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Sample records for ground effects simulator

  1. SIMULATION OF WAKE VORTEX AIRCRAFT IN GROUND EFFECT

    Directory of Open Access Journals (Sweden)

    Pamfil ŞOMOIAG

    2011-03-01

    Full Text Available The problem developed in this paper is encountered in airplane aerodynamics and concernsthe influence of long life longitudinal wake vortices generated by wing tips or by external obstaclessuch as reactors or landing gears. More generally it concerns 3D bodies of finite extension in crossflow. At the edge of such obstacles, longitudinal vortices are created by pressure differences inside theboundary layers and rotate in opposite senses. It can constitute a danger to another aircraft that fliesin this wake, especially during takeoff and landing. In this case the wake vortex trajectories andstrengths are altered by ground interactions. This study presents the results of a Large EddySimulation of wake vortex in ground effect providing the vorticity flux behavior.

  2. Dynamic Ground Effects Simulation Using OVERFLOW-D

    Science.gov (United States)

    Dwyer, Bill

    1999-01-01

    This presentation is broken into 5 logical sections. The Background Information section describes the technical issues being address by this study. The Approach section describes the organization of the contract effort which was laid out as the most effective means of quantifying, with validated methods, the magnitude of dynamic ground effects for the TCA (Technology Concept Aircraft) configuration. The Validation Case section describes the analysis of the XB-70 configuration in both static and dynamic ground effect, with comparisons to wind tunnel and flight test data. The TCA Analysis section then describes the application of the same codes and methodologies to the TCA in both static and dynamic ground effect. Comparisons are made between the static and dynamic, as well as to early static data from a recent wind tunnel test on the TCA configuration. Finally, the work to date is summarized and the future direction of this study is outlined.

  3. Application of Ground Phosphate Rock to Diminish the Effects of Simulated Acid Rain of Soil Properties

    Institute of Scientific and Technical Information of China (English)

    DONGYUAN-YAN; LIXUE-YUAN

    1992-01-01

    The effects of simulated acid rain retained in soil on the properties of acid soil and its diminishing by application of ground phosphate rock were investigated by using the sorption method.Results show as follows:(1)For yellow brown soil,the effect of simulated acid rain on the properties of soil with a pH value of 5.9 was relatively small,except a great quantity of acid rain deposited on it.(2) for red soil,the effect of simulated acid rain on the properties of soil was significant.With the increase of the amount of acid deposition,the pH value of soil was declined,but the contents of exchangeable H+,Al3+ and Mn2+ and the amount of SO41- retention were increased.(3) Many properties of acid soils could be improved by applying ground phosphate rock.For example,pH value of soils and the amounts of available P and exchangeable Ca2+ and Mg2+ were increased,and the amounts of exchangeable H+ and Al3+ and SO42- retained was reduced.The application of ground posphate rock could effctively diminish the pollution of acid rain to soil.

  4. 2.5D Simulation of basin-edge effects on the ground motion characteristics

    Indian Academy of Sciences (India)

    J P Narayan

    2003-09-01

    The effects of basin-edge and soil velocity on the ground motion characteristics have been simulated using 2.5D modeling. One of the most significant advantages of the 2.5D simulation is that 3D radiation pattern can be generated in a 2D numerical grid using double-couple shear dislocation source. Further, 2.5D numerical modeling avoids the extensive computational cost of 3D modeling. The responses of basin-edge model using different soil velocities revealed that surface waves were generated near the edge of the basin and propagated normal to the edge, towards the basin. Further, the results depict increase of amplification, duration and surface wave generation with the decrease in soil velocity.

  5. Self contamination effects in the TAUVEX UV Telescope: Ground testing and computer simulation

    Science.gov (United States)

    Lifshitz, Y.; Noter, Y.; Grossman, E.; Genkin, L.; Murat, M.; Saar, N.; Blasberger, A.

    1994-01-01

    The contamination effects due to outgassing from construction materials of the TAUVEX (Tel Aviv University UV Telescope) were evaluated using a combination of ground testing and computer simulations. Tests were performed from the material level of the system level including: (1) High sensitivity CVCM(10(exp -3 percent) measurements of critical materials. (2) Optical degradation measurements of samples specially contaminated by outgassing products at different contamination levels. (3) FTIR studies of chemical composition of outgassed products on above samples. (4) High resolution AFM studies of surface morphology of contaminated surfaces. The expected degradation of TAUVEX performance in mission was evaluated applying a computer simulation code using input parameters determined experimentally in the above tests. The results have served as guidelines for the proper selection of materials, cleanliness requirements, determination of the thermal conditions of the system and bakeout processes.

  6. Stochastic ground motion simulation

    Science.gov (United States)

    Rezaeian, Sanaz; Xiaodan, Sun; Beer, Michael; Kougioumtzoglou, Ioannis A.; Patelli, Edoardo; Siu-Kui Au, Ivan

    2014-01-01

    Strong earthquake ground motion records are fundamental in engineering applications. Ground motion time series are used in response-history dynamic analysis of structural or geotechnical systems. In such analysis, the validity of predicted responses depends on the validity of the input excitations. Ground motion records are also used to develop ground motion prediction equations(GMPEs) for intensity measures such as spectral accelerations that are used in response-spectrum dynamic analysis. Despite the thousands of available strong ground motion records, there remains a shortage of records for large-magnitude earthquakes at short distances or in specific regions, as well as records that sample specific combinations of source, path, and site characteristics.

  7. Simulation of spatially varying ground motions including incoherence, wave‐passage and differential site‐response effects

    DEFF Research Database (Denmark)

    Konakli, Katerina; Der Kiureghian, Armen

    2012-01-01

    A method is presented for simulating arrays of spatially varying ground motions, incorporating the effects of incoherence, wave passage, and differential site response. Non‐stationarity is accounted for by considering the motions as consisting of stationary segments. Two approaches are developed....... In the first, simulated motions are consistent with the power spectral densities of a segmented recorded motion and are characterized by uniform variability at all locations. Uniform variability in the array of ground motions is essential when synthetic motions are used for statistical analysis of the response...

  8. Simulated effects of proposed ground-water pumping in 17 basins of east-central and southern Nevada

    Science.gov (United States)

    Schaefer, D.H.; Harrill, J.R.

    1995-01-01

    The Las Vegas Valley Water District filed 146 applications in 1989 to pump about 180,800 acre- ft/yr in 17 basins for use in Las Vegas Valley. A previously constructed, two-layer computer model of the carbonate-rock province area was configured to simulate transient conditions and used to develop first approximations of the possible effects of these withdrawals. Simulations were made using the phased pumping schedule proposed by the water district. Ground-water-level declines of several hundred feet could ultimately develop in the basins scheduled to supply most of the pumped ground water. Simulated declines in the carbonate-rock aquifer were somewhat larger than simulated declines in the overlying basin-fill deposits. Decreases in simulated regional spring flow were shown in several cells including those representing the Muddy River Springs, Hiko-Crystal-Ash spring area, and the Ash Meadows spring area. Model simulations show flow decreases of about 11 percent, 14 percent, and 2 percent, respectively, at these springs after almost 100 years of pumping. Simulated evapotranspiration also decreased in many basins, with the largest decreases occurring in the basins where ground-water withdrawals were greatest. These basins include Railroad, Spring, and Snake Valleys. The largest decrease in simulated evapotranspiration occurred in Railroad Valley, 64 percent after almost 100 years of pumpage. Model-sensitivity tests indicate that long-term results were relatively insensitive to variations in values used for aquifer storage. The adequacy of the model to simulate the effects of this proposed pumping will remain untested until actual pumping stresses have been in place long enough to cause measurable effects within the system.

  9. Ground-Water Resources in Kaloko-Honokohau National Historical Park, Island of Hawaii, and Numerical Simulation of the Effects of Ground-Water Withdrawals

    Science.gov (United States)

    Oki, Delwyn S.; Tribble, Gordon W.; Souza, William R.; Bolke, Edward L.

    1999-01-01

    Within the Kaloko-Honokohau National Historical Park, which was established in 1978, the ground-water flow system is composed of brackish water overlying saltwater. Ground-water levels measured in the Park range from about 1 to 2 feet above mean sea level, and fluctuate daily by about 0.5 to 1.5 feet in response to ocean tides. The brackish water is formed by mixing of seaward flowing fresh ground water with underlying saltwater from the ocean. The major source of fresh ground water is from subsurface flow originating from inland areas to the east of the Park. Ground-water recharge from the direct infiltration of precipitation within the Park area, which has land-surface altitudes less than 100 feet, is small because of low rainfall and high rates of evaporation. Brackish water flowing through the Park ultimately discharges to the fishponds in the Park or to the ocean. The ground water, fishponds, and anchialine ponds in the Park are hydrologically connected; thus, the water levels in the ponds mark the local position of the water table. Within the Park, ground water near the water table is brackish; measured chloride concentrations of water samples from three exploratory wells in the Park range from 2,610 to 5,910 milligrams per liter. Chromium and copper were detected in water samples from the three wells in the Park and one well upgradient of the Park at concentrations of 1 to 5 micrograms per liter. One semi-volatile organic compound, phenol, was detected in water samples from the three wells in the Park at concentrations between 4 and 10 micrograms per liter. A regional, two-dimensional (areal), freshwater-saltwater, sharp-interface ground-water flow model was used to simulate the effects of regional withdrawals on ground-water flow within the Park. For average 1978 withdrawal rates, the estimated rate of fresh ground-water discharge to the ocean within the Park is about 6.48 million gallons per day, or about 3 million gallons per day per mile of coastline

  10. IMF By effects on ground magnetometer response to increased solar wind dynamic pressure derived from global MHD simulations

    Science.gov (United States)

    Ozturk, Dogacan Su; Zou, Shasha; Slavin, James A.

    2017-05-01

    During sudden solar wind dynamic pressure enhancements, the magnetosphere undergoes rapid compression resulting in a reconfiguration of the global current systems, most notably the field-aligned currents (FACs). Ground-based magnetometers are traditionally used to study such compression events. However, factors affecting the polarity and magnitude of the ground-based magnetic perturbations are still not well understood. In particular, interplanetary magnetic field (IMF) By is known to create significant asymmetries in the FAC patterns. We use the University of Michigan Block Adaptive Tree Roe Upwind Scheme (BATS'R'US) magnetohydrodynamic code to investigate the effects of IMF By on the global variations of ground magnetic perturbations during solar wind dynamic pressure enhancements. Using virtual magnetometers in three idealized simulations with varying IMF By, we find asymmetries in the peak amplitude and magnetic local time of the ground magnetic perturbations during the preliminary impulse (PI) and the main impulse (MI) phases. These asymmetries are especially evident at high-latitude ground magnetometer responses where the peak amplitudes differ by 50 nT at different locations. We show that the FACs related with the PI are due to magnetopause deformation, and the FACs related with the MI are generated by vortical flows within the magnetosphere, consistent with other simulation results. The perturbation FACs due to pressure enhancements and their magnetospheric sources do not differ much under different IMF By polarities. However, the conductance profile affected by the superposition of the preexisting FACs and the perturbation FACs including their closure currents is responsible for the magnitude and location asymmetries in the ground magnetic perturbations.

  11. Engineering applications of strong ground motion simulation

    Science.gov (United States)

    Somerville, Paul

    1993-02-01

    The formulation, validation and application of a procedure for simulating strong ground motions for use in engineering practice are described. The procedure uses empirical source functions (derived from near-source strong motion recordings of small earthquakes) to provide a realistic representation of effects such as source radiation that are difficult to model at high frequencies due to their partly stochastic behavior. Wave propagation effects are modeled using simplified Green's functions that are designed to transfer empirical source functions from their recording sites to those required for use in simulations at a specific site. The procedure has been validated against strong motion recordings of both crustal and subduction earthquakes. For the validation process we choose earthquakes whose source models (including a spatially heterogeneous distribution of the slip of the fault) are independently known and which have abundant strong motion recordings. A quantitative measurement of the fit between the simulated and recorded motion in this validation process is used to estimate the modeling and random uncertainty associated with the simulation procedure. This modeling and random uncertainty is one part of the overall uncertainty in estimates of ground motions of future earthquakes at a specific site derived using the simulation procedure. The other contribution to uncertainty is that due to uncertainty in the source parameters of future earthquakes that affect the site, which is estimated from a suite of simulations generated by varying the source parameters over their ranges of uncertainty. In this paper, we describe the validation of the simulation procedure for crustal earthquakes against strong motion recordings of the 1989 Loma Prieta, California, earthquake, and for subduction earthquakes against the 1985 Michoacán, Mexico, and Valparaiso, Chile, earthquakes. We then show examples of the application of the simulation procedure to the estimatation of the

  12. Geohydrology of the Central Oahu, Hawaii, Ground-Water Flow System and Numerical Simulation of the Effects of Additional Pumping

    Science.gov (United States)

    Oki, Delwyn S.

    1998-01-01

    A two-dimensional, finite-difference, ground-water flow model was developed for the central Oahu flow system, which is the largest and most productive ground-water flow system on the island. The model is based on the computer code SHARP which simulates both freshwater and saltwater flow. The ground-water model was developed using average pumping and recharge conditions during the 1950's, which was considered to be a steady-state period. For 1950's conditions, model results indicate that 62 percent (90.1 million gallons per day) of the discharge from the Schofield ground-water area flows southward and the remaining 38 percent (55.2 million gallons per day) of the discharge from Schofield flows northward. Although the contribution of recharge from infiltration of rainfall and irrigation water directly on top of the southern and northern Schofield ground-water dams was included in the model, the distribution of natural discharge from the Schofield ground-water area was estimated exclusive of the recharge on top of the dams. The model was used to investigate the long-term effects of pumping under future land-use conditions. Future recharge was conservatively estimated by assuming no recharge associated with agricultural activities. Future pumpage used in the model was based on the 1995-allocated rates. Model results indicate that the long-term effect of pumping at the 1995-allocated rates will be a reduction of water levels from present (1995) conditions in all ground-water areas of the central Oahu flow system. In the Schofield ground-water area, model results indicate that water levels could decline about 30 feet from the 1995 water-level altitude of about 275 feet. In the remaining ground-water areas of the central Oahu flow system, water levels may decline from less than 1 foot to as much as 12 feet relative to 1995 water levels. Model results indicate that the bottoms of several existing deep wells in northern and southern Oahu extend below the model

  13. Computer simulations of comet- and asteroidlike bodies passing through the Venusian atmosphere: Preliminary results on atmospheric and ground shock effects

    Science.gov (United States)

    Roddy, D.; Hatfield, D.; Hassig, P.; Rosenblatt, M.; Soderblom, L.; Dejong, E.

    1992-01-01

    We have completed computer simulations that model shock effects in the venusian atmosphere caused during the passage of two cometlike bodies 100 m and 1000 m in diameter and an asteroidlike body 10 km in diameter. Our objective is to examine hypervelocity-generated shock effects in the venusian atmosphere for bodies of different types and sizes in order to understand the following: (1) their deceleration and depth of penetration through the atmosphere; and (2) the onset of possible ground-surface shock effects such as splotches, craters, and ejecta formations. The three bodies were chosen to include both a range of general conditions applicable to Venus as well as three specific cases of current interest. These calculations use a new multiphase computer code (DICE-MAZ) designed by California Research & Technology for shock-dynamics simulations in complex environments. The code was tested and calibrated in large-scale explosion, cratering, and ejecta research. It treats a wide range of different multiphase conditions, including material types (vapor, melt, solid), particle-size distributions, and shock-induced dynamic changes in velocities, pressures, temperatures (internal energies), densities, and other related parameters, all of which were recorded in our calculations.

  14. Sedimentary basin effects in Seattle, Washington: Ground-motion observations and 3D simulations

    Science.gov (United States)

    Frankel, Arthur; Stephenson, William; Carver, David

    2009-01-01

    Seismograms of local earthquakes recorded in Seattle exhibit surface waves in the Seattle basin and basin-edge focusing of S waves. Spectral ratios of Swaves and later arrivals at 1 Hz for stiff-soil sites in the Seattle basin show a dependence on the direction to the earthquake, with earthquakes to the south and southwest producing higher average amplification. Earthquakes to the southwest typically produce larger basin surface waves relative to S waves than earthquakes to the north and northwest, probably because of the velocity contrast across the Seattle fault along the southern margin of the Seattle basin. S to P conversions are observed for some events and are likely converted at the bottom of the Seattle basin. We model five earthquakes, including the M 6.8 Nisqually earthquake, using 3D finite-difference simulations accurate up to 1 Hz. The simulations reproduce the observed dependence of amplification on the direction to the earthquake. The simulations generally match the timing and character of basin surface waves observed for many events. The 3D simulation for the Nisqually earth-quake produces focusing of S waves along the southern margin of the Seattle basin near the area in west Seattle that experienced increased chimney damage from the earthquake, similar to the results of the higher-frequency 2D simulation reported by Stephenson et al. (2006). Waveforms from the 3D simulations show reasonable agreement with the data at low frequencies (0.2-0.4 Hz) for the Nisqually earthquake and an M 4.8 deep earthquake west of Seattle.

  15. The effect of randomly earthed ground wires on PLC transmission; A simulation experiment

    Energy Technology Data Exchange (ETDEWEB)

    Brandao Faria, J.A.; Borges da Silva, J.F. (Centro de Electrotecnia da Universidade Tecnica de Lisboa, Instituto Superior Tecnico, Dept. of Electrical Engineering, 1096 Lisboa Codex (PT))

    1990-10-01

    Power line ground wires are discretely bonded to earth along the line at each tower. When the spacing between towers is constant and approaches a multiple of one half wavelength at the operating frequency, abrupt variations in the propagation parameters occur, that would affect carrier transmission performance at the vicinity of certain critical frequencies. In practice the spacing between towers is not exactly constant and one may wish to know the result of taking this circumstance into account. The analysis and numerical results presented in this paper show that even slight random perturbations of line periodicity are sufficient to render unnoticeable any sharp variations in attenuation, velocity and surge impedance, one might be led to expect from the analysis of the strictly periodic case.

  16. Ground Based Simulation Evaluation of the Effects of Time Delays and Motion on Rotorcraft Handling Qualities

    Science.gov (United States)

    1992-01-01

    Simulation Facility B. MATH MODEL The mathematical model for the rotorcraft was a generic, uncoupled stability-derivative model that has been used for...5 1 2 3 4 5 1 2 3 4 5 Affiftu VCR Alti~de VCR Afttiue VCR a) Ho~w b) Vedical TAns/alon#)Pkue 5 5 5 12 "-i " -2 _ 3 3 3 3LC- L7 3______ i -1 1 1 eI 1...13-1 - 13-62. A-2. McRuer, D. T., and E. S. Krendel, Mathematical Models of Human Pilot Behavior. AGARD AG-188, Jan. 1974. A-3. Peters, Richard A

  17. Study on the Effect of Ground Heat Storage by Solar Heat Using Numerical Simulation

    Directory of Open Access Journals (Sweden)

    Jin-Hwan Oh

    2015-12-01

    Full Text Available Recently, energy storage techniques using renewable energy efficiently have attracted considerable attention. However, there are several problems when using renewable energy. In the case of solar energy, the energy production time is different from the consumption time, and the use of geothermal energy has high investment costs. In order to solve these problems, it is essential to develop high-efficiency systems using both solar and geothermal energy simultaneously and efficiently. Thus, in this study, the performance of underground heat storage of solar energy was examined by simulation using models of underground heat transfer and heat exchange for the development of an integrated hybrid system exploiting both geothermal and solar energy. As a result, the heat extraction performance was determined to be up to 72.75 W/m. As a result, in Kagoshima, the most southern area in Korea, a case of six hour heat storage operation achieved the highest heat exchange rate of 72.75 W/m, which is approximately 105% higher than the case of operation without heat storage.

  18. Effects of simulated genu valgum and genu varum on ground reaction forces and subtalar joint function during gait.

    Science.gov (United States)

    Van Gheluwe, Bart; Kirby, Kevin A; Hagman, Friso

    2005-01-01

    The mechanical effects of genu valgum and varum deformities on the subtalar joint were investigated. First, a theoretical model of the forces within the foot and lower extremity during relaxed bipedal stance was developed predicting the rotational effect on the subtalar joint due to genu valgum and varum deformities. Second, a kinetic gait study was performed involving 15 subjects who walked with simulated genu valgum and genu varum over a force plate and a plantar pressure mat to determine the changes in the ground reaction force vector within the frontal plane and the changes in the center-of-pressure location on the plantar foot. These results predicted that a genu varum deformity would tend to cause a subtalar pronation moment to increase or a supination moment to decrease during the contact and propulsion phases of walking. With genu valgum, it was determined that during the contact phase a subtalar pronation moment would increase, whereas in the early propulsive phase, a subtalar supination moment would increase or a pronation moment would decrease. However, the current inability to track the spatial position of the subtalar joint axis makes it difficult to determine the absolute direction and magnitudes of the subtalar joint moments.

  19. MONTE CARLO SIMULATION FOR MODELING THE EFFECT OF GROUND SEGMENT LOCATION ON IN-ORBIT RESPONSIVENESS OF LEO SUNSYNCHRONOUS SATELLITE S

    Institute of Scientific and Technical Information of China (English)

    M. Navabi; Hossein Bonyan Khamseh

    2011-01-01

    Responsiveness is a challenge for space systems to sustain competitive advantage over alternate non-spaceborne technologies.For a satellite in its operational orbit,in-orbit responsiveness is defined as the capability of the satellite to respond to a given demand in a timely manner.In this paper,it is shown that Average Wait Time (AWT) to pick up user demand from ground segment is the appropriate metric to evaluate the effect of ground segment location on in-orbit responsiveness of Low Earth Orbit (LEO) sunsynchronous satellites.This metric depends on pattern of ground segment access to satellite and distribution of user demands in time domain.A mathematical model is presented to determine pattern of ground segment access to satellite and concept of cumulative distribution function is used to simulate distribution of user demands for markets with different total demand scenarios.Monte Carlo simulations are employed to take account of uncertainty in distribution and total volume of user demands.Sampling error and standard deviation are used to ensure validity of AWT metric obtained from Monte Carlo simulations.Incorporation of the proposed metric in the ground segment site location process results in more responsive satellite systems which,in turn,lead to greater customer satisfaction levels and attractiveness of spaceborne systems for different applications.Finally,simulation results for a case study are presented.

  20. SCEC Broadband Platform Strong Ground Motion Simulations

    Science.gov (United States)

    Kumar, S.; Callaghan, S.; Maechling, P. J.; Olsen, K. B.; Archuleta, R. J.; Somerville, P. G.; Graves, R. W.; Jordan, T. H.; Broadband Platform Working Group

    2011-12-01

    The Southern California Earthquake Center (SCEC) Broadband Platform is a collaborative software development project involving SCEC researchers, graduate students, and the SCEC Community Modeling Environment. The goal of the SCEC Broadband Simulation Platform is to generate broadband (0-10 Hz) ground motions for earthquakes using deterministic low-frequency and stochastic high-frequency simulations. SCEC developers have integrated complex scientific modules for rupture generation, low-frequency deterministic seismogram synthesis, high-frequency stochastic seismogram synthesis, and non-linear site effects calculation into a system that supports easy on-demand computation of broadband seismograms. The SCEC Broadband platform has two primary modes of operation, validation mode, and scenario mode. In validation mode, the earthquake modeling software calculates broadband seismograms for one of three earthquakes, Northridge, Loma Prieta, or Landers at sites with observed strong motion data. Then, the platform calculates goodness of fit measurements that quantify how well the model-based broadband seismograms match the observed seismograms for each event. In scenario mode, the user can specify a scenario earthquake and a list of sites and calculate ground motions at each site for the scenario event. In February 2011, SCEC released Broadband Platform 11.2 as an open-source scientific software distribution. Since that time, we have continued development of the platform by adding a new site response module and new goodness of fit measures by Mayhew and Olsen. Along with a source code distribution of the Broadband Platform, we now offer a virtual software image distribution of the platform to support its use on a variety of computing hardware and operating systems.

  1. Numerical Simulation of Ground Coupling of Low Yield Nuclear Detonation

    Science.gov (United States)

    2010-06-01

    Without nuclear testing, advanced simulation and experimental facilities, such as the National Ignition Facility ( NIF ), are essential to assuring...in planning future experimental work at NIF . 15. NUMBER OF PAGES 93 14. SUBJECT TERMS National Ignition Facility, GEODYN, Ground Coupling...simulation and experimental facilities, such as the National Ignition Facility ( NIF ), are essential to assuring safety, reliability, and effectiveness

  2. Simulation of Ground Winds Time Series

    Science.gov (United States)

    Adelfang, S. I.

    2008-01-01

    A simulation process has been developed for generation of the longitudinal and lateral components of ground wind atmospheric turbulence as a function of mean wind speed, elevation, temporal frequency range and distance between locations. The distance between locations influences the spectral coherence between the simulated series at adjacent locations. Short distances reduce correlation only at high frequencies; as distances increase correlation is reduced over a wider range of frequencies. The choice of values for the constants d1 and d3 in the PSD model is the subject of work in progress. An improved knowledge of the values for zO as a function of wind direction at the ARES-1 launch pads is necessary for definition of d1. Results of other studies at other locations may be helpful as summarized in Fichtl's recent correspondence. Ideally, further research is needed based on measurements of ground wind turbulence with high resolution anemometers at a number of altitudes at a new KSC tower located closer to the ARES-1 launch pad .The proposed research would be based on turbulence measurements that may be influenced by surface terrain roughness that may be significantly different from roughness prior to 1970 in Fichtl's measurements. Significant improvements in instrumentation, data storage end processing will greatly enhance the capability to model ground wind profiles and ground wind turbulence.

  3. 1909 Taipei Earthquake Ground Motion Simulation

    Directory of Open Access Journals (Sweden)

    Yi-Wun Liao

    2016-06-01

    Full Text Available The 1909 Taipei earthquake (M 7.3 occurred beneath the Taipei metropolitan area (TMA causing substantial damage according to the historical literature. According to the hypocenter relocation and tectonic implications provided in a previous study, we simulated ground motions within the TMA using a hybrid simulation method involving the spectral-element method (SEM and the empirical Green’s function method (EGFM. We used the SEM for simulating low-frequency components and the EGFM for simulating high-frequency components. These high and low frequency components were subsequently combined. For the EGFM we used the records from a recent ML 4.9 earthquake (11 October 2013, depth = 143.8 km in the Taipei area as the empirical Green’s function. According to the historical literature, the observed PGA (peak ground acceleration values are 59.2 and 67.0 gal at ancient stations TAP and KEE, with periods of 1.21 and 1.34 s, respectively. By comparing the simulated PGA values at modern stations TAPB and WFSB to the historical documented ones for 12 different models, our result suggests that the 1909 Taipei earthquake was an event with a magnitude of about Mw 7.3 and stress drop of approximately 30 bars, or a smaller equivalent magnitude between Mw 6.8 - 7.3 but with much higher average stress drop of more than 100 bars. For a deep event beneath TMA a larger vertical P-wave motion and longer period shaking wave, as addressed in the historical literature, might be expected with prolonged shaking as found in the simulation. A seismic hazard assessment is necessary for metropolitan Taipei to better understand the long period shaking from deep subduction zone intra plate events.

  4. Numerical Simulation on 3D Multi-element Wings in Ground Effect%三维多段机翼地面效应数值模拟

    Institute of Scientific and Technical Information of China (English)

    秦绪国; 刘沛清; 屈秋林; 徐婕

    2011-01-01

    通过数值模拟方法研究多段机翼的地面效应,采用有限体积法求解质量加权平均Navier-Stokes方程,湍流模型选用Spalart-Allmaras模型,利用运动壁面边界模拟地面的相对运动.计算结果分析表明:随着飞行高度的降低,多段机翼的升力、阻力和低头力矩均减小;迎角、展弦比越大,地面效应越明显,升力损失越大;升力的减小主要是由于地面效应导致机翼下方静压增大的气流通过缝隙进入机翼上表面流场,使得机翼下翼面压力的增加量小于上翼面吸力的减小量;地面效应使机翼上翼面翼尖容易发生分离;翼尖涡沿着展向方向向外移动,机翼诱导阻力减小.该文研究结果可以为大型飞机的增升装置地面效应设计提供参考依据.%A multi-element wing operating in ground effect is investigated numerically. The compressible Navier-Stokes equations are solved by the finite-volume method. An Spalart-AIImaras turbulence model is used. The slipping wall is used to simulate the relative movement of the ground. The results indicate that, with a reduction in height, the lift, drag and node down moment of the multi-element wing decrease. The ground effect is more obvious with greater angles of attack and aspect ratios, and the lift losses also become greater. The effect of the sweep angle on the ground effect is small. The cause of the reduction of lift is that the losses of the suction side of the upper surface are greater than the increases of the pressure side of the lower surface. Adverse gradient increases on the upper surface of the wing in ground effect may cause the flow to separate near the wing tip. Tip vortex goes downstream outward along the span direction, and the induced drag of the wing decreases. The results of the simulation may provide a theoretical basis for the design of height lift devices of large aircraft in ground effect.

  5. Simulated Sea-Level Rise Effects on the Above and Below-Ground Growth of Two Tidal Marsh Plant Species

    Science.gov (United States)

    Schile, L. M.; Callaway, J. C.; Kelly, M.

    2011-12-01

    Sea-level is expected to rise between 55 and 140 cm in the next century and is likely to have significant effects on the distribution and maintenance of tidal wetlands; however, little is known about the effects of increased sea level on Pacific coast tidal marsh vegetation. We initiated a field experiment in March 2011 to examine how increased depth and duration of inundation affect above and below-ground growth of two tidal wetland plant species: Schoenoplectus acutus and S. americanus. PVC planters, referred to as marsh organs, were installed at fixed elevations in channels at two ancient marshes in the San Francisco Bay Estuary: Browns Island and Rush Ranch. Each marsh organ structure is comprised of five rows of three six-inch PVC pipes, with each row 15cm lower than the row above, and was filled with surrounding mudflat sediment. Elevations span 60 cm and were chosen to be lower than the average current elevations of both species at each marsh to reflect projected increases in sea level. Rhizomes were collected from Browns Island, the less-saline site, and were cut to uniform sizes before planting. In every row, each species was grown individually and together. On a monthly basis, plant heights were recorded and pore-water sulfide concentration, salinity, and soil oxidation-reduction potential were measured. Schoenoplectus americanus growth and density significantly decreased with increased inundation at both sites. Schoenoplectus acutus growth was impacted more significantly at lower elevations at Rush Ranch but had little variation in density and growth across elevations at Browns Island. Salinity and sulfide concentrations varied little across elevations within a site but differed between sites. Above and belowground biomass will be collected in September 2011 to measure total annual productivity. The experiment provides basic yet crucial information on the impacts of increased inundation on tidal wetland vegetation and insight into potential changes in

  6. Unsteady propulsion in ground effects

    Science.gov (United States)

    Park, Sung Goon; Kim, Boyoung; Sung, Hyung Jin

    2016-11-01

    Many animals in nature experience hydrodynamic benefits by swimming or flying near the ground, and this phenomenon is commonly called 'ground effect'. A flexible fin flapping near the ground was modelled, inspired by animals swimming. A transverse heaving motion was prescribed at the leading edge, and the posterior parts of the fin were passively fluttering by the fin-fluid interaction. The fin moved freely horizontally in a quiescent flow, by which the swimming speed was dynamically determined. The fin-fluid interaction was considered by using the penalty immersed boundary method. The kinematics of the flexible fin was altered by flapping near the ground, and the vortex structures generated in the wake were deflected upward, which was qualitatively analyzed by using the vortex dipole model. The swimming speed and the thrust force of the fin increased by the ground effects. The hydrodynamic changes from flapping near the ground affected the required power input in two opposite ways; the increased and decreased hydrodynamic pressures beneath the fin hindered the flapping motion, increasing the power input, while the transversely reduced flapping motion induced the decreased power input. The Froude propulsive efficiency was increased by swimming in the ground effects Creative Research Initiatives (No. 2016-004749) program of the National Research Foundation of Korea (MSIP).

  7. Numerical simulation of the effect of wind removing the corona space charge over grounded structures under thunderstorm conditions

    DEFF Research Database (Denmark)

    Vogel, Stephan; Lopez, Javier; Holbøll, Joachim;

    2015-01-01

    that the effectof the removal of the corona space charge by the wind leadsto a higher field strength at the grounded object and, therefore,it becomes easier for it to initiate an upward connecting leadercompared to a situation where the space charge is present. Inthis work, a simplified space charge drift model...

  8. Computer simulation of ground coupled storage in a series solar assisted heat pump system

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, John W.; Metz, Philip D.

    1979-01-01

    A quantitative study of the effect of thermal coupling between the ground and the heat storage element of a series solar assisted heat pump system is presented. The transient simulation computer program TRNSYS is used to simulate the solar portion of this system. A program to simulate the thermal interaction of the storage element with the ground is incorporated into TRNSYS as a sub-routine. This program calculates heat flow through the ground in discrete steps over space and time. Boundary conditions are established. The ground coupled storage is driven by thermal inputs from the solar portion of the system and from the changing ambient and ground temperatures.

  9. High Frequency Ground Motion from Finite Fault Rupture Simulations

    Science.gov (United States)

    Crempien, Jorge G. F.

    There are many tectonically active regions on earth with little or no recorded ground motions. The Eastern United States is a typical example of regions with active faults, but with low to medium seismicity that has prevented sufficient ground motion recordings. Because of this, it is necessary to use synthetic ground motion methods in order to estimate the earthquake hazard a region might have. Ground motion prediction equations for spectral acceleration typically have geometric attenuation proportional to the inverse of distance away from the fault. Earthquakes simulated with one-dimensional layered earth models have larger geometric attenuation than the observed ground motion recordings. We show that as incident angles of rays increase at welded boundaries between homogeneous flat layers, the transmitted rays decrease in amplitude dramatically. As the receiver distance increases away from the source, the angle of incidence of up-going rays increases, producing negligible transmitted ray amplitude, thus increasing the geometrical attenuation. To work around this problem we propose a model in which we separate wave propagation for low and high frequencies at a crossover frequency, typically 1Hz. The high-frequency portion of strong ground motion is computed with a homogeneous half-space and amplified with the available and more complex one- or three-dimensional crustal models using the quarter wavelength method. We also make use of seismic coda energy density observations as scattering impulse response functions. We incorporate scattering impulse response functions into our Green's functions by convolving the high-frequency homogeneous half-space Green's functions with normalized synthetic scatterograms to reproduce scattering physical effects in recorded seismograms. This method was validated against ground motion for earthquakes recorded in California and Japan, yielding results that capture the duration and spectral response of strong ground motion.

  10. Type-segregated aerosol effects on regional monsoon activity: A study using ground-based experiments and model simulations

    Science.gov (United States)

    Vijayakumar, K.; Devara, P. C. S.; Sonbawne, S. M.

    2014-12-01

    Classification of observed aerosols into key types [e.g., clean-maritime (CM), desert-dust (DD), urban-industrial/biomass-burning (UI/BB), black carbon (BC), organic carbon (OC) and mixed-type aerosols (MA)] would facilitate to infer aerosol sources, effects, and feedback mechanisms, not only to improve the accuracy of satellite retrievals but also to quantify the assessment of aerosol radiative impacts on climate. In this paper, we report the results of a study conducted in this direction, employing a Cimel Sun-sky radiometer at the Indian Institute of Tropical Meteorology (IITM), Pune, India during 2008 and 2009, which represent two successive contrasting monsoon years. The study provided an observational evidence to show that the local sources are subject to heavy loading of absorbing aerosols (dust and black carbon), with strong seasonality closely linked to the monsoon annual rainfall cycle over Pune, a tropical urban station in India. The results revealed the absence of CM aerosols in the pre-monsoon as well as in the monsoon seasons of 2009 as opposed to 2008. Higher loading of dust aerosols is observed in the pre-monsoon and monsoon seasons of 2009; majority may be coated with fine BC aerosols from local emissions, leading to reduction in regional rainfall. Further, significant decrease in coarse-mode AOD and presence of carbonaceous aerosols, affecting the aerosol-cloud interaction and monsoon-rain processes via microphysics and dynamics, is considered responsible for the reduction in rainfall during 2009. Additionally, we discuss how optical depth, contributed by different types of aerosols, influences the distribution of monsoon rainfall over an urban region using the Monitoring Atmospheric Composition and Climate (MACC) aerosol reanalysis. Furthermore, predictions of the Dust REgional Atmospheric Model (DREAM) simulations combined with HYSPLIT (HYbrid Single Particle Lagrangian Integrated Trajectory) cluster model are also discussed in support of the

  11. FDTD simulation of LEMP propagation over lossy ground: Influence of distance, ground conductivity, and source parameters

    Science.gov (United States)

    Aoki, Masanori; Baba, Yoshihiro; Rakov, Vladimir A.

    2015-08-01

    We have computed lightning electromagnetic pulses (LEMPs), including the azimuthal magnetic field Hφ, vertical electric field Ez, and horizontal (radial) electric field Eh that propagated over 5 to 200 km of flat lossy ground, using the finite difference time domain (FDTD) method in the 2-D cylindrical coordinate system. This is the first systematic full-wave study of LEMP propagation effects based on a realistic return-stroke model and including the complete return-stroke frequency range. Influences of the return-stroke wavefront speed (ranging from c/2 to c, where c is the speed of light), current risetime (ranging from 0.5 to 5 µs), and ground conductivity (ranging from 0.1 mS/m to ∞) on Hφ, Ez, and Eh have been investigated. Also, the FDTD-computed waveforms of Eh have been compared with the corresponding ones computed using the Cooray-Rubinstein formula. Peaks of Hφ, Ez, and Eh are nearly proportional to the return-stroke wavefront speed. The peak of Eh decreases with increasing current risetime, while those of Hφ and Ez are only slightly influenced by it. The peaks of Hφ and Ez are essentially independent of the ground conductivity at a distance of 5 km. Beyond this distance, they appreciably decrease relative to the perfectly conducting ground case, and the decrease is stronger for lower ground conductivity values. The peak of Eh increases with decreasing ground conductivity. The computed Eh/Ez is consistent with measurements of Thomson et al. (1988). The observed decrease of Ez peak and increase of Ez risetime due to propagation over 200 km of Florida soil are reasonably well reproduced by the FDTD simulation with ground conductivity of 1 mS/m.

  12. Investigating the effect of bottom boundary condition placement on ground heat storage in climate time scale simulations using ParflowE

    Science.gov (United States)

    Khorsandi, Ehsan; Kollet, Stefan; Venema, Victor; Simmer, Clemens

    2014-05-01

    Heat and water fluxes are key variables affecting the atmosphere-land surface interactions as well as transpiration by plants and geochemical cycles. At climate timescales, the subsurface thermal regime may impact the land surface energy balance via the ground heat flux and associated temperature feedbacks. As a matter of fact, since there is no real lower energy boundary condition, except the natural geothermal heat flux, the subsurface may act as an infinite heat sink in case of a positive temperature trend at the surface. However, due to computational reasons, climate models incorporate a shallow subsurface domain, and thus a shallow temperature boundary condition, which generally is of the Neumann type. This leads to a cumulative ground heat flux of zero over large time scales, which is not realistic, in case of a trend in air temperature. Additionally, the convection term of heat transfer in the subsurface and the memory effect of soil moisture on energy transport is also neglected in climate models by simplified parameterizations. Single soil column model experiments were performed with ParflowE as a subsurface model, which incorporates the more complete heat equation coupled to variably saturated flow, to study the effect of bottom boundary condition placement on ground heat storage and propagated temperature signals over large time-scale with respect to the hydro dynamic process and energy balances. Simulations were carried out over one hundred years (2002-2101) using 4 simple soil columns with the same soil characteristic, lateral boundary conditions and atmosphere forcing, but differing in depth (12, 24, 75 and 150m). After a spin-up period, the models were forced with step-change air temperature and GCM model results namely the IPCC RCP 8.5 scenarios, in order to identify the climate change signals in the subsurface and the associated feedbacks at the land surface. While in the deep soil column, temperature profiles show a heat distribution which is

  13. Wake Vortex Transport and Decay in Ground Effect: Vortex Linking with the Ground

    Science.gov (United States)

    Proctor, Fred H.; Hamilton, David W.; Han, Jongil

    2000-01-01

    Numerical simulations are carried out with a three-dimensional Large-Eddy Simulation (LES) model to explore the sensitivity of vortex decay and transport in ground effect (IGE). The vortex decay rates are found to be strongly enhanced following maximum descent into ground effect. The nondimensional decay rate is found to be insensitive to the initial values of circulation, height, and vortex separation. The information gained from these simulations is used to construct a simple decay relationship. This relationship compares well with observed data from an IGE case study. Similarly, a relationship for lateral drift due to ground effect is constructed from the LES data. In the second part of this paper, vortex linking with the ground is investigated. Our numerical simulations of wake vortices for IGE show that a vortex may link with its image beneath the ground, if the intensity of the ambient turbulence is moderate to high. This linking with the ground (which is observed in real cases)gives the appearance of a vortex tube that bends to become vertically oriented and which terminates at the ground. From the simulations conducted, the linking time for vortices in the free atmosphere; i.e., a function of ambient turbulence intensity.

  14. Engineering uses of physics-based ground motion simulations

    Science.gov (United States)

    Baker, Jack W.; Luco, Nicolas; Abrahamson, Norman A.; Graves, Robert W.; Maechling, Phillip J.; Olsen, Kim B.

    2014-01-01

    This paper summarizes validation methodologies focused on enabling ground motion simulations to be used with confidence in engineering applications such as seismic hazard analysis and dynmaic analysis of structural and geotechnical systems. Numberical simullation of ground motion from large erthquakes, utilizing physics-based models of earthquake rupture and wave propagation, is an area of active research in the earth science community. Refinement and validatoin of these models require collaboration between earthquake scientists and engineering users, and testing/rating methodolgies for simulated ground motions to be used with confidence in engineering applications. This paper provides an introduction to this field and an overview of current research activities being coordinated by the Souther California Earthquake Center (SCEC). These activities are related both to advancing the science and computational infrastructure needed to produce ground motion simulations, as well as to engineering validation procedures. Current research areas and anticipated future achievements are also discussed.

  15. Research for Lunar Dust Effects and Its Ground Simulation Methods%月尘环境效应及地面模拟技术

    Institute of Scientific and Technical Information of China (English)

    童靖宇; 李蔓; 白羽; 田东波

    2013-01-01

    介绍了月球尘的特点及其对探月活动的影响.在分析月球尘环境及其对月面探测器污染、磨损、阻塞、静电效应的基础上,对月球尘环境模拟技术、月球尘扬尘及其运动学和动力学规律、月球尘效应防护及试验评价方法等研究方向和重点提出了一些初步看法.针对研究内容的需求,梳理出一台完整的月球尘地面模拟试验设备应具备真空、温度、太阳风、太阳紫外、月球尘、月面电场、月面磁场等环境因素.在此基础上,设计了一种月球尘地面模拟试验装置方案,并对月球尘环境效应试验方法进行了初步讨论.为月球探测后期任务条件保障建设及相关研究工作提供参考.%The character of lunar dust and its effects on lunar exploration were introduced.Based on analysis of lunar environment and its effects on lunar explorer,such as contamination,abrasion,choke and static,some preliminary propositions for key research topics were given,including lunar dust environment simulation,the causes of lunar dust risen,the kinematics and dynamics characteristic of lunar dust,lunar dust mitigation and test evaluation methods.According to the requirements of these topics,the principal environments for a complete lunar dust simulation facility was generalized,such as vacuum,temperature,solar wind,solar ultraviolet,lunar dust,electric field and magnetic field of lunar surface.Then the project of a new lunar dust ground simulation facility was designed.The test methods for lunar environment effects were discussed preliminarily.The proposed method can give a reference for facility develsopment and test research in future lunar exploration.

  16. A scale model wind tunnel study of dispersion in the Cleveland area. Laboratory simulation of lake breeze effects on diffusion from ground level emissions

    Science.gov (United States)

    Hoydysh, W. G.

    1974-01-01

    A wind tunnel simulation of the diffusion patterns in a sea breeze was attempted. The results indicate that the low level onshore flow was well simulated for neutral, stable, unstable, and elevated inversion conditions. Velocity, turbulence, shear stress, and temperature data were taken, and the spread of emissions from ground level sources was investigated. Comparison is made with theoretical predictions by E. Inoue and with the open, homogeneous plane field results of Pasquill. Agreement with the predictions by Inoue is good, and the comparison with Pasquill's results shows that the wind tunnel flows are shifted two categories towards more stable. The discrepancy may be explained as a matter of averaging time.

  17. Simulation of ground motion using the stochastic method

    Science.gov (United States)

    Boore, D.M.

    2003-01-01

    A simple and powerful method for simulating ground motions is to combine parametric or functional descriptions of the ground motion's amplitude spectrum with a random phase spectrum modified such that the motion is distributed over a duration related to the earthquake magnitude and to the distance from the source. This method of simulating ground motions often goes by the name "the stochastic method." It is particularly useful for simulating the higher-frequency ground motions of most interest to engineers (generally, f>0.1 Hz), and it is widely used to predict ground motions for regions of the world in which recordings of motion from potentially damaging earthquakes are not available. This simple method has been successful in matching a variety of ground-motion measures for earthquakes with seismic moments spanning more than 12 orders of magnitude and in diverse tectonic environments. One of the essential characteristics of the method is that it distills what is known about the various factors affecting ground motions (source, path, and site) into simple functional forms. This provides a means by which the results of the rigorous studies reported in other papers in this volume can be incorporated into practical predictions of ground motion.

  18. Mathematical Simulation of Transient Parameters of Vertical Grounding Electrodes

    Directory of Open Access Journals (Sweden)

    A. Dziaruhina

    2012-01-01

    Full Text Available The paper contains a mathematical simulation of transient parameters of vertical grounding electrodes for the first and subsequent short strokes of a lightning current. Results of the research show that transient resistances of grounding electrodes change appreciably in time. The transient resistances are always higher in the moment of voltage maximum then in the moment of current maximum. The dependences of transient resistances on grounding electrode length at different ground conductivity and lightning current parameters (first and subsequent short strokes are obtained in the paper. The paper proposes an approximate criterion for estimation of grounding electrode equivalent length at transient condition that considers short stroke parameters of the lightning current and ground conductivity.

  19. Ground Contact Model for Mars Science Laboratory Mission Simulations

    Science.gov (United States)

    Raiszadeh, Behzad; Way, David

    2012-01-01

    The Program to Optimize Simulated Trajectories II (POST 2) has been successful in simulating the flight of launch vehicles and entry bodies on earth and other planets. POST 2 has been the primary simulation tool for the Entry Descent, and Landing (EDL) phase of numerous Mars lander missions such as Mars Pathfinder in 1997, the twin Mars Exploration Rovers (MER-A and MER-B) in 2004, Mars Phoenix lander in 2007, and it is now the main trajectory simulation tool for Mars Science Laboratory (MSL) in 2012. In all previous missions, the POST 2 simulation ended before ground impact, and a tool other than POST 2 simulated landing dynamics. It would be ideal for one tool to simulate the entire EDL sequence, thus avoiding errors that could be introduced by handing off position, velocity, or other fight parameters from one simulation to the other. The desire to have one continuous end-to-end simulation was the motivation for developing the ground interaction model in POST 2. Rover landing, including the detection of the postlanding state, is a very critical part of the MSL mission, as the EDL landing sequence continues for a few seconds after landing. The method explained in this paper illustrates how a simple ground force interaction model has been added to POST 2, which allows simulation of the entire EDL from atmospheric entry through touchdown.

  20. Simulation of non-stationary ground motion processes (II)

    Institute of Scientific and Technical Information of China (English)

    LIANG Jian-wen

    2005-01-01

    This paper proposes a method for simulation of non-stationary ground motion processes having the identical statistical feature, time-dependent power spectrum, with a given ground motion record, on the basis of review of simulation of non-stationary ground motion processes. The method has the following advantages: the sample processes are non-stationary both in amplitude and frequency, and both the amplitude and frequency non-stationarity depend on the target power spectrum; the power spectrum of any sample process does not necessarily accord with the target power spectrum, but statistically, it strictly accords with the target power spectrum. Finally, the method is verified by simulation of one acceleration record in Landers earthquake.

  1. A Ground Control Station for the UAV Flight Simulator

    Directory of Open Access Journals (Sweden)

    Romaniuk Sławomir

    2016-03-01

    Full Text Available In the paper implementation of a ground control station for UAV flight simulator is shown. The ground control station software is in cooperation with flight simulator, displaying various aircraft flight parameters. The software is programmed in C++ language and utilizes the windows forms for implementing graphical content. One of the main aims of the design of the application was to simplify the interface, simultaneously maintaining the functionality and the eligibility. A mission can be planned and monitored using the implemented map control supported by waypoint list.

  2. Ground motion modeling of Hayward fault scenario earthquakes II:Simulation of long-period and broadband ground motions

    Energy Technology Data Exchange (ETDEWEB)

    Aagaard, B T; Graves, R W; Rodgers, A; Brocher, T M; Simpson, R W; Dreger, D; Petersson, N A; Larsen, S C; Ma, S; Jachens, R C

    2009-11-04

    We simulate long-period (T > 1.0-2.0 s) and broadband (T > 0.1 s) ground motions for 39 scenarios earthquakes (Mw 6.7-7.2) involving the Hayward, Calaveras, and Rodgers Creek faults. For rupture on the Hayward fault we consider the effects of creep on coseismic slip using two different approaches, both of which reduce the ground motions compared with neglecting the influence of creep. Nevertheless, the scenario earthquakes generate strong shaking throughout the San Francisco Bay area with about 50% of the urban area experiencing MMI VII or greater for the magnitude 7.0 scenario events. Long-period simulations of the 2007 Mw 4.18 Oakland and 2007 Mw 4.5 Alum Rock earthquakes show that the USGS Bay Area Velocity Model version 08.3.0 permits simulation of the amplitude and duration of shaking throughout the San Francisco Bay area, with the greatest accuracy in the Santa Clara Valley (San Jose area). The ground motions exhibit a strong sensitivity to the rupture length (or magnitude), hypocenter (or rupture directivity), and slip distribution. The ground motions display a much weaker sensitivity to the rise time and rupture speed. Peak velocities, peak accelerations, and spectral accelerations from the synthetic broadband ground motions are, on average, slightly higher than the Next Generation Attenuation (NGA) ground-motion prediction equations. We attribute at least some of this difference to the relatively narrow width of the Hayward fault ruptures. The simulations suggest that the Spudich and Chiou (2008) directivity corrections to the NGA relations could be improved by including a dependence on the rupture speed and increasing the areal extent of rupture directivity with period. The simulations also indicate that the NGA relations may under-predict amplification in shallow sedimentary basins.

  3. Hybrid Broadband Ground-Motion Simulation Using Scenario Earthquakes for the Istanbul Area

    KAUST Repository

    Reshi, Owais A.

    2016-04-13

    Seismic design, analysis and retrofitting of structures demand an intensive assessment of potential ground motions in seismically active regions. Peak ground motions and frequency content of seismic excitations effectively influence the behavior of structures. In regions of sparse ground motion records, ground-motion simulations provide the synthetic seismic records, which not only provide insight into the mechanisms of earthquakes but also help in improving some aspects of earthquake engineering. Broadband ground-motion simulation methods typically utilize physics-based modeling of source and path effects at low frequencies coupled with high frequency semi-stochastic methods. I apply the hybrid simulation method by Mai et al. (2010) to model several scenario earthquakes in the Marmara Sea, an area of high seismic hazard. Simulated ground motions were generated at 75 stations using systematically calibrated model parameters. The region-specific source, path and site model parameters were calibrated by simulating a w4.1 Marmara Sea earthquake that occurred on November 16, 2015 on the fault segment in the vicinity of Istanbul. The calibrated parameters were then used to simulate the scenario earthquakes with magnitudes w6.0, w6.25, w6.5 and w6.75 over the Marmara Sea fault. Effects of fault geometry, hypocenter location, slip distribution and rupture propagation were thoroughly studied to understand variability in ground motions. A rigorous analysis of waveforms reveal that these parameters are critical for determining the behavior of ground motions especially in the near-field. Comparison of simulated ground motion intensities with ground-motion prediction quations indicates the need of development of the region-specific ground-motion prediction equation for Istanbul area. Peak ground motion maps are presented to illustrate the shaking in the Istanbul area due to the scenario earthquakes. The southern part of Istanbul including Princes Islands show high amplitudes

  4. Ground-motion modeling of Hayward fault scenario earthquakes, part II: Simulation of long-period and broadband ground motions

    Science.gov (United States)

    Aagaard, Brad T.; Graves, Robert W.; Rodgers, Arthur; Brocher, Thomas M.; Simpson, Robert W.; Dreger, Douglas; Petersson, N. Anders; Larsen, Shawn C.; Ma, Shuo; Jachens, Robert C.

    2010-01-01

    We simulate long-period (T>1.0–2.0 s) and broadband (T>0.1 s) ground motions for 39 scenario earthquakes (Mw 6.7–7.2) involving the Hayward, Calaveras, and Rodgers Creek faults. For rupture on the Hayward fault, we consider the effects of creep on coseismic slip using two different approaches, both of which reduce the ground motions, compared with neglecting the influence of creep. Nevertheless, the scenario earthquakes generate strong shaking throughout the San Francisco Bay area, with about 50% of the urban area experiencing modified Mercalli intensity VII or greater for the magnitude 7.0 scenario events. Long-period simulations of the 2007 Mw 4.18 Oakland earthquake and the 2007 Mw 5.45 Alum Rock earthquake show that the U.S. Geological Survey’s Bay Area Velocity Model version 08.3.0 permits simulation of the amplitude and duration of shaking throughout the San Francisco Bay area for Hayward fault earthquakes, with the greatest accuracy in the Santa Clara Valley (San Jose area). The ground motions for the suite of scenarios exhibit a strong sensitivity to the rupture length (or magnitude), hypocenter (or rupture directivity), and slip distribution. The ground motions display a much weaker sensitivity to the rise time and rupture speed. Peak velocities, peak accelerations, and spectral accelerations from the synthetic broadband ground motions are, on average, slightly higher than the Next Generation Attenuation (NGA) ground-motion prediction equations. We attribute much of this difference to the seismic velocity structure in the San Francisco Bay area and how the NGA models account for basin amplification; the NGA relations may underpredict amplification in shallow sedimentary basins. The simulations also suggest that the Spudich and Chiou (2008) directivity corrections to the NGA relations could be improved by increasing the areal extent of rupture directivity with period.

  5. Numerical Study of Wake Vortex Interaction with the Ground Using the Terminal Area Simulation System

    Science.gov (United States)

    Proctor, Fred H.; Han, Jongil

    1999-01-01

    A sensitivity study for the in-ground effect on aircraft wake vortices has been conducted using a validated large eddy simulation model. The numerical results are compared with observed data and show good agreement for vortex decay and lateral vortex transport. The vortex decay rate is strongly influenced by the ground, but appears somewhat insensitive to ambient turbulence. In addition, the results show that the ground can affect the trajectory and descent-rate of a wake vortex pair at elevations up to about 3 b(sub o) (where b(sub o) is the initial vortex separation). However, the ground does not influence the average circulation of the vortices until the cores descend to within about 0.6 b(sub o), after which time the ground greatly enhances their rate of demise. Vortex rebound occurs in the simulations, but is more subtle than shown in previous numerical studies.

  6. Simulation of regional ground-water flow in the Upper Deschutes Basin, Oregon

    Science.gov (United States)

    Gannett, Marshall W.; Lite, Kenneth E.

    2004-01-01

    streams is also well simulated throughout the model. Ground-water discharge to streams in the area of the confluence of the Deschutes, Crooked, and Metolius Rivers is closely matched. The model was also calibrated to transient conditions from 1978 to 1997 using traditional trial-and-error methods. Climatic cycles during this period provided an excellent regional hydrologic signal for calibration. Climate-driven water-level fluctuations are simulated with reasonable accuracy over most of the model area. The timing and magnitude of simulated water-level fluctuations caused by annual pulses of recharge from precipitation match those observed reasonably well, given the limitations of the time discretization in the model. Water-level fluctuations caused by annual canal leakage are simulated very well over most of the area where such fluctuations occur. The transient model also simulates the volumetric distribution and temporal variations in ground-water discharge reasonably well. The match between simulated and measured volume of and variations in ground-water discharge is, however, somewhat dependent on geographic scale. The rates of and variations in ground-water discharge are matched best at regional scales. Example simulations were made to demonstrate the utility of the model for evaluating the effects of ground-water pumping or canal lining. Pumping simulations show that pumped water comes largely from aquifer storage when pumping begins, but as the water table stabilizes, the pumping increasingly diminishes the discharge to streams and, hence, streamflow. The time it takes for pumping to affect streamflow varies spatially depending, in general, on the location of pumping relative to the discharge areas. Canal-lining simulations show similar effects.

  7. Analysis of ground-motion simulation big data

    Science.gov (United States)

    Maeda, T.; Fujiwara, H.

    2016-12-01

    We developed a parallel distributed processing system which applies a big data analysis to the large-scale ground motion simulation data. The system uses ground-motion index values and earthquake scenario parameters as input. We used peak ground velocity value and velocity response spectra as the ground-motion index. The ground-motion index values are calculated from our simulation data. We used simulated long-period ground motion waveforms at about 80,000 meshes calculated by a three dimensional finite difference method based on 369 earthquake scenarios of a great earthquake in the Nankai Trough. These scenarios were constructed by considering the uncertainty of source model parameters such as source area, rupture starting point, asperity location, rupture velocity, fmax and slip function. We used these parameters as the earthquake scenario parameter. The system firstly carries out the clustering of the earthquake scenario in each mesh by the k-means method. The number of clusters is determined in advance using a hierarchical clustering by the Ward's method. The scenario clustering results are converted to the 1-D feature vector. The dimension of the feature vector is the number of scenario combination. If two scenarios belong to the same cluster the component of the feature vector is 1, and otherwise the component is 0. The feature vector shows a `response' of mesh to the assumed earthquake scenario group. Next, the system performs the clustering of the mesh by k-means method using the feature vector of each mesh previously obtained. Here the number of clusters is arbitrarily given. The clustering of scenarios and meshes are performed by parallel distributed processing with Hadoop and Spark, respectively. In this study, we divided the meshes into 20 clusters. The meshes in each cluster are geometrically concentrated. Thus this system can extract regions, in which the meshes have similar `response', as clusters. For each cluster, it is possible to determine

  8. Investigation of topographical effects on rupture dynamics and ground motions

    Science.gov (United States)

    Huang, H.; Chen, X.; Zhang, Z.

    2016-12-01

    Using the curved grid finite-difference method (CG-FDM), we model spontaneous dynamic rupture on vertical strike-slip faults with irregular free surfaces to investigate the effect of topography on near-source ground motion. Four groups of simulations, in which the epicentral distances from the topographical perturbations of the nucleation patch were varied, are modeled in this work. The simulated results show that the presence of irregular topography along the fault trace may increase the ground motion. Whether the irregular topography exhibits higher ground motion overall depends on the irregular topography's ability to prevent the sub-Rayleigh-to-supershear transition. When irregular topography prevents this transition, sub-Rayleigh rupture produces stronger ground motions than those of the sub-Rayleigh-to-supershear transition, although the moment magnitudes does not differ substantially between the two cases. To thoroughly understand the effects of irregular topography on near-source ground motion, we also model spontaneous dynamic rupture on a planar fault in full-space and half-space with varying initial shear stresses, and the corresponding modeling results indicate that the effect of initial shear stress on near-source ground motion is strong. These results may have implications for ground-motion prediction in future earthquakes involving geometrically complex faults.

  9. Hourly simulation of a Ground-Coupled Heat Pump system

    Science.gov (United States)

    Naldi, C.; Zanchini, E.

    2017-01-01

    In this paper, we present a MATLAB code for the hourly simulation of a whole Ground-Coupled Heat Pump (GCHP) system, based on the g-functions previously obtained by Zanchini and Lazzari. The code applies both to on-off heat pumps and to inverter-driven ones. It is employed to analyse the effects of the inverter and of the total length of the Borehole Heat Exchanger (BHE) field on the mean seasonal COP (SCOP) and on the mean seasonal EER (SEER) of a GCHP system designed for a residential house with 6 apartments in Bologna, North-Center Italy, with dominant heating loads. A BHE field with 3 in line boreholes is considered, with length of each BHE either 75 m or 105 m. The results show that the increase of the BHE length yields a SCOP enhancement of about 7%, while the SEER remains nearly unchanged. The replacement of the on-off heat pump by an inverter-driven one yields a SCOP enhancement of about 30% and a SEER enhancement of about 50%. The results demonstrate the importance of employing inverter-driven heat pumps for GCHP systems.

  10. Broad-band near-field ground motion simulations in 3-dimensional scattering media

    Science.gov (United States)

    Imperatori, W.; Mai, P. M.

    2013-02-01

    The heterogeneous nature of Earth's crust is manifested in the scattering of propagating seismic waves. In recent years, different techniques have been developed to include such phenomenon in broad-band ground-motion calculations, either considering scattering as a semi-stochastic or purely stochastic process. In this study, we simulate broad-band (0-10 Hz) ground motions with a 3-D finite-difference wave propagation solver using several 3-D media characterized by von Karman correlation functions with different correlation lengths and standard deviation values. Our goal is to investigate scattering characteristics and its influence on the seismic wavefield at short and intermediate distances from the source in terms of ground motion parameters. We also examine scattering phenomena, related to the loss of radiation pattern and the directivity breakdown. We first simulate broad-band ground motions for a point-source characterized by a classic ω2 spectrum model. Fault finiteness is then introduced by means of a Haskell-type source model presenting both subshear and super-shear rupture speed. Results indicate that scattering plays an important role in ground motion even at short distances from the source, where source effects are thought to be dominating. In particular, peak ground motion parameters can be affected even at relatively low frequencies, implying that earthquake ground-motion simulations should include scattering also for peak ground velocity (PGV) calculations. At the same time, we find a gradual loss of the source signature in the 2-5 Hz frequency range, together with a distortion of the Mach cones in case of super-shear rupture. For more complex source models and truly heterogeneous Earth, these effects may occur even at lower frequencies. Our simulations suggests that von Karman correlation functions with correlation length between several hundred metres and few kilometres, Hurst exponent around 0.3 and standard deviation in the 5-10 per cent range

  11. Broad-band near-field ground motion simulations in 3-dimensional scattering media

    KAUST Repository

    Imperatori, W.

    2012-12-06

    The heterogeneous nature of Earth\\'s crust is manifested in the scattering of propagating seismic waves. In recent years, different techniques have been developed to include such phenomenon in broad-band ground-motion calculations, either considering scattering as a semi-stochastic or purely stochastic process. In this study, we simulate broad-band (0–10 Hz) ground motions with a 3-D finite-difference wave propagation solver using several 3-D media characterized by von Karman correlation functions with different correlation lengths and standard deviation values. Our goal is to investigate scattering characteristics and its influence on the seismic wavefield at short and intermediate distances from the source in terms of ground motion parameters. We also examine scattering phenomena, related to the loss of radiation pattern and the directivity breakdown. We first simulate broad-band ground motions for a point-source characterized by a classic ω2 spectrum model. Fault finiteness is then introduced by means of a Haskell-type source model presenting both subshear and super-shear rupture speed. Results indicate that scattering plays an important role in ground motion even at short distances from the source, where source effects are thought to be dominating. In particular, peak ground motion parameters can be affected even at relatively low frequencies, implying that earthquake ground-motion simulations should include scattering also for peak ground velocity (PGV) calculations. At the same time, we find a gradual loss of the source signature in the 2–5 Hz frequency range, together with a distortion of the Mach cones in case of super-shear rupture. For more complex source models and truly heterogeneous Earth, these effects may occur even at lower frequencies. Our simulations suggests that von Karman correlation functions with correlation length between several hundred metres and few kilometres, Hurst exponent around 0.3 and standard deviation in the 5–10 per cent

  12. Overview of Ground-Motion Issues for Cascadia Megathrust Events: Simulation of Ground-Motions and Earthquake Site Response

    Directory of Open Access Journals (Sweden)

    Hadi Ghofrani

    2017-09-01

    Full Text Available Ground motions for earthquakes of M7.5 to 9.0 on the Cascadia subduction interface are simulated based on a stochastic finite-fault model and used to estimate average response spectra for reference firm soil conditions. The simulations are first validated by modeling the wealth of ground-motion data from the 2011 M9.0 Tohoku earthquake of Japan. Adjustments to the calibrated model are then made to consider average source, attenuation and site parameters for the Cascadia region. This includes an evaluation of the likely variability in stress drop for large interface earthquakes and an assessment of regional attenuation and site effects. We perform best-estimate simulations for a preferred set of input parameters. Typical results suggest mean values of 5%-damped pseudoacceleration in the range from about 100 to 200 cm/s2, at frequencies from 1 to 4 Hz, for firm-ground conditions in Vancouver. Uncertainty in most-likely value of the parameter representing stress drop causes variability in simulated response spectra of about ±50%. Uncertainties in the attenuation model produce even larger variability in response spectral amplitudes—a factor of about two at a closest distance to the rupture plane (Rcd of 100 km, becoming even larger at greater distances. It is thus important to establish the regional attenuation model for ground-motion simulations and to bound the source properties controlling radiation of ground motion. We calculate theoretical one-dimensional spectral amplification estimates for four selected Fraser River Delta sites to show how the presence of softer sediments in the region may alter the predicted ground motions. The amplification functions are largely consistent with observed spectral amplification at Fraser River delta sites, suggesting amplification by factors of 2.5–5 at the peak frequency of the site; we note that deep sites in the delta have a low peak frequency, ∼0.3 Hz. This work will aid in seismic hazard

  13. Numerical simulation and experimental validation of aircraft ground deicing model

    Directory of Open Access Journals (Sweden)

    Bin Chen

    2016-05-01

    Full Text Available Aircraft ground deicing plays an important role of guaranteeing the aircraft safety. In practice, most airports generally use as many deicing fluids as possible to remove the ice, which causes the waste of the deicing fluids and the pollution of the environment. Therefore, the model of aircraft ground deicing should be built to establish the foundation for the subsequent research, such as the optimization of the deicing fluid consumption. In this article, the heat balance of the deicing process is depicted, and the dynamic model of the deicing process is provided based on the analysis of the deicing mechanism. In the dynamic model, the surface temperature of the deicing fluids and the ice thickness are regarded as the state parameters, while the fluid flow rate, the initial temperature, and the injection time of the deicing fluids are treated as control parameters. Ignoring the heat exchange between the deicing fluids and the environment, the simplified model is obtained. The rationality of the simplified model is verified by the numerical simulation and the impacts of the flow rate, the initial temperature and the injection time on the deicing process are investigated. To verify the model, the semi-physical experiment system is established, consisting of the low-constant temperature test chamber, the ice simulation system, the deicing fluid heating and spraying system, the simulated wing, the test sensors, and the computer measure and control system. The actual test data verify the validity of the dynamic model and the accuracy of the simulation analysis.

  14. Simulated effects of projected withdrawals from the Wenonah-Mount Laurel Aquifer on ground-water levels in the Camden, New Jersey, area and vicinity

    Science.gov (United States)

    Navoy, A.S.

    1994-01-01

    The Wenonah-Mount Laurel aquifer is being considered as a potential source of future water supply for the Camden, New Jersey, area. The deeper Potomac- Raritan-Magothy aquifer system is currently the major major source of water supply for the area, but its use may be curtailed or reduced by 35 percent of 1983 withdrawals through its designation by the New Jersey Department of Environmental Protection and Energy as "Water Supply Critical Area#2." Withdrawals from the Wenonah-Mount Laurel aquifer currently (1989) total about 7 million gallons per day. The anticipated use of this aquifer by communities with access to it, as an alternative supply, could increase to more than 14 million gallons per day by 2020. If the communities of Clayton and Glassboro decrease their withdrawals from the Potomac-Raritan-Magothy aquifer system by 50 percent or cease them entirely because of their proximity to saline water, the use of Wenonah-Mount Laurel aquifer could increase to greater than 15 million gallons per day by 2020. Simulation of the ground-water system indicates that the projected increase in withdrawals will cause cones of depression in the potentiometric surface of the Wenonah-Mount Laurel aquifer in the Camden metro- politan area by 2020 that extend to depths ranging from 10 feet above sea level to 60 feet below sea level. This represents a secline of about 40 to 100 feet thr 1990 conditions. Withdrawals in northeastern Burlington County will cause a large cone of depression that, by 2020, will extend to depths of about 220 feet below sea level, represent- ing a decline of about 140 feet from 1990 conditions. Simulation results indicate that water levels in the Wenonah-Mount Laurel aquifer near the Salem Nuclear Power Plant are somewhat insensitive to withdrawals elsewhere in the aquifer. In some areas, especially in Burlington County, the cones of depression have developed in proximity to the aquifer-outcrop area and could induce infiltration from streams crossing the

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

    Science.gov (United States)

    Juckem, Paul F.

    2009-01-01

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

  16. Simulation of the hydrogen ground state in stochastic electrodynamics

    Science.gov (United States)

    Nieuwenhuizen, Theo M.; Liska, Matthew T. P.

    2015-10-01

    Stochastic electrodynamics is a classical theory which assumes that the physical vacuum consists of classical stochastic fields with average energy \\frac{1}{2}{{\\hslash }}ω in each mode, i.e., the zero-point Planck spectrum. While this classical theory explains many quantum phenomena related to harmonic oscillator problems, hard results on nonlinear systems are still lacking. In this work the hydrogen ground state is studied by numerically solving the Abraham-Lorentz equation in the dipole approximation. First the stochastic Gaussian field is represented by a sum over Gaussian frequency components, next the dynamics is solved numerically using OpenCL. The approach improves on work by Cole and Zou 2003 by treating the full 3d problem and reaching longer simulation times. The results are compared with a conjecture for the ground state phase space density. Though short time results suggest a trend towards confirmation, in all attempted modellings the atom ionises at longer times.

  17. Ground-water flow and the possible effects of remedial actions at J-Field, Aberdeen Proving Ground, Maryland

    Science.gov (United States)

    Hughes, W.B.

    1995-01-01

    J-Field, located in the Edgewood Area of Aberdeen Proving Ground, Md, has been used since World War II to test and dispose of explosives, chemical warfare agents, and industrial chemicals resulting in ground-water, surface-water, and soil contami- nation. The U.S. Geological Survey finite-difference model was used to better understand ground-water flow at the site and to simulate the effects of remedial actions. A surficial aquifer and a confined aquifer were simulated with the model. A confining unit separates these units and is represented by leakance between the layers. The area modeled is 3.65 mi2; the model was constructed with a variably spaced 40 X 38 grid. The horizontal and lower boundaries of the model are all no-flow boundaries. Steady-state conditions were used. Ground water at the areas under investigation flows from disposal pit areas toward discharge areas in adjacent estuaries or wetlands. Simulations indicate that capping disposal areas with an impermeable cover effectively slows advective ground water flow by 0.7 to 0.5 times. Barriers to lateral ground-water flow were simulated and effectively prevented the movement of ground water toward discharge areas. Extraction wells were simulated as a way to contain ground-water contamination and to extract ground water for treatment. Two wells pumping 5 gallons per minute each at the toxic-materials disposal area and a single well pumping 2.5 gallons per minute at the riot-control-agent disposal area effectively contained contamination at these sites. A combi- nation of barriers to horizontal flow east and south of the toxic-materials disposal area, and a single extraction well pumping at 5 gallons per minute can extract contaminated ground water and prevent pumpage of marsh water.

  18. (AJST) EFFECTS OF GROUND INSULATION AND GREENHOUSE ...

    African Journals Online (AJOL)

    NORBERT OPIYO AKECH

    of plastic digester to produce biogas under natural and greenhouse microenvironment. The specific ... and hydrogen sulphide (H2S). Biogas ... the effect of ground insulation on biogas production. ..... Methane Generation from Human, Animal.

  19. No consistent effect of plant species richness on resistance to simulated climate change for above- or below-ground processes in managed grasslands.

    Science.gov (United States)

    Dormann, Carsten F; von Riedmatten, Lars; Scherer-Lorenzen, Michael

    2017-06-17

    Species richness affects processes and functions in many ecosystems. Since management of temperate grasslands is directly affecting species composition and richness, it can indirectly govern how systems respond to fluctuations in environmental conditions. Our aim in this study was to investigate whether species richness in managed grasslands can buffer the effects of drought and warming manipulations and hence increase the resistance to climate change. We established 45 plots in three regions across Germany, each with three different management regimes (pasture, meadow and mown pasture). We manipulated spring warming using open-top chambers and summer drought using rain-out shelters for 4 weeks. Measurements of species richness, above- and below-ground biomass and soil carbon and nitrogen concentrations showed significant but inconsistent differences among regions, managements and manipulations. We detected a three-way interaction between species richness, management and region, indicating that our study design was sensitive enough to detect even intricate effects. We could not detect a pervasive effect of species richness on biomass differences between treatments and controls, indicating that a combination of spring warming and summer drought effects on grassland systems are not consistently moderated by species richness. We attribute this to the relatively high number of species even at low richness levels, which already provides the complementarity required for positive biodiversity-ecosystem functioning relationships. A review of the literature also indicates that climate manipulations largely fail to show richness-buffering, while natural experiments do, suggesting that such manipulations are milder than reality or incur treatment artefacts.

  20. Simulation of non-stationary ground motion processes (I)

    Institute of Scientific and Technical Information of China (English)

    LIANG Jian-wen

    2005-01-01

    This paper presents a spectral representation method for simulation of non-stationary ground motion processes on the basis of Priestley's evolutionary spectral theory. Following this method, sample processes can be generated using a cosine series formula. It is shown that, these sample processes accurately reflect the prescribed characteristics of the evolutionary power spectral density function when the number of the terms in the cosine series is large enough; and the ensemble expected value and the ensemble autocorrelation function approach the corresponding target functions, respectively, as the sample size increases; and these sample processes are asymptotically normal as the number of the terms in the series tends to infinity. Finally, a few special cases of the formula are discussed, one of which is non-stationary white noise process, and other one is reduced to the formula for simulation of stationary stochastic processes.

  1. Computational Simulation of Dynamic Response of Vehicle Tatra T815 and the Ground

    Science.gov (United States)

    Vlček, Jozef; Valašková, Veronika

    2016-10-01

    The effect of a moving load represents the actual problem which is analysed in engineering practice. The response of the vehicle and its dynamic effect on the pavement can be analysed by experimental or computational ways. The aim of this paper was to perform computer simulations of a vehicle-ground interaction. For this purpose, a half-part model of heavy lorry Tatra 815 and ground was modelled in computational programmes ADINA and PLAXIS based on FEM methods, utilizing analytical approaches. Two procedures were then selected for further calculations. The first one is based on the simplification of the stiffer pavement layers to the beam element supported by the springs simulating the subgrade layers using Winkler-Pasternak theory of elastic half-space. Modulus of subgrade reaction was determined in the standard programme trough the simulation of a plate load test. Second approach considers a multi-layered ground system with layers of different thicknesses and material properties. For comparison of outputs of both approaches, the same input values were used for every calculation procedure. Crucial parameter for the simulations was the velocity of the passing vehicle with regard to the ground response to the impulse of the pass. Lower velocities result in almost static response of the pavement, but higher velocities induce response that can be better described by the dynamic theory. For small deformations, an elastic material model seems to be sufficient to define the ground response to the moving load, but for larger deformations advanced material models for the ground environment would be more reliable.

  2. Broadband Ground Motion Simulations for the Puente Hills Fault System

    Science.gov (United States)

    Graves, R. W.

    2005-12-01

    Recent geologic studies have identified the seismic potential of the Puente Hills fault system. This system is comprised of multiple blind thrust segments, a portion of which ruptured in the Mw 5.9 Whittier-Narrows earthquake. Rupture of the entire system could generate a Mw 7.2 (or larger) earthquake. To assess the potential hazard posed by the fault system, we have simulated the response for several earthquake scenarios. These simulations are unprecedented in scope and scale. Broadband (0-10 Hz) ground motions are computed at 66,000 sites, covering most of the LA metropolitan region. Low frequency (f 1 Hz) motions are calculated using a stochastic approach. We consider scenarios ranging from Mw 6.7 to Mw 7.2, including both high and low stress drop events. Finite-fault rupture models for these scenarios are generated following a wavenumber filtering technique (K-2 model) that has been calibrated against recent earthquakes. In all scenarios, strong rupture directivity channels large amplitude pulses of motion directly into the Los Angeles basin, which then propagate southward as basin surface waves. Typically, the waveforms near downtown Los Angeles are dominated by a strong, concentrated pulse of motion. At Long Beach (across the LA basin from the rupture) the waveforms are dominated by late arriving longer period surface waves. The great density of sites used in the calculation allows the construction of detailed maps of various ground motion parameters (PGA, PGV, SA), as well as full animations of the propagating broadband wave field. Additionally, the broadband time histories are available for use in non-linear response analyses of built structures.

  3. Simulation of the ground-water-flow system in the Kalamazoo County area, Michigan

    Science.gov (United States)

    Luukkonen, Carol L.; Blumer, Stephen P.; Weaver, T.L.; Jean, Julie

    2004-01-01

    A ground-water-flow model was developed to investigate the ground-water resources of Kalamazoo County. Ground water is widely used as a source of water for drinking and industry in Kalamazoo County and the surrounding area. Additionally, lakes and streams are valued for their recreational and aesthetic uses. Stresses on the ground-water system, both natural and human-induced, have raised concerns about the long-term availability of ground water for people to use and for replenishment of lakes and streams. Potential changes in these stresses, including withdrawals and recharge, were simulated using a ground-water-flow model. Simulations included steady-state conditions (in which stresses remained constant and changes in storage were not included) and transient conditions (in which stresses changed in seasonal and monthly time scales and storage within the system was included). Steady-state simulations were used to investigate the long-term effects on water levels and streamflow of a reduction in recharge or an increase in pumping to projected 2010 withdrawal rates, withdrawal and application of water for irrigation, and a reduction in recharge in urban areas caused by impervious surfaces. Transient simulations were used to investigate changes in withdrawals to match seasonal and monthly patterns under various recharge conditions, and the potential effects of the use of water for irrigation over the summer months. With a reduction in recharge, simulated water levels declined over most of the model area in Kalamazoo County; with an increase in pumping, water levels declined primarily near pumping centers. Because withdrawals by wells intercept water that would have discharged possibly to a stream or lake, model simulations indicated that streamflow was reduced with increased withdrawals. With withdrawal and consumption of water for irrigation, simulated water levels declined. Assuming a reduction in recharge due to urbanization, water levels declined and flow to

  4. Numerical Simulation of Heat Transfer Characteristics of Horizontal Ground Heat Exchanger in Frozen Soil Layer

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A simplified numerical model of heat transfer characteristics of horizontal ground heat exchanger (GHE) in the frozen soil layer is presented and the steady-state distribution of temperature field is simulated. Numerical results show that the frozen depth mainly depends on the soil's moisture content and ambient temperature. The heat transfer loss of horizontal GHE tends to grow with the increase of the soil's moisture content and the decrease of ambient temperature. Backfilled materials with optimal thermal conductivity can reduce the thermal loss effectively in the frozen soil. The applicability of the Chinese national standard "Technical Code for Ground Source Heat Pump (GB 50366-2005)" is verified. For a ground source heat pump project, the feasible layout of horizontal GHE should be determined based on the integration of the soil's structure, backfilled materials,weather data, and economic analysis.

  5. Precision simulation of ground-based lensing data using observations from space

    CERN Document Server

    Mandelbaum, Rachel; Leauthaud, Alexie; Massey, Richard J; Rhodes, Jason

    2011-01-01

    Current and upcoming wide-field, ground-based, broad-band imaging surveys promise to address a wide range of outstanding problems in galaxy formation and cosmology. Several such uses of ground-based data, especially weak gravitational lensing, require highly precise measurements of galaxy image statistics with careful correction for the effects of the point-spread function (PSF). In this paper, we introduce the SHERA (SHEar Reconvolution Analysis) software to simulate ground-based imaging data with realistic galaxy morphologies and observing conditions, starting from space-based data (from COSMOS, the Cosmological Evolution Survey) and accounting for the effects of the space-based PSF. This code simulates ground-based data, optionally with a weak lensing shear applied, in a model-independent way using a general Fourier space formalism. The utility of this pipeline is that it allows for a precise, realistic assessment of systematic errors due to the method of data processing, for example in extracting weak len...

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

    Science.gov (United States)

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

    2009-12-01

    nonlinear site response, we conducted FDM simulations of nonlinear seismic wavefield using finite strain formulation and Murnaghan constants that describe the nonlinear properties of surface soil. The nonlinear FDM simulation of ground motion is based on the work of Xu et al. (2000). Our present simulation model is in 2D, but it can be extended to 3D very easy. The Murnaghan constants for this simulation can be determined from a relationship between these constants and S-H/V deformation, which is derived from comparison of the observed S-H/V and that from FDM simulation with different values of these constants. The results of this simulation indicated a dramatic change occurring in the frequency-dependent amplification properties as the strain level near the surface increases. The predominant peak in the Fourier spectra of the S-wave gradually moved to the lower frequency band as the strain level increased from 10^-8 to 10^-6, and high frequency components showed a significant drop. These results correspond well with the observed data mentioned above. This demonstrates the effectiveness of nonlinear FDM simulation for an estimation of actual ground motion and frequency contents in an expected large earthquake.

  7. Grounding Effect on Common Mode Interference of Underground Inverter

    Directory of Open Access Journals (Sweden)

    CHENG Qiang

    2013-09-01

    Full Text Available For the neutral point not grounded characteristics of underground power supply system in coal mine, this paper studied common mode equivalent circuit of underground PWM inverter, and extracted parasitic parameters of interference propagation path. The author established a common mode and differential mode model of underground inverter. Taking into account the rise time of PWM, the simulation results of conducted interference by Matlab software is compared with measurement spectrum on the AC side and motor side of converter, the difference is consistent showing that the proposed method has some validity. After Comparison of calculation results by Matlab simulation ,it can be concluded that ungrounded neutral of transformer could redue common mode current in PWM system, but not very effective, the most efficient way is to increase grounding  impedance of  inverter and motor.

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

    Directory of Open Access Journals (Sweden)

    Pedro Sanchez-Cuevas

    2017-01-01

    Full Text Available This paper analyzes the ground effect in multirotors, that is, the change in the thrust generated by the rotors when flying close to the ground due to the interaction of the rotor airflow with the ground surface. This effect is well known in single-rotor helicopters but has been assumed erroneously to be similar for multirotors in many cases in the literature. In this paper, the ground effect for multirotors is characterized with experimental tests in several cases and the partial ground effect, a situation in which one or some of the rotors of the multirotor (but not all are under the ground effect, is also characterized. The influence of the different cases of ground effect in multirotor control is then studied with several control approaches in simulation and validated with experiments in a test bench and with outdoor flights.

  9. Characterization of Vacuum Facility Background Gas Through Simulation and Considerations for Electric Propulsion Ground Testing

    Science.gov (United States)

    Yim, John T.; Burt, Jonathan M.

    2015-01-01

    The background gas in a vacuum facility for electric propulsion ground testing is examined in detail through a series of cold flow simulations using a direct simulation Monte Carlo (DSMC) code. The focus here is on the background gas itself, its structure and characteristics, rather than assessing its interaction and impact on thruster operation. The background gas, which is often incorrectly characterized as uniform, is found to have a notable velocity within a test facility. The gas velocity has an impact on the proper measurement of pressure and the calculation of ingestion flux to a thruster. There are also considerations for best practices for tests that involve the introduction of supplemental gas flows to artificially increase the background pressure. All of these effects need to be accounted for to properly characterize the operation of electric propulsion thrusters across different ground test vacuum facilities.

  10. Broadband ground-motion simulation using a hybrid approach

    Science.gov (United States)

    Graves, R.W.; Pitarka, A.

    2010-01-01

    This paper describes refinements to the hybrid broadband ground-motion simulation methodology of Graves and Pitarka (2004), which combines a deterministic approach at low frequencies (f 1 Hz). In our approach, fault rupture is represented kinematically and incorporates spatial heterogeneity in slip, rupture speed, and rise time. The prescribed slip distribution is constrained to follow an inverse wavenumber-squared fall-off and the average rupture speed is set at 80% of the local shear-wave velocity, which is then adjusted such that the rupture propagates faster in regions of high slip and slower in regions of low slip. We use a Kostrov-like slip-rate function having a rise time proportional to the square root of slip, with the average rise time across the entire fault constrained empirically. Recent observations from large surface rupturing earthquakes indicate a reduction of rupture propagation speed and lengthening of rise time in the near surface, which we model by applying a 70% reduction of the rupture speed and increasing the rise time by a factor of 2 in a zone extending from the surface to a depth of 5 km. We demonstrate the fidelity of the technique by modeling the strong-motion recordings from the Imperial Valley, Loma Prieta, Landers, and Northridge earthquakes.

  11. Ground effects on magnetooptic Bragg cells

    Institute of Scientific and Technical Information of China (English)

    WEN Feng; WU BaoJian; QIU Kun

    2008-01-01

    Propagation equation of magnetostatic waves in an arbitrarily magnetized yttrium-iron-garnet/gadolinium-gallium-garnet waveguide coated with perfect metal planes is obtained using the method of the surface magnetic permeability. And ground effects on magnetooptic Bragg cells are investigated with the magnetooptic coupled-mode theory. Theoretical analysis indicates that, diffraction efficiency of guided optical waves can be improved by adjusting the spacing of the metal plane from the ferrite film, and ground effects on the diffraction efficiency will be enhanced using an appropriately tilted bias magnetic field. In the metal clad waveguide system, the magnetostatic wave frequency at which the diffraction efficiency peak is obtained corresponds to the "zero-dispersion" point. Performance of RF spectrum analyzers in this system can also be improved by comparing with the case of the sandwich waveguide. Therefore, magnetooptic Bragg cells with the metal clad waveguide are potential applications to the microwave communication and optical signal processing.

  12. Electrophysiological potentials reveal cortical mechanisms for mental imagery, mental simulation, and grounded (embodied cognition

    Directory of Open Access Journals (Sweden)

    Haline E. Schendan

    2012-09-01

    Full Text Available Grounded cognition theory proposes that cognition, including meaning, is grounded in sensorimotor processing. The mechanism for grounding cognition is mental simulation, which is a type of mental imagery that re-enacts modal processing. To reveal top-down, cortical mechanisms for mental simulation of shape, event-related potentials were recorded to face and object pictures preceded by mental imagery of a picture. Mental imagery of the identical face or object (congruous condition facilitated not only categorical perception (VPP/N170 but also later visual knowledge (N3[00] complex and linguistic knowledge (N400 for faces more than objects, and strategic semantic analysis (late positive complex between 200 and 700 ms. The later effects resembled semantic congruity effects with pictures. Mental imagery also facilitated category decisions, as a P3(00 peaked earlier for congruous than incongruous (other category pictures, resembling the case when identical pictures repeat immediately. Thus mental imagery mimics semantic congruity and immediate repetition priming processes with pictures. Perception control results showed the opposite for faces and were in the same direction for objects: Perceptual repetition adapts (and so impairs processing of perceived faces from categorical perception onwards, but primes processing of objects during categorical perception, visual knowledge processes, and strategic semantic analysis. For both imagery and perception, differences between faces and objects support domain-specificity and indicate that cognition is grounded in modal processing. Altogether, this direct neural evidence reveals that top-down processes of mental imagery sustain an imagistic representation that mimics perception well enough to prime subsequent perception and cognition. This also suggests that automatic mental simulation of the visual shape of faces and objects operates between 200 and 400 ms, and strategic mental simulation operates between

  13. Ground-Motion Simulations of Scenario Earthquakes on the Hayward Fault

    Energy Technology Data Exchange (ETDEWEB)

    Aagaard, B; Graves, R; Larsen, S; Ma, S; Rodgers, A; Ponce, D; Schwartz, D; Simpson, R; Graymer, R

    2009-03-09

    We compute ground motions in the San Francisco Bay area for 35 Mw 6.7-7.2 scenario earthquake ruptures involving the Hayward fault. The modeled scenarios vary in rupture length, hypocenter, slip distribution, rupture speed, and rise time. This collaborative effort involves five modeling groups, using different wave propagation codes and domains of various sizes and resolutions, computing long-period (T > 1-2 s) or broadband (T > 0.1 s) synthetic ground motions for overlapping subsets of the suite of scenarios. The simulations incorporate 3-D geologic structure and illustrate the dramatic increase in intensity of shaking for Mw 7.05 ruptures of the entire Hayward fault compared with Mw 6.76 ruptures of the southern two-thirds of the fault. The area subjected to shaking stronger than MMI VII increases from about 10% of the San Francisco Bay urban area in the Mw 6.76 events to more than 40% of the urban area for the Mw 7.05 events. Similarly, combined rupture of the Hayward and Rodgers Creek faults in a Mw 7.2 event extends shaking stronger than MMI VII to nearly 50% of the urban area. For a given rupture length, the synthetic ground motions exhibit the greatest sensitivity to the slip distribution and location inside or near the edge of sedimentary basins. The hypocenter also exerts a strong influence on the amplitude of the shaking due to rupture directivity. The synthetic waveforms exhibit a weaker sensitivity to the rupture speed and are relatively insensitive to the rise time. The ground motions from the simulations are generally consistent with Next Generation Attenuation ground-motion prediction models but contain long-period effects, such as rupture directivity and amplification in shallow sedimentary basins that are not fully captured by the ground-motion prediction models.

  14. Mixed-field GCR Simulations for Radiobiological Research Using Ground Based Accelerators

    Science.gov (United States)

    Kim, Myung-Hee Y.; Rusek, Adam; Cucinotta, Francis A.

    2014-01-01

    Space radiation is comprised of a large number of particle types and energies, which have differential ionization power from high energy protons to high charge and energy (HZE) particles and secondary neutrons produced by galactic cosmic rays (GCR). Ground based accelerators such as the NASA Space Radiation Laboratory (NSRL) at Brookhaven National Laboratory (BNL) are used to simulate space radiation for radiobiology research and dosimetry, electronics parts, and shielding testing using mono-energetic beams for single ion species. As a tool to support research on new risk assessment models, we have developed a stochastic model of heavy ion beams and space radiation effects, the GCR Event-based Risk Model computer code (GERMcode). For radiobiological research on mixed-field space radiation, a new GCR simulator at NSRL is proposed. The NSRL-GCR simulator, which implements the rapid switching mode and the higher energy beam extraction to 1.5 GeV/u, can integrate multiple ions into a single simulation to create GCR Z-spectrum in major energy bins. After considering the GCR environment and energy limitations of NSRL, a GCR reference field is proposed after extensive simulation studies using the GERMcode. The GCR reference field is shown to reproduce the Z and LET spectra of GCR behind shielding within 20% accuracy compared to simulated full GCR environments behind shielding. A major challenge for space radiobiology research is to consider chronic GCR exposure of up to 3-years in relation to simulations with cell and animal models of human risks. We discuss possible approaches to map important biological time scales in experimental models using ground-based simulation with extended exposure of up to a few weeks and fractionation approaches at a GCR simulator.

  15. Numerical Simulation of the Effect of Preexisting Fault on Land Subsidence and Ground Fissures During Pumping%先存断裂对抽水沉降及地裂缝活动影响的数值模拟

    Institute of Scientific and Technical Information of China (English)

    蒋臻蔚; 彭建兵; 王启耀

    2012-01-01

    The effect of pumping on ground fissures caused by fault is obvious, but its mechanism is rather complicated. Most of the previous corresponding researches are simple qualitative analysis, while numerical simulation and quantitative analysis are few. A new method was adopted to simulate the fault effect on ground fissures during pumping, which is based on Biot seepage and consolidation theory and contact surface element considering the contact relationship of side A and B. The results indicate that pumping could arouse stress change around pumping well, the horizontal earth stress near the well ascend while descend far away from it, causing cracks come into being from above to below when horizontal stress exceed the tensile strength. Additionally, preexisting fault affect the stress redistribution distinctly. Due to the low strength of fault surface, it is easy for stratum to be tore apart or slide along the fault, promoting the activity of ground fissures. In general, the effect of preexisting fault on ground subsidence and fissures includes induction, segregation and amplification.%过度抽取地下水对断层构造型地裂缝的加剧作用是很明显的,但具体的作用机制却很复杂,过去的研究多是简单的定性分析,数值模拟和定量计算少有报道.笔者采用比奥(Biot)固结渗流理论和基于A、B面接触判断的库仑滑动和张裂的接触面单元,对抽水作用下地裂缝的活动进行了数值模拟,初步探讨了抽水活动引发和加剧地裂缝活动的机制.结果表明:抽水作用下抽水井周围水平应力场发生近井区挤压、远井区拉张的变化,当拉张区内的拉应力超过土体抗拉强度时将会出现自上而下的张裂缝;先存断裂的存在将影响应力变化的模式,同时由于断裂的软弱性,使得地层容易沿其发生滑动或拉裂,从而加剧地裂缝的活动;先存断裂对地面沉降和地裂缝具有诱导、隔离和放大的作用.

  16. Improving the simulation of landfast ice by combining tensile strength and a parameterization for grounded ridges

    Science.gov (United States)

    Lemieux, Jean-François; Dupont, Frédéric; Blain, Philippe; Roy, François; Smith, Gregory C.; Flato, Gregory M.

    2016-10-01

    In some coastal regions of the Arctic Ocean, grounded ice ridges contribute to stabilizing and maintaining a landfast ice cover. Recently, a grounding scheme representing this effect on sea ice dynamics was introduced and tested in a viscous-plastic sea ice model. This grounding scheme, based on a basal stress parameterization, improves the simulation of landfast ice in many regions such as in the East Siberian Sea, the Laptev Sea, and along the coast of Alaska. Nevertheless, in some regions like the Kara Sea, the area of landfast ice is systematically underestimated. This indicates that another mechanism such as ice arching is at play for maintaining the ice cover fast. To address this problem, the combination of the basal stress parameterization and tensile strength is investigated using a 0.25° Pan-Arctic CICE-NEMO configuration. Both uniaxial and isotropic tensile strengths notably improve the simulation of landfast ice in the Kara Sea but also in the Laptev Sea. However, the simulated landfast ice season for the Kara Sea is too short compared to observations. This is especially obvious for the onset of the landfast ice season which systematically occurs later in the model and with a slower build up. This suggests that improvements to the sea ice thermodynamics could reduce these discrepancies with the data.

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

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

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

  18. Modeling and Simulation of an Unmanned Ground Vehicle Power System

    Science.gov (United States)

    2014-03-28

    Wilhelm, A. N., Surgenor, B. W., and Pharoah, J. G., “Design and evaluation of a micro-fuel-cell-based power system for a mobile robot ,” Mechatronics ...of Michigan, Ann Arbor, MI, USA bU.S. Army RDECOM-TARDEC, Warren, MI, USA ABSTRACT Long-duration missions challenge ground robot systems with respect...to energy storage and efficient conversion to power on demand. Ground robot systems can contain multiple power sources such as fuel cell, battery and

  19. Study on simulating strong ground motion by fractal stochastic method

    Institute of Scientific and Technical Information of China (English)

    GUO Meng-qiu; WANG Bin; XU Zhao-yong

    2005-01-01

    @@ The time history of strong ground motion can be synthesized by empirical Green's function (EGF) method.Firstly a large seismic event is discretized into a series of subevents; secondly recordings of earthquakes with proper size and spatial distribution are chosen as time history (EGF) of those subevents; finally the EGFs are summated to get the time history of ground motion caused by the large event.

  20. Numerical simulation and experimental validation of aircraft ground deicing model

    OpenAIRE

    2016-01-01

    Aircraft ground deicing plays an important role of guaranteeing the aircraft safety. In practice, most airports generally use as many deicing fluids as possible to remove the ice, which causes the waste of the deicing fluids and the pollution of the environment. Therefore, the model of aircraft ground deicing should be built to establish the foundation for the subsequent research, such as the optimization of the deicing fluid consumption. In this article, the heat balance of the deicing proce...

  1. Simulated Annealing for Ground State Energy of Ionized Donor Bound Excitons in Semiconductors

    Institute of Scientific and Technical Information of China (English)

    YANHai-Qing; TANGChen; LIUMing; ZHANGHao; ZHANGGui-Min

    2004-01-01

    We present a global optimization method, called the simulated annealing, to the ground state energies of excitons. The proposed method does not require the partial derivatives with respect to each variational parameter or solving an eigenequation, so the present method is simpler in software programming than the variational method,and overcomes the major difficulties. The ground state energies of ionized-donor-bound excitons (D+,X) have beencal culated variationally for all values of effective electron-to-hole mass ratio σ. They are compared with those obtained by the variational method. The results obtained demonstrate that the proposed method is simple, accurate, and has more advantages than the traditional methods in calculation.

  2. Simulated Annealing for Ground State Energy of Ionized Donor Bound Excitons in Semiconductors

    Institute of Scientific and Technical Information of China (English)

    YAN Hai-Qing; TANG Chen; LIU Ming; ZHANG Hao; ZHANG Gui-Min

    2004-01-01

    We present a global optimization method, called the simulated annealing, to the ground state energies of excitons. The proposed method does not require the partial derivatives with respect to each variational parameter or solving an eigenequation, so the present method is simpler in software programming than the variational method,and overcomes the major difficulties. The ground state energies of ionized-donor-bound excitons (D+, X) have been calculated variationally for all values of effective electron-to-hole mass ratio σ. They are compared with those obtained by the variational method. The results obtained demonstrate that the proposed method is simple, accurate, and has more advantages than the traditional methods in calculation.

  3. Detect ground motion effects on the trajectory at ATF2

    CERN Document Server

    Rénier, Yves; Garcia, Rogelio

    2011-01-01

    The Accelerator Test Facility 2 (ATF2) commissioning group aims to demonstrate the feasibility of the Beam Delivery System (BDS) of the next linear colliders (ILC and CLIC) as well as to define and to test the tunning methods. As the design vertical beam sizes of the linear colliders are about few nanometers, the stability of the trajectory as well as the control of the aberrations are very critical. The magnet displacements induced by ground motion are large enough for CLIC to perturb the beam stability above requirements. It is planned to measure the displacement of the magnets and implement a feed-forward correcting the effects on the beam trajectory with correctors (dipoles). This article studies the possibility to detect ground motion effects on the beam trajectory at ATF2. Characteristics of the ground motion at ATF2 are presented, the effects of the magnet displacements on the beam trajectory are simulated and an algorithm predicting the induced trajectory fluctuations is evaluated. After the estimated...

  4. Assessment of Simulated Ground Motions in Earthquake Engineering Practice: A Case Study for Duzce (Turkey)

    Science.gov (United States)

    Karimzadeh, Shaghayegh; Askan, Aysegul; Yakut, Ahmet

    2017-07-01

    Simulated ground motions can be used in structural and earthquake engineering practice as an alternative to or to augment the real ground motion data sets. Common engineering applications of simulated motions are linear and nonlinear time history analyses of building structures, where full acceleration records are necessary. Before using simulated ground motions in such applications, it is important to assess those in terms of their frequency and amplitude content as well as their match with the corresponding real records. In this study, a framework is outlined for assessment of simulated ground motions in terms of their use in structural engineering. Misfit criteria are determined for both ground motion parameters and structural response by comparing the simulated values against the corresponding real values. For this purpose, as a case study, the 12 November 1999 Duzce earthquake is simulated using stochastic finite-fault methodology. Simulated records are employed for time history analyses of frame models of typical residential buildings. Next, the relationships between ground motion misfits and structural response misfits are studied. Results show that the seismological misfits around the fundamental period of selected buildings determine the accuracy of the simulated responses in terms of their agreement with the observed responses.

  5. Estimation of beryllium ground state energy by Monte Carlo simulation

    Energy Technology Data Exchange (ETDEWEB)

    Kabir, K. M. Ariful [Department of Physical Sciences, School of Engineering and Computer Science, Independent University, Bangladesh (IUB) Dhaka (Bangladesh); Halder, Amal [Department of Mathematics, University of Dhaka Dhaka (Bangladesh)

    2015-05-15

    Quantum Monte Carlo method represent a powerful and broadly applicable computational tool for finding very accurate solution of the stationary Schrödinger equation for atoms, molecules, solids and a variety of model systems. Using variational Monte Carlo method we have calculated the ground state energy of the Beryllium atom. Our calculation are based on using a modified four parameters trial wave function which leads to good result comparing with the few parameters trial wave functions presented before. Based on random Numbers we can generate a large sample of electron locations to estimate the ground state energy of Beryllium. Our calculation gives good estimation for the ground state energy of the Beryllium atom comparing with the corresponding exact data.

  6. Mathematical model for takeoff simulation of a wing in proximity to the ground

    Science.gov (United States)

    Kinaci, Omer Kemal

    2016-06-01

    Aircraft flying close to the ground benefit from enhanced efficiency owing to decreased induced drag and increased lift. In this study, a mathematical model is developed to simulate the takeoff of a wing near the ground using an Iterative Boundary Element Method (IBEM) and the finite difference scheme. Two stand-alone sub-codes and a mother code, which enables communication between the sub-codes, are developed to solve for the self-excitation of the Wing-In-Ground (WIG) effect. The aerodynamic force exerted on the wing is calculated by the first sub-code using the IBEM, and the vertical displacement of the wing is calculated by the second sub-code using the finite difference scheme. The mother code commands the two sub-codes and can solve for the aerodynamics of the wing and operating height within seconds. The developed code system is used to solve for the force, velocity, and displacement of an NACA6409 wing at a 4° Angle of Attack (AoA) which has various numerical and experimental studies in the literature. The effects of thickness and AoA are then investigated and conclusions were drawn with respect to generated results. The proposed model provides a practical method for understanding the flight dynamics and it is specifically beneficial at the pre-design stages of a WIG effect craft.

  7. Simulation of ground-water flow and transport of chlorinated hydrocarbons at Graces Quarters, Aberdeen Proving Ground, Maryland

    Science.gov (United States)

    Tenbus, Frederick J.; Fleck, William B.

    2001-01-01

    Military activity at Graces Quarters, a former open-air chemical-agent facility at Aberdeen Proving Ground, Maryland, has resulted in ground-water contamination by chlorinated hydrocarbons. As part of a ground-water remediation feasibility study, a three-dimensional model was constructed to simulate transport of four chlorinated hydrocarbons (1,1,2,2-tetrachloroethane, trichloroethene, carbon tetrachloride, and chloroform) that are components of a contaminant plume in the surficial and middle aquifers underlying the east-central part of Graces Quarters. The model was calibrated to steady-state hydraulic head at 58 observation wells and to the concentration of 1,1,2,2-tetrachloroethane in 58 observation wells and 101direct-push probe samples from the mid-1990s. Simulations using the same basic model with minor adjustments were then run for each of the other plume constituents. The error statistics between the simulated and measured concentrations of each of the constituents compared favorably to the error statisticst,1,2,2-tetrachloroethane calibration. Model simulations were used in conjunction with contaminant concentration data to examine the sources and degradation of the plume constituents. It was determined from this that mixed contaminant sources with no ambient degradation was the best approach for simulating multi-species solute transport at the site. Forward simulations were run to show potential solute transport 30 years and 100 years into the future with and without source removal. Although forward simulations are subject to uncertainty, they can be useful for illustrating various aspects of the conceptual model and its implementation. The forward simulation with no source removal indicates that contaminants would spread throughout various parts of the surficial and middle aquifers, with the100-year simulation showing potential discharge areas in either the marshes at the end of the Graces Quarters peninsula or just offshore in the estuaries. The

  8. Zero-Gravity Locomotion Simulators: New Ground-Based Analogs for Microgravity Exercise Simulation

    Science.gov (United States)

    Perusek, Gail P.; DeWitt, John K.; Cavanagh, Peter R.; Grodsinsky, Carlos M.; Gilkey, Kelly M.

    2007-01-01

    Maintaining health and fitness in crewmembers during space missions is essential for preserving performance for mission-critical tasks. NASA's Exercise Countermeasures Project (ECP) provides space exploration exercise hardware and monitoring requirements that lead to devices that are reliable, meet medical, vehicle, and habitat constraints, and use minimal vehicle and crew resources. ECP will also develop and validate efficient exercise prescriptions that minimize daily time needed for completion of exercise yet maximize performance for mission activities. In meeting these mission goals, NASA Glenn Research Center (Cleveland, OH, USA), in collaboration with the Cleveland Clinic (Cleveland, Ohio, USA), has developed a suite of zero-gravity locomotion simulators and associated technologies to address the need for ground-based test analog capability for simulating in-flight (microgravity) and surface (partial-gravity) exercise to advance the health and safety of astronaut crews and the next generation of space explorers. Various research areas can be explored. These include improving crew comfort during exercise, and understanding joint kinematics and muscle activation pattern differences relative to external loading mechanisms. In addition, exercise protocol and hardware optimization can be investigated, along with characterizing system dynamic response and the physiological demand associated with advanced exercise device concepts and performance of critical mission tasks for Exploration class missions. Three zero-gravity locomotion simulators are currently in use and the research focus for each will be presented. All of the devices are based on a supine subject suspension system, which simulates a reduced gravity environment by completely or partially offloading the weight of the exercising test subject s body. A platform for mounting treadmill is positioned perpendicularly to the test subject. The Cleveland Clinic Zero-g Locomotion Simulator (ZLS) utilizes a

  9. Simulation of strong ground motion parameters of the 1 June 2013 Gulf of Suez earthquake, Egypt

    Science.gov (United States)

    Toni, Mostafa

    2017-06-01

    This article aims to simulate the ground motion parameters of the moderate magnitude (ML 5.1) June 1, 2013 Gulf of Suez earthquake, which represents the largest instrumental earthquake to be recorded in the middle part of the Gulf of Suez up to now. This event was felt in all cities located on both sides of the Gulf of Suez, with minor damage to property near the epicenter; however, no casualties were observed. The stochastic technique with the site-dependent spectral model is used to simulate the strong ground motion parameters of this earthquake in the cities located at the western side of the Gulf of Suez and north Red Sea namely: Suez, Ain Sokhna, Zafarana, Ras Gharib, and Hurghada. The presence of many tourist resorts and the increase in land use planning in the considered cities represent the motivation of the current study. The simulated parameters comprise the Peak Ground Acceleration (PGA), Peak Ground Velocity (PGV), and Peak Ground Displacement (PGD), in addition to Pseudo Spectral Acceleration (PSA). The model developed for ground motion simulation is validated by using the recordings of three accelerographs installed around the epicenter of the investigated earthquake. Depending on the site effect that has been determined in the investigated areas by using geotechnical data (e.g., shear wave velocities and microtremor recordings), the investigated areas are classified into two zones (A and B). Zone A is characterized by higher site amplification than Zone B. The ground motion parameters are simulated at each zone in the considered areas. The results reveal that the highest values of PGA, PGV, and PGD are observed at Ras Gharib city (epicentral distance ∼ 11 km) as 67 cm/s2, 2.53 cm/s, and 0.45 cm respectively for Zone A, and as 26.5 cm/s2, 1.0 cm/s, and 0.2 cm respectively for Zone B, while the lowest values of PGA, PGV, and PGD are observed at Suez city (epicentral distance ∼ 190 km) as 3.0 cm/s2, 0.2 cm/s, and 0.05 cm/s respectively for Zone A

  10. System Identification and Automatic Mass Balancing of Ground-Based Three-Axis Spacecraft Simulator

    Science.gov (United States)

    2006-08-01

    System Identification and Automatic Mass Balancing of Ground-Based Three-Axis Spacecraft Simulator Jae-Jun Kim∗ and Brij N. Agrawal † Department of...TITLE AND SUBTITLE System Identification and Automatic Mass Balancing of Ground-Based Three-Axis Spacecraft Simulator 5a. CONTRACT NUMBER 5b...and Dynamics, Vol. 20, No. 4, July-August 1997, pp. 625-632. 6Schwartz, J. L. and Hall, C. D., “ System Identification of a Spherical Air-Bearing

  11. CHEMICAL REACTIONS SIMULATED BY GROUND-WATER-QUALITY MODELS.

    Science.gov (United States)

    Grove, David B.; Stollenwerk, Kenneth G.

    1987-01-01

    Recent literature concerning the modeling of chemical reactions during transport in ground water is examined with emphasis on sorption reactions. The theory of transport and reactions in porous media has been well documented. Numerous equations have been developed from this theory, to provide both continuous and sequential or multistep models, with the water phase considered for both mobile and immobile phases. Chemical reactions can be either equilibrium or non-equilibrium, and can be quantified in linear or non-linear mathematical forms. Non-equilibrium reactions can be separated into kinetic and diffusional rate-limiting mechanisms. Solutions to the equations are available by either analytical expressions or numerical techniques. Saturated and unsaturated batch, column, and field studies are discussed with one-dimensional, laboratory-column experiments predominating. A summary table is presented that references the various kinds of models studied and their applications in predicting chemical concentrations in ground waters.

  12. The SCEC Broadband Platform: Open-Source Software for Strong Ground Motion Simulation and Validation

    Science.gov (United States)

    Goulet, C.; Silva, F.; Maechling, P. J.; Callaghan, S.; Jordan, T. H.

    2015-12-01

    The Southern California Earthquake Center (SCEC) Broadband Platform (BBP) is a carefully integrated collection of open-source scientific software programs that can simulate broadband (0-100Hz) ground motions for earthquakes at regional scales. The BBP scientific software modules implement kinematic rupture generation, low and high-frequency seismogram synthesis using wave propagation through 1D layered velocity structures, seismogram ground motion amplitude calculations, and goodness of fit measurements. These modules are integrated into a software system that provides user-defined, repeatable, calculation of ground motion seismograms, using multiple alternative ground motion simulation methods, and software utilities that can generate plots, charts, and maps. The BBP has been developed over the last five years in a collaborative scientific, engineering, and software development project involving geoscientists, earthquake engineers, graduate students, and SCEC scientific software developers. The BBP can run earthquake rupture and wave propagation modeling software to simulate ground motions for well-observed historical earthquakes and to quantify how well the simulated broadband seismograms match the observed seismograms. The BBP can also run simulations for hypothetical earthquakes. In this case, users input an earthquake location and magnitude description, a list of station locations, and a 1D velocity model for the region of interest, and the BBP software then calculates ground motions for the specified stations. The SCEC BBP software released in 2015 can be compiled and run on recent Linux systems with GNU compilers. It includes 5 simulation methods, 7 simulation regions covering California, Japan, and Eastern North America, the ability to compare simulation results against GMPEs, updated ground motion simulation methods, and a simplified command line user interface.

  13. Algorithms for Model Calibration of Ground Water Simulators

    Science.gov (United States)

    2014-11-20

    cobian, and Jacobian-vector products are computed with a Monte Carlo simulation. This situation differs from the textbook case [5] in that one does not...Anderson acceleration is a natural method for multi-physics coupling (for example subsurface flow, chemistry , and heat transfer) when the individual physics...Online publication 7/12/2014. [11] J. Nance and C. T. Kelley, A sparse interpolation algorithm for dynamical simulations in compu- tational chemistry

  14. Realization of Resistorless Lossless Positive and Negative Grounded Inductor Simulators Using Single ZC-CCCITA

    Directory of Open Access Journals (Sweden)

    N. Herencsar

    2012-04-01

    Full Text Available This paper is in continuation with the very recent work of Prasad et al. [14], wherein new realizations of grounded and floating positive inductor simulator using current differencing transconductance amplifier (CDTA are reported. The focus of the paper is to provide alternate realizations of lossless, both positive and negative inductor simulators (PIS and NIS in grounded form using z-copy current-controlled current inverting transconductance amplifier (ZC-CCCITA, which can be considered as a derivative of CDTA, wherein the current differencing unit (CDU is reduced to a current-controlled current inverting unit. We demonstrate that only a single ZC-CCCITA and one grounded capacitor are sufficient to realize grounded lossless PIS or NIS. The proposed circuits are resistorless whose parameters can be controlled through the bias currents. The workability of the proposed PIS is validated by SPICE simulations on three RLC prototypes.

  15. Real-time simulation of ground displacement by digital accelerograph record

    Institute of Scientific and Technical Information of China (English)

    金星; 马强; 李山有

    2005-01-01

    With the development of accelerograph, strong ground motion data can be widely applied to many fields. Especially, it is an important milestone for strong motion observation to expand application fields into earthquake monitoring that real-time simulation of ground displacement can be obtained by strong motion records for determining three earthquake parameters. For the purpose of application, on the basis of principle of seismic response of single-degree-of-freedom (SDOF) system, this paper presents a suit of formula of simulating ground displacement records by using strong ground motion records with the help of simulator of SDOF system. The research results show that the technique is very efficient and can be widely applied to earthquake monitoring.

  16. Accounting for Fault Roughness in Pseudo-Dynamic Ground-Motion Simulations

    KAUST Repository

    Mai, Paul Martin

    2017-04-03

    Geological faults comprise large-scale segmentation and small-scale roughness. These multi-scale geometrical complexities determine the dynamics of the earthquake rupture process, and therefore affect the radiated seismic wavefield. In this study, we examine how different parameterizations of fault roughness lead to variability in the rupture evolution and the resulting near-fault ground motions. Rupture incoherence naturally induced by fault roughness generates high-frequency radiation that follows an ω−2 decay in displacement amplitude spectra. Because dynamic rupture simulations are computationally expensive, we test several kinematic source approximations designed to emulate the observed dynamic behavior. When simplifying the rough-fault geometry, we find that perturbations in local moment tensor orientation are important, while perturbations in local source location are not. Thus, a planar fault can be assumed if the local strike, dip, and rake are maintained. We observe that dynamic rake angle variations are anti-correlated with the local dip angles. Testing two parameterizations of dynamically consistent Yoffe-type source-time function, we show that the seismic wavefield of the approximated kinematic ruptures well reproduces the radiated seismic waves of the complete dynamic source process. This finding opens a new avenue for an improved pseudo-dynamic source characterization that captures the effects of fault roughness on earthquake rupture evolution. By including also the correlations between kinematic source parameters, we outline a new pseudo-dynamic rupture modeling approach for broadband ground-motion simulation.

  17. Private ground infrastructures for space exploration missions simulations

    Science.gov (United States)

    Souchier, Alain

    2010-06-01

    The Mars Society, a private non profit organisation devoted to promote the red planet exploration, decided to implement simulated Mars habitat in two locations on Earth: in northern Canada on the rim of a meteoritic crater (2000), in a US Utah desert, location of a past Jurassic sea (2001). These habitats have been built with large similarities to actual planned habitats for first Mars exploration missions. Participation is open to everybody either proposing experimentations or wishing only to participate as a crew member. Participants are from different organizations: Mars Society, Universities, experimenters working with NASA or ESA. The general philosophy of the work conducted is not to do an innovative scientific work on the field but to learn how the scientific work is affected or modified by the simulation conditions. Outside activities are conducted with simulated spacesuits limiting the experimenter abilities. Technology or procedures experimentations are also conducted as well as experimentations on the crew psychology and behaviour.

  18. Hydrogeology, simulated ground-water flow, and ground-water quality, Wright-Patterson Air Force Base, Ohio

    Science.gov (United States)

    Dumouchelle, D.H.; Schalk, C.W.; Rowe, G.L.; De Roche, J.T.

    1993-01-01

    Ground water is the primary source of water in the Wright-Patterson Air Force Base area. The aquifer consists of glacial sands and gravels that fill a buried bedrock-valley system. Consolidated rocks in the area consist of poorly permeable Ordovician shale of the Richmondian stage, in the upland areas, the Brassfield Limestone of Silurian age. The valleys are filled with glacial sediments of Wisconsinan age consisting of clay-rich tills and coarse-grained outwash deposits. Estimates of hydraulic conductivity of the shales based on results of displacement/recovery tests range from 0.0016 to 12 feet per day; estimates for the glacial sediments range from less than 1 foot per day to more than 1,000 feet per day. Ground water flow from the uplands towards the valleys and the major rivers in the region, the Great Miami and the Mad Rivers. Hydraulic-head data indicate that ground water flows between the bedrock and unconsolidated deposits. Data from a gain/loss study of the Mad River System and hydrographs from nearby wells reveal that the reach of the river next to Wright-Patterson Air Force Base is a ground-water discharge area. A steady-state, three-dimensional ground-water-flow model was developed to simulate ground-water flow in the region. The model contains three layers and encompasses about 100 square miles centered on Wright-Patterson Air Force Base. Ground water enters the modeled area primarily by river leakage and underflow at the model boundary. Ground water exits the modeled area primarily by flow through the valleys at the model boundaries and through production wells. A model sensitivity analysis involving systematic changes in values of hydrologic parameters in the model indicates that the model is most sensitive to decreases in riverbed conductance and vertical conductance between the upper two layers. The analysis also indicates that the contribution of water to the buried-valley aquifer from the bedrock that forms the valley walls is about 2 to 4

  19. Ground motion-simulations of 1811-1812 New Madrid earthquakes, central United States

    Science.gov (United States)

    Ramirez-Guzman, L.; Graves, Robert; Olsen, Kim B.; Boyd, Oliver; Cramer, Chris H.; Hartzell, Stephen; Ni, Sidao; Somerville, Paul G.; Williams, Robert; Zhong, Jinquan

    2015-01-01

    We performed a suite of numerical simulations based on the 1811–1812 New Madrid seismic zone (NMSZ) earthquakes, which demonstrate the importance of 3D geologic structure and rupture directivity on the ground‐motion response throughout a broad region of the central United States (CUS) for these events. Our simulation set consists of 20 hypothetical earthquakes located along two faults associated with the current seismicity trends in the NMSZ. The hypothetical scenarios range in magnitude from M 7.0 to 7.7 and consider various epicenters, slip distributions, and rupture characterization approaches. The low‐frequency component of our simulations was computed deterministically up to a frequency of 1 Hz using a regional 3D seismic velocity model and was combined with higher‐frequency motions calculated for a 1D medium to generate broadband synthetics (0–40 Hz in some cases). For strike‐slip earthquakes located on the southwest–northeast‐striking NMSZ axial arm of seismicity, our simulations show 2–10 s period energy channeling along the trend of the Reelfoot rift and focusing strong shaking northeast toward Paducah, Kentucky, and Evansville, Indiana, and southwest toward Little Rock, Arkansas. These waveguide effects are further accentuated by rupture directivity such that an event with a western epicenter creates strong amplification toward the northeast, whereas an eastern epicenter creates strong amplification toward the southwest. These effects are not as prevalent for simulations on the reverse‐mechanism Reelfoot fault, and large peak ground velocities (>40  cm/s) are typically confined to the near‐source region along the up‐dip projection of the fault. Nonetheless, these basin response and rupture directivity effects have a significant impact on the pattern and level of the estimated intensities, which leads to additional uncertainty not previously considered in magnitude estimates of the 1811–1812 sequence based only on historical

  20. Non-Stationary Modelling and Simulation of Near-Source Earthquake Ground Motion

    DEFF Research Database (Denmark)

    Skjærbæk, P. S.; Kirkegaard, Poul Henning; Fouskitakis, G. N.

    This paper is concerned with modelling and simulation of near-source earthquake ground motion. Recent studies have revealed that these motions show heavy non-stationary behaviour with very low frequencies dominating parts of the earthquake sequence. Modelling and simulation of this behaviour...... by an epicentral distance of 16 km and measured during the 1979 Imperial valley earthquake in California (USA). The results of the study indicate that while all three approaches can succesfully predict near-source ground motions, the Neural Network based one gives somewhat poorer simulation results....

  1. Non-Stationary Modelling and Simulation of Near-Source Earthquake Ground Motion

    DEFF Research Database (Denmark)

    Skjærbæk, P. S.; Kirkegaard, Poul Henning; Fouskitakis, G. N.

    1997-01-01

    This paper is concerned with modelling and simulation of near-source earthquake ground motion. Recent studies have revealed that these motions show heavy non-stationary behaviour with very low frequencies dominating parts of the earthquake sequence. Modeling and simulation of this behaviour...... by an epicentral distance of 16 km and measured during the 1979 Imperial Valley earthquake in California (U .S .A.). The results of the study indicate that while all three approaches can successfully predict near-source ground motions, the Neural Network based one gives somewhat poorer simulation results....

  2. PHAST--a program for simulating ground-water flow, solute transport, and multicomponent geochemical reactions

    Science.gov (United States)

    Parkhurst, David L.; Kipp, Kenneth L.; Engesgaard, Peter; Charlton, Scott R.

    2004-01-01

    The computer program PHAST simulates multi-component, reactive solute transport in three-dimensional saturated ground-water flow systems. PHAST is a versatile ground-water flow and solute-transport simulator with capabilities to model a wide range of equilibrium and kinetic geochemical reactions. The flow and transport calculations are based on a modified version of HST3D that is restricted to constant fluid density and constant temperature. The geochemical reactions are simulated with the geochemical model PHREEQC, which is embedded in PHAST. PHAST is applicable to the study of natural and contaminated ground-water systems at a variety of scales ranging from laboratory experiments to local and regional field scales. PHAST can be used in studies of migration of nutrients, inorganic and organic contaminants, and radionuclides; in projects such as aquifer storage and recovery or engineered remediation; and in investigations of the natural rock-water interactions in aquifers. PHAST is not appropriate for unsaturated-zone flow, multiphase flow, density-dependent flow, or waters with high ionic strengths. A variety of boundary conditions are available in PHAST to simulate flow and transport, including specified-head, flux, and leaky conditions, as well as the special cases of rivers and wells. Chemical reactions in PHAST include (1) homogeneous equilibria using an ion-association thermodynamic model; (2) heterogeneous equilibria between the aqueous solution and minerals, gases, surface complexation sites, ion exchange sites, and solid solutions; and (3) kinetic reactions with rates that are a function of solution composition. The aqueous model (elements, chemical reactions, and equilibrium constants), minerals, gases, exchangers, surfaces, and rate expressions may be defined or modified by the user. A number of options are available to save results of simulations to output files. The data may be saved in three formats: a format suitable for viewing with a text editor; a

  3. Precision in ground based solar polarimetry: Simulating the role of adaptive optics

    CERN Document Server

    Nagaraju, K

    2012-01-01

    Accurate measurement of polarization in spectral lines is important for the reliable inference of magnetic fields on the Sun. For ground based observations, polarimetric precision is severely limited by the presence of Earth's atmosphere. Atmospheric turbulence (seeing) produces signal fluctuations which combined with the non-simultaneous nature of the measurement process cause intermixing of the Stokes parameters known as seeing induced polarization cross-talk. Previous analysis of this effect (Judge et al., 2004) suggests that cross-talk is reduced not only with increase in modulation frequency but also by compensating the seeing induced image aberrations by an Adaptive Optics (AO) system. However, in those studies the effect of higher order image aberrations than those corrected by the AO system was not taken into account. We present in this paper an analysis of seeing induced cross-talk in the presence of higher order image aberrations through numerical simulation. In this analysis we find that the amount...

  4. Ground-water flow and the potential effects of remediation at Graces Quarters, Aberdeen Proving Ground, Maryland

    Science.gov (United States)

    Tenbus, F.J.; Fleck, W.B.

    1996-01-01

    Ground water in the east-central part of Graces Quarters, a former open-air chemical-agent test facility at Aberdeen Proving Ground, Maryland, is contaminated with chlorinated volatile organic compounds. The U.S. Geological Survey's finite- difference model was used to help understand ground-water flow and simulate the effects of alternative remedial actions to clean up the ground water. Scenarios to simulate unstressed conditions and three extraction well con- figurations were used to compare alternative remedial actions on the contaminant plume. The scenarios indicate that contaminants could migrate from their present location to wetland areas within 10 years under unstressed conditions. Pumping 7 gal/min (gallons per minute) from one well upgradient of the plume will not result in containment or removal of the highest contaminant concentrations. Pumping 7 gal/min from three wells along the central axis of the plume should result in containment and removal of dissolved contami- nants, as should pumping 7 gal/min from three wells at the leading edge of the plume while injecting 7 gal/min back into an upgradient well.

  5. Ground water flow in a desert basin: challenges of simulating transport of dissolved chromium.

    Science.gov (United States)

    Andrews, Charles B; Neville, Christopher J

    2003-01-01

    A large chromium plume that evolved from chromium releases in a valley near the Mojave River was studied to understand the processes controlling fate and migration of chromium in ground water and used as a tracer to study the dynamics of a basin and range ground water system. The valley that was studied is naturally arid with high evapotranspiration such that essentially no precipitation infiltrates to the water table. The dominant natural hydrogeologic processes are recharge to the ground water system from the Mojave River during the infrequent episodes when there is flow in the river, and ground water flow toward a playa lake where the ground water evaporates. Agricultural pumping in the valley from the mid-1930s to the 1970s significantly altered ground water flow conditions by decreasing water levels in the valley by more than 20 m. This pumping declined significantly as a result of dewatering of the aquifer, and water levels have since recovered modestly. The ground water system was modeled using MODFLOW, and chromium transport was simulated using MT3D. Several innovative modifications were made to these modeling programs to simulate important processes in this ground water system. Modifications to MODFLOW include developing a new well package that estimates pumping rates from irrigation wells at each time step based on available drawdown. MT3D was modified to account for mass trapped above the water table when the water table declines beneath nonirrigated areas and to redistribute mass to the system when water levels rise.

  6. Constraint-based Ground contact handling in Humanoid Robotics Simulation

    OpenAIRE

    Martin Moraud, Eduardo; Hale, Joshua G.; Cheng, Gordon

    2008-01-01

    International audience; This paper presents a method for resolving contact in dynamic simulations of articulated figures. It is intended for humanoids with polygonal feet and incorporates Coulomb friction exactly. The proposed technique is based on a constraint selection paradigm. Its implementation offers an exact mode which guarantees correct behavior, as well as an efficiency optimized mode which sacrifices accuracy for a tightly bounded computational burden, thus facilitating batch simula...

  7. NUMERICAL ANALYSIS OF THE GROUND EFFECT ON INSECT HOVERING

    Institute of Scientific and Technical Information of China (English)

    GAO Tong; LIU Nan-sheng; LU Xi-yun

    2008-01-01

    The ground effect on insect hovering is investigated using an immersed boundary-lattice Boltzmann method to solve the two-dimensional incompressible Navier-Stokes equations. A virtual model of an elliptic foil with oscillating translation and rotation near a ground is used. The objective of this study is to deal with the ground effect on the unsteady forces and vortical structures and to get the physical insights in the relevant mechanisms. Two typical insect hovering modes, I.e., normal and dragonfly hovering mode, are examined. Systematic computations have been carried out for some parameters, and the ground effect on the unsteady forces and vortical structures is analyzed.

  8. Strong ground motion simulation of the 2016 Kumamoto earthquake of April 16 using multiple point sources

    Science.gov (United States)

    Nagasaka, Yosuke; Nozu, Atsushi

    2017-02-01

    The pseudo point-source model approximates the rupture process on faults with multiple point sources for simulating strong ground motions. A simulation with this point-source model is conducted by combining a simple source spectrum following the omega-square model with a path spectrum, an empirical site amplification factor, and phase characteristics. Realistic waveforms can be synthesized using the empirical site amplification factor and phase models even though the source model is simple. The Kumamoto earthquake occurred on April 16, 2016, with M JMA 7.3. Many strong motions were recorded at stations around the source region. Some records were considered to be affected by the rupture directivity effect. This earthquake was suitable for investigating the applicability of the pseudo point-source model, the current version of which does not consider the rupture directivity effect. Three subevents (point sources) were located on the fault plane, and the parameters of the simulation were determined. The simulated results were compared with the observed records at K-NET and KiK-net stations. It was found that the synthetic Fourier spectra and velocity waveforms generally explained the characteristics of the observed records, except for underestimation in the low frequency range. Troughs in the observed Fourier spectra were also well reproduced by placing multiple subevents near the hypocenter. The underestimation is presumably due to the following two reasons. The first is that the pseudo point-source model targets subevents that generate strong ground motions and does not consider the shallow large slip. The second reason is that the current version of the pseudo point-source model does not consider the rupture directivity effect. Consequently, strong pulses were not reproduced enough at stations northeast of Subevent 3 such as KMM004, where the effect of rupture directivity was significant, while the amplitude was well reproduced at most of the other stations. This

  9. Radiative and temperature effects of aerosol simulated by the COSMO-Ru model for different atmospheric conditions and their testing against ground-based measurements and accurate RT simulations

    Science.gov (United States)

    Chubarova, Nataly; Poliukhov, Alexei; Shatunova, Marina; Rivin, Gdali; Becker, Ralf; Muskatel, Harel; Blahak, Ulrich; Kinne, Stefan; Tarasova, Tatiana

    2017-04-01

    We use the operational Russian COSMO-Ru weather forecast model (Ritter and and Geleyn, 1991) with different aerosol input data for the evaluation of radiative and temperature effects of aerosol in different atmospheric conditions. Various aerosol datasets were utilized including Tegen climatology (Tegen et al., 1997), updated Macv2 climatology (Kinne et al., 2013), Tanre climatology (Tanre et al., 1984) as well as the MACC data (Morcrette et al., 2009). For clear sky conditions we compare the radiative effects from the COSMO-Ru model over Moscow (55.7N, 37.5E) and Lindenberg/Falkenberg sites (52.2N, 14.1E) with the results obtained using long-term aerosol measurements. Additional tests of the COSMO RT code were performed against (FC05)-SW model (Tarasova T.A. and Fomin B.A., 2007). The overestimation of about 5-8% of COSMO RT code was obtained. The study of aerosol effect on temperature at 2 meters has revealed the sensitivity of about 0.7-1.1 degree C per 100 W/m2 change in shortwave net radiation due to aerosol variations. We also discuss the radiative impact of urban aerosol properties according to the long-term AERONET measurements in Moscow and Moscow suburb as well as long-term aerosol trends over Moscow from the measurements and Macv2 dataset. References: Kinne, S., O'Donnel D., Stier P., et al., J. Adv. Model. Earth Syst., 5, 704-740, 2013. Morcrette J.-J.,O. Boucher, L. Jones, eet al, J.GEOPHYS. RES.,VOL. 114, D06206, doi:10.1029/2008JD011235, 2009. Ritter, B. and Geleyn, J., Monthly Weather Review, 120, 303-325, 1992. Tanre, D., Geleyn, J., and Slingo, J., A. Deepak Publ., Hampton, Virginia, 133-177, 1984. Tarasova, T., and Fomin, B., Journal of Atmospheric and Oceanic Technology, 24, 1157-1162, 2007. Tegen, I., Hollrig, P., Chin, M., et al., Journal of Geophysical Research- Atmospheres, 102, 23895-23915, 1997.

  10. Simulated effects of ground-water withdrawals and artificial recharge on discharge to streams, springs, and riparian vegetation in the Sierra Vista Subwatershed of the Upper San Pedro Basin, southeastern Arizona

    Science.gov (United States)

    Leake, Stanley A.; Pool, Donald R.; Leenhouts, James M.

    2008-01-01

    In the context of ground-water resources, “capture” or “streamflow depletion” refers to withdrawal-induced changes in inflow to or outflow from an aquifer. These concepts are helpful in understanding the effects of long-term development of ground-water resources. For the Upper San Pedro Basin in Arizona, USA and Sonora, Mexico, a recently developed ground-water flow model is available to help quantify capture of water from the river and riparian system. A common method of analysis is to compute curves of capture and aquifer-storage change for a range of time at select points of interest. This study, however, presents results of a method to show spatial distributions of total change in inflow and outflow from withdrawal or injection for select times of interest. The mapped areal distributions show the effect of a single well in terms of the ratio of the change in boundary flow rate to rate of withdrawal or injection by the well. To the extent that the system responds linearly to ground-water withdrawal or injection, fractional responses in the mapped distributions can be used to quantify response for any withdrawal or injection rate. Capture distributions calculated using the Upper San Pedro model include response to (1) withdrawal in the lower basin-fill aquifer for times of 10 and 50 years following the initiation of pumping from predevelopment conditions and (2) artificial recharge to the water table in the area underlain by the lower basin-fill aquifer after 10 and 50 years. The mapped distributions show that response to withdrawals and injections is greatest near the river/riparian system. Presence of clay layers in the vertical interval between withdrawal locations and the river/riparian system, however, can delay the response.

  11. Radiological safety studies on ground disposal of low-level radioactive wastes. Environmental simulation test

    Energy Technology Data Exchange (ETDEWEB)

    Wadachi, Yoshiki; Yamamoto, Tadatoshi; Takebe, Shinichi; Ohnuki, Toshihiko; Washio, Masakazu (Japan Atomic Energy Research Inst., Tokai, Ibaraki. Tokai Research Establishment)

    1982-03-01

    As the method of disposing low level radioactive wastes on land, the underground disposal method disposing the wastes in the structures constructed underground near the ground surface has been investigated as a feasible method. In order to contribute to the environmental safety assessment for this underground disposal method, environmental simulation test is planned at present, in which earth is sampled in the undisturbed state, and the behavior of radioactive nuclides is examined. The testing facilities are to be constructed in Japan Atomic Energy Research Institute from fiscal 1981. First, the research made so far concerning the movement of radioactive nuclides in airing layer and aquifer which compose natural barrier is outlined. As for the environmental simulation test, the necessity and method of the test, earth sampling, the underground simulation facility and the contribution to environmental safety assessment are explained. By examining the movement of radioactive nuclides through natural barrier and making the effective mddel for the underground movement of radioactive nuclides, the environmental safety assessment for the disposal can be performed to obtain the national consensus.

  12. General and Localized corrosion of Austenitic and Borated Stainless Steels in Simulated Concentrated Ground Waters

    Energy Technology Data Exchange (ETDEWEB)

    D. Fix; J. Estill; L. Wong; R. Rebak

    2004-05-28

    Boron containing stainless steels are used in the nuclear industry for applications such as spent fuel storage, control rods and shielding. It was of interest to compare the corrosion resistance of three borated stainless steels with standard austenitic alloy materials such as type 304 and 316 stainless steels. Tests were conducted in three simulated concentrated ground waters at 90 C. Results show that the borated stainless were less resistant to corrosion than the witness austenitic materials. An acidic concentrated ground water was more aggressive than an alkaline concentrated ground water.

  13. General and Localized Corrosion of Austenitic And Borated Stainless Steels in Simulated Concentrated Ground Waters

    Energy Technology Data Exchange (ETDEWEB)

    Estill, J C; Rebak, R B; Fix, D V; Wong, L L

    2004-03-11

    Boron containing stainless steels are used in the nuclear industry for applications such as spent fuel storage, control rods and shielding. It was of interest to compare the corrosion resistance of three borated stainless steels with standard austenitic alloy materials such as type 304 and 316 stainless steels. Tests were conducted in three simulated concentrated ground waters at 90 C. Results show that the borated stainless were less resistant to corrosion than the witness austenitic materials. An acidic concentrated ground water was more aggressive than an alkaline concentrated ground water.

  14. A refined computer program for the transient simulation of ground coupled heat pump systems

    Science.gov (United States)

    Andrews, J. W.; Metz, P. D.; Saunders, J. H.

    1983-04-01

    The use of the earth as a heat source/sink or storage medium for various heat pump based space conditioning systems were investigated. A computer program ground coupled system (GROCS) was developed to model the behavior of ground coupling devices. The GROCS was integrated with TRNSYS, the solar system simulation program, to permit the simulation of complete ground coupled heat pump systems. Experimental results were compared to GROCS simulation results for model validation. It is found that the model has considerable validity. A refined version of the GROCS-TRNSYS program developed to model vertical or horizontal earth coil systems, which considers system cycling is described. The design of the program and its interaction with TRNSYS are discussed.

  15. Estimating the ground-state probability of a quantum simulation with product-state measurements

    Directory of Open Access Journals (Sweden)

    Bryce eYoshimura

    2015-10-01

    Full Text Available .One of the goals in quantum simulation is to adiabatically generate the ground state of a complicated Hamiltonian by starting with the ground state of a simple Hamiltonian and slowly evolving the system to the complicated one. If the evolution is adiabatic and the initial and final ground states are connected due to having the same symmetry, then the simulation will be successful. But in most experiments, adiabatic simulation is not possible because it would take too long, and the system has some level of diabatic excitation. In this work, we quantify the extent of the diabatic excitation even if we do not know {it a priori} what the complicated ground state is. Since many quantum simulator platforms, like trapped ions, can measure the probabilities to be in a product state, we describe techniques that can employ these simple measurements to estimate the probability of being in the ground state of the system after the diabatic evolution. These techniques do not require one to know any properties about the Hamiltonian itself, nor to calculate its eigenstate properties. All the information is derived by analyzing the product-state measurements as functions of time.

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

    Institute of Scientific and Technical Information of China (English)

    ZHAO Zhixin; XU Jiren; Ryuji Kubota

    2004-01-01

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

  17. Earthquake Ground Motion in the Valley of Mexico: Basin Effects

    Science.gov (United States)

    Ramirez, L.; Contreras, M.; Bielak, J.; Aguirre, J.

    2007-12-01

    We present a study of the ground motion and resulting amplification in the Mexico City Basin due to strong earthquakes in the Mexican Pacific Coast. We propose an approximation of the regional structure and Mexico City's basin and analyze their response to two shallow earthquakes generated near the coast. We compare two sets of three dimensional simulations: the first includes a soft structure similar in shape and properties to the Valley of Mexico, while the second excludes the soft soil deposits. Our 3D computations, with a maximum resolution of 0.75 Hz, reproduce the amplitude and long durations characteristics usually observed in the basin. We confirm that stations inside the Mexican Volcanic Belt experience amplification. In the frequency band 0.2-0.4 Hz additional amplification occurs inside the valley due to the shallow soil deposits in the lake bed region. We compare the normalized durations of the ground motion at several stations against observed data, and speculate on the durations of the soil motion as being a local effect due to the basin's shape and low velocities.

  18. Simulation of Ground Winds Time Series for the NASA Crew Launch Vehicle (CLV)

    Science.gov (United States)

    Adelfang, Stanley I.

    2008-01-01

    Simulation of wind time series based on power spectrum density (PSD) and spectral coherence models for ground wind turbulence is described. The wind models, originally developed for the Shuttle program, are based on wind measurements at the NASA 150-m meteorological tower at Cape Canaveral, FL. The current application is for the design and/or protection of the CLV from wind effects during on-pad exposure during periods from as long as days prior to launch, to seconds or minutes just prior to launch and seconds after launch. The evaluation of vehicle response to wind will influence the design and operation of constraint systems for support of the on-pad vehicle. Longitudinal and lateral wind component time series are simulated at critical vehicle locations. The PSD model for wind turbulence is a function of mean wind speed, elevation and temporal frequency. Integration of the PSD equation over a selected frequency range yields the variance of the time series to be simulated. The square root of the PSD defines a low-pass filter that is applied to adjust the components of the Fast Fourier Transform (FFT) of Gaussian white noise. The first simulated time series near the top of the launch vehicle is the inverse transform of the adjusted FFT. Simulation of the wind component time series at the nearest adjacent location (and all other succeeding next nearest locations) is based on a model for the coherence between winds at two locations as a function of frequency and separation distance, where the adjacent locations are separated vertically and/or horizontally. The coherence function is used to calculate a coherence weighted FFT of the wind at the next nearest location, given the FFT of the simulated time series at the previous location and the essentially incoherent FFT of the wind at the selected location derived a priori from the PSD model. The simulated time series at each adjacent location is the inverse Fourier transform of the coherence weighted FFT. For a selected

  19. Running On-Demand Strong Ground Motion Simulations with the Second-Generation Broadband Platform

    Science.gov (United States)

    Callaghan, S.; Maechling, P. J.; Graves, R. W.; Somerville, P. G.; Collins, N.; Olsen, K. B.; Imperatori, W.; Jones, M.; Archuleta, R. J.; Schmedes, J.; Jordan, T. H.; Broadband Platform Working Group

    2010-12-01

    We have developed the second-generation Southern California Earthquake Center (SCEC) Broadband Platform by integrating scientific modeling codes into a system capable of computing broadband seismograms (0-10 Hz) for historical and scenario earthquakes in California. The SCEC Broadband Platform is a collaborative software development project involving SCEC researchers, graduate students, and the SCEC Community Modeling Environment (SCEC/CME) software development group. SCEC scientific groups have contributed software modules to the Broadband Platform including rupture generation, low-frequency deterministic seismogram synthesis, high-frequency stochastic seismogram synthesis, and non-linear site effects. These complex scientific codes have been integrated into a system that supports easy on-demand computation of broadband seismograms. The SCEC Broadband Platform is designed to be used by both scientific and engineering researchers familiar with ground motion simulations. Users may calculate broadband seismograms for both historical earthquakes (validation events including Northridge, Loma Prieta, and Landers) and user-defined earthquakes. Users may select among various codebases for rupture generation, low-frequency synthesis, high-frequency synthesis, and incorporation of site effects, with the option of running a goodness-of-fit comparison against observed or simulated seismograms. The platform produces a variety of data products, including broadband seismograms, rupture visualizations, and goodness-of-fit plots. The Broadband Platform was implemented using software development best practices that support software accuracy, reliability, and ease of use, including version control, user documentation, acceptance tests, and formal software releases. Users can install the platform on their own machine, verify that it is installed correctly, and run their own simulations on demand. The Broadband Platform enables users to run complex ground motion modeling codes without

  20. Numerical simulation of atmospheric diffusion of radon emitted from ground uranium tailings impoundment and environmental effects%平地型铀尾矿库氡大气扩散数值模拟及环境效应分析

    Institute of Scientific and Technical Information of China (English)

    刘振昊; 彭小勇; 熊军; 万芬; 谢清芳

    2012-01-01

    The article attempts to introduce a numerical simulation model of atmospheric diffusion of radon emitted from ground tailings impoundment and analyze environmental effects. The results of our simulation show that radon concentration tends to decrease continually and turn to be smaller with the increase of the air speed and the defusing distance. When U10 = 0.5 m/s, the accumulated radon would defuse at the downwind area within the maximum distance of 5 000 m. And, when the air speed increased to Ul0 = 2.0 m/s, the range would reduce to 2 500 m in the same downwind area. As a result, the local pollution would become serious. However, if the air speed tends to increase, the radon diffusion and pollution would spread farther and the pollution the area suffers tends to be slighter. When U10 = 0.5 m/s, the radon concentration of the tailings at the downwind area would be 43% higher than the highest radon concentration under other air speeds. Thus, it can be seen that the air speed may have a great effect on radon diffusion. The regulations of radon radiation and environmental protection in uranium mining and milling ( GB 23727-2009) area suggest that the distance between the tailings boundary and the residential area should be separated at least no less than 800 m, which can be tested by using the annual effective dose of the public evaluation for its surrounding effect. The analysts of the annual effective dose caused by the radon tailings at the downwind area shows that there exists a great relation between the protection distance of tailings and the local air speed. When Ul0 = 0.5 m/s, f= 12.6% , the protection distance of the tailings impoundment should be greater than that of standard distance under the circumstance of the prevailing wind direction and the wind frequency. But, when U10 = 1.0 m/s, 1.5 m/s, 2.0 m/s, the protection distance of the tailings can be made within 800 m. In addition, there also exists very close relation between the protection distance of

  1. Simulation of ground-water flow in the Albuquerque Basin, central New Mexico, 1901-95, with projections to 2020

    Science.gov (United States)

    Kernodle, J.M.

    1998-01-01

    The ground-water-flow model of the Albuquerque Basin (Kernodle, J.M., McAda, D.P., and Thorn, C.R., 1995, Simulation of ground-water flow in the Albuquerque Basin, central New Mexico, with projections to 2020: U.S. Geological Survey Water-Resources Investigations Report 94-4251, 114 p.) was updated to include new information on the hydrogeologic framework (Hawley, J.W., Haase, C.S., and Lozinsky, R.P., 1995, An underground view of the Albuquerque Basin: Proceedings of the 39th Annual New Mexico Water Conference, November 3-4, 1994, p. 37-55). An additional year of ground-water-withdrawal data was appended to the simulation of the historical period and incorporated into the base for future projections to the year 2020. The revised model projects the simulated ground-water levels associated with an aerally enlarged occurrence of the relatively high hydraulic conductivity in the upper part of the Santa Fe Group east and west of the Rio Grande in the Albuquerque area and north to Bernalillo. Although the differences between the two model versions are substantial, the revised model does not contradict any previous conclusions about the effect of City of Albuquerque ground-water withdrawals on flow in the Rio Grande or the net benefits of an effort to conserve ground water. Recent revisions to the hydrogeologic model (Hawley, J.W., Haneberg, W.C., and Whitworth, P.M., in press, Hydrogeologic investigations in the Albuquerque Basin, central New Mexico, 1992-1995: Socorro, New Mexico Bureau of Mines and Mineral Resources Open- File Report 402) of the Albuquerque Basin eventually will require that this model version also be revised and updated.

  2. SCENARIO AND TARGET SIMULATION FOR A GROUND BASED MULTIFUNCTION PHASED ARRAY RADAR

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    This paper describes a scenario and target simulation which operates in non real-time to provide full closed-loop operation of the ground based multifunction phased array radar simulation system in support of ballistic missile defence experiments against countermeasure.By simulating the target scattering signature and dynamical signature,this scenario and target simulation provide re- alistic scenario source to evaluate the system performance of multifunction phased array radar,and the key algorithms verification and validation such as target tracking,multi-target imaging and target recognition.

  3. Performance and Stability of a Winged Vehicle in Ground Effect

    CERN Document Server

    de Divitiis, Nicola

    2009-01-01

    Present work deals with the dynamics of vehicles which intentionally operate in the ground proximity. The dynamics in ground effect is influenced by the vehicle orientation with respect to the ground, since the aerodynamic force and moment coefficients, which in turn depend on height and angle of attack, also vary with the Euler angles. This feature, usually neglected in the applications, can be responsible for sizable variations of the aircraft performance and stability. A further effect, caused by the sink rate, determines unsteadiness that modifies the aerodynamic coefficients. In this work, an analytical formulation is proposed for the force and moment calculation in the presence of the ground and taking the aircraft attitude and sink rate into account. The aerodynamic coefficients are firstly calculated for a representative vehicle and its characteristics in ground effect are investigated. Performance and stability characteristics are then discussed with reference to significant equilibrium conditions, w...

  4. Ground motions and its effects in accelerator design

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, G.E.

    1984-07-01

    This lecture includes a discussion of types of motion, frequencies of interest, measurements at SLAC, some general comments regarding local sources of ground motion at SLAC, and steps that can be taken to minimize the effects of ground motion on accelerators. (GHT)

  5. Validation of Broadband Ground Motion Simulations for Japanese Crustal Earthquakes by the Recipe

    Science.gov (United States)

    Iwaki, A.; Maeda, T.; Morikawa, N.; Miyake, H.; Fujiwara, H.

    2015-12-01

    The Headquarters for Earthquake Research Promotion (HERP) of Japan has organized the broadband ground motion simulation method into a standard procedure called the "recipe" (HERP, 2009). In the recipe, the source rupture is represented by the characterized source model (Irikura and Miyake, 2011). The broadband ground motion time histories are computed by a hybrid approach: the 3-D finite-difference method (Aoi et al. 2004) and the stochastic Green's function method (Dan and Sato, 1998; Dan et al. 2000) for the long- (> 1 s) and short-period (structure model. As the engineering significance of scenario earthquake ground motion prediction is increasing, thorough verification and validation are required for the simulation methods. This study presents the self-validation of the recipe for two MW6.6 crustal events in Japan, the 2000 Tottori and 2004 Chuetsu (Niigata) earthquakes. We first compare the simulated velocity time series with the observation. Main features of the velocity waveforms, such as the near-fault pulses and the large later phases on deep sediment sites are well reproduced by the simulations. Then we evaluate 5% damped pseudo acceleration spectra (PSA) in the framework of the SCEC Broadband Platform (BBP) validation (Dreger et al. 2015). The validation results are generally acceptable in the period range 0.1 - 10 s, whereas those in the shortest period range (0.01-0.1 s) are less satisfactory. We also evaluate the simulations with the 1-D velocity structure models used in the SCEC BBP validation exercise. Although the goodness-of-fit parameters for PSA do not significantly differ from those for the 3-D velocity structure model, noticeable differences in velocity waveforms are observed. Our results suggest the importance of 1) well-constrained 3-D velocity structure model for broadband ground motion simulations and 2) evaluation of time series of ground motion as well as response spectra.

  6. Simulated constant-head boundary for the transient ground-water flow model, Death Valley regional ground-water flow system, Nevada and California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This digital data set represents the constant head-boundary used to simulate ground-water inflow or outflow at the lateral boundary of the Death Valley regional...

  7. Simulated constant-head boundary for the transient ground-water flow model, Death Valley regional ground-water flow system, Nevada and California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This digital data set represents the constant head-boundary used to simulate ground-water inflow or outflow at the lateral boundary of the Death Valley regional...

  8. A Critical Review of the Transport and Decay of Wake Vortices in Ground Effect

    Science.gov (United States)

    Sarpkaya, T.

    2004-01-01

    This slide presentation reviews the transport and decay of wake vortices in ground effect and cites a need for a physics-based parametric model. The encounter of a vortex with a solid body is always a complex event involving turbulence enhancement, unsteadiness, and very large gradients of velocity and pressure. Wake counter in ground effect is the most dangerous of them all. The interaction of diverging, area-varying, and decaying aircraft wake vortices with the ground is very complex because both the vortices and the flow field generated by them are altered to accommodate the presence of the ground (where there is very little room to maneuver) and the background turbulent flow. Previous research regarding vortex models, wake vortex decay mechanisms, time evolution within in ground effect of a wake vortex pair, laminar flow in ground effect, and the interaction of the existing boundary layer with a convected vortex are reviewed. Additionally, numerical simulations, 3-dimensional large-eddy simulations, a probabilistic 2-phase wake vortex decay and transport model and a vortex element method are discussed. The devising of physics-based, parametric models for the prediction of (operational) real-time response, mindful of the highly three-dimensional and unsteady structure of vortices, boundary layers, atmospheric thermodynamics, and weather convective phenomena is required. In creating a model, LES and field data will be the most powerful tools.

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

  13. Simulation of a ground-layer adaptive optics system for the Kunlun Dark Universe Survey Telescope

    Institute of Scientific and Technical Information of China (English)

    Peng Jia; Sijiong Zhang

    2013-01-01

    Ground Layer Adaptive Optics (GLAO) is a recently developed technique extensively applied to ground-based telescopes,which mainly compensates for the wavefront errors induced by ground-layer turbulence to get an appropriate point spread function in a wide field of view.The compensation results mainly depend on the turbulence distribution.The atmospheric turbulence at Dome A in the Antarctic is mainly distributed below 15 meters,which is an ideal site for applications of GLAO.The GLAO system has been simulated for the Kunlun Dark Universe Survey Telescope,which will be set up at Dome A,and uses a rotating mirror to generate several laser guide stars and a wavefront sensor with a wide field of view to sequentially measure the wavefronts from different laser guide stars.The system is simulated on a computer and parameters of the system are given,which provide detailed information about the design of a practical GLAO system.

  14. The Grounded Theory Method: Deconstruction and Reconstruction in a Human Patient Simulation Context

    Directory of Open Access Journals (Sweden)

    Brian Parker PhD

    2011-03-01

    Full Text Available Certain modes of qualitative inquiry, such as grounded theory, can serve to uncover the abstract processes and broad conceptual themes influencing the personal experiences of undergraduate nursing students encountering clinical scenarios utilizing human patient simulators (HPS. To date insufficient research has been conducted to uncover the basic social-psychological processes encountered by students as they engage in a HPS-based clinical scenario. The authors assert that HPS-based learning experiences are in reality social endeavors that lead to the creation of socially negotiated knowledge and meanings relevant to the adult learner. To understand how grounded theory is suited to deriving answers to these questions, an analysis of the theoretical and philosophical foundations of grounded theory is undertaken. This critical analysis concludes with a discussion of specific considerations to be reflected upon by researchers when applying the inductively derived method of grounded theory in uncovering the social processes that occur within HPS-based clinical scenarios.

  15. Electromagnetic simulators for Ground Penetrating Radar applications developed in COST Action TU1208

    Science.gov (United States)

    Pajewski, Lara; Giannopoulos, Antonios; Warren, Craig; Antonijevic, Sinisa; Doric, Vicko; Poljak, Dragan

    2017-04-01

    Founded in 1971, COST (European COoperation in Science and Technology) is the first and widest European framework for the transnational coordination of research activities. It operates through Actions, science and technology networks with a duration of four years. The main objective of the COST Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar" (4 April 2013 - 3 October 2017) is to exchange and increase knowledge and experience on Ground-Penetrating Radar (GPR) techniques in civil engineering, whilst promoting in Europe a wider use of this technique. Research activities carried out in TU1208 include all aspects of the GPR technology and methodology: design, realization and testing of radar systems and antennas; development and testing of surveying procedures for the monitoring and inspection of structures; integration of GPR with other non-destructive testing approaches; advancement of electromagnetic-modelling, inversion and data-processing techniques for radargram analysis and interpretation. GPR radargrams often have no resemblance to the subsurface or structures over which the profiles were recorded. Various factors, including the innate design of the survey equipment and the complexity of electromagnetic propagation in composite scenarios, can disguise complex structures recorded on reflection profiles. Electromagnetic simulators can help to understand how target structures get translated into radargrams. They can show the limitations of GPR technique, highlight its capabilities, and support the user in understanding where and in what environment GPR can be effectively used. Furthermore, electromagnetic modelling can aid the choice of the most proper GPR equipment for a survey, facilitate the interpretation of complex datasets and be used for the design of new antennas. Electromagnetic simulators can be employed to produce synthetic radargrams with the purposes of testing new data-processing, imaging and inversion algorithms, or assess

  16. Numerical simulation of vertical ground-water flux of the Rio Grande from ground-water temperature profiles, central New Mexico

    Science.gov (United States)

    Bartolino, James R.; Niswonger, Richard G.

    1999-01-01

    An important gap in the understanding of the hydrology of the Middle Rio Grande Basin, central New Mexico, is the rate at which water from the Rio Grande recharges the Santa Fe Group aquifer system. Several methodologies-including use of the Glover-Balmer equation, flood pulses, and channel permeameters- have been applied to this problem in the Middle Rio Grande Basin. In the work presented here, ground-water temperature profiles and ground-water levels beneath the Rio Grande were measured and numerically simulated at four sites. The direction and rate of vertical ground-water flux between the river and underlying aquifer was simulated and the effective vertical hydraulic conductivity of the sediments underlying the river was estimated through model calibration. Seven sets of nested piezometers were installed during July and August 1996 at four sites along the Rio Grande in the Albuquerque area, though only four of the piezometer nests were simulated. In downstream order, these four sites are (1) the Bernalillo site, upstream from the New Mexico State Highway 44 bridge in Bernalillo (piezometer nest BRN02); (2) the Corrales site, upstream from the Rio Rancho sewage treatment plant in Rio Rancho (COR01); (3) the Paseo del Norte site, upstream from the Paseo del Norte bridge in Albuquerque (PDN01); and (4) the Rio Bravo site, upstream from the Rio Bravo bridge in Albuquerque (RBR01). All piezometers were completed in the inner-valley alluvium of the Santa Fe Group aquifer system. Ground-water levels and temperatures were measured in the four piezometer nests a total of seven times in the 24-month period from September 1996 through August 1998. The flux between the surface- and ground-water systems at each of the field sites was quantified by one-dimensional numerical simulation of the water and heat exchange in the subsurface using the heat and water transport model VS2DH. Model calibration was aided by the use of PEST, a model-independent computer program that uses

  17. An assembly model for simulation of large-scale ground water flow and transport.

    Science.gov (United States)

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

    2008-01-01

    When managing large-scale ground water contamination problems, it is often necessary to model flow and transport using finely discretized domains--for instance (1) to simulate flow and transport near a contamination source area or in the area where a remediation technology is being implemented; (2) to account for small-scale heterogeneities; (3) to represent ground water-surface water interactions; or (4) some combination of these scenarios. A model with a large domain and fine-grid resolution will need extensive computing resources. In this work, a domain decomposition-based assembly model implemented in a parallel computing environment is developed, which will allow efficient simulation of large-scale ground water flow and transport problems using domain-wide grid refinement. The method employs common ground water flow (MODFLOW) and transport (RT3D) simulators, enabling the solution of almost all commonly encountered ground water flow and transport problems. The basic approach partitions a large model domain into any number of subdomains. Parallel processors are used to solve the model equations within each subdomain. Schwarz iteration is applied to match the flow solution at the subdomain boundaries. For the transport model, an extended numerical array is implemented to permit the exchange of dispersive and advective flux information across subdomain boundaries. The model is verified using a conventional single-domain model. Model simulations demonstrate that the proposed model operated in a parallel computing environment can result in considerable savings in computer run times (between 50% and 80%) compared with conventional modeling approaches and may be used to simulate grid discretizations that were formerly intractable.

  18. Parasitic Effects of Grounding Paths on Common-Mode EMI Filter's Performance in Power Electronics Systems

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Shuo [ORNL; Maillet, Yoann [Virginia Polytechnic Institute and State University (Virginia Tech); Wang, Fei [ORNL; Lai, Rixin [General Electric; Luo, Fang [Virginia Polytechnic Institute and State University (Virginia Tech); Boroyevich, Dushan [Virginia Polytechnic Institute and State University (Virginia Tech)

    2010-01-01

    High-frequency common-mode (CM) electromagnetic-interference (EMI) noise is difficult to suppress in electronics systems. EMI filters are used to suppress CM noise, but their performance is greatly affected by the parasitic effects of the grounding paths. In this paper, the parasitic effects of the grounding paths on an EMI filter's performance are investigated in a motor-drive system. The effects of the mutual inductance between two grounding paths are explored. Guidelines for the grounding of CM EMI filters are derived. Simulations and experiments are finally carried out to verify the theoretical analysis.

  19. Real-Time and High-Fidelity Simulation Environment for Autonomous Ground Vehicle Dynamics

    Science.gov (United States)

    Cameron, Jonathan; Myint, Steven; Kuo, Calvin; Jain, Abhi; Grip, Havard; Jayakumar, Paramsothy; Overholt, Jim

    2013-01-01

    This paper reports on a collaborative project between U.S. Army TARDEC and Jet Propulsion Laboratory (JPL) to develop a unmanned ground vehicle (UGV) simulation model using the ROAMS vehicle modeling framework. Besides modeling the physical suspension of the vehicle, the sensing and navigation of the HMMWV vehicle are simulated. Using models of urban and off-road environments, the HMMWV simulation was tested in several ways, including navigation in an urban environment with obstacle avoidance and the performance of a lane change maneuver.

  20. Towards photonic quantum simulation of ground states of frustrated Heisenberg spin systems.

    Science.gov (United States)

    Ma, Xiao-song; Dakić, Borivoje; Kropatschek, Sebastian; Naylor, William; Chan, Yang-hao; Gong, Zhe-xuan; Duan, Lu-ming; Zeilinger, Anton; Walther, Philip

    2014-01-07

    Photonic quantum simulators are promising candidates for providing insight into other small- to medium-sized quantum systems. Recent experiments have shown that photonic quantum systems have the advantage to exploit quantum interference for the quantum simulation of the ground state of Heisenberg spin systems. Here we experimentally characterize this quantum interference at a tuneable beam splitter and further investigate the measurement-induced interactions of a simulated four-spin system by comparing the entanglement dynamics using pairwise concurrence. We also study theoretically a four-site square lattice with next-nearest neighbor interactions and a six-site checkerboard lattice, which might be in reach of current technology.

  1. Approach to simulation effectiveness

    CSIR Research Space (South Africa)

    Goncalves, DPD

    2006-07-01

    Full Text Available ? The context and purpose of simulation are important in answering the question. If the simulation is viewed as a system, it follows that it has stakeholders and requirements originating from the creating system. An important result is that measures...

  2. Effects of Ground Motion Input on the Derived Fragility Functions: Case study of 2010 Haiti Earthquake

    Science.gov (United States)

    Hancilar, Ufuk; Harmandar, Ebru; Çakti, Eser

    2014-05-01

    Empirical fragility functions are derived by statistical processing of the data on: i) Damaged and undamaged buildings, and ii) Ground motion intensity values at the buildings' locations. This study investigates effects of different ground motion inputs on the derived fragility functions. The previously constructed fragility curves (Hancilar et al. 2013), which rely on specific shaking intensity maps published by the USGS after the 2010 Haiti Earthquake, are compared with the fragility functions computed in the present study. Building data come from field surveys of 6,347 buildings that are grouped with respect to structural material type and number of stories. For damage assessment, the European Macroseismic Scale (EMS-98) damage grades are adopted. The simplest way to account for the variability in ground motion input could have been achieved by employing different ground motion prediction equations (GMPEs) and their standard variations. However, in this work, we prefer to rely on stochastically simulated ground motions of the Haiti earthquake. We employ five different source models available in the literature and calculate the resulting strong ground motion in time domain. In our simulations we also consider the local site effects by published studies on NEHRP site classes and micro-zoning maps of the city of Port-au-Prince. We estimate the regional distributions from the waveforms simulated at the same coordinates that we have damage information from. The estimated spatial distributions of peak ground accelerations and velocities, PGA and PGV respectively, are then used as input to fragility computations. The results show that changing the ground motion input causes significant variability in the resulting fragility functions.

  3. Path durations for use in the stochastic‐method simulation of ground motions

    Science.gov (United States)

    Boore, David M.; Thompson, Eric M.

    2014-01-01

    The stochastic method of ground‐motion simulation assumes that the energy in a target spectrum is spread over a duration DT. DT is generally decomposed into the duration due to source effects (DS) and to path effects (DP). For the most commonly used source, seismological theory directly relates DS to the source corner frequency, accounting for the magnitude scaling of DT. In contrast, DP is related to propagation effects that are more difficult to represent by analytic equations based on the physics of the process. We are primarily motivated to revisit DT because the function currently employed by many implementations of the stochastic method for active tectonic regions underpredicts observed durations, leading to an overprediction of ground motions for a given target spectrum. Further, there is some inconsistency in the literature regarding which empirical duration corresponds to DT. Thus, we begin by clarifying the relationship between empirical durations and DT as used in the first author’s implementation of the stochastic method, and then we develop a new DP relationship. The new DP function gives significantly longer durations than in the previous DP function, but the relative contribution of DP to DT still diminishes with increasing magnitude. Thus, this correction is more important for small events or subfaults of larger events modeled with the stochastic finite‐fault method.

  4. Hydrogeology and simulation of regional ground-water-level declines in Monroe County, Michigan

    Science.gov (United States)

    Reeves, Howard W.; Wright, Kirsten V.; Nicholas, J.R.

    2004-01-01

    determination of inputs and outputs of water—leakage from glacial deposits and flows across model boundaries. The imposed demands on the groundwater system create additional discharge from the bedrock aquifer, and this discharge is documented by records and estimates of water use including: residential and industrial use, irrigation, and quarry dewatering. Hydrologic characterization of Monroe County and surrounding areas was used to determine the model boundaries and inputs within the ground-water model. MODFLOW-2000 was the computer model used to simulate ground-water flow. Predevelopment, 1991, and 2001 conditions were simulated with the model. The predevelopment model did not include modern water use and was compared to information from early settlement of the county. The 1991 steady-state model included modern demands on the ground-water system and was based on a significant amount of data collected for this and previous studies. The predevelopment and 1991 simulations were used to calibrate the numerical model. The simulation of 2001 conditions was based on recent data and explored the potential ground-water levels if the current conditions persist. Model results indicate that the ground-water level will stabilize in the county near current levels if the demands imposed during 2001 are held constant.

  5. Modelling the Source of Blasting for the Numerical Simulation of Blast-Induced Ground Vibrations: A Review

    Science.gov (United States)

    Ainalis, Daniel; Kaufmann, Olivier; Tshibangu, Jean-Pierre; Verlinden, Olivier; Kouroussis, Georges

    2017-01-01

    The mining and construction industries have long been faced with considerable attention and criticism in regard to the effects of blasting. The generation of ground vibrations is one of the most significant factors associated with blasting and is becoming increasingly important as mining sites are now regularly located near urban areas. This is of concern to not only the operators of the mine but also residents. Mining sites are subjected to an inevitable compromise: a production blast is designed to fragment the utmost amount of rock possible; however, any increase in the blast can generate ground vibrations which can propagate great distances and cause structural damage or discomfort to residents in surrounding urban areas. To accurately predict the propagation of ground vibrations near these sensitive areas, the blasting process and surrounding environment must be characterised and understood. As an initial step, an accurate model of the source of blast-induced vibrations is required. This paper presents a comprehensive review of the approaches to model the blasting source in order to critically evaluate developments in the field. An overview of the blasting process and description of the various factors which influence the blast performance and subsequent ground vibrations are also presented. Several approaches to analytically model explosives are discussed. Ground vibration prediction methods focused on seed waveform and charge weight scaling techniques are presented. Finally, numerical simulations of the blasting source are discussed, including methods to estimate blasthole wall pressure time-history, and hydrodynamic codes.

  6. Hydrogeology and simulation of ground-water flow, Picatinny Arsenal and vicinity, Morris County, New Jersey

    Science.gov (United States)

    Voronin, L.M.; Rice, D.E.

    1996-01-01

    Ground-water flow in glacial sediments and bedrock at Picatinny Arsenal, N.J., was simulated by use of a three-dimensional finite-difference ground- water-flow model. The modeled area includes a 4.3-square-mile area that extends from Picatinny Lake to the Rockaway River. Most of the study area is bounded by the natural hydrologic boundaries of the ground-water system. eophysical logs, lithologic logs, particle-size data, and core data from selected wells and surface geophysical data were analyzed to define the hydrogeologic framework. Hydrogeologic sections and thickness maps define six permeable and three low-permeability layers that are represented in the model as aquifers and confining units, respectively. Hydrologic data incorporated in the model include a rate of recharge from precipitation of 22 inches per year, estimated from long-term precipitation records and estimates of evapotranspiration. Additional recharge from infiltration along valleys was estimated from measured discharge of springs along the adjacent valley walls and from estimates of runoff from upland drainage that flows to the valley floor. Horizontal and vertical hydraulic conductivities of permeable and low-permeability layers were estimated from examination of aquifer-test data, gamma-ray logs, borehole cuttings, and previously published data. Horizontal hydraulic conductivities in glacial sediments range from 10 to 380 feet per day. Vertical hydraulic conductivities of the low-permeability layers range from 0.01 to 0.7 feet per day. The model was calibrated by simulating steady-state conditions during 1989-93 and by closely matching simulated and measured ground-water levels, vertical ground-water-head differences, and streamflow gain and loss. Simulated steady-state potentiometric- surface maps produced for the six permeable layers indicate that ground water in the unconfined material within Picatinny Arsenal flows predominantly toward the center of the valley, where it discharges to Green

  7. Hydrogeology and simulation of ground-water flow at the Gettysburg Elevator Plant Superfund Site, Adams County, Pennsylvania

    Science.gov (United States)

    Low, Dennis J.; Goode, Daniel J.; Risser, Dennis W.

    2000-01-01

    Ground water in Triassic-age sedimentary fractured-rock aquifers in the area of Gettysburg, Pa., is used as drinking water and for industrial and commercial supply. In 1983, ground water at the Gettysburg Elevator Plant was found by the Pennsylvania Department of Environmental Resources to be contaminated with trichloroethene, 1,1,1-trichloroethane, and other synthetic organic compounds. As part of the U.S. Environmental Protection Agency?s Comprehensive Environmental Response, Compensation, and Liability Act, 1980 process, a Remedial Investigation was completed in July 1991, a method of site remediation was issued in the Record of Decision dated June 1992, and a Final Design Report was completed in May 1997. In cooperation with the U.S. Environmental Protection Agency in the hydrogeologic assessment of the site remediation, the U.S. Geological Survey began a study in 1997 to determine the effects of the onsite and offsite extraction wells on ground-water flow and contaminant migration from the Gettysburg Elevator Plant. This determination is based on hydrologic and geophysical data collected from 1991 to 1998 and on results of numerical model simulations of the local ground-water flow-system. The Gettysburg Elevator Site is underlain by red, green, gray, and black shales of the Heidlersburg Member of the Gettysburg Formation. Correlation of natural-gamma logs indicates the sedimentary rock strike about N. 23 degrees E. and dip about 23 degrees NW. Depth to bedrock onsite commonly is about 6 feet but offsite may be as deep as 40 feet. The ground-water system consists of two zones?a thin, shallow zone composed of soil, clay, and highly weathered bedrock and a thicker, nonweathered or fractured bedrock zone. The shallow zone overlies the bedrock zone and truncates the dipping beds parallel to land surface. Diabase dikes are barriers to ground-water flow in the bedrock zone. The ground-water system is generally confined or semi-confined, even at shallow depths. Depth

  8. Effect of ground stress on hydraulic fracturing of methane well

    Institute of Scientific and Technical Information of China (English)

    DU Chun-zhi; MAO Xian-biao; MIAO Xie-xing; WANG Peng

    2008-01-01

    Most of the coal reservoirs in China are of low-permeability, so hydraulic fracturing is widely used to improve the permeability in the extraction of gas by ground drilling. The ground stress around the well was analyzed by using theory of elasticity. The pressure when the well fractured is formulated and the effect of ground stress on pressure is discussed. The effect of ground-stress-differences on hydraulic fracturing was analyzed by using the numerical software RFPA2D-Flow in reference to the tectonic stress in Jincheng coal area. The results show that: 1) the position where initial fracture appears is random and fracture branches emerge when the fractures expand if ground stresses in any two directions within a horizontal plane are equal; 2) otherwise, the fractures expand in general along the direction of maximum ground stress and the critical pressure decreases with increasing ground-stress-differences and 3) the preferred well-disposition pattern is diamond shaped. The preferred well spacing is 250 m×300 m. This study can provide a reference for the design of wells.

  9. Negotiating the role of the professional nurse: The pedagogy of simulation: a grounded theory study.

    Science.gov (United States)

    Walton, Joni; Chute, Elizabeth; Ball, Lynda

    2011-01-01

    Simulation is the mainstay of laboratory education in health sciences, yet there is a void of pedagogy-the art and science of teaching. Nursing faculty does not have adequate evidence-based resources related to how students learn through simulation. The research questions that were addressed were as follows: (a) How do students learn using simulation? (b) What is the process of learning with simulations from the students' perspective? (c) What faculty teaching styles promote learning? and (d) How can faculty support students during simulation? Grounded theory methodology was used to explore how senior baccalaureate nursing students learn using simulation. Twenty-six students participated in this research study. Sixteen nursing students who completed two semesters of simulation courses volunteered for in-depth audio-taped interviews. In addition, there were two focus groups with five senior students in each group who validated findings and identified faculty teaching styles and supportive interventions. Negotiating the Role of the Professional Nurse was the core category, which included the following phases (I) feeling like an imposter, (II) trial and error, (III) taking it seriously, (IV) transference of skills and knowledge, and (V) professionalization. Faculty traits and teaching strategies for teaching with simulation were also identified. A conceptual model of the socialization process was developed to assist faculty in understanding the ways students learn with simulation and ways to facilitate their development. These findings provide a midrange theory for the pedagogy of simulation and will help faculty gain insight and help to assimilate into teaching-learning strategies.

  10. A detailed numerical simulation of a liquid-propellant rocket engine ground test experiment

    Science.gov (United States)

    Lankford, D. W.; Simmons, M. A.; Heikkinen, B. D.

    1992-07-01

    A computational simulation of a Liquid Rocket Engine (LRE) ground test experiment was performed using two modeling approaches. The results of the models were compared with selected data to assess the validity of state-of-the-art computational tools for predicting the flowfield and radiative transfer in complex flow environments. The data used for comparison consisted of in-band station radiation measurements obtained in the near-field portion of the plume exhaust. The test article was a subscale LRE with an afterbody, resulting in a large base region. The flight conditions were such that afterburning regions were observed in the plume flowfield. A conventional standard modeling approach underpredicted the extent of afterburning and the associated radiation levels. These results were attributed to the absence of the base flow region which is not accounted for in this model. To assess the effects of the base region a Navier-Stokes model was applied. The results of this calculation indicate that the base recirculation effects are dominant features in the immediate expansion region and resulted in a much improved comparison. However, the downstream in-band station radiation data remained underpredicted by this model.

  11. Simulated forecasts for primordial B -mode searches in ground-based experiments

    Science.gov (United States)

    Alonso, David; Dunkley, Joanna; Thorne, Ben; Næss, Sigurd

    2017-02-01

    Detecting the imprint of inflationary gravitational waves on the B -mode polarization of the cosmic microwave background (CMB) is one of the main science cases for current and next-generation CMB experiments. In this work we explore some of the challenges that ground-based facilities will have to face in order to carry out this measurement in the presence of galactic foregrounds and correlated atmospheric noise. We present forecasts for stage-3 (S3) and planned stage-4 (S4) experiments based on the analysis of simulated sky maps using a map-based Bayesian foreground-cleaning method. Our results thus consistently propagate the uncertainties on foreground parameters such as spatially varying spectral indices, as well as the bias on the measured tensor-to-scalar ratio r caused by an incorrect modeling of the foregrounds. We find that S3 and S4-like experiments should be able to put constraints on r of the order σ (r )=(0.5 - 1.0 )×10-2 and σ (r )=(0.5 - 1.0 )×10-3 respectively, assuming instrumental systematic effects are under control. We further study deviations from the fiducial foreground model, finding that, while the effects of a second polarized dust component would be minimal on both S3 and S4, a 2% polarized anomalous dust emission component would be clearly detectable by stage-4 experiments.

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

    Institute of Scientific and Technical Information of China (English)

    曹炳政; 罗奇峰

    2003-01-01

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

  13. Numerical Simulation for Roadways in Swelling Rock Under Coupling Function of Water and Ground Pressure

    Institute of Scientific and Technical Information of China (English)

    缪协兴; 卢爱红; 茅献彪; 张东升

    2002-01-01

    According to the analogical relation in the governing differential equations of the humidity stress field theory and the temperature stress field theory, the problem of solving the humidity stress field was transformed into that of solving the temperature stress field by the change of parameters. As a result, th e problem of roadways in swelling rock under the coupling function of water and ground pressure can be solved by the analytical module of temperature stress fie ld in software ANSYS. In the numerical simulation mentioned above, three kinds of supporting, I.e. Steel support, bolting support and non-support, were taken I nto account, the pressure distribution and deformation state of roadways with a swelling rock floor under the coupling function of water and ground pressure were analyzed and compared with those in the action of only ground pressure. The rese arch results provides a scientific basis for the deformation control of roadways in swelling rock.

  14. Modeling and Simulating Environmental Effects

    OpenAIRE

    Guest, Peter S.; Murphree, Tom; Frederickson, Paul A.; Guest, Arlene A.

    2012-01-01

    MOVES Research & Education Systems Seminar: Presentation; Session 4: Collaborative NWDC/NPS M&S Research; Moderator: Curtis Blais; Modeling and Simulating Environmental Effects; speakers: Peter Guest, Paul Frederickson & Tom Murphree Environmental Effects Group

  15. Near fault broadband ground motion simulation with empirical Green's functions: the Upper Rhine Graben case study

    Science.gov (United States)

    Del Gaudio, Sergio; Hok, Sébastian; Causse, Mathieu; Festa, Gaetano; Lancieri, Maria

    2016-04-01

    A fundamental stage in seismic hazard assessment is the prediction of realistic ground motion for potential future earthquakes. To do so, one of the steps is to make an estimation of the expected ground motion level and this is commonly done by the use of ground motion prediction equations (GMPEs). Nevertheless GMPEs do not represent the whole variety of source processes and this can lead to incorrect estimates for some specific case studies, such as in the near-fault range because of the lack of records of large earthquakes at short distances. In such cases, ground motion simulations can be a valid tool to complement prediction equations for scenario studies, provided that both source and propagation are accurately described and uncertainties properly addressed. Such simulations, usually referred to as "blind", require the generation of a population of ground motion records that represent the natural variability of the source process for the target earthquake scenario. In this study we performed simulations using the empirical Green's function technique, which consists in using records of small earthquakes as the medium transfer function provided the availability of small earthquakes located close to the target fault and recorded at the target site. The main advantage of this technique is that it does not require a detailed knowledge of the propagation medium, which is not always possible, but requires availability of high quality records of small earthquakes in the target area. We couple this empirical approach with a k-2 kinematic source model, which naturally let us to introduce high frequency in the source description. Here we present an application of our technique to the Upper Rhine Graben. This is an active seismic region with a moderate rate of seismicity and for which it is interesting to provide ground motion estimation in the vicinity of the faults to be compared with estimations traditionally provided by GMPEs in a seismic hazard evaluation study. We

  16. Simulation of the imaging quality of ground-based telescopes affected by atmospheric disturbances

    Science.gov (United States)

    Ren, Yubin; Kou, Songfeng; Gu, Bozhong

    2014-08-01

    Ground-based telescope imaging model is developed in this paper, the relationship between the atmospheric disturbances and the ground-based telescope image quality is studied. Simulation of the wave-front distortions caused by atmospheric turbulences has long been an important method in the study of the propagation of light through the atmosphere. The phase of the starlight wave-front is changed over time, but in an appropriate short exposure time, the atmospheric disturbances can be considered as "frozen". In accordance with Kolmogorov turbulence theory, simulating atmospheric disturbances of image model based on the phase screen distorted by atmospheric turbulences is achieved by the fast Fourier transform (FFT). Geiger mode avalanche photodiode array (APD arrays) model is used for atmospheric wave-front detection, the image is achieved by inversion method of photon counting after the target starlight goes through phase screens and ground-based telescopes. Ground-based telescope imaging model is established in this paper can accurately achieve the relationship between the quality of telescope imaging and monolayer or multilayer atmosphere disturbances, and it is great significance for the wave-front detection and optical correction in a Multi-conjugate Adaptive Optics system (MCAO).

  17. Nonstationary Stochastic Simulation of Strong Ground-Motion Time Histories : Application to the Japanese Database

    CERN Document Server

    Laurendeau, Aurore; Bonilla, Luis Fabian

    2012-01-01

    For earthquake-resistant design, engineering seismologists employ time-history analysis for nonlinear simulations. The nonstationary stochastic method previously developed by Pousse et al. (2006) has been updated. This method has the advantage of being both simple, fast and taking into account the basic concepts of seismology (Brune's source, realistic time envelope function, nonstationarity and ground-motion variability). Time-domain simulations are derived from the signal spectrogram and depend on few ground-motion parameters: Arias intensity, significant relative duration and central frequency. These indicators are obtained from empirical attenuation equations that relate them to the magnitude of the event, the source-receiver distance, and the site conditions. We improve the nonstationary stochastic method by using new functional forms (new surface rock dataset, analysis of both intra-event and inter-event residuals, consideration of the scaling relations and VS30), by assessing the central frequency with...

  18. Guide to the Revised Ground-Water Flow and Heat Transport Simulator: HYDROTHERM - Version 3

    Science.gov (United States)

    Kipp, Kenneth L.; Hsieh, Paul A.; Charlton, Scott R.

    2008-01-01

    The HYDROTHERM computer program simulates multi-phase ground-water flow and associated thermal energy transport in three dimensions. It can handle high fluid pressures, up to 1 ? 109 pascals (104 atmospheres), and high temperatures, up to 1,200 degrees Celsius. This report documents the release of Version 3, which includes various additions, modifications, and corrections that have been made to the original simulator. Primary changes to the simulator include: (1) the ability to simulate unconfined ground-water flow, (2) a precipitation-recharge boundary condition, (3) a seepage-surface boundary condition at the land surface, (4) the removal of the limitation that a specified-pressure boundary also have a specified temperature, (5) a new iterative solver for the linear equations based on a generalized minimum-residual method, (6) the ability to use time- or depth-dependent functions for permeability, (7) the conversion of the program code to Fortran 90 to employ dynamic allocation of arrays, and (8) the incorporation of a graphical user interface (GUI) for input and output. The graphical user interface has been developed for defining a simulation, running the HYDROTHERM simulator interactively, and displaying the results. The combination of the graphical user interface and the HYDROTHERM simulator forms the HYDROTHERM INTERACTIVE (HTI) program. HTI can be used for two-dimensional simulations only. New features in Version 3 of the HYDROTHERM simulator have been verified using four test problems. Three problems come from the published literature and one problem was simulated by another partially saturated flow and thermal transport simulator. The test problems include: transient partially saturated vertical infiltration, transient one-dimensional horizontal infiltration, two-dimensional steady-state drainage with a seepage surface, and two-dimensional drainage with coupled heat transport. An example application to a hypothetical stratovolcano system with unconfined

  19. Numerical simulation of strong ground motion for the Ms8.0 Wenchuan earthquake of 12 May 2008

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wei; SHEN Yang; CHEN XiaoFei

    2008-01-01

    The Wenchuan earthquake of 12 May 2008 is the most destructive earthquake in China in the past 30 years in terms of property damage and human losses. In order to understand the earthquake process and the geo-morphological factors affecting the seismic hazard, we simulated the strong ground motion caused by the earthquake, incorporating three-dimensional (3D) earth structure, finite-fault rupture,and realistic surface topography. The simulated ground motions reveal that the fault rupture and basin structure control the overall pattern of the peak ground shaking. Large peak ground velocity (PGV) is distributed in two narrow areas: one with the largest PGV values is above the hanging wall of the fault and attributed to the locations of fault asperities and rupture directivity; the other is along the northwestern margin of the Sichuan Basin and caused by both the directivity of fault rupture and the amplification in the thick sediment basin. Rough topography above the rupture fault causes wave scattering,resulting in significantly larger peak ground motion on the apex of topographic relief than in the valley.Topography and scattering also reduce the wave energy in the forward direction of fault rupture but increase the PGV in other parts of the basin. These results suggest the need for a localized hazard assessment in places of rough topography that takes the topographic effects into account. Finally, had the earthquake started at the northeast end of the fault zone and ruptured to the southwest, Chengdu would have suffered a much stronger shaking than it experienced on 12 May, 2008.

  20. Numerical simulation of strong ground motion for the M_s8.0 Wenchuan earthquake of 12 May 2008

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The Wenchuan earthquake of 12 May 2008 is the most destructive earthquake in China in the past 30 years in terms of property damage and human losses. In order to understand the earthquake process and the geo-morphological factors affecting the seismic hazard, we simulated the strong ground mo-tion caused by the earthquake, incorporating three-dimensional (3D) earth structure, finite-fault rupture, and realistic surface topography. The simulated ground motions reveal that the fault rupture and basin structure control the overall pattern of the peak ground shaking. Large peak ground velocity (PGV) is distributed in two narrow areas: one with the largest PGV values is above the hanging wall of the fault and attributed to the locations of fault asperities and rupture directivity; the other is along the north-western margin of the Sichuan Basin and caused by both the directivity of fault rupture and the ampli-fication in the thick sediment basin. Rough topography above the rupture fault causes wave scattering, resulting in significantly larger peak ground motion on the apex of topographic relief than in the valley. Topography and scattering also reduce the wave energy in the forward direction of fault rupture but increase the PGV in other parts of the basin. These results suggest the need for a localized hazard as-sessment in places of rough topography that takes the topographic effects into account. Finally, had the earthquake started at the northeast end of the fault zone and ruptured to the southwest, Chengdu would have suffered a much stronger shaking than it experienced on 12 May, 2008.

  1. Accuracy of three-dimensional seismic ground response analysis in time domain using nonlinear numerical simulations

    Science.gov (United States)

    Liang, Fayun; Chen, Haibing; Huang, Maosong

    2017-07-01

    To provide appropriate uses of nonlinear ground response analysis for engineering practice, a three-dimensional soil column with a distributed mass system and a time domain numerical analysis were implemented on the OpenSees simulation platform. The standard mesh of a three-dimensional soil column was suggested to be satisfied with the specified maximum frequency. The layered soil column was divided into multiple sub-soils with a different viscous damping matrix according to the shear velocities as the soil properties were significantly different. It was necessary to use a combination of other one-dimensional or three-dimensional nonlinear seismic ground analysis programs to confirm the applicability of nonlinear seismic ground motion response analysis procedures in soft soil or for strong earthquakes. The accuracy of the three-dimensional soil column finite element method was verified by dynamic centrifuge model testing under different peak accelerations of the earthquake. As a result, nonlinear seismic ground motion response analysis procedures were improved in this study. The accuracy and efficiency of the three-dimensional seismic ground response analysis can be adapted to the requirements of engineering practice.

  2. Simulation of lightning attachment to open ground, tall towers and aircraft

    Energy Technology Data Exchange (ETDEWEB)

    Ratnamahilan, P.; Hoole, P. (Univ. of Technology, Lae (Papua New Guinea). Dept. of Electrical and Telecommunications Engineering); Ratnajeevan, S.; Hoole, H. (Harvey Mudd College, Claremont, CA (United States). Dept. of Engineering)

    1993-04-01

    The characteristics of lightning waveforms are important in taking protective measures against it. However, many of these characteristics cannot be measured. This paper employs a mathematical model of lightning currents to write a software package to simulate all manner of lightning flashes. The capabilities available to us through this are demonstrated by extracting the behavior of lightning waveforms following attachment to open ground, tall towers and aircraft.

  3. SuReSim: simulating localization microscopy experiments from ground truth models.

    Science.gov (United States)

    Venkataramani, Varun; Herrmannsdörfer, Frank; Heilemann, Mike; Kuner, Thomas

    2016-04-01

    Super-resolution fluorescence microscopy has become a widely used tool in many areas of research. However, designing and validating super-resolution experiments to address a research question in a technically feasible and scientifically rigorous manner remains a fundamental challenge. We developed SuReSim, a software tool that simulates localization data of arbitrary three-dimensional structures represented by ground truth models, allowing users to systematically explore how changing experimental parameters can affect potential imaging outcomes.

  4. Ground-simulation investigations of VTOL airworthiness criteria for terminal-area operations

    Science.gov (United States)

    Lebacqz, J. V.; Decker, W. A.; Alderete, T. S.; Scott, B. C.; Harper, P. J. G.; Chung, W. W.

    1990-01-01

    Several ground-based simulation experiments undertaken to investigate concerns related to tilt-rotor aircraft airworthiness were conducted. The experiments were conducted on the National Aeronautics and Space Administration (NASA) Ames Research Center's Vertical Motion Simulator, which permits simulation of a wide variety of aircraft with a high degree of fidelity of motion cueing. Variations in conversion/deceleration profile, type of augmentation or automation, level of display assistance, and meteorological conditions were considered in the course of the experiments. Certification pilots from the Federal Aviation Administration (FAA) and the Civil Aviation Authority (CAA) participated, in addition to NASA research pilots. The setup of these experiments on the simulator is summarized, and some of the results highlighted.

  5. Numerical implementation of Voigt and Maxwell models for simulation of waves in the ground

    Directory of Open Access Journals (Sweden)

    Sheshenin Sergey Vladimirovich

    2014-12-01

    Full Text Available A lot of papers have been dedicated to simulation of dynamic processes in soil and underground structures. For example, some authors considered wave distribution in underground water pipes for creation of vibration monitoring system, others considered theoretical and algorithm aspects of efficient implementation of realistic seismic wave attenuation due to viscosity development with the help of Finite Difference Method, etc. The paper describes the numerical simulation, designed for simulation of the stress-strain state in the ground subjected to wave processes. We consider the ground with a concrete structure immersed in. The purpose of the work is the description of small vibrations in hard soil, which can nevertheless make undesirable impact on the objects in the ground or on the surface. Explicit Wilkins type scheme is used for time integration. It has proven to be successful, including the use in a well-known LS-DYNA code. As a result we created our own computer code based on the finite element method (FEM. An example of its practical usage is given.

  6. Numerical Study of a Long-Lived, Isolated Wake Vortex in Ground Effect

    Science.gov (United States)

    Proctor, Fred H.

    2014-01-01

    This paper examines a case observed during the 1990 Idaho Falls Test program, in which a wake vortex having an unusually long lifetime was observed while in ground effect. A numerical simulation is performed with a Large Eddy Simulation model to understand the response of the environment in affecting this event. In the simulation, it was found that one of the vortices decayed quickly, with the remaining vortex persisting beyond the time-bound of typical vortex lifetimes. This unusual behavior was found to be related to the first and second vertical derivatives of the ambient crosswind.

  7. Hydrogeology and simulation of ground-water flow at Arnold Air Force Base, Coffee and Franklin counties, Tennessee

    Science.gov (United States)

    Haugh, C.J.; Mahoney, E.N.

    1994-01-01

    The U.S. Air Force at Arnold Air Force Base (AAFB), in Coffee and Franklin Counties, Tennessee, is investigating ground-water contamination in selected areas of the base. This report documents the results of a comprehensive investigation of the regional hydrogeology of the AAFB area. Three aquifers within the Highland Rim aquifer system, the shallow aquifer, the Manchester aquifer, and the Fort Payne aquifer, have been identified in the study area. Of these, the Manchester aquifer is the primary source of water for domestic use. Drilling and water- quality data indicate that the Chattanooga Shale is an effective confining unit, isolating the Highland Rim aquifer system from the deeper, upper Central Basin aquifer system. A regional ground-water divide, approximately coinciding with the Duck River-Elk River drainage divide, underlies AAFB and runs from southwest to northeast. The general direction of most ground-water flow is to the north- west or to the northwest or to the southeast from the divide towards tributary streams that drain the area. Recharge estimates range from 4 to 11 inches per year. Digital computer modeling was used to simulate and provide a better understanding of the ground-water flow system. The model indicates that most of the ground-water flow occurs in the shallow and Manchester aquifers. The model was most sensitive to increases in hydraulic conductivity and changes in recharge rates. Particle-tracking analysis from selected sites of ground-water contamination indicates a potential for contami- nants to be transported beyond the boundary of AAFB.

  8. The Ground Flash Fraction Retrieval Algorithm Employing Differential Evolution: Simulations and Applications

    Science.gov (United States)

    Koshak, William; Solakiewicz, Richard

    2012-01-01

    The ability to estimate the fraction of ground flashes in a set of flashes observed by a satellite lightning imager, such as the future GOES-R Geostationary Lightning Mapper (GLM), would likely improve operational and scientific applications (e.g., severe weather warnings, lightning nitrogen oxides studies, and global electric circuit analyses). A Bayesian inversion method, called the Ground Flash Fraction Retrieval Algorithm (GoFFRA), was recently developed for estimating the ground flash fraction. The method uses a constrained mixed exponential distribution model to describe a particular lightning optical measurement called the Maximum Group Area (MGA). To obtain the optimum model parameters (one of which is the desired ground flash fraction), a scalar function must be minimized. This minimization is difficult because of two problems: (1) Label Switching (LS), and (2) Parameter Identity Theft (PIT). The LS problem is well known in the literature on mixed exponential distributions, and the PIT problem was discovered in this study. Each problem occurs when one allows the numerical minimizer to freely roam through the parameter search space; this allows certain solution parameters to interchange roles which leads to fundamental ambiguities, and solution error. A major accomplishment of this study is that we have employed a state-of-the-art genetic-based global optimization algorithm called Differential Evolution (DE) that constrains the parameter search in such a way as to remove both the LS and PIT problems. To test the performance of the GoFFRA when DE is employed, we applied it to analyze simulated MGA datasets that we generated from known mixed exponential distributions. Moreover, we evaluated the GoFFRA/DE method by applying it to analyze actual MGAs derived from low-Earth orbiting lightning imaging sensor data; the actual MGA data were classified as either ground or cloud flash MGAs using National Lightning Detection Network[TM] (NLDN) data. Solution error

  9. Critical Evaluation of the ISCCP Simulator Using Ground-Based Remote Sensing Data

    Energy Technology Data Exchange (ETDEWEB)

    Mace, G G; Houser, S; Benson, S; Klein, S A; Min, Q

    2009-11-02

    Given the known shortcomings in representing clouds in Global Climate Models (GCM) comparisons with observations are critical. The International Satellite Cloud Climatology Project (ISCCP) diagnostic products provide global descriptions of cloud top pressure and column optical depth that extends over multiple decades. The necessary limitations of the ISCCP retrieval algorithm require that before comparisons can be made between model output and ISCCP results the model output must be modified to simulate what ISCCP would diagnose under the simulated circumstances. We evaluate one component of the so-called ISCCP simulator in this study by comparing ISCCP and a similar algorithm with various long-term statistics derived from the Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) Climate Research Facility ground-based remote sensors. We find that were a model to simulate the cloud radiative profile with the same accuracy as can be derived from the ARM data, then the likelihood of that occurrence being placed in the same cloud top pressure and optical depth bin as ISCCP of the 9 bins that have become standard ranges from 30% to 70% depending on optical depth. While the ISCCP simulator improved the agreement of cloud-top pressure between ground-based remote sensors and satellite observations, we find minor discrepancies due to the parameterization of cloud top pressure in the ISCCP simulator. The primary source of error seems to be related to discrepancies in visible optical depth that are not accounted for in the ISCCP simulator. We show that the optical depth discrepancies are largest when the assumptions necessary for plane parallel radiative transfer optical depths retrievals are violated.

  10. Issues for Simulation of Galactic Cosmic Ray Exposures for Radiobiological Research at Ground Based Accelerators

    Directory of Open Access Journals (Sweden)

    Myung-Hee Y Kim

    2015-06-01

    Full Text Available For research on the health risks of galactic cosmic rays (GCR ground-based accelerators have been used for radiobiology research with mono-energetic beams of single high charge, Z and energy, E (HZE particles. In this paper we consider the pros and cons of a GCR reference field at a particle accelerator. At the NASA Space Radiation Laboratory (NSRL we have proposed a GCR simulator, which implements a new rapid switching mode and higher energy beam extraction to 1.5 GeV/u, in order to integrate multiple ions into a single simulation within hours or longer for chronic exposures. After considering the GCR environment and energy limitations of NSRL, we performed extensive simulation studies using the stochastic transport code, GERMcode (GCR Event Risk Model to define a GCR reference field using 9 HZE particle beam-energy combinations each with a unique absorber thickness to provide fragmentation and 10 or more energies of proton and 4He beams. The reference field is shown to well represent the charge dependence of GCR dose in several energy bins behind shielding compared to a simulated GCR environment. However a more significant challenge for space radiobiology research is to consider chronic GCR exposure of up to 3 years in relation to simulations with animal models of human risks. We discuss issues in approaches to map important biological time scales in experimental models using ground-based simulation with extended exposure of up to a few weeks using chronic or fractionation exposures. A kinetics model of HZE particle hit probabilities suggests that experimental simulations of several weeks will be needed to avoid high fluence rate artifacts, which places limitations on the experiments to be performed. Ultimately risk estimates are limited by theoretical understanding, and focus on improving understanding of mechanisms and development of experimental models to improve this understanding should remain the highest priority for space radiobiology

  11. Multipollutant health effect simulations

    Data.gov (United States)

    U.S. Environmental Protection Agency — Resulting betas (health effects) from a variety of copollutant epidemiologic models used to analyze the impact of exposure measurement error on health effect...

  12. Simulation of ground-water flow and solute transport in the Glen Canyon aquifer, East-Central Utah

    Science.gov (United States)

    Freethey, Geoffrey W.; Stolp, Bernard J.

    2010-01-01

    The extraction of methane from coal beds in the Ferron coal trend in central Utah started in the mid-1980s. Beginning in 1994, water from the extraction process was pressure injected into the Glen Canyon aquifer. The lateral extent of the aquifer that could be affected by injection is about 7,600 square miles. To address regional-scale effects of injection over a decadal time frame, a conceptual model of ground-water movement and transport of dissolved solids was formulated. A numerical model that incorporates aquifer concepts was then constructed and used to simulate injection. The Glen Canyon aquifer within the study area is conceptualized in two parts-an active area of ground-water flow and solute transport that exists between recharge areas in the San Rafael Swell and Desert, Waterpocket Fold, and Henry Mountains and discharge locations along the Muddy, Dirty Devil, San Rafael, and Green Rivers. An area of little or negligible ground-water flow exists north of Price, Utah, and beneath the Wasatch Plateau. Pressurized injection of coal-bed methane production water occurs in this area where dissolved-solids concentrations can be more than 100,000 milligrams per liter. Injection has the potential to increase hydrologic interaction with the active flow area, where dissolved-solids concentrations are generally less than 3,000 milligrams per liter. Pressurized injection of coal-bed methane production water in 1994 initiated a net addition of flow and mass of solutes into the Glen Canyon aquifer. To better understand the regional scale hydrologic interaction between the two areas of the Glen Canyon aquifer, pressurized injection was numerically simulated. Data constraints precluded development of a fully calibrated simulation; instead, an uncalibrated model was constructed that is a plausible representation of the conceptual flow and solute-transport processes. The amount of injected water over the 36-year simulation period is about 25,000 acre-feet. As a result

  13. Synthetic seismograms of ground motion near earthquake fault using simulated Green's function method

    Institute of Scientific and Technical Information of China (English)

    ZHAO Zhixin; ZHAO Zhao; XU Jiren; Ryuji Kubota

    2006-01-01

    Seismograms near source fault were synthesized using the hybrid empirical Green's function method where he discretely simulated seismic waveforms are used for Green's functions instead of the observed waveforms of small earthquakes. The Green's function seismic waveforms for small earthquake were calculated by solving wave equation using the pseudo-spectral method with the staggered grid real FFT strategy under a detailed 2-D velocity structure in Kobe region. Magnitude and seismic moment of simulated Green's function waveforms were firstly determined by using the relationship between fault length and corner frequency of source spectrum. The simulated Green's function waveforms were employed to synthesize seismograms of strong ground motion near the earthquake fault. The synthetic seismograms of the target earthquake were performed based on the model with multiple source rupture processes. The results suggest that synthesized seismograms coincide well with observed seismic waveforms of the 1995 Hyogo-ken Nanbu earthquake. The simulated Green's function method is very useful for prediction of the strong ground motion in region without observed seismic waveforms.The present technique spreads application field of the empirical Green's function method.

  14. Simulated ground motion in Santa Clara Valley, California, and vicinity from M≥6.7 scenario earthquakes

    Science.gov (United States)

    Harmsen, Stephen C.; Hartzell, Stephen

    2008-01-01

    Models of the Santa Clara Valley (SCV) 3D velocity structure and 3D finite-difference software are used to predict ground motions from scenario earthquakes on the San Andreas (SAF), Monte Vista/Shannon, South Hayward, and Calaveras faults. Twenty different scenario ruptures are considered that explore different source models with alternative hypocenters, fault dimensions, and rupture velocities and three different velocity models. Ground motion from the full wave field up to 1 Hz is exhibited as maps of peak horizontal velocity and pseudospectral acceleration at periods of 1, 3, and 5 sec. Basin edge effects and amplification in sedimentary basins of the SCV are observed that exhibit effects from shallow sediments with relatively low shear-wave velocity (330 m/sec). Scenario earthquakes have been simulated for events with the following magnitudes: (1) M 6.8–7.4 Calaveras sources, (2) M 6.7–6.9 South Hayward sources, (3) M 6.7 Monte Vista/Shannon sources, and (4) M 7.1–7.2 Peninsula segment of the SAF sources. Ground motions are strongly influenced by source parameters such as rupture velocity, rise time, maximum depth of rupture, hypocenter, and source directivity. Cenozoic basins also exert a strong influence on ground motion. For example, the Evergreen Basin on the northeastern side of the SCV is especially responsive to 3–5-sec energy from most scenario earthquakes. The Cupertino Basin on the southwestern edge of the SCV tends to be highly excited by many Peninsula and Monte Vista fault scenarios. Sites over the interior of the Evergreen Basin can have long-duration coda that reflect the trapping of seismic energy within this basin. Plausible scenarios produce predominantly 5-sec wave trains with greater than 30 cm/sec sustained ground-motion amplitude with greater than 30 sec duration within the Evergreen Basin.

  15. Inferring Average Ground Profiles of the Muon Density of Inclined Air Showers from Monte-Carlo Simulations at Ultra-High Energy

    CERN Document Server

    Dembinski, Hans; Deligny, Olivier; Hebbeker, Thomas

    2009-01-01

    A standard method to measure ultra-high energy cosmic rays is the sampling of the ground particle profile of the extensive air shower that is produced in the atmosphere with an array of surface detectors. The primary energy of inclined air showers with zenith angles >60 Deg can be reconstructed by using simulated 2-D profiles of the ground density of muons. We will present an effective way to extract such profiles from a library of Monte-Carlo simulated air showers. Also, we will demonstrate a way to speed up the simulation of ground profiles of the muon density in very inclined showers by three orders of magnitude, if only the muon component in the shower is of interest.

  16. Developing a grounded theory for interprofessional collaboration acquisition using facilitator and actor perspectives in simulated wilderness medical emergencies.

    Science.gov (United States)

    Smith, Heather A; Reade, Maurianne; Marr, Marion; Jeeves, Nicholas

    2017-01-01

    Interprofessional collaboration is a complex process that has the potential to transform patient care for the better in urban, rural and remote healthcare settings. Simulation has been found to improve participants' interprofessional competencies, but the mechanisms by which interprofessionalism is learned have yet to be understood. A rural wilderness medicine conference (WildER Med) in northern Ontario, Canada with simulated medical scenarios has been demonstrated to be effective in improving participants' collaboration without formal interprofessional education (IPE) curriculum. Interprofessionalism may be taught through rural and remote medical simulation, as done in WildER Med where participants' interprofessional competencies improved without any formal IPE curriculum. This learning may be attributed to the informal and hidden curriculum. Understanding the mechanism by which this rural educational experience contributed to participants' learning to collaborate requires insight into the events before, during and after the simulations. The authors drew upon feedback from facilitators and patient actors in one-on-one interviews to develop a grounded theory for how collaboration is taught and learned. Sharing emerged as the core concept of a grounded theory to explain how team members acquired interprofessional collaboration competencies. Sharing was enacted through the strategies of developing common goals, sharing leadership, and developing mutual respect and understanding. Further analysis of the data and literature suggests that the social wilderness environment was foundational in enabling sharing to occur. Medical simulations in other rural and remote settings may offer an environment conducive to collaboration and be effective in teaching collaboration. When designing interprofessional education, health educators should consider using emergency response teams or rural community health teams to optimize the informal and hidden curriculum contributing to

  17. Ground Simulation of an Autonomous Satellite Rendezvous and Tracking System Using Dual Robotic Systems

    Science.gov (United States)

    Trube, Matthew J.; Hyslop, Andrew M.; Carignan, Craig R.; Easley, Joseph W.

    2012-01-01

    A hardware-in-the-loop ground system was developed for simulating a robotic servicer spacecraft tracking a target satellite at short range. A relative navigation sensor package "Argon" is mounted on the end-effector of a Fanuc 430 manipulator, which functions as the base platform of the robotic spacecraft servicer. Machine vision algorithms estimate the pose of the target spacecraft, mounted on a Rotopod R-2000 platform, relay the solution to a simulation of the servicer spacecraft running in "Freespace", which performs guidance, navigation and control functions, integrates dynamics, and issues motion commands to a Fanuc platform controller so that it tracks the simulated servicer spacecraft. Results will be reviewed for several satellite motion scenarios at different ranges. Key words: robotics, satellite, servicing, guidance, navigation, tracking, control, docking.

  18. Numerical Simulations of Blast Loads from Near-Field Ground Explosions in Air

    Science.gov (United States)

    Dobrociński, Stanisław; Flis, Leszek

    2015-12-01

    Numerical simulations of air blast loading in the near-field acting on the ground have been performed. A simplified blast model based on empirical blast loading data representing spherical and hemispherical explosive shapes has been simulated. Conwep is an implementation of the empirical blast models presented by Kingery and Bulmash, which is also implemented in the commercial code LS-DYNA based on work done by Rahnders-Pehrson and Bannister. This makes it possible to simulate blast loads acting on structures representing spherical and hemispherical explosive shapes of TNT with reasonable computational effort as an alternative to the SPH and Eulerian model. The CPU time for the simplified blast model is however considerably shorter and may still be useful in time consuming concept studies. Reasonable numerical results using reasonable model sizes can be achieved not only for modelling near-field explosions in air but most areas of geotechnical. Calculation was compared with blast SPH and Eulerian model.

  19. Finite difference time domain method forward simulation of complex geoelectricity ground penetrating radar model

    Institute of Scientific and Technical Information of China (English)

    DAI Qian-wei; FENG De-shan; HE Ji-shan

    2005-01-01

    The ground penetrating radar(GPR) forward simulation all aims at the singular and regular models, such as sandwich model, round cavity, square cavity, and so on, which are comparably simple. But as to the forward of curl interface underground or "v" figure complex model, it is difficult to realize. So it is important to forward the complex geoelectricity model. This paper takes two Maxwell's vorticity equations as departure point, makes use of the principles of Yee's space grid model theory and the basic principle finite difference time domain method, and deduces a GPR forward system of equation of two dimensional spaces. The Mur super absorbed boundary condition is adopted to solve the super strong reflection on the interceptive boundary when there is the forward simulation. And a self-made program is used to process forward simulation to two typical geoelectricity model.

  20. Crevice Repassivation Potentials for Alloy 22 in Simulated Concentrated Ground Waters

    Energy Technology Data Exchange (ETDEWEB)

    Rebak, R B; Evans, K J; Ilevbare, G O

    2006-11-08

    The resistance of Alloy 22 (N06022) to localized corrosion, mainly crevice corrosion, has been extensively investigated in the last few years. However, the behavior of Alloy 22 in concentrated aqueous solutions that may simulate concentrated ground waters was not fully understood. Systematic electrochemical tests using cyclic potentiodynamic polarization as well as the Tsujikawa-Hisamatsu electrochemical method were performed to determine the crevice corrosion susceptibility of Alloy 22 in simulated concentrated water (SCW), simulated acidified water (SAW) and basic saturated water (BSW). Results show that Alloy 22 is immune to crevice corrosion in SCW and SAW but may suffer crevice corrosion initiation in BSW. Results also show that in a naturally aerated environment, the corrosion potential would never reach the critical potential for crevice corrosion initiation.

  1. Numerical Simulations of Blast Loads from Near-Field Ground Explosions in Air

    Directory of Open Access Journals (Sweden)

    Dobrociński Stanisław

    2015-12-01

    Full Text Available Numerical simulations of air blast loading in the near-field acting on the ground have been performed. A simplified blast model based on empirical blast loading data representing spherical and hemispherical explosive shapes has been simulated. Conwep is an implementation of the empirical blast models presented by Kingery and Bulmash, which is also implemented in the commercial code LS-DYNA based on work done by Rahnders-Pehrson and Bannister. This makes it possible to simulate blast loads acting on structures representing spherical and hemispherical explosive shapes of TNT with reasonable computational effort as an alternative to the SPH and Eulerian model. The CPU time for the simplified blast model is however considerably shorter and may still be useful in time consuming concept studies. Reasonable numerical results using reasonable model sizes can be achieved not only for modelling near-field explosions in air but most areas of geotechnical. Calculation was compared with blast SPH and Eulerian model.

  2. Simulation of embedded heat exchangers of solar aided ground source heat pump system

    Institute of Scientific and Technical Information of China (English)

    王芳; 郑茂余; 邵俊鹏; 李忠建

    2008-01-01

    Aimed at unbalance of soil temperature field of ground source heat pump system, solar aided energy storage system was established. In solar assisted ground-source heat pump (SAGSHP) system with soil storage, solar energy collected in three seasons was stored in the soil by vertical U type soil exchangers. The heat abstracted by the ground-source heat pump and collected by the solar collector was employed to heating. Some of the soil heat exchangers were used to store solar energy in the soil so as to be used in next winter after this heating period; and the others were used to extract cooling energy directly in the soil by circulation pump for air conditioning in summer. After that solar energy began to be stored in the soil and ended before heating period. Three dimensional dynamic numerical simulations were built for soil and soil heat exchanger through finite element method. Simulation was done in different strata month by month. Variation and restoration of soil temperature were studied. Economy and reliability of long term SAGSHP system were revealed. It can be seen that soil temperature is about 3 ℃ higher than the original one after one year’s running. It is beneficial for the system to operate for long period.

  3. Experimental Investigation of Rotorcraft Outwash in Ground Effect

    Science.gov (United States)

    Tanner, Philip E.; Overmeyer, Austin D.; Jenkins, Luther N.; Yao, Chung-Sheng; Bartram, Scott M.

    2015-01-01

    The wake characteristics of a rotorcraft are affected by the proximity of a rotor to the ground surface, especially during hover. Ground effect is encountered when the rotor disk is within a distance of a few rotor radii above the ground surface and results in an increase in thrust for a given power relative to that same power condition with the rotor out of ground effect. Although this phenomenon has been highly documented and observed since the beginning of the helicopter age, there is still a relatively little amount of flow-field data existing to help understand its features. Joint Army and NASA testing was conducted at NASA Langley Research Center using a powered rotorcraft model in hover at various rotor heights and thrust conditions in order to contribute to the complete outwash data set. The measured data included outwash velocities and directions, rotor loads, fuselage loads, and ground pressures. The researchers observed a linear relationship between rotor height and percent download on the fuselage, peak mean outwash velocities occurring at radial stations between 1.7 and 1.8 r/R regardless of rotor height, and the measurement azimuthal dependence of the outwash profile for a model incorporating a fuselage. Comparisons to phase-locked PIV data showed similar contours but a more contracted wake boundary for the PIV data. This paper describes the test setup and presents some of the averaged results.

  4. Effect of vehicle front end profiles leading to pedestrian secondary head impact to ground.

    Science.gov (United States)

    Gupta, Vishal; Yang, King H

    2013-11-01

    Most studies of pedestrian injuries focus on reducing traumatic injuries due to the primary impact between the vehicle and the pedestrian. However, based on the Pedestrian Crash Data Study (PCDS), some researchers concluded that one of the leading causes of head injury for pedestrian crashes can be attributed to the secondary impact, defined as the impact of the pedestrian with the ground after the primary impact of the pedestrian with the vehicle. The purpose of this study is to understand if different vehicle front-end profiles can affect the risk of pedestrian secondary head impact with the ground and thus help in reducing the risk of head injury during secondary head impact with ground. Pedestrian responses were studied using several front-end profiles based off a mid-size vehicle and a SUV that have been validated previously along with several MADYMO pedestrian models. Mesh morphing is used to explore changes to the bumper height, bonnet leading-edge height, and bonnet rear reference-line height. Simulations leading up to pedestrian secondary impact with ground are conducted at impact speeds of 40 and 30 km/h. In addition, three pedestrian sizes (50th, 5th and 6yr old child) are used to enable us to search for a front-end profile that performs well for multiple sizes of pedestrians, not just one particular size. In most of the simulations, secondary ground impact with pedestrian head/neck/shoulder region occurred. However, there were some front-end profiles that promoted secondary ground impact with pedestrian lower extremities, thus avoiding pedestrian secondary head impact with ground. Previous pedestrian safety research work has suggested the use of active safety methods, such as 'pop up hood', to reduce pedestrian head injury during primary impact. Accordingly, we also conducted simulations using a model with the hood raised to capture the effect of a pop-up hood. These simulations indicated that even though pop-up hood helped reducing the head injury

  5. Three-Dimensional Finite Difference Simulation of Ground Motions from the August 24, 2014 South Napa Earthquake

    Energy Technology Data Exchange (ETDEWEB)

    Rodgers, Arthur J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Univ. of California, Berkeley, CA (United States); Dreger, Douglas S. [Univ. of California, Berkeley, CA (United States); Pitarka, Arben [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-06-15

    We performed three-dimensional (3D) anelastic ground motion simulations of the South Napa earthquake to investigate the performance of different finite rupture models and the effects of 3D structure on the observed wavefield. We considered rupture models reported by Dreger et al. (2015), Ji et al., (2015), Wei et al. (2015) and Melgar et al. (2015). We used the SW4 anelastic finite difference code developed at Lawrence Livermore National Laboratory (Petersson and Sjogreen, 2013) and distributed by the Computational Infrastructure for Geodynamics. This code can compute the seismic response for fully 3D sub-surface models, including surface topography and linear anelasticity. We use the 3D geologic/seismic model of the San Francisco Bay Area developed by the United States Geological Survey (Aagaard et al., 2008, 2010). Evaluation of earlier versions of this model indicated that the structure can reproduce main features of observed waveforms from moderate earthquakes (Rodgers et al., 2008; Kim et al., 2010). Simulations were performed for a domain covering local distances (< 25 km) and resolution providing simulated ground motions valid to 1 Hz.

  6. Hybrid Simulations of the Broadband Ground Motions for the 2008 MS8.0 Wenchuan, China, Earthquake

    Science.gov (United States)

    Yu, X.; Zhang, W.

    2012-12-01

    The Ms8.0 Wenchuan earthquake occurred on 12 May 2008 at 14:28 Beijing Time. It is the largest event happened in the mainland of China since the 1976, Mw7.6, Tangshan earthquake. Due to occur in the mountainous area, this great earthquake and the following thousands aftershocks also caused many other geological disasters, such as landslide, mud-rock flow and "quake lakes" which formed by landslide-induced reservoirs. These resulted in tremendous losses of life and property. Casualties numbered more than 80,000 people, and there were major economic losses. However, this earthquake is the first Ms 8 intraplate earthquake with good close fault strong motion coverage. Over four hundred strong motion stations of the National Strong Motion Observation Network System (NSMONS) recorded the mainshock. Twelve of them located within 20 km of the fault traces and another 33 stations located within 100 km. These observations, accompanying with the hundreds of GPS vectors and multiple ALOS INSAR images, provide an unprecedented opportunity to study the rupture process of such a great intraplate earthquake. In this study, we calculate broadband near-field ground motion synthetic waveforms of this great earthquake using a hybrid broadband ground-motion simulation methodology, which combines a deterministic approach at low frequencies (f Green's function calculation approach at high frequency ( ~ 10.0 Hz). The fault rupture is represented kinematically and incorporates spatial heterogeneity in slip, rupture speed, and rise time that were obtained by an inversion kinematic source model. At the same time, based on the aftershock data, we analyze the site effects for the near-field stations. Frequency-dependent site-amplification values for each station are calculated using genetic algorithms. For the calculation of the synthetic waveforms, at first, we carry out simulations using the hybrid methodology for the frequency up to 10.0 Hz. Then, we consider for the soil site simulations

  7. Large eddy simulation of flows around ground vehicles and other bluff bodies.

    Science.gov (United States)

    Krajnovic, Sinisa

    2009-07-28

    A brief review of large eddy simulation (LES) applications for different bluff-body flows performed by the author and his co-workers is presented. Examples of flows range from simple cube flows characterized by sharp edge separation over a three-dimensional hill where LES relies on good near-wall resolution, to complex flows of a tall, finite cylinder that contains several flow regimes that cause different challenges to LES. The second part of the paper is devoted to flows around ground vehicles at moderate Reynolds numbers. Although the present review proves the applicability of LES for various bluff-body flows, an increase of the Reynolds number towards the operational speeds of ground vehicles requires accurate near-wall modelling for a successful LES.

  8. Variability of the Martian thermosphere during eight Martian years as simulated by a ground-to-exosphere global circulation model

    Science.gov (United States)

    González-Galindo, F.; López-Valverde, M. A.; Forget, F.; García-Comas, M.; Millour, E.; Montabone, L.

    2015-11-01

    Using a ground-to-exosphere general circulation model for Mars we have simulated the variability of the dayside temperatures at the exobase during eight Martian years (MY, from MY24 to MY31, approximately from 1998 to 2013), taking into account the observed day-to-day solar and dust load variability. We show that the simulated temperatures are in good agreement with the exospheric temperatures derived from Precise Orbit Determination of Mars Global Surveyor. We then study the effects of the solar variability and of two planetary-encircling dust storms on the simulated temperatures. The seasonal effect produced by the large eccentricity of the Martian orbit translates in an aphelion-to-perihelion temperature contrast in every simulated year. However, the magnitude of this seasonal temperature variation is strongly affected by the solar conditions, ranging from 50 K for years corresponding to solar minimum conditions to almost 140 K during the last solar maximum. The 27 day solar rotation cycle is observed on the simulated temperatures at the exobase, with average amplitude of the temperature oscillation of 2.6 K but with a significant interannual variability. These two results highlight the importance of taking into account the solar variability when simulating the Martian upper atmosphere and likely have important implications concerning the atmospheric escape rate. We also show that the global dust storms in MY25 and MY28 have a significant effect on the simulated temperatures. In general, they increase the exospheric temperatures over the low latitude and midlatitude regions and decrease them in the polar regions.

  9. Aerodynamic ground effect in fruitfly sized insect takeoff

    CERN Document Server

    Kolomenskiy, Dmitry; Engels, Thomas; Liu, Hao; Schneider, Kai; Nave, Jean-Christophe

    2015-01-01

    Flapping-wing takeoff is studied using numerical modelling, considering the voluntary takeoff of a fruitfly as reference. The parameters of the model are then varied to explore the possible effects of interaction between the flapping-wing model and the ground plane. The numerical method is based on a three-dimensional Navier-Stokes solver and a simple flight dynamics solver that accounts for the body weight, inertia, and the leg thrust. Forces, power and displacements are compared for takeoffs with and without ground effect. Natural voluntary takeoff of a fruitfly, modified takeoffs and hovering are analyzed. The results show that the ground effect during the natural voluntary takeoff is negligible. In the modified takeoffs, the ground effect does not produce any significant increase of the vertical force neither. Moreover, the vertical force even drops in most of the cases considered. There is a consistent increase of the horizontal force, and a decrease of the aerodynamic power, if the rate of climb is suff...

  10. Aerodynamic Ground Effect in Fruitfly Sized Insect Takeoff.

    Directory of Open Access Journals (Sweden)

    Dmitry Kolomenskiy

    Full Text Available Aerodynamic ground effect in flapping-wing insect flight is of importance to comparative morphologies and of interest to the micro-air-vehicle (MAV community. Recent studies, however, show apparently contradictory results of either some significant extra lift or power savings, or zero ground effect. Here we present a numerical study of fruitfly sized insect takeoff with a specific focus on the significance of leg thrust and wing kinematics. Flapping-wing takeoff is studied using numerical modelling and high performance computing. The aerodynamic forces are calculated using a three-dimensional Navier-Stokes solver based on a pseudo-spectral method with volume penalization. It is coupled with a flight dynamics solver that accounts for the body weight, inertia and the leg thrust, while only having two degrees of freedom: the vertical and the longitudinal horizontal displacement. The natural voluntary takeoff of a fruitfly is considered as reference. The parameters of the model are then varied to explore possible effects of interaction between the flapping-wing model and the ground plane. These modified takeoffs include cases with decreased leg thrust parameter, and/or with periodic wing kinematics, constant body pitch angle. The results show that the ground effect during natural voluntary takeoff is negligible. In the modified takeoffs, when the rate of climb is slow, the difference in the aerodynamic forces due to the interaction with the ground is up to 6%. Surprisingly, depending on the kinematics, the difference is either positive or negative, in contrast to the intuition based on the helicopter theory, which suggests positive excess lift. This effect is attributed to unsteady wing-wake interactions. A similar effect is found during hovering.

  11. A Coupled Multiphysics Approach for Simulating Induced Seismicity, Ground Acceleration and Structural Damage

    Science.gov (United States)

    Podgorney, Robert; Coleman, Justin; Wilkins, Amdrew; Huang, Hai; Veeraraghavan, Swetha; Xia, Yidong; Permann, Cody

    2017-04-01

    Numerical modeling has played an important role in understanding the behavior of coupled subsurface thermal-hydro-mechanical (THM) processes associated with a number of energy and environmental applications since as early as the 1970s. While the ability to rigorously describe all key tightly coupled controlling physics still remains a challenge, there have been significant advances in recent decades. These advances are related primarily to the exponential growth of computational power, the development of more accurate equations of state, improvements in the ability to represent heterogeneity and reservoir geometry, and more robust nonlinear solution schemes. The work described in this paper documents the development and linkage of several fully-coupled and fully-implicit modeling tools. These tools simulate: (1) the dynamics of fluid flow, heat transport, and quasi-static rock mechanics; (2) seismic wave propagation from the sources of energy release through heterogeneous material; and (3) the soil-structural damage resulting from ground acceleration. These tools are developed in Idaho National Laboratory's parallel Multiphysics Object Oriented Simulation Environment, and are integrated together using a global implicit approach. The governing equations are presented, the numerical approach for simultaneously solving and coupling the three coupling physics tools is discussed, and the data input and output methodology is outlined. An example is presented to demonstrate the capabilities of the coupled multiphysics approach. The example involves simulating a system conceptually similar to the geothermal development in Basel Switzerland, and the resultant induced seismicity, ground motion and structural damage is predicted.

  12. Effectiveness of helicopter versus ground ambulance services for interfacility transport.

    Science.gov (United States)

    Arfken, C L; Shapiro, M J; Bessey, P Q; Littenberg, B

    1998-10-01

    Helicopters provide rapid interfacility transport, but the effect on patients is largely unknown. Patients requested to be transported between facilities by helicopter were followed prospectively to determine survival, disability, health status, and health care utilization. A total of 1,234 patients were transported by the primary aeromedical company; 153 patients were transported by ground and 25 patients were transported by other aeromedical services because of weather or unavailability of aircraft. There were no differences at 30 days for survivors in disability, health status, or health care utilization. Nineteen percent of helicopter-transported patients died compared with 15% of those transported by ground (p=0.21). The patients transported by helicopter did not have improved outcomes compared with patients transported by ground. These data argue against a large advantage of helicopters for interfacility transport. A randomized trial is needed to address these issues conclusively.

  13. Near-fault directivity pulse-like ground motion effect on high-speed railway bridge

    Institute of Scientific and Technical Information of China (English)

    陈令坤; 张楠; 蒋丽忠; 曾志平; 陈格威; 国巍

    2014-01-01

    The vehicle-track-bridge (VTB) element was used to investigate how a high-speed railway bridge reacted when it was subjected to near-fault directivity pulse-like ground motions. Based on the PEER NAG Strong Ground Motion Database, the spatial analysis model of a vehicle-bridge system was developed, the VTB element was derived to simulate the interaction of train and bridge, and the elasto-plastic seismic responses of the bridge were calculated. The calculation results show that girder and pier top displacement, and bending moment of the pier base increase subjected to near-fault directivity pulse-like ground motion compared to far-field earthquakes, and the greater deformation responses in near-fault shaking are associated with fewer reversed cycles of loading. The hysteretic characteristics of the pier subjected to a near-fault directivity pulse-like earthquake should be explicitly expressed as the bending moment-rotation relationship of the pier base, which is characterized by the centrally strengthened hysteretic cycles at some point of the loading time-history curve. The results show that there is an amplification of the vertical deflection in the girder’s mid-span owing to the high vertical ground motion. In light of these findings, the effect of the vertical ground motion should be used to adjust the unconservative amplification constant 2/3 of the vertical-to-horizontal peak ground motion ratio in the seismic design of bridge.

  14. Ground state of a confined Yukawa plasma including correlation effects

    CERN Document Server

    Henning, C; Filinov, A; Piel, A; Bonitz, M

    2007-01-01

    The ground state of an externally confined one-component Yukawa plasma is derived analytically using the local density approximation (LDA). In particular, the radial density profile is computed. The results are compared with the recently obtained mean-field (MF) density profile \\cite{henning.pre06}. While the MF results are more accurate for weak screening, LDA with correlations included yields the proper description for large screening. By comparison with first-principle simulations for three-dimensional spherical Yukawa crystals we demonstrate that both approximations complement each other. Together they accurately describe the density profile in the full range of screening parameters.

  15. Computer predictions of ground storage effects on performance of Galileo and ISPM generators

    Science.gov (United States)

    Chmielewski, A.

    1983-01-01

    Radioisotope Thermoelectric Generators (RTG) that will supply electrical power to the Galileo and International Solar Polar Mission (ISPM) spacecraft are exposed to several degradation mechanisms during the prolonged ground storage before launch. To assess the effect of storage on the RTG flight performance, a computer code has been developed which simulates all known degradation mechanisms that occur in an RTG during storage and flight. The modeling of these mechanisms and their impact on the RTG performance are discussed.

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

    National Research Council Canada - National Science Library

    Pedro Sanchez-Cuevas; Guillermo Heredia; Anibal Ollero

    2017-01-01

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

  17. Effects of 3D random correlated velocity perturbations on predicted ground motions

    Science.gov (United States)

    Hartzell, S.; Harmsen, S.; Frankel, A.

    2010-01-01

    Three-dimensional, finite-difference simulations of a realistic finite-fault rupture on the southern Hayward fault are used to evaluate the effects of random, correlated velocity perturbations on predicted ground motions. Velocity perturbations are added to a three-dimensional (3D) regional seismic velocity model of the San Francisco Bay Area using a 3D von Karman random medium. Velocity correlation lengths of 5 and 10 km and standard deviations in the velocity of 5% and 10% are considered. The results show that significant deviations in predicted ground velocities are seen in the calculated frequency range (≤1 Hz) for standard deviations in velocity of 5% to 10%. These results have implications for the practical limits on the accuracy of scenario ground-motion calculations and on retrieval of source parameters using higher-frequency, strong-motion data.

  18. EFFECT OF SANTA ROSA LAKE ON GROUND WATER FLOW TO THE PECOS RIVER, NEW MEXICO.

    Science.gov (United States)

    Risser, Dennis W.

    1985-01-01

    In 1980, Santa Rosa Dam began impounding water on the Pecos River about 7 miles (11 kilometers) north of Santa Rosa, New Mexico, to provide flood control and storage for irrigation. Santa Rosa Lake has caused changes in the ground water flow system, which may cause changes in the streamflow of the Pecos River that cannot be detected at the present streamflow-gaging stations, which are used to administer water rights along the Pecos River. The effect of the lake on streamflow was investigated using a three-dimensional ground water flow model. These simulations indicated that the net change in ground water flow to the river would be almost zero if the lake were maintained at its flood control pool for 90 days.

  19. Refinements to the Graves and Pitarka (2010) Broadband Ground Motion Simulation Method

    Science.gov (United States)

    Graves, Robert; Arben Pitarka,

    2015-01-01

    This brief article describes refinements to the Graves and Pitarka (2010) broadband ground motion simulation methodology (GP2010 hereafter) that have been implemented in version 14.3 of the SCEC Broadband Platform (BBP). The updated version of our method on the current SCEC BBP is referred to as GP14.3. Our simulation technique is a hybrid approach that combines low-­‐frequency and high-­‐frequency motions computed with different methods into a single broadband response. The separate low-­‐ and high-­‐frequency components have traditionally been called “deterministic” and “stochastic”, respectively; however, this nomenclature is an oversimplification. In reality, the low-­‐frequency approach includes many stochastic elements, and likewise, the high-­‐frequency approach includes many deterministic elements (e.g., Pulido and Kubo, 2004; Hartzell et al., 2005; Liu et al., 2006; Frankel, 2009; Graves and Pitarka, 2010; Mai et al., 2010). While the traditional terminology will likely remain in use by the broader modeling community, in this paper we will refer to these using the generic terminology “low-­‐frequency” and “high-­‐ frequency” approaches. Furthermore, one of the primary goals in refining our methodology is to provide a smoother and more consistent transition between the low-­‐ and high-­‐ frequency calculations, with the ultimate objective being the development of a single unified modeling approach that can be applied over a broad frequency band. GP2010 was validated by modeling recorded strong motions from four California earthquakes. While the method performed well overall, several issues were identified including the tendency to over-­‐predict the level of longer period (2-­‐5 sec) motions and the effects of rupture directivity. The refinements incorporated in GP14.3 are aimed at addressing these issues with application to the simulation of earthquakes in Western US (WUS). These refinements include the

  20. Simulations of direct and reflected wave trajectories for ground-based GNSS-R experiments

    Science.gov (United States)

    Roussel, N.; Frappart, F.; Ramillien, G.; Darrozes, J.; Desjardins, C.; Gegout, P.; Pérosanz, F.; Biancale, R.

    2014-10-01

    The detection of Global Navigation Satellite System (GNSS) signals that are reflected off the surface, along with the reception of direct GNSS signals, offers a unique opportunity to monitor water level variations over land and ocean. The time delay between the reception of the direct and reflected signals gives access to the altitude of the receiver over the reflecting surface. The field of view of the receiver is highly dependent on both the orbits of the GNSS satellites and the configuration of the study site geometries. A simulator has been developed to determine the location of the reflection points on the surface accurately by modeling the trajectories of GNSS electromagnetic waves that are reflected by the surface of the Earth. Only the geometric problem was considered using a specular reflection assumption. The orbit of the GNSS constellation satellites (mainly GPS, GLONASS and Galileo), and the position of a fixed receiver, are used as inputs. Four different simulation modes are proposed, depending on the choice of the Earth surface model (local plane, osculating sphere or ellipsoid) and the consideration of topography likely to cause masking effects. Angular refraction effects derived from adaptive mapping functions are also taken into account. This simulator was developed to determine where the GNSS-R receivers should be located to monitor a given study area efficiently. In this study, two test sites were considered: the first one at the top of the 65 m Cordouan lighthouse in the Gironde estuary, France, and the second one on the shore of Lake Geneva (50 m above the reflecting surface), at the border between France and Switzerland. This site is hidden by mountains in the south (orthometric altitude up to 2000 m), and overlooking the lake in the north (orthometric altitude of 370 m). For this second test site configuration, reflections occur until 560 m from the receiver. The planimetric (arc length) differences (or altimetric difference as WGS84

  1. The SCEC Broadband Platform: A Collaborative Open-Source Software Package for Strong Ground Motion Simulation and Validation

    Science.gov (United States)

    Silva, F.; Maechling, P. J.; Goulet, C. A.; Somerville, P.; Jordan, T. H.

    2014-12-01

    The Southern California Earthquake Center (SCEC) Broadband Platform is a collaborative software development project involving geoscientists, earthquake engineers, graduate students, and the SCEC Community Modeling Environment. The SCEC Broadband Platform (BBP) is open-source scientific software that can generate broadband (0-100Hz) ground motions for earthquakes, integrating complex scientific modules that implement rupture generation, low and high-frequency seismogram synthesis, non-linear site effects calculation, and visualization into a software system that supports easy on-demand computation of seismograms. The Broadband Platform operates in two primary modes: validation simulations and scenario simulations. In validation mode, the Platform runs earthquake rupture and wave propagation modeling software to calculate seismograms for a well-observed historical earthquake. Then, the BBP calculates a number of goodness of fit measurements that quantify how well the model-based broadband seismograms match the observed seismograms for a certain event. Based on these results, the Platform can be used to tune and validate different numerical modeling techniques. In scenario mode, the Broadband Platform can run simulations for hypothetical (scenario) earthquakes. In this mode, users input an earthquake description, a list of station names and locations, and a 1D velocity model for their region of interest, and the Broadband Platform software then calculates ground motions for the specified stations. Working in close collaboration with scientists and research engineers, the SCEC software development group continues to add new capabilities to the Broadband Platform and to release new versions as open-source scientific software distributions that can be compiled and run on many Linux computer systems. Our latest release includes 5 simulation methods, 7 simulation regions covering California, Japan, and Eastern North America, the ability to compare simulation results

  2. Does Suspected Sleep Disordered Breathing Impact on the Sleep and Performance of Firefighting Volunteers during a Simulated Fire Ground Campaign?

    Science.gov (United States)

    Jay, Sarah M; Smith, Bradley P; Windler, Samantha; Dorrian, Jillian; Ferguson, Sally A

    2016-01-29

    Adequate sleep is fundamental to workplace performance. For volunteer firefighters who work in safety critical roles, poor performance at work can be life threatening. Extended shifts and sleeping conditions negatively impact sleep during multi-day fire suppression campaigns. Having sleep disordered breathing (SDB) could contribute further to sleep deficits. Our aim was to investigate whether those with suspected SDB slept and performed more poorly during a fire ground simulation involving sleep restriction. Participants, n = 20 participated in a 3-day-4-night fire ground simulation. Based on oximetry desaturation index data collected during their participation, participants were retrospectively allocated to either a SDB (n = 8) or a non-SDB group (n = 12). The simulation began with an 8 h Baseline sleep (BL) followed by two nights of restricted (4 h) sleep and an 8 h recovery sleep (R). All sleeps were recorded using a standard electroencephalography (EEG) montage as well as oxygen saturation. During the day, participants completed neurobehavioral (response time, lapses and subjective fatigue) tasks. Mixed effects ANOVA were used to compare differences in sleep and wake variables. Analyses revealed a main effect of group for Total sleep (TST), REM , wake after sleep onset (WASO) and Arousals/h with the SDB group obtaining less TST and REM and greater WASO and Arousals/h. The group × night interaction was significant for N3 with the SDB group obtaining 42 min less during BL. There was a significant main effect of day for RRT, lapses and subjective fatigue and a significant day × group interaction for RRT. Overall, the SDB group slept less, experienced more disturbed sleep and had poorer response time performance, which was exacerbated by the second night of sleep restriction. This could present a safety concern, particularly during longer campaigns and is worthy of further investigation. In addition, we would recommend promotion of awareness of SDB, its symptoms

  3. Does Suspected Sleep Disordered Breathing Impact on the Sleep and Performance of Firefighting Volunteers during a Simulated Fire Ground Campaign?

    Directory of Open Access Journals (Sweden)

    Sarah M. Jay

    2016-01-01

    Full Text Available Adequate sleep is fundamental to workplace performance. For volunteer firefighters who work in safety critical roles, poor performance at work can be life threatening. Extended shifts and sleeping conditions negatively impact sleep during multi-day fire suppression campaigns. Having sleep disordered breathing (SDB could contribute further to sleep deficits. Our aim was to investigate whether those with suspected SDB slept and performed more poorly during a fire ground simulation involving sleep restriction. Participants, n = 20 participated in a 3-day-4-night fire ground simulation. Based on oximetry desaturation index data collected during their participation, participants were retrospectively allocated to either a SDB (n = 8 or a non-SDB group (n = 12. The simulation began with an 8 h Baseline sleep (BL followed by two nights of restricted (4 h sleep and an 8 h recovery sleep (R. All sleeps were recorded using a standard electroencephalography (EEG montage as well as oxygen saturation. During the day, participants completed neurobehavioral (response time, lapses and subjective fatigue tasks. Mixed effects ANOVA were used to compare differences in sleep and wake variables. Analyses revealed a main effect of group for Total sleep (TST, REM , wake after sleep onset (WASO and Arousals/h with the SDB group obtaining less TST and REM and greater WASO and Arousals/h. The group × night interaction was significant for N3 with the SDB group obtaining 42 min less during BL. There was a significant main effect of day for RRT, lapses and subjective fatigue and a significant day × group interaction for RRT. Overall, the SDB group slept less, experienced more disturbed sleep and had poorer response time performance, which was exacerbated by the second night of sleep restriction. This could present a safety concern, particularly during longer campaigns and is worthy of further investigation. In addition, we would recommend promotion of awareness of SDB, its

  4. DEVELOPMENT OF A POPULATION BALANCE MODEL TO SIMULATE FRACTIONATION OF GROUND SWITCHGRASS

    Energy Technology Data Exchange (ETDEWEB)

    Naimi, L.J. [University of British Columbia, Vancouver; Bi, X.T. [University of British Columbia, Vancouver; Lau, A.K. [University of British Columbia, Vancouver; Sokhansanj, Shahabaddine [ORNL; Womac, A.R. [University of Tennessee, Knoxville (UTK); Igathinathane, C. [North Dakota State University; Sowlati, T. [University of British Columbia, Vancouver; Melin, Staffan [Delta Research Corporation; Emami, M. [University of British Columbia, Vancouver; Afzal, M [University of New Brunswick

    2011-01-01

    The population balance model represents a time-dependent formulation of mass conservation for a ground biomass that flows through a set of sieves. The model is suitable for predicting the change in size and distribution of ground biomass while taking into account the flow rate processes of particles through a grinder. This article describes the development and application of this model to a switchgrass grinding operation. The mass conservation formulation of the model contains two parameters: breakage rate and breakage ratio. A laboratory knife mill was modified to act as a batch or flow-through grinder. The ground switchgrass was analyzed over a set of six Tyler sieves with apertures ranging from 5.66 mm (top sieve) to 1 mm (bottom sieve). The breakage rate was estimated from the sieving tests. For estimating the breakage ratio, each of the six fractions was further ground and sieved to 11 fractions on a set of sieves with apertures ranging from 5.66 to 0.25 mm (and pan). These data formed a matrix of values for determining the breakage ratio. Using the two estimated parameters, the transient population balance model was solved numerically. Results indicated that the population balance model generally underpredicted the fractions remaining on sieves with 5.66, 4.00, and 2.83 mm apertures and overpredicted fractions remaining on sieves with 2.00, 1.41, and 1.00 mm apertures. These trends were similar for both the batch and flow-through grinder configurations. The root mean square of residuals (RSE), representing the difference between experimental and simulated mass of fractions, was 0.32 g for batch grinding and 0.1 g for flow-through grinding. The breakage rate exhibited a linear function of the logarithm of particle size, with a regression coefficient of 0.99.

  5. Hydrogeology of, and Simulation of Ground-Water Flow In, the Pohatcong Valley, Warren County, New Jersey

    Science.gov (United States)

    Carleton, Glen B.; Gordon, Alison D.

    2007-01-01

    A numerical ground-water-flow model was constructed to simulate ground-water flow in the Pohatcong Valley, including the area within the U.S. Environmental Protection Agency Pohatcong Valley Ground Water Contamination Site. The area is underlain by glacial till, alluvial sediments, and weathered and competent carbonate bedrock. The northwestern and southeastern valley boundaries are regional-scale thrust faults and ridges underlain by crystalline rocks. The unconsolidated sediments and weathered bedrock form a minor surficial aquifer and the carbonate rocks form a highly transmissive fractured-rock aquifer. Ground-water flow in the carbonate rocks is primarily downvalley towards the Delaware River, but the water discharges through the surficial aquifer to Pohatcong Creek under typical conditions. The hydraulic characteristics of the carbonate-rock aquifer are highly heterogeneous. Horizontal hydraulic conductivities span nearly five orders of magnitude, from 0.5 feet per day (ft/d) to 1,800 ft/d. The maximum transmissivity calculated is 37,000 feet squared per day. The horizontal hydraulic conductivities calculated from aquifer tests using public supply wells open to the Leithsville Formation and Allentown Dolomite are 34 ft/d (effective hydraulic conductivity) and 85 to 190 ft/d (minimum and maximum hydraulic conductivity, respectively, yielding a horizontal anisotropy ratio of 0.46). Stream base-flow data were used to estimate the net gain (or loss) for selected reaches on Brass Castle Creek, Shabbecong Creek, three smaller tributaries to Pohatcong Creek, and for five reaches on Pohatcong Creek. Estimated mean annual base flows for Brass Castle Creek, Pohatcong Creek at New Village, and Pohatcong Creek at Carpentersville (from correlations of partial- and continuous-record stations) are 2.4, 25, and 45 cubic feet per second (ft3/s) (10, 10, and 11 inches per year (in/yr)), respectively. Ground-water ages estimated using sulfur hexafluoride (SF6

  6. Numerical models for ground deformation and gravity changes during volcanic unrest: simulating the hydrothermal system dynamics of a restless caldera

    Science.gov (United States)

    Coco, A.; Gottsmann, J.; Whitaker, F.; Rust, A.; Currenti, G.; Jasim, A.; Bunney, S.

    2016-04-01

    Ground deformation and gravity changes in restless calderas during periods of unrest can signal an impending eruption and thus must be correctly interpreted for hazard evaluation. It is critical to differentiate variation of geophysical observables related to volume and pressure changes induced by magma migration from shallow hydrothermal activity associated with hot fluids of magmatic origin rising from depth. In this paper we present a numerical model to evaluate the thermo-poroelastic response of the hydrothermal system in a caldera setting by simulating pore pressure and thermal expansion associated with deep injection of hot fluids (water and carbon dioxide). Hydrothermal fluid circulation is simulated using TOUGH2, a multicomponent multiphase simulator of fluid flows in porous media. Changes in pore pressure and temperature are then evaluated and fed into a thermo-poroelastic model (one-way coupling), which is based on a finite-difference numerical method designed for axi-symmetric problems in unbounded domains.Informed by constraints available for the Campi Flegrei caldera (Italy), a series of simulations assess the influence of fluid injection rates and mechanical properties on the hydrothermal system, uplift and gravity. Heterogeneities in hydrological and mechanical properties associated with the presence of ring faults are a key determinant of the fluid flow pattern and consequently the geophysical observables. Peaks (in absolute value) of uplift and gravity change profiles computed at the ground surface are located close to injection points (namely at the centre of the model and fault areas). Temporal evolution of the ground deformation indicates that the contribution of thermal effects to the total uplift is almost negligible with respect to the pore pressure contribution during the first years of the unrest, but increases in time and becomes dominant after a long period of the simulation. After a transient increase over the first years of unrest

  7. Numerical models for ground deformation and gravity changes during volcanic unrest: simulating the hydrothermal system dynamics of an active caldera

    Directory of Open Access Journals (Sweden)

    A. Coco

    2015-08-01

    Full Text Available Ground deformation and gravity changes in active calderas during periods of unrest can signal an impending eruption and thus must be correctly interpreted for hazard evaluation. It is critical to differentiate variation of geophysical observables related to volume and pressure changes induced by magma migration from shallow hydrothermal activity associated with hot fluids of magmatic origin rising from depth. In this paper we present a numerical model to evaluate the thermo-poroelastic response of the hydrothermal system in a caldera setting by simulating pore pressure and thermal expansion associated with deep injection of hot fluids (water and carbon dioxide. Hydrothermal fluid circulation is simulated using TOUGH2, a multicomponent multiphase simulator of fluid flows in porous media. Changes in pore pressure and temperature are then evaluated and fed into a thermo-poroelastic model (one-way coupling, which is based on a finite-difference numerical method designed for axi-symmetric problems in unbounded domains. Based on data for the Campi Flegrei caldera (Italy, a series of simulations assess the influence of fluid injection rates and mechanical properties on the hydrothermal system, uplift and gravity. Heterogeneities in hydrological and mechanical properties associated with the presence of ring faults are a key determinant of the fluid flow pattern and consequently the geophysical observables. Peaks (in absolute value of uplift and gravity change profiles computed at the ground surface are located close to injection points (namely at the centre of the model and fault areas. Temporal evolution of the ground deformation indicates that the contribution of thermal effects to the total uplift is almost negligible with respect to the pore pressure contribution during the first years of the unrest, but increases in time and becomes dominant after a long period of the simulation. After a transient increase over the first years of unrest, gravity

  8. Effect of ground motion from nuclear excavation: interim canal studies

    Energy Technology Data Exchange (ETDEWEB)

    King, C. Y.; Nadolski, M. E.

    1969-09-01

    The effect of ground motion due to nuclear excavation of a sea-level canal at two alternative routes, 17A and 25E, are discussed from the aspects of motion prediction and structural response. The importance of the high-rise building problem is stressed because of its complexity. Several damage criteria are summarized for advance planning of excavation and operation. The 1964 shot schedule and the latest revised schedule are included for comparison.

  9. 3D visual analysis tool in support of the SANDF's growing ground based air defence simulation capability

    CSIR Research Space (South Africa)

    Duvenhage, B

    2007-10-01

    Full Text Available A 3D visual analysis tool has been developed to add value to the SANDF's growing Ground Based Air Defence (GBAD) System of Systems simulation capability. A time based XML interface between the simulation and analysis tool, via a TCP connection or a...

  10. Functional proteomic analysis revealed ground-base ion radiations cannot reflect biological effects of space radiations of rice

    Science.gov (United States)

    Wang, Wei; Sun, Yeqing; Zhao, Qian; Han, Lu

    2016-07-01

    Highly ionizing radiation (HZE) in space is considered as main factor causing biological effects. Radiobiological studies during space flights are unrepeatable due to the variable space radiation environment, ground-base ion radiations are usually performed to simulate of the space biological effect. Spaceflights present a low-dose rate (0.1˜~0.3mGy/day) radiation environment inside aerocrafts while ground-base ion radiations present a much higher dose rate (100˜~500mGy/min). Whether ground-base ion radiation can reflect effects of space radiation is worth of evaluation. In this research, we compared the functional proteomic profiles of rice plants between on-ground simulated HZE particle radiation and spaceflight treatments. Three independent ground-base seed ionizing radiation experiments with different cumulative doses (dose range: 2˜~20000mGy) and different liner energy transfer (LET) values (13.3˜~500keV/μμm) and two independent seed spaceflight experiments onboard Chinese 20th satellite and SZ-6 spacecraft were carried out. Alterations in the proteome were analyzed by two-dimensional difference gel electrophoresis (2-D DIGE) with MALDI-TOF/TOF mass spectrometry identifications. 45 and 59 proteins showed significant (pmetabolic process, protein folding and phosphorylation. The results implied that ground-base radiations cannot truly reflect effects of spaceflight radiations, ground-base radiation was a kind of indirect effect to rice causing oxidation and metabolism stresses, but space radiation was a kind of direct effect leading to macromolecule (DNA and protein) damage and signal pathway disorders. This functional proteomic analysis work might provide a new evaluation method for further on-ground simulated HZE radiation experiments.

  11. Observed and simulated ground motions in the San Bernardino basin region for the Hector Mine, California, earthquake

    Science.gov (United States)

    Graves, R.W.; Wald, D.J.

    2004-01-01

    During the MW 7.1 Hector Mine earthquake, peak ground velocities recorded at sites in the central San Bernardino basin region were up to 2 times larger and had significantly longer durations of strong shaking than sites just outside the basin. To better understand the effects of 3D structure on the long-period ground-motion response in this region, we have performed finite-difference simulations for this earthquake. The simulations are numerically accurate for periods of 2 sec and longer and incorporate the detailed spatial and temporal heterogeneity of source rupture, as well as complex 3D basin structure. Here, we analyze three models of the San Bernardino basin: model A (with structural constraints from gravity and seismic reflection data), model F (water well and seismic refraction data), and the Southern California Earthquake Center version 3 model (hydrologic and seismic refraction data). Models A and F are characterized by a gradual increase in sediment thickness toward the south with an abrupt step-up in the basement surface across the San Jacinto fault. The basin structure in the SCEC version 3 model has a nearly uniform sediment thickness of 1 km with little basement topography along the San Jacinto fault. In models A and F, we impose a layered velocity structure within the sediments based on the seismic refraction data and an assumed depth-dependent Vp/Vs ratio. Sediment velocities within the SCEC version 3 model are given by a smoothly varying rule-based function that is calibrated to the seismic refraction measurements. Due to computational limitations, the minimum shear-wave velocity is fixed at 600 m/sec in all of the models. Ground-motion simulations for both models A and F provide a reasonably good match to the amplitude and waveform characteristics of the recorded motions. In these models, surface waves are generated as energy enters the basin through the gradually sloping northern margin. Due to the basement step along the San Jacinto fault, the

  12. Mechanical stimulation of the foot sole in a supine position for ground reaction force simulation

    OpenAIRE

    2014-01-01

    Background:\\ud To promote early rehabilitation of walking, gait training can start even when patients are on bed rest. Supine stepping in the early phase after injury is proposed to maximise the beneficial effects of gait restoration. In this training paradigm, mechanical loading on the sole of the foot is required to mimic the ground reaction forces that occur during overground walking. A pneumatic shoe platform was developed to produce adjustable forces on the heel and the forefoot with an ...

  13. S2-Project: Near-fault earthquake ground motion simulation in the Sulmona alluvial basin

    Science.gov (United States)

    Faccioli, E.; Stupazzini, M.; Galadini, F.; Gori, S.

    2008-12-01

    Recently the Italian Department of Civil Protection (DPC), in cooperation with Istituto Nazionale di Geofisica e Vulcanologia (INGV) has promoted the 'S2' research project (http://nuovoprogettoesse2.stru.polimi.it/) aimed at the design, testing and application of an open-source code for seismic hazard assessment (SHA). The tool envisaged will likely differ in several important respects from an existing international initiative (Open SHA, Field et al., 2003). In particular, while "the OpenSHA collaboration model envisions scientists developing their own attenuation relationships and earthquake rupture forecasts, which they will deploy and maintain in their own systems" , the main purpose of S2 project is to provide a flexible computational tool for SHA, primarily suited for the needs of DPC, which not necessarily are scientific needs. Within S2, a crucial issue is to make alternative approaches available to quantify the ground motion, with emphasis on the near field region. The SHA architecture envisaged will allow for the use of ground motion descriptions other than those yielded by empirical attenuation equations, for instance user generated motions provided by deterministic source and wave propagation simulations. In this contribution, after a brief presentation of Project S2, we intend to illustrate some preliminary 3D scenario simulations performed in the alluvial basin of Sulmona (Central Italy), as an example of the type of descriptions that can be handled in the future SHA architecture. In detail, we selected some seismogenic sources (from the DISS database), believed to be responsible for a number of destructive historical earthquakes, and derive from them a family of simplified geometrical and mechanical source models spanning across a reasonable range of parameters, so that the extent of the main uncertainties can be covered. Then, purely deterministic (for frequencies Element (SE) method, extensively published by Faccioli and his co-workers, and

  14. Numerical simulation of high-speed train induced ground vibrations using 2.5D finite element approach

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    An efficient 2.5D finite element numerical modeling approach was developed to simulate wave motions generated in ground by high-speed train passages. Fourier transform with respect to the coordinate in the track direction was applied to re-ducing the three-dimensional dynamic problem to a plane strain problem which has been solved in a section perpendicular to the track direction. In this study, the track structure and supporting ballast layer were simplified as a composite Euler beam resting on the ground surface, while the ground with complicated geometry and physical properties was modeled by 2.5D quadrilateral elements. Wave dissipation into the far field was dealt with the transmitting boundary constructed with fre-quency-dependent dashpots. Three-dimensional responses of track structure and ground were obtained from the wavenumber expansion in the track direction. The simulated wave motions in ground were interpreted for train moving loads traveling at speeds below or above the critical velocity of a specific track-ground system. It is found that, in the soft ground area, the high-speed train operations can enter the transonic range, which can lead to resonances of the track structure and the sup-porting ground. The strong vibration will endanger the safe operations of high-speed train and accelerate the deterioration of railway structure.

  15. Numerical simulation of high-speed train induced ground vibrations using 2.5D finite element approach

    Institute of Scientific and Technical Information of China (English)

    BIAN XueCheng; OHEN YunMin; HU Ting

    2008-01-01

    An efficient 2.5D finite element numerical modeling approach was developed to simulate wave motions generated in ground by high-speed train passages.Fourier transform with respect to the coordinate in the track direction was applied to re-ducing the three-dimensional dynamic problem to a plane strain problem which has been solved in a section perpendicular to the track direction.In this study,the track structure and supporting ballast layer were simplified as a composite Euler beam resting on the ground surface,while the ground with complicated geometry and physical properties was modeled by 2.5D quadrilateral elements.Wave dissipation into the far field was dealt with the transmitting boundary constructed with fre-quency-dependent dashpots.Three-dimensional responses of track structure and ground were obtained from the wavenumber expansion in the track direction.The simulated wave motions in ground were interpreted for train moving loads traveling at speeds below or above the critical velocity of a specific track-ground system.It is found that,in the soft ground area,the high-speed train operations can enter the transonic range,which can lead to resonances of the track structure and the sup-porting ground.The strong vibration will endanger the safe operations of high-speed train and accelerate the deterioration of railway structure.

  16. Effects of a Group of High-Rise Structures on Ground Motions under Seismic Excitation

    Directory of Open Access Journals (Sweden)

    Qing-jun Chen

    2015-01-01

    Full Text Available A three-dimensional simulation was created to determine the seismic performance of coupled systems with a group of up to 100 pile-high-rise structures resting on soil layers using system modal, harmonic, and time domain analysis. The results demonstrated that the existence of a structural group mitigates the structural responses with respect to the single-structure-soil interaction (SSI and results in significantly nonuniform ground seismic motions. Due to the influence of a structural group, adjacent structures can exhibit fully alternating mechanical behavior, and buildings in the urban fringe are subjected to stronger shaking than downtown buildings. The overall trend of the influence of structural groups is that ground motions are lessened inside an urban area, and ground motions at the locations between structures differ from those at the locations of the structures. Moreover, the effective distance of a structural group on ground motions is associated with the urban width. Less distance between structures enhances the interaction effect. In addition, the soil properties can greatly influence the system’s seismic responses and can even completely change the effect trends. The results in our paper are consistent with the phenomena observed in the Mexico City earthquake and the 1976 earthquake in Friuli, Italy.

  17. Effects of Ground Conditions on Microbial Cementation in Soils

    Directory of Open Access Journals (Sweden)

    Daehyeon Kim

    2013-12-01

    Full Text Available The purpose of this study is to understand the effect of ground conditions on microbial cementation in cohesionless soils. Since the method of microbial cementation is still at the experimental stage, for its practical use in the field, a number of laboratory experiments are required for the quantification of microbial cementation under various ground conditions, such as relative densities, relative compactions and particle size distributions. In this study, in order to evaluate the effectiveness of microbial cementation in treated sands and silts, an experiment was performed for different relative densities of silica sands, for different relative compactions of silts and for different particle size distributions of weathered soils sampled from the field. Scanning electron microscope (SEM, X-ray diffraction (XRD, energy dispersive X-ray (EDX spectroscopy and mapping analyses were implemented for the quantification of the levels of microbial cementations for sand, silt and weathered soil specimens. Based on the test results, a considerable microbial cementation was estimated depending on the soil conditions; therefore, an implementation of this new type of bio-grouting on a weak foundation may be possible to increase the strength and stiffness of weak ground.

  18. DCCII-Based Novel Lossless Grounded Inductance Simulators With No Element Matching Constrains

    Directory of Open Access Journals (Sweden)

    B. Metin

    2014-04-01

    Full Text Available In 1996, the differential current conveyor (DCCII was introduced as a versatile active element with current differencing capability. Therefore, in this study, the usefulness of the DCCII is shown on six novel lossless grounded inductance simulator circuits. Proposed circuits simultaneously employ minimum number of elements, i.e. single DCCII, one capacitor, and two resistors. No passive element matching restriction is needed and all solutions are electronically tunable in case that one of resistors is replaced by MOSFET-based voltage-controlled resistor. The internal structure of the active element has been implemented using the TSMC 0.25 um SCN025 CMOS process BSIM3v3.1 parameters. Firstly, the performance of the selected inductor simulator is evaluated and subsequently verified in the design of 5th-order high-pass ladder and 2nd-order frequency filters. In addition, experimental results using commercially available AD844/ADs are given to verify the theoretical analysis and SPICE simulations.

  19. Sensitivity of Distributed Hydrologic Simulations to Ground and Satellite Based Rainfall Products

    Directory of Open Access Journals (Sweden)

    Singaiah Chintalapudi

    2014-05-01

    Full Text Available In this study, seven precipitation products (rain gauges, NEXRAD MPE, PERSIANN 0.25 degree, PERSIANN CCS-3hr, PERSIANN CCS-1hr, TRMM 3B42V7, and CMORPH were used to force a physically-based distributed hydrologic model. The model was driven by these products to simulate the hydrologic response of a 1232 km2 watershed in the Guadalupe River basin, Texas. Storm events in 2007 were used to analyze the precipitation products. Comparison with rain gauge observations reveals that there were significant biases in the satellite rainfall products and large variations in the estimated amounts. The radar basin average precipitation compared very well with the rain gauge product while the gauge-adjusted TRMM 3B42V7 precipitation compared best with observed rainfall among all satellite precipitation products. The NEXRAD MPE simulated streamflows matched the observed ones the best yielding the highest Nash-Sutcliffe Efficiency correlation coefficient values for both the July and August 2007 events. Simulations driven by TRMM 3B42V7 matched the observed streamflow better than other satellite products for both events. The PERSIANN coarse resolution product yielded better runoff results than the higher resolution product. The study reveals that satellite rainfall products are viable alternatives when rain gauge or ground radar observations are sparse or non-existent.

  20. An element-free Galerkin method for ground penetrating radar numerical simulation

    Institute of Scientific and Technical Information of China (English)

    冯德山; 郭荣文; 王洪华

    2015-01-01

    An element-free Galerkin method (EFGM) is used to solve the two-dimensional (2D) ground penetrating radar (GPR) modelling problems, due to its simple pre-processing, the absence of elements and high accuracy. Different from element-based numerical methods, this approach makes nodes free from the elemental restraint and avoids the explicit mesh discretization. First, we derived the boundary value problem for the 2D GPR simulation problems. Second, a penalty function approach and a boundary condition truncated method were used to enforce the essential and the absorbing boundary conditions, respectively. A three-layered GPR model was used to verify our element-free approach. The numerical solutions show that our solutions have an excellent agreement with solutions of a finite element method (FEM). Then, we used the EFGM to simulate one more complex model to show its capability and limitations. Simulation results show that one obvious advantage of EFGM is the absence of element mesh, which makes the method very flexible. Due to the use of MLS fitting, a key feature of EFM, is that both the dependent variable and its gradient are continuous and have high precision.

  1. Advanced Coupled Simulation of Borehole Thermal Energy Storage Systems and Above Ground Installations

    Science.gov (United States)

    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.

  2. Simulating Collective Effects on GPUs

    CERN Document Server

    AUTHOR|(CDS)2095754; Arbenz, Peter

    Computer simulations are an important tool to study the dynamics of charged particles in particle accelerators, with new hardware solutions such as GPUs providing a vast increase in computing power. In the accelerator physics domain simulations are used to understand instabilities arising due to collective e↵ects in high intensity beams which limit the accelerator performance. In this thesis PyHEADTAIL, a code to study collective effects in synchrotrons, is ported to GPUs using PyCUDA. The goal is to achieve a significant speedup while at the same time producing a simple interface for users and other developers. A speedup of 6 compared to the CPU version is achieved on a typical simulation study of instabilities in the Large Hadron Collider (LHC) at CERN.

  3. Appropriate Arrangement of Nori Aquafarming Grounds in the Ariake Sea on the Basis of Convective Dispersion Simulation Model

    Science.gov (United States)

    Tabata, Toshinori; Hiramatsu, Kazuaki; Harada, Masayoshi; Shiraishi, Hideto; Shuto, Toshio

    This study investigated appropriate arrangement of nori aquafarming grounds from the view point of nori growth in the Ariake Sea coastal waters. Databases of the sea-bed topography and nori aquafarming grounds were constructed using GIS. Then the tidal currents and salinity in the Ariake Sea were simulated using a two-dimensional depth-integrated model, which was developed by integrating the three-dimensional continuity, momentum, and diffusion equations. The wetting and drying scheme was also introduced to account for the appearance and disappearance of tidal flats. The velocities and directions of the simulated tidal currents, salinity, and tidal land appearance were in good agreement with observed data. Five scenarios considered by the Fukuoka Prefectural Government were introduced in the simulation model to identify the most appropriate arrangement. An experimental formula for nitrogen assimilation kinetics in the nori body was introduced to evaluate the simulation results for the five scenarios. The scenarios with a reduced density of aquafarming grounds had increased nori growth, suggesting that the arrangement of the aquafarming grounds affected the nori growth. The simulation results were used to identify the most appropriate arrangement of aquafarming grounds.

  4. Hydrology and simulation of ground-water flow in Kamas Valley, Summit County, Utah

    Science.gov (United States)

    Brooks, L.E.; Stolp, B.J.; Spangler, L.E.

    2003-01-01

    Kamas Valley, Utah, is located about 50 miles east of Salt Lake City and is undergoing residential development. The increasing number of wells and septic systems raised concerns of water managers and prompted this hydrologic study. About 350,000 acre-feet per year of surface water flows through Kamas Valley in the Weber River, Beaver Creek, and Provo River, which originate in the Uinta Mountains east of the study area. The ground-water system in this area consists of water in unconsolidated deposits and consolidated rock; water budgets indicate very little interaction between consolidated rock and unconsolidated deposits. Most recharge to consolidated rock occurs at higher altitudes in the mountains and discharges to streams and springs upgradient of Kamas Valley. About 38,000 acre-feet per year of water flows through the unconsolidated deposits in Kamas Valley. Most recharge is from irrigation and seepage from major streams; most discharge is to Beaver Creek in the middle part of the valley. Long-term water-level fluctuations range from about 3 to 17 feet. Seasonal fluctuations exceed 50 feet. Transmissivity varies over four orders of magnitude in both the unconsolidated deposits and consolidated rock and is typically 1,000 to 10,000 feet squared per day in unconsolidated deposits and 100 feet squared per day in consolidated rock as determined from specific capacity. Water samples collected from wells, streams, and springs had nitrate plus nitrite concentrations (as N) substantially less than 10 mg/L. Total and fecal coliform bacteria were detected in some surface-water samples and probably originate from livestock. Septic systems do not appear to be degrading water quality. A numerical ground-water flow model developed to test the conceptual understanding of the ground-water system adequately simulates water levels and flow in the unconsolidated deposits. Analyses of model fit and sensitivity were used to refine the conceptual and numerical models.

  5. Revisions to some parameters used in stochastic-method simulations of ground motion

    Science.gov (United States)

    Boore, David; Thompson, Eric M.

    2015-01-01

    The stochastic method of ground‐motion simulation specifies the amplitude spectrum as a function of magnitude (M) and distance (R). The manner in which the amplitude spectrum varies with M and R depends on physical‐based parameters that are often constrained by recorded motions for a particular region (e.g., stress parameter, geometrical spreading, quality factor, and crustal amplifications), which we refer to as the seismological model. The remaining ingredient for the stochastic method is the ground‐motion duration. Although the duration obviously affects the character of the ground motion in the time domain, it also significantly affects the response of a single‐degree‐of‐freedom oscillator. Recently published updates to the stochastic method include a new generalized double‐corner‐frequency source model, a new finite‐fault correction, a new parameterization of duration, and a new duration model for active crustal regions. In this article, we augment these updates with a new crustal amplification model and a new duration model for stable continental regions. Random‐vibration theory (RVT) provides a computationally efficient method to compute the peak oscillator response directly from the ground‐motion amplitude spectrum and duration. Because the correction factor used to account for the nonstationarity of the ground motion depends on the ground‐motion amplitude spectrum and duration, we also present new RVT correction factors for both active and stable regions.

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

    Science.gov (United States)

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

    2005-01-01

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

  7. First principles simulation technique for characterizing single event effects

    Institute of Scientific and Technical Information of China (English)

    Zhang Ke-Ying; Guo Hong-Xia; Luo Yin-Hong; Fan Ru-Yu; Chen Wei; Lin Dong-Sheng; Guo Gang; Yan Yi-Hua

    2011-01-01

    This paper develops a new simulation technique to characterize single event effects on semiconductor devices. The technique used to calculate the single event effects is developed according to the physical interaction mechanism of a single event effect. An application of the first principles simulation technique is performed to predict the ground-test single event upset effect on field-programmable gate arrays based on 0.25 μm advanced complementary metal-oxidesemiconductor technology. The agreement between the single event upset cross section accessed from a broad-beam heavy ion experiment and simulation shows that the simulation technique could be used to characterize the single event effects induced by heavy ions on a semiconductor device.

  8. Environmental Effect on Egress Simulation

    KAUST Repository

    Rodriguez, Samuel

    2012-01-01

    Evacuation and egress simulations can be a useful tool for studying the effect of design decisions on the flow of agent movement. This type of simulation can be used to determine before hand the effect of design decisions and enable exploration of potential improvements. In this work, we study at how agent egress is affected by the environment in real world and large scale virtual environments and investigate metrics to analyze the flow. Our work differs from many evacuation systems in that we support grouping restrictions between agents (e.g., families or other social groups traveling together), and model scenarios with multiple modes of transportation with physically realistic dynamics (e.g., individuals walk from a building to their own cars and leave only when all people in the group arrive).

  9. Methanogenic biodegradation of creosote contaminants in natural and simulated ground-water ecosystems

    Science.gov (United States)

    Godsy, E. Michael; Goerlitz, Donald; Grbic-Galic, Dunja

    1992-01-01

    Wastes from a wood preserving plant in Pensacola, Florida have contaminated the near-surface sand-and-gravel aquifer with creosote-derived compounds and pentachlorophenol. Contamination resulted from the discharge of plant waste waters to and subsequent seepage from unlined surface impoundments that were in direct hydraulic contact with the ground water. Two distinct phases resulted when the creosote and water mixed: a denser than water hydrocarbon phase that moved vertically downward, and an organic-rich aqueous phase that moved laterally with the ground-water flow. The aqueous phase is enriched in organic acids, phenolic compounds, single- and double-ring nitrogen, sulfur, and oxygen containing compounds, and single- and double-ring aromatic hydrocarbons. The ground water is devoid of dissolved O2, is 60-70% saturated with CH4 and contains H2S. Field analyses document a greater decrease in concentration of organic fatty acids, benzoic acid, phenol, 2-, 3-, 4-methylphenol, quinoline, isoquinoline, 1(2H)-quinolinone, and 2(1H)-isoquinolinone during downgradient movement in the aquifer than could be explained by dilution and/or dispersion. Laboratory microcosm studies have shown that within the study region, this effect can be attributed to microbial degradation to CH4 and CO2. A small but active methanogenic population was found on sediment materials taken from highly contaminated parts of the aquifer.

  10. Simulations of strong ground motion in SW Iberia for the 1969 February 28 (Ms = 8.0) and the 1755 November 1 (M ~ 8.5) earthquakes - II. Strong ground motion simulations

    Science.gov (United States)

    Grandin, Raphaël; Borges, José Fernando; Bezzeghoud, Mourad; Caldeira, Bento; Carrilho, Fernando

    2007-11-01

    This is the second paper of a series of two concerning strong ground motion in SW Iberia due to earthquakes originating from the adjacent Atlantic area. The aim of this paper is to use the velocity model that was proposed and validated in the companion paper for seismic intensity modelling of the 1969 (Ms = 8.0) and 1755 (M = 8.5-8.7) earthquakes. First, we propose a regression to convert simulated values of Peak Ground Velocity (PGV) into Modified Mercalli Intensity (MMI) in SW Iberia, and using this regression, we build synthetic isoseismal maps for a large (Ms = 8.0) earthquake that occurred in 1969. Based on information on the seismic source provided by various authors, we show that the velocity model effectively reproduces macroseismic observations in the whole region. We also confirm that seismic intensity distribution is very sensitive to a small number of source parameters: rupture directivity, fault strike and fault dimensions. Then, we extrapolate the method to the case of the great (M = 8.5-8.7) 1755 earthquake, for a series of hypotheses recently proposed by three authors about the location of the epicentral region. The model involving a subduction-related rupture in the Gulf of Cádiz results in excessive ground motion in northern Morocco, suggesting that the source of the 1755 earthquake should be located further west. A rupture along the western coast of Portugal, compatible with an activation of the passive western Iberian margin, would imply a relatively low average slip, which, alone, would could not account for the large tsunami observed in the whole northern Atlantic ocean. A seismic source located below the Gorringe Bank seems the most likely since it is more efficient in reproducing the distribution of high intensities in SW Iberia due to the 1755 earthquake.

  11. A novel approach for simulating the optical misalignment caused by satellite platform vibration in the ground test of satellite optical communication systems.

    Science.gov (United States)

    Wang, Qiang; Tan, Liying; Ma, Jing; Yu, Siyuan; Jiang, Yijun

    2012-01-16

    Satellite platform vibration causes the misalignment between incident direction of the beacon and optical axis of the satellite optical communication system, which also leads to the instability of the laser link and reduces the precision of the system. So how to simulate the satellite platform vibration is a very important work in the ground test of satellite optical communication systems. In general, a vibration device is used for simulating the satellite platform vibration, but the simulation effect is not ideal because of the limited randomness. An approach is reasonable, which uses a natural random process for simulating the satellite platform vibration. In this paper, we discuss feasibility of the concept that the effect of angle of arrival fluctuation is taken as an effective simulation of satellite platform vibration in the ground test of the satellite optical communication system. Spectrum characteristic of satellite platform vibration is introduced, referring to the model used by the European Space Agency (ESA) in the SILEX program and that given by National Aeronautics and Space Development Agency (NASDA) of Japan. Spectrum characteristic of angle of arrival fluctuation is analyzed based on the measured data from an 11.16km bi-directional free space laser transmission experiment. Spectrum characteristic of these two effects is compared. The results show that spectra of these two effects have similar variation trend with the variation of frequency and feasibility of the concept is proved by the comparison results. At last the procedure of this method is proposed, which uses the power spectra of angle of arrival fluctuation to simulate that of the satellite platform vibration. The new approach is good for the ground test of satellite optical communication systems.

  12. Performance of Irikura Recipe Rupture Model Generator in Earthquake Ground Motion Simulations with Graves and Pitarka Hybrid Approach

    Science.gov (United States)

    Pitarka, Arben; Graves, Robert; Irikura, Kojiro; Miyake, Hiroe; Rodgers, Arthur

    2017-02-01

    We analyzed the performance of the Irikura and Miyake (Pure and Applied Geophysics 168(2011):85-104, 2011) (IM2011) asperity-based kinematic rupture model generator, as implemented in the hybrid broadband ground motion simulation methodology of Graves and Pitarka (Bulletin of the Seismological Society of America 100(5A):2095-2123, 2010), for simulating ground motion from crustal earthquakes of intermediate size. The primary objective of our study is to investigate the transportability of IM2011 into the framework used by the Southern California Earthquake Center broadband simulation platform. In our analysis, we performed broadband (0-20 Hz) ground motion simulations for a suite of M6.7 crustal scenario earthquakes in a hard rock seismic velocity structure using rupture models produced with both IM2011 and the rupture generation method of Graves and Pitarka (Bulletin of the Seismological Society of America, 2016) (GP2016). The level of simulated ground motions for the two approaches compare favorably with median estimates obtained from the 2014 Next Generation Attenuation-West2 Project (NGA-West2) ground motion prediction equations (GMPEs) over the frequency band 0.1-10 Hz and for distances out to 22 km from the fault. We also found that, compared to GP2016, IM2011 generates ground motion with larger variability, particularly at near-fault distances (1 s). For this specific scenario, the largest systematic difference in ground motion level for the two approaches occurs in the period band 1-3 s where the IM2011 motions are about 20-30% lower than those for GP2016. We found that increasing the rupture speed by 20% on the asperities in IM2011 produced ground motions in the 1-3 s bandwidth that are in much closer agreement with the GMPE medians and similar to those obtained with GP2016. The potential implications of this modification for other rupture mechanisms and magnitudes are not yet fully understood, and this topic is the subject of ongoing study. We concluded

  13. Geohydrology, simulation of ground-water flow, and ground-water quality at two landfills, Marion County, Indiana. Water Resources Investigation

    Energy Technology Data Exchange (ETDEWEB)

    Duwelius, R.F.; Greeman, T.K.

    1989-01-01

    The report presents the results of a study to provide a quantitative evaluation of the ground-water flow system at the Julietta and Tibbs-Banta landfills and provide a general description of the ground-water quality beneath and near the two landfills. These objectives provide the information necessary to evaluate the effects of the landfills on ground-water quality. Geologic, hydrologic, and water-quality data were collected in 1985 and 1986 at the Julietta and Tibbs-Banta landfills to fulfill the study objectives. Ground-water models were used to investigate the flow systems and estimate the volume of flow at the landfills. The report includes descriptions of the data collection, geologic and hydrologic descriptions of the two landfills, and brief histories of trash and sludge disposal. Ground-water-flow models are described and estimates of the volume of flow are discussed. A description of the quality-assurance plan used in conjunction with the water-quality data collection and analysis is included. Water-quality data are presented with statistical summaries of ground-water quality related to well depth and position in the flow system.

  14. gprMax: Open source software to simulate electromagnetic wave propagation for Ground Penetrating Radar

    Science.gov (United States)

    Warren, Craig; Giannopoulos, Antonios; Giannakis, Iraklis

    2016-12-01

    gprMax is open source software that simulates electromagnetic wave propagation, using the Finite-Difference Time-Domain (FDTD) method, for the numerical modelling of Ground Penetrating Radar (GPR). gprMax was originally developed in 1996 when numerical modelling using the FDTD method and, in general, the numerical modelling of GPR were in their infancy. Current computing resources offer the opportunity to build detailed and complex FDTD models of GPR to an extent that was not previously possible. To enable these types of simulations to be more easily realised, and also to facilitate the addition of more advanced features, gprMax has been redeveloped and significantly modernised. The original C-based code has been completely rewritten using a combination of Python and Cython programming languages. Standard and robust file formats have been chosen for geometry and field output files. New advanced modelling features have been added including: an unsplit implementation of higher order Perfectly Matched Layers (PMLs) using a recursive integration approach; diagonally anisotropic materials; dispersive media using multi-pole Debye, Drude or Lorenz expressions; soil modelling using a semi-empirical formulation for dielectric properties and fractals for geometric characteristics; rough surface generation; and the ability to embed complex transducers and targets.

  15. Electromagnetic Simulations of Ground-Penetrating Radar Propagation near Lunar Pits and Lava Tubes

    Science.gov (United States)

    Zimmerman, M. I.; Carter, L. M.; Farrell, W. M.; Bleacher, J. E.; Petro, N. E.

    2013-01-01

    Placing an Orion capsule at the Earth-Moon L2 point (EML2) would potentially enable telerobotic operation of a rover on the lunar surface. The Human Exploration Virtual Institute (HEVI) is proposing that rover operations be carried out near one of the recently discovered lunar pits, which may provide radiation shielding for long duration human stays as well as a cross-disciplinary, science-rich target for nearer-term telerobotic exploration. Ground penetrating radar (GPR) instrumentation included onboard a rover has the potential to reveal many details of underground geologic structures near a pit, as well as characteristics of the pit itself. In the present work we employ the full-wave electromagnetic code MEEP to simulate such GPR reflections from a lunar pit and other subsurface features including lava tubes. These simulations will feed forward to mission concepts requiring knowledge of where to hide from harmful radiation and other environmental hazards such as plama charging and extreme diurnal temperatures.

  16. Ground-water system, estimation of aquifer hydraulic properties, and effects of pumping on ground-water flow in Triassic sedimentary rocks in and near Lansdale, Pennsylvania

    Science.gov (United States)

    Senior, Lisa A.; Goode, Daniel J.

    1999-01-01

    Ground water in Triassic-age sedimentary fractured-rock aquifers in the area of Lansdale, Pa., is used as drinking water and for industrial supply. In 1979, ground water in the Lansdale area was found to be contaminated with trichloroethylene, tetrachloroethylene, and other man-made organic compounds, and in 1989, the area was placed on the U.S. Environmental Protection Agency's (USEPA) National Priority List as the North Penn Area 6 site. To assist the USEPA in the hydrogeological assessment of the site, the U.S. Geological Survey began a study in 1995 to describe the ground-water system and to determine the effects of changes in the well pumping patterns on the direction of ground-water flow in the Lansdale area. This determination is based on hydrologic and geophysical data collected from 1995-98 and on results of the simulation of the regional ground-water-flow system by use of a numerical model.Correlation of natural-gamma logs indicate that the sedimentary rock beds strike generally northeast and dip at angles less than 30 degrees to the northwest. The ground-water system is confined or semi-confined, even at shallow depths; depth to bedrock commonly is less than 20 feet (6 meters); and depth to water commonly is about 15 to 60 feet (5 to 18 meters) below land surface. Single-well, aquifer-interval-isolation (packer) tests indicate that vertical permeability of the sedimentary rocks is low. Multiple-well aquifer tests indicate that the system is heterogeneous and that flow appears primarily in discrete zones parallel to bedding. Preferred horizontal flow along strike was not observed in the aquifer tests for wells open to the pumped interval. Water levels in wells that are open to the pumped interval, as projected along the dipping stratigraphy, are drawn down more than water levels in wells that do not intersect the pumped interval. A regional potentiometric map based on measured water levels indicates that ground water flows from Lansdale towards discharge

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

    Science.gov (United States)

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

    2003-01-01

    the compilation of geographic, geologic, and hydrologic data and estimation of hydraulic properties and flows. The model was calibrated to historical surface-water and ground-water flow for the period 1891-1993. Sources of water to the regional ground-water flow system are natural and artificial recharge, coastal landward flow from the ocean (seawater intrusion), storage in the coarse-grained beds, and water from compaction of fine-grained beds (aquitards). Inflows used in the regional flow model simulation include streamflows routed through the major rivers and tributaries; infiltration of mountain-front runoff and infiltration of precipitation on bedrock outcrops and on valley floors; and artificial ground-water recharge of diverted streamflow, irrigation return flow, and treated sewage effluent. Most natural recharge occurs through infiltration (losses) of streamflow within the major rivers and tributaries and the numerous arroyos that drain the mountain fronts of the basin. Total simulated natural recharge was about 114,100 acre-feet per year (acre-ft/yr) for 1984-93: 27,800 acre-ft/yr of mountain-front and bedrock recharge, 24,100 acre-ft/yr of valley-floor recharge, and 62,200 acre-ft/yr of net streamflow recharge. Artificial recharge (spreading of diverted streamflow, irrigation return, and sewage effluent) is a major source of ground-water replenishment. During the 1984-93 simulation period, the average rate of artificial recharge at the spreading grounds was about 54,400 acre-ft/yr, 13 percent less than the simulated natural recharge rate for streamflow infiltration within the major rivers and tributaries. Estimated recharge from infiltration of irrigation return flow on the valley floors averaged about 51,000 acre-ft/yr, and treated sewage effluent averaged about 9,000 acre-ft/yr. Artificial recharge as streamflow diversion to the spreading grounds has occurred since 1929, and treated-sewage effluent has been discharged to stream channels since 1930. Under

  18. Simulation of submillimetre atmospheric spectra for characterising potential ground-based remote sensing observations

    Science.gov (United States)

    Turner, Emma C.; Withington, Stafford; Newnham, David A.; Wadhams, Peter; Jones, Anna E.; Clancy, Robin

    2016-11-01

    The submillimetre is an understudied region of the Earth's atmospheric electromagnetic spectrum. Prior technological gaps and relatively high opacity due to the prevalence of rotational water vapour lines at these wavelengths have slowed progress from a ground-based remote sensing perspective; however, emerging superconducting detector technologies in the fields of astronomy offer the potential to address key atmospheric science challenges with new instrumental methods. A site study, with a focus on the polar regions, is performed to assess theoretical feasibility by simulating the downwelling (zenith angle = 0°) clear-sky submillimetre spectrum from 30 mm (10 GHz) to 150 µm (2000 GHz) at six locations under annual mean, summer, winter, daytime, night-time and low-humidity conditions. Vertical profiles of temperature, pressure and 28 atmospheric gases are constructed by combining radiosonde, meteorological reanalysis and atmospheric chemistry model data. The sensitivity of the simulated spectra to the choice of water vapour continuum model and spectroscopic line database is explored. For the atmospheric trace species hypobromous acid (HOBr), hydrogen bromide (HBr), perhydroxyl radical (HO2) and nitrous oxide (N2O) the emission lines producing the largest change in brightness temperature are identified. Signal strengths, centre frequencies, bandwidths, estimated minimum integration times and maximum receiver noise temperatures are determined for all cases. HOBr, HBr and HO2 produce brightness temperature peaks in the mK to µK range, whereas the N2O peaks are in the K range. The optimal submillimetre remote sensing lines for the four species are shown to vary significantly between location and scenario, strengthening the case for future hyperspectral instruments that measure over a broad wavelength range. The techniques presented here provide a framework that can be applied to additional species of interest and taken forward to simulate retrievals and guide the

  19. Ground shock from multiple earth penetrator bursts: Effects for hexagonal weapon arrays

    Energy Technology Data Exchange (ETDEWEB)

    Kmetyk, L.N.; Yarrington, P.

    1990-08-01

    Calculations have been performed with the HULL hydrocode to study ground shock effects for multiple earth penetrator weapon (EPW) bursts in hexagonal-close-packed (HCP) arrays. Several different calculational approaches were used to treat this problem. The first simulations involved two-dimensional (2D) calculations, where the hexagonal cross-section of a unit-cell in an effectively-infinite HCP array was approximated by an inscribed cylinder. Those calculations showed substantial ground shock enhancement below the center of the array. To refine the analysis, 3D unit-cell calculations were done where the actual hexagonal cross-section of the HCP array was modelled. Results of those calculations also suggested that the multiburst array would enhance ground shock effects over those for a single burst of comparable yield. Finally, 3D calculations were run in which an HCP array of seven bursts was modelled explicitly. In addition, the effects of non-simultaneity were investigated. Results of the seven-burst HCP array calculations were consistent with the unit-cell results and, in addition, provided information on the 3D lethal contour produced by such an array.

  20. Local site effects on weak and strong ground motion

    Science.gov (United States)

    Aki, Keiiti

    1993-02-01

    This is a review of the current state of the art in characterizing effects of local geology on ground motion. A new horizon is clear in this aspect of strong motion studies. Non-linear amplification at sediment sites appears to be more pervasive than seismologists used to think. Several recent observations about the weak motion and the strong motion suggest that the non-linear amplification at sediment sites may be very common. First, on average, the amplification is always greater at the younger sediment sites for all frequencies up to 12 Hz, in the case of weak motion; while the relation is reversed for frequencies higher than 5 Hz, in the case of strong motion. Secondly, the application of the amplification factor determined from weak motion overestimates significantly the strong motion at sediment sites observed during the Loma Prieta earthquake within the epicentral distance of about 50 km. Thirdly, the variance of peak ground acceleration around the mean curve decreases with the increasing earthquake magnitude. Finally, the above non-linear effects are expected from geotechnical studies both in the magnitude of departure from the linear prediction and in the threshold acceleration level beyond which the non-linearity begins.

  1. An Efficient approach for Shielding Effect of the Grounding Electrodes under Impulse-Current Voltage based on MATLAB

    Directory of Open Access Journals (Sweden)

    Kalyani Pole

    2012-06-01

    Full Text Available The lightning current waveform has a major influence on the dynamic performance of ground electrodes. While high lightning current intensity improves the dynamic grounding performance due to ionization of the soil, very fast fronted pulses might worsen the performance in case of inductive behaviour. The previous analysis has often been based on quasistatic approximation that is not applicable to very fast fronted pulses. Previous Research focused on analyzing the impulse current dispersal regularity of different branches when injecting at one point. Comparing with the leakage current distribution of a single ground electrode, it is found that the leakage currents along the branches increase with the distance to the current feed point, and the more conductors near the injection point, the more uneven the leakage current distribution is. In this paper by simulation result we indicate that shielding effect should be taken into account when analyzing the impulse characteristics of grounding electrodes. Based on the simulation results, new empirical formulas applicable for slow and very fast fronted lightning current pulses are proposed. The effects of the ionization of the soil are disregarded; therefore, the new formulas are applicable for a conservative estimate of the upper bound of the impulse impedance of ground electrodes. In this paper we also analyze and compare by the MATLAB. We also provide dynamic behavior of ground electrodes.

  2. Instrumentation for Ground-Based Testing in Simulated Space and Planetary Conditions

    Science.gov (United States)

    Kleiman, Jacob; Horodetsky, Sergey; Issoupov, Vitali

    This paper is an overview of instrumentation developed and created by ITL Inc. for simulated testing and performance evaluation of spacecraft materials, structures, mechanisms, assemblies and components in different space and planetary environments. The LEO Space Environment Simulator allows simulation of the synergistic effect of ultra-high vacuum conditions, 5 eV neutral atomic oxygen beams, Vacuum-Ultraviolet (VUV) and Near-Ultraviolet (NUV) radiation, and temperature conditions. The simulated space environmental conditions can be controlled in-situ using a quadruple mass-spectrometer, Time-of-Flight technique, as well as Quartz Crystal Microbalance sensors. The new NUV System is capable of delivering an NUV power intensity of up to 10 Equivalent Suns. The design of the system uses horizontal orientation of the 5 kW Mercury lamp, focusing of NUV radiation is achieved due to a parabolic reflector. To address the Lunar/Martian surface environments, the Planetary Environmental Simulator/Test Facility has been developed and built to allow for physical evaluation of the effects of the Lunar/Martian dust environments in conjunction with other factors (ultra-high vacuum or planetary atmospheric conditions, VUV/NUV radiation, thermal cycling, and darkness). The ASTM E 595/ASTM E 1559 Outgassing Test Facility provides the means for the outgassing test of materials with the objective to select materials with low outgassing properties for spacecraft use and allows to determine the following outgassing parameters: Total Mass Loss, Collected Volatile Condensable Materials, and Water Vapor Regained.

  3. Simulation of ground-water flow in the Albuquerque Basin, central New Mexico, 1901-1994, with projections to 2020

    Science.gov (United States)

    Kernodle, J.M.; McAda, D.P.; Thorn, C.R.

    1995-01-01

    This report describes a three-dimensional finite-difference ground-water-flow model of the Santa Fe Group aquifer system in the Albuquerque Basin, which comprises the Santa Fe Group (late Oligocene to middle Pleistocene age) and overlying valley and basin-fill deposits (Pleistocene to Holocene age). The model is designed to be flexible and adaptive to new geologic and hydrologic information as it becomes available by using a geographic information system as a data-base manager to interface with the model. The aquifer system was defined and quantified in the model consistent with the current (July 1994) understanding of the structural and geohydrologic framework of the basin. Rather than putting the model through a rigorous calibration process, dis- crepancies between simulated and measured responses in hydraulic head were taken to indicate that the understanding of a local part of the aquifer system was incomplete or incorrect. The model simulates ground-water flow over an area of about 2,400 square miles to a depth of 1,730 to about 2,020 feet below the water table with 244 rows, 178 columns, and 11 layers. Of the 477,752 cells in the model, 310,376 are active. The top four model layers approximate the 80-foot thickness of alluvium in the incised and refilled valley of the Rio Grande to provide detail of the effect of ground-water withdrawals on the surface- water system. Away from the valley these four layers represent the interval within the Santa Fe Group aquifer system between the com- puted predevelopment water table and a level 80 feet below the grade of the Rio Grande. The simulations include initial condi- tions (steady-state), the 1901-1994 historical period, and four possible ground-water withdrawal scenarios from 1994 to 2020. The model indicates that for the year ending in March 1994, net surface-water loss in the basin resulting from the City of Albuquerque's ground-water withdrawal totaled about 53,000 acre- feet. The balance of the about 123

  4. Corrosion of dissimilar metal crevices in simulated concentrated ground water solutions at elevated temperature

    Energy Technology Data Exchange (ETDEWEB)

    Ikeda, B.M.; Quinn, M.J

    2003-01-01

    The disposal of high-level nuclear waste in the Yucca Mountain, Nevada is under consideration by the US Department of Energy. The proposed facility will be located in the unsaturated zone approximately 300 m below the surface and 300 m above the water table. The proposed waste container consists of an outer corrosion-resistant Alloy 22 shell surrounding a 316 NG stainless steel structural inner container that encapsulates the used nuclear fuel waste. A titanium drip shield is proposed to protect the waste container from ground water seepage arid rock-fail. A cycle of dripping/evaporation could result in the generation of concentrated aggressive solutions, which could contact the waste container. The waste container material could be susceptible to crevice corrosion from such solutions. The experiments described in this report support the modeling of waste package degradation processes. The intent was to provide parameter values that are required to model crevice corrosion chemistry, as it relates to hydrogen pick-up, and stress corrosion cracking for selected candidate waste package materials. The purpose of the experiments was to study the crevice corrosion behavior of various candidate materials under near freely corroding conditions and to determine the pH developed in crevice solutions. Experimental results of crevice corrosion of dissimilar metal pairs (Alloy 22, Grade-7 and -16 titanium and 316 stainless steel) immersed in a simulated concentrated ground water at {approx}90{sup o}C are reported. The corrosion potential was measured during exposure periods of between 330 and 630 h. Following the experiments, the pH of the crevice solution was measured. The results indicate that a limited degree of crevice acidification occurred during the experiment. The values for corrosion potential suggest that crevice corrosion may have initiated. The total corrosion was limited, with little visible evidence for crevice corrosion being observed on the sample coupon faces

  5. Study on the System Design of a Solar Assisted Ground Heat Pump System Using Dynamic Simulation

    Directory of Open Access Journals (Sweden)

    Min Gyung Yu

    2016-04-01

    Full Text Available Recently, the use of hybrid systems using multiple heat sources in buildings to ensure a stable energy supply and improve the system performance has gained attention. Among them, a heat pump system using both solar and ground heat was developed and various system configurations have been introduced. However, establishing a suitable design method for the solar-assisted ground heat pump (SAGHP system including a thermal storage tank is complicated and there are few quantitative studies on the detailed system configurations. Therefore, this study developed three SAGHP system design methods considering the design factors focused on the thermal storage tank. Using dynamic energy simulation code (TRNSYS 17, individual performance analysis models were developed and long-term quantitative analysis was carried out to suggest optimum design and operation methods. As a result, it was found that SYSTEM 2 which is a hybrid system with heat storage tank for only a solar system showed the highest average heat source temperature of 14.81 °C, which is about 11 °C higher than minimum temperature in SYSTEM 3. Furthermore, the best coefficient of performance (COP values of heat pump and system were 5.23 and 4.32 in SYSYEM 2, using high and stable solar heat from a thermal storage tank. Moreover, this paper considered five different geographical and climatic locations and the SAGHP system worked efficiently in having high solar radiation and cool climate zones and the system COP was 4.51 in the case of Winnipeg (Canada where the highest heating demand is required.

  6. Numerical simulation of the process of geothermal low-potential ground energy extraction in Perm region (Russia

    Directory of Open Access Journals (Sweden)

    Ponomaryov Andrey

    2016-01-01

    Full Text Available The aim of our research is to study the interaction of energy foundations with the ground mass and to develop methods for their construction on the example of the city of Perm. Field studies of ground were carried out in a specially chosen pilot site to determine temperature distribution in the ground mass, change of ground-water level and physical-mechanical and thermal-physical characteristics of the ground mass. The diagrams of depth temperature distribution in the ground and its seasonal variations were obtained on the results of monitoring, and also the average groundwater level. To carry out numerical simulation, software-complex “GeoStudio” was selected. Its basic differential equation is the fundamental heat conduction equation with an internal heat source. The purpose of the numerical simulation was quantitative evaluation of the thermal energy extracted from different energy foundations under soil conditions in the city of Perm. By results of the spent numerical experiments the equations of regress and nomographs dependences of size of received thermal energy on geometrical parameters of the projected power bases to hydro-geological and climatic conditions of the Perm region are constructed.

  7. Effect of Ground Waste Concrete Powder on Cement Properties

    Directory of Open Access Journals (Sweden)

    Xianwei Ma

    2013-01-01

    Full Text Available The paste/mortar attached to the recycled aggregate decreases the quality of the aggregate and needs to be stripped. The stripped paste/mortar is roughly 20% to 50% in waste concrete, but relevant research is very limited. In this paper, the effects of ground waste concrete (GWC powder, coming from the attached paste/mortar, on water demand for normal consistency, setting time, fluidity, and compressive strength of cement were analyzed. The results show that the 20% of GWC powder (by the mass of binder has little effect on the above properties and can prepare C20 concrete; when the sand made by waste red clay brick (WRB replaces 20% of river sand, the strength of the concrete is increased by 17% compared with that without WRB sand.

  8. Observational Selection Effects with Ground-based Gravitational Wave Detectors

    Science.gov (United States)

    Chen, Hsin-Yu; Essick, Reed; Vitale, Salvatore; Holz, Daniel; Katsavounidis, Erik

    2017-01-01

    Ground-based interferometers are not perfectly all-sky instruments, and it is important to account for their behavior when considering the distribution of detected events. In particular, the LIGO detectors are most sensitive to sources above North America and the Indian Ocean and, as the Earth rotates, the sensitive regions are swept across the sky. However, because the detectors do not acquire data uniformly over time, there is a net bias on detectable sources' right ascensions. Both LIGO detectors preferentially collect data during their local night; it is more than twice as likely to be local midnight than noon when both detectors are operating. We discuss these selection effects and how they impact LIGO's observations and electromagnetic follow-up. These effects can inform electromagnetic follow-up activities and optimization, including the possibility of directing observations even before gravitational-wave events occur.

  9. Detectability of underground electrical cables junction with a ground penetrating radar: electromagnetic simulation and experimental measurements

    Science.gov (United States)

    Liu, Xiang; serhir, mohammed; kameni, abelin; lambert, marc; pichon, lionel

    2016-04-01

    For a company like Electricity De France (EDF), being able to detect accurately using non-destructive methods the position of the buried junction between two underground cables is a crucial issue. The junction is the linking part where most maintenance operations are carried out. The challenge of this work is to conduct a feasibility study to confirm or deny the relevance of Ground Penetrating Radar (GPR) to detect these buried junctions in their actual environment against clutter. Indeed, the cables are buried in inhomogeneous medium at around 80cm deep. To do this, the study is conducted in a numerical environment. We use the 3D simulation software CST MWS to model a GPR scenario. In this simulation, we place the already optimized bowtie antennas operating in the frequency band [0.5 GHz - 3 GHz] in front of wet soil (dispersive) and dry soil where the underground cable is placed at 80cm deep. We collect the amplitude and phase of the reflected waves in order to detect the contrast provoked by the geometric dimensions variation of the cable [1] (diameter of the cable is 48mm and the diameter of the junction 74mm). The use of an ultra-wideband antenna is necessary to reconcile resolution and penetration of electromagnetic waves in the medium to be characterized. We focus on the performance of the GPR method according to the characteristics of the surrounding medium in which the electric cables are buried, the polarization of the Tx and Rx antennas. The experimental measurement collected in the EDF site will be presented. The measured data are processed using the clutter reduction method based on digital filtering [2]. We aim at showing that using the developed bowtie antennas that the GPR technique is well adapted for the cable junction localization even in cluttered environment. References [1] D. J. Daniels, "Surface-Penetrating Radar", London, IEE 1996. [2] Potin, D.; Duflos, E.; Vanheeghe, P., "Landmines Ground-Penetrating Radar Signal Enhancement by Digital

  10. Dynamic Response and Ground-Motion Effects of Building Clusters During Large Earthquakes

    Science.gov (United States)

    Isbiliroglu, Y. D.; Taborda, R.; Bielak, J.

    2012-12-01

    The objective of this study is to analyze the response of building clusters during earthquakes, the effect that they have on the ground motion, and how individual buildings interact with the surrounding soil and with each other. We conduct a series of large-scale, physics-based simulations that synthesize the earthquake source and the response of entire building inventories. The configuration of the clusters, defined by the total number of buildings, their number of stories, dynamic properties, and spatial distribution and separation, is varied for each simulation. In order to perform these simulations efficiently while recurrently modifying these characteristics without redoing the entire "source to building structure" simulation every time, we use the Domain Reduction Method (DRM). The DRM is a modular two-step finite-element methodology for modeling wave propagation problems in regions with localized features. It allows one to store and reuse the background motion excitation of subdomains without loss of information. Buildings are included in the second step of the DRM. Each building is represented by a block model composed of additional finite-elements in full contact with the ground. These models are adjusted to emulate the general geometric and dynamic properties of real buildings. We conduct our study in the greater Los Angeles basin, using the main shock of the 1994 Northridge earthquake for frequencies up to 5Hz. In the first step of the DRM we use a domain of 82 km x 82 km x 41 km. Then, for the second step, we use a smaller sub-domain of 5.12 km x 5.12 km x 1.28 km, with the buildings. The results suggest that site-city interaction effects are more prominent for building clusters in soft-soil areas. These effects consist in changes in the amplitude of the ground motion and dynamic response of the buildings. The simulations are done using Hercules, the parallel octree-based finite-element earthquake simulator developed by the Quake Group at Carnegie

  11. Measurement of effectiveness for training simulations

    NARCIS (Netherlands)

    Korteling, J.E.; Oprins, E.A.P.B.; Kallen, V.L.

    2013-01-01

    This paper presents and discusses experimental designs, measures, and measurement methods for determining the effectiveness of training simulators. First, we describe experimental designs in which training effects of training simulators are compared to those of conventional training. Next, the most

  12. Computer simulation models relevant to ground water contamination from EOR or other fluids - state-of-the-art

    Energy Technology Data Exchange (ETDEWEB)

    Kayser, M.B.; Collins, A.G.

    1986-03-01

    Ground water contamination is a serious national problem. The use of computers to simulate the behavior of fluids in the subsurface has proliferated extensively over the last decade. Numerical models are being used to solve water supply problems, various kinds of enertgy production problems, and ground water contamination problems. Modeling techniques have progressed to the point that their accuracy is only limited by the modeller's ability to describe the reservoir in question and the heterogeneities therein. Pursuant to the Task and Milestone Update of Project BE3A, this report summarizes the state of the art of computer simulation models relevant to contamination of ground water by enhanced oil recovery (EOR) chemicals and/or waste fluids. 150 refs., 6 tabs.

  13. Simulation of ground-water flow in the vicinity of Hyde Park landfill, Niagara Falls, New York

    Science.gov (United States)

    Maslia, M.L.; Johnston, R.H.

    1982-01-01

    The Hyde Park landfill is a 15-acre chemical waste disposal site located north of Niagara Falls, New York. Underlying the site in descending order are: (1) low permeability glacial till, (2) a moderately permeable fractured rock aquifer--the Lockport Dolomite, and (3) a low permeability unit--the Rochester Shale. The site is bounded on three sides by ground-water drains; the Niagara River Gorge, the Niagara Power Project canal, and the power project conduits. A finite element model was used to simulate ground-water flow along an east-west section through the Hyde Park site (from the power project conduits to the Niagara Gorge). Steady-state conditions were simulated with an average annual recharge rate of 5 inches per year. The calibrated model simulated measured water levels within 5 feet in the glacial till and upper unit of the Lockport Dolomite and approximated the configuration of the water table. Based on simulation, ground-water flow near the Hyde Park site can be summarized as follows: 1. Specific discharge (Darcy velocity) ranges from about 0.01 to 0.1 foot per day in the upper unit of the Lockport Dolomite to less than 0.00001 foot per day in the Rochester Shale. Real velocities are highest in the upper unit of the Lockport, ranging from about 1.5 to 4.8 feet per day. 2. A ground-water divide exists east of the landfill, indicating that all ground water originating near or flowing beneath the landfill will flow toward and discharge in the gorge. 3. The zone of highest velocities (and presumably greatest potential for transporting chemical contaminants) includes the upper unit of the Lockport and part of the lower unit of the Lockport Dolomite between the landfill and the gorge. The time required for ground water to move from the landfill to the gorge in the Lockport Dolomite is estimated to be 5 to 7 years.

  14. High Re wall-modeled LES of aircraft wake vortices in ground effect

    Science.gov (United States)

    Thiry, Olivier; Winckelmans, Gregoire; Duponcheel, Matthieu

    2014-11-01

    We have been able to perform wall-resolved LES, using a fourth order code, to simulate (aircraft) wake vortices interacting with the ground, also with cross or head winds, up to Reynolds numbers of the order of Re = Γ / ν = 2 ×104 . The present work aims at providing higher Re simulations, and also simulations with rough walls (e.g., grass), through the use of LES with near wall modeling. Various types of models are compared: point-wise and averaged algebraic models, and two-layers models. When using averaged models, the averaging methodology is of importance, since there is essentially no homogeneous direction in the case of wake vortices in ground effects. Uni- and multi-directional averaging strategies, with and without additional time averaging will be considered. When two-layer models are used, a RANS sub-layer will be compared to a simpler approach based on simplified turbulent boundary layer equations. The approaches are first validated on simpler flows, channel flow or wake flow, for which reference wall-resolved LES or DNS results are available. Research fellow (Ph.D. student) at the F.R.S.-FNRS (Belgium)

  15. Low-speed aerodynamic characteristics of a powered NASP-like configuration in ground effect

    Science.gov (United States)

    Gatlin, Gregory M.

    1989-01-01

    Results are presented on the low-speed aerodynamic characteristics of a simplified NASP (for National Aerospace Plane Program)-like configuration, obtained in the NASA-Langley 14-by-22-foot subsonic tunnel. The model consisted of a triangular wedge forebody, a rectangular midsection housing the propulsion simulation system, and a rectangular wedge aftbody; it also included a delta wing, exhaust flow deflectors, and aftbody fences. Flow visualization was obtained by injecting water into the engine simulator inlets and using a laser light sheet to illuminate the resulting exhaust flow. It was found that power-on ground effects for NASP-like configuration can be substantial; these effects can be reduced by increasing the angle-of-attack to the value of the aftbody ramp angle. Power-on lift losses in ground effect increased with increasing thrust, but could be reduced by the addition of a delta wing to the configuration. Power-on lift losses also increased with use of aftbody fences.

  16. Simulated forecasts for primordial B-mode searches in ground-based experiments

    CERN Document Server

    Alonso, David; Naess, Sigurd; Thorne, Ben

    2016-01-01

    Detecting the imprint of inflationary gravitational waves on the $B$-mode polarization of the Cosmic Microwave Background (CMB) is one of the main science cases for current and next-generation CMB experiments. In this work we explore some of the challenges that ground-based facilities will have to face in order to carry out this measurement in the presence of Galactic foregrounds and correlated atmospheric noise. We present forecasts for Stage-3 (S3) and planned Stage-4 (S4) experiments based on the analysis of simulated sky maps using a map-based Bayesian foreground cleaning method. Our results thus consistently propagate the uncertainties on foreground parameters such as spatially-varying spectral indices, as well as the bias on the measured tensor-to-scalar ratio $r$ caused by an incorrect modelling of the foregrounds. We find that S3 and S4-like experiments should be able to put constraints on $r$ of the order $\\sigma(r)=(0.5-1.0)\\times10^{-2}$ and $\\sigma(r)=(0.5-1.0)\\times10^{-3}$ respectively, assuming...

  17. Dynamics Simulation Analysis of Solar Array Ground Deployment and Locking%太阳翼地面展开锁定的动力学仿真分析

    Institute of Scientific and Technical Information of China (English)

    王晛; 陈天智; 柴洪友

    2011-01-01

    A simulation model for solar array ground deployment and locking is proposed with the combination of ADAMS and PATRAN/NASTRAN, based on the ADAMS's function of dynamics analysis of the flexible body. The flexibility of yoke and panels is considered at the beginning of the deployment. Concerning all the ground factors, the ground deployment and locking process is simulated constantly, and the dynamics properties, such as the impact load on solar array drive assembly, are obtained. Ground experiment has demonstrated effectiveness of the proposed approach. Then,the simulation results of solar array space deployment and locking are presented.Finally, the effects of the air resistance, the friction of the suspension system and other factors on the impact load are investigated with the simulation model.%利用ADAMS软件的柔体动力学计算功能,将ADAMS和PATRAN/NASTRAN软件联合,建立太阳翼地面展开及锁定仿真模型,从太阳翼展开初始就考虑连接架和基板的弹性,以及地面各影响因素的影响,对太阳翼地面展开锁定过程进行连续的仿真计算,得到了对驱动机构的冲击载荷等动力学性能.分析方法得到了试验的验证.其后,给出了太阳翼空间展开锁定仿真结果.最后,利用仿真模型,分析了空气阻力、吊挂装置摩擦阻力等因素对太阳翼地面展开及锁定冲击载荷的影响.

  18. Observational Selection Effects with Ground-based Gravitational Wave Detectors

    CERN Document Server

    Chen, Hsin-Yu; Vitale, Salvatore; Holz, Daniel E; Katsavounidis, Erik

    2016-01-01

    Ground-based interferometers are not perfectly all-sky instruments, and it is important to account for their behavior when considering the distribution of detected events. In particular, the LIGO detectors are most sensitive to sources above North America and the Indian Ocean and, as the Earth rotates, the sensitive regions are swept across the sky. However, because the detectors do not acquire data uniformly over time, there is a net bias on detectable sources' right ascensions. Both LIGO detectors preferentially collect data during their local night; it is more than twice as likely to be local midnight than noon when both detectors are operating. We discuss these selection effects and how they impact LIGO's observations and electromagnetic follow-up. Beyond galactic foregrounds associated with seasonal variations, we find that equatorial observatories can access over $80\\%$ of the localization probability, while mid-latitudes will access closer to $70\\%$. Facilities located near the two LIGO sites can obser...

  19. Comparing Monte Carlo methods for finding ground states of Ising spin glasses: Population annealing, simulated annealing, and parallel tempering

    Science.gov (United States)

    Wang, Wenlong; Machta, Jonathan; Katzgraber, Helmut G.

    2015-07-01

    Population annealing is a Monte Carlo algorithm that marries features from simulated-annealing and parallel-tempering Monte Carlo. As such, it is ideal to overcome large energy barriers in the free-energy landscape while minimizing a Hamiltonian. Thus, population-annealing Monte Carlo can be used as a heuristic to solve combinatorial optimization problems. We illustrate the capabilities of population-annealing Monte Carlo by computing ground states of the three-dimensional Ising spin glass with Gaussian disorder, while comparing to simulated-annealing and parallel-tempering Monte Carlo. Our results suggest that population annealing Monte Carlo is significantly more efficient than simulated annealing but comparable to parallel-tempering Monte Carlo for finding spin-glass ground states.

  20. Comparing Monte Carlo methods for finding ground states of Ising spin glasses: Population annealing, simulated annealing, and parallel tempering.

    Science.gov (United States)

    Wang, Wenlong; Machta, Jonathan; Katzgraber, Helmut G

    2015-07-01

    Population annealing is a Monte Carlo algorithm that marries features from simulated-annealing and parallel-tempering Monte Carlo. As such, it is ideal to overcome large energy barriers in the free-energy landscape while minimizing a Hamiltonian. Thus, population-annealing Monte Carlo can be used as a heuristic to solve combinatorial optimization problems. We illustrate the capabilities of population-annealing Monte Carlo by computing ground states of the three-dimensional Ising spin glass with Gaussian disorder, while comparing to simulated-annealing and parallel-tempering Monte Carlo. Our results suggest that population annealing Monte Carlo is significantly more efficient than simulated annealing but comparable to parallel-tempering Monte Carlo for finding spin-glass ground states.

  1. Dynamical response of the Galileo Galilei on the ground rotor to test the equivalence principle: Theory, simulation, and experiment. II. The rejection of common mode forces

    Science.gov (United States)

    Comandi, G. L.; Toncelli, R.; Chiofalo, M. L.; Bramanti, D.; Nobili, A. M.

    2006-03-01

    "Galileo Galilei on the ground" (GGG) is a fast rotating differential accelerometer designed to test the equivalence principle (EP). Its sensitivity to differential effects, such as the effect of an EP violation, depends crucially on the capability of the accelerometer to reject all effects acting in common mode. By applying the theoretical and simulation methods reported in Part I of this work, and tested therein against experimental data, we predict the occurrence of an enhanced common mode rejection of the GGG accelerometer. We demonstrate that the best rejection of common mode disturbances can be tuned in a controlled way by varying the spin frequency of the GGG rotor.

  2. Geohydrology and simulation of ground-water flow in the Red Clay Creek Basin, Chester County, Pennsylvania, and New Castle County, Delaware

    Science.gov (United States)

    Vogel, K.L.; Reif, A.G.

    1993-01-01

    The 54-square-mile Red Clay Creek Basin, located in the lower Delaware River Basin, is underlain primarily by metamorphic rocks that range from Precambrian to Lower Paleozoic in age. Ground water flows through secondary openings in fractured crystalline rock and through primary openings below the water table in the overlying saprolite. Secondary porosity and permeability vary with hydrogeologic unit, topographic setting, and depth. Thirty-nine percent of the water-bearing zones are encountered within 100 feet of the land surface, and 79 percent are within 200 feet. The fractured crystalline rock and overlying saprolite act as a single aquifer under unconfined conditions. The water table is a subdued replica of the land surface. Local ground-water flow systems predominate in the basin, and natural ground-water discharge is to streams, comprising 62 to 71 percent of streamflow. Water budgets for 1988-90 for the 45-square-mile effective drainage area above the Woodale, Del., streamflow-measurement station show that annual precipitation ranged from 43.59 to 59.14 inches and averaged 49.81 inches, annual streamflow ranged from 15.35 to 26.33 inches and averaged 20.24 inches, and annual evapotranspiration ranged from 27.87 to 30.43 inches and averaged 28.98 inches. The crystalline rocks of the Red Clay Creek Basin were simulated two-dimensionally as a single aquifer under unconfined conditions. The model was calibrated for short-term steady-state conditions on November 2, 1990. Recharge was 8.32 inches per year. Values of aquifer hydraulic conductivity in hillside topographic settings ranged from 0.07 to 2.60 feet per day. Values of streambed hydraulic conductivity ranged from 0.08 to 26.0 feet per day. Prior to simulations where ground-water development was increased, the calibrated steady-state model was modified to approximate long-term average conditions in the basin. Base flow of 11.98 inches per year and a ground-water evapotranspiration rate of 2.17 inches per

  3. Modeling earthquake ground motion with an earthquake simulation program (EMPSYN) that utilizes empirical Green's functions

    Energy Technology Data Exchange (ETDEWEB)

    Hutchings, L.

    1992-01-01

    This report outlines a method of using empirical Green's functions in an earthquake simulation program EMPSYN that provides realistic seismograms from potential earthquakes. The theory for using empirical Green's functions is developed, implementation of the theory in EMPSYN is outlined, and an example is presented where EMPSYN is used to synthesize observed records from the 1971 San Fernando earthquake. To provide useful synthetic ground motion data from potential earthquakes, synthetic seismograms should model frequencies from 0.5 to 15.0 Hz, the full wave-train energy distribution, and absolute amplitudes. However, high-frequency arrivals are stochastically dependent upon the inhomogeneous geologic structure and irregular fault rupture. The fault rupture can be modeled, but the stochastic nature of faulting is largely an unknown factor in the earthquake process. The effect of inhomogeneous geology can readily be incorporated into synthetic seismograms by using small earthquakes to obtain empirical Green's functions. Small earthquakes with source corner frequencies higher than the site recording limit f{sub max}, or much higher than the frequency of interest, effectively have impulsive point-fault dislocation sources, and their recordings are used as empirical Green's functions. Since empirical Green's functions are actual recordings at a site, they include the effects on seismic waves from all geologic inhomogeneities and include all recordable frequencies, absolute amplitudes, and all phases. They scale only in amplitude with differences in seismic moment. They can provide nearly the exact integrand to the representation relation. Furthermore, since their source events have spatial extent, they can be summed to simulate fault rupture without loss of information, thereby potentially computing the exact representation relation for an extended source earthquake.

  4. Amplification of seismic ground motion in the Tunis basin: Numerical BEM simulations vs experimental evidences

    CERN Document Server

    Kham, Marc; Bouden-Romdhane, Nejla

    2013-01-01

    This paper aims at the analysis of seismic wave amplification in a deep alluvial basin in the city of Tunis in Tunisia. This sedimentary basin is 3000m wide and 350m deep. Since the seismic hazard is significant in this area, the depth of the basin and the strong impedance ratio raise the need for an accurate estimation of seismic motion amplification. Various experimental investigations were performed in previous studies to characterize site effects. The Boundary Element Method is considered herein to assess the parameter sensitivity of the amplification process and analyse the prevailing phenomena. The various frequencies of maximum amplification are correctly estimated by the BEM simulations. The maximum amplification level observed in the field is also well retrieved by the numerical simulations but, due to the sensitivity of the location of maximum amplification in space, the overall maximum amplification has to be considered. The influence of the wave-field incidence and material damping is also discuss...

  5. Three-dimensional ground-motion simulations of earthquakes for the Hanford area, Washington

    Science.gov (United States)

    Frankel, Arthur; Thorne, Paul; Rohay, Alan

    2014-01-01

    This report describes the results of ground-motion simulations of earthquakes using three-dimensional (3D) and one-dimensional (1D) crustal models conducted for the probabilistic seismic hazard assessment (PSHA) of the Hanford facility, Washington, under the Senior Seismic Hazard Analysis Committee (SSHAC) guidelines. The first portion of this report demonstrates that the 3D seismic velocity model for the area produces synthetic seismograms with characteristics (spectral response values, duration) that better match those of the observed recordings of local earthquakes, compared to a 1D model with horizontal layers. The second part of the report compares the response spectra of synthetics from 3D and 1D models for moment magnitude (M) 6.6–6.8 earthquakes on three nearby faults and for a dipping plane wave source meant to approximate regional S-waves from a Cascadia great earthquake. The 1D models are specific to each site used for the PSHA. The use of the 3D model produces spectral response accelerations at periods of 0.5–2.0 seconds as much as a factor of 4.5 greater than those from the 1D models for the crustal fault sources. The spectral accelerations of the 3D synthetics for the Cascadia plane-wave source are as much as a factor of 9 greater than those from the 1D models. The differences between the spectral accelerations for the 3D and 1D models are most pronounced for sites with thicker supra-basalt sediments and for stations with earthquakes on the Rattlesnake Hills fault and for the Cascadia plane-wave source.

  6. Fiber-coupling efficiency simulation of Gaussian Schell Model laser in space-to-ground optical communication link

    Science.gov (United States)

    Tan, Liying; Li, Mengnan; Wu, Jiajie; Ma, Jing; Yang, Qingbo

    2015-08-01

    In practice, due to reasons related to the laser device and the inevitable error of the processing technique, a laser source emitted from a communication terminal is partially coherent, which is represented by the Gaussian Schell Model (GSM). In a space-to-ground optical communication link, the cross-spectral density function, based on the Gaussian Model in previous research, is replaced by GSM; thus, the fiber-coupling efficiency equation of the GSM laser source is deduced. The GSM equation presents the effects of the source coherent parameter ζ and the zenith angle θ on the fiber-coupling efficiency, which were not included previously. The effects on the fiber-coupling efficiency are numerically simulated and analyzed. The results manifest that the fiber-coupling efficiency invariably degrades with increasing ζ or θ. The hope of this work is to improve the redundancy design of fiber-coupling receiver systems by analyzing the fiber-coupling efficiency with the source coherent parameter.

  7. Status of the Correlation Process of the V-HAB Simulation with Ground Tests and ISS Telemetry Data

    Science.gov (United States)

    Ploetner, Peter; Anderson, Molly S.; Czupalla, Markus; Ewert, Micahel K.; Roth, Christof Martin; Zhulov, Anton

    2012-01-01

    The Virtual Habitat (V-HAB) is a dynamic Life Support System (LSS) simulation, created to investigate future human spaceflight missions. V-HAB provides the capability to optimize LSS during early design phases. Furthermore, it allows simulation of worst case scenarios which cannot be tested in reality. In a nutshell, the tool allows the testing of LSS robustness by means of computer simulations. V-HAB is a modular simulation consisting of a: 1. Closed Environment Module 2. Crew Module 3. Biological Module 4. Physio-Chemical Module The focus of the paper will be the correlation and validation of V-HAB against ground test and flight data. The ECLSS technologies (CDRA, CCAA, OGA, etc.) are correlated one by one against available ground test data, which is briefly described in this paper. The technology models in V-HAB are merged to simulate the ISS ECLSS. This simulation is correlated against telemetry data from the ISS, including the water recovery system and the air revitalization system. Finally, an analysis of the results is included in this paper.

  8. The SCEC-USGS Dynamic Earthquake Rupture Code Comparison Exercise - Simulations of Large Earthquakes and Strong Ground Motions

    Science.gov (United States)

    Harris, R.

    2015-12-01

    I summarize the progress by the Southern California Earthquake Center (SCEC) and U.S. Geological Survey (USGS) Dynamic Rupture Code Comparison Group, that examines if the results produced by multiple researchers' earthquake simulation codes agree with each other when computing benchmark scenarios of dynamically propagating earthquake ruptures. These types of computer simulations have no analytical solutions with which to compare, so we use qualitative and quantitative inter-code comparisons to check if they are operating satisfactorily. To date we have tested the codes against benchmark exercises that incorporate a range of features, including single and multiple planar faults, single rough faults, slip-weakening, rate-state, and thermal pressurization friction, elastic and visco-plastic off-fault behavior, complete stress drops that lead to extreme ground motion, heterogeneous initial stresses, and heterogeneous material (rock) structure. Our goal is reproducibility, and we focus on the types of earthquake-simulation assumptions that have been or will be used in basic studies of earthquake physics, or in direct applications to specific earthquake hazard problems. Our group's goals are to make sure that when our earthquake-simulation codes simulate these types of earthquake scenarios along with the resulting simulated strong ground shaking, that the codes are operating as expected. For more introductory information about our group and our work, please see our group's overview papers, Harris et al., Seismological Research Letters, 2009, and Harris et al., Seismological Research Letters, 2011, along with our website, scecdata.usc.edu/cvws.

  9. Research on the acquisition and tracking simulation system of light beacon in satellite-ground optical communications

    Institute of Scientific and Technical Information of China (English)

    ZUO Tao; AI Yong; HUANG Hai-bo; SU Gui-bo

    2010-01-01

    @@ The study on the acquisition and tracking simulation system in satellite-ground optical communications is presented here.By applying global positioning system(GPS)coordinate calculation,the time needed in initial acquisition of light beacon can be reduced largely.Smith predictor is applied to compensate the mechanical hysteresis of tracking system and to improve the dynamic performance of the system.Tracking experiments over a i 6 km distance on the ground are conducted to verify the tracking of light beacon in satellite-ground optical communications.The standard deviation of horizontal coordinates is 35.3568 μrad and the maximum offset is 209.3675 μrad in stable tracking.

  10. Geohydrology, Geochemistry, and Ground-Water Simulation-Optimization of the Central and West Coast Basins, Los Angeles County, California

    Science.gov (United States)

    Reichard, Eric G.; Land, Michael; Crawford, Steven M.; Johnson, Tyler D.; Everett, Rhett; Kulshan, Trayle V.; Ponti, Daniel J.; Halford, Keith L.; Johnson, Theodore A.; Paybins, Katherine S.; Nishikawa, Tracy

    2003-01-01

    Historical ground-water development of the Central and West Coast Basins in Los Angeles County, California through the first half of the 20th century caused large water-level declines and induced seawater intrusion. Because of this, the basins were adjudicated and numerous ground-water management activities were implemented, including increased water spreading, construction of injection barriers, increased delivery of imported water, and increased use of reclaimed water. In order to improve the scientific basis for these water management activities, an extensive data collection program was undertaken, geohydrological and geochemical analyses were conducted, and ground-water flow simulation and optimization models were developed. In this project, extensive hydraulic, geologic, and chemical data were collected from new multiple-well monitoring sites. On the basis of these data and data compiled and collected from existing wells, the regional geohydrologic framework was characterized. For the purposes of modeling, the three-dimensional aquifer system was divided into four aquifer systems?the Recent, Lakewood, Upper San Pedro, and Lower San Pedro aquifer systems. Most pumpage in the two basins is from the Upper San Pedro aquifer system. Assessment of the three-dimensional geochemical data provides insight into the sources of recharge and the movement and age of ground water in the study area. Major-ion data indicate the chemical character of water containing less than 500 mg/L dissolved solids generally grades from calcium-bicarbonate/sulfate to sodium bicarbonate. Sodium-chloride water, high in dissolved solids, is present in wells near the coast. Stable isotopes of oxygen and hydrogen provide information on sources of recharge to the basin, including imported water and water originating in the San Fernando Valley, San Gabriel Valley, and the coastal plain and surrounding hills. Tritium and carbon-14 data provide information on relative ground-water ages. Water with

  11. Launch and Landing Effects Ground Operations (LLEGO) Model

    Science.gov (United States)

    2008-01-01

    LLEGO is a model for understanding recurring launch and landing operations costs at Kennedy Space Center for human space flight. Launch and landing operations are often referred to as ground processing, or ground operations. Currently, this function is specific to the ground operations for the Space Shuttle Space Transportation System within the Space Shuttle Program. The Constellation system to follow the Space Shuttle consists of the crewed Orion spacecraft atop an Ares I launch vehicle and the uncrewed Ares V cargo launch vehicle. The Constellation flight and ground systems build upon many elements of the existing Shuttle flight and ground hardware, as well as upon existing organizations and processes. In turn, the LLEGO model builds upon past ground operations research, modeling, data, and experience in estimating for future programs. Rather than to simply provide estimates, the LLEGO model s main purpose is to improve expenses by relating complex relationships among functions (ground operations contractor, subcontractors, civil service technical, center management, operations, etc.) to tangible drivers. Drivers include flight system complexity and reliability, as well as operations and supply chain management processes and technology. Together these factors define the operability and potential improvements for any future system, from the most direct to the least direct expenses.

  12. Orientation effect on ground motion measurement for Mexican subduction earthquakes

    Institute of Scientific and Technical Information of China (English)

    H.P Hong; A. Pozos-Estrada; R. Gomez

    2009-01-01

    The existence of the principal directions of the ground motion based on Arias intensity is well-known. These principal directions do not necessarily coincide with the orientations of recording sensors or with the orientations along which the ground motion parameters such as the peak ground acceleration and the pseudo-spectral acceleration (PSA) are maximum. This is evidenced by the fact that the maximum PSA at different natural vibration periods for horizontal excitations do not correspond to the same orientation. A recent analysis carried out for California earthquake records suggests that an orientation-dependent ground motion measurement for horizontal excitations can be developed. The main objective of this study is to investigate and provide seismic ground motion measurements in the horizontal plane, including bidirectional horizontal ground motions, for Mexican interplate and inslab earthquake records. Extensive statistical analyses of PSA are conducted for the assessment, The analysis results suggest that similar to the case of California records, the average behavior of the ratio of the PSA to the maximum resulting PSA can be approximated by a quarter of an ellipse in one quadrant; and that the ratio can be considered to be independent of the value of the maximum resulting PSA, earthquake magnitude, earthquake distance and the focal depth. Sets of response ratios and attenuation relationships that can be used to represent a bidirectional horizontal ground motion measurement for Mexican interplate and inslab earthquakes were also developed.

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

  15. Simulation of Ground-Water Flow in the Irwin Basin Aquifer System, Fort Irwin National Training Center, California

    Science.gov (United States)

    Densmore, Jill N.

    2003-01-01

    Ground-water pumping in the Irwin Basin at Fort Irwin National Training Center, California resulted in water-level declines of about 30 feet from 1941 to 1996. Since 1992, artificial recharge from wastewater-effluent infiltration and irrigation-return flow has stabilized water levels, but there is concern that future water demands associated with expansion of the base may cause a resumption of water-level declines. To address these concerns, a ground-water flow model of the Irwin Basin was developed to help better understand the aquifer system, assess the long-term availability and quality of ground water, and evaluate ground-water conditions owing to current pumping and to plan for future water needs at the base. Historical data show that ground-water-level declines in the Irwin Basin between 1941 and 1996, caused the formation of a pumping depression near the pumped wells, and that recharge from the wastewater-treatment facility and disposal area caused the formation of a recharge mound. There have been two periods of water-level recovery in the Irwin Basin since the development of ground water in this basin; these periods coincide with a period of decreased pumpage from the basin and a period of increased recharge of water imported from the Bicycle Basin beginning in 1967 and from the Langford Basin beginning in 1992. Since 1992, artificial recharge has exceeded pumpage in the Irwin Basin and has stabilized water-level declines. A two-layer ground-water flow model was developed to help better understand the aquifer system, assess the long-term availability and quality of ground water, and evaluate ground-water conditions owing to current pumping and to plan for future water needs at the base. Boundary conditions, hydraulic conductivity, altitude of the bottom of the layers, vertical conductance, storage coefficient, recharge, and discharge were determined using existing geohydrologic data. Rates and distribution of recharge and discharge were determined from

  16. Environmental Effect / Impact Assessment of Industrial Effulent on Ground Water

    Directory of Open Access Journals (Sweden)

    Dr. Parmod Kumar

    2013-12-01

    Full Text Available In the present study the aim of investigation is physical and chemical parameters of ground water and soil. By selected Physical and chemical parameters it is found that (1.Biological oxygen demand (BOD and chemical oxygen demand (COD are directly proportional to each other where dissolved oxygen (DO is indirectly proportional to BOD and COD. (2. Total dissolved solids, alkalinity and hardness are significantly higher in pre monsoon and winter season as compared to monsoon season.(3. High values of different parameters of ground water sources indicate the influence of industrial wastes on ground water.

  17. Ground-based simulation of telepresence for materials science experiments. [remote viewing and control of processes aboard Space Station

    Science.gov (United States)

    Johnston, James C.; Rosenthal, Bruce N.; Bonner, Mary JO; Hahn, Richard C.; Herbach, Bruce

    1989-01-01

    A series of ground-based telepresence experiments have been performed to determine the minimum video frame rate and resolution required for the successive performance of materials science experiments in space. The approach used is to simulate transmission between earth and space station with transmission between laboratories on earth. The experiments include isothermal dendrite growth, physical vapor transport, and glass melting. Modifications of existing apparatus, software developed, and the establishment of an inhouse network are reviewed.

  18. Ground-based simulation of telepresence for materials science experiments. [remote viewing and control of processes aboard Space Station

    Science.gov (United States)

    Johnston, James C.; Rosenthal, Bruce N.; Bonner, Mary JO; Hahn, Richard C.; Herbach, Bruce

    1989-01-01

    A series of ground-based telepresence experiments have been performed to determine the minimum video frame rate and resolution required for the successive performance of materials science experiments in space. The approach used is to simulate transmission between earth and space station with transmission between laboratories on earth. The experiments include isothermal dendrite growth, physical vapor transport, and glass melting. Modifications of existing apparatus, software developed, and the establishment of an inhouse network are reviewed.

  19. EFFECT OF GROUND-WATER REMEDIATION ACTIVITIES ON INDIGENOUS MICROFLORA

    Science.gov (United States)

    The United States Environmental Protection Agency (EPA), working with the Interagency DNAPL Consortium, completed an independent evaluation of microbial responses to ground-water remediation technology demonstrations at Launch Pad 34 at Cape Canaveral Air Station in Brevard Count...

  20. Effect of electrode shape on grounding resistances - Part 1

    DEFF Research Database (Denmark)

    Ingeman-Nielsen, Thomas; Tomaskovicova, Sonia; Dahlin, Torleif

    2016-01-01

    . The focus-one protocol is a new method for estimating single electrode grounding resistances by measuring the resistance between a single electrode in an ERT array and all the remaining electrodes connected in parallel. For large arrays, the measured resistance is dominated by the grounding resistance...... of the electrode under test, the focus electrode. We have developed an equivalent circuit model formulation for the resistance measured when applying the focus-one protocol. Our model depends on the individual grounding resistances of the electrodes of the array, the mutual resistances between electrodes......, and the instrument input impedance. Using analytical formulations for the potentials around prolate and oblate spheroidal electrode models (as approximations for rod and plate electrodes), we have investigated the performance and accuracy of the focus-one protocol in estimating single-electrode grounding resistances...

  1. New active-only grounded inductance simulator employing current-mode approach suitable for wide band operation

    Science.gov (United States)

    Yamacli, Serhan; Ozcan, Sadri; Kuntman, Hakan

    2011-08-01

    In this paper, an active-only grounded lossless inductance simulator operating in current-mode is presented. The circuit uses only a current operational amplifier (COA) and an operational transconductance amplifier (OTA). The novelty of the proposed circuit is that it uses a COA instead of a voltage operational amplifier (VOA) to take the wider frequency operation advantage of the current-mode approach. The simulation results obtained through SPICE with 0.5 μm standard CMOS technology verify that the designed circuit can be operated up to 30 MHz, which is much higher than the operation frequency of previously reported inductance simulators utilising VOAs. The inductance value of the presented circuit can be adjusted electronically between 3.9 μH and 37 μH via the biasing current of the OTA. A parallel resonance circuit application is also given validating the operation of the proposed inductance simulator.

  2. Effects of Dielectric Substrates and Ground Planes on Resonance Frequency of Archimedean Spirals.

    Science.gov (United States)

    Hooker, Jerris W; Ramaswamy, Vijaykumar; Arora, Rajendra K; Edison, Arthur S; Brey, William W

    2016-04-01

    Superconducting self-resonant spiral structures are of current interest for applications both in metamaterials and as probe coils for nuclear magnetic resonance (NMR) spectroscopy for high-sensitivity chemical analysis. Accurate spiral models are available in the literature for behavior of a spiral below and up to self-resonance. However, knowledge of the higher modes is also important. We present the relationships between the spiral parameters and the multiple mode frequencies of single sided spirals on dielectric substrates as modeled by method of moments simulation. In the absence of a ground plane, we find that the mode frequency has a linear though not necessarily harmonic dependence on the mode number. The effect of a thick substrate can be approximated by an effective dielectric constant. But when the thickness is less than 20% of the spiral trace width (router - rinner) this approximation is no longer accurate. We have developed a simple empirical formula to predict the higher modes.

  3. Simulator Motion as a Factor in Flight Simulator Training Effectiveness.

    Science.gov (United States)

    Jacobs, Robert S.

    The document reviews the literature concerning the training effectiveness of flight simulators and describes an experiment in progress at the University of Illinois' Institute of Aviation which is an initial attempt to develop systematically the relationship between motion cue fidelity and resultant training effectiveness. The literature review…

  4. Soil moisture characterization of the Valencia anchor station. Ground, aircraft measurements and simulations

    DEFF Research Database (Denmark)

    Lopez-Baeza, E; Antolin, M C; Balling, Jan E.

    2009-01-01

    , soil type, lithology, geology, elevation, slope and vegetation cover conditions. Complementary to the ground measurements, flight operations were performed over this control area using the Helsinki University of Technology TKK Short Skyvan research aircraft which contained onboard a payload constituted...

  5. Algorithmic quantum simulation of memory effects

    Science.gov (United States)

    Alvarez-Rodriguez, U.; Di Candia, R.; Casanova, J.; Sanz, M.; Solano, E.

    2017-02-01

    We propose a method for the algorithmic quantum simulation of memory effects described by integrodifferential evolution equations. It consists in the systematic use of perturbation theory techniques and a Markovian quantum simulator. Our method aims to efficiently simulate both completely positive and nonpositive dynamics without the requirement of engineering non-Markovian environments. Finally, we find that small error bounds can be reached with polynomially scaling resources, evaluated as the time required for the simulation.

  6. Trawling bats exploit an echo-acoustic ground effect

    Directory of Open Access Journals (Sweden)

    Sandor eZsebok

    2013-04-01

    Full Text Available A water surface acts not only as an optic mirror but also as an acoustic mirror. Echolocation calls emitted by bats at low heights above water are reflected away from the bat, and hence the background clutter is reduced. Moreover, targets on the surface create an enhanced echo. Here, we formally quantified the effect of the substrate and target height on both target detection and –discrimination in a combined laboratory and field approach with Myotis daubentonii. In a two-alternative, forced-choice paradigm, the bats had to detect a mealworm and discriminate it from an inedible dummy (20 mm PVC disc. Psychophysical performance was measured as a function of height above either smooth substrates (water or PVC or above a clutter substrate (artificial grass. At low heights above the clutter substrate (10, 20 or 35 cm, the bats’ detection performance was worse than above a smooth substrate. At a height of 50 cm, the substrate structure had no influence on target detection. Above the clutter surface, also target discrimination was significantly impaired with decreasing target height. A detailed analysis of the bats’ echolocation calls during target approach shows that above the clutter substrate, the bats produce calls with significantly higher peak frequency. Flight-path reconstruction revealed that the bats attacked an object from below over water but from above over a clutter substrate.These results are consistent with the hypothesis that trawling bats exploit an echo-acoustic ground effect, in terms of a spatio-temporal integration of direct reflections with indirect reflections from the water surface, to optimize prey detection and –discrimination not only for prey on the water but also for some range above.

  7. Observational Selection Effects with Ground-based Gravitational Wave Detectors

    Science.gov (United States)

    Chen, Hsin-Yu; Essick, Reed; Vitale, Salvatore; Holz, Daniel E.; Katsavounidis, Erik

    2017-01-01

    Ground-based interferometers are not perfect all-sky instruments, and it is important to account for their behavior when considering the distribution of detected events. In particular, the LIGO detectors are most sensitive to sources above North America and the Indian Ocean, and as the Earth rotates, the sensitive regions are swept across the sky. However, because the detectors do not acquire data uniformly over time, there is a net bias on detectable sources’ right ascensions. Both LIGO detectors preferentially collect data during their local night; it is more than twice as likely to be local midnight than noon when both detectors are operating. We discuss these selection effects and how they impact LIGO’s observations and electromagnetic (EM) follow-up. Beyond galactic foregrounds associated with seasonal variations, we find that equatorial observatories can access over 80% of the localization probability, while mid-latitudes will access closer to 70%. Facilities located near the two LIGO sites can observe sources closer to their zenith than their analogs in the south, but the average observation will still be no closer than 44° from zenith. We also find that observatories in Africa or the South Atlantic will wait systematically longer before they can begin observing compared to the rest of the world though, there is a preference for longitudes near the LIGOs. These effects, along with knowledge of the LIGO antenna pattern, can inform EM follow-up activities and optimization, including the possibility of directing observations even before gravitational-wave events occur.

  8. Trawling bats exploit an echo-acoustic ground effect.

    Science.gov (United States)

    Zsebok, Sandor; Kroll, Ferdinand; Heinrich, Melina; Genzel, Daria; Siemers, Björn M; Wiegrebe, Lutz

    2013-01-01

    A water surface acts not only as an optic mirror but also as an acoustic mirror. Echolocation calls emitted by bats at low heights above water are reflected away from the bat, and hence the background clutter is reduced. Moreover, targets on the surface create an enhanced echo. Here, we formally quantified the effect of the surface and target height on both target detection and -discrimination in a combined laboratory and field approach with Myotis daubentonii. In a two-alternative, forced-choice paradigm, the bats had to detect a mealworm and discriminate it from an inedible dummy (20 mm PVC disc). Psychophysical performance was measured as a function of height above either smooth surfaces (water or PVC) or above a clutter surface (artificial grass). At low heights above the clutter surface (10, 20, or 35 cm), the bats' detection performance was worse than above a smooth surface. At a height of 50 cm, the surface structure had no influence on target detection. Above the clutter surface, also target discrimination was significantly impaired with decreasing target height. A detailed analysis of the bats' echolocation calls during target approach shows that above the clutter surface, the bats produce calls with significantly higher peak frequency. Flight-path reconstruction revealed that the bats attacked an target from below over water but from above over a clutter surface. These results are consistent with the hypothesis that trawling bats exploit an echo-acoustic ground effect, in terms of a spatio-temporal integration of direct reflections with indirect reflections from the water surface, to optimize prey detection and -discrimination not only for prey on the water but also for some range above.

  9. Kinematic source model for simulation of near-fault ground motion field using explicit finite element method

    Institute of Scientific and Technical Information of China (English)

    Zhang Xiaozhi; Hu Jinjun; Xie Lili; Wang Haiyun

    2006-01-01

    This paper briefly reviews the characteristics and major processes of the explicit finite element method in modeling the near-fault ground motion field. The emphasis is on the finite element-related problems in the finite fault source modeling. A modified kinematic source model is presented, in which vibration with some high frequency components is introduced into the traditional slip time function to ensure that the source and ground motion include sufficient high frequency components. The model presented is verified through a simple modeling example. It is shown that the predicted near-fault ground motion field exhibits similar characteristics to those observed in strong motion records, such as the hanging wall effect, vertical effect, fling step effect and velocity pulse effect, etc.

  10. Statistical and Probabilistic Extensions to Ground Operations' Discrete Event Simulation Modeling

    Science.gov (United States)

    Trocine, Linda; Cummings, Nicholas H.; Bazzana, Ashley M.; Rychlik, Nathan; LeCroy, Kenneth L.; Cates, Grant R.

    2010-01-01

    NASA's human exploration initiatives will invest in technologies, public/private partnerships, and infrastructure, paving the way for the expansion of human civilization into the solar system and beyond. As it is has been for the past half century, the Kennedy Space Center will be the embarkation point for humankind's journey into the cosmos. Functioning as a next generation space launch complex, Kennedy's launch pads, integration facilities, processing areas, launch and recovery ranges will bustle with the activities of the world's space transportation providers. In developing this complex, KSC teams work through the potential operational scenarios: conducting trade studies, planning and budgeting for expensive and limited resources, and simulating alternative operational schemes. Numerous tools, among them discrete event simulation (DES), were matured during the Constellation Program to conduct such analyses with the purpose of optimizing the launch complex for maximum efficiency, safety, and flexibility while minimizing life cycle costs. Discrete event simulation is a computer-based modeling technique for complex and dynamic systems where the state of the system changes at discrete points in time and whose inputs may include random variables. DES is used to assess timelines and throughput, and to support operability studies and contingency analyses. It is applicable to any space launch campaign and informs decision-makers of the effects of varying numbers of expensive resources and the impact of off nominal scenarios on measures of performance. In order to develop representative DES models, methods were adopted, exploited, or created to extend traditional uses of DES. The Delphi method was adopted and utilized for task duration estimation. DES software was exploited for probabilistic event variation. A roll-up process was used, which was developed to reuse models and model elements in other less - detailed models. The DES team continues to innovate and expand

  11. Aquifer tests and simulation of ground-water flow in Triassic sedimentary rocks near Colmar, Bucks and Montgomery Counties, Pennsylvania

    Science.gov (United States)

    Risser, Dennis W.; Bird, Philip H.

    2003-01-01

    connected to the units stressed by pumping. The best hydraulic connection to the pumped wells was indicated by large drawdown in observation wells that penetrate the water-bearing unit encountered below 400 feet below land surface in wells NP?21 and NP?87. The hydraulic connection between wells NP?21 (or NP?87) and observation wells in the southern area of ground-water contamination near the BAE Systems facility is good because the observation wells probably penetrate this water-bearing unit. A 3-dimensional, finite-difference, groundwater- flow model was used to simulate flow paths and areas contributing recharge to wells for current (2000) conditions of pumping in the Colmar area and for hypothetical situations of pumping suggested by the U.S. Environmental Protection Agency that might be used for remediation. Simulations indicate that under current conditions, ground water in the northern area of contamination near the former Stabilus facility moves to the northwest and discharges mostly to West Branch Neshaminy Creek; in the southern area of contamination near BAE Systems facility, ground water probably moves west and discharges to a tributary ofWest Branch Neshaminy Creek near well NP?21. Model simulations indicate that if NP?21 or NP?87 are pumped at 400 gallons per minute, groundwater recharge is likely captured from the southern area of contamination, but ground-water recharge from the northern area of contamination is less likely to be captured by the pumping. Simulations also indicate that pumping of a new recovery well near BAE Systems facility at 8 gallons per minute and two new recovery wells near the former Stabilus facility at a total of about 30 gallons per minute probably would capture most of the ground-water recharge in the areas where contamination is greatest.

  12. Simulations of Ground-Water Flow, Transport, Age, and Particle Tracking near York, Nebraska, for a Study of Transport of Anthropogenic and Natural Contaminants (TANC) to Public-Supply Wells

    Science.gov (United States)

    Clark, Brian R.; Landon, Matthew K.; Kauffman, Leon J.; Hornberger, George Z.

    2008-01-01

    Contamination of public-supply wells has resulted in public-health threats and negative economic effects for communities that must treat contaminated water or find alternative water supplies. To investigate factors controlling vulnerability of public-supply wells to anthropogenic and natural contaminants using consistent and systematic data collected in a variety of principal aquifer settings in the United States, a study of Transport of Anthropogenic and Natural Contaminants to public-supply wells was begun in 2001 as part of the U.S. Geological Survey National Water-Quality Assessment Program. The area simulated by the ground-water flow model described in this report was selected for a study of processes influencing contaminant distribution and transport along the direction of ground-water flow towards a public-supply well in southeastern York, Nebraska. Ground-water flow is simulated for a 60-year period from September 1, 1944, to August 31, 2004. Steady-state conditions are simulated prior to September 1, 1944, and represent conditions prior to use of ground water for irrigation. Irrigation, municipal, and industrial wells were simulated using the Multi-Node Well package of the modular three-dimensional ground-water flow model code, MODFLOW-2000, which allows simulation of flow and solutes through wells that are simulated in multiple nodes or layers. Ground-water flow, age, and transport of selected tracers were simulated using the Ground-Water Transport process of MODFLOW-2000. Simulated ground-water age was compared to interpreted ground-water age in six monitoring wells in the unconfined aquifer. The tracer chlorofluorocarbon-11 was simulated directly using Ground-Water Transport for comparison with concentrations measured in six monitoring wells and one public supply well screened in the upper confined aquifer. Three alternative model simulations indicate that simulation results are highly sensitive to the distribution of multilayer well bores where leakage

  13. CMAQ simulation of atmospheric CO2 concentration in East Asia: Comparison with GOSAT observations and ground measurements

    Science.gov (United States)

    Li, Rong; Zhang, Meigen; Chen, Liangfu; Kou, Xingxia; Skorokhod, Andrei

    2017-07-01

    Satellite observations are widely used in global CO2 assimilations, but their quality for use in regional assimilation systems has not yet been thoroughly determined. Validation of satellite observations and model simulations of CO2 is crucial for carbon flux inversions. In this study, we focus on evaluating the uncertainties of model simulations and satellite observations. The atmospheric CO2 distribution in East Asia during 2012 was simulated using a regional chemical transport model (RAMS-CMAQ) and compared with both CO2 column density (XCO2) from the Gases Observing SATellite (GOSAT) and CO2 concentrations from the World Data Centre for Greenhouse Gases (WDCGG). The results indicate that simulated XCO2 is generally lower than GOSAT XCO2 by 1.19 ppm on average, and their monthly differences vary from 0.05 to 2.84 ppm, with the corresponding correlation coefficients ranging between 0.1 and 0.67. CMAQ simulations are good to capture the CO2 variation as ground-based observations, and their correlation coefficients are from 0.62 to 0.93, but the average value of CMAQ simulation is 2.4 ppm higher than ground-based observation. Thus, we inferred that the GOSAT retrievals may overestimate XCO2, which is consistent with the validation of GOSAT XCO2 using Total Carbon Column Observing Network measurements. The near-surface CO2 concentration was obviously overestimated in GOSAT XCO2. Compared with the relatively small difference between CMAQ and GOSAT XCO2, the large difference in CO2 near surface or their vertical profiles indicates more improvements are needed to reduce the uncertainties in both satellite observations and model simulations.

  14. Slow Strain Rate Testing of Alloy 22 in Simulated Concentrated Ground Waters

    Energy Technology Data Exchange (ETDEWEB)

    King, K J; Wong, L L; Estill, J C; Rebak, R B

    2003-10-29

    The proposed engineering barriers for the high-level nuclear waste repository in Yucca Mountain include a double walled container and a detached drip shield. The candidate material for the external wall of the container is Alloy 22 (N06022). One of the anticipated degradation modes for the containers could be environmentally assisted cracking (EAC). The objective of the current research was to characterize the effect of applied potential and temperature on the susceptibility of Alloy 22 to EAC in simulated concentrated water (SCW) and other environments using the slow strain rate technique (SSRT). Results show that the temperature and applied potential have a strong influence on the susceptibility of Alloy 22 to suffer EAC in SCW solution. Limited results show that sodium fluoride solution is more detrimental than sodium chloride solution.

  15. Effective Installations Technique of Grounding Conductors for Metal Oxide Surge Arresters

    Energy Technology Data Exchange (ETDEWEB)

    Lee, B.H.; Kang, S.M. [Inha University, Inchon (Korea); Ryu, I.S. [Korea Electric Power Corporation, Seoul (Korea)

    2002-06-01

    This paper deals with the effects of grounding conductors for metal oxide surge arresters. When surge arresters are improperly installed, the results can cause costly damage of electrical equipments. In particular, the route of surge arrester connection is very important because bends and links of leads increase the impedances to lightning surges and tend to nullify the effectiveness of a grounding conductor. Therefore, there is a need to know how effective installation of lightning surge arresters is made in order to control voltage and to absorb energy at high lightning currents. The effectiveness of a grounding conductor and 18 [kV] metal oxide distribution line arresters was experimentally investigated under the lightning and oscillatory impulse voltages. Thus, the results are as follows; (1) The induced voltage of a grounding conductor is drastically not affected by length of a connecting line, but it is very sensitive to types of grounding conductor. (2) The coaxial cable having a low characteristic impedance is suitable as a grounding conductor. (3) It is also clear from these results that bonding the metal raceway enclosing the grounding conductor to the grounding electrode is very effective because of skin effect. (4) The induced voltages of grounding conductors for the oscillatory impulse voltages are approximately twice as large as those for the lightning impulse voltages. (author). 9 refs., 12 figs., 2 tabs.

  16. Thermal structure of the upper atmosphere of Venus simulated by a ground-to-thermosphere GCM

    Science.gov (United States)

    Gilli, G.; Lebonnois, S.; González-Galindo, F.; López-Valverde, M. A.; Stolzenbach, A.; Lefèvre, F.; Chaufray, J. Y.; Lott, F.

    2017-01-01

    We present here the thermal structure of the upper atmosphere of Venus predicted by a full self-consistent Venus General Circulation Model (VGCM) developed at Laboratoire de Météorologie Dynamique (LMD) and extended up to the thermosphere of the planet. Physical and photochemical processes relevant at those altitudes, plus a non-orographic GW parameterisation, have been added. All those improvements make the LMD-VGCM the only existing ground-to-thermosphere 3D model for Venus: a unique tool to investigate the atmosphere of Venus and to support the exploration of the planet by remote sounding. The aim of this paper is to present the model reference results, to describe the role of radiative, photochemical and dynamical effects in the observed thermal structure in the upper mesosphere/lower thermosphere of the planet. The predicted thermal structure shows a succession of warm and cold layers, as recently observed. A cooling trend with increasing latitudes is found during daytime at all altitudes, while at nighttime the trend is inverse above about 110 km, with an atmosphere up to 15 K warmer towards the pole. The latitudinal variation is even smaller at the terminator, in agreement with observations. Below about 110 km, a nighttime warm layer whose intensity decreases with increasing latitudes is predicted by our GCM. A comparison of model results with a selection of recent measurements shows an overall good agreement in terms of trends and order of magnitude. Significant data-model discrepancies may be also discerned. Among them, thermospheric temperatures are about 40-50 K colder and up to 30 K warmer than measured at terminator and at nighttime, respectively. The altitude layer of the predicted mesospheric local maximum (between 100 and 120 km) is also higher than observed. Possible interpretations are discussed and several sensitivity tests performed to understand the data-model discrepancies and to propose future model improvements.

  17. Three-dimensional simulations of ground motions in the Seattle region for earthquakes in the Seattle fault zone

    Science.gov (United States)

    Frankel, A.; Stephenson, W.

    2000-01-01

    We used the 3D finite-difference method to model observed seismograms of two earthquakes (ML 4.9 and 3.5) in the Seattle region and to simulate ground motions for hypothetical M 6.5 and M 5.0 earthquakes on the Seattle fault, for periods greater than 2 sec. A 3D velocity model of the Seattle Basin was constructed from studies that analyzed seismic-reflection surveys, borehole logs, and gravity and aeromagnetic data. The observations and the simulations highlight the importance of the Seattle Basin on long-period ground motions. For earthquakes occurring just south of the basin, the edge of the basin and the variation of the thickness of the Quaternary deposits in the basin produce much larger surface waves than expected from flat-layered models. The data consist of seismograms recorded by instruments deployed in Seattle by the USGS and the University of Washington (UW). The 3D simulation reproduces the peak amplitude and duration of most of the seismograms of the June 1997 Bremerton event (ML 4.9) recorded in Seattle. We found the focal mechanism for this event that best fits the observed seismograms in Seattle by combining Green's functions determined from the 3D simulations for the six fundamental moment couples. The February 1997 event (ML 3.5) to the south of the Seattle Basin exhibits a large surface-wave arrival at UW whose amplitude is matched by the synthetics in our 3D velocity model, for a source depth of 9 km. The M 6.5 simulations incorporated a fractal slip distribution on the fault plane. These simulations produced the largest ground motions in an area that includes downtown Seattle. This is mainly caused by rupture directed up dip toward downtown, radiation pattern of the source, and the turning of S waves by the velocity gradient in the Seattle basin. Another area of high ground motion is located about 13 km north of the fault and is caused by an increase in the amplitude of higher-mode Rayleigh waves caused by the thinning of the Quaternary

  18. An Efficient approach for Shielding Effect of the Grounding Electrodes under Impulse-Current Voltage based on Matlab

    Directory of Open Access Journals (Sweden)

    Ms. Kalyani Pole

    2012-06-01

    Full Text Available The lightning current waveform has a majorinfluence on the dynamic performance of groundelectrodes. While high lightning current intensityimproves the dynamic grounding performance dueto ionization of the soil, very fast fronted pulsesmight worsen the performance in case of inductivebehaviour. The previous analysis has often beenbased on quasistatic approximation that is notapplicable to very fast fronted pulses. PreviousResearch focused on analyzing the impulse currentdispersal regularity of different branches wheninjecting at one point. Comparing with the leakagecurrent distribution of a single ground electrode, itis found that the leakage currents along thebranches increase with the distance to the currentfeed point, and the more conductors near theinjection point, the more uneven the leakagecurrent distribution is. In this paper by simulationresult we indicate that shielding effect should betaken into account when analyzing the impulsecharacteristics of grounding electrodes. Based onthe simulation results, new empirical formulasapplicable for slow and very fast fronted lightningcurrent pulses are proposed. The effects of theionization of the soil are disregarded; therefore, thenew formulas are applicable for a conservativeestimate of the upper bound of the impulseimpedance of ground electrodes. In this paper wealso analyze and compare by the MATLAB. We alsoprovide dynamic behavior of ground electrodes.

  19. Effects of Manufacturing Process in Crash Simulations

    Directory of Open Access Journals (Sweden)

    Šašek J.

    2010-07-01

    Full Text Available This article describes an impact of a manufacturing, which can significantly change real parts behavior. The influence of technology process is neglected in regular simulations. However, advanced finite elements solvers make possible to involve themanufacturing process in final simulations. It brings distortions and initial distribution of stress and strain into simulations. The possibilities are demonstrated on a crash simulation of a simple box-beam, where stamping and welding processes and spring-back are considered. All mentioned operations are performed in Virtual Performance Solution. The effects of manufacturing process are discussed with a respect to common simulation practice at the end of the paper.

  20. Analysis of landslide mitigation effects using Ground Penetrating Radar

    Science.gov (United States)

    Ristic, Aleksandar; Govedarica, Miro; Vrtunski, Milan; Petrovacki, Dusan

    2013-04-01

    Area of Ground Penetrating Radar (GPR) technology applications becomes wider nowadays. It includes utility mapping as important part of civil engineering applications, geological structure and soil analyses, applications in agriculture, etc. Characteristics of the technology make it suitable for structure analysis of shallow landslides, whose number and impact on environment is dominant in the region. Especially when shallow landslide endangers some man-made structures such as buildings, roads or bridges, analysis of GPR data can yield very useful results. The results of GPR data analysis of the shallow landslide are represented here. It is situated on the mountain Fruska Gora in Serbia. Despite its dimensions (50x20m) this landslide was interesting for analysis for two reasons: - The landslide occurred at the part of the single road between the cement factory and the marl mine. The cement factory "Lafarge" in Beocin (Fruska Gora) is the largest cement manufacturer in the country. One of major priorities of the factory management is to keep the function of this road. The road is heavily exploited and over the years it led to landslide movements and damaging of the road itself. - The landslide dates back to earlier period and the mitigation measures were performed twice. Laying the foundation of the retaining wall was not performed during the first mitigation measures. The second mitigation measures were performed in 2010 and included detailed geotechnical analysis of the location with the appropriate foundation laying. Since the GPR technology can produce high resolution images of subsurface it provides clear insight into the current state of surveyed location. That kind of analysis is necessary to maintain permanent functionality of the road and to check the status of mitigation measures. Furthermore, the location characteristics do not allow easy access so the possibilities of other analysis technologies application are limited. In order to assess the effects of

  1. Detection of the Zeeman effect in atmospheric O2 using a ground-based microwave radiometer

    Science.gov (United States)

    Navas-Guzmán, Francisco; Kämpfer, Niklaus; Murk, Axel; Larsson, Richard; Buehler, Stefan A.; Eriksson, Patrick

    2015-04-01

    In this work we study the Zeeman effect on stratospheric O2 using ground-based microwave radiometer measurements. The Zeeman effect is a phenomenon which occurs when an external magnetic field interacts with a molecule or an atom of total electron spin different from zero. Such an interaction will split an original energy level into several sub-levels [1]. In the atmosphere, oxygen is an abundant molecule which in its ground electronic state has a permanent magnetic dipole moment coming from two parallel electron spins. The interaction of the magnetic dipole moment with the Earth magnetic field leads to a Zeeman splitting of the O2 rotational transitions which polarizes the emission spectra. A special campaign was carried out in order to measure this effect in the oxygen emission line centered at 53.07 GHz in Bern (Switzerland). The measurements were possible using a Fast Fourier Transform (FFT) spectrometer with 1 GHz of band width to measure the whole oxygen emission line centered at 53.07 GHz and a narrow spectrometer (4 MHz) to measure the center of the line with a very high resolution (1 kHz). Both a fixed and a rotating mirror were incorporated to the TEMPERA (TEMPERature RAdiometer) radiometer in order to be able to measure under different observational angles. This new configuration allowed us to change the angle between the observational path and the Earth magnetic field direction. The measured spectra showed a clear polarized signature when the observational angles were changed evidencing the Zeeman effect in the oxygen molecule. In addition, simulations carried out with the Atmospheric Radiative Transfer Simulator (ARTS) [2] allowed us to verify the microwave measurements showing a very good agreement between model and measurements. The incorporation of this effect to the forward model will allow to extend the temperature retrievals beyond 50 km. This improvement in the forward model will be very useful for the assimilation of brightness temperatures in

  2. Simulation of near-fault bedrock strong ground-motion field by explicit finite element method

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiao-zhi; HU Jin-jun; XIE Li-li; WANG Hai-yun

    2006-01-01

    Based on presumed active fault and corresponding model, this paper predicted the near-fault ground motion filed of a scenario earthquake (Mw=6 3/4 ) in an active fault by the explicit finite element method in combination with the source time function with improved transmitting artificial boundary and with high-frequency vibration contained.The results indicate that the improved artificial boundary is stable in numerical computation and the predicted strong ground motion has a consistent characteristic with the observed motion.

  3. Simulation of vestibular flight illusions on the ground%前庭性飞行错觉地面模拟

    Institute of Scientific and Technical Information of China (English)

    黄炜; 于立身; 季思菊; 李交杰; 张刚林; 黄佳怡; 马志超

    2012-01-01

    Objective To promote the pilot's experience on vestibular flight illusions under simulated flying environment and to investigate the illusion induced rate and the result of vestibular illusion simulation on the ground.Methods Forty-six pilots experienced vestibular flight illusions by the simulator that was according to the mechanism of generating vestibular flight illusions.The orientation feeling,feedback of personal state,response of autonomic nervous system and the evaluation of training effect were recorded.Results The total vestibular illusion induced rate was 91.7%.The induced rate of absence of rotation illusion,opposite-rotation illusion,Coriolis illusion,somatogravic illusion,G-excess illusion and nystagmus effect was respectively 100.0%,100.0%,91.7%,78.6%,94.4% and 100.0%.All pilots reported experienced vestibular flight illusions.In the analysis of assessing induced acute motion sickness only 4 person-times showed transient reflex at MⅡ level,and no reflex more severe than M Ⅲ or MS level was observed.Pilots assessed such experience was helpful in knowing illusions and preventing spatial disorientation accidents.Conclusion The flight illusion simulator can effectively keep pilots experiencing flight vestibular illusions upon high induced rate,proper stimulation and notable effects.%目的 让飞行员在地面上体验模拟飞行条件下的前庭性飞行错觉,观察错觉的诱发率和地面模拟前庭性飞行错觉的效果. 方法 根据前庭性飞行错觉的发生机制,利用飞行错觉模拟器模拟飞行错觉.46名歼(强)击机飞行员进行错觉体验,记录其空间感觉主诉、对自身状态的反馈、自主神经反应及对训练效果的评价. 结果 前庭性错觉总诱发率为91.7%;不旋转错觉诱发率100.0%,反旋转错觉100.0%,Coriolis错觉91.7%,躯体重力错觉78.6%,超重错觉94.4%,眼震效应100.0%.本组飞行员错觉体验率为100.0%.在飞行错觉体验过程

  4. Survival of B. Horneckiae Spores Under Ground-simulated Space Conditions

    Science.gov (United States)

    Schanche, Bradley

    2012-01-01

    To prevent forward contamination and maintain the scientific integrity of future life detection missions, it is important to characterize and attempt to eliminate terrestrial microorganisms associated with exploratory spacecraft and landing vehicles. Among the organisms isolated from spacecraft-associated habitats, spore-forming microbes are highly resistant to various physical and chemical conditions, which include ionizing and UV radiation, desiccation and oxidative stress, and the harsh environment of outer space or planetary surfaces. Recently a radiation resistant, spore forming bacterial isolate, Bacillus horneckiae, was isolated from a clean room of the Kennedy Space Center where the Phoenix spacecraft was assembled. The exceptionally high tolerance of extreme conditions demonstrated by sporeforming bacteria highlighted the need to assess the viability of these microbes in situ (in real) space. The proposed BOSS (Biofilm Organisms Surfing Space) project aims to understand the mechanisms by which biofilm forming organisms, such as B. horneckiae, will potentially be able to withstand harsh space conditions. As previously stated, the spore producing ability of these species gives them increased survivability to harsh conditions. Some of the spores will have the protective exosporium layer artificially removed before the test to determine if the existence of this layer significantly changes the survivability during the mission. In preparation for that experiment, we analyzed spores which were exposed during a ground simulation, the EXPOSE R2 Biofilm Organisms Surfing Space (BOSS). Previous to exposure, spores were deposited onto spacecraft grade aluminum coupons in a spore suspension calculated to contain between 10(exp 7) and 10(exp 8) spores. This precursor series will be used to establish a baseline survivability function for comparison with the future flight tests during EXPOSE-R. For each coupon, a 10% polyvinyl alcohol (PVA) film was applied and peeled

  5. Coping with the Stigma of Mental Illness: Empirically-Grounded Hypotheses from Computer Simulations

    Science.gov (United States)

    Kroska, Amy; Har, Sarah K.

    2011-01-01

    This research demonstrates how affect control theory and its computer program, "Interact", can be used to develop empirically-grounded hypotheses regarding the connection between cultural labels and behaviors. Our demonstration focuses on propositions in the modified labeling theory of mental illness. According to the MLT, negative societal…

  6. Simulation of Near-Fault High-Frequency Ground Motions from the Representation Theorem

    Science.gov (United States)

    Beresnev, Igor A.

    2017-07-01

    "What is the maximum possible ground motion near an earthquake fault?" is an outstanding question of practical significance in earthquake seismology. In establishing a possible theoretical cap on extreme ground motions, the representation integral of elasticity, providing an exact, within limits of applicability, solution for fault radiation at any frequency, is an under-utilized tool. The application of a numerical procedure leading to synthetic ground displacement, velocity, and acceleration time histories to modeling of the record at the Lucerne Valley hard-rock station, uniquely located at 1.1 km from the rupture of the M w 7.2 Landers, California event, using a seismologically constrained temporal form of slip on the fault, reveals that the shape of the displacement waveform can be modeled closely, given the simplicity of the theoretical model. High precision in the double integration, as well as carefully designed smoothing and filtering, are necessary to suppress the numerical noise in the high-frequency (velocity and acceleration) synthetic motions. The precision of the integration of at least eight decimal digits ensures the numerical error in the displacement waveforms generally much lower than 0.005% and reduces the error in the peak velocities and accelerations to the levels acceptable to make the representation theorem a reliable tool in the practical evaluation of the magnitude of maximum possible ground motions in a wide-frequency range of engineering interest.

  7. Computer Simulation and Optimization of the Process of Thawing of Grounds Using Microwave Energy

    Science.gov (United States)

    Nekrasov, S. A.; Volkov, V. S.

    2017-01-01

    In this article, consideration is given to a mathematical model and a numerical method to calculate and optimize the process of high-speed thawing of grounds using microwave energy. Relevant examples of calculations and an analysis of results are presented.

  8. Coping with the Stigma of Mental Illness: Empirically-Grounded Hypotheses from Computer Simulations

    Science.gov (United States)

    Kroska, Amy; Har, Sarah K.

    2011-01-01

    This research demonstrates how affect control theory and its computer program, "Interact", can be used to develop empirically-grounded hypotheses regarding the connection between cultural labels and behaviors. Our demonstration focuses on propositions in the modified labeling theory of mental illness. According to the MLT, negative societal…

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1992-01-01

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

  10. Geohydrological characterization, water-chemistry, and ground-water flow simulation model of the Sonoma Valley area, Sonoma County, California

    Science.gov (United States)

    Farrar, Christopher D.; Metzger, Loren F.; Nishikawa, Tracy; Koczot, Kathryn M.; Reichard, Eric G.; Langenheim, V.E.

    2006-01-01

    changes by region. In recent years, pumping depressions have developed southeast of Sonoma and southwest of El Verano. Water-chemistry data for samples collected from 75 wells during 2002-04 indicate that the ground-water quality in the study area generally is acceptable for potable use. The water from some wells, however, contains one or more constituents in excess of the recommended standards for drinking water. The chemical composition of water from creeks, springs, and wells sampled for major ions plot within three groups on a trilinear diagram: mixed-bicarbonate, sodium-mixed anion, and sodium-bicarbonate. An area of saline ground water in the southern part of the Sonoma Valley appears to have shifted since the late 1940s and early 1950s, expanding in one area, but receding in another. Sparse temperature data from wells southwest of the known occurrence of thermal water suggest that thermal water may be present beneath a larger part of the valley than previously thought. Thermal water contains higher concentrations of dissolved minerals than nonthermal waters because mineral solubilities generally increase with temperature. Geohydrologic Characterization, Water-Chemistry, and Ground-Water Flow Simulation Model of the Sonoma Valley Area, Sonoma County, California Oxygen-18 (d18 O) and deuterium (dD) values for water from most wells plot along the global meteoric water line, indicating that recharge primarily is derived from the direct infiltration of precipitation or the infiltration of seepage from creeks. Samples from shallow- and intermediate-depth wells located near Sonoma Creek and (or) in the vicinity of Shellville plot to the right of the global meteoric water line, indicating that these waters are partly evaporated. The d18 O and dD composition of water from sampled wells indicates that water from wells deeper than 200 feet is isotopically lighter (more negative) than water from wells less than 200 feet deep, possibly indicating that older ground wate

  11. Confident but not theoretically grounded – experienced simulation educators’ perceptions of their own professional development

    Science.gov (United States)

    Allvin, Renée; Berndtzon, Magnus; Carlzon, Liisa; Edelbring, Samuel; Hult, Håkan; Hultin, Magnus; Karlgren, Klas; Masiello, Italo; Södersved Källestedt, Marie-Louise; Tamás, Éva

    2017-01-01

    Background Medical simulation enables the design of learning activities for competency areas (eg, communication and leadership) identified as crucial for future health care professionals. Simulation educators and medical teachers follow different career paths, and their education backgrounds and teaching contexts may be very different in a simulation setting. Although they have a key role in facilitating learning, information on the continuing professional development (pedagogical development) of simulation educators is not available in the literature. Objectives To explore changes in experienced simulation educators’ perceptions of their own teaching skills, practices, and understanding of teaching over time. Methods A qualitative exploratory study. Fourteen experienced simulation educators participated in individual open-ended interviews focusing on their development as simulation educators. Data were analyzed using an inductive thematic analysis. Results Marked educator development was discerned over time, expressed mainly in an altered way of thinking and acting. Five themes were identified: shifting focus, from following to utilizing a structure, setting goals, application of technology, and alignment with profession. Being confident in the role as an instructor seemed to constitute a foundation for the instructor’s pedagogical development. Conclusion Experienced simulation educators’ pedagogical development was based on self-confidence in the educator role, and not on a deeper theoretical understanding of teaching and learning. This is the first clue to gain increased understanding regarding educational level and possible education needs among simulation educators, and it might generate several lines of research for further studies. PMID:28176931

  12. Confident but not theoretically grounded - experienced simulation educators' perceptions of their own professional development.

    Science.gov (United States)

    Allvin, Renée; Berndtzon, Magnus; Carlzon, Liisa; Edelbring, Samuel; Hult, Håkan; Hultin, Magnus; Karlgren, Klas; Masiello, Italo; Södersved Källestedt, Marie-Louise; Tamás, Éva

    2017-01-01

    Medical simulation enables the design of learning activities for competency areas (eg, communication and leadership) identified as crucial for future health care professionals. Simulation educators and medical teachers follow different career paths, and their education backgrounds and teaching contexts may be very different in a simulation setting. Although they have a key role in facilitating learning, information on the continuing professional development (pedagogical development) of simulation educators is not available in the literature. To explore changes in experienced simulation educators' perceptions of their own teaching skills, practices, and understanding of teaching over time. A qualitative exploratory study. Fourteen experienced simulation educators participated in individual open-ended interviews focusing on their development as simulation educators. Data were analyzed using an inductive thematic analysis. Marked educator development was discerned over time, expressed mainly in an altered way of thinking and acting. Five themes were identified: shifting focus, from following to utilizing a structure, setting goals, application of technology, and alignment with profession. Being confident in the role as an instructor seemed to constitute a foundation for the instructor's pedagogical development. Experienced simulation educators' pedagogical development was based on self-confidence in the educator role, and not on a deeper theoretical understanding of teaching and learning. This is the first clue to gain increased understanding regarding educational level and possible education needs among simulation educators, and it might generate several lines of research for further studies.

  13. The effect of ground electrode on the sensitivity, symmetricity and technical feasibility of scalp EEG recordings.

    Science.gov (United States)

    Paukkunen, Antti Kimmo Olavi; Sepponen, Raimo

    2008-09-01

    Although the choice of the measurement reference strongly affects the measurement sensitivity, validity and comparability, selection is often based on tradition, convenience and comparability to earlier results [Dien in Behav Res Methods Ins C 30(1):34-43, 1998; Femi and Sundor in Int J Psychosom 36(1-4):23-33; 1989]. Artificial means can be applied to compensate for the referential issues, but they cannot restore any lost data. The validity of the recorded data is ultimately defined by the hardware setup. In this simulation study, common average ground reference (AR) is characterized and compared to two alternative common ground reference schemes in respect to their influence on the sensitivity distribution and technical feasibility of scalp EEG recording. It was found that, despite the polar average reference effect [Junghöfer et al. in Clin Neurophysiol 110(6):1149-1155; 1999], AR merits a significantly higher symmetricity and should be promoted generally not only in high-electrode-density studies, but also in low-channel-count studies if the stringent design requirements can be met. In low-electrode-density studies, balancing the setup may prove challenging, but successful implementation can provide nearly undistorted data. Isolation of the system is a critical parameter, but technological advances enable the requirements to be fulfilled. A physical ground should be applied if high isolation is not applicable or if it is defined by the application. The results will apply for the applied homogenous concentric 3-sphere model, but should be further studied in a realistic context if more detailed and case-sensitive information is required; the underlying phenomena are generally applicable.

  14. Simulated water budgets and ground-water/surface-water interactions in Bushkill and parts of Monocacy Creek watersheds, Northampton County, Pennsylvania--a preliminary study with identification of data needs

    Science.gov (United States)

    Risser, Dennis W.

    2006-01-01

    per second. Raising the deepest sump to an altitude of 200 feet caused the simulated discharge to the quarry to decrease about 14 cubic feet per second.Decreasing the hydraulic conductivity of the streambed of Bushkill Creek in the reach of large losses of flow caused simulated ground-water levels to decline and ground-water discharge to a quarry to decrease from 74 to 45 cubic feet per second. Decreasing the hydraulic conductivity of a hypothesized highly transmissive zone with a plug of relatively impermeable material caused ground-water levels to increase east of the plug and decline west of the plug, and decreased the discharge to a quarry from 74 to 53 cubic feet per second. Preliminary results of the study have significant limitations, which need to be recognized by the user. The results demonstrated the usefulness of ground-water modeling with available data sets, but as more data become available through field studies, a more complete evaluation could be conducted of the preliminary assumptions in the conceptual model, model sensitivity, and effects of boundary conditions. Additional streamflow and ground-water-level measurements would be needed to better quantify recharge and aquifer properties, particularly the anisotropy of carbonate rocks. Measurements of streamflow losses at average, steady-state hydrologic conditions could provide a more accurate estimate of ground-water recharge from this source, which directly affects water budgets and contributing areas simulated by the model.

  15. Temporal dynamics of the gut microbiota in people sharing a confined environment, a 520-day ground-based space simulation, MARS500

    National Research Council Canada - National Science Library

    Silvia Turroni; Simone Rampelli; Elena Biagi; Clarissa Consolandi; Marco Severgnini; Clelia Peano; Sara Quercia; Matteo Soverini; Franck G Carbonero; Giovanna Bianconi; Petra Rettberg; Francesco Canganella; Patrizia Brigidi; Marco Candela

    2017-01-01

    .... Results The MARS500 project, the longest ground-based space simulation ever, provided us with a unique opportunity to trace the crew microbiota over 520 days of isolated confinement, such as that...

  16. GIPL1.3 simulated mean annual ground temperature (MAGT) in Celsius averaged for particular decade for the entire Alaskan permafrost domain. NAD83, Alaska Albers projection

    Data.gov (United States)

    Arctic Landscape Conservation Cooperative — This raster, created in 2010, is output from the Geophysical Institute Permafrost Lab (GIPL) model and represents simulated mean annual ground temperature (MAGT) in...

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

    Science.gov (United States)

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

    1995-01-01

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

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

    Science.gov (United States)

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

    2013-12-01

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

  19. Effective dose conversion coefficients for radionuclides exponentially distributed in the ground

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Kimiaki [Japan Atomic Energy Agency, Tokyo (Japan); Ishigure, Nobuhito [Nagoya University, Graduate School of Medicine, Nagoya City (Japan); Petoussi-Henss, Nina; Schlattl, Helmut [Helmholtz Zentrum Muenchen-German Research Center for Environmental Health, Department of Radiation Physics and Diagnostics, Neuherberg (Germany)

    2012-11-15

    In order to provide fundamental data required for dose evaluation due to environmental exposures, effective dose conversion coefficients, that is, the effective dose rate per unit activity per unit area, were calculated for a number of potentially important radionuclides, assuming an exponential distribution in ground, over a wide range of relaxation depths. The conversion coefficients were calculated for adults and a new-born baby on the basis of dosimetric methods that the authors and related researchers have previously developed, using Monte Carlo simulations and anthropomorphic computational phantoms. The differences in effective dose conversion coefficients due to body size between the adult and baby phantoms were found to lie within 50 %, for most cases; however, for some low energies, differences could amount to a factor of 3. The effective dose per unit source intensity per area was found to decrease by a factor of 2-5, for increasing relaxation depths from 0 to 5 g/cm{sup 2}, above a source energy of 50 keV. It is also shown that implementation of the calculated coefficients into the computation of the tissue weighting factors and the adult reference computational phantoms of ICRP Publication 103 does not significantly influence the effective dose conversion coefficients of the environment. Consequently, the coefficients shown in this paper could be applied for the evaluation of effective doses, as defined according to both recommendations of ICRP Publications 103 and 60. (orig.)

  20. Grounded cognition.

    Science.gov (United States)

    Barsalou, Lawrence W

    2008-01-01

    Grounded cognition rejects traditional views that cognition is computation on amodal symbols in a modular system, independent of the brain's modal systems for perception, action, and introspection. Instead, grounded cognition proposes that modal simulations, bodily states, and situated action underlie cognition. Accumulating behavioral and neural evidence supporting this view is reviewed from research on perception, memory, knowledge, language, thought, social cognition, and development. Theories of grounded cognition are also reviewed, as are origins of the area and common misperceptions of it. Theoretical, empirical, and methodological issues are raised whose future treatment is likely to affect the growth and impact of grounded cognition.

  1. Steel Moment-Resisting Frame Responses in Simulated Strong Ground Motions: or How I Learned to Stop Worrying and Love the Big One

    OpenAIRE

    Olsen, Anna

    2008-01-01

    This thesis studies the response of steel moment-resisting frame buildings in simulated strong ground motions. I collect 37 simulations of crustal earthquakes in California. These ground motions are applied to nonlinear finite element models of four types of steel moment frame buildings: six- or twenty-stories with either a stiffer, higherstrength design or a more flexible, lower-strength design. I also consider the presence of fracture-prone welds in each design. Since these b...

  2. Ground-water hydrology of Ogden Valley and surrounding area, eastern Weber County, UT, and simulation of ground-water flow in the Valley-fill aquifer system

    Science.gov (United States)

    Avery, Charles

    1994-01-01

    The ground-water resources in Ogden Valley, eastern Weber County, Utah, were the subject of a study to provide a better understanding of the hydrologic system in the valley and to estimate the hydrologic effects of future ground-water development. The study area included the drainage basin of the Ogden River upstream from Pineview Reservoir dam and the drainage basin of Wheeler Creek. Ogden Valley and the surrounding area are underlain by rocks that range in age from Precambrian to Quaternary.The consolidated rocks that transmit and yield the most water in the area surrounding Ogden Valley are the Paleozoic carbonate rocks and the Wasatch Formation of Tertiary age. Much of the recharge to the consolidated rocks is from snowmelt that infiltrates the Wasatch Formation, which underlies a large part of the study area. Discharge from the consolidated rocks is by streams, evapotranspiration, springs, subsurface outflow, and pumping from wells. Water in the consolidated rocks is a calcium bicarbonate type and has a dissolved-solids concentration of less than 250 milligrams per liter.

  3. Documentation of finite-difference model for simulation of three-dimensional ground-water flow

    Science.gov (United States)

    Trescott, Peter C.; Larson, S.P.

    1976-01-01

    User experience has indicated that the documentation of the model of three-dimensional ground-water flow (Trescott and Larson, 1975) should be expanded. This supplement is intended to fulfill that need. The original report emphasized the theory of the strongly implicit procedure, instructions for using the groundwater-flow model, and practical considerations for application. (See also W76-02962 and W76-13085) (Woodard-USGS)

  4. Simulative investigation on head injuries of electric self-balancing scooter riders subject to ground impact.

    Science.gov (United States)

    Xu, Jun; Shang, Shi; Qi, Hongsheng; Yu, Guizhen; Wang, Yunpeng; Chen, Peng

    2016-04-01

    The safety performance of an electric self-balancing scooter (ESS) has recently become a main concern in preventing its further wide application as a major candidate for green transportation. Scooter riders may suffer severe brain injuries in possible vehicle crash accidents not only from contact with a windshield or bonnet but also from secondary contact with the ground. In this paper, virtual vehicle-ESS crash scenarios combined with finite element (FE) car models and multi-body scooter/human models are set up. Post-impact kinematic gestures of scooter riders under various contact conditions, such as different vehicle impact speeds, ESS moving speeds, impact angles or positions, and different human sizes, are classified and analyzed. Furthermore, head-ground impact processes are reconstructed using validated FE head models, and important parameters of contusion and laceration (e.g., coup or contrecoup pressures and Von Mises stress and the maximum shear stress) are extracted and analyzed to assess the severity of regional contusion from head-ground contact. Results show that the brain injury risk increases with vehicle speeds and ESS moving speeds and may provide fundamental knowledge to popularize the use of a helmet and the vehicle-fitted safety systems, and lay a strong foundation for the reconstruction of ESS-involved accidents. There is scope to improve safety for the use of ESS in public roads according to the analysis and conclusions.

  5. The Effects of Marine Simulators on Training

    Directory of Open Access Journals (Sweden)

    Rashed Al Shahin

    2017-03-01

    Full Text Available Simulators have increased its usefulness in marine training over the years. Literature cites its many advantages which should ultimately lead to the increase in sea safety. However, more remarked than the discomfort felt by the trainee due to the lack of human interaction, simulation-training was noted to be costly and does not provide a clear indication of its value in organizations as no information supports this. A comparison of other technology which could be used for training is shown to provide an insight to the probable technology-based alternatives for simulators. In the search for the effects of marine-simulators on training, a few literature indicated its effects. Studies indeed specify favorable effects of simulators to training. However, no definite or quantifiable explanations were shown to relate training to its ultimate purpose of improving sea safety. Studies reviewed explored the effects of training to teamwork and the effects of training on the cognitive abilities of trainees. The Lewin study on the effects of CRM training indicated positive outcomes but was unclear about the link of training effectiveness with safety. The perception study revealed significant results in the perceived change of attitude, knowledge, and skills. The other study was on determining the physiological response related to cognitive activities which revealed that a rise in frequency values was observed during problemsolving in navigational situations. Simulator systems in training institutions were examined to provide a glimpse of how training may be made more effective.

  6. Experimental Investigation Into the Aerodynamic Ground Effect of a Tailless Chevron and Lambda-shaped UCAVs

    Science.gov (United States)

    2006-03-01

    Significant advances during the last quarter-century in computing capabilities, electronics miniaturization, communications , guidance, navigation, and...Grumman X-47. The X-45 will combine advance air vehicle hardware, including integrated sensors, communication , navigation equipment and low...USNR for UCAV Ground Effects Test**** %****** Re-adapted by Won In, Capt, USAF for UCAV Ground Efects Test ****** %******************* Calculation

  7. Unsteady Computations of a Jet in a Crossflow with Ground Effect

    Science.gov (United States)

    Pandya, Shishir; Murman, Scott; Venkateswaran, Sankaran; Kwak, Dochan (Technical Monitor)

    2002-01-01

    A numerical study of a jet in crossflow with ground effect is conducted using OVERFLOW with dual time-stepping and low Mach number preconditioning. The results of the numerical study are compared to an experiment to show that the numerical methods are capable of capturing the dominant features of the flow field as well as the unsteadiness associated with the ground vortex.

  8. Simulation of ground-water flow and evaluation of water-management alternatives in the upper Charles River basin, eastern Massachusetts

    Science.gov (United States)

    DeSimone, Leslie A.; Walter, Donald A.; Eggleston, John R.; Nimiroski, Mark T.

    2002-01-01

    Ground water is the primary source of drinking water for towns in the upper Charles River Basin, an area of 105 square miles in eastern Massachusetts that is undergoing rapid growth. The stratified-glacial aquifers in the basin are high yield, but also are thin, discontinuous, and in close hydraulic connection with streams, ponds, and wetlands. Water withdrawals averaged 10.1 million gallons per day in 1989?98 and are likely to increase in response to rapid growth. These withdrawals deplete streamflow and lower pond levels. A study was conducted to develop tools for evaluating water-management alternatives at the regional scale in the basin. Geologic and hydrologic data were compiled and collected to characterize the ground- and surface-water systems. Numerical flow modeling techniques were applied to evaluate the effects of increased withdrawals and altered recharge on ground-water levels, pond levels, and stream base flow. Simulation-optimization methods also were applied to test their efficacy for management of multiple water-supply and water-resource needs. Steady-state and transient ground-water-flow models were developed using the numerical modeling code MODFLOW-2000. The models were calibrated to 1989?98 average annual conditions of water withdrawals, water levels, and stream base flow. Model recharge rates were varied spatially, by land use, surficial geology, and septic-tank return flow. Recharge was changed during model calibration by means of parameter-estimation techniques to better match the estimated average annual base flow; area-weighted rates averaged 22.5 inches per year for the basin. Water withdrawals accounted for about 7 percent of total simulated flows through the stream-aquifer system and were about equal in magnitude to model-calculated rates of ground-water evapotranspiration from wetlands and ponds in aquifer areas. Water withdrawals as percentages of total flow varied spatially and temporally within an average year; maximum values were

  9. Sensitivity of ground motion parameters to local site effects for areas characterised by a thick buried low-velocity layer.

    Science.gov (United States)

    Farrugia, Daniela; Galea, Pauline; D'Amico, Sebastiano; Paolucci, Enrico

    2016-04-01

    these analyses. The amplification functions were extracted using the programme SITE_AMP (Boore, 2003), which computes amplifications based on the square root of the effective seismic impedance. Sensitivity indices were obtained by changing two parameters (thickness and shear-wave velocity) of the different layers while keeping the others constant. Additional analyses were carried out by producing various profiles within specified boundaries which are able to fit the experimental data. The analyses also show the important role that the shear-wave velocity profiles play in ground motion simulations. The results obtained highlight the importance of the correct knowledge of both the properties of the Upper Coralline Limestone and the Blue Clay, especially the Blue Clay thickness.

  10. Achieving sustainable ground-water management by using GIS-integrated simulation tools: the EU H2020 FREEWAT platform

    Science.gov (United States)

    Rossetto, Rudy; De Filippis, Giovanna; Borsi, Iacopo; Foglia, Laura; Toegl, Anja; Cannata, Massimiliano; Neumann, Jakob; Vazquez-Sune, Enric; Criollo, Rotman

    2017-04-01

    In order to achieve sustainable and participated ground-water management, innovative software built on the integration of numerical models within GIS software is a perfect candidate to provide a full characterization of quantitative and qualitative aspects of ground- and surface-water resources maintaining the time and spatial dimension. The EU H2020 FREEWAT project (FREE and open source software tools for WATer resource management; Rossetto et al., 2015) aims at simplifying the application of EU water-related Directives through an open-source and public-domain, GIS-integrated simulation platform for planning and management of ground- and surface-water resources. The FREEWAT platform allows to simulate the whole hydrological cycle, coupling the power of GIS geo-processing and post-processing tools in spatial data analysis with that of process-based simulation models. This results in a modeling environment where large spatial datasets can be stored, managed and visualized and where several simulation codes (mainly belonging to the USGS MODFLOW family) are integrated to simulate multiple hydrological, hydrochemical or economic processes. So far, the FREEWAT platform is a large plugin for the QGIS GIS desktop software and it integrates the following capabilities: • the AkvaGIS module allows to produce plots and statistics for the analysis and interpretation of hydrochemical and hydrogeological data; • the Observation Analysis Tool, to facilitate the import, analysis and visualization of time-series data and the use of these data to support model construction and calibration; • groundwater flow simulation in the saturated and unsaturated zones may be simulated using MODFLOW-2005 (Harbaugh, 2005); • multi-species advective-dispersive transport in the saturated zone can be simulated using MT3DMS (Zheng & Wang, 1999); the possibility to simulate viscosity- and density-dependent flows is further accomplished through SEAWAT (Langevin et al., 2007); • sustainable

  11. Preliminary Results on Simulations of Ground Level Enhancements (GLEs) detected by The High Altitude Water Cherenkov Observatory (HAWC)

    Science.gov (United States)

    Enriquez Rivera, O.; Lara, A.

    2014-12-01

    The High Altitude Water Cherenkov Observatory (HAWC) is currently under construction at the Sierra Negra Volcano, Puebla in Mexico. Located 4100 m above sea level, this large array is mainly designed to observe high energy gamma rays (TeV). However, by recording scaler data that correspond to the rates of individual photomultiplier tubes, the detection and study of solar energetic particles (known as Ground Level Enhancements) as well as the decrease of the cosmic ray flux due to solar transients (known as Forbush decreases) will also be possible. In order to determine the response of the array to solar transients, we have performed simulations of the scaler output using different sub-array configurations. We present here our preliminary results of such simulations and their comparison with observed Forbush decreases.

  12. T-4G Simulator and T-4 Ground Training Devices in USAF Undergraduate Pilot Training.

    Science.gov (United States)

    Woodruff, Robert R.; Smith, James F.

    The objective of the project was to investigate the utility of using an A/F37A-T4G T-37 flight simulator within the context of Air Force undergraduate pilot training. Twenty-one subjects, selected from three undergraduate pilot training classes, were given contact flight training in a TP4G/EPT simulator before going to T-37 aircraft for further…

  13. 3D simulation of near-fault strong ground motion:comparison between surface rupture fault and buried fault

    Institute of Scientific and Technical Information of China (English)

    Liu Qifang; Yuan Yifan; Jin Xing

    2007-01-01

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

  14. Modeling of Regional Climate Change Effects on Ground-Level Ozone and Childhood Asthma

    Science.gov (United States)

    Sheffield, Perry E.; Knowlton, Kim; Carr, Jessie L.; Kinney, Patrick L.

    2011-01-01

    Background The adverse respiratory effects of ground-level ozone are well-established. Ozone is the air pollutant most consistently projected to increase under future climate change. Purpose To project future pediatric asthma emergency department visits associated with ground-level ozone changes, comparing 1990s to 2020s. Methods This study assessed future numbers of asthma emergency department visits for children aged 0–17 years using (1) baseline New York City metropolitan area emergency department rates, (2) a dose–response relationship between ozone levels and pediatric asthma emergency department visits, and (3) projected daily 8-hour maximum ozone concentrations for the 2020s as simulated by a global-to-regional climate change and atmospheric chemistry model. Sensitivity analyses included population projections and ozone precursor changes. This analysis occurred in 2010. Results In this model, climate change could cause an increase in regional summer ozone-related asthma emergency department visits for children aged 0–17 years of 7.3% across the New York City metropolitan region by the 2020s. This effect diminished with inclusion of ozone precursor changes. When population growth is included, the projections of morbidity related to ozone are even larger. Conclusions The results of this analysis demonstrate that the use of regional climate and atmospheric chemistry models make possible the projection of local climate change health effects for specific age groups and specific disease outcomes – such as emergency department visits for asthma. Efforts should be made to improve on this type of modeling to inform local and wider-scale climate change mitigation and adaptation policy. PMID:21855738

  15. How Much Can the Total Aleatory Variability of Empirical Ground Motion Prediction Equations Be Reduced Using Physics-Based Earthquake Simulations?

    Science.gov (United States)

    Jordan, T. H.; Wang, F.; Graves, R. W.; Callaghan, S.; Olsen, K. B.; Cui, Y.; Milner, K. R.; Juve, G.; Vahi, K.; Yu, J.; Deelman, E.; Gill, D.; Maechling, P. J.

    2015-12-01

    Ground motion prediction equations (GMPEs) in common use predict the logarithmic intensity of ground shaking, lnY, as a deterministic value, lnYpred(x), conditioned on a set of explanatory variables x plus a normally distributed random variable with a standard deviation σT. The latter accounts for the unexplained variability in the ground motion data used to calibrate the GMPE and is typically 0.5-0.7 in natural log units. Reducing this residual or "aleatory" variability is a high priority for seismic hazard analysis, because the probabilities of exceedance at high Y values go up rapidly with σT. adding costs to the seismic design of critical facilities to account for the prediction uncertainty. However, attempts to decrease σT by incorporating more explanatory variables to the GMPEs have been largely unsuccessful (e.g., Strasser et al., SRL, 2009). An alternative is to employ physics-based earthquake simulations that properly account for source directivity, basin effects, directivity-basin coupling, and other 3D complexities. We have explored the theoretical limits of this approach through an analysis of large (> 108) ensembles of 3D synthetic seismograms generated for the Los Angeles region by SCEC's CyberShake project using the new tool of averaging-based factorization (ABF, Wang & Jordan, BSSA, 2014). The residual variance obtained by applying GMPEs to the CyberShake dataset matches the frequency-dependence of σT obtained for the GMPE calibration dataset. The ABF analysis allows us to partition this variance into uncorrelated components representing source, path, and site effects. We show that simulations can potentially reduce σT by about one-third, which could lower the exceedance probabilities for high hazard levels at fixed x by orders of magnitude. Realizing this gain in forecasting probability would have a broad impact on risk-reduction strategies, especially for critical facilities such as large dams, nuclear power plants, and energy transportation

  16. Assessment of Kalman filter bias-adjustment technique to improve the simulation of ground-level ozone over Spain.

    Science.gov (United States)

    Sicardi, V; Ortiz, J; Rincón, A; Jorba, O; Pay, M T; Gassó, S; Baldasano, J M

    2012-02-01

    The CALIOPE air quality modelling system has been used to diagnose ground level O(3) concentration for the year 2004, over the Iberian Peninsula. We investigate the improvement in the simulation of daily O(3) maximum by the use of a post-processing such as the Kalman filter bias-adjustment technique. The Kalman filter bias-adjustment technique is a recursive algorithm to optimally estimate bias-adjustment terms from previous measurements and model results. The bias-adjustment technique improved the simulation of daily O(3) maximum for the entire year and the all the stations considered over the whole domain. The corrected simulation presents improvements in statistical indicators such as correlation, root mean square error, mean bias, and gross error. After the post-processing the exceedances of O(3) concentration limits, as established by the European Directive 2008/50/CE, are better reproduced and the uncertainty of the modelling system, as established by the European Directive 2008/50/CE, is reduced from 20% to 7.5%. Such uncertainty in the model results is under the established EU limit of the 50%. Significant improvements in the O(3) timing and amplitude of the daily cycle are also observed after the post-processing. The systematic improvements in the O(3) maximum simulations suggest that the Kalman filter post-processing method is a suitable technique to reproduce accurate estimate of ground-level O(3) concentration. With this study we evince that the adjusted O(3) concentrations obtained after the post-process of the results from the CALIOPE system are a reliable means for real near time O(3) forecasts.

  17. Effect of sewage sludge on formation of acidic ground water at a reclaimed coal mine

    Science.gov (United States)

    Cravotta, C.A.

    1998-01-01

    Data on rock, ground water, vadose water, and vadose gas chemistry were collected for two years after sewage sludge was applied at a reclaimed surface coal mine in Pennsylvania to determine if surface-applied sludge is an effective barrier to oxygen influx, contributes metals and nutrients to ground water, and promotes the acidification of ground water. Acidity, sulfate, and metals concentrations were elevated in the ground water (6- to 21-m depth) from spoil relative to unmined rock because of active oxidation of pyrite and dissolution of aluminosilicate, carbonate, and Mn-Fe-oxide minerals in the spoil. Concentrations of acidity, sulfate, metals (Fe, Mn, Al, Cd, Cu, Cr, Ni, Zn), and nitrate, and abundances of iron-oxidizing bacteria were elevated in the ground water from sludge-treated spoil relative to untreated spoil having a similar mineral composition; however, gaseous and dissolved oxygen concentrations did not differ between the treatments. Abundances of iron-oxidizing bacteria in the ground water samples were positively correlated with concentrations of ammonia, nitrate, acidity, metals, and sulfate. Concentrations of metals in vadose water samples (iron-oxidizing bacteria, the oxidation of pyrite, and the acidification of ground water. Nevertheless, the overall effects on ground water chemistry from the sludge were small and probably short-lived relative to the effects from mining only.

  18. Discrete and continuum simulations of near-field ground motion from Source Physics Experiments (SPE) (Invited)

    Science.gov (United States)

    Ezzedine, S. M.; Vorobiev, O.; Herbold, E. B.; Glenn, L. A.; Antoun, T.

    2013-12-01

    algorithm. It is also suitable for evaluating the bounds of possible shear motion due to uncertainties in the joints distribution. Details of this uncertainty quantification study are presented in a separate abstract (Vorobiev, et.al). In the present work using both the continuum and the discrete approaches we study the effects of the surface spall, in-situ stress and joint orientation on the observed near-field motion. Three dimensional numerical simulations are performed for different burial depths and yields to investigate scalability of both radial and shear motions. The motion calculated in the near-field is then propagated into a far field. Results of the far field study are presented in an accompanied work (Pitarka, et al). This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  19. Dilution Effects on Two-Dimensional Heisenberg Antiferromagnets with Non-Magnetic Spin-Gapped Ground State

    OpenAIRE

    Yasuda, Chitoshi; Todo, Synge; Matsumoto, Munehisa; Takayama, Hajime

    2002-01-01

    Dilution effects on spin-1/2 quantum Heisenberg antiferromagnets with a non-magnetic spin-gapped ground state are studied by means of the qunatum Monte Carlo simulation. In the site-diluted system, an antiferromagnetic long-range order (AF-LRO) is induced at an infinitesimal concentration of dilution due to an effective coupling $\\tilde{J}_{mn}$ between induced magnetic moments. In the bond-diluted case, on the other hand, the AF-LRO is not induced up to a certain concentration of dilution du...

  20. Multi-body simulation of a canine hind limb: model development, experimental validation and calculation of ground reaction forces

    Directory of Open Access Journals (Sweden)

    Wefstaedt Patrick

    2009-11-01

    Full Text Available Abstract Background Among other causes the long-term result of hip prostheses in dogs is determined by aseptic loosening. A prevention of prosthesis complications can be achieved by an optimization of the tribological system which finally results in improved implant duration. In this context a computerized model for the calculation of hip joint loadings during different motions would be of benefit. In a first step in the development of such an inverse dynamic multi-body simulation (MBS- model we here present the setup of a canine hind limb model applicable for the calculation of ground reaction forces. Methods The anatomical geometries of the MBS-model have been established using computer tomography- (CT- and magnetic resonance imaging- (MRI- data. The CT-data were collected from the pelvis, femora, tibiae and pads of a mixed-breed adult dog. Geometric information about 22 muscles of the pelvic extremity of 4 mixed-breed adult dogs was determined using MRI. Kinematic and kinetic data obtained by motion analysis of a clinically healthy dog during a gait cycle (1 m/s on an instrumented treadmill were used to drive the model in the multi-body simulation. Results and Discussion As a result the vertical ground reaction forces (z-direction calculated by the MBS-system show a maximum deviation of 1.75%BW for the left and 4.65%BW for the right hind limb from the treadmill measurements. The calculated peak ground reaction forces in z- and y-direction were found to be comparable to the treadmill measurements, whereas the curve characteristics of the forces in y-direction were not in complete alignment. Conclusion In conclusion, it could be demonstrated that the developed MBS-model is suitable for simulating ground reaction forces of dogs during walking. In forthcoming investigations the model will be developed further for the calculation of forces and moments acting on the hip joint during different movements, which can be of help in context with the in

  1. Broadband Strong Ground Motion Simulation For a Potential Mw 7.1 Earthquake on The Enriquillo Fault in Haiti

    Science.gov (United States)

    Douilly, R.; Mavroeidis, G. P.; Calais, E.

    2015-12-01

    The devastating 2010 Haiti earthquake showed the need to be more vigilant toward mitigation for future earthquakes in the region. Previous studies have shown that this earthquake did not occur on the Enriquillo Fault, the main plate boundary fault running through the heavily populated Port-au-Prince region, but on the nearby and previously unknown Léogâne transpressional fault. Slip on that fault has increased stresses on the Enriquillo Fault mostly in the region closer to Port-au-Prince, the most populated city of the country. Here we investigate the ground shaking level in this region if a rupture similar to the Mw 7.0 2010 Haiti earthquake occurred on the Enriquillo fault. We use a finite element method and assumptions on regional stress to simulate low frequency dynamic rupture propagation for a 53 km long segment. We introduce some heterogeneity by creating two slip patches with shear traction 10% greater than the initial shear traction on the fault. The final slip distribution is similar in distribution and magnitude to previous finite fault inversions for the 2010 Haiti earthquake. The high-frequency ground motion components are calculated using the specific barrier model, and the hybrid synthetics are obtained by combining the low-frequencies (f 1Hz) from the stochastic simulation using matched filtering at a crossover frequency of 1 Hz. The average horizontal peak ground acceleration, computed at several sites of interest through Port-au-Prince, has a value of 0.35g. We also compute response spectra at those sites and compare them to the spectra from the microzonation study.

  2. Dust aerosol characterization and transport features based on combined ground-based, satellite and model-simulated data

    Science.gov (United States)

    Vijayakumar, K.; Devara, P. C. S.; Rao, S. Vijaya Bhaskara; Jayasankar, C. K.

    2016-06-01

    In this paper, we study aerosol characteristics over an urban station in Western India, during a dust event that occurred between 19 and 26 March 2012, with the help of ground-based and satellite measurements and model simulation data. The aerosol parameters are found to change significantly during dust events and they suggest dominance of coarse mode aerosols. The fine mode fraction, size distribution and single scattering albedo reveal that dust (natural) aerosols dominate the anthropogenic aerosols over the study region. Ground-based measurements show drastic reduction in visibility on the dust-laden day (22 March 2012). Additionally, HYSPLIT model and satellite daily data have been used to trace the source, path and spatial extent of dust storm events. Most of the dust aerosols, during the study period, travel from west-to-east pathway from source-to-sink region. Furthermore, aerosol vertical profiles from CALIPSO and synoptic meteorological parameters from ECMWF re-analysis data reveal a layer of thick dust extending from surface to an altitude of about 4 km, and decrease in temperature and increase in specific humidity, respectively. The aerosol radiative forcing calculations indicate more cooling at the surface and warming in the atmosphere during dust event. The results of satellite observations are found to have good consistency with ground-based air quality measurements. Synthesis of satellite data integrated with ground-based observations, supplemented by model analysis, is found to be a promising technique for improved understanding of dust storm phenomenon and its impact on regional climate.

  3. Aerodynamics of flapping insect wing in inclined stroke plane hovering with ground effect

    Science.gov (United States)

    Gowda v, Krishne; Vengadesan, S.

    2014-11-01

    This work presents the time-varying aerodynamic forces and the unsteady flow structures of flapping insect wing in inclined stroke plane hovering with ground effect. Two-dimensional dragonfly model wing is chosen and the incompressible Navier-Stokes equations are solved numerically by using immersed boundary method. The main objective of the present work is to analyze the ground effect on the unsteady forces and vortical structures for the inclined stroke plane motions. We also investigate the influences of kinematics parameters such as Reynolds number (Re), stroke amplitude, wing rotational timing, for various distances between the airfoil and the ground. The effects of aforementioned parameters together with ground effect, on the stroke averaged force coefficients and regimes of force behavior are similar in both normal (horizontal) and inclined stroke plane motions. However, the evolution of the vortex structures which produces the effects are entirely different.

  4. Simulation: an effective pedagogical approach for nursing?

    Science.gov (United States)

    Berragan, Liz

    2011-10-01

    Simulation features strongly within the undergraduate nursing curriculum for many Universities. It provides a variety of opportunities for students as they develop their clinical nursing skills. The nursing literature highlights the potential of this approach and the positive opportunities afforded to students in terms of developing competence and confidence. However, much of this literature focuses upon the more operational concerns of simulation. This paper reflects upon the evolution of simulation in nurse education. It considers the theoretical positioning and understanding of simulation as a teaching and learning approach for undergraduate nursing skills development. The work of Vygotsky (1978) and Lave and Wenger (1991) are highlighted in order to begin to explore the theoretical basis of simulation as an effective pedagogical approach for nurse education today, enabling students to learn to be nurses. Copyright © 2011 Elsevier Ltd. All rights reserved.

  5. Audio-haptic physically-based simulation of walking on different grounds

    DEFF Research Database (Denmark)

    Turchet, Luca; Nordahl, Rolf; Serafin, Stefania;

    2010-01-01

    We describe a system which simulates in realtime the auditory and haptic sensations of walking on different surfaces. The system is based on a pair of sandals enhanced with pressure sensors and actuators. The pressure sensors detect the interaction force during walking, and control several...

  6. Contemporary virtual reality laparoscopy simulators: quicksand or solid grounds for assessing surgical trainees?

    NARCIS (Netherlands)

    A.S. Thijssen; M.P. Schijven

    2010-01-01

    BACKGROUND: A demand for safe, efficient laparoscopic training tools has prompted the introduction of virtual reality (VR) laparoscopic simulators, which might be used for performance assessment. The purpose of this review is to determine the value of VR metrics in laparoscopic skills assessment. DA

  7. Effect of Antioxidants on DC Tree and Grounded DC Tree in XLPE

    Science.gov (United States)

    Kawanami, Hiroshi; Komatsu, Isao; Sekii, Yasuo; Saito, Mitsugu; Sugi, Kazuyuki

    To study the effects of antioxidants on the initiation of the DC tree and the grounded DC tree, experiments were conducted using XLPE specimens containing phenolic and sulfur type antioxidants. Experimental results showed that sulfur type antioxidants in XLPE have the effect of increasing inception voltages of both the DC tree and the grounded DC tree. Based on results of those experiments, the mechanism of increase in the inception voltage of the DC tree and the grounded DC tree by antioxidants was examined along with the mechanism of polarity effects on those trees. Results showed a promotional effect of charge injection from a needle electrode by antioxidants, which are responsible for the increased inception voltages of the DC tree. Charge trapping by antioxidants explains the increase of inception voltages of the grounded DC tree.

  8. Effects of Color Reversal of Figure and Ground Drawing Materials on Drawing Performance

    Science.gov (United States)

    May, Deborah C.

    1978-01-01

    Studied were the effects of reversing the color of white and black figure and ground drawings on Goodenough-Harris Drawing Test performance of 21 cerebral palsied and 21 normal children (all 5 to 18 years old). (Author/SBH)

  9. Soil moisture characterization of the Valencia anchor station. Ground, aircraft measurements and simulations

    DEFF Research Database (Denmark)

    Lopez-Baeza, E; Antolin, M C; Balling, Jan E.

    2009-01-01

    In the framework of ESA SMOS Mission, the Valencia Anchor Station (VAS) has been selected as a core validation site. Its reasonable homogeneous characteristics make it appropriate to undertake the validation of SMOS Level 2 land products before attempting other more complex areas. Close to SMOS....... For the rehearsal activity which successfully took place in April - May 2008, a control area of 10 × 10 km2 was chosen at the VAS study area where a network of ground soil moisture (SM) measuring stations is being set up based on an original definition of homogeneous physio-hydrological units attending to climatic...... of the following instruments: (i) L-band EMIRAD radiometer (Technical University of Denmark, TUD), (ii) L-band HUT-2D imaging interferometric radiometer (TKK), (iii) PARIS GPS reflectrometry system (Institute for Space Studies of Catalonia, IEEC), (iv) IR sensor (Finnish Institute of Maritime Research, FIMR...

  10. Numerical simulation of the pollution formed by exhaust jets at the ground running procedure

    Science.gov (United States)

    Korotaeva, T. A.; Turchinovich, A. O.

    2016-10-01

    The paper presents an approach that is new for aviation-related ecology. The approach allows defining spatial distribution of pollutant concentrations released at engine ground running procedure (GRP) using full gas-dynamic models. For the first time such a task is modeled in three-dimensional approximation in the framework of the numerical solution of the Navier-Stokes equations with taking into account a kinetic model of interaction between the components of engine exhaust and air. The complex pattern of gas-dynamic flow that occurs at the flow around an aircraft with the jet exhausts that interact with each other, air, jet blast deflector (JBD), and surface of the airplane has been studied in the present work. The numerical technique developed for calculating the concentrations of pollutants produced at the GRP stage permits to define level, character, and area of contamination more reliable and increase accuracy in definition of sanitary protection zones.

  11. Horizontal Air-Ground Heat Exchanger Performance and Humidity Simulation by Computational Fluid Dynamic Analysis

    Directory of Open Access Journals (Sweden)

    Paolo Maria Congedo

    2016-11-01

    Full Text Available Improving energy efficiency in buildings and promoting renewables are key objectives of European energy policies. Several technological measures are being developed to enhance the energy performance of buildings. Among these, geothermal systems present a huge potential to reduce energy consumption for mechanical ventilation and cooling, but their behavior depending on varying parameters, boundary and climatic conditions is not fully established. In this paper a horizontal air-ground heat exchanger (HAGHE system is studied by the development of a computational fluid dynamics (CFD model. Summer and winter conditions representative of the Mediterranean climate are analyzed to evaluate operation and thermal performance differences. A particular focus is given to humidity variations as this parameter has a major impact on indoor air quality and comfort. Results show the benefits that HAGHE systems can provide in reducing energy consumption in all seasons, in summer when free-cooling can be implemented avoiding post air treatment using heat pumps.

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

    Directory of Open Access Journals (Sweden)

    A. S. ABDULKAREEM

    2005-01-01

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

  13. The effect of cinnamon bark (Cinnamomum burmanii) essential oil microcapsules on vacuumed ground beef quality

    Science.gov (United States)

    Brilliana, I. N.; Manuhara, G. J.; Utami, R.; Khasanah, L. U.

    2017-04-01

    Ground beef has a short shelf life because it is susceptible to damage due to microbial contamination and lipid oxidation. So some sort of preservation method such as refrigerated storage, vacuum packaging or natural preservative addition is needed to extend the shelf life of ground beef. A natural preservative that can be used as a food preservative is the cinnamon bark (Cinnamomum burmanii) essential oil microcapsules. The aim of the research was to determine the influence of a cinnamon bark essential oil microcapsules (0%;0.5% and 1% w/w of the ground beef) on the Total Plate Count (TPC), Thiobarbituric Acid (TBA), pH and color of ground beef during refrigerated storage (4±1°C). The result showed that cinnamon bark essential oil microcapsules affected the TPC, TBA, pH and color of ground beef. The addition of the cinnamon bark essential oil microcapsules on ground beef can inhibit microbial growth, inhibit lipid oxidation, inhibit discoloration and lowering pH of fresh ground beef during refrigerated storage compared to the control sample. The higher of the microcapsules were added, the higher the inhibition of microbial growth, lipid oxidation and discoloration of ground beef, indicating better preservation effects.

  14. An Empirically grounded Agent Based simulator for the Air Traffic Management in the SESAR scenario

    CERN Document Server

    Gurtner, Gérald; Ducci, Marco; Miccichè, Salvatore

    2016-01-01

    In this paper we present a simulator allowing to perform policy experiments relative to the air traffic management. Different SESAR solutions can be implemented in the model to see the reaction of the different stakeholders as well as other relevant metrics (delays, safety, etc). The model describes both the strategic phase associated to the planning of the flight trajectories and the tactical modifications occurring in the en-route phase. An implementation of the model is available as open-source and freely accessible by any user. More specifically, different procedures related to business trajectories and free-routing are tested and we illustrate the capabilities of the model on airspace implementing these concepts. After performing numerical simulations with the model, we show that in a free-routing scenario the controllers perform less operations although they are dispersed over a larger portion of the airspace. This can potentially increase the complexity of conflict detection and resolution for controll...

  15. Validation of ground-motion simulations for historical events using SDoF systems

    Science.gov (United States)

    Galasso, C.; Zareian, F.; Iervolino, I.; Graves, R.W.

    2012-01-01

    The study presented in this paper is among the first in a series of studies toward the engineering validation of the hybrid broadband ground‐motion simulation methodology by Graves and Pitarka (2010). This paper provides a statistical comparison between seismic demands of single degree of freedom (SDoF) systems subjected to past events using simulations and actual recordings. A number of SDoF systems are selected considering the following: (1) 16 oscillation periods between 0.1 and 6 s; (2) elastic case and four nonlinearity levels, from mildly inelastic to severely inelastic systems; and (3) two hysteretic behaviors, in particular, nondegrading–nonevolutionary and degrading–evolutionary. Demand spectra are derived in terms of peak and cyclic response, as well as their statistics for four historical earthquakes: 1979 Mw 6.5 Imperial Valley, 1989 Mw 6.8 Loma Prieta, 1992 Mw 7.2 Landers, and 1994 Mw 6.7 Northridge.

  16. Performance of Irikura's Recipe Rupture Model Generator in Earthquake Ground Motion Simulations as Implemented in the Graves and Pitarka Hybrid Approach.

    Energy Technology Data Exchange (ETDEWEB)

    Pitarka, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-11-22

    We analyzed the performance of the Irikura and Miyake (2011) (IM2011) asperity-­ based kinematic rupture model generator, as implemented in the hybrid broadband ground-­motion simulation methodology of Graves and Pitarka (2010), for simulating ground motion from crustal earthquakes of intermediate size. The primary objective of our study is to investigate the transportability of IM2011 into the framework used by the Southern California Earthquake Center broadband simulation platform. In our analysis, we performed broadband (0 -­ 20Hz) ground motion simulations for a suite of M6.7 crustal scenario earthquakes in a hard rock seismic velocity structure using rupture models produced with both IM2011 and the rupture generation method of Graves and Pitarka (2016) (GP2016). The level of simulated ground motions for the two approaches compare favorably with median estimates obtained from the 2014 Next Generation Attenuation-­West2 Project (NGA-­West2) ground-­motion prediction equations (GMPEs) over the frequency band 0.1–10 Hz and for distances out to 22 km from the fault. We also found that, compared to GP2016, IM2011 generates ground motion with larger variability, particularly at near-­fault distances (<12km) and at long periods (>1s). For this specific scenario, the largest systematic difference in ground motion level for the two approaches occurs in the period band 1 – 3 sec where the IM2011 motions are about 20 – 30% lower than those for GP2016. We found that increasing the rupture speed by 20% on the asperities in IM2011 produced ground motions in the 1 – 3 second bandwidth that are in much closer agreement with the GMPE medians and similar to those obtained with GP2016. The potential implications of this modification for other rupture mechanisms and magnitudes are not yet fully understood, and this topic is the subject of ongoing study.

  17. Dynamical response of the Galileo Galilei on the ground rotor to test the equivalence principle: Theory, simulation, and experiment. I. The normal modes

    Science.gov (United States)

    Comandi, G. L.; Chiofalo, M. L.; Toncelli, R.; Bramanti, D.; Polacco, E.; Nobili, A. M.

    2006-03-01

    Recent theoretical work suggests that violation of the equivalence principle might be revealed in a measurement of the fractional differential acceleration η between two test bodies—of different compositions, falling in the gravitational field of a source mass—if the measurement is made to the level of η ≃10-13 or better. This being within the reach of ground based experiments gives them a new impetus. However, while slowly rotating torsion balances in ground laboratories are close to reaching this level, only an experiment performed in a low orbit around the Earth is likely to provide a much better accuracy. We report on the progress made with the "Galileo Galilei on the ground" (GGG) experiment, which aims to compete with torsion balances using an instrument design also capable of being converted into a much higher sensitivity space test. In the present and following articles (Part I and Part II), we demonstrate that the dynamical response of the GGG differential accelerometer set into supercritical rotation—in particular, its normal modes (Part I) and rejection of common mode effects (Part II)—can be predicted by means of a simple but effective model that embodies all the relevant physics. Analytical solutions are obtained under special limits, which provide the theoretical understanding. A simulation environment is set up, obtaining a quantitative agreement with the available experimental data on the frequencies of the normal modes and on the whirling behavior. This is a needed and reliable tool for controlling and separating perturbative effects from the expected signal, as well as for planning the optimization of the apparatus.

  18. Preliminary results of sequential monitoring of simulated clandestine graves in Colombia, South America, using ground penetrating radar and botany.

    Science.gov (United States)

    Molina, Carlos Martin; Pringle, Jamie K; Saumett, Miguel; Hernández, Orlando

    2015-03-01

    In most Latin American countries there are significant numbers of missing people and forced disappearances, 68,000 alone currently in Colombia. Successful detection of shallow buried human remains by forensic search teams is difficult in varying terrain and climates. This research has created three simulated clandestine burial styles at two different depths commonly encountered in Latin America to gain knowledge of optimum forensic geophysics detection techniques. Repeated monitoring of the graves post-burial was undertaken by ground penetrating radar. Radar survey 2D profile results show reasonable detection of ½ clothed pig cadavers up to 19 weeks of burial, with decreasing confidence after this time. Simulated burials using skeletonized human remains were not able to be imaged after 19 weeks of burial, with beheaded and burnt human remains not being able to be detected throughout the survey period. Horizontal radar time slices showed good early results up to 19 weeks of burial as more area was covered and bi-directional surveys were collected, but these decreased in amplitude over time. Deeper burials were all harder to image than shallower ones. Analysis of excavated soil found soil moisture content almost double compared to those reported from temperate climate studies. Vegetation variations over the simulated graves were also noted which would provide promising indicators for grave detection.

  19. Municipality Level Simulations of Dengue Fever Incidence in Puerto Rico Using Ground Based and Remotely Sensed Climate Data

    Science.gov (United States)

    Quattrochi, Dale A.; Morin, Cory

    2015-01-01

    Dengue fever (DF) is caused by a virus transmitted between humans and Aedes genus mosquitoes through blood feeding. In recent decades incidence of the disease has drastically increased in the tropical Americas, culminating with the Pan American outbreak in 2010 which resulted in 1.7 million reported cases. In Puerto Rico dengue is endemic, however, there is significant inter-annual, intraannual, and spatial variability in case loads. Variability in climate and the environment, herd immunity and virus genetics, and demographic characteristics may all contribute to differing patterns of transmission both spatially and temporally. Knowledge of climate influences on dengue incidence could facilitate development of early warning systems allowing public health workers to implement appropriate transmission intervention strategies. In this study, we simulate dengue incidence in several municipalities in Puerto Rico using population and meteorological data derived from ground based stations and remote sensing instruments. This data was used to drive a process based model of vector population development and virus transmission. Model parameter values for container composition, vector characteristics, and incubation period were chosen by employing a Monte Carlo approach. Multiple simulations were performed for each municipality and the results were compared with reported dengue cases. The best performing simulations were retained and their parameter values and meteorological input were compared between years and municipalities. Parameter values varied by municipality and year illustrating the complexity and sensitivity of the disease system. Local characteristics including the natural and built environment impact transmission dynamics and produce varying responses to meteorological conditions.

  20. Establishment and Simulation of an Arc Model for the Faults in the Neutral Point Non-effectively Grounding System%中性点非有效接地系统故障电弧模型的搭建与仿真

    Institute of Scientific and Technical Information of China (English)

    金海望; 郑晓辉; 夏岩松; 王强; 田霖; 张亚晨; 徐璐; 高立柱

    2015-01-01

    When studying arc grounding fault of the distribution network,breaker switching arc and electrical characters of the arc furnace,most scholars use three arc models of constant resistance,Cassie and Mayr,all of which are one-sided.Combination of Cassie and Mayr models may complement each other.This article combines those two arc models on the ATP-EMTP platform and sets parameters in a reasonable way.Through emulation of the neutral point non-effectively grounded 10 kV distribution network,it studies and analyzes the voltage distribution,zero crossing and volt-ampere characteristics of the arc,and proves that this arc model can correctly reflect the fault arc characteristics of the neutral point non-effectively grounded distribution network.%在研究配电网的电弧接地故障、断路器投切电弧及电弧炉电气特性时,多数学者通常使用恒电阻、Cassie、Mayr 电弧模型,三者都具有片面性,将 Cassie 与 Mayr 两个电弧模型结合使用可以达到互补。在 ATP -EMTP 平台下将两种电弧模型进行组合搭建,并合理设置参数,通过在中性点非有效接地10 kV 配电网下的仿真,研究分析了电弧的电压分布、过零点、伏安特性,证明该电弧模型可正确反映中性点非有效接地配电网故障电弧特性。

  1. Effects of gully terrain on stress field distribution and ground pressure behavior in shallow seam mining

    Institute of Scientific and Technical Information of China (English)

    Li Jianwei; Liu Changyou; Zhao Tong

    2016-01-01

    This study proposes a novel approach to study stress field distribution and overlying ground pressure behavior in shallow seam mining in gully terrain. This approach combines numerical simulations and field tests based on the conditions of gully terrain in the Chuancao Gedan Mine. The effects of gully ter-rain on the in situ stress field of coal beds can be identified by the ratio of self-weight stress to vertical stress (g) at the location corresponding to the maximum vertical stress. Based on the function g=f(h), the effect of gully terrain on the stress field of overlying strata of the entire field can be characterized as a significantly affected area, moderately affected area, or non-affected area. Working face 6106 in the Chuancao Gedan Mine had a coal bed depth<80 m and was located in what was identified as a signifi-cantly affected area. Hence, mining may cause sliding of the gully slope and increased loading (including significant dynamic loading) on the roof strata. Field tests suggest that significant dynamic pressures were observed at the body and foot of the gully slope, and that dynamic loadings were observed upslope of the working face expansion, provided that the expanding direction of the working face is parallel to the gully.

  2. Schemed Power-augmented Flow for Wing-in-ground Effect Craft in Cruise

    Institute of Scientific and Technical Information of China (English)

    YANG Wei; YANG Zhigang

    2011-01-01

    To provide detailed insight into schemed power-angmented flow for wing-in-ground effect (WIG) craft in view of the concept of cruising with power assistance, this paper presents a numerical study.The engine installed before the wing for power-augmented flow is replaced by a simplified engine model in the simulations, and is considered to be equipped with a thrust vector nozzle.Flow features with different deflected nozzle angles are studied.Comparisons are made on aerodynamics to evaluate performance of power-augmented ram (PAR) modes in cruise.Considerable schemes of power-augmented flow in cruise are described.The air blown from the PAR engine accelerates the flow around wing and a high-speed attached flow near the trailing edge is recorded for certain deflected nozzle angles.This effect takes place and therefore the separation is prevented not only at the trailing edge but also on the whole upper side.The realization of suction varies with PAR modes.It is also found that scheme of blowing air under the wing for PAR engine is aerodynamically not efficient in cruise.The power-augmented flow is extremely complicated.The numerical results give clear depiction of the flow.Optimal scheme of power-augmented flow with respect to the craft in cruise depends on the specific engines and the flight regimes.

  3. Validation of the use of organic acids and acidified sodium chlorite to reduce Escherichia coli O157 and Salmonella typhimurium in beef trim and ground beef in a simulated processing environment.

    Science.gov (United States)

    Harris, K; Miller, M F; Loneragan, G H; Brashears, M M

    2006-08-01

    A study was conducted to determine if acidified sodium chlorite (1,200 ppm) and acetic and lactic acids (2 and 4%) were effective in reducing foodborne pathogens in beef trim prior to grinding in a simulated processing environment. The reduction of Salmonella Typhimurium and Escherichia coli O157:H7 at high (4.0 log CFU/g) and low (1.0 log CFU/g) inoculation doses was evaluated at various processing steps, including the following: (i) in trim just after treatment application, (ii) in ground beef just after grinding, (iii) in ground beef 24 h after refrigerated storage, (iv) in ground beef 5 days after refrigerated storage, and (v) in ground beef 30 days after frozen storage. All antimicrobial treatments reduced the pathogens on the trim inoculated with the lower inoculation dose to nondetectable numbers in the trim and in the ground beef. There were significant reductions of both pathogens in the trim and in the ground beef inoculated with the high inoculation doses. On the trim itself, E. coli O157:H7 and Salmonella Typhimurium were reduced by 1.5 to 2.0 log cycles, with no differences among all treatments. In the ground beef, the organic acids were more effective in reducing both pathogens than the acidified sodium chlorite immediately after grinding, but after 1 day of storage, there were no differences among treatments. Overall, in the ground beef, there was a 2.5-log reduction of E. coli O157:H7 and a 1.5-log reduction of Salmonella Typhimurium that was sustained over time in refrigerated and frozen storage. Very few sensory differences between the control samples and the treated samples were detected by a consumer panel. Thus, antimicrobial treatments did not cause serious adverse sensory changes. Use of these antimicrobial treatments can be a promising intervention available to ground beef processors who currently have few interventions in their process.

  4. The Italian Project S2 - Task 4:Near-fault earthquake ground motion simulation in the Sulmona alluvial basin

    Science.gov (United States)

    Stupazzini, M.; Smerzini, C.; Cauzzi, C.; Faccioli, E.; Galadini, F.; Gori, S.

    2009-04-01

    Recently the Italian Department of Civil Protection (DPC), in cooperation with Istituto Nazionale di Geofisica e Vulcanologia (INGV) has promoted the 'S2' research project (http://nuovoprogettoesse2.stru.polimi.it/) aimed at the design, testing and application of an open-source code for seismic hazard assessment (SHA). The tool envisaged will likely differ in several important respects from an existing international initiative (Open SHA, Field et al., 2003). In particular, while "the OpenSHA collaboration model envisions scientists developing their own attenuation relationships and earthquake rupture forecasts, which they will deploy and maintain in their own systems", the main purpose of S2 project is to provide a flexible computational tool for SHA, primarily suited for the needs of DPC, which not necessarily are scientific needs. Within S2, a crucial issue is to make alternative approaches available to quantify the ground motion, with emphasis on the near field region. The SHA architecture envisaged will allow for the use of ground motion descriptions other than those yielded by empirical attenuation equations, for instance user generated motions provided by deterministic source and wave propagation simulations. In this contribution, after a brief presentation of Project S2, we intend to illustrate some preliminary 3D scenario simulations performed in the alluvial basin of Sulmona (Central Italy), as an example of the type of descriptions that can be handled in the future SHA architecture. In detail, we selected some seismogenic sources (from the DISS database), believed to be responsible for a number of destructive historical earthquakes, and derive from them a family of simplified geometrical and mechanical source models spanning across a reasonable range of parameters, so that the extent of the main uncertainties can be covered. Then, purely deterministic (for frequencies Element (SE) method, extensively published by Faccioli and his co-workers, and

  5. Ground-Wave Propagation Effects on Transmission Lines through Error Images

    Directory of Open Access Journals (Sweden)

    Uribe-Campos Felipe Alejandro

    2014-07-01

    Full Text Available Electromagnetic transient calculation of overhead transmission lines is strongly influenced by the natural resistivity of the ground. This varies from 1-10K (Ω·m depending on several media factors and on the physical composition of the ground. The accuracy on the calculation of a system transient response depends in part in the ground return model, which should consider the line geometry, the electrical resistivity and the frequency dependence of the power source. Up to date, there are only a few reports on the specialized literature about analyzing the effects produced by the presence of an imperfectly conducting ground of transmission lines in a transient state. A broad range analysis of three of the most often used ground-return models for calculating electromagnetic transients of overhead transmission lines is performed in this paper. The behavior of modal propagation in ground is analyzed here into effects of first and second order. Finally, a numerical tool based on relative error images is proposed in this paper as an aid for the analyst engineer to estimate the incurred error by using approximate ground-return models when calculating transients of overhead transmission lines.

  6. Sensitivity of Distributed Hydrologic Simulations to Ground and Satellite Based Rainfall Products

    OpenAIRE

    Singaiah Chintalapudi; Hatim O. Sharif; Hongjie Xie

    2014-01-01

    In this study, seven precipitation products (rain gauges, NEXRAD MPE, PERSIANN 0.25 degree, PERSIANN CCS-3hr, PERSIANN CCS-1hr, TRMM 3B42V7, and CMORPH) were used to force a physically-based distributed hydrologic model. The model was driven by these products to simulate the hydrologic response of a 1232 km2 watershed in the Guadalupe River basin, Texas. Storm events in 2007 were used to analyze the precipitation products. Comparison with rain gauge observations reveals that there were signif...

  7. Sensitivity of Distributed Hydrologic Simulations to Ground and Satellite Based Rainfall Products

    OpenAIRE

    Singaiah Chintalapudi; Hatim O. Sharif; Hongjie Xie

    2014-01-01

    In this study, seven precipitation products (rain gauges, NEXRAD MPE, PERSIANN 0.25 degree, PERSIANN CCS-3hr, PERSIANN CCS-1hr, TRMM 3B42V7, and CMORPH) were used to force a physically-based distributed hydrologic model. The model was driven by these products to simulate the hydrologic response of a 1232 km2 watershed in the Guadalupe River basin, Texas. Storm events in 2007 were used to analyze the precipitation products. Comparison with rain gauge observations reveals that there were signif...

  8. Real-Time and High-Fidelity Simulation Environment for Autonomous Ground Vehicle Dynamics

    Science.gov (United States)

    2013-08-01

    was rendered in OpenGL . Urban Environment The environment consisted of a 3D mesh model of a city. The mesh was created using a commercial tool...system. We rendered the 3D scene (in OpenGL ) and read back the depth buffer in a raster that matched the raster characteristics of a typical LIDAR...configure the simulation. Visualization is done using custom 3D graphics software based on OGRE and OpenGL . The software runs on a standard Linux

  9. Improvement of ground granulated blast furnace slag on stabilization/solidification of simulated mercury-doped wastes in chemically bonded phosphate ceramics.

    Science.gov (United States)

    Liu, Zhongzhe; Qian, Guangren; Zhou, Jizhi; Li, Chuanhua; Xu, Yunfeng; Qin, Zhe

    2008-08-30

    This paper investigated the effectiveness of (ground granulated blast furnace slag) GGBFS-added chemically bonded phosphate ceramic (CBPC) matrix on the stabilization/solidification (S/S) of mercury chloride and simulated mercury-bearing light bulbs (SMLB). The results showed that the maximal compressive strength was achieved when 15% and 10% ground GGBFS was added for HgCl(2)-doped and SMLB-doped CBPC matrices, respectively. The S/S performances of GGBFS-added matrices were significantly better than non-additive matrices. As pore size was reduced, the leaching concentration of Hg(2+) from GGBFS-added CBPC matrix could be reduced from 697 microg/L to about 3 microg/L when treating HgCl(2). Meanwhile, the main hydrating product of GGBFS-added matrices was still MgKPO(4).6H(2)O. The improvement of S/S effectiveness was mainly due to physical filling of fine GGBFS particles and microencapsulation of chemical cementing gel.

  10. Evaluation of Radar Vegetation Indices for Vegetation Water Content Estimation Using Data from a Ground-Based SMAP Simulator

    Science.gov (United States)

    Srivastava, Prashant K.; O'Neill, Peggy; Cosh, Michael; Lang, Roger; Joseph, Alicia

    2015-01-01

    Vegetation water content (VWC) is an important component of microwave soil moisture retrieval algorithms. This paper aims to estimate VWC using L band active and passive radar/radiometer datasets obtained from a NASA ground-based Soil Moisture Active Passive (SMAP) simulator known as ComRAD (Combined Radar/Radiometer). Several approaches to derive vegetation information from radar and radiometer data such as HH, HV, VV, Microwave Polarization Difference Index (MPDI), HH/VV ratio, HV/(HH+VV), HV/(HH+HV+VV) and Radar Vegetation Index (RVI) are tested for VWC estimation through a generalized linear model (GLM). The overall analysis indicates that HV radar backscattering could be used for VWC content estimation with highest performance followed by HH, VV, MPDI, RVI, and other ratios.

  11. Wear simulation effects on overdenture stud attachments.

    Science.gov (United States)

    Rutkunas, Vygandas; Mizutani, Hiroshi; Takahashi, Hidekazu; Iwasaki, Naohiko

    2011-01-01

    The aim of this study was to evaluate wear effects on overdenture resilient attachments. Six commercially available attachments were investigated: ERA orange and white (EO and EW), Locator pink, white and blue (LRP, LRW and LRB) and OP anchor (OP). Five specimens were used for wear simulation while other two specimens served as controls. Fifteen thousands insertion-removal cycles were simulated. Dimensional changes and surface characteristics were evaluated using light microscopy and SEM, respectively. Sudden decrease of retentive force was characteristic for EO and EW attachments. Retentive force of Locator attachments fluctuated throughout the wear simulation period. Dimensional changes and surface wear was more expressed on plastic cores than on plastic rings of attachment males. Based on SEM analysis, some of the specimens obtained smoother surface after wear simulation. Mechanism of retention loss of resilient overdenture attachments can be only partially explained by dimensional changes and surface alterations.

  12. Recalibration of a ground-water flow model of the Mississippi River Valley alluvial aquifer of northeastern Arkansas, 1918-1998, with simulations of water levels caused by projected ground-water withdrawals through 2049

    Science.gov (United States)

    Reed, Thomas B.

    2003-01-01

    A digital model of the Mississippi River Valley alluvial aquifer in eastern Arkansas was used to simulate ground-water flow for the period from 1918 to 2049. The model results were used to evaluate effects on water levels caused by demand for ground water from the alluvial aquifer, which has increased steadily for the last 40 years. The model results showed that water currently (1998) is being withdrawn from the aquifer at rates greater than what can be sustained for the long term. The saturated thickness of the alluvial aquifer has been reduced in some areas resulting in dry wells, degraded water quality, decreased water availability, increased pumping costs, and lower well yields. The model simulated the aquifer from a line just north of the Arkansas-Missouri border to south of the Arkansas River and on the east from the Mississippi River westward to the less permeable geologic units of Paleozoic age. The model consists of 2 layers, a grid of 184 rows by 156 columns, and comprises 14,118 active cells each measuring 1 mile on a side. It simulates time periods from 1918 to 1998 along with further time periods to 2049 testing different pumping scenarios. Model flux boundary conditions were specified for rivers, general head boundaries along parts of the western side of the model and parts of Crowleys Ridge, and a specified head boundary across the aquifer further north in Missouri. Model calibration was conducted for observed water levels for the years 1972, 1982, 1992, and 1998. The average absolute residual was 4.69 feet and the root-mean square error was 6.04 feet for the hydraulic head observations for 1998. Hydraulic-conductivity values obtained during the calibration process were 230 feet per day for the upper layer and ranged from 230 to 730 feet per day for the lower layer with the maximum mean for the combined aquifer of 480 feet per day. Specific yield values were 0.30 throughout the model and specific storage values were 0.000001 inverse-feet throughout

  13. Experimental quantum key distribution with simulated ground-to-satellite photon losses and processing limitations

    Science.gov (United States)

    Bourgoin, Jean-Philippe; Gigov, Nikolay; Higgins, Brendon L.; Yan, Zhizhong; Meyer-Scott, Evan; Khandani, Amir K.; Lütkenhaus, Norbert; Jennewein, Thomas

    2015-11-01

    Quantum key distribution (QKD) has the potential to improve communications security by offering cryptographic keys whose security relies on the fundamental properties of quantum physics. The use of a trusted quantum receiver on an orbiting satellite is the most practical near-term solution to the challenge of achieving long-distance (global-scale) QKD, currently limited to a few hundred kilometers on the ground. This scenario presents unique challenges, such as high photon losses and restricted classical data transmission and processing power due to the limitations of a typical satellite platform. Here we demonstrate the feasibility of such a system by implementing a QKD protocol, with optical transmission and full post-processing, in the high-loss regime using minimized computing hardware at the receiver. Employing weak coherent pulses with decoy states, we demonstrate the production of secure key bits at up to 56.5 dB of photon loss. We further illustrate the feasibility of a satellite uplink by generating a secure key while experimentally emulating the varying losses predicted for realistic low-Earth-orbit satellite passes at 600 km altitude. With a 76 MHz source and including finite-size analysis, we extract 3374 bits of a secure key from the best pass. We also illustrate the potential benefit of combining multiple passes together: while one suboptimal "upper-quartile" pass produces no finite-sized key with our source, the combination of three such passes allows us to extract 165 bits of a secure key. Alternatively, we find that by increasing the signal rate to 300 MHz it would be possible to extract 21 570 bits of a secure finite-sized key in just a single upper-quartile pass.

  14. Vertical profiling of atmospheric refractivity using GPS STD data from a single ground-based station: Simulations and applications

    Science.gov (United States)

    Zus, F.; Dick, G.; Heise, S.; Wickert, J.; Ramatschi, M.

    2013-12-01

    We developed a ray-tracing operator to compute the signal travel time delay due to the neutral atmosphere, known as Slant Total Delay (STD), between a GPS satellite and a ground-based receiving station. Having developed a rapid and precise forward operator we constructed the tangent-linear (adjoint) operator to estimate refractivity in the vicinity of a single station. The refractivity retrievals potentially complement refractivity retrievals from radio occultation data and can be considered a valuable input for Numerical Weather Prediction. In a first experiment (simulation) we study the feasibility for vertical profiling of refractivity using STDs from a single station. The simulation cycle consists of the computation of STDs given a refractivity profile, the addition of noise to mimic observation errors and the retrieval of a refractivity profile from the artificial STDs by a non-linear least-square analysis. Clearly, besides the noise level, the elevation range plays an important role regarding the quality of the refractivity retrieval; near-horizon STDs corrupted by noise allow a significantly better refractivity retrieval than STDs close to the zenith without any noise. The simulation study suggests that near-horizon STDs provide additional information when compared to Zenith Total Delays (ZTDs). In a second experiment (application) we replace the artificial STDs in the simulation by STDs retrieved from GPS phase-observations. The procedure is repeated station-by-station for 200 stations in Germany. We do not find a significant benefit from STDs over ZTDs in the retrieved refractivity profile since near-horizon STDs are rarely available and representative errors due to asymmetry are non-negligable. We attempt to mitigate the latter problem by the additional estimation of horizontal gradients, and indeed, we find strong evidence that STDs retrieved from GPS phase-observations contain asymmetric information. The former problem still poses a serious limitation

  15. Simulation of polar atmospheric microwave and sub-millimetre spectra for characterizing potential new ground-based observations

    Science.gov (United States)

    Newnham, David; Turner, Emma; Ford, George; Pumphrey, Hugh; Withington, Stafford

    2016-04-01

    Advanced detector technologies from the fields of astronomy and telecommunications are offering the potential to address key atmospheric science challenges with new instrumental methods. Adoption of these technologies in ground-based passive microwave and sub-millimetre radiometry could allow new measurements of chemical species and winds in the polar middle atmosphere for verifying meteorological data-sets and atmospheric models. A site study to assess the feasibility of new polar observations is performed by simulating the downwelling clear-sky submillimetre spectrum over 10-2000 GHz (30 mm to 150 microns) at two Arctic and two Antarctic locations under different seasonal and diurnal conditions. Vertical profiles for temperature, pressure and 28 atmospheric gases are constructed by combining radiosonde, meteorological reanalysis, and atmospheric chemistry model data. The sensitivity of the simulated spectra to the choice of water vapour continuum model and spectroscopic line database is explored. For the atmospheric trace species hypobromous acid (HOBr), hydrogen bromide (HBr), perhydroxyl radical (HO2) and nitrous oxide (N2O) the emission lines producing the largest change in brightness temperature are identified and minimum integration times and maximum receiver noise temperatures estimated. The optimal lines for all species are shown to vary significantly between location and scenario, strengthening the case for future hyperspectral instruments that measure over a broad frequency range. We also demonstrate the feasibility of measuring horizontal wind profiles above Halley station, Antarctica with time resolution as high as 0.5hr using simulated spectroradiometric observations of Doppler-shifted ozone (O3) and carbon monoxide (CO) lines in the 230-250 GHz region. The techniques presented provide a framework that can be applied to the retrieval of additional atmospheric parameters and be taken forward to simulate and guide the design of future microwave and sub

  16. On the unsteady motion and stability of a heaving airfoil in ground effect

    Institute of Scientific and Technical Information of China (English)

    Juan Molina; Xin Zhang; David Angland

    2011-01-01

    This study explores the fluid mechanics and force generation capabilities of an inverted heaving airfoil placed close to a moving ground using a URANS solver with the Spalart-Allmaras turbulence model. By varying the mean ground clearance and motion frequency of the airfoil, it was possible to construct a frequency-height diagram of the various forces acting on the airfoil. The ground was found to enhance the downforce and reduce the drag with respect to freestream. The unsteady motion induces hysteresis in the forces' behaviour. At moderate ground clearance, the hysteresis increases with frequency and the airfoil loses energy to the flow, resulting in a stabilizing motion. By analogy with a pitching motion, the airfoil stalls in close proximity to the ground. At low frequencies, the motion is unstable and could lead to stall flutter. A stall flutter analysis was undertaken. At higher frequencies, inviscid effects overcome the large separation and the motion becomes stable. Forced trailing edge vortex shedding appears at high frequencies. The shedding mechanism seems to be independent of ground proximity.However, the wake is altered at low heights as a result of an interaction between the vortices and the ground.

  17. An Earthquake Source Ontology for Seismic Hazard Analysis and Ground Motion Simulation

    Science.gov (United States)

    Zechar, J. D.; Jordan, T. H.; Gil, Y.; Ratnakar, V.

    2005-12-01

    Representation of the earthquake source is an important element in seismic hazard analysis and earthquake simulations. Source models span a range of conceptual complexity - from simple time-independent point sources to extended fault slip distributions. Further computational complexity arises because the seismological community has established so many source description formats and variations thereof; what this means is that conceptually equivalent source models are often expressed in different ways. Despite the resultant practical difficulties, there exists a rich semantic vocabulary for working with earthquake sources. For these reasons, we feel it is appropriate to create a semantic model of earthquake sources using an ontology, a computer science tool from the field of knowledge representation. Unlike the domain of most ontology work to date, earthquake sources can be described by a very precise mathematical framework. Another uniqueness associated with developing such an ontology is that earthquake sources are often used as computational objects. A seismologist generally wants more than to simply construct a source and have it be well-formed and properly described; additionally, the source will be used for performing calculations. Representation and manipulation of complex mathematical objects presents a challenge to the ontology development community. In order to enable simulations involving many different types of source models, we have completed preliminary development of a seismic point source ontology. The use of an ontology to represent knowledge provides machine interpretability and the ability to validate logical consistency and completeness. Our ontology, encoded using the OWL Web Ontology Language - a standard from the World Wide Web Consortium, contains the conceptual definitions and relationships necessary for source translation services. For example, specification of strike, dip, rake, and seismic moment will automatically translate into a double

  18. A high performance computing framework for physics-based modeling and simulation of military ground vehicles

    Science.gov (United States)

    Negrut, Dan; Lamb, David; Gorsich, David

    2011-06-01

    This paper describes a software infrastructure made up of tools and libraries designed to assist developers in implementing computational dynamics applications running on heterogeneous and distributed computing environments. Together, these tools and libraries compose a so called Heterogeneous Computing Template (HCT). The heterogeneous and distributed computing hardware infrastructure is assumed herein to be made up of a combination of CPUs and Graphics Processing Units (GPUs). The computational dynamics applications targeted to execute on such a hardware topology include many-body dynamics, smoothed-particle hydrodynamics (SPH) fluid simulation, and fluid-solid interaction analysis. The underlying theme of the solution approach embraced by HCT is that of partitioning the domain of interest into a number of subdomains that are each managed by a separate core/accelerator (CPU/GPU) pair. Five components at the core of HCT enable the envisioned distributed computing approach to large-scale dynamical system simulation: (a) the ability to partition the problem according to the one-to-one mapping; i.e., spatial subdivision, discussed above (pre-processing); (b) a protocol for passing data between any two co-processors; (c) algorithms for element proximity computation; and (d) the ability to carry out post-processing in a distributed fashion. In this contribution the components (a) and (b) of the HCT are demonstrated via the example of the Discrete Element Method (DEM) for rigid body dynamics with friction and contact. The collision detection task required in frictional-contact dynamics (task (c) above), is shown to benefit on the GPU of a two order of magnitude gain in efficiency when compared to traditional sequential implementations. Note: Reference herein to any specific commercial products, process, or service by trade name, trademark, manufacturer, or otherwise, does not imply its endorsement, recommendation, or favoring by the United States Army. The views and

  19. Airport Ground Services Scheduling Simulation and Optimization%机场地面作业仿真与优化

    Institute of Scientific and Technical Information of China (English)

    黄鹂诗; 杨文东

    2014-01-01

    In view of airport ground services scheduling, which is a mixed process optimization of fixed site and job-shop, a model is built which employs the object-oriented simulation software SIMIO to simulate the all-day operation of the shuttle bus and fuel truck. This article proposes a two-objective optimi-zation aiming at minimizing flight delays and reducing equipment wastage. And then it analyzes the results of vehicle assignment plan to find out the existing problems. Through changing the logic condition of the system, an optimization solution has been put forward to improve equipment utilization.%针对机场地面作业调度这一定位型流程(Fixed Site)和JOBSHOP二者混合的流程优化问题,运用面向对象的SIMIO仿真软件实现机坪保障设备中摆渡车、加油车的全天运行。提出基于平衡设备工作量差和航班延误最少的双优化目标,对仿真所得的车辆指派计划进行统计分析,找出存在的问题,通过更改系统逻辑条件建立优化模型,根据优化目标给出最终优化方案。

  20. Force Limiting Vibration Tests Evaluated from both Ground Acoustic Tests and FEM Simulations of a Flight Like Vehicle System Assembly

    Science.gov (United States)

    Smith, Andrew; LaVerde, Bruce; Waldon, James; Hunt, Ron

    2014-01-01

    Marshall Space Flight Center has conducted a series of ground acoustic tests with the dual goals of informing analytical judgment, and validating analytical methods when estimating vibroacoustic responses of launch vehicle subsystems. The process of repeatedly correlating finite element-simulated responses with test-measured responses has assisted in the development of best practices for modeling and post-processing. In recent work, force transducers were integrated to measure interface forces at the base of avionics box equipment. Other force data was indirectly measured using strain gauges. The combination of these direct and indirect force measurements has been used to support and illustrate the advantages of implementing the Force Limiting approach for equipment qualification tests. The comparison of force response from integrated system level tests to measurements at the same locations during component level vibration tests provides an excellent illustration. A second comparison of the measured response cases from the system level acoustic tests to finite element simulations has also produced some principles for assessing the suitability of Finite Element Models (FEMs) for making vibroacoustics estimates. The results indicate that when FEM models are employed to guide force limiting choices, they should include sufficient detail to represent the apparent mass of the system in the frequency range of interest.

  1. Soft Soil Site Characterization on the Coast of Yantai and Its Effect on Ground Motion Parameters

    Institute of Scientific and Technical Information of China (English)

    Lü Yuejun; Tang Rongyu; Peng Yanju

    2005-01-01

    According to the Chinese GB50011-2001 code and the recommended provisions of FEMANEHRP and EUROCODE 8, by using shear wave velocity and borehole data, the site classification is evaluated for a typical soft soil site on the Yantai seacoast. The site seismic ground motion effect is analyzed and the influence of the coastal soil on design ground motion parameters is discussed. The results show that the brief site classification can not represent the real conditions of a soft soil site; the soft soil on the coast has a remarkable impact on the magnitude and spectrum of ground motion acceleration. The magnification on peak acceleration is bigger, however, due to the nonlinear deformation of the soil. The magnification is reduced nonlinearly with the increase of input ground motion; the spectrum is broadened and the characteristic period elongated on the soft soil site.

  2. Simulated ground-water flow and water quality of the Mississippi River alluvium near Burlington, Iowa, 1999

    Science.gov (United States)

    Boyd, Robert A.

    2001-01-01

    The City of Burlington, Iowa, obtains some of its public water supply by withdrawing ground water from the Mississippi River alluvium, an alluvial aquifer adjacent to the Mississippi River. The U.S. Geological Survey, in cooperation with the City of Burlington, conducted a hydrologic study of the Mississippi River alluvium near Burlington in 1999 to improve understanding of the flow system, evaluate the effects of hypothetical pumping scenarios on the flow system, and evaluate selected water-quality constituents in parts of the alluvium.

  3. Effects of aging on figure-ground perception: Convexity context effects and competition resolution.

    Science.gov (United States)

    Lass, Jordan W; Bennett, Patrick J; Peterson, Mary A; Sekuler, Allison B

    2017-02-01

    We examined age-related differences in figure-ground perception by exploring the effect of age on Convexity Context Effects (CCE; Peterson & Salvagio, 2008). Experiment 1, using Peterson and Salvagio's procedure and black and white stimuli consisting of 2 to 8 alternating concave and convex regions, established that older adults exhibited reduced CCEs compared to younger adults. Experiments 2 and 3 demonstrated that this age difference was found at various stimulus durations and sizes. Experiment 4 compared CCEs obtained with achromatic stimuli, in which the alternating convex and concave regions were each all black or all white, and chromatic stimuli in which the concave regions were homogeneous in color but the convex regions varied in color. We found that the difference between CCEs measured with achromatic and colored stimuli was larger in older than in younger adults. Our results are consistent with the hypothesis that the senescent visual system is less able to resolve the competition among various perceptual interpretations of the figure-ground relations among stimulus regions.

  4. Study on the effect of ground motion direction on the response of engineering structure

    Science.gov (United States)

    Sun, Menghan; Fan, Feng; Sun, Baitao; Zhi, Xudong

    2016-12-01

    Due to the randomness of earthquake wave magnitude and direction, and the uncertain direction of strong axis and weak axis in the construction of engineering structures, the effect of the direction of ground motion on a structure are studied herein. Ground motion records usually contain three vertical ground motion data, which are obtained by sensors arranged in accordance with the EW (East -West) direction, NS (South- North) direction and perpendicular to the surface ( z) direction, referring to the construction standard of seismic stations. The seismic records in the EW and NS directions are converted to Cartesian coordinates in accordance with the rotation of θ = 0°-180°, and consequently, a countless group of new ground motion time histories are obtained. Then, the characteristics of the ground motion time history and response spectrum of each group were studied, resulting in the following observations: (1) the peak and phase of ground motion are changed with the rotation of direction θ, so that the direction θ of the maximum peak ground motion can be determined; (2) response spectrum values of each group of ground motions change along with the direction θ, and their peak, predominant period and declining curve are also different as the changes occur; then, the angle θ in the direction of the maximum peak value or the widest predominant period can be determined; and (3) the seismic response of structures with different directions of ground motion inputs has been analyzed under the same earthquake record, and the results show the difference. For some ground motion records, such as the Taft seismic wave, these differences are significant. Next, the Lushan middle school gymnasium structure was analyzed and the calculation was checked using the proposed method, where the internal force of the upper space truss varied from 25% to 28%. The research results presented herein can be used for reference in choosing the ground motion when checking the actual damage

  5. Marijuana effects on simulated flying ability.

    Science.gov (United States)

    Janowsky, D S; Meacham, M P; Blaine, J D; Schoor, M; Bozzetti, L P

    1976-04-01

    The authors studied the effects of marijuana intoxication on the ability of 10 certified airplane pilots to operate a flight simulator. They used a randomized double-blind crossover design to compare the effect of active versus placebo marijuana. They found that all 10 pilots showed a significant decrease in measurements of flying performance 30 minutes after smoking active marijuana. For a group of 6 pilots tested sequentially for 6 hours, a nonsignificant decrease in flying performance continued for 2 hours after smoking the active drug. The authors conclude that the effects of marijuana on flying performance may represent a sensitive indicator of the drug's psychomotor effects.

  6. Simulation of aerosol optical properties over a tropical urban site in India using a global model and its comparison with ground measurements

    Directory of Open Access Journals (Sweden)

    T. Takemura

    2011-05-01

    Full Text Available Aerosols have great impacts on atmospheric environment, human health, and earth's climate. Therefore, information on their spatial and temporal distribution is of paramount importance. Despite numerous studies have examined the variation and trends of BC and AOD over India, only very few have focused on their spatial distribution or even correlating the observations with model simulations. In the present study, a three-dimensional aerosol transport-radiation model coupled with a general circulation model. SPRINTARS, simulated atmospheric aerosol distributions including BC and aerosol optical properties, i.e., aerosol optical thickness (AOT, Ångström Exponent (AE, and single scattering albedo (SSA. The simulated results are compared with both BC measurements by aethalometer and aerosol optical properties measured by ground-based skyradiometer and by satellite sensor, MODIS/Terra over Hyderabad, which is a tropical urban area of India, for the year 2008. The simulated AOT and AE in Hyderabad are found to be comparable to ground-based measured ones. The simulated SSA tends to be higher than the ground-based measurements. Both these comparisons of aerosol optical properties between the simulations with different emission inventories and the measurements indicate that, firstly the model uncertainties derived from aerosol emission inventory cannot explain the gaps between the simulations and the measurements and secondly the vertical transport of BC and the treatment of BC-containing particles can be the main issue in the global model to solve the gap.

  7. Quadrifilar Helix Antenna for Enhanced Air-to-Ground Communications

    Science.gov (United States)

    2016-05-01

    5d. PROJECT NUMBER TPA # CE-SE-2014-09 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) US Army...effect of the metallic ground plane provided by the aircraft fuselage is explored through simulation, and the ideal standoff distance from this ground...Fig. 5 Effect of ground plane and absorber on QHA reflection coefficient .....4 Fig. 6 Effect of ground plane and absorber on QHA radiation pattern

  8. Simulation of Regional Ground-Water Flow in the Suwannee River Basin, Northern Florida and Southern Georgia

    Science.gov (United States)

    Planert, Michael

    2007-01-01

    -lying surficial and underlying Upper Floridan aquifers. The Upper Floridan aquifer is present throughout the study area and is extremely permeable and typically capable of transmitting large volumes of water. This high permeability largely is due to the widening of fractures and formation of conduits within the aquifer through dissolu-tion of the limestone by infiltrating water. This process has also produced numerous karst features such as springs, sinking streams, and sinkholes. A model of the Upper Floridan aquifer was created to better understand the ground-water system and to provide resource managers a tool to evaluate ground-water and surface-water interactions in the Suwannee River Basin. The model was developed to simulate a single Upper Floridan aquifer layer. Recharge datasets were developed to represent a net flux of water to the top of the aquifer or the water table during a period when the system was assumed to be under steady-state conditions (September 1990). A potentiometric-surface map representing water levels during September 1990 was prepared for the Suwannee River Water Management District (SRWMD), and the heads from those wells were used for calibration of the model. Additionally, flows at gaging sites for the Suwannee, Alapaha, Withlacoochee, Santa Fe, Fenholloway, Aucilla, Ecofina, and Steinhatchee Rivers were used during the calibration process to compare to model computed flows. Flows at seven first-magnitude springs selected by the SRWMD also were used to calibrate the model. Calibration criterion for matching potentiometric heads was to attain an absolute residual mean error of 5 percent or less of the head gradient of the system which would be about 5 feet. An absolute residual mean error of 4.79 feet was attained for final calibration. Calibration criterion for matching streamflow was based on the quality of measurements made in the field. All measurements used were rated ?good,? so the desire was for simulated values to be wi

  9. "Negotiating, navigating, and networking": three strategies used by nursing leaders to shape the adoption and incorporation of simulation into nursing curricula-a grounded theory study.

    Science.gov (United States)

    Taplay, Karyn; Jack, Susan M; Baxter, Pamela; Eva, Kevin; Martin, Lynn

    2014-01-01

    Background. Implementing simulation requires a substantial commitment of human and financial resources. Despite this, little is known about the strategies used by academic nursing leaders to facilitate the implementation of a simulation program in nursing curricula. Methods. A constructivist grounded theory study was conducted within 13 nursing programs in Ontario, Canada. Perspectives of key stakeholders (n = 27) including nursing administrators (n = 6), simulation leaders (n = 9), and nursing faculty (n = 12) were analyzed using the constant comparison method. Results. Nursing leaders, specifically nursing administrators and simulation leaders who successfully led the adoption and incorporation of simulation into nursing curricula, worked together and utilized negotiating, navigating, and networking strategies that impacted the adoption and incorporation of simulation into nursing curricula. Conclusions. Strategies that were found to be useful when planning and executing the adoption and incorporation of an innovation, specifically simulation, into nursing curricula provide practical approaches that may be helpful to nurse leaders when embarking upon an organizational change.

  10. A three-dimensional full Stokes model of the grounding line dynamics: effect of a pinning point beneath the ice shelf

    Directory of Open Access Journals (Sweden)

    L. Favier

    2012-01-01

    Full Text Available The West Antarctic ice sheet is confined by a large area of ice shelves, fed by inland ice through fast flowing ice streams. The dynamics of the grounding line, which is the line-boundary between grounded ice and the downstream ice shelf, has a major influence on the dynamics of the whole ice sheet. However, most ice sheet models use simplifications of the flow equations, as they do not include all the stress components, and are known to fail in their representation of the grounding line dynamics. Here, we present a 3-D full Stokes model of a marine ice sheet, in which the flow problem is coupled with the evolution of the upper and lower free surfaces, and the position of the grounding line is determined by solving a contact problem between the shelf/sheet lower surface and the bedrock. Simulations are performed using the open-source finite-element code Elmer/Ice within a parallel environment. The model's ability to cope with a curved grounding line and the effect of a pinning point beneath the ice shelf are investigated through prognostic simulations. Starting from a steady state, the sea level is slightly decreased to create a contact point between a seamount and the ice shelf. The model predicts a dramatic decrease of the shelf velocities, leading to an advance of the grounding line until both grounded zones merge together, during which an ice rumple forms above the contact area at the pinning point. Finally, we show that once the contact is created, increasing the sea level to its initial value does not release the pinning point and has no effect on the ice dynamics, indicating a stabilising effect of pinning points.

  11. Bonding effectiveness of different adhesion approaches to unground versus ground primary tooth enamel.

    Science.gov (United States)

    Knirsch, M S; Bonifácio, C C; Shimaoka, A M; Andrade, A P; Carvalho, R C R

    2009-06-01

    This study aims to evaluate the bonding effectiveness of self-etch and etch-and-rinse adhesive systems in on intact and ground primary tooth enamel. Sixty primary incisors were divided into 6 groups according to the adhesive system (etch-and-rinse - Adper Single Bond 2 - SB, 2 steps self-etch -Clearfil SE Bond - SE, and 1 step self-etch - One Up Bond F Plus OBF) and to the substrate (ground or intact enamel): G1-SB/intact enamel; G2-SE/intact enamel; G3- OBF/intact enamel; G4-SB/ground enamel; G5- SE/ground enamel and G6-OBF/ground enamel. Microshear bond test specimens were prepared with microhybrid composite and after 24h of water storage the microshear test was performed. Data were submitted to statistical analysis using two-way ANOVA and Tukey's tests (penamel characteristics (ground or intact) only when SE was used a statistically significant difference was found, as G2 (21.12+/-4.52) was statistically lower than G5 (33.29+/-5.44). Among the intact enamel groups, SB (26.11+/-7.56) was statistically superior to SE (21.12+/-4.52) and OBF (17.01+/-3.96). However, when comparisons were made among groups of ground enamel, SE (33.29+/-5.44) was significantly higher than SB (26.35+/-8.18) and OBF (17.52+/-3.46). The two-step self-etch adhesive system is a reliable alternative to etch and rinse adhesive systems on both ground and intact primary enamel.

  12. Ground motion in the presence of complex Topography II: Earthquake sources and 3D simulations

    Science.gov (United States)

    Hartzell, Stephen; Ramirez-Guzman, Leonardo; Meremonte, Mark; Leeds, Alena L.

    2017-01-01

    Eight seismic stations were placed in a linear array with a topographic relief of 222 m over Mission Peak in the east San Francisco Bay region for a period of one year to study topographic effects. Seventy‐two well‐recorded local earthquakes are used to calculate spectral amplitude ratios relative to a reference site. A well‐defined fundamental resonance peak is observed with individual station amplitudes following the theoretically predicted progression of larger amplitudes in the upslope direction. Favored directions of vibration are also seen that are related to the trapping of shear waves within the primary ridge dimensions. Spectral peaks above the fundamental one are also related to topographic effects but follow a more complex pattern. Theoretical predictions using a 3D velocity model and accurate topography reproduce many of the general frequency and time‐domain features of the data. Shifts in spectral frequencies and amplitude differences, however, are related to deficiencies of the model and point out the importance of contributing factors, including the shear‐wave velocity under the topographic feature, near‐surface velocity gradients, and source parameters.

  13. Ground effect on the aerodynamics of a two-dimensional oscillating airfoil

    Science.gov (United States)

    Lu, H.; Lua, K. B.; Lim, T. T.; Yeo, K. S.

    2014-07-01

    This paper reports results of an experimental investigation into ground effect on the aerodynamics of a two-dimensional elliptic airfoil undergoing simple harmonic translation and rotational motion. Ground clearance ( D) ranging from 1 c to 5 c (where c is the airfoil chord length) was investigated for three rotational amplitudes ( α m) of 30°, 45° and 60° (which respectively translate to mid-stroke angle of attack of 60°, 45° and 30°). For the lowest rotational amplitude of 30°, results show that an airfoil approaching a ground plane experiences a gradual decrease in cycle-averaged lift and drag coefficients until it reaches D ≈ 2.0 c, below which they increase rapidly. Corresponding DPIV measurement indicates that the initial force reduction is associated with the formation of a weaker leading edge vortex and the subsequent force increase below D ≈ 2.0 c may be attributed to stronger wake capture effect. Furthermore, an airfoil oscillating at higher amplitude lessens the initial force reduction when approaching the ground and this subsequently leads to lift distribution that bears striking resemblance to the ground effect on a conventional fixed wing in steady translation.

  14. Effects of ascorbic acid and antioxidants on color, lipid oxidation and volatiles of irradiated ground beef

    Science.gov (United States)

    Ahn, D. U.; Nam, K. C.

    2004-09-01

    Beef loins with 3 different aging times after slaughter were ground, added with none, 0.1% ascorbic acid, 0.01% sesamol+0.01% α-tocopherol, or 0.1% ascorbic acid+0.01% sesamol+0.01% tocopherol. The meats were packaged in oxygen-permeable bags, irradiated at 2.5 kGy, and color, oxidation-reduction potential (ORP), lipid oxidation and volatile profiles were determined. Irradiation decreased the redness of ground beef, and visible color of beef changed from a bright red to a green/brown depending on the age of meat. Addition of ascorbic acid prevented color changes in irradiated beef, and the effect of ascorbic acid became greater as the age of meat or storage time after irradiation increased. The ground beef added with ascorbic acid had lower ORP than control, and the low ORP of meat helped maintaining the heme pigments in reduced form. During aerobic storage, S-volatiles disappeared while volatile aldehydes significantly increased in irradiated beef. Addition of ascorbic acid at 0.1% or sesamol+α-tocopherol at each 0.01% level to ground beef prior to irradiation were effective in reducing lipid oxidation and S-volatiles. As storage time increased, however, the antioxidant effect of sesamol+tocopherol in irradiated ground beef was superior to that of ascorbic acid.

  15. Effects of ascorbic acid and antioxidants on color, lipid oxidation and volatiles of irradiated ground beef

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, D.U. E-mail: duahn@iastate.edu; Nam, K.C

    2004-10-01

    Beef loins with 3 different aging times after slaughter were ground, added with none, 0.1% ascorbic acid, 0.01% sesamol+0.01% {alpha}-tocopherol, or 0.1% ascorbic acid+0.01% sesamol+0.01% tocopherol. The meats were packaged in oxygen-permeable bags, irradiated at 2.5 kGy, and color, oxidation-reduction potential (ORP), lipid oxidation and volatile profiles were determined. Irradiation decreased the redness of ground beef, and visible color of beef changed from a bright red to a green/brown depending on the age of meat. Addition of ascorbic acid prevented color changes in irradiated beef, and the effect of ascorbic acid became greater as the age of meat or storage time after irradiation increased. The ground beef added with ascorbic acid had lower ORP than control, and the low ORP of meat helped maintaining the heme pigments in reduced form. During aerobic storage, S-volatiles disappeared while volatile aldehydes significantly increased in irradiated beef. Addition of ascorbic acid at 0.1% or sesamol+{alpha}-tocopherol at each 0.01% level to ground beef prior to irradiation were effective in reducing lipid oxidation and S-volatiles. As storage time increased, however, the antioxidant effect of sesamol+tocopherol in irradiated ground beef was superior to that of ascorbic acid.

  16. Pre-Shot Simulations of Far-Field Ground Motions for the Source Physics Experiment (SPE) Explosions at the Climax Stock, Nevada National Security Site

    Energy Technology Data Exchange (ETDEWEB)

    Rodgers, A J; Wagoner, J; Petersson, N A; Sjogreen, B

    2010-11-07

    The Source Physics Experiment (SPE) will involve a series of explosions in various geologic and emplacement conditions to validate numerical simulation methods to predict behavior of seismic wave excitation and propagation for nuclear test monitoring. The first SPE's currently underway involve explosions in the Climax Stock (granitic geology) at the Nevada National Security Site (NNSS). Detailed geologic data and published material properties for the major lithologic units of the NNSS and surrounding region were used to build three-dimensional models for seismic wave propagation simulations. The geologic structure near the SPE shot point is quite varied including granitic, carbonate, tuff and alluvium lithologies. We performed preliminary ground motion simulations for a near-source domain covering 8 km x 8 km at the surface centered on the shot point to investigate various source and propagation effects using WPP, LLNL's anelastic seismic wave finite difference code. Simulations indicate that variations in wave propagation properties of the sub-surface will generate strongly path-dependent response once the energy has left the relatively small granitic geology of the near-surface Climax Stock near the SPE shot point. Rough topography to the north and west of SPE shot point causes additional complexity in the signals including energy on the transverse components. Waves propagate much faster through the granitic and carbonate formations and slower through the tuff and alluvium. Synthetic seismograms for a pure explosion source in a 3D geologic structure show large amplitudes on transverse component. For paths to the south sampling the granite, tuff and alluvium lithologies transverse component amplitudes are as high as 50% of that on the vertical and radial components.

  17. Lessons Learned from Biosphere 2: When Viewed as a Ground Simulation/Analogue for Long Duration Human Space Exploration and Settlement

    Science.gov (United States)

    MacCallum, T.; Poynter, J.; Bearden, D.

    A human mission to Mars, or a base on the Moon or Mars, is a longer and more complex mission than any space endeavor undertaken to date. Ground simulations provide a relevant, analogous environment for testing technologies and learning how to manage complex, long duration missions, while addressing inherent mission risks. Multiphase human missions and settlements that may preclude a rapid return to Earth, require high fidelity, end-to-end, at least full mission duration tests in order to evaluate a system's ability to sustain the crew for the entire mission and return the crew safely to Earth. Moreover, abort scenarios are essentially precluded in many mission scenarios, though certain risks may only become evident late in the mission. Aging and compounding effects cannot be simulated through accelerated tests for all aspects of the mission. Until such high fidelity long duration simulations are available, and in order to help prepare those simulations and mission designs, it is important to extract as many lessons as possible from analogous environments. Possibly the best analogue for a long duration space mission is the two year mission of Biosphere 2. Biosphere 2 is a three-acre materially closed ecological system that supported eight crewmembers with food, air and water in a sunlight driven bioregenerative system for two years. It was designed for research applicable to environmental management on Earth and the development of human life support for space. A brief overview of the two-year Biosphere 2 mission is presented, followed by select data and lessons learned that are applicable to the design and operation of a long duration human space mission, settlement or test bed. These lessons include technical, programmatic, and psychological issues

  18. Longitudinal static stability requirements for wing in ground effect vehicle

    Science.gov (United States)

    Yang, Wei; Yang, Zhigang; Collu, Maurizio

    2015-06-01

    The issue of the longitudinal stability of a WIG vehicle has been a very critical design factor since the first experimental WIG vehicle has been built. A series of studies had been performed and focused on the longitudinal stability analysis. However, most studies focused on the longitudinal stability of WIG vehicle in cruise phase, and less is available on the longitudinal static stability requirement of WIG vehicle when hydrodynamics are considered: WIG vehicle usually take off from water. The present work focuses on stability requirement for longitudinal motion from taking off to landing. The model of dynamics for a WIG vehicle was developed taking into account the aerodynamic, hydrostatic and hydrodynamic forces, and then was analyzed. Following with the longitudinal static stability analysis, effect of hydrofoil was discussed. Locations of CG, aerodynamic center in pitch, aerodynamic center in height and hydrodynamic center in heave were illustrated for a stabilized WIG vehicle. The present work will further improve the longitudinal static stability theory for WIG vehicle.

  19. Longitudinal static stability requirements for wing in ground effect vehicle

    Directory of Open Access Journals (Sweden)

    Wei Yang

    2015-03-01

    Full Text Available The issue of the longitudinal stability of a WIG vehicle has been a very critical design factor since the first experimental WIG vehicle has been built. A series of studies had been performed and focused on the longitudinal stability analysis. However, most studies focused on the longitudinal stability of WIG vehicle in cruise phase, and less is available on the longitudinal static stability requirement of WIG vehicle when hydrodynamics are considered: WIG vehicle usually take off from water. The present work focuses on stability requirement for longitudinal motion from taking off to landing. The model of dynamics for a WIG vehicle was developed taking into account the aerodynamic, hydrostatic and hydrodynamic forces, and then was analyzed. Following with the longitudinal static stability analysis, effect of hydrofoil was discussed. Locations of CG, aerodynamic center in pitch, aerodynamic center in height and hydrodynamic center in heave were illustrated for a stabilized WIG vehicle. The present work will further improve the longitudinal static stability theory for WIG vehicle.

  20. Longitudinal static stability requirements for wing in ground effect vehicle

    Directory of Open Access Journals (Sweden)

    Yang Wei

    2015-06-01

    Full Text Available The issue of the longitudinal stability of a WIG vehicle has been a very critical design factor since the first experimental WIG vehicle has been built. A series of studies had been performed and focused on the longitudinal stability analysis. However, most studies focused on the longitudinal stability of WIG vehicle in cruise phase, and less is available on the longitudinal static stability requirement of WIG vehicle when hydrodynamics are considered: WIG vehicle usually take off from water. The present work focuses on stability requirement for longitudinal motion from taking off to landing. The model of dynamics for a WIG vehicle was developed taking into account the aerodynamic, hydrostatic and hydrodynamic forces, and then was analyzed. Following with the longitudinal static stability analysis, effect of hydrofoil was discussed. Locations of CG, aerodynamic center in pitch, aerodynamic center in height and hydrodynamic center in heave were illustrated for a stabilized WIG vehicle. The present work will further improve the longitudinal static stability theory for WIG vehicle.

  1. A Digital Ground Distance Relaying Algorithm to Reduce the Effect of Fault Resistance during Single Phase to Ground and Simultaneous Faults

    Directory of Open Access Journals (Sweden)

    Mohammad Razaz

    2015-03-01

    Full Text Available This paper provides an algorithm of fault resistance compensation for digital ground distance relay considering the voltage and current transformer effects. Performance of the conventional ground distance relaying manner is adversely affected by different ground faults and also typical type, called a simultaneous open conductor and ground fault. The proposed scheme by using local-end data only, has shown satisfactory performances under wide variations in fault location, with different values of fault resistance and having positive and negative of power transfer angle. The presented method which has been carried out on the IEEE 14 bus benchmark is executed in PSCAD/EMTDC and MATLAB software, and the results show the accurate performance of mentioned configuration.

  2. Science Results from a Mars Drilling Simulation (Río Tinto, Spain) and Ground Truth for Remote Science Observations

    Science.gov (United States)

    Bonaccorsi, Rosalba; Stoker, Carol R.

    2008-10-01

    Science results from a field-simulated lander payload and post-mission laboratory investigations provided "ground truth" to interpret remote science observations made as part of the 2005 Mars Astrobiology Research and Technology Experiment (MARTE) drilling mission simulation. The experiment was successful in detecting evidence for life, habitability, and preservation potential of organics in a relevant astrobiological analogue of Mars. Science results. Borehole 7 was drilled near the Río Tinto headwaters at Peña de Hierro (Spain) in the upper oxidized remnant of an acid rock drainage system. Analysis of 29 cores (215 cm of core was recovered from 606 cm penetrated depth) revealed a matrix of goethite- (42-94%) and hematite-rich (47-87%) rocks with pockets of phyllosilicates (47-74%) and fine- to coarse-grained loose material. Post-mission X-ray diffraction (XRD) analysis confirmed the range of hematite:goethite mixtures that were visually recognizable (˜1:1, ˜1:2, and ˜1:3 mixtures displayed a yellowish-red color whereas 3:1 mixtures displayed a dark reddish-brown color). Organic carbon was poorly preserved in hematite/goethite-rich materials (Corg <0.05 wt %) beneath the biologically active organic-rich soil horizon (Corg ˜3-11 wt %) in contrast to the phyllosilicate-rich zones (Corg ˜0.23 wt %). Ground truth vs. remote science analysis. Laboratory-based analytical results were compared to the analyses obtained by a Remote Science Team (RST) using a blind protocol. Ferric iron phases, lithostratigraphy, and inferred geologic history were correctly identified by the RST with the exception of phyllosilicate-rich materials that were misinterpreted as weathered igneous rock. Adenosine 5‧-triphosphate (ATP) luminometry, a tool available to the RST, revealed ATP amounts above background noise, i.e., 278-876 Relative Luminosity Units (RLUs) in only 6 cores, whereas organic carbon was detected in all cores. Our manned vs. remote observations based on automated

  3. Effective Use of Simulation Means in Collective Mission Simulation

    NARCIS (Netherlands)

    Voogd, J.M.; Lemmers, A.; Gerretsen, A.; Roza, M.; Karelse, R.

    2009-01-01

    Mission training and rehearsal are vital to successful operations. Advances in modeling and simulation (M&S) technology now allow for Collective Mission Simulation (CMS). The Royal Netherlands Armed Forces have exploited CMS through participation in a number of virtual exercises. The potential of co

  4. A comparative study of a stochastic and deterministic simulation of strong ground motion applied to the Kozani-Grevena (NW Greece 1995 sequence

    Directory of Open Access Journals (Sweden)

    C. Papaioannou

    2000-06-01

    Full Text Available We present the results of a comparative study of two intrinsically different methodologies, a stochastic one and a deterministic one, performed to simulate strong ground motion in the Kozani area (NW Greece. Source parameters were calculated from empirical relations in order to check their reliability, in combination with the applied methodologies, to simulate future events. Strong ground motion from the Kozani mainshock (13 May, 1995, M w = 6.5 was synthesized by using both the stochastic method for finite-fault cases and the empirical Green’s function method. The latter method was also applied to simulate a Mw = 5.1 aftershock (19 May, 1995. The results of the two simulations computed for the mainshock are quite satisfactory for both methodologies at the frequencies of engineering interest (> ~ 2 Hz. This strengthens the idea of incorporating proper empirical relations for the estimation of source parameters in a priori simulations of strong ground motion from future earthquakes. Nevertheless, the results of the simulation of the smaller earthquake point out the need for further investigation of regional or local, if possible, relations for estimating source parameters at smaller magnitude ranges

  5. Effect of Ground Motion Directionality on Fragility Characteristics of a Highway Bridge

    Directory of Open Access Journals (Sweden)

    Swagata Banerjee Basu

    2011-01-01

    Full Text Available It is difficult to incorporate multidimensional effect of the ground motion in the design and response analysis of structures. The motion trajectory in the corresponding multi-dimensional space results in time variant principal axes of the motion and defies any meaningful definition of directionality of the motion. However, it is desirable to consider the directionality of the ground motion in assessing the seismic damageability of bridges which are one of the most vulnerable components of highway transportation systems. This paper presents a practice-oriented procedure in which the structure can be designed to ensure the safety under single or a pair of independent orthogonal ground motions traveling horizontally with an arbitrary direction to structural axis. This procedure uses nonlinear time history analysis and accounts for the effect of directionality in the form of fragility curves. The word directionality used here is different from “directivity” used in seismology to mean a specific characteristic of seismic fault movement.

  6. Validating Virtual Safety Stock Effectiveness through Simulation

    Directory of Open Access Journals (Sweden)

    Maria Elena Nenni

    2013-08-01

    safety stock effectiveness through simulation in an inventory system using a base stock policy with periodic reviews and backorders. This approach can be useful for researchers as well as practitioners who want to model the behaviour of an inventory system under uncertain conditions and verify the opportunity for setting up a virtual safety stock on top of, or instead of, the traditional physical safety stock.

  7. Simulation and optimisation of a ground source heat pump with different ground heat exchanger configurations for a single-family residential house

    DEFF Research Database (Denmark)

    Pavlov, Georgi Krasimiroy; Olesen, Bjarne W.

    2012-01-01

    In the future there will be an increased demand for energy efficient cooling of residential buildings. Therefore it is essential to develop cooling concepts that are passive and/or using very little primary energy. A possible solution is a ground source heat pump combined with a low....... For the studied geographical location, passive cooling by bypassing the heat pump and using only the ground heat exchanger can provide acceptable room temperatures.......-temperature heating and high-temperature cooling system. The present work evaluates the performance in relation to thermal comfort and energy consumption of a GSHP with different GHE concepts. The different configurations are analyzed being part of the energy supply system of a low-energy residential house...

  8. Simulations of Ground-Water Flow and Particle Pathline Analysis in the Zone of Contribution of a Public-Supply Well in Modesto, Eastern San Joaquin Valley, California

    Science.gov (United States)

    Burow, Karen R.; Jurgens, Bryant C.; Kauffman, Leon J.; Phillips, Steven P.; Dalgish, Barbara A.; Shelton, Jennifer L.

    2008-01-01

    Shallow ground water in the eastern San Joaquin Valley is affected by high nitrate and uranium concentrations and frequent detections of pesticides and volatile organic compounds (VOC), as a result of ground-water development and intensive agricultural and urban land use. A single public-supply well was selected for intensive study to evaluate the dominant processes affecting the vulnerability of public-supply wells in the Modesto area. A network of 23 monitoring wells was installed, and water and sediment samples were collected within the approximate zone of contribution of the public-supply well, to support a detailed analysis of physical and chemical conditions and processes affecting the water chemistry in the well. A three-dimensional, steady-state local ground-water-flow and transport model was developed to evaluate the age of ground water reaching the well and to evaluate the vulnerability of the well to nonpoint source input of nitrate and uranium. Particle tracking was used to compute pathlines and advective travel times in the ground-water flow model. The simulated ages of particles reaching the public-supply well ranged from 9 to 30,000 years, with a median of 54 years. The age of the ground water contributed to the public-supply well increased with depth below the water table. Measured nitrate concentrations, derived primarily from agricultural fertilizer, were highest (17 milligrams per liter) in shallow ground water and decreased with depth to background concentrations of less than 2 milligrams per liter in the deepest wells. Because the movement of water is predominantly downward as a result of ground-water development, and because geochemical conditions are generally oxic, high nitrate concentrations in shallow ground water are expected to continue moving downward without significant attenuation. Simulated long-term nitrate concentrations indicate that concentrations have peaked and will decrease in the public-supply well during the next 100 years

  9. Experimental Study on Effects of Ground Roughness on Flow Characteristics of Tornado-Like Vortices

    Science.gov (United States)

    Wang, Jin; Cao, Shuyang; Pang, Weichiang; Cao, Jinxin

    2017-02-01

    The three-dimensional wind velocity and dynamic pressure for stationary tornado-like vortices that developed over ground of different roughness categories were investigated to clarify the effects of ground roughness. Measurements were performed for various roughness categories and two swirl ratios. Variations of the vertical and horizontal distributions of velocity and pressure with roughness are presented, with the results showing that the tangential, radial, and axial velocity components increase inside the vortex core near the ground under rough surface conditions. Meanwhile, clearly decreased tangential components are found outside the core radius at low elevations. The high axial velocity inside the vortex core over rough ground surface indicates that roughness produces an effect similar to a reduced swirl ratio. In addition, the pressure drop accompanying a tornado is more significant at elevations closer to the ground under rough compared with smooth surface conditions. We show that the variations of the flow characteristics with roughness are dependent on the vortex-generating mechanism, indicating the need for appropriate modelling of tornado-like vortices.

  10. The Effect of Degradation of Ground water Resources on Capital of Pistachio Growers in Kerman Province

    Directory of Open Access Journals (Sweden)

    Seyed Mostafa Mortazavi

    2014-12-01

    Full Text Available Real cost evaluation of water is necessary in agricultural products depending on obtained value by this input. In most areas of world especially in arid and semiarid areas, exist over pumping of ground water because the real value of water is much most than the costs of water supply and the lack of fit management water resources. In this study, using a sample of 110 farmers, water dealing value of over using of groundwater in Rafsanjan pistachio production area were investigated. Analysis and regression methods were used in this regard. The average determined value obtained 24 cents, for each share of water in this region which with over drafting of ground water, and decreasing quality and quantity of water has had significant relationship in the one percent significance level. Finally, for elimination or reduction of ground water degradation and its effects, this paper recommended in addition to reduction of licenses for ground water pumping. Determination of optimal economic water/land ratio in new and old pistachio producing areas is the other proposal of this research for alleviation groundwater over drafting effects. Permission for water conduction between wells and combination of fresh and saline water and also using desalination systems are methods for solving low quality of ground water.

  11. Effects of ground cover from branches of arboreal species on weed growth and maize yield

    Directory of Open Access Journals (Sweden)

    Paulo Sérgio Lima e Silva

    Full Text Available ABSTRACTCultivating maize under systems of alley cropping results in improvements to the soil, a reduction in weeds and an increase in yield. Studies using ground cover from tree shoots produce similar results. The aim of this study was to evaluate the effects on weed growth and maize yield of ground cover made up of 30 t ha-1 (fresh matter of branches from the tree species: neem (Azadirachta indica A. Juss, gliricidia [Gliricidia sepium(Jacq. Kunth ex Walp.], leucaena [Leucaena leucocephala (Lam. de Wit.] and sabiá (Mimosa caesalpiniifolia Benth.. Two treatment groups (cultivars and weed control were evaluated. The cultivars AG 1041 and AL Bandeirantes were subjected to the following treatments: no hoeing, double hoeing, and ground a cover of branches of the above species when sowing the maize. A randomised block design was used with split lots (cultivars in the lots and ten replications. The cultivars did not differ for green ear or grain yield. Double hoeing was more effective than ground cover at reducing the growth of weeds. However, both weeding and ground cover resulted in similar yields for green ears and grain, which were greater than those obtained with the unweeded maize.

  12. Science results from a Mars drilling simulation (Río Tinto, Spain) and ground truth for remote science observations.

    Science.gov (United States)

    Bonaccorsi, Rosalba; Stoker, Carol R

    2008-10-01

    Science results from a field-simulated lander payload and post-mission laboratory investigations provided "ground truth" to interpret remote science observations made as part of the 2005 Mars Astrobiology Research and Technology Experiment (MARTE) drilling mission simulation. The experiment was successful in detecting evidence for life, habitability, and preservation potential of organics in a relevant astrobiological analogue of Mars. SCIENCE RESULTS: Borehole 7 was drilled near the Río Tinto headwaters at Peña de Hierro (Spain) in the upper oxidized remnant of an acid rock drainage system. Analysis of 29 cores (215 cm of core was recovered from 606 cm penetrated depth) revealed a matrix of goethite- (42-94%) and hematite-rich (47-87%) rocks with pockets of phyllosilicates (47-74%) and fine- to coarse-grained loose material. Post-mission X-ray diffraction (XRD) analysis confirmed the range of hematite:goethite mixtures that were visually recognizable (approximately 1:1, approximately 1:2, and approximately 1:3 mixtures displayed a yellowish-red color whereas 3:1 mixtures displayed a dark reddish-brown color). Organic carbon was poorly preserved in hematite/goethite-rich materials (C(org) TRUTH VS. REMOTE SCIENCE ANALYSIS: Laboratory-based analytical results were compared to the analyses obtained by a Remote Science Team (RST) using a blind protocol. Ferric iron phases, lithostratigraphy, and inferred geologic history were correctly identified by the RST with the exception of phyllosilicate-rich materials that were misinterpreted as weathered igneous rock. Adenosine 5'-triphosphate (ATP) luminometry, a tool available to the RST, revealed ATP amounts above background noise, i.e., 278-876 Relative Luminosity Units (RLUs) in only 6 cores, whereas organic carbon was detected in all cores. Our manned vs. remote observations based on automated acquisitions during the project provide insights for the preparation of future astrobiology-driven Mars missions.

  13. Passive Microwave Soil Moisture Retrieval through Combined Radar/Radiometer Ground Based Simulator with Special Reference to Dielectric Schemes

    Science.gov (United States)

    Srivastava, Prashant K., ,, Dr.; O'Neill, Peggy, ,, Dr.

    2014-05-01

    Soil moisture is an important element for weather and climate prediction, hydrological sciences, and applications. Hence, measurements of this hydrologic variable are required to improve our understanding of hydrological processes, ecosystem functions, and the linkages between the Earth's water, energy, and carbon cycles (Srivastava et al. 2013). The retrieval of soil moisture depends not only on parameterizations in the retrieval algorithm but also on the soil dielectric mixing models used (Behari 2005). Although a number of soil dielectric mixing models have been developed, testing these models for soil moisture retrieval has still not been fully explored, especially with SMAP-like simulators. The main objective of this work focuses on testing different dielectric models for soil moisture retrieval using the Combined Radar/Radiometer (ComRAD) ground-based L-band simulator developed jointly by NASA/GSFC and George Washington University (O'Neill et al., 2006). The ComRAD system was deployed during a field experiment in 2012 in order to provide long active/passive measurements of two crops under controlled conditions during an entire growing season. L-band passive data were acquired at a look angle of 40 degree from nadir at both horizontal & vertical polarization. Currently, there are many dielectric models available for soil moisture retrieval; however, four dielectric models (Mironov, Dobson, Wang & Schmugge and Hallikainen) were tested here and found to be promising for soil moisture retrieval (some with higher performances). All the above-mentioned dielectric models were integrated with Single Channel Algorithms using H (SCA-H) and V (SCA-V) polarizations for the soil moisture retrievals. All the ground-based observations were collected from test site-United States Department of Agriculture (USDA) OPE3, located a few miles away from NASA GSFC. Ground truth data were collected using a theta probe and in situ sensors which were then used for validation. Analysis

  14. Mitigation of ground motion effects via feedback systems in the Compact Linear Collider

    CERN Document Server

    Pfingstner, Jürgen; Schmickler, Hermann; Schulte, Daniel

    The Compact Linear Collider (CLIC) is a future multi-TeV electron positron collider, which is currently being designed at CERN. To achieve its ambitious goals, CLIC has to produce particle beams of the highest quality, which makes the accelerator very sensitive to ground motion. Four mitigation methods have been foreseen by the CLIC design group to cope with the feasibility issue of ground motion. This thesis is concerned with the design of one of these mitigation methods, named linac feedback (L-FB), but also with the simultaneous simulation and validation of all mitigation methods. Additionally, a technique to improve the quality of the indispensable system knowledge has been developed. The L-FB suppresses beam oscillations along the accelerator. Its design is based on the decoupling of the overall accelerator system into independent channels. For each channel an individual compensator is found with the help of a semi- automatic control synthesis procedure. This technique allows the designer to incorporate ...

  15. Measurement and simulation of ground-coupled air waves and diffracted infrasound from the Kokoxili Earthquake, 14th Nov. 2001

    Science.gov (United States)

    Guilbert, J.; Le Pichon, A.; Vallee, M.; Alcoverro, B.; Ulziibat, M.

    2002-12-01

    On November 14, 2001, a strong earthquake measuring Mm 7.8 occurred in the Qinghai Province (China). Coherent infrasonic waves were detected during more than one hour by the IS34 infrasound station in Mongolia (~1500 km from the epicenter). Using an appropriate acoustic propagation model, the inversion of the infrasonic measurements allows a precise localization of the secondary sources distribution along the Qinghai mountains. The predominant source of infrasound is likely ground-coupled air waves generated by the strong variations of topography due to energy carried out by surface seismic waves that travel from the epicenter region through the Qinghai mountains. To confirm the locations of these distant source regions, the pressure field has been reconstructed at IS34. For each element of the topography, a synthetic seismogram used as an input of the integral relation of Huygens-Rayleigh permits to estimate the pressure variation. The synthetic pressure field fit the recorded data in azimuth and in relative amplitude. These results confirm the hypothesis of a strong coupling between the Rayleigh waves and the atmosphere, as it has already been observed during the Arequipa earthquake of June 23rd 2001. The simulations also permit to validate the infrasonic propagation model. This favorable setting within a region of high mountains makes easier the evaluation of the relative contribution of the different source mechanisms involved in large earthquake.

  16. Toward simulating complex systems with quantum effects

    Science.gov (United States)

    Kenion-Hanrath, Rachel Lynn

    Quantum effects like tunneling, coherence, and zero point energy often play a significant role in phenomena on the scales of atoms and molecules. However, the exact quantum treatment of a system scales exponentially with dimensionality, making it impractical for characterizing reaction rates and mechanisms in complex systems. An ongoing effort in the field of theoretical chemistry and physics is extending scalable, classical trajectory-based simulation methods capable of capturing quantum effects to describe dynamic processes in many-body systems; in the work presented here we explore two such techniques. First, we detail an explicit electron, path integral (PI)-based simulation protocol for predicting the rate of electron transfer in condensed-phase transition metal complex systems. Using a PI representation of the transferring electron and a classical representation of the transition metal complex and solvent atoms, we compute the outer sphere free energy barrier and dynamical recrossing factor of the electron transfer rate while accounting for quantum tunneling and zero point energy effects. We are able to achieve this employing only a single set of force field parameters to describe the system rather than parameterizing along the reaction coordinate. Following our success in describing a simple model system, we discuss our next steps in extending our protocol to technologically relevant materials systems. The latter half focuses on the Mixed Quantum-Classical Initial Value Representation (MQC-IVR) of real-time correlation functions, a semiclassical method which has demonstrated its ability to "tune'' between quantum- and classical-limit correlation functions while maintaining dynamic consistency. Specifically, this is achieved through a parameter that determines the quantumness of individual degrees of freedom. Here, we derive a semiclassical correction term for the MQC-IVR to systematically characterize the error introduced by different choices of simulation

  17. Study of the Pierre Auger Observatory ground detectors: tests, simulation and calibration; Etude des detecteurs de surface de l'observatoire Pierre Auger: tests, simulation et etalonnage

    Energy Technology Data Exchange (ETDEWEB)

    Creusot, A

    2004-10-01

    The Pierre Auger Observatory is intended to the ultra high energy cosmic rays study. This study is realized through the particles showers coming from the interaction between the cosmic rays and the atmosphere. The ground detection of these showers requires a comprehensive understanding of the detectors. Several test tanks have been elaborated for this purpose, especially the Orsay one. The first chapter is dedicated to the presentation of the cosmic rays and of the Pierre Auger Observatory. The second one describes the detectors used for the Observatory surface array. The Orsay test tank is then presented and detailed. We study the results we have got with the Orsay test tank in the fourth chapter and compare these results with those of the Observatory detectors in the fifth chapter. The sixth chapter is dedicated to the validation of the results set through the simulation (GEANT4 software). Finally, the first detected particles showers are presented in the seventh chapter. The data acquisition has begun this year. The construction will be finished by end of 2005. From this moment, The Pierre Auger Observatory will allow us to contribute to solving the cosmic rays puzzle. (author)

  18. Ground Motion Prediction for the Vicinity by Using the Microtremor Site-effect Correction

    Science.gov (United States)

    Lin, C. M.; Wen, K. L.; Kuo, C. H.

    2015-12-01

    This study develops a method analyzing the seismograms of a strong-motion station and the microtremor site effects (H/V ratios) around it to predict the ground motion of its vicinity. The Hsinchu Science Park (HSP) in Taiwan was chosen as our study site. The horizontal S-wave seismograms of the TCU017 strong-motion station, which locates at the center of the HSP, were convoluted by the difference of the microtremor H/V ratio between various sites to synthesize the seismograms of several strong-motion stations around the HSP. The comparisons between synthetic and observed seismograms show that this method of ground motion prediction for the vicinity is feasible for far-field earthquakes. However, the seismic source and attenuation effects make this method ineffectual for near-field earthquakes. Because the microtremor H/V ratios at about 200 sites, which are densely distributed in the HSP, were conducted, the seismic ground motion distributions of some historical earthquakes were synthesized by this study. The synthetic ground motion distributions ignore the seismic source and attenuation effects but still show notable variations in the HSP because of the seismic site effects.

  19. Effect of low-temperature aging on the mechanical behavior of ground Y-TZP

    NARCIS (Netherlands)

    Pereira, G.K.R.; Amaral, M.; Cesar, P.F.; Bottino, M.C.; Kleverlaan, C.J.; Valandro, L.F.

    2015-01-01

    This study evaluated the effects of low-temperature aging on the surface topography, phase transformation, biaxial flexural strength, and structural reliability of a ground Y-TZP ceramic. Disc-shaped specimens were manufactured and divided according to two factors: "grinding" - without grinding

  20. A Grounded Theory Study of Effective Global Leadership Development Strategies: Perspectives from Brazil, India, and Nigeria

    Science.gov (United States)

    Lokkesmoe, Karen Jane

    2009-01-01

    This qualitative, grounded theory study focuses on global leadership and global leadership development strategies from the perspective of people from three developing countries, Brazil, India, and Nigeria. The study explores conceptualizations of global leadership, the skills required to lead effectively in global contexts, and recommended…

  1. Leading Effective Educational Technology in K-12 School Districts: A Grounded Theory

    Science.gov (United States)

    Hill, Lara Gillian C.

    2011-01-01

    A systematic grounded theory qualitative study was conducted investigating the process of effectively leading educational technology in New Jersey public K-12 school districts. Data were collected from educational technology district leaders (whether formal or non-formal administrators) and central administrators through a semi-structured online…

  2. Effects of Outdoor School Ground Lessons on Students' Science Process Skills and Scientific Curiosity

    Science.gov (United States)

    Ting, Kan Lin; Siew, Nyet Moi

    2014-01-01

    The purpose of this study was to investigate the effects of outdoor school ground lessons on Year Five students' science process skills and scientific curiosity. A quasi-experimental design was employed in this study. The participants in the study were divided into two groups, one subjected to the experimental treatment, defined as…

  3. Single Phase-to-Ground Fault Line Identification and Section Location Method for Non-Effectively Grounded Distribution Systems Based on Signal Injection

    Institute of Scientific and Technical Information of China (English)

    PAN Zhencun; WANG Chengshan; CONG Wei; ZHANG Fan

    2008-01-01

    A diagnostic signal current trace detecting based single phase-to-ground fault line identifica- tion and section location method for non-effectively grounded distribution systems is presented in thisi oaper. A special diagnostic signal current is injected into the fault distribution system, and then it is de- tected at the outlet terminals to identify the fault line and at the sectionalizing or branching point along the fault line to locate the fault section. The method has been put into application in actual distribution network and field experience shows that it can identify the fault line and locate the fault section correctly and effectively.

  4. Frozen Chemistry Effects on Nozzle Performance Simulations

    Science.gov (United States)

    Yoder, Dennis A.; Georgiadis, Nicholas J.; O'Gara, Michael R.

    2009-01-01

    Simulations of exhaust nozzle flows are typically conducted assuming the gas is calorically perfect, and typically modeled as air. However the gas inside a real nozzle is generally composed of combustion products whose thermodynamic properties may differ. In this study, the effect of gas model assumption on exhaust nozzle simulations is examined. The three methods considered model the nozzle exhaust gas as calorically perfect air, a calorically perfect exhaust gas mixture, and a frozen exhaust gas mixture. In the latter case the individual non-reacting species are tracked and modeled as a gas which is only thermally perfect. Performance parameters such as mass flow rate, gross thrust, and thrust coefficient are compared as are mean flow and turbulence profiles in the jet plume region. Nozzles which operate at low temperatures or have low subsonic exit Mach numbers experience relatively minor temperature variations inside the nozzle, and may be modeled as a calorically perfect gas. In those which operate at the opposite extreme conditions, variations in the thermodynamic properties can lead to different expansion behavior within the nozzle. Modeling these cases as a perfect exhaust gas flow rather than air captures much of the flow features of the frozen chemistry simulations. Use of the exhaust gas reduces the nozzle mass flow rate, but has little effect on the gross thrust. When reporting nozzle thrust coefficient results, however, it is important to use the appropriate gas model assumptions to compute the ideal exit velocity. Otherwise the values obtained may be an overly optimistic estimate of nozzle performance.

  5. Effect of Passive Pile on 3D Ground Deformation and on Active Pile Response

    OpenAIRE

    Bingxiang Yuan; Rui Chen; Jun Teng; Tao Peng; Zhongwen Feng

    2014-01-01

    Using a series of model tests, this study investigated the effect of a passive pile on 3D ground deformation around a laterally loaded pile and on that laterally loaded pile’s response in sand. The active pile head was subjected to lateral loads, and the passive pile was arranged in front of the active pile. In the model tests, the distance between the two pile centers was set to zero (i.e., a single pile test), 2.5, 4, and 6 times the pile width (B). The 3D ground surface deformations around...

  6. Viscous flowfields induced by three-dimensional lift jets in ground effect

    Science.gov (United States)

    Bower, W. W.

    1982-01-01

    The turbulent flowfields associated with single and multiple jets impinging on a ground plane are relevant to the aerodynamics of VTOL aircraft in ground effect. These flowfields are computed using the Reynolds equations and a two-equation turbulence model to describe an isolated jet and two interacting jets with fountain formation. Coordinate transformations are employed to apply the boundary conditions for the governing equations in the far field, and a third-order-accurate upwind-difference scheme is used to discretize the resulting system. Flowfield properties calculated for these impinging-jet configurations are presented and compared with experimental data.

  7. Effect of ship structure and size on grounding and collision damage distributions

    DEFF Research Database (Denmark)

    Pedersen, Preben Terndrup; Zhang, Shengming

    2000-01-01

    of the ship have the same probability density distributions regardless of a particular structural design and ship size.The present paper explores analytical methods for assessing the overall effect of structural design on the damage distributions in accidental grounding and collisions. The results...... of a larger relative damage length than that of a smaller ship in grounding damage. On the other hand, the damages to the side structure caused by ship collisions are found to be relatively smaller for large ships.The main conclusion is that the existing IMO damage distributions will severely underestimate...

  8. Ground-based simulation of the Earth's upper atmosphere oxygen impact on polymer composites with nanosized fillers

    Science.gov (United States)

    Novikov, Lev; Chernik, Vladimir; Voronina, Ekaterina; Chechenin, Nikolay; Samokhina, Maria S.; Bondarenko, Gennady G.; Gaidar, Anna I.; Vorobyeva, Ekaterina A.; Petrov, Dmitrii V.; Chirskaya, Natalia P.

    The improvement of durability of polymer composites to the space environment impact is a very important task because these materials are considered currently as very promising type of materials for aerospace engineering. By embedding various nanosized fillers into a polymer matrix it is possible to obtain composites with required mechanical, thermal, electrical and optic properties. However, while developing such materials for operation in low Earth orbits (LEO), it is necessary to study thoroughly their durability to the impact of atomic oxygen (AO) of the Earth’s upper atmosphere, because AO is the main factor that causes erosion and damage of spacecraft surface materials in LEO. Ground-based simulation of AO impact on polymer composites was performed on a magnetoplasmadynamic accelerator developed at Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University. Polymer composite samples which were prepared as films of 30-50 mum thickness with different amount (3-20 wt%) of various inorganic and organic nanofillers including nanoparticles of metal oxides and carbides as well as polyethoxysiloxanes and carbon nanotubes (CNTs), were exposed to hyperthermal AO flow, and mass losses of samples were estimated. Changes in the structure of composite surface and in material optical properties were studied. The experiments demonstrated that embedding nanosized fillers into a polymer matrix can significantly reduced mass losses, and the good dispersion of fillers improves AO durability in comparison with initial polymers [1]. The computer simulation within the developed 2D Monte-Carlo model demonstrated a good agreement with the experimental data [2]. Special attention was given to the study of AO impact on aligned multiwalled CNTs and CNT-based composites [3]. Some results of computer simulation of hyperthermal oxygen atom interaction with CNT and graphene as well as with polymers are presented to discuss elementary processes which occur in nanostructures

  9. Grounding Action Words in the Sensorimotor Interaction with the World: Experiments with a Simulated iCub Humanoid Robot.

    Science.gov (United States)

    Marocco, Davide; Cangelosi, Angelo; Fischer, Kerstin; Belpaeme, Tony

    2010-01-01

    This paper presents a cognitive robotics model for the study of the embodied representation of action words. The present research will present how an iCub humanoid robot can learn the meaning of action words (i.e. words that represent dynamical events that happen in time) by physically interacting with the environment and linking the effects of its own actions with the behavior observed on the objects before and after the action. The control system of the robot is an artificial neural network trained to manipulate an object through a Back-Propagation-Through-Time algorithm. We will show that in the presented model the grounding of action words relies directly to the way in which an agent interacts with the environment and manipulates it.

  10. Grounding action words in the sensorimotor interaction with the world: experiments with a simulated iCub humanoid robot

    Directory of Open Access Journals (Sweden)

    Davide Marocco

    2010-05-01

    Full Text Available This paper presents a cognitive robotics model for the study of the embodied representation of action words. The present research will present how a iCub humanoid robot can learn the meaning of action words (i.e. words that represent dynamical events that happen in time by physically acting on the environment and linking the effects of its own actions with the behaviour observed on the objects before and after the action. The control system of the robot is an artificial neural network trained to manipulate an object through a Back-Propagation Through Time algorithm. We will show that in the presented model the grounding of action words relies directly to the way in which an agent interacts with the environment and manipulates it.

  11. Greenhouse effect simulator - An educational application

    Science.gov (United States)

    Machado, Alan Freitas; Viveiros, Bruno Martins; da Silva, Claudio Elias

    2016-12-01

    Using the program "Modellus", we intend to create a simple simulation to show the impacts that the Greenhouse Effect might have, in a didactic and friendly way, in order to expose this notions to high and middle school students. In order to do so, we created a program that will simulate a sweep, through the Troposphere, and create two lines in a graphic, one showing the temperatures behavior, in normal conditions, and the other showing how the temperature behaves in the presence of excess of Greenhouse gases. The main purpose of the project is to use the model in schools and try to make kids more conscious of their roles in our so society, showing them the consequences of the tendency of our acts, stimulating them to be more proactives to change the future.

  12. The anti-obesity effect of natural vanadium-containing Jeju ground water.

    Science.gov (United States)

    Park, Seon-Joo; Youn, Cha-Kyung; Hyun, Jin Won; You, Ho Jin

    2013-02-01

    This study investigated the anti-obesity effects of Jeju ground water containing the vanadium components S1 (8.0 ± 0.9 μg/l) and S3 (26.0 ± 2.09 μg/l) on the differentiation of 3 T3-L1 preadipocytes and obesity in mice that were fed a high-fat diet (HFD). The 3 T3-L1 preadipocyte cells were cultured and differentiated in media consisting of Jeju ground water (S1, S3) or deionized water (DW) containing dexamethasone, isobutylmethylxanthine, and insulin. Oil Red O staining showed that lipid accumulation was attenuated in adipocyte cells treated with Jeju ground water. S3 significantly decreased peroxisome-activated receptor γ and CCAAT-enhancer-binding protein α mRNA expression levels, which play major roles in the transcriptional control of adipogenesis, compared to DW. Furthermore, mRNA expression levels of targeted genes, such as adipocyte fatty acid, lipoprotein lipase, and leptin, were decreased by S3 treatment compared with the control group. In mice with HFD-induced obesity, Jeju ground water decreased HFD-induced body weight gain and reduced total cholesterol, triglyceride, and glucose levels in the plasma compared to control mice. Taken together, Jeju ground water inhibits preadipocyte differentiation and adipogenesis in obesity animal models.

  13. Temperature and energy deficit in the ground during operation and recovery phases of closed-loop ground source heat pump system: Effect of the groundwater flow

    Science.gov (United States)

    Erol, Selcuk; Francois, Bertrand

    2016-04-01

    The advection/dispersion mechanism of the groundwater flow in the ground has a significant effect on a borehole heat exchanger (BHE) to enhance its thermal performance. However, the amount of energy extracted from the ground never disappears and only shifts with the magnitude of the effective thermal velocity in the infinite domain. In this work, we focus on the temperature and the energy balance of the ground in an advection/dispersion dominated heat transfer system during the operation period of a BHE and the subsequent recovery phase when the system is idle. The problem is treated with single BHE and multi-BHEs systems, for different representative geology and different groundwater flow velocity. In order to assess the thermal energy deficit due to heat extraction from the ground, we used the finite line source analytical model, developed recently (Erol et al., 2015) that provides the temperature distributions around the boreholes for discontinuous heat extraction. The model is developed based on the Green's function, which is the solution of heat conduction/advection/dispersion equation in porous media, for discontinuous heat extraction by analytically convoluting rectangular function or pulses in time domain. The results demonstrate the significant positive impact of the groundwater flow for the recovery in terms of temperature deficit at the location of the borehole. However, the total thermal energy deficit is not affected by the groundwater movement. The energy balance of the ground is the same no matter the prevailing heat transfer system, which can be only conduction or advection/dispersion. In addition, the energy balance of the ground is not based on either the duration of the production period operation or of the recovery phase, but depends on the total amount of heat that is extracted and on the bulk volumetric heat capacity of the ground.

  14. Simulation and design of ground source heat pump systems%地源热泵系统的模拟与设计

    Institute of Scientific and Technical Information of China (English)

    JeffreyD.Spitler; CenkYavuzturk; 等

    2003-01-01

    总结了近年来地源热泵系统的模拟和设计方面的研究和进展.首先给出了地源热泵系统各部件建模方面的进展,包括竖直埋管地热换热器、单井循环系统以及在地源热泵混合系统中采用的几种辅助散热装置.其次,讨论现场测定深层岩土热物性的技术.第三,介绍竖直埋管地热换热器的设计方法.最后,给出在设计地源热泵系统中采用系统模拟的几个应用实例.%This paper gives an overview of recent research and developments in ground source heat pump system simulation and design. First, developments related to modeling of components of the Ground Source Heat Pump (GSHP) system are presented-vertical ground loop heat exchanger, water source heat pump, standing column well, and several types of supplemental heat rejecters used in hybrid GSHP systems. Second, in situ measurement techniques for ground thermal properties are discussed. Third, a methodology for the design of the vertical ground loop heat exchanger is introduced. Last, several applications of using system simulation in the design of GSHP systems are presented.

  15. Experimental Study of Ground Effect on Three-Dimensional Insect-Like Flapping Motion

    Science.gov (United States)

    Zhang, Xiaohu; Lua, Kim Boon; Chang, Rong; Lim, Tee Tai; Yeo, Khoon Seng

    2014-11-01

    This paper focuses on an experimental investigation aimed at evaluating the aerodynamics force characteristics of three-dimensional (3D) insect-like flapping motion in the vicinity of ground. The purpose is to establish whether flapping wing insects can derive aerodynamic benefit from ground effect similar to that experienced by a fixed wing aircraft. To evaluate this, force measurements were conducted in a large water tank using a 3D flapping mechanism capable of executing various insect flapping motions. Here, we focus on three types of flapping motions, namely simple harmonic flapping motion, hawkmoth-like hovering motion and fruitfly-like hovering motion, and two types of wing planforms (i.e. hawkmoth-like wing and fruitfly-like wing). Results show that hawkmoth-like wing executing simple harmonic flapping motion produces average lift to drag ratio (\\bar C\\bar L/\\bar C\\bar D) similar to that of fruitfly wing executing the same motion. In both cases, they are relatively independent of the wing distance from the ground. On the other hand, a hawkmoth wing executing hawkmoth flapping motion produces (\\bar C\\bar L/\\bar C\\bar D) characteristic different from that of fruitfly wing executing fruitfly motion. While the (\\bar C\\bar L/\\bar C\\bar D) value of the former is a function of the wing distance from the ground, the latter is minimally affected by ground effect. Unlike fixed wing aerodynamics, all the flapping wing cases considered here do not show a monotonic increase in (\\bar C\\bar L/\\bar C\\bar D) with decreasing wing distance from the ground.

  16. Statistical evaluation of effects of riparian buffers on nitrate and ground water quality

    Science.gov (United States)

    Spruill, T.B.

    2000-01-01

    A study was conducted to statistically evaluate the effectiveness of riparian buffers for decreasing nitrate concentrations in ground water and for affecting other chemical constituents. Values for pH, specific conductance, alkalinity, dissolved organic carbon (DOC), silica, ammonium, phosphorus, iron, and manganese at 28 sites in the Contentnea Creek Basin were significantly higher (p 20 yr) discharging ground water draining areas with riparian buffers compared with areas without riparian buffers. No differences in chloride, nitrate nitrogen, calcium, sodium, and dssolved oxygen concentrations in old ground water between buffer and nonbuffer areas were detected. Comparison of samples of young (20 yr) discharging ground water draining areas with riparian buffers compared with areas without riparian buffers. No differences in chloride, nitrate nitrogen, calcium, sodium, and dissolved oxygen concentrations in old ground water between buffer and nonbuffer areas were detected. Comparison of samples of young (water samples from buffer and nonbuffer areas indicated significantly higher specific conductance, calcium, chloride, and nitrate nitrogen in nonbuffer areas. Riparian buffers along streams can affect the composition of the hyporheic zone by providing a source of organic carbon to the streambed, which creates reducing geochemical conditions that consequently can affect the chemical quality of old ground water discharging through it. Buffer zones between agricultural fields and streams facilitate dilution of conservative chemical constituents in young ground water that originate from fertilizer applications and also allow denitrification in ground water by providing an adequate source of organic carbon generated by vegetation in the buffer zone. Based on the median chloride and nitrate values for young ground water in the Contentnea Creek Basin, nitrate was 95% lower in buffer areas compared with nonbuffer areas, with a 30 to 35% reduction estimated to be due to

  17. 新型混合地源热泵的土壤热平衡性能模拟%Soil Thermal Balance Performance Simulation of the New Hybrid Ground Source Heat Pump

    Institute of Scientific and Technical Information of China (English)

    刘小银; 彭彪

    2015-01-01

    Ground source heat pump is a new kind of green energy technologies which is advantage in energy conservation and environmental protection. O ne of the severe problems in the process of application is the thermal imbalance of the heat absorption and release to the ground. To solve this problem, this paper presents a new type of hybrid ground source heat pump in which hot w ater systemis combined with air conditioning systemof ground source heat pump. As an example, make a simulation of a new ly designed air conditioning systemof a hotel in Changsha. By comparison of the conventional single ground source heat pump, this new hybrid ground source heat pump has been confirmed to solve the imbalance of the heat absorption and release to the ground, effectively improved the operation efficiency ofairconditioning unitmean while.%地源热泵是一种新型节能环保的绿色能源利用技术,在应用过程中,存在的较大问题之一就是对土壤的吸放热不平衡。针对此问题本文提出了一种新的混合地源热泵形式,将热水系统和地源热泵空调系统进行耦合,对长沙某宾馆进行了系统设计并用T R N SY S进行了长达30年的模拟。通过和传统单一的地源热泵空调系统比较,证实了该系统不仅能有效地解决土壤吸放热不平衡问题,而且有效地提高了机组的运行效率。

  18. Effect of spatial coherence on laser beam self-focusing from orbit to the ground in the atmosphere.

    Science.gov (United States)

    Deng, Hanling; Ji, Xiaoling; Li, Xiaoqing; Zhang, Hao; Wang, Xianqu; Zhang, Yuqiu

    2016-06-27

    The effect of spatial coherence on laser beam self-focusing in the atmosphere to assist delivering powerful laser beams from orbit to the ground is studied. It is found that a fully coherent beam is more strongly compressed on the ground than a partially (spatial) coherent beam (PCB), even so, for a PCB the compressed spot size on the ground may be reduced below the diffraction limit due to self-focusing effect, and a PCB has higher threshold critical power than a fully coherent beam. Furthermore, an effective design rule for maximal compression without beam splitting of the transported PCB from orbit to the ground is presented.

  19. Effects of simulated acid rain on vegetation

    Energy Technology Data Exchange (ETDEWEB)

    Ferenbaugh, R.W.

    1974-01-01

    Experiments were performed to determine the effects of simulated acid rain on Chenopodium quinoa, Hordeum vulgare and Phaseolus vulgaris. Because of differential species' susceptibility, detailed experiments were conducted only on Phaseolus vulgaris. Acid rain was simulated by spraying the plants with a hand-held atomizer. Sulfuric acid solutions covering a pH range of 1.5 to 3.5 in one half pH unit increments were used. Gross morphological effects noted at lower pH values included failure to attain normal height, necrosis and wrinkling of leaves, excessive and adventitious budding, and premature abscission of primary leaves. Histological effects included smaller cell size, a decreased amount of intercellular space, hypertrophied nuclei and nucleoli, and a reduction in the size of starch granules within the chloroplasts. Dry weight remained an approximately constant percentage of fresh weight, and chlorophyll analyses showed that both chlorophyll concentration and ratio of chlorophyll 'a' to chlorophyll 'b' also remained constant. Respirometer studies showed that, while respiration rate increased only slightly at low pH values, photosynthetic rate increased dramatically. Quantitative analyses indicated that carbohydrate content was reduced at low pH values, with starch content reduced much more than sugar content. Root biomass was also reduced at low pH values. Application of Congo red indicator solution to the acid treated tissue showed that it was being acidified to a pH of below 4. 114 references, 23 figures, 12 tables.

  20. Retrievals of formaldehyde from ground-based FTIR and MAX-DOAS observations at the Jungfraujoch station and comparisons with GEOS-Chem and IMAGES model simulations

    Science.gov (United States)

    Franco, B.; Hendrick, F.; Van Roozendael, M.; Müller, J.-F.; Stavrakou, T.; Marais, E. A.; Bovy, B.; Bader, W.; Fayt, C.; Hermans, C.; Lejeune, B.; Pinardi, G.; Servais, C.; Mahieu, E.

    2015-04-01

    As an ubiquitous product of the oxidation of many volatile organic compounds (VOCs), formaldehyde (HCHO) plays a key role as a short-lived and reactive intermediate in the atmospheric photo-oxidation pathways leading to the formation of tropospheric ozone and secondary organic aerosols. In this study, HCHO profiles have been successfully retrieved from ground-based Fourier transform infrared (FTIR) solar spectra and UV-visible Multi-AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) scans recorded during the July 2010-December 2012 time period at the Jungfraujoch station (Swiss Alps, 46.5° N, 8.0° E, 3580 m a.s.l.). Analysis of the retrieved products has revealed different vertical sensitivity between both remote sensing techniques. Furthermore, HCHO amounts simulated by two state-of-the-art chemical transport models (CTMs), GEOS-Chem and IMAGES v2, have been compared to FTIR total columns and MAX-DOAS 3.6-8 km partial columns, accounting for the respective vertical resolution of each ground-based instrument. Using the CTM outputs as the intermediate, FTIR and MAX-DOAS retrievals have shown consistent seasonal modulations of HCHO throughout the investigated period, characterized by summertime maximum and wintertime minimum. Such comparisons have also highlighted that FTIR and MAX-DOAS provide complementary products for the HCHO retrieval above the Jungfraujoch station. Finally, tests have revealed that the updated IR parameters from the HITRAN 2012 database have a cumulative effect and significantly decrease the retrieved HCHO columns with respect to the use of the HITRAN 2008 compilation.

  1. Retrievals of formaldehyde from ground-based FTIR and MAX-DOAS observations at the Jungfraujoch station and comparisons with GEOS-Chem and IMAGES model simulations

    Directory of Open Access Journals (Sweden)

    B. Franco

    2015-04-01

    Full Text Available As an ubiquitous product of the oxidation of many volatile organic compounds (VOCs, formaldehyde (HCHO plays a key role as a short-lived and reactive intermediate in the atmospheric photo-oxidation pathways leading to the formation of tropospheric ozone and secondary organic aerosols. In this study, HCHO profiles have been successfully retrieved from ground-based Fourier transform infrared (FTIR solar spectra and UV-visible Multi-AXis Differential Optical Absorption Spectroscopy (MAX-DOAS scans recorded during the July 2010–December 2012 time period at the Jungfraujoch station (Swiss Alps, 46.5° N, 8.0° E, 3580 m a.s.l.. Analysis of the retrieved products has revealed different vertical sensitivity between both remote sensing techniques. Furthermore, HCHO amounts simulated by two state-of-the-art chemical transport models (CTMs, GEOS-Chem and IMAGES v2, have been compared to FTIR total columns and MAX-DOAS 3.6–8 km partial columns, accounting for the respective vertical resolution of each ground-based instrument. Using the CTM outputs as the intermediate, FTIR and MAX-DOAS retrievals have shown consistent seasonal modulations of HCHO throughout the investigated period, characterized by summertime maximum and wintertime minimum. Such comparisons have also highlighted that FTIR and MAX-DOAS provide complementary products for the HCHO retrieval above the Jungfraujoch station. Finally, tests have revealed that the updated IR parameters from the HITRAN 2012 database have a cumulative effect and significantly decrease the retrieved HCHO columns with respect to the use of the HITRAN 2008 compilation.

  2. Is ground cover vegetation an effective biological control enhancement strategy against olive pests?

    Directory of Open Access Journals (Sweden)

    Daniel Paredes

    Full Text Available Ground cover vegetation is often added or allowed to generate to promote conservation biological control, especially in perennial crops. Nevertheless, there is inconsistent evidence of its effectiveness, with studies reporting positive, nil or negative effects on pest control. This might arise from differences between studies at the local scale (e.g. orchard management and land use history, the landscape context (e.g. presence of patches of natural or semi-natural vegetation near the focal orchard, or regional factors, particularly climate in the year of the study. Here we present the findings from a long-term regional monitoring program conducted on four pest species (Bactrocera oleae, Prays oleae, Euphyllura olivina, Saissetia oleae in 2,528 olive groves in Andalusia (Spain from 2006 to 2012. Generalized linear mixed effect models were used to analyze the effect of ground cover on different response variables related to pest abundance, while accounting for variability at the local, landscape and regional scales. There were small and inconsistent effects of ground cover on the abundance of pests whilst local, landscape and regional variability explained a large proportion of the variability in pest response variables. This highlights the importance of local and landscape-related variables in biological control and the potential effects that might emerge from their interaction with practices, such as groundcover vegetation, implemented to promote natural enemy activity. The study points to perennial vegetation close to the focal crop as a promising alternative strategy for conservation biological control that should receive more attention.

  3. Is ground cover vegetation an effective biological control enhancement strategy against olive pests?

    Science.gov (United States)

    Paredes, Daniel; Cayuela, Luis; Gurr, Geoff M; Campos, Mercedes

    2015-01-01

    Ground cover vegetation is often added or allowed to generate to promote conservation biological control, especially in perennial crops. Nevertheless, there is inconsistent evidence of its effectiveness, with studies reporting positive, nil or negative effects on pest control. This might arise from differences between studies at the local scale (e.g. orchard management and land use history), the landscape context (e.g. presence of patches of natural or semi-natural vegetation near the focal orchard), or regional factors, particularly climate in the year of the study. Here we present the findings from a long-term regional monitoring program conducted on four pest species (Bactrocera oleae, Prays oleae, Euphyllura olivina, Saissetia oleae) in 2,528 olive groves in Andalusia (Spain) from 2006 to 2012. Generalized linear mixed effect models were used to analyze the effect of ground cover on different response variables related to pest abundance, while accounting for variability at the local, landscape and regional scales. There were small and inconsistent effects of ground cover on the abundance of pests whilst local, landscape and regional variability explained a large proportion of the variability in pest response variables. This highlights the importance of local and landscape-related variables in biological control and the potential effects that might emerge from their interaction with practices, such as groundcover vegetation, implemented to promote natural enemy activity. The study points to perennial vegetation close to the focal crop as a promising alternative strategy for conservation biological control that should receive more attention.

  4. Effect of spin-orbit coupling on the ground state structure of mercury

    Science.gov (United States)

    Mishra, Vinayak; Gyanchandani, Jyoti; Chaturvedi, Shashank; Sikka, S. K.

    2014-05-01

    Near zero kelvin ground state structure of mercury is the body centered tetragonal (BCT) structure (β Hg). However, in all previously reported density functional theory (DFT) calculations, either the rhombohedral or the HCP structure has been found to be the ground state structure. Based on the previous calculations it was predicted that the correct treatment of the SO effects would improve the result. We have performed FPLAPW calculations, with and without inclusion of the SO coupling, for determining the ground state structure. These calculations determine rhombohedral structure as the ground state structure instead of BCT structure. The calculations, without inclusion of SO effect, predict that the energies of rhombohedral and BCT structures are very close to each other but the energy of rhombohedral structure is lower than that of BCT structure at ambient as well as high pressure. On the contrary, the SO calculations predict that though at ambient conditions the rhombohedral structure is the stable structure but on applying a pressure of 3.2 GPa, the BCT structure becomes stable. Hence, instead of predicting the stability of BCT structure at zero pressure, the SO calculations predict its stability at 3.2 GPa. This small disagreement is expected when the energy differences between the structures are small.

  5. Ground Freezing Fog Simulation Technology Study%开放式结冰条件模拟技术研究

    Institute of Scientific and Technical Information of China (English)

    李志茂; 李革萍; 王大伟; 沈东

    2013-01-01

    在-1~-9益的环境温度条件下,采用开放式结冰条件模拟技术可以为民机或军机发动机短舱防冰系统性能试验模拟出合适的结冰气象条件。采用气液两相喷嘴模拟水雾结冰环境时,所采用气体和液体的纯度是过冷水滴产生的先决条件,气液两相压差、风洞吹风速度和试验对象距离是影响结冰气象参数的关键因子。采用改造后的FM-100传感器可实现对结冰气象参数的实时测量。通过升降机构、小角度俯仰和万向轮等辅助结构设计,开放式结冰条件模拟系统可以满足不同试验对象的试验要求,可以适应不同风向的试验环境,具备非常广阔的推广应用前景。%Ground freezing fog simulation technology can generate icing condition for commercial or military air-craft nacelle anti-ice system performance evaluation under -1~-9℃. Purity of water and air used for fog genera-ting is the precondition, icing parameter is impacted by diff-pressure of liquid-gas, wind tunnel velocity and dis-tance between test article and test rig. Rectified FM-100 sensor can be used for icing parameter measurement, rig lift, small angle pitching and universal mechanical structure design make the fog simulation rig can satisfy the re-quirements of different test articles and wind directions.

  6. Effect Of Long-Period Earthquake Ground Motions On Nonlinear Vibration Of Shells With Variable Thickness

    Science.gov (United States)

    Abdikarimov, R.; Bykovtsev, A.; Khodzhaev, D.; Research Team Of Geotechnical; Structural Engineers

    2010-12-01

    Long-period earthquake ground motions (LPEGM) with multiple oscillations have become a crucial consideration in seismic hazard assessment because of the rapid increase of tall buildings and special structures (SP).Usually, SP refers to innovative long-span structural systems. More specifically, they include many types of structures, such as: geodesic showground; folded plates; and thin shells. As continuation of previous research (Bykovtsev, Abdikarimov, Khodzhaev 2003, 2010) analysis of nonlinear vibrations (NV) and dynamic stability of SP simulated as shells with variable rigidity in geometrically nonlinear statement will be presented for two cases. The first case will represent NV example of a viscoelastic orthotropic cylindrical shell with radius R, length L and variable thickness h=h(x,y). The second case will be NV example of a viscoelastic shell with double curvature, variable thickness, and bearing the concentrated masses. In both cases we count, that the SP will be operates under seismic load generated by LPEGM with multiple oscillations. For different seismic loads simulations, Bykovtsev’s Model and methodology was used for generating LPEGM time history. The methodology for synthesizing LPEGM from fault with multiple segmentations was developed by Bykovtev (1978-2010) and based on 3D-analytical solutions by Bykovtsev-Kramarovskii (1987&1989) constructed for faults with multiple segmentations. This model is based on a kinematics description of displacement function on the fault and included in consideration of all possible combinations of 3 components of vector displacement (two slip vectors and one tension component). The opportunities to take into consideration fault segmentations with both shear and tension vector components of displacement on the fault plane provide more accurate LPEGM evaluations. Radiation patterns and directivity effects were included in the model and more physically realistic results for simulated LPEGM were considered. The

  7. Effect of mustard seed and sodium isoascorbate on lipid oxidation and colour of ground beef

    Directory of Open Access Journals (Sweden)

    Małgorzata Karwowska

    2013-12-01

    Full Text Available The aim of this study was to determine the effectiveness of the mustard seed in reducing lipid oxidation in ground beef compared to sodium isoascorbate. The research material were meat samples, prepared in four variants. The differentiating addition was ground white mustard (Sinapis alba, used in the native and autoclaved form. Reference were a control sample and a sample with the addition of sodium isoascorbate. The following were assayed during the study: TBARS value, redox potential, pH and colour parameters CIE L*a*b*. The addition of mustard had no effect on the pH value in comparison to the control sample and sodium isoascorbate. It has been shown that the use of mustard either native and autoclaved, decreased the value of TBARS ratio, and showed a similar effectiveness in preventing the oxidation of lipids as sodium isoascorbate.

  8. Species composition and fire: non-additive mixture effects on ground fuel flammability

    Directory of Open Access Journals (Sweden)

    Cassandra eVan Altena

    2012-04-01

    Full Text Available Biodiversity effects on many aspects of ecosystem function have been well documented. However, fire is an exception: fire experiments have mainly included single species, bulk litter, or vegetation, and, as such, the role of biodiversity as a determinant of flammability, a crucial aspect of ecosystem function, is poorly understood. This study is the first to experimentally test whether flammability characteristics of two-species mixtures are non-additive, i.e. differ from expected flammability based on the component species in monoculture. In standardized fire experiments on ground fuels, including monocultures and mixtures of five contrasting subarctic plant fuel types in a controlled laboratory environment, we measured flame speed, flame duration and maximum temperature. Broadly half of the mixture combinations showed non-additive effects for these flammability indicators; these were mainly enhanced dominance effects, where the fuel types with the more flammable value for a characteristic determined the flammability of the whole mixture. The high incidence of species non-additive effects on ground fuel flammability suggest that the combinations of fuel types may have important effects on ground fire regimes in vegetations differing or changing in species composition.

  9. Effects of advertising billboards during simulated driving.

    Science.gov (United States)

    Edquist, Jessica; Horberry, Tim; Hosking, Simon; Johnston, Ian

    2011-05-01

    There is currently a great deal of interest in the problem of driver distraction. Most research focuses on distractions from inside the vehicle, but drivers can also be distracted by objects outside the vehicle. Major roads are increasingly becoming sites for advertising billboards, and there is little research on the potential effects of this advertising on driving performance. The driving simulator experiment presented here examines the effects of billboards on drivers, including older and inexperienced drivers who may be more vulnerable to distractions. The presence of billboards changed drivers' patterns of visual attention, increased the amount of time needed for drivers to respond to road signs, and increased the number of errors in this driving task.

  10. Experimental Analysis on Shielding Effect of the Grounding Electrodes Under Impulse-current%冲击电流下接地极屏蔽效应的试验研究

    Institute of Scientific and Technical Information of China (English)

    杨财伟; 司马文霞; 袁涛

    2008-01-01

    Generally, the flow of a lightning impulse current from a grounding electrode into ground is a very complicated process determined by many factors. In order to analyze the mechanism of the impulse current dissipating in the earth from grounding electrode, the experiments that had been carried out by other authors almost used a single horizontal grounding wire or vertical grounding rod for sake of simplicity. However, in practical conditions, most of the grounding systems are constructed of grounding electrodes with branches in different directions. In this study, basing on the principle of dimensional similarity, impulse simulation experiments are performed on the common ground electrodes with conductor branches. This paper focuses on analyzing the impulse current dispersal regularity of different branches when injecting at one point. Comparing with the leakage current distribution of a single ground electrode, it is found that the leakage currents along the branches increase with the distance to the current feed point, and the more conductors near the injection point, the more uneven the leakage current distribution is. This work indicates that shielding effect should be taken into account when analyzing the impulse characteristics of grounding electrodes.

  11. Atmospheric effects on infrared measurements at ground level: Application to monitoring of transport infrastructures

    Science.gov (United States)

    Boucher, Vincent; Dumoulin, Jean

    2014-05-01

    Being able to perform easily non-invasive diagnostics for surveillance and monitoring of critical transport infrastructures is a major preoccupation of many technical offices. Among all the existing electromagnetic methods [1], long term thermal monitoring by uncooled infrared camera [2] is a promising technique due to its dissemination potential according to its low cost on the market. Nevertheless, Knowledge of environmental parameters during measurement in outdoor applications is required to carry out accurate measurement corrections induced by atmospheric effects at ground level. Particularly considering atmospheric effects and measurements in foggy conditions close as possible to those that can be encountered around transport infrastructures, both in visible and infrared spectra. In the present study, atmospheric effects are first addressed by using data base available in literature and modelling. Atmospheric attenuation by particles depends greatly of aerosols density, but when relative humidity increases, water vapor condenses onto the particulates suspended in the atmosphere. This condensed water increases the size of the aerosols and changes their composition and their effective refractive index. The resulting effect of the aerosols on the absorption and scattering of radiation will correspondingly be modified. In a first approach, we used aerosols size distributions derived from Shettle and Fenn [3] for urban area which could match some of experimental conditions encountered during trials on transport infrastructures opened to traffic. In order to calculate the influence of relative humidity on refractive index, the Hänel's model [4] could be used. The change in the particulate size is first related to relative humidity through dry particle radius, particle density and water activity. Once the wet aerosol particle size is found, the effective complex refractive index is the volume weighted average of the refractive indexes of the dry aerosol substance

  12. Pilot Study on the Effect of Grounding on Delayed-Onset Muscle Soreness

    Science.gov (United States)

    Brown, Dick; Hill, Michael

    2010-01-01

    Abstract Objectives The purpose of this pilot study was to determine whether there are markers that can be used to study the effects of grounding on delayed-onset muscle soreness (DOMS). Design and subjects Eight (8) healthy subjects were exposed to an eccentric exercise that caused DOMS in gastrocnemius muscles of both legs. Four (4) subjects were grounded with electrode patches and patented conductive sheets connected to the earth. Four (4) control subjects were treated identically, except that the grounding systems were not connected to the earth. Outcome measures Complete blood counts, blood chemistry, enzyme chemistry, serum and saliva cortisols, magnetic resonance imaging and spectroscopy and pain levels were taken at the same time of day before the eccentric exercise and 24, 48, and 72 hours afterwards. Parameters consistently differing by 10% or more, normalized to baseline, were considered worthy of further study. Results Parameters that differed by these criteria included white blood cell counts, bilirubin, creatine kinase, phosphocreatine/inorganic phosphate ratios, glycerolphosphorylcholine, phosphorylcholine, the visual analogue pain scale, and pressure measurements on the right gastrocnemius. Conclusions In a pilot study, grounding the body to the earth alters measures of immune system activity and pain. Since this is the first intervention that appears to speed recovery from DOMS, the pilot provides a basis for a larger study. PMID:20192911

  13. Kin effects on energy allocation in group-living ground squirrels.

    Science.gov (United States)

    Viblanc, Vincent A; Saraux, Claire; Murie, Jan O; Dobson, F Stephen

    2016-09-01

    The social environment has potent effects on individual phenotype and fitness in group-living species. We asked whether the presence of kin might act on energy allocation, a central aspect of life-history variation. Using a 22-year data set on reproductive and somatic allocations in Columbian ground squirrels (Urocitellus columbianus), we tested the effects of co-breeding and non-breeding kin on the fitness and energy allocation balance between reproduction and personal body condition of individual females. Greater numbers of co-breeding kin had a positive effect on the number of offspring weaned, through the mechanism of altering energy allocation patterns. On average, females with higher numbers of co-breeding kin did not increase energy income but biased energy allocation towards reproduction. Co-breeding female kin ground squirrels maintain close nest burrows, likely providing a social buffer against territorial invasions from non-kin ground squirrels. Lower aggressiveness, lower risks of infanticide from female kin and greater protection of territorial boundaries may allow individual females to derive net fitness benefits via their energy allocation strategies. We demonstrated the importance of kin effects on a fundamental life-history trade-off.

  14. 小波变换在地震动模拟中应用研究%Research on application of wavelet transform in ground motion simulation

    Institute of Scientific and Technical Information of China (English)

    宋志勇

    2012-01-01

    The study explores the nonstationarity in the simulation of random ground motion,simulates the nonstationarity feature of the ground motion by adopting the wavelet transform and analyzing all sorts of frequency components in the ground motion,and utilizing the relationship between the wavelet coefficients and the power spectral density function,and indicates it is more consistent with the factual ground motion by comparing its with the traditional stable analyzing models,so as to lay the foundation for further research.%对模拟随机地震动的非平稳性进行了探讨,利用小波变换,通过分析地震动中各频率成分,利用小波系数与功率谱密度函数的关系模拟地震动的非平稳特性,和传统的平稳分析模型相比,更符合地震动实际,为进一步研究奠定了基础。

  15. Modeled ground water age distributions

    Science.gov (United States)

    Woolfenden, Linda R.; Ginn, Timothy R.

    2009-01-01

    The age of ground water in any given sample is a distributed quantity representing distributed provenance (in space and time) of the water. Conventional analysis of tracers such as unstable isotopes or anthropogenic chemical species gives discrete or binary measures of the presence of water of a given age. Modeled ground water age distributions provide a continuous measure of contributions from different recharge sources to aquifers. A numerical solution of the ground water age equation of Ginn (1999) was tested both on a hypothetical simplified one-dimensional flow system and under real world conditions. Results from these simulations yield the first continuous distributions of ground water age using this model. Complete age distributions as a function of one and two space dimensions were obtained from both numerical experiments. Simulations in the test problem produced mean ages that were consistent with the expected value at the end of the model domain for all dispersivity values tested, although the mean ages for the two highest dispersivity values deviated slightly from the expected value. Mean ages in the dispersionless case also were consistent with the expected mean ages throughout the physical model domain. Simulations under real world conditions for three dispersivity values resulted in decreasing mean age with increasing dispersivity. This likely is a consequence of an edge effect. However, simulations for all three dispersivity values tested were mass balanced and stable demonstrating that the solution of the ground water age equation can provide estimates of water mass density distributions over age under real world conditions.

  16. Effect of structural disorder on the ground state properties of Co2CrAl Heusler alloy

    Science.gov (United States)

    Zagrebin, Mikhail A.; Sokolovskiy, Vladimir V.; Buchelnikov, Vasiliy D.; Pavlukhina, Oksana O.

    2017-08-01

    In order to discuss the difference between the available theoretical and experimental values of the total magnetic moment of Co2CrAl Heusler alloy, in this paper we studied the effects of a structural disorder on the magnetic and electronic ground state properties of the alloy studied by means of ab initio and Monte Carlo methods. On the one hand, it is shown that a calculated magnetic ground state of the austenite L21 structure is ferromagnetic, and the alloy demonstrates half-metallic behavior. However, the equilibrium lattice parameter and magnetic moment calculated for ferrimagnetic state (where the Cr atoms are ordered antiferromagnetically) are in better agreement with the available experimental data than the ferromagnetic one. On the other hand, an account of a structural disorder results in a decrease in the magnetic moment to a value close to the experimental. However, systems with a structural disorder are energetically unfavorable in comparison with the ordered L21 structure at zero temperature. Using the calculated exchange coupling parameters in the Heisenberg Hamiltonian, the temperature dependences of magnetization, specific heat, magnetic part of internal energy as well as Helmholtz energy are simulated in the framework of Monte Carlo technique for both ordered and disordered cases. Eventually, it is shown that the disordered structure with smaller magnetization is more stable at higher temperatures. This indicates that the experimental compound might be disordered.

  17. The antioxidant epazote effect (Chenopodium ambrosioides L.) on raw ground beef

    OpenAIRE

    Luz H. Villalobos-Delgado; Edith G. Gonzalez-Mondragon; Alma Yadira Salazar-Govea; Joaquin T. Santiago-Castro; Juana Ramirez-Andrade

    2016-01-01

    For this paper, solid-liquid extractions of epazote (Chenopodium ambrosioides L.) were carried out using water (IE) and ethanol (EtOHE) as solvents, with the objective of evaluating its antioxidant effect on raw ground beef stored at 4 °C for 9 days. The analysis was carried out under the following treatments: CTL (meat without antioxidants), CIE (meat with infusion of epazote), CEtOHE (meat with ethanolic extract of epazote) and ASC (meat with sodium ascorbate solution). The characteristics ...

  18. Testing flight software on the ground: Introducing the hardware-in-the-loop simulation method to the Alpha Magnetic Spectrometer on the International Space Station

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Wenhao, E-mail: wenhao_sun@126.com [Southeast University, Nanjing 210096 (China); Cai, Xudong [Massachusetts Institute of Technology, MA 02139-4307 (United States); Meng, Qiao [Southeast University, Nanjing 210096 (China)

    2016-04-11

    Complex automatic protection functions are being added to the onboard software of the Alpha Magnetic Spectrometer. A hardware-in-the-loop simulation method has been introduced to overcome the difficulties of ground testing that are brought by hardware and environmental limitations. We invented a time-saving approach by reusing the flight data as the data source of the simulation system instead of mathematical models. This is easy to implement and it works efficiently. This paper presents the system framework, implementation details and some application examples.

  19. Comparison of radiometric scaling laws and detailed wave-optics simulations for designing ground-based laser satellite-illumination and receiver systems

    Science.gov (United States)

    Bush, Keith A.

    2002-12-01

    Ground-based optical transmitter and receiver systems designed for active imaging, active tracking and laser ranging of satellites in Earth orbit are very sensitive to physical conditions limiting the radiometric returns for achieving these measurements. The initial design of these systems is often based on simple radiometric scaling laws that provide estimates of average radiometric returns and are derived from experimental data or from more complex theoretical calculations. While these laws are quite useful, it is often easy to lose sight of the initial assumptions made in their formulation, and hence, the limits of their accuracy for designing certain systems. The objective of this paper is to review some of the commonly used radiometric scaling laws for active systems and to establish guidelines for their use based on comparisons of their predictions with results from detailed wave-optics simulations for different system design requirements and physical conditions. The combined effects of laser and transmitter beam parameters, wave-front aberrations, atmospheric turbulence, and satellite optical cross-section are considered.

  20. A ground-based radio frequency inductively coupled plasma apparatus for atomic oxygen simulation in low Earth orbit.

    Science.gov (United States)

    Huang, Yongxian; Tian, Xiubo; Yang, Shiqin; Chu, Paul K

    2007-10-01

    A radio frequency (rf) inductively coupled plasma apparatus has been developed to simulate the atomic oxygen environment encountered in low Earth orbit (LEO). Basing on the novel design, the apparatus can achieve stable, long lasting operation, pure and high density oxygen plasma beam. Furthermore, the effective atomic oxygen flux can be regulated. The equivalent effective atomic oxygen flux may reach (2.289-2.984) x 10(16) at.cm(2) s at an oxygen pressure of 1.5 Pa and rf power of 400 W. The equivalent atomic oxygen flux is about 100 times than that in the LEO environment. The mass loss measured from the polyimide sample changes linearly with the exposure time, while the density of the eroded holes becomes smaller. The erosion mechanism of the polymeric materials by atomic oxygen is complex and involves initial reactions at the gas-surface interface as well as steady-state material removal.

  1. Effects of large-scale wildfire on ground foraging ants (Hymenoptera: Formicidae) in southern California

    Science.gov (United States)

    Matsuda, Tritia; Turschak, Greta; Brehme, Cheryl; Rochester, Carlton; Mitrovich, Milan; Fisher, Robert

    2011-01-01

    We investigated the effect of broad-scale wildfire on ground foraging ants within southern California. In October and November of 2003, two wildfires burned large portions of the wildlands within San Diego County. Between January 2005 and September 2006, we surveyed 63 plots across four sites to measure the effect of the fires on the ant assemblages present in four vegetation types: 1) coastal sage scrub, 2) chaparral, 3) grassland, and 4) woodland riparian. Thirty-six of the 63 plots were sampled before the fires between March 2001 and June 2003. Mixed model regression analyses, accounting for the burn history of each plot and our pre- and postfire sampling efforts, revealed that fire had a negative effect on ant species diversity. Multivariate analyses showed that ant community structure varied significantly among the four vegetation types, and only the ant assemblage associated with coastal sage scrub exhibited a significant difference between burned and unburned samples. The most notable change detected at the individual species level involved Messor andrei (Mayr), which increased from ant samples to 32.1% in burned plots postfire. We theorize that M. andrei responded to the increase of bare ground and postfire seed production, leading to an increase in the detection rate for this species. Collectively, our results suggest that wildfires can have short-term impacts on the diversity and community structure of ground foraging ants in coastal sage scrub. We discuss these findings in relation to management implications and directions for future research.

  2. Simulating the thermal operating conditions in the thermal wells of ground-source heat-pump heat supply systems. Part I: Porous moisture freezing processes in soil

    Science.gov (United States)

    Vasilyev, G. P.; Peskov, N. V.; Lichman, V. A.; Gornov, V. F.; Kolesova, M. V.

    2015-08-01

    The mathematical models laid down in the new blocks of the INSOLAR.GSHP.12 software system simulating unsteady operating conditions of ground-source heat-pump (GSHP) heat supply systems are presented. The new model blocks take into account the effect the freezing of porous moisture in soil has on the GSHP system performance efficiency. Illustration is given to the need of taking into account the porous moisture freezing/thawing processes in soil, and the results from investigations devoted to the opening possibilities of constructing adaptive GSHP systems with controlled intensity of heat transfer in the soil-thermal well system are presented. The development of software simulating the porous moisture phase state variation processes in soil was preceded by development of mathematical equations representing the thermal conditions of soil body involving porous moisture freezing/thawing processes. A description of these equations is also given in the article. In constructing the mathematical model, the notion "effective thermal conductivity" of soil was introduced for taking into account the latent heat of phase transition that releases during the freezing of moisture. The above-mentioned effective thermal conductivity of soil involves two components: the soil thermal conductivity coefficient itself and an additional term modifying the thermal conductivity value for taking into account the influence of phase transition. For quantitatively evaluating the soil effective thermal conductivity component that takes into account the influence of phase transition, the soil freezing zone radius around the thermal well was determined. The obtained analytic solutions have been implemented in the form of computer program blocks, after which a "numerical experiment" was carried out for estimating the effect the porous moisture freezing/thawing processes have on the soil thermal conditions. It was demonstrated during that experiment that the soil thermal conductivities determined

  3. Cruising the rain forest floor: butterfly wing shape evolution and gliding in ground effect.

    Science.gov (United States)

    Cespedes, Ann; Penz, Carla M; DeVries, Philip J

    2015-05-01

    Flight is a key innovation in the evolutionary success of insects and essential to dispersal, territoriality, courtship and oviposition. Wing shape influences flight performance and selection likely acts to maximize performance for conducting essential behaviours that in turn results in the evolution of wing shape. As wing shape also contributes to fitness, optimal shapes for particular flight behaviours can be assessed with aerodynamic predictions and placed in an ecomorphological context. Butterflies in the tribe Haeterini (Nymphalidae) are conspicuous members of understorey faunas in lowland Neotropical forests. Field observations indicate that the five genera in this clade differ in flight height and behaviour: four use gliding flight at the forest floor level, and one utilizes flapping flight above the forest floor. Nonetheless, the association of ground level gliding flight behaviour and wing shape has never been investigated in this or any other butterfly group. We used landmark-based geometric morphometrics to test whether wing shapes in Haeterini and their close relatives reflected observed flight behaviours. Four genera of Haeterini and some distantly related Satyrinae showed significant correspondence between wing shape and theoretical expectations in performance trade-offs that we attribute to selection for gliding in ground effect. Forewing shape differed between sexes for all taxa, and male wing shapes were aerodynamically more efficient for gliding flight than corresponding females. This suggests selection acts differentially on male and female wing shapes, reinforcing the idea that sex-specific flight behaviours contribute to the evolution of sexual dimorphism. Our study indicates that wing shapes in Haeterini butterflies evolved in response to habitat-specific flight behaviours, namely gliding in ground effect along the forest floor, resulting in ecomorphological partitions of taxa in morphospace. The convergent flight behaviour and wing morphology

  4. Simulation of broad-band strong ground motion for a hypothetical Mw 7.1 earthquake on the Enriquillo Fault in Haiti

    Science.gov (United States)

    Douilly, Roby; Mavroeidis, George P.; Calais, Eric

    2017-10-01

    The devastating 2010 Mw 7.0 Haiti earthquake demonstrated the need to improve mitigation and preparedness for future seismic events in the region. Previous studies have shown that the earthquake did not occur on the Enriquillo Fault, the main plate boundary fault running through the heavily populated Port-au-Prince region, but on the nearby and previously unknown transpressional Léogâne Fault. Slip on that fault has increased stresses on the segment of Enriquillo Fault to the east of Léogâne, which terminates in the ˜3-million-inhabitant capital city of Port-au-Prince. In this study, we investigate ground shaking in the vicinity of Port-au-Prince, if a hypothetical rupture similar to the 2010 Haiti earthquake occurred on that segment of the Enriquillo Fault. We use a finite element method and assumptions on regional tectonic stress to simulate the low-frequency ground motion components using dynamic rupture propagation for a 52-km-long segment. We consider eight scenarios by varying parameters such as hypocentre location, initial shear stress and fault dip. The high-frequency ground motion components are simulated using the specific barrier model in the context of the stochastic modeling approach. The broad-band ground motion synthetics are subsequently obtained by combining the low-frequency components from the dynamic rupture simulation with the high-frequency components from the stochastic simulation using matched filtering at a crossover frequency of 1 Hz. Results show that rupture on a vertical Enriquillo Fault generates larger horizontal permanent displacements in Léogâne and Port-au-Prince than rupture on a south-dipping Enriquillo Fault. The mean horizontal peak ground acceleration (PGA), computed at several sites of interest throughout Port-au-Prince, has a value of ˜0.45 g, whereas the maximum horizontal PGA in Port-au-Prince is ˜0.60 g. Even though we only consider a limited number of rupture scenarios, our results suggest more intense ground

  5. Effect of simulated acid rain on vegetation

    Energy Technology Data Exchange (ETDEWEB)

    Ferenbaugh, R.W.

    1974-01-01

    Experiments were performed to determine the effects of simulated acid rain on Chenopodium quinoa, Hordeum vulgare and Phaseolus vulgaris. Detailed experiments were conducted only on Phaseolus vulgaris. Sulfuric acid solutions covering a pH range of 1.5 to 3.5 were used. Gross morphological effects noted at lower pH values included failure to attain normal height, necrosis and wrinkling of leaves, excessive and adventitious budding, and premature abscission of primary leaves. Histological effects included smaller cell size, a decreased amount of intercellular space, hypertrophied nuclei and nucleoli, and a reduction in the size of starch granules within the chloroplasts. Dry weight remained an approximately constant percentage of fresh weight, and chlorophyll analyses showed that both chlorophyll concentration and ratio of chlorophyll to chlorophyll also remained constant. Respirometer studies showed that respiration rate increased slightly and photosynthetic rate increased dramatically. Quantitative analyses indicated that carbohydrate content was reduced at low pH values. Root biomass was also reduced. Application of Congo red indicator solution to the acid treated tissue showed that it was being acidified to a pH of below 4. Experiments involving aspiration of control tissue in acid solutions suggest that the increase in photosynthetic rate and the decreases in carbohydrate content and root biomass were caused by an uncoupling of photophosphorylation of adenosine diphosphate. Uncoupling was probably caused by hydrogen ion interference with proton pumps associated with the electron transport chain in the light reactions of photosynthesis. 128 references. (MDF)

  6. Effects and implications of fault zone heterogeneity and anisotropy on earthquake strong ground motion

    Science.gov (United States)

    Su, Wei-Jou

    This thesis consists of two parts. Part one is concerned with the effect of fault zone heterogeneity on the strong ground motion of the Loma Preita earthquake. Part two is concerned with the effect of the effective hexagonal anisotropy of a fault zone on strong ground motion. A superposition of Gaussian beams is used to analyze these problems because it can account for both the rupture history of the fault plane and the fault zone heterogeneity. We also extend this method to investigate the combined effects of the rupture process on a fault plane and medium anisotropy on the synthetic seismograms. The strong ground motion of the Loma Prieta Earthquake is synthesized using a known three-dimensional crustal model of the region, a rupture model determined under the assumption of laterally homogeneous structure, and Green's functions computed by superposition of Gaussian beams. Compared to results obtained assuming a laterally homogeneous crust, stations lying to the northeast of the rupture zone are predicted to be defocused, while stations lying to the west of the fault trace are predicted to be focused. The defocusing is caused by a zone of high velocity material between the San Andreas and Sargent faults, and the focusing is caused by a region of low velocity lying between the Zayantes and San Andreas faults. If lateral homogeneity is assumed, the net effect of the predicted focusing and defocusing is to bias estimates of the relative slip of two high slip regions found in inversions of local and teleseismic body waves. These biases are similar in magnitude to those estimated for waveform inversions from the effects of using different subsets of data and/or different misfit functions and are similar in magnitude to the effects predicted for non-linear site responses.

  7. The effect of short ground vegetation on terrestrial laser scans at a local scale

    Science.gov (United States)

    Fan, Lei; Powrie, William; Smethurst, Joel; Atkinson, Peter M.; Einstein, Herbert

    2014-09-01

    Terrestrial laser scanning (TLS) can record a large amount of accurate topographical information with a high spatial accuracy over a relatively short period of time. These features suggest it is a useful tool for topographical survey and surface deformation detection. However, the use of TLS to survey a terrain surface is still challenging in the presence of dense ground vegetation. The bare ground surface may not be illuminated due to signal occlusion caused by vegetation. This paper investigates vegetation-induced elevation error in TLS surveys at a local scale and its spatial pattern. An open, relatively flat area vegetated with dense grass was surveyed repeatedly under several scan conditions. A total station was used to establish an accurate representation of the bare ground surface. Local-highest-point and local-lowest-point filters were applied to the point clouds acquired for deriving vegetation height and vegetation-induced elevation error, respectively. The effects of various factors (for example, vegetation height, edge effects, incidence angle, scan resolution and location) on the error caused by vegetation are discussed. The results are of use in the planning and interpretation of TLS surveys of vegetated areas.

  8. How flexibility and dynamic ground effect could improve bio-inspired propulsion

    Science.gov (United States)

    Quinn, Daniel

    2016-11-01

    Swimming animals use complex fin motions to reach remarkable levels of efficiency, maneuverability, and stealth. Propulsion systems inspired by these motions could usher in a new generation of advanced underwater vehicles. Two aspects of bio-inspired propulsion are discussed here: flexibility and near-boundary swimming. Experimental work on flexible propu