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Sample records for ground-surface pressure field

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

    Energy Technology Data Exchange (ETDEWEB)

    Massey, B.L.

    1981-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    ZHOU Xiao-jun; YANG Chang-yu

    2007-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Xu Bao-Qing

    2016-01-01

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

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

    Science.gov (United States)

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

    2016-04-01

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

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

    NARCIS (Netherlands)

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

    2016-01-01

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

  6. Monitoring ground-surface heating during expansion of the Casa Diablo production well field at Mammoth Lakes, California

    Science.gov (United States)

    Bergfeld, D.; Vaughan, R. Greg; Evans, William C.; Olsen, Eric

    2015-01-01

    The Long Valley hydrothermal system supports geothermal power production from 3 binary plants (Casa Diablo) near the town of Mammoth Lakes, California. Development and growth of thermal ground at sites west of Casa Diablo have created concerns over planned expansion of a new well field and the associated increases in geothermal fluid production. To ensure that all areas of ground heating are identified prior to new geothermal development, we obtained high-resolution aerial thermal infrared imagery across the region. The imagery covers the existing and proposed well fields and part of the town of Mammoth Lakes. Imagery results from a predawn flight on Oct. 9, 2014 readily identified the Shady Rest thermal area (SRST), one of two large areas of ground heating west of Casa Diablo, as well as other known thermal areas smaller in size. Maximum surface temperatures at 3 thermal areas were 26–28 °C. Numerous small areas with ground temperatures >16 °C were also identified and slated for field investigations in summer 2015. Some thermal anomalies in the town of Mammoth Lakes clearly reflect human activity.Previously established projects to monitor impacts from geothermal power production include yearly surveys of soil temperatures and diffuse CO2 emissions at SRST, and less regular surveys to collect samples from fumaroles and gas vents across the region. Soil temperatures at 20 cm depth at SRST are well correlated with diffuse CO2 flux, and both parameters show little variation during the 2011–14 field surveys. Maximum temperatures were between 55–67 °C and associated CO2 discharge was around 12–18 tonnes per day. The carbon isotope composition of CO2 is fairly uniform across the area ranging between –3.7 to –4.4 ‰. The gas composition of the Shady Rest fumarole however has varied with time, and H2S concentrations in the gas have been increasing since 2009.

  7. Prediction of ground surface displacement caused by grouting

    Institute of Scientific and Technical Information of China (English)

    郭风琪; 刘晓潭; 童无期; 单智

    2015-01-01

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

  8. Casimir light: field pressure.

    OpenAIRE

    1994-01-01

    The electromagnetic field is assigned a self-consistent role in which abrupt slowing of the collapse produces radiation and the pressure of the radiation produces abrupt slowing. A simple expression is introduced for the photon spectrum. Conditions for light emission are proposed that imply a high degree of spatial localization. Some numerical checks are satisfied. A study of the mechanical equations of motion suggests an explanation of the very short time scale in terms of oppositely directe...

  9. Effects of Jet Pressure on the Ground Surface Quality and CBN Wheel Wear in Grinding AISI 690 Nickel-Based Superalloy

    Science.gov (United States)

    Guitouni, Ahmed; Chaieb, Iheb; Rhouma, Amir Ben; Fredj, Nabil Ben

    2016-09-01

    Fluid application in grinding is getting attention as higher stock removal rates, higher surface integrity and longer wheel life are required. It is necessary to define proper conditions of application for meeting high productivity goals by lowering the specific grinding energy and reducing the temperature of the contact zone. The present study investigated the capacity of the jet pressure of a spot nozzle to improve the wear of a CBN wheel when grinding the AISI 690 superalloy. Grinding experiments were conducted with an emulsion-type cooling fluid delivered at pressure ranging from 0.1 to 4 MPa. Results show that the maximum stock removal, reached at 4 MPa, is 5 times the stock removal obtained at 0.1 MPa, while the grinding ratio at 4 MPa is 8 times that at 0.1 MPa, and there is a critical pressure (P c) around 1.5 MPa corresponding to the minimum specific grinding energy. Scanning electron microscopy of the grain tips showed that the wear mechanism shifts from breaking and dislodgment at low jet pressure to micro-fracture resulting in continuous self-sharpening of the abrasive grains. By lubricating at jet pressure close to P c, there is less thermal damage due to plowing and sliding and the resulting lower loading of the abrasive grains favors the micro-fracture of grains and thus a longer wheel life.

  10. Effects of Jet Pressure on the Ground Surface Quality and CBN Wheel Wear in Grinding AISI 690 Nickel-Based Superalloy

    Science.gov (United States)

    Guitouni, Ahmed; Chaieb, Iheb; Rhouma, Amir Ben; Fredj, Nabil Ben

    2016-11-01

    Fluid application in grinding is getting attention as higher stock removal rates, higher surface integrity and longer wheel life are required. It is necessary to define proper conditions of application for meeting high productivity goals by lowering the specific grinding energy and reducing the temperature of the contact zone. The present study investigated the capacity of the jet pressure of a spot nozzle to improve the wear of a CBN wheel when grinding the AISI 690 superalloy. Grinding experiments were conducted with an emulsion-type cooling fluid delivered at pressure ranging from 0.1 to 4 MPa. Results show that the maximum stock removal, reached at 4 MPa, is 5 times the stock removal obtained at 0.1 MPa, while the grinding ratio at 4 MPa is 8 times that at 0.1 MPa, and there is a critical pressure ( P c) around 1.5 MPa corresponding to the minimum specific grinding energy. Scanning electron microscopy of the grain tips showed that the wear mechanism shifts from breaking and dislodgment at low jet pressure to micro-fracture resulting in continuous self-sharpening of the abrasive grains. By lubricating at jet pressure close to P c, there is less thermal damage due to plowing and sliding and the resulting lower loading of the abrasive grains favors the micro-fracture of grains and thus a longer wheel life.

  11. Simulation Analysis on Power Frequency Electric Field at Ground Surface Near EHV Power Transmission Tower%超高压输电线路铁塔附近地面工频电场仿真分析

    Institute of Scientific and Technical Information of China (English)

    李永明; 范与舟; 徐禄文

    2013-01-01

    根据铁塔实际结构和导线抛物线方程,建立了铁塔附近三维电场计算模型.基于模拟电荷法分析了500 kV输电线路铁塔周围地面上的工频电场分布,分析了铁塔对其附近电场环境的影响,并讨论了影响电场计算结果的因素.研究结果表明:铁塔对其附近地面电场有一定屏蔽作用,电场强度在铁塔下方显著降低且在金属构架处产生畸变;铁塔的影响范围和铁塔高度及塔基尺寸有关;铁塔构架等效半径、线单元剖分段数以及铁塔不同简化模型都会影响计算结果.%Based on actual structure of power transmission tower and parabolic equation of transmission lines,a three-dimensional model to compute power frequency electric field at ground surface near transmission tower is built.According to charge simulation method,the distribution of power frequency electric field at ground surface near 500kV transmission tower as well as the impacts of transmission tower on nearby electric field is analyzed,and the factors impacting computational results of electric field are discussed.Research results show that there is a certain screening effect of transmission tower on ground surface electric field nearby the tower,so the electric field intensity beneath the tower decreases obviously and electric field distortion appears at the positions where metal frameworks are erected.The impacting area is related to the height of the tower and the size of tower foundation; computational result of electric field will be impacted by the equivalent radius of tower framework,the number of line segments and different simplified models of the tower.

  12. Transport of Bacteria and Virus-Sized Particles and Bacteriophage from Ground Surface to Depth in a Bedrock Aquifer - A Field Experiment

    Science.gov (United States)

    Novakowski, K. S.; Trimper, S.; Praamsma, T.; Springthorpe, S.

    2010-12-01

    Shallow, unprotected bedrock aquifers are common sources of drinking water supply in eastern North America. The vulnerability of these aquifers to contamination from pathogens is widely recognised, although little is actually known about the transport processes involved, particularly where the source is located near to or on ground surface (i.e. a septic system). In this experiment we explore the transport of fluorescent microspheres having diameters of 1.75 and 0.3 µm and the bacteriophage Φ-X174 in a sparsely-fractured gneissic terrain having minimal overburden cover. The experiment was conducted by ponding water in a 7 m2 area on the edge of an outcrop having observable vertical fractures and measuring the arrival of particles in two nearby monitoring wells. A conservative solute tracer (Lissamine FF) was also used to follow the solute front. In order to encourage transport to the wells and to provide a discharge stream to sample, pumping was conducted at a rate of 7.7 L/min from the lower half of the 15-m deep well farthest from the pond (approximately 7 m away). Sampling was conducted from the pumping stream, the upper 5 m of that well and the upper 5 m of an additional well located about 5 m from the surface pond. The experiment was conducted over a 48 hr period and samples were obtained every 15 min initially declining to once every 2 hrs towards the end of the experiment. Analysis of the bacteriophage was conducted using the Double Agar Layer method and the concentration of microspheres was determined using epi-fluorescent microscopy. As the latter is very time consuming, only preliminary results are available for the microsphere transport. The results show widespread migration of both the microspheres and the bacteriophage, as arrival in all sampling locations was detected. Mass recovery was low but similar for both the bacteriophage and the solute tracer, although the majority of the bacteriophage arrived much earlier than the majority of the solute

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

    Directory of Open Access Journals (Sweden)

    T. Chiba

    2016-06-01

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

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

    Science.gov (United States)

    Chiba, T.; Hasi, B.

    2016-06-01

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

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

    Science.gov (United States)

    Kempka, Thomas; Tillner, Elena

    2015-04-01

    are decreased by almost 10 %. Furthermore, if the vertical location of the open well section is directly located below the caprock, vertical displacements at the ground surface are significantly higher compared to a lower open hole position. Consequently, a focus in site characterisation in the scope of geological underground utilisation should be on detailed assessment of caprock permeability. These data may be derived by well logs and hydraulic tests as well as laboratory tests on core samples. Kempka, T., Nielsen, C.M., Frykman, P., Shi, J.-Q., Bacci, G., Dalhoff, F. Coupled Hydro-Mechanical Simulations of CO2 Storage Supported by Pressure Management Demonstrate Synergy Benefits from Simultaneous Formation Fluid Extraction (2014) Oil Gas Sci Technol, doi:10.2516/ogst/2014029. Klimkowski, Ł., Nagy, S., Papiernik, B., Orlic, B., Kempka, T. Numerical simulations of enhanced gas recovery at the Załęcze gas field in Poland confirm high storage capacities and mechanical integrity (2015) Oil Gas Sci Technol (accepted). Tillner, E., Shi, J-.Q., Bacci, G., Nielsen, C.M., Frykman, P., Dalhoff, F., Kempka, T. Coupled Dynamic Flow and Geomechanical Simulations for an Integrated Assessment of CO2 Storage Impacts in a Saline Aquifer (2014) Energy Procedia, 63:2879-2893, doi:10.1016/j.egypro.2014.11.311.

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

    Science.gov (United States)

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

    2016-04-01

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

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

    Science.gov (United States)

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

    2011-12-01

    observed InSAR data. We find that although the preferred parameter estimate has relatively poor resolution, the resolution that is afforded demonstrates plausible agreement with parameters determined from well tests. Our method implies a more conductive fault zone than field tests, which could be due to either 1) unmodeled three-dimensional flow or 2) each method being sensitive to an effective conductivity that is scale dependent. Unmodeled three-dimensional flow (e.g., fault parallel flow) will make the fault zone appear less conductive; we therefore consider our estimate to be a minimum. It could be that ground surface deformations due to fault zone diffusion are sensitive to structures over a longer length scale than well tests. We hypothesize that the apparently large values of hydraulic conductivity result from parameter estimation at a larger scale than that of well tests. This hypothesis is similar to the observation by Evans et al. (1997) that smaller-scale fault zone permeability measurements result in lower bound estimates.

  18. The pressure field of imploding lightbulbs

    Science.gov (United States)

    Czechanowski, M.; Ikeda, C.; Duncan, J. H.

    2015-03-01

    The implosion of A19 incandescent lightbulbs in a high-pressure water environment is studied in a 1.77-m-diameter steel tank. Underwater blast sensors are used to measure the dynamic pressure field near the lightbulbs and the implosions are photographed with a high-speed movie camera at a frame rate of 24,000 pps. The movie camera and the pressure signal recording system are synchronized to enable correlation of features in the movie frames with those in the pressure records. It is found that the gross dimensions and weight of the bulbs are very similar from one bulb to another, but the ambient water pressure at which a given bulb implodes (, called the implosion pressure) varies from 6.29 to 11.98 atmospheres, probably due to inconsistencies in the glass wall thickness and perhaps other detailed characteristics of the bulbs. The dynamic pressures (the local pressure minus , as measured by the sensors) first drop during the implosion and then reach a strong positive peak at about the time that the bulb reaches minimum volume. The peak dynamic pressure varies from 3.61 to 28.66 atmospheres. In order to explore the physics of the implosion process, the dynamic pressure signals are compared to calculations of the pressure field generated by the collapse of a spherical bubble in a weakly compressible liquid. The wide range of implosion pressures is used in combination with the calculations to explore the effect of the relative liquid compressibility and the bulb itself on the dynamic pressure field.

  19. Field mapping of ballistic pressure pulse sources

    Directory of Open Access Journals (Sweden)

    Rad Abtin Jamshidi

    2015-09-01

    Full Text Available Ballistic pressure pulse sources are used since late 1990s for the extracorporeal treatment of chronic Enthesitis. Newly indications are found in trigger-point-therapy for the treatment of musculoskeletal disorders. In both applications excellent results without relevant side effects were found in clinical trials. The technical principle of pressure pulse source is based on the same techniques used in air guns. A projectile is accelerated by pressurized air and hits the applicator with high kinetic energy. By this a compression wave travels through the material and induces a fast (4..5μs, almost singular pressure pulse of 2..10 MPa, which is followed by an equally short rarefaction phase of about the same amplitude. It is assumed that the pressure pulse accounts for the biomedical effects of the device. The slower inertial motion of the waveguide is damped by elastic stoppers, but still can be measured several micro seconds after the initial pressure pulse. In order to characterize the pressure pulse devices, field mapping is performed on several radial pressure pulse sources using the fiber optic hydrophone and a polyvinylidenfluorid (PVDF piezoelectric hydrophone. It could be shown that the current standard (IEC 61846 is not appropriate for characterization of ballistic pressure pulse sources.

  20. Pressure, Chaotic Magnetic Fields and MHD Equilibria

    Energy Technology Data Exchange (ETDEWEB)

    S.R. Hudson & N. Nakajima

    2010-05-12

    Analyzes of plasma behavior often begin with a description of the ideal magnetohydrodynamic equilibrium, this being the simplest model capable of approximating macroscopic force balance. Ideal force balance is when the pressure gradient is supported by the Lorentz force, ∇p = j x B. We discuss the implications of allowing for a chaotic magnetic field on the solutions to this equation. We argue that the solutions are pathological and not suitable for numerical calculations. If the pressure and magnetic Field are continuous, the only non-trivial solutions have an uncountable infinity of discontinuities in the pressure gradient and current. The problems arise from the arbitrarily small length scales in the structure of the field, and the consequence of ideal force balance that the pressure is constant along the Field-lines, B • ∇p = 0. A simple method to ameliorate the singularities is to include a small but Finite perpendicular diffusion. A self-consistent set of equilibrium equations is described and some algorithmic approaches aimed at solving these equations are discussed.

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

    Science.gov (United States)

    Leaf, Julian S.; Erell, Evyatar

    2017-07-01

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

  2. Power productivity of the ground surface

    Directory of Open Access Journals (Sweden)

    Gutu A.I.

    2008-12-01

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

  3. Passive heating of the ground surface

    Science.gov (United States)

    Tyburczyk, Anna

    2016-03-01

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

  4. Passive heating of the ground surface

    Directory of Open Access Journals (Sweden)

    Tyburczyk Anna

    2016-01-01

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

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

    Science.gov (United States)

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

    2016-12-01

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

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

    Directory of Open Access Journals (Sweden)

    V. V. Guskov

    2017-01-01

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

  7. Side abutment pressure distribution by field measurement

    Institute of Scientific and Technical Information of China (English)

    WANG Lian-guo; SONG Yang; HE Xing-hua; ZHANG Jian

    2008-01-01

    Given the 7123 working face in the Qidong Coal Mine of the Wanbei Mining Group, nine dynamic roof monitors were installed in the crossheading to measure the amount and velocity of roof convergence in different positions and at different times and three steel bored stress sensors were installed in the return airway to measure rock stress at depth. On the basis of this arrangement, the rule of change of the distribution of the side abutment pressure with the advance of the working face and movement of overlying strata was studied. The rule of change and the stability of rock stress at depth were measured. Secondly, the affected area and stability time of the side abutment pressure were also studied. The results show that: 1) During working, the face advanced distance was from 157 m to 99 m, the process was not effected by mining induced pressure. When the distance was 82 m, the position of peak stress was 5 m away from the coal wall. When the distance was 37 m, the position of peak stress away from the coal wall was about 15 m to 20 m and finally reached a steady state; 2) the time and the range of the peak of side rock pressure obtained from stress sensors were consistent with the results from the dynamic roof monitors; 3) the position of the peak pressure was 25 m away from the coal wall.

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

    Science.gov (United States)

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

    2008-01-01

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

  9. Temperature field simulation of gob influenced by atmospheric pressure

    Institute of Scientific and Technical Information of China (English)

    王刚; 罗海珠; 梁运涛; 王继仁

    2015-01-01

    The current temperature field model of mine gob does not take the boundary conditions of the atmospheric pressure into account, while the actual atmospheric pressure is influenced by weather, so as to produce differences between ventilation negative pressure of the working face and the negative pressure of gas drainage in gob, thus interfering the calculated results of gob temperature field. According to the characteristics of the actual air flow and temperature change in gob, a two-dimensional temperature field model of the gob was built, and the relational model between the air pressure of intake and outlet of the gob and the atmospheric pressure was established, which was introduced into the boundary conditions of temperature field to conduct calculation. By means of analysis on the simulation example, and comparison with the traditional model, the results indicate that atmospheric pressure change had notable impact on the distribution of gob temperature field. The laboratory test system of gob temperature field was constructed, and the relative error between simulated and measured value was no greater than 9.6%, which verified the effectiveness of the proposed model. This work offers theoretical basis for accurate calculation of temperature and prediction of ignition source in mine gob, and has important implications on preventing spontaneous combustion of coal.

  10. Design principles for high-pressure force fields: Aqueous TMAO solutions from ambient to kilobar pressures

    Science.gov (United States)

    Hölzl, Christoph; Kibies, Patrick; Imoto, Sho; Frach, Roland; Suladze, Saba; Winter, Roland; Marx, Dominik; Horinek, Dominik; Kast, Stefan M.

    2016-04-01

    Accurate force fields are one of the major pillars on which successful molecular dynamics simulations of complex biomolecular processes rest. They have been optimized for ambient conditions, whereas high-pressure simulations become increasingly important in pressure perturbation studies, using pressure as an independent thermodynamic variable. Here, we explore the design of non-polarizable force fields tailored to work well in the realm of kilobar pressures - while avoiding complete reparameterization. Our key is to first compute the pressure-induced electronic and structural response of a solute by combining an integral equation approach to include pressure effects on solvent structure with a quantum-chemical treatment of the solute within the embedded cluster reference interaction site model (EC-RISM) framework. Next, the solute's response to compression is taken into account by introducing pressure-dependence into selected parameters of a well-established force field. In our proof-of-principle study, the full machinery is applied to N,N,N-trimethylamine-N-oxide (TMAO) in water being a potent osmolyte that counteracts pressure denaturation. EC-RISM theory is shown to describe well the charge redistribution upon compression of TMAO(aq) to 10 kbar, which is then embodied in force field molecular dynamics by pressure-dependent partial charges. The performance of the high pressure force field is assessed by comparing to experimental and ab initio molecular dynamics data. Beyond its broad usefulness for designing non-polarizable force fields for extreme thermodynamic conditions, a good description of the pressure-response of solutions is highly recommended when constructing and validating polarizable force fields.

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

    Directory of Open Access Journals (Sweden)

    Akihiro Takeuchi

    2012-01-01

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

  12. Comparison of unsteady pressure fields on turrets with different surface features using pressure-sensitive paint

    Science.gov (United States)

    Gordeyev, Stanislav; De Lucca, Nicholas; Jumper, Eric J.; Hird, Kyle; Juliano, Thomas J.; Gregory, James W.; Thordahl, James; Wittich, Donald J.

    2014-01-01

    Spatially temporally resolved unsteady pressure fields on a surface of a hemisphere-on-cylinder turret with either a flat or a conformal window with realistic features such as gaps and "smile" cutouts were characterized using fast-response pressure-sensitive paint at M = 0.33 for several window viewing angles. Various statistical properties of pressure fields were computed, and geometry effects on the unsteady pressure fields were analyzed and discussed. Proper orthogonal decomposition was also used to extract dominant pressure modes and corresponding temporal coefficients and to analyze and compare instantaneous pressure structures for different turret geometric features and the window viewing angles. An unsteady separation off the turret and a recirculation region downstream of the turret were identified as dominant sources of the unsteady pressure. It was found that while all geometric features affected the unsteady pressure field, the "smiles," positioned spanwise-symmetrically on both sides of the turret, were the leading cause of these changes, followed by the looking forward flat window. The gaps, the side- and the back-looking flat window introduced only small local changes.

  13. Pressure calculation in hybrid particle-field simulations.

    Science.gov (United States)

    Milano, Giuseppe; Kawakatsu, Toshihiro

    2010-12-07

    In the framework of a recently developed scheme for a hybrid particle-field simulation techniques where self-consistent field (SCF) theory and particle models (molecular dynamics) are combined [J. Chem. Phys. 130, 214106 (2009)], we developed a general formulation for the calculation of instantaneous pressure and stress tensor. The expressions have been derived from statistical mechanical definition of the pressure starting from the expression for the free energy functional in the SCF theory. An implementation of the derived formulation suitable for hybrid particle-field molecular dynamics-self-consistent field simulations is described. A series of test simulations on model systems are reported comparing the calculated pressure with those obtained from standard molecular dynamics simulations based on pair potentials.

  14. Pressure sensing by flexible, organic, field effect transistors

    Science.gov (United States)

    Manunza, I.; Sulis, A.; Bonfiglio, A.

    2006-10-01

    A mechanical sensor based on a pentacene field effect transistor has been fabricated. The pressure dependence of the output current has been investigated by applying a mechanical stimulus by means of a pressurized air flow. Experimental results show a reversible current dependence on pressure. Data analysis suggests that variations of threshold voltage, mobility and contact resistance are responsible for current variations. Thanks to the flexibility of the substrate and the low cost of the technology, this device opens the way for flexible mechanical sensors that can be used in a variety of innovative applications such as e-textiles and robotic interfaces.

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

    Science.gov (United States)

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

    2015-12-01

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

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

    Institute of Scientific and Technical Information of China (English)

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

    2007-01-01

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

  17. Assessment of pressure field calculations from particle image velocimetry measurements

    Science.gov (United States)

    Charonko, John J.; King, Cameron V.; Smith, Barton L.; Vlachos, Pavlos P.

    2010-10-01

    This paper explores the challenges associated with the determination of in-field pressure from DPIV (digital particle image velocimetry)-measured planar velocity fields for time-dependent incompressible flows. Several methods that have been previously explored in the literature are compared, including direct integration of the pressure gradients and solution of different forms of the pressure Poisson equations. Their dependence on grid resolution, sampling rate, velocity measurement error levels and off-axis recording was quantified using artificial data of two ideal sample flow fields—a decaying vortex flow and pulsatile flow between two parallel plates, and real DPIV and pressure data from oscillating flow through a diffuser. The need for special attention to mitigate the velocity error propagation in the pressure estimation is also addressed using a physics-preserving approach based on proper orthogonal decomposition (POD). The results demonstrate that there is no unique or optimum method for estimating the pressure field and the resulting error will depend highly on the type of the flow. However, the virtual boundary, omni-directional pressure integration scheme first proposed by Liu and Katz (2006 Exp. Fluids 41 227-40) performed consistently well in both synthetic and experimental flows. Estimated errors can vary from less than 1% to over 100% with respect to the expected value, though in contrast to more traditional smoothing algorithms, the newly proposed POD-based filtering approach can reduce errors for a given set of conditions by an order of magnitude or more. This analysis offers valuable insight that allows optimizing the choice of methods and parameters based on the flow under consideration.

  18. Fractal analysis of pressure transients in the Geysers Geothermal Field

    Energy Technology Data Exchange (ETDEWEB)

    Acuna, J.A.; Ershaghi, I.; Yortsos, Y.C.

    1992-01-01

    The conventionally accepted models for the interpretation of pressure transient tests in naturally fractured reservoirs usually involve simplistic assumptions regarding the geometry and transport properties of the fractured medium. Many single well tests in this type of reservoirs fail to show the predicted behavior for dual or triple porosity or permeability systems and cannot be explained by these models. This paper describes the application of a new model based on a fractal interpretation of the fractured medium. The approach, discussed elsewhere [2], [6], is applied to field data from The Geysers Geothermal Field. The objective is to present an alternative interpretation to well tests that characterizes the fractured medium in a manner more consistent with other field evidence. The novel insight gained from fractal geometry allows the identification of important characteristics of the fracture structure that feeds a particular well. Some simple models are also presented that match the field transient results.

  19. Simulations of pressure and salinity fields at Aespoe

    Energy Technology Data Exchange (ETDEWEB)

    Loefman, J. [VTT Energy, Espoo (Finland)

    1997-04-01

    The primary objective of this study was to examine whether the geochemical field data from Aespoe could be interpreted and understood by means of numerical simulations for flow and transport. A site-specific simulation model for groundwater flow and salt transport was developed on the basis of the field investigations. Both steady-state and transient simulations of flow and transport were performed. In the transient simulations, land uplift and the effect of diffusion into/from the matrix blocks with stagnant water were taken into account. The computational results were evaluated on the basis of the experimental values for the pressure and salt concentration.

  20. Simulations of nonlinear continuous wave pressure fields in FOCUS

    Science.gov (United States)

    Zhao, Xiaofeng; Hamilton, Mark F.; McGough, Robert J.

    2017-03-01

    The Khokhlov - Zabolotskaya - Kuznetsov (KZK) equation is a parabolic approximation to the Westervelt equation that models the effects of diffraction, attenuation, and nonlinearity. Although the KZK equation is only valid in the far field of the paraxial region for mildly focused or unfocused transducers, the KZK equation is widely applied in medical ultrasound simulations. For a continuous wave input, the KZK equation is effectively modeled by the Bergen Code [J. Berntsen, Numerical Calculations of Finite Amplitude Sound Beams, in M. F. Hamilton and D. T. Blackstock, editors, Frontiers of Nonlinear Acoustics: Proceedings of 12th ISNA, Elsevier, 1990], which is a finite difference model that utilizes operator splitting. Similar C++ routines have been developed for FOCUS, the `Fast Object-Oriented C++ Ultrasound Simulator' (http://www.egr.msu.edu/˜fultras-web) to calculate nonlinear pressure fields generated by axisymmetric flat circular and spherically focused ultrasound transducers. This new routine complements an existing FOCUS program that models nonlinear ultrasound propagation with the angular spectrum approach [P. T. Christopher and K. J. Parker, J. Acoust. Soc. Am. 90, 488-499 (1991)]. Results obtained from these two nonlinear ultrasound simulation approaches are evaluated and compared for continuous wave linear simulations. The simulation results match closely in the farfield of the paraxial region, but the results differ in the nearfield. The nonlinear pressure field generated by a spherically focused transducer with a peak surface pressure of 0.2MPa radiating in a lossy medium with β = 3.5 is simulated, and the computation times are also evaluated. The nonlinear simulation results demonstrate acceptable agreement in the focal zone. These two related nonlinear simulation approaches are now included with FOCUS to enable convenient simulations of nonlinear pressure fields on desktop and laptop computers.

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

    Science.gov (United States)

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

    2013-12-01

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

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

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

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

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

    CERN Document Server

    Rychkov, Igor

    2012-01-01

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

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

    OpenAIRE

    Hartmann, Andreas; Rath, Volker

    2008-01-01

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

  5. Sound field separation with sound pressure and particle velocity measurements

    DEFF Research Database (Denmark)

    Fernandez Grande, Efren; Jacobsen, Finn; Leclère, Quentin

    2012-01-01

    separation techniques make it possible to distinguish between outgoing and incoming waves from the two sides, and thus NAH can be applied. In this paper, a separation method based on the measurement of the particle velocity in two layers and another method based on the measurement of the pressure...... and the velocity in a single layer are proposed. The two methods use an equivalent source formulation with separate transfer matrices for the outgoing and incoming waves, so that the sound from the two sides of the array can be modeled independently. A weighting scheme is proposed to account for the distance...... pressure-velocity method, although it requires an additional measurement surface. On the whole, the separation methods can be useful when the disturbance of the incoming field is significant. Otherwise the direct reconstruction is more accurate and straightforward. © 2012 Acoustical Society of America....

  6. Low-Pressure, Field-Ionizing Mass Spectrometer

    Science.gov (United States)

    Hartley, Frank; Smith, Steven

    2009-01-01

    A small mass spectrometer utilizing a miniature field ionization source is now undergoing development. It is designed for use in a variety of applications in which there are requirements for a lightweight, low-power-consumption instrument that can analyze the masses of a wide variety of molecules and ions. The device can operate without need for a high-vacuum, carrier-gas feed radioactive ionizing source, or thermal ionizer. This mass spectrometer can operate either in the natural vacuum of outer space or on Earth at any ambient pressure below 50 torr (below about 6.7 kPa) - a partial vacuum that can easily be reached by use of a small sampling pump. This mass spectrometer also has a large dynamic range - from singly charged small gas ions to deoxyribonucleic acid (DNA) fragments larger than 104 atomic mass units - with sensitivity adequate for detecting some molecules and ions at relative abundances of less than one part per billion. This instrument (see figure) includes a field ionizer integrated with a rotating-field mass spectrometer (RFMS). The field ionizer effects ionization of a type characterized as "soft" in the art because it does not fragment molecules or initiate avalanche arcing. What makes the "soft" ionization mode possible is that the distance between the ionizing electrodes is less than mean free path for ions at the maximum anticipated operating pressure, so that the ionizer always operates on the non-breakdown side of the applicable Paschen curve (a standard plot of breakdown potential on the ordinate and pressure electrode separation on the abscissa). The field ionizer in this instrument is fabricated by micromachining a submicron-thick membrane out of an electrically nonconductive substrate, coating the membrane on both sides to form electrodes, then micromachining small holes through the electrodes and membrane. Because of the submicron electrode separation, even a potential of only 1 V applied between the electrodes gives rise to an electric

  7. Error Propagation Dynamics of PIV-based Pressure Field Calculations: How well does the pressure Poisson solver perform inherently?

    Science.gov (United States)

    Pan, Zhao; Whitehead, Jared; Thomson, Scott; Truscott, Tadd

    2016-08-01

    Obtaining pressure field data from particle image velocimetry (PIV) is an attractive technique in fluid dynamics due to its noninvasive nature. The application of this technique generally involves integrating the pressure gradient or solving the pressure Poisson equation using a velocity field measured with PIV. However, very little research has been done to investigate the dynamics of error propagation from PIV-based velocity measurements to the pressure field calculation. Rather than measure the error through experiment, we investigate the dynamics of the error propagation by examining the Poisson equation directly. We analytically quantify the error bound in the pressure field, and are able to illustrate the mathematical roots of why and how the Poisson equation based pressure calculation propagates error from the PIV data. The results show that the error depends on the shape and type of boundary conditions, the dimensions of the flow domain, and the flow type.

  8. Error Propagation Dynamics of PIV-based Pressure Field Calculations: How well does the pressure Poisson solver perform inherently?

    CERN Document Server

    Pan, Zhao; Thomson, Scott; Truscott, Tadd

    2016-01-01

    Obtaining pressure field data from particle image velocimetry (PIV) is an attractive technique in fluid dynamics due to its noninvasive nature. The application of this technique generally involves integrating the pressure gradient or solving the pressure Poisson equation using a velocity field measured with PIV. However, very little research has been done to investigate the dynamics of error propagation from PIV-based velocity measurements to the pressure field calculation. Rather than measure the error through experiment, we investigate the dynamics of the error propagation by examining the Poisson equation directly. We analytically quantify the error bound in the pressure field, and are able to illustrate the mathematical roots of why and how the Poisson equation based pressure calculation propagates error from the PIV data. The results show that the error depends on the shape and type of boundary conditions, the dimensions of the flow domain, and the flow type.

  9. Error propagation dynamics of PIV-based pressure field calculations: How well does the pressure Poisson solver perform inherently?

    Science.gov (United States)

    Pan, Zhao; Whitehead, Jared; Thomson, Scott; Truscott, Tadd

    2016-08-01

    Obtaining pressure field data from particle image velocimetry (PIV) is an attractive technique in fluid dynamics due to its noninvasive nature. The application of this technique generally involves integrating the pressure gradient or solving the pressure Poisson equation using a velocity field measured with PIV. However, very little research has been done to investigate the dynamics of error propagation from PIV-based velocity measurements to the pressure field calculation. Rather than measure the error through experiment, we investigate the dynamics of the error propagation by examining the Poisson equation directly. We analytically quantify the error bound in the pressure field, and are able to illustrate the mathematical roots of why and how the Poisson equation based pressure calculation propagates error from the PIV data. The results show that the error depends on the shape and type of boundary conditions, the dimensions of the flow domain, and the flow type.

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

    Science.gov (United States)

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

    2015-08-01

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

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

    Science.gov (United States)

    Nakano, K.; Chikatsu, H.

    2015-05-01

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

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

    Directory of Open Access Journals (Sweden)

    K. Nakano

    2015-05-01

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

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

    Science.gov (United States)

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

    2007-12-01

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

  14. Vacuum energy density and pressure of a massive scalar field

    Science.gov (United States)

    Mera, Fernando Daniel; Fulling, S. A.

    2015-06-01

    With a view toward application of the Pauli-Villars regularization method to the Casimir energy of boundaries, we calculate the expectation values of the components of the stress tensor of a confined massive field in 1+1 space-time dimensions. Previous papers by Hays and Fulling are bridged and generalized. The Green function for the time-independent Schrödinger equation is constructed from the Green function for the whole line by the method of images; equivalently, the one-dimensional system is solved exactly in terms of closed classical paths and periodic orbits. Terms in the energy density and in the eigenvalue density attributable to the two boundaries individually and those attributable to the confinement of the field to a finite interval are distinguished so that their physical origins are clear. Then the pressure is found similarly from the cylinder kernel, the Green function associated most directly with an exponential frequency cutoff of the Fourier mode expansion. Finally, we discuss how the theory could be rendered finite by the Pauli-Villars method.

  15. Vacuum energy density and pressure of a massive scalar field

    CERN Document Server

    Mera, Fernando Daniel

    2014-01-01

    With a view toward application of the Pauli-Villars regularization method to the Casimir energy of boundaries, we calculate the expectation values of the components of the stress tensor of a confined massive field in 1+1 space-time dimensions. Previous papers by Hays and Fulling are bridged and generalized. The Green function for the time-independent Schrodinger equation is constructed from the Green function for the whole line by the method of images; equivalently, the one-dimensional system is solved exactly in terms of closed classical paths and periodic orbits. Terms in the energy density and in the eigenvalue density attributable to the two boundaries individually and those attributable to the confinement of the field to a finite interval are distinguished so that their physical origins are clear. Then the pressure is found similarly from the cylinder kernel, the Green function associated most directly with an exponential frequency cutoff of the Fourier mode expansion. Finally, we discuss how the theory ...

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

    Institute of Scientific and Technical Information of China (English)

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

    2006-01-01

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

  17. Evaluation on Uncertainty of Measurement Result of Pressure Transmitter Field Verification

    Institute of Scientific and Technical Information of China (English)

    CHEN; Ping

    2015-01-01

    Calibration data of pressure instrument,pressure transmitter and pressure measurement control system with field pressure calibrator on the site of production and work can represent actual situation of the production and work,reduce and avoid the error on account of the difference of

  18. 交流线路与+800 kV直流线路同走廊时的地面混合电场研究%Study on the Hybrid Electric Field Over the Ground Surface Under AC Lines and ±800 kV DC Lines in the Same Corridor

    Institute of Scientific and Technical Information of China (English)

    杨勇; 陆家榆; 鞠勇

    2009-01-01

    交流线路与±800 kV直流线路共用走廊的情况将在我困出现,因此需要研究该种线路地面混合电场的计算方法,以满足工程设计和环境保护需要.在分析同走廊架设的交流线路与±800 kV直流线路相互影响的基础上,提出了一种计算该类线路地面混合电场的方法.通过对比使用该方法得到的计算结果与不考虑两种线路相互影响时的计算结果,得到如下结论:相对于忽略交直流线路的相互影响,当考虑其相互影响时,在同走廊交直流线路中心附近,地面混合电场的瞬时最大值横向分布有波动;两种计算方法得到的地面混合电场有效值分布曲线基本重合;在一个交流周期内,同走廊线路地面混合电场的最大值与单独±800 kV直流线路地面合成电场的最大值差别很小.%Parallel adjacent erection of AC transmission lines and ±800 kV DC transmission lines in the same corridor will occur in China, so the calculation method for the hybrid electric field over the ground under this type of lines should be studied so as to satisfy the requirements of engineering design and environmental protection. Based on the analysis of mutual influences between AC transmission lines and ±800 kV DC transmission lines in the same corridor, a calculation method is proposed. Through the comparison between the calculation results achieved with this method and the corresponding calculation results obtained when the mutual influences between AC transmission lines and ±800 kV DC transmission lines are neglected, some conclusions can be drawn as follows: compared with the calculation results obtained when the mutual influences are neglected, near the center of AC transmission lines and ±800 kV DC transmission lines in the same corridor, the lateral distribution of the instantaneous maximal values of the hybrid electric field obtained with the proposed method fluctuates;the lateral distributions of the virtual values of the

  19. Effect of atomization gas pressure variation on gas flow field in supersonic gas atomization

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    In this paper, a computational fluid flow model was adopted to investigate the effect of varying atomization gas pressure (P0) on the gas flow field in supersonic gas atomization. The influence of P0 on static pressure and velocity magnitude of the central axis of the flow field was also examined. The numerical results indicate that the maximum gas velocity within the gas field increases with increasing P0. The aspiration pressure (ΔP) is found to decrease as P0 increases at a lower atomization gas pressure. However, at a higher atomization gas pressure increasing P0 causes the opposite: the higher atomization gas pressure, the higher aspiration pressure. The alternation of ΔP is caused by the variations of stagnation point pressure and location of Mach disk, while hardly by the location of stagnation point. A radical pressure gradient is formed along the tip of the delivery tube and increases as P0 increases.

  20. Dynamic subsidence prediction of ground surface above salt cavern gas storage considering the creep of rock salt

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A new model is proposed to predict the dynamic subsidence of ground surface above salt cavern gas storage during the leaching and storage, which takes into account the creep of rock salt. In the model, the extended form of Gaussian curve is adopted to figure out the shape of subsidence areas. The corresponding theoretical formulas are derived. In addition, parameters are studied to investigate the surface subsidence as a function of the salt ejection rate, internal pressure, buried depth, diameter, height, running time, etc. Through an example, the subsidence of the salt cavern gas storage located at Jiangsu of China obtained by the new model was compared with those by Peter A F formula, Schober & Sroka formula and FLAC3D through simulation. The results showed the proposed model is precise and correct, and can meet the actual engineering demands. The surface subsidence is equidirectional with the increase of salt ejection rate, depth, diameter, height, and running time, but reverse to the increase of internal pressure. The depth, diameter, running time and internal pressure have great effects on the subsidence, whereas the salt ejection rate and height have little influences on it.

  1. Effect of change in large and fast solar wind dynamic pressure on geosynchronous magnetic field

    Institute of Scientific and Technical Information of China (English)

    Borodkova N L; Liu Jing-Bo; Huang Zhao-Hui; Zastenker G N; Wang Chi; Eiges P E

    2006-01-01

    We present a comparison of changes in large and sharp solar wind dynamic pressure, observed by several spacecraft,with fast disturbances in the magnetospheric magnetic field, measured by the geosynchronous satellites. More than 260 changes in solar wind pressure during the period 1996-2003 are selected for this study. Large statistics show that an increase (a decrease) in dynamic pressure always results in an increase (a decrease) in the magnitude of geosynchronous magnetic field. The amplitude of response to the geomagnetic field strongly depends on the location of observer relative to the noon meridian, the value of pressure before disturbance, and the change in amplitude of pressure.

  2. Anomalous Response in Heteroacene-Based Organic Field Effect Transistors under High Pressure

    Directory of Open Access Journals (Sweden)

    Ken-ichi Sakai

    2014-04-01

    Full Text Available Carrier transport properties of organic field effect transistors in dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene single crystals have been investigated under high pressure. In contrast to the typical pressure effect of monotonic increase in charge transfer rates according to the application of external hydrostatic pressure, it is clarified that the present organic semiconductor devices exhibit nonmonotonic pressure response, such as negative pressure effect. X-ray diffraction analysis under high pressure reveals that on-site molecular orientation and displacement in the heteroacene molecule is assumed to be the origin for the anomalous pressure effects.

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

    OpenAIRE

    Nakano, K.; H. Chikatsu

    2015-01-01

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

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

    Science.gov (United States)

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

    2011-09-01

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

  5. Development of high-pressure, high-field and multifrequency electron spin resonance system.

    Science.gov (United States)

    Sakurai, T; Taketani, A; Tomita, T; Okubo, S; Ohta, H; Uwatoko, Y

    2007-06-01

    The electron spin resonance (ESR) system which covers the magnetic field region up to 16 T, the quasicontinuous frequency region from 60 to 700 GHz, the temperature region from 1.8 to 4.2 K, and the hydrostatic pressure region up to 1.1 GPa has been developed. This is the first pulsed high-field and multifrequency ESR system with the pressure region over 1 GPa as far as we know. Transmission ESR spectra under hydrostatic pressure can be obtained by combining a piston-cylinder-type pressure cell and the pulsed magnetic field ESR apparatus. The pressure cell consists of a NiCrAl cylinder and sapphire or zirconia inner parts. The use of sapphire or zirconia as inner parts enables us to observe ESR under pressure because these inner parts have high transmittance for the electromagnetic wave with millimeter and submillimeter wavelengths. We have successfully applied this system for the pressure dependence measurements of an isolated spin system NiSnCl(6)6H(2)O up to 1.1 GPa. It was found that the single ion anisotropy parameter D of this compound strongly depends on pressure. The parameter D is approximately proportional to the pressure up to 0.75 GPa, and the relation between D and the pressure can be used for the pressure calibration of this high-field and high-pressure ESR system.

  6. Propeller Cavitation in Non-Uniform Flow and Correlation with the Near Pressure Field

    Directory of Open Access Journals (Sweden)

    Francisco Alves Pereira

    2016-11-01

    Full Text Available An experimental study is carried out in a cavitation tunnel on a propeller operating downstream of a non-uniform wake. The goal of this work is to establish quantitative correlations between the near pressure field and the cavitation pattern that takes place on the propeller blades. The pressure field is measured at the walls of the test section and in the near wake of the propeller and is combined with quantitative high-speed image recording of the cavitation pattern. Through harmonic analysis of the pressure data and image processing techniques that allow retrieving the cavitation extension and volume, we discuss the potential sources that generate the pressure fluctuations. Time correlations are unambiguously established between pressure peak fluctuations and cavitation collapse events, based on the Rayleigh collapse time. Finally, we design a model to predict the cavitation-induced pressure fluctuations from the derivation of the cavitation volume acceleration. A remarkable agreement is observed with the actual pressure field.

  7. 3D pressure field in lipid membranes and membrane-protein complexes

    DEFF Research Database (Denmark)

    Ollila, O H Samuli; Risselada, H Jelger; Louhivuori, Martti

    2009-01-01

    We calculate full 3D pressure fields for inhomogeneous nanoscale systems using molecular dynamics simulation data. The fields represent systems with increasing level of complexity, ranging from semivesicles and vesicles to membranes characterized by coexistence of two phases, including also...... a protein-membrane complex. We show that the 3D pressure field is distinctly different for curved and planar bilayers, the pressure field depends strongly on the phase of the membrane, and that an integral protein modulates the tension and elastic properties of the membrane....

  8. On the Lamb vector divergence, evolution of pressure fields and Navier-Stokes regularity

    CERN Document Server

    Lindgren, Jussi

    2012-01-01

    This paper analyzes the Lamb vector divergence, also called the hydrodynamic charge density, and its implications to the Navier-Stokes system. It is shown that the pressure field can be always chosen in a way that ensures regularity of the Navier-Stokes system. The abstract pressure field that ensures regularity is defined through two partial differential equations, one of them being of the elliptic kind and the other one being an evolution equation. The pressure field defined such a way can be interpreted as a control potential field that keeps the system regular. The controlling pressure field depends only on the velocity field of the fluid and its derivatives, so that the result is applicable in any general setting where the initial data is divergence free, smooth and square-integrable.

  9. Geosynchronous magnetic field responses to fast solar wind dynamic pressure enhancements: MHD field model

    Directory of Open Access Journals (Sweden)

    T. R. Sun

    2012-08-01

    Full Text Available We performed global MHD simulations of the geosynchronous magnetic field in response to fast solar wind dynamic pressure (Pd enhancements. Taking three Pd enhancement events in 2000 as examples, we found that the main features of the total field B and the dominant component Bz can be efficiently predicted by the MHD model. The predicted B and Bz varies with local time, with the highest level near noon and a slightly lower level around mid-night. However, it is more challenging to accurately predict the responses of the smaller component at the geosynchronous orbit (i.e., Bx and By. In contrast, the limitations of T01 model in predicting responses to fast Pd enhancements are presented.

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

    Directory of Open Access Journals (Sweden)

    M.-O. Schmid

    2012-02-01

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

  11. High Pressure XENON Gamma-Ray Spectrometers for Field Use

    Energy Technology Data Exchange (ETDEWEB)

    David K. Wehe; Zong He; Glenn K. Knoll

    2004-02-16

    This project explored a new concept for high-pressure xenon ionization chambers by replacing the Frisch grid with coplanar grid electrodes similar to those used in wide bandgap semiconductor gamma-ray spectrometers. This work is the first attempt to apply the coplanar grid anode design in a gas ionization chamber in order to achieve to improved energy resolution. Three prototype detectors, two cylindrical and one parallel plate configurations, were built and tested. While the detectors did not demonstrate energy resolutions as good as other high pressure xenon gamma-ray spectrometers, the results demonstrated that the concept of single polarity charge sending using coplanar grid electrodes will work in a gas detector.

  12. Pressure of Degenerate and Relativistic electrons in a superhigh magnetic field

    CERN Document Server

    Gao, Zhi Fu; He, Peng Qiu; Jie, Du Yuan

    2013-01-01

    Based on our previous work, we deduce a general formula for pressure of degenerate and relativistic electrons,Pe, which is suitable for superhigh magnetic fields, discuss the quantization of Landau levels of electrons, and consider the quantum electrodynam-ic(QED) effects on the equations of states (EOSs) for different matter systems. The main conclusions are as follows:Pe is related to the magnetic field B, matter density ?, and electron fraction Ye ; the stronger the magnetic field, the higher the electron pressure becomes; the high electron pressure could be caused by high Fermi energy of electrons in a superhigh magnetic field; compared with a common radio pulsar, a magnetar could be a more compact oblate spheroid-like deformed neutron star due to the anisotropic total pressure; and an increase in the maximum mass of a magnetar is expected because of the positive contribution of the magnetic field energy to the EOS of the star.

  13. Contribution of ground surface altitude difference to thermal anomaly detection using satellite images: Application to volcanic/geothermal complexes in the Andes of Central Chile

    Science.gov (United States)

    Gutiérrez, Francisco J.; Lemus, Martín; Parada, Miguel A.; Benavente, Oscar M.; Aguilera, Felipe A.

    2012-09-01

    Detection of thermal anomalies in volcanic-geothermal areas using remote sensing methodologies requires the subtraction of temperatures, not provided by geothermal manifestations (e.g. hot springs, fumaroles, active craters), from satellite image kinetic temperature, which is assumed to correspond to the ground surface temperature. Temperatures that have been subtracted in current models include those derived from the atmospheric transmittance, reflectance of the Earth's surface (albedo), topography effect, thermal inertia and geographic position effect. We propose a model that includes a new parameter (K) that accounts for the variation of temperature with ground surface altitude difference in areas where steep relief exists. The proposed model was developed and applied, using ASTER satellite images, in two Andean volcanic/geothermal complexes (Descabezado Grande-Cerro Azul Volcanic Complex and Planchón-Peteroa-Azufre Volcanic Complex) where field data of atmosphere and ground surface temperature as well as radiation for albedo calibration were obtained in 10 selected sites. The study area was divided into three zones (Northern, Central and Southern zones) where the thermal anomalies were obtained independently. K value calculated for night images of the three zones are better constrained and resulted to be very similar to the Environmental Lapse Rate (ELR) determined for a stable atmosphere (ELR > 7 °C/km). Using the proposed model, numerous thermal anomalies in areas of ≥ 90 m × 90 m were identified that were successfully cross-checked in the field. Night images provide more reliable information for thermal anomaly detection than day images because they record higher temperature contrast between geothermal areas and its surroundings and correspond to more stable atmospheric condition at the time of image acquisition.

  14. Mathematical Modeling of the Pressure Field Generated by Ocean Wave at the Bottom of the Ocean

    Institute of Scientific and Technical Information of China (English)

    龚沈光; 唐劲飞; 颜冰

    2002-01-01

    This paper develops a new method for calculating the pressure-tirme processof the pressure field generated by ocean wave at sea bottom based on the surface wavespectrum of the ocean wave. The basic assumptions of modeling are that the surfaceocean wave pressure equals to the atmospheric pressure and that the viscidity of seawater is neglected. The steps of modeling are described below. First the power spectraldensity of ocean wave is discretized and the amplitude spectra of harmonic ocean waveare obtained. Then the amplitude spectra of harmonic pressure are obtained accordingto the amplitude spectrum of surface wave and the depth of the sea. Finally, based onthe oceanographic theory of representing a fixed wave surface by summing up random-phase sinusoids, the pressure-time process of pressure field at sea bottom is obtained bysumming up the amplitude spectrum of pressure. The paper also develops a method ofdetermining the relationship between mean wave period and wave heights undershallow water condition, thus the pressure-time process of pressure field produced bynon-well-developed ocean wave can be directly calculated once the mean wave heightand period are known.

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

    Directory of Open Access Journals (Sweden)

    M. Ramos

    2008-03-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-07-01

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

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

    Science.gov (United States)

    Muggleton, J. M.; Papandreou, B.

    2014-07-01

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

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

    Science.gov (United States)

    Ramos, M.; Vieira, G.

    2008-03-01

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

  19. Influence of Pressure Field in Melts on the Primary Nucleation in Solidification Processing

    Science.gov (United States)

    Rakita, Milan; Han, Qingyou

    2017-10-01

    It is well known that external fields applied to melts can cause nucleation at lower supercoolings, fragmentation of growing dendrites, and forced convection around the solidification front. All these effects contribute to a finer microstructure of solidified material. In this article, we analyze how the pressure field created with ultrasonic vibrations influences structure refinement in terms of supercooling. It is shown that only high cavitation pressures of the order of 104 atmospheres are capable of nucleating crystals at minimal supercoolings. We demonstrate the possibility of sononucleation even in superheated liquid. Simulation and experiments with water samples show that very high cavitation pressures occur in a relatively narrow zone where the drive acoustic field has an appropriate combination of pressure amplitude and frequency. In order to accurately predict the microstructure formed by ultrasonically assisted solidification of metals, this article calls for the development of equations of state that would describe the pressure-dependent behavior of molten metals.

  20. Measurement and Modeling of the Fluctuating Wall Pressure Field Beneath Transitional Boundary Layers

    Science.gov (United States)

    Snarski, Stephen R.

    2001-11-01

    Measurements have been performed to better understand the space-varying character of the fluctuating wall pressure field beneath a transitional boundary layer and to develop an appropriate model for the space-varying (nonhomogeneous) wavenumber-frequency wall pressure spectrum. Although a great deal is understood regarding the structure of the wall pressure field beneath turbulent boundary layers, the current understanding of the wall pressure field beneath the transitional boundary layer is incomplete. Overlooked have been critical issues concerning spatial variations in turbulence structure and the convection and decay of pressure producing disturbances—properties that define the character of the field and resulting form of the wavenumber-frequency spectrum. The experiments involve measurement of the space-time fluctuating wall pressure field across the transition region of a flat plate boundary layer by means of a 64-element linear array of hearing-aid microphones and hot wire velocity measurements in the adjacent laminar, transitional, and turbulent boundary layers. Because the field is nonhomogeneous, wavelet based transform methods are required to appropriately resolve the space-varying structure of the field and form of the nonhomogeneous wavenumber-frequency spectrum.

  1. Anisotropy and pressure dependence of the upper critical field of the ferromagnetic superconductor UGe2

    Science.gov (United States)

    Sheikin, I.; Huxley, A.; Braithwaite, D.; Brison, J. P.; Watanabe, S.; Miyake, K.; Flouquet, J.

    2001-12-01

    The temperature and pressure dependence of the upper critical field, Hc2, of the ferromagnetic superconductor UGe2 is reported for fields applied along all three crystallographic axes. For fields parallel to the easy magnetic a axis, the relationship between an unusual reentrant behavior of Hc2 and a field-induced transition associated with a change in the electronic density of states is reviewed. For transverse field directions a significant evolution in the behavior of Hc2 with pressure is found. As the pressure is decreased the dependence of Hc2 on temperature for fields along the crystal's c axis acquires a positive curvature that extends from the critical temperature, Tc, down to almost the lowest temperature measured (Tc/10) where Hc2 exceeds the usual weak coupling paramagnetic and orbital limits.

  2. Intraband optical absorption in a single quantum ring: Hydrostatic pressure and intense laser field effects

    Science.gov (United States)

    Barseghyan, M. G.

    2016-11-01

    The intraband optical absorption in GaAs/Ga0.7Al0.3As two-dimensional single quantum ring is investigated. Considering the combined effects of hydrostatic pressure and intense laser field the energy of the ground and few excited states has been found using the effective mass approximation and exact diagonalization technique. The energies of these states and the corresponding threshold energy of the intraband optical transitions are examined as a function of hydrostatic pressure for the different values of the laser field parameter. We also investigated the dependencies of the intraband optical absorption coefficient as a function of incident photon energy for different values of hydrostatic pressure and laser field parameter. It is found that the effects of hydrostatic pressure and intense laser field lead to redshift and blueshift of the intraband optical spectrum respectively.

  3. Modeling transducer impulse responses for predicting calibrated pressure pulses with the ultrasound simulation program Field II

    DEFF Research Database (Denmark)

    Bæk, David; Jensen, Jørgen Arendt; Willatzen, Morten

    2010-01-01

    FIELD II is a simulation software capable of predicting the field pressure in front of transducers having any complicated geometry. A calibrated prediction with this program is, however, dependent on an exact voltage-to-surface acceleration impulse response of the transducer. Such impulse response...... is not calculated by FIELD II. This work investigates the usability of combining a one-dimensional multilayer transducer modeling principle with the FIELD II software. Multilayer here refers to a transducer composed of several material layers. Measurements of pressure and current from Pz27 piezoceramic disks...... as well as pressure and intensity measurements in front of a 128 element commercial convex medical transducer are compared to the simulations. Results show that the models can predict the pressure from the piezoceramic disks with a root mean square (rms) error of 11.2% to 36.2% with a 2 dB amplitude...

  4. Pressure-field extraction from Lagrangian flow measurements: first experiences with 4D-PTV data

    Science.gov (United States)

    Neeteson, N. J.; Bhattacharya, S.; Rival, D. E.; Michaelis, D.; Schanz, D.; Schröder, A.

    2016-06-01

    As a follow-up to a previous proof-of-principle study, a novel Lagrangian pressure-extraction technique is analytically evaluated, and experimentally validated using dense 4D-PTV data. The technique is analytically evaluated using the semi-three-dimensional Taylor-Green vortex, and it is found that the Lagrangian technique out-performs the standard Eulerian technique when Dirichlet boundary conditions are enforced. However, the Lagrangian technique produces worse estimates of the pressure field when Neumann boundary conditions are enforced on boundaries with strong pressure gradients. The technique is experimentally validated using flow data obtained for the case of a free-falling, index-matched sphere at Re=2100. The experimental data were collected using a four-camera particle tracking velocimetry measurement system, and processed using 4D-PTV. The pressure field is then extracted using both the Eulerian and Lagrangian techniques, and the resulting pressure fields are compared. Qualitatively, the pressure fields agree; however, quantitative differences are found with respect to the magnitude of the pressure minima on the side of the sphere. Finally, the pressure-drag coefficient is estimated using each technique, and the two techniques are found to be in very close agreement. A comparison to a reference value from literature confirms that the drag coefficient estimates are reasonable, demonstrating the validity of the technique.

  5. Calculation of pressure fields from arbitrarily shaped, apodized, and excited ultrasound transducers

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt; Svendsen, Niels Bruun

    1992-01-01

    A method for simulation of pulsed pressure fields from arbitrarily shaped, apodized and excited ultrasound transducers is suggested. It relies on the Tupholme-Stepanishen method for calculating pulsed pressure fields, and can also handle the continuous wave and pulse-echo case. The field...... is calculated by dividing the surface into small rectangles and then Summing their response. A fast calculation is obtained by using the far-field approximation. Examples of the accuracy of the approach and actual calculation times are given...

  6. Spatial heterogeneity of four-dimensional relative pressure fields in the human left ventricle.

    Science.gov (United States)

    Eriksson, Jonatan; Bolger, Ann F; Carlhäll, Carl-Johan; Ebbers, Tino

    2015-12-01

    To assess the spatial heterogeneity of the four-dimensional (4D) relative pressure fields in the healthy human left ventricle (LV) and provide reference data for normal LV relative pressure. Twelve healthy subjects underwent a cardiac MRI examination where 4D flow and morphological data were acquired. The latter data were segmented and used to define the borders of the LV for computation of relative pressure fields using the pressure Poisson equation. The LV lumen was divided into 17 pie-shaped segments. In the normal left ventricle, the relative pressure in the apical segments was significantly higher relative to the basal segments (P pressure than the opposite basal inferolateral segment during both E-wave (P Relative pressure in the left ventricle is heterogeneous. During diastole, the main pressure differences in the LV occur along the basal-apical axis. However, pressure differences were also found in the short axis direction and may reflect important aspects of atrioventricular coupling. Additionally, this study provides reference data on LV pressure dynamics for a group of healthy subjects. © 2014 Wiley Periodicals, Inc.

  7. Experimental field investigation of pressure maintenance, peripheral flooding and pattern flooding at Uzen Field

    Energy Technology Data Exchange (ETDEWEB)

    Osadchii, A.I.; Teslyuk, E.V.; Ilyaev, V.I.

    1967-08-01

    A pilot water injection project involving 8 wells was conducted to determine water injection rates and pressures, parting pressure of the formation, and degree of formation cooling by the injected water. Satisfactory water injection rates resulted only at pressures high enough to fracture the formation. However, a uniform water front resulted even in presence of fractures. The injected water cooled the formation around the well from 65/sup 0/C to 20/sup 0/C. When water injection ceased, well-bottom temperature rose slowly. At present, not enough supply water is available for the pressure maintenance program. Steps are being taken to solve this problem.

  8. Experimental Verification of the Role of Electron Pressure in Fast Magnetic Reconnection with a Guide Field.

    Science.gov (United States)

    Fox, W; Sciortino, F; V Stechow, A; Jara-Almonte, J; Yoo, J; Ji, H; Yamada, M

    2017-03-24

    We report detailed laboratory observations of the structure of a reconnection current sheet in a two-fluid plasma regime with a guide magnetic field. We observe and quantitatively analyze the quadrupolar electron pressure variation in the ion-diffusion region, as originally predicted by extended magnetohydrodynamics simulations. The projection of the electron pressure gradient parallel to the magnetic field contributes significantly to balancing the parallel electric field, and the resulting cross-field electron jets in the reconnection layer are diamagnetic in origin. These results demonstrate how parallel and perpendicular force balance are coupled in guide field reconnection and confirm basic theoretical models of the importance of electron pressure gradients for obtaining fast magnetic reconnection.

  9. Challenges in estimating insecticide selection pressures from mosquito field data.

    Directory of Open Access Journals (Sweden)

    Susana Barbosa

    2011-11-01

    Full Text Available Insecticide resistance has the potential to compromise the enormous effort put into the control of dengue and malaria vector populations. It is therefore important to quantify the amount of selection acting on resistance alleles, their contributions to fitness in heterozygotes (dominance and their initial frequencies, as a means to predict the rate of spread of resistance in natural populations. We investigate practical problems of obtaining such estimates, with particular emphasis on Mexican populations of the dengue vector Aedes aegypti. Selection and dominance coefficients can be estimated by fitting genetic models to field data using maximum likelihood (ML methodology. This methodology, although widely used, makes many assumptions so we investigated how well such models perform when data are sparse or when spatial and temporal heterogeneity occur. As expected, ML methodologies reliably estimated selection and dominance coefficients under idealised conditions but it was difficult to recover the true values when datasets were sparse during the time that resistance alleles increased in frequency, or when spatial and temporal heterogeneity occurred. We analysed published data on pyrethroid resistance in Mexico that consists of the frequency of a Ile1,016 mutation. The estimates for selection coefficient and initial allele frequency on the field dataset were in the expected range, dominance coefficient points to incomplete dominance as observed in the laboratory, although these estimates are accompanied by strong caveats about possible impact of spatial and temporal heterogeneity in selection.

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

    Directory of Open Access Journals (Sweden)

    Balgaisha Mukanova

    2017-01-01

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

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

    Science.gov (United States)

    Ramos, M.; Vieira, G.

    2009-05-01

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

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

    Directory of Open Access Journals (Sweden)

    M. Ramos

    2009-05-01

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

  13. High-field Zeeman and Paschen-Back effects at high pressure in oriented ruby

    Science.gov (United States)

    Millot, Marius; Broto, Jean-Marc; Gonzalez, Jesus

    2008-10-01

    High-field Zeeman and Paschen-Back effects have been observed in single crystals of ruby submitted to hydrostatic pressure up to 10 GPa. A specific setup with a miniature diamond-anvil cell has been developed to combine high pressure and pulsed magnetic fields and to perform magnetophotoluminescence measurements. Careful analysis of low-temperature (4.2 and 77 K) photoluminescence spectra with a 56 T magnetic field applied along the c axis allows for the rectification of the assignment of observed emission lines to corresponding Zeeman-split levels. Besides, the intrinsic Zeeman-splitting factors of excited states reveal a linear pressure-induced increase. This enhancement is a signature of an increase in trigonal distortion induced by hydrostatic pressure. Moreover, spectra with magnetic field perpendicular to crystallographic c axis exhibit a Paschen-Back effect reflecting the progressive alignment of Cr3+ ions spin along the applied field. However, no pressure modification is observed in this compound, contrarily to the Heisenberg-to-Ising spin character pressure-induced transition observed in alexandrite.

  14. Characteristics of Abnormal Pressure Systems and Their Responses of Fluid in Huatugou Oil Field, Qaidam Basin

    Institute of Scientific and Technical Information of China (English)

    CHEN Xiaozhi; XU Hao; TANG Dazhen; ZHANG Junfeng; HU Xiaolan; TAO Shu; CAI Yidong

    2009-01-01

    Based on the comprehensive study of core samples, well testing data, and reservoir fluid properties, the construction and the distribution of the abnormal pressure systems of the Huatugou oil field in Qaidam Basin are discussed. The correlation between the pressure systems and hydrocarbon accumulation is addressed by analyzing the corresponding fluid characteristics. The results show that the Huatugou oil field as a whole has low formation pressure and low fluid energy; therefore, the hydrocarbons are hard to migrate, which facilitates the forming of primary reservoirs. The study reservoirs, located at the Xiayoushashan Formation (N_2~1) and the Shangganchaigou Formation (N_1) are relatively shallow and have medium porosity and low permeability. They are abnormal low-pressure reservoirs with an average formation pressure coefficient of 0.61 and 0.72 respectively. According to the pressure coefficient and geothermal anomaly, the N_1 and N_2~1 Formations belong to two independent temperature-pressure systems, and the former has slightly higher energy. The low-pressure compartments consist of a distal bar as the main body, prodeita mud as the top boundary, and shore and shallow lake mud or algal mound as the bottom boundary. They are vertically overlapped and horizontally paralleled. The formation water is abundant in the Cl~- ion and can be categorized as CaCl_2 type with high salinity, which indicates that the abnormal low-pressure compartments are in good sealing condition and beneficial for oil and gas accumulation and preservation.

  15. 3D Pressure Field in Lipid Membranes and Membrane-Protein Complexes

    NARCIS (Netherlands)

    Ollila, O. H. Samuli; Risselada, H. Jelger; Louhivuori, Martti; Lindahl, Erik; Vattulainen, Ilpo; Marrink, Siewert J.

    2009-01-01

    We calculate full 3D pressure fields for inhomogeneous nanoscale systems using molecular dynamics simulation data. The fields represent systems with increasing level of complexity, ranging from semivesicles and vesicles to membranes characterized by coexistence of two phases, including also a protei

  16. Field measurement of local ice pressures on the ARAON in the Beaufort Sea

    Directory of Open Access Journals (Sweden)

    Lee Tak-Kee

    2014-12-01

    Full Text Available This study conducted four field measurements of local ice pressure during the icebreaking voyage of the icebreaking research vessel “ARAON” in the Chukchi and Beaufort seas from July to August of 2010. For measurements, 14 strain gauges, including 8 strain gauge rosettes, were set on the bow of the port side. Influence coefficients were determined using a finite element model of the instrumented area and they were used to convert the measured strains on the hull structure to local ice pressures. The converted maximum pressure was calculated as 2.12 MPa on an area of 0.28 m2. Pressure-area curves were developed from the surveyed pressure data and the results were compared with previously measured data. The study results are expected to provide an understanding of local ice pressures and thus be useful in the structural design of ice class ships.

  17. Pressure and electric field effects on piezoelectric responses of KNbO3

    Science.gov (United States)

    Liang, Linyun; Li, Y. L.; Xue, Fei; Chen, Long-Qing

    2012-09-01

    The dielectric and piezoelectric properties of a KNbO3 single crystal under applied hydrostatic pressure and positive bias electric field are investigated using phenomenological Landau-Ginzburg-Devonshire thermodynamic theory. It is shown that the hydrostatic pressure effect on the dielectric and piezoelectric properties is similar to temperature, suggesting a common underlying mechanism for the piezoelectric anisotropy and its enhancement. The stable phase diagram of KNbO3 as a function of temperature and positive bias electric field is constructed. The maximum piezoelectric coefficient d33o* varying with temperature and electric field is calculated.

  18. Near-field acoustic holography with sound pressure and particle velocity measurements

    DEFF Research Database (Denmark)

    Fernandez Grande, Efren

    of particle velocity measurements and combined pressure-velocity measurements in NAH, the relation between the near-field and the far-field radiation from sound sources via the supersonic acoustic intensity, and finally, the reconstruction of sound fields using rigid spherical microphone arrays. Measurement...... of the particle velocity has notable potential in NAH, and furthermore, combined measurement of sound pressure and particle velocity opens a new range of possibilities that are examined in this study. On this basis, sound field separation methods have been studied, and a new measurement principle based on double...... layer measurements of the particle velocity has been proposed. Also, the relation between near-field and far-field radiation from sound sources has been examined using the concept of the supersonic intensity. The calculation of this quantity has been extended to other holographic methods, and studied...

  19. Modeling and Experimental Investigation of Pressure Field in the Grinding Zone with Nanoparticle Jet of MQL

    Directory of Open Access Journals (Sweden)

    C. H. Li

    2013-01-01

    Full Text Available Solid nano particles were added in minimum quantity lubrication (MQL fluid medium to make nanofluids, that is, after the mixing and atomization of nanoparticle, lubricants and high pressure gas, to inject solid nano particle in the grinding zone with the form of jet flow. The mathematical model of two-phase flow pressure field of grinding zone with nanoparticle jet flow of MQL was established, and the simulation study was conducted. The results show that pressures in the grinding zone increased with the acceleration of grinding wheel, sharply decreased with the increased minimum clearance, and increased with the acceleration of jet flow. At three spraying angles of nozzles, when the nozzle angle was 15°, the pressure of grinding zone along the speed of grinding wheel was larger than the rest two angles. On the experimental platform built by KP-36 precision grinder and nanoparticle jet flow feed way, CY3018 pressure sensor was used to test the regularities of pressure field variations. The impact of the speed of grinding wheel, the gap between workpiece and grinding wheel, jet flow velocity, and spraying angles of nozzles on the pressure field of grinding zone was explored. The experimental result was generally consistent with the theoretical simulation, which verified the accuracy of the theoretical analysis.

  20. Low pressure arc discharge lamp apparatus with magnetic field generating means

    Science.gov (United States)

    Grossman, M.W.; George, W.A.; Maya, J.

    1987-10-06

    A low-pressure arc discharge apparatus having a magnetic field generating means for increasing the output of a discharge lamp is disclosed. The magnetic field generating means, which in one embodiment includes a plurality of permanent magnets, is disposed along the lamp for applying a constant transverse magnetic field over at least a portion of the positive discharge column produced in the arc discharge lamp operating at an ambient temperature greater than about 25 C. 3 figs.

  1. Direct analysis of dispersive wave fields from near-field pressure measurements

    NARCIS (Netherlands)

    Horchens, L.

    2011-01-01

    Flexural waves play a significant role for the radiation of sound from plates. The analysis of flexural wave fields enables the detection of sources and transmission paths in plate-like structures. The measurement of these wave fields can be carried out indirectly by means of near-field acoustic hol

  2. Field Aligned Currents Derived from Pressure Profiles Obtained from TWINS ENA Images

    Science.gov (United States)

    Wood, K.; Perez, J. D.; McComas, D. J.; Goldstein, J.; Valek, P. W.

    2015-12-01

    Field aligned currents (FACs) that flow from the Earth's magnetosphere into the ionosphere are an important coupling mechanism in the interaction of the solar wind with the Earth's magnetosphere. Assuming pressure balance along with charge conservation yields an expression for the FACs in terms of plasma pressure gradients and pressure anisotropy. The Two Wide-Angle Imaging Neutral Atom Spectrometers (TWINS) mission, the first stereoscopic ENA magnetospheric imager, provides global images of the inner magnetosphere from which ion pressure distributions and pressure anisotropies can be obtained. Following the formulations in Heineman [1990] and using results from TWINS observations, we calculate the distribution of field aligned currents for the 17-18 March 2015 geomagnetic storm in which extended ionospheric precipitation was observed. Initial results for the field aligned currents will be generated assuming an isotropic pitch angle distribution. Global maps of field aligned currents during the main and recovery phase of the storm will be presented. Heinemann, H. (1990), Representations of Currents and Magnetic Fields in Anisotropic Magnetohydrostatic Plasma, J. Geophys. Res., 95, 7789.

  3. How the bending kinematics of swimming lampreys build negative pressure fields for suction thrust.

    Science.gov (United States)

    Gemmell, Brad J; Fogerson, Stephanie M; Costello, John H; Morgan, Jennifer R; Dabiri, John O; Colin, Sean P

    2016-12-15

    Swimming animals commonly bend their bodies to generate thrust. For undulating animals such as eels and lampreys, their bodies bend in the form of waves that travel from head to tail. These kinematics accelerate the flow of adjacent fluids, which alters the pressure field in a manner that generates thrust. We used a comparative approach to evaluate the cause-and-effect relationships in this process by quantifying the hydrodynamic effects of body kinematics at the body-fluid interface of the lamprey, Petromyzon marinus, during steady-state swimming. We compared the kinematics and hydrodynamics of healthy control lampreys to lampreys whose spinal cord had been transected mid-body, resulting in passive kinematics along the posterior half of their body. Using high-speed particle image velocimetry (PIV) and a method for quantifying pressure fields, we detail how the active bending kinematics of the control lampreys were crucial for setting up strong negative pressure fields (relative to ambient fields) that generated high-thrust regions at the bends as they traveled all along the body. The passive kinematics of the transected lamprey were only able to generate significant thrust at the tail, relying on positive pressure fields. These different pressure and thrust scenarios are due to differences in how active versus passive body waves generated and controlled vorticity. This demonstrates why it is more effective for undulating lampreys to pull, rather than push, themselves through the fluid. © 2016. Published by The Company of Biologists Ltd.

  4. Experimental demonstration of the role of electron pressure in fast magnetic reconnection with a guide field

    Science.gov (United States)

    Fox, W.; Sciortino, F.; von Stechow, A.; Jara-Almonte, J.; Yoo, J.; Ji, H.; Yamada, M.

    2016-10-01

    We report detailed laboratory observations of the structure of reconnection current sheets in a two-fluid plasma regime with a guide magnetic field, conducted on the Magnetic Reconnection Experiment. We observe in the laboratory for the first time the quadrupolar electron pressure variation in the ion-diffusion region, as originally predicted by extended MHD simulation. We quantitatively analyze the parallel and perpendicular force balance, and observe the projection of the electron pressure gradient parallel to the B field balances the parallel electric field. The resulting cross-field electron jets in the reconnection layer are diamagnetic in origin. Electron density variations are observed to dominate temperature variations and may provide a new diagnostic of reconnection with finite guide field for fusion experiments and spacecraft missions. Supported by Max-Planck Princeton Center for Plasma Physics.

  5. Crystal fields of Pr sup 3 sup + in LiYF sub 4 under pressure

    CERN Document Server

    Tröster, T

    2003-01-01

    Fluorescence spectra of LiYF sub 4 :Pr sup 3 sup + have been measured between 12,000 and 22,000 cm sup - sup 1 under pressures up to 10 GPa. In total, 25 crystal field energy levels were obtained and used for the determination of free-ion and crystal field parameters under pressure. According to the nephelauxetic effect, the free-ion parameters decrease with increasing pressure. The relative decrease is larger for the Slater than for the spin-orbit coupling parameter. This behavior is consistent with former studies on Pr sup 3 sup + in different crystals and can be explained by a special covalency model. According to an effective D sub 2 sub d symmetry, five crystal field parameters B sub 0 sup 2 (f,f), B sub 0 sup 4 (f,f), B sub 4 sup 4 (f,f), B sub 0 sup 6 (f,f), and B sub 4 sup 6 (f,f) are non-zero. The pressure-induced changes of these parameters have been determined up to the maximum pressure of 10 GPa. In order to improve the calculation of the crystal field levels, the configuration interactions with t...

  6. Remote sensing of a low pressure plasma in the radio near field

    Science.gov (United States)

    Kelly, Seán; McNally, Patrick J.

    2017-09-01

    A novel approach to remotely monitor low pressure non-equilibrium plasmas is reported. A magnetic field antenna is positioned in the near field of a capacitively coupled plasma. Magnetic flux from plasma currents, present near the viewport, is intercepted by a calibrated loop antenna placed outside the chamber. The induced signal current is correlated to bulk plasma currents. The comparison of relative harmonic amplitudes shows resonance features for lower operating pressures. The geometric resonance and electron-neutral collision frequencies are evaluated from resonant harmonic features. This approach advances remote, noninvasive, and installation-free plasma monitoring, which is of particular interest to industrial scenarios.

  7. Field Evaluation of Ultra-High Pressure Water Systems for Runway Rubber Removal

    Science.gov (United States)

    2014-04-01

    ER D C/ G SL T R- 14 -1 1 Field Evaluation of Ultra-High Pressure Water Systems for Runway Rubber Removal G eo te ch ni ca l a nd S tr...Field Evaluation of Ultra-High Pressure Water Systems for Runway Rubber Removal Aaron B. Pullen Applied Research Associates, Inc. 421 Oak Avenue...Engineer Center Tyndall Air Force Base, FL 32403-5319 ERDC/GSL TR-14-11 ii Abstract Runway rubber removal is a maintenance function employed to

  8. Quantitative measurement of ultrasound pressure field by optical phase contrast method and acoustic holography

    Science.gov (United States)

    Oyama, Seiji; Yasuda, Jun; Hanayama, Hiroki; Yoshizawa, Shin; Umemura, Shin-ichiro

    2016-07-01

    A fast and accurate measurement of an ultrasound field with various exposure sequences is necessary to ensure the efficacy and safety of various ultrasound applications in medicine. The most common method used to measure an ultrasound pressure field, that is, hydrophone scanning, requires a long scanning time and potentially disturbs the field. This may limit the efficiency of developing applications of ultrasound. In this study, an optical phase contrast method enabling fast and noninterfering measurements is proposed. In this method, the modulated phase of light caused by the focused ultrasound pressure field is measured. Then, a computed tomography (CT) algorithm used to quantitatively reconstruct a three-dimensional (3D) pressure field is applied. For a high-intensity focused ultrasound field, a new approach that combines the optical phase contrast method and acoustic holography was attempted. First, the optical measurement of focused ultrasound was rapidly performed over the field near a transducer. Second, the nonlinear propagation of the measured ultrasound was simulated. The result of the new approach agreed well with that of the measurement using a hydrophone and was improved from that of the phase contrast method alone with phase unwrapping.

  9. Physical Limitations of Empirical Field Models: Force Balance and Plasma Pressure

    Energy Technology Data Exchange (ETDEWEB)

    Sorin Zaharia; C.Z. Cheng

    2002-06-18

    In this paper, we study whether the magnetic field of the T96 empirical model can be in force balance with an isotropic plasma pressure distribution. Using the field of T96, we obtain values for the pressure P by solving a Poisson-type equation {del}{sup 2}P = {del} {center_dot} (J x B) in the equatorial plane, and 1-D profiles on the Sun-Earth axis by integrating {del}P = J x B. We work in a flux coordinate system in which the magnetic field is expressed in terms of Euler potentials. Our results lead to the conclusion that the T96 model field cannot be in equilibrium with an isotropic pressure. We also analyze in detail the computation of Birkeland currents using the Vasyliunas relation and the T96 field, which yields unphysical results, again indicating the lack of force balance in the empirical model. The underlying reason for the force imbalance is likely the fact that the derivatives of the least-square fitted model B are not accurate predictions of the actual magnetospheric field derivatives. Finally, we discuss a possible solution to the problem of lack of force balance in empirical field models.

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

    Science.gov (United States)

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

    2016-04-01

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

  11. Bedrock geology Forsmark. Modelling stage 2.3. Description of the bedrock geological map at the ground surface

    Energy Technology Data Exchange (ETDEWEB)

    Stephens, Michael B.; Bergman, Torbjoern (Geological Survey of Sweden, Uppsala (Sweden)); Isaksson, Hans (GeoVista AB, Luleaa (Sweden)); Petersson, Jesper (SwedPower AB, Stockholm (Sweden))

    2008-12-15

    A description of the bedrock geological map of the ground surface at the Forsmark site is presented here. This map is essentially a 2D model for the distribution of different types of rock unit on this surface. Besides showing the distribution of these rock units, the bedrock geological map also displays the distribution of some deformation zones that intersect the ground surface. It also presents information bearing on the position and form of outcrops, the location and projection of boreholes drilled during the site investigation programme, subordinate rock types, the occurrence of abandoned mines or exploration prospects, measurements of ductile structures in outcrops, inferred form lines, key minerals, and the occurrence of mylonite and cataclastic rock. Bedrock data from outcrops and excavations, airborne and ground magnetic data and information from the uppermost part of boreholes have all been used in the construction of the geological map. The description has also made use of complementary analytical data bearing on the composition and age of the rocks as well gamma-ray spectrometry and gravity data. Uncertainty in the position of the boundaries between rock units over the mapped area are addressed in a qualitative manner. Four model versions of the bedrock geological map have been delivered to SKB's GIS database (bedrock geological map, Forsmark, versions 1.1, 1.2, 2.2 and 2.3) at different times during the site investigation programme. The Forsmark area is situated along the coast of the Baltic Sea in northern Uppland, Sweden, in a region where the overall level of ductile strain in the bedrock is high. This high-strain region extends several tens of kilometres across the WNW-ENE to NW-SE strike of the rocks in this part of the Fennoscandian Shield. At Forsmark, the coastal region is composed partly of high-strain belts, which formed under amphibolite-facies metamorphic conditions, and partly of tectonic lenses, where the bedrock is also affected by

  12. Reconstruction of an acoustic pressure field in a resonance tube by particle image velocimetry.

    Science.gov (United States)

    Kuzuu, K; Hasegawa, S

    2015-11-01

    A technique for estimating an acoustic field in a resonance tube is suggested. The estimation of an acoustic field in a resonance tube is important for the development of the thermoacoustic engine, and can be conducted employing two sensors to measure pressure. While this measurement technique is known as the two-sensor method, care needs to be taken with the location of pressure sensors when conducting pressure measurements. In the present study, particle image velocimetry (PIV) is employed instead of a pressure measurement by a sensor, and two-dimensional velocity vector images are extracted as sequential data from only a one- time recording made by a video camera of PIV. The spatial velocity amplitude is obtained from those images, and a pressure distribution is calculated from velocity amplitudes at two points by extending the equations derived for the two-sensor method. By means of this method, problems relating to the locations and calibrations of multiple pressure sensors are avoided. Furthermore, to verify the accuracy of the present method, the experiments are conducted employing the conventional two-sensor method and laser Doppler velocimetry (LDV). Then, results by the proposed method are compared with those obtained with the two-sensor method and LDV.

  13. Multivariate stationary non-Gaussian process simulation for wind pressure fields

    Science.gov (United States)

    Sun, Ying; Su, Ning; Wu, Yue

    2016-12-01

    Stochastic simulation is an important means of acquiring fluctuating wind pressures for wind induced response analyses in structural engineering. The wind pressure acting on a large-span space structure can be characterized as a stationary non-Gaussian field. This paper reviews several simulation algorithms related to the Spectral Representation Method (SRM) and the Static Transformation Method (STM). Polynomial and Exponential transformation functions (PSTM and ESTM) are discussed. Deficiencies in current algorithms, with respect to accuracy, stability and efficiency, are analyzed, and the algorithms are improved for better practical application. In order to verify the improved algorithm, wind pressure fields on a large-span roof are simulated and compared with wind tunnel data. The simulation results fit well with the wind tunnel data, and the algorithm accuracy, stability and efficiency are shown to be better than those of current algorithms.

  14. Near field acoustic holography based on the equivalent source method and pressure-velocity transducers

    DEFF Research Database (Denmark)

    Zhang, Y.-B.; Chen, X.-Z.; Jacobsen, Finn

    2009-01-01

    on particle velocity input data than when it is based on measurements of sound pressure data, and this is confirmed by a simulation study and by experimental results. A method that combines pressure- and particle velocity-based reconstructions in order to distinguish between contributions to the sound field......The advantage of using the normal component of the particle velocity rather than the sound pressure in the hologram plane as the input of conventional spatial Fourier transform based near field acoustic holography (NAH) and also as the input of the statistically optimized variant of NAH has...... recently been demonstrated. This paper examines whether there might be a similar advantage in using the particle velocity as the input of NAH based on the equivalent source method (ESM). Error sensitivity considerations indicate that ESM-based NAH is less sensitive to measurement errors when it is based...

  15. Pressure Evolution of a Field-Induced Fermi Surface Reconstruction and of the Neel Critical Field in CeIn3

    Energy Technology Data Exchange (ETDEWEB)

    Petrovic, C.; Purcell, K.M.; Graf, D.; Kano, M.; Bourg, J.; Palm, E.C.; Murphy, T.; McDonald, R.; Mielke, C.H.; Altarawneh, M.M.; Hu, R.; Ebihara, T.; Cooley, J.; Schlottmann, P.; Tozer, S.W.

    2009-06-01

    We report high-pressure skin-depth measurements on the heavy fermion material CeIn{sub 3} in magnetic fields up to 64 T using a self-resonant tank circuit based on a tunnel diode oscillator. At ambient pressure, an anomaly in the skin depth is seen at 45 T. The field where this anomaly occurs decreases with applied pressure until approximately 1.0 GPa, where it begins to increase before merging with the antiferromagnetic phase boundary. Possible origins for this transport anomaly are explored in terms of a Fermi surface reconstruction. The critical magnetic field at which the Neel-ordered phase is suppressed, is also mapped as a function of pressure and extrapolates to the previous ambient-pressure measurements at high magnetic fields and high-pressure measurements at zero magnetic field.

  16. A Direct inverse model to determine permeability fields from pressure and flow rate measurements

    NARCIS (Netherlands)

    Brouwer, G.K.; Fokker, P.A.; Wilschut, F.; Zijl, W.

    2008-01-01

    The determination of the permeability field from pressure and flow rate measurements in wells is a key problem in reservoir engineering. This paper presents a Double Constraint method for inverse modeling that is an example of direct inverse modeling. The method is used with a standard block-centere

  17. Damage of cellular material under simultaneous application of pressure and pulsed electric field

    CERN Document Server

    Bazhal, M I; Vorobev, E I

    2000-01-01

    Influence of pulsed electric field (PEF) simultaneous to pressure treatment on moisture expression from fine-cut cellular raw material has been investigated. Dependencies of specific conductivity $\\sigma$, liquid yield $Y$, instantaneous flow rate $v$ and qualitative juice characteristics at different modes of PEF treatment are discussed. Three main consolidation phases were observed in a case of mechanical expression. A unified approach is proposed for liquid yield data analysis allowing to reduce the data scattering caused by differences in the quality of samples. Simultaneous application of pressure and PEF treatment allows to reveal a passive form of electrical damage. Pressure provokes the damage of defected cells, enhances diffusion migration of moisture in porous cellular material and depresses the cell resealing processes. PEF application at a moment when a sample specific electrical conductivity reaches minimum and pressure achieves its constant value seemed to be the most optimal.

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

    Science.gov (United States)

    Uxa, Tomáš; Mida, Peter

    2017-04-01

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

  19. The Ties that Bind? Galactic Magnetic Fields and Ram Pressure Stripping

    CERN Document Server

    Tonnesen, Stephanie

    2014-01-01

    One process affecting gas-rich cluster galaxies is ram pressure stripping, i.e. the removal of galactic gas through direct interaction with the intracluster medium. Galactic magnetic fields may have an important impact on the stripping rate and tail structure. We run the first magnetohydrodynamic simulations of ram pressure stripping that include a galactic magnetic field, using 159 pc resolution throughout our entire domain in order to resolve mixing throughout the tail. We find very little difference in the total amount of gas removed from the unmagnetized and magnetized galaxies, although a magnetic field with a radial component will initially accelerate stripped gas more quickly. In general, we find that magnetic fields in the disk lead to slower velocities in the stripped gas near the disk and faster velocities farther from the disk. We also find that magnetic fields in the galactic gas lead to larger unmixed structures in the tail. Finally, we discuss whether ram pressure stripped tails can magnetize th...

  20. Decoding intravesical pressure from local field potentials in rat lumbosacral spinal cord

    Science.gov (United States)

    Im, Changkyun; Park, Hae Yong; Koh, Chin Su; Ryu, Sang Baek; Seo, In Seok; Kim, Yong Jung; Kim, Kyung Hwan; Shin, Hyung-Cheul

    2016-10-01

    Chronic monitoring of intravesical pressure is required to detect the onset of intravesical hypertension and the progression of a more severe condition. Recent reports demonstrate the bladder state can be monitored from the spiking activity of the dorsal root ganglia or lumbosacral spinal cord. However, one of the most serious challenges for these methods is the difficulty of sustained spike signal acquisition due to the high-electrode-location-sensitivity of spikes or neuro-degeneration. Alternatively, it has been demonstrated that local field potential recordings are less affected by encapsulation reactions or electrode location changes. Here, we hypothesized that local field potential (LFP) from the lumbosacral dorsal horn may provide information concerning the intravesical pressure. LFP and spike activities were simultaneously recorded from the lumbosacral spinal cord of anesthetized rats during bladder filling. The results show that the LFP activities carry significant information about intravesical pressure along with spiking activities. Importantly, the intravesical pressure is decoded from the power in high-frequency bands (83.9-256 Hz) with a substantial performance similar to that of the spike train decoding. These findings demonstrate that high-frequency LFP activity can be an alternative intravesical pressure monitoring signal, which could lead to a proper closed loop system for urinary control.

  1. Magnetic-field- and pressure-induced quantum phase transition in CsFeCl3 proved via magnetization measurements

    Science.gov (United States)

    Kurita, Nobuyuki; Tanaka, Hidekazu

    2016-09-01

    We have performed magnetization measurements of the gapped quantum magnet CsFeCl3 at temperatures (T ) down to 0.5 K at ambient pressure and down to 1.8 K at hydrostatic pressures (P ) of up to 1.5 GPa. The lower-field (H ) phase boundary of the field-induced ordered phase at ambient pressure is found to follow the power-law behavior expressed by the formula HN(T ) -Hc∝TNϕ . The application of pressure extends the phase boundary to both a lower field and higher temperature. Above the critical pressure Pc˜0.9 GPa, the transition field HN associated with the excitation gap becomes zero, and a signature of the magnetic phase transition is found in the T dependence of magnetization in a very low applied field. This suggests that CsFeCl3 exhibits a pressure-induced magnetic phase transition at Pc.

  2. GPS Radio Occultation: A Potential New Data Source for Improvement of Antarctic Pressure Field

    Institute of Scientific and Technical Information of China (English)

    Ge Sheng-jie; C. K. Shum; J. Wickert; Ch. Reigber

    2003-01-01

    Radio occultation technique, first demonstrated by the GPS/MET experiment in 1995[1], has the potential to provide improved spatial and temporal resolution in the probing of the Earth's neutral atmosphere, including pressure,temperature and water vapor profiles, in addition to traditional measurements (e.g.,radiosonde, spaceborne radiometers) and ground-based GPS networks for precipitable water vapor (PWV) measurements. This paper provides an overview of the radio occultation concept and retrieval procedure and current technical limitations including lower troposphere inhomogeneities, signal penetration, multipath, and water vapor ambiguity. The current limitations using atmospheric model pressure fields (ECMWF and NCEP) for the modeling of atmospheric mass load over Antarctica, for its separation from climate sensitive signals observed by gravity mapping satellite,GRACE, are quantified. Atmospheric pressure fields over Antarctica are poorly known and higher temporal variability of pressure causes an "aliasing" error in GRACE-observed climate-sensitive signals such as hydrology, mass balance and oceanic mass variations. In particular, comparison of ECMWF 6-hour data with the Automatic Weather Station (AWS) in Antarctica indicates mean differences of 5 hPa,and rms of 1.7 hPa, exceeding the accuracy requirement for GRACE. Aliasing effec tmanifests as high-frequency errors in GRACE-observed gravity signals and are more pronounced over Antarctica. The possibility of using current operating satellite(SAC-C, CHAMP and GRACE) occultation data to improve Antarctic surface pressure fields is proposed. Preliminary results indicate that in the absence of water vapor over Antarctica, retrieved CHAMP pressure profile agrees well with radiosonde data from Neumayer station, and that occultation signals reach near the surface.

  3. Wall Shear Stress, Wall Pressure and Near Wall Velocity Field Relationships in a Whirling Annular Seal

    Science.gov (United States)

    Morrison, Gerald L.; Winslow, Robert B.; Thames, H. Davis, III

    1996-01-01

    The mean and phase averaged pressure and wall shear stress distributions were measured on the stator wall of a 50% eccentric annular seal which was whirling in a circular orbit at the same speed as the shaft rotation. The shear stresses were measured using flush mounted hot-film probes. Four different operating conditions were considered consisting of Reynolds numbers of 12,000 and 24,000 and Taylor numbers of 3,300 and 6,600. At each of the operating conditions the axial distribution (from Z/L = -0.2 to 1.2) of the mean pressure, shear stress magnitude, and shear stress direction on the stator wall were measured. Also measured were the phase averaged pressure and shear stress. These data were combined to calculate the force distributions along the seal length. Integration of the force distributions result in the net forces and moments generated by the pressure and shear stresses. The flow field inside the seal operating at a Reynolds number of 24,000 and a Taylor number of 6,600 has been measured using a 3-D laser Doppler anemometer system. Phase averaged wall pressure and wall shear stress are presented along with phase averaged mean velocity and turbulence kinetic energy distributions located 0.16c from the stator wall where c is the seal clearance. The relationships between the velocity, turbulence, wall pressure and wall shear stress are very complex and do not follow simple bulk flow predictions.

  4. Pressure Buildup Analysis for Two-Phase Geothermal Wells: Application to the Baca Geothermal Field

    Science.gov (United States)

    Riney, T. D.; Garg, S. K.

    1985-03-01

    The recently published pressure transient analysis methods for two-phase geothermal wells are employed to analyze the pressure buildup data for several wells located in the Redondo Creek area of the Baca geothermal field in New Mexico. The downhole drilling information and pressure/temperature surveys are first interpreted to locate zones at which fluid enters the well bore from the formation and to estimate the initial reservoir temperature and pressure in these zones. All of the Baca wells considered here induced flashing in the formation upon production. Interpretation of the buildup data for each well considers well bore effects (e.g., phase change in the well bore fluid and location of the pressure sensor with respect to the permeable horizon) and the carbon dioxide content of the fluid and its effects on the phase behavior of the reservoir fluids and differentiates between the single- and two-phase portions of the pressure buildup data. Different straight-line approximations to the two portions (i.e., single- and two-phase) of the data on the Homer plot are used to obtain corresponding estimates for the single- and two-phase mobilities. Estimates for the formation permeability-thickness (kH) product are also given.

  5. Mechanics Evolution Characteristics Analysis of Pressure-arch in Fully-mechanized Mining Field

    Directory of Open Access Journals (Sweden)

    S.R. Wang

    2014-09-01

    Full Text Available Based on a practical engineering, the three-dimension computational model was built using FLAC3D under the fullymechanized mining condition. Considering four variation factors, such as the distance of mining advancing, the strength of the surrounding rock, the speed of mining advancing and the dip angle of the coal seam, the mechanics evolution characteristics of the pressure-arch were analyzed. The result showed that for the horizontal seam, the geometric shape of the pressure-arch varied from flat arch to round arch gradually and the height and thickness of the pressure-arch also increased; the maximum principal stress in the skewback also increased with the working face advancing. With the strength of the surrounding rock from soft to hard, the arch thickness reduced, and the arch loading decreased. To improve the mining speed can do some contributions to the stability of the pressure-arch in the mining field. With the increase of dip angle of the seam, the pressure-arch displayed an asymmetric shape, the vault was tilted and moved to the upward direction. At the same time, the thickness of the pressure-arch increased, and the stress concentration in the skewback tended to be further intensified.

  6. Behavior of antiferromagnetic MnCoSi in a magnetic field under pressure

    Energy Technology Data Exchange (ETDEWEB)

    Zavorotnev, Yu.D., E-mail: zavorotnev.yurii@gmail.com [Donetsk Institute for Physics and Engineering, NAS of Ukraine, 72 R. Luxemburg St., 83114 Donetsk (Ukraine); Medvedeva, L.I.; Todris, B.M.; Dvornikov, E.A. [Donetsk Institute for Physics and Engineering, NAS of Ukraine, 72 R. Luxemburg St., 83114 Donetsk (Ukraine); Popova, O.Yu. [Donetsk National Technical University, 58 Artema St., 83001 Donetsk (Ukraine)

    2011-11-15

    Experimental data on magnetization of the antiferromagnetic (AFM) polycrystalline samples in the temperature range of 20-300 K, for pressures of 2 kbar and in magnetic field of 300 kOe, are presented in the paper. In the fields of 250 kOe, the magnetization curve demonstrates a jump explained by exchange-interaction sign change. In the region of 50-70 kOe, on the differential susceptibility versus magnetic field curve, there is a break of the 2nd order corresponding to the anomalous behavior of the magnetization. The obtained results were processed on the basis of the phenomenological Landau theory. It is shown that the ferromagnetic vector occurrence is forced during the formation of AFM spiral structure. The behavior of thermodynamic potential factors has been determined. Three more anomalies have been revealed and explained by a jump-like magnetization change of the Co-subsystem. - Highlights: > MnCoSi alloy is studied under pressure of 2 kbar, at magnetic field of 300 kOe. > Temperature range was 20-300 K. > Pressure-dependent magnetization jump is due to sign change of exchange interaction. > Magnetization anomaly is conditioned by intersection of the lowest levels of Co ions. > Temperature extrema at magnetization are realized within the jump region.

  7. Frustrated antiferromagnet YbAgGe under magnetic fields and pressures

    Energy Technology Data Exchange (ETDEWEB)

    Kubo, Hirokazu; Umeo, Kazunori; Takabatake, Toshiro [ADSM, Hiroshima University, Higashi-Hiroshima 739-8530 (Japan); Katoh, Kenichi [Department of Applied Physics, National Defense Academy, Yokosuka 239-8686 (Japan); Ochiai, Akira, E-mail: khirokazu@hiroshima-u.ac.j [Department of Physics, Graduate School of Science, Tohoku University, Sendai 980-8578 (Japan)

    2010-01-15

    We present a detailed study of the field (B)- temperature (T) phase diagram under pressures (P) up to 2.7 GPa for the heavy-fermion antiferromagnet YbAgGe that crystallizes in the hexagonal ZrNiAl-type structure with a quasi-kagome lattice of Yb ions. This compound undergoes two magnetic transitions at T{sub M1} = 0.8 K and T{sub M2} = 0.65 K in zero field at ambient pressure. In the ground state, M(B) shows a metamagnetic transition at B{sub M} = 4.6 T for the easy magnetization direction B || a. This transition field decreases to 3.3 T as P is increased to 2.2 GPa. At 2.7 GPa, {rho}(B) exhibits successive transitions at 5.0, 6.0, 7.5, and 9.0 T. On the other hand, for the hard direction B || c, T{sub M} increases with applied field in the P range above 0.5 GPa. This increase of T{sub M}(B) is opposite to the decrease of T{sub M}(B) for a conventional antiferromagnetic phase. These findings suggest that the application of pressure releases in part the magnetic frustration in YbAgGe.

  8. Phase field simulations of plastic strain-induced phase transformations under high pressure and large shear

    Science.gov (United States)

    Javanbakht, Mahdi; Levitas, Valery I.

    2016-12-01

    Pressure and shear strain-induced phase transformations (PTs) in a nanograined bicrystal at the evolving dislocations pile-up have been studied utilizing a phase field approach (PFA). The complete system of PFA equations for coupled martensitic PT, dislocation evolution, and mechanics at large strains is presented and solved using the finite element method (FEM). The nucleation pressure for the high-pressure phase (HPP) under hydrostatic conditions near a single dislocation was determined to be 15.9 GPa. Under shear, a dislocation pile-up that appears in the left grain creates strong stress concentration near its tip and significantly increases the local thermodynamic driving force for PT, which causes nucleation of HPP even at zero pressure. At pressures of 1.59 and 5 GPa and shear, a major part of a grain transforms to HPP. When dislocations are considered in the transforming grain as well, they relax stresses and lead to a slightly smaller stationary HPP region than without dislocations. However, they strongly suppress nucleation of HPP and require larger shear. Unexpectedly, the stationary HPP morphology is governed by the simplest thermodynamic equilibrium conditions, which do not contain contributions from plasticity and surface energy. These equilibrium conditions are fulfilled either for the majority of points of phase interfaces or (approximately) in terms of stresses averaged over the HPP region or for the entire grain, despite the strong heterogeneity of stress fields. The major part of the driving force for PT in the stationary state is due to deviatoric stresses rather than pressure. While the least number of dislocations in a pile-up to nucleate HPP linearly decreases with increasing applied pressure, the least corresponding shear strain depends on pressure nonmonotonously. Surprisingly, the ratio of kinetic coefficients for PT and dislocations affect the stationary solution and the nanostructure. Consequently, there are multiple stationary solutions

  9. 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.

  10. Empirically based gamma-distributed random wall pressure field in silo

    DEFF Research Database (Denmark)

    Ditlevsen, Ove Dalager; Berntsen, Kasper Nikolaj

    1999-01-01

    Measurements show that silo wall pressures exhibit large fluctuations in time and space during discharge of the silo. This observation is important for the design of the silowall because spatial pressure variations may impose substantial bending moments in the silo wall that otherwise may be small...... or vanishing do to the carrying ability of the membrane forces in the silo wall. Information about the stochastic properties of this pressure variation cannot be obtained from any existing continuum model for the silo medium flowing within the confinement of the silo walls. Therefore the modeling must...... presently be tied to statistical analysis of the empirical evidence combined with simple mechanical rinciples. It is shown that an explicitely constructed gamma distribution type of field in equilibrium with itself fits well to themeasurements made in the Swedish Karpalund silo....

  11. Effect of high hydrostatic pressure, ultrasound and pulsed electric fields on milk composition and characteristics

    Directory of Open Access Journals (Sweden)

    Irena Jeličić

    2012-03-01

    Full Text Available High hydrostatic pressure, ultrasonication and pulsed eletrcic fields (PEF belong to novel food processing methods which are mostly implemented in combination with moderate temperatures and/ or in combination with each other in order to provide adequate microbiological quality with minimal losses of nutritional value. All of three mentioned methods have been intensively investigated for the purpose of inactivation and reduction of foodborne microorganisms present in milk and dairy products. However, a large number of scientific researches have been dedicated to investigation of impact of these methods on changes in constituents like milk fat, milk proteins and lactose as well as changes in mechanisms like renneting properties and coagulation of milk. The aim of this research was to give an overview of changes in milk constituents induced by high hydrostatic pressure, ultrasonification and pulsed electric field treatments as well as to suggest how these changes could improve conventional processes in the dairy industry.

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

    Science.gov (United States)

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

    2014-08-01

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

  13. Particle tracking velocimetry applied to estimate the pressure field around a Savonius turbine

    Science.gov (United States)

    Murai, Yuichi; Nakada, Taishi; Suzuki, Takao; Yamamoto, Fujio

    2007-08-01

    Particle tracking velocimetry (PTV) is applied to flows around a Savonius turbine. The velocity vector field measured with PTV is utilized to estimate the pressure field around the turbine, as well as to evaluate the torque performance. The main objective of the work is the establishment of the pressure estimation scheme required to discuss the turbine performance. First, the PTV data are interpolated on a regular grid with a fourth-order ellipsoidal differential equation to generate velocity vectors satisfying the third-order spatio-temporal continuity both in time and space. Second, the phase-averaged velocity vector information with respect to the turbine angle is substituted into three different types of pressure-estimating equations, i.e. the Poisson equation, the Navier-Stokes equation and the sub-grid scale model of turbulence. The results obtained based on the Navier-Stokes equation are compared with those based on the Poisson equation, and have shown several merits in employing the Navier-Stokes-based method for the PTV measurement. The method is applied to a rotating turbine with the tip-speed ratio of 0.5 to find the relationship between torque behaviour and flow structure in a phase-averaged sense. We have found that a flow attached to the convex surface of the blades induces low-pressure regions to drive the turbine, namely, the lift force helps the turbine blades to rotate even when the drag force is insufficient. Secondary mechanisms of torque generation are also discussed.

  14. Turbulent magnetic field amplification driven by cosmic-ray pressure gradients

    CERN Document Server

    Drury, Luke O'C

    2012-01-01

    Observations of non-thermal emission from several supernova remnants suggest that magnetic fields close to the blastwave are much stronger than would be naively expected from simple shock compression of the field permeating the interstellar medium (ISM). We present a simple model which is capable of achieving sufficient magnetic field amplification to explain the observations. We propose that the cosmic-ray pressure gradient acting on the inhomogeneous ISM upstream of the supernova blastwave induces strong turbulence upstream of the supernova blastwave. The turbulence is generated through the differential acceleration of the upstream ISM which occurs as a result of density inhomogeneities in the ISM. This turbulence then amplifies the pre-existing magnetic field. Numerical simulations are presented which demonstrate that amplification factors of 20 or more are easily achievable by this mechanism when reasonable parameters for the ISM and supernova blastwave are assumed. The length scale over which this amplif...

  15. Pressure-induced superconductivity in a ferromagnet, UGe sub 2 : resistivity measurements in a magnetic field

    CERN Document Server

    Kobayashi, T C; Tateiwa, N; Amaya, K; Haga, Y; Settai, R; Onuki, Y

    2002-01-01

    Electrical resistivity measurements in a magnetic field are carried out on UGe sub 2 which exhibits pressure-induced superconductivity. The superconductivity is observed from 1.06 to 1.44 GPa. In the temperature and field dependences of the resistivity at P > P sub C where the ferromagnetic ordering disappears, it is observed that the application of an external field along the a-axis increases the coefficient A of the Fermi-liquid behaviour (propor to AT sup 2) abruptly - corresponding to the metamagnetic transition. The characteristic enhancement of H sub C sub 2 is reconfirmed for H || a-axis. The upper critical field of H sub C sub 2 is anisotropic: H sub C sub 2 (T) exhibits positive curvature for H || b-axis and H || c-axis.

  16. Pressure Distribution Characters of Flow Field around High-Speed Train

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Based on incompressible viscous fluid Navier-Stokes equation and k-ε 2-equationsturbulent model, an investigation on 3D turbulent flow field around four kinds of train models has been made by finite element method. From the calculation, the pressure distribution characters of flow field around high-speed trains have been obtained. It is significant for strength design of the high-speed train body, for resisting wind design of the facilities beside the high-speed railways and for determining the aerodynamic force of induced air to the human body near the railways.

  17. The effect of electron thermal conduction on plasma pressure gradient during reconnection of magnetic field lines

    Energy Technology Data Exchange (ETDEWEB)

    Chu, T.K.

    1987-12-01

    The interplay of electron cross-field thermal conduction and the reconnection of magnetic field lines around an m = 1 magnetic island prior to a sawtooth crash can generate a large pressure gradient in a boundary layer adjacent to the reconnecting surface, leading to an enhanced gradient of poloidal beta to satisfy the threshold condition for ideal MHD modes. This narrow boundary layer and the short onset time of a sawtooth crash can be supported by fine-grained turbulent processes in a tokamak plasma. 11 refs.

  18. The Properties of Light Pressure Force with High Order in Laser Fields

    Institute of Scientific and Technical Information of China (English)

    陈险峰; 方建兴; 朱士群

    2002-01-01

    In this paper, the light pressure force in low and high intensity laser fields is derived. The exact numerical results of forces Fn∥(n=0,1,2,3,4,5,6…) through the matrix continued fraction method are presented. At low intensity field (G=1), the spatially averaged force F0∥ gives a cooling effect at the negative detuning. At high intensity (G=64), the effects of the forces with higher order (n≥2) appear and the contributes of the forces with odd or even order are opposite. It is great different from no high order force at low intensity.

  19. $Er^{3+}$ luminescence as a sensor of high pressure and strong external magnetic fields

    NARCIS (Netherlands)

    Valiente, R.; Millot, M.; Rodriguez, F.; Gonzalez, J.; Broto, J-M.; George, S.; Garcia-Revilla, S.; Romanyuk, Y.; Pollnau, M.

    2009-01-01

    In this paper, we present the preliminary results of the combined effect of high pressure (up to 7.5 GPa) and strong external magnetic fields (up to 28.5 T) on the photoluminescence (PL) properties of $Er^{3+}–Yb^{3+}$ co-doped single-crystal thin films of well-oriented $KY(WO_4)_2$ at low temperat

  20. THE EFFECT OF MAGNETIC FIELDS ON LOW FREQUENCY OSCILLATING NATURAL CONVECTION WITH PRESSURE GRADIENT

    Institute of Scientific and Technical Information of China (English)

    G.C. Sharma; Madhu Jain; Mahesh Chandra

    2003-01-01

    The oscillating natural convection in the presence of transverse magnetic field with time depending pressure gradient is studied. The analysis of the problem is carried out by assuming that the fluid is flowing in a parallel plate configuration. The emphasis is on low frequency oscillating convective flows induced by g-jitter associated with micro gravity because of their importance to the space processing materials. A general solution for an oscillating flow in the presence of transverse magnetic field is carried out. Some special cases of the oscillating flow and its response to an applied magnetic field are performed. It was observed that the behavior of oscillating free convective flows depends on frequency, amplitude of the driving buoyancy forces, temperature gradient, magnetic field and the electric conditions of the channel walls. In the absence of magnetic field, buoyancy force plays a predominant role in driving the oscillatory flow pattern, and velocity magnitude is also affected by temperature gradients. To suppress the oscillating flow external magnetic field can be used. It is also found that the reduction of the velocity is inversely proportional to the square of the applied magnetic field with conducting wall but directly proportional to the inverse of the magnetic field with insulating wall. Detailed calculations and computational results are also carried out to depict the real situation.

  1. Sonar-induced pressure fields in a post-mortem common dolphin.

    Science.gov (United States)

    Foote, Kenneth G; Hastings, Mardi C; Ketten, Darlene R; Lin, Ying-Tsong; Reidenberg, Joy S; Rye, Kent

    2012-02-01

    Potential physical effects of sonar transmissions on marine mammals were investigated by measuring pressure fields induced in a 119-kg, 211-cm-long, young adult male common dolphin (Delphinus delphis) cadaver. The specimen was instrumented with tourmaline acoustic pressure gauges used as receiving sensors. Gauge implantation near critical tissues was guided by intraoperative, high-resolution, computerized tomography (CT) scanning. Instrumented structures included the melon, nares, ear, thoracic wall, lungs, epaxial muscle, and lower abdomen. The specimen was suspended from a frame equipped with a standard 50.8-mm-diameter spherical transducer used as the acoustic source and additional receiving sensors to monitor the transmitted and external, scattered field. Following immersion, the transducer transmitted pulsed sinusoidal signals at 5, 7, and 10 kHz. Quantitative internal pressure fields are reported for all cases except those in which the gauge failed or no received signal was detected. A full necropsy was performed immediately after the experiment to examine instrumented areas and all major organs. No lesions attributable to acoustic transmissions were found, consistent with the low source level and source-receiver distances.

  2. FDTD simulation of finite-amplitude pressure and temperature fields for biomedical ultrasound.

    Science.gov (United States)

    Hallaj, I M; Cleveland, R O

    1999-05-01

    Full wave simulations provide a valuable tool for studying the spatial and temporal nature of an acoustic field. One method for producing such simulations is the finite-difference time-domain (FDTD) method. This method uses discrete differences to approximate derivatives in the governing partial differential equations. We used the FDTD method to model the propagation of finite-amplitude sound in a homogeneous thermoviscous fluid. The calculated acoustic pressure field was then used to compute the transient temperature rise in the fluid; the heating results from absorption of acoustic energy by the fluid. As an example, the transient temperature field was calculated in biological tissue in response to a pulse of focused ultrasound. Enhanced heating of the tissue from finite-amplitude effects was observed. The excess heating was attributed to the nonlinear generation of higher-frequency harmonics which are absorbed more readily than the fundamental. The effect of nonlinear distortion on temperature rise in tissue was observed to range from negligible at 1 MPa source pressure to an 80% increase in temperature elevation at 10 MPa source pressure.

  3. Planar Pressure Field Determination in the Initial Merging Zone of an Annular Swirling Jet Based on Stereo-PIV Measurements.

    Science.gov (United States)

    Vanierschot, Maarten; Van den Bulck, Eric

    2008-11-28

    In this paper the static pressure field of an annular swirling jet is measured indirectly using stereo-PIV measurements. The pressure field is obtained from numerically solving the Poisson equation, taken into account the axisymmetry of the flow. At the boundaries no assumptions are made and the exact boundary conditions are applied. Since all source terms can be measured using stereo-PIV and the boundary conditions are exact, no assumptions other than axisymmetry had to be made in the calculation of the pressure field. The advantage of this method of indirect pressure measurement is its high spatial resolution compared to the traditional pitot probes. Moreover this method is non-intrusive while the insertion of a pitot tube disturbs the flow. It is shown that the annular swirling flow can be divided into three regimes: a low, an intermediate and a high swirling regime. The pressure field of the low swirling regime is the superposition of the pressure field of the non-swirling jet and a swirl induced pressure field due to the centrifugal forces of the rotating jet. As the swirl increases, the swirl induced pressure field becomes dominant and for the intermediate and high swirling regimes, the simple radial equilibrium equation holds.

  4. Magnetic field-induced gluonic (inverse) catalysis and pressure (an)isotropy in QCD

    CERN Document Server

    Bali, G S; Endrodi, G; Gruber, F; Schaefer, A

    2013-01-01

    We study the influence of strong external magnetic fields on gluonic and fermionic observables in the QCD vacuum at zero and nonzero temperatures, via lattice simulations with N_f=1+1+1 staggered quarks of physical masses. The gluonic action density is found to undergo magnetic catalysis at low temperatures and inverse magnetic catalysis near and above the transition temperature, similar to the quark condensate. Moreover, the gluonic action develops an anisotropy: the chromo-magnetic field parallel to the external field is enhanced, while the chromo-electric field in this direction is suppressed. We demonstrate that the same hierarchy is obtained using the Euler-Heisenberg effective action. Conversely, the topological charge density correlator does not reveal a significant anisotropy up to magnetic fields eB~1 GeV^2. Furthermore, we show that the pressure remains isotropic even for nonzero magnetic fields, if it is defined through a compression of the system at fixed external field. In contrast, if the flux o...

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

    Science.gov (United States)

    Nieuwendam, Alexandre; Ramos, Miguel; Vieira, Gonçalo

    2015-04-01

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

  6. Magnetic Pressure as a Scalar Representation of Field Effects in Magnetic Suspensions

    Science.gov (United States)

    Zborowski, Maciej; Moore, Lee R.; Williams, P. Stephen; Chalmers, Jeffrey J.

    2014-01-01

    Magnetic microsphere suspensions undergo complex motion when exposed to finite sources of the magnetic field, such as small permanent magnets. The computational complexity is compounded by a difficulty in choosing a suitable choice of visualization tools because this often requires using the magnetic force vector field in three dimensions. Here we present a potentially simpler approach by using the magnetic pressure. It is a scalar quantity, pm = B2/2μ0, and its usefulness has been already demonstrated in applications to magnetohydrodynamics and ferrohydrodynamics (where B is the applied field and μ0 = 4π×10−7 T.m/A). The equilibrium distribution of the magnetic bead plug in aqueous suspension is calculated as an isosurface of the magnitude of the magnetic pressure pm = const, in the field of two permanent magnet blocks calculated from closed formulas. The geometry was adapted from a publication on the magnetic bead suspensions in microsystems and the predicted bead plug distribution is shown to agree remarkably well with the experiment. PMID:25382882

  7. FFT integration of instantaneous 3D pressure gradient fields measured by Lagrangian particle tracking in turbulent flows

    Science.gov (United States)

    Huhn, F.; Schanz, D.; Gesemann, S.; Schröder, A.

    2016-09-01

    Pressure gradient fields in unsteady flows can be estimated through flow measurements of the material acceleration in the fluid and the assumption of the governing momentum equation. In order to derive pressure from its gradient, almost exclusively two numerical methods have been used to spatially integrate the pressure gradient until now: first, direct path integration in the spatial domain, and second, the solution of the Poisson equation for pressure. Instead, we propose an alternative third method that integrates the pressure gradient field in Fourier space. Using a FFT function, the method is fast and easy to implement in programming languages for scientific computing. We demonstrate the accuracy of the integration scheme on a synthetic pressure field and apply it to an experimental example based on time-resolved material acceleration data from high-resolution Lagrangian particle tracking with the Shake-The-Box method.

  8. Efficacy of pulsed electromagnetic field therapy in healing of pressure ulcers: A randomized control trial

    Directory of Open Access Journals (Sweden)

    Gupta Anupam

    2009-12-01

    Full Text Available Background : Pressure ulcers are one of the most common complications in health care settings. Still there are no optimal protocols to manage the pressure ulcers. Aim : To assess the effectiveness of pulsed electromagnetic field therapy (PEMF in healing of pressure ulcers in patients with neurological disorders. Design : Randomized double blind control trial. Setting : Neurological rehabilitation department in a university research hospital. Participants : Twelve patients (M:F, 9:3 having neurological disorders, with age between 12-50 years (mean 30.16611.32 yrs and 24 pressure ulcers. Intervention : Six patients with 13 ulcers received PEMF therapy and the remaining 6 patients with 11 ulcers received sham treatment, for 30 sessions (45 minutes each using the equipment ′Pulsatron′. The frequency of PEMF was set at 1 Hz with sine waves and current intensity of 30 mili ampere. Whole body exposure was given in both the groups. Outcome Measures : Bates-Jensen wound assessment tool (BJWAT score was used as main outcome measure and scores at the end of session were compared with initial scores and analyzed. Similarly National Pressure Ulcer Advisory Panel (NPUAP scores were compared and analyzed as secondary outcome measure. Results : Thirteen ulcers were in stage IV and 11 were in stage III at the start of the study. Significant healing of ulcers was noted, BJWAT scores, in both the treatment and sham groups (P < 0.001 and 0.003 respectively at the completion of the study. However, when comparing between the groups, healing was not significant (P = 0.361. Similarly trend was noted with NPUAP scores with no significant difference between the treatment and sham groups (P = 0.649 at the completion of study. Conclusions : No significant difference in pressure ulcer healing was observed between PEMF treatment and sham group in this study.

  9. Pressure and Compressibility of Conformal Field Theories from the AdS/CFT Correspondence

    Directory of Open Access Journals (Sweden)

    Brian P. Dolan

    2016-05-01

    Full Text Available The equation of state associated with N = 4 supersymmetric Yang–Mills in four dimensions, for S U ( N in the large N limit, is investigated using the AdS/CFT correspondence. An asymptotically AdS black-hole on the gravity side provides a thermal background for the Yang–Mills theory on the boundary in which the cosmological constant is equivalent to a volume. The thermodynamic variable conjugate to the cosmological constant is a pressure, and the P - V diagram of the quark-gluon plasma is studied. It is known that there is a critical point where the heat capacity diverges, and this is reflected in the isothermal compressibility. Critical exponents are derived and found to be mean field in the large N limit. The same analysis applied to three- and six-dimensional conformal field theories again yields mean field exponents associated with the compressibility at the critical point.

  10. Pressure, temperature, and electric field dependence of phase transformations in niobium modified 95/5 lead zirconate titanate

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Wen D.; Carlos Valadez, J.; Gallagher, John A.; Jo, Hwan R.; Lynch, Christopher S., E-mail: cslynch@seas.ucla.edu [Department of Mechanical and Aerospace Engineering, The University of California, Los Angeles, 420 Westwood Plaza, Los Angeles, California 90095 (United States); Sahul, Raffi; Hackenberger, Wes [TRS Technologies, 2820 East College Avenue, State College, Pennsylvania 16801 (United States)

    2015-06-28

    Ceramic niobium modified 95/5 lead zirconate-lead titanate (PZT) undergoes a pressure induced ferroelectric to antiferroelectric phase transformation accompanied by an elimination of polarization and a volume reduction. Electric field and temperature drive the reverse transformation from the antiferroelectric to ferroelectric phase. The phase transformation was monitored under pressure, temperature, and electric field loading. Pressures and temperatures were varied in discrete steps from 0 MPa to 500 MPa and 25 °C to 125 °C, respectively. Cyclic bipolar electric fields were applied with peak amplitudes of up to 6 MV m{sup −1} at each pressure and temperature combination. The resulting electric displacement–electric field hysteresis loops were open “D” shaped at low pressure, characteristic of soft ferroelectric PZT. Just below the phase transformation pressure, the hysteresis loops took on an “S” shape, which split into a double hysteresis loop just above the phase transformation pressure. Far above the phase transformation pressure, when the applied electric field is insufficient to drive an antiferroelectric to ferroelectric phase transformation, the hysteresis loops collapse to linear dielectric behavior. Phase stability maps were generated from the experimental data at each of the temperature steps and used to form a three dimensional pressure–temperature–electric field phase diagram.

  11. The Effects of Magnetic Fields on the Dynamics of Radiation Pressure-dominated Massive Star Envelopes

    Science.gov (United States)

    Jiang, Yan-Fei; Cantiello, Matteo; Bildsten, Lars; Quataert, Eliot; Blaes, Omer

    2017-07-01

    We use three-dimensional radiation magnetohydrodynamic simulations to study the effects of magnetic fields on the energy transport and structure of radiation pressure-dominated main sequence massive star envelopes at the region of the iron opacity peak. We focus on the regime where the local thermal timescale is shorter than the dynamical timescale, corresponding to inefficient convective energy transport. We begin with initially weak magnetic fields relative to the thermal pressure, from 100 to 1000 G in differing geometries. The unstable density inversion amplifies the magnetic field, increasing the magnetic energy density to values close to equipartition with the turbulent kinetic energy density. By providing pressure support, the magnetic field’s presence significantly increases the density fluctuations in the turbulent envelope, thereby enhancing the radiative energy transport by allowing photons to diffuse out through low-density regions. Magnetic buoyancy brings small-scale magnetic fields to the photosphere and increases the vertical energy transport, with the energy advection velocity proportional to the Alfvén velocity, although in all cases we study, photon diffusion still dominates the energy transport. The increased radiative and advective energy transport causes the stellar envelope to shrink by several scale heights. We also find larger turbulent velocity fluctuations compared with the purely hydrodynamic case, reaching ≈ 100 {{{km}}{{s}}}-1 at the stellar photosphere. The photosphere also shows vertical oscillations with similar averaged velocities and periods of a few hours. The increased turbulent velocity and oscillations will have strong impacts on the line broadening and periodic signals in massive stars.

  12. The Flying Spaghetti Monster: Impact of magnetic fields on ram pressure stripping in disk galaxies

    CERN Document Server

    Ruszkowski, M; Lee, D; Shin, M -S

    2012-01-01

    Ram pressure stripping can remove significant amounts of gas from galaxies in clusters, and thus has a large impact on the evolution of cluster galaxies. Recent observations have shown that key properties of ram-pressure stripped tails of galaxies, such as their width and structure, are in conflict with predictions by simulations. To increase the realism of existing simulations, we simulated for the first time a disk galaxy exposed face-on to a uniformly magnetized wind including radiative cooling and self-gravity of the gas. We find that magnetic fields have a strong effect on the morphology of the gas in the tail of the galaxy. While in the purely hydrodynamical case the tail is very clumpy, the MHD case shows very filamentary structures in the tail. The filaments can be strongly supported by magnetic pressure and, wherever this is the case, the magnetic fields vectors tend to be aligned with the filaments. Interestingly, we observe the formation of two dominant magnetized density tails behind the galaxy re...

  13. Validation of the Cooray-Rubinstein (C-R) formula for a rough ground surface by using three-dimensional (3-D) FDTD

    Science.gov (United States)

    Li, Dongshuai; Zhang, Qilin; Liu, Tao; Wang, Zhenhui

    2013-11-01

    this paper, we have extended the Cooray-Rubinstein (C-R) approximate formula into the fractal rough ground surface and then validate its accuracy by using three-dimensional (3-D) finite-difference time-domain (FDTD) method at distances of 50 m and 100 m from the lightning channel. The results show that the extended C-R formula has an accepted accuracy for predicting the lightning-radiated horizontal electric field above the fractal rough and conducting ground, and its accuracy increases a little better with the higher of the earth conductivity. For instance, when the conductivity of the rough ground is 0.1 S/m, the error of the peak value predicted by the extended C-R formula is less than about 2.3%, while its error is less than about 6.7% for the conductivity of 0.01 S/m. The rough ground has much effect on the lightning horizontal field, and the initial peak value of the horizontal field obviously decreases with the increase of the root-mean-square height of the rough ground at early times (within several microseconds of the beginning of return stroke).

  14. Comparison of electrohydraulic lithotripters with rigid and pressure-release ellipsoidal reflectors. II. Cavitation fields.

    Science.gov (United States)

    Bailey, M R; Blackstock, D T; Cleveland, R O; Crum, L A

    1999-08-01

    Dramatically different cavitation was produced by two separate acoustic pulses that had different shapes but similar duration, frequency content, and peak positive and negative pressure. Both pulses were produced by a Dornier HM-3 style lithotripter: one pulse when the ellipsoidal reflector was rigid, the other when the reflector was pressure release. The cavitation, or bubble action, generated by the conventional rigid-reflector pulse was nearly 50 times longer lived and 3-13 times stronger than that produced by the pressure-release-reflector pulse. Cavitation durations measured by passive acoustic detection and high-speed video agreed with calculations based on the Gilmore equation. Cavitation intensity, or destructive potential, was judged (1) experimentally by the size of pits in aluminum foil detectors and (2) numerically by the calculated amplitude of the shock wave emitted by a collapsing bubble. The results indicate that the trailing positive spike in the pressure-release-reflector waveform stifles bubble growth and mitigates the collapse, whereas the trough after the positive spike in the rigid-reflector waveform triggers inertially driven growth and collapse. The two reflectors therefore provide a tool to compare effects in weakly and strongly cavitating fields and thereby help assess cavitation's role in lithotripsy.

  15. Pressure-induced Paschen-Back effect of R-lines in alexandrite under high magnetic field

    Science.gov (United States)

    Kuroda, Noritaka; Kanda, Hiroyuki; Kido, Giyuu; Takeda, Masayasu; Nishina, Yuichiro; Nakagawa, Yasuaki

    1992-06-01

    Magneto-luminescence of R-lines has been studied in alexandrite subjected to quasi-hydrostatic pressures near 8 GPa at 77 K. In contrast to the previous experiment under low pressures, the Zeeman spectrum exhibits Paschen-Back behavior if a magnetic field up to 15 T is applied parallel to the b- and c-axes of the crystal. This phenomenon reflects that the transverse moment of spins of the 2E term of Cr(3+) ions is significantly reduced by pressure. Pressure strengthens the Ising character of the spins by elevating axial symmetry of the crystal field.

  16. The pressure field in the liquid column in the tube-arrest method

    Institute of Scientific and Technical Information of China (English)

    Ying Chong-Fu; Li Chao; Xu De-Long; Deng Jing-Jun

    2008-01-01

    We have been using the method of tube-arrest as a means of producing transient single cavitation bubble. In the present paper we seek to comprehend the mechanism of production and inquire into the structure of the ab initio pressure field in the arrested liquid column. The generated pressure wave is shown by combining the theoretical analysis with the experimental observation to be a slightly varied version of water hammer. With relatively clean liquid, the magnitude of the tension peak generating the TSB is likely to reach of several millions Pa. It is also shown that the so generated cavitation bubble originating from the gas-containing bulk liquid is in 'violent' motion.

  17. Ocean-bottom Pressure Signals as Potential Identifiers of Tsunami Earthquakes in the Near Field

    Science.gov (United States)

    Salaree, A.; Okal, E. A.

    2015-12-01

    The real-time detection of "tsunami earthquakes" remains a challenge, especially in the near field. These events are characterized by an anomalously slow seismic rupture, with their true long-period seismic moment, and hence, tsunami potential, deceptively concealed from short-period waves and in particular felt accelerations. In the context of the deployment of long-period ocean-bottom sensors in epicentral areas, we explore simple but robust ways to quantify source parameters which could potentially lead to the real-time identification of tsunami earthquakes in the near field. We use records of 2011 Tohoku aftershocks on the JAMSTEC stations deployed off the coast of Japan in the wake of the mainshock. Because seismic phases are not resolvable at short distances, we simply consider an integrated measurement Ω of the square of pressure variations, sharing the philosophy of Boatwright and Choy's (1986) seismic energy, and compare this parameter, scaled to seismic moment, with other discriminants, such as Newman and Okal's (1998) energy-to-moment ratio, Θ, Okal et al.'s (2002) T-wave parameter Γ, or Okal's (2013) parameter Φ combining (in the far field) body-wave duration and energy. We also consider the duration of the pressure signal, and examine its relation to Ω.

  18. A field-emission pressure sensor of nano-crystalline silicon film

    Institute of Scientific and Technical Information of China (English)

    廖波; 韩建保

    2001-01-01

    The prototype of a field-emission pressure sensor with a novel structure based on the quantum tunnel effect is designed and manufactured, where a cathode emitter array is fabricated on the same silicon plate as the sensible film. For an integrated structure, not only the alignment and vacuum bonding between the anode and cathode are easy to be realized, but also a fine sensibility is guaranteed. For example, the measured current density emitted from the effective area of the sensor can reach 53.5 A/m2 when the exterior electric field is 5.6 x 105 V/m. Furthermore, it is demonstrated by finite element method simulation that the reduction in sensor sensitivity caused by emitters on the sensible film is negligible. The difference between the maximum deflections of the sensible films with and without emitters under specified pressure is less than 0.4 %. Therefore, it can be concluded that the novel field-emission sensor structure is reasonable.

  19. Pressure distribution in an electrical conducting fluid in spherical form in the presence of crossed electrical and magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Shchelukhin, E.M.; Tsarevskaya, I.I.; Bruskii, V.P.

    1977-01-01

    An examination is made of electromagnetic forces in an isotropic fluid having a spherical form with non-conducting walls in the presence of crossed electrical and magnetic fields. The problem was solved on the assumption that the fluid is in a quiescent state but that the magnetic field is uniform. Computations were made of static pressure distribution and the scalar potential of an electromagnetic field in a fluid. Experimental data are presented on the measurement of static pressure distributions which agree well with the theoretical calculations. The obtained results may be used for engineering estimates of pressure in technological MHD apparatus.

  20. Pressure driven tearing and interchange modes in the reversed field pinch

    Science.gov (United States)

    Paccagnella, R.

    2013-01-01

    In this work, the magneto-hydro-dynamic stability of pressure driven modes in the reversed field pinch has been analyzed. It is shown that at low and intermediate β's, i.e., typically for values below 20-25%, the tearing parity is dominant, while only at very high β, well above the achieved experimental values, at least part of the modes are converted to ideal interchange instabilities. Before their transition to ideal instabilities, according to their Lundquist number scaling, they can be classified as resistive-g modes.

  1. A sound field separation technique based on measurements with pressure-velocity probes

    DEFF Research Database (Denmark)

    Zhang, Yong-Bin; Chen, Xin-Zhao; Jacobsen, Finn

    2009-01-01

    It has recently been shown that statistically optimized near field acoustic holography based on measurement with an array of pressure-velocity transducers makes it possible to distinguish between sources on the two sides of the array and thus suppress the influence of a disturbing source [F....... Jacobsen and V. Jaud, J. Acoust. Soc. Am. 121, 1550-1558 (2007)]. However, the suggested technique uses a transfer matrix optimized for the source under test and may be expected to perform less well when the disturbing source is not placed symmetrically on the other side of the array, and this will usually...

  2. Spreading and atomization of droplets on a vibrating surface in a standing pressure field

    Science.gov (United States)

    Deepu, P.; Basu, Saptarshi; Saha, Abhishek; Kumar, Ranganathan

    2012-10-01

    We report the first observation and analytical model of deformation and spreading of droplets on a vibrating surface under the influence of an ultrasonic standing pressure field. The standing wave allows the droplet to spread, and the spreading rate varies inversely with viscosity. In low viscosity droplets, the synergistic effect of radial acoustic force and the transducer surface acceleration also leads to capillary waves. These unstable capillary modes grow to cause ultimate disintegration into daughter droplets. We find that using nanosuspensions, spreading and disintegration can be prevented by suppressing the development of capillary modes and subsequent break-up.

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

    Directory of Open Access Journals (Sweden)

    Lei Jiang

    2013-01-01

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

  4. Regional subsidence modelling in Murcia city (SE Spain using 1-D vertical finite element analysis and 2-D interpolation of ground surface displacements

    Directory of Open Access Journals (Sweden)

    S. Tessitore

    2015-11-01

    Full Text Available Subsidence is a hazard that may have natural or anthropogenic origin causing important economic losses. The area of Murcia city (SE Spain has been affected by subsidence due to groundwater overexploitation since the year 1992. The main observed historical piezometric level declines occurred in the periods 1982–1984, 1992–1995 and 2004–2008 and showed a close correlation with the temporal evolution of ground displacements. Since 2008, the pressure recovery in the aquifer has led to an uplift of the ground surface that has been detected by the extensometers. In the present work an elastic hydro-mechanical finite element code has been used to compute the subsidence time series for 24 geotechnical boreholes, prescribing the measured groundwater table evolution. The achieved results have been compared with the displacements estimated through an advanced DInSAR technique and measured by the extensometers. These spatio-temporal comparisons have showed that, in spite of the limited geomechanical data available, the model has turned out to satisfactorily reproduce the subsidence phenomenon affecting Murcia City. The model will allow the prediction of future induced deformations and the consequences of any piezometric level variation in the study area.

  5. Field-Induced CDW Phases in a Quasi-One-Dimensional Organic Conductor, HMTSF-TCNQ Under Pressure of 1 GPa in Magnetic Field of 31 T

    Science.gov (United States)

    Murata, K.; Kang, W.; Masuda, K.; Fukumoto, Y.; Graf, D.; Kiswandhi, A.; Choi, E. S.; Brooks, J. S.; Sasaki, T.; Yokogawa, K.; Yoshino, H.; Kato, R.

    2013-03-01

    HMTSF-TCNQ is a quasi-one-dimensional organic conductor which undergoes CDW(charge density wave) transition at 30 K at ambient pressure, where HMTSF-TCNQ is hexamethylenetetraselena fulvalene-tetracyano quino dimethane. This CDW is suppressed by the pressure of 1 GPa. At this pressure, we found field-induced successive hysteretic transitions in magnetoresistance. This reminds us of the successive field-induced SDW (spin density wave) phases in TMTSF2X salts. However, the field range of interest is 2-3 times higher than that of TMTSF2X salts. Therefore, we need really high field to examine these properties. It is very likely that the field induced phases are of field induced CDW (FICDW), where quantum Hall effect and many interesting phenomena are expected like in the case of FISDW. Together with the magnetoresistance study up to the field of 31 Tesla and at temperatures down to 0.4 K in various magnetic field angles respective to the crystal axes, we examined the angular dependence of magnetoresistance oscillations(AMRO). It turned out that AMRO demonstrates clearly the occurrence of field-induced phase rather than the magneto-resistance by field sweep. Since the Hall resistance, R xy in the field-induced phases showed stepwise plateau structure against the field sweep, and its strength was in the order of magnitude of h/ e 2 per molecular sheet, the Hall effect is very suggestive of quantum Hall effect.

  6. Application of nano-crystalline silicon film in the fabrication of field-emission pressure sensor

    Institute of Scientific and Technical Information of China (English)

    廖波; 陈旻; 孔德文; 张大成; 李婷

    2003-01-01

    A kind of filed-emission array pressure sensor is designed based on the quantum tunnel effect. The nano-crystalline silicon film is prepared by chemical vapor deposition (CVD) method, with the grain dimension and thickness of the film 3-9 nm and 30-40 nm, respectively. The nano-crystal- line silicon film is introduced into the cathode cones of the sensor, functioning as the essential emission part. The silicon nano phase is analyzed by HREM and TED, the microstructure of the single emitter and emitters array is inspected by SEM, and the field emission characteristics of the device are studied by an HP4145B transistor tester. The experimental results show that the measured current density emitted from the effective area of the sensor can reach 53.5 A/m2 when the exterior electric field is 5.6×105 V/m.

  7. Phase Field Theory and Analysis of Pressure-Shear Induced Amorphization and Failure in Boron Carbide Ceramic

    Science.gov (United States)

    2014-08-01

    Phase Field Theory and Analysis of Pressure-Shear Induced Amorphization and Failure in Boron Carbide Ceramic by John D Clayton ARL-RP...Pressure-Shear Induced Amorphization and Failure in Boron Carbide Ceramic John D Clayton Weapons and Materials Research Directorate, ARL...and Analysis of Pressure-Shear Induced Amorphization and Failure in Boron Carbide Ceramic 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM

  8. A synthesis pattern of acoustic field produced by phased array based on the direct weighting of the controlled acoustic pressure

    Institute of Scientific and Technical Information of China (English)

    HU Jiwen; QIAN Shengyou; DING Yajun

    2012-01-01

    To optimize the acoustic field produced by phased array effectively and quickly, the pseudo-inverse method proposed previously is simplified. An approximate weight formula of sound pressure using a method of compensation to the amplitude and phase of the controlled sound pressure was presented. A multiple-focus field patterns based on the pseudo-inverse matrix algorithm can be obtained by presetting the value of the controlled sound pressure. A phased array comprised of 16 x 16 square elements is used for numerical simulation. The results show that the acoustic energy can be effectively deposited at the desired points, and the acoustic field can be synthesized quickly using the direct weight formula of the sound pressure. This study may offer an effective way for controlling the distribution of acoustic field in ultrasound hyperthermia.

  9. Zero-field magnetism in Nd-doped CeRhIn5 under pressure

    Science.gov (United States)

    Rosa, Priscila; Oostra, Aaron; Luo, Yongkang; Wakeham, Nicholas; Ronning, Filip; Bauer, Eric; Fisk, Zachary; Thompson, Joe

    Unconventional superconductivity is often found in heavy fermion compounds close to a magnetic instability. Although magnetism and superconductivity may coexist when TN >Tc , evidence for magnetism is usually suddenly lost when TN pressure by means of electrical resistivity and AC calorimetry measurements. Our results show that, even at zero applied magnetic field, Nd substitution unveils a hidden magnetic instability below the superconducting dome. We examine the similarities and differences between our results and those on Nd-doped CeCoIn5 as well as pure CeRhIn5 under applied field and pressure. We discuss our results in light of recent calculations that include d-wave superconductivity and underlying magnetic correlations. Work at Los Alamos was performed under the auspices of the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Science and Engineering. P. F. S. Rosa acknowledges a Director's Postdoctoral Fellowship through the LDRD program.

  10. A tomographic visualization of electric discharge sound fields in atmospheric pressure plasma using laser diffraction

    Science.gov (United States)

    Nakamiya, Toshiyuki; Mitsugi, Fumiaki; Iwasaki, Yoichiro; Ikegami, Tomoaki; Tsuda, Ryoichi; Sonoda, Yoshito; Danuta Stryczewska, Henryka

    2013-02-01

    The phase modulation of transparent gas can be detected using Fraunhofer diffraction technique, which we call optical wave microphone (OWM). The OWM is suitable for the detection of sonic wave from audible sound to ultrasonic wave. Because this technique has no influence on sound field or electric field during the measurement, we have applied it to the sound detection for the electric discharges. There is almost no research paper that uses the discharge sound to examine the electrical discharge phenomenon. Two-dimensional visualization of the sound field using the OWM is also possible when the computerized tomography (CT) is combined. In this work, coplanar dielectric barrier discharge sin different gases of Ar, N2, He were characterized via the OWM as well as applied voltage and discharge current. This is the first report to investigate the influence of the type of the atmospheric gas on the two-dimensional sound field distribution for the coplanar dielectric barrier discharge using the OWM with CT. Contribution to the Topical Issue "13th International Symposium on High Pressure Low Temperature Plasma Chemistry (Hakone XIII)", Edited by Nicolas Gherardi, Henryca Danuta Stryczewska and Yvan Ségui.

  11. Electric field development in γ-mode radiofrequency atmospheric pressure glow discharge in helium

    Science.gov (United States)

    Navrátil, Zdeněk; Josepson, Raavo; Cvetanović, Nikola; Obradović, Bratislav; Dvořák, Pavel

    2016-06-01

    Time development of electric field strength during radio-frequency sheath formation was measured using Stark polarization spectroscopy in a helium γ-mode radio-frequency (RF, 13.56 MHz) atmospheric pressure glow discharge at high current density (3 A cm-2). A method of time-correlated single photon counting was applied to record the temporal development of spectral profile of He I 492.2 nm line with a sub-nanosecond temporal resolution. By fitting the measured profile of the line with a combination of pseudo-Voigt profiles for forbidden (2 1P-4 1F) and allowed (2 1P-4 1D) helium lines, instantaneous electric fields up to 32 kV cm-1 were measured in the RF sheath. The measured electric field is in agreement with the spatially averaged value of 40 kV cm-1 estimated from homogeneous charge density RF sheath model. The observed rectangular waveform of the electric field time development is attributed to increased sheath conductivity by the strong electron avalanches occurring in the γ-mode sheath at high current densities.

  12. Laser Anemometer Measurements of the Flow Field in a 4:1 Pressure Ratio Centrifugal Impeller

    Science.gov (United States)

    Skoch, G. J.; Prahst, P. S.; Wernet, M. P.; Wood, J. R.; Strazisar, A. J.

    1997-01-01

    A laser-doppler anemometer was used to obtain flow-field velocity measurements in a 4:1 pressure ratio, 4.54 kg/s (10 lbm/s), centrifugal impeller, with splitter blades and backsweep, which was configured with a vaneless diffuser. Measured through-flow velocities are reported for ten quasi-orthogonal survey planes at locations ranging from 1% to 99% of main blade chord. Measured through-flow velocities are compared to those predicted by a 3-D viscous steady flow analysis (Dawes) code. The measurements show the development and progression through the impeller and vaneless diffuser of a through-flow velocity deficit which results from the tip clearance flow and accumulation of low momentum fluid centrifuged from the blade and hub surfaces. Flow traces from the CFD analysis show the origin of this deficit which begins to grow in the inlet region of the impeller where it is first detected near the suction surface side of the passage. It then moves toward the pressure side of the channel, due to the movement of tip clearance flow across the impeller passage, where it is cut by the splitter blade leading edge. As blade loading increases toward the rear of the channel the deficit region is driven back toward the suction surface by the cross-passage pressure gradient. There is no evidence of a large wake region that might result from flow separation and the impeller efficiency is relatively high. The flow field in this impeller is quite similar to that documented previously by NASA Lewis in a large low-speed backswept impeller.

  13. Comprehensive database of wellbore temperatures and drilling mud weight pressures by depth for Judge Digby field, Louisiana

    Science.gov (United States)

    Burke, Lauri

    2010-01-01

    This document serves as the repository for the unprocessed data used in the investigation of temperature and overpressure relations within the deep Tuscaloosa Formation in Judge Digby field. It is a compilation of all the publicly accessible wellbore temperature and pressure data for Judge Digby field, a prolific natural gas field producing from the Upper Cretaceous lower part of the Tuscaloosa Formation in the Gulf Coast region. This natural gas field is in Pointe Coupee Parish in the southern part of onshore Louisiana.

  14. Efficiency of Magnetic Field Treatment on Pressure Sores in Bedridden Patients

    Directory of Open Access Journals (Sweden)

    Ferda Özdemir

    2011-09-01

    Full Text Available Objective: Pressure sores are an important source of complications in patients who are immobilized and bedridden. We aimed to investigate the efficiency of magnetic field treatment in pressure sores. Material and Methods: This was a randomized, double blind controlled design study. 20 patients in the study group received magneto-therapy, once a day for 30 minutes and with 150G, keeping to the BTL09 magnetotherapy device’s program. In the control group, 20 patients received the dressing only once a day. The surface areas of the pressure sores were evaluated at the onset of the treatment (1st day, and on the 7th and 15th days.Results: When within group comparisons were conducted, a significant difference was observed between the 1st and 7th day, 7th and 15th day, and 1st and 15th day measures in both the groups in terms of the scar area. The average healing time for the treatment group was 10.80±4.06 (6-20 days, and the average healing time for the control group was 18.85±9.75 (5-32 days. There was a statistically significant difference between the two groups (z=-2.114, p=0.034. Also, there was a significant difference in the scar area between the two groups in the 15th day measure (z=-3.818, p=0.000.Conclusion: The healing process of the tissue can be accelerated.with the use of magnetotherapy in the treatment of pressure sores of stage II and III,

  15. Effect of hydrostatic pressure and magnetic field on electromagnetically induced transparency based nonlinear frequency conversion in quantum ring

    Science.gov (United States)

    Gumber, Sukirti; Gambhir, Monica; Jha, Pradip Kumar; Mohan, Man

    2016-10-01

    We study the combined effect of hydrostatic pressure and magnetic field on electromagnetically induced transparency in quantum ring. The high flexibility in size and shape of ring makes it possible to fabricate a nearly perfect two-dimensional quantum structure. We also explore the dependence of frequency conversion, measured in terms of third order nonlinear susceptibility χ(3) , on coupling field, hydrostatic pressure and magnetic field. Although, a dip in χ(3) is observed with the introduction of strong coupling field, it renders the ring structure transparent to generated wave thus effectively enhancing the output of nonlinear frequency conversion process. At a fixed coupling strength, the output can be further enhanced by increasing the magnetic field while it shows an inverse relationship with pressure. These parameters, being externally controlled, provide an easy handle to control the output of quantum ring which can be used as frequency converter in communication networks.

  16. Design, Fabrication, and Implementation of a Wireless, Passive Implantable Pressure Sensor Based on Magnetic Higher-Order Harmonic Fields

    Directory of Open Access Journals (Sweden)

    Keat Ghee Ong

    2011-10-01

    Full Text Available A passive and wireless sensor was developed for monitoring pressure in vivo. Structurally, the pressure sensor, referred to as the magneto-harmonic pressure sensor, is an airtight chamber sealed with an elastic pressure membrane. A strip of magnetically-soft material is attached to the bottom of the chamber and a permanent magnet strip is embedded inside the membrane. Under the excitation of an externally applied AC magnetic field, the magnetically-soft strip produces a higher-order magnetic signature that can be remotely detected with an external receiving coil. As ambient pressure varies, the pressure membrane deflects, altering the separation distance between the magnetically-soft strip and the permanent magnet. This shifts the higher-order harmonic signal, allowing for detection of pressure change as a function of harmonic shifting. The wireless, passive nature of this sensor technology allows for continuous long-term pressure monitoring, particularly useful for biomedical applications such as monitoring pressure in aneurysm sac and sphincter of Oddi. In addition to demonstrating its pressure sensing capability, an animal model was used to investigate the efficacy and feasibility of the pressure sensor in a biological environment.

  17. Studies on deposition, adhesion and resuspension of radioactive substances on the ground surface and ground cover

    Energy Technology Data Exchange (ETDEWEB)

    Kurita, Susumu; Kurihara, Kazuo [Meteorological Research Inst., Tsukuba, Ibaraki (Japan)

    1999-03-01

    After the Chernobyl` nuclear power plant accident, resuspension of radioactive nuclei into the atmosphere is recognized as the one of the important processes that must be considered in the estimation of inhalation doses to humans. In this study, resuspensions of particles from soil and grass have been studied. The resuspension of particles from bare soil was modelized by using Shao`s method. The resuspension of particles from grass was studied by a wind tunnel and a field experiment. Dependencies of the resuspension rate on time and on friction velocity were obtained clearly. And it was also found that the other meteorological parameters, such as temperature, relative humidity, solar radiation and condensation, affected the resuspension rate in the field. (author)

  18. Simulation of changes in temperature and pressure fields during high speed projectiles forming by explosion

    Directory of Open Access Journals (Sweden)

    Marković Miloš D.

    2016-01-01

    Full Text Available The Research in this paper considered the temperatures fields as the consequently influenced effects appeared by plastic deformation, in the explosively forming process aimed to design Explosively Formed Projectiles (henceforth EFP. As the special payloads of the missiles, used projectiles are packaged as the metal liners, joined with explosive charges, to design explosive propulsion effect. Their final form and velocity during shaping depend on distributed temperatures in explosively driven plastic deformation process. Developed simulation model consider forming process without metal cover of explosive charge, in aim to discover liner’s dynamical correlations of effective plastic strains and temperatures in the unconstrained detonation environment made by payload construction. The temperature fields of the liner’s copper material are considered in time, as the consequence of strain/stress displacements driven by explosion environmental thermodynamically fields of pressures and temperatures. Achieved final velocities and mass loses as the expected EFP performances are estimated regarding their dynamical shaping and thermal gradients behavior vs. effective plastic strains. Performances and parameters are presented vs. process time, numerically simulated by the Autodyne software package. [Projekat Ministarstva nauke Republike Srbije, br. III-47029

  19. History development of the Tijerina-Canales-Blucher (zone 21-b) field high pressure extension area

    Energy Technology Data Exchange (ETDEWEB)

    Harris, G.A.

    1975-01-01

    This study presents (1) the results of a combined engineering/geological study that led to the discovery of several million barrels of additional oil in the nearly 30-yr old Tijerina-Canales-Blucher (21-B) field oil column; (2) the results of a 2-dimensional, 3-phase computer simulation study of the reservoir; and (3) a comparison of actual vs. predicted performance. The new oil area was discovered in late 1972 by drilling Exxon's King Ranch-Tijerina Well A-29 to investigate a possible stratigraphic trap suggested by an observed anomalous high pressure area. Twenty additional wells were drilled before extent of the new oil area was known. A computer model simulator study was made to predict future performance, to determine an optimum water injection program, and to determine if producing rates were compatible with maximum oil recovery.

  20. A COMPARATIVE STUDY ON THE EFFECTS OF THE POLYMER PROSTHETIC BASE PRESSURE OVER THE PROSTHETIC FIELD

    Directory of Open Access Journals (Sweden)

    A.T. Cigu

    2016-04-01

    Full Text Available Partially mobile polymeric prostheses constitute absolutely necessary therapeutical means in all forms of partial edentations. As known, polymeric partial prostheses constitute temporary solutions for the treatment of edentaton states. Nowadays, this treatment includes traditional acrylic prostheses, as well as elastic prostheses made of different material systems. Such a system is Valplast, which uses a polyamide for the realization of the prosthetic base. Both the rigid and the elastic materials are nowadays under debate, different – positive or negative – opinions being uttered in relation with their utilization. The scope of the present study is to support the intensive application of the elastic materials. Extremely important is the identification of the intrinsic qualities of the materials influencing the behaviour in the oral cavity, especially the effects of pressure upon the biological structures of the prosthetic field.

  1. Analysis of the susceptibility of condensed oxygen under high pressures and in strong magnetic fields

    Science.gov (United States)

    Kilit Doğan, E.; Yurtseven, H.

    2017-03-01

    The temperature dependence of the magnetic susceptibility is analyzed at some constant pressures by a power-law formula using the experimental data from the literature for the α - β and β - γ transitions in oxygen. A weak discontinuous (nearly continuous) transition occurring from the α to the β phase, becomes more discontinuous (weakly first order) for the β - γ transition as observed experimentally, which can be explained in terms of the critical exponents deduced from our analysis. The magnetic field dependence of the differential susceptibility is also analyzed in this study for the α -O2 at 4.2 K by a power-law formula using the experimental data. λ-type of observed behaviour of the differential susceptibility is discussed in terms of our analysis for the α -O2 .

  2. Experimental determination of radiated internal wave power without pressure field data

    CERN Document Server

    Lee, Frank M; Swinney, Harry L; Morrison, P J

    2014-01-01

    We present a method to determine, using only velocity field data, the time-averaged energy flux $\\left$ and total radiated power $P$ for two-dimensional internal gravity waves. Both $\\left$ and $P$ are determined from expressions involving only a scalar function, the stream function $\\psi$. We test the method using data from a direct numerical simulation for tidal flow of a stratified fluid past a knife edge. The results for the radiated internal wave power given by the stream function method agree to within 0.5% with results obtained using pressure and velocity data from the numerical simulation. The results for the radiated power computed from the stream function agree well with power computed from the velocity and pressure if the starting point for the stream function computation is on a solid boundary, but if a boundary point is not available, care must be taken to choose an appropriate starting point. We also test the stream function method by applying it to laboratory data for tidal flow past a knife ed...

  3. STRONG SOLAR WIND DYNAMIC PRESSURE PULSES: INTERPLANETARY SOURCES AND THEIR IMPACTS ON GEOSYNCHRONOUS MAGNETIC FIELDS

    Energy Technology Data Exchange (ETDEWEB)

    Zuo, Pingbing; Feng, Xueshang; Wang, Yi [SIGMA Weather Group, State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing (China); Xie, Yanqiong [College of Meteorology and Oceanography, PLA University of Science and Technology, Nanjing (China); Xu, Xiaojun, E-mail: pbzuo@spaceweather.ac.cn, E-mail: fengx@spaceweather.ac.cn [Space Science Institute, Macau University of Science and Technology, Macao (China)

    2015-10-20

    In this investigation, we first present a statistical result of the interplanetary sources of very strong solar wind dynamic pressure pulses (DPPs) detected by WIND during solar cycle 23. It is found that the vast majority of strong DPPs reside within solar wind disturbances. Although the variabilities of geosynchronous magnetic fields (GMFs) due to the impact of positive DPPs have been well established, there appears to be no systematic investigations on the response of GMFs to negative DPPs. Here, we study both the decompression effects of very strong negative DPPs and the compression from strong positive DPPs on GMFs at different magnetic local time sectors. In response to the decompression of strong negative DPPs, GMFs on the dayside near dawn and near dusk on the nightside, are generally depressed. But near the midnight region, the responses of GMF are very diverse, being either positive or negative. For part of the events when GOES is located at the midnight sector, the GMF is found to abnormally increase as the result of magnetospheric decompression caused by negative DPPs. It is known that under certain conditions magnetic depression of nightside GMFs can be caused by the impact of positive DPPs. Here, we find that a stronger pressure enhancement may have a higher probability of producing the exceptional depression of GMF at the midnight region. Statistically, both the decompression effect of strong negative DPPs and the compression effect of strong positive DPPs depend on the magnetic local time, which are stronger at the noon sector.

  4. Electric field determination in streamer discharges in air at atmospheric pressure

    Energy Technology Data Exchange (ETDEWEB)

    Bonaventura, Z; Bourdon, A [EM2C Laboratory, Ecole Centrale Paris, UPR 288 CNRS, Grande voie des vignes, 92295 Chatenay-Malabry Cedex (France); Celestin, S; Pasko, V P, E-mail: zbona@physics.muni.cz [Communications and Space Sciences Laboratory, Department of Electrical Engineering, Pennsylvania State University, University Park, PA 16802 (United States)

    2011-06-15

    The electric field in streamer discharges in air can be easily determined by the ratio of luminous intensities emitted by N{sub 2}(C {sup 3{Pi}}{sub u}) and N{sub 2}{sup +}(B {sup 2{Sigma}}{sub u}{sup +}) if the steady-state assumption of the emitting states is fully justified. At ground pressure, the steady-state condition is not fulfilled and it is demonstrated that its direct use to determine the local and instantaneous peak electric field in the streamer head may overestimate this field by a factor of 2. However, when spatial and time-integrated optical emissions (OEs) are considered, the reported results show that it is possible to formulate a correction factor in the framework of the steady-state approximation and to accurately determine the peak electric field in an air discharge at atmospheric pressure. A correction factor is defined as {Gamma} = E{sub s}/E{sub e}, where E{sub e} is the estimated electric field and E{sub s} is the true peak electric field in the streamer head. It is shown that this correction stems from (i) the shift between the location of the peak electric field and the maximum excitation rate for N{sub 2}(C {sup 3{Pi}}{sub u}) and N{sub 2}{sup +}(B {sup 2{Sigma}}{sub u}{sup +}) as proposed by Naidis (2009 Phys. Rev. E 79 057401) and (ii) from the cylindrical geometry of the streamers as stated by Celestin and Pasko (2010 Geophys. Res. Lett. 37 L07804). For instantaneous OEs integrated over the whole radiating plasma volume, a correction factor of {Gamma} {approx} 1.4 has to be used. For time-integrated OEs, the reported results show that the ratio of intensities can be used to derive the electric field in discharges if the time of integration is sufficiently long (i.e. at least longer than the longest characteristic lifetime of excited species) to have the time to collect all the light from the emitting zones of the streamer. For OEs recorded using slits (i.e. a window with a small width but a sufficiently large radial extension to

  5. Pressure fields by flow-sensitive, 4D, velocity-encoded CMR in patients with aortic coarctation.

    Science.gov (United States)

    Riesenkampff, Eugénie; Fernandes, Joao Filipe; Meier, Sebastian; Goubergrits, Leonid; Kropf, Siegfried; Schubert, Stephan; Berger, Felix; Hennemuth, Anja; Henneumuth, Anja; Kuehne, Titus

    2014-09-01

    This study compared pressure fields by 4-dimensional (4D), velocity-encoded cine (VEC) cardiac magnetic resonance imaging (CMR) with pressures measured by the clinical gold standard catheterization. Thirteen patients (n = 7 male, n = 6 female) with coarctation were studied. The 4D-VEC-CMR pressure fields were computed by solving the Pressure-Poisson equation. The agreement between catheterization and CMR-based methods was determined at 5 different measurement sites along the aorta. For all sites, the correlation coefficients between measures varied between 0.86 and 0.97 (p coarctation. The nonsignificant (p > 0.2) bias was +2.3 mm Hg (± 6.4 mm Hg, 2 SDs) for calibration with dynamic pressures and +1.5 mm Hg (± 4.6 mm Hg, 2 SDs) for calibration with static pressure. In a clinical setting of coarctation, pressure fields can be accurately computed from 4D-VEC-CMR-derived flows. In patients with coarctation, this noninvasive technique might evolve to an alternative to invasive catheterization.

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

    Science.gov (United States)

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

    2016-07-01

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

  7. A system for vertical profile measurements of sensible heat and chemical concentrations near the ground surface

    Energy Technology Data Exchange (ETDEWEB)

    Hyppoenen, M.; Walden, J.A.

    1996-12-31

    The design, construction and measurements of a computer controlled system applicable to flux measurements of a scalar quantity by the gradient technique are described. Accuracy requirements for the measured variables which are used for flux calculations are considered, together with some practical aspects concerning data storage and control. The construction includes the hardware and the data acquisition, sample intake, and temperature measurement systems. The measurements comprise laboratory tests of the temperature probes and the hardware as well as field tests over wheat and grass land for temperature and wind speed and ozone (O{sub 3}), carbon dioxide (CO{sub 2}) and nitrous oxide (N{sub 2}O) concentration profiles. The hardware takes care of most of the operation and only the necessary part is done by the software. The data acquisition system is flexible, accepting the input of either digital and/or analog signals. It also controls the whole system, storing all the data in a single data file. The sample intake unit is designed to take continuous samples in to the monitors as well as grab samples into the canisters. Samples can be selected from one to four levels with no dead volumes in the sampling tubes. The temperature measurement system is constructed using a pair of temperature probes, Pt-100, which are connected to the same signal processing card, in order to remove the offset of the electronic components as well as the bias associated with single probes. This ensures the accuracy of the probes down to 0.005 deg C. According to the field measurements, the relative error limits for the sensible heat fluxes varied from 7 to 20 % in an unstable atmospheric situation. For the ozone flux, the error limits varied from 20 to 100 %, indicating a much poorer accuracy of the monitor compared to the temperature probes. (orig.) 16 refs.

  8. Field test to study the pressure equilization on air permeable facade elements

    NARCIS (Netherlands)

    Bentum, C.A. van; Kalkman, I.M.; Geurts, C.P.W.

    2014-01-01

    The net wind load on the outer layer of a façade consisting of multiple layers is determined by the external pressure and the cavity pressure. For an air-permeable outer layer, the cavity pressure is dependent on the extent to which the external pressure equalizes over the openings. Minimizing the p

  9. A Study of the Fluid-Dynamic Pressure Fields on Compressor Reed Valves.

    Science.gov (United States)

    1985-12-01

    nigher *A pressures. The total pressure ol the reservoir wnicn suppiieo the air was measured on either a lovi-incn mercury manometer or a3 -v)-incn... mercury manometer . This was the same manometer which was used to measure the total pressure of the reservoir. A pressure tap ran from this total

  10. Solar wind dynamic pressure and electric field as the main factors controlling Saturn's aurorae.

    Science.gov (United States)

    Crary, F J; Clarke, J T; Dougherty, M K; Hanlon, P G; Hansen, K C; Steinberg, J T; Barraclough, B L; Coates, A J; Gérard, J-C; Grodent, D; Kurth, W S; Mitchell, D G; Rymer, A M; Young, D T

    2005-02-17

    The interaction of the solar wind with Earth's magnetosphere gives rise to the bright polar aurorae and to geomagnetic storms, but the relation between the solar wind and the dynamics of the outer planets' magnetospheres is poorly understood. Jupiter's magnetospheric dynamics and aurorae are dominated by processes internal to the jovian system, whereas Saturn's magnetosphere has generally been considered to have both internal and solar-wind-driven processes. This hypothesis, however, is tentative because of limited simultaneous solar wind and magnetospheric measurements. Here we report solar wind measurements, immediately upstream of Saturn, over a one-month period. When combined with simultaneous ultraviolet imaging we find that, unlike Jupiter, Saturn's aurorae respond strongly to solar wind conditions. But in contrast to Earth, the main controlling factor appears to be solar wind dynamic pressure and electric field, with the orientation of the interplanetary magnetic field playing a much more limited role. Saturn's magnetosphere is, therefore, strongly driven by the solar wind, but the solar wind conditions that drive it differ from those that drive the Earth's magnetosphere.

  11. Artificially decreased vapour pressure deficit in field conditions modifies foliar metabolite profiles in birch and aspen.

    Science.gov (United States)

    Lihavainen, Jenna; Keinänen, Markku; Keski-Saari, Sarita; Kontunen-Soppela, Sari; Sõber, Anu; Oksanen, Elina

    2016-07-01

    Relative air humidity (RH) is expected to increase in northern Europe due to climate change. Increasing RH reduces the difference of water vapour pressure deficit (VPD) between the leaf and the atmosphere, and affects the gas exchange of plants. Little is known about the effects of decreased VPD on plant metabolism, especially under field conditions. This study was conducted to determine the effects of artificially decreased VPD on silver birch (Betula pendula Roth.) and hybrid aspen (Populus tremula L.×P. tremuloides Michx.) foliar metabolite and nutrient profiles in a unique free air humidity manipulation (FAHM) field experiment during the fourth season of humidity manipulation, in 2011. Long-term exposure to decreased VPD modified nutrient homeostasis in tree leaves, as demonstrated by a lower N concentration and N:P ratio in aspen leaves, and higher Na concentration and lower K:Na ratio in the leaves of both species in decreased VPD than in ambient VPD. Decreased VPD caused a shift in foliar metabolite profiles of both species, affecting primary and secondary metabolites. Metabolic adjustment to decreased VPD included elevated levels of starch and heptulose sugars, sorbitol, hemiterpenoid and phenolic glycosides, and α-tocopherol. High levels of carbon reserves, phenolic compounds, and antioxidants under decreased VPD may modify plant resistance to environmental stresses emerging under changing climate.

  12. The Specific Heat of UGe_2: Effects of Pressure and Magnetic Field

    Science.gov (United States)

    Fisher, R. A.; Bouquet, F.; Lashley, J. C.; Phillips, N. E.; Huxley, A.; Flouquet, J.

    2003-03-01

    At ambient pressure (P) UGe2 undergoes transitions from paramagnetic, to ferromagnetic (FM), to coupled charge-density wave (CDW) spin-density wave (SDW) phases on cooling. Within a narrow range of P, and at temperatures (T) below ˜0.7 K (but depending on sample quality), superconductivity (SC) coexists with both the CDW-SDW and FM phases. The γT term for the specific heat (C) increases with increasing P, most rapidly between ˜1 and ˜1.4 GPa, the region in which SC develops, then approaches a constant value at 1.8 GPa. The γT term decreases in a magnetic field. In the CDW-SDW region of the phase diagram C includes an exponential term that represents the CDW-SDW and decreases in a magnetic field. The electronic entropy increases rapidly in a narrow interval of P in the vicinity of the CDW-SDW transition, which suggests that it might be broadened first order. A transition to SC is not observed to 0.35 K in the range of P where it is expected to occur, but there are upturns in C/T, absent at other P's, that suggest the onset of SC.

  13. The research about the multi-freedom degree reciprocity principle for diffuse sound field based on the sound pressure field description

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The multi-DOF(degree-of-freedom) reciprocity principle for diffuse field was proposed and applied in the mid-frequency analysis of a complex vibro-acoustic system.As the application of this diffuse reciprocity principle in a sound field leads the model to be unnecessarily enormous,one multi-DOF acoustic reciprocity principle more applicable for diffuse sound field is proposed here.First,the"blocked"model of diffuse sound field is proposed to describe the blocked sound pressure on the surface of a structu...

  14. Comparison of Mid-latitude Cyclones in Sea Level Pressure, Gepotential Height and Vorticity Fields

    Science.gov (United States)

    Raible, Christoph C.; Blender, Richard; Fraedrich, Klaus

    2013-04-01

    The mid-latitudes are dominated by diurnal variability, which is related to traveling high- and low-pressure systems. The lows or cyclones are a major source of natural hazards. This has led to growing interest in the scientific community to develop Eulerian and Lagrangian measures and to analyze the atmospheric high-frequency variability. One important issue is that there is no straight forward definition of cyclones resulting in a large variety of so-called cyclone detection and tracking methods. Each of these methods relies on different input fields which are related to specific features of a cyclone, e.g., sea level pressure (SLP), which specifically focuses on the mass aspect of the velocity field. Recently, the available methods have been compared with respect to climatology and life cycles using the ERA interim data set (Neu et al. 2013). Based on this study we investigate different fields as input for one specific method. We focus on the three mostly used input data, sea level pressure (SLP), 1000-hPa gepotential height (Z1000) and 850-hPa vorticity (850VOR). The cyclone detection and tracking method developed by Blender et al. (1997) is used and we apply it to ERA interim data in the 1.5 x 1.5 resolution. The method was mainly applied for Z1000 and the Northern Hemisphere (e.g., Blender et al. 1997; Raible et al. 2008). To compare the tracks and cyclone characteristics obtained from the different input data we need to adapt critical parameters of the method in such a way that comparable numbers of cyclone centers are identified in either field. The target is set to the number of cyclone centers in northern hemispheric winter. This enables us to assess the seasonal and hemispheric dependence. Preliminary results show that the agreement between cyclones based on SLP and Z1000 varies between roughly 70 to 80% depending on the season and the hemisphere. Spatially, most of the differences are found around orographic features like Greenland. An interesting

  15. Investigation on the Determination of Initial Shock Pressure at Near Interface Field of TNT Charge and Water for Underwater Explosion

    Institute of Scientific and Technical Information of China (English)

    WU Cheng; ZHANG Xiang-rong; HUANG Feng-lei; SHI Jing-zhu; ZHANG Yu-xia

    2007-01-01

    There are few report on the directly measurement of the initial shock pressure of explosive charge at its interface of water for underwater explosion.The special technologies have been taken to the measurement system with manganin piezoresistive gauge (PRG) in order to measure the initial shock pressure at the interface and its near field of TNT chare and water.The free-holding PRG film gauge can directly determine the shock peak pressure at the interface and near field of TNT charge up to 12.85GPa, which is satisfying for the good agreement to the 12.97GPa with one dimensional theoretical analysis and 12.86GPa with numerical simulation.The maximum discrepancy is 0.93%.The results show that it is precise and reliable to determine the initial shock pressure of underwater explosion charge with the PRG technology.

  16. Practical application of pressure regulating technology for fire district in Meiyukou Coal Mine

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qing-feng; JIA Bao-shan

    2008-01-01

    Based on the simulated laboratory experiment of pressure balance for fire ex-tinguishing, the pressure regulating technology was summarized for the fire district in Meiyukou Coal Mine. The technology includes three measures for air pressure regulation, namely applying the pressure regulating chamber to balance the air pressure of fire district, increasing the air pressure of the working face, and filling the ground surface fractures. A good effect was obtained to prevent and extinguish the fire. When the measures fail to in-crease the pressure of working face or to regulate that of air chamber, the measure to fill the ground surface fractures will play an important role.

  17. Practical application of pressure regulating technology for fire district in Meiyukou Coal Mine

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qing-feng; JIA Bao-shan

    2008-01-01

    Based on the simulated laboratory experiment of pressure balance for fire extinguishing,the pressure regulating technology was summarized for the fire district in Meiyukou Coal Mine.The technology includes three measures for air pressure regulation,namely applying the pressure regulating chamber to balance the air pressure of fire district,increasing the air pressure of the working face,and filling the ground surface fractures.A good effect was obtained to prevent and extinguish the fire.When the measures fail to increase the pressure of working face or to regulate that of air chamber,the measure to fill the ground surface fractures will play an important role.

  18. Workplace field testing of the pressure drop of particulate respirators using welding fumes.

    Science.gov (United States)

    Cho, Hyun-Woo; Yoon, Chung-Sik

    2012-10-01

    In a previous study, we concluded that respirator testing with a sodium chloride aerosol gave a conservative estimate of filter penetration for welding fume aerosols. A rapid increase in the pressure drop (PD) of some respirators was observed as fumes accumulated on the filters. The present study evaluated particulate respirator PD based on workplace field tests. A field PD tester was designed and validated using the TSI 8130 Automatic Filter Tester, designed in compliance with National Institute for Occupational and Safety and Health regulation 42 CFR part 84. Three models (two replaceable dual-type filters and one replaceable single-type filter) were evaluated against CO(2) gas arc welding on mild steel in confined booths in the workplace. Field tests were performed under four airborne concentrations (27.5, 15.4, 7.9, and 2.1 mg m(-3)). The mass concentration was measured by the gravimetric method, and number concentration was monitored using P-Trak (Model 8525, TSI, USA). Additionally, photos and scanning electron microscopy-energy dispersive X-ray spectroscopy were used to visualize and analyze the composition of welding fumes trapped in the filters. The field PD tester showed no significant difference compared with the TSI tester. There was no significant difference in the initial PD between laboratory and field results. The PD increased as a function of fume load on the respirator filters for all tested models. The increasing PD trend differed by models, and PD increased rapidly at high concentrations because greater amount of fumes accumulated on the filters in a given time. The increase in PD as a function of fume load on the filters showed a similar pattern as fume load varied for a particular model, but different patterns were observed for different models. Images and elemental analyses of fumes trapped on the respirator filters showed that most welding fumes were trapped within the first layer, outer web cover, and second layer, in order, while no fumes

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

    Science.gov (United States)

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

    2003-04-01

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

  20. Donor impurity-related intraband optical absorption in a single quantum ring: Hydrostatic pressure and intense laser field effects

    Science.gov (United States)

    Barseghyan, M. G.

    2016-10-01

    The simultaneous influence of hydrostatic pressure and intense laser field on hydrogenic donor impurity states and intraband optical absorption has been investigated in GaAs/Ga_{1-tilde{x}}Al_{tilde{x}}As quantum ring. The one-electron energy spectrum and wave functions have been found using the effective mass approximation and exact diagonalization technique. The intraband absorption coefficient is calculated for different values of the hydrostatic pressure, intense laser field parameter and different locations of hydrogenic donor impurity. The simultaneous influence of hydrostatic pressure and intense laser field shows that while the increment of the first one leads only to the blueshift of the absorption spectrum, the augmentation of the second one makes the redshift. In addition, both blueshift and redshift of the spectrum have been obtained with the changes of impurity location. The obtained theoretical results indicate good controlling means of the optical spectrum of ring-like structures by the combined influence of the considered factors.

  1. Effect of Gradual Onset +G(sub z) Acceleration on Rate of Visual Field Collapse and Intraocular Pressure

    Science.gov (United States)

    Haines, Richard F.; Rositano, Salvador A.; Greenleaf, John E.

    1976-01-01

    The mechanisms that control the size of the visual field during positive acceleration are poorly understood, but involve mainly the arterial blood pressure at the eye level and intraocular pressure (IOP) (3). Fluid and electrolyte shifts that occur in the general circulation during acceleration may well influence the rate at which the visual field collapses. This could, in turn, suggest the relative influences that arterial blood pressure, IOP, and various compensatory mechanisms have upon acceleration tolerance. Such knowledge could also be of use in the design and development of protective techniques for use in the acceleration environment. The present investigation was performed to study blood withdrawal (hypovolemia) and subsequent reinfusion, oral fluid replacement upon IOP, and the rate at which the visual field collapses during gradual onset +G(sub z) acceleration (0.5 G/min).

  2. Elastic anomalies of SmRu{sub 4}P{sub 12} under high pressure and magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Sun, P.; Nakanishi, Y.; Fujino, T.; Nakamura, M. [Graduate School of Engineering, Iwate University, Morioka 020-8551 (Japan); Ohashi, M.; Oomi, G. [Faculty of Science, Kyushu University, Fukuoka 810-8560 (Japan); Sekine, C.; Shirotani, I. [Faculty of Engineering, Muroran Institute of Technology, Muroran 050-8585 (Japan); Yoshizawa, M. [Graduate School of Engineering, Iwate University, Morioka 020-8551 (Japan)], E-mail: yoshizawa@iwate-u.ac.jp

    2008-04-01

    We have measured the transverse elastic constant of SmRu{sub 4}P{sub 12} under hydrostatic pressure of 0.35 GPa in the magnetic field up to 12 T. The magnetic transition temperature is enhanced by applying pressure in large, while the metal-insulator (M-I) transition temperature increases slightly. These behaviors are very consistent with the evaluation of Grueneisen parameters by using the thermodynamic relation. The order parameter for the M-I transition was discussed on the basis of this pressure experiment.

  3. Neural Network Prediction of Failure of Damaged Composite Pressure Vessels from Strain Field Data Acquired by a Computer Vision Method

    Science.gov (United States)

    Russell, Samuel S.; Lansing, Matthew D.

    1997-01-01

    This effort used a new and novel method of acquiring strains called Sub-pixel Digital Video Image Correlation (SDVIC) on impact damaged Kevlar/epoxy filament wound pressure vessels during a proof test. To predict the burst pressure, the hoop strain field distribution around the impact location from three vessels was used to train a neural network. The network was then tested on additional pressure vessels. Several variations on the network were tried. The best results were obtained using a single hidden layer. SDVIC is a fill-field non-contact computer vision technique which provides in-plane deformation and strain data over a load differential. This method was used to determine hoop and axial displacements, hoop and axial linear strains, the in-plane shear strains and rotations in the regions surrounding impact sites in filament wound pressure vessels (FWPV) during proof loading by internal pressurization. The relationship between these deformation measurement values and the remaining life of the pressure vessels, however, requires a complex theoretical model or numerical simulation. Both of these techniques are time consuming and complicated. Previous results using neural network methods had been successful in predicting the burst pressure for graphite/epoxy pressure vessels based upon acoustic emission (AE) measurements in similar tests. The neural network associates the character of the AE amplitude distribution, which depends upon the extent of impact damage, with the burst pressure. Similarly, higher amounts of impact damage are theorized to cause a higher amount of strain concentration in the damage effected zone at a given pressure and result in lower burst pressures. This relationship suggests that a neural network might be able to find an empirical relationship between the SDVIC strain field data and the burst pressure, analogous to the AE method, with greater speed and simplicity than theoretical or finite element modeling. The process of testing SDVIC

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

    Science.gov (United States)

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

    2009-12-01

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

  5. Increasing gas output by an active water-pressure regime interaction in a massive deposit at the Korobsk field

    Energy Technology Data Exchange (ETDEWEB)

    Trubaev, V.L.; Shandrygin, A.N.

    1983-02-01

    Controlled water flooding and pressurization were used to increase the gas output at the Korobsk field (USSR). The mechanics of gas accumulation under flooding conditions depend on the macroheterogeneity of the collector; optimizing the gas output involves selective flooding and pressurizing the water to prevent gas pocket formation in the zones bypassed by the flooded front. Strata mapping of the Korobsk field, combined with theoretical and laboratory studies of the geological characteristics of the deposit, has made it possible to estimate the location and distribution of the various types of residual gas pockets.

  6. GeoLab in NASA's Pressurized Excursion Module: First Results from the 2010 Field Trials

    Science.gov (United States)

    Evans, Cynthia A.; Calaway, Michael; Bell, Mary Sue; Graff, Trevor

    2010-01-01

    Before humans explore other planets, NASA must develop advanced techniques for collection, preservation and return of unique extraterrestrial samples. To help evaluate hardware requirements and operational concepts for future sample-return missions, we designed and built GeoLab our first generation lab for geological samples into NASA s Habitat Demonstration Unit in the Pressurized Excursion Module (HDU1-PEM). The center of GeoLab is a glovebox for the examination of samples in a shirt-sleeve environment. As part of a deployable habitat, GeoLab can participate in NASA s analog missions that simulate planetary exploration activities and support the testing of relevant technologies for collecting and handling geological samples. Over time, these tests will evaluate sample handling environments (field and lab), sampling tools and analytical instruments, and different scenarios involving both robotic and human procedures. The GeoLab design supports evolving tests and configurations. The glovebox is mounted on the habitat bulkhead, with three sample pass-though chambers that allow for direct sample transfer into the glovebox from the outside. The glovebox design and construction (low-particle shedding, minimally off-gassing materials) provides a clean environment to reduce sample contamination; in the future, we will integrate a positive pressure, enriched nitrogen atmosphere. The glovebox is equipped with configurable instrument ports. The 2010 test included a mass balance, a stereomicroscope with a HD camera for detailed imaging of samples, and a handheld XRF analyzer for preliminary geochemical characterization of samples. Network cameras provided context imagery and sample handling activities. We present early results from the initial field trial of GeoLab during the 2010 Desert Research and Technology Studies (D-RATS) planetary analog test near Flagstaff AZ. The 2010 D-RATS mission involved two rovers, the habitat with GeoLab, four crew members, and a team of

  7. Assessment of Field Experience Related to Pressurized Water Reactor Primary System Leaks

    Energy Technology Data Exchange (ETDEWEB)

    Shah, Vikram Naginbhai; Ware, Arthur Gates; Atwood, Corwin Lee; Sattison, Martin Blaine; Hartley, Robert Scott; Hsu, C.

    1999-08-01

    This paper presents our assessment of field experience related to pressurized water reactor (PWR) primary system leaks in terms of their number of rates, how aging affects frequency of leak events, the safety significance of such leaks, industry efforts to reduce leaks, and effectiveness of current leak detection systems. We have reviewed the licensee event reports to identify the events that took place during 1985 to the third quarter of 1996, and reviewed related technical literature and visited PWR plants to analyze these events. Our assessment shows that USNRC licensees have taken effective actions to reduce the number of leak events. One main reason for this decreasing trend was the elimination or reportable leakages from valve stem packing after 1991. Our review of leak events related to vibratory fatigue reveals a statistically significant decreasing trend with age (years of operation), but not in calendar time. Our assessment of worldwide data on leakage caused by thermal fatigue cracking is that the fatigue of aging piping is a safety significant issue. Our review of leak events has identified several susceptible sites in piping having high safety significance; but the inspection of some of these sites is not required by the ASME Code. These sites may be included in the risk-informed inspection programs.

  8. Assessment of Field Experience Related to Pressurized Water Reactor Primary System Leaks

    Energy Technology Data Exchange (ETDEWEB)

    A. G. Ware; C. Hsu (USNRC); C. L. Atwood; M. B. Sattison; R. S. Hartley (INEEL); V. N. Shah

    1999-02-01

    This paper presents our assessment of field experience related to pressurized water reactor (PWR) primary system leaks in terms of their number and rates, how aging affects frequency of leak events, the safety significance of such leaks, industry efforts to reduce leaks, and effectiveness of current leak detection systems. We have reviewed the licensee event reports to identify the events that took place during 1985 to the third quarter of 1996, and reviewed related technical literature and visited PWR plants to analyze these events. Our assessment shows that USNRC licensees have taken effective actions to reduce the number of leak events. One main reason for this decreasing trend was the elimination or reportable leakages from valve stem packing after 1991. Our review of leak events related to vibratory fatigue reveals a statistically significant decreasing trend with age (years of operation), but not in calendar time. Our assessment of worldwide data on leakage caused by thermal fatigue cracking is that the fatigue of aging piping is a safety significant issue. Our review of leak events has identified several susceptible sites in piping having high safety significance; but the inspection of some of these sites is not required by the ASME Code. These sites may be included in the risk-informed inspection programs.

  9. Pressure-anisotropy-driven microturbulence and magnetic-field evolution in shearing, collisionless plasma

    CERN Document Server

    Melville, S; Kunz, M W

    2015-01-01

    The nonlinear state of a high-beta collisionless plasma is investigated when an imposed linear shear amplifies or diminishes a uniform magnetic field, driving pressure anisotropies and hence firehose/mirror instabilities. The evolution of the resulting microscale turbulence is considered when the shear is switched off or reversed after one shear time (mimicking local behaviour of a macroscopic flow), so a new macroscale configuration is superimposed on the microscale state left behind by the previous one. There is a threshold value of plasma beta: when $\\beta\\ll\\Omega/S$ (ion cyclotron frequency/shear rate), the emergence of firehose/mirror fluctuations driven unstable by shear and their disappearance when the shear is removed/reversed are quasi-instantaneous compared to the shear time, viz., the decay time of these fluctuations is $\\sim\\beta/\\Omega \\ll 1/S$ (this result follows from the free decay of the fluctuations being constrained by the same marginal-stability thresholds as their growth). In contrast, w...

  10. Dynamic range and sensitivity of field emission pressure sensors with non-silicon membranes

    Energy Technology Data Exchange (ETDEWEB)

    Badi, N., E-mail: nbadi@uh.edu [Center for Advanced Materials (CAM), University of Houston, Houston, TX 77204-5004 (United States); Physics Department, University of Houston, Houston, TX 77204-5005 (United States); Bensaoula, A. [Physics Department, University of Houston, Houston, TX 77204-5005 (United States); Nair, A.M. [Center for Advanced Materials (CAM), University of Houston, Houston, TX 77204-5004 (United States)

    2013-11-15

    We report on the dynamic range and sensitivity simulations of a functional field emission-based pressure sensor. The device comprises a titanium nitride membrane acting as the anode in front of a flat boron nitride cold cathode emitter. We previously reported the problem of non-linearity of these sensors and studied their performance for different membrane geometries and membranes using different materials such as Si, Ti, Ta, and TiN [N. Badi et al., Appl. Surf. Sci. 256 (2010) 4990–4994]. Of the materials investigated, TiN seems to have the most desirable characteristics with respect to linearity. In this paper we report on the effects of membrane dimensions on the sensor operation. Results show how a sensor having a TiN membrane of standard dimension can be tuned during operation to have maximum dynamic range without affecting the sensitivity. The membrane dimensions have a strong effect on the device dynamic range. Small portions of the entire range could however be selected by changing the device operating voltage. We also have shown that smaller area membranes result in devices with better response in terms of constant sensitivity, as compared to those with thicker membranes. The device can be operated over its entire dynamic range by tuning the operating voltage of the device to keep the sensitivity a constant.

  11. Reconstruction of the 500-year ground surface temperature history of northern Awaji Island, southwest Japan, using a layered thermal property model

    Science.gov (United States)

    Goto, Shusaku; Yamano, Makoto

    2010-12-01

    Changes in the ground surface temperature (GST), propagating underground, can be recorded as thermal perturbations to the background thermal field. This paper presents a forward model of conductive propagation of GST in a layered material model with uniform thermal properties in each layer and a series of step functions as GST history. This model, which is expressed using the same mathematical form of that for a uniform thermal property model with a series of step functions as GST history, calculates subsurface temperature perturbations that originate from the GST change by superimposing numerically solved solutions of the model with surface boundary condition of a unit function. Using this model, we reconstruct the recent 500-year GST history from borehole temperature data in northern Awaji Island, southwest Japan, by Bayesian inversion. The reconstructed GST history shows the onset of warming in the mid-18th century to the early 19th century and an increase of 1.1-1.3 K up to the mid-20th century. From the middle to late 20th century, the GST decreased by about 0.2 K. The GST change in the 20th century fits the trend of mean annual surface air temperature records in Kobe, opposite the coast of northern Awaji Island. The GST history in northern Awaji Island differs from that in Ulsan, in the southeastern Republic of Korea, which is located at the same latitude as northern Awaji Island. Differences of the GST histories of these regions most likely reflect differences in sea surface temperatures in these regions.

  12. Structure of the quasi-steady electromagnetic field of a high frequency industrial discharge at atmospheric pressure

    Science.gov (United States)

    Kirpichnikov, A. P.

    1994-02-01

    An approximate analytical solution of the Maxwell equations is obtained; this solution satisfactorily describes the structure of the quasi-steady electromagnetic field of a high-frequency atmospheric-pressure inductional discharge close to the axis of the plasma bunch.

  13. High pressure and high magnetic field behaviour of free and donor-bound-exciton photoluminescence in InSe

    Energy Technology Data Exchange (ETDEWEB)

    Millot, M.; Broto, J.M.; Leotin, J. [Laboratoire National des Champs Magnetiques Pulses, Universite de Toulouse (France); Gilliland, S.; Segura, A. [ICMUV-Malta Consolider Team, Universitat de Valencia, Valencia (Spain); Gonzalez, J. [Centro de Estudio de Semiconductores, Universidad de Los Andes, Merida (Venezuela); DCITIMAC-Malta Consolider Team, Universidad de Cantabria, Santander (Spain); Chevy, A. [Institut de Mineralogie et de Physique des Milieux Condenses, CNRS, Universite Pierre et Marie Curie Paris 6, 75015 Paris (France)

    2009-03-15

    We report here first magneto-photoluminescence investigations under high pressure up to 6 GPa on III-VI layered semiconductor InSe. Both diamagnetism and magnetic field induced gap opening driven by Landau quantization became observable by using a 60 T pulsed magnet. The pressure-induced enhancement of the diamagnetic coefficient is consistent with the increase of the dielectric constant under pressure while the evolution of the linear coefficient is consistent with a slight increase of the electron effective mass up to 4 GPa and a direct-to-indirect conduction-band crossover around that pressure. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  14. [Effects of ground surface mulching in tea garden on soil water and nutrient dynamics and tea plant growth].

    Science.gov (United States)

    Sun, Li-tao; Wang, Yu; Ding, Zhao-tang

    2011-09-01

    Taking a 2-year-old tea garden in Qingdao of Shandong Province as test object, this paper studied the effects of different mulching modes on the soil water and nutrient dynamics and tea plant growth. Four treatments were installed, i.e., no mulching (CK), straw mulching (T1), plastic film mulching (T2), and straw plus plastic film mulching (T3). Comparing with CK, mulching could keep the soil water content at a higher level, and enhance the water use efficiency. In treatments T1 and T3, the tea growth water use efficiency and yield water use efficiency increased by 43%-48% and 7%-13%, respectively, compared with CK. Also in treatments T1 and T3, the contents of soil organic matter, available-N, nitrate-N, and ammonium-N increased significantly, with the soil fertility improved, and the leaf nitrate-N content and nitrate reductase activity increased, which promoted the tea growth and yield (12%-13% higher than CK) and made the peak period of bud growth appeared earlier. Considering the tea growth and yield, water and nutrient use efficiency, environment safety and economic benefit, straw mulching could be an effective ground surface mulching mode for young tea garden.

  15. A study of SO2 emissions and ground surface displacements at Lastarria volcano, Antofagasta Region, Northern Chile

    Science.gov (United States)

    Krewcun, Lucie G.

    Lastarria volcano (Chile) is located at the North-West margin of the 'Lazufre' ground inflation signal (37x45 km2), constantly uplifting at a rate of ˜2.5 cm/year since 1996 (Pritchard and Simons 2002; Froger et al. 2007). The Lastarria volcano has the double interest to be superimposed on a second, smaller-scale inflation signal and to be the only degassing area of the Lazufre signal. In this project, we compared daily SO2 burdens recorded by AURA's OMI mission for 2005-2010 with Ground Surface Displacements (GSD) calculated from the Advanced Synthetic Aperture Radar (ASAR) images for 2003-2010. We found a constant maximum displacement rate of 2.44 cm/year for the period 2003-2007 and 0.80- 0.95 cm/year for the period 2007-2010. Total SO 2 emitted is 67.0 kT for the period 2005-2010, but detection of weak SO2 degassing signals in the Andes remains challenging owing to increased noise in the South Atlantic radiation Anomaly region.

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

    Energy Technology Data Exchange (ETDEWEB)

    Chroszcz, A.

    1985-01-01

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

  17. Validation of the Cooray‐Rubinstein (C‐R) formula for a rough ground surface by using three‐dimensional (3‐D) FDTD

    National Research Council Canada - National Science Library

    Li, Dongshuai; Zhang, Qilin; Liu, Tao; Wang, Zhenhui

    2013-01-01

    In this paper, we have extended the Cooray‐Rubinstein (C‐R) approximate formula into the fractal rough ground surface and then validate its accuracy by using three‐dimensional (3‐D) finite‐difference time‐domain (FDTD...

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

    Science.gov (United States)

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

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

    Science.gov (United States)

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

    2016-11-01

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

  20. Near Field Pressure for an Infinite Phased Array of Circular Pistons,

    Science.gov (United States)

    1966-06-01

    kd1 = kd2 = 3, ka = 1,I ky = kz = 0. For 9~ = 0° the pressure distribution is relatively smooth, while for larger angles it becomes more undulatory ...would have 1PII The single-term approximation P1 does not show any I undulatory behavior ; therefore let us obtain a two-term approxi- mation to explain...the undulatory pressure is shown, because due to symmetry the pressure values are repeated at x, x ± d1, x ± 2d1, etc . The pressure dis- tribution

  1. The smooth transition from field emission to a self-sustained plasma in microscale electrode gaps at atmospheric pressure

    Science.gov (United States)

    Bilici, Mihai A.; Haase, John R.; Boyle, Calvin R.; Go, David B.; Sankaran, R. Mohan

    2016-06-01

    We report on the existence of a smooth transition from field emission to a self-sustained plasma in microscale electrode geometries at atmospheric pressure. This behavior, which is not found at macroscopic scales or low pressures, arises from the unique combination of large electric fields that are created in microscale dimensions to produce field-emitted electrons and the high pressures that lead to collisional ionization of the gas. Using a tip-to-plane electrode geometry, currents less than 10 μA are measured at onset voltages of ˜200 V for gaps less than 5 μm, and analysis of the current-voltage (I-V) relationship is found to follow Fowler-Nordheim behavior, confirming field emission. As the applied voltage is increased, gas breakdown occurs smoothly, initially resulting in the formation of a weak, partial-like glow and then a self-sustained glow discharge. Remarkably, this transition is essentially reversible, as no significant hysteresis is observed during forward and reverse voltage sweeps. In contrast, at larger electrode gaps, no field emission current is measured and gas breakdown occurs abruptly at higher voltages of ˜400 V, absent of any smooth transition from the pre-breakdown condition and is characterized only by glow discharge formation.

  2. The smooth transition from field emission to a self-sustained plasma in microscale electrode gaps at atmospheric pressure

    Energy Technology Data Exchange (ETDEWEB)

    Bilici, Mihai A.; Boyle, Calvin R.; Sankaran, R. Mohan, E-mail: dgo@nd.edu, E-mail: mohan@case.edu [Department of Chemical and Biomolecular Engineering, Case Western Reserve University, Cleveland, Ohio 44106 (United States); Haase, John R. [Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, Indiana 46556 (United States); Go, David B., E-mail: dgo@nd.edu, E-mail: mohan@case.edu [Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, Indiana 46556 (United States); Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556 (United States)

    2016-06-14

    We report on the existence of a smooth transition from field emission to a self-sustained plasma in microscale electrode geometries at atmospheric pressure. This behavior, which is not found at macroscopic scales or low pressures, arises from the unique combination of large electric fields that are created in microscale dimensions to produce field-emitted electrons and the high pressures that lead to collisional ionization of the gas. Using a tip-to-plane electrode geometry, currents less than 10 μA are measured at onset voltages of ∼200 V for gaps less than 5 μm, and analysis of the current–voltage (I-V) relationship is found to follow Fowler–Nordheim behavior, confirming field emission. As the applied voltage is increased, gas breakdown occurs smoothly, initially resulting in the formation of a weak, partial-like glow and then a self-sustained glow discharge. Remarkably, this transition is essentially reversible, as no significant hysteresis is observed during forward and reverse voltage sweeps. In contrast, at larger electrode gaps, no field emission current is measured and gas breakdown occurs abruptly at higher voltages of ∼400 V, absent of any smooth transition from the pre-breakdown condition and is characterized only by glow discharge formation.

  3. Micrometeorological measurements and vapour pressure deficit relations under in-field rainwater harvesting

    Science.gov (United States)

    Tesfuhuney, Weldemichael A.; Walker, Sue; Van Rensburg, Leon D.; Steyn, A. Stephan

    2016-08-01

    In a cropped field, microclimate and thermal stability conditions depend on the canopy structures and the prevailing weather. The main aim of the study therefore was to characterize the vertical profiles of weather variables within and above a maize (Zea mays L.) canopy and to describe the water vapour pressure deficit (VPD) under different atmospheric and soil surface conditions for both wide and narrow runoff strips with the in-field rainwater harvesting (IRWH) system. Micrometeorological measurements of wind, temperature and relative humidity were performed at eight levels, within canopy (1.8 and 2.1 m), and just above the canopy (2.4, 2.7, 3.0, and 3.3 m) up to reference levels (3.9 and 4.5 m) when the maize reached a maximum height of 2.2 m. Under incomplete canopy cover of the IRWH system, two important factors complicated evapotranspiration estimation, namely the local advection and high temperatures of the bare soil between adjacent plant rows. Diurnal variations of water vapour related to turbulence at each locality and its position in the thermal internal boundary layers. Generally, advection was more pronounced in wide runoff strips than narrow strips. On wide runoff strips the wind was more effective in replacing the air between the rows and maintained a higher driving force for evaporation. The maximum VPD over the narrow strips was observed at reference level during a dry day, at about 2.2 kPa in the afternoon, while wet day VPD reached a maximum of 1.8 kPa. The VPD of the wide runoff strips correlated negatively with wind speed, but showed a fairly positive correlation with some scattered values on wet days after rain. Therefore, profile characteristics within and above plant canopies played a key role in determining the VPD and consequently, could help to explain transpiration rates of crops. Hence, VPD relations enhanced the understanding of the heat energy exchange processes under the heterogeneous nature of maize canopy of the IRWH tillage system.

  4. Thermodynamic properties of rhodium at high temperature and pressure by using mean field potential approach

    Science.gov (United States)

    Kumar, Priyank; Bhatt, Nisarg K.; Vyas, Pulastya R.; Gohel, Vinod B.

    2016-10-01

    The thermophysical properties of rhodium are studied up to melting temperature by incorporating anharmonic effects due to lattice ions and thermally excited electrons. In order to account anharmonic effects due to lattice vibrations, we have employed mean field potential (MFP) approach and for thermally excited electrons Mermin functional. The local form of the pseudopotential with only one effective adjustable parameter rc is used to construct MFP and hence vibrational free energy due to ions - Fion. We have studied equation of state at 300 K and further, to access the applicability of present conjunction scheme, we have also estimated shock-Hugoniot and temperature along principle Hugoniot. We have carried out the study of temperature variation of several thermophysical properties like thermal expansion (βP), enthalpy (EH), specific heats at constant pressure and volume (CP and CV), specific heats due to lattice ions and thermally excited electrons ( and , isothermal and adiabatic bulk moduli (BT and Bs) and thermodynamic Gruneisen parameter (γth) in order to examine the inclusion of anharmonic effects in the present study. The computed results are compared with available experimental results measured by using different methods and previously obtained theoretical results using different theoretical philosophy. Our computed results are in good agreement with experimental findings and for some physical quantities better or comparable with other theoretical results. We conclude that local form of the pseudopotential used accounts s-p-d hybridization properly and found to be transferable at extreme environment without changing the values of the parameter. Thus, even the behavior of transition metals having complexity in electronic structure can be well understood with local pseudopotential without any modification in the potential at extreme environment. Looking to the success of present scheme (MFP + pseudopotential) we would like to extend it further for the

  5. Flow and heat transfer in gas turbine disk cavities subject to nonuniform external pressure field

    Energy Technology Data Exchange (ETDEWEB)

    Roy, R.P.; Kim, Y.W.; Tong, T.W. [Arizona State Univ., Tempe, AZ (United States)

    1995-10-01

    Injestion of hot gas from the main-stream gas path into turbine disk cavities, particularly the first-stage disk cavity, has become a serious concern for the next-generation industrial gas turbines featuring high rotor inlet temperature. Fluid temperature in the cavities increases further due to windage generated by fluid drag at the rotating and stationary surfaces. The resulting problem of rotor disk heat-up is exacerbated by the high disk rim temperature due to adverse (relatively flat) temperature profile of the mainstream gas in the annular flow passage of the turbine. A designer is concerned about the level of stresses in the turbine rotor disk and its durability, both of which are affected significantly by the disk temperature distribution. This distribution also plays a major role in the radial position of the blade tip and thus, in establishing the clearance between the tip and the shroud. To counteract mainstream gas ingestion as well as to cool the rotor and the stator disks, it is necessary to inject cooling air (bled from the compressor discharge) into the wheel space. Since this bleeding of compressor air imposes a penalty on the engine cycle performance, the designers of disk cavity cooling and sealing systems need to accomplish these tasks with the minimum possible amount of bleed air without risking disk failure. This requires detailed knowledge of the flow characteristics and convective heat transfer in the cavity. The flow in the wheel space between the rotor and stator disks is quite complex. It is usually turbulent and contains recirculation regions. Instabilities such as vortices oscillating in space have been observed in the flow. It becomes necessary to obtain both a qualitative understanding of the general pattern of the fluid motion as well as a quantitative map of the velocity and pressure fields.

  6. On the Frontier of the Hunt for Jellyfish Galaxies: Ram-Pressure Stripping in the Hubble Frontier Fields

    Science.gov (United States)

    McPartland, Conor; Ebeling, Harald

    2015-08-01

    Using quantitative morphological selection criteria, we search for evidence of galaxies experiencing ram-pressure stripping (RPS) in the Hubble Frontier Fields. The broader areal coverage of these clusters, provided by the complementary parallel fields, allow us to sample regions near to the expected stripping radius of the cluster (˜1 Mpc), where we expect to find the highest density of events. Expanding the number of known events (especially at large cluster-centric radii) will allow us to disentangle the relative contributions of "normal" galaxy infall and cluster mergers in producing the events we observe. We present observational characteristics of the best RPS candidates from the Frontier Fields. Finally, we use these objects, along with RPS events previously identified in the literature, to make quantitative comparisons with predictions of theoretical and numerical models of ram-pressure stripping.

  7. Experimental investigation of the surface pressure field for prediction of trailing edge noise of wind turbine aerofoils

    DEFF Research Database (Denmark)

    Fischer, Andreas; Aagaard Madsen, Helge; Bertagnolio, Franck

    2015-01-01

    This paper concerns the characterisation of turbulent boundary layer trailing edge noise by measuring the surface pressure field. Two aerofoils typically used at the outer blade section of modern MW wind turbines were tested in an anechoic wind tunnel for Reynolds numbers ranging from 1 million...... used as input to the model. There was a factor of 2 as difference between the two models. The prediction of the far field trailing edge noise with one model was in excellent agreement with the microphone array measurements in a frequency range of 500-2000 Hz. This opens up the possibility...... to 1.9 million and angles of attack ranging from −10° to 14°. The emitted trailing noise from the aerofoils was measured with a microphone array at a distance of 1.6 m away from the aerofoil. The two-dimensional surface pressure field, which is considered the source of the emitted trailing edge noise...

  8. Chemical pressure effect in magnetic frustrated pyrochlore Nd2Pb2O7: A crystal-field analysis

    Science.gov (United States)

    Swarnakar, Debasish; Jana, Yatramohan; Alam, Jahangir; Nandi, Saikat

    2017-09-01

    Variation of chemical pressure at R-site due to substitution of nonmagnetic cation of varying size at the M-site makes a fine tuning between the crystal-field and molecular field to adopt exotic ground states in the frustrated magnetic R2M2O7 pyrochlore structures. Presence of larger cation at M-site increases the lattice parameter or nearest-neighbor bond distance between magnetic R-spins, and causes subtle changes to the local oxygen environment surrounding each R-ion, thereby reduces the chemical pressure at R-sites which leads to a dramatic change in the crystal-field and molecular field at R-site. To explore the effect of chemical pressure, the experimental results of powder magnetic susceptibility and isothermal magnetization of a geometrically frustrated compound, Nd2Pb2O7 containing largest cation, e.g. lead (Pb), at M4+-sites are simulated and analyzed employing a D3d crystal-field (CF) and anisotropic molecular field at R-sites in the self-consistent mean-field approach. The second-ordered axial parameter B20 and total CF splitting of the ground multiplet 4I9/2 of Nd3+-ions became the lowest among the isomorphic Nd-pyrochlore compounds, implying reduced effect of the crystal-field at Nd sites. Nd2Pb2O7 has strong [111] Ising anisotropy. Relative strength and values of the exchange tensor among nearest-neighbor Nd3+-spins in Nd2Pb2O7 and Nd2Zr2O7 result in a very close competition of anti-ferromagnetic and ferromagnetic interactions.

  9. Comparison of Iterative Methods for Computing the Pressure Field in a Dynamic Network Model

    DEFF Research Database (Denmark)

    Mogensen, Kristian; Stenby, Erling Halfdan; Banerjee, Srilekha

    1999-01-01

    In dynamic network models, the pressure map (the pressure in the pores) must be evaluated at each time step. This calculation involves the solution of a large number of nonlinear algebraic systems of equations and accounts for more than 80 of the total CPU-time. Each nonlinear system requires...

  10. Anisotropy of superconducting critical fields of {alpha}-(BEDT-TTF){sub 2}KHg(SCN){sub 4} under pressure

    Energy Technology Data Exchange (ETDEWEB)

    Jakob, S.; Neumaier, K.; Biberacher, W.; Kartsovnik, M. [Walther-Meissner-Inst., Garching (Germany)

    2007-07-01

    Our previous studies of the ''magnetic field - pressure - temperature'' phase diagram of the layered organic conductor {alpha}-(BEDT-TTF){sub 2}KHg(SCN){sub 4} have revealed an interesting interplay between a charge density wave (CDW) and a superconducting (SC) state. At a critical pressure of 2.5 kbar the CDW state is completely suppressed and a sharp transition into a SC state is observed below 100 mK. For pressures below 2.5 kbar there is a coexistence of the superconducting and CDW state, but this is likely a spatially inhomogenous state. The neighbouring of a CDW and SC state is an interesting situation and rises questions about the nature of the superconductivity. We have therefore investigated the anisotropy of the critical fields at a pressure slightly above the critical one. The experiments were performed in a dilution refrigerator down to 25 mK. Two-axes rotation of the magnetic field allowed the exact determination of the anisotropy parallel and perpendicular to the layers, but also the inplane anisotropy. (orig.)

  11. Intersubband optical absorption coefficients and refractive index changes in a graded quantum well under intense laser field: Effects of hydrostatic pressure, temperature and electric field

    Energy Technology Data Exchange (ETDEWEB)

    Ungan, F., E-mail: fungan@cumhuriyet.edu.tr [Department of Physics, Cumhuriyet University, 58140 Sivas (Turkey); Grupo de Materia Condensade-UdeA, Instituto de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín (Colombia); Restrepo, R.L. [Grupo de Materia Condensade-UdeA, Instituto de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín (Colombia); Escuela de Ingeniería de Antioquia AA 7516, Medellín (Colombia); Mora-Ramos, M.E. [Grupo de Materia Condensade-UdeA, Instituto de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín (Colombia); Facultad de Ciencias, Universidad Autonoma del Estado de Morelos, Ave. Universidad 1001, CP 62209, Cuernavaca, Morelos (Mexico); Morales, A.L.; Duque, C.A. [Grupo de Materia Condensade-UdeA, Instituto de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín (Colombia)

    2014-02-01

    The effects of hydrostatic pressure, temperature, and electric field on the optical absorption coefficients and refractive index changes associated with intersubband transition in a typical GaAs/Ga{sub 0.7}Al{sub 0.3}As graded quantum well under intense laser field have been investigated theoretically. The electron energy eigenvalues and the corresponding eigenfunctions of the graded quantum well are calculated within the effective mass approximation and envelope wave function approach. The analytical expressions of the optical properties are obtained using the compact density-matrix approach and the iterative method. The numerical results show that the linear and nonlinear optical properties depend strongly on the intense laser field and electric field but weakly on the hydrostatic pressure and temperature. Additionally, it has been found that the electronic and optical properties in a GaAs/Ga{sub 0.7}Al{sub 0.3}As graded quantum well under the intense laser field can be tuned by changing these external inputs. Thus, these results give a new degree of freedom in the devices applications.

  12. Assessment of Plasmodium falciparum resistance to ferroquine (SSR97193 in field isolates and in W2 strain under pressure

    Directory of Open Access Journals (Sweden)

    Pradines Bruno

    2006-02-01

    Full Text Available Abstract Background Ferroquine (FQ, or SSR97193, is a novel antimalarial drug currently in phase I clinical trials. FQ is a unique organometallic compound designed to overcome the chloroquine (CQ resistance problem. FQ revealed to be equally active on CQ-sensitive and CQ-resistant Plasmodium falciparum laboratory strains and field isolates. FQ is also curative on rodent malaria parasites. As FQ will be tested in patients, the potential for resistance to this drug was evaluated. Methods The relationship between CQ-resistant transporter gene genotype and susceptibility to FQ were studied in 33 Cambodian P. falciparum field isolates previously studied for their in vitro response to CQ. In parallel, the ability of the CQ-resistant strain W2, to become resistant to FQ under drug pressure was assessed. Results The IC50 values for FQ in field isolates were found to be unrelated to mutations occurring in the P. falciparum chloroquine resistance transporter (PfCRT or to the level of expression of the corresponding mRNA. In vitro, under a drug pressure of 100 nM of FQ, transient survival was observed in only one of two experiments. Conclusion Field isolates studies and experimental drug pressure experiments showed that FQ overcomes CQ resistance, which reinforces the potential of this compound as a new antimalarial drug.

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

    Science.gov (United States)

    Sarti, Giovanni; Rossi, Veronica; Amorosi, Alessandro

    2012-12-01

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

  14. The study of coastal ground surfaces to predict the ways of increasing efficiency of research mobile robots

    Science.gov (United States)

    Makarov, Vladimir; Kurkin, Andrey; Belyalov, Vladimir; Tyugin, Dmitry; Zezyulin, Denis

    2017-04-01

    The increase in spatial scales of studying coastal areas can be achieved by the use of mobile robotic systems (MRS) equipped with scanning equipment, video inspection system and positioning system. The project aims at increasing the capabilities for designing effective ground MRS through the use of advanced methods of forecasting characteristics of vehicle-terrain interaction in coastal zones, where hydrosphere, lithosphere, atmosphere and biosphere interact. In the period from 14 May to 18 June 2016 there was organized the expedition to Sakhalin Island for conducting full-scale testing autonomous MRS for coastal monitoring and forecasting marine natural disasters [Kurkin A.A., Zeziulin D.V., Makarov V.S., Zaitsev A.I., Belyaev A.M., Beresnev P.O., Belyakov V.V., Pelinovsky E.N., Tyugin D.Yu. Investigations of coastal areas of the Okhotsk sea using a ground mobile robot // Ecological systems and devices. 2016. No. 8. P. 11-17]. Within the framework of the expedition specific areas of terrain in the vicinity of Cape Svobodny were investigated (with the support of SRB AMR FEB RAS). Terrain areas were studied from the standpoint of possibility of the MRS movement. As a result of measuring all the necessary data on the physical-mechanical and geometric characteristics of the coastal zones, required to calculate the force factors acting on the MRS, and, accordingly, the parameters of its motion were received. The obtained data will be used for developing new statistical models of the physical-mechanical and geometrical characteristics of the coastal ground surfaces, creating methodology for assessing the efficiency and finding ways to optimize the design of the MRS.

  15. Study of Magnetic Field Behavior at Lower Pressure of Neon in the Axial Phase of INTI Plasma Focus

    Directory of Open Access Journals (Sweden)

    K.K.A. Devi

    2014-03-01

    Full Text Available The magnetic field distribution substantially affects mechanisms for the generation of radiation in Z-pinches. Investigation of the axial component of the magnetic field is one of the important problems in plasma focus studies. The designed magnetic probe is intended to use for the study of current sheet in INTI plasma focus device with energy of about 3.3 kJ. The measurements of the azimuthal component of the magnetic field on the INTI Plasma Focus operated at neon pressures below 1 Torr was carried out using a custom built calibrated magnetic probe. The probe was tested for neon gas under the various lower pressures (i.e., 0.1, 0.3, 0.5 and 0.7, 1, 2, 3, 5 torr etc.. It is observed that the time response of the designed probe is sufficient for the rise time of the magnetic field associated with the current in the axial phase. We also note that the small size of the designed probe is well suited to sense the magnetic field without perturbing the plasma unduly. The probe designed and constructed is also suitable to carryout measurements to obtain axial distributions of trajectory, average axial velocity and magnetic field of the current sheath at a certain radial distances along the axis of the tube.

  16. Synthesis and structure of NaNbO3 ceramic powders in ultrahigh pressure field

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The NaNbO3 powders were synthesized and their crystal structure changes were analyzed by ultrahigh pressure up to 6 GPa. The results indicate that the pure NaNbO3 powders can be synthesized at 300℃ under a pressure of 4 GPa, to significantly restrain the Na element volatilization compared with the traditional synthesis method. It is found that the crystal structure of synthesized NaNbO3 changes from low symmetry to high symmetry with the increase of the pressure.

  17. Working of spontaneously combustible coal seams with automatic air pressure regulation in the excavation field

    Energy Technology Data Exchange (ETDEWEB)

    Golik, A.S.; Churikov, Yu.V.; Troyan, N.P.

    1980-01-01

    A demonstration is made of the effectiveness of using an automatic air pressure control system during the working of spontaneously combustible coal seams in order to control endogenic fires and gas. 2 figures.

  18. Evaluation of the pressure field on a rigid body entering a quiescent fluid through particle image velocimetry

    Science.gov (United States)

    Panciroli, Riccardo; Porfiri, Maurizio

    2013-12-01

    The objective of this work is to verify the accuracy of indirect pressure measurement from particle image velocimetry in water entry problems. The pressure is evaluated by solving the incompressible Navier-Stokes equations, whose kinematic components are estimated from particle image velocimetry. We focus on the water entry of a rigid wedge, for which we explore variations of the entry velocity. Experimental results are verified through comparison with well-established analytical formulations based on potential flow theory. Our findings demonstrate the feasibility of accurately reconstructing the hydrodynamic pressure field over the entire duration of the impact. Along with a thorough experimental validation of the method, we also offer insight into experimentally relevant factors, such as the maximum resolved fluid velocity and the required spatial integration area.

  19. Impact of Spatial Resolution on Wind Field Derived Estimates of Air Pressure Depression in the Hurricane Eye

    Directory of Open Access Journals (Sweden)

    Linwood Jones

    2010-03-01

    Full Text Available Measurements of the near surface horizontal wind field in a hurricane with spatial resolution of order 1–10 km are possible using airborne microwave radiometer imagers. An assessment is made of the information content of the measured winds as a function of the spatial resolution of the imager. An existing algorithm is used which estimates the maximum surface air pressure depression in the hurricane eye from the maximum wind speed. High resolution numerical model wind fields from Hurricane Frances 2004 are convolved with various HIRAD antenna spatial filters to observe the impact of the antenna design on the central pressure depression in the eye that can be deduced from it.

  20. Characterization of magnetically confined low-pressure plasmas produced by an electromagnetic field in argon-acetylene mixtures

    Science.gov (United States)

    Makdessi, G. Al; Margot, J.; Clergereaux, R.

    2016-10-01

    Dust particles formation was investigated in magnetically confined low-pressure plasma produced in argon-acetylene mixtures. The plasma characteristics were measured in order to identify the species involved in the dust particles formation. Their dependence on the operating conditions including magnetic field intensity, acetylene fraction in the gas mixture and operating pressure was examined. In contrast with noble gases, in the presence of acetylene, the electron temperature increases with the magnetic field intensity, indicating additional charged particles losses in the plasma. Indeed, in these conditions, larger hydrocarbon ions are produced leading to the formation of dust particles in the plasma volume. The observed dependence of positive ion mass distribution and density and relative negative ion density on the operating parameters suggests that the dust particles are formed through different pathways, where negative and positive ions are both involved in the nucleation.

  1. Development and field application of a novel emulsion system O/W for well drilling of low pressure reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Arellano, J.; Ojeda, A.; Blanco, J.; Medina, N.; Gutierrez, X.; Carrasquero, M.; Briceno, H. [PDVSA (Venezuela)

    2011-07-01

    In Venezuela, there are important reserves of hydrocarbons in low pressure reservoirs but accessing to these reserves is a major challenge. This paper presents a new oil in water emulsion (O/W) system, using fatty acids and their salts as surfactant additives for use in such reservoirs, and the results obtained in field applications. Emulsions were prepared using two oil types and multiple salt (KCl) concentrations. Tests were then conducted to determine their thermal stability and return permeability percentage. Results showed good tolerance of high concentrations of KCl, as well as good stability under high temperatures and a good rheological behavior. The field test showed that the O/W emulsion system presents technological and cost advantages over other commercial technologies. This paper presented a new oil in water emulsion system which is a good alternative to water based fluids for well drilling in low pressure reservoirs.

  2. A large-area, flexible pressure sensor matrix with organic field-effect transistors for artificial skin applications

    Science.gov (United States)

    Someya, Takao; Sekitani, Tsuyoshi; Iba, Shingo; Kato, Yusaku; Kawaguchi, Hiroshi; Sakurai, Takayasu

    2004-07-01

    It is now widely accepted that skin sensitivity will be very important for future robots used by humans in daily life for housekeeping and entertainment purposes. Despite this fact, relatively little progress has been made in the field of pressure recognition compared to the areas of sight and voice recognition, mainly because good artificial "electronic skin" with a large area and mechanical flexibility is not yet available. The fabrication of a sensitive skin consisting of thousands of pressure sensors would require a flexible switching matrix that cannot be realized with present silicon-based electronics. Organic field-effect transistors can substitute for such conventional electronics because organic circuits are inherently flexible and potentially ultralow in cost even for a large area. Thus, integration of organic transistors and rubber pressure sensors, both of which can be produced by low-cost processing technology such as large-area printing technology, will provide an ideal solution to realize a practical artificial skin, whose feasibility has been demonstrated in this paper. Pressure images have been taken by flexible active matrix drivers with organic transistors whose mobility reaches as high as 1.4 cm2/V·s. The device is electrically functional even when it is wrapped around a cylindrical bar with a 2-mm radius.

  3. Effects of sound-field frequency modulation amplification on reducing teachers' sound pressure level in the classroom.

    Science.gov (United States)

    Sapienza, C M; Crandell, C C; Curtis, B

    1999-09-01

    Voice problems are a frequent difficulty that teachers experience. Common complaints by teachers include vocal fatigue and hoarseness. One possible explanation for these symptoms is prolonged elevations in vocal loudness within the classroom. This investigation examined the effectiveness of sound-field frequency modulation (FM) amplification on reducing the sound pressure level (SPL) of the teacher's voice during classroom instruction. Specifically, SPL was examined during speech produced in a classroom lecture by 10 teachers with and without the use of sound-field amplification. Results indicated a significant 2.42-dB decrease in SPL with the use of sound-field FM amplification. These data support the use of sound-field amplification in the vocal hygiene regimen recommended to teachers by speech-language pathologists.

  4. Tilting oil-water contact in the chalk of Tyra Field as interpreted from capillary pressure data

    DEFF Research Database (Denmark)

    Fabricius, Ida Lykke; Rana, M.A.

    2010-01-01

    -trends from logs were compared with normalized water saturation depth-trends predicted from capillary pressure core data. The ten wells lie close to a SW–NE cross section of the field. For the gas–oil contact, a free contact measured in one well corresponds to a practically horizontal contact interpreted from......The Tyra Field in the central North Sea is located in Palaeogene and Upper Cretaceous chalk. It contains a natural gas zone underlain by an oil leg. Based on analysis of logs and core data from ten wells drilled prior to the field being put into production, normalized water saturation depth...... logging data in the remaining wells. A westerly dipping oil–water contact was found from logging data. Comparison of the depth-wise trends in normalized water saturation among the different wells indicates a regional pattern: in the western side of the field, the trends correspond to a situation...

  5. ALOAD - a code to determine the concentrated forces equivalent with a distributed pressure field for a FEM analysis

    Directory of Open Access Journals (Sweden)

    Nicolae APOSTOLESCU

    2010-12-01

    Full Text Available The main objective of this paper is to describe a code for calculating an equivalent systemof concentrate loads for a FEM analysis. The tables from the Aerodynamic Department containpressure field for a whole bearing surface, and integrated quantities both for the whole surface andfor fixed and mobile part. Usually in a FEM analysis the external loads as concentrated loadsequivalent to the distributed pressure field are introduced. These concentrated forces can also be usedin static tests. Commercial codes provide solutions for this problem, but what we intend to develop isa code adapted to the user’s specific needs.

  6. Effect of a DC external electric field on the properties of a nonuniform microwave discharge in hydrogen at reduced pressures

    Energy Technology Data Exchange (ETDEWEB)

    Lebedev, Yu. A., E-mail: lebedev@ips.ac.ru; Krashevskaya, G. V.; Tatarinov, A. V.; Titov, A. Yu.; Epshtein, I. L. [Russian Academy of Sciences, Topchiev Institute of Petrochemical Synthesis (Russian Federation)

    2017-01-15

    The effect of a dc external electrical field on the properties of a highly nonuniform electrode microwave discharge in hydrogen at a pressure of 1 Torr was studied using optical emission spectroscopy and selfconsistent two-dimensional simulations. It is shown that the negative voltage applied to the antenna electrode with respect to the grounded chamber increases the discharge radiation intensity, while the positive voltage does not affect the discharge properties. The simulation results agree well with the experimental data.

  7. Growth and Form in Biology:Generation of the Plant Morphology by Spontaneous Symmetry Breaking Based on a Pressure Field

    Institute of Scientific and Technical Information of China (English)

    翁羽翔

    2004-01-01

    Considering the role of mechanical forces playing in the morphogenetic pattern formation, we propose a secondorder differential equation for the growth and form of plants based on the turgor pressure field at the organ and cellular level. The solutions can well describe various kinds of morphological features of flowers under certain hypotheses. The plant morphology is considered as the spontaneous symmetry breaking of a circular growing boundary, while the employed hypotheses are subjected to further experimental confirmation.

  8. Upper critical field of KFe2As2 under pressure: A test for the change in the superconducting gap structure

    Energy Technology Data Exchange (ETDEWEB)

    Taufour, Valentin [Ames Laboratory; Foroozani, Neda [Washington University; Tanatar, Makariy A. [Ames Laboratory; Lim, Jinhyuk [Washington University; Kaluarachchi, Udhara [Iowa State University; Kim, Stella K. [Ames Laboratory; Liu, Yong [Ames Laboratory; Lograsso, Thomas A. [Ames Laboratory; Kogan, Vladimir G. [Ames Laboratory; Prozorov, Ruslan [Ames Laboratory; Bud' ko, Sergey L. [Ames Laboratory; Schilling, James S. [Washington University; Canfield, Paul C. [Ames Laboratory

    2014-06-01

    We report measurements of electrical resistivity under pressure to 5.8 GPa, magnetization to 6.7 GPa, and ac susceptibility to 7.1 GPa in KFe2As2. The previously reported change of slope in the pressure dependence of the superconducting transition temperature Tc(p) at a pressure p*~1.8 GPa is confirmed, and Tc(p) is found to be nearly constant above p* up to 7.1 GPa. The T-p phase diagram is very sensitive to the pressure conditions as a consequence of the anisotropic uniaxial pressure dependence of Tc. Across p*, a change in the behavior of the upper critical field is revealed through a scaling analysis of the slope of Hc2 with the effective mass as determined from the A coefficient of the T2 term of the temperature-dependent resistivity. We show that this scaling provides a quantitative test for the changes of the superconducting gap structure and suggests the development of a kz modulation of the superconducting gap above p* as a most likely explanation.

  9. Using pressure transient analysis to improve well performance and optimize field development in compartmentalized shelf margin deltaic reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Badgett, K.L.; Crawford, G.E.; Mills, W.H. [and others

    1996-12-31

    BP Exploration`s Gulf of Mexico group developed procedures to conduct effective well tests on conventional production wells and employed them during the development drilling phase of the Mississippi Canyon 109 (MC109) field. Bottomhole pressure data were recorded during the initial few weeks of production. Typically, a 48 hour pressure buildup survey (surface shut-in) was obtained near the end of data acquisition. Data from these tests were analyzed for completion efficiency, reservoir flow capacity, reservoir heterogeneities, and drainage area. Initially wells were gravel packed for sand control, until buildup interpretations indicated skins greater than 20. Frac packing technology was then employed, and an immediate improvement was observed with skins dropping into the teens. Over a period of time frac packs were optimized using the test derived skins as a metric. Analysis of pressure data also played an important role in identifying reservoir compartmentalization. The two major reservoir horizons at MC 109 are interpreted as shelf margin deltas. However, each of these has distinctly different compartmentalization issues. The continuous character of the G Sand made it easier to define the depositional system and investigate reservoir compartmentalization issues using a combination of well log, 3D seismic, static pressure trends, and fluid information. In the more distal deltaic reservoirs of the J Sand however, complications with seismic amplitudes and a less reliable tie between wireline and seismic data required the use of pressure transient analysis to efficiently exploit the reservoir.

  10. Flow field and pressure loss analysis of junction and its structure optimization of aircraft hydraulic pipe system

    Institute of Scientific and Technical Information of China (English)

    Li Xin; Wang Shaoping

    2013-01-01

    The flow field in junction is complicated due to the ripple property of oil flow velocity and different frequencies of two pumps in aircraft.In this study,the flow fields of T-junction and Y-junction were analyzed using shear stress transport (SST) model in ANSYS/CFX software.The simulation results identified the variation rule of velocity peak in T-junction with different frequencies and phase-differences,meanwhile,the eddy and velocity shock existed in the corner of the T-junction,and the limit working state was obtained.Although the eddy disappeared in Y-junction,the velocity shock and pressure loss were still too big.To address these faults,an arc-junction was designed.Based on the flow fields of arc-junction,the eddy in the junction corner disappeared and the maximum of velocity peak declined compared to T-and Y-junction.Additionally,8 series of arcjunction with different radiuses were tested to get the variation rule of velocity peak.Through the computation of the pressure loss of three junctions,the arc-junction had a lowest loss value,and its pressure loss reached the minimum value when the curvature radius is 35.42 mm,meanwhile,the velocity shock has decreased in a low phase.

  11. Navier-Stokes flow field analysis of compressible flow in a high pressure safety relief valve

    Science.gov (United States)

    Vu, Bruce; Wang, Ten-See; Shih, Ming-Hsin; Soni, Bharat

    1993-12-01

    The objective of this study is to investigate the complex three-dimensional flowfield of an oxygen safety pressure relieve valve during an incident, with a computational fluid dynamic (CFD) analysis. Specifically, the analysis will provide a flow pattern that would lead to the expansion of the eventual erosion pattern of the hardware, so as to combine it with other findings to piece together a most likely scenario for the investigation. The CFD model is a pressure based solver. An adaptive upwind difference scheme is employed for the spatial discretization, and a predictor, multiple corrector method is used for the velocity-pressure coupling. The computational result indicated vortices formation near the opening of the valve which matched the erosion pattern of the damaged hardware.

  12. Numerical simulation of air flow field in high-pressure fan with splitter blades

    Institute of Scientific and Technical Information of China (English)

    Jianfeng LI; Junfu LU; Hai ZHANG; Qing LIU; Guangxi YUE

    2008-01-01

    For a deeper understanding of the flow char-acteristics in the high-pressure centrifugal blower of a fan of Model 9-26 with splitter blades, a three dimensional (3-D) numerical simulation of air flows in the fan was con-ducted with FLUENT software. The standard k-ε tur-bulent model and unstructured grids were used. The computational fluid dynamics (CFD) results showed that the performance of a fan could be improved by adding the splitter blades in the channel among the leaf blades. Under operational conditions, with the presence of splitter blades, the air flow rate of the fan increased about 5% and the total pressure at the outlet of the fan increased about 10% on average. It was also found that the length of the splitter blades affected the air flow and pressure drop. There is an optimal value for the length. The simulation results provide helpful information for improving the fan performance.

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

    Science.gov (United States)

    Nieuwendam, Alexandre; Ramos, Miguel; Vieira, Gonçalo

    2014-05-01

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

  14. French PWR 900 MWe pressure vessel surveillance neutron field characteristics TRIPOLI-3 calculations and experimental determination

    Energy Technology Data Exchange (ETDEWEB)

    Nimal, J.C.; Bourdet, L.; Zheng, S.H.; Vergnaud, T.; Kodeli, I. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. de Mecanique et de Technologie; Lloret, R.; Bevilacqua, A. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. des Reacteurs Experimentaux; Lefebvre, J.C. [Electricite de France (EDF), 69 - Villeurbanne (France)

    1994-12-31

    This paper presents an overview of the studies performed by CEA and EDF in the scope of the pressure vessel surveillance of the French nuclear power plants. The power plants are equipped with surveillance capsules, attached to the thermal shield. They contain the dosimeters and vessel material specimens for monitoring the effects of irradiation on the pressure vessel material. The Monte Carlo code TRIPOLI-3 is used with two nuclear data libraries to calculate the neutron flux, the steel damage and the dosimeter reaction rates, and takes into account the results of sensitivity/uncertainty calculations. 2 figs., 7 tabs., 10 refs.

  15. NASA's Habitat Demonstration Unit (HDU) Pressurized Excursion Module (PEM) In-Field Demonstration at Desert RATS 2010

    Science.gov (United States)

    Tri, Terry O.; Kennedy, Kriss J.; Toups, Larry; Gill, Tracy R.; Howe, A. Scott

    2011-01-01

    This paper describes the construction, assembly, subsystem integration, transportation, and field testing operations associated with the Habitat Demonstration Unit (HDU) Pressurized Excursion Module (PEM) and discusses lessons learned. In a one-year period beginning summer 2009, a tightly scheduled design-develop-build process was utilized by a small NASA "tiger team" to produce the functional HDU-PEM prototype in time to participate in the 2010 Desert Research and Technology Studies (Desert RATS) field campaign. The process required the coordination of multiple teams, subcontractors, facility management and safety staff. It also required a well-choreographed material handling and transportation process to deliver the finished product from the NASA-Johnson Space Center facilities to the remote Arizona desert locations of the field test. Significant findings of this paper include the team s greater understanding of the HDU-PEM s many integration issues and the in-field training the team acquired which will enable the implementation of the next-generation of improvements and development of high-fidelity field operations in a harsh environment. The Desert RATS analog environment is being promoted by NASA as an efficient means to design, build, and integrate multiple technologies in a mission architecture context, with the eventual goal of evolving the technologies into robust flight hardware systems. The HDU-PEM in-field demonstration at Desert RATS 2010 provided a validation process for the integration team, which has already begun to retool for the 2011 field tests that require an adapted architecture.

  16. The Covariance of Scalar Fields Scattered by Pressure-Release Randomly Rough Surfaces.

    Science.gov (United States)

    1987-12-01

    The Mean Scattered Pressure .- The surfaces to be dealt with will be random stationary, ’. described by "(x",y"). "(x",y") is a sample of a...developed in Chapter 3 when the surface involved is the fully developed, non-directional ocean spectrum -see Appendix. For convience we list the most

  17. Unsteady Correlation between pressure and Temperature Field on Impinging Plate for Dual Underexpanded Jets

    Institute of Scientific and Technical Information of China (English)

    Minoru YAGA; Hiroyuki HIGA; MATSUDA; lzuru SENAHA

    2009-01-01

    eady behavior of the jets. After the confirmation of the cor-relation, a simple way to find the severe fluctuating region can be provided according to the two dimensional un-steady temperature images without a lot of unsteady pressure measurements.

  18. Consumer acceptance of high-pressure processing and pulsed-electric-field

    DEFF Research Database (Denmark)

    Olsen, Nina Veflen; Grunert, Klaus G.; Sonne, Anne-Mette

    2010-01-01

    has to offer, do not necessarily guarantee the success of a product in the market place. Consumer acceptance depends on whether consumers perceive that there are specific benefits associated with the product. This review focuses specifically on how high-pressure processing (HPP) and pulsed...

  19. Cohesive zone laws for void growth — II. Numerical field projection of elasto-plastic fracture processes with vapor pressure

    Science.gov (United States)

    Chew, Huck Beng; Hong, Soonsung; Kim, Kyung-Suk

    2009-08-01

    Modeling ductile fracture processes using Gurson-type cell elements has achieved considerable success in recent years. However, incorporating the full mechanisms of void growth and coalescence in cohesive zone laws for ductile fracture still remains an open challenge. In this work, a planar field projection method, combined with equilibrium field regularization, is used to extract crack-tip cohesive zone laws of void growth in an elastic-plastic solid. To this end, a single row of void-containing cell elements is deployed directly ahead of a crack in an elastic-plastic medium subjected to a remote K-field loading; the macroscopic behavior of each cell element is governed by the Gurson porous material relation, extended to incorporate vapor pressure effects. A thin elastic strip surrounding this fracture process zone is introduced, from which the cohesive zone variables can be extracted via the planar field projection method. We show that the material's initial porosity induces a highly convex traction-separation relationship — the cohesive traction reaches the peak almost instantaneously and decreases gradually with void growth, before succumbing to rapid softening during coalescence. The profile of this numerically extracted cohesive zone law is consistent with experimentally determined cohesive zone law in Part I for multiple micro-crazing in HIPS. In the presence of vapor pressure, both the cohesive traction and energy are dramatically lowered; the shape of the cohesive zone law, however, remains highly convex, which suggests that diffusive damage is still the governing failure mechanism.

  20. Differences in rates of decrease of environmental radiation dose rates by ground surface property in Fukushima City after the Fukushima Daiichi nuclear power plant accident.

    Science.gov (United States)

    Kakamu, Takeyasu; Kanda, Hideyuki; Tsuji, Masayoshi; Kobayashi, Daisuke; Miyake, Masao; Hayakawa, Takehito; Katsuda, Shin-ichiro; Mori, Yayoi; Okouchi, Toshiyasu; Hazama, Akihiro; Fukushima, Tetsuhito

    2013-01-01

    After the Great East Japan Earthquake on 11 March 2011, the environmental radiation dose in Fukushima City increased. On 11 April, 1 mo after the earthquake, the environmental radiation dose rate at various surfaces in the same area differed greatly by surface property. Environmental radiation measurements continue in order to determine the estimated time to 50% reduction in environmental radiation dose rates by surface property in order to make suggestions for decontamination in Fukushima. The measurements were carried out from 11 April to 11 November 2011. Forty-eight (48) measurement points were selected, including four kinds of ground surface properties: grass (13), soil (5), artificial turf (7), and asphalt (23). Environmental radiation dose rate was measured at heights of 100 cm above the ground surface. Time to 50% reduction of environmental radiation dose rates was estimated for each ground surface property. Radiation dose rates on 11 November had decreased significantly compared with those on 11 April for all surface properties. Artificial turf showed the longest time to 50% reduction (544.32 d, standard error: 96.86), and soil showed the shortest (213.20 d, standard error: 35.88). The authors found the environmental radiation dose rate on artificial materials to have a longer 50% reduction time than that on natural materials. These results contribute to determining an order of priority for decontamination after nuclear disasters.

  1. Crystallization of spin superlattices with pressure and field in the layered magnet SrCu2(BO3)2

    Science.gov (United States)

    Haravifard, S.; Graf, D.; Feiguin, A. E.; Batista, C. D.; Lang, J. C.; Silevitch, D. M.; Srajer, G.; Gaulin, B. D.; Dabkowska, H. A.; Rosenbaum, T. F.

    2016-01-01

    An exact mapping between quantum spins and boson gases provides fresh approaches to the creation of quantum condensates and crystals. Here we report on magnetization measurements on the dimerized quantum magnet SrCu2(BO3)2 at cryogenic temperatures and through a quantum-phase transition that demonstrate the emergence of fractionally filled bosonic crystals in mesoscopic patterns, specified by a sequence of magnetization plateaus. We apply tens of Teslas of magnetic field to tune the density of bosons and gigapascals of hydrostatic pressure to regulate the underlying interactions. Simulations help parse the balance between energy and geometry in the emergent spin superlattices. The magnetic crystallites are the end result of a progression from a direct product of singlet states in each short dimer at zero field to preferred filling fractions of spin-triplet bosons in each dimer at large magnetic field, enriching the known possibilities for collective states in both quantum spin and atomic systems. PMID:27320787

  2. Hybrid Simulation of Supersonic Flow of Weakly Ionized Plasma along Open Field Magnetic Line Effect of Background Pressure

    Science.gov (United States)

    Laosunthara, Ampan; Akatsuka, Hiroshi

    2016-09-01

    In previous study, we experimentally examined physical properties of supersonic flow of weakly ionized expanding arc-jet plasma through an open magnetic field line (Bmax 0.16T). We found supersonic velocity of helium plasma up to Mach 3 and the space potential drop at the end of the magnets. To understand the plasma in numerical point of view, the flows of ion and neutral are treated by particle-based Direct Simulation Monte Carlo (DSMC) method, electron is treated as a fluid. The previous numerical study, we assumed 2 conditions. Ion and electron temperatures were the same (LTE condition). Ion and electron velocities were the same (current-free condition). We found that ion velocity decreased by collision with residual gas molecules (background pressure). We also found that space potential changing with background pressure. In other words, it was indicated that electric field exists and the current-free assumption is not proper. In this study, we add electron continuity and electron momentum equations to obtain electron velocity and space potential. We find that space potential changing with background pressure slightly. It is indicated that electron is essential to space potential formation than ion.

  3. LIGHT PRESSURE: Theoretical study of the light pressure force acting on a spherical dielectric particle of an arbitrary size in the interference field of two plane monochromatic electromagnetic waves

    Science.gov (United States)

    Guzatov, D. V.; Gaida, L. S.; Afanas'ev, Anatolii A.

    2008-12-01

    The light pressure force acting on a spherical dielectric particle in the interference field of two plane monochromatic electromagnetic waves is studied in detail for different particle radii and angles of incidence of waves.

  4. Remote field eddy current technique for gap measurement of horizontal flux detector guide tube in pressurized heavy water reactor

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dong Hoon; Jung, Hyun Kyu; Yang, Dong Ju; Cheong, Yong Moo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2004-11-15

    The fuel channels including the pressure tube(PT) and the calandria tube(CT) are important components of the pressurized heavy water reactor(PHWR). A sagging of fuel channel increases by heat and radiation exposure with the increasing operation time. The contact of fuel channel to the Horizontal flux Detector(HFD) guide tube is needed for the power plant safety. In order to solve this safety issue, the electromagnetic technique was applied to measure the status of the guide tube. The Horizontal flux Detector(HFD) guide tube and the Calandria tube(CT) in the Pressurized Heavy Water Reactor(PHWR) are cross-aligned horizontally. The remote field eddy current(RFEC) technology is applied for gap measurement between the HFD guide tube and the CT HFD guide tube can be detected by inserting the RFEC probe into pressure tube(PT) at the crossing point directly. The RFEC signals using the volume integral method(VIM) were simulated for obtaining the optimal inspection parameters. This paper shows that the simulated eddy current signals and the experimental results in variance with the CT/HFD gap.

  5. CAPILLARY PRESSURE/MERCURY INJECTION ANALYSIS: CHEROKEE AND BUG FIELDS, SAN JUAN COUNTY, UTAH

    Energy Technology Data Exchange (ETDEWEB)

    Thomas C. Chidsey Jr; David E. Eby

    2003-12-01

    Over 400 million barrels (64 million m{sup 3}) of oil have been produced from the shallow-shelf carbonate reservoirs in the Pennsylvanian (Desmoinesian) Paradox Formation in the Paradox Basin, Utah and Colorado. With the exception of the giant Greater Aneth field, the other 100 plus oil fields in the basin typically contain 2 to 10 million barrels (0.3-1.6 million m{sup 3}) of original oil in place. Most of these fields are characterized by high initial production rates followed by a very short productive life (primary), and hence premature abandonment. Only 15 to 25 percent of the original oil in place is recoverable during primary production from conventional vertical wells. An extensive and successful horizontal drilling program has been conducted in the giant Greater Aneth field. However, to date, only two horizontal wells have been drilled in small Ismay and Desert Creek fields. The results from these wells were disappointing due to poor understanding of the carbonate facies and diagenetic fabrics that create reservoir heterogeneity. These small fields, and similar fields in the basin, are at high risk of premature abandonment. At least 200 million barrels (31.8 million m{sup 3}) of oil will be left behind in these small fields because current development practices leave compartments of the heterogeneous reservoirs undrained. Through proper geological evaluation of the reservoirs, production may be increased by 20 to 50 percent through the drilling of low-cost single or multilateral horizontal legs from existing vertical development wells. In addition, horizontal drilling from existing wells minimizes surface disturbances and costs for field development, particularly in the environmentally sensitive areas of southeastern Utah and southwestern Colorado.

  6. Correlation of the vapor pressure isotope effect with molecular force fields in the liquid state

    Energy Technology Data Exchange (ETDEWEB)

    Pollin, J.S.; Ishida, T.

    1976-07-01

    The present work is concerned with the development and application of a new model for condensed phase interactions with which the vapor pressure isotope effect (vpie) may be related to molecular forces and structure. The model considers the condensed phase as being represented by a cluster of regularly arranged molecules consisting of a central molecule and a variable number of molecules in the first coordination shell. The methods of normal coordinate analysis are used to determine the modes of vibration of the condensed phase cluster from which, in turn, the isotopic reduced partition function can be calculated. Using the medium cluster model, the observed vpie for a series of methane isotopes has been successfully reproduced with better agreement with experiment than has been possible using the simple cell model. We conclude, however, that insofar as the medium cluster model provides a reasonable picture of the liquid state, the vpie is not sufficiently sensitive to molecular orientation to permit an experimental determination of intermolecular configuration in the condensed phase through measurement of isotopic pressure ratios. The virtual independence of vapor pressure isotope effects on molecular orientation at large cluster sizes is a demonstration of the general acceptability of the cell model assumptions for vpie calculations.

  7. Application of BCM-LES model to flow and pressure fields over urban roughness

    Science.gov (United States)

    Tamura, Tetsuro; Kawai, Hidenori; Bale, Rahul; Onishi, Keiji; Tsubokura, Makoto

    2016-11-01

    BCM (Building Cube Method) enables high-resolution CFD (Computational Fluid Dynamics) simulation by high parallelization performance. This study discusses the applicability of LES (Large Eddy Simulation) based on BCM to prediction of wind velocity and pressure around various building blocks in urban area. First, we validate the computed results of flows past 3D square cylinder in turbulent boundary layer. Fundamental accuracy of the surface pressure distribution on square cylinder is investigated by high-resolution BCM simulation with IBM (Immersed Boundary Method). Next, the BCM is applied to flow simulation of real urban area (Domain size: 25x12km). As a result of this simulation, the development process of urban boundary layer from coastal area to Tokyo central area is examined. Accordingly we show the present numerical model based on BCM-LES can represent sufficiently spatially fine structures and temporally unsteady fluctuations of turbulent flows with good accuracy. It is clarified that the complex pressure distributions acting on the buildings have been also reproduced from the sense of wind-resistance design of buildings in cities

  8. Effects of stator bending on pressure field and loss of transonic turbine stage

    Institute of Scientific and Technical Information of China (English)

    WANG Kai; ZHOU Xun; WANG Zhong-qi

    2009-01-01

    To study effects of the upstream flow field changing on the downstream flow field of transonic turbine, different three-dimensional bowed blades, which are the stator blades of transonic turbine stage, were designed in this paper. And then numerical calculations were carried out. The effects on downstream flow field were studied and analyzed in detail. Results show that, at the middle of stator blades, although the increasing Mach number causes the increase of shock-wave strength and friction, the middle flow field of downstream rotors is improved obviously. It is an important change in transonic condition. This causes the loss of the rotor's middie part decreased greatly. Correspondingly, efficiency of the whole transonic stage can be increased.

  9. Low-field-enhanced unusual hysteresis produced by metamagnetism of the MnP clusters in the insulating CdGe P2 matrix under pressure

    Science.gov (United States)

    Arslanov, T. R.; Arslanov, R. K.; Kilanski, L.; Chatterji, T.; Fedorchenko, I. V.; Emirov, R. M.; Ril, A. I.

    2016-11-01

    Hydrostatic pressure studies of the isothermal magnetization and volume changes up to 7 GPa of magnetic composite containing MnP clusters in an insulating CdGe P2 matrix are presented. Instead of alleged superparamagnetic behavior, a pressure-induced magnetization process was found at zero magnetic field, showing gradual enhancement in a low-field regime up to H ⩾5 kOe. The simultaneous application of pressure and magnetic field reconfigures the MnP clusters with antiferromagnetic alignment, followed by onset of a field-induced metamagnetic transition. An unusual hysteresis in magnetization after pressure cycling is observed, which is also enhanced by application of the magnetic field, and indicates reversible metamagnetism of MnP clusters. We relate these effects to the major contribution of structural changes in the composite, where limited volume reduction by 1.8% is observed at P ˜5.2 GPa.

  10. Phase Field Theory and Analysis of Pressure-Shear Induced Amorphization and Failure in Boron Carbide Ceramic

    Directory of Open Access Journals (Sweden)

    John D. Clayton

    2014-07-01

    Full Text Available A nonlinear continuum phase field theory is developed to describe amorphization of crystalline elastic solids under shear and/or pressure loading. An order parameter describes the local degree of crystallinity. Elastic coefficients can depend on the order parameter, inelastic volume change may accompany the transition from crystal to amorphous phase, and transitional regions parallel to bands of amorphous material are penalized by interfacial surface energy. Analytical and simple numerical solutions are obtained for an idealized isotropic version of the general theory, for an element of material subjected to compressive and/or shear loading. Solutions compare favorably with experimental evidence and atomic simulations of amorphization in boron carbide, demonstrating the tendency for structural collapse and strength loss with increasing shear deformation and superposed pressure.

  11. The application of super wavelet finite element on temperature-pressure coupled field simulation of LPG tank under jet fire

    Science.gov (United States)

    Zhao, Bin

    2015-02-01

    Temperature-pressure coupled field analysis of liquefied petroleum gas (LPG) tank under jet fire can offer theoretical guidance for preventing the fire accidents of LPG tank, the application of super wavelet finite element on it is studied in depth. First, review of related researches on heat transfer analysis of LPG tank under fire and super wavelet are carried out. Second, basic theory of super wavelet transform is studied. Third, the temperature-pressure coupled model of gas phase and liquid LPG under jet fire is established based on the equation of state, the VOF model and the RNG k-ɛ model. Then the super wavelet finite element formulation is constructed using the super wavelet scale function as interpolating function. Finally, the simulation is carried out, and results show that the super wavelet finite element method has higher computing precision than wavelet finite element method.

  12. The reaction-field effect on the chemical potentials of polar aprotic non-aromatic liquids 1. Vapour pressure

    Science.gov (United States)

    Rosseinsky, D. R.; Stead, K.; Mowforth, C. W.

    1998-10-01

    The reaction field for the interaction of a molecule with its identical neighbours is shown to be a major determinant of the chemical potential of many dipolar liquids. The electrostatic potential w, derived for immersion of the dipolar molecule in its own kind, and notably comprising solely static and hf permittivities, is equated with the difference between the polar-liquid chemical potential and that of an isostructural non-polar hydrocarbon. For all the 26 non-aromatic Onsager liquids for which the requisite data are available, acceptable conformity is established of the vapour pressure calculated from w with that observed, fluorocarbons excepted. If w turns out to be small, vapour pressures of (these 12) dipolars approximate quite closely to those of the isostructural non-polars, as expected. For ketones and nitroalkanes varied-temperature data are available and well reproduced via w: thus calculated vaporization enthalpies equal the observed.

  13. Field-Activated, Pressure-Assisted Synthesis of Ultra-hard, Super-Abrasive AlMgB14

    Science.gov (United States)

    Liu, Wen; Wu, Yin-tao; Mao, Shu-hong; Pan, Rui-li; Zhang, Jing; Zhang, Tie-ming

    2013-04-01

    Mechanical alloying (MA) and the field-activated and pressure-assisted in situ synthesis (FAPAS) were combined to prepare the ultra-hard and super-abrasive AlMgB14 with the characteristics of fast heating-up, high efficiency, and low energy cost. Such preparations using the elemental constituents, such as Al, Mg, and B, were performed at a vacuum annealed temperature of 1500 °C under a pressure of 60 MPa. The resultant ceramics were characterized by SEM, EDS, and XRD. It was shown that the samples contained uniform AlMgB14, and the maximum hardness on the sample surface may reach 32.5 GPa. Furthermore, a second experiment was performed, in which MgH2 was used as one of the starting materials instead of elemental Mg, but this approach did not produce AlMgB14.

  14. Fielding the magnetically applied pressure-shear technique on the Z accelerator (completion report for MRT 4519).

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, C. Scott; Haill, Thomas A.; Dalton, Devon Gardner; Rovang, Dean Curtis; Lamppa, Derek C.

    2013-09-01

    The recently developed Magnetically Applied Pressure-Shear (MAPS) experimental technique to measure material shear strength at high pressures on magneto-hydrodynamic (MHD) drive pulsed power platforms was fielded on August 16, 2013 on shot Z2544 utilizing hardware set A0283A. Several technical and engineering challenges were overcome in the process leading to the attempt to measure the dynamic strength of NNSA Ta at 50 GPa. The MAPS technique relies on the ability to apply an external magnetic field properly aligned and time correlated with the MHD pulse. The load design had to be modified to accommodate the external field coils and additional support was required to manage stresses from the pulsed magnets. Further, this represents the first time transverse velocity interferometry has been applied to diagnose a shot at Z. All subsystems performed well with only minor issues related to the new feed design which can be easily addressed by modifying the current pulse shape. Despite the success of each new component, the experiment failed to measure strength in the samples due to spallation failure, most likely in the diamond anvils. To address this issue, hydrocode simulations are being used to evaluate a modified design using LiF windows to minimize tension in the diamond and prevent spall. Another option to eliminate the diamond material from the experiment is also being investigated.

  15. Field and pressure response of Yb compounds close to a quantum critical point

    Indian Academy of Sciences (India)

    C Seuring; E W Scheidt; E Bauer

    2002-05-01

    YbCu5-Al provides the possibility to tune ground state properties by a change of the valence due to the Cu/Al substitution, by pressure as well as by the application of a magnetic field. Near to the critical concentration cr ≈ 1.5 non-Fermi-liquid properties (NFL) are obvious, obeying hyperscaling. If magnetic order sets in for >1.5, the application of moderate magnetic fields quenches order and again NFL features become evident. Hyperscaling in this case indicates strongly interacting spin fluctuations.

  16. The Pressure Field Measurement for Researching Inducer Flow of Booster Rocket Engine Turbopump

    Directory of Open Access Journals (Sweden)

    N. S. Dorosh

    2014-01-01

    Full Text Available When designing a feed system for modern main rocket engine development, designers have to pay special attention to energy efficiency of units and their reliability. One of the most important conditions of reliability is to provide non-cavitation operation of the main turbo-pump, which is impossible without using the booster turbo-pumps, considering the current levels of pressure in the combustion chamber. Thanks to high suction properties and processability, axial inducers with screw geometry became the most widely used in booster turbo-pumps. At the same time, the flow in the inducers of progressive geometry has complex spatial nature that makes their designing and detailed flow studying to be a difficult task.Based on the need of detailed understanding the flow structure in inducer channels a number of investigation methods are considered, including: analytical calculation, visual research methods, direct flow measurement, and numerical simulation. Analysis of the characteristics of each method shows the need to combine several methods to achieve the best results. Using a numerical simulation becomes the most effective strategy to obtain a wide range of data and confirm their authenticity by experimental measurements at characteristic points. The features of such kind of measurements in the inducer flow and measuring device requirements are considered.Based on this, an original design experimental booster turbo-pump, equipped with a pressure measuring system behind the inducer and automatic unloader device simulator is developed. Using these systems a radial pressure diagram of inducer flow as well as axial the force acting on the inducer can be experimentally obtained. It is shown that the offered measuring system satisfies those requirements and provides data at the various operation modes of the booster turbopump unit. A developed test program allows us to obtain required data: the pressure values in the flow behind inducer and axial force

  17. First-order antiferro-ferromagnetic transition in Fe(49)(Rh(0.93)Pd(0.07))(51) under simultaneous application of magnetic field and external pressure.

    Science.gov (United States)

    Kushwaha, Pallavi; Bag, Pallab; Rawat, R; Chaddah, P

    2012-03-07

    A magnetic field-pressure-temperature (H-P-T) phase diagram for first-order antiferromagnetic (AFM) to ferromagnetic (FM) transitions in Fe(49)(Rh(0.93)Pd(0.07))(51) has been constructed using resistivity measurements under simultaneous application of magnetic field (up to 8 T) and pressure (up to 20 kbar). The temperature dependence of resistivity (ρ-T) shows that the width of the transition and the extent of hysteresis decreases with pressure and increases with magnetic field. By exploiting opposing trends of dT(N)/dP and dT(N)/dH (where T(N) is the first-order transition temperature), the relative effects of temperature, magnetic field and pressure on disorder-broadened first-order transitions has been studied. For this, a set of H and P values are chosen for which T(N)(H(1),P(1)) = T(N)(H(2),P(2)). Measurements for such combinations of H and P show that the temperature dependence of resistivity is similar, i.e. the broadening (in temperature) of transition as well as the extent of hysteresis remains independent of H and P. Isothermal magnetoresistance measurements under various constant pressures show that even though the critical field required for AFM-FM transition depends on applied pressure, the extent of hysteresis as well as transition width (in magnetic field) remains constant with varying pressure.

  18. Experimental Verification and Research for the Distortion in the Integrated Frequency Responses of the High-Pressure Sealed Cabin and Magnetic Field Sensor

    Institute of Scientific and Technical Information of China (English)

    Deng Ming; Wei Wenbo; Jin Sheng; Ye Gaofeng; Zhang Qisheng; Jing Jian'en

    2007-01-01

    Although magnetotelluric sounding method applied to the land is advanced, there are many difficulties when it is applied to marine environment, one of which is how to lay magnetic field sensors down to the seafloor to complete measurements. To protect the magnetic field sensors from intense erosion and high pressure, suitable high-pressure sealed cabins must be designed to load them. For the consideration of magnetic measurement and marine operation, the sealed pressure cabin should be nonmagnetic and transportable. Among all optional materials, LC4 super-hard aluminum alloy has the highest performance of price/quality ratio to make the sealed pressure cabin. However, it does not mean that the high-pressure sealed cabin made using LC4 will be perfect in performance. In fact, because of its weak magnetism, the pressure cabin made using LC4 has distorting effect on frequency responses of the magnetic field sensors sealed in it. This distorting effect does not affect the use of the magnetic field sensor,but if we want to eliminate its effect, we should study it by experimental measurements. In our experiment tests, frequency sweep magnetic field as excitation signal was used, and then responses of the magnetic field sensor before and after being loaded into the high-pressure sealed cabin were measured. Finally,normalized abnormal curves for the frequency responses were obtained, through which we could show how the high-pressure sealed cabin produces effects on the responses of the magnetic field sensor. Experimental results suggest that the response distortion induced by the sealed pressure cabin appears on mid- and high-frequency areas. Using experimental results as standardization data, the frequency responses collected from seafloor magnetotelluric measurements can be corrected to restore real information about the seafloor field source.

  19. Consumer perception of the use of high-pressure processing and pulsed electric field technologies in food production

    DEFF Research Database (Denmark)

    Nielsen, Henriette Boel; Sonne, Anne-Mette; Grunert, Klaus G.

    2009-01-01

    on consumer attitudes towards high-pressure processing (HPP) and pulsed electric field (PEF) processing of food was carried out. In all 97 adults between 20 and 71 years of age participated in 12 focus groups conducted in Slovenia, Hungary, Serbia, Slovakia, Norway and Denmark using a common guideline...... showed that environmental friendliness and the more natural products were seen as the main advantages, while they were concerned about body and health, the higher price of the products, the lack of information about the technologies and a general scepticism. The study also shows that North European...

  20. Field Performance of Cowpea Genotypes Grown under Virus Pressure in Puerto Rico

    Science.gov (United States)

    Cowpea [Vigna unguiculata (L.) Walp.] is an important grain legume in many regions of the tropics. However, viral diseases, particularly Cucumber mosaic virus (CMV) and Blackeye cowpea mosaic virus (BlCMV), can be a limiting factor in cowpea production. We evaluated in replicated field plots and un...

  1. Effects of a carbon convection field on large diamond growth under high-pressure high-temperature conditions

    Institute of Scientific and Technical Information of China (English)

    Hu Mei-Hua; Li Shang-Sheng; Ma Hong-An; Su Tai-Chao; Li Xiao-Lei; Hu Qiang; Jia Xiao-Peng

    2012-01-01

    Large diamond crystals were successfully synthesized by a FeNi-C system using the temperature gradient method under high-pressure high-temperature conditions.The assembly of the growth cell was improved and the growth process of diamond was investigated.Effects of the symmetry of the carbon convection field around the growing diamond crystal were investigated systematically by adjusting the position of the seed crystal in the melted catalyst/solvent.The results indicate that the morphologies and metal inclusion distributions of the synthetic diamond crystals vary obviously in both symmetric and non-symmetric carbon convection fields with temperature.Moreover,the finite element method was applied to analyze the carbon convection mode of the melted catalyst/solvent around the diamond crystal.This work is helpful for understanding the growth mechanism of diamond.

  2. Validity and reliability of pressure-measurement insoles for vertical ground reaction force assessment in field situations.

    Science.gov (United States)

    Koch, Markus; Lunde, Lars-Kristian; Ernst, Michael; Knardahl, Stein; Veiersted, Kaj Bo

    2016-03-01

    This study aimed to test the validity and reliability of pressure-measurement insoles (medilogic® insoles) when measuring vertical ground reaction forces in field situations. Various weights were applied to and removed from the insoles in static mechanical tests. The force values measured simultaneously by the insoles and force plates were compared for 15 subjects simulating work activities. Reliability testing during the static mechanical tests yielded an average interclass correlation coefficient of 0.998. Static loads led to a creeping pattern of the output force signal. An individual load response could be observed for each insole. The average root mean square error between the insoles and force plates ranged from 6.6% to 17.7% in standing, walking, lifting and catching trials and was 142.3% in kneeling trials. The results show that the use of insoles may be an acceptable method for measuring vertical ground reaction forces in field studies, except for kneeling positions.

  3. The unsteady pressure field and the aerodynamic performances of a Savonius rotor based on the discrete vortex method

    Energy Technology Data Exchange (ETDEWEB)

    Afungchui, David [University of Buea, Faculty of Science, Department of Physics, UB Street, PO Box 63, Molyko, Buea, South West (Cameroon); Kamoun, Baddreddinne; Helali, Ali; Ben Djemaa, Abdellatif [Faculte des Sciences de Sfax, Departement de Physique, Laboratoire de Physique, Appliquee (L.P.A.), Sfax (Tunisia)

    2010-01-15

    The aim of this paper is to numerically explore the non-linear two-dimensional unsteady potential flow over a Savonius rotor and to develop a code for predicting its aerodynamics performances. In the model developed, the rotor is represented in a median plane by two semicircles, displaced along their common diameter. The two semicircles can be considered to produce lifting effects. As a result, they are modelled by a collection of discrete vortices on their contours. The flow field is then governed by the Laplace equation. The versatile Neumann boundary condition, applied over the contour of the semicircles and the Kutta Joukowsky condition applied at the four extremities of the semicircles have been used in the modelling. The torque distribution of the stationary rotor and the unsteady pressure field on the blades of the rotating rotor, predicted by the code developed, have been compared and validated by some experimental data. (author)

  4. Crystal-field excitations in PrAl sub 3 and NdAl sub 3 at ambient and elevated pressure

    CERN Document Server

    Straessle, T; Rusz, J; Janssen, S; Juranyi, F; Sadykov, R; Furrer, A

    2003-01-01

    The crystal fields (CFs) of the binary rare-earth compounds PrAl sub 3 and NdAl sub 3 have been examined at ambient pressure by means of inelastic neutron scattering. The CF of the latter compound has also been measured under hydrostatic pressure (p = 0.84 GPa). The observed substantial changes of the CF under pressure are discussed within the framework of first-principles density functional theory calculations.

  5. Four-dimensional equation of motion for viscous compressible and charged fluid with regard to the acceleration field, pressure field and dissipation field

    CERN Document Server

    Fedosin, Sergey G

    2016-01-01

    From the principle of least action the equation of motion for viscous compressible and charged fluid is derived. The viscosity effect is described by the 4-potential of the energy dissipation field, dissipation tensor and dissipation stress-energy tensor. In the weak field limit it is shown that the obtained equation is equivalent to the Navier-Stokes equation. The equation for the power of the kinetic energy loss is provided, the equation of motion is integrated, and the dependence of the velocity magnitude is determined. A complete set of equations is presented, which suffices to solve the problem of motion of viscous compressible and charged fluid in the gravitational and electromagnetic fields.

  6. Development of automated welding process for field fabrication of thick walled pressure vessels. Fourth quarter technical progress report for period ending September 30, 1979

    Energy Technology Data Exchange (ETDEWEB)

    None

    1979-01-01

    Progress in developing an automated welding process for the field fabrication of thick walled pressure vessels is reported. Plans for the demonstration facility, for nondestructive testing, and for the procurement of materials are discussed. (LCL)

  7. Theoretical and numerical studies of crack initiation and propagation in rock masses under freezing pressure and far-field stress

    Directory of Open Access Journals (Sweden)

    Yongshui Kang

    2014-10-01

    Full Text Available Water-bearing rocks exposed to freezing temperature can be subjected to freeze–thaw cycles leading to crack initiation and propagation, which are the main causes of frost damage to rocks. Based on the Griffith theory of brittle fracture mechanics, the crack initiation criterion, propagation direction, and crack length under freezing pressure and far-field stress are analyzed. Furthermore, a calculation method is proposed for the stress intensity factor (SIF of the crack tip under non-uniformly distributed freezing pressure. The formulae for the crack/fracture propagation direction and length of the wing crack under freezing pressure are obtained, and the mechanism for coalescence of adjacent cracks is investigated. In addition, the necessary conditions for different coalescence modes of cracks are studied. Using the topology theory, a new algorithm for frost crack propagation is proposed, which has the capability to define the crack growth path and identify and update the cracked elements. A model that incorporates multiple cracks is built by ANSYS and then imported into FLAC3D. The SIFs are then calculated using a FISH procedure, and the growth path of the freezing cracks after several calculation steps is demonstrated using the new algorithm. The proposed method can be applied to rocks containing fillings such as detritus and slurry.

  8. Watching the wind: seismic data contamination at long-periods due to atmospheric pressure-field-induced tilting

    Science.gov (United States)

    de Angelis, S.; Bodin, P.; Hagel, K.; Fletcher, D.

    2010-12-01

    Long-period noise generated by the elastic response of the Earth to atmospheric pressure fluctuations has long been recognized as a limiting factor for seismic investigations. The quality of seismic data recorded by sensitive, near-surface broadband seismometers can be severely corrupted by this effect. During the recent installation of a new broadband site on the Olympic Peninsula in Washington, the Pacific Northwest Seismic Network recorded and investigated elevated daytime noise levels at periods exceeding 30 seconds. Substantial power spectral density variations of the background noise field, 15-20 dB, were observed in the horizontal component seismograms. The pattern of the long-period noise exhibited striking correlations with local fluctuations of the air temperature and wind speed as measured nearby the seismic station by the National Weather Service Forecast Office, Seattle, Washington, and the National Oceanic and Atmospheric Administration. Several past studies have demonstrated that local wind systems may lead to variations of the atmospheric pressure field that deform the ground and perturb seismograms. The rotational component of this motion is detected by horizontal-component seismometers because at periods longer than the sensor’s low corner frequency the sensor is acting essentially as a tiltmeter. We obtained a transfer function that describes the response of the broadband seismometer to a tilt step change and estimated the amplitude of tilt noise to be on the order of 10-9 - 10-8 radians. Within the seismic pass-band of the sensor, it is not possible to remove the tilt signal from the observed seismograms because the details of the tilting depend on the pressure field variations, the compliance of the near surface to pressure variations, and the design and construction of the seismometer vault itself. At longer periods, using the seismic data to recover tilts of tectonic origin is made challenging because of the needed instrument correction

  9. Field-Free Atmospheric Pressure Photoionization - Liquid Chromatography - Mass Spectrometry for the Analysis of Steroids within Complex Biological Matrices.

    Science.gov (United States)

    McCulloch, Ross David; Robb, Damon B

    2017-03-06

    A comparison study is presented in which the relative performance of a new orthogonal geometry field-free atmospheric pressure photoionization (FF-APPI) source was evaluated against both electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) for the analysis of a small panel of clinically relevant steroids, spiked within various complex biological matrices. Critical performance factors like sensitivity and susceptibility to matrix effects were assessed using a simple, isocratic, high throughput LC-MS workflow. FF-APPI was found to provide the best performance in terms of both sensitivity and detection limit for all of the steroids included in the survey. Order-of-magnitude sensitivity advantages were realized for some low polarity analytes including both estradiol and estrone. A robust linear regression, post extraction addition method was used to evaluate the relative impact of matrix effects upon each ionization method using protein precipitated human serum, plasma and Surine (simulated urine) as standard clinical matrices. Under conditions optimized for sensitivity, both the field-free APPI and APCI sources were found to provide similarly high resistance to matrix suppression effects, while ESI performance was impacted the most dramatically. For the prototype FF-APPI source, a strong relationship was established between optimizable source parameters and the degree of ion suppression observed. Through careful optimization of vaporization temperature and nebulizer gas flow rates it was possible to significantly reduce or even eliminate the impact of matrix effects, even for high throughput LC-MS methods.

  10. Improved background rejection in neutrinoless double beta decay experiments using a magnetic field in a high pressure xenon TPC

    CERN Document Server

    Renner, J; Hernando, J A; Imzaylov, A; Monrabal, F; Muñoz, J; Nygren, D; Gomez-Cadenas, J J

    2015-01-01

    We demonstrate that the application of an external magnetic field could lead to an improved background rejection in neutrinoless double-beta (0nbb) decay experiments using a high pressure xenon (HPXe) TPC. HPXe chambers are capable of imaging electron tracks, a feature that enhances the separation between signal events (the two electrons emitted in the 0nbb decay of 136Xe) and background events, arising chiefly from single electrons of kinetic energy compatible with the end-point of the 0nbb decay (Qbb ). Applying an external magnetic field of sufficiently high intensity (in the range of 0.5-1 Tesla for operating pressures in the range of 5-15 atmospheres) causes the electrons to produce helical tracks. Assuming the tracks can be properly reconstructed, the sign (direction) of curvature can be determined at several points along these tracks, and such information can be used to separate signal (0nbb) events containing two electrons producing a track with two different directions of curvature from background (s...

  11. Polymorphism of iron at high pressure: A 3D phase-field model for displacive transitions with finite elastoplastic deformations

    Science.gov (United States)

    Vattré, A.; Denoual, C.

    2016-07-01

    A thermodynamically consistent framework for combining nonlinear elastoplasticity and multivariant phase-field theory is formulated at large strains. In accordance with the Clausius-Duhem inequality, the Helmholtz free energy and time-dependent constitutive relations give rise to displacive driving forces for pressure-induced martensitic phase transitions in materials. Inelastic forces are obtained by using a representation of the energy landscape that involves the concept of reaction pathways with respect to the point group symmetry operations of crystal lattices. On the other hand, additional elastic forces are derived for the most general case of large strains and rotations, as well as nonlinear, anisotropic, and different elastic pressure-dependent properties of phases. The phase-field formalism coupled with finite elastoplastic deformations is implemented into a three-dimensional Lagrangian finite element approach and is applied to analyze the iron body-centered cubic (α-Fe) into hexagonal close-packed (ɛ-Fe) phase transitions under high hydrostatic compression. The simulations exhibit the major role played by the plastic deformation in the morphological and microstructure evolution processes. Due to the strong long-range elastic interactions between variants without plasticity, a forward α → ɛ transition is energetically unfavorable and remains incomplete. However, plastic dissipation releases considerably the stored strain energy, leading to the α ↔ ɛ ↔α‧ (forward and reverse) polymorphic phase transformations with an unexpected selection of variants.

  12. Nutritional approaches and health-related properties of plant foods processed by high pressure and pulsed electric fields.

    Science.gov (United States)

    Sánchez-Moreno, Concepción; de Ancos, Begoña; Plaza, Lucía; Elez-Martínez, Pedro; Cano, M Pilar

    2009-06-01

    Consumers are more and more concerned about the nutritional and health-related characteristics of fruits and vegetables, as well as the safety of the food they eat. The processing of foods is becoming more sophisticated and diverse in response to the growing demand for quality foods. Consumers today expect food products to provide fresh-like appearance, convenience, variety, appropriate shelf-life and caloric content, reasonable cost, environmental soundness, high nutritional and functional quality. Nonthermal processing of fruit and vegetable has been revealed as a useful tool to extend their shelf-life and quality as well as to preserve their nutritional and functional characteristics. In the last ten years, there has been an increasing interest in nonthermal technologies as high pressure processing (HPP) and pulsed electric fields (PEF) to preserve fruit and vegetable products without the quality and nutritional damage caused by heat treatments. This review will contribute to inform many of the studies conducted to obtain a better understanding on the effects of some of these nonthermal processing technologies (high hydrostatic pressure and pulsed electric fields) applied to vegetable foods on their nutritional value and bioactive compounds related to health, including the results on micronutrient bioavailability studies and oxidative stress and inflammation biomarkers. These studies could contribute to select the most appropriate processing parameters to obtain safe, high-quality, nutritional, and functional vegetable food.

  13. Effects of pressure and magnetic field on superconductivity in ZrTe3: local pair-induced superconductivity

    Science.gov (United States)

    Tsuchiya, S.; Matsubayashi, K.; Yamaya, K.; Takayanagi, S.; Tanda, S.; Uwatoko, Y.

    2017-06-01

    In this work, the origin of the highly anisotropic superconducting transition in ZrTe3, where the resistance along the a axis, R a , is reduced at 4 K but those along the b axis, R b , and {c}\\prime axis, R c‧, are reduced at 2 K, was explored with the application of a magnetic field and pressure by the electrical resistance measurements. We found that the behavior of the upper critical field and its anisotropy as well as the pressure dependence determined by the R a measurements are quite similar to those of R b . Moreover, the excess conductivity for R b indicates anomalous behavior. These results support an unconventional origin for the anisotropic transition rather than conventional superconducting fluctuation. The reduction in R a is due to filamentary superconductivity (SC) induced by locally bound electron pairs (local pairs), which correspond to bi-polarons, and the transition of R b corresponds to the emergence of bulk SC originating from the Cooper pairs triggered by the transfer of the local pairs.

  14. A diffusive atmospheric pressure glow discharge in a coaxial pin-to-ring gap with a transverse magnetic field

    Directory of Open Access Journals (Sweden)

    YongSheng Wang

    2017-09-01

    Full Text Available Atmospheric pressure glow discharge (APGD has been widely used in the industrial field. The industrial applications are based on achieving stable and diffusive APGD in a relatively large space. The existing sources only achieved stable and diffusive APGD between a short inter-electrode distance within 5 millimeters. In this paper, the effect of a transverse stationary magnetic field on the diffusion of filamentary APGD was studied in a pin-to-ring coaxial gap. The APGD was driven by a high-voltage resonant power supply, and the stationary magnetic field was supplied by a permanent magnet. The stable and diffusive APGD was achieved in the circular area, which diameter was 20 millimeters. The experimental results revealed that more collision ionization occurred and the plasma was distributed diffusively in the discharge gap by applying the external transverse magnetic field. Besides, it is likely to obtain more stable and diffusive APGD in the coaxial pin-to-ring discharge gap when adjusting the input voltage, transverse magnetic flux density and resonant frequency of the power supply.

  15. Subsurface monitoring of reservoir pressure, temperature, relative humidity, and water content at the CAES Field Experiment, Pittsfield, Illinois: system design

    Energy Technology Data Exchange (ETDEWEB)

    Hostetler, D.D.; Childs, S.W.; Phillips, S.J.

    1983-03-01

    This subsurface-instrumentation design has been developed for the first Compressed Air Energy Storage (CAES) field experiment to be performed in porous media. Energy storage will be accomplished by alternating the injection and withdrawal of compressed air in a confined sandstone aquifer near Pittsfield, Illinois. The overall experiment objective is to characterize the reservoir's geochemical and thermohydraulic response to imposed CAES conditions. Specific experiment objectives require monitoring: air-bubble development; thermal development; cyclic pressure response; reservoir dehydration; and water coning. Supporting these objectives, four parameters will be continuously monitored at depth in the reservoir. They are: temperature; pressure; pore-air relative humidity; and pore-water content. Reservoir temperatures and pressures will range to maximum values approaching 200/sup 0/C and 300 psi, respectively. Both pore-air relative humidity and pore-water content will range from approx. 0 to 100%. This report discusses: instrumentation design; sensor and sensor system calibration; field installation and testing; and instrument-system operation. No comprehensive off-the-shelf instrument package exists to adequately monitor CAES reservoir parameters at depth. The best available sensors were selected and adapted for use under expected ranges of reservoir conditions. The instrumentation design criteria required: suitable sensor accuracy; continuous monitoring capability; redundancy; maximum sensor integrity; contingency planning; and minimum cost-information ratio. Three wells will be instrumented: the injection/withdrawal (I/W) well and the two instrument wells. Sensors will be deployed by wireline suspension in both open and backfilled (with sand) wellbores. The sensors deployed in the I/W well will be retrievable; the instrument-well sensors will not.

  16. Surface Breakdown of Printed Circuit Board under Magnetic Field with Reduced Pressure

    Institute of Scientific and Technical Information of China (English)

    杜伯学; 朱晓辉; 高宇; 卢欣

    2010-01-01

    Epoxy resin laminate onto which a pair of copper foil was printed was employed as test samples.The samples were placed in an artificial atmospheric chamber, which was vacuumed by a rotary pump from 100 kPa to 5 kPa.The magnetic field was produced by permanent magnets that were assembled to make E×B drift away from, into and parallel to the sample surface, respectively.Magnetic flux density was adjusted at 120 mT, 180 mT and 240 mT respectively.By applying a negative bias voltage between the electrodes, the ...

  17. Mean-field potential calculations of high-pressure equation of state for BeO

    Institute of Scientific and Technical Information of China (English)

    Zhang Qi-Li; Zhang Ping; Song Hai-Feng; Liu Hai-Feng

    2008-01-01

    A systematic study of the Hugoniot equation of state, phase transition, and the other thermodynamic properties including the Hugoniot temperature, the electronic and ionic heat capacities, and the Griineisen parameter for shockcompressed BeO, has been carried out by calculating the total free energy. The method of calculations combines first-principles treatment for 0 K and finite-T electronic contribution and the mean-field-potential approach for the vibrational contribution of the lattice ion to the total energy. Our calculated Hugoniot is in good agreement with the experimental data.

  18. Photoluminescence energy transitions in GaAs-Ga{sub 1-x}Al{sub x}As double quantum wells: Electric and magnetic fields and hydrostatic pressure effects

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, S.Y. [Grupo de Educacion en Ciencias Experimentales y Matematicas-GECEM, Facultad de Educacion, Universidad de Antioquia, AA 1226 Medellin (Colombia); Mora-Ramos, M.E. [Facultad de Ciencias, Universidad Autonoma del Estado de Morelos, Av. Universidad 1001, CP 62209, Cuernavaca, Morelos (Mexico); Duque, C.A., E-mail: cduque@fisica.udea.edu.c [Instituto de Fisica, Universidad de Antioquia, AA 1226 Medellin (Colombia)

    2009-12-15

    The photoluminescence energy transitions in GaAs-Ga{sub 1-x}Al{sub x}As coupled double quantum wells are presented by considering the simultaneous effects of applied electric and magnetic fields and hydrostatic pressure. Calculations have been made in the framework of the effective mass and parabolic band approximations and using a variational procedure. The electric field is taken to be oriented along the growth direction of the heterostructure whereas for the magnetic field both in-plane and in-growth directions have been considered. The results show that the hydrostatic pressure and the applied electric field are two useful tools to tune the direct and indirect exciton transitions in such heterostructures. Our results are in good agreement with previous experimental findings in double quantum wells under applied electric field and hydrostatic pressure.

  19. Condensed argon isentropic compression with ultrahigh magnetic field pressure: Experimental design. Post-shot report

    Energy Technology Data Exchange (ETDEWEB)

    Bykov, A.I.; Boriskov, G.V.; Dolotenko, M.I. [All-Russian Research Inst. of Experimental Physics, Sarov (Russian Federation)] [and others

    1996-12-31

    This report continues the series of work devoted to experimental study of a high-dense condensed argon state. Remember that according to work of Kwon et. al., hexagonal close-packed structure is profitable in terms of energy rather than face-centered argon structure (stable with zero pressure). What is most interesting and intriguing here is the issue of possible argon metallization, when it is compressed up to the densities more than 9.17 g/cm{sup 3}. In the experiment of 1995 (the arrangement and data are described in a cited reference) the authors recorded appearance of conductivity in argon, which is non-conductive in the initial state, when it is compressed more than a factor of four. The peak value of argon specific conductivity recorded in this experiment did not exceed 10 (Ohm x cm){sup {minus}1}. This value of conductivity is characteristic of semiconductors, but not metals, which have 10{sup 4} (Ohm x cm){sup {minus}1}. At this stage of the work the main attention is paid to recording of argon conductive state and studying the possibilities of multiframed radiography of the sample in the compressed state.

  20. Spectroscopic study of partially-ordered semiconductor heterojunction under high pressure and high magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Yu, P.Y.; Martinez, G.; Zeman, J.; Uchida, K.

    2000-12-31

    Photoluminescence upconversion (PLU) is a phenomenon in which a sample emits photons with energy higher than that of the excitation photon. This effect has been observed in many materials including rare earth ions doped in insulating hosts and semiconductor heterostructures without using high power lasers as the excitation source. Recently, this effect has been observed also in partially CuPt-ordered GaInP{sub 2} epilayers grown on GaAs substrates. As a spectroscopic technique photoluminescence upconversion is particularly well suited for studying band alignment at heterojunction interface. The value of band-offset has been determined with meV precision using magneto-photoluminescence. Using the fact that the pressure coefficient of electrons in GaAs is higher than those in GaInP{sub 2} they have been able to manipulate the band-offset at the GaInP/GaAs interface. By converting the band-offset from Type I to Type II they were able to demonstrate that the efficiency of the upconversion process is greatly enhanced by a Type II band-offset.

  1. Artificial reproduction of magnetic fields produced by a natural geomagnetic storm increases systolic blood pressure in rats

    Science.gov (United States)

    Martínez-Bretón, J. L.; Mendoza, B.; Miranda-Anaya, M.; Durán, P.; Flores-Chávez, P. L.

    2016-04-01

    The incidence of geomagnetic storms may be associated with changes in circulatory physiology. The way in which the natural variations of the geomagnetic field due to solar activity affects the blood pressure are poorly understood and require further study in controlled experimental designs in animal models. In the present study, we tested whether the systolic arterial pressure (AP) in adult rats is affected by simulated magnetic fields resembling the natural changes of a geomagnetic storm. We exposed adult rats to a linear magnetic profile that simulates the average changes associated to some well-known geomagnetic storm phases: the sudden commencement and principal phase. Magnetic stimulus was provided by a coil inductor and regulated by a microcontroller. The experiments were conducted in the electromagnetically isolated environment of a semi-anechoic chamber. After exposure, AP was determined with a non-invasive method through the pulse on the rat's tail. Animals were used as their own control. Our results indicate that there was no statistically significant effect in AP when the artificial profile was applied, neither in the sudden commencement nor in the principal phases. However, during the experimental period, a natural geomagnetic storm occurred, and we did observe statistically significant AP increase during the sudden commencement phase. Furthermore, when this storm phase was artificially replicated with a non-linear profile, we noticed a 7 to 9 % increase of the rats' AP in relation to a reference value. We suggested that the changes in the geomagnetic field associated with a geomagnetic storm in its first day could produce a measurable and reproducible physiological response in AP.

  2. Artificial reproduction of magnetic fields produced by a natural geomagnetic storm increases systolic blood pressure in rats

    Science.gov (United States)

    Martínez-Bretón, J. L.; Mendoza, B.; Miranda-Anaya, M.; Durán, P.; Flores-Chávez, P. L.

    2016-11-01

    The incidence of geomagnetic storms may be associated with changes in circulatory physiology. The way in which the natural variations of the geomagnetic field due to solar activity affects the blood pressure are poorly understood and require further study in controlled experimental designs in animal models. In the present study, we tested whether the systolic arterial pressure (AP) in adult rats is affected by simulated magnetic fields resembling the natural changes of a geomagnetic storm. We exposed adult rats to a linear magnetic profile that simulates the average changes associated to some well-known geomagnetic storm phases: the sudden commencement and principal phase. Magnetic stimulus was provided by a coil inductor and regulated by a microcontroller. The experiments were conducted in the electromagnetically isolated environment of a semi-anechoic chamber. After exposure, AP was determined with a non-invasive method through the pulse on the rat's tail. Animals were used as their own control. Our results indicate that there was no statistically significant effect in AP when the artificial profile was applied, neither in the sudden commencement nor in the principal phases. However, during the experimental period, a natural geomagnetic storm occurred, and we did observe statistically significant AP increase during the sudden commencement phase. Furthermore, when this storm phase was artificially replicated with a non-linear profile, we noticed a 7 to 9 % increase of the rats' AP in relation to a reference value. We suggested that the changes in the geomagnetic field associated with a geomagnetic storm in its first day could produce a measurable and reproducible physiological response in AP.

  3. High-pressure study of the basal-plane anisotropy of the upper critical field of the topological superconductor SrxBi2Se3

    Science.gov (United States)

    Nikitin, A. M.; Pan, Y.; Huang, Y. K.; Naka, T.; de Visser, A.

    2016-10-01

    We report a high-pressure transport study of the upper-critical field Bc 2(T ) of the topological superconductor Sr0.15Bi2Se3 (Tc=3.0 K). Bc 2(T ) was measured for magnetic fields directed along two orthogonal directions, a and a*, in the trigonal basal plane. While superconductivity is rapidly suppressed at the critical pressure pc˜3.5 GPa, the pronounced two-fold basal-plane anisotropy Bc2 a/Bc2 a*=3.2 at T =0.3 K, recently reported at ambient pressure [Pan et al., Sci. Rep. 6, 28632 (2016), 10.1038/srep28632], is reinforced and attains a value of ˜5 at the highest pressure (2.2 GPa). The data reveal that the unconventional superconducting state with broken rotational symmetry is robust under pressure.

  4. High pressure annular two-phase flow in a narrow duct. Part 1: Local measurements in the droplet field, and Part 2: Three-field modeling

    Energy Technology Data Exchange (ETDEWEB)

    Trabold, T.A.; Kumar, R. [Lockheed Martin Corp., Schenectady, NY (United States)

    1999-07-01

    In Part 1, detailed measurements were made in a high pressure, adiabatic (boiled at the inlet) annular flow in a narrow, high aspect ratio duct using a gamma densitometer, hot-film anemometer and high-speed video photography. Measurements of void fraction, droplet frequency, velocity, drop size, and interfacial area concentration have been made to support the three field computational capability. An important aspect of this testing is the use of a modeling fluid (R-134a) in a vertical duct which permits visual access in annular flow. This modeling fluid accurately simulates the low liquid-to-vapor density ratio of steam-water flows at high pressures. These measurements have been taken in a narrow duct of hydraulic diameter 4.85 mm, and a cross-section aspect ratio of 22.5. However, the flow displays profiles of various shapes not only in the narrow dimension, but also in the width dimension. In particular, the shape of the droplet profiles depends on the entrained droplet flux from the edges in the vapor core. The average diameter from these profiles compare well with the models developed in the literature. Interfacial area concentration for these low density ratio flows is higher than the highest concentration reported for air-water flows. Video records show that along with the bow-shaped waves, three-dimensional {lambda}-shaped waves appear in annular flows for high flow rates. Part 2 outlines the development of a three-field modeling approach in annular flow and the predictive capability of an analysis code. Models have been developed here or adapted from the literature for the thin film near the wall as well as the droplets in the vapor core, and have been locally applied in a fully developed, two-phase adiabatic boiling annular flow in a duct heated at the inlet at high pressure. Numerical results have been obtained using these models that are required for the closure of the continuity and momentum equations. The two-dimensional predictions are compared with

  5. Field-Emission Study of Multi-Walled Carbon Nanotubes Grown On Si Substrate by Low Pressure Chemical Vapor Deposition

    Directory of Open Access Journals (Sweden)

    J. Ali

    2011-01-01

    Full Text Available CNTs are synthesized by Low Pressure Chemical Vapor Deposition (LPCVD method at 600 °C. The Si substrate is coated with Fe, used as a catalyst, by RF- sputtering. The thickness of the catalyst film is measured to be approximately 15 nm. Three precursor gases Acetylene (C2H2, Ammonia (NH3 and Hydrogen (H2 with flow rates 15 sccm, 100 sccm and 100 sccm respectively are allowed to flow through the tube reactor for 20 minutes. The as grown CNTs sample was characterized by Scanning Electron Microscope (SEM. SEM images show that the diameter of as grown CNTs is in the range of 20-50 nm. Field emission properties of as grown sample have also been studied. The CNTs film shows good field emission with turn on field Eα = 2.10 V/μm at the current density of 4.59 mA/cm2 with enhancement factor β = 1.37 × 102.

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

    Science.gov (United States)

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

    2017-01-01

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

  7. Ground surface temperature reconstructions: Using in situ estimates for thermal conductivity acquired with a fiber-optic distributed thermal perturbation sensor

    Energy Technology Data Exchange (ETDEWEB)

    Freifeld, B.M.; Finsterle, S.; Onstott, T.C.; Toole, P.; Pratt, L.M.

    2008-10-10

    We have developed a borehole methodology to estimate formation thermal conductivity in situ with a spatial resolution of one meter. In parallel with a fiber-optic distributed temperature sensor (DTS), a resistance heater is deployed to create a controlled thermal perturbation. The transient thermal data is inverted to estimate the formation's thermal conductivity. We refer to this instrumentation as a Distributed Thermal Perturbation Sensor (DTPS), given the distributed nature of the DTS measurement technology. The DTPS was deployed in permafrost at the High Lake Project Site (67 degrees 22 minutes N, 110 degrees 50 minutes W), Nunavut, Canada. Based on DTPS data, a thermal conductivity profile was estimated along the length of a wellbore. Using the thermal conductivity profile, the baseline geothermal profile was then inverted to estimate a ground surface temperature history (GSTH) for the High Lake region. The GSTH exhibits a 100-year long warming trend, with a present-day ground surface temperature increase of 3.0 {+-} 0.8 C over the long-term average.

  8. Gap junctional regulation of pressure, fluid force, and electrical fields in the epigenetics of cardiac morphogenesis and remodeling.

    Science.gov (United States)

    Seki, Akiko; Nishii, Kiyomasa; Hagiwara, Nobuhisa

    2015-05-15

    Epigenetic factors of pressure load, fluid force, and electrical fields that occur during cardiac contraction affect cardiac development, morphology, function, and pathogenesis. These factors are orchestrated by intercellular communication mediated by gap junctions, which synchronize action potentials and second messengers. Misregulation of the gap junction protein connexin (Cx) alters cardiogenesis, and can be a pathogenic factor causing cardiac conduction disturbance, fatal arrhythmia, and cardiac remodeling in disease states such as hypertension and ischemia. Changes in Cx expression can occur even when the DNA sequence of the Cx gene itself is unaltered. Posttranslational modifications might reduce arrhythmogenic substrates, improve cardiac function, and promote remodeling in a diseased heart. In this review, we discuss the epigenetic features of gap junctions that regulate cardiac morphology and remodeling. We further discuss potential clinical applications of current knowledge of the structure and function of gap junctions. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. NUMERICAL ANALYSIS OF THE 3-D FLOW FIELD OF PRESSURE ATOMIZERS WITH V-SHAPED CUT AT ORIFICE

    Institute of Scientific and Technical Information of China (English)

    ZHOU Hua

    2011-01-01

    Axisymmetric liquid jets have been studied extensively for more than one century, while non-axisymmetric jets are also very common in engineering applications but attract less concern. Based on Eulerian fluid-fluid model in Fluent software, this article analysizes the 3-D flow fields of pressure atomizers with V-shaped cut at orifice, which will result in a non-axisymmetric liquid jet.Flow rate analysis and jet structure analysis are carried out, the results show that the flow rate can be formulated by adding a correction coefficient to the formula of inviscid axisymmetric jets in atomization regime, when the Weber number is low enough to make the flow fall out of atomization regime, and the jet structure together with the flow rate formula will change. Analysis shows that the evolution of the spray and therefore the structure of the liquid jet are affected much by relative velocity and the local volume fraction of liquid phase.

  10. Consumer perception of the use of high-pressure processing and pulsed electric field technologies in food production

    DEFF Research Database (Denmark)

    Nielsen, Henriette Boel; Sonne, Anne-Mette; Grunert, Klaus G.

    2009-01-01

    . Participants were introduced to the HPP and PEF technologies and then to the effect of the two new technologies on two specific product categories: juice and baby food. The transcribed data was content analysed and the coded data was transformed into diagrams using UCINET 5 and NETDRAW. The results show......The success of new food processing technologies is highly dependent on consumers' acceptance. The purpose of this paper is to study consumers' perceptions of two new processing technologies and food products produced by means of these novel technologies. To accomplish this, a qualitative study...... on consumer attitudes towards high-pressure processing (HPP) and pulsed electric field (PEF) processing of food was carried out. In all 97 adults between 20 and 71 years of age participated in 12 focus groups conducted in Slovenia, Hungary, Serbia, Slovakia, Norway and Denmark using a common guideline...

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

    Science.gov (United States)

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

    2017-03-01

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

  12. Field test of two high-pressure direct-contact downhole steam generators. Volume II. Oxygen/diesel system

    Energy Technology Data Exchange (ETDEWEB)

    Moreno, J.B.

    1983-07-01

    A field test of an oxygen/diesel fuel, direct contact steam generator has been completed. The field test, which was a part of Project DEEP STEAM and was sponsored by the US Department of Energy, involved the thermal stimulation of a well pattern in the Tar Zone of the Wilmington Oil Field. The activity was carried out in cooperation with the City of Long Beach and the Long Beach Oil Development Company. The steam generator was operated at ground level, with the steam and combustion products delivered to the reservoir through 2022 feet of calcium-silicate insulated tubing. The objectives of the test included demonstrations of safety, operational ease, reliability and lifetime; investigations of reservoir response, environmental impact, and economics; and comparison of those points with a second generator that used air rather than oxygen. The test was extensively instrumented to provide the required data. Excluding interruptions not attributable to the oxygen/diesel system, steam was injected 78% of the time. System lifetime was limited by the combustor, which required some parts replacement every 2 to 3 weeks. For the conditions of this particular test, the use of trucked-in LOX resulted in liess expense than did the production of the equivalent amount of high pressure air using on site compressors. No statistically significant production change in the eight-acre oxygen system well pattern occurred during the test, nor were any adverse effects on the reservoir character detected. Gas analyses during the field test showed very low levels of SOX (less than or equal to 1 ppM) in the generator gaseous effluent. The SOX and NOX data did not permit any conclusion to be drawn regarding reservoir scrubbing. Appreciable levels of CO (less than or equal to 5%) were measured at the generator, and in this case produced-gas analyses showed evidence of significant gas scrubbing. 64 figures, 10 tables.

  13. The nonlinear optical rectification and second harmonic generation in asymmetrical Gaussian potential quantum well: Effects of hydrostatic pressure, temperature and magnetic field

    Science.gov (United States)

    Liu, Xin; Zou, LiLi; Liu, Chenglin; Zhang, Zhi-Hai; Yuan, Jian-Hui

    2016-03-01

    In the present work, the effects of hydrostatic pressure, temperature, and magnetic field on the nonlinear optical rectification (OR) and second-harmonic generation (SHG) in asymmetrical Gaussian potential quantum well (QW) have been investigated theoretically. Here, the expressions for the optical properties are calculated by the compact-density-matrix approach and iterative method. Simultaneously, the energy eigenvalues and their corresponding eigenfunctions have been obtained by using the finite difference method. The energy eigenvalues and the shape of the confined potential are modulated by the hydrostatic pressure, temperature, and magnetic field. So the results of a number of numerical experiments indicate that the nonlinear OR and SHG strongly depends on the hydrostatic pressure, temperature, and magnetic field. This gives a new degree of freedom in various device applications based on the intersubband transitions of electrons.

  14. Linear and nonlinear optical absorption coefficients and refractive index changes in modulation-doped quantum wells: Effects of the magnetic field and hydrostatic pressure

    Energy Technology Data Exchange (ETDEWEB)

    Nazari, M.; Karimi, M.J., E-mail: karimi@sutech.ac.ir; Keshavarz, A.

    2013-11-01

    In this study, the linear, the third-order nonlinear and total optical absorption coefficients and refractive index changes of a modulation-doped GaAs/Al{sub x}Ga{sub 1−x}As quantum well are investigated numerically. In the effective-mass approximation, the electronic structure of modulation-doped quantum well is calculated by solving the Schrödinger and Poisson equations self-consistently. Optical properties are obtained using the compact density matrix approach. The effects of structure parameters, the applied magnetic field and the hydrostatic pressure on the optical properties of the modulation-doped quantum well are studied. Results show that the resonant peaks shift toward the higher (lower) energies with the increase in the magnetic field (pressure). The magnitude of the resonant peaks of the optical properties decreases with the increasing magnetic field or pressure.

  15. Origins of and countermeasures for the abnormal pressures in well production of the Ojarly gas field in the Right Bank of the Amu-Darya River, Turkmenistan

    Directory of Open Access Journals (Sweden)

    Peijun Zhang

    2017-01-01

    Full Text Available The Ojarly gas field, the major supplier of the Project Phase Ⅱ of the Right Bank of the Amu Darya River, is just small but valuable like a golden bean, although it has good reservoir properties and a high gas production capacity, the occurrence of continuous sharp decline of pressure in the well production shows a great difference from the previous well test program. In view of this, an integrated analysis method was established for the whole gas well production process to discover the three main reasons causing the abnormal well pressure. First, the formation energy and pressure dropped so fast that the wellhead pressure also fell over the period. Second, there was abnormal fluids pressure drop in the wellbore tube and throttling effect might occur in the production tube, so the pressure drop became abnormally increased. Third, due to the abnormally-increasing gas-yield pressure drop and unusually-decreasing gas productivity, the wellhead oil pressure dropped significantly. Also, through dynamic monitoring and in-depth analysis, it is also considered that due to the high density of drilling fluids and well-developed pores and caverns in the reservoirs, more and more barites separated from the fluids would be settled down covering the pay zones, so both the gas-generating capacity and production pressure significantly decreased. On this basis, some technical countermeasures were taken such as re-stimulation of reservoirs, removal of gas-producing channels, increase of seepage capacity, etc. In addition, by use of sand-flushing and acidizing, both the comprehensive skin factor and the production pressure drop were reduced to improve the well gas production capacity and maintain high productivity effectively. This study provides a technical support for long-term sustainable development and production of this gas field.

  16. Underground Coal Mine Methane Displacement by Injecting Low-pressure Gas into the Meta-anthracite Seam: Laboratory and Field Tests

    Directory of Open Access Journals (Sweden)

    Yu Hong

    2014-09-01

    Full Text Available Because of the strong adsorption capacity of meta-anthracite, the gas content of a meta-anthracite seam can be as high as 10 m3/t, with a gas pressure lower than 0.74 MPa; this results in low efficiency of gas extraction in underground mines. To enhance low-pressure methane extraction efficiency in meta-anthracite seams, a new approach – methane displacement by gas injection – has been developed, investigated in the laboratory, and then applied in the field in the Fuyanshan coal mine. Laboratory results show that when the gas content of the coal seam is high, methane displacement by nitrogen injection is difficult. The volume of methane displaced is directly related to the pressure difference between the coal seam gas pressure and the injection gas pressure. If the total gas pressure is greater than 0.5 MPa after nitrogen injection, then the methane displacement efficiency will be greatly enhanced. It is also confirmed that the displacement efficiency can be improved by injecting inert gas to change the partial pressure of the methane. Field test data show quite good methane displacement efficiency.

  17. Continuous Pressure and Temperature Monitoring in Lower Arbuckle Saline Aquifer in Wellington Field, Sumner County, Kansas - Response to the M5.8 Pawnee Earthquake

    Science.gov (United States)

    Watney, W. L.; Bidgoli, T. S.; Victorine, J.; Simpson, P.; Holubnyak, Y.; Nolte, K.; Tsoflias, G. P.; Wreath, D.; Birdie, T. R.

    2016-12-01

    Since April 2016 a downhole P/T gauge has been continuously recording high-resolution data (1 /sec, 0.7 kP and 0.01 ºC accuracy) in the lower Arbuckle saline aquifer at a depth of 1524 m in the Berexco Wellington KGS #1-28 well. The cased well was perforated and tested in August 2011 and has remained idle since. The wellsite located in south-central Kansas has experienced the introduction of numerous, low magnitude earthquakes since early 2015. The downhole pressure measured at the start of continuous monitoring in April 2016 was 216 kP above pressures measured five years before in August 2011. Pressure has risen at a rate of up to 4.1 kP /mo until 9-1-16, two-days prior to the Pawnee earthquake, after which time, long-term pressure has remained essentially level (mid October 2017). In addition, short-term, multiple, hours-long, asymmetric pressure spikes of up to 345 kP accompanied by temperature falls of 0.3 ºC have been observed. The M5.8 Pawnee earthquake was detected by pressure oscillations (1.4 to 5.5 kP and 0.1 sec freq) coinciding closely with the larger amplitude portion of the earthquake's CODA. Oscillations are attributed local aquifer and wellbore effects from the wave train of the passing earthquake. The validation of a regional pressure field forecasted by simulation of brine disposal by Bidgoli et al. (2016) suggests hydrologic continuity of the regional Arbuckle aquifer and a possible explanation for the observed expansion of the seismicity linked to the pressure field. Short term spikes of pressure increases and temperature falls suggest cooler brine entering casing perforations that accompany the pressure increase. These short term anomalies are attributed to changes in disposal rates and casing pressure of wells in the local vicinity. The leveling off of pressure that occurred 2-days before the Pawnee earthquake may be just a coincidence, but could potentially have occurred either from moving brine from the Arbuckle into another formation or

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

    Science.gov (United States)

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

    2016-12-01

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

  19. Consumer perception of the use of high-pressure processing and pulsed electric field technologies in food production.

    Science.gov (United States)

    Nielsen, Henriette Boel; Sonne, Anne-Mette; Grunert, Klaus G; Banati, Diana; Pollák-Tóth, Annamária; Lakner, Zoltán; Olsen, Nina Veflen; Zontar, Tanja Pajk; Peterman, Marjana

    2009-02-01

    The success of new food processing technologies is highly dependent on consumers' acceptance. The purpose of this paper is to study consumers' perceptions of two new processing technologies and food products produced by means of these novel technologies. To accomplish this, a qualitative study on consumer attitudes towards high-pressure processing (HPP) and pulsed electric field (PEF) processing of food was carried out. In all 97 adults between 20 and 71 years of age participated in 12 focus groups conducted in Slovenia, Hungary, Serbia, Slovakia, Norway and Denmark using a common guideline. Participants were introduced to the HPP and PEF technologies and then to the effect of the two new technologies on two specific product categories: juice and baby food. The transcribed data was content analysed and the coded data was transformed into diagrams using UCINET 5 and NETDRAW. The results show that consumers perceived the main advantages of HPP and PEF products to be the products' naturalness, improved taste and their high nutritional value, whereas the main disadvantage was the lack of information about the PEF and HPP products. The results of the participants' evaluation of the PEF and HPP processes showed that environmental friendliness and the more natural products were seen as the main advantages, while they were concerned about body and health, the higher price of the products, the lack of information about the technologies and a general scepticism. The study also shows that North European participants were a bit more sceptical towards PEF and HPP products than the East European participants.

  20. Field emission from α-Fe2O3 nanoflakes: Effect of vacuum pressure, gas adsorption and in-situ thermal treatment

    Science.gov (United States)

    Wu, J. Q.; Deng, S. Z.; Xu, N. S.; Chen, Jun

    2014-02-01

    The effects of vacuum pressure and gas adsorption on field emission current of α-Fe2O3 nanoflakes were studied. It was found that field emission current of α-Fe2O3 nanoflakes decreased with increasing pressure. The field emission current decreased when N2 or O2 was introduced into chamber, while no obvious change was observed for H2 gas. An in-situ thermal treatment was carried out to eradicate the effect of absorbed gas. After the in-situ thermal treatment, the field emission current density was largely enhanced from 60 to 500 μA/cm2 under applied electrical field of 10 MV/m and the turn on field (Eturn-on) decreased from 7.6 to 5.2 MV/m. The lowered turn-on field was attributed to the decrease of surface work function induced by surface gas desorption and reduction of α-Fe2O3 nanoflakes. Moreover, the improvement of field emission performance can be retained in high vacuum condition, which indicates the in-situ thermal treatment is an efficient method to improve field emission properties of α-Fe2O3 nanoflakes.

  1. Study of the electric field and wall voltage in a high pressure ac-PDP cell by laser induced fluorescence spectroscopy

    Institute of Scientific and Technical Information of China (English)

    Zhou Yan; K. W. Whang; J. H. Yang; D. C. Jeong; C.H.Ha; Y.W. Choi

    2004-01-01

    The electric field in a surface discharge type ac-PDP cell with He or He/Xe(0.1%) mixture has been measured over a wide range of pressure (5 50kP1 using laser induced fluorescence detection. The wall voltage was estimated from the measured electric field. The Stark manifolds of triplet atomic helium Rydberg state (2s3S) with principal quantum numbers (n=8 and 9) have been used to measure the electric field, as the lifetime of 2s3S is longer than the single atomic helium Rydberg state (2s1S) in high pressure discharge. Comparison of the Stark manifolds between the n=9 and n=8shows that the measurement accuracy of electric field can be increased by 10%. The maximum electric field strength during discharge and the wall voltage at the end of pulse decreases with the increase of pressure. The comparison of He and He/Xe(0.1%) discharge at 13kPa showed that He/Xe gas mixture discharge can accumulate more wall charge on MgO surface and the electric field was somewhat higher than those of pure helium discharge during pulse off period under the same discharge conditions.

  2. Temperature Fields of Al{sub 2}O{sub 3}/MgF{sub 2} HR Coatings Prepared at Different Working Pressure

    Energy Technology Data Exchange (ETDEWEB)

    Zhan Meiqiong; Wu Zhonglin, E-mail: hbzmq@126.com [Shanghai second polytechnic university, No.2360 Jinhai Road, Shanghai (China)

    2011-02-01

    A series of samples were deposited by electron beam evaporation using the same deposition process at different working pressure. Transmittance of the HR coatings was measured by Lambda 900 spectrometer. Laser-induced damage threshold (LIDT) was measured by a 355 nm Nd:YAG laser with a pulse width of 7 ns. The LIDT results range from 2.69 J/cm{sup 2} to 11.03 J/cm{sup 2} with the working pressure changing. It was found that working pressure has important effects on the absorption and LIDT of 355nm Al{sub 2}O{sub 3}/MgF{sub 2} HR coatings. The temperature rise of HR coatings under laser irradiation was calculated by interfaces absorption model based on the theory of temperature fields. The results of temperature fields agree with the results of LIDT.

  3. Effects of an Intense Laser Field and Hydrostatic Pressure on the Intersubband Transitions and Binding Energy of Shallow Donor Impurities in a Quantum Well

    Institute of Scientific and Technical Information of China (English)

    U. Yesilgul; F. Ungan; E. Kasapoglu; H. Sari; I. S(o)kmen

    2011-01-01

    We have calculated the intersubband transitions and the ground-state binding energies of a hydrogenic donor impurity in a quantum well in the presence of a high-frequency laser field and hydrostatic pressure.The calculations are performed within the effective mass approximation,using a variational method. We conclude that the laser field amplitude and the hydrostatic pressure provide an important effect on the electronic and optical properties of the quantum wells.According to the results obtained from the present work,it is deduced that (i) the binding energies of donor impurity decrease as the laser field increase,(ii) the binding energies of donor impurity increase as the hydrostatic pressure increase,(iii) the intersubband absorption coefficients shift toward lower energies as the hydrostatic pressure increases,(iv) the magnitude of absorption coefficients decrease and also shift toward higher energies as the laser field increase.It is hopeful that the obtained results will provide important improvements in device applications.

  4. Reconstruction of Full-Field Wall Pressure Fluctuations on a Flat Plate in the Wake of a Step Cylinder: Applications of Linear Stochastic Estimation (LSE)

    Science.gov (United States)

    Peng, Di; Chen, Yujia; Wang, Shaofei; Liu, Yingzheng; Wang, Weizhe

    2016-11-01

    Previous studies have shown that it is possible to reconstruct the full flow field based on time-resolved measurements at discrete locations using linear stochastic estimation (LSE). The objective of this study is to develop and apply this technique to wall pressure fluctuation measurements in low speed flows. Time-resolved wall pressure fluctuations on a flat plate in the wake of a step cylinder at low speed (V PSP). The microphone arrays are arranged properly to capture the dominant features in the flow field at 10 kHz. The PSP is excited using a continuous UV-LED, and the luminescent signal is recorded by a high-speed camera at 2 kHz. The microphone data at discrete locations are used to reconstruct the full-field wall pressure fluctuations based on LSE. The PSP results serve as basis for improvement of the LSE scheme and also for validation of the reconstructed pressure field. Other data processing techniques including proper orthogonal decomposition (POD) and dynamic mode decomposition (DMD) are also used for analyzing the unsteady flow features. This LSE technique has great potential in real-time flow diagnostics and control.

  5. Comparing equivalent thermal, high pressure and pulsed electric field processes for mild pasteurization of orange juice. Part I: Impact on overall quality attributes

    NARCIS (Netherlands)

    Timmermans, R.A.H.; Mastwijk, H.C.; Knol, J.J.; Quataert, M.C.J.; Vervoort, L.; Plancken, van der I.; Hendrickx, M.E.; Matser, A.M.

    2011-01-01

    Mild heat pasteurization, high pressure processing (HP) and pulsed electric field (PEF) processing of freshly squeezed orange juice were comparatively evaluated examining their impact on microbial load and quality parameters immediately after processing and during two months of storage. Microbial co

  6. Comparing equivalent thermal, high pressure and pulsed electric field processes for mild pasteurization of orange juice: Part II: Impact on specific chemical and biochemical quality parameters

    NARCIS (Netherlands)

    Vervoort, L.; Plancken, van der I.; Grauwet, T.; Timmermans, R.A.H.; Mastwijk, H.C.; Matser, A.M.; Hendrickx, M.E.; Loey, van A.

    2011-01-01

    The impact of thermal, high pressure (HP) and pulsed electric field (PEF) processing for mild pasteurization of orange juice was compared on a fair basis, using processing conditions leading to an equivalent degree of microbial inactivation. Examining the effect on specific chemical and biochemical

  7. Development of automated welding process for field fabrication of thick walled pressure vessels. Fourth quarter technical progress report for period ending September 28, 1980

    Energy Technology Data Exchange (ETDEWEB)

    1980-01-01

    Progress is reported in research aimed at optimizing an automated welding process for the field fabrication of thick-walled pressure vessels and for evaluating the welded joints. Information is included on the welding equipment, mechanical control of the process, joint design, filler wire optimization, in-process nondestructive testing of welds, and repair techniques. (LCL)

  8. Statistical Investigations on Solar Wind Dynamic Pressure Pulses:Basic features and Their Impacts on Geosynchronous Magnetic Fields

    Science.gov (United States)

    Zuo, Pingbing; Feng, Xueshang

    2016-07-01

    Solar wind dynamic pressure pulse (DPP) structures, across which the dynamic pressure abruptly changes over timescales from a few seconds to several minutes, are often observed in the near-Earth space environment. Recently we have developed a novel procedure that is able to rapidly identify the DPPs from the plasma data stream, and simultaneously define the transition region and smartly select the upstream and downstream region for analysis. The plasma data with high time-resolution from 3DP instrument on board the WIND spacecraft are inspected with this automatic DPP-searching code, and a complete list of solar wind DPPs of historic WIND observations are built up. We perform a statistical survey on the properties of DPPs near 1 AU based on this event list. It is found that overwhelming majority of DPPs are associated with the solar wind disturbances including the CME-related flows, the corotating interaction regions, as well as the complex ejecta. The annual variations of the averaged occurrence rate of DPPs are roughly in phase with the solar activities. Although the variabilities of geosynchronous magnetic fields (GMFs) due to the impact of positive DPPs have been well established, there appears no systematic investigations on the response of GMFs to negative DPPs. Here we also study the decompression/compression effects of very strong negative/positive DPPs on GMFs under northward IMFs. In response to the decompression of strong negative DPPs, GMFs on dayside, near the dawn and dusk on nightside are generally depressed. But near the midnight region, the responses of GMF are very diverse, being either positive or negative. For part of events when GOES is located at the midnight sector, GMF is found to abnormally increase as the result of magnetospheric decompression caused by negative DPPs. It is known that on certain conditions magnetic depression of nightside GMFs can be caused by the impact of positive DPPs. Statistically, both the decompression effect of

  9. Field-induced charge-density-wave transitions in the organic metal α-(BEDT-TTF)2KHg(SCN)4 under pressure

    Science.gov (United States)

    Andres, D.; Kartsovnik, M. V.; Biberacher, W.; Neumaier, K.; Sheikin, I.; Müller, H.; Kushch, N. D.

    2011-10-01

    Successive magnetic-field-induced charge-density-wave transitions in the layered molecular conductor α-(BEDT-TTF)2KHg(SCN)4 are studied in a hydrostatic pressure regime in which the zero field charge-density- wave (CDW) state is completely suppressed. It is shown that the orbital effect of the magnetic field restores the density wave, while orbital quantization induces transitions between different CDW states as the field strength is varied. The latter show up as distinct anomalies in the magnetoresistance as a function of field. The interplay between the orbital and Pauli paramagnetic effects, which act, respectively, to enhance and to suppress the CDW instability, is particularly manifest in the angular dependence of the field-induced anomalies.

  10. Field test of two high-pressure, direct-contact downhole steam generators. Volume I. Air/diesel system

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, B.W.

    1983-05-01

    As a part of the Project DEEP STEAM to develop technology to more efficiently utilize steam for the recovery of heavy oil from deep reservoirs, a field test of a downhole steam generator (DSG) was performed. The DSG burned No. 2 diesel fuel in air and was a direct-contact, high pressure device which mixed the steam with the combustion products and injected the resulting mixture directly into the oil reservoir. The objectives of the test program included demonstration of long-term operation of a DSG, development of operational methods, assessment of the effects of the steam/combustion gases on the reservoir and comparison of this air/diesel DSG with an adjacent oxygen/diesel direct contact generator. Downhole operation of the air/diesel DSG was started in June 1981 and was terminated in late February 1982. During this period two units were placed downhole with the first operating for about 20 days. It was removed, the support systems were slightly modified, and the second one was operated for 106 days. During this latter interval the generator operated for 70% of the time with surface air compressor problems the primary source of the down time. Thermal contact, as evidenced by a temperature increase in the production well casing gases, and an oil production increase were measured in one of the four wells in the air/diesel pattern. Reservoir scrubbing of carbon monoxide was observed, but no conclusive data on scrubbing of SO/sub x/ and NO/sub x/ were obtained. Corrosion of the DSG combustor walls and some other parts of the downhole package were noted. Metallurgical studies have been completed and recommendations made for other materials that are expected to better withstand the downhole combustion environment. 39 figures, 8 tables.

  11. Survey of welding processes for field fabrication of 2 1/4 Cr-1 Mo steel pressure vessels. [128 references

    Energy Technology Data Exchange (ETDEWEB)

    Grotke, G.E.

    1980-04-01

    Any evaluation of fabrication methods for massive pressure vessels must consider several welding processes with potential for heavy-section applications. These include submerged-arc and shielded metal-arc, narrow-joint modifications of inert-gas metal-arc and inert-gas tungsten-arc processes, electroslag, and electron beam. The advantage and disadvantages of each are discussed. Electroslag welding can be dropped from consideration for joining of 2 1/4 Cr-1 Mo steel because welds made with this method do not provide the required mechanical properties in the welded and stress relieved condition. The extension of electron-beam welding to sections as thick as 4 or 8 inches (100 or 200 mm) is too recent a development to permit full evaluation. The manual shielded metal-arc and submerged-arc welding processes have both been employed, often together, for field fabrication of large vessels. They have the historical advantage of successful application but present other disadvantages that make them otherwise less attractive. The manual shielded metal-arc process can be used for all-position welding. It is however, a slow and expensive technique for joining heavy sections, requires large amounts of skilled labor that is in critically short supply, and introduces a high incidence of weld repairs. Automatic submerged-arc welding has been employed in many critical applications and for welding in the flat position is free of most of the criticism that can be leveled at the shielded metal-arc process. Specialized techniques have been developed for horizontal and vertical position welding but, used in this manner, the applications are limited and the cost advantage of the process is lost.

  12. The respective effect of under-rib convection and pressure drop of flow fields on the performance of PEM fuel cells

    Science.gov (United States)

    Wang, Chao; Zhang, Qinglei; Shen, Shuiyun; Yan, Xiaohui; Zhu, Fengjuan; Cheng, Xiaojing; Zhang, Junliang

    2017-03-01

    The flow field configuration plays an important role on the performance of proton exchange membrane fuel cells (PEMFCs). For instance, channel/rib width and total channel cross-sectional area determine the under-rib convection and pressure drop respectively, both of which directly influence the water removal, in turn affecting the oxygen supply and cathodic oxygen reduction reaction. In this study, effects of under-rib convection and pressure drop on cell performance are investigated experimentally and numerically by adjusting the channel/rib width and channel cross-sectional area of flow fields. The results show that the performance differences with various flow field configurations mainly derive from the oxygen transport resistance which is determined by the water accumulation degree, and the cell performance would benefit from the narrower channels and smaller cross sections. It reveals that at low current densities when water starts to accumulate in GDL at under-rib regions, the under-rib convection plays a more important role in water removal than pressure drop does; in contrast, at high current densities when water starts to accumulate in channels, the pressure drop dominates the water removal to facilitate the oxygen transport to the catalyst layer.

  13. The respective effect of under-rib convection and pressure drop of flow fields on the performance of PEM fuel cells

    Science.gov (United States)

    Wang, Chao; Zhang, Qinglei; Shen, Shuiyun; Yan, Xiaohui; Zhu, Fengjuan; Cheng, Xiaojing; Zhang, Junliang

    2017-01-01

    The flow field configuration plays an important role on the performance of proton exchange membrane fuel cells (PEMFCs). For instance, channel/rib width and total channel cross-sectional area determine the under-rib convection and pressure drop respectively, both of which directly influence the water removal, in turn affecting the oxygen supply and cathodic oxygen reduction reaction. In this study, effects of under-rib convection and pressure drop on cell performance are investigated experimentally and numerically by adjusting the channel/rib width and channel cross-sectional area of flow fields. The results show that the performance differences with various flow field configurations mainly derive from the oxygen transport resistance which is determined by the water accumulation degree, and the cell performance would benefit from the narrower channels and smaller cross sections. It reveals that at low current densities when water starts to accumulate in GDL at under-rib regions, the under-rib convection plays a more important role in water removal than pressure drop does; in contrast, at high current densities when water starts to accumulate in channels, the pressure drop dominates the water removal to facilitate the oxygen transport to the catalyst layer. PMID:28251983

  14. Are changes of the geomagnetic field intensity related to changes of the tropical Pacific sea-level pressure during the last 50 years?

    Science.gov (United States)

    Vieira, Luis Eduardo Antunes; da Silva, Ligia Alves; Guarnieri, Fernando LuíS.

    2008-08-01

    The influence of solar variability into the lower atmospheric regions has been suggested on different atmospheric parameters in different time scales. However, a plausible mechanism to explain these observations remains unclear. Although it is widely accepted that the climate change over the past 50 years is attributed to human influence, we present the case that local climate change in the tropical Pacific may be due to changes in the Earth's magnetic field strength. The changes in the tropical Pacific circulation have been observed during the last 50 years, and they are attributed to the increase of the global surface temperature. However, a geomagnetic modulation of the net radiative flux in the southern tropical Pacific was recently suggested. Moreover, comparisons of long-term reconstructions of the Northern Hemisphere surface temperature and solar activity proxies indicated that the existence of a geomagnetic signal in climate data would support a direct link between solar variability and their effects on climate. Here we show that in the tropical Pacific the sea-level pressure, which is a component of the Walker circulation, could be related to the magnetospheric, ionospheric, and upper-atmosphere processes which may propagate downward to the lower atmosphere. Furthermore, we show that the changes in sea-level pressure and the Walker circulation are correlated to the westward drift of the magnetic anomaly. We compare the region averaged monthly values of the sea-level pressure in the tropical Pacific with those of the magnetic field intensity near the surface for the last 50 years. We find that the sea-level pressure in the tropical Pacific is increasing as the magnetic field intensity is decreasing. The correlation coefficient of the sea-level pressure 36-month running means versus the magnetic field intensity is 0.96. We anticipate our investigation to be a starting point for a more sophisticated investigation of the coupling between the space weather

  15. Magnetic and electric fields associated with changes in high pore pressure in fault zones: Application to the Loma Prieta ULF emissions

    Science.gov (United States)

    Fenoglio, Mark A.; Johnston, Malcom J. S.; Byerlee, Jim D.

    1995-07-01

    We determined the electric and magnetic fields generated during failure of faults containing sealed compartments with pore pressures ranging from hydrostatic to lithostatic levels. Exhumed fault studies and strain measurement data limit the possible size of these compartments to less than 1 km in extent. Rupture of seals between compartments produces rapid pore pressure changes and fluid flow and may create fractures that propagate away from the high-pressure compartment, along the fault face. Nonuniform fluid flow results from pressure decrease in the fracture from crack-generated dilatancy, partial blockage by silica deposition, and clearing as pressure increases. A direct consequence of this unsteady fluid flow may be associated transient magnetic signals caused by electrokinetic, piezomagnetic, and magnetohydrodynamic effects. Models of these processes for fault geometries with 1-km-high pressure compartments show that electrokinetic effects are several orders of magnitude larger than the other mechanisms. The electrokinetic signals produced by this unsteady flow are comparable in magnitude and frequency to the magnetic signals observed prior to the ML 7.1 Loma Prieta earthquake of October 18, 1989, provided fracture lengths are less than 200 m.

  16. Towards direct realisation of the SI unit of sound pressure in the audible hearing range based on optical free-field acoustic particle measurements

    Energy Technology Data Exchange (ETDEWEB)

    Koukoulas, Triantafillos, E-mail: triantafillos.koukoulas@npl.co.uk; Piper, Ben [Acoustics Group, National Physical Laboratory, Hampton Road, Teddington, Middlesex TW11 0LW (United Kingdom)

    2015-04-20

    Since the introduction of the International System of Units (the SI system) in 1960, weights, measures, standardised approaches, procedures, and protocols have been introduced, adapted, and extensively used. A major international effort and activity concentrate on the definition and traceability of the seven base SI units in terms of fundamental constants, and consequently those units that are derived from the base units. In airborne acoustical metrology and for the audible range of frequencies up to 20 kHz, the SI unit of sound pressure, the pascal, is realised indirectly and without any knowledge or measurement of the sound field. Though the principle of reciprocity was originally formulated by Lord Rayleigh nearly two centuries ago, it was devised in the 1940s and eventually became a calibration standard in the 1960s; however, it can only accommodate a limited number of acoustic sensors of specific types and dimensions. International standards determine the device sensitivity either through coupler or through free-field reciprocity but rely on the continuous availability of specific acoustical artefacts. Here, we show an optical method based on gated photon correlation spectroscopy that can measure sound pressures directly and absolutely in fully anechoic conditions, remotely, and without disturbing the propagating sound field. It neither relies on the availability or performance of any measurement artefact nor makes any assumptions of the device geometry and sound field characteristics. Most importantly, the required units of sound pressure and microphone sensitivity may now be experimentally realised, thus providing direct traceability to SI base units.

  17. 基于GIS的矿山地表移动信息管理与分析系统%GIS BASED INFORMATION MANAGEMENT AND ANALYZING SYSTEM FOR GROUND SURFACE MOVEMENT AT MINES

    Institute of Scientific and Technical Information of China (English)

    邓清海; 马凤山; 袁仁茂; 丁德民; 张亚民; 王杰; 郭捷

    2009-01-01

    In accordance with engineering practice of Jinchuan Nickel Mine in Gansu Province, China, this paper studies the method and process of developing ground surface movement information management and analyzing system for mines. The system is a GIS based secondary development. The paper discusses the structure and functions of the system. The system contains three modules: management of ground surface movement information, analysis and evaluation of ground surface movement, and ground surface movement forecast. The system makes the best of powerful information management and spatial analyzing capabilities of GIS, and can carry out the analysis and evaluation of ground surface movement by combining Surfer 8.0. And in the module of forecast, using the technique of MATLAB 6.5 program with VB 6.0, the system can achieve the ANN prediction model for GPS monitoring data. The study results shall improve management and analyzing efficiency for ground surface movement information in Jinchuan Nickel Mine, and can be used in developing the information system of ground surface movement in other mines.%以金川矿区为例,介绍了应用GIS进行二次开发来构建矿山地表移动信息管理与分析系统的方法、过程以及该系统的主要功能.该系统包括地表移动信息管理、地表移动分析与评价、地表移动预测3个模块,充分利用了GIS强大的空间数据管理与分析能力,实现了GIS与Surfer结合进行矿山地表移动分析与评价,GIS与Matlab结合进行监测数据的非线性神经网络时序预测.该系统不但有助于提高金川矿山地表移动信息的检索和分析效率,对其他矿山地表移动信息系统的建立也具有借鉴意义.

  18. 地表水文监测在岩溶隧道施工中的应用%Application of Ground Surface Hydrology Monitoring in Construction of Karst Tunnels

    Institute of Scientific and Technical Information of China (English)

    周坤; 方俊波

    2013-01-01

    为探讨岩溶隧道施工涌水对地表水文环境的影响程度及范围,以圆梁山深埋特长隧道工程施工为依托,对隧道地表水文进行监测和分析.主要研究内容及结论为:1)介绍圆梁山隧道向斜段地表水文地质情况,说明进行悬挂泉流量及地表井泉水位监测可以评估隧道突涌水对地表环境的影响程度及范围;2)进行地表大气降雨及隧道涌水量观测并对比,可以据此判定隧道与地表的水力连通性;3)证明隧道施工会对隧道洞身上方泉眼产生影响,但对山顶植被影响较轻;4)在岩溶隧道施工中进行地表水文监测是必要的,对施工具有指导作用.%The ground surface hydrology of Yuanliangshan deep-buried extra-long tunnel is monitored and analyzed,so as to obtain the degree and range of the influence on the ground surface hydrology imposed by water burst occurring during the construction of karst tunnels.Conclusions drawn are as follows:1) The degree and range of the influence of water bursts on the ground surface hydrology can be evaluated by means of monitoring the flow volume of hanging springs and the water levels of ground surface well springs.2) The hydraulic conductivity between the tunnel and the ground surface can be deduced from monitoring of and comparison and contrast between ground surface rainfalls and water bursts.3) The tunnel construction has some influence on the springs above the tunnel,but has little influence on the vegetations.4) It is necessary to monitor the ground surface hydrology,which can provide reference for the construction of karst tunnels.

  19. Initial Pressure Distribution in the Geothermal Field of Los Humeros, Puebla, Mexico; Distribucion de presion inicial en el campo geotermico de Los Humeros, Puebla, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Arellano, Victor M.; Izquierdo, Georgina; Aragon, Alfonso; Barragan, Rosa Maria; Garcia, Alfonso [Instituto de Investigaciones Electricas (Mexico); Pizano, Arturo [Comision Federal de Electricidad (Mexico)

    2001-09-01

    To obtain the undisturbed distribution of pressures of a field flow, a significant amount of data concerning geological, geochemical, geophysical, and field drilling and engineering aspects, from 42 wells located at the geothermal field of Los Humeros, was analysed. Based on the studied data, models of the field pressure distribution in its initial state were developed. The models reveal the existence of at least two deposits. One of them, the most superficial, is located between 1025 and 1600 meters over the sea level, and from its excellent congruence with the pressure profile of a boiling water column, it may be considered as a predominantly liquid field. The pressure profile of this field is that of a boiling water column, at a temperature of about 300-330 Celsius degrees. The second field is below 850 meters over the sea level and from the known data it reaches at least 100 meters over the sea level. It is considered a low-liquid saturated field. The temperatures of the wells supplied by this field were estimated to be about 300-40 Celsius degrees. [Spanish] Para inferir las distribuciones de presion no perturbadas del fluido del yacimiento, se analizo una considerable cantidad de informacion relacionada con los aspectos geologicos, geoquimicos, geofisicos, de perforacion e ingenieria de yacimientos, correspondiente a 42 pozos del camo geotermico de Los Humeros, Puebla. Sobre la base de los datos analizados se desarrollaron modelos de distribucion de la presion del yacimiento en su estado inicial. Dichos modelos revelan la existencia de, cuando menos, dos yacimientos. El primero y mas superficial se encuentra localizado entre 1,600 y 1,025 metros sobre el nivel del mar (msnm), y dada su excelente concordancia con el perfil de presion correspondiente a una columna de agua en ebullicion, puede afirmarse que se trata de un yacimiento de liquido dominante. El perfil de presion de este yacimiento corresponde a una columna de agua en ebullicion de 300 a 330

  20. Geophysical investigation of the pressure field produced by water guns at a pond site in La Crosse, Wisconsin

    Science.gov (United States)

    Adams, Ryan F.; Morrow, William S.

    2015-09-03

    Three different geophysical sensor types were used to characterize the underwater pressure waves generated by the underwater firing of a seismic water gun and their suitability for establishing a pressure barrier to potentially direct or prevent the movement of the Asian carps. The sensors used to collect the seismic information were blast rated hydrophones and underwater blast sensors. Specific location information for the water guns and the sensors was obtained using either laser rangefinders or differentially corrected global positioning systems (GPS).

  1. Modeling Seafloor Deformation at the TAG Hydrothermal Field: Feedbacks between Permeability and Poroelastic Fluid Flow?

    Science.gov (United States)

    Crone, T. J.; Sohn, R. A.; Barreyre, T.

    2014-12-01

    Recent measurements of ocean bottom pressure suggest that hydrothermal flow induces cm-scale periodic ground surface displacement (GSD) at the Trans-Atlantic Geotraverse (TAG) hydrothermal field on the Mid-Atlantic Ridge (Sohn et al., 2009). The pressure measurements contain spectral peaks and harmonics with periods ranging from 22 to 53 min, none of which can be attributed to oceanographic or Earth tide processes. It is hypothesized that GSD cycles in this system may result from a nonlinear feedback between pore pressure and permeability in the hydrothermal system. To test this hypothesis we have developed a poroelastic convection model representing the upper crustal section at TAG that includes a "switching" type pressure-permeability feedback in the stockwork zone of the hydrothermal system. In this zone, the permeability increases when the pressure reaches a critical high value, and decreases when it reaches a critical low value. This behavior simulates the opening and closing of cracks within the hydrothermal system, and is similar to mechanisms that have been proposed for dike propagation in magmatic systems (Buck et al., 2006). Our modeling suggests that this mechanism can generate GSD that are similar to those observed at TAG. We are currently using these models to explore the sensitivity of inflation and deflation rates to system properties such as the geometry of the stockwork zone, the temperature of fluid in the upflow zone, the elastic properties of the lithosphere, and the relationship between pore pressure and permeability.

  2. Influence of shock wave pressure amplitude and pulse repetition frequency on the lifespan, size and number of transient cavities in the field of an electromagnetic lithotripter

    Science.gov (United States)

    Huber, Peter; Jöchle, Knut; Debus, Jürgen

    1998-10-01

    Monitoring the generation of cavitation is of great interest for diagnostic and therapeutic use of ultrasound in medicine, since cavitation is considered to play a major role in nonthermal ultrasound interactions with tissue. Important parameters are the number of cavitation events and the energy released during the bubble collapse. This energy is correlated to the maximum bubble radius which is related to the cavitation lifespan. The aim of this study was therefore to investigate the influence of the acoustic pressure amplitude and the pulse repetition frequency (PRF) in the field of a lithotripter (Lithostar, Siemens) on the number, size and lifespan of transient cavitation bubbles in water. We used scattered laser light recorded by a photodiode and stroboscopic photographs to monitor the cavitation activity. We found that PRF (range 0.5-5 Hz) had no influence on the cavitation bubble lifespan and size, whereas lifespan and size increased with the acoustic pressure amplitude. In contrast, the number of cavitation events strongly increased with PRF, whereas the pressure amplitude had no significant influence on the number of cavitation events. Thus, by varying the pressure amplitude and PRF, it might be possible to deliver a defined relative number of cavitations at a defined relative energy level in a defined volume. This seems to be relevant to further studies that address the biological effects of transient cavitation occurring in the fields of lithotripters.

  3. Low temperature carrier transport study of monolayer MoS{sub 2} field effect transistors prepared by chemical vapor deposition under an atmospheric pressure

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xinke, E-mail: xkliu@szu.edu.cn, E-mail: wujing026@gmail.com; He, Jiazhu; Tang, Dan; Lu, Youming; Zhu, Deliang; Liu, Wenjun; Cao, Peijiang; Han, Sun [College of Materials Science and Engineering, Shenzhen Engineering Laboratory for Advanced Technology of Ceramics, Nanshan District Key Lab for Biopolymer and Safety Evaluation, Shenzhen University, 3688 Nanhai Ave, Shenzhen 518060 (China); Liu, Qiang; Wen, Jiao; Yu, Wenjie [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, CAS, 865 Chang Ning Road, Shanghai 200050 (China); Liu, Wenjun [State Key Laboratory of ASIC and System, Department of Microelectronics, Fudan University, 220 Handan Road, Shanghai 200433 (China); Wu, Jing, E-mail: xkliu@szu.edu.cn, E-mail: wujing026@gmail.com [Department of Physics, National University of Singapore, 21 Lower Kent Ridge Road, 117576 Singapore (Singapore); He, Zhubing [Department of Materials Science and Engineering, South University of Science and Technology of China, 1088 Xueyuan Road, Shenzhen 518055 (China); Ang, Kah-Wee [Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, 117583 Singapore (Singapore)

    2015-09-28

    Large size monolayer Molybdenum disulphide (MoS{sub 2}) was successfully grown by chemical vapor deposition method under an atmospheric pressure. The electrical transport properties of the fabricated back-gate monolayer MoS{sub 2} field effect transistors (FETs) were investigated under low temperatures; a peak field effect mobility of 59 cm{sup 2}V{sup −1}s{sup −1} was achieved. With the assist of Raman measurement under low temperature, this work identified the mobility limiting factor for the monolayer MoS{sub 2} FETs: homopolar phonon scattering under low temperature and electron-polar optical phonon scattering at room temperature.

  4. Donor impurity-related linear and nonlinear intraband optical absorption coefficients in quantum ring: effects of applied electric field and hydrostatic pressure.

    Science.gov (United States)

    Barseghyan, Manuk G; Restrepo, Ricardo L; Mora-Ramos, Miguel E; Kirakosyan, Albert A; Duque, Carlos A

    2012-09-28

    : The linear and nonlinear intraband optical absorption coefficients in GaAs three-dimensional single quantum rings are investigated. Taking into account the combined effects of hydrostatic pressure and electric field, applied along the growth direction of the heterostructure, the energies of the ground and first excited states of a donor impurity have been found using the effective mass approximation and a variational method. The energies of these states are examined as functions of the dimensions of the structure, electric field, and hydrostatic pressure. We have also investigated the dependencies of the linear, nonlinear, and total optical absorption coefficients as a function of incident photon energy for several configurations of the system. It is found that the variation of distinct sizes of the structure leads to either a redshift and/or a blueshift of the resonant peaks of the intraband optical spectrum. In addition, we have found that the application of an electric field leads to a redshift, whereas the influence of hydrostatic pressure leads to a blueshift (in the case of on-ring-center donor impurity position) of the resonant peaks of the intraband optical spectrum.

  5. Upper critical field, pressure-dependent superconductivity and electronic anisotropy of Sm4Fe2As2Te(1-x)O(4-y)F(y).

    Science.gov (United States)

    Pisoni, A; Katrych, S; Szirmai, P; Náfrádi, B; Gaál, R; Karpinski, J; Forró, L

    2016-03-23

    We present a detailed study of the electrical transport properties of a recently discovered iron-based superconductor: Sm4Fe2As2Te0.72O2.8F1.2. We followed the temperature dependence of the upper critical field by resistivity measurement of single crystals in magnetic fields up to 16 T, oriented along the two main crystallographic directions. This material exhibits a zero-temperature upper critical field of 90 T and 65 T parallel and perpendicular to the Fe2As2 planes, respectively. An unprecedented superconducting magnetic anisotropy γH=H(c2)(ab)/H(c2)(c) ~ 14 is observed near Tc, and it decreases at lower temperatures as expected in multiband superconductors. Direct measurement of the electronic anisotropy was performed on microfabricated samples, showing a value of ρ(c)/ρ(ab)(300K) ~ 5 that rises up to 19 near Tc . Finally, we have studied the pressure and temperature dependence of the in-plane resistivity. The critical temperature decreases linearly upon application of hydrostatic pressure (up to 2 GPa) similarly to overdoped cuprate superconductors. The resistivity shows saturation at high temperatures, suggesting that the material approaches the Mott-Ioffe-Regel limit for metallic conduction. Indeed, we have successfully modelled the resistivity in the normal state with a parallel resistor model that is widely accepted for this state. All the measured quantities suggest strong pressure dependence of the density of states.

  6. Pressure-Induced Shifts of R, R', and B Line-Groups and Ground-State Zero-Field-Splitting of Ruby

    Institute of Scientific and Technical Information of China (English)

    MA Dong-Ping; CHEN Ju-Rong

    2005-01-01

    By means of improved ligand-field theory, the "pure electronic" presure-induced shifts (PS's) and the PS's due to electron-phonon interaction (EPI) of the R1, R2, B1, B2, B3, and R'3 lines and the ground-state zero-field-splitting of ruby have been uniformly calculated. The calculation results are in very good agreement with all the experimental data. At normal pressure, ruby is a crystal with very strong crystal field. Thus, the admixture of |t22 (3T1)e4T2> and |t3 2 2 E> bases in the wavefunction of R1 level of ruby is small at normal pressure, and it gradually decreases with increasing pressure, which causes the R1-line PS of ruby to monotonously red shift with approximate linearity. The combined effect of the pure electronic PS of R1 line and the PS of R1 line due to EPI gives rise to the total PS of R1 line. The analyses and comparisons among the features of R1-line PS's of three laser crystals (ruby, GSGG:Cr3+ and GGG:Cr3+ ) have been made, and the origin of their difference has been revealed.

  7. Analysis of flow field and pressure loss of automotive mufflers%汽车消声器的流场和压力损失分析

    Institute of Scientific and Technical Information of China (English)

    许建民

    2011-01-01

    In this paper, three-dimensional steady flow numerical simulation of the velocity field and pressure field of two different forms of double cavity expansion muffler was performed by using the CFD (computational fluid dynamic method) software FLUENT, and how the pressure loss changes with the velocity of the entry was studied. Simulation results show that the internal flow field of double cavity expansion muffler is very complex; the position and number of connecting pipe has great effect on the pressure loss of the muffler; the resistance loss of the dual connecting pipe is greater than that of the single connection pipe.%采用CFD软件Fluent对两种不同结构形式的双扩张腔消声器的速度场、压力场进行三维稳态流动数值模拟,研究相应的压力损失随入口流速的变化趋势.结果表明,双扩张腔消声器内部流场非常复杂,中间连通管的位置和数量对消声器内气体的压力损失有很大的影响,双连通管消声器内的压力损失比单连通管的要大.

  8. Monitoring of ground surface deformation in mining area with InSAR technique%利用InSAR技术监测矿区地表形变

    Institute of Scientific and Technical Information of China (English)

    朱建军; 邢学敏; 胡俊; 李志伟

    2011-01-01

    The application status and research progress of InSAR technique in the monitoring of the ground surface deformation in mining area were introduced. Firstly, the advantages of D-InSAR technique were analyzed by comparing to the traditional surveying methods. Then, the limitations of D-InSAR in the mining deformation detection were described. According to the limitations of the traditional D-InSAR method, the advanced InSAR technique, e.g., small baseline subset (SBAS), permanent scatterer (PS) and corner reflector (CR) techniques were discussed. Using real mining subsidence monitoring as example, the characteristics and application status of those advanced InSAR techniques were studied, and the key problems still existing in the current research were summarized. Finally, it is indicated that the development trend of InSAR monitoring surface deformation in mining area is the combination of advanced InSAR and high-resolution SAR images.%介绍了InSAR技术在矿区地表形变监测中的应用现状及进展,分析了D-InSAR技术相比于传统测量手段的优势,并指出其在矿区地表形变监测中的不足.针对传统D-InSAR技术的局限性,重点讨论了短基线(SBAS)、永久散射体(PS)和角反射器(CR)等高级差分干涉技术,并结合矿区沉降监测实例,分析了其特点与应用现状,讨论了现有研究中仍存在的问题.高级InSAR技术和高分辨率SAR影像的结合将是矿区地表形变监测的发展趋势.

  9. Calculation of Annulus Pressure on Managed Pressure Drilling in Daqing Oil Field%大庆油田控压钻井作业环空压力的计算

    Institute of Scientific and Technical Information of China (English)

    李士斌; 周艳; 邸百英; 宋瑞宏

    2011-01-01

    根据Beggs-Brill的流动型态模型推导出了控制压力钻井环空多相流的压力计算公式;并提出了井口回压对环空流态的影响.提出的计算模型已通过现场试验的验证.试验结果表明其误差只有3%左右,能够指导现场作业.为控制压力钻井技术在大庆油田的应用和发展提供理论依据.%According to the mobile state model of Beggs-Brill to infer the multiphase calculation formula of manage pressure drilling, the well head back pressure influence the annulus state is proposed. The computation model is proposed through the field test confirmation. The test result has indicated its error only then about 3%, could instruct the field operation. The theory basis for MPD in the Daqing Oil Field application and the development is provided.

  10. Magnetic field effects on the vestibular system: calculation of the pressure on the cupula due to ionic current-induced Lorentz force

    Science.gov (United States)

    Antunes, A.; Glover, P. M.; Li, Y.; Mian, O. S.; Day, B. L.

    2012-07-01

    Large static magnetic fields may be employed in magnetic resonance imaging (MRI). At high magnetic field strengths (usually from about 3 T and above) it is possible for humans to perceive a number of effects. One such effect is mild vertigo. Recently, Roberts et al (2011 Current Biology 21 1635-40) proposed a Lorentz-force mechanism resulting from the ionic currents occurring naturally in the endolymph of the vestibular system. In the present work a more detailed calculation of the forces and resulting pressures in the vestibular system is carried out using a numerical model. Firstly, realistic 3D finite element conductivity and fluid maps of the utricle and a single semi-circular canal containing the current sources (dark cells) and sinks (hair cells) of the utricle and ampulla were constructed. Secondly, the electrical current densities in the fluid are calculated. Thirdly, the developed Lorentz force is used directly in the Navier-Stokes equation and the trans-cupular pressure is computed. Since the driving force field is relatively large in comparison with the advective acceleration, we demonstrate that it is possible to perform an approximation in the Navier-Stokes equations that reduces the problem to solving a simpler Poisson equation. This simplification allows rapid and easy calculation for many different directions of applied magnetic field. At 7 T a maximum cupula pressure difference of 1.6 mPa was calculated for the combined ampullar (0.7 µA) and utricular (3.31 µA) distributed current sources, assuming a hair-cell resting current of 100 pA per unit. These pressure values are up to an order of magnitude lower than those proposed by Roberts et al using a simplistic model and calculation, and are in good agreement with the estimated pressure values for nystagmus velocities in caloric experiments. This modeling work supports the hypothesis that the Lorentz force mechanism is a significant contributor to the perception of magnetic field induced vertigo.

  11. Magnetic field effects on the vestibular system: calculation of the pressure on the cupula due to ionic current-induced Lorentz force.

    Science.gov (United States)

    Antunes, A; Glover, P M; Li, Y; Mian, O S; Day, B L

    2012-07-21

    Large static magnetic fields may be employed in magnetic resonance imaging (MRI). At high magnetic field strengths (usually from about 3 T and above) it is possible for humans to perceive a number of effects. One such effect is mild vertigo. Recently, Roberts et al (2011 Current Biology 21 1635-40) proposed a Lorentz-force mechanism resulting from the ionic currents occurring naturally in the endolymph of the vestibular system. In the present work a more detailed calculation of the forces and resulting pressures in the vestibular system is carried out using a numerical model. Firstly, realistic 3D finite element conductivity and fluid maps of the utricle and a single semi-circular canal containing the current sources (dark cells) and sinks (hair cells) of the utricle and ampulla were constructed. Secondly, the electrical current densities in the fluid are calculated. Thirdly, the developed Lorentz force is used directly in the Navier-Stokes equation and the trans-cupular pressure is computed. Since the driving force field is relatively large in comparison with the advective acceleration, we demonstrate that it is possible to perform an approximation in the Navier-Stokes equations that reduces the problem to solving a simpler Poisson equation. This simplification allows rapid and easy calculation for many different directions of applied magnetic field. At 7 T a maximum cupula pressure difference of 1.6 mPa was calculated for the combined ampullar (0.7 µA) and utricular (3.31 µA) distributed current sources, assuming a hair-cell resting current of 100 pA per unit. These pressure values are up to an order of magnitude lower than those proposed by Roberts et al using a simplistic model and calculation, and are in good agreement with the estimated pressure values for nystagmus velocities in caloric experiments. This modeling work supports the hypothesis that the Lorentz force mechanism is a significant contributor to the perception of magnetic field induced vertigo.

  12. Development of automated welding process for field fabrication of thick walled pressure vessels. Fourth quarter, FY 1980

    Energy Technology Data Exchange (ETDEWEB)

    1980-12-19

    Progress is reported in research on the automated welding of heavy steel plate for the fabrication of pressure vessels. Information is included on: torch and shield adaptation; mechanical control of the welding process; welding parameters; joint design; filler wire optimizaton; nondestructive testing of welds; and weld repair. (LCL)

  13. 27.3-day and Average 13.6-day Periodic Oscillations in the Earth's Rotation Rate and Atmospheric Pressure Fields Due to Celestial Gravitation Forcing

    Institute of Scientific and Technical Information of China (English)

    LI Guoqing; ZONG Haifeng; ZHANG Qingyun

    2011-01-01

    Variation in length of day of the Earth (LOD equivalent to the Earth's rotation rate) versus change in atmospheric geopotential height fields and astronomical parameters were analyzed for the years 1962-2006.This revealed that there is a 27.3-day and an average 13.6-day periodic oscillation in LOD and atmospheric pressure fields following lunar revolution around the Earth. Accompanying the alternating change in celestial gravitation forcing on the Earth and its atmosphere, the Earth's LOD changes from minimum to maximum,then to minimum. and the atmospheric geopotential height fields in the tropics oscillate from low to high,then to low. The 27.3-day and average 13.6-day periodic atmospheric oscillation in the tropics is proposed to be a type of strong atmospheric tide, excited by celestial gravitation forcing. A formula for a Tidal Index was derived to estimate the strength of the celestial gravitation forcing, and a high degree of correlation was found between the Tidal Index determined by astronomical parameters, LOD, and atmospheric geopotential height. The reason for the atmospheric tide is periodic departure of the lunar orbit from the celestial equator during lunar revolution around the Earth. The alternating asymmetric change in celestial gravitation forcing on the Earth and its atmosphere produces a "modulation" to the change in the Earth's LOD and atmospheric pressure fields.

  14. Drag with external and pressure drop with internal flows: a new and unifying look at losses in the flow field based on the second law of thermodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Herwig, Heinz; Schmandt, Bastian, E-mail: h.herwig@tuhh.de [Hamburg University of Technology, Institute for Thermo-Fluid Dynamics, Denickestr. 17, D-21073 Hamburg (Germany)

    2013-10-15

    Internal and external flows are characterized by friction factors and drag coefficients, respectively. Their definitions are based on pressure drop and drag force and thus are very different in character. From a thermodynamics point of view in both cases dissipation occurs which can uniformly be related to the entropy generation in the flow field. Therefore we suggest to account for losses in the flow field by friction factors and drag coefficients that are based on the overall entropy generation due to the dissipation in the internal and external flow fields. This second law analysis (SLA) has been applied to internal flows in many studies already. Examples of this flow category are given together with new cases of external flows, also treated by the general SLA-approach. (paper)

  15. Successful application of MPD (managed pressure drilling) for prevention, control, and detection of borehole ballooning in tight gas reservoir in Cuervito Field, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Ochoa, A.; Acevedo, O.; Nieto, L. [Petrobras (United States); Lambarria, J.E. [PEMEX Exploration and Production (Mexico); Perez, H. [Weatherford (United States)

    2011-07-01

    The Cuervito field is an oil play located in the Burgos Basin in northeastern Mexico. In order to reach the highest yielding sands, wells in the Cuervito field are usually set up with 3 casings. However, the ballooning effect, an elastoplastic behavior of a well's walls, occurs during drilling operations, leading to loss of circulation. Two methods, based on geological and geopressure data, were found to minimize this effect: either putting in an extra casing, or using an unconventional drilling technique. As the managed pressure drilling (MPD) technique is less complex and more elegant, a pilot project was implemented using this method on a well. Results showed that MPD minimized lost time and enhanced drilling efficiency. This paper demonstrated that the use of MPD in the Cuervito field is a good solution for identifying and controlling the ballooning effect and this technique was successfully applied to the next 3 wells drilled subsequently.

  16. GPU-based, parallel-line, omni-directional integration of measured acceleration field to obtain the 3D pressure distribution

    Science.gov (United States)

    Wang, Jin; Zhang, Cao; Katz, Joseph

    2016-11-01

    A PIV based method to reconstruct the volumetric pressure field by direct integration of the 3D material acceleration directions has been developed. Extending the 2D virtual-boundary omni-directional method (Omni2D, Liu & Katz, 2013), the new 3D parallel-line omni-directional method (Omni3D) integrates the material acceleration along parallel lines aligned in multiple directions. Their angles are set by a spherical virtual grid. The integration is parallelized on a Tesla K40c GPU, which reduced the computing time from three hours to one minute for a single realization. To validate its performance, this method is utilized to calculate the 3D pressure fields in isotropic turbulence and channel flow using the JHU DNS Databases (http://turbulence.pha.jhu.edu). Both integration of the DNS acceleration as well as acceleration from synthetic 3D particles are tested. Results are compared to other method, e.g. solution to the Pressure Poisson Equation (e.g. PPE, Ghaemi et al., 2012) with Bernoulli based Dirichlet boundary conditions, and the Omni2D method. The error in Omni3D prediction is uniformly low, and its sensitivity to acceleration errors is local. It agrees with the PPE/Bernoulli prediction away from the Dirichlet boundary. The Omni3D method is also applied to experimental data obtained using tomographic PIV, and results are correlated with deformation of a compliant wall. ONR.

  17. Effects of ambient and acute partial pressures of ozone on leaf net CO sub 2 assimilation of field-grown Vitis vinifera L

    Energy Technology Data Exchange (ETDEWEB)

    Roper, T.R.; Williams, L.E. (Univ. of California, Davis (USA) Kearney Agricultural Center, Parlier, CA (USA))

    1989-12-01

    Mature, field-grown Vitis vinifera L. grapevines grown in open-top chambers were exposed to either charcoal-filtered air or ambient ozone partial pressures throughout the growing season. Individual leaves also were exposed to ozone partial pressures of 0.2, 0.4, or 0.6 micropascals per pascal for 5 hours. No visual ozone damage was found on leaves exposed to any of the treatments. Chronic exposure to ambient O{sub 3} partial pressures reduced net CO{sub 2} assimilation rate (A) between 5 and 13% at various times throughout the season when compared to the filtered treatment. Exposure of leaves to 0.2 micropascals per pascal O{sub 3} for 5 hours had no significant effect on A; however, A was reduced 84% for leaves exposed to 0.6 micropascals per pascal O{sub 3} when compared to the controls after 5 hours. Intercellular CO{sub 2} partial pressure (c{sub i}) was lower for leaves exposed to 0.2 micropascals per pascal O{sub 3} when compared to the controls, while c{sub i} of the leaves treated with 0.6 micropascals per pascal of O{sub 3} increased during the fumigation. The long-term effects of ambient O{sub 3} and short-term exposure to acute levels of O{sub 3} reduced grape leaf photosynthesis due to a reduction in both stomatal and mesophyll conductances.

  18. Gas to Liquid Pressurization Technology in The Field of Engineering Application%气液增压技术在工程领域中的应用

    Institute of Scientific and Technical Information of China (English)

    张志慧; 张颖颖; 邢世杰; 许晓敏

    2012-01-01

    This paper through to the hydraulic pressure station, gas to liquid pressurization system analysis, detailed introduces the advantages and disadvantages between the two. After the check valve-steel ball being connected machine the discussion of the plan, the calculation of bending force, and proves the hydraulic and pneumatic supercharging technology in machine tools on the feasibility of application, fundamentally solve the hydraulic pressure station covers an area of big, noise shortcomings. For gas to liquid pressurization system in engineering field is used in great quantities to provide the basis.%通过对液压站,气液增压系统的分析,详细的介绍了二者之间的优缺点。经过对单向阀一钢球压装机床方案的讨论,压装力的计算,证明了气液增压技术在机床上应用的可行性,从根本上解决了液压站占地面积大,噪音大等缺点。为气液增压系统在工程领域中大量使用提供了依据。

  19. Outflow boundary conditions for 3D simulations of non-periodic blood flow and pressure fields in deformable arteries

    CERN Document Server

    Vignon-Clementel, Irene; Jansen, K E; Taylor, C A; 10.1080/10255840903413565

    2010-01-01

    The simulation of blood flow and pressure in arteries requires outflow boundary conditions that incorporate models of downstream domains. We previously described a coupled multidomain method to couple analytical models of the downstream domains with 3D numerical models of the upstream vasculature. This prior work either included pure resistance boundary conditions or impedance boundary conditions based on assumed periodicity of the solution. However, flow and pressure in arteries are not necessarily periodic in time due to heart rate variability, respiration, complex transitional flow or acute physiological changes. We present herein an approach for prescribing lumped parameter outflow boundary conditions that accommodate transient phenomena. We have applied this method to compute haemodynamic quantities in different physiologically relevant cardiovascular models, including patient-specific examples, to study non-periodic flow phenomena often observed in normal subjects and in patients with acquired or congen...

  20. Methodological developments in the field of structural integrity analyses of large scale reactor pressure vessels in Hungary

    Directory of Open Access Journals (Sweden)

    Tamás Fekete

    2016-03-01

    Full Text Available Buildings, structures and systems of large scale and high value (e.g. conventional and nuclear power plants, etc. are designed for a certain, limited service lifetime. If the standards and guidelines of the time are taken into account during the design process, the resulting structures will operate safely in most cases. However, in the course of technical history there were examples of unusual, catastrophic failures of structures, even resulting in human casualties. Although the concept of Structural Integrity first appeared in industrial applications only two-three decades ago, its pertinence has been growing higher ever since. Four nuclear power generation units have been constructed in Hungary, more than 30 years ago. In every unit, VVER-440 V213 type light-water cooled, light-water moderated, pressurized water reactors are in operation. Since the mid-1980s, Pressurized Thermal Shock (PTS analyses of Reactor Pressure Vessels (RPV have been conducted in Hungary, where the concept of structural integrity was the basis of research and development. In the first part of the paper, a short historic overview is given, where the origins of the Structural Integrity concept are presented, and the beginnings of Structural Integrity in Hungary are summarized. In the second part, a new conceptual model of Structural Integrity is introduced. In the third part, a brief description of the VVER-440 V213 type RPV and its surrounding primary system is presented. In the fourth part, a conceptual model developed for PTS Structural Integrity Analyses is explained.

  1. EXPERIMENTAL RESEARCH ON AERODYNAMIC PERFORMANCE AND EXIT FLOW FIELD OF LOW PRESSURE AXIAL FLOW FAN WITH CIRCUMFERENTIAL SKEWED BLADES

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In this article, the low pressure axial flow fan with circumferential skewed rotor blade, including the radial blade, the forward-skewed blade and the backward-skewed blade, was studied with experimental methods. The aerodynamic performance of the rotors was measured. At the design condition at outlet of the rotors, detailed flow measurements were performed with a five-hole probe and a Hot-Wire Anemometer (HWA). The results show that compared to the radial rotor, the forward-skewed rotor demonstrates a wider Stable Operating Range (SOR), is able to reduce the total pressure loss in the hub region and make main loading of blade accumulating in the mid-span region. There is a wider wake in the upper mid-span region of the forward-skewed rotor. Compared to the radial rotor, in the backward-skewed rotor there is higher total pressure loss near the hub and shroud regions and lower loss in the mid-span region. In addition, the velocity deficit in the wake is lower at mid-span of the backward-skewed rotor than the forward-skewed rotor.

  2. Hamilton--Jacobi theory for continuation of magnetic field across a toroidal surface supporting a plasma pressure discontinuity

    CERN Document Server

    McGann, M; Dewar, R L; von Nessi, G

    2010-01-01

    The vanishing of the divergence of the total stress tensor (magnetic plus kinetic) in a neighborhood of an equilibrium plasma containing a toroidal surface of discontinuity gives boundary and jump conditions that strongly constrain allowable continuations of the magnetic field across the surface. The boundary conditions allow the magnetic fields on either side of the discontinuity surface to be described by surface magnetic potentials, reducing the continuation problem to that of solving a Hamilton--Jacobi equation. The characteristics of this equation obey Hamiltonian equations of motion, and a necessary condition for the existence of a continued field across a general toroidal surface is that there exist invariant tori in the phase space of this Hamiltonian system. It is argued from the Birkhoff theorem that existence of such an invariant torus is also, in general, sufficient for continuation to be possible. An important corollary is that the rotational transform of the continued field on a surface of disco...

  3. Topological basis for understanding the behavior of the heavy-fermion metal β -YbAlB4 under application of magnetic field and pressure

    Science.gov (United States)

    Shaginyan, V. R.; Msezane, A. Z.; Popov, K. G.; Clark, J. W.; Khodel, V. A.; Zverev, M. V.

    2016-05-01

    Informative recent measurements on the heavy-fermion metal β -YbAlB4 performed with applied magnetic field and pressure as control parameters are analyzed with the goal of establishing a sound theoretical explanation for the inferred scaling laws and non-Fermi-liquid (NFL) behavior, which demonstrate some unexpected features. Most notably, the robustness of the NFL behavior of the thermodynamic properties and of the anomalous T3 /2 temperature dependence of the electrical resistivity under applied pressure P in zero magnetic field is at variance with the fragility of the NFL phase under application of a field B . We show that a consistent topological basis for this combination of observations, as well as the empirical scaling laws, may be found within fermion-condensation theory in the emergence and destruction of a flat band, and explains that the paramagnetic NFL phase takes place without magnetic criticality, not from quantum critical fluctuations. Schematic T -B and T -P phase diagrams are presented to illuminate this scenario.

  4. Pressure sensor

    Science.gov (United States)

    Mee, David K.; Ripley, Edward B.; Nienstedt, Zachary C.; Nienstedt, Alex W.; Howell, Jr., Layton N.

    2015-09-29

    Disclosed is a passive, in-situ pressure sensor. The sensor includes a sensing element having a ferromagnetic metal and a tension inducing mechanism coupled to the ferromagnetic metal. The tension inducing mechanism is operable to change a tensile stress upon the ferromagnetic metal based on a change in pressure in the sensing element. Changes in pressure are detected based on changes in the magnetic switching characteristics of the ferromagnetic metal when subjected to an alternating magnetic field caused by the change in the tensile stress. The sensing element is embeddable in a closed system for detecting pressure changes without the need for any penetrations of the system for power or data acquisition by detecting changes in the magnetic switching characteristics of the ferromagnetic metal caused by the tensile stress.

  5. Use of the crop maize to reduce yellow nutsedge (Cyperus esculentus L. pressure in highly infested fields in Switzerland

    Directory of Open Access Journals (Sweden)

    Keller, Martina

    2014-02-01

    Full Text Available Cyperus esculentus L. causes high yield losses in many crops worldwide. In Switzerland it was observed for the first time about 30 years ago. Since then it has become a serious weed in several regions - especially where vegetables are produced. Growing vegetables in heavily infested fields should be abandoned due to their low competitiveness and the lack of available, effective herbicides. Contrarily, in maize several herbicides with a partial effect on C. esculentus are registered. Thus, continuous cultivation of maize including the use of the most effective herbicides against C. esculentus could help reducing infestation levels in heavily infested fields. Field trials were carried out at two sites in maize during 2011 and 2012. Different herbicide combinations, hoeing and herbicide applications combined with hoeing were the applied treatments. Split application was compared with one single application of the same amount of product. The effect of an additional, late under leaf herbicide application was determined as well. Cyperus esculentus coverage was estimated in the fields in 2011. Plots were sampled in spring 2011, autumn 2011 and autumn 2012. The Number of C. esculentus sprouts germinated from the soil samples was determined under greenhouse conditions. The most effective herbicide combination of registered active ingredients was rimsulfuron and mesotrione. Smetolachlor was effective as well, especially if combined with mechanical weed control. Halosulfuron-methyl applied twice provided the best C. esculentus control. Split application tended to be more effective than a single application. Control of C. esculentus could be improved considerably with an additional herbicide application in late June (under leaf. The treatments with highest C. esculentus control determined in the field trials and combinations thereof are effective treatment options for C. esculentus control in maize. These findings indicate and confirm that maize cropped for

  6. A pressure-driven model for the quasi periodical oscillations of the Single Helical States in Reversed Field Pinch plasmas

    Science.gov (United States)

    Paccagnella, Roberto

    2013-10-01

    In this work a model that could explain the experimentally observed quasi periodical oscillations in electron temperature and perturbed magnetic field in a Reversed Field Pinch is discussed. An ohmically heated plasma in which an interplay between thermal conduction and heat transport, on one side, and the magneto-hydro-dynamical stability, on the other side, is studied. It is shown that, by making some simple and physically reasonable assumptions, a set of equations can be obtained showing a variety of periodical or quasi periodical oscillations for the relevant dynamical variables.

  7. Using Bourdieu in Critical Mediatization Research: Communicational Doxa and Osmotic Pressures in the Field of UN Organizations

    Directory of Open Access Journals (Sweden)

    André Jansson

    2015-05-01

    Full Text Available This article develops a Bourdieusian approach to mediatization. It is argued that the Bourdieusian theories of doxa and fields can make valuable contributions to a critical perspective on mediatization, one that moves beyond the divides between institutionalist, social-constructivist and materialist understandings (e.g., Bourdieu, 1972/1977. Mediatization is here seen as the historically growing dependence on media technologies and institutions within diverse social fields and settings. In order to establish the link between mediatization and Bourdieu’s theories (ibid., the article introduces the concept of communicational doxa, which refers to the taken for granted communicational conventions and demands that regulate the inclusion of membership within a particular field. The article also shows how communicational doxa can be applied as an analytical concept. Findings from qualitative fieldwork carried out among highly mobile and skilled professionals within the field of UN organizations in Geneva, show how the autonomy of social agents is negotiated in relation to an increasingly mediatized communicational doxa.

  8. Magnetic field effects on the charge-density-wave and superconducting states in pressurized {alpha}-(BEDT-TTF){sub 2}KHg(SCN){sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Kartsovnik, M.V., E-mail: mark.kartsovnik@wmi.badw.de [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, 85748 Garching (Germany); Biberacher, W.; Andres, D.; Jakob, S.; Kunz, M.; Neumaier, K. [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, 85748 Garching (Germany); Mueller, H. [European Synchrotron Radiation Facility, 38043 Grenoble (France); Kushch, N.D. [Institute of Problems of Chemical Physics, 142432 Chernogolovka (Russian Federation)

    2012-06-01

    Coupling of a magnetic field to the orbital and spin degrees of freedom of charge carriers is well known to cause suppression of superconductivity. While the orbital pair-breaking generally dominates in conventional superconductors, the Pauli paramagnetic effect may become important in some heavy fermion compounds or strongly anisotropic materials such as high-T{sub c} or organic superconductors. The same two mechanisms are predicted to be operative also in the case of charge-density-wave (CDW) ordering. However, now they lead to opposite effects: the paramagnetic coupling weakens the CDW interaction whereas the orbital coupling enhances it in a system with an imperfectly nested Fermi surface. Here we report on the experimental evidence of both kinds of magnetic field effects on the CDW and superconducting instabilities in the layered organic metal {alpha}-(BEDT-TTF){sub 2}KHg(SCN){sub 4} under quasihydrostatic pressure.

  9. Magnetic field effects on the charge-density-wave and superconducting states in pressurized α-(BEDT-TTF)2KHg(SCN)4

    Science.gov (United States)

    Kartsovnik, M. V.; Biberacher, W.; Andres, D.; Jakob, S.; Kunz, M.; Neumaier, K.; Müller, H.; Kushch, N. D.

    2012-06-01

    Coupling of a magnetic field to the orbital and spin degrees of freedom of charge carriers is well known to cause suppression of superconductivity. While the orbital pair-breaking generally dominates in conventional superconductors, the Pauli paramagnetic effect may become important in some heavy fermion compounds or strongly anisotropic materials such as high-Tc or organic superconductors. The same two mechanisms are predicted to be operative also in the case of charge-density-wave (CDW) ordering. However, now they lead to opposite effects: the paramagnetic coupling weakens the CDW interaction whereas the orbital coupling enhances it in a system with an imperfectly nested Fermi surface. Here we report on the experimental evidence of both kinds of magnetic field effects on the CDW and superconducting instabilities in the layered organic metal α-(BEDT-TTF)2KHg(SCN)4 under quasihydrostatic pressure.

  10. Acoustics. Noise emitted by machinery and equipment. Measurement of emission sound pressure levels at a work station and at other specified positions. Engineering method in an essentially free field over a reflecting plane

    CERN Document Server

    British Standards Institution. London

    1996-01-01

    Acoustics. Noise emitted by machinery and equipment. Measurement of emission sound pressure levels at a work station and at other specified positions. Engineering method in an essentially free field over a reflecting plane

  11. Prediction and Characteristic Analysis of Ground Surface Settlement Caused by Construction of Twin-tube Tunnels%盾构法双管隧道施工引起的地表沉降预测及特征分析

    Institute of Scientific and Technical Information of China (English)

    晏莉

    2015-01-01

    盾构法双管隧道施工产生的地表沉降预测方法按照不同的分析原理,可归纳为半经验分析法、理论分析法和数值分析法。分析了各种方法的优缺点,搜集国内外41条双管盾构隧道工程的地表沉降实测曲线,通过对曲线分布形态及其成因的分析以及地表最大沉降值数据的归纳整理,总结了双管隧道施工地表沉降分布的3大特点,即:1)地表沉降曲线主要呈现“单峰”和“双峰”2种形态,双管隧道间距及埋深是决定曲线形态的重要因素;2)影响地表沉降曲线形态的因素主要为地质和环境因素以及施工因素;3)地表最大沉降值与隧道埋深、双管隧道的间距、地层条件以及采用的盾构方法等均有密切的联系。%Based on the different analysis principles, the methods used to predict the ground surface settlement caused by the construction of twin-tube tunnels are classified into semi-empirical analysis method, theoretical analysis method and numerical analysis method, whose advantages and disadvantages are analyzed. Curves of measured ground surface settlement caused by the construction of 41 twin-tube tunnels at home and abroad are collected. Through the analysis on the shape and causes of the curves as well as the analysis on the data of the maximum ground surface settlement, the following three main characteristics are summarized for the distribution curves of the ground surface settlement caused by the shield construction of twin-tube tunnels:1 ) The ground surface settlement curves mainly present “unimodal” and“bimodal” forms. Both the distance between twin tubes and the tunnel depth have great influence on the curve forms;2 ) The main factors that have influence on the ground surface settlement distribution curves include the geological fac-tors , the environmental factors and the construction factors;3 ) The maximum ground surface settlement is closely related to the tunnel

  12. Optimation Pressure Loss to Oil Production System with Electrical Submersible Pump (ESP) at the Well A SW Field Bojonegoro, East Java

    Science.gov (United States)

    Ilmah, A. M.; Hendrajaya, L.

    2017-07-01

    Study about oil and gas well A and SW fields have been conducted in Bojonegoro area, East Java Province. From the research, it is known that one of the constrain in oil and gas production process is a pressure drop, so that is necessary to set Electrical Submersible Pump (ESP) as an artificial lift pump at low pressure wells. It is needed to analyze the production well pressure as an effort to optimize the fluid production. It is in describe to relations between IPR (Inflow Performance Relationship ) curve with TPR (Tubing Performance Relationship), are getting down point cut TPR curve with IPR curve, fluid rate its optimal, so need tubing’s diameter variation and the number of stage pump ESP variation to can the most optimal fluid rate. Produced that to tubing variation are 2,441 ID is 876,729 bpd, 2,991 is 961,197 bpd, 3,476 id is 996, 26 Bpd, while on the number of stage pump esp variation The most high is stage 400 with fluid rate 961,197 by comparison stage 338 it has value fluid rate 921,165 bpd, stage 200 it has fluid rate 827,889 bpd, and stage 169 has fluid rate 774,646 bpd. Of some variation tubing and stage pumps that has the most influence to fluid rate optimalize is the change number of stage pump.

  13. Study of magnetic, structural and magnetocaloric properties of La0.6Pr0.4Mn2Si2 under high pressures and magnetic field

    Science.gov (United States)

    Kaštil, J.; Arnold, Z.; Isnard, O.; Skourski, Y.; Kamarád, J.; Itié, J. P.

    2017-02-01

    The structural, magnetic and magnetocaloric properties of La0.6Pr0.4Mn2Si2 compound were measured in wide range of temperature, magnetic field and hydrostatic pressure. The structural study up to 10 GPa confirmed the existence of critical Mn-Mn distance 0.2883 nm for the ferromagnetic to antiferromagnetic transition at room temperature. The results demonstrated the crucial role of the volume in the suppression of the ferromagnetic phase above the transition temperature T1=168 K under pressure. The huge pressure shift of the transition temperature T1, dT1/dp=230 K/GPa, was observed. Based on our magnetization measurement the low temperature transition at T2=30 K is connected with reorientation of Mn moment and the rare-earth sublattice is not ordered in this case. The direct magnetocaloric measurement showed moderate values of the adiabatic temperature change connected with the magnetic transition at Tc and T1 and confirmed the first order character of the transition at T1 and second order character of the transition at Tc.

  14. Phase Diagram Of UGe2: The Magnetic Transition within the Ferromagnetic Phase and the Superconducting Transition; the Effect of Magnetic Field on the Ambient-Pressure Ferromagnetic Phase

    Science.gov (United States)

    Phillips, N. E.; Bouquet, F.; Fisher, R. A.; Hardy, F.; Oeschler, N.; Lashley, J. C.; Flouquet, J.; Huxley, A.

    2007-03-01

    Superconductivity in UGe2 occurs near 1.2 GPa at the 0-K termination of the phase boundary (Tx, Px) of a magnetic transition that occurs within the ferromagnetic phase. Ambient-pressure specific-heat measurements show a hysteretic transition at Tx(0) ˜ 22 K, reminiscent of the CDW/SDW transition in α-U, and consistent with the suggestion that the transition in UGe2 is also a CDW/SDW transition. The magnetic field dependence of the specific heat, at ambient pressure, demonstrates the presence of structure in the electron density of states and an unusual nature of the ferromagnetic ordering at the Curie temperature. Specific-heat measurements to 1.8 GPa give an estimate of the latent heat of the transition and determine the phase boundary for 1 <= T <= 11 K. Contrary to expectations, the onset temperature of the superconducting transition is independent of pressure in the region in which it was observed, 1.08 <= P <= 1.35 GPa.

  15. 汶川地震强震动地面倾斜研究%Study of ground surface tilts from strong motion records of the Wenchuan earthquake

    Institute of Scientific and Technical Information of China (English)

    彭小波; 李小军

    2012-01-01

    根据三分量强震动传感器水平摆和竖向摆对倾斜的动力响应差异,利用谱比法计算出汶川Ms8.0地震中近断层强震动的断层法线方向和平行方向的同震地面倾斜.结果表明,本次地震中强震动观测台处地面倾斜一般小于1°,影响频段主要在0.1 Hz以下,发生较大倾斜的台站主要在距地表破裂迹线30 km以内,在100 km之外或水平向加速度幅值均方根在200 cm/s2以下时很少发生0.01°以上的同震地面倾斜.总体上看,上盘区域的倾斜值普遍小于下盘区域,法线方向倾斜值一般大于平行线方向倾斜值.位于前山断裂与中央断裂之间区域的绵竹清平台谱比较低但平缓且频带较宽,可能反应了该区域的运动特殊性,而汶川卧龙台则显示了上盘边缘区域地面倾斜较大.逆冲段与走滑段台站倾斜对比显示,地面倾斜可能受局部场地条件影响较大.%Based on the difference of dynamic response to tilts between horizontal pendulums and vertical pendulum, spectral ratio method was applied to estimate the coseismic surface tilts deduced from strong motion records of the Wen-chuan earthquake. The result shows that the ground surface tilts are generally less than 1 degree and mainly appears within 30 km to fault rupture surface traces, while rarely discovered in the area outside 100 km or root-mean-squared horizontal peak accelerations are less than 200 cm/s2. The frequency band influenced by tilts is less than 0. 1 Hz. In general, tilts in hanging wall is greater than that in footwall in near fault areas, and tilts in normal direction of fault is less than those in parallel direction. The spectral ratio of Qingping station located between central fault and front mount fault is relatively low and stable, which may imply ae special movement feature of the area. The tilts of Wolong station may be controlled by deformation transition from the hanging wall to laterally stationary area. Comparison of tilts

  16. Fundamental study on filter effect of confronting divergent magnetic fields applied to low-pressure inductively coupled plasmas

    Science.gov (United States)

    Sugawara, Hirotake; Ogino, So

    2016-07-01

    The electron motion under confronting divergent magnetic fields (CDMFs) applied to inductively coupled plasmas was simulated using a Monte Carlo method. The CDMFs induced by two coaxial dc coils confined electrons in one side of the separatrix of the CDMFs. However, electrons diffused across the separatrix mainly in two ways. One was the displacement of their gyrocenters due to scattering near the outer part of the separatrix. This process tended to occur for high-energy electrons with correspondingly large gyroradii. The other was passage through the weak magnetic field around the center. This process was allowed for low-energy electrons. The position-dependent selectivity about the electron energy was pointed out as a seed property for applications of the separatrix as a magnetic filter or shutter. The mechanism by which the functions of the separatrix emerge was explained from a viewpoint of electron motion under the CDMFs.

  17. Field effect surface passivation of SiO{sub 2}/Si interfaces by heat treatment with high-pressure H{sub 2}O vapor

    Energy Technology Data Exchange (ETDEWEB)

    Sakamoto, K.; Asada, K.; Sameshima, T. [Tokyo University of Agriculture and Technology, 2-24-16 Nakamachi, Koganei, 184-8588 Tokyo (Japan)

    2001-01-01

    We investigated a simple field effect passivation of the silicon surfaces using the high-pressure H{sub 2}O vapor heating. Heat treatment with 2.1x10{sup 6}Pa H{sub 2}O vapor at 260C for 3h reduced the surface recombination velocity from 405cm/s (before the heat treatment) to 38cm/s for the thermally evaporated SiO{sub x} film/Si. Additional deposition of 140nm-SiO{sub x} films (x<2) with a high density of fixed positive charges on the SiO{sub 2}/Si samples further decreased the surface recombination velocity to 22cm/s. We also demonstrated the field effect passivation for n-type silicon wafer coated with thermally grown SiO{sub 2}. Additional deposition of 210nm SiO{sub x} films on both the front and rear surfaces increased the effective lifetime from 1.4 to 4.6ms. Combination of thermal evaporation of SiO{sub x} film and the heat treatment with high-pressure H{sub 2}O vapor is effective for low-temperature passivation of the silicon surface.

  18. Spectral Analysis of Pore Pressure Data Recorded from the 2010 Sierra EL Mayor (baja California) Earthquake at the NEES@UCSB Wildlife Field Site

    Science.gov (United States)

    Seale, S. H.; Lavallee, D.; Steidl, J. H.; Ratzesberger, H.; Hegarty, P.

    2010-12-01

    On 4 April 2010, the M7.2 Sierra el Mayor event occurred in Baja California, Mexico. The NEES@UCSB Wildlife field site in the Imperial Basin is located 110 km NNW of the hypocenter. The event was recorded on all channels: by three-component strong-motion accelerometers at the surface and in boreholes at various depths and by pore pressure transducers located in a saturated, liquefiable layer. We have computed the spectra of the pore pressure response in the frequency domain for signals recorded at different depths. At each depth, the spectrum is attenuated as a power law with a sharp discontinuity at a frequency close to 1 Hz. We report the value of the exponents that characterize the power-law behavior of these spectra. We also computed cross-spectral analysis of the pore pressure records from different depths. The functional behaviors of the curves of the cross-spectra are similar to that of the original spectra. For comparison, we present the spectrum of each component of the ground motion recorded at a nearby accelerometer. Partially due to the late arrival of the surface waves, the frequency content of the recorded pore pressure signal is a function of time. To gain a better understanding of the time-dependence of the frequency content, we performed spectral analysis of the signal in a moving window and wavelet transforms of the full signals. The spectral analysis suggests that, except for high frequencies, the curves exhibit a complex behavior as a function of the window position. We interpret and discuss the consequences of the estimated spectra, the cross-spectra, and the wavelet transforms.

  19. A linear-field plasma jet for generating a brush-shaped laminar plume at atmospheric pressure

    Science.gov (United States)

    Li, Xuechen; Li, Jiyuan; Chu, Jingdi; Zhang, Panpan; Jia, Pengying

    2016-06-01

    A linear-field plasma jet composed of line-to-plate electrodes is used to generate a large-scale brush-shaped plasma plume with flowing argon used as working gas. Through electrical measurement and fast photography, it is found that the plasma plume bridges the two electrodes for the discharge in the positive voltage half-cycle, which behaves like fast moving plasma bullets directed from the anode to the cathode. Compared with the positive discharge, the negative discharge only develops inside the nozzle and propagates much slower. Results also indicate that the gas temperature of the plume is close to room temperature, which is promising for biomedical application.

  20. Pinning and trapped field in MgB2- and MT-YBaCuO bulk superconductors manufactured under pressure

    Science.gov (United States)

    Prikhna, T.; Eisterer, M.; Chaud, X.; Weber, H. W.; Habisreuther, T.; Moshchil, V.; Kozyrev, A.; Shapovalov, A.; Gawalek, W.; Wu, M.; Litzkendorf, D.; Goldacker, W.; Sokolovsky, V.; Shaternik, V.; Rabier, J.; Joulain, A.; Grechnev, G.; Boutko, V.; Gusev, A.; Shaternik, A.; Barvitskiy, P.

    2016-03-01

    The relevant pinning centers of Abrikosov vortices in MgB2-based materials are oxygen-enriched Mg-B-O inclusions or nanolayers and inclusions of MgBx (x>4) phases. The high critical current densities, j c, of 106 and 103A/cm2 at 1 and 8.5 T, respectively, at 20 K can be achieved in polycrystalline materials (prepared at 2 GPa) containing a large amount of admixed oxygen. Besides, oxygen can be incorporated into the MgB2 structure in small amounts (MgB1.5O0.5), which is supported by Auger studies and calculations of the DOS and the binding energy. The j c of melt textured YBa2Cu3O7-δ (or Y123)-based superconductors (MT-YBaCuO) depends not only on the perfectness of texture and the amount of oxygen in the Y123 structure, but also on the density of twins and micro-cracks formed during the oxygenation (due to shrinking of the c-lattice parameter). The density of twins and microcracks increases with the reduction of the distance between Y2BaCuO5 (Y211) inclusions in Y123. At 77 K jc=8·104 A/cm2 in self-field and jc=103 A/cm2 at 10 T were found in materials oxygenated at 16 MPa for 3 days with a density of twins of 22–35 per µm (thickness of the lamellae: 45-30 nm) and a density of micro-cracks of 200–280 per mm. Pinning can occur at the points of intersection between the Y123 twin planes and the Y211 inclusions. MTYBaCuO at 77 K can trap 1.4 T (38×38×17 mm, oxygenated at 0.1 MPa for 20 days) and 0.8 T (16 mm in diameter and 10 mm thick with 0.45 mm holes oxygenated at 10 MPa for 53 h). The sensitivity of MgB2 to magnetic field variations (flux jumps) complicates estimates of the trapped field. At 20 K 1.8 T was found for a block of 30 mm in diameter and a thickness of 7.5 mm and 1.5 T (if the magnetic field was increased at a rate of 0.1 T) for a ring with dimensions 24×18 mm and a thickness of 8 mm.

  1. Modeling of a tilted pressure-tuned field-widened Michelson interferometer for application in high spectral resolution lidar

    Science.gov (United States)

    Liu, Dong; Hostetler, Chris; Miller, Ian; Cook, Anthony; Hair, Jonathan

    2011-10-01

    High spectral resolution lidars (HSRLs) designed for aerosol and cloud remote sensing are increasingly being deployed on aircraft and called for on future space-based missions. The HSRL technique relies on spectral discrimination of the atmospheric backscatter signals to enable independent, unambiguous retrieval of aerosol extinction and backscatter. A compact, monolithic field-widened Michelson interferometer is being developed as the spectral discrimination filter for an HSRL system at NASA Langley Research Center. The Michelson interferometer consists of a cubic beam splitter, a solid glass arm, and an air arm. The spacer that connects the air arm mirror to the main part of the interferometer is designed to optimize thermal compensation such that the frequency of maximum interference can be tuned with great precision to the transmitted laser wavelength. In this paper, a comprehensive radiometric model for the field-widened Michelson interferometeric spectral filter is presented. The model incorporates the angular distribution and finite cross sectional area of the light source, reflectance of all surfaces, loss of absorption, and lack of parallelism between the airarm and solid arm, etc. The model can be used to assess the performance of the interferometer and thus it is a useful tool to evaluate performance budgets and to set optical specifications for new designs of the same basic interferometer type.

  2. Pressure while drilling system development and field test%随钻压力测量系统的研制与现场试验

    Institute of Scientific and Technical Information of China (English)

    张涛; 柳贡慧; 李军; 李立昌; 王帅; 谭天宇

    2012-01-01

    The balance relationship between bottom hole annulus pressure and formation pressure is a key factor to affect the drilling operation safety. Because of the complex and various situation underground, there is a big error between the actual bottomhole pressure and calculated one. The paper introduced a PWD system which can measure the parameters of weight on bit (WOB), torque, annulus pressure, annulus temperature, pressure inside the drill string, etc., and transmit the measurement data to the ground in real time. With the real time measurement data, the wellbore hydraulic model can be corrected in real time, and the underground situation can be interpreted in real time, what is more, the drilling accident can be predicted in real time. The field test proves the accuracy and reliability of the measurement system. Compared with the storage PWD system, this measurement system is more accurate, and has the function of transmitting the measured data in real time, so it can offer powerful technical support for drilling operation.%井底环空压力与地层压力的平衡关系是影响钻井作业安全的重要因素.由于井下工况复杂多变,而目前通过水力模型理论计算所得的井底压力与实际压力值存在较大的误差.文中介绍了一种可以测量近钻头处钻压、扭矩、环空压力、环空温度及钻柱内压力等参数并将测量数据实时传输至地面的随钻压力测量系统(PWD).依靠PWD的实时测量数据,可以实时修正井筒水力模型,解释井底工况,预测钻井事故.现场试验证明,该测量系统测量参数准确、工作稳定可靠.通过与存储式PWD测量数值对比,该测量系统有较高的测量精度,具有实时传输测量数据功能,可为钻井作业提供有力的技术支持.

  3. OLM interneurons are transiently recruited into field gamma oscillations evoked by brief kainate pressure ejections onto area CA1 in mice hippocampal slices.

    Science.gov (United States)

    Kipiani, E

    2009-02-01

    Oscillations (30-100 Hz) are correlated with the cognitive functions of the brain. In the hippocampus interactions between perisomatic and trilaminar interneurons with pyramidal cells are thought to underlie generation of field gamma oscillations. In area CA3 OLM interneurons receive synaptic input in gamma range but generate action potential (AP) output in theta band and are involved in theta oscillations synchronized along the longitudinal axis of the hippocampus. In slice preparations of CA3 area the spike timing of OLM cells could be modulated by carbachole induced gamma oscillations, although their firing rates are limited to theta frequency. Normally, OLM interneurons are somatostatin positive cells. In this study we tested whether parvalbumin (PV) containing OLM interneurons in area CA1 limit AP output during kainate pressure ejection also to theta frequency. We used focal short applications of kainate in area CA1 to induce filed gamma oscillations with an average frequency of about 44.7+/-4.4 Hz. The duration of field gamma was on average 8.9+/-3.5 s. During such oscillations CA1 PV positive OLM interneurons of mice hippocampus received excitatory synaptic input at gamma frequency. Moreover, their AP output was in gamma range as well. Thus, we show that beside the somatostatin containing OLM interneurons, which generate theta rhythm there are PV containing OLM cells, which could synchronize the distal dendrites of CA1 pyramidal cells to the field gamma oscillations.

  4. X-ray emission from a nanosecond-pulse discharge in an inhomogeneous electric field at atmospheric pressure

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Cheng; Shao Tao; Ren Chengyan; Zhang Dongdong [Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Key Laboratory of Power Electronics and Electric Drive, Chinese Academy of Sciences, Beijing 100190 (China); Tarasenko, Victor; Kostyrya, Igor D. [Institute of High Current Electronics, Russian Academy of Science, Tomsk 634055 (Russian Federation); Ma Hao [Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Yan Ping [Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Key Laboratory of Power Electronics and Electric Drive, Chinese Academy of Sciences, Beijing 100190 (China); State Key Laboratory of Electrical Insulation and Power Equipment, Xi' an Jiaotong University, Xi' an 710049 (China)

    2012-12-15

    This paper describes experimental studies of the dependence of the X-ray intensity on the anode material in nanosecond high-voltage discharges. The discharges were generated by two nanosecond-pulse generators in atmospheric air with a highly inhomogeneous electric field by a tube-plate gap. The output pulse of the first generator (repetitive pulse generator) has a rise time of about 15 ns and a full width at half maximum of 30-40 ns. The output of the second generator (single pulse generator) has a rise time of about 0.3 ns and a full width at half maximum of 1 ns. The electrical characteristics and the X-ray emission of nanosecond-pulse discharge in atmospheric air are studied by the measurement of voltage-current waveforms, discharge images, X-ray count and dose. Our experimental results showed that the anode material rarely affects electrical characteristics, but it can significantly affect the X-ray density. Comparing the density of X-rays, it was shown that the highest x-rays density occurred in the diffuse discharge in repetitive pulse mode, then the spark discharge with a small air gap, and then the corona discharge with a large air gap, in which the X-ray density was the lowest. Therefore, it could be confirmed that the bremsstrahlung at the anode contributes to the X-ray emission from nanosecond-pulse discharges.

  5. The influence of NDT-Bobath and PNF methods on the field support and total path length measure foot pressure (COP) in patients after stroke.

    Science.gov (United States)

    Krukowska, Jolanta; Bugajski, Marcin; Sienkiewicz, Monika; Czernicki, Jan

    In stroke patients, the NDT - (Bobath - Neurodevelopmental Treatment) and PNF (Proprioceptive Neuromuscular Facilitation) methods are used to achieve the main objective of rehabilitation, which aims at the restoration of maximum patient independence in the shortest possible period of time (especially the balance of the body). The aim of the study is to evaluate the effect of the NDT-Bobath and PNF methods on the field support and total path length measure foot pressure (COP) in patients after stroke. The study included 72 patients aged from 20 to 69 years after ischemic stroke with Hemiparesis. The patients were divided into 4 groups by a simple randomization. The criteria for this division were: the body side (right or left) affected by paresis and the applied rehabilitation methods. All the patients were applied the recommended kinesitherapeutic method (randomized), 35 therapy sessions, every day for a period of six weeks. Before initiation of therapy and after 6 weeks was measured the total area of the support and path length (COP (Center Of Pressure) measure foot pressure) using stabilometer platform - alpha. The results were statistically analyzed. After treatment studied traits decreased in all groups. The greatest improvement was obtained in groups with NDT-Bobath therapy. NDT-Bobath method for improving the balance of the body is a more effective method of treatment in comparison with of the PNF method. In stroke patients, the effectiveness of NDT-Bobath method does not depend on hand paresis. Copyright © 2016 Polish Neurological Society. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

  6. Results and Analysis of a L2F Flow Field Investigation within a High-Speed High-Pressure Centrifugal Compressor

    Institute of Scientific and Technical Information of China (English)

    1997-01-01

    The paper describes experimental results obtained using a laser two-focus anemometry technique in a high-speed,high-pressure ratio unshrouded centrifugal compressor.Measurements in such a small impeller are extremely difficult as the flow is restricted to marrow passages and as the temperature rise is very high.Even if the working principle of laser anemometry is well documented in literature,some specialities of our LA system are discussed.A description and an analysis of the inlet flow field.based on integral methods,are propsed.Some passage velocity contours are presented.Whereas a potential flow structure exists up to the high meridional curvature region,the throughflow patterm is largely distorted in the radial part of the impeller.Noticeable differences in flow pattern between both channels are found,particularyly through the low momentum fluid zone.A qualitative study of the vortical mechanisms ascribes them to the tip clearance effects.

  7. A classification of the sea level pressure daily fields in southern South America: an application to daily rainfall in the Pampas region.

    Science.gov (United States)

    Penalba, Olga; Bettolli, Maria Laura

    2010-05-01

    The Pampas covers Argentina's most productive agricultural land, extending more than 1600 km in the heartland of the country. The impact of climate adversities on agricultural activities makes it necessary to determine to what extent climate spatial and temporal variability is responsible for crop yields and to generate elements to monitor, estimate impacts and design an alert system. Local atmospheric conditions depend, among other factors, on the major scale fields. Consequently, an objective classification of daily circulation fields in the South of South America is proposed using a long database. Daily rainfalls within the Argentine Humid Pampas are also investigated in connection to the weather type categories. Daily mean sea level pressure (SLP) fields corresponding to the NCEP_Reanalysis 2 data provided by the NCEP-NCAR were used as representative of atmospheric circulation at low levels which is of great importance in determining moisture advection in the region. The period of study was 1979-1999. The chosen domain extends from 15°S to 60°S and from 40°W to 90° W on a 2.5° latitude-longitude grid. This domain extends over the Pacific and the Atlantic Oceans and the Andes Mountains, all of which have a significant influence on the atmospheric circulation over South America. The analyzed seasons correspond to summer (December-January- February) and winter (June-July-August). Daily rainfall series located in the core region for growing different crops in the Argentine Humid Pampas were also used. These series were provided by the Argentine National Meteorological Service. Cluster analysis was performed coupled with Principal Component Analysis (PCA) to determine the atmospheric circulation patterns. PCA was used as a synthesis method and the cluster analysis was carried out in the subspace given by the leading unrotated principal components. The ‘k-means' partitioning method with Euclidean distance was used. The choice of the optimal number of clusters

  8. Effects of assisted magnetic field to an atmospheric-pressure plasma jet on radical generation at the plasma-surface interface and bactericidal function

    Science.gov (United States)

    Liu, Chih-Tung; Kumakura, Takumi; Ishikawa, Kenji; Hashizume, Hiroshi; Takeda, Keigo; Ito, Masafumi; Hori, Masaru; Wu, Jong-Shinn

    2016-12-01

    A configuration of magnetic-assisted-plasma (MAP) on helium-based atmospheric-pressure plasma jet (APPJ) with an axial magnetic-field of 0.587 T is proposed, which provides good ability for killing bacteria Escherichia coli on the agar surface. Optically, we confirmed that the MAP increased approximately 2.4 times in the electron density estimated by the Stark broadening of H β line emission, and approximately 1.5 times enhancement of atomic oxygen concentration measured by vacuum ultraviolet absorption spectroscopy (VUVAS). Moreover, the generation of hydroxyl radical in the water increased 1.5 times, confirmed by the spin-trapping electron spin-resonance technique. In addition, the bactericidal experiments demonstrated 2.4 times higher for E. coli by the MAP treatment. The MAP configuration is proposed to be highly useful for future bio-medical applications by enhancing the radical generation at the plasma/substrate interface region.

  9. Field test of low-pressure turbine blading with improved resistance against corrosion fatigue; Faeltprovning av laagtrycksturbinskovlar med foerbaettrad haerdighet mot korrosionsutmattning

    Energy Technology Data Exchange (ETDEWEB)

    Tavast, Jueri [Alstom Power Sweden AB, Finspong (Sweden)

    2003-07-01

    Corrosion fatigue of turbine blades in low-pressure turbines is one of the most common reasons for reduced availability and reliability in fossil fueled as well as in nuclear steam turbine plants. The problem is almost exclusively localized to the area where the first condensation takes place. There is therefore a need for materials with improved resistance towards corrosion fatigue for blades in stages in the transition zone between dry and wet steam. The phase hardening stainless steel 15/5 PH is such an alternative material. This material has shown a significantly better resistance towards corrosion and corrosion fatigue in laboratory tests. The lack of field experience of this material in real plants has, however, made it difficult to introduce this relatively new and untried material. Corrosion fatigue has caused problems in the some of the nuclear units in Forsmark. Forsmark 2 was therefore regarded as a suitable plant for a field test. The result of the field test is applicable to conventional as well as to nuclear units. A total of 10 blades of 15/5 PH were installed to replace blades of conventional blade material in a stage with a ar and 40 previous history of corrosion fatigue. The field test was interrupted after 5 years and 40,000 hours of operation. The main objective of the field test was to demonstrate that blades of 15/5 PH could be successfully machined, tested, installed and of course also used in a real plant. The field test also enabled a comparison of the corrosion resistance of the two alloys. It should be underlined that demonstration of the improved resistance towards corrosion fatigue has not been an objective during this field test as this has already been evidenced by various laboratory investigations. The properties of the parent material as well as of the finished blades were controlled and documented as carefully as possible before the field test to enable evaluation of the field test. The condition of the 10 blades of 15/5 PH

  10. Pressure and velocity cross-spectrum of normal modes in low-frequency acoustic vector field of shallow water and its application

    Institute of Scientific and Technical Information of China (English)

    Yun Yu; Qing Ling,; Jiang Xu

    2015-01-01

    The pressure and horizontal particle velocity combined descriptions in the very low frequency acoustic field of shal ow wa-ter integrated with the concept of effective depth of Pekeris wave-guide is proposed, especial y the active component of the pressure and horizontal particle velocity cross-spectrum, also cal ed ho-rizontal complex cross acoustic intensity, when only two normal modes are trapped in the waveguide. Both the approximate theo-retic analysis and the numerical results show that the sign of the horizontal complex cross acoustic intensity active component is independent of the range when vertical y deployed receiving dual sensors are placed in appropriate depths, the sum of which is equal to the waveguide effective depth, so it can be used to tel whether the sound source is near the surface or underwater;while the range rate is expected to be measured by utilizing the sign distribution characteristic of the reactive component. The further robustness analysis of the depth classification algorithm shows that the existence of shear waves in semi infinite basement and the change of acoustic velocity profiles have few effects on the application of this method, and the seabed attenuation wil limit the detection range, but the algorithm stil has a good robustness in the valid detection range.

  11. Remote field Eddy Current Technique Development for Gap Measurement of Neighboring Tubes of Nuclear Fuel Channel in Pressurized Heavy Water Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Jung, H. K.; Lee, D. H.; Lee, Y. S.; Huh, H.; Cheong, Y. M. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2004-04-15

    Liquid Injection Nozzle(LIN) tube and Calandria tube(CT) in pressurized Heavy Water Reactor (PHWR) are cross-aligned horizontally. These neighboring tubes can contact each other due to the sag of the calandria tube resulting from the irradiation creep and thermal creep, and fuel load, etc. In order to judge the contact which might be the safety concern, the remote field eddy current (RFEC) technology is applied for the gap measurement in this paper. LIN can be detected by inserting the RFEC probe into pressure tube (PT) at the crossing point directly. To obtain the optimal conditions of the RFEC inspection, the sensitivity, penetration and noise signals are considered simultaneously. The optimal frequency and coil spacing are 1kHz and 200mm respectively. Possible noises during LIN signal acquisition are caused by lift-off, PT thickness variation, and gap variation between PT and CT. The simulated noise signals were investigated by the Volume Integral Method(VIM). Signal analysis on the voltage plane describes the amplitude and shape of LIN and possible defects at several frequencies. All the RFEC measurements in the laboratory were done in variance with the CT/LIN gap and showed the relationship between the LIN gap and the signal parameters by analyzing the voltage plane signals

  12. Second-Harmonic Generation in Vertically Coupled InAs/GaAs Quantum Dots with a Gaussian Potential Distribution: Combined Effects of Electromagnetic Fields, Pressure, and Temperature

    Science.gov (United States)

    Ben Mahrsia, R.; Choubani, M.; Bouzaiene, L.; Maaref, H.

    2015-08-01

    Simulation of quantum dots (QD) is usually performed on the basis of abrupt changes between neighboring materials. In practice, it is not possible to construct such QD because in a real structure the interface between two adjacent materials is not a step. In the work discussed in this paper, vertically coupled InAs/GaAs quantum dots (VCQD) with a non-abrupt change between two neighboring materials are considered. A potential function in the form of a Gaussian distribution was used to show this effect. We also focused on studying the effect of structure, applied electric ( F) and magnetic ( B) fields, pressure ( P), and temperature ( T) on second-harmonic generation (SHG). The analytical expression for SHG was investigated theoretically by use of the density matrix approach, the effective mass, and the finite-difference method (FDM). It was found that the major resonant peak value of SHG is a non-monotonic function of the barrier width ( L B). Moreover, the major resonant peak of SHG is blue-shifted (red-shifted) and its magnitude increases (decreases) monotonically with increasing temperature (pressure). The results obtained also show that the magnitude and position of the resonant peaks of SHG are affected by changes in external conditions, for example applied electric and magnetic fields, structural dimensions of the coupled QD system, and relaxation time ( T 0). Calculations also show that SHG in a VCQD structure with a non-abrupt potential change can be controlled and optimized by appropriate choice of structural dimensions and the external conditions mentioned above.

  13. Influence of sustained deworming pressure on the anthelmintic resistance status in strongyles of sheep under field conditions.

    Science.gov (United States)

    Vijayasarathi, M K; Sreekumar, C; Venkataramanan, R; Raman, M

    2016-10-01

    Anthelmintic resistance (AR) status in Madras Red sheep from selected field flocks of a government funded scheme, covered by regular, sustained anthelmintic treatment for more than 10 years was determined. Parameters such as fecal egg count reduction test (FECRT), larval paralysis assay (LPA), and allele-specific-PCR (AS-PCR) were used to test the efficacy of fenbendazole, tetramisole, and ivermectin at recommended doses, in two seasons. Sheep belonging to non-beneficiary farmers were used as controls. Mean FECRT values of beneficiary group during winter and summer seasons were 77.77 and 76.04, 93.65 and 92.12, and 95.37 and 98.06 %, respectively, for fenbendazole, tetramisole, and ivermectin. In the non-beneficiary groups, the corresponding values were 74.82 and 81.09 %, 96.05 and 97.40 %, and 97.26 and 98.23 %, respectively. The results revealed resistance to fenbendazole, suspect resistance to tetramisole and susceptibility to ivermectin in beneficiary flock. In non-beneficiary flock, while resistance was noticed against fenbendazole, both tetramisole and ivermectin were effective. FECR values were found to be significantly different between beneficiary and non-beneficiary groups against tetramisole. The results of LPA confirmed this finding, as 50 % of the Haemonchus contortus larvae were paralyzed at the concentration of 0.0156 μg/ml in the beneficiary group, while those of non-beneficiary groups required lower concentrations of 0.0078 μg/ml. AS-PCR revealed the predominance of heterozygous susceptible population of H. contortus in the beneficiary group. In this study, resistance to fenbendazole was confirmed in both the beneficiary and non-beneficiary groups and this could be attributed to frequent use of benzimidazoles as seen from the deworming records. Emergence of tetramisole resistance was detected in the beneficiary group, where the drug was used continuously for 4 years. Ivermectin was found to be effective in all the flocks. It is

  14. Managed pressure drilling from floaters: feasibility studies for applying managed pressure drilling from a floater on the Skarv/Idun field on the Norwegian Continental Shelf by PGNiG Norway AS

    OpenAIRE

    Chrzanowski, Wojciech Stanislaw

    2011-01-01

    Managed Pressure Drilling (MPD) is a relatively young technology that has improved some old ideas of Underbalanced Drilling (UBD). According to the IADC, MPD is an “adaptive process used to precisely control the annular pressure profile throughout the wellbore. The goal is to ascertain the downhole pressure environment limits and to manage the annular pressure profile accordingly”. In other words the main aim of MPD is to avoid continuous influx of formation fluids to the surfa...

  15. Relationship Between Far Field Stresses, Fluid Flow and High-Pressure Deserpentinization in Subducting Slabs: a Case Study From the Almirez Ultramafic Massif

    Science.gov (United States)

    Dilissen, Nicole; Hidas, Károly; Garrido, Carlos J.; López Sánchez-Vizcaíno, Vicente; Kahl, Wolf-Achim; Padrón-Navarta, José Alberto; Jesús Román-Alpiste, Manuel

    2017-04-01

    Serpentinite dehydration during prograde metamorphism plays a crucial role in subduction dynamics. Observations from exhumed paleo-subduction metamorphic terranes suggest that the discharge of deserpentinization fluids from the subducting slab takes place along different pathways and mechanisms [e.g. 1-3]. Analysis of intermediate-depth focal solutions in active subduction zones indicates that slabs are subjected to different principal stress fields characterized primarily by downdip compression and downdip tension [4]. Although it is well known that far field stresses play a crucial role on fluid flow channeling, their potential impact on the kinetics of serpentinite dehydration and subsequent fluid escape in subducting slabs is still poorly understood. Here, we present a detailed structural and microstructural study to investigate the relationships between far field stresses, fluid flow and high-pressure deserpentinization in the Almirez ultramafic massif (Betic Cordillera, SE Spain) [1, 2]. This massif preserves the high-pressure breakdown of antigorite (Atg-) serpentinite to prograde chlorite (Chl-) harzburgite, which are separated by a sharp isograd [2, 5]. The Chl-harzburgite reaction products show either a granofels or spinifex-like texture indicating crystallization under different overstepping of the Atg-out reaction. The two different textural types of Chl-harzburgite occur below the Atg-out isograd as alternating, meter-wide lenses with either a granofels or spinifex texture. From field measurements, we infer that during antigorite dehydration the minimum compressive stress was subnormal to the dehydration front and the paleo-slab surface. This stress field is consistent with subduction zones with slabs under downdip compression at intermediate depths [4]. The detailed microstructural study —combining µ-CT and EBSD-SEM [6]— of Chl-harzburgite across a c. 15 m wide lens reveals that the SPO and CPO of olivines with contrasting textures are strongly

  16. Springtime connections between the large-scale sea-level pressure field and gust wind speed over Iberia and the Balearics

    Directory of Open Access Journals (Sweden)

    M. L. Martín

    2011-01-01

    Full Text Available This paper investigates, by means of Singular Value Decomposition analysis, the springtime relationships between the mean sea-level pressure field over the North Atlantic and the regional wind gusts over the Iberian Peninsula, identifying the main atmospheric circulation patterns linked to gust wind speed anomaly configurations. The statistical significance of the obtained modes is investigated by means of Monte Carlo approach. The analysis highlighted that the covariability is dominated by two main large-scale features of the atmospheric circulation over the North Atlantic. The first mode relates to Iberian gust wind speeds to the Scandinavian pattern (SCAND, linking the large-scale pattern to above-normal wind gusts. The second covariability mode, associated with the North Atlantic Oscillation (NAO pattern, correlates with maximum wind speeds over Iberia. An enhanced spring NAO pattern is related to positive (negative wind gust correlations over northern (southern Iberia. To find true relationships between large-scale atmospheric field and the gust wind speeds, composite maps were built up to give an average atmospheric circulation associated with coherent wind gust variability over Iberia.

  17. Field measurement of wind pressure and wind-induced vibration of large-span spatial cable-truss system under strong wind or typhoon

    Directory of Open Access Journals (Sweden)

    ZHANG Zhihong

    2013-10-01

    Full Text Available In order to ensure wind-resistance safety of large-span pre-stressed flexible system in southeast coast area of China,and to prepare something for revising of current codes of practice or technical standards,the present paper conducts field measurement of wind pressure and wind-induced vibration of a practical and typical large-span spatial cable-truss system-lunar stadium in Yueqing city.Wind loading and wind effects on full-scale structure under strong wind or typhoon in real architectural environment can be obtained directly and effectively.Field measurement is the best way to investigate the wind loading property,wind effects,and wind-structure interactions of large-span flexible system.Measured data will be highly valuable for scientific research and practical design.On the other hand,it also provides the basis of wind-resistance safety design of this kind of tension structures.If any creative development,it would dramatically improve the research level of large-span pre-stressed flexible system in our country.

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

    Energy Technology Data Exchange (ETDEWEB)

    Pawloski, G A

    2012-06-18

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Pawloski, G A

    2012-04-25

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

  20. Ground surface deformation patterns, magma supply, and magma storage at Okmok volcano, Alaska, from InSAR analysis: 2. Coeruptive deflation, July-August 2008

    Science.gov (United States)

    Lu, Zhong; Dzurisin, Daniel

    2010-01-01

    A hydrovolcanic eruption near Cone D on the floor of Okmok caldera, Alaska, began on 12 July 2008 and continued until late August 2008. The eruption was preceded by inflation of a magma reservoir located beneath the center of the caldera and ~3 km below sea level (bsl), which began immediately after Okmok's previous eruption in 1997. In this paper we use data from several radar satellites and advanced interferometric synthetic aperture radar (InSAR) techniques to produce a suite of 2008 coeruption deformation maps. Most of the surface deformation that occurred during the eruption is explained by deflation of a Mogi-type source located beneath the center of the caldera and 2–3 km bsl, i.e., essentially the same source that inflated prior to the eruption. During the eruption the reservoir deflated at a rate that decreased exponentially with time with a 1/e time constant of ~13 days. We envision a sponge-like network of interconnected fractures and melt bodies that in aggregate constitute a complex magma storage zone beneath Okmok caldera. The rate at which the reservoir deflates during an eruption may be controlled by the diminishing pressure difference between the reservoir and surface. A similar mechanism might explain the tendency for reservoir inflation to slow as an eruption approaches until the pressure difference between a deep magma production zone and the reservoir is great enough to drive an intrusion or eruption along the caldera ring-fracture system.

  1. 2D modeling and simulation of the flow dynamics, electric field and reactions in a low-temperature, atmospheric-pressure nitrogen plasma sharp-end plate-to-plane configuration and CVD reactor

    Science.gov (United States)

    De Wilde, Juray; Lorant, Christophe; Descamps, Pierre

    2017-04-01

    In atmospheric-pressure plasma reactors, the flow dynamics can be complex, determine the reactor performance and complicate scale-up. Coupling computational fluid dynamics to the calculation of the electric field and plasma chemistry is challenging because of the numerical stiffness introduced by the difference in time scale of the different phenomena involved. Focusing on low-temperature, atmospheric-pressure pure nitrogen plasma, a model and model reduction based solution strategy to deal with the numerical stiffness are presented and evaluated. The influence of the electric field on the flow dynamics and species concentration fields is first qualitatively studied by means of 2D simulations of a sharp-end plate-to-plane configuration. Next, a specific reactor prototype for low-temperature, atmospheric-pressure plasma-enhanced chemical vapor deposition for in-line surface treatments is simulated to illustrate the importance of accounting for the detailed flow dynamics.

  2. Initial distribution of pressure and temperature in the geothermal field of Los Humeros, Puebla; Distribucion inicial de presion y temperatura del campo geotermico de Los Humeros, Puebla

    Energy Technology Data Exchange (ETDEWEB)

    Arellano Gomez, Victor M.; Garcia Gutierrez, Alfonso; Barragan Reyes, Rosa Maria; Aragon Aguilar, Alfonso; Pizano, Arturo [Instituto de Investigaciones Electricas, Temixco, Morelos (Mexico)

    2000-07-01

    In order to infer the distributions of non disturbed pressure and temperature of the reservoir fluid, a considerable amount of information originating from several disciplines was analyzed, corresponding to 42 wells of the geothermal field of Los Humeros. On the base of the analyzed data models were developed, in one and two dimensions, of the reservoir in an initial state. The models reveal the existence of at least two reservoirs. The first one and most superficial is located between 1600 and 1025 m.a.s.l. and it is a reservoir of dominant liquid. The pressure profile of this reservoir corresponds to a boiling water column approximately between 300 and 339 Celsius degrees. The second reservoir is located underneath the 850 m.a.s.l. and as far as the collected data, it can be said that it extends at least until the 100 m.a.s.l and it is estimated that it is a reservoir of low liquid saturation. For the wells that are fed from this zone of the field temperatures between 300 and 400 Celsius degrees were estimated. A table of the geology of the subsoil of the region of the Los Humeros is shown and a table where the chemical composition of the separated water is indicated and the enthalpy of some of the wells of Los Humeros, Puebla, Mexico. [Spanish] Para inferir las distribuciones de presion y temperatura no perturbadas del fluido del yacimiento, se analizo una considerable cantidad de informacion proveniente de varias disciplinas, correspondiente a 42 pozos del campo geotermico de Los Humeros. Sobre la base de los datos analizados se desarrollaron modelos, en una y dos dimensiones, del yacimiento en un estado inicial. Los modelos revelan la existencia de cuando menos dos yacimientos. El primero y mas superficial se encuentra localizado entre 1600 y 1025 m.s.n.m. y es un yacimiento de liquido dominante. El perfil de presion de este yacimiento corresponde a una columna de agua en ebullicion aproximadamente entre 300 y 339 grados centigrados. El segundo yacimiento se

  3. 泥水盾构施工引起的地面固结沉降实例研究%Case study of ground surface consolidation settlements induced by slurry shield tunnelling

    Institute of Scientific and Technical Information of China (English)

    张忠苗; 林存刚; 吴世明; 邹健; 刘俊伟

    2012-01-01

    Extensive analysis of consolidation settlements induced by slurry shield tunnelling in construction of Hangzhou Qiantang River Tunnel was executed to explore their characteristics. A practical method to distinguish the consolidation settlements from immediate settlements was put forward. Formation mechanism, influencing factors, and control measures of consolidation settlements due to slurry shield tunnelling were summarized. This case study shows that: ①Both immediate and settlement long-term ground surface settlement in the transverse direction can be fitted using Peck equation with great precision. ②The transverse ground surface consolidation settlements usually do not conform to Gaussian curves. Maximum consolidation settlements develop at the ground surface above the tunnel centre or in the vicinity, from where they descend gradually with increasing distance. ③ Consolidation settlements contribute to widening the settlement trough width. ④The time corresponding to the turning point in settlement-time curve or settlement rate-time curve is proposed to be chosen as boundary to divide the immediate and consolidation settlements. ⑤Optimized control of slurry shield excavation parameters contributes to smaller disturbances to surrounding soils, consequently lowering consolidation settlements and their duration.%通过对杭州钱塘江隧道泥水盾构施工的分析,研究了泥水盾构施工引起的地面固结沉降的特点,提出划分地层损失沉降和固结沉降的实用方法,总结了盾构施工引起扰动土体固结沉降的机理、影响因素及控制措施.分析表明:无论是地层损失沉降还是长期沉降,均可用Peck公式较好地拟合;横向地面固结沉降曲线不符合高斯曲线形式,一般隧道轴线或附近地面固结沉降最大,向两侧递减;扰动土体固结使得横向沉降槽不断拓宽;软土地区盾构隧道施工,可取地面沉降曲线或沉降速度曲线的转折点作为地层损

  4. High-Temperature and High-Pressure Pyrolysis of Hexadecane: Molecular Dynamic Simulation Based on Reactive Force Field (ReaxFF).

    Science.gov (United States)

    Chen, Zhuojun; Sun, Weizhen; Zhao, Ling

    2017-03-07

    As important products of heavy oil pyrolysis, heavier components such as gasoline and diesel supply the vast majority of energy demand through combustion, and lighter components such as ethylene and propylene are the main sources of industrial chemicals and plastic products. In this work, pyrolysis of hexadecane, as the model compound, was studied by reactive force field (ReaxFF) molecular simulation at high temperatures and high pressures. It was confirmed by unimolecular simulations that there exist eight different initial mechanisms all starting with C-C bond dissociation. The biradical mechanism was verified, through which the pyrolysis process can be accomplished within a shorter time. The enthalpy of reaction was calculated by the QM method, which was well consistent with ReaxFF calculation results. Multimolecular simulations showed that there is a strong dependency relationship between products distribution and temperature, as well as that between reaction rates and temperature. The optimal condition for ethylene formation in our work is 11.6 MPa and 2000 K, whereas it is best for hydrogen formation at conditions of 11.6 MPa and 3500 K. Kinetic analysis was performed with the activation energy of 113.03 kJ/mol and pre-exponential factor of 4.55 × 10(12), and it is in good agreement with previous work.

  5. Photo-ionization cross-section of donor-related in (In,Ga)N/GaN core/shell under hydrostatic pressure and electric field effects

    Science.gov (United States)

    El Ghazi, Haddou; John Peter, A.

    2017-04-01

    Hydrogenic-like donor-impurity related self and induced polarizations, bending energy and photo-ionization cross section in spherical core/shell zinc blende (In,Ga)N/GaN are computed. Based on the variational approach and within effective-mass and one parabolic approximations, the calculations are made under finite potential barrier taking into account of the discontinuity of the effective-mass and the constant dielectric. The photo-ionization cross section is studied according to the photon incident energy considering the effects of hydrostatic pressure, applied electric field, structure's radius, impurity's position and indium composition in the core. It is obtained that the influences mentioned above lead to either blue shifts or redshifts of the resonant peak of the photo-ionization cross section spectrum. The unusual behavior related to the structure radius is discussed which is as a consequence of the finite potential confinement. We have shown that the photo-ionization cross section can be controlled with adjusting the internal and external factors. These properties can be useful for producing some device applications such as quantum dot infrared photodetectors.

  6. Impact of Gobi desert dust on aerosol chemistry of Xi'an, inland China during spring 2009: differences in composition and size distribution between the urban ground surface and the mountain atmosphere

    Directory of Open Access Journals (Sweden)

    G. H. Wang

    2012-08-01

    Full Text Available Composition and size distribution of atmospheric aerosols from Xi'an city (~400 m, altitude in inland China during the spring of 2009 including a massive dust event on 24 April were measured and compared with a parallel measurement at the summit (2060 m, altitude of Mt. Hua, an alpine site nearby Xi'an. EC, OC and major ions in the city were 2–22 times higher than those on the mountaintop during the whole sampling period. Sulfate was the highest species in the nonevent time in Xi'an and Mt. Hua, followed by nitrate, OC and NH4+. In contrast, OC was the most abundant in the event at both sites, followed by sulfate, nitrate and Ca2+. Compared to those on the urban ground surface aerosols in the elevated troposphere over Mt. Hua contain more sulfate and less nitrate, because HNO3 is formed faster than H2SO4 and thus long-range transport of HNO3 is less significant than that of H2SO4. An increased water-soluble organic nitrogen (WSON was observed for the dust samples from Xi'an, indicating a significant deposition of anthropogenic WSON onto dust and/or an input of biogenic WSON from Gobi desert.

    As far as we know, it is for the first time to perform a simultaneous observation of aerosol chemistry between the ground surface and the free troposphere in inland East Asia. Our results showed that fine particles are more acidic on the mountaintop than on the urban ground surface in the nonevent, mainly due to continuous oxidation of SO2 to produce H2SO4 during the transport from lowland areas to the alpine atmosphere. However, we found the urban fine particles became more acidic in the event than in the nonevent, in contrast to the mountain atmosphere, where fine particles were less acidic when dust was present. The opposite changes in acidity of fine particles at both sites during the event are mostly caused by

  7. 盾构掘进速度及非正常停机对地面沉降的影响%Influences of shield advance rate and abnormal machine halt on tunnelling-induced ground surface settlements

    Institute of Scientific and Technical Information of China (English)

    林存刚; 吴世明; 张忠苗; 刘俊伟; 李宗梁

    2012-01-01

    Shield tunnelling in soft soils inevitably disturbs the surrounding environment and induces ground surface settlements. The serviceability and safety of the structures in the vicinity can be jeopardized in case that excess settlements are observed. A comprehensive understanding of the influencing factors of shield tunnelling induced ground settlements and an accurate settlement prediction are of great importance for minimizing the environment impacts of shield tunnelling. Taking the load of the shield into account, the Mindlin's solution is introduced to calculate the additional stress in soils beneath the shield, and the layer-wise summation method is applied to calculate the final one-dimensional consolidation settlement. The duration of additional stress in soils relies on the shield advance rate and its halt time, and the corresponding consolidation settlement can be calculated using the Terzaghi's one-dimensional consolidation theory. Finally, the relationship between consolidation settlements and ground surface settlements is established by Peck equation. The theory is verified by in-situ monitored ground surface settlements in construction of Hangzhou Qing-chun Road cross-river tunnel in China. These studies show that the shield advance rate and machine halt duration have a significant impact on the ground surface settlements, and the increase in shield advance rate and decrease in machine halt duration favors the settlement control.%软土中盾构隧道施工不可避免地扰动周围地层,进而引起地面沉降,沉降过大时将危及邻近建(构)筑物的正常使用和结构安全.全面理解盾构隧道施工引起的地面沉降的影响因素及对沉降的准确预测,对于减少施工环境危害十分重要.考虑盾构压重后,引入Mindlin解计算盾构下卧土层中的附加应力,采用单向压缩分层总和法计算盾构下卧土层的总固结沉降,由盾构掘进速度及停机时间确定附加应力作用时间后,应用

  8. Pressurized H2 rf Cavities in Ionizing Beams and Magnetic Fields

    Energy Technology Data Exchange (ETDEWEB)

    Chung, M.; Collura, M. G.; Flanagan, G.; Freemire, B.; Hanlet, P. M.; Jana, M. R.; Johnson, R. P.; Kaplan, D. M.; Leonova, M.; Moretti, A.; Popovic, M.; Schwarz, T.; Tollestrup, A.; Torun, Y.; Yonehara, K.

    2013-10-01

    A major technological challenge in building a muon cooling channel is operating RF cavities in multi-tesla external magnetic fields. We report the first experimental characterization of a high pressure gas-filled 805 MHz RF cavity for use with intense ionizing beams and strong external magnetic fields. RF power consumption by beam-induced plasma was investigated with hydrogen and deuterium gases with pressures between 20 and 100 atm and peak RF gradients between 5 and 50 MV/m. The energy absorption per ion pair-RF cycle ranges from 10-18 to 10-16 J. The low pressure case agrees well with an analytical model based on electron and ion mobilities. Varying concentrations of oxygen gas were investigated to remove free electrons from the cavity and reduce the RF power consumption. Measurements of the electron attachment time to oxygen and rate of ion-ion recombination were also made. Additionally, we demonstrate the operation of the gas-filled RF cavity in a solenoidal field of up to 3 T, finding no major magnetic field dependence. These results indicate that a high pressure gas-filled cavity is potentially a viable technology for muon ionization cooling.

  9. Field demonstration of an active reservoir pressure management through fluid injection and displaced fluid extractions at the Rock Springs Uplift, a priority geologic CO2 storage site for Wyoming

    Energy Technology Data Exchange (ETDEWEB)

    Jiao, Zunsheng [Univ. of Wyoming, Laramie, WY (United States)

    2017-04-05

    This report provides the results from the project entitled Field Demonstration of Reservoir Pressure Management through Fluid Injection and Displaced Fluid Extraction at the Rock Springs Uplift, a Priority Geologic CO2 Storage Site for Wyoming (DE-FE0026159 for both original performance period (September 1, 2015 to August 31, 2016) and no-cost extension (September 1, 2016 to January 6, 2017)).

  10. 基于PVDF薄膜的流场动态压力检测方法的研究%Study on dynamic pressure detection method for flow field based on PVDF film

    Institute of Scientific and Technical Information of China (English)

    阮晓东; 巴静; 陈晖; 陈文昱; 傅新

    2011-01-01

    Aiming at the problems of large size,low frequency response and arousing disturbance to the flaw field that most present liquid pressure sensors have when detecting flow field pressure of narrow space, a PVDF film-based flow field dynamic pressure detection method is proposed. Directly fabricated from an aluminum-coated PYDF film using lithographic process,the sensing element implemented in this method has been endowed with the advantages of small size, thin thickness and good flexibility, which make it applicable for the wall pressure distribution measurement for narrow gap flow field. Experimental research shows that this method is well suitable for the slight pressure fluctuation detection in the flow field,with a linearity error of ±2.3% and a sensitivity of 1.32mV/Pa.%针对检测狭小空间流场压力时,通用液体压力传感器存在体积大、频响低以及干扰流场等问题,提出一种基于聚偏氟乙烯(PVDF)薄膜的流场动态压力检测方法,该方法采用光刻工艺直接在敷镀有金属铝电极的PVDF薄膜上制作压力传感元件,该元件具有面积小、厚度薄、柔韧性好的特点,非常适合于狭小流场空间壁面压力分布的测量.试验研究表明:该方法特别适用于检测流场微小的压力波动,线性度误差为±2.3%,输出灵敏度为1.32 mV/Pa.

  11. A novel capillary electrophoresis method with pressure assisted field amplified sample injection in determination of thiol collectors in flotation process waters.

    Science.gov (United States)

    Sihvonen, T; Aaltonen, A; Leppinen, J; Hiltunen, S; Sirén, H

    2014-01-17

    A new capillary electrophoresis method was developed for the quantification of diisobutyldithiophosphate (DTP), diisobutyldithiophosphinate (DTPI) and ethyl and isobutyl xanthates (EX, IBX) all of which are used as thiol collectors in froth flotation. This method uses pressure assisted field amplified sample injection (PA-FASI) to concentrate the analytes at the capillary inlet. The background electrolyte in electrophoretic separation was 60millimolar (mM) from 3-(cyclohexylamino)propane-1-sulfonic acid (CAPS) in 40mM NaOH solution. The similar CAPS electrolyte solution has earlier been used for screening for diuretics that contained sulphonamide and/or carboxylic groups. In this study, the functional groups are xanthate, phosphate and phosphinate. The method was developed using actual flotation process waters. The results showed that the water delivered from the plant did not contain significant amount of collectors; therefore, method development was accomplished by spiking analytes in these waters. Separation of analytes was achieved in 15min. The range of quantification was 0.27-66.6mg/L (R(2) 0.9991-0.9999) for all analytes other than ethyl xanthate, for which the range was 0.09-66.6mg/L (R(2) 0.9999). LOD (S/N=3) and LOQ (S/N=10) values for DTP, DTPI, IBX and EX were 0.05, 0.07, 0.06 and 0.01mg/L and 0.16, 0.25, 0.21 and 0.04mg/L, respectively. No interference from the matrices was observed, when the method was tested at a gold concentrator plant.

  12. 压载水过滤器流场压降模拟分析%Pressure Drop Analysis of the Flow Field for Ballast Water Filter

    Institute of Scientific and Technical Information of China (English)

    徐莉萍; 马志勇; 南晓青

    2016-01-01

    CFD methods are used to analyze and calculate the pressure drop of the ballast water filter.Provide the necessary theoretical basis for the product structure design,performance improvement and thrift experimental cost.The theoretical apply of porous media in mesh modeling simplified the entity modeling of ballast water filter,with ensure the accuracy of the computing re-sults by analysis on the internal flow field in the modeling and operation.Simulation results has certain reference value for the im-provement of the domestic marine seawater filter,also contribute to the relative practical application development.%采用 CFD 软件对流体通过压载水过滤器的压降进行模拟分析,为产品的结构性能优化提供必要的理论依据,以节省产品研制成本。通过 Analysis 对其内部流场进行了建模、运算,应用多孔介质理论简化过滤器的实体建模保证计算结果准确性。对仿真数据与试验数据进行了对比分析,结果表明仿真结果有效,对国内船用海水过滤器的设计开发有一定的参考价值。

  13. Modeling of PD Mechanism in Non-uniform Field at High Pressure%高压下非均匀电场中局放机理的建模

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Partial discharges in air in non-uniform electric field occur in surroundings made of high curvature elements. The equivalent electrode system, needle-plane refers both to external components of high voltage insulating systems and to micro sharpness in the internal structure of those systems. The ionization zone, accumulation of space charge and formation of corresponding current pulses depend on electrode configuration, voltage level, pressure, temperature and humidity of air. The assessment of pressure influence on discharge mechanism in non-homogenous electric field has been performed on the basis of empirical density distributions of discharge charges at different voltage levels, electrode distance, curvature of high voltage electrode and taking into account solid dielectric barrier in serial configuration. The measurement results obtained at variable voltage level yield the influence of electric field strength in the needle electrode zone. While increasing voltage, a deviation from normal distribution may be observed that reveals other forms of discharge.

  14. Effects of different ground surface mulch under subsoiling on potato yield and water use efficiency%深松条件下不同地表覆盖对马铃薯产量及水分利用效率的影响

    Institute of Scientific and Technical Information of China (English)

    李荣; 侯贤清

    2015-01-01

    microclimate, and significantly increase the yield and water use efficiency of crops. In order to explore the effects of different ground surface methods combined with subsoiling tillage on soil physical characteristics, potato growth, yield and water use efficiency, field fixed position experiment was conducted to study the effect of mulching tillage on soil volume quality, aggregate, water, potato yield and water use efficiency in arid areas of southern Ningxia between 2013 and 2015. The field experiment consisted of the following 4 treatments: straw mulch with subsoiling tillage (ST+JM), plastic film mulch with subsoiling tillage (ST+DM), no mulch with subsoiling tillage (ST), and no mulch with conventional tillage (CT). The no mulch with conventional tillage was used as the control. Our study results showed that, the soil volume quality of the 0–40 cm soil layer under subsoiling combined with mulch was effectively decreased compared with conventional tillage, while the soil total porosity was greatly improved, and especially the straw mulch with subsoiling treatment was the best. During the study, the mean soil volume quality (0–40 cm) under straw mulch with subsoiling treatment was significantly (P0.25 mm elastic-stable macroaggregates in the 0–40 cm soil layer compared with conventional tillage. The amounts of >0.25 mm aggregates (0–40 cm) under straw mulch with subsoiling and plastic film mulch with subsoiling treatments were significantly (P<0.05) increased by 30.7% and 17.4% respectively compared with the conventional tillage treatment. Subsoiling combined with ground surface mulch greatly improved soil water storage in the 0–200 cm soil layer during the growing stage of potato. The straw mulch with subsoiling and plastic film mulch with subsoiling treatments had the best effect on water conservation; the soil water storage in the 0–200 cm soil layer under the plastic film mulch with subsoiling treatment was significantly higher than the conventional

  15. 背压下旋转分配器间隙流场特性分析%Analysis for gap flow field characteristics of rotary distributor under back pressure

    Institute of Scientific and Technical Information of China (English)

    唐华存; 陈占福

    2011-01-01

    Keeping the oil return path of rotary distributor under a certain back pressure can improve the working life. The formula of flow, pressure, loading capacity and oil film stiffness in gap flow field is derived in this paper, the variation characteristics of fluid in the gap flow field is obtained when the back pressure increases, and then the finite element analysis of gap flow field is adopted with Fluent to verify the theoretical formula. The conclusion is that the back pressure can be properly increased while the variable load of rotary distributor is satisfied.%旋转分配器工作时保持回油通路一定的背压能够提高其使用寿命.本文首先推导出间隙流场中流量、压力、承载能力和油膜刚度的计算公式,得出在增加背压的情况下间隙流场内流体特性的变化,然后运用fluent对间隙流场进行有限元分析,验证了理论公式.在满足旋转分配器工作变载荷的情况下,可以适当增加背压.

  16. Dependence of the open-closed field line boundary in Saturn's ionosphere on both the IMF and solar wind dynamic pressure: comparison with the UV auroral oval observed by the HST

    Directory of Open Access Journals (Sweden)

    E. S. Belenkaya

    2008-02-01

    Full Text Available We model the open magnetic field region in Saturn's southern polar ionosphere during two compression regions observed by the Cassini spacecraft upstream of Saturn in January 2004, and compare these with the auroral ovals observed simultaneously in ultraviolet images obtained by the Hubble Space Telescope. The modelling employs the paraboloid model of Saturn's magnetospheric magnetic field, whose parameters are varied according to the observed values of both the solar wind dynamic pressure and the interplanetary magnetic field (IMF vector. It is shown that the open field area responds strongly to the IMF vector for both expanded and compressed magnetic models, corresponding to low and high dynamic pressure, respectively. It is also shown that the computed open field region agrees with the poleward boundary of the auroras as well as or better than those derived previously from a model in which only the variation of the IMF vector was taken into account. The results again support the hypothesis that the auroral oval at Saturn is associated with the open-closed field line boundary and hence with the solar wind interaction.

  17. On the Behavior of a Shear-Coaxial Jet, Spanning Sub- to Supercritical Pressures, with and without an Externally Imposed Transverse Acoustic Field

    Science.gov (United States)

    2006-05-01

    processes. For example, Zuo and Stenby [13] used a modified form of the Soave Redlich Kwong equation of state along with the assumption of a linear density...causes combustion instability, but all have limited ranges of applicability (see Hulka and Hutt [3]). 4 Liquid rocket engines, burning cryogenic...propulsion applications were performed at low pressure, even though many liquid rocket engines are operated at pressures well above the critical

  18. Variation of radio field strength and radio horizon distance over three stations in Nigeria

    Science.gov (United States)

    Adediji, A. T.; Ismail, Mahamod; Mandeep, J. S.

    2014-03-01

    In this work, we present seasonal results of radio field strength and radio horizon distance derived from the computation of surface refractivity through in-situ measurement of temperature, relative humidity and pressure across three stations (Akure, Minna and Enugu) in Nigeria. The measurements of the tropospheric parameters were made using a Davis Wireless Weather Station (Integrated Sensor Suite, ISS) installed on the ground surface at each of the stations. The study utilized data for two years of measurement (January 2008-December 2009). Results show that the values of surface refractivity were low during the dry season months and high during the wet season months. The lowest values of 323, 313 and 281 N-units were observed in February for Akure, Enugu and Minna respectively, while maximum values of 372, 375 and 365 N-units were observed in September, October and August for the respective locations. Also, the average value of field strength variability was found to be 6.67, 5.62 and 7.48 for Akure, Enugu and Minna respectively.

  19. Impurity-related optical properties in rectangular-transverse section GaAs-Ga{sub 1-x}Al{sub x}As quantum well wires: Hydrostatic pressure and electric field effects

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, J.W.; Duque, C.A. [Instituto de Fisica, Universidad de Antioquia, AA 1226, Medellin (Colombia); Lopez, S.Y. [Facultad de Educacion, Universidad de Antioquia, AA 1226, Medellin (Colombia); Rodriguez, A.H. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico (UNAM), Apdo. Postal 20-364, San Angel 01000, Mexico DF (Mexico); Porras-Montenegro, N. [Departamento de Fisica, Universidad del Valle, AA 25360, Cali (Colombia)

    2007-01-15

    Using a variational procedure within the effective mass approximation, we have calculated the influence of an applied electric field and hydrostatic pressure on the shallow-impurity-related optical properties in a rectangular-transverse section GaAs-Ga{sub 1-x}Al{sub x}As quantum well wire. The electric field is applied in the plane of the transverse section of the wire and different angular directions have been considered. The results presented are for the impurity binding energy, its corresponding density of impurity states, and impurity-related transition energy and polarizability. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  20. Shape estimation of the buried body from the ground surface potential distributions generated by current injection; Tsuryu ni yoru chihyomen den`i bunpu wo riyoshita maizobutsu keijo no suitei

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Y.; Okamoto, Y. [Chiba Institute of Technology, Chiba (Japan); Noguchi, K. [Waseda University, Tokyo (Japan); Teramachi, Y. [University of Industrial Technology, Kanagawa (Japan); Akabane, H.; Agu, M. [Ibaraki University, Ibaraki (Japan)

    1996-10-01

    Ground surface potential distribution generated by current injection was studied to estimate the shape of buried bodies. Since the uniform ground system including a homogeneous buried body is perfectly determined with the surface shape of a buried body and resistivities in/around a buried body, inversion is easy if the surface shape is described with some parameters. N electrodes are arranged in 2-D grid manner on the ground, and two electrodes among them are used for current injection, while the others for measurement of potentials. M times of measurements are repeated while changing combination of electrodes for current injection. The potential distribution measured by the mth electrode pair is represented by N-2 dimensional vectors. The square error between this distribution and calculated one is the function of k parameters on the surface shape and resistivities on a buried body. Both shape and resistivities can be estimated by solving an optimum value problem using the square error as evaluation function. Analysis is easy for a spherical body with 6 unknown parameters, however, it is difficult for more complex bodies than elliptical one or more than two bodies. 5 refs., 9 figs.

  1. The Control of Ground Surface Settlement in the Design of Foundation Pit Supporting around Shallow Foundation Buildings%浅基础建筑物相邻的基坑支护设计中地表变形控制

    Institute of Scientific and Technical Information of China (English)

    刘立东

    2012-01-01

    Through analyzing the effect of the design of one deep foundation pit supporting project on peripheral six-layer shallow foundation building in Yancheng city, in the accordance with the relevant existing national engineering codes, this paper considered the deformation of both soil and buildings a- round the foundation pit, and explored how to calculate and control the ground surface settlement around the foundation pit in order to ensure the safety of the surrounding buildings and meanwhile achieve opti- mal economic results.%通过对盐城一深基坑支护设计对周边六层浅基础建筑的影响分析,结合现有相关的国家规范,从基坑周边土体和建筑物变形两个方面综合分析,阐述了深基坑设计过程中,如何对支护周边地表沉降进行计算控制,以保证周边建筑物的安全,同时取得最优经济效益。

  2. 3 D seismic exploration technology in deep mining area under complicated ground surface%复杂地表深部采区三维地震勘探技术∗

    Institute of Scientific and Technical Information of China (English)

    孙希杰; 王静; 李淅龙; 叶树刚

    2016-01-01

    恒源煤矿深部采区进行三维地震勘探的主要难点为地表及地质构造复杂、煤层埋藏深且较薄、信噪比和分辨率低。针对以上难点,采取了优化观测系统、Klseis 软件实时监测的设计措施,深井、小药量激发,村庄内检波点实测铺设的采集措施保证了覆盖次数的均匀合理。经精细处理及综合动态解释,取得了较显著的地质成果。%The complicated ground surface and geologic structure,deep and thin coal seam, low signal to noise ratio and resolution ratio were the main difficulties of 3D seismic exploration in deep mining area of Hengyuan Coal Mine��Aiming at above difficulties,observing system opti-mization and real-time monitoring by Klseis software were adopted as designing measures,drill-ing and small dosage stimulating and actual measurement of detection points in the villages were adopted as data collection methods to ensure the uniform and reasonable of coverage times��By precise processing and comprehensive dynamic interpretation,remarkable geology results were a-chieved.

  3. Unified Application of Vapor Screen Flow Visualization and Pressure Sensitive Paint Measurement Techniques to Vortex- and Shock Wave-Dominated Flow Fields

    Science.gov (United States)

    Erickson, Gary E.

    2010-01-01

    Laser vapor screen (LVS) flow visualization and pressure sensitive paint (PSP) techniques were applied in a unified approach to wind tunnel testing of slender wing and missile configurations dominated by vortex flows and shock waves at subsonic, transonic, and supersonic speeds. The off-surface cross-flow patterns using the LVS technique were combined with global PSP surface static pressure mappings to characterize the leading-edge vortices and shock waves that coexist and interact at high angles of attack. The synthesis of LVS and PSP techniques was also effective in identifying the significant effects of passive surface porosity and the presence of vertical tail surfaces on the flow topologies. An overview is given of LVS and PSP applications in selected experiments on small-scale models of generic slender wing and missile configurations in the NASA Langley Research Center (NASA LaRC) Unitary Plan Wind Tunnel (UPWT) and 8-Foot Transonic Pressure Tunnel (8-Foot TPT).

  4. Unified Application Vapor Screen Flow Visualization and Pressure Sensitive Paint Measurement Techniques to Vortex- and Shock Wave-Dominated Flow Fields

    Science.gov (United States)

    Erickson, Gary E.

    2008-01-01

    Laser vapor screen (LVS) flow visualization and pressure sensitive paint (PSP) techniques were applied in a unified approach to wind tunnel testing of slender wing and missile configurations dominated by vortex flows and shock waves at subsonic, transonic, and supersonic speeds. The off-surface cross-flow patterns using the LVS technique were combined with global PSP surface static pressure mappings to characterize the leading-edge vortices and shock waves that coexist and interact at high angles of attack (alpha). The synthesis of LVS and PSP techniques was also effective in identifying the significant effects of passive surface porosity and the presence of vertical tail surfaces on the flow topologies. An overview is given of LVS and PSP applications in selected experiments on small-scale models of generic slender wing and missile configurations in the NASA Langley Research Center (NASA LaRC) Unitary Plan Wind Tunnel (UPWT) and 8-Foot Transonic Pressure Tunnel (8-Foot TPT).

  5. Pressure ulcers

    National Research Council Canada - National Science Library

    Reddy, Madhuri

    2011-01-01

    Unrelieved pressure or friction of the skin, particularly over bony prominences, can lead to pressure ulcers in up to one third of people in hospitals or community care, and one fifth of nursing home residents...

  6. Pressure Sores

    Science.gov (United States)

    Pressure sores are areas of damaged skin caused by staying in one position for too long. They ... wheelchair, or are unable to change your position. Pressure sores can cause serious infections, some of which ...

  7. Pressure ulcers

    OpenAIRE

    Monfre, Jill M.

    2011-01-01

    Unrelieved pressure or friction of the skin, particularly over bony prominences, can lead to pressure ulcers, which affect up to one third of people in hospitals or community care, and one fifth of nursing home residents. Pressure ulcers are more likely in people with reduced mobility and poor skin condition, such as older people or those with vascular disease.

  8. Simultaneous effects of hydrostatic pressure and applied electric field on the impurity-related self-polarization in GaAs/Ga{sub 1-x}Al{sub x}As multiple quantum wells

    Energy Technology Data Exchange (ETDEWEB)

    Restrepo, R.L.; Miranda, Guillermo L. [Fisica Teorica y Aplicada, Escuela de Ingenieria de Antioquia, A.A. 7516 Medellin (Colombia); Duque, C.A., E-mail: cduque_echeverri@yahoo.e [Instituto de Fisica, Universidad de Antioquia, A.A. 1226 Medellin (Colombia); Mora-Ramos, M.E. [Facultad de Ciencias, Universidad Autonoma del Estado de Morelos, Av. Universidad 1001, CP 62209 Cuernavaca, Morelos (Mexico)

    2011-05-15

    A detailed theoretical study of the combined effects of hydrostatic pressure and in-growth direction applied electric field on the binding energy and self-polarization of a donor impurity in a system of GaAs-(Ga,Al)As coupled square quantum wells is presented. The study is performed in the framework of the effective mass and parabolic band approximations and using a variational procedure. The electron effective mass, the dielectric constant, the barrier height, the well sizes, all them varying with the hydrostatic pressure are taken into account within the study. The results obtained show that the impurity binding energy and its self-polarization bear strong dependencies with the hydrostatic pressure, the strength of the applied electric field, the width of the confining potential barriers, and the impurity position. - Research highlights: {yields} Impurity binding energy and self-polarization have a conjugate behavior in MQWs. {yields} Binding energy (self-polarization) is an increasing (decreasing) function of HP. {yields} For on-center impurity, the binding energy decreases with EF. {yields} For on-center impurity the self-polarization increases with EF.

  9. Impact of Gobi desert dust on aerosol chemistry of Xi'an, inland China during spring 2009: differences in composition and size distribution between the urban ground surface and the mountain atmosphere

    Directory of Open Access Journals (Sweden)

    G. H. Wang

    2013-01-01

    Full Text Available Composition and size distribution of atmospheric aerosols from Xi'an city (~400 m, altitude in inland China during the spring of 2009 including a massive dust event on 24 April were measured and compared with a parallel measurement at the summit (2060 m, altitude of Mt. Hua, an alpine site nearby Xi'an. EC (elemental carbon, OC (organic carbon and major ions in the city were 2–22 times higher than those on the mountaintop during the whole sampling period. Compared to that in the non-dust period a sharp increase in OC was observed at both sites during the dust period, which was mainly caused by an input of biogenic organics from the Gobi desert. However, adsorption/heterogeneous reaction of gaseous organics with dust was another important source of OC in the urban, contributing 22% of OC in the dust event. In contrast to the mountain atmosphere where fine particles were less acidic when dust was present, the urban fine particles became more acidic in the dust event than in the non-dust event, mainly due to enhanced heterogeneous formation of nitrate and diluted NH3. Cl and NO3 in the urban air during the dust event significantly shifted toward coarse particles. Such redistributions were further pronounced on the mountaintop when dust was present, resulting in both ions almost entirely staying in coarse particles. On the contrary, no significant spatial difference in size distribution of SO42− was found between the urban ground surface and the mountain atmosphere, which dominated in the fine mode (<2.1 μm during the nonevent and comparably distributed in the fine (<2.1 μm and coarse (>2.1 μm modes during the dust event.

  10. Magnetostrictive Pressure Regulating System

    Science.gov (United States)

    Richard, James A. (Inventor); Pickens, Herman L. (Inventor)

    2013-01-01

    A magnetostrictive pressure regulating system includes a magnetostrictive valve that incorporates a magnetostrictive actuator with at least one current-carrying coil disposed thereabout. A pressure force sensor, in fluid communication with the fluid exiting the valve, includes (i) a magnetostrictive material, (ii) a magnetic field generator in proximity to the magnetostrictive material for inducing a magnetic field in and surrounding the magnetostrictive material wherein lines of magnetic flux passing through the magnetostrictive material are defined, and (iii) a sensor positioned adjacent to the magnetostrictive material and in the magnetic field for measuring changes in at least one of flux angle and flux density when the magnetostrictive material experiences an applied force that is aligned with the lines of magnetic flux. The pressure of the fluid exiting the valve causes the applied force. A controller coupled to the sensor and to the current-carrying coil adjusts a current supplied to the current-carrying coil based on the changes so-measured.

  11. Hole burning with pressure and electric field: A window on the electronic structure and energy transfer dynamics of bacterial antenna complexes

    Energy Technology Data Exchange (ETDEWEB)

    Wu, H.M.

    1999-02-12

    Light-harvesting (LH) complexes of cyclic (C{sub n}) symmetry from photosynthetic bacteria are studied using absorption and high pressure- and Stark-hole burning spectroscopies. The B800 absorption band of LH2 is inhomogeneously broadened while the B850 band of LH2 and the B875 band of the LH1 complex exhibit significant homogeneous broadening due to ultra-fast inter-exciton level relaxation. The B800{r_arrow}B850 energy transfer rate of ({approximately}2 ps){sup {minus}1} as determined by hole burning and femtosecond pump-probe spectroscopies, is weakly dependent on pressure and temperature, both of which significantly affect the B800-B850 energy gap. The resilience is theoretically explained in terms of a modified Foerster theory with the spectral overlap provided by the B800 fluorescence origin band and weak vibronic absorption bands of B850. Possible explanations for the additional sub-picosecond relaxation channel of B800 observed with excitation on the blue side of B800 are given. Data from pressure and temperature dependent studies show that the B800 and B850 bacteriochlorophyll a (BChl a) molecules are weakly and strongly excitonically coupled, respectively, which is consistent with the X-ray structure of LH2. The B875 BChl a molecules are also strongly coupled. It is concluded that electron-exchange, in addition to electrostatic interactions, is important for understanding the strong coupling of the B850 and B875 rings. The large linear pressure shifts of {approximately}{minus}0.6 cm{sup {minus}1}/MPa associated with B850 and B875 can serve as important benchmarks for electronic structure calculations.

  12. Planets under pressure

    Science.gov (United States)

    Jeanloz, Raymond

    2009-04-01

    Deep inside the planet Jupiter, diamonds hail down from hydrocarbon clouds as intense atmospheric pressures break methane into its atomic components. Further in - but still only 15% of the way to the planet's centre - the pressure reaches a million times that of the Earth's atmosphere. This is enough to transform hydrogen from the transparent, insulating gas we know at our planet's surface into a metallic fluid that sustains Jupiter's huge magnetic field. Even diamond is not forever: at pressures of 8-10 million atmospheres it is transformed into an opaque, metallic form of carbon, rather than the familiar transparent crystal.

  13. Bending and turbulent enhancement phenomena of neutral gas flow containing an atmospheric pressure plasma by applying external electric fields measured by schlieren optical method

    Science.gov (United States)

    Yamada, Hiromasa; Yamagishi, Yusuke; Sakakita, Hajime; Tsunoda, Syuichiro; Kasahara, Jiro; Fujiwara, Masanori; Kato, Susumu; Itagaki, Hirotomo; Kim, Jaeho; Kiyama, Satoru; Fujiwara, Yutaka; Ikehara, Yuzuru; Ikehara, Sanae; Nakanishi, Hayao; Shimizu, Nobuyuki

    2016-01-01

    To understand the mechanism of turbulent enhancement phenomena of a neutral gas flow containing plasma ejected from the nozzle of plasma equipment, the schlieren optical method was performed to visualize the neutral gas behavior. It was confirmed that the turbulent starting point became closer to the nozzle exit, as the amplitude of discharge voltage (electric field) increased. To study the effect of electric field on turbulent enhancement, two sets of external electrodes were arranged in parallel, and the gas from the nozzle was allowed to flow between the upper and lower electrodes. It was found that the neutral gas flow was bent, and the bending angle increased as the amplitude of the external electric field increased. The results obtained using a simple model analysis roughly coincide with experimental data. These results indicate that momentum transport from drifted ions induced by the electric field to neutral particles is an important factor that enhances turbulence.

  14. [Field observation on the effect of low-sodium and high-potassium salt substitute on blood pressure in the rural community-based population in China].

    Science.gov (United States)

    Zhang, Gao-hui; Ma, Ji-xiang; Guo, Xiao-lei; Dong, Jing; Chen, Xi; Zhang, Ji-yu; Su, Jun-ying; Tang, Jun-li; Xu, Ai-qiang

    2011-09-01

    To investigate the effect of commercial low-sodium and high-potassium salt substitutes on blood pressure in the rural community-based population in China. We conducted a quasi-experiment on 411 adults, who were 30 to 60 years of age, in 2 rural communities from Laiwu city in Shandong province of China on data from blood pressure screening. The subjects were divided into 2 groups: high blood pressure (HBP) and non-HBP (NHBP). Both groups and their family members took a low-sodium and high-potassium salt substitute for 3 months to replace the normal salt in their bodies. Blood pressure (BP) and 24-hour urinary sodium and potassium were measured regularly in the 2 groups. There was a continuously decreasing trend for BP at the end of the first month. Three months later, the mean BP decreased by 7.4 mm Hg (1 mm Hg = 0.133 kPa, t = 10.096, P = 0.000) for SBP and 3.8 mm Hg (t = 8.017, P = 0.000) for DBP in the HBP group, when compared to a 1.2 mm Hg (t = 2.507, P = 0.007) decrease on SBP and 1.0 mm Hg (t = 2.987, P = 0.002) on DBP in the NHBP group. The mean urinary sodium had a decrease of 15.5 mmol/24 h (t = 1.803, P = 0.037), but the urinary potassium increased by 4.2 mmol/24 h (t' = 2.132, P = 0.018). The result of urinary sodium appeared to be as follows: potassium ratio (Na(+)/K(+)) decreased by 1.2 (t = 2.786, P = 0.003) in the HBP group. However, in NHBP group, the mean urinary sodium decreased by 1.7 mmol/24 h (t = 0.211, P = 0.417) and urinary potassium increased by 3.7 mmol/24 h (t' = 2.207, P = 0.015), together with the decrease of Na(+)/K(+) by 0.7 (t = 1.818, P = 0.036). Results from our study clearly demonstrated that the intake of low-sodium and high-potassium salt substitute could effectively reduce the BP with good compliance among adults in the rural community-based population in China. This was an effective but non-medical method to prevent and control the high blood pressure.

  15. Structural Properties of MgSiO3 Perovskite, Twin Walls and Their Binding to Oxygen Vacancies at High Pressures from Force Field Simulations

    Science.gov (United States)

    Goncalves-Ferreira, L.; Redfern, S. A.; Artacho, E.

    2007-12-01

    Aiming to understand possible origins of seismic wave attenuation and variations in the quality factor (Q) of minerals at the Earth's interior, it has been accepted that the friction in the motion of twin domain walls under applied stress leads to a reduction in Q [1]. To interpret this behaviour one must first appreciate the influence of pressure on wall motion and dynamics. Experimental observations of twin wall motion at high pressure are difficult at present. For this reason, we have undertaken a computational study of wall structure and dynamics in MgSiO3 perovskite, in the absence or presence of defects, as a function of pressure between 0 and 140 GPa. This work is based on previous studies on CaTiO3 perovskite [2,3] (symmetry Pbnm) with 7800 atoms and orthorhombic periodic boundary conditions. It has been geometrically adapted to lower mantle's MgSiO3 perovskite. The system comprises two (100) ferroelastic twin walls separated by 34.2 Å, relaxed within a variable supercell of 26x10x6 unit cells, with the rigid ion set of interatomic potentials with partial ionic charges employed by Alfredsson et al., 2005 [4]. The degree of distortion in the system is manifest in the octahedral tilting angles along each of the crystallographic directions. The octahedral tilting orientations close to the walls are well described by the behaviour of two order parameters: the main one, defining the wall, goes as α tanh(2(x - x')/w) , where α = 11.14° is the bulk value for the tilt, and w = 11.11 Å is the wall width. The secondary order parameters describe a slight breather at the wall. As wall dynamics are influenced by the presence of oxygen vacancies, we have calculated their binding energies to the described twin walls as a function of pressure. We find that this binding strongly depends on the vacancy disposition. For a vacancy between Si atoms in an axis perpendicular to the wall the binding energy is 1.09 eV at zero pressure. For vacancies along Si-Si axes parallel

  16. Pressure drop and heat transfer of a mercury single-phase flow and an air-mercury two-phase flow in a helical tube under a strong magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Minoru E-mail: mtakahas@nr.titech.ac.jp; Momozaki, Yoichi

    2000-11-01

    For the reduction of a large magneto-hydrodynamic (MHD) pressure drop of a liquid metal single-phase flow, a liquid metal two-phase flow cooling system has been proposed. As a fundamental study, MHD pressure drops and heat transfer characteristics of a mercury single-phase flow and an air-mercury two-phase flow were experimentally investigated. A strong transverse magnetic field relevant to the fusion reactor conditions was applied to the mercury single-phase flow and the air-mercury two-phase flow in a helically coiled tube that was inserted in the vertical bore of a solenoidal superconducting magnet. It was found that MHD pressure drops of a mercury single-phase flow in the helically coiled tube were nearly equal to those in a straight tube. The Nusselt number at an outside wall was higher than that at an inside wall both in the mercury single-phase flow in the absence and presence of a magnetic field. The Nusselt number of the mercury single-phase flow decreased, increased and again decreased with an increase in the magnetic flux density. MHD pressure drops did not decrease appreciably by injecting air into a mercury flow and changing the mercury flow into the air-mercury two-phase flow. Remarkable heat transfer enhancement did not appear by the air injection. The injection of air into the mercury flow enhanced heat transfer in the ranges of high mercury flow rate and low magnetic flux density, possibly due to the agitation effect of air bubbles. The air injection deteriorated heat transfer in the range of low mercury flow rates possibly because of the occupation of air near heating wall.

  17. 微流量控压钻井系统的研制与现场试验%Development and field test of micro-flux control pressure drilling system

    Institute of Scientific and Technical Information of China (English)

    郭元恒; 曾桂元; 李勇

    2012-01-01

    Micro-flux control pressure drilling technology is advanced today. The annulus pressure of well pore can be real-time monitored and controlled precisely in closed loop, by small variation of flux in inlet and outlet, annulus pressure surveillance while drilling, automatically throttle adjusting return pressure and pressure compensation in ground. Through development of micro-flux control pressure Drilling and field trial, the matching equipment has been completed, to form a technological system. The field trial mainly bases on the Micro Flux Control-MFC to effectively prevent the incursion of formation fluid, and reduce the possibility of well kick, well loss, and decrease the non-production aging, improving the economic efficiency of drilling-well, as well as the security of drilling operation and efficiency in complicated condition. The application of technology successfully on site has in complicated formation has accumulated the experience, which can be an example for the technology.%微流量精细控压钻井技术是当今世界钻井前沿技术之一,主要是通过进出口流量的微小变化、随钻环空压力监测、地面自动节流调整及压力补偿等手段,实现环空压力的实时监测与精确控制.通过微流量精细控压钻井系统的研制和现场应用,完善微流量控压钻井设备配套并形成技术体系,现场试验主要是利用“微流量控压钻井系统”及时发现和处理井下复杂情况,减少井涌、井漏和降低钻井非生产时间等,提高钻井安全性和经济性,从而提高复杂地层的钻井作业效率.其现场成功实践为复杂地层钻进积累了经验.

  18. Implementation and research on the reconstruction algorithms of pressure fields based on PIV%基于PIV技术的压力场重构算法实现与研究

    Institute of Scientific and Technical Information of China (English)

    刘顺; 徐惊雷; 俞凯凯

    2016-01-01

    The basic principles and the corresponding algorithms of the finite volume method, the direct integral method and the Poisson equation method are introduced in detail,which are used to reconstruct the pressure fields based on PIV velocity fields.The instantaneous velocity fields of two incompressible flows,including the pipe flow with a sudden expansion and the flow around a square,are selected to study the influence of picture noise,velocity error,interpolation methods,the type and the precision of boundary conditions on reconstructed pressure fields by using different reconstruction algorithms.Finally,the transient pressure distributions of the pipe flow with a sudden expansion at 20ms are obtained by using the three algorithms respectively as well as the CFD.It shows that the finite volume method and the direct integral method are easily affected by noise to produce rude shocks,but maintain high accuracy in a larger range of error in velocity fields while they can get higher precision of reconstructed pressure fields with bilinear in-terpolation;the Poisson equation method isn’t easily affected by noise so it produces few shocks, and has great advantages with the accurate PIV velocity fields while it can get higher precision of reconstructed pressure fields with bicubic interpolation;by measuring only several pressure points on the boundaries,the mixed boundary condition gets the accurate reconstructed pressure fields which are close to those of the Dirichlet boundary condition and far better than those of the Neumann boundary condition;the error of boundary conditions reduces the precision of recon-structed pressure fields,which is more severe than the error of velocity fields.%介绍了有限容积法、直接积分法和Poisson方程法3种基于PIV瞬时速度场重构压力场的基本原理以及相应的计算方法,选取管流突扩流场和偏置方块绕流流场两个不可压缩流场的瞬时速度场数据,采用上述3种压力场重构算

  19. Evaluation of the scattered pressure due to infinite rigid cylinders, infinite elastic cylindrical shells, and rigid spheres in the presence of an ambient noise field

    Science.gov (United States)

    Honeycutt, Rebecca L.; Johnson, Steven J.

    1993-04-01

    The sound scattering due to an ambient noise field, approximated by a squared cosine function, is considered for infinite rigid and elastic cylinders and rigid spheres. For the cylinders, it is assumed that the acoustic wave front is parallel to the axis of the cylinder (informally incident). For this assumption, a closed form expression for the scattered sound field-to-incident ambient noise field (signal-to-noise) ratio is obtained not only for the cosine squared directivity, but for any arbitrary directivity which can be expressed in terms of a Fourier series. For the sphere, it is assumed that the noise is circumferentially symmetric which leads to a closed form expression for the signal-to-noise ratio due to a cosine squared directivity.

  20. Pressure Core Characterization

    Science.gov (United States)

    Santamarina, J. C.

    2014-12-01

    Natural gas hydrates form under high fluid pressure and low temperature, and are found in permafrost, deep lakes or ocean sediments. Hydrate dissociation by depressurization and/or heating is accompanied by a multifold hydrate volume expansion and host sediments with low permeability experience massive destructuration. Proper characterization requires coring, recovery, manipulation and testing under P-T conditions within the stability field. Pressure core technology allows for the reliable characterization of hydrate bearing sediments within the stability field in order to address scientific and engineering needs, including the measurement of parameters used in hydro-thermo-mechanical analyses, and the monitoring of hydrate dissociation under controlled pressure, temperature, effective stress and chemical conditions. Inherent sampling effects remain and need to be addressed in test protocols and data interpretation. Pressure core technology has been deployed to study hydrate bearing sediments at several locations around the world. In addition to pressure core testing, a comprehensive characterization program should include sediment analysis, testing of reconstituted specimens (with and without synthetic hydrate), and in situ testing. Pressure core characterization technology can be used to study other gas-charged formations such as deep sea sediments, coal bed methane and gas shales.

  1. Peer Pressure

    Science.gov (United States)

    ... who are unsure of themselves, new to the group, or inexperienced with peer pressure may also be more likely to give in. ... stand that makes you look uncool to your group. But these situations can be ... up to peer pressure, but it does take courage — yours: Listen to ...

  2. Development of automated welding processes for field fabrication of thick-walled pressure vessels: electron beam method. Sixth quarterly report, January 1-March 31, 1979

    Energy Technology Data Exchange (ETDEWEB)

    Weber, C.M.

    1979-01-01

    Research is reported of a project to develop and demonstrate an electron beam welding procedure for welding 8'' thick SA 387 Grade 22 Class 2 (2-1/4 Cr-1 Mo) steel. A total of 414 welds have been made to date. Partial penetration welding procedures capable of producing defect-free, 4'' welds have been developed in the horizontal position. Beam oscillation conditions strongly influence welding performance. Defect-free, partial penetration welds have been made at vacuum pressures of up to 30 microns. Several 8'' thick, defect-free welds have been made in the horizontal position. Attempts to produce defect-free, partial penetration welds in the vertical position have been unsuccessful.

  3. 年龄与地面性质对高处坠落伤致伤规律及其严重度的影响%Impacts of age and ground surface on injury caused by fall from heights

    Institute of Scientific and Technical Information of China (English)

    蔡贤华; 刘曦明; 谭宗奎; 徐峰; 汪国栋; 黄继锋; 王庆; 王华松; 魏世隽

    2015-01-01

    Objective To investigate the impacts of age and ground surface on the injury caused by fall from heights.Methods A retrospective study was carried out to analyze the 1,230 patients who had been treated at our department for injury caused by falling from heights from January 1996 to December 2006.They were 925 males and 305 females,aged from 1 to 86 years (average,38.5 years).The injury was evaluated by revised injury severity score (RISS).The impacts of age (< 15 years,15 to 50 years and > 50 years) and ground surface (soft ground and hard ground) on the injury were analyzed.Results Of the 287 patients of < 15 years old,81.18% had craniocerebral and maxillofacial injury.Of the 722 patients of 15 to 50 years old,50.13% had craniocerebral and maxillofacial injury,20.22% spinal injury,13.57% chest injury,38.23% lower limb injury,and 23.27% upper limb injury.Of the 221 patients of > 50 years,43.44% had craniocerebral and maxillofacial injury,22.17% spinal injury,26.70% chest injury,33.48% lower limb injury,and 16.74% upper limb injury.There were significant differences among the 3 age groups regarding injury location and RISS score (P < 0.05).The proportions of patients falling on the soft ground with multi-injury [23.91% (22/92)] and with RISS≥ 16 [28.26% (26/92)] were significantly lower than those falling on the hard ground [46.15% (36/78) and 52.56% (41/78)] (P < 0.05).Conclusions Moderate craniocerebral and maxillofacial injury were common in the patients of < 15 years old.Patients of ≥ 15 years old were commonly afflicted by moderate to severe spinal,chest and lower limb injuries.Falling on a hard ground caused a much more severe injury than falling on a soft ground.%目的 探讨年龄与地面性质对高处坠落伤致伤规律及其严重度的影响,以期提高高处坠落伤的诊断与救治水平. 方法 回顾性分析1996年1月至2006年12月收治的1 230例高处坠落伤患者资料,男925例,女305

  4. Optimization of wall thickness and lay-up for the shell-like composite structure loaded by non-uniform pressure field

    Science.gov (United States)

    Shevtsov, S.; Zhilyaev, I.; Oganesyan, P.; Axenov, V.

    2017-01-01

    The glass/carbon fiber composites are widely used in the design of various aircraft and rotorcraft components such as fairings and cowlings, which have predominantly a shell-like geometry and are made of quasi-isotropic laminates. The main requirements to such the composite parts are the specified mechanical stiffness to withstand the non-uniform air pressure at the different flight conditions and reduce a level of noise caused by the airflow-induced vibrations at the constrained weight of the part. The main objective of present study is the optimization of wall thickness and lay-up of composite shell-like cowling. The present approach assumes conversion of the CAD model of the cowling surface to finite element (FE) representation, then its wind tunnel testing simulation at the different orientation of airflow to find the most stressed mode of flight. Numerical solutions of the Reynolds averaged Navier-Stokes (RANS) equations supplemented by k-w turbulence model provide the spatial distributions of air pressure applied to the shell surface. At the formulation of optimization problem the global strain energy calculated within the optimized shell was assumed as the objective. A wall thickness of the shell had to change over its surface to minimize the objective at the constrained weight. We used a parameterization of the problem that assumes an initiation of auxiliary sphere with varied radius and coordinates of the center, which were the design variables. Curve that formed by the intersection of the shell with sphere defined boundary of area, which should be reinforced by local thickening the shell wall. To eliminate a local stress concentration this increment was defined as the smooth function defined on the shell surface. As a result of structural optimization we obtained the thickness of shell's wall distribution, which then was used to design the draping and lay-up of composite prepreg layers. The global strain energy in the optimized cowling was reduced in2

  5. Study on calculation of rock pressure for ultra-shallow tunnel in poor surrounding rock and its tunneling procedure

    Institute of Scientific and Technical Information of China (English)

    Xiaojun Zhou; Jinghe Wang; Bentao Lin

    2014-01-01

    A computational method of rock pressure applied to an ultra-shallow tunnel is presented by key block theory, and its mathematical formula is proposed according to a mechanical tunnel model with super-shallow depth. Theoretical analysis shows that the tunnel is subject to asymmetric rock pressure due to oblique topography. The rock pressure applied to the tunnel crown and sidewall is closely related to the surrounding rock bulk density, tunnel size, depth and angle of oblique ground slope. The rock pressure applied to the tunnel crown is much greater than that to the sidewalls, and the load applied to the left side-wall is also greater than that to the right sidewall. Mean-while, the safety of the lining for an ultra-shallow tunnel in strata with inclined surface is affected by rock pressure and tunnel support parameters. Steel pipe grouting from ground surface is used to consolidate the unfavorable surrounding rock before tunnel excavation, and the reinforcing scope is proposed according to the analysis of the asymmetric load induced by tunnel excavation in weak rock with inclined ground surface. The tunneling procedure of bench cut method with pipe roof protection is still discussed and carried out in this paper according to the special geological condition. The method and tunneling procedure have been successfully utilized to design and drive a real expressway tunnel. The practice in building the super-shallow tunnel has proved the feasibility of the calculation method and tunneling procedure presented in this paper.

  6. Pressure Sores

    Science.gov (United States)

    ... injury. Some chronic diseases, such as diabetes and hardening of the arteries, make it hard for pressure ... Use a mild soap and warm (not hot) water. Apply moisturizers so your skin doesn’t get ...

  7. Fluid pressure arrival time tomography: Estimation and assessment in the presence of inequality constraints, with an application to a producing gas field at Krechba, Algeria

    Energy Technology Data Exchange (ETDEWEB)

    Rucci, A.; Vasco, D.W.; Novali, F.

    2010-04-01

    Deformation in the overburden proves useful in deducing spatial and temporal changes in the volume of a producing reservoir. Based upon these changes we estimate diffusive travel times associated with the transient flow due to production, and then, as the solution of a linear inverse problem, the effective permeability of the reservoir. An advantage an approach based upon travel times, as opposed to one based upon the amplitude of surface deformation, is that it is much less sensitive to the exact geomechanical properties of the reservoir and overburden. Inequalities constrain the inversion, under the assumption that the fluid production only results in pore volume decreases within the reservoir. We apply the formulation to satellite-based estimates of deformation in the material overlying a thin gas production zone at the Krechba field in Algeria. The peak displacement after three years of gas production is approximately 0.5 cm, overlying the eastern margin of the anticlinal structure defining the gas field. Using data from 15 irregularly-spaced images of range change, we calculate the diffusive travel times associated with the startup of a gas production well. The inequality constraints are incorporated into the estimates of model parameter resolution and covariance, improving the resolution by roughly 30 to 40%.

  8. Field test and research on vehicle load induced dynamic pore pressure in asphalt pavement%车载引起的沥青路面内动水压力现场试验研究

    Institute of Scientific and Technical Information of China (English)

    汤潍泽; 欧金秋; 崔新壮; 楼俊杰; 肖溟; 张炯; 黄丹; 侯飞

    2015-01-01

    In order to study the influence on moisture damage of asphalt pavement caused by dynamic pore pressure due to moving vehicle loads,and explore the time histories of dynamic stress and dynamic pore pressure in the pavement surface layers,the heat-resistant dynamic stress and pore pressure sensors were developed and used to measure the dynamic stresses and pore pressures in the field,and the field measured data of dynamic pore pressure was acquired. Based on the Biot’s consolidation theory,a numerical fluid-solid coupling simulation method reflecting mobile effect of wheel load was used to analyze the response of pavement under the actual condition.The time history of dynamic pore pressure in pavement was quantitatively analyzed.Numerical simulation results matched well with in situ test data.The pump-suction effect of dynamic pore pressure that continuously generated in pavement void under cyclical vehicle loads led to the reduce of the asphalt-aggregate bond strength and further triggered the moisture damage.This study verified the hydraulic drive mechanism of moisture damage,and provided a theoretical guild for the moisture damage research and pavement design.%为了研究移动车载引起的动水压力对沥青路面水损坏产生的影响,探究路面层内动应力变化及动水压力的长消规律,利用自主研制的耐高温动应力和动水压力传感器,对现场行车荷载引起的动应力及动水压力进行实测,获取了动水压力的实测数据;并且基于 Biot 固结理论,利用一种反映移动效应的车轮荷载数值模拟方法,对实测工况下路面情况进行了动态流固耦合分析,定量研究了路面层内的动水压力长消规律。发现现场实测与数值模拟结果基本一致。沥青路面在周期行车荷载作用下,路面空隙中不断产生动水压力的泵吸作用,导致沥青混合料强度下降,进而引发水损坏。该成果验证了水损坏的水力驱动机理,

  9. Simulation methodology for stochastic wind pressure field composed of gaussian and non-gaussian regions%高斯/非高斯混合随机风压场的模拟方法

    Institute of Scientific and Technical Information of China (English)

    罗俊杰; 苏成; 韩大建

    2012-01-01

    Simulation of stochastic fluctuating wind pressure field acting on roofs should meet the requirements of identity in statistical and spectral characteristics. The zero memory nonlinearity (ZMNL) transformation method was presented to generate the time histories of stochastic wind pressure. A detailed simulation procedure was provided, and two crucial problems were addressed. First, the standard covariance function for transforming multivariate non-Gaussian stochastic process vector into the corresponding Gaussian one was derived for simulating the stochastic wind pressure process following the lognormal distribution and the Weibull distribution. Second, a new method was proposed to cope with the problem of negative definite matrices of spectral density function appearing at certain frequencies while generating the Gaussian stochastic process vector. An illustrating example was given. It is shown that the proposed method can generate stochastic wind pressure field samples with the same specified statistical and spectral natures of the data obtained by wind tunnel experiment.%针对作用于屋盖结构随机风压场样本的统计特性要求,基于零记忆非线性转化法的理论,给出随机风压场的具体模拟过程.其中,解决了两个关键问题:①推导了服从对数正态分布和韦布尔分布的多点非高斯随机过程向量的标准化协方差,与相应高斯随机过程向量的标准化协方差的函数转化关系;②提出了分解谱密度函数修正法,解决利用谐波合成法模拟多点高斯随机过程向量时,功率谱密度函数矩阵在某些频率点出现负定的问题.经过具体算例表明,所提出的方法能生成合乎风洞实验数据统计特性要求的随机风压场样本.

  10. Low temperature-pressure batch experiments and field push-pull tests: Assessing potential effects of an unintended CO2 release from CCUS projects on groundwater chemistry

    Science.gov (United States)

    Mickler, P. J.; Yang, C.; Lu, J.; Reedy, R. C.; Scanlon, B. R.

    2012-12-01

    Carbon Capture Utilization and Storage projects (CCUS), where CO2 is captured at point sources such as power stations and compressed into a supercritical liquid for underground storage, has been proposed to reduce atmospheric CO2 and mitigate global climate change. Problems may arise from CO2 releases along discreet pathways such as abandoned wells and faults, upwards and into near surface groundwater. Migrating CO2 may inversely impact fresh water resources by increasing mineral solubility and dissolution rates and mobilizing harmful trace elements including As and Pb. This study addresses the impacts on fresh water resources through a combination of laboratory batch experiments, where aquifer sediment are reacted in their corresponding groundwater in 100% CO2 environments, and field push-pull tests where groundwater is equilibrated with 100% CO2, reacted in-situ in the groundwater system, and pulled out for analyses. Batch experiments were performed on aquifer material from carbonate dominated, mixed carbonate/silicalstic, and siliclastic dominated systems. A mixed silicalstic/carbonate system was chosen for the field based push-pull test. Batch experiment results suggest carbonate dissolution increased the concentration of Ca, Mg, Sr, Ba, Mn, U and HCO3- in groundwater. In systems with significant carbonate content, dissolution continued until carbonate saturation was achieved at approximately 1000 hr. Silicate dissolution increased the conc. of Si, K Ni and Co, but at much lower rates than carbonate dissolution. The elements As, Mo, V, Zn, Se and Cd generally show similar behavior where concentrations initially increase but soon drop to levels at or below the background concentrations (~48 hours). A Push-Pull test on one aquifer system produced similar geochemical behavior but observed reaction rates are higher in batch experiments relative to push-pull tests. Release of CO2 from CCUS sites into overlying aquifer systems may adversely impact groundwater quality

  11. A Study on Suction-rainfall Response of a Cut Slope in Unsaturated Residual Soil Using a Field Rain Simulator

    Directory of Open Access Journals (Sweden)

    Bujang B.K. Huat

    2005-01-01

    Full Text Available This research describes the design and construction of an artificial rain simulator system and the results obtained with regards to suction-rainfall response of a cut slope in unsaturated residual soil of weathered sandstone of various weathering grades. From the field measurements, the shallow tensiometers are found to record an immediate initial increase in matric suction within the first 20 min of the simulated rain before a gradual drop in suction takes place. However no such initial spikes in suction readings were recorded by the deeper tensiometers. With constant rainfall for the next 130 min, a clear drop in soil suction was observed in all cases illustrating the effect of net infiltration process. Positive pore water pressure was even recorded by some of the deeper tensiometers. The suction recorded by the shallow tensiometers was always higher than those of the deeper tensiometers, indicating a reduction in suction with depth below the ground surface. In term of weathering grades, residual soil of weathered sandstone of weathering grade III has the highest infiltration rate indicating the more porous nature of this soil material. Like wise there is a steeper drop in suction during the rain at the said location.

  12. Study on dynamics of the influence exerted by plasma on gas flow field in non-thermal atmospheric pressure plasma jet

    Science.gov (United States)

    Qaisrani, M. Hasnain; Xian, Yubin; Li, Congyun; Pei, Xuekai; Ghasemi, Maede; Lu, Xinpei

    2016-06-01

    In this paper, first, steady state of the plasma jet at different operating conditions is investigated through Schlieren photography with and without applying shielding gas. Second, the dynamic process for the plasma impacting on the gas flow field is studied. When the discharge is ignited, reduction in laminar flow occurs. However, when the gas flow rate is too low or too high, this phenomenon is not obvious. What is more, both frequency and voltage have significant impact on the effect of plasma on the gas flow, but the former is more significant. Shielding gas provides a curtain for plasma to propagate further. High speed camera along with Schlieren photography is utilized to study the impact of plasma on the gas flow when plasma is switched on and off. The transition of the gas flow from laminar to turbulent or vice versa happens right after the turbulent front. It is concluded that appearance and propagation of turbulence front is responsible for the transition of the flow state.

  13. Field Test and Evaluation of Engineered Biomineralization Technology for Sealing Existing Wells

    Energy Technology Data Exchange (ETDEWEB)

    Cunningham, Alfred [Montana State Univ., Bozeman, MT (United States)

    2015-12-21

    This research project addresses one of the goals of the U.S. Department of Energy (DOE) Carbon Storage Program (CSP) aimed at developing Advanced Wellbore Integrity Technologies to Ensure Permanent Geologic Carbon Storage. The technology field-tested in this research project is referred to as microbially induced calcite precipitation (MICP), which utilizes a biologically-based process to precipitate calcium carbonate. If properly controlled MICP can successfully seal fractures, high permeability zones, and compromised wellbore cement in the vicinity of wellbores and in nearby caprock, thereby improving the storage security of geologically-stored carbon dioxide. This report describes an MICP sealing field test performed on a 24.4 cm (9.625 inch) diameter well located on the Gorgas Steam Generation facility near Jasper, Alabama. The research was aimed at (1) developing methods for delivering MICP promoting fluids downhole using conventional oil field technologies and (2) assessing the ability of MICP to seal cement and formation fractures in the near wellbore region in a sandstone formation. Both objectives were accomplished successfully during a field test performed during the period April 1-11, 2014. The test resulted in complete biomineralization sealing of a horizontal fracture located 340.7 m (1118 feet) below ground surface. A total of 24 calcium injections and six microbial inoculation injections were required over a three day period in order to achieve complete sealing. The fractured region was considered completely sealed when it was no longer possible to inject fluids into the formation without exceeding the initial formation fracture pressure. The test was accomplished using conventional oil field technology including an 11.4 L (3.0 gallon) wireline dump bailer for injecting the biomineralization materials downhole. Metrics indicating successful MICP sealing included reduced injectivity during seal formation, reduction in pressure falloff, and

  14. The Design of High Pressure Filling Xe Ionization Chamber and Electric Field Simulation%高气压充 Xe 电离室的设计与电场模拟

    Institute of Scientific and Technical Information of China (English)

    付睿玺; 曾国强; 葛良全

    2015-01-01

    设计了一种阳极为平板型的高压充Xe共栅阳极电离室。根据电离室Xe气的压强与施加电场关系,确定最佳气体密度和电场强度。在理论上推导与分析的基础上,获得电离室输出信号和电场分布的关系,从而对探测器结构进行优化设计。通过ansoftmaxwell 12模拟电场实验,采用加入保护环、施加不同阴极和收集极电压的方法对电场等势线分布进行优化,改善电荷收集区和非电荷收集区分布,提高了电离室的能量分辨率。%This paper presents a high -voltage Xe filling grid anode ionization chamber which the anodes are flat type.The best of the gas density and the electric field strength is determined by comparing the pressure of Xe gas and the applied electric field .Through theoretical derivation and analysis the signal mechanism of the ioni -zation chamber using coplanar grid anode technology is obtained , getting the relationship between electric field distribution and the output signal of ionization chamber , so as to optimize the structure of the detector .Ansoft-maxwell 12 is used to simulate the electric field in the experiments .By adding a guard ring and applying differ-ent anode and cathode voltage to optimizing the equipotential lines , it plays the role of improving charge and non-charge collection region and improves the energy resolution of the Ionization chamber .

  15. A Model to Determine the Level of Serum Aldosterone in the Workers Attributed to the Combined Effects of Sound Pressure Level, Exposure Time and Serum Potassium Level: A Field-Based Study

    Directory of Open Access Journals (Sweden)

    Parvin Nassiri

    2016-09-01

    Full Text Available Background Occupational exposure to excessive noise is one of the biggest work-related challenges in the world. This phenomenon causes the release of stress-related hormones, which in turn, negatively affects cardiovascular risk factors. Objectives The current study study aimed to determine the level of workers’ serum aldosterone in light of the combined effect of sound pressure level, exposure time and serum potassium level. Methods This cross-sectional, descriptive, analytical study was conducted on 45 workers of Gol-Gohar Mining and Industrial Company in the fall of 2014. The subjects were divided into three groups (one control and two case groups, each including 15 workers. Participants in the control group were selected from workers with administrative jobs (exposure to the background noise. On the other hand, participants in the case groups were selected from the concentrator and pelletizing factories exposed to excessive noise. Serum aldosterone and potassium levels of participants were assessed at three different time intervals: at the beginning of the shift and before exposure to noise (7:30 - 8:00 AM, during exposure to noise (10:00 - 10:30 AM, and during continuous exposure (1:30 - 2:00 PM. The obtained data were transferred into SPSS ver. 18. Repeated measures analysis of variance (ANOVA was used to develop the statistical model of workers’ aldosterone level in light of the combined effect of sound pressure level, exposure time, and serum potassium level. Results The results of the final statistical model to determine the level of serum aldosterone based on the combined effect of sound pressure level, exposure time and serum potassium level indicated that the sound pressure level had a significant influence on the human’s serum aldosterone level (P = 0.04. In addition, the effects of exposure time and serum potassium on aldosterone level were statistically significant with P-values of 0.008 and 0.001, respectively. Conclusions

  16. Analysis of the Internal and External Flow Fields of High Pressure Water Jet Nozzle in Radial Drilling%径向钻井高压水射流喷嘴内外流场分析

    Institute of Scientific and Technical Information of China (English)

    易松林; 汪志明; 孙怡红; 易先中; 吉源强; 刘利军

    2013-01-01

    The technology of high pressure water jet in radial drilling has currently been used widely at home and abroad. A numerical simulation and analysis of the internal and external flow fields of jet nozzle will lay the foundation for the further study of selection of rational nozzle structure as well as for high pressure water jet rock breaking. According to the jet dynamic principle, the physical and mathematical models of axial - symmetrical submerged jet rock breaking with single nozzle were established. A numerical simulation of the internal and external flow fields of high pressure water jet nozzle in radial drilling was conducted with the Fluent software. The laws of the internal and external flow fields were analyzed in different jet distances and inlet flowrates. The analysis shows that there exist velocity attenuation, velocity retention in the cylindrical section and migration in the maximum speed. When the jet flow impacts into the radial hole bottom, the water cushion will occur on the bottomhole wall surface. This will produce a barrier to nozzle advance. Stagnation will arise in high pressure water jet for radial drilling. This will be unfavorable to the transportation of cuttings in the drilling process.%径向钻井高压水射流技术目前在国内外得到了广泛应用.对射流喷嘴内、外流场进行数值模拟分析将为选择合理的喷嘴结构以及为高压水射流破岩的进一步研究奠定基础.根据射流动力学原理,建立了单喷嘴轴对称淹没射流破岩的物理模型和数学模型,运用Fluent软件对径向钻井高压水射流喷嘴内、外流场进行了数值模拟,并分析了在不同喷距和入口流量下喷嘴内、外流场的规律.分析结果表明,射流轴线上存在速度衰减性、圆柱段速度保持性和最大速度偏移性;当射流冲击到径向井底后,在井底壁面上产生水垫,对喷头的推进产生阻碍作用;在径向钻井高压水射流中会产生滞止现象,

  17. Field project to obtain pressure core, wireline log, and production test data for evaluation of CO/sub 2/ flooding potential. Conoco MCA unit well No. 358, Maljamar Field, Lea County, New Mexico. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Swift, T.E.; Kumar, R.M.; Marlow, R.E.; Wilhelm, M.H.

    1982-08-01

    Field operations, which were conducted as a cooperative effort between Conoco and Gruy Federal, began on January 16, 1980 when the well was spudded. The well was drilled to 3692 feet, and 18 cores recovered in 18 core-barrel runs (144 feet). Upon completion of the coring phase, the hole was drilled to a total depth of 4150 feet and a complete suite of geophysical logs was run. Logging was then followed by completion and testing by Concoco. Core porosities agreed well with computed log porosities. Core water saturation and computed log porosities agree fairly well from 3692 to 3712 feet, poorly from 3712 to 3820 feet and in a general way from 4035 to 4107 feet. Computer log analysis techniques did not improve the agreement of log versus core derived water saturations. However, both core and log analysis indicated the ninth zone had the highest residual hydrocarbon saturations. Residual oil saturation were 259 STB/acre-ft for the 4035 - 4055 feet interval, and 150 STB/acre-ft for the 3692 - 3718 feet interval. Nine BOPD was produced from the 4035 - 4055 feet interval and no oil was produced from 3692 to 3718 feet interval, qualitatively confirming the relative oil saturations. The low oil production in the zone from 4022 to 4055 and the lack of production from 3692 to 3718 feet indicated the zone to be at or near residual waterflood conditions as determined by log analysis. 68 figures, 11 tables.

  18. Pressure transducer

    Science.gov (United States)

    Anderson, Thomas T.; Roop, Conard J.; Schmidt, Kenneth J.; Gunchin, Elmer R.

    1989-01-01

    A pressure transducer suitable for use in high temperature environments includes two pairs of induction coils, each pair being bifilarly wound together, and each pair of coils connected as opposite arms of a four arm circuit; an electrically conductive target moveably positioned between the coil pairs and connected to a diaphragm such that deflection of the diaphragm causes axial movement of the target and an unbalance in the bridge output.

  19. RELATIONSHIP AMONG EVAPORATION FLUX OF GROUNDWATER, DEPTH OF WATER TABLE AND NEGATIVE PRESSURE HEAD IN BARE SOIL

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Evaporation of ground water is a part of moisture circulation in the field.And it is a main natural form in which water transmits from the ground water to the soil water and atmosphere water.According to the simulated experiments, we study the relationship among the evaporation, depth of groundwater table and negative pressure.By theoretical analysis of the experimental results, the main conclusions are drawn as follows.There are two abrupt points in every Q-H curve.The locations of the abrupt points are separately in step with the height of top of the capillary fringe and the height of maximal capillary rise in the soil section.When the depth of ground water table H is small, the evaporation flux of ground water is large.While the depth of water table exceeds the maximal capillary rise of media in vadose zone, the capillary rise breaks up and evaporation flux of groundwater is small.The water content ratio in ground surface tends to be zero and the surface of soil tends to be drought.These conclusions show that the maximal capillary rise of media in vadose zone is an important value in regulating rational depth of ground water to reduce the evaporation of ground water and to increase effective quantity of water resources.In the meantime, these conclusions are of important theoretical and practical significance to reduce the evaporation of ground water, to prevent and cure the salinization of soil, and to make full use of and protect water resources in the northern plains in China.

  20. Pressure Ulcer Prevention

    Science.gov (United States)

    2009-01-01

    Executive Summary In April 2008, the Medical Advisory Secretariat began an evidence-based review of the literature concerning pressure ulcers. Please visit the Medical Advisory Secretariat Web site, http://www.health.gov.on.ca/english/providers/program/mas/tech/tech_mn.html to review these titles that are currently available within the Pressure Ulcers series. Pressure ulcer prevention: an evidence based analysis The cost-effectiveness of prevention strategies for pressure ulcers in long-term care homes in Ontario: projections of the Ontario Pressure Ulcer Model (field evaluation) Management of chronic pressure ulcers: an evidence-based analysis (anticipated pubicstion date - mid-2009) Purpose A pressure ulcer, also known as a pressure sore, decubitus ulcer, or bedsore, is defined as a localized injury to the skin/and or underlying tissue occurring most often over a bony prominence and caused by pressure, shear, or friction, alone or in combination. (1) Those at risk for developing pressure ulcers include the elderly and critically ill as well as persons with neurological impairments and those who suffer conditions associated with immobility. Pressure ulcers are graded or staged with a 4-point classification system denoting severity. Stage I represents the beginnings of a pressure ulcer and stage IV, the severest grade, consists of full thickness tissue loss with exposed bone, tendon, and or muscle. (1) In a 2004 survey of Canadian health care settings, Woodbury and Houghton (2) estimated that the prevalence of pressure ulcers at a stage 1 or greater in Ontario ranged between 13.1% and 53% with nonacute health care settings having the highest prevalence rate (Table 1). Executive Summary Table 1: Prevalence of Pressure Ulcers* Setting Canadian Prevalence,% (95% CI) Ontario Prevalence,Range % (n) Acute care 25 (23.8–26.3) 23.9–29.7 (3418) Nonacute care† 30 (29.3–31.4) 30.0–53.3 (1165) Community care 15 (13.4–16.8) 13.2 (91) Mixed health care‡ 22 (20.9

  1. Blood pressure measurement

    Science.gov (United States)

    Diastolic blood pressure; Systolic blood pressure; Blood pressure reading; Measuring blood pressure ... or your health care provider will wrap the blood pressure cuff snugly around your upper arm. The lower ...

  2. High-pressure and pulsed electric field

    DEFF Research Database (Denmark)

    Olsen, Nina Veflen; Sonne, Anne-Mette

    2010-01-01

    New products and new processing techniques are continuously developed within the food industry. While food scientists may focus on the technical novelty and applaud the progress of science, consumers are often conservative and skeptical towards changes. As learned from earlier experiences with ge...

  3. Effect on DNA Methylation of Guodao 6 by Strong Electric Field Radiation at Atmospheric Pressure%常压下强电场辐射对国稻6号DNA甲基化的影响

    Institute of Scientific and Technical Information of China (English)

    熊建平; 何平; 黎兆东; 刘利民; 谢腾飞; 疏冕

    2013-01-01

    目的:研究常压下强电场辐射对国稻6号DNA甲基化的影响.方法:常压下在相同时间下,以不同强度(和在相同强度下,以不同时间)辐射国稻6号种子,应用甲基化敏感扩增多态性(methylation sensitive amplification polymorphism,MSAP)技术,研究在不同辐射条件下,水稻基因组DNA甲基化的水平及差异.结果:所有强电场辐射的试验组甲基化水平都比未辐射的对照组有所降低,并与辐射的时间和强度有关.细胞DNA全甲基化、半甲基化扩增位点占总扩增位点的比例为:12.89%~13.62%,3.36%~4.63%,随着辐射强度和时间的增加有所降低.结论:说明经强电场辐射的国稻6号水稻基因组DNA甲基化较亲本发生了明显的变异,强电场能引起表观遗传变异,为研究其规律奠定了基础,也为探讨水稻甲基化对水稻生长调控的分子机理提供了帮助.%Objective: The strong electric field radiation under atmospheric pressure to the rice 6 the influence of DNA methylation. Methods: Under atmospheric pressure at the same time, based on the different strength (and in the same strength, in different time) radiation Guodao 6 seed, the application of DNA methylation sensitive amplification polymorphism (methylation sensitive amplification polymorphism, MSAP) technology, the research in different radiation condition, the rice genome DNA methylation level and difference. Results: All the strong electric field radiation treatment group methylation level than the control group did not radiation reduced, and radiation time and strength about. All cell DNA methylation, half methylation amplification sites accounted for the proportion of amplification sites for: 12.89% ~ 13.62%, 3.36% ~ 4.63%, with the increase of radiation intensity and time reduced. Conclusions: The strong electric field radiation kingdom rice 6 rice genome DNA methylation is parent changed obviously variation that strong electric field can cause apparent

  4. Neutron scattering techniques for betaine calcium chloride dihydrate under applied external field (temperature, electric field and hydrostatic pressure); Etude par diffusion de neutrons du chlorure de calcium et de betaine dihydrate sous champ externe applique (temperature, champ electrique et pression hydrostatique)

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez, O

    1997-11-17

    We have studied with neutron scattering techniques betaine calcium chloride dihydrate (BCCD), a dielectric aperiodic crystal which displays a Devil`s staircase type phase diagram made up of several incommensurate and commensurate phases, having a range of stability very sensitive to temperature, electric field and hydrostatic pressure. We have measured a global hysteresis of {delta}(T) of about 2-3 K in the two incommensurate phases. A structural study of the modulated commensurate phases 1/4 and 1/5 allows us to evidence that the atomic modulation functions are anharmonic. The relevance of the modelization of the modulated structure by polar Ising pseudo-spins is then directly established. On the basis of group theory calculation in the four dimensional super-space, we interpret this anharmonic modulation as a soliton regime with respect to the lowest-temperature non modulated ferroelectric phase. The continuous character of the transition to the lowest-temperature non modulated phase and the diffuse scattering observed in this phase are accounted for the presence of ferroelectric domains separated by discommensurations. Furthermore, we have shown that X-rays induce in BCCD a strong variation with time of irradiation of the intensity of satellite peaks, and more specifically for third order ones. This is why the `X-rays` structural model is found more harmonic than the `neutron` one. Under electric field applied along the vector b axis, we confirm that commensurate phases with {delta} = even/odd are favoured and hence are polar along this direction. We have evidenced at 10 kV / cm two new higher order commensurate phases in the phase INC2, corroborating the idea of a `complete` Devil`s air-case phase diagram. A phenomenon of generalized coexistence of phases occurs above 5 kV / cm. We have characterized at high field phase transitions between `coexisting` phases, which are distinguishable from classical lock-in transitions. Under hydrostatic pressure, our results

  5. High pressure rinsing parameters measurements

    Energy Technology Data Exchange (ETDEWEB)

    Cavaliere, E. [INFN Milano - LASA, Via F.lli Cervi 201, I-20090 Segrate (MI) (Italy); Fusetti, M. [INFN Milano - LASA, Via F.lli Cervi 201, I-20090 Segrate (MI) (Italy); Michelato, P. [INFN Milano - LASA, Via F.lli Cervi 201, I-20090 Segrate (MI) (Italy); Pagani, C. [INFN Milano - LASA, Via F.lli Cervi 201, I-20090 Segrate (MI) (Italy)]. E-mail: carlo.pagani@mi.infn.it; Pierini, P. [INFN Milano - LASA, Via F.lli Cervi 201, I-20090 Segrate (MI) (Italy); Paulon, R. [INFN Milano - LASA, Via F.lli Cervi 201, I-20090 Segrate (MI) (Italy); Sertore, D. [INFN Milano - LASA, Via F.lli Cervi 201, I-20090 Segrate (MI) (Italy)

    2006-07-15

    High pressure rinsing with ultra pure water jet is an essential step in the high field superconducting cavity production process. In this paper, we illustrate the experimental characterization of a HPR system, in terms of specific power and energy deposition on the cavity surfaces and on the damage threshold for niobium. These measurements are used to tentatively derive general rules for the optimization of the free process parameters (nozzle geometry, speeds and water pressure)

  6. [Development of an automatic pneumatic tourniquet system that determines pressures in synchrony with systolic blood pressure].

    Science.gov (United States)

    Liu, Hongyun; Li, Kaiyuan; Zhang, Zhengbo; Guo, Junyan; Wang, Weidong

    2012-11-01

    The correlation coefficients between arterial occlusion pressure and systolic blood pressure, diastolic blood pressure, limb circumference, body mass etc were obtained through healthy volunteer experiments, in which tourniquet were applied on upper/lower extremities. The prediction equations were derived from the data of experiments by multiple regression analysis. Based on the microprocessor C8051F340, a new pneumatic tourniquet system that can determine tourniquet pressure in synchrony with systolic blood pressure was developed and verified the function and stability of designed system. Results showed that the pneumatic tourniquet which automatically adjusts occlusion pressure in accordance with systolic blood pressure could stop the flow of blood to get a bloodless field.

  7. Effect of current on the microstructure and performance of (Bi2Te3)0.2(Sb2Te3)0.8 thermoelectric material via field activated and pressure assisted sintering

    Institute of Scientific and Technical Information of China (English)

    Chen Ruixue; Meng Qingsen; Fan Wenhao; Wang Zhong

    2011-01-01

    (Bi2Te3)0.2(Sb2Te3)0.8 thermoelectric material was sintered via a field activated and pressure assisted sintering (FAPAS) process.By applying different current intensity (0,60,320 A/cm2) in the sintering process,the effects of electric current on the microstructure and thermoelectric performance were investigated.This demonstrated that the application of electric current in the sintering process could significantly improve the uniformity and density of(Bi2Te3)0.2(Sb2Te3)0.8 samples.When the current intensity was raised to 320 A/cm2,the preferred orientation of grains was observed.Moreover,positive effects on the thermoelectric performance of applying electric current in the sintering process were also confirmed.An increase of 0.02 and 0.11 in the maximum figure of merit ZT value could be acquired by applying current of 60 and 320 A/cm2,respectively.

  8. Study on Anomaly Recognition of Pressure Monitoring Data of Gathering System in Gas Field%天然气气田集输系统压力监测数据异常值识别研究

    Institute of Scientific and Technical Information of China (English)

    同晓侠; 徐春野; 尚凡坤; 杨毅; 覃明友

    2015-01-01

    The accurate identification of abnormal value of monitoring data in gas gathering system is of great significance for the safe and efficient operation of the system .Based on support vector regression algorithm and regarding monitoring data of a gas field gathering system as the case ,the anomaly recognition method of pressure monitoring data is constructed .The characteristics of monitoring values is judged by calculating the difference between the return value and measured value in order to avoid the safety control system malfunction .Engineering verification shows that the recognition method is superior . The work done can provide scientific references for the optimization of transportation monitoring system .%气田集输系统监测压力数据异常值的准确识别对于系统的安全高效运行具有重要意义。基于支持向量回归机算法,以某气田集输系统监测数据为例,构建了集输系统压力监测数据异常识别方法,工程验证表明所构建的识别方法具有较强的优越性及参考价值。

  9. Numerical Simulation and Analysis of Downstream Flow Field of Low-Pressure Swirl Nozzle Based on Fluent%基于Fluent低压旋流喷嘴下游流场数值模拟及分析

    Institute of Scientific and Technical Information of China (English)

    董星涛; 李超; 朱健; 付方凯; 洪张舟

    2012-01-01

    The paper simulated the downstream flow field atomization situation of low-pressure swirl nozzle by using Fluent software. The Euler-Lagrangian models were applied to simulate gas-liquid two phase coupled flow. And the simulation results show that when atomizing liquid spray with hollow cone shape accords with experimental results. The droplet velocity ranged from 15m/s to 25m/s decreases with the spray particle diameter increases; however, diameter of the spray droplet will be increased with the increasing of axial distance along the axle. [ Ch,7 fig. 9 ref. ]%运用Fluent软件模拟了低压旋流喷嘴下游流场喷雾情况.利用欧拉-拉格朗日模型模拟气液两相耦合流动.模拟显示:喷嘴喷雾形状为空心锥状,与实验得到的喷雾形状相符.喷雾的液滴速度分布于15~ 25 m/s之间,且随轴向距离的增大而减小;喷雾的液滴直径沿轴向距离增大而增大.

  10. Lava lake level as a gauge of magma reservoir pressure and eruptive hazard

    Science.gov (United States)

    Patrick, Matthew R.; Anderson, Kyle R.; Poland, Michael P.; Orr, Tim R.; Swanson, Donald A.

    2015-01-01

    Forecasting volcanic activity relies fundamentally on tracking magma pressure through the use of proxies, such as ground surface deformation and earthquake rates. Lava lakes at open-vent basaltic volcanoes provide a window into the uppermost magma system for gauging reservoir pressure changes more directly. At Kīlauea Volcano (Hawaiʻi, USA) the surface height of the summit lava lake in Halemaʻumaʻu Crater fluctuates with surface deformation over short (hours to days) and long (weeks to months) time scales. This correlation implies that the lake behaves as a simple piezometer of the subsurface magma reservoir. Changes in lava level and summit deformation scale with (and shortly precede) changes in eruption rate from Kīlauea's East Rift Zone, indicating that summit lava level can be used for short-term forecasting of rift zone activity and associated hazards at Kīlauea.

  11. 徐深气田盖储压力配置类型与天然气聚集%The Relation between Pressure Matching Types of Accumulation Gas Ability and Loss Gas Ability and Reserves Abundance in Xushen Gas Field

    Institute of Scientific and Technical Information of China (English)

    于有; 付广; 郭杜军

    2011-01-01

    通过气藏盖层排替压力与储层剩余压力特征研究,对徐深气田盖储压力配置类型及与储量丰度关系进行了研究,得到盖高储低压力配置类型最有利于天然气富集,其次是盖高储低压力配置类型和较强聚弱散配置类型,徐深气田19个气藏盖储压力配置类型有5种,以盖高储较高压力配置类型最多,盖高储中压力配置类型次之.徐深气田19个气藏以中等储量丰度的气藏个数最多,高、低储量丰度的气藏个数相对较少.盖高储中压力配置和盖较高储中压力配置类型是徐深气田形成高储量丰度气藏的主要盖储压力配置类型.%By the study of characteristics of displacement pressure of caprocks and remaining pressures of reservoirs, the relation between matching types of accumulation gas ability and loss gas ability and reserves abundance are studied. Matching types of the best accumulation gas ability and the bad loss gas ability are considered to be favorable for gas to accumulate. The second are matching types of the best accumulation gas ability and the medium loss gas ability and matching types of the better accumulation gas ability and the bad loss gas ability. It is considered that there are 5 matching types of accumulation gas ability and loss gas ability of 19 gas reservoirs in Xushen gas field. The most is matching types of the best accumulation gas ability and the better loss gas ability. The second is matching types of the best accumulation gas ability and the medium loss gas ability. It was considered that among the 19 gas reservoirs in Xushen gas field, those with middle gas reserves abundance were considered to be the most.The second are those gas reservoirs with high and lower gas reserves abundance. Matching types of the best accumulation gas ability and the medium loss gas ability and matching type of better accumulation gas ability and medium loss gas ability is considered to be the best matching types of accumulation

  12. Study of far-field pressure wavelet of air-gun bubble based on p otential flow theory%基于势流理论的气枪气泡远场压力子波特性研究

    Institute of Scientific and Technical Information of China (English)

    叶亚龙; 李艳青; 张阿漫

    2014-01-01

    The study of far-field pressure wavelet of air-gun bubble is the basic research of air-gun sources. In this paper, a boundary element bubble model is established to simulate the dynamics of bubble, and an energy equivalent method is put forward to solve the bottleneck of bubble jet. In our simplified model, the bubble model takes into consideration the thermodynamic factors such as heat transfer and gas release, and the numerical results agree with the data of Nucleus software well. Based on the established model, the influence of heat transfer coefficient, air-gun firing time, and specific heat at constant volume on the pressure wavelet are studied. Finally, the three-dimensional bubble merging numerical method is put forward, which is an expansion of the axisymmetric model. Thus, the preliminary study of coherent air-gun is conducted, especially the influence of the space between two bubbles on the wavelet. This paper provides a reference for the research of air-gun.%气枪气泡的远场压力子波特性研究是研究气枪震源的基础,本文在前人研究基础上建立了三维边界元气泡动力学模型,并针对气泡射流这一技术瓶颈提出了能量等效算法。再在上述模型中加入了简化的热力学模型,考虑了气枪释放气体以及气泡传热等热力学因素,将上面模型计算结果和Nucleus软件模拟结果对比,两者符合良好,并以此为基础探讨了传热系数、气枪发射时间、气体等体比热容对气枪主要参数的影响规律。最后将轴对称气泡融合技术拓展到三维边界元模型,对相干枪进行初步研究,探讨了气枪间距对压力子波的影响规律,旨在为气枪的研究提供参考。

  13. Low Blood Pressure

    Science.gov (United States)

    ... a problem. Sometimes blood pressure that is too low can also cause problems. Blood pressure is the ... reading is 90/60 or lower, you have low blood pressure. Some people have low blood pressure ...

  14. Normal Pressure Hydrocephalus (NPH)

    Science.gov (United States)

    ... your local chapter Join our online community Normal Pressure Hydrocephalus (NPH) Normal pressure hydrocephalus is a brain ... About Symptoms Diagnosis Causes & risks Treatments About Normal Pressure Hydrocephalus Normal pressure hydrocephalus occurs when excess cerebrospinal ...

  15. Hypertension (High Blood Pressure)

    Science.gov (United States)

    ... Surgery? A Week of Healthy Breakfasts Shyness Hypertension (High Blood Pressure) KidsHealth > For Teens > Hypertension (High Blood Pressure) Print ... rest temperature diet emotions posture medicines Why Is High Blood Pressure Bad? High blood pressure means a person's heart ...

  16. Investigation of the flow-field of two parallel round jets impinging normal to a flat surface

    Science.gov (United States)

    Myers, Leighton M.

    The flow-field features of dual jet impingement were investigated through sub-scale model experiments. The experiments were designed to simulate the environment of a Short Takeoff, and Vertical Landing, STOVL, aircraft performing a hover over the ground, at different heights. Two different dual impinging jet models were designed, fabricated, and tested. The Generation 1 Model consisted of two stainless-steel nozzles, in a tandem configuration, each with an exit diameter of approximately 12.7 mm. The front convergent nozzle was operated at the sonic Mach number of 1.0, while the rear C-D nozzle was generally operated supersonically. The nozzles were embedded in a rectangular flat plate, referred to as the lift plate, which represents a generic lifting surface. The lift plate was instrumented with 36 surface pressure taps, which were used to examine the flow entrainment and recirculation patterns caused by varying the stand-off distance from the nozzle exits to a flat ground surface. The stand-off distance was adjusted with a sliding rail frame that the ground plane was mounted to. Typical dimensionless stand-off distances (ground plane separation) were H/DR = 2 to 24. A series of measurements were performed with the Generation 1 model, in the Penn State High Speed Jet Aeroacoustics Laboratory, to characterize the basic flow phenomena associated with dual jet impingement. The regions of interest in the flow-field included the vertical jet plume(s), near impingement/turning region, and wall jet outwash. Other aspects of interest included the loss of lift (suckdown) that occurs as the ground plane separation distance becomes small, and azimuthal variation of the acoustic noise radiation. Various experimental methods and techniques were used to characterize the flow-field, including flow-visualization, pressure rake surveys, surface mounted pressure taps, laser Doppler velocimetry, and acoustic microphone arrays. A second dual impinging jet scale model, Generation 2

  17. Turbine exhaust pressure measurements

    Energy Technology Data Exchange (ETDEWEB)

    Burns, J.M. [Stone & Webster Engineering Corp., Boston, MA (United States); Hernandez, E. [Community Energy Alternatives Inc., Ridgewood, NJ (United States)

    1996-05-01

    This paper discusses the dynamic operating environment in the turbine-condenser steam space and the two sensors, basket tips and guideplates, that have been approved by ASME test codes for measurement of the static pressure within that exhaust region. It defines the rigorous geometry and construction requirements of these sensors in order that they be acceptable for guarantee/acceptance testing. The paper also offers a practical alternative to the classical ASME PTC 6 (Turbine Test Code) basket tip design that is easier to fabricate in the typical utility machine shop. The alternative design makes it less expensive, much faster to construct, and facilitates the drainage of any accumulated condensate. Comparative field tests by PSE&G`s Research and Testing Laboratory conducted in 1995 at the 300 MW Mercer Generating Station, Unit 1 will be described which demonstrate the modified basket tip pressure measurements are statistically indistinguishable from those of the PTC 6 design. Noting that basket tip turbine exhaust static pressure sensors are recommended by all the major U.S. turbine manufacturers, the paper also presents the limited available history of the empirical basket tip and the lack of any documented calibration history related to the accuracy of the guideplate. Finally, based on the success of this one basket tip variation, the paper concludes that other even more suitable designs could be developed by further research.

  18. Chromium at High Pressure

    Science.gov (United States)

    Jaramillo, Rafael

    2012-02-01

    Chromium has long served as the archetype of spin density wave magnetism. Recently, Jaramillo and collaborators have shown that Cr also serves as an archetype of magnetic quantum criticality. Using a combination of x-ray diffraction and electrical transport measurements at high pressures and cryogenic temperatures in a diamond anvil cell, they have demonstrated that the N'eel transition (TN) can be continuously suppressed to zero, with no sign of a concurrent structural transition. The order parameter undergoes a broad regime of exponential suppression, consistent with the weak coupling paradigm, before deviating from a BCS-like ground state within a narrow but accessible quantum critical regime. The quantum criticality is characterized by mean field scaling of TN and non mean field scaling of the transport coefficients, which points to a fluctuation-induced reconstruction of the critical Fermi surface. A comparison between pressure and chemical doping as means to suppress TN sheds light on different routes to the quantum critical point and the relevance of Fermi surface nesting and disorder at this quantum phase transition. The work by Jaramillo et al. is broadly relevant to the study of magnetic quantum criticality in a physically pure and theoretically tractable system that balances elements of weak and strong coupling. [4pt] [1] R. Jaramillo, Y. Feng, J. Wang & T. F. Rosenbaum. Signatures of quantum criticality in pure Cr at high pressure. Proc. Natl. Acad. Sci. USA 107, 13631 (2010). [0pt] [2] R. Jaramillo, Y. Feng, J. C. Lang, Z. Islam, G. Srajer, P. B. Littlewood, D. B. McWhan & T. F. Rosenbaum. Breakdown of the Bardeen-Cooper-Schrieffer ground state at a quantum phase transition. Nature 459, 405 (2009).

  19. Low-pressure

    Energy Technology Data Exchange (ETDEWEB)

    Baker, Richard [Membrane Technology And Research, Inc., Newark, CA (United States); Kniep, Jay [Membrane Technology And Research, Inc., Newark, CA (United States); Hao, Pingjiao [Membrane Technology And Research, Inc., Newark, CA (United States); Chan, Chi Cheng [Membrane Technology And Research, Inc., Newark, CA (United States); Nguyen, Vincent [Membrane Technology And Research, Inc., Newark, CA (United States); Huang, Ivy [Membrane Technology And Research, Inc., Newark, CA (United States); Amo, Karl [Membrane Technology And Research, Inc., Newark, CA (United States); Freeman, Brice [Membrane Technology And Research, Inc., Newark, CA (United States); Fulton, Don [Membrane Technology And Research, Inc., Newark, CA (United States); Ly, Jennifer [Membrane Technology And Research, Inc., Newark, CA (United States); Lipscomb, Glenn [Membrane Technology And Research, Inc., Newark, CA (United States); Lou, Yuecun [Membrane Technology And Research, Inc., Newark, CA (United States); Gogar, Ravikumar [Membrane Technology And Research, Inc., Newark, CA (United States)

    2015-01-29

    This final technical progress report describes work conducted by Membrane Technology and Research, Inc. (MTR) for the Department of Energy (DOE NETL) on development of low-pressure membrane contactors for carbon dioxide (CO2) capture from power plant flue gas (award number DE-FE0007553). The work was conducted from October 1, 2011 through September 30, 2014. The overall goal of this three-year project was to build and operate a prototype 500 m2 low-pressure sweep membrane module specifically designed to separate CO2 from coal-fired power plant flue gas. MTR was assisted in this project by a research group at the University of Toledo, which contributed to the computational fluid dynamics (CFD) analysis of module design and process simulation. This report details the work conducted to develop a new type of membrane contactor specifically designed for the high-gas-flow, low-pressure, countercurrent sweep operation required for affordable membrane-based CO2 capture at coal power plants. Work for this project included module development and testing, design and assembly of a large membrane module test unit at MTR, CFD comparative analysis of cross-flow, countercurrent, and novel partial-countercurrent sweep membrane module designs, CFD analysis of membrane spacers, design and fabrication of a 500 m2 membrane module skid for field tests, a detailed performance and cost analysis of the MTR CO2 capture process with low-pressure sweep modules, and a process design analysis of a membrane-hybrid separation process for CO2 removal from coal-fired flue gas. Key results for each major task are discussed in the report.

  20. Impingement of a radial jet with an annular jet. 3rd Report. Curved properties of main jet with pressure field; Hoshajo funryu to kanjo funryu no shototsu ni kansuru kenkyu. 3. Atsuryokuba ni yoru shufunryu no wankyoku tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, T.; Kozato, Y.; Tanaka, E. [Gifu University, Gifu (Japan). Faculty of Engineering; Kariya, M. [Meidensha Corp., Tokyo (Japan)

    1994-12-25

    Annular jets (control flows) flowing out from a columnar nozzle and a concentrically circular annular nozzle were impinged perpendicularly to a main jet flowing radially from the columnar nozzle. Then, an investigation was given on pressure in a recirculation flow region, bending of the main jet, and reattachment characteristics of the main jet onto a side wall face when the deflection of the main jet and its reattachment phenomenon onto the side wall face are controlled. The experiment was performed under the conditions of a nozzle width of 6 mm, an inter-nozzle distance of 4, a control flow rate (a ratio of a flow-out rate of the control flow to that of the main jet) from 0 to 0.6, with the step height varied. Investigations were made on change of static pressure distribution in jets in the downstream direction, change of static pressure on the side wall face in the downstream direction, and the relationship between the reattachment position on the side wall and the average static pressure in the recirculation flow region. The relationship of the reattachment position of the main jet on the side wall with the average side wall static pressure and the average static pressure in the recirculation flow region is expressed by one curve. The reattachment position gets closer to the nozzle outlet as the pressure decreases in the recirculation flow region. 9 refs., 14 figs., 1 tab.

  1. Noise Evaluation Technique Based on Surface Pressure

    DEFF Research Database (Denmark)

    Fischer, Andreas

    2012-01-01

    In this chapter the relevant theory for the understanding of TE noise modeling is collected. It contains the acoustic formulations of [31] and [57]. Both give a relation for the far field sound pressure in dependence of the frequency wave number spectral density of the pressure on the airfoil...

  2. Foot Plantar Pressure Measurement System: A Review

    Directory of Open Access Journals (Sweden)

    Yufridin Wahab

    2012-07-01

    Full Text Available Foot plantar pressure is the pressure field that acts between the foot and the support surface during everyday locomotor activities. Information derived from such pressure measures is important in gait and posture research for diagnosing lower limb problems, footwear design, sport biomechanics, injury prevention and other applications. This paper reviews foot plantar sensors characteristics as reported in the literature in addition to foot plantar pressure measurement systems applied to a variety of research problems. Strengths and limitations of current systems are discussed and a wireless foot plantar pressure system is proposed suitable for measuring high pressure distributions under the foot with high accuracy and reliability. The novel system is based on highly linear pressure sensors with no hysteresis.

  3. Blood Pressure Test

    Science.gov (United States)

    ... an online personal health record or blood pressure tracker, for example. This gives you the option of ... lower your blood pressure. Exercise regularly. Regular physical activity can help lower your blood pressure and keep ...

  4. Low Blood Pressure (Hypotension)

    Science.gov (United States)

    ... and rises sharply on waking. Blood pressure: How low can you go? What's considered low blood pressure ... even life-threatening disorders. Conditions that can cause low blood pressure Some medical conditions can cause low ...

  5. Preventing pressure ulcers

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/patientinstructions/000147.htm Preventing pressure ulcers To use the sharing features on this page, please enable JavaScript. Pressure ulcers are also called bedsores, or pressure sores. They ...

  6. Dealing with Peer Pressure

    Science.gov (United States)

    ... Lifesaver Kids Talk About: Coaches Dealing With Peer Pressure KidsHealth > For Kids > Dealing With Peer Pressure Print ... talk about how to handle it. Defining Peer Pressure Peers influence your life, even if you don' ...

  7. Intracranial pressure monitoring

    Science.gov (United States)

    ICP monitoring; CSF pressure monitoring ... There are 3 ways to monitor pressure in the skull (intracranial pressure). INTRAVENTRICULAR CATHETER The intraventricular catheter is the most accurate monitoring method. To insert an intraventricular catheter, a ...

  8. High Blood Pressure

    Science.gov (United States)

    ... normal blood pressure 140/90 or higher is high blood pressure Between 120 and 139 for the top number, ... prehypertension. Prehypertension means you may end up with high blood pressure, unless you take steps to prevent it. High ...

  9. High Blood Pressure (Hypertension)

    Science.gov (United States)

    ... Print Page Text Size: A A A Listen High Blood Pressure (Hypertension) Nearly 1 in 3 American adults has ... weight. How Will I Know if I Have High Blood Pressure? High blood pressure is a silent problem — you ...

  10. Low Blood Pressure (Hypotension)

    Science.gov (United States)

    Low blood pressure (hypotension) Overview By Mayo Clinic Staff Low blood pressure might seem desirable, and for some people, it causes no problems. However, for many people, abnormally low blood pressure (hypotension) can cause dizziness and fainting. In severe ...

  11. [Prevention of pressure ulcer (bedsore)].

    Science.gov (United States)

    Sedmak, Dijana; Vrhovec, Marina; Huljev, Dubravko

    2013-10-01

    Although progress in many fields of science, medicine and technology is evident, we are still witnessing the appearance of bedsores and its consequences. However, in the last fifty years there has been considerable progress in the understanding of its causes, prevention and treatment. Prevention and treatment of pressure ulcers are complicated by the many misconceptions. However, with due knowledge of the process of healing of acute and chronic wounds and of the pathophysiological processes, in many cases chronic wounds, like pressure ulcers, can now be prevented and cured, and thus reduce the cost of treatment, as well as the mortality rate.

  12. Limit analysis of supporting pressure in tunnels with regard to surface settlement

    Institute of Scientific and Technical Information of China (English)

    杨小礼; 覃长兵

    2015-01-01

    The proliferation of Hoek-Brown nonlinear failure criterion and upper bound theorem makes it possible to evaluate the stability of circular tunnels with an original curved collapsing mechanism. The arch effect of shallow circle tunnel is not taken into consideration so that the mechanical characteristics can be easily described. Based on the mechanism, the upper bound solution of supporting pressure of tunnels under the condition of surface settlements and overloads on the ground surface is derived. The objective function is formed from virtual work equations under the variational principle, and solutions are presented by the optimum theory. Comparisons with previous works are made. The numerical results of the present method show great agreement with those of existing ones. With regard to the surface settlement and overloads, the influence of different rock parameters on the collapsing shape is analyzed.

  13. Study of the unknown HONO daytime source at an European suburban site during the MEGAPOLI summer and w