: Physical and Chemical Processes on the Martian Surface

    Science.gov (United States)

    Bishop, Janice; Murchie, Scott L.; Pieters, Carle M.; Zent, Aaron P.

    2001-01-01

    This model is one of many possible scenarios to explain the generation of the current surface material on Mars using chemical, magnetic and spectroscopic data From Mars and geologic analogs from terrestrial sites. One basic premise of this model is that the dust/soil units are not derived exclusively from local rocks, but are rather a product of global, and possibly remote, weathering processes. Another assumption in this model is that there are physical and chemical interactions of the atmospheric dust particles and that these two processes create distinctly different results on the surface. Physical processes distribute dust particles on rocks and drift units, forming physically-aggregated layers; these are reversible processes. Chemical reactions of the dust/soil particles create alteration rinds on rock surfaces and cohesive, crusted surface units between rocks, both of which are relatively permanent materials. According to this model the dominant components of the dust/soil particles are derived from alteration of volcanic ash and tephra, and contain primarily nanophase and poorly crystalline ferric oxides/oxyhydroxide phases as well as silicates. These phases are the alteration products that formed in a low moisture environment. These dust/soil particles also contain a smaller amount of material that was exposed to more water and contains crystalline ferric oxides/oxyhydroxides, sulfates and clay silicates. These components could have formed through hydrothermal alteration at steam vents or fumeroles, thermal fluids, or through evaporite deposits. Wet/dry cycling experiments are presented here on mixtures containing poorly crystalline and crystalline ferric oxides/oxyhydroxides, sulfates and silicates that range in size from nanophase to 1-2 pm diameter particles. Cemented products of these soil mixtures are formed in these experiments and variation in the surface texture was observed for samples containing smectites, non-hydrated silicates or sulfates

  15. Calculation of thermal conductivity, thermal diffusivity and specific heat capacity of sedimentary rocks using petrophysical well logs

    DEFF Research Database (Denmark)

    Fuchs, Sven; Balling, Niels; Förster, Andrea

    2015-01-01

    of 15 major rock-forming minerals and porosities of 0–30 per cent. Petrophysical properties and their well-logging-tool-characteristic readings were assigned to these rock-forming minerals and to pore-filling fluids. Relationships are explored between each thermal property and other petrophysical...... of each property vary depending on the selected well-log combination. Best prediction is in the range of 2–8 per cent for the specific heat capacity, of 5–10 per cent for the thermal conductivity, and of 8–15 for the thermal diffusivity, respectively. Well-log derived thermal conductivity is validated...... by laboratory data measured on cores from deep boreholes of the Danish Basin, the North German Basin, and the Molasse Basin. Additional validation of thermal conductivity was performed by comparing predicted and measured temperature logs. The maximum deviation between these logs is

  16. Regional characterization of hydraulic properties of rock using well test data

    Energy Technology Data Exchange (ETDEWEB)

    Wladis, D.; Joensson, P.; Wallroth, T. [Chalmers Univ. of Technology., Goeteborg (Sweden). Dept. of Geology

    1997-11-01

    This study was aimed at investigating the possible use of data from the SGU well archive for characterization of the hydraulic properties of the crystalline basement of Sweden at a regional scale. Two areas studied as possible candidates for a radioactive waste repository were selected. The SGU well data and the hydraulic conductivity data evaluated from packer tests in boreholes at the sites were characterized statistically also considering possible spatial dependence. The two types of data were compared and the correlation between the data sets was investigated. This part of the study considered the uppermost 100 m of the packer test data, which is the approximate depth range covered by the SGU data. In a second part of the work the packer test data from the two study areas were analyzed in terms of possible depth trends. The exploratory statistical analyses suggested that the SGU data are useful for estimations of hydrogeological parameters for areas of different geologic settings. The geostatistical analysis provided further understanding of the spatial behaviour of the studied parameters. The analysis of depth dependence indicates that at both sites there is a layer of higher hydraulic conductivity close to the surface. Within these layers, about 200 and 280 m thick, resp., the conductivity decreases with increasing depth. At larger depths however, the decrease with depth is very slow or negligible. It was found that the scatter in the measured hydraulic conductivity data is very large compared to differences between the depth functions tested 33 refs, 21 figs, 6 tabs

  17. Dynamics of electron in a surface quantum well

    Institute of Scientific and Technical Information of China (English)

    Wang Li-Fei; Yang Guang-Can

    2009-01-01

    This paper studies the quantum dynamics of electrons in a surface quantum well in the time domain with autocorrelation of wave packet. The evolution of the wave packet for different manifold eigenstates with finite and infinite lifetimes is investigated analytically. It is found that the quantum coherence and evolution of the surface electronic wave packet can be controlled by the laser central energy and electric field. The results show that the finite lifetime of excited states expedites the dephasing of the coherent electronic wave packet significantly. The correspondence between classical and quantum mechanics is shown explicitly in the system.

  18. Survival Times of Meter-Sized Rock Boulders on the Surface of Airless Bodies

    Science.gov (United States)

    Basilevsky, A. T.; Head, J. W.; Horz, F.; Ramsley, K.

    2015-01-01

    This study considers the survival times of meter-sized rock boulders on the surfaces of several airless bodies. As the starting point, we employ estimates of the survival times of such boulders on the surface of the Moon by[1], then discuss the role of destruction due to day-night temperature cycling, consider the meteorite bombardment environment on the considered bodies in terms of projectile flux and velocities and finally estimate the survival times. Survival times of meter-sized rocks on lunar surface: The survival times of hand specimen-sized rocks exposed to the lunar surface environment were estimated based on experiments modeling the destruction of rocks by meteorite impacts, combined with measurements of the lunar surface meteorite flux, (e.g.,[2]). For estimations of the survival times of meter-sized lunar boulders, [1] suggested a different approach based on analysis of the spatial density of boulders on the rims of small lunar craters of known absolute age. It was found that for a few million years, only a small fraction of the boulders ejected by cratering process are destroyed, for several tens of million years approx.50% are destroyed, and for 200-300 Ma, 90 to 99% are destroyed. Following [2] and other works, [1] considered that the rocks are mostly destroyed by meteorite impacts. Destruction of rocks by thermal-stress. However, high diurnal temperature variations on the surface of the Moon and other airless bodies imply that thermal stresses may also be a cause of surface rock destruction. Delbo et al. [3] interpreted the observed presence of fine debris on the surface of small asteroids as due to thermal surface cycling. They stated that because of the very low gravity on the surface of these bodies, ejecta from meteorite impacts should leave the body, so formation there of fine debris has to be due to thermal cycling. Based on experiments on heating-cooling of cm-scale pieces of ordinary and carbonaceous chondrites and theoretical modeling of

  19. Well-Posedness of a fully coupled thermo-chemo-poroelastic system with applications to petroleum rock mechanics

    OpenAIRE

    Tetyana Malysheva; White, Luther W.

    2017-01-01

    We consider a system of fully coupled parabolic and elliptic equations constituting the general model of chemical thermo-poroelasticity for a fluid-saturated porous media. The main result of this paper is the developed well-posedness theory for the corresponding initial-boundary problem arising from petroleum rock mechanics applications. Using the proposed pseudo-decoupling method, we establish, subject to some natural assumptions imposed on matrices of diffusion coeff...

  20. Effect on the Performance of Drilling Fluids at Downhole Rock Surfaces at Low Temperatures

    Institute of Scientific and Technical Information of China (English)

    Mingming Zheng; Guosheng Jiang; Tianle Liu; Fulong Ning; Ling Zhang; V F Chikhotkin

    2016-01-01

    To maintain gas hydrate stability, low-temperature drilling fluids and high drilling speeds should be used while drilling in gas hydrate-bearing sediments. The effect of the drilling fluid on downhole rock surfaces at low temperatures is very important to increase the drilling rate. This paper analyzed the action mechanism of the drilling fluid on downhole rock surfaces and established a corresponding evaluation method. The softening effect of six simulated drilling fluids with 0.1 wt.% of four common surfactants and two common organic salts on the downhole rock surface strength was evaluated experimentally using the established method at low temperature. The experimental results showed that the surfactants and organic salts used in the drilling fluids aided in the reduction of the strength of the downhole rock surface, and the established evaluation method was able to quantitatively reveal the difference in the softening effect of the different drilling fluids through comparison with water. In particular, the most common surfactant that is used in drilling fluids, sodium dodecyl sulfate (SDS), had a very good softening effect while drilling under low-temperature conditions, which can be widely applied during drilling in low-temperature formations, such as natural gas hydrate-bearing sediments, the deep seafloor and permafrost.

  1. Pore-Scale Heterogeneity in the Mineral Distribution and Reactive Surface Area of Porous Rocks

    Science.gov (United States)

    Lai, P. E. P.; Krevor, S. C.

    2015-12-01

    The reactive surface area is an important control on interfacial processes between minerals and aqueous fluids in porous rocks. Spatial heterogeneity in the surface area can lead to complications in modelling reactive transport processes, but quantitative characterisation of this property has been limited. In this paper 3D images obtained using x-ray micro-tomography were used to characterise heterogeneity in surface area in one sandstone and five carbonate rocks. Measurements of average surface area from x-ray imagery were 1-2 orders of magnitude lower than measurements from nitrogen BET. A roughness factor, defined as the ratio of BET surface area to x-ray based surface area, was correlated to the presence of clay or microporosity. Coregistered images of Berea sandstone from x-ray and energy dispersive spectroscopy imagery were used to guide the identification of quartz, K-feldspar, dolomite, calcite and clays in x-ray images. In Berea sandstone, clay and K-feldspar had higher average surface area fractions than their volumetric fractions in the rock. In the Edwards carbonate, however, modal mineral composition correlated with surface area. By sub-sampling digital images, statistical distributions of the surface area were generated at various length scales of subsampling. Comparing these to distributions used in published modelling studies showed that the common practice of leaving surface area and pore volume uncorrelated in a pore leads to unrealistic combinations of surface area and pore volume in the models. We suggest these models adopt a moderate correlation based on observations. In Berea sandstone, constraining ratios of surface area to pore volume to a range of values between that of quartz-lined and five times that of clay-lined spheres appeared sufficient.

  2. Rock salt mass in the Paleoproterozoic sequence of the Onega trough in Karelia (from the Onega parametric well data)

    Science.gov (United States)

    Morozov, A. F.; Khakhaev, B. N.; Petrov, O. V.; Gorbachev, V. I.; Tarkhanov, G. V.; Tsvetkov, L. D.; Erinchek, Yu. M.; Akhmedov, A. M.; Krupenik, V. A.; Sveshnikova, K. Yu.

    2010-11-01

    A thick (200 m) rock salt mass covering Late Archean granitoids was exposed for the first time in the Early Proterozoic volcanogenic-sedimentary formations in the Onega trough of the east Baltic Shield by the Onega parametric well. The mineral composition of salts, their geochemical features, and the isotopic composition of carbonate carbon and oxygen have been studied. After fluid inclusions present in salts, their metamorphism temperature and isotopic composition of helium and argon were determined. The obtained results give evidence of the fact that rock salts and magnesites associated with them were formed in an evaporate basin with participation of deep crustal processes. The age of the underlying granitoids (2.716 ± 9 Ma) is determined using the Pb—Pb method.

  3. Acidic Microenvironments in Waste Rock Characterized by Neutral Drainage: Bacteria–Mineral Interactions at Sulfide Surfaces

    Directory of Open Access Journals (Sweden)

    John W. Dockrey

    2014-03-01

    Full Text Available Microbial populations and microbe-mineral interactions were examined in waste rock characterized by neutral rock drainage (NRD. Samples of three primary sulfide-bearing waste rock types (i.e., marble-hornfels, intrusive, exoskarn were collected from field-scale experiments at the Antamina Cu–Zn–Mo mine, Peru. Microbial communities within all samples were dominated by neutrophilic thiosulfate oxidizing bacteria. However, acidophilic iron and sulfur oxidizers were present within intrusive waste rock characterized by bulk circumneutral pH drainage. The extensive development of microbially colonized porous Fe(III (oxyhydroxide and Fe(III (oxyhydroxysulfate precipitates was observed at sulfide-mineral surfaces during examination by field emission-scanning electron microscopy-energy dispersive X-ray spectroscopy (FE-SEM-EDS. Linear combination fitting of bulk extended X-ray absorption fine structure (EXAFS spectra for these precipitates indicated they were composed of schwertmannite [Fe8O8(OH6–4.5(SO41–1.75], lepidocrocite [γ-FeO(OH] and K-jarosite [KFe3(OH6(SO42]. The presence of schwertmannite and K-jarosite is indicative of the development of localized acidic microenvironments at sulfide-mineral surfaces. Extensive bacterial colonization of this porous layer and pitting of underlying sulfide-mineral surfaces suggests that acidic microenvironments can play an important role in sulfide-mineral oxidation under bulk circumneutral pH conditions. These findings have important implications for water quality management in NRD settings.

  4. 3D Identification and Stability Analysis of Key Surface Blocks of Rock Slope

    Institute of Scientific and Technical Information of China (English)

    李明超; 周四宝; 王刚

    2016-01-01

    Complicated geological structures make it difficult to analyze the stability of rock slopes, such as faults, weak intercalated layers or joint fissures. Based on 3D geological modeling and surface block identifying methods, an integrated methodology framework was proposed and realized to analyze the stability of surface blocks in rock slopes. The surface blocks cut by geological structures, fissures or free faces could be identified subjected to the four principles of closure, completeness, uniqueness and validity. The factor of safety(FOS)of single key block was calculated by the limit equilibrium method. If there were two or more connected blocks, they were defined as a block-group. The FOS of a block-group was computed by the Sarma method. The proposed approach was applied to an actual rock slope of a hydropower project, and some possible instable blocks were demonstrated and analyzed visually. The obtained results on the key blocks or block-groups provide essential information for determining po-tential instable region of rock slopes and designing effective support scheme in advance.

  5. Application of nanoscale zero-valent iron tracer to delineate groundwater flow paths between a screened well and an open well in fractured rock

    Science.gov (United States)

    Chuang, P. Y.; Chiu, Y.; Liou, Y. H.; Teng, M. H.; Chia, Y.

    2016-12-01

    Fracture flow is of importance for water resources as well as the investigation of contaminant pathways. In this study, a novel characterization approach of nanoscale zero-valent iron (nZVI) tracer test was developed to accurately identify the connecting fracture zones of preferential flow between a screened well and an open well. Iron nanoparticles are magnetic and can be attracted by a magnet. This feature make it possible to design a magnet array for attracting nZVI particles at the tracer inlet to characterize the location of incoming tracer in the observation well. This novel approach was tested at two experiment wells with well hydraulic connectivity in a hydrogeological research station in central Taiwan. A heat-pulse flowmeter can be used to detect changes in flow velocity for delineating permeable fracture zones in the borehole and providing the design basis for the tracer test. Then, the most permeable zone in the injection well was hydraulically isolated by well screen to prevent the injected nZVI particles from being stagnated at the hole bottom. Afterwards, another hydraulic test was implemented to re-examine the hydraulic connectivity between the two wells. When nZVI slurry was injected in the injection well, they migrated through connected permeable fractures to the observation well. A breakthrough curve, observed by the fluid conductivity sensor in the observation well, indicated the arrival of nZVI slurry. The iron nanoparticles attracted to the magnets in the observation well provide the position of tracer inlet, which corroborates well with the depth of a permeable zone delineated by the flowmeter. This article demonstrates the potential of nano-iron tracer test to provide the quantitative information of fracture flow paths in fractured rock.

  6. Micro-topography, rock surface modelling and minerology of notches in Mount Carmel

    Science.gov (United States)

    Brook, Anna; Ben-Binyamin, Atzmon; Shtober-Zisu, Nurit

    2016-04-01

    Notches are defined as horizontal concaved indentations developed on slopes or cliffs in a basic "C" shape regardless of their location or formation process. Many studies have proclaimed that notches are associated with coastal processes where rocky shore faces are back carved, parallel to sea level by a combination of physical and biological abrasion, and by chemical and biological dissolution. The notches morphologies are various and depend on the lithology, climate, and environment history. These changes involve complex volumetric effects such as weathering and surface mineral dissolution. The main impetus for the present paper is to advance the modeling and the 3D complex pattern reconstruction of notch's cavity surface and detailed shapes and to assess the association between the morphological structures observed upon the notch parts and the fine scale mineralogical composition of the rock. The reconstruction of 3D surfaces using point clouds scanned data is a known problem in computer graphics. Several approaches are based on combinatorial structures, such as Delaunay triangulations, alpha shapes, or Voronoi diagrams. These schemes typically create a triangle mesh that interpolates all or most of the points. In the presence of noisy data, resulting surface is often jagged, and is therefore smoothed or refit to the points in subsequent processing. Fast Fourier Transform (FFT) is a common technique for solving dense, periodic Poisson systems. However, the FFT requires longer time and larger space, quickly becoming prohibitive for fine resolutions. The Poisson approach's key element is the observation that inward normal field of the boundary can be inferred as the gradient of a three dimensional solid indicator function. Thus, the generation of a watertight mesh can be obtained by: (1) transforming the oriented point samples into a continuous vector field referred to as the relationship between the gradient of the indicator function and an integral of surface

  7. Automatic extraction of discontinuity orientation from rock mass surface 3D point cloud

    Science.gov (United States)

    Chen, Jianqin; Zhu, Hehua; Li, Xiaojun

    2016-10-01

    This paper presents a new method for extracting discontinuity orientation automatically from rock mass surface 3D point cloud. The proposed method consists of four steps: (1) automatic grouping of discontinuity sets using an improved K-means clustering method, (2) discontinuity segmentation and optimization, (3) discontinuity plane fitting using Random Sample Consensus (RANSAC) method, and (4) coordinate transformation of discontinuity plane. The method is first validated by the point cloud of a small piece of a rock slope acquired by photogrammetry. The extracted discontinuity orientations are compared with measured ones in the field. Then it is applied to a publicly available LiDAR data of a road cut rock slope at Rockbench repository. The extracted discontinuity orientations are compared with the method proposed by Riquelme et al. (2014). The results show that the presented method is reliable and of high accuracy, and can meet the engineering needs.

  8. Surface photovoltage spectroscopy of quantum wells and superlattices

    Energy Technology Data Exchange (ETDEWEB)

    Bachrach-Ashkenasy, N.; Kronik, L.; Shapira, Y. [Department of Physical Electronics, Faculty of Engineering, Tel-Aviv University, Ramat-Aviv 69978 (Israel); Rosenwaks, Y.; Hanna, M.C. [National Renewable Energy Laboratory, Golden, Colorado 80401 (United States); Leibovitch, M.; Ram, P. [Physics Department, Brooklyn College of the City University of New York, Brooklyn, New York 11210 (United States)

    1996-02-01

    Surface photovoltage spectroscopy (SPS) has been employed to monitor optical transitions in quantum well and superlattice structures at room temperature. Excellent agreement is found between theoretical predictions of heavy hole and electron energy level positions and the observed transitions. The results show that using this technique, the complete band diagram of the quantum structure may be constructed. SPS emerges as a powerful tool capable of monitoring optical transitions above the lowest one in a simple to interpret, contactless, and nondestructive way. {copyright} {ital 1996 American Institute of Physics.}

  9. Matrix diffusion in crystalline rocks: coupling of anion exclusion, surface diffusion and surface complexation

    Energy Technology Data Exchange (ETDEWEB)

    Olin, M.; Valkiainen, M.; Aalto, H. [VTT Chemical Technology, Espoo (Finland)

    1997-12-01

    This report includes both experimental and modelling parts. Also, a novel approach to the diffusion experiments is introduced, where ions of the same electric charge diffuse in opposite directions through the same rock sample. Six rock-types from Olkiluoto radioactive waste disposal investigation site were used in the experiments: granite, weathered granite, mica gneiss, weathered mica gneiss, tonalite and altered mica gneiss/migmatite. The experiments consisted of the determination of the effective diffusion coefficient and the rock capacity factor for tritium, chloride (Cl-36) and sodium (Na-22). The modelling consisted of a chemical model for small pores (< 100 nm), a model for counter ion diffusion and models for the laboratory experiments. 21 refs.

  10. Surface water supply for the Clearlake, California Hot Dry Rock Geothermal Project

    Energy Technology Data Exchange (ETDEWEB)

    Jager, A.R.

    1996-03-01

    It is proposed to construct a demonstration Hot Dry Rock (HDR) geothermal plant in the vicinity of the City of Clearlake. An interim evaluation has been made of the availability of surface water to supply the plant. The evaluation has required consideration of the likely water consumption of such a plant. It has also required consideration of population, land, and water uses in the drainage basins adjacent to Clear Lake, where the HDR demonstration project is likely to be located. Five sources were identified that appear to be able to supply water of suitable quality in adequate quantity for initial filling of the reservoir, and on a continuing basis, as makeup for water losses during operation. Those sources are California Cities Water Company, a municipal supplier to the City of Clearlake; Clear Lake, controlled by Yolo County Flood Control and Water Conservation District; Borax Lake, controlled by a local developer; Southeast Regional Wastewater Treatment Plant, controlled by Lake County; and wells, ponds, and streams on private land. The evaluation involved the water uses, water rights, stream flows, precipitation, evaporation, a water balance, and water quality. In spite of California`s prolonged drought, the interim conclusion is that adequate water is available at a reasonable cost to supply the proposed HDR demonstration project.

  11. Tectonic subsidence modelling and Gondwana source rock hydrocarbon potential, Northwest Bangladesh modelling of Kuchma, Singra and Hazipur wells

    Energy Technology Data Exchange (ETDEWEB)

    Frielingsdorf, J. [Shell Petroleum Development Company, Nigeria Limited, P.O. Box 23, Port Harcourt, Rivers State (Nigeria); Aminul Islam, Sk.; Mizanur Rahman, Md. [BAPEX, Bangladesh Petroleum Exploration and Production Ltd., Shahjalal Tower, 80/A-B Siddeshwari Circular Road, Dhaka 1217 (Bangladesh); Block, Martin [Federal Institute for Geosciences and Natural Resources (BGR), Stilleweg 2, 30655 Hannover (Germany); Golam Rabbani, Md. [Norwegian University of Science and Technology (NTNU), 7491 Trondheim (Norway)

    2008-06-15

    The northwestern part of Bangladesh is in terms of hydrocarbon exploration still under-explored. This paper presents the basin development from a structural point of view and includes the results of thermal and maturity modelling using numerical tools of basin modelling. One regional seismic section and three exploration wells have been investigated to unravel a conceptual model for the subsidence and thermal history of the region. According to the findings it is very likely that up to 2900 m of Triassic/Jurassic and partly Permian sediments have been eroded prior to the break-up of Gondwana. During continental break-up a peak heat flow is considered. This was necessary for calibrating maturity profiles using vitrinite reflectance (VR) derived from modelled wells. A significant gas generation phase during Lower Jurassic is predicted. At modelled well locations, although renewed subsidence occurred during Tertiary to present day, a second phase of gas generation has not occurred, as past maximum temperatures were not exceeded. According to the interpreted regional seismic sections in the region, the area southeast of the 'Hinge Zone' can be regarded as the main kitchen area for gas generation from the Gondwana source rock. The petroleum system in the northwestern part of Bangladesh remains high risk due to uncertainties in source rock distribution and generation. (author)

  12. Optimization of Vertical Well Placement for Oil Field Development Based on Basic Reservoir Rock Properties using Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Tutuka Ariadji

    2012-07-01

    Full Text Available Comparing the quality of basic reservoir rock properties is a common practice to locate new infills or development wells for optimizing an oil field development using a reservoir simulation. The conventional technique employs a manual trial and error process to find new well locations, which proves to be time-consuming, especially, for a large field. Concerning this practical matter, an alternative in the form of a robust technique was introduced in order that time and efforts could be reduced in finding best new well locations capable of producing the highest oil recovery. The objective of the research was to apply Genetic Algorithm (GA in determining wells locations using reservoir simulation to avoid the manual conventional trial and error method. GA involved the basic rock properties, i.e., porosity, permeability, and oil saturation, of each grid block obtained from a reservoir simulation model, which was applied into a newly generated fitness function formulated through translating the common engineering practice in the reservoir simulation into a mathematical equation and then into a computer program. The maximum of the fitness value indicated a final searching of the best grid location for a new well location. In order to evaluate the performance of the generated GA program, two fields that had different production profile characteristics, namely the X and Y fields, were applied to validate the proposed method. The proposed GA method proved to be a robust and accurate method to find the best new well locations for field development. The key success of this proposed GA method is in the formulation of the objective function.

  13. Pore scale heterogeneity in the mineral distribution and reactive surface area of rocks

    Science.gov (United States)

    Lai, P. E.; Krevor, S. C.

    2013-12-01

    There are long-standing challenges in characterizing reactive transport in porous media at scales larger than individual pores. This hampers the prediction of the field-scale impact of geochemical processes on fluid flow [1]. This is a source of uncertainty for CO2 injection, which results in a reactive fluid-rock system, particularly in carbonate rock reservoirs. A potential cause is the inability of the continuum approach to incorporate the impact of heterogeneity in pore-scale reaction rates. This results in part from pore-scale heterogeneities in surface area of reactive minerals [2,3]. In this study we have created μm resolution 3D images of 3 sandstone and 4 carbonate rocks using x-ray microtomography. Using in-house image processing techniques and auxiliary characterisation with thin section, electron microscope and spectroscopic techniques we quantified the surface area of each mineral phase in the x-ray CT images. This quantification was validated against N2 BET surface area and He porosity measurements of the imaged samples. Distributions in reactive surface area for each mineral phase were constructed by calculating surface areas in thousands of randomly selected subvolume images of the total sample, each normalized to the pore volume in that image. In all samples, there is little correlation between the reactive surface area fraction and the volumetric fraction of a mineral in a bulk rock. Berea sandstone was far less heterogeneous and has a characteristic pore size at which a surface area distribution may be used to quantify heterogeneity. In carbonates, heterogeneity is more complex and surface area must be characterized at multiple length scales for an accurate description of reactive transport. [1] Maher, Steefel, Depaolo and Vianni (2006) Geochimica et Cosmochimica Acta, 70, 337-363 [2] Landrot, Ajo-Franklin, Yang, Cabrini and Steefel (2012) Chemical Geology 318-319, 113-125 [3] Li, Peters and Celia (2007) American Journal of Science 307, 1146

  14. Unsteady surface pressure measurements on a slender delta wing undergoing limit cycle wing rock

    Science.gov (United States)

    Arena, Andrew S., Jr.; Nelson, Robert C.

    1991-01-01

    An experimental investigation of slender wing limit cycle motion known as wing rock was investigated using two unique experimental systems. Dynamic roll moment measurements and visualization data on the leading edge vortices were obtained using a free to roll apparatus that incorporates an airbearing spindle. In addition, both static and unsteady surface pressure data was measured on the top and bottom surfaces of the model. To obtain the unsteady surface pressure data a new computer controller drive system was developed to accurately reproduce the free to roll time history motions. The data from these experiments include, roll angle time histories, vortex trajectory data on the position of the vortices relative to the model's surface, and surface pressure measurements as a function of roll angle when the model is stationary or undergoing a wing rock motion. The roll time history data was numerically differentiated to determine the dynamic roll moment coefficient. An analysis of these data revealed that the primary mechanism for the limit cycle behavior was a time lag in the position of the vortices normal to the wing surface.

  15. Halophilic archaea cultivated from surface sterilized middle-late eocene rock salt are polyploid.

    Directory of Open Access Journals (Sweden)

    Salla T Jaakkola

    Full Text Available Live bacteria and archaea have been isolated from several rock salt deposits of up to hundreds of millions of years of age from all around the world. A key factor affecting their longevity is the ability to keep their genomic DNA intact, for which efficient repair mechanisms are needed. Polyploid microbes are known to have an increased resistance towards mutations and DNA damage, and it has been suggested that microbes from deeply buried rock salt would carry several copies of their genomes. Here, cultivable halophilic microbes were isolated from a surface sterilized middle-late Eocene (38-41 million years ago rock salt sample, drilled from the depth of 800 m at Yunying salt mine, China. Eight unique isolates were obtained, which represented two haloarchaeal genera, Halobacterium and Halolamina. We used real-time PCR to show that our isolates are polyploid, with genome copy numbers of 11-14 genomes per cell in exponential growth phase. The ploidy level was slightly downregulated in stationary growth phase, but the cells still had an average genome copy number of 6-8. The polyploidy of halophilic archaea living in ancient rock salt might be a factor explaining how these organisms are able to overcome the challenge of prolonged survival during their entombment.

  16. Well-Posedness of a fully coupled thermo-chemo-poroelastic system with applications to petroleum rock mechanics

    Directory of Open Access Journals (Sweden)

    Tetyana Malysheva

    2017-05-01

    Full Text Available We consider a system of fully coupled parabolic and elliptic equations constituting the general model of chemical thermo-poroelasticity for a fluid-saturated porous media. The main result of this paper is the developed well-posedness theory for the corresponding initial-boundary problem arising from petroleum rock mechanics applications. Using the proposed pseudo-decoupling method, we establish, subject to some natural assumptions imposed on matrices of diffusion coefficients, the existence, uniqueness, and continuous dependence on initial and boundary data of a weak solution to the problem. Numerical experiments confirm the applicability of the obtained well-posedness results for thermo-chemo-poroelastic models with real-data parameters.

  17. Revegetation of Acid Rock Drainage (ARD) Producing Slope Surface Using Phosphate Microencapsulation and Artificial Soil

    Science.gov (United States)

    Kim, Jae Gon

    2017-04-01

    Oxidation of sulfides produces acid rock drainage (ARD) upon their exposure to oxidation environment by construction and mining activities. The ARD causes the acidification and metal contamination of soil, surface water and groundwater, the damage of plant, the deterioration of landscape and the reduction of slope stability. The revegetation of slope surface is one of commonly adopted strategies to reduce erosion and to increase slope stability. However, the revegetation of the ARD producing slope surface is frequently failed due to its high acidity and toxic metal content. We developed a revegetation method consisting of microencapsualtion and artificial soil in the laboratory. The revegetation method was applied on the ARD producing slope on which the revegetation using soil coverage and seeding was failed and monitored the plant growth for one year. The phosphate solution was applied on sulfide containing rock to form stable Fe-phosphate mineral on the surface of sulfide, which worked as a physical barrier to prevent contacting oxidants such as oxygen and Fe3+ ion to the sulfide surface. After the microencapsulation, two artificial soil layers were constructed. The first layer containing organic matter, dolomite powder and soil was constructed at 2 cm thickness to neutralize the rising acidic capillary water from the subsurface and to remove the dissolved oxygen from the percolating rain water. Finally, the second layer containing seeds, organic matter, nutrients and soil was constructed at 3 cm thickness on the top. After application of the method, the pH of the soil below the artificial soil layer increased and the ARD production from the rock fragments reduced. The plant growth showed an ordinary state while the plant died two month after germination for the previous revegetation trial. No soil erosion occurred from the slope during the one year field test.

  18. Optimum crushing level of blasted rock at the Prokop'evsk surface coal mine

    Energy Technology Data Exchange (ETDEWEB)

    Gemba, V.I.; Starkov, V.L.; Ustyuzhanin, V.S.

    1987-06-01

    Explains that improving the quality of rock crushing using blasting energy increases the efficiency of excavators and other mining equipment, reduces the energy required for scooping and loading tasks and hence reduces the cost of excavating and transporting rock. Investigations performed in surface mines in the Southern Urals and the Kuzbass coal sections showed that changing the mean linear dimensions of the lumps of blasted rock from 0.2 to 0.8 m increased the power consumption of a EhKG-4,6 excavator from 0.12 to 0.3 kWh/m/sup 3/ and that of loading from 0.1 to 1.56 kWh/m/sup 3/. Uses actual values for the efficiency and costs of blasting, excavation and transporting operations (presented in tabular form) as the basis for a comparative evaluation with the aim of determining how to achieve maximum cost-efficiency and, taking all factors into account, calculates that for the Prokop'evsk surface mine the optimum lump size is 0.4 m.

  19. Coseismic landslides reveal near-surface rock strength in a high-relief tectonically active setting

    Science.gov (United States)

    Gallen, Sean F; Clark, Marin K; Godt, Jonathan W.

    2014-01-01

    We present quantitative estimates of near-surface rock strength relevant to landscape evolution and landslide hazard assessment for 15 geologic map units of the Longmen Shan, China. Strength estimates are derived from a novel method that inverts earthquake peak ground acceleration models and coseismic landslide inventories to obtain material proper- ties and landslide thickness. Aggregate rock strength is determined by prescribing a friction angle of 30° and solving for effective cohesion. Effective cohesion ranges are from 70 kPa to 107 kPa for 15 geologic map units, and are approximately an order of magnitude less than typical laboratory measurements, probably because laboratory tests on hand-sized specimens do not incorporate the effects of heterogeneity and fracturing that likely control near-surface strength at the hillslope scale. We find that strength among the geologic map units studied varies by less than a factor of two. However, increased weakening of units with proximity to the range front, where precipitation and active fault density are the greatest, suggests that cli- matic and tectonic factors overwhelm lithologic differences in rock strength in this high-relief tectonically active setting.

  20. Mineralogy and source rock evaluation of the marine Oligo-Miocene sediments in some wells in the Nile Delta and North Sinai, Egypt

    Science.gov (United States)

    El sheikh, Hassan; Faris, Mahmoud; Shaker, Fatma; Kumral, Mustafa

    2016-06-01

    This paper aims to study the mineralogical composition and determine the petroleum potential of source rocks of the Oligocene-Miocene sequence in the Nile Delta and North Sinai districts. The studied interval in the five wells can be divided into five rock units arranged from the top to base; Qawasim, Sidi Salem, Kareem, Rudeis, and Qantara formations. The bulk rock mineralogy of the samples was investigated using X-Ray Diffraction technique (XRD). The results showed that the sediments of the Nile Delta area are characterized by the abundance of quartz and kaolinite with subordinate amounts of feldspars, calcite, gypsum, dolomite, and muscovite. On the other hand, the data of the bulk rock analysis at the North Sinai wells showed that kaolinite, quartz, feldspar and calcite are the main constituents associated with minor amounts of dolomite, gypsum, mica, zeolite, and ankerite. Based on the organic geochemical investigations (TOC and Rock-Eval pyrolysis analyses), all studied formations in both areas are thermally immature but in the Nile delta area, Qawasim, Sidi Salem and Qantara formations (El-Temsah-2 Well) are organically-rich and have a good petroleum potential (kerogen Type II-oil-prone), while Rudeis Formation is a poor petroleum potential source rock (kerogen Type III-gas-prone). In the North Sinai area, Qantara Formation has a poor petroleum potential (kerogen Type III-gas-prone) and Sidi Salem Formation (Bardawil-1 Well) is a good petroleum potential source rock (kerogen Type II-oil-prone).

  1. The effects of Concentration and Salinity on Polymer Adsorption Isotherm at Sandstone Rock Surface

    Science.gov (United States)

    Ali, M.; Ben Mahmud, H.

    2015-04-01

    Adsorption of hydrolyzed polyacrylamide (HPAM) polymers on sandstone rock surface was studied by static adsorption experiments. Total of 10 Runs of static experiments were conducted in test tubes by mixing the desired solution with crushed rock sample, at temperature of 25 °C, and salinity range from 0-4 wt%. The results are in conformity with Langmuir's isotherm. Ten different isotherms were generated at each Run. The initial polymer concentration was varied from 0.3-2.1 g/l. The effects of salinity have been studied by observation on Langmuir adsorption coefficients (Y and K). The results show that the adsorption coefficient (Y) was found to have linear relationship with salinity. The adsorption coefficient (K) was found to be related to salinity by a quadratic relationship.

  2. A Genetic Algorithm for Locating the Multiscale Critical Slip Surface in Jointed Rock Mass Slopes

    Directory of Open Access Journals (Sweden)

    Qiang Xu

    2014-01-01

    Full Text Available The joints have great influence on the strength of jointed rock mass and lead to the multiscale, nonhomogeneous, and anisotropic characteristics. In order to consider these effects, a new model based on a genetic algorithm is proposed for locating the critical slip surface (CSS in jointed rock mass slope (JRMS from its stress field. A finite element method (FEM was employed to analyze the stress field. A method of calculating the mechanical persistence ratio (MPR was used. The calculated multiscale and anisotropic characteristics of the MPR were used in the fitness function of genetic algorithm (GA to calculate the factor of safety. The GA was used to solve optimization problems of JRMS stability. Some numerical examples were given. The results show that the multiscale and anisotropic characteristics of the MPR played an important role in locating the CSS in JRMS. The proposed model calculated the CSS and the factor of safety of the slope with satisfactory precision.

  3. Control Mechanism of Rock Burst in the Floor of Roadway Driven along Next Goaf in Thick Coal Seam with Large Obliquity Angle in Deep Well

    Directory of Open Access Journals (Sweden)

    Yunhai Cheng

    2015-01-01

    Full Text Available This paper deals with the theoretical aspects combined with stress analysis over the floor strata of coal seam and the calculation model for the stress on the coal floor. Basically, this research presents the relevant results obtained for the rock burst prevention in the floor of roadway driven along next goaf in the exploitation of thick coal seam with large obliquity in deep well and rock burst tendency. The control mechanism of rock burst in the roadway driven along next goaf is revealed in the present work. That is, the danger of rock burst can be removed by changing the stress environment for the energy accumulation of the floor and by reducing the impact on the roadway floor from the strong dynamic pressure. This result can be profitable being used at the design stage of appropriate position of roadway undergoing rock burst tendency in similar conditions. Based on the analysis regarding the control mechanism, this paper presents a novel approach to the prevention of rock burst in roadway floor under the above conditions. That is, the return airway is placed within the goaf of the upper working face that can prevent the rock burst effectively. And in this way, mining without coal pillar in the thick coal seam with large obliquity and large burial depth (over a thousand meters is realized. Practice also proves that the rock burst in the floor of roadway driven along next goaf is controlled and solved.

  4. Influence of laser scanner range measurement noise on the quantification of rock surface roughness

    Science.gov (United States)

    Khoshelham, Kourosh; Altundag, Dogan

    2010-05-01

    The roughness of rock surfaces is traditionally measured by using manual tools such as carpenter's comp and compass and disc clinometers. The manual measurements are limited to small samples at accessible parts of the rock. Terrestrial laser scanning is an attractive alternative measurement technique, which offers large coverage, high resolution, and the ability to reach inaccessible high rock faces. The application of laser scanning to the study of rock surface roughness faces a major challenge: the inherent range imprecision hinders the quantification of roughness parameters. In practice, when roughness is in millimeter scale it is often lost in the range measurement noise. The parameters derived from the data, therefore, reflect noise rather than the actual roughness of the surface. In this paper, we investigate the influence of laser scanner range measurement noise on the quantification of rock surfaces roughness. We show that measurement noise leads to the overestimation of roughness parameters. We also demonstrate the application of wavelet de-noising method to eliminating noise from laser scanner data and deriving realistic roughness parameters. A slightly metamorphosed limestone rock in the east bank of the Meuse River in southern Belgium was scanned with a Faro LS880 terrestrial laser scanner. The scanner was positioned at approximately 5 meters distance to the rock surface, and operated at the highest possible angular resolution, i.e. 0.009 degrees. The resulting point cloud contained about 1.2 million points on the rock surface with a point-spacing of 1 mm on average. According to the technical specifications of the laser scanner, the nominal range precision at a perpendicular incidence angle, which was roughly the case in our scan, is between 0.7 mm and 5.2 mm respectively for objects of 90% and 10% reflectivity at a distance of 10 m. To serve as reference roughness data were also collected manually along three profiles on the rock surface by using a

  5. Determining pore length scales and pore surface relaxivity of rock cores by internal magnetic fields modulation at 2MHz NMR.

    Science.gov (United States)

    Liu, Huabing; Nogueira d'Eurydice, Marcel; Obruchkov, Sergei; Galvosas, Petrik

    2014-09-01

    Pore length scales and pore surface relaxivities of rock cores with different lithologies were studied on a 2MHz Rock Core Analyzer. To determine the pore length scales of the rock cores, the high eigenmodes of spin bearing molecules satisfying the diffusion equation were detected with optimized encoding periods in the presence of internal magnetic fields Bin. The results were confirmed using a 64MHz NMR system, which supports the feasibility of high eigenmode detection at fields as low as 2MHz. Furthermore, this methodology was combined with relaxometry measurements to a two-dimensional experiment, which provides correlation between pore length and relaxation time. This techniques also yields information on the surface relaxivity of the rock cores. The estimated surface relaxivities were then compared to the results using an independent NMR method.

  6. Chromium isotopes in siliciclastic sediments and sedimentary rocks as a proxy for Earth surface redox

    Science.gov (United States)

    Reinhard, C. T.; Planavsky, N. J.; Wang, X.; Owens, J. D.; Johnson, T. M.; Fischer, W. W.; Lyons, T. W.

    2013-12-01

    Chromium (Cr) isotopes are an emerging and potentially promising proxy for tracking redox processes at Earth's surface. However, recent efforts to reconstruct the Cr isotope record through time have primarily focused on sporadically deposited iron-rich chemical sediments, with large temporal gaps and limited capacity to explore the Cr isotope record relative to modern and recent marine processes. However, the basic inorganic chemistry of Cr suggests that anoxic marine basins factor prominently in the global Cr cycle, and that likewise sediments deposited within anoxic basins may offer an unexplored Cr isotope archive throughout Earth's history. We present authigenic δ53Cr data from sediments of the Cariaco Basin, Venezuela--a ';type' environment on the modern Earth for large, perennially anoxic basins with relatively strong hydrological connections to the global ocean. Combined with currently available constraints on the δ53Cr composition of modern Atlantic seawater, these data are consistent with the hypothesis that anoxic marine basins can serve as a chemical archive of the first-order features of seawater δ53Cr variation. We employ a simple quantitative model to explore the implications of this hypothesis for global Cr isotope mass balance and the possible utility of authigenic δ53Cr in anoxically deposited siliciclastic sediments and sedimentary rocks as a global paleoredox proxy. Our focus is a basic analysis of the primary controls on seawater δ53Cr as related to both the marine redox landscape and the processes involved in the weathering and aqueous-particulate transport of Cr at Earth's surface. As a case study, we provide analysis of new bulk δ53Cr data through a Cretaceous Oceanic Anoxic Event (OAE-2), which shows a well-defined ~1.0‰ negative excursion during the event coupled with evidence for a drawdown of the marine Cr reservoir. We present a conceptual model to explain these observations, and interpret this shift to suggest a shutdown of

  7. Forming chemical composition of surface waters in the Arctic as "water - rock" interaction. Case study of lake Inari and river Paz

    Science.gov (United States)

    Mazukhina, Svetlana; Sandimirov, Sergey; Pozhilenko, Vladimir; Ivanov, Stanislav; Maksimova, Viktoriia

    2017-04-01

    substances. A set of solid phases of the multisystem is formed with the mineral composition of the crystalline rocks of the Fennoscandian (Baltic) shield taken into account. The processes of forming the surface waters in the "water - rock - atmosphere" system depending on the degree of interaction (ξ) of rocks with aqueous solutions under open conditions (100 kg of atmosphere, 1000 kg of water, T-5oC, P-1 bar and rock (100 g) - the rock average composition: 1) Inari terrane rocks, 2) granulites of the Lapland granulite belt were investigated. Clarke concentrations of S, C, F, Zn, Ni, Pb, Cu (Vinogradov, 1962) were taken into account in order to determine their influence on forming the chemical composition of water solutions, and water migration coefficients (Perelman, 1989). Comparison of the modeling results with the monitoring results of the source of river Paz shows that the chemical composition of waters of lake Inari as well as the upper flow of river Paz is formed by interactions of surface waters, ground waters, and fissure waters with granulites of the Lapland granulite belt, as well as gneisses, diorites and granitoids of Inari terrane of the northern Fennoscandia. Thermodynamic modeling determined that the chemical composition of surface waters is formed as a result of interaction of atmospheric precipitation with intrusive and sedimentary rocks of the northern Fennoscandia, containing clarke concentrations of S, C, F, Zn, Ni, Pb, Cu. The obtained model solutions indicate that surface waters are formed within the considered system as a result of "water-rock-atmosphere" interaction.

  8. A study on chemical interactions between waste fluid, formation water, and host rock during deep well injection

    Energy Technology Data Exchange (ETDEWEB)

    Spycher, Nicolas; Larkin, Randy

    2004-05-14

    A new disposal well was drilled in the vicinity of an injection well that had been in operation for 12 years. The drilling activities provided an opportunity to assess the fate and transport of waste products injected in the nearby well, and the impact, if any, on the host geologic formation. The origin of the fluid collected while drilling the new well and the interaction between injected waste and the formation were investigated using analyses of formation waters, waste, and formation minerals, by applying traditional graphical methods and sophisticated numerical models. This approach can be used to solve a wide range of geochemical problems related to deep well injection of waste. Trilinear Piper diagrams, Stiff diagrams, and correlation plots show that the chemical characteristics of recovered fluid at the new well are similar to those of formation water. The concentrations of most major constituents in the fluid appear diluted when compared to formation water sampled at other locations. This could be explained by mixing with waste, which is less saline than formation water. However, the waste injected near the new well consists primarily of ammonia and sulfate, and these waste constituents are not found at concentrations elevated enough to suggest that significant mixing of formation water with waste has occurred. To determine whether chemical interactions between injected waste and formation could explain the chemistry of fluid recovered from the new well, we simulated the chemical reaction between waste, formation water, and the formation rock by numerical modeling. Initial modeling calculations were done using a multicomponent geochemical reaction-path model to simulate fresh waste reacting with the formation. A more complex simulation coupling flow, transport, and reaction was then run using a multicomponent geochemical reactive transport model. These numerical simulations were carried out to calculate porosity changes and evaluate chemical processes

  9. 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.

  10. Evaluation of the nature, origin and potentiality of the subsurface Middle Jurassic and Lower Cretaceous source rocks in Melleiha G-1x well, North Western Desert, Egypt

    Directory of Open Access Journals (Sweden)

    Mohamed M. El Nady

    2015-09-01

    Full Text Available The present work aims to evaluate the nature and origin of the source rock potentiality of subsurface Middle Jurassic and Lower Cretaceous source rocks in Melleiha G-1x well. This target was achieved throughout the evaluation of total organic carbon, rock Eval pyrolysis and vitrinite reflectance for fifteen cutting samples and three extract samples collected from Khatatba, Alam El Bueib and Kharita formations in the studied well. The result revealed that the main hydrocarbon of source rocks, for the Middle Jurassic (Khatatba Fm. is mainly mature, and has good capability of producing oil and minor gas. Lower Cretaceous source rocks (Alam El Bueib Fm. are mature, derived from mixed organic sources and have fair to good capability to generate gas and oil. Kharita Formation of immature source rocks originated from terrestrial origin and has poor to fair potential to produce gas. This indicates that Khatatba and Alam El Bueib formations take the direction of increasing maturity far away from the direction of biodegradation and can be considered as effective source potential in the Melleiha G-1x well.

  11. Using gravity data to estimate the density of surface rocks of Taiwan region

    Science.gov (United States)

    Lo, Y. T.; Horng-Yen, Y.

    2016-12-01

    Surface rock density within terrain correction step is one of the important parameters for obtaining Bouguer anomaly map. In the past study, we obtain the Bouguer anomaly map considering the average density correction of a wide range of the study area. In this study, we will be the better estimate for the correction of the density of each observation point. A correction density that coincides with surface geology is in order to improve the accuracy of the cloth cover anomaly map. The main idea of estimating correction of the density using gravity data statistics are two method, g-H relationship and Nettleton density profile method, respectively. The common advantages of these methods are in the following: First, density estimating is calculated using existing gravity observations data, it may be avoided the trouble of directly measure the rock density. Second, after the establishment the measuring point s of absolute gravity value, latitude, longitude and elevation into the database, you can always apply its database of information and terrain data with the value to calculate the average rock density on any range. In addition, each measuring point and numerical data of each terrain mesh are independent, if found to be more accurate gravity or terrain data, simply update a document data alone, without having to rebuild the entire database. According the results of estimating density distribution map, the trends are broadly distributed close to Taiwan Geology Division. The average density of the backbone mountain region is about 2.5 to 2.6 g/cm^3, the average density of east Central Mountain Range and Hsuehshan Range are about 2.3 to 2.5 g/cm^3, compared with the western foothills of 2.1-2.3 g/cm^3, the western plains is from 1.8 to 2.0 g/cm^3.

  12. The implementation of the algorithm of break surface simulation while designing the well breaking

    Directory of Open Access Journals (Sweden)

    Lukichev S.V.

    2015-06-01

    Full Text Available A method of calculating the break surface formed as a result of blast-hole rings' short-delay blasting has been developed. The method is based on simulation modeling of a process of broken rock separation from rock mass. A modeling tool has been implemented as a part of the module for designing cave large-scale blasts included in MINEFRAME software package. It has been shown that the tool can evaluate possible outcomes of the project of cave large-scale blast properly

  13. Improved response surface method and its application in stability reliability degree analysis of tunnel surrounding rock

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    An approach of limit state equation for surrounding rock was put forward based on deformation criterion. A method of symmetrical sampling of basic random variables adopted by classical response surface method was mended, and peak value and deflection degree of basic random variables distribution curve were took into account in the mended sampling method. A calculation way of probability moment, based on mended Rosenbluth method, suitable for non-explicit performance function was put forward.The first, second, third and fourth order moments of functional function value were calculated by mended Rosenbluth method through the first, second, third and fourth order moments of basic random variable. A probability density the function(PDF) of functional function was deduced through its first, second, third and fourth moments, the PDF in the new method took the place of the method of quadratic polynomial to approximate real functional function and reliability probability was calculated through integral by the PDF for random variable of functional function value in the new method. The result shows that the improved response surface method can adapt to various statistic distribution types of basic random variables, its calculation process is legible and need not iterative circulation. In addition, a stability probability of surrounding rock for a tunnel was calculated by the improved method,whose workload is only 30% of classical method and its accuracy is comparative.

  14. Well logging identification of gypsum cap rocks in middle-upper Yangtze region%中上扬子区膏岩盖层的测井识别

    Institute of Scientific and Technical Information of China (English)

    冯琼; 魏水建

    2011-01-01

    针对中、上扬子区膏岩盖层测井响应特征,充分利用地质、录井、岩心分析、测井等资料,采用岩心刻度测井的方法,建立了膏岩盖层参数测井解释模型,并对该区膏岩盖层进行了测井解释与评价;建立了一套适合川东北地区膏岩盖层的测井识别方法,从而实现了盖层从定性识别到盖层参数的定量评价,为盖层的地球物理预测研究提供了重要的基础参数.%Based on well logging response characteristics of gypsum cap rocks in the middle- upper Yangtze region, with geology, well logging, core analysis and logging data, it was established in this paper a logging interpretation model of gypsum cap rock parameters using the core calibration logging method.The gypsum cap rocks in the study region were interpreted and evaluated. A new set of logging identification method suitable for gypsum cap rocks in the Northeast Sichuan Basin was put forward. The qualitative identification and the quantitative evaluation of cap rocks were done, offering important basis parameters for the geophysical prediction researches of cap rocks.

  15. Surface-groundwater interactions in hard rocks in Sardon Catchment of western Spain: an integrated modeling approach

    NARCIS (Netherlands)

    Tanvir Hassan, S.M.; Lubczynski, M.; Niswonger, R.G.; Su, Zhongbo

    2014-01-01

    The structural and hydrological complexity of hard rock systems (HRSs) affects dynamics of surface–groundwater interactions. These complexities are not well described or understood by hydrogeologists because simplified analyses typically are used to study HRSs. A transient, integrated hydrologic

  16. Failure characteristics of surface vertical wells for relieved coal gas and their influencing factors in Huainan mining area

    Institute of Scientific and Technical Information of China (English)

    Xu Hongjie; Sang Shuxun; Fang Liangcai; Huang Huazhou; Ren Bo

    2011-01-01

    Based on data from through-hole and logging, we studied the failure characteristics of surface drainage wells for relieved coal gas in Huainan mining area and its influencing factors. The results show that the damaged positions of drainage wells are mainly located at the thick clay layer in the low alluvium and the lithological interface in the upper section of bedrock in west mining area. The failure depth of casing is 244-670 m and concentrates at about 270-460 m deep. These damaged positions are mainly located in the bending zone according to three zones of rock layers in the vertical section above the roof divided. Generally, the casing begins to deform or damage before the face line about 30-150 m. Special formation structure and rock mass properties are the direct causes of the casing failure, high mining height and fast advancing speed are fundamental reasons for rock mass damage. However, the borehole configuration and spacing to the casing failure are not very clear.

  17. 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.

  18. Application of well log analysis for source rock evaluation in the Duwi Formation, Southern Gulf of Suez, Egypt

    Science.gov (United States)

    El Sharawy, Mohamed S.; Gaafar, Gamal R.

    2012-05-01

    Several models were developed to use the conventional wireline logs for evaluating the thermal maturity of the source rock and calculating the total organic carbon (TOC) content. Application of these models for the Duwi Formation, southern Gulf of Suez, Egypt, is the main purpose of this paper. Gamma ray, density, sonic, resistivity and neutron are the commonly used wireline logs to identify and quantify source rock. The results, which compared with the results obtained from the Rock-Eval pyrolysis show that cautions must be taken into consideration when applied these models because most of the models are empirical and their validation takes place under certain conditions. It can be concluded that the Duwi Formation represents very good source rock capable of generating a significant amount of hydrocarbon of oil-prone type II. The kerogen is waxy sapropel related to marine plankton deposited under reduced condition.

  19. Modeling and interpretation of Q logs in carbonate rock using a double porosity model and well logs

    Science.gov (United States)

    Parra, Jorge O.; Hackert, Chris L.

    2006-03-01

    Attenuation data extracted from full waveform sonic logs is sensitive to vuggy and matrix porosities in a carbonate aquifer. This is consistent with the synthetic attenuation (1 / Q) as a function of depth at the borehole-sonic source-peak frequency of 10 kHz. We use velocity and densities versus porosity relationships based on core and well log data to determine the matrix, secondary, and effective bulk moduli. The attenuation model requires the bulk modulus of the primary and secondary porosities. We use a double porosity model that allows us to investigate attenuation at the mesoscopic scale. Thus, the secondary and primary porosities in the aquifer should respond with different changes in fluid pressure. The results show a high permeability region with a Q that varies from 25 to 50 and correlates with the stiffer part of the carbonate formation. This pore structure permits water to flow between the interconnected vugs and the matrix. In this region the double porosity model predicts a decrease in the attenuation at lower frequencies that is associated with fluid flowing from the more compliant high-pressure regions (interconnected vug space) to the relatively stiff, low-pressure regions (matrix). The chalky limestone with a low Q of 17 is formed by a muddy porous matrix with soft pores. This low permeability region correlates with the low matrix bulk modulus. A low Q of 18 characterizes the soft sandy carbonate rock above the vuggy carbonate. This paper demonstrates the use of attenuation logs for discriminating between lithology and provides information on the pore structure when integrated with cores and other well logs. In addition, the paper demonstrates the practical application of a new double porosity model to interpret the attenuation at sonic frequencies by achieving a good match between measured and modeled attenuation.

  20. Phylogeny of rock-inhabiting fungi related to Dothideomycetes

    NARCIS (Netherlands)

    Ruibal, C.; Gueidan, C.; Selbmann, L.; Gorbushina, A.A.; Crous, P.W.; Groenewald, J.Z.; Muggia, L.; Grube, M.; Isola, D.; Schoch, C.L.; Staley, J.T.; Lutzoni, F.; Hoog, de G.S.

    2009-01-01

    The class Dothideomycetes (along with Eurotiomycetes) includes numerous rock-inhabiting fungi (RIF), a group of ascomycetes that tolerates surprisingly well harsh conditions prevailing on rock surfaces. Despite their convergent morphology and physiology, RIF are phylogenetically highly diverse in Do

  1. 井矿盐生产节能减排浅析%Analysis of energy saving and emission reduction in well and rock salt production

    Institute of Scientific and Technical Information of China (English)

    朱旭初

    2014-01-01

    文章依据井矿盐生产的实际情况,从工艺、设备、操作、管理4个方面分析了井矿盐生产节能减排的具体措施和办法。%The management of specific measures and methods of energy saving and emission reduction in well and rock salt production was studied from the four aspects of process such as emission, equipment, operation,management based on the actual situations of well and rock salt industry production.

  2. 'Escher' Rock

    Science.gov (United States)

    2004-01-01

    [figure removed for brevity, see original site] Chemical Changes in 'Endurance' Rocks [figure removed for brevity, see original site] Figure 1 This false-color image taken by NASA's Mars Exploration Rover Opportunity shows a rock dubbed 'Escher' on the southwestern slopes of 'Endurance Crater.' Scientists believe the rock's fractures, which divide the surface into polygons, may have been formed by one of several processes. They may have been caused by the impact that created Endurance Crater, or they might have arisen when water leftover from the rock's formation dried up. A third possibility is that much later, after the rock was formed, and after the crater was created, the rock became wet once again, then dried up and developed cracks. Opportunity has spent the last 14 sols investigating Escher, specifically the target dubbed 'Kirchner,' and other similar rocks with its scientific instruments. This image was taken on sol 208 (Aug. 24, 2004) by the rover's panoramic camera, using the 750-, 530- and 430-nanometer filters. The graph above shows that rocks located deeper into 'Endurance Crater' are chemically altered to a greater degree than rocks located higher up. This chemical alteration is believed to result from exposure to water. Specifically, the graph compares ratios of chemicals between the deep rock dubbed 'Escher,' and the more shallow rock called 'Virginia,' before (red and blue lines) and after (green line) the Mars Exploration Rover Opportunity drilled into the rocks. As the red and blue lines indicate, Escher's levels of chlorine relative to Virginia's went up, and sulfur down, before the rover dug a hole into the rocks. This implies that the surface of Escher has been chemically altered to a greater extent than the surface of Virginia. Scientists are still investigating the role water played in influencing this trend. These data were taken by the rover's alpha particle X-ray spectrometer.

  3. 'Escher' Rock

    Science.gov (United States)

    2004-01-01

    [figure removed for brevity, see original site] Chemical Changes in 'Endurance' Rocks [figure removed for brevity, see original site] Figure 1 This false-color image taken by NASA's Mars Exploration Rover Opportunity shows a rock dubbed 'Escher' on the southwestern slopes of 'Endurance Crater.' Scientists believe the rock's fractures, which divide the surface into polygons, may have been formed by one of several processes. They may have been caused by the impact that created Endurance Crater, or they might have arisen when water leftover from the rock's formation dried up. A third possibility is that much later, after the rock was formed, and after the crater was created, the rock became wet once again, then dried up and developed cracks. Opportunity has spent the last 14 sols investigating Escher, specifically the target dubbed 'Kirchner,' and other similar rocks with its scientific instruments. This image was taken on sol 208 (Aug. 24, 2004) by the rover's panoramic camera, using the 750-, 530- and 430-nanometer filters. The graph above shows that rocks located deeper into 'Endurance Crater' are chemically altered to a greater degree than rocks located higher up. This chemical alteration is believed to result from exposure to water. Specifically, the graph compares ratios of chemicals between the deep rock dubbed 'Escher,' and the more shallow rock called 'Virginia,' before (red and blue lines) and after (green line) the Mars Exploration Rover Opportunity drilled into the rocks. As the red and blue lines indicate, Escher's levels of chlorine relative to Virginia's went up, and sulfur down, before the rover dug a hole into the rocks. This implies that the surface of Escher has been chemically altered to a greater extent than the surface of Virginia. Scientists are still investigating the role water played in influencing this trend. These data were taken by the rover's alpha particle X-ray spectrometer.

  4. [Quantitative estimation of CaO content in surface rocks using hyperspectral thermal infrared emissivity].

    Science.gov (United States)

    Zhang, Li-Fu; Zhang, Xue-Wen; Huang, Zhao-Qiang; Yang, Hang; Zhang, Fei-Zhou

    2011-11-01

    The objective of the present paper is to study the quantitative relationship between the CaO content and the thermal infrared emissivity spectra. The surface spectral emissivity of 23 solid rocks samples were measured in the field and the first derivative of the spectral emissivity was also calculated. Multiple linear regression (MLR), principal component analysis (PCR) and partial least squares regression (PLSR) were modeled and the regression results were compared. The results show that there is a good relationship between CaO content and thermal emissivity spectra features; emissivities become lower when CaO content increases in the 10.3-13 mm region; the first derivative spectra have a better predictive ability compared to the original emissivity spectra.

  5. Rock Art

    OpenAIRE

    Huyge, Dirk

    2009-01-01

    Rock art, basically being non-utilitarian, non-textual anthropic markings on natural rock surfaces, was an extremely widespread graphical practice in ancient Egypt. While the apogee of the tradition was definitely the Predynastic Period (mainly fourth millennium BCE), examples date from the late Palaeolithic (c. 15,000 BCE) until the Islamic era. Geographically speaking, “Egyptian” rock art is known from many hundreds of sites along the margins of the Upper Egyptian and Nubian Nile Valley and...

  6. Surface motion of active rock glaciers in the Sierra Nevada, California, USA: inventory and a case study using InSAR

    Science.gov (United States)

    L. Liu; C.I. Millar; R.D. Westfall; H.A. Zebker

    2013-01-01

    Despite the abundance of rock glaciers in the Sierra Nevada of California, USA, few efforts have been made to measure their surface flow. Here we use the interferometric synthetic aperture radar (InSAR) technique to compile a~benchmark inventory describing the kinematic state of 59 active rock glaciers in this region. Statistically, these rock glaciers moved at...

  7. Modelling fault surface roughness and fault rocks thickness evolution with slip: calibration based on field and laboratory data

    Science.gov (United States)

    Bistacchi, A.; Tisato, N.; Spagnuolo, E.; Nielsen, S. B.; Di Toro, G.

    2012-12-01

    The architecture and physical properties of fault zones evolve with slip and time. Such evolution, which progressively modifies the type and thickness of fault rocks, the fault surface roughness, etc., controls the rheology of fault zones (seismic vs. aseismic) and earthquakes (main shock magnitude, coseismic slip distribution, stress drop, foreshock and aftershock sequence evolution, etc.). Seismogenic faults exhumed from 2-10 km depth and hosted in different rocks (carbonates, granitoids, etc.) show a (1) self-affine (Hurst exponent H definition of "wear" (including every process that destroys geometrical asperities and produces fault rocks). The output roughness and fault rock thickness depend on two parameters: (1) wear rate and (2) wear products (fault rocks) accumulation rate. To test the model we used surface roughness, fault rock thickness, and slip data collected in the field (Gole Larghe Fault Zone, Italian Southern Alps) and in the lab (rotary shear experiments on different rocks). The model was successful in predicting the first-order evolution of roughness and of fault rock thickness with slip in both natural and experimental datasets. Differences in best-fit model parameters (wear rate and wear products accumulation rate) were satisfactorily explained in terms of different deformation processes (e.g. frictional melting vs. cataclasis) and experimental conditions (unconfined vs. confined). Since the model is based on geometrical and volume-conservation considerations (and not on a particular deformation mechanism), we conclude that the surface roughness and fault-rock thickness after some slip is mostly determined by the initial roughness (measured over several orders of magnitude in wavelength), rather than the particular deformation process (cataclasis, melting, etc.) activated during faulting. Conveniently, since the model can be applied (under certain conditions) to surfaces which depart from self-affine roughness, the model parameters can be

  8. WELL LOGGING EVALUATION OF MARINE HYDROCARBON SOURCE ROCK IN TAZHONG AREA%塔中地区海相烃源岩测井评价

    Institute of Scientific and Technical Information of China (English)

    雷涛; 周文; 邓虎成; 赵安坤; 杨艺; 熊川

    2011-01-01

    To the low organic abundance and strong heterogeneity of the marine hydrocarbon source rock, this paper analyzes the well logging response characteristics of the marine hydrocarbon source rock in Tazhong area, and builds the plate for quantitative identification of Ordovician source rock in Tazhong area and the classification and identification model for marine source rock in the studied area. In the evaluation of organic matter abundance, the elastic parameters of hydrocarbon source rock, the ratio of uranium and thorium content, the difference of natural gamma, and the resistivity in Tazhong area are used as the input layers, and a BP neural network model based on the genetic algorithm is built. Practice shows that the TOC value predicated by this method is as accurate and reliable as the rock sample analysis result, providing the basis for the evaluation of effective hydrocarbon source rock.%针对海相烃源岩具有有机质丰度低和非均质性强的特点,分析了塔中地区海相烃源岩的测井响应特征,建立了塔中奥陶系烃源岩定量识别的图版及适合研究区海相烃源岩的分类识别模型.在有机质丰度评价方面,利用塔中地区烃源岩弹性参数、铀钍含量比、自然伽马的差值及电阻率作为输入层,建立了基于遗传算法的BP神经网络模型.实践表明,采用该方法预测的TOC值与岩石样品分析结果同样精确可靠,为评价有效烃源岩提供了依据.

  9. 4D reservoir characterization using well log data for feasible CO2-enhanced oil recovery at Ankleshwar, Cambay Basin - A rock physics diagnostic and modeling approach

    Science.gov (United States)

    Ganguli, Shib Sankar; Vedanti, Nimisha; Dimri, V. P.

    2016-12-01

    In recent years, rock physics modeling has become an integral part of reservoir characterization as it provides the fundamental relationship between geophysical measurements and reservoir rock properties. These models are also used to quantify the effect of fluid saturation and stress on reservoir rocks by tracking the changes in elastic properties during production. Additionally, various rock physics models can be applied to obtain the information of rock properties away from existing drilled wells, which can play a crucial role in the feasibility assessment of CO2-enhanced oil recovery (EOR) operation at field. Thus, the objective of this study is to develop a rock-physics model of the Ankleshwar reservoir to predict the reservoir response under CO2-EOR. The Ankleshwar oil field is a mature field situated in Cambay Basin (Western India) that witnessed massive peripheral water flooding for around 40 years. Since the field was under water flooding for a long term, reasonable changes in reservoir elastic properties might have occurred. To identify potential reservoir zone with significant bypassed (or residual) oil saturation, we applied the diagnostic rock physics models to two available wells from the Ankleshwar oil field. The results clearly indicate transitions from clean sands to shaly sands at the base, and from sandy shale to pure shale at the top of the reservoir pay zone, suggesting a different seismic response at the top when compared to the base of the reservoir in both the wells. We also found that clay content and sorting affects the elastic properties of these sands, indicating different depositional scenario for the oil sands encountered in the Ankleshwar formation. Nevertheless, the rock physics template (RPT) analysis of the well data provides valuable information about the residual oil zone, a potential target for CO2-EOR. Further, a 4D reservoir characterization study has been conducted to assess the seismic detectability of CO2-EOR, and we

  10. Electrical conductivity of lunar surface rocks - Laboratory measurements and implications for lunar interior temperatures

    Science.gov (United States)

    Schwerer, F. C.; Huffman, G. P.; Fisher, R. M.; Nagata, T.

    1974-01-01

    Results are reported for laboratory measurements of the dc and low-frequency ac electrical conductivity of three lunar rocks with ferrous iron contents of 5 to 26 wt %. The measurements were made at temperatures ranging from 20 to 1000 C, and Mossbauer spectroscopy was used to determine the dependence of electrical conductivity on furnace atmosphere. It is found that the magnitude of electrical conductivity generally increases with increasing iron content. A comparison of the data on these samples with data on terrestrial olivines and pyroxenes shows that the electrical conductivity of anhydrous silicate minerals is influenced primarily by the concentration, oxidation state, and distribution of iron, while the silicate crystal structure is only of secondary importance. Lunar interior temperatures are deduced from experimental lunar conductivity profiles, and the resulting temperature-depth profiles are found to be consistent with those calculated for two different lunar evolutionary models as well as with various experimental constraints.

  11. Creating potentiometric surfaces from combined water well and oil well data in the midcontinent of the United States

    Science.gov (United States)

    Gianoutsos, Nicholas J.; Nelson, Philip H.

    2013-01-01

    For years, hydrologists have defined potentiometric surfaces using measured hydraulic-head values in water wells from aquifers. Down-dip, the oil and gas industry is also interested in the formation pressures of many of the same geologic formations for the purpose of hydrocarbon recovery. In oil and gas exploration, drillstem tests (DSTs) provide the formation pressure for a given depth interval in a well. These DST measurements can be used to calculate hydraulic-head values in deep hydrocarbon-bearing formations in areas where water wells do not exist. Unlike hydraulic-head measurements in water wells, which have a low number of problematic data points (outliers), only a small subset of the DST data measure true formation pressures. Using 3D imaging capabilities to view and clean the data, we have developed a process to estimate potentiometric surfaces from erratic DST data sets of hydrocarbon-bearing formations in the midcontinent of the U.S. The analysis indicates that the potentiometric surface is more readily defined through human interpretation of the chaotic DST data sets rather than through the application of filtering and geostatistical analysis. The data are viewed as a series of narrow, 400-mile-long swaths and a 2D viewer is used to select a subset of hydraulic-head values that represent the potentiometric surface. The user-selected subsets for each swath are then combined into one data set for each formation. These data are then joined with the hydraulic-head values from water wells to define the 3D potentiometric surfaces. The final product is an interactive, 3D digital display containing: (1) the subsurface structure of the formation, (2) the cluster of DST-derived hydraulic head values, (3) the user-selected subset of hydraulic-head values that define the potentiometric surface, (4) the hydraulic-head measurements from the corresponding shallow aquifer, (5) the resulting potentiometric surface encompassing both oil and gas and water wells, and (6

  12. Art Rocks with Rock Art!

    Science.gov (United States)

    Bickett, Marianne

    2011-01-01

    This article discusses rock art which was the very first "art." Rock art, such as the images created on the stone surfaces of the caves of Lascaux and Altimira, is the true origin of the canvas, paintbrush, and painting media. For there, within caverns deep in the earth, the first artists mixed animal fat, urine, and saliva with powdered minerals…

  13. Art Rocks with Rock Art!

    Science.gov (United States)

    Bickett, Marianne

    2011-01-01

    This article discusses rock art which was the very first "art." Rock art, such as the images created on the stone surfaces of the caves of Lascaux and Altimira, is the true origin of the canvas, paintbrush, and painting media. For there, within caverns deep in the earth, the first artists mixed animal fat, urine, and saliva with powdered minerals…

  14. Surface-enhanced Raman spectroscopy (SERS) for identifying traces of adenine in different mineral and rock samples

    Science.gov (United States)

    Lafuente, B.; Navarro, R.; Sansano, A.; Rull, F.

    2012-09-01

    The aim of this study is to analyze the potentials of SERS as a technique for in-situ identification of life traces in Mars surface explorations using the Raman instrument (RLS), payload of the ESA Mars mission Exomars. This preliminary study focused on detection of adenine on a variety of rocks soils samples using macro-SERS detection.

  15. Assessment of Rock-Eval Tmax Data in Bambra-2 Well of Barrow Sub-basin,North West Shelf of Australia: A Case Study of Contaminated Rock-Eval Data

    Institute of Scientific and Technical Information of China (English)

    He Sheng; Alex Kaiko; Mike Middleton; Jiang Chunqing

    2003-01-01

    The contamination of cuttings and side-wall core (SWC) samples in the Bambra-2 well by drilling-mud additives and natural hydrocarbons may cause Rock-Eval Tmax (℃) data to be suspect, and affect its utility in the assessment of thermal maturity. The Rock-Eval results of 284 cuttings samples,31 side-wall core samples and conventional core samples from the Jurassic-Cretaceous sedimentary sequences in the Bambra-2 well are presented in this paper. Significantly lower Tmax values from cuttings samples compared with Tmax values from conventional core samples and solvent extracted SWC samples,from the deeper and higher maturity interval, are thought to have been caused by contamination by diesel and other drilling-mud additives. The cuttings samples in the Barrow Group of Cretaceous may be contaminated by natural hydrocarbons, resulting their Tmax values to be 2-10 ℃ lower than a regularly increased Tmax trend from core samples. This study indicates that more reliable Rock-Eval Tmax data are obtained from the conventional core samples and solvent extracted SWC samples. This study also indicates that the Tmax values from some SWC samples were also affected by free hydrocarbons, due to the use of diesel as a mud additive as well.

  16. Enriching acid rock drainage related microbial communities from surface-deposited oil sands tailings.

    Science.gov (United States)

    Dean, Courtney; Xiao, Yeyuan; Roberts, Deborah J

    2016-10-01

    Little is known about the microbial communities native to surface-deposited pyritic oil sands tailings, an environment where acid rock drainage (ARD) could occur. The goal of this study was to enrich sulfur-oxidizing organisms from these tailings and determine whether different populations exist at pH levels 7, 4.5, and 2.5. Using growth-based methods provides model organisms for use in the future to predict potential activities and limitations of these organisms and to develop possible control methods. Thiosulfate-fed enrichment cultures were monitored for approximately 1 year. The results showed that the enrichments at pH 4.5 and 7 were established quicker than at pH 2.5. Different microbial community structures were found among the 3 pH environments. The sulfur-oxidizing microorganisms identified were most closely related to Halothiobacillus neapolitanus, Achromobacter spp., and Curtobacterium spp. While microorganisms related to Chitinophagaceae and Acidocella spp. were identified as the only possible iron-oxidizing and -reducing microbes. These results contribute to the general knowledge of the relatively understudied microbial communities that exist in pyritic oil sands tailings and indicate these communities may have a potential role in ARD generation, which may have implications for future tailings management.

  17. Estimated Altitude of the Consolidated Rock Surface Underlying Quaternary Sediments of the Wood River Valley aquifer system, South-Central Idaho

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This dataset is the estimated altitude of the consolidated rock surface underlying Quaternary sediment of the Wood River Valley aquifer system. This surface is...

  18. Distinct element modelling of fracture plan control in continuum and jointed rock mass in presplitting method of surface mining

    Institute of Scientific and Technical Information of China (English)

    Sharafisafa Mansour; Aliabadian Zeinab; Alizadeh Rezvan; Mortazavi Ali

    2014-01-01

    Controlled blasting techniques are used to control overbreak and to aid in the stability of the remaining rock formation. Presplitting is one of the most common methods which is used in many open pit mining and surface blast design. The purpose of presplitting is to form a fracture plane across which the radial cracks from the production blast cannot travel. The purpose of this study is to investigate of effect of pre-splitting on the generation of a smooth wall in continuum and jointed rock mass. The 2D distinct element code was used to simulate the presplitting in a rock slope. The blast load history as a function of time was applied to the inner wall of each blasthole. Important parameters that were considered in the analysis were stress tensor and fracturing pattern. The blast loading magnitude and blasthole spacing and jointing pattern were found to be very significant in the final results.

  19. The Questions of the Dynamics of Drilling Bit on the Surface of Well Bottom

    Science.gov (United States)

    Burievich, Toshov Javohir

    2016-06-01

    The purpose of this study was to investigate the dynamics of drilling bit on the well bottom as a function of their geometrical parameters. The frame of this method for this study includes former existed objective data on the unstable drilling devices as cantilever suspension. Research methods and calculation results are as follows: square coverage by tools blade working in different rotation regime; radius of the inscribed and circumscribed circle which leads to introduce and prospectively and solve problems on process optimization of mining rock at drilling the well bottom.

  20. Surface-groundwater interactions in hard rocks in Sardon Catchment of western Spain: an integrated modeling approach

    Science.gov (United States)

    Hassan, S.M. Tanvir; Lubczynski, Maciek W.; Niswonger, Richard G.; Zhongbo, Su

    2014-01-01

    The structural and hydrological complexity of hard rock systems (HRSs) affects dynamics of surface–groundwater interactions. These complexities are not well described or understood by hydrogeologists because simplified analyses typically are used to study HRSs. A transient, integrated hydrologic model (IHM) GSFLOW (Groundwater and Surface water FLOW) was calibrated and post-audited using 18 years of daily groundwater head and stream discharge data to evaluate the surface–groundwater interactions in semi-arid, ∼80 km2 granitic Sardon hilly catchment in Spain characterized by shallow water table conditions, relatively low storage, dense drainage networks and frequent, high intensity rainfall. The following hydrological observations for the Sardon Catchment, and more generally for HRSs were made: (i) significant bi-directional vertical flows occur between surface water and groundwater throughout the HRSs; (ii) relatively large groundwater recharge represents 16% of precipitation (P, 562 mm.y−1) and large groundwater exfiltration (∼11% of P) results in short groundwater flow paths due to a dense network of streams, low permeability and hilly topographic relief; deep, long groundwater flow paths constitute a smaller component of the water budget (∼1% of P); quite high groundwater evapotranspiration (∼5% of P and ∼7% of total evapotranspiration); low permeability and shallow soils are the main reasons for relatively large components of Hortonian flow and interflow (15% and 11% of P, respectively); (iii) the majority of drainage from the catchment leaves as surface water; (iv) declining 18 years trend (4.44 mm.y−1) of groundwater storage; and (v) large spatio-temporal variability of water fluxes. This IHM study of HRSs provides greater understanding of these relatively unknown hydrologic systems that are widespread throughout the world and are important for water resources in many regions.

  1. Estimation of groundwater flow directions and the tensor of hydraulic conductivity in crystalline massif rocks using information from surface structural geology and mining exploration boreholes

    Science.gov (United States)

    Florez, C.; Romero, M. A.; Ramirez, M. I.; Monsalve, G.

    2013-05-01

    In the elaboration of a hydrogeological conceptual model in regions of mining exploration where there is significant presence of crystalline massif rocks., the influence of physical and geometrical properties of rock discontinuities must be evaluated. We present the results of a structural analysis of rock discontinuities in a region of the Central Cordillera of Colombia (The upper and middle Bermellon Basin) in order to establish its hydrogeological characteristics for the improvement of the conceptual hydrogeological model for the region. The geology of the study area consists of schists with quartz and mica and porphyritic rocks, in a region of high slopes with a nearly 10 m thick weathered layer. The main objective of this research is to infer the preferential flow directions of groundwater and to estimate the tensor of potential hydraulic conductivity by using surface information and avoiding the use of wells and packer tests. The first step of our methodology is an analysis of drainage directions to detect patterns of structural controls in the run-off; after a field campaign of structural data recollection, where we compile information of strike, dip, continuity, spacing, roughness, aperture and frequency, we built equal area hydro-structural polar diagrams that indicate the potential directions for groundwater flow. These results are confronted with records of Rock Quality Designation (RQD) that have been systematically taken from several mining exploration boreholes in the area of study. By using all this information we estimate the potential tensor of hydraulic conductivity from a cubic law, obtaining the three principal directions with conductivities of the order of 10-5 and 10-6 m/s; the more conductive joint family has a NE strike with a nearly vertical dip.

  2. Exploration and Practice of Rock Salt Brine Well Associated with Gas%卤井盐岩伴生气治理探索与实践

    Institute of Scientific and Technical Information of China (English)

    高莉霞; 刘川

    2014-01-01

    根据我公司不同时期对卤井盐岩伴生气治理的探索实践,从卤井盐岩伴生气治理的必要性出发,浅析废气处理装置在伴生有尚且不具备综合利用价值的硫化氢、天然气等可燃气体的盐岩矿山应用的可行性、运行原理及成效分析。%Based on the practice and exploration on the management of rock salt birne well associated gas by our company and starting from the necessity of the treatment of rock salt brine well associated gas, thsi paper analyzes the feasibility, operating principal and effectiveness of using waste gas treatment plant in the rock salt mine associated with hydrogen sulfide ,natural gas and other combustible gases which have no comprehensive utilization value.

  3. Surface morphology and dynamic of debris-covered and rock glaciers in the Tröllaskagi Peninsula (northern Iceland).

    Science.gov (United States)

    Tanarro, Luis M.; Palacios, David; Andres, Nuria; Fernández, Jose M.; Zamorano, Jose J.

    2017-04-01

    been displaced by 2.8 m, indicating a velocity lower than 0.20 m yr-1. The limited advance of the crests seems to be related to a process of surface lowering, as they show a decrease of their average altitude by 0.6 m (0.04 m yr-1). The results obtained at the Fremri-Grjótárdalur rock glacier show that the horizontal displacement of blocks is very low, less than 0.2 m yr-1, with a decrease in their average altitude by 0.37 m. The low rates of block displacement and monitored features, as well as the important process of surface lowering observed in these landforms, may indicate that widespread melting is the most important activity occurring at the debris-covered and rock glaciers in Tröllaskagui. Beside the slow movement at the Hóladalsjökull debris-covered glacier and the lack of movement at Fremri-Grjótárdalur, no changes have occurred in their surface morphology in the last 54 years, except for the formation of some depressions due to collapse in the former. Research funded by Deglaciation project (CGL2015-65813-R), Government of Spain References Andrés, N., Tanarro, L.M., Fernández, J.M. y Palacios, D. 2016. The origin of glacial alpine landscape in Tröllaskagi Peninsula (North Iceland). Cuadernos de investigación Geográfica, 42 (2): 341-368.

  4. Spatial distribution of surface rock fragment on hillslopes in a small catchment in wind-water erosion crisscross region of the Loess Plateau

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The cover and size distributions of surface rock fragment in hillslopes were investigated by using digital photographing and treating technique in a small catchment in wind-water erosion crisscross region of the Loess Plateau. The results indicated that the maximal cover of rock fragment was pre-sented at mid-position in steep hillslope. Rock fragment presented a general decreasing-trend along the hillslope in gentle hillslope. Rock fragment cover was positively related to gradient, rock fragment size decreased generally along the hillslope, and the size reduced with the gradient. The mean size of rock fragment was at a range of 6―20 mm in the steep hillslope, rock fragment size > 50 mm was rarely presented. The covers of rock fragment at different positions were markedly related to the quantities of rock fragment < 40 mm. The area of rock fragment of 2―50 mm accounted for 60% or more of the total area, dominating the distribution of rock fragment in the hillslopes.

  5. Infiltration of pesticides in surface water into nearby drinking water supply wells

    DEFF Research Database (Denmark)

    Malaguerra, Flavio; Albrechtsen, Hans-Jørgen; Binning, Philip John

    Drinking water wells are often placed near streams because streams often overly permeable sediments and the water table is near the surface in valleys, and so pumping costs are reduced. The lowering of the water table by pumping wells can reverse the natural flow from the groundwater to the stream......, inducing infiltration of surface water to groundwater and consequently to the drinking water well. Many attenuation processes can take place in the riparian zone, mainly due to mixing, biodegradation and sorption. However, if the water travel time from the surface water to the pumping well is too short......, or if the compounds are poorly degradable, contaminants can reach the drinking water well at high concentrations, jeopardizing drinking water quality. Here we developed a reactive transport model to evaluate the risk of contamination of drinking water wells by surface water pollution. The model was validated using...

  6. A highly stable nonbiofouling surface with well-packed grafted zwitterionic polysulfobetaine for plasma protein repulsion.

    Science.gov (United States)

    Chang, Yung; Liao, Shih-Chieh; Higuchi, Akon; Ruaan, Ruoh-Chyu; Chu, Chih-Wei; Chen, Wen-Yih

    2008-05-20

    An ideal nonbiofouling surface for biomedical applications requires both high-efficient antifouling characteristics in relation to biological components and long-term material stability from biological systems. In this study we demonstrate the performance and stability of an antifouling surface with grafted zwitterionic sulfobetaine methacrylate (SBMA). The SBMA was grafted from a bromide-covered gold surface via surface-initiated atom transfer radical polymerization to form well-packed polymer brushes. Plasma protein adsorption on poly(sulfobetaine methacrylate) (polySBMA) grafted surfaces was measured with a surface plasmon resonance sensor. It is revealed that an excellent stable nonbiofouling surface with grafted polySBMA can be performed with a cycling test of the adsorption of three model proteins in a wide range of various salt types, buffer compositions, solution pH levels, and temperatures. This work also demonstrates the adsorption of plasma proteins and the adhesion of platelets from human blood plasma on the polySBMA grafted surface. It was found that the polySBMA grafted surface effectively reduces the plasma protein adsorption from platelet-poor plasma solution to a level superior to that of adsorption on a surface terminated with tetra(ethylene glycol). The adhesion and activation of platelets from platelet-rich plasma solution were not observed on the polySBMA grafted surface. This work further concludes that a surface with good hemocompatibility can be achieved by the well-packed surface-grafted polySBMA brushes.

  7. Distributed snow and rock temperature modelling in steep rock walls using Alpine3D

    Science.gov (United States)

    Haberkorn, Anna; Wever, Nander; Hoelzle, Martin; Phillips, Marcia; Kenner, Robert; Bavay, Mathias; Lehning, Michael

    2017-02-01

    In this study we modelled the influence of the spatially and temporally heterogeneous snow cover on the surface energy balance and thus on rock temperatures in two rugged, steep rock walls on the Gemsstock ridge in the central Swiss Alps. The heterogeneous snow depth distribution in the rock walls was introduced to the distributed, process-based energy balance model Alpine3D with a precipitation scaling method based on snow depth data measured by terrestrial laser scanning. The influence of the snow cover on rock temperatures was investigated by comparing a snow-covered model scenario (precipitation input provided by precipitation scaling) with a snow-free (zero precipitation input) one. Model uncertainties are discussed and evaluated at both the point and spatial scales against 22 near-surface rock temperature measurements and high-resolution snow depth data from winter terrestrial laser scans.In the rough rock walls, the heterogeneously distributed snow cover was moderately well reproduced by Alpine3D with mean absolute errors ranging between 0.31 and 0.81 m. However, snow cover duration was reproduced well and, consequently, near-surface rock temperatures were modelled convincingly. Uncertainties in rock temperature modelling were found to be around 1.6 °C. Errors in snow cover modelling and hence in rock temperature simulations are explained by inadequate snow settlement due to linear precipitation scaling, missing lateral heat fluxes in the rock, and by errors caused by interpolation of shortwave radiation, wind and air temperature into the rock walls.Mean annual near-surface rock temperature increases were both measured and modelled in the steep rock walls as a consequence of a thick, long-lasting snow cover. Rock temperatures were 1.3-2.5 °C higher in the shaded and sunny rock walls, while comparing snow-covered to snow-free simulations. This helps to assess the potential error made in ground temperature modelling when neglecting snow in steep bedrock.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-08-18

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

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

    Science.gov (United States)

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

    2015-08-18

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

  10. The Research into the Quality of Rock Surfaces Obtained by Abrasive Water Jet Cutting

    Science.gov (United States)

    Młynarczuk, Mariusz; Skiba, Marta; Sitek, Libor; Hlaváček, Petr; Kožušníková, Alena

    2014-12-01

    In recent years, water jet cutting technology has been being used more and more often, in various domains of human activity. Its numerous applications include cutting different materials - among them, rock materials. The present paper discusses the results of the research that aimed at determining - in a quantitative manner - the way in which the water jet cutting parameters (such as the traverse speed of the head, and the distance between the high-pressure inlet of the water jet and the cut material) influence the quality of the processed surface. Additionally, the impact of these parameters on the surface of various materials was investigated. The materials used were three granites differing with respect to the size of grains. In the course of the research, the standard parameters defined by the ISO norms were analyzed. It was also proposed that variograms be used to analyze the quality of the cut surface. Technologia cięcia strumieniem wodnym staje się w ostatnich latach coraz intensywniej wykorzystywana w różnych dziedzinach działalności człowieka. Jest ona wykorzystywana do obróbki różnorodnych materiałów, również materiałów skalnych. W ramach badań analizowano trzy granity różniące się m.in. wielkościami ziarn, które były przecinane przy różnych prędkościach przesuwu głowicy z wlotem strumienia wodnego. Analizowano standardowe parametry zdefiniowane w normach ISO jak również zaproponowano wykorzystanie wariogramów do analizy jakości wyciętej powierzchni. W pracy opisano w sposób ilościowy zmiany jakości powierzchni skał ciętych strumieniem wodnym ze ścierniwem w zależności od prędkości przesuwu głowicy, jak również w zależności od odległości przecinanego fragmentu powierzchni od wlotu strumienia wodnego do materiału. Wyniki uzyskane w pomiarach wskazują też na wpływ wielkości uziarnienia skały na jakość otrzymanej powierzchni. Jest to szczególnie widoczne dla najmniej optymalnych parametrów ci

  11. Mineralogical controls on NMR rock surface relaxivity: A case study of the Fontainebleau Sandstone

    Science.gov (United States)

    Livo, Kurt

    Pore size distribution is derived from nuclear magnetic resonance, but is scaled by surface relaxivity. While nuclear magnetic resonance studies generally focus on the difficulty of determining pore size distribution in unconventional shale reservoirs, there is a lack of discussion concerning pure quartz sandstones. Long surface relaxivity causes complications analyzing nuclear magnetic resonance data for pore size distribution determination. Currently, I am unaware of research that addresses the complicated pore size distribution determination in long relaxing, pure sandstone formations, which is essential to accurate downhole petrophysical modeling. The Fontainebleau sandstone is well known for its homogenous mineralogical makeup and wide range of porosity and permeability. The Hibernia sandstone exhibits a similar mineralogy and is characterized by a similar and porosity-permeability range to the Fontainebleau sandstones, but with a significantly higher portion of clay minerals (1-6%). I present systematic petrophysical properties such as porosity, pore size distribution from nuclear magnetic resonance transverse relaxation times, permeability, and volumetric magnetic susceptibility to aide in characterization of the Fontainebleau sandstone. Analysis of collected nuclear magnetic resonance data is then compared to other petrophysical studies from literature such as helium porosity and permeability, magnetic susceptibility, and electrical conductivity. I find that the lack of impurities on the grain surfaces of pure quartz samples imparts a lower surface relaxivity as compared to clay containing sandstones and makes nuclear magnetic resonance analysis more complex. Thus, inverted nuclear magnetic resonance data from cleaner outcrop samples incorrectly models pore size distribution without accounting for wider surface relaxivity variation and is improperly used when characterizing the Fontainebleau sandstone. This is further supported by evidence from less

  12. Defining X-Ray Diffraction Parameters for the Design and Operation of a Planetary-Surface Rock Analyzer

    Science.gov (United States)

    Metzger, Ellen P.; Keaten, Rendy; Marshall, John R.; Kojiro, Dan

    1996-01-01

    Our joint research effort was aimed at developing techniques for X-ray diffractometry that was being investigated by NASA as possible flight instrumentation for the exploration of Mars. SJSU would provide the use of in-house X-ray facilities for calibration of the instrumentation , and would provide technical expertise regarding interpretation of data acquired during both laboratory testing, and during field testing of instruments on the Marsokhod rover at Ames. Accomplishments are: (1) quantification of X-ray signals from rock surfaces using San Jose State University (SJSU) diffractometer; (2) development of criteria for fingerprinting rock samples using pattern recognition of diffraction spectra, and augmentation of diffraction data with X-ray fluorescence information; (3) calibration of NASA instrumentation using SJSU-generator data; and (4) assistance in the development, lab testing, and field deployment of the NASA instrument on the Russian Marsokhod roving vehicle designed for martian exploration.

  13. Metagenomes of Microbial Communities in Arsenic- and Pathogen-Contaminated Well and Surface Water from Bangladesh

    OpenAIRE

    Layton, Alice C.; Chauhan, Archana; Williams, Daniel E.; Mailloux, Brian; Knappett, Peter S. K.; Ferguson, Andrew S.; McKay, Larry D.; Alam, M. Jahangir; Matin Ahmed, Kazi; van Geen, Alexander; Sayler, Gary S.

    2014-01-01

    The contamination of drinking water from both arsenic and microbial pathogens occurs in Bangladesh. A general metagenomic survey of well water and surface water provided information on the types of pathogens present and may help elucidate arsenic metabolic pathways and potential assay targets for monitoring surface-to-ground water pathogen transport.

  14. Physisorption on flat surfaces and inside square wells: a transfer matrix study

    Science.gov (United States)

    Cheng, E.; Banavar, J. R.; Cole, M. W.; Toigo, F.

    1992-01-01

    Calculations are performed with the transfer matrix method to predict adsorption on a flat surface and on a pore-like well on the surface. In the flat case, temperature-dependent deviation from the Frenkel-Halsey-Hill theory is seen. For numerical reasons the calculations are done for a two-dimensional "world".

  15. Thermally induced stresses in boulders on airless body surfaces, and implications for rock breakdown

    Science.gov (United States)

    Molaro, J. L.; Byrne, S.; Le, J.-L.

    2017-09-01

    This work investigates the macroscopic thermomechanical behavior of lunar boulders by modeling their response to diurnal thermal forcing. Our results reveal a bimodal, spatiotemporally-complex stress response. During sunrise, stresses occur in the boulders' interiors that are associated with large-scale temperature gradients developed due to overnight cooling. During sunset, stresses occur at the boulders' exteriors due to the cooling and contraction of the surface. Both kinds of stresses are on the order of 10 MPa in 1 m boulders and decrease for smaller diameters, suggesting that larger boulders break down more quickly. Boulders ≤ 30 cm exhibit a weak response to thermal forcing, suggesting a threshold below which crack propagation may not occur. Boulders of any size buried by regolith are shielded from thermal breakdown. As boulders increase in size (>1 m), stresses increase to several 10 s of MPa as the behavior of their surfaces approaches that of an infinite halfspace. As the thermal wave loses contact with the boulder interior, stresses become limited to the near-surface. This suggests that the survival time of a boulder is not only controlled by the amplitude of induced stress, but also by its diameter as compared to the diurnal skin depth. While stresses on the order of 10 MPa are enough to drive crack propagation in terrestrial environments, crack propagation rates in vacuum are not well constrained. We explore the relationship between boulder size, stress, and the direction of crack propagation, and discuss the implications for the relative breakdown rates and estimated lifetimes of boulders on airless body surfaces.

  16. Fermi surface and quantum well states of V(110) films on W(110)

    Energy Technology Data Exchange (ETDEWEB)

    Krupin, Oleg [MS 6-2100, Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Rotenberg, Eli [MS 6-2100, Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Kevan, S D [Department of Physics, University of Oregon, Eugene, OR 97403 (United States)

    2007-09-05

    Using angle-resolved photoemission spectroscopy, we have measured the Fermi surface of V(110) films epitaxially grown on a W(110) substrate. We compare our results for thicker films to existing calculations and measurements for bulk vanadium and find generally very good agreement. For thinner films, we observe and analyse a diverse array of quantum well states that split and distort the Fermi surface segments. We have searched unsuccessfully for a thickness-induced topological transition associated with contact between the zone-centre jungle gym and zone-boundary hole ellipsoid Fermi surface segments. We also find no evidence for ferromagnetic splitting of any bands on this surface.

  17. The Rock Cycle

    Science.gov (United States)

    Singh, Raman J.; Bushee, Jonathan

    1977-01-01

    Presents a rock cycle diagram suitable for use at the secondary or introductory college levels which separates rocks formed on and below the surface, includes organic materials, and separates products from processes. (SL)

  18. A simplified fracture network model for studying the efficiency of a single well semi open loop heat exchanger in fractured crystalline rock

    Science.gov (United States)

    de La Bernardie, Jérôme; de Dreuzy, Jean-Raynald; Bour, Olivier; Thierion, Charlotte; Ausseur, Jean-Yves; Lesuer, Hervé; Le Borgne, Tanguy

    2016-04-01

    Geothermal energy is a renewable energy source particularly attractive due to associated low greenhouse gas emission rates. Crystalline rocks are in general considered of poor interest for geothermal applications at shallow depths (energy storage at these shallow depths is still remaining very challenging because of the complexity of fractured media. The purpose of this study is to test the possibility of efficient thermal energy storage in shallow fractured rocks with a single well semi open loop heat exchanger (standing column well). For doing so, a simplified numerical model of fractured media is considered with few fractures. Here we present the different steps for building the model and for achieving the sensitivity analysis. First, an analytical and dimensional study on the equations has been achieved to highlight the main parameters that control the optimization of the system. In a second step, multiphysics software COMSOL was used to achieve numerical simulations in a very simplified model of fractured media. The objective was to test the efficiency of such a system to store and recover thermal energy depending on i) the few parameters controlling fracture network geometry (size and number of fractures) and ii) the frequency of cycles used to store and recover thermal energy. The results have then been compared to reference shallow geothermal systems already set up for porous media. Through this study, relationships between structure, heat exchanges and storage may be highlighted.

  19. Fractal Characteristics of Rock Fracture Surface under Triaxial Compression after High Temperature

    Directory of Open Access Journals (Sweden)

    X. L. Xu

    2016-01-01

    Full Text Available Scanning Electron Microscopy (SEM test on 30 pieces of fractured granite has been researched by using S250MK III SEM under triaxial compression of different temperature (25~1000°C and confining pressure (0~40 MPa. Research results show that (1 the change of fractal dimension (FD of rock fracture with temperature is closely related to confining pressure, which can be divided into two categories. In the first category, when confining pressure is in 0~30 MPa, FD fits cubic polynomial fitting curve with temperature, reaching the maximum at 600°C. In the second category, when confining pressure is in 30~40 MPa, FD has volatility with temperature. (2 The FD of rock fracture varies with confining pressure and is also closely related to the temperature, which can be divided into three categories. In the first category, FD has volatility with confining pressure at 25°C, 400°C, and 800°C. In the second category, it increases exponentially at 200°C and 1000°C. In the third category, it decreases exponentially at 600°C. (3 It is found that 600°C is the critical temperature and 30 MPa is the critical confining pressure of granite. The rock transfers from brittle to plastic phase transition when temperature exceeds 600°C and confining pressure exceeds 30 MPa.

  20. Infiltration of pesticides in surface water into nearby drinking water supply wells

    Science.gov (United States)

    Malaguerra, F.; Albrechtsen, H.; Binning, P. J.

    2010-12-01

    Drinking water wells are often placed near streams because streams often overly permeable sediments and the water table is near the surface in valleys, and so pumping costs are reduced. The lowering of the water table by pumping wells can reverse the natural flow from the groundwater to the stream, inducing infiltration of surface water to groundwater and consequently to the drinking water well. Many attenuation processes can take place in the riparian zone, mainly due to mixing, biodegradation and sorption. However, if the water travel time from the surface water to the pumping well is too short, or if the compounds are poorly degradable, contaminants can reach the drinking water well at high concentrations, jeopardizing drinking water quality. Here we developed a reactive transport model to evaluate the risk of contamination of drinking water wells by surface water pollution. The model was validated using data of a tracer experiment in a riparian zone. Three compounds were considered: an older pesticide MCPP (Mecoprop) which is mobile and persistent, glyphosate (Roundup), a new biodegradable and strongly sorbed pesticide, and its degradation product AMPA. Global sensitivity analysis using the method of Morris was employed to identify the dominant model parameters. Results showed that the presence of an aquitard and its characteristics (degree of fracturing and thickness), pollutant properties and well depth are the crucial factors affecting the risk of drinking water well contamination from surface water. Global sensitivity analysis results were compared with rank correlation statistics between pesticide concentrations and geological parameters derived from a comprehensive database of Danish drinking water wells. Aquitard thickness and well depth are the most critical parameters in both the model and observed data.

  1. Enhanced luminescence of near-surface quantum wells passivated in situ by InP

    Energy Technology Data Exchange (ETDEWEB)

    Lipsanen, H.; Sopanen, M.; Taskinen, M.; Tulkki, J. [Helsinki Univ. of Technology, Espoo (Finland). Optoelectronics Lab.; Ahopelto, J. [VTT Electronics, Espoo (Finland)

    1996-12-31

    The authors have studied the optical properties of MOVPE grown Al{sub x}Ga{sub 1{minus}x}As/GaAs structures passivated by in situ deposition of InP on the surface. One monolayer of InP was used for the passivation. The surface recombination was studied by photoluminescence measurements of near-surface Al{sub 0.22}Ga{sub 0.78}As/GaAs quantum wells. The luminescence intensity of the passivated samples increased by about five orders of magnitude for quantum wells located at less than 5 nm from the surface as compared to unpassivated samples. Furthermore, the authors observed a blueshift of 15 meV for a passivated surface quantum well. The effect of the thin InP layer on the Fermi level pinning on the surface was studied by photoreflectance of a surface-i-n{sup +} sample. The pinning position was reduced by 0.3 eV from the mid-bandgap value.

  2. Influence of a single lightning on the intensity of an air electric field and acoustic emission of near surface rocks

    Directory of Open Access Journals (Sweden)

    S. E. Smirnov

    2012-06-01

    Full Text Available The effect of a single lightning discharge on electric field intensity in the near ground atmosphere was investigated. The effect appeared as a sharp fall of electric field potential gradient from 80 V m−1 up to −21 V m−1. The process of intensity recovery is described by flat capacitor model with characteristic time of recovery of 17 c. Simultaneously with electric field, the acoustic emission response in the near surface rocks on lightning discharge was registered in the frequency range of 6.5–11 kHz.

  3. Geochemistry, mineralogy, and petrology of boninitic and komatiitic rocks on the mercurian surface: Insights into the mercurian mantle

    Science.gov (United States)

    Vander Kaaden, Kathleen E.; McCubbin, Francis M.; Nittler, Larry R.; Peplowski, Patrick N.; Weider, Shoshana Z.; Frank, Elizabeth A.; McCoy, Timothy J.

    2017-03-01

    Orbital data from the MESSENGER mission to Mercury have facilitated a new view of the planet's structure, chemical makeup, and diverse surface, and have confirmed Mercury's status as a geochemical endmember among the terrestrial planets. In this work, the most recent results from MESSENGER's X-Ray Spectrometer, Gamma-Ray Spectrometer, and Neutron Spectrometer have been used to identify nine distinct geochemical regions on Mercury. Using a variation on the classical CIPW normative mineralogy calculation, elemental composition data is used to constrain the potential mineralogy of Mercury's surface; the calculated silicate mineralogy is dominated by plagioclase, pyroxene (both orthopyroxene and clinopyroxene), and olivine, with lesser amounts of quartz. The range in surface compositions indicate that the rocks on the surface of Mercury are diverse and vary from komatiitic to boninitic. The high abundance of alkalis on Mercury's surface results in several of the nine regions being classified as alkali-rich komatiites and/or boninites. In addition, Mercury's surface terranes span a wide range of SiO2 values that encompass crustal compositions that are more silica-rich than geochemical terranes on the Moon, Mars, and Vesta, but the range is similar to that of Earth. Although the composition of Mercury's surface appears to be chemically evolved, the high SiO2 content is a primitive feature and a direct result of the planet's low oxygen fugacity.

  4. Numerical assessment of ASR recharge using small-diameter wells and surface basins

    Science.gov (United States)

    Händel, Falk; Liu, Gaisheng; Dietrich, Peter; Liedl, Rudolf; Butler, James J.

    2014-09-01

    Aquifer storage and recovery (ASR) methods are increasingly used to overcome the temporal imbalance between water demand and availability. Common ASR recharge methods utilize large-diameter injection wells or surface infiltration basins and trenches, and can be costly to implement. A new low-cost ASR recharge method is currently being developed. This approach is based on recharge via gravity in small-diameter wells installed with direct-push (DP) technology. Numerical modeling is used here to assess the potential of this new approach under conditions commonly faced in field settings. The primary objective is to investigate if a battery of small-diameter DP wells can serve as a viable alternative to a surface basin under typical field conditions, while the secondary objective is to assess which subsurface parameters have the greatest control on DP well performance. Simulation results indicate that gravity recharge via small-diameter wells appears to have a distinct advantage over recharge via surface infiltration basins. For example, two 0.05-m shallow vadose-zone wells with 9-m screens can recharge water at a greater rate than a 60 m2 basin. Also, results reveal that, contrary to an infiltration basin, the recharge rate in a DP well has a much stronger dependence on the horizontal component of hydraulic conductivity than on the vertical component. Moreover, near-surface layers of low hydraulic conductivity, which can significantly reduce the recharge capacity of a surface basin, have a relatively small impact on the recharge capacity of a well as long as a significant portion of the well screen is installed below those layers. Given that installation and operation costs can be low in comparison to common ASR recharge methods, this new approach appears to have great potential for recharging good quality water in shallow unconsolidated aquifers. A field investigation has recently been initiated to follow up the findings of this simulation assessment.

  5. Seismic Technology Adapted to Analyzing and Developing Geothermal Systems Below Surface-Exposed High-Velocity Rocks Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Hardage, Bob A. [Univ. of Texas, Austin, TX (United States). Bureau of Economic Geology; DeAngelo, Michael V. [Univ. of Texas, Austin, TX (United States). Bureau of Economic Geology; Ermolaeva, Elena [Univ. of Texas, Austin, TX (United States). Bureau of Economic Geology; Hardage, Bob A. [Univ. of Texas, Austin, TX (United States). Bureau of Economic Geology; Remington, Randy [Univ. of Texas, Austin, TX (United States). Bureau of Economic Geology; Sava, Diana [Univ. of Texas, Austin, TX (United States). Bureau of Economic Geology; Wagner, Donald [Univ. of Texas, Austin, TX (United States). Bureau of Economic Geology; Wei, Shuijion [Univ. of Texas, Austin, TX (United States). Bureau of Economic Geology

    2013-02-01

    The objective of our research was to develop and demonstrate seismic data-acquisition and data-processing technologies that allow geothermal prospects below high-velocity rock outcrops to be evaluated. To do this, we acquired a 3-component seismic test line across an area of exposed high-velocity rocks in Brewster County, Texas, where there is high heat flow and surface conditions mimic those found at numerous geothermal prospects. Seismic contractors have not succeeded in creating good-quality seismic data in this area for companies who have acquired data for oil and gas exploitation purposes. Our test profile traversed an area where high-velocity rocks and low-velocity sediment were exposed on the surface in alternating patterns that repeated along the test line. We verified that these surface conditions cause non-ending reverberations of Love waves, Rayleigh waves, and shallow critical refractions to travel across the earth surface between the boundaries of the fast-velocity and slow-velocity material exposed on the surface. These reverberating surface waves form the high level of noise in this area that does not allow reflections from deep interfaces to be seen and utilized. Our data-acquisition method of deploying a box array of closely spaced geophones allowed us to recognize and evaluate these surface-wave noise modes regardless of the azimuth direction to the surface anomaly that backscattered the waves and caused them to return to the test-line profile. With this knowledge of the surface-wave noise, we were able to process these test-line data to create P-P and SH-SH images that were superior to those produced by a skilled seismic data-processing contractor. Compared to the P-P data acquired along the test line, the SH-SH data provided a better detection of faults and could be used to trace these faults upward to the boundaries of exposed surface rocks. We expanded our comparison of the relative value of S-wave and P-wave seismic data for geothermal

  6. Hydraulic characterization of volcanic rocks in Pahute Mesa using an integrated analysis of 16 multiple-well aquifer tests, Nevada National Security Site, 2009–14

    Science.gov (United States)

    Garcia, C. Amanda; Jackson, Tracie R.; Halford, Keith J.; Sweetkind, Donald S.; Damar, Nancy A.; Fenelon, Joseph M.; Reiner, Steven R.

    2017-01-20

    An improved understanding of groundwater flow and radionuclide migration downgradient from underground nuclear-testing areas at Pahute Mesa, Nevada National Security Site, requires accurate subsurface hydraulic characterization. To improve conceptual models of flow and transport in the complex hydrogeologic system beneath Pahute Mesa, the U.S. Geological Survey characterized bulk hydraulic properties of volcanic rocks using an integrated analysis of 16 multiple-well aquifer tests. Single-well aquifer-test analyses provided transmissivity estimates at pumped wells. Transmissivity estimates ranged from less than 1 to about 100,000 square feet per day in Pahute Mesa and the vicinity. Drawdown from multiple-well aquifer testing was estimated and distinguished from natural fluctuations in more than 200 pumping and observation wells using analytical water-level models. Drawdown was detected at distances greater than 3 miles from pumping wells and propagated across hydrostratigraphic units and major structures, indicating that neither faults nor structural blocks noticeably impede or divert groundwater flow in the study area.Consistent hydraulic properties were estimated by simultaneously interpreting drawdown from the 16 multiple-well aquifer tests with an integrated groundwater-flow model composed of 11 well-site models—1 for each aquifer test site. Hydraulic properties were distributed across volcanic rocks with the Phase II Pahute Mesa-Oasis Valley Hydrostratigraphic Framework Model. Estimated hydraulic-conductivity distributions spanned more than two orders of magnitude in hydrostratigraphic units. Overlapping hydraulic conductivity ranges among units indicated that most Phase II Hydrostratigraphic Framework Model units were not hydraulically distinct. Simulated total transmissivity ranged from 1,600 to 68,000 square feet per day for all pumping wells analyzed. High-transmissivity zones exceeding 10,000 square feet per day exist near caldera margins and extend

  7. Roughnecks, rock bits and rigs : the evolution of oil well drilling technology in Alberta, 1883-1970

    Energy Technology Data Exchange (ETDEWEB)

    Gow, A.

    2005-07-01

    This book provides a comprehensive review of the evolving technologies related to oil and gas exploration in the province of Alberta. Oil well drilling technology evolved significantly during the era of conventional oil exploration in the province, from 1883 through 1970. Technologies such as drill bits and power sources were developed largely through trial and error to meet the specific needs of individuals working in the oilfield. The competence and resolve to innovate by drill crews was told through accounts of evolution in drilling processes and equipment, along with personal accounts of those who worked on the rigs. The technology of the oilfield was placed into context with a summary of the history and geology of oil and gas in Alberta. The book also presents a considerate view of events in relation to those who invested in the industry, carried out research drilling and serviced the exploration industry. The first part of the book provides the background to the oil and gas industry. Part 2 examines the earliest technology, the standard cable tool drilling rig, the combination rig and some associated developments in drilling. The third part focuses on the rotary drilling rig and the final part outlines the types of challenges faced by the drillers and the hazards of working on Alberta's rigs. refs., tabs., figs.

  8. Surface exposure dating with cosmogenic 10Be of Late Holocene rock avalanches onto glaciers in the Mont Blanc massif, Italy

    Science.gov (United States)

    Deline, Philip; Akçar, Naki; Ivy-Ochs, Susan; Kubik, Peter W.

    2013-04-01

    Rock avalanching represents a potential high risk for growing infrastructure and people living in high mountain areas. This hazardous process is due to steep slopes, high relief, intensive rock fracturing, seismicity, paraglacial control, periglacial climatic conditions and the presence and interaction of snow, glaciers, and permafrost. The timing of rock avalanche recurrence intervals and the recognition of their spatial extension are essential. Very steep and elevated slopes on the Italian flank of the Mont Blanc massif are prone to rock avalanches (RAs) which travel onto glaciers. Whereas small RAs occurred in the Glacier du Miage basin during the 20th Century (the latest in July 2012), large RAs (volume > 1 M m3) travelled repeatedly onto Glaciers de Triolet, Frébouge, and la Brenva during the late Holocene The nature of the granitic deposit which largely overlaps the bottom of the upper Val Ferret over 2 km has been discussed since the 19th century. This extensive deposit was attributed to either glacial, or a September 12th 1717 AD rock avalanche, or a complex mixture of glacial, earlier RA and 1717 RA origin. Surface exposure dating of 16 boulders of the deposit shows that the 1717 RA, covering the whole upper Ferret valley floor, was one of the largest late Holocene RAs of the Alps, with a rock volume of 10-15 M m3 and a likely similar volume of glacier ice travelling more than 7 km downvalley. Two main RA deposits are lying downstream of the Glacier de Frébouge: a sheet of granite boulders with an open-work structure covers the south side of the Val Ferret, which ran > 100 m up the opposite metasedimentary side of the valley; a smaller RA deposit is located at the south and east margins of the large Frébouge polygenic fan. Surface exposure dating of 7 granite boulders of these deposits could in particular confirm whether the larger RA occurred sometime between 991 and 1154 AD, as suggested by a radiocarbon-dated piece of wood. Large RAs (volume > 2 M m3

  9. Geochemistry of surface water in alpine catchments in central Colorado, USA: Resolving host-rock effects at different spatial scales

    Science.gov (United States)

    Wanty, R.B.; Verplanck, P.L.; San, Juan C.A.; Church, S.E.; Schmidt, T.S.; Fey, D.L.; deWitt, E.H.; Klein, T.L.

    2009-01-01

    The US Geological Survey is conducting a study of surface-water quality in the Rocky Mountains of central Colorado, an area of approximately 55,000 km2. Using new and existing geologic maps, the more than 200 rock formations represented in the area were arranged into 17 groups based on lithologic similarity. The dominant regional geologic feature affecting water quality in central Colorado is the Colorado mineral belt (CMB), a NE-trending zone hosting many polymetallic vein or replacement deposits, and porphyry Mo deposits, many of which have been mined historically. The influence of the CMB is seen in lower surface-water pH (100 mg/L) and chalcophile metals such as Cu (>10 ??g/L), Zn (>100 ??g/L), and Cd (>1 ??g/L) relative to surface water outside the CMB. Not all streams within the CMB have been affected by mineralization, as there are numerous catchments within the CMB that have no mineralization or alteration exposed at the surface. At the regional-scale, and away from sites affected by mineralization, hydrothermal alteration, or mining, the effects of lithology on water quality can be distinguished using geochemical reaction modeling and principal components analysis. At local scales (100 s of km2), effects of individual rock units on water chemistry are subtle but discernible, as shown by variations in concentrations of major lithophile elements or ratios between them. These results demonstrate the usefulness of regional geochemical sampling of surface waters and process-based interpretations incorporating geologic and geochemical understanding to establish geochemical baselines.

  10. The viscous surface-internal wave problem: global well-posedness and decay

    CERN Document Server

    Wang, Yanjin; Kim, Chanwoo

    2011-01-01

    We consider the free boundary problem for two layers of immiscible, viscous, incompressible fluid in a uniform gravitational field, lying above a general rigid bottom in a three-dimensional horizontally periodic setting. We establish the global well-posedness of the problem both with and without surface tension. We prove that without surface tension the solution decays to the equilibrium state at an almost exponential rate; with surface tension, we show that the solution decays at an exponential rate. Our results include the case in which a heavier fluid lies above a lighter one, provided that the surface tension at the free internal interface is above a critical value, which we identify. This means that sufficiently large surface tension stabilizes the Rayleigh-Taylor instability in the nonlinear setting. As a part of our analysis, we establish elliptic estimates for the two-phase stationary Stokes problem.

  11. Surface motion of active rock glaciers in the Sierra Nevada, California, USA: inventory and a case study using InSAR

    Directory of Open Access Journals (Sweden)

    L. Liu

    2013-07-01

    Full Text Available Despite the abundance of rock glaciers in the Sierra Nevada of California, USA, few efforts have been made to measure their surface flow. Here we use the interferometric synthetic aperture radar (InSAR technique to compile a benchmark inventory describing the kinematic state of 59 active rock glaciers in this region. In the late summer of 2007, these rock glaciers moved at speeds that range from 14 cm yr−1 to 87 cm yr−1, with a regional mean value of 53 cm yr−1. Our inventory reveals a spatial difference: rock glaciers in the southern Sierra Nevada moved faster than the ones in the central Sierra Nevada. In addition to the regional mapping, we also conduct a case study to measure the surface flow of the Mount Gibbs rock glacier in fine spatial and temporal detail. The InSAR measurements over this target reveal (1 that the spatial pattern of flow is correlated with surface geomorphic features and (2 a significant seasonal variation of flow speed whose peak value was 48 cm yr−1in the fall of 2007, more than twice the minimum value observed in the spring of 2008. The seasonal variation lagged air temperatures by three months. Our finding on the seasonal variation of surface speed reinforces the importance of a long time series with high temporal sampling rates to detect possible long-term changes of rock glacier kinematics in a warming climate.

  12. Fast Drilling Technique through Igneous Rocks in Well Hashan 3%哈山3井火成岩地层快速钻井技术

    Institute of Scientific and Technical Information of China (English)

    马凤清

    2014-01-01

    A drilling technique combining PDC bit and torsional impact tool has been developed and applied in drilling through the igneous rocks of Junggar Basin w hich solves the technical difficulties such as high hard-ness ,poor drillability and serious well deviation ,etc in drilling through igneous rock formation .In view of the li-thologic characteristics and technical difficulties of igneous rocks ,PK6245MJD PDC bit for φ311.1 mm diame-ter borehole with strong wear resistance was developed ,which combined with SLTIT type torsional impact tool suitable for PDC’ s rock shear breaking mechanism ,forming a composite drilling technique .The technique showed effective performance in drilling igneous rocks in Well Hashan 3 .In field application ,φ311.1 mm PK6245MJD PDC bit and SLTIT type torsional impact tool reached a continuous working time of 649 h with 457.50 m of drilling footage in one trip .The ROP was 1.0 m/h ,and its roundtrip ROP was 0.7 m/h .Com-pared with the drilling situation of adjacent upper igneous rocks ,at least 11 trip times and bit cost were saved . At the same time well deviation dropped from 4.2° at 2 882 m down to 1.2° at 3 310 m .So the composite drilling technique with φ311.1 mm PK6245MJD PDC bit and SLTIT type torsional impact tool is an effective way to realize optimal and fast drilling in igneous rock formations of Junggar Basin .%为解决准噶尔盆地火成岩地层岩石坚硬、可钻性差、井斜问题突出等技术难点,进行了火成岩地层“PDC钻头+扭转冲击工具”复合钻井技术研究。针对火成岩地层岩性特点和钻井技术难点,通过研制具有较强耐磨性的φ311.1 mm PK6245M JD型PDC钻头,与适合PDC钻头机械剪切破岩机理的SL T IT型扭转冲击工具配合形成了“高效PDC钻头+SLTIT型扭转冲击工具”复合钻井技术,并在哈山3井火成岩地层取得了较好的应用效果。现场应用发现,“φ311.1 mm PK6245MJD型PDC钻头+SLTIT型扭转冲

  13. Exciton dynamics in near-surface InGaN quantum wells coupled to colloidal nanocrystals

    DEFF Research Database (Denmark)

    Kopylov, Oleksii; Shirazi, Roza; Yvind, Kresten;

    2013-01-01

    We study non-radiative energy transfer between InGaN quantum wells and colloidal InP nanocrystals separated by sub-10nm distance. A significant non-radiative energy transfer between the two layers is accompanied by reduced surface recombination in InGaN....

  14. Drag reduction in reservoir rock surface: Hydrophobic modification by SiO2 nanofluids

    Science.gov (United States)

    Yan, Yong-Li; Cui, Ming-Yue; Jiang, Wei-Dong; He, An-Le; Liang, Chong

    2017-02-01

    Based on the adsorption behavior of modified silica nanoparticles in the sandstone core surface, the hydrophobic surface was constructed, which consists of micro-nanoscale hierarchical structure. This modified core surface presents a property of drag reduction and meets the challenge of high injection pressure and low injection rate in low or ultra-low permeability reservoir. The modification effects on the surface of silica nanoparticles and reservoir cores, mainly concerning hydrophobicity and fine structure, were determined by measurements of contact angle and scanning electron microscopy. Experimental results indicate that after successful modification, the contact angle of silica nanoparticles varies from 19.5° to 141.7°, exhibiting remarkable hydrophobic properties. These modified hydrophobic silica nanoparticles display a good adsorption behavior at the core surface to form micro-nanobinary structure. As for the wettability of these modified core surfaces, a reversal has happened from hydrophilic into hydrophobic and its contact angle increases from 59.1° to 105.9°. The core displacement experiments show that the relative permeability for water has significantly increased by an average of 40.3% via core surface modification, with the effects of reducing injection pressure and improving injection performance of water flooding. Meanwhile, the mechanisms of drag reduction and improving water injection operation induced from the modified core surface were uncovered. The present study will establish a fundamental understanding on the drag reduction at the core surface modified by nanofluids and its applications in more industries.

  15. 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

  16. Application of Response Surface Methodology on Leaching of Iron from Partially Laterised Khondalite Rocks: A Bauxite Mining Waste

    Science.gov (United States)

    Swain, Ranjita; Bhima Rao, R.

    2017-08-01

    In the present investigation, response surface methodology (RSM) is used for a quadratic model that continuously controls the process parameters. This model is used to optimize the removal of iron oxide from Partially Laterised Khondalite (PLK) rocks which is influenced by several independent variables namely acid concentration, time and temperature. Second order response functions are produced for leaching of iron oxide from PLK rocks-a bauxite mining waste. In RSM, Box-Behnken design is used for the process optimization to achieve maximum removal of iron oxide. The influence of the process variables of leaching of iron oxide is presented in the form of 3-D response graphs. The results of this investigation reveals that 3 M hydrochloric acid concentration, 240 min time and 373 K temperature are found to be the best conditions for removal of 99% Fe2O3. The product obtain at this condition contain 80% brightness which is suitable for ceramic and filler industry applications. The novelity of the work is that the waste can be a value added product after suitable physical beneficiation and chemical treatment.

  17. Source rock

    OpenAIRE

    Abubakr F. Makky; Mohamed I. El Sayed; Ahmed S. Abu El-Ata; Ibrahim M. Abd El-Gaied; Mohamed I. Abdel-Fattah; Zakaria M. Abd-Allah

    2014-01-01

    West Beni Suef Concession is located at the western part of Beni Suef Basin which is a relatively under-explored basin and lies about 150 km south of Cairo. The major goal of this study is to evaluate the source rock by using different techniques as Rock-Eval pyrolysis, Vitrinite reflectance (%Ro), and well log data of some Cretaceous sequences including Abu Roash (E, F and G members), Kharita and Betty formations. The BasinMod 1D program is used in this study to construct the burial history ...

  18. Surface modification with well-defined biocompatible triblock copolymers Improvement of biointerfacial phenomena on a poly(dimethylsiloxane) surface.

    Science.gov (United States)

    Iwasaki, Yasuhiko; Takamiya, Mika; Iwata, Ryoko; Yusa, Shin-Ichi; Akiyoshi, Kazunari

    2007-06-15

    To improve interfacial phenomena of poly(dimethylsiloxane) (PDMS) as biomaterials, well-defined triblock copolymers were prepared as coating materials by reversible addition-fragmentation chain transfer (RAFT) controlled polymerization. Hydroxy-terminated poly(vinylmethylsiloxane-co-dimethylsiloxane) (HO-PV(l)D(m)MS-OH) was synthesized by ring-opening polymerization. The copolymerization ratio of vinylmethylsiloxane to dimethylsiloxane was 1/9. The molecular weight of HO-PV(l)D(m)MS-OH ranged from (1.43 to 4.44)x10(4), and their molecular weight distribution (M(w)/M(n)) as determined by size-exclusion chromatography equipped with multiangle laser light scattering (SEC-MALS) was 1.16. 4-Cyanopentanoic acid dithiobenzoate was reacted with HO-PV(l)D(m)MS-OH to obtain macromolecular chain transfer agents (macro-CTA). 2-Methacryloyloxyethyl phosphorylcholine (MPC) was polymerized with macro-CTAs. The gel-permeation chromatography (GPC) chart of synthesized polymers was a single peak and M(w)/M(n) was relatively narrow (1.3-1.6). Then the poly(MPC) (PMPC)-PV(l)D(m)MS-PMPC triblock copolymers were synthesized. The molecular weight of PMPC in a triblock copolymer was easily controllable by changing the polymerization time or the composition of the macro-CTA to a monomer in the feed. The synthesized block copolymers were slightly soluble in water and extremely soluble in ethanol and 2-propanol. Surface modification was performed via hydrosilylation. The block copolymer was coated on the PDMS film whose surface was pretreated with poly(hydromethylsiloxane). The surface wettability and lubrication of the PDMS film were effectively improved by immobilization with the block copolymers. In addition, the number of adherent platelets from human platelet-rich plasma (PRP) was dramatically reduced by surface modification. Particularly, the triblock copolymer having a high composition ratio of MPC units to silicone units was effective in improving the surface properties of PDMS. By

  19. Fractal Dimension of Fracture Surface in Rock Material after High Temperature

    Directory of Open Access Journals (Sweden)

    Z. Z. Zhang

    2015-01-01

    Full Text Available Experiments on granite specimens after different high temperature under uniaxial compression were conducted and the fracture surfaces were observed by scanning electron microscope (SEM. The fractal dimensions of the fracture surfaces with increasing temperature were calculated, respectively. The fractal dimension of fracture surface is between 1.44 and 1.63. Its value approximately goes up exponentially with the increase of temperature. There is a quadratic polynomial relationship between the rockburst tendency and fractal dimension of fracture surface; namely, a fractal dimension threshold can be obtained. Below the threshold value, a positive correlativity shows between rockburst tendency and fractal dimension; when the fractal dimension is greater than the threshold value, it shows an inverse correlativity.

  20. Pore Scale Heterogeneity in the Mineral Distribution and Surface Area of Porous Rocks

    Science.gov (United States)

    Lai, Peter; Krevor, Sam

    2015-04-01

    An important control on rate of interfacial processes between minerals and aqueous solutions such as nucleation of solids, and mineral dissolution and growth is reactive surface area. In geochemical modelling, the continuum hypothesis is based on the assumption that the system can be represented by a sufficiently large number of representative elemental volumes. There has been recent interest in studying the impact of this assumption on reaction-transport coupled systems. In this study, the impact of pore-scale heterogeneity on the distribution of reactive surface area is discussed. 3D images obtained using x-ray micro-tomography were used to characterise the distribution of reactive surface area. The results were compared to independent observations. Mineral identification using x- ray diffraction and fluorescence suggested general agreement with CT analysis. Nitrogen BET surface areas were one to two orders of magnitude higher than measurements from x-ray imagery. Co- registered images of Berea sandstone from x-ray and energy dispersive spectroscopy imagery suggested that quartz, K-feldspar and most clays could be identified. However, minor minerals such as albite and illite did not exhibit enough contrast. In Berea sandstone, mineral surface area fraction was poorly correlated to the mineral volumetric fraction. Clay and feldspar minerals exhibited higher surface area fractions than bulk mineralogy suggested. In contrast, in the Edwards carbonate samples, modal mineral composition correlated with mineral-specific surface area. Berea sandstone revealed a characteristic pore size at which a surface area distribution may be used to quantify heterogeneity. Conversely, the carbonate samples suggested a continuous range of pore sizes across length scales. A comparison with pore network model simulations from the literature was made. First order estimates of mineral specific correlations between geometric area measured in the x-ray images were used to convert the CT

  1. Multiparameter Correction Intensity of Terrestrial Laser Scanning Data as AN Input for Rock Surface Modelling

    Science.gov (United States)

    Paleček, V.; Kubíček, P.

    2016-06-01

    A large increase in the creation of 3D models of objects all around us can be observed in the last few years; thanks to the help of the rapid development of new advanced technologies for spatial data collection and robust software tools. A new commercially available airborne laser scanning data in Czech Republic, provided in the form of the Digital terrain model of the fifth generation as irregularly spaced points, enable locating the majority of rock formations. However, the positional and height accuracy of this type of landforms can reach huge errors in some cases. Therefore, it is necessary to start mapping using terrestrial laser scanning with the possibility of adding a point cloud data derived from ground or aerial photogrammetry. Intensity correction and noise removal is usually based on the distance between measured objects and the laser scanner, the incidence angle of the beam or on the radiometric and topographic characteristics of measured objects. This contribution represents the major undesirable effects that affect the quality of acquisition and processing of laser scanning data. Likewise there is introduced solutions to some of these problems.

  2. ULTimateCO2 project: Field experiment in an underground rock laboratory to study the well integrity in the context of CO2 geological storage

    NARCIS (Netherlands)

    Manceau, J.C.; Audigane, P.; Claret, F.; Parmentier, M.; Tambach, T.J.; Wasch, L.; Gherardi, F.; Dimier, A.; Ukelis, O.; Jeandel, E.; Cladt, F.; Zorn, R.; Yalamas, T.; Nussbaum, C.; Laurent, A.; Fierz, T.; Pieedevache, M.

    2013-01-01

    Wells drilled through low-permeable caprock are potential connections between the CO2 storage reservoir and overlying sensitive targets like aquifers and targets located at the surface. The wellbore integrity can be compromised due to in situ operations, including drilling, completion, operations

  3. Sliding rocks on Racetrack Playa, Death Valley National Park: first observation of rocks in motion.

    Science.gov (United States)

    Norris, Richard D; Norris, James M; Lorenz, Ralph D; Ray, Jib; Jackson, Brian

    2014-01-01

    The engraved trails of rocks on the nearly flat, dry mud surface of Racetrack Playa, Death Valley National Park, have excited speculation about the movement mechanism since the 1940s. Rock movement has been variously attributed to high winds, liquid water, ice, or ice flotation, but has not been previously observed in action. We recorded the first direct scientific observation of rock movements using GPS-instrumented rocks and photography, in conjunction with a weather station and time-lapse cameras. The largest observed rock movement involved > 60 rocks on December 20, 2013 and some instrumented rocks moved up to 224 m between December 2013 and January 2014 in multiple move events. In contrast with previous hypotheses of powerful winds or thick ice floating rocks off the playa surface, the process of rock movement that we have observed occurs when the thin, 3 to 6 mm, "windowpane" ice sheet covering the playa pool begins to melt in late morning sun and breaks up under light winds of -4-5 m/s. Floating ice panels 10 s of meters in size push multiple rocks at low speeds of 2-5 m/min. along trajectories determined by the direction and velocity of the wind as well as that of the water flowing under the ice.

  4. Sliding rocks on Racetrack Playa, Death Valley National Park: first observation of rocks in motion.

    Directory of Open Access Journals (Sweden)

    Richard D Norris

    Full Text Available The engraved trails of rocks on the nearly flat, dry mud surface of Racetrack Playa, Death Valley National Park, have excited speculation about the movement mechanism since the 1940s. Rock movement has been variously attributed to high winds, liquid water, ice, or ice flotation, but has not been previously observed in action. We recorded the first direct scientific observation of rock movements using GPS-instrumented rocks and photography, in conjunction with a weather station and time-lapse cameras. The largest observed rock movement involved > 60 rocks on December 20, 2013 and some instrumented rocks moved up to 224 m between December 2013 and January 2014 in multiple move events. In contrast with previous hypotheses of powerful winds or thick ice floating rocks off the playa surface, the process of rock movement that we have observed occurs when the thin, 3 to 6 mm, "windowpane" ice sheet covering the playa pool begins to melt in late morning sun and breaks up under light winds of -4-5 m/s. Floating ice panels 10 s of meters in size push multiple rocks at low speeds of 2-5 m/min. along trajectories determined by the direction and velocity of the wind as well as that of the water flowing under the ice.

  5. Surface motion of active rock glaciers in the Sierra Nevada, California, USA: inventory and a case study using InSAR

    Directory of Open Access Journals (Sweden)

    Lin Liu

    2013-01-01

    Full Text Available Despite the abundance of rock glaciers in the Sierra Nevada of California, USA, few efforts have been made to measure their surface flow. Here we use the interferometric synthetic aperture radar (InSAR technique to compile a~benchmark inventory describing the kinematic state of 59 active rock glaciers in this region. Statistically, these rock glaciers moved at speeds range from 15 cm yr−1 to 88 cm yr−1 with a mean value of 55 cm yr−1 in the late summer of 2007. We also find a spatial gradient: rock glaciers in the southern Sierra Nevada moved faster than the ones in the central Sierra Nevada. In addition to the inventory mapping, we also conduct a case study to measure the surface flow of the Mount Gibbs rock glacier in fine spatial and temporal detail. The InSAR measurements over this target reveal (1 that the spatial pattern of surface flow is influenced by surface geomorphological features and (2 a significant seasonal variation of flow speed whose peak value was 48 cm yr−1 in the fall, more than twice the minimum value observed in the spring. The seasonal variation lagged air temperatures by three months and likely results from temporal changes in mechanical strength of mixing debris and ice, internal melting of ice, and surface snow cover. Our finding on the seasonal variation of surface speed reinforces the importance of a long time series with high temporal sampling rates to detect possible long-term changes of rock glaciers in a warming climate.

  6. Surface motion of active rock glaciers in the Sierra Nevada, California, USA: inventory and a case study using InSAR

    Science.gov (United States)

    Liu, Lin; Millar, C. I.; Westfall, R. D.; Zebker, H. A.

    2013-01-01

    Despite the abundance of rock glaciers in the Sierra Nevada of California, USA, few efforts have been made to measure their surface flow. Here we use the interferometric synthetic aperture radar (InSAR) technique to compile a~benchmark inventory describing the kinematic state of 59 active rock glaciers in this region. Statistically, these rock glaciers moved at speeds range from 15 cm yr-1 to 88 cm yr-1 with a mean value of 55 cm yr-1 in the late summer of 2007. We also find a spatial gradient: rock glaciers in the southern Sierra Nevada moved faster than the ones in the central Sierra Nevada. In addition to the inventory mapping, we also conduct a case study to measure the surface flow of the Mount Gibbs rock glacier in fine spatial and temporal detail. The InSAR measurements over this target reveal (1) that the spatial pattern of surface flow is influenced by surface geomorphological features and (2) a significant seasonal variation of flow speed whose peak value was 48 cm yr-1 in the fall, more than twice the minimum value observed in the spring. The seasonal variation lagged air temperatures by three months and likely results from temporal changes in mechanical strength of mixing debris and ice, internal melting of ice, and surface snow cover. Our finding on the seasonal variation of surface speed reinforces the importance of a long time series with high temporal sampling rates to detect possible long-term changes of rock glaciers in a warming climate.

  7. Well-posedness for the Classical Stefan Problem and the Zero Surface Tension Limit

    Science.gov (United States)

    Hadžić, Mahir; Shkoller, Steve

    2016-11-01

    We develop a framework for a unified treatment of well-posedness for the Stefan problem with or without surface tension. In the absence of surface tension, we establish well-posedness in Sobolev spaces for the classical Stefan problem. We introduce a new velocity variable which extends the velocity of the moving free-boundary into the interior domain. The equation satisfied by this velocity is used for the analysis in place of the heat equation satisfied by the temperature. Solutions to the classical Stefan problem are then constructed as the limit of solutions to a carefully chosen sequence of approximations to the velocity equation, in which the moving free-boundary is regularized and the boundary condition is modified in a such a way as to preserve the basic nonlinear structure of the original problem. With our methodology, we simultaneously find the required stability condition for well-posedness and obtain new estimates for the regularity of the moving free-boundary. Finally, we prove that solutions of the Stefan problem with positive surface tension {σ} converge to solutions of the classical Stefan problem as {σ to 0}.

  8. 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.

  9. Near-surface electromagnetic, rock magnetic, and geochemical fingerprinting of submarine freshwater seepage at Eckernförde Bay (SW Baltic Sea)

    Science.gov (United States)

    Müller, Hendrik; von Dobeneck, Tilo; Nehmiz, Wiebke; Hamer, Kay

    2011-04-01

    Submarine groundwater discharge in coastal settings can massively modify the hydraulic and geochemical conditions of the seafloor. Resulting local anomalies in the morphology and physical properties of surface sediments are usually explored with seismo-acoustic imaging techniques. Controlled source electromagnetic imaging offers an innovative dual approach to seep characterization by its ability to detect pore-water electrical conductivity, hence salinity, as well as sediment magnetic susceptibility, hence preservation or diagenetic alteration of iron oxides. The newly developed electromagnetic (EM) profiler Neridis II successfully realized this concept for a first time with a high-resolution survey of freshwater seeps in Eckernförde Bay (SW Baltic Sea). We demonstrate that EM profiling, complemented and validated by acoustic as well as sample-based rock magnetic and geochemical methods, can create a crisp and revealing fingerprint image of freshwater seepage and related reductive alteration of near-surface sediments. Our findings imply that (1) freshwater penetrates the pore space of Holocene mud sediments by both diffuse and focused advection, (2) pockmarks are marked by focused freshwater seepage, underlying sand highs, reduced mud thickness, higher porosity, fining of grain size, and anoxic conditions, (3) depletion of Fe oxides, especially magnetite, is more pervasive within pockmarks due to higher concentrations of organic and sulfidic reaction partners, and (4) freshwater advection reduces sediment magnetic susceptibility by a combination of pore-water injection (dilution) and magnetite reduction (depletion). The conductivity vs. susceptibility biplot resolves subtle lateral litho- and hydrofacies variations.

  10. Location-Related Differences in Weathering Behaviors and Populations of Culturable Rock-Weathering Bacteria Along a Hillside of a Rock Mountain.

    Science.gov (United States)

    Wang, Qi; Wang, Rongrong; He, Linyan; Sheng, Xiafang

    2016-12-21

    Bacteria play important roles in rock weathering, elemental cycling, and soil formation. However, little is known about the weathering potential and population of bacteria inhabiting surfaces of rocks. In this study, we isolated bacteria from the top, middle, and bottom rock samples along a hillside of a rock (trachyte) mountain as well as adjacent soils and characterized rock-weathering behaviors and populations of the bacteria. Per gram of rock or surface soil, 10(6)-10(7) colony forming units were obtained and total 192 bacteria were isolated. Laboratory rock dissolution experiments indicated that the proportions of the highly effective Fe (ranging from 67 to 92 %), Al (ranging from 40 to 48 %), and Cu (ranging from 54 to 81 %) solubilizers were significantly higher in the top rock and soil samples, while the proportion of the highly effective Si (56 %) solubilizers was significantly higher in the middle rock samples. Furthermore, 78, 96, and 6 % of bacteria from the top rocks, soils, and middle rocks, respectively, significantly acidified the culture medium (pH rock dissolution process. Most rock-weathering bacteria (79 %) from the rocks were different to those from the soils and most of them (species level) have not been previously reported. Furthermore, location-specific rock-weathering bacterial populations were found and Bacillus species were the most (66 %) frequently isolated rock-weathering bacteria in the rocks based on cultivation methods. Notably, the top rocks and soils had the highest and lowest diversity of rock-weathering bacterial populations, respectively. The results suggested location-related differences in element (Si, Al, Fe, and Cu) releasing effectiveness and communities of rock-weathering bacteria along the hillside of the rock mountain.

  11. Peculiar Betulia Re-visited: A Near-Earth Asteroid with a Bare-Rock Surface?

    NARCIS (Netherlands)

    Harris, A. W.; Mueller, M.; Delbo, M.; Bus, S. J.

    2005-01-01

    The small C-type asteroid (1580) Betulia is an unusual near-Earth object (NEO) with a lightcurve that changes dramatically with changing solar phase angle, presumably due to a highly irregular shape and/or unusual topographic features. Earlier thermal-infrared observations indicated a surface of hig

  12. Characterization of a complex near-surface structure using well logging and passive seismic measurements

    Science.gov (United States)

    Benjumea, Beatriz; Macau, Albert; Gabàs, Anna; Figueras, Sara

    2016-04-01

    We combine geophysical well logging and passive seismic measurements to characterize the near-surface geology of an area located in Hontomin, Burgos (Spain). This area has some near-surface challenges for a geophysical study. The irregular topography is characterized by limestone outcrops and unconsolidated sediments areas. Additionally, the near-surface geology includes an upper layer of pure limestones overlying marly limestones and marls (Upper Cretaceous). These materials lie on top of Low Cretaceous siliciclastic sediments (sandstones, clays, gravels). In any case, a layer with reduced velocity is expected. The geophysical data sets used in this study include sonic and gamma-ray logs at two boreholes and passive seismic measurements: three arrays and 224 seismic stations for applying the horizontal-to-vertical amplitude spectra ratio method (H/V). Well-logging data define two significant changes in the P-wave-velocity log within the Upper Cretaceous layer and one more at the Upper to Lower Cretaceous contact. This technique has also been used for refining the geological interpretation. The passive seismic measurements provide a map of sediment thickness with a maximum of around 40 m and shear-wave velocity profiles from the array technique. A comparison between seismic velocity coming from well logging and array measurements defines the resolution limits of the passive seismic techniques and helps it to be interpreted. This study shows how these low-cost techniques can provide useful information about near-surface complexity that could be used for designing a geophysical field survey or for seismic processing steps such as statics or imaging.

  13. How well-connected is the surface of the global ocean?

    Science.gov (United States)

    Froyland, Gary; Stuart, Robyn M; van Sebille, Erik

    2014-09-01

    The Ekman dynamics of the ocean surface circulation is known to contain attracting regions such as the great oceanic gyres and the associated garbage patches. Less well-known are the extents of the basins of attractions of these regions and how strongly attracting they are. Understanding the shape and extent of the basins of attraction sheds light on the question of the strength of connectivity of different regions of the ocean, which helps in understanding the flow of buoyant material like plastic litter. Using short flow time trajectory data from a global ocean model, we create a Markov chain model of the surface ocean dynamics. The surface ocean is not a conservative dynamical system as water in the ocean follows three-dimensional pathways, with upwelling and downwelling in certain regions. Using our Markov chain model, we easily compute net surface upwelling and downwelling, and verify that it matches observed patterns of upwelling and downwelling in the real ocean. We analyze the Markov chain to determine multiple attracting regions. Finally, using an eigenvector approach, we (i) identify the five major ocean garbage patches, (ii) partition the ocean into basins of attraction for each of the garbage patches, and (iii) partition the ocean into regions that demonstrate transient dynamics modulo the attracting garbage patches.

  14. Electrical injection to contactless near-surface InGaN quantum well

    Energy Technology Data Exchange (ETDEWEB)

    Riuttanen, L., E-mail: lauri.riuttanen@aalto.fi; Svensk, O.; Suihkonen, S. [Department of Micro- and Nanosciences, Aalto University, P.O. Box 13500, FI-00076 Aalto (Finland); Kivisaari, P.; Oksanen, J. [Department of Biomedical Engineering and Computational Science, Aalto University, P.O. Box 12200, FI-00076 Aalto (Finland)

    2015-08-03

    Charge injection to the prevailing and emerging light-emitting devices is almost exclusively based on the double heterojunction (DHJ) structures that have remained essentially unchanged for decades. In this letter, we report the excitation of a near surface indium gallium nitride (InGaN) quantum well (QW) by bipolar carrier diffusion from a nearby electrically excited pn-homojunction. The demonstrated near surface QW emitter is covered only by a 10 nm GaN capping leaving the light-emitting mesa perfectly free of metals, other contact, or current spreading structures. The presented proof-of-principle structure, operating approximately with a quantum efficiency of one fifth of a conventional single QW reference structure, provides conclusive evidence of the feasibility of using diffusion injection to excite near surface light-emitting structures needed, e.g., for developing light emitters or photo-voltaic devices based on nanoplasmonics or free-standing nanowires. In contrast to the existing DHJ solutions or optical pumping, our approach allows exciting nanostructures without the need of forming a DHJ, absorbing layers or even electrical contacts on the device surface.

  15. Applicability of surface directional wells for upper Silesia Basin coal seams’ drainage ahead of mining

    Institute of Scientific and Technical Information of China (English)

    Jura Bartłomiej; Skiba Jacek; Wierzbinski Krystian

    2014-01-01

    Methods of exploitation drainage, which is presently applied in polish hard coal mines in Upper Silesian Coal Basin (Poland), are not effective enough, high risk of methane hazard can be observed, and produc-tion capacity of the mining plant is not fully used. Methane hazard, which may occur during planned coal exploitation, is presented in this paper. Following parameters are taken into consideration in the fore-casts:coal extraction parameters, geological and mining conditions, deposit’s methane saturation degree and impact of coal exploitation on the degasification coefficient of the seams, which are under the influ-ence of relaxation zone. This paper presents the results of the analysis aiming to verify applicability of drainage ahead of mining of the coal seams by using surface directional wells. Based on the collected data (coal seams’ structural maps, profiles of the exploratory wells, geological cross-sections), the lab tests of drilling cores and direct wells’ tests, static model of the deposit was constructed and suitable grid of directional wells from the surface was designed. Comparison of forecasted methane emission volume between the two methods is investigated. The results indicated the necessity of performing appropriate deposit’s stimulations in order to increase effectiveness of drainage ahead of mining.

  16. Mechanics of weathered clay-marl rock masses along the rupture surface in homogeneous dry slopes

    Directory of Open Access Journals (Sweden)

    Kostić Srđan

    2016-01-01

    Full Text Available Authors analyze stress-strain distribution within slope using the shear stress reduction technique based on finite element method, which was previously confirmed to provide approximately the same results as the Janbu's corrected limit equilibrium method. Results obtained indicate that the largest vertical displacements occur at the slope base and crest, while central part of the slope is exposed to the largest horizontal displacements. Normal and shear stress show maximum values in the middle part of the slope. It was also determined that separate stress-strain relations could be derived for the exact upper and lower part of the rupture surface. [Projekat Ministarstva nauke Republike Srbije, br. 37005

  17. Geophysical prospecting method in intrusive rocks area fight a drought to find water wells set%物探方法在侵入岩地区抗旱找水定井中的应用

    Institute of Scientific and Technical Information of China (English)

    宋希利; 宋鹏; 田明阳; 彭玉明

    2012-01-01

    Intrusive rocks in the area of groundwater is difficult to find, but more abundant in the dry season the groundwater more difficult to find, to quickly resolve severe drought disaster in Shandong Yimcngshan people much-needed human and livestock water consumption through advanced and effective geophysical methods and reasonable working arrangement greatly increased drought in the intrusive rocks in the area to find water wells set the speed and rate guarantees as well, by the construction of drilling results verify the geophysical inference realistic, given the success rate of 96% well, single-well water yield are far beyond the estimated amount of water, to find a more extensive local groundwater resources, water resources needed to solve the problem of the masses, the people and the old liberated areas have been highly appreciated by the local government. Proved Yimengshan intrusive rocks in the area of geophysical methods based on different characteristics and be well area is difficult, easy, and CSAMT method were selected degree of resistivity sounding method to find underground water source not only improves the speed and success rate of well set, but also made good hydrogeological effects, it is in similar application areas. Practical work in the specific practice, one can not determine the geological survey of the ground target range and set well drilling difficult areas, the use of controlled source audio magnetotelluric: method is fast and efficient features, to sweep the work surface, suggesting that rock construction of fracture zone, delineated area that is rock crushing low resistance, water lots, and to determine the depth of drilling wells; the second is on the ground within the geological survey to determine, using the resistivity sounding method, the use of a single curve reflects the broken rocks, water section to determine the visual characteristics of the aquifer and depth.%侵入岩地区寻找地下水难度大,而在干旱季节找出较为

  18. A Model for Generation of Martian Surface Dust, Soil and Rock Coatings: Physical vs. Chemical Interactions, and Palagonitic Plus Hydrothermal Alteration

    Science.gov (United States)

    Bishop, J. L.; Murchie, S.; Pieters, C.; Zent, A.

    1999-01-01

    This model is one of many possible scenarios to explain the generation of the current surface material on Mars using chemical, magnetic and spectroscopic data from Mars and geologic analogs from terrestrial sites. One basic premise is that there are physical and chemical interactions of the atmospheric dust particles and that these two processes create distinctly different results. Physical processes distribute dust particles on rocks, forming physical rock coatings, and on the surface between rocks forming soil units; these are reversible processes. Chemical reactions of the dust/soil particles create alteration rinds on rock surfaces or duricrust surface units, both of which are relatively permanent materials. According to this model the mineral components of the dust/soil particles are derived from a combination of "typical" palagonitic weathering of volcanic ash and hydrothermally altered components, primarily from steam vents or fumeroles. Both of these altered materials are composed of tiny particles, about 1 micron or smaller, that are aggregates of silicates and iron oxide/oxyhydroxide/sulfate phases. Additional information is contained in the original extended abstract.

  19. Method based on artificial excitation of characteristic radiation by an electron beam for remote X-ray spectral elemental analysis of surface rocks on atmosphereless celestial bodies

    Science.gov (United States)

    Kolesnikov, E. K.

    2016-11-01

    This article, like our previous one [1], is devoted to advanced space technology concepts. It evaluates the potential for developing active systems to conduct a remote elemental analysis of surface rocks on an atmosphereless celestial body. The analysis is based on the spectrometry of characteristic X-rays (CXR) artificially excited in the surface soil layer. It has been proposed to use an electron beam injected from aboard a spacecraft orbiting the celestial body (or moving in a flyby trajectory) to excite the CXR elements contained in surface rocks. The focus is on specifying technical requirements to the parameters of payloads for a global mapping of the composition of lunar rocks from aboard of a low-orbiting lunar satellite. This article uses the results obtained in [2], our first study that shows the potential to develop an active system for a remote elemental analysis of lunar surface rocks using the above method. Although there has been interest in our research on the part of leading national academic institutions and space technology developers in the Soviet Union, the studies were discontinued because of the termination of the Soviet lunar program and the completion of the American Apollo program.

  20. Exciton spectrum of surface-corrugated quantum wells: the adiabatic self-consistent approach

    Energy Technology Data Exchange (ETDEWEB)

    Atenco A, N.; Perez R, F. [lnstituto de Fisica, Universidad Autonoma de Puebla, A.P. J-48, 72570 Puebla (Mexico); Makarov, N.M. [lnstituto de Ciencias, Universidad Autonoma de Puebla, Priv. 17 Norte No 3417, Col. San Miguel Hueyotlipan, 72050 Puebla (Mexico)

    2005-07-01

    A theory for calculating the relaxation frequency {nu} and the shift {delta} {omega} of exciton resonances in quantum wells with finite potential barriers and adiabatic surface disorder is developed. The adiabaticity implies that the correlation length R{sub C} for the well width fluctuations is much larger than the exciton radius a{sub 0} (R{sub C} >> a{sub 0}). Our theory is based on the self-consistent Green's function method, and therefore takes into account the inherent action of the exciton scattering on itself. The self-consistent approach is shown to describe quantitatively the sharp exciton resonance. It also gives the qualitatively correct resonance picture for the transition to the classical limit, as well as within the domain of the classical limit itself. We present and analyze results for h h-exciton in a GaAs quantum well with Al{sub 0.3} Ga{sub 0.7}As barriers. It is established that the self-consistency and finite height of potential barriers significantly influence on the line-shape of exciton resonances, and make the values of {nu} and {delta} {omega} be quite realistic. In particular, the relaxation frequency {nu} for the ground-state resonance has a broad, almost symmetric maximum near the resonance frequency {omega}{sub 0}, while the surface-induced resonance shift {delta} {omega} vanishes near {omega}{sub 0}, and has different signs on the sides of the exciton resonance. (Author) 43 refs., 4 figs.

  1. Characterization of reservoir rocks and fluids by surface electromagnetic transient methods

    Energy Technology Data Exchange (ETDEWEB)

    Hoekstra, P.; Blohm, M.W. (Blackhawk Geosciences, Inc., Golden, CO (United States)); Stoyer, C.H. (Interpex Ltd. (United States)); James, B.A. (James Consulting Services (United States))

    1992-01-01

    The objectives of this research are to improve the interpretations of transient electromagnetic (TEM) measurements over two-dimensional subsurface structures. TEM is a surface electromagnetic method employed in fossil energy reservoir exploration and characterization. Electrical measurements find application in (i) assisting in fossil energy exploration mainly in areas where seismic methods yield inadequate data quality, such as volcanic covered terrain, permafrost areas, and the Rocky Mountain overthrust; (ii) mapping contacts between hydrocarbon and brines in shallow producing horizons, and (iii) in monitoring enhanced oil recovery processes which cause zones of lower resistivity. Accomplishments for this past year are presented for the following tasks: (1) site selection and acquisition of high density, 3-component TEM data set over test site; (2) finite element forward modeling; and (3) TEM 2-D subsurface imaging.

  2. Structure, thermodynamic and surface properties of liquid metals investigated by Square well potential

    Science.gov (United States)

    Lalneihpuii, R.; Mishra, Raj Kumar

    2016-10-01

    The auto correlation function, S(k) (where k = 4π/λsinθ) and its Fourier component g(r) are important quantities characterizing the structure of a liquid. Experimentally these quantities have been determined using neutron or X-ray scattering intensities. Wertheim's solution of the fundamental statistical mechanical equation given by Percus and Yevick for hard spheres mixture is invoked with square well attractive part as a perturbation tail to evaluate the direct correlation function C(k) in momentum space through which structure factor, S(k) of liquid metals were derived. Radial distribution function, g(r) is obtained by Fourier analysis of computed S(k) from which the coordination numbers of ten liquid metals were computed. Surface tension of atomic liquids in terms of diffusion coefficient has been determined under square well interaction. The computed values of structural dependent coordination number, diffusion coefficient and surface tension of these liquid metals are compared with the available experimental results and a good agreement is found between the computed and experimental results

  3. A possible climate signal in the surface morphology and internal structure of Galena Creek Rock Glacier, Wyoming

    Science.gov (United States)

    Petersen, Eric; Holt, John; Levy, Joseph; Stuurman, Cassie; Nerozzi, Stefano; Cardenas, Benjamin; Pharr, James; Aylward, Dan; Schmidt, Logan; Hoey, William; Prem, Parvathy; Rambo, Jackie; Lim, YeJin; Maharaj, Kian

    2016-04-01

    Galena Creek Rock Glacier (GCRG) has been shown in previous studies to be a debris-covered glacier (e.g. Ackert, Jr., 1998), and is thus a target of interest as a record of climate and an element of the mountain hydrological system. The goal of this study was to investigate possible relationships between surface morphology and internal structure and composition of GCRG. This was achieved using ground-penetrating radar (GPR), time-domain electromagnetic sounding (TEM), and photogrammetry to produce digital terrain models (DTMs). We acquired 6 longitudinal GPR surveys at 50 and 100 MHz, 2 common midpoint GPR surveys, and 28 TEM soundings on GCRG from the head to the toe, and ground-based photogrammetry data were collected to produce a DTM of its cirque at 10 cm resolution. TEM soundings locally constrained the bulk thickness of GCRG to 26-75 meters. Common midpoint and hyperbola analyses of GPR surveys produced dielectric constants in the near subsurface of 4 in the upper glacier to 5-9 in the middle and lower glacier. These are consistent with clean ice and a mélange of rock with air and/or ice, respectively. GPR revealed a pervasive shallow reflector at 1-2.5m depth that we interpret to be the interface between the surface debris layer and glacier ice. There is increased structure and clutter in the GPR data beneath this interface as one moves down glacier. Observations were additionally made of a 40m wide, 4-5m deep circular thermokarst pond located on upper GCRG in the cirque. The walls of the pond revealed a cross-section of the top several meters of GCRG's interior: a dry surface layer of rocky debris 1-1.5m thick overlying pure glacier ice. An englacial debris band was also observed, roughly 50 cm thick and presenting at an apparent up-glacier dip of ~30 degrees, intersecting the surface near a subtle ridge resolved in the photogrammetry DTM. A GPR transect conducted near the pond over 6 similar ridges imaged 6 corresponding up-glacier dipping reflectors that

  4. Do Bare Rocks Exist on the Moon?

    Science.gov (United States)

    Allen, Carlton; Bandfield, Joshua; Greenhagen, Benjamin; Hayne, Paul; Leader, Frank; Paige, David

    2017-01-01

    Astronaut surface observations and close-up images at the Apollo and Chang'e 1 landing sites confirm that at least some lunar rocks have no discernable dust cover. However, ALSEP (Apollo Lunar Surface Experiments Package) measurements as well as astronaut and LADEE (Lunar Atmosphere and Dust Environment Explorer) orbital observations and laboratory experiments possibly suggest that a fine fraction of dust is levitated and moves across and above the lunar surface. Over millions of years such dust might be expected to coat all exposed rock surfaces. This study uses thermal modeling, combined with Diviner (a Lunar Reconnaissance Orbiter experiment) orbital lunar eclipse temperature data, to further document the existence of bare rocks on the lunar surface.

  5. Hydrogenation of nitriles on a well-characterized nickel surface: From surface science studies to liquid phase catalytic activity measurements

    Energy Technology Data Exchange (ETDEWEB)

    Gardin, D.E.

    1993-12-01

    Nitrile hydrogenation is the most commonly used method for preparing diverse amines. This thesis is aimed at the mechanism and factors affecting the performance of Ni-based catalysts in nitrile hydrogenations. Surface science techniques are used to study bonding of nitriles and amines to a Ni(111) surface and to identify surface intermediates. Liquid-phase hydrogenations of cyclohexene and 1-hexene on a Pt foil were carried out successfully. Finally, knowledge about the surface structure, surface chemical bond, dynamics of surface atoms (diffusion, growth), and reactivity of metal surfaces from solid-gas interface studies, is discussed.

  6. Upscaling of the specific surface area for reactive transport modelling in fractured rock

    Science.gov (United States)

    Cvetkovic, Vladimir

    2014-05-01

    The impact of flow heterogeneity on chemical transport from single to multiple fractures, is investigated. The emphasis is on the dynamic nature of the specific surface area (SSA) due to heterogeneity of the flow, relative to a purely geometrical definition. It is shown how to account for SSA as a random variable in modelling multi-component reactions. The flow-dependent SSA is interpreted probabilistically, following inert tracer particles along individual fractures. Upscaling to a fracture network is proposed as a time-domain random walk based on the statistics of SSA for single fractures. Statistics of SSA are investigated for three correlation structures of transmissivity, one classical multi-gaussian, and two non-Gaussian. The coefficient of variation of single fracture SSA decreases monotonously with the distance over the fracture length; the CV of the upscaled SSA reduces further such that after ca 20 fractures it is under 0.1 for a disconnected field, and around 0.2 for connected and multi-gaussian fields. This implies that after 10-20 fractures, uncertainty in SSA is significantly reduced, justifying the use of an effective value. A conservative, lower bound for the dimensionless upscaled effective SSA was found to be 1, suitable for all heterogeneity structures, assuming the cubic hydraulic law applicable.

  7. Rock size distributions on lava flow surfaces: New results from a range of compositions

    Science.gov (United States)

    Burke, M. P.; Anderson, S. W.; Bulmer, M. H.

    2005-12-01

    We measured block sizes along 15-25m orthogonal transects on 12 lava flows of compositions ranging from basalt to rhyolite. At each site, we stretched a line across the flow surface then measured the length of each block cut by this line that were greater than 3-12cm (depending on composition). The measurements from each site were reduced to cumulative size frequency distribution plots, with block size (D) plotted against the fraction of the line f(D) composed of blocks greater than or equal to that size, and fitted with an exponential curve of the form f(D) = k exp(-qD) where k is the intercept and q is the decay parameter. Average block size and geometric mean were also determined for each site. Our data show no clear trends linking average or mean block size to composition, although there does seem to be relationship between block size and the decay parameter. Block size corresponds with the decay parameter at each site except for the basaltic andesite flow at Paint Pot Crater (CA). Many sites at this flow were covered with secondary spatter deposits. Largest blocks and smallest decay parameters were found for the andesite flows at Sabancaya (Peru), while the basalt flows at Cima (CA) exhibited the smallest blocks and largest decay parameters. The second largest block sizes occurred at the four Inyo domes composed of both crystal-rich and glassy rhyolite, and these domes also showed the second smallest decay parameters. All four of the Inyo domes were emplaced along the same feeder dike trend, and the average and mean sizes and decay parameters at these domes are nearly identical, suggesting that composition, extrusion rate, or eruption history controls the block size distributions. However, values for the two andesitic flows, Mt. Shasta (CA) and Sabancaya, were very different, suggesting that extrusion rate and/or eruption history exert a stronger control over the block size distributions than does composition. LIDAR data sets are capable of detecting sub

  8. The ROCK inhibitor Y-27632 improves recovery of human embryonic stem cells after fluorescence-activated cell sorting with multiple cell surface markers.

    Directory of Open Access Journals (Sweden)

    Nil Emre

    Full Text Available BACKGROUND: Due to the inherent sensitivity of human embryonic stem cells (hESCs to manipulations, the recovery and survival of hESCs after fluorescence-activated cell sorting (FACS can be low. Additionally, a well characterized and robust methodology for performing FACS on hESCs using multiple-cell surface markers has not been described. The p160-Rho-associated coiled kinase (ROCK inhibitor, Y-27632, previously has been identified as enhancing survival of hESCs upon single-cell dissociation, as well as enhancing recovery from cryopreservation. Here we examined the application of Y-27632 to hESCs after FACS to improve survival in both feeder-dependent and feeder-independent growth conditions. METHODOLOGY/PRINCIPAL FINDINGS: HESCs were sorted using markers for SSEA-3, TRA-1-81, and SSEA-1. Cells were plated after sorting for 24 hours in either the presence or the absence of Y-27632. In both feeder-dependent and feeder-independent conditions, cell survival was greater when Y-27632 was applied to the hESCs after sort. Specifically, treatment of cells with Y-27632 improved post-sort recovery up to four fold. To determine the long-term effects of sorting with and without the application of Y-27632, hESCs were further analyzed. Specifically, hESCs sorted with and without the addition of Y-27632 retained normal morphology, expressed hESC-specific markers as measured by immunocytochemistry and flow cytometry, and maintained a stable karyotype. In addition, the hESCs could differentiate into three germ layers in vitro and in vivo in both feeder-dependent and feeder-independent growth conditions. CONCLUSIONS/SIGNIFICANCE: The application of Y-27632 to hESCs after cell sorting improves cell recovery with no observed effect on pluripotency, and enables the consistent recovery of hESCs by FACS using multiple surface markers. This improved methodology for cell sorting of hESCs will aid many applications such as removal of hESCs from secondary cell types

  9. Effects of mineral surfaces on pyrene partitioning to well-characterized humic substances.

    Science.gov (United States)

    Hur, Jin; Schlautman, Mark A

    2004-01-01

    Mineral surfaces can alter the ability of humic substances (HS) to bind hydrophobic organic contaminants. In this study, complete adsorption (i.e., to avoid HS adsorptive fractionation effects) of a small subset of well-characterized terrestrial and aquatic HS on kaolinite and hematite significantly changed their subsequent organic carbon-normalized partition coefficients K(ads)(oc) for pyrene relative to their original respective dissolved organic carbon-normalized partition coefficients K(dis)(oc). Parallel experiments with ultrafiltration (UF) fractions obtained from purified Aldrich humic acid (PAHA) (Aldrich Chemical, Milwaukee, WI) gave similar results. The heterogeneity among the PAHA UF fractions was examined via their mineral surface adsorption characteristics and their subsequent ability to bind pyrene. As expected, variations in maximum adsorption densities (q(max)), Langmuir adsorption constants (K(q)), and pyrene K(ads)(oc) values were observed among the PAHA UF fractions. However, general trends of q(max), K(q), and pyrene log K(ads)(oc) values for the PAHA UF fractions versus the logarithm of their weight-average molecular weights (MW(w)) did not typically match the corresponding trends obtained with the four aquatic and terrestrial HS. In general, an ideal mixture competitive adsorption model gave reasonable predictions for PAHA sorption to kaolinite and hematite based on their corresponding UF isotherm parameters. Ideal mixture predictions of pyrene partitioning to adsorbed PAHA from the corresponding UF fraction results were better for kaolinite versus hematite, indicating that the underlying mineral surface can alter the effects of HS heterogeneity on hydrophobic organic contaminant sorption.

  10. Silicon quantum wires on Ag(1 1 0): Fermi surface and quantum well states

    Energy Technology Data Exchange (ETDEWEB)

    Valbuena, M.A. [Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Cientificas (CSIC), C/ Sor Juana Ines de la Cruz, 3, 28049 Madrid (Spain); Avila, J. [Synchrotron SOLEIL, Orme des Merisiers, Saint Aubin BP 48, 91192 Gif sur Yvette Cedex (France)], E-mail: jose.avila@synchrotron-soleil.fr; Davila, M.E. [Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Cientificas (CSIC), C/ Sor Juana Ines de la Cruz, 3, 28049 Madrid (Spain); Leandri, C.; Aufray, B.; Le Lay, G. [CRMCN-CNRS, Campus de Luminy, Case 913, 13288 Marseille Cedex 9 (France); Asensio, M.C. [Synchrotron SOLEIL, Orme des Merisiers, Saint Aubin BP 48, 91192 Gif sur Yvette Cedex (France)

    2007-10-31

    One-dimensional Si quantum wires have been grown on silver single crystals upon deposition of {approx}0.25 monolayer of Si on Ag(1 1 0) surfaces. Scanning tunneling microscopy (STM) clearly shows parallel 1D Si chains along the [-1 1 0] Ag crystallographic direction. Low Energy Electron Diffraction (LEED) confirms the massively parallel assembly of these selforganized Nanowires (NWs). We have characterized these nano-objects by measuring the dispersion of the NWs valence band at room temperature using Angle-Resolved PhotoEmission Spectroscopy (ARPES). Also, the Fermi Surface (FS) of the Ag(1 1 0) substrate has been mapped before and after the silicon deposition, trying to put in evidence the metallic or semiconductor character of the NWs silicon's states close to the Fermi level. Our results show the existence of well-defined quantum states associated to the silicon super-structure. Both LEED and ARUPS results confirm that the NWs have typical 1D features, however their metallic or semiconductor character could not be confirmed.

  11. Hydrothermal alteration at the Roosevelt Hot Springs Thermal Area, Utah: modal mineralogy, and geochemistry of sericite, chlorite, and feldspar from altered rocks, Thermal Power Company well Utah State 14-2

    Energy Technology Data Exchange (ETDEWEB)

    Ballantyne, J.M.

    1978-11-01

    Sericites, chlorites, feldspars, biotite and hornblende from hydrothermally altered rocks at several depths in Thermal Power Company well Utah State 14-2, Roosevelt Hot Springs Thermal Area, Utah, have been analyzed using the electron microprobe. Sericites and ferromagnesian minerals have been analyzed for 12 major elements, and feldspars for 3. The results have been used, along with whole rock chemical analyses, to computer calculate modal mineralogy for samples from the drillhole. Calculated modes for hydrothermal minerals are in reasonable agreement with observations from thin sections.

  12. Exploitation technology of pressure relief coalbed methane in vertical surface wells in the Huainan coal mining area

    Institute of Scientific and Technical Information of China (English)

    HAN Jia-zhang; SANG Shu-xun; CHENG Zhi-zhong; HUANG Hua-zhou

    2009-01-01

    Exploitation technology of pressure relief coalbed methane in vertical surface wells is a new method for exploration of gas and coalbed methane exploitation in mining areas with high concentrations of gas, where tectonic coal developed. Studies on vertical surface well technology in the Huainan Coal Mining area play a role in demonstration in the use of clean, new energy re-sources, preventing and reducing coal mine gas accidents and protecting the environment. Based on the practice of gas drainage engineering of pressure relief coalbed methane in vertical surface wells and combined with relative geological and exploration en-gineering theories, the design principles of design and structure of wells of pressure relief coaibed methane in vertical surface wells are studied. The effects of extraction and their causes are discussed and the impact of geological conditions on gas production of the vertical surface wells are analyzed. The results indicate that in mining areas with high concentrations of gas, where tectonic coal developed, a success rate of pressure relief coalbed methane in surface vertical well is high and single well production usually great. But deformation due to coal exploitation could damage boreholes and cause breaks in the connection between aquifers and bore-holes, which could induce a decrease, even a complete halt in gas production of a single well. The design of well site location and wellbore configuration are the key for technology. The development of the geological conditions for coalbed methane have a sig-nificant effect on gas production of coalbed methane wells.

  13. Rock2 controls TGFbeta signaling and inhibits mesoderm induction in zebrafish embryos.

    Science.gov (United States)

    Zhang, Yu; Li, Xiang; Qi, Jingjing; Wang, Jialu; Liu, Xingfeng; Zhang, Haiwen; Lin, Sheng-Cai; Meng, Anming

    2009-07-01

    The Rho-associated serine/threonine kinases Rock1 and Rock2 play important roles in cell contraction, adhesion, migration, proliferation and apoptosis. Here we report that Rock2 acts as a negative regulator of the TGFbeta signaling pathway. Mechanistically, Rock2 binds to and accelerates the lysosomal degradation of TGFbeta type I receptors internalized from the cell surface in mammalian cells. The inhibitory effect of Rock2 on TGFbeta signaling requires its kinase activity. In zebrafish embryos, injection of rock2a mRNA attenuates the expression of mesodermal markers during late blastulation and blocks the induction of mesoderm by ectopic Nodal signals. By contrast, overexpression of a dominant negative form of zebrafish rock2a, dnrock2a, has an opposite effect on mesoderm induction, suggesting that Rock2 proteins are endogenous inhibitors for mesoderm induction. Thus, our data have unraveled previously unidentified functions of Rock2, in controlling TGFbeta signaling as well as in regulating embryonic patterning.

  14. Shock Propagation In Crustal Rock

    Science.gov (United States)

    1991-04-29

    Muscovite dehydroxylation: High-temperature studies, Am. Mineral., 72, 537-550, 1986. Halbach, H., and N. D. Chatterjee, An empirical Redlich - Kwong ...earth and other planetary surfaces as well having application in the study of the Earth’s interior. Granitic rocks are the most common component of...their applicability to muscovite above 1000 K. Thermodynamic functions for H20 were taken from Halbach and Chatterjee [1982]. Gibbs’ free energy

  15. Comparative study of static and dynamic parameters of rock for the Xishan Rock Cliff Statue

    Institute of Scientific and Technical Information of China (English)

    Jin JIANG; Jin-zhong SUN

    2011-01-01

    Ultrasonic wave testing was applied to investigate the quality and weathering status of rock specimens obtained in two borings situated in the Xishan Buddha rock slope in Taiyuan,China.This paper pays special attention to the distribution of bulk density,dynamic parameters and static parameters of rock specimens as well as the relationship between static and dynamic parameters.The results illustrate that the distribution of both parameters is identical along the depth of two drilled holes in the rock slope.When the hole depth increases,the density of rock mass,saturated compression strength and static elastic modulus,dynamic elastic modulus and wave velocity also show increase tendency.The weathering degree in the rock mass ranging from the surface of cliffto the depth of 2.5 m is the highest while the rock mass is unsalted and more rigid when the depth is larger than 3.0 m.The relationship between dynamic elastic modulus,sonic wave velocity and horizontal depth indicates that dynamic elastic modulus is more sensitive than sonic wave velocity.Conversely,by comparing quantity relationship between static elastic modulus and sonic wave velocity,it is found that the composition of rock has a great influence on the relationship between static and dynamic parameters,that is,inequality of rock composition will lead to dispersion and abnormality of the distribution of static and dynamic parameters.

  16. Mass wasting process at the surface of the Sangun metamorphic rocks in Kaminishigawa area, Asahi-machi, Okayama Prefecture.

    OpenAIRE

    新宮原, 秀和; 平山, 恭之; 津島, 淳; 於保, 幸正

    1999-01-01

    The relation among microstructures, weathering and mass wasting of the Sangun metamorphic rocks in the Kaminishigawa area, Asahi-machi, Okayama Prefecture, was studied. Three stages of penetrative planar structures are recognized; S1 schistosity, S2 crenulation cleavage and S3 crenulation cleavage. The S2 cleavage is the most commonly observed structure. The deree of weathering is divided into two classes on the base of appearance; slightly weathered and highly weathered rock. The three types...

  17. Zinc isotope investigation of surface and pore waters in a mountain watershed impacted by acid rock drainage.

    Science.gov (United States)

    Aranda, Suzan; Borrok, David M; Wanty, Richard B; Balistrieri, Laurie S

    2012-03-15

    The pollution of natural waters with metals derived from the oxidation of sulfide minerals like pyrite is a global environmental problem. However, the metal loading pathways and transport mechanisms associated with acid rock drainage reactions are often difficult to characterize using bulk chemical data alone. In this study, we evaluated the use of zinc (Zn) isotopes to complement traditional geochemical tools in the investigation of contaminated waters at the former Waldorf mining site in the Rocky Mountains, Colorado, U.S.A. Geochemical signatures and statistical analysis helped in identifying two primary metal loading pathways at the Waldorf site. The first was characterized by a circumneutral pH, high alkalinity, and high Zn/Cd ratios. The second was characterized by acidic pHs and low Zn/Cd ratios. Zinc isotope signatures in surface water samples collected across the site were remarkably similar (the δ(66)Zn, relative to JMC 3-0749-L, for most samples ranged from 0.20 to 0.30‰±0.09‰ 2σ). This probably suggests that the ultimate source of Zn is consistent across the Waldorf site, regardless of the metal loading pathway. The δ(66)Zn of pore water samples collected within a nearby metal-impacted wetland area, however, were more variable, ranging from 0.20 to 0.80‰±0.09‰ 2σ. Here the Zn isotopes seemed to reflect differences in groundwater flow pathways. However, a host of secondary processes might also have impacted Zn isotopes, including adsorption of Zn onto soil components, complexation of Zn with dissolved organic matter, uptake of Zn into plants, and the precipitation of Zn during the formation of reduced sulfur species. Zinc isotope analysis proved useful in this study; however, the utility of this isotopic tool would improve considerably with the addition of a comprehensive experimental foundation for interpreting the complex isotopic relationships found in soil pore waters.

  18. Collecting Rocks

    Institute of Scientific and Technical Information of China (English)

    孙铮

    2007-01-01

    My hobby is collecting rocks.It is very special,isn’t it?I began to collect rocks about four years ago.I usually go hiking in the mountains,or near the river to look for rocks.When I find a rock,I pick it up and clean it with the brush and water.Then I put it into my bag.Most of the rocks I have collected are quartzite~*.They are really

  19. Uranium favorability of tertiary sedimentary rocks of the Pend Oreille River valley, Washington. [Measurement and sampling of surface sections, collection of samples from isolated outcrops, chemical and mineralogical analyses of samples, and examination of available water logs

    Energy Technology Data Exchange (ETDEWEB)

    Marjaniemi, D.K.; Robins, J.W.

    1975-08-01

    Tertiary sedimentary rocks in the Pend Oreille River valley were investigated in a regional study to determine the favorability for potential uranium resources of northeastern Washington. This project involved measurement and sampling of surface sections, collection of samples from isolated outcrops, chemical and mineralogical analyses of samples, and examination of available water well logs. The Box Canyon Dam area north of Ione is judged to have very high favorability. Thick-bedded conglomerates interbedded with sandstones and silty sandstones compose the Tiger Formation in this area, and high radioactivity levels are found near the base of the formation. Uranophane is found along fracture surfaces or in veins. Carbonaceous material is present throughout the Tiger Formation in the area. Part of the broad Pend Oreille valley surrounding Cusick, Washington, is an area of high favorability. Potential host rocks in the Tiger Formation, consisting of arkosic sandstones interbedded with radioactive shales, probably extend throughout the subsurface part of this area. Carbonaceous material is present and some samples contain high concentrations of uranium. In addition, several other possible chemical indicators were found. The Tiger-Lost Creek area is rated as having medium favorability. The Tiger Formation contains very hard, poorly sorted granite conglomerate with some beds of arkosic sandstone and silty sandstone. The granite conglomerate was apparently derived from source rocks having relatively high uranium content. The lower part of the formation is more favorable than the upper part because of the presence of carbonaceous material, anomalously high concentrations of uranium, and other possible chemical indicators. The area west of Ione is judged to have low favorability, because of the very low permeability of the rocks and the very low uranium content. (auth)

  20. Principles of rock mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Turchaninov, I.A.; Iofis, M.A.; Kasparyan, E.V.

    1979-01-01

    This book presents the principles of rock mechanics in a systematic way, reflecting both the historic development and the contemporary status of theoretical and experimental techniques used for the determination of the properties and stress state of rock masses, calculation of elements of systems for exploitation of useful mineral deposits and the design of mine openings. The subject of rock mechanics is discussed and methods and basic approaches are analyzed. The most widely used methods for determining the properties of rock in specimens and in situ are described. Problems of determining the stress strain state of the rock around mine openings by both experimental and analytic methods are discussed. The primary results of the study of the stress state of rock around main, development and production openings are presented. Problems of the movement of rock due to extraction of minerals are analyzed in detail, as are the conditions and causes of the development of rock bursts and sudden release of rock and gas in both surface and underground mines. Procedures for preventing or localizing rock bursts or sudden outbursts are described. (313 refs.)

  1. Zinc isotope investigation of surface and pore waters in a mountain watershed impacted by acid rock drainage

    Energy Technology Data Exchange (ETDEWEB)

    Aranda, Suzan [Department of Geological Sciences, University of Texas at El Paso, El Paso, TX 79968 (United States); Borrok, David M., E-mail: dborrok@utep.edu [Department of Geological Sciences, University of Texas at El Paso, El Paso, TX 79968 (United States); Wanty, Richard B. [US Geological Survey, MS 964d, Denver Federal Center, Denver, CO 80225 (United States); Balistrieri, Laurie S. [U.S. Geological Survey, University of Washington, School of Oceanography, Seattle, WA 98195 (United States)

    2012-03-15

    The pollution of natural waters with metals derived from the oxidation of sulfide minerals like pyrite is a global environmental problem. However, the metal loading pathways and transport mechanisms associated with acid rock drainage reactions are often difficult to characterize using bulk chemical data alone. In this study, we evaluated the use of zinc (Zn) isotopes to complement traditional geochemical tools in the investigation of contaminated waters at the former Waldorf mining site in the Rocky Mountains, Colorado, U.S.A. Geochemical signatures and statistical analysis helped in identifying two primary metal loading pathways at the Waldorf site. The first was characterized by a circumneutral pH, high alkalinity, and high Zn/Cd ratios. The second was characterized by acidic pHs and low Zn/Cd ratios. Zinc isotope signatures in surface water samples collected across the site were remarkably similar (the {delta}{sup 66}Zn, relative to JMC 3-0749-L, for most samples ranged from 0.20 to 0.30 Per-Mille-Sign {+-} 0.09 Per-Mille-Sign 2{sigma}). This probably suggests that the ultimate source of Zn is consistent across the Waldorf site, regardless of the metal loading pathway. The {delta}{sup 66}Zn of pore water samples collected within a nearby metal-impacted wetland area, however, were more variable, ranging from 0.20 to 0.80 Per-Mille-Sign {+-} 0.09 Per-Mille-Sign 2{sigma}. Here the Zn isotopes seemed to reflect differences in groundwater flow pathways. However, a host of secondary processes might also have impacted Zn isotopes, including adsorption of Zn onto soil components, complexation of Zn with dissolved organic matter, uptake of Zn into plants, and the precipitation of Zn during the formation of reduced sulfur species. Zinc isotope analysis proved useful in this study; however, the utility of this isotopic tool would improve considerably with the addition of a comprehensive experimental foundation for interpreting the complex isotopic relationships found in

  2. Oxidation of CO and surface properties of well characterized Pt{sub 3}Sn bimetallic alloy surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Stamenkovic, V.; Arenz, M.; Blizanac, B. B.; Ross, P. N.; Markovic, N. M. [University of California-Berkeley, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA (United States)

    2004-04-01

    The Pt{sub 3}Sn alloy is known to be one of the most active systems for carbon monoxide oxidation. This paper continues the effort begun earlier to explore the link between macroscopic level properties of the Pt{sub 3}Sn(hkl) surfaces in an electrochemical environment and in-situ atomic level characterization. Specifically, the work reported here entails a further examination of the Pt{sub 3}Sn(110) interface in an electrochemical environment as part of a detailed study of structural effects on electrocatalysis. Alloy surfaces have been characterized in ultra-high vacuum (UHV) by Auger electron microscopy, low energy ion scattering spectroscopy (LEISS) and low energy electron diffraction (LEED). Surface electrochemistry of carbon monoxide was studied in-situ by Fourier transform infrared (FTIR) spectroscopy. Result showed that in contrast to the Pt{sub 3}Sn(111) surface, changes in band morphology and vibrational properties are clearly absent on the Pt{sub 3}Sn(110) surface. In the case of the Pt{sub 3}Sn(hkl)-CO interaction, not only electronic effects, but also other factors, such as surface structure and intermolecular repulsion between adsorbed CO species were found to be responsible for high catalytic activity. 40 refs., 6 figs.

  3. Surface Casing Pressure As an Indicator of Well Integrity Loss and Stray Gas Migration in the Wattenberg Field, Colorado.

    Science.gov (United States)

    Lackey, Greg; Rajaram, Harihar; Sherwood, Owen A; Burke, Troy L; Ryan, Joseph N

    2017-03-01

    The risk of environmental contamination by oil and gas wells depends strongly on the frequency with which they lose integrity. Wells with compromised integrity typically exhibit pressure in their outermost annulus (surface casing pressure, SfCP) due to gas accumulation. SfCP is an easily measured but poorly documented gauge of well integrity. Here, we analyze SfCP data from the Colorado Oil and Gas Conservation Commission database to evaluate the frequency of well integrity loss in the Wattenberg Test Zone (WTZ), within the Wattenberg Field, Colorado. Deviated and horizontal wells were found to exhibit SfCP more frequently than vertical wells. We propose a physically meaningful well-specific critical SfCP criterion, which indicates the potential for a well to induce stray gas migration. We show that 270 of 3923 wells tested for SfCP in the WTZ exceeded critical SfCP. Critical SfCP is strongly controlled by the depth of the surface casing. Newer horizontal wells, drilled during the unconventional drilling boom, exhibited critical SfCP less frequently than other wells because they were predominantly constructed with deeper surface casings. Thus, they pose a lower risk for inducing stray gas migration than legacy vertical or deviated wells with surface casings shorter than modern standards.

  4. Surface Structure Dependence of SO 2 Interaction with Ceria Nanocrystals with Well-Defined Surface Facets

    Energy Technology Data Exchange (ETDEWEB)

    Tumuluri, Uma; Li, Meijun; Cook, Brandon G.; Sumpter, Bobby; Dai, Sheng; Wu, Zili

    2015-12-31

    The effects of the surface structure of ceria (CeO2) on the nature, strength, and amount of species resulting from SO2 adsorption were studied using in situ IR and Raman spectroscopies coupled with mass spectrometry, along with first-principles calculations based on density functional theory (DFT). CeO2 nanocrystals with different morphologies, namely, rods (representing a defective structure), cubes (100 facet), and octahedra (111 facet), were used to represent different CeO2 surface structures. IR and Raman spectroscopic studies showed that the structure and binding strength of adsorbed species from SO2 depend on the shape of the CeO2 nanocrystals. SO2 adsorbs mainly as surface sulfites and sulfates at room temperature on CeO2 rods, cubes, and octahedra that were either oxidatively or reductively pretreated. The formation of sulfites is more evident on CeO2 octahedra, whereas surface sulfates are more prominent on CeO2 rods and cubes. This is explained by the increasing reducibility of the surface oxygen in the order octahedra < cubes < rods. Bulk sulfites are also formed during SO2 adsorption on reduced CeO2 rods. The formation of surface sulfites and sulfates on CeO2 cubes is in good agreement with our DFT results of SO2 interactions with the CeO2(100) surface. CeO2 rods desorb SO2 at higher temperatures than cubes and octahedra nanocrystals, but bulk sulfates are formed on CeO2 rods and cubes after high-temperature desorption whereas only some surface sulfates/sulfites are left on octahedra. This difference is rationalized by the fact that CeO2 rods have the highest surface basicity and largest amount of defects among the three nanocrystals, so they bind and react with SO2 strongly and are the most degraded after SO2 adsorption cycles. The fundamental understanding obtained in this work on the effects of the surface structure and defects on the interaction of SO2 with CeO2 provides insights for the design of more sulfur-resistant CeO2-based catalysts.

  5. Determination of Granite Rock Massif Weathering and Cracking of Surface Layers in the Oldest Parts of Medieval Mine Depending on Used Mining Method

    Science.gov (United States)

    Lednická, Markéta; Kaláb, Zdeněk

    2016-06-01

    The paper presents the use of selected non-destructive testing methods for the purpose of specifying information on weathering and cracking of surface layers of granite rock massif in the medieval Jeroným Mine (the Czech Republic). This mine has been declared the National Heritage Site of the Czech Republic and its opening as a mining museum to the public is gradually prepared. Geological and geomechanical evaluation documents the possibility to find all kinds of weathering grades of rock massif in this mine. Two non-destructive methods have been tested, namely the measurement of ultrasonic pulse velocity and the measurement of Schmidt hammer rebound value. Field measurements were performed in two selected galleries to verify the application of such methods in specific conditions of underground spaces. Used mining method is one of the parameters later influencing cracking of rock massif. In selected galleries, two different mining methods were used which means that a part of a gallery profile was mined out by hand tools in the Middle Ages and another part of the profile was later mined out by blasting. Measurements in these galleries have enabled to analyse the influence of used mining methods on cracking of rock massif in the impaired zone, and, consequently, on ongoing weathering processes in those zones.

  6. CO2 Electroreduction on Well-Defined Bimetallic Surfaces

    DEFF Research Database (Denmark)

    Varela Gasque, Ana Sofia; Schlaup, Christian Georg; Jovanov, Zarko P.

    2013-01-01

    We have studied the electrochemical reduction of CO2 on Cu overlayers on Pt(111) and Pt(211) surfaces. These systems were chosen to investigate the effect of strain on the catalytic activity of Cu surfaces and to obtain information about the role of steps in this process. The selectivity toward h...

  7. 塔里木盆地沙雅隆起星火1井寒武系烃源岩特征%Characteristics of Cambrian source rocks in well XH1, Shaya Uplift, Tarim Basin

    Institute of Scientific and Technical Information of China (English)

    朱传玲; 闫华; 云露; 韩强; 马慧明

    2014-01-01

    在对塔里木盆地北部星火1井寒武系玉尔吐斯组灰黑、黑色碳质泥岩进行一系列有机地球化学特征测试分析的基础上,从有机碳、氯仿沥青“A”、生烃潜量、热解峰温、海相镜状体反射率、烃源岩可溶抽提物和饱和烃色质特征等方面着手,对该烃源岩的有机质丰度、成熟度及类型进行分析。结合前人研究成果,讨论了这套烃源岩与以往报道的寒武系烃源岩的异同,并开展了与塔河原油的油-岩对比分析。结果表明,该套烃源岩有机质丰度高,而且已达高成熟热演化阶段,与柯坪露头肖尔布拉克剖面下寒武统玉尔吐斯组烃源岩特征类似;星火1井下寒武统黑色碳质页岩有机质地化特征与塔河油田原油具亲源性。%In the northwestern Shaya Uplift of the Tarim Basin, gray and black carbonaceous mudstones were collected from the Cambrian Yuertusi Formation in the well XH1, and were tested for organic geochemistry. The analyses included the determinations of organic carbon (TOC), chloroform bitumen “A”, hydrocarbon generation potential, pyrolysis peak temperature, marine vitrinite, soluble extraction of source rock, gas chromatography and so on. The organic matter abundance, maturity and type of source rocks were studied. The Cambrian source rocks in the well XH1 were compared with other Cambrian source rocks in previous reports. Oil-source correlation of the studied source rocks was made compared to those from the Tahe oilfield. The studied source rocks have high organic matter abundance, and have entered the high-mature stage for thermal evolution, which is similar with the source rocks in the Lower Cambrian Yuertusi Formation on the Xiaoerbulak profile in the Keping area. There are some similar geochemical characteristics between the Lower Cambrian black carbonaceous shale and the crude oil from the Tahe oilfield.

  8. A large rock avalanche onto Morsarjökull glacier, south-east Iceland. Its implications for ice-surface evolution and glacier dynamics

    OpenAIRE

    Decaulne, Armelle; Sæmundsson, Þorsteinn; Pétursson, Halldór G.; Jónsson, Helgi Pall; Sigurðsson, Ingvar A.

    2010-01-01

    In spring 2007, a large rock avalanche descended onto the Morsárjökull valley glacier in southeast Iceland, leaving one fifth of the glacier buried. The insulating effect of the deposit on the ice was quickly observed as a difference in the ablation between the exposed ice and that under the deposit. After three melt seasons, the ice surface under the deposit was 29 m above the surrounding glacier surface. A reduced rate of ice melting beneath the area of the deposit would likely alter the lo...

  9. How well Can We Classify SWOT-derived Water Surface Profiles?

    Science.gov (United States)

    Frasson, R. P. M.; Wei, R.; Picamilh, C.; Durand, M. T.

    2015-12-01

    The upcoming Surface Water Ocean Topography (SWOT) mission will detect water bodies and measure water surface elevation throughout the globe. Within its continental high resolution mask, SWOT is expected to deliver measurements of river width, water elevation and slope of rivers wider than ~50 m. The definition of river reaches is an integral step of the computation of discharge based on SWOT's observables. As poorly defined reaches can negatively affect the accuracy of discharge estimations, we seek strategies to break up rivers into physically meaningful sections. In the present work, we investigate how accurately we can classify water surface profiles based on simulated SWOT observations. We assume that most river sections can be classified as either M1 (mild slope, with depth larger than the normal depth), or A1 (adverse slope with depth larger than the critical depth). This assumption allows the classification to be based solely on the second derivative of water surface profiles, with convex profiles being classified as A1 and concave profiles as M1. We consider a HEC-RAS model of the Sacramento River as a representation of the true state of the river. We employ the SWOT instrument simulator to generate a synthetic pass of the river, which includes our best estimates of height measurement noise and geolocation errors. We process the resulting point cloud of water surface heights with the RiverObs package, which delineates the river center line and draws the water surface profile. Next, we identify inflection points in the water surface profile and classify the sections between the inflection points. Finally, we compare our limited classification of simulated SWOT-derived water surface profile to the "exact" classification of the modeled Sacramento River. With this exercise, we expect to determine if SWOT observations can be used to find inflection points in water surface profiles, which would bring knowledge of flow regimes into the definition of river reaches.

  10. Recognition method for volcanic rock facies by well logging%利用测井方法识别火山岩岩相方法

    Institute of Scientific and Technical Information of China (English)

    张程恩; 潘保芝; 王飞; 边会媛; 韩雪; 陈刚

    2011-01-01

    利用实际岩石薄片数据及测井数据,通过GR-TH及GR-AC交会图方法将松南气田营城组岩石 结构划分为熔岩结构、熔结结构和凝灰结构3种.凝灰结构和熔结结构对应爆发相,熔岩结构对应喷溢相.结合次生孔隙度的大小及岩心、录井信息对出现的6种亚相:热碎屑流亚相、热基浪亚相、空落亚相、上部亚相、中部亚相和下部亚相进一步划分,其结果与地质上的岩相亚相基本一致.%Using actual rock slices and logging data, the rock structures of Yingcheng Formation in Songnan gas field was divided into lava, welding and tuff structures by the cross plots of GR-TH and GR-AC. Tuff and welding structures correspond to explosive facies, while lava structure corresponds to extrusive facies. The six different subfacies (thermal debris flow, thermal base surge, airfall, upper, middle and lower subfacies) recognized by secondary porosity, core and logging data show a high accuracy compared with the actual geological results.

  11. In situ stress magnitude and rock strength in the Nankai accretionary complex: a novel approach using paired constraints from downhole data in two wells

    Science.gov (United States)

    Huffman, K. A.; Saffer, D. M.; Dugan, B.

    2016-07-01

    We present a method to simultaneously constrain both far-field horizontal stress magnitudes ( S hmin and S Hmax) and in situ rock unconfined compressive strength (UCS), using geophysical logging data from two boreholes located 70 m apart that access the uppermost accretionary prism of the Nankai subduction zone . The boreholes sample the same sediments and are affected by the same tectonic stress field, but were drilled with different annular pressures, thus providing a unique opportunity to refine estimates of both in situ stress magnitudes and rock strength. We develop a forward model to predict the angular width of compressional wellbore failures (borehole breakouts), and identify combinations of S Hmax and UCS that best match breakout widths observed in resistivity images from the two boreholes. The method requires knowledge of S hmin, which is defined by leak-off tests conducted during drilling. Our results define a normal to strike-slip stress regime from 900 to 1386 m below seafloor, consistent with observations from seismic and core data. Our analysis also suggests that in situ values of UCS are generally slightly lower that commonly assumed on the basis of published empirical relations between UCS and P-wave velocity.

  12. Droplet nucleation on a well-defined hydrophilic-hydrophobic surface of 10 nm order resolution.

    Science.gov (United States)

    Yamada, Yutaka; Ikuta, Tatsuya; Nishiyama, Takashi; Takahashi, Koji; Takata, Yasuyuki

    2014-12-01

    Water condensation on a hybrid hydrophilic-hydrophobic surface was investigated to reveal nucleation mechanisms at the microscale. Focused ion beam (FIB) irradiation was used to change the wettability of the hydrophobic surface with 10 nm order spatial resolution. Condensation experiments were conducted using environmental scanning electron microscopy; droplets, with a minimum diameter of 800 nm, lined up on the FIB-irradiated hydrophilic lines. The heterogeneous nucleation theory was extended to consider the water molecules attracted to the hydrophilic area, thereby enabling explanation of the nucleation mechanism under unsaturated conditions. Our results showed that the effective surface coverage of the water molecules on the hydrophilic region was 0.1-1.1 at 0.0 °C and 560 Pa and was dependent on the width of the FIB-irradiated hydrophilic lines and hydrophobic area. The droplet nucleation mechanism unveiled in this work would enable the design of new surfaces with enhanced dropwise condensation heat transfer.

  13. Rock Stars

    Institute of Scientific and Technical Information of China (English)

    张国平

    2000-01-01

    Around the world young people are spending unbelievable sums of money to listen to rock music. Forbes Magazine reports that at least fifty rock stars have incomes between two million and six million dollars per year.

  14. Improved Design Tools for Surface Water and Standing Column Well Heat Pump Systems (DE-EE0002961)

    Energy Technology Data Exchange (ETDEWEB)

    Spitler, J. D.; Culling, J. R.; Conjeevaram, K.; Ramesh, M.; Selvakumar, M.

    2012-11-30

    Ground-source heat pump (GSHP) systems are perhaps the most widely used “sustainable” heating and cooling systems, with an estimated 1.7 million installed units with total installed heating capacity on the order of 18 GW. They are widely used in residential, commercial, and institutional buildings. Standing column wells (SCW) are one form of ground heat exchanger that, under the right geological conditions, can provide excellent energy efficiency at a relatively low capital cost. Closed-loop surface water heat pump (SWHP) systems utilize surface water heat exchangers (SWHE) to reject or extract heat from nearby surface water bodies. For building near surface water bodies, these systems also offer a high degree of energy efficiency at a low capital cost. However, there have been few design tools available for properly sizing standing column wells or surface water heat exchangers. Nor have tools for analyzing the energy consumption and supporting economics-based design decisions been available. The main contributions of this project lie in providing new tools that support design and energy analysis. These include a design tool for sizing surface water heat exchangers, a design tool for sizing standing column wells, a new model of surface water heat pump systems implemented in EnergyPlus and a new model of standing column wells implemented in EnergyPlus. These tools will better help engineers design these systems and determine the economic and technical feasibility.

  15. Rock Art

    Science.gov (United States)

    Henn, Cynthia A.

    2004-01-01

    There are many interpretations for the symbols that are seen in rock art, but no decoding key has ever been discovered. This article describes one classroom's experiences with a lesson on rock art--making their rock art and developing their own personal symbols. This lesson allowed for creativity, while giving an opportunity for integration…

  16. Rock Art

    Science.gov (United States)

    Henn, Cynthia A.

    2004-01-01

    There are many interpretations for the symbols that are seen in rock art, but no decoding key has ever been discovered. This article describes one classroom's experiences with a lesson on rock art--making their rock art and developing their own personal symbols. This lesson allowed for creativity, while giving an opportunity for integration…

  17. Rock Finding

    Science.gov (United States)

    Rommel-Esham, Katie; Constable, Susan D.

    2006-01-01

    In this article, the authors discuss a literature-based activity that helps students discover the importance of making detailed observations. In an inspiring children's classic book, "Everybody Needs a Rock" by Byrd Baylor (1974), the author invites readers to go "rock finding," laying out 10 rules for finding a "perfect" rock. In this way, the…

  18. Advanced Rock Drilling Technologies Using High Laser Power

    Science.gov (United States)

    Buckstegge, Frederik; Michel, Theresa; Zimmermann, Maik; Roth, Stephan; Schmidt, Michael

    Drilling through hard rock formations causes high mechanical wear and most often environmental disturbance. For the realization of an Advanced Adiabatic Compressed Air Energy Storage (AA-CAES) power plant a new and efficient method for tunneling utilising laser technology to support mechanical ablation of rock formations will be developed. Laser irradiation of inhomogeneous rock surfaces causes irregular thermal expansion leading to the formation of cracks and splintering as well as melting and slag-formation. This study focuses on the interaction of laser irradiation with calcite, porphyrite and siderite rock formations. A high power disc laser system at 1030nm wavelength is used to investigate the specific energy necessary to remove a unit volume depending on interaction times and applied power. Specific energies have been measured and an increase of fragility and brittleness of the rock surface has been observed.

  19. Fabrication of large-sized two-dimensional ordered surface array with well-controlled structure via colloidal particle lithography.

    Science.gov (United States)

    Meng, Xiaohui; Zhang, Xinping; Ye, Lei; Qiu, Dong

    2014-06-17

    Epoxy resin coated glass slides were used for colloidal particle lithography, in order to prepare well-defined 2D surface arrays. Upon the assistance of a large-sized 2D colloidal single crystal as template, centimeter-sized ordered surface arrays of bowl-like units were obtained. Systematic studies revealed that the parameters of obtained surface arrays could be readily controlled by some operational factors, such as temperature, epoxy resin layer thickness, and template particle size. With epoxy resin substituting for normal linear polymer, the height/diameter ratio of bowls in the formed surface arrays can be largely increased. With further reactive plasma etching, the parameters of ordered surface arrays could be finely tuned through controlling etching time. This study provides a facile way to prepare large-sized 2D surface arrays with tunable parameters.

  20. Numerical simulation for rheological characteristics of alternating distribution of soft and hard rock layers

    Institute of Scientific and Technical Information of China (English)

    HAN Bing; WANG Zhi-yin; DING Xiu-li; XU Ping

    2006-01-01

    The difficulty of selecting appropriate rheological model and parameters for the alternating distribution of soft and hard rock layers was often encountered due to the unhomogeneity, discontinuity and anisotropy of rock mass. The Burgers and generalized Kelvin models were applied to the soft and hard rock respectively and the rheological parameters were obtained based on the method of optimum separation. By using the simulated code FLAC3D, the stability of surrounding rocks of a certain underground plant was analyzed. The effect of surface load and weakening the parameters intensity of argillaceous and bioclastic interlayers between soft and hard rock on rheological behavior of layer composite rock mass was investigated. The results indicate that the rheological characteristics of soft and hard rock layer in composite rock mass can be described well with above two rheological models.

  1. Increasing the Detection Limit of the Parkinson Disorder through a Specific Surface Chemistry Applied onto Inner Surface of the Titration Well

    Directory of Open Access Journals (Sweden)

    Fabienne Poncin-Epaillard

    2012-04-01

    Full Text Available The main objective of this paper was to illustrate the enhancement of the sensitivity of ELISA titration for neurodegenerative proteins by reducing nonspecific adsorptions that could lead to false positives. This goal was obtained thanks to the association of plasma and wet chemistries applied to the inner surface of the titration well. The polypropylene surface was plasma-activated and then, dip-coated with different amphiphilic molecules. These molecules have more or less long hydrocarbon chains and may be charged. The modified surfaces were characterized in terms of hydrophilic—phobic character, surface chemical groups and topography. Finally, the coated wells were tested during the ELISA titration of the specific antibody capture of the α-synuclein protein. The highest sensitivity is obtained with polar (Θ = 35°, negatively charged and smooth inner surface.

  2. New constraints on the subsurface geology of the Mexico City Basin: The San Lorenzo Tezonco deep well, on the basis of 40Ar/39Ar geochronology and whole-rock chemistry

    Science.gov (United States)

    Arce, J. L.; Layer, P. W.; Morales-Casique, E.; Benowitz, J. A.; Rangel, E.; Escolero, O.

    2013-10-01

    The San Lorenzo Tezonco deep well, drilled in 2012 by "Sistema de Aguas de la Ciudad de México" (Water Supply System of Mexico City) in the Mexico Basin to a depth of 2008 m, offers an excellent opportunity to explore the subsurface stratigraphy and general geology of the region. Unfortunately, only chipped samples from this well were recovered, which were examined and analyzed for whole-rock chemistry, 40Ar/39Ar, and U-Pb zircon geochronology, in order to reconstruct the lithology of the well. Contrary to previous deep wells of the Mexico Basin, no basement sedimentary rocks were found in this one. While the upper 70 m are composed of lacustrine sediments associated with Lake Texcoco, volcanic rocks make up the majority of the well and range in age from more than 18 Ma to 0.25 Ma. Andesitic lavas are the most abundant products of the stratigraphic column, followed by acidic products represented by dacitic and rhyolitic lavas and ignimbrite deposits. Less abundant are basaltic andesite lavas appearing in the upper and lower parts of the column. The thickest sequence of the well is represented not only by Miocene volcanic rocks ranging from 5 to 17 Ma, suggesting a period of intense volcanic activity in this area producing mainly andesitic lavas, but also by thick rhyolitic ignimbrite deposits dated at 5 Ma. These deposits suggest the presence of a caldera structure, probably buried by subsequent volcanic products and lacustrine sediments. Trace element concentrations suggest that volcanism is likely produced in a subduction environment with typical negative anomalies of Nb, Ta, Ti, and P and positive anomalies in Pb and Cs. We correlated the well units with units outcropping in mountain ranges in the surrounding area, with the recognition of the following units or formations: Eocene Andesite, San Nicolás Basaltic Andesite, Tepoztlán Formation, Miocene Volcanism, Sierra de las Cruces, and Chichinautzin Volcanic Field products. By correlating the two closest deep

  3. Research on forced gas draining from coal seams by surface well drilling

    Institute of Scientific and Technical Information of China (English)

    Wu Dongmei; Wang Haifeng; Ge Chungui; An Fenghua

    2011-01-01

    Surface drilling was performed at the Luling Coal Mine, in Huaibei, to shorten the period required for gas draining. The experimental study was designed to reduce the cost of gas control by efficiently draining gas from the upper protected layer. The structural arraignment and technical principles of pressure relief via surface drilling are discussed. Results from the trial showed that gas drained from the surface system over a period of 10 months. The total amount of collected gas was 248.4 million m3. The gas draining occurred in three stages: a growth period; a period of maximum gas production; and an attenuation period. The period of maximum gas production lasted for 4 months. During this time the methane concentration ranged from 60% to 90% and the average draining rate was 10.6 m3/min. Combined with other methods of draining it was possible to drain 70.6% of the gas from middle coal seam groups. The amount of residual gas dropped to 5.2 m3/ton, and the pressure of the residual gas fell to 0.53 MPa,thereby eliminating the outburst danger in the middle coal seam groups. The factors affecting pressure relief gas draining by surface drilling were analysed.

  4. Vulnerability of drinking-water wells in La Crosse, Wisconsin, to enteric-virus contamination from surface water contributions

    Science.gov (United States)

    Borchardt, M. A.; Haas, N.L.; Hunt, R.J.

    2004-01-01

    Human enteric viruses can contaminate municipal drinking-water wells, but few studies have examined the routes by which viruses enter these wells. In the present study, the objective was to monitor the municipal wells of La Crosse, Wisconsin, for enteric viruses and determine whether the amount of Mississippi River water infiltrating the wells was related to the frequency of virus detection. From March 2001 to February 2002, one river water site and four wells predicted by hydrogeological modeling to have variable degrees of surface water contributions were sampled monthly for enteric viruses, microbial indicators of sanitary quality, and oxygen and hydrogen isotopes. 18O/ 16O and 2H/1H ratios were used to determine the level of surface water contributions. All samples were collected prior to chlorination at the wellhead. By reverse transcription-PCR (RT-PCR), 24 of 48 municipal well water samples (50%) were positive for enteric viruses, including enteroviruses, rotavirus, hepatitis A virus (HAV), and noroviruses. Of 12 river water samples, 10 (83%) were virus positive by RT-PCR. Viable enteroviruses were not detected by cell culture in the well samples, although three well samples were positive for culturable HAV. Enteroviruses detected in the wells by RT-PCR were identified as several serotypes of echoviruses and group A and group B coxsackieviruses. None of the well water samples was positive for indicators of sanitary quality, namely male-specific and somatic coliphages, total coliform bacteria, Escherichia coli, and fecal enterococci. Contrary to expectations, viruses were found in all wells regardless of the level of surface water contributions. This result suggests that there were other unidentified sources, in addition to surface water, responsible for the contamination.

  5. How well will the Surface Water and Ocean Topography (SWOT) mission observe global reservoirs?

    Science.gov (United States)

    Solander, Kurt C.; Reager, John T.; Famiglietti, James S.

    2016-03-01

    Accurate observations of global reservoir storage are critical to understand the availability of managed water resources. By enabling estimates of surface water area and height for reservoir sizes exceeding 250 m2 at a maximum repeat orbit of up to 21 days, the NASA Surface Water and Ocean Topography (SWOT) satellite mission (anticipated launch date 2020) is expected to greatly improve upon existing reservoir monitoring capabilities. It is thus essential that spatial and temporal measurement uncertainty for water bodies is known a priori to maximize the utility of SWOT observations as the data are acquired. In this study, we evaluate SWOT reservoir observations using a three-pronged approach that assesses temporal aliasing, errors due to specific reservoir spatial properties, and SWOT performance over actual reservoirs using a combination of in situ and simulated reservoir observations from the SWOTsim instrument simulator. Results indicate temporal errors to be less than 5% for the smallest reservoir sizes (100 km2). Surface area and height errors were found to be minimal (area SWOT, this study will be have important implications for future applications of SWOT reservoir measurements in global monitoring systems and models.

  6. Dielectric coating and surface plasmon enhancement of multi-color quantum-well structures

    DEFF Research Database (Denmark)

    Fadil, Ahmed; Iida, Daisuke; Ou, Yiyu

    We fabricate a multi-colored quantum-well structure as a prototype towards monolithic white light-emitting diodes, and modify the emission intensities of different colors by introducing dielectric and Ag nanoparticle coating.......We fabricate a multi-colored quantum-well structure as a prototype towards monolithic white light-emitting diodes, and modify the emission intensities of different colors by introducing dielectric and Ag nanoparticle coating....

  7. In-Situ and Experimental Evidence for Acidic Weathering of Rocks and Soils on Mars

    Science.gov (United States)

    Hurowitz, J. A.; McLennan, S. M.; Tosca, N. J.; Arvidson, R. E.; Michalski, J. R.; Ming, D.; Schroeder, C.; Squyres, S. W.

    2006-01-01

    Experimental data for alteration of synthetic Martian basalts at pH=0-1 indicate that chemical fractionations at low pH are vastly different from those observed during terrestrial weathering. Rock analyses from Gusev crater are well described by the relationships apparent from low pH experimental alteration data. A model for rock surface alteration is developed which indicates that a leached alteration zone is present on rock surfaces at Gusev. This zone is not chemically fractionated to a large degree from the underlying rock interior, indicating that the rock surface alteration process has occurred at low fluid-to-rock ratio. The geochemistry of natural rock surfaces analyzed by APXS is consistent with a mixture between adhering soil/dust and the leached alteration zone. The chemistry of rock surfaces analyzed after brushing with the RAT is largely representative of the leached alteration zone. The chemistry of rock surfaces analyzed after grinding with the RAT is largely representative of the interior of the rock, relatively unaffected by the alteration process occurring at the rock surface. Elemental measurements from the Spirit, Opportunity, Pathfinder and Viking 1 landing sites indicate that soil chemistry from widely separated locations is consistent with the low-pH, low fluid to rock ratio alteration relationships developed for Gusev rocks. Soils are affected principally by mobility of FeO and MgO, consistent with alteration of olivine-bearing basalt and subsequent precipitation of FeO and MgO bearing secondary minerals as the primary control on soil geochemistry.

  8. Surface Reaction Kinetics of Steam- and CO2-Reforming as Well as Oxidation of Methane over Nickel-Based Catalysts

    OpenAIRE

    Karla Herrera Delgado; Lubow Maier; Steffen Tischer; Alexander Zellner; Henning Stotz; Olaf Deutschmann

    2015-01-01

    An experimental and kinetic modeling study on the Ni-catalyzed conversion of methane under oxidative and reforming conditions is presented. The numerical model is based on a surface reaction mechanism consisting of 52 elementary-step like reactions with 14 surface and six gas-phase species. Reactions for the conversion of methane with oxygen, steam, and CO2 as well as methanation, water-gas shift reaction and carbon formation via Boudouard reaction are included. The mechanism is implemented i...

  9. Investigation of the occurrence of pesticide residues in rural wells and surface water following application to tobacco

    Directory of Open Access Journals (Sweden)

    Edson C. Bortoluzzi

    2007-01-01

    Full Text Available In this work the exposure of wells and surface water to pesticides, commonly used for tobacco cropping, was assessed. Water consumption wells and surface water flows were sampled at different times. After a preconcentration step with solid phase extraction (SPE, the selected pesticides were determined by gas chromatography with electron capture detection (GC-ECD or high performance liquid chromatography with diode array detection (HPLC-DAD. No pesticides were detected in the well water samples and surface water flow in the winter season. However, in the spring and summer higher concentrations of chlorpyrifos and imidacloprid were found in the water source samples. Atrazine, simazine and clomazone were also found. The occurrence of pesticides in collected water samples was related with the application to tobacco.

  10. Transport and Deposition of Nanoparticles in the Pore Network of a Reservoir Rock: Effects of Pore Surface Heterogeneity and Radial Diffusion

    Science.gov (United States)

    Pham, Ngoc; Papavassiliou, Dimitrios

    2014-03-01

    In this study, transport behavior of nanoparticles under different pore surface conditions of consolidated Berea sandstone is numerically investigated. Micro-CT scanning technique is applied to obtain 3D grayscale images of the rock sample geometry. Quantitative characterization, which is based on image analysis is done to obtain physical properties of the pore network, such as the pore size distribution and the type of each pore (dead-end, isolated, and fully connected pore). Transport of water through the rock is simulated by employing a 3D lattice Boltzmann method. The trajectories of nanopaticles moving under convection in the simulated flow field and due to molecular diffusion are monitored in the Lagrangian framework. It is assumed in the model that the particle adsorption on the pore surface, which is modeled as a pseudo-first order adsorption, is the only factor hindering particle propagation. The effect of pore surface heterogeneity to the particle breakthrough is considered, and the role of particle radial diffusion is also addressed in details. The financial support of the Advanced Energy Consortium (AEC BEG08-022) and the computational support of XSEDE (CTS090017) are acknowledged.

  11. Combining surface plasmonic and light extraction enhancement on InGaN quantum-well light-emitters

    DEFF Research Database (Denmark)

    Fadil, Ahmed; Ou, Yiyu; Iida, Daisuke

    2016-01-01

    Surface plasmon coupling with light-emitters and surface nano-patterning have widely been used separately to improve low efficiency InGaN light-emitting diodes. We demonstrate a method where dielectric nano-patterning and Ag nanoparticles (NPs) are combined to provide both light extraction...... and internal quantum efficiency enhancement for InGaN/GaN quantum-well light-emitters. By fabricating dielectric nano-rod pattern on the GaN surface, an optical coating that improves the light extraction is obtained, and furthermore has a low refractive index which blue-shifts the plasmonic resonance of Ag NPs...

  12. InGaAs Quantum Well Grown on High-Index Surfaces for Superluminescent Diode Applications.

    Science.gov (United States)

    Li, Zhenhua; Wu, Jiang; Wang, Zhiming M; Fan, Dongsheng; Guo, Aqiang; Li, Shibing; Yu, Shui-Qing; Manasreh, Omar; Salamo, Gregory J

    2010-04-22

    The morphological and optical properties of In0.2Ga0.8As/GaAs quantum wells grown on various substrates are investigated for possible application to superluminescent diodes. The In0.2Ga0.8As/GaAs quantum wells are grown by molecular beam epitaxy on GaAs (100), (210), (311), and (731) substrates. A broad photoluminescence emission peak (~950 nm) with a full width at half maximum (FWHM) of 48 nm is obtained from the sample grown on (210) substrate at room temperature, which is over four times wider than the quantum well simultaneously grown on (100) substrate. On the other hand, a very narrow photoluminescence spectrum is observed from the sample grown on (311) with FWHM = 7.8 nm. The results presented in this article demonstrate the potential of high-index GaAs substrates for superluminescent diode applications.

  13. InGaAs Quantum Well Grown on High-Index Surfaces for Superluminescent Diode Applications

    Directory of Open Access Journals (Sweden)

    Wu Jiang

    2010-01-01

    Full Text Available Abstract The morphological and optical properties of In0.2Ga0.8As/GaAs quantum wells grown on various substrates are investigated for possible application to superluminescent diodes. The In0.2Ga0.8As/GaAs quantum wells are grown by molecular beam epitaxy on GaAs (100, (210, (311, and (731 substrates. A broad photoluminescence emission peak (~950 nm with a full width at half maximum (FWHM of 48 nm is obtained from the sample grown on (210 substrate at room temperature, which is over four times wider than the quantum well simultaneously grown on (100 substrate. On the other hand, a very narrow photoluminescence spectrum is observed from the sample grown on (311 with FWHM = 7.8 nm. The results presented in this article demonstrate the potential of high-index GaAs substrates for superluminescent diode applications.

  14. Influence of a single lightning discharge on the intensity of an air electric field and acoustic emission of near-surface rocks

    Directory of Open Access Journals (Sweden)

    S. E. Smirnov

    2012-10-01

    Full Text Available The effect was observed as a sharp fall of the electric potential gradient from +80 V m−1 down to –21 V m−1. After that the field returned to its normal level according to the formula of the capacitor discharge with 17 s characteristic time. Simultaneously, the response of the acoustic emission of surface rocks in the range of frequencies between 6.5 kHz and 11 kHz was evaluated.

  15. Infiltration of pesticides in surface water into nearby drinking water supply wells

    DEFF Research Database (Denmark)

    Malaguerra, Flavio; Albrechtsen, Hans-Jørgen; Binning, Philip John

    data of a tracer experiment in a riparian zone. Three compounds were considered: an older pesticide MCPP (Mecoprop) which is mobile and persistent, glyphosate (Roundup), a new biodegradable and strongly sorbed pesticide, and its degradation product AMPA. Global sensitivity analysis using the method...... water. Global sensitivity analysis results were compared with rank correlation statistics between pesticide concentrations and geological parameters derived from a comprehensive database of Danish drinking water wells. Aquitard thickness and well depth are the most critical parameters in both the model...

  16. Energy analysis for damage and catastrophic failure of rocks

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The development history and current state of studies on the characteristics and mechanisms of deformation and failure of rock materials were briefly reviewed from the viewpoint of energy.The main scope and the achievable objectives of the energy-based research system were expatiated.It was validated by experiments that the damage process of rocks can be well described by the rock damage evolution equation established based on energy dissipation.It was found from the uniaxial compression and biaxial compression tests that only a small proportion of the total input energy in hard rocks is dissipated before peak load and a large proportion in soft rocks is dissipated before peak load.For both hard and soft rocks,the energy dissipated after peak load accounts for a greater proportion.More energy would be required for rock failure under equal biaxial compression than under unequal biaxial compression.The total absorbed energy is different for rock failure under high-rate loading and low-rate loading.More fragmented failure pattern usually corresponds to higher energy absorption.The mesoscopic analysis on the damage and failure of bedded salt rocks showed that the energy dissipation is prominent and the total absorbed energy for rock failure is low when cracks propagate in the weak mud interlayer while it is contrary when cracks propagate in the salt rock.The energy accumulation,transfer,dissipation and release during the failure process of tunnel with impending failure under disturbance were analyzed theoretically based on the elastoplastic mechanics theory.Furthermore,the spatial distribution of energy dissipation and energy release of fractured rocks under unloading was simulated numerically.It was demonstrated that energy is likely to be released from the weakest surface under compression,which triggers the global failure of rocks.

  17. 'Earhart' Rock

    Science.gov (United States)

    2004-01-01

    This false-color image taken by NASA's Mars Exploration Rover Opportunity shows a rock informally named 'Earhart' on the lower slopes of 'Endurance Crater.' The rock was named after the pilot Amelia Earhart. Like 'Escher' and other rocks dotting the bottom of Endurance, scientists believe fractures in Earhart could have been formed by one of several processes. They may have been caused by the impact that created Endurance Crater, or they might have arisen when water leftover from the rock's formation dried up. A third possibility is that much later, after the rock was formed, and after the crater was created, the rock became wet once again, then dried up and developed cracks. Rover team members do not have plans to investigate Earhart in detail because it is located across potentially hazardous sandy terrain. This image was taken on sol 219 (Sept. 4) by the rover's panoramic camera, using its 750-, 530- and 430-nanometer filters.

  18. Rock blocks

    OpenAIRE

    Turner, W.

    2007-01-01

    Consider representation theory associated to symmetric groups, or to Hecke algebras in type A, or to q-Schur algebras, or to finite general linear groups in non-describing characteristic. Rock blocks are certain combinatorially defined blocks appearing in such a representation theory, first observed by R. Rouquier. Rock blocks are much more symmetric than general blocks, and every block is derived equivalent to a Rock block. Motivated by a theorem of J. Chuang and R. Kessar in the case of sym...

  19. Performance of PRD Welled Surfaces in T Shape Noise Barriers for Controlling Environmental Noise

    Directory of Open Access Journals (Sweden)

    S Momen Bellah

    2010-07-01

    Full Text Available "n "n "nBackgrounds and Objectives: There is a considerable notice in the use of noise barriers in recent years. Noise barriers as a control noise solution can increase the insertion loss to protect receivers. This paper presents the results of an investigation about the acoustic efficiency of primitive root sequence diffuser (PRD on environmental single T-shape barrier."nMaterials and Methods: A 2D boundary element method (BEM is used to predict the insertion loss of the tested barriers. The results of rigid and with quadratic residue diffuser (QRD coverage are also predicted for comparison."nResults: It is found that decreasing the design frequency of PRD shifts the frequency effects towards lower frequencies, and therefore the overall A-weighted insertion loss is improved. It is also found that using wire mesh with reasonably efficient resistivity on the top surface of PRD improves the efficiency of the reactive barriers; however utilizing wire meshes with flow resistivity higher than specific acoustic impedance of air on the PRD top of a diffuser barrier significantly reduces the performance of the barrier within the frequency bandwidth of the diffuser. The performance of PRD covered T-shape barrier at 200 Hz was found to be higher than that of its equivalent QRD barriers in both the far field and areas close to the ground. The amount of improvement compared made by PRD barrier compared with its equivalent rigid barrier at far field is about 2 to 3 dB, while this improvement relative to barrier model .QR4. can reach up to 4- 6 dB."nConclusion: Employing PRD on the top surface of T-shape barrier is found to improve the performance of barriers compared with using rigid and QRD coverage at the examined receiver locations.

  20. AURORA: A FORTRAN program for modeling well stirred plasma and thermal reactors with gas and surface reactions

    Energy Technology Data Exchange (ETDEWEB)

    Meeks, E.; Grcar, J.F.; Kee, R.J. [Sandia National Labs., Livermore, CA (United States). Thermal and Plasma Processes Dept.; Moffat, H.K. [Sandia National Labs., Albuquerque, NM (United States). Surface Processing Sciences Dept.

    1996-02-01

    The AURORA Software is a FORTRAN computer program that predicts the steady-state or time-averaged properties of a well mixed or perfectly stirred reactor for plasma or thermal chemistry systems. The software was based on the previously released software, SURFACE PSR which was written for application to thermal CVD reactor systems. AURORA allows modeling of non-thermal, plasma reactors with the determination of ion and electron concentrations and the electron temperature, in addition to the neutral radical species concentrations. Well stirred reactors are characterized by a reactor volume, residence time or mass flow rate, heat loss or gas temperature, surface area, surface temperature, the incoming temperature and mixture composition, as well as the power deposited into the plasma for non-thermal systems. The model described here accounts for finite-rate elementary chemical reactions both in the gas phase and on the surface. The governing equations are a system of nonlinear algebraic relations. The program solves these equations using a hybrid Newton/time-integration method embodied by the software package TWOPNT. The program runs in conjunction with the new CHEMKIN-III and SURFACE CHEMKIN-III packages, which handle the chemical reaction mechanisms for thermal and non-thermal systems. CHEMKIN-III allows for specification of electron-impact reactions, excitation losses, and elastic-collision losses for electrons.

  1. In Situ SIMS and IR Spectroscopy of Well-Defined Surfaces Prepared by Soft Landing of Mass-Selected Ions

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Grant E.; Gunaratne, Kalupathirannehelage Don D.; Laskin, Julia

    2014-06-16

    Soft landing of mass-selected ions onto surfaces is a powerful approach for the highly-controlled preparation of materials that are inaccessible using conventional synthesis techniques. Coupling soft landing with in situ characterization using secondary ion mass spectrometry (SIMS) and infrared reflection absorption spectroscopy (IRRAS) enables analysis of well-defined surfaces under clean vacuum conditions. The capabilities of three soft-landing instruments constructed in our laboratory are illustrated for the representative system of surface-bound organometallics prepared by soft landing of mass-selected ruthenium tris(bipyridine) dications, [Ru(bpy)3]2+, onto carboxylic acid terminated self-assembled monolayer surfaces on gold (COOH-SAMs). In situ time-of-flight (TOF)-SIMS provides insight into the reactivity of the soft-landed ions. In addition, the kinetics of charge reduction, neutralization and desorption occurring on the COOH-SAM both during and after ion soft landing are studied using in situ Fourier transform ion cyclotron resonance (FT-ICR)-SIMS measurements. In situ IRRAS experiments provide insight into how the structure of organic ligands surrounding metal centers is perturbed through immobilization of organometallic ions on COOH-SAM surfaces by soft landing. Collectively, the three instruments provide complementary information about the chemical composition, reactivity and structure of well-defined species supported on surfaces.

  2. Attempts to grow optically coupled Fibonacci-spaced InGaAs/GaAs quantum wells result in surface gratings.

    Science.gov (United States)

    Richards, B C; Hendrickson, J; Sweet, J; Khitrova, G; Litvinov, D; Gerthsen, D; Myer, B; Pau, S; Sarid, D; Wegener, M; Ivchenko, E L; Poddubny, A N; Gibbs, H M

    2008-12-22

    An instability in the growth of nonperiodic InGaAs/GaAs multiple quantum well samples, ordinarily of high-quality when grown with equal periods of order of half the wavelength of light in the material, leads to a dramatic microscopic, self-organized surface grating. This effect was discovered while growing quantum wells with two unequal barrier lengths arranged in a Fibonacci sequence to form an optical quasicrystal. A laser beam incident normal to the surface of the sample is diffracted into a propeller-shaped pattern. The sample surface has a distinctly cloudy appearance when viewed along one crystal axis but is mirror-like when the sample is rotated 90 degrees. The instability results in a five-fold increase in the absorption linewidth of the heavy-hole exciton transition. Atomic force microscopy, transmission electron microscopy, and scanning electron microscopy were used to study the samples.

  3. Geomechanical modeling of surface uplift around well KB-502 at the in Salah CO2 storage site

    NARCIS (Netherlands)

    Fokker, P.A.; Orlic, B.; Meer, L.G.H. van der; Geel, C.R.

    2011-01-01

    Injection of CO2 in the InSalah field has caused uplift of the surface, as observed by satellite geodetic techniques (InSAR). Around one of the wells, KB-502, the uplift shows anomalous behaviour: a two-lobe pattern develops in the direction of the preferred fracture orientation. This indicates the

  4. Geomechanical modeling of surface uplift around well KB-502 at the in Salah CO2 storage site

    NARCIS (Netherlands)

    Fokker, P.A.; Orlic, B.; Meer, L.G.H. van der; Geel, C.R.

    2011-01-01

    Injection of CO2 in the InSalah field has caused uplift of the surface, as observed by satellite geodetic techniques (InSAR). Around one of the wells, KB-502, the uplift shows anomalous behaviour: a two-lobe pattern develops in the direction of the preferred fracture orientation. This indicates the

  5. GaAs/AlGaAs single quantum well p-i-n structures: A surface photovoltage study

    Science.gov (United States)

    Ashkenasy, N.; Leibovitch, M.; Rosenwaks, Y.; Shapira, Yoram; Barnham, K. W. J.; Nelson, J.; Barnes, J.

    1999-12-01

    The photovoltage (PV) response of single quantum well p-i-n structures under open circuit conditions has been studied experimentally and numerically. The numerical calculations show a monotonic increase in the PV response with decreasing well width, implying that the ensuing increase in carrier generation rate and band gap governs the PV response. The well layer has been shown to dominate the recombination of excess carriers generated throughout the structure, and their lifetime at the well has been found to be a critical structure parameter. Using a simple semi-empirical model, the effective carrier lifetimes at the well layer/interfaces for the different samples were estimated. The results demonstrate the benefits of using surface photovoltage spectroscopy for characterization and quality control of quantum well structures.

  6. Hole weak anti-localization in a strained-Ge surface quantum well

    Science.gov (United States)

    Mizokuchi, R.; Torresani, P.; Maurand, R.; Zeng, Z.; Niquet, Y.-M.; Myronov, M.; De Franceschi, S.

    2017-08-01

    We report a magneto-transport study of a two-dimensional hole gas confined to a strained Ge quantum well grown on a relaxed Si0.2Ge0.8 virtual substrate. The conductivity of the hole gas measured as a function of a perpendicular magnetic field exhibits a zero-field peak resulting from weak anti-localization. The peak develops and becomes stronger upon increasing the hole density by means of a top gate electrode. This behavior is consistent with a Rashba-type spin-orbit coupling whose strength is proportional to the perpendicular electric field and hence to the carrier density. In the low-density, the single-subband regime, by fitting the weak anti-localization peak to an analytic model, we extract the characteristic transport time scales and a spin splitting energy ΔSO˜ 1 meV. Tight-binding calculations show that ΔSO is dominated by a cubic term in the in-plane wave vector. Finally, we observe a weak anti-localization peak also for magnetic fields parallel to the quantum well and associate this finding to an effect of intersubband scattering induced by interface defects.

  7. Hydrogeochemical processes governing the origin, transport and fate of major and trace elements from mine wastes and mineralized rock to surface waters

    Science.gov (United States)

    Nordstrom, D. Kirk

    2011-01-01

    The formation of acid mine drainage from metals extraction or natural acid rock drainage and its mixing with surface waters is a complex process that depends on petrology and mineralogy, structural geology, geomorphology, surface-water hydrology, hydrogeology, climatology, microbiology, chemistry, and mining and mineral processing history. The concentrations of metals, metalloids, acidity, alkalinity, Cl-, F- and SO42- found in receiving streams, rivers, and lakes are affected by all of these factors and their interactions. Remediation of mine sites is an engineering concern but to design a remediation plan without understanding the hydrogeochemical processes of contaminant mobilization can lead to ineffective and excessively costly remediation. Furthermore, remediation needs a goal commensurate with natural background conditions rather than water-quality standards that might bear little relation to conditions of a highly mineralized terrain. This paper reviews hydrogeochemical generalizations, primarily from US Geological Survey research, that enhance our understanding of the origin, transport, and fate of contaminants released from mined and mineralized areas.

  8. Adsorption of biopolymers human serum albumin and human gamma globulin to well-defined surfaces of self-assembled monolayers

    Science.gov (United States)

    Cregger, Tricia Ann

    The tenacity with which the blood proteins Human Serum Albumin (HSA) and Human Gamma Globulin (HGG) adsorb to a surface modified with a monomolecular coating varies with the packing of the alkyl chains in the coating. The adsorption of proteins onto well-defined surfaces of self-assembled monolayers (SAMs) was studied with X-ray reflectometry (XR), neutron reflectometry (NR), optical reflectometry, and total internal reflection fluorescence (TIRF). NR and XR was used to study adsorption in the absence of flow, while optical reflectometry and TIRF were used to probe the adsorption under flow conditions. In particular, competitive adsorption measurements of binary solutions of HSA, HGG and Fibrinogen (FIB) were performed with TIRE The properties of the surface were varied by altering the alkyl chains' packing density and the chain end functionality of the SAMs. The depth profiles of protein concentration near the adsorbing surface measured by NR were dependent upon the chain packing density in the case of HSA. The concentration depth profile of HGG was unaltered by varying chain packing density. Measurements performed under flow using optical reflectometry showed a different behavior: the surface excess of adsorbed HSA was relatively independent of the surface packing, while the surface excess of HGG depended on the packing density of the SAM. The tenacity with which the proteins adsorbed to different functionalized surfaces was determined by attempting to remove the protein using a strong surfactant, sodium dodecyl sulfate (SDS). Ex situ XR measurements suggested that both HSA and HGG adsorb more tenaciously to a less densely-packed monolayer, almost independent of surface functionality. Two exceptions were a less densely-packed vinyl-terminated monolayer and a less densely-packed bromine-terminated monolayer, from which HSA could not be removed at all.

  9. Decoupling of surface and subsurface sutures in the Dabie orogen and a continent-collisional lithospheric-wedging model:Sr-Nd-Pb isotopic evidences of Mesozoic igneous rocks in eastern China

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    There are significant differences of Nd and Pb isotopic compositions between Mesozoic mafic igneous rocks from the North China Block (NCB) and the South China Block (SCB). Mesozoic mantle-derived igneous rocks from the North China Block have very low εNd values (-15 to -21), and 206Pb/204Pb ratios ( -10 and 206Pb/204Pb > 18.3. The very low εNd values (-16 to -20) and 206Pb/204Pb ratios (< 17.3) of the early Cretaceous mafic-ultramafic intrusions developed in the north part of the Dabie orogen (NDZ) suggest that the deep lithosphere underneath the NDZ belongs to the NCB but not the SCB. Therefore, although the surface suture between the NCB and SCB is located on the north side of the NDZ, the subsurface suture between the NCB and SCB should be located to the south side of the NDZ. This is consistent with the previous suggestion that the subsurface suture in the Sulu terrane east of the Tanlu fault was the south displacement, but contradictory to northward continental subduction of the SCB. A continent-collisional lithospheric- wedging model can interpret the decoupling of the surface and subsurface sutures in the Dabie-Sulu orogen. After slab break-off, the continuing convergence of two continental blocks must increase the compression force acting on the suture zone, which might induce the lithosphere splitting of SCB. Thus, the lower crust and lithospheric mantle on the south margin of the NCB can wedge into the north margin of the lithosphere of the SCB along the Dabie-Sulu collision zone. This process caused the overthrust of the mid-upper continental crust with exhumed ultrahigh pressure metamorphic (UHPM) rocks and underthrust of the deep lithosphere of the SCB. It could be an important mechanism responsible for the second rapid cooling and uplifting of the UHPM rocks and lithospheric delamination as well as the corresponding magmatism in Jurassic in the Dabie orogen. The southward movement of subsurface suture in the Dabie-Sulu orogen may also provide a

  10. From stones to rocks

    Science.gov (United States)

    Mortier, Marie-Astrid; Jean-Leroux, Kathleen; Cirio, Raymond

    2013-04-01

    With the Aquila earthquake in 2009, earthquake prediction is more and more necessary nowadays, and people are waiting for even more accurate data. Earthquake accuracy has increased in recent times mainly thanks to the understanding of how oceanic expansion works and significant development of numerical seismic prediction models. Despite the improvements, the location and the magnitude can't be as accurate as citizen and authorities would like. The basis of anticipating earthquakes requires the understanding of: - The composition of the earth, - The structure of the earth, - The relations and movements between the different parts of the surface of the earth. In order to answer these questions, the Alps are an interesting field for students. This study combines natural curiosity about understanding the predictable part of natural hazard in geology and scientific skills on site: observing and drawing landscape, choosing and reading a representative core drilling, replacing the facts chronologically and considering the age, the length of time and the strength needed. This experience requires students to have an approach of time and space radically different than the one they can consider in a classroom. It also limits their imagination, in a positive way, because they realize that prediction is based on real data and some of former theories have become present paradigms thanks to geologists. On each location the analyzed data include landscape, core drilling and the relation established between them by students. The data is used by the students to understand the meaning, so that the history of the formation of the rocks tells by the rocks can be explained. Until this year, the CBGA's perspective regarding the study of the Alps ground allowed students to build the story of the creation and disappearance of the ocean, which was a concept required by French educational authorities. But not long ago, the authorities changed their scientific expectations. To meet the

  11. Reactive-infiltration instabilities in rocks. Fracture dissolution

    CERN Document Server

    Szymczak, Piotr

    2012-01-01

    A reactive fluid dissolving the surface of a uniform fracture will trigger an instability in the dissolution front, leading to spontaneous formation of pronounced well-spaced channels in the surrounding rock matrix. Although the underlying mechanism is similar to the wormhole instability in porous rocks there are significant differences in the physics, due to the absence of a steadily propagating reaction front. In previous work we have described the geophysical implications of this instability in regard to the formation of long conduits in soluble rocks. Here we describe a more general linear stability analysis, including axial diffusion, transport limited dissolution, non-linear kinetics, and a finite length system.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-12-30

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

  13. System and method for investigating sub-surface features of a rock formation using compressional acoustic sources

    Science.gov (United States)

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

    2016-09-27

    A system and method for investigating rock formations outside a borehole are provided. The method includes generating a first compressional acoustic wave at a first frequency by a first acoustic source; and generating a second compressional acoustic wave at a second frequency by a second acoustic source. The first and the second acoustic sources are arranged within a localized area of the borehole. The first and the second acoustic waves intersect in an intersection volume outside the borehole. The method further includes receiving a third shear acoustic wave at a third frequency, the third shear acoustic wave returning to the borehole due to a non-linear mixing process in a non-linear mixing zone within the intersection volume at a receiver arranged in the borehole. The third frequency is equal to a difference between the first frequency and the second frequency.

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

    Science.gov (United States)

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

    2014-12-30

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

  15. Remedial Action Plan and Site Design for stabilization of the inactive Uranium Mill Tailings sites at Slick Rock, Colorado: Appendix C to Attachment 3, Calculations. Final

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-09-01

    This volume contains calculations for: Slick Rock processing sites background ground water quality; Slick Rock processing sites lysimeter water quality; Slick Rock processing sites on-site and downgradient ground water quality; Slick Rock disposal site background water quality; Burro Canyon disposal site, Slick Rock, Colorado, average hydraulic gradients and average liner ground water velocities in the upper, middle, and lower sandstone units of the Burro Canyon formation; Slick Rock--Burro Canyon disposal site, Burro Canyon pumping and slug tests--analyses; water balance and surface contours--Burro Canyon disposal cell; and analytical calculation of drawdown in a hypothetical well completed in the upper sandstone unit of the Burro Canyon formation.

  16. Pre- and post-stimulation characterization of geothermal well GRT-1, Rittershoffen, France: insights from acoustic image logs of hard fractured rock

    Science.gov (United States)

    Vidal, Jeanne; Genter, Albert; Schmittbuhl, Jean

    2016-08-01

    Geothermal well GRT-1 (Rittershoffen, Alsace) was drilled in 2012. Its open-hole section (extending down to a depth of 2.6 km) penetrated fractured sandstones and granite. In 2013, the well was subjected to Thermal, Chemical and Hydraulic (TCH) stimulation, which improved the injectivity index fivefold. The goal of the study was to assess the impact of the stimulation by comparing pre- and post-stimulation well-logging (acoustic and temperature [T] logs) and mud-logging data. This comparison revealed modifications of almost all the natural fractures. However, not all of these fractures are associated with permeability enhancement, and the post-stimulation T logs are important for characterizing this enhancement. Chemical alteration due to mechanical erosion at the tops and bottoms of the fractures was observed in the sandstones. These zones display indications of very small new permeability after the TCH stimulation. Because a major fault zone caved extensively where it crosses the borehole, it was not imaged in the acoustic logs. However, this originally permeable zone was enhanced as demonstrated by the T logs. Based on the natural injectivity of this fault zone, hydraulic erosion and thermal microcracking of its internal quartz veins are associated with this permeability enhancement. Although local changes in the borehole wall observed in the acoustic images cannot be directly linked to the improved injectivity index, the comparison of the acoustic image logs allows for identification of fracture zones impacted by the TCH stimulation.

  17. Surface photovoltage spectroscopy of an InGaAs/GaAs/AlGaAs single quantum well laser structure

    Science.gov (United States)

    Ashkenasy, N.; Leibovitch, M.; Shapira, Yoram; Pollak, Fred H.; Burnham, G. T.; Wang, X.

    1998-01-01

    An InGaAs/GaAs/AlGaAs single quantum well graded-index-of-refraction separate-confinement hetero-structure laser has been analyzed using surface photovoltage spectroscopy (SPS) in a contactless, nondestructive way at room temperature. Numerical simulation of the resulting spectrum made it possible to extract growth parameters, such as the InGaAs well width, the well and cladding compositions, as well as important electro-optic structure data of this device, including the lasing wavelength and built-in electric field. The results highlight the power of SPS in obtaining performance parameters of actual laser devices, containing two-dimensional structures, in a contactless, nondestructive way.

  18. Surface plasmon coupling dynamics in InGaN/GaN quantum-well structures and radiative efficiency improvement

    DEFF Research Database (Denmark)

    Fadil, Ahmed; Iida, Daisuke; Chen, Yuntian

    2014-01-01

    for InGaN/GaN quantum-well structures. By using a thin SiN dielectric layer between Ag and GaN we manage to modify and improve surface plasmon coupling effects, and we attribute this to the improved scattering of the nanoparticles at the quantum-well emission wavelength. The results are interpreted using...... numerical simulations, where absorption and scattering cross-sections are studied for different sized particles on GaN and GaN/SiN substrates....

  19. The "Pure Marriage" between 3D Printing and Well-Ordered Nanoarrays by Using PEALD Assisted Hydrothermal Surface Engineering.

    Science.gov (United States)

    Xue, Chaowen; Shi, Xiaotong; Fang, Xuan; Tao, Haiyan; Zhu, Hui; Yu, Fen; Ding, Xingwei; Liu, Miaoxing; Fang, Fang; Yang, Fan; Wei, Zhipeng; Chen, Tingtao; Wang, Zongliang; Wang, Guoping; Cheng, Xigao; Wei, Junchao; Lin, Yingjie; Deng, Keyu; Wang, Xiaolei; Xin, Hongbo

    2016-04-06

    For the first time, homogeneous and well-ordered functional nanoarrays were grown densely on the complex structured three-dimensional (3D) printing frameworks through a general plasma enhanced atomic layer deposition (PEALD) assisted hydrothermal surface engineering process. The entire process was free from toxic additives or harmful residues and, therefore, can meet the critical requirements of high-purity products. As a practical example, 3D customized earplugs were precisely manufactured according to the model of ear canals at the 0.1 mm level. Meanwhile, well-ordered ZnO nanoarrays, formed on the surfaces of these 3D printed earplugs, could effectively prevent the growth of five main pathogens derived from the patients with otitis media and exhibited excellent wear resistance as well. On the basis of both animal experiments and volunteers' investigations, the 3D customized earplugs showed sound insulation capabilities superior to those of traditional earplugs. Further animal experiments demonstrated the potential of as-modified implant scaffolds in practical clinical applications. This work, exemplified with earplugs and implant scaffolds, oriented the development direction of 3D printing in biomedical devices, which precisely integrated customized architecture and tailored surface performance.

  20. 57Fe Mössbauer spectroscopy study of organic rich sediments (source rocks) from test well CT-1, Chinnewala structure of Jaisalmer basin, India

    Institute of Scientific and Technical Information of China (English)

    R.P. Tripathi; Beena Bhatia; R. Sharma; K.R. Patel; S.S. Meena; Girish Ganwani; S.C. Mathur

    2016-01-01

    57Fe Mössbauer spectroscopic study was carried out on the organic rich sedimentary samples collected at different depth intervals from newly drilled test well Chinnewala Tibba-1 (CT-1) located in Jaisalmer Petroliferous basin India. It is found that iron is mainly distributed in high spin Fe3þ and Fe2þ state in clay minerals. The plot of Fe2þ/(Fe2þ þ Fe3þ) indicates the presence of poor redox conditions in the samples. Results obtained are also compared with those already reported in the literature. This comparison shows that there may exist a correlation between prospecting of the basin, the redox environment in sediments and the nature of iron bearing minerals distributed in the sedimentary sequence.

  1. ROCK ON

    National Research Council Canada - National Science Library

    Thomas Grose

    2014-01-01

    ..., however, was music - especially the high-pitched sounds of pop and rock, which boosted energy output by up to 40 percent. By contrast, classical music's lower pitches barely raised effectiveness. O...

  2. Weathering of rock 'Ginger'

    Science.gov (United States)

    1997-01-01

    One of the more unusual rocks at the site is Ginger, located southeast of the lander. Parts of it have the reddest color of any material in view, whereas its rounded lobes are gray and relatively unweathered. These color differences are brought out in the inset, enhanced at the upper right. In the false color image at the lower right, the shape of the visible-wavelength spectrum (related to the abundance of weathered ferric iron minerals) is indicated by the hue of the rocks. Blue indicates relatively unweathered rocks. Typical soils and drift, which are heavily weathered, are shown in green and flesh tones. The very red color in the creases in the rock surface correspond to a crust of ferric minerals. The origin of the rock is uncertain; the ferric crust may have grown underneath the rock, or it may cement pebbles together into a conglomerate. Ginger will be a target of future super-resolution studies to better constrain its origin.Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator. JPL is an operating division of the California Institute of Technology (Caltech).

  3. The world's deepest well

    Science.gov (United States)

    Kozlovskii, E. A.

    1984-12-01

    A 12,000-meter-deep research well at Kola in the Soviet Arctic is discussed. A major objective of the well was to penetrate into the basement rock of basaltic composition, presumably marked by an abrupt increase in the velocity of the seismic waves. At Kola the shift occurs at 9000 meters. However, instead of the basalt expected below that depth, an anomalous zone of disaggregated metamorphic rock was found. Further in that zone abundant flows of hot, highly mineralized 'water of crystallization' were found. Flows of gas, including helium, hydrogen, nitrogen, methane, and other hydrocarbons, and carbon dioxide were observed at all levels, thus indicating the existence of active gas-water processes, which raises the prospect of new ore deposits. The well utilizes a 400- to 500-ton aluminum alloy drill string. Unlike conventional drilling, the bit is powered by a turbine driven by the high-pressure flow of the drilling mud at 250 atm, which eliminates the disabling stresses at the surface caused by the rotation of the entire string. This technology opens the possibility of drilling to the depths of 15 to 17 km. The well is expected to help improve the interpretation of the seismic data.

  4. Controlled Growth of Well-Defined Conjugated Polymers from the Surfaces of Multiwalled Carbon Nanotubes: Photoresponse Enhancement via Charge Separation.

    Science.gov (United States)

    Hou, Wenpeng; Zhao, Ning-Jiu; Meng, Dongli; Tang, Jing; Zeng, Yi; Wu, Yu; Weng, Yangziwan; Cheng, Chungui; Xu, Xiulai; Li, Yi; Zhang, Jian-Ping; Huang, Yong; Bielawski, Christopher W; Geng, Jianxin

    2016-05-24

    The installation of heterojunctions on the surfaces of carbon nanotubes (CNTs) is an effective method for promoting the charge separation processes needed for CNT-based electronics and optoelectronics applications. Conjugated polymers are proven state-of-the-art candidates for modifying the surfaces of CNTs. However, all previous attempts to incorporate conjugated polymers to CNTs resulted in unordered interfaces. Herein we show that well-defined chains of regioregular poly(3-hexylthiophene) (P3HT) were successfully grown from the surfaces of multiwalled CNTs (MWNTs) using surface-initiated Kumada catalyst-transfer polycondensation. The polymerization was found to proceed in a controlled manner as chains of tunable lengths were prepared through variation of the initial monomer-to-initiator ratio. Moreover, it was determined that large-diameter MWNTs afforded highly ordered P3HT aggregates, which exhibited a markedly bathochromically shifted optical absorption due to a high grafting density induced planarization of the polymer chains. Using ultrafast spectroscopy, the heterojunctions formed between the MWNTs and P3HT were shown to effectively overcome the binding energy of excitons, leading to photoinduced electron transfer from P3HT to MWNTs. Finally, when used as prototype devices, the individual MWNT-g-P3HT core-shell structures exhibited excellent photoresponses under a low illumination density.

  5. Onset of surface stimulated emission at 260 nm from AlGaN multiple quantum wells

    KAUST Repository

    Li, Xiaohang

    2015-12-14

    We demonstrated onset of deep-ultraviolet (DUV) surface stimulated emission (SE) from c-plane AlGaNmultiple-quantum well(MQW)heterostructuresgrown on a sapphire substrate by optical pumping at room temperature. The onset of SE became observable at a pumping power density of 630 kW/cm2. Spectral deconvolution revealed superposition of a linearly amplified spontaneous emission peak at λ ∼ 257.0 nm with a full width at half maximum (FWHM) of ∼12 nm and a superlinearly amplified SE peak at λ ∼ 260 nm with a narrow FWHM of less than 2 nm. In particular, the wavelength of ∼260 nm is the shortest wavelength of surface SE from III-nitride MQWheterostructures to date. Atomic force microscopy and scanning transmission electron microscopy measurements were employed to investigate the material and structural quality of the AlGaNheterostructures, showing smooth surface and sharp layer interfaces. This study offers promising results for AlGaNheterostructuresgrown on sapphire substrates for the development of DUV vertical cavity surface emitting lasers(VCSELs).

  6. Surface Reaction Kinetics of Steam- and CO2-Reforming as Well as Oxidation of Methane over Nickel-Based Catalysts

    Directory of Open Access Journals (Sweden)

    Karla Herrera Delgado

    2015-05-01

    Full Text Available An experimental and kinetic modeling study on the Ni-catalyzed conversion of methane under oxidative and reforming conditions is presented. The numerical model is based on a surface reaction mechanism consisting of 52 elementary-step like reactions with 14 surface and six gas-phase species. Reactions for the conversion of methane with oxygen, steam, and CO2 as well as methanation, water-gas shift reaction and carbon formation via Boudouard reaction are included. The mechanism is implemented in a one-dimensional flow field description of a fixed bed reactor. The model is evaluated by comparison of numerical simulations with data derived from isothermal experiments in a flow reactor over a powdered nickel-based catalyst using varying inlet gas compositions and operating temperatures. Furthermore, the influence of hydrogen and water as co-feed on methane dry reforming with CO2 is also investigated.

  7. Well-Defined Molybdenum Oxo Alkyl Complex Supported on Silica by Surface Organometallic Chemistry: A Highly Active Olefin Metathesis Precatalyst.

    Science.gov (United States)

    Merle, Nicolas; Le Quéméner, Frédéric; Bouhoute, Yassine; Szeto, Kai C; De Mallmann, Aimery; Barman, Samir; Samantaray, Manoja K; Delevoye, Laurent; Gauvin, Régis M; Taoufik, Mostafa; Basset, Jean-Marie

    2017-02-15

    The well-defined silica-supported molybdenum oxo alkyl species (≡SiO-)MoO(CH2(t)Bu)3 was selectively prepared by grafting of MoO(CH2(t)Bu)3Cl onto partially dehydroxylated silica (silica700) using the surface organometallic chemistry approach. This surface species was fully characterized by elemental analysis and DRIFT, solid-state NMR, and EXAFS spectroscopy. This new material is related to the active species of industrial supported MoO3/SiO2 olefin metathesis catalysts. It displays very high activity in propene self-metathesis at mild (turnover number = 90 000 after 25 h). Remarkably, its catalytic performance outpaces those of the parent imido derivative and its tungsten oxo analogue.

  8. Computer program for predicting surface subsidence resulting from pressure depletion in geopressured wells: subsidence prediction for the DOW test well No. 1, Parcperdue, Louisiana

    Energy Technology Data Exchange (ETDEWEB)

    Janssen, J.C.; Carver, D.R.; Bebout, D.G.; Bachman, A.L. (eds.)

    1981-01-01

    The nucleus-of-strain concept is used to construct a computer program for predicting surface subsidence due to pressure reduction in geopressured reservoirs. Numerical integration allows one to compute the vertical displacement of the ground surface directly above and beyond the aquifer boundaries which results from the pressure reduction in each of the small finite volumes into which the aquifer is partitioned. The program treats depth (measured from the surface to the mean thickness of the aquifer) as a constant. Variation in aquifer thickness is accounted for by linear interpolation from one boundary to its opposite. In this simple model, subsidence is proportional to the pressure reduction (considered constant in this presentation) and to but one physical parameter, Cm(1-..nu..), in which Cm is its coefficient of uniaxial compaction, and ..nu.. is Poisson's ratio.

  9. Critical issues in soft rocks

    Institute of Scientific and Technical Information of China (English)

    Milton Assis Kanji

    2014-01-01

    This paper discusses several efforts made to study and investigate soft rocks, as well as their physico-mechanical characteristics recognized up to now, the problems in their sampling and testing, and the possibility of its reproduction through artificially made soft rocks. The problems in utilizing current and widespread classification systems to some types of weak rocks are also discussed, as well as other problems related to them. Some examples of engineering works in soft rock or in soft ground are added, with emphasis on their types of problems and solutions.

  10. Research on surface mortar of ETICS based on rock wool%防水型岩棉外保温系统抹面砂浆研究

    Institute of Scientific and Technical Information of China (English)

    王辉; 王霞

    2011-01-01

    针对岩棉对水敏感的弱点,重点研究具有良好防水功能的岩棉外保温系统抹面砂浆,对比了EVA乳胶粉和丙烯酸乳胶粉与有机硅憎水剂在抹面砂浆中复合使用情况,研究结果表明,丙烯酸乳胶粉的防水性更为优异,丙烯酸乳胶粉7042W掺量2.5%时可以使5mm抹面砂浆不透水,EVA乳胶粉6022E和有机硅憎水剂复合使用也可以达到相同效果;在热老化作用下,抹面砂浆的吸水量有所增加,抗冲击强度有所下降,丙烯酸乳胶粉7042W的耐热老化性能明显优于EVA乳胶粉6022E.%Aiming at the water-sensitive weakness of rock wool, surface mortar for rock wool-based ETICS with good waterproof performance was particularly researched. The compound use condition of EVA emulsion powder, acrylic latex powder with silicone water repellent in surface mortar was compared. The research results showed that the waterproof performance of acrylic latex powder was better, 5 mm surface mortar can be impermeable when the content of acrylic latex powder 7042W was 2.5%. And compound use of EVA emulsion powder 6022E and silicone water repellent can achieve the same effect; under the function of thermal aging, the water absorption of the surface mortar increased, and impact strength decreased. Hie heat-resisting performance of acrylic latex powder 7042W was significantly better than that of EVA emulsion powder 6022E.

  11. Synthesis of High Surface Area and Well Crystallized Mesoporous WC at Low Temperature with a Pore Structure Collapsed Replication Route

    Institute of Scientific and Technical Information of China (English)

    LI Hua; SHI Jianlin; CHEN Hangrong; ZHANG Lingxia; LI Lei

    2011-01-01

    An approach named "pore structure collapsed replication route" has been developed to prepare mesoporous WC materials with a high surface area (105 m2/g) and crystallized framework at a temperature as low as 700 ℃. The XRD, TEM, EDS, and BET characterizations were conducted to analyze the effects of the synthesis parameters and the template types on the structure of mesoporous WC. The compaction on the templates is the key to form mesoporous structure of WC while the templates help to control the size of crystalline. At a content of 7 wt% for the precursor of WC, the mesoporous WC could be formed with well ordered structure.

  12. High-sensitivity time-resolved intracavity laser Fourier transform spectroscopy with vertical cavity surface emitting multiple quantum well lasers

    CERN Document Server

    Picqué, N; Kachanov, A A; Picqu\\'e, Nathalie; Guelachvili, Guy; Kachanov, Alexander A.

    2003-01-01

    Spectra comprised of hundreds of time-components for absorption path lengths up to 130 km have been recorded around 1050 nm by combining two recent techniques, intracavity laser spectroscopy with vertical external cavity surface emitting multiple-quantum-well lasers and time-resolved Fourier transform spectroscopy. A sensitivity of 1 10^{-10} cm^{-1}.Hz^{-1/2} is achieved, for simultaneously acquired 10^4 spectral elements, three orders of magnitude better than the sensitivity obtained in previous similar experiments. Specific advantages of the method, especially for frequency and intensity metrology of weak absorption transitions, are discussed.

  13. Active microwave remote sensing research program plan. Recommendations of the Earth Resources Synthetic Aperture Radar Task Force. [application areas: vegetation canopies, surface water, surface morphology, rocks and soils, and man-made structures

    Science.gov (United States)

    1980-01-01

    A research program plan developed by the Office of Space and Terrestrial Applications to provide guidelines for a concentrated effort to improve the understanding of the measurement capabilities of active microwave imaging sensors, and to define the role of such sensors in future Earth observations programs is outlined. The focus of the planned activities is on renewable and non-renewable resources. Five general application areas are addressed: (1) vegetation canopies, (2) surface water, (3) surface morphology, (4) rocks and soils, and (5) man-made structures. Research tasks are described which, when accomplished, will clearly establish the measurement capabilities in each area, and provide the theoretical and empirical results needed to specify and justify satellite systems using imaging radar sensors for global observations.

  14. Effect of the surface roughness on the seismic signal generated by a single rock impact: insight from laboratory experiments

    Science.gov (United States)

    Bachelet, Vincent; Mangeney, Anne; de Rosny, Julien; Toussaint, Renaud

    2016-04-01

    The seismic signal generated by rockfalls, landslides or avalanches is a unique tool to detect, characterize and monitor gravitational flow activity, with strong implication in terms of natural hazard monitoring. Indeed, as natural flows travel down the slope, they apply stresses on the ground, generating seismic waves in a wide frequency band. Our ultimate objective is to relate the granular flow properties to the generated signals that result from the different physical processes involved. We investigate here the more simple process: the impact of a single bead on a rough surface. Farin et al. [2015] have already shown theoretically and experimentally the existence of a link between the properties of an impacting bead (mass and velocity) on smooth surfaces, and the emitted signal (radiated elastic energy and mean frequency). This demonstrates that the single impactor properties can be deduced from the form of the emitted signal. We extend this work here by investigating the impact of single beads and gravels on rough and erodible surfaces. Experimentally, we drop glass and steel beads of diameters from 2 mm to 10 mm on a PMMA plate. The roughness of this last is obtained by gluing 3mm-diameter glass beads on one of its face. Free beads have been also added to get erodible beds. We track the dropped impactor motion, times between impacts and the generated acoustic waves using two fast cameras and 8 accelerometers. Cameras are used in addition to estimate the impactor rotation. We investigate the energy balance during the impact process, especially how the energy restitution varies as a function of the energy lost through acoustic waves. From these experiments, we clearly observe that even if more dissipative processes are involved (friction, grain reorganization, etc.), the single bead scaling laws obtained on smooth surfaces remain valid. A main result of this work is to quantify the fluctuations of the characteristic quantities such as the bounce angle, the

  15. 'Wopmay' Rock

    Science.gov (United States)

    2004-01-01

    This approximate true-color image taken by NASA's Mars Exploration Rover Opportunity shows an unusual, lumpy rock informally named 'Wopmay' on the lower slopes of 'Endurance Crater.' The rock was named after the Canadian bush pilot Wilfrid Reid 'Wop' May. Like 'Escher' and other rocks dotting the bottom of Endurance, scientists believe the lumps in Wopmay may be related to cracking and alteration processes, possibly caused by exposure to water. The area between intersecting sets of cracks eroded in a way that created the lumpy appearance. Rover team members plan to drive Opportunity over to Wopmay for a closer look in coming sols. This image was taken by the rover's panoramic camera on sol 248 (Oct. 4, 2004), using its 750-, 530- and 480-nanometer filters.

  16. Geochemical characterization of surface water and spring water in SE Kashmir Valley, western Himalaya: Implications to water–rock interaction

    Indian Academy of Sciences (India)

    Gh Jeelani; Nadeem A Bhat; K Shivanna; M Y Bhat

    2011-10-01

    Water samples from precipitation, glacier melt, snow melt, glacial lake, streams and karst springs were collected across SE of Kashmir Valley, to understand the hydrogeochemical processes governing the evolution of the water in a natural and non-industrial area of western Himalayas. The time series data on solute chemistry suggest that the hydrochemical processes controlling the chemistry of spring waters is more complex than the surface water. This is attributed to more time available for infiltrating water to interact with the diverse host lithology. Total dissolved solids (TDS), in general, increases with decrease in altitude. However, high TDS of some streams at higher altitudes and low TDS of some springs at lower altitudes indicated contribution of high TDS waters from glacial lakes and low TDS waters from streams, respectively. The results show that some karst springs are recharged by surface water; Achabalnag by the Bringi stream and Andernag and Martandnag by the Liddar stream. Calcite dissolution, dedolomitization and silicate weathering were found to be the main processes controlling the chemistry of the spring waters and calcite dissolution as the dominant process in controlling the chemistry of the surface waters. The spring waters were undersaturated with respect to calcite and dolomite in most of the seasons except in November, which is attributed to the replenishment of the CO2 by recharging waters during most of the seasons.

  17. Well-defined nanostructured surface-imprinted polymers for highly selective magnetic separation of fluoroquinolones in human urine.

    Science.gov (United States)

    He, Yonghuan; Huang, Yanyan; Jin, Yulong; Liu, Xiangjun; Liu, Guoquan; Zhao, Rui

    2014-06-25

    The construction of molecularly imprinted polymers on magnetic nanoparticles gives access to smart materials with dual functions of target recognition and magnetic separation. In this study, the superparamagnetic surface-molecularly imprinted nanoparticles were prepared via surface-initiated reversible addition-fragmentation chain transfer (RAFT) polymerization using ofloxacin (OFX) as template for the separation of fluoroquinolones (FQs). Benefiting from the living/controlled nature of RAFT reaction, distinct core-shell structure was successfully constructed. The highly uniform nanoscale MIP layer was homogeneously grafted on the surface of RAFT agent TTCA modified Fe3O4@SiO2 nanoparticles, which favors the fast mass transfer and rapid binding kinetics. The target binding assays demonstrate the desirable adsorption capacity and imprinting efficiency of Fe3O4@MIP. High selectivity of Fe3O4@MIP toward FQs (ofloxacin, pefloxacin, enrofloxacin, norfloxacin, and gatifloxacin) was exhibited by competitive binding assay. The Fe3O4@MIP nanoparticles were successfully applied for the direct enrichment of five FQs from human urine. The spiked human urine samples were determined and the recoveries ranging from 83.1 to 103.1% were obtained with RSD of 0.8-8.2% (n = 3). This work provides a versatile approach for the fabrication of well-defined MIP on nanomaterials for the analysis of complicated biosystems.

  18. Swift heavy ion irradiated InGaAs/InP multi quantum wells: Band-structure, interface and surface modifications

    Energy Technology Data Exchange (ETDEWEB)

    Dhamodaran, S. [School of Physics, University of Hyderabad, Central University (P.O.), Hyderabad 500 046 (India); Pathak, A.P. [School of Physics, University of Hyderabad, Central University (P.O.), Hyderabad 500 046 (India)], E-mail: appsp@uohyd.ernet.in; Turos, A. [Institute of Electronic Materials Technology, 01-919 Warsaw, ul. Wolczynska 133 (Poland); Soltan Institute of Nuclear Studies, 05-400 Swierk/Otwock (Poland); Saravanan, G Sai [Gallium Arsenide Enabling Technology Centre, Vignyanakancha (P.O.), Hyderabad 500 069 (India); Khan, S.A.; Avasthi, D.K. [Inter University Accelerator Centre, P. O. Box 10502, Aruna Asaf Ali Marg, New Delhi 110 067 (India); Arora, B.M. [Tata Institute of Fundamental Research, Homibhabha Road, Colaba, Mumbai 400 005 (India)

    2008-02-15

    The band-structure, interface and surface modification by swift heavy ion irradiation of In{sub 0.55}Ga{sub 0.45}As/InP multi quantum wells have been studied using photoluminescence, high resolution X-ray diffraction and atomic force microscopy. Three distinct photoluminescence peaks were observed for as-grown samples at low temperature and at room temperature the peaks merge together. Detailed analysis has been carried out to understand the origin of additional satellite peaks. A peak shift of about 23 nm was observed for irradiated samples after annealing. Highly-ordered satellite peaks were observed in X-ray scans of as-grown and Ag ion irradiated samples. In comparison, Au ion irradiated sample showed stronger interfacial degradation as seen by the diminished satellite peaks. The peak position of the irradiated samples shifted to the compressive side and was broadened in comparison with as-grown samples. The as-grown and annealed samples show smooth surfaces whereas irradiation results in nano-sized dot/island types of structures at the surface. The results are discussed in the light of complementary information provided by these techniques.

  19. Deep surface grating DFB and DBR quantum well diode lasers in AlGaAs/GaAs for photonic integration

    Science.gov (United States)

    Ayling, Stephen G.; Moreira, M. V.; Abe, H.; Bryce, A. Catrina; De La Rue, Richard M.; Marsh, John H.

    1995-03-01

    Deep surface grating structures make possible the fabrication of DFB and DBR structures where the usual epitaxial regrowth processes which compromise device yield and reliability are avoided. A key requirement is that the gratings are etched to a well-controlled depth position close to the waveguide core. This paper describes the fabrication processes for the grating/stripe waveguide structures in both DFB lasers with gratings exterior to a central stripe (effectively providing refractive index confinement) and DBR lasers with gratings etched into the central ridge region. Issues of etch depth precision, grating pattern definition using either electron beam lithography or holography and measurement of the grating coupling coefficient, K, are addressed. Both pulsed and CW measurements of DFB laser performance have been carried out including lasers with a novel (lambda) /4 shift. In the DBR lasers, quantum well intermixing via impurity free vacancy disordering has been used to reduce the optical absorption in the unpumped region below the reflector grating. A direction extension of this intermixing approach will allow the development of a more general waveguide-based integration technology in which DFB and DBR lasers are combined with passive waveguide sections and other discrete devices to form a complete photonic chip. The prospects for successful implementation of this integration discussed and an example given using a surface grating DFB laser.

  20. A Study of the Connection Among Basin-Fill Aquifers, Carbonate-Rock Aquifers, and Surface-Water Resources in Southern Snake Valley, Nevada

    Science.gov (United States)

    ,

    2008-01-01

    The Secretary of the Interior through the Southern Nevada Public Lands Management Act approved funding for research to improve understanding of hydrologic systems that sustain numerous water-dependent ecosystems on Federal lands in Snake Valley, Nevada. Some of the streams and spring-discharge areas in and adjacent to Great Basin National Park have been identified as susceptible to ground-water withdrawals (Elliott and others, 2006) and research has shown a high potential for ground-water flow from southern Spring Valley into southern Snake Valley through carbonate rocks that outcrop along a low topographic divide known as the Limestone Hills (Welch and others, 2007). Comprehensive geologic, hydrologic, and chemical information will be collected and analyzed to assess the hydraulic connection between basin-fill aquifers and surface-water resources, water-dependent ecological features, and the regional carbonate-rock aquifer, the known source of many high-discharge springs. Understanding these connections is important because proposed projects to pump and export ground water from Spring and Snake Valleys in Nevada may result in unintended capture of water currently supplying springs, streams, wetlands, limestone caves, and other biologically sensitive areas (fig. 1). The methods that will be used in this study may be transferable to other areas in the Great Basin. The National Park Service, Bureau of Land Management, U.S. Fish and Wildlife Service, and U.S. Forest Service submitted the proposal for funding this research to facilitate science-based land management. Scientists from the U.S. Geological Survey (USGS) Water Resources and Geologic Disciplines, and the University of Nevada, Reno, will accomplish four research elements through comprehensive data collection and analysis that are concentrated in two distinct areas on the eastern and southern flanks of the Snake Range (fig. 2). The projected time line for this research is from July 2008 through September 2011.

  1. 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

  2. 堡古1井花岗岩地层钻头优选与应用%Bit selection and application for granite rock of Well Pugu-1

    Institute of Scientific and Technical Information of China (English)

    李贵宾; 刘泳敬; 柳耀泉; 黄建

    2011-01-01

    Well Pugu-1 in Jidong Oilfield is an exploration well with CNPC rank risk at high position of Nanpu No. 4 buried hill block. The drilling of the well is to wildcat the oil and gas saturation status of Archaean granite buried hill reservoirs. Granite rocks are buried deep, with high strength and poor ability of drilling, so the drilling operations in adjacent area come across the problems of short bit footage, short longevity, and low penetration rate. Based on the analysis on the granite formation properties, temperature, drillability, and the bit application on the adjacent wells, it was studied that the bit sealing type, cogging structure, protection on wheel and wheel carrier, and service life. And the monometallic sealing meteacarpal aggrandizement bit for slim hole was designed with long service life and high penetration rate. The technique made a new path for quickly penetrating granite rock in the area.%冀东油田堡古1井是部署在南堡4号潜山北断块较高部位的一口中石油重点风险探井,主要钻探目的是预探太古界花岗岩潜山含油气情况.花岗岩地层埋藏深、强度高、可钻性差,邻区实钻存在单只钻头进尺少、寿命短、机械钻速低的问题.在分析深部花岗岩地层物性、温度、可钻性和邻井钻头应用的基础上,对钻头密封类型、切削齿结构、牙掌及牙轮保护、使用寿命等方面进行了研究,设计出了适用于小井眼的单金属密封掌背强化牙轮钻头,现场使用不仅寿命长,而且获得了较高的机械钻速,为该区花岗岩地层快速钻进提供了技术支撑.

  3. Method of treating wells

    Energy Technology Data Exchange (ETDEWEB)

    Knox, J.A.; Lasater, R.M.

    1966-11-22

    Chemical compositions and methods are provided for treating underground formations to render their surfaces water-repellent or preferentially oil-wettable. Previous methods have provided only temporary water-repellency because they do not actually act chemically with the reservoir rock. This improvement is obtained by using a treating agent which does not form a precipitate upon hydrolysis with water, such as a liquid organo-halogen- silane or its ester. A water-soluble anhydrous solvent which is nonreactive with the silane is used as a carrier. This method may be used for treating non-oil-bearing aquifers for increasing the flow rate of water, such as in water supply wells, or in water input rate, such as in water disposal wells. (10 claims)

  4. Reconstruction of basal heat flow, surface temperature, source rock maturity, and hydrocarbon generation in salt-dominated dutch basins

    NARCIS (Netherlands)

    Verweij, H.M.; Echternach, M.S.C.; Witmans, N.; Abdul Fattah, R.

    2012-01-01

    A rapidly growing demand for improved understanding of the Dutch subsurface exists because of the need for alternative energy supplies, such as geothermal energy, as well as for finding and producing more oil and gas in this mature area for petroleum exploration. We use basin modeling to integrate t

  5. Coherent oscillations of holes in GaAs0.86P0.14/Al0.7Ga0.3As surface quantum well

    Indian Academy of Sciences (India)

    Salahuddin Khan; J Jayabalan; Asha Singh; Rama Chari; Suparna Pal; S Porwal; T K Sharma; S M Oak

    2014-02-01

    We show that in a GaAs0.86P0.14/Al0.7Ga0.3As near-surface quantum well, there is coherent oscillation of holes observed in time-resolved reflectivity signal when the top barrier of the quantum well is sufficiently thin. The quantum well states interact with the surface states under the influence of the surface electric field. The time period of the observed oscillation is 120±10 fs.

  6. 30 CFR 57.3203 - Rock fixtures.

    Science.gov (United States)

    2010-07-01

    ... HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Ground Control Scaling and Support-Surface and Underground § 57.3203 Rock fixtures. (a) For rock bolts and accessories addressed in... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Rock fixtures. 57.3203 Section 57.3203 Mineral...

  7. Rock Paintings.

    Science.gov (United States)

    Jones, Julienne Edwards

    1998-01-01

    Discusses the integration of art and academics in a fifth-grade instructional unit on Native American culture. Describes how students studied Native American pictographs, designed their own pictographs, made their own tools, and created rock paintings of their pictographs using these tools. Provides a list of references on Native American…

  8. Ayers Rock

    Institute of Scientific and Technical Information of China (English)

    王慧茹

    2002-01-01

    Ayers Rock is right in the centre of Australia.It's nearly two thousand kilometres______Sydney.So we flew most of the way.h was rather cloudy______But after we left the mountains behind us, there was hardly a cloud in thesky.

  9. Intellektuaalne rock

    Index Scriptorium Estoniae

    2007-01-01

    Briti laulja-helilooja ja näitleja Toyah Willcox ning Bill Rieflin ansamblist R.E.M. ja Pat Mastelotto King Krimsonist esinevad koos ansamblitega The Humans ja Tuner 25. okt. Tallinnas Rock Cafés ja 27. okt Tartu Jaani kirikus

  10. Intellektuaalne rock

    Index Scriptorium Estoniae

    2007-01-01

    Briti laulja-helilooja ja näitleja Toyah Willcox ning Bill Rieflin ansamblist R.E.M. ja Pat Mastelotto King Krimsonist esinevad koos ansamblitega The Humans ja Tuner 25. okt. Tallinnas Rock Cafés ja 27. okt Tartu Jaani kirikus

  11. Study on the deterioration mechanism of layered rock-salt electrodes using epitaxial thin films - Li(Ni, Co, Mn)O2 and their Zr-O surface modified electrodes

    Science.gov (United States)

    Abe, Machiko; Iba, Hideaki; Suzuki, Kota; Minamishima, Hiroaki; Hirayama, Masaaki; Tamura, Kazuhisa; Mizuki, Jun'ichiro; Saito, Tomohiro; Ikuhara, Yuichi; Kanno, Ryoji

    2017-03-01

    Deterioration mechanism of Li(Ni, Co, Mn)O2 and Zr-O surface modified electrodes has been elucidated using epitaxial thin films synthesized by pulsed laser deposition. The electrodes comprise a mixture of layered rock-salt and spinel phases. The deterioration mechanism is analyzed using cyclic voltammetry, in situ X-ray diffraction measurements, and in situ neutron reflectometry. The spinel phase in the electrodes has low electrochemical activity and is not involved in Li insertion/extraction. The amount of Li participating in the charge-discharge reactions in the layered rock-salt phase increases with cycling, inducing a phase change at the electrode surface, lowering the reversibility. In contrast, in the Zr-O surface modified electrode, the spinel phase does not increase on charging/discharging. Thus, the Zr-O modification stabilizes the surface of layered rock-salt structure, thereby improving the cycling characteristics. Also, after the Zr-O modification, the Li concentration in the liquid electrolyte near the electrode/electrolyte interface increases during charging/discharging. The Zr-O surface modification not only stabilizes the electrode surface but also causes changes on the electrolyte side. Using the mixed model electrodes, we elucidate the mechanism of electrode deterioration and the origin of the improvement in cycling characteristics occurring on surface modification.

  12. Tensile rock mass strength estimated using InSAR

    KAUST Repository

    Jonsson, Sigurjon

    2012-11-01

    The large-scale strength of rock is known to be lower than the strength determined from small-scale samples in the laboratory. However, it is not well known how strength scales with sample size. I estimate kilometer-scale tensional rock mass strength by measuring offsets across new tensional fractures (joints), formed above a shallow magmatic dike intrusion in western Arabia in 2009. I use satellite radar observations to derive 3D ground displacements and by quantifying the extension accommodated by the joints and the maximum extension that did not result in a fracture, I put bounds on the joint initiation threshold of the surface rocks. The results indicate that the kilometer-scale tensile strength of the granitic rock mass is 1–3 MPa, almost an order of magnitude lower than typical laboratory values.

  13. Simultaneous coupling of surface plasmon resonance and photonic bandgap to InGaAs quantum well emission

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Hongwei [Engineering Product Development, Singapore University of Technology and Design, Singapore 487372 (Singapore); Teng, Jinghua [Institute of Materials Research and Engineering, Singapore 117602 (Singapore); Chua, Soo Jin, E-mail: elecsj@nus.edu.sg [Institute of Materials Research and Engineering, Singapore 117602 (Singapore); Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576 (Singapore)

    2016-01-07

    A photonic bandgap structure was created on the 100 nm thick GaAs barrier layer with Au nanodisks deposited inside the holes. To mitigate the nonradiative surface recombination of GaAs, the Au nanodisks were formed on top of a 15 nm SiO{sub 2} deposited in the holes. A maximum 7.6-fold increase in photoluminescence intensity was obtained at the etch depth of 80 nm. In this configuration, the Au nanodisk is separated from the quantum well by 20 nm of GaAs and 15 nm of SiO{sub 2}. The experimental result was verified by the simulation based on this structure. There was a good agreement between experiments with simulation results.

  14. System and method for generating 3D images of non-linear properties of rock formation using surface seismic or surface to borehole seismic or both

    Science.gov (United States)

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

    2016-06-07

    A system and method of characterizing properties of a medium from a non-linear interaction are include generating, by first and second acoustic sources disposed on a surface of the medium on a first line, first and second acoustic waves. The first and second acoustic sources are controllable such that trajectories of the first and second acoustic waves intersect in a mixing zone within the medium. The method further includes receiving, by a receiver positioned in a plane containing the first and second acoustic sources, a third acoustic wave generated by a non-linear mixing process from the first and second acoustic waves in the mixing zone; and creating a first two-dimensional image of non-linear properties or a first ratio of compressional velocity and shear velocity, or both, of the medium in a first plane generally perpendicular to the surface and containing the first line, based on the received third acoustic wave.

  15. 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.

  16. Numerical simulation study on hard-thick roof inducing rock burst in coal mine

    Institute of Scientific and Technical Information of China (English)

    何江; 窦林名; 牟宗龙; 曹安业; 巩思园

    2016-01-01

    In order to reveal the dynamic process of hard-thick roof inducing rock burst, one of the most common and strongest dynamic disasters in coal mine, the numerical simulation is conducted to study the dynamic loading effect of roof vibration on roadway surrounding rocks as well as the impact on stability. The results show that, on one hand, hard-thick roof will result in high stress concentration on mining surrounding rocks; on the other hand, the breaking of hard-thick roof will lead to mining seismicity, causing dynamic loading effect on coal and rock mass. High stress concentration and dynamic loading combination reaches to the mechanical conditions for the occurrence of rock burst, which will induce rock burst. The mining induced seismic events occurring in the roof breaking act on the mining surrounding rocks in the form of stress wave. The stress wave then has a reflection on the free surface of roadway and the tensile stress will be generated around the free surface. Horizontal vibration of roadway surrounding particles will cause instant changes of horizontal stress of roadway surrounding rocks; the horizontal displacement is directly related to the horizontal stress but is not significantly correlated with the vertical stress; the increase of horizontal stress of roadway near surface surrounding rocks and the release of elastic deformation energy of deep surrounding coal and rock mass are immanent causes that lead to the impact instability of roadway surrounding rocks. The most significant measures for rock burst prevention are controlling of horizontal stress and vibration strength.

  17. Robotic Ankle for Omnidirectional Rock Anchors

    Science.gov (United States)

    Parness, Aaron; Frost, Matthew; Thatte, Nitish

    2013-01-01

    Future robotic exploration of near-Earth asteroids and the vertical and inverted rock walls of lava caves and cliff faces on Mars and other planetary bodies would require a method of gripping their rocky surfaces to allow mobility without gravitational assistance. In order to successfully navigate this terrain and drill for samples, the grippers must be able to produce anchoring forces in excess of 100 N. Additionally, the grippers must be able to support the inertial forces of a moving robot, as well gravitational forces for demonstrations on Earth. One possible solution would be to use microspine arrays to anchor to rock surfaces and provide the necessary load-bearing abilities for robotic exploration of asteroids. Microspine arrays comprise dozens of small steel hooks supported on individual suspensions. When these arrays are dragged along a rock surface, the steel hooks engage with asperities and holes on the surface. The suspensions allow for individual hooks to engage with asperities while the remaining hooks continue to drag along the surface. This ensures that the maximum possible number of hooks engage with the surface, thereby increasing the load-bearing abilities of the gripper. Using the microspine array grippers described above as the end-effectors of a robot would allow it to traverse terrain previously unreachable by traditional wheeled robots. Furthermore, microspine-gripping robots that can perch on cliffs or rocky walls could enable a new class of persistent surveillance devices for military applications. In order to interface these microspine grippers with a legged robot, an ankle is needed that can robotically actuate the gripper, as well as allow it to conform to the large-scale irregularities in the rock. The anchor serves three main purposes: deploy and release the anchor, conform to roughness or misalignment with the surface, and cancel out any moments about the anchor that could cause unintentional detachment. The ankle design contains a

  18. Rock size-frequency distributions analysis at lunar landing sites based on remote sensing and in-situ imagery

    Science.gov (United States)

    Li, Bo; Ling, Zongcheng; Zhang, Jiang; Chen, Jian

    2017-10-01

    Rock populations can supply fundamental geological information about origin and evolution of a planet. In this paper, we used Lunar Reconnaissance Orbiter (LRO) narrow-angle camera (NAC) images to identify rocks at the lunar landing sites (including Chang'e 3 (CE-3), Apollo and Surveyor series). The diameter and area of each identified rock were measured to generate distributions of rock cumulative fractional area and size-frequency on a log-log plot. The two distributions both represented the same shallow slopes at smaller diameters followed by steeper slopes at larger diameters. A reasonable explanation for the lower slopes may be the resolution and space weathering effects. By excluding the smaller diameters, rock populations derived from NAC images showed approximately linear relationships and could be fitted well by power laws. In the last, the entire rock populations derived from both NAC and in-situ imagery could be described by one power function at the lunar landing sites except the CE-3 and Apollo 11 landing sites. This may be because that the process of a large rock breaking down to small rocks even fine particles can be modeled by fractal theories. Thus, rock populations on lunar surfaces can be extrapolated along the curves of rock populations derived from NAC images to smaller diameters. In the future, we can apply rock populations from remote sensing images to estimate the number of rocks with smaller diameters to select the appropriate landing sites for the CE-4 and CE-5 missions.

  19. 基于BP神经网络的测井资料预测岩石热导率%Prediction of Thermal Conductivity of Rocks Through Geophysical Well Logs Based on BP Neural Network

    Institute of Scientific and Technical Information of China (English)

    蒋海燕; 施小斌; 杨小秋; 石红才

    2012-01-01

    In order to obtain thermal conductivity of rocks at the depth where no core is available, we build ua prediction model for thermal conductivity based on BP neural networks with sonic, density, neutron porosity, resistivity, gamma ray as input. The prediction model needs short estimating time without any more lithological composition data, therefore it has more and wider applications than the empirical formula only influenced by one or several physical parameters. The test results from the test samples and 1144A, 1146A, 1148A well logs show that the error given by our model is less than the maximum permissible error of thermal conductivity measurement under laboratory conditions. This model provides a new way for obtaining thermal conductivity of rocks at the depth where has no core but has the related geophysical well logs.%为了获取无岩心深度段的岩石热导率,建立基于BP神经网络的热导率预测模型.根据声波、密度、中子、电阻率、自然伽马等5种测井响应预测岩石热导率,其模型计算所需时间较短,不需要岩性组分资料,比只考虑1种或其中几种物理参数影响的经验公式适用范围更广.对检验样本以及位于南海的1144A井、1146A井、1148A井等3口大洋科学钻探ODP(Ocean Drilling Program)钻孔的热导率预测结果表明,模型预测的热导率误差低于实验室岩石热导率测试的最大允许误差.该热导率预测模型为获取没有岩心的上述5种测井响应的深度段的岩石热导率提供了一种新途径.

  20. Investigation of surface-plasmon coupled red light emitting InGaN/GaN multi-quantum well with Ag nanostructures coated on GaN surface

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yi; Liu, Bin, E-mail: bliu@nju.edu.cn, E-mail: rzhang@nju.edu.cn; Zhang, Rong, E-mail: bliu@nju.edu.cn, E-mail: rzhang@nju.edu.cn; Xie, Zili; Zhuang, Zhe; Dai, JiangPing; Tao, Tao; Zhi, Ting; Zhang, Guogang; Chen, Peng; Ren, Fangfang; Zhao, Hong; Zheng, Youdou [Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, People' s Republic of China and Nanjing National Laboratory of Microstructures, Nanjing University, Nanjing 210093 (China)

    2015-04-21

    Surface-plasmon (SP) coupled red light emitting InGaN/GaN multiple quantum well (MQW) structure is fabricated and investigated. The centre wavelength of 5-period InGaN/GaN MQW structure is about 620 nm. The intensity of photoluminescence (PL) for InGaN QW with naked Ag nano-structures (NS) is only slightly increased due to the oxidation of Ag NS as compared to that for the InGaN QW. However, InGaN QW with Ag NS/SiO{sub 2} structure can evidently enhance the emission efficiency due to the elimination of surface oxide layer of Ag NS. With increasing the laser excitation power, the PL intensity is enhanced by 25%–53% as compared to that for the SiO{sub 2} coating InGaN QW. The steady-state electric field distribution obtained by the three-dimensional finite-difference time-domain method is different for both structures. The proportion of the field distributed in the Ag NS for the GaN/Ag NS/SiO{sub 2} structure is smaller as compared to that for the GaN/naked Ag NS structure. As a result, the energy loss of localized SP modes for the GaN/naked Ag NS structure will be larger due to the absorption of Ag layer.

  1. Hot Dry Rock; Geothermal Energy

    Energy Technology Data Exchange (ETDEWEB)

    None

    1990-01-01

    The commercial utilization of geothermal energy forms the basis of the largest renewable energy industry in the world. More than 5000 Mw of electrical power are currently in production from approximately 210 plants and 10 000 Mw thermal are used in direct use processes. The majority of these systems are located in the well defined geothermal generally associated with crustal plate boundaries or hot spots. The essential requirements of high subsurface temperature with huge volumes of exploitable fluids, coupled to environmental and market factors, limit the choice of suitable sites significantly. The Hot Dry Rock (HDR) concept at any depth originally offered a dream of unlimited expansion for the geothermal industry by relaxing the location constraints by drilling deep enough to reach adequate temperatures. Now, after 20 years intensive work by international teams and expenditures of more than $250 million, it is vital to review the position of HDR in relation to the established geothermal industry. The HDR resource is merely a body of rock at elevated temperatures with insufficient fluids in place to enable the heat to be extracted without the need for injection wells. All of the major field experiments in HDR have shown that the natural fracture systems form the heat transfer surfaces and that it is these fractures that must be for geothermal systems producing from naturally fractured formations provide a basis for directing the forthcoming but, equally, they require accepting significant location constraints on HDR for the time being. This paper presents a model HDR system designed for commercial operations in the UK and uses production data from hydrothermal systems in Japan and the USA to demonstrate the reservoir performance requirements for viable operations. It is shown that these characteristics are not likely to be achieved in host rocks without stimulation processes. However, the long term goal of artificial geothermal systems developed by systematic

  2. Stabilization of rock salt ZnO nanocrystals by low-energy surfaces and Mg additions : A first-principles study

    NARCIS (Netherlands)

    Koster, Rik S.; Fang, Changming M.; Dijkstra, Marjolein; Van Blaaderen, Alfons; Van Huis, Marijn A.

    2015-01-01

    Whereas bulk zinc oxide (ZnO) exhibits the wurtzite crystal structure, nanoscale ZnO was recently synthesized in the rock salt structure by addition of Mg. Using first-principles methods, we investigated two stabilization routes for accessing rock salt ZnO. The first route is stabilization by Mg add

  3. A Val85Met mutation in melanocortin-1 receptor is associated with reductions in eumelanic pigmentation and cell surface expression in domestic rock pigeons (Columba livia.

    Directory of Open Access Journals (Sweden)

    Michael W Guernsey

    Full Text Available Variation in the melanocortin-1 receptor (Mc1r is associated with pigmentation diversity in wild and domesticated populations of vertebrates, including several species of birds. Among domestic bird species, pigmentation variation in the rock pigeon (Columbalivia is particularly diverse. To determine the potential contribution of Mc1r variants to pigment diversity in pigeons, we sequenced Mc1r in a wide range of pigeon breeds and identified several single nucleotide polymorphisms, including a variant that codes for an amino acid substitution (Val85Met. In contrast to the association between Val85Met and eumelanism in other avian species, this change was associated with pheomelanism in pigeons. In vitro cAMP accumulation and protein expression assays revealed that Val85Met leads to decreased receptor function and reduced cell surface expression of the mutant protein. The reduced in vitro function is consistent with the observed association with reduced eumelanic pigmentation. Comparative genetic and cellular studies provide important insights about the range of mechanisms underlying diversity among vertebrates, including different phenotypic associations with similar mutations in different species.

  4. Differentiation and analysis on rock breaking characteristics of TBM disc cutter at different rock temperatures

    Institute of Scientific and Technical Information of China (English)

    谭青; 张桂菊; 夏毅敏; 李建芳

    2015-01-01

    In order to study rock breaking characteristics of tunnel boring machine (TBM) disc cutter at different rock temperatures, thermodynamic rock breaking mathematical model of TBM disc cutter was established on the basis of rock temperature change by using particle flow code theory and the influence law of interaction mechanism between disc cutter and rock was also numerically simulated. Furthermore, by using the linear cutting experiment platform, rock breaking process of TBM disc cutter at different rock temperatures was well verified by the experiments. Finally, rock breaking characteristics of TBM disc cutter were differentiated and analyzed from microscale perspective. The results indicate the follows. 1) When rock temperature increases, the mechanical properties of rock such as hardness, and strength, were greatly reduced, simultaneously the microcracks rapidly grow with the cracks number increasing, which leads to rock breaking load decreasing and improves rock breaking efficiency for TBM disc cutter. 2) The higher the rock temperature, the lower the rock internal stress. The stress distribution rules coincide with the Buzin Neske stress circle rules: the maximum stress value is below the cutting edge region and then gradually decreases radiant around; stress distribution is symmetrical and the total stress of rock becomes smaller. 3) The higher the rock temperature is, the more the numbers of micro, tensile and shear cracks produced are by rock as well as the easier the rock intrusion, along with shear failure mode mainly showing. 4) With rock temperature increasing, the resistance intrusive coefficients of rock and intrusion power decrease obviously, so the specific energy consumption that TBM disc cutter achieves leaping broken also decreases subsequently. 5) The acoustic emission frequency remarkably increases along with the temperature increasing, which improves the rock breaking efficiency.

  5. Vulnerability of shallow ground water and drinking-water wells to nitrate in the United States: Model of predicted nitrate concentration in shallow, recently recharged ground water -- Input data set for carbonate rocks (gwava-s_crox)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set represents the presence or absence of Valley and Ridge carbonate rocks in the conterminous United States. The data set was used as an input data layer...

  6. Vulnerability of shallow ground water and drinking-water wells to nitrate in the United States: Model of predicted nitrate concentration in shallow, recently recharged ground water -- Input data set for basalt and volcanic rocks (gwava-s_vrox)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set represents the presence or absence of basalt and volcanic rocks in the conterminous United States. The data set was used as an input data layer for a...

  7. Geology and ground-water resources of Rock County, Wisconsin

    Science.gov (United States)

    LeRoux, E.F.

    1964-01-01

    Rock County is in south-central Wisconsin adjacent to the Illinois State line. The county has an area of about 723 square miles and had a population of about 113,000 in 1957 ; it is one of the leading agricultural and industrial counties in the State. The total annual precipitation averages about 32 inches, and the mean annual temperature is about 48 ? F. Land-surface altitudes are generally between 800 and 00 feet, but range from 731 feet, where the Rock River flows into Illinois, to above 1,080 feet, at several places in the northwestern part of the county. The northern part of Rock County consists of the hills and kettles of a terminal moraine which slopes southward to a flat, undissected outwash plain. The southeastern part of the county is an area of gentle slopes, whereas the southwestern part consists of steep-sided valleys and ridges. Rock County is within the drainage basin of the Rock River, which flows southward through the center of the county. The western and southwestern parts of ,the county are drained by the Sugar River und Coon Creek, both of which flow into the Pecatonica River in Illinois and thence into the Rock River. The southeastern part of the county is drained by Turtle Creek, which also flows into Illinois before joining the Rock River. Nearly all the lakes and ponds are in the northern one-third of the county, the area of most recent glaciation. The aquifers in Rock County are of sedimentary origin and include deeply buried sandstones, shales, and dolomites of the Upper Cambrian series. This series overlies crystalline rocks of Precambrian age and supplies water to all the cities and villages in the county. The St. Peter sandstone of Ordovician age underlies all Rock County except where the formation has been removed by erosion in the Rock and Sugar River valleys, and perhaps in Coon Creek valley. The St. Peter sandstone is the principal source of water for domestic, stock, and small industrial wells in the western half of the county

  8. Rock mass response to strong ground motion generated by mining induced seismic events and blasting observed at the surface of the excavations in deep level gold mines in South Africa

    Science.gov (United States)

    Milev, Alexander; Durrheim, Ray; Ogasawara, Hiroshi

    2014-05-01

    The strong ground motion generated by mining induced seismic events was studied to characterize the rock mass response and to estimate the site effect on the surface of the underground excavations. A stand-alone instruments, especially designed for recording strong ground motions, were installed underground at a number of deep level gold mines in South Africa. The instruments were recording data at the surface of the stope hangingwalls. A maximum value of 3 m/s was measured. Therefore data were compared to the data recorded in the solid rock by the mine seismic networks to determine the site response. The site response was defined as the ratio of the peak ground velocity measured at the surface of the excavations to the peak ground velocity inferred from the mine seismic data measured in the solid rocks. The site response measured at all mines studied was found to be 9 ± 3 times larger on average. A number of simulated rockbursts were conducted underground in order to estimate the rock mass response when subjected to extreme ground motion and derive the attenuation factors in near field. The rockbursts were simulated by means of large blasts detonated in solid rock close to the sidewall of a tunnel. The numerical models used in the design of the simulated rockbursts were calibrated by small blasts taking place at each experimental site. A dense array of shock type accelerometers was installed along the blasting wall to monitor the attenuation of the strong ground motion as a function of the distance from the source. The attenuation of the ground motion was found to be proportional to the distance from the source following R^-1.1 & R^-1.7 for compact rock and R^-3.1 & R^-3.4 for more fractured rock close to the surface of the tunnel. In addition the ground motion was compared to the quasi-static deformations taking place around the underground excavations. The quasi-static deformations were measured by means of strain, tilt and closure. A good correspondence

  9. Digital carbonate rock physics

    Science.gov (United States)

    Saenger, Erik H.; Vialle, Stephanie; Lebedev, Maxim; Uribe, David; Osorno, Maria; Duda, Mandy; Steeb, Holger

    2016-08-01

    Modern estimation of rock properties combines imaging with advanced numerical simulations, an approach known as digital rock physics (DRP). In this paper we suggest a specific segmentation procedure of X-ray micro-computed tomography data with two different resolutions in the µm range for two sets of carbonate rock samples. These carbonates were already characterized in detail in a previous laboratory study which we complement with nanoindentation experiments (for local elastic properties). In a first step a non-local mean filter is applied to the raw image data. We then apply different thresholds to identify pores and solid phases. Because of a non-neglectable amount of unresolved microporosity (micritic phase) we also define intermediate threshold values for distinct phases. Based on this segmentation we determine porosity-dependent values for effective P- and S-wave velocities as well as for the intrinsic permeability. For effective velocities we confirm an observed two-phase trend reported in another study using a different carbonate data set. As an upscaling approach we use this two-phase trend as an effective medium approach to estimate the porosity-dependent elastic properties of the micritic phase for the low-resolution images. The porosity measured in the laboratory is then used to predict the effective rock properties from the observed trends for a comparison with experimental data. The two-phase trend can be regarded as an upper bound for elastic properties; the use of the two-phase trend for low-resolution images led to a good estimate for a lower bound of effective elastic properties. Anisotropy is observed for some of the considered subvolumes, but seems to be insignificant for the analysed rocks at the DRP scale. Because of the complexity of carbonates we suggest using DRP as a complementary tool for rock characterization in addition to classical experimental methods.

  10. Revegetation/rock cover for stabilization of inactive uranium mill tailings disposal sites

    Energy Technology Data Exchange (ETDEWEB)

    Beedlow, P.A.; McShane, M.C.; Cadwell, L.L.

    1982-07-01

    Pacific Northwest Laboratory is developing design and performance guidelines for surface stabilization of inactive uranium mill tailings. In this work, vegetation and rock covers are being evaluated for maintaining long-term integrity of impoundment systems. Methods are being developed to estimate erosion rates associated with rock and/or vegetation covers, and to determine the effects of surface treatments on soil moisture. Interactions between surface treatments and barriers (radon and biological) are being studied as well. The product will be a set of guidelines to aid in designing surface covers. This report presents the status of this program and a discussion of considerations pertinent to the application of surface covers to tailings. Test plots located in Grand Junction, Colorado and Waterflow, New Mexico are being used to study: (1) the interactions between vegetation and radon and biological barriers, (2) the effects of surface covers on soil moisture, and (3) the effects of rock covers on vegetation.

  11. Engineering rock mass classification of the Olkiluoto investigation site

    Energy Technology Data Exchange (ETDEWEB)

    Aeikaes, K. [ed.; Hagros, A.; Johansson, E. [Saanio and Riekkola Consulting Engineers, Helsinki (Finland)] [and others

    2000-06-01

    Olkiluoto in Eurajoki is being investigated as a possible site for the final disposal of spent nuclear fuel from the Finnish nuclear power plants. The selection of the depth, placement and layout of the repository is affected by the constructability of the bedrock. The constructability, in turn, is influenced by several properties of the host rock, such as its Ethology, the extent of fracturing, its hydrogeological properties and rock engineering characteristics and also by the magnitude and orientation of the in situ stresses and the chemistry of the groundwater. The constructability can be evaluated by the application of a rock classification system in which the properties of the host rock are assessed against common rock engineering judgements associated with underground construction. These judgements are based partly on measurements of in situ stresses and the properties of the bedrock determined from rock samples, but an important aspect is also the practical experience which has been gained during underground excavation in similar conditions and rock types. The aim of the engineering rock mass classification was to determine suitable bedrock volumes for the construction of the repository and has used data from the site characterisation programme carried out at Olkiluoto, which consisted of both surface studies and borehole investigations. The classification specifies three categories of constructability - normal, demanding and very demanding. In addition, rock mass quality has also been classified according to the empirical Q-system to enable a comparison to be made. The rock mass parameters that determine the constructability of the bedrock at Olkiluoto depend primarily on the depth and the Ethology, as well as on whether construction takes place in intact or in fractured rock. The differences in the characteristics of intact rock within a single rock type have been shown to be small. The major lithological unit at Olkiluoto, the mica gneiss, lies in the

  12. How well do we characterize the biophysical effects of vegetation cover change? Benchmarking land surface models against satellite observations.

    Science.gov (United States)

    Duveiller, Gregory; Forzieri, Giovanni; Robertson, Eddy; Georgievski, Goran; Li, Wei; Lawrence, Peter; Ciais, Philippe; Pongratz, Julia; Sitch, Stephen; Wiltshire, Andy; Arneth, Almut; Cescatti, Alessandro

    2017-04-01

    Changes in vegetation cover can affect the climate by altering the carbon, water and energy cycles. The main tools to characterize such land-climate interactions for both the past and future are land surface models (LSMs) that can be embedded in larger Earth System models (ESMs). While such models have long been used to characterize the biogeochemical effects of vegetation cover change, their capacity to model biophysical effects accurately across the globe remains unclear due to the complexity of the phenomena. The result of competing biophysical processes on the surface energy balance varies spatially and seasonally, and can lead to warming or cooling depending on the specific vegetation change and on the background climate (e.g. presence of snow or soil moisture). Here we present a global scale benchmarking exercise of four of the most commonly used LSMs (JULES, ORCHIDEE, JSBACH and CLM) against a dedicated dataset of satellite observations. To facilitate the understanding of the causes that lead to discrepancies between simulated and observed data, we focus on pure transitions amongst major plant functional types (PFTs): from different tree types (evergreen broadleaf trees, deciduous broadleaf trees and needleleaf trees) to either grasslands or crops. From the modelling perspective, this entails generating a separate simulation for each PFT in which all 1° by 1° grid cells are uniformly covered with that PFT, and then analysing the differences amongst them in terms of resulting biophysical variables (e.g net radiation, latent and sensible heat). From the satellite perspective, the effect of pure transitions is obtained by unmixing the signal of different 0.05° spatial resolution MODIS products (albedo, latent heat, upwelling longwave radiation) over a local moving window using PFT maps derived from the ESA Climate Change Initiative land cover map. After aggregating to a common spatial support, the observation and model-driven datasets are confronted and

  13. Rock.XML - Towards a library of rock physics models

    Science.gov (United States)

    Jensen, Erling Hugo; Hauge, Ragnar; Ulvmoen, Marit; Johansen, Tor Arne; Drottning, Åsmund

    2016-08-01

    Rock physics modelling provides tools for correlating physical properties of rocks and their constituents to the geophysical observations we measure on a larger scale. Many different theoretical and empirical models exist, to cover the range of different types of rocks. However, upon reviewing these, we see that they are all built around a few main concepts. Based on this observation, we propose a format for digitally storing the specifications for rock physics models which we have named Rock.XML. It does not only contain data about the various constituents, but also the theories and how they are used to combine these building blocks to make a representative model for a particular rock. The format is based on the Extensible Markup Language XML, making it flexible enough to handle complex models as well as scalable towards extending it with new theories and models. This technology has great advantages as far as documenting and exchanging models in an unambiguous way between people and between software. Rock.XML can become a platform for creating a library of rock physics models; making them more accessible to everyone.

  14. A well-defined mesoporous amine silica surface via a selective treatment of SBA-15 with ammonia

    KAUST Repository

    Bendjeriou-Sedjerari, Anissa

    2012-01-01

    2D double-quantum 1H- 1H NMR unambiguously shows that the "isolated" Si-OH surface silanols of dehydroxylated SBA-15 are converted upon treatment with ammonia into single silylamine surface site Si-NH 2. The "gem" di-silanols (Si(OH) 2) remain intact. Treatment using HMDS produces (Si(OSiMe 3) 2) but leaves Si-NH 2 untouched. The resulting surface is hydrophobic and stable. © The Royal Society of Chemistry 2012.

  15. PETROCHEMISTRY AND MINERALOGY EVIDENCES FOR THE WEATHERING PROCESS OF THE WEATHERING PITS ON ROCK SURFACES OF MOUNTAIN LAOSHAN,CHINA%崂山山顶风化坑化学风化过程的岩石化学与矿物学证据

    Institute of Scientific and Technical Information of China (English)

    王为; 周尚哲; 李炳元; 林志海; 刘志鹏; 黄日辉; 赖宜讯; 陈科景

    2012-01-01

    ) The elements, Ca and Mg poor in the original rock, are rich in the detritus of the weathering pits. They are not the elements produced by rock weathering, but from external sources such as atmospheric deposition which is very popular in the areas around Mountain Laoshan; 4) Both the pits and the rock surfaces are affected by weathering action because both have CIA values lower than those of the original rock; 5) The values of CIA of the detritus in the weathering pits cannot be an indicator for the local climate environment and CIA value increases with time for weathering processes, which make the difference between the values of the pits on the mountain top and those of deposits at foot of the mountain; 6) The fact that LOI can reflect the different weathering intensity very well between the pits and rock surface indicates that the feldspar weathering in the pits is formed by the hydration and also that the origin of weathering pit comes from water collection in early depress on rock surface.%2011年5月对崂山山顶风化坑进行考察和采样,通过对风化坑内碎屑和坑外岩石的粉晶X射线衍射矿物分析、X射线荧光光谱化学全量分析,研究了风化坑内外的矿物风化及各元素迁移特征,对风化坑的成因过程进行探讨.研究结果表明:1)崂山山顶风化坑碎屑的英长比总是大于其周边岩石的英长比,说明风化坑的形成是花岗岩造岩矿物差异风化的结果;2)风化坑风化过程中被风化的岩石矿物主要是条纹长石和钾长石;3)风化坑中大量的Mg和Ca主要是外部加入的;4)崂山山顶风化坑内碎屑,坑外岩石面均受到化学风化的作用;5)崂山山顶风化坑内外的风化指数CIA值并不反映崂山当地的气候,山上山下CIA值的差异是风化时间长短不同造成的;6)LOI能很好地反映崂山风化坑内外风化强度的差异,说明长石主要在水解作用下发生分解,也说明了风化坑的积水成因.

  16. Strontium and neodymium isotope systematics of target rocks and impactites from the El'gygytgyn impact structure: Linking impactites and target rocks

    Science.gov (United States)

    Wegner, Wencke; Koeberl, Christian

    2016-12-01

    The 3.6 Ma El'gygytgyn structure, located in northeastern Russia on the Chukotka Peninsula, is an 18 km diameter complex impact structure. The bedrock is formed by mostly high-silica volcanic rocks of the 87 Ma old Okhotsk-Chukotka Volcanic Belt (OCVB). Volcanic target rocks and impact glasses collected on the surface, as well as drill core samples of bedrock and impact breccias have been investigated by thermal ionization mass spectrometry (TIMS) to obtain new insights into the relationships between these lithologies in terms of Nd and Sr isotope systematics. Major and trace element data for impact glasses are added to compare with the composition of target rocks and drill core samples. Sr isotope data are useful tracers of alteration processes and Nd isotopes reveal characteristics of the magmatic sources of the target rocks, impact breccias, and impact glasses. There are three types of target rocks mapped on the surface: mafic volcanics, dacitic tuff and lava of the Koekvun' Formation, and dacitic to rhyolitic ignimbrite of the Pykarvaam Formation. The latter represents the main contributor to the impact rocks. The drill core is divided into a suevite and a bedrock section by the Sr isotope data, for which different postimpact alteration regimes have been detected. Impact glasses from the present-day surface did not suffer postimpact hydrothermal alteration and their data indicate a coherent alteration trend in terms of Sr isotopes with the target rocks from the surface. Surprisingly, the target rocks do not show isotopic coherence with the Central Chukotka segment of the OCVB or with the Berlozhya magmatic assemblage (BMA), a late Jurassic felsic volcanic suite that crops out in the eastern part of the central Chukotka segment of the OCVB. However, concordance for these rocks exists with the Okhotsk segment of the OCVB. This finding argues for variable source magmas having contributed to the build-up of the OCVB.

  17. Assessment of the contamination of drinking water supply wells by pesticides from surface water resources using a finite element reactive transport model and global sensitivity analysis techniques

    DEFF Research Database (Denmark)

    Malaguerra, Flavio; Albrechtsen, Hans-Jørgen; Binning, Philip John

    2013-01-01

    fluorescein dye injected in a river is monitored at nearby drinking water wells. Three compounds were considered: an older pesticide MCPP (Mecoprop) which is mobile and relatively persistent, glyphosate (Roundup), a newer biodegradable and strongly sorbing pesticide, and its degradation product AMPA. Global...... contamination from surface water. This study suggests that it is unlikely that glyphosate in streams can pose a threat to drinking water wells, while MCPP in surface water can represent a risk: MCPP concentration at the drinking water well can be up to 7% of surface water concentration in confined aquifers...... and up to 10% in unconfined aquifers. Thus, the presence of confining clay aquitards may not prevent contamination of drinking water wells by persistent compounds in surface water. Results are consistent with data on pesticide occurrence in Denmark where pesticides are found at higher concentrations...

  18. Field Observation of Joint Structures in Various Types of Igneous Rocks

    Science.gov (United States)

    Kano, Shingo; Tsuchiya, Noriyoshi

    2006-05-01

    In this study, field observations of natural fracture network systems in some intrusive and extrusive rocks were undertaken, to clarify the fracturing mechanism in the rocks. Shallow intrusives, whose depth of emplacement was less than several hundred metres, include the Momo-iwa Dacite dome on Rebun Island (Hokkaido), and Jodogahama Rhyolite in Iwate prefecture. Extrusive complexes studied include the Tojinbo Andesite and Ojima Rhyodacite in Fukui prefecture. Rocks of `granitic' composition were collected from the Takidani (Japan Alps) and Hijiori (Yamagata prefecture) plutons. The joint structure in Hijiori Granite was evaluated by analysis of core samples extracted from the HDR-3 geothermal production well. Based on detailed field observation, joint structures related to thermal contraction of a rock mass could be classified according to their inferred depth of formation. Joints from a near surface setting, such as shallow intrusive rocks and extrusives, tend to form pentagonal — hexagonal columnar structures (for a variety of rock types), whilst granitic rocks (from a deeper setting) typically exhibit a parallelepiped structure. The apparent differences in joint form are inferred to be dependent on the confining pressure, which acts on joint generation and propagation. In cases of non-confining pressure, such as the near-surface (shallow intrusive/extrusive) setting, joint networks typically form a columnar structure. On the contrary, confining pressure is considerably greater for deeper rock masses, and these form a parallelepiped joint structure.

  19. Laboratory experiments for defining scaling relations between rock material properties and rock resistance to erosion

    Science.gov (United States)

    Sklar, L. S.; Beyeler, J. D.; Collins, G. C.; Farrow, J. W.; Hsu, L.; Litwin, K. L.; Polito, P. J.

    2012-12-01

    Rock resistance to erosion is a key variable that limits rates of morphologic change and mass flux in landscapes. However, we have limited knowledge of how measurable material properties influence rock resistance to specific erosion processes. Rock 'erodibility' is commonly a free parameter in surface process models, where users assign or solve for numerical values that lack meaning outside of the model. Moreover, erodibility parameters often lump material resistance to erosion together with aspects of the forces driving erosion that are not explicitly represented in the model. Laboratory experiments in which rock types are varied, while erosive forces are held constant, can be used to develop scaling relationships between rock properties and erosion resistance for individual detachment mechanisms. With knowledge of why erosion rates vary between rock types for constant erosive forces, laboratory and field experiments that vary erosive intensity can be used to quantify the absolute susceptibility to erosion in physically explicit terms. Here we synthesize data collected over the past decade from a suite of laboratory investigations of rock resistance to wear by sediment particle impacts, and wear of sediment particles themselves, in experiments replicating fluvial and granular flow conditions. Materials tested included: field-sampled bedrock and sediment covering the widest feasible range of apparent durability and lithologic type; synthetic sandstones made from mixtures of sand and Portland cement; and water ice, both pure and containing solid impurities, tested over a wide range of temperatures. Material properties measured included: dry-bulk and saturated density, porosity, tensile strength, fracture toughness, elastic moduli, mineralogy, cement type, and the grain size of mineral crystals and cemented clasts. Erosion rates were measured by mass or volume loss divided by run time, in bedrock abrasion mills, barrel tumblers, and a large rotating drum. We find

  20. Source rock potential in Pakistan

    Energy Technology Data Exchange (ETDEWEB)

    Raza, H.A. (Hydrocarbon Development Institute of Pakistan, Islamabad (Pakistan))

    1991-03-01

    Pakistan contains two sedimentary basins: Indus in the east and Balochistan in the west. The Indus basin has received sediments from precambrian until Recent, albeit with breaks. It has been producing hydrocarbons since 1914 from three main producing regions, namely, the Potwar, Sulaisman, and Kirthar. In the Potwar, oil has been discovered in Cambrian, Permian, Jurassic, and Tertiary rocks. Potential source rocks are identified in Infra-Cambrian, Permian, Paleocene, and Eocene successions, but Paleocene/Eocene Patala Formation seems to be the main source of most of the oil. In the Sulaiman, gas has been found in Cretaceous and Tertiary; condensate in Cretaceous rocks. Potential source rocks are indicated in Cretaceous, Paleocene, and Eocene successions. The Sembar Formation of Early Cretaceous age appears to be the source of gas. In the Kirthar, oil and gas have been discovered in Cretaceous and gas has been discovered in paleocene and Eocene rocks. Potential source rocks are identified in Kirthar and Ghazij formations of Eocene age in the western part. However, in the easter oil- and gas-producing Badin platform area, Union Texas has recognized the Sembar Formation of Early Cretaceous age as the only source of Cretaceous oil and gas. The Balochistan basin is part of an Early Tertiary arc-trench system. The basin is inadequately explored, and there is no oil or gas discovery so far. However, potential source rocks have been identified in Eocene, Oligocene, Miocene, and Pliocene successions based on geochemical analysis of surface samples. Mud volcanoes are present.

  1. Radiometry rocks

    Science.gov (United States)

    Harvey, James E.

    2012-10-01

    Professor Bill Wolfe was an exceptional mentor for his graduate students, and he made a major contribution to the field of optical engineering by teaching the (largely ignored) principles of radiometry for over forty years. This paper describes an extension of Bill's work on surface scatter behavior and the application of the BRDF to practical optical engineering problems. Most currently-available image analysis codes require the BRDF data as input in order to calculate the image degradation from residual optical fabrication errors. This BRDF data is difficult to measure and rarely available for short EUV wavelengths of interest. Due to a smooth-surface approximation, the classical Rayleigh-Rice surface scatter theory cannot be used to calculate BRDFs from surface metrology data for even slightly rough surfaces. The classical Beckmann-Kirchhoff theory has a paraxial limitation and only provides a closed-form solution for Gaussian surfaces. Recognizing that surface scatter is a diffraction process, and by utilizing sound radiometric principles, we first developed a linear systems theory of non-paraxial scalar diffraction in which diffracted radiance is shift-invariant in direction cosine space. Since random rough surfaces are merely a superposition of sinusoidal phase gratings, it was a straightforward extension of this non-paraxial scalar diffraction theory to develop a unified surface scatter theory that is valid for moderately rough surfaces at arbitrary incident and scattered angles. Finally, the above two steps are combined to yield a linear systems approach to modeling image quality for systems suffering from a variety of image degradation mechanisms. A comparison of image quality predictions with experimental results taken from on-orbit Solar X-ray Imager (SXI) data is presented.

  2. Assessment of the contamination of drinking water supply wells by pesticides from surface water resources using a finite element reactive transport model and global sensitivity analysis techniques

    Science.gov (United States)

    Malaguerra, Flavio; Albrechtsen, Hans-Jørgen; Binning, Philip John

    2013-01-01

    SummaryA reactive transport model is employed to evaluate the potential for contamination of drinking water wells by surface water pollution. The model considers various geologic settings, includes sorption and degradation processes and is tested by comparison with data from a tracer experiment where fluorescein dye injected in a river is monitored at nearby drinking water wells. Three compounds were considered: an older pesticide MCPP (Mecoprop) which is mobile and relatively persistent, glyphosate (Roundup), a newer biodegradable and strongly sorbing pesticide, and its degradation product AMPA. Global sensitivity analysis using the Morris method is employed to identify the dominant model parameters. Results show that the characteristics of clay aquitards (degree of fracturing and thickness), pollutant properties and well depths are crucial factors when evaluating the risk of drinking water well contamination from surface water. This study suggests that it is unlikely that glyphosate in streams can pose a threat to drinking water wells, while MCPP in surface water can represent a risk: MCPP concentration at the drinking water well can be up to 7% of surface water concentration in confined aquifers and up to 10% in unconfined aquifers. Thus, the presence of confining clay aquitards may not prevent contamination of drinking water wells by persistent compounds in surface water. Results are consistent with data on pesticide occurrence in Denmark where pesticides are found at higher concentrations at shallow depths and close to streams.

  3. Seismic properties of polyphase rocks

    Science.gov (United States)

    Wang, Qin

    2005-11-01

    Knowledge about the seismic properties of polyphase rocks is fundamental for interpreting seismic refraction and reflection data and for establishing lithospheric structure and composition models. This study aims to obtain more precise relationships between seismic properties of rocks and controlling factors (e.g., pressure, temperature, mineralogical and chemical compositions, microstructure of rocks), particularly for those rocks imprinted by ultrahigh-pressure (UHP) metamorphism. These relationships will be very helpful to extrapolate calculated and measured seismic properties of rocks to depths of interest and to engender interpretations relevant to petrological composition and tectonic process. An Internet Database of Rock Seismic Properties (DRSP) was set up and a Handbook of Seismic Properties of Minerals, Rocks and Ores was published. They comprise almost all data available in the literature during the past 4 decades and can serve as a convenient, comprehensive and concise information source on physical properties of rocks to the earth sciences and geotechnical communities. Statistical results of the DRSP reveal the dependence of seismic properties on density, porosity, humidity, and mineralogical and chemical compositions. Using 16 different averaging methods, we calculated P-wave velocities of 696 dry samples according to the volume fraction and elastic constants of each constituent mineral. Although only 22 common minerals were taken into account in the computation, the calculated P-wave velocities agree well with laboratory values measured at about 300 MPa, where most microcracks are closed and the mean Vp of a polymineralic rock is exclusively controlled by its modal composition. However, none of these mixture rules can simultaneously fit measured P-wave velocities for all lithologies or at all pressures. Therefore, more prudence is required in selecting an appropriate mixture rule for calculation of seismic velocities of different rock types.

  4. Towards a geomechanics classification of folded layered rock masses

    Science.gov (United States)

    Agliardi, Federico; Zanchi, Andrea; Bianchi, Federico; Crosta, Giovanni B.

    2016-04-01

    Several schemes have been proposed in the last decades to account for the effects of structure and alteration of rock masses on their geo-mechanical properties. Among these, the Geological Strength Index (GSI) turned out as the most effective to account for complex geological conditions, including heavily fractured, heterogeneous (e.g. flysch-like) or tectonically disturbed rock masses. It is well known that folding has a direct impact on the type and degree of fracturing. Nevertheless, no classification scheme has been developed to introduce explicitly the effects of folding and associated fracturing on rock mass strength and deformability. In this perspective, we carried out an exploratory study aimed at establishing relationships between outcrop-scale folding and GSI in layered carbonate rock masses, exceptionally well exposed in a quarry near Bergamo (Lombardia, Southern Alps). A N-S trending, 350m long and 115m high benched rock face exposes a complete cross section of a sub-horizontal inclined fold involving Lower Jurassic cherty mudstones (Moltrasio Lms.) and marly limestones successions (Domaro Lms.). The main fold has an axial surface moderately dipping to the north and is characterised by polyharmonic folds at scales of metres to tens of metres. The site was documented by producing a digital outcrop through a high-resolution terrestrial photogrammetric survey from distances ranging from 70 to 130 m (18 camera stations, 395 pictures), using RTK GNSS measurements for camera station geo-referencing. Data processing by Structure-from-Motion (SfM) techniques resulted in detailed point clouds covering the entire slope with a cm-scale accuracy. In order to establish relationships between lithology, folding styles, and geomechanical properties of folded rock masses we performed a detailed structural analysis at 25 survey stations spread over all the different fold sectors. These surveys include: lithology, bedding attitude and thickness, brittle structures (e

  5. Origin of inert gases in 'rusty rock' 66095. [lunar contamination hypothesis

    Science.gov (United States)

    Heymann, D.; Huebner, W.

    1974-01-01

    The amount of trapped inert gases present in rock 66095, as well as the elemental and isotopic composition of these gases can be explained by 'contamination' of this rock - on the lunar surface - with as little as 0.2% of fines. There is no compelling evidence that these gases come from the impact of a comet or a carbonaceous meteorite on the moon, or that they represent genuine primordial lunar gas. The Ne-21 radiation age of 66095 is 1.1 plus or minus 0.5 m.y., which strongly suggests that this rock was excavated by the South Ray Crater event.

  6. Rock burst proneness prediction by acoustic emission test during rock deformation

    Institute of Scientific and Technical Information of China (English)

    张志镇; 高峰; 尚晓吉

    2014-01-01

    Rock burst is a severe disaster in mining and underground engineering, and it is important to predict the rock burst risk for minimizing the loss during the constructing process. The rock burst proneness was connected with the acoustic emission (AE) parameter in this work, which contributes to predicting the rock burst risk using AE technique. Primarily, a rock burst proneness index is proposed, and it just depends on the heterogeneous degree of rock material. Then, the quantificational formula between the value of rock burst proneness index and the accumulative AE counts in rock sample under uniaxial compression with axial strain increases is developed. Finally, three kinds of rock samples, i.e., granite, limestone and sandstone are tested about variation of the accumulative AE counts under uniaxial compression, and the test data are fitted well with the theoretic formula.

  7. CERN Rocks

    CERN Document Server

    2004-01-01

    The 15th CERN Hardronic Festival took place on 17 July on the terrace of Rest 3 (Prévessin). Over 1000 people, from CERN and other International Organizations, came to enjoy the warm summer night, and to watch the best of the World's High Energy music. Jazz, rock, pop, country, metal, blues, funk and punk blasted out from 9 bands from the CERN Musiclub and Jazz club, alternating on two stages in a non-stop show.  The night reached its hottest point when The Canettes Blues Band got everybody dancing to sixties R&B tunes (pictured). Meanwhile, the bars and food vans were working at full capacity, under the expert management of the CERN Softball club, who were at the same time running a Softball tournament in the adjacent "Higgs Field". The Hardronic Festival is the main yearly CERN music event, and it is organized with the support of the Staff Association and the CERN Administration.

  8. Are Carious Lesions in Previously Sealed Occlusal Surfaces Detected as well on Colour Photographs as by Visual Clinical Examination?

    NARCIS (Netherlands)

    Hu, X.; Fan, M.; Mulder, J.; Frencken, J.E.

    2016-01-01

    PURPOSE: To compare the level of agreement between carious lesion assessments according to the visual clinical examination and the colour photograph methods. MATERIALS AND METHODS: Data on the presence of enamel/dentin carious lesions in previously sealed occlusal surfaces in first molars were

  9. Overexpression of ROCK1 and ROCK2 inhibits human laryngeal squamous cell carcinoma.

    Science.gov (United States)

    Zhang, Junbo; He, Xue; Ma, Yueying; Liu, Yanli; Shi, Huaiyin; Guo, Weiwei; Liu, Liangfa

    2015-01-01

    Rho-associated coiled-coil containing protein kinase (ROCK) over-expression has been implicated in the progression of many tumor types. The aim of this study was to explore the roles of ROCK1 and ROCK2 in human laryngeal squamous cell carcinoma (LSCC). ROCK1 and ROCK2 expression levels were examined in 50 cases of human LSCC samples by immunohistochemistry. Effects of ROCK1 and ROCK2 on LSCC cell proliferation and motility were investigated in the presence of the ROCK inhibitor Y-27632. The results showed that ROCK1 expression was positively correlated with tumor size and lymph node metastasis (P ROCK2 positively correlated with tumor size (P ROCK2 by Y-27632 significantly inhibits proliferation, migration, and invasion of LSCC cells. Our data indicate that expression of ROCK1 and ROCK2 are closely associated with tumor growth and lymph node metastasis of LSCC. Thus, these two ROCK isoforms may be useful as molecular makers for LSCC diagnosis and may be useful therapeutic targets as well.

  10. Aespoe Hard Rock Laboratory. Annual Report 2009

    Energy Technology Data Exchange (ETDEWEB)

    2010-12-15

    The Aespoe Hard Rock Laboratory (HRL) is an important part of SKB's work with the design and construction of a deep geological repository for the final disposal of spent nuclear fuel. Aespoe HRL is located in the Simpevarp area in the municipality of Oskarshamn. One of the fundamental reasons behind SKB's decision to construct an underground laboratory was to create opportunities for research, development and demonstration in a realistic and undisturbed rock environment down to repository depth. The underground part of the laboratory consists of a tunnel from the Simpevarp peninsula to the southern part of Aespoe where the tunnel continues in a spiral down to a depth of 460 m. Aespoe HRL has been in operation since 1995 and considerable international interest has been shown in its research, as well as in the development and demonstration tasks. A summary of the work performed at Aespoe HRL during 2009 is given below. Geoscience Geoscientific research is a basic activity at Aespoe HRL. The aim of the current studies is to develop geoscientific models of the Aespoe HRL and increase the understanding of the rock mass properties as well as knowledge of applicable methods of measurement. A main task within the geoscientific field is the development of the Aespoe Site Descriptive Model (SDM) integrating information from the different fields. The main activities in the geoscientific fields have been: (1) Geology evaluation of geological mapping techniques leading to the decision to develop a SKB mapping system and finalization of the mapping of rock surfaces in the new tunnel, (2) Hydrogeology monitoring and storage of data in the computerised Hydro Monitoring System, (3) Geochemistry sampling of groundwater in the yearly campaign and for specific experiments and (4) Rock Mechanics finalised the field tests on thermally-induced spalling in deposition holes and evaluated the effect of counterforce in the deposition holes. Natural barriers At Aespoe HRL

  11. Theory and application of infrared surveying gas gushing technology in coal-rock roadway

    Institute of Scientific and Technical Information of China (English)

    蔡康旭

    2002-01-01

    Geological structure and gas expansion when gas pressure was released can affect the distribution of infrared radiation energy or temperature at coal-rock surface. From this, the foundation of roadway infrared surveying technical was formed. According to the thermodynamic principle of ideal gas and the law of energy conservation, the relation was established between gas gushing amount from coal-rock and air temperature to fall in roadway. At the same time, this paper has analyzed coal-rock density change that geological structure aroused and the change exerted influences on infrared radiation power at surface, as well as, has analyzed the infrared radiation feature of gas gushing at geological structure district. Application results show that infrared survey technology can be used to analyze and forecast the change of coal-rock gas gushing effectively, and to guide the enforcement of the roadway gas project of prevention and handling economically.

  12. Effects of Palagonitic Dust Coatings on Thermal Emission Spectra of Rocks and Minerals: Implications for Mineralogical Characterization of the Martian Surface by MGS-TES

    Science.gov (United States)

    Graff, T. G.; Morris, R.; Christensen, P.

    2001-01-01

    Thermal emission measurements on dust-coated rocks and minerals show that a 300 5m thick layer is required to mask emission from the substrate and that non-linear effects are present. Additional information is contained in the original extended abstract.

  13. Hydrology of some deep mines in Precambrian rocks

    Energy Technology Data Exchange (ETDEWEB)

    Yardley, D.H.

    1975-10-01

    A number of underground mines were investigated during the summer of 1975. All of them are in Precambrian rocks of the Lake Superior region. They represent a variety of geologic settings. The purpose of the investigations was to make a preliminary study of the dryness, or lack of dryness of these rocks at depth. In other words, to see if water was entering the deeper workings through the unmined rock by some means such as fracture or fault zones, joints or permeable zones. Water entering through old mine workings extending to, or very near to the surface, or from the drilling equipment, was of interest only insofar as it might mask any water whose source was through the hanging or footwall rocks. No evidence of running, seeping or moving water was seen or reported at depths exceeding 3,000 feet. At depths of 3,000 feet or less, water seepages do occur in some of the mines, usually in minor quantities but increased amounts occur as depth becomes less. Others are dry at 2,000 feet of depth. Rock movements associated with extensive mining should increase the local secondary permeability of the rocks adjoining the mined out zones. Also most ore bodies are located where there has been a more than average amount of faulting, fracturing, and folding during the geologic past. They tend to cluster along crustal flows. In general, Precambrian rocks of similar geology, to those seen, well away from zones that have been disturbed by extensive deep mining, and well away from the zones of more intense geologic activity ought to be even less permeable than their equivalents in a mining district.

  14. Body-rock or lift-off in flow

    CERN Document Server

    Smith, Frank T

    2013-01-01

    Conditions are investigated under which a body lying at rest or rocking on a solid horizontal surface can be removed from the surface by hydrodynamic forces or instead continues rocking. The investigation is motivated by recent observations on Martian dust movement as well as other small- and large-scale applications. The nonlinear theory of fluid-body interaction here has unsteady motion of an inviscid fluid interacting with a moving thin body. Various shapes of body are addressed together with a range of initial conditions. The relevant parameter space is found to be subtle as evolution and shape play substantial roles coupled with scaled mass and gravity effects. Lift-off of the body from the surface generally cannot occur without fluid flow but it can occur either immediately or within a finite time once the fluid flow starts up: parameters for this are found and comparisons are made with Martian observations.

  15. Electron mobility limited by surface and interface roughness scattering in AlxGa1-xN/GaN quantum wells

    Institute of Scientific and Technical Information of China (English)

    Wang Jian-Xia; Yang Shao-Yan; Wang Jun; Liu Gui-Peng; Li Zhi-Wei; Li Hui-Jie; Jin Dong-Dong

    2013-01-01

    The electron mobility limited by the interface and surface roughness scatterings of the two-dimensional electron gas in AlxGa1-xN/GaN quantum wells is studied.The newly proposed surface roughness scattering in the AlGaN/GaN quantum wells becomes effective when an electric field exists in the AlxGal-xN barrier.For the AlGaN/GaN potential well,the ground subband energy is governed by the spontaneous and the piezoelectric polarization fields which are determined by the barrier and the well thicknesses.The thickness fluctuation of the AlGaN barrier and the GaN well due to the roughnesses cause the local fluctuation of the ground subband energy,which will reduce the 2DEG mobility.

  16. Spatial distribution of rock glaciers in the semi-arid Andes of Argentina

    Science.gov (United States)

    Blöthe, Jan Henrik; Halla, Christian; Schrott, Lothar; Götz, Joachim; Trombotto, Dario

    2016-04-01

    Active rock glaciers are indicators for permafrost in periglacial environments of high mountain areas. Within the permafrost body and the seasonally frozen active layer, these rock glaciers potentially store large amounts of water. Especially in semiarid mountain belts, such as the central Andes of Argentina, rock glaciers attain several kilometres in length, covering surface areas of >106 m2. Here, rock glaciers even outrange ice glaciers in cumulative area and absolute number, indicating they might constitute a large water reservoir in this semiarid part of the Andes. Despite their potential hydrological importance, our knowledge about the rock glaciers' spatial distribution, subsurface composition and absolute ice content is still very limited. Our study addresses this shortcoming and aims at assessing the hydrological significance of rock glacier permafrost in the semi-arid Andes of Argentina by combining local geophysical investigations with regional remote sensing analysis. Our research focuses on the central Andes between 30°S and 33°S, where we have compiled an inventory that comprises more than 1200 rock glaciers, as well as 154 clear-ice and debris-covered glaciers. Two field sites that bracket this regional study area towards their northern and southern edge have been selected for local geophysical investigations. At these locations, earlier studies detected the presence of rock glacier permafrost by thermal monitoring and geophysical prospection. Preliminary results of the regional spatial distribution indicate that the spatial density of rock glaciers increases towards the south, concomitant with a twofold increase in mean annual precipitation. Rock glacier density peaks in the area of the Aconcagua massif, while precipitation is further increasing towards the south. Simultaneously, the lower altitudinal limit of intact rock glaciers slightly decreases, with the lowest rock glacier toe positions in the northern study area located at ~3800 m a. s. l

  17. 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.

  18. 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

  19. Turbulent clustering of initially well-mixed buoyant particles on a free-surface by Lagrangian coherent structures

    Science.gov (United States)

    Pratt, Kenneth R.; True, Aaron; Crimaldi, John P.

    2017-07-01

    Particles that float on the surface of a 3D incompressible turbulent flow are exposed to non-divergence-free properties that result in clustering and unmixing, a reversal of how turbulence normally acts to mix and dilute scalars. Particle clustering is dominated by Lagrangian processes that depend on the time history of the flow; this suggests that Lagrangian coherent structures (LCS) might serve as templates for cluster formation. In this study, non-divergence-free clustering is examined both experimentally and numerically to elucidate the role of LCS in the formation of particle clusters and voids. Experiments are performed on the free-surface of a water-filled tank with turbulence driven by the random pulsing of centrifugal pumps on the tank bottom. Clustering is quantified by imaging fluorescent, buoyant particles that are placed in an initially random distribution on the free-surface. Within clusters, concentrations are observed to increase by an order of magnitude, with the likelihood of observing enhanced concentrations increasing by two orders of magnitude. LCS, obtained from velocity fields utilizing particle image velocimetry, are shown to act as templates for cluster formation. In addition, LCS are shown to possess a dilatation component in non-divergence-free flows that is responsible for unmixing. Numerically, a non-divergence-free chaotic model consisting of interacting Taylor vortices is utilized to investigate processes responsible for cluster formation seen in the experiments. The model results support the experimental finding that LCS act as templates for particle clusters, with scalar unmixing driven by the dilatation component.

  20. Influence of near-field coupling from Ag surface plasmons on InGaN/GaN quantum-well photoluminescence

    DEFF Research Database (Denmark)

    Fadil, Ahmed; Iida, Daisuke; Chen, Yuntian

    2016-01-01

    We have investigated the borderline between photoluminescence quenching and enhancement of InGaN/GaN quantum-wells due to Ag nanoparticles and their surface plasmon modes. By embedding Ag nanoparticles inside nanohole structures on the p-type layer GaN, luminescence quenching is observed.Increasi......We have investigated the borderline between photoluminescence quenching and enhancement of InGaN/GaN quantum-wells due to Ag nanoparticles and their surface plasmon modes. By embedding Ag nanoparticles inside nanohole structures on the p-type layer GaN, luminescence quenching is observed...

  1. Are Carious Lesions in Previously Sealed Occlusal Surfaces Detected as well on Colour Photographs as by Visual Clinical Examination?

    Science.gov (United States)

    Hu, Xuan; Fan, Mingwen; Mulder, Jan; Frencken, Jo E

    2016-01-01

    To compare the level of agreement between carious lesion assessments according to the visual clinical examination and the colour photograph methods. Data on the presence of enamel/dentin carious lesions in previously sealed occlusal surfaces in first molars were obtained by two trained and calibrated examiners through visual clinical examination and from colour photographs 4 years after sealing. Kappa statistics were applied to calculate agreement between assessment methods. Data analysis was performed using sign, Bowker symmetry and McNemar's tests. The prevalence of dentin carious lesions was very low. The kappa coefficients for detecting enamel/dentin carious lesions using the two assessment methods were 0.65 (CI: 0.56-0.74) for examiner 1 and 0.70 (CI: 0.62-0.78) for examiner 2. Examiner 2 observed more enamel/dentin carious lesions on colour photographs than did examiner 1 (p = 0.008). Sensitivity analyses did not confirm this outcome. There was no difference in the detection of enamel/dentin carious lesions in previously sealed occlusal surfaces using colour photographs vs visual clinical examination. The colour photograph method is therefore equivalent to the visual clinical examination in detecting enamel/dentin carious lesions. More studies are required.

  2. Rollerjaw Rock Crusher

    Science.gov (United States)

    Peters, Gregory; Brown, Kyle; Fuerstenau, Stephen

    2009-01-01

    The rollerjaw rock crusher melds the concepts of jaw crushing and roll crushing long employed in the mining and rock-crushing industries. Rollerjaw rock crushers have been proposed for inclusion in geological exploration missions on Mars, where they would be used to pulverize rock samples into powders in the tens of micrometer particle size range required for analysis by scientific instruments.

  3. Tensile Strength of Geological Discontinuities Including Incipient Bedding, Rock Joints and Mineral Veins

    Science.gov (United States)

    Shang, J.; Hencher, S. R.; West, L. J.

    2016-11-01

    Geological discontinuities have a controlling influence for many rock-engineering projects in terms of strength, deformability and permeability, but their characterisation is often very difficult. Whilst discontinuities are often modelled as lacking any strength, in many rock masses visible rock discontinuities are only incipient and have tensile strength that may approach and can even exceed that of the parent rock. This fact is of high importance for realistic rock mass characterisation but is generally ignored. It is argued that current ISRM and other standards for rock mass characterisation, as well as rock mass classification schemes such as RMR and Q, do not allow adequately for the incipient nature of many rock fractures or their geological variability and need to be revised, at least conceptually. This paper addresses the issue of the tensile strength of incipient discontinuities in rock and presents results from a laboratory test programme to quantify this parameter. Rock samples containing visible, natural incipient discontinuities including joints, bedding, and mineral veins have been tested in direct tension. It has been confirmed that such discontinuities can have high tensile strength, approaching that of the parent rock. Others are, of course, far weaker. The tested geological discontinuities all exhibited brittle failure at axial strain less than 0.5 % under direct tension conditions. Three factors contributing to the tensile strength of incipient rock discontinuities have been investigated and characterised. A distinction is made between sections of discontinuity that are only partially developed, sections of discontinuity that have been locally weathered leaving localised residual rock bridges and sections that have been `healed' through secondary cementation. Tests on bedding surfaces within sandstone showed that tensile strength of adjacent incipient bedding can vary considerably. In this particular series of tests, values of tensile strength

  4. Variability of surface characteristics and energy flux patterns of sunn hemp ( Crotalaria juncea L.) under well-watered conditions

    Science.gov (United States)

    Takagi, Keiko; Kimura, Reiji; Şaylan, Levent

    2009-05-01

    There is not much information in the literature about the energy partitioning and micrometeorological features of sunn hemp. Therefore, in this study, the variations in the energy-balance components and plant characteristics such as aerodynamic and surface conductance, crop coefficient, albedo, short- and long wave down- and upward radiation have been measured and estimated for the time period from August to October 2004 over an irrigated sand field at the Arid Land Research Center in Tottori, Japan. The Bowen ratio energy-balance method was used to calculate the partitioning of heat fluxes of sunn hemp. The Bowen ratio values at the first growing stages in August were found to be higher than the Bowen ratio values at the latest growing stages in September and October because of the heavy rain and high soil-water content. The daytime averaged Bowen ratio was 0.19. During the measurement period, the daytime average net radiation, and soil, latent and sensible heat fluxes were approximately 231, 28, 164, and 39 W m-2, respectively. The net radiation and soil heat flux showed decreasing trends from the beginning to the end of the experiment period due to the atmospheric and crop growth conditions. The daytime averages of aerodynamic and surface conductance for sunn hemp were around 31 and 17 mm s-1, respectively. Also, the daytime average albedo of sunn hemp was around 19%. Finally, the high precipitation amount due to typhoons, high soil-water content, low available energy and low vapor-pressure deficit lead to decreasing trend of the energy fluxes during the generative phase of sunn hemp.

  5. Tracing surface water infiltration in fractured rocks with environmental isotopes: a case study of the former Balangero asbestos mine (northern Italy)

    Energy Technology Data Exchange (ETDEWEB)

    Sacchi, Elisa [University of Pavia, Via Ferrata 1, Pavia I-27100 (Italy); Bergamini, Massimo; Castellano, Gianpaolo [R.S.A. S.r.l, Viale Copperi 15, Balangero - TO, I-10070 (Italy); Barella, Vittorio [ISO4 S.n.c., Via Valperga Caluso 37, Torino I-10125 (Italy)

    2013-07-01

    A semi-quantitative evaluation of the contribution of lake water to streams, springs, and groundwater circulating in the fractured rocks hosting the former Balangero asbestos mine was performed using stable isotopes of the water molecule. Results indicate that the lake, located in the open pit of the mine, generally contributes less than 30% of water to streams, springs, and groundwater. This contribution is more evident during dry periods, and should be taken into account in the design of remediation plans. (authors)

  6. Plasmons in a free-standing nanorod with a two-dimensional parabolic quantum well caused bv surface states

    Institute of Scientific and Technical Information of China (English)

    Song Ya-Feng; Lü Yan-Wu; Wen Wei; Liu Xiang-Lin; Yang Shao-Yan; Zhu Qin-Sheng; Wang Zhan-Guo

    2012-01-01

    The collective charge density excitations in a free-standing nanorod with a two-dimensional parabolic quantum well are investigated within the framework of Bohm-Pine's random-phase approximation in the two-subband model.The new simplified analytical expressions of the Coulomb interaction matrix elements and dielectric functions are derived and numerically discussed.In addition,the electron density and temperature dependences of dispersion features are also investigated.We find that in the two-dimensional parabolic quantum well,the intrasubband upper branch is coupled with the intersubband mode,which is quite different from other quasi-one-dimensional systems like a cylindrical quantum wire with an infinite rectangular potential.In addition,we also find that higher temperature results in the intersubband mode(with an energy of 12 meV(~3 THz))becoming totally damped,which agrees well with the experimental results of Raman scattering in the literature.These interesting properties may provide useful references to the design of free-standing nanorod based devices.

  7. Approximate solutions of the equation of motion’s of the rigid rod which rocks on the circular surface without slipping

    Directory of Open Access Journals (Sweden)

    Md. Alal Hosen

    2014-09-01

    Full Text Available In this paper, a modified harmonic balance method based an analytical technique has been developed to determine approximate solutions for a strongly nonlinear oscillator with a discontinuous term which is arising from the motion of rigid rod on the surface without slipping. Usually, a set of nonlinear algebraic equations is solved in this method. However, analytical solutions of these algebraic equations are not always possible, especially in the case of a large oscillation. We have been compared the solution results of this method with the numerical solution in order to validate the approach and assess the accuracy of the solutions has been demonstrated and discussed. We found that, a second order modified harmonic balance method works very well for the whole range of initial amplitudes. The advantage of the using method is its simple procedure and gives almost similar results in comparison with the exact solution.

  8. Modelling nitrate from land-surface to wells-perforations under Mediterranean agricultural land: success, failure, and future scenarios

    Science.gov (United States)

    Levy, Yehuda; Chefetz, Benny; Shapira, Roi; Kurtzman, Daniel

    2017-04-01

    Contamination of groundwater resources by nitrate due to leaching under agricultural land is probably the most troublesome agriculture-related water contamination, worldwide. Deep soil sampling (10 m) were used for calibrating vertical flow and nitrogen-transport numerical models of the unsaturated zone, under different agricultural land uses. Vegetables fields (potato and strawberries) and deciduous (persimmon) orchards in the Sharon area overlaying the coastal aquifer of Israel, were examined. Average nitrate-nitrogen fluxes below vegetables fields were 210-290 kg ha-1 a-1 and under deciduous orchards were 110-140 kg ha-1 a-1. The output water and nitrate-nitrogen fluxes of the unsaturated zone models were used as input for a three dimensional flow and nitrate-transport model in the aquifer under an area of 13.3 square kilometers of agricultural land. The area was subdivided to 4 agricultural land-uses: vegetables, deciduous, citrus orchards and non-cultivated. Fluxes of water and nitrate-nitrogen below citrus orchards were taken from a previous study in this area (Kurtzman et al., 2013, j. Contam. Hydrol.). The groundwater flow model was calibrated to well heads only by changing the hydraulic conductivity while transient recharge fluxes were constraint to the bottom-fluxes of the unsaturated zone flow models. The nitrate-transport model in the aquifer, which was fed at the top by the nitrate fluxes of the unsaturated zone models, succeeded in reconstructing the average nitrate concentration in the wells. On the other hand, this transport model failed in calculating the high concentrations in the most contaminated wells and the large spatial variability of nitrate-concentrations in the aquifer. In order to reconstruct the spatial variability and enable predictions nitrate-fluxes from the unsaturated zone were multiplied by local multipliers. This action was rationalized by the fact that the high concentrations in some wells cannot be explained by regular

  9. Rock damage caused by underground excavation and meteorite impacts

    OpenAIRE

    Bäckström, Ann

    2008-01-01

    The intent of this thesis is to contribute to the understanding of the origin of fractures in rock. The man-made fracturing from engineering activities in crystalline rock as well as the fracturing induced by the natural process of meteorite impacts is studied by means of various characterization methods. In contrast to engineering induced rock fracturing, where the goal usually is to minimize rock damage, meteorite impacts cause abundant fracturing in the surrounding bedrock. In a rock mass ...

  10. Fault rock mineralogy and fluid flow in the Coso Geothermal Field, CA

    Science.gov (United States)

    Davatzes, N. C.; Hickman, S. H.

    2005-12-01

    to differ because the processes that accommodate deformation depend strongly on mineralogy. Frictional strength of quartz-dominated fault rocks in the near surface and in the reservoir should be greater (~0.6) than that in the clay-dominated cap rock (~0.2-0.4). Similarly, permeability should be much lower in foliated clay-rich fault rocks than in quartz-rich fault rocks as evidenced by larger, more connected pores imaged in quartz-rich gouge. Mineral stability is a function of loading, strain rate, temperature, and fluid flow conditions. Which minerals form, and the rates at which they grow is also a key element in determining variations in the magnitude and anisotropy of fault zone properties at Coso. Consequently, we suggest that the development of fault-zone properties depends on the feedback between deformation, resulting changes in permeability, and large-scale fluid flow and the leading to dissolution/precipitation of minerals in the fault rock and adjacent host rock. The implication for Coso is that chemical alteration of otherwise low-porosity crystalline rocks appears to determine the distribution and temporal evolution of permeability in the actively deforming fracture network at small to moderate scales as well as along major, reservoir-penetrating fault zones.

  11. Protein adsorption at polymer-grafted surfaces : Comparison between a mixture of saliva proteins and some well-defined model proteins

    NARCIS (Netherlands)

    Kawasaki, K; Kambara, M; Matsumura, H; Norde, W

    2003-01-01

    Grafting a dense layer of soluble polymers onto a surface is a well-established method for controlling protein adsorption. In the present study, polyethylene oxide (PEO) layers of three different grafting densities were prepared, i.e. 10-15 nm(2), 5.5 nm(2) and 4 nm(2) per polymer chain, respectivel

  12. Protein adsorption at polymer-grafted surfaces: Comparison between a mixture of saliva proteins and some well-defined model proteins

    NARCIS (Netherlands)

    Kawasaki, K.; Kambara, M.; Matsumura, H.; Norde, W.

    2003-01-01

    Grafting a dense layer of soluble polymers onto a surface is a well-established method for controlling protein adsorption. In the present study, polyethylene oxide (PEO) layers of three different grafting densities were prepared, i.e. 10-15 nm2, 5.5 nm2 and 4 nm2 per polymer chain, respectively. The

  13. The Potential Well-Depth $U^{(N)}_{\\Sigma}$ Constraints on the Surface Gravitational Red-shift of a Proto Neutron Star

    Indian Academy of Sciences (India)

    Xian-Feng Zhao

    2011-09-01

    The influence of the potential well depth $U^{(N)}_{\\Sigma}$ of in nuclear matter on the surface gravitational red-shift of a proto neutron star is examined within the framework of the relativistic mean field theory for the baryon octet system. It is found that as $U^{(N)}_{\\Sigma}$ increases from -35 MeV to +35 MeV, the surface gravitational red-shift increases and the influence of the negative $U^{(N)}_{\\Sigma}$ on the surface gravitational red-shift is larger than that of the positive ones. Furthermore, the max/ and the surface gravitational red-shift corresponding to the maximum mass all increase as the $U^{(N)}_{\\Sigma}$ increases, max and being the maximum mass of the proto neutron star and the corresponding radius respectively.

  14. Tunable localized surface plasmon resonances in one-dimensional h-BN/graphene/h-BN quantum-well structure

    Science.gov (United States)

    Kaibiao, Zhang; Hong, Zhang; Xinlu, Cheng

    2016-03-01

    The graphene/hexagonal boron-nitride (h-BN) hybrid structure has emerged to extend the performance of graphene-based devices. Here, we investigate the tunable plasmon in one-dimensional h-BN/graphene/h-BN quantum-well structures. The analysis of optical response and field enhancement demonstrates that these systems exhibit a distinct quantum confinement effect for the collective oscillations. The intensity and frequency of the plasmon can be controlled by the barrier width and electrical doping. Moreover, the electron doping and the hole doping lead to very different results due to the asymmetric energy band. This graphene/h-BN hybrid structure may pave the way for future optoelectronic devices. Project supported by the National Natural Science Foundation of China (Grant Nos. 11474207 and 11374217) and the Scientific Research Fund of Sichuan University of Science and Engineering, China (Grant No. 2014PY07).

  15. Coupled gas flow/solid dynamics model for predicting the formation of fracture patterns in gas well simulation experiments. [Propellant mixture used instead of explosives to fracture rock surrounding borehole

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, L.M.; Swenson, D.V.; Cooper, P.W.

    1984-07-01

    A two-dimensional finite element model for predicting fracture patterns obtained in high energy gas fracture experiments is presented. In these experiments, a mixture of propellants is used instead of explosives to fracture the rock surrounding the borehole. The propellant mixture is chosen to tailor the pressure pulse so that multiple fractures emanate from the borehole. The model allows the fracture pattern and pressure pulse to be calculated for different combinations of propellant mixture, in situ stress conditions, and rock properties. The model calculates the amount of gas generated by the burning propellants using a burn rate given by a power law in pressure. By assuming that the gas behaves as a perfect gas and that the flow down the fractures is isothermal, the loss of gas from the borehole due to flow down the cracks is accounted for. The flow of gas down the cracks is included in an approximate manner by assuming self-similar pressure profiles along the fractures. Numerical examples are presented and compared to three different full-scale experiments. Results show a good correlation with the experimental data over a wide variety of test parameters. 9 reference, 10 figures, 3 tables.

  16. In Situ Evaluation of Water-Rock Reactions during Carbon Dioxide Injection in Basaltic and Metasedimentary Rocks

    Science.gov (United States)

    Matter, J. M.; Assayag, N.; Goldberg, D.; Takahashi, T.

    2006-12-01

    Large differences between laboratory and field derived mineral reaction rates underscore the importance of evaluating mineral-fluid reactions under in situ conditions in a natural environment. This study investigates the extent of in situ water-rock reactions in basaltic and metasedimentary rocks (rich in Ca, Mg silicates) after the injection of CO2 enriched water, with the objective of providing information pertinent to permanent storage of anthropogenic CO2 in geologic reservoirs. CO2 injections were conducted using a single-well push-pull testing strategy. CO2 saturated water (pH 3.5) was injected into a hydraulically isolated and permeable aquifer in a 300-m experimental borehole. Water samples were retrieved after the CO2 injection. Mass transfer terms for Ca, Mg, Na, and Si were determined by using the measured ion concentrations. Using the mass balance, the weeks-long incubation time of the injected solution, and geometric estimates of the reactive surface area of the host rocks, in situ bulk rock dissolution rates of aquifer material were estimated. In addition, δ13C data coupled with total CO2 concentration were used as a tracer to quantitatively evaluate processes such as carbonate dissolution and precipitation, oxidation of organic matter and biological activity within the aquifer. Results show that the injected CO2 was neutralized within several days by two processes; mixing with aquifer water, and rock-water reactions. Calculated bulk rock dissolution rates decrease with increasing pH. The pH dependence of the dissolution rate for Ca is twice as large as for Mg, strongly favoring Ca release and possibly suggesting an additional source of Ca besides silicate minerals. Analyses of δ13C on water and rock samples confirm dissolution of calcium carbonates within the aquifer.

  17. Nanoscale Compositional Relations in Lunar Rock Patina: Deciphering Sources for Patina Components on an Apollo 17 Station 6 Boulder

    Science.gov (United States)

    Christoffersen, R.; Noble, S. K.; Keller, L. P.

    2014-01-01

    Space weathering on the Moon and other airless bodies modifies the surfaces of regolith grains as well as the space-exposed surfaces of larger rocks and boulders. As space weathering witness plates, rocks and boulders are distinguished from regolith grains based on their ability to persist as physically intact substrates over longer time scales before being disaggregated by impact processes. Because lunar surfaces, including exposed rocks, quickly develop an optically thick layer of patina, it is important to understand the compositional relationship between patinas and their underlying rock substrates, particularly to support remote-sensing of rocky lunar terrains. Based on analytical TEM techniques, supported by focused ion beam (FIB) cross-sectioning, we have begun to systematize the multi-layer microstructural complexity of patinas on rock samples with a range of space exposure histories. Our on-going work has particularly focused on lunar rock 76015, both because it has a long (approx. 22 my) exposure history, and because its surface was exposed to patina development approximately 1 m off the regolith surface on a boulder in the Apollo 17 Station 6 boulder field. Potential sources for the 76015 patina therefore include impact-melted and vaporized material derived from the local rock substrate, as well as from the mix of large boulders and regolith in the Station 6 area. While similar, there are differences in the mineralogy and chemistry of the rocks and regolith at Station 6. We were interested to see if these, or other sources, could be distinguished in the average composition, as well as the compositional nanostratigraphy of the 76015 patina. To date we have acquired a total of 9 TEM FIB cross-sections from the 76015 patina, giving us reasonable confidence of being able to arrive at an integrated average for the patina major element composition based on analytical TEM methods.

  18. Corrective Action Investigation plan for Corrective Action Unit 546: Injection Well and Surface Releases, Nevada Test Site, Nevada, Revision 0

    Energy Technology Data Exchange (ETDEWEB)

    Alfred Wickline

    2008-03-01

    Corrective Action Unit (CAU) 546 is located in Areas 6 and 9 of the Nevada Test Site, which is approximately 65 miles northwest of Las Vegas, Nevada. Corrective Action Unit 546 is comprised of two Corrective Action Sites (CASs) listed below: •06-23-02, U-6a/Russet Testing Area •09-20-01, Injection Well These sites are being investigated because existing information on the nature and extent of potential contamination is insufficient to evaluate and recommend corrective action alternatives. Additional information will be obtained by conducting a corrective action investigation (CAI) before evaluating corrective action alternatives and selecting the appropriate corrective action for each CAS. The results of the field investigation will support a defensible evaluation of viable corrective action alternatives that will be presented in the Corrective Action Decision Document. The sites will be investigated based on the data quality objectives (DQOs) developed on November 8, 2007, by representatives of the Nevada Division of Environmental Protection and U.S. Department of Energy (DOE), National Nuclear Security Administration Nevada Site Office. The DQO process has been used to identify and define the type, amount, and quality of data needed to develop and evaluate appropriate corrective actions for CAU 546.

  19. Hot dry rock geothermal energy

    Science.gov (United States)

    Heiken, G.; Murphy, H.; Nunz, G.; Potter, R.

    1981-08-01

    Man-made geothermal systems are discussed which make it possible to extract heat from hot rocks in areas where natural fluids are insufficient for the development of hydrothermal energy. The location and magnitude of high- and low-temperature geothermal resources in the USA for such hot dry rock (HDR) systems are examined. An HDR concept is described in which water is injected into one of two nearly parallel wells connected at depth by man-made fractures; the injected water circulates through the fracture system, where it is heated by conduction from the hot rock, and hot fluid, which can be used for heating or for electric power generation, rises through the second well. Some heat-extraction experiments using the described concept are reviewed which are being conducted in a complex volcanic field in New Mexico. The economics of HDR energy is evaluated.

  20. Ultrafast all-optical switching and error-free 10 Gbit/s wavelength conversion in hybrid InP-silicon on insulator nanocavities using surface quantum wells

    Energy Technology Data Exchange (ETDEWEB)

    Bazin, Alexandre; Monnier, Paul; Beaudoin, Grégoire; Sagnes, Isabelle; Raj, Rama [Laboratoire de Photonique et de Nanostructures (CNRS UPR20), Route de Nozay, Marcoussis 91460 (France); Lenglé, Kevin; Gay, Mathilde; Bramerie, Laurent [Université Européenne de Bretagne (UEB), 5 Boulevard Laënnec, 35000 Rennes (France); CNRS-Foton Laboratory (UMR 6082), Enssat, BP 80518, 22305 Lannion Cedex (France); Braive, Rémy; Raineri, Fabrice, E-mail: fabrice.raineri@lpn.cnrs.fr [Laboratoire de Photonique et de Nanostructures (CNRS UPR20), Route de Nozay, Marcoussis 91460 (France); Université Paris Diderot, Sorbonne Paris Cité, 75207 Paris Cedex 13 (France)

    2014-01-06

    Ultrafast switching with low energies is demonstrated using InP photonic crystal nanocavities embedding InGaAs surface quantum wells heterogeneously integrated to a silicon on insulator waveguide circuitry. Thanks to the engineered enhancement of surface non radiative recombination of carriers, switching time is obtained to be as fast as 10 ps. These hybrid nanostructures are shown to be capable of achieving systems level performance by demonstrating error free wavelength conversion at 10 Gbit/s with 6 mW switching powers.

  1. Fossils, rocks, and time

    Science.gov (United States)

    Edwards, Lucy E.; Pojeta, John

    1999-01-01

    We study our Earth for many reasons: to find water to drink or oil to run our cars or coal to heat our homes, to know where to expect earthquakes or landslides or floods, and to try to understand our natural surroundings. Earth is constantly changing--nothing on its surface is truly permanent. Rocks that are now on top of a mountain may once have been at the bottom of the sea. Thus, to understand the world we live on, we must add the dimension of time. We must study Earth's history. When we talk about recorded history, time is measured in years, centuries, and tens of centuries. When we talk about Earth history, time is measured in millions and billions of years. Time is an everyday part of our lives. We keep track of time with a marvelous invention, the calendar, which is based on the movements of Earth in space. One spin of Earth on its axis is a day, and one trip around the Sun is a year. The modern calendar is a great achievement, developed over many thousands of years as theory and technology improved. People who study Earth's history also use a type of calendar, called the geologic time scale. It looks very different from the familiar calendar. In some ways, it is more like a book, and the rocks are its pages. Some of the pages are torn or missing, and the pages are not numbered, but geology gives us the tools to help us read this book.

  2. Some influences of rock strength and strain rate on propagation of rock avalanches

    Science.gov (United States)

    Bowman, Elisabeth; Rait, Kim

    2016-04-01

    Rock avalanches are extreme and destructive mass movements in which large volumes of rock (typically >1 million cubic metres) travel at high speeds, covering large distances, and the occurrence of which is highly unpredictable. The "size effect" in rock avalanches, whereby those with larger volumes produce greater spreading efficiency (as defined by an increase in normalised runout) or lower farboschung angle (defined as the tangent of the ratio of fall height to runout length), is well known. Studies have shown that rock strength is a controlling factor in the mobility of rock avalanches - that is, mass movements involving lower strength rock are generally found to produce greater mobility as evidenced by the spread of deposits or low farboschung angle. However, there are conflicting ideas as to how and why this influence is manifested. This paper discusses different theories of rock comminution in light of numerical simulations of rock clasts undergoing normal and shear induced loading, experimental work on rock avalanche behaviour, and dynamic fracture mechanics. In doing so, we introduce the idea of thresholds of strain rate for the production of dynamic fragmentation (as opposed to pseudo-static clast crushing) that are based, inter alia, on static rock strength. To do this, we refer to data from physical models using rock analogue materials, field data on chalk cliff collapses, and field statistics from documented rock avalanches. The roles of normal and shear loading and loading rate within a rock avalanche are examined numerically using 3D Discrete Element Method models of rock clasts loaded to failure. Results may help to reconcile the observations that large rock avalanches in stronger materials tend not to fragment as much as those in weaker materials and also possess lower mobility, while small cliff collapses (typically > 1000 cubic metres) in weak chalk can exhibit rock avalanche-like behaviour at much smaller volumes.

  3. Predicting the transport properties of sedimentary rocks from microstructure

    Energy Technology Data Exchange (ETDEWEB)

    Schlueter, Erika M. [Univ. of California, Berkeley, CA (United States)

    1995-01-01

    Understanding transport properties of sedimentary rocks, including permeability, relative permeability, and electrical conductivity, is of great importance for petroleum engineering, waste isolation, environmental restoration, and other applications. These transport properties axe controlled to a great extent by the pore structure. How pore geometry, topology, and the physics and chemistry of mineral-fluid and fluid-fluid interactions affect the flow of fluids through consolidated/partially consolidated porous media are investigated analytically and experimentally. Hydraulic and electrical conductivity of sedimentary rocks are predicted from the microscopic geometry of the pore space. Cross-sectional areas and perimeters of individual pores are estimated from two-dimensional scanning electron microscope (SEM) photomicrographs of rock sections. Results, using Berea, Boise, Massilon, and Saint-Gilles sandstones show close agreement between the predicted and measured permeabilities. Good to fair agreement is found in the case of electrical conductivity. In particular, good agreement is found for a poorly cemented rock such as Saint-Gilles sandstone, whereas the agreement is not very good for well-cemented rocks. The possible reasons for this are investigated. The surface conductance contribution of clay minerals to the overall electrical conductivity is assessed. The effect of partial hydrocarbon saturation on overall rock conductivity, and on the Archie saturation exponent, is discussed. The region of validity of the well-known Kozeny-Carman permeability formulae for consolidated porous media and their relationship to the microscopic spatial variations of channel dimensions are established. It is found that the permeabilities predicted by the Kozeny-Carman equations are valid within a factor of three of the observed values methods.

  4. Exploration of the crystalline underground by extension drilling of the Urach 3 well in the framework of a feasibility study for a hot dry rock demonstration project; Erkundung des kristallinen Untergrunds mit der Vertiefungsbohrung Urach 3 im Rahmen einer Machbarkeitsstudie fuer ein Hot-Dry-Rock-Demonstrationsprojekt

    Energy Technology Data Exchange (ETDEWEB)

    Tenzer, H. [Stadtwerke Bad Urach (Germany); Genter, A.; Hottin, A.M. [BRGM/GIG, Orleans (France)

    1997-12-01

    The prerequisites for specific research into the use of Hot Dry Rock geothermal energy at great depths and temperatures of up to 147 C. In Europe were created with the drilling and completition of the 3334 m deep research drill hole Urach 3 in its phase I (1977/78), and its subsequent extension to 3488 m in phase II (1982/83) within the metamorphic gneiss rock of Urach. A single hole circulation system was tested. Basic results concerning the temperature field, joint system, stress field and hydraulic behavior of the rock were achieved. According to the European HDR guidelines data from depths were a mean reservoir temperature of 175-180 C prevails were necessary to carry out a HDR pilot project. Within the scope of a feasibility study the already existing drill hole Urach 3 was extended from 3488 m to 4445 m depth where the required rock temperature of >170 C was expected. The objective of the project was to determine rock parameters at depth of high temperatures. The bottom hole temperature at true vertical depth of 4394.72 m was determined with 170 C. It can be proved that the temperature gradient is constant with 2.9 K/100 m depth. Due to the results of the investigations it is proposed that the Urach site located in a widespread tectonic horizontal strike-slip system is suitable for a HDR demonstration project. The results can be applied in south German and northern Swiss regions and in other large regions of Europe. Many potential consumers of geothermal energy produced by the HDR concept are situated close around the Urach 3 drill site. (orig./AKF) [Deutsch] Die Forschungsarbeiten zur Weiterentwicklung des Hot-Dry-Rock-Verfahrens begannen am Standort Bad Urach im Jahr 1975. In einer ersten Phase wurde die Bohrung Urach 3 1977/78 auf 3334 m mit einer Gesteinstemperatur von 143 C abgeteuft. Umfangreiche Hydraulische Tests und Frac-Versuche erfolgten. Hiermit wurden die Voraussetzungen fuer die Erkundung des Hot-Dry-Rock-Konzeptes in grossen Tiefen und

  5. Geotechnical Descriptions of Rock and Rock Masses.

    Science.gov (United States)

    1985-04-01

    weathering is presented by Dornbusch (1982). 39. Mechanical, or physical, weathering of rock occurs primarily by (a) freeze expansion (or frost wedging...34Engineering Classifica- tion of In-Situ Rock," Technical Report No. AFWL-TR-67-144, Air Force Weapons Laboratory, Kirtland Air Force Base, N. Mex. Dornbusch , W

  6. Motion of a Rigid Rod Rocking Back and Forth Cubic-Quintic Duffing Oscillators

    DEFF Research Database (Denmark)

    Ganji, S. S.; Barari, Amin; Karimpour, S.

    2012-01-01

    In this work, we implemented the first-order approximation of the Iteration Perturbation Method (IPM) for approximating the behavior of a rigid rod rocking back and forth on a circular surface without slipping as well as Cubic-Quintic Duffing Oscillators. Comparing the results with the exact...

  7. Motion of a Rigid Rod Rocking Back and Forth Cubic-Quintic Duffing Oscillators

    DEFF Research Database (Denmark)

    Ganji, S. S.; Barari, Amin; Karimpour, S.

    2012-01-01

    In this work, we implemented the first-order approximation of the Iteration Perturbation Method (IPM) for approximating the behavior of a rigid rod rocking back and forth on a circular surface without slipping as well as Cubic-Quintic Duffing Oscillators. Comparing the results with the exact...

  8. Measurement of activity concentration of {sup 222}Rn in ground waters drawn from two wells drilled in the Amparo Complex metamorphic rocks, municipio de Amparo, SP; Medida da atividade do {sup 222}Rn em aguas subterraneas extraidas de dois pocos perfurados em rochas metamorficas do Complexo Amparo, municipio de Amparo, SP

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Igor Jose Chaves de

    2008-07-01

    A sampling system was assembled for field {sup 222}Rn activity concentration measurements in ground waters. The system consists of a sampling flask that prevents the contact between the water sample and the atmosphere and a closed line for radon extraction from water. The system, its operation and calibration, are described in full detail, as well as, the conversion of the measured alpha counting rates in activity concentrations. The assembled system was used in {sup 222}Rn activity concentrations measurements in ground waters drawn from two wells drilled in the Amparo Complex metamorphic rocks. The wells are located at the urban area of the city of Amparo and are exploited for public use water. One well, named Vale Verde, is 56 meters deep and crosses 18 meters of soil, 26 meters of quartz rich gneiss and 12 meters of biotite-gneiss. The other well, named Seabra, is 117 meters deep, crosses 28 meters of soil and weathered rocks and ends in granite-gneiss. The mean activity concentrations for the year long observation were (377 +- 25) Bq/dm{sup 3}, for Seabra well, and (1282 +- 57) Bq/dm3, for the Vale Verde well. The {sup 222}Rn activity concentrations fall in the activity concentration range reported in the literature for similar geology areas and are larger than the concentrations found neighboring areas of the same metamorphic Complex. The seasonal activity concentration variations seem to correlate with rain fall variations in the study area. (author)

  9. Ellipsoidal anisotropy in elasticity for rocks and rock masses

    CERN Document Server

    Pouya, Ahmad

    2011-01-01

    One of the interesting features with the ellipsoidal models of anisotropy presented in this paper is their acceptance of analytical solutions for some of the basic elasticity problems. It was shown by Pouya (2000) and Pouya and Zaoui (2006) that many closed-form solutions for basic problems involving linear isotropic materials could be extended by linear transformation to cover a variety of "ellipsoidal" materials. This paper will describe two main varieties of ellipsoidal elastic models and show how well they fit the in situ data for sedimentary rocks; numerical homogenization results for several varieties of fractured rock masses will also be provided.

  10. Preparation for Moving a Rock on Mars

    Science.gov (United States)

    2008-01-01

    The robotic arm on NASA's Phoenix Mars Lander enlarged a trench beside a rock called 'Headless' during the mission's 115th Martian day (Sept. 20, 2008) in preparation for sliding the rock into the trench. The lander's Surface Stereo Imager took this image later that afternoon, showing the enlarged trench and the rock. The robotic arm successfully moved the rock two days later. The Phoenix science team sought to move the rock in order to study the soil and the depth to subsurface ice underneath where the rock had been. Headless is about the size and shape of a VHS videotape. The trench, called 'Neverland,' was excavated to about 3 centimeters (1.2 inches) deep near the rock. The ground surface between the rock and the lip of the trench slopes downward about 3 degrees toward the trench. This image was taken at about 4:35 p.m., local solar time on Mars. The view is to the north northeast of the lander. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by JPL, Pasadena, Calif. Spacecraft development was by Lockheed Martin Space Systems, Denver.

  11. Evolution of Sedimentary Rocks

    Science.gov (United States)

    Veizer, J.; MacKenzie, F. T.

    2003-12-01

    For almost a century, it has been recognized that the present-day thickness and areal extent of Phanerozoic sedimentary strata increase progressively with decreasing geologic age. This pattern has been interpreted either as reflecting an increase in the rate of sedimentation toward the present (Barrell, 1917; Schuchert, 1931; Ronov, 1976) or as resulting from better preservation of the younger part of the geologic record ( Gilluly, 1949; Gregor, 1968; Garrels and Mackenzie, 1971a; Veizer and Jansen, 1979, 1985).Study of the rocks themselves led to similarly opposing conclusions. The observed secular (=age) variations in relative proportions of lithological types and in chemistry of sedimentary rocks (Daly, 1909; Vinogradov et al., 1952; Nanz, 1953; Engel, 1963; Strakhov, 1964, 1969; Ronov, 1964, 1982) were mostly given an evolutionary interpretation. An opposing, uniformitarian, approach was proposed by Garrels and Mackenzie (1971a). For most isotopes, the consensus favors deviations from the present-day steady state as the likely cause of secular trends.This chapter attempts to show that recycling and evolution are not opposing, but complementary, concepts. It will concentrate on the lithological and chemical attributes of sediments, but not deal with the evolution of sedimentary mineral deposits (Veizer et al., 1989) and of life ( Sepkoski, 1989), both well amenable to the outlined conceptual treatment. The chapter relies heavily on Veizer (1988a) for the sections dealing with general recycling concepts, on Veizer (2003) for the discussion of isotopic evolution of seawater, and on Morse and Mackenzie (1990) and Mackenzie and Morse (1992) for discussion of carbonate rock recycling and environmental attributes.

  12. Using earthquake-triggered landslides as a hillslope-scale shear strength test: Insights into rock strength properties at geomorphically relevant spatial scales in high-relief, tectonically active settings

    Science.gov (United States)

    Gallen, Sean; Clark, Marin; Godt, Jonathan; Lowe, Katherine

    2016-04-01

    The material strength of rock is known to be a fundamental property in setting landscape form and geomorphic process rates as it acts to modulate feedbacks between earth surface processes, tectonics, and climate. Despite the long recognition of its importance in landscape evolution, a quantitative understanding of the role of rock strength in affecting geomorphic processes lags our knowledge of the influence of tectonics and climate. This gap stems largely from the fact that it remains challenging to quantify rock strength at the hillslope scale. Rock strength is strongly scale dependent because the number, size, spacing, and aperture of fractures sets the upper limit on rock strength, making it difficult to extrapolate laboratory measurements to landscape-scale interpretations. Here we present a method to determine near-surface rock strength at the hillslope-scale, relying on earthquake-triggered landslides as a regional-scale "shear strength" test. We define near-surface strength as the average strength of rock sample by the landslides, which is typically present results from two well-documented case-studies of earthquakes that caused widespread mass-wasting; the 2008 Mw 7.9 Wenchuan Earthquake, Sichuan Province, China and the 1994 Mw. 6.8 Northridge Earthquake, CA, USA. We show how this model can be used to determine near-surface rock strength and reproduce mapped landslide patterns provided the spatial distribution of local hillslope gradient, earthquake peak ground acceleration (PGA), and coseismic landsliding are well constrained. Results suggest that near-surface rock strength in these tectonically active settings is much lower than that obtained using typical laboratory shear strength measurements on intact rock samples. Furthermore, the near-surface material strength is similar between the study areas despite differences in tectonic, climatic, and lithologic conditions. Variations in near-surface strength within each setting appear to be more strongly

  13. Leak Path Development in CO2 Wells

    Science.gov (United States)

    Torsater, M.; Todorovic, J.; Opedal, N.; Lavrov, A.

    2014-12-01

    Wells have in numerous scientific works been denoted the "weak link" of safe and cost-efficient CO2 Capture and Storage (CCS). Whether they are active or abandoned, all wells are man-made intrusions into the storage reservoir with sealing abilities depending on degradable materials like steel and cement. If dense CO2 is allowed to expand (e.g. due to leakage) it will cool down its surroundings and cause strong thermal and mechanical loading on the wellbore. In addition, CO2 reacts chemically with rock, cement and steel. To ensure long-term underground containment, it is therefore necessary to study how, why, where and when leakage occurs along CO2wells. If cement bonding to rock or casing is poor, leak paths can form already during drilling and completion of the well. In the present work, we have mapped the bonding quality of cement-rock and cement-steel interfaces - and measured their resistance towards CO2 flow. This involved a large experimental matrix including different rocks, steels, cement types and well fluids. The bonding qualities were measured on composite cores using micro computed tomography (µ-CT), and CO2 was flooded through the samples to determine leakage rates. These were further compared to numerical simulations of leakage through the digitalized µ-CT core data, and CO2chemical interactions with the materials were mapped using electron microscopy. We also present a new laboratory set-up for measuring how well integrity is affected by downhole temperature variations - and we showcase some initial results. Our work concludes that leak path development in CO2 wells depends critically on the drilling fluids and presflushes/spacers chosen already during drilling and completion of a well. Fluid films residing on rock and casing surfaces strongly degrade the quality of cement bonding. The operation of the well is also important, as even slight thermal cycling (between 10°C and 95°C on casing) leads to significant de-bonding of the annular cement.

  14. Modeling of Surface Tension and Viscosity for Non-electrolyte Systems by Means of the Equation of State for Square-well Chain Fluids with Variable Interaction Range

    Institute of Scientific and Technical Information of China (English)

    LI Jinlong; HE Changchun; MA Jun; PENG Changjun; LIU Honglai; HU Ying

    2011-01-01

    The equation of state(EOS)for square-well chain fluid with variable range(SWCF-VR) developed in our previous work based on statistical mechanical theory for chemical association is employed for the correlations of surface tension and viscosity of common fluids and ionic liquids(ILs).A model of surface tension for multi-component mixtures is presented by combining the SWCF-VR EOS and the scaled particle theory and used to produce the surface tension of binary and ternary mixtures.The predicted surface tensions are in excellent agreement with the experimental data with an overall average absolute relative deviation(AAD)of 0.36%.A method for the calculation of dynamic viscosity of common fluids and ILs at high pressure is presented by combining Eyring’s rate theory of viscosity and the SWCF-VR EOS.The calculated viscosities are in good agreement with the experimental data with the overall AAD of 1.44% for 14 fluids in 84 cases.The salient feature is that the molecular parameters used in these models are self-consistent and can be applied to calculate different thermodynamic properties such as pVT,vapor-liquid equilibrium,caloric properties,surface tension,and viscosity.

  15. Archaeal diversity and CO2 fixers in carbonate-/siliciclastic-rock groundwater ecosystems

    Science.gov (United States)

    Lazar, Cassandre Sara; Stoll, Wenke; Lehmann, Robert; Herrmann, Martina; Schwab, Valérie F.; Akob, Denise M.; Nawaz, Ali; Wubet, Tesfaye; Buscot, François; Totsche, Kai-Uwe; Küsel, Kirsten

    2017-01-01

    Groundwater environments provide habitats for diverse microbial communities, and although Archaea usually represent a minor fraction of communities, they are involved in key biogeochemical cycles. We analysed the archaeal diversity within a mixed carbonate-rock/siliciclastic-rock aquifer system, vertically from surface soils to subsurface groundwater including aquifer and aquitard rocks. Archaeal diversity was also characterized along a monitoring well transect that spanned surface land uses from forest/woodland to grassland and cropland. Sequencing of 16S rRNA genes showed that only a few surface soil-inhabiting Archaea were present in the groundwater suggesting a restricted input from the surface. Dominant groups in the groundwater belonged to the marine group I (MG-I) Thaumarchaeota and the Woesearchaeota. Most of the groups detected in the aquitard and aquifer rock samples belonged to either cultured or predicted lithoautotrophs (e.g., Thaumarchaeota or Hadesarchaea). Furthermore, to target autotrophs, a series of 13CO2 stable isotope-probing experiments were conducted using filter pieces obtained after filtration of 10,000 L of groundwater to concentrate cells. These incubations identified the SAGMCG Thaumarchaeota and Bathyarchaeota as groundwater autotrophs. Overall, the results suggest that the majority of Archaea on rocks are fixing CO2, while archaeal autotrophy seems to be limited in the groundwater.

  16. My Pet Rock

    Science.gov (United States)

    Lark, Adam; Kramp, Robyne; Nurnberger-Haag, Julie

    2008-01-01

    Many teachers and students have experienced the classic pet rock experiment in conjunction with a geology unit. A teacher has students bring in a "pet" rock found outside of school, and the students run geologic tests on the rock. The tests include determining relative hardness using Mohs scale, checking for magnetization, and assessing luster.…

  17. My Pet Rock

    Science.gov (United States)

    Lark, Adam; Kramp, Robyne; Nurnberger-Haag, Julie

    2008-01-01

    Many teachers and students have experienced the classic pet rock experiment in conjunction with a geology unit. A teacher has students bring in a "pet" rock found outside of school, and the students run geologic tests on the rock. The tests include determining relative hardness using Mohs scale, checking for magnetization, and assessing luster.…

  18. High=porosity Cenozoic carbonate rocks of South Florida: progressive loss of porosity with depth

    Science.gov (United States)

    Halley, Robert B.; Schmoker, James W.

    1983-01-01

    Porosity measurements by borehole gravity meter in subsurface Cenozoic carbonates of South Florida reveal an extremely porous mass of limestone and dolomite which is transitional in total pore volume between typical porosity values for modern carbonate sediments and ancient carbonate rocks. A persistent decrease of porosity with depth, similar to that of chalks of the Gulf Coast, occurs in these rocks. Carbonate strata with less than 20% porosity are absent from the rocks studied here. Aquifers and aquicludes cannot be distinguished on the basis of porosity. Aquifers are not exceptionally porous when compared to other Tertiary carbonate rocks in South Florida. Permeability in these strata is governed more by the spacial distribution of pore space and matrix than by total volume of porosity present. Dolomite is as porous as, or slightly less porous than, limestones in these rocks. This observation places limits on any model proposed for dolomitization and suggests that dolomitization does not take place by a simple ion-for-ion replacement of magnesium for calcium. Dolomitization may be selective for less porous limestone, or it may involve the incorporation of significant amounts of carbonate as well as magnesium into the rock. The great volume of pore space in these rocks serves to highlight the inefficiency of early diagenesis in reducing carbonate porosity and to emphasize the importance of later porosity reduction which occurs during the burial or late near-surface history of limestones and dolomites.

  19. Rock cavern storage of spent fuel

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Won Jin; Kim, Kyung Soo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kwon, Sang Ki [Inha University, Incheon (Korea, Republic of)

    2015-12-15

    The rock cavern storage for spent fuel has been assessed to apply in Korea with reviewing the state of the art of the technologies for surface storage and rock cavern storage of spent fuel. The technical feasibility and economic aspects of the rock cavern storage of spent fuel were also analyzed. A considerable area of flat land isolated from the exterior are needed to meet the requirement for the site of the surface storage facilities. It may, however, not be easy to secure such areas in the mountainous region of Korea. Instead, the spent fuel storage facilities constructed in the rock cavern moderate their demands for the suitable site. As a result, the rock cavern storage is a promising alternative for the storage of spent fuel in the aspect of natural and social environments. The rock cavern storage of spent fuel has several advantages compared with the surface storage, and there is no significant difference on the viewpoint of economy between the two alternatives. In addition, no great technical difficulties are present to apply the rock cavern storage technologies to the storage of domestic spent fuel.

  20. Prediction and Control of Air Flow in Acid-Generating Waste Rock Dumps

    Science.gov (United States)

    Wels, C.; Lefebvre, R.; Robertson, A. M.

    2004-05-01

    Air movement and associated oxygen transport through waste rock dumps has the potential to significantly enhance the rate of oxidation of pyrite-bearing material. While this is a desired outcome for most heap leach operations, airflow in waste rock storage facilities can result in significant increases in generation and acceleration of acid rock drainage. Hence, a good understanding of internal airflow through waste rock dumps is required to control ARD and minimize any associated liability. The principal mechanisms contributing to airflow and oxygen transport in a waste rock pile include (i) diffusion, (ii) advection due to a thermal gradient (chimney effect) and/or wind pressure gradients and (iii) advection due to barometric pumping. While diffusion is typically limited to a near-surface zone of a few meters depth, advection and barometric pumping have the potential to move air (and oxygen) to much greater depths into the pile. In general, the more permeable the waste rock material, and the greater the height-to-width ratio of the waste rock pile, the greater is the potential for advective air movement. The reactivity of the waste rock material as well as the coarseness (hence air permeability), and the spatial variability of these properties within a pile, have a strong influence on the magnitude of thermally induced advection. In contrast, air movement due to barometric pumping is controlled by the waste rock porosity, changes in ambient air pressure and the heterogeneity of air permeability of the waste rock dump. Results of field monitoring and numerical modeling using TOUGH AMD are presented to illustrate the concepts on air movement in waste rock piles. During the design and construction phase, airflow can be controlled by judicious placement of reactive waste rock and use of selective placement techniques to control the internal structure of the waste rock facility (e.g. introduction of horizontal layering, prevention of inclined, high

  1. Induced Polarization Surveying for Acid Rock Screening in Highway Design

    Science.gov (United States)

    Butler, K. E.; Al, T.; Bishop, T.

    2004-05-01

    Highway and pipeline construction agencies have become increasingly vigilant in their efforts to avoid cutting through sulphide-bearing bedrock that has potential to produce acid rock drainage. Blasting and fragmentation of such rock increases the surface area available for sulphide oxidation and hence increases the risk of acid rock drainage unless the rock contains enough natural buffering capacity to neutralize the pH. In December, 2001, the New Brunswick Department of Transportation (NBOT) sponsored a field trial of geophysical surveying in order to assess its suitability as a screening tool for locating near-surface sulphides along proposed highway alignments. The goal was to develop a protocol that would allow existing programs of drilling and geochemical testing to be targeted more effectively, and provide design engineers with the information needed to reduce rock cuts where necessary and dispose of blasted material in a responsible fashion. Induced polarization (IP) was chosen as the primary geophysical method given its ability to detect low-grade disseminated mineralization. The survey was conducted in dipole-dipole mode using an exploration-style time domain IP system, dipoles 8 to 25 m in length, and six potential dipoles for each current dipole location (i.e. n = 1 - 6). Supplementary information was provided by resistivity and VLF-EM surveys sensitive to lateral changes in electrical conductivity, and by magnetic field surveying chosen for its sensitivity to the magnetic susceptibility of pyrrhotite. Geological and geochemical analyses of samples taken from several IP anomalies located along 4.3 line-km of proposed highway confirmed the effectiveness of the screening technique. IP pseudosections from a region of metamorphosed shales and volcaniclastic rocks identified discrete, well-defined mineralized zones. Stronger, overlapping, and more laterally extensive IP anomalies were observed over a section of graphitic and sulphide-bearing metasedimentary

  2. Rock History and Culture

    OpenAIRE

    Gonzalez, Éric

    2013-01-01

    Two ambitious works written by French-speaking scholars tackle rock music as a research object, from different but complementary perspectives. Both are a definite must-read for anyone interested in the contextualisation of rock music in western popular culture. In Une histoire musicale du rock (i.e. A Musical History of Rock), rock music is approached from the point of view of the people – musicians and industry – behind the music. Christophe Pirenne endeavours to examine that field from a m...

  3. Spin polarized low energy electron microscopy of quantum well resonances in Fe films on the Cu-covered W(110) surface.

    Science.gov (United States)

    Wu, Qiang; Altman, M S

    2013-07-01

    Spin polarized low energy electron microscopy has been used to investigate the quantum size effect (QSE) in electron reflectivity from Fe films grown on a pseudomorphic Cu layer on a W(110) surface. Intensity oscillations caused by the QSE as functions of Fe film thickness and incident electron energy identify quantum well resonance conditions in the film. Evaluation of these intensity oscillations using the phase accumulation model provides information on the unoccupied spin polarized band structure in the Fe film above the vacuum level. We also find evidence that the presence of the non-magnetic Cu layer shifts spin polarized quantum well resonances in the Fe layer uniformly downward in energy by 1.1eV compared to Fe/W(110) films without an interface Cu layer, suggesting that the Cu layer gives a small degree of control over the quantum well resonances.

  4. Solar-induced weathering of rocks: integrating instrumental and numerical studies

    Science.gov (United States)

    Hallet, B.; Eppes, M. C.; Mackenzie-Helnwein, P.; Warren, K.; McFadden, L.; Gillespie, A.; Putkonen, J.; Swami, S.; Shi, J.

    2011-12-01

    The contribution of solar-driven thermal cycling to the progressive breakdown of surface rocks on the Earth and other planets is controversial. We introduce a current study of the physical state in boulders that integrates modern instrumental and numerical approaches to quantify the surface temperature, stresses, strains, and microfracture activity in exposed boulders, and to shed light on the processes underlying this form of mechanical weathering. We are monitoring the surface and environmental conditions of two ~30 cm dia. granite boulders (one in North Carolina, one in New Mexico) in the field for ~1 yr each. Each rock is instrumented with 8 thermocouples, 8 strain gauges, a surface moisture sensor and 6 Acoustic Emission (AE) sensors to monitor microfracture activity continuously. These sensors and a full meteorological station, including soil-moisture probes, are combined into a single, remotely accessible system. AE events can be located to within 2.5 cm. We are able 1) to spatially and temporally correlate microcrack growth (AE events) with the rock surface and environmental conditions experienced by the rock, and 2) to validate modeling results. The modeling work addresses two coupled problems: 1) the time-varying thermal regime of rocks exposed to diurnal variations in solar radiation as dictated by latitude, and time of the year, as well as the surface emissivity and thermal properties of the rock and soil, and size and shape of the rock, and 2) the corresponding time-varying stress and strain fields in the rocks using representative elastic properties and realistic rock shape and orientation. AE events tend to occur shortly after sunset (6-9 pm) in the upper portion of the boulder. Most of the events occur in summer and winter months for the NC boulder. The majority occur in bursts of tens to hundreds over periods of a few minutes, and are often associated with environmental factors other than simple diurnal warming and cooling, such as wind gusts, that

  5. Results of hydraulic tests in wells DOE-1, 2, 3, Salt Valley, Grand County, Utah

    Science.gov (United States)

    Rush, F. Eugene; Hart, I.M.; Whitfield, M.S.; Giles, T.F.; D'Epagnier, T. E.

    1980-01-01

    Three exploratory wells were drilled for geological, geophysical, and hydrological purposes in Salt Valley, Grand County, Utah. Cap rock, salt, and interbeds of the Paradox Member of the Hermosa Formation of Middle Pennsylvanian age were penetrated. The observed depth below land surface of the cap rock-salt interface ranges from 163 meters (m) to 191 meters. Approximately the upper 100 meters of cap rock were unsaturated by ground water. Within the saturated part of the cap rock, hydraulic heads generally decrease with depth and southwestward. Ion concentrations generally increase with depth in the saturated cap rock.Hydraulic conductivity of cap rock, as determined from pumping tests, may be on the order of 5 x 10-3 meters per day; as a result, ground-water flow rates in the cap rock are probably very low. A carbon 14 specific activity for cap rock water yielded an uncorrected "age" of greater than 36,000 years. Salt and interbeds have hydraulic conductivities probably less than 1 x 10-4 meters per day.

  6. Systematic study of surface morphology, photoluminescence efficiency, and spin-detection sensitivity in (110)-oriented GaAs/AlGaAs quantum wells

    Science.gov (United States)

    Iba, Satoshi; Saito, Hidekazu; Watanabe, Ken; Ohno, Yuzo; Yuasa, Shinji

    2016-11-01

    We prepared (110)-oriented GaAs/AlGaAs multiple-quantum-well (MQW) samples by molecular beam epitaxy (MBE) under different growth conditions, and conducted systematic measurements of surface morphology, photoluminescence (PL), and spin-detection sensitivity at room temperature. Excellent surface flatness and high PL intensity were observed for the samples grown at temperatures ≥450 °C and As4/Ga flux ratios ≥40. It was found that the PL intensity of (110) MQWs was higher than that of the conventional (100) MQWs grown using the same MBE system. At the same time, we confirmed that the spin-detection sensitivity of (110) MQWs we obtained was an order of magnitude higher than that of the (100) MQWs. These results suggest that the newly developed (110) MQWs indeed have greater advantages than the conventional (100) MQWs for use in emerging spin-optical devices such as spin-controlled lasers.

  7. Photoluminescence of anti-modulation doped near-surface GaAs/AlGaAs single quantum well structures exposed to hydrogen plasma

    CERN Document Server

    Bumaj, Y A; Goldkhan, R; Shtajn, N; Golombek, A; Nakov, V; Cheng, T S

    2002-01-01

    The anti-modulation Si-doped GaAs/AlGaAs structures with near-surface single quantum wells grown by molecular-beam epitaxy were exposed to hydrogen plasma at 260 deg C and investigated by low-temperature photoluminescence, photoluminescence excitation and photoreflectance spectroscopy. After hydrogenation, the quenching of the exciton luminescence for the below AlGaAs band gap excitation due to the increase of electric field in the structure has been observed. The effect is consistent with unpinning of Fermi level from mid gap of nominally undoped (p-type) GaAs cap layer due to passivation of surface states by hydrogen without neutralization of shallow impurities in the epilayers

  8. Observation of the relaxivity and thickness of surface phase in porous rock with the combination of PFG NMR and relaxation measurements

    Institute of Scientific and Technical Information of China (English)

    肖立志; 杜有如; 叶朝辉

    1996-01-01

    Nuclear magnetic resonance (NMR) relaxation of fluids in porous media is affected by the solid-liquid interface. Quantitative determination of the surface relaxivity is significantly important for both investigation and application of relaxation mechanisms in porous media. A method to estimate the surface relaxivity with the combination of relaxation and diffusion measurements is proposed. According to this method, a criterion for testing the current diffusion and relaxation theory for porous media is available.

  9. A Photographic Atlas of Rock Breakdown Features in Geomorphic Environments

    Science.gov (United States)

    Bourke, Mary C. (Editor); Brearley, J. Alexander; Haas, Randall; Viles, Heather A.

    2007-01-01

    A primary goal of geomorphological enquiry is to make genetic associations between process and form. In rock breakdown studies, the links between process, inheritance and lithology are not well constrained. In particular, there is a need to establish an understanding of feature persistence. That is, to determine the extent to which in situ rock breakdown (e.g., aeolian abrasion or salt weathering) masks signatures of earlier geomorphic transport processes (e.g., fluvial transport or crater ejecta). Equally important is the extent to which breakdown during geomorphic transport masks the imprint of past weathering. The use of rock features in this way raises the important question: Can features on the surface of a rock reliably indicate its geomorphic history? This has not been determined for rock surfaces on Earth or other planets. A first step towards constraining the links between process, inheritance, and morphology is to identify pristine features produced by different process regimes. The purpose of this atlas is to provide a comprehensive image collection of breakdown features commonly observed on boulders in different geomorphic environments. The atlas is intended as a tool for planetary geoscientists and their students to assist in identifying features found on rocks on planetary surfaces. In compiling this atlas, we have attempted to include features that have formed 'recently' and where the potential for modification by another geomorphic process is low. However, we acknowledge that this is, in fact, difficult to achieve when selecting rocks in their natural environment. We group breakdown features according to their formative environment and process. In selecting images for inclusion in the atlas we were mindful to cover a wide range of climatic zones. For example, in the weathering chapter, clast features are shown from locations such as the hyper-arid polar desert of Antarctica and the semi-arid canyons of central Australia. This is important as some

  10. Respirable dust measured downwind during rock dust application.

    Science.gov (United States)

    Harris, M L; Organiscak, J; Klima, S; Perera, I E

    2017-05-01

    The Pittsburgh Mining Research Division of the U.S. National Institute for Occupational Safety and Health (NIOSH) conducted underground evaluations in an attempt to quantify respirable rock dust generation when using untreated rock dust and rock dust treated with an anticaking additive. Using personal dust monitors, these evaluations measured respirable rock dust levels arising from a flinger-type application of rock dust on rib and roof surfaces. Rock dust with a majority of the respirable component removed was also applied in NIOSH's Bruceton Experimental Mine using a bantam duster. The respirable dust measurements obtained downwind from both of these tests are presented and discussed. This testing did not measure miners' exposure to respirable coal mine dust under acceptable mining practices, but indicates the need for effective continuous administrative controls to be exercised when rock dusting to minimize the measured amount of rock dust in the sampling device.

  11. Unsupervised feature learning for autonomous rock image classification

    Science.gov (United States)

    Shu, Lei; McIsaac, Kenneth; Osinski, Gordon R.; Francis, Raymond

    2017-09-01

    Autonomous rock image classification can enhance the capability of robots for geological detection and enlarge the scientific returns, both in investigation on Earth and planetary surface exploration on Mars. Since rock textural images are usually inhomogeneous and manually hand-crafting features is not always reliable, we propose an unsupervised feature learning method to autonomously learn the feature representation for rock images. In our tests, rock image classification using the learned features shows that the learned features can outperform manually selected features. Self-taught learning is also proposed to learn the feature representation from a large database of unlabelled rock images of mixed class. The learned features can then be used repeatedly for classification of any subclass. This takes advantage of the large dataset of unlabelled rock images and learns a general feature representation for many kinds of rocks. We show experimental results supporting the feasibility of self-taught learning on rock images.

  12. Late Neoproterozoic basement rocks of Meatiq area, Central Eastern Desert, Egypt: Petrography and remote sensing characterizations

    Science.gov (United States)

    Hassan, Safaa M.; El kazzaz, Yahiya A.; Taha, Maysa M. N.; Mohammad, Abdullah T.

    2017-07-01

    Meatiq dome is one of the mysteries of the basement rocks in Central Eastern Desert (CED) of Egypt. Its mode of formation, and tectonic evolution are still controversial and not fully understood. Satellite remote sensing is a powerful tool for geologic applications, especially in inaccessible regions of the Earth's surface. In this study, three proposed Landsat-8 band ratios (6/2, 6/7, (6/4*4/3)), (6/7, 6/4, 4/2), and (7/5, 7/6, 5/3) are successfully used for detailed geological mapping of the different lithological rock units exposed in Meatiq dome area in the CED. Landsat-8 Principal component (PC) images is also used for refinement the boundaries between the widely-exposed rock units in the study area. Fourteen spectral bands of Advanced Space borne Thermal Emission and Reflection Radiometer (ASTER) data are successfully used to emphasize the distribution of some rock forming minerals (i.e. muscovite, quartz, ferrous oxides, ferrous silicates and hydroxyl-bearing minerals) in the lithological rock units of Meatiq dome area. ASTER muscovite index (B7/B6) and quartz index (B14/B12), ferrous iron index (B5/B3), ferrous silicates index (B5/B4), mafic index (B12/B13) and hydroxyl-bearing minerals index ((B7/B6)*(B4/B6)) discriminate muscovite bearing rocks, Granitoids, and other felsic rocks, amphibolite and other mafic rocks. The proposed image processing methods effectively discriminates between four granitic varieties existed in Meatiq area. They are namely; Abu Ziran, Ariki, Fawakhir and Atalla Plutons. This study reveals that the applied data of ASTER and Landsat-8 enhanced images produced a modified geological map with well emphasized rock units which are verified with field observations, and petrographic study.

  13. Generation of Well-Defined Pairs of Silylamine on Highly Dehydroxylated SBA-15: Application to the Surface Organometallic Chemistry of Zirconium

    KAUST Repository

    Azzi, Joachim

    2012-11-01

    Design of a new well-defined surface organometallic species [O-(=Si–NH)2Zr(IV)Np2] has been obtained by reaction of tetraneopentyl zirconium (ZrNp4) on SBA-15 surface displaying mainly silylamine pairs [O-(=Si–NH2)2]. These surface species have been achieved by an ammonia treatment of a highly dehydroxylated SBA-15 at 1000°C (SBA-151000). This support is known to contain mainly strained reactive siloxane bridges (≡Si-O-Si≡)[1] along with a small amount of isolated plus germinal silanols =Si(OH)2. Chemisorption of ammonia occurs primarily by opening these siloxane bridges[2] to generate silanol/silylamine pairs [O-(=Si–NH2)(=SiOH)] followed by substitution of the remaining silanol. Further treatment using hexamethyldisilazane (HMDS) results in the protection of the isolated remaining silanol groups by formation of ≡Si-O-SiMe3 and =Si(OSiMe3)2 but leaves ≡SiNH2 untouched. After reaction of this functionalized surface with ZrNp4, this latter displays mainly a bi-podal zirconium neopentyl organometallic complex [O-(=Si–NH)2Zr(IV)Np2] which has been fully characterized by diverse methods such as infrared transmission spectroscopy, magic angle spinning solid state nuclear magnetic resonance, surface elemental analysis, small angle X-ray powder diffraction (XRD), nitrogen adsorption and energy filtered transmission electron microscopy (EFTEM). These different characterization tools unambiguously prove that the zirconium organometallic complex reacts mostly with silylamine pairs to give a bi-podal zirconium bis-neopentyl complex, uniformly distributed into the channels of SBA-151000. Therefore this new material opens a new promising research area in Surface Organometallic Chemistry which, so far, was dealing mainly with O containing surface. It is expected that vicinal amine functions may play a very different role as compared with classical inorganic supports. Given the importance in the last decades of N containing ligands in catalysis, one may expect

  14. Corrective Action Investigation Plan for Corrective Action Unit 556: Dry Wells and Surface Release Points Nevada Test Site, Nevada (Draft), Revision 0

    Energy Technology Data Exchange (ETDEWEB)

    Grant Evenson

    2007-02-01

    Corrective Action Unit  (CAU) 556, Dry Wells and Surface Release Points, is located in Areas 6 and 25 of the Nevada Test Site, 65 miles northwest of Las Vegas, Nevada. Corrective Action Unit 556 is comprised of four corrective action sites (CASs) listed below: •06-20-04, National Cementers Dry Well •06-99-09, Birdwell Test Hole •25-60-03, E-MAD Stormwater Discharge and Piping •25-64-01, Vehicle Washdown and Drainage Pit These sites are being investigated because existing information on the nature and extent of potential contamination is insufficient to evaluate and recommend corrective action alternatives. Additional information will be obtained by conducting a corrective action investigation before evaluating corrective action alternatives and selecting the appropriate corrective action for each CAS. The results of the field investigation will support a defensible evaluation of viable corrective action alternatives that will be presented in the Corrective Action Decision Document.

  15. Contrasting responses of Central Asian rock glaciers to global warming

    OpenAIRE

    Annina Sorg; Andreas Kääb; Andrea Roesch; Christof Bigler; Markus Stoffel

    2015-01-01

    While the responses of Tien Shan glaciers – and glaciers elsewhere – to climatic changes are becoming increasingly well understood, this is less the case for permafrost in general and for rock glaciers in particular. We use a novel approach to describe the climate sensitivity of rock glaciers and to reconstruct periods of high and low rock glacier activity in the Tien Shan since 1895. Using more than 1500 growth anomalies from 280 trees growing on rock glacier bodies, repeat aerial photograph...

  16. Synthesis of well-defined structurally silica-nonlinear polymer core-shell nanoparticles via the surface-initiated atom transfer radical polymerization

    Science.gov (United States)

    Chen, Jiucun; Hu, Min; Zhu, Wendong; Li, Yaping

    2011-05-01

    We report on the synthesis of the well-defined structurally silica-nonlinear polymer core-shell nanoparticles via the surface-initiated atom transfer radical polymerization. At first, 3-(2-bromoisobutyramido)propyl(triethoxy)-silane (the ATRP initiator) was prepared by the reaction of 3-aminopropyltriethoxysilane with 2-bromoisobutyryl bromide. The ATRP initiator was covalently attached onto the nanosilica surface. The subsequent ATRP of HEMA from the initiator-attached SiO 2 surface was carried out in order to afforded functional nanoparticles bearing a hydroxyl moiety at the chain end, SiO 2-g-PHEMA-Br. The esterification reaction of pendent hydroxyl moieties of PHEMA segment with 2-bromoisobutyryl bromide afforded the SiO 2-based multifunctional initiator, SiO 2-g-PHEMA(-Br)-Br, bearing one bromine moiety on each monomer repeating unit within the PHEMA segment. Finally, the synthesis of SiO 2-g-PHEMA(-g-PSt)-b-PSt was accomplished by the ATRP of St monomer using SiO 2-g-PHEMA(-Br)-Br as multifunctional initiator. These organic/inorganic hybrid materials have been extensively characterized by FT-IR, XPS, TG, and TEM.

  17. Spatially well-defined binary brushes of poly(ethylene glycol)s for micropatterning of active proteins on anti-fouling surfaces.

    Science.gov (United States)

    Xu, F J; Li, H Z; Li, J; Teo, Y H Eric; Zhu, C X; Kang, E T; Neoh, K G

    2008-12-01

    We report a novel method for micropatterning of active proteins on anti-fouling surfaces via spatially well-defined and dense binary poly(ethylene glycol)s (PEGs) brushes with controllable protein-docking sites. Binary brushes of poly(poly(ethylene glycol) methacrylate-co-poly(ethylene glycol)methyl ether methacrylate), or P(PEGMA-co-PEGMEMA), and poly(poly(ethylene glycol)methyl ether methacrylate), or P(PEGMEMA), were prepared via consecutive surface-initiated atom transfer radical polymerizations (SI-ATRPs) from a resist-micropatterned Si(100) wafer surface. The terminal hydroxyl groups on the side chains of PEGMA units in the P(PEGMA-co-PEGMEMA) microdomains were activated directly by 1,1'-carbonyldiimidazole (CDI) for the covalent coupling of human immunoglobulin (IgG) (as a model active protein). The resulting IgG-coupled PEG microdomains interact only and specifically with target anti-IgG, while the other PEG microregions effectively prevent specific and non-specific protein fouling. When extended to other active biomolecules, microarrays for specific and non-specific analyte interactions with a high signal-to-noise ratio could be readily tailored.

  18. ROCKS&MINERALS; DETERMINATION AND ANALYSIS

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    20151619 Bao Xue(Gem and Jewelry Institute of Beijing,Ministry of Land and Resources,Beijing100013,China);Lu Taijin Application of Surface Contact Angle and Surface Tension Measurements in the Identification of Gem Materials(Rock and Mineral Analysis,ISSN0254

  19. Distinct roles for ROCK1 and ROCK2 in the regulation of keratinocyte differentiation.

    Directory of Open Access Journals (Sweden)

    Frances E Lock

    Full Text Available BACKGROUND: The human epidermis is comprised of several layers of specialized epithelial cells called keratinocytes. Normal homoeostasis of the epidermis requires that the balance between keratinocyte proliferation and terminal differentiation be tightly regulated. The mammalian serine/threonine kinases (ROCK1 and ROCK2 are well-characterised downstream effectors of the small GTPase RhoA. We have previously demonstrated that the RhoA/ROCK signalling pathway plays an important role in regulation of human keratinocyte proliferation and terminal differentiation. In this paper we addressed the question of which ROCK isoform was involved in regulation of keratinocyte differentiation. METHODOLOGY AND PRINCIPAL FINDINGS: We used RNAi to specifically knockdown ROCK1 or ROCK2 expression in cultured human keratinocytes. ROCK1 depletion results in decreased keratinocyte adhesion to fibronectin and an increase in terminal differentiation. Conversely, ROCK2 depletion results in increased keratinocyte adhesion to fibronectin and inhibits terminal differentiation. CONCLUSION: These data suggest that ROCK1 and ROCK2 play distinct roles in regulating keratinocyte adhesion and terminal differentiation.

  20. Monitoring rock glacier dynamics and ground temperatures in the semiarid Andes (Chile, 30°S)

    Science.gov (United States)

    Brenning, Alexander; Azócar, Guillermo F.; Bodin, Xavier

    2013-04-01

    Rock glaciers and mountain permafrost are widespread in the high semiarid Andes of Chile, where they concentrate greater amounts of ice than glaciers. Rock glaciers are of particular interest because in some cases the permafrost they contain might be in a degrading in response to climatic warming. This could result in increased dynamics and even to destabilization, which has been observed on some rock glaciers in the studied area. Displacement rates and active-layer temperatures of two rock glaciers as well as ground surface temperatures of the periglacial environment in the upper Elqui valley have been monitored since summer 2009/10 with funding from the Chilean Dirección General de Aguas. Differential GPS measurements of 115 points on the surface of two rock glaciers since April 2010 showed horizontal displacements of up to 1.3 m/a on the Llano de las Liebres rock glacier and up to 1.2 m/a on the Tapado rock glacier. General velocity patterns are consistent with the morphological evidence of activity (e.g., front slopes, looseness of debris) and for the Tapado complex, a clearly distinct activity from the debris-covered glacier was observed. Temperature measurements in four boreholes indicate active-layer depths of about 2.5 m at the highest locations on the Tapado rock glacier (~4400 m a.s.l.) and about 8 m near the front of the Llano rock glacier (3786 m a.s.l.). Spatial patterns of mean ground surface temperature (MGST) were analyzed with regards to influences of elevation, potential incoming solar radiation, location on ice-debris landforms (rock and debris-covered glaciers), and snow cover duration using linear mixed-effects models. While accounting for the other variables, sites with long-lasting snow patches had ~0.4°C lower MGST, and ice-debris landforms had ~0.4-0.6°C lower MGST than general debris surfaces, highlighting important local modifications to the general topographic variation of ground thermal conditions.

  1. In search for coastal amplification of rock weathering in polar climates - pilot Schmidt hammer rock tests surveys from sheltered fjords of Svalbard and tsunami-affected coasts of Western Greenland.

    Science.gov (United States)

    Strzelecki, Matt

    2014-05-01

    Recent decade has seen the major advance in Arctic coastal geomorphology due to research progress along ice-rich permafrost coastlines of Siberia, Alaska and NW Canada. On the contrary little attention was paid to Arctic rocky coastlines and their response to the reduction of sea ice cover and increased number of storms reaching Arctic region. In this paper I present results from a pilot survey of rock resistance using Schmidt Hammer Rock Tests across rocky cliffs and shore platforms developed in: - sheltered bays of Billefjorden, Svalbard characterised by prolonged sea-ice conditions and very limited operation of wave and tidal action - Vaigat Strait and Isfjorden in W Greenland influenced by landslide-triggered tsunamis and waves induced by ice-berg roll events. The aim of a pilot study was to test the hypothesized coastal impact on the rate of rock weathering in polar climates. To do so I characterise the changes in the rock resistance on the following coastal landforms: - modern and uplifted wave-washed abrasion platforms- focusing on a relation between the degree of rock surface weathering and the distance from the shoreline as well as thickness of sediment cover on shore platform surface - modern and uplifted rocky cliffs - focusing on a relation between the degree of rock surface weathering and the distance from the shoreline as well as difference in height above the sea level and relation to rock lithology. The results present another line of argument supporting intensification of rock weathering processes in the Arctic coastal zone. This work is a contribution to the National Science Centre in Poland research project no. 2011/01/B/ST10/01553.

  2. Facile preparation of glycoprotein-imprinted 96-well microplates for enzyme-linked immunosorbent assay by boronate affinity-based oriented surface imprinting.

    Science.gov (United States)

    Bi, Xiaodong; Liu, Zhen

    2014-01-01

    Molecularly imprinted polymers (MIPs), as inexpensive and stable substitutes of antibodies, have shown great promise in immunoassays. Glycoproteins are of significant diagnostic value. To facilitate the application of MIPs in clinical diagnostics, a general and facile imprinting method toward glycoproteins oriented for an enzyme-linked immunosorbent assay (ELISA) in the form of a 96-well microplate is essential but has not been fully explored yet. In this study, a new method called boronate affinity-based oriented surface imprinting was proposed for facile preparation of glycoprotein-imprinted microplates. A template glycoprotein was first immobilized by a boronic acid-modified microplate through boronate affinity binding, and then, a thin layer of polyaniline was formed to cover the microplate surface via in-water self-copolymerization. After the template was removed by an acidic solution, 3D cavities that can rebind the template were fabricated on the microplate surface. Using horseradish peroxidase (HRP) as a model target, the effects of imprinting conditions as well as the properties and performance of the prepared MIPs were investigated. α-Fetoprotein (AFP)-imprinted microplate was then prepared, and thereby, a MIP-based ELISA method was established. The prepared MIPs exhibited several highly favorable features, including excellent specificity, widely applicable binding pH, superb tolerance for interference, high binding strength, fast equilibrium kinetics, and reusability. The MIP-based ELISA method was finally applied to the analysis of AFP in human serum. The result was in good agreement with that by radioimmunoassay, showing a promising prospect of the proposed method in clinical diagnostics.

  3. A study of rock bolting failure modes

    Institute of Scientific and Technical Information of China (English)

    Cao Chen; Jan Nemcik; Ren Ting; Naj Aziz

    2013-01-01

    Rock bolting has advanced rapidly during the past 4 decades due to a better understanding of load transfer mechanisms and advances made in the bolt system technology.Bolts are used as permanent and temporary support systems in tunnelling and mining operations.A review of has indicated that three systems of reinforcement devices have evolved as part of rock bolt and ground anchor while the rock is not generally thought of as being a component of the reinforcement system.A classification of rock bolting reinforcement systems is presented,followed by the fundamental theory of the load transfer mechanism.The failure mode of two phases of rock bolting system is formularised.The failure modes of cable bolting are discussed using a bond strength model as well as an iterative method.Finally,the interfacial shear stress model for ribbed bar is introduced and a closed form solution is obtained using a tri-line stress strain relationship.

  4. Evidence of Ancient Blisters in Rocks

    Science.gov (United States)

    2004-01-01

    This image from the panoramic camera on the Mars Exploration Rover Spirit shows scoriaceous rocks (rocks containing holes or cavities) on the ground, as well as a transition from rocky terrain (foreground) to smoother terrain (background). Spirit is heading toward the smoother terrain on its way to the 'Columbia Hills.' The holes in some of the rocks may have resulted from 'blisters' formed by water vapor as it escaped lava. This indicates that the rocks were chilled atop an ancient lava flow. Porous rocks such as these, now appearing in abundance, have not been seen since early in the mission. Scientists believe they may have been covered by crater ejecta. This image was taken on sol 110 (April 24, 2004) at a region dubbed 'site 35.'

  5. Robotic Instrument for Grinding Rocks Into Thin Sections (GRITS)

    Science.gov (United States)

    Paulsen, Gale; Zacny, Kris; Dreyer, Christopher B.; Szucs, Attila; Szczesiak, Matt; Santoro, Chris; Craft, Jack; Hedlund, Magnus; Skok, John

    2013-06-01

    We have developed a rock grinding and polishing mechanism for in situ planetary exploration based on abrasive disks, called Grinding Rocks Into Thin Sections (GRITS). Performance characteristics and design considerations of GRITS are presented. GRITS was developed as part of a broader effort to develop an in situ automated rock thin section (ISARTS) instrument. The objective of IS-ARTS was to develop an instrument capable of producing petrographic rock thin sections on a planetary science spacecraft. GRITS may also be useful to other planetary science missions with in situ instruments in which rock surface preparation are necessary.

  6. Assessment of abrasiveness for research of rock cutting

    Directory of Open Access Journals (Sweden)

    Milan Labaš

    2012-12-01

    Full Text Available Rock abrasiveness is ability of rock to wear down the working tool during the mutual interaction between the working indentorand the rock in the mechanical rock cutting process. The cutting indentor is worn down during the interaction, which changes itsgeometric dimensions causing the enlargement of a contact area between the tool and the rock surface. The changes in these dimensionsconsequently alter the rate of advance of the drilling machine and the specific cutting energy. We have determined the abrasivenessaccording to the norm ON 44 1121 (1982 on the testing device constructed at the Institute of Geotechnics SAS.

  7. Rock avalanches: significance and progress (Invited)

    Science.gov (United States)

    Davies, T. R.

    2013-12-01

    1. The probability distribution of landslide volumes follows a power-law indicating that large rock avalanches dominate the terrestrial sediment supply from mountains, and that their source area morphologies dominate mountain topography. 2. Large rock slope failures (~ 106 m3 or greater) often mobilise into rock avalanches, which can travel extraordinarily long distances with devastating effect. This hypermobility has been the subject of many investigations; we have demonstrated that it can be explained quantitatively and accurately by considering the energetics of the intense rock fragmentation that always occurs during motion of a large rock mass. 3. Study of rock avalanche debris psd shows that the energy used in creating new rock surface area during fragmentation is not lost to surface energy, but is recycled generating a high-frequency elastic energy field that reduces the frictional resistance to motion during runout. 4. Rock avalanches that deposit on glaciers can eventually form large terminal moraines that have no connection with any climatic event; unless these are identified as rock-avalanche-influenced they can confuse palaeoclimatic inferences drawn from moraine ages. Rock-avalanche-derived fines, however, can be identified in moraine debris up to ten thousand years old by the characteristic micron-scale agglomerates that form during intense fragmentation, and which are absent from purely climatically-induced moraines; there is thus a strong case for re-examining existing palaeoclimatic databases to eliminate potentially rock-avalanche-influenced moraine ages. 5. Rock avalanches (especially coseismic ones) are a serious hazard, being very destructive in their own right; they also block river valleys, forming landslide dams and potentially devastating dambreak floods, and subsequent severe decade-scale aggradation of downstream fans and floodplains. Rock avalanches falling into lakes or fiords can cause catastrophic tsunami that pose a serious risk to

  8. Quantitative Morphologic Analysis of Boulder Shape and Surface Texture to Infer Environmental History: A Case Study of Rock Breakdown at the Ephrata Fan, Channeled Scabland, Washington

    Science.gov (United States)

    Ehlmann, Bethany L.; Viles, Heather A.; Bourke, Mary C.

    2008-01-01

    Boulder morphology reflects both lithology and climate and is dictated by the combined effects of erosion, transport, and weathering. At present, morphologic information at the boulder scale is underutilized as a recorder of environmental processes, partly because of the lack of a systematic quantitative parameter set for reporting and comparing data sets. We develop such a parameter set, incorporating a range of measures of boulder form and surface texture. We use standard shape metrics measured in the field and fractal and morphometric classification methods borrowed from landscape analysis and applied to laser-scanned molds. The parameter set was pilot tested on three populations of basalt boulders with distinct breakdown histories in the Channeled Scabland, Washington: (1) basalt outcrop talus; (2) flood-transported boulders recently excavated from a quarry; and (3) flood-transported boulders, extensively weathered in situ on the Ephrata Fan surface. Size and shape data were found to distinguish between flood-transported and untransported boulders. Size and edge angles (approximately 120 degrees) of flood-transported boulders suggest removal by preferential fracturing along preexisting columnar joints, and curvature data indicate rounding relative to outcrop boulders. Surface textural data show that boulders which have been exposed at the surface are significantly rougher than those buried by fan sediments. Past signatures diagnostic of flood transport still persist on surface boulders, despite ongoing overprinting by processes in the present breakdown environment through roughening and fracturing in situ. Further use of this quantitative boulder parameter set at other terrestrial and planetary sites will aid in cataloging and understanding morphologic signatures of environmental processes.

  9. Quantitative Morphologic Analysis of Boulder Shape and Surface Texture to Infer Environmental History: A Case Study of Rock Breakdown at the Ephrata Fan, Channeled Scabland, Washington

    Science.gov (United States)

    Ehlmann, Bethany L.; Viles, Heather A.; Bourke, Mary C.

    2008-01-01

    Boulder morphology reflects both lithology and climate and is dictated by the combined effects of erosion, transport, and weathering. At present, morphologic information at the boulder scale is underutilized as a recorder of environmental processes, partly because of the lack of a systematic quantitative parameter set for reporting and comparing data sets. We develop such a parameter set, incorporating a range of measures of boulder form and surface texture. We use standard shape metrics measured in the field and fractal and morphometric classification methods borrowed from landscape analysis and applied to laser-scanned molds. The parameter set was pilot tested on three populations of basalt boulders with distinct breakdown histories in the Channeled Scabland, Washington: (1) basalt outcrop talus; (2) flood-transported boulders recently excavated from a quarry; and (3) flood-transported boulders, extensively weathered in situ on the Ephrata Fan surface. Size and shape data were found to distinguish between flood-transported and untransported boulders. Size and edge angles (approximately 120 degrees) of flood-transported boulders suggest removal by preferential fracturing along preexisting columnar joints, and curvature data indicate rounding relative to outcrop boulders. Surface textural data show that boulders which have been exposed at the surface are significantly rougher than those buried by fan sediments. Past signatures diagnostic of flood transport still persist on surface boulders, despite ongoing overprinting by processes in the present breakdown environment through roughening and fracturing in situ. Further use of this quantitative boulder parameter set at other terrestrial and planetary sites will aid in cataloging and understanding morphologic signatures of environmental processes.

  10. Statistical pattern recognition for rock joint images

    Science.gov (United States)

    Wang, Weixing; Bin, Cui

    2005-10-01

    As a cooperation project between Sweden and China, we sampled a number of rock specimens for analyze rock fracture network by optical image technique. The samples are resin injected, in which way; opened fractures can be seen clearly by means of UV (Ultraviolet) light illumination. In the study period, Recognition of rock fractures is crucial in many rock engineering applications. In order to successfully applying automatic image processing techniques for the problem of automatic (or semi-automatic) rock fracture detection and description, the key (and hardest task) is the automatic detection of fractures robustly in images. When statistical pattern recognition is used to segment a rock joint color image, features of different samples can be learned first, then, each pixel of the image is classified by these features. As the testing result showing, an attribute rock fracture image is segmented satisfactorily by using this way. The method can be widely used for other complicated images too. In this paper, Kernel Fisher discrimination (KFD) is employed to construct a statistical pattern recognition classifier. KFD can transform nonlinear discrimination in an attribute space with high dimension, into linear discrimination in a feature space with low dimension. While one needs not know the detailed mapping form from attribute space to feature space in the process of transformation. It is proved that this method performs well by segmenting complicated rock joint color images.

  11. High field electron paramagnetic resonance spectroscopy under ultrahigh vacuum conditions—A multipurpose machine to study paramagnetic species on well defined single crystal surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Rocker, J.; Cornu, D.; Kieseritzky, E.; Hänsel-Ziegler, W.; Freund, H.-J. [Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin (Germany); Seiler, A. [Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin (Germany); Laboratorium für Applikationen der Synchrotronstrahlung, KIT Campus Süd, Kaiserstr. 12, 76131 Karlsruhe (Germany); Bondarchuk, O. [Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin (Germany); CIC energiGUNE, Parque Tecnologico, C/Albert Einstein 48, CP 01510 Minano (Alava) (Spain); Risse, T., E-mail: risse@chemie.fu-berlin.de [Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin (Germany); Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin (Germany)

    2014-08-01

    A new ultrahigh vacuum (UHV) electron paramagnetic resonance (EPR) spectrometer operating at 94 GHz to investigate paramagnetic centers on single crystal surfaces is described. It is particularly designed to study paramagnetic centers on well-defined model catalysts using epitaxial thin oxide films grown on metal single crystals. The EPR setup is based on a commercial Bruker E600 spectrometer, which is adapted to ultrahigh vacuum conditions using a home made Fabry Perot resonator. The key idea of the resonator is to use the planar metal single crystal required to grow the single crystalline oxide films as one of the mirrors of the resonator. EPR spectroscopy is solely sensitive to paramagnetic species, which are typically minority species in such a system. Hence, additional experimental characterization tools are required to allow for a comprehensive investigation of the surface. The apparatus includes a preparation chamber hosting equipment, which is required to prepare supported model catalysts. In addition, surface characterization tools such as low energy electron diffraction (LEED)/Auger spectroscopy, temperature programmed desorption (TPD), and infrared reflection absorption spectroscopy (IRAS) are available to characterize the surfaces. A second chamber used to perform EPR spectroscopy at 94 GHz has a room temperature scanning tunneling microscope attached to it, which allows for real space structural characterization. The heart of the UHV adaptation of the EPR experiment is the sealing of the Fabry-Perot resonator against atmosphere. To this end it is possible to use a thin sapphire window glued to the backside of the coupling orifice of the Fabry Perot resonator. With the help of a variety of stabilization measures reducing vibrations as well as thermal drift it is possible to accumulate data for a time span, which is for low temperature measurements only limited by the amount of liquid helium. Test measurements show that the system can detect paramagnetic

  12. Soft rocks in Argentina

    Institute of Scientific and Technical Information of China (English)

    Giambastiani; Mauricio

    2014-01-01

    Soft rocks are a still fairly unexplored chapter in rock mechanics. Within this category are the clastic sedimentary rocks and pyroclastic volcanic rocks, of low to moderate lithification (consolidation, cemen-tation, new formed minerals), chemical sedimentary rocks and metamorphic rocks formed by minerals with Mohs hardness less than 3.5, such as limestone, gypsum, halite, sylvite, between the first and phyllites, graphitic schist, chloritic shale, talc, etc., among the latter. They also include any type of rock that suffered alteration processes (hydrothermal or weathering). In Argentina the study of low-strength rocks has not received much attention despite having extensive outcrops in the Andes and great impact in the design criteria. Correlation between geomechanical properties (UCS, deformability) to physical index (porosity, density, etc.) has shown promising results to be better studied. There are many studies and engineering projects in Argentina in soft rock geological environments, some cited in the text (Chihuído dam, N. Kirchner dam, J. Cepernic Dam, etc.) and others such as International Tunnel in the Province of Mendoza (Corredor Bioceánico), which will require the valuable contribution from rock mechanics. The lack of consistency between some of the physical and mechanical parameters explored from studies in the country may be due to an insufficient amount of information and/or non-standardization of criteria for testing materials. It is understood that more and better academic and professional efforts in improv-ing techniques will result in benefits to the better understanding of the geomechanics of weak rocks.

  13. Bolt-grouting combined support technology in deep soft rock roadway

    Institute of Scientific and Technical Information of China (English)

    Chen Yanlong; Meng Qingbin; Xu Guang; Wu Haoshuai; Zhang Guimin

    2016-01-01

    Analyzing the mineral composition, mechanical properties and ground stress testing in surrounding rock, the study investigated the failure mechanism of deep soft rock roadway with high stress. The bolt-grouting combined support system was proposed to prevent such failures. By means of FLAC3D numer-ical simulation and similar material simulation, the feasibility of the support design and the effectiveness of support parameters were discussed. According to the monitoring the surface and deep displacement in surrounding rock as well as bolt axial load, this paper analyzed the deformation of surrounding rock and the stress condition of the support structure. The monitor results were used to optimize the proposed support scheme. The results of field monitors demonstrate that the bolt-grouting combined support tech-nology could improve the surround rock strength and bearing capacity of support structure, which con-trolled the great deformation failure and rheological property effectively in deep soft rock roadway with high stress. As a result, the long term stability and safety are guaranteed.

  14. Agricultural Drainage Well Intakes

    Data.gov (United States)

    Iowa State University GIS Support and Research Facility — Locations of surface intakes for registered agriculture drainage wells according to the database maintained by IDALS. Surface intakes were located from their...

  15. Comparative investigation of predrilled liner and barefoot completion of horizontal wells in Stassfurt carbonate rock; Vergleich von Predrilled Liner-/Barefoot-Komplettierungen in horizontalen Bohrungen im Stassfurt-Karbonat

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, M.W. [Mobil Erdgas-Erdoel GmbH, Celle (Germany)

    1999-07-01

    When selecting the completion type of a horizontal well, all relevant aspects for production and reservoir engineering for safe and optimized long term production have to be considered. Mainly in sour gas wells with the need of corrosionresistent and expensive alloys, the technical/economic requirements for running a liner in the horizontal section are often be discussed. This paper compares the preinvestment of a 'Predrilled liner' with the costs of downhole operations which may become necessary in a 'Barefoot Completion'. These calculated 'Risk Savings' - as a function of the horizontal length - lead to a Break-Even-Point which is supposed to assist the decision of running a liner in sour gas wells or not. (orig.) [German] Bei der Auswahl der Komplettierung einer Horizontalbohrung ist es erforderlich, alle produktions- und lagerstaettentechnischen Aspekte einfliessen zu lassen, um langfristig eine sichere und optimierte Foerderung zu gewaehrleisten. Gerade in Sauergasbohrungen mit den korrosionsresistenten, sehr teuren Werkstoffen, wird die technisch/wirtschaftliche Notwendigkeit einer Verrohrung des horizontalen Aufschlusses haeufig diskutiert. In diesem Beitrag werden die Investition fuer einen 'Predrilled Liner' und Folgekosten von moeglichen Untertage-Arbeiten in einer 'Barefoot - Completion' in Sauergasbohrungen gegenuebergestellt und bewertet. Aus den errechneten 'Risked Savings' wird in Abhaengigkeit der Laenge des Traegeraufschlusses ein Break-Even-Point ermittelt, der eine Entscheidungshilfe fuer eine Traegerverrohrung im Stassfurtkarbonat darstellen soll. (orig.)

  16. Determination of concentrations and isotopic ratio of uranium in groundwaters drawn from two deep wells drilled in granitic rocks belonging to Itu intrusive suite; Determinacao das concentracoes e razoes isotopicas de uranio em aguas subterraneas extraidas de pocos perfurados em rochas da suite intrusiva de Itu (SP)

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Francisca de; Reyes, Erika; Marques, Leila Soares [Sao Paulo Univ., SP (Brazil). Inst. de Astronomia, Geofisica e Ciencias Atmosfericas. Dept. de Geofisica]. E-mail: francisca@iag.usp.br; erika@iag.usp.br; leila@iag.usp.br

    2005-07-01

    This paper presents the first results obtained in the determination of dissolved uranium concentrations and ({sup 234}U/{sup 238}U) activity ratios of groundwaters drawn from two deep wells drilled in granitic rocks belonging to Itu Intrusive Suite, which is located at eastern Sao Paulo State. One of the wells, whose groundwaters have been analyzed, is located in Salto Town, while the other one is located in Itu Town. The groundwater sampling is monthly and begun on September, 2004, in order to investigate possible sazonal variations. The alpha spectrometry technique, associated with isotopic dilution method, has been used for these determinations. The data obtained up to now show that the groundwaters from Salto present uranium concentrations significantly lower ((0.098 {+-} 0.007) - (0.17 {+-} 0.01) ng/g) than those from Itu ((0.22 {+-} 0.02) - (0.31 {+-} 0.02) ng/g). The {sup 234}U and {sup 238}U isotopes of the investigated groundwaters from both wells are in radioactive disequilibrium, with ({sup 234}U/{sup 238}U) activity ratios systematically higher than unity. Although the groundwaters from Salto well are characterized by low {sup 234}U and {sup 238}U specific activities they present higher ({sup 234}U/{sup 238}U) activity ratios than those from Itu. The observed differences on the behavior of uranium concentrations and ({sup 234}U/{sup 238}U) activity ratios in the groundwaters from the two wells are very probably due to the large variety of granitic rocks from Itu Intrusive Suite, which are characterized by distinct uranium abundances. (author)

  17. Rock Cycle Roulette.

    Science.gov (United States)

    Schmidt, Stan M.; Palmer, Courtney

    2000-01-01

    Introduces an activity on the rock cycle. Sets 11 stages representing the transitions of an earth material in the rock cycle. Builds six-sided die for each station, and students move to the stations depending on the rolling side of the die. Evaluates students by discussing several questions in the classroom. Provides instructional information for…

  18. Rock fracture image acquisition with both visible and ultraviolet illuminations

    Science.gov (United States)

    Wang, Weixing; Hakami, Eva

    2006-02-01

    Swedish Nuclear Fuel and Waste Management Company (SKB) have identified the need for a better understanding of radionuclide transport and retention processes in fractured rock since 1994. In the study, the first hard problem is to obtain rock fracture images of a good quality, since rock surface is very rough, and composed of complicated and multiple fractures, as a result, image acquisition is the first important. As a cooperation project between Sweden and China, we sampled a number of rock specimens for analyzing rock fracture network by visible and ultraviolet image technique, in the field. The samples are resin injected, in which way; opened fractures can be seen clearly by means of UV light illumination, and the rock surface information can be obtained by using visible optical illumination. We used different digital cameras and microscope to take images by two illuminations. From the same samples; we found that UV illumination image gives the clear information of fracture opening or closing, and the visible optical illumination gives the information of the rock surface (e.g. filling materials inside of fractures). By applying this technique, the minimum width of rock fracture 0.01 mm can be analyzed. This paper presents: (1) Rock fracture image acquiring techniques; (2) Rock fracture image acquisition by using UV light illumination and visible optical illumination; and (3) Conclusions. The studied method can be used both in the field and a laboratory.

  19. Consequence assessment of large rock slope failures in Norway

    Science.gov (United States)

    Oppikofer, Thierry; Hermanns, Reginald L.; Horton, Pascal; Sandøy, Gro; Roberts, Nicholas J.; Jaboyedoff, Michel; Böhme, Martina; Yugsi Molina, Freddy X.

    2014-05-01

    Steep glacially carved valleys and fjords in Norway are prone to many landslide types, including large rockslides, rockfalls, and debris flows. Large rockslides and their secondary effects (rockslide-triggered displacement waves, inundation behind landslide dams and outburst floods from failure of landslide dams) pose a significant hazard to the population living in the valleys and along the fjords shoreline. The Geological Survey of Norway performs systematic mapping of unstable rock slopes in Norway and has detected more than 230 unstable slopes with significant postglacial deformation. This large number necessitates prioritisation of follow-up activities, such as more detailed investigations, periodic displacement measurements, continuous monitoring and early-warning systems. Prioritisation is achieved through a hazard and risk classification system, which has been developed by a panel of international and Norwegian experts (www.ngu.no/en-gb/hm/Publications/Reports/2012/2012-029). The risk classification system combines a qualitative hazard assessment with a consequences assessment focusing on potential life losses. The hazard assessment is based on a series of nine geomorphological, engineering geological and structural criteria, as well as displacement rates, past events and other signs of activity. We present a method for consequence assessment comprising four main steps: 1. computation of the volume of the unstable rock slope; 2. run-out assessment based on the volume-dependent angle of reach (Fahrböschung) or detailed numerical run-out modelling; 3. assessment of possible displacement wave propagation and run-up based on empirical relations or modelling in 2D or 3D; and 4. estimation of the number of persons exposed to rock avalanches or displacement waves. Volume computation of an unstable rock slope is based on the sloping local base level technique, which uses a digital elevation model to create a second-order curved surface between the mapped extent of

  20. Hierarchical micron-sized mesoporous/macroporous graphene with well-tuned surface oxygen chemistry for high capacity and cycling stability Li-O2 battery.

    Science.gov (United States)

    Zhou, Wei; Zhang, Hongzhang; Nie, Hongjiao; Ma, Yiwen; Zhang, Yining; Zhang, Huamin

    2015-02-11

    Nonaqueous Li-O2 battery is recognized as one of the most promising energy storage devices for electric vehicles due to its super-high energy density. At present, carbon or catalyst-supporting carbon materials are widely used for cathode materials of Li-O2 battery. However, the unique electrode reaction and complex side reactions lead to numerous hurdles that have to be overcome. The pore blocking caused by the solid products and the byproducts generated from the side reactions severely limit the capacity performance and cycling stability. Thus, there is a great need to develop carbon materials with optimized pore structure and tunable surface chemistry to meet the special requirement of Li-O2 battery. Here, we propose a strategy of vacuum-promoted thermal expansion to fabricate one micron-sized graphene matrix with a hierarchical meso-/macroporous structure, combining with a following deoxygenation treatment to adjust the surface chemistry by reducing the amount of oxygen and selectively removing partial unstable groups. The as-made graphene demonstrates dramatically tailored pore characteristics and a well-tuned surface chemical environment. When applied in Li-O2 battery as cathode, it exhibits an outstanding capacity up to 19 800 mA h g(-1) and is capable of enduring over 50 cycles with a curtaining capacity of 1000 mA h g(-1) at a current density of 1000 mA g(-1). This will provide a novel pathway for the design of cathodes for Li-O2 battery.

  1. Low grade metamorphism of mafic rocks

    Science.gov (United States)

    Schiffman, Peter

    1995-07-01

    Through most of this past century, metamorphic petrologists in the United States have paid their greatest attention to high grade rocks, especially those which constitute the core zones of exhumed, mountain belts. The pioneering studies of the 50's through the 80's, those which applied the principles of thermodynamics to metamorphic rocks, focused almost exclusively on high temperature systems, for which equilibrium processes could be demonstrated. By the 1980's, metamorphic petrologists had developed the methodologies for deciphering the thermal and baric histories of mountain belts through the study of high grade rocks. Of course, low grade metamorphic rocks - here defined as those which form at pressures and temperatures up to and including the greenschist facies - had been well known and described as well, initially through the efforts of Alpine and Circum-Pacific geologists who recognized that they constituted an integral and contiguous portion of mountain belts, and that they underlay large portions of accreted terranes, many of oceanic origins. But until the mid 80's, much of the effort in studying low grade rocks - for a comprehensive review of the literature to that point see Frey (1987) - had been concentrated on mudstones, volcanoclastic rocks, and associated lithologies common to continental mountain belts and arcs. In the mid 80's, results of the Deep Sea Drilling Project (DSDP) rather dramatically mitigated a shift in the study of low grade metamorphic rocks.

  2. InGaN multiple-quantum-well epifilms on GaN-sillicon substrates for microcavities and surface-emitting lasers

    Energy Technology Data Exchange (ETDEWEB)

    Lee, June Key [Chonnam National University, Gwangju (Korea, Republic of); Cho, Hoon; Kim, Bok Hee; Park, Si Hyun [Chosun University, Gwangju (Korea, Republic of); Gu, Erdan; Watson, Ian; Dawson, Martin [University of Strathclyde, Wolfson Centre, Glasgow (United Kingdom)

    2006-07-15

    We report the processing of InGaN/GaN epifilms on GaN-silicon substrates. High-quality InGaN/GaN multi-quantum wells (MQWs) were grown on GaN-silicon substrates, and their membranes were successfully fabricated using a selective wet etching of silicon followed by a dry etching of the AlGaN buffer layer. With atomic force microscope (AFM) measurements and photoluminescence (PL) measurements, we investigated the physical and the optical properties of the InGaN/GaN MQWs membranes. On the InGaN/GaN MQW membranes, dielectric distributed Bragg reflector (DBRs) were successfully deposited, which give, new possibilities for use in GaN microcavity and surface-emitting laser fabrication.

  3. Thin-film solar cells with InGaAs/GaAsP multiple quantum wells and a rear surface etched with light trapping micro-hole array

    Science.gov (United States)

    Watanabe, Kentaroh; Inoue, Tomoyuki; Sodabanlu, Hassanet; Sugiyama, Masakazu; Nakano, Yoshiaki

    2015-08-01

    A light trapping effect in GaAs p-i-n solar cells with InGaAs/GaAsP multiple quantum wells (MQWs) in the i-layer was demonstrated by applying a light scattering texture to the rear surface of the cell. A thin-film MQW solar cell was successfully fabricated by metal organic vapor phase epitaxy (MOVPE) to grow an inverted n-i-p photovoltaic (PV) structure; this structure was then transferred to a Si support substrate to prevent optical loss due to free carrier absorption. For the light scattering texture, the use of both the wet-etched micro-hole arrayed SiO2 dielectric layer on the rear surface of the cell and the secondarily etched micro hole array on the GaAs layer was attempted. On the SiO2 layer, the micro hole array pattern was obtained by the radio frequency sputtering of the layer followed by wet etching with photolithographic patterning. On the GaAs layer, the micro-hole array pattern was obtained by direct etching through a SiO2 template. Compared with the light scattering effects of the micro-hole-arrayed SiO2 layer, the secondarily etched GaAs rear contact layer showed a significant improvement in external quantum efficiency (EQE) in the wavelength range from 855 to 1000 nm that corresponds to the photon absorption wavelength in MQWs.

  4. Photoluminescence and surface photovoltage spectroscopy characterization of highly strained InGaAs/GaAs quantum well structures grown by metal organic vapor phase epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Chan, C.H. [Department of Information Management, St. John' s University, Tamsui, Taipei 251, Taiwan (China); Wu, J.D. [Department of Electronic Engineering, National Taiwan University of Science and Technology, 43 Keelung Road, Section 4, Taipei 106, Taiwan (China); Huang, Y.S., E-mail: ysh@mail.ntust.edu.tw [Department of Electronic Engineering, National Taiwan University of Science and Technology, 43 Keelung Road, Section 4, Taipei 106, Taiwan (China); Hsu, H.P. [Department of Electronic Engineering, Ming Chi University of Technology, Taishan, Taipei 243, Taiwan (China); Tiong, K.K. [Department of Electrical Engineering, National Taiwan Ocean University, Keelung 202, Taiwan (China); Su, Y.K. [Department of Electrical Engineering, National Cheng Kung University, Tainan 701, Taiwan (China)

    2010-12-01

    Photoluminescence (PL) and surface photovoltage spectroscopy (SPS) are used to characterize a series of highly strained In{sub x}Ga{sub 1-x}As/GaAs quantum well (QW) structures grown by metal organic vapor phase epitaxy with different indium compositions (0.395 {<=} x {<=} 0.44) in the temperature range of 20 K {<=} T {<=} 300 K. The PL features show redshift in peak positions and broadened lineshape with increasing indium composition. The S-shaped temperature dependent PL spectra have been attributed to carrier localization effect resulting from the presence of indium clusters at QW interfaces. A lineshape fit of features in the differential surface photovoltage (SPV) spectra has been used to determine the transition energies accurately. At temperature below 100 K, the light-hole (LH) related feature shows a significant phase difference as compared to that of heavy-hole (HH) related features. The phase change of the LH feature can be explained by the existence of type-II configuration for the LH valence band and the process of separation of carriers within the QWs together with possible capture by the interface defect traps. A detailed analysis of the observed phenomena enables the identification of spectral features and to evaluate the band lineup of the QWs. The results demonstrate the usefulness of PL and SPS for the contactless and nondestructive characterization of highly strained InGaAs/GaAs QW structures.

  5. Surface settlements during the tunnel drivage in loose rock. Prognosis, measurement and impact; Oberflaechensetzungen beim Tunnelvortrieb im Lockergestein. Prognose, Messung und Beeinflussung

    Energy Technology Data Exchange (ETDEWEB)

    Fillibeck, Jochen [Technische Univ. Muenchen (Germany). Zentrum fuer Geotechnik

    2012-11-01

    The realistic prediction of supplement in tunnel construction is essential to secure the acceptance of the construction measure in the population. In addition to numerical calculations particularly empirical processes are suitable whose input variables are derived from previous experiences. Empirical methods use the Gaussian function for the description of the settlement trough arising from the tunnelling at the surface. The contribution under consideration describes the method of Fillibeck allowing the determination of the input parameters for shotcrete drivages and shield drivages. This empirical method was derived from a large number of carefully selected and inspected measuring cross-sections.

  6. Effectiveness of oral sucrose and simulated rocking on pain response in preterm neonates.

    Science.gov (United States)

    Johnston, C C; Stremler, R L; Stevens, B J; Horton, L J

    1997-08-01

    Feeding and carrying have been interventions used by caregivers throughout history in relieving distress in infants. Recent studies on the food substance sucrose have elucidated the comforting effect of the taste component of feeding while studies of rocking have examined the comforting effect of the vestibular component of carrying. The purpose of this study was to determine the effectiveness of sucrose and simulated rocking alone and in combination on diminishing pain response in preterm neonates undergoing routine heelstick procedure in the neonatal intensive care unit (NICU). Preterm infants (n = 85) between 25-34 weeks post-conceptual age (PCA) and 2-10 days postnatal age (PNA) were randomly assigned to one of four conditions for routine heelstick procedure. The conditions were (1) sucrose alone: 0.05 ml of 24% sucrose was placed on the anterior surface of the tongue just prior to the lancing of the heel; (2) simulated rocking alone: 15 min prior to and during the heelstick procedure, the infant was swaddled and put on an oscillating mattress; (3) combination of sucrose and simulated rocking; and (4) placebo: 0.05 ml sterile water administered just prior to heelstick. Physiological (heart rate) and behavioural (facial actions) responses from baseline across 90 s following heelstick were scored second-to-second. Facial actions were analysed with repeated measures MANCOVA and heart rate with repeated measures ANCOVA. Behavioural state and gestational age were covariates. The groups that received sucrose alone or in combination with simulated rocking showed less facial actions indicative of pain than the rocking alone or control group. The addition of rocking to the sucrose condition tended to further blunt the facial expression of pain, but this enhancement did not reach a significant level. Heart rate was not decreased by any intervention compared to the control condition. Although the simulated rocking did promote quiet sleep, which has been reported in

  7. Kinematics analysis of a robotic rock grinder

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    With the aim to discover water, life and resources in other planets, robotic sampling instrument is a crucial part of the space exploration robot. To remove dusty and weathered surfaces and expose the fresh rock underneath the planetary surface, a robotic rock grinder is considered to replace the geologist's rock hammer to carry out the geological investigation. A primary prototype of the robotic rock grinder with three degrees of freedom has been developed in this paper. Planetary transmission system is used in the grinding driving system with two inputs (rotation motor and revolution motor) and two outputs (grinding wheel and cutting brush). The grinding wheel with two teeth has been used to abrade the rock. The cutting brush is used to sweep the debris. The third actuator is to feed the grinding system. Kinematics of the grinding system has been analyzed. To get a continuous and smooth fresh face over the rock, grinding trajectory of the grinding wheel has been discussed and planned. Lastly, abrasion experiments have been made to testify the feasibility and the basic function of this system.

  8. A rock-/ice mechanical model for the destabilisation of permafrost rocks

    Science.gov (United States)

    Krautblatter, Michael; Funk, Daniel

    2010-05-01

    The destabilisation of permafrost rocks is commonly attributed to changes in ice-mechanical properties (Davies et al. 2001). The effect of low temperatures on intact rock strength and its mechanical relevance for shear strength and brittle fracture propagation has not been considered yet. But this effect is significant since compressive and tensile strength are reduced by up to 50% and more when rock thaws (Mellor, 1973). Here we show, that the reduction of the shear resistance of rock-rock contacts in joints plays a key role for the onset of larger instabilities in thawing permafrost rocks. Based on a Mohr-Coulomb assumption, we defined a failure criterion of an ice-filled rock cleft, with cohesive rock bridges, contact of rough fracture surfaces, ductile creep of ice and with a representation of rock-ice "failure" mechanisms along the surface and inside the ice body. The synoptic models are based on the principle of superposition, i.e. that shear stress "absorbed" by one component reduces the amount of shear stress applied to the other components. Failure along existing sliding planes can be explained by the impact of temperature on shear stress uptake by creep deformation of ice, the propensity of failure along rock-ice fractures and reduced total friction along rough rock-rock contacts. This model may account for the rapid response of rockslides to warming (reaction time). In the long term, brittle fracture propagation is initialised. Warming reduces the shear stress uptake by total friction and decreases the critical fracture toughness along rock bridges. The latter model accounts for slow subcritical destabilisation of whole rock slopes over decades to millennia, subsequent to the warming impulse (relaxation time). To test the importance of reduced friction, we conducted shearing tests on homogeneous fine-grained limestone specimen taken from a permafrost site (Zugspitze, Germany). In a temperature-controlled shearing box, we repeatedly tested mechanical

  9. Gravitational stresses in anisotropic rock masses

    Science.gov (United States)

    Amadei, B.; Savage, W.Z.; Swolfs, H.S.

    1987-01-01

    This paper presents closed-form solutions for the stress field induced by gravity in anisotropic rock masses. These rocks are assumed to be laterally restrained and are modelled as a homogeneous, orthotropic or transversely isotropic, linearly elastic material. The analysis, constrained by the thermodynamic requirement that strain energy be positive definite, gives the following important result: inclusion of anisotropy broadens the range of permissible values of gravity-induced horizontal stresses. In fact, for some ranges of anisotropic rock properties, it is thermodynamically admissible for gravity-induced horizontal stresses to exceed the vertical stress component; this is not possible for the classical isotropic solution. Specific examples are presented to explore the nature of the gravity-induced stress field in anisotropic rocks and its dependence on the type, degree and orientation of anisotropy with respect to the horizontal ground surface. ?? 1987.

  10. Geochemistry of the alkaline volcanicsubvolcanic rocks of the Fernando de Noronha Archipelago, southern Atlantic Ocean

    Directory of Open Access Journals (Sweden)

    Rosana Peporine Lopes

    Full Text Available The Fernando de Noronha Archipelago presents, on its main island, a centrally-located stratigraphic unit, the Remédios Formation (age around 8 - 12 Ma constituted by basal pyroclastic rocks intruded by dikes, plugs and domes of varied igneous rocks, capped by flows and pyroclastics of mafic to ultramafic rocks of the Quixaba Formation (age around 1 - 3 Ma, which is limited from the underlying unit by an extensive irregular erosion surface. A predominant sodic Remédios series (basanites, tephrites, tephriphonolites, essexite, phonolites can be separated from a moderately potassic Remédios sequence (alkali basalts, trachyandesites, trachytes, both alkaline series showing mostly continuous geochemical trends in variation diagrams for major as well as trace elements, indicating evolution by crystal fractionation (mainly, separation of mafic minerals, including apatites and titanites. There are textural and mineralogical evidences pointing to hybrid origin of some intermediate rocks (e.g., resorbed pyroxene phenocrysts in basaltic trachyandesites, and in some lamprophyres. The primitive Quixaba rocks are mostly melanephelinites and basanites, primitive undersaturated sodic types. Geology (erosion surface, stratigraphy (two distinct units separated by a large time interval, petrography (varied Remédios Formation, more uniform Quixaba unit and geochemistry indicate that the islands represent the activity of a protracted volcanic episode, fueled by intermittent melting of an enriched mantle, not related to asthenospheric plume activity.

  11. Metallogeny of the Lannigou Sedimentary Rock-hosted Disseminated Gold Deposit in Southwestern Guizhou Province, China

    Institute of Scientific and Technical Information of China (English)

    BAO Zhiwei; Jayanta GUHA

    2007-01-01

    The Lannigou deposit is a large-sized sedimentary rock-hosted disseminated gold (SRHDG)deposit located in the Youjiang Basin. It is hosted by the Middle Triassic turbidite. Wall rock alterations, including silicification, pyritization, arsenopyritization, carbonatization and argillization,commonly occur along fractures. PGE study demonstrates that either Permian basalts or Triassic ultrabasic intrusives are unlikely to be the main source of gold mineralization. Coupled with the lack of other magmatic activity in the vicinity of the mining area, an amagmatic origin is proposed. Organic matter compositions and GC-MS analysis of the ores and host rocks show that the organics in the ores and the host rocks have a common source; the organic matter in the ores was mainly indigenous. The positive correlation between S2 and Au contents, along with the common occurrence of organic inclusions, suggest involvement of organic matter in the ore-forming process in terms of promoting Au leaching from the source rocks, making colloidal Au migration possible, as well as hydrocarbon reduction of sulphate. Geological and geochemical characteristics of the Lannigou deposit suggest that it was formed through circulation of meteoric water and probably less importantly organic bearing formation water driven by high geothermal gradient caused by late Yanshanian extension, which leached Au from the source bed, and then migrated as Au-bisulfides and colloidal Au, culminating in deposition by reduction-adsorption and surface complexation of gold onto the growth surface of arsenian pyrite.

  12. Prompt detection of alpha particles from 210Po: another clue to the origin of rock varnish?

    Science.gov (United States)

    Hodge, Vernon F; Farmer, Dennis E; Diaz, Tammy; Orndorff, Richard L

    2005-01-01

    Alpha particles have been measured coming from the surfaces of rocks covered with dark red-brown rock varnish, as well as rocks that appear to have little, if any, varnish. A pronounced peak at 5.3 MeV indicates the presence of 210Po, a short-lived natural-radioactive element. Surface activities for 33 samples range from 0.008 Bq/cm2 to 0.065 Bq/cm2. It is estimated that this nuclide is concentrated 10(11) times in these paper-thin coatings above its concentration in ground-level air. Gamma rays from the decay of 137Cs, a product of testing nuclear weapons some 50 years ago, were also detected. Analysis of samples of varnish stripped from the rock revealed traces of 239,240Pu and 238Pu. The presence of all of these isotopes strongly supports the theory that varnish films derive their building blocks from the atmosphere and, with time, all rocks in arid environments will become coated.

  13. Development of tongue-shaped and multilobate rock glaciers in alpine environments - Interpretations from ground penetrating radar surveys

    Science.gov (United States)

    Degenhardt, John J., Jr.

    2009-08-01

    Rock glaciers occur as lobate or tongue-shaped landforms composed of mixtures of poorly sorted, angular to blocky rock debris and ice. These landforms serve as primary sinks for ice and water storage in mountainous areas and represent transitional forms in the debris transport system, accounting for ~ 60% of all mass transport in some alpine regions. Observations of active (flowing) alpine rock glaciers indicate a common association between the debris that originates from cirque headwalls and the depositional lobes that comprise them. The delivery of this debris to the rock glacier is regulated primarily by the rate of headwall erosion and the point of origin of debris along the headwall. These factors control the relative movement of individual depositional lobes as well as the overall rate of propagation of a rock glacier. In recent geophysical studies, a number of alpine rock glaciers on Prins Karls Forland and Nordenskiöldland, Svalbard, Norway, and the San Juan Mountains of southwest Colorado, USA, have been imaged using ground penetrating radar (GPR) to determine if a relationship exists between the internal structure and surface morphology. Results indicate that the overall morphologic expression of alpine rock glaciers is related to lobate deposition during catastrophic episodes of rockfall that originated from associated cirque headwalls. Longitudinal GPR profiles from alpine rock glaciers examined in this study suggests that the difference in gross morphology between the lobate and tongue-shaped rock glaciers can be attributed primarily (but not exclusively) to cirque geometry, frequency and locations of debris discharge within the cirque, and the trend and magnitude of valley gradient in relation to cirque orientation. Collectively, these factors determine the manner in which high magnitude debris discharges, which seem to be the primary mechanism of formation, accumulate to form these rock glaciers.

  14. Rock Cracking Indices for Improved Tunnel Support Design: A Case Study for Columnar Jointed Rock Masses

    Science.gov (United States)

    Feng, Xia-Ting; Hao, Xian-Jie; Jiang, Quan; Li, Shao-jun; Hudson, John A.

    2016-06-01

    Measurements indicate that the development of cracking is a key feature relating to the strength and collapse of a columnar jointed rock mass. In this context, a new support design method utilising rock cracking indices for columnar jointed rock mass under high stress is proposed to restrain the development of cracking in the surrounding rock mass. The method involves limiting the cracking evolution of the surrounding rock mass by designing the appropriate parameters and time of installation of the support system. Two indices are suggested: the allowable depth of the excavation damaged zone (EDZ); and the allowable damage extent of the rock mass in the EDZ. The method involves limiting the evolution of cracking in the surrounding rock mass by designing the parameters and time of installation of the support system. The support system should have a suitable stiffness and installation time so as to restrain the evolution of the depth and damage extent of the EDZ within the surrounding rock. Therefore, the depth and damage extent of the EDZ, as well as the axial stress in the anchor bolts, are calculated at different distances between the support location and the tunnel working face to find the appropriate stiffness and installation time of the support system. The method has been successfully adopted to determine the thickness of shotcrete, the arrangement and installation time of rockbolts, and other parameters, for five large diversion tunnels at the Baihetan hydropower station, China, which were excavated in columnar jointed rock masses.

  15. Influencing factors on the cooling effect of coarse blocky top-layers on relict rock glaciers

    Science.gov (United States)

    Pauritsch, Marcus; Wagner, Thomas; Mayaud, Cyril; Thalheim, Felix; Kellerer-Pirklbauer, Andreas; Winkler, Gerfried

    2017-04-01

    Coarse blocky material widely occurs in alpine landscapes particularly at the surface of bouldery rock glaciers. Such blocky layers are known to have a cooling effect on the subjacent material because of the enhanced non-conductive heat exchange with the atmosphere. This effect is used for instance by the construction of blocky embankments in the building of railways and roads in permafrost regions to prevent thawing processes. In alpine regions, this cooling effect may have a strong influence on the distribution and conservation of permafrost related to climate warming. The thermal regimes of the blocky surface layers of two comparable - in terms of size, elevation and geology - relict rock glaciers with opposing slope aspects are investigated. Therefore, the influence of the slope aspect-related climatic conditions (mainly the incident solar radiation, wind conditions and snow cover) on the cooling effect of the blocky layers is investigated. Air temperature, ground surface temperature and ground temperature at one meter depth were continuously measured over a period of four years at several locations at the NE-oriented Schöneben Rock Glacier and the adjacent SW-oriented Dürrtal Rock Glacier. At the former, additional data about wind speed and wind direction as well as precipitation are available, which are used to take wind-forced convection and snow cover into consideration. Statistical analyses of the data reveal that the blocky top layer of the Dürrtal Rock Glacier generally exhibits lower temperatures compared to the Schöneben Rock Glacier despite the more radiation-exposed aspect and the related higher solar radiation. However, the data show that the thermal regimes of the surface layers are highly heterogeneous and that data from the individual measurement sites have to be interpreted with caution. High Rayleigh numbers at both rock glaciers show that free convection occurs particularly during winter. Furthermore, wind-forced convection has a high

  16. 川东北碳酸岩储层测井资料的几点认识%A few understanding about the well logging data of carbonate rock reservoir in Northeast Sichuan

    Institute of Scientific and Technical Information of China (English)

    王煊

    2012-01-01

    Compared with the traditional sand/shale formation, the formation in Northeast Sichuan is characterized by high resistivity ,low sonic differential time (SDT) and low natural gamma ray (GR). The quality of well log is influenced by many factors, which result in the complexity in reservoir division and fluid property interpretation. On the basis of obser- vation data, the influencing factors of observed values and differences of the well log were analyzed one by one. These influ- encing factors are consist of borehole size, fissure, lithological character, mud filtrate, formation water resistivity, invasion depth, and so on. In addition, the geological application of the crossed dipoles is synthetically expounded.%与传统砂泥岩地层相比,川东北地区地层常以高电阻率、低声波时差、低自然伽玛为特征。影响测井曲线质量的因素很多,由此造成了储层划分和流体性质解释的难度。结合实测资料,对影响曲线测量值和差异的各种因素逐一进行了分析,这些影响因素包括井眼大小、裂缝、岩性、泥浆滤液和地层水电阻率、侵入深度等。并对交叉偶极子的地质应用进行了综合阐述。

  17. Unearthing a Well-Defined Highly Active Bimetallic W/Ti Precatalyst Anchored on a Single Silica Surface for Metathesis of Propane

    KAUST Repository

    Samantaray, Manoja

    2017-02-10

    Two compatible organometallic complexes, W(Me)(6) (1) and TiNp4 (2), were successively anchored on a highly dehydroxylated single silica support (SiO2-700) to synthesize the well-defined bimetallic precatalyst [(equivalent to Si-O-)W(Me)(5)(equivalent to Si-O-)Ti(Np)(3)] (4). Precatalyst 4 was characterized at the molecular level using advanced surface organometallic chemistry (SOMC) characterization techniques. The strong autocorrelation observed between methyl of W and Ti in H-1-H-1 multiple-quantum NMR spectra demonstrates that W and Ti species are in close proximity to each other. The bimetallic precatalyst 4, with a turnover number (TON) of 9784, proved to be significantly more efficient than the silica-supported monometallic catalyst [(equivalent to Si-O-)W(Me)(5)] (3), with a TON of 98, for propane metathesis at 150 degrees C in a flow reactor. The dramatic improvement in the activity signifies the cooperativity between Ti and W and indicates that the key step of alkane metathesis (C-H bond activation followed by beta-H elimination) occurs on Ti, followed by olefin metathesis, which occurs on W. We have demonstrated the influence and importance of proximity of Ti to W for achieving such a significantly high activity. This is the first report demonstrating the considerably high activity (TON = 9784) in propane metathesis at moderate temperature (150 degrees C) using a well-defined bimetallic system prepared via the SOMC approach.

  18. Tautochrone and Brachistochrone Shape Solutions for Rocking Rigid Bodies

    CERN Document Server

    Glaschke, Patrick

    2016-01-01

    Rocking rigid bodies appear in several shapes in everyday life: As furniture like rocking chairs and rocking cradles or as toys like rocking horses or tilting dolls. The familiar rocking motion of these objects, a non-linear combination of a rigid rotation and a translation of the center of mass, gives rise to a number of interesting dynamical properties. However, their study has received little attention in the literature. This work presents a comprehensive introduction to the dynamics of rocking rigid bodies, including a concise derivation of the equations of motion as well as a general inversion procedure to construct rocking rigid body shapes with specified dynamical properties. Moreover, two novel rigid body shapes are derived - the tautochrone shape and the brachistochrone shape - which represent an intriguing generalization of the well-know tautochrone and brachistochrone curves. In particular, tautochrone shapes offer an alternative construction of a tautochrone pendulum, in addition to Huygens' cyclo...

  19. Characterisation of carbonate rocks from near-surface cross-hole and reflection GPR investigations - A case study from southeast Zealand, Denmark

    DEFF Research Database (Denmark)

    Nielsen, Lars; Looms, Majken Caroline; Hansen, Thomas Mejer

    Carbonates found in the near-surface of southeast Zealand, eastern Denmark, are analogous to deposits serving as groundwater and hydrocarbon reservoirs in the Danish region. The study site is located in the Boesdal limestone quarry. A 20 by 20 m area of the bottom of the quarry was levelled using...... to facilitate deeper imaging of the carbonates. The section studied with the cross-hole data is water-saturated. Simple 1D modelling of the cross-hole data indicates a strong drop in GPR velocity at 7 to 8 m depth. Different 2D inversion strategies are tested for fine scale resolution of the inter...... are included in the inversion algorithm are tested and compared to the results obtained using the more traditional approaches. The GPR investigations may contribute to setting the framework for future fine-grained models designed to simulate fluid and gas flow in groundwater and hydrocarbon reservoirs....

  20. Aespoe Hard Rock Laboratory. Annual Report 2009

    Energy Technology Data Exchange (ETDEWEB)

    2010-12-15

    The Aespoe Hard Rock Laboratory (HRL) is an important part of SKB's work with the design and construction of a deep geological repository for the final disposal of spent nuclear fuel. Aespoe HRL is located in the Simpevarp area in the municipality of Oskarshamn. One of the fundamental reasons behind SKB's decision to construct an underground laboratory was to create opportunities for research, development and demonstration in a realistic and undisturbed rock environment down to repository depth. The underground part of the laboratory consists of a tunnel from the Simpevarp peninsula to the southern part of Aespoe where the tunnel continues in a spiral down to a depth of 460 m. Aespoe HRL has been in operation since 1995 and considerable international interest has been shown in its research, as well as in the development and demonstration tasks. A summary of the work performed at Aespoe HRL during 2009 is given below. Geoscience Geoscientific research is a basic activity at Aespoe HRL. The aim of the current studies is to develop geoscientific models of the Aespoe HRL and increase the understanding of the rock mass properties as well as knowledge of applicable methods of measurement. A main task within the geoscientific field is the development of the Aespoe Site Descriptive Model (SDM) integrating information from the different fields. The main activities in the geoscientific fields have been: (1) Geology evaluation of geological mapping techniques leading to the decision to develop a SKB mapping system and finalization of the mapping of rock surfaces in the new tunnel, (2) Hydrogeology monitoring and storage of data in the computerised Hydro Monitoring System, (3) Geochemistry sampling of groundwater in the yearly campaign and for specific experiments and (4) Rock Mechanics finalised the field tests on thermally-induced spalling in deposition holes and evaluated the effect of counterforce in the deposition holes. Natural barriers At Aespoe HRL

  1. Fire effects on rock images and similar cultural resources [Chapter 5

    Science.gov (United States)

    Roger E. Kelly; Daniel F. McCarthy

    2012-01-01

    Throughout human global history, people have purposely altered natural rock surfaces by drilling, drawing, painting, incising, pecking, abrading and chiseling images into stone. Some rock types that present suitable media surfaces for these activities are fine-grained sandstones and granites, basalts, volcanic tuff, dolomites, and limestones. Commonly called rock...

  2. Corrective Action Decision Document/Closure Report for Corrective Action Unit 546: Injection Well and Surface Releases Nevada Test Site, Nevada, Revision 0

    Energy Technology Data Exchange (ETDEWEB)

    Alfred Wickline

    2008-12-01

    This Corrective Action Decision Document/Closure Report has been prepared for Corrective Action Unit 546, Injection Well and Surface Releases, at the Nevada Test Site, Nevada, in accordance with the Federal Facility Agreement and Consent Order (FFACO, 1996; as amended February 2008). Corrective Action Unit (CAU) 546 is comprised of two corrective action sites (CASs): • 06-23-02, U-6a/Russet Testing Area • 09-20-01, Injection Well The purpose of this Corrective Action Decision Document/Closure Report is to provide justification and documentation supporting the recommendation for closure of CAU 546. To achieve this, corrective action investigation (CAI) activities were performed from May 5 through May 28, 2008, as set forth in the Corrective Action Investigation Plan for Corrective Action Unit 546: Injection Well and Surface Releases, Nevada Test Site, Nevada (NNSA/NSO, 2008). The purpose of the CAI was to fulfill the following data needs as defined during the data quality objective (DQO) process: • Determine whether a contaminant of concern is present at a given CAS. • Determine whether sufficient information is available to evaluate potential corrective action alternatives at each CAS. The CAU 546 dataset from the investigation results was evaluated based on the data quality indicator parameters. This evaluation demonstrated the quality and acceptability of the dataset for use in fulfilling the DQO data needs. Because DQO data needs were met, and corrective actions have been implemented, it has been determined that no further corrective action (based on risk to human receptors) is necessary for the CAU 546 CASs. The U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office provides the following recommendations: • No further corrective actions are needed for CAU 546 CASs. • No Corrective Action Plan is required. • A Notice of Completion to the U.S. Department of Energy, National Nuclear Security Administration Nevada Site

  3. Direction of drilling wells. Wiercenie otworow kierunkowych

    Energy Technology Data Exchange (ETDEWEB)

    Szostak, L.

    1980-01-01

    In the example of the most widespread drilling of vertical wells, an examination is made of the mining-geological and technical-technological reasons and methods for evaluating the amount of their twisting. Methods are presented for stabilizing the drilling shaft, features of drilling vertical wells by turbodrills and groups of wells for freezing rocks. Characteristics are presented for the features of directional drilling, model profiles of directed wells, drilling of wells with assigned deviation of the face from the vertical axis. Possibilities are indicated for controlling the trajectory of movement of the face of the well with the rotary method of drilling, in particular, with the use of a deviating wedge, cement plug, etc., methods of drilling inclined wells on cased and uncased sections. Features are examined of creating and controlling the inclination of a well with the use of turbodrills of different design, technology of drilling and casing of multiple-face wells, drilling of a fan of wells from one position of the drilling unit, for example, with unfavorable relief of the earth's surface and drilling of offshore wells by using floating drilling units.

  4. Two early Holocene rock avalanches in the Bernese Alps (Rinderhorn, Switzerland)

    Science.gov (United States)

    Grämiger, Lorenz M.; Moore, Jeffrey R.; Vockenhuber, Christof; Aaron, Jordan; Hajdas, Irka; Ivy-Ochs, Susan

    2016-09-01

    Large rock avalanches constitute a critical process modulating the evolution of alpine landscapes; however, the relatively infrequent occurrence of these high-magnitude events makes identifying underlying process controls challenging. Here we describe two rock avalanches in the Rinderhorn area of the Bernese Alps, Switzerland, providing new mapping of rock avalanche source areas and deposits, refined volume estimates for each event, runout modeling back-analyses, and absolute age constraint from cosmogenic 36Cl surface exposure dating. Results reveal that the Daubensee rock avalanche released ~ 4 million m3 of limestone sliding from the western crest of the Rinderhorn. Debris ran out across a Lateglacial moraine before reaching the valley bottom and spreading, leaving thin (on average 7 m) deposits across a broad area. The runout resulted in a Fahrböschung angle of 21°. Part of the deposit now lies beneath Lake Daubensee. The Klein Rinderhorn rock avalanche released ~ 37 million m3 of limestone along a dip-slope sliding plane, with a maximum runout distance of 4.3 km and estimated Fahrböschung angle of 14°. Deposits bulked to ~ 47 million m3 running up the opposing slope, with distinct hummocky morphology in the proximal area and a distal longitudinal flow ridge. These deposits were later modified and partly obscured by ice avalanches from the nearby Altels peak. Cosmogenic 36Cl surface exposure dating revealed nearly coincident ages for both rock avalanches of 9.8 ± 0.5 ka. The large lag time between local deglaciation and failure suggests that the events were not directly triggered by deglaciation. Rather, the concurrent exposure ages, also coinciding with the nearby Kander valley rock avalanche as well as paleoseismic records from nearby lakes, strongly suggest seismic triggering.

  5. Mineral chemistry and petrogenesis of the Gurgur Mount volcanic rocks (Northeast Takab

    Directory of Open Access Journals (Sweden)

    Dariush Esmaeily

    2016-12-01

    Full Text Available Andesitic and andesitic-basaltic lavas are widespread over most of the ground surface of the Gurgur area altered mostly by the hydrothermal solutions. The main rock forming minerals in these rocks are plagioclase, pyroxene and olivine affected by the hydrothermal solutions. The altered rocks do contain minerals including calcite, sericite and chlorite. Given the results obtained and the mineral chemistry studies, the clinopyroxenes formed in the area are, chemically, calkalkaline and of diopside-augite type formed in subvolcanic to near surface levels contemporaneous with magma ascending. Plagioclase minerals show zoning textures and lie within the two andesine and albite-oligoclase fields. These units, in terms of total rock chemistry, are classified as the calk-alkaline volcanic rocks formed in the continental arcs. On the other hand, on the trace elements chondrite-normalized diagrams and enriched mantle-normalized multi- element diagrams, the LREE enrichment relative to the HREE is observed. The LILE (i.e. Rb, K and Th and the LREE (e.g. La, Ce and Nd show an enrichment in comparison to the HFSE (Zr, Hf, Nb, Yb, Y and Sm. Given the Nd/Th (1.42-1.15, Zr/Nb (12.27-21.22, Ba/La (18.64-29.77 as well as LILE enrichment associated with depletion in Nb, Ta and Ti, an environment related to the subduction zones can be proposed for the area under study. Moreover, the similarity between the REE distribution pattern and the incompatible elements point to the genetic relationship between these rocks. Finally, on the base of the obtained data, it can be concluded that the volcanic rocks in the Gurgur Mountain were likely formed during the extended magmatism of the Urumieh-Dokhtar in the Cenozoic.

  6. Characterization of rock thermal conductivity by high-resolution optical scanning

    Science.gov (United States)

    Popov, Y.A.; Pribnow, D.F.C.; Sass, J.H.; Williams, C.F.; Burkhardt, H.

    1999-01-01

    We compared thress laboratory methods for thermal conductivity measurements: divided-bar, line-source and optical scanning. These methods are widely used in geothermal and petrophysical studies, particularly as applied to research on cores from deep scientific boreholes. The relatively new optical scanning method has recently been perfected and applied to geophysical problems. A comparison among these methods for determining the thermal conductivity tensor for anisotropic rocks is based on a representative collection of 80 crystalline rock samples from the KTB continental deep borehole (Germany). Despite substantial thermal inhomogeneity of rock thermal conductivity (up to 40-50% variation) and high anisotropy (with ratios of principal values attaining 2 and more), the results of measurements agree very well among the different methods. The discrepancy for measurements along the foliation is negligible (conductivity normal to the foliation reveals somewhat larger differences (3-4%). Optical scanning allowed us to characterize the thermal inhomogeneity of rocks and to identify a three-dimensional anisotropy in thermal conductivity of some gneiss samples. The merits of optical scanning include minor random errors (1.6%), the ability to record the variation of thermal conductivity along the sample, the ability to sample deeply using a slow scanning rate, freedom from constraints for sample size and shape, and quality of mechanical treatment of the sample surface, a contactless mode of measurement, high speed of operation, and the ability to measure on a cylindrical sample surface. More traditional methods remain superior for characterizing bulk conductivity at elevated temperature.Three laboratory methods including divided-bar, line-source and optical scanning are widely applied in geothermal and petrophysical studies. In this study, these three methods were compared for determining the thermal conductivity tensor for anisotropic rocks. For this study, a

  7. Apply high-power fiber laser in oil/gas wells drilling

    Science.gov (United States)

    Jiang, Houman; Guo, Shaofeng; Chen, Minsun; Wang, Wenliang

    2015-05-01

    The concept of using lasers to drill through rock has been discussed in the oil and gas industries since the development of the high-power laser. To evaluate the possibility of fielding a laser drilling system, two laser-related problems have to be investigated. The first is the irradiation effects of laser upon rocks; the second is the effects in laser transmission from the source to the rock deep in the well. This transmission includes two stages: the first stage is the transmission inside a fiber, which is packaged in a cable and has about the same length with the well depth; the second stage refers to the transmission process when the laser leaves the fiber and some transforming optics and transmits to the rock surface, during which the well conditions may impose tough restrictions. In this paper, experiment results of laser irradiation upon siliceous sandstone and granite are reported, and the fiber transmission loss is simulated, considering the main absorbing or scattering mechanisms inside fiber. And the laser transmission from the fiber end to the rock surface, in my view, may impose great challenge on the laser drilling technology.

  8. CRITERIA FOR ROCK ENGINEERING FAILURE

    Institute of Scientific and Technical Information of China (English)

    ZHUDeren; ZHANGYuzhuo

    1995-01-01

    A great number of underground rock projects are maintained in the rock mass which is subject to rock damage and failure development. In many cases, the rock. engineering is still under normal working conditions even though rock is already fails to some extent. This paper introduces two different concepts: rock failure and rock engineering failure. Rock failure is defined as a mechanical state under which an applicable characteristic is changed or lost.However, the rock engineering failure is an engineering state under which an applicable function is changed or lost. The failure of surrounding rocks is the major reason of rock engineering failure. The criterion of rock engineering failure depends on the limit of applicable functions. The rock engineering failure state possesses a corresponding point in rock failure state. In this paper, a description of rock engineering failure criterion is given by simply using a mechanical equation or expression. It is expected that the study of rock engineering failure criterion will be an optimal approach that combines research of rock mechanics with rock engineering problems.

  9. Overview of rock glacier kinematics research in the Swiss Alps

    OpenAIRE

    Delaloye, R.; Lambiel, C; I. Gärtner-Roer

    2010-01-01

    The acceleration of rock glacier surface velocities over the two last decades and the destabilization of several landforms show that permafrost creep conditions are changing in the Alps. This article summarizes and presents current understanding of creep behaviour of rock glaciers in the Swiss Alps and emphasises changes that have occurred over the last years and decades. The almost homogeneous interannual behaviour of rock glaciers despite different geometry and activ...

  10. They will rock you!

    CERN Multimedia

    Anaïs Schaeffer

    2013-01-01

    On 30 September, CERN will be the venue for one of the most prestigious events of the year: the concert for the Bosons&More event, the Organization’s celebration of the remarkable performance of the LHC and all its technical systems, as well as the recent fundamental discoveries. Topping the bill will be the Orchestre de la Suisse Romande, the CERN Choir, the Zürcher Sing-Akademie and the Alan Parsons Live Project rock group, who have joined forces to create an unforgettable evening’s entertainment.   The Orchestre de la Suisse Romande, directed by Maestro Neeme Järvi, artistic and musical director of the OSR. (Image: Grégory Maillot). >>> From the Orchestre de la Suisse Romande… Henk Swinnen, General Manager of the Orchestre de la Suisse Romande (OSR), answers some questions for the CERN Bulletin, just a few days before the event. How did this project come about? When CERN invited us to take part in the B...

  11. Hanford wells

    Energy Technology Data Exchange (ETDEWEB)

    McGhan, V.L.; Damschen, D.W.

    1977-06-01

    The Hanford Site contains about 2200 wells constructed from pre-Hanford Works days to the present. As of June 1977, about 1900 wells still exist, and about 850 of these existing wells were drilled to the ground-water table. About 700 of these wells (including about 24 farm wells) still contain water. The others have become dry through infiltration of sediments or a general lowering of the water table in their vicinity. This report, providing the most complete documentation of wells in and adjacent to the Hanford Site, supersedes all previous compilations of Hanford wells.

  12. Tracer tomography (in) rocks!

    Science.gov (United States)

    Somogyvári, Márk; Jalali, Mohammadreza; Jimenez Parras, Santos; Bayer, Peter

    2016-04-01

    Physical behavior of fractured aquifers is rigorously controlled by the presence of interconnected conductive fractures, as they represent the main pathways for flow and transport. Ideally, they are simulated as a discrete fracture network (DFN) in a model to capture the role of fracture system geometry, i.e. fracture length, height, and width (aperture/transmissivity). Such network may be constrained by prior geological information or direct data resources such as field mapping, borehole logging and geophysics. With the many geometric features, however, calibration of a DFN to measured data is challenging. This is especially the case when spatial properties of a fracture network need to be calibrated to flow and transport data. One way to increase the insight in a fractured rock is by combining the information from multiple field tests. In this study, a tomographic configuration that combines multiple tracer tests is suggested. These tests are conducted from a borehole with different injection levels that act as sources. In a downgradient borehole, the tracer is recorded at different levels or receivers, in order to maximize insight in the spatial heterogeneity of the rock. As tracer here we chose heat, and temperature breakthrough curves are recorded. The recorded tracer data is inverted using a novel stochastic trans-dimensional Markov Chain Monte Carlo procedure. An initial DFN solution is generated and sequentially modified given available geological information, such as expected fracture density, orientation, length distribution, spacing and persistency. During this sequential modification, the DFN evolves in a trans-dimensional inversion space through adding and/or deleting fracture segments. This stochastic inversion algorithm requires a large number of thousands of model runs to converge, and thus using a fast and robust forward model is essential to keep the calculation efficient. To reach this goal, an upwind coupled finite difference method is employed