Development of exploration and monitoring techniques for the sustainable thermal use of the shallow subsurface

NASA Astrophysics Data System (ADS)

Vienken, Thomas; Dietrich, Peter

2013-04-01

The increasing use of shallow geothermal energy, especially the rising numbers of geothermal ground source heat pumps that are installed to nowadays heat entire residential neighborhoods and the increasing use of ground water to cool residential buildings, as well as industrial facilities have led to an increasing need to assess possible effects of the use of shallow geothermal energy and to model subsurface heat transport. Potential effects include depletion of groundwater quality with resulting reduction of ground water ecosystem services. Heat and mass transport by groundwater dispersion and convection may lead to a carryover of effects into groundwater dependent ecosystems. These effects are often not directly accessible. Therefore, conflicting interests between geothermal energy use and groundwater protection as well as conflicting use between geothermal energy users are expected to arise especially in densely populated urban areas where the highest demand for the use of shallow geothermal energy is located but exploitation of shallow geothermal energy is limited and, at the same time, groundwater vulnerability is at its highest. Until now, only limited information about the potential effects of the intensive use of ground source heat pumps are available. Analyses conducted in the course of regulatory permission procedures consider only single applications and often rely on models that are solely parameterized based on standard literature values (e.g. thermal conductivity, porosity, and hydraulic conductivity). In addition, heat transport by groundwater dynamics is not considered. Due to the costs of conventionally applied geothermal in-situ tests (e.g. Geothermal Response Test - GRT) these can often only be applied at larger project scale. In this regard, our study will showcase the necessity for the development of novel geothermal monitoring and exploration concepts and tools based on a case story of a thermal intensively used residential neighborhood. We will show that the development of new monitoring and exploration techniques is the prerequisite for the sustainable thermal use of the shallow subsurface in the framework of a geothermal resource management.

Compositions produced using an in situ heat treatment process

DOEpatents

Roes, Augustinus Wilhelmus Maria; Nair, Vijay; Munsterman, Erwin Hunh; Van Bergen, Petrus Franciscus; Van Den Berg, Franciscus Gondulfus Antonius

2013-05-28

Methods for treating a subsurface formation and compositions produced therefrom are described herein. At least one method for producing hydrocarbons from a subsurface formation includes providing heat to the subsurface formation using an in situ heat treatment process. One or more formation particles may be formed during heating of the subsurface formation. Fluid that includes hydrocarbons and the formation particles may be produced from the subsurface formation. The formation particles in the produced fluid may include cenospheres and have an average particle size of at least 0.5 micrometers.

Compositions produced using an in situ heat treatment process

DOEpatents

Roes, Augustinus Wilhelmus Maria [Houston, TX; Nair, Vijay [Katy, TX; Munsterman, Erwin Henh [Amsterdam, NL; Van Bergen, Petrus Franciscus [Amsterdam, NL; Van Den Berg, Franciscus Gondulfus Antonius

2009-10-20

Systems, methods, and heaters for treating a subsurface formation are described herein. At least one method for producing hydrocarbons from a subsurface formation includes providing heat to the subsurface formation using an in situ heat treatment process. One or more formation particles may be formed during heating of the subsurface formation. Fluid that includes hydrocarbons and the formation particles may be produced from the subsurface formation. The formation particles in the produced fluid may include cenospheres and have an average particle size of at least 0.5 micrometers.

Stability of Gas Hydrates on Continental Margins: Implications of Subsurface Fluid Flow

NASA Astrophysics Data System (ADS)

Nunn, J. A.

2008-12-01

Gas hydrates are found at or just below the sediment-ocean interface in continental margins settings throughout the world. They are also found on land in high latitude regions such as the north slope of Alaska. While gas hydrate occurrence is common, gas hydrates are stable under a fairly restricted range of temperatures and pressures. In a purely conductive thermal regime, near surface temperatures depend on basal heat flow, thermal conductivity of sediments, and temperature at the sediment-water or sediment-air interface. Thermal conductivity depends on porosity and sediment composition. Gas hydrates are most stable in areas of low heat flow and high thermal conductivity which produce low temperature gradients. Older margins with thin continental crust and coarse grained sediments would tend to be colder. Another potentially important control on subsurface temperatures is advective heat transport by recharge/discharge of groundwater. Upward fluid flow depresses temperature gradients over a purely conductive regime with the same heat flow which would make gas hydrates more stable. Downward fluid flow would have the opposite effect. However, regional scale fluid flow may substantially increase heat flow in discharge areas which would destabilize gas hydrates. For example, discharge of topographically driven groundwater along the coast in the Central North Slope of Alaska has increased surface heat flow in some areas by more than 50% over a purely conductive thermal regime. Fluid flow also alters the pressure regime which can affect gas hydrate stability. Modeling results suggest a positive feedback between gas hydrate formation/disassociation and fluid flow. Disassociation of gas hydrates or permafrost due to global warming could increase permeability. This could enhance fluid flow and associated heat transport causing a more rapid and/or more spatially extensive gas hydrate disassociation than predicted solely from conductive propagation of temporal changes in surface or water bottom temperature. Model results from both the North Slope of Alaska and the Gulf of Mexico are compared.

Molten salt as a heat transfer fluid for heating a subsurface formation

DOEpatents

Nguyen, Scott Vinh; Vinegar, Harold J.

2010-11-16

A heating system for a subsurface formation includes a conduit located in an opening in the subsurface formation. An insulated conductor is located in the conduit. A material is in the conduit between a portion of the insulated conductor and a portion of the conduit. The material may be a salt. The material is a fluid at operating temperature of the heating system. Heat transfers from the insulated conductor to the fluid, from the fluid to the conduit, and from the conduit to the subsurface formation.

Development of a Compact, Deep-Penetrating Heat Flow Instrument for Lunar Landers: In-Situ Thermal Conductivity System

NASA Technical Reports Server (NTRS)

Nagihara, S.; Zacny, K.; Hedlund, M.; Taylor, P. T.

2012-01-01

Geothermal heat flow is obtained as a product of the geothermal gradient and the thermal conductivity of the vertical soil/rock/regolith interval penetrated by the instrument. Heat flow measurements are a high priority for the geophysical network missions to the Moon recommended by the latest Decadal Survey and previously the International Lunar Network. One of the difficulties associated with lunar heat flow measurement on a robotic mission is that it requires excavation of a relatively deep (approx 3 m) hole in order to avoid the long-term temporal changes in lunar surface thermal environment affecting the subsurface temperature measurements. Such changes may be due to the 18.6-year-cylcle lunar precession, or may be initiated by presence of the lander itself. Therefore, a key science requirement for heat flow instruments for future lunar missions is to penetrate 3 m into the regolith and to measure both thermal gradient and thermal conductivity. Engineering requirements are that the instrument itself has minimal impact on the subsurface thermal regime and that it must be a low-mass and low-power system like any other science instrumentation on planetary landers. It would be very difficult to meet the engineering requirements, if the instrument utilizes a long (> 3 m) probe driven into the ground by a rotary or percussive drill. Here we report progress in our efforts to develop a new, compact lunar heat flow instrumentation that meets all of these science and engineering requirements.

Heating systems for heating subsurface formations

DOEpatents

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

2011-04-26

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

Thermographic observation of heat transport in solid foams

NASA Astrophysics Data System (ADS)

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

2005-06-01

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

Numerical Simulation of Illumination and Thermal Conditions at the Lunar Poles Using LOLA DTMs

NASA Technical Reports Server (NTRS)

Glaser, P.; Glaser, D.; Oberst, J.; Neumann, G. A.; Mazarico, E.; Siegler, M. A.

2017-01-01

We are interested in illumination conditions and the temperature distribution within the upper two meters of regolith near the lunar poles. Here, areas exist receiving almost constant illumination near areas in permanent shadow, which were identified as potential exploration sites for future missions. For our study a numerical simulation of the illumination and thermal environment for lunar near-polar regions is needed. Our study is based on high-resolution, twenty meters per pixel and 400 x 400 km large polar Digital Terrain Models (DTMs), which were derived from Lunar Orbiter Laser Altimeter (LOLA) data. Illumination conditions were simulated by synthetically illuminating the LOLA DTMs using the horizon method considering the Sun as an extended source. We model polar illumination for the central 50 x 50 km subset and use it as an input at each time-step (2 h) to evaluate the heating of the lunar surface and subsequent conduction in the sub-surface. At surface level we balance the incoming insolation with the subsurface conduction and radiation into space, whereas in the sub-surface we consider conduction with an additional constant radiogenic heat source at the bottom of our two-meter layer. Density is modeled as depth-dependent, the specific heat parameter as temperature-dependent and the thermal conductivity as depth- and temperature-dependent. We implemented a fully implicit finite-volume method in space and backward Euler scheme in time to solve the one-dimensional heat equation at each pixel in our 50 x 50 km DTM. Due to the non-linear dependencies of the parameters mentioned above, Newton's method is employed as the non-linear solver together with the Gauss-Seidel method as the iterative linear solver in each Newton iteration. The software is written in OpenCL and runs in parallel on the GPU cores, which allows for fast computation of large areas and long time scales.

Thermal conductive heating in fractured bedrock: Screening calculations to assess the effect of groundwater influx

NASA Astrophysics Data System (ADS)

Baston, Daniel P.; Kueper, Bernard H.

2009-02-01

A two-dimensional semi-analytical heat transfer solution is developed and a parameter sensitivity analysis performed to determine the relative importance of rock material properties (density, thermal conductivity and heat capacity) and hydrogeological properties (hydraulic gradient, fracture aperture, fracture spacing) on the ability to heat fractured rock using thermal conductive heating (TCH). The solution is developed using a Green's function approach in which an integral equation is constructed for the temperature in the fracture. Subsurface temperature distributions are far more sensitive to hydrogeological properties than material properties. The bulk ground water influx ( q) can provide a good estimate of the extent of influx cooling when influx is low to moderate, allowing the prediction of temperatures during heating without specific knowledge of the aperture and spacing of fractures. Target temperatures may not be reached or may be significantly delayed when the groundwater influx is large.

Effects of Temperature on Solute Transport Parameters in Differently-Textured Soils at Saturated Condition

NASA Astrophysics Data System (ADS)

Hamamoto, S.; Arihara, M.; Kawamoto, K.; Nishimura, T.; Komatsu, T.; Moldrup, P.

2014-12-01

Subsurface warming driven by global warming, urban heat islands, and increasing use of shallow geothermal heating and cooling systems such as the ground source heat pump, potentially causes changes in subsurface mass transport. Therefore, understanding temperature dependency of the solute transport characteristics is essential to accurately assess environmental risks due to increased subsurface temperature. In this study, one-dimensional solute transport experiments were conducted in soil columns under temperature control to investigate effects of temperature on solute transport parameters, such as solute dispersion and diffusion coefficients, hydraulic conductivity, and retardation factor. Toyoura sand, Kaolin clay, and intact loamy soils were used in the experiments. Intact loamy soils were taken during a deep well boring at the Arakawa Lowland in Saitama Prefecture, Japan. In the transport experiments, the core sample with 5-cm diameter and 4-cm height was first isotropically consolidated, whereafter 0.01M KCl solution was injected to the sample from the bottom. The concentrations of K+ and Cl- in the effluents were analyzed by an ion chromatograph to obtain solute breakthrough curves. The solute transport parameters were calculated from the breakthrough curves. The experiments were conducted under different temperature conditions (15, 25, and 40 oC). The retardation factor for the intact loamy soils decreased with increasing temperature, while water permeability increased due to reduced viscosity of water at higher temperature. Opposite, the effect of temperature on solute dispersivity for the intact loamy soils was insignificant. The effects of soil texture on the temperature dependency of the solute transport characteristics will be further investigated from comparison of results from differently-textured samples.

Reinterpretation of Mariner 9 IRIS data on the basis of a simulation of radiative-conductive convective transfer in the dust laden Martian atmosphere

NASA Technical Reports Server (NTRS)

Pallman, A. J.

1974-01-01

Time dependent vertical distributions of atmospheric temperature and static stability were determined by a radiative-convective-conductive heat transfer model attuned to Mariner 9 IRIS radiance data. Of particular interest were conditions of both the dust-laden and dust-free atmosphere in the middle latitudes on Mars during the late S.H. summer season. The numerical model simulates at high spatial and temporal resolution (52 atmospheric and 30 subsurface levels; with a time-step of 7.5 min.) the heat transports in the ground-atmosphere system. The algorithm is based on the solution of the appropriate heating rate equation which includes radiative, molecular-conductive and convective heat transfer terms. Ground and atmosphere are coupled by an internal thermal boundary condition.

Climate reconstruction from borehole temperatures influenced by groundwater flow

NASA Astrophysics Data System (ADS)

Kurylyk, B.; Irvine, D. J.; Tang, W.; Carey, S. K.; Ferguson, G. A. G.; Beltrami, H.; Bense, V.; McKenzie, J. M.; Taniguchi, M.

2017-12-01

Borehole climatology offers advantages over other climate reconstruction methods because further calibration steps are not required and heat is a ubiquitous subsurface property that can be measured from terrestrial boreholes. The basic theory underlying borehole climatology is that past surface air temperature signals are reflected in the ground surface temperature history and archived in subsurface temperature-depth profiles. High frequency surface temperature signals are attenuated in the shallow subsurface, whereas low frequency signals can be propagated to great depths. A limitation of analytical techniques to reconstruct climate signals from temperature profiles is that they generally require that heat flow be limited to conduction. Advection due to groundwater flow can thermally `contaminate' boreholes and result in temperature profiles being rejected for regional climate reconstructions. Although groundwater flow and climate change can result in contrasting or superimposed thermal disturbances, groundwater flow will not typically remove climate change signals in a subsurface thermal profile. Thus, climate reconstruction is still possible in the presence of groundwater flow if heat advection is accommodated in the conceptual and mathematical models. In this study, we derive a new analytical solution for reconstructing surface temperature history from borehole thermal profiles influenced by vertical groundwater flow. The boundary condition for the solution is composed of any number of sequential `ramps', i.e. periods with linear warming or cooling rates, during the instrumented and pre-observational periods. The boundary condition generation and analytical temperature modeling is conducted in a simple computer program. The method is applied to reconstruct climate in Winnipeg, Canada and Tokyo, Japan using temperature profiles recorded in hydrogeologically active environments. The results demonstrate that thermal disturbances due to groundwater flow and climate change must be considered in a holistic manner as opposed to isolating either perturbation as was done in prior analytical studies.

Interpretation of Ground Temperature Anomalies in Hydrothermal Discharge Areas

NASA Astrophysics Data System (ADS)

Price, Adam N.; Lindsey, Cary R.; Fairley, Jerry P.

2017-12-01

Researchers have long noted the potential for shallow hydrothermal fluids to perturb near-surface temperatures. Several investigators have made qualitative or semiquantitative use of elevated surface temperatures; for example, in snowfall calorimetry, or for tracing subsurface flow paths. However, a quantitative framework connecting surface temperature observations with conditions in the subsurface is currently lacking. Here, we model an area of shallow subsurface flow at Burgdorf Hot Springs, a rustic commercial resort in the Payette National Forest, north of McCall, ID, USA. We calibrate the model using shallow (0.2 m depth) ground temperature measurements and overburden thickness estimates from seismic refraction studies. The calibrated model predicts negligible loss of heat energy from the laterally migrating fluids at the Burgdorf site, in spite of the fact that thermal anomalies are observed in the unconsolidated near-surface alluvium. Although elevated near-surface ground temperatures are commonly assumed to result from locally high heat flux, this conflicts with the small apparent heat loss during lateral flow inferred at the Burgdorf site. We hypothesize an alternative explanation for near-surface temperature anomalies that is only weakly dependent on heat flux, and more strongly controlled by the Biot number, a dimensionless parameter that compares the rate at which convection carries heat away from the land surface to the rate at which it is supplied by conduction to the interface.

Characterizing Long-Term Groundwater Conditions and Lithology for the Design of Large-Scale Borehole Heat Exchangers

NASA Astrophysics Data System (ADS)

Smith, David Charles

Construction of large scale ground coupled heat pump (GCHP) systems that operate with hundreds or even thousands of boreholes for the borehole heat exchangers (BHE) has increased in recent years with many coming on line in the past 10 years. Many large institutions are constructing these systems because of their ability to store energy in the subsurface for indoor cooling during the warm summer months and extract that energy for heating during the cool winter months. Despite the increase in GCHP system systems constructed, there have been few long term studies on how these large systems interact with the subsurface. The thermal response test (TRT) is the industry standard for determining the thermal properties of the rock and soil. The TRT is limited in that it can only be used to determine the effective thermal conductivity over the whole length of a single borehole at the time that it is administered. The TRT cannot account for long-term changes in the aquifer saturation, changes in groundwater flow, or characterize different rock and soil units by effectiveness for heat storage. This study established new methods and also the need for the characterization of the subsurface for the purpose of design and long-term monitoring for GCHP systems. These new methods show that characterizing the long-term changes in aquifer saturation and groundwater flow, and characterizing different rock and soil units are an important part of the design and planning process of these systems. A greater understanding of how large-scale GCHP systems interact with the subsurface will result in designs that perform more efficiently over a longer period of time and expensive modifications due to unforeseen changes in system performance will be reduced.

Radio frequency heating for in-situ remediation of DNAPL

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

Kasevich, R.S.

1996-08-01

In-situ radio frequency (RF) heating technology for treating soils contaminated with dense nonaqueous phase liquids (DNAPLs) is described. RF imparts heat to non-conducting materials through the application of carefully controlled RF transmissions, improving contaminant flow characteristics and facilitating separation and removal from subsurface soils. The paper outlines advantages and limitations of RF remediation, process operations, general technology considerations, low permeability media considerations, commercial availability, and costs. Two case histories of RF remediation are briefly summarized. 13 refs., 10 figs.

Inverse geothermal modelling applied to Danish sedimentary basins

NASA Astrophysics Data System (ADS)

Poulsen, Søren E.; Balling, Niels; Bording, Thue S.; Mathiesen, Anders; Nielsen, Søren B.

2017-10-01

This paper presents a numerical procedure for predicting subsurface temperatures and heat-flow distribution in 3-D using inverse calibration methodology. The procedure is based on a modified version of the groundwater code MODFLOW by taking advantage of the mathematical similarity between confined groundwater flow (Darcy's law) and heat conduction (Fourier's law). Thermal conductivity, heat production and exponential porosity-depth relations are specified separately for the individual geological units of the model domain. The steady-state temperature model includes a model-based transient correction for the long-term palaeoclimatic thermal disturbance of the subsurface temperature regime. Variable model parameters are estimated by inversion of measured borehole temperatures with uncertainties reflecting their quality. The procedure facilitates uncertainty estimation for temperature predictions. The modelling procedure is applied to Danish onshore areas containing deep sedimentary basins. A 3-D voxel-based model, with 14 lithological units from surface to 5000 m depth, was built from digital geological maps derived from combined analyses of reflection seismic lines and borehole information. Matrix thermal conductivity of model lithologies was estimated by inversion of all available deep borehole temperature data and applied together with prescribed background heat flow to derive the 3-D subsurface temperature distribution. Modelled temperatures are found to agree very well with observations. The numerical model was utilized for predicting and contouring temperatures at 2000 and 3000 m depths and for two main geothermal reservoir units, the Gassum (Lower Jurassic-Upper Triassic) and Bunter/Skagerrak (Triassic) reservoirs, both currently utilized for geothermal energy production. Temperature gradients to depths of 2000-3000 m are generally around 25-30 °C km-1, locally up to about 35 °C km-1. Large regions have geothermal reservoirs with characteristic temperatures ranging from ca. 40-50 °C, at 1000-1500 m depth, to ca. 80-110 °C, at 2500-3500 m, however, at the deeper parts, most likely, with too low permeability for non-stimulated production.

Development of a Deep-Penetrating, Compact Geothermal Heat Flow System for Robotic Lunar Geophysical Missions

NASA Technical Reports Server (NTRS)

Nagihara, Seiichi; Zacny, Kris; Hedlund, Magnus; Taylor, Patrick T.

2012-01-01

Geothermal heat flow measurements are a high priority for the future lunar geophysical network missions recommended by the latest Decadal Survey of the National Academy. Geothermal heat flow is obtained as a product of two separate measurements of geothermal gradient and thermal conductivity of the regolith/soil interval penetrated by the instrument. The Apollo 15 and 17 astronauts deployed their heat flow probes down to 1.4-m and 2.3-m depths, respectively, using a rotary-percussive drill. However, recent studies show that the heat flow instrument for a lunar mission should be capable of excavating a 3-m deep hole to avoid the effect of potential long-term changes of the surface thermal environment. For a future robotic geophysical mission, a system that utilizes a rotary/percussive drill would far exceed the limited payload and power capacities of the lander/rover. Therefore, we are currently developing a more compact heat flow system that is capable of 3-m penetration. Because the grains of lunar regolith are cohesive and densely packed, the previously proposed lightweight, internal hammering systems (the so-called moles ) are not likely to achieve the desired deep penetration. The excavation system for our new heat flow instrumentation utilizes a stem which winds out of a pneumatically driven reel and pushes its conical tip into the regolith. Simultaneously, gas jets, emitted from the cone tip, loosen and blow away the soil. Lab tests have demonstrated that this proboscis system has much greater excavation capability than a mole-based heat flow system, while it weighs about the same. Thermal sensors are attached along the stem and at the tip of the penetrating cone. Thermal conductivity is measured at the cone tip with a short (1- to 1.5-cm long) needle sensor containing a resistance temperature detector (RTD) and a heater wire. When it is inserted into the soil, the heater is activated. Thermal conductivity of the soil is obtained from the rate of temperature increase during the heating. By stopping during the excavation, it is possible to measure thermal conductivities at different depths. The gas jets are turned off when the penetrating cone reaches the target depth. Then, the stem pushes the needle sensor into the undisturbed soil at the bottom of the hole and carries out a thermal conductivity measurement. When the measurement is complete, the system resumes excavation. RTDs, placed along the stem at short (approx 30 cm) intervals, will monitor long-term temperature stability of the subsurface. Temperature in the shallow subsurface would fluctuate with the diurnal, annual, and precession cycles of the Moon. These thermal waves penetrate to different depths into the regolith. Longterm monitoring of the subsurface temperature would allow us to accurately delineate these cyclic signals and separate them from the signal associated with the outward flow of the Moon s endogenic heat. Further, temperature toward bottom of the 3-m hole should be fairly stable after the heat generated during the excavation dissipates into the surrounding soil. The geothermal gradient may be determined reliably from temperature measurements at the RTDs near the bottom. In order to minimize the heat conduction along the stem from affecting the geothermal gradient measurements, we plan to use low-conductive materials for the stem and develop a mechanism to achieve close coupling between the RTDs and the wall of the excavated hole.

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

NASA Technical Reports Server (NTRS)

Daryabeigi, Kamran; Walker, Sandra P.

2009-01-01

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

Measuring Subsurface Water Fluxes Using a Heat Pulse Sensor

NASA Astrophysics Data System (ADS)

Ochsner, T. E.; Wang, Q.; Horton, R.

2001-12-01

Subsurface water flux is an important parameter in studies of runoff, infiltration, groundwater recharge, and subsurface chemical transport. Heat pulse sensors have been proposed as promising tools for measuring subsurface water fluxes. Our heat pulse probe consists of three 4-cm stainless-steel needles embedded in a waterproof epoxy body. The needles contain resistance heaters and thermocouples. The probes are connected to an external datalogger and power supply and then installed in soil. To measure the water flux, a 15-s heat pulse is generated at the middle needle using the power supply and the resistance heater, and the temperature increases at the needles 6-mm upstream and downstream from the heater are recorded using the thermocouples and datalogger. To date, heat pulse methods have required cumbersome mathematical analysis to calculate soil water flux from this measured data. We present a new mathematical analysis showing that a simple relationship exists between water flux and the ratio of the temperature increase downstream from the line heat source to the temperature increase upstream from the line heat source. The simplicity of this relationship makes heat pulse sensors a more attractive option for measuring subsurface water fluxes.

Lithosphere temperature model and resource assessment for deep geothermal exploration in Hungary

NASA Astrophysics Data System (ADS)

Bekesi, Eszter; van Wees, Jan-Diederik; Vrijlandt, Mark; Lenkey, Laszlo; Horvath, Ferenc

2017-04-01

The demand for deep geothermal energy has increased considerably over the past years. To reveal potential areas for geothermal exploration, it is crucial to have an insight into the subsurface temperature distribution. Hungary is one of the most suitable countries in Europe for geothermal development, as a result of Early and Middle Miocene extension and subsequent thinning of the lithosphere. Hereby we present the results of a new thermal model of Hungary extending from the surface down to the lithosphere-astenosphere boundary (LAB). Subsurface temperatures were calculated through a regular 3D grid with a horizontal resolution of 2.5 km, a vertical resolution of 200 m for the uppermost 7 km, and 3 km down to the depth of the LAB The model solves the heat equation in steady-state, assuming conduction as the main heat transfer mechanism. At the base, it adopts a constant basal temperature or heat flow condition. For the calibration of the model, more than 5000 temperature measurements were collected from the Geothermal Database of Hungary. The model is built up by five sedimentary layers, upper crust, lower crust, and lithospheric mantle, where each layer has its own thermal properties. The prior thermal properties and basal condition of the model is updated through the ensemble smoother with multiple data assimilation technique. The conductive model shows misfits with the observed temperatures, which cannot be explained by neglected transient effects related to lithosphere extension. These anomalies are explained mostly by groundwater flow in Mesozoic carbonates and other porous sedimentary rocks. To account for the effect of heat convection, we use a pseudo-conductive approach by adjusting the thermal conductivity of the layers where fluid flow may occur. After constructing the subsurface temperature model of Hungary, the resource base for EGS (Enhanced Geothermal Systems) is quantified. To this end, we applied a cash-flow model to translate the geological potential into economical potential for different scenarios in Hungary. The calculations were made for each grid cell of the model. Results of the temperature modeling together with the economical resource assessment provide an indication on the potential sites for future EGS in Hungary.

Urban heat fluxes in the subsurface of Cologne, Germany

NASA Astrophysics Data System (ADS)

Zhu, K.; Bayer, P.; Blum, P.

2012-04-01

Urbanization during the last hundred years has led to both environmental and thermal impacts on the subsurface. The urban heat island (UHI) effect is mostly described as an atmospheric phenomenon, where the measured aboveground temperatures in cities are elevated in comparison to undisturbed rural regions. However, UHIs can be found below, as well as above ground. A large amount of anthropogenic heat migrates into the urban subsurface, which also raises the ground temperature and permanently changes the thermal conditions in shallow aquifers. The main objective of our work is to study and determine the urban heat fluxes in Cologne, Germany, and to improve our understanding of the dynamics of subsurface energy fluxes in UHIs. Ideally, our findings will contribute to strategic and more sustainable geothermal use in cities. For a quantitative analysis of the energy fluxes within the subsurface and across the atmospheric boundary, two and three-dimensional coupled numerical flow and heat transport models were developed. The simulation results indicate that during the past hundred years, an average vertical urban heat flux that ranges between 80 and 375 mW m-2 can be deduced. Thermal anomalies have migrated into the local urban aquifer system and they reach a depth of about 150 m. In this context, the influence of the regional groundwater flow on the subsurface heat transport and temperature development is comprehensively discussed.

Determining in-situ thermal conductivity of coarse textured materials through numerical analysis of thermal

NASA Astrophysics Data System (ADS)

Saito, H.; Hamamoto, S.; Moldrup, P.; Komatsu, T.

2013-12-01

Ground source heat pump (GSHP) systems use ground or groundwater as a heat/cooling source, typically by circulating anti-freezing solution inside a vertically installed closed-loop tube known as a U-tube to transfer heat to/from the ground. Since GSHP systems are based on renewable energy and can achieve much higher coefficient of performance (COP) than conventional air source heat pump systems, use of GSHP systems has been rapidly increasing worldwide. However, environmental impacts by GSHP systems including thermal effects on subsurface physical-chemical and microbiological properties have not been fully investigated. To rigorously assess GSHP impact on the subsurface environment, ground thermal properties including thermal conductivity and heat capacity need to be accurately characterized. Ground thermal properties were investigated at two experimental sites at Tokyo University of Agriculture and Technology (TAT) and Saitama University (SA), both located in the Kanto area of Japan. Thermal properties were evaluated both by thermal probe measurements on boring core samples and by performing in-situ Thermal Response Tests (TRT) in 50-80 m deep U-tubes. At both TAT and SU sites, heat-pulse probe measurements gave unrealistic low thermal conductivities for coarse textured materials (dominated by particles > 75 micrometers). Such underestimation can be partly due to poor contact between probe and porous material and partly to markedly decreasing sample water content during drilling, carrying, and storing sandy/gravelly samples. A more reliable approach for estimating in-situ thermal conductivity of coarse textured materials is therefore needed, and may be based on the commonly used TRT test. However, analyses of TRT data is typically based on Kelvin's line source model and provides an average (effective) thermal property for the whole soil profile around the U-tube but not for each geological layer. The main objective of this study was therefore to develop a method for estimating thermal conductivity values of coarse textured layers by numerically analyzing TRT data. A numerical technique combining three-dimensional conductive heat transport and one-dimensional convective heat transport to simulate heat exchange processes between the U-tube and the ground was used. In the numerical simulations, the thermal conductivities for the fine textured layers were kept at the probe-measured values, while the thermal conductivity for the coarse textured layers (constituting around half of the profile depth at both sites) was calibrated. The numerically-based method yielded more reasonable thermal conductivity values for the coarse-textured materials at both TAT and SU sites as compared to the heat pulse probe measurements, while the temperature changes of the heat carry fluid inside the U-tubes were also well simulated.

Cyclic high temperature heat storage using borehole heat exchangers

NASA Astrophysics Data System (ADS)

Boockmeyer, Anke; Delfs, Jens-Olaf; Bauer, Sebastian

2016-04-01

The transition of the German energy supply towards mainly renewable energy sources like wind or solar power, termed "Energiewende", makes energy storage a requirement in order to compensate their fluctuating production and to ensure a reliable energy and power supply. One option is to store heat in the subsurface using borehole heat exchangers (BHEs). Efficiency of thermal storage is increasing with increasing temperatures, as heat at high temperatures is more easily injected and extracted than at temperatures at ambient levels. This work aims at quantifying achievable storage capacities, storage cycle times, injection and extraction rates as well as thermal and hydraulic effects induced in the subsurface for a BHE storage site in the shallow subsurface. To achieve these aims, simulation of these highly dynamic storage sites is performed. A detailed, high-resolution numerical simulation model was developed, that accounts for all BHE components in geometrical detail and incorporates the governing processes. This model was verified using high quality experimental data and is shown to achieve accurate simulation results with excellent fit to the available experimental data, but also leads to large computational times due to the large numerical meshes required for discretizing the highly transient effects. An approximate numerical model for each type of BHE (single U, double U and coaxial) that reduces the number of elements and the simulation time significantly was therefore developed for use in larger scale simulations. The approximate numerical model still includes all BHE components and represents the temporal and spatial temperature distribution with a deviation of less than 2% from the fully discretized model. Simulation times are reduced by a factor of ~10 for single U-tube BHEs, ~20 for double U-tube BHEs and ~150 for coaxial BHEs. This model is then used to investigate achievable storage capacity, injection and extraction rates as well as induced effects for varying storage cycle times, operating conditions and storage set-ups. A sensitivity analysis shows that storage efficiency strongly depends on the number of BHEs composing the storage site and the cycle time. Using a half-yearly cycle of heat injection and extraction with the maximum possible rates shows that the fraction of recovered heat increases with the number of storage cycles used, as initial losses due to heat conduction become smaller. Also, overall recovery rates of 70 to 80% are possible in the set-ups investigated. Temperature distribution in the geological heat storage site is most sensitive to the thermal conductivity of both borehole grouting and storage formation, while storage efficiency is dominated by the thermal conductivity of the storage formation. For the large cycle times of 6 months each used, heat capacity is less sensitive than the heat conductivity. Acknowledgments: This work is part of the ANGUS+ project (www.angusplus.de) and funded by the German Federal Ministry of Education and Research (BMBF) as part of the energy storage initiative "Energiespeicher".

Modeling the effects of the variability of temperature-related dynamic viscosity on the thermal-affected zone of groundwater heat-pump systems

NASA Astrophysics Data System (ADS)

Lo Russo, Stefano; Taddia, Glenda; Cerino Abdin, Elena

2018-06-01

Thermal perturbation in the subsurface produced in an open-loop groundwater heat pump (GWHP) plant is a complex transport phenomenon affected by several factors, including the exploited aquifer's hydrogeological and thermal characteristics, well construction features, and the temporal dynamics of the plant's groundwater abstraction and reinjection system. Hydraulic conductivity has a major influence on heat transport because plume propagation, which occurs primarily through advection, tends to degrade following conductive heat transport and convection within moving water. Hydraulic conductivity is, in turn, influenced by water reinjection because the dynamic viscosity of groundwater varies with temperature. This paper reports on a computational analysis conducted using FEFLOW software to quantify how the thermal-affected zone (TAZ) is influenced by the variation in dynamic viscosity due to reinjected groundwater in a well-doublet scheme. The modeling results demonstrate non-negligible groundwater dynamic-viscosity variation that affects thermal plume propagation in the aquifer. This influence on TAZ calculation was enhanced for aquifers with high intrinsic permeability and/or substantial temperature differences between abstracted and post-heat-pump-reinjected groundwater.

Modeling the effects of the variability of temperature-related dynamic viscosity on the thermal-affected zone of groundwater heat-pump systems

NASA Astrophysics Data System (ADS)

Lo Russo, Stefano; Taddia, Glenda; Cerino Abdin, Elena

2018-01-01

Thermal perturbation in the subsurface produced in an open-loop groundwater heat pump (GWHP) plant is a complex transport phenomenon affected by several factors, including the exploited aquifer's hydrogeological and thermal characteristics, well construction features, and the temporal dynamics of the plant's groundwater abstraction and reinjection system. Hydraulic conductivity has a major influence on heat transport because plume propagation, which occurs primarily through advection, tends to degrade following conductive heat transport and convection within moving water. Hydraulic conductivity is, in turn, influenced by water reinjection because the dynamic viscosity of groundwater varies with temperature. This paper reports on a computational analysis conducted using FEFLOW software to quantify how the thermal-affected zone (TAZ) is influenced by the variation in dynamic viscosity due to reinjected groundwater in a well-doublet scheme. The modeling results demonstrate non-negligible groundwater dynamic-viscosity variation that affects thermal plume propagation in the aquifer. This influence on TAZ calculation was enhanced for aquifers with high intrinsic permeability and/or substantial temperature differences between abstracted and post-heat-pump-reinjected groundwater.

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

PubMed

Wang, Peiyu; Li, Zhencheng; Pei, Yongmao

2018-04-16

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

Importance of solar subsurface heating in ocean general circulation models

NASA Astrophysics Data System (ADS)

Rochford, Peter A.; Kara, A. Birol; Wallcraft, Alan J.; Arnone, Robert A.

2001-12-01

The importance of subsurface heating on surface mixed layer properties in an ocean general circulation model (OGCM) is examined using attenuation of solar irradiance with depth below the ocean surface. The depth-dependent attenuation of subsurface heating is given by global monthly mean fields for the attenuation of photosynthetically available radiation (PAR), kPAR. These global fields of kPAR are derived from Sea-viewing Wide Field-of-view Sensor (SeaWiFS) data on the spectral diffuse attenuation coefficient at 490 nm (k490), and have been processed to have the smoothly varying and continuous coverage necessary for use in OGCM applications. These monthly fields provide the first complete global data sets of subsurface optical fields that can be used for OGCM applications of subsurface heating and bio-optical processes. The effect on global OGCM prediction of sea surface temperature (SST) and surface mixed layer depth (MLD) is examined when solar heating, as given by monthly mean kPAR and PAR fields, is included in the model. It is found that subsurface heating yields a marked increase in the SST predictive skill of the OGCM at low latitudes. No significant improvement in MLD predictive skill is obtained when including subsurface heating. Use of the monthly mean kPAR produces an SST decrease of up to 0.8°C and a MLD increase of up to only 4-5 m for climatological surface forcing, with this primarily confined to the equatorial regions. Remarkably, a constant kPAR value of 0.06 m-1, which is indicative of optically clear open ocean conditions, is found to serve very well for OGCM prediction of SST and MLD over most of the global ocean.

Subsurface Thermal Energy Storage for Improved Heating and Air Conditioning Efficiency

DTIC Science & Technology

2016-11-21

This project involved a field demonstration of subsurface thermal energy storage for improving the geothermal heat pump air conditioning efficiency... geothermal heat pump systems, undesirable heating of the ground may occur. This demonstration was performed at the MCAS, Beaufort, SC, where several...buildings with geothermal heat pump systems were exhibiting excessively high ground loop temperatures. These buildings were retrofitted with dry fluid

Environmental Impacts of a Multi-Borehole Geothermal System: Model Sensitivity Study

NASA Astrophysics Data System (ADS)

Krol, M.; Daemi, N.

2017-12-01

Problems associated with fossil fuel consumption has increased worldwide interest in discovering and developing sustainable energy systems. One such system is geothermal heating, which uses the constant temperature of the ground to heat or cool buildings. Since geothermal heating offers low maintenance, high heating/cooling comfort, and a low carbon footprint, compared to conventional systems, there has been an increasing trend in equipping large buildings with geothermal heating. However, little is known on the potential environmental impact geothermal heating can have on the subsurface, such as the creation of subsurface thermal plumes or changes in groundwater flow dynamics. In the present study, the environmental impacts of a closed-loop, ground source heat pump (GSHP) system was examined with respect to different system parameters. To do this a three-dimensional model, developed using FEFLOW, was used to examine the thermal plumes resulting from ten years of operation of a vertical closed-loop GSHP system with multiple boreholes. A required thermal load typical of an office building located in Canada was calculated and groundwater flow and heat transport in the geological formation was simulated. Consequently, the resulting thermal plumes were studied and a sensitivity analysis was conducted to determine the effect of different parameters like groundwater flow and soil type on the development and movement of thermal plumes. Since thermal plumes can affect the efficiency of a GSHP system, this study provides insight into important system parameters.

Numerical simulations of the impact of seasonal heat storage on source zone emission in a TCE contaminated aquifer

NASA Astrophysics Data System (ADS)

Popp, Steffi; Beyer, Christof; Dahmke, Andreas; Bauer, Sebastian

2016-04-01

In urban regions, with high population densities and heat demand, seasonal high temperature heat storage in the shallow subsurface represents an attractive and efficient option for a sustainable heat supply. In fact, the major fraction of energy consumed in German households is used for room heating and hot water production. Especially in urbanized areas, however, the installation of high temperature heat storage systems is currently restricted due to concerns on negative influences on groundwater quality caused e.g. by possible interactions between heat storages and subsurface contaminants, which are a common problem in the urban subsurface. Detailed studies on the overall impact of the operation of high temperature heat storages on groundwater quality are scarce. Therefore, this work investigates possible interactions between groundwater temperature changes induced by heat storage via borehole heat exchangers and subsurface contaminations by numerical scenario analysis. For the simulation of non-isothermal groundwater flow, and reactive transport processes the OpenGeoSys code is used. A 2D horizontal cross section of a shallow groundwater aquifer is assumed in the simulated scenario, consisting of a sandy sediment typical for Northern Germany. Within the aquifer a residual trichloroethene (TCE) contaminant source zone is present. Temperature changes are induced by a seasonal heat storage placed within the aquifer with scenarios of maximum temperatures of 20°C, 40°C and 60°C, respectively, during heat injection and minimum temperatures of 2°C during heat extraction. In the scenario analysis also the location of the heat storage relative to the TCE source zone and plume was modified. Simulations were performed in a homogeneous aquifer as well as in a set of heterogeneous aquifers with hydraulic conductivity as spatially correlated random fields. In both cases, results show that the temperature increase in the heat plume and the consequential reduction of water viscosity lead to locally increased groundwater flow. Depending on the positioning of the heat storage relative to the TCE contamination, groundwater fluxes hence may be induced to increase within or partially bypass the TCE source zone. At the same time, TCE solubility decreases between 10 and 40 °C, which reduces TCE emission and almost compensates for the effects of a temperature induced increase of groundwater flow through the source zone. In total, the numerical simulations thus show only minor influences of the heat plume on the TCE emission compared to a thermally undisturbed aquifer. Acknowledgments: This work is part of the ANGUS+ project (www.angusplus.de) and funded by the German Federal Ministry of Education and Research (BMBF) as part of the energy storage initiative "Energiespeicher".

Induction heaters used to heat subsurface formations

DOEpatents

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

2012-04-24

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

Lunar thermal measurements in conjunction with Project Apollo

NASA Technical Reports Server (NTRS)

Clark, S. P., Jr.

1973-01-01

Problems related to the feasibility of measuring lunar heat flow at the lunar surface are analyzed, and the findings which required that a drill be developed for lunar use are discussed. Numerical simulations were made of the in situ measurement of lunar thermal conductivity using a circular ring source of heat. The results of these simulations formed the basis for the criteria used in designing a subsurface thermal probe for ALSEP. Preliminary analyses are presented on the data obtained from the Apollo 15 and 17 missions.

Relevance of Tidal Heating on Large TNOs

NASA Technical Reports Server (NTRS)

Saxena, Prabal; Renaud, Joe P.; Henning, Wade G.; Jutzi, Martin; Hurford, Terry A.

2017-01-01

We examine the relevance of tidal heating for large Trans-Neptunian Objects, with a focus on its potential to melt and maintain layers of subsurface liquid water. Depending on their past orbital evolution, tidal heating may be an important part of the heat budget for a number of discovered and hypothetical TNO systems and may enable formation of, and increased access to, subsurface liquid water. Tidal heating induced by the process of despinning is found to be particularly able to compete with heating due to radionuclide decay in a number of different scenarios. In cases where radiogenic heating alone may establish subsurface conditions for liquid water, we focus on the extent by which tidal activity lifts the depth of such conditions closer to the surface. While it is common for strong tidal heating and long lived tides to be mutually exclusive, we find this is not always the case, and highlight when these two traits occur together. We find cases where TNO systems experience tidal heating that is a significant proportion of, or greater than radiogenic heating for periods ranging from100 s of millions to a billion years. For subsurface oceans that contain a small antifreeze component, tidal heating due to very high initial spin states may enable liquid water to be preserved right up to the present day. Of particular interest is the Eris-Dysnomia system, which in those cases may exhibit extant cryovolcanism.

Relevance of tidal heating on large TNOs

NASA Astrophysics Data System (ADS)

Saxena, Prabal; Renaud, Joe P.; Henning, Wade G.; Jutzi, Martin; Hurford, Terry

2018-03-01

We examine the relevance of tidal heating for large Trans-Neptunian Objects, with a focus on its potential to melt and maintain layers of subsurface liquid water. Depending on their past orbital evolution, tidal heating may be an important part of the heat budget for a number of discovered and hypothetical TNO systems and may enable formation of, and increased access to, subsurface liquid water. Tidal heating induced by the process of despinning is found to be particularly able to compete with heating due to radionuclide decay in a number of different scenarios. In cases where radiogenic heating alone may establish subsurface conditions for liquid water, we focus on the extent by which tidal activity lifts the depth of such conditions closer to the surface. While it is common for strong tidal heating and long lived tides to be mutually exclusive, we find this is not always the case, and highlight when these two traits occur together. We find cases where TNO systems experience tidal heating that is a significant proportion of, or greater than radiogenic heating for periods ranging from100‧s of millions to a billion years. For subsurface oceans that contain a small antifreeze component, tidal heating due to very high initial spin states may enable liquid water to be preserved right up to the present day. Of particular interest is the Eris-Dysnomia system, which in those cases may exhibit extant cryovolcanism.

Heating subsurface formations by oxidizing fuel on a fuel carrier

DOEpatents

Costello, Michael; Vinegar, Harold J.

2012-10-02

A method of heating a portion of a subsurface formation includes drawing fuel on a fuel carrier through an opening formed in the formation. Oxidant is supplied to the fuel at one or more locations in the opening. The fuel is combusted with the oxidant to provide heat to the formation.

Subsurface Structure and Thermal History of Icy Satellites from Stereo Topography

NASA Astrophysics Data System (ADS)

Phillips, C. B.; Hammond, N. P.; Roberts, J. H.; Nimmo, F.; Beyer, R. A.; robuchon, G.

2012-12-01

Stereo topography, in combination with numerical modeling, can be used to study the subsurface structure and thermal history of icy satellites. We are using stereo images of Saturn's icy satellites from the Cassini ISS instrument to construct digital elevation models (DEMs). We first extracted topographic profiles of impact craters on Dione and Rhea. Using the current crater depths, we then estimated the initial crater depth and calculated the viscous crater relaxation for each crater. Our results show that 100 km diameter craters on Rhea range from ~10-50% relaxed, while craters with D> 200 km have relaxations of 40-50%. In comparison, craters with D < 100 km on Dione are 30-50% relaxed, while craters with D >100 km were 60-75% relaxed. We then compared these observations with the results of a combined thermal and visco-elastic relaxation model based on the work of Robuchon et al. 2011 and Robuchon and Nimmo 2011. The model for Rhea predicts a maximum crater relaxation between 10% for smaller craters and 40% for larger craters. For Dione, which is modeled as differentiated, the maximum relaxation is even less: ~5% for smaller craters and ~10% for larger craters. Our model thus underpredicts the observed relaxation. We therefore require more heating early in the history of the satellites to produce the observed relaxation, requiring a subsurface ocean layer. Topographic profiles of tectonic features let us use flexure to estimate elastic thickness and therefore heat flux. We fit observations of the height and distance to observed flexural bulges at two sites on Dione to models of a flexing unbroken elastic plate, and found that the elastic thickness was ~2-5 km. This is consistent with work by Nimmo et al. (2011) that suggested an elastic thickness of 1.5-5 km based on long-wavelength topography. With a measurement of average strain of 0.03, we estimate a heat flux between 20-80 mW/m2. This is far higher than the heat flux of ~ 4 mW/m2 expected from radiogenic heating. A tidal heating model with a 50 km thick ocean for Dione (at the time these features were formed) can produce the observed heat flux with e~0.0022, the current value. Without an ocean, our observed heat flux would require a much higher eccentricity. Therefore, we present two lines of evidence that suggest that a subsurface ocean was present on Dione, and perhaps also Rhea, early in their histories. We are currently working on new thermal models that incorporate subsurface oceans. Preliminary results suggest that if the shells are conductive, the ice will be too stiff to permit the observed degree of relaxation, even if the ice shells are relatively thin (100 km). These results further suggest that the ice shells on Dione and Rhea were convecting at the time of crater formation. Subsurface oceans beneath convective ice shells may not have been long-lived, however, as convection cools the interior far more rapidly than it is heated by radioactive decay. Additional heat sources such as tidal dissipation or shock heating by the impacts themselves may be required to prevent oceans from freezing before relaxation is complete. This work was funded by a grant from the NASA Outer Planets Research Program. References: Robuchon, G., et al. Icarus 214, 82-90, 2011. Robuchon, G., and F. Nimmo. Icarus 216, 426-439, 2011. Nimmo, F. et al., GRL 116, E11001, 2011.

Rapid modification of urban land surface temperature during rainfall

NASA Astrophysics Data System (ADS)

Omidvar, H.; Bou-Zeid, E.; Song, J.; Yang, J.; Arwatz, G.; Wang, Z.; Hultmark, M.; Kaloush, K.

2017-12-01

We study the runoff dynamics and heat transfer over urban pavements during rainfall. A kinematic wave approach is combined with heat storage and transfer schemes to develop a model for impervious (with runoff) and pervious (without runoff) pavements. The resulting framework is a numerical prognostic model that can simulate the temperature fields in the subsurface and runoff layers to capture the rapid cooling of the surface, as well as the thermal pollution advected in the runoff. Extensive field measurements were then conducted over experimental pavements in Arizona to probe the physics and better represent the relevant processes in the model, and then to validate the model. The experimental data and the model results were in very good agreements, and their joint analysis elucidated the physics of the rapid heat transfer from the subsurface to the runoff layer. Finally, we apply the developed model to investigate how the various hydrological and thermal properties of the pavements, as well as ambient environmental conditions, modulate the surface and runoff thermal dynamics, what is the relative importance of each of them, and how we can apply the model mitigate the adverse impacts of urbanization.

Gas injection to inhibit migration during an in situ heat treatment process

DOEpatents

Kuhlman, Myron Ira; Vinegar; Harold J.; Baker, Ralph Sterman; Heron, Goren

2010-11-30

Methods of treating a subsurface formation are described herein. Methods for treating a subsurface treatment area in a formation may include introducing a fluid into the formation from a plurality of wells offset from a treatment area of an in situ heat treatment process to inhibit outward migration of formation fluid from the in situ heat treatment process.

Subsurface urban heat islands in German cities.

PubMed

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

2013-01-01

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

Impact of atmospheric forcing on heat content variability in the sub-surface layer in the Japan/East Sea, 1948-2009

NASA Astrophysics Data System (ADS)

Stepanov, Dmitry; Gusev, Anatoly; Diansky, Nikolay

2016-04-01

Based on numerical simulations the study investigates impact of atmospheric forcing on heat content variability of the sub-surface layer in Japan/East Sea (JES), 1948-2009. We developed a model configuration based on a INMOM model and atmospheric forcing extracted from the CORE phase II experiment dataset 1948-2009, which enables to assess impact of only atmospheric forcing on heat content variability of the sub-surface layer of the JES. An analysis of kinetic energy (KE) and total heat content (THC) in the JES obtained from our numerical simulations showed that the simulated circulation of the JES is being quasi-steady state. It was found that the year-mean KE variations obtained from our numerical simulations are similar those extracted from the SODA reanalysis. Comparison of the simulated THC and that extracted from the SODA reanalysis showed significant consistence between them. An analysis of numerical simulations showed that the simulated circulation structure is very similar that obtained from the PALACE floats in the intermediate and abyssal layers in the JES. Using empirical orthogonal function analysis we studied spatial-temporal variability of the heat content of the sub-surface layer in the JES. Based on comparison of the simulated heat content variations with those obtained from natural observations an assessment of the atmospheric forcing impact on the heat content variability was obtained. Using singular value decomposition analysis we considered relationships between the heat content variability and wind stress curl as well as sensible heat flux in winter. It was established the major role of sensible heat flux in decadal variability of the heat content of the sub-surface layer in the JES. The research was supported by the Russian Foundation for Basic Research (grant N 14-05-00255) and the Council on the Russian Federation President Grants (grant N MK-3241.2015.5)

Air-induction aspirator-aerators cut heat loss to the atmosphere

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

Hodel, A.E.

1993-04-01

The efficiency of biological treatment at the Amoco Chemical's Cedar Bayou plant's activated-sludge wastewater-treatment system was reduced when outdoor temperatures fell below 65[degrees]F. Amoco experienced microbe fragmenting and failure to settle in final clarification, especially during winter. Meeting permit standards during winter was a concern. With mechanical aerators, water is pumped upward and thrown into the air. Much heat loss in the aerated basin was from evaporation and conduction of the mechanical aerator spray. The plant's wastewater staff decided to replace the aerators with subsurface, propeller-type aerator-mixers. These air-induction, aspirating aerator-mixers employ a system that eliminates the spray action throughmore » which evaporation and conduction can occur. The aspirator-aeration systems also have saved energy. The units do not have to overcome the forces of gravity, as with mechanical, surface splasher aerators, which required more horsepower and higher energy consumption to throw the water up into the air. The new units can be conveniently turned on and off to match a fluctuating flow. Since the Cedar Bayou plant installed the system, the aspirator-aerators' subsurface mixing capabilities have made winter permit compliance a steadfast routine.« less

Thermal Impact of Medium Deep Borehole Thermal Energy Storage on the Shallow Subsurface

NASA Astrophysics Data System (ADS)

Welsch, Bastian; Schulte, Daniel O.; Rühaak, Wolfram; Bär, Kristian; Sass, Ingo

2017-04-01

Borehole heat exchanger arrays are a well-suited and already widely applied method for exploiting the shallow subsurface as seasonal heat storage. However, in most of the populated regions the shallow subsurface also comprises an important aquifer system used for drinking water production. Thus, the operation of shallow geothermal heat storage systems leads to a significant increase in groundwater temperatures in the proximity of the borehole heat exchanger array. The magnitude of the impact on groundwater quality and microbiology associated with this temperature rise is controversially discussed. Nevertheless, the protection of shallow groundwater resources has priority. Accordingly, water authorities often follow restrictive permission policies for building such storage systems. An alternative approach to avoid this issue is the application of medium deep borehole heat exchanger arrays instead of shallow ones. The thermal impact on shallow aquifers can be significantly reduced as heat is stored at larger depth. Moreover, it can be further diminished by the installation of a thermally insulating materials in the upper section of the borehole heat exchangers. Based on a numerical simulation study, the advantageous effects of medium deep borehole thermal energy storage are demonstrated and quantified. A finite element software is used to model the heat transport in the subsurface in 3D, while the heat transport in the borehole heat exchangers is solved analytically in 1D. For this purpose, an extended analytical solution is implemented, which also allows for the consideration of a thermally insulating borehole section.

Evaluation of 2D ceramic matrix composites in aeroconvective environments

NASA Technical Reports Server (NTRS)

Riccitiello, Salvatore R.; Love, Wendell L.; Balter-Peterson, Aliza

1992-01-01

An evaluation is conducted of a novel ceramic-matrix composite (CMC) material system for use in the aeroconvective-heating environments encountered by the nose caps and wing leading edges of such aerospace vehicles as the Space Shuttle, during orbit-insertion and reentry from LEO. These CMCs are composed of an SiC matrix that is reinforced with Nicalon, Nextel, or carbon refractory fibers in a 2D architecture. The test program conducted for the 2D CMCs gave attention to their subsurface oxidation.

Heat Fluxes and Evaporation Measurements by Multi-Function Heat Pulse Probe: a Laboratory Experiment

NASA Astrophysics Data System (ADS)

Sharma, V.; Ciocca, F.; Hopmans, J. W.; Kamai, T.; Lunati, I.; Parlange, M. B.

2012-04-01

Multi Functional Heat Pulse Probes (MFHPP) are multi-needles probes developed in the last years able to measure temperature, thermal properties such as thermal diffusivity and volumetric heat capacity, from which soil moisture is directly retrieved, and electric conductivity (through a Wenner array). They allow the simultaneous measurement of coupled heat, water and solute transport in porous media, then. The use of only one instrument to estimate different quantities in the same volume and almost at the same time significantly reduces the need to interpolate different measurement types in space and time, increasing the ability to study the interdependencies characterizing the coupled transports, especially of water and heat, and water and solute. A three steps laboratory experiment is realized at EPFL to investigate the effectiveness and reliability of the MFHPP responses in a loamy soil from Conthey, Switzerland. In the first step specific calibration curves of volumetric heat capacity and thermal conductivity as function of known volumetric water content are obtained placing the MFHPP in small samplers filled with the soil homogeneously packed at different saturation degrees. The results are compared with literature values. In the second stage the ability of the MFHPP to measure heat fluxes is tested within a homemade thermally insulated calibration box and results are matched with those by two self-calibrating Heatflux plates (from Huxseflux), placed in the same box. In the last step the MFHPP are used to estimate the cumulative subsurface evaporation inside a small column (30 centimeters height per 8 centimeters inner diameter), placed on a scale, filled with the same loamy soil (homogeneously packed and then saturated) and equipped with a vertical array of four MFHPP inserted close to the surface. The subsurface evaporation is calculated from the difference between the net sensible heat and the net heat storage in the volume scanned by the probes, and the values obtained are matched with the overall evaporation, estimated through the scale in terms of weight loss. A numerical model able to solve the coupled heat-moisture diffusive equations is used to interpolate the obtained measures in the second and third step.

Sour gas injection for use with in situ heat treatment

DOEpatents

Fowler, Thomas David [Houston, TX

2009-11-03

Systems, methods, and heaters for treating a subsurface formation are described herein. At least one method for providing acidic gas to a subsurface formation is described herein. The method may include providing heat from one or more heaters to a portion of a subsurface formation; producing fluids that include one or more acidic gases from the formation using a heat treatment process. At least a portion of one of the acidic gases may be introduced into the formation, or into another formation, through one or more wellbores at a pressure below a lithostatic pressure of the formation in which the acidic gas is introduced.

Determining temperature and thermal properties for heat-based studies of surface-water ground-water interactions: Appendix A of Heat as a tool for studying the movement of ground water near streams (Cir1260)

USGS Publications Warehouse

Stonestrom, David A.; Blasch, Kyle W.; Stonestrom, David A.; Constantz, Jim

2003-01-01

Advances in electronics leading to improved sensor technologies, large-scale circuit integration, and attendant miniaturization have created new opportunities to use heat as a tracer of subsurface flow. Because nature provides abundant thermal forcing at the land surface, heat is particularly useful in studying stream-groundwater interactions. This appendix describes methods for obtaining the thermal data needed in heat-based investigations of shallow subsurface flow.

An Assessment of Subsurface Residual Stress Analysis in SLM Ti-6Al-4V

PubMed Central

Mishurova, Tatiana; Cabeza, Sandra; Artzt, Katia; Haubrich, Jan; Klaus, Manuela; Genzel, Christoph; Requena, Guillermo; Bruno, Giovanni

2017-01-01

Ti-6Al-4V bridges were additively fabricated by selective laser melting (SLM) under different scanning speed conditions, to compare the effect of process energy density on the residual stress state. Subsurface lattice strain characterization was conducted by means of synchrotron diffraction in energy dispersive mode. High tensile strain gradients were found at the frontal surface for samples in an as-built condition. The geometry of the samples promotes increasing strains towards the pillar of the bridges. We observed that the higher the laser energy density during fabrication, the lower the lattice strains. A relief of lattice strains takes place after heat treatment. PMID:28772706

Multi-step heater deployment in a subsurface formation

DOEpatents

Mason, Stanley Leroy [Allen, TX

2012-04-03

A method for installing a horizontal or inclined subsurface heater includes placing a heating section of a heater in a horizontal or inclined section of a wellbore with an installation tool. The tool is uncoupled from the heating section. A lead in section is mechanically and electrically coupled to the heating section of the heater. The lead-in section is located in an angled or vertical section of the wellbore.

Sensitivity of El Niño intensity and timing to preceding subsurface heat magnitude

PubMed Central

Ballester, Joan; Petrova, Desislava; Bordoni, Simona; Ben Cash; García-Díez, Markel; Rodó, Xavier

2016-01-01

Despite extensive ongoing efforts on improving the long-term prediction of El Niño-Southern Oscillation, the predictability in state-of-the-art operational schemes remains limited by factors such as the spring barrier and the influence of atmospheric winds. Recent research suggests that the 2014/15 El Niño (EN) event was stalled as a result of an unusually strong basin-wide easterly wind burst in June, which led to the discharge of a large fraction of the subsurface ocean heat. Here we use observational records and numerical experiments to explore the sensitivity of EN to the magnitude of the heat buildup occurring in the ocean subsurface 21 months in advance. Our simulations suggest that a large increase in heat content during this phase can lead to basin-wide uniform warm conditions in the equatorial Pacific the winter before the occurrence of a very strong EN event. In our model configuration, the system compensates any initial decrease in heat content and naturally evolves towards a new recharge, resulting in a delay of up to one year in the occurrence of an EN event. Both scenarios substantiate the non-linear dependency between the intensity of the subsurface heat buildup and the magnitude and timing of subsequent EN episodes. PMID:27808279

Sensitivity of El Niño intensity and timing to preceding subsurface heat magnitude.

PubMed

Ballester, Joan; Petrova, Desislava; Bordoni, Simona; Ben Cash; García-Díez, Markel; Rodó, Xavier

2016-11-03

Despite extensive ongoing efforts on improving the long-term prediction of El Niño-Southern Oscillation, the predictability in state-of-the-art operational schemes remains limited by factors such as the spring barrier and the influence of atmospheric winds. Recent research suggests that the 2014/15 El Niño (EN) event was stalled as a result of an unusually strong basin-wide easterly wind burst in June, which led to the discharge of a large fraction of the subsurface ocean heat. Here we use observational records and numerical experiments to explore the sensitivity of EN to the magnitude of the heat buildup occurring in the ocean subsurface 21 months in advance. Our simulations suggest that a large increase in heat content during this phase can lead to basin-wide uniform warm conditions in the equatorial Pacific the winter before the occurrence of a very strong EN event. In our model configuration, the system compensates any initial decrease in heat content and naturally evolves towards a new recharge, resulting in a delay of up to one year in the occurrence of an EN event. Both scenarios substantiate the non-linear dependency between the intensity of the subsurface heat buildup and the magnitude and timing of subsequent EN episodes.

Past Performance analysis of HPOTP bearings

NASA Technical Reports Server (NTRS)

Bhat, B. N.; Dolan, F. J.

1982-01-01

The past performance analysis conducted on three High Pressure Oxygen Turbopump (HPOTP) bearings from the Space Shuttle Main Engine is presented. Metallurgical analysis of failed bearing balls and races, and wear track and crack configuration analyses were carried out. In addition, one bearing was tested in laboratory at very high axial loads. The results showed that the cracks were surface initiated and propagated into subsurface locations at relatively small angles. Subsurface cracks were much more extensive than was appeared on the surface. The location of major cracks in the races corresponded to high radial loads rather than high axial loads. There was evidence to suggest that the inner races were heated to elevated temperatures. A failure scenario was developed based on the above findings. According to this scenario the HPOTP bearings are heated by a combination of high loads and high coefficient of friction (poor lubrication). Different methods of extending the HPOTP bearing life are also discussed. These include reduction of axial loads, improvements in bearing design, lubrication and cooling, and use of improved bearing materials.

Heat and mass transport during a groundwater replenishment trial in a highly heterogeneous aquifer

NASA Astrophysics Data System (ADS)

Seibert, Simone; Prommer, Henning; Siade, Adam; Harris, Brett; Trefry, Mike; Martin, Michael

2014-12-01

Changes in subsurface temperature distribution resulting from the injection of fluids into aquifers may impact physiochemical and microbial processes as well as basin resource management strategies. We have completed a 2 year field trial in a hydrogeologically and geochemically heterogeneous aquifer below Perth, Western Australia in which highly treated wastewater was injected for large-scale groundwater replenishment. During the trial, chloride and temperature data were collected from conventional monitoring wells and by time-lapse temperature logging. We used a joint inversion of these solute tracer and temperature data to parameterize a numerical flow and multispecies transport model and to analyze the solute and heat propagation characteristics that prevailed during the trial. The simulation results illustrate that while solute transport is largely confined to the most permeable lithological units, heat transport was also affected by heat exchange with lithological units that have a much lower hydraulic conductivity. Heat transfer by heat conduction was found to significantly influence the complex temporal and spatial temperature distribution, especially with growing radial distance and in aquifer sequences with a heterogeneous hydraulic conductivity distribution. We attempted to estimate spatially varying thermal transport parameters during the data inversion to illustrate the anticipated correlations of these parameters with lithological heterogeneities, but estimates could not be uniquely determined on the basis of the collected data.

Evaluation of geothermal energy as a heat source for the oilsands industry in Northern Alberta (Canada)

NASA Astrophysics Data System (ADS)

Majorowicz, J. A.; Unsworth, M.; Gray, A.; Nieuwenhuis, G.; Babadagli, T.; Walsh, N.; Weides, S.; Verveda, R.

2012-12-01

The extraction and processing of bitumen from the oilsands of Northern Alberta requires very large amounts of heat that is obtained by burning natural gas. At current levels, the gas used represents 6% of Canada's natural gas production. Geothermal energy could potentially provide this heat, thereby reducing both the financial costs and environmental impact of the oilsands industry. The Helmholtz Alberta Initiative is evaluating this application of geothermal energy through an integrated program of geology, geophysics, reservoir simulation and calculations of the cost benefit. A first stage in this evaluation is refining estimates of subsurface temperature beneath Northern Alberta. This has involved three stages: (1) Corrected industrial thermal data have been used to revise estimates of the upper crustal temperatures beneath the oilsands regions in Alberta. The geothermal gradient map produced using heat flow and thermal conductivity for the entire Phanerozoic column suggests that the overall gradient of the entire column is less than the gradients calculated directly from industry measurements. (2) Paleoclimatic corrections must be applied , since this region has experienced a significant increase in surface temperatures since the end of the last ice age causing a perturbation of shallow heat flow. For this reason, estimates of geothermal gradient based on shallow data are not necessarily characteristic of the whole sedimentary column and can lead to errors in temperature prediction at depth. (3) Improved measurements have been made of the thermal conductivity of the crystalline basement rocks (average = 2.9±0.8 W/m K). Thermal conductivity exhibits significant spatial variability and to a large degree controls the temperature conditions in the Precambrian crystalline basement rocks and its heat content at given heat flow-heat generation. When these steps are used to calculate subsurface temperatures, it can be shown that the temperatures required for geothermal energy to provide usable heat for oil sands processing can only be found within the crystalline basement rocks beneath the WCSB. Lower temperature geothermal resources can be found in the 2 km thick layer of sedimentary rocks in the Peace River area and beneath urban centres in Northern Alberta. Modeling shows that heat extraction for oilsands processing with a doublet or triplet of 5km wells, operated for 15 years, could be marginally economic when compared to the currently low gas prices. This type of heat extraction would be economically competitive if the system had a life span greater than 20 years or with higher natural gas prices.

Relative contributions of microbial and infrastructure heat at a crude oil-contaminated site

NASA Astrophysics Data System (ADS)

Warren, Ean; Bekins, Barbara A.

2018-04-01

Biodegradation of contaminants can increase the temperature in the subsurface due to heat generated from exothermic reactions, making temperature observations a potentially low-cost approach for determining microbial activity. For this technique to gain more widespread acceptance, it is necessary to better understand all the factors affecting the measured temperatures. Biodegradation has been occurring at a crude oil-contaminated site near Bemidji, Minnesota for 39 years, creating a quasi-steady-state plume of contaminants and degradation products. A model of subsurface heat generation and transport helps elucidate the contribution of microbial and infrastructure heating to observed temperature increases at this site. We created a steady-state, two-dimensional, heat transport model using previous-published parameter values for physical, chemical and biodegradation properties. Simulated temperature distributions closely match the observed average annual temperatures measured in the contaminated area at the site within less than 0.2 °C in the unsaturated zone and 0.4 °C in the saturated zone. The model results confirm that the observed subsurface heat from microbial activity is due primarily to methane oxidation in the unsaturated zone resulting in a 3.6 °C increase in average annual temperature. Another important source of subsurface heat is from the active, crude-oil pipelines crossing the site. The pipelines impact temperatures for a distance of 200 m and contribute half the heat. Model results show that not accounting for the heat from the pipelines leads to overestimating the degradation rates by a factor of 1.7, demonstrating the importance of identifying and quantifying all heat sources. The model results also highlighted a zone where previously unknown microbial activity is occurring at the site.

Relative contributions of microbial and infrastructure heat at a crude oil-contaminated site.

PubMed

Warren, Ean; Bekins, Barbara A

2018-04-01

Biodegradation of contaminants can increase the temperature in the subsurface due to heat generated from exothermic reactions, making temperature observations a potentially low-cost approach for determining microbial activity. For this technique to gain more widespread acceptance, it is necessary to better understand all the factors affecting the measured temperatures. Biodegradation has been occurring at a crude oil-contaminated site near Bemidji, Minnesota for 39 years, creating a quasi-steady-state plume of contaminants and degradation products. A model of subsurface heat generation and transport helps elucidate the contribution of microbial and infrastructure heating to observed temperature increases at this site. We created a steady-state, two-dimensional, heat transport model using previous-published parameter values for physical, chemical and biodegradation properties. Simulated temperature distributions closely match the observed average annual temperatures measured in the contaminated area at the site within less than 0.2 °C in the unsaturated zone and 0.4 °C in the saturated zone. The model results confirm that the observed subsurface heat from microbial activity is due primarily to methane oxidation in the unsaturated zone resulting in a 3.6 °C increase in average annual temperature. Another important source of subsurface heat is from the active, crude-oil pipelines crossing the site. The pipelines impact temperatures for a distance of 200 m and contribute half the heat. Model results show that not accounting for the heat from the pipelines leads to overestimating the degradation rates by a factor of 1.7, demonstrating the importance of identifying and quantifying all heat sources. The model results also highlighted a zone where previously unknown microbial activity is occurring at the site. Published by Elsevier B.V.

Upscaling the Coupled Water and Heat Transport in the Shallow Subsurface

NASA Astrophysics Data System (ADS)

Sviercoski, R. F.; Efendiev, Y.; Mohanty, B. P.

2018-02-01

Predicting simultaneous movement of liquid water, water vapor, and heat in the shallow subsurface has many practical interests. The demand for multidimensional multiscale models for this region is important given: (a) the critical role that these processes play in the global water and energy balances, (b) that more data from air-borne and space-borne sensors are becoming available for parameterizations of modeling efforts. On the other hand, numerical models that consider spatial variations of the soil properties, termed here as multiscale, are prohibitively expensive. Thus, there is a need for upscaled models that take into consideration these features, and be computationally affordable. In this paper, a multidimensional multiscale model coupling the water flow and heat transfer and its respective upscaled version are proposed. The formulation is novel as it describes the multidimensional and multiscale tensorial versions of the hydraulic conductivity and the vapor diffusivity, taking into account the tortuosity and porosity properties of the medium. It also includes the coupling with the energy balance equation as a boundary describing atmospheric influences at the shallow subsurface. To demonstrate the accuracy of both models, comparisons were made between simulation and field experiments for soil moisture and temperature at 2, 7, and 12 cm deep, during 11 days. The root-mean-square errors showed that the upscaled version of the system captured the multiscale features with similar accuracy. Given the good matching between simulated and field data for near-surface soil temperature, the results suggest that it can be regarded as a 1-D variable.

On the relative role of meridional convergence and downwelling motion during the heat buildup leading to El Niño events

NASA Astrophysics Data System (ADS)

Ballester, Joan; Bordoni, Simona; Petrova, Desislava; Rodó, Xavier

2015-04-01

Despite steady progress in the understanding of El Niño-Southern Oscillation (ENSO) in the past decades, questions remain on the exact mechanisms leading to the onset of El Niño (EN) events. Several authors have highlighted how the subsurface heat buildup in the western tropical Pacific and the recharged phase in equatorial heat content are intrinsic elements of ENSO variability, leading to those changes in zonal wind stress, sea surface temperature and thermocline tilt that characterize the growing and mature phases of EN. Here we use an ensemble of ocean and atmosphere assimilation products to identify the mechanisms contributing to the heat buildup that precedes EN events by about 18-24 months on average. Anomalous equatorward subsurface mass convergence due to meridional Sverdrup transport is found to be an important mechanism of thermocline deepening near and to the east of the dateline. In the warm pool, instead, surface horizontal convergence and downwelling motion have a leading role in subsurface warming, since equatorward mass convergence is weaker and counterbalanced by subsurface zonal divergence. The picture emerging from our results highlights the complexity of the three dimensional dynamic and thermodynamic structure of the tropical Pacific during the heat buildup leading to EN events.

Technical geothermal potential of urban subsurface influenced by land surface effects

NASA Astrophysics Data System (ADS)

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

2016-04-01

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

Assessing the prospective resource base for enhanced geothermal systems in Europe

NASA Astrophysics Data System (ADS)

Limberger, J.; Calcagno, P.; Manzella, A.; Trumpy, E.; Boxem, T.; Pluymaekers, M. P. D.; van Wees, J.-D.

2014-12-01

In this study the resource base for EGS (enhanced geothermal systems) in Europe was quantified and economically constrained, applying a discounted cash-flow model to different techno-economic scenarios for future EGS in 2020, 2030, and 2050. Temperature is a critical parameter that controls the amount of thermal energy available in the subsurface. Therefore, the first step in assessing the European resource base for EGS is the construction of a subsurface temperature model of onshore Europe. Subsurface temperatures were computed to a depth of 10 km below ground level for a regular 3-D hexahedral grid with a horizontal resolution of 10 km and a vertical resolution of 250 m. Vertical conductive heat transport was considered as the main heat transfer mechanism. Surface temperature and basal heat flow were used as boundary conditions for the top and bottom of the model, respectively. If publicly available, the most recent and comprehensive regional temperature models, based on data from wells, were incorporated. With the modeled subsurface temperatures and future technical and economic scenarios, the technical potential and minimum levelized cost of energy (LCOE) were calculated for each grid cell of the temperature model. Calculations for a typical EGS scenario yield costs of EUR 215 MWh-1 in 2020, EUR 127 MWh-1 in 2030, and EUR 70 MWh-1 in 2050. Cutoff values of EUR 200 MWh-1 in 2020, EUR 150 MWh-1 in 2030, and EUR 100 MWh-1 in 2050 are imposed to the calculated LCOE values in each grid cell to limit the technical potential, resulting in an economic potential for Europe of 19 GWe in 2020, 22 GWe in 2030, and 522 GWe in 2050. The results of our approach do not only provide an indication of prospective areas for future EGS in Europe, but also show a more realistic cost determined and depth-dependent distribution of the technical potential by applying different well cost models for 2020, 2030, and 2050.

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

NASA Astrophysics Data System (ADS)

England, C.

2003-05-01

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

Thermal energy creation and transport and X-ray/EUV emission in a thermodynamic MHD CME simulation

NASA Astrophysics Data System (ADS)

Reeves, K.; Mikic, Z.; Torok, T.; Linker, J.; Murphy, N. A.

2017-12-01

We model a CME using the PSI 3D numerical MHD code that includes coronal heating, thermal conduction and radiative cooling in the energy equation. The magnetic flux distribution at 1 Rs is produced by a localized subsurface dipole superimposed on a global dipole field, mimicking the presence of an active region within the global corona. We introduce transverse electric fields near the neutral line in the active region to form a flux rope, then a converging flow is imposed that causes the eruption. We follow the formation and evolution of the current sheet and find that instabilities set in soon after the reconnection commences. We simulate XRT and AIA EUV emission and find that the instabilities manifest as bright features emanating from the reconnection region. We examine the quantities responsible for plasma heating and cooling during the eruption, including thermal conduction, radiation, adiabatic compression and expansion, coronal heating and ohmic heating due to dissipation of currents. We find that the adiabatic compression plays an important role in heating the plasma around the current sheet, especially in the later stages of the eruption when the instabilities are present. Thermal conduction also plays an important role in the transport of thermal energy away from the current sheet region throughout the reconnection process.

Experimental Evaluation of Hot Films on Ceramic Substrates for Skin-Friction Measurement

NASA Technical Reports Server (NTRS)

Noffz, Gregory K.; Lavine, Adrienne S.; Hamory, Philip J.

2003-01-01

An investigation has been performed on the use of low-thermal conductivity, ceramic substrates for hot films intended to measure skin friction. Hot films were deposited on two types of ceramic substrates. Four hot films used composite-ceramic substrates with subsurface thermocouples (TCs), and two hot films were deposited on thin Macor(R) substrates. All six sensors were tested side by side in the wall of the NASA Glenn Research Center 8-ft by 6-ft Supersonic Wind Tunnel (SWT). Data were obtained from zero flow to Mach 1.98 in air. Control measurements were made with three Preston tubes and two boundary-layer rakes. The tests were repeated at two different hot film power levels. All hot films and subsurface TCs functioned throughout the three days of testing. At zero flow, the films on the high-thermal conductivity Macor(R) substrates required approximately twice the power as those on the composite-ceramic substrates. Skin-friction results were consistent with the control measurements. Estimates of the conduction heat losses were made using the embedded TCs but were hampered by variability in coating thicknesses and TC locations.

Parametric Analysis of the feasibility of low-temperature geothermal heat recovery in sedimentary basins

NASA Astrophysics Data System (ADS)

Tomac, I.; Caulk, R.

2016-12-01

The current study explored the feasibility of heat recovery through the installation of heat exchangers in abandoned oil and gas wells. Finite Element Methods (FEM) were employed to determine the effects of various site specific parameters on production fluid temperature. Specifically, the study parameterized depth of well, subsurface temperature gradient, sedimentary rock conductivity, and flow rate. Results show that greater well depth is associated with greater heat flow, with the greatest returns occurring between depths of 1.5 km and 7 km. Beyond 7 km, the rate of return decreases due to a non-linear increase of heat flow combined with a continued linear increase of pumping cost. One cause for the drop of heat flow was the loss of heat as the fluid travels from depth to the surface. Further analyses demonstrated the benefit of an alternative heat exchanger configuration characterized by thermally insulated sections of the upward heat exchanger. These simulations predict production fluid temperature gains between 5 - 10 oC, which may be suitable for geothermal heat pump applications.

Optimal joule heating of the subsurface

DOEpatents

Berryman, James G.; Daily, William D.

1994-01-01

A method for simultaneously heating the subsurface and imaging the effects of the heating. This method combines the use of tomographic imaging (electrical resistance tomography or ERT) to image electrical resistivity distribution underground, with joule heating by electrical currents injected in the ground. A potential distribution is established on a series of buried electrodes resulting in energy deposition underground which is a function of the resistivity and injection current density. Measurement of the voltages and currents also permits a tomographic reconstruction of the resistivity distribution. Using this tomographic information, the current injection pattern on the driving electrodes can be adjusted to change the current density distribution and thus optimize the heating. As the heating changes conditions, the applied current pattern can be repeatedly adjusted (based on updated resistivity tomographs) to affect real time control of the heating.

Integrating experimental and numerical methods for a scenario-based quantitative assessment of subsurface energy storage options

NASA Astrophysics Data System (ADS)

Kabuth, Alina; Dahmke, Andreas; Hagrey, Said Attia al; Berta, Márton; Dörr, Cordula; Koproch, Nicolas; Köber, Ralf; Köhn, Daniel; Nolde, Michael; Tilmann Pfeiffer, Wolf; Popp, Steffi; Schwanebeck, Malte; Bauer, Sebastian

2016-04-01

Within the framework of the transition to renewable energy sources ("Energiewende"), the German government defined the target of producing 60 % of the final energy consumption from renewable energy sources by the year 2050. However, renewable energies are subject to natural fluctuations. Energy storage can help to buffer the resulting time shifts between production and demand. Subsurface geological structures provide large potential capacities for energy stored in the form of heat or gas on daily to seasonal time scales. In order to explore this potential sustainably, the possible induced effects of energy storage operations have to be quantified for both specified normal operation and events of failure. The ANGUS+ project therefore integrates experimental laboratory studies with numerical approaches to assess subsurface energy storage scenarios and monitoring methods. Subsurface storage options for gas, i.e. hydrogen, synthetic methane and compressed air in salt caverns or porous structures, as well as subsurface heat storage are investigated with respect to site prerequisites, storage dimensions, induced effects, monitoring methods and integration into spatial planning schemes. The conceptual interdisciplinary approach of the ANGUS+ project towards the integration of subsurface energy storage into a sustainable subsurface planning scheme is presented here, and this approach is then demonstrated using the examples of two selected energy storage options: Firstly, the option of seasonal heat storage in a shallow aquifer is presented. Coupled thermal and hydraulic processes induced by periodic heat injection and extraction were simulated in the open-source numerical modelling package OpenGeoSys. Situations of specified normal operation as well as cases of failure in operational storage with leaking heat transfer fluid are considered. Bench-scale experiments provided parameterisations of temperature dependent changes in shallow groundwater hydrogeochemistry. As a second example, the option of seasonal hydrogen storage in a deep saline aquifer is considered. The induced thermal and hydraulic multiphase flow processes were simulated. Also, an integrative approach towards geophysical monitoring of gas presence was evaluated by synthetically applying these monitoring methods to the synthetic, however realistically defined numerical storage scenarios. Laboratory experiments provided parameterisations of geochemical effects caused by storage gas leakage into shallow aquifers in cases of sealing failure. Ultimately, the analysis of realistically defined scenarios of subsurface energy storage within the ANGUS+ project allows a quantification of the subsurface space claimed by a storage operation and its induced effects. Acknowledgments: This work is part of the ANGUS+ project (www.angusplus.de) and funded by the German Federal Ministry of Education and Research (BMBF) as part of the energy storage initiative "Energiespeicher".

Tecuamburro Volcano, Guatemala: exploration geothermal gradient drilling and results

USGS Publications Warehouse

Goff, S.J.; Goff, F.; Janik, C.J.

1992-01-01

Results of geological, volcanological, hydrogeochemical, and geophysical field studies conducted in 1988 and 1989 at the Tecuamburro geothermal site, Guatemala, indicate that there is a substantial shallow heat source beneath the area of youngest volcanism. Gases from acid-sulfate springs near Laguna Ixpaco consistently yield maximum estimated subsurface temperatures of 300??C. To obtain information on subsurface temperatures and temperature gradients, stratigraphy, fracturing, hydrothermal alteration, and hydrothermal fluids, a geothermal gradient core hole (TCB-1) was drilled to 808 m low on the northern flank of the Tecuamburro Volcano complex. The hole is located 300 m south of a 300m-diameter phreatic crater. Laguna Ixpaco, dated at 2910 years. TCB-1 temperature logs do not indicate isothermal conditions at depth and the calculated thermal gradient from 500-800 m is 230??C/km. Bottom hole temperature is close to 240??C. Calculated heat flow values are around 350-400 mW/m2. Fluid-inclusion and secondary-alteration studies indicate that veins and secondary minerals were formed at temperatures equal to or slightly less than present temperatures; thus, the Tecuamburro geothermal system may still be heating up. The integration of results from the TCB-1 gradient core hole with results from field studies provides strong evidence that the Tecuamburro area holds great promise for geothermal resource development. ?? 1992.

An analysis of a mixed convection associated with thermal heating in contaminated porous media.

PubMed

Krol, Magdalena M; Johnson, Richard L; Sleep, Brent E

2014-11-15

The occurrence of subsurface buoyant flow during thermal remediation was investigated using a two dimensional electro-thermal model (ETM). The model incorporated electrical current flow associated with electrical resistance heating, energy and mass transport, and density dependent water flow. The model was used to examine the effects of heating on sixteen subsurface scenarios with different applied groundwater fluxes and soil permeabilities. The results were analyzed in terms of the ratio of Rayleigh to thermal Peclet numbers (the buoyancy ratio). It was found that when the buoyancy number was greater than unity and the soil permeability greater than 10(-12) m(2), buoyant flow and contaminant transport were significant. The effects of low permeability layers and electrode placement on heat and mass transport were also investigated. Heating under a clay layer led to flow stagnation zones resulting in the accumulation of contaminant mass and transport into the low permeability layer. The results of this study can be used to develop dimensionless number-based guidelines for site management during subsurface thermal activities. Copyright © 2014 Elsevier B.V. All rights reserved.

Three-phase heaters with common overburden sections for heating subsurface formations

DOEpatents

Vinegar, Harold J [Bellaire, TX

2012-02-14

A heating system for a subsurface formation is described. The heating system includes three substantially u-shaped heaters with first end portions of the heaters being electrically coupled to a single, three-phase wye transformer and second end portions of the heaters being electrically coupled to each other and/or to ground. The three heaters may enter the formation through a first common wellbore and exit the formation through a second common wellbore so that the magnetic fields of the three heaters at least partially cancel out in the common wellbores.

Acoustic sensor for real-time control for the inductive heating process

DOEpatents

Kelley, John Bruce; Lu, Wei-Yang; Zutavern, Fred J.

2003-09-30

Disclosed is a system and method for providing closed-loop control of the heating of a workpiece by an induction heating machine, including generating an acoustic wave in the workpiece with a pulsed laser; optically measuring displacements of the surface of the workpiece in response to the acoustic wave; calculating a sub-surface material property by analyzing the measured surface displacements; creating an error signal by comparing an attribute of the calculated sub-surface material properties with a desired attribute; and reducing the error signal below an acceptable limit by adjusting, in real-time, as often as necessary, the operation of the inductive heating machine.

Subsurface temperatures and surface heat flow in the Michigan Basin and their relationships to regional subsurface fluid movement

USGS Publications Warehouse

Vugrinovich, R.

1989-01-01

Linear regression of 405 bottomhole temperature (BHT) measurements vs. associated depths from Michigan's Lower Peninsula results in the following equation relating BHT and depth: BHT(??C) = 14.5 + 0.0192 ?? depth(m) Temperature residuals, defined as (BHT measured)-(BHT calculated), were determined for each of the 405 BHT's. Areas of positive temperature residuals correspond to areas of regional groundwater discharge (determined from maps of equipotential surface) while areas of negative temperature residuals correspond to areas of regional groundwater recharge. These relationships are observed in the principal aquifers in rocks of Devonian and Ordovician age and in a portion of the principal aquifer in rocks of Silurian age. There is a similar correspondence between high surface heat flow (determined using the silica geothermometer) and regional groundwater discharge areas and low surface heat flow and regional groundwater recharge areas. Post-Jurassic depositional and tectonic histories suggest that the observed coupling of subsurface temperature and groundwater flow systems may have persisted since Jurassic time. Thus the higher subsurface palaeotemperatures (and palaeogeothermal gradients) indicated by recent studies most likely pre-date the Jurassic. ?? 1989.

Role of subsurface ocean in decadal climate predictability over the South Atlantic.

PubMed

Morioka, Yushi; Doi, Takeshi; Storto, Andrea; Masina, Simona; Behera, Swadhin K

2018-06-04

Decadal climate predictability in the South Atlantic is explored by performing reforecast experiments using a coupled general circulation model with two initialization schemes; one is assimilated with observed sea surface temperature (SST) only, and the other is additionally assimilated with observed subsurface ocean temperature and salinity. The South Atlantic is known to undergo decadal variability exhibiting a meridional dipole of SST anomalies through variations in the subtropical high and ocean heat transport. Decadal reforecast experiments in which only the model SST is initialized with the observation do not predict well the observed decadal SST variability in the South Atlantic, while the other experiments in which the model SST and subsurface ocean are initialized with the observation skillfully predict the observed decadal SST variability, particularly in the Southeast Atlantic. In-depth analysis of upper-ocean heat content reveals that a significant improvement of zonal heat transport in the Southeast Atlantic leads to skillful prediction of decadal SST variability there. These results demonstrate potential roles of subsurface ocean assimilation in the skillful prediction of decadal climate variability over the South Atlantic.

Optimal joule heating of the subsurface

DOEpatents

Berryman, J.G.; Daily, W.D.

1994-07-05

A method for simultaneously heating the subsurface and imaging the effects of the heating is disclosed. This method combines the use of tomographic imaging (electrical resistance tomography or ERT) to image electrical resistivity distribution underground, with joule heating by electrical currents injected in the ground. A potential distribution is established on a series of buried electrodes resulting in energy deposition underground which is a function of the resistivity and injection current density. Measurement of the voltages and currents also permits a tomographic reconstruction of the resistivity distribution. Using this tomographic information, the current injection pattern on the driving electrodes can be adjusted to change the current density distribution and thus optimize the heating. As the heating changes conditions, the applied current pattern can be repeatedly adjusted (based on updated resistivity tomographs) to affect real time control of the heating.

Radiogenic heat production in sedimentary rocks of the Gulf of Mexico Basin, south Texas

USGS Publications Warehouse

McKenna, T.E.; Sharp, J.M.

1998-01-01

Radiogenic heat production within the sedimentary section of the Gulf of Mexico basin is a significant source of heat. Radiogenic heat should be included in thermal models of this basin (and perhaps other sedimentary basins). We calculate that radiogenic heat may contribute up to 26% of the overall surface heat-flow density for an area in south Texas. Based on measurements of the radioactive decay rate of ??-particles, potassium concentration, and bulk density, we calculate radiogenic heat production for Stuart City (Lower Cretaceous) limestones, Wilcox (Eocene) sandstones and mudrocks, and Frio (Oligocene) sandstones and mudrocks from south Texas. Heat production rates range from a low of 0.07 ?? 0.01 ??W/m3 in clean Stuart City limestones to 2.21 ?? 0.24??W/m3 in Frio mudrocks. Mean heat production rates for Wilcox sandstones, Frio sandstones, Wilcox mudrocks, and Frio mudrocks are 0.88, 1.19, 1.50, and 1.72 ??W/m3, respectively. In general, the mudrocks produce about 30-40% more heat than stratigraphically equivalent sandstones. Frio rocks produce about 15% more heat than Wilcox rocks per unit volume of clastic rock (sandstone/mudrock). A one-dimensional heat-conduction model indicates that this radiogenic heat source has a significant effect on subsurface temperatures. If a thermal model were calibrated to observed temperatures by optimizing basal heat-flow density and ignoring sediment heat production, the extrapolated present-day temperature of a deeply buried source rock would be overestimated.Radiogenic heat production within the sedimentary section of the Gulf of Mexico basin is a significant source of heat. Radiogenic heat should be included in thermal models of this basin (and perhaps other sedimentary basins). We calculate that radiogenic heat may contribute up to 26% of the overall surface heat-flow density for an area in south Texas. Based on measurements of the radioactive decay rate of ??-particles, potassium concentration, and bulk density, we calculate radiogenic heat production for Stuart City (Lower Cretaceous) limestones, Wilcox (Eocene) sandstones and mudrocks, and Frio (Oligocene) sandstones and mudrocks from south Texas. Heat production rates range from a low of 0.07??0.01 ??W/m3 in clean Stuart City limestones to 2.21??0.24 ??W/m3 in Frio mudrocks. Mean heat production rates for Wilcox sandstones, Frio sandstones, Wilcox mudrocks, and Frio mudrocks are 0.88, 1.19, 1.50, and 1.72 ??W/m3, respectively. In general, the mudrocks produce about 30-40% more heat than stratigraphically equivalent sandstones. Frio rocks produce about 15% more heat than Wilcox rocks per unit volume of clastic rock (sandstone/mudrock). A one-dimensional heat-conduction model indicates that this radiogenic heat source has a significant effect on subsurface temperatures. If a thermal model were calibrated to observed temperatures by optimizing basal heat-flow density and ignoring sediment heat production, the extrapolated present-day temperature of a deeply buried source rock would be overestimated.

Quantifying Subsurface Water and Heat Distribution and its Linkage with Landscape Properties in Terrestrial Environment using Hydro-Thermal-Geophysical Monitoring and Coupled Inverse Modeling

NASA Astrophysics Data System (ADS)

Dafflon, B.; Tran, A. P.; Wainwright, H. M.; Hubbard, S. S.; Peterson, J.; Ulrich, C.; Williams, K. H.

2015-12-01

Quantifying water and heat fluxes in the subsurface is crucial for managing water resources and for understanding the terrestrial ecosystem where hydrological properties drive a variety of biogeochemical processes across a large range of spatial and temporal scales. Here, we present the development of an advanced monitoring strategy where hydro-thermal-geophysical datasets are continuously acquired and further involved in a novel inverse modeling framework to estimate the hydraulic and thermal parameter that control heat and water dynamics in the subsurface and further influence surface processes such as evapotranspiration and vegetation growth. The measured and estimated soil properties are also used to investigate co-interaction between subsurface and surface dynamics by using above-ground aerial imaging. The value of this approach is demonstrated at two different sites, one in the polygonal shaped Arctic tundra where water and heat dynamics have a strong impact on freeze-thaw processes, vegetation and biogeochemical processes, and one in a floodplain along the Colorado River where hydrological fluxes between compartments of the system (surface, vadose zone and groundwater) drive biogeochemical transformations. Results show that the developed strategy using geophysical, point-scale and aerial measurements is successful to delineate the spatial distribution of hydrostratigraphic units having distinct physicochemical properties, to monitor and quantify in high resolution water and heat distribution and its linkage with vegetation, geomorphology and weather conditions, and to estimate hydraulic and thermal parameters for enhanced predictions of water and heat fluxes as well as evapotranspiration. Further, in the Colorado floodplain, results document the potential presence of only periodic infiltration pulses as a key hot moment controlling soil hydro and biogeochemical functioning. In the arctic, results show the strong linkage between soil water content, thermal parameters, thaw layer thickness and vegetation distribution. Overall, results of these efforts demonstrate the value of coupling various datasets at high spatial and temporal resolution to improve predictive understanding of subsurface and surface dynamics.

Temperature of ground water at Philadelphia, Pennsylvania, 1979- 1981

USGS Publications Warehouse

Paulachok, Gary N.

1986-01-01

Anthropogenic heat production has undoubtedly caused increased ground-water temperatures in many parts of Philadelphia, Pennsylvania, as shown by temperatures of 98 samples and logs of 40 wells measured during 1979-81. Most sample temperatures were higher than 12.6 degrees Celsius (the local mean annual air temperature), and many logs depict cooling trends with depth (anomalous gradients). Heating of surface and shallow-subsurface materials has likely caused the elevated temperatures and anomalous gradients. Solar radiation on widespread concrete and asphalt surfaces, fossil-fuel combustion, and radiant losses from buried pipelines containing steam and process chemicals are believed to be the chief sources of heat. Some heat from these and other sources is transferred to deeper zones, mainly by conduction. Temperatures in densely urbanized areas are commonly highest directly beneath the land surface and decrease progressively with depth. Temperatures in sparsely urbanized areas generally follow the natural geothermal gradient and increase downward at about that same rate.

Shallow Chamber & Conduit Behavior of Silicic Magma: A Thermo- and Fluid- Dynamic Parameterization Model of Physical Deformation as Constrained by Geodetic Observations: Case Study; Soufriere Hills Volcano, Montserrat

NASA Astrophysics Data System (ADS)

Gunn de Rosas, C. L.

2013-12-01

The Soufrière Hills Volcano, Montserrat (SHV) is an active, mainly andesitic and well-studied stratovolcano situated at the northern end of the Lesser Antilles Arc subduction zone in the Caribbean Sea. The goal of our research is to create a high resolution 3D subsurface model of the shallow and deeper aspects of the magma storage and plumbing system at SHV. Our model will integrate inversions using continuous and campaign geodetic observations at SHV from 1995 to the present as well as local seismic records taken at various unrest intervals to construct a best-fit geometry, pressure point source and inflation rate and magnitude. We will also incorporate a heterogeneous media in the crust and use the most contemporary understanding of deep crustal- or even mantle-depth 'hot-zone' genesis and chemical evolution of silicic and intermediate magmas to inform the character of the deep edifice influx. Our heat transfer model will be constructed with a modified 'thin shell' enveloping the magma chamber to simulate the insulating or conducting influence of heat-altered chamber boundary conditions. The final forward model should elucidate observational data preceding and proceeding unrest events, the behavioral suite of magma transport in the subsurface environment and the feedback mechanisms that may contribute to eruption triggering. Preliminary hypotheses suggest wet, low-viscosity residual melts derived from 'hot zones' will ascend rapidly to shallower stall-points and that their products (eventually erupted lavas as well as stalled plutonic masses) will experience and display two discrete periods of shallow evolution; a rapid depressurization crystallization event followed by a slower conduction-controlled heat transfer and cooling crystallization. These events have particular implications for shallow magma behaviors, notably inflation, compressibility and pressure values. Visualization of the model with its inversion constraints will be affected with ComSol. Conclusions about the subsurface behavioral suite at SHV will have high applicability to other silicic and intermediate volcanic edifices and may aid in the hazard mitigation associated with volcanic unrest.

Waste heat generation: A comprehensive review.

PubMed

Yeşiller, Nazli; Hanson, James L; Yee, Emma H

2015-08-01

A comprehensive review of heat generation in various types of wastes and of the thermal regime of waste containment facilities is provided in this paper. Municipal solid waste (MSW), MSW incineration ash, and mining wastes were included in the analysis. Spatial and temporal variations of waste temperatures, thermal gradients, thermal properties of wastes, average temperature differentials, and heat generation values are provided. Heat generation was influenced by climatic conditions, mean annual earth temperatures, waste temperatures at the time of placement, cover conditions, and inherent heat generation potential of the specific wastes. Time to onset of heat generation varied between months and years, whereas timelines for overall duration of heat generation varied between years and decades. For MSW, measured waste temperatures were as high as 60-90°C and as low as -6°C. MSW incinerator ash temperatures varied between 5 and 87°C. Mining waste temperatures were in the range of -25 to 65°C. In the wastes analyzed, upward heat flow toward the surface was more prominent than downward heat flow toward the subsurface. Thermal gradients generally were higher for MSW and incinerator ash and lower for mining waste. Based on thermal properties, MSW had insulative qualities (low thermal conductivity), while mining wastes typically were relatively conductive (high thermal conductivity) with ash having intermediate qualities. Heat generation values ranged from -8.6 to 83.1MJ/m(3) and from 0.6 to 72.6MJ/m(3) for MSW and mining waste, respectively and was 72.6MJ/m(3) for ash waste. Conductive thermal losses were determined to range from 13 to 1111MJ/m(3)yr. The data and analysis provided in this review paper can be used in the investigation of heat generation and thermal regime of a wide range of wastes and waste containment facilities located in different climatic regions. Copyright © 2015 Elsevier Ltd. All rights reserved.

Efficient numerical simulation of heat storage in subsurface georeservoirs

NASA Astrophysics Data System (ADS)

Boockmeyer, A.; Bauer, S.

2015-12-01

The transition of the German energy market towards renewable energy sources, e.g. wind or solar power, requires energy storage technologies to compensate for their fluctuating production. Large amounts of energy could be stored in georeservoirs such as porous formations in the subsurface. One possibility here is to store heat with high temperatures of up to 90°C through borehole heat exchangers (BHEs) since more than 80 % of the total energy consumption in German households are used for heating and hot water supply. Within the ANGUS+ project potential environmental impacts of such heat storages are assessed and quantified. Numerical simulations are performed to predict storage capacities, storage cycle times, and induced effects. For simulation of these highly dynamic storage sites, detailed high-resolution models are required. We set up a model that accounts for all components of the BHE and verified it using experimental data. The model ensures accurate simulation results but also leads to large numerical meshes and thus high simulation times. In this work, we therefore present a numerical model for each type of BHE (single U, double U and coaxial) that reduces the number of elements and the simulation time significantly for use in larger scale simulations. The numerical model includes all BHE components and represents the temporal and spatial temperature distribution with an accuracy of less than 2% deviation from the fully discretized model. By changing the BHE geometry and using equivalent parameters, the simulation time is reduced by a factor of ~10 for single U-tube BHEs, ~20 for double U-tube BHEs and ~150 for coaxial BHEs. Results of a sensitivity study that quantify the effects of different design and storage formation parameters on temperature distribution and storage efficiency for heat storage using multiple BHEs are then shown. It is found that storage efficiency strongly depends on the number of BHEs composing the storage site, their distance and the cycle time. The temperature distribution is most sensitive to thermal conductivity of both borehole grouting and storage formation while storage efficiency is mainly controlled by the thermal conductivity of the storage formation.

Applications of Geothermally-Produced Colloidal Silica in Reservoir Management - Smart Gels

DOE Data Explorer

Hunt, Jonathan

2013-01-31

In enhanced geothermal systems (EGS) the reservoir permeability is often enhanced or created using hydraulic fracturing. In hydraulic fracturing, high fluid pressures are applied to confined zones in the subsurface usually using packers to fracture the host rock. This enhances rock permeability and therefore conductive heat transfer to the circulating geothermal fluid (e.g. water or supercritical carbon dioxide). The ultimate goal is to increase or improve the thermal energy production from the subsurface by either optimal designs of injection and production wells or by altering the fracture permeability to create different zones of circulation that can be exploited in geothermal heat extraction. Moreover, hydraulic fracturing can lead to the creation of undesirable short-circuits or fast flow-paths between the injection and extraction wells leading to a short thermal residence time, low heat recovery, and thus a short-life of the EGS. A potential remedy to these problems is to deploy a cementing (blocking, diverting) agent to minimize short-cuts and/or create new circulation cells for heat extraction. A potential diverting agent is the colloidal silica by-product that can be co-produced from geothermal fluids. Silica gels are abundant in various surface and subsurface applications, yet they have not been evaluated for EGS applications. In this study we are investigating the benefits of silica gel deployment on thermal response of an EGS, either by blocking short-circuiting undesirable pathways as a result of diverting the geofluid to other fractures; or creating, within fractures, new circulation cells for harvesting heat through newly active surface area contact. A significant advantage of colloidal silica is that it can be co-produced from geothermal fluids using an inexpensive membrane-based separation technology that was developed previously using DOE-GTP funding. This co-produced silica has properties that potentially make it useful as a fluid diversion agent for subsurface applications. Colloidal silica solutions exist as low-viscosity fluids during their “induction period” but then undergo a rapid increase in viscosity (gelation) to form a solid gel. The length of the induction period can be manipulated by varying the properties of the solution, such as silica concentration and colloid size. We believe it is possible to produce colloidal silica gels suitable for use as diverting agents for blocking undesirable fast-paths which result in short-circuiting the EGS once hydraulic fracturing has been deployed. In addition, the gels could be used in conventional geothermal fields to increase overall energy recovery by modifying flow.

Geophysical imaging and thermal modeling of subsurface morphology and thaw evolution of discontinuous permafrost

NASA Astrophysics Data System (ADS)

McClymont, Alastair F.; Hayashi, Masaki; Bentley, Laurence R.; Christensen, Brendan S.

2013-09-01

our current understanding of permafrost thaw in subarctic regions in response to rising air temperatures, little is known about the subsurface geometry and distribution of discontinuous permafrost bodies in peat-covered, wetland-dominated terrains and their responses to rising temperature. Using electrical resistivity tomography, ground-penetrating radar profiling, and thermal-conduction modeling, we show how the land cover distributions influence thawing of discontinuous permafrost at a study site in the Northwest Territories, Canada. Permafrost bodies in this region occur under forested peat plateaus and have thicknesses of 5-13 m. Our geophysical data reveal different stages of thaw resulting from disturbances within the active layer: from widening and deepening of differential thaw features under small frost-table depressions to complete thaw of permafrost under an isolated bog. By using two-dimensional geometric constraints derived from our geophysics profiles and meteorological data, we model seasonal and interannual changes to permafrost distribution in response to contemporary climatic conditions and changes in land cover. Modeling results show that in this environment (1) differences in land cover have a strong influence on subsurface thermal gradients such that lateral thaw dominates over vertical thaw and (2) in accordance with field observations, thaw-induced subsidence and flooding at the lateral margins of peat plateaus represents a positive feedback that leads to enhanced warming along the margins of peat plateaus and subsequent lateral heat conduction. Based on our analysis, we suggest that subsurface energy transfer processes (and feedbacks) at scales of 1-100 m have a strong influence on overall permafrost degradation rates at much larger scales.

Numerical investigation on the implications of spring temperature and discharge rate with respect to the geothermal background in a fault zone

NASA Astrophysics Data System (ADS)

Jiang, Zhenjiao; Xu, Tianfu; Mariethoz, Gregoire

2018-04-01

Geothermal springs are some of the most obvious indicators of the existence of high-temperature geothermal resources in the subsurface. However, geothermal springs can also occur in areas of low average subsurface temperatures, which makes it difficult to assess exploitable zones. To address this problem, this study quantitatively analyzes the conditions associated with the formation of geothermal springs in fault zones, and numerically investigates the implications that outflow temperature and discharge rate from geothermal springs have on the geothermal background in the subsurface. It is concluded that the temperature of geothermal springs in fault zones is mainly controlled by the recharge rate from the country rock and the hydraulic conductivity in the fault damage zone. Importantly, the topography of the fault trace on the land surface plays an important role in determining the thermal temperature. In fault zones with a permeability higher than 1 mD and a lateral recharge rate from the country rock higher than 1 m3/day, convection plays a dominant role in the heat transport rather than thermal conduction. The geothermal springs do not necessarily occur in the place having an abnormal geothermal background (with the temperature at certain depth exceeding the temperature inferred by the global average continental geothermal gradient of 30 °C/km). Assuming a constant temperature (90 °C here, to represent a normal geothermal background in the subsurface at a depth of 3,000 m), the conditions required for the occurrence of geothermal springs were quantitatively determined.

Subsurface temperature data in Jemez Mountains, New Mexico. Circular 151

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

Reiter, M.; Weidman, C.; Edwards, C.L.

1976-01-01

Temperature data taken in 13 drill tests around the Valles Caldera are presented. Seven of these tests were shallow auger holes (less than approximately 30m), 4 were rotary holes of intermediate depth (140 m to 170 m), and 2 were relatively deep tests (350 m and 730 m). Heat-flow measurements were obtained in the 4 intermediate drill tests whereas only geothermal gradients were measured in the remaining tests. Potential ground-water movement, lack of good thermal conductivity control, and the shallow depth of many of the drill tests makes the heat-flow pattern in the area uncertain. Two trends appear likely: highermore » heat flows are to the western side of the Valles Caldera (as opposed to the eastern side) and heat flows increase rapidly in approaching the margin of the Valles Caldera from the west. Both observations suggest a relatively shallow heat source located beneath the western part of the Valles Caldera.« less

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

NASA Astrophysics Data System (ADS)

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 <3 °C. The thermal-conductivity calculation allowed an evaluation of the depth range in which the palaeoclimatic 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.

Geothermal studies in China

NASA Astrophysics Data System (ADS)

Ji-Yang, Wang; Mo-Xiang, Chen; Ji-An, Wang; Xiao, Deng; Jun, Wang; Hsien-Chieh, Shen; Liang-Ping, Hsiung; Shu-Zhen, Yan; Zhi-Cheng, Fan; Xiu-Wen, Liu; Ge-Shan, Huang; Wen-Ren, Zhang; Hai-Hui, Shao; Rong-Yan, Zhang

1981-01-01

Geothermal studies have been conducted in China continuously since the end of the 1950's with renewed activity since 1970. Three areas of research are defined: (1) fundamental theoretical research on geothermics, including subsurface temperatures, terrestrial heat flow and geothermal modeling; (2) exploration for geothermal resources and exploitation of geothermal energy; and (3) geothermal studies in mines. Regional geothermal studies have been conducted recently in North China and more than 2000 values of subsurface temperature have been obtained. Temperatures at a depth of 300 m generally range from 20 to 25°C with geothermal gradients from 20 to 40°C/km. These values are regarded as an average for the region with anomalies related to geological factors. To date, 22 reliable heat flow data from 17 sites have been obtained in North China and the data have been categorized according to fault block tectonics. The average heat flow value at 16 sites in the north is 1.3 HFU, varying from 0.7 to 1.8 HFU. It is apparent that the North China fault block is characterized by a relatively high heat flow with wide variations in magnitude compared to the mean value for similar tectonic units in other parts of the world. It is suggested that although the North China fault block can be traced back to the Archaean, the tectonic activity has been strengthening since the Mesozoic resulting in so-called "reactivation of platform" with large-scale faulting and magmatism. Geothermal resources in China are extensive; more than 2000 hot springs have been found and there are other manifestations including geysers, hydrothermal explosions, hydrothermal steam, fumaroles, high-temperature fountains, boiling springs, pools of boiling mud, etc. In addition, there are many Meso-Cenozoic sedimentary basins with widespread aquifers containing geothermal water resources in abundance. The extensive exploration and exploitation of these geothermal resources began early in the 1970's. Since then several experimental power stations using thermal water have been set up in Fengshun (Fungshun),

Restoration of the Apollo Heat Flow Experiments Metadata

NASA Technical Reports Server (NTRS)

Nagihara, S.; Stephens, M. K.; Taylor, P. T.; Williams, D. R.; Hills, H. K.; Nakamura, Y.

2015-01-01

Geothermal heat flow probes were deployed on the Apollo 15 and 17 missions as part of the Apollo Lunar Surface Experiments Package (ALSEP). At each landing site, the astronauts drilled 2 holes, 10-m apart, and installed a probe in each. The holes were 1- and 1.5-m deep at the Apollo 15 site and 2.5-m deep at the Apollo 17 sites. The probes monitored surface temperature and subsurface temperatures at different depths. At the Apollo 15 site, the monitoring continued from July 1971 to January 1977. At the Apollo 17 site, it did from December 1972 to September 1977. Based on the observations made through December 1974, Marcus Langseth, the principal investigator of the heat flow experiments (HFE), determined the thermal conductivity of the lunar regolith by mathematically modeling how the seasonal temperature fluctuation propagated down through the regolith. He also determined the temperature unaffected by diurnal and seasonal thermal waves of the regolith at different depths, which yielded the geothermal gradient. By multiplying the thermal gradient and the thermal conductivity, Langseth obtained the endogenic heat flow of the Moon as 21 mW/m(exp 2) at Site 15 and 16 mW/m(exp 2) at Site 17.

In situ methods for measuring thermal properties and heat flux on planetary bodies.

PubMed

Kömle, Norbert I; Hütter, Erika S; Macher, Wolfgang; Kaufmann, Erika; Kargl, Günter; Knollenberg, Jörg; Grott, Matthias; Spohn, Tilman; Wawrzaszek, Roman; Banaszkiewicz, Marek; Seweryn, Karoly; Hagermann, Axel

2011-06-01

The thermo-mechanical properties of planetary surface and subsurface layers control to a high extent in which way a body interacts with its environment, in particular how it responds to solar irradiation and how it interacts with a potentially existing atmosphere. Furthermore, if the natural temperature profile over a certain depth can be measured in situ, this gives important information about the heat flux from the interior and thus about the thermal evolution of the body. Therefore, in most of the recent and planned planetary lander missions experiment packages for determining thermo-mechanical properties are part of the payload. Examples are the experiment MUPUS on Rosetta's comet lander Philae, the TECP instrument aboard NASA's Mars polar lander Phoenix, and the mole-type instrument HP(3) currently developed for use on upcoming lunar and Mars missions. In this review we describe several methods applied for measuring thermal conductivity and heat flux and discuss the particular difficulties faced when these properties have to be measured in a low pressure and low temperature environment. We point out the abilities and disadvantages of the different instruments and outline the evaluation procedures necessary to extract reliable thermal conductivity and heat flux data from in situ measurements.

Numerical Modeling of Artificial Recharge: Determining Spatial/Temporal Sampling Resolution to Quantify Infiltration Rates and Effective Hydraulic Conductivity

NASA Astrophysics Data System (ADS)

Glose, T. J.; Hausner, M. B.; Lowry, C.

2016-12-01

The accurate, fine scale quantification of groundwater-surface water (GW-SW) interactions over large expanses in hydrologic systems is a fundamental need in order to accurately characterize critical zones of biogeochemical transformation and fluxes, as well as to provide insight into near-surface geologic heterogeneity. Paired fiber-optic distributed temperature sensing (FO-DTS) is a tool that is capable of synoptically sampling hydrologic systems, allowing GW-SW interactions to be examined at a fine scale over large distances. Within managed aquifer recharge (MAR) sites, differential recharge dynamics controlled by bed clogging and subsurface heterogeneity dictate the effectiveness of these sites at infiltrating water. Numerical modeling indicates that the use of paired FO-DTS in an MAR site can provide accurate quantification of flux at the GW-SW interface, as well as provide insight to the areal extent of geologic heterogeneity in the subsurface. However, the lateral and vertical separation of the fiber-optic cables is of vital importance. Here we present a 2-D, fully coupled groundwater flow and heat transport model with prescribed heterogeneity. Following a forward modeling approach, realizations simulating varying fiber-optic cable positioning, differential bed clogging, and hydraulic conductivity variability were analyzed over a suite of scenarios. The results from the model were then used as observations to calculate groundwater recharge rates and calibration targets for an inverse model to estimate subsurface heterogeneity.

Method of imaging the electrical conductivity distribution of a subsurface

DOEpatents

Johnson, Timothy C.

2017-09-26

A method of imaging electrical conductivity distribution of a subsurface containing metallic structures with known locations and dimensions is disclosed. Current is injected into the subsurface to measure electrical potentials using multiple sets of electrodes, thus generating electrical resistivity tomography measurements. A numeric code is applied to simulate the measured potentials in the presence of the metallic structures. An inversion code is applied that utilizes the electrical resistivity tomography measurements and the simulated measured potentials to image the subsurface electrical conductivity distribution and remove effects of the subsurface metallic structures with known locations and dimensions.

Continuous Temperature and Water-Level Data Collected for a Heat Tracer Study on a Selected Reach of Tri-State Canal, Western Nebraska, 2007

USGS Publications Warehouse

Hobza, Christopher M.

2008-01-01

The water supply in parts of the North Platte River Basin in the Nebraska Panhandle has been designated as fully appropriated or over appropriated by the Nebraska Department of Natural Resources. Recent legislation (LB 962) requires the North Platte Natural Resources District and the Nebraska Department of Natural Resources to develop an Integrated Management Plan to balance ground- and surface-water supply and demand within the North Platte Natural Resources District. For a ground-water-flow model to accurately simulate existing or future ground-water and surface-water conditions, accurate estimates of specific input variables such as streambed conductance or canal-seepage rates are required. As of 2008, the values input into ground-water models were estimated on the basis of interpreted lithology from test holes and geophysical surveys. Often, contrasts of several orders of magnitude exist for streambed conductance among the various sediment textures present locally, and thin, near-surface layers of fine sediment can clog the streambed, substantially reducing conductance. To accurately quantify the rates of leakage from irrigation canals and estimate ground-water recharge, the U.S. Geological Survey, in cooperation with the North Platte Natural Resources District, collected continuous temperature and water-level data to use heat as a tracer for a selected reach of Tri-State Canal west of Scottsbluff, Nebraska. Continuous records of subsurface temperature, ground-water level, canal stage, and water temperature, and sediment core data are presented in this report. Subsurface temperature was monitored at four vertical sensor arrays of thermocouples installed at various depths beneath the canal bed from March through September 2007. Canal stage and water temperature were measured from June to September 2007. Ground-water level was recorded continuously in an observation well drilled near the subsurface temperature monitoring site. These data sets were collected for use as inputs for a computer model to estimate the vertical hydraulic conductivity. Before the initiation of flow, diurnal variations in subsurface temperature occurred because of daytime heating and nighttime cooling of bed sediment. Flow in Tri-State Canal was first detected on June 16 at the monitoring site as a disruption in the temperature signal in the shallowest thermocouple in all four vertical sensor arrays. This disruption in the temperature pattern occurred in deeper thermocouples at slightly later times during the rapid infiltration of canal water. The ground-water level began to rise approximately 23 hours after flow was first detected at the monitoring site. Canal stage rose for 7 days until the maximum flow capacity of the canal was approached on June 23, 2007. Measured water temperatures ranged from 18 to 25 degrees Celsius (C) while the canal was flowing near maximum capacity. Small diurnal variations of 1.0 to 1.5 degrees C in water temperature were recorded during this time. Measured ground-water levels rose constantly during the entire irrigation season until levels peaked on September 3, 2007, 3 days after diversions to Tri-State Canal ceased.

Radio-interferometric imaging of the subsurface emissions from the planet Mercury

NASA Technical Reports Server (NTRS)

Burns, J. O.; Zeilik, M.; Gisler, G. R.; Borovsky, J. E.; Baker, D. N.

1987-01-01

The distribution of total and polarized intensities from Mercury's subsurface layers have been mapped using VLA observations. The first detection of a hot pole along the Hermean equator is reported and modeled as black-body reradiation from preferential diurnal heating. These observations appear to rule out any internal sources of heat within Mercury. Polarized emission from the limb of the planet is also found, and is understood in terms of the dielectric properties of the Hermean surface.

Stability of ice on the Moon with rough topography

NASA Astrophysics Data System (ADS)

Rubanenko, Lior; Aharonson, Oded

2017-11-01

The heat flux incident upon the surface of an airless planetary body is dominated by solar radiation during the day, and by thermal emission from topography at night. Motivated by the close relationship between this heat flux, the surface temperatures, and the stability of volatiles, we consider the effect of the slope distribution on the temperature distribution and hence prevalence of cold-traps, where volatiles may accumulate over geologic time. We develop a thermophysical model accounting for insolation, reflected and emitted radiation, and subsurface conduction, and use it to examine several idealized representations of rough topography. We show how subsurface conduction alters the temperature distribution of bowl-shaped craters compared to predictions given by past analytic models. We model the dependence of cold-traps on crater geometry and quantify the effect that while deeper depressions cast more persistent shadows, they are often too warm to trap water ice due to the smaller sky fraction and increased reflected and reemitted radiation from the walls. In order to calculate the temperature distribution outside craters, we consider rough random surfaces with a Gaussian slope distribution. Using their derived temperatures and additional volatile stability models, we estimate the potential area fraction of stable water ice on Earth's Moon. For example, surfaces with slope RMS ∼15° (corresponding to length-scales ∼10 m on the lunar surface) located near the poles are found to have a ∼10% exposed cold-trap area fraction. In the subsurface, the diffusion barrier created by the overlaying regolith increases this area fraction to ∼40%. Additionally, some buried water ice is shown to remain stable even beneath temporarily illuminated slopes, making it more readily accessible to future lunar excavation missions. Finally, due to the exponential dependence of stability of ice on temperature, we are able to constrain the maximum thickness of the unstable layer to a few decimeters.

Field study and simulation of diurnal temperature effects on infiltration and variably saturated flow beneath an ephemeral stream

USGS Publications Warehouse

Dudek Ronan, Anne; Prudic, David E.; Thodal, Carl E.; Constantz, Jim

1998-01-01

Two experiments were performed to investigate flow beneath an ephemeral stream and to estimate streambed infiltration rates. Discharge and stream-area measurements were used to determine infiltration rates. Stream and subsurface temperatures were used to interpret subsurface flow through variably saturated sediments beneath the stream. Spatial variations in subsurface temperatures suggest that flow beneath the streambed is dependent on the orientation of the stream in the canyon and the layering of the sediments. Streamflow and infiltration rates vary diurnally: Streamflow is lowest in late afternoon when stream temperature is greatest and highest in early morning when stream temperature is least. The lower afternoon Streamflow is attributed to increased infiltration rates; evapotranspiration is insufficient to account for the decreased Streamflow. The increased infiltration rates are attributed to viscosity effects on hydraulic conductivity from increased stream temperatures. The first set of field data was used to calibrate a two-dimensional variably saturated flow model that includes heat transport. The model was calibrated to (1) temperature fluctuations in the subsurface and (2) infiltration rates determined from measured Streamflow losses. The second set of field data was to evaluate the ability to predict infiltration rates on the basis of temperature measurements alone. Results indicate that the variably saturated subsurface flow depends on downcanyon layering of the sediments. They also support the field observations in indicating that diurnal changes in infiltration can be explained by temperature dependence of hydraulic conductivity. Over the range of temperatures and flows monitored, diurnal stream temperature changes can be used to estimate streambed infiltration rates. It is often impractical to maintain equipment for determining infiltration rates by traditional means; however, once a model is calibrated using both infiltration and temperature data, only relatively inexpensive temperature monitoring can later yield infiltration rates that are within the correct order of magnitude.

The Prediction-Focused Approach: An opportunity for hydrogeophysical data integration and interpretation

NASA Astrophysics Data System (ADS)

Hermans, Thomas; Nguyen, Frédéric; Klepikova, Maria; Dassargues, Alain; Caers, Jef

2017-04-01

Hydrogeophysics is an interdisciplinary field of sciences aiming at a better understanding of subsurface hydrological processes. If geophysical surveys have been successfully used to qualitatively characterize the subsurface, two important challenges remain for a better quantification of hydrological processes: (1) the inversion of geophysical data and (2) their integration in hydrological subsurface models. The classical inversion approach using regularization suffers from spatially and temporally varying resolution and yields geologically unrealistic solutions without uncertainty quantification, making their utilization for hydrogeological calibration less consistent. More advanced techniques such as coupled inversion allow for a direct use of geophysical data for conditioning groundwater and solute transport model calibration. However, the technique is difficult to apply in complex cases and remains computationally demanding to estimate uncertainty. In a recent study, we investigate a prediction-focused approach (PFA) to directly estimate subsurface physical properties from geophysical data, circumventing the need for classic inversions. In PFA, we seek a direct relationship between the data and the subsurface variables we want to predict (the forecast). This relationship is obtained through a prior set of subsurface models for which both data and forecast are computed. A direct relationship can often be derived through dimension reduction techniques. PFA offers a framework for both hydrogeophysical "inversion" and hydrogeophysical data integration. For hydrogeophysical "inversion", the considered forecast variable is the subsurface variable, such as the salinity. An ensemble of possible solutions is generated, allowing uncertainty quantification. For hydrogeophysical data integration, the forecast variable becomes the prediction we want to make with our subsurface models, such as the concentration of contaminant in a drinking water production well. Geophysical and hydrological data are combined to derive a direct relationship between data and forecast. We illustrate the process for the design of an aquifer thermal energy storage (ATES) system. An ATES system can theoretically recover in winter the heat stored in the aquifer during summer. In practice, the energy efficiency is often lower than expected due to spatial heterogeneity of hydraulic properties combined to a non-favorable hydrogeological gradient. A proper design of ATES systems should consider the uncertainty of the prediction related to those parameters. With a global sensitivity analysis, we identify sensitive parameters for heat storage prediction and validate the use of a short term heat tracing experiment monitored with geophysics to generate informative data. First, we illustrate how PFA can be used to successfully derive the distribution of temperature in the aquifer from ERT during the heat tracing experiment. Then, we successfully integrate the geophysical data to predict medium-term heat storage in the aquifer using PFA. The result is a full quantification of the posterior distribution of the prediction conditioned to observed data in a relatively limited time budget.

Optimal experimental design for placement of boreholes

NASA Astrophysics Data System (ADS)

Padalkina, Kateryna; Bücker, H. Martin; Seidler, Ralf; Rath, Volker; Marquart, Gabriele; Niederau, Jan; Herty, Michael

2014-05-01

Drilling for deep resources is an expensive endeavor. Among the many problems finding the optimal drilling location for boreholes is one of the challenging questions. We contribute to this discussion by using a simulation based assessment of possible future borehole locations. We study the problem of finding a new borehole location in a given geothermal reservoir in terms of a numerical optimization problem. In a geothermal reservoir the temporal and spatial distribution of temperature and hydraulic pressure may be simulated using the coupled differential equations for heat transport and mass and momentum conservation for Darcy flow. Within this model the permeability and thermal conductivity are dependent on the geological layers present in the subsurface model of the reservoir. In general, those values involve some uncertainty making it difficult to predict actual heat source in the ground. Within optimal experimental the question is which location and to which depth to drill the borehole in order to estimate conductivity and permeability with minimal uncertainty. We introduce a measure for computing the uncertainty based on simulations of the coupled differential equations. The measure is based on the Fisher information matrix of temperature data obtained through the simulations. We assume that the temperature data is available within the full borehole. A minimization of the measure representing the uncertainty in the unknown permeability and conductivity parameters is performed to determine the optimal borehole location. We present the theoretical framework as well as numerical results for several 2d subsurface models including up to six geological layers. Also, the effect of unknown layers on the introduced measure is studied. Finally, to obtain a more realistic estimate of optimal borehole locations, we couple the optimization to a cost model for deep drilling problems.

Evaluate the Relative Importance of Subsurface Lateral Energy Exchange to Ground Heat Flux and Energy Balance over the Heterogeneous Surface of a Sub-tropical Wetland

NASA Astrophysics Data System (ADS)

CUI, W.; Chui, T. F. M.

2016-12-01

Subsurface lateral water and energy exchanges are often ignored in methods involving a surface energy balance under the homogeneity assumption, which may affect the estimation of evapotranspiration over a heterogeneous surface. Wetlands, however, are heterogeneous with vegetated areas and open water, making it difficult to accurately measure and estimate evapotranspiration. This study estimated the subsurface lateral energy exchange between the reed bed and shallow open water of a wetland within Mai Po Nature Reserve in Hong Kong, and further discussed its relative importance to the ground heat flux and energy balance over the wetland surface. An array of water level and temperature sensors were installed in the reed bed and the adjacent water, together with an eddy covariance system. The results suggested that the lateral energy exchange was over 30% of ground heat flux for half of the monitoring period, and should therefore be accounted for during the measurement of ground heat flux. However, the lateral energy exchange could not explain the energy balance disclosure at the site, as the variation was in phase with the residual of energy budget during the summer but was out of phase during the winter. Furthermore, this study developed a convolution model to estimate the lateral energy exchange based on air temperature which is readily available at many sites worldwide. This study overall enhanced our understanding of the subsurface lateral energy exchange, and possibly our estimation of evapotranspiration in heterogeneous environment.

Shallow subsurface temperatures and some estimates of heat flow from the Colorado Plateau of northeastern Arizona

USGS Publications Warehouse

Sass, J.H.; Stone, Claudia; Bills, D.J.

1982-01-01

Temperature data to depths of a few hundred meters were obtained from 29 wells in northeastern Arizona; 12 in the region surrounding the San Francisco Volcanic Field, 8 in the Black Mesa area, and 9 in the south-central Colorado Plateau which includes the White Mountains. Although there was evidence for local hydrologic disturbances in many temperature profiles, most wells provided an estimate of the conductive thermal gradient at the site. A few thermal conductivities were measured and were combined with published regional averages for the north-central part of the Colorado Plateau to produce crude estimates of regional heat flux. None of the wells was accessible below the regional aquifers. To these depths, heat flow in the area of the San Francisco Volcanic Field appears to be controlled primarily by regional lateral water movement having a significant downward vertical component of velocity. The mean heat flow of 27?5 mW^-2 is only a third to a quarter of what we would expect in this tectonic setting. The heat that is being carried laterally and downward probably is being discharged at low enthalpy and low elevation in springs and streams of the Colorado Plateau and Mogollon Rim. In the vicinity of Black Mesa, heat-flow averages about 60 mW^-2, characteristic of the 'cool interior' of the Colorado Plateau. North of the White Mountain Volcanic Field, the average heat flow is about 95 mW^-2.

Ground-Coupled Heating-Cooling Systems in Urban Areas: How Sustainable Are They?

ERIC Educational Resources Information Center

Younger, Paul L.

2008-01-01

Ground-coupled heating-cooling systems (GCHCSs) exchange heat between the built environment and the subsurface using pipework buried in trenches or boreholes. If heat pumps in GCHCSs are powered by "green electricity," they offer genuine carbon-free heating-cooling; for this reason, there has been a surge in the technology in recent…

Novel approaches for an enhanced geothermal development of residential sites

NASA Astrophysics Data System (ADS)

Schelenz, Sophie; Firmbach, Linda; Shao, Haibing; Dietrich, Peter; Vienken, Thomas

2015-04-01

An ongoing technological enhancement drives an increasing use of shallow geothermal systems for heating and cooling applications. However, even in areas with intensive shallow geothermal use, planning of geothermal systems is in many cases solely based on geological maps, drilling databases, and literature references. Thus, relevant heat transport parameters are rather approximated than measured for the specific site. To increase the planning safety and promote the use of renewable energies in the domestic sector, this study investigates a novel concept for an enhanced geothermal development of residential neighbourhoods. This concept is based on a site-specific characterization of subsurface conditions and the implementation of demand-oriented geothermal usage options. Therefore, an investigation approach has been tested that combines non-invasive with minimum-invasive exploration methods. While electrical resistivity tomography has been applied to characterize the geological subsurface structure, Direct Push soundings enable a detailed, vertical high-resolution characterization of the subsurface surrounding the borehole heat exchangers. The benefit of this site-specific subsurface investigation is highlighted for 1) a more precise design of shallow geothermal systems and 2) a reliable prediction of induced long-term changes in groundwater temperatures. To guarantee the financial feasibility and practicability of the novel geothermal development, three different options for its implementation in residential neighbourhoods were consequently deduced.

Temperature change affected groundwater quality in a confined marine aquifer during long-term heating and cooling.

PubMed

Saito, Takeshi; Hamamoto, Shoichiro; Ueki, Takashi; Ohkubo, Satoshi; Moldrup, Per; Kawamoto, Ken; Komatsu, Toshiko

2016-05-01

Global warming and urbanization together with development of subsurface infrastructures (e.g. subways, shopping complexes, sewage systems, and Ground Source Heat Pump (GSHP) systems) will likely cause a rapid increase in the temperature of relatively shallow groundwater reservoirs (subsurface thermal pollution). However, potential effects of a subsurface temperature change on groundwater quality due to changed physical, chemical, and microbial processes have received little attention. We therefore investigated changes in 34 groundwater quality parameters during a 13-month enhanced-heating period, followed by 14 months of natural or enhanced cooling in a confined marine aquifer at around 17 m depth on the Saitama University campus, Japan. A full-scale GSHP test facility consisting of a 50 m deep U-tube for circulating the heat-carrying fluid and four monitoring wells at 1, 2, 5, and 10 m from the U-tube were installed, and groundwater quality was monitored every 1-2 weeks. Rapid changes in the groundwater level in the area, especially during the summer, prevented accurate analyses of temperature effects using a single-well time series. Instead, Dual-Well Analysis (DWA) was applied, comparing variations in subsurface temperature and groundwater chemical concentrations between the thermally-disturbed well and a non-affected reference well. Using the 1 m distant well (temperature increase up to 7 °C) and the 10 m distant well (non-temperature-affected), the DWA showed an approximately linear relationships for eight components (B, Si, Li, dissolved organic carbon (DOC), Mg(2+), NH4(+), Na(+), and K(+)) during the combined 27 months of heating and cooling, suggesting changes in concentration between 4% and 31% for a temperature change of 7 °C. Copyright © 2016 Elsevier Ltd. All rights reserved.

Subsurface flow recently triggered the development of taliks under a sub-Arctic road embankment: a prelude to the collapse of the Alaska Highway?

NASA Astrophysics Data System (ADS)

Chen, L.; Fortier, D.; Sliger, M.; McKenzie, J. M.; Murchison, P.

2017-12-01

The Alaska Highway extends over 2200 km between central Alaska, U.S.A. and northern British-Columbia, Canada. This transportation corridor is crucial for the economy of Alaska as it is the only terrestrial link between mainland Alaska and the contiguous United States. Northern British Columbia and southwestern Yukon also greatly benefit from this highway for the transportation of goods and people across this remote corner of Canada. About a quarter of the Alaska Highway is built on permafrost, which is typically ice-rich and at a temperature near the point of thawing. Degradation of the permafrost under the embankment has led to severe structural damages to the highway such as deep longitudinal cracks, extended depressions, potholes and sinkholes. Here we present thermal data from the Beaver Creek experimental road test section in southwestern Yukon. Our study investigates convective heat transfers linked to subsurface water flow under the road embankment based on seven years (2009 to 2016) of thermal monitoring. Observation results demonstrate that snowmelt water infiltration in the spring causes rapid temperature increase of the upper portion of the embankment. Later in the summer, subsurface flow under the highway embankment can lead to step temperature-increase rates, which can be 200 times larger than those via conductive heat transfers. In the fall water trapped under the road significantly delays freeze back of the active layer and contributes to higher permafrost temperature. During the monitoring period, we observed the initiation and growth of taliks along sub-surface flow paths. Positive feedback mechanisms related to water flow through the taliks significantly increased permafrost degradation. Such taliks represent an un-precedent and presumably irreversible thermal state of the highway. Similar terrain conditions which severely threaten the structural integrity of the infrastructure on the short term are numerous along the Alaska Highway corridor.

Characterization of the Long-term Subsurface Warming Observed at the Apollo 15 and 17 Sites Utilizing the Newly Restored Heat Flow Experiment Data from 1975 to 1977

NASA Astrophysics Data System (ADS)

Nagihara, S.; Kiefer, W. S.; Taylor, P. T.; Williams, D. R.; Nakamura, Y.; Krell, J. W.

2017-12-01

The Apollo Heat Flow Experiment (HFE) was conducted at landing sites 15 and 17 as part of the Apollo Lunar Surface Experiment Package (ALSEP) program. At each site, the astronauts drilled 2 holes, 10-m apart, and installed a probe in each. The probes monitored surface and subsurface temperatures. The Apollo 15 probes operated from July 1971 to January 1977. The Apollo 17 probes operated from December 1972 to September 1977. For both sites, only data from the beginning to December 1974 were archived previously. We have restored major portions of the 1975-1977 HFE data for both sites from two sets of sources recently recovered. One was the original ALSEP archival data tapes, from which raw HFE data were extracted and processed according to the procedure and the calibration data specified by the original investigators. The other was the ALSEP Performance Summary Reports, which included weekly logs of temperature readings from the deepest sensor of each of the probes. The original HFE investigators noted that temperature of the regolith well below the thermal skin depth ( 1 m) rose gradually through December 1974 at both sites. Possible causes of the warming have been debated since. The restored 1975-1977 HFE data allow more detailed characterization of this phenomenon, especially for the Apollo 17 site, for which the duration of data availability has more than doubled. For both sites, the subsurface warming continued till the end of observations. Simultaneously, thermal gradient decreased. Such behavior is consistent with one of the hypotheses proposed by the original investigators; temperature of the lunar surface around the probe increased by 2 to 4 K at the time of deployment. Consequently, the subsurface thermal regime gradually adjusted to the new boundary condition. The Lunar Reconnaissance Orbiter Camera images taken over the Apollo landing sites suggest that astronaut-induced surface disturbance resulted in lower albedo, and that should have raised average surface temperature. Other explanations may also be possible. For example, at the Apollo 15 site, it is known that radiation down the hole affected the upper section of the probe. In contrast, the Apollo 17 probes were installed with radiation shields at the top of the hole and at 0.3-m depth. Therefore, warming there is more likely to be conductive in nature.

Power systems utilizing the heat of produced formation fluid

DOEpatents

Lambirth, Gene Richard [Houston, TX

2011-01-11

Systems, methods, and heaters for treating a subsurface formation are described herein. At least one method includes treating a hydrocarbon containing formation. The method may include providing heat to the formation; producing heated fluid from the formation; and generating electricity from at least a portion of the heated fluid using a Kalina cycle.

3D structure and conductive thermal field of the Upper Rhine Graben

NASA Astrophysics Data System (ADS)

Freymark, Jessica; Sippel, Judith; Scheck-Wenderoth, Magdalena; Bär, Kristian; Stiller, Manfred; Fritsche, Johann-Gerhard; Kracht, Matthias

2016-04-01

The Upper Rhine Graben (URG) was formed as part of the European Cenozoic Rift System in a complex extensional setting. At present-day, it has a large socioeconomic relevance as it provides a great potential for geothermal energy production in Germany and France. For the utilisation of this energy resource it is crucial to understand the structure and the observed temperature anomalies in the rift basin. In the framework of the EU-funded "IMAGE" project (Integrated Methods for Advanced Geothermal Exploration), we apply a data-driven numerical modelling approach to quantify the processes and properties controlling the spatial distribution of subsurface temperatures. Typically, reservoir-scale numerical models are developed for predictions on the subsurface hydrothermal conditions and for reducing the risk of drilling non-productive geothermal wells. One major problem related to such models is setting appropriate boundary conditions that define, for instance, how much heat enters the reservoir from greater depths. Therefore, we first build a regional lithospheric-scale 3D structural model, which covers not only the entire URG but also adjacent geological features like the Black Forest and the Vosges Mountains. In particular, we use a multidisciplinary dataset (e.g. well data, seismic reflection data, existing structural models, gravity) to construct the geometries of the sediments, the crust and the lithospheric mantle that control the spatial distribution of thermal conductivity and radiogenic heat production and hence temperatures. By applying a data-based and lithology-dependent parameterisation of this lithospheric-scale 3D structural model and a 3D finite element method, we calculate the steady-state conductive thermal field for the entire region. Available measured temperatures (down to depths of up to 5 km) are considered to validate the 3D thermal model. We present major characteristics of the lithospheric-scale 3D structural model and results of the 3D conductive thermal modelling of the URG and adjacent areas. We show that the Variscan crystalline crustal domains with their different radiogenic heat production influence the regional thermal field, while a thermal blanketing effect due to thick thermally low-conductive sediments causes higher temperatures in the central and northern URG. In contrast, local salt domes result in colder temperatures in parts of the southern URG.

In situ methods for measuring thermal properties and heat flux on planetary bodies

PubMed Central

Kömle, Norbert I.; Hütter, Erika S.; Macher, Wolfgang; Kaufmann, Erika; Kargl, Günter; Knollenberg, Jörg; Grott, Matthias; Spohn, Tilman; Wawrzaszek, Roman; Banaszkiewicz, Marek; Seweryn, Karoly; Hagermann, Axel

2011-01-01

The thermo-mechanical properties of planetary surface and subsurface layers control to a high extent in which way a body interacts with its environment, in particular how it responds to solar irradiation and how it interacts with a potentially existing atmosphere. Furthermore, if the natural temperature profile over a certain depth can be measured in situ, this gives important information about the heat flux from the interior and thus about the thermal evolution of the body. Therefore, in most of the recent and planned planetary lander missions experiment packages for determining thermo-mechanical properties are part of the payload. Examples are the experiment MUPUS on Rosetta's comet lander Philae, the TECP instrument aboard NASA's Mars polar lander Phoenix, and the mole-type instrument HP3 currently developed for use on upcoming lunar and Mars missions. In this review we describe several methods applied for measuring thermal conductivity and heat flux and discuss the particular difficulties faced when these properties have to be measured in a low pressure and low temperature environment. We point out the abilities and disadvantages of the different instruments and outline the evaluation procedures necessary to extract reliable thermal conductivity and heat flux data from in situ measurements. PMID:21760643

Quantifying shallow subsurface water and heat dynamics using coupled hydrological-thermal-geophysical inversion

DOE PAGES

Tran, Anh Phuong; Dafflon, Baptiste; Hubbard, Susan S.; ...

2016-04-25

Improving our ability to estimate the parameters that control water and heat fluxes in the shallow subsurface is particularly important due to their strong control on recharge, evaporation and biogeochemical processes. The objectives of this study are to develop and test a new inversion scheme to simultaneously estimate subsurface hydrological, thermal and petrophysical parameters using hydrological, thermal and electrical resistivity tomography (ERT) data. The inversion scheme-which is based on a nonisothermal, multiphase hydrological model-provides the desired subsurface property estimates in high spatiotemporal resolution. A particularly novel aspect of the inversion scheme is the explicit incorporation of the dependence of themore » subsurface electrical resistivity on both moisture and temperature. The scheme was applied to synthetic case studies, as well as to real datasets that were autonomously collected at a biogeochemical field study site in Rifle, Colorado. At the Rifle site, the coupled hydrological-thermal-geophysical inversion approach well predicted the matric potential, temperature and apparent resistivity with the Nash-Sutcliffe efficiency criterion greater than 0.92. Synthetic studies found that neglecting the subsurface temperature variability, and its effect on the electrical resistivity in the hydrogeophysical inversion, may lead to an incorrect estimation of the hydrological parameters. The approach is expected to be especially useful for the increasing number of studies that are taking advantage of autonomously collected ERT and soil measurements to explore complex terrestrial system dynamics.« less

Numerical simulation of seasonal heat storage in a contaminated shallow aquifer - Temperature influence on flow, transport and reaction processes

NASA Astrophysics Data System (ADS)

Popp, Steffi; Beyer, Christof; Dahmke, Andreas; Bauer, Sebastian

2015-04-01

The energy market in Germany currently faces a rapid transition from nuclear power and fossil fuels towards an increased production of energy from renewable resources like wind or solar power. In this context, seasonal heat storage in the shallow subsurface is becoming more and more important, particularly in urban regions with high population densities and thus high energy and heat demand. Besides the effects of increased or decreased groundwater and sediment temperatures on local and large-scale groundwater flow, transport, geochemistry and microbiology, an influence on subsurface contaminations, which may be present in the urban surbsurface, can be expected. Currently, concerns about negative impacts of temperature changes on groundwater quality are the main barrier for the approval of heat storage at or close to contaminated sites. The possible impacts of heat storage on subsurface contamination, however, have not been investigated in detail yet. Therefore, this work investigates the effects of a shallow seasonal heat storage on subsurface groundwater flow, transport and reaction processes in the presence of an organic contamination using numerical scenario simulations. A shallow groundwater aquifer is assumed, which consists of Pleistoscene sandy sediments typical for Northern Germany. The seasonal heat storage in these scenarios is performed through arrays of borehole heat exchangers (BHE), where different setups with 6 and 72 BHE, and temperatures during storage between 2°C and 70°C are analyzed. The developing heat plume in the aquifer interacts with a residual phase of a trichloroethene (TCE) contamination. The plume of dissolved TCE emitted from this source zone is degraded by reductive dechlorination through microbes present in the aquifer, which degrade TCE under anaerobic redox conditions to the degradation products dichloroethene, vinyl chloride and ethene. The temperature dependence of the microbial degradation activity of each degradation step is taken into account for the numerical simulations. Hence, the simulations are performed with the code OpenGeoSys, which is especially suited for simulating coupled thermal, hydraulic and geochemical processes. The scenario simulations show an increase in the source zone emission of TCE at higher temperatures, which is primarily due to the focusing of the groundwater flow in the area of higher temperatures within the source zone and to a lesser part to an increase in TCE solubility. On the other hand, a widening of the contaminant plume and enlargement of the area for TCE biodegradation is induced, which leads to an increase in biodegradation of the chlorinated hydrocarbons. In combination almost no change in the overall ratio of degraded to emitted TCE is found, which shows that the seasonal heat storage is not negatively influencing the present TCE contamination under these assumptions. The results of this work serve to support the risk assessment for the interaction between heat storage and contaminations in the shallow subsurface and show positive interactions as well as possible conflicts.

Heat pulse probe measurements of soil water evaporation in a corn field

USDA-ARS?s Scientific Manuscript database

Latent heat fluxes from cropped fields consist of soil water evaporation and plant transpiration. It is difficult to accurately separate evapotranspiration into evaporation and transpiration. Heat pulse probes have been used to measure bare field subsurface soil water evaporation, however, the appl...

What on Mars is a High Thermal-Inertia Surface?

NASA Image and Video Library

2015-04-08

Coprates Chasma is located in the huge canyon system, Vallis Marineris. NASA Mars Reconnaissance Orbiter finds indications of high thermal inertia. What do we mean when we describe a surface as having "high thermal inertia"? The term refers to the ability of a material to conduct and store heat, and in planetary science, its measure of the subsurface's ability to store heat during the day and reradiate it during the night. What causes thermal inertia? It depends on the composition of the terrain that we're studying. Here in Coprates Chasma, the site of this observation, we find indications of such high thermal inertia, so an image at high resolution may help us determine the composition and structure to give us an answer. http://photojournal.jpl.nasa.gov/catalog/PIA19357

Time-varying Atmospheric Circulation Patterns Caused by N2 Condensation Flows on a Simulated Triton Atmosphere

NASA Astrophysics Data System (ADS)

Miller, C.; Chanover, N.; Murphy, J. R.; Zalucha, A. M.

2011-12-01

Triton and Pluto are two members of a possible class of bodies with an N2 frost covered surface in vapor-pressure equilibrium with a predominately N2 atmosphere. Modeling the dynamics of such an atmosphere is useful for several reasons. First, winds on Triton were inferred from images of surface streaks and active plumes visible at the time of the Voyager 2 flyby in August 1989. Dynamic atmospheric simulations can reveal the seasonal conditions under which such winds would arise and therefore how long before the Voyager 2 encounter the ground streaks may have been deposited. Second, atmospheric conditions on Pluto at the time of the New Horizons flyby are expected to be similar to those on Triton. Therefore, a dynamical model of a cold, thin N2 atmosphere can be used to predict wind speed and direction on Pluto during the New Horizons encounter with the Pluto/Charon system in July 2015. We used a modified version of the NASA Ames Mars General Circulation Model, version 2.0, to model an N2 atmosphere in contact with N2 surface frosts. We altered the Ames GCM to simulate conditions found on Triton. These alterations included changing the size, rotation rate, orbital inclination, surface gravity, and distance to the Sun of the parent body to model the proper time-varying insolation. We defined the gas properties for an N2 atmosphere, including values for latent heat, specific heat, and the vapor pressure-temperature relationship for N2 frosts. Our simulations assumed an N2 atmosphere with an initial average surface pressure of 18 microbars and we chose N2 frost albedo and emissivity values that resulted in a stable surface pressure over time. We incorporated a 190-meter deep ten-layer water-ice subsurface layer covered with a 20-centimeter global layer of N2 frost. Our simulations did not include atmospheric radiative heat transfer, but did include conduction, convection, and surface-boundary layer heating. We ran simulations of 100 Triton days at 10 points along Triton's orbit between the 1952 equinox and the 2000 southern summer solstice to examine seasonal changes in the condensation flow. We will present results from these simulations and discuss the interplay between sub-surface heat conduction, N2 frost phase changes, and atmospheric dynamics. We will also compare these results to those obtained under two other initial surface conditions - no N2 frost layer, and a global N2 frost layer with sublimation and condensation inhibited. These simulations provide a baseline for disentangling the respective roles of subsurface heating, local atmospheric mass change through surface frost sublimation and condensation, and the vapor pressure-temperature relationship for N2 frost. We will also present results of simulations incorporating a Newtonian thermal relaxation scheme with temperature-pressure profiles derived from a 2-D radiative-conductive model. Finally, we will compare our simulation results under conditions equivalent to those at the time of the Voyager 2 flyby to the wind field inferred by the pattern of ground streaks seen on Triton. This study was funded by a NASA Earth and Space Science Fellowship through grant number NNX09AQ96H.

Determination of thermal wave reflection coefficient to better estimate defect depth using pulsed thermography

NASA Astrophysics Data System (ADS)

Sirikham, Adisorn; Zhao, Yifan; Mehnen, Jörn

2017-11-01

Thermography is a promising method for detecting subsurface defects, but accurate measurement of defect depth is still a big challenge because thermographic signals are typically corrupted by imaging noise and affected by 3D heat conduction. Existing methods based on numerical models are susceptible to signal noise and methods based on analytical models require rigorous assumptions that usually cannot be satisfied in practical applications. This paper presents a new method to improve the measurement accuracy of subsurface defect depth through determining the thermal wave reflection coefficient directly from observed data that is usually assumed to be pre-known. This target is achieved through introducing a new heat transfer model that includes multiple physical parameters to better describe the observed thermal behaviour in pulsed thermographic inspection. Numerical simulations are used to evaluate the performance of the proposed method against four selected state-of-the-art methods. Results show that the accuracy of depth measurement has been improved up to 10% when noise level is high and thermal wave reflection coefficients is low. The feasibility of the proposed method in real data is also validated through a case study on characterising flat-bottom holes in carbon fibre reinforced polymer (CFRP) laminates which has a wide application in various sectors of industry.

In situ determination of heat flow in unconsolidated sediments

USGS Publications Warehouse

Sass, J.H.; Kennelly, J.P.; Wendt, W.E.; Moses, T.H.; Ziagos, J.P.

1979-01-01

Subsurface thermal measurements are the most effective, least ambiguous tools for identifying and delineating possible geothernml resources. Measurements of thermal gradient in the upper few tens of meters generally are sufficient to outline the major anomalies, but it is always desirable to combine these gradients with reliable estimates of thermal conductivity to provide data on the energy flux and to constrain models for the heat sources responsible for the observed, near-surface thermal anomalies. The major problems associated with heat-flow measurements in the geothermal exploration mode are concerned with the economics of casing and/or grouting holes, the repeated site visits necessary to obtain equilibrium temperature values, the possible legal liability associated with the disturbance of underground aquifers, the surface hazards presented by pipes protruding from the ground, and the security problems associated with leaving cased holes open for periods of weeks to months. We have developed a technique which provides reliable 'real-time' determinations of temperature, thermal conductivity, and hence, of heat flow during the drilling operation in unconsolidated sediments. A combined temperature, gradient, and thermal conductivity experiment can be carried out, by driving a thin probe through the bit about 1.5 meters into the formation in the time that would otherwise be required for a coring trip. Two or three such experiments over the depth range of, say, 50 to 150 meters provide a high-quality heat-flow determination at costs comparable to those associated with a standard cased 'gradient hole' to comparable depths. The hole can be backfilled and abandoned upon cessation of drilling, thereby eliminating the need for casing, grouting, or repeated site visits.

Usage of ensemble geothermal models to consider geological uncertainties

NASA Astrophysics Data System (ADS)

Rühaak, Wolfram; Steiner, Sarah; Welsch, Bastian; Sass, Ingo

2015-04-01

The usage of geothermal energy for instance by borehole heat exchangers (BHE) is a promising concept for a sustainable supply of heat for buildings. BHE are closed pipe systems, in which a fluid is circulating. Heat from the surrounding rocks is transferred to the fluid purely by conduction. The fluid carries the heat to the surface, where it can be utilized. Larger arrays of BHE require typically previous numerical models. Motivations are the design of the system (number and depth of the required BHE) but also regulatory reasons. Especially such regulatory operating permissions often require maximum realistic models. Although such realistic models are possible in many cases with today's codes and computer resources, they are often expensive in terms of time and effort. A particular problem is the knowledge about the accuracy of the achieved results. An issue, which is often neglected while dealing with highly complex models, is the quantification of parameter uncertainties as a consequence of the natural heterogeneity of the geological subsurface. Experience has shown, that these heterogeneities can lead to wrong forecasts. But also variations in the technical realization and especially of the operational parameters (which are mainly a consequence of the regional climate) can lead to strong variations in the simulation results. Instead of one very detailed single forecast model, it should be considered, to model numerous more simple models. By varying parameters, the presumed subsurface uncertainties, but also the uncertainties in the presumed operational parameters can be reflected. Finally not only one single result should be reported, but instead the range of possible solutions and their respective probabilities. In meteorology such an approach is well known as ensemble-modeling. The concept is demonstrated at a real world data set and discussed.

A numerical study of EGS heat extraction process based on a thermal non-equilibrium model for heat transfer in subsurface porous heat reservoir

NASA Astrophysics Data System (ADS)

Chen, Jiliang; Jiang, Fangming

2016-02-01

With a previously developed numerical model, we perform a detailed study of the heat extraction process in enhanced or engineered geothermal system (EGS). This model takes the EGS subsurface heat reservoir as an equivalent porous medium while it considers local thermal non-equilibrium between the rock matrix and the fluid flowing in the fractured rock mass. The application of local thermal non-equilibrium model highlights the temperature-difference heat exchange process occurring in EGS reservoirs, enabling a better understanding of the involved heat extraction process. The simulation results unravel the mechanism of preferential flow or short-circuit flow forming in homogeneously fractured reservoirs of different permeability values. EGS performance, e.g. production temperature and lifetime, is found to be tightly related to the flow pattern in the reservoir. Thermal compensation from rocks surrounding the reservoir contributes little heat to the heat transmission fluid if the operation time of an EGS is shorter than 15 years. We find as well the local thermal equilibrium model generally overestimates EGS performance and for an EGS with better heat exchange conditions in the heat reservoir, the heat extraction process acts more like the local thermal equilibrium process.

Cubic spline anchored grid pattern algorithm for high-resolution detection of subsurface cavities by the IR-CAT method

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

Kassab, A.J.; Pollard, J.E.

An algorithm is presented for the high-resolution detection of irregular-shaped subsurface cavities within irregular-shaped bodies by the IR-CAT method. The theoretical basis of the algorithm is rooted in the solution of an inverse geometric steady-state heat conduction problem. A Cauchy boundary condition is prescribed at the exposed surface, and the inverse geometric heat conduction problem is formulated by specifying the thermal condition at the inner cavities walls, whose unknown geometries are to be detected. The location of the inner cavities is initially estimated, and the domain boundaries are discretized. Linear boundary elements are used in conjunction with cubic splines formore » high resolution of the cavity walls. An anchored grid pattern (AGP) is established to constrain the cubic spline knots that control the inner cavity geometry to evolve along the AGP at each iterative step. A residual is defined measuring the difference between imposed and computed boundary conditions. A Newton-Raphson method with a Broyden update is used to automate the detection of inner cavity walls. During the iterative procedure, the movement of the inner cavity walls is restricted to physically realistic intermediate solutions. Numerical simulation demonstrates the superior resolution of the cubic spline AGP algorithm over the linear spline-based AGP in the detection of an irregular-shaped cavity. Numerical simulation is also used to test the sensitivity of the linear and cubic spline AGP algorithms by simulating bias and random error in measured surface temperature. The proposed AGP algorithm is shown to satisfactorily detect cavities with these simulated data.« less

Subsurface temperature estimation from climatology and satellite SST for the sea around Korean Peninsula 1Bong-Guk, Kim, 1Yang-Ki, Cho, 1Bong-Gwan, Kim, 1Young-Gi, Kim, 1Ji-Hoon, Jung 1School of Earth and Environmental Sciences, Seoul National University

NASA Astrophysics Data System (ADS)

Kim, Bong-Guk; Cho, Yang-Ki; Kim, Bong-Gwan; Kim, Young-Gi; Jung, Ji-Hoon

2015-04-01

Subsurface temperature plays an important role in determining heat contents in the upper ocean which are crucial in long-term and short-term weather systems. Furthermore, subsurface temperature affects significantly ocean ecology. In this study, a simple and practical algorithm has proposed. If we assume that subsurface temperature changes are proportional to surface heating or cooling, subsurface temperature at each depth (Sub_temp) can be estimated as follows PIC whereiis depth index, Clm_temp is temperature from climatology, dif0 is temperature difference between satellite and climatology in the surface, and ratio is ratio of temperature variability in each depth to surface temperature variability. Subsurface temperatures using this algorithm from climatology (WOA2013) and satellite SST (OSTIA) where calculated in the sea around Korean peninsula. Validation result with in-situ observation data show good agreement in the upper 50 m layer with RMSE (root mean square error) less than 2 K. The RMSE is smallest with less than 1 K in winter when surface mixed layer is thick, and largest with about 2~3 K in summer when surface mixed layer is shallow. The strong thermocline and large variability of the mixed layer depth might result in large RMSE in summer. Applying of mixed layer depth information for the algorithm may improve subsurface temperature estimation in summer. Spatial-temporal details on the improvement and its causes will be discussed.

Conceptual Model Evaluation using Advanced Parameter Estimation Techniques with Heat as a Tracer

NASA Astrophysics Data System (ADS)

Naranjo, R. C.; Morway, E. D.; Healy, R. W.

2016-12-01

Temperature measurements made at multiple depths beneath the sediment-water interface has proven useful for estimating seepage rates from surface-water channels and corresponding subsurface flow direction. Commonly, parsimonious zonal representations of the subsurface structure are defined a priori by interpretation of temperature envelopes, slug tests or analysis of soil cores. However, combining multiple observations into a single zone may limit the inverse model solution and does not take full advantage of the information content within the measured data. Further, simulating the correct thermal gradient, flow paths, and transient behavior of solutes may be biased by inadequacies in the spatial description of subsurface hydraulic properties. The use of pilot points in PEST offers a more sophisticated approach to estimate the structure of subsurface heterogeneity. This presentation evaluates seepage estimation in a cross-sectional model of a trapezoidal canal with intermittent flow representing four typical sedimentary environments. The recent improvements in heat as a tracer measurement techniques (i.e. multi-depth temperature probe) along with use of modern calibration techniques (i.e., pilot points) provides opportunities for improved calibration of flow models, and, subsequently, improved model predictions.

Subsurface Ocean Tides in Enceladus and Other Icy Moons

NASA Astrophysics Data System (ADS)

Beuthe, M.

2016-12-01

Could tidal dissipation within Enceladus' subsurface ocean account for the observed heat flow? Earthlike models of dynamical tides give no definitive answer because they neglect the influence of the crust. I propose here the first model of dissipative tides in a subsurface ocean, by combining the Laplace Tidal Equations with the membrane approach. For the first time, it is possible to compute tidal dissipation rates within the crust, ocean, and mantle in one go. I show that oceanic dissipation is strongly reduced by the crustal constraint, and thus contributes little to Enceladus' present heat budget. Tidal resonances could have played a role in a forming or freezing ocean less than 100 meters deep. The model is general: it applies to all icy satellites with a thin crust and a shallow or stratified ocean. Scaling rules relate the resonances and dissipation rate of a subsurface ocean to the ones of a surface ocean. If the ocean has low viscosity, the westward obliquity tide does not move the crust. Therefore, crustal dissipation due to dynamical obliquity tides can differ from the static prediction by up to a factor of two.

Application of the Quadrupole Method for Simulation of Passive Thermography

NASA Technical Reports Server (NTRS)

Winfree, William P.; Zalameda, Joseph N.; Gregory, Elizabeth D.

2017-01-01

Passive thermography has been shown to be an effective method for in-situ and real time nondestructive evaluation (NDE) to measure damage growth in a composite structure during cyclic loading. The heat generation by subsurface flaw results in a measurable thermal profile at the surface. This paper models the heat generation as a planar subsurface source and calculates the resultant temperature profile at the surface using a three dimensional quadrupole. The results of the model are compared to finite element simulations of the same planar sources and experimental data acquired during cyclic loading of composite specimens.

Reconstruction of the thermal environment evolution in urban areas from underground temperature distribution.

PubMed

Yamano, Makoto; Goto, Shusaku; Miyakoshi, Akinobu; Hamamoto, Hideki; Lubis, Rachmat Fajar; Monyrath, Vuthy; Taniguchi, Makoto

2009-04-15

It is possible to estimate the ground surface temperature (GST) history of the past several hundred years from temperature profiles measured in boreholes because the temporal variation in GST propagates into the subsurface by thermal diffusion. This "geothermal method" of reconstructing GST histories can be applied to studies of thermal environment evolution in urban areas, including the development of "heat islands." Temperatures in boreholes were logged at 102 sites in Bangkok, Jakarta, Taipei, Seoul and their surrounding areas in 2004 to 2007. The effects of recent surface warming can be recognized in the shapes of most of the obtained temperature profiles. The preliminary results of reconstruction of GST histories through inversion analysis show that GST increased significantly in the last century. Existing temperature profile data for the areas in and around Tokyo and Osaka can also be used to reconstruct GST histories. Because most of these cities are located on alluvial plains in relatively humid areas, it is necessary to use a model with groundwater flow and a layered subsurface structure for reconstruction analysis. Long-term records of subsurface temperatures at multiple depths may demonstrate how the GST variation propagates downward through formations. Time series data provide information on the mechanism of heat transfer (conduction or advection) and the thermal diffusivity. Long-term temperature monitoring has been carried out in a borehole located on the coast of Lake Biwa, Japan. Temperatures at 30 and 40 m below the ground surface were measured for 4 years and 2 years, respectively, with a resolution of 1 mK. The obtained records indicate steady increases at both depths with different rates, which is probably the result of some recent thermal event(s) near the surface. Borehole temperatures have also been monitored at selected sites in Bangkok, Jakarta, and Taiwan.

Thermal Methods for Investigating Ground-Water Recharge

USGS Publications Warehouse

Blasch, Kyle W.; Constantz, Jim; Stonestrom, David A.

2007-01-01

Recharge of aquifers within arid and semiarid environments is defined as the downward flux of water across the regional water table. The introduction of recharging water at the land surface can occur at discreet locations, such as in stream channels, or be distributed over the landscape, such as across broad interarroyo areas within an alluvial ground-water basin. The occurrence of recharge at discreet locations is referred to as focused recharge, whereas the occurrence of recharge over broad regions is referred to as diffuse recharge. The primary interest of this appendix is focused recharge, but regardless of the type of recharge, estimation of downward fluxes is essential to its quantification. Like chemical tracers, heat can come from natural sources or be intentionally introduced to infer transport properties and aquifer recharge. The admission and redistribution of heat from natural processes such as insolation, infiltration, and geothermal activity can be used to quantify subsurface flow regimes. Heat is well suited as a ground-water tracer because it provides a naturally present dynamic signal and is relatively harmless over a useful range of induced perturbations. Thermal methods have proven valuable for recharge investigations for several reasons. First, theoretical descriptions of coupled water-and-heat transport are available for the hydrologic processes most often encountered in practice. These include land-surface mechanisms such as radiant heating from the sun, radiant cooling into space, and evapotranspiration, in addition to the advective and conductive mechanisms that usually dominate at depth. Second, temperature is theoretically well defined and readily measured. Third, thermal methods for depths ranging from the land surface to depths of hundreds of meters are based on similar physical principles. Fourth, numerical codes for simulating heat and water transport have become increasingly reliable and widely available. Direct measurement of water flux in the subsurface is difficult, prompting investigators to pursue indirect methods. Geophysical approaches that exploit the coupled relation between heat and water transport provide an attractive class of methods that have become widely used in investigations of recharge. This appendix reviews the application of heat to the problem of recharge estimation. Its objective is to provide a fairly complete account of the theoretical underpinnings together with a comprehensive review of thermal methods in practice. Investigators began using subsurface temperatures to delineate recharge areas and infer directions of ground-water flow around the turn of the 20th century. During the 1960s, analytical and numerical solutions for simplified heat- and fluid-flow problems became available. These early solutions, though one-dimensional and otherwise restricted, provided a strong impetus for applying thermal methods to problems of liquid and vapor movement in systems ranging from soils to geothermal reservoirs. Today?s combination of fast processors, massive data-storage units, and efficient matrix techniques provide numerical solutions to complex, three-dimensional transport problems. These approaches allow researchers to take advantage of the considerable information content routinely achievable in high-accuracy temperature work.

Integrating Geohydrological Models In ATES-Systems Control

NASA Astrophysics Data System (ADS)

Bloemendal, Martin

2015-04-01

1) Purpose. Accomplish optimal and sustainable use of subsurface for Aquifer Thermal Energy Storage (ATES). 2) Scope. A heat pump in combination with an ATES system can efficiently and sustainably provide heating and cooling for user comfort within buildings. ATES systems are popular in moderate climate in which ATES systems are exploited as they are able to save primary energy. While storing warm and cold groundwater, ATES systems occupy a significant amount of the subsurface space, making that the space in the aquifers below cities is becoming scarce [1]. With the rapid growth of the number of ATES systems, the use of the subsurface intensifies, which raises additional questions regarding its sustainability and the long term profitability of the individual systems. In practice considerable difficulties regarding A) the performance of these installations and B) optimal and sustainable use of the subsurface are met. 3) Approach. Recently it was confirmed [2] that ATES systems can be placed closer to each other with limited effect on their energy efficiency. By placing them closer together we introduce the risk of a tragedy of the commons [3]. Therefore it is of importance to know where the warm and cold zones are over time and enable ATES-controllers to use the subsurface optimal and sustainably. From the field of multi agent systems and complex adaptive systems we use approaches and techniques to make an operation and control system that enables to adapt their control not only based on current demand, but also on current aquifer status and expected future demand. We are developing a numerical groundwater model structure which is fed with operational data of different ATES-systems. While doing this we run into challenges and opportunities like; spatial and temporal scale issues, sustaining the storage with balancing thermal storage and extraction at area level, dynamics and relation between hydrological and thermal influence and consequences for spreading of contaminants, using thermal energy storage for "peak-shaving" of wind/solar power production etc.. I will address the following two topics; - Balancing of stored heating and cooling capacity. To sustain an ATES-system heating and cooling capacity storage must more or less balance. Buildings often do not have a similar heating and cooling demand. Placing ATES-well closer to each other offers the opportunity to exchange energy between different buildings in the subsurface to balance heating and cooling capacity. To be able to do so, thorough understanding of the interaction between thermal influence area resulting from highly dynamic and uncertain energy demand from buildings is required. - The hydrological influence area of ATES wells is much bigger than the thermal influence area. Placing wells closer to each other therefor has a significant effect on the mixing of water and spreading of contaminants (which are often present in shallow aquifers under (old) city centers). We use both analytical and numerical approaches to gain insight in patterns of thermal and contaminant spreading and to find solutions in managing these effects. 4) Results and conclusions The subsurface is of crucial importance for intended energy savings. A control system working towards a global optimum for both the subsurface and buildings, instead of a local optimum for an individual building and local ATES will increase the overall efficiency. What is needed for that is insight in the spatial temperature distribution in the subsurface, in combination with adaptive and robust operational rules. We want to prove that a groundwater model simulating active ATES-systems can provide insight in the subsurface temperature distribution to adjust their control strategy in accordance with up-to-date information. Step by step we are solving the problems on this path, I would like to share and discuss my results, solutions and challenges. References [1] Bloemendal, M., Olsthoorn, T., Boons, F., How to achieve optimal and sustainable use of the subsurface for Aquifer Thermal Energy Storage, Energy Policy 66(2014) 104-114 [2] Sommer, W., Valstar, J., Leusbrock, I., Grotenhuis, T., Rijnaarts, H., Optimization and spatial pattern of large-scale aquifer thermal energy storage, Applied Energy 137 (2015) 322-337 [3] Hardin, G., The tragedy of the commons, Science162 (168) 12-13.

Groundwater flow with energy transport and water-ice phase change: Numerical simulations, benchmarks, and application to freezing in peat bogs

USGS Publications Warehouse

McKenzie, J.M.; Voss, C.I.; Siegel, D.I.

2007-01-01

In northern peatlands, subsurface ice formation is an important process that can control heat transport, groundwater flow, and biological activity. Temperature was measured over one and a half years in a vertical profile in the Red Lake Bog, Minnesota. To successfully simulate the transport of heat within the peat profile, the U.S. Geological Survey's SUTRA computer code was modified. The modified code simulates fully saturated, coupled porewater-energy transport, with freezing and melting porewater, and includes proportional heat capacity and thermal conductivity of water and ice, decreasing matrix permeability due to ice formation, and latent heat. The model is verified by correctly simulating the Lunardini analytical solution for ice formation in a porous medium with a mixed ice-water zone. The modified SUTRA model correctly simulates the temperature and ice distributions in the peat bog. Two possible benchmark problems for groundwater and energy transport with ice formation and melting are proposed that may be used by other researchers for code comparison. ?? 2006 Elsevier Ltd. All rights reserved.

Defining the Post-Machined Sub-surface in Austenitic Stainless Steels

NASA Astrophysics Data System (ADS)

Srinivasan, N.; Sunil Kumar, B.; Kain, V.; Birbilis, N.; Joshi, S. S.; Sivaprasad, P. V.; Chai, G.; Durgaprasad, A.; Bhattacharya, S.; Samajdar, I.

2018-04-01

Austenitic stainless steels grades, with differences in chemistry, stacking fault energy, and thermal conductivity, were subjected to vertical milling. Anodic potentiodynamic polarization was able to differentiate (with machining speed/strain rate) between different post-machined sub-surfaces in SS 316L and Alloy A (a Cu containing austenitic stainless steel: Sanicroe 28™), but not in SS 304L. However, such differences (in the post-machined sub-surfaces) were revealed in surface roughness, sub-surface residual stresses and misorientations, and in the relative presence of sub-surface Cr2O3 films. It was shown, quantitatively, that higher machining speed reduced surface roughness and also reduced the effective depths of the affected sub-surface layers. A qualitative explanation on the sub-surface microstructural developments was provided based on the temperature-dependent thermal conductivity values. The results herein represent a mechanistic understanding to rationalize the corrosion performance of widely adopted engineering alloys.

Defining the Post-Machined Sub-surface in Austenitic Stainless Steels

NASA Astrophysics Data System (ADS)

Srinivasan, N.; Sunil Kumar, B.; Kain, V.; Birbilis, N.; Joshi, S. S.; Sivaprasad, P. V.; Chai, G.; Durgaprasad, A.; Bhattacharya, S.; Samajdar, I.

2018-06-01

Austenitic stainless steels grades, with differences in chemistry, stacking fault energy, and thermal conductivity, were subjected to vertical milling. Anodic potentiodynamic polarization was able to differentiate (with machining speed/strain rate) between different post-machined sub-surfaces in SS 316L and Alloy A (a Cu containing austenitic stainless steel: Sanicroe 28™), but not in SS 304L. However, such differences (in the post-machined sub-surfaces) were revealed in surface roughness, sub-surface residual stresses and misorientations, and in the relative presence of sub-surface Cr2O3 films. It was shown, quantitatively, that higher machining speed reduced surface roughness and also reduced the effective depths of the affected sub-surface layers. A qualitative explanation on the sub-surface microstructural developments was provided based on the temperature-dependent thermal conductivity values. The results herein represent a mechanistic understanding to rationalize the corrosion performance of widely adopted engineering alloys.

The effects of orbital and climatic variations on Martian surface heat flow

NASA Technical Reports Server (NTRS)

Mellon, Michael T.; Jakosky, Bruce M.

1993-01-01

Large changes in the orbital elements of Mars on timescales of 10(exp 4) to 10(exp 6) years will cause widely varying climate, specifically surface temperatures, as a result of varying insolation. These surface temperature oscillations will produce subsurface thermal gradients which contribute to the total surface heat flux. We investigate the thermal behavior of the Martian regolith on orbital timescales and show that this climatological surface heat flux is spatially variable and contributes significantly to the total surface heat flux at many locations. We model the thermal behavior of the Martian regolith by calculating the mean annual surface temperatures for each epoch (spaced 1000 years apart to resolve orbital variations) for the past 200,000 years at a chosen location on the surface. These temperatures are used as a boundary condition for the deeper regolith and subsurface temperature oscillation are then computed. The surface climatological heat flux due to past climate changes can then be found from the temperature gradient between the surface and about 150 m depth (a fraction of the thermal skin depth on these timescales). This method provides a fairly accurate determination of the climatological heat flow component at a point; however, this method is computationally time consuming and cannot be applied to all points on the globe. To map the spatial variations in the surface heat flow we recognize that the subsurface temperature structure will be largely dominated by the most recent surface temperature oscillations. In fact, the climate component of the surface heat flow will be approximately proportional to the magnitude of the most recent surface temperature change. By calculating surface temperatures at all points globally for the present epoch and an appropriate past epoch, and combining these results with a series of more precise calculations described above, we estimate the global distribution of climatological surface heat flow.

Reconciling different observations of the CO2 ice mass loading of the Martian north polar cap

USGS Publications Warehouse

Haberle, R.M.; Mattingly, B.; Titus, T.N.

2004-01-01

The GRS measurements of the peak mass loading of the north polar CO2 ice cap on Mars are about 60% lower than those calculated from MGS TES radiation data and those inferred from the MOLA cap thicknesses. However, the GRS data provide the most accurate measurement of the mass loading. We show that the TES and MOLA data can be reconciled with the GRS data if (1) subsurface heat conduction and atmospheric heat transport are included in the TES mass budget calculations, and (2) the density of the polar deposits is ???600 kg m-3. The latter is much less than that expected for slab ice (???1600 kg m-3) and suggests that processes unique to the north polar region are responsible for the low cap density. Copyright 2004 by the American Geophysical Union.

Nano-Localized Thermal Analysis and Mapping of Surface and Sub-Surface Thermal Properties Using Scanning Thermal Microscopy (SThM).

PubMed

Pereira, Maria J; Amaral, Joao S; Silva, Nuno J O; Amaral, Vitor S

2016-12-01

Determining and acting on thermo-physical properties at the nanoscale is essential for understanding/managing heat distribution in micro/nanostructured materials and miniaturized devices. Adequate thermal nano-characterization techniques are required to address thermal issues compromising device performance. Scanning thermal microscopy (SThM) is a probing and acting technique based on atomic force microscopy using a nano-probe designed to act as a thermometer and resistive heater, achieving high spatial resolution. Enabling direct observation and mapping of thermal properties such as thermal conductivity, SThM is becoming a powerful tool with a critical role in several fields, from material science to device thermal management. We present an overview of the different thermal probes, followed by the contribution of SThM in three currently significant research topics. First, in thermal conductivity contrast studies of graphene monolayers deposited on different substrates, SThM proves itself a reliable technique to clarify the intriguing thermal properties of graphene, which is considered an important contributor to improve the performance of downscaled devices and materials. Second, SThM's ability to perform sub-surface imaging is highlighted by thermal conductivity contrast analysis of polymeric composites. Finally, an approach to induce and study local structural transitions in ferromagnetic shape memory alloy Ni-Mn-Ga thin films using localized nano-thermal analysis is presented.

Cometary activity and nucleus modelling: a new approach

NASA Astrophysics Data System (ADS)

Möhlmann, D.

1996-06-01

The phenomena of comet splittings with an average frequency of about one splitting per 100 years and comet (Chen and Jewitt, Icarus108, 265-271, 1994), and the restriction of cometary activity to well-defined small areas at the almost passive and mantle covered surface (Keller et al., ESA SP-250, Vol. II, pp. 363-364, 1986) are at present driving challenges to models of structure and evolution of comet nuclei. Extending the presently discussed models by incorporating lateral subsurface transport of sublimed volatiles, there appears the possibility that the places of sublimation are different from those of activity (the so-called active areas). Then, there is no necessity to distinguish between different surface properties at active and passive areas, assuming, e.g. an uncovered icy surface at active areas. Active areas are simply the very local "source sites" where the accumulated subsurface flows from distant regions reach the surface. The pressure driven subsurface flows of volatiles may not only leave the comet at its surface, they may penetrate via cracks, etc. also deeply into the nucleus. There they can cause a further growth of cracks and also new cracks. This can be a cause for the observed regular splittings. Furthermore, actual models (Kührt and Keller, Icarus109, 121-132, 1994; Skorov and Rickman, Planet. Space Sci.43, 1587-1594, 1995) of the gas transport through porous comet surface crusts can be interpreted as to give first indications for thermodynamical parameters in heat conducting and porous cometary crusts which are appropriate for 1 AU conditions to permit the temporary existence of a layer with fluid subsurface water within these crusts. This exciting result of the possible temporary existence of subsurface warm water in comets which approach the Sun within about 1 AU makes a cometary subsurface chemistry much more efficient than expected hitherto.

Numerical evaluation of a sensible heat balance method to determine rates of soil freezing and thawing

USDA-ARS?s Scientific Manuscript database

In-situ determination of ice formation and thawing in soils is difficult despite its importance for many environmental processes. A sensible heat balance (SHB) method using a sequence of heat pulse probes has been shown to accurately measure water evaporation in subsurface soil, and it has the poten...

Direct thermal effects of the Hadean bombardment did not limit early subsurface habitability

NASA Astrophysics Data System (ADS)

Grimm, R. E.; Marchi, S.

2018-03-01

Intense bombardment is considered characteristic of the Hadean and early Archean eons, yet some detrital zircons indicate that near-surface water was present and thus at least intervals of clement conditions may have existed. We investigate the habitability of the top few kilometers of the subsurface by updating a prior approach to thermal evolution of the crust due to impact heating, using a revised bombardment history, a more accurate thermal model, and treatment of melt sheets from large projectiles (>100 km diameter). We find that subsurface habitable volume grows nearly continuously throughout the Hadean and early Archean (4.5-3.5 Ga) because impact heat is dissipated rapidly compared to the total duration and waning strength of the bombardment. Global sterilization was only achieved using an order of magnitude more projectiles in 1/10 the time. Melt sheets from large projectiles can completely resurface the Earth several times prior to ∼4.2 Ga but at most once since then. Even in the Hadean, melt sheets have little effect on habitability because cooling times are short compared to resurfacing intervals, allowing subsurface biospheres to be locally re-established by groundwater infiltration between major impacts. Therefore the subsurface is always habitable somewhere, and production of global steam or silicate-vapor atmospheres are the only remaining avenues to early surface sterilization by bombardment.

Sustainable intensive thermal use of the shallow subsurface-a critical view on the status quo.

PubMed

Vienken, T; Schelenz, S; Rink, K; Dietrich, P

2015-01-01

Thermal use of the shallow subsurface for heat generation, cooling, and thermal energy storage is increasingly gaining importance in reconsideration of future energy supplies. Shallow geothermal energy use is often promoted as being of little or no costs during operation, while simultaneously being environmentally friendly. Hence, the number of installed systems has rapidly risen over the last few decades, especially among newly built houses. While the carbon dioxide reduction potential of this method remains undoubted, concerns about sustainability and potential negative effects on the soil and groundwater due to an intensified use have been raised-even as far back as 25 years ago. Nevertheless, consistent regulation and management schemes for the intensified thermal use of the shallow subsurface are still missing-mainly due to a lack of system understanding and process knowledge. In the meantime, large geothermal applications, for example, residential neighborhoods that are entirely dependent up on shallow geothermal energy use or low enthalpy aquifer heat storage, have been developed throughout Europe. Potential negative effects on the soil and groundwater due to an intensive thermal use of the shallow subsurface as well as the extent of potential system interaction still remain unknown. © 2014, National Ground Water Association.

Subsurface warming across the Veluwe area (Netherlands) driven by climate change, urbanisation, groundwater abstraction and aquifer energy storage

NASA Astrophysics Data System (ADS)

Bense, Victor; de Kleijn, Christian; van Daal, Jonathan

2017-04-01

Atmospheric warming, urbanisation, land-use changes, groundwater abstraction and aquifer thermal energy storage can induce significant changes in the subsurface thermal regime. These need to better understood and monitored in order for humanity to make efficient use of the subsurface as a thermal reservoir, but also to understand how this space acts as a heat sink during the current warming of the climate. This work aims to improve our understanding of the relative importance, spatiotemporal characteristics and mechanisms of how various environmental processes and anthropogenic activities control changes in subsurface thermal regimes. Such changes are poignantly illustrated by temperature-depth profiles recently obtained in 30 boreholes upto several hundreds of meters deep that are present in the unconsolidated sedimentary aquifer system of the Veluwe area, Netherlands. A comparison to similar data collected in 1978-1980 shows that since then across the entire study area subsurface warming has occurred to depths upto 250 m. The availability of historic land-use maps, hydrogeological and meteorological data for this area allow for a detailed analysis of the observed subsurface warming patterns, which is aided by numerical models of coupled groundwater and heat flow. On a regional scale and across the entire first 100-150 m into the subsurface, the classic thermal signatures of variations in land-use, groundwater recharge and discharge fluxes, are increasingly overprinted by those of regional atmospheric warming and urbanisation. In the topographically higher, forested groundwater recharge areas groundwater is significantly cooler (upto 6 K) than in the open agricultural lands where groundwater is discharging. The presence of a thick (upto 30-40 m) unsaturated zone in the recharge area probably enhances this striking contrast in groundwater temperature in addition to the effects of groundwater recharge and the presence of forest. Locally and at larger depths, however, aquifer thermal storage activities and groundwater abstraction have a strong and probably more immediate role in altering the subsurface thermal regime.

Development of monitoring and modelling tools as basis for sustainable thermal management concepts of urban groundwater bodies

NASA Astrophysics Data System (ADS)

Mueller, Matthias H.; Epting, Jannis; Köhler, Mandy; Händel, Falk; Huggenberger, Peter

2015-04-01

Increasing groundwater temperatures observed in many urban areas strongly interfere with the demand of thermal groundwater use. The groundwater temperatures in these urban areas are affected by numerous interacting factors: open and closed-loop geothermal systems for heating and cooling, sealed surfaces, constructions in the subsurface (infrastructure and buildings), artificial groundwater recharge, and interaction with rivers. On the one hand, these increasing groundwater temperatures will negatively affect the potential for its use in the future e.g. for cooling purposes. On the other hand, elevated subsurface temperatures can be considered as an energy source for shallow geothermal heating systems. Integrated thermal management concepts are therefore needed to coordinate the thermal use of groundwater in urban areas. These concepts should be based on knowledge of the driving processes which influence the thermal regime of the aquifer. We are currently investigating the processes influencing the groundwater temperature throughout the urban area of Basel City, Switzerland. This involves a three-dimensional numerical groundwater heat-transport model including geothermal use and interactions with the unsaturated zone such as subsurface constructions reaching into the aquifer. The cantonal groundwater monitoring system is an important part of the data base in our model, which will help to develop sustainable management strategies. However, single temperature measurements in conventional groundwater wells can be biased by vertical thermal convection. Therefore, multilevel observation wells are used in the urban areas of the city to monitor subsurface temperatures reaching from the unsaturated zone to the base of the aquifer. These multilevel wells are distributed in a pilot area in order to monitor the subsurface temperatures in the vicinity of deep buildings and to quantify the influence of the geothermal use of groundwater. Based on time series of the conventional groundwater wells, the multilevel observation wells and the different boundary conditions we characterize the groundwater temperature regimes using a regional groundwater heat-transport model. In the urban area of Basel, mean annual groundwater temperatures are significantly increasing with 0.05 K per year in the period of 1994 to 2014, which is most likely due to anthropogenic influences. Overall, mean annual groundwater temperatures of Basel are 3.0

Characterization of Magma-Driven Hydrothermal Systems at Oceanic Spreading Centers

NASA Astrophysics Data System (ADS)

Farough, A.; Lowell, R. P.; Corrigan, R.

2012-12-01

Fluid circulation in high-temperature hydrothermal systems involves complex water-rock chemical reactions and phase separation. Numerical modeling of reactive transport in multi-component, multiphase systems is required to obtain a full understanding of the characteristics and evolution of hydrothermal vent systems. We use a single-pass parameterized model of high-temperature hydrothermal circulation at oceanic spreading centers constrained by observational parameters such as vent temperature, heat output, and vent field area, together with surface area and depth of the sub-axial magma chamber, to deduce fundamental hydrothermal parameters such as mass flow rate, bulk permeability, conductive boundary layer thickness at the base of the system, magma replenishment rate, and residence time in the discharge zone. All of these key subsurface characteristics are known for fewer than 10 sites out of 300 known hydrothermal systems. The principal limitations of this approach stem from the uncertainty in heat output and vent field area. For systems where data are available on partitioning of heat and chemical output between focused and diffuse flow, we determined the fraction of high-temperature vent fluid incorporated into diffuse flow using a two-limb single pass model. For EPR 9°50` N and ASHES, the diffuse flow temperatures calculated assuming conservative mixing are nearly equal to the observed temperatures indicating that approximately 80%-90% of the hydrothermal heat output occurs as high-temperature flow derived from magmatic heat even though most of the heat output appears as low-temperature diffuse discharge. For the Main Endeavour Field and Lucky Strike, diffuse flow fluids show significant conductive cooling and heating respectively. Finally, we calculate the transport of various geochemical constituents in focused and diffuse flow at the vent field scale and compare the results with estimates of geochemical transports from the Rainbow hydrothermal field where diffuse flow is absent.

Heat Flux and Wall Temperature Estimates for the NASA Langley HIFiRE Direct Connect Rig

NASA Technical Reports Server (NTRS)

Cuda, Vincent, Jr.; Hass, Neal E.

2010-01-01

An objective of the Hypersonic International Flight Research Experimentation (HIFiRE) Program Flight 2 is to provide validation data for high enthalpy scramjet prediction tools through a single flight test and accompanying ground tests of the HIFiRE Direct Connect Rig (HDCR) tested in the NASA LaRC Arc Heated Scramjet Test Facility (AHSTF). The HDCR is a full-scale, copper heat sink structure designed to simulate the isolator entrance conditions and isolator, pilot, and combustor section of the HIFiRE flight test experiment flowpath and is fully instrumented to assess combustion performance over a range of operating conditions simulating flight from Mach 5.5 to 8.5 and for various fueling schemes. As part of the instrumentation package, temperature and heat flux sensors were provided along the flowpath surface and also imbedded in the structure. The purpose of this paper is to demonstrate that the surface heat flux and wall temperature of the Zirconia coated copper wall can be obtained with a water-cooled heat flux gage and a sub-surface temperature measurement. An algorithm was developed which used these two measurements to reconstruct the surface conditions along the flowpath. Determinations of the surface conditions of the Zirconia coating were conducted for a variety of conditions.

Optimization of Borehole Thermal Energy Storage System Design Using Comprehensive Coupled Simulation Models

NASA Astrophysics Data System (ADS)

Welsch, Bastian; Rühaak, Wolfram; Schulte, Daniel O.; Formhals, Julian; Bär, Kristian; Sass, Ingo

2017-04-01

Large-scale borehole thermal energy storage (BTES) is a promising technology in the development of sustainable, renewable and low-emission district heating concepts. Such systems consist of several components and assemblies like the borehole heat exchangers (BHE), other heat sources (e.g. solarthermics, combined heat and power plants, peak load boilers, heat pumps), distribution networks and heating installations. The complexity of these systems necessitates numerical simulations in the design and planning phase. Generally, the subsurface components are simulated separately from the above ground components of the district heating system. However, as fluid and heat are exchanged, the subsystems interact with each other and thereby mutually affect their performances. For a proper design of the overall system, it is therefore imperative to take into account the interdependencies of the subsystems. Based on a TCP/IP communication we have developed an interface for the coupling of a simulation package for heating installations with a finite element software for the modeling of the heat flow in the subsurface and the underground installations. This allows for a co-simulation of all system components, whereby the interaction of the different subsystems is considered. Furthermore, the concept allows for a mathematical optimization of the components and the operational parameters. Consequently, a finer adjustment of the system can be ensured and a more precise prognosis of the system's performance can be realized.

Ground-Atmosphere Interactions at Gale: Determination of the Surface Energy Budget, Thermal Inertia and Water Sorption on the Regolith

NASA Astrophysics Data System (ADS)

Martinez, German; Renno, Nilton; Fischer, Erik; Borlina, Caue; Hallet, Bernard; De la Torre Juarez, Manuel; Vasavada, Aswhin; Gomez-Elvira, Javier

2014-05-01

The analysis of the Surface Energy Budget (SEB) yields insights into the local climate and the soil-atmosphere interactions, while the analysis of the thermal inertia of the shallow subsurface augments surface observations, providing information about the local geology. The Mars Global Surveyor Thermal Emission Spectrometer and the Mars Odyssey Thermal Emission Imaging System have measured near subsurface thermal inertia from orbit at scales of ~104 m2 to ~10 km2. Here we report analysis of the thermal inertia at a few locations at Gale Crater at scales of 100 m2. The thermal inertia is calculated by solving the heat conduction equation in the soil using hourly measurements by the Rover Environmental Station (REMS) ground temperature sensor as an upper boundary condition. Three Sols representative of different environmental conditions and soil properties, namely, Sol 82 at Rocknest (RCK), Sol 112 at Point Lake (PL) and Sol 139 at Yellowknife Bay (YKB) are analyzed in detail. The largest thermal inertia (I) value is found at YKB, I = 445 J m-2 K-1 s-1/2 or 445 tiu (thermal inertia unit), followed by PL with I= 300 tiu and RCK withI = 280 tiu [1]. These values are consistent with the type of terrain imaged by MastCam and with previous satellite estimates at Gale Crater [2,3]. The SEB is calculated by using all REMS data products as well as dust opacity values derived from MastCam measurements, whereas previously, the SEB has been calculated using numerical models only [4]. At each location and during the daytime, the SEB is dominated by the downwelling shortwave (SW) solar radiation (~450-500 W/m2) and the upwelling longwave (LW) radiation emitted by the surface (~300-400 W/m2). The sum of these two terms accounts for at least 70% of the net surface heating rate between 0900 and 1400 local solar time. At nighttime, the SEB is dominated by the upwelling LW radiation emitted by the surface (~50-100 W/m2) and the downwelling LW radiation from the atmosphere (~50 W/m2). When the wind speeds exceed 10 m/s at night, the turbulent heat flux can be as large as 25 W/m2, thus playing a secondary but significant role in the SEB. Finally, we estimate the amount of adsorbed water exchanged between the shallow subsurface and the atmosphere at diurnal time scales. We use subsurface temperature profiles, obtained by solving the heat conduction equation in the soil using the calculated value of I, and adsorption and desorption isotherms [5] to analyze critically the correlation between the soil wetness measured by the Dynamic Albedo of Neutrons instrument and the relative humidity measured by REMS. Acknowledgement: This research is supported by a grant from the Mars Science Laboratory and NASA Astrobiology Program Award #09-EXOB09-0050. References: [1] Martinez, G.M. et al. (2014), JGR (submitted). [2] Pelkey, S. M., and B. M. Jakosky (2002), doi:10.1006/icar.2002.6978. [3] Fergason, R., P. et al. (2012), doi:10.1007/s11214-012-9891-3. [4] Savijärvi, H., and A. Määttänen (2010), doi:10.1002/qj.650. [5] Pommerol, A. et al. (2009), doi:10.1016/j.icarus.2009.06.013.

Fiber Optic Bragg Grating Sensors for Thermographic Detection of Subsurface Anomalies

NASA Technical Reports Server (NTRS)

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

2009-01-01

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

Modeling the Martian seasonal CO2 cycle. I - Fitting the Viking Lander pressure curves. II - Interannual variability

NASA Technical Reports Server (NTRS)

Wood, Stephen E.; Paige, David A.

1992-01-01

The present diurnal and seasonal thermal model for Mars, in which surface CO2 frost condensation and sublimation are determined by the net effects of radiation, latent heat, and heat conduction in subsurface soil layers, in order to simulate seasonal exchanges of CO2 between the polar caps and atmosphere, successfully reproduces the measured pressured variations at the Viking Lander 1 site. In the second part of this work, the year-to-year differences between measured surface pressures at Viking sites as a function of season are used as upper limits on the potential magnitudes of interannual variations in the Martian atmosphere's mass. Simulations indicate that the dust layers deposited onto the condensing north seasonal polar cap during dust storms can darken seasonal frost deposits upon their springtime uncovering, while having little effect on seasonal pressure variations.

CO2 cycle

USGS Publications Warehouse

Titus, Timothy N.; Byrne, Shane; Colaprete, Anthony; Forget, Francois; Michaels, Timothy I.; Prettyman, Thomas H.

2017-01-01

This chapter discusses the use of models, observations, and laboratory experiments to understand the cycling of CO2 between the atmosphere and seasonal Martian polar caps. This cycle is primarily controlled by the polar heat budget, and thus the emphasis here is on its components, including solar and infrared radiation, the effect of clouds (water- and CO2-ice), atmospheric transport, and subsurface heat conduction. There is a discussion about cap properties including growth and regression rates, albedos and emissivities, grain sizes and dust and/or water-ice contamination, and curious features like cold gas jets and araneiform (spider-shaped) terrain. The nature of the residual south polar cap is discussed as well as its long-term stability and ability to buffer atmospheric pressures. There is also a discussion of the consequences of the CO2 cycle as revealed by the non-condensable gas enrichment observed by Odyssey and modeled by various groups.

Using electrical impedance tomography to map subsurface hydraulic conductivity

DOEpatents

Berryman, James G.; Daily, William D.; Ramirez, Abelardo L.; Roberts, Jeffery J.

2000-01-01

The use of Electrical Impedance Tomography (EIT) to map subsurface hydraulic conductivity. EIT can be used to map hydraulic conductivity in the subsurface where measurements of both amplitude and phase are made. Hydraulic conductivity depends on at least two parameters: porosity and a length scale parameter. Electrical Resistance Tomography (ERT) measures and maps electrical conductivity (which can be related to porosity) in three dimensions. By introducing phase measurements along with amplitude, the desired additional measurement of a pertinent length scale can be achieved. Hydraulic conductivity controls the ability to flush unwanted fluid contaminants from the surface. Thus inexpensive maps of hydraulic conductivity would improve planning strategies for subsequent remediation efforts. Fluid permeability is also of importance for oil field exploitation and thus detailed knowledge of fluid permeability distribution in three-dimension (3-D) would be a great boon to petroleum reservoir analysts.

Using Actively Heated Fibre Optics (AHFO) to determine soil thermal conductivity and soil moisture content at high spatial and temporal resolution

NASA Astrophysics Data System (ADS)

Ciocca, Francesco; Abesser, Corinna; Hannah, David; Blaen, Philip; Chalari, Athena; Mondanos, Michael; Krause, Stefan

2017-04-01

Optical fibre distributed temperature sensing (DTS) is increasingly used in environmental monitoring and for subsurface characterisation, e.g. to obtain precise measurements of soil temperature at high spatio-temporal resolution, over several kilometres of optical fibre cable. When combined with active heating of metal elements embedded in the optical fibre cable (active-DTS), the temperature response of the soil to heating provides valuable information from which other important soil parameters, such as thermal conductivity and soil moisture content, can be inferred. In this presentation, we report the development of an Actively Heated Fibre Optics (AHFO) method for the characterisation of soil thermal conductivity and soil moisture dynamics at high temporal and spatial resolutions at a vegetated hillslope site in central England. The study site is located within a juvenile forest adjacent to the Birmingham Institute of Forest Research (BIFoR) experimental site. It is instrumented with three loops of a 500m hybrid-optical cable installed at 10cm, 25cm and 40cm depths. Active DTS surveys were undertaken in June and October 2016, collecting soil temperature data at 0.25m intervals along the cable, prior to, during and after the 900s heating phase. Soil thermal conductivity and soil moisture were determined according to Ciocca et al. 2012, applied to both the cooling and the heating phase. Independent measurements of soil thermal conductivity and soil moisture content were collected using thermal needle probes, calibrated capacitance-based probes and laboratory methods. Results from both the active DTS survey and independent in-situ and laboratory measurements will be presented, including the observed relationship between thermal conductivity and moisture content at the study site and how it compares against theoretical curves used by the AHFO methods. The spatial variability of soil thermal conductivity and soil moisture content, as observed using the different methods, will be shown and an outlook will be provided of how the AHFO method can benefit soil sciences, ground source heat pump applications and groundwater recharge estimations. This research is part of the Distributed intelligent Heat Pulse System (DiHPS) project which is funded by the UK Natural Environmental Research Council (NERC). The project is supported by BIFoR, the European Space Agency (ESA), CarbonZero Ltd, the UK Forestry Commission and the UK Soil Moisture Observation Network (COSMOS-UK). This work is distributed under the Creative Commons Attribution 3.0 Unported Licence together with an author copyright. This licence does not conflict with the regulations of the Crown Copyright. Ciocca F., Lunati I., van de Giesen N., and Parlange M.B. 2012. Heated optical fiber for distributed soil-moisture measurements: A lysimeter experiment. Vadose Zone J. 11. doi:10.2136/vzj2011.0177

Large temporal scale and capacity subsurface bulk energy storage with CO2

NASA Astrophysics Data System (ADS)

Saar, M. O.; Fleming, M. R.; Adams, B. M.; Ogland-Hand, J.; Nelson, E. S.; Randolph, J.; Sioshansi, R.; Kuehn, T. H.; Buscheck, T. A.; Bielicki, J. M.

2017-12-01

Decarbonizing energy systems by increasing the penetration of variable renewable energy (VRE) technologies requires efficient and short- to long-term energy storage. Very large amounts of energy can be stored in the subsurface as heat and/or pressure energy in order to provide both short- and long-term (seasonal) storage, depending on the implementation. This energy storage approach can be quite efficient, especially where geothermal energy is naturally added to the system. Here, we present subsurface heat and/or pressure energy storage with supercritical carbon dioxide (CO2) and discuss the system's efficiency, deployment options, as well as its advantages and disadvantages, compared to several other energy storage options. CO2-based subsurface bulk energy storage has the potential to be particularly efficient and large-scale, both temporally (i.e., seasonal) and spatially. The latter refers to the amount of energy that can be stored underground, using CO2, at a geologically conducive location, potentially enabling storing excess power from a substantial portion of the power grid. The implication is that it would be possible to employ centralized energy storage for (a substantial part of) the power grid, where the geology enables CO2-based bulk subsurface energy storage, whereas the VRE technologies (solar, wind) are located on that same power grid, where (solar, wind) conditions are ideal. However, this may require reinforcing the power grid's transmission lines in certain parts of the grid to enable high-load power transmission from/to a few locations.

Some Ecological Mechanisms to Generate Habitability in Planetary Subsurface Areas by Chemolithotrophic Communities: The Ro Tinto Subsurface Ecosystem as a Model System

NASA Astrophysics Data System (ADS)

Fernández-Remolar, David C.; Gómez, Felipe; Prieto-Ballesteros, Olga; Schelble, Rachel T.; Rodríguez, Nuria; Amiols, Ricardo

2008-02-01

Chemolithotrophic communities that colonize subsurface habitats have great relevance for the astrobiological exploration of our Solar System. We hypothesize that the chemical and thermal stabilization of an environment through microbial activity could make a given planetary region habitable. The MARTE project ground-truth drilling campaigns that sampled cryptic subsurface microbial communities in the basement of the Ro Tinto headwaters have shown that acidic surficial habitats are the result of the microbial oxidation of pyritic ores. The oxidation process is exothermic and releases heat under both aerobic and anaerobic conditions. These microbial communities can maintain the subsurface habitat temperature through storage heat if the subsurface temperature does not exceed their maximum growth temperature. In the acidic solutions of the Ro Tinto, ferric iron acts as an effective buffer for controlling water pH. Under anaerobic conditions, ferric iron is the oxidant used by microbes to decompose pyrite through the production of sulfate, ferrous iron, and protons. The integration between the physical and chemical processes mediated by microorganisms with those driven by the local geology and hydrology have led us to hypothesize that thermal and chemical regulation mechanisms exist in this environment and that these homeostatic mechanisms could play an essential role in creating habitable areas for other types of microorganisms. Therefore, searching for the physicochemical expression of extinct and extant homeostatic mechanisms through physical and chemical anomalies in the Mars crust (i.e., local thermal gradient or high concentration of unusual products such as ferric sulfates precipitated out from acidic solutions produced by hypothetical microbial communities) could be a first step in the search for biological traces of a putative extant or extinct Mars biosphere.

Some ecological mechanisms to generate habitability in planetary subsurface areas by chemolithotrophic communities: the Río Tinto subsurface ecosystem as a model system.

PubMed

Fernández-Remolar, David C; Gómez, Felipe; Prieto-Ballesteros, Olga; Schelble, Rachel T; Rodríguez, Nuria; Amils, Ricardo

2008-02-01

Chemolithotrophic communities that colonize subsurface habitats have great relevance for the astrobiological exploration of our Solar System. We hypothesize that the chemical and thermal stabilization of an environment through microbial activity could make a given planetary region habitable. The MARTE project ground-truth drilling campaigns that sampled cryptic subsurface microbial communities in the basement of the Río Tinto headwaters have shown that acidic surficial habitats are the result of the microbial oxidation of pyritic ores. The oxidation process is exothermic and releases heat under both aerobic and anaerobic conditions. These microbial communities can maintain the subsurface habitat temperature through storage heat if the subsurface temperature does not exceed their maximum growth temperature. In the acidic solutions of the Río Tinto, ferric iron acts as an effective buffer for controlling water pH. Under anaerobic conditions, ferric iron is the oxidant used by microbes to decompose pyrite through the production of sulfate, ferrous iron, and protons. The integration between the physical and chemical processes mediated by microorganisms with those driven by the local geology and hydrology have led us to hypothesize that thermal and chemical regulation mechanisms exist in this environment and that these homeostatic mechanisms could play an essential role in creating habitable areas for other types of microorganisms. Therefore, searching for the physicochemical expression of extinct and extant homeostatic mechanisms through physical and chemical anomalies in the Mars crust (i.e., local thermal gradient or high concentration of unusual products such as ferric sulfates precipitated out from acidic solutions produced by hypothetical microbial communities) could be a first step in the search for biological traces of a putative extant or extinct Mars biosphere.

Small scale changes of geochemistry and flow field due to transient heat storage in aquifers

NASA Astrophysics Data System (ADS)

Bauer, S.; Boockmeyer, A.; Li, D.; Beyer, C.

2013-12-01

Heat exchangers in the subsurface are increasingly installed for transient heat storage due to the need of heating or cooling of buildings as well as the interim storage of heat to compensate for the temporally fluctuating energy production by wind or solar energy. For heat storage to be efficient, high temperatures must be achieved in the subsurface. Significant temporal changes of the soil and groundwater temperatures however effect both the local flow field by temperature dependent fluid parameters as well as reactive mass transport through temperature dependent diffusion coefficients, geochemical reaction rates and mineral equilibria. As the use of heat storage will be concentrated in urban areas, the use of the subsurface for (drinking) water supply and heat storage will typically coincide and a reliable prognosis of the processes occurring is needed. In the present work, the effects of a temporal variation of the groundwater temperature, as induced by a local heat exchanger introduced into a groundwater aquifer, are studied. For this purpose, the coupled non-isothermal groundwater flow, heat transport and reactive mass transport is simulated in the near filed of such a heat exchanger. By explicitly discretizing and incorporating the borehole, the borehole cementation and the heat exchanger tubes, a realistic geometrical and process representation is obtained. The numerical simulation code OpenGeoSys is used in this work, which incorporates the required processes of coupled groundwater flow, heat and mass transport as well as temperature dependent geochemistry. Due to the use of a Finite Element Method, a close representation of the geometric effects can be achieved. Synthetic scenario simulations for typical settings of salt water formations in northern Germany are used to investigate the geochemical effects arising from a high temperature heat storage by quantifying changes in groundwater chemistry and overall reaction rates. This work presents the simulation approach used and results obtained for the synthetic scenarios. The model simulations show that locally in the direct vicinity of the borehole heat exchanger the flow field is changed, causing a ground water convergence and thus a mixing of water in the case of high temperatures. Also, geochemical reactions are induced due to shifting of temperature dependent mineral equilibria. Due to the moving groundwater, the changes are not reversible, and small impacts remain downstream of the borehole heat exchanger. However, the changes depend strongly on the mineral composition of the formation and the formation water present.

Heat as a tracer to estimate dissolved organic carbon flux from a restored wetland

USGS Publications Warehouse

Burow, K.R.; Constantz, J.; Fujii, R.

2005-01-01

Heat was used as a natural tracer to characterize shallow ground water flow beneath a complex wetland system. Hydrogeologic data were combined with measured vertical temperature profiles to constrain a series of two-dimensional, transient simulations of ground water flow and heat transport using the model code SUTRA (Voss 1990). The measured seasonal temperature signal reached depths of 2.7 m beneath the pond. Hydraulic conductivity was varied in each of the layers in the model in a systematic manual calibration of the two-dimensional model to obtain the best fit to the measured temperature and hydraulic head. Results of a series of representative best-fit simulations represent a range in hydraulic conductivity values that had the best agreement between simulated and observed temperatures and that resulted in simulated pond seepage values within 1 order of magnitude of pond seepage estimated from the water budget. Resulting estimates of ground water discharge to an adjacent agricultural drainage ditch were used to estimate potential dissolved organic carbon (DOC) loads resulting from the restored wetland. Estimated DOC loads ranged from 45 to 1340 g C/(m2 year), which is higher than estimated DOC loads from surface water. In spite of the complexity in characterizing ground water flow in peat soils, using heat as a tracer provided a constrained estimate of subsurface flow from the pond to the agricultural drainage ditch. Copyright ?? 2005 National Ground Water Association.

Evolution of Heat Flow with Age on the Southern Flank of the Costa Rica Rift

NASA Astrophysics Data System (ADS)

Kolandaivelu, K. P.; Harris, R. N.; Lowell, R. P.; Wilson, D. J.; Hobbs, R. W.

2017-12-01

Analysis of 67 new conductive heat flow measurements at five sites ranging between ≈ 1.6 and 5.7 Ma on the southern flank of the Costa Rica Rift yields insight into factors that influence hydrothermal circulation in young oceanic crust. The heat flow measurements were collocated with a high-resolution multi-channel seismic line, extending from the ridge axis to ODP hole 504B. The mean conductive heat flow, qobs, 80 mWm-2, is ≈ 25% of the mean lithospheric heat flux, qth, predicted by half-space conductive cooling model. The ratio qobs/qth varies significantly from site to site indicating that advective heat loss may be influenced by the presence of high-angle, ridge-ward dipping normal faults, surface topography, and sediment thickness, which vary significantly along the profile. The 1.6 Ma heat flow site, which is located between two outcrops separated by 2 km and has thin sediment cover, yields qobs/qth » 0.08. The advective heat loss indicates a mass flux of 3 x 10-5 kgm-2s-1 and upper crustal permeabilities of 4 x 10-11 and 3 x 10-9 m2 for 1000 m and 100 m aquifer thicknesses, respectively. At the 2.6 Ma site with 75 m sediment cover, qobs/qth » 0.18 and heat flow is uniformly low, except for one high value near a fault. At the 3.5 Ma site, qobs/qth » 0.15. The heat flow deficit results from outcrop to outcrop flow, but subcritical cellular convection driven by local basement topography produces small heat flow highs and lows superimposed on the overall trend. At the 4.5 Ma site, qobs/qth » 0.06. The heat flow distribution indicates that discharge occurs through a large, thinly-sedimented topographical high, where estimated mass flux is 3 x 10-5 kgm-2s-1. At the oldest site of 5.7 Ma, qobs/qth » 1, but some heat flow values greater than qth occur near sparsely-sedimented basement outcrops, suggesting redistribution of heat by subsurface convection controlled by basement topography, similar to ODP Hole 504B. That qobs/qth » 1 at a much younger age than indicated by global data suggests that basement burial under a thick sediment cover inhibits advective heat loss through the crust. These data were collected as part of a major interdisciplinary NERC and NSF-funded collaboration entitled: Oceanographic and Seismic Characterization of heat dissipation and alteration by hydrothermal fluids at an Axial Ridge (OSCAR).

Quantifying the processes controlling intraseasonal mixed-layer temperature variability in the tropical Indian Ocean

NASA Astrophysics Data System (ADS)

Halkides, D. J.; Waliser, Duane E.; Lee, Tong; Menemenlis, Dimitris; Guan, Bin

2015-02-01

Spatial and temporal variation of processes that determine ocean mixed-layer (ML) temperature (MLT) variability on the timescale of the Madden-Julian Oscillation (MJO) in the Tropical Indian Ocean (TIO) are examined in a heat-conserving ocean state estimate for years 1993-2011. We introduce a new metric for representing spatial variability of the relative importance of processes. In general, horizontal advection is most important at the Equator. Subsurface processes and surface heat flux are more important away from the Equator, with surface heat flux being the more dominant factor. Analyses at key sites are discussed in the context of local dynamics and literature. At 0°, 80.5°E, for MLT events > 2 standard deviations, ocean dynamics account for more than two thirds of the net tendency during cooling and warming phases. Zonal advection alone accounts for ˜40% of the net tendency. Moderate events (1-2 standard deviations) show more differences between events, and some are dominated by surface heat flux. At 8°S, 67°E in the Seychelles-Chagos Thermocline Ridge (SCTR) area, surface heat flux accounts for ˜70% of the tendency during strong cooling and warming phases; subsurface processes linked to ML depth (MLD) deepening (shoaling) during cooling (warming) account for ˜30%. MLT is more sensitive to subsurface processes in the SCTR, due to the thin MLD, thin barrier layer and raised thermocline. Results for 8°S, 67°E support assertions by Vialard et al. (2008) not previously confirmed due to measurement error that prevented budget closure and the small number of events studied. The roles of MLD, barrier layer thickness, and thermocline depth on different timescales are examined.

Sequential cryogen spraying for heat flux control at the skin surface

NASA Astrophysics Data System (ADS)

Majaron, Boris; Aguilar, Guillermo; Basinger, Brooke; Randeberg, Lise L.; Svaasand, Lars O.; Lavernia, Enrique J.; Nelson, J. Stuart

2001-05-01

Heat transfer rate at the skin-air interface is of critical importance for the benefits of cryogen spray cooling in combination with laser therapy of shallow subsurface skin lesions, such as port-wine stain birthmarks. With some cryogen spray devices, a layer of liquid cryogen builds up on the skin surface during the spurt, which may impair heat transfer across the skin surface due to relatively low thermal conductivity and potentially higher temperature of the liquid cryogen layer as compared to the spray droplets. While the mass flux of cryogen delivery can be adjusted by varying the atomizing nozzle geometry, this may strongly affect other spray properties, such as lateral spread (cone), droplet size, velocity, and temperature distribution. We present here first experiments with sequential cryogen spraying, which may enable accurate mass flux control through variation of spray duty cycle, while minimally affecting other spray characteristics. The observed increase of cooling rate and efficiency at moderate duty cycle levels supports the above described hypothesis of isolating liquid layer, and demonstrates a novel approach to optimization of cryogen spray devices for individual laser dermatological applications.

Basin-scale geothermal model calibration: experience from the Perth Basin, Australia

NASA Astrophysics Data System (ADS)

Wellmann, Florian; Reid, Lynn

2014-05-01

The calibration of large-scale geothermal models for entire sedimentary basins is challenging as direct measurements of rock properties and subsurface temperatures are commonly scarce and the basal boundary conditions poorly constrained. Instead of the often applied "trial-and-error" manual model calibration, we examine here if we can gain additional insight into parameter sensitivities and model uncertainty with a model analysis and calibration study. Our geothermal model is based on a high-resolution full 3-D geological model, covering an area of more than 100,000 square kilometers and extending to a depth of 55 kilometers. The model contains all major faults (>80 ) and geological units (13) for the entire basin. This geological model is discretised into a rectilinear mesh with a lateral resolution of 500 x 500 m, and a variable resolution at depth. The highest resolution of 25 m is applied to a depth range of 1000-3000 m where most temperature measurements are available. The entire discretised model consists of approximately 50 million cells. The top thermal boundary condition is derived from surface temperature measurements on land and ocean floor. The base of the model extents below the Moho, and we apply the heat flux over the Moho as a basal heat flux boundary condition. Rock properties (thermal conductivity, porosity, and heat production) have been compiled from several existing data sets. The conductive geothermal forward simulation is performed with SHEMAT, and we then use the stand-alone capabilities of iTOUGH2 for sensitivity analysis and model calibration. Simulated temperatures are compared to 130 quality weighted bottom hole temperature measurements. The sensitivity analysis provided a clear insight into the most sensitive parameters and parameter correlations. This proved to be of value as strong correlations, for example between basal heat flux and heat production in deep geological units, can significantly influence the model calibration procedure. The calibration resulted in a better determination of subsurface temperatures, and, in addition, provided an insight into model quality. Furthermore, a detailed analysis of the measurements used for calibration highlighted potential outliers, and limitations with the model assumptions. Extending the previously existing large-scale geothermal simulation with iTOUGH2 provided us with a valuable insight into the sensitive parameters and data in the model, which would clearly not be possible with a simple trial-and-error calibration method. Using the gained knowledge, future work will include more detailed studies on the influence of advection and convection.

Methods of producing transportation fuel

DOEpatents

Nair, Vijay [Katy, TX; Roes, Augustinus Wilhelmus Maria [Houston, TX; Cherrillo, Ralph Anthony [Houston, TX; Bauldreay, Joanna M [Chester, GB

2011-12-27

Systems, methods, and heaters for treating a subsurface formation are described herein. At least one method for producing transportation fuel is described herein. The method for producing transportation fuel may include providing formation fluid having a boiling range distribution between -5.degree. C. and 350.degree. C. from a subsurface in situ heat treatment process to a subsurface treatment facility. A liquid stream may be separated from the formation fluid. The separated liquid stream may be hydrotreated and then distilled to produce a distilled stream having a boiling range distribution between 150.degree. C. and 350.degree. C. The distilled liquid stream may be combined with one or more additives to produce transportation fuel.

3D modeling of groundwater heat transport in the shallow Westliches Leibnitzer Feld aquifer, Austria

NASA Astrophysics Data System (ADS)

Rock, Gerhard; Kupfersberger, Hans

2018-02-01

For the shallow Westliches Leibnitzer feld aquifer (45 km2) we applied the recently developed methodology by Kupfersberger et al. (2017a) to derive the thermal upper boundary for a 3D heat transport model from observed air temperatures. We distinguished between land uses of grass and agriculture, sealed surfaces, forest and water bodies. To represent the heat flux from heated buildings and the mixture between different land surfaces in urban areas we ran the 1D vertical heat conduction module SoilTemp which is coupled to the heat transport model (using FEFLOW) on a time step basis. Over a simulation period of 23 years the comparison between measured and observed groundwater temperatures yielded NSE values ranging from 0.41 to 0.92 including readings at different depths. The model results showed that the thermal input signals lead to distinctly different vertical groundwater temperature distributions. To overcome the influence of specific warm or cold years we introduced the computation of an annual averaged groundwater temperature profile. With respect to the use of groundwater cooling or heating facilities we evaluated the application of vertically averaged statistical groundwater temperature distributions compared to the use of temperature distributions at selected dates. We concluded that the heat transport model serves well as an aquifer scale management tool to optimize the use of the shallow subsurface for thermal purposes and to analyze the impacts of corresponding measures on groundwater temperatures.

The contribution of geology and groundwater studies to city-scale ground heat network strategies: A case study from Cardiff, UK

NASA Astrophysics Data System (ADS)

Boon, David; Farr, Gareth; Patton, Ashley; Kendall, Rhian; James, Laura; Abesser, Corinna; Busby, Jonathan; Schofield, David; White, Debbie; Gooddy, Daren; James, David; Williams, Bernie; Tucker, David; Knowles, Steve; Harcombe, Gareth

2016-04-01

The development of integrated heat network strategies involving exploitation of the shallow subsurface requires knowledge of ground conditions at the feasibility stage, and throughout the life of the system. We describe an approach to the assessment of ground constraints and energy opportunities in data-rich urban areas. Geological and hydrogeological investigations have formed a core component of the strategy development for sustainable thermal use of the subsurface in Cardiff, UK. We present findings from a 12 month project titled 'Ground Heat Network at a City Scale', which was co-funded by NERC/BGS and the UK Government through the InnovateUK Energy Catalyst grant in 2015-16. The project examined the technical feasibility of extracting low grade waste heat from a shallow gravel aquifer using a cluster of open loop ground source heat pumps. Heat demand mapping was carried out separately. The ground condition assessment approach involved the following steps: (1) city-wide baseline groundwater temperature mapping in 2014 with seasonal monitoring for at least 12 months prior to heat pump installation (Patton et al 2015); (2) desk top and field-based investigation of the aquifer system to determine groundwater levels, likely flow directions, sustainable pumping yields, water chemistry, and boundary conditions; (3) creation of a 3D geological framework model with physical property testing and model attribution; (4) use steps 1-3 to develop conceptual ground models and production of maps and GIS data layers to support scenario planning, and initial heat network concept designs; (5) heat flow modelling in FEFLOW software to analyse sustainability and predict potential thermal breakthrough in higher risk areas; (6) installation of a shallow open loop GSHP research observatory with real-time monitoring of groundwater bodies to provide data for heat flow model validation and feedback for system control. In conclusion, early ground condition modelling and subsurface monitoring have provided an initial indication of ground constraints and opportunities supporting development of aquifer thermal energy systems in Cardiff. Ground models should consider the past and future anthropogenic processes that influence and modify the condition of the ground. These include heat losses from buildings, modification of the groundwater regime by artificial pumping, sewers, and other GSH schemes, and construction hazards such as buried infrastructure, old foundations, land contamination and un-exploded ordnance. This knowledge base forms the foundation for a 'whole life' approach for sustainable thermal use of the subsurface. Benefits of the approach include; timely and easy to understand information for land use and financial resource planning, reduced financial risk for developers and investors, clear evidence to help improve public perception of GSHP technology, and provision of independent environmental data to satisfy the needs of the regulator. References: Patton, A.M., Farr, G.J., Boon, D.P., James, D.R., Williams, B., Newell, A.J. 2015. Shallow Groundwater Temperatures and the Urban Heat Island Effect: the First U.K City-wide Geothermal Map to Support Development of Ground Source Heating Systems Strategy. Geophysical Research Abstracts. EGU 2015 Vienna, Austria. (Poster)

Subsurface North Atlantic warming as a trigger of rapid cooling events: evidences from the Early Pleistocene (MIS 31-19)

NASA Astrophysics Data System (ADS)

Hernández-Almeida, I.; Sierro, F.-J.; Cacho, I.; Flores, J.-A.

2014-10-01

Subsurface water column dynamics in the subpolar North Atlantic were reconstructed in order to improve the understanding of the cause of abrupt IRD events during cold periods of the Early Pleistocene. We used Mg / Ca-based temperatures of deep-dwelling (Neogloboquadrina pachyderma sinistral) planktonic foraminifera and paired Mg / Ca-δ18O measurements to estimate the subsurface temperatures and δ18O of seawater at Site U1314. Carbon isotopes on benthic and planktonic foraminifera from the same site provide information about the ventilation and water column nutrient gradient. Mg / Ca-based temperatures and δ18O of seawater suggest increased temperatures and salinities during ice-rafting, likely due to enhanced northward subsurface transport of subtropical waters during periods of AMOC reduction. Planktonic carbon isotopes support this suggestion, showing coincident increased subsurface ventilation during deposition of ice-rafted detritus (IRD). Warm waters accumulated at subsurface would result in basal warming and break-up of ice-shelves, leading to massive iceberg discharges in the North Atlantic. Release of heat and salt stored at subsurface would help to restart the AMOC. This mechanism is in agreement with modelling and proxy studies that observe a subsurface warming in the North Atlantic in response to AMOC slowdown during the MIS3.

Subsurface damage detection in non-ferrous systems using 3D synchronous magnetic inspection

NASA Astrophysics Data System (ADS)

Gray, David; Berry, David

2018-04-01

Prime Photonics is developing a non-destructive inspection (NDI) technology, 3-D synchronous magnetic imaging system (3-D SMIS), that uses synchronous detection of magnetic signatures resulting from ultrasonic excitation to measure both surface and subsurface flaws in conductive structures. 3-D SMIS is showing promise in a wide range of NDI/NDE uses including characterizing surface-breaking cracks in ferrous and non-ferrous materials, locating and characterizing subsurface cracks within nonferrous conductive materials (Ti 6-4 and carbon fiber composites), and characterization of subsurface residual stresses. The technology offers a non-contact, high resolution inspection technique that does not require austere environments, and can accommodate non-planar specimen geometries.

Subsurface North Atlantic warming as a trigger of rapid cooling events: evidence from the early Pleistocene (MIS 31-19)

NASA Astrophysics Data System (ADS)

Hernández-Almeida, I.; Sierro, F.-J.; Cacho, I.; Flores, J.-A.

2015-04-01

Subsurface water column dynamics in the subpolar North Atlantic were reconstructed in order to improve the understanding of the cause of abrupt ice-rafted detritus (IRD) events during cold periods of the early Pleistocene. We used paired Mg / Ca and δ18O measurements of Neogloboquadrina pachyderma (sinistral - sin.), deep-dwelling planktonic foraminifera, to estimate the subsurface temperatures and seawater δ18O from a sediment core from Gardar Drift, in the subpolar North Atlantic. Carbon isotopes of benthic and planktonic foraminifera from the same site provide information about the ventilation and water column nutrient gradient. Mg / Ca-based temperatures and seawater δ18O suggest increased subsurface temperatures and salinities during ice-rafting, likely due to northward subsurface transport of subtropical waters during periods of weaker Atlantic Meridional Overturning Circulation (AMOC). Planktonic carbon isotopes support this suggestion, showing coincident increased subsurface ventilation during deposition of IRD. Subsurface accumulation of warm waters would have resulted in basal warming and break-up of ice-shelves, leading to massive iceberg discharges in the North Atlantic. The release of heat stored at the subsurface to the atmosphere would have helped to restart the AMOC. This mechanism is in agreement with modelling and proxy studies that observe a subsurface warming in the North Atlantic in response to AMOC slowdown during Marine Isotope Stage (MIS) 3.

Development of concepts for the management of thermal resources in urban areas - Assessment of transferability from the Basel (Switzerland) and Zaragoza (Spain) case studies

NASA Astrophysics Data System (ADS)

Epting, Jannis; García-Gil, Alejandro; Huggenberger, Peter; Vázquez-Suñe, Enric; Mueller, Matthias H.

2017-05-01

The shallow subsurface in urban areas is increasingly used by shallow geothermal energy systems as a renewable energy resource and as a cheap cooling medium, e.g. for building air conditioning. In combination with further anthropogenic activities, this results in altered thermal regimes in the subsurface and the so-called subsurface urban heat island effect. Successful thermal management of urban groundwater resources requires understanding the relative contributions of the different thermal parameters and boundary conditions that result in the "present thermal state" of individual urban groundwater bodies. To evaluate the "present thermal state" of urban groundwater bodies, good quality data are required to characterize the hydraulic and thermal aquifer parameters. This process also involved adequate monitoring systems which provide consistent subsurface temperature measurements and are the basis for parameterizing numerical heat-transport models. This study is based on previous work already published for two urban groundwater bodies in Basel (CH) and Zaragoza (ES), where comprehensive monitoring networks (hydraulics and temperature) as well as calibrated high-resolution numerical flow- and heat-transport models have been analyzed. The "present thermal state" and how it developed according to the different hydraulic and thermal boundary conditions is compared to a "potential natural state" in order to assess the anthropogenic thermal changes that have already occurred in the urban groundwater bodies we investigated. This comparison allows us to describe the various processes concerning groundwater flow and thermal regimes for the different urban settings. Furthermore, the results facilitate defining goals for specific aquifer regions, including future aquifer use and urbanization, as well as evaluating the thermal use potential for these regions. As one example for a more sustainable thermal use of subsurface water resources, we introduce the thermal management concept of the "relaxation factor", which is a first approach to overcome the present policy of "first come, first served". Remediation measures to regenerate overheated urban aquifers are also introduced. The transferability of the applied methods to other urban areas is discussed. It is shown that an appropriate selection of locations for monitoring hydraulic and thermal boundary conditions make it possible to implement representative interpretations of groundwater flow and thermal regimes as well as to set up high-resolution numerical flow- and heat-transport models. Those models are the basis for the sustainable management of thermal resources.

Subsurface banding poultry litter impacts greenhouse gas emissions

USDA-ARS?s Scientific Manuscript database

The impact subsurface banding poultry litter (PL) has on greenhouse gas emissions is limited. Thus, a study was conducted in established bermudagrass pastures located in Coastal Plain and Piedmont regions to determine the effects subsurface applying PL has on soil flux using two different band spaci...

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

NASA Astrophysics Data System (ADS)

Rose, K.

2016-12-01

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

Direct Laser Ice Penetrator for Exploring Icy Ocean Worlds: Design, Modeling and Test Results of a Proof-of-Concept Prototype

NASA Astrophysics Data System (ADS)

Hogan, B.; Stone, W.; Bramall, N. E.; Siegel, V.; Lelievre, S.; Rothhammer, B.; Richmond, K.; Flesher, C.

2016-12-01

Subsurface exploration of icy ocean worlds requires an efficient method of penetrating ice to significant depths under extreme environment conditions. Searching for extant life dictates descent to a depth which is habitable or where biomarkers can survive and allow detection. It's anticipated that several meters to 10s of meters of shielding is required to prevent cosmic background radiation and other energetic particles from destroying biomarker evidence. We have devised, developed and demonstrated an entirely novel ice penetrating technology utilizing laser light carried by an optical fiber tether and emitted from a probe's optical nose cone and radiated directly into the volume of ice preceding the penetrator. We have termed it a "Direct Laser Penetrator" or DLP. We present design details, modeling, and test data from preliminary proof-of-concept experiments conducted at Stone Aerospace with results exceeding expectations and achieving the fastest reported thermal probe descent rate to date (> 12 m / hr). DLP has critical benefits over conventional "hot point" melt probes, which must generate large temperature gradients to force heat by conduction through the nose cone, and layers of ice and water. Additionally, hot point melt probes tested under vacuum have shown extreme difficulty initiating penetration, as virtually no thermal contact exists between the probe nose and rough ice surface. The ice simply sublimates and any transferred heat is quickly dissipated due to the low power density and extreme cold. DLP requires NO thermal contact between the probe nose and the ice surface since the laser energy is radiated directly into the volume (vs. surface) of ice preceding the penetrator. A proposed key element of the DLP is the fiber optic tether, coupled with a dedicated sensor fiber, enables "optical access" to the subsurface environment by a lander's shared or DLP dedicated on-board instruments (Raman / Fluorescence / fiber / UV / VIS / NIR spectroscopy, etc). These sensors can search for extant life by detecting biomarkers as well as characterizing the radiation / light environment for subsurface habitability. The combination of a laser penetrator w/ integrated fiber coupled instruments could be an important tool for an icy ocean worlds lander. (Supported by NASA funded SAS projects VALKYRIE and SPINDLE)

The effect of soil heterogeneity on ATES performance

NASA Astrophysics Data System (ADS)

Sommer, W.; Rijnaarts, H.; Grotenhuis, T.; van Gaans, P.

2012-04-01

Due to an increasing demand for sustainable energy, application of Aquifer Thermal Energy Storage (ATES) is growing rapidly. Large-scale application of ATES is limited by the space that is available in the subsurface. Especially in urban areas, suboptimal performance is expected due to thermal interference between individual wells of a single system, or interference with other ATES systems or groundwater abstractions. To avoid thermal interference there are guidelines on well spacing. However, these guidelines, and also design calculations, are based on the assumption of a homogeneous subsurface, while studies report a standard deviation in logpermeability of 1 to 2 for unconsolidated aquifers (Gelhar, 1993). Such heterogeneity may create preferential pathways, reducing ATES performance due to increased advective heat loss or interference between ATES wells. The role of hydraulic heterogeneity of the subsurface related to ATES performance has received little attention in literature. Previous research shows that even small amounts of heterogeneity can result in considerable uncertainty in the distribution of thermal energy in the subsurface and an increased radius of influence (Ferguson, 2007). This is supported by subsurface temperature measurements around ATES wells, which suggest heterogeneity gives rise to preferential pathways and short-circuiting between ATES wells (Bridger and Allen, 2010). Using 3-dimensional stochastic heat transport modeling, we quantified the influence of heterogeneity on the performance of a doublet well energy storage system. The following key parameters are varied to study their influence on thermal recovery and thermal balance: 1) regional flow velocity, 2) distance between wells and 3) characteristics of the heterogeneity. Results show that heterogeneity at the scale of a doublet ATES system introduces an uncertainty up to 18% in expected thermal recovery. The uncertainty increases with decreasing distance between ATES wells. The uncertainty in the thermal balance ratio related to heterogeneity is limited (smaller than 3%). If thermal interference should be avoided, wells in heterogeneous aquifers should be placed further apart than in homogeneous aquifers, leading to larger volume claim in the subsurface. By relating the number of ATES systems in an area to their expected performance, these results can be used to optimize regional application of ATES. Bridger, D. W. and D. M. Allen (2010). "Heat transport simulations in a heterogeneous aquifer used for aquifer thermal energy storage (ATES)." Canadian Geotechnical Journal 47(1): 96-115. Ferguson, G. (2007). "Heterogeneity and thermal modeling of ground water." Ground Water 45(4): 485-490. Gelhar, L. W. (1993). Stochastic Subsurface Hydrology, Prentice Hall.

Nutrient loss in leachate and surface runoff from surface-broadcast and subsurface-banded broiler litter

USDA-ARS?s Scientific Manuscript database

Subsurface band application of poultry litter has been shown to reduce the transport of nutrients from fields in surface runoff, compared to the conventional surface broadcast application. Little in situ research has been conducted to determine effects of surface broadcast application and subsurfac...

Crustal control of dissipative ocean tides in Enceladus and other icy moons

NASA Astrophysics Data System (ADS)

Beuthe, Mikael

2016-12-01

Could tidal dissipation within Enceladus' subsurface ocean account for the observed heat flow? Earthlike models of dynamical tides give no definitive answer because they neglect the influence of the crust. I propose here the first model of dissipative tides in a subsurface ocean, by combining the Laplace Tidal Equations with the membrane approach. For the first time, it is possible to compute tidal dissipation rates within the crust, ocean, and mantle in one go. I show that oceanic dissipation is strongly reduced by the crustal constraint, and thus contributes little to Enceladus' present heat budget. Tidal resonances could have played a role in a forming or freezing ocean less than 100 m deep. The model is general: it applies to all icy satellites with a thin crust and a shallow ocean. Scaling rules relate the resonances and dissipation rate of a subsurface ocean to the ones of a surface ocean. If the ocean has low viscosity, the westward obliquity tide does not move the crust. Therefore, crustal dissipation due to dynamical obliquity tides can differ from the static prediction by up to a factor of two.

Analysis of temperature time series to estimate direction and magnitude of water fluxes in near-surface sediments

NASA Astrophysics Data System (ADS)

Munz, Matthias; Oswald, Sascha E.; Schmidt, Christian

2017-04-01

The application of heat as a hydrological tracer has become a standard method for quantifying water fluxes between groundwater and surface water. Typically, time series of temperatures in the surface water and in the sediment are observed and are subsequently evaluated by a vertical 1D representation of heat transport by advection and dispersion. Several analytical solutions as well as their implementation into user-friendly software exist in order to estimate water fluxes from the observed temperatures. The underlying assumption of a stationary, one-dimensional vertical flow field is frequently violated in natural systems. Here subsurface water flow often has a significant horizontal component. We developed a methodology for identifying the geometry of the subsurface flow field based on the variations of diurnal temperature amplitudes with depths. For instance: Purely vertical heat transport is characterized by an exponential decline of temperature amplitudes with increasing depth. Pure horizontal flow would be indicated by a constant, depth independent vertical amplitude profile. The decline of temperature amplitudes with depths could be fitted by polynomials of different order whereby the best fit was defined by the highest Akaike Information Criterion. The stepwise model optimization and selection, evaluating the shape of vertical amplitude ratio profiles was used to determine the predominant subsurface flow field, which could be systematically categorized in purely vertical and horizontal (hyporheic, parafluvial) components. Analytical solutions to estimate water fluxes from the observed temperatures are restricted to specific boundary conditions such as a sinusoidal upper temperature boundary. In contrast numerical solutions offer higher flexibility and can handle temperature data which is characterized by irregular variations such as storm-event induced temperature changes and thus cannot readily be incorporated in analytical solutions. There are several numerical models that simulate heat transport in porous media (e.g. VS2DH, HydroGeoSphere, FEFLOW) but there can be a steep learning curve to the modelling frameworks and may therefore not readily accessible to routinely infer water fluxes between groundwater and surface water. We developed a user-friendly, straightforeward to use software to estimate water FLUXes Based On Temperatures- FLUX-BOT. FLUX-BOT is a numerical code written in MATLAB that calculates time variable vertical water fluxes in saturated sediments based on the inversion of measured temperature time series observed at multiple depths. It applies a cell-centered Crank-Nicolson implicit finite difference scheme to solve the one-dimensional heat advection-conduction equation (FLUX-BOT can be downloaded from the following web site: https://bitbucket.org/flux-bot/flux-bot). We provide applications of FLUX-BOT to generic as well as to measured temperature data to demonstrate its performance. Both, the empirical analysis of temperature amplitudes as well as the numerical inversion of measured temperature time series to estimate the vertical magnitude of water fluxes extent the suite of current heat tracing methods and may provide insight into temperature data from an additional perspective.

Modeling Regolith Temperatures and Volatile Ice Processes (Invited)

NASA Astrophysics Data System (ADS)

Mellon, M. T.

2013-12-01

Surface and subsurface temperatures are an important tool for exploring the distribution and dynamics of volatile ices on and within planetary regoliths. I will review thermal-analysis approaches and recent applications in the studies of volatile ice processes. Numerical models of regolith temperatures allow us to examine the response of ices to periodic and secular changes in heat sources such as insolation. Used in conjunction with spatially and temporally distributed remotely-sensed temperatures, numerical models can: 1) constrain the stability and dynamics of volatile ices; 2) define the partitioning between phases of ice, gas, liquid, and adsorbate; and 3) in some instances be used to probe the distribution of ice hidden from view beneath the surface. The vapor pressure of volatile ices (such as water, carbon dioxide, and methane) depends exponentially on temperature. Small changes in temperature can result in transitions between stable phases. Cyclic temperatures and the propagation of thermal waves into the subsurface can produce a strong hysteresis in the population and partitioning of various phases (such as between ice, vapor, and adsorbate) and result in bulk transport. Condensation of ice will also have a pronounced effect on the thermal properties of otherwise loose particulate regolith. Cementing grains at their contacts through ice deposition will increase the thermal conductivity, and may enhance the stability of additional ice. Likewise sintering of grains within a predominantly icy regolith will increase the thermal conductivity. Subsurface layers that result from ice redistribution can be discriminated by remote sensing when combined with numerical modeling. Applications of these techniques include modeling of seasonal carbon dioxide frosts on Mars, predicting and interpreting the subsurface ice distribution on Mars and in Antarctica, and estimating the current depth of ice-rich permafrost on Mars. Additionally, understanding cold trapping ices in regions of the regolith of airless bodies, such as Mercury and the Moon, are aided by numerical modeling of regolith temperatures. Thermally driven sublimation of volatiles (water ice on Mars and more exotic species on icy moons in the outer solar system) can result in terrain degradation and collapse.

Magnetically-driven oceans on Jovian satellites

NASA Astrophysics Data System (ADS)

Gissinger, C.; Petitdemange, L.

2017-12-01

During the last decade, data from Galileo space missions have added strong support for the existence of subsurface liquid oceans on several moons of Jupiter. For instance, it is now commonly accepted that an electrically conducting fluid beneath the icy crust of Europa's surface may explain the variations of the induced field measured near the satellite. These observations have raised many questions regarding the size and the salinity of such subsurface ocean, or how and why the water remains liquid. In addition, the hydrodynamics of such oceans is mostly unknown. These questions are of primary importance since Europa is often considered as a good candidate for the presence of life beyond the Earth. Here, we present the first numerical modeling of the rapidly-rotating magnetohydrodynamic (MHD) flow generated in Europa's interior: due to Jupiter's rotation with respect to Europa, we show that the Lorentz force induced by the time-varying Jovian magnetic field is able to generate an oceanic flow of a few km/h. Our results are understood in the framework of a simple theoretical model and we obtain a scaling law for the prediction of the mean oceanic velocity and the total heating generated inside the ocean of Europa. Finally, by comparing our simulations to Galileo observations, we make predictions on both the thickness and the electrical conductivity of the ocean of different Jovian's satellites.

The EXTASE thermal probe: Laboratory investigation and modelling of thermal properties

NASA Astrophysics Data System (ADS)

Kaufmann, E.; Knollenberg, J.; Kargl, G.; Koemle, N. I.

2011-10-01

In recent years space missions including landing devices are getting more important. These missions allow in-situ measurements and lead therefore to information on the structure and behavior of extraterrestrial surface and subsurface layers. Sensors used for this kind of missions have to be adapted to the non-terrestrial environment conditions. The better the properties of the single elements of each sensor are known, the more precise are the results from the data evaluation of in-situ measurements. We present the results of thermal conductivity measurements and simulations done for the fiber compound tube used as structural element for the heating segments of the MUPUS-PEN and EXTASE - a spin-off project of Rosetta/MUPUS.

Long-term temperature monitoring at the biological community site on the Nankai accretionary prism off Kii Peninsula

NASA Astrophysics Data System (ADS)

Goto, S.; Hamamoto, H.; Yamano, M.; Kinoshita, M.; Ashi, J.

2008-12-01

Nankai subduction zone off Kii Peninsula is one of the most intensively surveyed areas for studies on the seismogenic zone. Multichannel seismic reflection surveys carried out in this area revealed the existence of splay faults that branched from the subduction zone plate boundary [Park et al., 2002]. Along the splay faults, reversal of reflection polarity was observed, indicating elevated pore fluid pressure along the faults. Cold seepages with biological communities were discovered along a seafloor outcrop of one of the splay faults through submersible observations. Long-term temperature monitoring at a biological community site along the outcrop revealed high heat flow carried by upward fluid flow (>180 mW/m2) [Goto et al., 2003]. Toki et al. [2004] estimated upward fluid flow rates of 40-200 cm/yr from chloride distribution of interstitial water extracted from sediments in and around biological community sites along the outcrop. These observation results suggest upward fluid flow along the splay fault. In order to investigate hydrological nature of the splay fault, we conducted long-term temperature monitoring again in the same cold seepage site where Goto et al. [2003] carried out long-term temperature monitoring. In this presentation, we present results of the temperature monitoring and estimate heat flow carried by upward fluid flow from the temperature records. In this long-term temperature monitoring, we used stand-alone heat flow meter (SAHF), a probe-type sediment temperature recorder. Two SAHFs (SAHF-3 and SAHF-4) were used in this study. SAHF-4 was inserted into a bacterial mat, within several meters of which the previous long-term temperature monitoring was conducted. SAHF-3 was penetrated into ordinary sediment near the bacterial mat. The sub-bottom temperature records were obtained for 8 months. The subsurface temperatures oscillated reflecting bottom- water temperature variation (BTV). For sub-bottom temperatures measured with SAHF-3 (outside of the bacterial mat), we found that the effects of the BTV propagated into sediment by conduction only. By correcting the effect of the BTV, conductive heat flow estimated is higher than 100 mW/m2. Sub-bottom temperatures measured within bacterial mat (SAHF-4) except for the topmost sensor could be explained by a conduction model. The heat flow estimated based on the conduction model is similar to that measured with SAHF-3. The temperature of the topmost sensor is slightly higher than that expected from the conduction model. To explain the high temperature, upward fluid flow at a rate of 10-7 m/s order is needed. Heat flow carried by the upward fluid flow is higher than that estimated by Goto et al. [2003]. Heat flow value expected from the distribution of heat flow around this area is 70-80 mW/m2. The high heat flow values inside and outside the bacterial mat estimated in the present and previous studies may reflect upward fluid flow along the splay fault.

Entropy Production in Convective Hydrothermal Systems

NASA Astrophysics Data System (ADS)

Boersing, Nele; Wellmann, Florian; Niederau, Jan

2016-04-01

Exploring hydrothermal reservoirs requires reliable estimates of subsurface temperatures to delineate favorable locations of boreholes. It is therefore of fundamental and practical importance to understand the thermodynamic behavior of the system in order to predict its performance with numerical studies. To this end, the thermodynamic measure of entropy production is considered as a useful abstraction tool to characterize the convective state of a system since it accounts for dissipative heat processes and gives insight into the system's average behavior in a statistical sense. Solving the underlying conservation principles of a convective hydrothermal system is sensitive to initial conditions and boundary conditions which in turn are prone to uncertain knowledge in subsurface parameters. There exist multiple numerical solutions to the mathematical description of a convective system and the prediction becomes even more challenging as the vigor of convection increases. Thus, the variety of possible modes contained in such highly non-linear problems needs to be quantified. A synthetic study is carried out to simulate fluid flow and heat transfer in a finite porous layer heated from below. Various two-dimensional models are created such that their corresponding Rayleigh numbers lie in a range from the sub-critical linear to the supercritical non-linear regime, that is purely conductive to convection-dominated systems. Entropy production is found to describe the transient evolution of convective processes fairly well and can be used to identify thermodynamic equilibrium. Additionally, varying the aspect ratio for each Rayleigh number shows that the variety of realized convection modes increases with both larger aspect ratio and higher Rayleigh number. This phenomenon is also reflected by an enlarged spread of entropy production for the realized modes. Consequently, the Rayleigh number can be correlated to the magnitude of entropy production. In cases of moderate Rayleigh number and moderate aspect ratio, entropy production even enables to predict a preferred convection mode for a model with homogeneous parameter distribution. As a general rule, the thermodynamic measure of entropy production can be used to analyze uncertainties accompanied by modelling convective hydrothermal systems. Without considering any probability distributions of input data, this synthetic study shows that a higher entropy production implies a lower ability to uniquely predict the convection pattern. This in turn means that the uncertainty in estimating subsurface temperatures is higher.

Evaluation of several methods of applying sewage effluent to forested soils in the winter.

Treesearch

Alfred Ray Harris

1978-01-01

Surface application methods result in heat loss, deep soil frost, and surface ice accumulations; subsurface methods decrease heat loss and produce shallower frost. Distribution of effluent within the frozen soil is a function of surface application methods, piping due to macropores and biopores, and water movement due to temperature gradients. Nitrate is not...

Shallow Groundwater Temperatures and the Urban Heat Island Effect: the First U.K City-wide Geothermal Map to Support Development of Ground Source Heating Systems Strategy

NASA Astrophysics Data System (ADS)

Patton, Ashley M.; Farr, Gareth J.; Boon, David P.; James, David R.; Williams, Bernard; Newell, Andrew J.

2015-04-01

The first UK city-wide heat map is described based on measurements of groundwater from a shallow superficial aquifer in the coastal city of Cardiff, Wales, UK. The UK Government has a target of reducing greenhouse gas emissions by 80% by 2050 (Climate Change Act 2008) and low carbon technologies are key to achieving this. To support the use of ground source heating we characterised the shallow heat potential of an urban aquifer to produce a baseline dataset which is intended to be used as a tool to inform developers and to underpin planning and regulation. We exploited an existing network of 168 groundwater monitoring boreholes across the city, recording the water temperature in each borehole at 1m depth intervals up to a depth of 20m. We recorded groundwater temperatures during the coldest part of 2014, and repeat profiling of the boreholes in different seasons has added a fourth dimension to our results and allowed us to characterise the maximum depth of seasonal temperature fluctuation. The temperature profiles were used to create a 3D model of heat potential within the aquifer using GOCAD® and the average borehole temperatures were contoured using Surfer® 10 to generate a 2D thermal resource map to support future assessment of urban Ground Source Heat Pumps prospectively. The average groundwater temperature in Cardiff was found to be above the average for England and Wales (11.3°C) with 90% of boreholes in excess of this figure by up to 4°C. The subsurface temperature profiles were also found to be higher than forecast by the predicted geothermal gradient for the area. Potential sources for heat include: conduction from buildings, basements and sub-surface infrastructure; insulation effects of the urban area and of the geology, and convection from leaking sewers. Other factors include recharge inhibition by drains, localised confinement and rock-water interaction in specific geology. It is likely to be a combination of multiple factors which we are hoping to make the focus of future study. The next stage of this work will be to develop conceptual models of the thermal groundwater regime, and monitoring under abstraction conditions to confirm the sustainability of groundwater temperatures as a long-term thermal resource. We have also instrumented a non-infiltration Sustainable Urban Drainage System (SuDS) scheme, where we will characterise the effect upon the thermal groundwater resource as localised infiltration is reduced.

Radiometric Measurements of the Thermal Conductivity of Complex Planetary-like Materials

NASA Astrophysics Data System (ADS)

Piqueux, S.; Christensen, P. R.

2012-12-01

Planetary surface temperatures and thermal inertias are controlled by the physical and compositional characteristics of the surface layer material, which result from current and past geological activity. For this reason, temperature measurements are often acquired because they provide fundamental constraints on the geological history and habitability. Examples of regolith properties affecting surface temperatures and inertias are: grain sizes and mixture ratios, solid composition in the case of ices, presence of cement between grains, regolith porosity, grain roughness, material layering etc.. Other important factors include volatile phase changes, and endogenic or exogenic heat sources (i.e. geothermal heat flow, impact-related heat, biological activity etc.). In the case of Mars, the multitude of instruments observing the surface temperature at different spatial and temporal resolutions (i.e. IRTM, Thermoskan, TES, MiniTES, THEMIS, MCS, REMS, etc.) in conjunction with other instruments allows us to probe and characterize the thermal properties of the surface layer with an unprecedented resolution. While the derivation of thermal inertia values from temperature measurements is routinely performed by well-established planetary regolith numerical models, constraining the physical properties of the surface layer from thermal inertia values requires the additional step of laboratory measurements. The density and specific heat are usually constant and sufficiently well known for common geological materials, but the bulk thermal conductivity is highly variable as a function of the physical characteristics of the regolith. Most laboratory designs do not allow an investigation of the thermal conductivity of complex regolith configurations similar to those observed on planetary surfaces (i.e. cemented material, large grains, layered material, and temperature effects) because the samples are too small and need to be soft to insert heating or measuring devices. For this reason, we have built a new type of apparatus to measure the thermal conductivity of sample significantly larger than previous apparatus under planetary conditions of atmosphere and gas composition. Samples' edges are cooled down from room to LN2 temperature and the surface material temperature is recorded by an infrared camera without inserting thermocouples or heat sources. Sample surface cooling trends are fit with finite element models of heat transfer to retrieve the material thermal conductivity. Preliminary results confirm independent numerical modeling results predicting the thermal conductivity of complex materials: the thermal inertia of particulate material under Mars conditions is temperature-dependent, small amounts of cements significantly increase the bulk conductivity and inertia of particulate material, and one-grain-thick armors similar to those observed by the Mars Exploration Rovers behave like a thin highly conductive layer that does not significantly influence apparent thermal inertias. These results are used to further our interpretation of Martian temperature observations. For example local amounts of subsurface water ice or the fraction of cementing phase in the global Martian duricrust can be constrained; the search for subtle changes in near-surface heat flow can be performed more accurately, and surface thermal inertias under various atmospheric conditions of pressure and gas composition can be predicted.

A coupled subsurface-boundary layer model of water on Mars

NASA Astrophysics Data System (ADS)

Zent, A. P.; Haberle, R. M.; Houben, H. C.; Jakosky, B. M.

1993-02-01

A 1D numerical model of the exchange of H2O between the atmosphere and subsurface of Mars through the PBL is employed to explore the mechanisms of H2O exchange and to elucidate the role played by the regolith in the local H2O budget. The atmospheric model includes effects of Coriolis, pressure gradient, and frictional forces for momentum: radiation, sensible heat flux, and advection for heat. It is suggested that in most cases, the flux through the Martian surface reverses twice in the course of each sol. The effects of surface albedo, thermal inertia, solar declination, atmospheric optical depth, and regolith pore structure are explored. It is proposed that higher thermal inertia forces more H2O into the atmosphere because the regolith is warmer at depth.

Holocene evolution of the North Atlantic subsurface transport

NASA Astrophysics Data System (ADS)

Repschläger, Janne; Garbe-Schönberg, Dieter; Weinelt, Mara; Schneider, Ralph

2017-04-01

Previous studies suggested that short-term freshening events in the subpolar gyre can be counterbalanced by advection of saline waters from the subtropical gyre and thus stabilize the Atlantic Meridional Overturning Circulation (AMOC). However, little is known about the inter-gyre transport pathways. Here, we infer changes in surface and subsurface transport between the subtropical and polar North Atlantic during the last 11 000 years, by combining new temperature and salinity reconstructions obtained from combined δ18O and Mg / Ca measurements on surface and subsurface dwelling foraminifera with published foraminiferal abundance data from the subtropical North Atlantic, and with salinity and temperature data from the tropical and subpolar North Atlantic. This compilation implies an overall stable subtropical warm surface water transport since 10 ka BP. In contrast, subsurface warm water transport started at about 8 ka but still with subsurface heat storage in the subtropical gyre. The full strength of intergyre exchange was probably reached only after the onset of northward transport of warm saline subsurface waters at about 7 ka BP, associated with the onset of the modern AMOC mode. A critical evaluation of different potential forcing mechanisms leads to the assumption that freshwater supply from the Laurentide Ice Sheet was the main control on subtropical to subpolar ocean transport at surface and subsurface levels.

Combined use of heat and saline tracer to estimate aquifer properties in a forced gradient test

NASA Astrophysics Data System (ADS)

Colombani, N.; Giambastiani, B. M. S.; Mastrocicco, M.

2015-06-01

Usually electrolytic tracers are employed for subsurface characterization, but the interpretation of tracer test data collected by low cost techniques, such as electrical conductivity logging, can be biased by cation exchange reactions. To characterize the aquifer transport properties a saline and heat forced gradient test was employed. The field site, located near Ferrara (Northern Italy), is a well characterized site, which covers an area of 200 m2 and is equipped with a grid of 13 monitoring wells. A two-well (injection and pumping) system was employed to perform the forced gradient test and a straddle packer was installed in the injection well to avoid in-well artificial mixing. The contemporary continuous monitor of hydraulic head, electrical conductivity and temperature within the wells permitted to obtain a robust dataset, which was then used to accurately simulate injection conditions, to calibrate a 3D transient flow and transport model and to obtain aquifer properties at small scale. The transient groundwater flow and solute-heat transport model was built using SEAWAT. The result significance was further investigated by comparing the results with already published column experiments and a natural gradient tracer test performed in the same field. The test procedure shown here can provide a fast and low cost technique to characterize coarse grain aquifer properties, although some limitations can be highlighted, such as the small value of the dispersion coefficient compared to values obtained by natural gradient tracer test, or the fast depletion of heat signal due to high thermal diffusivity.

Impact disruption and recovery of the deep subsurface biosphere

USGS Publications Warehouse

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

2012-01-01

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

Impact disruption and recovery of the deep subsurface biosphere.

PubMed

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

2012-03-01

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

Vadose zone dynamics governing snowmelt infiltration and groundwater recharge in a seasonally frozen, semi-arid landscape

NASA Astrophysics Data System (ADS)

Mohammed, A.; LeBlanc, F.; Cey, E. E.; Hayashi, M.

2016-12-01

Snowmelt infiltration and vadose zone fluxes in seasonally frozen soils are strongly affected by meteorological and soil moisture dynamics occurring during the preceding fall and winter, and complex processes controlling soil hydraulic and thermal regimes. In order to predict their effects on hydrologic processes such as run-off generation, groundwater recharge and plant-water availability in cold regions, an improved understanding of the mechanisms governing coupled water and heat fluxes in the unsaturated zone is needed. Field and laboratory studies were conducted to investigate snowmelt infiltration and groundwater recharge through partially frozen ground over a range of climate and soil conditions in the Canadian Prairies. Meteorological and subsurface field measurements at three sites were combined with laboratory infiltration experiments on frozen undisturbed soil-columns to provide insights into the hydraulic and thermal processes governing water movement. Analysis reveals that antecedent moisture content and thermal profiles both strongly affect subsurface dynamics during infiltration of snowmelt. Preferential flow is also a critical parameter, as both thermal and hydraulic responses were observed at depth prior to complete ground thaw in the field; as well as drainage outflow from the frozen soil column experiments under certain conditions. Results indicate that both diffuse (matrix) and preferential (macropore) flow play significant roles in the infiltration and redistribution of snowmelt water under frozen soil conditions, and shallow groundwater recharge. This study highlights the critical subsurface factors and processes that control infiltration and groundwater recharge in these seasonally frozen landscapes.

Application of a 3D Model to Assess the Thermo-Hydrological Effects of Climate Warming in a Discontinuous Permafrost Zone, Umiujaq, Northern Quebec, Canada

NASA Astrophysics Data System (ADS)

Parhizkar, M.; Therrien, R.; Molson, J. W. H.; Lemieux, J. M.; Fortier, R.; Talbot Poulin, M. C.; Therrien, P.; Ouellet, M.

2016-12-01

The rate of permafrost degradation in northern Quebec, Canada, has increased over the last two decades due to climate warming, which is expected to significantly modify the hydrogeologic and thermal regimes. Groundwater accessibility is also expected to increase and could become a significant source of drinking water for northern communities. In this project, an integrated surface water / groundwater flow model, HydroGeoSphere, is being applied to a 2 km2catchment in northern Quebec to assess the effect of future climate change on thermo-hydrological conditions as well as on changes in groundwater availability for northern communities. The catchment is located in a discontinuous but widespread permafrost zone near Umiujaq (northern Quebec, Canada) where the subsurface consists of a 10-30 m-thick coarse-grained glaciofluvial layer forming a good aquifer beneath a permafrost-rich silty marine unit. A conceptual thermo-hydrological model of the catchment has been built from field data collected over 5 years, including hydraulic heads, stream flow rates, subsurface geology, as well as ground temperatures and thermal fluxes around two 10-20 m-thick permafrost mounds. The integrated 3D numerical model includes variably-saturated groundwater flow with transient recharge, as well as advective-conductive heat transport driven by transient air temperatures (varying from about -40 to +30 ºC) and a geothermal heat flux of 60 mW/m2. The model is calibrated to observed heads and temperatures by coupling PEST with HydroGeoSphere, allowing changes in hydraulic and thermal conductivities. Preliminary results are consistent with the available observed data, however non-uniqueness remains an important issue. The simulations are providing useful predictions of the permafrost thaw rate and associated changes to the hydrogeological flow system, including increased aquifer recharge following permafrost thaw.

Parallel heater system for subsurface formations

DOEpatents

Harris, Christopher Kelvin [Houston, TX; Karanikas, John Michael [Houston, TX; Nguyen, Scott Vinh [Houston, TX

2011-10-25

A heating system for a subsurface formation is disclosed. The system includes a plurality of substantially horizontally oriented or inclined heater sections located in a hydrocarbon containing layer in the formation. At least a portion of two of the heater sections are substantially parallel to each other. The ends of at least two of the heater sections in the layer are electrically coupled to a substantially horizontal, or inclined, electrical conductor oriented substantially perpendicular to the ends of the at least two heater sections.

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

Treesearch

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

2010-01-01

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

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

PubMed Central

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

2017-01-01

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

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

PubMed

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

2017-07-31

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

Subsurface heaters with low sulfidation rates

DOEpatents

John, Randy Carl; Vinegar, Harold J

2013-12-10

A system for heating a hydrocarbon containing formation includes a heater having an elongated ferromagnetic metal heater section. The heater is located in an opening in a formation. The heater section is configured to heat the hydrocarbon containing formation. The exposed ferromagnetic metal has a sulfidation rate that goes down with increasing temperature of the heater, when the heater is in a selected temperature range.

Thermal wave interference with high-power VCSEL arrays for locating vertically oriented subsurface defects

NASA Astrophysics Data System (ADS)

Thiel, Erik; Kreutzbruck, Marc; Studemund, Taarna; Ziegler, Mathias

2018-04-01

Among the photothermal methods, full-field thermal imaging is used to characterize materials, to determine thicknesses of layers, or to find inhomogeneities such as voids or cracks. The use of classical light sources such as flash lamps (impulse heating) or halogen lamps (modulated heating) led to a variety of nondestructive testing methods, in particular, lock-in and flash-thermography. In vertical-cavity surface-emitting lasers (VCSELs), laser light is emitted perpendicularly to the surface with a symmetrical beam profile. Due to the vertical structure, they can be arranged in large arrays of many thousands of individual lasers, which allows power scaling into the kilowatt range. Recently, a high-power yet very compact version of such a VCSEL-array became available that offers both the fast timing behavior of a laser as well as the large illumination area of a lamp. Moreover, it allows a spatial and temporal control of the heating because individual parts of the array can be controlled arbitrarily in frequency, amplitude, and phase. In conjunction with a fast infrared camera, such structured heating opens up a field of novel thermal imaging and testing methods. As a first demonstration of this approach, we chose a testing problem very challenging to conventional thermal infrared testing: The detection of very thin subsurface defects perpendicularly oriented to the surface of metallic samples. First, we generate destructively interfering thermal wave fields, which are then affected by the presence of defects within their reach. It turned out that this technique allows highly sensitive detection of subsurface defects down to depths in excess of the usual thermographic rule of thumb, with no need for a reference or surface preparation.

BASIMO - Borehole Heat Exchanger Array Simulation and Optimization Tool

NASA Astrophysics Data System (ADS)

Schulte, Daniel O.; Bastian, Welsch; Wolfram, Rühaak; Kristian, Bär; Ingo, Sass

2017-04-01

Arrays of borehole heat exchangers are an increasingly popular source for renewable energy. Furthermore, they can serve as borehole thermal energy storage (BTES) systems for seasonally fluctuating heat sources like solar thermal energy or district heating grids. The high temperature level of these heat sources prohibits the use of the shallow subsurface for environmental reasons. Therefore, deeper reservoirs have to be accessed instead. The increased depth of the systems results in high investment costs and has hindered the implementation of this technology until now. Therefore, research of medium deep BTES systems relies on numerical simulation models. Current simulation tools cannot - or only to some extent - describe key features like partly insulated boreholes unless they run fully discretized models of the borehole heat exchangers. However, fully discretized models often come at a high computational cost, especially for large arrays of borehole heat exchangers. We give an update on the development of BASIMO: a tool, which uses one dimensional thermal resistance and capacity models for the borehole heat exchangers coupled with a numerical finite element model for the subsurface heat transport in a dual-continuum approach. An unstructured tetrahedral mesh bypasses the limitations of structured grids for borehole path geometries, while the thermal resistance and capacity model is improved to account for borehole heat exchanger properties changing with depth. Thereby, partly insulated boreholes can be considered in the model. Furthermore, BASIMO can be used to improve the design of BTES systems: the tool allows for automated parameter variations and is readily coupled to other code like mathematical optimization algorithms. Optimization can be used to determine the required minimum system size or to increase the system performance.

Mechanisms influencing seasonal to inter-annual prediction skill of sea ice extent in the Arctic Ocean in MIROC

NASA Astrophysics Data System (ADS)

Ono, Jun; Tatebe, Hiroaki; Komuro, Yoshiki; Nodzu, Masato I.; Ishii, Masayoshi

2018-02-01

To assess the skill of seasonal to inter-annual predictions of the detrended sea ice extent in the Arctic Ocean (SIEAO) and to clarify the underlying physical processes, we conducted ensemble hindcasts, started on 1 January, 1 April, 1 July and 1 October for each year from 1980 to 2011, for lead times up to three years, using the Model for Interdisciplinary Research on Climate (MIROC) version 5 initialised with the observed atmosphere and ocean anomalies and sea ice concentration. Significant skill is found for the winter months: the December SIEAO can be predicted up to 11 months ahead (anomaly correlation coefficient is 0.42). This skill might be attributed to the subsurface ocean heat content originating in the North Atlantic. A plausible mechanism is as follows: the subsurface water flows into the Barents Sea from spring to fall and emerges at the surface in winter by vertical mixing, and eventually affects the sea ice variability there. Meanwhile, the September SIEAO predictions are skillful for lead times of up to two months, due to the persistence of sea ice in the Beaufort, Chukchi, and East Siberian seas initialised in July, as suggested by previous studies.

Vibrational Action Spectroscopy of Solids: New Surface-Sensitive Technique

NASA Astrophysics Data System (ADS)

Wu, Zongfang; Płucienik, Agata; Feiten, Felix E.; Naschitzki, Matthias; Wachsmann, Walter; Gewinner, Sandy; Schöllkopf, Wieland; Staemmler, Volker; Kuhlenbeck, Helmut; Freund, Hans-Joachim

2017-09-01

Vibrational action spectroscopy employing infrared radiation from a free-electron laser has been successfully used for many years to study the vibrational and structural properties of gas phase aggregates. Despite the high sensitivity of this method no relevant studies have yet been conducted for solid sample surfaces. We have set up an experiment for the application of this method to such targets, using infrared light from the free-electron laser of the Fritz Haber Institute. In this Letter, we present first results of this technique with adsorbed argon and neon atoms as messengers. We were able to detect surface-located vibrations of a thin V2O3(0 0 0 1 ) film on Au(111) as well as adsorbate vibrations, demonstrating that this method is highly surface sensitive. We consider that the dominant channel for desorption of the messenger atoms is direct inharmonic vibrational coupling, which is essentially insensitive to subsurface or bulk vibrations. Another channel is thermal desorption due to sample heating by absorption of infrared light. The high surface sensitivity of the nonthermal channel and its insensitivity to subsurface modes makes this technique an ideal tool for the study of surface-located vibrations.

Vibrational Action Spectroscopy of Solids: New Surface-Sensitive Technique.

PubMed

Wu, Zongfang; Płucienik, Agata; Feiten, Felix E; Naschitzki, Matthias; Wachsmann, Walter; Gewinner, Sandy; Schöllkopf, Wieland; Staemmler, Volker; Kuhlenbeck, Helmut; Freund, Hans-Joachim

2017-09-29

Vibrational action spectroscopy employing infrared radiation from a free-electron laser has been successfully used for many years to study the vibrational and structural properties of gas phase aggregates. Despite the high sensitivity of this method no relevant studies have yet been conducted for solid sample surfaces. We have set up an experiment for the application of this method to such targets, using infrared light from the free-electron laser of the Fritz Haber Institute. In this Letter, we present first results of this technique with adsorbed argon and neon atoms as messengers. We were able to detect surface-located vibrations of a thin V_{2}O_{3}(0001) film on Au(111) as well as adsorbate vibrations, demonstrating that this method is highly surface sensitive. We consider that the dominant channel for desorption of the messenger atoms is direct inharmonic vibrational coupling, which is essentially insensitive to subsurface or bulk vibrations. Another channel is thermal desorption due to sample heating by absorption of infrared light. The high surface sensitivity of the nonthermal channel and its insensitivity to subsurface modes makes this technique an ideal tool for the study of surface-located vibrations.

A drilling tool design and in situ identification of planetary regolith mechanical parameters

NASA Astrophysics Data System (ADS)

Zhang, Weiwei; Jiang, Shengyuan; Ji, Jie; Tang, Dewei

2018-05-01

The physical and mechanical properties as well as the heat flux of regolith are critical evidence in the study of planetary origin and evolution. Moreover, the mechanical properties of planetary regolith have great value for guiding future human planetary activities. For planetary subsurface exploration, an inchworm boring robot (IBR) has been proposed to penetrate the regolith, and the mechanical properties of the regolith are expected to be simultaneously investigated during the penetration process using the drilling tool on the IBR. This paper provides a preliminary study of an in situ method for measuring planetary regolith mechanical parameters using a drilling tool on a test bed. A conical-screw drilling tool was designed, and its drilling load characteristics were experimentally analyzed. Based on the drilling tool-regolith interaction model, two identification methods for determining the planetary regolith bearing and shearing parameters are proposed. The bearing and shearing parameters of lunar regolith simulant were successfully determined according to the pressure-sinkage tests and shear tests conducted on the test bed. The effects of the operating parameters on the identification results were also analyzed. The results indicate a feasible scheme for future planetary subsurface exploration.

Subsurface thermal coagulation of tissues using near infrared lasers

NASA Astrophysics Data System (ADS)

Chang, Chun-Hung Jack

Noninvasive laser therapy is currently limited primarily to cosmetic dermatological applications such as skin resurfacing, hair removal, tattoo removal and treatment of vascular birthmarks. In order to expand applications of noninvasive laser therapy, deeper optical penetration of laser radiation in tissue as well as more aggressive cooling of the tissue surface is necessary. The near-infrared laser wavelength of 1075 nm was found to be the optimal laser wavelength for creation of deep subsurface thermal lesions in liver tissue, ex vivo, with contact cooling, preserving a surface tissue layer of 2 mm. Monte Carlo light transport, heat transfer, and Arrhenius integral thermal damage simulations were conducted at this wavelength, showing good agreement between experiment and simulations. Building on the initial results, our goal is to develop new noninvasive laser therapies for application in urology, specifically for treatment of female stress urinary incontinence (SUI). Various laser balloon probes including side-firing and diffusing fibers were designed and tested for both transvaginal and transurethral approaches to treatment. The transvaginal approach showed the highest feasibility. To further increase optical penetration depth, various types and concentrations of optical clearing agents were also explored. Three cadavers studies were performed to investigate and demonstrate the feasibility of laser treatment for SUI.

Tidal dissipation in the subsurface ocean of Enceladus

NASA Astrophysics Data System (ADS)

Matsuyama, I.; Hay, H.; Nimmo, F.; Kamata, S.

2017-12-01

Icy satellites of the outer solar system have emerged as potential habitable worlds due to the presence of subsurface oceans. As a long-term energy source, tidal heating in these oceans can influence the survivability of subsurface oceans, and the thermal, rotational, and orbital evolution of these satellites. Additionally, the spatial and temporal variation of tidal heating has implications for the interior structure and spacecraft observations. Previous models for dissipation in thin oceans are not generally applicable to icy satellites because either they ignore the presence of an overlying solid shell or use a thin shell membrane approximation. We present a new theoretical treatment for tidal dissipation in thin oceans with overlying shells of arbitrary thickness and apply it to Enceladus. The shell's resistance to ocean tides increases with shell thickness, reducing tidal dissipation as expected. Both the magnitude of energy dissipation and the resonant ocean thicknesses decrease as the overlying shell thickness increases, as previously shown using a membrane approximation. In contrast to previous work based on the traditional definition of the tidal quality factor, Q, our new definition is consistent with higher energy dissipation for smaller Q, and introduces a lower limit on Q. The dissipated power and tides are not in phase with the forcing tidal potential due to the delayed ocean response. The phase lag depends on the Rayleigh friction coefficient and ocean and shell thicknesses, which implies that phase lag observations can be used to constrain these parameters. Eccentricity heating produces higher dissipation near the poles, while obliquity heating produces higher dissipation near the equator, in contrast to the dissipation patterns in the shell. The time-averaged surface distribution of tidal heating can generate lateral shell thickness variations, providing an additional constraint on the Rayleigh friction coefficient. Explaining the endogenic power radiated from the south polar terrain requires shell thicknesses smaller than about 1 km, a value that is not consistent with recent libration, gravity and topography constraints.

Critical Evaluation of State-of-the-Art In Situ Thermal Treatment Technologies for DNAPL Source Zone Treatment. State-of-the-Practice Overview

DTIC Science & Technology

2009-05-01

recovery in their design. Electrodes have been constructed from steel pipe , copper plate for heating distinct zones, and sheet pile. Sheet pile...energy transfer/ heating in the subsurface) The components required to implement ERH include: • Electrodes (steel pipe , copper plate, well points...including piping , blower, and condenser • A vapor treatment system Electrical Resistance Heating (Smith) A-3 • An ERH power control unit to

Subsurface conditions in hydrothermal vents inferred from diffuse flow composition, and models of reaction and transport

NASA Astrophysics Data System (ADS)

Larson, B. I.; Houghton, J. L.; Lowell, R. P.; Farough, A.; Meile, C. D.

2015-08-01

Chemical gradients in the subsurface of mid-ocean ridge hydrothermal systems create an environment where minerals precipitate and dissolve and where chemosynthetic organisms thrive. However, owing to the lack of easy access to the subsurface, robust knowledge of the nature and extent of chemical transformations remains elusive. Here, we combine measurements of vent fluid chemistry with geochemical and transport modeling to give new insights into the under-sampled subsurface. Temperature-composition relationships from a geochemical mixing model are superimposed on the subsurface temperature distribution determined using a heat flow model to estimate the spatial distribution of fluid composition. We then estimate the distribution of Gibb's free energies of reaction beneath mid oceanic ridges and by combining flow simulations with speciation calculations estimate anhydrite deposition rates. Applied to vent endmembers observed at the fast spreading ridge at the East Pacific Rise, our results suggest that sealing times due to anhydrite formation are longer than the typical time between tectonic and magmatic events. The chemical composition of the neighboring low temperature flow indicates relatively uniform energetically favorable conditions for commonly inferred microbial processes such as methanogenesis, sulfate reduction and numerous oxidation reactions, suggesting that factors other than energy availability may control subsurface microbial biomass distribution. Thus, these model simulations complement fluid-sample datasets from surface venting and help infer the chemical distribution and transformations in subsurface flow.

Varying properties along lengths of temperature limited heaters

DOEpatents

Vinegar, Harold J [Bellaire, TX; Xie, Xueying [Houston, TX; Miller, David Scott [Katy, TX; Ginestra, Jean Charles [Richmond, TX

2011-07-26

A system for heating a subsurface formation is described. The system includes an elongated heater in an opening in the formation. The elongated heater includes two or more portions along the length of the heater that have different power outputs. At least one portion of the elongated heater includes at least one temperature limited portion with at least one selected temperature at which the portion provides a reduced heat output. The heater is configured to provide heat to the formation with the different power outputs. The heater is configured so that the heater heats one or more portions of the formation at one or more selected heating rates.

Changes in physical-thermal properties of soil related to very shallow geothermal systems in urban areas

NASA Astrophysics Data System (ADS)

Di Sipio, Eloisa; Psyk, Mario; Popp, Thomas; Bertermann, David

2016-04-01

In the near future the population living in urban areas is expected to increase. This worldwide trend will lead to a high concentrations of infrastructures in confined areas, whose impact on land use and shallow subsurface must be well evaluated. Since shallow geothermal energy resource is becoming increasingly important as renewable energy resource, due to its huge potential in providing thermal energy for residential and tertiary buildings and in contributing to reduce greenhouse gas emission, the number of installed geothermal systems is expected to continue to rise in the near future. However, a leading question concerns the short and long-term effect of an intensive thermal use of the shallow subsurface for heat generation, cooling and thermal energy storage. From an environmental and technical point of view, changes on ground temperatures can influence the physical-thermal properties of soil and groundwater as well as their chemical and biological features. In this study the preliminary results of ITER Project are presented. This project, funded by European Union, focuses on improving heat transfer efficiency of very shallow geothermal systems, as horizontal collector systems or special forms (i.e. helix system), interesting the first 2 m of depth from ground level. Given the heterogeneity of sedimentary deposits in alluvial plain and the uncertainties related to the estimation of thermal parameters for unconsolidated material affected by thermal use, physical-thermal parameters (i.e. moisture content, bulk density, thermal conductivity...) where determined in laboratory for sand, clay and loamy sand samples. In addition, preliminary results from a field test site located within an urban area will be also shown. The main aim is to improve our knowledge of heat transfer process in the soil body in order (i) to create a reference database to compare subsequently the impact of temperature variations on the same properties and (ii) to provide reliable data for model parameterization.

BRNBOX v.1.0

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

Aldridge, David F.

Program BRNBOX conducts a systematic search through a pre-defined 3D volume of candidate sub-surface Born scattering points in order to identify the particular point that minimizes the misfit between predicted (i.e., calculated) and observed electromagnetic (EM) data. This global minimum misfit point is interpreted as the location where electrically conductive proppant is injected into a sub-surface petroleum reservoir in a hydraulic fracturing experiment.

Volcanic geothermal system in the Main Ethiopian Rift: insights from 3D MT finite-element inversion and other exploration methods

NASA Astrophysics Data System (ADS)

Samrock, F.; Grayver, A.; Eysteinsson, H.; Saar, M. O.

2017-12-01

In search for geothermal resources, especially in exploration for high-enthalpy systems found in regions with active volcanism, the magnetotelluric (MT) method has proven to be an efficient tool. Electrical conductivity of the subsurface, imaged by MT, is used for detecting layers of electrically highly conductive clays which form around the surrounding strata of hot circulating fluids and for delineating magmatic heat sources such as zones with partial melting. We present a case study using a novel 3-D inverse solver, based on adaptive local mesh refinement techniques, applied to decoupled forward and inverse mesh parameterizations. The flexible meshing allows accurate representation of surface topography, while keeping computational costs at a reasonable level. The MT data set we analyze was measured at 112 sites, covering an area of 18 by 11 km at a geothermal prospect in the Main Ethiopian Rift. For inverse modelling, we tested a series of different settings to ensure that the recovered structures are supported by the data. Specifically, we tested different starting models, regularization functionals, sets of transfer functions, with and without inclusion of topography. Several robust subsurface structures were revealed. These are prominent features of a high-enthalpy geothermal system: A highly conductive shallow clay cap occurs in an area with high fumarolic activity, and is underlain by a more resistive zone, which is commonly interpreted as a propylitic reservoir and is the main geothermal target for drilling. An interesting discovery is the existence of a channel-like conductor connecting the geothermal field at the surface with an off-rift conductive zone, whose existence was proposed earlier as being related to an off-rift volcanic belt along the western shoulder of the Main Ethiopian Rift. The electrical conductivity model is interpreted together with results from other geoscientific studies and outcomes from satellite remote sensing techniques.

Distinctive ocean interior changes during the recent warming slowdown

PubMed Central

Cheng, Lijing; Zheng, Fei; Zhu, Jiang

2015-01-01

The earth system experiences continuous heat input, but a “climate hiatus” of upper ocean waters has been observed in this century. This leads to a question: where is the extra heat going? Using four in situ observation datasets, we explore the ocean subsurface temperature changes from 2004 to 2013. The observations all show that the ocean has continued to gain heat in this century, which is indicative of anthropogenic global warming. However, a distinctive pattern of change in the interior ocean is observed. The sea surface (1–100 m) temperature has decreased in this century, accompanied by warming in the 101–300 m layer. This pattern is due to the changes in the frequency of El Niño and La Niña events (ENSO characteristics), according to both observations and CMIP5 model simulations. In addition, we show for the first time that the ocean subsurface within 301–700 m experienced a net cooling, indicative of another instance of variability in the natural ocean. Furthermore, the ocean layer of 701–1500 m has experienced significant warming. PMID:26394551

Distinctive ocean interior changes during the recent warming slowdown.

PubMed

Cheng, Lijing; Zheng, Fei; Zhu, Jiang

2015-09-23

The earth system experiences continuous heat input, but a "climate hiatus" of upper ocean waters has been observed in this century. This leads to a question: where is the extra heat going? Using four in situ observation datasets, we explore the ocean subsurface temperature changes from 2004 to 2013. The observations all show that the ocean has continued to gain heat in this century, which is indicative of anthropogenic global warming. However, a distinctive pattern of change in the interior ocean is observed. The sea surface (1-100 m) temperature has decreased in this century, accompanied by warming in the 101-300 m layer. This pattern is due to the changes in the frequency of El Niño and La Niña events (ENSO characteristics), according to both observations and CMIP5 model simulations. In addition, we show for the first time that the ocean subsurface within 301-700 m experienced a net cooling, indicative of another instance of variability in the natural ocean. Furthermore, the ocean layer of 701-1500 m has experienced significant warming.

Effect of Climate Extremes, Seasonal Change, and Agronomic Practices on Measured Evapotranspiration and CO2 Exchange in Sacramento-San Joaquin River Delta Alfalfa Fields

NASA Astrophysics Data System (ADS)

Clay, J.; Kent, E. R.; Leinfelder-Miles, M.; Paw U, K. T.; Little, C.; Lambert, J. J.

2017-12-01

Evapotranspiration and CO2 exchange was measured in five alfalfa fields in the Sacramento-San Joaquin River Delta region from 2016 to 2017 using eddy covariance and surface renewal methods. Seasonal changes of evapotranspiration and CO2 fluxes were compared between 2016, a drought year, and 2017, a high rainfall year. Additionally, changes in evapotranspiration and CO2 flux were investigated across various agronomic considerations, such as irrigation methods (border-check flood and sub-surface), stand life, and herbicide programs. Components of the energy balance, including net radiation, latent heat, ground heat flux, and sensible heat, were evaluated considering correlations to wind speed measured by three sonic anemometers, irrigation frequency, and crop cutting cycle. Comparisons between two different types of radiometers were also carried out. Under drought conditions, we observed higher amounts of evapotranspiration in a field having a stand life of less than two years of age compared to older stands, and in a sub-surface irrigated field compared to flood irrigated fields.

Thermal management of an unconsolidated shallow urban groundwater body

NASA Astrophysics Data System (ADS)

Epting, J.; Händel, F.; Huggenberger, P.

2013-05-01

This study presents the development of tools for the sustainable thermal management of a shallow unconsolidated urban groundwater body in the city of Basel (Switzerland). The concept of the investigations is based on (1) a characterization of the present thermal state of the urban groundwater body, and (2) the evaluation of potential mitigation measures for the future thermal management of specific regions within the groundwater body. The investigations focus on thermal processes down-gradient of thermal groundwater use, effects of heated buildings in the subsurface as well as the thermal influence of river-groundwater interaction. Investigation methods include (1) short- and long-term data analysis, (2) high-resolution multilevel groundwater temperature monitoring, as well as (3) 3-D numerical groundwater flow and heat transport modeling and scenario development. The combination of these methods allows for the quantifying of the thermal influences on the investigated urban groundwater body, including the influences of thermal groundwater use and heated subsurface constructions. Subsequently, first implications for management strategies are discussed, including minimizing further groundwater temperature increase, targeting "potential natural" groundwater temperatures for specific aquifer regions and exploiting the thermal potential.

Subsurface application enhances benefits of manure redistribution

USDA-ARS?s Scientific Manuscript database

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

Nutrient loss in leachate and surface runoff from surface-broadcast and subsurface-banded broiler litter.

PubMed

Lamba, Jasmeet; Srivastava, Puneet; Way, Thomas R; Sen, Sumit; Wood, C Wesley; Yoo, Kyung H

2013-09-01

Subsurface band application of poultry litter has been shown to reduce the transport of nutrients from fields in surface runoff compared with conventional surface broadcast application. Little research has been conducted to determine the effects of surface broadcast application and subsurface banding of litter on nutrients in leachate. Therefore, a field experiment was conducted to determine the effects of subsurface band application and surface broadcast application of poultry litter on nutrient losses in leachate. Zero-tension pan and passive capillary fiberglass wick lysimeters were installed in situ 50 cm beneath the soil surface of an established tall fescue ( Schreb.) pasture on a sandy loam soil. The treatments were surface broadcast and subsurface-banded poultry litter at 5 Mg ha and an unfertilized control. Results of the rainfall simulations showed that the concentrations of PO-P and total phosphorus (TP) in leachate were reduced by 96 and 37%, respectively, in subsurface-banded litter treatment compared with the surface-applied litter treatment. There was no significant difference in PO-P concentration between control and subsurface-banded litter treatment in leachate. The trend in the loading of nutrients in leachate was similar to the trend in concentration. Concentration and loading of the nutrients (TP, PO-P, NH-N, and NO-N) in runoff from the subsurface-banded treatment were significantly less than for the surface-applied treatment and were similar to those from control plots. These results show that, compared with conventional surface broadcast application of litter, subsurface band application of litter can greatly reduce loss of P in surface runoff and leachate. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Fiber Optic Thermographic Detection of Flaws in Composites

NASA Technical Reports Server (NTRS)

Wu, Meng-Chou; Winfree, William P.

2009-01-01

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

Micrometeorological and Soil Data for Calculating Evapotranspiration for Rainier Mesa, Nevada Test Site, Nevada, 2002-05

USGS Publications Warehouse

DeMeo, Guy A.; Flint, Alan L.; Laczniak, Randell J.; Nylund, Walter E.

2006-01-01

Micrometeorological and soil-moisture data were collected at two instrumented sites on Rainier Mesa at the Nevada Test Site, January 1, 2002 - August 23, 2005. Data collected at each site include net radiation, air temperature, and relative humidity at two heights; wind speed and direction; subsurface soil heat flux; subsurface soil temperature; volumetric soil water; and matric water potential. These data were used to estimate 20-minute average and daily average evapotranspiration values. The data presented in this report are collected and calculated evapotranspiration rates.

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

NASA Technical Reports Server (NTRS)

Cuda, Vincent; Gaffney, Richard L

2008-01-01

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

Long-term predictions of minewater geothermal systems heat resources

NASA Astrophysics Data System (ADS)

Harcout-Menou, Virginie; de ridder, fjo; laenen, ben; ferket, helga

2014-05-01

Abandoned underground mines usually flood due to the natural rise of the water table. In most cases the process is relatively slow giving the mine water time to equilibrate thermally with the the surrounding rock massif. Typical mine water temperature is too low to be used for direct heating, but is well suited to be combined with heat pumps. For example, heat extracted from the mine can be used during winter for space heating, while the process could be reversed during summer to provide space cooling. Altough not yet widely spread, the use of low temperature geothermal energy from abandoned mines has already been implemented in the Netherlands, Spain, USA, Germany and the UK. Reliable reservoir modelling is crucial to predict how geothermal minewater systems will react to predefined exploitation schemes and to define the energy potential and development strategy of a large-scale geothermal - cold/heat storage mine water systems. However, most numerical reservoir modelling software are developed for typical environments, such as porous media (a.o. many codes developed for petroleum reservoirs or groundwater formations) and cannot be applied to mine systems. Indeed, mines are atypical environments that encompass different types of flow, namely porous media flow, fracture flow and open pipe flow usually described with different modelling codes. Ideally, 3D models accounting for the subsurface geometry, geology, hydrogeology, thermal aspects and flooding history of the mine as well as long-term effects of heat extraction should be used. A new modelling approach is proposed here to predict the long-term behaviour of Minewater geothermal systems in a reactive and reliable manner. The simulation method integrates concepts for heat and mass transport through various media (e.g., back-filled areas, fractured rock, fault zones). As a base, the standard software EPANET2 (Rossman 1999; 2000) was used. Additional equations for describing heat flow through the mine (both through open pipes and from the rock massif) have been implemented. Among others, parametric methods are used to bypass some shortcomings in the physical models used for the subsurface. The advantage is that the complete geometry of the mine workings can be integrated and that computing is fast enough to allow implementing and testing several scenarios (e.g. contributions from fault zones, different assumptions about the actual status of shafts, drifts and mined out areas) in an efficient way (Ferket et al., 2011). EPANET allows to incorporate the full complexity of the subsurface mine structure. As a result, the flooded mine is considered as a network of pipes, each with a custom-defined diameter, length and roughness.

Multiphase, multicomponent simulations and experiments of reactive flow, relevant for combining geologic CO2 sequestration with geothermal energy capture

NASA Astrophysics Data System (ADS)

Saar, Martin O.

2011-11-01

Understanding the fluid dynamics of supercritical carbon dioxide (CO2) in brine- filled porous media is important for predictions of CO2 flow and brine displacement during geologic CO2 sequestration and during geothermal energy capture using sequestered CO2 as the subsurface heat extraction fluid. We investigate multiphase fluid flow in porous media employing particle image velocimetry experiments and lattice-Boltzmann fluid flow simulations at the pore scale. In particular, we are interested in the motion of a drop (representing a CO2 bubble) through an orifice in a plate, representing a simplified porous medium. In addition, we study single-phase/multicomponent reactive transport experimentally by injecting water with dissolved CO2 into rocks/sediments typically considered for CO2 sequestration to investigate how resultant fluid-mineral reactions modify permeability fields. Finally, we investigate numerically subsurface CO2 and heat transport at the geologic formation scale.

Regional geothermal exploration in Egypt

NASA Technical Reports Server (NTRS)

Morgan, P.; Boulos, F. K.; Swanberg, C. A.

1983-01-01

A study is presented of the evaluation of the potential geothermal resources of Egypt using a thermal gradient/heat flow technique and a groundwater temperature/chemistry technique. Existing oil well bottom-hole temperature data, as well as subsurface temperature measurements in existing boreholes, were employed for the thermal gradient/heat flow investigation before special thermal gradient holes were drilled. The geographic range of the direct subsurface thermal measurements was extended by employing groundwater temperature and chemistry data. Results show the presence of a regional thermal high along the eastern margin of Egypt with a local thermal anomaly in this zone. It is suggested that the sandstones of the Nubian Formation may be a suitable reservoir for geothermal fluids. These findings indicate that temperatures of 150 C or higher may be found in this reservoir in the Gulf of Suez and Red Sea coastal zones where it lies at a depth of 4 km and deeper.

OVERVIEW -- SUBSURFACE PROTECTION AND REMEDIATION DIVISION

EPA Science Inventory

NRMRL's Subsurface Protection and Remediation Division located in Ada, Oklahoma, conducts EPA-investigator led laboratory and field research to provide the scientific basis to support the development of strategies and technologies to protect and restore ground and surface water q...

Measurements of Low-Frequency Acoustic Attenuation in Soils.

DTIC Science & Technology

1994-10-13

Engineering Research Laboratory to design an acoustic subsurface imaging system, a set of experiments was conducted in which the attenuation and the velocity...support of the U.S. Army Construction Engineering Research Laboratory’s efforts to design an acoustic subsurface imaging system which would ideally be...of acoustic waves such as those generated by a subsurface imaging system. An experiment reported in the literature characterized the acoustic

Treating nahcolite containing formations and saline zones

DOEpatents

Vinegar, Harold J

2013-06-11

A method for treating a nahcolite containing subsurface formation includes removing water from a saline zone in or near the formation. The removed water is heated using a steam and electricity cogeneration facility. The heated water is provided to the nahcolite containing formation. A fluid is produced from the nahcolite containing formation. The fluid includes at least some dissolved nahcolite. At least some of the fluid is provided to the saline zone.

The significance of "geothermal microzonation" for the correct planning of low-grade source geothermal systems

NASA Astrophysics Data System (ADS)

Viccaro, Marco; Pezzino, Antonino; Belfiore, Giuseppe Maria; Campisano, Carlo

2016-04-01

Despite the environmental-friendly energy systems are solar thermal technologies, photovoltaic and wind power, other advantageous technologies exist, although they have not found wide development in countries such as Italy. Given the almost absent environmental impact and the rather favorable cost/benefit ratio, low-enthalpy geothermal systems are, however, likely to be of strategic importance also in Italy during the next years. The importance of geology for a sustainable exploitation of the ground through geothermal systems from low-grade sources is becoming paramount. Specifically, understanding of the lithological characteristics of the subsurface along with structures and textures of rocks is essential for a correct planning of the probe/geo-exchanger field and their associated ground source heat pumps. The complex geology of Eastern Sicily (Southern Italy), which includes volcanic, sedimentary and metamorphic units over limited extension, poses the question of how thermal conductivity of rocks is variable at the scale of restricted areas (even within the same municipality). This is the innovative concept of geothermal microzonation, i.e., how variable is the geothermal potential as a function of geology at the microscale. Some pilot areas have been therefore chosen to test how the geological features of the subsurface can influence the low-enthalpy geothermal potential of an area. Our geologically based evaluation and micro-zonation of the low-grade source geothermal potential of the selected areas have been verified to be fundamental for optimization of all the main components of a low-enthalpy geothermal system. Saving realization costs and limiting the energy consumption through correct sizing of the system are main ambitions to have sustainable development of this technology with intensive utilization of the subsurface. The variegated territory of countries such as Italy implies that these goals can be only reached if, primarily, the geological features of the shallow subsurface (i.e., chemical-physical characteristics of rocks and fluids of the first 100 m below the ground) are appropriately constrained.

Low signal-to-noise FDEM in-phase data: Practical potential for magnetic susceptibility modelling

NASA Astrophysics Data System (ADS)

Delefortrie, Samuël; Hanssens, Daan; De Smedt, Philippe

2018-05-01

In this paper, we consider the use of land-based frequency-domain electromagnetics (FDEM) for magnetic susceptibility modelling. FDEM data comprises both out-of-phase and in-phase components, which can be related to the electrical conductivity and magnetic susceptibility of the subsurface. Though applying the FDEM method to obtain information on the subsurface conductivity is well established in various domains (e.g. through the low induction number approximation of subsurface apparent conductivity), the potential for susceptibility mapping is often overlooked. Especially given a subsurface with a low magnetite and maghemite content (e.g. most sedimentary environments), it is generally assumed that susceptibility is negligible. Nonetheless, the heterogeneity of the near surface and the impact of anthropogenic disturbances on the soil can cause sufficient variation in susceptibility for it to be detectable in a repeatable way. Unfortunately, it can be challenging to study the potential for susceptibility mapping due to systematic errors, an often poor low signal-to-noise ratio, and the intricacy of correlating in-phase responses with subsurface susceptibility and conductivity. Alongside use of an accurate forward model - accounting for out-of-phase/in-phase coupling - any attempt at relating the in-phase response with subsurface susceptibility requires overcoming instrument-specific limitations that burden the real-world application of FDEM susceptibility mapping. Firstly, the often erratic and drift-sensitive nature of in-phase responses calls for relative data levelling. In addition, a correction for absolute levelling offsets may be equally necessary: ancillary (subsurface) susceptibility data can be used to assess the importance of absolute in-phase calibration though hereby accurate in-situ data is required. To allow assessing the (importance of) in-phase calibration alongside the potential of FDEM data for susceptibility modelling, we consider an experimental test case whereby the in-phase responses of a multi-receiver FDEM instrument are calibrated through downhole susceptibility data. Our results show that, while it is possible to derive approximate susceptibility profiles from FDEM data, robust quantitative analysis hinges on appropriate calibration of the responses.

Effects of subsurface aeration and trinexapac-ethyl application on soil microbial communities in a creeping bentgrass putting green

USGS Publications Warehouse

Feng, Y.; Stoeckel, D.M.; Van Santen, E.; Walker, R.H.

2002-01-01

The sensitivity of creeping bentgrass (Agrostis palustris Huds.) to the extreme heat found in the southeastern United States has led to the development of new greens-management methods. The purpose of this study was to examine the effects of subsurface aeration and growth regulator applications on soil microbial communities and mycorrhizal colonization rates in a creeping bentgrass putting green. Two cultivars (Crenshaw and Penncross), a growth regulator (trinexapacethyl), and subsurface aeration were evaluated in cool and warm seasons. Total bacterial counts were higher in whole (unsieved) soils than in sieved soils, indicating a richer rhizosphere soil environment. Mycorrhizal infection rates were higher in trinexapac-ethyl (TE) treated plants. High levels of hyphal colonization and relatively low arbuscule and vesicle occurrence were observed. Principal components analysis of whole-soil fatty acid methyl ester (FAME) profiles indicated that warm-season microbial populations in whole and sieved soils had similar constituents, but the populations differed in the cool season. FAME profiles did not indicate that subsurface aeration and TE application affected soil microbial community structure. This is the first reported study investigating the influences of subsurface aeration and TE application on soil microorganisms in a turfgrass putting green soil.

Methods of hydrotreating a liquid stream to remove clogging compounds

DOEpatents

Minderhoud, Johannes Kornelis [Amsterdam, NL; Nelson, Richard Gene [Katy, TX; Roes, Augustinus Wilhelmus Maria [Houston, TX; Ryan, Robert Charles [Houston, TX; Nair, Vijay [Katy, TX

2009-09-22

A method includes producing formation fluid from a subsurface in situ heat treatment process. The formation fluid is separated to produce a liquid stream and a gas stream. At least a portion of the liquid stream is provided to a hydrotreating unit. At least a portion of selected in situ heat treatment clogging compositions in the liquid stream are removed to produce a hydrotreated liquid stream by hydrotreating at least a portion of the liquid stream at conditions sufficient to remove the selected in situ heat treatment clogging compositions.

A comparison of quality of present-day heat flow obtained from BHTs, Horner Plots of Malay Basin

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

Waples, D.W.; Mahadir, R.

1994-07-01

Reconciling temperature data obtained from measurement of single BHT, multiple BHT at a single depth, RFTs, and DSTs, is very difficult. Quality of data varied widely, however DST data were assumed to be most reliable. Data from 87 wells was used in this study, but only 47 wells have DST data. BASINMOD program was used to calculate the present-day heat flow, using measured thermal conductivity and calibrated against the DST data. The heat flows obtained from the DST data were assumed to be correct and representative throughout the basin. Then, heat flows using (1) uncorrected RFT data, (2) multiple BHTmore » data corrected by the Horner plot method, and (3) single BHT values corrected upward by a standard 10% were calculated. All of these three heat-flow populations had identically standard deviations to that for the DST data, but with significantly lower mean values. Correction factors were calculated to give each of the three erroneous populations the same mean value as the DST population. Heat flows calculated from RFT data had to be corrected upward by a factor of 1.12 to be equivalent to DST data; Horner plot data corrected by a factor of 1.18, and single BHT data by a factor of 1.2. These results suggest that present-day subsurface temperatures using RFT, Horner plot, and BHT data are considerably lower than they should be. The authors suspect qualitatively similar results would be found in other areas. Hence, they recommend significant corrections be routinely made until local calibration factors are established.« less

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

NASA Astrophysics Data System (ADS)

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 <15% for thermal conductivity and thermal diffusivity, and of <10% for specific heat capacity. Comparison of predicted and benchmark laboratory thermal conductivity from deep boreholes of the Norwegian-Danish Basin, the North German Basin, and the Molasse Basin results in 3 to 5% larger uncertainties with regard to the test data set. With regard to temperature models, the use of calculated TC borehole profiles approximate measured temperature logs with an error of <3°C along a 4 km deep profile. A benchmark comparison for thermal diffusivity and specific heat capacity is pending. 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

Upper ocean climate of the Eastern Mediterranean Sea during the Holocene Insolation Maximum - a model study

NASA Astrophysics Data System (ADS)

Adloff, F.; Mikolajewicz, U.; Kucera, M.; Grimm, R.; Maier-Reimer, E.; Schmiedl, G.; Emeis, K.

2011-05-01

Nine thousand years ago, the Northern Hemisphere experienced enhanced seasonality caused by an orbital configuration with a minimum of the precession index. To assess the impact of the "Holocene Insolation Maximum" (HIM) on the Mediterranean Sea, we use a regional ocean general circulation model forced by atmospheric input derived from global simulations. A stronger seasonal cycle is simulated in the model, which shows a relatively homogeneous winter cooling and a summer warming with well-defined spatial patterns, in particular a subsurface warming in the Cretan and Western Levantine areas. The comparison between the SST simulated for the HIM and the reconstructions from planktonic foraminifera transfer functions shows a poor agreement, especially for summer, when the vertical temperature gradient is strong. However, a reinterpretation of the reconstructions is proposed, to consider the conditions throughout the upper water column. Such a depth-integrated approach accounts for the vertical range of preferred habitat depths of the foraminifera used for the reconstructions and strongly improves the agreement between modelled and reconstructed temperature signal. The subsurface warming is recorded by both model and proxies, with a light shift to the south in the model results. The mechanisms responsible for the peculiar subsurface pattern are found to be a combination of enhanced downwelling and wind mixing due to strengthened Etesian winds, and enhanced thermal forcing due to the stronger summer insolation in the Northern Hemisphere. Together, these processes induce a stronger heat transfer from the surface to the subsurface during late summer in the Western Levantine; this leads to an enhanced heat piracy in this region.

WESTERN ENERGY RESOURCES AND THE ENVIRONMENT: GEOTHERMAL ENERGY

EPA Science Inventory

Geothermal energy--from subsurface heat sources created by the underlying geologic configuration of the earth--is addressed, from an environmental research and development perspective. The report covers various geothermal energy systems, which serve as present or potential energy...

Nontoxic chemical process for in situ permeability enhancement and accelerated decontamination of fine-grain subsurface sediments

DOEpatents

Kansa, E.J.; Wijesinghe, A.M.; Viani, B.E.

1997-01-14

The remediation of heterogeneous subsurfaces is extremely time consuming and expensive with current and developing technologies. Although such technologies can adequately remove contaminants in the high hydraulic conductivity, coarse-grained sediments, they cannot access the contaminated low hydraulic conductivity fine-grained sediments. The slow bleed of contaminants from the fine-grained sediments is the primary reason why subsurface remediation is so time-consuming and expensive. This invention addresses the problem of remediating contaminated fine-grained sediments. It is intended that, in the future, a heterogeneous site be treated by a hybrid process that first remediates the high hydraulic conductivity, coarse-grained sediments, to be followed by the process, described in this invention, to treat the contaminated low hydraulic conductivity fine-grained sediments. The invention uses cationic flocculants and organic solvents to collapse the swelling negative double layer surrounding water saturated clay particles, causing a flocculated, cracked clay structure. The modification of the clay fabric in fine-grained sediments dramatically increases the hydraulic conductivity of previously very tight clays many orders of magnitude. 8 figs.

Nontoxic chemical process for in situ permeability enhancement and accelerated decontamination of fine-grain subsurface sediments

DOEpatents

Kansa, Edward J.; Wijesinghe, Ananda M.; Viani, Brian E.

1997-01-01

The remediation of heterogeneous subsurfaces is extremely time consuming and expensive with current and developing technologies. Although such technologies can adequately remove contaminants in the high hydraulic conductivity, coarse-grained sediments, they cannot access the contaminated low hydraulic conductivity fine-grained sediments. The slow bleed of contaminants from the fine-grained sediments is the primary reason why subsurface remediation is so time-consuming and expensive. This invention addresses the problem of remediating contaminated fine-grained sediments. It is intended that, in the future, a heterogeneous site be treated by a hybrid process that first remediates the high hydraulic conductivity, coarse-grained sediments, to be followed by the process, described in this invention, to treat the contaminated low hydraulic conductivity fine-grained sediments. The invention uses cationic flocculents and organic solvents to collapse the swelling negative double layer surrounding water saturated clay particles, causing a flocculated, cracked clay structure. The modification of the clay fabric in fine-grained sediments dramatically increases the hydraulic conductivity of previously very tight clays many orders of magnitude.

Feasibility study of a swept frequency electromagnetic probe (SWEEP) using inductive coupling for the determination of subsurface conductivity of the earth and water prospecting in arid regions

NASA Technical Reports Server (NTRS)

Latorraca, G. A.; Bannister, L. H.

1974-01-01

Techniques developed for electromagnetic probing of the lunar interior, and techniques developed for the generation of high power audio frequencies were combined to make practical a magnetic inductive coupling system for the rapid measurement of ground conductivity profiles which are helpful when prospecting for the presence and quality of subsurface water. A system which involves the measurement of the direction, intensity, and time phase of the magnetic field observed near the surface of the earth at a distance from a horizontal coil energized so as to create a field that penetrates the earth was designed and studied to deduce the conductivity and stratification of the subsurface. Theoretical studies and a rudimentary experiment in an arid region showed that the approach is conceptually valid and that this geophysical prospecting technique can be developed for the economical exploration of subterranean water resources.

Refining Southern California Geotherms Using Seismologic, Geologic, and Petrologic Constraints

NASA Astrophysics Data System (ADS)

Thatcher, W. R.; Chapman, D. S.; Allam, A. A.; Williams, C. F.

2017-12-01

Lithospheric deformation in tectonically active regions depends on the 3D distribution of rheology, which is in turn critically controlled by temperature. Under the auspices of the Southern California Earthquake Center (SCEC) we are developing a 3D Community Thermal Model (CTM) to constrain rheology and so better understand deformation processes within this complex but densely monitored and relatively well-understood region. The San Andreas transform system has sliced southern California into distinct blocks, each with characteristic lithologies, seismic velocities and thermal structures. Guided by the geometry of these blocks we use more than 250 surface heat-flow measurements to define 13 geographically distinct heat flow regions (HFRs). Model geotherms within each HFR are constrained by averages and variances of surface heat flow q0 and the 1D depth distribution of thermal conductivity (k) and radiogenic heat production (A), which are strongly dependent on rock type. Crustal lithologies are not always well known and we turn to seismic imaging for help. We interrogate the SCEC Community Velocity Model (CVM) to determine averages and variances of Vp, Vs and Vp/Vs versus depth within each HFR. We bound (A, k) versus depth by relying on empirical relations between seismic wave speed and rock type and laboratory and modeling methods relating (A, k) to rock type. Many 1D conductive geotherms for each HFR are allowed by the variances in surface heat flow and subsurface (A, k). An additional constraint on the lithosphere temperature field is provided by comparing lithosphere-asthenosphere boundary (LAB) depths identified seismologically with those defined thermally as the depth of onset of partial melting. Receiver function studies in Southern California indicate LAB depths that range from 40 km to 90 km. Shallow LAB depths are correlated with high surface heat flow and deep LAB with low heat flow. The much-restricted families of geotherms that intersect peridotite solidi at the seismological LAB depth in each region require that LAB temperatures lie between 1050 to 1250˚ C, a range that is consistent with a hydrous rather than anhydrous mantle below Southern California.

A reference data set of hillslope rainfall-runoff response, Panola Mountain Research Watershed, United States

USGS Publications Warehouse

Tromp-van, Meerveld; James, A.L.; McDonnell, Jeffery J.; Peters, N.E.

2008-01-01

Although many hillslope hydrologic investigations have been conducted in different climate, topographic, and geologic settings, subsurface stormflow remains a poorly characterized runoff process. Few, if any, of the existing data sets from these hillslope investigations are available for use by the scientific community for model development and validation or conceptualization of subsurface stormflow. We present a high-resolution spatial and temporal rainfall-runoff data set generated from the Panola Mountain Research Watershed trenched experimental hillslope. The data set includes surface and subsurface (bedrock surface) topographic information and time series of lateral subsurface flow at the trench, rainfall, and subsurface moisture content (distributed soil moisture content and groundwater levels) from January to June 2002. Copyright 2008 by the American Geophysical Union.

Modeling subsurface stormflow initiation in low-relief landscapes

NASA Astrophysics Data System (ADS)

Hopp, Luisa; Vaché, Kellie B.; Rhett Jackson, C.; McDonnell, Jeffrey J.

2015-04-01

Shallow lateral subsurface flow as a runoff generating mechanism at the hillslope scale has mostly been studied in steeper terrain with typical hillside angles of 10 - 45 degrees. These studies have shown that subsurface stormflow is often initiated at the interface between a permeable upper soil layer and a lower conductivity impeding layer, e.g. a B horizon or bedrock. Many studies have identified thresholds of event size and soil moisture states that need to be exceeded before subsurface stormflow is initiated. However, subsurface stormflow generation on low-relief hillslopes has been much less studied. Here we present a modeling study that investigates the initiation of subsurface stormflow on low-relief hillslopes in the Upper Coastal Plain of South Carolina, USA. Hillslopes in this region typically have slope angles of 2-5 degrees. Topsoils are sandy, underlain by a low-conductivity sandy clay loam Bt horizon. Subsurface stormflow has only been intercepted occasionally in a 120 m long trench, and often subsurface flow was not well correlated with stream signals, suggesting a disconnect between subsurface flow on the hillslopes and stream flow. We therefore used a hydrologic model to better understand which conditions promote the initiation of subsurface flow in this landscape, addressing following questions: Is there a threshold event size and soil moisture state for producing lateral subsurface flow? What role does the spatial pattern of depth to the impeding clay layer play for subsurface stormflow dynamics? We reproduced a section of a hillslope, for which high-resolution topographic data and depth to clay measurements were available, in the hydrologic model HYDRUS-3D. Soil hydraulic parameters were based on experimentally-derived data. The threshold analysis was first performed using hourly climate data records for 2009-2010 from the study site to drive the simulation. For this period also trench measurements of subsurface flow were available. In addition, we also ran a longer-term simulation, using daily climate data for a nine year period to include more variable climate conditions in the threshold analysis. The model captured the observed subsurface flow instances very well. The threshold analysis indicated that the occurrence of subsurface stormflow uncommon, with a large proportion of the water perching above the clay layer percolating vertically into the clay layer. Event sizes of approximately 70-80 mm were required for initiating subsurface stormflow. The hourly data from 2009-2010 was subsequently used to test if the actual spatial distribution of depth to clay is a major control for the occurrence and magnitude of lateral subsurface flow. Results suggest that in this low-relief landscape also a spatially uniform mean depth to clay reproduces well the hydrologic behavior.

Exploration of the enhanced geothermal system (EGS) potential of crystalline rocks for district heating (Elbe Zone, Saxony, Germany)

NASA Astrophysics Data System (ADS)

Förster, Andrea; Förster, Hans-Jürgen; Krentz, Ottomar

2018-01-01

This paper addresses aspects of a baseline geothermal exploration of the thermally quiescent Elbe Zone (hosting the cities of Meissen and Dresden) for a potential deployment of geothermal heat in municipal heating systems. Low-permeable to impermeable igneous and metamorphic rocks constitute the major rock types at depth, implying that an enhanced geothermal system needs to be developed by creating artificial flow paths for fluids to enhance the heat extraction from the subsurface. The study includes the development of geological models for two areas on the basis of which temperature models are generated at upper crustal scale. The models are parameterized with laboratory-measured rock thermal properties (thermal conductivity k, radiogenic heat production H). The uncertainties of modelled temperature caused by observed variations of k and H and inferred mantle heat flow are assessed. The study delineates highest temperatures within the intermediate (monzonite/syenite unit) and mafic rocks (diorite/monzodiorite unit) forming the deeper portions of the Meissen Massif and, specifically for the Dresden area, also within the low-metamorphic rocks (slates/phyllites/quartzites) of the Elbtalschiefergebirge. Boreholes 3-4 km deep need to be drilled to reach the envisioned economically favourable temperatures of 120 °C. The metamorphic and mafic rocks exhibit low concentrations of U and Th, thus being advantageous for a geothermal use. For the monzonite/syenite unit of high heat production ( 6 µW m-3) in the Meissen Massif, the mobilization of Th and U into the geothermal working fluid is assumed to be minor, although their various radioactive decay products will be omnipresent during geothermal use.

DESIGN OF A SURFACTANT REMEDIATION FIELD DEMONSTRATION BASED ON LABORATORY AND MODELINE STUDIES

EPA Science Inventory

Surfactant-enhanced subsurface remediation is being evaluated as an innovative technology for expediting ground-water remediation. This paper reports on laboratory and modeling studies conducted in preparation for a pilot-scale field test of surfactant-enhanced subsurface remedia...

Models Show Subsurface Cracking May Complicate Groundwater Cleanup at Hazardous Waste Sites

EPA Science Inventory

Chlorinated solvents like trichloroethylene contaminate groundwater at numerous sites nationwide. This modeling study, conducted at the Air Force Institute of Technology, shows that subsurface cracks, either natural or due to the presence of the contaminant itself, may result in...

Ground geophysical study of the Buckeye mine tailings, Boulder watershed, Montana

USGS Publications Warehouse

McDougal, Robert R.; Smith, Bruce D.

2000-01-01

The Buckeye mine site is located in the Boulder River watershed along Basin Creek, in northern Jefferson County, Montana. This project is part of the Boulder River watershed Abandoned Mine Lands Initiative, and is a collaborative effort between the U.S. Geological Survey and Bureau of Land Management in the U.S. Department of the Interior, and the U.S. Forest Service in the U.S. Department of Agriculture. The site includes a large flotation milltailing deposit, which extends to the stream and meadows below the mine. These tailings contain elevated levels of metals, such as silver, cadmium, copper, lead, and zinc. Metal-rich fluvial tailings containing these metals, are possible sources of ground and surface water contamination. Geophysical methods were used to characterize the sediments at the Buckeye mine site. Ground geophysical surveys, including electromagnetics, DC resistivity, and total field magnetic methods, were used to delineate anomalies that probably correlate with subsurface metal contamination. Subsurface conductivity was mapped using EM-31 and EM-34 terrain conductivity measuring systems. The conductivity maps represent variation of concentration of dissolved solids in the subsurface from a few meters, to an approximate depth of 30 meters. Conductive sulfides several centimeters thick were encountered in a shallow trench, dug in an area of very high conductivity, at a depth of approximately 1 to1.5 meters. Laboratory measurements of samples of the sulfide layers show the conductivity is on the order of 1000 millisiemens. DC resistivity soundings were used to quantify subsurface conductivity variations and to estimate the depth to bedrock. Total field magnetic measurements were used to identify magnetic metals in the subsurface. The EM surveys identified several areas of relatively high conductivity and detected a conductive plume extending to the southwest, toward the stream. This plume correlates well with the potentiometric surface and direction of ground water flow, and with water quality data from monitoring wells in and around the tailings. The electrical geophysical data suggests there has been vertical migration of high dissolved solids. A DC sounding made on a nearby granite outcrop to the north of the mine showed that the shallow conductivity is on the order of 5 millisiemens/m. Granite underlying the mine tailings, with similar electrical properties as the outcropping area, may be more than 30 meters deep.

How ice shelf morphology controls basal melting

NASA Astrophysics Data System (ADS)

Little, Christopher M.; Gnanadesikan, Anand; Oppenheimer, Michael

2009-12-01

The response of ice shelf basal melting to climate is a function of ocean temperature, circulation, and mixing in the open ocean and the coupling of this external forcing to the sub-ice shelf circulation. Because slope strongly influences the properties of buoyancy-driven flow near the ice shelf base, ice shelf morphology plays a critical role in linking external, subsurface heat sources to the ice. In this paper, the slope-driven dynamic control of local and area-integrated melting rates is examined under a wide range of ocean temperatures and ice shelf shapes, with an emphasis on smaller, steeper ice shelves. A 3-D numerical ocean model is used to simulate the circulation underneath five idealized ice shelves, forced with subsurface ocean temperatures ranging from -2.0°C to 1.5°C. In the sub-ice shelf mixed layer, three spatially distinct dynamic regimes are present. Entrainment of heat occurs predominately under deeper sections of the ice shelf; local and area-integrated melting rates are most sensitive to changes in slope in this "initiation" region. Some entrained heat is advected upslope and used to melt ice in the "maintenance" region; however, flow convergence in the "outflow" region limits heat loss in flatter portions of the ice shelf. Heat flux to the ice exhibits (1) a spatially nonuniform, superlinear dependence on slope and (2) a shape- and temperature-dependent, internally controlled efficiency. Because the efficiency of heat flux through the mixed layer decreases with increasing ocean temperature, numerical simulations diverge from a simple quadratic scaling law.

Method of producing strained-layer semiconductor devices via subsurface-patterning

DOEpatents

Dodson, Brian W.

1993-01-01

A method is described for patterning subsurface features in a semiconductor device, wherein the semiconductor device includes an internal strained layer. The method comprises creating a pattern of semiconductor material over the semiconductor device, the semiconductor material having a predetermined thickness which stabilizes areas of the strained semiconductor layer that lie beneath the pattern. Subsequently, a heating step is applied to the semiconductor device to cause a relaxation in areas of the strained layer which do not lie beneath the semiconductor material pattern, whereby dislocations result in the relaxed areas and impair electrical transport therethrough.

Heat storage in the Hettangian aquifer in Berlin - results from a column experiment

NASA Astrophysics Data System (ADS)

Milkus, Chri(Sch)augott

2015-04-01

Aquifer Thermal Energy Storage (ATES) is a sustainable alternative for storage and seasonal availability of thermal energy. However, its impact on the subsurface flow regime is not well known. In Berlin (Germany), the Jurassic (Hettangian) sandstone aquifer with highly mineralized groundwater (TDS 27 g/L) is currently used for heat storage. The aim of this study was to examine the hydrogeochemical changes that are caused by the induced temperature shift and its effects on the hydraulic permeability of the aquifer. Column experiments were conducted, in which stainless steel columns were filled with sediment from the aquifer and flushed with native groundwater for several weeks. The initial temperature of the experiment was 20°C, comparable to the in-situ conditions within the aquifer. After reaching equilibrium between sediment and water, the temperature was increased to simulate heating of the aquifer. During the experiment, physical and chemical parameters (pH, ORP, dissolved oxygen and dissolved carbon dioxide) were measured at the outflow of the column and the effluent water was sampled. Using a Scanning Electron Microscope, the deposition of precipitated minerals and biofilm on sediment grains was analyzed. Changes in hydraulic properties of the sediment were studied by the use of tracer tests with Uranin.

EFFECT OF FENTON'S REAGENT ON SUBSURFACE MICROBIOLOGY AND BIODEGRADATION CAPACITY

EPA Science Inventory

Microcosm studies were conducted to determine the effect of Fenton's reagent on subsurface microbiology and biodegradation capacity in a DNAPL (PCE/TCE) contaminated aquifer previously treated with the reagent. Groundwater pH declined from 5 to 2.4 immediately after the treatmen...

Thermal Imaging of Subsurface Coal Fires by means of an Unmanned Aerial Vehicle (UAV) in the Autonomous Province Xinjiang, PRC

NASA Astrophysics Data System (ADS)

Vasterling, Margarete; Schloemer, Stefan; Fischer, Christian; Ehrler, Christoph

2010-05-01

Spontaneous combustion of coal and resulting coal fires lead to very high temperatures in the subsurface. To a large amount the heat is transferred to the surface by convective and conductive transport inducing a more or less pronounced thermal anomaly. During the past decade satellite-based infrared-imaging (ASTER, MODIS) was the method of choice for coal fire detection on a local and regional scale. However, the resolution is by far too low for a detailed analysis of single coal fires which is essential prerequisite for corrective measures (i.e. fire fighting) and calculation of carbon dioxide emission based on a complex correlation between energy release and CO2 generation. Consequently, within the framework of the Sino-German research project "Innovative Technologies for Exploration, Extinction and Monitoring of Coal Fires in Northern China", a new concept was developed and successfully tested. An unmanned aerial vehicle (UAV) was equipped with a lightweight camera for thermografic (resolution 160 by 120 pixel, dynamic range -20 to 250°C) and for visual imaging. The UAV designed as an octocopter is able to hover at GPS controlled waypoints during predefined flight missions. The application of a UAV has several advantages. Compared to point measurements on the ground the thermal imagery quickly provides the spatial distribution of the temperature anomaly with a much better resolution. Areas otherwise not accessible (due to topography, fire induced cracks, etc.) can easily be investigated. The results of areal surveys on two coal fires in Xinjiang are presented. Georeferenced thermal and visual images were mosaicked together and analyzed. UAV-born data do well compared to temperatures measured directly on the ground and cover large areas in detail. However, measuring surface temperature alone is not sufficient. Simultaneous measurements made at the surface and in roughly 15cm depth proved substantial temperature gradients in the upper soil. Thus the temperature measured at the surface underestimates the energy emitted by the subsurface coal fire. In addition, surface temperature is strongly influenced by solar radiation and the prevailing ambient conditions (wind, temperature, humidity). As a consequence there is no simple correlation between surface and subsurface soil temperature. Efforts have been made to set up a coupled energy transport and energy balance model for the near surface considering thermal conduction, solar irradiation, thermal radiative energy and ambient temperature so far. The model can help to validate space-born and UAV-born thermal imagery and link surface to subsurface temperature but depends on in-situ measurements for input parameter determination and calibration. Results obtained so far strongly necessitate the integration of different data sources (in-situ / remote; point / area; local / medium scale) to obtain a reliable energy release estimation which is then used for coal fire characterization.

Subsurface Flow and Moisture Dynamics in Response to Swash Motions: Effects of Beach Hydraulic Conductivity and Capillarity

NASA Astrophysics Data System (ADS)

Geng, Xiaolong; Heiss, James W.; Michael, Holly A.; Boufadel, Michel C.

2017-12-01

A combined field and numerical study was conducted to investigate dynamics of subsurface flow and moisture response to waves in the swash zone of a sandy beach located on Cape Henlopen, DE. A density-dependent variably saturated flow model MARUN was used to simulate subsurface flow beneath the swash zone. Values of hydraulic conductivity (K) and characteristic pore size (α, a capillary fringe property) were varied to evaluate their effects on subsurface flow and moisture dynamics in response to swash motions in beach aquifers. The site-specific modeling results were validated against spatiotemporal measurements of moisture and pore pressure in the beach. Sensitivity analyses indicated that the hydraulic conductivity and capillary fringe thickness of the beach greatly influenced groundwater flow pathways and associated transit times in the swash zone. A higher value of K enhanced swash-induced seawater infiltration into the beach, thereby resulting in a faster expansion of a wedge of high moisture content induced by swash cycles, and a flatter water table mound beneath the swash zone. In contrast, a thicker capillary fringe retained higher moisture content near the beach surface, and thus, significantly reduced the available pore space for infiltration of seawater. This attenuated wave effects on pore water flow in the unsaturated zone of the beach. Also, a thicker capillary fringe enhanced horizontal flow driven by the larger-scale hydraulic gradient caused by tides.

Identification of subsurface structures using electromagnetic data and shape priors

NASA Astrophysics Data System (ADS)

Tveit, Svenn; Bakr, Shaaban A.; Lien, Martha; Mannseth, Trond

2015-03-01

We consider the inverse problem of identifying large-scale subsurface structures using the controlled source electromagnetic method. To identify structures in the subsurface where the contrast in electric conductivity can be small, regularization is needed to bias the solution towards preserving structural information. We propose to combine two approaches for regularization of the inverse problem. In the first approach we utilize a model-based, reduced, composite representation of the electric conductivity that is highly flexible, even for a moderate number of degrees of freedom. With a low number of parameters, the inverse problem is efficiently solved using a standard, second-order gradient-based optimization algorithm. Further regularization is obtained using structural prior information, available, e.g., from interpreted seismic data. The reduced conductivity representation is suitable for incorporation of structural prior information. Such prior information cannot, however, be accurately modeled with a gaussian distribution. To alleviate this, we incorporate the structural information using shape priors. The shape prior technique requires the choice of kernel function, which is application dependent. We argue for using the conditionally positive definite kernel which is shown to have computational advantages over the commonly applied gaussian kernel for our problem. Numerical experiments on various test cases show that the methodology is able to identify fairly complex subsurface electric conductivity distributions while preserving structural prior information during the inversion.

Ocean heat content and ocean energy budget: make better use of historical global subsurface temperature dataset

NASA Astrophysics Data System (ADS)

Cheng, L.; Zhu, J.

2016-02-01

Ocean heat content (OHC) change contributes substantially to global sea level rise, also is a key metric of the ocean/global energy budget, so it is a vital task for the climate research community to estimate historical OHC. While there are large uncertainties regarding its value, here we review the OHC calculation by using the historical global subsurface temperature dataset, and discuss the sources of its uncertainty. The presentation briefly introduces how to correct to the systematic biases in expendable bathythermograph (XBT) data, a alternative way of filling data gaps (which is main focus of this talk), and how to choose a proper climatology. A new reconstruction of historical upper (0-700 m) OHC change will be presented, which is the Institute of Atmospheric Physics (IAP) version of historical upper OHC assessment. The authors also want to highlight the impact of observation system change on OHC calculation, which could lead to bias in OHC estimates. Furthermore, we will compare the updated observational-based estimates on ocean heat content change since 1970s with CMIP5 results. This comparison shows good agreement, increasing the confidence of the climate models in representing the climate history.

In situ conversion process utilizing a closed loop heating system

DOEpatents

Sandberg, Chester Ledlie [Palo Alto, CA; Fowler, Thomas David [Houston, TX; Vinegar, Harold J [Bellaire, TX; Schoeber, Willen Jan Antoon Henri

2009-08-18

An in situ conversion system for producing hydrocarbons from a subsurface formation is described. The system includes a plurality of u-shaped wellbores in the formation. Piping is positioned in at least two of the u-shaped wellbores. A fluid circulation system is coupled to the piping. The fluid circulation system is configured to circulate hot heat transfer fluid through at least a portion of the piping to form at least one heated portion of the formation. An electrical power supply is configured to provide electrical current to at least a portion of the piping located below an overburden in the formation to resistively heat at least a portion of the piping. Heat transfers from the piping to the formation.

A hybrid geothermal energy conversion technology: Auxiliary heating of geothermally preheated water or CO2 - a potential solution for low-temperature resources

NASA Astrophysics Data System (ADS)

Saar, Martin; Garapati, Nagasree; Adams, Benjamin; Randolph, Jimmy; Kuehn, Thomas

2016-04-01

Safe, sustainable, and economic development of deep geothermal resources, particularly in less favourable regions, often requires employment of unconventional geothermal energy extraction and utilization methods. Often "unconventional geothermal methods" is synonymously and solely used as meaning enhanced geothermal systems, where the permeability of hot, dry rock with naturally low permeability at greater depths (4-6 km), is enhanced. Here we present an alternative unconventional geothermal energy utilization approach that uses low-temperature regions that are shallower, thereby drastically reducing drilling costs. While not a pure geothermal energy system, this hybrid approach may enable utilization of geothermal energy in many regions worldwide that can otherwise not be used for geothermal electricity generation, thereby increasing the global geothermal resource base. Moreover, in some realizations of this hybrid approach that generate carbon dioxide (CO2), the technology may be combined with carbon dioxide capture and storage (CCS) and CO2-based geothermal energy utilization, resulting in a high-efficiency (hybrid) geothermal power plant with a negative carbon footprint. Typically, low- to moderate-temperature geothermal resources are more effectively used for direct heat energy applications. However, due to high thermal losses during transport, direct use requires that the heat resource is located near the user. Alternatively, we show here that if such a low-temperature geothermal resource is combined with an additional or secondary energy resource, the power production is increased compared to the sum from two separate (geothermal and secondary fuel) power plants (DiPippo et al. 1978) and the thermal losses are minimized because the thermal energy is utilized where it is produced. Since Adams et al. (2015) found that using CO2 as a subsurface working fluid produces more net power than brine at low- to moderate-temperature geothermal resource conditions, we compare over a range of parameters the net power and efficiencies of hybrid geothermal power plants that use brine or CO2 as the subsurface working fluid, that are then heated further with a secondary energy source that is unspecified here. Parameters varied include the subsurface working fluid (brine vs. CO2), geothermal reservoir depth (2.5-4.5 km), and turbine inlet temperature (200-600°C) after auxiliary heating. The hybrid power plant is numerically modeled using an iterative coupling approach of TOUGH2-ECO2N/ECO2H (Pruess, 2004) for simulation of the subsurface reservoir and Engineering Equation Solver for well bore fluid flow and surface power plant performance. We find that hybrid power plants that are CO2-based (subsurface) systems produce more net power than the sum of the power produced by individual power plants at low turbine inlet temperatures and brine based systems produce more power at high turbine inlet temperatures. Specifically, our results indicate that geothermal hybrid plants that are CO2-based are more efficient than brine-based systems when the contribution of the geothermal resource energy is higher than 48%.

Escherichia coli Transport from Surface-Applied Manure to Subsurface Drains through Artificial Biopores

USDA-ARS?s Scientific Manuscript database

Transport of pathogenic bacteria in soils primarily occurs through soil mesopores and macropores (e.g., biopores and cracks). Field research has demonstrated that biopores and subsurface drains can be hydraulically connected. This research was conducted to investigate the importance of surface conne...

Evidence of weak land-atmosphere coupling under varying bare soil conditions: Are fully coupled Darcy/Navier-Stokes models necessary for simulating soil moisture dynamics?

NASA Astrophysics Data System (ADS)

Illangasekare, T. H.; Trautz, A. C.; Howington, S. E.; Cihan, A.

2017-12-01

It is a well-established fact that the land and atmosphere form a continuum in which the individual domains are coupled by heat and mass transfer processes such as bare-soil evaporation. Soil moisture dynamics can be simulated at the representative elementary volume (REV) scale using decoupled and fully coupled Darcy/Navier-Stokes models. Decoupled modeling is an asynchronous approach in which flow and transport in the soil and atmosphere is simulated independently; the two domains are coupled out of time-step via prescribed flux parameterizations. Fully coupled modeling in contrast, solves the governing equations for flow and transport in both domains simultaneously with the use of coupling interface boundary conditions. This latter approach, while being able to provide real-time two-dimensional feedbacks, is considerably more complex and computationally intensive. In this study, we investigate whether fully coupled models are necessary, or if the simpler decoupled models can sufficiently capture soil moisture dynamics under varying land preparations. A series of intermediate-scale physical and numerical experiments were conducted in which soil moisture distributions and evaporation estimates were monitored at high spatiotemporal resolutions for different heterogeneous packing and soil roughness scenarios. All experimentation was conducted at the newly developed Center for Experimental Study of Subsurface Environmental Processes (CESEP) wind tunnel-porous media user test-facility at the Colorado School of. Near-surface atmospheric measurements made during the experiments demonstrate that the land-atmosphere coupling was relatively weak and insensitive to the applied edaphic and surface conditions. Simulations with a decoupled multiphase heat and mass transfer model similarly show little sensitivity to local variations in atmospheric forcing; a single, simple flux parameterization can sufficiently capture the soil moisture dynamics (evaporation and redistribution) as long as the subsurface conditions (i.e., heterogeneity) are properly described. These findings suggest that significant improvements to simulations results should not be expected if fully coupled modeling were adopted in scenarios of weak land-atmosphere coupling in the context of bare soil evaporation.

Heat as a groundwater tracer in shallow and deep heterogeneous media: Analytical solution, spreadsheet tool, and field applications

USGS Publications Warehouse

Kurylyk, Barret L.; Irvine, Dylan J.; Carey, Sean K.; Briggs, Martin A.; Werkema, Dale D.; Bonham, Mariah

2017-01-01

Groundwater flow advects heat, and thus, the deviation of subsurface temperatures from an expected conduction‐dominated regime can be analysed to estimate vertical water fluxes. A number of analytical approaches have been proposed for using heat as a groundwater tracer, and these have typically assumed a homogeneous medium. However, heterogeneous thermal properties are ubiquitous in subsurface environments, both at the scale of geologic strata and at finer scales in streambeds. Herein, we apply the analytical solution of Shan and Bodvarsson (2004), developed for estimating vertical water fluxes in layered systems, in 2 new environments distinct from previous vadose zone applications. The utility of the solution for studying groundwater‐surface water exchange is demonstrated using temperature data collected from an upwelling streambed with sediment layers, and a simple sensitivity analysis using these data indicates the solution is relatively robust. Also, a deeper temperature profile recorded in a borehole in South Australia is analysed to estimate deeper water fluxes. The analytical solution is able to match observed thermal gradients, including the change in slope at sediment interfaces. Results indicate that not accounting for layering can yield errors in the magnitude and even direction of the inferred Darcy fluxes. A simple automated spreadsheet tool (Flux‐LM) is presented to allow users to input temperature and layer data and solve the inverse problem to estimate groundwater flux rates from shallow (e.g., <1 m) or deep (e.g., up to 100 m) profiles. The solution is not transient, and thus, it should be cautiously applied where diel signals propagate or in deeper zones where multi‐decadal surface signals have disturbed subsurface thermal regimes.

Subsurface wrinkle removal by laser treatment in combination with dynamic cooling

NASA Astrophysics Data System (ADS)

Paithankar, Dilip Y.; Hsia, James C.; Ross, E. V.

2000-05-01

Compared to traditional CO2 or Er:YAG laser resurfacing, sub-surface thermal injury to stimulate skin remodeling for the removal of wrinkles is attractive due to the lower morbidity associated with epidermal preservation. We have developed a technique that thermally damages dermal collagen while preserving the epidermis by a combination of infra-red laser irradiation and dynamic cooling of skin. Wound healing response to the thermal denaturation of collagen may trigger synthesis of fresh collagen and result in restoration of a more youthful appearance. The laser wavelength is chosen so as to thermally injure dermis in a narrow band at depths of 150 to 500 microns from the surface of the skin. The epidermis is preserved by a Candela dynamic cooling device (DCDTM) cryogen spray. Three-dimensional Monte Carlo calculations have been done to calculate the light distribution within tissue while taking into account light absorption and scattering. This light distribution has been used to calculate heat generation within tissue. Heat transfer calculations have been done while taking into consideration the cryogen cooling. The resulting temperature profiles have been used to suggest heating and cooling parameters. Freshly excised ex vivo pig skin was irradiated with laser and DCD at these heating and cooling parameters. Histological evaluation of the biopsies has shown that it is possible to spare the epidermis while thermally denaturing the dermal collagen. The modeling and histology results are discussed.

Multifluid geo-energy systems: Using geologic CO 2 storage for geothermal energy production and grid-scale energy storage in sedimentary basins

DOE PAGES

Buscheck, Thomas A.; Bielicki, Jeffrey M.; Edmunds, Thomas A.; ...

2016-05-05

We present an approach that uses the huge fluid and thermal storage capacity of the subsurface, together with geologic carbon dioxide (CO 2) storage, to harvest, store, and dispatch energy from subsurface (geothermal) and surface (solar, nuclear, fossil) thermal resources, as well as excess energy on electric grids. Captured CO 2 is injected into saline aquifers to store pressure, generate artesian flow of brine, and provide a supplemental working fluid for efficient heat extraction and power conversion. Concentric rings of injection and production wells create a hydraulic mound to store pressure, CO 2, and thermal energy. This energy storage canmore » take excess power from the grid and excess/waste thermal energy, and dispatch that energy when it is demanded and thus enable higher penetration of variable renewable energy technologies (e.g., wind, solar). CO 2 stored in the subsurface functions as a cushion gas to provide enormous pressure-storage capacity and displace large quantities of brine, some of which can be treated for a variety of beneficial uses. Geothermal power and energy-storage applications may generate enough revenues to compensate for CO 2 capture costs. While our approach can use nitrogen (N 2), in addition to CO 2, as a supplemental fluid, and store thermal energy, this study focuses using CO 2 for geothermal energy production and grid-scale energy storage. We conduct a techno-economic assessment to determine the levelized cost of electricity of using this approach to generate geothermal power. We present a reservoir pressure-management strategy that diverts a small portion of the produced brine for beneficial consumptive use to reduce the pumping cost of fluid recirculation, while reducing the risk of seismicity, caprock fracture, and CO 2 leakage.« less

Drip irrigation research update at NPRL

USDA-ARS?s Scientific Manuscript database

Drip irrigation research has been conducted since 1998 at NPRL. Systems include deep subsurface drip irrigation (SSDI), surface drip irrigation (SDI), and shallow subsurface drip irrigation (S3DI). Results have shown that SDI and S3DI are more economical to install than SSDI. SDI systems have more r...

COMPONENTS OF SURFACE AND SUBSURFACE CONNECTIVITY IN A LARGE OREGON (USA) RIVER--WHAT CAN BE RESTORED?

EPA Science Inventory

We conducted research on the Willamette River in western Oregon (USA) to determine the ecological functions of off-channel habitats (OCH). OCHs have declined in our 70 km study reach of the active floodplain since European settlement. Surface and subsurface connectivity between...

Yield response and economics of shallow subsurface drip irrigation systems

USDA-ARS?s Scientific Manuscript database

Field tests were conducted using shallow subsurface drip irrigation (S3DI) on cotton (Gossypium hirsutum, L.), corn (Zea mays, L.), and peanut (Arachis hypogeae, L.) in rotation to investigate yield potential and economic sustainability of this irrigation system technique over a six year period. Dri...

Estimation of deepwater temperature and hydrogeochemistry of springs in the Takab geothermal field, West Azerbaijan, Iran.

PubMed

Sharifi, Reza; Moore, Farid; Mohammadi, Zargham; Keshavarzi, Behnam

2016-01-01

Chemical analyses of water samples from 19 hot and cold springs are used to characterize Takab geothermal field, west of Iran. The springs are divided into two main groups based on temperature, host rock, total dissolved solids (TDS), and major and minor elements. TDS, electrical conductivity (EC), Cl(-), and SO4 (2-) concentrations of hot springs are all higher than in cold springs. Higher TDS in hot springs probably reflect longer circulation and residence time. The high Si, B, and Sr contents in thermal waters are probably the result of extended water-rock interaction and reflect flow paths and residence time. Binary, ternary, and Giggenbach diagrams were used to understand the deeper mixing conditions and locations of springs in the model system. It is believed that the springs are heated either by mixing of deep geothermal fluid with cold groundwater or low conductive heat flow. Mixing ratios are evaluated using Cl, Na, and B concentrations and a mass balance approach. Calculated quartz and chalcedony geothermometer give lower reservoir temperatures than cation geothermometers. The silica-enthalpy mixing model predicts a subsurface reservoir temperature between 62 and 90 °C. The δ(18)O and δD (δ(2)H) are used to trace and determine the origin and movement of water. Both hot and cold waters plot close to the local meteoric line, indicating local meteoric origin.

Active Heat Injection to Investigate Seepage Conditions Along the Interface Between a Concrete Diversion Sluiceway and Earthen Embankment Dam

NASA Astrophysics Data System (ADS)

Ringeri, A.; Butler, K. E.; MacQuarrie, K. T. B.

2016-12-01

The interface between embankment dams and adjoining hydraulic structures are regions which can give rise to seepage defects. A field experiment was conducted at the Mactaquac Generating Station in New Brunswick, Canada using active thermometry to investigate seepage conditions along the interface of a diversion sluiceway and earth embankment. The method involved monitoring the time evolution of temperature following the injection of a controlled heat pulse from a subsurface heat cable acting as a line source. Transient anomalies in the induced temperature field can result from the aberration of thermal properties and flow conditions which accompany defects. An industrial heat trace cable and distributed temperature sensing (DTS) fibre optic cable were installed in two parallel, 42 m deep, sub-vertical boreholes separated by 3 m and offset 0.5 m from the core-concrete interface. The heat and DTS cables were installed in the upstream and downstream boreholes respectively. Heat was injected as a box car function at a constant rate of 78.72 W/m for 51 d while the DTS cable, with a 20 cm sampling resolution, was averaged over 10 min at 30 min intervals for 300 d. The DTS cable successfully detected temperature changes induced by the upstream heat pulse. A coherent temperature response occurred along a 13 m section of deep fibre, where mean peak temperatures rose 1.59 ± 0.03 °C above ambient temperatures with an average time lag of 8.2 d following the end of the heating cycle. Two temperature anomalies above this region coincided with the position of the water table and the location of a previously detected fibre break. The method appears to be particularly useful in seepage surveillance of the deeper regions of the interface. Further analysis is required to remove the influence of seasonal temperatures on the heat pulse response at shallow depths.

Shallow Horizontal GCHP Effectiveness in Arid Climate Soils

NASA Astrophysics Data System (ADS)

North, Timothy James

Ground coupled heat pumps (GCHPs) have been used successfully in many environments to improve the heating and cooling efficiency of both small and large scale buildings. In arid climate regions, such as the Phoenix, Arizona metropolitan area, where the air condi-tioning load is dominated by cooling in the summer, GCHPs are difficult to install and operate. This is because the nature of soils in arid climate regions, in that they are both dry and hot, renders them particularly ineffective at dissipating heat. The first part of this thesis addresses applying the SVHeat finite element modeling soft-ware to create a model of a GCHP system. Using real-world data from a prototype solar-water heating system coupled with a ground-source heat exchanger installed in Menlo Park, California, a relatively accurate model was created to represent a novel GCHP panel system installed in a shallow vertical trench. A sensitivity analysis was performed to evaluate the accuracy of the calibrated model. The second part of the thesis involved adapting the calibrated model to represent an ap-proximation of soil conditions in arid climate regions, using a range of thermal properties for dry soils. The effectiveness of the GCHP in the arid climate region model was then evaluated by comparing the thermal flux from the panel into the subsurface profile to that of the prototype GCHP. It was shown that soils in arid climate regions are particularly inefficient at heat dissipation, but that it is highly dependent on the thermal conductivity inputted into the model. This demonstrates the importance of proper site characterization in arid climate regions. Finally, several soil improvement methods were researched to evaluate their potential for use in improving the effectiveness of shallow horizontal GCHP systems in arid climate regions.

The stability against freezing of an internal liquid-water ocean in Callisto.

PubMed

Ruiz, J

2001-07-26

The discovery of the induced magnetic field of Callisto-one of Jupiter's moons-has been interpreted as evidence for a subsurface ocean, even though the presence of such an ocean is difficult to understand in the context of existing theoretical models. Tidal heating should not be significant for Callisto, and, in the absence of such heating, it is difficult to see how this internal ocean could have survived until today without freezing. Previous work indicated that an outer ice layer on the ocean would be unstable against solid-state convection, which once begun would lead to total freezing of liquid water in about 108 years. Here I show that when a methodology for more physically reasonable water ice viscosities (that is, stress-dependent non-newtonian viscosities, rather than the stress-independent newtonian viscosities considered previously) is adopted, the outer ice shell becomes stable against convection. This implies that a subsurface ocean could have survived up to the present, without the need for invoking antifreeze substances or other special conditions.

Corn stover harvest increases herbicide movement to subsurface drains: RZWQM simulations

USGS Publications Warehouse

Shipitalo, Martin J.; Malone, Robert W.; Ma, Liwang; Nolan, Bernard T.; Kanwar, Rameshwar S.; Shaner, Dale L.; Pederson, Carl H.

2016-01-01

BACKGROUND Crop residue removal for bioenergy production can alter soil hydrologic properties and the movement of agrochemicals to subsurface drains. The Root Zone Water Quality Model (RZWQM), previously calibrated using measured flow and atrazine concentrations in drainage from a 0.4 ha chisel-tilled plot, was used to investigate effects of 50 and 100% corn (Zea mays L.) stover harvest and the accompanying reductions in soil crust hydraulic conductivity and total macroporosity on transport of atrazine, metolachlor, and metolachlor oxanilic acid (OXA). RESULTS The model accurately simulated field-measured metolachlor transport in drainage. A 3-yr simulation indicated that 50% residue removal decreased subsurface drainage by 31% and increased atrazine and metolachlor transport in drainage 4 to 5-fold when surface crust conductivity and macroporosity were reduced by 25%. Based on its measured sorption coefficient, ~ 2-fold reductions in OXA losses were simulated with residue removal. CONCLUSION RZWQM indicated that if corn stover harvest reduces crust conductivity and soil macroporosity, losses of atrazine and metolachlor in subsurface drainage will increase due to reduced sorption related to more water moving through fewer macropores. Losses of the metolachlor degradation product OXA will decrease due to the more rapid movement of the parent compound into the soil.

Sensitivity of transpiration to subsurface properties: Exploration with a 1-D model

NASA Astrophysics Data System (ADS)

Vrettas, Michail D.; Fung, Inez Y.

2017-06-01

The amount of moisture transpired by vegetation is critically tied to the moisture supply accessible to the root zone. In a Mediterranean climate, integrated evapotranspiration (ET) is typically greater in the dry summer when there is an uninterrupted period of high insolation. We present a 1-D model to explore the subsurface factors that may sustain ET through the dry season. The model includes a stochastic parameterization of hydraulic conductivity, root water uptake efficiency, and hydraulic redistribution by plant roots. Model experiments vary the precipitation, the magnitude and seasonality of ET demand, as well as rooting profiles and rooting depths of the vegetation. The results show that the amount of subsurface moisture remaining at the end of the wet winter is determined by the competition among abundant precipitation input, fast infiltration, and winter ET demand. The weathered bedrock retains ˜30% of the winter rain and provides a substantial moisture reservoir that may sustain ET of deep-rooted (>8 m) trees through the dry season. A small negative feedback exists in the root zone, where the depletion of moisture by ET decreases hydraulic conductivity and enhances the retention of moisture. Hence, hydraulic redistribution by plant roots is impactful in a dry season, or with a less conductive subsurface. Suggestions for implementing the model in the CESM are discussed.

Ecohydrologic Changes due to Tree Expansion into Tundra in the Polar Urals, Russia

NASA Astrophysics Data System (ADS)

Ivanov, V. Y.; Wang, J.; El Sharif, H. A.; Liu, D.; Sheshukov, A. Y.; Mazepa, V.; Shiyatov, S.; Sokolov, A.

2017-12-01

The Arctic has been warming at an accelerating rate over the last several decades and the changing climate has caused the invasion of trees and shrubs into tundra across the polar regions of Alaska, Canada, and Russia. These vegetation changes may have the potential to impact regional hydrology and climate. This study aims to develop mechanistic and quantitative understanding of implications of forest encroachment into tundra. Specifically, for several areas with well-documented larch and spruce expansion in the Polar Urals and southern Yamal Peninsula of Russia over 1960-2010s, we hypothesize that the encroachment process alters the seasonality of energy budget characterized by enhanced total evapotranspiration and concomitant subsurface warming. We are collecting a comprehensive set of field observational data on micrometeorology, snow conditions, radiative fluxes, tree sap flows, soil temperature, moisture, and heat fluxes, and active layer thickness. A novel model of maximum entropy production (MEP) is used to derive the surface energy budgets as the partition of radiative fluxes into turbulent and conductive heat fluxes across the ecotone interface. We are presenting preliminary findings that illustrate the identified differences of seasonal snow and heat budget regimes for two contrasting sites: one of which has experienced a recent tree encroachment, while for the other this process has not yet occurred. Observed and modeled heat fluxes are used to inform a comprehensive physical model to study the impact of vegetation encroachment process on the permafrost dynamics.

Performance, Cost, and Financial Parameters of Geothermal District Heating Systems for Market Penetration Modeling under Various Scenarios

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

Beckers, Koenraad J; Young, Katherine R

Geothermal district heating (GDH) systems have limited penetration in the U.S., with an estimated installed capacity of only 100 MWth for a total of 21 sites. We see higher deployment in other regions, for example, in Europe with an installed capacity of more than 4,700 MWth for 257 GDH sites. The U.S. Department of Energy Geothermal Vision (GeoVision) Study is currently looking at the potential to increase the deployment in the U.S. and to understand the impact of this increased deployment. This paper reviews 31 performance, cost, and financial parameters as input for numerical simulations describing GDH system deployment inmore » support of the GeoVision effort. The focus is on GDH systems using hydrothermal and Enhanced Geothermal System resources in the U.S.; ground-source heat pumps and heat-to-electricity conversion technology were excluded. Parameters investigated include 1) capital and operation and maintenance costs for both subsurface and surface equipment; 2) performance factors such as resource recovery factors, well flow rates, and system efficiencies; and 3) financial parameters such as inflation, interest, and tax rates. Current values as well as potential future improved values under various scenarios are presented. Sources of data considered include academic and popular literature, software tools such as GETEM and GEOPHIRES, industry interviews, and analysis conducted by other task forces for the GeoVision Study, e.g., on the drilling costs and reservoir performance.« less

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

NASA Astrophysics Data System (ADS)

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

2017-09-01

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

New temperature model of the Netherlands from new data and novel modelling methodology

NASA Astrophysics Data System (ADS)

Bonté, Damien; Struijk, Maartje; Békési, Eszter; Cloetingh, Sierd; van Wees, Jan-Diederik

2017-04-01

Deep geothermal energy has grown in interest in Western Europe in the last decades, for direct use but also, as the knowledge of the subsurface improves, for electricity generation. In the Netherlands, where the sector took off with the first system in 2005, geothermal energy is seen has a key player for a sustainable future. The knowledge of the temperature subsurface, together with the available flow from the reservoir, is an important factor that can determine the success of a geothermal energy project. To support the development of deep geothermal energy system in the Netherlands, we have made a first assessment of the subsurface temperature based on thermal data but also on geological elements (Bonté et al, 2012). An outcome of this work was ThermoGIS that uses the temperature model. This work is a revision of the model that is used in ThermoGIS. The improvement from the first model are multiple, we have been improving not only the dataset used for the calibration and structural model, but also the methodology trough an improved software (called b3t). The temperature dataset has been updated by integrating temperature on the newly accessible wells. The sedimentary description in the basin has been improved by using an updated and refined structural model and an improved lithological definition. A major improvement in from the methodology used to perform the modelling, with b3t the calibration is made not only using the lithospheric parameters but also using the thermal conductivity of the sediments. The result is a much more accurate definition of the parameters for the model and a perfected handling of the calibration process. The result obtain is a precise and improved temperature model of the Netherlands. The thermal conductivity variation in the sediments associated with geometry of the layers is an important factor of temperature variations and the influence of the Zechtein salt in the north of the country is important. In addition, the radiogenic heat production in the crust shows a significant impact. From the temperature values, also identify in the lower part of the basin, deep convective systems that could be major geothermal energy target in the future.

Efficient infiltration of water in the subsurface by using point-wells: A field study

NASA Astrophysics Data System (ADS)

Lopik, J. V.; Schotting, R.; Raoof, A.

2017-12-01

The ability to infiltrate large volumes of water in the subsurface would have great value for battling flooding in urban regions. Moreover, efficient water infiltration is key to optimize underground aquifer storage and recovery (ASR), aquifer thermal energy storage (ATES), as well as construction dewatering systems. Usually, variable infiltration rates of large water quantities could have a huge hydrogeological impact in the upper part of (phreatic) aquifer systems. In urban regions, minimizing excessive groundwater table fluctuations are necessary. A newly developed method, Fast, High Volume Infiltration (FHVI), by Dutch dewatering companies can be used to enable fast injection into the shallow subsurface. Conventional infiltration methods are using injection wells that screen large parts of the aquifer depth, whereas FHVI uses a specific infiltration point (1-m well screen) in the aquifer. These infiltration points are generally thin, high permeable layers in the aquifer of approximately 0.5-2 meter thick, and are embedded by less permeable layers. Currently, much higher infiltration pressures in shallow aquifers can be achieved with FHVI (up to 1 bar) compared to conventional infiltration methods ( 0.2 bar). Despite the high infiltration pressures and high discharge rate near the FHVI-filter, the stresses on shallow groundwater levels are significantly reduced with FHVI. In order to investigate the mechanisms that enable FHVI, a field experiment is conducted in a sandy aquifer to obtain insight in the 3-D hydraulic pressure distribution and flow patterns around a FHVI-filter during infiltration. A detailed characterization of the soil profile is obtained by using soil samples and cone pressure tests with a specific hydraulic profiling tool to track the vertical variation in aquifer permeability. A tracer test with bromide and heat is conducted to investigate preferential flow paths. The experimental data show that tracking small heterogeneities in aquifers and analysing the permeability difference ratio between the aimed infiltration layer and the surrounding layers in the aquifer are key to optimize the configuration of the FHVI-well. The results show that the use of point wells in thin, high permeable layers could drastically improve the efficiency of the infiltration system.

Tremors behind the power outlet - where earthquakes appear on our monthly bill

NASA Astrophysics Data System (ADS)

Baisch, Stefan

2013-04-01

The world's appetite for energy has significantly increased over the last decades, not least due to the rapid growth of Asian economies. In parallel, the Fukushima shock raised widespread concerns against nuclear power generation and an increasing desire for clean energy technologies. To solve the conflict of higher demands, limited resources and a growing level of green consciousness, both up-scaling of conventional and development of renewable energy technologies are required. This is where the phenomenon of man-made earthquakes appears on the radar screen. Several of our energy production technologies have the potential to cause small, moderate, or sometimes even larger magnitude earthquakes. There is a general awareness that coal mining activities can produce moderate sized earthquakes. Similarly, long-term production from hydrocarbon reservoirs can lead to subsurface deformations accompanied by even larger magnitude earthquakes. Even the "renewables" are not necessarily earthquake-free. Several of the largest man-made earthquakes have been caused by water impoundment for hydropower plants. On a much smaller scale, micro earthquakes can occur in enhanced geothermal systems (EGS). Although still in its infancy, the EGS technology has an enormous potential to supply base load electricity, and its technical feasibility for a large scale application is currently being investigated in about a dozen pilot projects. The principal concept of heat extraction by circulating water through a subsurface reservoir is fairly simple, the technical implementation of EGS, however, exhibits several challenges not all of which are yet being solved. As the hydraulic conductivity at depth is usually extremely low at EGS sites, a technical stimulation of hydraulic pathways is required for creating an artificial heat exchanger. By injecting fluid under high pressure into the subsurface, tectonic stress on existing fractures can be released and the associated shearing of the fractures (micro earthquakes) increases the hydraulic conductivity. Magnitudes of the induced micro earthquakes are typically below the human detection threshold, but a few exceptionally strong events in the order of ML=3.5 have occurred in EGS reservoirs. In one case, slight material damage was caused, which eventually led to a project stop. Although these induced micro earthquakes are usually generated under well-controlled conditions, the possibility of rare occurrences of felt events in EGS reservoirs remains part of the technology. The same applies for the up-scaling of hydrocarbon production. Tapping unconventional resources requires similar stimulation technologies as used for EGS. Every power production technology has got its prize - we have to decide what currency we are willing to pay and to what extent we are ready to accept the small tremors behind our power outlet.

Alternate energy source usage methods for in situ heat treatment processes

DOEpatents

Stone, Jr., Francis Marion; Goodwin, Charles R; Richard, Jr., James E

2014-10-14

Systems, methods, and heaters for treating a subsurface formation are described herein. At least one method for providing power to one or more subsurface heaters is described herein. The method may include monitoring one or more operating parameters of the heaters, the intermittent power source, and a transformer coupled to the intermittent power source that transforms power from the intermittent power source to power with appropriate operating parameters for the heaters; and controlling the power output of the transformer so that a constant voltage is provided to the heaters regardless of the load of the heaters and the power output provided by the intermittent power source.

A 1-D Cryothermal Model of Ceres’ Megaregolith: Predictions for Surface Vapor Flux, Subsurface Temperatures and Pore Ice Distribution

NASA Astrophysics Data System (ADS)

Reynolds, Dylan; Wood, Stephen E.; Bapst, Jonathan; Mehlhaff, Joshua; Griffiths, Stephen G.

2014-11-01

We have applied a self-consistent 1-D model for heat diffusion, vapor diffusion, and ice condensation/sublimation, and surface energy balance to investigate our hypothesis for the source of the recently observed water vapor around Ceres [1]. As described in a companion presentation [2], we find that the estimated global flux of 6 kg/s can be produced by steady-state sublimation of subsurface ice driven by the “geothermal” temperature gradient for a heat flux of 1 mW/m2 - the value estimated for a chondritic abundance of heat-producing elements [3,4]. We will present a detailed description of our Ceres cryothermal diffusion model and comparisons with previous models. One key difference is the use of a new physics-based analytic model (‘MaxRTCM’) for calculating the thermal conductivity (Kth) of planetary regolith [5] that has been validated by comparisons to a wide range of laboratory data [6]. MaxRTCM predicts much lower Kth values in the upper regolith than those in previous work [3]. It also accounts for a process first modeled in a study of unstable equatorial ground ice on Mars [7,8], where vapor diffusing up from a receding ice table toward the surface can recondense at shallower depths - eventually forming a steady-state profile of pore ice volume fraction that increases with depth and maintains a constant flux of vapor at all depths [7]. Using MaxRTCM we calculate the corresponding Kth(z) profiles and will present predictions and implications of the resulting temperature profile in the upper few kilometers of Ceres’ megaregolith.References: [1] Küppers et al. (2014), Nature, 505(7484), 525-527. [2] Wood et al., 2014, this meeting. [3] Fanale & Salvail (1989) Icarus 82, 97-110. [4] McCord and Sotin (2005) JGR 110, E05009. [5] Wood (2013) LPSC Abs. 44, 3077. [6] Wood (2014), Icarus, in revision. [7] Mellon et al. (1997), JGR, 102, 19357-69. [8] Clifford (1993), JGR, 98, 10973-11016.

G.O.THERM.3D - Providing a 3D Atlas of Temperature in Ireland's Subsurface

NASA Astrophysics Data System (ADS)

Farrell, Thomas; Fullea, Javier

2017-04-01

We introduce the recently initiated project G.O.THERM.3D, which aims to develop a robust and unique model of temperature within Ireland's crust and to produce a 3D temperature atlas of the country. The temperature model will be made publicly available on an interactive online platform, and the project findings will be reported to appropriate state energy and geoscience bodies. The project objective is that an interactive, publicly available 3D temperature model will increase public awareness of geothermal energy. The aim is also that the project findings will focus and encourage geothermal resource exploration and will assist in the development of public policy on geothermal energy exploration, mapping, planning and exploitation. Previous maps of temperature at depth in Ireland's subsurface are heavily reliant on temperature observations in geographically-clustered, shallow boreholes. These maps also make insufficient allowance for near-surface perturbation effects (such as the palaeoclimatic effect), do not allow for the 3D variation of petrophysical parameters and do not consider the deep, lithospheric thermal structure. To develop a 3D temperature model of Ireland's crust, G.O.THERM.3D proposes to model both the compositional and thermal structure of the Irish crust using the LitMod3D geophysical-petrological modelling tool. LitMod3D uses an integrated approach that simultaneously accounts for multiple geophysical (heat-flow, gravity, topography, magnetotelluric, seismic) and petrological (thermal conductivity, heat-production, xenolith composition) datasets, where the main rock properties (density, electrical resistivity, seismic velocity) are thermodynamically computed based on the temperature and bulk rock composition. LitMod3D has been applied to study the lithosphere-asthenosphere boundary (LAB) beneath Ireland (at a depth of 100 km) and is typically used to investigate lithospheric-scale structures. In the previous studies focussing on the LAB beneath Ireland, LitMod3D models the crust as two fixed homogenous layers with laterally constant physical properties (upper-middle crust and lower crust). G.O.THERM.3D proposes to adapt the LitMod3D tool to model the heterogeneous nature of the crust, e.g. the variable distribution of heat production and the variation of thermal conductivity with lithology and temperature, with an appropriate lateral and vertical resolution. The thermal modelling process will also employ palaeoclimate-corrected heat-flow and other available complementary data sets (e.g. seismic, magnetic, radiometric and electromagnetic). Existing and emerging lithospheric-regional temperature models will be used to apply thermal boundary conditions to the crustal model of G.O.THERM.3D. The resulting crustal temperature model of G.O.THERM.3D may in turn be used to provide boundary conditions on more focussed modelling on a shallower scale (e.g. within a sedimentary basin to depths of 5 km). In this way, a nested approach can be adopted to model compositional and thermal structures on various scales and resolutions within the crust (subject to the availability of appropriate data), while maintaining consistency with the wider setting. G.O.THERM.3D will also make additional thermal conductivity measurements, the primary motivation for which being the critical importance of thermal conductivity data in constraining temperature modelling.

Geothermal studies at Kirtland Air Force Base, Albuquerque, New Mexico

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

Riddle, L.; Grant, B.

Due to an effort by government installations to discontinue use of natural gas, alternative energy sources are being investigated at Kirtland Air Force Base, Albuquerque, New Mexico. New Mexico has geologic characteristics favorable for geothermal energy utilization. Local heat flow and geochemical studies indicate a normal subsurface temperature regime. The alluvial deposits, however, extend to great depths where hot fluids, heated by the normal geothermal gradient, could be encountered. Two potential models for tapping geothermal energy are presented: the basin model and the fault model.

WESTERN RESEARCH INSTITUTE CONTAINED RECOVERY OF OILY WASTES (CROW) PROCESS - ITER

EPA Science Inventory

This report summarizes the findings of an evaluation of the Contained Recovery of Oily Wastes (CROW) technology developed by the Western Research Institute. The process involves the injection of heated water into the subsurface to mobilize oily wastes, which are removed from the ...

Yield and economics of shallow subsurface drip irrigation (S3DI) and furrow diking

USDA-ARS?s Scientific Manuscript database

A shallow subsurface drip irrigation (S3DI) was installed yearly in conjunction with furrow diking to document yield and economic benefit of these techniques on peanut (Arachis hypogaea L.), cotton (Gossypium hirsutum L.), and corn (Zea mays L.). This research was conducted for three years from 2005...

CSAMT method for determining depth and shape of a sub-surface conductive object

DOEpatents

Lee, David O.; Montoya, Paul C.; Wayland, Jr., J. Robert

1986-01-01

The depth to and size of an underground object may be determined by sweeping a CSAMT signal and locating a peak response when the receiver spans the edge of the object. The depth of the object is one quarter wavelength in the subsurface media of the frequency of the peak.

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

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

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

1999-06-01

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

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

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

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

2002-11-20

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

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

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

Lee, Ki Ha; Becker, Alex

2000-06-01

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

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

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

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

2001-06-10

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

Trans-dimensional Bayesian inversion of airborne electromagnetic data for 2D conductivity profiles

NASA Astrophysics Data System (ADS)

Hawkins, Rhys; Brodie, Ross C.; Sambridge, Malcolm

2018-02-01

This paper presents the application of a novel trans-dimensional sampling approach to a time domain airborne electromagnetic (AEM) inverse problem to solve for plausible conductivities of the subsurface. Geophysical inverse field problems, such as time domain AEM, are well known to have a large degree of non-uniqueness. Common least-squares optimisation approaches fail to take this into account and provide a single solution with linearised estimates of uncertainty that can result in overly optimistic appraisal of the conductivity of the subsurface. In this new non-linear approach, the spatial complexity of a 2D profile is controlled directly by the data. By examining an ensemble of proposed conductivity profiles it accommodates non-uniqueness and provides more robust estimates of uncertainties.

Parameterization and Modeling of Coupled Heat and Mass Transport in the Vadose Zone

NASA Astrophysics Data System (ADS)

Mohanty, B.; Yang, Z.

2016-12-01

The coupled heat and mass transport in the vadose zone is essentially a multiphysics issue. Addressing this issue appropriately has remarkable impacts on soil physical, chemical and biological processes. To data, most coupled heat and water transport modeling has focused on the interactions between liquid water, water vapor and heat transport in homogeneous and layered soils. Comparatively little work has been done on structured soils where preferential infiltration and evaporation flow occurs. Moreover, the traditional coupled heat and water model usually neglects the nonwetting phase air flow, which was found to be significant in the state-of-the-art modeling framework for coupled heat and water transport investigation. However, the parameterizations for the nonwetting phase air permeability largely remain elusive so far. In order to address the above mentioned limitations, this study aims to develop and validate a predictive multiphysics modeling framework for coupled soil heat and water transport in the heterogeneous shallow subsurface. To this end, the following research work is specifically conducted: (a) propose an improved parameterization to better predict the nonwetting phase relative permeability; (b) determine the dynamics, characteristics and processes of simultaneous soil moisture and heat movement in homogeneous and layered soils; and (c) develop a nonisothermal dual permeability model for heterogeneous structured soils. The results of our studies showed that: (a) the proposed modified nonwetting phase relative permeability models are much more accurate, which can be adopted for better parameterization in the subsequent nonisothermal two phase flow models; (b) the isothermal liquid film flow, nonwetting phase gas flow and liquid-vapor phase change non-equilibrium effects are significant in the arid and semiarid environments (Riverside, California and Audubon, Arizona); and (c) the developed nonisothermal dual permeability model is capable of characterizing the preferential evaporation path in the heterogeneous structured soils due to the fact that the capillary forces divert the pore water from coarse-textured soils (high temperature region) toward the fine-textured soils (low temperature region).

Bottom-simulating reflector variability at the Costa Rica subduction zone and corresponding heat flow model

NASA Astrophysics Data System (ADS)

Cavanaugh, S.; Bangs, N. L.; Hornbach, M. J.; McIntosh, K. D.

2011-12-01

We use 3D seismic reflection data acquired in April - May 2011 by the R/V Marcus G. Langseth to extract heat flow information using the bottom-simulating reflector across the Costa Rica convergent margin. These data are part of the CRISP Project, which will image the Middle America subduction zone in 3D. The survey was conducted in an area approximately 55 x 11 km, to the northwest of the Osa Peninsula, Costa Rica. For the analysis presented here, 3D seismic data were processed with Paradigm Focus software through post-stack time migration. The bottom-simulating reflector (BSR)-a reverse polarity reflection indicating the base of the gas hydrate phase boundary-is imaged very clearly in two regions within the slope-cover sediments in the accretionary prism. In deep water environments, the BSR acts as a temperature gauge revealing subsurface temperatures across the margin. We predict BSR depth using a true 3D diffusive heat flow model combined with IODP drilling data and compare results with actual BSR depth observations to determine anomalies in heat flow. Uniform heat flow in the region should result in a deepening BSR downslope toward the trench, however our initial results indicate the BSR shoals near the trench to its shallowest level below sea floor of approximately 96 m below the sea floor, suggesting elevated heat flow towards the toe. Landward, the BSR deepens to about 333 m below the sea floor indicating lower heat flow. Both BSR segments display a trend of deepening landward from the trench, however the depth below the sea floor is greater overall for the landward segment than the segment near the toe. We suggest two regimes with differing heat flow exist across the margin that likely represent two separate fluid flow regimes - one from recently accreted sediments near the prism toe and the other through the older materials making up the prism.

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

NASA Astrophysics Data System (ADS)

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

2017-12-01

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

In-Situ Air Sparaing: Engineering and Design

DTIC Science & Technology

2008-01-31

Construction Materials. Although PVC casing is commonly used, flexible or rigid polyethylene pipe may be more efficient for certain excavation methods, such as...depth, etc.) Piping insulation/ heat tape installed Piping flushed/cleaned/pressure tested Subsurface as-built equipment...4-4 Figure 4-2 Pilot-Scale Piping and Instrumentation Diagram

Thermal history of the Acoculco geothermal system, eastern Mexico: Insights from numerical modeling and radiocarbon dating

NASA Astrophysics Data System (ADS)

Canet, Carles; Trillaud, Frederic; Prol-Ledesma, Rosa María; González-Hernández, Galia; Peláez, Berenice; Hernández-Cruz, Berenice; Sánchez-Córdova, María M.

2015-10-01

Acoculco is a geothermal prospective area hosted by a volcanic caldera complex in the eastern Trans-Mexican Volcanic Belt. Surface manifestations are scarce and consist of gas discharges (CO2-rich) and acid-sulfate springs of low temperature, whereas hydrothermal explosive activity is profusely manifested by meter-scale craters and mounds of hydrothermal debris and breccias. Silicic alteration extends for several square kilometers around the zone with gas manifestations and explosive features, affecting surficial volcanic rocks, primarily tuffs and breccias. In the subsurface, an argillic alteration zone (ammonium illite) extends down to a depth of ∼ 600 m, and underneath it a propylitic zone (epidote-calcite-chlorite) occurs down to ∼ 1000 m. Thermal logs from an exploratory borehole (EAC-1, drilled in 1995 down to 1810 m) showed a conductive heat transfer regime under high geothermal gradient (∼ 140 °C/1000 m). In contrast, the thermal profile established from temperatures of homogenization of fluid inclusions-measured on core samples from the same drill hole-suggests that convection occurred in the past through the upper ~ 1400 m of the geothermal system. A drop in permeability due to the precipitation of alteration minerals would have triggered the cessation of the convective heat transfer regime to give place to a conductive one. With the purpose of determining when the transition of heat transfer regime occurred, we developed a 1D model that simulates the time-depth distribution of temperature. According to our numerical simulations, this transition happened ca. 7000 years ago; this date is very recent compared to the lifespan of the geothermal system. In addition, radiocarbon chronology indicates that the hydrothermal explosive activity postdates the end of the convective heat transfer regime, having dated at least three explosive events, at 4867-5295, 1049-1417 and 543-709 y cal. BP. Therefore, hydrothermal explosions arise from the self-sealing of the Acoculco geothermal system, involving a natural hazard that could affect future geothermal-power infrastructure.

Scenario simulation based assessment of subsurface energy storage

NASA Astrophysics Data System (ADS)

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

2014-12-01

Energy production from renewable sources such as solar or wind power is characterized by temporally varying power supply. The politically intended transition towards renewable energies in Germany („Energiewende") hence requires the installation of energy storage technologies to compensate for the fluctuating production. In this context, subsurface energy storage represents a viable option due to large potential storage capacities and the wide prevalence of suited geological formations. Technologies for subsurface energy storage comprise cavern or deep porous media storage of synthetic hydrogen or methane from electrolysis and methanization, or compressed air, as well as heat storage in shallow or moderately deep porous formations. Pressure build-up, fluid displacement or temperature changes induced by such operations may affect local and regional groundwater flow, geomechanical behavior, groundwater geochemistry and microbiology. Moreover, subsurface energy storage may interact and possibly be in conflict with other "uses" like drinking water abstraction or ecological goods and functions. An utilization of the subsurface for energy storage therefore requires an adequate system and process understanding for the evaluation and assessment of possible impacts of specific storage operations on other types of subsurface use, the affected environment and protected entities. This contribution presents the framework of the ANGUS+ project, in which tools and methods are developed for these types of assessments. Synthetic but still realistic scenarios of geological energy storage are derived and parameterized for representative North German storage sites by data acquisition and evaluation, and experimental work. Coupled numerical hydraulic, thermal, mechanical and reactive transport (THMC) simulation tools are developed and applied to simulate the energy storage and subsurface usage scenarios, which are analyzed for an assessment and generalization of the imposed THMC-processes, mutual effects and influences on protected entities. The scenario analyses allow the deduction of monitoring concepts as well as a first methodology for large scale spatial planning of the geological subsurface. This concept is illustrated for different storage options and their impacts in space and time.

Eastern Pacific tropical cyclones intensified by El Niño delivery of subsurface ocean heat.

PubMed

Jin, F-F; Boucharel, J; Lin, I-I

2014-12-04

The El Niño Southern Oscillation (ENSO) creates strong variations in sea surface temperature in the eastern equatorial Pacific, leading to major climatic and societal impacts. In particular, ENSO influences the yearly variations of tropical cyclone (TC) activities in both the Pacific and Atlantic basins through atmospheric dynamical factors such as vertical wind shear and stability. Until recently, however, the direct ocean thermal control of ENSO on TCs has not been taken into consideration because of an apparent mismatch in both timing and location: ENSO peaks in winter and its surface warming occurs mostly along the Equator, a region without TC activity. Here we show that El Niño--the warm phase of an ENSO cycle--effectively discharges heat into the eastern North Pacific basin two to three seasons after its wintertime peak, leading to intensified TCs. This basin is characterized by abundant TC activity and is the second most active TC region in the world. As a result of the time involved in ocean transport, El Niño's equatorial subsurface 'heat reservoir', built up in boreal winter, appears in the eastern North Pacific several months later during peak TC season (boreal summer and autumn). By means of this delayed ocean transport mechanism, ENSO provides an additional heat supply favourable for the formation of strong hurricanes. This thermal control on intense TC variability has significant implications for seasonal predictions and long-term projections of TC activity over the eastern North Pacific.

An experimental investigation of pulsed laser-assisted machining of AISI 52100 steel

NASA Astrophysics Data System (ADS)

Panjehpour, Afshin; Soleymani Yazdi, Mohammad R.; Shoja-Razavi, Reza

2014-11-01

Grinding and hard turning are widely used for machining of hardened bearing steel parts. Laser-assisted machining (LAM) has emerged as an efficient alternative to grinding and hard turning for hardened steel parts. In most cases, continuous-wave lasers were used as a heat source to cause localized heating prior to material removal by a cutting tool. In this study, an experimental investigation of pulsed laser-assisted machining of AISI 52100 bearing steel was conducted. The effects of process parameters (i.e., laser mean power, pulse frequency, pulse energy, cutting speed and feed rate) on state variables (i.e., material removal temperature, specific cutting energy, surface roughness, microstructure, tool wear and chip formation) were investigated. At laser mean power of 425 W with frequency of 120 Hz and cutting speed of 70 m/min, the benefit of LAM was shown by 25% decrease in specific cutting energy and 18% improvement in surface roughness, as compared to those of the conventional machining. It was shown that at constant laser power, the increase of laser pulse energy causes the rapid increase in tool wear rate. Pulsed laser allowed efficient control of surface temperature and heat penetration in material removal region. Examination of the machined subsurface microstructure and microhardness profiles showed no change under LAM and conventional machining. Continuous chips with more uniform plastic deformation were produced in LAM.

Impacts of convection on high-temperature aquifer thermal energy storage

NASA Astrophysics Data System (ADS)

Beyer, Christof; Hintze, Meike; Bauer, Sebastian

2016-04-01

Seasonal subsurface heat storage is increasingly used in order to overcome the temporal disparities between heat production from renewable sources like solar thermal installations or from industrial surplus heat and the heat demand for building climatisation or hot water supply. In this context, high-temperature aquifer thermal energy storage (ATES) is a technology to efficiently store and retrieve large amounts of heat using groundwater wells in an aquifer to inject or withdraw hot or cold water. Depending on the local hydrogeology and temperature amplitudes during high-temperature ATES, density differences between the injected hot water and the ambient groundwater may induce significant convective flow components in the groundwater flow field. As a consequence, stored heat may accumulate at the top of the storage aquifer which reduces the heat recovery efficiency of the ATES system. Also, an accumulation of heat at the aquifer top will induce increased emissions of heat to overlying formations with potential impacts on groundwater quality outside of the storage. This work investigates the impacts of convective heat transport on the storage efficiency of a hypothetical high-temperature ATES system for seasonal heat storage as well as heat emissions to neighboring formations by numerical scenario simulations. The coupled groundwater flow and heat transport code OpenGeoSys is used to simulate a medium scale ATES system operating in a sandy aquifer of 20 m thickness with an average groundwater temperature of 10°C and confining aquicludes at top and bottom. Seasonal heat storage by a well doublet (i.e. one fully screened "hot" and "cold" well, respectively) is simulated over a period of 10 years with biannual injection / withdrawal cycles at pumping rates of 15 m³/h and for different scenarios of the temperature of the injected water (20, 35, 60 and 90 °C). Simulation results show, that for the simulated system significant convective heat transport sets in when injection temperatures exceed 35°C. Convection results in an accumulation of heat below the upper confining layer. The consequential increase of the heat plume contact area with this formation results in increased conductive heat transfer. Also, thermal gradients between the heat plume and the ambient groundwater increase with injection temperature, which increases heat conduction within the aquifer. Both effects reduce the thermal recovery of the ATES system. At the end of the 10th injection / withdrawal cycle the efficiency of thermal recovery thus reaches about 76 % for the 20°C scenario, 74% for 35°C, 71 % for 60°C and 66 % for the 90 °C scenario. Sensitivity analysis indicates that permeability in horizontal and vertical directions are controlling factors for the extent of convective heat displacement. Also, heat plume dimensions are influenced by permeability, and to a lesser extent by heat capacity and porosity of the aquifer. The planning of high-temperature ATES at a specific site hence requires a careful investigation of hydraulic and heat transport properties. Acknowledgments: This work is part of the ANGUS+ project (www.angusplus.de) and funded by the German Federal Ministry of Education and Research (BMBF) as part of the energy storage initiative "Energiespeicher".

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

EPA Science Inventory

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

Method for determining depth and shape of a sub-surface conductive object

NASA Astrophysics Data System (ADS)

Lee, D. O.; Montoya, P. C.; Wayland, J. R., Jr.

1984-06-01

The depth to and size of an underground object may be determined by sweeping a controlled source audio magnetotelluric (CSAMT) signal and locating a peak response when the receiver spans the edge of the object. The depth of the object is one quarter wavelength in the subsurface media of the frequency of the peak.

Enhancing management of fall-applied poultry litter with cover crop and subsurface band placement in no-till cotton

USDA-ARS?s Scientific Manuscript database

Whether yield reduction risk of cotton fertilized with fall-applied poultry litter in regions with warm fall or winter months can be minimized by applying the litter in subsurface bands in conjunction with winter cover crop is unknown. A field study was conducted in Mississippi to test whether litte...

A one-dimensional model of subsurface hillslope flow

Treesearch

Jason C. Fisher

1997-01-01

Abstract - A one-dimensional, finite difference model of saturated subsurface flow within a hillslope was developed. The model uses rainfall, elevation data, a hydraulic conductivity, and a storage coefficient to predict the saturated thickness in time and space. The model was tested against piezometric data collected in a swale located in the headwaters of the North...

Effect of replacing surface inlets with blind or gravel inlets on sediment and phosphorus subsurface drainage losses

USDA-ARS?s Scientific Manuscript database

Open surface inlets that connect to subsurface tile drainage systems provide a direct pathway for sediment, nutrients, and agrochemicals to surface waters. This study was conducted to determine whether modifying open inlets by burying them in gravel capped with 30 cm of sandy clay loam soil or in ve...

Accurate modeling and inversion of electrical resistivity data in the presence of metallic infrastructure with known location and dimension

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

Johnson, Timothy C.; Wellman, Dawn M.

2015-06-26

Electrical resistivity tomography (ERT) has been widely used in environmental applications to study processes associated with subsurface contaminants and contaminant remediation. Anthropogenic alterations in subsurface electrical conductivity associated with contamination often originate from highly industrialized areas with significant amounts of buried metallic infrastructure. The deleterious influence of such infrastructure on imaging results generally limits the utility of ERT where it might otherwise prove useful for subsurface investigation and monitoring. In this manuscript we present a method of accurately modeling the effects of buried conductive infrastructure within the forward modeling algorithm, thereby removing them from the inversion results. The method ismore » implemented in parallel using immersed interface boundary conditions, whereby the global solution is reconstructed from a series of well-conditioned partial solutions. Forward modeling accuracy is demonstrated by comparison with analytic solutions. Synthetic imaging examples are used to investigate imaging capabilities within a subsurface containing electrically conductive buried tanks, transfer piping, and well casing, using both well casings and vertical electrode arrays as current sources and potential measurement electrodes. Results show that, although accurate infrastructure modeling removes the dominating influence of buried metallic features, the presence of metallic infrastructure degrades imaging resolution compared to standard ERT imaging. However, accurate imaging results may be obtained if electrodes are appropriately located.« less

Sensitivity of transpiration to subsurface properties: Exploration with a 1-D model

DOE PAGES

Vrettas, Michail D.; Fung, Inez Y.

2017-05-04

The amount of moisture transpired by vegetation is critically tied to the moisture supply accessible to the root zone. In a Mediterranean climate, integrated evapotranspiration (ET) is typically greater in the dry summer when there is an uninterrupted period of high insolation. We present a 1-D model to explore the subsurface factors that may sustain ET through the dry season. The model includes a stochastic parameterization of hydraulic conductivity, root water uptake efficiency, and hydraulic redistribution by plant roots. Model experiments vary the precipitation, the magnitude and seasonality of ET demand, as well as rooting profiles and rooting depths ofmore » the vegetation. The results show that the amount of subsurface moisture remaining at the end of the wet winter is determined by the competition among abundant precipitation input, fast infiltration, and winter ET demand. The weathered bedrock retains math formula of the winter rain and provides a substantial moisture reservoir that may sustain ET of deep-rooted (>8 m) trees through the dry season. A small negative feedback exists in the root zone, where the depletion of moisture by ET decreases hydraulic conductivity and enhances the retention of moisture. Hence, hydraulic redistribution by plant roots is impactful in a dry season, or with a less conductive subsurface. Suggestions for implementing the model in the CESM are discussed.« less

The Hidden Magnetic Field of the Young Neutron Star in Kesteven 79

NASA Astrophysics Data System (ADS)

Shabaltas, Natalia; Lai, Dong

2012-04-01

Recent observations of the central compact object in the Kesteven 79 supernova remnant show that this neutron star (NS) has a weak dipole magnetic field (a few × 1010 G) but an anomalously large (~64%) pulse fraction in its surface X-ray emission. We explore the idea that a substantial sub-surface magnetic field exists in the NS crust, which produces diffuse hot spots on the stellar surface due to anisotropic heat conduction, and gives rise to the observed X-ray pulsation. We develop a general-purpose method, termed "Temperature Template with Full Transport" (TTFT), that computes the synthetic pulse profile of surface X-ray emission from NSs with arbitrary magnetic field and surface temperature distributions, taking into account magnetic atmosphere opacities, beam pattern, vacuum polarization, and gravitational light bending. We show that a crustal toroidal magnetic field of order a few × 1014 G or higher, varying smoothly across the crust, can produce sufficiently distinct surface hot spots to generate the observed pulse fraction in the Kes 79 NS. This result suggests that substantial sub-surface magnetic fields, much stronger than the "visible" dipole fields, may be buried in the crusts of some young NSs, and such hidden magnetic fields can play an important role in their observational manifestations. The general TTFT tool we have developed can also be used for studying radiation from other magnetic NSs.

Resistivity structures across the Humboldt River basin, north-central Nevada

USGS Publications Warehouse

Rodriguez, Brian D.; Williams, Jackie M.

2002-01-01

Magnetotelluric data collected along five profiles show deep resistivity structures beneath the Battle Mountain-Eureka and Carlin gold trends in north-central Nevada, which appear consistent with tectonic breaks in the crust that possibly served as channels for hydrothermal fluids. It seems likely that gold deposits along these linear trends were, therefore, controlled by deep regional crustal fault systems. Two-dimensional resistivity modeling of the magnetotelluric data generally show resistive (30 to 1,000 ohm-m) crustal blocks broken by sub-vertical, two-dimensional, conductive (1 to 10 ohmm) zones that are indicative of large-scale crustal fault zones. These inferred fault zones are regional in scale, trend northeast-southwest, north-south, and northwest-southeast, and extend to mid-crustal (20 km) depths. The conductors are about 2- to 15-km wide, extend from about 1 to 4 km below the surface to about 20 km depth, and show two-dimensional electrical structure. By connecting the locations of similar trending conductors together, individual regional crustal fault zones within the upper crust can be inferred that range from about 4- to 10-km wide and about 30- to 150-km long. One of these crustal fault zones coincides with the Battle Mountain-Eureka mineral trend. The interpreted electrical property sections also show regional changes in the resistive crust from south to north. Most of the subsurface in the upper 20 km beneath Reese River Valley and southern Boulder Valley are underlain by rock that is generally more conductive than the subsurface beneath Kelly Creek Basin and northern Boulder Valley. This suggests that either elevated-temperature or high-salinity fluids, alteration, or carbonaceous rocks are more pervasive in the more conductive area (Battle Mountain Heat-Flow High), which implies that the crust beneath these valleys is either more fractured or has more carbonaceous rocks than in the area surveyed along the 41st parallel.

PFLOTRAN-E4D: A parallel open source PFLOTRAN module for simulating time-lapse electrical resistivity data

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

Johnson, Timothy C.; Hammond, Glenn E.; Chen, Xingyuan

Time-lapse electrical resistivity tomography (ERT) is finding increased application for remotely monitoring processes occurring in the near subsurface in three-dimensions (i.e. 4D monitoring). However, there are few codes capable of simulating the evolution of subsurface resistivity and corresponding tomographic measurements arising from a particular process, particularly in parallel and with an open source license. Herein we describe and demonstrate an electrical resistivity tomography module for the PFLOTRAN subsurface flow and reactive transport simulation code, named PFLOTRAN-E4D. The PFLOTRAN-E4D module operates in parallel using a dedicated set of compute cores in a master-slave configuration. At each time step, the master processesmore » receives subsurface states from PFLOTRAN, converts those states to bulk electrical conductivity, and instructs the slave processes to simulate a tomographic data set. The resulting multi-physics simulation capability enables accurate feasibility studies for ERT imaging, the identification of the ERT signatures that are unique to a given process, and facilitates the joint inversion of ERT data with hydrogeological data for subsurface characterization. PFLOTRAN-E4D is demonstrated herein using a field study of stage-driven groundwater/river water interaction ERT monitoring along the Columbia River, Washington, USA. Results demonstrate the complex nature of subsurface electrical conductivity changes, in both the saturated and unsaturated zones, arising from river stage fluctuations and associated river water intrusion into the aquifer. Furthermore, the results also demonstrate the sensitivity of surface based ERT measurements to those changes over time.« less

PFLOTRAN-E4D: A parallel open source PFLOTRAN module for simulating time-lapse electrical resistivity data

DOE PAGES

Johnson, Timothy C.; Hammond, Glenn E.; Chen, Xingyuan

2016-09-22

Time-lapse electrical resistivity tomography (ERT) is finding increased application for remotely monitoring processes occurring in the near subsurface in three-dimensions (i.e. 4D monitoring). However, there are few codes capable of simulating the evolution of subsurface resistivity and corresponding tomographic measurements arising from a particular process, particularly in parallel and with an open source license. Herein we describe and demonstrate an electrical resistivity tomography module for the PFLOTRAN subsurface flow and reactive transport simulation code, named PFLOTRAN-E4D. The PFLOTRAN-E4D module operates in parallel using a dedicated set of compute cores in a master-slave configuration. At each time step, the master processesmore » receives subsurface states from PFLOTRAN, converts those states to bulk electrical conductivity, and instructs the slave processes to simulate a tomographic data set. The resulting multi-physics simulation capability enables accurate feasibility studies for ERT imaging, the identification of the ERT signatures that are unique to a given process, and facilitates the joint inversion of ERT data with hydrogeological data for subsurface characterization. PFLOTRAN-E4D is demonstrated herein using a field study of stage-driven groundwater/river water interaction ERT monitoring along the Columbia River, Washington, USA. Results demonstrate the complex nature of subsurface electrical conductivity changes, in both the saturated and unsaturated zones, arising from river stage fluctuations and associated river water intrusion into the aquifer. Furthermore, the results also demonstrate the sensitivity of surface based ERT measurements to those changes over time.« less

Exploring Subsurface Geology Using Radar Techniques: Experiments in Sahara and Consequences for Mars Exploration

NASA Astrophysics Data System (ADS)

Paillou, P.; Grandjean, G.; Heggy, E.; Farr, T.

2004-05-01

For several years, we have conducted a quantitative study of radar penetration performances in various desert arid environments. This study combines both SAR (Synthetic Aperture Radar) imaging from orbital and airborne platforms and in situ GPR (Ground Penetrating Radar) measurements. Laboratory characterization of various minerals and rocks are used as input to electromagnetic models such as IEM (Integral Equation Model) and FDTD (Finite Difference Time Domain) that describe the subsurface scattering process for inversion purposes. Several test sites were explored, mainly the Sahara. Our first experiment was realized in Republic of Djibouti, an arid volcanic area which is a good analog to Mars. We observed a very little radar penetration there because of the presence of iron oxides and salts in the subsurface that make the soil conductive [Paillou et al., GRL, 2001]. A more favorable site for radar penetration was then explored in southern Egypt: the Bir Safsaf area where buried river channels were discovered using orbital SAR images. We showed how to combine SAR and GPR in order to obtain a complete description of subsurface geology down to several meters [Paillou et al., IEEE TGRS, 2003]. Such field experiments were the basis for more systematic laboratory measurements of the electromagnetic properties of various rocks and minerals which were used in numerical models in order to simulate the performances of future Martian radars, e.g. MARSIS and NETLANDER low frequency radars [Heggy et al., Icarus, 2001; Berthelier et al., JGR, 2003; Heggy et al., JGR, 2003]. More recently, new explorations were conducted in Mauritania in order to demonstrate radar capacities for geologic mapping [Grandjean et al., Coll. Afr. Geol., 2004] and in Libya where radar discovered a double impact crater in the southern desert [Paillou et al., C.R. Geoscience, 2003]. More local radar experiments were also conducted on a test site located in France, the Pyla sand dune, where we observed and modeled a radar signature of subsurface water [Grandjean et al., IEEE TGRS, 2001; Paillou et al., IGARSS'03, 2003]. All of these results shall be used in the context of "terrestrial analogs to Mars" studies in order to prepare for future Mars exploration using radars [Farr et al., Planet. Dec. Study, 2002; Paillou et al., 35th LPSC, 2004]: it concerns both GPR instruments onboard rovers and landers devoted to the exploration of the deep subsurface [Berthelier at al., ESA Pasteur, 2003] and SAR imaging systems onboard orbital platforms for global mapping of the shallow subsurface geology [Paillou et al., Conf. Water Mars, 2001].

A continuum model for meltwater flow through compacting snow

NASA Astrophysics Data System (ADS)

Meyer, Colin R.; Hewitt, Ian J.

2017-12-01

Meltwater is produced on the surface of glaciers and ice sheets when the seasonal energy forcing warms the snow to its melting temperature. This meltwater percolates into the snow and subsequently runs off laterally in streams, is stored as liquid water, or refreezes, thus warming the subsurface through the release of latent heat. We present a continuum model for the percolation process that includes heat conduction, meltwater percolation and refreezing, as well as mechanical compaction. The model is forced by surface mass and energy balances, and the percolation process is described using Darcy's law, allowing for both partially and fully saturated pore space. Water is allowed to run off from the surface if the snow is fully saturated. The model outputs include the temperature, density, and water-content profiles and the surface runoff and water storage. We compare the propagation of freezing fronts that occur in the model to observations from the Greenland Ice Sheet. We show that the model applies to both accumulation and ablation areas and allows for a transition between the two as the surface energy forcing varies. The largest average firn temperatures occur at intermediate values of the surface forcing when perennial water storage is predicted.

The influence of thermal inertia on Mars' seasonal pressure variation and the effect of the weather component

NASA Technical Reports Server (NTRS)

Wood, S. E.; Paige, D. A.

1993-01-01

Using a Leighton-Murray type diurnal and seasonal Mars thermal model, we found that it is possible to reproduce the seasonal variation in daily-averaged pressures (approximately 680-890 Pa) measured by Viking Lander 1 (VL1), during years without global dust storms, with a standard deviation of less than 5 Pa. In this simple model, surface CO2, frost condensation, and sublimation rates at each latitude are determined by the net effects of radiation, latent heat, and heat conduction in subsurface soil layers. An inherent assumption of our model is that the seasonal pressure variation is due entirely to the exchange of mass between the atmosphere and polar caps. However, the results of recent Mars GCM modeling have made it clear that there is a significant dynamical contribution to the seasonal pressure variation. This 'weather' component is primarily due to large-scale changes in atmospheric circulation, and its magnitude depends somewhat on the dust content of the atmosphere. The overall form of the theoretical weather component at the location of VL1, as calculated by the AMES GCM, remains the same over the typical range of Mars dust opacities.

Imaging Preferential Flow Pathways of Contaminants from Passive Acid Mine Drainage Mitigation Sites Using Electrical Resistivity

NASA Astrophysics Data System (ADS)

Kelley, N.; Mount, G.; Terry, N.; Herndon, E.; Singer, D. M.

2017-12-01

The Critical Zone represents the surficial and shallow layer of rock, air, water, and soil where most interactions between living organisms and the Earth occur. Acid mine drainage (AMD) resulting from coal extraction can influence both biological and geochemical processes across this zone. Conservative estimates suggest that more than 300 million gallons of AMD are released daily, making this acidic solution of water and contaminants a common issue in areas with legacy or current coal extraction. Electrical resistivity imaging (ERI) provides a rapid and minimally invasive method to identify and monitor contaminant pathways from AMD remediation systems in the subsurface of the Critical Zone. The technique yields spatially continuous data of subsurface resistivity that can be inverted to determine electrical conductivity as a function of depth. Since elevated concentrations of heavy metals can directly influence soil conductivity, ERI data can be used to trace the flow pathways or perhaps unknown mine conduits and transport of heavy metals through the subsurface near acid mine drainage sources. This study aims to examine preferential contaminant migration from those sources through substrate pores, fractures, and shallow mine workings in the near subsurface surrounding AMD sites in eastern Ohio and western Pennsylvania. We utilize time lapse ERI measures during different hydrologic conditions to better understand the variability of preferential flow pathways in relation to changes in stage and discharge within the remediation systems. To confirm ERI findings, and provide constraint to geochemical reactions occurring in the shallow subsurface, we conducted Inductively Coupled Plasma (ICP) spectrometry analysis of groundwater samples from boreholes along the survey transects. Through these combined methods, we can provide insight into the ability of engineered systems to contain and isolate metals in passive acid mine drainage treatment systems.

Incorporating Water Boiling in the Numerical Modelling of Thermal Remediation by Electrical Resistance Heating

NASA Astrophysics Data System (ADS)

Molnar, I. L.; Krol, M.; Mumford, K. G.

2017-12-01

Developing numerical models for subsurface thermal remediation techniques - such as Electrical Resistive Heating (ERH) - that include multiphase processes such as in-situ water boiling, gas production and recovery has remained a significant challenge. These subsurface gas generation and recovery processes are driven by physical phenomena such as discrete and unstable gas (bubble) flow as well as water-gas phase mass transfer rates during bubble flow. Traditional approaches to multiphase flow modeling soil remain unable to accurately describe these phenomena. However, it has been demonstrated that Macroscopic Invasion Percolation (MIP) can successfully simulate discrete and unstable gas transport1. This has lead to the development of a coupled Electro Thermal-MIP Model2 (ET-MIP) capable of simulating multiple key processes in the thermal remediation and gas recovery process including: electrical heating of soil and groundwater, water flow, geological heterogeneity, heating-induced buoyant flow, water boiling, gas bubble generation and mobilization, contaminant mass transport and removal, and additional mechanisms such as bubble collapse in cooler regions. This study presents the first rigorous validation of a coupled ET-MIP model against two-dimensional water boiling and water/NAPL co-boiling experiments3. Once validated, the model was used to explore the impact of water and co-boiling events and subsequent gas generation and mobilization on ERH's ability to 1) generate, expand and mobilize gas at boiling and NAPL co-boiling temperatures, 2) efficiently strip contaminants from soil during both boiling and co-boiling. In addition, a quantification of the energy losses arising from steam generation during subsurface water boiling was examined with respect to its impact on the efficacy of thermal remediation. While this study specifically targets ERH, the study's focus on examining the fundamental mechanisms driving thermal remediation (e.g., water boiling) renders these results applicable to a wide range of thermal and gas-based remediation techniques. 1. Mumford, K. G., et al. (2010), Adv. Water Resour. 2010, 33 (4), 504-513. 2. Krol, M. M., et al. (2011), Adv. Water Resour. 2011, 34 (4), 537-549. 3. Hegele, P. R. and Mumford, K. G. Journal of Contaminant Hydrology 2014, 165, 24-36.

Uranium Biomineralization by Natural Microbial Phosphatase Activities in the Subsurface

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

Sobecky, Patricia A.

2015-04-06

In this project, inter-disciplinary research activities were conducted in collaboration among investigators at The University of Alabama (UA), Georgia Institute of Technology (GT), Lawrence Berkeley National Laboratory (LBNL), Brookhaven National Laboratory (BNL), the DOE Joint Genome Institute (JGI), and the Stanford Synchrotron Radiation Light source (SSRL) to: (i) confirm that phosphatase activities of subsurface bacteria in Area 2 and 3 from the Oak Ridge Field Research Center result in solid U-phosphate precipitation in aerobic and anaerobic conditions; (ii) investigate the eventual competition between uranium biomineralization via U-phosphate precipitation and uranium bioreduction; (iii) determine subsurface microbial community structure changes of Areamore » 2 soils following organophosphate amendments; (iv) obtain the complete genome sequences of the Rahnella sp. Y9-602 and the type-strain Rahnella aquatilis ATCC 33071 isolated from these soils; (v) determine if polyphosphate accumulation and phytate hydrolysis can be used to promote U(VI) biomineralization in subsurface sediments; (vi) characterize the effect of uranium on phytate hydrolysis by a new microorganism isolated from uranium-contaminated sediments; (vii) utilize positron-emission tomography to label and track metabolically-active bacteria in soil columns, and (viii) study the stability of the uranium phosphate mineral product. Microarray analyses and mineral precipitation characterizations were conducted in collaboration with DOE SBR-funded investigators at LBNL. Thus, microbial phosphorus metabolism has been shown to have a contributing role to uranium immobilization in the subsurface.« less

A high frequency electromagnetic impedance imaging system

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

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

2003-01-15

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

Shallow Aquifer Vulnerability From Subsurface Fluid Injection at a Proposed Shale Gas Hydraulic Fracturing Site

NASA Astrophysics Data System (ADS)

Wilson, M. P.; Worrall, F.; Davies, R. J.; Hart, A.

2017-11-01

Groundwater flow resulting from a proposed hydraulic fracturing (fracking) operation was numerically modeled using 91 scenarios. Scenarios were chosen to be a combination of hydrogeological factors that a priori would control the long-term migration of fracking fluids to the shallow subsurface. These factors were induced fracture extent, cross-basin groundwater flow, deep low hydraulic conductivity strata, deep high hydraulic conductivity strata, fault hydraulic conductivity, and overpressure. The study considered the Bowland Basin, northwest England, with fracking of the Bowland Shale at ˜2,000 m depth and the shallow aquifer being the Sherwood Sandstone at ˜300-500 m depth. Of the 91 scenarios, 73 scenarios resulted in tracked particles not reaching the shallow aquifer within 10,000 years and 18 resulted in travel times less than 10,000 years. Four factors proved to have a statistically significant impact on reducing travel time to the aquifer: increased induced fracture extent, absence of deep high hydraulic conductivity strata, relatively low fault hydraulic conductivity, and magnitude of overpressure. Modeling suggests that high hydraulic conductivity formations can be more effective barriers to vertical flow than low hydraulic conductivity formations. Furthermore, low hydraulic conductivity faults can result in subsurface pressure compartmentalization, reducing horizontal groundwater flow, and encouraging vertical fluid migration. The modeled worst-case scenario, using unlikely geology and induced fracture lengths, maximum values for strata hydraulic conductivity and with conservative tracer behavior had a particle travel time of 130 years to the base of the shallow aquifer. This study has identified hydrogeological factors which lead to aquifer vulnerability from shale exploitation.

THERMO-HYDRO-MECHANICAL MODELING OF WORKING FLUID INJECTION AND THERMAL ENERGY EXTRACTION IN EGS FRACTURES AND ROCK MATRIX

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

Robert Podgorney; Chuan Lu; Hai Huang

2012-01-01

Development of enhanced geothermal systems (EGS) will require creation of a reservoir of sufficient volume to enable commercial-scale heat transfer from the reservoir rocks to the working fluid. A key assumption associated with reservoir creation/stimulation is that sufficient rock volumes can be hydraulically fractured via both tensile and shear failure, and more importantly by reactivation of naturally existing fractures (by shearing), to create the reservoir. The advancement of EGS greatly depends on our understanding of the dynamics of the intimately coupled rock-fracture-fluid-heat system and our ability to reliably predict how reservoirs behave under stimulation and production. Reliable performance predictions ofmore » EGS reservoirs require accurate and robust modeling for strongly coupled thermal-hydrological-mechanical (THM) processes. Conventionally, these types of problems have been solved using operator-splitting methods, usually by coupling a subsurface flow and heat transport simulators with a solid mechanics simulator via input files. An alternative approach is to solve the system of nonlinear partial differential equations that govern multiphase fluid flow, heat transport, and rock mechanics simultaneously, using a fully coupled, fully implicit solution procedure, in which all solution variables (pressure, enthalpy, and rock displacement fields) are solved simultaneously. This paper describes numerical simulations used to investigate the poro- and thermal- elastic effects of working fluid injection and thermal energy extraction on the properties of the fractures and rock matrix of a hypothetical EGS reservoir, using a novel simulation software FALCON (Podgorney et al., 2011), a finite element based simulator solving fully coupled multiphase fluid flow, heat transport, rock deformation, and fracturing using a global implicit approach. Investigations are also conducted on how these poro- and thermal-elastic effects are related to fracture permeability evolution.« less

Alternate energy source usage for in situ heat treatment processes

DOEpatents

Stone, Jr., Francis Marion; Goodwin, Charles R [League City, TX; Richard, Jr., James

2011-03-22

Systems, methods, and heaters for treating a subsurface formation are described herein. At least one system for providing power to one or more subsurface heaters is described herein. The system may include an intermittent power source; a transformer coupled to the intermittent power source, and a tap controller coupled to the transformer. The transformer may be configured to transform power from the intermittent power source to power with appropriate operating parameters for the heaters. The tap controller may be configured to monitor and control the transformer so that a constant voltage is provided to the heaters from the transformer regardless of the load of the heaters and the power output provided by the intermittent power source.

TOUGHREACT: a new code of the TOUGH Family for Non-Isothermal multiphase reactive geochemical transport in variably saturated geologic media

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

Xu, Tianfu; Sonnenthal, Eric; Spycher, Nicolas

Coupled modeling of subsurface multiphase fluid and heat flow, solute transport and chemical reactions can be used for the assessment of acid mine drainage remediation, waste disposal sites, hydrothermal convection, contaminant transport, and groundwater quality. We have developed a comprehensive numerical simulator, TOUGHREACT, which considers non-isothermal multi-component chemical transport in both liquid and gas phases. A wide range of subsurface thermo-physical-chemical processes is considered under various thermohydrological and geochemical conditions of pressure, temperature, water saturation, and ionic strength. The code can be applied to one-, two- or three-dimensional porous and fractured media with physical and chemical heterogeneity.

Habitability of enceladus: planetary conditions for life.

PubMed

Parkinson, Christopher D; Liang, Mao-Chang; Yung, Yuk L; Kirschivnk, Joseph L

2008-08-01

The prolific activity and presence of a plume on Saturn's tiny moon Enceladus offers us a unique opportunity to sample the interior composition of an icy satellite, and to look for interesting chemistry and possible signs of life. Based on studies of the potential habitability of Jupiter's moon Europa, icy satellite oceans can be habitable if they are chemically mixed with the overlying ice shell on Myr time scales. We hypothesize that Enceladus' plume, tectonic processes, and possible liquid water ocean may create a complete and sustainable geochemical cycle that may allow it to support life. We discuss evidence for surface/ocean material exchange on Enceladus based on the amounts of silicate dust material present in the Enceladus' plume particles. Microphysical cloud modeling of Enceladus' plume shows that the particles originate from a region of Enceladus' near surface where the temperature exceeds 190 K. This could be consistent with a shear-heating origin of Enceladus' tiger stripes, which would indicate extremely high temperatures ( approximately 250-273 K) in the subsurface shear fault zone, leading to the generation of subsurface liquid water, chemical equilibration between surface and subsurface ices, and crustal recycling on a time scale of 1 to 5 Myr. Alternatively, if the tiger stripes form in a mid-ocean-ridge-type mechanism, a half-spreading rate of 1 m/year is consistent with the observed regional heat flux of 250 mW m(-2) and recycling of south polar terrain crust on a 1 to 5 Myr time scale as well.

The warming trend of ground surface temperature in the Choshui Alluvial Fan, western central Taiwan

NASA Astrophysics Data System (ADS)

Chen, W.; Chang, M.; Chen, J.; Lu, W.; Huang, C. C.; Wang, Y.

2013-12-01

Heat storage in subsurface of the continents forms a fundamental component of the global energy budget and plays an important role in the climate system. Several researches revealed that subsurface temperatures were being increased to 1.8-2.8°C higher in mean ground surface temperature (GST) for some Asian cities where are experiencing a rapid growth of population. Taiwan is a subtropic-tropic island with densely populated in the coastal plains surrounding its mountains. We investigate the subsurface temperature distribution and the borehole temperature-depth profiles by using groundwater monitoring wells in years 2000 and 2010. Our data show that the western central Taiwan plain also has been experiencing a warming trend but with a higher temperatures approximately 3-4 °C of GST during the last 250 yrs. We suggest that the warming were mostly due to the land change to urbanization and agriculture. The current GSTs from our wells are approximately 25.51-26.79 °C which are higher than the current surface air temperature (SAT) of 23.65 °C. Data from Taiwan's weather stations also show 1-1.5 °C higher for the GST than the SAT at neighboring stations. The earth surface heat balance data indicate that GST higher than SAT is reasonable. More researches are needed to evaluate the interaction of GST and SAT, and how a warming GST's impact to the SAT and the climate system of the Earth.

Nutrient Estimation Using Subsurface Sensing Methods

USDA-ARS?s Scientific Manuscript database

This report investigates the use of precision management techniques for measuring soil conductivity on feedlot surfaces to estimate nutrient value for crop production. An electromagnetic induction soil conductivity meter was used to collect apparent soil electrical conductivity (ECa) from feedlot p...

A new technology for determining transport parameters in porous media

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

Conca, J.L.; Wright, J.

The UFA Method can directly and rapidly measure transport parameters for any porous medium over a wide range of water contents and conditions. UFA results for subsurface sediments at a mixed-waste disposal site at the Hanford Site in Washington State provided the data necessary for detailed hydrostratigraphic mapping, subsurface flux and recharge distributions, and subsurface chemical mapping. Seven hundred unsaturated conductivity measurements along with pristine pore water extractions were obtained in only six months using the UFA. These data are used to provide realistic information to conceptual models, predictive models and restoration strategies.

Thermally driven advection for radioxenon transport from an underground nuclear explosion

NASA Astrophysics Data System (ADS)

Sun, Yunwei; Carrigan, Charles R.

2016-05-01

Barometric pumping is a ubiquitous process resulting in migration of gases in the subsurface that has been studied as the primary mechanism for noble gas transport from an underground nuclear explosion (UNE). However, at early times following a UNE, advection driven by explosion residual heat is relevant to noble gas transport. A rigorous measure is needed for demonstrating how, when, and where advection is important. In this paper three physical processes of uncertain magnitude (oscillatory advection, matrix diffusion, and thermally driven advection) are parameterized by using boundary conditions, system properties, and source term strength. Sobol' sensitivity analysis is conducted to evaluate the importance of all physical processes influencing the xenon signals. This study indicates that thermally driven advection plays a more important role in producing xenon signals than oscillatory advection and matrix diffusion at early times following a UNE, and xenon isotopic ratios are observed to have both time and spatial dependence.

Consensuses and discrepancies of basin-scale ocean heat content changes in different ocean analyses

NASA Astrophysics Data System (ADS)

Wang, Gongjie; Cheng, Lijing; Abraham, John; Li, Chongyin

2018-04-01

Inconsistent global/basin ocean heat content (OHC) changes were found in different ocean subsurface temperature analyses, especially in recent studies related to the slowdown in global surface temperature rise. This finding challenges the reliability of the ocean subsurface temperature analyses and motivates a more comprehensive inter-comparison between the analyses. Here we compare the OHC changes in three ocean analyses (Ishii, EN4 and IAP) to investigate the uncertainty in OHC in four major ocean basins from decadal to multi-decadal scales. First, all products show an increase of OHC since 1970 in each ocean basin revealing a robust warming, although the warming rates are not identical. The geographical patterns, the key modes and the vertical structure of OHC changes are consistent among the three datasets, implying that the main OHC variabilities can be robustly represented. However, large discrepancies are found in the percentage of basinal ocean heating related to the global ocean, with the largest differences in the Pacific and Southern Ocean. Meanwhile, we find a large discrepancy of ocean heat storage in different layers, especially within 300-700 m in the Pacific and Southern Oceans. Furthermore, the near surface analysis of Ishii and IAP are consistent with sea surface temperature (SST) products, but EN4 is found to underestimate the long-term trend. Compared with ocean heat storage derived from the atmospheric budget equation, all products show consistent seasonal cycles of OHC in the upper 1500 m especially during 2008 to 2012. Overall, our analyses further the understanding of the observed OHC variations, and we recommend a careful quantification of errors in the ocean analyses.

Design and Laboratory Validation of a Capacitive Sensor for Measuring the Recession of Thin-Layered Ablator

NASA Technical Reports Server (NTRS)

Noffz, Gregory K.; Bowman, Michael P.

1996-01-01

Flight vehicles are typically instrumented with subsurface thermocouples to estimate heat transfer at the surface using inverse analysis procedures. If the vehicle has an ablating heat shield, however, temperature time histories from subsurface thermocouples no longer provide enough information to estimate heat flux at the surface. In this situation, the geometry changes and thermal energy leaves the surface in the form of ablation products. The ablation rate is required to estimate heat transfer to the surface. A new concept for a capacitive sensor has been developed to measure ablator depth using the ablator's dielectric effect on a capacitor's fringe region. Relying on the capacitor's fringe region enables the gage to be flush mounted in the vehicle's permanent structure and not intrude into the ablative heat shield applied over the gage. This sensor's design allows nonintrusive measurement of the thickness of dielectric materials, in particular, the recession rates of low-temperature ablators applied in thin (0.020 to 0.060 in. (0.05 to 0.15 mm)) layers. Twenty capacitive gages with 13 different sensing element geometries were designed, fabricated, and tested. A two-dimensional finite-element analysis was performed on several candidate geometries. Calibration procedures using ablator-simulating shims are described. A one-to-one correspondence between system output and dielectric material thickness was observed out to a thickness of 0.055 in. (1.4 mm) for a material with a permittivity about three times that of air or vacuum. A novel method of monitoring the change in sensor capacitance was developed. This technical memorandum suggests further improvements in gage design and fabrication techniques.

In situ mitigation of subsurface and peripheral focused ion beam damage via simultaneous pulsed laser heating

DOE PAGES

Stanford, Michael G.; Lewis, Brett B.; Iberi, Vighter O.; ...

2016-02-16

Focused helium and neon ion (He(+)/Ne(+) ) beam processing has recently been used to push resolution limits of direct-write nanoscale synthesis. The ubiquitous insertion of focused He(+) /Ne(+) beams as the next-generation nanofabrication tool-of-choice is currently limited by deleterious subsurface and peripheral damage induced by the energetic ions in the underlying substrate. The in situ mitigation of subsurface damage induced by He(+)/Ne(+) ion exposures in silicon via a synchronized infrared pulsed laser-assisted process is demonstrated. The pulsed laser assist provides highly localized in situ photothermal energy which reduces the implantation and defect concentration by greater than 90%. The laser-assisted exposuremore » process is also shown to reduce peripheral defects in He(+) patterned graphene, which makes this process an attractive candidate for direct-write patterning of 2D materials. In conclusion, these results offer a necessary solution for the applicability of high-resolution direct-write nanoscale material processing via focused ion beams.« less

Temperature limited heaters using phase transformation of ferromagnetic material

DOEpatents

Vitek, John Michael [Oak Ridge, TN; Brady, Michael Patrick [Oak Ridge, TN

2009-10-06

Systems, methods, and heaters for treating a subsurface formation are described herein. Systems and methods for making heaters are described herein. At least one heater includes a ferromagnetic conductor and an electrical conductor. The electrical conductor is electrically coupled to the ferromagnetic conductor. The heater provides a first amount of heat at a lower temperature. The heater may provide a second reduced amount of heat when the heater reaches a selected temperature, or enters a selected temperature range, at which the ferromagnetic conductor undergoes a phase transformation.

Method for determining depth and shape of a sub-surface conductive object

DOEpatents

Lee, D.O.; Montoya, P.C.; Wayland, Jr.

1984-06-27

The depth to and size of an underground object may be determined by sweeping a controlled source audio magnetotelluric (CSAMT) signal and locating a peak response when the receiver spans the edge of the object. The depth of the object is one quarter wavelength in the subsurface media of the frequency of the peak. 3 figures.

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

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

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

2004-06-16

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

Ten years of measurements and modeling of soil temperature changes and their effects on permafrost in Northwestern Alaska

NASA Astrophysics Data System (ADS)

Batir, Joseph F.; Hornbach, Matthew J.; Blackwell, David D.

2017-01-01

Multiple studies demonstrate Northwest Alaska and the Alaskan North Slope are warming. Melting permafrost causes surface destabilization and ecological changes. Here, we use thermistors permanently installed in 1996 in a borehole in northwestern Alaska to study past, present, and future ground and subsurface temperature change, and from this, forecast future permafrost degradation in the region. We measure and model Ground Surface Temperature (GST) warming trends for a 10 year period using equilibrium Temperature-Depth (TD) measurements from borehole T96-012, located near the Red Dog Mine in northwestern Alaska-part of the Arctic ecosystem where a continuous permafrost layer exists. Temperature measurements from 1996 to 2006 indicate the subsurface has clearly warmed at depths shallower than 70 m. Seasonal climate effects are visible in the data to a depth of 30 m based on a visible sinusoidal pattern in the TD plots that correlate with season patterns. Using numerical models constrained by thermal conductivity and temperature measurements at the site, we show that steady warming at depths of 30 to 70 m is most likely the direct result of longer term (decadal-scale) surface warming. The analysis indicates the GST in the region is warming at 0.44 ± 0.05 °C/decade, a value consistent with Surface Air Temperature (SAT) warming of 1.0 ± 0.8 °C/decade observed at Red Dog Mine, but with much lower uncertainty. The high annual variability in the SAT signal produces significant uncertainty in SAT trends. The high annual variability is filtered out of the GST signal by the low thermal diffusivity of the subsurface. Comparison of our results to recent permafrost monitoring studies suggests changes in latitude in the polar regions significantly impacts warming rates. North Slope average GST warming is 0.9 ± 0.5 °C/decade, double our observations at RDM, but within error. The RDM warming rate is within the warming variation observed in eastern Alaska, 0.36-0.71 °C/decade, which suggests changes in longitude produce a smaller impact but have warming variability likely related to ecosystem, elevation, microclimates, etc. changes. We also forward model future warming by assuming a 1D diffusive heat flow model and incorporating latent heat effects for permafrost melting. Our analysis indicates 1 to 4 m of loss at the upper permafrost boundary, a 145 ± 100% increase in the active layer thickness by 2055. If warming continues at a constant rate of 0.44 ± 0.05 °C/decade, we estimate the 125 m thick zone of permafrost at this site will completely melt by 2150. Permafrost is expected to melt by 2200, 2110, or 2080, if the rate of warming is altered to 0.25, 0.90, or 2.0 °C/decade, respectively, as an array of different climate models suggest. Since our model assumes no advection of heat (a more efficient heat transport mechanism), and no accelerated warming, our current prediction of complete permafrost loss by 2150 may overestimate the residence time of permafrost in this region of Northwest Alaska.

Improved Microseismicity Detection During Newberry EGS Stimulations

DOE Data Explorer

Templeton, Dennise

2013-10-01

Effective enhanced geothermal systems (EGS) require optimal fracture networks for efficient heat transfer between hot rock and fluid. Microseismic mapping is a key tool used to infer the subsurface fracture geometry. Traditional earthquake detection and location techniques are often employed to identify microearthquakes in geothermal regions. However, most commonly used algorithms may miss events if the seismic signal of an earthquake is small relative to the background noise level or if a microearthquake occurs within the coda of a larger event. Consequently, we have developed a set of algorithms that provide improved microearthquake detection. Our objective is to investigate the microseismicity at the DOE Newberry EGS site to better image the active regions of the underground fracture network during and immediately after the EGS stimulation. Detection of more microearthquakes during EGS stimulations will allow for better seismic delineation of the active regions of the underground fracture system. This improved knowledge of the reservoir network will improve our understanding of subsurface conditions, and allow improvement of the stimulation strategy that will optimize heat extraction and maximize economic return.

Improved Microseismicity Detection During Newberry EGS Stimulations

DOE Data Explorer

Templeton, Dennise

2013-11-01

Effective enhanced geothermal systems (EGS) require optimal fracture networks for efficient heat transfer between hot rock and fluid. Microseismic mapping is a key tool used to infer the subsurface fracture geometry. Traditional earthquake detection and location techniques are often employed to identify microearthquakes in geothermal regions. However, most commonly used algorithms may miss events if the seismic signal of an earthquake is small relative to the background noise level or if a microearthquake occurs within the coda of a larger event. Consequently, we have developed a set of algorithms that provide improved microearthquake detection. Our objective is to investigate the microseismicity at the DOE Newberry EGS site to better image the active regions of the underground fracture network during and immediately after the EGS stimulation. Detection of more microearthquakes during EGS stimulations will allow for better seismic delineation of the active regions of the underground fracture system. This improved knowledge of the reservoir network will improve our understanding of subsurface conditions, and allow improvement of the stimulation strategy that will optimize heat extraction and maximize economic return.

Exploring the Effects of Atmospheric Forcings on Evaporation: Experimental Integration of the Atmospheric Boundary Layer and Shallow Subsurface

PubMed Central

Smits, Kathleen; Eagen, Victoria; Trautz, Andrew

2015-01-01

Evaporation is directly influenced by the interactions between the atmosphere, land surface and soil subsurface. This work aims to experimentally study evaporation under various surface boundary conditions to improve our current understanding and characterization of this multiphase phenomenon as well as to validate numerical heat and mass transfer theories that couple Navier-Stokes flow in the atmosphere and Darcian flow in the porous media. Experimental data were collected using a unique soil tank apparatus interfaced with a small climate controlled wind tunnel. The experimental apparatus was instrumented with a suite of state of the art sensor technologies for the continuous and autonomous collection of soil moisture, soil thermal properties, soil and air temperature, relative humidity, and wind speed. This experimental apparatus can be used to generate data under well controlled boundary conditions, allowing for better control and gathering of accurate data at scales of interest not feasible in the field. Induced airflow at several distinct wind speeds over the soil surface resulted in unique behavior of heat and mass transfer during the different evaporative stages. PMID:26131928

Geological evidence for solid-state convection in Europa's ice shell.

PubMed

Pappalardo, R T; Head, J W; Greeley, R; Sullivan, R J; Pilcher, C; Schubert, G; Moore, W B; Carr, M H; Moore, J M; Belton, M J; Goldsby, D L

1998-01-22

The ice-rich surface of the jovian satellite Europa is sparsely cratered, suggesting that this moon might be geologically active today. Moreover, models of the satellite's interior indicate that tidal interactions with Jupiter might produce enough heat to maintain a subsurface liquid water layer. But the mechanisms of interior heat loss and resurfacing are currently unclear, as is the question of whether Europa has (or had at one time) a liquid water ocean. Here we report on the morphology and geological interpretation of distinct surface features-pits, domes and spots-discovered in high-resolution images of Europa obtained by the Galileo spacecraft. The features are interpreted as the surface manifestation of diapirs, relatively warm localized ice masses that have risen buoyantly through the subsurface. We find that the formation of the features can be explained by thermally induced solid-state convection within an ice shell, possibly overlying a liquid water layer. Our results are consistent with the possibility that Europa has a liquid water ocean beneath a surface layer of ice, but further tests and observations are needed to demonstrate this conclusively.

Tritium retention in reduced-activation ferritic/martensitic steels

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

Hatano, Y.; Abe, S.; Matsuyama, M.

Reduced-activation ferritic/martensitic (RAFM) steels are structural material candidates for breeding blankets of future fusion reactors. Therefore, tritium (T) retention in RAFM steels is an important problem in assessing the T inventory of blankets. In this study, specimens of RAFM steels were subjected to irradiation of 20 MeV W ions to 0.54 displacements per atom (dpa), exposure to high flux D plasmas at 400 and 600 K and that to pulsed heat loads. The specimens thus prepared were exposed to DT gas at 473 K. Despite severe modification in the surface morphology, heat loads had negligible effects on T retention. Significantmore » increase in T retention at the surface and/or subsurface was observed after D plasma exposure. However, T trapped at the surface/subsurface layer was easily removed by maintaining the specimens in the air at about 300 K. Displacement damage led to increase in T retention in the bulk due to the trapping effects of defects, and T trapped was stable at 300 K. It was therefore concluded that displacement damages had the largest influence on T retention under the present conditions.« less

Geological evidence for solid-state convection in Europa's ice shell

USGS Publications Warehouse

Pappalardo, R.T.; Head, J.W.; Greeley, R.; Sullivan, R.J.; Pilcher, C.; Schubert, G.; Moore, W.B.; Carr, M.H.; Moore, Johnnie N.; Belton, M.J.S.; Goldsby, D.L.

1998-01-01

The ice-rich surface of the jovian satellite Europa is sparsely cratered, suggesting that this moon might be geologically active today. Moreover, models of the satellite's interior indicate that tidal interactions with Jupiter might produce enough heat to maintain a subsurface liquid water layer. But the mechanisms of interior heat loss and resurfacing are currently unclear, as is the question of whether Europa has (or had at one time) a liquid water ocean. Here we report on the morphology and geological interpretation of distinct surface features-pits, domes and spots-discovered in high-resolution images of Europa obtained by the Galileo spacecraft. The features are interpreted as the surface manifestation of diapirs, relatively warm localized ice masses that have risen buoyantly through the subsurface. We find that the formation of the features can be explained by thermally induced solid-state convection within an ice shell, possibly overlying a liquid water layer. Our results are consistent with the possibility that Europa has a liquid water ocean beneath a surface layer of ice, but further tests and observations are needed to demonstrate this conclusively.

Lunar heat-flow experiment

NASA Technical Reports Server (NTRS)

Langseth, M. G.

1977-01-01

The principal components of the experiment were probes, each with twelve thermometers of exceptional accuracy and stability, that recorded temperature variations at the surface and in the regolith down to 2.5 m. The Apollo 15 experiment and the Apollo 17 probes recorded lunar surface and subsurface temperatures. These data provided a unique and valuable history of the interaction of solar energy with lunar surface and the effects of heat flowing from the deep interior out through the surface of the moon. The interpretation of these data resulted in a clearer definition of the thermal and mechanical properties of the upper two meters of lunar regolith, direct measurements of the gradient in mean temperature due to heat flow from the interior and a determination of the heat flow at the Apollo 15 and Apollo 17 sites.

Effects of Atmospheric Conditions and the Land/Atmospheric Interface on Transport of Chemical Vapors from Subsurface Sources

NASA Astrophysics Data System (ADS)

Rice, A. K.; Smits, K. M.; Cihan, A.; Howington, S. E.; Illangasekare, T. H.

2013-12-01

Understanding the movement of chemical vapors and gas through variably saturated soil subjected to atmospheric thermal and mass flux boundary conditions at the land/atmospheric interface is important to many applications, including landmine detection, methane leakage during natural gas production from shale and CO2 leakage from deep geologic storage. New, advanced technologies exist to sense chemical signatures and gas leakage at the land/atmosphere interface, but interpretation of sensor signals remains a challenge. Chemical vapors are subject to numerous interactions while migrating through the soil environment, masking source conditions. The process governing movement of gases through porous media is often assumed to be Fickian diffusion through the air phase with minimal quantification of other processes, such as convective gas flow and temporal or spatial variation in soil moisture. Vapor migration is affected by atmospheric conditions (e.g. humidity, temperature, wind velocity), soil thermal and hydraulic properties and contaminant properties, all of which are physically and thermodynamically coupled. The complex coupling of two drastically different flow regimes in the subsurface and atmosphere is commonly ignored in modeling efforts, or simplifying assumptions are made to treat the systems as de-coupled. Experimental data under controlled laboratory settings are lacking to refine the theory for proper coupling and complex treatment of vapor migration through porous media in conversation with atmospheric flow and climate variations. Improving fundamental understanding and accurate quantification of these processes is not feasible in field settings due to lack of controlled initial and boundary conditions and inability to fully characterize the subsurface at all relevant scales. The goal of this work is to understand the influence of changes in atmospheric conditions to transport of vapors through variably saturated soil. We have developed a tank apparatus with a network of soil and atmospheric sensors and a head space for air flow to simulate the atmospheric boundary layer. Experiments were performed under varying temperature values at the soil surface bounded by the atmospheric boundary layer. The model of Smits et al. [2011], accounting for non-equilibrium phase change and coupled heat, water vapor and liquid water flux through soil, was amended to include organic vapor in the gas phase and migration mechanisms often overlooked in models (thermal and Knudsen diffusion, density driven advection). Experimental results show increased vapor mass flux across the soil/atmospheric interface due to heat applied from the atmosphere and coupling of heat and mass transfer in the shallow subsurface for both steady and diurnal temperature patterns. Comparison of model results to experimental data shows dynamic interactions between transport in porous media and boundary conditions. Results demonstrate the value of considering interactions of the atmosphere and subsurface to better understand chemical gas transport through unsaturated soils and the land/atmospheric interface.

Heat Flow and Hydrologic Characteristics at the AND-1B borehole, ANDRILL McMurdo Ice Shelf Project, Antarctica

USGS Publications Warehouse

Morin, Roger H.; Williams, Trevor; Henry, Stuart; ,; Hansaraj, Dhiresh

2010-01-01

The Antarctic Drilling Program (ANDRILL) successfully drilled and cored a borehole, AND-1B, beneath the McMurdo Ice Shelf and into a flexural moat basin that surrounds Ross Island. Total drilling depth reached 1285 m below seafloor (mbsf) with 98 percent core recovery for the detailed study of glacier dynamics. With the goal of obtaining complementary information regarding heat flow and permeability, which is vital to understanding the nature of marine hydrogeologic systems, a succession of three temperature logs was recorded over a five-day span to monitor the gradual thermal recovery toward equilibrium conditions. These data were extrapolated to true, undisturbed temperatures, and they define a linear geothermal gradient of 76.7 K/km from the seafloor to 647 mbsf. Bulk thermal conductivities of the sedimentary rocks were derived from empirical mixing models and density measurements performed on core, and an average value of 1.5 W/mK ± 10 percent was determined. The corresponding estimate of heat flow at this site is 115 mW/m2. This value is relatively high but is consistent with other elevated heat-flow data associated with the Erebus Volcanic Province. Information regarding the origin and frequency of pathways for subsurface fluid flow is gleaned from drillers' records, complementary geophysical logs, and core descriptions. Only two prominent permeable zones are identified and these correspond to two markedly different features within the rift basin; one is a distinct lithostratigraphic subunit consisting of a thin lava flow and the other is a heavily fractured interval within a single thick subunit.

High-resolution cross-borehole thermal tracer testing in granite: preliminary field results

NASA Astrophysics Data System (ADS)

Brixel, Bernard; Klepikova, Maria; Jalali, Mohammadreza; Amann, Florian; Loew, Simon

2017-04-01

Understanding how heat is transported, stored and exchanged across fractured media is becoming increasingly relevant in our society, as manifested from the growing popularity of modern technologies relying on the subsurface to either source or store heat. One good example is the utilization of heat from deep hydrothermal or petrothermal systems to generate electricity for base load power generation, a technology also known as deep geothermal energy (DGE). While very attractive in principle, the number of geothermal fields producing economical levels of electricity to this day is still very limited - largely due to the difficulty of either locating deep reservoirs that are both sufficiently hot and permeable or, in the absence of the latter, creating them. In this context, the Swiss Competence Center for Energy Research - Supply of Electricity (SCCER - SoE) is carrying out an in situ stimulation and circulation (ISC) experiment at the Grimsel Test Site (GTS), an underground rock lab located in the Aar massif, in the Swiss Alps. The circulation experiment planned for the post-stimulation phase represents one of the key components of this experimental research program, and the outcome of this test is expected to ultimately provide key insights in the factors controlling the performance of enhanced geothermal reservoirs. Therefore, to support the design of this experiment, short-term thermal tracer tests (TTT) were conducted with the objective to (i) assess the feasibility of conducting TTTs in a relatively intact granite (where fluid flow is controlled by a limited number of discrete fractures); (ii) determine optimal experimental setups; and to ultimately (iii) monitor thermal breakthroughs at high spatial and temporal resolution, providing insights on heat transport and complementing the characterization of hydrogeological conditions carried out through conventional means (e.g. hydraulic and/or solute tracer tests). Presented herein are the results of a 10-day thermal tracer test conducted by continuously injecting water at 40°C (ambient groundwater temperatures average around 12-13 °C) across a discrete fractured zone, isolated with packers. Monitoring was achieved using a combination of discrete temperature sensors (PT1000) and FO DTS (Silixa XT system) deployed along a network of both packed-off and open boreholes situated approx. 6-20 m apart from the injection zone. Thermal breakthrough was observed in multiple boreholes, as early as 6-7 hours following the injection of hot water. The rate of increase in temperatures was observed to significantly diminish over time, allowing water in the fracture carrying the majority of heat to reach a temperature of 17°C at the closest observation location. Furthermore, temperature declined along the fracture length. These data allowed us identifying the precise location of conductive fractures, thereby improving our understanding of the connectivity structure of our experimental rock volume. In addition, these results provide significant insights on heat transport and the efficiency of heat-exchange between fractures and the surrounding rock mass at Grimsel.

Thermal conductivity of lunar regolith simulant JSC-1A under vacuum

NASA Astrophysics Data System (ADS)

Sakatani, Naoya; Ogawa, Kazunori; Arakawa, Masahiko; Tanaka, Satoshi

2018-07-01

Many air-less planetary bodies, including the Moon, asteroids, and comets, are covered by regolith. The thermal conductivity of the regolith is an essential parameter controlling the surface temperature variation. A thermal conductivity model applicable to natural soils as well as planetary surface regolith is required to analyze infrared remote sensing data. In this study, we investigated the temperature and compressional stress dependence of the thermal conductivity of the lunar regolith simulant JSC-1A, and the temperature dependence of sieved JSC-1A samples under vacuum conditions. We confirmed that a series of the experimental data for JSC-1A are fitted well by our analytical model of the thermal conductivity (Sakatani et al., 2017). Comparison with the calibration data of the sieved samples with those for original JSC-1A indicates that the thermal conductivity of natural samples with a wide grain size distribution can be modeled as mono-sized grains with a volumetric median size. The calibrated model can be used to estimate the volumetric median grain size from infrared remote sensing data. Our experiments and the calibrated model indicates that uncompressed JSC-1A has similar thermal conductivity to lunar top-surface materials, but the lunar subsurface thermal conductivity cannot be explained only by the effects of the density and self-weighted compressional stress. We infer that the nature of the lunar subsurface regolith grains is much different from JSC-1A and lunar top-surface regolith, and/or the lunar subsurface regolith is over-consolidated and the compressional stress higher than the hydrostatic pressure is stored in the lunar regolith layer.

Effect of soil property uncertainties on permafrost thaw projections: a calibration-constrained analysis

NASA Astrophysics Data System (ADS)

Harp, D. R.; Atchley, A. L.; Painter, S. L.; Coon, E. T.; Wilson, C. J.; Romanovsky, V. E.; Rowland, J. C.

2016-02-01

The effects of soil property uncertainties on permafrost thaw projections are studied using a three-phase subsurface thermal hydrology model and calibration-constrained uncertainty analysis. The null-space Monte Carlo method is used to identify soil hydrothermal parameter combinations that are consistent with borehole temperature measurements at the study site, the Barrow Environmental Observatory. Each parameter combination is then used in a forward projection of permafrost conditions for the 21st century (from calendar year 2006 to 2100) using atmospheric forcings from the Community Earth System Model (CESM) in the Representative Concentration Pathway (RCP) 8.5 greenhouse gas concentration trajectory. A 100-year projection allows for the evaluation of predictive uncertainty (due to soil property (parametric) uncertainty) and the inter-annual climate variability due to year to year differences in CESM climate forcings. After calibrating to measured borehole temperature data at this well-characterized site, soil property uncertainties are still significant and result in significant predictive uncertainties in projected active layer thickness and annual thaw depth-duration even with a specified future climate. Inter-annual climate variability in projected soil moisture content and Stefan number are small. A volume- and time-integrated Stefan number decreases significantly, indicating a shift in subsurface energy utilization in the future climate (latent heat of phase change becomes more important than heat conduction). Out of 10 soil parameters, ALT, annual thaw depth-duration, and Stefan number are highly dependent on mineral soil porosity, while annual mean liquid saturation of the active layer is highly dependent on the mineral soil residual saturation and moderately dependent on peat residual saturation. By comparing the ensemble statistics to the spread of projected permafrost metrics using different climate models, we quantify the relative magnitude of soil property uncertainty to another source of permafrost uncertainty, structural climate model uncertainty. We show that the effect of calibration-constrained uncertainty in soil properties, although significant, is less than that produced by structural climate model uncertainty for this location.

Upper ocean climate of the Eastern Mediterranean Sea during the Holocene Insolation Maximum - a model study

NASA Astrophysics Data System (ADS)

Adloff, F.; Mikolajewicz, U.; Kučera, M.; Grimm, R.; Maier-Reimer, E.; Schmiedl, G.; Emeis, K.-C.

2011-10-01

Nine thousand years ago (9 ka BP), the Northern Hemisphere experienced enhanced seasonality caused by an orbital configuration close to the minimum of the precession index. To assess the impact of this "Holocene Insolation Maximum" (HIM) on the Mediterranean Sea, we use a regional ocean general circulation model forced by atmospheric input derived from global simulations. A stronger seasonal cycle is simulated by the model, which shows a relatively homogeneous winter cooling and a summer warming with well-defined spatial patterns, in particular, a subsurface warming in the Cretan and western Levantine areas. The comparison between the SST simulated for the HIM and a reconstruction from planktonic foraminifera transfer functions shows a poor agreement, especially for summer, when the vertical temperature gradient is strong. As a novel approach, we propose a reinterpretation of the reconstruction, to consider the conditions throughout the upper water column rather than at a single depth. We claim that such a depth-integrated approach is more adequate for surface temperature comparison purposes in a situation where the upper ocean structure in the past was different from the present-day. In this case, the depth-integrated interpretation of the proxy data strongly improves the agreement between modelled and reconstructed temperature signal with the subsurface summer warming being recorded by both model and proxies, with a small shift to the south in the model results. The mechanisms responsible for the peculiar subsurface pattern are found to be a combination of enhanced downwelling and wind mixing due to strengthened Etesian winds, and enhanced thermal forcing due to the stronger summer insolation in the Northern Hemisphere. Together, these processes induce a stronger heat transfer from the surface to the subsurface during late summer in the western Levantine; this leads to an enhanced heat piracy in this region, a process never identified before, but potentially characteristic of time slices with enhanced insolation.

Corrigendum to "Upper ocean climate of the Eastern Mediterranean Sea during the Holocene Insolation Maximum - a model study" published in Clim. Past, 7, 1103-1122, 2011

NASA Astrophysics Data System (ADS)

Adloff, F.; Mikolajewicz, U.; Kučera, M.; Grimm, R.; Maier-Reimer, E.; Schmiedl, G.; Emeis, K.-C.

2011-11-01

Nine thousand years ago (9 ka BP), the Northern Hemisphere experienced enhanced seasonality caused by an orbital configuration close to the minimum of the precession index. To assess the impact of this "Holocene Insolation Maximum" (HIM) on the Mediterranean Sea, we use a regional ocean general circulation model forced by atmospheric input derived from global simulations. A stronger seasonal cycle is simulated by the model, which shows a relatively homogeneous winter cooling and a summer warming with well-defined spatial patterns, in particular, a subsurface warming in the Cretan and western Levantine areas. The comparison between the SST simulated for the HIM and a reconstruction from planktonic foraminifera transfer functions shows a poor agreement, especially for summer, when the vertical temperature gradient is strong. As a novel approach, we propose a reinterpretation of the reconstruction, to consider the conditions throughout the upper water column rather than at a single depth. We claim that such a depth-integrated approach is more adequate for surface temperature comparison purposes in a situation where the upper ocean structure in the past was different from the present-day. In this case, the depth-integrated interpretation of the proxy data strongly improves the agreement between modelled and reconstructed temperature signal with the subsurface summer warming being recorded by both model and proxies, with a small shift to the south in the model results. The mechanisms responsible for the peculiar subsurface pattern are found to be a combination of enhanced downwelling and wind mixing due to strengthened Etesian winds, and enhanced thermal forcing due to the stronger summer insolation in the Northern Hemisphere. Together, these processes induce a stronger heat transfer from the surface to the subsurface during late summer in the western Levantine; this leads to an enhanced heat piracy in this region, a process never identified before, but potentially characteristic of time slices with enhanced insolation.

Methods for Aquifer Thermal Energy Storage planning; The hidden side of cities.

NASA Astrophysics Data System (ADS)

Jaxa-Rozen, M.; Bloemendal, M.; Theo, O.

2017-12-01

Aquifer Thermal Energy Storage (ATES) systems reduce energy use and greenhouse gas emissions in urban areas, by supplying heating and cooling to buildings with a heat pump combined with seasonal heat storage in aquifers. The climactic and geohydrological conditions required for this technology can be found in many temperate regions around the world; In The Netherlands there are currently approximately 2,200 active systems. Despite this modest adoption level, many urban areas in the Netherlands already struggle to accommodate the subsurface claims needed to further develop ATES under current planning regulations. To identify best practices for ATES planning and maximize the technology's future potential, this work first reviews a set of 24 ATES-plans which were used for the spatial layout of ATES in various urban areas in The Netherlands and the method used to make those plans. This analysis revealed that three crucial elements are found to be missing in current ATES planning: i) a consistent assessment framework which can be used to compare the performance of different planning strategies; ii) a systematic adjustment of ATES design parameters to suit local conditions; iii) the identification and use of aquifer allocation thresholds to guide the choice of a planning strategy. All three steps are elaborated and added to the method. For the latter, these thresholds are identified by exploratory numerical modelling, using a coupled agent-based/geohydrological (MODFLOW) simulation to explore a broad range of scenarios for ATES design and layout parameters. The results give insight in how technical ATES-well design choices affect optimal use of subsurface space and in the trade-of between individual efficiency and overall emission reductions. The improved ATES-planning method now fosters planning and design rules ensuring optimal and sustainable use of subsurface space, i.e. maximizing energy saving by accommodating as much ATES systems as possible while maintaining individual well efficiency.

PFLOTRAN-E4D: A parallel open source PFLOTRAN module for simulating time-lapse electrical resistivity data

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

Johnson, Timothy C.; Hammond, Glenn E.; Chen, Xingyuan

Time-lapse electrical resistivity tomography (ERT) is finding increased application for remotely monitoring processes occurring in the near subsurface in three-dimensions (i.e. 4D monitoring). However, there are few codes capable of simulating the evolution of subsurface resistivity and corresponding tomographic measurements arising from a particular process, particularly in parallel and with an open source license. Herein we describe and demonstrate an electrical resistivity tomography module for the PFLOTRAN subsurface simulation code, named PFLOTRAN-E4D. The PFLOTRAN-E4D module operates in parallel using a dedicated set of compute cores in a master-slave configuration. At each time step, the master processes receives subsurface states frommore » PFLOTRAN, converts those states to bulk electrical conductivity, and instructs the slave processes to simulate a tomographic data set. The resulting multi-physics simulation capability enables accurate feasibility studies for ERT imaging, the identification of the ERT signatures that are unique to a given process, and facilitates the joint inversion of ERT data with hydrogeological data for subsurface characterization. PFLOTRAN-E4D is demonstrated herein using a field study of stage-driven groundwater/river water interaction ERT monitoring along the Columbia River, Washington, USA. Results demonstrate the complex nature of changes subsurface electrical conductivity, in both the saturated and unsaturated zones, arising from water table changes and from river water intrusion into the aquifer. The results also demonstrate the sensitivity of surface based ERT measurements to those changes over time. PFLOTRAN-E4D is available with the PFLOTRAN development version with an open-source license at https://bitbucket.org/pflotran/pflotran-dev .« less

PFLOTRAN-E4D: A parallel open source PFLOTRAN module for simulating time-lapse electrical resistivity data

NASA Astrophysics Data System (ADS)

Johnson, Timothy C.; Hammond, Glenn E.; Chen, Xingyuan

2017-02-01

Time-lapse electrical resistivity tomography (ERT) is finding increased application for remotely monitoring processes occurring in the near subsurface in three-dimensions (i.e. 4D monitoring). However, there are few codes capable of simulating the evolution of subsurface resistivity and corresponding tomographic measurements arising from a particular process, particularly in parallel and with an open source license. Herein we describe and demonstrate an electrical resistivity tomography module for the PFLOTRAN subsurface flow and reactive transport simulation code, named PFLOTRAN-E4D. The PFLOTRAN-E4D module operates in parallel using a dedicated set of compute cores in a master-slave configuration. At each time step, the master processes receives subsurface states from PFLOTRAN, converts those states to bulk electrical conductivity, and instructs the slave processes to simulate a tomographic data set. The resulting multi-physics simulation capability enables accurate feasibility studies for ERT imaging, the identification of the ERT signatures that are unique to a given process, and facilitates the joint inversion of ERT data with hydrogeological data for subsurface characterization. PFLOTRAN-E4D is demonstrated herein using a field study of stage-driven groundwater/river water interaction ERT monitoring along the Columbia River, Washington, USA. Results demonstrate the complex nature of subsurface electrical conductivity changes, in both the saturated and unsaturated zones, arising from river stage fluctuations and associated river water intrusion into the aquifer. The results also demonstrate the sensitivity of surface based ERT measurements to those changes over time. PFLOTRAN-E4D is available with the PFLOTRAN development version with an open-source license at https://bitbucket.org/pflotran/pflotran-dev.

Improved Geologic Interpretation of Non-invasive Electrical Resistivity Imaging from In-situ Samples

NASA Astrophysics Data System (ADS)

Mucelli, A.; Aborn, L.; Jacob, R.; Malusis, M.; Evans, J.

2016-12-01

Non-invasive geophysical techniques are useful in characterizing the subsurface geology without disturbing the environment, however, the ability to interpret the subsurface is enhanced by invasive work. Since geologic materials have electrical resistivity values it allows for a geologic interpretation to be made based on variations of electrical resistivity measured by electrical resistivity imaging (ERI). This study focuses on the pre-characterization of the geologic subsurface from ERI collected adjacent to the Montandon Marsh, a wetland located near Lewisburg, PA within the West Branch of the Susquehanna River watershed. The previous invasive data, boreholes, indicate that the subsurface consists of limestone and shale bedrock overlain with sand and gravel deposits from glacial outwash and aeolian processes. The objective is to improve our understanding of the subsurface at this long-term hydrologic research site by using excavation results, specifically observed variations in geologic materials and electrical resistivity laboratory testing of subsurface samples. The pre-excavation ERI indicated that the shallow-most geologic material had a resistivity value of 100-500 ohm-m. In comparison, the laboratory testing indicated the shallow-most material had the same range of electrical resistivity values depending on saturation levels. The ERI also showed that there was an electrically conductive material, 7 to 70 ohm-m, that was interpreted to be clay and agreed with borehole data, however, the excavation revealed that at this depth range the geologic material varied from stratified clay to clay with cobbles to weathered residual clay. Excavation revealed that the subtle variations in the electrical conductive material corresponded well with the variations in the geologic material. We will use these results to reinterpret previously collected ERI data from the entire long-term research site.

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

PubMed

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

2011-01-01

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

Ground-water heat pumps: An examination of hydrogeologic, environmental, legal, and economic factors affecting their use. Volume 1: Main text, appendices A, B, and C

NASA Astrophysics Data System (ADS)

Armitage, D. M.; Bacon, D. J.; Massey-Norton, J. T.; Miller, J. M.

1980-11-01

Groundwater is attractive as a potential low temperature energy source in residential space conditioning applications. When used in conjunction with a heat pump, ground water can serve as both a heat source and a heat sink. Major hydrogeologic aspects that affect system use include groundwater temperature and availability at shallow depths as these factors influence operational efficiency. Ground water quality is considered as it affects the performance and life expectancy of the water side heat exchanger. Environmental impacts related to groundwater heat pump system use are most influenced by water use and disposal methods. In general, recharge to the subsurface is recommended. Legal restrictions on system use are often stricter at the municipal and county levels than at state and federal levels. Computer simulations indicate that under a variety of climatologic conditions, groundwater heat pumps use less energy than conventional heating and cooling equipment. Life cycle cost comparisons with conventional equipment depend on alternative system choices and well cost options included in the groundwater heat pump system.

Detection in subsurface air of radioxenon released from medical isotope production

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

Johnson, Christine; Biegalski, Steven; Haas, Derek

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

Corn stover harvest increases herbicide movement to subsurface drains - Root Zone Water Quality Model simulations.

PubMed

Shipitalo, Martin J; Malone, Robert W; Ma, Liwang; Nolan, Bernard T; Kanwar, Rameshwar S; Shaner, Dale L; Pederson, Carl H

2016-06-01

Crop residue removal for bioenergy production can alter soil hydrologic properties and the movement of agrochemicals to subsurface drains. The Root Zone Water Quality Model (RZWQM), previously calibrated using measured flow and atrazine concentrations in drainage from a 0.4 ha chisel-tilled plot, was used to investigate effects of 50 and 100% corn (Zea mays L.) stover harvest and the accompanying reductions in soil crust hydraulic conductivity and total macroporosity on transport of atrazine, metolachlor and metolachlor oxanilic acid (OXA). The model accurately simulated field-measured metolachlor transport in drainage. A 3 year simulation indicated that 50% residue removal reduced subsurface drainage by 31% and increased atrazine and metolachlor transport in drainage 4-5-fold when surface crust conductivity and macroporosity were reduced by 25%. Based on its measured sorption coefficient, approximately twofold reductions in OXA losses were simulated with residue removal. The RZWQM indicated that, if corn stover harvest reduces crust conductivity and soil macroporosity, losses of atrazine and metolachlor in subsurface drainage will increase owing to reduced sorption related to more water moving through fewer macropores. Losses of the metolachlor degradation product OXA will decrease as a result of the more rapid movement of the parent compound into the soil. Published 2015. This article is a U.S. Government work and is in the public domain in the USA. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

LOCATION AND CHARACTERIZATION OF SUBSURFACE ANOMALIES USING A SOIL CONDUCTIVITY PROBE

EPA Science Inventory

An electrical conductivity probe, designed for use with "direct push" technology, has been successfully used to locate buried drums, contaminant plumes, and to precisely locate and characterize a previously installed permeable reactive iron wall. The conductivity probe was desig...

Effects of rainfall patterns and land cover on the subsurface flow generation of sloping Ferralsols in southern China

PubMed Central

Yang, Jie; Tang, Chongjun; Chen, Lihua; Liu, Yaojun; Wang, Lingyun

2017-01-01

Rainfall patterns and land cover are two important factors that affect the runoff generation process. To determine the surface and subsurface flows associated with different rainfall patterns on sloping Ferralsols under different land cover types, observational data related to surface and subsurface flows from 5 m × 15 m plots were collected from 2010 to 2012. The experiment was conducted to assess three land cover types (grass, litter cover and bare land) in the Jiangxi Provincial Soil and Water Conservation Ecological Park. During the study period, 114 natural rainfall events produced subsurface flow and were divided into four groups using k-means clustering according to rainfall duration, rainfall depth and maximum 30-min rainfall intensity. The results showed that the total runoff and surface flow values were highest for bare land under all four rainfall patterns and lowest for the covered plots. However, covered plots generated higher subsurface flow values than bare land. Moreover, the surface and subsurface flows associated with the three land cover types differed significantly under different rainfall patterns. Rainfall patterns with low intensities and long durations created more subsurface flow in the grass and litter cover types, whereas rainfall patterns with high intensities and short durations resulted in greater surface flow over bare land. Rainfall pattern I had the highest surface and subsurface flow values for the grass cover and litter cover types. The highest surface flow value and lowest subsurface flow value for bare land occurred under rainfall pattern IV. Rainfall pattern II generated the highest subsurface flow value for bare land. Therefore, grass or litter cover are able to convert more surface flow into subsurface flow under different rainfall patterns. The rainfall patterns studied had greater effects on subsurface flow than on total runoff and surface flow for covered surfaces, as well as a greater effect on surface flows associated with bare land. PMID:28792507

Integrated geophysical investigations for the delineation of source and subsurface structure associated with hydro-uranium anomaly: A case study from South Purulia Shear Zone (SPSZ), India

NASA Astrophysics Data System (ADS)

Sharma, S. P.; Biswas, A.

2012-12-01

South Purulia Shear Zone (SPSZ) is an important region for prospecting of uranium mineralization. Geological studies and hydro-uranium anomaly suggest the presence of Uranium deposit around Raghunathpur village which lies about 8 km north of SPSZ. However, detailed geophysical investigations have not been carried out in this region for investigation of uranium mineralization. Since surface signature of uranium mineralization is not depicted near the location, a deeper subsurface source is expected for hydro uranium anomaly. To delineate the subsurface structure and to investigate the origin of hydro-uranium anomaly present in the area, Vertical Electrical Sounding (VES) using Schlumberger array and Gradient Resistivity Profiling (GRP) were performed at different locations along a profile perpendicular to the South Purulia Shear Zone. Apparent resistivity computed from the measured sounding data at various locations shows a continuously increasing trend. As a result, conventional apparent resistivity data is not able to detect the possible source of hydro uranium anomaly. An innovative approach is applied which depicts the apparent conductivity in the subsurface revealed a possible connection from SPSZ to Raghunathpur. On the other hand resistivity profiling data suggests a low resistive zone which is also characterized by low Self-Potential (SP) anomaly zone. Since SPSZ is characterized by the source of uranium mineralization; hydro-uranium anomaly at Raghunathpur is connected with the SPSZ. The conducting zone has been delineated from SPSZ to Raghunathpur at deeper depths which could be uranium bearing. Since the location is also characterized by a low gravity and high magnetic anomaly zone, this conducting zone is likely to be mineralized zone. Keywords: Apparent resistivity; apparent conductivity; Self Potential; Uranium mineralization; shear zone; hydro-uranium anomaly.

3D slicing of radiogenic heat production in Bahariya Formation, Tut oil field, North-Western Desert, Egypt.

PubMed

Al-Alfy, I M; Nabih, M A

2013-03-01

A 3D block of radiogenic heat production was constructed from the subsurface total gamma ray logs of Bahariya Formation, Western Desert, Egypt. The studied rocks possess a range of radiogenic heat production varying from 0.21 μWm(-3) to 2.2 μWm(-3). Sandstone rocks of Bahariya Formation have higher radiogenic heat production than the average for crustal sedimentary rocks. The high values of density log of Bahariya Formation indicate the presence of iron oxides which contribute the uranium radioactive ores that increase the radiogenic heat production of these rocks. The average radiogenic heat production produced from the study area is calculated as 6.3 kW. The histogram and cumulative frequency analyses illustrate that the range from 0.8 to 1.2 μWm(-3) is about 45.3% of radiogenic heat production values. The 3D slicing of the reservoir shows that the southeastern and northeastern parts of the study area have higher radiogenic heat production than other parts. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

Catchment Tomography - Joint Estimation of Surface Roughness and Hydraulic Conductivity with the EnKF

NASA Astrophysics Data System (ADS)

Baatz, D.; Kurtz, W.; Hendricks Franssen, H. J.; Vereecken, H.; Kollet, S. J.

2017-12-01

Parameter estimation for physically based, distributed hydrological models becomes increasingly challenging with increasing model complexity. The number of parameters is usually large and the number of observations relatively small, which results in large uncertainties. A moving transmitter - receiver concept to estimate spatially distributed hydrological parameters is presented by catchment tomography. In this concept, precipitation, highly variable in time and space, serves as a moving transmitter. As response to precipitation, runoff and stream discharge are generated along different paths and time scales, depending on surface and subsurface flow properties. Stream water levels are thus an integrated signal of upstream parameters, measured by stream gauges which serve as the receivers. These stream water level observations are assimilated into a distributed hydrological model, which is forced with high resolution, radar based precipitation estimates. Applying a joint state-parameter update with the Ensemble Kalman Filter, the spatially distributed Manning's roughness coefficient and saturated hydraulic conductivity are estimated jointly. The sequential data assimilation continuously integrates new information into the parameter estimation problem, especially during precipitation events. Every precipitation event constrains the possible parameter space. In the approach, forward simulations are performed with ParFlow, a variable saturated subsurface and overland flow model. ParFlow is coupled to the Parallel Data Assimilation Framework for the data assimilation and the joint state-parameter update. In synthetic, 3-dimensional experiments including surface and subsurface flow, hydraulic conductivity and the Manning's coefficient are efficiently estimated with the catchment tomography approach. A joint update of the Manning's coefficient and hydraulic conductivity tends to improve the parameter estimation compared to a single parameter update, especially in cases of biased initial parameter ensembles. The computational experiments additionally show to which degree of spatial heterogeneity and to which degree of uncertainty of subsurface flow parameters the Manning's coefficient and hydraulic conductivity can be estimated efficiently.

Thermal treatment of low permeability soils using electrical resistance heating

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

Udell, K.S.

1996-08-01

The acceleration of recovery rates of second phase liquid contaminants from the subsurface during gas or water pumping operations is realized by increasing the soil and ground water temperature. Electrical heating with AC current is one method of increasing the soil and groundwater temperature and has particular applicability to low permeability soils. Several mechanisms have been identified that account for the enhanced removal of the contaminants during electrical heating. These are vaporization of liquid contaminants with low boiling points, temperature-enhanced evaporation rates of semi-volatile components, and removal of residual contaminants by the boiling of residual water. Field scale studies ofmore » electrical heating and fluid extraction show the effectiveness of this technique and its applicability to contaminants found both above and below the water table and within low permeability soils. 10 refs., 8 figs.« less

Hydrology and numerical simulation of groundwater movement and heat transport in Snake Valley and surrounding areas, Juab, Miller, and Beaver Counties, Utah, and White Pine and Lincoln Counties, Nevada

USGS Publications Warehouse

Masbruch, Melissa D.; Gardner, Philip M.; Brooks, Lynette E.

2014-01-01

Snake Valley and surrounding areas, along the Utah-Nevada state border, are part of the Great Basin carbonate and alluvial aquifer system. The groundwater system in the study area consists of water in unconsolidated deposits in basins and water in consolidated rock underlying the basins and in the adjacent mountain blocks. Most recharge occurs from precipitation on the mountain blocks and most discharge occurs from the lower altitude basin-fill deposits mainly as evapotranspiration, springflow, and well withdrawals.The Snake Valley area regional groundwater system was simulated using a three-dimensional model incorporating both groundwater flow and heat transport. The model was constructed with MODFLOW-2000, a version of the U.S. Geological Survey’s groundwater flow model, and MT3DMS, a transport model that simulates advection, dispersion, and chemical reactions of solutes or heat in groundwater systems. Observations of groundwater discharge by evapotranspiration, springflow, mountain stream base flow, and well withdrawals; groundwater-level altitudes; and groundwater temperatures were used to calibrate the model. Parameter values estimated by regression analyses were reasonable and within the range of expected values.This study represents one of the first regional modeling efforts to include calibration to groundwater temperature data. The inclusion of temperature observations reduced parameter uncertainty, in some cases quite significantly, over using just water-level altitude and discharge observations. Of the 39 parameters used to simulate horizontal hydraulic conductivity, uncertainty on 11 of these parameters was reduced to one order of magnitude or less. Other significant reductions in parameter uncertainty occurred in parameters representing the vertical anisotropy ratio, drain and river conductance, recharge rates, and well withdrawal rates.The model provides a good representation of the groundwater system. Simulated water-level altitudes range over almost 2,000 meters (m); 98 percent of the simulated values of water-level altitudes in wells are within 30 m of observed water-level altitudes, and 58 percent of them are within 12 m. Nineteen of 20 simulated discharges are within 30 percent of observed discharge. Eighty-one percent of the simulated values of groundwater temperatures in wells are within 2 degrees Celsius (°C) of the observed values, and 55 percent of them are within 0.75 °C. The numerical model represents a more robust quantification of groundwater budget components than previous studies because the model integrates all components of the groundwater budget. The model also incorporates new data including (1) a detailed hydrogeologic framework, and (2) more observations, including several new water-level altitudes throughout the study area, several new measurements of spring discharge within Snake Valley which had not previously been monitored, and groundwater temperature data. Uncertainty in the estimates of subsurface flow are less than those of previous studies because the model balanced recharge and discharge across the entire simulated area, not just in each hydrographic area, and because of the large dataset of observations (water-level altitudes, discharge, and temperatures) used to calibrate the model and the resulting transmissivity distribution.Groundwater recharge from precipitation and unconsumed irrigation in Snake Valley is 160,000 acre-feet per year (acre-ft/yr), which is within the range of previous estimates. Subsurface inflow from southern Spring Valley to southern Snake Valley is 13,000 acre-ft/yr and is within the range of previous estimates; subsurface inflow from Spring Valley to Snake Valley north of the Snake Range, however, is only 2,200 acre-ft/yr, which is much less than has been previously estimated. Groundwater discharge from groundwater evapotranspiration and springs is 100,000 acre-ft/yr, and discharge to mountain streams is 3,300 acre-ft/yr; these are within the range of previous estimates. Current well withdrawals are 28,000 acre-ft/yr. Subsurface outflow from Snake Valley moves into Pine Valley (2,000 acre-ft/yr), Wah Wah Valley (23 acre-ft/yr), Tule Valley (33,000 acre-ft/yr), Fish Springs Flat (790 acre-ft/yr), and outside of the study area towards Great Salt Lake Desert (8,400 acre-ft/yr); these outflows, totaling about 44,000 acre-ft/yr, are within the range of previous estimates.The subsurface flow amounts indicate the degree of connectivity between hydrographic areas within the study area. The simulated transmissivity and locations of natural discharge, however, provide a better estimate of the effect of groundwater withdrawals on groundwater resources than does the amount and direction of subsurface flow between hydrographic areas. The distribution of simulated transmissivity throughout the study area includes many areas of high transmissivity within and between hydrographic areas. Increased well withdrawals within these high transmissivity areas will likely affect a large part of the study area, resulting in declining groundwater levels, as well as leading to a decrease in natural discharge to springs and evapotranspiration.

Influence of root-water-uptake parameterization on simulated heat transport in a structured forest soil

NASA Astrophysics Data System (ADS)

Votrubova, Jana; Vogel, Tomas; Dohnal, Michal; Dusek, Jaromir

2015-04-01

Coupled simulations of soil water flow and associated transport of substances have become a useful and increasingly popular tool of subsurface hydrology. Quality of such simulations is directly affected by correctness of its hydraulic part. When near-surface processes under vegetation cover are of interest, appropriate representation of the root water uptake becomes essential. Simulation study of coupled water and heat transport in soil profile under natural conditions was conducted. One-dimensional dual-continuum model (S1D code) with semi-separate flow domains representing the soil matrix and the network of preferential pathways was used. A simple root water uptake model based on water-potential-gradient (WPG) formulation was applied. As demonstrated before [1], the WPG formulation - capable of simulating both the compensatory root water uptake (in situations when reduced uptake from dry layers is compensated by increased uptake from wetter layers), and the root-mediated hydraulic redistribution of soil water - enables simulation of more natural soil moisture distribution throughout the root zone. The potential effect on heat transport in a soil profile is the subject of the present study. [1] Vogel T., M. Dohnal, J. Dusek, J. Votrubova, and M. Tesar. 2013. Macroscopic modeling of plant water uptake in a forest stand involving root-mediated soil-water redistribution. Vadose Zone Journal, 12, 10.2136/vzj2012.0154. The research was supported by the Czech Science Foundation Project No. 14-15201J.

Analysis of Geothermal Pathway in the Metamorphic Area, Northeastern Taiwan

NASA Astrophysics Data System (ADS)

Wang, C.; Wu, M. Y.; Song, S. R.; Lo, W.

2016-12-01

A quantitative measure by play fairway analysis in geothermal energy development is an important tool that can present the probability map of potential resources through the uncertainty studies in geology for early phase decision making purpose in the related industries. While source, pathway, and fluid are the three main geologic factors in traditional geothermal systems, identifying the heat paths is critical to reduce drilling cost. Taiwan is in East Asia and the western edge of Pacific Ocean, locating on the convergent boundary of Eurasian Plate and Philippine Sea Plate with many earthquake activities. This study chooses a metamorphic area in the western corner of Yi-Lan plain in northeastern Taiwan with high geothermal potential and several existing exploration sites. Having high subsurface temperature gradient from the mountain belts, and plenty hydrologic systems through thousands of millimeters annual precipitation that would bring up heats closer to the surface, current geothermal conceptual model indicates the importance of pathway distribution which affects the possible concentration of extractable heat location. The study conducts surface lineation analysis using analytic hierarchy process to determine weights among various fracture types for their roles in geothermal pathways, based on the information of remote sensing data, published geologic maps and field work measurements, to produce regional fracture distribution probability map. The results display how the spatial distribution of pathways through various fractures could affect geothermal systems, identify the geothermal plays using statistical data analysis, and compare against the existing drilling data.

In situ oxidation of subsurface formations

DOEpatents

Beer, Gary Lee [Houston, TX; Mo, Weijian [Sugar Land, TX; Li, Busheng [Houston, TX; Shen, Chonghui [Calgary, CA

2011-01-11

Methods and systems for treating a hydrocarbon containing formation described herein include providing heat to a first portion of the formation from a plurality of heaters in the first portion, producing produced through one or more production wells in a second portion of the formation, reducing or turning off heat provided to the first portion after a selected time, providing an oxidizing fluid through one or more of the heater wells in the first portion, providing heat to the first portion and the second portion through oxidation of at least some hydrocarbons in the first portion, and producing fluids through at least one of the production wells in the second portion. The produced fluids may include at least some oxidized hydrocarbons produced in the first portion.

Methods of producing alkylated hydrocarbons from an in situ heat treatment process liquid

DOEpatents

Roes, Augustinus Wilhelmus Maria [Houston, TX; Mo, Weijian [Sugar Land, TX; Muylle, Michel Serge Marie [Houston, TX; Mandema, Remco Hugo [Houston, TX; Nair, Vijay [Katy, TX

2009-09-01

A method for producing alkylated hydrocarbons is disclosed. Formation fluid is produced from a subsurface in situ heat treatment process. The formation fluid is separated to produce a liquid stream and a first gas stream. The first gas stream includes olefins. The liquid stream is fractionated to produce at least a second gas stream including hydrocarbons having a carbon number of at least 3. The first gas stream and the second gas stream are introduced into an alkylation unit to produce alkylated hydrocarbons. At least a portion of the olefins in the first gas stream enhance alkylation.

The geothermal energy potential in Denmark - updating the database and new structural and thermal models

NASA Astrophysics Data System (ADS)

Nielsen, Lars Henrik; Sparre Andersen, Morten; Balling, Niels; Boldreel, Lars Ole; Fuchs, Sven; Leth Hjuler, Morten; Kristensen, Lars; Mathiesen, Anders; Olivarius, Mette; Weibel, Rikke

2017-04-01

Knowledge of structural, hydraulic and thermal conditions of the subsurface is fundamental for the planning and use of hydrothermal energy. In the framework of a project under the Danish Research program 'Sustainable Energy and Environment' funded by the 'Danish Agency for Science, Technology and Innovation', fundamental geological and geophysical information of importance for the utilization of geothermal energy in Denmark was compiled, analyzed and re-interpreted. A 3D geological model was constructed and used as structural basis for the development of a national subsurface temperature model. In that frame, all available reflection seismic data were interpreted, quality controlled and integrated to improve the regional structural understanding. The analyses and interpretation of available relevant data (i.e. old and new seismic profiles, core and well-log data, literature data) and a new time-depth conversion allowed a consistent correlation of seismic surfaces for whole Denmark and across tectonic features. On this basis, new topologically consistent depth and thickness maps for 16 geological units from the top pre-Zechstein to the surface were drawn. A new 3D structural geological model was developed with special emphasis on potential geothermal reservoirs. The interpretation of petrophysical data (core data and well-logs) allows to evaluate the hydraulic and thermal properties of potential geothermal reservoirs and to develop a parameterized numerical 3D conductive subsurface temperature model. Reservoir properties and quality were estimated by integrating petrography and diagenesis studies with porosity-permeability data. Detailed interpretation of the reservoir quality of the geological formations was made by estimating net reservoir sandstone thickness based on well-log analysis, determination of mineralogy including sediment provenance analysis, and burial history data. New local surface heat-flow values (range: 64-84 mW/m2) were determined for the Danish Basin and predicted temperatures were calibrated and validated by borehole temperature observations. Finally, new temperature maps for major geological reservoir formations (Frederikshavn, Haldager Sand, Gassum and Bunter Sandstone/Skagerrak formations) and selected constant depth intervals (1 km, 2 km, etc.) were compiled. In the future, geothermal energy is likely to be a key component in Denmark's supply of energy and integrated into the district heating infrastructures. A new 3-year project (GEOTHERM) under the Innovation Fund Denmark will focus on addressing and removing remaining geological, technical and commercial obstacles. The presented 3D geothermal model will be an important component in more precise assessments of the geothermal resource, production capacity and thermal lifecycle.

Planetary Ice-Oceans: Numerical Modeling Study of Ice-Shell Growth in Convecting Two-Phase Systems

NASA Astrophysics Data System (ADS)

Allu Peddinti, Divya; McNamara, Allen

2017-04-01

Several icy bodies in the Solar system such as the icy moons Europa and Enceladus exhibit signs of subsurface oceans underneath an ice-shell. For Europa, the geologically young surface, the presence of surface features and the aligned surface chemistry pose interesting questions about formation of the ice-shell and its interaction with the ocean below. This also ties in with its astrobiological potential and implications for similar ice-ocean systems elsewhere in the cosmos. The overall thickness of the H2O layer on Europa is estimated to be 100-150 km while the thickness of the ice-shell is debated. Additionally, Europa is subject to tidal heating due to interaction with Jupiter's immense gravity field. It is of interest to understand how the ice-shell thickness varies in the presence of tidal internal heating and the localization of heating in different regions of the ice-shell. Thus this study aims to determine the effect of tidal internal heating on the growth rate of the ice-shell over time. We perform geodynamic modeling of the ice-ocean system in order to understand how the ice-shell thickness changes with time. The convection code employs the ice Ih-water phase diagram in order to model the two-phase convecting ice-ocean system. All the models begin from an initial warm thick ocean that cools from the top. The numerical experiments analyze three cases: case 1 with no tidal internal heating in the system, case 2 with constant tidal internal heating in the ice and case 3 with viscosity-dependent tidal internal heating in the ice. We track the ice-shell thickness as a function of time as the system cools. Modeling results so far have identified that the shell growth rate changes substantially at a point in time that coincides with a change in the planform of ice-convection cells. Additionally, the velocity vs depth plots indicate a shift from a conduction dominant to a convection dominant ice regime. We compare the three different cases to provide a comprehensive understanding of the temporal variation in the ice-shell thickness due to the addition of heating in the ice.

On the effects of subsurface parameters on evaporite dissolution (Switzerland)

NASA Astrophysics Data System (ADS)

Zidane, Ali; Zechner, Eric; Huggenberger, Peter; Younes, Anis

2014-05-01

Uncontrolled subsurface evaporite dissolution could lead to hazards such as land subsidence. Observed subsidences in a study area of Northwestern Switzerland were mainly due to subsurface dissolution (subrosion) of evaporites such as halite and gypsum. A set of 2D density driven flow simulations were evaluated along 1000 m long and 150 m deep 2D cross sections within the study area that is characterized by tectonic horst and graben structures. The simulations were conducted to study the effect of the different subsurface parameters that could affect the dissolution process. The heterogeneity of normal faults and its impact on the dissolution of evaporites is studied by considering several permeable faults that include non-permeable areas. The mixed finite element method (MFE) is used to solve the flow equation, coupled with the multipoint flux approximation (MPFA) and the discontinuous Galerkin method (DG) to solve the diffusion and the advection parts of the transport equation.

An open-loop ground-water heat pump system: transient numerical modeling and site experimental results

NASA Astrophysics Data System (ADS)

Lo Russo, S.; Taddia, G.; Gnavi, L.

2012-04-01

KEY WORDS: Open-loop ground water heat pump; Feflow; Low-enthalpy; Thermal Affected Zone; Turin; Italy The increasing diffusion of low-enthalpy geothermal open-loop Groundwater Heat Pumps (GWHP) providing buildings air conditioning requires a careful assessment of the overall effects on groundwater system, especially in the urban areas where several plants can be close together and interfere. One of the fundamental aspects in the realization of an open loop low-enthalpy geothermal system is therefore the capacity to forecast the effects of thermal alteration produced in the ground, induced by the geothermal system itself. The impact on the groundwater temperature in the surrounding area of the re-injection well (Thermal Affected Zone - TAZ) is directly linked to the aquifer properties. The transient dynamic of groundwater discharge and temperature variations should be also considered to assess the subsurface environmental effects of the plant. The experimental groundwater heat pump system used in this study is installed at the "Politecnico di Torino" (NW Italy, Piedmont Region). This plant provides summer cooling needs for the university buildings. This system is composed by a pumping well, a downgradient injection well and a control piezometer. The system is constantly monitored by multiparameter probes measuring the dynamic of groundwater temperature. A finite element subsurface flow and transport simulator (FEFLOW) was used to investigate the thermal aquifer alteration. Simulations were continuously performed during May-October 2010 (cooling period). The numerical simulation of the heat transport in the aquifer was solved with transient conditions. The simulation was performed by considering only the heat transfer within the saturated aquifer, without any heat dispersion above or below the saturated zone due to the lack of detailed information regarding the unsaturated zone. Model results were compared with experimental temperature data derived from groundwater monitoring in the surrounding area of the injection well. Such analysis showed that the measured values differ slightly from the simulated values. That small difference is probably due to the simplification assumptions in the modelling. This hypothesis is still under investigation.

Atmospheres

NASA Astrophysics Data System (ADS)

Bott, June; Yin, Hongbin; Sridhar, Seetharaman

2014-12-01

When high Al containing Fe alloys such as TRIP steels are exposed to atmospheres that contain N2 during re-heating, sub-surface nitrides form and these can be detrimental to mechanical properties. Nitride precipitation can be controlled by minimizing the access of the gaseous atmosphere to the metal surface, which can be achieved by a rapid growth of a continuous and adherent surface scale. This investigation utilizes a Au-image furnace attached to a confocal scanning microscope to simulate the annealing temperature vs time while Fe-Al alloys (with Al contents varying from 1 to 8 wt pct) are exposed to a O2-N2 atm with 10-6 atm O2. The heating times of 1, 10, and 100 minutes to the isothermal temperature of 1558 K (1285 °C) were used. It was found that fewer sub-surface nitride precipitates formed when the heating time was lowered and when Al content in the samples was increased. In the 8 wt pct samples, no internal nitride precipitates were present regardless of heating time. In the 3 and 5 wt pct samples, internal nitride precipitates were nearly more or less absent at heating times less than 10 minutes. The decrease in internal precipitates was governed by the evolving structure of the external oxide-scale. At low heating rates and/or low Al contents, significant Fe-oxide patches formed and these appeared to allow for ingress of gaseous N2. For the slow heating rates, ingress could have happened during the longer time spent in lower temperatures where non-protective alumina was present. As Al content in the alloy was increased, the external scale was Al2O3 and/or FeAl2O4 and more continuous and consequently hindered the N2 from accessing the metal surface. Increasing the Al content in the alloy had the effect of promoting the outward diffusion of Al in the alloy and thereby assisting the formation of the continuous external layer of Al2O3 and/or FeAl2O4.

Modeling Coupled Movement of Water, Vapor, and Energy in Soils and at the Soil-Atmosphere Interface Using HYDRUS

NASA Astrophysics Data System (ADS)

Simunek, Jiri; Brunetti, Giuseppe; Saito, Hirotaka; Bristow, Keith

2017-04-01

Mass and energy fluxes in the subsurface are closely coupled and cannot be evaluated without considering their mutual interactions. However, only a few numerical models consider coupled water, vapor and energy transport in both the subsurface and at the soil-atmosphere interface. While hydrological and thermal processes in the subsurface are commonly implemented in existing models, which often consider both isothermally and thermally induced water and vapor flow, the interactions at the soil-atmosphere interface are often simplified, and the effects of slope inclination, slope azimuth, variable surface albedo and plant shading on incoming radiation and spatially variable surface mass and energy balance, and consequently on soil moisture and temperature distributions, are rarely considered. In this presentation we discuss these missing elements and our attempts to implement them into the HYDRUS model. We demonstrate implications of some of these interactions and their impact on the spatial distributions of soil temperature and water content, and their effect on soil evaporation. Additionally, we will demonstrate the use of the HYDRUS model to simulate processes relevant to the ground source heat pump systems.

Wells for In Situ Extraction of Volatiles from Regolith (WIEVR)

NASA Technical Reports Server (NTRS)

Walton, Otis R.

2013-01-01

A document discusses WIEVRs, a means to extract water ice more efficiently than previous approaches. This water may exist in subsurface deposits on the Moon, in many NEOs (Near- Earth Objects), and on Mars. The WIEVR approach utilizes heat from the Sun to vaporize subsurface ice; the water (or other volatile) vapor is transported to a surface collection vessel where it is condensed (and collected). The method does not involve mining and extracting regolith before removing the frozen volatiles, so it uses less energy and is less costly than approaches that require mining of regolith. The only drilling required for establishing the WIEVR collection/recovery system is a well-bore drill hole. In its simplest form, the WIEVRs will function without pumps, compressors, or other gas-moving equipment, relying instead on diffusive transport and thermally induced convection of the vaporized volatiles for transport to the collection location(s). These volatile extraction wells could represent a significant advance in extraction efficiency for recovery of frozen volatiles in subsurface deposits on the Moon, Mars, or other extraterrestrial bodies.

Thermostructural Evaluation of Joggle Region on the Shuttle Orbiter's Wing Leading Edge

NASA Technical Reports Server (NTRS)

Walker, Sandra P.; Warren, Jerry E.

2012-01-01

An investigation was initiated to determine the cause of coating spallation occurring on the Shuttle Orbiter's wing leading edge panels in the slip-side joggle region. The coating spallation events were observed, post flight, on differing panels on different missions. As part of the investigation, the high re-entry heating occurring on the joggles was considered here as a possible cause. Thus, a thermostructural evaluation was conducted to determine the detailed state-of-stress in the joggle region during re-entry and the feasibility of a laboratory test on a local joggle specimen to replicate this state-of-stress. A detailed three-dimensional finite element model of a panel slip-side joggle region was developed. Parametric and sensitivity studies revealed significant stresses occur in the joggle during peak heating. A critical interlaminar normal stress concentration was predicted in the substrate at the coating interface and was confined to the curved joggle region. Specifically, the high interlaminar normal stress is identified to be the cause for the occurrence of failure in the form of local subsurface material separation occurring in the slip-side joggle. The predicted critical stresses are coincident with material separations that had been observed with microscopy in joggle specimens obtained from flight panels.

Using endometrial ablation as a treatment for abnormal bleeding: energy source comparisons and clinical results

NASA Astrophysics Data System (ADS)

Ryan, Thomas P.

2000-01-01

A great number of women suffer from abnormal uterine bleeding. Most do not want to undergo a hysterectomy and have searched for an alternative treatment. Ablation of the endometrium has become a viable alternative. Initially, surgical applications utilized thermal ablation by passing a rolling electrode, energized by monopolar radiofrequency (RF) energy, to ablate the inner uterine lining. This procedure was done under visual guidance and required practiced surgical skills to perform the ablation. It was not possible to assess subsurface damage. More recently, various energy systems have been applied to the endometrium such as lasers, microwaves, monopolar and bipolar RF, hot fluid balloons, and cryotherapy. They are being used in computer controlled treatments that obviate the user's skill, and utilize a self-positioning device paired with a temperature monitored, thermal treatment. Finite element models have also been created to predict heating profiles with devices that either rely on conductive heating or that deposit power in tissue. This is a very active field in terms of innovation with creative solutions using contemporary technology to reduce or halt the bleeding. Devices and minimally invasive treatments will offer choices to women and will be able to replace a surgical procedure with an office-based procedure. They are very promising and are discussed at length herein.

Baseline hydraulic performance of the Heathrow constructed wetlands subsurface flow system.

PubMed

Richter, K M; Margetts, J R; Saul, A J; Guymer, I; Worrall, P

2003-01-01

A constructed wetland treatment system has been commissioned by BAA (formerly the British Airports Authority) in order to attenuate airfield runoff contaminated with de-icant and other potentially polluting materials from Heathrow Airport. Airfield runoff containing de-icants has the potential to impose significant oxygen demands on water bodies. The site consists of a number of integrated treatment systems, including a 1 ha rafted reed bed canal system and a 2 ha sub-surface flow gravel reed bed. This research project is concerned with the performance of the subsurface flow reed beds, though attention will be paid in this paper to the operation of the whole system. Prior to the planting of the subsurface flow reed beds, flow-tracing experiments were carried out on the three different types of subsurface flow beds, so that the baseline performance of the system could be quantified. In association, data regarding the soil organic matter content was also collected prior to the planting of the beds. As expected, soil organic matter content is observed to be negligible within the bed, though a small amount of build up was observed in localised areas on the surface of the beds. This was attributed to the growth of algae in depressions where standing water persisted during the construction phase. Few studies exist which provide detailed measurements into the cause and effect of variations in hydraulic conductivity within an operational reed bed system. The data presented here form the baseline results for an ongoing study into the investigation of the change in hydraulic conductivity of an operational reed bed system.

Structure and function of subsurface microbial communities affecting radionuclide transport and bioimmobilization

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

Kostka, Joel E.; Prakash, Om; Green, Stefan J.

2012-05-01

Our objectives were to: 1) isolate and characterize novel anaerobic prokaryotes from subsurface environments exposed to high levels of mixed contaminants (U(VI), nitrate, sulfate), 2) elucidate the diversity and distribution of metabolically active metal- and nitrate-reducing prokaryotes in subsurface sediments, and 3) determine the biotic and abiotic mechanisms linking electron transport processes (nitrate, Fe(III), and sulfate reduction) to radionuclide reduction and immobilization. Mechanisms of electron transport and U(VI) transformation were examined under near in situ conditions in sediment microcosms and in field investigations. Field sampling was conducted at the Oak Ridge Field Research Center (ORFRC), in Oak Ridge, Tennessee. Themore » ORFRC subsurface is exposed to mixed contamination predominated by uranium and nitrate. In short, we effectively addressed all 3 stated objectives of the project. In particular, we isolated and characterized a large number of novel anaerobes with a high bioremediation potential that can be used as model organisms, and we are now able to quantify the function of subsurface sedimentary microbial communities in situ using state-of-the-art gene expression methods (molecular proxies).« less

Estimating subsurface water volumes and transit times in Hokkaido river catchments, Japan, using high-accuracy tritium analysis

NASA Astrophysics Data System (ADS)

Gusyev, Maksym; Yamazaki, Yusuke; Morgenstern, Uwe; Stewart, Mike; Kashiwaya, Kazuhisa; Hirai, Yasuyuki; Kuribayashi, Daisuke; Sawano, Hisaya

2015-04-01

The goal of this study is to estimate subsurface water transit times and volumes in headwater catchments of Hokkaido, Japan, using the New Zealand high-accuracy tritium analysis technique. Transit time provides insights into the subsurface water storage and therefore provides a robust and quick approach to quantifying the subsurface groundwater volume. Our method is based on tritium measurements in river water. Tritium is a component of meteoric water, decays with a half-life of 12.32 years, and is inert in the subsurface after the water enters the groundwater system. Therefore, tritium is ideally suited for characterization of the catchment's responses and can provide information on mean water transit times up to 200 years. Only in recent years has it become possible to use tritium for dating of stream and river water, due to the fading impact of the bomb-tritium from thermo-nuclear weapons testing, and due to improved measurement accuracy for the extremely low natural tritium concentrations. Transit time of the water discharge is one of the most crucial parameters for understanding the response of catchments and estimating subsurface water volume. While many tritium transit time studies have been conducted in New Zealand, only a limited number of tritium studies have been conducted in Japan. In addition, the meteorological, orographic and geological conditions of Hokkaido Island are similar to those in parts of New Zealand, allowing for comparison between these regions. In 2014, three field trips were conducted in Hokkaido in June, July and October to sample river water at river gauging stations operated by the Ministry of Land, Infrastructure, Transport and Tourism (MLIT). These stations have altitudes between 36 m and 860 m MSL and drainage areas between 45 and 377 km2. Each sampled point is located upstream of MLIT dams, with hourly measurements of precipitation and river water levels enabling us to distinguish between the snow melt and baseflow contributions to the river discharge. For the June sampling, the tritium and stable isotope results indicate below normal river discharges with a strong contribution of snow melt at some sampling points, and relatively short groundwater transit times. The tritium concentration results are used to interpret mean transit times (MTTs) for each sampling point using a tritium input curve constructed from historical International Atomic Energy Agency and available Japanese data, and subsurface volumes are estimated from the MTTs and measured river discharges.

Exploring Liquid Water Beneath Glaciers and Permafrost in Antarctica Through Airborne Electromagnetic Surveys

NASA Astrophysics Data System (ADS)

Auken, E.; Tulaczyk, S. M.; Foley, N.; Dugan, H.; Schamper, C.; Peter, D.; Virginia, R. A.; Sørensen, K.

2015-12-01

Here, we demonstrate how high powered airborne electromagnetic resistivity is efficiently used to map 3D domains of unfrozen water below glaciers and permafrost in the cold regions of the Earth. Exploration in these parts of the world has typically been conducted using radar methods, either ground-based or from an airborne platform. Radar is an excellent method if the penetrated material has a low electrical conductivity, but in materials with higher conductivity, such as sediments with liquid water, the energy is attenuated . Such cases are efficiently explored with electromagnetic methods, which attenuate less quickly in conductive media and can therefore 'see through' conductors and return valuable information about their electrical properties. In 2011, we used a helicopter-borne, time-domain electromagnetic sensor to map resistivity in the subsurface across the McMurdo Dry Valleys (MDV). The MDV are a polar desert in coastal Antarctica where glaciers, permafrost, ice-covered lakes, and ephemeral summer streams coexist. In polar environments, this airborne electromagnetic system excels at finding subsurface liquid water, as water which remains liquid under cold conditions must be sufficiently saline, and therefore electrically conductive. In Taylor Valley, in the MDV, our data show extensive subsurface low resistivity layers beneath higher resistivity layers, which we interpret as cryoconcentrated hypersaline brines lying beneath glaciers and frozen permafrost. These brines appear to be contiguous with surface lakes, subglacial regions, and the Ross Sea, which could indicate a regional hydrogeologic system wherein solutes may be transported between surface reservoirs by ionic diffusion and subsurface flow. The system as of 2011 had a maximum exploration depth of about 300 m. However, newer and more powerful airborne systems can explore to a depth of 500 - 600 m and new ground based instruments will get to 1000 m. This is sufficient to penetrate to the base of almost all coastal Antarctic glaciers. The MDV, where conductive brines exist beneath resistive glacial ice and frozen permafrost, are especially well suited to exploration by airborne electromagnetic, but similarly suitable systems are likely to exist elsewhere in the cryosphere.

Empirical quantification of lacustrine groundwater discharge - different methods and their limitations

NASA Astrophysics Data System (ADS)

Meinikmann, K.; Nützmann, G.; Lewandowski, J.

2015-03-01

Groundwater discharge into lakes (lacustrine groundwater discharge, LGD) can be an important driver of lake eutrophication. Its quantification is difficult for several reasons, and thus often neglected in water and nutrient budgets of lakes. In the present case several methods were applied to determine the expansion of the subsurface catchment, to reveal areas of main LGD and to identify the variability of LGD intensity. Size and shape of the subsurface catchment served as a prerequisite in order to calculate long-term groundwater recharge and thus the overall amount of LGD. Isotopic composition of near-shore groundwater was investigated to validate the quality of catchment delineation in near-shore areas. Heat as a natural tracer for groundwater-surface water interactions was used to find spatial variations of LGD intensity. Via an analytical solution of the heat transport equation, LGD rates were calculated from temperature profiles of the lake bed. The method has some uncertainties, as can be found from the results of two measurement campaigns in different years. The present study reveals that a combination of several different methods is required for a reliable identification and quantification of LGD and groundwater-borne nutrient loads.

Radio Sounding Techniques for the Galilean Icy Moons and their Jovian Magnetospheric Environment

NASA Technical Reports Server (NTRS)

Green, James L.; Markus, Thursten; Fung, Shing F.; Benson, Robert F.; Reinich, Bodo W.; Song, Paul; Gogineni, S. Prasad; Cooper, John F.; Taylor, William W. L.; Garcia, Leonard

2004-01-01

Radio sounding of the Earth's topside ionosphere and magnetosphere is a proven technique from geospace missions such as the International Satellites for Ionospheric Studies (ISIS) and the Imager for Magnetopause-to-Aurora Global Exploration (IMAGE). Application of this technique to Jupiter's icy moons and the surrounding Jovian magnetosphere will provide unique remote sensing observations of the plasma and magnetic field environments and the subsurface conductivities, of Europa, Ganymede, and Callisto. Spatial structures of ionospheric plasma above the surfaces of the moons vary in response to magnetic-field perturbations from (1) magnetospheric plasma flows, (2) ionospheric currents from ionization of sputtered surface material, and (3) induced electric currents in salty subsurface oceans and from the plasma flows and ionospheric currents themselves. Radio sounding from 3 kHz to 10 MHz can provide the global electron densities necessary for the extraction of the oceanic current signals and supplements in-situ plasma and magnetic field measurements. While radio sounding requires high transmitter power for subsurface sounding, little power is needed to probe the electron density and magnetic field intensity near the spacecraft. For subsurface sounding, reflections occur at changes in the dielectric index, e.g., at the interfaces between two different phases of water or between water and soil. Variations in sub-surface conductivity of the icy moons can be investigated by radio sounding in the frequency range from 10 MHz to 50 MHz, allowing the determination of the presence of density and solid-liquid phase boundaries associated with oceans and related structures in overlying ice crusts. The detection of subsurface oceans underneath the icy crusts of the Jovian moons is one of the primary objectives of the Jupiter Icy Moons Orbiter (JIMO) mission. Preliminary modeling results show that return signals are clearly distinguishable be&een an ice crust with a thickness of 7 km on 1) an ocean and 2) a layer of bedrock. Knowledge of the ionospheric contributions to the time delay of the low-frequency subsurface radar is shown to be important in obtaining accurate depth information.

Deglacial Tropical Atlantic subsurface warming links ocean circulation variability to the West African Monsoon.

PubMed

Schmidt, Matthew W; Chang, Ping; Parker, Andrew O; Ji, Link; He, Feng

2017-11-13

Multiple lines of evidence show that cold stadials in the North Atlantic were accompanied by both reductions in Atlantic Meridional Overturning Circulation (AMOC) and collapses of the West African Monsoon (WAM). Although records of terrestrial change identify abrupt WAM variability across the deglaciation, few studies show how ocean temperatures evolved across the deglaciation. To identify the mechanism linking AMOC to the WAM, we generated a new record of subsurface temperature variability over the last 21 kyr based on Mg/Ca ratios in a sub-thermocline dwelling planktonic foraminifera in an Eastern Equatorial Atlantic (EEA) sediment core from the Niger Delta. Our subsurface temperature record shows abrupt subsurface warming during both the Younger Dryas (YD) and Heinrich Event 1. We also conducted a new transient coupled ocean-atmosphere model simulation across the YD that better resolves the western boundary current dynamics and find a strong negative correlation between AMOC strength and EEA subsurface temperatures caused by changes in ocean circulation and rainfall responses that are consistent with the observed WAM change. Our combined proxy and modeling results provide the first evidence that an oceanic teleconnection between AMOC strength and subsurface temperature in the EEA impacted the intensity of the WAM on millennial time scales.

Active cooling-based surface confinement system for thermal soil treatment

DOEpatents

Aines, R.D.; Newmark, R.L.

1997-10-28

A thermal barrier is disclosed for surface confinement with active cooling to control subsurface pressures during thermal remediation of shallow (5-20 feet) underground contaminants. If steam injection is used for underground heating, the actively cooled thermal barrier allows the steam to be injected into soil at pressures much higher (20-60 psi) than the confining strength of the soil, while preventing steam breakthrough. The rising steam is condensed to liquid water at the thermal barrier-ground surface interface. The rapid temperature drop forced by the thermal barrier drops the subsurface pressure to below atmospheric pressure. The steam and contaminant vapors are contained by the thermal blanket, which can be made of a variety of materials such as steel plates, concrete slabs, membranes, fabric bags, or rubber bladders. 1 fig.

Active cooling-based surface confinement system for thermal soil treatment

DOEpatents

Aines, Roger D.; Newmark, Robin L.

1997-01-01

A thermal barrier is disclosed for surface confinement with active cooling to control subsurface pressures during thermal remediation of shallow (5-20 feet) underground contaminants. If steam injection is used for underground heating, the actively cooled thermal barrier allows the steam to be injected into soil at pressures much higher (20-60 psi) than the confining strength of the soil, while preventing steam breakthrough. The rising steam is condensed to liquid water at the thermal barrier-ground surface interface. The rapid temperature drop forced by the thermal barrier drops the subsurface pressure to below atmospheric pressure. The steam and contaminant vapors are contained by the thermal blanket, which can be made of a variety of materials such as steel plates, concrete slabs, membranes, fabric bags, or rubber bladders.

Fiber Optic Thermal Health Monitoring of Composites

NASA Technical Reports Server (NTRS)

Wu, Meng-Chou; Winfree, William P.; Moore, Jason P.

2010-01-01

A recently developed technique is presented for thermographic detection of flaws in composite materials by performing temperature measurements with fiber optic Bragg gratings. Individual optical fibers with multiple Bragg gratings employed as surface temperature sensors were bonded to the surfaces of composites with subsurface defects. The investigated structures included a 10-ply composite specimen with subsurface delaminations of various sizes and depths. Both during and following the application of a thermal heat flux to the surface, the individual Bragg grating sensors measured the temporal and spatial temperature variations. The data obtained from grating sensors were analyzed with thermal modeling techniques of conventional thermography to reveal particular characteristics of the interested areas. Results were compared with the calculations using numerical simulation techniques. Methods and limitations for performing in-situ structural health monitoring are discussed.

The Guaymas Basin Hiking Guide to Hydrothermal Mounds, Chimneys, and Microbial Mats: Complex Seafloor Expressions of Subsurface Hydrothermal Circulation

PubMed Central

Teske, Andreas; de Beer, Dirk; McKay, Luke J.; Tivey, Margaret K.; Biddle, Jennifer F.; Hoer, Daniel; Lloyd, Karen G.; Lever, Mark A.; Røy, Hans; Albert, Daniel B.; Mendlovitz, Howard P.; MacGregor, Barbara J.

2016-01-01

The hydrothermal mats, mounds, and chimneys of the southern Guaymas Basin are the surface expression of complex subsurface hydrothermal circulation patterns. In this overview, we document the most frequently visited features of this hydrothermal area with photographs, temperature measurements, and selected geochemical data; many of these distinct habitats await characterization of their microbial communities and activities. Microprofiler deployments on microbial mats and hydrothermal sediments show their steep geochemical and thermal gradients at millimeter-scale vertical resolution. Mapping these hydrothermal features and sampling locations within the southern Guaymas Basin suggest linkages to underlying shallow sills and heat flow gradients. Recognizing the inherent spatial limitations of much current Guaymas Basin sampling calls for comprehensive surveys of the wider spreading region. PMID:26925032

Extraction and Capture of Water from Martian Regolith Experimental Proof-of-Concept

NASA Technical Reports Server (NTRS)

Linne, Diane L.; Kleinhenz, Julie E.; Bauman, Steven W.; Johnson, Kyle A.

2016-01-01

A novel concept for extraction of water from the Mars soil in a real-time, open-air process was demonstrated in a Mars environment chamber. The concept breadboard uses radiative heating to bake off water from exposed soil contained in a bin. An enclosure, intended to mimic the bottom of a rover, covers the bin. A fan continuously blows the Mars atmospheric gases through the enclosure to collect the evolved water while a tiller was used to churn up moist subsurface soil. These initial tests verified concept feasibility. The sweep gas generated by commercially available muffin fans at 7 Torr was sufficient to transfer water vapor into a condenser flow loop. The radiative heating, while non-optimized, heated the soil surface to 60 C to generate water vapor. A rototiller working through the soil bin brought sufficient amounts of new moist soil to the heated surface to show an increase in rate of water extraction.

Assessment of the subsurface hydrology of the UIC-NARL main camp, near Barrow, Alaska, 1993-94

USGS Publications Warehouse

McCarthy, K.A.; Solin, G.L.

1995-01-01

Imikpuk Lake serves as the drinking-water source for the Ukpeagvik Inupiat Corporation-National Arctic Research Laboratory (UIC-NARL, formerly known as the Naval Arctic Research Laboratory) near Barrow, Alaska. Previously acceptable hazardous-waste disposal practices and accidental releases of various fuels and solvents during the past several decades have resulted in contamination of soil and ground water in the vicinity of the lake. As part of an assessment of the risk that subsurface contamination poses to the quality of water in the lake, the subsurface hydrology of the UIC-NARL main camp was examined. The study area is located approximately 530 kilometers north of the Arctic Circle, on the northern coast of Alaska, and the short annual thaw season and the presence of shallow, areally continuous permafrost restrict hydrologic processes. A transient ground-water system is present within the active layer-the shallow subsurface layer that thaws each summer and refreezes each winter. Water-level and thaw-depth data collected during the summers of 1993 and 1994 show that the configurations of both the water table and the subsurface frost govern the ground- water flow system in the UIC-NARL main camp and indicate that recharge to and discharge from the system are small. Spatial irregularities in the vertical extent of the active layer result from variations in land-surface elevation, variations in soil type, and the presence of buildings and other structures that either act as a heat source or block heat transfer to and from the subsurface. Distinct features in the active-layer hydrologic system in the UIC-NARL main camp include a permafrost ridge, which generally acts as a flow-system divide between the Arctic Ocean and inland water bodies; a mound in the water table, which indicates increased impedance to ground- water flow toward Imikpuk Lake and acts as a flow-system divide between the lake and Middle Salt Lagoon; and a depression in the water table, which suggests a local breach in the permafrost ridge that allows some ground water to flow directly from the main camp to the Arctic Ocean. Similar thaw depths and water-table elevations were measured during the summers of 1993 and 1994, and little change occurred in the thickness of the ground-water zone between mid- and late-thaw- season measurements. These data suggest that the system is in a state of quasi-equilibrium and that ground-water discharge is small. The observed drop in the water table as the active layer develops over the summer is probably largely the result of evapotranspiration losses rather than system outflow.

Sea ice and oceanic processes on the Ross Sea continental shelf

NASA Astrophysics Data System (ADS)

Jacobs, S. S.; Comiso, J. C.

1989-12-01

We have investigated the spatial and temporal variability of Antarctic sea ice concentrations on the Ross Sea continental shelf, in relation to oceanic and atmospheric forcing. Sea ice data were derived from Nimbus 7 scanning multichannel microwave radiometer (SMMR) brightness temperatures from 1979-1986. Ice cover over the shelf was persistently lower than above the adjacent deep ocean, averaging 86% during winter with little month-to-month or interannual variability. The large spring Ross Sea polynya on the western shelf results in a longer period of summer insolation, greater surface layer heat storage, and later ice formation in that region the following autumn. Newly identified Pennell and Ross Passage polynyas near the continental shelf break appear to be maintained in part by divergence above a submarine bank and by upwelling of warmer water near the slope front. Warmer subsurface water enters the shelf region year-round and will retard ice growth and enhance heat flux to the atmosphere when entrained in the strong winter vertical circulation. Temperatures at 125-m depth on a mooring near the Ross Ice Shelf during July 1984 averaged 0.15°C above freezing, sufficient to support a vertical heat flux above 100 W/m2. Monthly average subsurface ocean temperatures along the Ross Ice Shelf lag the air temperature cycle and begin to rise several weeks before spring ice breakout. The coarse SMMR resolution and dynamic ice shelf coastlines can compromise the use of microwave sea ice data near continental boundaries.

Comparison and analysis of empirical equations for soil heat flux for different cropping systems and irrigation methods

USGS Publications Warehouse

Irmak, A.; Singh, Ramesh K.; Walter-Shea, Elizabeth; Verma, S.B.; Suyker, A.E.

2011-01-01

We evaluated the performance of four models for estimating soil heat flux density (G) in maize (Zea mays L.) and soybean (Glycine max L.) fields under different irrigation methods (center-pivot irrigated fields at Mead, Nebraska, and subsurface drip irrigated field at Clay Center, Nebraska) and rainfed conditions at Mead. The model estimates were compared against measurements made during growing seasons of 2003, 2004, and 2005 at Mead and during 2005, 2006, and 2007 at Clay Center. We observed a strong relationship between the G and net radiation (Rn) ratio (G/Rn) and the normalized difference vegetation index (NDVI). When a significant portion of the ground was bare soil, G/Rn ranged from 0.15 to 0.30 and decreased with increasing NDVI. In contrast to the NDVI progression, the G/Rn ratio decreased with crop growth and development. The G/Rn ratio for subsurface drip irrigated crops was smaller than for the center-pivot irrigated crops. The seasonal average G was 13.1%, 15.2%, 10.9%, and 12.8% of Rn for irrigated maize, rainfed maize, irrigated soybean, and rainfed soybean, respectively. Statistical analyses of the performance of the four models showed a wide range of variation in G estimation. The root mean square error (RMSE) of predictions ranged from 15 to 81.3 W m-2. Based on the wide range of RMSE, it is recommended that local calibration of the models should be carried out for remote estimation of soil heat flux.

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

NASA Astrophysics Data System (ADS)

Tavakolian, Pantea; Sivagurunathan, Koneswaran; Mandelis, Andreas

2017-07-01

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

Automated permanent resistivity monitoring of charge and discharge processes of subsurface aquifer at the Membach station, Belgium

NASA Astrophysics Data System (ADS)

Deceuster, J.; Kaufmann, O.; van Camp, M. J.; Lecocq, T.

2010-12-01

Permanent monitoring of changes in soil properties is of increasing interest in many engineering applications such as management of groundwater contamination, landslide and sinkhole risks prevention, detection of saline water intrusion, comprehension of charge and discharge processes of subsurface aquifer. As geophysical investigations allow detecting contrasts in physical properties of the subsurface, field and lab experiments have been conducted for a few years to assess the reliability of these methods to monitor temporal changes in soil properties. Among the methods available, DC resistivity tomography is recognized as one of the most promising techniques. In order to assess the efficiency of electrical resistivity in monitoring charge and discharge processes of subsurface aquifer, and also to better model hydrological effects on the gravity measurements, an on-going field experiment is conducted at the Membach station located in the eastern part of Belgium. This geophysical station is equipped with an accelerometer, seismometers and a superconducting gravimeter, installed at the end of a 130 m long tunnel excavated in a low-porosity argillaceous sandstone mount at 48.5 m depth. Continuous gravimetric observations have been taken since August 1995. Since 2004 rainfall and soil moisture changes are measured in situ. In July 2010, an automated permanent geoelectrical acquisition system was installed to monitor subsurface resistivity variations during a test period of about 6 months. The aim of this experiment is to better understand charge and discharge processes of the subsurface aquifer, which are expected to be mainly due to rainfall variations. This aquifer is localized at the top of the weathered bedrock at a depth of 4 to 5 meters. The acquisition system consists in a straight profile of 48 buried electrodes (with a 2 meters spacing) connected to a Syscal R1 resistivimeter which is automatically controlled by a computer. Resistivity measurements are taken at least twice a day at fixed hours using a combination of dipole-dipole and Wenner-Schlumberger arrays. Acquired data are filtered in order to reject faulty measures. Time-lapse inversion (Loke (1999)) is then carried out to reconstruct a 2D model of resistivity changes. Preliminary results obtained during July show changes in inverted resistivities of about 30% in the first 4 to 5 meters layer. These observations are consistent with changes in measured gravimetric water content. This seems to indicate that subsurface aquifer charge and discharge processes are mainly due to rainfall, as expected. However, inversion errors remain high even after data filtering. This could be a consequence of weather occurring in July, leading to a poor contact between the electrodes and dry host soils near the surface. This problem should not happen anymore as the rest of the monitoring experiment is conducted during the wet season. Acknowledgments This work is conducted under the auspices of the Walloon Region Ministry under the First Spin-Off program (visa n° 916974).

Advanced Coupled Simulation of Borehole Thermal Energy Storage Systems and Above Ground Installations

NASA Astrophysics Data System (ADS)

Welsch, Bastian; Rühaak, Wolfram; Schulte, Daniel O.; Bär, Kristian; Sass, Ingo

2016-04-01

Seasonal thermal energy storage in borehole heat exchanger arrays is a promising technology to reduce primary energy consumption and carbon dioxide emissions. These systems usually consist of several subsystems like the heat source (e.g. solarthermics or a combined heat and power plant), the heat consumer (e.g. a heating system), diurnal storages (i.e. water tanks), the borehole thermal energy storage, additional heat sources for peak load coverage (e.g. a heat pump or a gas boiler) and the distribution network. For the design of an integrated system, numerical simulations of all subsystems are imperative. A separate simulation of the borehole energy storage is well-established but represents a simplification. In reality, the subsystems interact with each other. The fluid temperatures of the heat generation system, the heating system and the underground storage are interdependent and affect the performance of each subsystem. To take into account these interdependencies, we coupled a software for the simulation of the above ground facilities with a finite element software for the modeling of the heat flow in the subsurface and the borehole heat exchangers. This allows for a more realistic view on the entire system. Consequently, a finer adjustment of the system components and a more precise prognosis of the system's performance can be ensured.

Dynamic underground stripping: steam and electric heating for in situ decontamination of soils and groundwater

DOEpatents

Daily, W.D.; Ramirez, A.L.; Newmark, R.L.; Udell, K.; Buetnner, H.M.; Aines, R.D.

1995-09-12

A dynamic underground stripping process removes localized underground volatile organic compounds from heterogeneous soils and rock in a relatively short time. This method uses steam injection and electrical resistance heating to heat the contaminated underground area to increase the vapor pressure of the contaminants, thus speeding the process of contaminant removal and making the removal more complete. The injected steam passes through the more permeable sediments, distilling the organic contaminants, which are pumped to the surface. Large electrical currents are also applied to the contaminated area, which heat the impermeable subsurface layers that the steam has not penetrated. The condensed and vaporized contaminants are withdrawn by liquid pumping and vacuum extraction. The steam injection and electrical heating steps are repeated as necessary. Geophysical imaging methods can be used to map the boundary between the hot, dry, contamination-free underground zone and the cool, damp surrounding areas to help monitor the dynamic stripping process. 4 figs.

Dynamic underground stripping: steam and electric heating for in situ decontamination of soils and groundwater

DOEpatents

Daily, William D.; Ramirez, Abelardo L.; Newmark, Robin L.; Udell, Kent; Buetnner, Harley M.; Aines, Roger D.

1995-01-01

A dynamic underground stripping process removes localized underground volatile organic compounds from heterogeneous soils and rock in a relatively short time. This method uses steam injection and electrical resistance heating to heat the contaminated underground area to increase the vapor pressure of the contaminants, thus speeding the process of contaminant removal and making the removal more complete. The injected steam passes through the more permeable sediments, distilling the organic contaminants, which are pumped to the surface. Large electrical currents are also applied to the contaminated area, which heat the impermeable subsurface layers that the steam has not penetrated. The condensed and vaporized contaminants are withdrawn by liquid pumping and vacuum extraction. The steam injection and electrical heating steps are repeated as necessary. Geophysical imaging methods can be used to map the boundary between the hot, dry, contamination-free underground zone and the cool, damp surrounding areas to help monitor the dynamic stripping process.

Starting Conditions for Hydrothermal Systems Underneath Martian Craters: Hydrocode Modeling

NASA Technical Reports Server (NTRS)

Pierazzo, E.; Artemieva, N. A.; Ivanov, B. A.

2004-01-01

Mars is the most Earth-like of the Solar System s planets, and the first place to look for any sign of present or past extraterrestrial life. Its surface shows many features indicative of the presence of surface and sub-surface water, while impact cratering and volcanism have provided temporary and local surface heat sources throughout Mars geologic history. Impact craters are widely used ubiquitous indicators for the presence of sub-surface water or ice on Mars. In particular, the presence of significant amounts of ground ice or water would cause impact-induced hydrothermal alteration at Martian impact sites. The realization that hydrothermal systems are possible sites for the origin and early evolution of life on Earth has given rise to the hypothesis that hydrothermal systems may have had the same role on Mars. Rough estimates of the heat generated in impact events have been based on scaling relations, or thermal data based on terrestrial impacts on crystalline basements. Preliminary studies also suggest that melt sheets and target uplift are equally important heat sources for the development of a hydrothermal system, while its lifetime depends on the volume and cooling rate of the heat source, as well as the permeability of the host rocks. We present initial results of two-dimensional (2D) and three-dimensional (3D) simulations of impacts on Mars aimed at constraining the initial conditions for modeling the onset and evolution of a hydrothermal system on the red planet. Simulations of the early stages of impact cratering provide an estimate of the amount of shock melting and the pressure-temperature distribution in the target caused by various impacts on the Martian surface. Modeling of the late stage of crater collapse is necessary to characterize the final thermal state of the target, including crater uplift, and distribution of the heated target material (including the melt pool) and hot ejecta around the crater.

Evolution of Planetary Ice-Ocean Systems: Effects of Salinity

NASA Astrophysics Data System (ADS)

Allu Peddinti, D.; McNamara, A. K.

2015-12-01

Planetary oceanography is enjoying renewed attention thanks to not only the detection of several exoplanetary ocean worlds but also due to the expanding family of ocean worlds within our own star system. Our solar system is now believed to host about nine ocean worlds including Earth, some dwarf planets and few moons of Jupiter and Saturn. Amongst them, Europa, like Earth is thought to have an ice Ih-liquid water system. However, the thickness of the Europan ice-ocean system is much larger than that of the Earth. The evolution of this system would determine the individual thicknesses of the ice shell and the ocean. In turn, these thicknesses can alter the course of evolution of the system. In a pure H2O system, the thickness of the ice shell would govern if heat loss occurs entirely by conduction or if the shell begins to convect as it attains a threshold thickness. This switch between conduction-convection regimes could determine the longevity of the subsurface ocean and hence define the astrobiological potential of the planetary body at any given time. In reality, however, the system is not pure water ice. The detected induced magnetic field infers a saline ocean layer. Salts are expected to act as an anti-freeze allowing a subsurface ocean to persist over long periods but the amount of salts would determine the extent of that effect. In our current study, we use geodynamic models to examine the effect of salinity on the evolution of ice-ocean system. An initial ocean with different salinities is allowed to evolve. The effect of salinity on thickness of the two layers at any time is examined. We also track how salinity controls the switch between conductive-convective modes. The study shows that for a given time period, larger salinities can maintain a thick vigorously convecting ocean while the smaller salinities behave similar to a pure H2O system leading to a thick convecting ice-shell. A range of salinities identified can potentially predict the current state and possibly the intermediate states of the ice-ocean system as it evolved over time. This could help constrain the endogenic contribution of salts to the surface chemistry.

Boreal Forest Permafrost Sensitivity Ecotypes to changes in Snow Depth and Soil Moisture

NASA Astrophysics Data System (ADS)

Dabbs, A.; Romanovsky, V. E.; Kholodov, A. L.

2017-12-01

Changes in the global climate, pronounced especially in polar regions due to their accelerated warming, are expected by many global climate models to have large impacts on the moisture budget throughout the world. Permafrost extent and the soil temperature regime are both strongly dependent on soil moisture and snow depth because of their immense effects on the thermal properties of the soil column and surface energy balance respectively. To assess how the ground thermal regime at various ecotypes may react to a change in the moisture budget, we performed a sensitivity analysis using the Geophysical Institute Permafrost Laboratory model, which simulates subsurface temperature dynamics by solving a one-dimensional nonlinear heat equation with phase change. We used snow depth and air temperature data from the Fairbanks International Airport meteorological station as forcing for this sensitivity analysis. We looked at five different ecotypes within the boreal forest region of Alaska: mixed, deciduous and black forests, willow shrubs and tundra. As a result of this analysis, we found that ecotypes with higher soil moisture contents, such as willow shrubs, are most sensitive to changes in snow depth due to the larger amount of latent heat trapped underneath the snow during the freeze up of active layer. In addition, soil within these ecotypes has higher thermal conductivity due to high saturation degree allowing for deeper seasonal freezing. Also, we found that permafrost temperatures were most sensitive to changes in soil moisture in ecotypes that were not completely saturated such as boreal forest. These ecotypes lacked complete saturation because of thick organic layers that have very high porosities or partially drained mineral soils. Contrarily, tundra had very little response to changes in soil moisture due to its thin organic layer and almost completely saturated soil column. This difference arises due to the disparity between the frozen and unfrozen thermal conductivities of the soil. In highly saturated soils, the frozen thermal conductivity of the soil can be more than double that of the unfrozen thermal conductivity while in dryer soils that ratio reduces down to less than 1.5. This difference allows the seasonal freezing to penetrate quicker and deeper causing even more latent heat to be released and trapped.

Application of electromagnetic techniques in survey of contaminated groundwater at an abandoned mine complex in southwestern Indiana, U.S.A.

USGS Publications Warehouse

Brooks, G.A.; Olyphant, G.A.; Harper, D.

1991-01-01

In part of a large abandoned mining complex, electromagnetic geophysical surveys were used along with data derived from cores and monitoring wells to infer sources of contamination and subsurface hydrologic connections between acidic refuse deposits and adjacent undisturbed geologic materials. Electrical resistivity increases sharply along the boundary of an elevated deposit of pyritic coarse refuse, which is highly contaminated and electrically conductive, indicating poor subsurface hydrologic connections with surrounding deposits of fine refuse and undisturbed glacial material. Groundwater chemistry, as reflected in values of specific conductance, also differs markedly across the deposit's boundary, indicating that a widespread contaminant plume has not developed around the coarse refuse in more than 40 yr since the deposit was created. Most acidic drainage from the coarse refuse is by surface runoff and is concentrated around stream channels. Although most of the contaminated groundwater within the study area is concentrated within the surficial refuse deposits, transects of apparent resistivity and phase angle indicate the existence of an anomalous conductive layer at depth (>4 m) in thick alluvial sediments along the northern boundary of the mining complex. Based on knowledge of local geology, the anomaly is interpreted to represent a subsurface connection between the alluvium and a flooded abandoned underground mine. ?? 1991 Springer-Verlag New York Inc.

Application of electromagnetic techniques in survey of contaminated groundwater at an abandoned mine complex in southwestern Indiana, U.S.A.

NASA Astrophysics Data System (ADS)

Brooks, Glenn A.; Olyphant, Greg A.; Harper, Denver

1991-07-01

In part of a large abandoned mining complex, electromagnetic geophysical surveys were used along with data derived from cores and monitoring wells to infer sources of contamination and subsurface hydrologic connections between acidic refuse deposits and adjacent undisturbed geologic materials. Electrical resistivity increases sharply along the boundary of an elevated deposit of pyritic coarse refuse, which is highly contaminated and electrically conductive, indicating poor subsurface hydrologic connections with surrounding deposits of fine refuse and undisturbed glacial material. Groundwater chemistry, as reflected in values of specific conductance, also differs markedly across the deposit's boundary, indicating that a widespread contaminant plume has not developed around the coarse refuse in more than 40 yr since the deposit was created. Most acidic drainage from the coarse refuse is by surface runoff and is concentrated around stream channels. Although most of the contaminated groundwater within the study area is concentrated within the surficial refuse deposits, transects of apparent resistivity and phase angle indicate the existence of an anomalous conductive layer at depth (>4 m) in thick alluvial sediments along the northern boundary of the mining complex. Based on knowledge of local geology, the anomaly is interpreted to represent a subsurface connection between the alluvium and a flooded abandoned underground mine.

Impact of Land Model Depth on Long Term Climate Variability and Change.

NASA Astrophysics Data System (ADS)

Gonzalez-Rouco, J. F.; García-Bustamante, E.; Hagemann, S.; Lorentz, S.; Jungclaus, J.; de Vrese, P.; Melo, C.; Navarro, J.; Steinert, N.

2017-12-01

The available evidence indicates that the simulation of subsurface thermodynamics in current General Circulation Models (GCMs) is not accurate enough due to the land-surface model imposing a zero heat flux boundary condition that is too close to the surface. Shallow land model components distort the amplitude and phase of the heat propagation in the subsurface with implications for energy storage and land-air interactions. Off line land surface model experiments forced with GCM climate change simulations and comparison with borehole temperature profiles indicate there is a large reduction of the energy storage of the soil using the typical shallow land models included in most GCMs. However, the impact of increasing the depth of the soil model in `on-line' GCM simulations of climate variability or climate change has not yet been systematically explored. The JSBACH land surface model has been used in stand alone mode, driven by outputs of the MPIESM to assess the impacts of progressively increasing the depth of the soil model. In a first stage, preindustrial control simulations are developed increasing the lower depth of the zero flux bottom boundary condition placed for temperature at the base of the fifth model layer (9.83 m) down to 294.6 m (layer 9), thus allowing for the bottom layers to reach equilibrium. Starting from piControl conditions, historical and scenario simulations have been performed since 1850 yr. The impact of increasing depths on the subsurface layer temperatures is analysed as well as the amounts of energy involved. This is done also considering permafrost processes (freezing and thawing). An evaluation on the influence of deepening the bottom boundary on the simulation of low frequency variability and temperature trends is provided.

Nuclear subsurface explosion modeling and hydrodynamic fragmentation simulation of hazardous asteroids

NASA Astrophysics Data System (ADS)

Premaratne, Pavithra Dhanuka

Disruption and fragmentation of an asteroid using nuclear explosive devices (NEDs) is a highly complex yet a practical solution to mitigating the impact threat of asteroids with short warning time. A Hypervelocity Asteroid Intercept Vehicle (HAIV) concept, developed at the Asteroid Deflection Research Center (ADRC), consists of a primary vehicle that acts as kinetic impactor and a secondary vehicle that houses NEDs. The kinetic impactor (lead vehicle) strikes the asteroid creating a crater. The secondary vehicle will immediately enter the crater and detonate its nuclear payload creating a blast wave powerful enough to fragment the asteroid. The nuclear subsurface explosion modeling and hydrodynamic simulation has been a challenging research goal that paves the way an array of mission critical information. A mesh-free hydrodynamic simulation method, Smoothed Particle Hydrodynamics (SPH) was utilized to obtain both qualitative and quantitative solutions for explosion efficiency. Commercial fluid dynamics packages such as AUTODYN along with the in-house GPU accelerated SPH algorithms were used to validate and optimize high-energy explosion dynamics for a variety of test cases. Energy coupling from the NED to the target body was also examined to determine the effectiveness of nuclear subsurface explosions. Success of a disruption mission also depends on the survivability of the nuclear payload when the secondary vehicle approaches the newly formed crater at a velocity of 10 km/s or higher. The vehicle may come into contact with debris ejecting the crater which required the conceptual development of a Whipple shield. As the vehicle closes on the crater, its skin may also experience extreme temperatures due to heat radiated from the crater bottom. In order to address this thermal problem, a simple metallic thermal shield design was implemented utilizing a radiative heat transfer algorithm and nodal solutions obtained from hydrodynamic simulations.

Channel Transmission Loss Studies During Ephemeral Flow Events: ER-5-3 Channel and Cambric Ditch, Nevada Test Site, Nye County, Nevada

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

J.J. Miller; S.A. Mizell; R.H. French

2005-10-01

Transmission losses along ephemeral channels are an important, yet poorly understood, aspect of rainfall-runoff prediction. Losses occur as flow infiltrates channel bed, banks, and floodplains. Estimating transmission losses in arid environments is difficult because of the variability of surficial geomorphic characteristics and infiltration capacities of soils and near-surface low-permeability geologic layers (e.g., calcrete). Transmission losses in ephemeral channels are nonlinear functions of discharge and time (Lane, 1972), and vary spatially along the channel reach and with soil antecedent moisture conditions (Sharma and Murthy, 1994). Rainfall-runoff models used to estimate peak discharge and runoff volume for flood hazard assessment are notmore » designed specifically for ephemeral channels, where transmission loss can be significant because of the available storage volume in channel soils. Accuracy of the flow routing and rainfall-runoff models is dependent on the transmission loss estimate. Transmission loss rate is the most uncertain parameter in flow routing through ephemeral channels. This research, sponsored by the U.S. Department of Energy, National Nuclear Security Administration (DOE/NNSA) and conducted at the Nevada Test Site (NTS), is designed to improve understanding of the impact of transmission loss on ephemeral flood modeling and compare various methodologies for predicting runoff from rainfall events. Various applications of this research to DOE projects include more site-specific accuracy in runoff prediction; possible reduction in size of flood mitigation structures at the NTS; and a better understanding of expected infiltration from runoff losses into landfill covers. Two channel transmission loss field experiments were performed on the NTS between 2001 and 2003: the first was conducted in the ER-5-3 channel (Miller et al., 2003), between March and June 2001, and the second was conducted in the Cambric Ditch (Mizell et al., 2005), between April and July 2003. Both studies used water discharged from unrelated drilling activities during well development and aquifer pump tests. Discharge measurements at several flumes located along the channels were used to directly measure transmission losses. Flume locations were chosen in relation to geomorphic surface types and ages, vegetative cover and types, subsurface indurated layers (calcrete), channel slopes, etc. Transmission losses were quantified using three different analysis methods. Method 1 uses Lane's Method (Lane, 1983) for estimating flood magnitude in ephemeral channels. Method 2 uses heat as a subsurface tracer for infiltration. Numerical modeling, using HYDRUS-2D (Simunek et al., 1999), a finite-element-based flow and transport code, was applied to estimate infiltration from soil temperature data. Method 3 uses hydraulic gradient and water content in a Darcy's Law approach (Freeze and Cherry, 1979) to calculate one-dimensional flow rates. Heat dissipation and water content data were collected for this analysis.« less

An estimation of the electrical characteristics of planetary shallow subsurfaces with TAPIR antennas

NASA Astrophysics Data System (ADS)

Le Gall, A.; Reineix, A.; Ciarletti, V.; Berthelier, J. J.; Ney, R.; Dolon, F.; Corbel, C.

2006-06-01

In the frame of the NETLANDER program, we have developed the Terrestrial And Planetary Investigation by Radar (TAPIR) imaging ground-penetrating radar to explore the Martian subsurface at kilometric depths and search for potential water reservoirs. This instrument which is to operate from a fixed lander is based on a new concept which allows one to image the various underground reflectors by determining the direction of propagation of the reflected waves. The electrical parameters of the shallow subsurface (permittivity and conductivity) need to be known to correctly determine the propagation vector. In addition, these electrical parameters can bring valuable information on the nature of the materials close to the surface. The electric antennas of the radar are 35 m long resistively loaded monopoles that are laid on the ground. Their impedance, measured during a dedicated mode of operation of the radar, depends on the electrical parameters of soil and is used to infer the permittivity and conductivity of the upper layer of the subsurface. This paper presents an experimental and theoretical study of the antenna impedance and shows that the frequency profile of the antenna complex impedance can be used to retrieve the geoelectrical characteristics of the soil. Comparisons between a numerical modeling and in situ measurements have been successfully carried over various soils, showing a very good agreement.

Application of ground-penetrating radar methods in determining hydrogeologic conditions in a karst area, west-central Florida

USGS Publications Warehouse

Barr, G.L.

1993-01-01

Ground-penetrating radar (GPR) is useful as a surface geophysical method for exploring geology and subsurface features in karst settings. Interpretation of GPR data was used to infer lithology and hydrogeologic conditions in west-central Florida. This study demonstrates how GPR methods can be used to investigate the hydrogeology of an area. GPR transmits radio- frequency electromagnetic waves into the ground and receives reflected energy waves from subsurface interfaces. Subsurface profiles showing sediment thickness, depth to water table and clay beds, karst development, buried objects, and lake-bottom structure were produced from GPR traverses obtained during December 1987 and March 1990 in Pinellas, Hillsborough, and Hardee Counties in west-central Florida. Performance of the GPR method is site specific, and data collected are principally affected by the sediment and pore fluids, conductances and dielectric constants. Effective exploration depths of the GPR surveys through predominately unsaturated and saturated sand and clay sediments at five study sites ranged from a few feet to greater than 50 feet below land surface. Exploration depths were limited when high conductivity clay was encountered, whereas greater exploration depths were possible in material composed of sand. Application of GPR is useful in profiling subsurface conditions, but proper interpretation depends upon the user's knowledge of the equipment and the local hydrogeological setting, as well as the ability to interpret the graphic profile.

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

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

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

1998-06-01

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

Thermal inertia mapping of below ground objects and voids

NASA Astrophysics Data System (ADS)

Del Grande, Nancy K.; Ascough, Brian M.; Rumpf, Richard L.

2013-05-01

Thermal inertia (effusivity) contrast marks the borders of naturally heated below ground object and void sites. The Dual Infrared Effusivity Computed Tomography (DIRECT) method, patent pending, detects and locates the presence of enhanced heat flows from below ground object and void sites at a given area. DIRECT maps view contrasting surface temperature differences between sites with normal soil and sites with soil disturbed by subsurface, hollow or semi-empty object voids (or air gaps) at varying depths. DIRECT utilizes an empirical database created to optimize the scheduling of daily airborne thermal surveys to view and characterize unseen object and void types, depths and volumes in "blind" areas.

A synchronized particle image velocimetry and infrared thermography technique applied to an acoustic streaming flow

PubMed Central

Sou, In Mei; Layman, Christopher N.; Ray, Chittaranjan

2013-01-01

Subsurface coherent structures and surface temperatures are investigated using simultaneous measurements of particle image velocimetry (PIV) and infrared (IR) thermography. Results for coherent structures from acoustic streaming and associated heating transfer in a rectangular tank with an acoustic horn mounted horizontally at the sidewall are presented. An observed vortex pair develops and propagates in the direction along the centerline of the horn. From the PIV velocity field data, distinct kinematic regions are found with the Lagrangian coherent structure (LCS) method. The implications of this analysis with respect to heat transfer and related sonochemical applications are discussed. PMID:24347810

Induction signals from Callisto's ionosphere and their implications on a possible subsurface ocean

NASA Astrophysics Data System (ADS)

Hartkorn, Oliver; Saur, Joachim

2017-11-01

We investigate whether induction within Callisto's electrically conductive ionosphere can explain observed magnetic fields which have previously been interpreted as evidence of induction in a saline, electrically conductive subsurface ocean. Callisto's ionosphere is subject to the flow of time-periodic magnetized plasma of Jupiter's magnetosphere, which induces electric fields and electric currents in Callisto's electrically conductive ionosphere. We develop a simple analytic model for a first quantitative understanding of the effects of induction in Callisto's ionosphere caused by the interaction with a time-variable magnetic field environment. With this model, we also investigate how the associated ionospheric currents close in the ambient magnetospheric plasma. Based on our model, we find that the anisotropic nature of Callisto's ionospheric conductivity generates an enhancement effect on ionospheric loop currents which are driven by the time-variable magnetic field. This effect is similar to the Cowling channel effect known from Earth's ionosphere. Subsequently, we numerically calculate the expected induced magnetic fields due to Jupiter's time-variable magnetic field in an anisotropic conductive ionosphere and compare our results with the Galileo C-3 and C-9 flybys. We find that induction within Callisto's ionosphere is responsible for a significant part of the observed magnetic fields. Ionospheric induction creates induced magnetic fields to some extent similar as expected from a subsurface water ocean. Depending on currently unknown properties such as Callisto's nightside ionosphere, the existence of layers of "dirty ice" and the details of the plasma interaction, a water ocean might be located much deeper than previously thought or might not exist at all.

Monitoring an Induced Permafrost Warming Experiment Using ERT, Temperature, and NMR in Fairbanks, Alaska

NASA Astrophysics Data System (ADS)

Ulrich, C.; Ajo Franklin, J. B.; Ekblaw, I.; Lindsey, N.; Wagner, A. M.; Saari, S.; Daley, T. M.; Freifeld, B. M.

2016-12-01

As global temperatures continue to rise, permafrost landscapes will experience more rapid changes than other global climate zones. Permafrost thaw is a result of increased temperatures in arctic settings resulting in surface deformation and subsurface hydrology changes. From an engineering perspective, surface deformation poses a threat to the stability of existing infrastructure such as roads, utility piping, and building structures. Preemptively detecting or monitoring subsurface thaw dynamics presents a difficult challenge due to the long time scales as deformation occurs. Increased subsurface moisture content results from permafrost thaw of which electrical resistivity tomography (ERT), soil temperature, and nuclear magnetic resonance (NMR) are directly sensitive. In this experiment we evaluate spatial and temporal changes in subsurface permafrost conditions (moisture content and temperature) at a experimental heating plot in Fairbanks, AK. This study focuses on monitoring thaw signatures using multiple collocated electrical resistivity (ERT), borehole temperature, and borehole nuclear magnetic resonance (NMR) measurements. Timelapse ERT (sensitive to changes in moisture content) was inverted using collocated temperature and NMR to constrain ERT inversions. Subsurface thermal state was monitored with timelapse thermistors, sensitive to soil ice content. NMR was collected in multiple boreholes and is sensitive to changes in moisture content and pore scale distribution. As permafrost thaws more hydrogen, in the form of water, is available resulting in a changing NMR response. NMR requires the availability of liquid water in order to induce spin of the hydrogen molecule, hence, if frozen water molecules will be undetectable. In this study, the permafrost is poised close to 0oC and is mainly silt with small pore dimensions; this combination makes NMR particularly useful due to the possibility of sub-zero thaw conditions within the soil column. Overall this experiment presents a complementary suite of methods that provides feedback on subsurface permafrost state even in cases where soil texture might control unfrozen water content.

Interactions among hydraulic conductivity distributions, subsurface topography, and transport thresholds revealed by a multitracer hillslope irrigation experiment

DOE PAGES

Jackson, C. Rhett; Du, Enhao; Klaus, Julian; ...

2016-08-12

Interactions among hydraulic conductivity distributions, subsurface topography, and lateral flow are poorly understood. We applied 407 mm of water and a suite of tracers over 51 h to a 12 by 16.5 m forested hillslope segment to determine interflow thresholds, preferential pathway pore velocities, large-scale conductivities, the time series of event water fractions, and the fate of dissolved nutrients. The 12% hillslope featured loamy sand A and E horizons overlying a sandy clay loam Bt at 1.25 m average depth. Interflow measured from two drains within an interception trench commenced after 131 and 208 mm of irrigation. Cumulative interflow equaledmore » 49% of applied water. Conservative tracer differences between the collection drains indicated differences in flow paths and storages within the plot. Event water fractions rose steadily throughout irrigation, peaking at 50% sixteen h after irrigation ceased. Data implied that tightly held water exchanged with event water throughout the experiment and a substantial portion of preevent water was released from the argillic layer. Surface-applied dye tracers bypassed the matrix, with peak concentrations measured shortly after flow commencement, indicating preferential network conductivities of 864–2240 mm/h, yet no macropore flow was observed. Near steady-state flow conditions indicated average conductivities of 460 mm/h and 2.5 mm/h for topsoils and the Bt horizon, respectively. Low ammonium and phosphorus concentrations in the interflow suggested rapid uptake or sorption, while higher nitrate concentrations suggested more conservative transport. Lastly, these results reveal how hydraulic conductivity variation and subsurface topographic complexity explain otherwise paradoxical solute and flow behaviors.« less

Washington Geothermal Play Fairway Analysis Data From Potential Field Studies

DOE Data Explorer

Anderson, Megan; Ritzinger, Brent; Glen, Jonathan; Schermerhorn, William

2017-12-20

A recent study which adapts play fairway analysis (PFA) methodology to assess geothermal potential was conducted at three locations (Mount Baker, Mount St. Helens seismic zone, and Wind River valley) along the Washington Cascade Range (Forson et al. 2017). Potential field (gravity and magnetic) methods which can detect subsurface contrasts in physical properties, provides a means for mapping and modeling subsurface geology and structure. As part of the WA-Cascade PFA project, we performed potential field studies by collecting high-resolution gravity and ground-magnetic data, and rock property measurements to (1) identify and constrain fault geometries (2) constrain subsurface lithologic distribution (3) study fault interactions (4) identify areas favorable to hydrothermal flow, and ultimately (5) guide future geothermal exploration at each location.

Evaluation of subsurface damage in concrete deck joints using impact echo method

DOE PAGES

Rickard, Larry; Choi, Wonchang

2016-01-01

Many factors can affect the overall performance and longevity of highway bridges, including the integrity of their deck joints. This study focuses on the evaluation of subsurface damage in deteriorated concrete deck joints, which includes the delamination and corrosion of the reinforcement. Impact echo and surface wave technology, mainly a portable seismic property analyzer (PSPA), were employed to evaluate the structural deficiency of concrete joints. Laboratory tests of core samples were conducted to verify the nondestructive test results. As a result, the primary advantage of the PSPA as a bridge assessment tool lies in its ability to assess the concrete’smore » modulus and to detect subsurface defects at a particular point simultaneously.« less

Searching for an Acidic Aquifer in the Rio Tinto Basin: First Geobiology Results of MARTE Project

NASA Technical Reports Server (NTRS)

Fernandez-Remolar, D. C.; Prieto-Ballesteros, O.; Stoker, C.

2004-01-01

Among the conceivable modern habitats to be explored for searching life on Mars are those potentially developed underground. Subsurface habitats are currently environments that, under certain physicochemical circumstances, have high thermal and hydrochemical stability [1, 2]. In planets like Mars lacking an atmospheric shield, such systems are obviously protected against radiation, which strongly alters the structure of biological macromolecules. Low porosity but fractured aquifers currently emplaced inside ancient volcano/sedimentary and hydrothermal systems act as excellent habitats [3] due to its thermal and geochemical properties. In these aquifers the temperature is controlled by a thermal balance between conduction and advection processes, which are driven by the rock composition, geological structure, water turnover of aquifers and heat generation from geothermal processes or chemical reactions [4]. Moreover, microbial communities based on chemolithotrophy can obtain energy by the oxidation of metallic ores that are currently associated to these environments. Such a community core may sustain a trophic web composed of non-autotrophic forms like heterotrophic bacteria, fungi and protozoa.

Nde of Frp Wrapped Columns Using Infrared Thermography

NASA Astrophysics Data System (ADS)

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

2008-02-01

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

Subsurface phosphorus transport through a no-till field in the semi arid Palouse region

NASA Astrophysics Data System (ADS)

Norby, J. C.; Brooks, E. S.; Strawn, D. G.

2017-12-01

Excess application of fertilizers containing nitrogen and phosphorus for farming use has led to ongoing water quality issues in the United States. When these nutrients leave agronomic systems, and enter water bodies in large quantities, algal bloom and eutrophication can occur. Extensive studies focusing on phosphorus as a pollutant from agronomic systems have been conducted in the many regions of the United States; however, there has been a lack of studies completed in the semiarid Palouse region of eastern Washington and western Idaho. The goal of this research study was to better understand how no-till farm management has altered soil P temporally and the current availability for off-site transport of P throughout an artificially drained catchment at the Cook Agronomy Farm in Pullman, WA. We also attempted to determine the processes responsible for subsurface flow of phosphorus, specifically through preferential flow pathways. Dissolved reactive P (DRP)concentrations of subsurface drainage from a artificial drain exceeded TMDL threshold concentrations during numerous seasonal high flow events over the two-year study time frame. Soil analyses show a highly variable distribution of water-extractable P across the sub-catchment area and initial results suggest a translocation of P species deeper into the soil profile after implementing no-till practices in 1998. We hypothesized that a greater network of macropores from lack of soil disturbance allow for preferential flow of nutrient-laden water deeper into the subsurface and to the artificial drain system. Simulated flow experiments on soil cores from the study site showed large-scale macropore development, extreme variability in soil conductivity, and high P adsorption potential for the soils, suggesting a disconnect between P movement through macropore soil and subsurface drainage water rich in DRP at the artificial drain line outlet.

Effects of hypobaric pressure on human skin: implications for cryogen spray cooling (part II).

PubMed

Aguilar, Guillermo; Franco, Walfre; Liu, Jie; Svaasand, Lars O; Nelson, J Stuart

2005-02-01

Clinical results have demonstrated that dark purple port wine stain (PWS) birthmarks respond favorably to laser induced photothermolysis after the first three to five treatments. Nevertheless, complete blanching is rarely achieved and the lesions stabilize at a red-pink color. In a feasibility study (Part I), we showed that local hypobaric pressure on PWS human skin prior to laser irradiation induced significant lesion blanching. The objective of the present study (Part II) is to investigate the effects of hypobaric pressures on the efficiency of cryogen spray cooling (CSC), a technique that assists laser therapy of PWS and other dermatoses. Experiments were carried out within a suction cup and vacuum chamber to study the effect of hypobaric pressure on the: (1) interaction of cryogen sprays with human skin; (2) spray atomization; and (3) thermal response of a model skin phantom. A high-speed camera was used to acquire digital images of spray impingement on in vivo human skin and spray cones generated at different hypobaric pressures. Subsequently, liquid cryogen was sprayed onto a skin phantom at atmospheric and 17, 34, 51, and 68 kPa (5, 10, 15, and 20 in Hg) hypobaric pressures. A fast-response temperature sensor measured sub-surface phantom temperature as a function of time. Measurements were used to solve an inverse heat conduction problem to calculate surface temperatures, heat flux, and overall heat extraction at the skin phantom surface. Under hypobaric pressures, cryogen spurts did not produce skin indentation and only minimal frost formation. Sprays also showed shorter jet lengths and better atomization. Lower minimum surface temperatures and higher overall heat extraction from skin phantoms were reached. The combined effects of hypobaric pressure result in more efficient cryogen evaporation that enhances heat extraction and, therefore, improves the epidermal protection provided by CSC. (c) 2005 Wiley-Liss, Inc.

Yucca Mountain Project Subsurface Facilities Design

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

A. Linden; R.S. Saunders; R.J. Boutin

2002-11-19

Four units of the Topopah Springs formation (volcanic tuff) are considered for the proposed repository: the upper lithophysal, the middle non-lithophysal, the lower lithophysal, and the lower non-lithophysal. Yucca Mountain was recently designated the site for a proposed repository to dispose of spent nuclear fuel and high-level radioactive waste. Work is proceeding to advance the design of subsurface facilities to accommodate emplacing waste packages in the proposed repository. This paper summarized recent progress in the design of subsurface layout of the proposed repository. The original Site Recommendation (SR) concept for the subsurface design located the repository largely within the lowermore » lithophysal zone (approximately 73%) of the Topopah The Site Recommendation characterized area suitable for emplacement consisted of the primary upper block, the lower block and the southern upper block extension. The primary upper block accommodated the mandated 70,000 metric tons of heavy metal (MTHM) at a 1.45 kW/m hear heat load. Based on further study of the Site Recommendation concept, the proposed repository siting area footprint was modified to make maximum use of available site characterization data, and thus, reduce uncertainties associated with performance assessment. As a result of this study, a modified repository footprint has been proposed and is presently being review for acceptance by the DOE. A panel design concept was developed to reduce overall costs and reduce the overall emplacement schedule. This concept provides flexibility to adjust the proposed repository subsurface layout with time, as it makes it unnecessary to ''commit'' to development of a large single panel at the earliest stages of construction. A description of the underground layout configuration and influencing factors that affect the layout configuration are discussed in the report.« less

Flow pathways in the Slapton Wood catchment using temperature as a tracer

NASA Astrophysics Data System (ADS)

Birkinshaw, Stephen J.; Webb, Bruce

2010-03-01

SummaryThis study investigates the potential of temperature as a tracer to provide insights into flow pathways. The approach couples fieldwork and modelling experiments for the Eastergrounds Hollow within the Slapton Wood catchment, South Devon, UK. Measurements in the Eastergrounds Hollow were carried out for soil temperature, spring temperature, and the stream temperature and use was made of an existing 1989-1991 data set for the entire Slapton Wood catchment. The predominant flow in this hollow is a result of subsurface stormflow, and previous work has suggested that the water flows vertically down through the soil and then subsurface stormflow occurs at the soil/bedrock interface where the water is deflected laterally. The depth of the subsurface stormflow was previously thought to be around 2.2 m. However, analysis of the new spring, stream and soil temperature data suggests a deeper pathway for the subsurface stormflow. Modelling of water flow and heat transport was carried out using SHETRAN and this was calibrated to reproduce the water flow in the entire Slapton Wood catchment and soil temperatures in the Eastergrounds Hollow. The model was tested for the entire Eastergrounds Hollow with two different soil depths. A depth of 2.2 m, based on previous knowledge, was unable to reproduce the Eastergrounds spring temperature. A depth of 3.7 m produced an excellent comparison between measured and simulated stream and spring temperatures in the Eastergrounds Hollow. This work suggests that the depth of the flow pathways that produce the subsurface stormflow are deeper than previously thought. It also provides a demonstration on the use of temperature as a tracer to understand flow pathways.

A multi-scale experimental and simulation approach for fractured subsurface systems

NASA Astrophysics Data System (ADS)

Viswanathan, H. S.; Carey, J. W.; Frash, L.; Karra, S.; Hyman, J.; Kang, Q.; Rougier, E.; Srinivasan, G.

2017-12-01

Fractured systems play an important role in numerous subsurface applications including hydraulic fracturing, carbon sequestration, geothermal energy and underground nuclear test detection. Fractures that range in scale from microns to meters and their structure control the behavior of these systems which provide over 85% of our energy and 50% of US drinking water. Determining the key mechanisms in subsurface fractured systems has been impeded due to the lack of sophisticated experimental methods to measure fracture aperture and connectivity, multiphase permeability, and chemical exchange capacities at the high temperature, pressure, and stresses present in the subsurface. In this study, we developed and use microfluidic and triaxial core flood experiments required to reveal the fundamental dynamics of fracture-fluid interactions. In addition we have developed high fidelity fracture propagation and discrete fracture network flow models to simulate these fractured systems. We also have developed reduced order models of these fracture simulators in order to conduct uncertainty quantification for these systems. We demonstrate an integrated experimental/modeling approach that allows for a comprehensive characterization of fractured systems and develop models that can be used to optimize the reservoir operating conditions over a range of subsurface conditions.

Evaluation of positron emission tomography as a method to visualize subsurface microbial processes

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

Kinsella K.; Schlyer D.; Kinsella, K.

2012-01-18

Positron emission tomography (PET) provides spatiotemporal monitoring in a nondestructive manner and has higher sensitivity and resolution relative to other tomographic methods. Therefore, this technology was evaluated for its application to monitor in situ subsurface bacterial activity. To date, however, it has not been used to monitor or image soil microbial processes. In this study, PET imaging was applied as a 'proof-of-principle' method to assess the feasibility of visualizing a radiotracer labeled subsurface bacterial strain (Rahnella sp. Y9602), previously isolated from uranium contaminated soils and shown to promote uranium phosphate precipitation. Soil columns packed with acid-purified simulated mineral soils weremore » seeded with 2-deoxy-2-[{sup 18}F]fluoro-d-glucose ({sup 18}FDG) labeled Rahnella sp. Y9602. The applicability of [{sup 18}F]fluoride ion as a tracer for measuring hydraulic conductivity and {sup 18}FDG as a tracer to identify subsurface metabolically active bacteria was successful in our soil column studies. Our findings indicate that positron-emitting isotopes can be utilized for studies aimed at elucidating subsurface microbiology and geochemical processes important in contaminant remediation.« less

A field evaluation of subsurface and surface runoff. II. Runoff processes

USGS Publications Warehouse

Pilgrim, D.H.; Huff, D.D.; Steele, T.D.

1978-01-01

Combined use of radioisotope tracer, flow rate, specific conductance and suspended-sediment measurements on a large field plot near Stanford, California, has provided more detailed information on surface and subsurface storm runoff processes than would be possible from any single approach used in isolation. Although the plot was surficially uniform, the runoff processes were shown to be grossly nonuniform, both spatially over the plot, and laterally and vertically within the soil. The three types of processes that have been suggested as sources of storm runoff (Horton-type surface runoff, saturated overland flow, and rapid subsurface throughflow) all occurred on the plot. The nonuniformity of the processes supports the partial- and variable-source area concepts. Subsurface storm runoff occurred in a saturated layer above the subsoil horizon, and short travel times resulted from flow through macropores rather than the soil matrix. Consideration of these observations would be necessary for physically realistic modeling of the storm runoff process. ?? 1978.

Reorientation of Sputnik Planitia implies a subsurface ocean on Pluto.

PubMed

Nimmo, F; Hamilton, D P; McKinnon, W B; Schenk, P M; Binzel, R P; Bierson, C J; Beyer, R A; Moore, J M; Stern, S A; Weaver, H A; Olkin, C B; Young, L A; Smith, K E

2016-12-01

The deep nitrogen-covered basin on Pluto, informally named Sputnik Planitia, is located very close to the longitude of Pluto's tidal axis and may be an impact feature, by analogy with other large basins in the Solar System. Reorientation of Sputnik Planitia arising from tidal and rotational torques can explain the basin's present-day location, but requires the feature to be a positive gravity anomaly, despite its negative topography. Here we argue that if Sputnik Planitia did indeed form as a result of an impact and if Pluto possesses a subsurface ocean, the required positive gravity anomaly would naturally result because of shell thinning and ocean uplift, followed by later modest nitrogen deposition. Without a subsurface ocean, a positive gravity anomaly requires an implausibly thick nitrogen layer (exceeding 40 kilometres). To prolong the lifetime of such a subsurface ocean to the present day and to maintain ocean uplift, a rigid, conductive water-ice shell is required. Because nitrogen deposition is latitude-dependent, nitrogen loading and reorientation may have exhibited complex feedbacks.

Reorientation of Sputnik Planitia implies a subsurface ocean on Pluto

NASA Astrophysics Data System (ADS)

Nimmo, F.; Hamilton, D. P.; McKinnon, W. B.; Schenk, P. M.; Binzel, R. P.; Bierson, C. J.; Beyer, R. A.; Moore, J. M.; Stern, S. A.; Weaver, H. A.; Olkin, C. B.; Young, L. A.; Smith, K. E.; Moore, J. M.; McKinnon, W. B.; Spencer, J. R.; Beyer, R.; Binzel, R. P.; Buie, M.; Buratti, B.; Cheng, A.; Cruikshank, D.; Ore, C. Dalle; Earle, A.; Gladstone, R.; Grundy, W.; Howard, A. D.; Lauer, T.; Linscott, I.; Nimmo, F.; Parker, J.; Porter, S.; Reitsema, H.; Reuter, D.; Roberts, J. H.; Robbins, S.; Schenk, P. M.; Showalter, M.; Singer, K.; Strobel, D.; Summers, M.; Tyler, L.; White, O. L.; Umurhan, O. M.; Banks, M.; Barnouin, O.; Bray, V.; Carcich, B.; Chaikin, A.; Chavez, C.; Conrad, C.; Hamilton, D. P.; Howett, C.; Hofgartner, J.; Kammer, J.; Lisse, C.; Marcotte, A.; Parker, A.; Retherford, K.; Saina, M.; Runyon, K.; Schindhelm, E.; Stansberry, J.; Steffl, A.; Stryk, T.; Throop, H.; Tsang, C.; Verbiscer, A.; Winters, H.; Zangari, A.; Stern, S. A.; Weaver, H. A.; Olkin, C. B.; Young, L. A.; Smith, K. E.

2016-12-01

The deep nitrogen-covered basin on Pluto, informally named Sputnik Planitia, is located very close to the longitude of Pluto’s tidal axis and may be an impact feature, by analogy with other large basins in the Solar System. Reorientation of Sputnik Planitia arising from tidal and rotational torques can explain the basin’s present-day location, but requires the feature to be a positive gravity anomaly, despite its negative topography. Here we argue that if Sputnik Planitia did indeed form as a result of an impact and if Pluto possesses a subsurface ocean, the required positive gravity anomaly would naturally result because of shell thinning and ocean uplift, followed by later modest nitrogen deposition. Without a subsurface ocean, a positive gravity anomaly requires an implausibly thick nitrogen layer (exceeding 40 kilometres). To prolong the lifetime of such a subsurface ocean to the present day and to maintain ocean uplift, a rigid, conductive water-ice shell is required. Because nitrogen deposition is latitude-dependent, nitrogen loading and reorientation may have exhibited complex feedbacks.

Ground-penetrating radar and electromagnetic surveys at the Monroe Crossroads battlefield site, Fort Bragg, North Carolina

USGS Publications Warehouse

Kessler, Richard; Strain, R.E.; Marlowe, J. I.; Currin, K.B.

1996-01-01

A ground-penetrating radar survey was conducted at the Monroe Crossroads Battlefield site at Fort Bragg, North Carolina, to determine possible locations of subsurface archaeological features. An electromagnetic survey also was conducted at the site to verify and augment the ground-penetrating radar data. The surveys were conducted over a 67,200-square-foot grid with a grid point spacing of 20 feet. During the ground-penetrating radar survey, 87 subsurface anomalies were detected based on visual inspection of the field records. These anomalies were flagged in the field as they appeared on the ground-penetrating radar records and were located by a land survey. The electromagnetic survey produced two significant readings at ground-penetrating radar anomaly locations. The National Park Service excavated 44 of the 87 anomaly locations at the Civil War battlefield site. Four of these excavations produced significant archaeological features, including one at an abandoned well.

Permittivity and conductivity parameter estimations using full waveform inversion

NASA Astrophysics Data System (ADS)

Serrano, Jheyston O.; Ramirez, Ana B.; Abreo, Sergio A.; Sadler, Brian M.

2018-04-01

Full waveform inversion of Ground Penetrating Radar (GPR) data is a promising strategy to estimate quantitative characteristics of the subsurface such as permittivity and conductivity. In this paper, we propose a methodology that uses Full Waveform Inversion (FWI) in time domain of 2D GPR data to obtain highly resolved images of the permittivity and conductivity parameters of the subsurface. FWI is an iterative method that requires a cost function to measure the misfit between observed and modeled data, a wave propagator to compute the modeled data and an initial velocity model that is updated at each iteration until an acceptable decrease of the cost function is reached. The use of FWI with GPR are expensive computationally because it is based on the computation of the electromagnetic full wave propagation. Also, the commercially available acquisition systems use only one transmitter and one receiver antenna at zero offset, requiring a large number of shots to scan a single line.

Three-dimensional modelling and geothermal process simulation

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

Burns, K.L.

1990-01-01

The subsurface geological model or 3-D GIS is constructed from three kinds of objects, which are a lithotope (in boundary representation), a number of fault systems, and volumetric textures (vector fields). The chief task of the model is to yield an estimate of the conductance tensors (fluid permeability and thermal conductivity) throughout an array of voxels. This is input as material properties to a FEHM numerical physical process model. The main task of the FEHM process model is to distinguish regions of convective from regions of conductive heat flow, and to estimate the fluid phase, pressure and flow paths. Themore » temperature, geochemical, and seismic data provide the physical constraints on the process. The conductance tensors in the Franciscan Complex are to be derived by the addition of two components. The isotropic component is a stochastic spatial variable due to disruption of lithologies in melange. The deviatoric component is deterministic, due to smoothness and continuity in the textural vector fields. This decomposition probably also applies to the engineering hydrogeological properties of shallow terrestrial fluvial systems. However there are differences in quantity. The isotropic component is much more variable in the Franciscan, to the point where volumetric averages are misleading, and it may be necessary to select that component from several, discrete possible states. The deviatoric component is interpolated using a textural vector field. The Franciscan field is much more complicated, and contains internal singularities. 27 refs., 10 figs.« less

Geophysical characterization of fractured bedrock at Site 8, former Pease Air Force Base, Newington, New Hampshire

USGS Publications Warehouse

Mack, Thomas J.; Degnan, James R.

2003-01-01

Borehole-geophysical logs collected from eight wells and direct-current resistivity data from three survey lines were analyzed to characterize the fractured bedrock and identify transmissive fractures beneath the former Pease Air Force Base, Newington, N.H. The following logs were used: caliper, fluid temperature and conductivity, natural gamma radiation, electromagnetic conductivity, optical and acoustic televiewer, and heat-pulse flowmeter. The logs indicate several foliation and fracture trends in the bedrock. Two fracture-correlated lineaments trending 28? and 29?, identified with low-altitude aerial photography, are coincident with the dominant structural trend. The eight boreholes logged at Site 8 generally have few fractures and have yields ranging from 0 to 40 gallons per minute. The fractures that probably resulted in high well yields (20?40 gallons per minute) strike northeast-southwest or by the right hand rule, have an orientation of 215?, 47?, and 51?. Two-dimensional direct-current resistivity methods were used to collect detailed subsurface information about the overburden, bedrock-fracture zone depths, and apparent-dip directions. Analysis of data inversions from data collected with dipole-dipole and Schlumberger arrays indicated electrically conductive zones in the bedrock that are probably caused by fractured rock. These zones are coincident with extensions of fracture-correlated lineaments. The fracture-correlated lineaments and geophysical-survey results indicate a possible northeast-southwest anisotropy to the fractured rock.

Uncertainty in the modelling of spatial and temporal patterns of shallow groundwater flow paths: The role of geological and hydrological site information

NASA Astrophysics Data System (ADS)

Woodward, Simon J. R.; Wöhling, Thomas; Stenger, Roland

2016-03-01

Understanding the hydrological and hydrogeochemical responses of hillslopes and other small scale groundwater systems requires mapping the velocity and direction of groundwater flow relative to the controlling subsurface material features. Since point observations of subsurface materials and groundwater head are often the basis for modelling these complex, dynamic, three-dimensional systems, considerable uncertainties are inevitable, but are rarely assessed. This study explored whether piezometric head data measured at high spatial and temporal resolution over six years at a hillslope research site provided sufficient information to determine the flow paths that transfer nitrate leached from the soil zone through the shallow saturated zone into a nearby wetland and stream. Transient groundwater flow paths were modelled using MODFLOW and MODPATH, with spatial patterns of hydraulic conductivity in the three material layers at the site being estimated by regularised pilot point calibration using PEST, constrained by slug test estimates of saturated hydraulic conductivity at several locations. Subsequent Null Space Monte Carlo uncertainty analysis showed that this data was not sufficient to definitively determine the spatial pattern of hydraulic conductivity at the site, although modelled water table dynamics matched the measured heads with acceptable accuracy in space and time. Particle tracking analysis predicted that the saturated flow direction was similar throughout the year as the water table rose and fell, but was not aligned with either the ground surface or subsurface material contours; indeed the subsurface material layers, having relatively similar hydraulic properties, appeared to have little effect on saturated water flow at the site. Flow path uncertainty analysis showed that, while accurate flow path direction or velocity could not be determined on the basis of the available head and slug test data alone, the origin of well water samples relative to the material layers and site contour could still be broadly deduced. This study highlights both the challenge of collecting suitably informative field data with which to characterise subsurface hydrology, and the power of modern calibration and uncertainty modelling techniques to assess flow path uncertainty in hillslopes and other small scale systems.

Efficient high-dimensional characterization of conductivity in a sand box using massive MRI-imaged concentration data

NASA Astrophysics Data System (ADS)

Lee, J. H.; Yoon, H.; Kitanidis, P. K.; Werth, C. J.; Valocchi, A. J.

2015-12-01

Characterizing subsurface properties, particularly hydraulic conductivity, is crucial for reliable and cost-effective groundwater supply management, contaminant remediation, and emerging deep subsurface activities such as geologic carbon storage and unconventional resources recovery. With recent advances in sensor technology, a large volume of hydro-geophysical and chemical data can be obtained to achieve high-resolution images of subsurface properties, which can be used for accurate subsurface flow and reactive transport predictions. However, subsurface characterization with a plethora of information requires high, often prohibitive, computational costs associated with "big data" processing and large-scale numerical simulations. As a result, traditional inversion techniques are not well-suited for problems that require coupled multi-physics simulation models with massive data. In this work, we apply a scalable inversion method called Principal Component Geostatistical Approach (PCGA) for characterizing heterogeneous hydraulic conductivity (K) distribution in a 3-D sand box. The PCGA is a Jacobian-free geostatistical inversion approach that uses the leading principal components of the prior information to reduce computational costs, sometimes dramatically, and can be easily linked with any simulation software. Sequential images of transient tracer concentrations in the sand box were obtained using magnetic resonance imaging (MRI) technique, resulting in 6 million tracer-concentration data [Yoon et. al., 2008]. Since each individual tracer observation has little information on the K distribution, the dimension of the data was reduced using temporal moments and discrete cosine transform (DCT). Consequently, 100,000 unknown K values consistent with the scale of MRI data (at a scale of 0.25^3 cm^3) were estimated by matching temporal moments and DCT coefficients of the original tracer data. Estimated K fields are close to the true K field, and even small-scale variability of the sand box was captured to highlight high K connectivity and contrasts between low and high K zones. Total number of 1,000 MODFLOW and MT3DMS simulations were required to obtain final estimates and corresponding estimation uncertainty, showing the efficiency and effectiveness of our method.

Characterizing preferential groundwater discharge through boils using temperature

NASA Astrophysics Data System (ADS)

Vandenbohede, A.; de Louw, P. G. B.; Doornenbal, P. J.

2014-03-01

In The Netherlands, preferential groundwater discharge trough boils is a key process in the salinization of deep polders. Previous work showed that boils also influence the temperature in the subsurface and of surface water. This paper elaborates on this process combining field observations with numerical modeling. As is the case for salinity, a distinct anomaly in the subsurface and surface water temperature can be attributed to boils. Lines of equal temperature are distorted towards the boil, which can be considered as an upconing of the temperature profile by analogy of the upconing of a fresh-saltwater interface. The zone of this distortion is limited to the immediate vicinity of the boil, being about 5 m in the aquitard which holds the boil's conduit, or maximum a few dozens of meters in the underlying aquifer. In the aquitard, heat transport is conduction dominated whereas this is convection dominated in the aquifer. The temperature anomaly differs from the salinity anomaly by the smaller radius of influence and faster time to reach a new steady-state of the former. Boils discharge water with a temperature equal to the mean groundwater temperature. This influences the yearly and diurnal variation of ditch water temperature in the immediate vicinity of the boil importantly but also the temperature in the downstream direction. Temporary nature of the boil (e.g. stability of the conduit, discharge rate), uncertainty on the 3D construction of the conduit and heterogeneity of the subsoil make it unlikely that temperature measurements can be interpreted further than a qualitative level.

Multi-method, multi-scale geophysical observations in the Obsidian Pool Thermal Area, Yellowstone National Park

NASA Astrophysics Data System (ADS)

Holbrook, W. S.; Carr, B.; Pasquet, S.; Sims, K. W. W.; Dickey, K.

2016-12-01

Despite the prominence of Yellowstone as the world's most active hydrothermal province, relatively little is known about the plumbing systems that link deeper hydrothermal fluids to the charismatic hot springs, geysers and mud pots at the surface. We present the results of a multi-method, multi-scale geophysical investigation of the Obsidian Pool Thermal Area (OPTA) in Yellowstone National Park. OPTA hosts acid-sulfate hot springs and mud pots with relatively low pH. We present the results of seismic refraction, electrical resistivity, time-domain EM (TEM), soil conductivity meter (EMI), and GPR data acquired in July 2016. There is a strong contrast in physical properties in the upper 50 m of the subsurface between the low-lying hydrothermal area and surrounding hills: the hydrothermal area has much lower seismic velocities ( 1 km/s vs 3 km/s) and electrical resistivity ( 20 ohm-m vs 300 ohm-m). A prominent zone of very low resistivity (<10 ohm-m) exists at about 20 m depth beneath all hydrothermal features. Poisson's ratio, calculated from P-wave refraction tomography and surface wave inversions, shows low values beneath the "frying pan," where gas is emerging in small fumaroles, suggesting that Poisson's ratio is an effective "gas detector" in hydrothermal areas. Near-surface resistivity mapped from EMI shows a strong correlation with hydrothermal areas previously mapped by heat flow, with areas of high heat flow generally having low resistivity near the surface. Two exceptions are (1) the "frying pan," which shows a central area of high resistivity (corresponding to escaping gas) surrounding by a halo of low resistivity, and (2) a broad area of low resistivity connecting the hydrothermal centers to the lake, which may be clay deposits. TEM data penetrate up to 200 m in depth and suggest that a reservoir of hydrothermal fluids may underlie the entire area, including beneath the forested hills, at depths greater than 100 m, but that they rise toward the surface in a 100-m-wide area just west of the frying pan. Our results show that synoptic, multi-scale geophysical measurements can place important constraints on the subsurface pathways of hydrothermal waters and gas.

Enhanced groundwater recharge rates and altered recharge sensitivity to climate variability through subsurface heterogeneity

PubMed Central

Hartmann, Andreas; Gleeson, Tom; Wagener, Thorsten

2017-01-01

Our environment is heterogeneous. In hydrological sciences, the heterogeneity of subsurface properties, such as hydraulic conductivities or porosities, exerts an important control on water balance. This notably includes groundwater recharge, which is an important variable for efficient and sustainable groundwater resources management. Current large-scale hydrological models do not adequately consider this subsurface heterogeneity. Here we show that regions with strong subsurface heterogeneity have enhanced present and future recharge rates due to a different sensitivity of recharge to climate variability compared with regions with homogeneous subsurface properties. Our study domain comprises the carbonate rock regions of Europe, Northern Africa, and the Middle East, which cover ∼25% of the total land area. We compare the simulations of two large-scale hydrological models, one of them accounting for subsurface heterogeneity. Carbonate rock regions strongly exhibit “karstification,” which is known to produce particularly strong subsurface heterogeneity. Aquifers from these regions contribute up to half of the drinking water supply for some European countries. Our results suggest that water management for these regions cannot rely on most of the presently available projections of groundwater recharge because spatially variable storages and spatial concentration of recharge result in actual recharge rates that are up to four times larger for present conditions and changes up to five times larger for potential future conditions than previously estimated. These differences in recharge rates for strongly heterogeneous regions suggest a need for groundwater management strategies that are adapted to the fast transit of water from the surface to the aquifers. PMID:28242703

Enhanced Groundwater Recharge Rates and Altered Recharge Sensitivity to Climate Variability Through Subsurface Heterogeneity

NASA Technical Reports Server (NTRS)

Hartmann, Andreas; Gleeson, Tom; Wada, Yoshihide; Wagener, Thorsten

2017-01-01

Our environment is heterogeneous. In hydrological sciences, the heterogeneity of subsurface properties, such as hydraulic conductivities or porosities, exerts an important control on water balance. This notably includes groundwater recharge, which is an important variable for efficient and sustainable groundwater resources management. Current large-scale hydrological models do not adequately consider this subsurface heterogeneity. Here we show that regions with strong subsurface heterogeneity have enhanced present and future recharge rates due to a different sensitivity of recharge to climate variability compared with regions with homogeneous subsurface properties. Our study domain comprises the carbonate rock regions of Europe, Northern Africa, and the Middle East, which cover 25 of the total land area. We compare the simulations of two large-scale hydrological models, one of them accounting for subsurface heterogeneity. Carbonate rock regions strongly exhibit karstification, which is known to produce particularly strong subsurface heterogeneity. Aquifers from these regions contribute up to half of the drinking water supply for some European countries. Our results suggest that water management for these regions cannot rely on most of the presently available projections of groundwater recharge because spatially variable storages and spatial concentration of recharge result in actual recharge rates that are up to four times larger for present conditions and changes up to five times larger for potential future conditions than previously estimated. These differences in recharge rates for strongly heterogeneous regions suggest a need for groundwater management strategies that are adapted to the fast transit of water from the surface to the aquifers.

Vanadium Respiration by Geobacter metallireducens: Novel Strategy for In Situ Removal of Vanadium from Groundwater

PubMed Central

Ortiz-Bernad, Irene; Anderson, Robert T.; Vrionis, Helen A.; Lovley, Derek R.

2004-01-01

Vanadium can be an important contaminant in groundwaters impacted by mining activities. In order to determine if microorganisms of the Geobacteraceae, the predominant dissimilatory metal reducers in many subsurface environments, were capable of reducing vanadium(V), Geobacter metallireducens was inoculated into a medium in which acetate was the electron donor and vanadium(V) was the sole electron acceptor. Reduction of vanadium(V) resulted in the production of vanadium(IV), which subsequently precipitated. Reduction of vanadium(V) was associated with cell growth with a generation time of 15 h. No vanadium(V) was reduced and no precipitate was formed in heat-killed or abiotic controls. Acetate was the most effective of all the electron donors evaluated. When acetate was injected into the subsurface to enhance the growth and activity of Geobacteraceae in an aquifer contaminated with uranium and vanadium, vanadium was removed from the groundwater even more effectively than uranium. These studies demonstrate that G. metallireducens can grow via vanadium(V) respiration and that stimulating the activity of Geobacteraceae, and hence vanadium(V) reduction, can be an effective strategy for in situ immobilization of vanadium in contaminated subsurface environments. PMID:15128571

Evaluation of Geothermal and Natural Gas Resources Beneath Camp Dawson and Opportunities for Deep Direct Use of Geothermal Energy or Natural Gas for Heat and Electricity Production; NETL-TRS-8-2017; NETL Technical Report Series; U.S. Department of Energy, National Energy Technology Laboratory: Morgantown, WV, 2017; p 148.

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

Means, Ken; Muring, Timothy M.; Sams, Neal W.

NETL has reviewed available information and evaluated the deep geothermal and natural gas resources located beneath the Camp Dawson National Guard Training Center in West Virginia. This facility is located in the northeastern portion of the state in Preston County, near the town of Kingwood. This study reviews options for the onsite drilling of wells for the production of geothermal heat or natural gas, as well as the utilization of these resources for on-site power and heating needs. Resources of potential interest are at subsurface depths between 7,000 feet and 15,000 feet.

Big Jump of Record Warm Global Mean Surface Temperature in 2014-2016 Related to Unusually Large Oceanic Heat Releases

NASA Astrophysics Data System (ADS)

Yin, Jianjun; Overpeck, Jonathan; Peyser, Cheryl; Stouffer, Ronald

2018-01-01

A 0.24°C jump of record warm global mean surface temperature (GMST) over the past three consecutive record-breaking years (2014-2016) was highly unusual and largely a consequence of an El Niño that released unusually large amounts of ocean heat from the subsurface layer of the northwestern tropical Pacific. This heat had built up since the 1990s mainly due to greenhouse-gas (GHG) forcing and possible remote oceanic effects. Model simulations and projections suggest that the fundamental cause, and robust predictor of large record-breaking events of GMST in the 21st century, is GHG forcing rather than internal climate variability alone. Such events will increase in frequency, magnitude, and duration, as well as impact, in the future unless GHG forcing is reduced.

Exchange of Groundwater and Surface-Water Mediated by Permafrost Response to Seasonal and Long Term Air Temperature Variation

USGS Publications Warehouse

Ge, Shemin; McKenzie, Jeffrey; Voss, Clifford; Wu, Qingbai

2011-01-01

Permafrost dynamics impact hydrologic cycle processes by promoting or impeding groundwater and surface water exchange. Under seasonal and decadal air temperature variations, permafrost temperature changes control the exchanges between groundwater and surface water. A coupled heat transport and groundwater flow model, SUTRA, was modified to simulate groundwater flow and heat transport in the subsurface containing permafrost. The northern central Tibet Plateau was used as an example of model application. Modeling results show that in a yearly cycle, groundwater flow occurs in the active layer from May to October. Maximum groundwater discharge to the surface lags the maximum subsurface temperature by two months. Under an increasing air temperature scenario of 3?C per 100 years, over the initial 40-year period, the active layer thickness can increase by three-fold. Annual groundwater discharge to the surface can experience a similar three-fold increase in the same period. An implication of these modeling results is that with increased warming there will be more groundwater flow in the active layer and therefore increased groundwater discharge to rivers. However, this finding only holds if sufficient upgradient water is available to replenish the increased discharge. Otherwise, there will be an overall lowering of the water table in the recharge portion of the catchment.

Water World

NASA Image and Video Library

2015-11-30

Although Enceladus and Saturn's rings are largely made up of water ice, they show very different characteristics. The small ring particles are too tiny to retain internal heat and have no way to get warm, so they are frozen and geologically dead. Enceladus, on the other hand, is subject to forces that heat its interior to this very day. This results in its famous south polar water jets, which are just visible above the moon's dark, southern limb, along with a sub-surface ocean. Recent work by Cassini scientists suggests that Enceladus (313 miles or 504 kilometers across) has a global ocean of liquid water under its surface. This discovery increases scientists' interest in Enceladus and the quest to understand the role of water in the development of life in the solar system. (For more on the sub-surface ocean, see this story.) This view looks toward the unilluminated side of the rings from about 0.3 degrees below the ring plane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on July 29, 2015. The view was acquired at a distance of approximately 630,000 miles (1.0 million kilometers) from Enceladus and at a Sun-Enceladus-spacecraft, or phase angle of 155 degrees. Image scale is 4 miles (6 kilometers) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA18343

Sedimentary silicon isotope indicates the Kuroshio subsurface upwelling in the East China Sea

NASA Astrophysics Data System (ADS)

Zhao, Y.; Yang, S.; Su, N.

2017-12-01

The Kuroshio as the western boundary current of the North Pacific subtropical circulation, originates from east of the Philippine Islands, and flows northeastward along the eastern coast of Taiwan. It's subsurface water intrudes the East China Sea (ECS) and forms a typical upwelling on the inner shelf, which may play an important role in the material and heat transport, biogeochemical process and marine ecosystem of the ECS.To date, most previous studies on the Kuroshio subsurface upwelling focuse on the seasonal and interannual variations, and few researches touch on the upwelling evolution in the geologic past. In this study, eight short sediment cores were taken along the ECS inner shelf (upwelling area), which allow us to reconstruct the upwelling history over the last several hundred years. Although conventional indexes of oceanographic changes, such as salinity, temperature and hydrogen and oxygen isotope, provide valuable constraints on the modern oceanic circulation and water mass movements, how to reconstruct them from geologic records is always a challenging work. In this contribution, we present the data of stable silicon isotope, biogenic opal, diatom assemblages, element geochemistry and stable carbon and nitrogen isotopes of these core sediments, and aim to decipher the Kuroshio subsurface upwelling history on the ECS shelf. We will also illustrate the difference in δ30Si signals between small (<30 um) and large (>150 um) diatom fractions, and test whether it is an effective indicator for paleo-upwelling intensity.

Isolated molecular dopants in pentacene observed by scanning tunneling microscopy

NASA Astrophysics Data System (ADS)

Ha, Sieu D.; Kahn, Antoine

2009-11-01

Doping is essential to the control of electronic structure and conductivity of semiconductor materials. Whereas doping of inorganic semiconductors is well established, doping of organic molecular semiconductors is still relatively poorly understood. Using scanning tunneling microscopy, we investigate, at the molecular scale, surface and subsurface tetrafluoro-tetracyanoquinodimethane p -dopants in the prototypical molecular semiconductor pentacene. Surface dopants diffuse to pentacene vacancies and appear as negatively charged centers, consistent with the standard picture of an ionized acceptor. Subsurface dopants, however, have the effect of a positive charge, evidence that the donated hole is localized by the parent acceptor counterion, in contrast to the model of doping in inorganic semiconductors. Scanning tunneling spectroscopy shows that the electron potential energy is locally lowered near a subsurface dopant feature, in agreement with the localized hole model.

Sorting Out the Ocean Crust Deep Biosphere with Single Cell Omics Approaches

NASA Astrophysics Data System (ADS)

Orcutt, B.; D'Angelo, T.; Goordial, J.; Jones, R. M.; Carr, S. A.

2017-12-01

Although oceanic crust comprises a large habitat for subsurface life, the structure, function, and dynamics of microbial communities living on rocks in the subsurface are poorly understood. Single cell level approaches can overcome limitations of low biomass in subsurface systems. Coupled with incubation experiments with amino acid orthologs, single cell level sorting can reveal high resolution information about identity, functional potential, and growth. Leveraging collaboration with the Single Cell Genomics Center and the Facility for Aquatic Cytometry at Bigelow Laboratory, we present recent results from single cell level sorting and -omics sequencing from several crustal environments, including the Atlantis Massif and the Juan de Fuca Ridge flank. We will also highlight new experiments conducted with samples recovered from the flank of the Mid-Atlantic Ridge.

Axial flow heat exchanger devices and methods for heat transfer using axial flow devices

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

Koplow, Jeffrey P.

Systems and methods described herein are directed to rotary heat exchangers configured to transfer heat to a heat transfer medium flowing in substantially axial direction within the heat exchangers. Exemplary heat exchangers include a heat conducting structure which is configured to be in thermal contact with a thermal load or a thermal sink, and a heat transfer structure rotatably coupled to the heat conducting structure to form a gap region between the heat conducting structure and the heat transfer structure, the heat transfer structure being configured to rotate during operation of the device. In example devices heat may be transferredmore » across the gap region from a heated axial flow of the heat transfer medium to a cool stationary heat conducting structure, or from a heated stationary conducting structure to a cool axial flow of the heat transfer medium.« less

On thermal properties of hard rocks as a host environment of an underground thermal energy storage

NASA Astrophysics Data System (ADS)

Novakova, L.; Hladky, R.; Broz, M.; Novak, P.; Lachman, V.; Sosna, K.; Zaruba, J.; Metelkova, Z.; Najser, J.

2013-12-01

With increasing focus on environmentally friendly technologies waste heat recycling became an important issue. Under certain circumstances subsurface environment could be utilized to accommodate relatively large quantity of heat. Industrial waste heat produced during warm months can be stored in an underground thermal energy storage (UTES) and used when needed. It is however a complex task to set up a sustainable UTES for industrial scale. Number of parameters has to be studied and evaluated by means of thermohydromechanical and chemical coupling (THMC) before any UTES construction. Thermal characteristics of various rocks and its stability under thermal loading are amongst the most essential. In the Czech Republic study two complementary projects THMC processes during an UTES operation. The RESEN project (www.resen.cz) employs laboratory tests and experiments to characterise thermal properties of hard rocks in the Bohemian Massif. Aim of the project is to point out the most suitable rock environment in the Bohemian Massif for moderate to ultra-high temperature UTES construction (Sanyal, 2005). The VITA project (www.geology.cz/mokrsko) studies THM coupling in non-electrical temperature UTES using long term in-situ experiment. In both projects thermal properties of rocks were studied. Thermal conductivity and capacity were measured on rock samples. In addition an influence of increasing temperature and moisture content was considered. Ten hard rocks were investigated. The set included two sandstones, two ignibrites, a melaphyr, a syenite, two granites, a gneiss and a serpentinite. For each rock there were measured thermal conductivity and capacity of at least 54 dried samples. Subsequently, the samples were heated up to 380°C in 8 hours and left to cool down. Thermal characteristics were measured during the heating period and after the sample reached room temperature. Heating and cooling cycle was repeated 7 to 10 times to evaluate possible UTES-like degradation of the studied rocks. The studies revealed thermal loading caused rapid decrease of thermal conductivity of a rock. The decrease of up to 30.6% was observed in sandstones. Reduction up to 16% was found in the granite, 12.3% in the syenite, 12.1% in the gneiss, 10.1% in the serpentinite, 8.1% in the melaphyr and 5.9 - 6.5% in ignimbites. Thermal loading initiated insignificant decrement of the thermal capacity. The capacity loss was usually less than 2%. Increasing content of water caused increase in the measured thermal characteristics. Saturated melaphyr showed 29% higher conductivity and 17.8% higher capacity comparing to the dried one. In the ignibrites there was found growth up to 23.5% in the thermal conductivity and 14.9% in the capacity, 12.1-17.6% and 4.5-5.9% in granites, 9.1% and 11.1% in the serpetinite, 7.9% and 7.9% in the gneiss and 1.2% and 3.4% in the syenite. This work was funded by the Technology Agency of the CR (TA01020348) and Ministry of Industry and trade of the CR (FR-TI3/325). Reference Sanyal, S.K., 2005. Classification of geothermal systems - a possible scheme, Proceedings, 30th Workshop on Geothermal Reservoir Engineering, Stanford University, Stanford, California, p. 85-88.

Method for Implementing Subsurface Solid Derived Concentration Guideline Levels (DCGL) - 12331

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

Lively, J.W.

2012-07-01

The U.S. Nuclear Regulatory Commission (NRC) and other federal agencies currently approve the Multi-Agency Radiation Site Survey and Investigation Manual (MARSSIM) as guidance for licensees who are conducting final radiological status surveys in support of decommissioning. MARSSIM provides a method to demonstrate compliance with the applicable regulation by comparing residual radioactivity in surface soils with derived concentration guideline levels (DCGLs), but specifically discounts its applicability to subsurface soils. Many sites and facilities undergoing decommissioning contain subsurface soils that are potentially impacted by radiological constituents. In the absence of specific guidance designed to address the derivation of subsurface soil DCGLs andmore » compliance demonstration, decommissioning facilities have attempted to apply DCGLs and final status survey techniques designed specifically for surface soils to subsurface soils. The decision to apply surface soil limits and surface soil compliance metrics to subsurface soils typically results in significant over-excavation with associated cost escalation. MACTEC, Inc. has developed the overarching concepts and principles found in recent NRC decommissioning guidance in NUREG 1757 to establish a functional method to derive dose-based subsurface soil DCGLs. The subsurface soil method developed by MACTEC also establishes a rigorous set of criterion-based data evaluation metrics (with analogs to the MARSSIM methodology) that can be used to demonstrate compliance with the developed subsurface soil DCGLs. The method establishes a continuum of volume factors that relate the size and depth of a volume of subsurface soil having elevated concentrations of residual radioactivity with its ability to produce dose. The method integrates the subsurface soil sampling regime with the derivation of the subsurface soil DCGL such that a self-regulating optimization is naturally sought by both the responsible party and regulator. This paper describes the concepts and basis used by MACTEC to develop the dose-based subsurface soil DCGL method. The paper will show how MACTEC's method can be used to demonstrate that higher concentrations of residual radioactivity in subsurface soils (as compared with surface soils) can meet the NRC's dose-based regulations. MACTEC's method has been used successfully to obtain the NRC's radiological release at a site with known radiological impacts to subsurface soils exceeding the surface soil DCGL, saving both time and cost. Having considered the current NRC guidance for consideration of residual radioactivity in subsurface soils during decommissioning, MACTEC has developed a technically based approach to the derivation of and demonstration of compliance with subsurface soil DCGLs for radionuclides. In fact, the process uses the already accepted concepts and metrics approved for surface soils as the foundation for deriving scaling factors used to calculate subsurface soil DCGLs that are at least equally protective of the decommissioning annual dose standard. Each of the elements identified for consideration in the current NRC guidance is addressed in this proposed method. Additionally, there is considerable conservatism built into the assumptions and techniques used to arrive at subsurface soil scaling factors and DCGLs. The degree of conservatism embodied in the approach used is such that risk managers and decision makers approving and using subsurface soil DCGLs derived in accordance with this method can be confident that the future exposures will be well below permissible and safe levels. The technical basis for the method can be applied to a broad variety of sites with residual radioactivity in subsurface soils. Given the costly nature of soil surveys, excavation, and disposal of soils as low-level radioactive waste, MACTEC's method for deriving and demonstrating compliance with subsurface soil DCGLs offers the possibility of significant cost savings over the traditional approach of applying surface soil DCGLs to subsurface soils. Furthermore, while yet untested, MACTEC believes that the concepts and methods embodied in this approach could readily be applied to other types of contamination found in subsurface soils. (author)« less

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

NASA Astrophysics Data System (ADS)

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

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

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

NASA Astrophysics Data System (ADS)

Martinez, I. A.; Eisenmann, D.

2012-12-01

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

Isolated ecosystems on supercooled scree slopes in subalpine environments - interaction between permafrost, soil and vegetation

NASA Astrophysics Data System (ADS)

Schwindt, Daniel; Kozák, Johanna-Luise; Kohlpaintner, Michael

2017-04-01

In the central European Alps, permafrost can be expected in altitudes above 2300 m a.s.l., where mean annual air temperatures are below -1°C. However, attributed to the thermally induced "chimney effect", isolated permafrost lenses can be found in scree slopes far below the timberline where mean annual air temperature is positive. Usually the supercooled subsurface appears as lenses at the foot of talus slopes, covered by a thick layer of organic material and a unique vegetation composition most obviously characterized by dwarf grown trees ("Hexenwäldli") and azonal plant species. The fact that mean annual air temperature is positive and therefore can be excluded as a driving factor makes these sites unique for studying interdependencies between a supercooled subsurface, plant adaptation and vegetation sociology as well as the soil development. Three study sites in the Swiss Alps, differing in altitude and substrate (granite, dolomite, limestone) were investigated. Studies covered the permafrost-affected central parts of the slope as well as the surrounding areas. For characterizing distribution and temporal variability of ground ice geophysical methods were applied (electrical resistivity- and seismic refraction tomography). Temperature data loggers were used for monitoring the thermal regime (air-, surface- and soil temperatures). Chemical parameters (pH, C/N ratio) and nutrient contents (N, P, Ca, Mg, Mn, K) were analyzed in different depth levels. Plant communities were analyzed with the Braun-Blanquet method. To characterize physiognomic adaptation of trees, transects have been determined parallel to slope, measuring tree height, diameter and age. Results show a strong spatial correlation between frozen ground, formation of a thick organic layer (Tangelhumus), azonal plant species distribution and pronounced dwarfing of trees. Surrounding areas with unfrozen subsurface show an - for the particular altitude - expected species and soil composition and normal forest growth. Ellenberg pointer values in central parts of the study sites showed a strong plant adaption to cold temperatures. However, plant sociological analysis did not indicate one clear azonal community, but two different permafrost-plant-communities, one adapted to acidic and the other to calcareous substrates. Dwarf grown trees (e.g. spruce, 63cm high, 122 years old) could be found in permafrost-affected areas of all study sites, while the same species developed normally in the surroundings. Main factor for the physiognomic adaptation seems to be the low temperature in the rooting zone and the correlated shorter vegetation period, as air temperatures and nutrient supplies between the permafrost affected area and its surroundings are comparable. Pronounced interdependencies between frozen ground distribution, vegetation cover and soil development could be verified for all sites. The supercooled subsurface causes reduced decomposition of organic material as well as dwarfing of trees. In return, Tangelhumus and dwarfed trees positively affect supercooling. Dry organic material thermally insulates the subsurface during summer and prevents/delays thawing, while the high thermal conductivity of the moist or frozen Tangelhumus enhances heat flow and supercooling in winter. In addition, dwarfed trees prevent the formation of a consistent insulating snow cover optimizing thermal fluxes between atmosphere and subsurface.

Representing spatial and temporal complexity in ecohydrological models: a meta-analysis focusing on groundwater - surface water interactions

NASA Astrophysics Data System (ADS)

McDonald, Karlie; Mika, Sarah; Kolbe, Tamara; Abbott, Ben; Ciocca, Francesco; Marruedo, Amaia; Hannah, David; Schmidt, Christian; Fleckenstein, Jan; Karuse, Stefan

2016-04-01

Sub-surface hydrologic processes are highly dynamic, varying spatially and temporally with strong links to the geomorphology and hydrogeologic properties of an area. This spatial and temporal complexity is a critical regulator of biogeochemical and ecological processes within the interface groundwater - surface water (GW-SW) ecohydrological interface and adjacent ecosystems. Many GW-SW models have attempted to capture this spatial and temporal complexity with varying degrees of success. The incorporation of spatial and temporal complexity within GW-SW model configuration is important to investigate interactions with transient storage and subsurface geology, infiltration and recharge, and mass balance of exchange fluxes at the GW-SW ecohydrological interface. Additionally, characterising spatial and temporal complexity in GW-SW models is essential to derive predictions using realistic environmental conditions. In this paper we conduct a systematic Web of Science meta-analysis of conceptual, hydrodynamic, and reactive and heat transport models of the GW-SW ecohydrological interface since 2004 to explore how these models handled spatial and temporal complexity. The freshwater - groundwater ecohydrological interface was the most commonly represented in publications between 2004 and 2014 with 91% of papers followed by marine 6% and estuarine systems with 3% of papers. Of the GW-SW models published since 2004, the 52% have focused on hydrodynamic processes and <15% covered more than one process (e.g. heat and reactive transport). Within the hydrodynamic subset, 25% of models focused on a vertical depth of <5m. The primary scientific and technological limitations of incorporating spatial and temporal variability into GW-SW models are identified as the inclusion of woody debris, carbon sources, subsurface geological structures and bioclogging into model parameterization. The technological limitations influence the types of models applied, such as hydrostatic coupled models and fully intrinsic saturated and unsaturated models, and the assumptions or simplifications scientists apply to investigate the GW-SW ecohydrological interface. We investigated the type of modelling approaches applied across different scales (site, reach, catchment, nested catchments) and assessed the simplifications in environmental conditions and complexity that are commonly made in model configuration. Understanding the theoretical concepts that underpin these current modelling approaches is critical for scientists to develop measures to derive predictions from realistic environmental conditions at management relevant scales and establish best-practice modelling approaches for improving the scientific understanding and management of the GW-SW interface. Additionally, the assessment of current modelling approaches informs our proposed framework for the progress of GW-SW models in the future. The framework presented aims to increase future scientific, technological and management integration and the identification of research priorities to allow spatial and temporal complexity to be better incorporated into GW-SW models.

Alaska Open-File Report 127 Assessment of Thermal Springs Sites in Southern Southeastern Alaska - Preliminary Results and Evaluation

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

Motyka, Roman J.; Moorman, Mary A.; Reeder, John W.

1980-06-01

Information has been gathered on 13 reported thermal-spring sites, 12 in southern Southeastern Alaska and one in western British Columbia. Five of the reported sites could not be substantiated by DGGS. The eight known thermal spring sites are associated with grainitic terrain and, except for Baker Island Hot Springs, occur within or near intensively fractured Cretaceous-age pluons of the Coast Range Batholith. Thermal-spring surface temperatures range from 21 C (Twin Lakes) to 91.5 C (Bailey Bay). The greatest discharge occurs at Chief Shakes hot springs (450 1pm). Bell Island Hot Springs, which has about a 100-1 pm discharge and amore » 70 C temperature, has had the most development. Two previously unreported thermal-spring sites, Barnes Lake warm springs and Bradfield hot springs, have a low rate of discharge and respective surface temperatures of about 25 and 54 C. The known thermal springs probably originate from circulation of meteoric waters through deep-seated fracture and fault systems. The chemical constituents of the alkali-sulfate to alkali-chloride thermal waters are probably derived from interaction of the deeply circulating meteoric waters with the granitic wall rocks. Chemical geothermometry suggests subsurface temperatures of 55 to 151 C. If waters are being heated solely by conduction from wall rocks, circulation depths must be about 1.5 to 5 km, assuming geothermal gradients of 30 to 50 C/km. Variations in temperature, discharge, and chemistry were noted at several thermal springs for which previous records are available. A major decrease in silica and potassium concentrations at Chief Shakes hot springs is suggested by comparing recent analyses of water chemistry to Waring's (1917) original analysis. The rate of discharge at Bell Island Hot Springs may have increased by a factor of two since Waring's visit to the springs. Subsurface reservoirs associated with thermal springs in southern Southeastern Alaska are of low temperature and are probably limited in extent, compared to geothermal fields now being used elsewhere in the world. Only the Bell Island and Bailey Bay sites now offer any potential for generation of electricity; these sites could also be used for a variety of direct uses such as space heating, wood or lumber processing, and perhaps aquaculture. The other sites have less potential but could be used locally for space heating or agriculture enhancement.« less

Satellite tidal magnetic signals constrain oceanic lithosphere-asthenosphere boundary.

PubMed

Grayver, Alexander V; Schnepf, Neesha R; Kuvshinov, Alexey V; Sabaka, Terence J; Manoj, Chandrasekharan; Olsen, Nils

2016-09-01

The tidal flow of electrically conductive oceans through the geomagnetic field results in the generation of secondary magnetic signals, which provide information on the subsurface structure. Data from the new generation of satellites were shown to contain magnetic signals due to tidal flow; however, there are no reports that these signals have been used to infer subsurface structure. We use satellite-detected tidal magnetic fields to image the global electrical structure of the oceanic lithosphere and upper mantle down to a depth of about 250 km. The model derived from more than 12 years of satellite data reveals a ≈72-km-thick upper resistive layer followed by a sharp increase in electrical conductivity likely associated with the lithosphere-asthenosphere boundary, which separates colder rigid oceanic plates from the ductile and hotter asthenosphere.

Relative permeability of fractured wellbore cement: an experimental investigation using electrical resistivity monitoring for moisture content

NASA Astrophysics Data System (ADS)

Um, W.; Rod, K. A.; Strickland, C. E.

2016-12-01

Permeability is a critical parameter needed to understand flow in subsurface environments; it is particularly important in deep subsurface reservoirs where multiphase fluid flow is common, such as carbon sequestration and geothermal reservoirs. Cement is used in the annulus of wellbores due to its low permeable properties to seal aquifers, reducing leaks to adjacent strata. Extreme subsurface environments of CO2 storage and geothermal production conditions will eventually reduce the cement integrity, propagating fracture networks and increasing the permeability for air and/or water. To date, there have been no reproducible experimental investigations of relative permeability in fractured wellbore cement published. To address this gap, we conducted a series of experiments using fractured Portland cement monoliths with increasing fracture networks. The monolith cylinder sides were jacketed with heavy-duty moisture-seal heat-shrink tubing, then fractured using shear force applied via a hydraulic press. Fractures were generated with different severity for each of three monoliths. Stainless steel endcaps were fixed to the monoliths using the same shrink-wrapped jacket. Fracture characteristics were determined using X-ray microtomography and image analysis. Flow controllers were used to control flow of water and air to supply continuous water or water plus air, both of which were delivered through the influent end cap. Effluent air flow was monitored using a flow meter, and water flow was measured gravimetrically. To monitor the effective saturation of the fractures, a RCON2 concrete bulk electrical resistivity test device was attached across both endcaps and a 0.1M NaNO3 brine was used as the transport fluid to improve resistivity measurements. Water content correlated to resistivity measurements with a r2 > 0.96. Data from the experiments was evaluated using two relative permeability models, the Corey-curve, often used for modeling relative permeability in porous media, and the X-curve, commonly used to depict the relative permeability of fractures. Relative permeability measurements from the cores containing a higher degree of fracturing showed a better fit to X-curve, while data from the minimally fractured cores were better described by fitting to the Corey-curve.

Interpretation of shallow electrical features from electromagnetic and magnetotelluric surveys at Mount Hood, Oregon

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

Goldstein, N.E.; Mozley, E.; Wilt, M.

1982-04-10

A magnetotelluric survey was conducted at accessible locations around Mount Hood, Oregon. Thirty-eight tensor magnetotelluric (MT) and remote telluric stations were set up in clusters around the volcano except for the northwest quadrant, a wilderness area. Because of limited access, station locations were restricted to elevations below 1829 m. On the basis of the MT results, three areas were later investigated in more detail using a large-moment, controlled-source electromagnetic (EM) system. One-dimensional interpretations of EM and MT data on the northeast flank of the mountain near the Cloud Cap eruptive center and on the south flank near Timberline Lodge showmore » a similar subsurface resistivity pattern: a resistive surface layer 400--700 m thick, underlain by a conductive layer with variable thickness and resistivity of <20 ohm m. It is speculated that the surface layer consists of volcanics partially saturated with cold meteoric water. The underlying conductive zone is presumed to be volcanics saturated with water heated within the region of the central conduit and, possibly, at the Cloud Cap side vent. This hypothesis is supported by the existence of warm springs at the base of the mountain, most notably Swim Warm Springs on the south flank, and by several geothermal test wells, one of which penetrates the conductor south of Timberline Lodge. The mT data typically gave a shallower depth to the conductive zone than did the Em data. On the other hand, MT was better for resolving the thickness of the conductive layer and deeper structure. The MT data show evidence for a moderately conductive north-south structure on the south flank below the Timberline Lodge and for a broad zone of late Tertiary intrusives concealed on the southeast flank.« less

Immobilization of Iodate and Iodide using Iron Oxides through Sorption and Co-precipitation at Hanford Site

NASA Astrophysics Data System (ADS)

Wang, G.; Qafoku, N. P.; Truex, M. J.; Strickland, C. E.; Freedman, V. L.

2017-12-01

Isotopes of iodine were generated during plutonium production at the U.S. Department of Energy (DOE) Hanford Site. The long half-life 129I generated during reactor operations has been released into the subsurface, resulting in several large plumes at the Hanford subsurface. We studied the interaction of iodate (IO3-) and iodide (I-) with Fe oxides. A series of batch experiments were conducted to investigate adsorption and co-precipitation of iodine species in the presence of a variety of Fe oxides, such as ferrihydrite, goethite, hematite and magnetite. In the sorption experiments, each Fe oxide was added to an artificial groundwater containing either iodate or iodide, and reacted at room temperature. The sorption batch experiments for each mineral were conducted at varied initial iodate or iodide concentrations under 3 different pH conditions (pH 5, 7, and 9). In the co-precipitation batch experiments, the initial Fe-mineral-forming solutions were prepared in artificial groundwater containing iodate or iodide. Our results indicate that both sorption and co-precipitation are viable mechanisms of the attenuation of the liquid phase iodine. Species Fe oxides could serve as hosts of iodate and iodide that are present at the Hanford subsurface.

An adaptive Gaussian process-based iterative ensemble smoother for data assimilation

NASA Astrophysics Data System (ADS)

Ju, Lei; Zhang, Jiangjiang; Meng, Long; Wu, Laosheng; Zeng, Lingzao

2018-05-01

Accurate characterization of subsurface hydraulic conductivity is vital for modeling of subsurface flow and transport. The iterative ensemble smoother (IES) has been proposed to estimate the heterogeneous parameter field. As a Monte Carlo-based method, IES requires a relatively large ensemble size to guarantee its performance. To improve the computational efficiency, we propose an adaptive Gaussian process (GP)-based iterative ensemble smoother (GPIES) in this study. At each iteration, the GP surrogate is adaptively refined by adding a few new base points chosen from the updated parameter realizations. Then the sensitivity information between model parameters and measurements is calculated from a large number of realizations generated by the GP surrogate with virtually no computational cost. Since the original model evaluations are only required for base points, whose number is much smaller than the ensemble size, the computational cost is significantly reduced. The applicability of GPIES in estimating heterogeneous conductivity is evaluated by the saturated and unsaturated flow problems, respectively. Without sacrificing estimation accuracy, GPIES achieves about an order of magnitude of speed-up compared with the standard IES. Although subsurface flow problems are considered in this study, the proposed method can be equally applied to other hydrological models.

Interplay between microorganisms and geochemistry in geological carbon storage

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

Altman, Susan J.; Kirk, Matthew Fletcher; Santillan, Eugenio-Felipe U.

Researchers at the Center for Frontiers of Subsurface Energy Security (CFSES) have conducted laboratory and modeling studies to better understand the interplay between microorganisms and geochemistry for geological carbon storage (GCS). We provide evidence of microorganisms adapting to high pressure CO 2 conditions and identify factors that may influence survival of cells to CO 2 stress. Factors that influenced the ability of cells to survive exposure to high-pressure CO 2 in our experiments include mineralogy, the permeability of cell walls and/or membranes, intracellular buffering capacity, and whether cells live planktonically or within biofilm. Column experiments show that, following exposure tomore » acidic water, biomass can remain intact in porous media and continue to alter hydraulic conductivity. Our research also shows that geochemical changes triggered by CO 2 injection can alter energy available to populations of subsurface anaerobes and that microbial feedbacks on this effect can influence carbon storage. Our research documents the impact of CO 2 on microorganisms and in turn, how subsurface microorganisms can influence GCS. Furthermore, we conclude that microbial presence and activities can have important implications for carbon storage and that microorganisms should not be overlooked in further GCS research.« less

Interplay between microorganisms and geochemistry in geological carbon storage

DOE PAGES

Altman, Susan J.; Kirk, Matthew Fletcher; Santillan, Eugenio-Felipe U.; ...

2016-02-28

Researchers at the Center for Frontiers of Subsurface Energy Security (CFSES) have conducted laboratory and modeling studies to better understand the interplay between microorganisms and geochemistry for geological carbon storage (GCS). We provide evidence of microorganisms adapting to high pressure CO 2 conditions and identify factors that may influence survival of cells to CO 2 stress. Factors that influenced the ability of cells to survive exposure to high-pressure CO 2 in our experiments include mineralogy, the permeability of cell walls and/or membranes, intracellular buffering capacity, and whether cells live planktonically or within biofilm. Column experiments show that, following exposure tomore » acidic water, biomass can remain intact in porous media and continue to alter hydraulic conductivity. Our research also shows that geochemical changes triggered by CO 2 injection can alter energy available to populations of subsurface anaerobes and that microbial feedbacks on this effect can influence carbon storage. Our research documents the impact of CO 2 on microorganisms and in turn, how subsurface microorganisms can influence GCS. Furthermore, we conclude that microbial presence and activities can have important implications for carbon storage and that microorganisms should not be overlooked in further GCS research.« less

How does subsurface retain and release stored water? An explicit estimation of young water fraction and mean transit time

NASA Astrophysics Data System (ADS)

Ameli, Ali; McDonnell, Jeffrey; Laudon, Hjalmar; Bishop, Kevin

2017-04-01

The stable isotopes of water have served science well as hydrological tracers which have demonstrated that there is often a large component of "old" water in stream runoff. It has been more problematic to define the full transit time distribution of that stream water. Non-linear mixing of previous precipitation signals that is stored for extended periods and slowly travel through the subsurface before reaching the stream results in a large range of possible transit times. It difficult to find tracers can represent this, especially if all that one has is data on the precipitation input and the stream runoff. In this paper, we explicitly characterize this "old water" displacement using a novel quasi-steady physically-based flow and transport model in the well-studied S-Transect hillslope in Sweden where the concentration of hydrological tracers in the subsurface and stream has been measured. We explore how subsurface conductivity profile impacts the characteristics of old water displacement, and then test these scenarios against the observed dynamics of conservative hydrological tracers in both the stream and subsurface. This work explores the efficiency of convolution-based approaches in the estimation of stream "young water" fraction and time-variant mean transit times. We also suggest how celerity and velocity differ with landscape structure

Phase diagram and density of fluids in the water-methanol system: experiments and implications for the crystallization and dynamics of subsurface oceans in icy moons

NASA Astrophysics Data System (ADS)

Yao, C.; Mantegazzi, D.; Deschamps, F.; Sanchez-Valle, C.

2013-12-01

Methanol, CH3OH, has been recently observed in several comets and at the surface of Saturn's icy moon Enceladus, [Hodyss et al., 2009]. Its plausible presence in the subsurface ocean could significantly affect the thermal and structural evolution of the satellite [Deschamps et al., 2010]. Methanol lowers the melting temperature of water ice [Vuillard & Sanchez, 1961; Miller & Carpenter, 1964], hence decreasing the efficiency of convective heat transfer through the outer ice Ih shell, and affects the subsurface ocean density and thermo-chemical evolution. However, the phase diagram and the fluid density of the H2O - CH3OH system remains largely unknown at the high pressures and low temperature conditions relevant for the icy moon interiors. In this study, we determined experimentally the liquidus temperature of Ice Ih and Ice VI and the fluid density in the binary water-methanol system (5, 10 and 20 w% CH3OH) from sound velocity measurments by Brillouin scattering spectroscopy over the P-T range 230 - 300 K and 10-4 - 1.2 GPa. The experiments were conducted using a membrane-type diamond anvil cell (mDAC) and an in-house designed Peltier cooling system to achieve the low temperatures of interest. Melting and crystallization in the system was visually monitored and confirmed from changes in the Brillouin spectra and in the pressure dependence of the measured sound velocities. The density of fluids ρ(P, T,x) in the binary system weas determined from the inversion of sound velocities measured in the fluids as a function of pressure along isotherms from 230 to 300 K. The results are used to propose a thermodynamic model for the CH3OH-H2O system over the investigated P-T range and further used to examine the effect of the methanol on the crystallization and thermo-chemical evolution of the subsurface ocean. The implications of these results for the thermal and structural evolution of icy moons, with particular applications to Titan, will be further discussed. References : Deschamps, F., Mousis, O., Sanchez-Valle, C., and Lunine, J.I., Astrophys. J., 2010. Hodyss, R., Parkinson, C.D. Johnson, V.D., Stern, J.V., Goguen, J.D, Yung, Y.L., and Kanik, I., Geophys. Res. Lett., 1992. Miller, G.A., and Carpenter, D.A., J. Chem. Eng. Data, 1964. Vuillard, G., and Sanchez, M., Bull. Soc. Chim. France, 1961.

Fiber Optic Thermal Health Monitoring of Aerospace Structures and Materials

NASA Technical Reports Server (NTRS)

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

2009-01-01

A new technique is presented for thermographic detection of flaws in materials and structures by performing temperature measurements with fiber Bragg gratings. Individual optical fibers with multiple Bragg gratings employed as surface temperature sensors were bonded to the surfaces of structures with subsurface defects or thickness variations. Both during and following the application of a thermal heat flux to the surface, the individual Bragg grating sensors measured the temporal and spatial temperature variations. The investigated structures included a 10-ply composite specimen with subsurface delaminations of various sizes and depths. The data obtained from grating sensors were further analyzed with thermal modeling to reveal particular characteristics of the interested areas. These results were found to be consistent with those from conventional thermography techniques. Limitations of the technique were investigated using both experimental and numerical simulation techniques. Methods for performing in-situ structural health monitoring are discussed.

National assessment of geologic carbon dioxide storage resources: methodology implementation

USGS Publications Warehouse

Blondes, Madalyn S.; Brennan, Sean T.; Merrill, Matthew D.; Buursink, Marc L.; Warwick, Peter D.; Cahan, Steven M.; Corum, Margo D.; Cook, Troy A.; Craddock, William H.; DeVera, Christina A.; Drake II, Ronald M.; Drew, Lawrence J.; Freeman, P.A.; Lohr, Celeste D.; Olea, Ricardo A.; Roberts-Ashby, Tina L.; Slucher, Ernie R.; Varela, Brian A.

2013-01-01

In response to the 2007 Energy Independence and Security Act, the U.S. Geological Survey (USGS) conducted a national assessment of potential geologic storage resources for carbon dioxide (CO2). Storage of CO2 in subsurface saline formations is one important method to reduce greenhouse gas emissions and curb global climate change. This report provides updates and implementation details of the assessment methodology of Brennan and others (2010, http://pubs.usgs.gov/of/2010/1127/) and describes the probabilistic model used to calculate potential storage resources in subsurface saline formations.

Functional environmental proteomics: elucidating the role of a c-type cytochrome abundant during uranium bioremediation

PubMed Central

Yun, Jiae; Malvankar, Nikhil S; Ueki, Toshiyuki; Lovley, Derek R

2016-01-01

Studies with pure cultures of dissimilatory metal-reducing microorganisms have demonstrated that outer-surface c-type cytochromes are important electron transfer agents for the reduction of metals, but previous environmental proteomic studies have typically not recovered cytochrome sequences from subsurface environments in which metal reduction is important. Gel-separation, heme-staining and mass spectrometry of proteins in groundwater from in situ uranium bioremediation experiments identified a putative c-type cytochrome, designated Geobacter subsurface c-type cytochrome A (GscA), encoded within the genome of strain M18, a Geobacter isolate previously recovered from the site. Homologs of GscA were identified in the genomes of other Geobacter isolates in the phylogenetic cluster known as subsurface clade 1, which predominates in a diversity of Fe(III)-reducing subsurface environments. Most of the gscA sequences recovered from groundwater genomic DNA clustered in a tight phylogenetic group closely related to strain M18. GscA was most abundant in groundwater samples in which Geobacter sp. predominated. Expression of gscA in a strain of Geobacter sulfurreducens that lacked the gene for the c-type cytochrome OmcS, thought to facilitate electron transfer from conductive pili to Fe(III) oxide, restored the capacity for Fe(III) oxide reduction. Atomic force microscopy provided evidence that GscA was associated with the pili. These results demonstrate that a c-type cytochrome with an apparent function similar to that of OmcS is abundant when Geobacter sp. are abundant in the subsurface, providing insight into the mechanisms for the growth of subsurface Geobacter sp. on Fe(III) oxide and suggesting an approach for functional analysis of other Geobacter proteins found in the subsurface. PMID:26140532

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

NASA Astrophysics Data System (ADS)

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

2014-05-01

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

3D Seismic Imaging over a Potential Collapse Structure

NASA Astrophysics Data System (ADS)

Gritto, Roland; O'Connell, Daniel; Elobaid Elnaiem, Ali; Mohamed, Fathelrahman; Sadooni, Fadhil

2016-04-01

The Middle-East has seen a recent boom in construction including the planning and development of complete new sub-sections of metropolitan areas. Before planning and construction can commence, however, the development areas need to be investigated to determine their suitability for the planned project. Subsurface parameters such as the type of material (soil/rock), thickness of top soil or rock layers, depth and elastic parameters of basement, for example, comprise important information needed before a decision concerning the suitability of the site for construction can be made. A similar problem arises in environmental impact studies, when subsurface parameters are needed to assess the geological heterogeneity of the subsurface. Environmental impact studies are typically required for each construction project, particularly for the scale of the aforementioned building boom in the Middle East. The current study was conducted in Qatar at the location of a future highway interchange to evaluate a suite of 3D seismic techniques in their effectiveness to interrogate the subsurface for the presence of karst-like collapse structures. The survey comprised an area of approximately 10,000 m2 and consisted of 550 source- and 192 receiver locations. The seismic source was an accelerated weight drop while the geophones consisted of 3-component 10 Hz velocity sensors. At present, we analyzed over 100,000 P-wave phase arrivals and performed high-resolution 3-D tomographic imaging of the shallow subsurface. Furthermore, dispersion analysis of recorded surface waves will be performed to obtain S-wave velocity profiles of the subsurface. Both results, in conjunction with density estimates, will be utilized to determine the elastic moduli of the subsurface rock layers.

Functional environmental proteomics: elucidating the role of a c-type cytochrome abundant during uranium bioremediation.

PubMed

Yun, Jiae; Malvankar, Nikhil S; Ueki, Toshiyuki; Lovley, Derek R

2016-02-01

Studies with pure cultures of dissimilatory metal-reducing microorganisms have demonstrated that outer-surface c-type cytochromes are important electron transfer agents for the reduction of metals, but previous environmental proteomic studies have typically not recovered cytochrome sequences from subsurface environments in which metal reduction is important. Gel-separation, heme-staining and mass spectrometry of proteins in groundwater from in situ uranium bioremediation experiments identified a putative c-type cytochrome, designated Geobacter subsurface c-type cytochrome A (GscA), encoded within the genome of strain M18, a Geobacter isolate previously recovered from the site. Homologs of GscA were identified in the genomes of other Geobacter isolates in the phylogenetic cluster known as subsurface clade 1, which predominates in a diversity of Fe(III)-reducing subsurface environments. Most of the gscA sequences recovered from groundwater genomic DNA clustered in a tight phylogenetic group closely related to strain M18. GscA was most abundant in groundwater samples in which Geobacter sp. predominated. Expression of gscA in a strain of Geobacter sulfurreducens that lacked the gene for the c-type cytochrome OmcS, thought to facilitate electron transfer from conductive pili to Fe(III) oxide, restored the capacity for Fe(III) oxide reduction. Atomic force microscopy provided evidence that GscA was associated with the pili. These results demonstrate that a c-type cytochrome with an apparent function similar to that of OmcS is abundant when Geobacter sp. are abundant in the subsurface, providing insight into the mechanisms for the growth of subsurface Geobacter sp. on Fe(III) oxide and suggesting an approach for functional analysis of other Geobacter proteins found in the subsurface.

Design, construction, operation, and evaluation of solar systems for industrial process-heat applications in the intermediate-temperature range (212/sup 0/F to 550/sup 0/F). Environmental assessment

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

None

1982-01-01

The environmental impacts are assessed for a proposed 50,000 square foot field of single axis tracking, concentrating solar collectors along the Ohio River in southern Ohio. The facility is planned to produce process steam for use in the production of polystyrene. Absorbed solar energy would heat an aliphatic hydrocarbon synthetic heat transfer fluid to a maximum temperature of 500/sup 0/F. The existing environment is briefly described, particularly regarding air quality. The potential environmental impacts of the solar process heat system on the air, water, soil, endangered species and archaeological and historical resources are examined, including risks due to flood andmore » glare and a comparison of alternatives. Also included are a Consent Judgment relating to two coal-fired boilers in violation of EPA regulations, property data of Gulf Synfluid 4CS (a candidate heat transfer fluid), piping and instrumentation diagrams and schematics, site grade and drainage plan, geological survey map, subsurface soil investigation, Ohio endangered species list, Ohio Archaeological Counsel certification list, and a study of heat transfer fluids and their properties. (LEW)« less

Thermal energy storage with geothermal triplet for space heating and cooling

NASA Astrophysics Data System (ADS)

Bloemendal, Martin; Hartog, Niels

2017-04-01

Many governmental organizations and private companies have set high targets in avoiding CO2 emissions and reducing energy (Kamp, 2015; Ministry-of-Economic-affairs, 2016). ATES systems use groundwater wells to overcome the discrepancy in time between the availability of heat (during summer) and the demand for heat (during winter). Aquifer Thermal Energy Storage is an increasingly popular technique; currently over 2000 ATES systems are operational in the Netherlands (Graaf et al., 2016). High temperature ATES may help to improve performance of these conventional ATES systems. ATES systems use heat pumps to get the stored heat to the required temperature for heating of around 40-50°C and to produce the cold water for cooling in summer. These heat pumps need quite a lot of power to run; on average an ATES system produces 3-4 times less CO2 emission compared to conventional. Over 60% of those emission are accounted for by the heat pump (Dekker, 2016). This heat pump power consumption can be reduced by utilizing other sources of sustainable heat and cooling capacity for storage in the subsurface. At such operating temperatures the required storage temperatures do no longer match the return temperatures in the building systems. Therefore additional components and an additional well are required to increase the groundwater temperature in summer (e.g. solar collectors) and decrease it in winter (e.g. dry coolers). To prevent "pollution" of the warm and cold well return water from the building can be stored in a third well until weather conditions are suitable for producing the required storage temperature. Simulations and an economical evaluation show great potential for this type of aquifer thermal energy storage; economic performance is better than normal ATES while the emissions are reduce by a factor ten. At larger temperature differences, also the volume of groundwater required to pump around is much less, which causes an additional energy saving. Research now focusses on energy balance and energy loss in the subsurface, well design requirements, working/operational conditions of each well, as well as building system components like the influence of weather conditions on performance of system components. At EGU we like to present and discuss the results of this research. references • Dekker, L.d., 2016. Bepalende factoren voor goed functionerende WKO, kennisplatform bodemenergie. • Graaf, A.d., Heijer, R., Postma, S., 2016. Evaluatie Wijzigingsbesluit bodemenergiesystemen. Buro 38 in commision of ministry of Intrastructure and environment, Cothen. • Kamp, H., 2015. Warmtevisie, ministry of economic affairs, Den Haag. • Ministry-of-Economic-affairs, 2016. Energieagenda, Naar een CO₂-arme energievoorziening. Ministry of Economic affairs, Den Haag.

Design Evolution Study - Aging Options

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

P. McDaniel

The purpose of this study is to identify options and issues for aging commercial spent nuclear fuel received for disposal at the Yucca Mountain Mined Geologic Repository. Some early shipments of commercial spent nuclear fuel to the repository may be received with high-heat-output (younger) fuel assemblies that will need to be managed to meet thermal goals for emplacement. The capability to age as much as 40,000 metric tons of heavy metal of commercial spent nuclear he1 would provide more flexibility in the design to manage this younger fuel and to decouple waste receipt and waste emplacement. The following potential agingmore » location options are evaluated: (1) Surface aging at four locations near the North Portal; (2) Subsurface aging in the permanent emplacement drifts; and (3) Subsurface aging in a new subsurface area. The following aging container options are evaluated: (1) Complete Waste Package; (2) Stainless Steel inner liner of the waste package; (3) Dual Purpose Canisters; (4) Multi-Purpose Canisters; and (5) New disposable canister for uncanistered commercial spent nuclear fuel. Each option is compared to a ''Base Case,'' which is the expected normal waste packaging process without aging. A Value Engineering approach is used to score each option against nine technical criteria and rank the options. Open issues with each of the options and suggested future actions are also presented. Costs for aging containers and aging locations are evaluated separately. Capital costs are developed for direct costs and distributable field costs. To the extent practical, unit costs are presented. Indirect costs, operating costs, and total system life cycle costs will be evaluated outside of this study. Three recommendations for aging commercial spent nuclear fuel--subsurface, surface, and combined surface and subsurface are presented for further review in the overall design re-evaluation effort. Options that were evaluated but not recommended are: subsurface aging in a new subsurface area (high cost); surface aging in the complete waste package (risk to the waste package and impact on the Waste Handling Facility); and aging in the stainless steel liner (impact on the waste package design and new high risk operations added to the waste packaging process). The selection of a design basis for aging will be made in conjunction with the other design re-evaluation studies.« less

Electrical resistance tomography using steel cased boreholes as electrodes

DOEpatents

Daily, W.D.; Ramirez, A.L.

1999-06-22

An electrical resistance tomography method is described which uses steel cased boreholes as electrodes. The method enables mapping the electrical resistivity distribution in the subsurface from measurements of electrical potential caused by electrical currents injected into an array of electrodes in the subsurface. By use of current injection and potential measurement electrodes to generate data about the subsurface resistivity distribution, which data is then used in an inverse calculation, a model of the electrical resistivity distribution can be obtained. The inverse model may be constrained by independent data to better define an inverse solution. The method utilizes pairs of electrically conductive (steel) borehole casings as current injection electrodes and as potential measurement electrodes. The greater the number of steel cased boreholes in an array, the greater the amount of data is obtained. The steel cased boreholes may be utilized for either current injection or potential measurement electrodes. The subsurface model produced by this method can be 2 or 3 dimensional in resistivity depending on the detail desired in the calculated resistivity distribution and the amount of data to constrain the models. 2 figs.

Electrical resistance tomography using steel cased boreholes as electrodes

DOEpatents

Daily, William D.; Ramirez, Abelardo L.

1999-01-01

An electrical resistance tomography method using steel cased boreholes as electrodes. The method enables mapping the electrical resistivity distribution in the subsurface from measurements of electrical potential caused by electrical currents injected into an array of electrodes in the subsurface. By use of current injection and potential measurement electrodes to generate data about the subsurface resistivity distribution, which data is then used in an inverse calculation, a model of the electrical resistivity distribution can be obtained. The inverse model may be constrained by independent data to better define an inverse solution. The method utilizes pairs of electrically conductive (steel) borehole casings as current injection electrodes and as potential measurement electrodes. The greater the number of steel cased boreholes in an array, the greater the amount of data is obtained. The steel cased boreholes may be utilized for either current injection or potential measurement electrodes. The subsurface model produced by this method can be 2 or 3 dimensional in resistivity depending on the detail desired in the calculated resistivity distribution and the amount of data to constain the models.

New Insights on Subsurface Imaging of Carbon Nanotubes in Polymer Composites via Scanning Electron Microscopy

NASA Technical Reports Server (NTRS)

Zhao, Minhua; Ming, Bin; Kim, Jae-Woo; Gibbons, Luke J.; Gu, Xiaohong; Nguyen, Tinh; Park, Cheol; Lillehei, Peter T.; Villarrubia, J. S.; Vladar, Andras E.;

Subsurface drip application of alternative fumigants to methyl bromide for controlling nematodes in replanted grapevines.

PubMed

Cabrera, J Alfonso; Wang, Dong; Schneider, Sally M; Hanson, Bradley D

2012-05-01

Many California grape growers use preplant fumigation to ensure uniform and healthy grapevine establishment in replant situations. A field study was conducted to evaluate the performance of subsurface drip-applied chemical alternatives to methyl bromide on plant-parasitic nematodes, plant vigor and fruit yield during the 6 year period following replanting. Subsurface drip fumigation with 1,3-dichloropropene plus chloropicrin and with iodomethane plus chloropicrin had generally similar nematicide activity as methyl bromide in three grape types, while sodium azide was less effective. The combination of 1,3-dichloropropene plus chloropicrin enhanced vine vigor similarly to methyl bromide. However, all plots treated with alternative fumigants produced less fruit yield than methyl bromide over the 4 years of evaluation. Subsurface drip fumigation with alternative chemicals to methyl bromide generally provided adequate management of plant-parasitic nematodes during the vine establishment period. However, further research is required to increase the performance of alternative chemicals against other components of the replant problem, as grape yield in vines grown in the alternative treatments was lower than in methyl bromide. Copyright © 2011 Society of Chemical Industry.

Subsurface Investigation using 2D Resistivity and Ground Penetrating Radar at Teluk Kumbar, Penang

NASA Astrophysics Data System (ADS)

Teoh, YJ; Bruka, MA; Idris, NM; Ismail, NA; Muztaza, NM

2018-04-01

The objective of this study is to determine the structure and condition of the subsurface by using 2D resistivity and Ground Penetrating Radar (GPR) methods. The study was conducted at SK Sungai Batu, Teluk Kumbar, Penang Island. For 2D resistivity method, Wenner-Schlumberger array was used while for GPR, 250 MHz antenna was used at the site. The survey consists of 200m length survey line. GPR result shows that there is high intensity of EM. 2D resistivity result shows that the low resistivity region (200 Ωm to 340 Ωm) appears to be at the centre of the survey line from depth 7 m to 13 m. Meanwhile, the higher resistivity region (4000 Ωm to 6000 Ωm) may indicate the bedrock structure of the subsurface, which is the granitic rock. This region is bedrock which rested at depth 14 m and below. In conclusion, data obtained from GPR and 2D resistivity methods can be easily correlated to determine the features of the subsurface.

Crystal Orientation Effect on the Subsurface Deformation of Monocrystalline Germanium in Nanometric Cutting.

PubMed

Lai, Min; Zhang, Xiaodong; Fang, Fengzhou

2017-12-01

Molecular dynamics simulations of nanometric cutting on monocrystalline germanium are conducted to investigate the subsurface deformation during and after nanometric cutting. The continuous random network model of amorphous germanium is established by molecular dynamics simulation, and its characteristic parameters are extracted to compare with those of the machined deformed layer. The coordination number distribution and radial distribution function (RDF) show that the machined surface presents the similar amorphous state. The anisotropic subsurface deformation is studied by nanometric cutting on the (010), (101), and (111) crystal planes of germanium, respectively. The deformed structures are prone to extend along the 110 slip system, which leads to the difference in the shape and thickness of the deformed layer on various directions and crystal planes. On machined surface, the greater thickness of subsurface deformed layer induces the greater surface recovery height. In order to get the critical thickness limit of deformed layer on machined surface of germanium, the optimized cutting direction on each crystal plane is suggested according to the relevance of the nanometric cutting to the nanoindentation.

Year-to-year instability of the Mars south polar cap

NASA Technical Reports Server (NTRS)

Jakosky, Bruce M.; Haberle, Robert M.

1990-01-01

Models of the Mars polar cap energy balance suggest that the south cap has two possible configurations at the current epoch. It can be covered all year by CO2 frost, as was observed by the Viking spacecraft, or the CO2 frost can disappear at midsummer to expose an underlying surface. The difference between the two states depends on the role of energy conducted into the subsurface. If the cap was exposed the previous year, conducted energy will cause less CO2 frost to condense in winter, and the frost will disappear completely in summer. If the cap was covered the previous year, there will be no conducted energy, and it will stay covered again. Subtle effects in the atmosphere can perturb the cap energy balance sufficiently to cause the cap to jump between states. This behavior might provide an explanation for the large southern summer water vapor abundances observed in 1969. It also explains the observed differences between the north and the south residual caps as resulting in part from a difference in the role in the annual energy balance of energy conducted into the subsurface.

Field observations of extended seawater intrusion through subsurface karst conduit networks at Wakulla Spring in the Woodville Karst Plain, Florida

NASA Astrophysics Data System (ADS)

Xu, Z.; Bassett, S.; Hu, B. X.; Dyer, S.

2016-12-01

Five periods of increased electrical conductivity have been found in the karst conduits supplying one of the largest first magnitude springs in Florida with water. Numerous well-developed conduit networks are distributed in the Woodville Karst Plain (WKP), Florida and connected to the Gulf of Mexico. A composite analysis of precipitation and electric conductivity data provides strong evidence that the increases in conductivity are directly tied to seawater intrusion moving inland and traveling 14 miles against the prevailing regional hydraulic gradient from from Spring Creek Spring Complex (SCSC), a group of submarine springs at the Gulf Coast. A geochemical analysis of samples from the spring vent rules out anthropogenic contamination and upwelling regional recharge from the deep aquifer as sources of the rising conductivity. The interpretation is supported by the conceptual model established by prior researchers working to characterize the study area. This abstract documented the first and longest case of seawater intrusion in the WKP, and also indicates significant possibility of seawater contamination through subsurface conduit networks in a coastal karst aquifer.

In vitro burn model illustrating heat conduction patterns using compressed thermal papers.

PubMed

Lee, Jun Yong; Jung, Sung-No; Kwon, Ho

2015-01-01

To date, heat conduction from heat sources to tissue has been estimated by complex mathematical modeling. In the present study, we developed an intuitive in vitro skin burn model that illustrates heat conduction patterns inside the skin. This was composed of tightly compressed thermal papers with compression frames. Heat flow through the model left a trace by changing the color of thermal papers. These were digitized and three-dimensionally reconstituted to reproduce the heat conduction patterns in the skin. For standardization, we validated K91HG-CE thermal paper using a printout test and bivariate correlation analysis. We measured the papers' physical properties and calculated the estimated depth of heat conduction using Fourier's equation. Through contact burns of 5, 10, 15, 20, and 30 seconds on porcine skin and our burn model using a heated brass comb, and comparing the burn wound and heat conduction trace, we validated our model. The heat conduction pattern correlation analysis (intraclass correlation coefficient: 0.846, p < 0.001) and the heat conduction depth correlation analysis (intraclass correlation coefficient: 0.93, p < 0.001) showed statistically significant high correlations between the porcine burn wound and our model. Our model showed good correlation with porcine skin burn injury and replicated its heat conduction patterns. © 2014 by the Wound Healing Society.

Experimental and numerical study on thermal conductivity of partially saturated unconsolidated sands

NASA Astrophysics Data System (ADS)

Lee, Youngmin; Keehm, Youngseuk; Kim, Seong-Kyun; Shin, Sang Ho

2016-04-01

A class of problems in heat flow applications requires an understanding of how water saturation affects thermal conductivity in the shallow subsurface. We conducted a series of experiments using a sand box to evaluate thermal conductivity (TC) of partially saturated unconsolidated sands under varying water saturation (Sw). We first saturated sands fully with water and varied water saturation by drainage through the bottom of the sand box. Five water-content sensors were integrated vertically into the sand box to monitor water saturation changes and a needle probe was embedded to measure thermal conductivity of partially saturated sands. The experimental result showed that thermal conductivity decreases from 2.5 W/mK for fully saturated sands to 0.7 W/mK when water saturation is 5%. We found that the decreasing trend is quite non-linear: highly sensitive at very high and low water saturations. However, the boundary effects on the top and the bottom of the sand box seemed to be responsible for this high nonlinearity. We also found that the determination of water saturation is quite important: the saturation by averaging values from all five sensors and that from the sensor at the center position, showed quite different trends in the TC-Sw domain. In parallel, we conducted a pore-scale numerical modeling, which consists of the steady-state two-phase Lattice-Boltzmann simulator and FEM thermal conduction simulator on digital pore geometry of sand aggregation. The simulation results showed a monotonous decreasing trend, and are reasonably well matched with experimental data when using average water saturations. We concluded that thermal conductivity would decrease smoothly as water saturation decreases if we can exclude boundary effects. However, in dynamic conditions, i.e. imbibition or drainage, the thermal conductivity might show hysteresis, which can be investigated with pore-scale numerical modeling with unsteady-state two-phase flow simulators in our future work.

Closing the Seasonal Ocean Surface Temperature Balance in the Eastern Tropical Oceans from Remote Sensing and Model Reanalyses

NASA Technical Reports Server (NTRS)

Roberts, J. Brent; Clayson, C. A.

2012-01-01

Residual forcing necessary to close the MLTB on seasonal time scales are largest in regions of strongest surface heat flux forcing. Identifying the dominant source of error - surface heat flux error, mixed layer depth estimation, ocean dynamical forcing - remains a challenge in the eastern tropical oceans where ocean processes are very active. Improved sub-surface observations are necessary to better constrain errors. 1. Mixed layer depth evolution is critical to the seasonal evolution of mixed layer temperatures. It determines the inertia of the mixed layer, and scales the sensitivity of the MLTB to errors in surface heat flux and ocean dynamical forcing. This role produces timing impacts for errors in SST prediction. 2. Errors in the MLTB are larger than the historical 10Wm-2 target accuracy. In some regions, a larger accuracy can be tolerated if the goal is to resolve the seasonal SST cycle.

Penguin heat-retention structures evolved in a greenhouse Earth.

PubMed

Thomas, Daniel B; Ksepka, Daniel T; Fordyce, R Ewan

2011-06-23

Penguins (Sphenisciformes) inhabit some of the most extreme environments on Earth. The 60+ Myr fossil record of penguins spans an interval that witnessed dramatic shifts in Cenozoic ocean temperatures and currents, indicating a long interplay between penguin evolution and environmental change. Perhaps the most celebrated example is the successful Late Cenozoic invasion of glacial environments by crown clade penguins. A major adaptation that allows penguins to forage in cold water is the humeral arterial plexus, a vascular counter-current heat exchanger (CCHE) that limits heat loss through the flipper. Fossil evidence reveals that the humeral plexus arose at least 49 Ma during a 'Greenhouse Earth' interval. The evolution of the CCHE is therefore unrelated to global cooling or development of polar ice sheets, but probably represents an adaptation to foraging in subsurface waters at temperate latitudes. As global climate cooled, the CCHE was key to invasion of thermally more demanding environments associated with Antarctic ice sheets.

What do they know about Heat and Heat Conduction? A case study to excavate Pre-service Physics Teachers’ Mental Model in Heat and Heat Conduction

NASA Astrophysics Data System (ADS)

Sari, I. M.

2017-02-01

Teacher plays a crucial role in Education. Helping students construct scientifically mental model is one of obligation of Physics Education Department of Teacher Education Institute that produce physics teacher. Excavating students’ mental model is necessary to be done in physics education. This research was first to identify 23 physics students’ mental model of heat and heat conduction. A series of semi-structured interviews was conducted to excavate the students’ understanding of heat and mental models on heat conduction. The students who involved in this study come from different level from sophomore to master degree in Physics Education Department. This study adopted a constant comparison method to obtain the patterns of the participants’ responses through the students’ writing, drawing and verbal utterances. The framework for assessing mental model and the instruments were adopted and adapted from Chiou and Anderson (2010). We also compared the students’ understanding of heat and mental models on heat conduction. The result shows that Heat is treated as Intrinsic property, material substances, and caloric flow. None of students expressed heat as transfer of thermal energy. Moreover, there are two kinds of students’ fundamental component of mental model in heat conduction were found: medium and molecules. Students understanding of heat and fundamental components of mental model in heat conduction are not resulted from running mental model.

Finite Element Modeling of the Thermographic Inspection for Composite Materials

NASA Technical Reports Server (NTRS)

Bucinell, Ronald B.

1996-01-01

The performance of composite materials is dependent on the constituent materials selected, material structural geometry, and the fabrication process. Flaws can form in composite materials as a result of the fabrication process, handling in the manufacturing environment, and exposure in the service environment to anomalous activity. Often these flaws show no indication on the surface of the material while having the potential of substantially degrading the integrity of the composite structure. For this reason it is important to have available inspection techniques that can reliably detect sub-surface defects such as inter-ply disbonds, inter-ply cracks, porosity, and density changes caused by variations in fiber volume content. Many non-destructive evaluation techniques (NDE) are capable of detecting sub-surface flaws in composite materials. These include shearography, video image correlation, ultrasonic, acoustic emissions, and X-ray. The difficulty with most of these techniques is that they are time consuming and often difficult to apply to full scale structures. An NDE technique that appears to have the capability to quickly and easily detect flaws in composite structure is thermography. This technique uses heat to detect flaws. Heat is applied to the surface of a structure with the use of a heat lamp or heat gun. A thermographic camera is then pointed at the surface and records the surface temperature as the composite structure cools. Flaws in the material will cause the thermal-mechanical material response to change. Thus, the surface over an area where a flaw is present will cool differently than regions where flaws do not exist. This paper discusses the effort made to thermo-mechanically model the thermography process. First the material properties and physical parameters used in the model will be explained. This will be followed by a detailed discussion of the finite element model used. Finally, the result of the model will be summarized along with recommendations for future work.

Cooling device featuring thermoelectric and diamond materials for temperature control of heat-dissipating devices

NASA Technical Reports Server (NTRS)

Vandersande, Ian W. (Inventor); Ewell, Richard (Inventor); Fleurial, Jean-Pierre (Inventor); Lyon, Hylan B. (Inventor)

1998-01-01

A cooling device for lowering the temperature of a heat-dissipating device. The cooling device includes a heat-conducting substrate (composed, e.g., of diamond or another high thermal conductivity material) disposed in thermal contact with the heat-dissipating device. During operation, heat flows from the heat-dissipating device into the heat-conducting substrate, where it is spread out over a relatively large area. A thermoelectric cooling material (e.g., a Bi.sub.2 Te.sub.3 -based film or other thermoelectric material) is placed in thermal contact with the heat-conducting substrate. Application of electrical power to the thermoelectric material drives the thermoelectric material to pump heat into a second heat-conducting substrate which, in turn, is attached to a heat sink.

Forcing and Responses of the Surface Energy Budget at Summit, Greenland

NASA Astrophysics Data System (ADS)

Miller, Nathaniel B.

Energy exchange at the Greenland Ice Sheet surface governs surface temperature variability, a factor critical for representing increasing surface melt extent, which portends a rise in global sea level. A comprehensive set of cloud, tropospheric, near-surface and sub-surface measurements at Summit Station is utilized to determine the driving forces and subsequent responses of the surface energy budget (SEB). This budget includes radiative, turbulent, and ground heat fluxes, and ultimately controls the evolution of surface temperature. At Summit Station, clouds radiatively warm the surface in all months with an annual average cloud radiative forcing value of 33 W m -2, largely driven by the occurrence of liquid-bearing clouds. The magnitude of the surface temperature response is dependent on how turbulent and ground heat fluxes modulate changes to radiative forcing. Relationships between forcing terms and responding surface fluxes show that changes in the upwelling longwave radiation compensate for 65-85% (50- 60%) of the total change in radiative forcing in the winter (summer). The ground heat flux is the second largest response term (16% annually), especially during winter. Throughout the annual cycle, the sensible heat flux response is comparatively constant (9%) and latent heat flux response is only 1.5%, becoming more of a factor in modulating surface temperature responses during the summer. Combining annual cycles of these responses with cloud radiative forcing results, clouds warm the surface by an estimated 7.8°C annually. A reanalysis product (ERA-I), operational model (CFSv2), and climate model (CESM) are evaluated utilizing the comprehensive set of SEB observations and process-based relationships. Annually, surface temperatures in each model are warmer than observed with overall poor representation of the coldest surface temperatures. Process-based relationships between different SEB flux terms offer insight into how well a modeling framework represents physical processes and the ability to distinguish errors in forcing versus those in physical representation. Such relationships convey that all three models underestimate the response of surface temperatures to changes in radiative forcing. These results provide a method to expose model deficiencies and indicate the importance of representing surface, sub-surface and boundary-layer processes when portraying cloud impacts on surface temperature variability.

On the characterization of subsurface flow and hydraulic conductivity from surface SP measurements: correcting for electrical heterogeneities.

NASA Astrophysics Data System (ADS)

Sailhac, P.; Marquis, G.; Darnet, M.; Szalai, S.

2003-04-01

Surface self potential measurements (SP) are useful to characterize underground fluid flow or chemical reactions (as redox) and can be used in addition to NMR and electrical prospecting in hydrological investigations. Assuming that the SP anomalies have an electrokinetic origin, the source of SP data is the divergence of underground fluid flow; one important problem with surface SP data is then its interpretation in terms of fluid flow geometry. Some integral transform techniques have been shown to be powerful for SP interpretation (e.g. Fournier 1989, Patella, 1997; Sailhac &Marquis 2001). All these techniques are based upon Green’{ }s functions to characterize underground water flow, but they assume a constant electrical conductivity in the subsurface. This unrealistic approximation results in the appearance of non-electrokinetic sources at strong lateral electrical conductivity contrasts. We present here new Green’{ }s functions suitable for media of heterogeneous electrical conductivity. This new approach allows the joint interpretation of electrical resistivity tomography and SP measurements to detect electrokinetic sources caused by fluid flow. Tests on synthetic examples show that it gives more realistic results that when a constant electrical conductivity is assumed.

Synchronous infrared imaging methods to characterize thermal properties of materials

NASA Astrophysics Data System (ADS)

Ouyang, Zhong

1999-11-01

A fundamental thermal property of a material is its thermal conductivity. The current state-of-the art for measurement of thermal conductivity is inadequate, especially in the case of composite materials. This dissertation addresses the need for a rapid and accurate measurement of thermal conductivity that can provide values for three orthogonal directions in a single measurement. The theoretical approach is based on three-dimensional thermal wave propagation and scattering treatments that have been developed earlier at Wayne State University. The experimental approach makes use of a state-of-the-art focal-plane-array infrared camera, which is used to follow the time- and spatial-progression of the planar heat pulse on both surfaces of the slab. The method has been used to determine the thermal diffusivity of six pure elemental single crystal materials (Cu, Ti, Bi, Al, Ag, Pb). The results are in good agreement (better than 1%) with the diffusivities calculated from the handbook. The diffusivities of some alloys and unidirectional graphite-fiber-reinforced-polymer composite also are determined by this method. As a byproduct of one of the experimental approaches measuring the IR radiation from the heated surface, direct evidence is obtained for the presence of a thermal wave "echo". The theory and confirming measurements in this dissertation represent its first clear confirmation. A second experimental method which is studied in this dissertation, and which may be used to characterize thermal properties of materials, is that of lock-in thermal wave imaging. In this technique, pioneered earlier at Wayne State University, a periodic heat source is applied to the surface of the material, and synchronous, phase-sensitive detection of the IR radiation from that surface is used to determine the effects of thermal wave propagation to subsurface features, and the effects of reflected thermal waves from those features on the observed IR radiation from the surface. The rationale for re-visiting this technique is the availability of the focal-plane-array IR camera, with its "snapshot" capability, its high spatial resolution, and its high pixel rate. A lock-in imaging method is developed for use with this camera, which can be used at frequencies that considerably exceed the maximum frame rate, with illustrative applications to characterize the thermal properties of printed circuits and electronic packages.

Prediction of hydrocarbon surface seepage potential using infiltrometer data

NASA Astrophysics Data System (ADS)

Connors, J. J.; Jackson, J. L.; Engle, R. A.; Connors, J. L.

2017-12-01

Environmental regulations addressing above-ground storage tank (AST) spill control activities typically require owners/operators to demonstrate that local soil permeability values are low enough to adequately contain released liquids while emergency-response procedures are conducted. Frequently, geotechnical borings and soil samples/analyses, and/or monitoring well slug-test analyses, are used to provide hydraulic conductivity data for the required calculations. While these techniques are useful in assessing hydrological characteristics of the subsurface, they do not always assess the uppermost surface soil layer, where the bulk of the containment can occur. This layer may have been subject to long-term permeability-reduction by activities such as compaction by vehicular and foot traffic, micro-coatings by hydrophobic pollutants, etc. This presentation explores the usefulness of dual-ring infiltrometers, both in field and bench-scale tests, to rapidly acquire actual hydraulic conductivity values of surficial soil layers, which can be much lower than subsurface values determined using more traditional downhole geotechnical and hydrogeological approaches.

Subsurface Structure Mapping Using Geophysical Data in Candi Umbul-Telomoyo, Magelang, Central Java, Indonesia

NASA Astrophysics Data System (ADS)

Affanti, A. P.; Prastyani, E.; Maghfira, P. D.; Niasari, S. W.

2018-04-01

Candi Umbul warm spring is one of the manifestations in the Telomoyo geothermal prospect area. A geophysical survey had been conducted using VLF (Very Low Frequency) EM, VLF R and magnetic methods in the Candi Umbul-Telomoyo. VLF EM, VLF R and magnetic data were aimed to image the conductivity and magnetic anomalies distribution of the subsurface beneath the Candi Umbul-Telomoyo. VLF EM data had been mapped with Karous-Hjelt filter and analysed by tipper analysis, VLF R data had been modelled using 2layinv and analysed using impedance analysis. On the other hand, magnetic data processing was done with upward continuation. The Karous-Hjelt filter and 2layinv models show the highest conductivity distribution that located at 4800-5000 m were correlated with tipper and impedance analyses. In addition, the high-low magnetic contrast from the quantitative magnetic data interpretation indicates a fault (which could be a fluid pathway) which is closed to the Candi Umbul warm spring manifestation.

Pluto's Volatile Transport

NASA Astrophysics Data System (ADS)

Young, Leslie

2012-10-01

Pluto's varying subsolar latitude and heliocentric distance leads to large variations in the surface volatile distribution and surface pressure. I present results of new volatile transport models (Young 2012a, b). The models include insolation, thermal emission, subsurface conduction, heating of a volatile slab, internal heat flux, latent heat of sublimation, and strict global mass balance. Numeric advances include initial conditions that allow for rapid convergence, efficient computation with matrix arithmetic, and stable Crank-Nicholson timesteps for both bare and volatile-covered areas. Runs of the model show six distinct seasons on Pluto. (1) As Pluto approaches perihelion, the volatiles on the old winter pole (the Rotational North Pole, RNP) becomes more directly illuminated , and the pressure and albedo rise rapidly. (2) When a new ice cap forms on the Rotational South Pole, RSP, volatiles are exchanged between poles. The pressure and albedo change more slowly. (3) When all volatiles have sublimed from the RNP, the albedo and pressure drop rapidly. (4-6) A similar pattern is repeated near aphelion with a reversal of the roles and the poles. I will compare results with earlier Pluto models of Hansen and Paige (1996), show the dependence on parameters such as substrate inertia, and make predictions for the New Horizons flyby of Pluto in 2015. This work was supported, in part, by funding from NASA Planetary Atmospheres Grant NNG06GF32G and the Spitzer project (JPL research support Agreement 1368573). Hansen, C. J. and D. A. Paige 1996. Seasonal Nitrogen Cycles on Pluto. Icarus 120, 247-265. Young, L. A. 2012a. Volatile transport on inhomogeneous surfaces: I - Analytic expressions, with application to Pluto’s day. Icarus, in press Young, L. A. 2012b. Volatile transport on inhomogeneous surfaces: II. Numerical calculations, with application to Pluto's season. In preparation.

Enceladus' Geysers and Small-scale Thermal Hot Spots: Spatial Correlations and Implications

NASA Astrophysics Data System (ADS)

Porco, C.; Helfenstein, P.; Goguen, J.

2016-12-01

The geysering south polar terrain (SPT) of Enceladus has been a major focus of the Cassini mission ever since Cassini's first sighting of it in images taken in early 2005 (1). A high resolution imaging survey of the region conducted over the course of seven years resulted in the identification of 100 geysers erupting from the four main fractures crossing the SPT (2). The Cassini Visual and Infrared Mapping Spectrometer (VIMS) detected enhanced thermal emission arising from these fractures and taking the form of small-scale ( ≤ 10 meter) discrete spots (3,4). Four of these hot spot observations have already been spatially associated with four geysers on the Baghdad Sulcus fracture (2). The inferred spatial correlation and small size of each hot spot eliminated shear heating along the near-surface walls of the fractures as the source of the heat and erupting materials. Instead, it was concluded that condensation of vapor (and liquid), and the deposition of latent heat, on the near-surface vent walls, and the subsequent conduction of that heat to the surface, was the source of the observed thermal emission. This indicated that the hot spots are the secondary signature of a geyser eruption process deeply rooted in the moon's sub-surface liquid water reservoir (2). We extend the examination of these relationships to include seven additional VIMS observations of hot spots. At the present time, we have associated a total of 11 VIMS hot spot observations with 13 (maybe 14) geysers distributed over all four tiger stripe fractures. It's not uncommon for the locations of multiple (often two but sometimes three) surveyed geysers to overlap within estimated uncertainties. This can occur when they have different 3D orientations, making them identifiable in our 2014 survey as distinct features; However, the raw, thermally unmodeled VIMS maps, with their (relatively) coarse resolution, may register at that location only one corresponding hot spot. It is also possible that closely overlapping clusters of geysers in the survey represent a single geyser that changes its direction over the course of an Enceladus orbit as its vent widens and narrows with the diurnally varying normal stresses. Nonetheless, future thermal modeling of these VIMS hot spots should help constrain the conditions in the near-surface vents from which the geysers erupt.

Estimation of subsurface formation temperature in the Yangtze area, South China: implications for shale gas generation and preservation

NASA Astrophysics Data System (ADS)

Liu, S.; Hao, C.; Li, X.; Xu, M.

2015-12-01

Temperature is one key parameter for hydrocarbon generation and preservation, also playing important role in geothermal energy assessment;however, accurate regional temperature pattern is still challenging, owing to a lack of data coverage and data quality as well. The Yangtze area, located in the South China, is considered as the most favorable target for shale gas resource exploration in China, and attracts more and more attention recently. Here we used the newly acquired steady-state temperature loggings, reliable Drilling Stem Test temperature data available and thermal properties, estimated the subsurface temperature-at-depth for the Yangtze area. Results show that the geothermal gradient ranges between 17 K/m and 74K/m, mainly falling into 20~30K/m, with a mean of 24 K/m; heat flow varies from 25 mW/m2 to 92 mW/m2, with a mean of 65 mW/m2. For the estimated temperature-at-depth, it is about 20~50 ℃ at the depth of 1000m, 50~80℃ for that at 2000m; while the highest temperature can be up to 110℃ at 3000m depth. Generally, the present-day geothermal regime of the Yangtze area is characterized by high in the northeast, low in the middle and localized high again in the southwest, and this pattern is well consistent with the tectono-thermal processes occurred in the area. Due to Cenozoic crustal extension in the northeastern Yangtze area, magmatism is prevailed, accounting for the high heat flow observed. Precambrian basement exists in the middle Yangtze area, such as the Xuefeng and Wuling Mountains, heat flow and subsurface temperature accordingly show relatively low as well. While for the southwestern Yangtze area, especially Yunnan and western Sichuan provinces, localized Cenozoic magmatism and tectonic activities are available, which is attributed to the high geothermal regime there. Considering the Paleozoic intensive tectonic deformation in the Yangtze area, tectonically stable area is prerequisite for shale gas preservation. Geothermal regime analysis presented here, indicates that the middle and northwestern Yangtze areas are favorable for shale gas preservation. In addition, the localized high temperature within the generally low geothermal background is also suggested here as a possible beneficial condition for shale gas generation.

The Effects of Tidal Dissipation on the Thermal Evolution of Triton

NASA Astrophysics Data System (ADS)

Gaeman, J.; Hier-Majumder, S.; Roberts, J. H.

2009-12-01

This work explores the coupled structural, thermal, and orbital evolution of Neptune's icy satellite, Triton. Recent geyser activity, ridge formation, and volatile transport, observed on Triton's surface, indicate possible activity within Triton's interior [1,2]. Triton is hypothesized to have been captured from an initially heliocentric orbit. During the circularization of Triton's orbit following its capture by Neptune, intense tidal heating likely contributed to the formation of a subsurface ocean [3]. Although the time of Triton's capture is not exactly known, it is likely that the event took place earlier in the history of our solar system, when the probability of binary capture was higher [4, 5]. This work examines the thermal evolution of Triton by employing a coupled tidal and two-phase thermal evolution model, for both an early and late capture scenario. Thermal evolution of a solid crust underlain by an H2O-NH3 mushy layer is driven by the evolution of tidal heating, as Triton's orbital eccentricity evolves following its capture. The governing equations for tidal heating are solved using the propagator matrix method [6, 7], while the governing equation for the coupled crust-multiphase layer thermal evolution were numerically solved using a finite volume discretization. The results indicate that the existence of a subsurface ocean is strongly dependent on ammonia content as larger concentrations of ammonia influence liquidus temperature and density contrast between solid and liquid phases [8]. Preliminary results indicate that an ocean likely exists for compositions containing a relatively high percentage of ammonia for both early and late capture of the satellite. In contrast, the subsurface ocean freezes completely for lower ammonia content. [1] Brown, R. H., Kirk, R. L. (1994). Journal of Geophysical Research 99, 1965-981. [2] Prockter, L. M., Nimmo, F., Pappalardo, R. T. (2005). Geophysical Research Letters 32, L14202. [3] Ross, M. N., Schubert, G. (1990). Geophysical Research Letters 17, 1749-752. [4] Agnor, C. B., Hamilton, D. P. (2006). Nature 441, 192-94. [5] Schenk, P. M., Zahnle, K. (2007). Icarus 192, 135-49. [6] Roberts, J. H., Nimmo, F. (2008). Icarus 194, 675-689. [7] Sabadini, R., Vermeersen, B., (2004). Global Dynamics of the Earth. Kluwer Academic Publishers. [8] Hogenboom, D. L., Kargel, J. S., Concolmagno, G. J., Holden, T. C., Lee, L., Buyyounouski, M. (1997). Icarus 128, 171-80.

Effects of the Extended Water Retention Curve on Coupled Heat and Water Transport in the Vadose Zone

NASA Astrophysics Data System (ADS)

Yang, Z.; Mohanty, B.

2017-12-01

Understanding and simulating coupled heat and water transfer appropriately in the shallow subsurface is of vital significance for accurate prediction of soil evaporation that would improve the coupling between land surface and atmosphere. The theory of Philip and de Vries (1957) and its extensions (de Vries, 1958; Milly, 1982), although physically incomplete, are still adopted successfully to describe the coupled heat and water movement in field soils. However, the adsorptive water retention, which was ignored in Philip and de Vries theory and its extensions for characterizing soil hydraulic parameters, was shown to be non-negligible for soil moisture and evaporation flux calculation in dry field soils based on a recent synthetic analysis (Mohanty and Yang, 2013). In this study, we attempt to comprehensively investigate the effects of full range water retention curve on coupled heat and water transport simulation with a focus on soil moisture content, temperature and soil evaporative flux, based on two synthetic (sand and loam) and two field sites (Riverside, California and Audubon, Arizona) analysis. The results of synthetic sand and loam numerical modeling showed that when neglecting the adsorptive water retention, the resulting simulated soil water content would be larger, and the evaporative flux would be lower, respectively, compared to that obtained by the full range water retention curve mode. The simulated temperature did not show significant difference with or without accounting for adsorptive water retention. The evaporation underestimation when neglecting the adsorptive water retention is mainly caused by isothermal hydraulic conductivity underprediction. These synthetic findings were further corroborated by the Audubon, Arizona field site experimental results. The results from Riverside, California field experimental site showed that the soil surface can reach very dry status, although the soil profile below the drying front is not dry, which also to some extent justifies the necessity of employing full range water retention function in such generally not quite dry scenarios.

Satellite Tidal Magnetic Signals Constrain Oceanic Lithosphere-Asthenosphere Boundary Earth Tomography with Tidal Magnetic Signals

NASA Technical Reports Server (NTRS)

Grayver, Alexander V.; Schnepf, Neesha R.; Kuvshinov, Alexey V.; Sabaka, Terence J.; Chandrasekharan, Manoj; Olsen, Niles

2016-01-01

The tidal flow of electrically conductive oceans through the geomagnetic field results in the generation of secondary magnetic signals, which provide information on the subsurface structure. Data from the new generation of satellites were shown to contain magnetic signals due to tidal flow; however, there are no reports that these signals have been used to infer subsurface structure. Here we use satellite-detected tidal magnetic fields to image the global electrical structure of the oceanic lithosphere and upper mantle down to a depth of about 250 km. The model derived from more than 12 years of satellite data reveals an Approximately 72 km thick upper resistive layer followed by a sharp increase in electrical conductivity likely associated with the lithosphere-asthenosphere boundary, which separates colder rigid oceanic plates from the ductile and hotter asthenosphere.

Satellite tidal magnetic signals constrain oceanic lithosphere-asthenosphere boundary

PubMed Central

Grayver, Alexander V.; Schnepf, Neesha R.; Kuvshinov, Alexey V.; Sabaka, Terence J.; Manoj, Chandrasekharan; Olsen, Nils

2016-01-01

The tidal flow of electrically conductive oceans through the geomagnetic field results in the generation of secondary magnetic signals, which provide information on the subsurface structure. Data from the new generation of satellites were shown to contain magnetic signals due to tidal flow; however, there are no reports that these signals have been used to infer subsurface structure. We use satellite-detected tidal magnetic fields to image the global electrical structure of the oceanic lithosphere and upper mantle down to a depth of about 250 km. The model derived from more than 12 years of satellite data reveals a ≈72-km-thick upper resistive layer followed by a sharp increase in electrical conductivity likely associated with the lithosphere-asthenosphere boundary, which separates colder rigid oceanic plates from the ductile and hotter asthenosphere. PMID:27704045