Science.gov

Sample records for 2-year field investigation

  1. Artificial-recharge investigation near Aurora, Nebraska: 2-year progress report

    USGS Publications Warehouse

    Lichtler, William F.; Stannard, David I.; Kouma, Edwin

    1979-01-01

    This report presents the results of the first 2 years of a 4-year investigation of potential for artificial recharge and recharge methods that might be used to mitigate excessive aquifer depletion in Nebraska. A Quaternary sand-and-gravel aquifer near Aurora, Nebr., was recharged by injecting water through a well at a rate of approximately 730 gallons per minute for nearly 6 months. Total recharge was 530 acre-feet. Recharge was intermittent during the first 2 months, but was virtually continuous during the last 4 months. Buildup of the water level in the recharge well was 17 feet. The rate of buildup indicates that the well could have accepted water by gravity flow at more than 3,000 gallons per minute for at least 1 year. The cause of a continuing slow rise in water levels in the recharge well in contrast to nearly stable water levels in observation wells as close as 10 feet from the recharge well is as yet uncertain. The recharge water and the native ground water appeared to be chemically compatible. Infiltration rates from 24-foot-diameter surface impoundments ranged from 0.04 to 0.66 feet per day. The higher rates may have resulted in part from leakage down incompletely sealed holes that were drilled to install monitoring equipment. The investigation, including a report on the entire project, is scheduled for completion by 1980.

  2. Cognitive and Linguistic Sources of Variance in 2-Year-Olds' Speech-Sound Discrimination: A Preliminary Investigation

    ERIC Educational Resources Information Center

    Lalonde, Kaylah; Holt, Rachael Frush

    2014-01-01

    Purpose: This preliminary investigation explored potential cognitive and linguistic sources of variance in 2- year-olds' speech-sound discrimination by using the toddler change/no-change procedure and examined whether modifications would result in a procedure that can be used consistently with younger 2-year-olds. Method: Twenty typically…

  3. Ground vortex flow field investigation

    NASA Technical Reports Server (NTRS)

    Kuhn, Richard E.; Delfrate, John H.; Eshleman, James E.

    1988-01-01

    Flow field investigations were conducted at the NASA Ames-Dryden Flow Visualization Facility (water tunnel) to investigate the ground effect produced by the impingement of jets from aircraft nozzles on a ground board in a STOL operation. Effects on the overall flow field with both a stationary and a moving ground board were photographed and compared with similar data found in other references. Nozzle jet impingement angles, nozzle and inlet interaction, side-by-side nozzles, nozzles in tandem, and nozzles and inlets mounted on a flat plate model were investigated. Results show that the wall jet that generates the ground effect is unsteady and the boundary between the ground vortex flow field and the free-stream flow is unsteady. Additionally, the forward projection of the ground vortex flow field with a moving ground board is one-third less than that measured over a fixed ground board. Results also showed that inlets did not alter the ground vortex flow field.

  4. The MAVEN Magnetic Field Investigation

    NASA Astrophysics Data System (ADS)

    Connerney, J. E. P.; Espley, J.; Lawton, P.; Murphy, S.; Odom, J.; Oliversen, R.; Sheppard, D.

    2015-12-01

    The MAVEN magnetic field investigation is part of a comprehensive particles and fields subsystem that will measure the magnetic and electric fields and plasma environment of Mars and its interaction with the solar wind. The magnetic field instrumentation consists of two independent tri-axial fluxgate magnetometer sensors, remotely mounted at the outer extremity of the two solar arrays on small extensions ("boomlets"). The sensors are controlled by independent and functionally identical electronics assemblies that are integrated within the particles and fields subsystem and draw their power from redundant power supplies within that system. Each magnetometer measures the ambient vector magnetic field over a wide dynamic range (to 65,536 nT per axis) with a resolution of 0.008 nT in the most sensitive dynamic range and an accuracy of better than 0.05 %. Both magnetometers sample the ambient magnetic field at an intrinsic sample rate of 32 vector samples per second. Telemetry is transferred from each magnetometer to the particles and fields package once per second and subsequently passed to the spacecraft after some reformatting. The magnetic field data volume may be reduced by averaging and decimation, when necessary to meet telemetry allocations, and application of data compression, utilizing a lossless 8-bit differencing scheme. The MAVEN magnetic field experiment may be reconfigured in flight to meet unanticipated needs and is fully hardware redundant. A spacecraft magnetic control program was implemented to provide a magnetically clean environment for the magnetic sensors and the MAVEN mission plan provides for occasional spacecraft maneuvers—multiple rotations about the spacecraft x and z axes—to characterize spacecraft fields and/or instrument offsets in flight.

  5. The MAVEN Magnetic Field Investigation

    NASA Technical Reports Server (NTRS)

    Connerney, J. E. P.; Espley, J.; Lawton, P.; Murphy, S.; Odom, J.; Oliversen, R.; Sheppard, D.

    2014-01-01

    The MAVEN magnetic field investigation is part of a comprehensive particles and fields subsystem that will measure the magnetic and electric fields and plasma environment of Mars and its interaction with the solar wind. The magnetic field instrumentation consists of two independent tri-axial fluxgate magnetometer sensors, remotely mounted at the outer extremity of the two solar arrays on small extensions ("boomlets"). The sensors are controlled by independent and functionally identical electronics assemblies that are integrated within the particles and fields subsystem and draw their power from redundant power supplies within that system. Each magnetometer measures the ambient vector magnetic field over a wide dynamic range (to 65,536 nT per axis) with a quantization uncertainty of 0.008 nT in the most sensitive dynamic range and an accuracy of better than 0.05%. Both magnetometers sample the ambient magnetic field at an intrinsic sample rate of 32 vector samples per second. Telemetry is transferred from each magnetometer to the particles and fields package once per second and subsequently passed to the spacecraft after some reformatting. The magnetic field data volume may be reduced by averaging and decimation, when necessary to meet telemetry allocations, and application of data compression, utilizing a lossless 8-bit differencing scheme. The MAVEN magnetic field experiment may be reconfigured in flight to meet unanticipated needs and is fully hardware redundant. A spacecraft magnetic control program was implemented to provide a magnetically clean environment for the magnetic sensors and the MAVEN mission plan provides for occasional spacecraft maneuvers - multiple rotations about the spacecraft x and z axes - to characterize spacecraft fields and/or instrument offsets in flight.

  6. The Juno Magnetic Field Investigation

    NASA Astrophysics Data System (ADS)

    Connerney, J. E. P.; Benn, M.; Bjarno, J. B.; Denver, T.; Espley, J.; Jorgensen, J. L.; Jorgensen, P. S.; Lawton, P.; Malinnikova, A.; Merayo, J. M.; Murphy, S.; Odom, J.; Oliversen, R.; Schnurr, R.; Sheppard, D.; Smith, E. J.

    2017-02-01

    The Juno Magnetic Field investigation (MAG) characterizes Jupiter's planetary magnetic field and magnetosphere, providing the first globally distributed and proximate measurements of the magnetic field of Jupiter. The magnetic field instrumentation consists of two independent magnetometer sensor suites, each consisting of a tri-axial Fluxgate Magnetometer (FGM) sensor and a pair of co-located imaging sensors mounted on an ultra-stable optical bench. The imaging system sensors are part of a subsystem that provides accurate attitude information (to ˜20 arcsec on a spinning spacecraft) near the point of measurement of the magnetic field. The two sensor suites are accommodated at 10 and 12 m from the body of the spacecraft on a 4 m long magnetometer boom affixed to the outer end of one of 's three solar array assemblies. The magnetometer sensors are controlled by independent and functionally identical electronics boards within the magnetometer electronics package mounted inside Juno's massive radiation shielded vault. The imaging sensors are controlled by a fully hardware redundant electronics package also mounted within the radiation vault. Each magnetometer sensor measures the vector magnetic field with 100 ppm absolute vector accuracy over a wide dynamic range (to 16 Gauss = 1.6 × 106 nT per axis) with a resolution of ˜0.05 nT in the most sensitive dynamic range (±1600 nT per axis). Both magnetometers sample the magnetic field simultaneously at an intrinsic sample rate of 64 vector samples per second. The magnetic field instrumentation may be reconfigured in flight to meet unanticipated needs and is fully hardware redundant. The attitude determination system compares images with an on-board star catalog to provide attitude solutions (quaternions) at a rate of up to 4 solutions per second, and may be configured to acquire images of selected targets for science and engineering analysis. The system tracks and catalogs objects that pass through the imager field of

  7. Field investigation of keyblock stability

    SciTech Connect

    Yow, J.L. Jr.

    1985-04-01

    Discontinuities in a rock mass can intersect an excavation surface to form discrete blocks (keyblocks) which can be unstable. This engineering problem is divided into two parts: block identification, and evaluation of block stability. One stable keyblock and thirteen fallen keyblocks were observed in field investigations at the Nevada Test Site. Nine blocks were measured in detail sufficient to allow back-analysis of their stability. Measurements included block geometry, and discontinuity roughness and compressive strength. Back-analysis correctly predicted stability or failure in all but two cases. These two exceptions involved situations that violated the stress assumptions of the stability calculations. Keyblock faces correlated well with known joint set orientations. The effect of tunnel orientation on keyblock frequency was apparent. Back-analysis of physical models successfully predicted block pullout force for two-dimensional models of unit thickness. Two-dimensional (2D) and three-dimensional (3D) analytic models for the stability of simple pyramidal keyblocks were examined. Calculated stability is greater for 3D analyses than for 2D analyses. Calculated keyblock stability increases with larger in situ stress magnitudes, larger lateral stress ratios, and larger shear strengths. Discontinuity stiffness controls block displacement more strongly than it does stability itself. Large keyblocks are less stable than small ones, and stability increases as blocks become more slender. Rock mass temperature decreases reduce the confining stress magnitudes and can lead to failure. The pattern of stresses affecting each block face explains conceptually the occurrence of pyramidal keyblocks that are truncated near their apex.

  8. A 2-Year Field Study Shows Little Evidence That the Long-Term Planting of Transgenic Insect-Resistant Cotton Affects the Community Structure of Soil Nematodes

    PubMed Central

    Li, Xiaogang; Liu, Biao

    2013-01-01

    Transgenic insect-resistant cotton has been released into the environment for more than a decade in China to effectively control the cotton bollworm (Helicoverpa armigera) and other Lepidoptera. Because of concerns about undesirable ecological side-effects of transgenic crops, it is important to monitor the potential environmental impact of transgenic insect-resistant cotton after commercial release. Our 2-year study included 1 cotton field where non-transgenic cotton had been planted continuously and 2 other cotton fields where transgenic insect-resistant cotton had been planted for different lengths of time since 1997 and since 2002. In 2 consecutive years (2009 and 2010), we took soil samples from 3 cotton fields at 4 different growth stages (seedling, budding, boll-forming and boll-opening stages), collected soil nematodes from soil with the sugar flotation and centrifugation method and identified the soil nematodes to the genus level. The generic composition, individual densities and diversity indices of the soil nematodes did not differ significantly between the 2 transgenic cotton fields and the non-transgenic cotton field, but significant seasonal variation was found in the individual densities of the principal trophic groups and in the diversity indices of the nematodes in all 3 cotton fields. The study used a comparative perspective to monitor the impact of transgenic insect-resistant cotton grown in typical ‘real world’ conditions. The results of the study suggested that more than 10 years of cultivation of transgenic insect-resistant cotton had no significant effects–adverse or otherwise–on soil nematodes. This study provides a theoretical basis for ongoing environmental impact monitoring of transgenic plants. PMID:23613899

  9. Towards a validation of a cellular biomarker suite in native and transplanted zebra mussels: a 2-year integrative field study of seasonal and pollution-induced variations.

    PubMed

    Guerlet, Edwige; Ledy, Karine; Meyer, Antoinette; Giambérini, Laure

    2007-03-30

    Two of the questions raised in the validation process of biomarkers are their relevance in the identification and discrimination of environmental perturbations, and the influence of seasonal factors on these biological endpoints. Determining the advantages and restrictions associated with the use of native or transplanted animals and comparing their responses is also needed. To obtain this information, a 2-year integrative field study was conducted in the vicinity of a nuclear power plant in northeastern France. A station was located in the reservoir receiving the cooling waters of the plant, and two other sites were studied 2 km upstream and 5 km downstream from the reservoir's discharge in the Moselle river. Elevated temperatures, copper contamination and a 1.4-fold-concentration factor of dissolved salts affected water quality of the reservoir. Native and transplanted zebra mussels (Dreissena polymorpha) were collected monthly and their digestive glands were processed for histochemical determinations of the lysosomal and peroxisomal systems and of the lipofuscin and neutral lipid contents. The responses were quantified using automated image analysis and stereology. Apart from neutral lipid contents, there were no systematic seasonal patterns in mussel populations or from 1 year to another. Principal Component Analyses showed a general higher discrimination potential of biological responses in transplanted organisms compared to native ones. They also pointed out the relationships between the cellular and physiological markers and abiotic factors. The present multiple biomarker integrative approach in transplanted D. polymorpha brings promising elements in their validation process as relevant biomonitoring tools.

  10. Investigation Of Far-Field Diffraction

    NASA Technical Reports Server (NTRS)

    Wang, Yaujen; Scholl, Marija S.

    1993-01-01

    Report describes experimental investigation of far-field diffracton by normally illuminated circular apertures with diameters of several wavelengths of incident light. Purpose of investigation to determine whether Keller's "geometrical" theory of diffraction valid for diffraction phenomena of this kind.

  11. Developmental milestones record - 2 years

    MedlinePlus

    Growth milestones for children - 2 years; Normal childhood growth milestones - 2 years; Childhood growth milestones - 2 years ... a cause for concern if not seen by 2 years.) Can run with better coordination . (May still ...

  12. Field and laboratory investigations of selenium transformation

    SciTech Connect

    Atalay, A.; Koll, K.J.

    1990-12-01

    This quarterly report discusses the preparation and results of a field investigation of a selected coal mine site in Oklahoma. The field investigation has been on-going since July 1990. An analysis of this data would be useful in providing information for potential Se mobility from a coal mine site and the distribution of Se in a soil profile of reclaimed land. Also, included is the investigation and preliminary results of SeO{sub 3}{sup 2{minus}} adsorption and desorption using different soil media, including coal mine spoils (overburden).

  13. The magnetic field investigation on Cluster

    NASA Technical Reports Server (NTRS)

    Balogh, A.; Cowley, S. W. H.; Southwood, D. J.; Musmann, G.; Luhr, H.; Neubauer, F. M.; Glassmeier, K.-H.; Riedler, W.; Heyn, M. F.; Acuna, M. H.

    1988-01-01

    The magnetic field investigation of the Cluster four-spacecraft mission is designed to provide intercalibrated measurements of the B magnetic field vector. The instrumentation and data processing of the mission are discussed. The instrumentation is identical on the four spacecraft. It consists of two triaxial fluxgate sensors and of a failure tolerant data processing unit. The combined analysis of the four spacecraft data will yield such parameters as the current density vector, wave vectors, and the geometry and structure of discontinuities.

  14. Inlet flow field investigation. Part 1: Transonic flow field survey

    NASA Technical Reports Server (NTRS)

    Yetter, J. A.; Salemann, V.; Sussman, M. B.

    1984-01-01

    A wind tunnel investigation was conducted to determine the local inlet flow field characteristics of an advanced tactical supersonic cruise airplane. A data base for the development and validation of analytical codes directed at the analysis of inlet flow fields for advanced supersonic airplanes was established. Testing was conducted at the NASA-Langley 16-foot Transonic Tunnel at freestream Mach numbers of 0.6 to 1.20 and angles of attack from 0.0 to 10.0 degrees. Inlet flow field surveys were made at locations representative of wing (upper and lower surface) and forebody mounted inlet concepts. Results are presented in the form of local inlet flow field angle of attack, sideflow angle, and Mach number contours. Wing surface pressure distributions supplement the flow field data.

  15. Synthetic turf field investigation in Connecticut.

    PubMed

    Simcox, Nancy J; Bracker, Anne; Ginsberg, Gary; Toal, Brian; Golembiewski, Brian; Kurland, Tara; Hedman, Curtis

    2011-01-01

    The primary purpose of this study was to characterize the concentrations of volatile organic compounds (VOC), semivolatile organic compounds (SVOC), rubber-related chemicals such as benzothiazole (BZT) and nitrosamine, and particulate matter (PM(10)) in air at synthetic turf crumb rubber fields. Both new and older fields were evaluated under conditions of active use. Three types of fields were targeted: four outdoor crumb rubber fields, one indoor facility with crumb rubber turf, and an outdoor natural grass field. Background samples were collected at each field on grass. Personal air sampling was conducted for VOC, BZT, nitrosamines, and other chemicals. Stationary air samples were collected at different heights to assess the vertical profile of release. Air monitoring for PM(10) was conducted at one height. Bulk samples of turf grass and crumb rubber were analyzed, and meteorological data were recorded. Results showed that personal concentrations were higher than stationary concentrations and were higher on turf than in background samples for certain VOC. In some cases, personal VOC concentrations from natural grass fields were as high as those on turf. Naphthalene, BZT, and butylated hydroxytoluene (BHT) were detected in greater concentration at the indoor field compared to the outdoor fields. Nitrosamine air levels were below reporting levels. PM(10) air concentrations were not different between on-field and upwind locations. All bulk lead (Pb) samples were below the public health target of 400 ppm. More research is needed to better understand air quality at indoor facilities. These field investigation data were incorporated into a separate human health risk assessment.

  16. FIELD INVESTIGATIONS OF THE DRIFT SHADOW

    SciTech Connect

    G. W. Su, T. J. Kneafsey, T. A. Ghezzehei, B. D. Marshall, and P. J. Cook

    2006-01-15

    The ''Drift Shadow'' is defined as the relatively drier region that forms below subsurface cavities or drifts in unsaturated rock. Its existence has been predicted through analytical and numerical models of unsaturated flow. However, these theoretical predictions have not been demonstrated empirically to date. In this project they plan to test the drift shadow concept through field investigations and compare our observations to simulations. Based on modeling studies they have an identified suitable site to perform the study at an inactive mine in a sandstone formation. Pretest modeling studies and preliminary characterization of the site are being used to develop the field scale tests.

  17. Polypyrrole nanostructures and their field emission investigations

    NASA Astrophysics Data System (ADS)

    Harpale, Kashmira; More, Mahendra A.; Koinkar, Pankaj M.; Patil, Sandip S.; Sonawane, Kishor M.

    2015-03-01

    Polypyrrole (PPy) nanostructures have been synthesized on indium doped tin oxide (ITO) substrates by a facile electrochemical route employing cyclic voltammetry (CV) mode. The morphology of the PPy thin films was observed to be influenced by the monomer concentration. Furthermore, FTIR revealed formation of electrically conducting state of PPy. Field emission investigations of the PPy nanostructures were carried out at base pressure of 1×10-8mbar. The values of turn-on field, corresponding to emission current density of 1 μA/cm2 were observed to be 0.6, 1.0 and 1.2 V/μm for the PPy films characterized with rod-like, cauliflower and granular morphology, respectively. In case of PPy nanorods maximum current density of 1.2 mA/cm2 has been drawn at electric field of 1 V/μm. The low turn on field, extraction of very high emission current density at relatively lower applied field and good emission stability propose the PPy nanorods as a promising material for field emission based devices.

  18. Vertical profiles of aerosol and black carbon in the Arctic: a seasonal phenomenology along 2 years (2011-2012) of field campaigns

    NASA Astrophysics Data System (ADS)

    Ferrero, Luca; Cappelletti, David; Busetto, Maurizio; Mazzola, Mauro; Lupi, Angelo; Lanconelli, Christian; Becagli, Silvia; Traversi, Rita; Caiazzo, Laura; Giardi, Fabio; Moroni, Beatrice; Crocchianti, Stefano; Fierz, Martin; Močnik, Griša; Sangiorgi, Giorgia; Perrone, Maria G.; Maturilli, Marion; Vitale, Vito; Udisti, Roberto; Bolzacchini, Ezio

    2016-10-01

    We present results from a systematic study of vertical profiles of aerosol number size distribution and black carbon (BC) concentrations conducted in the Arctic, over Ny-Ålesund (Svalbard). The campaign lasted 2 years (2011-2012) and resulted in 200 vertical profiles measured by means of a tethered balloon (up to 1200 m a.g.l.) during the spring and summer seasons. In addition, chemical analysis of filter samples, aerosol size distribution and a full set of meteorological parameters were determined at ground. The collected experimental data allowed a classification of the vertical profiles into different typologies, which allowed us to describe the seasonal phenomenology of vertical aerosol properties in the Arctic. During spring, four main types of profiles were found and their behavior was related to the main aerosol and atmospheric dynamics occurring at the measuring site. Background conditions generated homogenous profiles. Transport events caused an increase of aerosol concentration with altitude. High Arctic haze pollution trapped below thermal inversions promoted a decrease of aerosol concentration with altitude. Finally, ground-based plumes of locally formed secondary aerosol determined profiles with decreasing aerosol concentration located at different altitude as a function of size. During the summer season, the impact from shipping caused aerosol and BC pollution plumes to be constrained close to the ground, indicating that increasing shipping emissions in the Arctic could bring anthropogenic aerosol and BC in the Arctic summer, affecting the climate.

  19. Planar dipolar polymer brush: field theoretical investigations

    NASA Astrophysics Data System (ADS)

    Mahalik, Jyoti; Kumar, Rajeev; Sumpter, Bobby

    2015-03-01

    Physical properties of polymer brushes bearing monomers with permanent dipole moments and immersed in a polar solvent are investigated using self-consistent field theory (SCFT). It is found that mismatch between the permanent dipole moments of the monomer and the solvent plays a significant role in determining the height of the polymer brush. Sign as well as magnitude of the mismatch determines the extent of collapse of the polymer brush. The mismatch in the dipole moments also affects the force-distance relations and interpenetration of polymers in opposing planar brushes. In particular, an attractive force between the opposing dipolar brushes is predicted for stronger mismatch parameter. Furthermore, effects of added monovalent salt on the structure of dipolar brushes will also be presented. This investigation highlights the significance of dipolar interactions in affecting the physical properties of polymer brushes. Csmd division, Oak Ridge National Laboratory, 1 Bethel Valley Rd, Oak Ridge, TN 37831, USA.

  20. Progress with field investigations at Stripa

    SciTech Connect

    Witherspoon, P.A.; Cook, N.G.W.; Gale, J.E.

    1980-02-01

    It is generally agreed that the most practicable method of isolating nuclear wastes from the biosphere is by deep burial in suitable geologic formations. Such burial achieves a high degree of physical isolation but raises questions concerning the rate at which some of these wastes may return to the biosphere through transport by groundwater. Any suitable repository site will be disturbed first by the excavation of the repository and second by the thermal pulse caused by the radioactive decay of the wastes. To assess the effectiveness of geologic isolation it is necessary to develop the capability of predicting the response of a rock mass to such a thermal pulse. Ultimately, this requires field measurements at depths below surface and in media representative of those likely to be encountered at an actual repository. Access to a granitic rock mass adjacent to a defunct iron ore mine at Stripa in Sweden at a depth of about 350 m below surface has provided a unique opportunity to conduct a comprehensive suite of hydrological and thermo-mechanical experiments under such conditions virtually without delay. The results of these field tests have shown the importance of geologic structure and the functional dependence of the thermo-mechanical properties on temperature in developing a valid predictive model. The results have also demonstrated the vital importance of being able to carry out large scale investigations in a field test facility.

  1. Hurricane Ike: Field Investigation Survey (Invited)

    NASA Astrophysics Data System (ADS)

    Ewing, L.

    2009-12-01

    Hurricane Ike made landfall at 2:10 a.m. on September 13, 2008, as a Category 2 hurricane. The eye of the hurricane crossed over the eastern end of Galveston Island and a large region of the Texas and Louisiana coast experienced extreme winds, waves and water levels, resulting in large impacts from overtopping, overwash, wind and wave forces and flooding. Major damage stretched from Freeport to the southwest and to Port Arthur to the northeast. The effects of the hurricane force winds were felt well inland in Texas and Louisiana and the storm continued to the interior of the US, causing more damage and loss of life. Through the support of the Coasts, Oceans, Ports and Rivers Institute (COPRI) of the American Society of Civil Engineers (ASCE) a team of 14 coastal scientists and engineers inspected the upper Texas coast in early October 2008. The COPRI team surveyed Hurricane Ike’s effects on coastal landforms, structures, marinas, shore protection systems, and other infrastructure. Damages ranges from very minor to complete destruction, depending upon location and elevation. Bolivar Peninsula, to the right of the hurricane path, experienced severe damage and three peninsula communities were completely destroyed. Significant flood and wave damage also was observed in Galveston Island and Brazoria County that were both on the left side of the hurricane path. Beach erosion and prominent overwash fans were observed throughout much of the field investigation area. The post-storm damage survey served to confirm expected performance under extreme conditions, as well as to evaluate recent development trends and conditions unique to each storm. Hurricane Ike confirmed many previously reported observations. One of the main conclusions from the inspection of buildings was that elevation was a key determinant for survival. Elevation is also a major factor in the stability and effectiveness of shore protection. The Galveston Seawall was high enough to provide protection from

  2. The Electron Losses and Fields Investigation

    NASA Astrophysics Data System (ADS)

    Bingley, L.; Angelopoulos, V.; Caron, R.; Zarifian, A.; Miller, J.; Gildemeister, A.; Schoen, B.; Tsai, E.; Berger, S.; Zhang, F.; Subramanian, A.; Chung, M.; Runov, A.; Cruce, P. R.

    2015-12-01

    The Electron Losses and Fields Investigation (ELFIN), is a joint NASA/NSF funded project at the University of California, Los Angeles focusing on eliminating the current deficit in the understanding of the innate physical processes behind geomagnetic storms. Set to launch in 2017, the mission takes advantage of a 3U+ CubeSat design to reduce cost and complexity traditionally associated with a space weather mission of this kind. This mission seeks to quantify the precipitation of relativistic electrons from the radiation belts using a pair of energetic particle detectors (EPDs). The spacecraft will also fly a fluxgate magnetometer (FGM) for determining the pitch angle distribution of the particles, which in conjunction with the EPDs will provide insight to the mechanisms responsible for their loss. Electromagnetic Ion Cyclotron (EMIC) waves are thought to be a significant contributor to the precipitation of electrons trapped in the magnetosphere; however without direct measurement to verify the exact energy range of the particles with high angular resolution, the precise role of these waves is as yet undetermined. ELFIN is unique as it is the first spacecraft that will perform direct pitch angle measurements of the high-energy electrons at the region in the ionosphere where the particles are being lost. Together with correlative measurements from THEMIS, Van Allen Probes and the upcoming ERG mission, ELFIN will provide a unique dataset of magnetospheric wave-particle interactions that will be able to contribute to a marked increase in the fidelity of current space weather models.

  3. Social Development:: 2 Year Olds

    MedlinePlus

    ... Español Text Size Email Print Share Social Development: 2 Year Olds Page Content Article Body By nature, ... probably are acting the same way. At age two, children view the world almost exclusively through their ...

  4. Field investigation of the drift shadow

    SciTech Connect

    Su, Grace W.; Kneafsey, Timothy J.; Ghezzehei, Teamrat A.; Marshall, Brian D.; Cook, Paul J.

    2005-09-08

    A drift shadow is an area immediately beneath an undergroundvoidthat, in theory, will be relatively drier than the surrounding rockmass. Numerical and analytical models of water flow through unsaturatedrock predict the existence of a drift shadow, but field tests confirmingits existence have yet to be performed. Proving the existence of driftshadows and understanding their hydrologic and transport characteristicscould provide a better understanding of how contaminants move in thesubsurface if released from waste emplacement drifts such as the proposednuclear waste repository at Yucca Mountain, Nevada. We describe the fieldprogram that will be used to investigate the existence of a drift shadowand the corresponding hydrological process at the Hazel-Atlas silica-sandmine located at the Black Diamond Mines Regional Preserve in Antioch,California. The location and configuration of this mine makes it anexcellent site to observe and measure drift shadow characteristics. Themine is located in a porous sandstone unit of the Domengine Formation, anapproximately 230 meter thick series of interbedded Eocene-age shales,coals, and massive-bedded sandstones. The mining method used at the minerequired the development of two parallel drifts, one above the other,driven along the strike of the mined sandstone stratum. Thisconfiguration provides the opportunity to introduce water into the rockmass in the upper drift and to observe and measure its flow around theunderlying drift. The passive and active hydrologic tests to be performedare described. In the passive method, cores will be obtained in a radialpattern around a drift and will be sectioned and analyzed for in-situwater content and chemical constituents. With the active hydrologic test,water will be introduced into the upper drift of the two parallel driftsand the flow of the water will be tracked as it passes near the bottomdrift. Tensiometers, electrical resistance probes, neutron probes, andground penetrating radar may be

  5. Manus Water Isotope Investigation Field Campaign Report

    SciTech Connect

    Conroy, Jessica L; Cobb, Kim M; Noone, David

    2016-03-01

    The objective of this field campaign was to investigate climatic controls on the stable isotopic composition of water vapor, precipitation, and seawater in the western tropical Pacific. Simultaneous measurements of the stable isotopic composition of vapor and precipitation from April 28 to May 8, 2013, at the Manus Tropical Western Pacific Atmospheric Radiation Measurement site, provided several key insights into the nature of the climate signal archived in precipitation and vapor isotope ratios. We observed a large shift from lower to higher isotopic values in vapor and precipitation because of the passage of a mesoscale convective system west of the site and a transition from a regional stormy period into a more quiescent period. During the quiescent period, the stable isotopic composition of vapor and precipitation indicated the predominance of oceanic evaporation in determining the isotopic composition of boundary-layer vapor and local precipitation. There was not a consistent relationship between intra-event precipitation amount at the site and the stable isotopic composition of precipitation, thus challenging simplified assumptions about the isotopic “amount effect” in the tropics on the time scale of individual storms. However, some storms did show an amount effect, and deuterium excess values in precipitation had a significant relationship with several meteorological variables, including precipitation, temperature, relative humidity, and cloud base height across all measured storms. The direction of these relationships points to condensation controls on precipitation deuterium excess values on intra-event time scales. The relationship between simultaneous measurements of vapor and precipitation isotope ratios during precipitation events indicates the ratio of precipitation-to-vapor isotope ratios can diagnose precipitation originating from a vapor source unique from boundary-layer vapor and rain re-evaporation.

  6. Emotional Development: 2 Year Olds

    MedlinePlus

    ... Español Text Size Email Print Share Emotional Development: 2 Year Olds Page Content Article Body It’s so ... to follow the ups and downs of a two-year-old. One moment he’s beaming and friendly; ...

  7. Magnetic Field Investigations During ROSETTA's Steins Flyby

    NASA Astrophysics Data System (ADS)

    Glassmeier, K.; Auster, H.; Richter, I.; Motschmann, U.; RPC/ROMAP Teams

    2009-05-01

    During the recent Steins flyby of the ROSETTA spacecraft magnetic field measurements have been made with both, the RPC orbiter magnetometer and the ROMAP lander magnetometer. These combined magnetic field measurements allow a detailed examination of any magnetic signatures caused either directly by the asteroid or indirectly by Steins different modes of interaction with the solar wind. Comparing our measurements with simulation results show that Steins does not possess a significant remanent magnetization. The magnetization is estimated at less than 1 mAm2/kg. This is significantly different from results at Braille and Gaspra.

  8. Stream temperature investigations: field and analytic methods

    USGS Publications Warehouse

    Bartholow, J.M.

    1989-01-01

    Alternative public domain stream and reservoir temperature models are contrasted with SNTEMP. A distinction is made between steady-flow and dynamic-flow models and their respective capabilities. Regression models are offered as an alternative approach for some situations, with appropriate mathematical formulas suggested. Appendices provide information on State and Federal agencies that are good data sources, vendors for field instrumentation, and small computer programs useful in data reduction.

  9. Some results of Moon's gravitational field investigations

    NASA Astrophysics Data System (ADS)

    Haigel, Y. I.; Zazulyak, P. M.

    2016-10-01

    The task of studying the gravitational field of the moon is important for long-term planning of its research using manned and robotic spacecrafts. Determination of harmonic expansion coefficients of selenopotential may not be reliable because of their construction based on different data and different methods of mathematical processing. With mutual comparative assessment of selenopotential models we can get some information about the reliability determination harmonic coefficients.

  10. Investigating High Field Gravity using Astrophysical Techniques

    SciTech Connect

    Bloom, Elliott D.; /SLAC

    2008-02-01

    The purpose of these lectures is to introduce particle physicists to astrophysical techniques. These techniques can help us understand certain phenomena important to particle physics that are currently impossible to address using standard particle physics experimental techniques. As the subject matter is vast, compromises are necessary in order to convey the central ideas to the reader. Many general references are included for those who want to learn more. The paragraphs below elaborate on the structure of these lectures. I hope this discussion will clarify my motivation and make the lectures easier to follow. The lectures begin with a brief review of more theoretical ideas. First, elements of general relativity are reviewed, concentrating on those aspects that are needed to understand compact stellar objects (white dwarf stars, neutron stars, and black holes). I then review the equations of state of these objects, concentrating on the simplest standard models from astrophysics. After these mathematical preliminaries, Sec. 2(c) discusses 'The End State of Stars'. Most of this section also uses the simplest standard models. However, as these lectures are for particle physicists, I also discuss some of the more recent approaches to the equation of state of very dense compact objects. These particle-physics-motivated equations of state can dramatically change how we view the formation of black holes. Section 3 focuses on the properties of the objects that we want to characterize and measure. X-ray binary systems and Active Galactic Nuclei (AGN) are stressed because the lectures center on understanding very dense stellar objects, black hole candidates (BHCs), and their accompanying high gravitational fields. The use of x-ray timing and gamma-ray experiments is also introduced in this section. Sections 4 and 5 review information from x-ray and gamma-ray experiments. These sections also discuss the current state of the art in x-ray and gamma-ray satellite experiments and

  11. [Field investigations of the air pollution level of populated territories].

    PubMed

    Vinokurov, M V

    2014-01-01

    The assessment and management of air quality of settlements is one of the priorities in the field of environmental protection. In the management of air quality the backbone factor is the methodology of the organization, performance and interpretation of data of field investigations. The present article is devoted to the analysis of the existing methodological approaches and practical aspects of their application in the organization and performance of field investigations with the aim to confirm the adequacy of the boundaries of the sanitary protection zone in the old industrial regions, hygienic evaluation of the data of field investigations of the air pollution level.

  12. Assessment and 2-Year Institutions.

    ERIC Educational Resources Information Center

    Bradley, Jama L.; And Others

    1994-01-01

    Describes a national study of the current availability and use of commercially and institutionally developed educational assessment instruments. Indicates that two-year institutions reported less activity than four-year institutions in assessing the major fields of study but that 77% of all two-year institutions assessed basic skills. (MAB)

  13. Electric field response in bilayer graphene: Ab initio investigation

    NASA Astrophysics Data System (ADS)

    Mori, Yutaro; Minamitani, Emi; Ando, Yasunobu; Kasamatsu, Shusuke; Watanabe, Satoshi

    2016-11-01

    Stimulated by quantum capacitance measurements, we have investigated the electric properties of bilayer graphene (BLG) with carrier doping under an external electric field using ab initio calculations. We found that the relative permittivity of BLG depends weakly on the applied electric field, and that the BLG can be regarded as a dielectric material rather than a pair of metallic films. We also found that carrier doping affects the band gap of BLG under electric fields, although carrier doping has a much smaller effect on the band gap and density of states than the application of electric fields.

  14. Field and laboratory investigations of selenium transformation. Quarterly report

    SciTech Connect

    Atalay, A.; Koll, K.J.

    1990-12-01

    This quarterly report discusses the preparation and results of a field investigation of a selected coal mine site in Oklahoma. The field investigation has been on-going since July 1990. An analysis of this data would be useful in providing information for potential Se mobility from a coal mine site and the distribution of Se in a soil profile of reclaimed land. Also, included is the investigation and preliminary results of SeO{sub 3}{sup 2{minus}} adsorption and desorption using different soil media, including coal mine spoils (overburden).

  15. Investigations of Magnetically Enhanced RIE Reactors with Rotating Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Babaeva, Natalia Yu.; Kushner, Mark J.

    2008-10-01

    In Magnetically Enhanced Reactive Ion Etching (MERIE) reactors, a magnetic field parallel to the substrate enables higher plasma densities and control of ion energy distributions. Since it is difficult to make the B-field uniform across the wafer, the B-field is often azimuthally rotated at a few Hz to average out non-uniformities. The rotation is slow enough that the plasma is in quasi-equilibrium with the instantaneous B-field. For the pressures (10's mTorr or less) and B-fields (10's - 100's G) of interest, electrons are magnetized whereas ions are usually not. The orientation and intersection of the B-field with the wafer are important, as intersecting field lines provide a low resistance path for electron current to the substrate. We report on a modeling study of plasma properties in MERIE reactors having rotating B-fields by investigating a series of quasi-steady states of B-field profiles. To resolve side-to-side variations, computations are performed in Cartesian coordinates. The model, nonPDPSIM, was improved with full tensor conductivities in the fluid portions of the code and v x B forces in the kinetic portions. Results are discussed while varying the orientation and strength of the B-field for electropositive (argon) and electronegative (Ar/CxFy, Ar/Cl2) gas mixtures.

  16. Shemya AFB, Alaska 1992 IRP field investigation report

    SciTech Connect

    Not Available

    1993-02-01

    The US Air Force is currently investigating 22 sites on Shemya Air Force Base (AFB) to determine if past spill and disposal activities have caused environmental damage. These investigations are being carried out under the Air Force's Installation Restoration Program (IRP). As a part of the IRP program, field investigations were performed in 1992 to obtain the information needed to assess what future actions willneed to be carried out at each site. The island's drinking water supply was also investigated. Activities completed at 10 selected sites during the 1992 field investigation included surface sampling to determine the lateral extent of contamination, subsurface sampling to determine the vertical extent of contamination, and the installation of well points and monitoring wells to determine the direction of groundwater flow and if the groundwater has been affected by a site. In addition, geophysical surveys were performed at most sites to identify site boundaries and check for the presence of buried metal to be avoided during drilling activities.

  17. Your Child's Development: 2 Years (24 Months)

    MedlinePlus

    ... 1- to 2-Year-Old Your Child’s Development: 2 Years (24 Months) KidsHealth > For Parents > Your Child’s Development: 2 Years (24 Months) Print A A A en español El desarrollo de su hijo: 2 años (24 meses) Tired of changing diapers? When ...

  18. Investigation of co-genotoxic effects of radiofrequency electromagnetic fields in vivo.

    PubMed

    Verschaeve, L; Heikkinen, P; Verheyen, G; Van Gorp, U; Boonen, F; Vander Plaetse, F; Maes, A; Kumlin, T; Mäki-Paakkanen, J; Puranen, L; Juutilainen, J

    2006-05-01

    We investigated the possible combined genotoxic effects of radiofrequency (RF) electromagnetic fields (900 MHz, amplitude modulated at 217 Hz, mobile phone signal) with the drinking water mutagen and carcinogen 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX). Female rats were exposed to RF fields for a period of 2 years for 2 h per day, 5 days per week at average whole-body specific absorption rates of 0.3 or 0.9 W/kg. MX was given in the drinking water at a concentration of 19 microg/ml. Blood samples were taken at 3, 6 and 24 months of exposure and brain and liver samples were taken at the end of the study (24 months). DNA damage was assessed in all samples using the alkaline comet assay, and micronuclei were determined in erythrocytes. We did not find significant genotoxic activity of MX in blood and liver cells. However, MX induced DNA damage in rat brain. Co-exposures to MX and RF radiation did not significantly increase the response of blood, liver and brain cells compared to MX exposure only. In conclusion, this 2-year animal study involving long-term exposures to RF radiation and MX did not provide any evidence for enhanced genotoxicity in rats exposed to RF radiation.

  19. Investigation on Amari's dynamical neural field with global constant inhibition.

    PubMed

    Jin, Dequan; Peng, Jigen

    2015-11-01

    In this paper, the properties of Amari's dynamical neural field with global constant inhibition induced by its kernel are investigated. Amari's dynamical neural field illustrates many neurophysiological phenomena successfully and has been applied to unsupervised learning like data clustering in recent years. In its applications, the stationary solution to Amari's dynamical neural field plays an important role that the underlying patterns being perceived are usually presented as the excited region in it. However, the type of stationary solution to dynamical neural field with typical kernel is often sensitive to parameters of its kernel that limits its range of application. Different from dynamical neural field with typical kernel that have been discussed a lot, there are few theoretical results on dynamical neural field with global constant inhibitory kernel that has already shown better performance in practice. In this paper, some important results on existence and stability of stationary solution to dynamical neural field with global constant inhibitory kernel are obtained. All of these results show that such kind of dynamical neural field has better potential for missions like data clustering than those with typical kernels, which provide a theoretical basis of its further extensive application.

  20. Barchan dune corridors: Field characterization and investigation of control parameters

    NASA Astrophysics Data System (ADS)

    Elbelrhiti, H.; Andreotti, B.; Claudin, P.

    2008-06-01

    The structure of the barchan field located between Tarfaya and Laayoune (Atlantic Sahara, Morocco) is quantitatively investigated and compared to that in La Pampa de la Joya (Arequipa, Peru). On the basis of field measurements, we show how the volume, the velocity, and the output sand flux of a dune can be computed from the value of its body and horn widths. The dune size distribution is obtained from the analysis of aerial photographs. It shows that these fields are in a statistically homogeneous state along the wind direction and present a "corridor" structure in the transverse direction, in which the dunes have a rather well selected size. Investigating the possible external parameters controlling these corridors, we demonstrate that none among topography, granulometry, wind, and sand flux is relevant. We finally discuss the dynamical processes at work in these fields (collisions and wind fluctuations) and investigate the way they could regulate the size of the dunes. Furthermore, we show that the overall sand flux transported by a dune field is smaller than the maximum transport that could be reached in the absence of dunes, i.e., in saltation over the solid ground.

  1. Analytical and numerical investigations of bubble behavior in electric fields

    NASA Astrophysics Data System (ADS)

    Vorreiter, Janelle Orae

    The behavior of gas bubbles in liquids is important in a wide range of applications. This study is motivated by a desire to understand the motion of bubbles in the absence of gravity, as in many aerospace applications. Phase-change devices, cryogenic tanks and life-support systems are some of the applications where bubbles exist in space environments. One of the main difficulties in employing devices with bubbles in zero gravity environments is the absence of a buoyancy force. The use of an electric field is found to be an effective means of replacing the buoyancy force, improving the control of bubbles in space environments. In this study, analytical and numerical investigations of bubble behavior under the influence of electric fields are performed. The problem is a difficult one in that the physics of the liquid and the electric field need to be considered simultaneously to model the dynamics of the bubble. Simplifications are required to reduce the problem to a tractable form. In this work, for the liquid and the electric field, assumptions are made which reduce the problem to one requiring only the solution of potentials in the domain of interest. Analytical models are developed using a perturbation analysis applicable for small deviations from a spherical shape. Numerical investigations are performed using a boundary integral code. A number of configurations are found to be successful in promoting bubble motion by varying properties of the electric fields. In one configuration, the natural frequencies of a bubble are excited using time-varying electric and pressure fields. The applied electric field is spatially uniform with frequencies corresponding to shape modes of the bubble. The resulting bubble velocity is related to the strength of the electric field as well as the characteristics of the applied fields. In another configuration, static non-uniform fields are used to encourage bubble motion. The resulting motion is related to the degree of non

  2. Near-field investigations of nanoshell cylinder dimers

    NASA Astrophysics Data System (ADS)

    Höflich, Katja; Gösele, Ulrich; Christiansen, Silke

    2009-10-01

    Metallic nanoparticles are known to exhibit strong particle size dependent localized surface plasmon resonances due to their specific optical response described via the complex dielectric function. Using the two-dimensional finite element method, the near-field behavior of core-shell nanocylinder dimers with either a dielectric or a gold core and a silver shell was investigated. With a detailed analysis the positions of maximum field enhancement usable for highly sensitive spectroscopy were unveiled and the surface charge distributions of the different kinds of resonances were visualized. It is shown that the usual far-field spectra do not give reliable estimates of local electric field peaks. Furthermore one observes a distinct mode at the natural plasma frequency of the silver shell which is independent of the core material. This mode is identified as a volume plasmon mode.

  3. Geoengineering characterization of welded tuffs from laboratory and field investigations

    SciTech Connect

    Zimmerman, R.M.; Nimick, F.B.; Board, M.P.

    1984-12-31

    Welded tuff beneath Yucca Mountain adjacent to the Nevada Test Site (NTS) is being considered for development as a high-level radioactive waste repository by the Nevada Nuclear Waste Storage Investigations (NNWSI) Project. Because access into Yucca Mountain has been limited to borehole explorations, early geoengineering materials characterizations have been derived from laboratory tests on cores from Yucca Mountain and from laboratory and field tests on welded tuffs located in G-Tunnel on the NTS. G-Tunnel contains welded tuffs that have similar properties and stress states to those at Yucca Mountain and has been the location for in situ rock mechanics testing. The purpose of this paper is to summarize the geoengineering material property data obtained to date and to compare appropriate laboratory and field data from G-Tunnel to findings from Yucca Mountain. Geomechanical and thermal data are provided and are augmented by limited geological and hydrological data. A comparison of results of laboratory measurements on tuffs from Yucca Mountain and G-Tunnel indicates good agreement between the bulk densities, saturations, moduli of elasticity, Poisson`s ratios, and P-wave velocities. The G-Tunnel tuff has slightly lower thermal conductivity, tensile strength, compressive strength and slightly higher matrix permeability than does the welded tuff near the proposed repository horizon at Yucca Mountain. From a laboratory-to-field scaling perspective, the modulus of deformation shows the most sensitivity to field conditions because of the presence of the joints found in the field. 14 references, 1 table.

  4. Geoengineering characterization of welded tuffs from laboratory and field investigations

    SciTech Connect

    Zimmerman, R.M.; Nimick, F.B.; Board, M.P.

    1984-12-31

    Welded tuff beneath Yucca Mountain adjacent to the Nevada Test Site (NTS) is being considered for development as a high-level radioactive waste repository by the Nevada Nuclear Waste Storage Investigations (NNWSI) Project. Because access into Yucca Mountain has been limited to borehole explorations, early geoengineering materials characterizations have been derived from laboratory tests on cores from Yucca Mountain and from laboratory and field tests on welded tuffs located in G-Tunnel on the NTS. G-Tunnel contains welded tuffs that have similar properties and stress states to those at Yucca Mountain and has been the location for in situ rock mechanics testing. The purpose of this paper is to summarize the geoengineering material property data obtained to date and to compare appropriate laboratory and field data from G-Tunnel to findings from Yucca Mountain. Geomechanical and thermal data are provided and are augmented by limited geological and hydrological data. A comparison of results of laboratory measurements on tuffs from Yucca Mountain and G-Tunnel indicates good agreement between the bulk densities, saturations, moduli of elasticity, Poisson`s ratios, and P-wave velocities. The G-Tunnel tuff has slightly lower thermal conductivity, tensile strength, compressive strength and slightly higher matrix permeability than does the welded tuff near the proposed repository horizon at Yucca Mountain. From a laboratory-to-field scaling perspective, the modulus of deformation shows the most sensitivity to field conditions because of the presence of joints found in the field. 14 refs., 1 tab.

  5. Field investigation to assess nutrient emission from paddy field to surface water in river catchment

    NASA Astrophysics Data System (ADS)

    Kogure, Kanami; Aichi, Masaatsu; Zessner, Matthias

    2015-04-01

    In order to maintain good river environment, it is remarkably important to understand and to control nutrient behavior such as Nitrogen and Phosphorus. Our former research dealing with nutrient emission analysis in the Tone River basin area in Japan, in addition to urban and industrial waste water, nutrient emission from agricultural activity is dominant pollution source into the river system. Japanese style agriculture produces large amount of rice and paddy field occupies large areas in Japanese river basin areas. While paddy field can deteriorate river water quality by outflow of fertilizer, it is also suggested that paddy field has water purification function. As we carried out investigation in the Tone River Basin area, data were obtained which dissolved nitrogen concentration is lower in discharging water from paddy field than inflowing water into the field. Regarding to nutrient emission impact from paddy field, sufficient data are required to discuss quantitatively seasonal change of material behavior including flooding season and dry season, difference of climate condition, soil type, and rice species, to evaluate year round comprehensive impact from paddy field to the river system. In this research, field survey in paddy field and data collection relating rice production were carried out as a preliminary investigation to assess how Japanese style paddy field contributes year round on surface water quality. Study sites are three paddy fields located in upper reach of the Tone River basin area. The fields are flooded from June to September. In 2014, field investigations were carried out three times in flooding period and twice in dry period. To understand characteristics of each paddy field and seasonal tendency accompanying weather of agricultural event, short term investigations were conducted and we prepare for further long term investigation. Each study site has irrigation water inflow and outflow. Two sites have tile drainage system under the field and

  6. Investigation of flow fields within large scale hypersonic inlet models

    NASA Technical Reports Server (NTRS)

    Gnos, A. V.; Watson, E. C.; Seebaugh, W. R.; Sanator, R. J.; Decarlo, J. P.

    1973-01-01

    Analytical and experimental investigations were conducted to determine the internal flow characteristics in model passages representative of hypersonic inlets for use at Mach numbers to about 12. The passages were large enough to permit measurements to be made in both the core flow and boundary layers. The analytical techniques for designing the internal contours and predicting the internal flow-field development accounted for coupling between the boundary layers and inviscid flow fields by means of a displacement-thickness correction. Three large-scale inlet models, each having a different internal compression ratio, were designed to provide high internal performance with an approximately uniform static-pressure distribution at the throat station. The models were tested in the Ames 3.5-Foot Hypersonic Wind Tunnel at a nominal free-stream Mach number of 7.4 and a unit free-stream Reynolds number of 8.86 X one million per meter.

  7. Interpretation and communication of the results of medical field investigations.

    PubMed

    Schulte, P A; Singal, M

    1989-07-01

    Since the controversy over cytogenetic test results at the Love Canal in New York State, there has been increasing concern about the communication of medical test results to participants in field studies. To identify the range of issues that arise and to present examples of practices that might be useful for consideration, we have drawn from 15 years of experience in interpreting and communicating the results of medical field investigations by the National Institute for Occupational Safety and Health. The investigations were qualitatively characterized according to study type and design, substances involved, language used in the notification of results, and the nature of the efforts to put results in perspective. Based on this evaluation, the following recommendations are made: (1) provide a comprehensible consent form, (2) interpret results for study participants, (3) use clear language, (4) be explicit about uncertainty of findings, (5) where appropriate, indicate the need for medical follow-up, (6) provide results promptly, (7) provide overall study results, (8) evaluate the impact of the notification, (9) train investigators in the practice of communicating results.

  8. Investigation of the effective field in magnetic fluids

    SciTech Connect

    Smirnov, V.I.

    1986-07-01

    The authors describe investigations of the effective field caused by the orientational interaction between ferroparticles for magnetic fluids with a conducting and a nonconducting base. The magnetic susceptibility of four magnetic fluid specimens was investigated. Specimens consisted of a colloid solution of magnetite in kerosene, stabilized with oleic acid; mercury-based magnetic fluids, a colloid solution of finely dispersed iron particles in mercury, a solution of iron particles with a lower degree of dispersion, and a solution of cobalt particles. Figures show the temperature dependences of the magnetic suceptibility of the fluid specimens. It was shown that under certain conditions, it is possible that instabilities can arise and heterophase impurities can form in accordance with the mechanism proposed previously in both electrically conducting and nonconducting magnetic fluids.

  9. Investigation of drag effect using the field signature method

    NASA Astrophysics Data System (ADS)

    Wan, Zhengjun; Liao, Junbi; Tian, Gui Yun; Cheng, Liang

    2011-08-01

    The potential drop (PD) method is an established non-destructive evaluation (NDE) technique. The monitoring of internal corrosion, erosion and cracks in piping systems, based on electrical field mapping or direct current potential drop array, is also known as the field signature method (FSM). The FSM has been applied in the field of submarine pipe monitoring and land-based oil and gas transmission pipes and containers. In the experimental studies, to detect and calculate the degree of pipe corrosion, the FSM analyses the relationships between the electrical resistance and pipe thickness using an electrode matrix. The relevant drag effect or trans-resistance will cause a large margin of error in the application of resistance arrays. It is the first time that the drag effect in the paper is investigated and analysed in resistance networks with the help of the FSM. Subsequently, a method to calculate the drag factors and eliminate its errors is proposed and presented. Theoretical analysis, simulation and experimental results show that the measurement accuracy can be improved by eliminating the errors caused by the drag effect.

  10. Investigation of a supersonic cruise fighter model flow field

    NASA Technical Reports Server (NTRS)

    Reubush, D. E.; Bare, E. A.

    1985-01-01

    An investigation was conducted in the Langley 16-Foot Transonic Tunnel to survey the flow field around a model of a supersonic cruise fighter configuration. Local values of angle of attack, side flow, Mach number, and total pressure ratio were measured with a single multi-holed probe in three survey areas on a model previously used for nacelle/nozzle integration investigations. The investigation was conducted at Mach numbers of 0.6, 0.9, and 1.2, and at angles of attack from 0 deg to 10 deg. The purpose of the investigation was to provide a base of experimental data with which theoretically determined data can be compared. To that end the data are presented in tables as well as graphically, and a complete description of the model geometry is included as fuselage cross sections and wing span stations. Measured local angles of attack were generally greater than free stream angle of attack above the wing and generally smaller below. There were large spanwise local angle-of-attack and side flow gradients above the wing at the higher free stream angles of attack.

  11. Shemya AFB, Alaska 1992 IRP field investigation report

    SciTech Connect

    Not Available

    1993-02-01

    The US Air Force is currently investigating 22 sites on Shemya Air Force Base (AFB) to determine if past spill and disposal activities have caused environmental damage. These investigations are being carried out under the Air Force's Installation Restoration Program (IRP). Field investigations were performed in 1992 to obtain the information needed to assess what future actions will need to be carried out at each site. The island's drinking water supply was also investigated. Activities completed at 10 selected sites included surface sampling to determine the lateral extent of contamination, subsurface sampling to determine the vertical extent of contamination, and the installation of well points and monitoring wells to determine the direction of groundwater flow and if the groundwater has been affected by a site. Geophysical surveys were performed at most sites to identify site boundaries and check for the presence of buried metal to be avoided during drilling activities. This report, appendices B, C, and D contains information on the following: geophysical contour maps and profile plots; human health risk assessment; and ecological risk assessment.

  12. Shemya AFB, Alaska 1992 IRP field investigation report

    SciTech Connect

    Not Available

    1993-02-01

    The US Air Force is currently investigating 22 sites on Shemya Air Force Base (AFB) to determine if past spill and disposal activities have caused environmental damage. These investigations are being carried out under the Air Force's Installation Restoration Program (IRP). Field investigations were performed in 1992 to obtain the information needed to assess what future actions will need to be carried out at each site. The island's drinking water supply was also investigated. Activities completed at 10 selected sites included surface sampling to determine the lateral extent of contamination, subsurface sampling to determine the vertical extent of contamination, and the installation of well points and monitoring wells to determine the direction of groundwater flow and if the groundwater has been affected by a site. In addition, geophysical surveys were performed at most sites to identify site boundaries and check for the presence of buried metal, to be avoided during drilling activities. This report contains appendices E and F with information on the following: soil boring logs, and data validation of samples analyzed.

  13. Investigation of the Arcjet near Field Plume Using Electrostatic Probes

    NASA Technical Reports Server (NTRS)

    Sankovic, John M.

    1990-01-01

    The near field plume of a 1 kW class arcjet thruster was investigated using electrostatic probes of various geometries. The electron number densities and temperatures were determined in a simulated hydrazine plume at axial distances between 3 cm (1.2 in.) and 15 cm (5.9 in.) and radial distances extending to 10 cm (3.9 in.) off centerline. Values of electron number densities obtained using cylindrical and spherical probes of different geometries agreed very well. The electron density on centerline followed a source flow approximation for axial distances as near as 3 cm (1.2 in.) from the nozzle exit plane. The model agreed well with previously obtained data in the far field. The effects of propellant mass flow rate and input power level were also studied. Cylindrical probes were used to obtain ion streamlines by changing the probe orientation with respect to the flow. The effects of electrical configuration on the plasma characteristics of the plume were also investigated by using a segmented anode/nozzle thruster. The results showed that the electrical configuration in the nozzle affected the distribution of electrons in the plume.

  14. Investigation of the arcjet plume near field using electrostatic probes

    NASA Technical Reports Server (NTRS)

    Sankovic, John M.

    1990-01-01

    The near field plum of a 1 kW class arcjet thruster was investigated using electrostatic probes of various geometries. The electron number densities and temperatures were determined in a simulated hydrazine plume at axial distances between 3 cm (1.2 in) and 15 cm (5.9 in) and radial distances extending to 10 cm (3.9 in) off centerline. Values of electron number densities obtained using cylindrical and spherical probes of different geometries agreed very well. The electron density on centerline followed a source flow approximation for axial distances as near as 3 cm (1.2 in) from the nozzle exit plane. The model agreed well with previously obtained data in the far field. The effects of propellant mass flow rate and input power level were also studied. Cylindrical probes were used to obtain ion streamlines by changing the probe orientation with respect to the flow. The effects of electrical configuration on the plasma characteristics of the plume were also investigated by using a segmented anode/nozzle thruster. The results showed that the electrical configuration in the nozzle affected the distribution of electrons in the plume.

  15. Mercury's Magnetic Field: Active, Thermoelectric, or Decaying Dynamo or Crustal Remanence? - The MESSENGER Magnetic Field Investigation

    NASA Astrophysics Data System (ADS)

    Lohr, D. A.; Acuna, M. H.; Anderson, B. J.; Korth, H.; Slavin, J. A.; Solomon, S. C.; McNutt, R. L.

    2005-12-01

    The discovery of Mercury's intrinsic magnetic field in 1974 by Mariner 10 was a surprise because the planet's size, thermal state, and angular momentum seemed to rule out the possibility of an active dynamo. Additional encounters of Mercury by the Mariner 10 spacecraft in 1975 confirmed the initial results and allowed the estimation of the planetary magnetic dipole moment to within perhaps a factor of two. This discovery prompted a variety of suggestions for the source of the intrinsic field. The presence of sufficient sulfur in the outer core would allow a thin fluid outer core to persist to the present and perhaps serve as host to a thin-shell dynamo. Recent dynamo simulations under conditions appropriate to Mercury support this possibility and point to aspects of the external field that may be observable from an orbiting spacecraft. Remanent magnetization of the crust and mantle by a now-dead core dynamo field was proposed as an alternative explanation of the Mariner 10 observations in 1976, but this suggestion has been questioned on the grounds that the characteristic time between polarity reversals of a core dynamo field is likely much less than the timescale for acquisition of thermoremanence by the cooling crust and upper mantle. The discovery by Mars Global Surveyor (MGS) in 1997 of an intensely magnetized Martian crust added fuel to this debate, because the Mariner 10 measurements can be reproduced if Mercury's crust is approximated by a magnetized shell having an intrinsic magnetization of the same order of magnitude as that suggested for Mars by the MGS measurements. The MESSENGER magnetic field investigation is designed to address this and other fundamental questions regarding the nature and origin of Mercury's internal field as well as the planet's thermal history. We present here a summary of the MESSENGER magnetic field investigation goals and an assessment of observations acquired during the spacecraft's Earth flyby on 2 August 2005.

  16. FINESSE: Field Investigations to Enable Solar System Science and Exploration

    NASA Technical Reports Server (NTRS)

    Heldmann, Jennifer; Lim, Darlene; Colaprete, Anthony

    2015-01-01

    The FINESSE (Field Investigations to Enable Solar System Science and Exploration) team is focused on a science and exploration field-based research program aimed at generating strategic knowledge in preparation for the human and robotic exploration of the Moon, near-Earth asteroids (NEAs) and Phobos and Deimos. We follow the philosophy that "science enables exploration and exploration enables science." 1) FINESSE Science: Understand the effects of volcanism and impacts as dominant planetary processes on the Moon, NEAs, and Phobos & Deimos. 2) FINESSE Exploration: Understand which exploration concepts of operations (ConOps) and capabilities enable and enhance scientific return. To accomplish these objectives, we are conducting an integrated research program focused on scientifically-driven field exploration at Craters of the Moon National Monument and Preserve in Idaho and at the West Clearwater Lake Impact Structure in northern Canada. Field deployments aimed at reconnaissance geology and data acquisition were conducted in 2014 at Craters of the Moon National Monument and Preserve. Targets for data acquisition included selected sites at Kings Bowl eruptive fissure, lava field and blowout crater, Inferno Chasm vent and outflow channel, North Crater lava flow and Highway lava flow. Field investigation included (1) differential GPS (dGPS) measurements of lava flows, channels (and ejecta block at Kings Bowl); (2) LiDAR imaging of lava flow margins, surfaces and other selected features; (3) digital photographic documentation; (4) sampling for geochemical and petrographic analysis; (5) UAV aerial imagery of Kings Bowl and Inferno Chasm features; and (6) geologic assessment of targets and potential new targets. Over the course of the 5-week field FINESSE campaign to the West Clearwater Impact Structure (WCIS) in 2014, the team focused on several WCIS research topics, including impactites, central uplift formation, the impact-generated hydrothermal system, multichronometer

  17. Human health risk assessment of synthetic turf fields based upon investigation of five fields in Connecticut.

    PubMed

    Ginsberg, Gary; Toal, Brian; Simcox, Nancy; Bracker, Anne; Golembiewski, Brian; Kurland, Tara; Hedman, Curtis

    2011-01-01

    Questions have been raised regarding possible exposures when playing sports on synthetic turf fields cushioned with crumb rubber. Rubber is a complex mixture with some components possessing toxic and carcinogenic properties. Exposure is possible via inhalation, given that chemicals emitted from rubber might end up in the breathing zone of players and these players have high ventilation rates. Previous studies provide useful data but are limited with respect to the variety of fields and scenarios evaluated. The State of Connecticut investigated emissions associated with four outdoor and one indoor synthetic turf field under summer conditions. On-field and background locations were sampled using a variety of stationary and personal samplers. More than 20 chemicals of potential concern (COPC) were found to be above background and possibly field-related on both indoor and outdoor fields. These COPC were entered into separate risk assessments (1) for outdoor and indoor fields and (2) for children and adults. Exposure concentrations were prorated for time spent away from the fields and inhalation rates were adjusted for play activity and for children's greater ventilation than adults. Cancer and noncancer risk levels were at or below de minimis levels of concern. The scenario with the highest exposure was children playing on the indoor field. The acute hazard index (HI) for this scenario approached unity, suggesting a potential concern, although there was great uncertainty with this estimate. The main contributor was benzothiazole, a rubber-related semivolatile organic chemical (SVOC) that was 14-fold higher indoors than outdoors. Based upon these findings, outdoor and indoor synthetic turf fields are not associated with elevated adverse health risks. However, it would be prudent for building operators to provide adequate ventilation to prevent a buildup of rubber-related volatile organic chemicals (VOC) and SVOC at indoor fields. The current results are generally

  18. A Monte Carlo investigation of the Hamiltonian mean field model

    NASA Astrophysics Data System (ADS)

    Pluchino, Alessandro; Andronico, Giuseppe; Rapisarda, Andrea

    2005-04-01

    We present a Monte Carlo numerical investigation of the Hamiltonian mean field (HMF) model. We begin by discussing canonical Metropolis Monte Carlo calculations, in order to check the caloric curve of the HMF model and study finite size effects. In the second part of the paper, we present numerical simulations obtained by means of a modified Monte Carlo procedure with the aim to test the stability of those states at minimum temperature and zero magnetization (homogeneous Quasi stationary states), which exist in the condensed phase of the model just below the critical point. For energy densities smaller than the limiting value U∼0.68, we find that these states are unstable confirming a recent result on the Vlasov stability analysis applied to the HMF model.

  19. Investigations on the Incompletely Developed Plane Diagonal-Tension Field

    NASA Technical Reports Server (NTRS)

    Kuhn, Paul

    1940-01-01

    This report presents the results of an investigation on the incompletely developed diagonal-tension field. Actual diagonal-tension beams work in an intermediate stage between pure shear and pure diagonal tension; the theory developed by wagner for diagonal tension is not directly applicable. The first part of the paper reviews the most essential items of the theory of pure diagonal tension as well as previous attempts to formulate a theory of incomplete diagonal tension. The second part of the paper describes strain measurement made by the N. A. C. A. to obtain the necessary coefficients for the proposed theory. The third part of the paper discusses the stress analysis of diagonal-tension beams by means of the proposed theory.

  20. Investigation of crossed SAW fields by scanning acoustic force microscopy.

    PubMed

    Behme, G; Hesjedal, T

    2001-07-01

    We used multimode scanning acoustic force microscopy (SAFM) for studying noncollinearly propagating Rayleigh and Love wave fields. By analyzing torsion and bending movement of SAFM cantilever, normal and in-plane wave oscillation components are accessible. The SAFM principle is the down-conversion of surface oscillations into cantilever vibrations caused by the nonlinearity of the tip-sample interaction. Through mixing of complementary oscillation components, phase velocities of crossed Rayleigh waves on GaAs and crossed Rayleigh and Love waves on the layered system SiO2/ST-cut quartz were obtained simultaneously. Now, it is possible to investigate elastic properties of submicron areas through multimode SAFM measurements. Finally, we present mixing experiments of four SAWs on GaAs and discuss the various influences on the measured SAFM amplitude and phase contrast.

  1. Investigation of the asymmetric distributions of RF transmission and reception fields at high static field.

    PubMed

    Watanabe, Hidehiro

    2012-01-01

    When radiofrequency (RF) transmission field represents B(1)(+), the reception field represents B(1)(-)*. The distribution of those maps demonstrates asymmetric features at high field magnetic resonance (MR) imaging. Both maps are in mirror symmetry to one another. Almost symmetric distribution of the B(1) field was expected on the laboratory frame in a symmetric sample loaded inside the RF coil designed to achieve a homogeneous B(1) field. Then, a simple change was made in the coordinate transformation equation of RF fields between the rotating and laboratory frames in both linear and quadrature modes to investigate the source of this feature of asymmetry. The magnitude of rotating frame components, B(1)(+) and B(1)(-), consists of the magnitude and the phase difference of the laboratory frame components. The rotating frame components differ in the sign of the sinusoidal phase difference. B(1)(+) is equal to B(1)(-) at lower field because phase changes that depend on position can be ignored. At higher fields, the magnitude component has a symmetric profile, and distribution in the phase component is antisymmetric. Thus, the distributions of B(1)(+) and B(1)(-) maps demonstrate mirror symmetry. Maps of magnitude and phase components were examined in the laboratory frame. Their maps were computed from B(1)(+) and B(1)(-) maps of the human brain and of a spherical saline phantom measured at 4.7T. It was concluded from these analytical and experimental results that the asymmetric and mirror symmetric distributions in B(1)(+) and B(1)(-) are derived from the phase difference in the laboratory frame.

  2. Continuous field investigation assessing nitrogen and phosphorus emission from irrigated paddy field

    NASA Astrophysics Data System (ADS)

    Kogure, Kanami; Aichi, Masaatsu; Zessner, Matthias

    2016-04-01

    In order to maintain good river environment, it is very important to understand and to control nutrient behavior such as Nitrogen and Phosphorus. Other than urban and industrial waste water, nutrient emission from agricultural activity is dominant pollution source into the river system. Rice is one of the staple products of Asia and paddy field occupies large areas in Asian countries. Rice is also widely cultivated in Japan. Paddy field occupies large areas in Japanese river basin areas. While paddy field can deteriorate river water quality by discharging fertilizer, it is also suggested that paddy field has water purification function. Regarding to nutrient emission from paddy field, existing monitored data are insufficient so as to discuss quantitatively seasonal change of material behavior including flooding season and dry season and to evaluate year round comprehensive impact from paddy field to the river system. These are not sufficient data for discussion of material flow and emission impact quantitatively as well as qualitatively. We have carried out field investigation in paddy fields in middle reach of the Tone River Basin. The aim of the survey is understanding of water and nutrient balance in paddy field. In order to understand emission impact from paddy field to river system, all input and output flow are measured to calculate nutrient balance in paddy field. Therefore we observed quantity of water flow into/from paddy field, water quality change of inflow and outflow during flooding season. We set focus on a monitoring paddy field IM, and monitored continuously water and nutrient behavior. By measuring water quality and flow rate of inflow, outflow, infiltrating water, ground water and depth of flooding water, we tried to quantitatively understand N and P cycle around paddy field including seasonal tendency, change accompanying with rainy events and occurred according to agricultural events like fertilization. At the beginning of flooding season, we

  3. Criteria for electric field bioeffects investigations and risk assessment

    SciTech Connect

    Michaelson, S.M.

    1983-01-01

    Most of the research on biological effects of electric fields (EF) has been done with small rodents that have many physical and physiological attributes significantly different from those of man. In making extrapolations from animal data to man we must be particularly cognizant of the limitations and pitfalls in the use of animal experimentation data. Many factors must be considered in the design of experiments using organisms other than man as a test subject. These include the species, strain, sex, age of the animal, the methods of caring for the test animals, the animals' feeding patterns, the roles of seasonal and circadian rhythms, biological drifts, temperature and humidity. The reliability of laboratory studies using experimental animal models depends on the following considerations: (1) the selection of the animal model with consideration of its cognitive limits, (2) scaling factors associated with the nature of the field in the laboratory investigation of the biological processes using animal models, and (3) the methods by which the extrapolation of the data from the animal models relate to human studies.

  4. Scientific investigation plan for initial engineered barrier system field tests

    SciTech Connect

    Wunan Lin

    1993-02-01

    The purpose of this Scientific Investigation Plan (SIP) is to describe tests known as Initial Engineered Barrier System Field Tests (IEBSFT) and identified by Work Breakdown Structure as WBS 1.2.2.2.4. The IEBSFT are precursors to the Engineered Barrier System Field Test (EBSFT), WBS 1.2.2.2.4, to be conducted in the Exploratory Study Facility (ESF) at Yucca Mountain. The EBSFT and IEBSFT are designed to provide information on the interaction between waste packages (simulated by heated containers) and the surrounding rock mass, its vadose water, and infiltrated water. Heater assemblies will be installed in drifts or boreholes openings and heated to measure moisture movement during heat-up and subsequent cool-down of the rock mass. In some of the tests, infiltration of water into the heated rock mass will be studied. Throughout the heating and cooling cycle, instruments installed in the rock will monitor such parameters as temperature, moisture content, concentration of some chemical species, and stress and strain. Rock permeability measurements, rock and fluid (water and gas) sampling, and fracture pattern measurements will also be made before and after the test.

  5. Remedial investigation report for J-Field, Aberdeen Proving Ground, Maryland. Volume 1: Remedial investigation results

    SciTech Connect

    Yuen, C. R.; Martino, L. E.; Biang, R. P.; Chang, Y. S.; Dolak, D.; Van Lonkhuyzen, R. A.; Patton, T. L.; Prasad, S.; Quinn, J.; Rosenblatt, D. H.; Vercellone, J.; Wang, Y. Y.

    2000-03-14

    This report presents the results of the remedial investigation (RI) conducted at J-Field in the Edgewood Area of Aberdeen Proving Ground (APG), a U.S. Army installation located in Harford County, Maryland. Since 1917, activities in the Edgewood Area have included the development, manufacture, and testing of chemical agents and munitions and the subsequent destruction of these materials at J-Field by open burning and open detonation. These activities have raised concerns about environmental contamination at J-Field. This RI was conducted by the Environmental Conservation and Restoration Division, Directorate of Safety, Health and Environmental Division of APG, pursuant to requirements outlined under the Comprehensive Environmental Response, Compensation, and Liability Act, as amended (CERCLA). The RI was accomplished according to the procedures developed by the U.S. Environmental Protection Agency (EPA 1988). The RI provides a comprehensive evaluation of the site conditions, nature of contaminants present, extent of contamination, potential release mechanisms and migration pathways, affected populations, and risks to human health and the environment. This information will be used as the basis for the design and implementation of remedial actions to be performed during the remedial action phase, which will follow the feasibility study (FS) for J-Field.

  6. A field investigation and numerical simulation of coastal fog

    NASA Technical Reports Server (NTRS)

    Mack, E. J.; Eadie, W. J.; Rogers, C. W.; Kocmond, W. C.; Pilie, R. J.

    1973-01-01

    A field investigation of the microphysical and micrometeorological features of fogs occurring near Los Angeles and Vandenberg, California was conducted. Observations of wind speed and direction, temperature, dew point, vertical wind velocity, dew deposition, drop-size distribution, liquid water content, and haze and cloud nucleus concentration were obtained. These observations were initiated in late evening prior to fog formation and continued until the time of dissipation in both advection and radiation fogs. Data were also acquired in one valley fog and several dense haze situations. The behavior of these parameters prior to and during fog are discussed in detail. A two-dimensional numerical model was developed to investigate the formation and dissipation of advection fogs under the influence of horizontal variations in surface temperature. The model predicts the evolution of potential temperature, water vapor content, and liquid water content in a vertical plane as determined by vertical turbulent transfer and horizontal advection. Results are discussed from preliminary numerical experiments on the formation of warm-air advection fog and dissipation by natural and artificial heating from the surface.

  7. Repetitive Behaviours in Typically Developing 2-Year-Olds

    ERIC Educational Resources Information Center

    Leekam, Susan; Tandos, Jonathan; McConachie, Helen; Meins, Elizabeth; Parkinson, Kathryn; Wright, Charlotte; Turner, Michelle; Arnott, Bronia; Vittorini, Lucia; Le Couteur, Ann

    2007-01-01

    Background: Repetitive behaviours are an essential part of the diagnosis of autism but are also commonly seen in typically developing children. The current study investigated the frequency and factor structure of repetitive behaviours in a large community sample of 2-year-olds. Methods: A new measure, the Repetitive Behaviour Questionnaire (RBQ-2)…

  8. Combining Dedicated Online Training and Apprenticeships in the Field to Assist in Professionalization of Humanitarian Aid Workers: a 2-year Pilot Project for Anesthesia and Intensive Care Residents Working in Resource Constrained and Low-income Countries

    PubMed Central

    Foletti, Marco; Ingrassia, Pier Luigi; Ragazzoni, Luca; Djalali, Ahmadreza; Ripoll Gallardo, Alba; Burkle, Frederick M.; Della Corte, Francesco

    2014-01-01

    Introduction: As a result of the gaps in humanitarian response highlighted by several reports, the international community called for an increased professionalization of humanitarian aid workers. This paper describes a pilot project by an Italian university and a non-profit, non-governmental organization to implement a medical apprenticeship in low-income countries during Anesthesia and Intensive Care Medicine residencies. Methods: Before deployment, participants were required to complete a dedicated online training course about safety and security in the field, principles of anesthesia at the district hospital level, emergency and essential surgical care, essentials of medical treatment in resource-constrained environments and psychological support in emergencies. Results: At the end of the program, a qualitative self-evaluation questionnaire administered to participants highlighted how the project allowed the participants to advance their professional skills when working in a low-resource environment, while also mastering their adapting skills and the ability to interact and cooperate with local healthcare personnel. The project also proved to be a means for personal growth, making these experiences a recommendation for all residents as a necessary step for the professionalization of healthcare personnel involved in humanitarian aid. PMID:25642362

  9. First results of the MAVEN magnetic field investigation

    NASA Astrophysics Data System (ADS)

    Connerney, J. E. P.; Espley, J. R.; DiBraccio, G. A.; Gruesbeck, J. R.; Oliversen, R. J.; Mitchell, D. L.; Halekas, J.; Mazelle, C.; Brain, D.; Jakosky, B. M.

    2015-11-01

    Two Mars Atmosphere and Volatile EvolutioN magnetic field sensors sample the ambient magnetic field at the outer edge of each solar array. We characterized relatively minor spacecraft-generated magnetic fields using in-flight subsystem tests and spacecraft maneuvers. Dynamic spacecraft fields associated with the power subsystem (≤1 nT) are compensated for using spacecraft engineering telemetry to identify active solar array circuits and monitor their electrical current production. Static spacecraft magnetic fields are monitored using spacecraft roll maneuvers. Accuracy of measurement of the environmental magnetic field is demonstrated by comparison with field directions deduced from the symmetry properties of the electron distribution function measured by the Solar Wind Electron Analyzer. We map the bow shock, magnetic pileup boundary, the V × B convection electric field and ubiquitous proton cyclotron, and 1 Hz waves in the ion foreshock region.

  10. Field site investigation: Effect of mine seismicity on groundwater hydrology

    SciTech Connect

    Ofoegbu, G.I.; Hsiung, S.; Chowdhury, A.H.; Philip, J.

    1995-04-01

    The results of a field investigation on the groundwater-hydrologic effect of mining-induced earthquakes are presented in this report. The investigation was conducted at the Lucky Friday Mine, a silver-lead-zinc mine in the Coeur d`Alene Mining District of Idaho. The groundwater pressure in sections of three fracture zones beneath the water table was monitored over a 24-mo period. The fracture zones were accessed through a 360-m-long inclined borehole, drilled from the 5,700 level station of the mine. The magnitude, source location, and associated ground motions of mining-induced seismic events were also monitored during the same period, using an existing seismic instrumentation network for the mine, augmented with additional instruments installed specifically for the project by the center for Nuclear Waste Regulatory Analyses (CNWRA). More than 50 seismic events of Richter magnitude 1.0 or larger occurred during the monitoring period. Several of these events caused the groundwater pressure to increase, whereas a few caused it to decrease. Generally, the groundwater pressure increased as the magnitude of seismic event increased; for an event of a given magnitude, the groundwater pressure increased by a smaller amount as the distance of the observation point from the source of the event increased. The data was examined using regression analysis. Based on these results, it is suggested that the effect of earthquakes on groundwater flow may be better understood through mechanistic modeling. The mechanical processes and material behavior that would need to be incorporated in such a model are examined. They include a description of the effect of stress change on the permeability and water storage capacity of a fracture rock mass; transient fluid flow; and the generation and transmission of seismic waves through the rock mass.

  11. Theoretical investigation of bacteria polarizability under direct current electric fields.

    PubMed

    Dingari, Naga Neehar; Buie, Cullen R

    2014-04-22

    We present a theoretical model to investigate the influence of soft polyelectrolyte layers on bacteria polarizability. We resolve soft-layer electrokinetics by considering the pH-dependent dissociation of ionogenic groups and specific interactions of ionogenic groups with the bulk electrolyte to go beyond approximating soft-layer electrokinetics as surface conduction. We model the electrokinetics around a soft particle by modified Poisson-Nernst-Planck equations (PNP) to account for the effects of ion transport in the soft layer and electric double layer. Fluid flow is modeled by modified Stokes equations accounting for soft-layer permeability. Two test cases are presented to demonstrate our model: fibrillated and unfibrillated Streptococcus salivarius bacteria. We show that electrolytic and pH conditions significantly influence the extent of soft-particle polarizability in dc fields. Comparison with an approximate analytical model based on Dukhin-Shilov theory for soft particles shows the importance of resolving soft-layer electrokinetics. Insights from this study can be useful in understanding the parameters that influence soft-particle dielectrophoresis in lab-on-a-chip devices.

  12. Limited field investigation for the 200-UP-1 operable unit

    SciTech Connect

    1996-11-01

    The 200-UP-1 Groundwater Operable Unit is located in the southern portion of the 200 West Area on the Hanford Site in Washington State. The operable unit is located adjacent to the 200-ZP-1 Groundwater Operable Unit and underlies a significant part of seven source operable units: 200-RO-1, 200-RO-2, 200-RO-3, 200-RO-4, 200-SS-2, 200-UP-2, and 200-UP-3. Remedial efforts in the 100-ZP-1 Operable Unit focus on addressing volatile organic contamination in the aquifer. The focus of the 200-UP-1 limited field investigation (LFI) is on contaminated aquifer soils and groundwater within its boundary, with the exception of uranium and technetium-99 plumes, which are addressed by an existing 200-UP-1 interim remedial measure (IRM). The LFI approach is driven by general and specific data needs required to refine the site conceptual model and conduct a risk assessment. Activities supporting the LFI include drilling, well construction, sampling and analysis, data validation, geologic and geophysical logging, aquifer testing, measuring depth to water, and evaluating geodetic survey and existing analytical data.

  13. Magnetic field profile analysis for gyrotron experimental investigation

    NASA Astrophysics Data System (ADS)

    Pagonakis, Ioannis Gr.; Avramidis, Konstantinos A.; Gantenbein, Gerd; Rzesnicki, Tomasz; Samartsev, Andrey; Jelonnek, John

    2017-03-01

    The external applied magnetic field plays a main role on the gyrotron operation. Even if the gyrotron design is optimized for the nominal magnetic profile, it is possible the performance to be better for an alternative one. This unexpected result can happen for several reasons, such as the manufacturing imperfections, the misalignment issues, and several unknown factors in gyrotron theory and design. The systematic experimental investigation of the gyrotron in different magnetic profiles is very important for the optimization of the gyrotron operation and for the better understanding of the gyrotron behavior. In this sense, an analytical approach for the definition of the appropriate magnetic profiles based on the beam characteristics instead of the coil currents definition is proposed for a systematic experimental study. Using this technique, operational maps in the space of the important magnetic profile parameters are developed, which are very useful for the characterization of the gyrotron performance. For the demonstration of this idea, the operational maps of the short-pulse prototype of the 170 GHz, 1 MW European ITER gyrotron project are presented.

  14. Results of investigations at the Ahuachapan geothermal field, El Salvador

    SciTech Connect

    Dennis, B.; Goff, F.; Van Eeckhout, E.; Hanold, B.

    1990-04-01

    Well logging operations were performed in eight of the geothermal wells at Ahuachapan. High-temperature downhole instruments, including a temperature/rabbit, caliper, fluid velocity spinner/temperature/pressure (STP), and fluid sampler, were deployed in each well. The caliper tool was used primarily to determine if chemical deposits were present in well casings or liners and to investigate a suspected break in the casing in one well. STP logs were obtained from six of the eight wells at various flow rates ranging from 30 to 80 kg/s. A static STP log was also run with the wells shut-in to provide data to be used in the thermodynamic analysis of several production wells. The geochemical data obtained show a system configuration like that proposed by C. Laky and associates in 1989. Our data indicate recharge to the system from the volcanic highlands south of the field. Additionally, our data indicate encroachment of dilute fluids into deeper production zones because of overproduction. 17 refs., 50 figs., 10 tabs.

  15. Electrophoretic field gradient focusing: an investigation of the experimental parameters.

    PubMed

    Tuñón, Pilar González; Wang, Yating; Myers, Peter; Bartle, Keith D; Bowhill, Larry; Ivory, Cornelius F; Ansell, Richard J

    2008-01-01

    Electrophoretic field gradient focusing has been used to separate the two oxidation states of myoglobin (Mb), and to separate Mb from bromophenol blue (BPB). Polyacrylamide and Sephadex were shown to be suitable packing materials whilst silica led to band broadening with Mb. BPB and Mb could be simultaneously focused apart using either a fixed 21-electrode setup or a dynamic 6-electrode setup. Using a dynamic three-electrode setup either analyte could be focused but not both simultaneously. It was shown that a higher ionic strength buffer in the separation channel compared to the coolant channel enhanced focusing between electrodes due to a conductivity gradient. Different running buffers were investigated and it was found that using a pH 8.6 buffer containing N,N,N-tris(hydroxymethyl)aminomethane (Tris) and phosphate ions the oxidation states of Mb could be separated but the separation of Mb from BPB was not as good as would be hoped for. Using a pH 8.6 buffer containing Tris, N-2-hydroxyethylpiperazine-N'-3-propanesulphonate and chloride ions as running buffer, BPB and Mb could be well separated but the two oxidation states of Mb merged.

  16. Near-field scanning optical microscopy investigations of conjugated polymers

    NASA Astrophysics Data System (ADS)

    Dearo, Jessie Ann

    The Near-Field Scanning Optical Microscopy (NSOM) studies of novel, optically active, conjugated polymers are presented. NSOM is a relatively new technique which produces super resolution (˜50--100 nm) optical images simultaneously with topography. The conjugated polymer poly(p-phenylene vinylene) (PPV) and derivatives of PPV are organic semiconductor-like materials with interesting and unique optical properties. Derivatives of PPV have been used in LEDs and have potential in other optoelectronic devices. NSOM provides a tool for investigation of the photoluminescence, absorption/reflection, photo-dynamics and photoconductivity of films of PPV and PPV derivatives on the length scale that these properties are fundamentally defined. The NSOM experiments have revealed mesoscale domains (˜100 nm) of varying photoluminescence emission and average molecular order in drop cast films of PPV. NSOM of stretch-oriented PPV have shown domains of perpendicular molecular orientation with low photoluminescence emission. Near-field photoconductivity experiments of stretch-oriented PPV have correlated the mesoscale topography with the photoconductivity properties of the polymer. NSOM experiments of films of poly(2-methoxy, 5-(2'-(ethyl(hexyloxy)-p-phenylene vinylene) (MEH-PPV) have shown that there is mesoscale spatial inhomogeneity in the photo-oxidation process which reduces photoluminescence emission. NSOM has also been used to create nanoscale photo-patterning in MEH-PPV films. The NSOM experiments of blended films of MEH-PPV in polystyrene have shown mesoscale phase separation directly correlated to variations in the optical properties of the film. Derivatives of PPV, stretch-oriented in polyethylene, show photoluminescence intensity variations perpendicular and parallel to the stretch-direction correlated to topography features. As a complement to the NSOM studies of conjugated polymers, single polymer molecule experiments of MEH-PPV are also presented. The

  17. AGU awarded grant to establish program on engaging 2-year-college students in research

    NASA Astrophysics Data System (ADS)

    Asher, Pranoti; Adamec, Bethany Holm

    2012-03-01

    Students at 2-year colleges are a critical part of the future Earth and space science workforce, and undergraduate research experiences provide a hook to retain and ultimately to graduate students in the field. AGU was awarded a planning grant by the U.S. National Science Foundation Directorate for Geosciences (Opportunities for Enhancing Diversity in the Geosciences award 1201578) to help launch a new initiative concerning these issues; education and public outreach staff are the principal investigators. This new initiative, titled Unique Research Experiences for Two-Year College Faculty and Students (URECAS), will begin with a planning workshop this summer (11-13 July). The workshop will bring together faculty from 2-year colleges, 4-year colleges and universities, and representatives from professional societies and federal organizations to learn more about how to support 2-year-college faculty and students engaged in Earth and space science research and to discuss the development of a program to strengthen the role of 2-year-college Earth and space science students in the future workforce

  18. Field and Laboratory Investigations of Organic Photochemistry on Urban Surfaces

    NASA Astrophysics Data System (ADS)

    Styler, S. A.; Baergen, A.; van Pinxteren, D.; Donaldson, D. J.; Herrmann, H.

    2014-12-01

    In polluted urban environments, windows and building surfaces rapidly become coated with a complex film of chemicals, which enhances the dry deposition of particles and the partitioning of semi-volatile organic species to the surface. Despite its high surface-to-volume ratio and direct exposure to sunlight, few studies have directly investigated the role that this "urban film" may play in promoting the photooxidative processing of semi-volatile organics contained within it. The present study represents a comprehensive field- and laboratory-based investigation of the film-phase photochemistry of polycyclic aromatic hydrocarbons (PAH), here used as proxies for light-absorbing semi-volatile organics present within the film. Urban film sampling was conducted using a custom-built three-stage sampler housing, which was deployed in a central, high-traffic area in Leipzig, Germany. The sampler itself employs small glass beads as surrogate window surfaces and is designed such that only its uppermost stage is exposed to sunlight. Each stage is subdivided into 16 compartments, which allows for the study of film formation and evolution. In the first phase of the study, the role of urban film as a photochemical sink for reactive organic species was determined by measuring total film PAH content and PAH abundance ratios as a function of atmospheric exposure time under both light and dark conditions. In the second, more general, phase of the study, the organic and inorganic composition of collected film samples was compared to that of co-located PM10 samples, and differences between the two sample types were used to gain insight into the relative importance of heterogeneous photochemical oxidation within the particle and film phases. In the third phase of the study, film samples grown under dark conditions were exposed to gas-phase ozone in an atmospheric-pressure flat-bed reactor, and the kinetics of ozone-induced PAH loss were studied under both dark and illuminated conditions

  19. Regional Ecorisk Field investigation, upper Clark Fork River Basin

    SciTech Connect

    Pastorok, R.; LaTier, A.; Ginn, T.

    1995-12-31

    The Regional Ecorisk Field Investigation was conducted at the Clark Fork River Superfund Site (Montana) to evaluate the relationships between plant communities and tailings deposits in riparian habitats and to evaluate food-chain transfer of trace elements to selected wildlife species. Stations were selected to represent a range of vegetation biomass (or cover) values and apparent impact of trace elements, with some areas of lush vegetation, some areas of mostly unvegetated soil (e.g., < 30 percent plant cover), and a gradient in between. For the evaluation of risk to wildlife, bioaccumulation of metals was evaluated in native or naturalized plants, terrestrial invertebrates, and the deer mouse (Peromyscus maniculatus). Potential reproductive effects in the deer mouse were evaluated by direct measurements. For other wildlife species, bioaccumulation data were interpreted in the context of food web exposure models. Total biomass and species richness of riparian plant communities are related to tailings content of soil as indicated by pH and metals concentrations. Risk to populations of omnivorous small mammals such as the deer mouse was not significant. Relative abundance and reproductive condition of the deer mouse were normal, even in areas of high metals enrichment. Based on exposure models and site-specific tissue residue data for dietary species, risk to local populations of predators such as red fox and American kestrel that feed on deer mice and terrestrial invertebrates is not significant. Risk to herbivores related to metals bioaccumulation in plant tissues is not significant. Population level effects in deer and other large wildlife are not expected because of the large home ranges of such species and compensatory demographic factors.

  20. First Results of the MAVEN Magnetic Field Investigation

    NASA Astrophysics Data System (ADS)

    Connerney, J. E. P.; Espley, J. R.; DiBraccio, G. A.; Gruesbeck, J.; Mitchell, D. L.; Halekas, J. S.; Mazelle, C. X.; Brain, D.; Jakosky, B. M.; Oliversen, R. J.

    2015-12-01

    The MAVEN spacecraft approaches the end of its first year in orbit, systematically mapping the interaction region about Mars with a focus on atmospheric escape. The comprehensive instrument suite aboard MAVEN has busied itself in mapping the magnetosphere, magnetosheath, magnetotail, and extended atmospheric corona in near-Mars space. MAVEN carries two magnetic field sensors (fluxgate magnetometers) as part of the particles and fields package (PFP); they sample the ambient magnetic field from a vantage point on at the outer edge of each solar array. We characterized relatively minor spacecraft-generated magnetic fields using a series of in-flight subsystem tests and spacecraft maneuvers. Dynamic spacecraft fields (≤ 1 nT) associated with the operation of specific solar array circuits are compensated for using spacecraft engineering telemetry to identify active circuits and monitor their electrical current production. Static spacecraft magnetic fields are monitored using spacecraft roll maneuvers. Accuracy of measurement of the environmental magnetic field is demonstrated by comparison with field directions deduced from the symmetry properties of the electron distribution function measured by the Solar Wind Electron Analyzer (SWEA). We compile magnetometer observations to characterize intense crustal magnetic fields, the solar wind interaction with Mars, and ubiquitous proton cyclotron and 1-Hz waves in the upstream solar wind (ion foreshock region). The figure below compiles observations of magnetic fluctuations obtained by MAVEN in near-Mars space. The map of magnetic fluctuations reveals the statistical extent of the magnetosheath, confined between the bow shock and the magnetic pile-up region.

  1. Laboratory and field investigations of marsh edge erosion

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This chapter presents the laboratory experiments and field observations of marsh edge erosion. The marsh retreat rate in a field study site in Terrebonne Bay, Louisiana, was measured using GPS systems and aerial photographs. The wave environment was also measured in order to correlate the marsh edge...

  2. 77 FR 16852 - Notice of Reclassification of Five Regional Offices to Investigative Field Offices: Seattle, WA...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-22

    ... URBAN DEVELOPMENT Notice of Reclassification of Five Regional Offices to Investigative Field Offices... Field Offices: Louisville, KY and Jacksonville, FL; and Closure of Two Sub- Field Offices: Long Island... offices as field offices of investigation and the closing of the Louisville, Kentucky and...

  3. Policy Forum: Studying Eyewitness Investigations in the Field

    PubMed Central

    Dawes, Robyn; Jacoby, Larry L.; Kahneman, Daniel; Lempert, Richard; Roediger, Henry L.; Rosenthal, Robert

    2007-01-01

    This article considers methodological issues arising from recent efforts to provide field tests of eyewitness identification procedures. We focus in particular on a field study (Mecklenburg 2006) that examined the “double blind, sequential” technique, and consider the implications of an acknowledged methodological confound in the study. We explain why the confound has severe consequences for assessing the real-world implications of this study. PMID:17610149

  4. Investigation of Reddening in Fields of the SMASH Survey

    NASA Astrophysics Data System (ADS)

    Juelfs, Elizabeth A.; Olsen, Knut A.; SMASH Team

    2016-01-01

    We present dust extinction maps derived from eight fields in the Survey of the MAgellanic Stellar History (SMASH), a survey that is imaging 480 deg^2 of the southern sky in DES-ugriz with the CTIO 4-m Blanco telescope and the Dark Energy Camera (DECam). We derive the extinction due to dust using fits to the stellar locus of stars brighter than g=21 in color-color diagrams, and explore the spatial distribution of the extinction within each of the fields. We compare our results to the extinction map of Schlegel, Finkbeiner, & Davis (1998), and find generally good agreement. We describe plans to measure the three-dimensional distribution of extinction in these fields using fainter stars and background galaxies as tracers. Juelfs was supported by the NOAO/KPNO Research Experiences for Undergraduates (REU) Program which is funded by the National Science Foundation Research Experiences for Undergraduates Program (AST-1262829).

  5. Magnetic field investigations during ROSETTA's 2867 Šteins flyby

    NASA Astrophysics Data System (ADS)

    Auster, H. U.; Richter, I.; Glassmeier, K. H.; Berghofer, G.; Carr, C. M.; Motschmann, U.

    2010-07-01

    During the 2867 Šteins flyby of the ROSETTA spacecraft on September 5, 2008 magnetic field measurements have been made with both the RPC orbiter magnetometer and the ROMAP lander magnetometer. These combined magnetic field measurements allow a detailed examination of any magnetic signatures caused either directly by the asteroid or indirectly by Šteins' different modes of interaction with the solar wind. Comparing measurements with simulation results show that Šteins does not posses a significant remanent magnetization. The magnetization is estimated at less than 10 -3 A m 2/kg. This is significantly different from results at 9969 Braille and 951 Gaspra.

  6. Extending methods: using Bourdieu's field analysis to further investigate taste

    NASA Astrophysics Data System (ADS)

    Schindel Dimick, Alexandra

    2015-06-01

    In this commentary on Per Anderhag, Per-Olof Wickman and Karim Hamza's article Signs of taste for science, I consider how their study is situated within the concern for the role of science education in the social and cultural production of inequality. Their article provides a finely detailed methodology for analyzing the constitution of taste within science education classrooms. Nevertheless, because the authors' socially situated methodology draws upon Bourdieu's theories, it seems equally important to extend these methods to consider how and why students make particular distinctions within a relational context—a key aspect of Bourdieu's theory of cultural production. By situating the constitution of taste within Bourdieu's field analysis, researchers can explore the ways in which students' tastes and social positionings are established and transformed through time, space, place, and their ability to navigate the field. I describe the process of field analysis in relation to the authors' paper and suggest that combining the authors' methods with a field analysis can provide a strong methodological and analytical framework in which theory and methods combine to create a detailed understanding of students' interest in relation to their context.

  7. Investigating completion strategies; Cormorant Field, U. K. North Sea

    SciTech Connect

    Stiles, J.H. Jr. ); Valenti, N.P. )

    1990-03-01

    This paper describes studies that evaluate various completion strategies for new subsea wells in the Cormorant field, U.K. North Sea. These studies, which complement work done by the field operator, include detailed reservoir description work to define oil-in-place (OIP) and permeability distribution and a waterflood simulation for a representative reservoir cross section. Wellbore, flowline, and pipeline hydraulics for the complex production/injection system are included to model well rates more accurately. The results provide general insight into the nature of displacement during waterflooding of a stratified section with a limited number of wells. They also provide specific guidance on dual vs. single completions; perforating, testing, and stimulation sequence; and the benefits of partially perforating high-permeability sands.

  8. Investigation of RF Emissions from Electric Field Dominated Plasmas

    DTIC Science & Technology

    1989-03-31

    Equilibrium and Force 3 Balance in Electric Field Dominated Plasmas". This paper brought to bear experimental evidence that macroscopic stability of electric...continuity-equation oscillation has been recognized in standard monographs and compilations such as A. I. Akhiezer et 5al. Plasma Electrodynamics , and F...has been recognized in standard monographs and compilations such as A. I. Akhiezer et al. Plasma Electrodynamics , and F. Cap’s Handbook on Plasma

  9. Structural investigations of Great Basin geothermal fields: Applications and implications

    SciTech Connect

    Faulds, James E; Hinz, Nicholas H.; Coolbaugh, Mark F

    2010-11-01

    Because fractures and faults are commonly the primary pathway for deeply circulating hydrothermal fluids, structural studies are critical to assessing geothermal systems and selecting drilling targets for geothermal wells. Important tools for structural analysis include detailed geologic mapping, kinematic analysis of faults, and estimations of stress orientations. Structural assessments are especially useful for evaluating geothermal fields in the Great Basin of the western USA, where regional extension and transtension combine with high heat flow to generate abundant geothermal activity in regions having little recent volcanic activity. The northwestern Great Basin is one of the most geothermally active areas in the USA. The prolific geothermal activity is probably due to enhanced dilation on N- to NNE-striking normal faults induced by a transfer of NW-directed dextral shear from the Walker Lane to NW-directed extension. Analysis of several geothermal fields suggests that most systems occupy discrete steps in normal fault zones or lie in belts of intersecting, overlapping, and/or terminating faults. Most fields are associated with steeply dipping faults and, in many cases, with Quaternary faults. The structural settings favoring geothermal activity are characterized by subvertical conduits of highly fractured rock along fault zones oriented approximately perpendicular to the WNW-trending least principal stress. Features indicative of these settings that may be helpful in guiding exploration for geothermal resources include major steps in normal faults, interbasinal highs, groups of relatively low discontinuous ridges, and lateral jogs or terminations of mountain ranges.

  10. Echoes from the Field: An Ethnographic Investigation of Outdoor Science Field Trips

    ERIC Educational Resources Information Center

    Boxerman, Jonathan Zvi

    2013-01-01

    As popular as field trips are, one might think they have been well-studied. Nonetheless, field trips have not been heavily studied, and little research has mapped what actually transpires during field trips. Accordingly, to address this research gap, I asked two related research questions. The first question is a descriptive one: What happens on…

  11. ASTEROSEISMIC INVESTIGATION OF KNOWN PLANET HOSTS IN THE KEPLER FIELD

    SciTech Connect

    Christensen-Dalsgaard, J.; Kjeldsen, H.; Arentoft, T.; Frandsen, S.; Quirion, P.-O.; Brown, T. M.; Gilliland, R. L.; Borucki, W. J.; Koch, D.; Jenkins, J. M.

    2010-04-20

    In addition to its great potential for characterizing extra-solar planetary systems, the Kepler Mission is providing unique data on stellar oscillations. A key aspect of Kepler asteroseismology is the application to solar-like oscillations of main-sequence stars. As an example, we here consider an initial analysis of data for three stars in the Kepler field for which planetary transits were known from ground-based observations. For one of these, HAT-P-7, we obtain a detailed frequency spectrum and hence strong constraints on the stellar properties. The remaining two stars show definite evidence for solar-like oscillations, yielding a preliminary estimate of their mean densities.

  12. Spectral investigation of nonlinear local field effects in Ag nanoparticles

    SciTech Connect

    Sato, Rodrigo Takeda, Yoshihiko; Ohnuma, Masato; Oyoshi, Keiji

    2015-03-21

    The capability of Ag nanoparticles to modulate their optical resonance condition, by optical nonlinearity, without an external feedback system was experimentally demonstrated. These optical nonlinearities were studied in the vicinity of the localized surface plasmon resonance (LSPR), using femtosecond pump-and-probe spectroscopy with a white-light continuum probe. Transient transmission changes ΔT/T exhibited strong photon energy and particle size dependence and showed a complex and non-monotonic change with increasing pump light intensity. Peak position and change of sign redshift with increasing pump light intensity demonstrate the modulation of the LSPR. These features are discussed in terms of the intrinsic feedback via local field enhancement.

  13. Investigation of nanogap localized field enhancement in gold plasmonic structures

    NASA Astrophysics Data System (ADS)

    Debu, Desalegn Tadesse; Bauman, Stephen; Saylor, Cameron; Novak, Eric; French, David; Herzog, Joseph

    2015-03-01

    Nanogaps between plasmonic structures allow confining the localized electric field with moreenhancements. Based on previously implemented two-step lithography process, we introducea nano-masking technique to fabricate nanostructrues and nanogaps for various geometrical patterns. This new method can fabricate gold nanostructures as well as nanogaps that are less than 10nm, below the limiting scale of lithography. Simulation from finite element method (FEM) shows strong gap dependence of optical properties and peak enhancement of these devices. The fabricated plasmonic nanostructure provides wide range of potential future application including highly sensitive optical antenna, surface enhanced Raman spectroscopy and biosensing.

  14. A Field Course Investigation of a Pembrokeshire River.

    ERIC Educational Resources Information Center

    Bailey, R. G.

    1978-01-01

    The river was investigated at six stations from source to estuary. Modifications of water quality and aquatic communities are related to man's activities in the river basin. The organization of the exercise and the method employed are described. (Author/BB)

  15. Field Dependence/Independence Cognitive Style and Problem Posing: An Investigation with Sixth Grade Students

    ERIC Educational Resources Information Center

    Nicolaou, Aristoklis Andreas; Xistouri, Xenia

    2011-01-01

    Field dependence/independence cognitive style was found to relate to general academic achievement and specific areas of mathematics; in the majority of studies, field-independent students were found to be superior to field-dependent students. The present study investigated the relationship between field dependence/independence cognitive style and…

  16. First Investigation on the Radiation Field of the Spherical Hohlraum.

    PubMed

    Huo, Wen Yi; Li, Zhichao; Chen, Yao-Hua; Xie, Xuefei; Lan, Ke; Liu, Jie; Ren, Guoli; Li, Yongsheng; Liu, Yonggang; Jiang, Xiaohua; Yang, Dong; Li, Sanwei; Guo, Liang; Zhang, Huan; Hou, Lifei; Du, Huabing; Peng, Xiaoshi; Xu, Tao; Li, Chaoguang; Zhan, Xiayu; Yuan, Guanghui; Zhang, Haijun; Jiang, Baibin; Huang, Lizhen; Du, Kai; Zhao, Runchang; Li, Ping; Wang, Wei; Su, Jingqin; Ding, Yongkun; He, Xian-Tu; Zhang, Weiyan

    2016-07-08

    The first spherical hohlraum energetics experiment is accomplished on the SGIII-prototype laser facility. In the experiment, the radiation temperature is measured by using an array of flat-response x-ray detectors (FXRDs) through a laser entrance hole at four different angles. The radiation temperature and M-band fraction inside the hohlraum are determined by the shock wave technique. The experimental observations indicate that the radiation temperatures measured by the FXRDs depend on the observation angles and are related to the view field. According to the experimental results, the conversion efficiency of the vacuum spherical hohlraum is in the range from 60% to 80%. Although this conversion efficiency is less than the conversion efficiency of the near vacuum hohlraum on the National Ignition Facility, it is consistent with that of the cylindrical hohlraums used on the NOVA and the SGIII-prototype at the same energy scale.

  17. First Investigation on the Radiation Field of the Spherical Hohlraum

    NASA Astrophysics Data System (ADS)

    Huo, Wen Yi; Li, Zhichao; Chen, Yao-Hua; Xie, Xuefei; Lan, Ke; Liu, Jie; Ren, Guoli; Li, Yongsheng; Liu, Yonggang; Jiang, Xiaohua; Yang, Dong; Li, Sanwei; Guo, Liang; Zhang, Huan; Hou, Lifei; Du, Huabing; Peng, Xiaoshi; Xu, Tao; Li, Chaoguang; Zhan, Xiayu; Yuan, Guanghui; Zhang, Haijun; Jiang, Baibin; Huang, Lizhen; Du, Kai; Zhao, Runchang; Li, Ping; Wang, Wei; Su, Jingqin; Ding, Yongkun; He, Xian-Tu; Zhang, Weiyan

    2016-07-01

    The first spherical hohlraum energetics experiment is accomplished on the SGIII-prototype laser facility. In the experiment, the radiation temperature is measured by using an array of flat-response x-ray detectors (FXRDs) through a laser entrance hole at four different angles. The radiation temperature and M -band fraction inside the hohlraum are determined by the shock wave technique. The experimental observations indicate that the radiation temperatures measured by the FXRDs depend on the observation angles and are related to the view field. According to the experimental results, the conversion efficiency of the vacuum spherical hohlraum is in the range from 60% to 80%. Although this conversion efficiency is less than the conversion efficiency of the near vacuum hohlraum on the National Ignition Facility, it is consistent with that of the cylindrical hohlraums used on the NOVA and the SGIII-prototype at the same energy scale.

  18. Results of investigation at the Ahuachapan Geothermal Field, El Salvador

    SciTech Connect

    Fink, J.B. )

    1990-04-01

    The Ahuachapan Geothermal Field (AGF) is a 95 megawatt geothemal-sourced power-plant operated by the Comision Ejecutiva Hidroelectrica del Rio Lempa (CEL) of El Salvador. During the past decade, as part of an effort to increase in situ thermal reserves in order to realize the full generation capacity of the AGF, extensive surface geophysical coverage has been obtained over the AGF and the prospective Chipilapa area to the east. The geophysical surveys were performed to determine physical property characteristics of the known reservoir and then to search for similar characteristics in the Chipilapa area. A secondary objective was to evaluate the surface recharge area in the highlands to the south of the AGF. The principal surface electrical geophysical methods used during this period were DC resistivity and magnetotellurics. Three available data sets have been reinterpreted using drillhole control to help form geophysical models of the area. The geophysical models are compared with the geologic interpretations.

  19. Investigation of the temperature field in a turbulent boundary layer

    NASA Astrophysics Data System (ADS)

    Byers, Clayton; Hultmark, Marcus

    2015-11-01

    The scaling and evolution of a developing turbulent thermal boundary layer is investigated. By allowing the temperature differences in the fluid to remain small enough to treat temperature as a passive scalar, the analysis can be extended to any turbulent convection/diffusion problem. Mean temperature scaling is developed and analyzed by utilizing the ``Asymptotic Invariance Principle'' developed by George and Castillo (1997). Possible effects of the Reynolds and Prandtl number are discussed. The derived power law solution for the inner and outer scaling is then used to develop a ``heat transfer law'' for the wall heat flux, qw. Data collection is performed with a newly developed MEMS sensor, allowing improved performance and reduced spatial and temporal filtering of the signal. Integration with a PIV system will allow direct measurements of the turbulent heat flux - θv to investigate the extent of the overlap layer and validity of the proposed scaling laws. Temperature variance 1/2 θ2 will also be investigated, with a possible scaling proposed.

  20. Infantile Amnesia across the Years: A 2-Year Follow-Up of Children's Earliest Memories

    ERIC Educational Resources Information Center

    Peterson, Carole; Warren, Kelly L.; Short, Megan M.

    2011-01-01

    Although infantile amnesia has been investigated for many years in adults, only recently has it been investigated in children. This study was a 2-year follow-up and extension of an earlier study. Children (4-13 years old) were asked initially and 2 years later for their earliest 3 memories. At follow-up, their age at the time of these memories…

  1. Soil water flow dynamics in a managed cutover peat field, Quebec: Field and laboratory investigations

    NASA Astrophysics Data System (ADS)

    Schlotzhauer, Susanne M.; Price, Jonathan S.

    1999-12-01

    In this paper concerned with soil water dynamics in a managed cutover peat field, the microscale hydrological processes and parameters governing water flow and storage through variably saturated peat are investigated. An open water ditch-reservoir enhanced wetting of adjacent cutover peat, maintaining the water table depth above 43 cm during the summer, surface soil moisture above 45%, and water tension in the surface layer above -45 mbar. Desaturation of pores was noted in the -2 and -10 cm depths, but at -30 and -50 cm a decrease in moisture content of several percent was associated with compression of the peat as the water table dropped. Air entry occurred only at pressures below -15 mbar. Seasonal subsidence resulted in cumulative vertical displacement in excess of 10 cm during the study period. Typical settlements in the peat ranged between 11 and 23% of the lowering of the water table. Considerable hysteresis was observed, and vertical displacement was 5 times greater in response to water loss, compared to rewetting. The specific storage (Ss) in the 180 cm thick deposit averaged 9.4 × 10-4 cm-1 during drying periods but averaged only 2.6 × 10-4 cm-1 on rewetting.Ss was more important than specific yield (Sy) in the overall aquifer storativity. Transient hydraulic properties resulted from the shifting soil structure. The increase in peat bulk density caused by drying increased the water retention capacity and decreased hydraulic conductivity. Mean saturated hydraulic conductivity was 15 cm d-1 and decreased 2 orders of magnitude as the degree of saturation dropped from 1 to 0.4. The horizontal/vertical anisotropy ratio was 4. The changing surface elevation in response to seasonal subsidence had a profound influence on the nature of the storage changes and hydraulic parameters of the peat soil.

  2. Field investigation of FGD system chemistry. Final report

    SciTech Connect

    Litherland, S.T.; Colley, J.D.; Glover, R.L.; Maller, G.; Behrens, G.P.

    1984-12-01

    Three full-scale wet limestone FGD systems were investigated to gain a better understanding of FGD system operation and chemistry. The three plants which participated in the program were South Mississippi Electric Power Association's R. D. Morrow Station, Colorado-Ute Electric Association's Craig Station, and Central Illinois Light Company's Duck Creek Station. Each FGD system was characterized with respect to SO/sub 2/ removal, liquid and solid phase chemistry, and calcium sulfite and calcium sulfate relative saturation. Mist eliminator chemistry and performance were documented at Morrow and Duck Creek. Solutions to severe mist eliminator scaling and pluggage were demonstrated at Duck Creek. A technical and econ

  3. Effective field theory investigations of the XYZ puzzle

    NASA Astrophysics Data System (ADS)

    Segovia, Jorge

    2016-08-01

    Quantum Chromodynamics, the theory of strong interactions, predicts several types of bound states. Among them are conventional mesons (qq̅) and baryons (qqq), which have been the only states observed in experiments for years. However, in the last decade, many states that do not fit this picture have been observed at B-factories (BaBar, Belle and CLEO), at τ-charm facilities (CLEO-c, BESIII) and also at proton-proton colliders (CDF, D0, LHCb, ATLAS, CMS). There is growing evidence that at least some of the new charmonium- and bottomonium-like states, the so-called XYZ mesons, are new forms of matter such as quark-gluon hybrids, mesonic molecules or different arrangements of tetraquarks, pentaquarks... Effective Field Theories (EFTs) have been constructed for heavy-quark-antiquark bound states, but a general study of the XYZ mesons within the same framework has not yet been done. The scope of this conference proceedings is to discuss the possibilities we have in developing novel EFTs that, characterizing the conventional quarkonium states, facilitate also the systematic and model-independent description of the new exotic matter, in particular, the hybrid mesons.

  4. Investigating the Density of Isolated Field Elliptical Galaxies

    NASA Astrophysics Data System (ADS)

    Ulgen, E. Kaan

    2016-02-01

    In this thesis, 215.590 elliptical galaxies with M(r) ≤ -21 in the CFHTLS-W1 field which is covering 72 sq. deg on the sky are examined . Criterion given by Smith et al. (2004) has been used to determine isolated elliptical galaxies. 118 isolated elliptical galaxies have been determined in total. By using g, r and i photometric bands, the true-colour images of candidates are produced and visually inspected. In order to have a clean list of IfEs some candidates are excluded from the final sample after visual inspection. The final sample consists of 60 IfEs which corresponds to the 0.027 per cent of the whole sample. In other words, IfE density in the W1 is 0.8 IfE / sq.deg. Since the formation of the ellipticals in the isolated regions is not known clearly, it is crucial to determine IfEs and compare their photometric and morphological properties to the normal or cluster ellipticals. When the (g-i) distributions of three different elliptical galaxy class are compared, it is found that they have almost the same colours. When the redshift distributions of the galaxies are considered, it can be seen that IfEs formed later than the cluster and normal ellipticals. The average redshift of IfEs is determined as zphot=0.284, while for normal and cluster ellipticals, it is, respectively, 0.410 and 0.732. In addition, when the effective radii of the three elliptical systems are considered, it is found that the IfEs are bigger than the other two elliptical classes.

  5. Field and laboratory investigations of variably saturated, potential landslides

    NASA Astrophysics Data System (ADS)

    Morse, Michael S.

    Rainfall-induced landslides and debris-flows are calamitous natural hazards that are difficult to predict. Point measurement surveys of subsurface hydro-mechanical properties are often used alongside slope stability assessments to predict landslide occurrence. However, such surveys can be tedious and costly in the field scale, and invasive in the laboratory scale. Presented here are newly applied remote sensing techniques intended to improve slope stability characterization methods at a variety of scales. Electrical resistivity tomography (ERT) was used to quickly estimate soil thickness over a steep (33--40°) zero-order basin in the Oregon Coast Range. After characterizing the hydroelectrical properties at the study site, Depth-to-bedrock was interpreted from the geophysical dataset with a root mean squared error of 27 cm compared to point measurements. In the laboratory scale, a particle image velocimetry (PIV) tool was used to observe shear plane development and strain localization in a tabletop vertical cut slope simulator prior to slope failure. A vertical sliding trap door was gradually removed until the slope failed abruptly, and digital images were taken concurrently for the PIV analyses. Areas of maximum strain localization were found to coincide with the location of the eventual failure plane, showing the PIV technique can be used to detect developing shear planes in the soil. Furthermore, Culmann's Method, a commonly used two-dimensional critical height analysis, was extended to three dimensions and for use in unsaturated soils. Experimental failure heights agreed with the extended theory (within 14.3% relative error) for a range of soil moisture content and cut slope widths, compared to an 88.5% error without the three-dimensional correction. Using the extended theory, a theoretical threshold was also proposed and tested for sidewall width influence on laboratory cut slope failures.

  6. Field and Laboratory Investigations of Coastal Dune Morphodynamics

    NASA Astrophysics Data System (ADS)

    Ruggiero, P.; Maddux, T.; Kaminsky, G.; Palmsten, M.; Holman, R.; Cox, D.

    2007-12-01

    Coastal dunes are important features along many coastlines, owing to their role in sediment budgets, their use as ecologically unique habitat, and their ability to protect onshore resources from wave attack. Skillful predictions of the erosion and overtopping rates of these features are needed to quantify coastal vulnerability during major storm events. Knowledge of post-storm recovery and subsequent dune growth rates is critical to developing quantitative sediment budgets and ultimately for predicting future shoreline positions. We have been conducting both long-term field and large-scale laboratory studies to improve our understanding of dune morphodynamics and will present results of dune behavior, including various feedback mechanisms, at scales ranging from individual storm events to decadal trends. A large-scale physical model study of dune erosion was recently performed at Oregon State University's O.H. Hinsdale Wave Research Laboratory producing a comprehensive, near prototype-scale data set of hydrodynamics, sediment transport, and morphological evolution during extreme dune erosion events. The laboratory moveable bed beach/dune system was brought to equilibrium with pre-storm random wave conditions. It was subsequently subjected to attack from steadily increasing water levels and offshore wave heights simulating a natural storm surge hydrograph. Observations made include inner surf zone and swash free surface and velocities as well as wave-by-wave estimates of topographical change at high spatial resolution through the use of stereo video imagery. Initial results suggest strong feedbacks between the evolution of the foreshore profile during the storm and episodic dune slumping events. Beach topographic data have been collected quarterly along southwest Washington and northwest Oregon since 1997 resolving the seasonal to interannual morphological variability of a nearly 160-km long high-energy dissipative coastline. Major climate events (such as El Ninos

  7. Development of Point Doppler Velocimetry for Flow Field Investigations

    NASA Technical Reports Server (NTRS)

    Cavone, Angelo A.; Meyers, James F.; Lee, Joseph W.

    2006-01-01

    A Point Doppler Velocimeter (pDv) has been developed using a vapor-limited iodine cell as the sensing medium. The iodine cell is utilized to directly measure the Doppler shift frequency of laser light scattered from submicron particles suspended within a fluid flow. The measured Doppler shift can then be used to compute the velocity of the particles, and hence the fluid. Since this approach does not require resolution of scattered light from individual particles, the potential exists to obtain temporally continuous signals that could be uniformly sampled in the manner as a hot wire anemometer. This leads to the possibility of obtaining flow turbulence power spectra without the limitations of fringe-type laser velocimetry. The development program consisted of a methodical investigation of the technology coupled with the solution of practical engineering problems to produce a usable measurement system. The paper outlines this development along with the evaluation of the resulting system as compared to primary standards and other measurement technologies.

  8. A Comparative Model of Field Investigations: Aligning School Science Inquiry with the Practices of Contemporary Science

    ERIC Educational Resources Information Center

    Windschitl, Mark; Dvornich, Karen; Ryken, Amy E.; Tudor, Margaret; Koehler, Gary

    2007-01-01

    Field investigations are not characterized by randomized and manipulated control group experiments; however, most school science and high-stakes tests recognize only this paradigm of investigation. Scientists in astronomy, genetics, field biology, oceanography, geology, and meteorology routinely select naturally occurring events and conditions and…

  9. Social competence at 2 years following child traumatic brain injury.

    PubMed

    Anderson, Vicki; Beauchamp, Miriam Helen; Yeates, Keith Owen; Crossley, Louise; Ryan, Nicholas Peter; Hearps, Stephen J C; Catroppa, Cathy

    2017-02-08

    Children with traumatic brain injury (TBI) are at risk of social impairment, but research is yet to document the trajectory of these skills post-injury and factors that may predict social problems. The study addressed these gaps in knowledge, reporting on findings from a prospective, longitudinal follow-up study which investigated social outcomes post injury and explored factors contributing to these outcomes at 2 years post-injury. The sample included 113 children, 74 with TBI and 39 typically developing (TD) controls. TBI participants were recruited on presentation to hospital. Parents rated pre-injury function at that time and all children underwent magnetic resonance imaging (MRI) scan. Participants were followed up at 2 years post-injury. Outcomes were social adjustment, social participation, social relationships, and social cognition. Predictors of social outcomes examined included brain lesion characteristics, child cognition (6 months post-TBI) and behavior and environmental factors (pre-injury and 2 years). Reduced social adjustment (p=.011) and social participation (p<.001) were evident in children with TBI compared to TD controls. Poor social adjustment was predicted by externalizing behaviour problems and younger age at injury. Reduced social participation was linked to internalizing behavior problems. Greater lesion volume, lower socioeconomic status and family burden contributed to poorer social relationships, while age at injury predicted social cognition. Within the TBI group, 23% of children exhibited social impairment: younger age at injury, greater pre-injury and current behavior problems and family dysfunction, poorer IQ, processing speed, and empathy were linked to impairment. Further follow-up is required to track social recovery and the influences of cognition, brain, and environment over time.

  10. Remedial investigation sampling and analysis plan for J-Field, Aberdeen Proving Ground, Maryland. Volume 1: Field Sampling Plan

    SciTech Connect

    Benioff, P.; Biang, R.; Dolak, D.; Dunn, C.; Martino, L.; Patton, T.; Wang, Y.; Yuen, C.

    1995-03-01

    The Environmental Management Division (EMD) of Aberdeen Proving Ground (APG), Maryland, is conducting a remedial investigation and feasibility study (RI/FS) of the J-Field area at APG pursuant to the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), as amended. J-Field is within the Edgewood Area of APG in Harford County, Maryland (Figure 1. 1). Since World War II activities in the Edgewood Area have included the development, manufacture, testing, and destruction of chemical agents and munitions. These materials were destroyed at J-Field by open burning and open detonation (OB/OD). Considerable archival information about J-Field exists as a result of efforts by APG staff to characterize the hazards associated with the site. Contamination of J-Field was first detected during an environmental survey of the Edgewood Area conducted in 1977 and 1978 by the US Army Toxic and Hazardous Materials Agency (USATHAMA) (predecessor to the US Army Environmental Center [AEC]). As part of a subsequent USATHAMA -environmental survey, 11 wells were installed and sampled at J-Field. Contamination at J-Field was also detected during a munitions disposal survey conducted by Princeton Aqua Science in 1983. The Princeton Aqua Science investigation involved the installation and sampling of nine wells and the collection and analysis of surficial and deep composite soil samples. In 1986, a Resource Conservation and Recovery Act (RCRA) permit (MD3-21-002-1355) requiring a basewide RCRA Facility Assessment (RFA) and a hydrogeologic assessment of J-Field was issued by the US Environmental Protection Agency (EPA). In 1987, the US Geological Survey (USGS) began a two-phased hydrogeologic assessment in data were collected to model, groundwater flow at J-Field. Soil gas investigations were conducted, several well clusters were installed, a groundwater flow model was developed, and groundwater and surface water monitoring programs were established that continue today.

  11. Feeding Your 1- to 2-Year-Old

    MedlinePlus

    ... to 2-Year-Old Feeding Your 1- to 2-Year-Old KidsHealth > For Parents > Feeding Your 1- to 2-Year-Old Print A A A What's in ... español Alimentar a su hijo de 1 a 2 años de edad Toddlers this age are moving ...

  12. Growth and Your 1- to 2-Year-Old

    MedlinePlus

    ... 2-Year-Old Growth and Your 1- to 2-Year-Old KidsHealth > For Parents > Growth and Your 1- to 2-Year-Old Print A A A You're ... down. Your toddler may gain about 5 pounds (2.27 kg) and grow about 4 or 5 ...

  13. GRACE gravity field modeling with an investigation on correlation between nuisance parameters and gravity field coefficients

    NASA Astrophysics Data System (ADS)

    Zhao, Qile; Guo, Jing; Hu, Zhigang; Shi, Chuang; Liu, Jingnan; Cai, Hua; Liu, Xianglin

    2011-05-01

    The GRACE (Gravity Recovery And Climate Experiment) monthly gravity models have been independently produced and published by several research institutions, such as Center for Space Research (CSR), GeoForschungsZentrum (GFZ), Jet Propulsion Laboratory (JPL), Centre National d’Etudes Spatiales (CNES) and Delft Institute of Earth Observation and Space Systems (DEOS). According to their processing standards, above institutions use the traditional variational approach except that the DEOS exploits the acceleration approach. The background force models employed are rather similar. The produced gravity field models generally agree with one another in the spatial pattern. However, there are some discrepancies in the gravity signal amplitude between solutions produced by different institutions. In particular, 10%-30% signal amplitude differences in some river basins can be observed. In this paper, we implemented a variant of the traditional variational approach and computed two sets of monthly gravity field solutions using the data from January 2005 to December 2006. The input data are K-band range-rates (KBRR) and kinematic orbits of GRACE satellites. The main difference in the production of our two types of models is how to deal with nuisance parameters. This type of parameters is necessary to absorb low-frequency errors in the data, which are mainly the aliasing and instrument errors. One way is to remove the nuisance parameters before estimating the geopotential coefficients, called NPARB approach in the paper. The other way is to estimate the nuisance parameters and geopotential coefficients simultaneously, called NPESS approach. These two types of solutions mainly differ in geopotential coefficients from degree 2 to 5. This can be explained by the fact that the nuisance parameters and the gravity field coefficients are highly correlated, particularly at low degrees. We compare these solutions with the official and published ones by means of spectral analysis. It is

  14. Experimental investigations of the interaction between the ELF Earth electromagnetic fields and astrophysical processes

    NASA Astrophysics Data System (ADS)

    Grunskaya, L. V.; Efimov, V. A.; Isakevich, V. V.; Zakirov, A. A.

    2010-01-01

    Investigations of the moon and solar tides, and their interaction with the electric field of the atmospheric boundary layer are possible both by means of using big data files and by using a method of spaced reception.

  15. RAPID ARSENITE OXIDATION BY THERMUS AQUATICUS AND THERMUS THERMOPHILUS: FIELD AND LABORATORY INVESTIGATIONS. (R826189)

    EPA Science Inventory

    Thermus aquaticus and Thermus thermophilus, common inhabitants of terrestrial hot springs and thermally polluted domestic and industrial waters, have been found to rapidly oxidize arsenite to arsenate. Field investigations at a hot spring in Yellowstone National Park revealed ...

  16. An inexpensive, versatile mosquito rearing chamber for field, laboratory, and classroom investigations.

    PubMed

    Dees, William H; Figueroa, Aaron P; Schultz, George W

    2011-03-01

    An inexpensive mosquito rearing chamber for field, laboratory, and classroom investigations is described. The rearing chamber is made from plastics recycled from peanut butter jars and room deodorizers. The top of the chamber requires mesh material and gluing. The cost for the rearing chamber is negligible. The design of the chamber allows for direct field collecting of larvae and for easy knock down/cold storage of emerged adults. In addition to its use in field and laboratory investigations, the chamber is an excellent device for classroom study of insect metamorphosis.

  17. Investigation of the effects of magnetic field exposure on human melatonin. Interim report

    SciTech Connect

    Graham, C.; Cook, M.R.; Cohen, H.D.

    1994-08-01

    Several rodent studies have suggested that magnetic field exposure may alter the daily pattern of melatonin secretion. This study investigated melatonin levels in mean exposed overnight to magnetic fields of 10 mG and 200 mG. The study also assessed the potential effects of exposure on a number of performance and self-reported endpoints in the subjects. Investigation of this area is important, as altered diurnal melatonin cycles have been linked to a variety of endpoints, including reproductive outcome, neurobehavioral function, and carcinogenesis. The results of this investigation did not support the a priori hypothesis that exposure to 60-Hz magnetic fields of 10 mG and 200 mG alters nighttime melatonin levels in a population of adult males. However, the data suggested the possibility of differential sensitivity to magnetic fields based on an individual`s baseline melatonin level.

  18. [Environmental investigation of ground water contamination at Wright-Patterson Air Force Base, Ohio]. Volume 5, Field Investigation report

    SciTech Connect

    Not Available

    1992-03-01

    An environmental investigation of ground water conditions has been undertaken at Wright-Patterson Air Force Base (WPAFB), Ohio to obtain data to assist in the evaluation of a potential removal action to prevent, to the extent practicable, migration of the contaminated ground water across Base boundaries. Field investigations were limited to the central section of the southwestern boundary of Area C and the Springfield Pike boundary of Area B. Further, the study was limited to a maximum depth of 150 feet below grade. Three primary activities of the field investigation were: (1) installation of 22 monitoring wells, (2) collection and analysis of ground water from 71 locations, (3) measurement of ground water elevations at 69 locations. Volatile organic compounds including trichloroethylene, perchloroethylene, and/or vinyl chloride were detected in concentrations exceeding Maximum Contaminant Levels (MCL) at three locations within the Area C investigation area. Ground water at the Springfield Pike boundary of Area B occurs in two primary units, separated by a thicker-than-expected clay layers. One well within Area B was determined to exceed the MCL for trichloroethylene.

  19. Investigation of electric field distribution on FAC-IR-300 ionization chamber

    NASA Astrophysics Data System (ADS)

    Mohammadi, S. M.; Tavakoli-Anbaran, H.; Zeinali, H. Z.

    2016-07-01

    One of the important parameters for establishing charge particle equilibrium (CPE) conditions of free-air ionization chamber is an electric field distribution. In this paper, electric field distribution inside the ionization chamber was investigated by finite element method. For this purpose, the effects of adding guard plate and guard strips on the electric field distribution in the ionization chamber were studied. it is necessary to apply a lead box around the ionization chamber body to avoid of scattered radiation effects on the ionization chamber operation, but the lead box changes the electric field distribution. In the following, the effect of lead box on the electric field distribution was studied. Finally, electric field distribution factor (kfield) was calculated by the simulation. The results of the simulation showed that presence of the guard plate and guard strips, and applying a suitable potential to lead box, a convergence of kfield to 1 was achieved.

  20. Investigation of aberration characteristics of eyes at a peripheral visual field by individual eye model.

    PubMed

    Lou, Qiqi; Wang, Yan; Wang, Zhaoqi; Liu, Yongji; Zhang, Lin; Zhai, Yi; Fang, Hui

    2015-07-01

    We propose a method of constructing an individual eye model with a large visual field, and then investigate aberration characteristics of eyes in peripheral fields with constructed models. Twelve eyes of different aberrations are selected from 89 myopic eyes. It is shown that astigmatism increases as visual field in a quadratic manner. The variation tendency of defocus can be expressed by the cubic curve for 50% of eyes. For most of the eyes, the variation of spherical aberration shows a quadratic rule within ±24° visual field. Coma exhibits obvious individual differences. The impact of high-order aberrations on vision is mainly at a smaller visual field, and it becomes negligible beyond 24° visual field.

  1. Technology transfer opportunities: new development: computerized field manual provides valuable resource for hydrologic investigations

    USGS Publications Warehouse

    Chapel, Paul

    1996-01-01

    The U.S. Geological Survey (USGS) is known throughout the world for conducting quality scientific investigation is hydrologic environments. Proper and consistent field techniques have been an integral part of this good research. Over the past few decades, the USGS has developed and published detailed, standard protocols for conducting studies in most aspects of the hydrologic environment. These protocols have been published in a number of diverse documents. The wealth of information contained in these diverse documents can benefit other scientists in industry, government, and academia that are involved in conducting hydrologic studies. Scientists at the USGS have brought together many of the most important of the field protocols in a user-friendly, graphical-interfaced field manual that will be useful in both the field and in the office. This electronic field manual can assist hydrologists and other scientists in conducting and documenting their field activities in a manner that is recognized standard throughout the hydrologic community.

  2. Numerical Investigation of Near-Field Plasma Flows in Magnetic Nozzles

    NASA Technical Reports Server (NTRS)

    Sankaran, Kamesh; Polzin, Kurt A.

    2009-01-01

    The development and application of a multidimensional numerical simulation code for investigating near-field plasma processes in magnetic nozzles are presented. The code calculates the time-dependent evolution of all three spatial components of both the magnetic field and velocity in a plasma flow, and includes physical models of relevant transport phenomena. It has been applied to an investigation of the behavior of plasma flows found in high-power thrusters, employing a realistic magnetic nozzle configuration. Simulation of a channel-flow case where the flow was super-Alfvenic has demonstrated that such a flow produces adequate back-emf to significantly alter the shape of the total magnetic field, preventing the flow from curving back to the magnetic field coil in the near-field region. Results from this simulation can be insightful in predicting far-field behavior and can be used as a set of self-consistent boundary conditions for far-field simulations. Future investigations will focus on cases where the inlet flow is sub-Alfvenic and where the flow is allowed to freely expand in the radial direction once it is downstream of the coil.

  3. Medical Care and Your 1- to 2-Year-Old

    MedlinePlus

    ... Year-Old Medical Care and Your 1- to 2-Year-Old KidsHealth > For Parents > Medical Care and Your 1- to 2-Year-Old A A A The toddler months ... Following simple instructions? Saying a few words? Combining two words by age 2? The doctor may ask ...

  4. Field Investigation to Determine the Extent of Sediment Recontamination at the United Heckathorn Superfund Site, Richmond, California

    SciTech Connect

    Kohn, Nancy P.; Gilmore, Tyler J.

    2001-11-16

    This field investigation was undertaken to determine the present condition of sediment in Lauritzen Channel and Parr Canal approximately 2 years after completion of sediment remedial actions at the United Heckathorn Superfund site. The study was designed to supplement the post-remediation monitoring program by determining the extent and identifying potential sources of observed pesticide contamination in marine sediments near the site. Core samples collected from Lauritzen Channel and Parr Canal in July 1999 were described geologically, and samples were prepared from different sediment types, such as younger bay mud or older bay mud. Sediment samples were analyzed for grain size, organic carbon, and DDT compounds. Only minor changes have occurred in Parr Canal since remedial actions were taken in 1996-1997, but in Lauritzen Channel, DDT concentrations exceed the remedial goal of 590 ug/kg dry weight in nearly all the unconsolidated sediment (younger bay mud, sand, and disturbed older bay mud). The source of contaminated sediment could not be confirmed by this study; there was no clear correlation between high DDT concentrations and sediment remaining between the pilings, as was originally suspected. There also was no correlation between high DDT concentrations in sediment and the locations of outfalls, although some of the contamination retained by the creosote-treated wood appeared to be highest close to the known outfalls.

  5. Experimental Investigation of Effectiveness of Magnetic Field on Food Freezing Process

    NASA Astrophysics Data System (ADS)

    Suzuki, Toru; Takeuchi, Yuri; Masuda, Kazunori; Watanabe, Manabu; Shirakashi, Ryo; Fukuda, Yutaka; Tsuruta, Takaharu; Yamamoto, Kazutaka; Koga, Nobumitsu; Hiruma, Naoya; Ichioka, Jun; Takai, Kiyoshi

    Recently, several food refrigeration equipments that utilize magnetic field have attracted much attention from food production companies, consumers and mass media. However, the effectiveness of the freezers is not scientifically examined. Therefore, the effectiveness should be clarified by experiments or theoretical considerations. In this study, the effect of weak magnetic field (about 0.0005 T) on freezing process of several kinds of foods was investigated by using a specially designed freezer facilitated with magnetic field generator. The investigation included the comparison of freezing curves, drip amount, physicochemical evaluations on color and texture, observation of microstructure, and sensory evaluation. From the results of the control experiments, it can be concluded that weak magnetic field around 0.0005 T provided no significant difference on temperature history during freezing and on the qualities of frozen foods, within our experimental conditions.

  6. Remedial investigation report for J-Field, Aberdeen Proving Ground, Maryland. Volume 3: Ecological risk assessment

    SciTech Connect

    Hlohowskyj, I.; Hayse, J.; Kuperman, R.; Van Lonkhuyzen, R.

    2000-02-25

    The Environmental Management Division of the U.S. Army Aberdeen Proving Ground (APG), Maryland, is conducting a remedial investigation (RI) and feasibility study (FS) of the J-Field area at APG, pursuant to the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), as amended. As part of that activity, Argonne National Laboratory (ANL) conducted an ecological risk assessment (ERA) of the J-Field site. This report presents the results of that assessment.

  7. Investigation of Spatial Distribution of Radiocesium in a Paddy Field as a Potential Sink

    PubMed Central

    Tanaka, Kazuya; Iwatani, Hokuto; Takahashi, Yoshio; Sakaguchi, Aya; Yoshimura, Kazuya; Onda, Yuichi

    2013-01-01

    Surface soils, under various land uses, were contaminated by radionuclides that were released by the Fukushima Daiichi Nuclear Power Plant accident. Because paddy fields are one of the main land uses in Japan, we investigated the spatial distribution of radiocesium and the influence of irrigation water in a paddy field during cultivation. Soil core samples collected at a paddy field in Fukushima showed that plowing had disturbed the original depth distribution of radiocesium. The horizontal distribution of radiocesium did not show any evidence for significant influence of radiocesium from irrigation water, and its accumulation within the paddy field, since the original amount of radiocesium was much larger than was added into the paddy field by irrigation water. However, it is possible that rainfall significantly increases the loading of radiocesium. PMID:24260481

  8. Investigation on magnetic field dependent modulus of epoxidized natural rubber based magnetorheological elastomer

    NASA Astrophysics Data System (ADS)

    Yunus, N. A.; Mazlan, S. A.; Ubaidillah; Aziz, S. A. A.; Khairi, M. H. Ahmad; Wahab, N. A. A.; Shilan, S. T.

    2016-11-01

    This paper presents an investigation on the use of epoxidized natural rubber (ENR) as a matrix of magnetorheological elastomers (MREs). Isotropic ENR-based MRE samples were synthesized by homogeneously mixed the ENR compound with carbonyl iron particles (CIPs). The microstructure of the sample was observed, and the magnetic field-dependent moduli were analyzed using rheometer. The influences of excitation frequency, CIPs content and magnetic field on the field-dependent moduli of ENR-based MREs were evaluated through dynamic shear test. The microstructure of MRE samples demonstrated the dispersed CIPs in the ENR matrix. The remarkable increment of storage and loss moduli of the ENR-based MREs has exhibited the magnetically controllable storage and loss moduli of the samples when exposed to the magnetic field. Consequently, the CIPs content, frequency and magnetic field were significantly influenced the dynamic moduli of the ENR-based MREs.

  9. Investigation of spatial distribution of radiocesium in a paddy field as a potential sink.

    PubMed

    Tanaka, Kazuya; Iwatani, Hokuto; Takahashi, Yoshio; Sakaguchi, Aya; Yoshimura, Kazuya; Onda, Yuichi

    2013-01-01

    Surface soils, under various land uses, were contaminated by radionuclides that were released by the Fukushima Daiichi Nuclear Power Plant accident. Because paddy fields are one of the main land uses in Japan, we investigated the spatial distribution of radiocesium and the influence of irrigation water in a paddy field during cultivation. Soil core samples collected at a paddy field in Fukushima showed that plowing had disturbed the original depth distribution of radiocesium. The horizontal distribution of radiocesium did not show any evidence for significant influence of radiocesium from irrigation water, and its accumulation within the paddy field, since the original amount of radiocesium was much larger than was added into the paddy field by irrigation water. However, it is possible that rainfall significantly increases the loading of radiocesium.

  10. Experimental Investigation of Pool Boiling Heat Transfer Enhancement in Microgravity in the Presence of Electric Fields

    NASA Technical Reports Server (NTRS)

    Herman, C.

    2000-01-01

    The research carried out in the Heat Transfer Laboratory of the Johns Hopkins University was motivated by previous studies indicating that in terrestrial applications nucleate boiling heat transfer can be increased by a factor of 50 when compared to values obtained for the same system without electric fields. Imposing an external electric field holds the promise to improve pool boiling heat transfer in low gravity, since a phase separation force other than gravity is introduced. The influence of electric fields on bubble formation has been investigated both experimentally and theoretically.

  11. Investigation of brain potentials in sleeping humans exposed to the electromagnetic field of mobile phones.

    PubMed

    Lebedeva, N N; Sulimov, A V; Sulimova, O P; Korotkovskaya, T I; Gailus, T

    2001-01-01

    An investigation was made of 8-hour EEG tracings of sleeping humans exposed to the electromagnetic field of a GSM-standard mobile phone. To analyze the EEG-patterns, manual scoring, nonlinear dynamics, and spectral analysis were employed. It was found that, when human beings were exposed to the electromagnetic field of a cellular phone, their cerebral cortex biopotentials revealed an increase in the alpha-range power density as compared to the placebo experiment. It was also found that the dimension of EEG correlation dynamics and the relation of sleep stages changed under the influence of the electromagnetic field of a mobile phone.

  12. Theoretical investigation of boundary contours of ground-state atoms in uniform electric fields

    NASA Astrophysics Data System (ADS)

    Shi, Hua; Zhao, Dong-Xia; Yang, Zhong-Zhi

    2015-12-01

    The boundary contours were investigated for first 54 ground-state atoms of the periodic table when they are in uniform electric fields of strengths 106, 107 and 108 V/m. The atomic characteristic boundary model in combination with an ab-initio method was employed. Some regularities of the deformation of atoms, ΔR, in above electric fields are revealed. Furthermore, atomic polarisabilities of the first 54 elements of the periodic table are shown to correlate strongly with the mean variation rate of atomic radial size divided by the strength of the electric field F, ?, which provides a predictive method of calculating atomic polarisabilities of 54 atoms.

  13. Investigation of different magnetic field configurations using an electrical, modular Zeeman slower

    SciTech Connect

    Ohayon, Ben; Ron, Guy

    2015-10-15

    We present a method of constructing an automatically reconfigurable, modular, electronic Zeeman slower, which is remotely controlled. This setup is used to investigate the ability of different magnetic field profiles to slow thermal atoms to the capture velocity of a magneto-optical-trap. We show that a simple numerical optimization process yields better results than the commonly used approach for deciding on the appropriate field and comes close to the optimum field, found by utilizing a fast feedback loop which uses a genetic algorithm. Our new numerical method is easily adaptable to a variety of existing slower designs and may be beneficial where feedback is unavailable.

  14. MO-G-BRF-09: Investigating Magnetic Field Dose Effects in Mice: A Monte Carlo Study

    SciTech Connect

    Rubinstein, A; Guindani, M; Followill, D; Melancon, A; Hazle, J; Court, L

    2014-06-15

    Purpose: In MRI-linac treatments, radiation dose distributions are affected by magnetic fields, especially at high-density/low-density interfaces. Radiobiological consequences of magnetic field dose effects are presently unknown; therefore, preclinical studies are needed to ensure the safe clinical use of MRI-linacs. This study investigates the optimal combination of beam energy and magnetic field strength needed for preclinical murine studies. Methods: The Monte Carlo code MCNP6 was used to simulate the effects of a magnetic field when irradiating a mouse-sized lung phantom with a 1.0cmx1.0cm photon beam. Magnetic field effects were examined using various beam energies (225kVp, 662keV[Cs-137], and 1.25MeV[Co-60]) and magnetic field strengths (0.75T, 1.5T, and 3T). The resulting dose distributions were compared to Monte Carlo results for humans with various field sizes and patient geometries using a 6MV/1.5T MRI-linac. Results: In human simulations, the addition of a 1.5T magnetic field caused an average dose increase of 49% (range:36%–60%) to lung at the soft tissue-to-lung interface and an average dose decrease of 30% (range:25%–36%) at the lung-to-soft tissue interface. In mouse simulations, the magnetic fields had no effect on the 225kVp dose distribution. The dose increases for the Cs-137 beam were 12%, 33%, and 49% for 0.75T, 1.5T, and 3.0T magnetic fields, respectively while the dose decreases were 7%, 23%, and 33%. For the Co-60 beam, the dose increases were 14%, 45%, and 41%, and the dose decreases were 18%, 35%, and 35%. Conclusion: The magnetic field dose effects observed in mouse phantoms using a Co-60 beam with 1.5T or 3T fields and a Cs-137 beam with a 3T field compare well with those seen in simulated human treatments with an MRI-linac. These irradiator/magnet combinations are suitable for preclinical studies investigating potential biological effects of delivering radiation therapy in the presence of a magnetic field. Partially funded by Elekta.

  15. An X-ray Investigation of the NGC 346 Field in the SMC (2): The Field Population

    NASA Technical Reports Server (NTRS)

    Naze, Y.; Hartwell, J. M.; Stevens, I. R.; Manfroid, J.; Marchenko. S.; Corcoran, M. F.; Moffat, A. F. J.; Skalkowski, G.; White, Nicholas E. (Technical Monitor)

    2002-01-01

    We present results from a Chandra observation of the NGC 346 cluster, the ionizing source of N66, the most luminous H II region and the largest star formation region in the SMC. In the first part of this investigation, we have analysed the X-ray properties of the cluster itself and the remarkable star HD 5980. But the field contains additional objects of interest. In total, 79 X-ray point sources were detected in the Chandra observation and we investigate here their characteristics in details. The sources possess rather high HRs, and their cumulative luminosity function is steeper than the SMC's trend. Their absorption columns suggest that most of the sources belong to NGC 346. Using new UBVRI imaging with the ESO 2.2m telescope, we also discovered possible counterparts for 36 of these X-ray sources. Finally, some objects show X-ray and/or optical variability, and thus need further monitoring.

  16. Field Investigations of Lactate-Stimulated Bioreduction of Cr(VI) at Hanford 100H

    SciTech Connect

    T. C. Hazen; B. Faybishenko; D. Joyner; S. Borglin; E. Brodie; S. Hubbard; K. Williams; J. Peterson; J. Wan; T. Tokunaga; M. Firestone; P. E. Long; Resch, C.T.; Newcomer, D.; Koenigsberg, S.; Willet, A. C. T. Resch, and D. Newcomer , S. Koenigsberg and A. Willet Field Investigations of Lactate-Stimulated Bioreduction of Cr at Hanford 100H

    2005-04-20

    The overall objective of this paper is to carry out field investigations to assess the potential for immobilizing and detoxifying chromium-contaminated groundwater using lactate-stimulated bioreduction of Cr(VI) to Cr(III) at the Hanford 100H site.

  17. Distinguishing among Declarative, Descriptive and Causal Questions to Guide Field Investigations and Student Assessment

    ERIC Educational Resources Information Center

    Odom, Arthur Louis; Bell, Clare V.

    2011-01-01

    Teachers as well as students often have difficulty formulating good research questions because not all questions lend themselves to scientific investigation. The following is a guide for high-school and college life-science teachers to help students define question types central to biological field studies. The mayfly nymph was selected as the…

  18. 75 FR 77958 - Gravesite Reservation Survey (2 Year); Correction

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-14

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF VETERANS AFFAIRS Gravesite Reservation Survey (2 Year); Correction AGENCY: National Cemetery Administration, Department of Veterans Affairs. ACTION: Notice; correction. SUMMARY: The Department of Veterans Affairs...

  19. Investigation of flow and solute transport at the field scale through heterogeneous deformable porous media

    NASA Astrophysics Data System (ADS)

    Chang, Ching-Min; Yeh, Hund-Der

    2016-09-01

    This work describes an investigation of the spatial statistical structure of specific discharge field and solute transport process of a nonreactive solute at the field scale through a heterogeneous deformable porous medium. The flow field is driven by a vertical gradient in the excess pore water pressure induced by a step increase in load applied on the upper part of a finite-thickness aquifer. The non-stationary spectral representation is adopted to characterize the spatial covariance of the specific discharge field necessary for the development of the solute particle trajectory statistics using the Lagrangian formalism. We show that the statistics of the specific discharge and particle trajectory derived herein are non-stationary and functions of the coefficient of soil compressibility, μ. The effect of μ on the relative variation of specific discharge and the solute particle trajectory statistics are analyzed upon evaluating our expressions.

  20. An X-ray Investigation of the NGC 346 Field in the SMC (2): The Field Population

    NASA Technical Reports Server (NTRS)

    Naze, Y.; Hartwell, J. M.; Stevens, I. R.; Manfroid, J.; Marchenko, S.; Corcoran, M. F.; Moffat, A. F. J.; Skalkowski, G.

    2003-01-01

    We present results from a Chandra observation of the NGC 346 cluster, which is the ionizing source of N66, the most luminous HII region and the largest star formation region in the SMC. In the first part of this investigation, we have analysed the X-ray properties of the cluster itself and the remarkable star HD 5980. But the field contains additional objects of interest. In total, 79 X-ray point sources were detected in the Chandra observation: this is more than five times the number of sources detected by previous X-ray surveys. We investigate here their characteristics in detail. The sources possess rather high hardness ratios, and their cumulative luminosity function is steeper than that for the rest of the SMC at higher .luminosities. Their absorption columns suggest that most of the sources belong to NGC346. Using new UBV RI imaging with the ESO 2.2m telescope, we also discovered possible counterparts for 36 of these X-ray sources and estimated a B spectral type for a large number of these counterparts. This tends to suggest that most of the X-ray sources in the field are in fact X-ray binaries. Finally, some objects show X-ray and/or optical variability, with a need for further monitoring.

  1. Investigation of pulsed electromagnetic field as a novel organic pre-sowing method on germination and initial growth stages of cotton.

    PubMed

    Bilalis, Dimitrios J; Katsenios, Nikolaos; Efthimiadou, Aspasia; Karkanis, Anestis; Efthimiadis, Panagiotis

    2012-06-01

    Two different pre-sowing techniques have been investigated for their influence in an important industrial plant, namely cotton. Priming methods are very useful for agricultural practices because they improve crop seedling establishment, especially when environmental conditions are not optimum. Pulsed electromagnetic fields have been found to promote germination and improve early growth characteristics of cotton seedlings. Such priming techniques are especially valuable in organic cultivation, where chemical compounds are prohibited. PEG treatment showed an enhancement in some measurements, however in some cases the results were not statistically different compared to control plants. In addition, PEG treatment is a sophisticated method that is far from agricultural practices and farmers. In this research, two different ages of seeds were used (1- and 2-year-old) in order to investigate the promotory effects of priming techniques. Magnetic field treatment of 15 min was found to stimulate germination percentage and to promote seeds, resulting in 85% higher values than control seeds under real field conditions. Furthermore, seeds that were treated with magnetic field performed better in terms of early-stage measurements and root characteristics.

  2. Action of combined magnetic fields on aqueous solution of glutamic acid: the further development of investigations.

    PubMed

    Giuliani, Livio; Grimaldi, Settimio; Lisi, Antonella; D'Emilia, Enrico; Bobkova, Natalia; Zhadin, Mikhail

    2008-01-25

    In the present work the results of the known investigation of the influence of combined static (40 microT) and alternating (amplitude of 40 nT) parallel magnetic fields on the current through the aqueous solution of glutamic acid, were successfully replicated. Fourteen experiments were carried out by the application of the combined magnetic fields to the solution placed into a Plexiglas reaction vessel at application of static voltage to golden electrodes placed into the solution. Six experiments were carried out by the application of the combined magnetic fields to the solution placed in a Plexiglas reaction vessel, without electrodes, within an electric field, generated by means of a capacitor at the voltage of 27 mV. The frequency of the alternating field was scanned within the bounds of 1.0 Hz including the cyclotron frequency corresponding to a glutamic acid ion and to the applied static magnetic field. In this study the prominent peaks with half-width of approximately 0.5 Hz and with different heights (till 80 nA) were registered at the alternating magnetic field frequency equal to the cyclotron frequency (4.2 Hz). The general reproducibility of the investigated effects was 70% among the all solutions studied by us and they arose usually after 40-60 min. after preparation of the solution. In some made-up solutions the appearance of instability in the registered current was noted in 30-45 min after the solution preparation. This instability endured for 20-40 min. At the end of such instability period the effects of combined fields action appeared practically every time. The possible mechanisms of revealed effects were discussed on the basis of modern quantum electrodynamics.

  3. An investigation into the induced electric fields from transcranial magnetic stimulation

    NASA Astrophysics Data System (ADS)

    Hadimani, Ravi; Lee, Erik; Duffy, Walter; Waris, Mohammed; Siddiqui, Waquar; Islam, Faisal; Rajamani, Mahesh; Nathan, Ryan; Jiles, David; David C Jiles Team; Walter Duffy Collaboration

    Transcranial magnetic stimulation (TMS) is a promising tool for noninvasive brain stimulation that has been approved by the FDA for the treatment of major depressive disorder. To stimulate the brain, TMS uses large, transient pulses of magnetic field to induce an electric field in the head. This transient magnetic field is large enough to cause the depolarization of cortical neurons and initiate a synaptic signal transmission. For this study, 50 unique head models were created from MRI images. Previous simulation studies have primarily used a single head model, and thus give a limited image of the induced electric field from TMS. This study uses finite element analysis simulations on 50 unique, heterogeneous head models to better investigate the relationship between TMS and the electric field induced in brain tissues. Results showed a significant variation in the strength of the induced electric field in the brain, which can be reasonably predicted by the distance from the TMS coil to the stimulated brain. Further, it was seen that some models had high electric field intensities in over five times as much brain volume as other models.

  4. Field investigation source area ST58 old Quartermaster service station, Eielson Air Force Base, Alaska

    SciTech Connect

    Liikala, T.L.; Evans, J.C.

    1995-01-01

    Source area ST58 is the site of the old Quartermaster service station at Eielson Air Force Base, Alaska. The source area is one of several Source Evaluation Report sites being investigated by Pacific Northwest Laboratory for the US Air Force as candidates for no further remedial action, interim removal action, or a remedial investigation/feasibility study under a Federal Facilities Agreement. The purpose of this work was to characterize source area ST58 and excavate the most contaminated soils for use in composting treatability studies. A field investigation was conducted to determine the nature and extent of soil contamination. The field investigation entailed a records search; grid node location, surface geophysical, and soil gas surveys; and test pit soil sampling. Soil excavation followed based on the results of the field investigation. The site was backfilled with clean soil. Results from this work indicate close spatial correlation between screening instruments, used during the field investigation and soil excavation, and laboratory analyses. Gasoline was identified as the main subsurface contaminant based on the soil gas surveys and test pit soil sampling. A center of contamination was located near the northcentral portion of the source area, and a center was located in the northwestern comer. The contamination typically occurred near or below a former soil horizon probably as a result of surface spills and leaks from discontinuities and/or breaks in the underground piping. Piping locations were delineated during the surface geophysical surveys and corresponded very well to unscaled drawings of the site. The high subsurface concentrations of gasoline detected in the northwestern comer of the source area probably reflect ground-water contamination and/or possibly floating product.

  5. Epidemiologic Responses to Anthrax Outbreaks: A Review of Field Investigations, 1950–2001

    PubMed Central

    Bales, Michael E.; Brachman, Philip S.; Kaufmann, Arnold F.; Klatsky, Peter C.; Ashford, David A.

    2002-01-01

    We used unpublished reports, published manuscripts, and communication with investigators to identify and summarize 49 anthrax-related epidemiologic field investigations conducted by the Centers for Disease Control and Prevention from 1950 to August 2001. Of 41 investigations in which Bacillus anthracis caused human or animal disease, 24 were in agricultural settings, 11 in textile mills, and 6 in other settings. Among the other investigations, two focused on building decontamination, one was a response to bioterrorism threats, and five involved other causes. Knowledge gained in these investigations helped guide the public health response to the October 2001 intentional release of B. anthracis, especially by addressing the management of anthrax threats, prevention of occupational anthrax, use of antibiotic prophylaxis in exposed persons, use of vaccination, spread of B. anthracis spores in aerosols, clinical diagnostic and laboratory confirmation methods, techniques for environmental sampling of exposed surfaces, and methods for decontaminating buildings. PMID:12396934

  6. Investigating an alternative ring design of transducer arrays for tumor treating fields (TTFields).

    PubMed

    Macedo, Mario; Wenger, Cornelia; Salvador, Ricardo; Fernandes, Sofia R; Miranda, Pedro C

    2016-08-01

    Tumor treating fields (TTFields) is a therapy that inhibits cell proliferation and has been approved by the U.S Food and Drug Administration (FDA) for the treatment of Glioblastoma Multiforme. This anti-mitotic technique works non-invasively and regionally, and is associated with less toxicity and a better quality of life. Currently a device called Optune™ is clinically used which works with two perpendicular and alternating array pairs each consisting of 3×3 transducers. The aim of this study is to investigate a theoretical alternative array design which consists of two rings of 16 transducers and thus permits various field directions. A realistic human head model with isotropic tissues was used to simulate the electric field distribution induced by the two types of array layouts. One virtual tumour was modelled as a sphere in the white matter close to one lateral ventricle. Four alternative ring design directions were evaluated by activating arrays of 2×2 transducers on opposite sides of the head. The same amount of current was passed through active transducer arrays of the Optune system and the ring design. The electric field distribution in the brain differs for the various array configurations, with higher fields between activated transducer pairs and lower values in distant areas. Nonetheless, the average electric field strength values in the tumour are comparable for the various configurations. Values between 1.00 and 1.91 V/cm were recorded, which are above the threshold for effective treatment. Increasing the amount of field directions could possibly also increase treatment efficacy, because TTFields' effect on cancer cells is highest when the randomly distributed cell division axis is aligned with the field. The results further predict that slightly changing transducer positions only has a minor effect on the electric field. Thus patients might have some freedom to adjust array positions without major concern for treatment efficacy.

  7. Investigation of turbulence in reversed field pinch plasma by using microwave imaging reflectometry

    SciTech Connect

    Shi, Z. B.; Nagayama, Y.; Hamada, Y.; Yamaguchi, S.; Hirano, Y.; Kiyama, S.; Koguchi, H.; Sakakita, H.; Michael, C. A.; Yambe, K.

    2011-10-15

    Turbulence in the reversed field pinch (RFP) plasma has been investigated by using the microwave imaging reflectometry in the toroidal pinch experiment RX (TPE-RX). In conventional RFP plasma, the fluctuations are dominated by the intermittent blob-like structures. These structures are accompanied with the generation of magnetic field, the strong turbulence, and high nonlinear coupling among the high and low k modes. The pulsed poloidal current drive operation, which improves the plasma confinement significantly, suppresses the dynamo, the turbulence, and the blob-like structures.

  8. Investigation of mechanosensation in C. elegans using light field calcium imaging

    PubMed Central

    Shaw, Michael; Elmi, Muna; Pawar, Vijay; Srinivasan, Mandayam A.

    2016-01-01

    We describe a new experimental approach to investigate touch sensation in the model organism C. elegans using light field deconvolution microscopy. By combining fast volumetric image acquisition with controlled indentation of the organism using a high sensitivity force transducer, we are able to simultaneously measure activity in multiple touch receptor neurons expressing the calcium ion indicator GCaMP6s. By varying the applied mechanical stimulus we show how this method can be used to quantify touch sensitivity in C. elegans. We describe some of the challenges of performing light field calcium imaging in moving samples and demonstrate that they can be overcome by simple data processing. PMID:27446713

  9. Determination of satellite valley position in GaN emitter from photoexcited field emission investigations

    NASA Astrophysics Data System (ADS)

    Semenenko, M.; Yilmazoglu, O.; Hartnagel, H. L.; Pavlidis, D.

    2011-01-01

    Argon plasma etched GaN field-emitter rods with nanometer-scale diameter were fabricated on GaN grown on an n+-GaN substrate. Their electron field emission properties were investigated both without and under illumination by using light sources with various wavelengths. The Fowler-Nordheim current-voltage characteristics of the cathodes show a change in slope for illuminated cathodes. The electron affinity difference ΔE between the different valleys in the conduction band has been ascertained and is in the range from 1.18 up to 1.21 eV.

  10. An Investigation of Transonic Flow Fields Surrounding Hot and Cold Sonic Jets

    NASA Technical Reports Server (NTRS)

    Lee, George

    1961-01-01

    An investigation at free-stream Mach numbers of 0.90 t o 1.10 was made to determine (1) the jet boundaries and the flow fields around hot and cold jets, and (2) whether a cold-gas jet could adequately simulate the boundary and flow field of hot-gas jet. Schlieren photographs and static-pressure surveys were taken in the vacinity of a sonic jet which was operated over a range of jet pressure ratios of 1 to 6, specific heat ratios at the nozzle exit of 1.29 and 1.40, and jet temperatures up to 2600 R.

  11. The Alaska earthquake, March 27, 1964: field investigations and reconstruction effort

    USGS Publications Warehouse

    Hansen, Wallace R.; Eckel, Edwin B.; Schaem, William E.; Lyle, Robert E.; George, Warren; Chance, Genie

    1966-01-01

    One of the greatest geotectonic events of our time occurred in southern Alaska late in the afternoon of March 27, 1964. Beneath a leaden sky, the chill of evening was just settling over the Alaskan countryside. Light snow was falling on some communities. It was Good Friday, schools were closed, and the business day was ending. Suddenly without warning half of Alaska was rocked and jarred by the most violent earthquake to occur in North America this century. The descriptive summary that follows is based on the work of many investigators. A large and still-growing scientific literature has accumulated since the earthquake, and this literature has been freely drawn upon here. In particular, the writers have relied upon the findings of their colleagues in the Geological Survey. Some of these findings have been published, but some are still being prepared for publication. Moreover, some field investigations are still in progress. This is the first in a series of six reports that the U.S. Geological Survey published on the results of a comprehensive geologic study that began, as a reconnaissance survey, within 24 hours after the March 27, 1964, Magnitude 9.2 Great Alaska Earthquake and extended, as detailed investigations, through several field seasons. The 1964 Great Alaska earthquake was the largest earthquake in the U.S. since 1700. Professional Paper 541, in 1 part, describes Field Investigations and Reconstruction Effort.

  12. Laboratory experiments investigating magnetic field production via the Weibel instability in interpenetrating plasma flows

    NASA Astrophysics Data System (ADS)

    Huntington, Channing; Fiuza, Frederico; Ross, James Steven; Zylstra, Alex; Pollock, Brad; Drake, R. Paul; Froula, Dustin; Gregori, Gianluca; Kugland, Nathan; Kuranz, Carolyn; Levy, Matthew; Li, Chikang; Meinecke, Jena; Petrasso, Richard; Remington, Bruce; Ryutov, Dmitri; Sakawa, Youichi; Spitkovsky, Anatoly; Takabe, Hideke; Turnbull, David; Park, Hye-Sook

    2015-08-01

    Astrophysical collisionless shocks are often associated with the presence of strong magnetic fields in a plasma flow. The magnetic fields required for shock formation may either be initially present, for example in supernova remnants or young galaxies, or they may be self-generated in systems such as gamma-ray bursts (GRBs). In the case of GRB outflows, the intense magnetic fields are greater than those seeded by the GRB progenitor or produced by misaligned density and temperature gradients in the plasma flow (the Biermann-battery effect). The Weibel instability is one candidate mechanism for the generation of sufficiently strong fields to create a collisionless shock. Despite their crucial role in astrophysical systems, observation of the magnetic fields produced by Weibel instabilities in experiments has been challenging. Using a proton probe to directly image electromagnetic fields, we present evidence of Weibel-generated magnetic fields that grow in opposing, initially unmagnetized plasma flows from laser-driven laboratory experiments. Three-dimensional particle-in-cell simulations reveal that the instability efficiently extracts energy from the plasma flows, and that the self-generated magnetic energy reaches a few percent of the total energy in the system. This result demonstrates an experimental platform suitable for the investigation of a wide range of astrophysical phenomena, including collisionless shock formation in supernova remnants, large-scale magnetic field amplification, and the radiation signature from gamma-ray bursts.This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  13. Investigation of Phototriangulation Accuracy with Using of Various Techniques Laboratory and Field Calibration

    NASA Astrophysics Data System (ADS)

    Chibunichev, A. G.; Kurkov, V. M.; Smirnov, A. V.; Govorov, A. V.; Mikhalin, V. A.

    2016-10-01

    Nowadays, aerial survey technology using aerial systems based on unmanned aerial vehicles (UAVs) becomes more popular. UAVs physically can not carry professional aerocameras. Consumer digital cameras are used instead. Such cameras usually have rolling, lamellar or global shutter. Quite often manufacturers and users of such aerial systems do not use camera calibration. In this case self-calibration techniques are used. However such approach is not confirmed by extensive theoretical and practical research. In this paper we compare results of phototriangulation based on laboratory, test-field or self-calibration. For investigations we use Zaoksky test area as an experimental field provided dense network of target and natural control points. Racurs PHOTOMOD and Agisoft PhotoScan software were used in evaluation. The results of investigations, conclusions and practical recommendations are presented in this article.

  14. Investigation of ginkgo biloba leave extracts as corrosion and Oil field microorganism inhibitors

    PubMed Central

    2013-01-01

    Ginkgo biloba (Ginkgoaceae), originating from China, now distributes all over the world. Wide application of Ginkgo biloba extracts is determined by the main active substances, flavonoids and terpenoids, which indicates its extracts suitable to be used as an effective corrosion inhibitor. The extracts of Ginkgo biloba leave have been investigated on the corrosion inhibition of Q235A steel with weight loss and potentiodynamic polarisation techniques. The inhibition efficiency of the extracts varies with extract concentration. The extracts inhibit corrosion mainly by adsorption mechanism. Potentiodynamic polarisation studies show that extracts are mixed type inhibitors. The antibacterial activity of the extracts against oil field microorganism (SRB, IB and TGB) was also investigated. PMID:23651921

  15. Investigation of Electromagnetic Field Threat to Fuel Tank Wiring of a Transport Aircraft

    NASA Technical Reports Server (NTRS)

    Ely, Jay J.; Nguyen, Truong X.; Dudley, Kenneth L.; Scearce, Stephen A.; Beck, Fred B.; Deshpande, Manohar D.; Cockrell, C. R.

    2000-01-01

    National Transportation Safety Board investigators have questioned whether an electrical discharge in the Fuel Quantity Indication System (FQIS) may have initiated the TWA-800 center wing tank explosion. Because the FQIS was designed to be incapable of producing such a discharge on its own, attention has been directed to mechanisms of outside electromagnetic influence. To support the investigation, the NASA Langley Research Center was tasked to study the potential for radiated electromagnetic fields from external radio frequency (RF) transmitters and passenger carried portable electronic devices (PEDs) to excite the FQIS enough to cause arcing, sparking or excessive heating within the fuel tank.

  16. Initial Results from the Vector Electric Field Investigation on the C/NOFS Satellite

    NASA Technical Reports Server (NTRS)

    Pfaff, R.; Rowland, D.; Acuna, M.; Le, G.; Farrell, W.; Holzworth, R.; Wilson, G.; Burke, W.; Freudenreich, H.; Bromund, K.; Liebrecht, C.; Martin, S.; Kujawski, J.; Uribe, P.; Fourre, R.; McCarthy, M.; Maynard, N.; Berthelier, J.-J.; Steigies, C.

    2009-01-01

    Initial results are presented from the Vector Electric Field Investigation (VEFI) on the Air Force Communication/Navigation Outage Forecasting System (C/NOFS) satellite, a mission designed to understand, model, and forecast the presence of equatorial ionospheric irregularities. The VEFI instrument includes a vector DC electric field detector, a fixed-bias Langmuir probe operating in the ion saturation regime, a flux gate magnetometer, an optical lightning detector, and associated electronics including a burst memory. The DC electric field detector has revealed zonal and meridional electric fields that undergo a diurnal variation, typically displaying eastward and outward-directed fields during the day and westward and downward-directed fields at night. In general, the measured DC electric field amplitudes are in the 0.5-2 mV/m range, corresponding to I3 x B drifts of the order of 30-150 m/s. What is surprising is the high degree of large-scale (10's to 100's of km) structure in the DC electric field, particularly at night, regardless of whether well-defined spread-F plasma density depletions are present. The spread-F density depletions and corresponding electric fields that have been detected thus far have displayed a preponderance to appear between midnight and dawn. Associated with the narrow plasma depletions that are detected are broad spectra of electric field and plasma density irregularities for which a full vector set of measurements is available for detailed study. On some occasions, localized regions of low frequency (< 8 Hz) magnetic field broadband irregularities have been detected, suggestive of filamentary currents, although there is no one-to-one correspondence of these waves with the observed plasma density depletions, at least within the data examined thus far. Finally, the data set includes a wide range of ELF/VLF/HF waves corresponding to a variety of plasma waves, in particular banded ELF hiss, whistlers, and lower hybrid wave turbulence

  17. Shemya AFB, Alaska 1992 IRP field investigation report. Volume 1: Final report

    SciTech Connect

    Not Available

    1993-02-01

    The US Air Force is currently investigating 22 sites on Shemya Air Force Base (AFB) to determine if past spill and disposal activities have caused environmental damage. These investigations are being carried out under the Air Force`s Installation Restoration Program (IRP). As a part of the IRP program, field investigations were performed in 1992 to obtain the information needed to assess what future actions willneed to be carried out at each site. The island`s drinking water supply was also investigated. Activities completed at 10 selected sites during the 1992 field investigation included surface sampling to determine the lateral extent of contamination, subsurface sampling to determine the vertical extent of contamination, and the installation of well points and monitoring wells to determine the direction of groundwater flow and if the groundwater has been affected by a site. In addition, geophysical surveys were performed at most sites to identify site boundaries and check for the presence of buried metal to be avoided during drilling activities.

  18. Investigation of Acoustic Fields Generated by Eddy Currents Using an Atomic Force Microscope (Postprint)

    DTIC Science & Technology

    2012-08-01

    AFRL-RX-WP-JA-2014-0230 INVESTIGATION OF ACOUSTIC FIELDS GENERATED BY EDDY CURRENTS USING AN ATOMIC FORCE MICROSCOPE (POSTPRINT) V...Institute of Physics AIR FORCE RESEARCH LABORATORY MATERIALS AND MANUFACTURING DIRECTORATE WRIGHT-PATTERSON AIR FORCE BASE, OH 45433-7750 AIR... FORCE MATERIEL COMMAND UNITED STATES AIR FORCE NOTICE AND SIGNATURE PAGE Using Government drawings, specifications, or other data included in

  19. Sixth grade students' perceptions of science and scientists following a field-based science investigation

    NASA Astrophysics Data System (ADS)

    Kielborn, Terrie Leigh

    The purpose of this study was to better understand the influences of field-based investigations on sixth graders' perceptions of science and scientists. I chose to do this study due to my desire for middle grade students to have the opportunity to learn science as scientists, to increase their interest in science, and to create a positive attitude about science at the middle school level. The implications of the findings are directed toward the future of middle school science education. Thirty-five students from two sixth grade classes drew their perceptions of a scientist using the Draw-A-Scientists Test (DAST), before and after their participation in a field-based science investigation. Three students were interviewed prior to, between each, and after the field-based investigations. Using the pre-DAST and post-DAST drawings along with the conversations of the students, I found three significant differences that indicated a change in the students' perception of scientists: (1) youth; (2) outdoors; and (3) symbols of research. Prior to the study, 74% of the sixth graders viewed scientists as middle-aged or elderly as compared to 43% after the stream investigations. The stream as "the site" for the field-based investigations, influenced 57% of the students to include the outdoors in their post-DAST drawings as compared to 26% in the pre-DAST. Students drew symbols of research 43% on the pre-DAST but increased to 69% on the post-DAST. Many of the drawings and conversations from the confirm the notion that these sixth graders preferred to learn science outside and using scientific tools. These students felt that they were doing real science, and real science is what scientists do. By using field-based science investigations regularly, I believe there is the potential for putting students on the frontier of science. This goal aligns with the National Science Education Standards that call for students to have opportunities for "inquiry into authentic questions

  20. Retrospective investigation of geomagnetic field time-series during the 2009 L'Aquila seismic sequence

    NASA Astrophysics Data System (ADS)

    Masci, Fabrizio; Di Persio, Manuele

    2012-03-01

    This paper reports the analyses of ULF (Ultra-Low-Frequency) geomagnetic field observations coming from the Geomagnetic Observatory of L'Aquila during the period 2008-2009. This period includes the L'Aquila 2009 seismic sequence, where the main shock of 6 April heavily damaged the medieval centre of the town and its surrounding area, causing 308 deaths, more than 1000 injuries and about 60,000 displaced people. Recently, several publications have documented the observation of precursory signals which occurred before the 6 April earthquake (e.g. Eftaxias et al., 2009, 2010), while others do not find any pre-earthquake anomaly (e.g. Villante et al., 2010; Di Lorenzo et al., 2011). In light of this, the goal of this study is to carry out further retrospective investigations. ULF magnetic field data are investigated by means of conventional analyses of magnetic polarization ratio, improved magnetic polarization ratio, and fractal analysis. In addition, total geomagnetic field data coming from the INGV Central Italy tectonomagnetic network have also been investigated, using the simple inter-station differentiation method. Within the limits of these methods, no magnetic anomalous signal which may be reasonably characterized as a precursor of the L'Aquila earthquakes has been found.

  1. Effect of synthesis parameters on morphology of polyaniline (PANI) and field emission investigation of PANI nanotubes

    NASA Astrophysics Data System (ADS)

    Bankar, Prashant K.; Patil, Sandip S.; More, Mahendra A.

    2015-06-01

    Polyaniline (PANI) nanostructures have been synthesized by simple chemical oxidation route at different monomer concentration along with variation in synthesis temperature. The effect of variation of synthesis parameters has been revealed using different characterization techniques. The structural and morphological characterization of the synthesized PANI nanostructures was carried out by scanning electron microscopy (SEM), transmission electron microscopy (TEM), whereas Fourier Transform Infrared spectroscopy (FTIR) has been used to reveal the chemical properties. With the variation in the synthesis temperature and monomer concentration, various morphologies characterized by formation of PANI nanoparticles, nanofibres, nanotubes and nanospheres, are revealed from the SEM analysis. The FTIR analysis reveals the formation of conducting state of PANI under prevailing experimental conditions. The field emission investigation of the conducting PANI nanotubes was performed in all metal UHV system at base pressure of 1x10-8 mbar. The turn on field required to draw emission of 1 nA current was observed to be ˜ 2.2 V/μm and threshold field (corresponding to emission current density of 1 µA/cm2) was found to be 3.2 V/μm. The emission current was observed to be stable for more than three hours at a preset value 1 µA. The simple synthesis route and good field emission characteristics indicate potential of PANI nanofibres as a promising emitter for field emission based micro/nano devices.

  2. Results of investigations at the Zunil geothermal field, Guatemala: Well logging and brine geochemistry

    SciTech Connect

    Adams, A.; Dennis, B.; Van Eeckhout, E.; Goff, F.; Lawton, R.; Trujillo, P.E.; Counce, D.; Archuleta, J. ); Medina, V. . Unidad de Desarollo Geotermico)

    1991-07-01

    The well logging team from Los Alamos and its counterpart from Central America were tasked to investigate the condition of four producing geothermal wells in the Zunil Geothermal Field. The information obtained would be used to help evaluate the Zunil geothermal reservoir in terms of possible additional drilling and future power plant design. The field activities focused on downhole measurements in four production wells (ZCQ-3, ZCQ-4, ZCQ-5, and ZCQ-6). The teams took measurements of the wells in both static (shut-in) and flowing conditions, using the high-temperature well logging tools developed at Los Alamos National Laboratory. Two well logging missions were conducted in the Zunil field. In October 1988 measurements were made in well ZCQ-3, ZCQ-5, and ZCQ-6. In December 1989 the second field operation logged ZCQ-4 and repeated logs in ZCQ-3. Both field operations included not only well logging but the collecting of numerous fluid samples from both thermal and nonthermal waters. 18 refs., 22 figs., 7 tabs.

  3. Spectroscopic investigation of fast (ns) magnetic field penetration in a plasma

    NASA Astrophysics Data System (ADS)

    Sarfaty, M.; Shpitalnik, R.; Arad, R.; Weingarten, A.; Krasik, Ya. E.; Fruchtman, A.; Maron, Y.

    1995-06-01

    The time-dependent magnetic field spatial distribution in a coaxial positive-polarity plasma opening switch (POS) carrying a current ≂135 kA during ≂100 ns, was investigated by two methods. In the first, ionic line emission was observed simultaneously for two polarizations to yield the Doppler and Zeeman contributions to the line profiles. In the second method, the axial velocity distribution of ions was determined, giving the magnetic field through the ion equation of motion. This method requires knowledge of the electron density, here obtained from the observed particle ionization times. To this end, a lower bound for the electron kinetic energy was determined using various line intensities and time-dependent collisional-radiative calculations. An important necessity for POS studies is the locality of all measurements in r, z, and θ. This was achieved by using laser evaporation to seed the plasma nonperturbingly with the species desired for the various measurements. The Zeeman splitting and the ion motion showed magnetic field penetration through the 3.5 cm long plasma at a velocity ≂108 cm/s. The current density was found to be relatively high at the load-side edge of the switch plasma. It is suggested that this may cause plasma acceleration into the vacuum section toward the load, which is supported by charge-collector measurements. The fast magnetic field penetration agrees with estimates based on the Hall-field mechanism.

  4. Effect of synthesis parameters on morphology of polyaniline (PANI) and field emission investigation of PANI nanotubes

    SciTech Connect

    Bankar, Prashant K.; More, Mahendra A.; Patil, Sandip S.

    2015-06-24

    Polyaniline (PANI) nanostructures have been synthesized by simple chemical oxidation route at different monomer concentration along with variation in synthesis temperature. The effect of variation of synthesis parameters has been revealed using different characterization techniques. The structural and morphological characterization of the synthesized PANI nanostructures was carried out by scanning electron microscopy (SEM), transmission electron microscopy (TEM), whereas Fourier Transform Infrared spectroscopy (FTIR) has been used to reveal the chemical properties. With the variation in the synthesis temperature and monomer concentration, various morphologies characterized by formation of PANI nanoparticles, nanofibres, nanotubes and nanospheres, are revealed from the SEM analysis. The FTIR analysis reveals the formation of conducting state of PANI under prevailing experimental conditions. The field emission investigation of the conducting PANI nanotubes was performed in all metal UHV system at base pressure of 1x10{sup −8} mbar. The turn on field required to draw emission of 1 nA current was observed to be ∼ 2.2 V/μm and threshold field (corresponding to emission current density of 1 µA/cm2) was found to be 3.2 V/μm. The emission current was observed to be stable for more than three hours at a preset value 1 µA. The simple synthesis route and good field emission characteristics indicate potential of PANI nanofibres as a promising emitter for field emission based micro/nano devices.

  5. Investigations of thermal conductivity of metals in the field of centrifugal and vibration accelerations

    NASA Astrophysics Data System (ADS)

    Lepeshkin, A. R.; Vaganov, P. A.

    2016-11-01

    The methods of investigations of a thermal conductivity of materials in the field of centrifugal radial and circumferential and vibration accelerations have been developed. The setup for investigation of thermophysical characteristics properties of materials on a spin rig, using a vacuum chamber, under the influence of centrifugal radial and circumferential accelerations and on a vibration rig under the influence of vibration accelerations have been proposed. The results of the investigations of an unsteady thermal state of heat-conductors (metal samples) in the field of centrifugal and vibration accelerations are given. From the analysis of the results of experimental investigations one can conclude that the thermal conductivity of the heat-conductors increases significantly by increasing the rotation frequency or amplitude of oscillations in comparison with a steady state. Thus, this increase of the thermal conductivity is associated with an increase of the electron drift velocity under the influence of centrifugal and vibration accelerations according to Wiedemann-Franz law. The results obtained are of practical importance for the calculations of the thermal state of the rotating parts of aircraft engines and other energy turbomachines.

  6. Exploring Faculty Retirement Issues in Public 2-Year Institutions

    ERIC Educational Resources Information Center

    Conley, Valerie Martin

    2005-01-01

    Much of the research on faculty retirement focuses exclusively on 4-year institutions. This study fills a gap by describing the age distribution of faculty in public 2-year institutions, the retirement plans of these faculty, and factors related to the retirement decision-making process using data from the 1999 National Study of Postsecondary…

  7. Childhood Bereavement: Psychopathology in the 2 Years Postparental Death

    ERIC Educational Resources Information Center

    Cerel, Julie; Fristad, Mary A.; Verducci, Joseph; Weller, Ronald A.; Weller, Elizabeth B.

    2006-01-01

    Objective: Although the death of a parent is one of the most significant stressors a child can experience, the psychiatric sequelae of parental death are not fully understood. Method: A total of 360 parent-bereaved children (ages 6-17) and their surviving parents were directly interviewed four times during the first 2 years following the death (at…

  8. Triadic Interaction among Newly Acquainted 2-Year-Olds

    ERIC Educational Resources Information Center

    Ishikawa, Fumiko; Hay, Dale F.

    2006-01-01

    Are children as young as 2 years old able to interact in groups of three? The study applied the family triad model first introduced by Parke, Power, and Gottman (1979) to the case of peer interaction. In Experiment 1, the model was refined for use in studies of peer interaction and applied to an existing dataset of 16 triads of newly acquainted…

  9. [Constrictive pericarditis in children under 2 years of age].

    PubMed

    Silva, Lia; Anjos, Rui; Martins, Fernando Maymone; Telo, Margarida

    2002-01-01

    Two cases of constrictive pericarditis, in children under 2 years of age, of non-tuberculosis aetiology, diagnosed from June 97 to May 98 are reported. This entity is rare in paediatrics and it may progress to severe condition. Surgical treatment has a low risk and is generally associated with good prognosis. Aetiology, clinic presentation, differential diagnosis with restrictive cardiomyopathy and treatment are discussed.

  10. Intensity Accents in French 2 Year Olds' Speech.

    ERIC Educational Resources Information Center

    Allen, George D.

    The acoustic features and functions of accentuation in French are discussed, and features of accentuation in the speech of French 2-year-olds are explored. The four major acoustic features used to signal accentual distinctions are fundamental frequency of voicing, duration of segments and syllables, intensity of segments and syllables, and…

  11. Investigations of Non-Thermal Interactions Between Microwave Fields and Ionic Ceramic Materials

    NASA Astrophysics Data System (ADS)

    Freeman, Samuel Anthony

    Reports of enhanced mass transport and solid-state reaction rates during microwave processing have been reported in the literature for a variety of ceramic, glass, and polymer materials. These empirical observations of microwave enhancements have been broadly called the "microwave effect," even though no satisfactory theory existed to explain them. This dissertation describes a series of theoretical and experimental investigations of possible causes for enhanced mass transport in ceramic materials heated in microwave furnaces. The scientific method followed was to examine many of the assumptions used (either implicitly or explicitly) in the models and rate equations of mass transport processes and to challenge some of these assumptions in light of the conditions existing in microwave-heated materials. the investigations fall into two categories: (1) studies of enhanced mass transport coefficients; and (2) studies of enhanced driving forces. The investigations of increased transport coefficients first considered two temperature issues. Temperature measurement of a microwave-heated object is nontrivial, and so some consideration of temperature mismeasurement effects is described. Furthermore, the average thermal energy may not be completely related to the probability of high-energy diffusion events; therefore the possibility of athermal energy distributions is examined. Finally, the microwave field effects on activation energy barriers (and therefore diffusion probabilities) is considered. Experimental investigations of these effects using ionic current measurements is also described. Both the theoretical an experimental results indicate that transport coefficients are not affected by microwave heating, although temperature mismeasurement can account for some apparent enhancement. For microwave-enhanced driving forces, transport driven by temperature gradients in microwave-heated bodies is first examined and found to be unimportant. However, a new model for a

  12. Original Size of the Sudbury Structure: Evidence from Field Investigations and Imaging Radar

    NASA Technical Reports Server (NTRS)

    Lowmman, Paul D., Jr.

    1999-01-01

    This paper summarizes results of continuing studies of the original size of the Sudbury impact structure, including imaging radar and field investigations of supposed "Sudbury breccia" north of the Sudbury Igneous Comples (SIC). Imaging radar acquired from Canada Centre for Remote Sensing (CCRS) aircraft, European Space Agency Remote Sensing Satellite (ERS-1), and RADARSAT shows no evidence of outer rings concentric with the North Range. Illumination directions are such that these rings, presumably extension fractures, would be conspicuous by look azimuth highlighting if they existed. Field mapping supports this interpretation, showing that supposed ring fractures occupied by Huronian sediments are essentially synclines older than the 1850 Ma impact and are not related to the impact. Field investigations of "Sudbury breccia" north of the SIC shows that most if not all of it is inside or along contacts with diabase dykes of the Sudbury Swarm (ca. 1238 Ma), and hence is far too young to be related to the impact. A recently-discovered occurrence of "Sudbury breccia" south of the SIC, near Creighton, is similarly associated with a NW-trending diabase dyke cutting the SIC, supporting the post-impact age of the breccia. It is concluded that the original north rim of the Sudbury crater was not more than 5 to 10 km north of the present North Range SIC contact, and that published estimates of the crater size (ca 200 km diameter) are incorrect.

  13. Investigation of the three-dimensional flow field within a transonic fan rotor: Experiment and analysis

    NASA Technical Reports Server (NTRS)

    Pierzga, M. J.; Wood, J. R.

    1984-01-01

    An experimental investigation of the three dimensional flow field through a low aspect ratio, transonic, axial flow fan rotor has been conducted using an advanced laser anemometer (LA) system. Laser velocimeter measurements of the rotor flow field at the design operating speed and over a range of through flow conditions are compared to analytical solutions. The numerical technique used herein yields the solution to the full, three dimensional, unsteady Euler equations using an explicit time marching, finite volume approach. The numerical analysis, when coupled with a simplified boundary layer calculation, generally yields good agreement with the experimental data. The test rotor has an aspect ratio of 1.56, a design total pressure ratio of 1.629 and a tip relative Mach number of 1.38. The high spatial resolution of the LA data matrix (9 radial by 30 axial by 50 blade to blade) permits details of the transonic flow field such as shock location, turning distribution and blade loading levels to be investigated and compared to analytical results.

  14. Field investigation of a wake structure downwind of a VAWT in a windfarm array

    SciTech Connect

    Liu, H.T.; Buck, J.W.; Germain, A.C.; Hinchee, M.E.; Solt, T.S.; LeRoy, G.M.; Srnsky, R.A.

    1987-10-01

    The effects of upwind turbine wakes on the performance of a FloWind 17-m VAWT were investigated through a series of field experiments conducted at the FloWind windfarm on Cameron Ridge, Tehachapi, California. The field experiment was conducted within a VAWT array consisting of more than nine VAWTs with separations 3D crosswised by 8D downwind (where D is the turbine diameter) in a staggered configuration. The array is the upwind three rows of VAWTS in a total of six rows that are on top of the Cameron Ridge plateau. The terrain features in the vicinity are reasonably regular, with an upslope of 7 deg on the average; however, several local irregularities are present. The annual hourly averaged wind speed exceeds 8 m/s at the site. The wind field and the power-outputs of nine turbines within the array were measured with wind sensors and power transducers. Nine Gill propeller and 18 Maximum cup anemometers and one direction sensor were mounted on portable and stack-up towers installed upwind and within the turbine array. From the field measurements, the velocity and power/energy deficits were derived under various turbine on/off configurations. Much information was provided to characterize the structure of VAWT wakes and to assess their effects on the performance of downwind turbines. Recommendations are made for optimizing windfarm design and operations as well as for wind energy management.

  15. An Investigation of the Effects of Inhomogenous Electric Fields on Gravitation

    NASA Astrophysics Data System (ADS)

    Yin, Ming; Dimofte, Andreea; Bleiweiss, Michael; Saygi, Salih; Vargas, Jose; Datta, Timir

    2000-04-01

    Despite a flurry of measurements of Newton’s gravitational constant, G, that took place in the last decade, the relative standard uncertainty of the present CODATA value of G is 12 times larger than it was in the late eighties. Vargas and Torr have suggested that these discrepancies may be due to the influence of electric fields (Found. Phys. 29, 145, 1999) associated with the experiments. They predict measurable deformations of the spacetime structure (STS), i.e. gravitational forces, to be produced by inhomogeneous electromagnetic fields additional to those previously known. This effect, if present, is unlikely to have been serendipitously discovered. To test the possibility of affecting the local STS by nonuniform electromagnetic fields, we are investigating the weight force of test probes with a system having a weight resolution of 100ppb (A. Dimofte, M.S. thesis, USC 1999). Different field geometries and test mass compisition are tested. The apparatus and analysis are designed to sort out the electrostatic contributions from any possible gravito-electric effects. Further work to improve the quality and reproducibilty of the signal is in progress. The results from this work will be presented.

  16. Investigating Non-Equilibrium Fluctuations of Nanocolloids in a Magnetic Field Using Direct Imaging Methods

    NASA Astrophysics Data System (ADS)

    Rice, Ashley; Oprisan, Ana; Oprisan, Sorinel; Rice-Oprisan College of Charleston Team

    Nanoparticles of iron oxide have a high surface area and can be controlled by an external magnetic field. Since they have a fast response to the applied magnetic field, these systems have been used for numerous in vivo applications, such as MRI contrast enhancement, tissue repair, immunoassay, detoxification of biological fluids, hyperthermia, drug delivery, and cell separation. We performed three direct imaging experiments in order to investigate the concentration-driven fluctuations using magnetic nanoparticles in the absence and in the presence of magnetic field. Our direct imaging experimental setup involved a glass cell filled with magnetic nanocolloidal suspension and water with the concentration gradient oriented against the gravitational field and a superluminescent diode (SLD) as the light source. Nonequilibrium concentration-driven fluctuations were recorded using a direct imaging technique. We used a dynamic structure factor algorithm for image processing in order to compute the structure factor and to find the power law exponents. We saw evidence of large concentration fluctuations and permanent magnetism. Further research will use the correlation time to approximate the diffusion coefficient for the free diffusion experiment. Funded by College of Charleston Department of Undergraduate Research and Creative Activities SURF grant.

  17. Investigating the impact of electromagnetic fields on human cells: A thermodynamic perspective

    NASA Astrophysics Data System (ADS)

    Lucia, Umberto; Ponzetto, Antonio; Deisboeck, Thomas S.

    2016-02-01

    The consequences of the interactions of electromagnetic waves, as used in conventional MRI technology, with human cells are not fully understood. To analyze these interactions, a novel thermodynamic approach is presented that is based on the relationship between electromagnetic and thermodynamic quantities. The theoretical results indicate that the waves' impact is largest at high magnetic field strengths and at low frequencies. This is the first step towards a clinically useful framework to quantitatively assess MRI impact including a potential trade-off between the desired increase in spatial resolution that higher magnetic field strengths yield for diagnostic purposes and the danger this may pose for cell membranes, and by extension, for the tissues investigated.

  18. Russian investigations in the field of atmospheric radiation in 2011-2014

    NASA Astrophysics Data System (ADS)

    Timofeev, Yu. M.; Shul'gina, E. M.

    2016-09-01

    A short survey prepared by the Russian Commission on Atmospheric Radiation contains the most significant results of work in the field of atmospheric-radiation studies performed in 2011-2014. It is part of the Russian National Report on Meteorology and Atmospheric Sciences prepared for the International Association on Meteorology and Atmospheric Sciences (IAMAS)1. During this period, the Russian Commission on Atmospheric Radiation, jointly with the concerned departments and organizations, organized two International Symposiums on Radiation and Dynamics (ISARD-2011 and ISARD-2013). At these conferences, the central problems in modern atmospheric physics were discussed: radiative transfer (RT) and atmospheric optics; greenhouse gases, clouds, and aerosols; remote methods of measurements; and new measurement data. This survey presents six directions covering the whole spectrum of investigations performed in the field of atmospheric radiation.

  19. Russian investigations in the field of atmospheric radiation in 2007-2010

    NASA Astrophysics Data System (ADS)

    Timofeev, Yu. M.; Shul'gina, E. M.

    2013-01-01

    A short survey prepared by the Russian Commission on Atmospheric Radiation contains the most significant results of works in the field of atmospheric-radiation studies performed in 2007-2010. It is part of the Russian National Report on Meteorology and Atmospheric Sciences prepared for the International Association on Meteorology and Atmospheric Sciences (IAMAS). During this period, the Russian Commission on Atmospheric Radiation, jointly with concerned departments and organizations, ran the conference "Physics and Education," dedicated to the 75th anniversary of the Department of Physics at St. Petersburg State University (2007); the International Symposium of CIS Countries "Atmospheric Radiation and Dynamics" (2009); and the 5th International Conference "Atmospheric Physics, Climate, and Environment" (2010). At the conferences, central problems in modern atmosphere physics were discussed: radiative transfer and atmospheric optics; greenhouse gases, clouds, and aerosols; remote methods of measurements; and new measurement data. This survey presents five directions covering the whole spectrum of investigations performed in the field of atmospheric radiation.

  20. Design and implementation of epidemiological field investigation method based on mobile collaboration

    NASA Astrophysics Data System (ADS)

    Zhang, Lihui; Wang, Dongchuan; Huang, Mingxiang; Gong, Jianhua; Fang, Liqun; Cao, Wuchun

    2008-10-01

    With the development of mobile technologies and the integration with the spatial information technologies, it becomes possible to provide a potential to develop new techno-support solutions to Epidemiological Field Investigation especially for the disposal of emergent public health events. Based on mobile technologies and virtual geographic environment, the authors have designed a model for collaborative work in four communication patterns, namely, S2S (Static to Static), M2S (Mobile to Static), S2M (Static to Mobile), and M2M (Mobile to Mobile). Based on the model mentioned above, this paper stresses to explore mobile online mapping regarding mobile collaboration and conducts an experimental case study of HFRS (Hemorrhagic Fever with Renal Syndrome) fieldwork, and then develops a prototype system of emergent response disposition information system to test the effectiveness and usefulness of field survey based on mobile collaboration.

  1. Ground-based complex for detection and investigation of fast optical transients in wide field

    NASA Astrophysics Data System (ADS)

    Molinari, Emilio; Beskin, Grigory; Bondar, Sergey; Karpov, Sergey; Plokhotnichenko, Vladimir; de-Bur, Vjacheslav; Greco, Guiseppe; Bartolini, Corrado; Guarnieri, Adriano; Piccioni, Adalberto

    2008-07-01

    To study short stochastic optical flares of different objects (GRBs, SNs, etc) of unknown localizations as well as NEOs it is necessary to monitor large regions of sky with high time resolution. We developed a system which consists of wide-field camera (FOW is 400-600 sq.deg.) using TV-CCD with time resolution of 0.13 s to record and classify optical transients, and a fast robotic telescope aimed to perform their spectroscopic and photometric investigation just after detection. Such two telescope complex TORTOREM combining wide-field camera TORTORA and robotic telescope REM operated from May 2006 at La Silla ESO observatory. Some results of its operation, including first fast time resolution study of optical transient accompanying GRB and discovery of its fine time structure, are presented. Prospects for improving the complex efficiency are given.

  2. An investigation of magnetic field effects on plume density and temperature profiles of an applied-field MPD thruster

    NASA Technical Reports Server (NTRS)

    Bullock, S. Ray; Myers, R. M.

    1994-01-01

    Applied-field magnetoplasmadynamic (MPD) thruster performance is below levels required for primary propulsion missions. While MPD thruster performance has been found to increase with the magnitude of the applied-field strength, there is currently little understanding of the impact of applied-field shape on thruster performance. The results of a study in which a single applied-field thruster was operated using three solenoidal magnets with diameters of 12.7, 15.2, and 30.4-cm are presented. Thruster voltage and anode power deposition were measured for each applied field shape over a range of field strengths. Plume electron number density and temperature distributions were measured using a Langmuir probe in an effort to determine the effect of field shape on plume confinement by the diverging magnetic-field for each of the three magnetic field shapes. Results show that the dependence of the measured thruster characteristics on field shape were non-monotonic and that the field shape had a significant effect on the plume density and temperature profiles.

  3. Limited field investigation report for the 100-DR-1 Operable Unit

    SciTech Connect

    Not Available

    1994-06-01

    This limited field investigation (LFI) report summarizes the data collection and analysis activities conducted during the 100-DR-1 Source Operable Unite LFI and the associated qualitative risk assessment (QRA), and makes recommendations on the continued candidacy of high-priority sites for interim remedial measures (IRM). The results and recommendations presented in this report are generally independent of future land use scenarios. The 100-DR-1 Operable Unit is one of four operable units associated with the 100 D/DR Area at the Hanford Site. The 100-DR-1 Operable Unit encompasses approximately 1.5 km{sup 2} (0.59 mi{sup 2}) and is located immediately adjacent to the Columbia River shoreline. In general, it contains waste facilities associated with the original plant facilities constructed to support D Reactor facilities, as well as cooling water retention basin systems for both D and DR Reactors. The 100-DR-1 LFI began the investigative phase of the remedial investigation for a select number of high-priority sites. The LFI was performed to provide additional data needed to support selection, design and implementation of IRM, if needed. The LFI included data compilation, nonintrusive investigations, intrusive investigations, summarization of 100 Area aggregate studies, and data evaluation.

  4. Using SAR and LAM Wind Fields to Investigate the Effects of Land/Atmosphere Interaction

    NASA Astrophysics Data System (ADS)

    Zecchetto, Stefano; De Biasio, Francesco; Miglietta, Mario Marcello; Biamino, Walter

    2010-12-01

    Modern satellite-borne synthetic aperture radar (SAR) images provide datasets at exceptionally high spatial resolutions, appropriate for investigating the mesoscale phenomena in the marine atmospheric boundary layer. Due to the still unsolved problems in the methodologies of wind field retrieval, and the poor temporal coverage at mid-latitudes offered by present SARs, the use of such wind fields is still limited. A fruitful application concerns the combined use of SAR and the hindcasts provided by limited area models, to study the effects of the land/atmosphere interaction. This has been carried out over an area, about 400 km by 400 km wide, around the Crete island in the eastern Mediterranean Sea, a region subject to complex wind patterns, due to the interaction of the almost steady northerly Etesian wind with the orography of the many islands in the region. The Weather Research & Forecasting (WRF) atmospheric model has been used to hindcast the wind field at a horizontal resolution of 1 km over the area imaged by an Envisat ASAR image, from which the wind field has been extracted using a methodology based on the two-dimensional continuous wavelet transform. The 10 m wind fields resulting from the numerical simulations, carried out using different diffusion and boundary layer parameterization schemes, have been compared to the SAR-derived one, in order to select the most appropriate scheme, to analyze the correspondence of the observed and the simulated wind structures, and to evaluate the differences in direction and speed. Such a comparison has shown the possible benefits for both the modelling and SAR-wind extraction activities.

  5. [Environmental investigation of ground water contamination at Wright-Patterson Air Force Base, Ohio]. Volume 5, Appendix A, Part 2, Field Investigation report

    SciTech Connect

    Not Available

    1992-03-01

    This report contains information related to the sampling and chemical analysis of ground water at the Wright-Patterson Air Force Base. It is part of a field investigation of ground water contamination.

  6. Experimental Investigation of Laser Transmission Welding of Thermoplastics with Part-Adapted Temperature Fields

    NASA Astrophysics Data System (ADS)

    Devrient, M.; Kern, M.; Jaeschke, P.; Stute, U.; Haferkamp, H.; Schmidt, M.

    Laser transmission welding is known for high flexibility, extraordinary potential for process automation and outstanding weld seam properties. Problems may occur due to the poor gap-bridging capability of contour welding. Gaps of a few tens of microns can lead to processing issues such as welding failures, poor achievable process speed or low weld seam strengths. To overcome this, laser transmission welding with part-adapted temperature fields was developed, and is experimentally investigated here. Results concerning the process behavior, dependent on several oscillation types of the laser beam, as well as achieved tensile shear strengths and the monitored gap-bridging capability are presented.

  7. Investigation of defect-induced abnormal body current in fin field-effect-transistors

    SciTech Connect

    Liu, Kuan-Ju; Tsai, Jyun-Yu; Lu, Ying-Hsin; Liu, Xi-Wen; Chang, Ting-Chang; Chen, Ching-En; Yang, Ren-Ya; Cheng, Osbert; Huang, Cheng-Tung

    2015-08-24

    This letter investigates the mechanism of abnormal body current at the linear region in n-channel high-k/metal gate stack fin field effect transistors. Unlike body current, which is generated by impact ionization at high drain voltages, abnormal body current was found to increase with decreasing drain voltages. Notably, the unusual body leakage only occurs in three-dimensional structure devices. Based on measurements under different operation conditions, the abnormal body current can be attributed to fin surface defect-induced leakage current, and the mechanism is electron tunneling to the fin via the defects, resulting in holes left at the body terminal.

  8. Contactless electromodulation investigations of surface/interface electric fields in semiconductor microstructures

    SciTech Connect

    Pollak, F.H.

    1993-07-01

    This article reviews some recent experiments using contactless electromodulation techniques, i.e., photoreflectance and contactless electroreflectance, to investigate the surface/interface electric fields in (a) pseudomorphic GaAlAs/InGaAs/GaAs modulation-doped quantum well structures (including the determination of the two-dimensional electron gas density) and (b) Fermi-level pinning on n- and p-type GaAs (001) surfaces. Evidence for the reduced surface state density on p-type material will be presented from both prior and new experiments. 25 refs., 4 figs., 1 tab.

  9. Experimental Investigation of Pool Boiling Heat Transfer Enhancement in Microgravity in the Presence of Electric Fields

    NASA Technical Reports Server (NTRS)

    Herman, Cila

    1996-01-01

    compared to values obtained for the same system without electric fields. Imposing an external electric field holds the promise to improve pool boiling heat transfer in low gravity, since a phase separation force other than gravity is introduced. The goal of our research is to experimentally investigate the potential of EHD and the mechanisms responsible for EHD heat transfer enhancement in boiling in low gravity conditions.

  10. Flux-gate magnetic field sensor based on yttrium iron garnet films for magnetocardiography investigations

    NASA Astrophysics Data System (ADS)

    Vetoshko, P. M.; Gusev, N. A.; Chepurnova, D. A.; Samoilova, E. V.; Syvorotka, I. I.; Syvorotka, I. M.; Zvezdin, A. K.; Korotaeva, A. A.; Belotelov, V. I.

    2016-08-01

    A new type of f lux-gate vector magnetometer based on epitaxial yttrium iron garnet films has been developed and constructed for magnetocardiography (MCG) investigations. The magnetic field sensor can operate at room temperature and measure MCG signals at a distance of about 1 mm from the thoracic cage. The high sensitivity of the sensor, better than 100 fT/Hz1/2, is demonstrated by the results of MCG measurements on rats. The main MCG pattern details and R-peak on a level of 10 pT are observed without temporal averaging, which allows heart rate anomalies to be studied. The proposed magnetic sensors can be effectively used in MCG investigations.

  11. Investigation of Fully Three-Dimensional Helical RF Field Effects on TWT Beam/Circuit Interaction

    NASA Technical Reports Server (NTRS)

    Kory, Carol L.

    2000-01-01

    A fully three-dimensional (3D), time-dependent, helical traveling wave-tube (TWT) interaction model has been developed using the electromagnetic particle-in-cell (PIC) code MAFIA. The model includes a short section of helical slow-wave circuit with excitation fed by RF input/output couplers, and electron beam contained by periodic permanent magnet (PPM) focusing. All components of the model are simulated in three dimensions allowing the effects of the fully 3D helical fields on RF circuit/beam interaction to be investigated for the first time. The development of the interaction model is presented, and predicted TWT performance using 2.5D and 3D models is compared to investigate the effect of conventional approximations used in TWT analyses.

  12. Metabolic Investigation in Gluconacetobacter xylinus and Its Bacterial Cellulose Production under a Direct Current Electric Field.

    PubMed

    Liu, Miao; Zhong, Cheng; Zhang, Yu Ming; Xu, Ze Ming; Qiao, Chang Sheng; Jia, Shi Ru

    2016-01-01

    The effects of a direct current (DC) electric field on the growth and metabolism of Gluconacetobacter xylinus were investigated in static culture. When a DC electric field at 10 mA was applied using platinum electrodes to the culture broth, bacterial cellulose (BC) production was promoted in 12 h but was inhibited in the last 12 h as compared to the control (without DC electric field). At the cathode, the presence of the hydrogen generated a strong reductive environment that is beneficial to cell growth. As compared to the control, the activities of glycolysis and tricarboxylic acid cycle, as well as BC productivity were observed to be slightly higher in the first 12 h. However, due to the absence of sufficient oxygen, lactic acid was accumulated from pyruvic acid at 18 h, which was not in favor of BC production. At the anode, DC inhibited cell growth in 6 h when compared to the control. The metabolic activity in G. xylinus was inhibited through the suppression of the tricarboxylic acid cycle and glycolysis. At 18-24 h, cell density was observed to decrease, which might be due to the electrolysis of water that significantly dropped the pH of cultural broth far beyond the optimal range. Meanwhile, metabolites for self-protection were accumulated, for instance proline, glutamic acid, gluconic acid, and fatty acids. Notably, the accumulation of gluconic acid and lactic acid made it a really tough acid stress to cells at the anode and finally led to depression of cell growth.

  13. Investigating the impact of visuohaptic simulations for the conceptual understanding of electric field for distributed charges

    NASA Astrophysics Data System (ADS)

    Shaikh, Uzma Abdul Sattar

    The present study assessed the benefits of a multisensory intervention on the conceptual understanding of electric field for distributed charges in engineering and technology undergraduate students. A novel visuohaptic intervention was proposed, which focused on exploring the forces around the different electric field configurations for distributed charges namely point, infinitely long line and uniformly charged ring. The before and after effects of the visuohaptic intervention are compared, wherein the intervention includes instructional scaffolding. Three single-group studies were conducted to investigate the effect among three different populations: (a) Undergraduate engineering students, (b) Undergraduate technology students and (c) Undergraduate engineering technology students from a different demographic setting. The findings from the three studies suggests that the haptic modality intervention provides beneficial effects by allowing students to improve their conceptual understanding of electric field for distributed charges, although students from groups (b) and (c) showed a statistically significant increase in the conceptual understanding. The findings also indicate a positive learning perception among all the three groups.

  14. Effective use of field screening techniques in environmental investigations: A multivariate geostatistical approach

    SciTech Connect

    Wild, M.R.; Rouhani, S.

    1996-12-31

    Environmental investigations typically entail broad data gathering efforts which include field screening surveys and laboratory analyses. Although usually collected extensively, data from field screening surveys are rarely used in the actual delineation of media contamination. On the other hand, laboratory analyses, which are used in the delineation, are minimized to avoid potentially high cost. Multivariate geostatistical techniques, such as indicator cokriging, were employed to incorporate volatile organic screening and laboratory data in order to better estimate soil contamination concentrations at an underground storage tank site. In this work, the direct and cross variographies are based on a multi-scale approach. The results indicate that soil gas measurements show good correlations with laboratory data at large scales. These correlations however, can be masked by poor correlations at micro-scale distances. Consequently, a classical direct correlation analysis between the two measured values is very likely to fail. In contrast, the presented multi-scale co-estimation procedure provides tools for a cost-effective and reliable assessment of soil contamination based on a combined use of laboratory and field screening data.

  15. Experimental and theoretical investigation of implantable cardiac pacemaker exposed to low frequency magnetic field.

    PubMed

    Babouri, A; Hedjeidj, A; Guendouz, L

    2009-04-01

    This paper presents in vitro investigation of an implantable cardiac pacemaker exposed to low frequency magnetic fields. The method used in this study is based on the interaction by inductive coupling through the loop formed by the pacemaker and its loads and the surrounding medium. This interaction results in an induced electromotive force between the terminals of the pacemaker, which can potentially disturb its operation. The studied frequencies are 50/60 Hz and 10/25 kHz. The experimental tests were carried out on several cardiac pacemakers, single chamber, and dual chamber. The results show a window effect of the detection circuits of cardiac pacemakers for the four studied frequencies. The modelling of the test bed requires studying the effects of the induced currents generated by the application of a magnetic field. Analytical calculations and Numerical simulations were carried out. We modelled the interactions of the magnetic field with a simplified representation of pacemaker embedded in the medium. The comparison of the results in the air and in vitro enabled us to make an equivalent electric model. The results obtained in experimental and theoretical studies allowed us to validate the test bed. The method applied is valid for other medical implants such as cardiac defibrillators, implant hearing aids system...etc.

  16. Radioactive waste storage in mined caverns in crystalline rock: results of field investigations at Stripa, Sweden

    SciTech Connect

    Witherspoon, P.A.

    1980-10-01

    It is generally agreed that the most practicable method of isolating nuclear wastes from the biosphere is by deep burial in suitable geologic formations. Such burial achieves a high degree of physical isolation but raises questions concerning the rate at which some of these wastes may return to the biosphere through transport by groundwater. Any suitable repository site will be disturbed first by excavation and second by the thermal pulse caused by the radioactive decay of the wastes. To assess the effectiveness of geologic isolation it is necessary to develop the capability of predicting the response of a rock mass to such a thermal pulse. Ultimately, this requires field measurements below the surface in media representative of those likely to be encountered at an actual repository. Access to a granitic rock mass adjacent to a defunct iron ore mine at Stripa, Sweden, at a depth of about 350 m below surface has provided a unique opportunity to conduct a comprehensive suite of hydrological and thermo-mechanical experiments under such conditions. The results of these field tests have shown the importance of geologic structure and the functional dependence of the thermo-mechanical properties on temperature in developing a valid predictive model. The results have also demonstrated the vital importance of carrying out large-scale investigations in a field test facility.

  17. Experimental investigation of the flow field and pollen trajectories/deposition around ovulate pine cones

    NASA Astrophysics Data System (ADS)

    Jacobson, Neta-Lee; van Hout, René

    2014-11-01

    Particle deposition on bluff bodies is important both in industrial applications as well as in furthering our understanding of ecological networks. It has been hypothesized that plant structural morphology manipulates the flow field in order to enhance capturing of species-specific pollen and thereby increase fertilization chances. Here, the deposition mechanism of different pine pollen on freshly harvested ovulate pine cones (Pinus Halepensis/Brutia) was investigated using high speed, planar particle image velocimetry and holographic 3D technique enabling measurement of both Lagrangian particle tracks and instantaneous flow fields. Measurements were performed in a small blow-through windtunnel at Reynolds numbers ranging from Re = 174 to 767. The roughness on a pine cone is characterized by ``scales'' organized as Fibonacci spirals. Effects of this roughness on the flow field are compared to results for a smooth sphere at similar Re. Particle deposition results indicate that inertial deposition on the windward side of the cone is the main mechanism. However, at the lowest Reynolds numbers pollen with Stokes numbers less than one were entrained into the cone's near wake and advected towards the leeward side of the cone.

  18. Experimental and computational investigation of the NASA low-speed centrifugal compressor flow field

    NASA Technical Reports Server (NTRS)

    Hathaway, Michael D.; Chriss, Randall M.; Wood, Jerry R.; Strazisar, Anthony J.

    1993-01-01

    An experimental and computational investigation of the NASA Lewis Research Center's low-speed centrifugal compressor (LSCC) flow field was conducted using laser anemometry and Dawes' three-dimensional viscous code. The experimental configuration consisted of a backswept impeller followed by a vaneless diffuser. Measurements of the three-dimensional velocity field were acquired at several measurement planes through the compressor. The measurements describe both the throughflow and secondary velocity field along each measurement plane. In several cases the measurements provide details of the flow within the blade boundary layers. Insight into the complex flow physics within centrifugal compressors is provided by the computational fluid dynamics analysis (CFD), and assessment of the CFD predictions is provided by comparison with the measurements. Five-hole probe and hot-wire surveys at the inlet and exit to the impeller as well as surface flow visualization along the impeller blade surfaces provided independent confirmation of the laser measurement technique. The results clearly document the development of the throughflow velocity wake that is characteristic of unshrouded centrifugal compressors.

  19. Shemya AFB, Alaska 1992 IRP field investigation report. Volume 4, Appendixes E and F: Final report

    SciTech Connect

    Not Available

    1993-02-01

    The US Air Force is currently investigating 22 sites on Shemya Air Force Base (AFB) to determine if past spill and disposal activities have caused environmental damage. These investigations are being carried out under the Air Force`s Installation Restoration Program (IRP). Field investigations were performed in 1992 to obtain the information needed to assess what future actions will need to be carried out at each site. The island`s drinking water supply was also investigated. Activities completed at 10 selected sites included surface sampling to determine the lateral extent of contamination, subsurface sampling to determine the vertical extent of contamination, and the installation of well points and monitoring wells to determine the direction of groundwater flow and if the groundwater has been affected by a site. In addition, geophysical surveys were performed at most sites to identify site boundaries and check for the presence of buried metal, to be avoided during drilling activities. This report contains appendices E and F with information on the following: soil boring logs, and data validation of samples analyzed.

  20. Investigation of smoothness-increasing accuracy-conserving filters for improving streamline integration through discontinuous fields.

    PubMed

    Steffen, Michael; Curtis, Sean; Kirby, Robert M; Ryan, Jennifer K

    2008-01-01

    Streamline integration of fields produced by computational fluid mechanics simulations is a commonly used tool for the investigation and analysis of fluid flow phenomena. Integration is often accomplished through the application of ordinary differential equation (ODE) integrators--integrators whose error characteristics are predicated on the smoothness of the field through which the streamline is being integrated--smoothness which is not available at the inter-element level of finite volume and finite element data. Adaptive error control techniques are often used to ameliorate the challenge posed by inter-element discontinuities. As the root of the difficulties is the discontinuous nature of the data, we present a complementary approach of applying smoothness-enhancing accuracy-conserving filters to the data prior to streamline integration. We investigate whether such an approach applied to uniform quadrilateral discontinuous Galerkin (high-order finite volume) data can be used to augment current adaptive error control approaches. We discuss and demonstrate through numerical example the computational trade-offs exhibited when one applies such a strategy.

  1. An investigation into field effects of consciousness from the perspectives of Maharishi's Vedic Science and physics

    NASA Astrophysics Data System (ADS)

    Kleinschnitz, Kurt Warren

    1997-05-01

    A long-range field effect of consciousness has been reported repeatedly in the scientific literature over the past twenty years. This phenomenon is called the Maharishi Effect, after Maharishi Mahesh Yogi, the first to predict it. The Maharishi Effect is the phenomenon of improved societal trends resulting from the practice of the Transcendental Meditationoler program or group practice of the TM-Sidhioler program by a small fraction of a population. The Maharishi Effect is fundamentally a phenomenon of radiation of evolutionary influence arising from the enlivenment of pure consciousness, the unified field of natural law, in the perspective of Maharishi's Vedic Science. This perspective is corroborated by forty-three published or presented papers reporting on results of Maharishi Effect interventions world-wide at city, national, international, and global scales. Present day standard- model physics and physiology do not account for the outcomes of the research on the Maharishi Effect. Because the observed societal impact of the Maharishi Effect influence must be based in an impact on the individual, and investigators report detection of the effect in individual physiological measurements, a simple robust indicator for the effect might aid physiologists and physicists in the effort to extend their sciences to include such field effects of consciousness. Thus, this dissertation reports on two experiments investigating simple, robust, objective indicators for the effect. The dissertation concludes on a practical note with a description of the promise, available through concerted utilization of the knowledge and technologies of consciousness in Maharishi's Vedic Science, for enhanced national and global security in the face of unprecedented nuclear, biological, and genetic threats for which the modern sciences offer few sensible solutions. ftnolerTranscendental Meditation and TM-Sidhi are service marks registered in the United States Patent and Trademark Office

  2. Laboratory and Field Investigations of Dynamic Effects in Soil Water Retention Curve

    NASA Astrophysics Data System (ADS)

    Chiu, Yung-Chia; Tseng, Yen-Huiang; Ye, Jiun-Yan

    2015-04-01

    The unsaturated soil is a multi-phase system and the embedded physical mechanisms and chemical reactions are very complicated. The characteristics of groundwater flow and mechanisms of mass transport are still ambiguous so far. In order to fully understand the flow and transport in the unsaturated zone, the soil water retention curve plays an important role in description of water flow. However, the measurements and calculations of soil water retention curve are usually obtained under the static condition or steady state (equilibrium), in which the dynamic effects (non-equilibrium) are not considered, and the obtained relationship between capillary pressure and saturation is skeptical. Therefore, the sandbox experiments and field tests will be conducted to discuss the dynamic effects in the soil water retention curve and hysteresis effect in this study. In the laboratory, the relations between capillary pressure, saturation, the rate of change of water content, and dynamic constant are evaluated through different setting of boundary conditions and different sizes of particles. In the field, the tests are conducted to describe the soil water retention curve through the rain simulator and artificial evaporation. Besides, the dynamic dewpoint potentiameter is used to analyze the hysteresis effect of soil samples, and its results are compared with the results obtained from sandbox and field experiments. Finally, through a series of experiments, the relationship between capillary pressure and saturation under the dynamic effects is established, and the associated theories and mechanisms are discussed. The works developed in this study can provide as reference tools for the hydrogeological investigation and contaminated site remediation in the future. Keywords: capillary pressure, saturation, soil water retention curve, hysteresis, sandbox experiment, field test

  3. Paleoglacial history of Dronning Maud Land: Numerical modeling guiding field investigations in East Antarctica

    NASA Astrophysics Data System (ADS)

    Rogozhina, Irina; Bernales, Jorge; Häfliger, Tonio; Stroeven, Arjen; Harbor, Jonathan; Glasser, Neil; Fredin, Ola; Fabel, Derek; Hättestrand, Class

    2015-04-01

    Reconstructing and predicting the response of the Antarctic Ice Sheet to climate change is one of the major challenges facing the Earth Science community. Numerical models of ice sheets are a central component of work to address this challenge, and these models are tested and improved by comparing model predictions of past ice extents with field-based reconstructions (from geological and geomorphological data). However, there are critical gaps in our knowledge of past changes in ice elevation and extent in many regions of East Antarctica, including a large area of Dronning Maud Land. In addition, there exist significant uncertainties in regional climate history along the ice sheet margin due to remoteness of these areas from ice core locations where detailed reconstructions of past climate conditions have been performed. This leaves numerical models of regional glaciation history largely unconstrained. MAGIC-DML is a new Swedish-UK-US-Norwegian-German project that aims to reconstruct vertical changes in ice extent across Dronning Maud Land as the basis for constraining numerical models of ice sheet behavior. The focus of the two planned field seasons will be in areas that have been identified as being critical for differentiating between possible past ice sheet configuration and timing. Geological reconstruction will involve the identification, mapping, and dating of glacially sculpted bedrock, ice-marginal moraines, drift sheets and erratic boulders that provide evidence for past changes in ice levels over thousands to millions of years. Prior to the field investigations, the German team is performing a detailed high-resolution modeling of the paleoglacial history and identifying areas across Dronning Maud Land that are most sensitive to the uncertainties in regional climate history and the choice of model parameters. These modeling results will be used as a basis for planning and guiding the field campaigns in East Antarctica in 2015 and 2016.

  4. Investigation of fault structures from microseismicity in the Wairakei geothermal field, New Zealand

    NASA Astrophysics Data System (ADS)

    Kim, Jongchan; Boese, Carolin; Andrews, Jennifer; Sepulveda, Favian; Archer, Rosalind; Malin, Peter

    2014-05-01

    The Wairakei geothermal field is located in the centre of a NNE-trending rifting arc, called the Taupo Volcanic Zone (TVZ), New Zealand. In 1958, commercial production of electricity started at the Wairakei field, which currently holds the largest installed capacity of the TVZ (~375 MWe). For some operational reasons, large scale infield re-injection started in the mid 1990's (Otupu area; east of Wairakei) and further extended to the south (Karapiti area) in August 2011. Small scale re-injection trials have been also being conducted since 2012 (West of Wairakei). In total, 13 borehole seismometers have been installed in the Wairakei geothermal field since 2009 to support reservoir management and drilling strategies, and observe the reservoir response to production and injection. The range of installation depths is 65 m to 1,200 m. About 97% of the 7049 events recorded have magnitude ≤2, in the so-called micro-earthquake range, and locate above 6 km depth. The micro-seismicity distribution tends to be diffuse. Although some correlation with geological units and faults can be made, identification of distinct fractures is challenging. In this study, we investigate active fault structures from micro-seismic events occurring in the geothermal field between March 2009 and June 2013 using focal mechanism, clustering and double-difference relocation methods. We firstly calculate double-couple focal mechanism solutions from the micro-seismic data set using HASH. To reduce uncertainty of focal mechanism parameters, P-wave first motion polarities from 12 GeoNet stations installed in the vicinity of the Wairakei were combined with those of 13 Wairakei stations within the field. In total, 21 focal mechanisms with more than eight P-wave polarities have been computed. Most focal mechanisms are consistent in showing a NNE-trending nodal plane, and have normal or strike-slip mechanisms, coinciding well with the overall extensional tectonic regime and mapped active faults in the

  5. Hydraulic characterization of rocky subsurface using field infiltrometer measurements coupled with hydrogeophysical investigations

    NASA Astrophysics Data System (ADS)

    Caputo, M. C.; de Carlo, L.; de Benedictis, F.; Vurro, M.

    2009-04-01

    The shallow and/or karstic and fractured aquifers are among the most important water resources. At the same time, they are particularly vulnerable to contamination. A detailed scientific knowledge of the behavior of these aquifers is essential for the development of sustainable groundwater management. Different investigation methods have been developed with the aim to characterize the subsurface and to monitor the flow and solute transport in these hydrogeology systems. This study presents the results of an investigation method, that combine large infiltrometer measurements with elettrical resistivity profiles, carried out in two different experimental sites characterized by different hydrogeology systems. One site, close to Altamura a city in the South of Italy, is represented from karstic and fractured limestone that overlays the deep aquifer. This area has been affected by sludge waste deposits derived from municipal and industrial wastewater treatment plants. The second site, close to San Pancrazio Salentino town in Southern Italy also, is represented from a quarry of calcarenite that has been used as a dump of sludge of mycelium producted from pharmaceutical industry. In both these cases the waste disposal have caused soil-subsoil contamination. Knowledge of the flow rate of the unsaturated zone percolation is needed to investigate the vertical migration of pollutants and the vulnerability of the aquifers. In this study, subsurface electrical resistivity measurements were used to visualize the infiltration of water in the subsoil due to unsaturated water flow. Simultaneously, the vertical flow was investigated by measuring water levels during infiltrometer tests carried out using a large adjustable ring infiltrometer, designed to be installed in the field directly on the outcrop of rock. In addition electrical resistivity azimuthal surveys have been conducted to detect principal fractures strike directions that cause preferential flow. The results obtained

  6. Source evaluation report phase 2 investigation: Limited field investigation. Final report: United States Air Force Environmental Restoration Program, Eielson Air Force Base, Alaska

    SciTech Connect

    Not Available

    1994-10-01

    This report describes the limited field investigation work done to address issues and answer unresolved questions regarding a collection of potential contaminant sources at Eielson Air Force Base (AFB), near Fairbanks, Alaska. These sources were listed in the Eielson AFB Federal Facility Agreement supporting the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) cleanup of the base. The limited field investigation began in 1993 to resolve all remaining technical issues and provide the data and analysis required to evaluate the environmental hazard associated with these sites. The objective of the limited field investigation was to allow the remedial project managers to sort each site into one of three categories: requiring remedial investigation/feasibility study, requiring interim removal action, or requiring no further remedial action.

  7. Experimental Investigation of Pool Boiling Heat Transfer Enhancement in Microgravity in the Presence of Electric Fields

    NASA Technical Reports Server (NTRS)

    Herman, Cila

    1999-01-01

    In boiling high heat fluxes are possible driven by relatively small temperature differences, which make its use increasingly attractive in aerospace applications. The objective of the research is to develop ways to overcome specific problems associated with boiling in the low gravity environment by substituting the buoyancy force with the electric force to enhance bubble removal from the heated surface. Previous studies indicate that in terrestrial applications nucleate boiling heat transfer can be increased by a factor of 50, as compared to values obtained for the same system without electric fields. The goal of our research is to experimentally explore the mechanisms responsible for EHD heat transfer enhancement in boiling in low gravity conditions, by visualizing the temperature distributions in the vicinity of the heated surface and around the bubble during boiling using real-time holographic interferometry (HI) combined with high-speed cinematography. In the first phase of the project the influence of the electric field on a single bubble is investigated. Pool boiling is simulated by injecting a single bubble through a nozzle into the subcooled liquid or into the thermal boundary layer developed along the flat heater surface. Since the exact location of bubble formation is known, the optical equipment can be aligned and focused accurately, which is an essential requirement for precision measurements of bubble shape, size and deformation, as well as the visualization of temperature fields by HI. The size of the bubble and the frequency of bubble departure can be controlled by suitable selection of nozzle diameter and mass flow rate of vapor. In this approach effects due to the presence of the electric field can be separated from effects caused by the temperature gradients in the thermal boundary layer. The influence of the thermal boundary layer can be investigated after activating the heater at a later stage of the research. For the visualization experiments a

  8. Investigation into the Horizontal Spatial Variability of Dew at Field-Scale

    NASA Astrophysics Data System (ADS)

    Rowlandson, T. L.; Hornbuckle, B. K.; Patton, J.; Russell, E.; Seier, K.; Spoth, K.

    2009-12-01

    The occurrence of free moisture on a crop canopy, whether in the form of intercepted precipitation or dew, has implications for both plant disease development and sensing of soil moisture by microwave remote sensing. In agriculture, the duration of leaf wetness can impact disease development, and with microwave remote sensing, free water on the canopy can influence the detection of soil moisture by increasing or decreasing the measured brightness temperature, depending on the canopy being investigated. Research has been conducted on the variability of dew vertically within a crop canopy; however the horizontal spatial variability of dew at the field scale had not yet been examined. We conducted a study in a maize field during the growing season of 2009 to investigate variations in dew duration and amount at 4 locations in a 1km2 with varying topography and soil characteristics. At each of the four sites, two leaf wetness sensors were installed at both 1/3- and 2/3-canopy height, providing insight into variations in dew duration between the four locations. Above canopy temperature and relative humidity were measured, in addition to in-canopy temperature and relative humidity, measured at half-canopy height. Soil moisture was measured continuously at each of the four locations. Physical samples were taken 11 times during the months of July and August, 2009. Sampling began at sunrise, and was conducted 3 times at each measurement location at both 1/3- and 2/3-canopy height. In addition to samples taken at sunrise, on three occasions, samples were taken at sunset, 11pm and 3am in order to monitor the progression of dew development. A sample at three of the locations occurred at the end of August to determine how dew varies at each location by taking simultaneous measurements. Leaf area index (LAI) was measured throughout the growing season at 1/3- and 2/3-canopy height at each measurement location. This information was utilized to investigate how dew measurements taken

  9. Ballpoint pen ingestion in a 2-year-old child.

    PubMed

    Rameau, Anaïs; Anand, Sumeet M; Nguyen, Lily H

    2011-07-01

    A 2-year-old girl ingested a ballpoint pen, which was found on chest x-ray to have lodged in the lower esophagus and stomach. The pen, which measured nearly 15 cm in length, was removed via rigid esophagoscopy without complication. To the best of our knowledge, this is the longest nonflexible foreign body ingested by a young child ever reported in the English-language literature. We describe the presentation of this case and the current guidelines for safety as enumerated in the Small Parts Regulations established by the U.S. Consumer Product Safety Commission.

  10. NMR investigation of field-induced magnetic order in barium manganese oxide

    NASA Astrophysics Data System (ADS)

    Suh, Steve

    the triangular Mn5+ magnetic lattice of Ba3Mn2O8 coupled with interdimer interaction is predicted to result in incommensurate spin structure when the symmetry axis of Ba3Mn2O8 is aligned parallel to the field. Because of single ion anisotropy of the system, Ba3Mn 2O8 has phase diagram that depends on its alignment with respect to the external field[5]. This means that the microscopic spin structure is different depending on whether the material's symmetry axis is aligned parallel or perpendicular to the field. Also, since we are dealing with S = 1, we have potential to investigate spin-gap closure due to singlet and triplet states as well as triplet and quintet states if we are able to access high enough fields (15T to 30T). Measurements at National High Magnetic Field Laboratory (NHMFL), gives us a superficial taste of what it is like to be in the phase created by triplet and quintet gap closure. The temperature range allowed by the Oxford dilution refrigerator system at Brown Lab, UCLA is from 1K down to 30mK. The magnetic field range allowed by the superconducting magnet at Brown Lab, UCLA is from 0T up to 12T. This combination of temperature and field range allows us to investigate the first quantum critical point (Hc1) in detail with various NMR measurements. Normal state frequency shift as a function of temperature near Hc1 reveals behavior consistent with dilute hardcore bose gas. Analysis of the lineshapes of NMR spectra going into spin order BEC phase as a function of field, we directly observe incommensurate nature of spin order and deduce development of order parameter consistent with mean-field theory. Finally, we verify that the language of dilute 3D Bosons also applies to Ba3Mn2O8 through T1 measurements. From critical behavior inferred in T1 measurements, we complete phase boundary diagram at low temperatures and apply general concept of softening in Goldstone mode near Hc1 to describe our T 1 dependence as a function of temperature.

  11. Investigation of an Optimum Detection Scheme for a Star-Field Mapping System

    NASA Technical Reports Server (NTRS)

    Aldridge, M. D.; Credeur, L.

    1970-01-01

    An investigation was made to determine the optimum detection scheme for a star-field mapping system that uses coded detection resulting from starlight shining through specially arranged multiple slits of a reticle. The computer solution of equations derived from a theoretical model showed that the greatest probability of detection for a given star and background intensity occurred with the use of a single transparent slit. However, use of multiple slits improved the system's ability to reject the detection of undesirable lower intensity stars, but only by decreasing the probability of detection for lower intensity stars to be mapped. Also, it was found that the coding arrangement affected the root-mean-square star-position error and that detection is possible with error in the system's detected spin rate, though at a reduced probability.

  12. Numerical Investigation of the Formation and Detachment of Droplets from Pores in a Shear Flow Field

    NASA Astrophysics Data System (ADS)

    Feigl, Kathleen; Tanner, Franz X.; Windhab, Erich J.

    2010-09-01

    The formation and detachment behavior of droplets from a pore opening into a simple shear field within a channel gap is investigated using numerical simulations. The mathematical model consists of the governing equations for an incompressible two-phase flow problem with a moving contact line. These equations are numerically solved using the volume-of-fluid method implemented in the open source software OpenFOAM. A parameter study was performed to determine the effect of relevant dimensionless parameters on the formation and detachment behavior of the droplets. These dimensionless parameters involve the pore size, pore flow rate, gap shear rate, interfacial tension, and the viscosity and density of the two fluid phases. For the parameter range considered in this study, different degrees of jetting behavior were observed. Also, the sizes of the detached droplets were seen to decrease as the gap shear rate increased, and increase with the pore flow rate, with the gap shear rate having a larger effect.

  13. LOSA-MS lidar for investigation of aerosol fields in the troposphere

    NASA Astrophysics Data System (ADS)

    Bairashin, G. S.; Balin, Yurii S.; Ershov, Arkadii D.; Kokhanenko, Grigorii P.; Penner, I. E.

    2005-07-01

    The LOSA-MS combined small-sized single-wavelength backscatter lidar is described whose operation is based on the effects of Raman and elastic scattering. To extend the range of sounding, lidar returns are registered simultaneously in analog and photon counting regimes. A photodetector system for wavelength and polarization selection of lidar signals is described. The basic physical principles of laser sounding and methods of solving the lidar equation to retrieve information on the optical-physical state of examined objects are presented. Examples of using the LOSA-MS lidar for monitoring of spatiotemporal distribution of aerosol pollutants above an industrial center are given together with examples of investigation of the aerosol field structure under background atmospheric conditions.

  14. Qualitative investigation of fresh human scalp hair with full-field optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Choi, Woo June; Pi, Long-Quan; Min, Gihyeon; Lee, Won-Soo; Lee, Byeong Ha

    2012-03-01

    We have investigated depth-resolved cellular structures of unmodified fresh human scalp hairs with ultrahigh-resolution full-field optical coherence tomography (FF-OCT). The Linnik-type white light interference microscope has been home-implemented to observe the micro-internal layers of human hairs in their natural environment. In hair shafts, FF-OCT has qualitatively revealed the cellular hair compartments of cuticle and cortex layers involved in keratin filaments and melanin granules. No significant difference between black and white hair shafts was observed except for absence of only the melanin granules in the white hair, reflecting that the density of the melanin granules directly affects the hair color. Anatomical description of plucked hair bulbs was also obtained with the FF-OCT in three-dimensions. We expect this approach will be useful for evaluating cellular alteration of natural hairs on cosmetic assessment or diagnosis of hair diseases.

  15. Remedial Investigation Work Plan for J-Field, Aberdeen Proving Ground, Maryland

    SciTech Connect

    Benioff, P.; Biang, R.; Dolak, D.; Dunn, C.; Haffenden, R.; Martino, L.; Patton, T.; Wang, Y.; Yuen, C.

    1995-03-01

    The purpose of an RI/FS is to characterize the nature and extent of the risks posed by contaminants present at a site and to develop and evaluate options for remedial actions. The overall objective of the RI is to provide a comprehensive evaluation of site conditions, types and quantities of contaminants present, release mechanisms and migration pathways, target populations, and risks to human health and the environment. The information developed during the RI provides the basis for the design and implementation of remedial actions during the FS. The purpose of this RI Work Plan is to define the tasks that will direct the remedial investigation of the J-Field site at APG.

  16. Small estuarine fishes feed on large trematode cercariae: Lab and field investigations

    USGS Publications Warehouse

    Kaplan, A.T.; Rebhal, S.; Lafferty, K.D.; Kuris, A.M.

    2009-01-01

    In aquatic ecosystems, dense populations of snails can shed millions of digenean trematode cercariae every day. These short-lived, free-living larvae are rich in energy and present a potential resource for consumers. We investigated whether estuarine fishes eat cercariae shed by trematodes of the estuarine snail Cerithidea californica. In aquaria we presented cercariae from 10 native trematode species to 6 species of native estuarine fishes. Many of these fishes readily engorged on cercariae. To determine if fishes ate cercariae in the field, we collected the most common fish species, Fundulus parvipinnis (California killifish), from shallow water on rising tides when snails shed cercariae. Of 61 killifish, 3 had recognizable cercariae in their gut. Because cercariae are common in this estuary, they could be frequent sources of energy for small fishes. In turn, predation on cercariae by fishes (and other predators) could also reduce the transmission success of trematodes. ?? 2009 American Society of Parasitologists.

  17. Controlled doping of silicon nanocrystals investigated by solution-processed field effect transistors.

    PubMed

    Gresback, Ryan; Kramer, Nicolaas J; Ding, Yi; Chen, Ting; Kortshagen, Uwe R; Nozaki, Tomohiro

    2014-06-24

    The doping of semiconductor nanocrystals (NCs), which is vital for the optimization of NC-based devices, remains a significant challenge. While gas-phase plasma approaches have been successful in incorporating dopant atoms into NCs, little is known about their electronic activation. Here, we investigate the electronic properties of doped silicon NC thin films cast from solution by field effect transistor analysis. We find that, analogous to bulk silicon, boron and phosphorus electronically dope Si NC thin films; however, the dopant activation efficiency is only ∼10(-2)-10(-4). We also show that surface doping of Si NCs is an effective way to alter the carrier concentrations in Si NC films.

  18. Investigation of dyed human hair fibres using apertureless near-field scanning optical microscopy.

    PubMed

    Formanek, F; DE Wilde, Y; Luengo, G S; Querleux, B

    2006-11-01

    We present the first studies of dyed human hair fibres performed with an apertureless scanning near-field optical microscope. Samples consisted of 5-microm-thick cross-sections, the hair fibres being bleached and then dyed before being cut. Hair dyed with two molecular probes diffusing deep inside the fibre or mainly spreading at its periphery were investigated at a wavelength of 655 nm. An optical resolution of about 50 nm was achieved, well below the diffraction limit; the images exhibited different optical contrasts in the cuticle region, depending on the nature of the dye. Our results suggest that the dye that remains confined at the hair periphery is mainly located at its surface and in the endocuticle.

  19. Metabolic Investigation in Gluconacetobacter xylinus and Its Bacterial Cellulose Production under a Direct Current Electric Field

    PubMed Central

    Liu, Miao; Zhong, Cheng; Zhang, Yu Ming; Xu, Ze Ming; Qiao, Chang Sheng; Jia, Shi Ru

    2016-01-01

    The effects of a direct current (DC) electric field on the growth and metabolism of Gluconacetobacter xylinus were investigated in static culture. When a DC electric field at 10 mA was applied using platinum electrodes to the culture broth, bacterial cellulose (BC) production was promoted in 12 h but was inhibited in the last 12 h as compared to the control (without DC electric field). At the cathode, the presence of the hydrogen generated a strong reductive environment that is beneficial to cell growth. As compared to the control, the activities of glycolysis and tricarboxylic acid cycle, as well as BC productivity were observed to be slightly higher in the first 12 h. However, due to the absence of sufficient oxygen, lactic acid was accumulated from pyruvic acid at 18 h, which was not in favor of BC production. At the anode, DC inhibited cell growth in 6 h when compared to the control. The metabolic activity in G. xylinus was inhibited through the suppression of the tricarboxylic acid cycle and glycolysis. At 18–24 h, cell density was observed to decrease, which might be due to the electrolysis of water that significantly dropped the pH of cultural broth far beyond the optimal range. Meanwhile, metabolites for self-protection were accumulated, for instance proline, glutamic acid, gluconic acid, and fatty acids. Notably, the accumulation of gluconic acid and lactic acid made it a really tough acid stress to cells at the anode and finally led to depression of cell growth. PMID:27014248

  20. Development of Electric Field Investigations for Future Missions in Japan: from Mercury, through Earth, toward Jupiter

    NASA Astrophysics Data System (ADS)

    Kasaba, Yasumasa

    The electric field from DC to several 10s MHz is important for the clarification of global plasma dynamics, energetic processes, and wave-particle interactions in the planetary Magnetospheres by in-situ and remote sensing studies. We have developped the instruments for several missions, i.e., (1) BepiColombo Mercury Mag-netospheric Orbiter (MMO) to Mercury [just in FM development], (2) the small-sized radiation belt mission, ERG (Energization and Radiation in Geospace) [in EM design], (3) the cross-scale formation flight mission, SCOPE [in ceonceptual design], and (4) the future Jovian mission, EJSM, including JAXA Jupiter Magnetospheric Orbiter (JMO) and other elementss [in con-ceptual design]. Those will prevail the universal plasma mechanism and processes in the space laboratory. The common purposes of electric field, plasma waves, and radio waves observa-tion in those missions are: (a) Examination of the theories of high-energy particle acceleration by plasma waves, (b) identification of the origin of electric fields in the magnetosphere asso-ciated with cross-scale coupling processes, (c) diagnosis of plasma density, temperature and composition, and (d) investigation of wave-particle interaction and mode conversion processes. In order to achieve those objectives, the instrument including rigid antenna, wire antenna, and integrated receiver systems are now in development. Some of them were already used on the sounding rocket experiments (S310-23 launched by ISAS/JAXA) in 2007, and will also be used soon. As the applications of those development, we also try to adopt them to the space interferometer and the radar sounder. In this paper, we will summarize the current plan and efforts for those future activities.

  1. PIXELS: Using field-based learning to investigate students' concepts of pixels and sense of scale

    NASA Astrophysics Data System (ADS)

    Pope, A.; Tinigin, L.; Petcovic, H. L.; Ormand, C. J.; LaDue, N.

    2015-12-01

    Empirical work over the past decade supports the notion that a high level of spatial thinking skill is critical to success in the geosciences. Spatial thinking incorporates a host of sub-skills such as mentally rotating an object, imagining the inside of a 3D object based on outside patterns, unfolding a landscape, and disembedding critical patterns from background noise. In this study, we focus on sense of scale, which refers to how an individual quantified space, and is thought to develop through kinesthetic experiences. Remote sensing data are increasingly being used for wide-reaching and high impact research. A sense of scale is critical to many areas of the geosciences, including understanding and interpreting remotely sensed imagery. In this exploratory study, students (N=17) attending the Juneau Icefield Research Program participated in a 3-hour exercise designed to study how a field-based activity might impact their sense of scale and their conceptions of pixels in remotely sensed imagery. Prior to the activity, students had an introductory remote sensing lecture and completed the Sense of Scale inventory. Students walked and/or skied the perimeter of several pixel types, including a 1 m square (representing a WorldView sensor's pixel), a 30 m square (a Landsat pixel) and a 500 m square (a MODIS pixel). The group took reflectance measurements using a field radiometer as they physically traced out the pixel. The exercise was repeated in two different areas, one with homogenous reflectance, and another with heterogeneous reflectance. After the exercise, students again completed the Sense of Scale instrument and a demographic survey. This presentation will share the effects and efficacy of the field-based intervention to teach remote sensing concepts and to investigate potential relationships between students' concepts of pixels and sense of scale.

  2. Numerical investigation of the dynamics of Janus magnetic particles in a rotating magnetic field

    NASA Astrophysics Data System (ADS)

    Kim, Hui Eun; Kim, Kyoungbeom; Ma, Tae Yeong; Kang, Tae Gon

    2017-02-01

    We investigated the rotational dynamics of Janus magnetic particles suspended in a viscous liquid, in the presence of an externally applied rotating magnetic field. A previously developed two-dimensional direct simulation method, based on the finite element method and a fictitious domain method, is employed to solve the magnetic particulate flow. As for the magnetic problem, the two Maxwell equations are converted to a differential equation using the magnetic potential. The magnetic forces acting on the particles are treated by a Maxwell stress tensor formulation, enabling us to consider the magnetic interactions among the particles without any approximation. The dynamics of a single particle in the rotating field is studied to elucidate the effect of the Mason number and the magnetic susceptibility on the particle motions. Then, we extended our interest to a two-particle problem, focusing on the effect of the initial configuration of the particles on the particle motions. In three-particle interaction problems, the particle dynamics and the fluid flow induced by the particle motions are significantly affected by the particle configuration and the orientation of each particle.

  3. Investigation of Acoustic Fields for the Cassini Spacecraft: Reverberant Versus Launch Environments

    NASA Technical Reports Server (NTRS)

    Hughes, William O.; McNelis, Anne M.; Himelblau, Harry

    2000-01-01

    The characterization and understanding of the acoustic field within a launch vehicle's payload fairing (PLF) is critical to the qualification of a spacecraft and ultimately to the success of its mission. Acoustic measurements taken recently for the Cassini mission have allowed unique opportunities to advance the aerospace industry's knowledge in this field. Prior to its launch, the expected liftoff acoustic environment of the spacecraft was investigated in a full-scale acoustic test of a Titan IV PLF and Cassini simulator in a reverberant test chamber. A major goal of this acoustic ground test was to quantify and verify the noise reduction performance of special barrier blankets that were designed especially to reduce the Cassirii acoustic environment. This paper will describe both the ground test and flight measurements, and compare the Cassini acoustic environment measured during launch with that measured earlier in the ground test. Special emphasis will be given to the noise reduction performance of the barrier blankets and to the acoustic coherence measured within the PLF.

  4. Field investigations of the interaction between debris flows and forest vegetation in two Alpine fans

    NASA Astrophysics Data System (ADS)

    Michelini, Tamara; Bettella, Francesco; D'Agostino, Vincenzo

    2017-02-01

    A key objective in debris-flow hazard mitigation is the reduction of the potential depositional area in the fan. From this point of view, forested areas are able to provide a protective function hindering the flow motion and promoting the surge deposition. Despite extensive research on Alpine forests and their protective functions, relatively few studies in the literature have quantitatively focused on the relationship between debris-flow depositional features and vegetation. In light of the above, our research investigates how vegetation characteristics in the fan area interact with debris-flow deposition. Field investigations were carried out in two Alpine fans where debris-flow events occurred in the summer of 2012. By recording the characteristics of 1567 involved trees and the associated deposit thicknesses, this paper provides a data set that contributes to the improvement of the knowledge of these interaction processes. The integration of literature findings and the analysis of the collected dataset adds insights into the relationships between tree characteristics and the dynamics of debris flow during the runout path. The main results prove the capacity of the forest of uniformly promoting flow-energy dissipation, presence of high species diversity in debris-flow deposits when comparing disturbed and undisturbed forest stands, tree mortality largely affecting small diameters < 10 cm in the upper/medium part of the cone, and deposit thicknesses depending on the trunk diameter only if the debris-flow regime was collisional. Based on the field results and their analysis, some criteria for the management of protection forests in alluvial fans are suggested.

  5. Investigation on critical breakdown electric field of hot carbon dioxide for gas circuit breaker applications

    NASA Astrophysics Data System (ADS)

    Sun, Hao; Rong, Mingzhe; Wu, Yi; Chen, Zhexin; Yang, Fei; Murphy, Anthony B.; Zhang, Hantian

    2015-02-01

    Sulfur hexafluoride (SF6) gas is widely used in high-voltage circuit breakers, but due to its high global warming potential, substitutes are being sought. CO2 has been investigated as a candidate based on its arc interruption performance. The hot gas in the circuit breaker after current zero, with a complicated species composition caused by the dissociation and many other reactions, will lead to the electrical breakdown, which is one of the major concerns in assessing the arc interruption performance. Despite this, little research has been reported on the dielectric strength of hot CO2. In this paper, the dielectric properties of hot CO2 related to the dielectric recovery phase of the circuit breaker were investigated in the temperature range from 300 to 4000 K and in the pressure range from 0.01 to 1.0 MPa. Under the assumptions of local thermodynamic equilibrium (LTE) and local chemical equilibrium (LCE), the equilibrium compositions of hot CO2 were obtained based on Gibbs free energy minimization. The cross sections for interactions between electrons and the species are presented. The critical reduced electric field strength of CO2 was determined by balancing electron generation and loss. These were evaluated using the electron energy distribution function (EEDF) derived from the two-term Boltzmann transport equation. The result indicates that unlike SF6 or air, in hot CO2 the reduced critical electric field strength does not change monotonically with increasing heavy-particle temperature from 300 to 4000 K. CO2 has a superior dielectric strength to pure SF6 above 2500 K at 0.5 MPa, which means it has the potential to improve the interruption performance of the circuit breakers, while reducing the global warming effect. Good agreement was found with published experimental results and calculations for CO2 at room temperature, and with previous calculations for hot CO2.

  6. Limited field investigation report for the 100-HR-3 operable unit

    SciTech Connect

    Not Available

    1994-09-01

    This limited field investigation (LFI) was conducted to assess the applicability of interim remedial measures (IRM) for reducing human health and environmental risks within the 100-HR-3 Groundwater Operable Unit. The 100-HR-3 Operable Unit is comprised of three subareas; the 100 D Area, the 100 H Area and those portions of the 600 Area between the two reactor areas. The operable unit is one of seven operable units associated with the 100 D and H Areas. Operable units 100-DR-1, 100-DR-2, 100-DR-3, 100-HR-1, 100-HR-2 and 100-IU-4 address contaminant sources while 100-HR-3 addresses contamination present in the underlying groundwater. The primary method of field investigation used during this LFI was the installation and sampling of monitoring wells. Samples were collected from the groundwater and soils, and submitted for laboratory analysis. Boreholes were surveyed for radiological contamination using downhole geophysical techniques to further delineate the locations and levels of contaminants. All samples were screened to ascertain the presence of volatile organic compounds and radionuclides. Analytical data were subjected to validation; all round one, two and three and a minimum of 10% of round four data associated with the LFI were validated. A screening method was used to identify contaminants of potential concern (COPC). This screening method eliminated from further consideration, constituents that were below background. Constituents which are considered non-toxic to humans were eliminated from the human health evaluation. Data consistency and blank contamination were also evaluated in the screening process. These COPC were then evaluated further in the qualitative risk assessment (QRA). A human health QRA was performed using conservative (maximum equilibrated contaminant levels from the LFI) analyses.

  7. Coordination of Lip Muscle Activity by 2-Year-Old Children During Speech and Nonspeech Tasks

    PubMed Central

    Ruark, Jacki L.; Moore, Christopher A.

    2014-01-01

    This investigation was designed to quantify the coordinative organization of lip muscle activity of 2-year-old children during speech and nonspeech behaviors. Electromyographic (EMG) recordings of right upper and lower lip activity of seven 2-year-old children were obtained during productions of chewing, syllable repetition, lip protrusion, and speech (repeated two-word utterances) tasks. Task comparisons revealed that the coordinative organization of upper and lower lip activity is task specific; different coordinative strategies are employed for different tasks. Lip protrusion and syllable repetition tasks yielded strong coupling of upper and lower lip activity. Lip rounding (sentences containing the lip-rounding vowel /u/) and “nonlabial” speech tasks (sentences free of bilabials and lip-rounding vowels) resulted in low coupling of upper and lower lip activity. Moderate levels of coupling of upper and lower lip activity were evident for chewing and bilabial speech tasks (sentences loaded with bilabial plosion). This finding, that the coordinative elements of the perioral system of 2-year-olds are task specific, extends the results of previous studies of adults and children, where task-specific coordinative strategies were employed by the mandibular and perioral systems (Moore, 1993; Moore & Ruark, 1996; Moore, Smith, & Ringel, 1988; Wohlert & Goffman, 1994). The task-dependent coordination of the perioral system of 2-year-olds supports the notion that developing speech and earlier developing oromotor behaviors (i.e., sucking, chewing) are mediated by different control mechanisms. PMID:9430757

  8. Data use investigation for the magnetic field satellite (MAGSAT) mission: Geomagnetic field forecasting and fluid dynamics of the core

    NASA Technical Reports Server (NTRS)

    Benton, E. R. (Principal Investigator)

    1982-01-01

    MAGSAT data were used to construct a variety of spherical harmonic models of the main geomagnetic field emanating from Earth's liquid core at poch 1980. These models were used to: (1) accurately determine the radius of Earth's core by a magnetic method, (2) calculate estimates, of the long-term ange of variation of geomagnetic Gauss coefficients; (3) establish a preferred truncation level for current spherical harmonic models of the main geomagnetic field from the core; (4) evaluate a method for taking account of electrical conduction in the mantle when the magnetic field is downward continued to the core-mantle boundary; and (5) establish that upwelling and downwelling of fluid motion at the top of the core is probably detectable, observationally. A fluid dynamics forecast model was not produced because of insufficient data.

  9. An experimental investigation of velocity fields in divergent glottal models of the human vocal tract

    NASA Astrophysics Data System (ADS)

    Erath, Byron D.; Plesniak, Michael W.

    2005-09-01

    In speech, sound production arises from fluid-structure interactions within the larynx as well as viscous flow phenomena that is most likely to occur during the divergent orientation of the vocal folds. Of particular interest are the flow mechanisms that influence the location of flow separation points on the vocal folds walls. Physiologically scaled pulsatile flow fields in 7.5 times real size static divergent glottal models were investigated. Three divergence angles were investigated using phase-averaged particle image velocimetry (PIV). The pulsatile glottal jet exhibited a bi-modal stability toward both glottal walls, although there was a significant amount of variance in the angle the jet deflected from the midline. The attachment of the Coanda effect to the glottal model walls occurred when the pulsatile velocity was a maximum, and the acceleration of the waveform was zero. The location of the separation and reattachment points of the flow from the glottal models was a function of the velocity waveform and divergence angle. Acoustic analogies show that a dipole sound source contribution arising from the fluid interaction (Coanda jet) with the vocal fold walls is expected. [Work funded by NIH Grant RO1 DC03577.

  10. Investigation of the dimensionality of charge transport in organic field effect transistors

    NASA Astrophysics Data System (ADS)

    Abdalla, Hassan; Fabiano, Simone; Kemerink, Martijn

    2017-02-01

    Ever since the first experimental investigations of organic field effect transistors (OFETs) the dimensionality of charge transport has alternately been described as two dimensional (2D) and three dimensional (3D). More recently, researchers have turned to an analytical analysis of the temperature-dependent transfer characteristics to classify the dimensionality as either 2D or 3D as well as to determine the disorder of the system, thereby greatly simplifying dimensionality investigations. We applied said analytical analysis to the experimental results of our OFETs comprising molecularly well-defined polymeric layers as the active material as well as to results obtained from kinetic Monte Carlo simulations and found that it was not able to correctly distinguish between 2D and 3D transports or give meaningful values for the disorder and should only be used for quasiquantitative and comparative analysis. We conclude to show that the dimensionality of charge transport in OFETs is a function of the interplay between transistor physics and morphology of the organic material.

  11. Field Investigation of Natural Attenuation of a Petroleum Hydrocarbon Contaminated Aquifer, Gyeonggi Province, Korea

    NASA Astrophysics Data System (ADS)

    Yang, J.; Lee, K.; Bae, G.

    2004-12-01

    In remediation of a petroleum hydrocarbon contaminated aquifer, natural attenuation may be significant as a remedial alternative. Therefore, natural attenuation should be investigated in the field in order to effectively design and evaluate the remediation strategy at the contaminated site. This study focused on evaluating the natural attenuation for benzene, toluene, ethylbenzene, and xylene (BTEX) at a contaminated site in South Korea. At the study site, the aquifer is composed of a high permeable gravel layer and relatively low permeable sandy-silt layers. Groundwater level vertically fluctuated between 1m and 2m throughout the year (April, 2003~June, 2004) and showed direct response to rainfall events. Chemical analyses of sampled groundwater were performed to investigate the concentrations of various chemical species which are associated with the natural attenuation processes. To evaluate the degree of the biodegradation, the expressed biodegradation capacity (EBC) analysis was done using aerobic respiration, nitrate reduction, manganese reduction, ferric iron reduction, and sulfate reduction as an indicator. High EBC value of sulfate indicate that anaerobic biodegradation by sulfate reduction was a dominant process of mineralization of BTEX at this site. The EBC values decrease sensitively when heavy rainfall occurs due to the dilution and inflow of electron acceptors through a gravel layer. The first-order biodegradation rates of BTEX were estimated by means of the Buscheck and Alcantar method (1995). Results show that the natural attenuation rate of benzene was the highest among the BTEX.

  12. Remediation of dissolved BTEX through surface application: A prototype field investigation

    SciTech Connect

    O`Leary, K.E.; Barker, J.F.; Gillham, R.W.

    1995-12-31

    The feasibility of surface application for remediating monoaromatic hydrocarbons (benzene, toluene, ethylbenzene, and xylenes--termed BTEX as a group) dissolved in ground water under field conditions was investigated at a sit within Canadian Forces Base, Borden, Ontario. The surface area was 25 m{sup 2} and underlain by 3 to 3.5 m of unsaturated sandy soil. For periods of at least 216 hours, between 43 and 72 cm/d of water containing BTEX at concentrations that averaged between 8 and 11 mg/L were continuously applied by drip irrigation. Nitrogen was added to the soil as a nutrient for the final third of the investigation. Before the applied water reached the water table, BTEX mass losses ranged from 65 to essentially 100 percent. Less than 6 percent of the BTEX mass losses could be attributed to volatilization from the unsaturated soil. The remaining BTEX mass losses were attributed to biodegradation, mostly in the top 50 cm of the soil, which contained more organic nitrogen and organic carbon than the deeper soil. Biodegradation rates increased with applied concentration, nitrogen addition, and exposure to BTEX. Benzene concentrations in ground water attained compliance with Canadian and American drinking water standards only after nitrogen application.

  13. An Investigation on the Effect of Extremely Low Frequency Pulsed Electromagnetic Fields on Human Electrocardiograms (ECGs)

    PubMed Central

    Fang, Qiang; Mahmoud, Seedahmed S.; Yan, Jiayong; Li, Hui

    2016-01-01

    For this investigation, we studied the effects of extremely low frequency pulse electromagnetic fields (ELF-PEMF) on the human cardiac signal. Electrocardiograms (ECGs) of 22 healthy volunteers before and after a short duration of ELF-PEMF exposure were recorded. The experiment was conducted under single-blind conditions. The root mean square (RMS) value of the recorded data was considered as comparison criteria. We also measured and analysed four important ECG time intervals before and after ELF-PEMF exposure. Results revealed that the RMS value of the ECG recordings from 18 participants (81.8% of the total participants) increased with a mean value of 3.72%. The increase in ECG voltage levels was then verified by a second experimental protocol with a control exposure. In addition to this, we used hyperbolic T-distributions (HTD) in the analysis of ECG signals to verify the change in the RR interval. It was found that there were small shifts in the frequency-domain signal before and after EMF exposure. This shift has an influence on all frequency components of the ECG signals, as all spectrums were shifted. It is shown from this investigation that a short time exposure to ELF-PEMF can affect the properties of ECG signals. Further study is needed to consolidate this finding and discover more on the biological effects of ELF-PEMF on human physiological processes. PMID:27886102

  14. Field investigation of a vibration monitoring wireless sensor network on a huge cantilever structure

    NASA Astrophysics Data System (ADS)

    Zhou, H. F.; Liu, J. L.; Ni, Y. Q.; Zhu, D. P.

    2011-04-01

    To advance wireless structural monitoring systems mature into a reliable substitute to wired structural monitoring systems, efforts should be paid to investigate their in-field performance on real civil structures, especially complex mega structures. This study carries out an investigation into a vibration monitoring wireless sensor network (WSN) for modal identification of a huge cantilever structure. The testbed under study is the New Headquarters of Shenzhen Stock Exchange (NHSSE). One outstanding feature of NHSSE is its huge floating platform, which is a steel truss structure with an overall plan dimension of 98x162 m and a total height of 24 m. It overhangs from the main tower 36 m along the long axis and 22 m along the short axis at a height of 36 m above the ground, making it the largest cantilever structure in the world. Recognizing the uniqueness of this floating platform, the performance of the WSN for ambient vibration measurement of this structure is examined. A preliminary two-point simultaneous acceleration measurement using the WSN is reported in this paper. The preliminary study demonstrates that the WSN is capable of measuring the ambient vibration and identifying the modal properties of a huge cantilever structure.

  15. Limited field investigation report for the 100-KR-4 Operable Unit

    SciTech Connect

    Not Available

    1994-07-01

    This limited field investigation (LFI) was conducted to optimize the use of interim remedial measures (IRM) for expediting clean up while maintaining a technically sound and cost-effective program. The 100-KR-4 Operable Unit is one of four operable units associated with the 100 K Area. Operable units KR-1, KR-2 and KR-3 address contaminant sources while 100-KR-4 addresses contamination present in the underlying groundwater. The IRM decision process for groundwater operable units is based on three aspects: (1) Is the concentration greater than Hanford background? (2) Does the concentration present a medium or high human-health risk? (3) Does the concentration exceed an ecologically based applicable, relevant and appropriate requirements (ARAR) or present an environmental hazard quotient > I? The primary methods of investigation used during this LFI were the installation of monitoring wells and sampling of groundwater. The samples collected from the groundwater and soils were submitted for laboratory analysis. Boreholes were surveyed for radiological contamination using downhole geophysical techniques to further delineate the location and degree of contamination. All soil samples were screened to ascertain the presence of volatile organic compounds and radionuclides. Analytical data were subjected to validation; all first round and a minimum of 10% of subsequent round data were validated.

  16. A preliminary investigation: the impact of microscopic condenser on depth of field in cytogenetic imaging

    NASA Astrophysics Data System (ADS)

    Ren, Liqiang; Qiu, Yuchen; Li, Zheng; Li, Yuhua; Zheng, Bin; Li, Shibo; Chen, Wei R.; Liu, Hong

    2013-02-01

    As one of the important components of optical microscopes, the condenser has a considerable impact on system performance, especially on the depth of field (DOF). DOF is a critical technical feature in cytogenetic imaging that may affect the efficiency and accuracy of clinical diagnosis. The purpose of this study is to investigate the influence of microscopic condenser on DOF using a prototype of transmitted optical microscope, based on objective and subjective evaluations. After the description of the relationship between condenser and objective lens and the theoretical analysis of the condenser impact on system numerical aperture and DOF, a standard resolution pattern and several cytogenetic samples are adopted to assess the condenser impact on DOF, respectively. The experimental results of these objective and subjective evaluations are in agreement with the theoretical analysis and show that, under the specific intermediate range of condenser numerical aperture ( NAcond ), the DOF value decreases with the increase of NAcond . Although the above qualitative results are obtained under the experimental conditions with a specific prototype system, the methods presented in this preliminary investigation could offer useful guidelines for optimizing operational parameters in cytogenetic imaging.

  17. Comparing field investigations with laboratory models to predict landfill leachate emissions

    SciTech Connect

    Fellner, Johann; Brunner, Paul H.

    2009-06-15

    Investigations into laboratory reactors and landfills are used for simulating and predicting emissions from municipal solid waste landfills. We examined water flow and solute transport through the same waste body for different volumetric scales (laboratory experiment: 0.08 m{sup 3}, landfill: 80,000 m{sup 3}), and assessed the differences in water flow and leachate emissions of chloride, total organic carbon and Kjeldahl nitrogen. The results indicate that, due to preferential pathways, the flow of water in field-scale landfills is less uniform than in laboratory reactors. Based on tracer experiments, it can be discerned that in laboratory-scale experiments around 40% of pore water participates in advective solute transport, whereas this fraction amounts to less than 0.2% in the investigated full-scale landfill. Consequences of the difference in water flow and moisture distribution are: (1) leachate emissions from full-scale landfills decrease faster than predicted by laboratory experiments, and (2) the stock of materials remaining in the landfill body, and thus the long-term emission potential, is likely to be underestimated by laboratory landfill simulations.

  18. Neonates with extra-renal pelvis: the first 2 years.

    PubMed

    Katzir, Ze'ev; Witzling, Michaela; Nikolov, Gallina; Gvirtz, Gabriela; Arbel, Eliana; Kohelet, David; Boaz, Mona; Smetana, Shmuel; Lorberboym, Mordechai

    2005-06-01

    Extra-renal pelvis (ERpel) is a common ultrasonographic finding among neonates who have undergone recurrent ultrasound examinations for a better definition of prenatal renal pelvic dilatation. This study tries to determine whether or not ERpel has important prognostic implications. Seventy-nine neonates (17 female) were examined. All had a diagnosis of prenatal renal pelvis dilatation, which was shown by postnatal ultrasound to be ERpel. Sixty ERpel neonates were examined 1.5 months to 2.5 months after the ultrasound (US) diagnosis by both Tc-99m diethylene triamine penta-acetic acid (DPTA) dynamic renal scanning and (99m)Tc-pertechnetate direct cystography. Clinical assessment, urine cultures and renal ultrasound follow-up were maintained for 2 years. The proportion of urinary tract infections (UTIs) in patients with ERpel was compared with that of the total neonatal and infantile population with normal US scans in the region of our hospital. Associated minor congenital malformations were found in 12 of 79 neonates (15.2%). Four had a family history of ERpel. Among 60 neonates who underwent renal scanning, 36 (60%) were found to have urinary retention in the collecting system. Another nine (15%) had vesico-ureteral (VU) reflux, of which seven had urinary retention. Fifteen (25%) showed normal isotope imaging. Urinary tract infection was diagnosed in 16 ERpel neonates in whom only one exhibited VU reflux (grade 2). The incidence of neonatal UTI in the ERpel group was more than that of either neonatal or infantile UTI in those with normal US scans in the local population (20.2% vs 1.2% and 4.3%, respectively). Fifty-three infants completed a 2-year follow-up. Repeat renal ultrasonography indicated that one infant (1.8%) had developed bilateral hydronephrosis, 12 (22.6%) had unchanged findings, 18 (40%) showed an improvement (decrease of ERpel width or resolution in one side) and, in 22 (41.5%) infants, the condition had resolved. No clinical or kidney function

  19. Limited field investigation report for the 100-HR-1 Operable Unit

    SciTech Connect

    Not Available

    1994-08-01

    This limited field investigation (LFI) report summarizes the data collection and analysis activities conducted during the 100-HR-1 Source Operable Unit LFI and the associated qualitative risk assessment (QRA) (WHC 1993a), and makes recommendations on the continued candidacy of high-priority sites for interim remedial measures (IRM). The results and recommendations presented in this report are generally independent of future land use scenarios. A LFI Report is required, in accordance with the HPPS, when waste sites are to be considered for IRMs. The LFI is an integral part of the remedial investigation/feasibility study (RI/FS) or Resource Conservation and Recovery Act (RCRA) facility investigation/corrective measures study (RFI/CMS) and process and functions as a focused RI or RFI for selection of IRMs. The purpose of the report is to identify those sites that are recommended to remain as candidates for IRMs, provide a preliminary summary of site characterization studies, refine the conceptual model as needed, identify contaminant- and location-specific applicable or relevant and appropriate requirements (ARA), and provide a qualitative assessment of the risks associated with the sites. This assessment includes consideration of whether contaminant concentrations pose an unacceptable risk that warrants action through IRMs. The 100-HR-1 unit encompasses approximately 100 acres adjacent to the Columbia River shoreline. It contains waste units associated with the original plant facilities constructed to support the H Reactor. The area also contains evaporation basins which received liquid process wastes and nonroutine deposits of chemical wastes from the 300 Area, where fuel elements for the N Reactor were produced.

  20. Investigating microbial transformations of soil organic matter: synthesizing knowledge from disparate fields to guide new experimentation

    NASA Astrophysics Data System (ADS)

    Billings, S. A.; Tiemann, L. K.; Ballantyne, F., IV; Lehmeier, C. A.; Min, K.

    2015-04-01

    Discerning why some soil organic matter (SOM) leaves soil profiles relatively quickly while other compounds, especially at depth, can be retained for decades to millennia is challenging for a multitude of reasons. Simultaneous with soil-specific advances, multiple other disciplines have enhanced their knowledge bases in ways potentially useful for future investigations of SOM decay. In this article, we highlight observations highly relevant for those investigating SOM decay and retention but often emanating from disparate fields and residing in literature seldom cited in SOM research. We focus on recent work in two key areas. First, we turn to experimental approaches using natural and artificial aquatic environments to investigate patterns of microbially mediated OM transformations as environmental conditions change, and highlight how aquatic microbial responses to environmental change can reveal processes likely important to OM decay and retention in soils. Second, we emphasize the importance of establishing intrinsic patterns of decay kinetics for purified substrates commonly found in soils to develop baseline rates. These decay kinetics - which represent the upper limit of the reaction rates - can then be compared to substrate decay kinetics observed in natural samples, which integrate intrinsic decay reaction rates and edaphic factors essential to the site under study but absent in purified systems. That comparison permits the site-specific factors to be parsed from the fundamental decay kinetics, an important advance in our understanding of SOM decay (and thus persistence) in natural systems. We then suggest ways in which empirical observations from aquatic systems and purified substrate-enzyme reaction kinetics can be used to advance recent theoretical efforts in SOM-focused research. Finally, we suggest how the observations in aquatic and purified substrate-enzyme systems could be used to help unravel the puzzles presented by oft-observed patterns of SOM

  1. Investigating short-term exposure to electromagnetic fields on reproductive capacity of invertebrates in the field situation.

    PubMed

    Vijver, Martina G; Bolte, John F B; Evans, Tracy R; Tamis, Wil L M; Peijnenburg, Willie J G M; Musters, C J M; de Snoo, Geert R

    2014-01-01

    Organisms are exposed to electromagnetic fields from the introduction of wireless networks that send information all over the world. In this study we examined the impact of exposure to the fields from mobile phone base stations (GSM 900 MHz) on the reproductive capacity of small, virgin, invertebrates. A field experiment was performed exposing four different invertebrate species at different distances from a radiofrequency electromagnetic fields (RF EMF) transmitter for a 48-h period. The control groups were isolated from EMF exposure by use of Faraday cages. The response variables as measured in the laboratory were fecundity and number of offspring. Results showed that distance was not an adequate proxy to explain dose-response regressions. No significant impact of the exposure matrices, measures of central tendency and temporal variability of EMF, on reproductive endpoints was found. Finding no impact on reproductive capacity does not fully exclude the existence of EMF impact, since mechanistically models hypothesizing non-thermal-induced biological effects from RF exposure are still to be developed. The exposure to RF EMF is ubiquitous and is still increasing rapidly over large areas. We plea for more attention toward the possible impacts of EMF on biodiversity.

  2. [Environmental investigation of ground water contamination at Wright- Patterson Air Force Base, Ohio]. Volume 4, Health and Safety Plan (HSP); Phase 1, Task 4 Field Investigation report: Draft

    SciTech Connect

    Not Available

    1991-10-01

    This Health and Safety Plan (HSP) was developed for the Environmental Investigation of Ground-water Contamination Investigation at Wright-Patterson Air Force Base near Dayton, Ohio, based on the projected scope of work for the Phase 1, Task 4 Field Investigation. The HSP describes hazards that may be encountered during the investigation, assesses the hazards, and indicates what type of personal protective equipment is to be used for each task performed. The HSP also addresses the medical monitoring program, decontamination procedures, air monitoring, training, site control, accident prevention, and emergency response.

  3. A phonological system at 2 years after cochlear implantation

    PubMed Central

    CHIN, STEVEN B.; PISONI, DAVID B.

    2011-01-01

    This report is a description of a developing phonological system as manifested in the productions of a prelingually deafened child approximately 2 years after fitting with a Nucleus 22-Channel Multi-Electrode Cochlear Implant. A probe list consisting of 23 proper nouns familiar to the child was used to elicit samples of her speech; stimulus materials consisted of photographs of those persons (friends and family members) whose names were included in the probe list. Analysis of the child's productions addressed the composition of the phonetic inventory of consonants and vowels and the presence of syllable structure and other phonotactic constraints. Results indicated a rich inventory of speech sound segments (among both consonants and vowels) and a lack of stringent constraints on syllable structure and consonants permitted in specified word positions. A further comparative analysis of correspondences with the ambient language showed a number of patterns that are also common in the speech of children with normal hearing. PMID:22091697

  4. Langerhans cell histiocytosis in children under 2 years of age.

    PubMed

    Rivera-Luna, R; Alter-Molchadsky, N; Cardenas-Cardos, R; Martínez-Guerra, G

    1996-05-01

    This is a retrospective study of 55 children under the age of 2 years diagnosed with Langerhans cell histiocytosis (LCH). They were classified according to age and organ function and dysfunction following Lahey's criteria. The studied population was divided into four groups by age of diagnosis (0-6, 7-12, 13-18, and 19-24 months). Statistical analysis showed no significant difference in outcome between age groups, although the population under 6 months had a 81.3% fatality rate. The presence of organ dysfunction was a major cause of death in all age groups, being statistically significant in outcome (P > 0.005) compared with patients without organ dysfunction. The presence of thrombocytopenia and/or respiratory dysfunction was also highly associated with a fatal outcome. In the surviving population, no second malignancies have been reported. The late secondary effects of therapy include endocrine, orofacial, and osseous pathologies.

  5. Latent rheumatic heart disease: outcomes 2 years after echocardiographic detection.

    PubMed

    Beaton, Andrea; Okello, Emmy; Aliku, Twalib; Lubega, Sulaiman; Lwabi, Peter; Mondo, Charles; McCarter, Robert; Sable, Craig

    2014-10-01

    Screening with portable echocardiography has uncovered a large burden of latent rheumatic heart disease (RHD) among asymptomatic children in endemic regions, the significance of which remains unclear. This study aimed to determine the 2-year outcomes for children with latent RHD diagnosed by echocardiographic screening. Children identified with latent RHD enrolled in a biannual follow-up program. Risk factors for disease persistence and progression were examined. Of 62 children, 51 (82 %) with latent RHD had a median follow-up period of 25 months. Of these 51 children, 17 (33.3 %) reported an interval sore throat or symptoms consistent with acute rheumatic fever (ARF). Of 43 children initially classified as having borderline RHD, 21 (49 %) remained stable, 18 (42 %) improved (to no RHD) and 4 (10 %) worsened to definite RHD. Of the 8 children initially classified as having definite RHD, 6 (75 %) remained stable, and 2 (25 %) improved to borderline RHD. Two children had confirmed episodes of recurrent ARF, one of which represented the sole case of clinical worsening. The risk factors for disease persistence or progression included younger age (p = 0.05), higher antistreptolysin O titers at diagnosis (p = 0.05), and more morphologic valve abnormalities (p = 0.01). After 2 years, most of the children had a benign course, with 91 % remaining stable or showing improvement. Education may improve recognition of streptococcal sore throat. Longer-term follow-up evaluation, however, is warranted to confirm disease progression and risk factor profile. This could help tailor screening protocols for those at highest risk.

  6. Investigation of soil contamination at the Riot Control Burning Pit area in J-Field, Aberdeen Proving Ground, Maryland

    SciTech Connect

    Wang, Ying-Ya; Yuen, C.R.; Martino, L.

    1996-05-01

    A remedial investigation was conducted to identify soil contamination in the Riot Control Burning Pit area in J-field, Aberdeen Proving Ground, Maryland. The investigation included geophysical surveys to delineate the filled section of the pit, soil-gas surveys to locate the organic contamination area, field X-ray fluorescence measurements along the burning pit to identify the major metal contamination, and surface and subsurface soil analyses to investigate the nature and extent of contamination. This paper presents the results of this investigation

  7. Field-scale transplantation experiment to investigate structures of soil bacterial communities at pioneering sites.

    PubMed

    Lazzaro, Anna; Gauer, Andreas; Zeyer, Josef

    2011-12-01

    Studies on the effect of environmental conditions on plants and microorganisms are a central issue in ecology, and they require an adequate experimental setup. A strategy often applied in geobotanical studies is based on the reciprocal transplantation of plant species at different sites. We adopted a similar approach as a field-based tool to investigate the relationships of soil bacterial communities with the environment. Soil samples from two different (calcareous and siliceous) unvegetated glacier forefields were reciprocally transplanted and incubated for 15 months between 2009 and 2010. Controls containing local soils were included. The sites were characterized over time in terms of geographical (bedrock, exposition, sunlight, temperature, and precipitation) and physicochemical (texture, water content, soluble and nutrients) features. The incubating local ("home") and transplanted ("away") soils were monitored for changes in extractable nutrients and in the bacterial community structure, defined through terminal restriction fragment length polymorphism (T-RFLP) of the 16S rRNA gene. Concentrations of soluble ions in most samples were more significantly affected by seasons than by the transplantation. For example, NO(3)(-) showed a seasonal pattern, increasing from 1 to 3 μg NO(3)(-) (g soil dry weight)(-1) after the melting of snow but decreasing to <1 μg NO(3)(-) (g soil dry weight)(-1) in autumn. Seasons, and in particular strong precipitation events occurring in the summer of 2010 (200 to 300 mm of rain monthly), were also related to changes of bacterial community structures. Our results show the suitability of this approach to compare responses of bacterial communities to different environmental conditions directly in the field.

  8. Investigation of a direct effect of nanosecond pulse electric fields on mitochondria

    NASA Astrophysics Data System (ADS)

    Estlack, Larry E.; Roth, Caleb C.; Cerna, Cesario Z.; Wilmink, Gerald J.; Ibey, Bennett L.

    2014-03-01

    The unique cellular response to nanosecond pulsed electric field (nsPEF) exposure, as compared to longer pulse exposure, has been theorized to be due to permeabilization of intracellular organelles including the mitochondria. In this investigation, we utilized a high-throughput oxygen and pH sensing system (Seahorse® XF24 extracellular flux analyzer) to assess the mitochondrial activity of Jurkat and U937 cells after nsPEF. The XF Analyzer uses a transient micro-chamber of only a few μL in specialized cell culture micro-plates to enable oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) to be monitored in real-time. We found that for nsPEF exposures of 10 pulses at 10-ns pulse width and at 50 kV/cm e-field, we were able to cause an increase in OCR in both U937 and Jurkat cells. We also found that high pulse numbers (>100) caused a significant decrease in OCR. Higher amplitude 150 kV/cm exposures had no effect on U937 cells and yet they had a deleterious effect on Jurkat cells, matching previously published 24 hour survival data. These results suggest that the exposures were modulating metabolic activity in cells possibly due to direct effects on the mitochondria themselves. To validate this hypothesis, we isolated mitochondria from U937 cells and exposed them similarly and found no significant change in metabolic activity for any pulse number. In a final experiment, we removed calcium from the buffer solution that the cells were exposed in and found that no significant enhancement in metabolic activity was observed. These results suggest that direct permeabilization of the mitochondria is unlikely a primary effect of nsPEF exposure and calcium-mediated intracellular pathway activation is likely responsible for observed pulse-induced mitochondrial effects.

  9. Saliva in perimenopausal and early postmenopausal women. A 2-year follow-up study.

    PubMed

    Tarkkila, Laura; Furuholm, Jussi; Tiitinen, Aila; Meurman, Jukka H

    2012-06-01

    This study aims to investigate salivary flow and biochemical constituents of menopausal-age women with the hypothesis that women using hormone therapy (HT) might present better saliva values than non-users. Two hundred HT users and 200 non-users were selected at random from a cohort study of 3,173 peri- and postmenopausal women and invited to a 2-year clinical follow-up study. Clinical examination with saliva sampling was made at baseline and 2 years later. Salivary total protein, albumin, and immunoglobulin (Ig) concentrations were analyzed. Final material included 106 consistent HT users and 55 non-users. Backward logistic regression analysis was made to determine the risk factors for higher or lower than medium salivary protein values. No difference was seen in salivary flow rate, total protein, and IgA values between baseline and follow-up measurements or between the groups. Albumin, IgG, and IgM concentrations were significantly lower in the 2-year samples of the HT group when compared with baseline. IgA and IgM values were higher in the non-HT 2-year samples when compared with the corresponding HT samples. The only significant explanatory factor for higher than median salivary albumin concentration was the number of teeth both at baseline and 2 years later. HT possibly improved epithelial integrity since the concentrations of serum components albumin, IgG, and IgM decreased during the follow-up. HT as such does not seem to affect saliva, although it may modify it. The clinical relevance of these results needs to be assessed in future studies.

  10. Compound specific isotope analysis to investigate pesticide degradation in lysimeter experiments at field conditions

    NASA Astrophysics Data System (ADS)

    Ryabenko, Evgenia; Elsner, Martin; Bakkour, Rani; Hofstetter, Thomas; Torrento, Clara; Hunkeler, Daniel

    2015-04-01

    The frequent detection of organic micropollutants such as pesticides, consumer care products or pharmaceuticals in water is an increasing concern for human and ecosystem health. Degradation analysis of these compounds can be challenging in complex systems due to the fact that metabolites are not always found and mass balances frequently cannot be closed. Many abiotic and biotic degradation pathways cause, however, distinct isotope fractionation, where light isotopes are transferred preferentially from the reactant to the product pool (normal isotope fractionation). Compound-specific isotope analysis (CSIA) of multiple elements is a particularly powerful method to evaluate organic micropollutant transformation, because it can even give pathway-specific isotope fractionation (1,2). Available CSIA field studies, however, have focused almost exclusively on volatile petroleum and chlorinated hydrocarbons, which are present in high concentrations in the environment and can be extracted easily from water for GC-IRMS analysis. In the case of micropollutants, such as pesticides, CSIA in more challenging since it needs to be conducted at lower concentrations and requires pre-concentration, purification and high chromatographic performance (3). In this study we used lysimeters experiments to analyze transformation of atrazine, acetochlor, metolachlor and chloridazone by studying associated isotope fractionation. The project combines a) analytical method development for CSIA, b) identification of pathways of micropollutant degradation and c) quantification of transformation processes under field condition. The pesticides were applied both, at the soil surface and below the top soil under field-relevant concentrations in May 2014. After typical irrigation of the lysimeters, seepage water was collected in 50L bottles and stored for further SPE and CSIA. Here we present the very first result of a) analytical method development, b) improvement of SPE methods for complex pesticide

  11. Full-field Strain Methods for Investigating Failure Mechanisms in Triaxial Braided Composites

    NASA Technical Reports Server (NTRS)

    Littell, Justin D.; Binienda, Wieslaw K.; Goldberg, Robert K.; Roberts, Gary D.

    2008-01-01

    Composite materials made with triaxial braid architecture and large tow size carbon fibers are beginning to be used in many applications, including composite aircraft and engine structures. Recent advancements in braiding technology have led to commercially viable manufacturing approaches for making large structures with complex shape. Although the large unit cell size of these materials is an advantage for manufacturing efficiency, the fiber architecture presents some challenges for materials characterization, design, and analysis. In some cases, the static load capability of structures made using these materials has been higher than expected based on material strength properties measured using standard coupon tests. A potential problem with using standard tests methods for these materials is that the unit cell size can be an unacceptably large fraction of the specimen dimensions. More detailed investigation of deformation and failure processes in large unit cell size triaxial braid composites is needed to evaluate the applicability of standard test methods for these materials and to develop alternative testing approaches. In recent years, commercial equipment has become available that enables digital image correlation to be used on a more routine basis for investigation of full field 3D deformation in materials and structures. In this paper, some new techniques that have been developed to investigate local deformation and failure using digital image correlation techniques are presented. The methods were used to measure both local and global strains during standard straight-sided coupon tensile tests on composite materials made with 12 and 24 k yarns and a 0/+60/-60 triaxial braid architecture. Local deformation and failure within fiber bundles was observed, and this local failure had a significant effect on global stiffness and strength. The matrix material had a large effect on local damage initiation for the two matrix materials used in this investigation

  12. Investigating microbial transformations of soil organic matter: synthesizing knowledge from disparate fields to guide new experimentation

    NASA Astrophysics Data System (ADS)

    Billings, S. A.; Tiemann, L. K.; Ballantyne, F., IV; Lehmeier, C.; Min, K.

    2014-12-01

    Investigators of soil organic matter (SOM) transformations struggle with a deceptively simple-sounding question: "Why does some SOM leave the soil profile relatively quickly, while other compounds, especially those at depth, appear to be retained on timescales ranging from the decadal to the millennial?" This question is important on both practical and academic levels, but addressing it is challenging for a multitude of reasons. Simultaneous with soil-specific advances, multiple other disciplines have enhanced their knowledge bases in ways potentially useful for future investigations of SOM decay. In this article, we highlight observations highly relevant for those investigating SOM decay and retention but often emanating from disparate fields and residing in literature seldom cited in SOM research. We focus on recent work in two key areas. First, we turn to experimental approaches using natural and artificial aquatic environments to investigate patterns of microbially-mediated OM transformations as environmental conditions change, and highlight how aquatic microbial responses to environmental change can reveal processes likely important to OM decay and retention in soils. Second, we emphasize the importance of establishing intrinsic patterns of decay kinetics for purified substrates commonly found in soils to develop baseline rates. These decay kinetics - which represent the upper limit of the reaction rates - can then be compared to substrate decay kinetics observed in natural samples, which integrate intrinsic decay reaction rates and edaphic factors essential to the site under study but absent in purified systems. That comparison permits the site-specific factors to be parsed from the fundamental decay kinetics, an important advance in our understanding of SOM decay (and thus persistence) in natural systems. We then suggest ways in which empirical observations from aquatic systems and purified enzyme-substrate reaction kinetics can be used to advance recent

  13. Schmallenberg virus infection in South American camelids: Field and experimental investigations.

    PubMed

    Schulz, Claudia; Beer, Martin; Hoffmann, Bernd

    2015-11-18

    During the first epizootic wave of the novel, teratogenic Schmallenberg virus (SBV, Orthobunyavirus) in ruminants in Northern Europe, serological evidence of a previous SBV-infection demonstrated that South American camelids (SAC) are also susceptible to SBV. However, their potential role in SBV spread remains unknown. To investigate the prevalence and course of SBV-infection in SAC, a German field study and an animal trial with three llamas and three alpacas were conducted. From September 2012 to December 2013, 313 of 502 SAC (62.35%) were found SBV seropositive, but negative for SBV-RNA. The estimated between-district (94.23% of 52) and median within-district (71.43%) and herd (73.13%) SBV seroprevalence in German SAC was similar to the seroprevalence reported in cattle herds and sheep flocks at the time. An age of >1 year was found a statistically significant risk factor for SBV-infection, which could be explained by the spatio-temporal spread of SBV in Germany during the study period. No clinical signs or an increase of abortion and congenital malformation associated with SBV-infection in SAC were reported by the study participants. Similar to SBV-infected ruminants, SBV-RNAemia in experimentally SBV-infected SAC was detected for a short time between days 3 and 7 after infection (dpi), and seroconversion occurred between 9 and 21 dpi. Despite the similar virological and serological results, the lack of clinical signs and congenital malformation associated with SBV-infection suggests that SBV causes subclinical infection in SAC. However, their role as reservoirs in the spread of SBV has to be further investigated.

  14. A real-scale field experiment of debris flow for investigating its deposition and entrainment

    NASA Astrophysics Data System (ADS)

    Paik, J.; Son, S.; Kim, T.; Kim, S.

    2012-12-01

    In mountain area debris flows typically mobilize from slides and entrain channel materials as they propagate down over the surface of hill slope and valley. Consequently, cross-sectional averaged discharge of debris flows may increases due to the entrainment of channel materials over steep slopes while decrease due to deposition of large material at mile slopes. In this work, the erosional and depositional patterns of debris flow have been investigated through a real-scale field experiment in a mountain basin in Gangwon, Korea. The experimental basin is about 800 m long and the channel width ranges between 8 m and 25 m. The angle of the channel slope varies from 38° near the upstream end to 5° at the downstream end where a check has been installed. In the experiment, 300 cubic meters of saturated solid-fluid mixture is suddenly released by opening a gate of a concrete reservoir installed at the upstream of the basin, along with additional 10.0 cubic meters of water per second for 30 seconds. We employ several sensors for measuring the speed, depth variation and total normal and fluid pore pressures at the channel bed as the debris flow propagates downslope. The velocity and depth of the debris flow are measured using ultrasonic sensors with a measuring range up to 10 m and video recording systems. A load cell and eight pore pressure transducers ranging up 30 psia are used to measure the total normal and pore-water pressures at the base of the debris flow. Through a quantitative analysis of these experimental measurements and high-resolution LiDAR topographic data we investigate the deposition and entrainment features of debris flow. We introduce the details of the full-scale experimental basin, facility, sensors and procedure, and provide some our experimental observations.

  15. Interface Charge Transport in Organic Transistors as Investigated by Field-Induced Electron Spin Resonance

    NASA Astrophysics Data System (ADS)

    Hasegawa, Tatsuo

    2013-03-01

    Most of high-performance organic thin-film transistors (OTFTs) as recently developed is attainable with non-doped, single-component π-conjugated materials that exhibit high layer crystallinity both for small-molecules and polymers. The layer crystallinity is quite suitable to compose channel transport layers of the OTFTs, although the main origin to hinder the charge transport or the intrinsic carrier mobility is still controversial; intra- or intermolecular electron-phonon coupling, polarization effects by the gate-dielectrics, or thermal or extrinsic disorder effects. Here we discuss the interface charge transport in the OTFTs, as investigated by field-induced electron spin resonance (FESR) technique that probes 1/2 spin of carriers induced by gate voltage. It is shown that the FESR technique is extremely useful especially for OTFTs, because of the fairly small spin-orbit interactions in organic materials as well as of the high layer crystallinity and the anisotropy. The following important aspects of the interface charge transport are presented and discussed: (1) Carrier motion in OTFTs can be understood in terms of the multiple trap-and-release (MTR) transport. The analyses of the motional narrowing effects allow us to estimate the average trap residence time that reaches about 1 ns. (2) Carriers are frozen at the respective trap sites at low temperature. The low-temperature spectral analyses allow us to obtain the distribution of trapped carriers over their degree of localization. (3) We also developed a unique technique to investigate the intra- and inter-domain transport in polycrystalline OTFTs by using anisotropic FESR measurements. The method allows us to evaluate the potential barrier height at the domain boundaries within the films.

  16. The SERMON project: 48 new field Blazhko stars and an investigation of modulation-period distribution

    NASA Astrophysics Data System (ADS)

    Skarka, M.; Liška, J.; Auer, R. F.; Prudil, Z.; Juráňová, A.; Sódor, Á.

    2016-08-01

    Aims: We investigated 1234 fundamental mode RR Lyrae stars observed by the All Sky Automated Survey (ASAS) to identify the Blazhko (BL) effect. A sample of 1547 BL stars from the literature was collected to compare the modulation-period distribution with stars newly identified in our sample. Methods: A classical frequency spectra analysis was performed using Period04 software. Data points from each star from the ASAS database were analysed individually to avoid confusion with artificial peaks and aliases. Statistical methods were used in the investigation of the modulation-period distribution. Results: Altogether we identified 87 BL stars (48 new detections), 7 candidate stars, and 22 stars showing long-term period variations. The distribution of modulation periods of newly identified BL stars corresponds well to the distribution of modulation periods of stars located in the Galactic field, Galactic bulge, Large Magellanic Cloud, and globular cluster M5 collected from the literature. As a very important by-product of this comparison, we found that pulsation periods of BL stars follow Gaussian distribution with the mean period of 0.54 ± 0.07 d, while the modulation periods show log-normal distribution with centre at log (Pm [d]) = 1.78 ± 0.30 dex. This means that 99.7% of all known modulated stars have BL periods between 7.6 and 478 days. We discuss the identification of long modulation periods and show, that a significant percentage of stars showing long-term period variations could be classified as BL stars.

  17. Field Investigation of a New Recharge Approach for ASR Projects in Near-Surface Aquifers.

    PubMed

    Liu, Gaisheng; Knobbe, Steven; Reboulet, Edward C; Whittemore, Donald O; Händel, Falk; Butler, James J

    2016-05-01

    Aquifer storage and recovery (ASR) is the artificial recharge and temporary storage of water in an aquifer when water is abundant, and recovery of all or a portion of that water when it is needed. One key limiting factor that still hinders the effectiveness of ASR is the high costs of constructing, maintaining, and operating the artificial recharge systems. Here we investigate a new recharge method for ASR in near-surface unconsolidated aquifers that uses small-diameter, low-cost wells installed with direct-push (DP) technology. The effectiveness of a DP well for ASR recharge is compared with that of a surface infiltration basin at a field site in north-central Kansas. The performance of the surface basin was poor at the site due to the presence of a shallow continuous clay layer, identified with DP profiling methods, that constrained the downward movement of infiltrated water and significantly reduced the basin recharge capacity. The DP well penetrated through this clay layer and was able to recharge water by gravity alone at a much higher rate. Most importantly, the costs of the DP well, including both the construction and land costs, were only a small fraction of those for the infiltration basin. This low-cost approach could significantly expand the applicability of ASR as a water resources management tool to entities with limited fiscal resources, such as many small municipalities and rural communities. The results of this investigation demonstrate the great potential of DP wells as a new recharge option for ASR projects in near-surface unconsolidated aquifers.

  18. A laboratory investigation of the variability of cloud reflected radiance fields

    NASA Technical Reports Server (NTRS)

    Mckee, T. B.; Cox, S. K.

    1986-01-01

    A method to determine the radiative properties of complex cloud fields was developed. A Cloud field optical simulator (CFOS) was constructed to simulate the interaction of cloud fields with visible radiation. The CFOS was verified by comparing experimental results from it with calculations performed with a Monte Carlo radiative transfer model. A software library was developed to process, reduce, and display CFOS data. The CFSOS was utilized to study the reflected radiane patterns from simulated cloud fields.

  19. The Application of Intensive Longitudinal Methods to Investigate Change: Stimulating the Field of Applied Family Research.

    PubMed

    Bamberger, Katharine T

    2016-03-01

    The use of intensive longitudinal methods (ILM)-rapid in situ assessment at micro timescales-can be overlaid on RCTs and other study designs in applied family research. Particularly, when done as part of a multiple timescale design-in bursts over macro timescales-ILM can advance the study of the mechanisms and effects of family interventions and processes of family change. ILM confers measurement benefits in accurately assessing momentary and variable experiences and captures fine-grained dynamic pictures of time-ordered processes. Thus, ILM allows opportunities to investigate new research questions about intervention effects on within-subject (i.e., within-person, within-family) variability (i.e., dynamic constructs) and about the time-ordered change process that interventions induce in families and family members beginning with the first intervention session. This paper discusses the need and rationale for applying ILM to family intervention evaluation, new research questions that can be addressed with ILM, example research using ILM in the related fields of basic family research and the evaluation of individual-based interventions. Finally, the paper touches on practical challenges and considerations associated with ILM and points readers to resources for the application of ILM.

  20. Numerical investigations on electric field characteristics with respect to capacitive detection of free-flying droplets.

    PubMed

    Ernst, Andreas; Mutschler, Klaus; Tanguy, Laurent; Paust, Nils; Zengerle, Roland; Koltay, Peter

    2012-01-01

    In this paper a multi-disciplinary simulation of a capacitive droplet sensor based on an open plate capacitor as transducing element is presented. The numerical simulations are based on the finite volume method (FVM), including calculations of an electric field which changes according to the presence of a liquid droplet. The volume of fluid (VOF) method is applied for the simulation of the ejection process of a liquid droplet out of a dispenser nozzle. The simulations were realised using the computational fluid dynamic (CFD) software CFD ACE+. The investigated capacitive sensing principle enables to determine the volume of a micro droplet passing the sensor capacitor due to the induced change in capacity. It could be found that single droplets in the considered volume range of 5 nL < V(drop) < 100 nL lead to a linear change of the capacity up to ΔQ < 30 fC. The sensitivity of the focused capacitor geometry was evaluated to be S(i) = 0.3 fC/nL. The simulation results are validated by experiments which exhibit good agreement.

  1. Formation mechanism of gas bubble superlattice in UMo metal fuels: Phase-field modeling investigation

    NASA Astrophysics Data System (ADS)

    Hu, Shenyang; Burkes, Douglas E.; Lavender, Curt A.; Senor, David J.; Setyawan, Wahyu; Xu, Zhijie

    2016-10-01

    Nano-gas bubble superlattices are often observed in irradiated UMo nuclear fuels. However, the formation mechanism of gas bubble superlattices is not well understood. A number of physical processes may affect the gas bubble nucleation and growth; hence, the morphology of gas bubble microstructures including size and spatial distributions. In this work, a phase-field model integrating a first-passage Monte Carlo method to investigate the formation mechanism of gas bubble superlattices was developed. Six physical processes are taken into account in the model: 1) heterogeneous generation of gas atoms, vacancies, and interstitials informed from atomistic simulations; 2) one-dimensional (1-D) migration of interstitials; 3) irradiation-induced dissolution of gas atoms; 4) recombination between vacancies and interstitials; 5) elastic interaction; and 6) heterogeneous nucleation of gas bubbles. We found that the elastic interaction doesn't cause the gas bubble alignment, and fast 1-D migration of interstitials along <110> directions in the body-centered cubic U matrix causes the gas bubble alignment along <110> directions. It implies that 1-D interstitial migration along [110] direction should be the primary mechanism of a fcc gas bubble superlattice which is observed in bcc UMo alloys. Simulations also show that fission rates, saturated gas concentration, and elastic interaction all affect the morphology of gas bubble microstructures.

  2. Geological and geophysical field investigations from a lunar base at Mare Smythii

    NASA Technical Reports Server (NTRS)

    Spudis, Paul D.; Hood, Lon L.

    1992-01-01

    Mare Smythii, located on the equator and east limb of the Moon, has a great variety of scientific and economic uses as the site for a permanent lunar base. Here a complex could be established that would combine the advantages of a nearside base (for ease of communications with Earth and normal operations) with those of a farside base (for shielding a radio astronomical observatory from the electromagnetic noise of Earth). The Mare Smythii region displays virtually the entire known range of geological processes and materials found on the Moon; from this site, a series of field traverses and investigations could be conducted that would provide data on and answers to fundamental questions in lunar geoscience. This endowment of geological materials also makes the Smythii region attractive for the mining of resources for use both on the Moon and in Earth-Moon space. We suggest that the main base complex be located at 0, 90 deg E, within the mare basalts of the Smythii basin; two additional outposts would be required, one at 0, 81 deg E to maintain constant communications with Earth, and and the other, at 0, 101 deg E on the lunar farside, to serve as a radio astronomical observatory. The bulk of lunar surface activities could be conducted by robotic teleoperations under the direct control of the human inhabitants of the base.

  3. A field study investigating effects of landmarks on territory size and shape

    PubMed Central

    Suriyampola, Piyumika S.; Eason, Perri K.

    2014-01-01

    Few studies have examined how landmarks affect territories' fundamental characteristics. In this field study, we investigated effects of landmarks on territory size, shape and location in a cichlid fish (Amatitlania siquia). We provided cans as breeding sites and used plastic plants as landmarks. During 10 min trials, we recorded locations where residents chased intruders and used those locations to outline and measure the territory. In two experiments, we observed pairs without landmarks and with either a point landmark (one plant) or linear landmark (four plants) placed near the nest can. We alternated which trial occurred first and performed the second trial 24 h after the first. Territories were approximately round without landmarks or with a point landmark but were significantly more elongated when we added a linear landmark. Without landmarks, nests were centrally located; however, with any landmark, pairs set territory boundaries closer to the landmark and thus the nest. Territory size was significantly reduced in the presence of any landmark. This reduction suggests that a smaller territory with well-defined boundaries has greater benefits than a larger territory with less well-defined borders. PMID:24759367

  4. A field study investigating effects of landmarks on territory size and shape.

    PubMed

    Suriyampola, Piyumika S; Eason, Perri K

    2014-01-01

    Few studies have examined how landmarks affect territories' fundamental characteristics. In this field study, we investigated effects of landmarks on territory size, shape and location in a cichlid fish (Amatitlania siquia). We provided cans as breeding sites and used plastic plants as landmarks. During 10 min trials, we recorded locations where residents chased intruders and used those locations to outline and measure the territory. In two experiments, we observed pairs without landmarks and with either a point landmark (one plant) or linear landmark (four plants) placed near the nest can. We alternated which trial occurred first and performed the second trial 24 h after the first. Territories were approximately round without landmarks or with a point landmark but were significantly more elongated when we added a linear landmark. Without landmarks, nests were centrally located; however, with any landmark, pairs set territory boundaries closer to the landmark and thus the nest. Territory size was significantly reduced in the presence of any landmark. This reduction suggests that a smaller territory with well-defined boundaries has greater benefits than a larger territory with less well-defined borders.

  5. Investigation of single- and double-Λ hypernuclei using a beyond-mean-field approach

    NASA Astrophysics Data System (ADS)

    Cui, Ji-Wei; Zhou, Xian-Rong; Guo, Li-Xin; Schulze, Hans-Josef

    2017-02-01

    A beyond-mean-field approach consisting of angular momentum projection techniques and generator coordinate method based on Skyrme-Hartree-Fock calculations is employed to investigate single- and double-Λ hypernuclear systems. The density-dependent N Λ interactions derived from the Nijmegen soft-core potentials are used. Rotational energy spectra and electric-quadrupole transition strengths B (E 2 ) of the hypernuclei 13CΛ, 14CΛ Λ, 21Ne21Λ, and 22NeΛ Λ are presented and compared with those of the corresponding core nuclei 12C and 20Ne. The shrinkage effect of the Λ s is demonstrated by the B (E 2 ) values, the charge radii, and the shape deformation β of the nuclear core. It is found that the reduction of the B (E 2 ) values in 13CΛ and 14CΛΛ is mainly caused by the shrinkage of the charge radii of the nuclear cores, while the reduced shape deformations also play important roles; but the contrary is the case in Ne21Λ and 22NeΛΛ. Comparison between this and other theoretical models are made, and the differences between them are illuminated.

  6. The Application of Intensive Longitudinal Methods to Investigate Change: Stimulating the Field of Applied Family Research

    PubMed Central

    Bamberger, Katharine T.

    2015-01-01

    The use of intensive longitudinal methods (ILM)—rapid in situ assessment at micro timescales—can be overlaid on RCTs and other study designs in applied family research. Especially when done as part of a multiple timescale design—in bursts over macro timescales, ILM can advance the study of the mechanisms and effects of family interventions and processes of family change. ILM confers measurement benefits in accurately assessing momentary and variable experiences and captures fine-grained dynamic pictures of time-ordered processes. Thus, ILM allows opportunities to investigate new research questions about intervention effects on within-subject (i.e., within-person, within-family) variability (i.e., dynamic constructs) and about the time-ordered change process that interventions induce in families and family members beginning with the first intervention session. This paper discusses the need and rationale for applying ILM to intervention evaluation, new research questions that can be addressed with ILM, example research using ILM in the related fields of basic family research and the evaluation of individual-based (rather than family-based) interventions. Finally, the paper touches on practical challenges and considerations associated with ILM and points readers to resources for the application of ILM. PMID:26541560

  7. Atmospheric Radiation Measurement Madden-Julian Oscillation Investigation Experiment Field Campaign Report

    SciTech Connect

    Long, Chuck

    2016-07-01

    Every 30–90 days during the Northern Hemisphere winter, the equatorial tropical atmosphere experiences pulses of extraordinarily strong deep convection and rainfall. This phenomenon is referred to as the Madden–Julian Oscillation, or MJO, named after the scientists who identified this cycle. The MJO significantly affects weather and rainfall patterns around the world (Zhang 2013). To improve predictions of the MJO—especially about how it forms and evolves throughout its lifecycle—an international group of scientists collected an unprecedented set of observations from the Indian Ocean and western Pacific region from October 2011 through March 2012 through several coordinated efforts. The coordinated field campaigns captured six distinct MJO cycles in the Indian Ocean. The rich set of observations capturing several MJO events from these efforts will be used for many years to study the physics of the MJO. Here we highlight early research results using data from the Atmospheric Radiation Measurement (ARM) Madden-Julian Oscillation Investigation Experiment (AMIE), sponsored by the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility.

  8. Passenger thermal comfort and behavior: a field investigation in commercial aircraft cabins.

    PubMed

    Cui, W; Wu, T; Ouyang, Q; Zhu, Y

    2017-01-01

    Passengers' behavioral adjustments warrant greater attention in thermal comfort research in aircraft cabins. Thus, a field investigation on 10 commercial aircrafts was conducted. Environment measurements were made and a questionnaire survey was performed. In the questionnaire, passengers were asked to evaluate their thermal comfort and record their adjustments regarding the usage of blankets and ventilation nozzles. The results indicate that behavioral adjustments in the cabin and the use of blankets or nozzle adjustments were employed by 2/3 of the passengers. However, the thermal comfort evaluations by these passengers were not as good as the evaluations by passengers who did not perform any adjustments. Possible causes such as differences in metabolic rate, clothing insulation and radiation asymmetry are discussed. The individual difference seems to be the most probable contributor, suggesting possibly that passengers who made adjustments had a narrower acceptance threshold or a higher expectancy regarding the cabin environment. Local thermal comfort was closely related to the adjustments and significantly influenced overall thermal comfort. Frequent flying was associated with lower ratings for the cabin environment.

  9. Investigation of dielectric pocket induced variations in tunnel field effect transistor

    NASA Astrophysics Data System (ADS)

    Upasana; Narang, Rakhi; Saxena, Manoj; Gupta, Mridula

    2016-04-01

    The performance of conventional Tunnel FETs struggling from ambipolar issues, insufficient on-current, lower transconductance value, higher delay and lower cut off frequency has been improved by introducing several material and device engineering concepts in past few years. Keeping this in view, another interesting and reliable option i.e. Dielectric Pocket TFET (featuring a dielectric pocket placement near tunneling junction) has been comprehensively and qualitatively demonstrated using ATLAS device simulator. The architecture has been explored in terms of various device electrostatic parameters such as potential, energy band profile, electron and hole concentration, electric field variation and band to band generation rate (GBTB) near the tunneling junction where the Dielectric Pocket (DP) has been introduced. Subsequently, a detailed investigation by changing the position and dielectric constant of pocket at respective junctions has been made where DP induced variations in drain current, transconductance and parasitic capacitance have been examined. The work highlights major improvements over conventional TFET in terms of lower subthreshold swing and threshold voltage, higher drain current and transconductance, improved on-to-off current ratio, suppressed ambipolar conduction and improved dynamic power dissipation issues for low voltage analog and digital applications.

  10. Formation mechanism of gas bubble superlattice in UMo metal fuels: Phase-field modeling investigation

    SciTech Connect

    Hu, Shenyang; Burkes, Douglas E.; Lavender, Curt A.; Senor, David J.; Setyawan, Wahyu; Xu, Zhijie

    2016-07-08

    Nano-gas bubble superlattices are often observed in irradiated UMo nuclear fuels. However, the for- mation mechanism of gas bubble superlattices is not well understood. A number of physical processes may affect the gas bubble nucleation and growth; hence, the morphology of gas bubble microstructures including size and spatial distributions. In this work, a phase-field model integrating a first-passage Monte Carlo method to investigate the formation mechanism of gas bubble superlattices was devel- oped. Six physical processes are taken into account in the model: 1) heterogeneous generation of gas atoms, vacancies, and interstitials informed from atomistic simulations; 2) one-dimensional (1-D) migration of interstitials; 3) irradiation-induced dissolution of gas atoms; 4) recombination between vacancies and interstitials; 5) elastic interaction; and 6) heterogeneous nucleation of gas bubbles. We found that the elastic interaction doesn’t cause the gas bubble alignment, and fast 1-D migration of interstitials along $\\langle$110$\\rangle$ directions in the body-centered cubic U matrix causes the gas bubble alignment along $\\langle$110$\\rangle$ directions. It implies that 1-D interstitial migration along [110] direction should be the primary mechanism of a fcc gas bubble superlattice which is observed in bcc UMo alloys. Simulations also show that fission rates, saturated gas concentration, and elastic interaction all affect the morphology of gas bubble microstructures.

  11. Language experiences and vocabulary development in Dominican and Mexican infants across the first 2 years.

    PubMed

    Song, Lulu; Tamis-Lemonda, Catherine S; Yoshikawa, Hirokazu; Kahana-Kalman, Ronit; Wu, Irene

    2012-07-01

    We longitudinally investigated parental language context and infants' language experiences in relation to Dominican American and Mexican American infants' vocabularies. Mothers provided information on parental language context, comprising measures of parents' language background (i.e., childhood language) and current language use during interviews at infants' birth. Infants' language experiences were measured at ages 14 months and 2 years through mothers' reports of mothers' and fathers' engagement in English and Spanish literacy activities with infants and mothers' English and Spanish utterances during videotaped mother-infant interactions. Infants' vocabulary development at 14 months and 2 years was examined using standardized vocabulary checklists in English and Spanish. Both parental language context and infants' language experiences predicted infants' vocabularies in each language at both ages. Furthermore, language experiences mediated associations between parental language context and infants' vocabularies. However, the specific mediation mechanisms varied by language.

  12. Investigation of the Influence of Magnetospheric Sources of Field-Aligned Currents on the Equatorial Electric Fields

    NASA Astrophysics Data System (ADS)

    Beloushko, Konstantin; Knyazeva, Mariya

    The urgency of studying electrodynamic processes related to the influence of spatial and temporal heterogeneities of the electromagnetic field in the Earth's upper atmosphere to the functioning of modern technological systems , satellite navigation systems , radio propagation Fundamentally new is the use of various third-party electrodynamic models in the total open loop model of the atmosphere based on the Upper Atmosphere Model (UAM) [1,2]. Performing calculations on model UAM using different spatial and temporal distributions of field-aligned currents and brands Lukianova and Papitashvili. A comparison of model results with data Jicamarca Incoherent Scatter Radar (Peru). References begin{enumerate} Namgaladze A.A., Korenkov Yu.N., Klimenko V.V., Karpov I.V., Bessarab F.S., Surotkin V.A., Gluschenko T.A., Naumova N.M. Global model of the thermosphere-ionosphere-protonosphere system. Pure and Applied Geophysics. № 2/3, 127, 219-254, 1988. Namgaladze A.A., Martynenko O.V., Namgaladze A.N. Global model of the upper atmosphere with variable latitudinal steps of numerical integration, IUGG XXI General Assembly, Boulder, 1995, Abstracts, GAB41F-6, B150, 1995, and (in Russian) Geamagn. Aeron., 36, 89-95, 1996a.

  13. Colloid-Facilitated Transport of Low-Solubility Radionuclides: A Field, Experimental, and Modeling Investigation

    SciTech Connect

    Kersting, A B; Reimus, P W; Abdel-Fattah, A; Allen, P G; Anghel, I; Benedict, F C; Esser, B K; Lu, N; Kung, K S; Nelson, J; Neu, M P; Reilly, S D; Smith, D K; Sylwester, E R; Wang, L; Ware, S D; Warren, RG; Williams, R W; Zavarin, M; Zhao, P

    2003-02-01

    rate of Pu transport. Currently, the role of colloids in facilitating the transport of low-solubility radionuclides is not understood well enough to effectively model contaminant transport. A fundamental understanding of the role that colloids may or may not play in the transport of low-solubility radionuclides is needed in order to predict contaminant transport, design remediation strategies and provide risk assessments. Ryan and Elimelech (1996) have argued that in order to evaluate the potential for colloids to transport radionuclides, several criteria must be met: (1) colloids must exist and be stable, (2) radionuclides must have a high sorption affinity for the colloids, and (3) colloids must be transported. Only then can we understand the conditions where colloids can and will facilitate transport of radionuclides. In this report we compile the results from a series of field, laboratory and modeling studies funded by the UGTA program in order to evaluate the potential for colloids to transport low-solubility radionuclides at the NTS. The studies presented in this report fall under three general areas of investigation: Characterization of natural colloids in groundwater at NTS, Pu sorption/desorption experiments on colloid minerals identified in NTS groundwater, and Transport of Pu-doped colloids through fractured rock core. Chapter 1 is a background review of our current understanding of colloids and their role in facilitating contaminant transport. Chapters 2, and 3 are field studies that focused on characterizing natural colloids at different hydrologic environments at the NTS and address Ryan and Elimelech's (1996) first criteria regarding the existence and stability of colloids. Chapters 4, 5 and 6 are laboratory experimental studies that investigate the sorption/desorption behavior of Pu and other low-solubility radionuclides on colloid minerals observed in NTS groundwater. These studies evaluate Ryan and Elimelech's (1996) second criteria that the affinity

  14. New geoscience teachers division for 2-year colleges

    NASA Astrophysics Data System (ADS)

    Krumm, Debra; Granshaw, Frank

    2011-11-01

    The role of 2-year colleges (2YCs) in geoscience education is growing as the number of students enrolled in Earth and space science courses increases and as these institutions—which include community colleges and junior colleges—provide more students majoring in geoscience at public universities. In recognition of the increasing role of 2YCs in geoscience education, the National Association of Geoscience Teachers (NAGT) recently created a Geo2YC division for faculty, administrators, graduate students, and other geoscience professionals who share a professional interest in geoscience education at 2YCs. The mission of the new division, which is NAGT's first national division, is to serve as a forum for exchanging curricular ideas, concerns, and resources; establish a network of geoscience educators at 2YCs and other institutions with shared interests; sponsor NAGT 2YC activities and make recommendations to the NAGT Council in support of 2YC geoscience education; support and coordinate research on 2YC geoscience education; and advocate for 2YC geoscience education within NAGT and with other organizations.

  15. Tacrolimus ointment: utilization patterns in children under age 2 years.

    PubMed

    Housman, Tamara Salam; Norton, Amy B; Feldman, Steven R; Fleischer, Alan B; Simpson, Eric L; Hanifin, Jon M; Antaya, Richard J

    2004-07-15

    Atopic dermatitis (AD) is a common eczematous skin condition; as many as 10-17 percent of all children are affected, and 35-60 percent of affected patients manifest symptoms manifest during the first year of life. Treatment principles for AD in young children involve conservative measures such as avoidance of hot water and environmental irritants, combined with liberal use of emollients after bathing. Low potency topical corticosteroids (TCS) are the current standard of therapy for AD in young children, reserving mid- and high-potency TCS for severe disease. However, complications of long-term use of TCS include skin atrophy, stria formation, telangiectasia, hypopigmentation, secondary infections, steroid acne, allergic contact dermatitis, and miliaria. The pediatric population is also at increased risk for systemic absorption because of their high ratio of skin surface to body mass. Systemic absorption may result in hypothalamic-pituitary-adrenal axis suppression and ultimately growth retardation. Although most topical and systemic corticosteroids are not approved by the Food and Drug Administration for use in children less than 2 years of age, conservative treatment often fails in this age group and frequently patients are treated with TCS, antibiotics, and antihistamines.

  16. Cost and Schedule Analytical Techniques Development: Option 2 Year

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This Final Report summarizes the activities performed by Science Applications International Corporation (SAIC) for the Option 2 Year from December 1, 1996 through November 30, 1997. The Final Report is in compliance with Paragraph 5 of Section F of the contract. This CSATD contract provides products and deliverable in the form of models, data bases, methodologies, studies and analyses for the NASA Marshall Space Flight Center's (MSFC) Engineering Cost Office (PPO3) the Program Plans and Requirements Officer (PP02), and other user organizations. Detailed Monthly Progress reports were submitted to MSFC in accordance with the contract's Statement of Work, Section TV "Reporting and Documentation". These reports spelled out each month's specific work accomplishments, deliverables submitted, major meetings held, and other pertinent information. This Final Report will summarize these activities at higher level. During this contract Option Year, SAIC expended 29,830 man-hours in tile performance of tasks called out in the Statement of Work and reported oil in this yearly Final Report. This represents approximately 16 full-time EPs. Included are the basis Huntsville-based team, plus SAIC specialists in San Diego, Ames Research Center, Chicago, and Colorado Springs performing specific tasks for which they are uniquely qualified.

  17. Investigating the host galaxies of luminous AGN in the local universe with integral field spectroscopy

    NASA Astrophysics Data System (ADS)

    McElroy, Rebecca; Croom, Scott; Husemann, Bernd; Close AGN Reference Survey; SAMI Galaxy Survey

    2017-01-01

    This thesis investigates how galaxies and their super massive black holes coevolve. We use integral field spectroscopy to search for evidence of AGN feedback and triggering. We demonstrate that outflows are ubiquitous among luminous local type 2 AGN using observations from the AAT's SPIRAL instrument. Using multiple component Gaussian emission line decomposition we are able to disentangle the kinematic and ionisation properties of these winds. This allows us to argue that the outflows from these AGN are directly impacting the surrounding ISM within the galaxies. We search for evidence of AGN triggering using data from The Close AGN Reference Survey (CARS). CARS aims to provide a detailed multi-wavelength view of 40 nearby (0.01 < z < 0.06) unobscured AGN to study the link between AGN and their host galaxies. The primary CARS observations come from the MUSE integral field unit on the VLT, and complementary multi-wavelength observations have been approved from SOFIA, Chandra, VLA, HST, and others. We compare the stellar kinematics of active galaxies from CARS to similar inactive galaxies. We then use kinemetry to estimate the degree of dynamical disturbance, to determine whether active nuclei are preferentially hosted in dynamically disturbed or merging systems. Finally, we highlight the discovery of an AGN that has changed spectral type not once, but twice. So called ‘changing look’ AGN are an uncommon phenomenon, but twice changed AGN are much rarer. This AGN first transitioned from a narrow line AGN (type 2) to a broad line AGN (type 1) in the 1980s. It was recently observed as part of CARS. Examination of the MUSE data for this particular source showed that it no longer had the spectral features typical of a type 1 AGN. The continuum emission from the accretion disk was no longer visible and the broad lines were dramatically diminished. In this talk we describe the possible reasons for this change, supported by analysis of multi-epoch optical photometry and

  18. Field sampling and analysis plan for the remedial investigation of Waste Area Grouping 2 at Oak Ridge National Laboratory, Oak Ridge, Tennessee. Environmental Restoration Program

    SciTech Connect

    Boston, H.L.; Ashwood, T.L.; Borders, D.M.; Chidambariah, V.; Downing, D.J.; Fontaine, T.A.; Ketelle, R.H.; Lee, S.Y.; Miller, D.E.; Moore, G.K.; Suter, G.W.; Tardiff, M.F.; Watts, J.A.; Wickliff, D.S.

    1992-02-01

    This field sampling and analysis (S & A) plan has been developed as part of the Department of Energy`s (DOE`s) remedial investigation (RI) of Waste Area Grouping (WAG) 2 at Oak Ridge National Laboratory (ORNL) located in Oak Ridge, Tennessee. The S & A plan has been written in support of the remedial investigation (RI) plan for WAG 2 (ORNL 1990). WAG 2 consists of White Oak Creek (WOC) and its tributaries downstream of the ORNL main plant area, White Oak Lake (WOL), White Oak Creek embayment (WOCE) on the Clinch River, and the associated floodplain and subsurface environment (Fig. 1.1). The WOC system is the surface drainage for the major ORNL WAGs and has been exposed to a diversity of contaminants from operations and waste disposal activities in the WOC watershed. WAG 2 acts as a conduit through which hydrologic fluxes carry contaminants from upgradient areas to the Clinch River. Water, sediment, soil, and biota in WAG 2 are contaminated and continue to receive contaminants from upgradient WAGs. This document describes the following: an overview of the RI plan, background information for the WAG 2 system, and objectives of the S & A plan; the scope and implementation of the first 2 years of effort of the S & A plan and includes recent information about contaminants of concern, organization of S & A activities, interactions with other programs, and quality assurance specific to the S & A activities; provides details of the field sampling plans for sediment, surface water, groundwater, and biota, respectively; and describes the sample tracking and records management plan.

  19. A Further Investigation of the Effects of Extremely Low Frequency Magnetic Fields on Alkaline Phosphatase and Acetylcholinesterase

    PubMed Central

    Silkstone, Gary; Wilson, Michael T.

    2016-01-01

    Using a custom build spectrophotometer equipped with Helmholtz coils and designed to study the effects of magnetic fields on enzyme reactions in real-time we have investigated the influence of fields, from 100 μT to 10 mT and at a variety of field frequencies, on the membrane bound enzymes alkaline phosphatase and acetylcholinesterase. We have also employed other methods to apply a magnetic field, e.g. Biostim. In contrast to earlier reports we have been unable to detect any field effects on these enzymes under any field/frequency regime. We discuss possible reasons for the discrepancy between this and earlier work and note the particularly complex influence of small temperature changes that may confound analysis. PMID:26963611

  20. Integrating Field Measurements and Numerical Modeling to Investigate Gully Network Evolution

    NASA Astrophysics Data System (ADS)

    Rengers, F. K.; Tucker, G. E.

    2011-12-01

    With the advent of numerical modeling the exploration of landscape evolution has advanced from simple thought experiments to investigation of increasingly complex landforming processes. A common criticism of landscape evolution modeling, however, is the lack of model validation with actual field data. Here we present research that continues the advancement of landscape evolution theory by combining detailed field observations with numerical modeling. The focus of our investigation is gully networks on soft-rock strata, where rates of morphologic change are fast enough to measure on annual to decadal time scales. Our research focuses on a highly transient landscape on the high plains of eastern Colorado (40 miles east of Denver, CO) where convective thunderstorms drive ephemeral stream flow, resulting in incised gullies with vertical knickpoints. The site has yielded a comprehensive dataset of hydrology, topography, and geomorphic change. We are continuously monitoring several environmental parameters (including rainfall, overland flow, stream discharge, and soil moisture), and have explored the physical properties of the soil on the site through grain size analysis and infiltration measurements. In addition, time-lapse photography and repeat terrestrial lidar scanning make it possible to track knickpoint dynamics through time. The resulting dataset provides a case study for testing the ability of landscape evolution models to reproduce annual to decadal patterns of erosion and deposition. Knickpoint erosion is the largest contributor to landscape evolution and the controlling factor for gully migration rate. Average knickpoint retreat rates, based on historic aerial photographs and ongoing laser surveying, range between 0.1 and 2.5 m/yr. Knickpoint retreat appears to be driven by a combination of plunge-pool scour, large block failure, and grain-by-grain entrainment of sediment from the wall. Erosion is correlated with flash floods in the summer months. To test our

  1. Investigation of the Three-Dimensional Structure of a Rotating Magnetic Field Driven Field-Reversed Configuration using Internal Magnetic Field Measurements

    NASA Astrophysics Data System (ADS)

    Velas, Katherine M.

    The Translation, Confinement, Sustainment Upgrade device (TCSU) used a rotating magnetic field (RMF) to form and sustain plasma in a field-reversed configuration (FRC). The physics of RMF current drive can be modeled in terms of the torque acting on the FRC. A fully translatable three-axis internal magnetic probe was built and used to generate a full r-z map of the magnetic field in the FRC and open field line region. Probe measurements are used to calculate the torques acting on the FRC formed using even-parity and odd-parity RMF antenna configurations. Odd-parity current drive was found to be more efficient and yields a plasma with lower resistivity than in even-parity current drive. An extrapolation method was developed to generate 3D magnetic field line plots which show that unlike in even-parity, field lines in odd-parity sustained FRCs make multiple transits of the FRC. Analysis using the three-axis probe data has greatly expanded our understanding of the physics of RMF driven FRCs.

  2. Extensive lava flow fields on Venus: Preliminary investigation of source elevation and regional slope variations

    NASA Technical Reports Server (NTRS)

    Magee-Roberts, K.; Head, James W., III; Lancaster, M. G.

    1992-01-01

    Large-volume lava flow fields have been identified on Venus, the most areally extensive of which are known as fluctus and have been subdivided into six morphologic types. Sheetlike flow fields (Type 1) lack the numerous, closely spaced, discrete lava flow lobes that characterize digitate flow fields. Transitional flow fields (Type 2) are similar to sheetlike flow fields but contain one or more broad flow lobes. Digitate flow fields are divided further into divergent (Types 3-5) and subparallel (Type 6) classes on the basis of variations in the amount of downstream flow divergence. As a result of our previous analysis of the detailed morphology, stratigraphy, and tectonic associations of Mylitta Fluctus, we have formulated a number of questions to apply to all large flow fields on Venus. In particular, we would like to address the following: (1) eruption conditions and style of flow emplacement (effusion rate, eruption duration), (2) the nature of magma storage zones (presence of neutral buoyancy zones, deep or shallow crustal magma chambers), (3) the origin of melt and possible link to mantle plumes, and (4) the importance of large flow fields in plains evolution. To answer these questions we have begun to examine variations in flow field dimension and morphology; the distribution of large flow fields in terms of elevation above the mean planetary radius; links to regional tectonic or volcanic structures (e.g., associations with large shield edifices, coronae, or rift zones); statigraphic relationships between large flow fields, volcanic plains, shields, and coronae; and various models of flow emplacement in order to estimate eruption parameters. In this particular study, we have examined the proximal elevations and topographic slopes of 16 of the most distinctive flow fields that represent each of the 6 morphologic types.

  3. Geophysical investigations of well fields to characterize fractured-bedrock aquifers in southern New Hampshire

    USGS Publications Warehouse

    Degnan, James R.; Moore, Richard Bridge; Mack, Thomas J.

    2001-01-01

    Bedrock-fracture zones near high-yield bedrock wells in southern New Hampshire well fields were located and characterized using seven surface and six borehole geophysical survey methods. Detailed surveys of six sites with various methods provide an opportunity to integrate and compare survey results. Borehole geophysical surveys were conducted at three of the sites to confirm subsurface features. Hydrogeologic settings, including a variety of bedrock and surface geologic materials, were sought to gain an insight into the usefulness of the methods in varied terrains. Results from 15 survey lines, 8 arrays, and 3 boreholes were processed and interpreted from the 6 sites. The surface geophysical methods used provided physical properties of fractured bedrock. Seismic refraction and ground-penetrating radar (GPR) primarily were used to characterize the overburden materials, but in a few cases indicated bedrock-fracture zones. Magnetometer surveys were used to obtain background information about the bedrock to compare with other results, and to search for magnetic lows, which may result from weathered fractured rock. Electromagnetic terrain conductivity surveys (EM) and very-low-frequency electromagnetic surveys (VLF) were used as rapid reconnaissance techniques with the primary purpose of identifying electrical anomalies, indicating potential fracture zones in bedrock. Direct-current (dc) resistivity methods were used to gather detailed subsurface information about fracture depth and orientation. Two-dimensional (2-D) dc-resistivity surveys using dipole-dipole and Schlumberger arrays located and characterized the overburden, bedrock, and bedrock-fracture zones through analysis of data inversions. Azimuthal square array dc-resistivity survey results indicated orientations of conductive steep-dipping bedrock-fracture zones that were located and characterized by previously applied geophysical methods. Various available data sets were used for site selection

  4. Field and laboratory rainfall simulation as a tool to investigate Quaternary badland geomorphic development

    NASA Astrophysics Data System (ADS)

    Kuhn, Nikolaus; Kasanin-Grubin, Milica; Yair, Aaron; Rorke, Brian; Schwanghart, Wolfgang

    2010-05-01

    Badlands are traditionally considered as natural analogue experiments of landscape development. Commonly, their morphology is linked to lithological properties of the bedrock. However, recent investigations indicate that the geomorphic development is sensitive to climate and in particular to precipitation characteristics. This sensitivity enables the combination of rainfall simulation experiments with numerical models to study the relevance of climate change for their long-term geomorphic development. In this study, the relevance of precipitation characteristics for the Quaternary landscape development in the Dinosaur Badlands in Alberta, Canada, and Zin Valley Badlands, Negev Desert, Israel is investigated. Runoff, erosion and weathering were simulated in the field and the laboratory to determine rates for modeling different precipitation regimes. Based on the results, a numerical model was developed and the effects of changing precipitation characteristics (rainfall, snow cover and melt) on long-term landscape development were simulated. In the Dinosoaur badlands, weathering and erosion experiments show that the balance between snowmelt induced weathering in the spring, summer rainfall, and erosion determines the rate of slope retreat. In the Zin Valley, on the other hand, the magnitude of the individual rainstorms determines whether a slope section is eroded or acts as a runoff and sediment sink. As a consequence, in the Zin Valley badland slopes experienced an auto-stabilization during the Quaternary. In the Dinosaur Badlands, on the other hand, Holocene climatic variations do not appear to have caused a permanent differentiation of patterns of erosion and deposition. Based on these results the reaction of badland slopes to changing precipitation characteristics was modeled. The model shows that both badland slope systems are currently fairly stable against climate change in the range of variations in rainfall characteristics experienced during the Holocene

  5. Advantages, problems and limitations of different field and laboratory approaches for investigating soil hydrophobicity switching patterns

    NASA Astrophysics Data System (ADS)

    Walsh, R. P. D.; Ferreira, C. S. S.; Urbanek, E.; Shakesby, R. A.; Leighton-Boyce, G.; Doerr, S. H.; Ferreira, A. D. J.; Stoof, C.

    2009-04-01

    This poster presents the research approaches and early results of a programme of field and laboratory investigation to assess three-dimensional patterns of switching of soils between hydrophobic and hydrophilic states. It focuses on soils on terrain of burnt and unburnt eucalyptus, pine and scrub land-use in north-central Portugal. Although much is known about soil hydrophobicity, assessments of the overall hydrological and erosional significance of the soil property in any environmental situation are greatly hampered by a lack of knowledge on switching, mainly because of the destructive nature of methods of measuring the soil property, coupled with the often high local spatial variability of hydrophobicity within soils. In particular little is known about (i) three-dimensional patterns of change (are changes spatially progressive or near-simultaneous within soil profiles and across slopes), (ii) the speed and frequency of switching and (iii) the extent to which the degree of hydrophobicity at particular points change prior to becoming (and with increasing time since being) hydrophilic. Four complementary approaches are being adopted by the research programme reported here. 1) Statistical analysis of differences in the frequency distributions of degree of hydrophobicity of seasonal snapshot surveys of hydrophobicity (surface and subsurface) at four grid networks on unburned and burned eucalyptus terrain in a an area of schist lithology in northern Portugal; (2) A similar statistical analytical approach, but this time focussing on drying sequences provided by daily surveys following individual rainstorms of two grids on unburned and newly burned scrubland; (3) Daily three-dimensional surveys of hydrophobicity around root systems of eucalyptus globules seedlings using excavated pits before and after rainstorms; and (4) laboratory investigation of three-dimensional patterns of hydrophobicity at intervals during simulated wetting and drying phases for a range of

  6. Phase-field investigation on the non-equilibrium interface dynamics of rapid alloy solidification

    SciTech Connect

    Choi, Jeong

    2011-01-01

    The research program reported here is focused on critical issues that represent conspicuous gaps in current understanding of rapid solidification, limiting our ability to predict and control microstructural evolution (i.e. morphological dynamics and microsegregation) at high undercooling, where conditions depart significantly from local equilibrium. More specifically, through careful application of phase-field modeling, using appropriate thin-interface and anti-trapping corrections and addressing important details such as transient effects and a velocity-dependent (i.e. adaptive) numerics, the current analysis provides a reasonable simulation-based picture of non-equilibrium solute partitioning and the corresponding oscillatory dynamics associated with single-phase rapid solidification and show that this method is a suitable means for a self-consistent simulation of transient behavior and operating point selection under rapid growth conditions. Moving beyond the limitations of conventional theoretical/analytical treatments of non-equilibrium solute partitioning, these results serve to substantiate recent experimental findings and analytical treatments for single-phase rapid solidification. The departure from the equilibrium solid concentration at the solid-liquid interface was often observed during rapid solidification, and the energetic associated non-equilibrium solute partitioning has been treated in detail, providing possible ranges of interface concentrations for a given growth condition. Use of these treatments for analytical description of specific single-phase dendritic and cellular operating point selection, however, requires a model for solute partitioning under a given set of growth conditions. Therefore, analytical solute trapping models which describe the chemical partitioning as a function of steady state interface velocities have been developed and widely utilized in most of the theoretical investigations of rapid solidification. However, these

  7. Investigating membrane nanoporation induced by bipolar pulsed electric fields via second harmonic generation

    NASA Astrophysics Data System (ADS)

    Moen, E. K.; Ibey, B. L.; Beier, H. T.; Armani, A. M.

    2016-09-01

    Electric pulses have become an effective tool for transporting cargo (DNA, drugs, etc.) across cell membranes. This enhanced transport is believed to occur through temporary pores formed in the plasma membrane. Traditionally, millisecond duration, monopolar (MP) pulses are used for electroporation, but bipolar (BP) pulses have proven equally effective as MP pulses with the added advantage of less cytotoxicity. With the goal of further reducing cytotoxic effects and inducing non-thermal, intra-cellular effects, researchers began investigating reduced pulse durations, pushing into the nanosecond regime. Cells exposed to these MP, nanosecond pulsed electric fields (nsPEFs) have shown increased repairable membrane permeability and selective channel activation. However, attempts to improve this further by moving to the BP pulse regime has proven unsuccessful. In the present work, we use second harmonic generation imaging to explore the structural effects of bipolar nsPEFs on the plasma membrane. By varying the temporal spacing between the pulse phases over several orders of magnitude and comparing the response to a single MP case, we systematically examine the disparity in cellular response. Our circuit-based model predicts that, as the temporal spacing increases several orders of magnitude, nanoporation increases and eventually exceeds the MP case. On the whole, our experimental data agree with this assertion; however, a detailed analysis of the data sets demonstrates that biological processes may play a larger role in the observed response than previously thought, dominating the effect for temporal spacing up to 5 μs. These findings could ultimately lead to understanding the biophysical mechanism underlying all electroporation.

  8. Fast and simple detection of Yersinia pestis applicable to field investigation of plague foci.

    PubMed

    Simon, Stéphanie; Demeure, Christian; Lamourette, Patricia; Filali, Sofia; Plaisance, Marc; Créminon, Christophe; Volland, Hervé; Carniel, Elisabeth

    2013-01-01

    Yersinia pestis, the plague bacillus, has a rodent-flea-rodent life cycle but can also persist in the environment for various periods of time. There is now a convenient and effective test (F1-dipstick) for the rapid identification of Y. pestis from human patient or rodent samples, but this test cannot be applied to environmental or flea materials because the F1 capsule is mostly produced at 37°C. The plasminogen activator (PLA), a key virulence factor encoded by a Y. pestis-specific plasmid, is synthesized both at 20°C and 37°C, making it a good candidate antigen for environmental detection of Y. pestis by immunological methods. A recombinant PLA protein from Y. pestis synthesized by an Escherichia coli strain was used to produce monoclonal antibodies (mAbs). PLA-specific mAbs devoid of cross-reactions with other homologous proteins were further cloned. A pair of mAbs was selected based on its specificity, sensitivity, comprehensiveness, and ability to react with Y. pestis strains grown at different temperatures. These antibodies were used to develop a highly sensitive one-step PLA-enzyme immunoassay (PLA-EIA) and an immunostrip (PLA-dipstick), usable as a rapid test under field conditions. These two PLA-immunometric tests could be valuable, in addition to the F1-disptick, to confirm human plague diagnosis in non-endemic areas (WHO standard case definition). They have the supplementary advantage of allowing a rapid and easy detection of Y. pestis in environmental and flea samples, and would therefore be of great value for surveillance and epidemiological investigations of plague foci. Finally, they will be able to detect natural or genetically engineered F1-negative Y. pestis strains in human patients and environmental samples.

  9. Field and laboratory emission cell automation and control system for investigating surface chemistry reactions.

    PubMed

    Flemmer, Michael M; Ham, Jason E; Wells, J R

    2007-01-01

    A novel system [field and laboratory emission cell (FLEC) automation and control system] has been developed to deliver ozone to a surface utilizing the FLEC to simulate indoor surface chemistry. Ozone, humidity, and air flow rate to the surface were continuously monitored using an ultraviolet ozone monitor, humidity, and flow sensors. Data from these sensors were used as feedback for system control to maintain predetermined experimental parameters. The system was used to investigate the chemistry of ozone with alpha-terpineol on a vinyl surface over 72 h. Keeping all other experimental parameters the same, volatile organic compound emissions from the vinyl tile with alpha-terpineol were collected from both zero and 100 ppb (parts per 10(9)) ozone exposures. System stability profiles collected from sensor data indicated experimental parameters were maintained to within a few percent of initial settings. Ozone data from eight experiments at 100 ppb (over 339 h) provided a pooled standard deviation of 1.65 ppb and a 95% tolerance of 3.3 ppb. Humidity data from 17 experiments at 50% relative humidity (over 664 h) provided a pooled standard deviation of 1.38% and a 95% tolerance of 2.77%. Data of the flow rate of air flowing through the FLEC from 14 experiments at 300 ml/min (over 548 h) provided a pooled standard deviation of 3.02 ml/min and a 95% tolerance range of 6.03 ml/min. Initial experimental results yielded long term emissions of ozone/alpha-terpineol reaction products, suggesting that surface chemistry could play an important role in indoor environments.

  10. Field and laboratory emission cell automation and control system for investigating surface chemistry reactions

    NASA Astrophysics Data System (ADS)

    Flemmer, Michael M.; Ham, Jason E.; Wells, J. R.

    2007-01-01

    A novel system [field and laboratory emission cell (FLEC) automation and control system] has been developed to deliver ozone to a surface utilizing the FLEC to simulate indoor surface chemistry. Ozone, humidity, and air flow rate to the surface were continuously monitored using an ultraviolet ozone monitor, humidity, and flow sensors. Data from these sensors were used as feedback for system control to maintain predetermined experimental parameters. The system was used to investigate the chemistry of ozone with α-terpineol on a vinyl surface over 72h. Keeping all other experimental parameters the same, volatile organic compound emissions from the vinyl tile with α-terpineol were collected from both zero and 100ppb(partsper109) ozone exposures. System stability profiles collected from sensor data indicated experimental parameters were maintained to within a few percent of initial settings. Ozone data from eight experiments at 100ppb (over 339h) provided a pooled standard deviation of 1.65ppb and a 95% tolerance of 3.3ppb. Humidity data from 17 experiments at 50% relative humidity (over 664h) provided a pooled standard deviation of 1.38% and a 95% tolerance of 2.77%. Data of the flow rate of air flowing through the FLEC from 14 experiments at 300ml/min (over 548h) provided a pooled standard deviation of 3.02ml/min and a 95% tolerance range of 6.03ml/min. Initial experimental results yielded long term emissions of ozone/α-terpineol reaction products, suggesting that surface chemistry could play an important role in indoor environments.

  11. Experimental investigation of the visual field dependency in the erect and supine positions

    NASA Technical Reports Server (NTRS)

    Lichtenstein, J. H.; Saucer, R. T.

    1972-01-01

    The increasing utilization of simulators in many fields, in addition to aeronautics and space, requires the efficient use of these devices. It seemed that personnel highly influenced by the visual scene would make desirable subjects, particularly for those simulators without sufficient motion cues. In order to evaluate this concept, some measure of the degree of influence of the visual field on the subject in necessary. As part of this undertaking, 37 male and female subjects, including eight test pilots, were tested for their visual field dependency or independency. A version of Witkin's rod and frame apparatus was used for the tests. The results showed that nearly all the test subjects exhibited some degree of field dependency, the degree varying from very high field dependency to nearly zero field dependency in a normal distribution. The results for the test pilots were scattered throughout a range similar to the results for the bulk of male subjects. The few female subjects exhibited a higher field dependency than the male subjects. The male subjects exhibited a greater field dependency in the supine position than in the erect position, whereas the field dependency of the female subjects changed only slightly.

  12. AN INVESTIGATION OF THE NEAR FIELDS ON THE CONICAL EQUIANGULAR SPIRAL ANTENNA

    DTIC Science & Technology

    ANTENNA RADIATION PATTERNS, *CONICAL ANTENNAS, * HELICAL ANTENNAS, ELECTRIC CURRENT, ELECTRIC FIELDS, HELIXES, MATHEMATICAL ANALYSIS, MEASUREMENT, PHASE MEASUREMENT, SPIRAL ANTENNAS, STANDING WAVE RATIOS.

  13. [Investigations on the effect of an electrostatic field free of residual waves on the motility of the mouse (author's transl)].

    PubMed

    Fischer, G

    1977-08-01

    Comparative investigations were carried out concerning the influence on the motility of mice of different electrobioclimatic conditions (electrostatic field with a residual wave component of 1% and a field strength of 4.500 V/m; pure residual wave component: 32 Vs/s, field strength 120 V/m/ss; electrostatic field established by batteries: initial voltage 900 V, field strength 4.500 V/m; shielded from ambient atmospheric electrical fields: damping efficiency at 99%). The Faraday condition represented the control as absolutely objective physical magnitude. All experimental chambers were positioned under Faraday shields. Following a 20 day period of acclimatization to the unaccustomed surroundings for the animals (adaptation period), we established the previously described electrophysical conditions in the cages for a further period of 20 days (experimental period). The lowest values measured during the daily readings were found in the Faraday cage, resp. in the pure electrostatic field, the highest in the DC-field with residual wave component resp. in the residual wave component alone. We draw the following conclusion from the findings: the pure DC-field apparently does not possess those bioclimatologically decisive importance that has been and is being postulated from several sides. Many of the stimtng effects observed and attributed to the electrostatic field are most probably due to the residual wave component resulting from the high-voltage generators employed.

  14. Investigations of a simulated geomagnetic field experienced by the International Space Station on attentional performance.

    PubMed

    Del Seppia, Cristina; Mezzasalma, Lorena; Messerotti, Mauro; Cordelli, Alessandro; Ghione, Sergio

    2009-01-01

    We have previously reported that the exposure to an abnormal magnetic field simulating the one encountered by the International Space Station (ISS) orbiting around the Earth may enhance autonomic response to emotional stimuli. Here we report the results of the second part of that study which tested whether this field also affects cognitive functions. Twenty-four volunteers participated in the study, 12 exposed to the natural geomagnetic field and 12 to the magnetic field encountered by ISS. The test protocol consisted of a set of eight tests chosen from a computerized test battery for the assessment of attentional performance. The duration of exposure was 90 min. No effect of exposure to ISS magnetic field was observed on attentional performance.

  15. Investigation of electron trajectories of an x-ray tube in magnetic fields of MR scanners.

    PubMed

    Wen, Zhifei; Fahrig, Rebecca; Conolly, Steven; Pelc, Norbert J

    2007-06-01

    A hybrid x-ray/MR system combining an x-ray fluoroscopic system and an open-bore magnetic resonance (MR) system offers advantages from both powerful imaging modalities and thus can benefit numerous image-guided interventional procedures. In our hybrid system configurations, the x-ray tube and detector are placed in the MR magnet and therefore experience a strong magnetic field. The electron beam inside the x-ray tube can be deflected by a misaligned magnetic field, which may damage the tube. Understanding the deflection process is crucial to predicting the electron beam deflection and avoiding potential damage to the x-ray tube. For this purpose, the motion of an electron in combined electric (E) and magnetic (B) fields was analyzed theoretically to provide general solutions that can be applied to different geometries. For two specific cases, a slightly misaligned strong field and a perpendicular weak field, computer simulations were performed with a finite-element method program. In addition, experiments were conducted using an open MRI magnet and an inserted electromagnet to quantitatively verify the relationship between the deflections and the field misalignment. In a strong (B > E/c; c: speed of light) and slightly misaligned magnetic field, the deflection in the plane of E and B caused by electrons following the magnetic field lines is the dominant component compared to the deflection in the E X B direction due to the drift of electrons. In a weak magnetic field (B < or = E/c), the main deflection is in the E x B direction and is caused by the perpendicular component of the magnetic field.

  16. Investigation of scaling characteristics for defining design environments due to transient ground winds and near-field, nonlinear acoustic fields

    NASA Technical Reports Server (NTRS)

    Shih, C. C.

    1973-01-01

    In order to establish a foundation of scaling laws for the highly nonlinear waves associated with the launch vehicle, the basic knowledge of the relationships among the paramaters pertinent to the energy dissipation process associated with the propagation of nonlinear pressure waves in thermoviscous media is required. The problem of interest is to experimentally investigate the temporal and spacial velocity profiles of fluid flow in a 3-inch open-end pipe of various lengths, produced by the propagation of nonlinear pressure waves for various diaphragm burst pressures of a pressure wave generator. As a result, temporal and spacial characteristics of wave propagation for a parametric set of nonlinear pressure waves in the pipe containing air under atmospheric conditions were determined. Velocity measurements at five sections along the pipes of up to 210 ft. in length were made with hot-film anemometers for five pressure waves produced by a piston. The piston was derived with diaphragm burst pressures at 20, 40, 60, 80 and 100 psi in the driver chamber of the pressure wave generator.

  17. An investigation into the vector ellipticity of extremely low frequency magnetic fields from appliances in UK homes

    NASA Astrophysics Data System (ADS)

    Ainsbury, Elizabeth A.; Conein, Emma; Henshaw, Denis L.

    2005-07-01

    Elliptically polarized magnetic fields induce higher currents in the body compared with their plane polarized counterparts. This investigation examines the degree of vector ellipticity of extremely low frequency magnetic fields (ELF-MFs) in the home, with regard to the adverse health effects reportedly associated with ELF-MFs, for instance childhood leukaemia. Tri-axial measurements of the magnitude and phase of the 0-3000 Hz magnetic fields, produced by 226 domestic mains-fed appliances of 32 different types, were carried out in 16 homes in Worcestershire in the summer of 2004. Magnetic field strengths were low, with average (RMS) values of 0.03 ± 0.02 µT across all residences. In contrast, background field ellipticities were high, on average 47 ± 11%. Microwave and electric ovens produced the highest ellipticities: mean respective values of 21 ± 21% and 21 ± 17% were observed 20 cm away from these appliances. There was a negative correlation between field strength and field polarization, which we attribute to the higher relative field contribution close to each individual (single-phase) appliance. The measurements demonstrate that domestic magnetic fields are extremely complex and cannot simply be characterized by traditional measurements such as time-weighted average or peak exposure levels. We conclude that ellipticity should become a relevant metric for future epidemiological studies of health and ELF-MF exposure. This work is supported by the charity CHILDREN with LEUKAEMIA, registered charity number 298405.

  18. Computational Investigation of Helical Traveling Wave Tube Transverse RF Field Forces

    NASA Technical Reports Server (NTRS)

    Kory, Carol L.; Dayton, James A.

    1998-01-01

    In a previous study using a fully three-dimensional (3D) helical slow-wave circuit cold- test model it was found, contrary to classical helical circuit analyses, that transverse FF electric fields have significant amplitudes compared with the longitudinal component. The RF fields obtained using this helical cold-test model have been scaled to correspond to those of an actual TWT. At the output of the tube, RF field forces reach 61%, 26% and 132% for radial, azimuthal and longitudinal components, respectively, compared to radial space charge forces indicating the importance of considering them in the design of electron beam focusing.

  19. a Field-Theoretical Investigation of 2-D Coulomb Systems with Short-Range Yukawa Repulsion.

    NASA Astrophysics Data System (ADS)

    Jargocki, Krzysztof Piotr

    The two-dimensional Coulomb gas, consisting of positive and negative charges, is an important system which, on one hand, is equivalent to the vortex sector of the planar X-Y model, and, on the other, to the sine-Gordon field theory. In most treatments the charged particles are assumed to have a repulsive hard core which prevents arbitrarily close approaches. In the present work a new regularization scheme based on a soft short-range Yukawa repulsion between the Coulomb gas particles is presented. This formulation is transcribed into a local sine-Gordon-like field theory involving two Bose fields, one the original massless sine -Gordon field corresponding to the long-range Coulomb interaction and an auxiliary massive field corresponding to the short -range Yukawa repulsion. The resulting Lagrangian is not Hermitian. Using the techniques of functional integration, an effective field theory involving the Coulomb field alone is obtained by integrating out the massive field. The resulting Lagrangian is now Hermitian. Then a generalization of Peierls' inequality is used to make a variational calculation of the ground state energy of the Coulomb system. Unlike in the pure sine-Gordon case the theory has a well-defined ground state energy for (beta)q('2) > 2 (or (beta)c('2) > 8(pi)). A new method is used to derive the Kosterlitz -Thouless renormalization group equations, starting with the original sine-Gordon-like theory. The equations are identical to those found previously by other authors. A wave function renormalization is found to be necessary in addition to the normal ordering discussed by Coleman. A fermionized version of the theory is obtained, using the dictionary provided by Kogut and Susskind, which involves two Fermi fields and an electromagnetic potential. Position -space correlation functions are calculated at the critical point. The effective potential is computed in the one -loop approximation. A nonlinear field theory with derivative couplings is found to

  20. Installation Restoration Program. Remedial investigation report. Site 1. Fire Training Area. Volk Field Air National Guard Base, Camp Douglas, Wi. Volume 1. Final remedial investigation report

    SciTech Connect

    Not Available

    1990-07-01

    Volume 1 of this report covers the Remedial Investigation conducted on Site 1, Fire Training Area at Volk Field Air National Guard Base. The remedial work is described and the testing conducted after remediation to insure all contamination has been removed. The study as conducted under the Air National Guard's Installation Restoration Program. Partial contents include: Meteorology; Hydrology; Soils; Water wells; Groundwater; Borings; Samplings; Chemical contamination; Migration; Decontamination.

  1. N-C isotopic investigation of a zeolite-amended agricultural field

    NASA Astrophysics Data System (ADS)

    Ferretti, Giacomo; Natali, Claudio; Faccini, Barbara; Di Giuseppe, Dario; Bianchini, Gianluca; Coltorti, Massimo

    2016-04-01

    In this study, a C and N isotopic investigation in the soil-plant system of the ZeoLIFE project experimental field have been carried out. Since many years, natural and NH4-enriched zeolites have been used as soil amendant in agricultural context in order to reduce N losses, increase NUE (Nitrogen Use Efficiency) and crop yield. Nevertheless up to now there are no studies that, using the stable isotopes approach, highlighted the interaction between zeolites and plants in agricultural systems. The main aims of this study is to verify if natural zeolites amendment can enhance chemical fertilization efficiency and if N transfer from NH4-enriched zeolites to plants really occurs. Plants grown following traditional cultivation methods (with no zeolite addition) and plants grown on soils amended with natural and NH4-enriched zeolites (the latter obtained after mixing with pig-slurry with a very high 15N) were compared for two cultivation cycles (maize and wheat). As widely known, plants grown under conventional farming systems (use of chemical fertilizers as urea) and plants grown under organic farming can be discriminated by the isotopic signatures of plant tissues. For both years the main results of the study reveals that plants grown on plots amended with natural zeolites generally have their nitrogen isotopic signature more similar to that of the chemical fertilizers employed during the cultivation with respect to the plants cultivated in the non-amended plot. This suggests an enhanced N uptake by the plant from this specific N source with respect to the non-amended plot. On the other hand, plants grown on NH4-enriched zeolites registered a higher 15N, approaching the pig-slurry isotopic signature, confirming that this material can constitute an N pool for plants at least for two cultivation cycles. The distinct agricultural practices seem to be reflected in the plant physiology as recorded by the carbon discrimination factor (13C) which generally increases

  2. Settling Velocity Specific SOC Distribution along Hillslopes - A field investigation in Denmark

    NASA Astrophysics Data System (ADS)

    Kuhn, N. J.; Hu, Y.

    2015-12-01

    The net effects of soil erosion by water, as a sink or source of atmospheric CO2, are decisively affected by the spatial re-distribution and stability of eroded soil organic carbon (SOC). The deposition position of eroded SOC, into terrestrial or aquatic systems, is actually decided by the transport distances of soil fractions where the SOC is stored. In theory, the transport distances of aggregated soil fractions are related to their settling velocities under given layer conditions. Yet, little field investigation has been conducted to examine the actual movement of eroded soil fractions along hillslopes, let alone the re-distribution pattern of functional SOC fractions. Eroding sandy soils and sediment were sampled after a series of rainfall events from different topographic positions along a slope on a freshly seeded cropland in Jutland, Denmark. All the soil samples from difference topographic positions along the slope were fractionated into five settling classes using a settling tube apparatus. The SOC content, 13C signature, and C:N ratios of all settling fractions were measured. Our results show that: 1) the spatial distribution of soil settling classes along the slope clearly shows a coarsening effect at the deposition area immediately below the eroding slope, followed by a fining trend on the deposition area at the slope tail. This proves the validity of the conceptual model in Starr et al. 2000 to predict SOC redistribution patterns along eroding hillslopes. 2) The isotopically enriched 13C on the slope back suggests greater decomposition rates possibly experienced by eroded SOC during transport, while the pronounced respiration rates at the slope tail indicate a great potential of CO2 emissions after deposition. Overall, our results illustrate that immediate deposition of fast settling soil fractions, and the thus induced preferential deposition of SOC at foot slope and potential CO2 emissions during transport, must be appropriately accounted for in

  3. FITESC - Field Investigation Team for severe earthquakes in Europe and the Mediterranean basin

    NASA Astrophysics Data System (ADS)

    Cecic, I.; Fitesc Preparatory Group

    2003-04-01

    The formation of the Field Investigation Team of the European Seismological Commission (FITESC) was endorsed by a resolution passed at the XXVIII General Assembly of the ESC at Genoa in September 2002. The idea of the team has induced great interest not only among seismologists, but also geologists, civil engineers and insurance companies. FITESC is a multinational and multidisciplinary team of experts that would, in the case of a damaging earthquake in Europe or the Mediterranean basin, go to the epicentral area and collect high-quality seismological data. The objectives of the team are the following: 1) To map the intensity and damage distributions after future large earthquakes in Europe (using EMS-98), principally from a seismological perspective. 2) To assist local institutes in this task, in cases where such help is needed. 3) To gather macroseismic data in a consistent way from earthquake to earthquake, and to make these data generally available. 4) To ensure that such surveys are carried out under the auspices of a permanent international body (ESC) with responsibility to the whole seismological committee (in contrast to the present situation where such missions are responsible only to a few sponsors). The long-term goal would be a database of intensity information for European earthquakes, which would be a valuable resource for seismic risk studies, and for assessing the likely effects of future large earthquakes. These data would be made freely available on the Internet. As the first step the team will start with macroseismic data only, but the idea is to make the scope of the activities wider, as there are several types of data that can be collected in this way. The list of the experts is prepared (in January 2003 there are 62 team members), along with all information necessary to launch the mission in the shortest possible time. A number of possibilities are being explored at the moment in order to provide long-term financial support outside of existing

  4. The investigation of frequency response for the magnetic nanoparticulate assembly induced by time-varied magnetic field

    NASA Astrophysics Data System (ADS)

    Sun, Jianfei; Sui, Yunxia; Wang, Chunyu; Gu, Ning

    2011-07-01

    The field-induced assembly of γ-Fe2O3 nanoparticles under alternating magnetic field of different frequency was investigated. It was found that the assembly was dependent upon the difference between colloidal relaxation time and field period. The same experiments on DMSA-coated γ-Fe2O3 nanoparticles exhibited that the relaxation time may be mainly determined by the magnetic size rather than the physical size. Our results may be valuable for the knowledge of dynamic assembly of colloidal particles.

  5. [Quality assurance at a health center: 2 years' experience].

    PubMed

    Marquet, R; Davins, J; Casas, J; Fernández, R M

    1991-11-01

    In the Primary Care field there is very little experience of organizing a quality control programme that covers all aspects of care. In our centre, at the beginning of 1989, a Quality Control Commission (QCC) was formed with the aim of establishing and coordinating these activities. We describe our two year experience in this report, with special emphasis on the programme's organizational side and the methodological difficulties we encountered while introducing the programme.

  6. Investigation of wing crack formation with a combined phase-field and experimental approach

    NASA Astrophysics Data System (ADS)

    Lee, Sanghyun; Reber, Jacqueline E.; Hayman, Nicholas W.; Wheeler, Mary F.

    2016-08-01

    Fractures that propagate off of weak slip planes are known as wing cracks and often play important roles in both tectonic deformation and fluid flow across reservoir seals. Previous numerical models have produced the basic kinematics of wing crack openings but generally have not been able to capture fracture geometries seen in nature. Here we present both a phase-field modeling approach and a physical experiment using gelatin for a wing crack formation. By treating the fracture surfaces as diffusive zones instead of as discontinuities, the phase-field model does not require consideration of unpredictable rock properties or stress inhomogeneities around crack tips. It is shown by benchmarking the models with physical experiments that the numerical assumptions in the phase-field approach do not affect the final model predictions of wing crack nucleation and growth. With this study, we demonstrate that it is feasible to implement the formation of wing cracks in large scale phase-field reservoir models.

  7. Investigation of the structure of the electromagnetic field and related phenomena, generated by the Active Satellite

    NASA Technical Reports Server (NTRS)

    Alpert, Yakov L.

    1991-01-01

    The altitude dependencies of the moduli of the electric field E in the VLF and LF frequency bands (f sub B much less than F less than f sub B) and in the altitude range of the ionosphere Z equals (400 to 2500) km up to Z equals 6000 km (the bottom of the magnetosphere) were calculated by the linear theory. The amplitudes of the field have large maxima in four regions: the axis field (E sub o) close to the direction of the Earth's magnetic field line B sub o, beta approximately 0 degrees, the fields (E sub St), (E sub RevSt) and (E sub Res) in the Storey, Reversed Story and Resonance cones, beta approximately (0 approaches 20) degrees. Their maxima are very pronounced close to the low hybrid frequency F sub L. The nonlinear heating of the magnetoplasma under the action of an electric field Ee (sup iwt) was recently expanded by the macroscopic theory by the author. The velocities, collision frequencies and temperatures of all the constituents of a magnetoplasma - electrons, ions, and neutral particles - are taken into account. Formulae and numerical results are presented for the ionosphere in the frequency band F equals (1 to 10 exp 4) kHz and altitude range Z approximately (100 - 1000) km. Some results of calculations by the self consistent solution of the basis system of equations are also discussed.

  8. Electric-field response based experimental investigation of unsaturated soil slope seepage

    NASA Astrophysics Data System (ADS)

    Geng, Jishi; Sun, Qiang; Zhang, Yuchun; Yan, Changgen; Zhang, Weiqiang

    2017-03-01

    Rainfall is one of the important factors causing the failure of slope, such as the occurrence of transverse cracks and localized slumps. The process of rainfall seepage was studied with an indoor soil slope model based on the Network Parallel Electrical Method. The responses of geoelectric-field parameters were analyzed to infer the evolution process of rainfall seepage path. The variations of geoelectric-field parameters also contribute to our understanding of the behavior of groundwater seepage. The results show that the seepage velocity and seepage position of groundwater can be obtained according to the exciting current and primary field potential response characteristics of seepage field. The primary field potential, exciting current, spontaneous potential and apparent resistivity are sensitive to the water flow. When the position of the seepage surface reaches a certain electrode, the spontaneous potential, primary field potential and exciting current rapidly increase, while the apparent resistivity decreases gradually. The result of apparent resistivity can reflect the variation of the water content in the 3D structural soil slope and the position of infiltration surface. The results of study can provide the theoretical basis for studying the behavior of moisture flow in soil slope under rainfall condition.

  9. Structural Investigations of Afghanistan Deduced from Remote Sensing and Potential Field Data

    NASA Astrophysics Data System (ADS)

    Saibi, Hakim; Azizi, Masood; Mogren, Saad

    2016-08-01

    This study integrates potential gravity and magnetic field data with remotely sensed images and geological data in an effort to understand the subsurface major geological structures in Afghanistan. Integrated analysis of Landsat SRTM data was applied for extraction of geological lineaments. The potential field data were analyzed using gradient interpretation techniques, such as analytic signal (AS), tilt derivative (TDR), horizontal gradient of the tilt derivative (HG-TDR), Euler Deconvolution (ED) and power spectrum methods, and results were correlated with known geological structures. The analysis of remote sensing data and potential field data reveals the regional geological structural characteristics of Afghanistan. The power spectrum analysis of magnetic and gravity data suggests shallow basement rocks at around 1 to 1.5 km depth. The results of TDR of potential field data are in agreement with the location of the major regional fault structures and also the location of the basins and swells, except in the Helmand region (SW Afghanistan) where many high potential field anomalies are observed and attributed to batholiths and near-surface volcanic rocks intrusions. A high-resolution airborne geophysical survey in the data sparse region of eastern Afghanistan is recommended in order to have a complete image of the potential field anomalies.

  10. Investigation on stresses of superconductors under pulsed magnetic fields based on multiphysics model

    NASA Astrophysics Data System (ADS)

    Yang, Xiaobin; Li, Xiuhong; He, Yafeng; Wang, Xiaojun; Xu, Bo

    2017-04-01

    A multiphysics model for the numerical computation of stresses, trapped field and temperature distribution of a infinite long superconducting cylinder is proposed, based on which the stresses, including the thermal stresses and mechanical stresses due to Lorentz force, and trapped fields in the superconductor subjected to pulsed magnetic fields are analyzed. By comparing the results under pulsed magnetic fields with different pulse durations, it is found that the both the mechanical stress due to the electromagnetic force and the thermal stress due to temperature gradient contribute to the total stress level in the superconductor. For pulsed magnetic field with short durations, the thermal stress is the dominant contribution to the total stress, because the heat generated by AC-loss builds up significant temperature gradient in such short durations. However, for a pulsed field with a long duration the gradient of temperature and flux, as well as the maximal tensile stress, are much smaller. And the results of this paper is meaningful for the design and manufacture of superconducting permanent magnets.

  11. Investigation of recurrent EUV jets from highly dynamic magnetic field region

    NASA Astrophysics Data System (ADS)

    Joshi, Navin Chandra; Chandra, Ramesh; Guo, Yang; Magara, Tetsuya; Zhelyazkov, Ivan; Moon, Young-Jae; Uddin, Wahab

    2017-01-01

    In this work, we present observations and interpretations of recurrent extreme ultraviolet (EUV) jets that occurred between 2012 July 1 21:00 UT and 2012 July 2 10:00 UT from the western edge of the NOAA active region 11513. Solar Dynamics Observatory/Atmospheric Imaging Assembly ( SDO/AIA), SDO/Helioseismic and Magnetic Imager ( SDO/HMI) and Reuven Ramaty High Energy Solar Spectroscopic Imager ( RHESSI) observations have been used for the present study. Observations as well as potential-field source-surface (PFSS) extrapolation suggest an open field configuration in the vicinity of the jet activity area. 18 EUV jets were observed from the western edge of the active region along the open field channel. All the jet events appeared to be non-homologous and show different morphological properties and evolution. Some of the jets were small and narrow in size while the others were huge and wide. The average speed of these jets ranges from {˜}47 to {˜}308 km s^{-1}. SDO/AIA 171 Å intensity profiles at the base of these jets show bumps corresponding to each jet, which is an evidence of recurrent magnetic reconnections. The magnetic field observation at the foot points of the jets revealed a very complex and dynamic magnetic activity which includes flux emergence, flux cancellation, dynamic motions, merging, separation, etc. We suggest that the recurrent jets are the result of recurrent magnetic reconnections among the various emerging bipolar fields themselves as well as with the open fields.

  12. MAGNETIC FIELD CONFIGURATION AT THE GALACTIC CENTER INVESTIGATED BY WIDE-FIELD NEAR-INFRARED POLARIMETRY: TRANSITION FROM A TOROIDAL TO A POLOIDAL MAGNETIC FIELD

    SciTech Connect

    Nishiyama, Shogo; Yoshikawa, Tatsuhito; Nagata, Tetsuya; Hatano, Hirofumi; Nagayama, Takahiro; Tamura, Motohide; Matsunaga, Noriyuki; Suenaga, Takuya; Hough, James H.; Sugitani, Koji; Kato, Daisuke

    2010-10-10

    We present a large-scale view of the magnetic field (MF) in the central 2{sup 0} x 2{sup 0} region of our Galaxy. The polarization of point sources has been measured in the J, H, and K{sub S} bands using the near-infrared polarimetric camera SIRPOL on the 1.4 m Infrared Survey Facility telescope. Comparing the Stokes parameters between high extinction stars and relatively low extinction ones, we obtain polarization originating from magnetically aligned dust grains in the central few hundred parsecs of our Galaxy. We find that near the Galactic plane, the MF is almost parallel to the Galactic plane (i.e., toroidal configuration), but at high Galactic latitudes (|b | >0.{sup 0}4) the field is nearly perpendicular to the plane (i.e., poloidal configuration). This is the first detection of a smooth transition of the large-scale MF configuration in this region.

  13. Tissue engineering with electric fields: investigation of the shape of mammalian cell aggregates formed at interdigitated oppositely castellated electrodes.

    PubMed

    Sebastian, Anil; Venkatesh, Alagarswamy G; Markx, Gerard H

    2007-11-01

    The shape of aggregates of cells formed by positive dielectrophoresis (DEP) at interdigitated oppositely castellated electrodes under different conditions was investigated and compared with calculations of the electric field gradient |nablaE(2)|, and the electric field E, and E(2). The results confirm that at low field strength the cells predominantly accumulate above the tips of the electrodes, but at higher electric field strengths the cells predominantly accumulate in the middle of the aggregate. For a given electrode size, a higher applied voltage significantly increases the aggregate footprint. Higher flow rates distort this pattern, with more cells accumulating at the electrodes that are upstream. Calculation of the electric field strength E, E(2) and the electric field strength gradient |nablaE(2)| in the interdigitated oppositely castellated electrode array shows that, at low flow rates, there is a strong correlation between the aggregate shape and the distribution of the electric field E and E(2), but not so between the aggregate shape and |nablaE(2)|. The results indicate that interparticle forces such as pearlchain formation strongly affect the aggregation process, but that, when positive DEP is used to make the aggregates, the distribution of the electric field E, or better E(2), can be used as a useful guide to the final aggregate shape.

  14. [Environmental investigation of ground water contamination at Wright-Patterson Air Force Base, Ohio]. Volume 3, Sampling and analysis plan (SAP): Phase 1, Task 4, Field Investigation: Draft

    SciTech Connect

    Not Available

    1991-10-01

    In April 1990, Wright-Patterson Air Force Base (WPAFB), initiated an investigation to evaluate a potential Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) removal action to prevent, to the extent practicable, the offsite migration of contaminated ground water from WPAFB. WPAFB retained the services of the Environmental Management Operations (EMO) and its principle subcontractor, International Technology Corporation (IT) to complete Phase 1 of the environmental investigation of ground-water contamination at WPAFB. Phase 1 of the investigation involves the short-term evaluation and potential design for a program to remove ground-water contamination that appears to be migrating across the western boundary of Area C, and across the northern boundary of Area B along Springfield Pike. Primarily, Task 4 of Phase 1 focuses on collection of information at the Area C and Springfield Pike boundaries of WPAFB. This Sampling and Analysis Plan (SAP) has been prepared to assist in completion of the Task 4 field investigation and is comprised of the Quality Assurance Project Plan (QAPP) and the Field Sampling Plan (FSP).

  15. [Environmental investigation of ground water contamination at Wright-Patterson Air Force Base, Ohio]. Volume 2, Work plan: Phase 1, Task 4, Field Investigation: Draft

    SciTech Connect

    Not Available

    1991-10-01

    In April 1990 Wright-Patterson Air Force Base (WPAFB) initiated an investigation to evaluate a potential CERCLA removal action to prevent, to the extent practicable, the migration of ground-water contamination in the Mad River Valley Aquifer within and across WPAFB boundaries. The action will be based on a Focused Feasibility Study with an Action Memorandum serving as a decision document that is subject to approval by the Ohio Environmental Protection Agency. The first phase (Phase 1) of this effort involves an investigation of ground-water contamination migrating across the southwest boundary of Area C and across Springfield Pike adjacent to Area B. Task 4 of Phase 1 is a field investigation to collect sufficient additional information to evaluate removal alternatives. The field investigation will provide information in the following specific areas of study: water-level data which will be used to permit calibration of the ground-water flow model to a unique time in history; and ground-water quality data which will be used to characterize the current chemical conditions of ground water.

  16. Investigations of flow field perturbations induced on slotted transonic-tunnel walls

    NASA Technical Reports Server (NTRS)

    Wu, J. M.; Collins, F. G.

    1984-01-01

    The free-stream interference caused by the flow through the slotted walls of the test sections of transonic wind tunnels has continuously a problem in transonic tunnel testing. The adaptive-wall transonic tunnel is designed to actively control the near-wall boundary conditions by sucking or blowing through the wall. In order to make the adaptive-wall concept work, parameters for computational boundary conditions must be known. These parameters must be measured with sufficient accuracy to allow numerical convergence of the flow field computations and must be measured in an inviscid region away from the model that is placed inside the wind tunnel. The near-wall flow field was mapped in detail using a five-port cone probe that was traversed in a plane transverse to the free-stream flow. The initial experiments were made using a single slot and recent measurements used multiple slots, all with the tunnel empty. The projection of the flow field velocity vectors on the transverse plane revealed the presence of a vortex-like flow with vorticity in the free stream. The current research involves the measurement of the flow field above a multislotted system with segmented plenums behind it, in which the flow is controlled through several plenums simultaneously. This system would be used to control a three-dimensional flow field.

  17. Investigation of creating possibilities of multi-channel optical system with discrete angular field

    NASA Astrophysics Data System (ADS)

    Repin, Vladislav A.; Gorbunova, Elena V.; Chertov, Aleksandr N.

    2016-04-01

    Often, in practice, there is a problem of large areas of space viewing in order to fix certain parameters of moving objects. A multichannel optical-electronic monitoring system with a discrete angular field (or, as they say, artificial compound eye system) is an interesting variant to solve this problem. Such systems can be used for the analysis of various parameters of the objects, as an example for positioning of the object in wide annular zone. Using these systems we can get a wide angular field up to the full sphere due to a combination of a large number of elementary light detecting channels (like compound eyes of insects) and have a gain in the useful signal due to overlapping angular fields of channels. Currently, multichannel optoelectronic systems with discrete angular field are described and studied less than other up-to-date monitoring devices. But existing analogues are presented by experimental samples, which demonstrate the relevance of the research and design of such devices. This work presents a brief review of monitoring system with discrete angular field and theoretical description of proposed prototype. Results of experimental studies of mentioned prototype are presented as well.

  18. A numerical investigation of the interaction between convection and magnetic field in a solar surface layer

    NASA Astrophysics Data System (ADS)

    Bercik, David John

    2002-11-01

    Three-dimensional numerical simulations are used to study the dynamic interaction between magnetic fields and convective motions near the solar surface. The magnetic field is found to be transported by convective motions from granules to the intergranular lanes, where it collects and is compressed. A convective instability causes the upper levels of magnetic regions to be evacuated, compressing the field beyond equipartition values, and forming “flux tubes” or “flux sheets”. The degree to which the field is compressed controls how much convective transport is suppressed within the flux structure, and ultimately determines whether the magnetic feature appears brighter or darker than its surroundings. For this reason, the continuum intensity is not a good tracer of the lifetimes of magnetic features, since their bright/dark signature is transient in nature. Larger magnetic structures form at sites where a granule submerges and the surrounding field is pushed into the resulting dark hole. These micropores are devoid of flow in their interior and cool by radiating radially. The convective downflows that collar the micropore heat its edges by lateral radiation, but fail to penetrate far enough into the interior to prevent an overall cooling, and therefore darkening, of the micropore. Magnetic features undergo numerous mergers or splittings during their lifetimes as a result of being pushed and squeezed by the expansion of adjacent granules. Larger structures survive for several convective turnover times, but smaller structures are too weak to resist convective motions, and are destroyed on a convective time scale.

  19. The efficacy of the Rio Hondo DUI court: a 2-year field experiment.

    PubMed

    MacDonald, John M; Morral, Andrew R; Raymond, Barbara; Eibner, Christine

    2007-02-01

    This study reports results from an evaluation of the experimental Rio Hondo driving under the influence (DUI) court of Los Angeles County, California. Interviews and official record checks with 284 research participants who were randomly assigned to a DUI court or a traditional criminal court were assessed at baseline and at 24-month follow-up. The interviews assessed the impact of the DUI court on self-reported drunk driving behavior, the completion of treatment, time spent in jail, alcohol use, and stressful life events. Official record checks assessed the impact of the DUI court on subsequent arrests for driving under the influence and other drinking-related behaviors. Few differences on any outcomes were observed between participants in the experimental DUI court and those assigned to the traditional court. The results suggest that the DUI court model had little additional therapeutic or public safety benefit over the traditional court process. The implication of these findings for the popularity of specialized courts for treating social problems is discussed.

  20. The Efficacy of the Rio Hondo Dui Court: A 2-Year Field Experiment

    ERIC Educational Resources Information Center

    MacDonald, John M.; Morral, Andrew R.; Raymond, Barbara; Eibner, Christine

    2007-01-01

    This study reports results from an evaluation of the experimental Rio Hondo driving under the influence (DUI) court of Los Angeles County, California. Interviews and official record checks with 284 research participants who were randomly assigned to a DUI court or a traditional criminal court were assessed at baseline and at 24-month follow-up.…

  1. Remediation of a watershed contaminated by heavy metals: a 2-year field biomonitoring of periphytic biofilms.

    PubMed

    Arini, Adeline; Feurtet-Mazel, Agnès; Morin, Soizic; Maury-Brachet, Régine; Coste, Michel; Delmas, François

    2012-05-15

    This study focuses on an industrial contamination site subjected to remediation processes since 2007 in the Riou-Mort watershed (southwest France). The purpose was to assess the first impacts of remediation on periphytic biofilms, and was performed during two years of biomonitoring. Periphytic biofilms were collected on glass slides immersed 24 days at different sites along the contamination gradient for 12 colonisation cycles. Metal contaminations (Cd and Zn) were analysed in biofilms and the evolution of diatom communities was assessed, integrating teratology quantifications. Despite remediation work initiated at the industrial site, this study demonstrated the persistence of metal contamination in water, as well as in biofilms. In addition, our data, showed that the remediation process was initially marked by an increase in metal contamination in the river, with increasing diatom community shifts. Metal-contaminated biofilms presented decreasing species diversities and were dominated by metal-resistant species such as Eolimna minima, whom abundances increased in 2010 reaching 57.2±10%. No significant decrease in metal accumulation was observed and total Cd content in biofilms collected downstream the industrial site ranged from 772.7±88 in July 2009 to 636.9±20 μg/gDW in July 2010. Results obtained on artificial substrates were compared with those of natural substrates and showed similar diatom communities and abundances of deformed diatoms but lower diversities. This ensured that glass slide subtrates gave a good representation of periphytic biofilm health. Finally, results were compared to studies performed before the remediation process and this did not reveal a decrease of metal accumulation in biofilms nor shifts in taxonomic composition of the communities, rather the remaining dominance of metal resistant species such as E. minima was confirmed.

  2. Simulation investigation of a Ku-band radial line oscillator operating at low guiding magnetic field

    SciTech Connect

    Dang, Fangchao Zhang, Xiaoping; Zhong, Huihuang; Li, Yangmei; Qi, Zumin

    2014-06-15

    A novel radial line oscillator operating at Ku-band with low guiding magnetic field is proposed in this paper. By using an oversized radial structure, the power handling capacity is enhanced significantly. Based on the small-signal theory, the π/2 mode in radial TM{sub 01} mode is selected as the working mode. Furthermore, a radial uniform guiding magnetic field, made up of four solenoids, is designed. As indicated in 2.5-dimensional fully electromagnetic particle-in-cell simulation, high power microwaves with a power of 2.2 GW and a frequency of 14.25 GHz are generated with over 40% efficiency when the electron beam voltage is 300 kV, the beam current 18 kA, and the guiding magnetic field is only 0.6 T. There is no angular non-asymmetric mode discovered in three-dimensional simulation.

  3. Geometrical investigation of the kinetic evolution of the magnetic field in a periodic flux rope

    SciTech Connect

    Restante, A. L.; Lapenta, G.; Markidis, S.; Intrator, T.

    2013-08-15

    Flux ropes are bundles of magnetic field wrapped around an axis. Many laboratory, space, and astrophysics processes can be represented using this idealized concept. Here, a massively parallel 3D kinetic simulation of a periodic flux rope undergoing the kink instability is studied. The focus is on the topology of the magnetic field and its geometric structures. The analysis considers various techniques such as Poincaré maps and the quasi-separatrix layer (QSL). These are used to highlight regions with expansion or compression and changes in the connectivity of magnetic field lines and consequently to outline regions where heating and current may be generated due to magnetic reconnection. The present study is, to our knowledge, the first QSL analysis of a fully kinetic 3D particle in cell simulation and focuses the existing QSL method of analysis to periodic systems.

  4. Impact-generated magnetic fields on the Moon : a magnetohydrodynamic numerical investigation

    NASA Astrophysics Data System (ADS)

    Oran, Rona; Shprits, Yuri; Weiss, Benjamin; Gombosi, Tamas

    2015-04-01

    Natural remanent magnetization has been identified in lunar rocks, the lunar crust, and a diversity of meteorites. Much of this magnetization is thought to have been produced by cooling a core dynamo mag-netic field. However, the identification of lunar crustal magnetic anomalies at the antipodes of four of the five youngest large (>600 km diameter) impact basins has motivated the alternative hypothesis that the lunar crust could have been magnetized by the impacts. In particular, it has been proposed that highly conducting ionized vapor produced by a basin-forming impact interacts with the ambient solar wind plasma surrounding the Moon to amplify the ambient solar wind magnetic field or any core dynamo field. In this picture, as the ionized vapor cloud expands around the Moon, it pushes and compresses the solar wind plasma into a small region at the antipodal point. The conservation of magnetic flux then leads to an enhanced magnetic field in the compressed plasma. This field can then be recorded as shock remanent magnetization by crustal materials at the antipodal point following the impact of converging basin ejecta. A key requirement for the impact-generated fields hypothesis is that the compressed field be suffi-ciently strong to explain the lunar paleointensities (at least tens of μT) and maintained at the antipodal point for a sufficiently long time (several hours) for the ejecta to arrive and impact the surface. Previous simulations of the expansion of the vapor cloud found that the enhanced field will be strong enough (per-haps reaching hundreds of μT) and will remain at the antipodal site for a sufficiently long time (>1 day) for the arrival of incoming ejecta. However, these studies did not include an explicit calculation of the interaction of the magnetized solar wind plasma with the vapor cloud. Rather, the cloud evolution under the lunar gravity was simulated in the purely hydrodynamic regime. The vapor cloud structure at certain times was used to

  5. An experimental investigation of circulation control flow fields using holographic interferometry

    NASA Technical Reports Server (NTRS)

    Bachalo, William D.

    1982-01-01

    Experiments are presented which were conducted on flow fields produced by a circulation control airfoil utilizing the Coanda effect at the trailing edge. The application of holographic interferometry to obtain both visualization and quantitative data on the flow field about a circulation control airfoil at transonic flow speed is covered. A brief description of the flow model and measurement techniques is given. The data reduction procedure, results, and interpretation are presented. The results have provided a good deal of information on the character of the flow field, particularly in the neighborhood of the trailing edge. As to the airfoil design, it is apparent that improved performance can be achieved if jet detachment is delayed. Another design improvement would involve the development of an optimum trailing-edge shape for the expected operating Mach and Reynolds number ranges.

  6. Simulation investigation of a Ku-band radial line oscillator operating at low guiding magnetic field

    NASA Astrophysics Data System (ADS)

    Dang, Fangchao; Zhang, Xiaoping; Zhong, Huihuang; Li, Yangmei; Qi, Zumin

    2014-06-01

    A novel radial line oscillator operating at Ku-band with low guiding magnetic field is proposed in this paper. By using an oversized radial structure, the power handling capacity is enhanced significantly. Based on the small-signal theory, the π/2 mode in radial TM01 mode is selected as the working mode. Furthermore, a radial uniform guiding magnetic field, made up of four solenoids, is designed. As indicated in 2.5-dimensional fully electromagnetic particle-in-cell simulation, high power microwaves with a power of 2.2 GW and a frequency of 14.25 GHz are generated with over 40% efficiency when the electron beam voltage is 300 kV, the beam current 18 kA, and the guiding magnetic field is only 0.6 T. There is no angular non-asymmetric mode discovered in three-dimensional simulation.

  7. Investigation on Sound Field Model of Propeller AIRCRAFT—THE Effect of Rigid Fuselage Boundary

    NASA Astrophysics Data System (ADS)

    Wang, T. Q.; Zhou, S.

    1998-01-01

    An improved sound field model with multiple propeller noise sources and finite fuselage boundary has been developed for the prediction of propeller aircraft noise by using the acoustic analogy method. It involves the effects of fuselage boundary with arbitrary shape and coupling of multiple propeller sources. It is also applicable to solving the interaction between any known boundary and harmonic sound source. The model has been used to calculate the sound field of propeller aircraft Y12 with rigid fuselage boundary and the sound field of rigid sphere in planar harmonic sound wave. The latter has an analytical solution which could be used to check the present method. The calculation results show that the model is reasonable and valuable.

  8. Field Investigation of the Turbulent Flux Parameterization and Scalar Turbulence Structure over a Melting Valley Glacier

    NASA Astrophysics Data System (ADS)

    Guo, X.; Yang, K.; Yang, W.; Li, S.; Long, Z.

    2011-12-01

    We present a field investigation over a melting valley glacier on the Tibetan Plateau. One particular aspect lies in that three melt phases are distinguished during the glacier's ablation season, which enables us to compare results over snow, bare-ice, and hummocky surfaces [with aerodynamic roughness lengths (z0M) varying on the order of 10-4-10-2 m]. We address two issues of common concern in the study of glacio-meteorology and micrometeorology. First, we study turbulent energy flux estimation through a critical evaluation of three parameterizations of the scalar roughness lengths (z0T for temperature and z0q for humidity), viz. key factors for the accurate estimation of sensible heat and latent heat fluxes using the bulk aerodynamic method. The first approach (Andreas 1987, Boundary-Layer Meteorol 38:159-184) is based on surface-renewal models and has been very widely applied in glaciated areas; the second (Yang et al. 2002, Q J Roy Meteorol Soc 128:2073-2087) has never received application over an ice/snow surface, despite its validity in arid regions; the third approach (Smeets and van den Broeke 2008, Boundary-Layer Meteorol 128:339-355) is proposed for use specifically over rough ice defined as z0M > 10-3 m or so. This empirical z0M threshold value is deemed of general relevance to glaciated areas (e.g. ice sheet/cap and valley/outlet glaciers), above which the first approach gives underestimated z0T and z0q. The first and the third approaches tend to underestimate and overestimate turbulent heat/moisture exchange, respectively (relative errors often > 30%). Overall, the second approach produces fairly low errors in energy flux estimates; it thus emerges as a practically useful choice to parameterize z0T and z0q over an ice/snow surface. Our evaluation of z0T and z0q parameterizations hopefully serves as a useful source of reference for physically based modeling of land-ice surface energy budget and mass balance. Second, we explore how scalar turbulence

  9. The 2007 Pisco earthquake (Mw=8.0), Central Peru: Preliminary Field Investigations and Seismotectonic Context

    NASA Astrophysics Data System (ADS)

    Audin, L.; Perfettini, H.; Avouac, J.; Farber, D.; de La Cruz, D.; Chlieh, M.

    2007-12-01

    This epicentral area of the 2007 Pisco earthquake marks a major transition in the characteristics of the Nazca subduction zone: 1) the megathrust dip angle is shallower (15-20) to the north than to the south (25-30); 2) megathrust earthquakes have distinctly smaller magnitudes and are more fragmented to the north; 3) the distance between the trench and the coastline changes abruptly from ~180km to the north to ~80km to the south. These variations are likely related to the oblique subduction of the Nazca ridge - a major bathymetric high - beneath the continental margin. The effect of the subduction of the ridge is obvious in the morphology and tectonics of the forearc, in particular, around the Paracas Peninsula where late Pliocene marine formations are uplifted and the forearc tectonic regime changes from compression to extension. The geometry of the coastline reflects the sweeping of ridge beneath the margin. The coastline also seems to relate to the mode of slip along the subduction interface: modeling of the available interseismic GPS data shows that the plate interface was locked at depth shallower than about 50km, with the downdip end of the Locked Fault Zone (LFZ) corresponding approximately to the coastline. However, the resolution of GPS data is not sufficient to test the idea that the coastline morphology mirrors in detail the variation of the downdip edge of the LFZ. We investigated evidence for uplift or subsidence along the coast and found that the coastline didn't experience any significant vertical displacement compared to the tide range (~40cm). The coastline approximately corresponds to a pivot line marking the transition from coastal uplift in the south to subsidence in the north, as the distance from the trench increases. This model is consistent with the co-seismic slip distribution inferred from waveform modeling, and with the distribution of aftershocks which suggests that the subduction interface ruptured mainly updip of the coastline. To

  10. The 2007 Pisco earthquake (Mw=8.0), Central Peru: Preliminary Field Investigations and Seismotectonic Context

    NASA Astrophysics Data System (ADS)

    Audin, L.; Perfettini, H.; Avouac, J.; Farber, D.; de La Cruz, D.; Chlieh, M.

    2004-12-01

    This epicentral area of the 2007 Pisco earthquake marks a major transition in the characteristics of the Nazca subduction zone: 1) the megathrust dip angle is shallower (15-20) to the north than to the south (25-30); 2) megathrust earthquakes have distinctly smaller magnitudes and are more fragmented to the north; 3) the distance between the trench and the coastline changes abruptly from ~180km to the north to ~80km to the south. These variations are likely related to the oblique subduction of the Nazca ridge - a major bathymetric high - beneath the continental margin. The effect of the subduction of the ridge is obvious in the morphology and tectonics of the forearc, in particular, around the Paracas Peninsula where late Pliocene marine formations are uplifted and the forearc tectonic regime changes from compression to extension. The geometry of the coastline reflects the sweeping of ridge beneath the margin. The coastline also seems to relate to the mode of slip along the subduction interface: modeling of the available interseismic GPS data shows that the plate interface was locked at depth shallower than about 50km, with the downdip end of the Locked Fault Zone (LFZ) corresponding approximately to the coastline. However, the resolution of GPS data is not sufficient to test the idea that the coastline morphology mirrors in detail the variation of the downdip edge of the LFZ. We investigated evidence for uplift or subsidence along the coast and found that the coastline didn't experience any significant vertical displacement compared to the tide range (~40cm). The coastline approximately corresponds to a pivot line marking the transition from coastal uplift in the south to subsidence in the north, as the distance from the trench increases. This model is consistent with the co-seismic slip distribution inferred from waveform modeling, and with the distribution of aftershocks which suggests that the subduction interface ruptured mainly updip of the coastline. To

  11. Investigation of the photodetached electronic wave packet dynamics in a magnetic field near a surface

    NASA Astrophysics Data System (ADS)

    Chen, Zhaohang; Wang, Dehua; Cheng, Shaohao

    2017-01-01

    The electronic wave packet dynamics photodetached from H- ion in a magnetic field near an elastic surface has been studied by using the time-dependent perturbation theory combined with the semiclassical closed orbit theory for the first time. Firstly, we put forward an analytic formula for calculating the autocorrelation function of this system. Then we calculate and analyze the autocorrelation function in great detail. It is demonstrated that the quantum wave packet revival phenomenon is significant when the laser pulse width is far less than the period of the detached electron's closed orbit. As the pulse width is close to the period of the detached electron's closed orbit, the quantum wave packet revival phenomenon becomes weakened. When the laser pulse width is bigger than the period of the closed orbit of the detached electron, the adjacent revival peaks in the autocorrelation function begin to merge and the quantum revival phenomenon disappears. In addition, the magnetic field strength can also affect the autocorrelation function of this system. As the magnetic field strength is relatively small, the quantum wave packet revival phenomenon is weak. With the increase of the magnetic field strength, the number of the reviving peaks in the autocorrelation function becomes increased and the quantum wave packet revival phenomenon becomes significant. Therefore, we can control the quantum wave packet revival in the autocorrelation function of this system by changing the laser pulse width and the external magnetic field strength. This study can guide the future experimental research on the wave packet dynamics of atoms or ions in the external fields or surfaces.

  12. Determining the Intrinsic Permeability of Frazil of Frazil Ice. Part 2. Field Investigations

    DTIC Science & Technology

    1992-05-01

    Nielsen, D.R., J.W. Biggar and K.T. Erh (1973) Spatial McGraw-Hill Book Company. variability of field-measured soil-water properties. Hil- Beltaos , S ...deposits. Beltaos and Dean (1981) conducted further field in- In borehole dilution tests, the dilution of a tracer vestigations which included...Regression 0 400 800 1200 1600 2000 Figure 4. Example showing choice of regression Time ( s ) line (borehole number 8, zone 1). oping the slope (-8v/nd

  13. Hydrogeochemical investigations in support of well logging operations at the Zunil geothermal field, Guatemala

    SciTech Connect

    Adams, A.; Golf, F.; Trujillo, P.E. Jr.; Counce, D.; Archuleta, J.; Dennis, B. ); Medina, V. . Inst. Nacional de Electrificacion)

    1990-01-01

    A suite of 41 thermal and nonthermal waters in the Zunil-Quetzaltenango region, Guatemala, were collected as part of a well logging operation conducted by the Instituto Nacional de Electrificacion (INDE) and Los Alamos National Laboratory. Both in situ and weirbox samples were collected in the Zunil geothermal field. The various data suggest that the reservoir at Zunil is geochemically inhomogeneous. Stable isotope data suggest recharge to the field comes primarily from the north and east whereas tritium data indicate that the reservoir waters may be 500 to 7500 years old. 14 refs., 4 figs., 3 tabs.

  14. Clinically Significant Behavior Problems among Young Children 2 Years after the Great East Japan Earthquake

    PubMed Central

    Fujiwara, Takeo; Yagi, Junko; Homma, Hiroaki; Mashiko, Hirobumi; Nagao, Keizo; Okuyama, Makiko

    2014-01-01

    Background On March 11, 2011, a massive undersea earthquake and tsunami struck East Japan. Few studies have investigated the impact of exposure to a natural disaster on preschool children. We investigated the association of trauma experiences during the Great East Japan Earthquake on clinically significant behavior problems among preschool children 2 years after the earthquake. Method Participants were children who were exposed to the 2011 disaster at preschool age (affected area, n = 178; unaffected area, n = 82). Data were collected from September 2012 to June 2013 (around 2 years after the earthquake), thus participants were aged 5 to 8 years when assessed. Severe trauma exposures related to the earthquake (e.g., loss of family members) were assessed by interview, and trauma events in the physical environment related to the earthquake (e.g. housing damage), and other trauma exposure before the earthquake, were assessed by questionnaire. Behavior problems were assessed by caregivers using the Child Behavior Checklist (CBCL), which encompasses internalizing, externalizing, and total problems. Children who exceeded clinical cut-off of the CBCL were defined as having clinically significant behavior problems. Results Rates of internalizing, externalizing, and total problems in the affected area were 27.7%, 21.2%, and 25.9%, respectively. The rate ratio suggests that children who lost distant relatives or friends were 2.36 times more likely to have internalizing behavior problems (47.6% vs. 20.2%, 95% CI: 1.10–5.07). Other trauma experiences before the earthquake also showed significant positive association with internalizing, externalizing, and total behavior problems, which were not observed in the unaffected area. Conclusions One in four children still had behavior problems even 2 years after the Great East Japan Earthquake. Children who had other trauma experiences before the earthquake were more likely to have behavior problems. These data will be

  15. Physics Laboratory Investigation of Vocational High School Field Stone and Concrete Construction Techniques in the Central Java Province (Indonesia)

    ERIC Educational Resources Information Center

    Purwandari, Ristiana Dyah

    2015-01-01

    The investigation aims in this study were to uncover the observations of infrastructures and physics laboratory in vocational high school for Stone and Concrete Construction Techniques Expertise Field or Teknik Konstruksi Batu dan Beton (TKBB)'s in Purwokerto Central Java Province, mapping the Vocational High School or Sekolah Menengah Kejuruan…

  16. SUPERFUND TREATABILITY CLEARINGHOUSE: SUMMARY REPORT ON THE FIELD INVESTIGATION OF THE SAPP BATTERY SITE JACKSON COUNTY, FLORIDA

    EPA Science Inventory

    This treatability study presents the results of field investigations at the Sapp Battery site in Florida, an abandoned battery recycling operation. The site is estimated to contain 14,300 cubic yards of soils with lead levels in excess of 1,000 ppm. The soils in the immediate v...

  17. Field Summary Report for Remedial Investigation of Hanford Site Releases to the Columbia River, Hanford Site, Washington

    SciTech Connect

    L.C. Hulstrom

    2010-08-11

    This report summarizes field sampling activities conducted in support of WCH’s Remedial Investigation of Hanford Site Releases to the Columbia River. This work was conducted form 2008 through 2010. The work included preliminary mapping and measurement of Hanford Site contaminants in sediment, pore water, and surface water located in areas where groundwater upwelling were found.

  18. Field Summary Report for Remedial Investigation of Hanford Site Releases to the Coumbia River, Hanford Site, Washington

    SciTech Connect

    L.C. Hulstrom

    2010-11-10

    This report summarizes field sampling activities conducted in support of WCH’s Remedial Investigation of Hanford Site Releases to the Columbia River. This work was conducted form 2008 through 2010. The work included preliminary mapping and measurement of Hanford Site contaminants in sediment, pore water, and surface water located in areas where groundwater upwelling were found.

  19. Investigating Perturbation Electric Fields and Their Effects on the Coupled Low-, Mid- and High-latitude Ionosphere

    DTIC Science & Technology

    2015-08-14

    101 nT) allowed us to investigate EIA and SED development taking place in the American sector under varying interplanetary magnetic field ( IMF ...observational evidence we concluded that the underlying plasma-tail reconnection, occurring during northward IMF orientation when daytime

  20. Perthes disease in a 2-year-old child

    PubMed Central

    Dhas, Daphne; Viswanath, Aparna

    2015-01-01

    Perthes disease represents a transient interruption of the blood supply to the femoral head followed by collapse and subsequent remodelling. The majority of cases present between the ages of 4 and 10 years. We report the case of a child who developed a painful right-sided limp some days after his second birthday. The limp was initially interpreted as a transient synovitis of the hip. However, when the limp persisted, further investigations revealed that he had Perthes disease. PMID:25733084

  1. Investigations About the Recording of the Palaeomagnetic Field in the Mono Basin, CA, in Siltstone from a Granitic Provenance

    NASA Astrophysics Data System (ADS)

    Liddicoat, Joseph; Coe, Robert

    2014-05-01

    For more than three decades, Reidar Lovlie did innovative laboratory and field experiments that advanced our understanding about how sediments acquire a remanent magnetization (Lovlie, 1979, and his subsequent publications about that research). The investigations we and our students have done with lacustrine sediments deposited during the late Pleistocene in the Mono Basin, CA, have benefited from those experiments. One of Lovlie's laboratory experiments that was especially useful in our investigation of the role of relative field intensity (RFI) during a rapidly changing field, the Mono Lake Excursion (MLE; Coe and Liddicoat, 1994), was his study of suspended magnetic grains in slowly curing epoxy resin as the field strength was varied (Lovlie, 1993). More recently we did comparative field and laboratory experiments with sediments from different depositional environments in the Mono Basin that help to explain the recording of the palaeomagnetic field in unweathered siltstone derived from a granitic provenance in the California Sierra Nevada. Our investigations are possible because inclination, declination, and RFI using alternating field and thermal demagnetization and intensity normalizing experiments of magnetic susceptibility (k), saturation isothermal remanent magnetization (SIRM), and anhysteretic remanent magnetization (ARM)(Lund et al., 2005) can be measured with precision for localities separated by as much as 15 kilometres using volcanic ash beds as marker horizons. In addition to making the comparison between localities in the Mono Basin that record the MLE, we have done that for a time interval following the MLE also in the Mono Basin where the palaeomagnetic directions are anomalous compared to secular variation (waveform Delta in Lund et al., 1988; Liddicoat and Coe, 2013). In that interval the RFI is nearly double the RFI during the MLE (Zimmerman et al., 2006), which again allows us to study RFI as a factor in the palaeomagnetic recording process in

  2. Experimental and Theoretical Investigations of Flow Fields and Heat Transfer in Modern Gas Turbines.

    DTIC Science & Technology

    1981-12-31

    34 NASA CR-2729, July 1977. 2 Thompson, J.F., Thames, F.C. and Mastin, C.W., "TOMCAT-- A Code for Numerical Generation of Boundary Fitted Curvilinear Coordinate Systems on Fields Containing Any Number of Arbitrary Two - Dimensional Bodies ." J

  3. Field Investigation and Research Reports. The Education of American Indians, October 1969, Volume 2.

    ERIC Educational Resources Information Center

    Congress of the U.S., Washington, DC. Senate Committee on Labor and Public Welfare.

    In the survey of American Indian Education carried out by the special senatorial subcommittee on Indian education, the attempt was to set a pattern for hearings that would provide representative coverage of the problems in the geographical areas concerned. To supplement these hearings, the staff was instructed to make detailed field studies…

  4. Integrated Laboratory and Field Investigations: Assessing Contaminant Risk to American Badgers

    EPA Science Inventory

    This manuscript provides an example of integrated laboratory and field approach to complete a toxicological ecological risk assessment at the landscape level. The core findings from the study demonstrate how radio telemetry data can allow for ranking the relative risks of contam...

  5. Investigating the Impact of Field Trips on Teachers' Mathematical Problem Posing

    ERIC Educational Resources Information Center

    Courtney, Scott A.; Caniglia, Joanne; Singh, Rashmi

    2014-01-01

    This study examines the impact of field trip experiences on teachers' mathematical problem posing. Teachers from a large urban public school system in the Midwest participated in a professional development program that incorporated experiential learning with mathematical problem formulation experiences. During 2 weeks of summer 2011, 68 teachers…

  6. An Investigation into the Contents and Aspects of College Students' Reflective Thoughts during Field Experience

    ERIC Educational Resources Information Center

    Su, Yuling

    2015-01-01

    Field experience makes a strong contribution to the learning of students. However, the procedure for conducting training sessions based on experiential teaching methods is relatively unclear, and the contents and aspects of students' reflections during such training are not well known. This study applied experiential teaching methods in a college…

  7. “Pheromonal Investigations of Green Lacewings (Neuroptera: Chrysopidae: Chrysopa spp.) in the Field and Laboratory”

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field-collected male goldeneyed lacewings, Chrysopa oculata, release (1R,2S,5R,8R)-iridodial but, laboratory-reared C. oculata males did not produce iridodial, despite their healthy appearance and apparently normal fertility. Previous research showed that C. oculata males enter traps baited with iri...

  8. How to Make a Field Trip a Hands-On Investigative Laboratory: Learning about Marine Invertebrates

    ERIC Educational Resources Information Center

    Burrowes, Patricia A.

    2007-01-01

    Research has shown that when students are given the opportunity to ask their own questions and design their own experiments, they become more interested in learning the answers. In this article, the author describes an effective method to do a field trip to the beach and gets her students to make observations about marine animals, come up with a…

  9. A Longitudinal Field Investigation of the Impact of Group Composition on Group Performance and Cohesion.

    ERIC Educational Resources Information Center

    Terborg, James R.; And Others

    In a longitudinal field experiment, 42 groups were assembled on the factors of individual ability and attitude similarity resulting in a 2 x 2 crossed ANOVA design. These groups then worked on six projects which spanned a three-month time period. For each project, measures of group performance and group cohesion were taken. Analyses showed that…

  10. Investigating of the Field Emission Performance on Nano-Apex Carbon Fiber and Tungsten Tips

    NASA Astrophysics Data System (ADS)

    Mousa, Marwan S.; Alnawasreh, Shadi; Madanat, Mazen A.; Al-Rabadi, Anas N.

    2015-10-01

    Field electron emission measurements have been performed on carbon-based and tungsten microemitters. Several samples of both types of emitters with different apex radii have been obtained employing electrolytic etching techniques using sodium hydroxide (NaOH) solution with different molarities depending on the material used. A suitable, home-built, field electron microscope (FEM) with 10 mm tip to screen separation distance was used to electrically characterize the electron emitters. Measurements were carried out under ultra high vacuum (UHV) conditions with base pressure of 10-9 mbar. The current-voltage characteristics (I-V) presented as Fowler-Nordheim (FN) type plots, and field electron emission images have been recorded. In this work, initial comparison of the field electron emission performance of these micro and nanoemitters has been carried out, with the aim of obtaining a reliable, stable and long life powerful electron source. We compare the apex radii measured from the micrographs obtained from the SEM images to those extracted from the FN-type _I-V_plots for carbon fibers and tungsten tips.

  11. Inferring plasma flow velocities from photospheric vector magnetic field observations for the investigation of flare onsets

    NASA Astrophysics Data System (ADS)

    Santos, J. C.; Büchner, J.; Zhang, H.

    2008-09-01

    The amount of emergence and submergence of magnetized plasma and the horizontal motion of the footpoints of flux tubes might be crucial for the dynamics of the solar atmosphere. Although the rate of flux emergence and submergence can be observationally determined near the polarity inversion line (Chae et al., 2004), the same is not true for regions away from the PIL. Also, the horizontal motions cannot be directly measured in the solar photosphere. In this sense, the evolution of the photospheric magnetic field provides valuable information which can be used to estimate photospheric plasma flows since magnetic field and plasma are closely associated (frozen-in-condition). We used three methods to estimate the photospheric plasma motion from magnetic field observations. The methods were applied to photospheric vector magnetic field data of active region NOAA 9077, observed by the Huairou Solar Observing Station (HSOS) of the National Astronomical Observatories of China before and after the ‘Bastille Day’ flare on July 13th and 14th, 2000.

  12. Investigation of exposure to Extremely Low Frequency (ELF) magnetic and electric fields: Ongoing animal studies

    SciTech Connect

    Anderson, L.E.

    1994-03-01

    There is now convincing evidence from a large number of laboratories, that exposure to extremely low frequency (ELF) magnetic and electric fields produces biological responses in animals. Many of the observed effects appear to be directly or indirectly associated with the neural or neuroendocrine systems. Such effects include increased neuronal excitability, chemical and hormonal changes in the nervous system, altered behavioral responses, some of which are related to sensing the presence of the field, and changes in endogenous biological rhythms. Additional indices of general physiological status appear relatively unaffected by exposure, although effects have occasionally been described in bone growth and fracture repair, reproduction and development, and immune system function. A major current emphasis in laboratory research is to determine whether or not the reported epidemiological studies that suggest an association between EMF exposure and risk of cancer are supported in studies using animal models. Three major challenges exist for ongoing research: (1) knowledge about the mechanisms underlying observed bioeffects is incomplete, (2) researchers do not as yet understand what physical aspects of exposure produce biological responses, and (3) health consequences resulting from ELF exposure are unknown. Although no animal studies clearly demonstrate deleterious effects of ELF fields, several are suggestive of potential health impacts. From the perspective of laboratory animal studies, this paper will discuss biological responses to ELF magnetic and/or electric field exposures.

  13. Scaling investigation for the dynamics of charged particles in an electric field accelerator

    NASA Astrophysics Data System (ADS)

    Gouvêa Ladeira, Denis; Leonel, Edson D.

    2012-12-01

    Some dynamical properties of an ensemble of trajectories of individual (non-interacting) classical particles of mass m and charge q interacting with a time-dependent electric field and suffering the action of a constant magnetic field are studied. Depending on both the amplitude of oscillation of the electric field and the intensity of the magnetic field, the phase space of the model can either exhibit: (i) regular behavior or (ii) a mixed structure, with periodic islands of regular motion, chaotic seas characterized by positive Lyapunov exponents, and invariant Kolmogorov-Arnold-Moser curves preventing the particle to reach unbounded energy. We define an escape window in the chaotic sea and study the transport properties for chaotic orbits along the phase space by the use of scaling formalism. Our results show that the escape distribution and the survival probability obey homogeneous functions characterized by critical exponents and present universal behavior under appropriate scaling transformations. We show the survival probability decays exponentially for small iterations changing to a slower power law decay for large time, therefore, characterizing clearly the effects of stickiness of the islands and invariant tori. For the range of parameters used, our results show that the crossover from fast to slow decay obeys a power law and the behavior of survival orbits is scaling invariant.

  14. Numerical Investigation of Two-Phase Flows With Charged Droplets in Electrostatic Field

    NASA Technical Reports Server (NTRS)

    Kim, Sang-Wook

    1996-01-01

    A numerical method to solve two-phase turbulent flows with charged droplets in an electrostatic field is presented. The ensemble-averaged Navier-Stokes equations and the electrostatic potential equation are solved using a finite volume method. The transitional turbulence field is described using multiple-time-scale turbulence equations. The equations of motion of droplets are solved using a Lagrangian particle tracking scheme, and the inter-phase momentum exchange is described by the Particle-In-Cell scheme. The electrostatic force caused by an applied electrical potential is calculated using the electrostatic field obtained by solving a Laplacian equation and the force exerted by charged droplets is calculated using the Coulombic force equation. The method is applied to solve electro-hydrodynamic sprays. The calculated droplet velocity distributions for droplet dispersions occurring in a stagnant surrounding are in good agreement with the measured data. For droplet dispersions occurring in a two-phase flow, the droplet trajectories are influenced by aerodynamic forces, the Coulombic force, and the applied electrostatic potential field.

  15. Laboratory and field investigations of particulate and carbon monoxide emissions from traditional and improved cookstoves

    NASA Astrophysics Data System (ADS)

    Roden, Christoph A.; Bond, Tami C.; Conway, Stuart; Osorto Pinel, Anibal Benjamin; MacCarty, Nordica; Still, Dean

    We implemented a program in which emission characterization is enabled through collaborations between academic, US and international non-governmental entities that focus on evaluation, dissemination, and in-use testing, of improved cookstoves. This effort resulted in a study of field and laboratory emissions from traditional and improved biofuel cookstoves. We found that field measured particulate emissions of actual cooking average three times those measured during simulated cooking in the laboratory. Emission factors are highly dependent on the care and skill of the operator and the resulting combustion; these do not appear to be accurately reproduced in laboratory settings. The single scattering albedo (SSA) of the emissions was very low in both lab and field measurements, averaging about 0.3 for lab tests and around 0.5 for field tests, indicating that the primary particles are climate warming. Over the course of three summers in Honduras, we measured field emissions from traditional cookstoves, relatively new improved cookstoves, and "broken-in" improved cookstoves. We found that well-designed improved cookstoves can significantly reduce PM and CO emission factors below traditional cookstoves. For improved stoves, the presence of a chimney generally resulted in lower emission factors but left the SSA unaffected. Traditional cookstoves had an average PM emission factor of 8.2 g kg -1 - significantly larger than previous studies. Particulate emission factors for improved cookstoves without and with chimneys averaged about 6.6 g kg -1 and 4.5 g kg -1, respectively. The elemental carbon (EC) fraction of PM varied significantly between individual tests, but averaged about 25% for each of the categories.

  16. Investigation of superparamagnetic (Fe3O4) nanoparticles and magnetic field exposures on CHO-K1 cell line

    NASA Astrophysics Data System (ADS)

    Coker, Zachary; Estlack, Larry; Hussain, Saber; Choi, Tae-Youl; Ibey, Bennett L.

    2016-03-01

    Rapid development in nanomaterial synthesis and functionalization has led to advanced studies in actuation and manipulation of cellular functions for biomedical applications. Often these actuation techniques employ externally applied magnetic fields to manipulate magnetic nanomaterials inside cell bodies in order to drive or trigger desired effects. While cellular interactions with low-frequency magnetic fields and nanoparticles have been extensively studied, the fundamental mechanisms behind these interactions remain poorly understood. Additionally, modern investigations on these concurrent exposure conditions have been limited in scope, and difficult to reproduce. This study presents an easily reproducible method of investigating the biological impact of concurrent magnetic field and nanoparticle exposure conditions using an in-vitro CHO-K1 cell line model, with the purpose of establishing grounds for in-depth fundamental studies of the mechanisms driving cellular-level interactions. Cells were cultured under various nanoparticle and magnetic field exposure conditions from 0 to 500 μg/ml nanoparticle concentrations, and DC, 50 Hz, or 100 Hz magnetic fields with 2.0 mT flux density. Cells were then observed by confocal fluorescence microscopy, and subject to biological assays to determine the effects of concurrent extreme-low frequency magnetic field and nanoparticle exposures on cellnanoparticle interactions, such as particle uptake and cell viability by MTT assay. Current results indicate little to no variation in effect on cell cultures based on magnetic field parameters alone; however, it is clear that deleterious synergistic effects of concurrent exposure conditions exist based on a significant decrease in cell viability when exposed to high concentrations of nanoparticles and concurrent magnetic field.

  17. Investigation of the structure of the electromagnetic field and related phenomena, generated by the active satellite

    NASA Technical Reports Server (NTRS)

    Alpert, Yakov L.

    1992-01-01

    A short review is given for the general frequency and angle distribution of the electric field radiated by an electric dipole E = E(sub 0)cos(omega)t, in a magnetoplasma. Detailed results of numerical calculations of (E) were made in the Very Low Frequency (VLF) and the Low Frequency (LF) bands 0.02f(sub b) is less than or equal to F is less than or equal to 0.5f(sub b) (F is approximately (4-500) kHz) in the ionosphere and magnetosphere in the altitude region Z = (800-6000) km; f(sub b) is the electron gyro-frequency of the plasmas in the discussed region f(sub b) is approximately equal to (1.1 to 0.2) MHz. The amplitudes of the electric field have large maxima in four regions: close to the direction of the Earth's magnetic field line (B(sub 0)), it is the so called Axis field (E(sub 0)) and in the Storey (E(sub St)), Reversed Storey (E(sub RevSt)), and Resonance (E(sub Res)) Cones. The maximal values of E(sub 0), E(sub Res), and E(sub RevSt) are very pronounced close to the low hybrid frequency, F approximately F(sub L). The flux of the electric field is concentrated in very narrow regions, the apex angles of the cones delta(beta) is approximately equal to (0.1 - 1) degree. The enhancement and focusing of the electric field is growing up, especially quickly at Z greater than 800 km. At Z is greater than 1000 up to 6000 km, the relative value of (E), in comparison with its value at Z = 800 km is about (10(exp 2) to 10(exp 4)) times larger. Thus, the flux of VLF and LF electromagnetic waves in the Earth magnetoplasma produces and is guided by very narrow pencil beams, similar, let us say, to laser beams.

  18. Field investigation into the diffusion of semi-volatile organic compounds into fresh and aged snow

    NASA Astrophysics Data System (ADS)

    Herbert, B. M. J.; Halsall, C. J.; Jones, K. C.; Kallenborn, R.

    Empirically derived field diffusivities were determined over a 24 h period for a selection of anthropogenic chlorinated chemicals in both fresh and aged snow at Tromsø, Norway. Diffusivities in fresh snow were 4.91×10 -2, 4.79×10 -1, 4.75×10 -2 and 4.75×10 -2 cm 2 s -1 for PCB-6, HCB and α-/ γ-HCH, respectively. These field diffusivities were compared to theoretical diffusivities (assuming no interaction between the chemical vapour and ice surfaces) and effective diffusivities (assuming sorption of the chemical vapour to the ice surface). Theoretical diffusivities were the highest values and were in good agreement with the empirical diffusivities derived from the field data. This suggests that the test chemicals used in this study have a low affinity for the snow/ice surfaces during diffusion into the snow. Differences in calculated diffusivities between these compounds can be largely accounted for by their physical-chemical properties, notably their snow interfacial-air partition coefficients ( Kia snow). However, using calculated values of Kia snow to describe sorption to the snow surfaces greatly reduced the effective diffusivities of the chemicals relative to the empirical field diffusivities, and calls into question the accuracy of Kia snow and/or its suitability for describing snow/air interactions at the relatively mild temperatures encountered in this study. Comparison of diffusivities between fresh and aged snow revealed similar values (within the same order of magnitude) and may be due to similar porosities between the snow types, although this parameter was not measured. Mass transfer coefficients were determined using the empirical field diffusivities and depth of the snow-layer, allowing chemical fluxes from snow to air to be calculated through use of the Whitman two-film resistance model. Using derived fluxes the chemical half-lives ( t1/2) in fresh snow were calculated assuming that snow metamorphosis did not occur. The half-lives were in good

  19. ENVIRONMENTAL CARCINOGENESIS IN THE MUMMICHOG, FUNDULUS HETEROCLITUS: FIELD AND LABORATORY INVESTIGATIONS

    EPA Science Inventory

    The mummichog, Fundulus heteroclitus, is a small estuarine teleost inhabiting coastal embayments along much of the eastern seaboard of the US. We have been investigating an association between chemical contaminant exposure and adverse health impacts in this small cyprinodontid fi...

  20. Investigation of the Sterol Composition and Azole Resistance in Field Isolates of Septoria tritici

    PubMed Central

    Joseph-Horne, T.; Hollomon, D.; Manning, N.; Kelly, S. L.

    1996-01-01

    We report here a biochemical study of resistance to azole antifungal agents in a field isolate (S-27) of a fungal phytopathogen. Isolates of Septoria tritici were compared in vitro, and their responses reflected that observed in the field, with S-27 exhibiting resistance relative to RL2. In untreated cultures, both RL2 and S-27 contained isomers of ergosterol and ergosta-5,7-dienol, although in differing concentrations. Under azole treatment, this phytopathogen exhibited a response similar to that of other pathogenic fungi, with a reduction in desmethyl sterols and an accumulation of 14(alpha)-methyl sterols, indicative of inhibition of the P450-mediating sterol 14(alpha)-demethylase. Growth arrest was attributed to the reduction of ergosterol combined with an accumulation of nonutilizable sterols. Strain S-27 exhibited an azole-resistant phenotype which was correlated with decreased cellular content of azole. PMID:16535210

  1. Numerical investigation and optimization on mixing enhancement factors in supersonic jet-to-crossflow flow fields

    NASA Astrophysics Data System (ADS)

    Yan, Li; Huang, Wei; Li, Hao; Zhang, Tian-tian

    2016-10-01

    Sufficient mixing between the supersonic airstream and the injectant is critical for the design of scramjet engines. The information in the two-dimensional supersonic jet-to-crossflow flow field has been explored numerically and theoretically, and the numerical approach has been validated against the available experimental data in the open literature. The obtained results show that the extreme difference analysis approach can obtain deeper information than the variance analysis method, and the optimal strategy can be generated by the extreme difference analysis approach. The jet-to-crossflow pressure ratio is the most important influencing factor for the supersonic jet-to-crossflow flow field, following is the injection angle, and all the design variables have no remarkable impact on the separation length and the height of Mach disk in the range considered in the current study.

  2. Investigation on Transient Oscillation of Droplet Deformation before Conical Breakup under Alternating Current Electric Field.

    PubMed

    Yan, Haipeng; He, Limin; Luo, Xiaoming; Wang, Jing; Huang, Xin; Lü, Yuling; Yang, Donghai

    2015-08-04

    In this paper, the conical breakup of a water droplet suspended in oil under the alternating current (ac) electric field was experimentally studied with the help of a high-speed video camera. We observed three stages of transient oscillation of deformation characterized by deformation degree l* before the conical breakup that were described in detail. Then a theoretical model was developed to find out the dynamic mechanisms of that behavior. Despite a very small discrepancy, good agreement between model predictions and experimental observations of the evolution of the droplet deformation was observed, and the possible reasons for the discrepancy were discussed as well. Finally, the stresses on the interface were calculated with the theoretical model and their influence on the dynamic behavior before the breakup was obtained. The differences between the droplet breakup mode of ac and direct current electric field are also discussed in our paper.

  3. The erosion of carbonate stone by acid rain: Laboratory and field investigations

    USGS Publications Warehouse

    Baedecker, P.A.; Reddy, M.M.

    1993-01-01

    One of the goals of research on the effects of acidic deposition on carbonate stone surfaces is to define the incremental impact of acidic deposition relative to natural weathering processes on the rate of carbonate stone erosion. If rain that impacts carbonate stone surfaces is resident on the surface long enough to approach chemical equilibrium, the incremental effect of hydrogen ion is expected to be small (i.e., 6% for a rain of pH 4.0). Under nonequilibrium (i.e., high flow rate) conditions, kinetic considerations suggest that the incremental effect of hydrogen ion deposition could be quite significant. Field run-off experiments involving the chemical analysis of rain collected from inclined stone slabs have been used to evaluate stone dissolution processes under ambient conditions of wet and dry deposition of acidic species. The stoichiometry of the reaction of stone with hydrogen ion is difficult to define from the field data due to scatter in the data attributed to hydrodynamic effects. Laboratory run-off experiments show that the stoichiometry is best defined by a reaction with H+ in which CO2 is released from the system. The baseline effect caused by water in equilibrium with atmospheric CO2 is identical in the field and in laboratory simulation. The experiments show that the solutions are close enough to equilibrium for the incremental effect of hydrogen ion to be minor (i.e., 24% for marble for a rain of pH 4.0) relative to dissolution due to water and carbonic acid reactions. Stone erosion rates based on physical measurement are approximately double the recession rates that are due to dissolution (estimated from the observed calcium content of the run-off solutions). The difference may reflect the loss of granular material not included in recession estimates based on the run-off data. Neither the field nor the laboratory run-off experiments indicate a pH dependence for the grain-removal process.

  4. Investigations of Magnetic Field Disturbances at Little Rock Air Force Base Compass Calibration Hardstand

    DTIC Science & Technology

    1990-09-01

    magnetic field disturbance. Examination of a piece of the hardstand concrete reveals that the aggregate is igneous (nepheline syenite )-with magnetite as an...nepheline syenite ) with magnetite as an accessory mineral. The permanent magnetization of the aggregate is sufficient to visibly deflect the needle...aggregate is a dark, igneous material (Figure 10). The aggregate is from a well known local quarry, and is identified as nepheline syenite , which has

  5. MFE/Magnolia - A joint CNES/NASA mission for the earth magnetic field investigation

    NASA Technical Reports Server (NTRS)

    Runavot, Josette; Ousley, Gilbert W.

    1988-01-01

    The joint phase B study in the CNES/NASA MFE/Magnolia mission to study the earth's magnetic field are reported. The scientific objectives are summarized and the respective responsibilities of NASA and CNES are outlined. The MFE/Magnolia structure and power systems, mass and power budgets, attitude control system, instrument platform and boom, tape recorders, rf system, propellant system, and scientific instruments are described.

  6. Motor Testing at 1 Year Improves the Prediction of Motor and Mental Outcome at 2 Years after Perinatal Hypoxic-Ischaemic Encephalopathy

    ERIC Educational Resources Information Center

    van Schie, Petra Em; Becher, Jules G.; Dallmeijer, Annet J.; Barkhof, Frederik; van Weissenbruch, Mirjam M.; Vermeulen, R. Jeroen

    2010-01-01

    Aim: To investigate the predictive value of motor testing at 1 year for motor and mental outcome at 2 years after perinatal hypoxic-ischaemic encephalopathy (HIE) in term neonates. Method: Motor and mental outcome at 2 years was assessed with the Bayley Scales of Infant Development, 2nd edition (BSID-II) in 32 surviving children (20 males, 12…

  7. Food production and nutrition for the crew during the first 2-year closure of Biosphere 2.

    PubMed

    Silverstone, S E

    1997-01-01

    Biosphere 2's finite natural resources: atmosphere, plants, water, and soil, and its unique increased rate of nutrient cycling, mandated a design for the agriculture that emphasized sustainability and high productivity. The results of the initial 2-year test of the agriculture system showed that it could provide a diet that was both nutritionally adequate and pleasing to the palate of the eight-member crew from September 1991 to September 1993. The agriculture design was developed from 1985 to 1991 at the Space Biospheres research greenhouses with consulting from the Institute of Ecotechnics (London) from its experiments in New Mexico, Australia, and France and the Environmental Research Laboratory (University of Arizona). During the 2-year mission this research was continued with the close collaboration of outside scientific consultants, particularly in the area of soil management and integrated pest management. The 2000-m2 cropping area provided approximately 81% of the overall nutritional needs of the crew. Initial results showed light to be the main limiting factor and the additional electric light was added after the first 2-year mission to increase the productivity for future experiments. The diet was primarily vegetarian supplemented with daily amounts of milk, and weekly meals of meat and eggs from the system's domestic goats, pigs, and chickens. Nontoxic methods of pest and disease control were used. The main pest problems were broad mite and root knot nematode. Inedible plant material, domestic animal wastes, and human waste water were successfully processed for nutrient return to the soil. Eighty-six varieties of crops were grown in Biosphere 2. Major staple crops included rice, sweet potato, beets, banana, and papaya. The African pygmy goats were the most productive of the domestic animals producing on average 1.14 kg of milk per day. The diet averaged 2200 calories, 73 g of protein, and 32 g of fat per person per day over the 2 years. The crew had a 10

  8. Investigation of the interfacial tension of complex coacervates using field-theoretic simulations

    SciTech Connect

    Kumar, Rajeev

    2012-01-01

    Complex coacervation, a liquid-liquid phase separation that occurs when two oppositely charged polyelectrolytes are mixed in a solution, has the potential to be exploited for many emerging applications including wet adhesives and drug delivery vehicles. The ultra-low interfacial tension of coacervate systems against water is critical for such applications, and it would be advantageous if molecular models could be used to characterize how various system properties (e.g., salt concentration) affect the interfacial tension. In this article we use field-theoretic simulations to characterize the interfacial tension between a complex coacervate and its supernatant. After demonstrating that our model is free of ultraviolet divergences (calculated properties converge as the collocation grid is refined), we develop two methods for calculating the interfacial tension from field-theoretic simulations. One method relies on the mechanical interpretation of the interfacial tension as the interfacial pressure, and the second method estimates the change in free energy as the area between the two phases is changed. These are the first calculations of the interfacial tension from full field theoretic simulation of which we are aware, and both the magnitude and scaling behaviors of our calculated interfacial tension agree with recent experiments.

  9. Investigation of Coastal Wind Fields over the Black Sea Using Envisat

    NASA Astrophysics Data System (ADS)

    Alpers, Werner; Ivanov, Andrei Yu.; Dagestad, Knut-Frode

    2010-12-01

    The sea area off the east coast of the Black Sea is an area where often pronounced local winds are encountered. The most prominent one is the Novorossiyskaya bora, which is a strong wind blowing from the coastal mountains onto the Black Sea, which can attain speeds of up to 40 ms-1. But also katabatic winds and foehn winds are often encountered in this area. We have analyzed seven coastal wind events by using synthetic aperture radar (SAR) images acquired by the Advanced Synthetic Aperture Radar (ASAR) onboard the European Envisat satellite. The winds modify the sea surface roughness and thus they become visible on SAR images. Information on the spatial extent and the fine-scale structure of the coastal wind fields can be obtained from these images. In particular, SAR images can be used to study 1) wind jets, wakes, and atmospheric eddies generated by the interaction of winds with coastal topography, 2) boundaries between the local and ambient wind fields, and 3) atmospheric gravity waves (AGWs). Quantitative information on the near-surface wind field is derived from the SAR images by using the CMOD4 wind scatterometer model for converting radar backscatter values into wind speeds. It is argued that the east coast of the Black Sea is an ideal test area for validating meso-scale atmospheric models.

  10. Experimental Investigation of Electron Cloud Containment in a Nonuniform Magnetic Field

    NASA Technical Reports Server (NTRS)

    Eninger, J. E.

    1974-01-01

    Dense clouds of electrons were generated and studied in an axisymmetric, nonuniform magnetic field created by a short solenoid. The operation of the experiment was similar to that of a low-pressure (approximately 0.000001 Torr) magnetron discharge. Discharge current characteristics are presented as a function of pressure, magnetic field strength, voltage, and cathode end-plate location. The rotation of the electron cloud is determined from the frequency of diocotron waves. In the space charge saturated regime of operation, the cloud is found to rotate as a solid body with frequency close to V sub a/phi sub a where V sub a is the anode voltage and phi suba is the total magnetic flux. This result indicates that, in regions where electrons are present, the magnetic field lines are electrostatic equipotentials (E bar, B bar = 0). Equilibrium electron density distributions suggested by this conditions are integrated with respect to total ionizing power and are found consistent with measured discharge currents.

  11. Theoretical investigation of single dopant in core/shell nanocrystal in magnetic field

    NASA Astrophysics Data System (ADS)

    Talbi, A.; Feddi, E.; Oukerroum, A.; Assaid, E.; Dujardin, F.; Addou, M.

    2015-09-01

    The control of single dopant or "solitary dopant" in semiconductors constitute a challenge to achieve new range of tunable optoelectronic devices. Knowing that the properties of doped monocrystals are very sensitive to different external perturbations, the aim of this study is to understand the effect of a magnetic field on the ground state energy of an off-center ionized donor in a core/shell quantum dot (CSQD). The binding energies with and without an applied magnetic field are determined by the Ritz variational method taking into account the electron-impurity correlation in the trial wave function deduced from the second-order perturbation. It has been found that the external magnetic field affects strongly the binding energy, and its effect varies as a function of the core radius and the shell thickness. We have shown the existence of a threshold ratio (a / b) crit which represents the limit between the tridimensional and the spherical surface confinement. In addition our analysis demonstrates the important influence of the position of ionized donor in the shell material.

  12. Numerical and experimental investigation of a beveled trailing-edge flow field and noise emission

    NASA Astrophysics Data System (ADS)

    van der Velden, W. C. P.; Pröbsting, S.; van Zuijlen, A. H.; de Jong, A. T.; Guan, Y.; Morris, S. C.

    2016-12-01

    Efficient tools and methodology for the prediction of trailing-edge noise experience substantial interest within the wind turbine industry. In recent years, the Lattice Boltzmann Method has received increased attention for providing such an efficient alternative for the numerical solution of complex flow problems. Based on the fully explicit, transient, compressible solution of the Lattice Boltzmann Equation in combination with a Ffowcs-Williams and Hawking aeroacoustic analogy, an estimation of the acoustic radiation in the far field is obtained. To validate this methodology for the prediction of trailing-edge noise, the flow around a flat plate with an asymmetric 25° beveled trailing edge and obtuse corner in a low Mach number flow is analyzed. Flow field dynamics are compared to data obtained experimentally from Particle Image Velocimetry and Hot Wire Anemometry, and compare favorably in terms of mean velocity field and turbulent fluctuations. Moreover, the characteristics of the unsteady surface pressure, which are closely related to the acoustic emission, show good agreement between simulation and experiment. Finally, the prediction of the radiated sound is compared to the results obtained from acoustic phased array measurements in combination with a beamforming methodology. Vortex shedding results in a strong narrowband component centered at a constant Strouhal number in the acoustic spectrum. At higher frequency, a good agreement between simulation and experiment for the broadband noise component is obtained and a typical cardioid-like directivity is recovered.

  13. Rover-Based Instrumentation and Scientific Investigations During the 2012 Analog Field Test on Mauna Kea Volcano, Hawaii

    NASA Technical Reports Server (NTRS)

    Graham, L. D.; Graff, T. G.

    2013-01-01

    Rover-based 2012 Moon and Mars Analog Mission Activities (MMAMA) were recently completed on Mauna Kea Volcano, Hawaii. Scientific investigations, scientific input, and operational constraints were tested in the context of existing project and protocols for the field activities designed to help NASA achieve the Vision for Space Exploration [1]. Several investigations were conducted by the rover mounted instruments to determine key geophysical and geochemical properties of the site, as well as capture the geological context of the area and the samples investigated. The rover traverse and associated science investigations were conducted over a three day period on the southeast flank of the Mauna Kea Volcano, Hawaii. The test area was at an elevation of 11,500 feet and is known as "Apollo Valley" (Fig. 1). Here we report the integration and operation of the rover-mounted instruments, as well as the scientific investigations that were conducted.

  14. The investigation of active Martian dune fields using very high resolution photogrammetric measurements

    NASA Astrophysics Data System (ADS)

    Kim, Jungrack; Kim, Younghwi; Park, Minseong

    2016-10-01

    At the present time, arguments continue regarding the migration speeds of Martian dune fields and their correlation with atmospheric circulation. However, precisely measuring the spatial translation of Martian dunes has succeeded only a very few times—for example, in the Nili Patera study (Bridges et al. 2012) using change-detection algorithms and orbital imagery. Therefore, in this study, we developed a generic procedure to precisely measure the migration of dune fields with recently introduced 25-cm resolution orbital imagery specifically using a high-accuracy photogrammetric processor. The processor was designed to trace estimated dune migration, albeit slight, over the Martian surface by 1) the introduction of very high resolution ortho images and stereo analysis based on hierarchical geodetic control for better initial point settings; 2) positioning error removal throughout the sensor model refinement with a non-rigorous bundle block adjustment, which makes possible the co-alignment of all images in a time series; and 3) improved sub-pixel co-registration algorithms using optical flow with a refinement stage conducted on a pyramidal grid processor and a blunder classifier. Moreover, volumetric changes of Martian dunes were additionally traced by means of stereo analysis and photoclinometry. The established algorithms have been tested using high-resolution HIRISE time-series images over several Martian dune fields. Dune migrations were iteratively processed both spatially and volumetrically, and the results were integrated to be compared to the Martian climate model. Migrations over well-known crater dune fields appeared to be almost static for the considerable temporal periods and were weakly correlated with wind directions estimated by the Mars Climate Database (Millour et al. 2015). As a result, a number of measurements over dune fields in the Mars Global Dune Database (Hayward et al. 2014) covering polar areas and mid-latitude will be demonstrated

  15. Restricted Consonant Inventories of 2-Year-Old Finnish Children with a History of Recurrent Acute Otitis Media

    ERIC Educational Resources Information Center

    Haapala, Sini; Niemitalo-Haapola, Elina; Raappana, Antti; Kujala, Tiia; Kujala, Teija; Jansson-Verkasalo, Eira

    2015-01-01

    Many children experience recurrent acute otitis media (RAOM) in early childhood. In a previous study, 2-year-old children with RAOM were shown to have immature neural patterns for speech sound discrimination. The present study further investigated the consonant inventories of these same children using natural speech samples. The results showed…

  16. Overview of NASA Finesse (Field Investigations to Enable Solar System Science and Exploration) Science and Exploration Project

    NASA Technical Reports Server (NTRS)

    Heldmann, J. L.; Lim, D.S.S.; Hughes, S.; Nawotniak, S. Kobs; Garry, B.; Sears, D.; Neish, C.; Osinski, G. R.; Hodges, K.; Downs, M.; Busto, J.; Cohen, B.; Caldwell, B.; Jones, A. J. P.; Johnson, S.; Kobayashi, L.; Colaprete, A.

    2016-01-01

    NASA's FINESSE (Field Investigations to Enable Solar System Science and Exploration) project was selected as a research team by NASA's Solar System Exploration Research Virtual Institute (SSERVI). SSERVI is a joint Institute supported by NASA's Science Mission Directorate (SMD) and Human Exploration and Operations Mission Directorate (HEOMD). As such, FINESSE is focused on a science and exploration field-based research program to generate strategic knowledge in preparation for human and robotic exploration of other planetary bodies including our Moon, Mars moons Phobos and Deimos, and near-Earth asteroids. FINESSE embodies the philosophy that "science enables exploration and exploration enables science".

  17. Investigation of MAGSAT and TRIAD magnetometer data to provide corrective information on high-latitude external fields

    NASA Technical Reports Server (NTRS)

    Potemra, T. A. (Principal Investigator)

    1981-01-01

    The compilation of a catalog of the MAGSAT-observed high altitude disturbances is discussed and an example of contents and format is given. The graphs allow the investigation of Birkeland current signatures which are superimposed upon the main geomagnetic field. An example of a display of the MAGSAT orbital tracks in a polar geomagnetic coordinate system with the locations, flow directions, and intensities of field aligned currents shown in color is also given. The display was generated using an interactive color graphics terminal.

  18. Field Investigations of Lactate-Stimulated Bioreduction of Cr(VI) to Cr(III) at Hanford 100H

    SciTech Connect

    T.C. Hazen; B. Faybishenko; J. Wan; T.Tokunaga; S. Hubbard; M. Conrad; S. Borglin; D. Joyner; S. Koenigsberg; A. Willet

    2004-03-17

    The objective of this report is to perform field investigations to assess the potential for immobilizing and detoxifying chromium contaminated soils and groundwater using bioremediation at Site 100H at Hanford. Specific goals are: (1) Designing a field test to measure the effect of lactate biostimulation on microbial community activity, redox gradients, transport limitations, and other reducing agents in comparison with our previous NABIR laboratory work. (2) Establishing the rates and conditions that may cause are oxidation of Cr(III) to Cr(VI) following biostimulation. (3) Providing design criteria for full-scale deployment on in situ Cr(VI) bioreduction via lactate stimulation for use at DOE sites.

  19. Management of hereditary gingival fibromatosis: A 2 years follow-up case report

    PubMed Central

    Tripathi, Amitandra Kumar; Dete, Gopal; Saimbi, Charanjeet Singh; Kumar, Vivek

    2015-01-01

    Hereditary gingival fibromatosis (HGF) is a rare hereditary condition characterized by slow, progressive, nonhemorrhagic, fibrous enlargement of gingiva due to increase in sub-mucosal connective tissue component. This paper presents a case report of an 18-year-old female suffering from HGF with positive family history. Her 42-year-old mother also have enlargement of the gums. After through clinical examination of both the patients, routine blood investigation was advised. All the investigations were within normal physiological limits of both the patients. Surgical excision of enlarged gingival tissue was planned after meticulous scaling and root planing. Patients were recalled 1 week after surgery. Postoperative healing were good and desired crown lengthening was achieved with significant improvement in speech and masticatory problems in both the patients. There was no recurrence of the disease even after 2 years follow-up. PMID:26229281

  20. Management of hereditary gingival fibromatosis: A 2 years follow-up case report.

    PubMed

    Tripathi, Amitandra Kumar; Dete, Gopal; Saimbi, Charanjeet Singh; Kumar, Vivek

    2015-01-01

    Hereditary gingival fibromatosis (HGF) is a rare hereditary condition characterized by slow, progressive, nonhemorrhagic, fibrous enlargement of gingiva due to increase in sub-mucosal connective tissue component. This paper presents a case report of an 18-year-old female suffering from HGF with positive family history. Her 42-year-old mother also have enlargement of the gums. After through clinical examination of both the patients, routine blood investigation was advised. All the investigations were within normal physiological limits of both the patients. Surgical excision of enlarged gingival tissue was planned after meticulous scaling and root planing. Patients were recalled 1 week after surgery. Postoperative healing were good and desired crown lengthening was achieved with significant improvement in speech and masticatory problems in both the patients. There was no recurrence of the disease even after 2 years follow-up.

  1. OTC Cough and Cold Products: Not for Infants and Children Under 2 Years of Age

    MedlinePlus

    ... Cold Products: Not For Infants and Children Under 2 Years of Age Share Tweet Linkedin Pin it ... and cold products for infants and children under 2 years of age? A. FDA strongly recommends that ...

  2. Investigation of Workplace-like Calibration Fields via a Deuterium-Tritium (D-T) Neutron Generator.

    PubMed

    Mozhayev, Andrey V; Piper, Roman K; Rathbone, Bruce A; McDonald, Joseph C

    2017-04-01

    Radiation survey meters and personal dosimeters are typically calibrated in reference neutron fields based on conventional radionuclide sources, such as americium-beryllium (Am-Be) or californium-252 (Cf), either unmodified or heavy-water moderated. However, these calibration neutron fields differ significantly from the workplace fields in which most of these survey meters and dosimeters are being used. Although some detectors are designed to yield an approximately dose-equivalent response over a particular neutron energy range, the response of other detectors is highly dependent upon neutron energy. This, in turn, can result in significant over- or underestimation of the intensity of neutron radiation and/or personal dose equivalent determined in the work environment. The use of simulated workplace neutron calibration fields that more closely match those present at the workplace could improve the accuracy of worker, and workplace, neutron dose assessment. This work provides an overview of the neutron fields found around nuclear power reactors and interim spent fuel storage installations based on available data. The feasibility of producing workplace-like calibration fields in an existing calibration facility has been investigated via Monte Carlo simulations. Several moderating assembly configurations, paired with a neutron generator using the deuterium tritium (D-T) fusion reaction, were explored.

  3. Flow-Field Investigation of Gear-Flap Interaction on a Gulfstream Aircraft Model

    NASA Technical Reports Server (NTRS)

    Yao, Chung-Sheng; Jenkins, Luther N.; Bartram, Scott M.; Harris, Jerome; Khorrami, Mehdi R.; Mace, W. Derry

    2014-01-01

    Off-surface flow measurements of a high-fidelity 18% scale Gulfstream aircraft model in landing configuration with the main landing gear deployed are presented. Particle Image Velocimetry (PIV) and Laser Velocimetry (LV) were used to measure instantaneous velocities in the immediate vicinity of the main landing gear and its wake and near the inboard tip of the flap. These measurements were made during the third entry of a series of tests conducted in the NASA Langley Research Center (LaRC) 14- by 22-Foot Subsonic Tunnel (14 x 22) to obtain a comprehensive set of aeroacoustic measurements consisting of both aerodynamic and acoustic data. The majority of the off-body measurements were obtained at a freestream Mach number of 0.2, angle of attack of 3 degrees, and flap deflection angle of 39 degrees with the landing gear on. A limited amount of data was acquired with the landing gear off. LV was used to measure the velocity field in two planes upstream of the landing gear and to measure two velocity profiles in the landing gear wake. Stereo and 2-D PIV were used to measure the velocity field over a region extending from upstream of the landing gear to downstream of the flap trailing edge. Using a special traverse system installed under the tunnel floor, the velocity field was measured at 92 locations to obtain a comprehensive picture of the pertinent flow features and characteristics. The results clearly show distinct structures in the wake that can be associated with specific components on the landing gear and give insight into how the wake is entrained by the vortex at the inboard tip of the flap.

  4. Investigation of the 3-D actinic flux field in mountainous terrain

    PubMed Central

    Wagner, J.E.; Angelini, F.; Blumthaler, M.; Fitzka, M.; Gobbi, G.P.; Kift, R.; Kreuter, A.; Rieder, H.E.; Simic, S.; Webb, A.; Weihs, P.

    2011-01-01

    During three field campaigns spectral actinic flux was measured from 290–500 nm under clear sky conditions in Alpine terrain and the associated O3- and NO2-photolysis frequencies were calculated and the measurement products were then compared with 1-D- and 3-D-model calculations. To do this 3-D-radiative transfer model was adapted for actinic flux calculations in mountainous terrain and the maps of the actinic flux field at the surface, calculated with the 3-D-radiative transfer model, are given. The differences between the 3-D- and 1-D-model results for selected days during the campaigns are shown, together with the ratios of the modeled actinic flux values to the measurements. In many cases the 1-D-model overestimates actinic flux by more than the measurement uncertainty of 10%. The results of using a 3-D-model generally show significantly lower values, and can underestimate the actinic flux by up to 30%. This case study attempts to quantify the impact of snow cover in combination with topography on spectral actinic flux. The impact of snow cover on the actinic flux was ~ 25% in narrow snow covered valleys, but for snow free areas there were no significant changes due snow cover in the surrounding area and it is found that the effect snow-cover at distances over 5 km from the point of interest was below 5%. Overall the 3-D-model can calculate actinic flux to the same accuracy as the 1-D-model for single points, but gives a much more realistic view of the surface actinic flux field in mountains as topography and obstruction of the horizon are taken into account. PMID:26412915

  5. Geologic and geophysical investigations of the Zuni-Bandera volcanic field, New Mexico

    SciTech Connect

    Ander, M.E.; Heiken, G.; Eichelberger, J.; Laughlin, A.W.; Huestis, S.

    1981-05-01

    A positive, northeast-trending gravity anomaly, 90 km long and 30 km wide, extends southwest from the Zuni uplift, New Mexico. The Zuni-Bandera volcanic field, an alignment of 74 basaltic vents, is parallel to the eastern edge of the anomaly. Lavas display a bimodal distribution of tholeiitic and alkalic compositions, and were erupted over a period from 4 Myr to present. A residual gravity profile taken perpendicular to the major axis of the anomaly was analyzed using linear programming and ideal body theory to obtain bounds on the density contrast, depth, and minimum thickness of the gravity body. Two-dimensionality was assumed. The limiting case where the anomalous body reaches the surface gives 0.1 g/cm/sup 3/ as the greatest lower bound on the maximum density contrast. If 0.4 g/cm/sup 3/ is taken as the geologically reasonable upper limit on the maximum density contrast, the least upper bound on the depth of burial is 3.5 km and minimum thickness is 2 km. A shallow mafic intrusion, emplaced sometime before Laramide deformation, is proposed to account for the positive gravity anomaly. Analysis of a magnetotelluric survey suggests that the intrusion is not due to recent basaltic magma associated with the Zuni-Bandera volcanic field. This large basement structure has controlled the development of the volcanic field; vent orientations have changed somewhat through time, but the trend of the volcanic chain followed the edge of the basement structure. It has also exhibited some control on deformation of the sedimentary section.

  6. Semantic field in aphasia: an experimental investigation on comprehension of the relations of class and property.

    PubMed

    Bisiacchi, P; Denes, G; Semenza, C

    1976-01-01

    A multiple choice test was devised in order to assess some aspects of the aphasic's semantic field; patient's task was to match a given picture with one out of three alternatives: one of them was linked by a class relationship, one was linked by a property relationship and the last was an unrelated item. Results clearly show that Broca's aphasics make their choice according to class criteria whereas Wernicke's and controls make their choice according to property criteria. Results are discussed in the light of Jakobson linguistic hypothesis which postulates that Broca's and Wernicke's aphasia are subdued by a contiguity and similarity disorder.

  7. Experimental investigations of the role of laser field fluctuations in non-linear optical absorption processes

    SciTech Connect

    Smith, S.J.

    1985-01-01

    In the experimental program described, we deliberately broaden a well-stabilized single mode laser beam by introducing fluctuations to the laser frequency, in order to synthesize laser power spectra for which the fluctuations are well-characterized to all orders in a statistical sense. With this technique we are able to produce single mode laser fields which have nearly Lorentzian power spectra at one limit, essentially Gaussian power spectra at the other limit, and which may be varied continuously between these two limits. 16 refs., 6 figs.

  8. Comparative investigation of ELM control based on toroidal modelling of plasma response to RMP fields

    NASA Astrophysics Data System (ADS)

    Liu, Yueqiang

    2016-10-01

    The type-I edge localized mode (ELM), bursting at low frequency and with large amplitude, can channel a substantial amount of the plasma thermal energy into the surrounding plasma-facing components in tokamak devices operating at the high-confinement mode, potentially causing severe material damages. Learning effective ways of controlling this instability is thus an urgent issue in fusion research, in particular in view of the next generation large devices such as ITER and DEMO. Among other means, externally applied, three-dimensional resonant magnetic perturbation (RMP) fields have been experimentally demonstrated to be successful in mitigating or suppressing the type-I ELM, in multiple existing devices. In this work, we shall report results of a comparative study of ELM control using RMPs. Comparison is made between the modelled plasma response to the 3D external fields and the observed change of the ELM behaviour on multiple devices, including MAST, ASDEX Upgrade, EAST, DIII-D, JET, and KSTAR. We show that toroidal modelling of the plasma response, based on linear and quasi-linear magnetohydrodynamic (MHD) models, provides essential insights that are useful in interpreting and guiding the ELM control experiments. In particular, linear toroidal modelling results, using the MARS-F code, reveal the crucial role of the edge localized peeling-tearing mode response during ELM mitigation/suppression on all these devices. Such response often leads to strong peaking of the plasma surface displacement near the region of weak equilibrium poloidal field (e.g. the X-point), and this provides an alternative practical criterion for ELM control, as opposed to the vacuum field based Chirikov criteria. Quasi-linear modelling using MARS-Q provides quantitative interpretation of the side effects due to the ELM control coils, on the plasma toroidal momentum and particle confinements. The particular role of the momentum and particle fluxes, associated with the neoclassical toroidal

  9. Mechanical interaction among normal faults: A numerical field and seismological investigation

    NASA Astrophysics Data System (ADS)

    Crider, Juliet Gage

    1998-12-01

    The segmentation of normal faults influences both their structural development and seismogenic character. In this study, field and seismological observations of normal faults from southern Oregon are combined with three-dimensional numerical modeling to illuminate the effect of mechanical interaction among fault segments. Field observations of two overlapping normal faults and associated deformation document features common to many normal-fault relay zones. A boundary element method numerical model, using simple fault-plane geometries, material properties, and boundary conditions, reproduces the principal characteristics of the observed fault scarps. The model produces a region of high Coulomb shear stress in the relay zone. The results suggest that the mechanical interaction between segments of a normal-fault system promote the development of connected, zigzagging fault scarps. The interplay between tectonic tension and lithostatic compression should strongly influence the near-surface behavior of surface-breaking normal faults. Four simple boundary conditions are evaluated for application to modeling surface-breaking normal faults. Map patterns of normal fault linkages from Lake County, Oregon show a systematic relationship between echelon step-sense, oblique extension direction, and the position of linking faults. When the step sense is the same as the sense of oblique extension, the faults are linked in the lower part of their relay ramp. When the step-sense and extension-sense are opposite, the faults are linked in the upper part of the ramp. The calculated stress fields around echelon normal faults reveal a relationship similar to the field observations. Thus, oblique slip alters the mechanical interaction among segments and influences the geometry of fault linkage. The 1993 Klamath Falls, Oregon earthquake sequence shows evidence for fault segmentation in the occurrence of two main shocks and in the spatial distribution of aftershocks. Late stage, off fault

  10. Laboratory and field investigations of wave attenuation by live marsh vegetation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wave attenuation by live marsh vegetation was investigated experimentally in this study. Laboratory experiments were conducted in a 20.6 m long, 0.69 m wide and 1.22 m deep wave flume under regular and random waves. The vegetation species used are Spartina alterniflora and Juncus roemerianus, which ...

  11. Drifting Continents and Magnetic Fields. Crustal Evolution Education Project. Teacher's Guide [and] Student Investigation.

    ERIC Educational Resources Information Center

    Stoever, Edward C., Jr.

    Crustal Evolution Education Project (CEEP) modules were designed to: (1) provide students with the methods and results of continuing investigations into the composition, history, and processes of the earth's crust and the application of this knowledge to man's activities and (2) to be used by teachers with little or no previous background in the…

  12. Going Underground: A Field Investigation and Lab Activity on Karst Topography and Water Systems

    ERIC Educational Resources Information Center

    O'Dell, Gary; Gonzalez-Espada, Wilson

    2011-01-01

    Students learn science best with activities that mirror the way scientists work. This article describes how geologists investigate groundwater flow systems in areas of karst topography--geologic formations shaped by dissolving bedrock--and provides a way for students to replicate this research. Students also use electric current to model water…

  13. Development of KSC program for investigating and generating field failure rates. Volume 1: Summary and overview

    NASA Technical Reports Server (NTRS)

    Bean, E. E.; Bloomquist, C. E.

    1972-01-01

    A summary of the KSC program for investigating the reliability aspects of the ground support activities is presented. An analysis of unsatisfactory condition reports (RC), and the generation of reliability assessment of components based on the URC are discussed along with the design considerations for attaining reliable real time hardware/software configurations.

  14. Studies of dynamo field structure and related effects: DE satellite project guest investigator program

    NASA Technical Reports Server (NTRS)

    Coley, W. R.

    1986-01-01

    The establishment of the latitudinal and longitudinal structure of the low latitude dynamo electric (DE) field was initiated using data primarily from the Unified Abstract (UA) files of the Atmosphere Explorer E (AE-E) satellite. Mass plots of the vertical ion drift values were made for 1977, 1978, and 1979. The average diurnal variation of V sub v within 20 degrees of the dip equator is remarkably similar to that obtained at Jicamarca in the same years. The average meridional ion drift velocity vectors, obtained as a function of latitude by combining the average vertical and horizontal (nearly north-south) ion drift values from the AE-E, showed the expected variations with local time and season based on the well known equatorial fountain effect theory. The average diurnal variation of the vertical drift was found for four different ranges of dip latitude for a northern solstice season. The effect of the transequatorial neutral winds was as evident in this plotting format as in the meridional or fountain effect format. Finally, the average vertical drift velocity V sub v, not the east-west electric field E sub ew, was found to be approximately independent of longitude, as expected from the dynamo theory.

  15. Investigating the fluid dynamics of rapid processes within microfluidic devices using bright-field microscopy.

    PubMed

    Pirbodaghi, Tohid; Vigolo, Daniele; Akbari, Samin; deMello, Andrew

    2015-05-07

    The widespread application of microfluidic devices in the biological and chemical sciences requires the implementation of complex designs and geometries, which in turn leads to atypical fluid dynamic phenomena. Accordingly, a complete understanding of fluid dynamics in such systems is key in the facile engineering of novel and efficient analytical tools. Herein, we present an accurate approach for studying the fluid dynamics of rapid processes within microfluidic devices using bright-field microscopy with white light illumination and a standard high-speed camera. Specifically, we combine Ghost Particle Velocimetry and the detection of moving objects in automated video surveillance to track submicron size tracing particles via cross correlation between the speckle patterns of successive images. The efficacy of the presented technique is demonstrated by measuring the flow field over a square pillar (80 μm × 80 μm) in a 200 μm wide microchannel at high volumetric flow rates. Experimental results are in excellent agreement with those obtained via computational fluid dynamics simulations. The method is subsequently used to study the dynamics of droplet generation at a flow focusing microfluidic geometry. A unique feature of the presented technique is the ability to perform velocimetry analysis of high-speed phenomena, which is not possible using micron-resolution particle image velocimetry (μPIV) approaches based on confocal or fluorescence microscopy.

  16. Investigating yellow dung fly body size evolution in the field: Response to climate change?

    PubMed

    Blanckenhorn, Wolf U

    2015-08-01

    Uncovering genetic responses to selection in wild populations typically requires tracking individuals over generations and use of animal models. Our group monitored the body size of one Swiss Yellow Dung Fly (Scathophaga stercoraria; Diptera: Scathophagidae) field population over 15 years, including intermittent common-garden rearing in the laboratory to assess body size with minimized environmental and maximized genetic variation. Contrary to expectations based on repeated heritability and phenotypic selection assessments over the years (reported elsewhere), field body sizes declined by >10% and common-garden laboratory sizes by >5% from 1993 to 2009. Our results confirm the temperature-size rule (smaller when warmer) and, albeit entirely correlational, could be mediated by climate change, as over this period mean temperature at the site increased by 0.5°C, although alternative systematic environmental changes cannot be entirely excluded. Monitoring genetic responses to selection in wild invertebrate populations is thus possible, though indirect, and wild populations may evolve in directions not consistent with strongly positive directional selection favoring large body size.

  17. Biosensing with microbial fuel cells and artificial neural networks: laboratory and field investigations.

    PubMed

    Feng, Yinghua; Harper, Willie F

    2013-11-30

    In this study microbial fuel cell-based biosensing was integrated with artificial neural networks (ANNs) in laboratory and field testing of water samples. Inoculation revealed two types of anode-respiring bacteria (ARB) induction profiles, a relatively slow gradual profile and a faster profile that was preceded by a significant lag time. During laboratory testing, the MFCs generated well-organized normally distributed profiles but during field experiments the peaks had irregular shapes and were smaller in magnitude. Generally, the COD concentration correlated better with peak area than with peak height. The ANN predicted the COD concentration (R(2) = 0.99) with one layer of hidden neurons and for concentrations as low as 5 mg acetate-COD/L. Adding 50 mM of 2-bromoethanesulfonate amplified the electrical signals when glucose was the substrate. This report is the first to identify two types of ARB induction profiles and to demonstrate the power of ANNs for interpreting a wide variety of electrical response peaks.

  18. An investigation of in-flight near-field propeller noise generation and transmission

    NASA Astrophysics Data System (ADS)

    Bonneau, H.; Wilford, D. F.; Wood, L. K.

    1985-02-01

    In flight near field propeller noise measurements, made on a General Aviation turboprop aircraft, are reported for a range of propeller operating conditions, and are shown to be well defined and reproducible. Measurements have been made at 8 exterior microphones, 2 located on a wing mounted boom, and 6 embedded in, and flush with the aircraft fuselage. Interior noise levels are also presented. Measured propeller harmonic levels are compared to first principle calculations of near field noise, using a modified version of the Farassat computer program, in which the blade surface pressure is described using the known aerodynamic properties of the blade (NACA 16) airfoil sections. The first few; i.e., the dominant harmonic levels of propeller noise are shown to be well predicted, while higher harmonic levels are underpredicted. The transmission loss between exterior and interior noise levels is shown to be relatively constant for varying propeller operating conditions and at two different locations along the length of the fuselage. Interior noise levels are also shown for the aircraft in gliding flight at various forward velocities, with both engines at idle and propellers feathered. A method of interpolating these measurements is discussed, which allows the interior noise due only to the forward velocity of the aircraft, to be determined. The transmission loss for this component is also discussed. Finally, interior noise levels are presented for a series of ground static tests with engine mounts of various different stiffnessses.

  19. An Experimental Investigation of Steady and Unsteady Flow Field in an Axial Flow Turbine

    NASA Technical Reports Server (NTRS)

    Zaccaria, M.; Lakshminarayana, B.

    1997-01-01

    Measurements were made in a large scale single stage turbine facility. Within the nozzle passage measurements were made using a five hole probe, a two-component Laser Doppler Velocimeter (LDV), and a single sensor hot wire probe. These measurements showed weak secondary flows at midchord, and two secondary flow loss cores at the nozzle exit. The casing vortex loss core was the larger of the two. At the exit radial inward flow was found over the entire passage, and was more pronounced in the wake. Nozzle wake decay was found to be more rapid than for an isolated vane row due to the rotor's presence. The midspan rotor flow field was measured using a two-component LDV. Measurements were made from upstream of the rotor to a chord behind the rotor. The distortion of the nozzle wake as it passed through the rotor blade row was determined. The unsteadiness in the rotor flow field was determined. The decay of the rotor wake was also characterized.

  20. Investigation of Magnetic Field Geometry in Exploding Wire Z-Pinches via Proton Deflectometry

    NASA Astrophysics Data System (ADS)

    Mariscal, Derek; Beg, Farhat; Wei, Mingsheng; Chittenden, Jeremy; Presura, Radu

    2012-10-01

    It is often difficult to determine the configuration of B-fields within z-pinch plasma systems. Typical laser probing diagnostics are limited by the critical density, and electrical diagnostics are prone to failure as well as perturbation of the system. The use of proton beams launched by high intensity lasers, and the subsequent tracking of their deflected trajectories, will enable access to field measurements in previously inaccessible plasma densities.The experimental testing of this method is performed at the Nevada Test Facility (NTF) using the 10J 0.3ps Leopard laser coupled to the 1.6MA ZEBRA pulsed power generator. MHD simulations of the z-pinch plasmas are performed with the 3D resistive MHD code, GORGON. Protons are then injected and tracked through the plasma using the 3D PIC Large Scale Plasma code in order to produce possible proton image plane data. The first computational demonstration of protons propagating through single wire and x-pinch plasmas, along with comparison to recent experimental data will be presented.

  1. The flow field investigations of no load conditions in axial flow fixed-blade turbine

    NASA Astrophysics Data System (ADS)

    Yang, J.; Gao, L.; Wang, Z. W.; Zhou, X. Z.; Xu, H. X.

    2014-03-01

    During the start-up process, the strong instabilities happened at no load operation in a low head axial flow fixed-blade turbine, with strong pressure pulsation and vibration. The rated speed can not reach until guide vane opening to some extent, and stable operation could not be maintained under the rated speed at some head, which had a negative impact on the grid-connected operation of the unit. In order to find the reason of this phenomenon, the unsteady flow field of the whole flow passage at no load conditions was carried out to analyze the detailed fluid field characteristics including the pressure pulsation and force imposed on the runner under three typical heads. The main hydraulic cause of no load conditions instability was described. It is recommended that the power station should try to reduce the no-load running time and go into the high load operation as soon as possible when connected to grid at the rated head. Following the recommendations, the plant operation practice proved the unstable degree of the unit was reduced greatly during start up and connect to the power grid.

  2. Timing and nature of volcanic particle clusters based on field and numerical investigations

    NASA Astrophysics Data System (ADS)

    Bagheri, Gholamhossein; Rossi, Eduardo; Biass, Sébastien; Bonadonna, Costanza

    2016-11-01

    Aggregation processes are known to play an important role in volcanic particle dispersal and sedimentation. They are also a primary source of uncertainty in ash dispersal forecasting since fundamental questions, such as the timing and deposition dynamics of volcanic aggregates, still remain unanswered. Here, we applied a state-of-the-art combination of field and numerical strategies to characterize volcanic aggregates. We introduce a new category of aggregates observed with high-speed-high-resolution videos, namely cored clusters. Cored clusters are mostly sub-spherical fragile aggregates that have never been observed in the deposits nor on adhesive tape as they typically break at impact with the ground. They consist of a core particle (200-500μm) fully covered by a thick shell of particles < 90μm. The low preservation potential of cored clusters in ash deposits explains the poor documentation in the literature and the low consideration attributed so far. Cored clusters can also better explain the deposition of fine ash in proximal and medial regions and the polymodality observed in many ash deposits. In addition, numerical inversions show how cored clusters can rapidly form within 175s from eruption onset. Finally, our observations represent the first field-based evidence of the so-called rafting effect, in which the sedimentation of coarse ash in cored clusters is delayed due to aggregation.

  3. Investigation of uniformity field generated from freeform lens with UV LED exposure system

    NASA Astrophysics Data System (ADS)

    Ciou, F. Y.; Chen, Y. C.; Pan, C. T.; Lin, P. H.; Lin, P. H.; Hsu, F. T.

    2015-03-01

    In the exposure process, the intensity and uniformity of light in the exposure area directly influenced the precision of products. UV-LED (Ultraviolet Light-Emitting Diode) exposure system was established to reduce the radiation leakage and increase the energy efficiency for energy saving. It is a trend that conventional mercury lamp could be replaced with UV-LED exposure system. This study was based on the law of conservation of energy and law of refraction of optical field distributing on the target plane. With these, a freeform lens with uniform light field of main exposure area could be designed. The light outside the exposure area could be concentrated into the area to improve the intensity of light. The refraction index and UV transmittance of Polydimethylsiloxane (PDMS) is 1.43 at 385 nm wavelength and 85-90%, respectively. The PDMS was used to fabricate the optics lens for UV-LEDs. The average illumination and the uniformity could be obtained by increasing the number of UV-LEDs and the spacing of different arrangement modes. After exposure process with PDMS lens, about 5% inaccuracy was obtained. Comparing to 10% inaccuracy of general exposure system, it shows that it is available to replace conventional exposure lamp with using UV-LEDs.

  4. SMOS after 2 YEARS and a half in orbit

    NASA Astrophysics Data System (ADS)

    Kerr, Y.; Richaume, P.; Wigneron, J.-P.; Waldteufel, P.; Mecklenburg, S.; Cabot, F.; Boutin, J.; Font, J.; Reul, N.

    2012-04-01

    The SMOS (Soil Moisture and Ocean Salinity) satellite was successfully launched in November 2009. This ESA led mission for Earth Observation is dedicated to provide soil moisture over continental surface (with an accuracy goal of 0.04 m3/m3) and ocean salinity. These two geophysical features are important as they control the energy balance between the surface and the atmosphere. Their knowledge at a global scale is of interest for climatic and weather researches in particular in improving models forecasts. The purpose of this communication is to present the mission results after more than two years in orbit as well as some outstanding results already obtained. A special attention will be devoted to level 2 products. Modeling multi-angular brightness temperatures is not straightforward. The radiative model transfer model L-MEB (L-band Microwave Emission) is used over land while different models with different approaches as to the modeling of sea surface roughness are used over ocean surfaces. Over land the approach is based on semi-empirical relationships, adapted to different type of surface. The model computes a dielectric constant leading to surface emissivity. Surface features (roughness, vegetation) are also considered in the models. However, considering SMOS spatial resolution a wide area is seen by the instrument with strong heterogeneity. The L2 soil moisture retrieval scheme takes this into account. Brightness temperatures are computed for every classes composing a working area. A weighted function is applied for the incidence angle and the antenna beam. Once the brightness temperature is computed for the entire working area, the minimizing process starts. If no soil moisture is derived (not attempted or process failed) a dielectric constant is still derived from an simplified modeled (the cardioid model). SMOS data enabled very quickly to infer Sea surface salinity fields. As salinity retrieval is quite challenging, retrieving it enable to assess very

  5. Investigation of fast ion behavior using orbit following Monte-Carlo code in magnetic perturbed field in KSTAR

    NASA Astrophysics Data System (ADS)

    Shinohara, Kouji; Suzuki, Yasuhiro; Kim, Junghee; Kim, Jun Young; Jeon, Young Mu; Bierwage, Andreas; Rhee, Tongnyeol

    2016-11-01

    The fast ion dynamics and the associated heat load on the plasma facing components in the KSTAR tokamak were investigated with the orbit following Monte-Carlo (OFMC) code in several magnetic field configurations and realistic wall geometry. In particular, attention was paid to the effect of resonant magnetic perturbation (RMP) fields. Both the vacuum field approximation as well as the self-consistent field that includes the response of a stationary plasma were considered. In both cases, the magnetic perturbation (MP) is dominated by the toroidal mode number n  =  1, but otherwise its structure is strongly affected by the plasma response. The loss of fast ions increased significantly when the MP field was applied. Most loss particles hit the poloidal limiter structure around the outer mid-plane on the low field side, but the distribution of heat loads across the three limiters varied with the form of the MP. Short-timescale loss of supposedly well-confined co-passing fast ions was also observed. These losses started within a few poloidal transits after the fast ion was born deep inside the plasma on the high-field side of the magnetic axis. In the configuration studied, these losses are facilitated by the combination of two factors: (i) the large magnetic drift of fast ions across a wide range of magnetic surfaces due to a low plasma current, and (ii) resonant interactions between the fast ions and magnetic islands that were induced inside the plasma by the external RMP field. These effects are expected to play an important role in present-day tokamaks.

  6. Smoking Patterns, Attitudes and Motives: Unique Characteristics among 2-Year versus 4-Year College Students

    ERIC Educational Resources Information Center

    Berg, C. J.; An, L. C.; Thomas, J. L.; Lust, K. A.; Sanem, J. R.; Swan, D. W.; Ahluwalia, J. S.

    2011-01-01

    Given the previously documented higher rates of smoking among 2-year college students in comparison with 4-year university students, this study compares smoking patterns, attitudes and motives among 2-year and 4-year college students. Two thousand two hundred and sixty-five undergraduate students aged 18-25 years at a 2-year college and a 4-year…

  7. Investigation of the magnetic anisotropy of silicide films ion-beam synthesized in the external magnetic field

    NASA Astrophysics Data System (ADS)

    Gumarov, G. G.; Petukhov, V. Yu.; Zhikharev, V. A.; Valeev, V. F.; Khaibullin, R. I.

    2009-05-01

    Magnetic-field-assisted ion-beam synthesis was used to produce thin magnetic films. (1 1 1) Si wafers were implanted with 40 keV Fe+ ions up to the fluence of 3 × 1017 cm-2 in the external magnetic field of 4 × 103-16 × 103 A/m. The samples were investigated by Moessbauer spectroscopy, X-ray diffraction and autodyne method. The obtained thin films consisted of ferromagnetic Fe3Si and nonmagnetic FeSi phases. The application of the magnetic field during the implantation led to the pronounced in-plane magnetic anisotropy of the synthesized films. On the basis of the Stoner-Wohlfarth model it was shown that the observed anisotropy is the result of the superposition of magnetocrystalline and induced uniaxial anisotropies.

  8. Tuning electronic structure of SnS2 nanosheets by vertical electric field: a first-principles investigation

    NASA Astrophysics Data System (ADS)

    Guo, Peng; Wang, Tianxing; Xia, Congxin; Jia, Yu

    2016-07-01

    Based on density functional theory, we investigated band gap tuning in transition-metal dichalcogenides SnS2 nanosheets by external electric fields applied perpendicular to the layers. We show that the fundamental band gap value of 2H and 4H SnS2 multilayer structures continuously decreases with increasing strength of applied electric fields, eventually rendering them metallic. We interpret our results in the light of the giant Stark effect and obtain a robust relationship, which is essentially characterized by the interlayer spacing, for the rate of band gap change with applied external field. And it is also valid for monolayer structure, though it need very large electric filed to make the gap change.

  9. Investigating the effect of some parameters of the channel on the characteristics of tunneling carbon nanotube field-effect transistor

    NASA Astrophysics Data System (ADS)

    Valed Karimi, Najmeh; Pourasad, Yaghoub

    2016-08-01

    This paper studies p-i-n tunneling carbon nanotube field-effect transistor to investigate the effect of various parameters of the channel on the characteristics of tunneling carbon nanotube field-effect transistor. Tunneling carbon nanotube field-effect transistor (T-CNTFET) has been simulated using non-equilibrium Green's function (NEGF), and the transmission was conducted through inelastic scattering. Besides the evaluation of device performance, various parameters of the channel were also compared. One of the parameters is considered as the variable, while other parameters of the channel are constant. Then, improved characteristics were discussed by selection of some channel parameters. T-CNTFET with CNT (10, 0) with oxide thickness = 1 nm shows reduced sub-threshold swing (18 mV/decade).

  10. General Overview Over Investigations on Low-Dimensional Carbon-Based Materials in Magnetic Fields above 50 T

    NASA Astrophysics Data System (ADS)

    Portugall, Oliver

    Carbon nanotubes have been intensively investigated in pulsed magnetic fields, mainly to identify the effect of a magnetic flux along the tube axis on the energy band structure. Clear manifestations of the Ahoronov-Bohm effect have been observed in near-infrared absorption measurements on suspended tubes1 as well as in single-tube transport experiments.2 Subsequent studies have shed light on the excitonic nature of optical excitations3 and the magnetic-field induced optical activity of such excitons.4,5 Ongoing activities are focussing on the magnetic alignment dynamics of carbon nanotubes in liquid suspension which has the potential to provide valuable information on their magnetic susceptibility. Experimental investigations on graphene in pulsed magnetic fields are far less advanced than those on carbon nanotubes. This is due to various experimental factors such as intrinsically short integration times for optical experiments and the destructive effect of electromagnetic perturbations on insufficiently screened transport samples. First results have nevertheless been obtained in both cases: Previous absorption measurements6 up to 32 T have been extended to higher fields thereby confirming the characteristic B1/2-dependence of energy levels. Transport measurements, on the other hand, have revealed extended plateaus in the two-terminal resistance of graphene.7 In this talk we gave a complete overview over recent and ongoing experimental investigations on carbon nanotubes and graphene in magnetic fields above 50 T. We referred to the work of several international collaborations including groups from Houston, Los Alamos, Berlin, Oxford, Tokyo, Dublin, Grenoble and Toulouse. Note from Publisher: This article contains the abstract only.

  11. Monte Carlo investigation of transient acoustic fields in partially or completely bounded medium. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Thanedar, B. D.

    1972-01-01

    A simple repetitive calculation was used to investigate what happens to the field in terms of the signal paths of disturbances originating from the energy source. The computation allowed the field to be reconstructed as a function of space and time on a statistical basis. The suggested Monte Carlo method is in response to the need for a numerical method to supplement analytical methods of solution which are only valid when the boundaries have simple shapes, rather than for a medium that is bounded. For the analysis, a suitable model was created from which was developed an algorithm for the estimation of acoustic pressure variations in the region under investigation. The validity of the technique was demonstrated by analysis of simple physical models with the aid of a digital computer. The Monte Carlo method is applicable to a medium which is homogeneous and is enclosed by either rectangular or curved boundaries.

  12. Flow field investigation of atmospheric braking for high drag vehicles with forward facing jets. [in spacecraft entry

    NASA Technical Reports Server (NTRS)

    Grenich, A. F.; Woods, W. C.

    1981-01-01

    Flow field phenomena associated with a supersonic jet issuing upstream into a hypervelocity flow field were investigated experimentally in support of a new space vehicle aerobraking concept developed by Boeing for Orbital Transfer Vehicles (OTV's). Tests were made on OTV models in the NASA Langley 22 in., Mach 20 helium tunnel with jet exit Mach numbers from 1.0 to 6.18 and ballute half angles of 45 and 60 deg. Force data were taken at zero angle of attack to determine the effect of ballute angle, jet Mach number and jet flow rate on vehicle drag. Bow shock structures were examined in terms of flow steadiness to define acceptable jet flow rate regimes for use in drag modulation. Limited tests were made to obtain pressure and temperature distributions around the ballute and to determine the ballute center of pressure. Test results are presented and discussed relative to OTV application and similar previous experimental investigations.

  13. Thematic Mapper and field investigations at the intersection of the Death Valley and Garlock fault zones, California

    NASA Technical Reports Server (NTRS)

    Brady, Roland H., III; Cregan, Alan; Clayton, Jeff; Troxel, Bennie W.; Verosub, Kenneth L.; Abrams, Michael

    1989-01-01

    Analysis of processed images and detailed field investigations have provided significant information concerning the late-Pliocene and Quaternary evolution of the intersection of the Garlock and Death Valley fault zones. The imagery was used to determine patterns of sedimentation and age relationships on alluvial fans and to determine the geometry, styles of deformation, and relative ages of movements on major and minor faults in the study area. The field investigation often confirmed the inferences drawn from the images and provided additional tectonic and geomorphologic data about the Quaternary deformation of the region. All the data gathered in the course of this project support the contention that the Garlock fault zone terminates in the Avawatz Mountains and that the Death Valley fault zone continues south of the intersection for at least 50 km, forming the eastern boundary of the Mojave province.

  14. Investigation of temperature fields in supersonic flow behind a backward-facing step

    NASA Astrophysics Data System (ADS)

    Bedarev, I. A.; Goldfeld, M. A.; Zakharova, Yu. V.; Fedorova, N. N.

    2009-09-01

    The results of numerical modelling and experimental investigations of high-enthalpy turbulent flows in the neighborhood of 90-degree backward-facing steps at the Mach numbers M∞ = 2-4 are presented. The experiments were conducted in the hot-shot wind tunnel IT-302M of ITAM SB RAS. The computations were carried out on the basis of the full Favres-averaged Navier — Stokes equations augmented by the Wilcox turbulence model. The temperature factor influence on the flow structure in the separated zone and temperature distributions was investigated numerically for different Mach numbers. The wall temperature is shown to affect significantly the quantity and sizes of recirculation vortices as well as the temperature distribution in the zone of flow separation and reattachment. The computational results are compared with experimental data on the pressure distribution on the model surface and the wave structure of the flow.

  15. Field investigation and analysis of buried pipelines under various seismic environments. Technical report

    SciTech Connect

    Wang, L.R.L.

    1982-08-01

    A research project is proposed in which the behavior of oil, water, sewer, and gas pipelines under various seismic environments, including seismic shaking and large ground deformation would be investigated. It is suggested that the investigation be conducted in the Beijing and Tangshan areas. Three major hazards to underground pipelines are identified: the effect of wave propagation; ground rupture and differential movement along fault lines; and soil liquefaction induced by ground shaking. Ruptures or severe distortions of the pipe are most often associated with fault movements, landslides, or ground squeeze associated with fault zones. A model is presented to evaluate the general longitudinal responses of buried pipelines, both segmented and continuous, subjected to ground shakings and vibrations. The results of these tests will be used to develop aseismic codes for buried pipelines.

  16. An investigation of the performance of a coaxial HPGe detector operating in a magnetic resonance imaging field

    NASA Astrophysics Data System (ADS)

    Harkness, L. J.; Boston, A. J.; Boston, H. C.; Cole, P.; Cresswell, J. R.; Filmer, F.; Jones, M.; Judson, D. S.; Nolan, P. J.; Oxley, D. C.; Sampson, J. A.; Scraggs, D. P.; Slee, M. J.; Bimson, W. E.; Kemp, G. J.; Groves, J.; Headspith, J.; Lazarus, I.; Simpson, J.; Cooper, R. J.

    2011-05-01

    Nuclear medical imaging modalities such as positron emission tomography and single photon emission computed tomography are used to probe physiological functions of the body by detecting gamma rays emitted from biologically targeted radiopharmaceuticals. A system which is capable of simultaneous data acquisition for nuclear medical imaging and magnetic resonance imaging is highly sought after by the medical imaging community. Such a device could provide a more complete medical insight into the functions of the body within a well-defined structural context. However, acquiring simultaneous nuclear/MRI sequences are technically challenging due to the conventional photomultiplier tube readout employed by most existing scintillator detector systems. A promising solution is a nuclear imaging device composed of semiconductor detectors that can be operated with a standard MRI scanner. However, the influence of placing a semiconductor detector such as high purity germanium (HPGe) within or close to the bore of an MRI scanner, where high magnetic fields are present, is not well understood. In this paper, the performance of a HPGe detector operating in a high strength static ( BS) MRI field along with fast switching gradient fields and radiofrequency from the MRI system has been assessed. The influence of the BS field on the energy resolution of the detector has been investigated for various positions and orientations of the detector within the magnetic field. The results have then been interpreted in terms of the influence of the BS field on the charge collection properties. MRI images have been acquired with the detector situated at the entrance of the MRI bore to investigate the effects of simultaneous data acquisition on detector performance and MRI imaging.

  17. Contrastive voicing acquisition in 2-year-old children: Preliminary data

    NASA Astrophysics Data System (ADS)

    Hitchcock, Elaine R.; Koenig, Laura L.

    2004-05-01

    Earlier studies using voice-onset time (VOT) as the acoustic marker of contrastive voicing acquisition in English have differed widely in method and statistical procedures. Research in this area has shown three primary patterns of voicing acquisition for English stop consonants. One report indicates children demonstrate discrete voicing categories with adult-like VOT values as early as 2 years old. Other reports suggest a subperceptual distinction of the voicing contrast, followed by an exaggerated voicing contrast with evidence of more adult-like discrete categories by 3 years old. Still other reports suggest no distinction between the voicing categories until approximately 3 years. This work investigates voicing acquisition in three typically developing, English-speaking 2-year-old children. The subjects were recorded every 2 weeks for 4-6 months. Approximately 15-20 tokens were elicited for four target utterances containing initial /b p t d/. Frequency distribution, measures of central tendency, and skewness will be calculated for every recording session of each child. Discussion will focus on the development of contrastive VOT categories and their stability over time. These data will contribute to our understanding of laryngeal timing for English stop consonants in young children.

  18. Work Plan and Field Sampling Plan Site Investigations Fort Devens, Massachusetts

    DTIC Science & Technology

    1992-02-01

    Sampling Plan Comments received from: U.S. Environmental Protection Agency Note: All comments have been retyped exactly as submitted. RC422 1 February...B-7) re’~cyc’ dpý p f T 1 Site Investigations Work Plan Comments received from: U.S. Environmental Protection Agency U.S. Department of the Interior...Fish and Wildlife Service Massachusetts Department of Environmental Protection Note: All comments have been retyped exactly as submitted. RC316 1 U.S

  19. Field investigation of techniques for remote laser sensing of oceanographic parameters

    NASA Technical Reports Server (NTRS)

    Houghton, W. M.; Exton, R. J.; Gregory, R. W.

    1983-01-01

    A laser fluorosensor, previously studied in the laboratory, was deployed at a pier in lower Chesapeake Bay for field testing. A Q-switched Nd:YAG laser doubled to 532 nm in conjunction with a gated optical multichannel analyzer (OMA) allow spectra with high signal-to-noise ratios to be recorded in full daylight at a distance of 20 m. As a test of the system a study was conducted of the spatial and temporal variations of the phytopigments phycoerythrin and chlorophyll. The phycoerythrin feature was resolved into two components, one attributable to cyanophytes and the other to cryptophytes. A comparison was also made with spectra obtained by the NASA airborne oceanographic lidar (AOL).

  20. Near-field investigations of the Landers earthquake sequence, April to July 1992

    USGS Publications Warehouse

    Sieh, K.; Jones, L.; Hauksson, E.; Hudnut, K.; Eberhart-Phillips, D.; Heaton, T.; Hough, S.; Hutton, K.; Kanamori, H.; Lilje, A.; Lindvall, Scott; McGill, S.F.; Mori, J.; Rubin, C.; Spotila, J.A.; Stock, J.; Thio, H.K.; Treiman, J.; Wernicke, B.; Zachariasen, J.

    1993-01-01

    The Landers earthquake, which had a moment magnitude (Mw) of 7.3, was the largest earthquake to strike the contiguous United States in 40 years. This earthquake resulted from the rupture of five major and many minor right-lateral faults near the southern end of the eastern California shear zone, just north of the San Andreas fault. Its Mw 6.1 preshock and Mw 6.2 aftershock had their own aftershocks and foreshocks. Surficial geological observations are consistent with local and far-field seismologic observations of the earthquake. Large surficial offsets (as great as 6 meters) and a relatively short rupture length (85 kilometers) are consistent with seismological calculations of a high stress drop (200 bars), which is in turn consistent with an apparently long recurrence interval for these faults.

  1. Investigation on cone jetting regimes of liquid droplets subjected to pyroelectric fields induced by laser blasts

    NASA Astrophysics Data System (ADS)

    Gennari, Oriella; Battista, Luigi; Silva, Benjamin; Grilli, Simonetta; Miccio, Lisa; Vespini, Veronica; Coppola, Sara; Orlando, Pierangelo; Aprin, Laurent; Slangen, Pierre; Ferraro, Pietro

    2015-02-01

    Electrical conductivity and viscosity play a major role in the tip jetting behaviour of liquids subjected to electrohydrodynamic (EHD) forces, thus influencing significantly the printing performance. Recently, we developed a nozzle- and electrode-free pyro-EHD system as a versatile alternative to conventional EHD configurations and we demonstrated different applications, including inkjet printing and three-dimensional lithography. However, only dielectric fluids have been used in all of those applications. Here, we present an experimental characterization of the pyro-EHD jetting regimes, induced by laser blasts, of sessile drops in case of dielectric and conductive liquids in order to extend the applicability of the system to a wider variety of fields including biochemistry and biotechnology where conductive aqueous solutions are typically used.

  2. Numerical and experimental investigation on flow field characteristics of organ pipe nozzle

    NASA Astrophysics Data System (ADS)

    Fang, Z. L.; Kang, Y.; Wang, X. C.; Li, D.; Hu, Y.; Huang, M.; Y Wang, X.

    2014-03-01

    As a new technology that is developed rapidly in recent decades, water jet technology is widely applied in coal, petroleum, chemical industry, aviation, construction, etc. Self-resonant cavitating jet, by playing cavitation, is capable of great destruction. As a typical kind of self-resonant cavitating nozzle, organ pipe nozzle has its special application. In this paper, the flow field of organ pipe nozzle was numerical simulated. Nozzles with different structures were manufactured according to simulation results; their performances were tested on different driving pressure under the condition of submerging. The results showed that working pressure, cavity length and cavity diameter had influence on the characteristics of organ pipe nozzle and it exited optimum parameters.

  3. Numerical investigation of acoustic field in enclosures: Evaluation of active and reactive components of sound intensity

    NASA Astrophysics Data System (ADS)

    Meissner, Mirosław

    2015-03-01

    The paper focuses on a theoretical description and numerical evaluation of active and reactive components of sound intensity in enclosed spaces. As the study was dedicated to low-frequency room responses, a modal expansion of the sound pressure was used. Numerical simulations have shown that the presence of energy vortices whose size and distribution depend on the character of the room response is a distinctive feature of the active intensity field. When several modes with frequencies close to a source frequency are excited, the vortices within the room are positioned irregularly. However, if the response is determined by one or two dominant modes, a regular distribution of vortices in the room can be observed. The irrotational component of the active intensity was found using the Helmholtz decomposition theorem. As was evidenced by numerical simulations, the suppression of the vortical flow of sound energy in the nearfield permits obtaining a clear image of the sound source.

  4. Supersonic Flow Field Investigation Using a Fiber-optic based Doppler Global Velocimeter

    NASA Technical Reports Server (NTRS)

    Meyers, James F.; Lee, Joseph W.; Fletcher, Mark T.; Cavone, Angelo A.; AscencionGuerreroViramontes, J.

    2006-01-01

    A three-component fiber-optic based Doppler Global Velocimeter was constructed, evaluated and used to measure shock structures about a low-sonic boom model in a Mach 2 flow. The system was designed to have maximum flexibility in its ability to measure flows with restricted optical access and in various facilities. System layout is described along with techniques developed for production supersonic testing. System evaluation in the Unitary Plan Wind Tunnel showed a common acceptance angle of f4 among the three views with velocity measurement resolutions comparable with free-space systems. Flow field measurements of shock structures above a flat plate with an attached ellipsoid-cylinder store and a low-sonic boom model are presented to demonstrate the capabilities of the system during production testing.

  5. Optimal approach to the investigation of the Earth's gravitational field by means of satellite gradiometry.

    NASA Astrophysics Data System (ADS)

    Petrovskaya, M. S.

    The conventional approach to the recovery of the Earth's gravitational field from satellite gradiometry observations is based on constructing, from the start, several boundary value (BV) relations, each of them corresponding to a separate observable component of the gravity gradient (GG) tensor or a certain combination of them. In particular, one of such projects, the ARISTOTELES mission, assumes that only the radial and across-track components are accessible (by technical reasons). The purpose of the present paper is mainly to discuss the principle aspects of the problem of the Earth's potential recovering from satellite gradiometry, to give an optimal formulation of the problem and derive the basic boundary value equation in different forms.

  6. Experimental investigation of the velocity field and skin friction for convecting vortex/boundary layer interactions

    NASA Astrophysics Data System (ADS)

    MacRorie, Michael; Pauley, Wayne R.

    1993-01-01

    The interaction between propagating spanwise vortices and a turbulent boundary layer was studied experimentally. The experimental techniques include hotwire anemometry and smoke visualization. The results focus on the relationship between the passage of vortex structures and the response of the boundary layer in terms of unsteady mean velocity, wall shear, and turbulence quantities. Both positive and negative circulation vortices were studied at three different heights above the test surface. The results indicate that the height of the vortex above the surface has an effect on the wall shear response. However, vortex height and strength are related in this experiment. A phase lag between the passage of the vortex center and the peak wall shear stress response is demonstrated. This phase lag was found to increase with streamwise distance. An examination of the response of the mean and turbulent velocity fields in the boundary layer shows that the phase lag is confined to a region close to the wall.

  7. Investigation into the regional wrench tectonics of inner East Anatolia (Turkey) using potential field data

    NASA Astrophysics Data System (ADS)

    Büyüksaraç, Aydın

    2007-01-01

    The residual aeromagnetic and gravity anomalies of inner East Anatolia, surveyed by the Mineral Research and Exploration (MTA) of Turkey, display complexities. Some faults, which are known and new lineaments, are drawn from maxspot map derived from the location of the horizontal gradient of gravity anomalies. Tectonic lineaments of inner East Anatolia exhibit similarities to the direction of East Anatolian Fault Zone. Anticlockwise rotation, approximately -30°, defined from disorientations of aeromagnetic anomalies. The lineaments obtained from maxspots map produced from the gravity anomalies and disoriented aeromagnetic anomalies are in-line with the mobilistic system revealed by the palaeomagnetic data. These Alpine age continental rotations caused westward wrenching of the global lithosphere and led to significant tectonic reactivation and deformations. GPS measurements, current tectonic knowledge and the results of the evaluation of potential field data were combined in a base map to demonstrate similarities.

  8. Preliminary investigation of scale formation and fluid chemistry at the Dixie Valley Geothermal Field, Nevada

    SciTech Connect

    Bruton, C.J.; Counce, D.; Bergfeld, D.; Goff, F.; Johnson, S.D.; Moore, J.N.; Nimz, G.

    1997-06-27

    The chemistry of geothermal, production, and injection fluids at the Dixie Valley Geothermal Field, Nevada, was characterized to address an ongoing scaling problem and to evaluate the effects of reinjection into the reservoir. Fluids generally followed mixing-dilution trends. Recharge to the Dixie Valley system apparently originates from local sources. The low-pressure brine and injection waters were saturated with respect to amorphous silica, which correlated with the ongoing scaling problem. Local shallow ground water contains about 15% geothermal brine mixed with regional recharge. The elevated Ca, Mg, and HCO{sub 3} content of this water suggests that carbonate precipitation may occur if shallow groundwater is reinjected. Downhole reservoir fluids are close to equilibrium with the latest vein mineral assemblage of wairakite-epidote-quartz-calcite. Reinjection of spent geothermal brine is predicted to affect the region near the wellbore differently than it does the region farther away.

  9. Investigation of urban atmospheric visibility by high-frequency extraction: Model development and field test

    NASA Astrophysics Data System (ADS)

    Luo, Chin-Hsiang; Wen, Che-Yen; Yuan, Chung-Shin; Liaw, Jiun-Jian; Lo, Cho-Ching; Chiu, Shih-Hsuan

    This work investigates atmospheric visibility by employing two statistical processes for high-frequency extraction: Sobel operator and fast Fourier transform (FFT). In replacing the traditional measurement methods for atmospheric visibility, the new approaches can provide accurate digital data urban visibility by establishing the numerical indices. The procedure is illustrated as follows. Digital images of urban areas in Kaohsiung, a city at the south of Taiwan, are analyzed according to brightness. High-frequency components of the image are extracted to calculate the index values by employing the Sobel operator and FFT. Finally, the correlation between each index and the visual range estimated by trained investigators are evaluated. A good correlation between two indices and the values obtained by visual investigation is affirmed by correlation coefficients ( R2), 0.8139 and 0.7797, respectively. Furthermore, both indices are highly correlated with each other ( R2=0.9173). Convenient transmission and the exchangeability of digital images of the real-time landscape facilitate the publication of results on the world wide web (WWW).

  10. Investigation of negative bias temperature instability dependence on fin width of silicon-on-insulator-fin-based field effect transistors

    SciTech Connect

    Young, Chadwin D. Wang, Zhe; Neugroschel, Arnost; Majumdar, Kausik; Matthews, Ken; Hobbs, Chris

    2015-01-21

    The fin width dependence of negative bias temperature instability (NBTI) of double-gate, fin-based p-type Field Effect Transistors (FinFETs) fabricated on silicon-on-insulator (SOI) wafers was investigated. The NBTI degradation increased as the fin width narrowed. To investigate this phenomenon, simulations of pre-stress conditions were employed to determine any differences in gate oxide field, fin band bending, and electric field profile as a function of the fin width. The simulation results were similar at a given gate stress bias, regardless of the fin width, although the threshold voltage was found to increase with decreasing fin width. Thus, the NBTI fin width dependence could not be explained from the pre-stress conditions. Different physics-based degradation models were evaluated using specific fin-based device structures with different biasing schemes to ascertain an appropriate model that best explains the measured NBTI dependence. A plausible cause is an accumulation of electrons that tunnel from the gate during stress into the floating SOI fin body. As the fin narrows, the sidewall device channel moves in closer proximity to the stored electrons, thereby inducing more band bending at the fin/dielectric interface, resulting in a higher electric field and hole concentration in this region during stress, which leads to more degradation. The data obtained in this work provide direct experimental proof of the effect of electron accumulation on the threshold voltage stability in FinFETs.

  11. Experimental investigations of electric current under transverse and longitudinal electric field in uniaxially deformed p-Ge

    NASA Astrophysics Data System (ADS)

    Abramov, A. A.; Akimov, V. I.; Dalakyan, A. T.; Tulupenko, Victor N.; Zaitsev, A. M.; Danilov, S. N.; Firsov, D. A.; Shalygin, V. A.

    1999-11-01

    Comparison between cases of longitudinal and transverse directions of uniaxial pressure and strong electric field, affected the bulk hole germanium, to use it for lasting in far IR region has been carried out. Conclusion about preference of crossed directions is made. Threshold pressure, at which stimulated radiation arises, independence of crystallographic direction, along which external influences are applied, is also discussed. The results of experimental investigations of the crossed directions of uniaxial pressure and electric current are given.

  12. Remedial investigation sampling and analysis plan for J-Field, Aberdeen Proving Ground, Maryland: Volume 2, Quality Assurance Project Plan

    SciTech Connect

    Prasad, S.; Martino, L.; Patton, T.

    1995-03-01

    J-Field encompasses about 460 acres at the southern end of the Gunpowder Neck Peninsula in the Edgewood Area of APG (Figure 2.1). Since World War II, the Edgewood Area of APG has been used to develop, manufacture, test, and destroy chemical agents and munitions. These materials were destroyed at J-Field by open burning and open detonation (OB/OD). For the purposes of this project, J-Field has been divided into eight geographic areas or facilities that are designated as areas of concern (AOCs): the Toxic Burning Pits (TBP), the White Phosphorus Burning Pits (WPP), the Riot Control Burning Pit (RCP), the Robins Point Demolition Ground (RPDG), the Robins Point Tower Site (RPTS), the South Beach Demolition Ground (SBDG), the South Beach Trench (SBT), and the Prototype Building (PB). The scope of this project is to conduct a remedial investigation/feasibility study (RI/FS) and ecological risk assessment to evaluate the impacts of past disposal activities at the J-Field site. Sampling for the RI will be carried out in three stages (I, II, and III) as detailed in the FSP. A phased approach will be used for the J-Field ecological risk assessment (ERA).

  13. Investigation of the longitudinal magnetic field effect on dynamic response of viscoelastic graphene sheet based on sinusoidal shear deformation theory

    NASA Astrophysics Data System (ADS)

    Arani, A. Ghorbanpour; Jalaei, M. H.

    2017-02-01

    This research aims to investigate the influence of a longitudinal magnetic field on the dynamic response of single-layered graphene sheet (SLGS) resting on viscoelastic foundation based on the nonlocal sinusoidal shear deformation theory. The present model is capable of capturing both small scale effect and transverse shear deformation effects of nanoplate, and does not require shear correction factors. The material properties of graphene sheet are assumed orthotropic viscoelastic using Kelvin-Voigt model. Utilizing Hamilton's principle governing equations of motion are derived and solved analytically. The parametric study is conducted, focusing on the remarkable effects of the magnetic field, structural damping, stiffness and damping coefficient of the foundation, nonlocal parameter, aspect ratio and length to thickness ratio on the dynamic response of the SLGS. Results indicate that the longitudinal magnetic field exerted on the SLGS decreases the amplitude of dynamic response. In addition, it is observed that the magnetic field effect on the dynamic response is more distinguished as the nonlocal parameter increases while by increasing the foundation and structural damping coefficients, this effect diminishes. The results of this study can be used in design and manufacturing of nanomechanical devices in the presence of magnetic field as a parametric controller.

  14. Field investigations of brucellosis in cattle and small ruminants in Syria, 1990-1996.

    PubMed

    Darwish, M; Benkirane, A

    2001-12-01

    The authors present the epidemiological status of brucellosis in cattle and small ruminants in Syria from 1990 to 1996, based on laboratory findings at the Brucellosis Centre, Damascus. Initial investigations using the Rose Bengal plate test, the complement fixation test and a miniaturised variant of the slow agglutination test were conducted throughout the country in 1990 and 1991, revealing an overall herd seroprevalence rate of 3.14% in cattle herds and 2.94% in small ruminant flocks. Although partially biased by previous vaccination of young female cattle with S19 vaccine, these figures indicate that brucellosis in cattle is widespread, particularly in the urban governorates (provinces) of Damascus, Aleppo and Suwaydah. Brucellosis seroprevalence in sheep and goats was relatively high in the governorates of Damascus, Aleppo and Dara'a. The results of a second series of investigations, performed between 1992 and 1996, show that herd seroprevalence in cattle decreased steadily from 17.48% in 1992, to 2.59% in 1996, in the Government-owned farms, while seroprevalence increased in the private sector during the same period. The difference may be explained by the restriction of brucellosis vaccination to public farms (although this was far from systematic), combined with partial application of a 'test-and-slaughter' policy. In sheep and goats, brucellosis seroprevalence fluctuated in the two sectors, but was higher in the private sector where husbandry is principally extensive. Bacteriological investigations led to the isolation of Brucella melitensis biovars 2 and 3 in sheep and B. abortus biovar 9 in cattle. Although no specific methodology was employed, particularly with regard to sampling, this study is significant as the first international report of the distribution of brucellosis in Syria. Further, well-structured studies are required, the results of which could be used to plan an appropriate national control programme for brucellosis.

  15. Performance Investigation and Characterization of Scramjet and Dual-Mode Scramjet Flow-Fields

    NASA Technical Reports Server (NTRS)

    Riggins, David W.

    2000-01-01

    The following compilation documents significant deliverables under this grant. Note that this summary is extracted from a larger report provided to the Hyper-X office last year at the conclusion of the grant. Current status is documented of the ongoing JANNAF (Joint-Army-Navy-NASA-AirForce) Scramjet Test standards activity from the standpoint of the Analysis SubGroup of which the PI was requested by NASA to be chairman. Also included are some representative contributions to date from the Principle investigator relating to this activity.

  16. Pic 2005, a field campaign to investigate low-tropospheric ozone variability in the Pyrenees

    NASA Astrophysics Data System (ADS)

    Gheusi, F.; Ravetta, F.; Delbarre, H.; Tsamalis, C.; Chevalier-Rosso, A.; Leroy, C.; Augustin, P.; Delmas, R.; Ancellet, G.; Athier, G.; Bouchou, P.; Campistron, B.; Cousin, J.-M.; Fourmentin, M.; Meyerfeld, Y.

    2011-08-01

    The Pic 2005 field campaign took place from 13 June to 7 July 2005 close to the high-altitude permanent atmospheric observatory Pic-du-Midi (PDM), situated at 2875 m asl in the French Pyrenees. The experimental set-up combined in situ ground-based observations at PDM with ozone lidar measurements at two lower sites in close vicinity (600 m asl/28 km away, and 2380 m asl/500 m away). Such an experimental configuration is appropriate to address the question of the vertical layering of the chemical atmosphere in a mountain area and above the plain nearby, and how this influences measurements conducted on a mountain summit under the influence of horizontal transport at regional scale, and vertical transport at local scale. Forecast tools made it possible to plan and carry out 6 one-day Intensive Observation Periods (IOPs), mostly in anticyclonic conditions favoring local thermally induced circulations, with and without local pollution in the lower troposphere. It was thus possible to document i) ozone diurnal variations at PDM; ii) correlation between ozone measurements at PDM and their counterparts at the same altitude in the free troposphere; iii) ozone variability in the vicinity of PDM. The field campaign provided direct experimental evidence that at daytime in the encountered conditions (mostly anticyclonic), PDM failed in a large extent to be representative of the troposphere above the surrounding flat areas at similar altitude. First, ozone daily averages at PDM were found lower than their free-tropospheric counterpart. Thermally induced circulations and convection pumping clean air from the rural boundary layer can account qualitatively for ozone depletion observed at PDM during daytime. However the surface measurements do not support the hypothesis of direct lifting of near-surface air masses up to PDM. Thus, mixing with free-tropospheric air, photochemistry and surface deposition in the valleys appear to be needed ingredients to account quantitatively for the

  17. Geologic Investigations Spurred by Analog Testing at the 7504 Cone-SP Mountain Area of the San Francisco Volcanic Field

    NASA Technical Reports Server (NTRS)

    Eppler, Dean B.

    2015-01-01

    The SP Mountain area of the San Francisco Volcanic Field, AZ, has been used as an analog mission development site for NASA since 1998. This area consists of basaltic cinder cones, lava flows and maar craters that have been active since mid-Miocene, with the youngest events occurring within the last 10,000 years. The area has been used because its geologic and topographic resemblance to lunar and Martian terrains provides an ideal venue for testing hardware and science operations practices that might be employed on planetary surfaces, as well as training astronauts in field geology. Analog operations have often led to insights that spurred new scientific investigations. Most recently, an investigation of the 7504 cone was initiated due to perceptions that Apollo-style traverse plans executed during the Desert RATS 2010 mission had characterized the area incorrectly, leading to concerns that the Apollo traverse planning process was scientifically flawed. This investigation revealed a complex history of fissure eruptions of lava and cinders, cinder cone development, a cone-fill-and-spill episode, extensive rheomorphic lava flow initiation and emplacement, and cone sector collapse that led to a final lava flow. This history was not discernible on pre-RATS mission photogeology, although independent analysis of RATS 2010 data and samples develped a "75% complete solution" that validated the pre-RATS mission planning and Apollo traverse planning and execution. The study also pointed out that the development of scientific knowledge with time in a given field area is not linear, but may follow a functional form that rises steeply in the early period of an investigation but flattens out in the later period, asymptotically approaching a theoretical "complete knowledge" point that probably cannot be achieved. This implies that future human missions must be prepared to shift geographic areas of investigation regularly if significant science returns are to be forthcoming.

  18. Geologic Investigations Spurred by Analog Testing at the 7504 Cone-Sp Mountain Area of the San Francisco Volcanic Field

    NASA Astrophysics Data System (ADS)

    Bleacher, J. E.; Eppler, D. B.; Needham, D. H.; Evans, C. A.; Skinner, J. A.; Feng, W.

    2015-12-01

    The SP Mountain area of the San Francisco Volcanic Field, AZ, has been used as an analog mission development site for NASA since 1998. This area consists of basaltic cinder cones, lava flows and maar craters that have been active since mid-Miocene, with the youngest events occurring within the last 10,000 years. The area has been used because its geologic and topographic resemblance to lunar and Martian terrains provides an ideal venue for testing hardware and science operations practices that might be employed on planetary surfaces, as well as training astronauts in field geology. Analog operations have often led to insights that spurred new scientific investigations. Most recently, an investigation of the 7504 cone was initiated due to perceptions that Apollo-style traverse plans executed during the Desert RATS 2010 mission had characterized the area incorrectly, leading to concerns that the Apollo traverse planning process was scientifically flawed. This investigation revealed a complex history of fissure eruptions of lava and cinders, cinder cone development, a cone-fill-and-spill episode, extensive rheomorphic lava flow initiation and emplacement, and cone sector collapse that led to a final lava flow. This history was not discernible on pre-RATS mission photogeology, although independent analysis of RATS 2010 data and samples develped a "75% complete solution" that validated the pre-RATS mission planning and Apollo traverse planning and execution. The study also pointed out that the development of scientific knowledge with time in a given field area is not linear, but may follow a functional form that rises steeply in the early period of an investigation but flattens out in the later period, asymptotically approaching a theoretical "complete knowledge" point that probably cannot be achieved. This implies that future human missions must be prepared to shift geographic areas of investigation regularly if significant science returns are to be forthcoming.

  19. Full-Field Strain Methods for Investigating Failure Mechanisms in Triaxial Braided Composites

    NASA Technical Reports Server (NTRS)

    Littell, Justin D.; Binienda, Wieslaw K.; Goldberg, Robert K.; Roberts, Gary D.

    2008-01-01

    Recent advancements in braiding technology have led to commercially viable manufacturing approaches for making large structures with complex shape out of triaxial braided composite materials. In some cases, the static load capability of structures made using these materials has been higher than expected based on material strength properties measured using standard coupon tests. A more detailed investigation of deformation and failure processes in large-unit-cell-size triaxial braid composites is needed to evaluate the applicability of standard test methods for these materials and to develop alternative testing approaches. This report presents some new techniques that have been developed to investigate local deformation and failure using digital image correlation techniques. The methods were used to measure both local and global strains during standard straight-sided coupon tensile tests on composite materials made with 12- and 24-k yarns and a 0 /+60 /-60 triaxial braid architecture. Local deformation and failure within fiber bundles was observed and correlations were made between these local failures and global composite deformation and strength.

  20. Magma accumulation or second boiling - Investigating the ongoing deformation field at Montserrat, West Indies

    NASA Astrophysics Data System (ADS)

    Collinson, Amy; Neuberg, Jurgen; Pascal, Karen

    2016-04-01

    For over 20 years, Soufriere Hills Volcano, Montserrat has been in a state of volcanic unrest. Intermittent periods of dome building have been punctuated by explosive eruptions and dome collapse events, endangering the lives of the inhabitants of the island. The last episode of active magma extrusion was in February 2010, and the last explosive event (ash venting) in March 2012. Despite a lack of eruptive activity recently, the volcano continues to emit significant volumes of SO2 and shows an ongoing trend of island inflation. Through the aid of three-dimensional numerical modelling, using a finite element method, we explore the potential sources of the ongoing island inflation. We consider both magmatic (dykes and chamber) and tectonic sources. Whilst a magmatic source suggests the possibility for further eruption, a tectonic source may indicate cessation of volcanic activity. We show that a magmatic source is the most likely scenario, and illustrate the effect of different sources (shapes, characters and depths) on the surface displacement. Furthermore, through the inclusion of topographic data, we investigate how the topography may affect the displacement pattern at the surface. We investigate the conflicting scenarios of magma chamber resupply versus second boiling - crystallisation-induced degassing. Based on numerical modelling results, we suggest the required pressurisation is too high for crystallisation-induced degassing to be the dominant process - thereby suggesting magma accumulation may be ongoing. However, we show that second boiling may be a contributing factor, particularly when taking into account the local tectonics and regional stretching.

  1. Investigating physical field effects on the size-dependent dynamic behavior of inhomogeneous nanoscale plates

    NASA Astrophysics Data System (ADS)

    Ebrahimi, Farzad; Reza Barati, Mohammad

    2017-02-01

    This article investigates the thermo-mechanical vibration frequencies of magneto-electro-thermo-elastic functionally graded (METE-FG) nanoplates in the framework of refined four-unknown shear deformation plate theory. The present nanoplate is subjected to various kinds of thermal loads with uniform, linear and nonlinear distributions. The nonlinear distribution is considered as heat conduction and sinusoidal temperature rise. The present refined theory captures the influences of shear deformations without the need for shear correction factors. Thermo-magneto-electro-elastic coefficients of the FG nanoplate vary gradually along the thickness according to the power-law form. The scale coefficient is taken into consideration implementing the nonlocal elasticity of Eringen. The governing equations are derived through Hamilton's principle and are solved analytically. The frequency response is compared with those of previously published data. The obtained results are presented for the thermo-mechanical vibrations of the FG nanobeams to investigate the effects of material graduation, nonlocal parameter, mode number, slenderness ratio and thermal loading in detail. The present study is associated to aerospace, mechanical and nuclear engineering structures which are under thermal loads.

  2. Conformational properties, torsional potential, and vibrational force field for methacryloyl fluoride - An ab initio investigation

    NASA Technical Reports Server (NTRS)

    Laskowski, B. C.; Jaffe, R. L.; Komornicki, A.

    1985-01-01

    The structure, torsional potentials, vibrational spectra, and harmonic force fields for s-cis and s-trans isomers of methacryloyl fluoride are examined to understand the conformational properties of the molecules and their relationship to macroscopic polymer properties. The structure is found to be in good agreement with experiment. It is shown by calculations that the energy difference between the cis and the transisomers is less than 1 kcal/mol at both the split valence and the split valence polarized levels, with the trans form favored. Analysis of the torsional potentials indicates that a rigid rotor model provides a reasonable description of the motion of the COF group in the molecule. The torsional barrier to interconvert the s-trans to the s-cis form is found to be 7.0 kcal/mol. A fit of the data to a three-term Fourier series shows that it is possible to reproduce the experimentally derived barrier, even though a direct determination indicates that the barrier is higher.

  3. Tunable Superconducting Gravity Gradiometer for Mars Climate, Atmosphere, and Gravity Field Investigation

    NASA Technical Reports Server (NTRS)

    Griggs, C. E.; Paik, H. J.; Moody, M. V.; Han, S.-C.; Rowlands, D. D.; Lemoine, F. G.; Shirron, P. J.

    2015-01-01

    We are developing a compact tensor superconducting gravity gradiometer (SGG) for obtaining gravimetric measurements from planetary orbits. A new and innovative design gives a potential sensitivity of approximately 10(sup -4) E Hz(sup - 1/2)( 1 E = 10(sup -9 S(sup -2) in the measurement band up to 0.1 Hz (suitale for short wavelength static gravity) and of approximately 10(sup -4) E Hz(sup - 1/2) in the frequency band less than 1 mHz (for long wavelength time-variable gravity) from the same device with a baseline just over 10 cm. The measurement band and sensitiy can be optimally tuned in-flight during the mission by changing resonance frequencies, which allows meaurements of both static and time-variable gravity fields from the same mission. Significant advances in the technologies needed for space-based cryogenic instruments have been made in the last decade. In particular, the use of cryocoolers will alleviate the previously severe constraint on mission lifetime imposed by the use of liquid helium, enabling mission durations in the 5 - 10 year range.

  4. Velocity field investigation inside a bulb turbine runner using endoscopic PIV measurements

    NASA Astrophysics Data System (ADS)

    Lemay, S.; Aeschlimann, V.; Fraser, R.; Ciocan, G. D.; Deschênes, C.

    2015-06-01

    The flow in the inter-blade channels of a bulb turbine was measured using endoscopic cameras integrated to a stereoscopic particle image velocimetry (S-PIV) system. This paper presents results from the measurement campaign and also provides some key conclusions based on the dataset. The technical aspect of the measurement configuration is addressed. The main focus is on the novelties and challenges brought by the use of endoscopic cameras to achieve S-PIV measurements between the runner blades. For the first time in hydraulic rotating machinery, velocity measurements covered 62 % of a rotor inter-blade flow. After outlining the techniques used, comparison with laser Doppler velocimetry measurements allows assessing the intrusiveness of the endoscopes. Then, some velocity field analyses are shown. First, the rotor-stator interaction is outlined as the influence of the guide vane wakes on the runner flow. The size, localization, strength and dissipation of those structures are inferred from the information coming from measurements. Finally, the PIV data allow the identification of a vortex located near the suction side of the blades and originating from the corner between the leading edge and the hub when operating the bulb turbine at part-load.

  5. Investigating Alfvénic wave propagation in coronal open-field regions

    PubMed Central

    Morton, R. J.; Tomczyk, S.; Pinto, R.

    2015-01-01

    The physical mechanisms behind accelerating solar and stellar winds are a long-standing astrophysical mystery, although recent breakthroughs have come from models invoking the turbulent dissipation of Alfvén waves. The existence of Alfvén waves far from the Sun has been known since the 1970s, and recently the presence of ubiquitous Alfvénic waves throughout the solar atmosphere has been confirmed. However, the presence of atmospheric Alfvénic waves does not, alone, provide sufficient support for wave-based models; the existence of counter-propagating Alfvénic waves is crucial for the development of turbulence. Here, we demonstrate that counter-propagating Alfvénic waves exist in open coronal magnetic fields and reveal key observational insights into the details of their generation, reflection in the upper atmosphere and outward propagation into the solar wind. The results enhance our knowledge of Alfvénic wave propagation in the solar atmosphere, providing support and constraints for some of the recent Alfvén wave turbulence models. PMID:26213234

  6. Experimental investigations of a sphere anemometer: Wind tunnel and field tests

    NASA Astrophysics Data System (ADS)

    Heisselmann, Hendrik; Peinke, Joachim; Hoelling, Michael

    2013-11-01

    In our contribution we will compare the sphere anemometer and two standard sensors for wind energy and meteorology based on results from laboratory and atmospheric measurements. The sphere anemometer is a drag-based sensor for simultaneous wind speed and direction measurements. The new anemometer makes use of the velocity-dependent deflection of a lightweight sphere mounted on top of a flexible tube. The deflection of the sphere is detected by means of a highly sensitive light pointer, as used in atomic force microscopy. This allows for the detection of very small displacements and thus enables a high sensor resolution. In wind tunnel experiments the sphere anemometer, a 3D sonic anemometer and a standard cup anemometer were exposed to a turbulent wind field generated with a so-called active grid. All acquired data was compared to those of a highly resolving hot-wire probe. Moreover, the sphere anemometer and the two reference sensors were installed on two near-shore sites in the German Wadden Sea. Several month of data from these campaigns were analyzed regarding wind speed and direction measurements as well as durability and stability of the new anemometer. The presented work was founded by the German Ministry of the Environment, Nature Conservation and Nuclear Safety.

  7. Field investigation of duct system performance in California light commercial buildings

    SciTech Connect

    Delp, W.W.; Matson, N.E.; Tschudy, E.

    1997-12-09

    This paper discusses field measurements of duct system performance in fifteen systems located in eight northern California buildings. Light commercial buildings, one- and two-story with package roof-top HVAC units, make up approximately 50% of the non-residential building stock in the U.S. Despite this fact little is known about the performance of these package roof-top units and their associated ductwork. These simple systems use similar duct materials and construction techniques as residential systems (which are known to be quite leaky). This paper discusses a study to characterize the buildings, quantify the duct leakage, and analyze the performance of the ductwork in these types of buildings. The study tested fifteen systems in eight different buildings located in northern California. All of these buildings had the ducts located in the cavity between the drop ceiling and the roof deck. In 50% of these buildings, this cavity was functionally outside the building`s air and thermal barriers. The effective leakage area of the ducts in this study was approximately 2.6 times that in residential buildings. This paper looks at the thermal analysis of the ducts, from the viewpoint of efficiency and thermal comfort. This includes the length of a cycle, and whether the fan is always on or if it cycles with the cooling equipment. 66% of the systems had frequent on cycles of less than 10 minutes, resulting in non-steady-state operation.

  8. Influence of hydrogeochemical processes on zero-valent iron reactive barrier performance: A field investigation

    NASA Astrophysics Data System (ADS)

    Liang, Liyuan; Moline, Gerilynn R.; Kamolpornwijit, Wiwat; West, Olivia R.

    2005-08-01

    Geochemical and mineralogical changes were evaluated at a field Fe 0-PRB at the Oak Ridge Y-12 site concerning operation performance during the treatment of U in high NO 3- groundwater. In the 5-year study period, the Fe 0 remained reactive as shown in pore-water monitoring data, where increases in pH and the removal of certain ionic species persisted. However, coring revealed varying degrees of cementation. After 3.8-year treatment, porosity reduction of up to 41.7% was obtained from mineralogical analysis on core samples collected at the upgradient gravel-Fe 0 interface. Elsewhere, Fe 0 filings were loose with some cementation. Fe 0 corrosion and pore volume reduction at this site are more severe due to the presence of NO 3- at a high level. Tracer tests indicate that hydraulic performance deteriorated: the flow distribution was heterogeneous and under the influence of interfacial cementation a large portion of water was diverted around the Fe 0 and transported outside the PRB. Based on the equilibrium reductions of NO 3- and SO 42- by Fe 0 and mineral precipitation, geochemical modeling predicted a maximum of 49% porosity loss for 5 years of operation. Additionally, modeling showed a spatial distribution of mineral precipitate volumes, with the maximum advancing from the interface toward downgradient with time. This study suggests that water quality monitoring, coupled with hydraulic monitoring and geochemical modeling, can provide a low-cost method for assessing PRB performance.

  9. Influence of hydrogeochemical processes on zero-valent iron reactive barrier performance: a field investigation.

    PubMed

    Liang, Liyuan; Moline, Gerilynn R; Kamolpornwijit, Wiwat; West, Olivia R

    2005-08-01

    Geochemical and mineralogical changes were evaluated at a field Fe0-PRB at the Oak Ridge Y-12 site concerning operation performance during the treatment of U in high NO3- groundwater. In the 5-year study period, the Fe0 remained reactive as shown in pore-water monitoring data, where increases in pH and the removal of certain ionic species persisted. However, coring revealed varying degrees of cementation. After 3.8-year treatment, porosity reduction of up to 41.7% was obtained from mineralogical analysis on core samples collected at the upgradient gravel-Fe0 interface. Elsewhere, Fe0 filings were loose with some cementation. Fe0 corrosion and pore volume reduction at this site are more severe due to the presence of NO3- at a high level. Tracer tests indicate that hydraulic performance deteriorated: the flow distribution was heterogeneous and under the influence of interfacial cementation a large portion of water was diverted around the Fe0 and transported outside the PRB. Based on the equilibrium reductions of NO3- and SO4(2-) by Fe0 and mineral precipitation, geochemical modeling predicted a maximum of 49% porosity loss for 5 years of operation. Additionally, modeling showed a spatial distribution of mineral precipitate volumes, with the maximum advancing from the interface toward downgradient with time. This study suggests that water quality monitoring, coupled with hydraulic monitoring and geochemical modeling, can provide a low-cost method for assessing PRB performance.

  10. Influence of hydrogeochemical processes on zero-valent iron reactive barrier performance: a field investigation.

    PubMed

    Liang, Liyuan; Moline, Gerilynn R; Kamolpornwijit, Wiwat; West, Olivia R

    2005-11-01

    Geochemical and mineralogical changes were evaluated at a field Fe0-PRB at the Oak Ridge Y-12 site concerning operation performance during the treatment of U in high NO3- groundwater. In the 5-yr study period, the Fe0 remained reactive as shown in pore water monitoring data, where increases in pH and the removal of certain ionic species persisted. However, coring revealed varying degrees of cementation. After 3.8-yr treatment, porosity reduction of up to 41.7% was obtained from mineralogical analysis on core samples collected at the upgradient gravel-Fe0 interface. Elsewhere, Fe0 filings were loose with some cementation. Fe0 corrosion and pore volume reduction at this site are more severe due to the presence of NO3- at a high level. Tracer tests indicate that hydraulic performance deteriorated: the flow distribution was heterogeneous and under the influence of interfacial cementation a large portion of water was diverted around the Fe0 and transported outside the PRB. Based on the equilibrium reductions of NO3- and SO4(2-) by Fe0 and mineral precipitation, geochemical modeling predicted a maximum of 49% porosity loss for 5 yr of operation. Additionally, modeling showed a spatial distribution of mineral precipitate volumes, with the maximum advancing from the interface toward downgradient with time. This study suggests that water quality monitoring, coupled with hydraulic monitoring and geochemical modeling, can provide a low-cost method for assessing PRB performance.

  11. Investigation of the electric field structure in ISX-B plasmas

    SciTech Connect

    Mathew, J.; Hallock, G.A.; Jennings, W.C.; Hickok, R.L.; Wootton, A.J.; Sigmar, D.J.

    1986-04-01

    Plasma potentials have been measured for the first time in neutral-beam-heated tokamak discharges. Radial potential profiles have been obtained for coinjection, counterinjection, and balanced injection discharges as well as for ohmically heated plasmas in the Impurity Study Experiment (ISX-B) tokamak. Within experimental uncertainties, the measured values of potential are consistent with calculations based on radial momentum balance using experimental values of rotation velocities, density, and ion temperature. The measurements were made using a heavy-ion beam probe, with typical plasma conditions of I/sub p/ approx. = 150 kA, B/sub T/ approx. = 12.3 kG, n-bar/sub e/ approx. = 4 x 10/sup 13/ cm/sup -3/, and P/sub b/ approx. = 0.9 MW. A negative potential well depth of about 1.0 kV was observed in ohmically heated plasmas and increased somewhat for balanced injection. Counterinjection resulted in a significantly larger well depth of approximately 3 to 4 kV, while coinjection showed an outward-pointing electric field in the plasma interior. The particle confinement times of both ions and impurities were observed to improve with counterinjection as compared with coinjection.

  12. Investigation of thermal protection systems effects on viscid and inviscid flow fields for manned entry systems

    NASA Technical Reports Server (NTRS)

    Bartlett, E. P.; Morse, H. L.; Tong, H.

    1971-01-01

    Procedures and methods for predicting aerothermodynamic heating to delta orbiter shuttle vehicles were reviewed. A number of approximate methods were found to be adequate for large scale parameter studies, but are considered inadequate for final design calculations. It is recommended that final design calculations be based on a computer code which accounts for nonequilibrium chemistry, streamline spreading, entropy swallowing, and turbulence. It is further recommended that this code be developed with the intent that it can be directly coupled with an exact inviscid flow field calculation when the latter becomes available. A nonsimilar, equilibrium chemistry computer code (BLIMP) was used to evaluate the effects of entropy swallowing, turbulence, and various three dimensional approximations. These solutions were compared with available wind tunnel data. It was found study that, for wind tunnel conditions, the effect of entropy swallowing and three dimensionality are small for laminar boundary layers but entropy swallowing causes a significant increase in turbulent heat transfer. However, it is noted that even small effects (say, 10-20%) may be important for the shuttle reusability concept.

  13. Investigating Alfvénic wave propagation in coronal open-field regions.

    PubMed

    Morton, R J; Tomczyk, S; Pinto, R

    2015-07-27

    The physical mechanisms behind accelerating solar and stellar winds are a long-standing astrophysical mystery, although recent breakthroughs have come from models invoking the turbulent dissipation of Alfvén waves. The existence of Alfvén waves far from the Sun has been known since the 1970s, and recently the presence of ubiquitous Alfvénic waves throughout the solar atmosphere has been confirmed. However, the presence of atmospheric Alfvénic waves does not, alone, provide sufficient support for wave-based models; the existence of counter-propagating Alfvénic waves is crucial for the development of turbulence. Here, we demonstrate that counter-propagating Alfvénic waves exist in open coronal magnetic fields and reveal key observational insights into the details of their generation, reflection in the upper atmosphere and outward propagation into the solar wind. The results enhance our knowledge of Alfvénic wave propagation in the solar atmosphere, providing support and constraints for some of the recent Alfvén wave turbulence models.

  14. Investigation of radiation fields outside the Sub-critical Assembly in Dubna.

    PubMed

    Seltbor, P; Lopatkin, A; Gudowski, W; Shvetsov, V; Polanski, A

    2005-01-01

    The radiation fields outside the planned experimental Sub-critical Assembly in Dubna (SAD) have been studied in order to provide a basis for the design of the concrete shielding that cover the reactor core. The effective doses around the reactor, induced by leakage of neutrons and photons through the shielding, have been determined for a shielding thickness varying from 100 to 200 cm. It was shown that the neutron flux and the effective dose is higher above the shielding than at the side of it, owing to the higher fraction of high-energy spallation neutrons emitted in the direction of the incident beam protons. At the top, the effective dose was found to be -150 microSv s(-1) for a concrete thickness of 100 cm, while -2.5 microSv s(-1) for a concrete thickness of 200 cm. It was also shown that the high-energy neutrons (> 10 MeV), which are created in the proton-induced spallation interactions in the target, contribute for the major part of the effective doses outside the reactor.

  15. Numerical investigation of submarine hydrodynamics and flow field in steady turn

    NASA Astrophysics Data System (ADS)

    Cao, Liu-shuai; Zhu, Jun; Wan, Wen-bin

    2016-03-01

    This paper presents numerical simulations of viscous flow past a submarine model in steady turn by solving the Reynolds-Averaged Navier-Stokes Equations (RANSE) for incompressible, steady flows. The rotating coordinate system was adopted to deal with the rotation problem. The Coriolis force and centrifugal force due to the computation in a bodyfixed rotating frame of reference were treated explicitly and added to momentum equations as source terms. Furthermore, velocities of entrances were coded to give the correct magnitude and direction needed. Two turbulence closure models (TCMs), the RNG κ - ɛ model with wall functions and curvature correction and the Shear Stress Transport (SST) κ - ω model without the use of wall functions, but with curvature correction and low- Re correction were introduced, respectively. Take DARPA SUBOFF model as the test case, a series of drift angle varying between 0° and 16° at a Reynolds number of 6.53×106 undergoing rotating arm test simulations were conducted. The computed forces and moment as a function of drift angle during the steady turn are mostly in close agreement with available experimental data. Though the difference between the pressure coefficients around the hull form was observed, they always show the same trend. It was demonstrated that using sufficiently fine grids and advanced turbulence models will lead to accurate prediction of the flow field as well as the forces and moments on the hull.

  16. Field investigation of arsenic in ceramic pot filter-treated drinking water.

    PubMed

    Archer, A R; Elmore, A C; Bell, E; Rozycki, C

    2011-01-01

    Ceramic pot filters (CPFs) is one of several household water treatment technologies that is used to treat drinking water in developing areas. The filters have the advantage of being able to be manufactured using primarily locally available materials and local labor. However, naturally-occurring arsenic present in the clay used to make the filters has the potential to contaminate the water in excess of the World Health Organization drinking water standard of 0.01 mg/L. A manufacturing facility in Guatemala routinely rinses filters to reduce arsenic concentrations prior to distribution to consumers. A systemic study was performed to evaluate the change in arsenic concentrations with increasing volumes of rinse water. Arsenic field kit results were compared to standard method laboratory results, and dissolved versus suspended arsenic concentrations in CPF-treated water were evaluated. The results of the study suggest that rinsing is an effective means of mitigating arsenic leached from the filters, and that even in the absence of a formal rinsing program, routine consumer use may result in the rapid decline of arsenic concentrations. More importantly, the results indicate that filter manufacturers should give strong consideration to implementing an arsenic testing program.

  17. Scale Dependence of Soil Permeability to Air: Measurement Method and Field Investigation

    SciTech Connect

    Garbesi, K.; Sextro, R.G.; Robinson, Arthur L.; Wooley, J.D.; Owens, J.A.; Nazaroff, W.W.

    1995-11-01

    This work investigates the dependence soil air-permeability on sampling scale in near-surface unsaturated soils. A new dual-probe dynamic pressure technique was developed to measure permeability in situ over different length scales and different spatial orientations in the soil. Soils at three sites were studied using the new technique. Each soil was found to have higher horizontal than vertical permeability. Significant scale dependence of permeability was also observed at each site. Permeability increased by a factor of 20 as sampling scale increased from 0.1 to 2 m in a sand soil vegetated with dry grass, and by a factor of 15 as sampling scale increased from 0.1 to 3.5 m in a sandy loam with mature Coast Live Oak trees (Quercus agrifolia). The results indicate that standard methods of permeability assessment can grossly underestimate advective transport of gas-phase contaminants through soils.

  18. Three-dimensional line-field Fourier domain optical coherence tomography for in vivo dermatological investigation.

    PubMed

    Yasuno, Yoshiaki; Endo, Takashi; Makita, Shuichi; Aoki, Gouki; Itoh, Masahide; Yatagai, Toyohiko

    2006-01-01

    We demonstrate 3-D optical coherence tomography using only 1-D mechanical scanning. This system uses the principle of Fourier domain optical coherence tomography for depth resolution, 1-D imaging for lateral vertical resolution, and mechanical scanning by a galvanometer for lateral horizontal resolution. An in vivo human fingerpad is investigated in three dimensions with an image size of 480 points (vertical) x 300 points (horizontal) x 1024 points (depth), which corresponds to 2.1 x 1.4 x 1.3 mm. The acquisition time for a single cross section is 1 ms and that for a single volume is 10 s. The system sensitivity is 75.6 dB at a probe beam power of 1.1 mW.

  19. Life under extreme energy limitation: a synthesis of laboratory- and field-based investigations.

    PubMed

    Lever, Mark A; Rogers, Karyn L; Lloyd, Karen G; Overmann, Jörg; Schink, Bernhard; Thauer, Rudolf K; Hoehler, Tori M; Jørgensen, Bo Barker

    2015-09-01

    The ability of microorganisms to withstand long periods with extremely low energy input has gained increasing scientific attention in recent years. Starvation experiments in the laboratory have shown that a phylogenetically wide range of microorganisms evolve fitness-enhancing genetic traits within weeks of incubation under low-energy stress. Studies on natural environments that are cut off from new energy supplies over geologic time scales, such as deeply buried sediments, suggest that similar adaptations might mediate survival under energy limitation in the environment. Yet, the extent to which laboratory-based evidence of starvation survival in pure or mixed cultures can be extrapolated to sustained microbial ecosystems in nature remains unclear. In this review, we discuss past investigations on microbial energy requirements and adaptations to energy limitation, identify gaps in our current knowledge, and outline possible future foci of research on life under extreme energy limitation.

  20. Field investigations of winter transmission of eastern equine encephalitis virus in Florida.

    PubMed

    Bingham, Andrea M; Burkett-Cadena, Nathan D; Hassan, Hassan K; McClure, Christopher J W; Unnasch, Thomas R

    2014-10-01

    Studies investigating winter transmission of Eastern equine encephalitis virus (EEEV) were conducted in Hillsborough County, Florida. The virus was detected in Culiseta melanura and Anopheles quadrimaculatus in February 2012 and 2013, respectively. During the winter months, herons were the most important avian hosts for all mosquito species encountered. In collections carried out in the summer of 2011, blood meals taken from herons were still common, but less frequently encountered than in winter, with an increased frequency of mammalian- and reptile-derived meals observed in the summer. Four wading bird species (Black-crowned Night Heron [Nycticorax nycticorax], Yellow-crowned Night Heron [Nyctanassa violacea], Anhinga [Anhinga anhinga], and Great Blue Heron [Ardea herodias]) were most frequently fed upon by Cs. melanura and Culex erraticus, suggesting that these species may participate in maintaining EEEV during the winter in Florida.

  1. Field Investigations of Winter Transmission of Eastern Equine Encephalitis Virus in Florida

    PubMed Central

    Bingham, Andrea M.; Burkett-Cadena, Nathan D.; Hassan, Hassan K.; McClure, Christopher J. W.; Unnasch, Thomas R.

    2014-01-01

    Studies investigating winter transmission of Eastern equine encephalitis virus (EEEV) were conducted in Hillsborough County, Florida. The virus was detected in Culiseta melanura and Anopheles quadrimaculatus in February 2012 and 2013, respectively. During the winter months, herons were the most important avian hosts for all mosquito species encountered. In collections carried out in the summer of 2011, blood meals taken from herons were still common, but less frequently encountered than in winter, with an increased frequency of mammalian- and reptile-derived meals observed in the summer. Four wading bird species (Black-crowned Night Heron [Nycticorax nycticorax], Yellow-crowned Night Heron [Nyctanassa violacea], Anhinga [Anhinga anhinga], and Great Blue Heron [Ardea herodias]) were most frequently fed upon by Cs. melanura and Culex erraticus, suggesting that these species may participate in maintaining EEEV during the winter in Florida. PMID:25070997

  2. Scale Dependence of Soil Permeability to Air: Measurement Method and Field Investigation

    NASA Astrophysics Data System (ADS)

    Garbesi, Karina; Sextro, Richard G.; Robinson, Allen L.; Wooley, John D.; Owens, Jonathan A.; Nazaroff, William W.

    1996-03-01

    This work investigates the dependence of soil permeability to air on sampling scale in near-surface unsaturated soils. A new dual-probe dynamic pressure technique was developed to measure permeability in situ over different length scales and different spatial orientations in the soil. Soils at three sites were studied using the new technique. Each soil was found to have higher horizontal than vertical permeability. Significant scale dependence of permeability was also observed at each site. Permeability increased by a factor of 20 as sampling scale increased from 0.1 to 2 m in a sand soil vegetated with dry grass, and by a factor of 15 as sampling scale increased from 0.1 to 3.5 m in a sandy loam with mature Coast Live Oak trees (Quercus agrifolia). The results indicate that standard methods of permeability assessment can grossly underestimate advective transport of gas phase contaminants through soils.

  3. A field investigation of phreatophyte-induced fluctuations in the water table

    USGS Publications Warehouse

    Butler, J.J.; Kluitenberg, G.J.; Whittemore, D.O.; Loheide, S.P.; Jin, W.; Billinger, M.A.; Zhan, X.

    2007-01-01

    Hydrographs from shallow wells in vegetated riparian zones frequently display a distinctive pattern of diurnal water table fluctuations produced by variations in plant water use. A multisite investigation assessed the major controls on these fluctuations and the ecohydrologic insights that can be gleaned from them. Spatial and temporal variations in the amplitude of the fluctuations are primarily a function of variations in (1) the meteorological drivers of plant water use, (2) vegetation density, type, and vitality, and (3) the specific yield of sediments in the vicinity of the water table. Past hydrologic conditions experienced by the riparian zone vegetation, either in previous years or earlier within the same growing season, are also an important control. Diurnal water table fluctuations can be considered a diagnostic indicator of groundwater consumption by phreatophytes at most sites, so the information embedded within these fluctuations should be more widely exploited in ecohydrologic studies. Copyright 2007 by the American Geophysical Union.

  4. Investigations on dynamics of interacting cavitation bubbles in strong acoustic fields.

    PubMed

    Jiang, Liang; Ge, Han; Liu, Fengbin; Chen, Darong

    2017-01-01

    Given its importance to the dynamics of cavitation bubbles, the mutual interaction between bubbles was carefully investigated in this work. The cavitation noises emitted in different sonication conditions were recorded to study the dynamical behavior of the bubbles. The frequency spectra of the noises suggest that the dispersing state of the bubbles severely influence the oscillations of bubbles, and that the nonlinear feature of the dynamics of cavitation bubbles, imposed by the mutual bubble-bubble interaction, gradually develops with the decrease of the dispersing height. Theoretical analysis shows that the size difference between the interacting bubbles should be responsible for the increase of nonlinearity of the oscillation, and that the decrease of the distance between them could effectively enhance the nonlinear feature of the oscillation of the bubble, both of which agree well with the experimental observation.

  5. Field tests of automatic water-level monitor systems: Technology Development Program: Site Investigation Technology Project

    SciTech Connect

    Campbell, M.D.; Schalla, R.

    1990-10-01

    Groundwater in the aquifer beneath the Hanford Site contains radioactive and other contaminants from deposits in the overlying vadose zone. These contaminants flow with the groundwater into the Columbia River. The rate of contaminant movement toward the river depends on hydraulic gradients resulting from aquifer recharge by process water and other liquid waste. Historically, hydraulic gradients were deduced from water-level measurements made manually using steel tapes. However, frequent or simultaneous measurements essential to proper site characterization and remediation under the Resource Conservation and Recovery Act; Comprehensive Environmental Response, Compensation, and Liability Act; and US Environmental Protection Agency (EPA) have been either too costly or impossible. This investigation was authorized to identify technologies capable of meeting site characterization and remediation requirements with precision suitable to EPA. Therefore, we identified and tested available automatic monitoring systems for cost-effective and timely measurements of aquifer water levels. 5 refs., 9 figs.

  6. Evaluation of some biological tests as parameters for microbial activities in soils. II. Field investigations.

    PubMed

    Abd-El-Malek, Y; Monib, M; Rizk, S G; Shehata, S M

    1976-01-01

    Investigations were designed to study the effect of certain factors on the microbial activities in soil. The parameters, used as an index of the microbial activities, were total bacterial counts, dehydrogenase activity, oxidation of organic carbon, and CO2 evolved/7 days. Bahteem Farm clay soil was examined for determining the effects of depth, type of fertilization, and crop rotation on the microbial activities. It appears that the microbial activities, as indicated by the tested parameters, were more pronounced in the surface 15 cm-layer than in the subsurface layer (15-30 cm). Results of all the parameters tested showed markedly higher increases with farmyard manure than with nitrogenous fertilizer and in the control, without significant differences between the latter two. Moreover, the time of sampling had no effect on the results obtained for all parameters. Different types of rotations did not exert significant variation in total bacterial counts, though more than one crop per year increased the organic carbon content of soil and mostly the dehydrogenase activity, whereas the evolution of CO2 tended to decrease. At Gabal el-Asfar Farm, the effect of irrigation with sewage effluent, for long periods, on the microbial activities of sandy soil was investigated. Sewage water stimulated the total bacteria, raised the dehydrogenase activity, the organic carbon, and the production of CO2. In North El Tahreer and Mariut Sectors, the effect of both the type and age of cultivation on the microbial activities in the calcareous soils were examined. Cultivation raised the figures of all the tested parameters progressively with time of cultivation. It was also noticed that crops exerted more beneficial effects on microbial activities than orchards, and the dehydrogenase test was the most reliable parameter to reveal this fact.

  7. Investigating electrokinetics application for in-situ inorganic oil field scale control

    NASA Astrophysics Data System (ADS)

    Hashaykeh, Manal A. I. Albadawi

    Oil well scale formation and deposition is an expensive problem and could be a nightmare for any production engineer if the rate of deposition is rapid as in the case of North Sea oil fields. Inorganic scales accumulate in surface and subsurface equipment causing a reduction in oil production and severe damage for production equipment. The major components of most oil field scale deposits are BaSO4, CaSO4 and SrSO4, which are formed due to incompatible mixing of reservoir formation water and sea water flooded in secondary enhanced oil recovery (EOR) processes. This work focuses on BaSO4 scale as it is one of the toughest scale components to be removed either by chemical means or mechanical means. Scale control methods usually involve complicated treatment using chemical dissolution methods as primary attempt and mechanical scrapping or jetting methods in case of failure of the chemical means. In this work, we devised a novel in-situ scale control method benefiting from the application of direct current (DC) which involves some of the electrokinetic (EK) phenomena. The applications of EK has been proved in our laboratories yielding high efficiency in capturing barium and separating it from sulfate before reaching the production well, thus preventing deposition in the production wellbore or wellbore formation. This objective was evaluated in our lab designed EK apparatus in three parts. In part-1, an 18.5 cm unconsolidated sand core was used which produced inconsistent results. This problem was overcome in part-2, where the porous media involved 46 cm consolidated sandcore. This also partly fulfilled the purpose of upscaling. In part-3, the porous media was extended to a 100 cm spatial distance between the injection and production wells. For all the experiments the reservoir models were made of 125 µm uniform sand particles and followed a final consolidation pressure of 30 psi. The EK-reservoir model contains 2 basic junctions; one of them injecting a 500 ppm SO4 2

  8. [Fusion of field and laboratory studies on the investigation of arsenic].

    PubMed

    Kumagai, Yoshito

    2009-10-01

    Arsenic is ubiquitously distributed in nature throughout Earth's crust and thus the major source of exposure to this metalloid for the general population is naturally polluted drinking water from wells. In East Asia, more than 30 million people are chronically exposed to arsenic. Interestingly, the manifestations of vascular diseases caused by prolonged exposure to arsenic are consistent with those induced by impaired production of endothelium-derived nitric oxide (NO). However, no information has been available on the relation between NO synthesis and chronic arsenic poisoning in humans. A cross-sectional study in an endemic area of chronic arsenic poisoning in Inner Mongolia and experimental animal studies indicated that long-term exposure to arsenic by drinking water causes reduction of NO production in endothelial cells. Subsequent examinations with rabbits showed that decreased NO production during arsenic exposure is, at least in part, due to an "uncoupling" of endothelial NO synthase evoked by decreased levels of (6R)-5,6,7,8-tetrahydro-L-biopterin (BH(4)), a cofactor of the enzyme, leading to endothelial dysfunction. Furthermore, an intervention study in the area of chronic arsenic poisoning in Inner Mongolia suggested that decreased NO levels and peripheral vascular disease in arsenosis patients can be reversed by exposure cessation. In our cellular experiments, we found that arsenic exposure causes adaptive responses against oxidative stress and arsenic cytotoxicity through Nrf2 activation. This review summarizes the results of our recent studies on a fusion of field and laboratory studies on the chronic arsenic poisoning and cellular protection against the metalloid.

  9. Exploring wildfire impact on post-fire runoff water quality: field and laboratory investigation

    NASA Astrophysics Data System (ADS)

    Chen, L.; Acharya, K.; Miller, J.; Berli, M.

    2014-12-01

    Wildfire can have complex effects on physical and chemical properties of soil and post-fire runoff. Water quality issues in the post-fire runoff may have caused catastrophic events in aquatic ecosystem in the Virgin River in Southwestern U.S. To examined the mechanisms of the impact of wildfire on post-fire runoff water quality, field sampling and experiments were conducted on surfaces of various fuel types at a burned site in the Virgin River Watershed. Rainfall simulation tests were performed to generate runoff for water quality test including in-situ DO and pH measurement and laboratory tests on a number of water quality constituents. Soil/ash samples collected from burned surfaces were applied in a laboratory test to produce solutions of different concentrations and DO changes over a 24-hour period were measured. Results confirmed that, for runoff carrying large amounts of sediment or debris, DO values can be substantially reduced to a level close to or lower than 5 mg/L. Fire effects may enhance this trend, but is not necessarily a critical reason for the reduction of DO levels. Laboratory runoff and soil sample analysis show that the post-fire runoff in this watershed may contain a large amount of ammonia (NH3 and NH4+). The concentration of ammonia can be higher than the lethal level to many (if not all) fish species. Fire effects appear to have a significant impact on the ammonia level, which lead to an increase of several times to one order of magnitude in the ammonia concentration in the runoff or soil solution under burned conditions. These results provide information to better understand post-fire water quality in this and similar watersheds.

  10. Phreatic activity on Dominica (Lesser Antilles) - constraints from field investigations and experimental volcanology

    NASA Astrophysics Data System (ADS)

    Mayer, K.; Scheu, B.; Rott, S.; Dingwell, D. B.; Gilg, H. A.

    2015-12-01

    Dominica has one of the highest concentrations of potentially active volcanoes worldwide. In addition to this activity, abundant geothermal manifestations are observed at the surface, especially in the southern part of the Island. The Boiling Lake - Valley of Desolation area is one of the most vigorous ones, hosting hot springs, mud pools, fumaroles, and steam vents. Intense alteration and many, predominantly phreatic explosive features, of varying scales characterize the whole area. The most prominent manifestation of such a phreatic eruption is the Boiling Lake, a high temperature volcanic crater lake and popular tourist attraction. Thus phreatic activity is one of the main volcanic hazards on the Island, to date largely unpredictable in time and magnitude. The conditions causing these eruptions, as well as their trigger mechanisms and magnitude need to be better understood. Field mapping, together with the determination of in situ physical (density, humidity, permeability) and mechanical (strength, stiffness) properties yield the characterization of 3 main active areas with high probabilities for phreatic events. Rapid decompression experiments on samples from these areas gave insights into the fragmentation and ejection behavior. These experiments were flanked by chemical analyses and laboratory characterization (porosity, granulometry). The results show that hydrothermal alteration likely plays a crucial role in determining the probability of explosive events. High temperature acidic fluids, which lead to an intense alteration of the host rock's mineralogy, change the rock properties favoring the formation of a low permeability layer above the vent and increasing the likelihood of the site experiencing a steam-blast eruption. The contribution of these results to constraining the conditions for and the dynamics involved in phreatic eruptions provides valuable input to hazard assessment of these frequently visited sites on Dominica and similar hydrothermally

  11. Field detection capability of immunochemical assays during criminal investigations involving the use of TNT.

    PubMed

    Romolo, Francesco Saverio; Ferri, Elida; Mirasoli, Mara; D'Elia, Marcello; Ripani, Luigi; Peluso, Giuseppe; Risoluti, Roberta; Maiolini, Elisabetta; Girotti, Stefano

    2015-01-01

    The capability to collect timely information about the substances employed on-site at a crime scene is of fundamental importance during scientific investigations in crimes involving the use of explosives. TNT (2,4,6-trinitrotoluene) is one of the most employed explosives in the 20th century. Despite the growing use of improvised explosives, criminal use and access to TNT is not expected to decrease. Immunoassays are simple and selective analytical tests able to detect molecules and their immunoreactions can occur in portable formats for use on-site. This work demonstrates the application of three immunochemical assays capable of detecting TNT to typical forensic samples from experimental tests: an indirect competitive ELISA with chemiluminescent detection (CL-ELISA), a colorimetric lateral flow immunoassay (LFIA) based on colloidal gold nanoparticles label, and a chemiluminescent-LFIA (CL-LFIA). Under optimised working conditions, the LOD of the colorimetric LFIA and CL-LFIA were 1 μg mL(-1) and 0.05 μg mL(-1), respectively. The total analysis time for LFIAs was 15 min. ELISA proved to be a very effective laboratory approach, showing very good sensitivity (LOD of 0.4 ng mL(-1)) and good reproducibility (CV value about 7%). Samples tested included various materials involved in controlled explosions of improvised explosive devices (IEDs), as well as hand swabs collected after TNT handling tests. In the first group of tests, targets covered with six different materials (metal, plastic, cardboard, carpet fabric, wood and adhesive tape) were fixed on top of wooden poles (180 cm high). Samples of soil from the explosion area and different materials covering the targets were collected after each explosion and analysed. In the second group of tests, hand swabs were collected with and without hand washing after volunteers simulated the manipulation of small charges of TNT. The small amount of solution required for each assay allows for several analyses. Results of

  12. A multidisciplinary approach of workload assessment in real-job situations: investigation in the field of aerospace activities.

    PubMed

    Mélan, Claudine; Cascino, Nadine

    2014-01-01

    The present contribution presents two field studies combining tools and methods from cognitive psychology and from occupational psychology in order to perform a thorough investigation of workload in employees. Cognitive load theory proposes to distinguish different load categories of working memory, in a context of instruction. Intrinsic load is inherent to the task, extraneous load refers to components of a learning environment that may be modified to reduce total load, and germane load enables schemas construction and thus efficient learning. We showed previously that this theoretical framework may be successfully extended to working memory tasks in non-instructional designs. Other theoretical models, issued from the field of occupational psychology, account for an individual's perception of work demands or requirements in the context of different psychosocial features of the (work) environment. Combining these approaches is difficult as workload assessment by job-perception questionnaires explore an individual's overall job-perception over a large time-period, whereas cognitive load investigations in working memory tasks are typically performed within short time-periods. We proposed an original methodology enabling investigation of workload and load factors in a comparable time-frame. We report two field studies investigating workload on different shift-phases and between work-shifts, with two custom-made tools. The first one enabled workload assessment by manipulating intrinsic load (task difficulty) and extraneous load (time pressure) in a working-memory task. The second tool was a questionnaire based on the theoretical concepts of work-demands, control, and psychosocial support. Two additional dimensions suspected to contribute to job-perception, i.e., work-family conflicts and availability of human and technical resources were also explored. Results of workload assessments were discussed in light of operators' alertness and job-performance.

  13. Field and flume investigations of the effects of logjams and woody debris on streambed morphology

    NASA Astrophysics Data System (ADS)

    Leung, V.; Montgomery, D. R.; McHenry, M. L.

    2014-12-01

    Interactions among wood debris, fluid flow and sediment transport in rivers are first-order controls on channel morphodynamics, affecting streambed morphology, sediment transport, sediment storage and aquatic habitat. Woody debris increases the hydraulic and topographic complexity in rivers, leading to a greater diversity of aquatic habitats and an increase in the number of large pools that are important fish habitat and breeding grounds. In the past decade, engineered logjams have become an increasingly used tool in river management for simultaneously decreasing the rate of riverbank migration and improving aquatic habitat. Sediment deposits around woody debris build up riverbanks and counteract bank migration caused by erosion. Previous experiments on flow visualization around model woody debris suggest the amount of sediment scour and deposition are primarily related to the presence of roots and the obstructional area of the woody debris. We present the results of fieldwork and sediment transport experiments of streambed morphology around stationary woody debris. Field surveys on the Hoh River and the Elwha River, WA, measure the local streambed morphology around logjams and individual pieces of woody debris. We quantified the amount of local scour and dam-removal related fine sediment deposition around natural and engineered logjams of varying sizes and construction styles, located in different geomorphic settings. We also quantified the amount of local scour around individual pieces of woody debris of varying sizes, geometries and orientations relative to flow. The flume experiments tested the effects of root geometry and log orientation of individual stationary trees on streambed morphology. The flume contained a deformable sediment bed of medium sand. We find that: 1) the presence of roots on woody debris leads to greater areas of both sediment scour and deposition; and 2) the amount of sediment scour and deposition are related to the wood debris cross

  14. A field-based investigation of hydrogeologic impacts on the Lake Chad basin

    NASA Astrophysics Data System (ADS)

    Lee, J.; Goni, I. B.; Grindley, J.; Bura, B.; Mulugeta, V.; Banks, M. L.; Ndunguru, G. G.; Adisa, S. J.; Adegoke, J. O.

    2009-12-01

    Lake Chad was once one of the largest freshwater lakes in the world but has been shrinking dramatically in the last three decades due to poor water resources management and global climate change. The Lake Chad basin has various scientific issues including extending wetlands with invasive species, shortage of water resources, flooding and drought, geomorphologic alteration from desertification, and chemical and biological transition of soil and vegetation. During the summer of 2009, US-Nigeria research team consisting of five professors and eight students from three universities implemented extensive field research along the Hadejia, Jama'are and Komadugu river systems in the Kumadugu-Yobe basin. This basin is a part of Lake Chad basin located in the Sudano-Sahelian zone of northeastern Nigeria. The downstream of the river system discharges water into the lake. Among many issues mentioned above, we focused on groundwater and surface water interactions, recharge potential of soil cover, water quality, and ground temperature. We collected more than a hundred water samples and over seventy soil samples from upstream of the Hadejia-Jama’are river to downstream terminating at the lake. The preliminary analysis shows that the effluent stream pattern at upstream near the Kano river changes at the midstream of Hadejia-Jama’are wetland where the boundary between the impermeable granite basement rock and the permeable Chad formation exists. As the groundwater in the upstream is mostly stored in the fractured aquifer in the basement rock, water table is relatively shallow compared to the one in the mid- and downstream of the river system where Chad formation is dominant. It is observed that the stage of surface water at Hadejia-Jama’are wetland is higher than groundwater and even surrounding ground elevation. This observation may support the expansion of wetland and frequent flooding events during wet season around the midstream area. The amount of discharge at

  15. Near-field investigations of the anisotropic properties of supported lipid bilayers

    NASA Astrophysics Data System (ADS)

    Johnson, Merrell A.

    2011-12-01

    The details of Polarization Modulation Near-Field Scanning Optical Microscopy (PM-NSOM) are presented. How to properly calibrate and align the system is also introduced. A measurement of Muscovite crystal is used to display the capabilities of the setup. Measurements of supported gel state 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) lipid bilayers are presented, emphasizing how it was tooled in exploiting the anisotropic nature of the acyl chains. A discussion of how the effective retardance (DeltaS = 2 pi (ne-no) t /lambda) and the direction of the projection of the acyl chains (φ) are measured simultaneously is given, (where t is the thickness of the bilayer and lambda is the wavelength of light used). It is shown from DeltaS the birefringence (ne-n o) of the bilayer is determined, by assuming the acyl chain tilt with respect to the membrane's normal to be approximately φ ≈ 32 degrees. Time varying experiments show lateral diffusions of ˜ 2x10 -12 (cm2)/s. Temperature controlled PM-NSOM is shown to be a viable way to determine the main phase transition temperature (Tm) for going from the gel to liquid disorder state of supported DPPC bilayers. A change DeltaS ˜ (3.8+/-0.3 mrad) at the main phase transition temperature Tm (≈ 41°C) is observed. This agrees well with previous values of ( ne-no) and translates to an assumed φ ˜ 32 degrees, when T < Tm and 0 when T > Tm. Evidence of supper heating and supper cooling will be presented, along with a discussion of the fluctuations that occur around Tm. Finally it is shown how physical parameters such as the polarizability are extracted from the data. Values of the transverse (alpha t) and longitudinal (alphal) polarizabilites of the acyl chains are shown to be, alphat = 44.2A3 and alphal = 94.4 A3, which correspond well with the theoretical values of a single palmitic acid (C16) alpha t = 25.14 A3 and alpha l = 45.8 A3.

  16. Seismic Investigations of the Murci Geothermal Field (Southern Tuscany, Italy): Preliminary Results

    NASA Astrophysics Data System (ADS)

    Riedel, M.; Alexandrakis, C.; Buske, S.

    2013-12-01

    The Monte Amiata region in the Southern Tuscany, Central Italy, describes a volcanic complex with great significance in terms of the regional fresh water supply, mining and geothermal power generation. Mainly for the latter purpose, the volcanic area of Mt Amiata has been the subject of extensive geological and geophysical research (e.g. Dini et al., 2010 and references therein). The insights from these studies have led to successful geothermal production in the Mt Amiata region since the early 1960s (e.g. Batini et al., 2003). Today's most important reservoirs in this area are the Bagnore and the Piancastagnaio fields which are both operated by the company Enel Green Power. The work presented here deals with the Murci area, another potential reservoir located about 10 km southwest of the Mt Amiata volcanic complex. Therefore, in order to get a more detailed understanding of this area, five reflection seismic profiles were carried out. We have performed on three of them a preliminary depth-migrated images, through Kirchhoff prestack depth migration (KPSDM). The vital point of depth migration algorithms is the accuracy of the velocity model that is used for the backpropagation of the seismic data. Therefore, we derived a suitable 1D starting model from nearby well logs and VSP measurements. In order to remove the large topography effects along the profiles, we then utilized first-arrival tomography for each seismic line. For the following processing we incorporated these 2D tomographic results into our starting model which compensates for static effects and improves the resolution in the near-surface area. The velocity models were then used in the application of KPSDM to the seismic data for each profile, respectively. The resulting preliminary images show a zone of high seismic reflectivity, known as the 'K-horizon' (e.g. Brogi, 2008), and could improve its geological interpretation. These promising results encourage us to proceed with deeper migration velocity

  17. A 2-year longitudinal study of prospective predictors of pathological Internet use in adolescents.

    PubMed

    Strittmatter, Esther; Parzer, Peter; Brunner, Romuald; Fischer, Gloria; Durkee, Tony; Carli, Vladimir; Hoven, Christina W; Wasserman, Camilla; Sarchiapone, Marco; Wasserman, Danuta; Resch, Franz; Kaess, Michael

    2016-07-01

    Longitudinal studies of prospective predictors for pathological Internet use (PIU) in adolescents as well as its course are lacking. This three-wave longitudinal study was conducted within the framework of the European Union-funded project "Saving and Empowering Young Lives in Europe" over a 2-year period. The sample consisted of 1444 students at the baseline investigation (T0); 1202 students after 1 year (T1); and 515 students after 2 years (T2). Structured self-report questionnaires were administered at all three time points. PIU was assessed using the Young Diagnostic Questionnaire (YDQ). In addition, demographic (i.e., gender), social (i.e., parental involvement), psychological (i.e., emotional problems), and Internet use-related factors (i.e., online activities) were assessed as prospective predictors. The prevalence of PIU was 4.3 % at T0, 2.7 % at T1 and 3.1 % at T2. However, only 3 students (0.58 %) had persistent categorical PIU (YDQ score of ≥5) over the 2-year period. In univariate models, a variety of variables that have been previously identified in cross-sectional investigations predicted PIU at T2. However, multivariate regression demonstrated that only previous PIU symptoms and emotional problems were significant predictors of PIU 2 years later (adjusted R (2) 0.23). The stability of categorical PIU in adolescents over 2 years was lower than previously reported. However, current PIU symptoms were the best predictor of later PIU; emotional symptoms also predicted PIU over and above the influence of previous problematic Internet use. Both PIU symptoms and emotional problems may contribute to the vicious cycle that supports the perpetuation of PIU.

  18. Incidence of Primary Mitochondrial Disease in Children Younger Than 2 Years Presenting With Acute Liver Failure

    PubMed Central

    McKiernan, Patrick; Ball, Sarah; Santra, Saikat; Foster, Katherine; Fratter, Carl; Poulton, Joanna; Craig, Kate; McFarland, Robert; Rahman, Shamima; Hargreaves, Iain; Gupte, Girish; Sharif, Khalid; Taylor, Robert W.

    2016-01-01

    ABSTRACT Background: Mitochondrial liver disease (MLD), and in particular mitochondrial DNA (mtDNA) depletion syndrome (MDS) is an important cause of acute liver failure (ALF) in infancy. Early and accurate diagnosis is important because liver transplantation (LT) is often contraindicated. It is unclear which methods are the best to diagnose MLD in the setting of ALF. Objective: The aim of the study was to determine the incidence of MLD in children younger than 2 years with ALF and the utility of routine investigations to detect MLD. Methods: Thirty-nine consecutive infants with ALF were admitted to a single unit from 2009 to 2011. All were extensively investigated using an established protocol. Genes implicated in mitochondrial DNA depletion syndrome were sequenced in all cases and tissue mtDNA copy number measured where available. Results: Five infants (17%) had genetically proven MLD: DGUOK (n = 2), POLG (n = 2), and MPV17 (1). Four of these died, whereas 1 recovered. Two had normal muscle mtDNA copy number and 3 had normal muscle respiratory chain enzymes. An additional 8 children had low hepatic mtDNA copy number but pathogenic mutations were not detected. One of these developed fatal multisystemic disease after LT, whereas 5 who survived remain well without evidence of multisystemic disease up to 6 years later. Magnetic resonance spectroscopy did not distinguish between those with and without MLD. Conclusions: Low liver mtDNA copy number may be a secondary phenomenon in ALF. Screening for mtDNA maintenance gene mutations may be the most efficient way to confirm MLD in ALF in the first 2 years of life. PMID:27482763

  19. Investigation of Beam Instability Under the Effects of Long-Range Transverse Wake Fields in the Berkeley Future Light Source

    SciTech Connect

    Kur, Eugene; Zholents, Alexander A.

    2008-08-31

    An ultra-relativistic charged particle bunch moving through a resonator cavity leaves behind a wake field that will affect subsequent bunches (if the bunch is not ultra-relativistic, the wake field will not be exclusively behind it). If the initial bunch enters the cavity off-axis, it will produce a transverse wake field that can then kick later bunches off the axis. Thus, even bunches that were initially traveling on axis could be displaced and, in turn, produce their own transverse wake fields, affecting following bunches. The offsets obtained by bunches could increase along the bunch train, leading to the so-called multi-bunch beam break-up instability [1]. The purpose of our investigation is to see whether such instability will occur in the superconducting, 1.3 GHz, 2.5GeV linac (see Table 1) planned for the Berkeley future light source (BFLS). We assume an initial steady-state situation established for machine operation; i.e. a continuous process where every bunch follows the same trajectory through the linac, with only small deviations from the axis of the rf structures. We will look at a possible instability arising from a bunch having a small deviation from the established trajectory. Such a deviation would produce a wake field that is slightly different from the one produced by the bunches following the established trajectory. This could lead to subsequent bunches deviating further from the established trajectory. We will assume the deviations are small (at first) and so the difference in the wake field caused by a bunch not traveling along the established trajectory is well approximated by a long-range transverse dipole wake. We are concerned only with deviations from the established trajectory; thus, in our models, a transverse position of zero corresponds to the bunch traveling along the established trajectory. Under this assumption, only the additional long-range transverse dipole wake remains in our models.

  20. The role of high-resolution geomagnetic field models for investigating ionospheric currents at low Earth orbit satellites

    NASA Astrophysics Data System (ADS)

    Stolle, Claudia; Michaelis, Ingo; Rauberg, Jan

    2016-07-01

    Low Earth orbiting geomagnetic satellite missions, such as the Swarm satellite mission, are the only means to monitor and investigate ionospheric currents on a global scale and to make in situ measurements of F region currents. High-precision geomagnetic satellite missions are also able to detect ionospheric currents during quiet-time geomagnetic conditions that only have few nanotesla amplitudes in the magnetic field. An efficient method to isolate the ionospheric signals from satellite magnetic field measurements has been the use of residuals between the observations and predictions from empirical geomagnetic models for other geomagnetic sources, such as the core and lithospheric field or signals from the quiet-time magnetospheric currents. This study aims at highlighting the importance of high-resolution magnetic field models that are able to predict the lithospheric field and that consider the quiet-time magnetosphere for reliably isolating signatures from ionospheric currents during geomagnetically quiet times. The effects on the detection of ionospheric currents arising from neglecting the lithospheric and magnetospheric sources are discussed on the example of four Swarm orbits during very quiet times. The respective orbits show a broad range of typical scenarios, such as strong and weak ionospheric signal (during day- and nighttime, respectively) superimposed over strong and weak lithospheric signals. If predictions from the lithosphere or magnetosphere are not properly considered, the amplitude of the ionospheric currents, such as the midlatitude Sq currents or the equatorial electrojet (EEJ), is modulated by 10-15 % in the examples shown. An analysis from several orbits above the African sector, where the lithospheric field is significant, showed that the peak value of the signatures of the EEJ is in error by 5 % in average when lithospheric contributions are not considered, which is in the range of uncertainties of present empirical models of the EEJ.

  1. Field-scale investigation of infiltration into a compacted soil liner

    USGS Publications Warehouse

    Panno, Samuel V.; Herzog, Beverly L.; Cartwright, Keros; Rehfeldt, Kenneth R.; Krapac, Ivan G.; Hensel, Bruce R.

    1991-01-01

    The Illinois State Geological Survey constructed and instrumented an experimental compacted soil liner. Infiltration of water into the liner has been monitored for two years. The objectives of this investigation were to determine whether a soil liner could be constructed to meet the U.S. EPA's requirement for a saturated hydraulic conductivity of less than or equal to 1.0 ?? 10-7 cm/s, to quantify the areal variability of the hydraulic properties of the liner, and to determine the transit time for water and tracers through the liner. The liner measures 8m ?? 15m ?? 0.9m and was designed and constructed to simulate compacted soil liners built at waste disposal facilities. The surface of the liner was flooded to form a pond on April 12, 1988. Since flooding, infiltration has been monitored with four large-ring (LR) and 32 small-ring (SR) infiltrometers, and a water-balance (WB) method that accounted for total infiltration and evaporation. Ring-infiltrometer and WB data were analyzed using cumulative-infiltration curves to determine infiltration fluxes. The SR data are lognormally distributed, and the SR and LR data form two statistically distinct populations. Small-ring data are nearly identical with WB data; because there is evidence of leakage in the LRs, the SR and WB data are considered more reliable.

  2. Numerical Investigation of Oxygenated and Deoxygenated Blood Flow through a Tapered Stenosed Arteries in Magnetic Field

    PubMed Central

    Akbari Bidokhti, Amin Ali; Khak Rah, Hamid; Vaezi, Siavash; Hooshmand, Payam

    2016-01-01

    Current paper is focused on transient modeling of blood flow through a tapered stenosed arteries surrounded a by solenoid under the presence of heat transfer. The oxygenated and deoxygenated blood are considered here by the Newtonian and Non-Newtonian fluid (power law and Carreau-Yasuda) models. The governing equations of bio magnetic fluid flow for an incompressible, laminar, homogeneous, non-Newtonian are solved by finite volume method with SIMPLE algorithm for structured grid. Both magnetization and electric current source terms are well thought-out in momentum and energy equations. The effects of fluid viscosity model, Hartmann number, and magnetic number on wall shear stress, shearing stress at the stenosis throat and maximum temperature of the system are investigated and are optimized. The current study results are in agreement with some of the existing findings in the literature and are useful in thermal and mechanical design of spatially varying magnets to control the drug delivery and biomagnetic fluid flows through tapered arteries. PMID:27941986

  3. Investigation of a single barrier discharge in submillimeter air gaps. Nonuniform field

    NASA Astrophysics Data System (ADS)

    Bondarenko, P. N.; Emel'yanov, O. A.; Shemet, M. V.

    2014-08-01

    Pulse characteristics of single barrier discharges as well as parameters of charges accumulated on the surface of a dielectric under the atmospheric pressure in the "needle-(0.1-2.0)-mm air gap-polymer barrier-plane" system are investigated. It is found experimentally that for the positive polarity of the needle, the voltage for the discharge initiation is higher than in the case of the negative polarity by ˜25-35%. The reversal of the needle polarity from negative to positive increases the amplitude of the discharge current and the accumulated surface charge by ˜1.5-3 times. For the positive polarity of the needle, the discharge is governed by a streamer mechanism, while for the negative polarity, the discharge is initiated by the formation of a single Trichel pulse. The single pulse regime is observed for the discharge current up to a certain electrode gap d CR. For the positive needle and for air gap width d air > d CR ≈ 1.5 mm, a multipulse burst corona is formed, while for the negative needle and d air > d CR ≈ 0.9 mm, a damped sequence of Trichel pulses evolves in the system.

  4. Numerical investigation of the 3D flow field generated by a self-propelling manta ray

    NASA Astrophysics Data System (ADS)

    Pederzani, Jean-Noel; Haj-Hariri, Hossein

    2010-11-01

    A mixed Lagrangian-Eulerian approach is used to solve the three dimensional Navier-Stokes equation around a self-propelling manta ray. The motion of the manta ray is prescribed using a kinematic model fitted to actual biological data. The dependence of thrust production mechanism on Strouhal and Reynolds numbers is investigated. The vortex core structures are accurately plotted using the λ2 criteria; and a correlation between wake structures and propulsive performance is established. This insight is critical in understanding the key flow features that a bio-inspired autonomous vehicle should reproduce in order to swim efficiently. The solution method is implemented on a block-structured Cartesian grid using a volume of fluid approach. To enhance the computational efficiency, a parallel adaptive mesh refinement technique is used. The present method is validated for the flow around a sphere. A basic station keeping control problem for a pitching and lagging wing is also analyzed to show the capability of the code to aid in controller design and stability analysis.

  5. Numerical Investigation of Oxygenated and Deoxygenated Blood Flow through a Tapered Stenosed Arteries in Magnetic Field.

    PubMed

    Abdollahzadeh Jamalabadi, M Y; Akbari Bidokhti, Amin Ali; Khak Rah, Hamid; Vaezi, Siavash; Hooshmand, Payam

    2016-01-01

    Current paper is focused on transient modeling of blood flow through a tapered stenosed arteries surrounded a by solenoid under the presence of heat transfer. The oxygenated and deoxygenated blood are considered here by the Newtonian and Non-Newtonian fluid (power law and Carreau-Yasuda) models. The governing equations of bio magnetic fluid flow for an incompressible, laminar, homogeneous, non-Newtonian are solved by finite volume method with SIMPLE algorithm for structured grid. Both magnetization and electric current source terms are well thought-out in momentum and energy equations. The effects of fluid viscosity model, Hartmann number, and magnetic number on wall shear stress, shearing stress at the stenosis throat and maximum temperature of the system are investigated and are optimized. The current study results are in agreement with some of the existing findings in the literature and are useful in thermal and mechanical design of spatially varying magnets to control the drug delivery and biomagnetic fluid flows through tapered arteries.

  6. Experimental equipment and procedure for the investigation of semiconductors galvanomagnetic properties in pulsed magnetic fields (in Ukrainian)

    NASA Astrophysics Data System (ADS)

    Savitsky, V. G.; Storchun, P. E.

    Experimental equipment and procedure for the investigation of semiconductors galvanomagnetic properties in pulsed magnetic fields are presented. The experimental equipment consists of the pulsed magnetic field generation system with the amplitude (B_{max}) up to 20T and a data-recording unit. The compensation of pickup noise-voltage induced by the pulsed magnetic field is originaly realized by compensating coils with the variable effective area. The analog amplifiers unit and the integrator that are a part of the data-recording unit form two measuring channels respectively. The output voltage from these channels are switched by the electronic analog commutator to the input of high-speed ADC in the program preset order. The results of analog-to-digital conversion (12 bits+one overflow bit) and channel number (3 bits) are then entered into RAM (2048×16bits) and respectively transmitted to the personal computer when the experiment is completed. The ADC high-speed performance allows for 2048 measurements during 2-2.5 periods of the magnetic field oscillation.}

  7. Construction of a high-resolution moiré interferometer for investigating microstructural displacement fields in materials.

    PubMed

    Goldrein, H T; Rae, P J; Palmer, S J P; Field, J E

    2002-05-15

    A high-magnification moiré interferometer has been constructed with a spatial resolution of the order of 1 microm to measure the local in-plane displacement field associated with a material's microstructure. Laser illumination passes through phase-stepping optics and is delivered to the microscope head by polarization-preserving single-mode optical fibres. The head itself is a compact unit consisting of collimating optics, an objective lens and a charge coupled device (CCD) camera. Thin-phase gratings are cast onto the sample surface with a compliant epoxy resin and coated with ca. 5 nm of gold to enhance the fringe contrast and reduce speckle noise. By switching between the laser illumination and white-light illumination, the underlying microstructure is viewed in exact registration with the measured displacement fields. The application of the instrument is illustrated here by visualization of displacement fields in polymer-bonded explosives (PBXs) during deformation to failure. PBXs are highly filled polymers consisting of up to 95% by weight crystalline explosive bound in a variety of polymeric binders. The mechanical properties of PBXs are highly dependent on the microstructure, and moiré interferometry is an ideal tool for investigating the relationship between the 1-100 microm sized crystals and the displacement fields. Methods such as this are required if computer models of inhomogeneous materials are to be accurately validated.

  8. Geoscience Perspectives in Carbon Sequestration - Educational Training and Research Through Classroom, Field, and Laboratory Investigations

    SciTech Connect

    Wronkiewicz, David; Paul, Varum; Abousif, Alsedik; Ryback, Kyle

    2013-09-30

    The most effective mechanism to limit CO2 release from underground Geologic Carbon Sequestration (GCS) sites over multi-century time scales will be to convert the CO2 into solid carbonate minerals. This report describes the results from four independent research investigations on carbonate mineralization: 1) Colloidal calcite particles forming in Maramec Spring, Missouri, provide a natural analog to evaluate reactions that may occur in a leaking GCS site. The calcite crystals form as a result of physiochemical changes that occur as the spring water rises from a depth of more than 190'. The resultant pressure decrease induces a loss of CO2 from the water, rise in pH, lowering of the solubility of Ca2+ and CO32-, and calcite precipitation. Equilibrium modelling of the spring water resulted in a calculated undersaturated state with respect to calcite. The discontinuity between the observed occurrence of calcite and the model result predicting undersaturated conditions can be explained if bicarbonate ions (HCO3-) are directly involved in precipitation process rather than just carbonate ions (CO32-). 2) Sedimentary rocks in the Oronto Group of the Midcontinent Rift (MCR) system contain an abundance of labile Ca-, Mg-, and Fe-silicate minerals that will neutralize carbonic acid and provide alkaline earth ions for carbonate mineralization. One of the challenges in using MCR rocks for GCS results from their low porosity and permeability. Oronto Group samples were reacted with both CO2-saturated deionized water at 90°C, and a mildly acidic leachant solution in flow-through core-flooding reactor vessels at room temperature. Resulting leachate solutions often exceeded the saturation limit for calcite. Carbonate crystals were also detected in as little as six days of reaction with Oronto Group rocks at 90oC, as well as experiments with forsterite

  9. Investigating the Seismicity and Stress Field of the Truckee -- Lake Tahoe Region, California -- Nevada

    NASA Astrophysics Data System (ADS)

    Seaman, Tyler

    The Lake Tahoe basin is located in a transtensional environment defined by east-dipping range--bounding normal faults, northeast--trending sinistral, and northwest-trending dextral strike-slip faults in the northern Walker Lane deformation belt. This region accommodates as much as 10 mm/yr of dextral shear between the Sierra Nevada and Basin and Range proper, or about 20% of Pacific-North American plate motion. There is abundant seismicity north of Lake Tahoe through the Truckee, California region as opposed to a lack of seismicity associated with the primary normal faults in the Tahoe basin (i.e., West Tahoe fault). This seismicity study is focused on the structural transition zone from north-striking east-dipping Sierran Range bounding normal faults into the northern Walker Lane right-lateral strike-slip domain. Relocations of earthquakes between 2000-2013 are performed by initially applying HYPOINVERSE mean sea level datum and station corrections to produce higher confidence absolute locations as input to HYPODD. HYPODD applies both phase and cross-correlation times for a final set of 'best' event relocations. Relocations of events in the upper brittle crust clearly align along well-imaged, often intersecting, high-angle structures of limited lateral extent. In addition, the local stress field is modeled from 679 manually determined short-period focal mechanism solutions, between 2000 and 2013, located within a fairly dense local seismic network. Short-period focal mechanisms were developed with the HASH algorithm and moment tensor solutions using long-period surface waves and the MTINV code. Resulting solutions show a 9:1 ratio of strike-slip to normal mechanisms in the transition zone study area. Stress inversions using the application SATSI (USGS Spatial And Temporal Stress Inversion) generally show a T-axis oriented primarily E-W that also rotates about 30 degrees counterclockwise, from a WNW-ESE trend to ENE-WSW, moving west to east across the California

  10. Quantitative geophysical investigations at the Diamond M field, Scurry County, Texas

    NASA Astrophysics Data System (ADS)

    Davogustto Cataldo, Oswaldo Ernesto

    The Diamond M field over the Horseshoe Atoll reservoir of west Texas has produced oil since 1942. Even with some 210 well penetrations, complex reservoir compartmentalization has justified an ongoing drilling program with three wells drilled within the last three years. Accurate reservoir characterization requires accurate description of the geometry, geological facies, and petrophysical property distribution ranging from core, through log to the seismic scale. The operator has conducted a careful logging and coring process including dipole sonic logs in addition to acquiring a modern 3D vertical phone - vertical vibrator "P-wave" seismic data volume and an equivalent size 2-component by 2-componet "S-wave" seismic data volume. I analyze these data at different scales, integrating them into a whole. I begin with core analysis of the petrophysical properties of the Horseshoe Atoll reservoir. Measuring porosity, permeability, NMR T2 relaxation and velocities (Vp and Vs) as a function of pressure and find that porosity measurements are consistent when measured with different techniques. When upscaled, these measurements are in excellent agreement with properties measured at the log scale. Together, these measurements provide a lithology-porosity template against which I correlate my seismic P- and S-impedance measurements. Careful examination of P- and S-impedances as well as density from prestack inversion of the P-wave survey of the original time migrated gathers showed lower vertical resolution for S-impedance and density. These latter two parameters are controlled by the far-offset data, which suffers from migration stretch. I address this shortcoming by applying a recently developed non-stretch NMO technique which not only improved the bandwidth of the data but also resulted in inversions that better match the S-impedance and density well log data. The operator hypothesized that 2C by 2C S-wave data would better delineate lithology than conventional P

  11. Preliminary experimental investigation of an X-band Cerenkov-type high power microwave oscillator without guiding magnetic field

    NASA Astrophysics Data System (ADS)

    Guo, Liming; Shu, Ting; Li, Zhiqiang; Ju, Jinchuan; Fang, Xiaoting

    2017-02-01

    Among high power microwave (HPM) generators without guiding magnetic field, Cerenkov-type oscillator is expected to achieve a relatively high efficiency, which has already been realized in X-band in our previous simulation work. This paper presents the preliminary experimental investigations into an X-band Cerenkov-type HPM oscillator without guiding magnetic field. Based on the previous simulation structure, some modifications regarding diode structure were made. Different cathode structures and materials were tested in the experiments. By using a ring-shaped graphite cathode, microwave of about one hundred megawatt level was generated with a pure center frequency of 9.14 GHz, and an efficiency of about 1.3%. As analyzed in the paper, some practical issues reduce the efficiency in experiments, such as real features of the electron beam, probable breakdown regions on the cathode surface which can damage the diode, and so forth.

  12. Investigation of fringing electric field effect on high-resolution blue phase liquid crystal spatial light modulator.

    PubMed

    Yan, Jing; Guo, Zhengbo; Xing, Yufei; Li, Qing

    2015-08-20

    The fringing electric field effect which determines the performance of a high-resolution blue phase liquid crystal spatial light modulator (BPLC-SLM) is investigated by numerical modeling. The BPLC-SLM is polarization-dependent due to the transverse electric field component. The physical mechanism of the phase profile properties for different polarization states is analyzed. General design issues related to the BPLC-SLM configuration and phase profile properties are discussed. Notably, the material parameters and cell gap thickness are both optimized to obtain a low operation voltage (V=26.07  V). This work provides fundamental understanding for the feasibility of low operation voltage and high spatial resolution BPLC-SLM.

  13. SU-C-304-03: Experimental Investigation On the Accuracy of Plastic Scintillation Dosimeters in Small Fields

    SciTech Connect

    Papaconstadopoulos, P; Archambault, L; Seuntjens, J

    2015-06-15

    Purpose: To investigate the accuracy of the Exradin W1 (SI) and of an “in-house” plastic scintillation dosimeter (CHUQ PSD) in small radiation fields. Methods: Output factor (OF) measurements with the W1 and CHUQ PSD were performed for field sizes of 0.5 x 0.5, 1 x 1 and 2 x 2 cm{sup 2}. Both detectors were placed parallel to the central axis (CAX) in water. The spectrum discrimination calibration method was performed in each set-up to account for the Cerenkov (CRV) signal created in the fiber. The OFs were compared to the expected field factors in water derived using i) Monte Carlo (MC) simulations of an accurate accelerator model and ii) microLion (PTW) and D1V diode (SI) OFs. MC-derived correction factors were applied to both the microLion and D1V OFs. For the CHUQ PSD the calibration was repeated in water (// CAX), solid water (perpendicular to CAX) and under a shielded configuration. The signal was collected using a spectrometer (wavelength range = 185–1100 nm). Spectral analysis was performed to evaluate potential changes of the spectral distributions under the various calibration set-up configurations. Results: The W1 OFs presented an over-response for the 0.5 x 0.5 cm{sup 2} in the range of 3 – 4.1% relative to the expected field factor. The CHUQ PSD presented an under-response in the range of 1.5 – 2.7%, without accounting for volume averaging. The CRV spectra under the various calibration procedures appeared similar to each other and only minor changes were observed to the respective OFs. Conclusion: The W1 and CHUQ PSD can be used in small fields down to a 1 x 1 cm{sup 2} field size. Discrepancies were encountered between the two detectors for the smallest field size of 0.5 x 0.5 cm{sup 2} with the CHUQ PSD exhibiting a closer agreement to the expected field factor. Funding sources: 1) Alexander S. Onassis Public Benefit Foundation in Greece and 2) CREATE Medical Physics Research Training Network grant of the Natural Sciences and Engineering

  14. Some learnings from post-event field investigations after the june 2013 floods in the Pyrenees region in France.

    NASA Astrophysics Data System (ADS)

    Payrastre, Olivier; Bonnifait, Laurent; Gaume, Eric; Le Boursicaut, Raphael

    2014-05-01

    In June 2013 catastrophic floods occurred in south of France in the Pyrenees mountainous area. These floods were due to the combination of a high initial discharge due to snowmelt with a significant rainfall event (up to 200mm rainfall), which effects may have been enhanced by an increase of snowmelt. Although the dynamics of this flood are not really similar, some of its features clearly remind what may be observed in the case of flash floods: significant contribution of relatively small watersheds, high solid transport, very limited information on the reality of flood magnitudes due to the small size of catchments contributing to the flood and the destruction of a significant part of the gauging network. This contribution presents the results of a post event field survey conducted in July 2013 in order to document this flood in terms of intensities of hydrologic reactions. The methods used are those described in Gaume et al. [2008, 2009], with a specific focus on the exploitation of videos from weatnesses. The dataset builded includes 31 peak discharge estimates, illustrating the relatively limited intensity of hydrologic reactions if compared to flash floods, but also providing some interesting complements for the consolidation of the methodology used for post-event field investigations: - several opportunities of comparison of the peak discharge estimates obtained from post event field investigations and from the gauging network, showing an overall good coherence - possibility of very significant flow velocities (up to 6 m/s-2) in the specific context observed here (slopes reaching up to 5%). - possibility to get information on flow surface velocities fields from videos provided by weatnesses. - significant influence of space-time rainfall distribution on the features of the flood, stressing the importance of a detailed information on the contribution of the sub-catchments. Gaume E., Borga M., 2008. Post flood field investigations after major flash floods

  15. Investigation on optical and acoustic fields of stimulated Brillouin scattering in As2S3 suspended-core optical fibers

    NASA Astrophysics Data System (ADS)

    Xu, Qiang; Gao, Weiqing; Li, Xue; Ni, Chenquan; Chen, Xiangcai; Chen, Li; Zhang, Wei; Hu, Jigang; Chen, Xiangdong; Yuan, Zijun

    2016-10-01

    The optical and acoustic fields of stimulated Brillouin scattering (SBS) effect in the As2S3 chalcogenide suspended-core microstructured optical fibers (MOFs) are investigated by the finite-element method (FEM). The optical and acoustic fundamental modes at 1550 nm are analyzed with the core diameters of the MOFs varying from 1.0 to 6.0 μm. For each case, the holes of the MOFs are filled with different materials such as trichlormethane (CHCL3), alcohol and water. When the core diameter is 6.0 μm, the maximum peak intensity of the optical fundamental mode is in the case with air holes, while the minimum value is in the case filled with CHCL3. The ratio of difference is 0.66%. The minimum peak intensity of the acoustic fundamental mode is in the case with air holes, while the maximum value is in the case filled with water. The ratio of difference is 0.13%. The same rule occurs in the fiber cores of 4.5, 3.0 and 2.0 μm, where the decreases of 0.97%, 1.48%, 1.94% for optical field and the increases of 0.24%, 0.34%, 0.74% for acoustic field are obtained, respectively. When the core diameter is 1.0 μm, ratios of difference for optical and acoustic fields are much higher than those in the cases of 2.0-6.0 μm, which are 3.55% and 29.13%, respectively. The overlap factors between optical and acoustic fields are calculated, which are changed with the core diameter and the filled material in holes. Our results will be helpful to strengthen or suppress the SBS effect in practical applications.

  16. First Discovery and Investigation of a High-Temperature Hydrothermal Vent Field on the Ultra- Slow Spreading Southwest Indian Ridge

    NASA Astrophysics Data System (ADS)

    Tao, C.; Lin, J.; Guo, S.; Chen, Y. J.; Wu, G.; Han, X.; German, C. R.; Yoerger, D. R.; Zhu, J.; Zhou, N.; Su, X.; Baker, E. T.; Party, S.

    2007-12-01

    Two recent cruises on board the Chinese research vessel Dayang Yihao have successfully investigated the first active hydrothermal vent field to be located along the ultraslow spreading Southwest Indian Ridge (SWIR) and collected hydrothermal sulfide deposit samples. The newly discovered hydrothermal vent field is located on the western end of a magmatically robust spreading segment immediately west of the Gallieni transform fault. Preliminary evidence of strong turbidity anomalies was first measured during a Nov. 2005 cruise on board Dayang Yihao (InterRidge News, vol. 15, pp. 33-34, 2006). Color video footages of the seafloor in the vent-field area were first obtained by a deep-towed video camera in February 2007 during DY115-19 Leg 1, when significant water column turbidity anomalies, noticeable temperature anomalies and methane anomalies were also measured. The vent field was then precisely located, mapped, and photographed in great detail in February- March 2007 during the DY115-19 Leg 2, using the autonomous underwater vehicle ABE of the Woods Hole Oceanographic Institution. A high-resolution bathymetric map, more than 5,000 near-bottom color photos, and several types of water column data were all obtained during three phases of ABE dives. Within the approximately 120-m-long by 100-m-wide hydrothermal field, three groups of active high-temperature vents were identified and color images of black smokers and associated biological communities were obtained from ABE, flying 5 m above the seafloor. Hydrothermal sulfide deposits were then successfully obtained using a TV-guided grab.

  17. First Discovery and Investigation of a High-Temperature Hydrothermal Vent Field on the Ultra- Slow Spreading Southwest Indian Ridge

    NASA Astrophysics Data System (ADS)

    Tao, C.; Lin, J.; Guo, S.; Chen, Y. J.; Wu, G.; Han, X.; German, C. R.; Yoerger, D. R.; Zhu, J.; Zhou, N.; Su, X.; Baker, E. T.; Party, S.

    2004-12-01

    Two recent cruises on board the Chinese research vessel Dayang Yihao have successfully investigated the first active hydrothermal vent field to be located along the ultraslow spreading Southwest Indian Ridge (SWIR) and collected hydrothermal sulfide deposit samples. The newly discovered hydrothermal vent field is located on the western end of a magmatically robust spreading segment immediately west of the Gallieni transform fault. Preliminary evidence of strong turbidity anomalies was first measured during a Nov. 2005 cruise on board Dayang Yihao (InterRidge News, vol. 15, pp. 33-34, 2006). Color video footages of the seafloor in the vent-field area were first obtained by a deep-towed video camera in February 2007 during DY115-19 Leg 1, when significant water column turbidity anomalies, noticeable temperature anomalies and methane anomalies were also measured. The vent field was then precisely located, mapped, and photographed in great detail in February- March 2007 during the DY115-19 Leg 2, using the autonomous underwater vehicle ABE of the Woods Hole Oceanographic Institution. A high-resolution bathymetric map, more than 5,000 near-bottom color photos, and several types of water column data were all obtained during three phases of ABE dives. Within the approximately 120-m-long by 100-m-wide hydrothermal field, three groups of active high-temperature vents were identified and color images of black smokers and associated biological communities were obtained from ABE, flying 5 m above the seafloor. Hydrothermal sulfide deposits were then successfully obtained using a TV-guided grab.

  18. A Coupled Field Multiphysics Modeling Approach to Investigate RF MEMS Switch Failure Modes under Various Operational Conditions

    PubMed Central

    Sadek, Khaled; Lueke, Jonathan; Moussa, Walied

    2009-01-01

    In this paper, the reliability of capacitive shunt RF MEMS switches have been investigated using three dimensional (3D) coupled multiphysics finite element (FE) analysis. The coupled field analysis involved three consecutive multiphysics interactions. The first interaction is characterized as a two-way sequential electromagnetic (EM)-thermal field coupling. The second interaction represented a one-way sequential thermal-structural field coupling. The third interaction portrayed a two-way sequential structural-electrostatic field coupling. An automated substructuring algorithm was utilized to reduce the computational cost of the complicated coupled multiphysics FE analysis. The results of the substructured FE model with coupled field analysis is shown to be in good agreement with the outcome of previously published experimental and numerical studies. The current numerical results indicate that the pull-in voltage and the buckling temperature of the RF switch are functions of the microfabrication residual stress state, the switch operational frequency and the surrounding packaging temperature. Furthermore, the current results point out that by introducing proper mechanical approaches such as corrugated switches and through-holes in the switch membrane, it is possible to achieve reliable pull-in voltages, at various operating temperatures. The performed analysis also shows that by controlling the mean and gradient residual stresses, generated during microfabrication, in conjunction with the proposed mechanical approaches, the power handling capability of RF MEMS switches can be increased, at a wide range of operational frequencies. These design features of RF MEMS switches are of particular importance in applications where a high RF power (frequencies above 10 GHz) and large temperature variations are expected, such as in satellites and airplane condition monitoring. PMID:22408490

  19. Investigation of the process of diamagnetic particle separation in a high-gradient ordered-structure magnetic field

    NASA Astrophysics Data System (ADS)

    Kashevskii, B. É.; Kashevskii, S. É.; Prokhorov, I. V.; Zholud', A. M.

    2011-05-01

    On the basis of the model of a flow-type magnetic filter with a transversely magnetized ordered system of long ferromagnetic rods of rectangular cross section, the process of high-gradient magnetic separation of microscopic diamagnetic particles (potato starch granules of sizes 8-30 μm) from a liquid suspension has been investigated. The registered laws of change in the concentration and size distribution of particles at the suspension outlet from the filter agree with the theoretical conclusions obtained from the analysis of the magnetic field structure and thecharacter of the particle motion in the filter volume.

  20. Investigation of Schottky-Barrier carbon nanotube field-effect transistor by an efficient semi-classical numerical modeling

    NASA Astrophysics Data System (ADS)

    Chen, Changxin; Zhang, Wei; Zhao, Bo; Zhang, Yafei

    2009-12-01

    An efficient semi-classical numerical modeling approach has been developed to simulate the coaxial Schottky-barrier carbon nanotube field-effect transistor (SB-CNTFET). In the modeling, the electrostatic potential of the CNT is obtained by self-consistently solving the analytic expression of CNT carrier distribution and the cylindrical Poisson equation, which significantly enhances the computational efficiency and simultaneously present a result in good agreement to that obtained from the non-equilibrium Green's function (NEGF) formalism based on the first principle. With this method, the effects of the CNT diameter, power supply voltage, thickness and dielectric constant of gate insulator on the device performance are investigated.