Science.gov

Sample records for field large bore

  1. Analytical studies of advanced high-field designs: 20-tesla large-bore superconducting magnets

    SciTech Connect

    Hoard, R.W.; Cornish, D.N.; Scanlan, R.M.; Zbasnik, J.P.; Leber, R.L.; Hickman, R.B.; Lee, J.D.

    1983-09-30

    Several emerging technologies have been combined in a conceptual design study demonstrating the feasibility of producing ultrahigh magnetic fields from large-bore superconducting solenoid magnets. Several designs have been produced that approach peak fields of 20-T in 2.0-m diameter inner bores. The analytical expressions comprising the main features of CONDUCTOR and ADVMAGNET, the two computer programs used in the design of these advanced magnets, are also discussed. These magnets and design techniques will make a paramount contribution to the national mirror-fusion endeavor and to the newly emerging field of nuclear magnetic resonance (NMR) whole-body scanners.

  2. Design of HQ -- a High Field Large Bore Nb3Sn Quadrupole Magnet for LARP

    SciTech Connect

    Felice, H.; Ambrosio, G.; Anerella, M.; Bossert, R.; Caspi, S.; Cheng, D.; Dietderich, D.; Ferracin, P.; Ghosh, A. K.; Hafalia, R.; Hannaford, C. R.; Kashikhin, V.; Schmalze, J.; Prestemon, S.; Sabbi, G. L.; Wanderer, P.; Zlobin, A. V.

    2008-08-17

    In support of the Large Hadron Collider luminosity upgrade, a large bore (120 mm) Nb{sub 3}Sn quadrupole with 15 T peak coil field is being developed within the framework of the US LHC Accelerator Research Program (LARP). The 2-layer design with a 15 mm wide cable is aimed at pre-stress control, alignment and field quality while exploring the magnet performance limits in terms of gradient, forces and stresses. In addition, HQ will determine the magnetic, mechanical, and thermal margins of Nb{sub 3}Sn technology with respect to the requirements of the luminosity upgrade at the LHC.

  3. Behavior of a Field-Reversed Configuration Translated into a Large-Bore Confinement Chamber

    NASA Astrophysics Data System (ADS)

    Sekiguchi, Jun'ichi; Asai, Tomohiko; Takahashi, Tsutomu; Ando, Hirotoshi; Inomoto, Michiaki; Takahashi, Toshiki; Steinhauer, Loren C.

    To demonstrate additional heating and control methods a new field-reversed configuration (FRC) machine called FAT (FRC Amplification via Translation) has begun operations. FAT has a field-reversed theta-pinch (FRTP) plasma source and a large-bore confinement chamber. In the initial experiments on FAT, fast FRC translation and trapping with the translation speeds 70 to 210 km/s has been performed successfully. The typical elongation of the trapped FRC is approximately 3. Disruptive global instability, such as tilt, is not observed.

  4. Bore-sight calibration of the profile laser scanner using a large size exterior calibration field

    NASA Astrophysics Data System (ADS)

    Koska, Bronislav; Křemen, Tomáš; Štroner, Martin

    2014-10-01

    The bore-sight calibration procedure and results of a profile laser scanner using a large size exterior calibration field is presented in the paper. The task is a part of Autonomous Mapping Airship (AMA) project which aims to create s surveying system with specific properties suitable for effective surveying of medium-wide areas (units to tens of square kilometers per a day). As is obvious from the project name an airship is used as a carrier. This vehicle has some specific properties. The most important properties are high carrying capacity (15 kg), long flight time (3 hours), high operating safety and special flight characteristics such as stability of flight, in terms of vibrations, and possibility to flight at low speed. The high carrying capacity enables using of high quality sensors like professional infrared (IR) camera FLIR SC645, high-end visible spectrum (VIS) digital camera and optics in the visible spectrum and tactical grade INSGPS sensor iMAR iTracerRT-F200 and profile laser scanner SICK LD-LRS1000. The calibration method is based on direct laboratory measuring of coordinate offset (lever-arm) and in-flight determination of rotation offsets (bore-sights). The bore-sight determination is based on the minimization of squares of individual point distances from measured planar surfaces.

  5. Large-bore pipe decontamination

    SciTech Connect

    Ebadian, M.A.

    1998-01-01

    The decontamination and decommissioning (D and D) of 1200 buildings within the US Department of Energy-Office of Environmental Management (DOE-EM) Complex will require the disposition of miles of pipe. The disposition of large-bore pipe, in particular, presents difficulties in the area of decontamination and characterization. The pipe is potentially contaminated internally as well as externally. This situation requires a system capable of decontaminating and characterizing both the inside and outside of the pipe. Current decontamination and characterization systems are not designed for application to this geometry, making the direct disposal of piping systems necessary in many cases. The pipe often creates voids in the disposal cell, which requires the pipe to be cut in half or filled with a grout material. These methods are labor intensive and costly to perform on large volumes of pipe. Direct disposal does not take advantage of recycling, which could provide monetary dividends. To facilitate the decontamination and characterization of large-bore piping and thereby reduce the volume of piping required for disposal, a detailed analysis will be conducted to document the pipe remediation problem set; determine potential technologies to solve this remediation problem set; design and laboratory test potential decontamination and characterization technologies; fabricate a prototype system; provide a cost-benefit analysis of the proposed system; and transfer the technology to industry. This report summarizes the activities performed during fiscal year 1997 and describes the planned activities for fiscal year 1998. Accomplishments for FY97 include the development of the applicable and relevant and appropriate regulations, the screening of decontamination and characterization technologies, and the selection and initial design of the decontamination system.

  6. Large Bore Powder Gun Qualification (U)

    SciTech Connect

    Rabern, Donald A.; Valdiviez, Robert

    2012-04-02

    A Large Bore Powder Gun (LBPG) is being designed to enable experimentalists to characterize material behavior outside the capabilities of the NNSS JASPER and LANL TA-55 PF-4 guns. The combination of these three guns will create a capability to conduct impact experiments over a wide range of pressures and shock profiles. The Large Bore Powder Gun will be fielded at the Nevada National Security Site (NNSS) U1a Complex. The Complex is nearly 1000 ft below ground with dedicated drifts for testing, instrumentation, and post-shot entombment. To ensure the reliability, safety, and performance of the LBPG, a qualification plan has been established and documented here. Requirements for the LBPG have been established and documented in WE-14-TR-0065 U A, Large Bore Powder Gun Customer Requirements. The document includes the requirements for the physics experiments, the gun and confinement systems, and operations at NNSS. A detailed description of the requirements is established in that document and is referred to and quoted throughout this document. Two Gun and Confinement Systems will be fielded. The Prototype Gun will be used primarily to characterize the gun and confinement performance and be the primary platform for qualification actions. This gun will also be used to investigate and qualify target and diagnostic modifications through the life of the program (U1a.104 Drift). An identical gun, the Physics Gun, will be fielded for confirmatory and Pu experiments (U1a.102D Drift). Both guns will be qualified for operation. The Gun and Confinement System design will be qualified through analysis, inspection, and testing using the Prototype Gun for the majority of process. The Physics Gun will be qualified through inspection and a limited number of qualification tests to ensure performance and behavior equivalent to the Prototype gun. Figure 1.1 shows the partial configuration of U1a and the locations of the Prototype and Physics Gun/Confinement Systems.

  7. Thermal modeling of bore fields with arbitrarily oriented boreholes

    NASA Astrophysics Data System (ADS)

    Lazzarotto, Alberto

    2016-04-01

    The accurate prediction of the thermal behavior of bore fields for shallow geothermal applications is necessary to carry out a proper design of such systems. A classical methodology to perform this analysis is the so-called g-function method. Most commercial tools implementing this methodology are designed to handle only bore fields configurations with vertical boreholes. This is a limitation since this condition might not apply in a real installation. In a recent development by the author, a semi-analytical method to determine g-function for bore fields with arbitrarily oriented boreholes was introduced. The strategy utilized is based on the idea introduced by Cimmino of representing boreholes as stacked finite line sources. The temperature along these finite lines is calculated by applying the superposition of the effects of each linear heat source in the field. This modeling technique allows to approximate uneven heat distribution along the boreholes which is a key feature for the calculation of g-functions according to Eskilson's boundary conditions. The method has been tested for a few simple configurations and showed results that are similar compare to previous results computed numerically by Eskilson. The method has been then successfully applied to the g-function calculation of an existing large scale highly asymmetrical bore field.

  8. Ultrasonic Phased Array Sound Field Mapping Through Large-Bore Coarse Grained Cast Austenitic Stainless Steel (CASS) Piping Materials

    SciTech Connect

    Cinson, Anthony D.; Crawford, Susan L.; Prowant, Matthew S.; Diaz, Aaron A.; Hathaway, John E.; Anderson, Michael T.

    2012-04-16

    A sound field beam mapping exercise was conducted to further understand the effects of coarse grained microstructures found in CASS materials on phased array ultrasonic wave propagation. Laboratory measurements were made on three CASS specimens with different microstructures; the specimens were polished and etched to reveal measurable grain sizes, shapes and orientations. Three longitudinal, phased array probes were fixed on a specimen's outside diameter with the sound field directed toward one end (face) of the pipe segment over a fixed range of angles. A point receiver was raster scanned over the surface of the specimen face generating a sound field image. A slice of CASS material was then removed from the specimen end and the beam mapping exercise repeated. The sound fields acquired were analyzed for spot size, coherency, and beam redirection. Analyses were conducted between the resulting sound fields and the microstructural characteristics of each specimen.

  9. In-bore instrumentation/diagnostics for large-bore EMLs

    SciTech Connect

    Fernandez, M.J. ); Ager, S.A. ); Hudson, R.D. )

    1991-01-01

    This paper reports on a flying laboratory technique of in-bore diagnostics for large-bore electromagnetic launchers (EMLs). The high pressure, heat, and magnetic flux environment of the EML and its containment structures do not allow easy implementation of conventional diagnostic techniques. Researchers have relied on remote sensing methods, such as B-dot probes (isolated from the bore), for data. The accuracy and relevance of such discrete, remote measurement is somewhat questionable. An in-house program has been initiated to determine the feasibility of making measurement of EML parameters on board a projectile. This technique utilizes off-the-shelf components in a configuration that has been proven effective in measuring projectile acceleration in the bore of propellant driven guns.

  10. Phased Array Ultrasonic Sound Field Mapping through Large-Bore Coarse Grained Cast Austenitic Stainless Steel (CASS) Components

    SciTech Connect

    Crawford, Susan L.; Cinson, Anthony D.; Prowant, Matthew S.; Coble, Jamie B.; Diaz, Aaron A.; Anderson, Michael T.

    2012-09-01

    A sound field beam mapping exercise was conducted to assist in understanding the effects of coarse-grained microstructures found in cast austenitic stainless steel (CASS) materials on acoustic longitudinal wave propagation. Ultrasonic laboratory measurements were made on three specimens representing four different grain structures. Phased array (PA) probes were fixed on each specimen surface and excited in the longitudinal mode at specific angles while a point receiver was scanned in a raster pattern over the end of the specimen, generating a transmitted sound field image. Three probes operating at nominal frequencies of 0.5, 0.8, and 1.0 MHz were used. A 6.4 mm (0.25-in.) thick slice was removed from the specimen end and beam mapping was repeated three times, yielding four full sets of beam images. Data were collected both with a constant part path for each configuration (probe, specimen and slice, angle, etc.) and with a variable part path (fixed position on the surface). The base specimens and slices were then polished and etched to reveal measureable grain microstructures that were compared to the sound field interactions and scattering effects seen in the collected data.

  11. DETAIL OF TWO LARGE BORE HOLES ON TOP OF SOUTH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DETAIL OF TWO LARGE BORE HOLES ON TOP OF SOUTH QUARRY WALL, FACING NORTH - Granite Hill Plantation, Quarry No. 1, South side of State Route 16, 1.3 miles northeast east of Sparta, Sparta, Hancock County, GA

  12. View of four large bore holes on top of quarry ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of four large bore holes on top of quarry wall, facing northeast - Granite Hill Plantation, Quarry No. 4, South side of State Route 16, 1.3 miles northeast east of Sparta, Sparta, Hancock County, GA

  13. VIEW OF PARALLEL LINE OF LARGE BORE HOLES IN NORTHERN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF PARALLEL LINE OF LARGE BORE HOLES IN NORTHERN QUARRY AREA, FACING NORTHEAST - Granite Hill Plantation, Quarry No. 2, South side of State Route 16, 1.3 miles northeast east of Sparta, Sparta, Hancock County, GA

  14. Broad Ion Beam Extraction from Large Bore ECR Ion Source with Cylindrically Comb-Shaped Magnetic Fields Configuration by Feeding Simultaneously 11 to 13 GHz and 2.45 GHz Microwaves

    SciTech Connect

    Kato, Y.; Satani, T.; Matsui, Y.; Watanabe, T.; Sato, F.; Iida, T.; Muramatsu, M.; Kitagawa, A.; Tanaka, K.; Asaji, T.

    2008-11-03

    We tried to enlarge the operation window of an electron cyclotron resonance (ECR) ion source for producing the ECR plasma confined by cylindrically comb-shaped magnetic field, and for extracting the broad ion beam under the low pressures and low microwave powers. The magnetic field by permanent magnets constructs ECR zones at different positions for 2.45 GHz and 11 to 13 GHz microwaves, respectively. According to probe measurements, profiles of plasma density and temperature are different for using each single microwave. We conduct production of ECR plasma by launching simultaneously these two frequency microwaves, and obtain flat profiles of the electron density and the electron temperature. These profiles are not achieved by feeding single frequency microwave. It is found that plasma can be controllable on spatial profiles beyond wide operation window of plasma parameters. We conducted preliminary extracting and forming large bore ion beam from this source. We will make this source a part of tandem type ion source for the first stage. We investigated feasibility and hope to realize the device which has wide range operation window in a single device to produce many kinds of ion beams as like to universal source based on ECR ion source.

  15. Magnetic design of large-bore superconducting quadrupoles for the AHF

    SciTech Connect

    Vladimir S Kashikhin et al.

    2002-08-13

    The Advanced Hydrotest Facility (AHF), under study by LANL, utilizes large-bore superconducting quadrupole magnets to image protons for radiography of fast events. In this concept, 50-GeV proton bunches pass through a thick object and are imaged by a lens system that analyzes the scattered beam to determine object details. Twelve simultaneous views of the object are obtained using multiple beam lines. The lens system uses two types of quadrupoles: a large bore (48-cm beam aperture) for wide field of view imaging and a smaller bore (23 cm aperture) for higher resolution images. The gradients of the magnets are 10.14 T/m and 18.58 T/m with magnetic lengths of 4.3 m and 3.0 m, respectively. The magnets are sufficiently novel to present a design challenge. Evaluation and comparisons were made for various types of magnet design: shell and racetrack coils, cold and warm iron, as well as an active superconducting screen. Nb{sub 3}Sn cable was also considered as an alternative to avoid quenching under high beam-scattering conditions. The superconducting shield concept eliminates the iron core and greatly lessens the cryogenic energy needed for cool down. Several options are discussed and comparisons are made.

  16. Development of 20 T class superconducting magnet with large bore

    SciTech Connect

    Kiyoshi, T.; Inoue, K.; Itoh, K.; Takeuchi, T.; Wada, H.; Maeda, H. ); Kuroishi, K.; Suzuki, F.; Takizawa, T.; Tada, N. )

    1992-01-01

    This paper reports that a 20T class superconducting magnet has been constructed at the National Research Institute for Metals in Japan. Its outermost two of four coils have been operated at 4.2K. Before operating all coils at 1.8K, in saturated superfluid helium, breakdown voltages within the coils were measured. With an inner coil of preliminary design, the system should generate 20.4T in a 44mm free bore.

  17. Ion beams extraction and measurements of plasma parameters on a multi-frequencies microwaves large bore ECRIS with permanent magnets

    SciTech Connect

    Nozaki, Dai; Kiriyama, Ryutaro; Takenaka, Tomoya; Kurisu, Yosuke; Yano, Keisuke; Sato, Fuminobu; Kato, Yushi; Iida, Toshiyuki

    2012-11-06

    We have developed an all-permanent magnet large bore electron cyclotron resonance ion source (ECRIS) for broad ion beam processing. The cylindrically comb-shaped magnetic field configuration is adopted for efficient plasma production and good magnetic confinement. To compensate for disadvantages of fixed magnetic configuration, a traveling wave tube amplifier (TWTA) is used. In the comb-shaped ECRIS, it is difficult to achieve controlling ion beam profiles in the whole inside the chamber by using even single frequency-controllable TWTA (11-13GHz), because of large bore size with all-magnets. We have tried controlling profiles of plasma parameters and then those of extracted ion beams by launching two largely different frequencies simultaneously, i.e., multi-frequencies microwaves. Here we report ion beam profiles and corresponding plasma parameters under various experimental conditions, dependence of ion beams against extraction voltages, and influence of different electrode positions on the electron density profile.

  18. Supraclavicular approach to the subclavian/innominate vein for large-bore central venous catheters.

    PubMed

    Muhm, M; Sunder-Plassmann, G; Apsner, R; Kritzinger, M; Hiesmayr, M; Druml, W

    1997-12-01

    Infraclavicular and internal jugular catheterization are commonly used techniques for hemodialysis access, but may at times be impeded in patients whose anatomy makes cannulation difficult. In an effort to enlarge the spectrum of alternative access sites, we evaluated the supraclavicular approach for large-bore catheters. During an 18-month period we prospectively collected data on success rate and major and minor complications of the supraclavicular access for conventional dialysis catheters as well as Dacron-cuffed tunneled devices in 175 adult patients admitted for various extracorporeal therapies and bone marrow transplantation. Two hundred eight large-bore catheters (99 conventional dialysis catheters, 63 semirigid tunneled Dacron-cuffed catheters, and 46 Hickman catheters) were successfully placed in 164 patients (success rate, 93.8%), 58 (33.1%) of whom had been previously catheterized. Complications included pneumothorax (one patient), arterial puncture (seven patients), and puncture of the thoracic duct (two patients) without sequelae. Postinsertional chest radiographs demonstrated impressive coaxial lie of most catheters. Catheter malpositions occurred only sporadically (1%). Difficulty of introducing the catheter via a placed sheath was rarely observed. There was no clinically significant evidence of catheter-induced venous thrombosis or stenosis. We conclude that the supraclavicular route is an easy and safe first approach for large-bore catheters, as well as a useful alternative to traditional puncture sites for precatheterized and anatomically problematic patients.

  19. MANTA, a novel plug-based vascular closure device for large bore arteriotomies: technical report.

    PubMed

    van Gils, Lennart; Daemen, Joost; Walters, Greg; Sorzano, Todd; Grintz, Todd; Nardone, Sam; Lenzen, Mattie; De Jaegere, Peter P T; Roubin, Gary; Van Mieghem, Nicolas M

    2016-09-18

    Catheter-based interventions have become a less invasive alternative to conventional surgical techniques for a wide array of cardiovascular diseases but often create large arteriotomies. A completely percutaneous technique is attractive as it may reduce the overall complication rate and procedure time. Currently, large bore arteriotomy closure relies on suture-based techniques. Access-site complications are not uncommon and often seem related to closure device failure. The MANTA VCD is a novel collagen-based closure device that specifically targets arteriotomies between 10 and 22 Fr. This technical report discusses the MANTA design concept, practical instructions for use and preliminary clinical experience.

  20. Expect the unexpected: malposition of a large-bore central venous catheter in the urinary bladder.

    PubMed

    Schummer, Wolfram; Schummer, Claudia; Gorse, Andrej; Becker, Udo; Marx, Christiane; Brauer, Martin

    2004-12-01

    We report the case of a femoral vein cannulation in a critically ill trauma patient with the malposition of a large-bore central venous catheter in the urinary bladder. Recognition of the malposition was hampered by bloody tamponade of the bladder in the context of blunt thoraco-abdominal trauma with kidney and liver laceration. A high index of clinical suspicion and the institution of adequate therapy were the key to achieving a successful clinical outcome. We discuss the anatomy of femoral veins, including their close relation to a distended bladder. The application of ultrasound even in emergency situations is stressed.

  1. DEVELOPMENT OF THE LARGE-BORE POWDER GUN FOR THE NEVADA TEST SITE

    SciTech Connect

    Jensen, B.J.; Esparza, J.

    2009-12-28

    Plate-impact experiments on single stage guns provide very planar loading conditions suitable for studying complex phenomena such as phase transitions and material strength, and provide important data useful for constraining and validating predictive models. The objective of the current work was to develop a large-bore (3.5'' or greater) powder gun capable of accelerating projectiles to moderately high velocities (greater than 2.25 km/s) for impact experiments at Nevada Test Site. This gun will span a performance gap between existing gun facilities and provide a means of examining phenomena over a wide range of stresses and time-scales. Advantages of the large-bore gun include the capability to load multiple samples simultaneously, the use of large diameter samples that significantly extend the time duration of the experiment, and minimal tilt (no bow). This new capability required the development of a disposable confinement system that used an explosively driven closure method to prevent contamination from moving up into the gun system. Experimental results for both the gun system and the explosive valve are presented.

  2. Developing of the large-bore powder gun for the Nevada test site

    SciTech Connect

    Jensen, Brian J; Esparza, James S

    2009-01-01

    Plate-impact experiments on single stage guns provide very planar loading conditions suitable for studying complex phenomena such as phase transitions and material strength, and provide important data useful for constraining and validating predictive models. The objective of the current work was to develop a large-bore (3.5-inches or greater) powder gun capable of accelerating projectiles to moderately high velocities (greater than 2.25 km/s) for impact experiments at Nevada Test Site. This gun will span a performance gap between existing gun facilities and provide a means of examining phenomena over a wide range of stresses and time-scales. Advantages of the large-bore gun include the capability to load multiple samples simultaneously, the use of large diameter samples that significantly extend the time duration of the experiment, and minimal tilt (no bow). This new capability required the development of a disposable confinement system that used an explosively driven closure method to prevent contamination from moving up into the gun system. Experimental results for both the gun system and the explosive valve are presented.

  3. Design of a Large Bore 60-T Pulse Magnet for Sandia National Laboratories

    SciTech Connect

    LESCH,B.; LI,L.; PERNAMBUCO-WISE,P.; ROVANG,DEAN C.; SCHNEIDER-MUNTAU,H.J.

    1999-09-23

    The design of a new pulsed magnet system for the generation of intense electron beams is presented. Determined by the required magnetic field profile along the axis, the magnet system consists of two coils (Coil No.1 and No.2) separated by a 32-mm axial gap. Each coil is energized independently. Both coils are internally reinforced with HIM Zylon fiber/epoxy composite. Coil No.1 made with AI-15 Glidcop wire has a bore of 110-mm diameter and is 200-mm long; it is energized by a 1.3-MJ, 13-kV capacitor bank. The magnetic field at the center of this coil is 30 T. Coil No.2 made with CuNb wire has a bore of 45 mm diameter, generates 60 T with a pulse duration of 60 ms, and is powered by a 4.0-MJ, 17.7-kV capacitor bank. We present design criteria, the coupling of the magnets, and the normal and the fault conditions during operation.

  4. Simple method for the generation of multiple homogeneous field volumes inside the bore of superconducting magnets.

    PubMed

    Chou, Ching-Yu; Ferrage, Fabien; Aubert, Guy; Sakellariou, Dimitris

    2015-07-17

    Standard Magnetic Resonance magnets produce a single homogeneous field volume, where the analysis is performed. Nonetheless, several modern applications could benefit from the generation of multiple homogeneous field volumes along the axis and inside the bore of the magnet. In this communication, we propose a straightforward method using a combination of ring structures of permanent magnets in order to cancel the gradient of the stray field in a series of distinct volumes. These concepts were demonstrated numerically on an experimentally measured magnetic field profile. We discuss advantages and limitations of our method and present the key steps required for an experimental validation.

  5. Predicted and experimental performance of large-bore high-speed ball and roller bearings

    NASA Technical Reports Server (NTRS)

    Coe, H. H.

    1983-01-01

    The values of inner and outer race temperature, cage speed, and heat transferred to the lubricant or bearing power loss, calculated using the computer programs Shaberth and Cybean, with the corresponding experimental data for the large bore ball and roller bearings were compared. After the development of computer program, it is important that values calculated using such program are compared with actual bearing performance data to assess the programs predictive capability. Several comprehensive computer programs currently in use are capable of predicting rolling bearing operating and performance characteristics. These programs accept input data of bearing internal geometry, bearing material and lubricant properties, and bearing operating conditions. The programs solve several sets of equations that characterize rolling element bearings. The output produced typically consists of rolling element loads and Hertz stresses, operating contact angles, component speed, heat generation, local temperatures, bearing fatigue life, and power loss. Two of these programs, Shaberth and Cybean were developed.

  6. Optimizing power cylinder lubrication on a large bore natural gas engine

    NASA Astrophysics Data System (ADS)

    Luedeman, Matthew R.

    More than 6000 integral compressors, located along America's natural gas pipelines, pump natural gas across the United States. These compressors are powered by 2-stroke, large bore natural gas burning engines. Lowering the operating costs, reducing the emissions, and ensuring that these engines remain compliant with future emission regulations are the drivers for this study. Substantial research has focused on optimizing efficiency and reducing the fuel derived emissions on this class of engine. However, significantly less research has focused on the effect and reduction of lubricating oil derived emissions. This study evaluates the impact of power cylinder lubricating oil on overall engine emissions with an emphasis on reducing oxidation catalyst poisoning. A traditional power cylinder lubricator was analyzed; power cylinder lubricating oil was found to significantly impact exhaust emissions. Lubricating oil was identified as the primary contributor of particulate matter production in a large bore natural gas engine. The particulate matter was determined to be primarily organic carbon, and most likely direct oil carryover of small oil droplets. The particulate matter production equated to 25% of the injected oil at a nominal power cylinder lubrication rate. In addition, power cylinder friction is considered the primary contributor to friction loss in the internal combustion engine. This study investigates the potential for optimizing power cylinder lubrication by controlling power cylinder injection to occur at the optimal time in the piston cycle. By injecting oil directly into the ring pack, it is believed that emissions, catalyst poisoning, friction, and wear can all be reduced. This report outlines the design and theory of two electronically controlled lubrication systems. Experimental results and evaluation of one of the systems is included.

  7. A methodology for laser diagnostics in large-bore marine two-stroke diesel engines

    NASA Astrophysics Data System (ADS)

    Hult, J.; Mayer, S.

    2013-04-01

    Large two-stroke diesel engines for marine propulsion offer several challenges to successful implementation of the laser diagnostic techniques applied extensively in smaller automotive engines. For this purpose a fully operational large-bore engine has been modified to allow flexible optical access, through 24 optical ports with clear diameters of 40 mm. By mounting the entire optical set-up directly to the engine, effects of the vigorous vibrations and thermal drifts on alignment can be minimized. Wide-angle observation and illumination, as well as relatively large aperture detection, is made possible through mounting of optical modules and relays inside optical ports. This allows positioning of the last optical element within 10 mm from the cylinder wall. Finally, the implementation on a multi-cylinder engine allows for flexible and independent operation of the optically accessible cylinder for testing purposes. The performance of the integrated optical engine and imaging system developed is demonstrated through laser Mie scattering imaging of fuel jet structures, from which information on liquid penetration and spray angles can be deduced. Double pulse laser-sheet imaging of native in-cylinder structures is also demonstrated, for the purpose of velocimetry.

  8. SU-E-I-20: Comprehensive Quality Assurance Test of Second Generation Toshiba Aquilion Large Bore CT Simulator Based On AAPM TG-66 Recommendations

    SciTech Connect

    Zhang, D

    2015-06-15

    Purpose: AAPM radiation therapy committee task group No. 66 (TG-66) published a report which described a general approach to CT simulator QA. The report outlines the testing procedures and specifications for the evaluation of patient dose, radiation safety, electromechanical components, and image quality for a CT simulator. The purpose of this study is to thoroughly evaluate the performance of a second generation Toshiba Aquilion Large Bore CT simulator with 90 cm bore size (Toshiba, Nasu, JP) based on the TG-66 criteria. The testing procedures and results from this study provide baselines for a routine QA program. Methods: Different measurements and analysis were performed including CTDIvol measurements, alignment and orientation of gantry lasers, orientation of the tabletop with respect to the imaging plane, table movement and indexing accuracy, Scanogram location accuracy, high contrast spatial resolution, low contrast resolution, field uniformity, CT number accuracy, mA linearity and mA reproducibility using a number of different phantoms and measuring devices, such as CTDI phantom, ACR image quality phantom, TG-66 laser QA phantom, pencil ion chamber (Fluke Victoreen) and electrometer (RTI Solidose 400). Results: The CTDI measurements were within 20% of the console displayed values. The alignment and orientation for both gantry laser and tabletop, as well as the table movement and indexing and scanogram location accuracy were within 2mm as specified in TG66. The spatial resolution, low contrast resolution, field uniformity and CT number accuracy were all within ACR’s recommended limits. The mA linearity and reproducibility were both well below the TG66 threshold. Conclusion: The 90 cm bore size second generation Toshiba Aquilion Large Bore CT simulator that comes with 70 cm true FOV can consistently meet various clinical needs. The results demonstrated that this simulator complies with the TG-66 protocol in all aspects including electromechanical component

  9. Conversion of low BMEP 4-cylinder to high BMEP 2-cylinder large bore natural gas engine

    NASA Astrophysics Data System (ADS)

    Ladd, John

    There are more than 6,000 integral compressor engines in use on US natural gas pipelines, operating 24 hours a day, 365 days a year. Many of these engines have operated continuously for more than 50 years, with little to no modifications. Due to recent emission regulations at the local, state and federal levels much of the aging infrastructure requires retrofit technology to remain within compliance. The Engines and Energy Conversion Laboratory was founded to test these retrofit technologies on its large bore engine testbed (LBET). The LBET is a low brake mean effective pressure (BMEP) Cooper Bessemer GMVTF-4. Newer GMV models, constructed in 1980's, utilize turbocharging to increase the output power, achieving BMEP's nearly double that of the LBET. To expand the lab's testing capability and to reduce the LBET's running cost: material testing, in-depth modeling, and on engine testing was completed to evaluate the feasibility of uprating the LBET to a high BMEP two cylinder engine. Due to the LBET's age, the crankcase material properties were not known. Material samples were removed from engine to conduct an in-depth material analysis. It was found that the crankcase was cast out of a specific grade of gray iron, class 25 meehanite. A complete three dimensional model of the LBET's crankcase and power cylinders was created. Using historical engine data, the force inputs were created for a finite element analysis model of the LBET, to determine the regions of high stress. The areas of high stress were instrumented with strain gauges to iterate and validate the model's findings. Several test cases were run at the high and intermediate BMEP engine conditions. The model found, at high BMEP conditions the LBET would operate at the fatigue limit of the class 25 meehanite, operating with no factor of safety but the intermediate case were deemed acceptable.

  10. Design of an RF Antenna for a Large0Bore, High Power, Steady State Plasma Processing Chamber for Material Separation

    SciTech Connect

    Rasmussen, D.A.; Freeman, R.L.

    2001-11-07

    The purpose of this Cooperative Research and Development Agreement (CRADA) between UT-Battelle, LLC, (Contractor), and Archimedes Technology Group, (Participant) is to evaluate the design of an RF antenna for a large-bore, high power, steady state plasma processing chamber for material separation. Criteria for optimization will be to maximize the power deposition in the plasma while operating at acceptable voltages and currents in the antenna structure. The project objectives are to evaluate the design of an RF antenna for a large-bore, high power, steady state plasma processing chamber for material separation. Criteria for optimization will be to maximize the power deposition in the plasma while operating at acceptable voltages and currents in the antenna structure.

  11. 40Ar/39Ar geochronology, paleomagnetism, and evolution of the Boring volcanic field, Oregon and Washington, USA

    USGS Publications Warehouse

    Fleck, Robert J.; Hagstrum, Jonathan T.; Calvert, Andrew T.; Evarts, Russell C.; Conrey, Richard M.

    2014-01-01

    The 40Ar/39Ar investigations of a large suite of fine-grained basaltic rocks of the Boring volcanic field (BVF), Oregon and Washington (USA), yielded two primary results. (1) Using age control from paleomagnetic polarity, stratigraphy, and available plateau ages, 40Ar/39Ar recoil model ages are defined that provide reliable age results in the absence of an age plateau, even in cases of significant Ar redistribution. (2) Grouping of eruptive ages either by period of activity or by composition defines a broadly northward progression of BVF volcanism during latest Pliocene and Pleistocene time that reflects rates consistent with regional plate movements. Based on the frequency distribution of measured ages, periods of greatest volcanic activity within the BVF occurred 2.7–2.2 Ma, 1.7–0.5 Ma, and 350–50 ka. Grouped by eruptive episode, geographic distributions of samples define a series of northeast-southwest–trending strips whose centers migrate from south-southeast to north-northwest at an average rate of 9.3 ± 1.6 mm/yr. Volcanic activity in the western part of the BVF migrated more rapidly than that to the east, causing trends of eruptive episodes to progress in an irregular, clockwise sense. The K2O and CaO values of dated samples exhibit well-defined temporal trends, decreasing and increasing, respectively, with age of eruption. Divided into two groups by K2O, the centers of these two distributions define a northward migration rate similar to that determined from eruptive age groups. This age and compositional migration rate of Boring volcanism is similar to the clockwise rotation rate of the Oregon Coast Range with respect to North America, and might reflect localized extension on the trailing edge of that rotating crustal block.

  12. Arrangement for measuring the field angle of a magnetic field as a function of axial position within a magnet bore tube

    DOEpatents

    Pidcoe, Stephen V.; Zink, Roger A.; Boroski, William N.; McCaw, William R.

    1993-01-01

    An arrangement for measuring the field angle of a magnetic field as a function of axial position within a magnet bore tube of a magnet such as is used with the Superconducting Super Collider (SSC). The arrangement includes a magnetic field alignment gauge that is carried through the magnet bore tube by a positioning shuttle in predetermined increments. The positioning shuttle includes an extensible body assembly which is actuated by an internal piston arrangement. A pair of spaced inflatable cuffs are carried by the body assembly and are selectively actuated in cooperation with pressurizing of the piston to selectively drive the positioning shuttle in an axial direction. Control of the shuttle is provided by programmed electronic computer means located exteriorly of the bore tube and which controls valves provided pressurized fluid to the inflatable cuss and the piston arrangement.

  13. Large-bore tapered-roller bearing performance and endurance to 2.4 million DN

    NASA Technical Reports Server (NTRS)

    Parker, R. J.

    1983-01-01

    The operating characteristics and experimental life estimates for 120.65 mm bore tapered roller bearings of two designs under combined radial and thrust loads were determined. A modified standard bearing design was tested at speeds up to 15,000 rpm. A computer optimized, high speed design was tested at speeds up to 20,000 rpm. Both designs were tested at a combined load of 26,700 N (6000 lb) radial load and and 53,400 N (12,000 lb) thrust load. Advanced helicopter transmissions which require the higher-speed capability of tapered-roller bearings also require higher temperature capability (ref. 2). Thus, materials with temperature capabilities higher than the conventional carburizing steels are required.

  14. Production of electron cyclotron resonance plasma by using multifrequencies microwaves and active beam profile control on a large bore electron cyclotron resonance ion source with permanent magnets.

    PubMed

    Kato, Yushi; Watanabe, Takeyoshi; Matsui, Yuuki; Hirai, Yoshiaki; Kutsumi, Osamu; Sakamoto, Naoki; Sato, Fuminobu; Iida, Toshiyuki

    2010-02-01

    A new concept on magnetic field with all magnets on plasma production and confinement has been proposed to enhance efficiency of an electron cyclotron resonance (ECR) plasma for broad and dense ion beam source under the low pressure. The magnetic field configuration is constructed by a pair of magnets assembly, i.e., comb-shaped magnet which cylindrically surrounds the plasma chamber. The resonance zones corresponding to the fundamental ECR for 2.45 GHz and 11-13 GHz frequencies are constructed at different positions. The profiles of the plasma parameters in the ECR ion source are different from each frequency of microwave. Large bore extractor is set at the opposite side against the microwave feeds. It is found that differences of their profiles also appear at those of ion beam profiles. We conducted to launch simultaneously multiplex frequencies microwaves controlled individually, and tried to control the profiles of the plasma parameters and then those of extracted ion beam.

  15. Multi-Frequency Microwaves Plasma Production for Active Profile Control of Ion Beams on a Large Bore ECR Ion Source with Permanent Magnets

    SciTech Connect

    Sakamoto, Naoki; Kato, Yushi; Kiriyama, Ryutaro; Takenaka, Tomoya; Sato, Fuminobu; Iida, Toshiyuki

    2011-01-07

    A new concept on magnetic field of plasma production and confinement by using permanent magnets, i.e. cylindrically comb-shaped magnets, has been proposed to enhance efficiency of an electron cyclotron resonance (ECR) plasma for broad and dense ion beam source under the low pressure and also the low microwave power. The resonance zones corresponding to the fundamental ECR for 2.45 GHz and 11-13 GHz frequency are constructed at different positions. The profiles of the plasma parameters in the ECR ion source are different from each frequency of microwave. Large bore extractor is set at the opposite side against the microwave feeds. It is found that differences of their profiles also appear at those of ion beam profiles. We conducted to launch simultaneously multiplex frequency microwaves controlled individually, and tried to control the profiles of the plasma parameters and then those of extracted ion beam.

  16. NOx Reduction with Natural Gas for Lean Large-Bore Engine Applications Using Lean NOx Trap Aftertreatment

    SciTech Connect

    Parks, JE

    2005-02-11

    Large-bore natural gas engines are used for distributed energy and gas compression since natural gas fuel offers a convenient and reliable fuel source via the natural gas pipeline and distribution infrastructure. Lean engines enable better fuel efficiency and lower operating costs; however, NOx emissions from lean engines are difficult to control. Technologies that reduce NOx in lean exhaust are desired to enable broader use of efficient lean engines. Lean NOx trap catalysts have demonstrated greater than 90% NOx reduction in lean exhaust from engines operating with gasoline, diesel, and natural gas fuels. In addition to the clean nature of the technology, lean NOx traps reduce NOx with the fuel source of the engine thereby eliminating the requirement for storage and handling of secondary fuels or reducing agents. A study of lean NOx trap catalysts for lean natural gas engines is presented here. Testing was performed on a Cummins C8.3G (CG-280) engine on a motor dynamometer. Lean NOx trap catalysts were tested for NOx reduction performance under various engine operating conditions, and the utilization of natural gas as the reductant fuel source was characterized. Engine test results show that temperature greatly affects the catalytic processes involved, specifically methane oxidation and NOx storage on the lean NOx trap. Additional studies on a bench flow reactor demonstrate the effect of precious metal loading (a primary cost factor) on lean NOx trap performance at different temperatures. Results and issues related to the potential of the lean NOx trap technology for large-bore engine applications will be discussed.

  17. Conditions for tidal bore formation in convergent alluvial estuaries

    NASA Astrophysics Data System (ADS)

    Bonneton, Philippe; Filippini, Andrea Gilberto; Arpaia, Luca; Bonneton, Natalie; Ricchiuto, Mario

    2016-04-01

    Over the last decade there has been an increasing interest in tidal bore dynamics. However most studies have been focused on small-scale bore processes. The present paper describes the first quantitative study, at the estuary scale, of the conditions for tidal bore formation in convergent alluvial estuaries. When freshwater discharge and large-scale spatial variations of the estuary water depth can be neglected, tide propagation in such estuaries is controlled by three main dimensionless parameters: the nonlinearity parameter ε0 , the convergence ratio δ0 and the friction parameter ϕ0. In this paper we explore this dimensionless parameter space, in terms of tidal bore occurrence, from a database of 21 estuaries (8 tidal-bore estuaries and 13 non tidal-bore estuaries). The field data point out that tidal bores occur for convergence ratios close to the critical convergence δc. A new proposed definition of the friction parameter highlights a clear separation on the parameter plane (ϕ0,ε0) between tidal-bore estuaries and non tidal-bore estuaries. More specifically, we have established that tidal bores occur in convergent estuaries when the nonlinearity parameter is greater than a critical value, εc , which is an increasing function of the friction parameter ϕ0. This result has been confirmed by numerical simulations of the two-dimensional Saint Venant equations. The real-estuary observations and the numerical simulations also show that, contrary to what is generally assumed, tide amplification is not a necessary condition for tidal bore formation. The effect of freshwater discharge on tidal bore occurrence has been analyzed from the database acquired during three long-term campaigns carried out on the Gironde/Garonne estuary. We have shown that in the upper estuary the tidal bore intensity is mainly governed by the local dimensionless tide amplitude ε. The bore intensity is an increasing function of ε and this relationship does not depend on freshwater

  18. Observations of large-amplitude cross-shore internal bores near the shelf break, Santa Monica Bay, CA

    USGS Publications Warehouse

    Noble, M.A.; Xu, J. P.

    2003-01-01

    Two sets of moorings were deployed along a cross-shelf transect in central Santa Monica bay for four months in the winter of 1998-1999. Both sites had an array of instruments attached to tripods set on the seafloor to monitor currents over the entire water column, surface waves, near-bed temperature, water clarity and suspended sediment. A companion mooring had temperature sensors spaced approximately 10 m apart to measure temperature profiles between the surface and the seafloor. One array was deployed in 70 m of water at a site adjacent to the shelf break, just northwest of a major ocean outfall. The other was deployed on the mid shelf in 35 m of water approximately 6 km from the shelf break site. The subtidal currents in the region flowed parallel to the isobaths with fluctuating time scales around 10 days, a typical coastal-ocean pattern. However, during the falling phase of the barotropic spring tide, sets of large-amplitude, sheared cross-shore current pulses with a duration of 2-5 h were observed at the shelf break site. Currents in these pulses flowed exclusively offshore in a thin layer near the bed with amplitudes reaching 30-40 cm/s. Simultaneously, currents with amplitudes around 15-20 cm/s flowed exclusively onshore in the thicker layer between the offshore flow layer and the sea surface. The net offshore transport was about half the onshore transport. Near-surface isotherms were depressed 30-40 m. These pulses were likely internal bores generated by tidal currents. Bed stresses associated with these events exceeded 3 dynes/cm2. These amplitudes are large enough to resuspend and transport not only fine-grained material, but also medium to coarse sands from the shelf toward the slope. Consequently, the seafloor over the shelf break was swept clear of fine sediments. The data suggest that the internal bores dissipate and are reduced in amplitude as they propagate across this relatively narrow shelf. There is evidence that they reach the 35 m site, but

  19. Improvement of microwave feeding on a large bore ECRIS with permanent magnets by using coaxial semi-dipole antenna

    SciTech Connect

    Kurisu, Yosuke; Sakamoto, Naoki; Kiriyama, Ryutaro; Takenaka, Tomoya; Nozaki, Dai; Yano, Keisuke; Sato, Fuminobu; Kato, Yushi; Iida, Toshiyuki

    2012-11-06

    We are constructing a tandem type electron cyclotron resonance (ECR) ion source (ECRIS). The first stage of this ECRIS has a large-bore with cylindrically comb-shaped permanent magnets. 2.45GHz and 11-13GHz microwaves can be supplied individually and simultaneously to the plasma chamber. For 2.45GHz, a coaxial semi-dipole antenna is used to feed the microwaves. In previous experiments, there were two problems encountered when running the 2.45GHz microwaves. High incident power was necessary to keep ECR discharge at low operating pressure because of high reflected microwave power. The surface of a support insulator between the inner and the outer electrodes of coaxial semi-dipole antenna was easily metalized by sputtering of the metal wall inside the chamber. The purpose of this study was to solve these problems. Performing several simulation experiments supports the hypothesis that the position of the support insulator is significant for microwave power efficiency. The end result was the ability to sustain ECR discharges at extremely low incident microwave power, several tens of watts, by optimized matching of the position and shape of the insulator.

  20. Surface-Treated versus Untreated Large-Bore Catheters as Vascular Access in Hemodialysis and Apheresis Treatments

    PubMed Central

    Bambauer, Rolf; Schiel, Ralf; Bambauer, Carolin; Latza, Reinhard

    2012-01-01

    Background. Catheter-related infections, thrombosis, and stenosis are among the most frequent complications associated with catheters, which are inserted in vessels. Surface treatment processes of the outer surface, such as ion-beam-assisted deposition, can be used to mitigate such complications. Methods. This retrospective study (1992–2007) evaluated silver-coated (54 patients) and noncoated (105 patients) implanted large-bore catheters used for extracorporeal detoxification. The catheters were inserted into the internal jugular or subclavian veins. After removal, the catheters were cultured for bacterial colonization using standard microbiologic assays. They also were examined using scanning electron microscope. Results. The silver coated catheters showed a tendency towards longer in situ time. The microbiologic examinations of the catheter tips were in both catheter types high positive, but not significant. Conclusion. The silver-coated catheters showed no significantly reduction in infection rate by evaluation of all collected data in this retrospective study. There was no association between both catheters in significantly reducing savings in treatment costs and in reducing patient discomfort. Other new developed catheter materials such as the microdomain-structured inner and outer surface are considered more biocompatible because they mimic the structure of natural biological surface. PMID:22577548

  1. Successive impact of tidal bores on sedimentary processes: Arcins channel, Garonne River

    NASA Astrophysics Data System (ADS)

    Reungoat, David; Leng, Xinqian; Chanson, Hubert

    2017-03-01

    A tidal bore is a hydrodynamic shock, propagating upstream as the tidal flow turns to rising, with macro-tidal conditions in a funnel shaped system with shallow waters. The tidal bore of the Garonne River was extensively investigated in the Arcins channel between 2010 and 2013, typically over one to two days. In 2015, new field measurements were repeated systematically at the same site on 29 August-1 September 2015 and on 27 October 2015. The nature of the observations was comprehensive, encompassing hydrodynamics and turbulence, as well as sediment properties and transport. The tidal bore occurrence had a marked effect on the velocity and suspended sediment field, including a rapid flow deceleration and flow reversal during the bore passage, with very large suspended sediment concentrations (SSCs) during the passage of the tidal bore front and early flood tide, as well as very large suspended sediment flux during the very early flood tide. The suspended sediment concentration (SSC) data indicated a gradual increase in initial mean SSC estimate prior to the bore from 29 August to 1 September 2015. A comparison between suspended sediment flux data showed very significant suspended sediment flux on the first day of tidal bore occurrence, with a decreasing magnitude over the next three days. The data suggested a two-stage bed scour process: at each tidal bore event, surface erosion occurred initially, in the form of stripping; the first stage was followed by delayed mass erosion, occurring about 5-15 min after the tidal bore.

  2. Operating characteristics of a three-piece-inner-ring large-bore roller bearing to speeds of 3 million DN

    NASA Technical Reports Server (NTRS)

    Schuller, F. T.

    1984-01-01

    A 118 mm bore roller bearing with a three piece inner ring ran successfully at 300,000 DN for 20 hr. Provisions were made for lubrication and cooling through the inner ring. In some tests the outer ring was also cooled. Power loss within the bearing increased with both speed and total oil flow rate to the inner ring. Outer ring temperature decreased by as much as 22 K (40 F) when outer ring cooling was employed whereas inner ring temperature remained essentially constant. Cage slip was greatly reduced or even eliminated by using a bearing with a very tight clearance at operating speed. A three piece inner ring bearing had higher inner ring temperatures and less temperature difference between the inner and outer rings than a conventional one piece inner ring bearing.

  3. Inflating with large effective fields

    SciTech Connect

    Burgess, C.P.; Cicoli, M.; Quevedo, F.; Williams, M. E-mail: mcicoli@ictp.it E-mail: mwilliams@perimeterinsititute.ca

    2014-11-01

    We re-examine large scalar fields within effective field theory, in particular focussing on the issues raised by their use in inflationary models (as suggested by BICEP2 to obtain primordial tensor modes). We argue that when the large-field and low-energy regimes coincide the scalar dynamics is most effectively described in terms of an asymptotic large-field expansion whose form can be dictated by approximate symmetries, which also help control the size of quantum corrections. We discuss several possible symmetries that can achieve this, including pseudo-Goldstone inflatons characterized by a coset G/H (based on abelian and non-abelian, compact and non-compact symmetries), as well as symmetries that are intrinsically higher dimensional. Besides the usual trigonometric potentials of Natural Inflation we also find in this way simple large-field power laws (like V ∝ φ{sup 2}) and exponential potentials, V(φ) = ∑{sub k}V{sub x}e{sup −kφ/M}. Both of these can describe the data well and give slow-roll inflation for large fields without the need for a precise balancing of terms in the potential. The exponential potentials achieve large r through the limit |η| || ε and so predict r ≅ (8/3)(1-n{sub s}); consequently n{sub s} ≅ 0.96 gives r ≅ 0.11 but not much larger (and so could be ruled out as measurements on r and n{sub s} improve). We examine the naturalness issues for these models and give simple examples where symmetries protect these forms, using both pseudo-Goldstone inflatons (with non-abelian non-compact shift symmetries following familiar techniques from chiral perturbation theory) and extra-dimensional models.

  4. The Boring Volcanic Field of the Portland-Vancouver area, Oregon and Washington: tectonically anomalous forearc volcanism in an urban setting

    USGS Publications Warehouse

    Evarts, Russell C.; Conrey, Richard M.; Fleck, Robert J.; Hagstrum, Jonathan T.; O'Connor, Jim; Dorsey, Rebecca; Madin, Ian P.

    2009-01-01

    More than 80 small volcanoes are scattered throughout the Portland-Vancouver metropolitan area of northwestern Oregon and southwestern Washington. These volcanoes constitute the Boring Volcanic Field, which is centered in the Neogene Portland Basin and merges to the east with coeval volcanic centers of the High Cascade volcanic arc. Although the character of volcanic activity is typical of many monogenetic volcanic fields, its tectonic setting is not, being located in the forearc of the Cascadia subduction system well trenchward of the volcanic-arc axis. The history and petrology of this anomalous volcanic field have been elucidated by a comprehensive program of geologic mapping, geochemistry, 40Ar/39Ar geochronology, and paleomag-netic studies. Volcanism began at 2.6 Ma with eruption of low-K tholeiite and related lavas in the southern part of the Portland Basin. At 1.6 Ma, following a hiatus of ~0.8 m.y., similar lavas erupted a few kilometers to the north, after which volcanism became widely dispersed, compositionally variable, and more or less continuous, with an average recurrence interval of 15,000 yr. The youngest centers, 50–130 ka, are found in the northern part of the field. Boring centers are generally monogenetic and mafic but a few larger edifices, ranging from basalt to low-SiO2 andesite, were also constructed. Low-K to high-K calc-alkaline compositions similar to those of the nearby volcanic arc dominate the field, but many centers erupted magmas that exhibit little influence of fluids derived from the subducting slab. The timing and compositional characteristics of Boring volcanism suggest a genetic relationship with late Neogene intra-arc rifting.

  5. Enantioselective column coupled electrophoresis employing large bore capillaries hyphenated with tandem mass spectrometry for ultra-trace determination of chiral compounds in complex real samples.

    PubMed

    Piešťanský, Juraj; Maráková, Katarína; Kovaľ, Marián; Havránek, Emil; Mikuš, Peter

    2015-12-01

    A new multidimensional analytical approach for the ultra-trace determination of target chiral compounds in unpretreated complex real samples was developed in this work. The proposed analytical system provided high orthogonality due to on-line combination of three different methods (separation mechanisms), i.e. (1) isotachophoresis (ITP), (2) chiral capillary zone electrophoresis (chiral CZE), and (3) triple quadrupole mass spectrometry (QqQ MS). The ITP step, performed in a large bore capillary (800 μm), was utilized for the effective sample pretreatment (preconcentration and matrix clean-up) in a large injection volume (1-10 μL) enabling to obtain as low as ca. 80 pg/mL limits of detection for the target enantiomers in urine matrices. In the chiral CZE step, the different chiral selectors (neutral, ionizable, and permanently charged cyclodextrins) and buffer systems were tested in terms of enantioselectivity and influence on the MS detection response. The performance parameters of the optimized ITP - chiral CZE-QqQ MS method were evaluated according to the FDA guidance for bioanalytical method validation. Successful validation and application (enantioselective monitoring of renally eliminated pheniramine and its metabolite in human urine) highlighted great potential of this chiral approach in advanced enantioselective biomedical applications.

  6. Water flow measurement in large bore pipes: an experimental comparison between two different types of insertion flowmeters.

    PubMed

    Cascetta, Furio; Palombo, Adolfo; Scalabrini, Gianfranco

    2003-04-01

    In this paper the metrological behavior of two different insertion flowmeters (magnetic and turbine types) in large water pipes is described. A master-slave calibration was carried out in order to estimate the overall uncertainty of the tested meters. The experimental results show that (i) the magnetic insertion tested flowmeter performs the claimed accuracy (+/- 2%) within all the flow range (20:1); (ii) the insertion turbine tested meter, instead, reaches the claimed accuracy just in the upper zone of the flow range.

  7. Double diameter boring tool

    DOEpatents

    Ashbaugh, Fred N.; Murry, Kenneth R.

    1988-12-27

    A boring tool and a method of operation are provided for boring two concentric holes of precision diameters and depths in a single operation. The boring tool includes an elongated tool body, a shank for attachment to a standard adjustable boring head which is used on a manual or numerical control milling machine and first and second diametrically opposed cutting edges formed for cutting in opposite directions. The diameter of the elongated tool body is substantially equal to the distance from the first cutting edge tip to the axis of rotation plus the distance from the second cutting edge tip to the axis of rotation. The axis of rotation of the tool is spaced from the tool centerline a distance substantially equal to one-half the distance from the second cutting edge tip to the axis of rotation minus one-half the distance from the first cutting edge tip to the axis of rotation. The method includes the step of inserting the boring tool into the boring head, adjusting the distance between the tool centerline and the tool axis of rotation as described above and boring the two concentric holes.

  8. Double diameter boring tool

    DOEpatents

    Ashbaugh, F.A.; Murry, K.R.

    1986-02-10

    A boring tool and a method of operation are provided for boring two concentric holes of precision diameters and depths in a single operation. The boring tool includes an elongated tool body, a shank for attachment to a standard adjustable boring head which is used on a manual or numerical control milling machine and first and second diametrically opposed cutting flutes formed for cutting in opposite directions. The diameter of the elongated tool body is substantially equal to the distance from the first flute tip to the axis of rotation plus the distance from the second flute tip to the axis of rotation. The axis of rotation of the tool is spaced from the tool centerline a distance substantially equal to one-half the distance from the second flute tip to the axis of rotation minus one-half the distance from the first flute tip to the axis of rotation. The method includes the step of inserting the boring tool into the boring head, adjusting the distance between the tool centerline and the tool axis of rotation as described above and boring the two concentric holes.

  9. Slime thickness evaluation of bored piles by electrical resistivity probe

    NASA Astrophysics Data System (ADS)

    Chun, Ok-Hyun; Yoon, Hyung-Koo; Park, Min-Chul; Lee, Jong-Sub

    2014-09-01

    The bottoms of bored piles are generally stacked with soil particles, both while boreholes are being drilled, and afterward. The stacked soils are called slime, and when loads are applied on the pile, increase the pile settlement. Thus to guarantee the end bearing capacity of bored piles, the slime thickness should be precisely detected. The objective of this study is to suggest a new method for evaluating the slime thickness, using temperature compensated electrical resistivity. Laboratory studies are performed in advance, to estimate and compare the resolution of the electrical resistivity probe (ERP) and time domain reflectometry (TDR). The electrical properties of the ERP and TDR are measured using coaxial type electrodes and parallel type two-wire electrodes, respectively. Penetration tests, conducted in the fully saturated sand-clay mixtures, demonstrate that the ERP produces a better resolution of layer detection than TDR. Thus, field application tests using the ERP with a diameter of 35.7 mm are conducted for the investigation of slime thickness in large diameter bored piles. Field tests show that the slime layers are clearly identified by the ERP: the electrical resistivity dramatically increases at the interface between the slurry and slime layer. The electrical resistivity in the slurry layer inversely correlates with the amount of circulated water. This study suggests that the new electrical resistivity method may be a useful method for the investigation of the slime thickness in bored piles.

  10. Rotary earth boring tool

    SciTech Connect

    Dismukes, N.B.

    1983-09-27

    The present invention provides a nonstalling system for advancing a boring tool in situations where the inclination of the bore hole with respect to the vertical is such that the force of gravity does not provide effective forward thrust. A hydraulically powered marine screw propeller adjacent the boring tool provides the necessary thrust for the drilling operation. Pressurized drilling fluid provides the required hydraulic energy. The characteristics of the marine screw propeller are such that it provides maximum thrust at maximum rotative speed but should the tool stall the forward thrust drops to zero preventing stalling.

  11. Paleomagnetism and 40Ar/39Ar geochronology of the Plio-Pleistocene Boring Volcanic Field: Implications for the geomagnetic polarity time scale and paleosecular variation

    NASA Astrophysics Data System (ADS)

    Hagstrum, Jonathan T.; Fleck, Robert J.; Evarts, Russell C.; Calvert, Andrew T.

    2017-01-01

    Paleomagnetic directions and 40Ar/39Ar ages have been determined for samples of lava flows from the same outcrops, where possible, for 84 eruptive units ranging in age from 3200 ka to 60 ka within the Boring Volcanic Field (BVF) of the Pacific Northwest, USA. This study expands upon our previous results for the BVF, and compares the combined results with the current geomagnetic polarity time scale (GPTS). Lava flows with transitional directions were found within the BVF at the Matuyama-Brunhes and Jaramillo-Matuyama polarity boundaries, and replicate ages corresponding to these and other boundaries have been newly ascertained. Although the BVF data generally agree with GPTS chronozone boundaries, they indicate that onset of the Gauss-Matuyama transition and Olduvai subchron occurred significantly earlier than given in the current time scale calibration. Additional comparisons show that the BVF results are consistent with recent statistical models of geomagnetic paleosecular variation.

  12. THE DESIGN OF AN RF ANTENNA FOR A LARGE-BORE, HIGH POWER, STEADY STATE PLASMA PROCESSING CHAMBER FOR MATERIAL SEPARATION - CRADA FINAL REPORT for CRADA Number ORNL00-0585

    SciTech Connect

    Rasmussen, D. A.; Freeman, R. L.

    2001-11-07

    The purpose of this Cooperative Research and Development Agreement (CRADA) between UT-Battelle, LLC, (Contractor), and Archimedes Technology Group, (Participant) is to evaluate the design of an RF antenna for a large-bore, high power, steady state plasma processing chamber for material separation. Criteria for optimization will be to maximize the power deposition in the plasma while operating at acceptable voltages and currents in the antenna structure. The project objectives are to evaluate the design of an RF antenna for a large-bore, high power, steady state plasma processing chamber for material separation. Criteria for optimization will be to maximize the power deposition in the plasma while operating at acceptable voltages and currents in the antenna structure.

  13. Paleomagnetism and 40ar/39ar Geochronology of the Plio-Pleistocene Boring Volcanic Field: Implications for the Geomagnetic Polarity Time Scale

    NASA Astrophysics Data System (ADS)

    Hagstrum, J. T.; Fleck, R. J.; Evarts, R. C.; Calvert, A. T.; Conrey, R. M.

    2014-12-01

    The Boring volcanic field (BVF) in western Oregon and Washington has been the subject of a recently completed investigation that included detailed geologic mapping, petrographic and geochemical analyses, and 40Ar/39Ar geochronologic and paleomagnetic studies. At least 80 monogenetic volcanic centers compose the BVF, each of which erupted small volumes of magma ranging from basalt to mafic andesite over short intervals of time. More than 140 40Ar/39Ar determinations for lava flows and intrusions in the BVF range in age from ~3100 ka to ~60 ka. Oriented samples for paleomagnetic analysis were collected at an equivalent number of localities (>160) coincident with, or within the same unit proximal to, the geochronologic sampling sites. Based on the frequency distribution of ages, the most significant episodes of Boring volcanism occurred between 2700 and 2200 ka, 1700 and 500 ka, and 350 and 60 ka. A systematic determination of the BVF's eruptive history was undertaken mainly to assess its anomalous neotectonic setting west of the Cascade arc axis, as well as the magnitude of its concomitant volcanic hazards within the greater Portland and Vancouver metropolitan areas. Our paleomagnetic and geochronologic data, however, also have significant implications for the timing of geomagnetic field reversals and excursions during the Late Pliocene and Pleistocene epochs. The BVF data are more numerous higher in the section, and they capture transitional fields at two polarity boundaries allowing precise age determinations to be made for these reversals: the Brunhes-Matuyama transition is thus dated at 773±5 ka, and the upper Jaramillo-Matuyama transition at 973±6 ka. The lower Jaramillo-Matuyama transition occurred prior to 1068±8 ka, and the normal Cobb subchron must have occurred between reversed-polarity Matuyama flows dated at 1159±14 ka and 1207±6 ka. The lower Olduvai-Matuyama transition occurred prior to 1927±4 ka, and the Matuyama-Gauss transition prior to 2616

  14. Tunnel boring machine

    SciTech Connect

    Snyder, L. L.

    1985-07-09

    A tunnel boring machine for controlled boring of a curvilinear tunnel including a rotating cutter wheel mounted on the forward end of a thrust cylinder assembly having a central longitudinal axis aligned with the cutter wheel axis of rotation; the thrust cylinder assembly comprising a cylinder barrel and an extendable and retractable thrust arm received therein. An anchoring assembly is pivotally attached to the rear end of the cylinder barrel for anchoring the machine during a cutting stroke and providing a rear end pivot axis during curved cutting strokes. A pair of laterally extending, extendable and retractable arms are fixedly mounted at a forward portion of the cylinder barrel for providing lateral displacement in a laterally curved cutting mode and for anchoring the machine between cutting strokes and during straight line boring. Forward and rear transverse displacement and support assemblies are provided to facilitate cutting in a transversely curved cutting mode and to facilitate machine movement between cutting strokes.

  15. Tidal Bore detection in the Garonne River using high frequency GNSS data

    NASA Astrophysics Data System (ADS)

    Frappart, Frédéric; Roussel, Nicolas; Darrozes, José; Bonneton, Philippe; Bonneton, Natalie; Detandt, Guillaume; Perosanz, Felix; Loyer, Sylvain

    2016-04-01

    A tidal bore is a positive surge propagating upstream that may form when a rising tide with significant amplitude enters shallow, gently sloping and narrowing rivers. Tidal bores have a significant impact on the river ecosystem behavior, especially in terms of sediment transport. Most of the existing field studies were limited to visual observations. Only a few field experiments have been devoted to a quantitative study of the tidal bore dynamics. We carried out a field study in August, 2015, using a GNSS buoy to measure the tidal bore in the Garonne River (France) at Podensac located 140 km upstream of the estuary mouth. Precise Point Positioning and Differential GNSS techniques were used to determine the river surface height variations with a 20 Hz sampling rate. This site was selected owing to the presence of well-developed undular tidal bores and also because of the absence of any significant curvature of the river at this location, which limits the complexity of the tidal bore structure. The Gironde estuary is located in the Bay of Biscay, on the southwest coast of France, and is formed from the meeting of the rivers Dordogne and Garonne. In the Gironde mouth, the mean neap tidal range and mean spring tidal range is 2.5 m and 5 m, respectively. As the tide propagates upstream a marked ebbflood asymmetry occurs in the upper reaches of the estuary and the wave is amplified. This large amplitude tidal wave propagates in the Garonne and Dordogne rivers up to 160 km from the estuary mouth. Both GNSS buoy and reference station use a Leica AR10 antenna and GR25 receiver. Both stations (reference and buoy) acquired data with a 20 Hz sampling rate. GNSS data were processed using RTKLib. Results allowed to detect the the wave train of the tidal bore that caused an elevation of the surface of around 1.5 m. Comparisons were performed using acoustic data showing a good agreement between both sources of data.

  16. Low-cost boring mill

    NASA Technical Reports Server (NTRS)

    Hibdon, R. A.

    1979-01-01

    Portable unit and special fixture serve as boring mill. Machine, fabricated primarily from scrap metal, was designed and set up in about 12 working days. It has reduced setup and boring time by 66 percent as compared with existing boring miles, thereby making latter available for other jobs. Unit can be operated by one man.

  17. Testing Large Structures in the Field

    NASA Technical Reports Server (NTRS)

    James, George; Carne, Thomas G.

    2009-01-01

    Field testing large structures creates unique challenges such as limited choices for boundary conditions and the fact that natural excitation sources cannot be removed. Several critical developments in field testing of large structures are reviewed, including: step relaxation testing which has been developed into a useful technique to apply large forces to operational systems by careful windowing; the capability of large structures testing with free support conditions which has been expanded by implementing modeling of the support structure; natural excitation which has been developed as a viable approach to field testing; and the hybrid approach which has been developed to allow forces to be estimated in operating structures. These developments have increased the ability to extract information from large structures and are highlighted in this presentation.

  18. Through bore subsea christmas trees

    SciTech Connect

    Huber, D.S.; Simmers, G.F.C.; Johnson, C.S.

    1985-01-01

    The workovers of subsea completed wells are expensive and time consuming as even the most routine tasks must be carried out by a semi-submersible. This paper describes the economic, safety and operational advantages which led to the development and successful first installation of 'through bore' subsea production trees. The conventional wet subsea trees have proved to be very reliable over the past ten years of operation in the Argyll, Duncan and Innes fields, however the completion strings require pulling on the average about once every three to five years. The conventional subsea tree/tubing hanger set up design requires the tree to be tripped and a rig BOP stack run to pull the tubing. This operation is time consuming, very weather sensitive and leaves the well temporarily without a well control stack on the wellhead. The 7 1/16'' 'through bore' subsea tree was developed to minimize the tubing pulling workover time and several trees have been run successfully since the latter part of 1984. The time saving on a tubing pulling workover is three days. In addition, the design considerably reduces the hazards and equipment damage risk inherent in the conventional design. Hamilton Brothers and National Supply Company in Aberdeen designed the equipment which must be considered a new generation of subsea production trees.

  19. Gravitational waves and large field inflation

    NASA Astrophysics Data System (ADS)

    Linde, Andrei

    2017-02-01

    According to the famous Lyth bound, one can confirm large field inflation by finding tensor modes with sufficiently large tensor-to-scalar ratio r. Here we will try to answer two related questions: is it possible to rule out all large field inflationary models by not finding tensor modes with r above some critical value, and what can we say about the scale of inflation by measuring r? However, in order to answer these questions one should distinguish between two different definitions of the large field inflation and three different definitions of the scale of inflation. We will examine these issues using the theory of cosmological α-attractors as a convenient testing ground.

  20. Operating characteristics of a large-bore roller bearing to speeds of 3 times 10 to the 6th power DN

    NASA Technical Reports Server (NTRS)

    Schuller, F. T.

    1979-01-01

    A 118-millimeter-bore roller bearing was studied parametrically at speeds from 10,000 to 25,500 rpm. The bearing had a round outer ring (not preloaded), and provisions were made for lubrication and cooling through the inner ring. In some tests the outer ring was also cooled. The bearing ran successfully at 300,00 DN with very small evidence of cage slip. Load, which was varied from 2200 to 8900 newtons (500 to 2000 lb), had no effect on bearing temperature or cage slip over the speed range tested. Bearing temperature varied inversely with cage slip for all test conditions. Cooling the outer ring decreased its temperature but increased the inner-ring temperature. Heat rejected to the lubricant (power loss within the bearing) increased with both shaft speed and total oil flow rate to the inner ring.

  1. Bore hole navigator

    SciTech Connect

    Hoffman, G.J.

    1987-09-29

    A bore hole navigator is described comprising a two axis platform for lowering down a bore hole on a cable with its longitudinal axis parallel to the local bore hole direction. The two axis platform has an outer gimbal, bearing supported on the outer gimbal axis for rotation about the longitudinal axis of the platform, and an inner gimbal axis orthogonal the the outer gimbal axis. The inner gimbal axis has multiple axis segments spaced along the longitudinal axis of the platform and each bearing supported on the outer gimbal. The inner gimbal axis segment has a two axis gyro mounted thereon with its spin axis orthogonal to the respective inner gimbal axis segment, a first gyro sensitive axis parallel to the respective inner gimbal axis segment and a second gyro sensitive axis orthogonal to the spin axis. The second inner gimbal axis segment has a pitch torquer thereon operative to provide a controllable torque about the respective inner gimbal axis segment. The third inner gimbal axis segment has a pitch resolver thereon operative to measure rotation of the respective inner gimbal axis segment with respect to the outer gimbal. The first, second and third inner gimbal axis segments are coupled to rotate together. The outer gimbal has a yaw torquer thereon to provide a controllable torque about the outer gimbal axis, and a yaw resolver thereon to measure rotation of the outer gimbal about the outer gimbal axis. The outer gimbal also has a single axis accelerometer therein having its sensitive axis orthogonal to the outer gimbal axis and the inner gimbal axis segments.

  2. Maneuvering impact boring head

    DOEpatents

    Zollinger, W.T.; Reutzel, E.W.

    1998-08-18

    An impact boring head may comprise a main body having an internal cavity with a front end and a rear end. A striker having a head end and a tail end is slidably mounted in the internal cavity of the main body so that the striker can be reciprocated between a forward position and an aft position in response to hydraulic pressure. A compressible gas contained in the internal cavity between the head end of the striker and the front end of the internal cavity returns the striker to the aft position upon removal of the hydraulic pressure. 8 figs.

  3. Maneuvering impact boring head

    DOEpatents

    Zollinger, W. Thor; Reutzel, Edward W.

    1998-01-01

    An impact boring head may comprise a main body having an internal cavity with a front end and a rear end. A striker having a head end and a tail end is slidably mounted in the internal cavity of the main body so that the striker can be reciprocated between a forward position and an aft position in response to hydraulic pressure. A compressible gas contained in the internal cavity between the head end of the striker and the front end of the internal cavity returns the striker to the aft position upon removal of the hydraulic pressure.

  4. Transient electromagnetic fields near large earthing systems

    SciTech Connect

    Grcev, L.D.; Menter, F.E.

    1996-05-01

    Electromagnetic compatibility studies require knowledge of transient voltages that may be developed near earthing systems during lightning discharge, since such voltages may be coupled to sensitive electronic circuits. For such purpose accurate evaluation of transient electric field near to and/or at the surface of the grounding conductors is necessary. In this paper, a procedure for computation of transient fields near large earthing systems, as a response to a typical lightning current impulse, based on computational methodology developed in the field of antennas, is presented. Computed results are favorably compared with published measurement results. The model is applied to check the common assumption that the soil ionization can be neglected in case of large earthing systems. Presented results show that the soil ionization threshold is met and exceeded during typical lightning discharge in a large earthing system.

  5. Large optical field enhancement for nanotips with large opening angles

    NASA Astrophysics Data System (ADS)

    Thomas, Sebastian; Wachter, Georg; Lemell, Christoph; Burgdörfer, Joachim; Hommelhoff, Peter

    2015-06-01

    We theoretically investigate the dependence of the enhancement of optical near-fields at nanometric tips on the shape, size, and material of the tip. We confirm the strong dependence of the field enhancement factor on the radius of curvature. In addition, we find a surprisingly strong increase of field enhancement with increasing opening angle of the nanotips. For gold and tungsten nanotips in the experimentally relevant parameter range (radius of curvature ≥slant 5 nm at 800 nm laser wavelength), we obtain field enhancement factors of up to ∼ 35 for Au and ∼ 12 for W for large opening angles. We confirm this strong dependence on the opening angle for many other materials featuring a wide variety in their dielectric response. For dielectrics, the opening angle dependence is traced back to the electrostatic force of the induced surface charge at the tip shank. For metals, the plasmonic response strongly increases the field enhancement and shifts the maximum field enhancement to smaller opening angles.

  6. Large field inflation from D-branes

    NASA Astrophysics Data System (ADS)

    Escobar, Dagoberto; Landete, Aitor; Marchesano, Fernando; Regalado, Diego

    2016-04-01

    We propose new large field inflation scenarios built on the framework of F-term axion monodromy. Our setup is based on string compactifications where D-branes create potentials for closed string axions via F-terms. Because the source of the axion potential is different from the standard sources of moduli stabilization, it is possible to lower the inflaton mass as compared to other massive scalars. We discuss a particular class of models based on type IIA flux compactifications with D6-branes. In the small field regime they describe supergravity models of quadratic chaotic inflation with a stabilizer field. In the large field regime the inflaton potential displays a flattening effect due to Planck suppressed corrections, allowing us to easily fit the cosmological parameters of the model within current experimental bounds.

  7. Earth boring machine

    SciTech Connect

    Durham, M. E.

    1985-11-19

    An earth boring machine for boring straight and level elongated holes through rock-laden earth. The machine includes a stationary elongated frame upon which a first slide is carried. A second slide is carried on the first slide. An elongated auger guiding sleeve is carried adjacent one end of the first slide and has a cutting edge on a remote end thereof. A power-driven auger assembly is carried on the second slide and includes an auger which extends within the guiding sleeve. A cutting tool is carried on the end of the auger adjacent a remote end of the guiding sleeve. An hydraulic cylinder is provided for advancing the first sleeve for driving the cutting edge of the guiding sleeve into the earth while the power driven auger removes the earth as the guiding sleeve is advanced. Another set of hydraulic cylinders are provided for advancing the second slide on the first slide causing the cutting tool to extend out beyond the remote end of the guiding sleeve for cutting through obstructions in the earth when the cutting edge of the guiding sleeve is prevented from moving forward.

  8. Nonthermal gravitino production after large field inflation

    NASA Astrophysics Data System (ADS)

    Ema, Yohei; Mukaida, Kyohei; Nakayama, Kazunori; Terada, Takahiro

    2016-11-01

    We revisit the nonthermal gravitino production at the (p)reheating stage after inflation. Particular attention is paid to large field inflation models with a ℤ 2 symmetry, for which the previous perturbative analysis is inapplicable; and inflation models with a stabilizer superfield, which have not been studied non-perturbatively. It is found that in single-superfield inflation models (without the stabilizer field), nonthermal production of the transverse gravitino can be cosmologically problematic while the abundance of the lon-gitudinal gravitino is small enough. In multi-superfield inflation models (with the stabilizer field), production of the transverse and longitudinal gravitinos is significantly suppressed, and they are cosmologically harmless. We also clarify the relation between the background field method used in the preheating context and the standard perturbative decay method to estimate the gravitino abundance.

  9. Guided earth boring tool

    SciTech Connect

    McDonald, W.J.; Pittard, G.T.; Maurer, W.C.; Wasson, M.R.; Herben, W.C.

    1989-08-22

    This patent describes a controllable tool for drilling holes in soft earth. The tool comprising an elongated rigid supporting drill rod or pipe, means supporting the drill rod or pipe for earth boring or piercing movement, including means for moving the drill rod or pipe longitudinally for penetrating the earth, means for rotating the drill rod or pipe while penetrating the earth, and means for controlling the direction of movement of the drill rod or pipe along a straight or curved path. The drill rod or pipe moving and rotating means being constructed to permit addition and removal of supporting drill rod or pipe during earth penetrating operation, an earth piercing member of substantially cylindrical shape. The tool being operable to penetrate the earth upon longitudinal movement of the drill rod or pipe by the longitudinal rod or pipe moving means, and the direction controlling means comprising means causing drill rod or pipe movement in a curved path through the earth when the rod or pipe is not rotated and causing drill rod or pipe straight line movement when the rod or pipe is rotated.

  10. Large deviations for nonlocal stochastic neural fields.

    PubMed

    Kuehn, Christian; Riedler, Martin G

    2014-04-17

    We study the effect of additive noise on integro-differential neural field equations. In particular, we analyze an Amari-type model driven by a Q-Wiener process, and focus on noise-induced transitions and escape. We argue that proving a sharp Kramers' law for neural fields poses substantial difficulties, but that one may transfer techniques from stochastic partial differential equations to establish a large deviation principle (LDP). Then we demonstrate that an efficient finite-dimensional approximation of the stochastic neural field equation can be achieved using a Galerkin method and that the resulting finite-dimensional rate function for the LDP can have a multiscale structure in certain cases. These results form the starting point for an efficient practical computation of the LDP. Our approach also provides the technical basis for further rigorous study of noise-induced transitions in neural fields based on Galerkin approximations.Mathematics Subject Classification (2000): 60F10, 60H15, 65M60, 92C20.

  11. Large Deviations for Nonlocal Stochastic Neural Fields

    PubMed Central

    2014-01-01

    We study the effect of additive noise on integro-differential neural field equations. In particular, we analyze an Amari-type model driven by a Q-Wiener process, and focus on noise-induced transitions and escape. We argue that proving a sharp Kramers’ law for neural fields poses substantial difficulties, but that one may transfer techniques from stochastic partial differential equations to establish a large deviation principle (LDP). Then we demonstrate that an efficient finite-dimensional approximation of the stochastic neural field equation can be achieved using a Galerkin method and that the resulting finite-dimensional rate function for the LDP can have a multiscale structure in certain cases. These results form the starting point for an efficient practical computation of the LDP. Our approach also provides the technical basis for further rigorous study of noise-induced transitions in neural fields based on Galerkin approximations. Mathematics Subject Classification (2000): 60F10, 60H15, 65M60, 92C20. PMID:24742297

  12. Seismic Analysis of Tunnel Boring Machine Signals at Kerckhoff Tunnel

    DTIC Science & Technology

    1983-08-01

    of the MSHA system to detect a large tunnel boring machine (TBM) operating in granite at depths in excess of 1300 ft, the degree of accuracy of the...determined that the TBM could be detected at a horizontal range of about 80000 ft and the tunnel boring machine could be accurately located within approximately 100 ft at a slant range of approximately 5000 ft.

  13. Profiles of ion beams and plasma parameters on a multi-frequencies microwaves large bore electron cyclotron resonance ion source with permanent magnets.

    PubMed

    Kato, Yushi; Sakamoto, Naoki; Kiriyama, Ryutaro; Takenaka, Tomoya; Kurisu, Yosuke; Nozaki, Dai; Sato, Fuminobu; Iida, Toshiyuki

    2012-02-01

    In order to contribute to various applications of plasma and beams based on an electron cyclotron resonance, a new concept on magnetic field with all magnets on plasma production and confinement has been proposed with enhanced efficiency for broad and dense ion beam. The magnetic field configuration consists of a pair of comb-shaped magnet surrounding plasma chamber cylindrically. Resonance zones corresponding for 2.45 GHz and 11-13 GHz frequencies are positioned at spatially different positions. We launch simultaneously multiplex frequencies microwaves operated individually, try to control profiles of the plasma parameters and the extracted ion beams, and to measure them in detail.

  14. Profiles of ion beams and plasma parameters on a multi-frequencies microwaves large bore electron cyclotron resonance ion source with permanent magnets

    SciTech Connect

    Kato, Yushi; Sakamoto, Naoki; Kiriyama, Ryutaro; Takenaka, Tomoya; Kurisu, Yosuke; Nozaki, Dai; Sato, Fuminobu; Iida, Toshiyuki

    2012-02-15

    In order to contribute to various applications of plasma and beams based on an electron cyclotron resonance, a new concept on magnetic field with all magnets on plasma production and confinement has been proposed with enhanced efficiency for broad and dense ion beam. The magnetic field configuration consists of a pair of comb-shaped magnet surrounding plasma chamber cylindrically. Resonance zones corresponding for 2.45 GHz and 11-13 GHz frequencies are positioned at spatially different positions. We launch simultaneously multiplex frequencies microwaves operated individually, try to control profiles of the plasma parameters and the extracted ion beams, and to measure them in detail.

  15. Measurement of Antenna Bore-Sight Gain

    NASA Technical Reports Server (NTRS)

    Fortinberry, Jarrod; Shumpert, Thomas H.

    2016-01-01

    The absolute or free-field gain of a simple antenna can be approximated using standard antenna theory formulae or for a more accurate prediction, numerical methods may be employed to solve for antenna parameters including gain. Both of these methods will result in relatively reasonable estimates but in practice antenna gain is usually verified and documented via measurements and calibration. In this paper, a relatively simple and low-cost, yet effective means of determining the bore-sight free-field gain of a VHF/UHF antenna is proposed by using the Brewster angle relationship.

  16. Thrust generator for boring tools

    SciTech Connect

    Dismukes, N.B.

    1984-03-13

    The present invention provides an electrically powered system for advancing a rotary boring tool in situations where the inclination of the bore hole is such that the force of gravity does not provide sufficient forward thrust. One or more marine screw propellers are rotated by the motor which itself is restrained from rotation by being fixedly connected to a flexible, twist resistant conduit for conducting the drilling fluid and electric power from the surface. The system may also provide for different rotative speeds for propeller and bit and for counter-rotating propellers to minimize torque forces on the conduit.

  17. Tsunami Bores in Kitakami River

    NASA Astrophysics Data System (ADS)

    Tolkova, Elena; Tanaka, Hitoshi

    2016-12-01

    The 2011 Tohoku tsunami entered the Kitakami river and propagated there as a train of shock waves, recorded with a 1-min interval at water level stations at Fukuchi, Iino, and the weir 17.2 km from the mouth, where the bulk of the wave was reflected back. The records showed that each bore kept its shape and identity as it traveled a 10.9-km-path Fukuchi-Iino-weir-Iino. Shock handling based on the cross-river integrated classical shock conditions was applied to reconstruct the flow velocity time histories at the measurement sites, to estimate inflow into the river at each site, to evaluate the wave heights of incident and reflected tsunami bores near the weir, and to estimate propagation speed of the individual bores. Theoretical predictions are verified against the measurements. We discuss experiences of exercising the shock conditions with actual tsunami measurements in the Kitakami river, and test applicability of the shallow-water approximation for describing tsunami bores with heights ranging from 0.3 to 4 m in a river segment with a depth of 3-4 m.

  18. Customer Overview of Pulsed Laser Heating for Evaluation of Gun Bore Materials

    DTIC Science & Technology

    2015-05-01

    Technical Report ARWSB-TR-15003 Customer Overview of Pulsed Laser Heating for Evaluation of Gun Bore Materials Mark E. Todaro...SUBTITLE Customer Overview of Pulsed Laser Heating for Evaluation of Gun Bore Materials 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c...thermomechanical effects that occur at the bore of large and medium caliber guns during firing. Hence, PLH has been used not only to gain insight into the erosion

  19. Field-aligned currents and large scale magnetospheric electric fields

    NASA Technical Reports Server (NTRS)

    Dangelo, N.

    1980-01-01

    D'Angelo's model of polar cap electric fields (1977) was used to visualize how high-latitude field-aligned currents are driven by the solar wind generator. The region 1 and region 2 currents of Iijima and Potemra (1976) and the cusp field-aligned currents of Wilhjelm et al. (1978) and McDiarmid et al. (1978) are apparently driven by different generators, although in both cases the solar wind is their ultimate source.

  20. Fast magnetic reconnection with large guide fields

    DOE PAGES

    Stanier, A.; Simakov, Andrei N.; Chacón, L.; ...

    2015-01-09

    We domonstrate, using two-fluid simulations, that low-βmagnetic reconnection remains fast, regardless of the presence of fast dispersive waves, which have been previously suggested to play a critical role. In order to understand these results, a discrete model is constructed that offers scaling relationships for the reconnection rate and dissipation region (DR) thickness in terms of the upstream magnetic field and DR length. Moreover, we verify these scalings numerically and show how the DR self-adjusts to process magnetic flux at the same rate that it is supplied to a larger region where two-fluid effects become important. The rate is therefore independentmore » of the DR physics and is in good agreement with kinetic results.« less

  1. Size segregation in a granular bore

    NASA Astrophysics Data System (ADS)

    Edwards, A. N.; Vriend, N. M.

    2016-10-01

    We investigate the effect of particle-size segregation in an upslope propagating granular bore. A bidisperse mixture of particles, initially normally graded, flows down an inclined chute and impacts with a closed end. This impact causes the formation of a shock in flow thickness, known as a granular bore, to travel upslope, leaving behind a thick deposit. This deposit imprints the local segregated state featuring both pure and mixed regions of particles as a function of downstream position. The particle-size distribution through the depth is characterized by a thin purely small-particle layer at the base, a significant linear transition region, and a thick constant mixed-particle layer below the surface, in contrast to previously observed S-shaped steady-state concentration profiles. The experimental observations agree with recent progress that upward and downward segregation of large and small particles respectively is asymmetric. We incorporate the three-layer, experimentally observed, size-distribution profile into a depth-averaged segregation model to modify it accordingly. Numerical solutions of this model are able to match our experimental results and therefore motivate the use of a more general particle-size distribution profile.

  2. Site study plan for Exploratory shaft facilities design foundation boreholes (shaft surface facility foundation borings), Deaf Smith County Site, Texas: Surface-based geotechnical field program: Preliminary draft

    SciTech Connect

    Not Available

    1987-12-01

    This site study plan describes the Exploratory Shaft Facilities (ESF) Design Foundation Boreholes field activities to be conducted during early stages of Site Characterization at the Deaf Smith County, Texas, site. The field program has been designed to provide data useful in addressing information/data needs resulting from federal/state/local regulations, and repository program requirements. Approximately 50 foundation boreholes will be drilled within the ESP location to provide data necessary for design of the ESF and to satisfy applicable shaft permitting requirements. Soils and subsurface rock will be sampled as the foundation boreholes are advanced. Soil samples or rock core will be taken through the Blackwater Draw and Ogallala Formations and the Dockum Group. Hydrologic testing will be performed in boreholes that penetrates the water table. In-situ elastic properties will be determined from both the soil strata and rock units along the length of the boreholes. Field methods/tests are chosen that provide the best or only means of obtaining the required data. The Salt Repository Project (SRP) Networks specify the schedule under which the program will operate. Drilling will not begin until after site ground water baseline conditions have been established. The Technical Field Services Contractor is responsible for conducting the field program of drilling and testing. Samples and data will be handled and reported in accordance with established SRP procedures. A quality assurance program will be utilized to assure that activities affecting quality are performed correctly and that the appropriate documentation is maintained. 25 refs., 10 figs., 6 tabs.

  3. PERMANENT MAGNET DESIGNS WITH LARGE VARIATIONS IN FIELD STRENGTH.

    SciTech Connect

    GUPTA,R.

    2004-01-21

    The use of permanent magnets has been investigated as an option for electron cooling ring for the proposed luminosity upgrade of RHIC. Several methods have been developed that allow a large variation in field strength. These design concepts were verified with computer simulations using finite element codes. It will be shown that the field uniformity is maintained while the field strength is mechanically adjusted.

  4. Cam-controlled boring bar

    DOEpatents

    Glatthorn, Raymond H.

    1986-01-01

    A cam-controlled boring bar system (100) includes a first housing (152) which is rotatable about its longitudinal axis (154), and a second housing in the form of a cam-controlled slide (158) which is also rotatable about the axis (154) as well as being translatable therealong. A tool-holder (180) is mounted within the slide (158) for holding a single point cutting tool. Slide (158) has a rectangular configuration and is disposed within a rectangularly configured portion of the first housing (152). Arcuate cam slots (192) are defined within a side plate (172) of the housing (152), while cam followers (194) are mounted upon the cam slide (158) for cooperative engagement with the cam slots (192). In this manner, as the housing (152) and slide (158) rotate, and as the slide (158) also translates, a through-bore (14) having an hourglass configuration will be formed within a workpiece (16) which may be, for example, a nuclear reactor steam generator tube support plate.

  5. Large Field, High Resolution Full-Field Optical Coherence Tomography

    PubMed Central

    Assayag, Osnath; Antoine, Martine; Sigal-Zafrani, Brigitte; Riben, Michael; Harms, Fabrice; Burcheri, Adriano; Grieve, Kate; Dalimier, Eugénie; Le Conte de Poly, Bertrand; Boccara, Claude

    2014-01-01

    We present a benchmark pilot study in which high-resolution Full-Field Optical Coherence Tomography (FF-OCT) was used to image human breast tissue and is evaluated to assess its ability to aid the pathologist’s management of intra-operative diagnoses. FF-OCT imaging safety was investigated and agreement between FF-OCT and routinely prepared histopathological images was evaluated. The compact setup used for this study provides 1 µm3 resolution and 200 µm imaging depth, and a 2.25 cm2 specimen is scanned in about 7 minutes. 75 breast specimens were imaged from 22 patients (21 women, 1 man) with a mean age of 58 (range: 25-83). Pathologists blind diagnosed normal/benign or malignant tissue based on FF-OCT images alone, diagnosis from histopathology followed for comparison. The contrast in the FF-OCT images is generated by intrinsic tissue scattering properties, meaning that no tissue staining or preparation is required. Major architectural features and tissue structures of benign breast tissue, including adipocytes, fibrous stroma, lobules and ducts were characterized. Subsequently, features resulting from pathological modification were characterized and a diagnosis decision tree was developed. Using FF-OCT images, two breast pathologists were able to distinguish normal/benign tissue from lesional with a sensitivity of 94% and 90%, and specificity of 75% and 79% respectively. PMID:24000981

  6. High performance projectile seal development for non perfect railgun bores

    SciTech Connect

    Wolfe, T.R.; Vine, F.E. Le; Riedy, P.E.; Panlasigui, A.; Hawke, R.S.; Susoeff, A.R.

    1997-01-01

    The sealing of high pressure gas behind an accelerating projectile has been developed over centuries of use in conventional guns and cannons. The principal concern was propulsion efficiency and trajectory accuracy and repeatability. The development of guns for use as high pressure equation-of-state (EOS) research tools, increased the importance of better seals to prevent gas leakage from interfering with the experimental targets. The development of plasma driven railguns has further increased the need for higher quality seals to prevent gas and plasma blow-by. This paper summarizes more than a decade of effort to meet these increased requirements. In small bore railguns, the first improvement was prompted by the need to contain the propulsive plasma behind the projectile to avoid the initiation of current conducting paths in front of the projectile. The second major requirements arose from the development of a railgun to serve as an EOS tool where it was necessary to maintain an evacuated region in front of the projectile throughout the acceleration process. More recently, the techniques developed for the small bore guns have been applied to large bore railguns and electro-thermal chemical guns in order to maximize their propulsion efficiency. Furthermore, large bore railguns are often less rigid and less straight than conventional homogeneous material guns. Hence, techniques to maintain seals in non perfect, non homogeneous material launchers have been developed and are included in this paper.

  7. Boring crustaceans damage polystyrene floats under docks polluting marine waters with microplastic.

    PubMed

    Davidson, Timothy M

    2012-09-01

    Boring isopods damage expanded polystyrene floats under docks and, in the process, expel copious numbers of microplastic particles. This paper describes the impacts of boring isopods in aquaculture facilities and docks, quantifies and discusses the implications of these microplastics, and tests if an alternate foam type prevents boring. Floats from aquaculture facilities and docks were heavily damaged by thousands of isopods and their burrows. Multiple sites in Asia, Australia, Panama, and the USA exhibited evidence of isopod damage. One isopod creates thousands of microplastic particles when excavating a burrow; colonies can expel millions of particles. Microplastics similar in size to these particles may facilitate the spread of non-native species or be ingested by organisms causing physical or toxicological harm. Extruded polystyrene inhibited boring, suggesting this foam may prevent damage in the field. These results reveal boring isopods cause widespread damage to docks and are a novel source of microplastic pollution.

  8. Connecting wind-driven upwelling and offshore stratification to nearshore internal bores and oxygen variability

    NASA Astrophysics Data System (ADS)

    Walter, Ryan K.; Woodson, C. Brock; Leary, Paul R.; Monismith, Stephen G.

    2014-06-01

    This study utilizes field observations in southern Monterey Bay, CA, to examine how regional-scale upwelling and changing offshore (shelf) conditions influence nearshore internal bores. We show that the low-frequency wind forcing (e.g., upwelling/relaxation time scales) modifies the offshore stratification and thermocline depth. This in turn alters the strength and structure of observed internal bores in the nearshore. An internal bore strength index is defined using the high-pass filtered potential energy density anomaly in the nearshore. During weak upwelling favorable conditions and wind relaxations, the offshore thermocline deepens. In this case, both the amplitude of the offshore internal tide and the strength of the nearshore internal bores increase. In contrast, during strong upwelling conditions, the offshore thermocline shoals toward the surface, resulting in a decrease in the offshore internal tide amplitude. As a result, cold water accumulates in the nearshore (nearshore pooling), and the internal bore strength index decreases. Empirical orthogonal functions are utilized to support the claim that the bore events contribute to the majority of the variance in cross-shelf exchange and transport in the nearshore. Observed individual bores can drive shock-like drops in dissolved oxygen (DO) with rapid onset times, while extended upwelling periods with reduced bore activity produce longer duration, low DO events.

  9. Quality Designed Twin Wire Arc Spraying of Aluminum Bores

    NASA Astrophysics Data System (ADS)

    König, Johannes; Lahres, Michael; Methner, Oliver

    2015-01-01

    After 125 years of development in combustion engines, the attractiveness of these powerplants still gains a great deal of attention. The efficiency of engines has been increased continuously through numerous innovations during the last years. Especially in the field of motor engineering, consequent friction optimization leads to cost-effective fuel consumption advantages and a CO2 reduction. This is the motivation and adjusting lever of NANOSLIDE® from Mercedes-Benz. The twin wire arc-spraying process of the aluminum bore creates a thin, iron-carbon-alloyed coating which is surface-finished through honing. Due to the continuous development in engines, the coating strategies must be adapted in parallel to achieve a quality-conformed coating result. The most important factors to this end are the controlled indemnification of a minimal coating thickness and a homogeneous coating deposition of the complete bore. A specific system enables the measuring and adjusting of the part and the central plunging of the coating torch into the bore to achieve a homogeneous coating thickness. Before and after measurement of the bore diameter enables conclusions about the coating thickness. A software tool specifically developed for coating deposition can transfer this information to a model that predicts the coating deposition as a function of the coating strategy.

  10. Tape the Teacher: Easier Field Trips for Large Classes

    ERIC Educational Resources Information Center

    Carter, Lynne; And Others

    1974-01-01

    Describes a tape-guided field trip that has been used successfully with college biology students in the University of California Botanical Garden. This program enables large numbers of students to make individual biological observations in the field with the aid of a specially tailored, taped guide. (JR)

  11. Performance of a 14-T CuNb/Nb3Sn Rutherford coil with a 300 mm wide cold bore

    NASA Astrophysics Data System (ADS)

    Oguro, Hidetoshi; Watanabe, Kazuo; Awaji, Satoshi; Hanai, Satoshi; Ioka, Shigeru; Sugimoto, Masahiro; Tsubouchi, Hirokazu

    2016-08-01

    A large-bore 14-T CuNb/Nb3Sn Rutherford coil was developed for a 25 T cryogen-free superconducting magnet. The magnet consisted of a low-temperature superconducting (LTS) magnet of NbTi and Nb3Sn Rutherford coils, and a high-temperature superconducting magnet. The Nb3Sn Rutherford coil was fabricated by the react-and-wind method for the first time. The LTS magnet reached the designed operation current of 854 A without a training quench at a 1 h ramp rate. The central magnetic field generated by the LTS magnet was measured by a Hall sensor to be 14.0 T at 854 A in a 300 mm cold bore.

  12. Magnetic Helicity and Large Scale Magnetic Fields: A Primer

    NASA Astrophysics Data System (ADS)

    Blackman, Eric G.

    2015-05-01

    Magnetic fields of laboratory, planetary, stellar, and galactic plasmas commonly exhibit significant order on large temporal or spatial scales compared to the otherwise random motions within the hosting system. Such ordered fields can be measured in the case of planets, stars, and galaxies, or inferred indirectly by the action of their dynamical influence, such as jets. Whether large scale fields are amplified in situ or a remnant from previous stages of an object's history is often debated for objects without a definitive magnetic activity cycle. Magnetic helicity, a measure of twist and linkage of magnetic field lines, is a unifying tool for understanding large scale field evolution for both mechanisms of origin. Its importance stems from its two basic properties: (1) magnetic helicity is typically better conserved than magnetic energy; and (2) the magnetic energy associated with a fixed amount of magnetic helicity is minimized when the system relaxes this helical structure to the largest scale available. Here I discuss how magnetic helicity has come to help us understand the saturation of and sustenance of large scale dynamos, the need for either local or global helicity fluxes to avoid dynamo quenching, and the associated observational consequences. I also discuss how magnetic helicity acts as a hindrance to turbulent diffusion of large scale fields, and thus a helper for fossil remnant large scale field origin models in some contexts. I briefly discuss the connection between large scale fields and accretion disk theory as well. The goal here is to provide a conceptual primer to help the reader efficiently penetrate the literature.

  13. Large Field Visualization with Demand-Driven Calculation

    NASA Technical Reports Server (NTRS)

    Moran, Patrick J.; Henze, Chris

    1999-01-01

    We present a system designed for the interactive definition and visualization of fields derived from large data sets: the Demand-Driven Visualizer (DDV). The system allows the user to write arbitrary expressions to define new fields, and then apply a variety of visualization techniques to the result. Expressions can include differential operators and numerous other built-in functions, ail of which are evaluated at specific field locations completely on demand. The payoff of following a demand-driven design philosophy throughout becomes particularly evident when working with large time-series data, where the costs of eager evaluation alternatives can be prohibitive.

  14. Attitude Estimation for Large Field-of-View Sensors

    NASA Technical Reports Server (NTRS)

    Cheng, Yang; Crassidis, John L.; Markley, F. Landis

    2005-01-01

    The QUEST measurement noise model for unit vector observations has been widely used in spacecraft attitude estimation for more than twenty years. It was derived under the approximation that the noise lies in the tangent plane of the respective unit vector and is axially symmetrically distributed about the vector. For large field-of-view sensors, however, this approximation may be poor, especially when the measurement falls near the edge of the field of view. In this paper a new measurement noise model is derived based on a realistic noise distribution in the focal-plane of a large field-of-view sensor, which shows significant differences from the QUEST model for unit vector observations far away from the sensor boresight. An extended Kalman filter for attitude estimation is then designed with the new measurement noise model. Simulation results show that with the new measurement model the extended Kalman filter achieves better estimation performance using large field-of-view sensor observations.

  15. Beginning of Universe through large field hybrid inflation

    NASA Astrophysics Data System (ADS)

    Kobayashi, Tatsuo; Seto, Osamu

    2015-06-01

    Recent detection of B-mode polarization induced from tensor perturbations by the BICEP2 experiment implies the so-called large field inflation, where an inflaton field takes super-Planckian expectation value during inflation, at a high energy scale. We show however, if another inflation follows hybrid inflation, the hybrid inflation can generate a large tensor perturbation with not super-Planckian but Planckian field value. This scenario would relax the tension between BICEP2 and Planck concerning the tensor-to-scalar ratio, because a negative large running can also be obtained for a certain number of e-fold of the hybrid inflation. A natural interpretation of a large gravitational wave mode with or without the scalar spectral running might be multiple inflation in the early Universe.

  16. Highly effective action from large N gauge fields

    NASA Astrophysics Data System (ADS)

    Yang, Hyun Seok

    2014-10-01

    Recently Schwarz put forward a conjecture that the world-volume action of a probe D3-brane in an AdS5×S5 background of type IIB superstring theory can be reinterpreted as the highly effective action (HEA) of four-dimensional N =4 superconformal field theory on the Coulomb branch. We argue that the HEA can be derived from the noncommutative (NC) field theory representation of the AdS/CFT correspondence and the Seiberg-Witten (SW) map defining a spacetime field redefinition between ordinary and NC gauge fields. It is based only on the well-known facts that the master fields of large N matrices are higher-dimensional NC U(1) gauge fields and the SW map is a local coordinate transformation eliminating U(1) gauge fields known as the Darboux theorem in symplectic geometry.

  17. Large amplitude middle atmospheric electric fields - Fact or fiction?

    NASA Technical Reports Server (NTRS)

    Kelley, M. C.; Siefring, C. L.; Pfaff, R. F., Jr.

    1983-01-01

    An analysis of the measurements of large apparent dc fields in the middle atmosphere, previously gathered by two sounding rockets, shows these fields to be spurious. In the case of one of the rockets, the evidence presented suggests that the measured electric fields, aligned with the rocket's velocity vector, may be due to a negatively charged wake. A comparison of measurements made by various electric field booms also suggests that the insulating boom coatings in one experiment may have affected the results obtained. It is recommended that insulating coatings should not be used at mesospheric altitudes, because of the detrimental effects that frictional charging may have.

  18. Hole-boring through clouds for laser power beaming

    SciTech Connect

    Lipinski, R.J.; Walter, R.F.

    1994-12-31

    Power beaming to satellites with a ground-based laser can be limited by clouds. Hole-boring through the clouds with a laser has been proposed as a way to overcome this obstacle. This paper reviews the past work on laser hole-boring and concludes that hole-boring for direct beaming to satellites is likely to require 10--100 MW. However, it may be possible to use an airborne relay mirror at 10--25 km altitude for some applications in order to extend the range of the laser (e.g., for beaming to satellites near the horizon). In these cases, use of the relay mirror also would allow a narrow beam between the laser and the relay, as well as the possibility of reducing the crosswind if the plane matched speed with the cloud temporarily. Under these conditions, the power requirement to bore a hole through most cirrus and cirrostratus clouds might be only 500-kW if the hole is less than 1 m in diameter and if the crosswind speed is less than 10 m/s. Overcoming cirrus and cirrostratus clouds would reduce the downtime due to weather by a factor of 2. However, 500 kW is a large laser, and it may be more effective instead to establish a second power beaming site in a separate weather zone. An assessment of optimum wavelengths for hole boring also was made, and the best options were found to be 3.0--3.4 {mu}m and above 10 {mu}m.

  19. SU-E-J-03: Characterization of the Precision and Accuracy of a New, Preclinical, MRI-Guided Focused Ultrasound System for Image-Guided Interventions in Small-Bore, High-Field Magnets

    SciTech Connect

    Ellens, N; Farahani, K

    2015-06-15

    Purpose: MRI-guided focused ultrasound (MRgFUS) has many potential and realized applications including controlled heating and localized drug delivery. The development of many of these applications requires extensive preclinical work, much of it in small animal models. The goal of this study is to characterize the spatial targeting accuracy and reproducibility of a preclinical high field MRgFUS system for thermal ablation and drug delivery applications. Methods: The RK300 (FUS Instruments, Toronto, Canada) is a motorized, 2-axis FUS positioning system suitable for small bore (72 mm), high-field MRI systems. The accuracy of the system was assessed in three ways. First, the precision of the system was assessed by sonicating regular grids of 5 mm squares on polystyrene plates and comparing the resulting focal dimples to the intended pattern, thereby assessing the reproducibility and precision of the motion control alone. Second, the targeting accuracy was assessed by imaging a polystyrene plate with randomly drilled holes and replicating the hole pattern by sonicating the observed hole locations on intact polystyrene plates and comparing the results. Third, the practicallyrealizable accuracy and precision were assessed by comparing the locations of transcranial, FUS-induced blood-brain-barrier disruption (BBBD) (observed through Gadolinium enhancement) to the intended targets in a retrospective analysis of animals sonicated for other experiments. Results: The evenly-spaced grids indicated that the precision was 0.11 +/− 0.05 mm. When image-guidance was included by targeting random locations, the accuracy was 0.5 +/− 0.2 mm. The effective accuracy in the four rodent brains assessed was 0.8 +/− 0.6 mm. In all cases, the error appeared normally distributed (p<0.05) in both orthogonal axes, though the left/right error was systematically greater than the superior/inferior error. Conclusions: The targeting accuracy of this device is sub-millimeter, suitable for many

  20. Bores and Swash on Natural Beaches.

    DTIC Science & Technology

    1982-07-01

    bore is one in which the ratio of bore height to the r height of the associated wave crest is greater than 0.5. The following section examines data...bores which often traversed the width of the surf zone without interference from following waves . It was often possible to relate swashes to individual...height and wave celerity in the surf zone’, Jour. Geophys. Res., Vol 82, pp 1419-1424. ."-... Sutherland, A.J., Sharma, J.N, and Shemdin , O.H., 1976, " Wave

  1. Stability of large scale chromomagnetic fields in the early universe

    NASA Astrophysics Data System (ADS)

    Elmfors, Per; Persson, David

    1999-01-01

    It is well known that Yang-Mills theory in vacuum has a perturbative instability to spontaneously form a large scale magnetic field (the Savvidy mechanism) and that a constant field is unstable so that a possible ground state has to be inhomogenous over the non-perturbative scale Λ (the Copenhagen vacuum). We argue that this spontaneous instability does not occur at high temperature when the induced field strength gB~Λ2 is much weaker than the magnetic mass squared (g2T)2. At high temperature, oscillations of gauge fields acquire a thermal mass M~gT and we show that this mass stabilizes a magnetic field which is constant over length scales shorter than the magnetic screening length (g2T)-1. We therefore conclude that there is no indication for any spontaneous generation of weak non-abelian magnetic fields in the early universe.

  2. Osedax borings in fossil marine bird bones

    NASA Astrophysics Data System (ADS)

    Kiel, Steffen; Kahl, Wolf-Achim; Goedert, James L.

    2011-01-01

    The bone-eating marine annelid Osedax consumes mainly whale bones on the deep-sea floor, but recent colonization experiments with cow bones and molecular age estimates suggesting a possible Cretaceous origin of Osedax indicate that this worm might be able grow on a wider range of substrates. The suggested Cretaceous origin was thought to imply that Osedax could colonize marine reptile or fish bones, but there is currently no evidence that Osedax consumes bones other than those of mammals. We provide the first evidence that Osedax was, and most likely still is, able to consume non-mammalian bones, namely bird bones. Borings resembling those produced by living Osedax were found in bones of early Oligocene marine flightless diving birds (family Plotopteridae). The species that produced these boreholes had a branching filiform root that grew to a length of at least 3 mm, and lived in densities of up to 40 individuals per square centimeter. The inclusion of bird bones into the diet of Osedax has interesting implications for the recent suggestion of a Cretaceous origin of this worm because marine birds have existed continuously since the Cretaceous. Bird bones could have enabled this worm to survive times in the Earth's history when large marine vertebrates other than fish were rare, specifically after the disappearance of large marine reptiles at the end-Cretaceous mass extinction event and before the rise of whales in the Eocene.

  3. Osedax borings in fossil marine bird bones.

    PubMed

    Kiel, Steffen; Kahl, Wolf-Achim; Goedert, James L

    2011-01-01

    The bone-eating marine annelid Osedax consumes mainly whale bones on the deep-sea floor, but recent colonization experiments with cow bones and molecular age estimates suggesting a possible Cretaceous origin of Osedax indicate that this worm might be able grow on a wider range of substrates. The suggested Cretaceous origin was thought to imply that Osedax could colonize marine reptile or fish bones, but there is currently no evidence that Osedax consumes bones other than those of mammals. We provide the first evidence that Osedax was, and most likely still is, able to consume non-mammalian bones, namely bird bones. Borings resembling those produced by living Osedax were found in bones of early Oligocene marine flightless diving birds (family Plotopteridae). The species that produced these boreholes had a branching filiform root that grew to a length of at least 3 mm, and lived in densities of up to 40 individuals per square centimeter. The inclusion of bird bones into the diet of Osedax has interesting implications for the recent suggestion of a Cretaceous origin of this worm because marine birds have existed continuously since the Cretaceous. Bird bones could have enabled this worm to survive times in the Earth's history when large marine vertebrates other than fish were rare, specifically after the disappearance of large marine reptiles at the end-Cretaceous mass extinction event and before the rise of whales in the Eocene.

  4. Piezoelectric annular array for large depth of field photoacoustic imaging

    PubMed Central

    Passler, K.; Nuster, R.; Gratt, S.; Burgholzer, P.; Paltauf, G.

    2011-01-01

    A piezoelectric detection system consisting of an annular array is investigated for large depth of field photoacoustic imaging. In comparison to a single ring detection system, X-shaped imaging artifacts are suppressed. Sensitivity and image resolution studies are performed in simulations and in experiments and compared to a simulated spherical detector. In experiment an eight ring detection systems offers an extended depth of field over a range of 16 mm with almost constant lateral resolution. PMID:21991555

  5. Turbulent amplification of large-scale magnetic fields

    NASA Technical Reports Server (NTRS)

    Montgomery, D.; Chen, H.

    1984-01-01

    Previously-introduced methods for analytically estimating the effects of small-scale turbulent fluctuations on large-scale dynamics are extended to fully three-dimensional magnetohydrodynamics. The problem becomes algebraically tractable in the presence of sufficiently large spectral gaps. The calculation generalizes 'alpha dynamo' calculations, except that the velocity fluctuations and magnetic fluctuations are treated on an independent and equal footing. Earlier expressions for the 'alpha coefficients' of turbulent magnetic field amplification are recovered as a special case.

  6. An artificial compound eye system for large field imaging

    NASA Astrophysics Data System (ADS)

    Liu, Yan; Shi, Lifang; Shi, Ruiying; Dong, Xiaochun; Deng, Qiling; Du, Chunlei

    2012-11-01

    With the rapid development of science and technology, optical imaging system has been widely used, and the performance requirements are getting higher and higher such as lighter weight, smaller size, larger field of view and more sensitive to the moving targets. With the advantages of large field of view, high agility and multi-channels, compound eye is more and more concerned by academia and industry. In this work, an artificial spherical compound eye imaging system is proposed, which is formed by several mini cameras to get a large field of view. By analyzing the relationship of the view field between every single camera and the whole system, the geometric arrangement of cameras is studied and the compound eye structure is designed. By using the precision machining technology, the system can be manufactured. To verify the performance of this system, experiments were carried out, where the compound eye was formed by seven mini cameras which were placed centripetally along a spherical surface so that each camera points in a different direction. Pictures taken by these cameras were mosaiced into a complete image with large field of view. The results of the experiments prove the validity of the design method and the fabrication technology. By increasing the number of the cameras, larger view field even panoramic imaging can be realized by using this artificial compound eye.

  7. Ultralow-Frequency Magnetic Fields Preceding Large Earthquakes

    NASA Astrophysics Data System (ADS)

    Fraser-Smith, Antony C.

    2008-06-01

    The Great Alaska Earthquake (M 9.2) of 27 March 1964 was the largest earthquake ever to strike the United States in modern times and one of the largest ever recorded anywhere. Later that year, Moore [1964], in a surprisingly rarely cited paper, reported the occurrence of strong ultralow-frequency (ULF; <=10 hertz) magnetic field disturbances at Kodiak, Alaska, in the 1.2 hours before the earthquake. That report has since been followed by others [Fraser-Smith et al., 1990; Kopytenko et al., 1993; Hayakawa et al., 1996; see also Molchanov et al., 1992] similarly describing the occurrence of large-amplitude ULF magnetic field fluctuations before other large earthquakes (``large'' describes earthquakes with magnitudes M ~ 7 or greater). These reports involving four separate, large earthquakes were made by four different groups and the results were published in well-known, refereed scientific journals, so there is no doubt that there is evidence for the existence of comparatively large ULF magnetic field fluctuations preceding large earthquakes.

  8. Small diameter, deep bore optical inspection system

    DOEpatents

    Lord, David E.; Petrini, Richard R.; Carter, Gary W.

    1981-01-01

    An improved rod optic system for inspecting small diameter, deep bores. The system consists of a rod optic system utilizing a curved mirror at the end of the rod lens such that the optical path through the system is bent 90.degree. to minimize optical distortion in examining the sides of a curved bore. The system is particularly useful in the examination of small bores for corrosion, and is capable of examining 1/16 inch diameter and up to 4 inch deep drill holes, for example. The positioning of the curved mirror allows simultaneous viewing from shallow and right angle points of observation of the same artifact (such as corrosion) in the bore hole. The improved rod optic system may be used for direct eye sighting, or in combination with a still camera or a low-light television monitor; particularly low-light color television.

  9. Small diameter, deep bore optical inspection system

    DOEpatents

    Lord, D.E.; Petrini, R.R.; Carter, G.W.

    An improved rod optic system for inspecting small diameter, deep bores is described. The system consists of a rod optic system utilizing a curved mirror at the end of the rod lens such that the optical path through the system is bent 90/sup 0/ to minimize optical distortion in examing the sides of a curved bore. The system is particularly useful in the examination of small bores for corrosion, and is capable if examing 1/16 inch diameter and up to 4-inch deep drill holes, for example. The positioning of the curved mirror allows simultaneous viewing from shallow and righ angle points of observation of the same artifact (such as corrosion) in the bore hole. The improved rod optic system may be used for direct eye sighting, or in combination with a still camera or a low-light television monitor; particularly low-light color television.

  10. High temperature well bore cement slurry

    SciTech Connect

    Nahm, J.J.W.; Vinegar, H.J.; Karanikas, J.M.; Wyant, R.E.

    1993-07-13

    A low density well bore cement slurry composition is described suitable for cementing well bores with high reservoir temperatures comprising: (a) a high alumina cement in an amount of about 40 pounds per barrel of slurry or greater: (b) graphite in an amount greater than about one quarter, by volume, of the solids in the cement slurry; and (c) and a carrier fluid comprising drilling mud.

  11. Scalable parallel distance field construction for large-scale applications

    SciTech Connect

    Yu, Hongfeng; Xie, Jinrong; Ma, Kwan -Liu; Kolla, Hemanth; Chen, Jacqueline H.

    2015-10-01

    Computing distance fields is fundamental to many scientific and engineering applications. Distance fields can be used to direct analysis and reduce data. In this paper, we present a highly scalable method for computing 3D distance fields on massively parallel distributed-memory machines. Anew distributed spatial data structure, named parallel distance tree, is introduced to manage the level sets of data and facilitate surface tracking overtime, resulting in significantly reduced computation and communication costs for calculating the distance to the surface of interest from any spatial locations. Our method supports several data types and distance metrics from real-world applications. We demonstrate its efficiency and scalability on state-of-the-art supercomputers using both large-scale volume datasets and surface models. We also demonstrate in-situ distance field computation on dynamic turbulent flame surfaces for a petascale combustion simulation. In conclusion, our work greatly extends the usability of distance fields for demanding applications.

  12. CONSTRAINING PRIMORDIAL MAGNETIC FIELDS THROUGH LARGE-SCALE STRUCTURE

    SciTech Connect

    Kahniashvili, Tina; Natarajan, Aravind; Battaglia, Nicholas; Maravin, Yurii; Tevzadze, Alexander G.

    2013-06-10

    We study primordial magnetic field effects on the matter perturbations in the universe. We assume magnetic field generation prior to the big bang nucleosynthesis (BBN), i.e., during the radiation-dominated epoch of the universe expansion, but do not limit analysis by considering a particular magnetogenesis scenario. Contrary to previous studies, we limit the total magnetic field energy density and not the smoothed amplitude of the magnetic field at large (of the order of 1 Mpc) scales. We review several cosmological signatures, such as halo abundance, thermal Sunyaev-Zel'dovich effect, and Ly{alpha} data. For a cross-check, we compare our limits with that obtained through the cosmic microwave background faraday rotation effect and BBN. The limits range between 1.5 nG and 4.5 nG for n{sub B} in (- 3; -1.5).

  13. A 30 T pulsed magnet with conical bore for synchrotron powder diffraction.

    PubMed

    Billette, J; Duc, F; Frings, P; Nardone, M; Zitouni, A; Detlefs, C; Roth, T; Crichton, W; Lorenzo, J E; Rikken, G L J A

    2012-04-01

    We report on the design, construction, and operation of a horizontal field, 30 T magnet system with a conical bore optimized for synchrotron x-ray powder diffraction. The magnet offers ±31° optical access downstream of the sample, which allows to measure a sufficiently large number of Debye rings for an accurate crystal structure analysis. Combined with a 290 kJ generator, magnetic field pulses of 60 ms length were generated in the magnet, with a rise time of 4.1 ms and a repetition rate of 6 pulses/h at 30 T. The coil is mounted inside a liquid nitrogen bath. A liquid helium flow cryostat reaches into the coil and allows sample temperature between 5 and 250 K. The setup was used on the European Synchrotron Radiation Facility beamlines ID20 and ID06.

  14. A 30 T pulsed magnet with conical bore for synchrotron powder diffraction

    NASA Astrophysics Data System (ADS)

    Billette, J.; Duc, F.; Frings, P.; Nardone, M.; Zitouni, A.; Detlefs, C.; Roth, T.; Crichton, W.; Lorenzo, J. E.; Rikken, G. L. J. A.

    2012-04-01

    We report on the design, construction, and operation of a horizontal field, 30 T magnet system with a conical bore optimized for synchrotron x-ray powder diffraction. The magnet offers ±31° optical access downstream of the sample, which allows to measure a sufficiently large number of Debye rings for an accurate crystal structure analysis. Combined with a 290 kJ generator, magnetic field pulses of 60 ms length were generated in the magnet, with a rise time of 4.1 ms and a repetition rate of 6 pulses/h at 30 T. The coil is mounted inside a liquid nitrogen bath. A liquid helium flow cryostat reaches into the coil and allows sample temperature between 5 and 250 K. The setup was used on the European Synchrotron Radiation Facility beamlines ID20 and ID06.

  15. Modeling emergent large-scale structures of barchan dune fields

    NASA Astrophysics Data System (ADS)

    Worman, S. L.; Murray, A. B.; Littlewood, R.; Andreotti, B.; Claudin, P.

    2013-10-01

    In nature, barchan dunes typically exist as members of larger fields that display striking, enigmatic structures that cannot be readily explained by examining the dynamics at the scale of single dunes, or by appealing to patterns in external forcing. To explore the possibility that observed structures emerge spontaneously as a collective result of many dunes interacting with each other, we built a numerical model that treats barchans as discrete entities that interact with one another according to simplified rules derived from theoretical and numerical work and from field observations: (1) Dunes exchange sand through the fluxes that leak from the downwind side of each dune and are captured on their upstream sides; (2) when dunes become sufficiently large, small dunes are born on their downwind sides (`calving'); and (3) when dunes collide directly enough, they merge. Results show that these relatively simple interactions provide potential explanations for a range of field-scale phenomena including isolated patches of dunes and heterogeneous arrangements of similarly sized dunes in denser fields. The results also suggest that (1) dune field characteristics depend on the sand flux fed into the upwind boundary, although (2) moving downwind, the system approaches a common attracting state in which the memory of the upwind conditions vanishes. This work supports the hypothesis that calving exerts a first-order control on field-scale phenomena; it prevents individual dunes from growing without bound, as single-dune analyses suggest, and allows the formation of roughly realistic, persistent dune field patterns.

  16. Modeling emergent large-scale structures of barchan dune fields

    NASA Astrophysics Data System (ADS)

    Worman, S. L.; Murray, A.; Littlewood, R. C.; Andreotti, B.; Claudin, P.

    2013-12-01

    In nature, barchan dunes typically exist as members of larger fields that display striking, enigmatic structures that cannot be readily explained by examining the dynamics at the scale of single dunes, or by appealing to patterns in external forcing. To explore the possibility that observed structures emerge spontaneously as a collective result of many dunes interacting with each other, we built a numerical model that treats barchans as discrete entities that interact with one another according to simplified rules derived from theoretical and numerical work, and from field observations: Dunes exchange sand through the fluxes that leak from the downwind side of each dune and are captured on their upstream sides; when dunes become sufficiently large, small dunes are born on their downwind sides ('calving'); and when dunes collide directly enough, they merge. Results show that these relatively simple interactions provide potential explanations for a range of field-scale phenomena including isolated patches of dunes and heterogeneous arrangements of similarly sized dunes in denser fields. The results also suggest that (1) dune field characteristics depend on the sand flux fed into the upwind boundary, although (2) moving downwind, the system approaches a common attracting state in which the memory of the upwind conditions vanishes. This work supports the hypothesis that calving exerts a first order control on field-scale phenomena; it prevents individual dunes from growing without bound, as single-dune analyses suggest, and allows the formation of roughly realistic, persistent dune field patterns.

  17. Numerically modelling the large scale coronal magnetic field

    NASA Astrophysics Data System (ADS)

    Panja, Mayukh; Nandi, Dibyendu

    2016-07-01

    The solar corona spews out vast amounts of magnetized plasma into the heliosphere which has a direct impact on the Earth's magnetosphere. Thus it is important that we develop an understanding of the dynamics of the solar corona. With our present technology it has not been possible to generate 3D magnetic maps of the solar corona; this warrants the use of numerical simulations to study the coronal magnetic field. A very popular method of doing this, is to extrapolate the photospheric magnetic field using NLFF or PFSS codes. However the extrapolations at different time intervals are completely independent of each other and do not capture the temporal evolution of magnetic fields. On the other hand full MHD simulations of the global coronal field, apart from being computationally very expensive would be physically less transparent, owing to the large number of free parameters that are typically used in such codes. This brings us to the Magneto-frictional model which is relatively simpler and computationally more economic. We have developed a Magnetofrictional Model, in 3D spherical polar co-ordinates to study the large scale global coronal field. Here we present studies of changing connectivities between active regions, in response to photospheric motions.

  18. A wind tunnel application of large-field focusing schlieren

    NASA Technical Reports Server (NTRS)

    Ponton, Michael K.; Seiner, John M.; Mitchell, L. K.; Manning, James C.; Jansen, Bernard J.; Lagen, Nicholas T.

    1992-01-01

    A large-field focusing schlieren apparatus was installed in the NASA Lewis Research Center 9 by 15 foot wind tunnel in an attempt to determine the density gradient flow field of a free jet issuing from a supersonic nozzle configuration. The nozzle exit geometry was designed to reduce acoustic emissions from the jet by enhancing plume mixing. Thus, the flow exhibited a complex three-dimensional structure which warranted utilizing the sharp focusing capability of this type of schlieren method. Design considerations concerning tunnel limitations, high-speed photography, and video tape recording are presented in the paper.

  19. Large N correlation functions in superconformal field theories

    NASA Astrophysics Data System (ADS)

    Rodriguez-Gomez, Diego; Russo, Jorge G.

    2016-06-01

    We compute correlation functions of chiral primary operators in mathcal{N}=2 super-conformal theories at large N using a construction based on supersymmetric localization recently developed by Gerchkovitz et al. We focus on mathcal{N}=4 SYM as well as on supercon-formal QCD. In the case of mathcal{N}=4 we recover the free field theory results as expected due to non-renormalization theorems. In the case of superconformal QCD we study the planar expansion in the large N limit. The final correlators admit a simple generalization to a finite N formula which exactly matches the various small N results in the literature.

  20. Large-field high-resolution mosaic movies

    NASA Astrophysics Data System (ADS)

    Hammerschlag, Robert H.; Sliepen, Guus; Bettonvil, Felix C. M.; Jägers, Aswin P. L.; Sütterlin, Peter; Martin, Sara F.

    2012-09-01

    Movies with fields-of-view larger than normal for high-resolution telescopes will give a better understanding of processes on the Sun, such as filament and active region developments and their possible interactions. New active regions can influence, by their emergence, their environment to the extent of possibly serving as an igniter of the eruption of a nearby filament. A method to create a large field-of-view is to join several fields-of-view into a mosaic. Fields are imaged quickly one after another using fast telescope-pointing. Such a pointing cycle has been automated at the Dutch Open Telescope (DOT), a high-resolution solar telescope located on the Canary Island La Palma. The observer can draw with the computer mouse the desired total field in the guider-telescope image of the whole Sun. The guider telescope is equipped with an H-alpha filter and electronic enhancement of contrast in the image for good visibility of filaments and prominences. The number and positions of the subfields are calculated automatically and represented by an array of bright points indicating the subfield centers inside the drawn rectangle of the total field on the computer screen with the whole-sun image. When the exposures start the telescope repeats automatically the sequence of subfields. Automatic production of flats is also programmed including defocusing and fast motion over the solar disk of the image field. For the first time mosaic movies were programmed from stored information on automated telescope motions from one field to the next. The mosaic movies fill the gap between whole-sun images with limited resolution of synoptic telescopes including space instruments and small-field high-cadence movies of high-resolution solar telescopes.

  1. 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.

  2. The propagation of internal undular bores over variable topography

    NASA Astrophysics Data System (ADS)

    Grimshaw, R.; Yuan, C.

    2016-10-01

    In the coastal ocean, large amplitude, horizontally propagating internal wave trains are commonly observed. These are long nonlinear waves and can be modelled by equations of the Korteweg-de Vries type. Typically they occur in regions of variable bottom topography when the variable-coefficient Korteweg-de Vries equation is an appropriate model. Of special interest is the situation when the coefficient of the quadratic nonlinear term changes sign at a certain critical point. This case has been widely studied for a solitary wave, which is extinguished at the critical point and replaced by a train of solitary waves of the opposite polarity to the incident wave, riding on a pedestal of the original polarity. Here we examine the same situation for an undular bore, represented by a modulated periodic wave train. Numerical simulations and some asymptotic analysis based on Whitham modulation equations show that the leading solitary waves in the undular bore are destroyed and replaced by a developing rarefaction wave supporting emerging solitary waves of the opposite polarity. In contrast the rear of the undular bore emerges with the same shape, but with reduced wave amplitudes, a shorter overall length scale and moves more slowly.

  3. Large field inflation models from higher-dimensional gauge theories

    NASA Astrophysics Data System (ADS)

    Furuuchi, Kazuyuki; Koyama, Yoji

    2015-02-01

    Motivated by the recent detection of B-mode polarization of CMB by BICEP2 which is possibly of primordial origin, we study large field inflation models which can be obtained from higher-dimensional gauge theories. The constraints from CMB observations on the gauge theory parameters are given, and their naturalness are discussed. Among the models analyzed, Dante's Inferno model turns out to be the most preferred model in this framework.

  4. Relic vector field and CMB large scale anomalies

    SciTech Connect

    Chen, Xingang; Wang, Yi E-mail: yw366@cam.ac.uk

    2014-10-01

    We study the most general effects of relic vector fields on the inflationary background and density perturbations. Such effects are observable if the number of inflationary e-folds is close to the minimum requirement to solve the horizon problem. We show that this can potentially explain two CMB large scale anomalies: the quadrupole-octopole alignment and the quadrupole power suppression. We discuss its effect on the parity anomaly. We also provide analytical template for more detailed data comparison.

  5. Large field inflation models from higher-dimensional gauge theories

    SciTech Connect

    Furuuchi, Kazuyuki; Koyama, Yoji

    2015-02-23

    Motivated by the recent detection of B-mode polarization of CMB by BICEP2 which is possibly of primordial origin, we study large field inflation models which can be obtained from higher-dimensional gauge theories. The constraints from CMB observations on the gauge theory parameters are given, and their naturalness are discussed. Among the models analyzed, Dante’s Inferno model turns out to be the most preferred model in this framework.

  6. Magnetic field geometry of the large globule CB 34

    NASA Astrophysics Data System (ADS)

    Das, A.; Das, H. S.; Medhi, Biman J.; Wolf, S.

    2016-12-01

    We report the results of optical polarimetric observations of a Bok globule CB34 to study magnetic field structure on large scales (105-106 AU), which is combined with archival sub-mm observations to characterize the magnetic field structure of CB34 on small scales (104-105 AU). The optical polarization measurements indicate that the magnetic field in the globule is constrained to a maximum radius of 105 AU around the core, out to densities not smaller than 104 cm^{-3}. Our study is mainly concentrated on two submillimeter cores C1 and C2 of CB34. The direction of magnetic field of core C2 is found to be nearly perpendicular to the CO outflow direction of the globule. The magnetic field of core C1 is almost aligned with the minor axis of the core which is typical for magnetically dominated star formation models. The mean value of offset between the minor axis of core C2 and the outflow direction is found to be 14° which suggests that the direct ion of the outflow is almost aligned with the minor axis of core C2. The magnetic field strength in the plane-of-sky for cores C1 and C2 is estimated to be ≈ 34 μG and ≈ 70 μG.

  7. Improved RF performance of travelling wave MR with a high permittivity dielectric lining of the bore.

    PubMed

    Andreychenko, A; Bluemink, J J; Raaijmakers, A J E; Lagendijk, J J W; Luijten, P R; van den Berg, C A T

    2013-09-01

    Application of travelling wave MR to human body imaging is restricted by the limited peak power of the available RF amplifiers. Nevertheless, travelling wave MR advantages like a large field of view excitation and distant location of transmit elements would be desirable for whole body MRI. In this work, improvement of the B1+ efficiency of travelling wave MR is demonstrated. High permittivity dielectric lining placed next to the scanner bore wall effectively reduces attenuation of the travelling wave in the longitudinal direction and at the same time directs the radial power flow toward the load. First, this is shown with an analytical model of a metallic cylindrical waveguide with the dielectric lining next to the wall and loaded with a cylindrical phantom. Simulations and experiments also reveal an increase of B1+ efficiency in the center of the bore for travelling wave MR with a dielectric lining. Phantom experiments show up to a 2-fold gain in B1+ with the dielectric lining. This corresponds to a 4-fold increase in power efficiency of travelling wave MR. In vivo experiments demonstrate an 8-fold signal-to-noise ratio gain with the dielectric lining. Overall, it is shown that dielectric lining is a constructive method to improve efficacy of travelling wave MR.

  8. Robust water/fat separation in the presence of large field inhomogeneities using a graph cut algorithm.

    PubMed

    Hernando, Diego; Kellman, P; Haldar, J P; Liang, Z-P

    2010-01-01

    Water/fat separation is a classical problem for in vivo proton MRI. Although many methods have been proposed to address this problem, robust water/fat separation remains a challenge, especially in the presence of large amplitude of static field inhomogeneities. This problem is challenging because of the nonuniqueness of the solution for an isolated voxel. This paper tackles the problem using a statistically motivated formulation that jointly estimates the complete field map and the entire water/fat images. This formulation results in a difficult optimization problem that is solved effectively using a novel graph cut algorithm, based on an iterative process where all voxels are updated simultaneously. The proposed method has good theoretical properties, as well as an efficient implementation. Simulations and in vivo results are shown to highlight the properties of the proposed method and compare it to previous approaches. Twenty-five cardiac datasets acquired on a short, wide-bore scanner with different slice orientations were used to test the proposed method, which produced robust water/fat separation for these challenging datasets. This paper also shows example applications of the proposed method, such as the characterization of intramyocardial fat.

  9. Robust Water/Fat Separation in the Presence of Large Field Inhomogeneities Using a Graph Cut Algorithm

    PubMed Central

    Hernando, Diego; Kellman, P.; Haldar, J. P.; Liang, Z.-P.

    2012-01-01

    Water/fat separation is a classical problem for in vivo proton MRI. Although many methods have been proposed to address this problem, robust water/fat separation remains a challenge, especially in the presence of large amplitude of static field inhomogeneities. This problem is challenging because of the nonuniqueness of the solution for an isolated voxel. This paper tackles the problem using a statistically motivated formulation that jointly estimates the complete field map and the entire water/fat images. This formulation results in a difficult optimization problem that is solved effectively using a novel graph cut algorithm, based on an iterative process where all voxels are updated simultaneously. The proposed method has good theoretical properties, as well as an efficient implementation. Simulations and in vivo results are shown to highlight the properties of the proposed method and compare it to previous approaches. Twenty-five cardiac datasets acquired on a short, wide-bore scanner with different slice orientations were used to test the proposed method, which produced robust water/fat separation for these challenging datasets. This paper also shows example applications of the proposed method, such as the characterization of intramyocardial fat. PMID:19859956

  10. Scalable parallel distance field construction for large-scale applications

    DOE PAGES

    Yu, Hongfeng; Xie, Jinrong; Ma, Kwan -Liu; ...

    2015-10-01

    Computing distance fields is fundamental to many scientific and engineering applications. Distance fields can be used to direct analysis and reduce data. In this paper, we present a highly scalable method for computing 3D distance fields on massively parallel distributed-memory machines. Anew distributed spatial data structure, named parallel distance tree, is introduced to manage the level sets of data and facilitate surface tracking overtime, resulting in significantly reduced computation and communication costs for calculating the distance to the surface of interest from any spatial locations. Our method supports several data types and distance metrics from real-world applications. We demonstrate itsmore » efficiency and scalability on state-of-the-art supercomputers using both large-scale volume datasets and surface models. We also demonstrate in-situ distance field computation on dynamic turbulent flame surfaces for a petascale combustion simulation. In conclusion, our work greatly extends the usability of distance fields for demanding applications.« less

  11. Full bore internal tieback system and method

    SciTech Connect

    Brammer, N.; Hosie, S.

    1993-06-29

    In a subsea well assembly having a tubular wellhead housing having a bore, the improvement is described comprising in combination: a counterbore in the bore of the wellhead housing; a tieback profile in the counterbore; a protective sleeve releasably secured in the counterbore and covering the tieback profile, the protective sleeve being movable to expose the tieback profile when it is desired to tieback the subsea well assembly; a tieback funnel which is configured to land on the rim of the wellhead housing when it is desired to tieback the subsea well assembly; and a tieback sleeve carried by the tieback funnel, having a profile on its exterior which is configured to engage the tieback profile in the counterbore after the protective sleeve has been moved to secure the tieback funnel to the wellhead housing, the tieback sleeve having a bore that has a diameter at least equal to the diameter of the bore immediately below the counterbore. A method of drilling and tying back a subsea well is described which includes the steps of installing an outer wellhead housing with conductor pipe extending into the well, then drilling the well to a greater depth, the improvement comprising: providing an inner wellhead housing with a bore, a rim, a counterbore extending downward from the rim, a tieback profile in the counterbore, and a sealing area located below the counterbore; releasably installing a protective sleeve in the counterbore so as to cover the tieback profile; securing a string of casing to the inner wellhead housing and landing the inner wellhead housing in the outer wellhead housing; drilling the well to a greater depth with the protective sleeve located in the counterbore; securing another string of casing to a casing hanger, landing the casing hanger in the inner wellhead housing, cementing the second string of casing in the well, and sealing the casing hanger to the sealing area of the bore of the inner wellhead housing.

  12. Planck intermediate results. XLII. Large-scale Galactic magnetic fields

    NASA Astrophysics Data System (ADS)

    Planck Collaboration; Adam, R.; Ade, P. A. R.; Alves, M. I. R.; Ashdown, M.; Aumont, J.; Baccigalupi, C.; Banday, A. J.; Barreiro, R. B.; Bartolo, N.; Battaner, E.; Benabed, K.; Benoit-Lévy, A.; Bernard, J.-P.; Bersanelli, M.; Bielewicz, P.; Bonavera, L.; Bond, J. R.; Borrill, J.; Bouchet, F. R.; Boulanger, F.; Bucher, M.; Burigana, C.; Butler, R. C.; Calabrese, E.; Cardoso, J.-F.; Catalano, A.; Chiang, H. C.; Christensen, P. R.; Colombo, L. P. L.; Combet, C.; Couchot, F.; Crill, B. P.; Curto, A.; Cuttaia, F.; Danese, L.; Davis, R. J.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Dickinson, C.; Diego, J. M.; Dolag, K.; Doré, O.; Ducout, A.; Dupac, X.; Elsner, F.; Enßlin, T. A.; Eriksen, H. K.; Ferrière, K.; Finelli, F.; Forni, O.; Frailis, M.; Fraisse, A. A.; Franceschi, E.; Galeotta, S.; Ganga, K.; Ghosh, T.; Giard, M.; Gjerløw, E.; González-Nuevo, J.; Górski, K. M.; Gregorio, A.; Gruppuso, A.; Gudmundsson, J. E.; Hansen, F. K.; Harrison, D. L.; Hernández-Monteagudo, C.; Herranz, D.; Hildebrandt, S. R.; Hobson, M.; Hornstrup, A.; Hurier, G.; Jaffe, A. H.; Jaffe, T. R.; Jones, W. C.; Juvela, M.; Keihänen, E.; Keskitalo, R.; Kisner, T. S.; Knoche, J.; Kunz, M.; Kurki-Suonio, H.; Lamarre, J.-M.; Lasenby, A.; Lattanzi, M.; Lawrence, C. R.; Leahy, J. P.; Leonardi, R.; Levrier, F.; Liguori, M.; Lilje, P. B.; Linden-Vørnle, M.; López-Caniego, M.; Lubin, P. M.; Macías-Pérez, J. F.; Maggio, G.; Maino, D.; Mandolesi, N.; Mangilli, A.; Maris, M.; Martin, P. G.; Martínez-González, E.; Masi, S.; Matarrese, S.; Melchiorri, A.; Mennella, A.; Migliaccio, M.; Miville-Deschênes, M.-A.; Moneti, A.; Montier, L.; Morgante, G.; Munshi, D.; Murphy, J. A.; Naselsky, P.; Nati, F.; Natoli, P.; Nørgaard-Nielsen, H. U.; Oppermann, N.; Orlando, E.; Pagano, L.; Pajot, F.; Paladini, R.; Paoletti, D.; Pasian, F.; Perotto, L.; Pettorino, V.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Plaszczynski, S.; Pointecouteau, E.; Polenta, G.; Ponthieu, N.; Pratt, G. W.; Prunet, S.; Puget, J.-L.; Rachen, J. P.; Reinecke, M.; Remazeilles, M.; Renault, C.; Renzi, A.; Ristorcelli, I.; Rocha, G.; Rossetti, M.; Roudier, G.; Rubiño-Martín, J. A.; Rusholme, B.; Sandri, M.; Santos, D.; Savelainen, M.; Scott, D.; Spencer, L. D.; Stolyarov, V.; Stompor, R.; Strong, A. W.; Sudiwala, R.; Sunyaev, R.; Suur-Uski, A.-S.; Sygnet, J.-F.; Tauber, J. A.; Terenzi, L.; Toffolatti, L.; Tomasi, M.; Tristram, M.; Tucci, M.; Valenziano, L.; Valiviita, J.; Van Tent, F.; Vielva, P.; Villa, F.; Wade, L. A.; Wandelt, B. D.; Wehus, I. K.; Yvon, D.; Zacchei, A.; Zonca, A.

    2016-12-01

    Recent models for the large-scale Galactic magnetic fields in the literature have been largely constrained by synchrotron emission and Faraday rotation measures. We use three different but representative models to compare their predicted polarized synchrotron and dust emission with that measured by the Planck satellite. We first update these models to match the Planck synchrotron products using a common model for the cosmic-ray leptons. We discuss the impact on this analysis of the ongoing problems of component separation in the Planck microwave bands and of the uncertain cosmic-ray spectrum. In particular, the inferred degree of ordering in the magnetic fields is sensitive to these systematic uncertainties, and we further show the importance of considering the expected variations in the observables in addition to their mean morphology. We then compare the resulting simulated emission to the observed dust polarization and find that the dust predictions do not match the morphology in the Planck data but underpredict the dust polarization away from the plane. We modify one of the models to roughly match both observables at high latitudes by increasing the field ordering in the thin disc near the observer. Though this specific analysis is dependent on the component separation issues, we present the improved model as a proof of concept for how these studies can be advanced in future using complementary information from ongoing and planned observational projects.

  13. Infrared-temperature variability in a large agricultural field

    NASA Technical Reports Server (NTRS)

    Millard, J. P.; Goettelman, R. C.; Leroy, M. J.

    1981-01-01

    Dunnigan Agro-Meteorological Experiment airborne thermal scanner images of a large varying-terrain barley field are acquired and analyzed. Temperature variability that may occur within instantaneous fields of view (IFOV) is defined (coefficient of variation: standard deviation/mean temperature in degrees C), and the percentage of the area within various IFOV's within + or - 1, 2, 3, and 5 degrees of the mean is determined. With the exception of very rugged terrain, over 80% of the area within 4, 16, 65 and 258 ha cells was at temperatures within + or - 3 C of the mean cell temperature. Remote measurements of field temperature appeared to be slightly influenced by pixel size in the range 4 ha to 259 ha, and the area percentage within any pixel which contributes within + or - 1, 2, 3, and 5 degrees C of the mean, is nominally the same. In conclusion, no great advantage is found in utilizing a small IFOV instead of a large one for remote sensing of crop temperature.

  14. Stress field control during large caldera-forming eruptions

    NASA Astrophysics Data System (ADS)

    Costa, Antonio; Marti, Joan

    2016-10-01

    Crustal stress field can have a significant influence on the way magma is channelled through the crust and erupted explosively at the surface. Large Caldera Forming Eruptions (LCFEs) can erupt hundreds to thousands of cubic kilometres of magma in a relatively short time along fissures under the control of a far-field extensional stress. The associated eruption intensities are estimated in the range 109 - 1011 kg/s. We analyse syn-eruptive dynamics of LCFEs, by simulating numerically explosive flow of magma through a shallow dyke conduit connected to a magma chamber that in turn is fed by a deeper magma reservoir, both under the action of an extensional far-field stress. Results indicate that huge amounts of high viscosity silicic magma can be erupted over timescales of a few to several hours. Our study provides answers to outstanding questions relating to the intensity and duration of catastrophic volcanic eruptions in the past. In addition, it presents far-reaching implications for the understanding of dynamics and intensity of large-magnitude volcanic eruptions on Earth and to highlight the necessity of a future research to advance our knowledge of these rare catastrophic events.

  15. The effective field theory of cosmological large scale structures

    SciTech Connect

    Carrasco, John Joseph M.; Hertzberg, Mark P.; Senatore, Leonardo

    2012-09-20

    Large scale structure surveys will likely become the next leading cosmological probe. In our universe, matter perturbations are large on short distances and small at long scales, i.e. strongly coupled in the UV and weakly coupled in the IR. To make precise analytical predictions on large scales, we develop an effective field theory formulated in terms of an IR effective fluid characterized by several parameters, such as speed of sound and viscosity. These parameters, determined by the UV physics described by the Boltzmann equation, are measured from N-body simulations. We find that the speed of sound of the effective fluid is c2s ≈ 10–6c2 and that the viscosity contributions are of the same order. The fluid describes all the relevant physics at long scales k and permits a manifestly convergent perturbative expansion in the size of the matter perturbations δ(k) for all the observables. As an example, we calculate the correction to the power spectrum at order δ(k)4. As a result, the predictions of the effective field theory are found to be in much better agreement with observation than standard cosmological perturbation theory, already reaching percent precision at this order up to a relatively short scale k ≃ 0.24h Mpc–1.

  16. Two-level systems driven by large-amplitude fields

    NASA Astrophysics Data System (ADS)

    Nori, F.; Ashhab, S.; Johansson, J. R.; Zagoskin, A. M.

    2009-03-01

    We analyze the dynamics of a two-level system subject to driving by large-amplitude external fields, focusing on the resonance properties in the case of driving around the region of avoided level crossing. In particular, we consider three main questions that characterize resonance dynamics: (1) the resonance condition, (2) the frequency of the resulting oscillations on resonance, and (3) the width of the resonance. We identify the regions of validity of different approximations. In a large region of the parameter space, we use a geometric picture in order to obtain both a simple understanding of the dynamics and quantitative results. The geometric approach is obtained by dividing the evolution into discrete time steps, with each time step described by either a phase shift on the basis states or a coherent mixing process corresponding to a Landau-Zener crossing. We compare the results of the geometric picture with those of a rotating wave approximation. We also comment briefly on the prospects of employing strong driving as a useful tool to manipulate two-level systems. S. Ashhab, J.R. Johansson, A.M. Zagoskin, F. Nori, Two-level systems driven by large-amplitude fields, Phys. Rev. A 75, 063414 (2007). S. Ashhab et al, unpublished.

  17. Magnetic Field Anomalies Above Large Martian Impact Structures

    NASA Astrophysics Data System (ADS)

    Langlais, B.; Ostanciaux; Thébault, E.

    2008-12-01

    The Mars Global Surveyor NASA mission revealed the complex nature of the lithospheric magnetic field of Mars. Intense anomalies are located above the southern cratered highlands, while the giant impact basins (Hellas, Argyre, Utopia) and the northern smoothed lowlands do not show significant anomalies. Here we study the magnetic signal above large impact craters, with diameters ranging between 100 and 2000 km. Magnetic measurements are carefully screened and selected to avoid non static features. Then the mean magnetic field is evaluated both inside each crater rim and in its immediate vicinity, within one crater radius. The ratio of these two quantities helps to determine which craters modified the magnetic properties of the pre-impact lithosphere. In addition, this technique allows the impacts located in the strongly magnetized Terra Sirenum and Terra Cimmeria to be studied. Results of this study, as well as comparison of the magnetic measurements to predicted ones for different pre-impact magnetization directions will be presented.

  18. Influence of the Earth's magnetic field on large area photomultipliers

    SciTech Connect

    Leonora, E.; Aiello, S.; Leotta, G.

    2011-07-01

    The influence of the Earth's magnetic field on large area photomultipliers proposed for a future deep sea neutrino telescope was studied under the EU-funded KM3NeT design study. The aims were to evaluate variations in PMT performance in the Earth's magnetic field and to decide whether the use of magnetic shielding is necessary. Measurements were performed on three Hamamatsu PMTs: two 8-inch R5912 types, one of these with super-bi-alkali photocathode, and a 10-inch R7081 type with a standard bi-alkali photocathode. The various characteristics of the PMTs were measured while varying the PMT orientations with respect to the Earth's magnetic field, both with and without a mu-metal cage as magnetic shield. In the 8-inch PMTs the impact of the magnetic field was found to be smaller than that on the 10-inch PMT. The increased quantum efficiency in the 8 super-bi-alkali PMT almost compensated its smaller detection surface compared to the 10' PMT. No significant effects were measured upon transit time and the fraction of spurious pulses. (authors)

  19. Parton physics from large-momentum effective field theory

    NASA Astrophysics Data System (ADS)

    Ji, XiangDong

    2014-07-01

    Parton physics, when formulated as light-front correlations, are difficult to study non-perturbatively, despite the promise of light-front quantization. Recently an alternative approach to partons have been proposed by re-visiting original Feynman picture of a hadron moving at asymptotically large momentum. Here I formulate the approach in the language of an effective field theory for a large hadron momentum P in lattice QCD, LaMET for short. I show that using this new effective theory, parton properties, including light-front parton wave functions, can be extracted from lattice observables in a systematic expansion of 1/ P, much like that the parton distributions can be extracted from the hard scattering data at momentum scales of a few GeV.

  20. Imaging ellipsometer with large field-of-view

    NASA Astrophysics Data System (ADS)

    Gu, Liyuan; Zeng, Aijun; Hu, Shiyu; Yuan, Qiao; Cheng, Weilin; Zhang, Shanhua; Hu, Guohang; He, Hongbo; Huang, Huijie

    2016-11-01

    A polarizer-compensator-sample-analyzer (PCSA) imaging ellipsometer with large field of view is presented. The sample is imaged on a CCD sensor by a telecentric imaging system and its tilt is monitored by an optical autocollimator. The sample, the telecentric imaging system and the CCD sensor satisfy the Scheimpflug condition. In measurement, the light extinction measurement method and the four quadrants average method are used to improve the accuracy. In experiments, a chromium thin film sample is measured by the imaging ellipsometer and a spectroscopic ellipsometer. The measurement results by two ellipsometers are consistent. The usefulness of the imaging ellipsometer is verified.

  1. Vertical boring mill capacity is increased

    NASA Technical Reports Server (NTRS)

    Young, R. J.

    1968-01-01

    Commercially available vertical boring mill with a nominal capacity to 27 feet in diameter of workpiece has been modified in-shop to handle work up to 36 feet in diameter. Capacity was increased by adding extension saddles to the mill support columns on each side.

  2. Field-Effects in Large Axial Ratio Liquid Crystals

    NASA Astrophysics Data System (ADS)

    Lonberg, Franklin J.

    This paper consists of an introduction and four chapters, the abstracts of which are presented below. Chapter 2. The subject of this chapter is the dynamic periodic structures which are observed in the twist Frederiks transition. It is found that, for fields above a material dependent level, a transient periodic distortion is observed. The wave vector is parallel to the unperturbed director and increases with increasing field. A theoretical model and experimental data are presented. Chapter 3. The subject of this chapter is the discovery of a new equilibrium structure in the splay Frederiks transition. Experimental observation has shown that the imposition of a field, just above the critical strength, produces a periodic distortion in the polymer liquid crystal PBG. This periodic state is not dynamic in origin but it is a true ground state. An analysis of the energy of a liquid crystal, in the splay Frederiks transition geometry, shows that in materials with K(,1)/K(,3) > 3.3 the periodic distortion will have a lower critical field than the uniform distortion. Chapter 4. The subject of this chapter is the dynamics of the bend Frederiks transition in large axial ratio nematics. Experimental evidence is presented to show that there is a distortion mode which occurs at field greater than 2H(,c), which is very fast and does not grow exponentially. An analysis of the equations of motion shows that a mode with wave length half that of the static equilibrium mode will have these properties. Chapter 5. The bend Frederiks transition is use to show that the bend and splay elastic constants are linear in concentration in PBG. Interpretation of this result is made in connection with models of the elastic energy in liquid crystal made of semi-flexible partiles.

  3. Spin Chain in Magnetic Field: Limitations of the Large-N Mean-Field Theory

    DOE PAGES

    Wohlfeld, K.; Chen, Cheng-Chien; van Veenendaal, M.; ...

    2015-02-01

    Motivated by the recent success in describing the spin and orbital spectrum of a spin-orbital chain using a large-N mean-field approximation [Phys. Rev. B 91, 165102 (2015)], we apply the same formalism to the case of a spin chain in the external magnetic field. It occurs that in this case, which corresponds to N=2 in the approximation, the large-N mean-field theory cannot qualitatively reproduce the spin excitation spectra at high magnetic fields, which polarize more than 50% of the spins in the magnetic ground state. This, rather counterintuitively, shows that the physics of a spin chain can under some circumstancesmore » be regarded as more complex than the physics of a spin-orbital chain.« less

  4. Spin Chain in Magnetic Field: Limitations of the Large-N Mean-Field Theory

    SciTech Connect

    Wohlfeld, K.; Chen, Cheng-Chien; van Veenendaal, M. ; Devereaux, T. P.

    2015-02-01

    Motivated by the recent success in describing the spin and orbital spectrum of a spin-orbital chain using a large-N mean-field approximation [Phys. Rev. B 91, 165102 (2015)], we apply the same formalism to the case of a spin chain in the external magnetic field. It occurs that in this case, which corresponds to N=2 in the approximation, the large-N mean-field theory cannot qualitatively reproduce the spin excitation spectra at high magnetic fields, which polarize more than 50% of the spins in the magnetic ground state. This, rather counterintuitively, shows that the physics of a spin chain can under some circumstances be regarded as more complex than the physics of a spin-orbital chain.

  5. Field-omics—understanding large-scale molecular data from field crops

    PubMed Central

    Alexandersson, Erik; Jacobson, Dan; Vivier, Melané A.; Weckwerth, Wolfram; Andreasson, Erik

    2014-01-01

    The recent advances in gene expression analysis as well as protein and metabolite quantification enable genome-scale capturing of complex biological processes at the molecular level in crop field trials. This opens up new possibilities for understanding the molecular and environmental complexity of field-based systems and thus shedding light on the black box between genotype and environment, which in agriculture always is influenced by a multi-stress environment and includes management interventions. Nevertheless, combining different types of data obtained from the field and making biological sense out of large datasets remain challenging. Here we highlight the need to create a cross-disciplinary platform for innovative experimental design, sampling and subsequent analysis of large-scale molecular data obtained in field trials. For these reasons we put forward the term field-omics: “Field-omics strives to couple information from genomes, transcriptomes, proteomes, metabolomes and metagenomes to the long-established practice in crop science of conducting field trials as well as to adapt current strategies for recording and analysing field data to facilitate integration with ‘-omics’ data.” PMID:24999347

  6. Large Field Photogrammetry Techniques in Aircraft and Spacecraft Impact Testing

    NASA Technical Reports Server (NTRS)

    Littell, Justin D.

    2010-01-01

    The Landing and Impact Research Facility (LandIR) at NASA Langley Research Center is a 240 ft. high A-frame structure which is used for full-scale crash testing of aircraft and rotorcraft vehicles. Because the LandIR provides a unique capability to introduce impact velocities in the forward and vertical directions, it is also serving as the facility for landing tests on full-scale and sub-scale Orion spacecraft mass simulators. Recently, a three-dimensional photogrammetry system was acquired to assist with the gathering of vehicle flight data before, throughout and after the impact. This data provides the basis for the post-test analysis and data reduction. Experimental setups for pendulum swing tests on vehicles having both forward and vertical velocities can extend to 50 x 50 x 50 foot cubes, while weather, vehicle geometry, and other constraints make each experimental setup unique to each test. This paper will discuss the specific calibration techniques for large fields of views, camera and lens selection, data processing, as well as best practice techniques learned from using the large field of view photogrammetry on a multitude of crash and landing test scenarios unique to the LandIR.

  7. Biomechanics of substrate boring by fig wasps.

    PubMed

    Kundanati, Lakshminath; Gundiah, Namrata

    2014-06-01

    Female insects of diverse orders bore into substrates to deposit their eggs. Such insects must overcome several biomechanical challenges to successfully oviposit, which include the selection of suitable substrates through which the ovipositor can penetrate without itself fracturing. In many cases, the insect may also need to steer and manipulate the ovipositor within the substrate to deliver eggs at desired locations before rapidly retracting her ovipositor to avoid predation. In the case of female parasitoid ichneumonid wasps, this process is repeated multiple times during her lifetime, thus testing the ability of the ovipositioning apparatus to endure fracture and fatigue. What specific adaptations does the ovipositioning apparatus of a female ichneumonoid wasp possess to withstand these challenges? We addressed this question using a model system composed of parasitoid and pollinator fig wasps. First, we show that parasitoid ovipositor tips have teeth-like structures, preferentially enriched with zinc, unlike the smooth morphology of pollinator ovipositors. We describe sensillae present on the parasitoid ovipositor tip that are likely to aid in the detection of chemical species and mechanical deformations and sample microenvironments within the substrate. Second, using atomic force microscopy, we show that parasitoid tip regions have a higher modulus compared with regions proximal to the abdomen in parasitoid and pollinator ovipositors. Finally, we use videography to film wasps during substrate boring and analyse buckling of the ovipositor to estimate the forces required for substrate boring. Together, these results allow us to describe the biomechanical principles underlying substrate boring in parasitoid ichneumonid wasps. Such studies may be useful for the biomimetic design of surgical tools and in the use of novel mechanisms to bore through hard substrates.

  8. Large-scale field trials of active immunizing agents

    PubMed Central

    Cockburn, W. Charles

    1955-01-01

    In this discussion of the methods to be used in large-scale field trials of active immunizing agents and of the results to be expected from such trials, special emphasis is laid on pertussis vaccine trials in Great Britain. After a review of the criteria for strictly controlled field studies and of the investigation of typhoid vaccines conducted in 1904-08 by the Antityphoid Committee of the British Army, the author describes the pertussis vaccine studies which have been and are now being carried by the Whooping-Cough Immunization Committee of the Medical Research Council of Great Britain. The original strictly controlled trials have been completed and the results published. Studies are now being made of vaccines prepared by different methods and evaluated both in the field and in the laboratory. Each vaccine is given to some 2000-3000 children of 4-6 months to 4 years of age. By the end of the studies 30 000-40 000 children will have been followed up for a period of two years. Since in the current studies all the children are vaccinated and none are left as unvaccinated controls, the relative and not the absolute protective value of the vaccines will be measured. PMID:13270079

  9. Rapid topography mapping of scalar fields: Large molecular clusters

    NASA Astrophysics Data System (ADS)

    Yeole, Sachin D.; López, Rafael; Gadre, Shridhar R.

    2012-08-01

    An efficient and rapid algorithm for topography mapping of scalar fields, molecular electron density (MED) and molecular electrostatic potential (MESP) is presented. The highlight of the work is the use of fast function evaluation by Deformed-atoms-in-molecules (DAM) method. The DAM method provides very rapid as well as sufficiently accurate function and gradient evaluation. For mapping the topography of large systems, the molecular tailoring approach (MTA) is invoked. This new code is tested out for mapping the MED and MESP critical points (CP's) of small systems. It is further applied to large molecular clusters viz. (H2O)25, (C6H6)8 and also to a unit cell of valine crystal at MP2/6-31+G(d) level of theory. The completeness of the topography is checked by extensive search as well as applying the Poincaré-Hopf relation. The results obtained show that the DAM method in combination with MTA provides a rapid and efficient route for mapping the topography of large molecular systems.

  10. Field-aligned currents and large-scale magnetospheric electric fields

    NASA Technical Reports Server (NTRS)

    Dangelo, N.

    1979-01-01

    The existence of field-aligned currents (FAC) at northern and southern high latitudes was confirmed by a number of observations, most clearly by experiments on the TRIAD and ISIS 2 satellites. The high-latitude FAC system is used to relate what is presently known about the large-scale pattern of high-latitude ionospheric electric fields and their relation to solar wind parameters. Recently a simplified model was presented for polar cap electric fields. The model is of considerable help in visualizing the large-scale features of FAC systems. A summary of the FAC observations is given. The simplified model is used to visualize how the FAC systems are driven by their generators.

  11. Large field of view multiphoton microscopy of human skin

    NASA Astrophysics Data System (ADS)

    Balu, Mihaela; Mikami, Hideharu; Hou, Jue; Potma, Eric O.; Tromberg, Bruce J.

    2016-03-01

    Clinical examination crucially relies on the ability to quickly examine large tissue areas and rapidly zoom in to regions of interest. Skin lesions often show irregularity in color and appearance in general, especially when they start to progress towards malignancy. Large field of view (FOV) and automatic translation of the imaging area are critical in the assessment of the entire lesion. Imaging of limited FOVs of the lesion can easily result in false negative diagnosis. We present a multiphoton microscope based on two-photon excited fluorescence and second-harmonic generation that images FOVs of about 0.8 mm2 (without stitching adjacent FOVs) at speeds of 10 frames/second (800 x 800 pixels) with lateral and axial resolutions of 0.5 μm and 2.5 μm, respectively. The main novelty of this instrument is the design of the scan head, which includes a fast galvanometric scanner, relay optics, a beam expander and a high NA objective lens. We optimized the system based on the Olympus 25x, 1.05NA water immersion lens, that features a long working distance of 1 mm. Proper tailoring of the beam expander, which consists of the scan and tube lens elements, enables scaling of the FOV. The design criteria include a flat wavefront of the beam, minimum field curvature, and suppressed spherical aberrations. All aberrations in focus are below the Marechal criterion of 0.07λ rms for diffraction-limited performance. We demonstrate the practical utility of this microscope by ex-vivo imaging of wide FOVs in normal human skin.

  12. Inversion of potential fields on nodes for large grids

    NASA Astrophysics Data System (ADS)

    Marcotte, Denis; Shamsipour, Pejman; Coutant, Olivier; Chouteau, Michel

    2014-11-01

    The non-iterative direct inversion of potential field data by stochastic approach enables to incorporate in a coherent way a priori geological knowledge, the known densities on any support size and the gravity data. The weakness of the method is the necessary computation of the parameter covariance matrix. For a large mesh made of prisms, the matrix is simply too large to fit in memory. The new approach approximates the prism covariance matrix by a surrogate matrix computed from the covariance matrix of a reduced set of nodes aimed at representing the whole domain of inversion. Care is taken to preserve the properties of direct stochastic inversion on the whole set of prisms. Hence, the approach accounts in a consistent way for the support effect, the inversion remains exact in the absence of noise on data, point and block known densities are exactly reproduced, any set of linear constraints can be applied, and the inversion is non-iterative in all cases. It is shown on synthetic examples that the number of nodes needs not to be very large to ensure a good approximation of the parameter covariance matrix or to ensure similarity of the inversion solutions. An application to a gravity survey including borehole density data shows the applicability of the method for a large number of cells in the inversion domain. Even with as much as 10,000 nodes and one million prisms, the computing time remained acceptable at less than two hours on a workstation. The inverted solution obtained with the nodes approach is compared to a direct kriging of borehole density data and to direct inversion using only the gravity data. The solution combining both information is different from the inversion using only gravity, but only in the area where borehole data are numerous. Although shown for the gravity-density potential, the approach is general and can be extended to magnetic-susceptibility and joint inversion. The proposed approach helps solving the recurrent problem of the

  13. Two-level systems driven by large-amplitude fields

    SciTech Connect

    Ashhab, S.; Johansson, J. R.; Zagoskin, A. M.; Nori, Franco

    2007-06-15

    We analyze the dynamics of a two-level system subject to driving by large-amplitude external fields, focusing on the resonance properties in the case of driving around the region of avoided level crossing. In particular, we consider three main questions that characterize resonance dynamics: (1) the resonance condition (2) the frequency of the resulting oscillations on resonance, and (3) the width of the resonance. We identify the regions of validity of different approximations. In a large region of the parameter space, we use a geometric picture in order to obtain both a simple understanding of the dynamics and quantitative results. The geometric approach is obtained by dividing the evolution into discrete time steps, with each time step described by either a phase shift on the basis states or a coherent mixing process corresponding to a Landau-Zener crossing. We compare the results of the geometric picture with those of a rotating wave approximation. We also comment briefly on the prospects of employing strong driving as a useful tool to manipulate two-level systems.

  14. Predatorial borings in late precambrian mineralized exoskeletons.

    PubMed

    Bengtson, S; Zhao, Y

    1992-07-17

    The late Precambrian tube-forming Cloudina, the earliest known animal to produce a mineralized exoskeleton, shows evidence of having been attacked by shell-boring organisms. Of more than 500 tubes from Shaanxi Province, China, 2.7% have rounded holes 40 to 400 micrometers in diameter. The relation between the size of the holes and the width of the bored tubes suggests that the attacking organism was a predator, selecting its prey for size. If true, this would be the oldest case of predation in the fossil record and would support the hypothesis that selection pressures from predation was a significant factor in the evolution of animal skeletons around the Precambrian-Cambrian boundary.

  15. General model for boring tool optimization

    NASA Astrophysics Data System (ADS)

    Moraru, G. M.; rbes, M. V. Ze; Popescu, L. G.

    2016-08-01

    Optimizing a tool (and therefore those for boring) consist in improving its performance through maximizing the objective functions chosen by the designer and/or by user. In order to define and to implement the proposed objective functions, contribute numerous features and performance required by tool users. Incorporation of new features makes the cutting tool to be competitive in the market and to meet user requirements.

  16. Experimental stiffness of tapered bore seals

    NASA Technical Reports Server (NTRS)

    Fleming, D. P.

    1985-01-01

    The stiffness of tapered-bore ring seals was measured with air as the sealed fluid. Static stiffness agreed fairly well with results of a previous analysis. Cross-coupled stiffness due to shaft rotation was much less than predicted. It is suggested that part of the disparity may be due to simplifying assumptions in the analysis; however, these do not appear to account for the entire difference observed.

  17. WELL BORE BREAKOUTS AND IN SITU STRESS.

    USGS Publications Warehouse

    Zoback, Mark D.; Moos, Daniel; Mastin, Larry; Anderson, Roger N.

    1985-01-01

    The detailed cross-sectional shape of stress induced well bore breakouts has been studied using specially processed ultrasonic borehole televiewer data. Breakout shapes are shown for a variety of rock types and introduce a simple elastic failure model which explains many features of the observations. Both the observations and calculations indicate that the breakouts define relatively broad and flat curvilinear surfaces which enlarge the borehole in the direction of minimum horizontal compression. Refs.

  18. Undular bore theory for the Gardner equation.

    PubMed

    Kamchatnov, A M; Kuo, Y-H; Lin, T-C; Horng, T-L; Gou, S-C; Clift, R; El, G A; Grimshaw, R H J

    2012-09-01

    We develop modulation theory for undular bores (dispersive shock waves) in the framework of the Gardner, or extended Korteweg-de Vries (KdV), equation, which is a generic mathematical model for weakly nonlinear and weakly dispersive wave propagation, when effects of higher order nonlinearity become important. Using a reduced version of the finite-gap integration method we derive the Gardner-Whitham modulation system in a Riemann invariant form and show that it can be mapped onto the well-known modulation system for the Korteweg-de Vries equation. The transformation between the two counterpart modulation systems is, however, not invertible. As a result, the study of the resolution of an initial discontinuity for the Gardner equation reveals a rich phenomenology of solutions which, along with the KdV-type simple undular bores, include nonlinear trigonometric bores, solibores, rarefaction waves, and composite solutions representing various combinations of the above structures. We construct full parametric maps of such solutions for both signs of the cubic nonlinear term in the Gardner equation. Our classification is supported by numerical simulations.

  19. The biomechanics of burrowing and boring.

    PubMed

    Dorgan, Kelly M

    2015-01-15

    Burrowers and borers are ecosystem engineers that alter their physical environments through bioturbation, bioirrigation and bioerosion. The mechanisms of moving through solid substrata by burrowing or boring depend on the mechanical properties of the medium and the size and morphology of the organism. For burrowing animals, mud differs mechanically from sand; in mud, sediment grains are suspended in an organic matrix that fails by fracture. Macrofauna extend burrows through this elastic mud by fracture. Sand is granular and non-cohesive, enabling grains to more easily move relative to each other, and macrofaunal burrowers use fluidization or plastic rearrangement of grains. In both sand and mud, peristaltic movements apply normal forces and reduce shear. Excavation and localized grain compaction are mechanisms that plastically deform sediments and are effective in both mud and sand, with bulk excavation being used by larger organisms and localized compaction by smaller organisms. Mechanical boring of hard substrata is an extreme form of excavation in which no compaction of burrow walls occurs and grains are abraded with rigid, hard structures. Chemical boring involves secretion to dissolve or soften generally carbonate substrata. Despite substantial differences in the mechanics of the media, similar burrowing behaviors are effective in mud and sand.

  20. Bias in the effective field theory of large scale structures

    SciTech Connect

    Senatore, Leonardo

    2015-11-05

    We study how to describe collapsed objects, such as galaxies, in the context of the Effective Field Theory of Large Scale Structures. The overdensity of galaxies at a given location and time is determined by the initial tidal tensor, velocity gradients and spatial derivatives of the regions of dark matter that, during the evolution of the universe, ended up at that given location. Similarly to what was recently done for dark matter, we show how this Lagrangian space description can be recovered by upgrading simpler Eulerian calculations. We describe the Eulerian theory. We show that it is perturbatively local in space, but non-local in time, and we explain the observational consequences of this fact. We give an argument for why to a certain degree of accuracy the theory can be considered as quasi time-local and explain what the operator structure is in this case. Furthermore, we describe renormalization of the bias coefficients so that, after this and after upgrading the Eulerian calculation to a Lagrangian one, the perturbative series for galaxies correlation functions results in a manifestly convergent expansion in powers of k/kNL and k/kM, where k is the wavenumber of interest, kNL is the wavenumber associated to the non-linear scale, and kM is the comoving wavenumber enclosing the mass of a galaxy.

  1. Bias in the effective field theory of large scale structures

    DOE PAGES

    Senatore, Leonardo

    2015-11-05

    We study how to describe collapsed objects, such as galaxies, in the context of the Effective Field Theory of Large Scale Structures. The overdensity of galaxies at a given location and time is determined by the initial tidal tensor, velocity gradients and spatial derivatives of the regions of dark matter that, during the evolution of the universe, ended up at that given location. Similarly to what was recently done for dark matter, we show how this Lagrangian space description can be recovered by upgrading simpler Eulerian calculations. We describe the Eulerian theory. We show that it is perturbatively local inmore » space, but non-local in time, and we explain the observational consequences of this fact. We give an argument for why to a certain degree of accuracy the theory can be considered as quasi time-local and explain what the operator structure is in this case. Furthermore, we describe renormalization of the bias coefficients so that, after this and after upgrading the Eulerian calculation to a Lagrangian one, the perturbative series for galaxies correlation functions results in a manifestly convergent expansion in powers of k/kNL and k/kM, where k is the wavenumber of interest, kNL is the wavenumber associated to the non-linear scale, and kM is the comoving wavenumber enclosing the mass of a galaxy.« less

  2. Improvements in Monte Carlo Simulation of Large Electron Fields

    SciTech Connect

    Faddegon, Bruce A.; Perl, Joseph; Asai, Makoto; /SLAC

    2007-11-28

    Two Monte Carlo systems, EGSnrc and Geant4, were used to calculate dose distributions in large electron fields used in radiotherapy. Source and geometry parameters were adjusted to match calculated results with measurement. Both codes were capable of accurately reproducing the measured dose distributions of the 6 electron beams available on the accelerator. Depth penetration was matched to 0.1 cm. Depth dose curves generally agreed to 2% in the build-up region, although there is an additional 2-3% experimental uncertainty in this region. Dose profiles matched to 2% at the depth of maximum dose in the central region of the beam, out to the point of the profile where the dose begins to fall rapidly. A 3%/3mm match was obtained outside the central region except for the 6 MeV beam, where dose differences reached 5%. The discrepancy observed in the bremsstrahlung tail in published results that used EGS4 is no longer evident. The different systems required different source energies, incident beam angles, thicknesses of the exit window and primary foils, and distance between the primary and secondary foil. These results underscore the requirement for an experimental benchmark of electron scatter for beam energies and foils relevant to radiotherapy.

  3. Bias in the effective field theory of large scale structures

    SciTech Connect

    Senatore, Leonardo

    2015-11-01

    We study how to describe collapsed objects, such as galaxies, in the context of the Effective Field Theory of Large Scale Structures. The overdensity of galaxies at a given location and time is determined by the initial tidal tensor, velocity gradients and spatial derivatives of the regions of dark matter that, during the evolution of the universe, ended up at that given location. Similarly to what was recently done for dark matter, we show how this Lagrangian space description can be recovered by upgrading simpler Eulerian calculations. We describe the Eulerian theory. We show that it is perturbatively local in space, but non-local in time, and we explain the observational consequences of this fact. We give an argument for why to a certain degree of accuracy the theory can be considered as quasi time-local and explain what the operator structure is in this case. We describe renormalization of the bias coefficients so that, after this and after upgrading the Eulerian calculation to a Lagrangian one, the perturbative series for galaxies correlation functions results in a manifestly convergent expansion in powers of k/k{sub NL} and k/k{sub M}, where k is the wavenumber of interest, k{sub NL} is the wavenumber associated to the non-linear scale, and k{sub M} is the comoving wavenumber enclosing the mass of a galaxy.

  4. SU-E-J-233: A Facility for Radiobiological Experiments in a Large Magnetic Field

    SciTech Connect

    Carlone, M; Heaton, R; Keller, H; Wouters, B; Jaffray, D

    2014-06-01

    Purpose: There is considerable interest in developing medical linear accelerators with integrated image guidance by MRI. Less work has been done on the fundamental biology of cell survival in the presence of a strong magnetic field. The purpose of this work is to describe an experimental system capable of measuring cell survival response in the types of MRI-linac systems currently under development. Methods: We have integrated a cobalt irradiator with a solenoid magnet. The solenoid magnet has inner diameter of 10 cm. To enable measurement of the biological effects as a function of depth, we are utilizing the sliced gel technique, in which cells are embedded and fixed within a gelatin matrix. Irradiated cells at defined positions (sub mm resolution) can subsequently be recovered and assessed for cell survival or other biological effects. Results: The magnetic field profile in the solenoid has a peak magnetic field 36 cm below the top edge of the magnet bore and can be placed at and SAD of 100 cm. At a solenoid current of 35 A, the peak magnetic field is 0.25 T. The dose rate of the cobalt irradiator is 16 cGy/min at 100 cm SAD. EBT3 film was used to demonstrate the system functionality. It was irradiated at 1 cm depth at 100 cm SSD with a 4×4 field to 1.5 Gy in a 0.25 T magnetic field. The dose profile was similar between this film and the control exposure without magnetic field. Conclusion: Integrating a cobalt irradiator with a high field magnet is demonstrated. The magnetic field at the cobalt defining head was minimal and did not interfere with the functioning of this unit. Cell survival experiments can be reproduced exactly in the presence or absence of a magnetic field since a resistive magnet is used.

  5. The persistence of large-scale blowouts in largely vegetated coastal dune fields

    NASA Astrophysics Data System (ADS)

    Delgado-Fernandez, Irene; Smyth, Thomas; Jackson, Derek; Davidson-Arnott, Robin; Smith, Alexander

    2016-04-01

    Coastal dunes move through natural phases of stability and instability during their evolution, displaying various temporal and spatial patterns across the dune field. Recent observations, however, have shown exceptionally rapid rates of stability through increased vegetative growth. This progressive vegetation colonisation and consequent loss of bare sand on coastal dune systems has been noted worldwide. Percentage reductions in bare sand of as much as 80% within just a few decades can been seen in examples from South Africa, Canada and Brazil as well as coastal dune sites across NW Europe. Despite these dramatic trends towards dune stabilisation, it is not uncommon to find particular examples of large-scale active blowouts and parabolic dunes within largely vegetated coastal dunes. While turbulence and airflow dynamics within features such as blowouts and other dune forms has been studied in detail within recent years, there is a lack of knowledge about what maintains dune mobility at these specific points in otherwise largely stabilized dune fields. This work explores the particular example of the 'Devil's Hole' blowout, Sefton Dunes, NW England. Approximately 300 m long by 100 m wide, its basin is below the water-table which leads to frequent flooding. Sefton Dunes in general have seen a dramatic loss of bare sand since the 1940s. However, and coinciding with this period of dune stabilisation, the 'Devil's Hole' has not only remained active but also grown in size at a rate of 4.5 m year-1 along its main axis. An exploration of factors controlling the maintenance of open bare sand areas at this particular location is examined using a variety of techniques including Computational Fluid Dynamics (CFD) airflow modelling and in situ empirical measurements of (short-term experiments) of wind turbulence and sand transport. Field measurements of wind parameters and transport processes were collected over a 2 week period during October 2015. Twenty three 3D ultrasonic

  6. Large-scale properties of the interplanetary magnetic field

    NASA Technical Reports Server (NTRS)

    Schatten, K. H.

    1972-01-01

    Early theoretical work of Parker is presented along with the observational evidence supporting his Archimedes spiral model. Variations present in the interplanetary magnetic field from the spiral angle are related to structures in the solar wind. The causes of these structures are found to be either nonuniform radial solar wind flow or the time evolution of the photospheric field. Coronal magnetic models are related to the connection between the solar magnetic field and the interplanetary magnetic field. Direct extension of the solar field-magnetic nozzle controversy is discussed along with the coronal magnetic models. Effects of active regions on the interplanetary magnetic field is discussed with particular reference to the evolution of interplanetary sectors. Interplanetary magnetic field magnitude variations are shown throughout the solar cycle. The percentage of time the field magnitude is greater than 10 gamma is shown to closely parallel sunspot number. The sun's polar field influence on the interplanetary field and alternative views of the magnetic field structure out of the ecliptic plane are presented. In addition, a variety of significantly different interplanetary field structures are discussed.

  7. Large area mode field photonic crystal fiber design

    NASA Astrophysics Data System (ADS)

    Guo, Shuqin; An, Wensheng; Wang, Kang; Zhu, Guangxin; Le, Zichun

    2005-11-01

    A novel design method about photonic crystal fiber (PCF) with large area model field (LAMF) is demonstrated. Different from ordinarily design that the core of PCF formed by missing one air holes in the center of section, many air holes distributed in heartland all together come into being the core region. Air holes are arranged regularly in core region and outer cladding regions according to different periodical character, respectively. The effective refractive index (n eff ) of core region should be higher than cladding region because of total internal reflection (TIR) requirement. In this paper, two kinds of typical scheme are offered to realize LAMF-PCF. First, Λ, the spacing of neighboring air holes in whole section is fixed, once the radius of air holes in the core region r c is smaller than the cladding air holes r cla, LAMF-PCF will be formed. The modal area only lessens a little as r c is reduced. Especially, optimal size of r c can nearly make MFA insensitive to wavelength. On the contrary, dispersion parameter of PCF will take place visible change along with r c reduced, and ultra-flattened dispersion character can be realized when r c is optimized. Another method of designing LAMF-PCF is keeping all air holes uniform in the whole section of PCF, but the space of neighboring air holes in the core region Λ c is longer than the cladding region Λ cla, so n eff of core region is higher than the cladding region and TIR can take place.

  8. Catalog of worldwide tidal bore occurrences and characteristics

    USGS Publications Warehouse

    Bartsch-Winkler, S.; Lynch, David K.

    1988-01-01

    Documentation of tidal bore phenomena occurring throughout the world aids in defining the typical geographical setting of tidal bores and enables prediction of their occurrence in remote areas. Tidal bores are naturally occurring, tidally generated, solitary, moving water waves up to 6 meters in height that form upstream in estuaries with semidiurnal or nearly semidiurnal tide ranges exceeding 4 meters. Estuarine settings that have tidal bores typically include meandering fluvial systems with shallow gradients. Bores are well defined, having amplitudes greater than wind- or turbulence-caused waves, and may be undular or breaking. Formation of a bore is dependent on depth and velocity of the incoming tide and river outflow. Bores may occur in series (in several channels) or in succession (marking each tidal pulse). Tidal bores propagate up tidal estuaries a greater distance than the width of the estuary and most occur within 100 kilometers upstream of the estuary mouth. Because they are dynamic, bores cause difficulties in some shipping ports and are targets for eradication. Tidal bores are known to occur, or to have occurred in the recent past, in at least 67 localities in 16 countries at all latitudes, including every continent except Antarctica. Parts of Argentina, Canada, Central America, China, Mozambique, Madagascar, Northern Europe, North and South Korea, the United Kingdom, and the U.S.S.R. probably have additional undiscovered or unreported tidal bores. In Turnagain Arm estuary in Alaska, bores cause an abrupt increase in salinity, suspended sediment, surface character, and bottom pressure, a decrease in illumination of the water column, and a change in water temperature. Tidal bores occurring in Turnagain Arm, Alaska, have the

  9. Challenges for D-brane large-field inflation with stabilizer fields

    NASA Astrophysics Data System (ADS)

    Landete, Aitor; Marchesano, Fernando; Wieck, Clemens

    2016-09-01

    We study possible string theory compactifications which, in the low-energy limit, describe chaotic inflation with a stabilizer field. We first analyze type IIA setups where the inflationary potential arises from a D6-brane wrapping an internal three-cycle, and where the stabilizer field is either an open-string or bulk Kähler modulus. We find that after integrating out the relevant closed-string moduli consistently, tachyonic directions arise during inflation which cannot be lifted. This is ultimately due to the shift symmetries of the type IIA Kähler potential at large compactification volume. This motivates us to search for stabilizer candidates in the complex structure sector of type IIB orientifolds, since these fields couple to D7-brane Wilson lines and their shift symmetries are generically broken away from the large complex structure limit. However, we find that in these setups the challenge is to obtain the necessary hierarchy between the inflationary and Kaluza-Klein scales.

  10. Environmental impact of a flocculant used to enhance solids transport during well bore clean-up operations

    SciTech Connect

    Yunus, M.N.M.; Procyk, A.D.; Malbrel, C.A.; Ling, K.L.C.

    1995-12-01

    This paper investigates particle flocculation as a mechanism to remove residual contaminants in well bores during completion operations. Laboratory tests and field trials were conducted demonstrating the ability of flocculating polymer sweeps to improve well bore cleaning efficiency. This process reduces the volume of fluid accumulated in the well bore that is discharged to the environment and minimizes the risk of formation damage by residuals left in the well bore. In addition, a comprehensive environmental impact study was performed on the flocculating polymers which included 72 hrs-EC50, 48 hrs-LC50, 10 day- LC50 tests on a variety of marine organisms, and bioaccumulation and biodegradability tests. In all cases, the flocculating polymers were shown to be environmentally safe at the recommended concentrations.

  11. A New Approach to Reduce Number of Split Fields in Large Field IMRT

    SciTech Connect

    Lee, Chen-Chiao; Wu, Andrew; Garg, Madhur; Mutyala, Subhakar; Kalnicki, Shalom; Sayed, Gary; Mah, Dennis

    2011-04-01

    Intensity-modulated radiation therapy (IMRT) has been applied for treatments of primary head with neck nodes, lung with supraclavicular nodes, and high-risk prostate cancer with pelvis wall nodes, all of which require large fields. However, the design of the Varian multileaf collimator requires fields >14 cm in width to be split into 2 or more carriage movements. With the split-field technique, both the number of monitor units (MUs) and total treatment time are significantly increased. Although many different approaches have been investigated to reduce the MU, including introducing new leaf segmentation algorithms, none have resulted in widespread success. In addition, for most clinics, writing such algorithms is not a feasible solution, particularly with commercial treatment planning systems. We introduce a new approach that can minimize the number of split fields and reduce the total MUs, thereby reducing treatment time. The technique is demonstrated on the Eclipse planning system V7.3, but could be generalized to any other system.

  12. A new approach to reduce number of split fields in large field IMRT.

    PubMed

    Lee, Chen-Chiao; Wu, Andrew; Garg, Madhur; Mutyala, Subhakar; Kalnicki, Shalom; Sayed, Gary; Mah, Dennis

    2011-01-01

    Intensity-modulated radiation therapy (IMRT) has been applied for treatments of primary head with neck nodes, lung with supraclavicular nodes, and high-risk prostate cancer with pelvis wall nodes, all of which require large fields. However, the design of the Varian multileaf collimator requires fields >14 cm in width to be split into 2 or more carriage movements. With the split-field technique, both the number of monitor units (MUs) and total treatment time are significantly increased. Although many different approaches have been investigated to reduce the MU, including introducing new leaf segmentation algorithms, none have resulted in widespread success. In addition, for most clinics, writing such algorithms is not a feasible solution, particularly with commercial treatment planning systems. We introduce a new approach that can minimize the number of split fields and reduce the total MUs, thereby reducing treatment time. The technique is demonstrated on the Eclipse planning system V7.3, but could be generalized to any other system.

  13. Transient magnetic field and temperature modeling in large magnet applications

    SciTech Connect

    Gurol, H.; Hardy, G.E.; Peck, S.D.; Leung, E. . Space Systems Div.)

    1989-07-01

    This paper discusses a coupled magnetic/thermal model developed to study heat and magnetic field diffusion in conducting materials subject to time-varying external fields. There are numerous applications, both military and commercial. These include: energy storage devices, pulsed power transformers, and electromagnetic launchers. The time scales of interest may range from a magnetic field pulse of a microsecond in an electromagnetic launcher, to hundreds of seconds in an energy storage magnet. The problem can be dominated by either the magnetic field or heat diffusion, depending on the temperature and the material properties of the conductor. In general, heat diffuses much more rapidly in high electrical conductivity materials of cryogenic temperatures. The magnetic field takes longer to diffuse, since screening currents can be rapidly set up which shield the interior of the material from further magnetic field penetration. Conversely, in high resistivity materials, the magnetic field diffuses much more rapidly. A coupled two-dimensional thermal/magnetic model has been developed. The results of this model, showing the time and spatial variation of the magnetic field and temperature, are discussed for the projectile of an electromagnetic launcher.

  14. Dosimetric impact of image artifact from a wide-bore CT scanner in radiotherapy treatment planning

    SciTech Connect

    Wu, Vincent; Podgorsak, Matthew B.; Tran, Tuan-Anh; Malhotra, Harish K.; Wang, Iris Z.

    2011-07-15

    Purpose: Traditional computed tomography (CT) units provide a maximum scan field-of-view (sFOV) diameter of 50 cm and a limited bore size, which cannot accommodate a large patient habitus or an extended simulation setup in radiation therapy (RT). Wide-bore CT scanners with increased bore size were developed to address these needs. Some scanners have the capacity to reconstruct the CT images at an extended FOV (eFOV), through data interpolation or extrapolation, using projection data acquired with a conventional sFOV. Objects that extend past the sFOV for eFOV reconstruction may generate image artifacts resulting from truncated projection data; this may distort CT numbers and structure contours in the region beyond the sFOV. The purpose of this study was to evaluate the dosimetric impact of image artifacts from eFOV reconstruction with a wide-bore CT scanner in radiotherapy (RT) treatment planning. Methods: Testing phantoms (i.e., a mini CT phantom with equivalent tissue inserts, a set of CT normal phantoms and anthropomorphic phantoms of the thorax and the pelvis) were used to evaluate eFOV artifacts. Reference baseline images of these phantoms were acquired with the phantom centrally positioned within the sFOV. For comparison, the phantoms were then shifted laterally and scanned partially outside the sFOV, but still within the eFOV. Treatment plans were generated for the thoracic and pelvic anthropomorphic phantoms utilizing the Eclipse treatment planning system (TPS) to study the potential effects of eFOV artifacts on dose calculations. All dose calculations of baseline and test treatment plans were carried out using the same MU. Results: Results show that both body contour and CT numbers are altered by image artifacts in eFOV reconstruction. CT number distortions of up to -356 HU for bone tissue and up to 323 HU for lung tissue were observed in the mini CT phantom. Results from the large body normal phantom, which is close to a clinical patient size, show

  15. True color tube bore inspection system

    NASA Astrophysics Data System (ADS)

    Pechersky, Martin J.; Harpring, Larry J.

    2000-03-01

    A True Color Tube Bore Inspection System (TCTBIS) has been developed to aid in the visual nondestructive examination of the inside surfaces of small bore stainless steel tubes. The instrument was developed to inspect for the presence of contaminants and oxidation on the inner surfaces of these 1.5 to 1.7 millimeter inside diameter tubes. Previously a parameter called the color factor, which can be calculated from the images collected by the TCTBIS, was found to be a good measure of the surface quality in these tubes. The color factor is a global number in the sense that it is calculated for the entire inspection region. Additional algorithms have also been developed to evaluate the tube based on surface inhomogeneities that are indicative of the presence of foreign matter, local chemical attack or other undesirable but localized conditions. These algorithms have been incorporated into an up-to-date apparatus which is described in detail. We have also investigated the feasibility of using artificial intelligence techniques to aid in the interpretation of these defects. Promising results were obtained with a feed forward, back propagation artificial neural network.

  16. Observational and Modeling Study of Mesopheric Bores

    NASA Astrophysics Data System (ADS)

    Loughmiller, P.; Kelley, M.; Hickey, M.

    In our studies of the dynamics of the upper atmosphere, some of the most intriguing mesospheric phenomena we observe high over the Hawaiian night skies are internal bores. These events affecting chemiluminescence are documented in monochromatic airglow images taken by high performance all-sky CCD imaging systems operating at the Maui Space Surveillance Site on top of Haleakala Crater. Data is collected as part of the ongoing, collaborative Maui - Mesosphere and Lower Thermosphere (MALT) campaign, jointly sponsored by the National Science Foundation and the Air Force Office of Scientific Research. Bolstered by the Maui-MALT dataset, several theories now exist for mesospheric bores, agreeing in principle that they are likely nonlinear structures spawned by gravity waves and propagating within ducted waveguide regions, such as thermal inversion layers. A new investigation will model optical emissions using a robust, time-dependent, chemical dynamics model to explore the airglow response to ducted gravity waves and, in turn, the geographical and vertical coupling relationships which may exist.

  17. Large slow roll parameters in single field inflation

    SciTech Connect

    Cook, Jessica L.; Krauss, Lawrence M. E-mail: krauss@asu.edu

    2016-03-01

    We initially consider two simple situations where inflationary slow roll parameters are large and modes no longer freeze out shortly after exiting the horizon, treating both cases analytically. By modes, we refer to the comoving curvature perturbation R. We then consider applications to transient phases where the slow roll parameters can become large, especially in the context of the common 'fast-roll' inflation frequently used as a mechanism to explain the anomalously low scalar power at low l in the CMB. These transient cases we treat numerically. We find when ε, the first slow roll parameter, and only ε is large, modes decay outside the horizon, and when δ, the second slow roll parameter, is large, modes grow outside the horizon. When multiple slow roll parameters are large the behavior in general is more complicated, but we nevertheless show in the 'fast-roll' inflation case, modes grow outside the horizon.

  18. Deep bore hole instrumentation along San Francisco Bay Bridges

    SciTech Connect

    Bakun, W.; Bowman, J.; Clymer, R.; Foxall, W.; Hipley, P.; Hollfelder, J.; Hutchings, L.; Jarpe, S.; Kasameyer, P.; McEvilly, T.; Mualchin, L.; Palmer, M.

    1998-10-01

    The Bay Bridges down hole network consists of sensors in bore holes that are drilled 100 ft. into bedrock around and in the San Francisco Bay. Between 2 and 8 instruments have been spaced along the Dumbarton, San Mateo, Bay, and San Rafael bridges. The instruments will provide multiple use data that is important to geotechnical, structural engineering, and seismological studies. The holes are between 100 and 1000 ft deep and were drilled by Caltrans. There are twenty- one sensor packages at fifteen sites. Extensive financial support is being contributed by Caltrans, UCB, LBL, LLNL-LDRD, U.C. Campus/Laboratory Collaboration (CLC) program, and USGS. The down hole instrument package contains a three component HS-1 seismometer and three orthogonal Wilcox 73 1 accelerometers, and is capable of recording a micro g from local M = 1.0 earthquakes to 0.5 g strong ground motion form large Bay Area earthquakes.

  19. Large-scale field testing on flexible shallow landslide barriers

    NASA Astrophysics Data System (ADS)

    Bugnion, Louis; Volkwein, Axel; Wendeler, Corinna; Roth, Andrea

    2010-05-01

    Open shallow landslides occur regularly in a wide range of natural terrains. Generally, they are difficult to predict and result in damages to properties and disruption of transportation systems. In order to improve the knowledge about the physical process itself and to develop new protection measures, large-scale field experiments were conducted in Veltheim, Switzerland. Material was released down a 30° inclined test slope into a flexible barrier. The flow as well as the impact into the barrier was monitored using various measurement techniques. Laser devices recording flow heights, a special force plate measuring normal and shear basal forces as well as load cells for impact pressures were installed along the test slope. In addition, load cells were built in the support and retaining cables of the barrier to provide data for detailed back-calculation of load distribution during impact. For the last test series an additional guiding wall in flow direction on both sides of the barrier was installed to achieve higher impact pressures in the middle of the barrier. With these guiding walls the flow is not able to spread out before hitting the barrier. A special constructed release mechanism simulating the sudden failure of the slope was designed such that about 50 m3 of mixed earth and gravel saturated with water can be released in an instant. Analysis of cable forces combined with impact pressures and velocity measurements during a test series allow us now to develop a load model for the barrier design. First numerical simulations with the software tool FARO, originally developed for rockfall barriers and afterwards calibrated for debris flow impacts, lead already to structural improvements on barrier design. Decisive for the barrier design is the first dynamic impact pressure depending on the flow velocity and afterwards the hydrostatic pressure of the complete retained material behind the barrier. Therefore volume estimation of open shallow landslides by assessing

  20. Large Scale High-Latitude Ionospheric Electrodynamic Fields and Currents

    NASA Astrophysics Data System (ADS)

    Lu, Gang

    2017-03-01

    This paper provides an overview as well as the application of the Assimilative Mapping of Ionospheric Electrodynamics (AMIE) procedure. AMIE synthesizes observations from various ground-based and space-born instruments to derive global patterns of ionospheric conductance, electric fields, ionospheric equivalent current, horizontal currents, field-aligned currents, and other related electrodynamic fields simultaneously. Examples are presented to illustrate the effects of the different data inputs on the AMIE outputs. The AMIE patterns derived from ground magnetometer data are generally similar to those derived from satellite magnetometer data. But ground magnetometer data yield a cross-polar potential drop that is about 15-45 % smaller than that derived from satellite magnetometer data. Ground magnetometers also grossly underestimate the magnetic perturbations in space when compared with the in situ satellite magnetometer data. However, when satellite magnetometer data are employed, AMIE is able to replicate the observed magnetic perturbations along the satellite tracks with a mean root-mean-square (RMS) error of 17-21 %. In addition to derive snapshots of ionospheric electrodynamic fields, the utility of AMIE can be easily expanded to obtain the average distributions of these fields along with their associated variability. Such information should be valuable to the analysis and interpretation of the Swarm observations.

  1. Advanced wide-field broad-passband refracting field correctors for large telescopes

    NASA Technical Reports Server (NTRS)

    Epps, H. W.; Angel, J. R. P.; Anderson, E.

    1984-01-01

    Design objectives, constraints, and optical data are presented for specific corrector designs under consideration for several large telescope projects. These include a preliminary 30-arcmin prime focus (f/2.0) refracting field corrector system for the University of California Ten-Meter Telescope (UC TMT); a compact 40-arcmin internal Cassegrain (f/1.75 hyperbola to f/5.0) broad-passband (3300 A to 1.0 micron) corrector suitable for imaging and multi-object spectroscopy at the UC TMT; three 60-arcmin Cassegrain correctors for 300-inch f/1.8 and f/2.0 parabolic primary mirrors suitable for a Fifteen-Meter NNTT/MMT; and a 300-inch 40-arcmin external Cassegrain (f/1.0 parabola to f/4.0) broad-passband (3300 A to 1.0 micron) corrector with ADC.

  2. Affirmative Action in Nine Large Companies: A Field Study.

    ERIC Educational Resources Information Center

    Vernon-Gerstenfeld, Susan; Burke, Edmund

    1985-01-01

    The authors describe the findings of a field study of affirmative action programs in companies in a variety of industries. The distinction between equal employment opportunity and affirmative action is addressed. Methods used to train managers in implementing affirmative action are examined. Also explores employee development, community…

  3. The magnetic field of the Large Magellanic Cloud revealed through Faraday rotation.

    PubMed

    Gaensler, B M; Haverkorn, M; Staveley-Smith, L; Dickey, J M; McClure-Griffiths, N M; Dickel, J R; Wolleben, M

    2005-03-11

    We have measured the Faraday rotation toward a large sample of polarized radio sources behind the Large Magellanic Cloud (LMC) to determine the structure of this galaxy's magnetic field. The magnetic field of the LMC consists of a coherent axisymmetric spiral of field strength approximately 1 microgauss. Strong fluctuations in the magnetic field are also seen on small (<0.5 parsec) and large (approximately 100 parsecs) scales. The large bursts of recent star formation and supernova activity in the LMC argue against standard dynamo theory, adding to the growing evidence for rapid field amplification in galaxies.

  4. Large-area Overhead Manipulator for Access of Fields

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Multi-axis, cable-driven manipulators have evolved over many years providing large area suspended platform access, programmability, relatively rigid and flexibly-positioned platform control and full six degree of freedom (DOF) manipulation of sensors and tools. We describe innovations for a new six...

  5. Large filters for wide-field survey telescope LSST

    NASA Astrophysics Data System (ADS)

    Morgado, Nazario; Pinard, Laurent; Sassolas, Benoit; Flaminio, Raffaele; Forest, Daniéle; Lagrange, Bernard; Michel, Christophe; Antilogus, Pierre

    2012-09-01

    The LSST design foresees the use of six wide-band large optical filters that can alternatively be moved in front of the CCD camera. Each of the six filters has a different band-pass covering all the wavelengths from 300 nm to 1200 nm. The way to achieve this is to coat an optimized optical thin films stack on a filter substrate. Each filter requires a specific design using specific appropriate materials. The main characteristics of these filters, that constitute a real technological challenge, are: their relatively large size - their radii of curvature (about 5.6 m) that represent a sagitta of 12,5 mm that increases the uniformity complexity, the large rejection band requirements with transmission lower than 0.01 % out of the band and a transmission of 95 % over the band-pass. This paper proposes to show the problematic and the results obtained at LMA (Laboratoire des Matériaux Avancés-FRANCE) to the purpose of realizing these filters using the IBS (Ion Beam Sputtering) deposition technique. The results obtained with High-Pass/Low-Pass structures will be presented. Experimental results will be shown concerning the R-band filter (552-691 nm). An overview of the work to be done to realize transmittance map over large filters will be given.

  6. Virtually distortion-free imaging system for large field, high resolution lithography

    DOEpatents

    Hawryluk, Andrew M.; Ceglio, Natale M.

    1993-01-01

    Virtually distortion free large field high resolution imaging is performed using an imaging system which contains large field distortion or field curvature. A reticle is imaged in one direction through the optical system to form an encoded mask. The encoded mask is then imaged back through the imaging system onto a wafer positioned at the reticle position.

  7. Virtually distortion-free imaging system for large field, high resolution lithography

    DOEpatents

    Hawryluk, A.M.; Ceglio, N.M.

    1993-01-05

    Virtually distortion free large field high resolution imaging is performed using an imaging system which contains large field distortion or field curvature. A reticle is imaged in one direction through the optical system to form an encoded mask. The encoded mask is then imaged back through the imaging system onto a wafer positioned at the reticle position.

  8. Lower hybrid accessibility in a large, hot reversed field pinch

    SciTech Connect

    Dziubek, R.A.; Harvey, R.W.; Hokin, S.A.; Uchimoto, E.

    1995-11-01

    Accessibility and damping of the slow wave in a reversed field pinch (RFP) plasma is investigated theoretically, using projected Reversed Field Experiment (RFX) plasma parameters. By numerically solving the hot plasma dispersion relation, regions of propagation are found and the possibility of mode conversion is analyzed. If the parallel index of refraction of the wave is chosen judiciously at the edge of the plasma, the slow wave is accessible to a target region located just inside the reversal surface without mode conversion. Landau damping is also optimized in this region. A representative fast electron population is then added in order to determine its effect on accessibility and damping. The presence of these electrons, whose parameters were estimated by extrapolation of Madison Symmetric Torus (MST) data, does not affect the accessibility of the wave. However, the initial phase velocity of the wave needs to be increased somewhat in order to maintain optimal damping in the target zone.

  9. Hamiltonian identification in presence of large control field perturbations

    NASA Astrophysics Data System (ADS)

    Fu, Ying; Rabitz, Herschel; Turinici, Gabriel

    2016-12-01

    Quantum system inversion concerns learning the characteristics of the underlying Hamiltonian by measuring suitable observables from the responses of the system’s interaction with members of a set of applied fields. Various aspects of inversion have been confirmed in theoretical, numerical and experimental works. Nevertheless, the presence of noise arising from the applied fields may contaminate the quality of the results. In this circumstance, the observables satisfy probability distributions, but often the noise statistics are unknown. Based on a proposed theoretical framework, we present a procedure to recover both the unknown parts of the Hamiltonian and the unknown noise distribution. The procedure is implemented numerically and seen to perform well for illustrative Gaussian, exponential and bi-modal noise distributions.

  10. Laser Plasma Particle Accelerators: Large Fields for Smaller Facility Sources

    SciTech Connect

    Geddes, Cameron G.R.; Cormier-Michel, Estelle; Esarey, Eric H.; Schroeder, Carl B.; Vay, Jean-Luc; Leemans, Wim P.; Bruhwiler, David L.; Cary, John R.; Cowan, Ben; Durant, Marc; Hamill, Paul; Messmer, Peter; Mullowney, Paul; Nieter, Chet; Paul, Kevin; Shasharina, Svetlana; Veitzer, Seth; Weber, Gunther; Rubel, Oliver; Ushizima, Daniela; Bethel, Wes; Wu, John

    2009-03-20

    Compared to conventional particle accelerators, plasmas can sustain accelerating fields that are thousands of times higher. To exploit this ability, massively parallel SciDAC particle simulations provide physical insight into the development of next-generation accelerators that use laser-driven plasma waves. These plasma-based accelerators offer a path to more compact, ultra-fast particle and radiation sources for probing the subatomic world, for studying new materials and new technologies, and for medical applications.

  11. Formulating entompathogens for control of boring beetles in avocado orchards

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A foam formulation of Beauveria bassiana was adapted to control boring beetles in avocado orchards. The two geographically independent avocado growing areas in the United States are threatened by emerging diseases vectored by boring beetles. In the California growing region, Fusarium dieback is vect...

  12. A purely reflective large wide-field telescope

    NASA Astrophysics Data System (ADS)

    Terebizh, V. Yu.

    2008-06-01

    Two versions of a fast, purely reflective Paul-Baker-type telescope are discussed, each with an 8.4-m aperture, 3° diameter flat field and f/1.25 focal ratio. The first version is based on a common, even asphere type of surface with zero conic constant. The primary and tertiary mirrors are 6th order aspheres, while the secondary mirror is an 8th order asphere (referred to here for brevity, as the 6/8/6 configuration). The D 80 diameter of a star image varies from 0″.18 on the optical axis up to 0″.27 at the edge of the field (9.3-13.5 μm). The second version of the telescope is based on a polysag surface type, which uses a polynomial expansion in the sag z, r^2 = 2R_0 z - left( {1 + b} right)z^2 + a_3 z^3 + a_4 z^3 + a_4 z^4 + ldots + a_N z^N instead of the common form of aspheric surface. This approach results in somewhat better images, with D 80 ranging from 0″.16 to 0″.23, using a lower-order 3/4/3 combination of powers for the mirror surfaces. An additional example with 3.5-m aperture, 3°.5 diameter flat field, and f/1.25 focal ratio featuring near-diffraction-limited image quality is also presented.

  13. ASSEMBLY AND TEST OF A 120 MM BORE 15 T NB3SN QUADRUPOLE FOR THE LHC UPGRADE

    SciTech Connect

    Felice, H.; Caspi, S.; Cheng, D.; Dietderich, D.; Ferracin, P.; Hafalia, R.; Joseph, J.; Lizarazo, J.; Sabbi, G. L.; Wang, X.; Anerella, M.; Ghosh, A. K.; Schmalzle, J.; Wanderer, P.; Ambrosio, G.; Bossert, R.; Zlobin, A. V.

    2010-05-23

    In support of the Large Hadron Collider (LHC) luminosity upgrade, the US LHC Accelerator Research Program (LARP) has been developing a 1-meter long, 120 mm bore Nb{sub 3}Sn IR quadrupole magnet (HQ). With a design short sample gradient of 219 T/m at 1.9 K and a peak field approaching 15 T, one of the main challenges of this magnet is to provide appropriate mechanical support to the coils. Compared to the previous LARP Technology Quadrupole and Long Quadrupole magnets, the purpose of HQ is also to demonstrate accelerator quality features such as alignment and cooling. So far, 8 HQ coils have been fabricated and 4 of them have been assembled and tested in HQ01a. This paper presents the mechanical assembly and test results of HQ01a.

  14. Low Field, Large Magnetoresistance in Nonmagnetic Organic Semiconductors

    NASA Astrophysics Data System (ADS)

    Bergeson, Jeremy D.

    2007-03-01

    Transport in various thin-film organic semiconductors has been shown to have an anomalously high sensitivity to low magnetic fields at room temperature (RT). Early experiments on polydiacetylene single crystals and poly(phenylenevinylene)s revealed increases in photoconductivity of a few percent at RT. Further magnetotransport studies showed larger effects in π-conjugated backbone polymers and small molecules. We report magnetoresistance (MR) for semiconducting oligomer and nonconjugated polymer materials in addition to small molecule and conjugated backbone polymer materials. For example, films of the light emitters poly(N-vinylcarbazole) and Alq3 each have an MR response greater than 5% at an unusually low magnetic field of 100 Oe (μBH ˜0.0006 meV) at an unusually high temperature of 300 K (kBT ˜26 meV). Increasing the spin-orbit coupling in Alq3 films by doping with the phosphorescent sensitizers Ir(ppy)3 or PtOEP strongly suppresses the MR signal. MR in thin films of the oligomer α-sexithiophene can be negative, similar to the behavior of other organic semiconductors, or positive depending on the temperature, layer thickness, or applied voltage. We have developed a model, termed Magnetoresistance by the Interconversion of Singlets and Triplets (MIST), accounting for this anomalous MR. At zero field, the singlet and triplet e-h pair states are degenerate and the states can readily interconvert due to hyperfine interaction. Finite magnetic fields lift triplet degeneracy which affects the hyperfine interconversion of e-h pairs between singlet and triplet states. By changing the carrier recombination the MIST mechanism gives rise to a space-charge-limited current that depends on magnetic field, producing MR. E.L. Frankevich, et al., Mol. Cryst. Liq. Cryst.175, 41 (1989); E.L. Frankevich, et al., Phys. Rev. B 46, 9320 (1992). O. Mermer, et al., Phys. Rev. B 72, 205202 (2005). V.N. Prigodin, et al., Synth. Met.156, 757 (2006).

  15. Oil well bore hole surveying by kinematic navigation

    SciTech Connect

    Egli, W.H.; Vallot, L.C.

    1988-08-30

    This patent describes a bore hole survey apparatus, comprising: an instrumentation pod adapted for travel down a bore hole to be surveyed; the pod including a rate gyroscope for sensing rotation of the pod substantially about its longitudinal axis along which it travels in the bore hole; the pod including accelerometer means for sensing the Earth's gravity vector with respect to a frame of reference of the pod; means for lowering the pod in a bore hole and for measuring increments of the lowering; and computational means connected for receiving signals from the rate gyroscope, the accelerometers and the lowering means, and for calculating therefrom the updated attitude and position of the pod as it is lowered into the bore hole, the computational means being programmed with an algorithm which calculates the updated pod location.

  16. Camera relative orientation in large field of view

    NASA Astrophysics Data System (ADS)

    Wang, Jun; Dong, Mingli; Li, Wei; Sun, Peng

    2016-01-01

    A new relative orientation w local parameter optimization method of the essential matrix for the large scale close range photogrammetry is presented in this paper to improve the accuracy and stability of the measurement system. For the matched images, according to the closed-loop polynomial algorithm, the essential matrix is initialized, and an iterative algorithm based on local parameter optimization is proposed. Then the relative exterior orientation parameters are solved from the essential matrix, and only one correct solution is determined by the Cheirality constraints. The orientation experiment of the expandable truss microwave antenna profile measurement is carried out to verify the accuracy and reliability of the new method. Compared with the traditional methods, this new method has minimum projection error and the least iterations, and it will play a key role in the performance improvement of the whole system.

  17. Large-Scale Hybrid Dynamic Simulation Employing Field Measurements

    SciTech Connect

    Huang, Zhenyu; Guttromson, Ross T.; Hauer, John F.

    2004-06-30

    Simulation and measurements are two primary ways for power engineers to gain understanding of system behaviors and thus accomplish tasks in system planning and operation. Many well-developed simulation tools are available in today's market. On the other hand, large amount of measured data can be obtained from traditional SCADA systems and currently fast growing phasor networks. However, simulation and measurement are still two separate worlds. There is a need to combine the advantages of simulation and measurements. In view of this, this paper proposes the concept of hybrid dynamic simulation which opens up traditional simulation by providing entries for measurements. A method is presented to implement hybrid simulation with PSLF/PSDS. Test studies show the validity of the proposed hybrid simulation method. Applications of such hybrid simulation include system event playback, model validation, and software validation.

  18. Single-field consistency relations of large scale structure

    SciTech Connect

    Creminelli, Paolo; Noreña, Jorge; Simonović, Marko; Vernizzi, Filippo E-mail: jorge.norena@icc.ub.edu E-mail: filippo.vernizzi@cea.fr

    2013-12-01

    We derive consistency relations for the late universe (CDM and ΛCDM): relations between an n-point function of the density contrast δ and an (n+1)-point function in the limit in which one of the (n+1) momenta becomes much smaller than the others. These are based on the observation that a long mode, in single-field models of inflation, reduces to a diffeomorphism since its freezing during inflation all the way until the late universe, even when the long mode is inside the horizon (but out of the sound horizon). These results are derived in Newtonian gauge, at first and second order in the small momentum q of the long mode and they are valid non-perturbatively in the short-scale δ. In the non-relativistic limit our results match with [1]. These relations are a consequence of diffeomorphism invariance; they are not satisfied in the presence of extra degrees of freedom during inflation or violation of the Equivalence Principle (extra forces) in the late universe.

  19. Effect of centrifugal forces on dimensional error of bored shapes

    NASA Astrophysics Data System (ADS)

    Arsuaga, M.; de Lacalle, L. N. López; Lobato, R.; Urbikain, G.; Campa, F.

    2012-04-01

    Boring operations of deep holes with a slender boring bar are often hindered by the precision because of their low static stiffness and high deformations. Because of that, it is not possible to remove much larger depths of cuts than the nose radius of the tool, unlike the case of turning and face milling operations, and consequently, the relationship between the cutting force distribution, tool geometry, feed rate and depth of cut becomes non-linear and complex. This problem gets worse when working with a rotating boring head where apart from the cutting forces and the variation of the inclination angle because of shape boring, the bar and head are affected by de centrifugal forces. The centrifugal forces, and therefore the centrifugal deflection, will vary as a function of the rotating speed, boring bar mass distribution and variable radial position of the bar in shape boring. Taking in to account all this effects, a load and deformation model was created. This model has been experimentally validated to use as a corrector factor of the radial position of the U axis in the boring head.

  20. Large-scale Cyclic Features of Solar Magnetic Field

    NASA Astrophysics Data System (ADS)

    Song, W.; Wang, J.

    It is well accepted that the solar cycle originates from a magnetohydrodynamics dynamo deep inside the Sun Many dynamo models have long been proposed based on a lot of observational constraints In this paper using 342 NSO Kitt Peak synoptic charts we study the large-scale solar cycle features of photospheric magnetic flux to set further constraints According to the flux behaviors we categorize each hemisphere into four typical latitudinal zones the polar region the high latitude region the activity belt and the low latitude region 1 We find the mean latitudes of the boundaries of polar regions to be near 55 35° during solar minimums and 67 61° during solar maximums 2 There is an unipolar poleward magnetic flux found in the high latitude region during solar maximums 3 For the activity belt the flux peak time or the main phase of solar cycle are steady and has a period near 11 years From the higher latitudinal strips to the lower ones the total positive or negative magnetic flux accumulates with a speed of 2 48 times10 20 Mx deg Moreover we find that the latitude migration of magnetic flux which represents the Sp o rer law starts in this belt and can be written in a formula like phi 29 02-3 150t 0 1123t 2 4 The flux peak time of the low latitude region shifts forward with an average speed of 32 2 day deg From the higher latitudinal strips to the lower ones the total magnetic flux dissipates with a speed of 3 63 times10 20 Mx deg General speaking dynamo theories are developed for

  1. The large-scale magnetic field in the solar wind. [interplanetary magnetic fields/solar activity effects

    NASA Technical Reports Server (NTRS)

    Burlaga, L. F.; Ness, N. F.

    1975-01-01

    A large-scale, three dimensional magnetic field in the interplanetary medium with an expected classical spiral pattern to zeroth order is discussed. Systematic and random deviations which are expected are treated. The sector structure which should be evident at high latitudes is examined. Interplanetary streams are discussed as determining the patterns of magnetic field intensity. It was proposed that the large-scale spiral field can induce a meridional flow which might alter the field geometry somewhat. The nonuniformities caused by streams will probably significantly influence the motion of solar and galactic particles. It was concluded that knowledge of the 3-dimensional field and its dynamical effects can be obtained by in situ measurements by a probe which goes over the sun's poles. Diagrams of the magnetic fields are given.

  2. Large scale 3D geometry of deformation structures in the Aar massif and overlying Helvetic nappes (Central Alps, Switzerland) - A combined remote sensing and field work approach

    NASA Astrophysics Data System (ADS)

    Baumberger, R.; Wehrens, Ph.; Herwegh, M.

    2012-04-01

    Allowing deep insight into the formation history of a rock complex, shear zones, faults and joint systems represent important sources of geological information. The granitic rocks of the Haslital valley (Switzerland) show very good outcrop conditions to study these mechanical anisotropies. Furthermore, they permit a quantitative characterisation of the above-mentioned deformation structures on the large-scale, in terms of their 3D orientation, 3D spatial distribution, kinematics and evolution in 3D. A key problem while developing valid geological 3D models is the three-dimensional spatial distribution of geological structures, particularly with increasing distance from the surface. That is especially true in regions, where only little or even no "hard" underground data (e.g. bore holes, tunnel mappings and seismics) is available. In the study area, many subsurface data are available (e.g. cross sections, tunnel and pipeline mappings, bore holes etc.). Therefore, two methods dealing with the problems mentioned are developed: (1) A data acquisition, processing and visualisation method, (2) A methodology to improve the reliability of 3D models regarding the spatial trend of geological structures with increasing depth: 1) Using aerial photographs and a high-resolution digital elevation model, a GIS-based remote-sensing structural map of large-scale structural elements (shear zones, faults) of the study area was elaborated. Based on that lineament map, (i) a shear zone map was derived and (ii) a geostatistical analysis was applied to identify sub regions applicable for serving as field areas to test the methodology presented above. During fieldwork, the shear zone map was evaluated by verifying the occurrence and spatial distribution of the structures designated by remote sensing. Additionally, the geometry of the structures (e.g. 3D orientation, width, kinematics) was characterised and parameterised accordingly. These tasks were partially done using a GPS based Slate

  3. Large-scale dynamo growth rates from numerical simulations and implications for mean-field theories.

    PubMed

    Park, Kiwan; Blackman, Eric G; Subramanian, Kandaswamy

    2013-05-01

    Understanding large-scale magnetic field growth in turbulent plasmas in the magnetohydrodynamic limit is a goal of magnetic dynamo theory. In particular, assessing how well large-scale helical field growth and saturation in simulations match those predicted by existing theories is important for progress. Using numerical simulations of isotropically forced turbulence without large-scale shear with its implications, we focus on several additional aspects of this comparison: (1) Leading mean-field dynamo theories which break the field into large and small scales predict that large-scale helical field growth rates are determined by the difference between kinetic helicity and current helicity with no dependence on the nonhelical energy in small-scale magnetic fields. Our simulations show that the growth rate of the large-scale field from fully helical forcing is indeed unaffected by the presence or absence of small-scale magnetic fields amplified in a precursor nonhelical dynamo. However, because the precursor nonhelical dynamo in our simulations produced fields that were strongly subequipartition with respect to the kinetic energy, we cannot yet rule out the potential influence of stronger nonhelical small-scale fields. (2) We have identified two features in our simulations which cannot be explained by the most minimalist versions of two-scale mean-field theory: (i) fully helical small-scale forcing produces significant nonhelical large-scale magnetic energy and (ii) the saturation of the large-scale field growth is time delayed with respect to what minimalist theory predicts. We comment on desirable generalizations to the theory in this context and future desired work.

  4. Recovering the full velocity and density fields from large-scale redshift-distance samples

    NASA Technical Reports Server (NTRS)

    Bertschinger, Edmund; Dekel, Avishai

    1989-01-01

    A new method for extracting the large-scale three-dimensional velocity and mass density fields from measurements of the radial peculiar velocities is presented. Galaxies are assumed to trace the velocity field rather than the mass. The key assumption made is that the Lagrangian velocity field has negligible vorticity, as might be expected from perturbations that grew by gravitational instability. By applying the method to cosmological N-body simulations, it is demonstrated that it accurately reconstructs the velocity field. This technique promises a direct determination of the mass density field and the initial conditions for the formation of large-scale structure from galaxy peculiar velocity surveys.

  5. BORED AND ASSEMBLED GATE VALVES RECEIVING PROTECTIVE COATING IN THE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    BORED AND ASSEMBLED GATE VALVES RECEIVING PROTECTIVE COATING IN THE VALVE PAINT BOOTH OF THE VALVE ASSEMBLY BUILDING. - Stockham Pipe & Fittings Company, Valve Assembly Building, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  6. 9. VIEW OF WHEEL RACK FOR BORING MILL. Fork loading ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. VIEW OF WHEEL RACK FOR BORING MILL. Fork loading crane, manufactured by Cleveland Tramrail, 2-1/2 ton capacity. - Juniata Shops, Erecting Shop & Machine Shop, East of Fourth Avenue, between Fourth & Fifth Streets, Altoona, Blair County, PA

  7. 8. VIEW OF WHEEL RACK FOR BORING MILL. Fork loading ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. VIEW OF WHEEL RACK FOR BORING MILL. Fork loading crane, manufactured by Cleveland Tramrail, 2-1/2 ton capacity. - Juniata Shops, Erecting Shop & Machine Shop, East of Fourth Avenue, between Fourth & Fifth Streets, Altoona, Blair County, PA

  8. Low frequency magnetic field suppression in an atomic spin co-magnetometer with a large electron magnetic field

    NASA Astrophysics Data System (ADS)

    Fang, Jiancheng; Chen, Yao; Zou, Sheng; Liu, Xuejing; Hu, Zhaohui; Quan, Wei; Yuan, Heng; Ding, Ming

    2016-03-01

    In a K-Rb-21Ne co-magnetometer, the Rb electron magnetic field which is experienced by the nuclear spin is about 100 times larger than that of the K in a K-3He co-magnetometer. The large electron magnetic field which is neglected in the K-3He co-magnetometer coupled Bloch equations model is considered here in the K-Rb-21Ne co-magnetometer to study the low frequency magnetic field suppression effect. Theoretical analysis and experimental results shows that in the K-Rb-21Ne spin co-magnetometer, not only the nuclear spin but also the large electron spin magnetic field compensate the external magnetic field noise. By comparison, only the 3He nuclear spins mainly compensate the external magnetic field noise in a K-3He co-magnetometer. With this study, in addition to just increasing the magnetic field of the nuclear spins, we can suppress the magnetic field noise by increasing the density of the electron spin. We also studied how the magnetic field suppression effect relates to the scale factor of the K-Rb-21Ne co-magnetometer and we compared the scale factor with that of the K-3He co-magnetometer. Lastly, we show the sensitivity of our co-magnetometer. The magnetic field noise, the air density fluctuation noise and pumping power optimization are studied to improve the sensitivity of the co-magnetometer.

  9. Rectangular tunnel boring machine and method

    SciTech Connect

    Snyder, L.L.

    1984-12-04

    A machine for boring a tunnel having an end face wall, a roof wall, a bottom wall, and opposite side walls. The machine comprises a rotatable cutting wheel means having an annular peripheral wall supporting a plurality of cutting devices and a generally convex-shaped upper wall supporting a plurality of cutting devices. The cutting wheel means is rotatable about an axis of rotation which is inclined in a forward direction relative to a plane perpendicular to the longitudinal axis of the tunnel for simultaneously cutting the tunnel face along two intersecting surfaces defined by the cutting devices on the annular peripheral wall and the cutting devices on the convex-shape upper wall. Support shoe means are mounted beneath the cutting wheel means for movably supporting the cutting wheel means on the tunnel floor. Drive motor means are mounted on the support shoe means and are operatively associated with the cutting wheel means for causing rotation of the cutting wheel means relative to the tunnel face and the support shoe means. Thrust means are connected to the support shoe means for advancing the cutting wheel means and the support shoe means toward the tunnel face. Gripping means are associated with the thrust means for gripping engagement with the opposite tunnel side walls to prevent axial rearward movement as the cutting wheel means and the support shoe means are advanced toward the tunnel face. Vertical and horizontal steering means for changing the direction of advance of the machine are described. Paddle means and conveyor means for removing rock cuttings from the end face of the tunnel are disclosed. Shield means for shielding workers from dust and debris and for containing the cuttings are also described.

  10. Generation of large-scale magnetic fields by small-scale dynamo in shear flows

    DOE PAGES

    Squire, J.; Bhattacharjee, A.

    2015-10-20

    We propose a new mechanism for a turbulent mean-field dynamo in which the magnetic fluctuations resulting from a small-scale dynamo drive the generation of large-scale magnetic fields. This is in stark contrast to the common idea that small-scale magnetic fields should be harmful to large-scale dynamo action. These dynamos occur in the presence of a large-scale velocity shear and do not require net helicity, resulting from off-diagonal components of the turbulent resistivity tensor as the magnetic analogue of the "shear-current" effect. Furthermore, given the inevitable existence of nonhelical small-scale magnetic fields in turbulent plasmas, as well as the generic naturemore » of velocity shear, the suggested mechanism may help explain the generation of large-scale magnetic fields across a wide range of astrophysical objects.« less

  11. Generation of large-scale magnetic fields by small-scale dynamo in shear flows

    SciTech Connect

    Squire, J.; Bhattacharjee, A.

    2015-10-20

    We propose a new mechanism for a turbulent mean-field dynamo in which the magnetic fluctuations resulting from a small-scale dynamo drive the generation of large-scale magnetic fields. This is in stark contrast to the common idea that small-scale magnetic fields should be harmful to large-scale dynamo action. These dynamos occur in the presence of a large-scale velocity shear and do not require net helicity, resulting from off-diagonal components of the turbulent resistivity tensor as the magnetic analogue of the "shear-current" effect. Furthermore, given the inevitable existence of nonhelical small-scale magnetic fields in turbulent plasmas, as well as the generic nature of velocity shear, the suggested mechanism may help explain the generation of large-scale magnetic fields across a wide range of astrophysical objects.

  12. Nearshore internal bores and turbulent mixing in southern Monterey Bay

    NASA Astrophysics Data System (ADS)

    Walter, Ryan K.; Woodson, C. Brock; Arthur, Robert S.; Fringer, Oliver B.; Monismith, Stephen G.

    2012-07-01

    We observed transient stratification and mixing events associated with nearshore internal bores in southern Monterey Bay using an array of instruments with high spatial and temporal resolution. The arrival of the bores is characterized by surging masses of dense (cold) water that tend to stratify the water column. The bore is followed by a gradual drop in the temperature throughout the water column over several hours (defined here as the bore period) until a sharp warm-front relaxation, followed by high frequency temperature fluctuations, returns the column back to nearly its original state (defined here as the mixing period). Mixing periods revealed increased temperature variance at high frequencies (ω > N¯), as well as a greater percentage of events where dynamic instabilities may be present (Ri< 0.25), suggesting active mixing of the stratified water column. Turbulent dissipation rates in the stratified interior during the mixing period, estimated using the technique of isopycnal slope spectra, revealed mean values the same order of magnitude as near-bed bottom-generated turbulence. Observations indicate that local shear-produced turbulent kinetic energy by the warm front relaxations dominates mixing in the stratified interior. The non-canonical nature of these bore and relaxation events is also investigated with a numerical model, and the dynamics are shown to depend on the internal Iribarren number. Our results suggest that nearshore internal bores interacting with local bathymetry dramatically alter local dynamics and mixing in the nearshore with important ecological implications.

  13. Field stability of piezoelectric shear properties in PIN-PMN-PT crystals under large drive field.

    PubMed

    Zhang, Shujun; Li, Fei; Luo, Jun; Xia, Ru; Hackenberger, Wesley; Shrout, Thomas

    2011-02-01

    The coercive fields (E(C)) of Pb(In₀.₅Nb₀.₅)O₃-Pb(Mg(¹/₃)Nb(²/₃)O₃-PbTiO₃ (PIN-PMN-PT) ternary single crystals were found to be 5 kV/cm, double the value of binary Pb(Mg(¹/₃)Nb(²/₃)O₃-PbTiO₃ (PMNT) crystals, further increased to 6 to 9 kV/cm using Mn modifications. In addition to an increased EC, the acceptor modification resulted in the developed internal bias (E(int)), on the order of ~1 kV/cm. The piezoelectric shear properties of unmodified and Mn-modified PIN-PMN-PT crystals with various domain configurations were investigated. The shear piezoelectric coefficients and electromechanical coupling factors for different domain configurations were found to be >2000 pC/N and >0.85, respectively, with slightly reduced properties observed in Mn-modified tetragonal crystals. Fatigue/cycling tests performed on shearmode samples as a function of ac drive field level demonstrated that the allowable ac field levels (the maximum applied ac field before the occurrence of depolarization) were only ~2 kV/cm for unmodified crystals, less than half of their coercive field. Allowable ac drive levels were on the order of 4 to 6 kV/cm for Mn-modified crystals with rhombohedral/orthorhombic phase, further increased to 5 to 8 kV/cm in tetragonal crystals, because of their higher coercive fields. It is of particular interest that the allowable ac drive field level for Mn-modified crystals was found to be ≥ 60% of their coercive fields, because of the developed E(int), induced by the acceptor-oxygen vacancy defect dipoles.

  14. U.S. Geological Survey Combined Well-Bore Flow and Depth-Dependent Water Sampler

    USGS Publications Warehouse

    Izbicki, John A.; Christensen, Allen H.; Hanson, Randall T.; Martin, Peter; Crawford, Steven M.; Smith, Gregory A.

    1999-01-01

    The U.S. Geological Survey has developed a combined well-bore flow and depth-dependent sample collection tool. It is suitable for use in existing production wells having limited access and clearances as small as 1 inch. The combination of well-bore flow and depth-dependent water-quality data is especially effective in assessing changes in aquifer properties and water quality with depth. These are direct measures of changes in well yield and ground-water quality with depth under actual operating conditions. Combinations of other geophysical tools capable of making these measurements, such as vertical-axis current meters used with wire-line samplers, are commercially available but these tools are large and can not easily enter existing production wells.

  15. Galactic winds and the origin of large-scale magnetic fields

    NASA Astrophysics Data System (ADS)

    Moss, D.; Sokoloff, D.

    2017-02-01

    Context. Observations of dwarf galaxies suggest the presence of large-scale magnetic fields. However the size and slow rotation of these galaxies appear insufficient to support a mean-field dynamo action to excite such fields. Aims: Here we suggest a new mechanism to explain large-scale magnetic fields in galaxies that are too small to support mean-field dynamo action. The key idea is that we do not identify large-scale and mean magnetic fields. In our scenario the magnetic structures originate from a small-scale dynamo which produces small-scale magnetic field in the galactic disc and a galactic wind that transports this field into the galactic halo where the large turbulent diffusion increases the scale and order of the field. As a result, the magnetic field becomes large-scale; however its mean value remains vanishing in a strict sense. Methods: We verify the idea by numerical modelling of two distinct simplified configurations, a thin disc model using the no-z approximation, and an axisymmetric model using cylindrical r,z coordinates. Results: Each of these allows reduction of the problem to two spatial dimensions. Taken together, the models support the proposition that the general trends will persist in a fully 3D model. We demonstrate that a pronounced large-scale pattern can develop in the galactic halo for a wide choice of the dynamo governing parameters. Conclusions: We believe that our mechanism can be relevant to explaining the presence of the fields observed in the halos of dwarf galaxies, and maybe elsewhere. We emphasize that detailed modelling of the proposed scenario needs 3D simulations, and adjustment to the specific dynamo governing parameters of dwarf galaxies.

  16. Nonlinear Generation of shear flows and large scale magnetic fields by small scale

    NASA Astrophysics Data System (ADS)

    Aburjania, G.

    2009-04-01

    EGU2009-233 Nonlinear Generation of shear flows and large scale magnetic fields by small scale turbulence in the ionosphere by G. Aburjania Contact: George Aburjania, g.aburjania@gmail.com,aburj@mymail.ge

  17. Pulsar Rotation Measures and the Large-Scale Structure of the Galactic Magnetic Field

    NASA Astrophysics Data System (ADS)

    Han, J. L.; Manchester, R. N.; Lyne, A. G.; Qiao, G. J.; van Straten, W.

    2006-05-01

    The large-scale magnetic field of our Galaxy can be probed in three dimensions using Faraday rotation of pulsar signals. We report on the determination of 223 rotation measures from polarization observations of relatively distant southern pulsars made using the Parkes radio telescope. Combined with previously published observations, these data give clear evidence for large-scale counterclockwise fields (viewed from the north Galactic pole) in the spiral arms interior to the Sun and weaker evidence for a counterclockwise field in the Perseus arm. However, in interarm regions, including the solar neighborhood, we present evidence that suggests that large-scale fields are clockwise. We propose that the large-scale Galactic magnetic field has a bisymmetric structure with reversals on the boundaries of the spiral arms. Streaming motions associated with spiral density waves can directly generate such a structure from an initial, inwardly directed radial field. Large-scale fields increase toward the Galactic center, with a mean value of about 2 μG in the solar neighborhood and 4 μG at a galactocentric radius of 3 kpc.

  18. Sediment transport induced by tidal bores. An estimation from suspended matter measurements in the Sée River (Mont-Saint-Michel Bay, northwestern France)

    NASA Astrophysics Data System (ADS)

    Furgerot, Lucille; Mouazé, Dominique; Tessier, Bernadette; Perez, Laurent; Haquin, Sylvain; Weill, Pierre; Crave, Alain

    2016-07-01

    Tidal bores are believed to induce significant sediment transport in macrotidal estuaries. However, due to high turbulence and very large suspended sediment concentration (SSC), the measurement of sediment transport induced by a tidal bore is actually a technical challenge. Consequently, very few quantitative data have been published so far. This paper presents SSC measurements performed in the Sée River estuary (Mont-Saint-Michel Bay, northwestern France) during the tidal bore passage with direct and indirect (optical) methods. Both methods are calibrated in laboratory in order to verify the consistency of measurements, to calculate the uncertainties, and to correct the raw data. The SSC measurements coupled with ADCP velocity data are used to calculate the instantaneous sediment transport (qs) associated with the tidal bore passage (up to 40 kg/m2/s).

  19. High-Resolution Large-Field-of-View Ultrasound Breast Imager

    DTIC Science & Technology

    2014-08-01

    Ultrasound Breast Imager PRINCIPAL INVESTIGATOR: Patrick LaRiviere CONTRACTING...May 2014 4. TITLE AND SUBTITLE High-Resolution Large-Field-of-View Ultrasound Breast Imager 5a. CONTRACT NUMBER 5b. GRANT NUMBER W81XWH-11...work, we sought to construct and test the first practical full-field transmission ultrasound breast imaging system. The system will ultimately have a

  20. Wear analysis of disc cutters of full face rock tunnel boring machine

    NASA Astrophysics Data System (ADS)

    Zhang, Zhaohuang; Meng, Liang; Sun, Fei

    2014-11-01

    Wear is a major factor of disc cutters' failure. No current theory offers a standard for the prediction of disc cutter wear yet. In the field the wear prediction method commonly used is based on the excavation length of tunnel boring machine(TBM) to predict the disc cutter wear and its wear law, considering the location number of each disc cutter on the cutterhead(radius for installation); in theory, there is a prediction method of using arc wear coefficient. However, the preceding two methods have their own errors, with their accuracy being 40% or so and largely relying on the technicians' experience. Therefore, radial wear coefficient, axial wear coefficient and trajectory wear coefficient are defined on the basis of the operating characteristics of TBM. With reference to the installation and characteristics of disc cutters, those coefficients are modified according to penetration, which gives rise to the presentation of comprehensive axial wear coefficient, comprehensive radial wear coefficient and comprehensive trajectory wear coefficient. Calculation and determination of wear coefficients are made with consideration of data from a segment of TBM project(excavation length 173 m). The resulting wear coefficient values, after modification, are adopted to predict the disc cutter wear in the follow-up segment of the TBM project(excavation length of 5621 m). The prediction results show that the disc cutter wear predicted with comprehensive radial wear coefficient and comprehensive trajectory wear coefficient are not only accurate(accuracy 16.12%) but also highly congruous, whereas there is a larger deviation in the prediction with comprehensive axial wear coefficient(accuracy 41%, which is in agreement with the prediction of disc cutters' life in the field). This paper puts forth a new method concerning prediction of life span and wear of TBM disc cutters as well as timing for replacing disc cutters.

  1. Structure of an internal bore and dissipating gravity current as revealed by Raman lidar

    NASA Technical Reports Server (NTRS)

    Koch, Steven E.; Melfi, S. H.; Skillman, William C.; Whiteman, D.; Dorian, Paul B.; Ferrare, R.

    1991-01-01

    The Raman lidar observations of a weak gravity current and an internal bore associated with a thunderstorm gust front are presented. These observations have been complemented by conventional surface meteorologial analyses, special radiosonde data, spectral and bandpass filter analysis of barograph data, and infrared satellite imagery. Results obtained reveal the time-space continuity and dynamic nature of two boundary-layer disturbances seen in the lidar data. A comparison of the lidar display with the rawinsonde data makes it possible to determine the thermal fields associated with these disturbances at high temporal resolution (2 min) and an altitude of 6 km. The airflow associated with the disturbances was inferred by synthesizing the lidar and rawinsonde data. One of the two disturbances represents a dissipating outflow boundary (gust front) and can be characterized as a gravity current. The second disturbance represents an internal bore propagating ahead of the gravity current on a surface-based stable layer, which acted as a waveguide. The lidar revealed a mean bore depth of 1.9 km, observed and calculated speeds were in good agreement (about + or - 20 percent).

  2. Large-scale negative polarity magnetic fields on the sun and particle-emitting flares

    NASA Technical Reports Server (NTRS)

    Bumba, V.

    1972-01-01

    Some observational facts about the large-scale patterns formed by solar negative polarity magnetic fields during the 19th and 20th cycles of solar activity are presented. The close relation of the position of occurrence of very large flares accompanied by cosmic ray and PCA events as well as other phenomena of solar activity during the declining part of the 19th cycle of the regularities in the internal structure of large scale negative polarity features are demonstrated.

  3. Boring sponges, an increasing threat for coral reefs affected by bleaching events.

    PubMed

    Carballo, José L; Bautista, Eric; Nava, Héctor; Cruz-Barraza, José A; Chávez, Jesus A

    2013-04-01

    Coral bleaching is a stress response of corals induced by a variety of factors, but these events have become more frequent and intense in response to recent climate-change-related temperature anomalies. We tested the hypothesis that coral reefs affected by bleaching events are currently heavily infested by boring sponges, which are playing a significant role in the destruction of their physical structure. Seventeen reefs that cover the entire distributional range of corals along the Mexican Pacific coast were studied between 2005/2006, and later between 2009/2010. Most of these coral reefs were previously impacted by bleaching events, which resulted in coral mortalities. Sponge abundance and species richness was used as an indicator of bioerosion, and coral cover was used to describe the present condition of coral reefs. Coral reefs are currently highly invaded (46% of the samples examined) by a very high diversity of boring sponges (20 species); being the coral reef framework the substrate most invaded (56%) followed by the rubbles (45%), and the living colonies (36%). The results also indicated that boring sponges are promoting the dislodgment of live colonies and large fragments from the framework. In summary, the eastern coral reefs affected by bleaching phenomena, mainly provoked by El Niño, present a high diversity and abundance of boring sponges, which are weakening the union of the colony with the reef framework and promoting their dislodgment. These phenomena will probably become even more intense and severe, as temperatures are projected to continue to rise under the scenarios for future climate change, which could place many eastern coral reefs beyond their survival threshold.

  4. Boring sponges, an increasing threat for coral reefs affected by bleaching events

    PubMed Central

    Carballo, José L; Bautista, Eric; Nava, Héctor; Cruz-Barraza, José A; Chávez, Jesus A

    2013-01-01

    Coral bleaching is a stress response of corals induced by a variety of factors, but these events have become more frequent and intense in response to recent climate-change-related temperature anomalies. We tested the hypothesis that coral reefs affected by bleaching events are currently heavily infested by boring sponges, which are playing a significant role in the destruction of their physical structure. Seventeen reefs that cover the entire distributional range of corals along the Mexican Pacific coast were studied between 2005/2006, and later between 2009/2010. Most of these coral reefs were previously impacted by bleaching events, which resulted in coral mortalities. Sponge abundance and species richness was used as an indicator of bioerosion, and coral cover was used to describe the present condition of coral reefs. Coral reefs are currently highly invaded (46% of the samples examined) by a very high diversity of boring sponges (20 species); being the coral reef framework the substrate most invaded (56%) followed by the rubbles (45%), and the living colonies (36%). The results also indicated that boring sponges are promoting the dislodgment of live colonies and large fragments from the framework. In summary, the eastern coral reefs affected by bleaching phenomena, mainly provoked by El Niño, present a high diversity and abundance of boring sponges, which are weakening the union of the colony with the reef framework and promoting their dislodgment. These phenomena will probably become even more intense and severe, as temperatures are projected to continue to rise under the scenarios for future climate change, which could place many eastern coral reefs beyond their survival threshold. PMID:23610632

  5. Solar large-scale positive polarity magnetic fields and geomagnetic disturbances

    NASA Technical Reports Server (NTRS)

    Bumba, V.

    1972-01-01

    Unlike the negative polarity solar magnetic field large-scale regular features that correlate with enhanced solar activity regions, the positive polarity regular formations formed in the weak and old background magnetic fields seem to correlate well with geomagnetically enhanced periods of time (shifted for 4 days), which means that they seem to be the source of the quiet solar wind. This behavior of the large intervals of heliographic longitude with prevailing positive polarity fields may be followed to the end of the 18th cycle, during the declining part of the 19th cycle, and during the first half of the present 20th cycle of solar activity.

  6. Large aperture laser beam alignment system based on far field sampling technique

    NASA Astrophysics Data System (ADS)

    Zhang, J. C.; Liu, D. Z.; Ouyang, X. P.; Kang, J.; Xie, X. L.; Zhou, J.; Gong, L.; Zhu, B. Q.

    2016-11-01

    Laser beam alignment is very important for high-power laser facility. Long laser path and large-aperture lens for alignment are generally used, while the proposed alignment system with a wedge by far-field sampling technique reduces both space and cost requirements. General alignment system for large-aperture laser beam is long in distance and large in volum because of taking near-field sampling technique. With the development of laser fusion facilities, the space for alignment system is limited. A new alignment system for large-aperture laser beam is designed to save space and reduce operating costs. The new alignment for large-aperture laser beam with a wedge is based on far-field sampling technique. The wedge is placed behind the spatial filter to reflect some laser beam as signal light for alignment. Therefore, laser beam diameter in alignment system is small, which can save space for the laser facility. Comparing to general alignment system for large-aperture laser beam, large-aperture lenses for near-field and far-field sampling, long distance laser path are unnecessary for proposed alignment system, which saves cost and space greatly. This alignment system for large-aperture laser beam has been demonstrated well on the Muliti-PW Facility which uses the 7th beam of the SG-Ⅱ Facility as pump source. The experimental results indicate that the average near-field alignment error is less than 1% of reference, and the average far-filed alignment error is less than 5% of spatial filter pinhole diameter, which meet the alignment system requirements for laser beam of Multi-PW Facility.

  7. High-field QCPMG NMR of large quadrupolar patterns using resistive magnets.

    PubMed

    Hung, Ivan; Shetty, Kiran; Ellis, Paul D; Brey, William W; Gan, Zhehong

    2009-12-01

    Spectroscopy in a high magnetic field reduces second-order quadrupolar shift while increasing chemical shift. It changes the scale between quadrupolar and chemical shift of half-integer quadrupolar spins. The application of QCPMG multiple echo for acquiring large quadrupolar pattern under the high magnetic field of a 25 T resistive magnet is presented for acquiring large quadrupolar patterns. It shows that temporal field fluctuations and spatial homogeneity of the Keck magnet at the NHMFL contribute about +/- 20 ppm in line broadening. NMR patterns which have breadths of hundreds to thousands of kilohertz can be efficiently recorded using a combination of QCPMG and magnetic field stepping with negligible hindrance from the inhomogeneity and field fluctuations of powered magnets.

  8. Structure and evolution of the large scale solar and heliospheric magnetic fields. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Hoeksema, J. T.

    1984-01-01

    Structure and evolution of large scale photospheric and coronal magnetic fields in the interval 1976-1983 were studied using observations from the Stanford Solar Observatory and a potential field model. The solar wind in the heliosphere is organized into large regions in which the magnetic field has a componenet either toward or away from the sun. The model predicts the location of the current sheet separating these regions. Near solar minimum, in 1976, the current sheet lay within a few degrees of the solar equator having two extensions north and south of the equator. Soon after minimum the latitudinal extent began to increase. The sheet reached to at least 50 deg from 1978 through 1983. The complex structure near maximum occasionally included multiple current sheets. Large scale structures persist for up to two years during the entire interval. To minimize errors in determining the structure of the heliospheric field particular attention was paid to decreasing the distorting effects of rapid field evolution, finding the optimum source surface radius, determining the correction to the sun's polar field, and handling missing data. The predicted structure agrees with direct interplanetary field measurements taken near the ecliptic and with coronameter and interplanetary scintillation measurements which infer the three dimensional interplanetary magnetic structure. During most of the solar cycle the heliospheric field cannot be adequately described as a dipole.

  9. Pressure versus current scaling in a blocked bore rail gun

    NASA Astrophysics Data System (ADS)

    Barrett, B. D.; Eubank, Eric; Nunnally, W. C.

    1993-07-01

    The paper presents experimental results from a blocked bore plasma armature rail gun. A piezoelectric transducer mounted in the bore blocking structure recorded time-resolved pressures over a range of input currents from 50 to 150 kA. The bore block is located at four positions where peak current occurs for the four respective charging voltages to power the system. Problems associated with obtaining these measurements and the solutions employed are discussed. Average distances from the block face to the armature current centroid are estimated assuming a pressure balance between the magnetic and neutral pressures. The averages of the measured pressures were found to be proportional to the input current raised to the power of 1.655.

  10. A large depth of field frontal multi-projection three-dimensional display with uniform light field distribution

    NASA Astrophysics Data System (ADS)

    Wang, Peng; Xie, Songlin; Sang, Xinzhu; Chen, Duo; Li, Chenyu; Gao, Xin; Yu, Xunbo; Yu, Chongxiu; Yan, Binbin; Dou, Wenhua; Xiao, Liquan

    2015-11-01

    To achieve an immersive three-dimensional (3D) experience, a frontal multi-projection (FMP) 3D display with a large screen is presented. In order to increase the angular resolution and the depth of field of the 3D display, a configuration method of the projector array is presented to arrange more projectors within a limited space. The projectors are arranged at different periods of the light field with the rows repeatedly changed according to a predetermined row interval. The luminance characteristics are analyzed and the projector array is optimized to minimize the brightness fluctuation of the reproduced light field. Different configurations of the array for the 3D display are experimentally investigated. The demonstrated 85-in. frontal multi-projection 3D display can provide a good 3D visual experience with the displayed clear depth of field of 1.18 m and uniform brightness. The view angle along the optimal viewing distance of 4 m is 48°.

  11. Large-scale, near-field magnetic fields from external sources and the corresponding induced internal field

    NASA Technical Reports Server (NTRS)

    Langel, R. A.; Estes, R. H.

    1985-01-01

    Data from Magsat analyzed as a function of the Dst index to determine the first degree/order spherical harmonic description of the near-earth external field and its corresponding induced field. The analysis was done separately for data from dawn and dusk. The Magsat data was compared with POGO data. A local time variation of the external field persists even during very quiet magnetic conditions; both a diurnal and 8-hour period are present. A crude estimate of Sq current in the 45 deg geomagnetic latitude range is obtained for 1966 to 1970. The current strength, located in the ionosphere and induced in the earth, is typical of earlier determinations from surface data, although its maximum is displaced in local time from previous results.

  12. Automated tracing of open-field coronal structures for an optimized large-scale magnetic field reconstruction

    NASA Astrophysics Data System (ADS)

    Uritsky, V. M.; Davila, J. M.; Jones, S. I.

    2014-12-01

    Solar Probe Plus and Solar Orbiter will provide detailed measurements in the inner heliosphere magnetically connected with the topologically complex and eruptive solar corona. Interpretation of these measurements will require accurate reconstruction of the large-scale coronal magnetic field. In a related presentation by S. Jones et al., we argue that such reconstruction can be performed using photospheric extrapolation methods constrained by white-light coronagraph images. Here, we present the image-processing component of this project dealing with an automated segmentation of fan-like coronal loop structures. In contrast to the existing segmentation codes designed for detecting small-scale closed loops in the vicinity of active regions, we focus on the large-scale geometry of the open-field coronal features observed at significant radial distances from the solar surface. The coronagraph images used for the loop segmentation are transformed into a polar coordinate system and undergo radial detrending and initial noise reduction. The preprocessed images are subject to an adaptive second order differentiation combining radial and azimuthal directions. An adjustable thresholding technique is applied to identify candidate coronagraph features associated with the large-scale coronal field. A blob detection algorithm is used to extract valid features and discard noisy data pixels. The obtained features are interpolated using higher-order polynomials which are used to derive empirical directional constraints for magnetic field extrapolation procedures based on photospheric magnetograms.

  13. A Field Cancellation Algorithm for Constructing Economical Planar Permanent Magnet (PM) Multipoles With Large High Quality Field Apertures

    SciTech Connect

    Tatchyn, Roman; /SLAC

    2011-08-12

    In recent years studies have been initiated on a new class of multipole field generators consisting of cuboid planar permanent magnet (PM) pieces arranged in biplanar arrays of 2-fold rotational symmetry. These structures, first introduced for Free Electron Laser (FEL) applications, are based on reducing the rotational symmetry of conventional N-pole field generators from N-fold to 2-fold. One consequence of this reduction is a large higher-multipole content in a planar PM multipole's field at distances relatively close to the structure's axis, making it generally unsuitable for applications requiring a large high-quality field aperture. In this paper we outline an economical field-cancellation algorithm that can substantially decrease the harmonic content of a planar PM's field without breaking its biplanar geometry or 2-fold rotational symmetry. An economical field-cancellation algorithm has been described which will allow the fabrication of bi-planar quadrupoles and sextupoles with high-quality fields using a manageably small number of PM pieces. For higher order N-poles the number of pieces required to cancel a given number of successively-higher multipole components will also increase linearly; nevertheless, the practicability of fabricating octupoles and higher N-poles of this type should be considered a subject of continuing r&d. Since the removal of a large number of successive multipole components essentially increases the transverse region over which the N-pole's field is dominated by its leading N-pole field component, the fabrication of quadrupoles and sextupoles of the type described in this paper should lead to their introduction in storage ring applications. One potentially important application in this area is as distributed focusing elements installed into very-short-period, small-gap undulators (e.g., as a FODO lattice). The installation is rendered feasible by the very small vertical height of the biplanar N-poles (on the order of a millimeter

  14. Continuous measurements of in-bore projectile velocity

    SciTech Connect

    Asay, J.R.; Konrad, C.H.; Hall, C.A.; Shahinpoor, M.; Hickman, R.

    1988-01-01

    The application of velocity interferometry to the continuous measurement of in-bore projectile velocity in a small-bore three-stage railgun is described. These measurements are useful for determining projectile acceleration and for evaluating gun performance. The launcher employed in these studies consists of a two-stage light gas gun used to inject projectiles into a railgun for additional acceleration. Results obtained for projectile velocities to 7.4 km/s with the two-stage injector are reported and potential improvements for railgun applications are discussed. 12 refs., 7 figs.

  15. Does Polishing a Rifle Bore Reduce Bullet Drag?

    DTIC Science & Technology

    2012-01-17

    thus lower drag. A Remington 700 5R Mil-Spec chambered in 300 Winchester Magnum was used. The bullets used were a 155.5 grain Berger Fullbore Boat...drag on the bullets. 15. SUBJECT TERMS Ballistic coefficient, aerodynamic drag, rifle bore, bore polishing, Remington 700 5R 16. SECURITY...A Remington 700 5R Mil-Spec chambered in 300 Winchester Magnum was used. The bullets used were a 155.5 grain Berger Fullbore Boat Tail and a 125

  16. Grinding tool for making hemispherical bores in hard materials

    DOEpatents

    Duran, E.L.

    1985-04-03

    A grinding tool for forming hemispherical bores in hard materials such as boron carbide. The tool comprises a hemicircular grinding bit, formed of a metal bond diamond matrix, which is mounted transversely on one end of a tubular tool shaft. The bit includes a spherically curved outer edge surface which is the active grinding surface of the tool. Two coolant fluid ports on opposite sides of the bit enable introduction of coolant fluid through the bore of the tool shaft so as to be emitted adjacent the opposite sides of the grinding bit, thereby providing optimum cooling of both the workpiece and the bit.

  17. Seismic source characterisation of a Tunnel Boring Machine (TBM)

    NASA Astrophysics Data System (ADS)

    Kreutzer, Ingrid; Brückl, Ewald; Radinger, Alexander

    2015-04-01

    The Tunnel Seismic While Drilling (TSWD) method aims at predicting continuously the geological situation ahead of the tunnel without disturbing the construction work. Thereby the Tunnel Boring Machine (TBM) itself is used as seismic source. The cutting process generates seismic waves radiating into the rock mass and vibrations propagating to the main bearing of the cutter head. These vibrations are monitored and used as pilot signal. For the processing and interpretation it was hypothesized so far that the TBM acts like a single force. To prove this assumption the radiation pattern of several TBM's under construction were investigated. Therefore 3-components geophones were installed at the surface, which were situated directly above the tunnel axes and also with lateral offset. Additional, borehole geophones were placed in the wall of one tube of a two-tube tunnel. The geophones collected the forward and backward radiated wave field, as the TBM, operating in the other tube, passed their positions. The obtained seismic data contains continuous records over a range of 600 m of the TBM position. The offsets vary from 25 m to 400 m and the frequency ranges from 20-250 Hertz. The polarisation of the p-wave and the s-wave and their amplitude ratio were determined and compared with modelled seismograms with different source mechanism. The results show that the description of the source mechanism by a single force can be used as a first order approximation. More complex radiation pattern including tensile forces and several source locations like the transmission of reaction forces over the gripper to the tunnel wall are further tested and addressed.

  18. The relationship of the large-scale solar field to the interplanetary magnetic field - What will Ulysses find?

    NASA Technical Reports Server (NTRS)

    Hoeksema, J. T.

    1986-01-01

    Using photospheric magnetic field observations obtained at the Stanford Wilcox Solar Observatory, results from a potential field model for the present solar cycle are given, and qualitative predictions of the IMF that Ulysses may encounter are presented. Results indicate that the IMF consists of large regions of opposite polarity separated by a neutral sheet (NS) (extended to at least 50 deg) and a four-sector structure near solar minimum (produced by small quadripolar NS warps). The latitudinal extent of the NS increases following minimum and the structure near maximum includes multiple NSs, while a simplified IMF is found during the declining phase.

  19. Efficient Simulation and Downscaling of Large Non-Stationary Fields with Varying Local Anisotropy

    NASA Astrophysics Data System (ADS)

    Dodov, B.

    2015-12-01

    Simulation of locally anisotropic, non-stationary random fields is a relatively new topic in geostatistics with applications currently restricted to the construction of an admissible covariance matrix. In this paper, we introduce an efficient algorithm for constructing large non-stationary random fields with arbitrary local covariance structure and anisotropy. At the heart of our approach is a newly developed robust directional multiresolution framework combined with a local tensor anisotropy model. The use of our algorithm is illustrated with local anisotropy analysis, simulation and downscaling of complex pseudo-precipitation (PP) fields* related to tropical and extra-tropical cyclones. The efficiency of the algorithm allows obtaining realistic downscaled global GCM precipitation fields down to a few kilometers resolution in seconds.* Reference: Unpublished work by Huiling Yuan and Zoltan Toth. PP fields are constructed by taking the precipitation as the positive component of the field and the water vapor saturation deficit as its negative complement.

  20. A New Facility for Testing Superconducting Solenoid Magnets with Large Fringe Fields at Fermilab

    SciTech Connect

    Orris, D.; Carcagno, R.; Nogiec, J.; Rabehl, R.; Sylvester, C.; Tartaglia, M.

    2013-09-01

    Testing superconducting solenoid with no iron flux return can be problematic for a magnet test facility due to the large magnetic fringe fields generated. These large external fields can interfere with the operation of equipment while precautions must be taken for personnel supporting the test. The magnetic forces between the solenoid under test and the external infrastructure must also be taken under consideration. A new test facility has been designed and built at Fermilab specifically for testing superconducting magnets with large external fringe fields. This paper discusses the test stand design, capabilities, and details of the instrumentation and controls with data from the first solenoid tested in this facility: the Muon Ionization Cooling Experiment (MICE) coupling coil.

  1. Turbulence and magnetic fields in the large-scale structure of the universe.

    PubMed

    Ryu, Dongsu; Kang, Hyesung; Cho, Jungyeon; Das, Santabrata

    2008-05-16

    The nature and origin of turbulence and magnetic fields in the intergalactic space are important problems that are yet to be understood. We propose a scenario in which turbulent-flow motions are induced via the cascade of the vorticity generated at cosmological shocks during the formation of the large-scale structure. The turbulence in turn amplifies weak seed magnetic fields of any origin. Supercomputer simulations show that the turbulence is subsonic inside clusters and groups of galaxies, whereas it is transonic or mildly supersonic in filaments. Based on a turbulence dynamo model, we then estimated that the average magnetic field strength would be a few microgauss (microG) inside clusters and groups, approximately 0.1 muG around clusters and groups, and approximately 10 nanogauss in filaments. Our model presents a physical mechanism that transfers the gravitational energy to the turbulence and magnetic field energies in the large-scale structure of the universe.

  2. Manifestations of dynamo driven large-scale magnetic field in accretion disks of compact objects

    NASA Technical Reports Server (NTRS)

    Chagelishvili, G. D.; Chanishvili, R. G.; Lominadze, J. G.; Sokhadze, Z. A.

    1991-01-01

    A turbulent dynamo nonlinear theory of turbulence was developed that shows that in the compact objects of accretion disks, the generated large-scale magnetic field (when the generation takes place) has a practically toroidal configuration. Its energy density can be much higher than turbulent pulsations energy density, and it becomes comparable with the thermal energy density of the medium. On this basis, the manifestations to which the large-scale magnetic field can lead at the accretion onto black holes and gravimagnetic rotators, respectively, are presented.

  3. Reduction of the field-aligned potential drop in the polar cap during large geomagnetic storms

    NASA Astrophysics Data System (ADS)

    Kitamura, N.; Seki, K.; Nishimura, Y.; Hori, T.; Terada, N.; Ono, T.; Strangeway, R. J.

    2013-12-01

    We have studied photoelectron flows and the inferred field-aligned potential drop in the polar cap during 5 large geomagnetic storms that occurred in the periods when the photoelectron observations in the polar cap were available near the apogee of the FAST satellite (~4000 km) at solar maximum, and the footprint of the satellite paths in the polar cap was under sunlit conditions most of the time. In contrast to the ~20 V potential drop during geomagnetically quiet periods at solar maximum identified by Kitamura et al. [JGR, 2012], the field-aligned potential drop frequently became smaller than ~5 V during the main and early recovery phases of the large geomagnetic storms. Because the potential acts to inhibit photoelectron escape, this result indicates that the corresponding acceleration of ions by the field-aligned potential drop in the polar cap and the lobe region is smaller during the main and early recovery phases of large geomagnetic storms compared to during geomagnetically quiet periods. Under small field-aligned current conditions, the number flux of outflowing ions should be nearly equal to the net escaping electron number flux. Since ions with large flux originating from the cusp/cleft ionosphere convect into the polar cap during geomagnetic storms [e.g., Kitamura et al., JGR, 2010], the net escaping electron number flux should increase to balance the enhanced ion outflows. The magnitude of the field-aligned potential drop would be reduced to let a larger fraction of photoelectrons escape.

  4. Exact asymptotics of the current in boundary-driven dissipative quantum chains in large external fields

    NASA Astrophysics Data System (ADS)

    Lenarčič, Zala; Prosen, Tomaž

    2015-03-01

    A boundary-driven quantum master equation for a general inhomogeneous (nonintegrable) anisotropic Heisenberg spin-1 /2 chain, or an equivalent nearest neighbor interacting spinless fermion chain, is considered in the presence of a strong external field f . We present an exact closed form expression for large f asymptotics of the current in the presence of a pure incoherent source and sink dissipation at the boundaries. In application, we demonstrate an arbitrary large current rectification in the presence of the interaction.

  5. Test Results of 15 T Nb3Sn Quadrupole Magnet HQ01 with a 120 mm Bore for the LHC Luminosity Upgrade

    SciTech Connect

    Caspi, S.; Schmalzle, J.; Ambrosio, G.; Anerella, M.; Barzi, E.; Bingham, B.; Bossert, R.; Cheng, D.W.; Chlachidze, G.; Dietderich, D.R.; Felice, H.; Ferracin, P.; Ghosh, A.; Hafalia, A.R.; Hannaford, C.R.; Joseph, J.; Kashikhin, V.V.; Sabbi, G.L.; Schmalzle, J.; Wanderer,; P.l Xiaorong, W.; Zlobin, A.V.

    2011-08-03

    In support of the luminosity upgrade of the Large Hadron Collider (LHC), the US LHC Accelerator Research Program (LARP) has been developing a 1-meter long, 120 mm bore Nb{sub 3}Sn IR quadrupole magnet (HQ). With a short sample gradient of 219 T/m at 1.9 K and a conductor peak field of 15 T, the magnet will operate under higher forces and stored-energy levels than that of any previous LARP magnet models. In addition, HQ has been designed to incorporate accelerator quality features such as precise coil alignment and adequate cooling. The first 6 coils (out of the 8 fabricated so far) have been assembled and used in two separate tests-HQ01a and HQ01b. This paper presents design parameters, summary of the assemblies, the mechanical behavior as well as the performance of HQ01a and HQ01b.

  6. Test Results of 15 T Nb{sub 3}Sn Quadrupole Magnet HQ01 with a 120 mm Bore for the LHC Luminosity Upgrade

    SciTech Connect

    Caspi, S.; Ambrosio, G.; Anerella, M.; Barzi, E.; Bingham, B.; Bossert, R.; Cheng, D. W.; Chlachidze, G.; Dietderich, D. R.; Felice, H.; Ferracin, P.; Ghosh, A.; Hafalia, A. R.; Hannaford, C. R.; Joseph, J.; Kashikhin, V. V.; Sabbi, G. L.; Schmalzle, J.; Wang, X.; Zlobin, A. V.

    2010-08-01

    In support of the luminosity upgrade of the Large Hadron Collider (LHC), the US LHC Accelerator Research Program (LARP) has been developing a 1-meter long, 120 mm bore Nb3 Sn IR quadrupole magnet (HQ). With a short sample gradient of 219 T/m at 1.9 K and a conductor peak field of 15 T, the magnet will operate under higher forces and stored-energy levels than that of any previous LARP magnet models. In addition, HQ has been designed to incorporate accelerator quality features such as precise coil alignment and adequate cooling. The first 6 coils (out of the 8 fabricated so far) have been assembled and used in two separate tests-HQ01a and HQ01b. This paper presents design parameters, summary of the assemblies, the mechanical behavior as well as the performance of HQ01a and HQ01b.

  7. Internal bore seasonality and tidal pumping of subthermocline waters at the head of the Monterey submarine canyon

    NASA Astrophysics Data System (ADS)

    Walter, Ryan K.; Phelan, P. Joe

    2016-03-01

    This study utilizes more than a year of observations made in shallow waters (~30 m) at the head of the Monterey Submarine Canyon to assess variability in the physical environment and internal bore field. The interaction of the internal tide with the canyon rim results in a semidiurnal tidal period pumping of cold-water masses (subthermocline waters) onto the adjacent shelf (i.e., internal bores). These internal bores are shown to be significantly coherent with the local sea surface height with minimal spatial variability when comparing two sites near the canyon head region. During the summer months, and periods of strong regional wind-driven upwelling and shoaling of the offshore thermocline, the canyon rim sites display elevated semidiurnal temperature variance. This semidiurnal variability reaches its annual minimum during the winter months when the regional upwelling favorable winds subside and the offshore thermocline deepens. Additionally, the observed internal bores show a distinct asymmetry between the leading (gradual cooling with velocities directed onto the shelf) and trailing edges (sharp warming with velocities directed into the canyon). It appears that the semidiurnal internal tide at the canyon head is a first-order control on the delivery of subthermocline waters to the nearshore coastal environment at this location.

  8. Internal Bore Seasonality and Tidal Pumping of Subthermocline Waters at the Head of the Monterey Submarine Canyon

    NASA Astrophysics Data System (ADS)

    Walter, R. K.; Phelan, J.

    2015-12-01

    This study utilizes more than a year of observations made in shallow waters (~30 m) at the head of the Monterey Submarine Canyon to assess variability in the physical environment and internal bore field. The interaction of the internal tide with the canyon rim results in a semidiurnal tidal period pumping of cold water intrusions (subthermocline waters) onto the adjacent shelf (i.e., internal bores). These internal bores are shown to be significantly coherent with the surface (barotropic) tide with minimal spatial variability when comparing two sites on opposite sides of the canyon head. During the summer months, and periods of strong regional wind-driven upwelling and shoaling of the offshore thermocline, the canyon rim sites display elevated semidiurnal temperature variance. The semidiurnal variability reaches its annual minimum during the winter months when the regional upwelling favorable winds subside and the offshore thermocline deepens. Additionally, the observed internal bores show a distinct asymmetry between the leading (gradual cooling with velocities directed onto the shelf) and trailing edges (sharp warming with velocities directed into the canyon). It appears that the semidiurnal internal tide at the canyon head is a first-order control on the delivery of subthermocline waters to the nearshore coastal environment at this location.

  9. 4. VIEW OF VERTICAL BORING MACHINE. (Bullard) Vertical turning lathe ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. VIEW OF VERTICAL BORING MACHINE. (Bullard) Vertical turning lathe (VTL). Machining the fixture for GE Turboshroud. G.S. O'Brien, operator. - Juniata Shops, Machine Shop No. 1, East of Fourth Avenue at Third Street, Altoona, Blair County, PA

  10. Boring and Drilling Tools. Pre-Apprenticeship Phase 1 Training.

    ERIC Educational Resources Information Center

    Lane Community Coll., Eugene, OR.

    This self-paced student training module on boring and drilling tools is one of a number of modules developed for Pre-apprenticeship Phase 1 Training. Purpose of the module is to enable students to identify, select, and understand the proper use of many common awls, bits, and drilling tools. The module may contain some or all of the following: a…

  11. 2. GENERAL VIEW OF HYDRAULIC 48' BORING MILL. Manufactured by ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. GENERAL VIEW OF HYDRAULIC 48' BORING MILL. Manufactured by Simmons Machine Tool Corporation, Albany, New York, and Betts Company, a division of Niles Tool Company, Hamilton, Ohio. - Juniata Shops, Erecting Shop & Machine Shop, East of Fourth Avenue, between Fourth & Fifth Streets, Altoona, Blair County, PA

  12. Preliminary list of deep borings in the United States

    USGS Publications Warehouse

    Darton, Nelson Horatio

    1905-01-01

    The first preliminary list of deep borings in the United States was issued as Water-Supply Papers Nos. 57 and 61. The present publication includes all of the wells listed in these two papers, together with many additional borings, mostly of recent date. Messrs. M. L. Fuller and A. C. Veatch, of the eastern section of hydrology, and other geologists of the Survey have contributed many new data. Descriptions of borings published in reports issued since 1901 have been incorporated as far as practicable. All the entries are by counties. The wells and borings reported in the paper are all more than 400 feet in depth. The information concerning them has been obtained partly from replies to circular letters sent to all parts of the United States and partly from geological reports and other published sources. Owing to the difficulty of obtaining replies to the circulars, to lack of knowledge on the part of correspondents, and to the incompleteness of published records, doubtless there are borings which have not been reported. In regions of oil and gas wells, where borings are numerous, the individual wells can not be listed here, but representative wells are given. References to logs or records of the wells or extended descriptions of them are given in footnotes, and after the list of wells in each State there is added a list of the principal publications relating to deep borings in that State.The bearing of the information given in the columns of the lists probably is apparent unless, perhaps, in the one headed "Height to which the water rises." In this column an entry such as "-45" indicates that the water rises to within 45 feet of the surface; "+45" indicates that it is a flowing well and has sufficient head to raise the water 45 feet above the surface in an open pipe 45 feet or more in height. The yield in gallons per minute usually is estimated. Depths and diameters often have been reported from memory and different sources of publication sometimes give different

  13. Comparing the Large-Scale Magnetic Field During the Last Three Solar Cycles (Invited)

    NASA Astrophysics Data System (ADS)

    Hoeksema, J. T.

    2009-12-01

    Large-scale magnetic field observations show that the current extended solar cycle minimum differs from the two previous well-observed minima in several respects. The weaker polar fields increase the relative influence of middle and low-latitude flux patterns on the configuration of the corona and heliosphere. A much larger fraction of the open flux originates in equatorial coronal holes. Even though the heliospheric field magnitude and the mean solar magnetic field are the weakest since direct measurements began, the sector structure of the interplanetary field that reflects the shape of the heliospheric current sheet continues to extend to fairly high latitude. The pattern of emergence of active regions through the cycle and the transport of flux from low to high latitudes also show quite different patterns, providing insight into the meridional flow that influences the dynamo that drives the cycle. The long records of synoptic observations that provide a rich source of information about solar activity must be maintained.

  14. Field line and Particle orbit Analysis in the Periphery of the Large Helical Device

    NASA Astrophysics Data System (ADS)

    Matsumoto, Yutaka; Oikawa, Shun-ichi; Watanabe, Tsuguhiro

    2002-07-01

    Magnetic field lines and particle orbits were analyzed in the periphery of the Large Helical Device (LHD), which is called the chaotic field line region in this paper. The widths of the chaotic field line region were numerically identified for the standard LHD configuration with the magnetic axis position Rax = 3.75 m and for an improved confinement configuration with Rax = 3.6 m. It was found that the reflected particles include of what we have named chaotic particles and non-chaotic particles. Most of the reflected particles are mirror-confined with strong adiabaticity in the chaotic field line region. The remaining reflected particles, named type-A and type-B particles, are harmful to confinement. We found by detailed analysis of the vacuum magnetic field in the LHD that there exist loss canals that are the open intersections of |\\mbi{B}| = const. and \\mbi{B} \\cdot \

  15. Design, construction and use of a large-sample field-cycled PEDRI imager

    NASA Astrophysics Data System (ADS)

    Lurie, David J.; Foster, Margaret A.; Yeung, David; Hutchison, James M. S.

    1998-07-01

    The design, construction and use of a large-scale field-cycled proton-electron double-resonance imaging (FC-PEDRI) imager is described. The imager is based on a whole-body sized, vertical field, 59 mT permanent magnet. Field cycling is accomplished by the field compensation method, and uses a secondary, resistive magnet with an internal diameter of 52 cm. The magnetic field can be switched from zero to 59 mT or vice versa in 40 ms. It is used with a double-resonance coil assembly (NMR/EPR) comprising a solenoidal NMR transmit/receive coil and a coaxial, external birdcage resonator for EPR irradiation. Experiments to image the distribution of an exogenous nitroxide free radical in anaesthetized rabbits are described.

  16. Design, construction and use of a large-sample field-cycled PEDRI imager.

    PubMed

    Lurie, D J; Foster, M A; Yeung, D; Hutchison, J M

    1998-07-01

    The design, construction and use of a large-scale field-cycled proton-electron double-resonance imaging (FC-PEDRI) imager is described. The imager is based on a whole-body sized, vertical field, 59 mT permanent magnet. Field cycling is accomplished by the field compensation method, and uses a secondary, resistive magnet with an internal diameter of 52 cm. The magnetic field can be switched from zero to 59 mT or vice versa in 40 ms. It is used with a double-resonance coil assembly (NMR/EPR) comprising a solenoidal NMR transmit/receive coil and a coaxial, external birdcage resonator for EPR irradiation. Experiments to image the distribution of an exogenous nitroxide free radical in anaesthetized rabbits are described.

  17. Effective field theory for large logarithms in radiative corrections to electron proton scattering

    NASA Astrophysics Data System (ADS)

    Hill, Richard J.

    2017-01-01

    Radiative corrections to elastic electron proton scattering are analyzed in effective field theory. A new factorization formula identifies all sources of large logarithms in the limit of large momentum transfer, Q2≫me2. Explicit matching calculations are performed through two-loop order. A renormalization analysis in soft-collinear effective theory is performed to systematically compute and resum large logarithms. Implications for the extraction of charge radii and other observables from scattering data are discussed. The formalism may be applied to other lepton-nucleon scattering and e+e- annihilation processes.

  18. Canyon drainage induced mixing over a large basin

    SciTech Connect

    Stalker, J.

    2000-05-01

    Complex terrain surrounding urbanized basins around the world has long been recognized to strongly affect the characteristics of vertical transport and mixing of pollutants. The Department of Energy's Vertical Transport and Mixing (VTMX) program will investigate mixing processes within night-time boundary layers over large urban basins. The program will launch several field experiments within the Salt Lake City basin in the coming years. This modeling study, like many other studies being undertaken by the participants of the VTMX programs, is intended to complement the proposed field experiments by numerically examining some of the flow interactions known to occur in large basins. Using idealized simulations, we particularly investigate drainage flows from deep canyons similar to those along the Wasatch Front into the Salt Lake City basin. Literature shows that under favorable conditions, drainage flows can generate bore waves that may propagate ahead of the density current (e.g., Simpson 1969; Simpson 1982; Crook and Miller 1985). Existence and frequency of such bore waves can profoundly influence the spatial and temporal variability of vertical transport and mixing within large basins. If bore waves do occur on a regular basis within the Salt Lake City basin (a task for the upcoming experiments to determine), then understanding the basin-scale conditions under which these waves are produced and how they may propagate and interact with the city's buildings will be of great importance in characterizing transport and mixing processes within the basin.

  19. Identification of large masses of citrus fruit and rice fields in eastern Spain

    NASA Technical Reports Server (NTRS)

    Desagredo, F. L.; Salinas, F. G.

    1973-01-01

    ERTS-1 imagery has been successfully used for the identification of large areas of citrus groves and rice fields in the Valencia region of Eastern Spain. Results are encouraging and will facilitate the elaboration of a land use map with a fair degree of definition once methods prove to be fully operational.

  20. Insecticide treated and untreated Bt and conventional cottons under high insect pressure in large field cages

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Early maturing Bt cottons (DP0912 and PHY375), early maturing conventional cottons (ARK48 and DP121), a full season Bt cotton (DP1048) and full season conventional cottons (MD25 and DP174) were grown in large field cages and exposed to high densities of bollworm and tobacco budworm moths over a thr...

  1. Destruction of large-scale magnetic field in non-linear simulations of the shear dynamo

    NASA Astrophysics Data System (ADS)

    Teed, Robert J.; Proctor, Michael R. E.

    2016-05-01

    The Sun's magnetic field exhibits coherence in space and time on much larger scales than the turbulent convection that ultimately powers the dynamo. In the past the α-effect (mean-field) concept has been used to model the solar cycle, but recent work has cast doubt on the validity of the mean-field ansatz under solar conditions. This indicates that one should seek an alternative mechanism for generating large-scale structure. One possibility is the recently proposed `shear dynamo' mechanism where large-scale magnetic fields are generated in the presence of a simple shear. Further investigation of this proposition is required, however, because work has been focused on the linear regime with a uniform shear profile thus far. In this paper we report results of the extension of the original shear dynamo model into the non-linear regime. We find that whilst large-scale structure can initially persist into the saturated regime, in several of our simulations it is destroyed via large increase in kinetic energy. This result casts doubt on the ability of the simple uniform shear dynamo mechanism to act as an alternative to the α-effect in solar conditions.

  2. FIELD DEMONSTRATION OF EMERGING PIPE WALL INTEGRITY ASSESSMENT TECHNOLOGIES FOR LARGE CAST IRON WATER MAINS

    EPA Science Inventory

    The U.S. Environmental Protection Agency sponsored a large-scale field demonstration of innovative leak detection/location and condition assessment technologies on a 76-year old, 2,500-ft long, cement-lined, 24-in. cast iron water main in Louisville, KY from July through Septembe...

  3. Field Demonstration of Emerging Pipe Wall Integrity Assessment Technologies for Large Cast Iron Water Mains - Paper

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) sponsored a large-scale field demonstration of innovative leak detection/location and condition assessment technologies on a 76-year old, 2,000-ft long, cement-lined, 24-in. cast-iron water main in Louisville, KY from July through Se...

  4. SU-E-T-404: Simple Field-In-Field Technique for Total Body Irradiation in Large Patients

    SciTech Connect

    Chi, P; Pinnix, C; Dabaja, B; Wang, C; Aristophanous, M; Tung, S

    2014-06-01

    Purpose: A simple Field-in-Field technique for Total Body Irradiation (TBI) was developed for traditional AP/PA TBI treatments to improve dosimetric uniformity in patients with large separation. Methods: TBI at our institution currently utilizes an AP/PA technique at an extended source-to-surface distance (SSD) of 380cm with patients in left decubitus position during the AP beam and in right decubitus during the PA beam. Patients who have differences in thickness (separation) between the abdomen and head greater than 10cm undergo CT simulation in both left and right decubitus treatment positions. One plan for each CT is generated to evaluate dose to patient midline with both AP and PA fields, but only corresponding AP fields will be exported for treatment for patient left decubitus position and PA fields for patient right decubitus position. Subfields are added by collimating with the x-ray jaws according to separation changes at 5–7% steps to minimize hot regions to less than 10%. Finally, the monitor units (MUs) for the plans are verified with hand calculation and water phantom measurements. Results: Dose uniformity (+/−10%) is achieved with field-in-field using only asymmetric jaws. It is dosimetrically robust with respect to minor setup/patient variations inevitable due to patient conditions. MUs calculated with Pinnacle were verified in 3 clinical cases and only a 2% difference was found compared to homogeneous calculation. In-vivo dosimeters were also used to verify doses received by each patient with and confirmed dose variations less than 10%. Conclusion: We encountered several cases with separation differences that raised uniformity concerns — based on a 1% dose difference per cm separation difference assumption. This could Resultin an unintended hot spot, often in the head/neck, up to 25%. This method allows dose modulation without adding treatment complexity nor introducing radiobiological variations, providing a reasonable solution for this unique

  5. Signatures of large-scale magnetic fields in active galactic nuclei jets: transverse asymmetries

    NASA Astrophysics Data System (ADS)

    Clausen-Brown, E.; Lyutikov, M.; Kharb, P.

    2011-08-01

    We investigate the emission properties that a large-scale helical magnetic field imprints on active galactic nuclei (AGN) jet synchrotron radiation. A cylindrically symmetric relativistic jet and large-scale helical magnetic field produce significant asymmetrical features in transverse profiles of fractional linear polarization, intensity, the Faraday rotation and spectral index. The asymmetrical features of these transverse profiles correlate with one another in ways specified by the handedness of the helical field, the jet viewing angle (θob) and the bulk Lorentz factor of the flow (Γ). Thus, these correlations may be used to determine the structure of the magnetic field in the jet. In the case of radio galaxies (θob˜ 1 rad) and a subclass of blazars with particularly small viewing angles (θob≪ 1/Γ), we find an edge-brightened intensity profile that is similar to that observed in the radio galaxy M87. We present observations of the AGNs 3C 78 and NRAO 140 that display the type of transverse asymmetries that may be produced by large-scale helical magnetic fields.

  6. Constraining Large-Scale Solar Magnetic Field Models with Optical Coronal Observations

    NASA Astrophysics Data System (ADS)

    Uritsky, V. M.; Davila, J. M.; Jones, S. I.

    2015-12-01

    Scientific success of the Solar Probe Plus (SPP) and Solar Orbiter (SO) missions will depend to a large extent on the accuracy of the available coronal magnetic field models describing the connectivity of plasma disturbances in the inner heliosphere with their source regions. We argue that ground based and satellite coronagraph images can provide robust geometric constraints for the next generation of improved coronal magnetic field extrapolation models. In contrast to the previously proposed loop segmentation codes designed for detecting compact closed-field structures above solar active regions, we focus on the large-scale geometry of the open-field coronal regions located at significant radial distances from the solar surface. Details on the new feature detection algorithms will be presented. By applying the developed image processing methodology to high-resolution Mauna Loa Solar Observatory images, we perform an optimized 3D B-line tracing for a full Carrington rotation using the magnetic field extrapolation code presented in a companion talk by S.Jones at al. Tracing results are shown to be in a good qualitative agreement with the large-scalie configuration of the optical corona. Subsequent phases of the project and the related data products for SSP and SO missions as wwll as the supporting global heliospheric simulations will be discussed.

  7. Measurement of contact angles in a simulated microgravity environment generated by a large gradient magnetic field

    NASA Astrophysics Data System (ADS)

    Liu, Yong-Ming; Chen, Rui-Qing; Wu, Zi-Qing; Zhu, Jing; Shi, Jian-Yu; Lu, Hui-Meng; Shang, Peng; Yin, Da-Chuan

    2016-09-01

    The contact angle is an important parameter that is essential for studying interfacial phenomena. The contact angle can be measured using commercially available instruments. However, these well-developed instruments may not function or may be unsuitable for use in some special environments. A simulated microgravity generated by a large gradient magnetic field is such an environment in which the current measurement instruments cannot be installed. To measure the contact angle in this environment, new tools must be designed and manufactured to be compatible with the size and physical environment. In this study, we report the development and construction of a new setup that was specifically designed for use in a strong magnetic field to measure the contact angle between a levitated droplet and a solid surface. The application of the setup in a large gradient magnetic field was tested, and the contact angles were readily measured.

  8. Large Nc deconfinement transition in the presence of a magnetic field

    NASA Astrophysics Data System (ADS)

    Fraga, Eduardo S.; Noronha, Jorge; Palhares, Letícia F.

    2013-06-01

    We investigate the effect of a homogeneous magnetic field on the thermal deconfinement transition of QCD in the large Nc limit. First we discuss how the critical temperature decreases due to the inclusion of Nf≪Nc flavors of massless quarks in comparison to the pure glue case. Then we study the equivalent correction in the presence of an external Abelian magnetic field. To leading order in Nf/Nc, the deconfinement critical temperature decreases with the magnetic field if the flavor contribution to the pressure behaves paramagnetically, with a sufficiently large magnetization as to overcome any possible magnetic effects in the string tension. Finally, we discuss the effects from a finite quark mass and its competition with magnetic effects.

  9. Non-Gaussianity and large-scale structure in a two-field inflationary model

    SciTech Connect

    Tseliakhovich, Dmitriy; Hirata, Christopher

    2010-08-15

    Single-field inflationary models predict nearly Gaussian initial conditions, and hence a detection of non-Gaussianity would be a signature of the more complex inflationary scenarios. In this paper we study the effect on the cosmic microwave background and on large-scale structure from primordial non-Gaussianity in a two-field inflationary model in which both the inflaton and curvaton contribute to the density perturbations. We show that in addition to the previously described enhancement of the galaxy bias on large scales, this setup results in large-scale stochasticity. We provide joint constraints on the local non-Gaussianity parameter f-tilde{sub NL} and the ratio {xi} of the amplitude of primordial perturbations due to the inflaton and curvaton using WMAP and Sloan Digital Sky Survey data.

  10. Non-Gaussianity and Large Scale Structure in a two-field Inflationary model

    SciTech Connect

    Tseliakhovich, D.; Slosar, A.; Hirata, C.

    2010-08-30

    Single-field inflationary models predict nearly Gaussian initial conditions, and hence a detection of non-Gaussianity would be a signature of the more complex inflationary scenarios. In this paper we study the effect on the cosmic microwave background and on large-scale structure from primordial non-Gaussianity in a two-field inflationary model in which both the inflaton and curvaton contribute to the density perturbations. We show that in addition to the previously described enhancement of the galaxy bias on large scales, this setup results in large-scale stochasticity. We provide joint constraints on the local non-Gaussianity parameter f*{sub NL} and the ratio {zeta} of the amplitude of primordial perturbations due to the inflaton and curvaton using WMAP and Sloan Digital Sky Survey data.

  11. UNDERROAD BORING MACHINE OUTFIT, HORIZONTAL AUGER-TYPE, 8-, 12- AND 16-INCH PIPE CASING CAPACITY.

    DTIC Science & Technology

    Report covers the testing and evaluation of an underroad boring machine outfit for use by troops engaged in the installation of Military pipeline...the structural and mechanical stability of the boring machine and its accessories. Conclusions: (a) An underroad boring machine outfit similar to the...Military Standard as Class II and Class IV items of supply; (b) neither service nor environmental testing of the boring machine outfit is necessary; and (c

  12. 30 CFR 18.22 - Boring-type machines equipped for auxiliary face ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Boring-type machines equipped for auxiliary... AND ACCESSORIES Construction and Design Requirements § 18.22 Boring-type machines equipped for auxiliary face ventilation. Each boring-type continuous-mining machine that is submitted for approval...

  13. 30 CFR 18.22 - Boring-type machines equipped for auxiliary face ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Boring-type machines equipped for auxiliary... AND ACCESSORIES Construction and Design Requirements § 18.22 Boring-type machines equipped for auxiliary face ventilation. Each boring-type continuous-mining machine that is submitted for approval...

  14. 30 CFR 18.22 - Boring-type machines equipped for auxiliary face ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Boring-type machines equipped for auxiliary... AND ACCESSORIES Construction and Design Requirements § 18.22 Boring-type machines equipped for auxiliary face ventilation. Each boring-type continuous-mining machine that is submitted for approval...

  15. 30 CFR 18.22 - Boring-type machines equipped for auxiliary face ventilation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Boring-type machines equipped for auxiliary... AND ACCESSORIES Construction and Design Requirements § 18.22 Boring-type machines equipped for auxiliary face ventilation. Each boring-type continuous-mining machine that is submitted for approval...

  16. 30 CFR 18.22 - Boring-type machines equipped for auxiliary face ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Boring-type machines equipped for auxiliary... AND ACCESSORIES Construction and Design Requirements § 18.22 Boring-type machines equipped for auxiliary face ventilation. Each boring-type continuous-mining machine that is submitted for approval...

  17. UV absorption of the in-bore plasma emission from an EML using polycarbonate insulators

    SciTech Connect

    Clothiaux, E.J. . Dept. of Physics)

    1991-01-01

    This paper reports on the in-bore continuum emission spectrum, laced by absorption lines, observed to be completely cutoff for wavelengths shorter than about 3000 {Angstrom}. This cutoff wavelength is seen to occur at longer wavelengths as the plasma armature moves down the launcher bore. A mechanism for the absorption of shortwave radiation by ablated and evaporated bore materials is given.

  18. 46 CFR 148.04-13 - Ferrous metal borings, shavings, turnings, or cuttings (excluding stainless steel).

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Ferrous metal borings, shavings, turnings, or cuttings... Requirements for Certain Material § 148.04-13 Ferrous metal borings, shavings, turnings, or cuttings (excluding... described as ferrous metal borings, shavings, turnings, or cuttings on board vessels (excluding...

  19. On the Coexistence of a Radial Magnetic Field with the Large Scale Field in the Solar Corona

    NASA Astrophysics Data System (ADS)

    Habbal, S. R.; Woo, R.; Arnaud, J.

    2001-05-01

    Polarimetric measurements of the corona out to 2 Rs in the Fe XIII 10747 A line, the strongest of the iron forbidden lines, are placed for the first time in the context of spatially resolved images of coronal density structures. These measurements, which are the only tool currently available to yield the direction of the magnetic field, date to 1980, the only year when they were available with polarized brightness images of the corona. Through this comparison, the observed predominance of the radial component of the coronal magnetic field, discovered over three decades ago from eclipse observations, and established systematically by Arnaud (1982), is shown to point to the existence of two components of the coronal magnetic field: a non-radial component associated with the large scale structures known as streamers, and the second, more dominant one, a pervasive radial magnetic field. The coexistence of these two components provides new information for the distribution of open and closed magnetic flux in the solar corona.

  20. Large field-induced irreversibility in Ni-Mn based Heusler shape-memory alloys: A pulsed magnetic field study

    NASA Astrophysics Data System (ADS)

    Nayak, A. K.; Mejia, C. Salazar; D'Souza, S. W.; Chadov, S.; Skourski, Y.; Felser, C.; Nicklas, M.

    2014-12-01

    We present a pulsed magnetic field study on the magnetic and magnetostriction properties of Ni-Mn-Z (Z =In , Sn, and Sb) based Heusler shape-memory alloys. These materials generally display a field-induced magnetostructural transition that could lead to an irreversible phase transition, when measured near the martensitic transition temperature. Here, we show that independently of the transition temperature, the critical field for the phase transition sensitively depends on the main-group element in the sample. Irrespective of their compositions, all samples display a magnetization of around 2 μB/f .u . in the martensite phase and about 6 μB/f .u . in the cubic austenite phase. Our magnetic and magnetostriction measurements at low temperatures exhibit a partial or complete arrest of the high-field austenite phase below the reverse martensitic transition. This results in a large irreversibility with a hysteresis width as high as 24 T. We introduce a theoretical model to discuss the experimental results.

  1. Control of light trapping in a large atomic system by a static magnetic field

    NASA Astrophysics Data System (ADS)

    Skipetrov, S. E.; Sokolov, I. M.; Havey, M. D.

    2016-07-01

    We propose to control light trapping in a large ensemble of cold atoms by an external, static magnetic field. For an appropriate choice of frequency and polarization of the exciting pulse, the field is expected to speed up the fluorescence of a dilute atomic system. In a dense ensemble, the field does not affect the early-time superradiant signal but amplifies intensity oscillations at intermediate times and induces a very slow, nonexponential long-time decay. The slowing down of fluorescence is due to the excitation of spatially localized collective atomic states that appear only under a strong magnetic field and have exponentially long lifetimes. Our results therefore pave a way towards experimental observation of the disorder-induced localization of light in cold atomic systems.

  2. Tracking a large pseudostreamer to pinpoint the southern polar magnetic field reversal

    NASA Astrophysics Data System (ADS)

    Rachmeler, Laurel; Guennou, Chloé; Seaton, Daniel B.; Gibson, Sarah; Auchère, Frédéric

    2016-05-01

    The reversal of the solar polar magnetic field is notoriously hard to pin down due to the extreme viewing angle of the pole. In Cycle 24, the southern polar field reversal can be pinpointed with high accuracy due to a large-scale pseudostreamer that formed over the pole and persisted for approximately a year. We tracked the size and shape of this structure with multiple observations and analysis techniques including PROBA2/SWAP EUV images, AIA EUV images, CoMP data, and 3D tomographic reconstructions. We find that the heliospheric field reversed polarity in February 2014, whereas in the photosphere the last vestiges of the previous polar field polarity remained until March 2015.

  3. EFFECTS OF LARGE-SCALE NON-AXISYMMETRIC PERTURBATIONS IN THE MEAN-FIELD SOLAR DYNAMO

    SciTech Connect

    Pipin, V. V.; Kosovichev, A. G.

    2015-11-10

    We explore the response of a nonlinear non-axisymmetric mean-field solar dynamo model to shallow non-axisymmetric perturbations. After a relaxation period, the amplitude of the non-axisymmetric field depends on the initial condition, helicity conservation, and the depth of perturbation. It is found that a perturbation that is anchored at 0.9 R{sub ⊙} has a profound effect on the dynamo process, producing a transient magnetic cycle of the axisymmetric magnetic field, if it is initiated at the growing phase of the cycle. The non-symmetric, with respect to the equator, perturbation results in a hemispheric asymmetry of the magnetic activity. The evolution of the axisymmetric and non-axisymmetric fields depends on the turbulent magnetic Reynolds number R{sub m}. In the range of R{sub m} = 10{sup 4}–10{sup 6} the evolution returns to the normal course in the next cycle, in which the non-axisymmetric field is generated due to a nonlinear α-effect and magnetic buoyancy. In the stationary state, the large-scale magnetic field demonstrates a phenomenon of “active longitudes” with cyclic 180° “flip-flop” changes of the large-scale magnetic field orientation. The flip-flop effect is known from observations of solar and stellar magnetic cycles. However, this effect disappears in the model, which includes the meridional circulation pattern determined by helioseismology. The rotation rate of the non-axisymmetric field components varies during the relaxation period and carries important information about the dynamo process.

  4. Real-time distortion correction system of large-field optical display equipment based on FPGA

    NASA Astrophysics Data System (ADS)

    Zheng, Chun; Zhou, Yongjun; Zheng, Yongrui; Li, Jie

    2011-08-01

    Current distortion correction systems can not meet the requirements of the large-field optical display equipment because of small field, low resolution, poor real-time property and commonality. "The symmetrical transform" and "the improved bilinear interpolation" were proposed. The general system scheme was designed and implemented in the Virtex-5 FPGA devices. The appropriate data structure of the look-up table was adopted and the optimized scheme for the input memory named "the double even-odd cache" was put forward. MIG (Memory Interface Generator) software tool was utilized to control DDR2 SDRAM and DSP48E was used. The real-time distortion correction system of the large-field optical display equipment was accomplished. The experimental result shows that the correction system can correct the large-field and high-resolution (1280x1024) video image (60 frames per second). The system delays only 1.48ms while the deviation in precision is less than 9' and has the well commonality.

  5. Large field-of-view range-gated laser imaging based on image fusion

    NASA Astrophysics Data System (ADS)

    Ren, Pengdao; Wang, Xinwei; Sun, Liang; You, Ruirong; Lei, Pingshun; Zhou, Yan

    2016-11-01

    Laser range-gated imaging has great potentials in remote night surveillance with far detection distance and high resolution, even if under bad weather conditions such as fog, snow and rain. However, the field of view (FOV) is smaller than large objects like buildings, towers and mountains, thus only parts of targets are observed in one single frame, so that it is difficult for targets identification. Apparently, large FOV is beneficial to solve the problem, but the detection range is not available due to low illumination density in a large field of illumination matching with the FOV. Therefore, a large field-of-view range-gated laser imaging is proposed based on image fusion in this paper. Especially an image fusion algorithm has been developed for low contrast images. First of all, an infrared laser range-gated system is established to acquire gate images with small FOV for three different scenarios at night. Then the proposed image fusion algorithm is used for generating panoramas for the three groups of images respectively. Compared with raw images directly obtained by the imaging system, the fused images have a larger FOV with more detail target information. The experimental results demonstrate that the proposed image fusion algorithm is effective to expand the FOV of range-gated imaging.

  6. Large Field of View Particle-Image Velocimetry (LF-PIV): Design and Performance

    NASA Astrophysics Data System (ADS)

    Pol, Suhas; Hoffman, John; Balasubramaniam, Balakumar; P-23, LANL Team

    2011-11-01

    We discuss the challenges and limitations associated with the development of a Large Field of View Particle Image Velocimetry (LF-PIV) diagnostic that is capable of resolving large scale motions (3m x 1m per camera) in gas phase laboratory experiments. While this diagnostic is developed for the measurement of wakes and local inflow conditions around research wind turbines, the design considerations provided here are also relevant for the application of LF-PIV to atmospheric boundary layer, rotorcraft dynamics and large-scale wind tunnel flows. Scaling laws associated with LF-PIV systems are presented along with the performance analysis of low-density, large diameter Expancel particles that appear to be promising candidates for LF-PIV seeding. Comparison of data obtained by LF-PIV measurements (2MP camera) and regular format sized PIV measurements show an agreement of within 1% for mean velocity and 8% for turbulent statistics respectively. Los Alamos National Laboratory, NM, USA.

  7. Statistical relationship between large-scale upward field-aligned currents and electron precipitation

    NASA Astrophysics Data System (ADS)

    Korth, Haje; Zhang, Yongliang; Anderson, Brian J.; Sotirelis, Thomas; Waters, Colin L.

    2014-08-01

    Simultaneous observations of Birkeland currents by the constellation of Iridium satellites and N2 Lyman-Birge-Hopfield (LBH) auroral emissions measured by the Global Ultraviolet Imager (GUVI) onboard the Thermosphere, Ionosphere, and Mesosphere Energetics and Dynamics (TIMED) satellite are used to establish relationships between large-scale upward field-aligned currents and electron precipitation during stable current configurations. The electron precipitation was inferred from GUVI data using a statistical relationship between LBH intensity and electron energy flux. LBH emissions with >5% contribution from protons, identified by Lyman-alpha intensity, were excluded from the analysis. The Birkeland currents were derived with a spatial resolution of 3° in latitude and 2 h in local time. For southward interplanetary magnetic field (IMF), the electron precipitation occurred primarily within and near large-scale upward currents. The correspondence was less evident for northward IMF, presumably because the spatial variability is large compared to the areas of interest so that the number of events identified is smaller and the derived statistical distributions are less reliable. At dusk, the correlation between upward current and precipitation was especially high, where a larger fraction of the electron precipitation is accelerated downward by a field-aligned potential difference. Unaccelerated electron precipitation dominated in the morning sector, presumably induced by scattering of eastward-drifting energetic electrons into the loss cone through interaction with whistler-mode waves (diffuse precipitation) rather than by field-aligned acceleration. In the upward Region 1 on the dayside, where the electron precipitation is almost exclusively due to field-aligned acceleration, a quadratic relationship between current density and electron energy flux was observed, implying a linear current-voltage relationship in this region. Current density and electron energy flux in

  8. Universality of sparse d > 2 conformal field theory at large N

    NASA Astrophysics Data System (ADS)

    Belin, Alexandre; de Boer, Jan; Kruthoff, Jorrit; Michel, Ben; Shaghoulian, Edgar; Shyani, Milind

    2017-03-01

    We derive necessary and sufficient conditions for large N conformal field theories to have a universal free energy and an extended range of validity of the higher-dimensional Cardy formula. These constraints are much tighter than in two dimensions and must be satisfied by any conformal field theory dual to Einstein gravity. We construct and analyze symmetric product orbifold theories on T^d and show that they only realize the necessary phase structure and extended range of validity if the seed theory is assumed to have a universal vacuum energy.

  9. Field Test Results of Automated Demand Response in a Large Office Building

    SciTech Connect

    Han, Junqiao; Piette, Mary Ann; Kiliccote, Sila

    2008-10-20

    Demand response (DR) is an emerging research field and an effective tool that improves grid reliability and prevents the price of electricity from rising, especially in deregulated markets. This paper introduces the definition of DR and Automated Demand Response (Auto-DR). It describes the Auto-DR technology utilized at a commercial building in the summer of 2006 and the methodologies to evaluate associated demand savings. On the basis of field tests in a large office building, Auto-DR is proven to be a reliable and credible resource that ensures a stable and economical operation of the power grid.

  10. A photonic-crystal optical antenna for extremely large local-field enhancement.

    PubMed

    Chang, Hyun-Joo; Kim, Se-Heon; Lee, Yong-Hee; Kartalov, Emil P; Scherer, Axel

    2010-11-08

    We propose a novel design of an all-dielectric optical antenna based on photonic-band-gap confinement. Specifically, we have engineered the photonic-crystal dipole mode to have broad spectral response (Q~70) and well-directed vertical-radiation by introducing a plane mirror below the cavity. Considerably large local electric-field intensity enhancement~4,500 is expected from the proposed design for a normally incident planewave. Furthermore, an analytic model developed based on coupled-mode theory predicts that the electric-field intensity enhancement can easily be over 100,000 by employing reasonably high-Q (~10,000) resonators.

  11. Development and field trial of a FBG-based magnetic sensor for large hydrogenerators

    NASA Astrophysics Data System (ADS)

    Fracarolli, João. P. V.; Rosolem, João. B.; Tomiyama, Elias K.; Floridia, Claudio; Penze, Rivael S.; Peres, Rodrigo; Dini, Danilo C.; Hortencio, Claudio A.; Dilli, Paulo I. G.; da Silva, Erlon V.; dos Santos, Marcéu. C.; Fruett, Fabiano

    2016-05-01

    We propose a passive optical sensor for online magnetic field monitoring in large hydrogenerators, based on FBG (Fiber Bragg Grating) technology and a magnestostrictive material (Terfenol-D). The objective of this sensor is to detect faults in the rotor windings due to inter turn short-circuits. This device is packaged in a novel rod-shaped enclosure, allowing it to be easily installed on the ventilation ducts of the stator of the machine. This sensor was developed and tested in laboratory and it has been evaluated in a field test on a 200 MVA, 60 poles hydrogenerator.

  12. Large-scale electric fields resulting from magnetic reconnection in the corona

    NASA Technical Reports Server (NTRS)

    Kopp, R. A.; Poletto, G.

    1986-01-01

    The method of Forbes and Priest (2-D model) is applied to the large two-ribbon flare of July 29, 1973, for which both detailed H observations and magnetic data are available. For this flare the ribbons were long, nearly straight, and parallel to each other, and the 2-D model for the coronal field geometry may be adequate. The temporal profile E(t) is calculated and indicates that reconnection sets in at the beginning of the decay phase. From this time the electric field grows rapidly to a maximum value of about 2 V/cm within just a few minutes. Thereafter it decreases monotonically with time.

  13. Mechanisation of large-scale agricultural fields in developing countries - a review.

    PubMed

    Onwude, Daniel I; Abdulstter, Rafia; Gomes, Chandima; Hashim, Norhashila

    2016-09-01

    Mechanisation of large-scale agricultural fields often requires the application of modern technologies such as mechanical power, automation, control and robotics. These technologies are generally associated with relatively well developed economies. The application of these technologies in some developing countries in Africa and Asia is limited by factors such as technology compatibility with the environment, availability of resources to facilitate the technology adoption, cost of technology purchase, government policies, adequacy of technology and appropriateness in addressing the needs of the population. As a result, many of the available resources have been used inadequately by farmers, who continue to rely mostly on conventional means of agricultural production, using traditional tools and equipment in most cases. This has led to low productivity and high cost of production among others. Therefore this paper attempts to evaluate the application of present day technology and its limitations to the advancement of large-scale mechanisation in developing countries of Africa and Asia. Particular emphasis is given to a general understanding of the various levels of mechanisation, present day technology, its management and application to large-scale agricultural fields. This review also focuses on/gives emphasis to future outlook that will enable a gradual, evolutionary and sustainable technological change. The study concludes that large-scale-agricultural farm mechanisation for sustainable food production in Africa and Asia must be anchored on a coherent strategy based on the actual needs and priorities of the large-scale farmers. © 2016 Society of Chemical Industry.

  14. Large-angle and high-efficiency tunable phase grating using fringe field switching liquid crystal.

    PubMed

    Xu, Daming; Tan, Guanjun; Wu, Shin-Tson

    2015-05-04

    We propose a switchable phase grating using fringe field switching (FFS) cells. The FFS phase grating possesses several attractive features: large diffraction angle, high diffraction efficiency, fast response time, and high contrast ratio. It can diffract >32% light to ± 2nd orders with a large diffraction angle of 12.1°. Meanwhile, its response time remains relatively fast even at -40°C. A simulation model is developed to explain the experimental results and good agreement is obtained. We also demonstrate a blazed phase grating to achieve tunable beam steering between 0th, 1st and 2nd orders.

  15. Large Eddy Simulation and Field Experiments of Pollen Transport in the Atmospheric Boundary Layer

    NASA Astrophysics Data System (ADS)

    Chamecki, M.; Meneveau, C.; Parlange, M. B.; van Hout, R.

    2006-12-01

    Dispersion of airborne pollen by the wind has been a subject of interest for botanists and allergists for a long time. More recently, the development of genetically modified crops and questions about cross-pollination and subsequent contamination of natural plant populations has brought even more interest to this field. A critical question is how far from the source field pollen grains will be advected. Clearly the answer depends on the aerodynamic properties of the pollen, geometrical properties of the field, topography, local vegetation, wind conditions, atmospheric stability, etc. As a consequence, field experiments are well suited to provide some information on pollen transport mechanisms but are limited to specific field and weather conditions. Numerical simulations do not have this drawback and can be a useful tool to study pollen dispersal in a variety of configurations. It is well known that the dispersion of particles in turbulent fields is strongly affected by the large scale coherent structures. Large Eddy Simulation (LES) is a technique that allows us to study the typical distances reached by pollen grains and, at the same time, resolve the larger coherent structures present in the atmospheric boundary layer. The main objective of this work is to simulate the dispersal of pollen grains in the atmospheric surface layer using LES. Pollen concentrations are simulated by an advection-diffusion equation including gravitational settling. Of extreme importance is the specification of the bottom boundary conditions characterizing the pollen source over the canopy and the deposition process everywhere else. In both cases we make use of the theoretical profile for suspended particles derived by Kind (1992). Field experiments were performed to study the applicability of the theoretical profile to pollen grains and the results are encouraging. Airborne concentrations as well as ground deposition from the simulations are compared to experimental data to validate the

  16. A bi-axial active boring tool for chatter mitigation

    SciTech Connect

    Redmond, J.M.; Barney, P.S.

    1998-08-01

    This paper summarizes results of metal cutting tests using an actively damped boring bar to suppress regenerative chatter. PZT stack actuators were integrated into a commercially available two-inch diameter boring bar to suppress bending vibrations. Since the modified tool requires no specialized mounting hardware, it can be readily mounted on a variety of machines. A cutting test using the prototype bar to remove metal from a hardened steel workpiece verifies that the authors actively damped tool yields significant vibration reduction and improved surface finish as compared to the open-loop case. In addition, the overall performance of the prototype bar is compared to that of an unmodified bar of pristine geometry, revealing that a significant enlargement of the stable machining envelope is obtained through application of feedback control.

  17. Frac height may increase away from well bore

    SciTech Connect

    Hunt, E. )

    1991-02-25

    Well logs with deep investigation capabilities are necessary to determine accurately the height of hydraulically produced fractures. Logs with shallow investigation capability will indicate the height of the fracture near the well bore, but as shown in a test in an East Texas well, fracture height in some formations can be substantially greater away from the well bore. In the East Texas test, six wire line surveys were run, including the usual gamma ray surveys. The fracture heights determined by the above logs are plotted. The independent estimates of gross fracture height varied considerably. Four logs, TWRL, VDL, SCAN, and CEL appear to be influenced by the fracture. Results were inconclusive from the Au and the CBL log. Analysis of each of these indicates a different minimum fracture height in this well.

  18. Mixed metal hydroxide drilling fluid minimizes well bore washouts

    SciTech Connect

    Lavoix, F. ); Lewis, M. )

    1992-09-28

    This paper reports that the use of a mixed metal hydroxide (MMH) drilling fluid, instead of a conventional polymer-based fluid, improved well bore stability in troublesome formations in West Africa. The unique flow and suspension characteristics of the MMH fluid improved cuttings removal and decreased well bore washouts. With fewer hole problems and better cleaning in the well, the operator reduced drilling time and cost of the well. MMH compounds were developed and introduced to the drilling industry a few years ago. Initially their utility was limited by an inability to achieve reliable filtration control without destroying the unique fluid rheology. A fully functional drilling fluid system, based on this unusual line of chemistry, has been developed and used with great success in dozens of wells around the world.

  19. Sub-slab pressure field extension in schools and other large buildings

    NASA Astrophysics Data System (ADS)

    Harris, D. B.; Craig, A. B.; Leovic, K. W.

    1991-09-01

    The experiences of EPA are discussed in using pressure field extension (PFE) to design active subslab depressurization (ASD) systems to reduce radon levels in old and new schools, including instances where the data collected resulted in the installation of smaller systems than expected and selection of high vacuum fans instead of normal mitigation fans. A central collection system for use under very large slabs is discussed and PFE data are given for a hospital under construction. The most direct method of projecting or measuring the performance of an ASD system is to measure the strength and extent of the pressure field established under the slab. The PFE can be determined (during diagnostics) to help design an ASD system and (following installation) to ascertain system performance. In schools and other large buildings, these data are invaluable to provide a system that will mitigate the building without undue cost escalation.

  20. Development of a Large Field of View Shadowgraph System for a 16 Ft. Transonic Wind Tunnel

    NASA Technical Reports Server (NTRS)

    Talley, Michael A.; Jones, Stephen B.; Goodman, Wesley L.

    2000-01-01

    A large field of view shadowgraph flow visualization system for the Langley 16 ft. Transonic Tunnel (16 ft.TT) has been developed to provide fast, low cost, aerodynamic design concept evaluation capability to support the development of the next generation of commercial and military aircraft and space launch vehicles. Key features of the 16 ft. TT shadowgraph system are: (1) high resolution (1280 X 1024) digital snap shots and sequences; (2) video recording of shadowgraph at 30 frames per second; (3) pan, tilt, & zoom to find and observe flow features; (4) one microsecond flash for freeze frame images; (5) large field of view approximately 12 X 6 ft; and (6) a low maintenance, high signal/noise ratio, retro-reflective screen to allow shadowgraph imaging while test section lights are on.

  1. Large-scale peculiar velocity field in flat models of the universe

    SciTech Connect

    Vittorio, N.; Turner, M.S.

    1987-05-01

    The inflationary universe scenario predicts a flat universe and both adiabatic and isocurvature primordial density perturbations with the Zel'dovich spectrum. The two simplest realizations, models dominated by hot or cold dark matter, seem to be in conflict with observations. Flat models with two components of mass density, where one of the components of mass density is smoothly distributed, are examined, and the large-scale peculiar velocity field for these models is computed. For the smooth component the authors consider relativistic particles, a relic cosmological term, and light strings. At present the observational situation is unsettled, but, in principle, the large-scale peculiar velocity field is a very powerful discriminator between these different models. 66 references.

  2. Safety and immunogenicity of the synthetic malaria vaccine SPf66 in a large field trial.

    PubMed

    Amador, R; Moreno, A; Murillo, L A; Sierra, O; Saavedra, D; Rojas, M; Mora, A L; Rocha, C L; Alvarado, F; Falla, J C

    1992-07-01

    In the first field trial with synthetic malaria vaccine SPf66 in a large population naturally exposed to malaria, 9957 persons greater than 1 year old and residing on the Colombian Pacific coast received three doses of the vaccine. To evaluate vaccine safety, clinical observations were made 30 min and 48 h after each immunization. There were no adverse reactions in 95.7% of cases. In the 4.3% of cases with adverse reactions, local induration and erythema were the most frequent. In a randomly selected group of vaccinees, anti-SPf66 antibody titers were measured after the third dose: 93% of the vaccinees raised antibodies to SPf66. Among these, 55% had titers greater than 1:1600. These results demonstrate the safety and immunogenicity of the SPf66 vaccine in a large field trial.

  3. Large photon drag effect of intrinsic graphene induced by plasmonic evanescent field

    NASA Astrophysics Data System (ADS)

    Luo, Ma; Li, Zhibing

    2016-12-01

    A large photon drag effect of the massless Dirac fermions in intrinsic graphene is predicted for a graphene-on-plasmonic-layer system. The surface plasmons in the plasmonic layer enlarge the wave number of the photon hundreds times more than in vacuum. The evanescent field of the surface plasmons generates a directional motion of carriers in the intrinsic graphene because of the large momentum transfer from the surface plasmon to the excited carriers. A model Hamiltonian is developed on the assumption that the in-plane wavelength of the surface plasmons is much smaller than the mean free path of the carriers. The time evolution of the density matrix is solved by perturbation method as well as numerical integration. The nondiagonal density matrix elements with momentum transfer lead to a gauge current, which is an optically driven macroscopic direct current. The dependence of the macroscopic direct current on the incident direction and intensity of the laser field is studied.

  4. Fossils from bore holes on the Eastern Shore Peninsula, Virginia

    USGS Publications Warehouse

    Todd, Ruth; Gardner, Julia A.; Sohn, I.G.

    1955-01-01

    This report lists Foraminifera, Mollusca, and Ostracoda in five bore holes that penetrated a maximum of 445 feet of section in sediments of Pleistocene and Miocene age, and discusses the paleoecologic and stratigraphic significance of the fossils. It includes the contents of references 6, 16, and 18 of Virginia Division of Geology Mineral Resources Circular No. 2, dealing with the geology and groundwater resources of the Eastern Shore peninsula.

  5. Self-Boring Pressuremeter in Pluvially Deposited Sands.

    DTIC Science & Technology

    1987-06-01

    OF TABLES TABLE 1: SUMMARY OF INSTALLATION CONDITIONS DURING SELF-BORING TABLE 2: SUMMARY OF GENERAL CALIBRATION CHAMBER CONDITIONS AFTER SAMPLE...CANKOMETER MARK VIII FIG. 4: GENERAL CHARACTERISTICS OF TICINO AND HOKKSUND SAND FIG. 5: SCHEMATIC OUTLINE OF SAND SPREADER FIG. 6: SCHEMATIC OUTLINE...COMPARISON OF CALCULATED #Ps ROM SBPT AND EQUIVALENT O FROM TRIAXIAL TESTS 04 LIST OF APPENDIXES APP. I : EXAMPLE OF COMPUTER GENERATED PLOTS FOR

  6. Active chatter control system for long-overhang boring bars

    NASA Astrophysics Data System (ADS)

    Browning, Douglas R.; Golioto, Igor; Thompson, Norman B.

    1997-05-01

    Some machining processes, such as boring, have been historically limited by excessive bar vibration, often resulting in poor surface finish and reduced tool life. A unique boring bar system has been developed to suppress bar vibration, or chatter, during machining using active control technology. Metal cutting test programs have shown proven, repeatable performance on hard-to-cut, aircraft industry high-temperature nickel alloys as well as more easily cut carbon steels. Critical bar length-to-diameter (L/D) ratios, depths-of-cuts, feed rates and cutting speeds far exceed those attainable from the best available passively-damped boring bars. This industry-ready system consists of three principle subsystems: active clamp, instrumented bar, and control electronics. The active clamp is a lathe-mountable body capable of supporting bars of varying sizes and articulating them in orthogonal directions from the base of the bar shank. The instrumented bar consists of a steel shank, standard insert head and imbedded accelerometers. Wire harnesses from both the bar and clamp connect to control electronics comprised of highly-efficient switched- capacitor amplifiers that drive the piezoelectric actuators, sensor signal conditioning, a PC-based program manager and two 32-bit floating-point DSPs. The program manager code runs on the host PC and distributes system identification and control functions to the two DSPs. All real-time signal processing is based on the principles of adaptive filter minimization. For the described system, cutting performance has extended existing chatter thresholds (cutting parameter combinations) for nickel alloys by as much as 400% while maintaining precision surface finish on the machined part. Bar L/D ratios as high as 11 have enabled deep boring operations on nickel workpieces that otherwise could not be performed free of chatter.

  7. [Irradiation of lymphogranulomatosis patients with large fields of complex configuration, calculating absorbed doses by microcomputer].

    PubMed

    Belyĭ, E K; Miasnikov, A A; Mendeleev, I M

    1985-01-01

    The authors demonstrated advantages of irradiating lymphogranulomatosis patients with large fields of complex configuration. The use of computer eliminates the difficulties of dosage calculation. Application for these purposes of the 15 VUMS-28 unit based on the microcomputer "Elektronika-60" is suggested. Algorithm of the dosage calculation program is presented. The program is drawn up according to the GOST so that it can be used by other institutions concerned.

  8. Estimating field-of-view loss in bathymetric lidar: application to large-scale simulations.

    PubMed

    Carr, Domenic; Tuell, Grady

    2014-07-20

    When designing a bathymetric lidar, it is important to study simulated waveforms for various combinations of system and environmental parameters. To predict a system's ranging accuracy, it is often necessary to analyze thousands of waveforms. In these large-scale simulations, estimating field-of-view loss is a challenge because the calculation is complex and computationally intensive. This paper describes a new procedure for quickly approximating this loss, and illustrates how it can be used to efficiently predict ranging accuracy.

  9. LUMINOUS RED GALAXY HALO DENSITY FIELD RECONSTRUCTION AND APPLICATION TO LARGE-SCALE STRUCTURE MEASUREMENTS

    SciTech Connect

    Reid, Beth A.; Spergel, David N.; Bode, Paul E-mail: dns@astro.princeton.edu

    2009-09-01

    The nontrivial relationship between observations of galaxy positions in redshift space and the underlying matter field complicates our ability to determine the linear theory power spectrum and extract cosmological information from galaxy surveys. The Sloan Digital Sky Survey (SDSS) luminous red galaxy (LRG) catalog has the potential to place powerful constraints on cosmological parameters. LRGs are bright, highly biased tracers of large-scale structure. However, because they are highly biased, the nonlinear contribution of satellite galaxies to the galaxy power spectrum is large and fingers-of-God (FOGs) are significant. The combination of these effects leads to a {approx}10% correction in the underlying power spectrum at k = 0.1 h Mpc{sup -1} and {approx}40% correction at k = 0.2 h Mpc{sup -1} in the LRG P(k) analysis of Tegmark et al., thereby compromising the cosmological constraints when this potentially large correction is left as a free parameter. We propose an alternative approach to recovering the matter field from galaxy observations. Our approach is to use halos rather than galaxies to trace the underlying mass distribution. We identify FOGs and replace each FOG with a single halo object. This removes the nonlinear contribution of satellite galaxies, the one-halo term. We test our method on a large set of high-fidelity mock SDSS LRG catalogs and find that the power spectrum of the reconstructed halo density field deviates from the underlying matter power spectrum at the {<=}1% level for k {<=} 0.1 h Mpc{sup -1} and {<=}4% at k = 0.2 h Mpc{sup -1}. The reconstructed halo density field also removes the bias in the measurement of the redshift space distortion parameter {beta} induced by the FOG smearing of the linear redshift space distortions.

  10. Statistics on the parameters of nonisothermal ionospheric plasma in large mesospheric electric fields

    NASA Astrophysics Data System (ADS)

    Martynenko, S.; Rozumenko, V.; Tyrnov, O.; Manson, A.; Meek, C.

    The large V/m electric fields inherent in the mesosphere play an essential role in lower ionospheric electrodynamics. They must be the cause of large variations in the electron temperature and the electron collision frequency at D region altitudes, and consequently the ionospheric plasma in the lower part of the D region undergoes a transition into a nonisothermal state. This study is based on the databases on large mesospheric electric fields collected with the 2.2-MHz radar of the Institute of Space and Atmospheric Studies, University of Saskatchewan, Canada (52°N geographic latitude, 60.4°N geomagnetic latitude) and with the 2.3-MHz radar of the Kharkiv V. Karazin National University (49.6°N geographic latitude, 45.6°N geomagnetic latitude). The statistical analysis of these data is presented in Meek, C. E., A. H. Manson, S. I. Martynenko, V. T. Rozumenko, O. F. Tyrnov, Remote sensing of mesospheric electric fields using MF radars, Journal of Atmospheric and Solar-Terrestrial Physics, in press. The large mesospheric electric fields is experimentally established to follow a Rayleigh distribution in the interval 0

  11. Characterization of large size YBa2Cu3O7-δ films using magnetic field penetration

    NASA Astrophysics Data System (ADS)

    Almog, B.; Azoulay, M.; Castro, H.; Deutscher, G.

    2005-11-01

    High critical current density (jc) is one of the most important properties of high Tc superconducting thin films. Determining it is difficult especially in large films (2-3 inch). We propose a non-destructive and easy technique for measuring jc. From measurements of the magnetic moment in the middle of a superconducting film as a function of the external magnetic field, we calculate the macroscopic critical current density.

  12. Phase retrieval from a single near-field diffraction pattern with a large Fresnel number.

    PubMed

    Li, Enrong; Liu, Yijin; Liu, Xiaosong; Zhang, Kai; Wang, Zhili; Hong, Youli; Yuan, Qingxi; Huang, Wanxia; Marcelli, Augusto; Zhu, Peiping; Wu, Ziyu

    2008-11-01

    A new method of phase retrieval from a single near-field diffraction image with a large Fresnel number is presented and discussed. This method requires only the oversampled diffraction pattern without any other information such as the object envelope. Moreover, we show that the combination with a fast computational method is possible when the linear oversampling ratio is an integer. Numerical simulations are also presented, showing that the method works well with noisy data.

  13. Anisotropic heat diffusion on stochastic magnetic field in the Large Helical Device

    NASA Astrophysics Data System (ADS)

    Suzuki, Yasuhiro

    2016-10-01

    The magnetic topology is a key issue in fusion plasma researches. An example is the Resonant Magnetic Perturbation (RMP) to control the transport and MHD activities in tokamak and stellarator experiments. However, the physics how the RMP affects the transport and MHD is not clear. One reason is a role of the magnetic topology is unclear. That problem is connecting to the identification of the magnetic topology in the experiment. In the experiment, the finite temperature gradient is observed on the stochastic field where is stochastized by the theoretical prediction. In a classical theory, the electron temperature gradient should be zero on the stochastic magnetic field. We need to study the stochastic magnetic field can keep the finite temperature gradient or not. In this study, we study the anisotropic heat diffusion equation to simulate the heat transport on the stochastic magnetic field. Changing a ratio of κ∥ and κ⊥, the distribution of the temperature on the stochastic magnetic field is obtained. Hudson et al. pointed out the KAM surface is a barrier to keep the finite temperature. We simulate those results in realistic magnetic field of the Large Helical Device.

  14. A PILOT FOR A VERY LARGE ARRAY H I DEEP FIELD

    SciTech Connect

    Fernandez, Ximena; Van Gorkom, J. H.; Schiminovich, David; Hess, Kelley M.; Pisano, D. J.; Kreckel, Kathryn; Momjian, Emmanuel; Popping, Attila; Oosterloo, Tom; Chomiuk, Laura; Verheijen, M. A. W.; Henning, Patricia A.; Bershady, Matthew A.; Wilcots, Eric M.; Scoville, Nick

    2013-06-20

    High-resolution 21 cm H I deep fields provide spatially and kinematically resolved images of neutral hydrogen at different redshifts, which are key to understanding galaxy evolution across cosmic time and testing predictions of cosmological simulations. Here we present results from a pilot for an H I deep field done with the Karl G. Jansky Very Large Array (VLA). We take advantage of the newly expanded capabilities of the telescope to probe the redshift interval 0 < z < 0.193 in one observation. We observe the COSMOS field for 50 hr, which contains 413 galaxies with optical spectroscopic redshifts in the imaged field of 34' Multiplication-Sign 34' and the observed redshift interval. We have detected neutral hydrogen gas in 33 galaxies in different environments spanning the probed redshift range, including three without a previously known spectroscopic redshift. The detections have a range of H I and stellar masses, indicating the diversity of galaxies we are probing. We discuss the observations, data reduction, results, and highlight interesting detections. We find that the VLA's B-array is the ideal configuration for H I deep fields since its long spacings mitigate radio frequency interference. This pilot shows that the VLA is ready to carry out such a survey, and serves as a test for future H I deep fields planned with other Square Kilometer Array pathfinders.

  15. Indirect interband transition induced by optical near fields with large wave numbers

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Maiku; Nobusada, Katsuyuki

    2016-05-01

    Optical near fields (ONFs) have Fourier components with large wave numbers that are two or three orders of magnitude larger than those of far-field propagating light owing to their nonuniformity in space. By utilizing these large wave numbers, the ONF is expected to induce an indirect interband transition between Bloch states having different wave numbers and directly generate an electron-hole pair without electron-phonon coupling. We perform time-dependent dynamics calculations of a one-dimensional periodic potential with an indirect band-gap structure and demonstrate that the ONF definitely induces an indirect interband transition. Instead of using the general Bloch boundary condition, which is usually imposed in conventional band structure calculations, we adopt an alternative boundary condition, the Born-von Kármán boundary condition, to appropriately treat indirect interband transitions. The calculated absorption spectra for the far-field and ONF excitations show different absorption edges and spectral patterns. We argue that this difference can be experimentally measured as evidence of the effects of the large wave numbers of the ONF.

  16. Design of apochromatic lens with large field and high definition for machine vision.

    PubMed

    Yang, Ao; Gao, Xingyu; Li, Mingfeng

    2016-08-01

    Precise machine vision detection for a large object at a finite working distance (WD) requires that the lens has a high resolution for a large field of view (FOV). In this case, the effect of a secondary spectrum on image quality is not negligible. According to the detection requirements, a high resolution apochromatic objective is designed and analyzed. The initial optical structure (IOS) is combined with three segments. Next, the secondary spectrum of the IOS is corrected by replacing glasses using the dispersion vector analysis method based on the Buchdahl dispersion equation. Other aberrations are optimized by the commercial optical design software ZEMAX by properly choosing the optimization function operands. The optimized optical structure (OOS) has an f-number (F/#) of 3.08, a FOV of φ60  mm, a WD of 240 mm, and a modulated transfer function (MTF) of all fields of more than 0.1 at 320  cycles/mm. The design requirements for a nonfluorite material apochromatic objective lens with a large field and high definition for machine vision detection have been achieved.

  17. Infrared-temperature variability in a large agricultural field. [Dunnigan, California

    NASA Technical Reports Server (NTRS)

    Millard, J. P.; Goettelman, R. C.; Leroy, M. L. (Principal Investigator)

    1980-01-01

    The combined effect of water carved gullies, varying soil color, moisture state of the soil and crop, nonuniform phenology, and bare spots was measured for commercially grown barley planted on varying terrain. For all but the most rugged terrain, over 80% of the area within 4, 16, 65, and 259 ha cells was at temperatures within 3 C of the mean cell temperature. The result of using relatively small, 4 ha instantaneous field of views for remote sensing applications is that either the worst or the best of conditions is often observed. There appears to be no great advantage in utilizing a small instantaneous field of view instead of a large one for remote sensing of crop canopy temperatures. The two alternatives for design purposes are then either a very high spatial resolution, of the order of a meter or so, where the field is very accurately temperature mapped, or a low resolution, where the actual size seems to make little difference.

  18. Effective realization of random magnetic fields in compounds with large single-ion anisotropy

    NASA Astrophysics Data System (ADS)

    Herbrych, J.; Kokalj, J.

    2017-03-01

    We show that spin S =1 system with large and random single-ion anisotropy can be at low energies mapped to a S =1 /2 system with random magnetic fields. This is, for example, realized in Ni (Cl1 -xBrx)2-4 SC (NH2)2 compound (DTNX) and therefore it represents a long-sought realization of random local (on-site) magnetic fields in antiferromagnetic systems. We support the mapping by numerical study of S =1 and effective S =1 /2 anisotropic Heisenberg chains and find excellent agreement for static quantities and also for the spin conductivity. Such systems can therefore be used to study the effects of local random magnetic fields on transport properties.

  19. Lipid membranes in external electric fields: kinetics of large pore formation causing rupture.

    PubMed

    Winterhalter, Mathias

    2014-06-01

    About 40 years ago, Helfrich introduced an elastic model to explain shapes and shape transitions of cells (Z Naturforsch C, 1973; 28:693). This seminal article stimulated numerous theoretical as well as experimental investigations and created new research fields. In particular, the predictive power of his approach was demonstrated in a large variety of lipid model system. Here in this review, we focus on the development with respect to planar lipid membranes in external electric fields. Stimulated by the early work of Helfrich on electric field forces acting on liposomes, we extended his early approach to understand the kinetics of lipid membrane rupture. First, we revisit the main forces determining the kinetics of membrane rupture followed by an overview on various experiments. Knowledge on the kinetics of defect formation may help to design stable membranes or serve for novel mechanism for controlled release.

  20. Mantle convection and the large scale structures of the Earth's gravitational field

    NASA Technical Reports Server (NTRS)

    Peltier, W. R.

    1985-01-01

    The connection between the observed large scale structure of the Earths' gravitational field, as represented by the GEM10 model, and the surface kinematic manifestations of plate tectonics, as represented by the absolute plate motion model of Minster and Jordan, is explored using a somewhat novel method of analysis. Two scalar derivatives of the field of surface plate velocities, namely the horizontal divergence and the radial vorticity, are computed from the plate motion data. These two scalars are respectively determined by the poloidal and toroidal scalars in terms of which any essentially solenoidal vector field may be completely represented. They provide a compact summary of the observed plate boundary types in nature, with oceanic ridges and trenches being essentially boundaries of divergence, and transform faults being essentially boundaries of vorticity.

  1. Flow dynamics at a river confluence on Mississippi River: field measurement and large eddy simulation

    NASA Astrophysics Data System (ADS)

    Le, Trung; Khosronejad, Ali; Bartelt, Nicole; Woldeamlak, Solomon; Peterson, Bonnie; Dewall, Petronella; Sotiropoulos, Fotis; Saint Anthony Falls Laboratory, University of Minnesota Team; Minnesota Department of Transportation Team

    2015-11-01

    We study the dynamics of a river confluence on Mississippi River branch in the city of Minneapolis, Minnesota, United States. Field measurements by Acoustic Doppler Current Profiler using on-board GPS tracking were carried out for five campaigns in the summer of 2014 and 2015 to collect both river bed elevation data and flow fields. Large Eddy Simulation is carried out to simulate the flow field with the total of 100 million grid points for the domain length of 3.2 km. The simulation results agree well with field measurements at measured cross-sections. The results show the existence of wake mode on the mixing interface of two branches near the upstream junction corner. The mutual interaction between the shear layers emanating from the river banks leading to the formation of large scale energetic structures that leads to ``switching'' side of the flow coherent structures. Our result here is a feasibility study for the use of eddy-resolving simulations in predicting complex flow dynamics in medium-size natural rivers. This work is funded by Minnesota Dept. Transportation and Minnesota Institute of Supercomputing.

  2. High-Resolution Hα Velocity Fields of Nearby Spiral Galaxies with the Southern African Large Telescope

    NASA Astrophysics Data System (ADS)

    Mitchell, Carl; Williams, Ted; Spekkens, Kristine; Lee-Waddell, Karen; Kuzio de Naray, Rachel; Sellwood, Jerry

    2016-01-01

    In an effort to test ΛCDM predictions of galaxy mass distributions, we have obtained spectrophotometric observations of several nearby spiral galaxies with the Southern African Large Telescope (SALT) Fabry-Pérot (FP) interferometer as part of the RSS Imaging spectroscopy Nearby Galaxy Survey. Utilizing the SALT FP's 8 arcmin field of view and 2 arcsec angular resolution, we have derived 2D velocity fields of the Hα emission line to high spatial resolution at large radii. We have modeled these velocity fields with the DiskFit software package and found them to be in good agreement with lower-resolution velocity fields of the HI 21 cm line for the same galaxies. Here we present our Hα kinematic map of the barred spiral galaxy NGC 578. At the distance to this galaxy (22 Mpc), our kinematic data has a spatial resolution of 185 pc and extends to galactocentric radii of 13 kpc. The high spatial resolution of this data allows us to resolve the inner rising part of the rotation curves, which is compromised by beam smearing in lower-resolution observations. We are using these Hα kinematic data, combined with HI 21 cm kinematics and broadband photometric observations, to place constraints on NGC 578's mass distribution.

  3. Domain wall dynamics in ultrathin Pt/Co/AlOx microstrips under large combined magnetic fields

    NASA Astrophysics Data System (ADS)

    Jué, E.; Thiaville, A.; Pizzini, S.; Miltat, J.; Sampaio, J.; Buda-Prejbeanu, L. D.; Rohart, S.; Vogel, J.; Bonfim, M.; Boulle, O.; Auffret, S.; Miron, I. M.; Gaudin, G.

    2016-01-01

    The dynamics of magnetic domain walls in ultrathin strip-patterned Pt/Co/AlOx samples with perpendicular easy axis has been studied experimentally under an easy-axis field, superposed to a hard-axis field oriented along the strip. The easy-axis field is large so that the domain walls move well beyond the creep regime. A chiral effect is observed where the domain wall velocity shows a monotonous and surprisingly large variation with an in-plane field. A micromagnetic analysis, combining analytic, one-dimensional, and two-dimensional simulations with structural disorder, shows that this behavior can be reproduced with a Dzyaloshinskii-Moriya interaction of the interfacial type, with due consideration of the dynamics of the tilt degree of freedom of the domain wall. The estimated effective value of this interaction (D ≈-2.2 mJ /m2 for a 0.6 nm Co thickness) is consistent with values obtained by other techniques. It is also shown, by micromagnetic analysis, that several modes and characteristic times occur in the dynamics of the tilt of such domain walls.

  4. An improved method for field extraction and laboratory analysis of large, intact soil cores

    USGS Publications Warehouse

    Tindall, J.A.; Hemmen, K.; Dowd, J.F.

    1992-01-01

    Various methods have been proposed for the extraction of large, undisturbed soil cores and for subsequent analysis of fluid movement within the cores. The major problems associated with these methods are expense, cumbersome field extraction, and inadequate simulation of unsaturated flow conditions. A field and laboratory procedure is presented that is economical, convenient, and simulates unsaturated and saturated flow without interface flow problems and can be used on a variety of soil types. In the field, a stainless steel core barrel is hydraulically pressed into the soil (30-cm diam. and 38 cm high), the barrel and core are extracted from the soil, and after the barrel is removed from the core, the core is then wrapped securely with flexible sheet metal and a stainless mesh screen is attached to the bottom of the core for support. In the laboratory the soil core is set atop a porous ceramic plate over which a soil-diatomaceous earth slurry has been poured to assure good contact between plate and core. A cardboard cylinder (mold) is fastened around the core and the empty space filled with paraffin wax. Soil cores were tested under saturated and unsaturated conditions using a hanging water column for potentials ???0. Breakthrough curves indicated that no interface flow occurred along the edge of the core. This procedure proved to be reliable for field extraction of large, intact soil cores and for laboratory analysis of solute transport.

  5. CMB temperature anisotropy at large scales induced by a causal primordial magnetic field

    SciTech Connect

    Bonvin, Camille; Caprini, Chiara E-mail: camille.bonvin@cea.fr

    2010-05-01

    We present an analytical derivation of the Sachs Wolfe effect sourced by a primordial magnetic field. In order to consistently specify the initial conditions, we assume that the magnetic field is generated by a causal process, namely a first order phase transition in the early universe. As for the topological defects case, we apply the general relativistic junction conditions to match the perturbation variables before and after the phase transition which generates the magnetic field, in such a way that the total energy momentum tensor is conserved across the transition and Einstein's equations are satisfied. We further solve the evolution equations for the metric and fluid perturbations at large scales analytically including neutrinos, and derive the magnetic Sachs Wolfe effect. We find that the relevant contribution to the magnetic Sachs Wolfe effect comes from the metric perturbations at next-to-leading order in the large scale limit. The leading order term is in fact strongly suppressed due to the presence of free-streaming neutrinos. We derive the neutrino compensation effect dynamically and confirm that the magnetic Sachs Wolfe spectrum from a causal magnetic field behaves as l(l+1) C{sup B}{sub l}∝l{sup 2} as found in the latest numerical analyses.

  6. Design considerations for large field particle image velocimetery (LF-PIV)

    NASA Astrophysics Data System (ADS)

    Pol, S. U.; Balakumar, B. J.

    2013-02-01

    We discuss the challenges and limitations associated with the development of a large field of view particle image velocimetry (LF-PIV) diagnostic, capable of resolving large-scale motions (>1 m per camera) in gas phase laboratory and field experiments. While this diagnostic is developed for the measurement of wakes and local inflow conditions around research wind turbines, the design considerations provided here are also relevant for the application of LF-PIV to atmospheric boundary layer, rotorcraft dynamics and large-scale wind tunnel flows. Measurements over an area of 0.75 m × 1.0 m on a confined vortex were obtained using a standard 2MP camera, with the potential for increasing this area significantly using 11MP cameras. The cameras in this case were oriented orthogonal to the measurement plane receiving only the side-scattered component of light from the particles. Scaling laws associated with LF-PIV systems are also presented along with the performance analysis of low-density, large diameter Expancel particles, that appear to be promising candidates for LF-PIV seeding.

  7. North American Lauraceae: terpenoid emissions, relative attraction and boring preferences of redbay ambrosia beetle, Xyleborus glabratus (coleoptera: curculionidae: scolytinae).

    PubMed

    Kendra, Paul E; Montgomery, Wayne S; Niogret, Jerome; Pruett, Grechen E; Mayfield, Albert E; MacKenzie, Martin; Deyrup, Mark A; Bauchan, Gary R; Ploetz, Randy C; Epsky, Nancy D

    2014-01-01

    The invasive redbay ambrosia beetle, Xyleborus glabratus, is the primary vector of Raffaelea lauricola, a symbiotic fungus and the etiologic agent of laurel wilt. This lethal disease has caused severe mortality of redbay (Persea borbonia) and swampbay (P. palustris) trees in the southeastern USA, threatens avocado (P. americana) production in Florida, and has potential to impact additional New World species. To date, all North American hosts of X. glabratus and suscepts of laurel wilt are members of the family Lauraceae. This comparative study combined field tests and laboratory bioassays to evaluate attraction and boring preferences of female X. glabratus using freshly-cut bolts from nine species of Lauraceae: avocado (one cultivar of each botanical race), redbay, swampbay, silkbay (Persea humilis), California bay laurel (Umbellularia californica), sassafras (Sassafras albidum), northern spicebush (Lindera benzoin), camphor tree (Cinnamomum camphora), and lancewood (Nectandra coriacea). In addition, volatile collections and gas chromatography-mass spectroscopy (GC-MS) were conducted to quantify terpenoid emissions from test bolts, and electroantennography (EAG) was performed to measure olfactory responses of X. glabratus to terpenoids identified by GC-MS. Significant differences were observed among treatments in both field and laboratory tests. Silkbay and camphor tree attracted the highest numbers of the beetle in the field, and lancewood and spicebush the lowest, whereas boring activity was greatest on silkbay, bay laurel, swampbay, and redbay, and lowest on lancewood, spicebush, and camphor tree. The Guatemalan cultivar of avocado was more attractive than those of the other races, but boring response among the three was equivalent. The results suggest that camphor tree may contain a chemical deterrent to boring, and that different cues are associated with host location and host acceptance. Emissions of α-cubebene, α-copaene, α-humulene, and calamenene were

  8. North American Lauraceae: Terpenoid Emissions, Relative Attraction and Boring Preferences of Redbay Ambrosia Beetle, Xyleborus glabratus (Coleoptera: Curculionidae: Scolytinae)

    PubMed Central

    Kendra, Paul E.; Montgomery, Wayne S.; Niogret, Jerome; Pruett, Grechen E.; Mayfield, Albert E.; MacKenzie, Martin; Deyrup, Mark A.; Bauchan, Gary R.; Ploetz, Randy C.; Epsky, Nancy D.

    2014-01-01

    The invasive redbay ambrosia beetle, Xyleborus glabratus, is the primary vector of Raffaelea lauricola, a symbiotic fungus and the etiologic agent of laurel wilt. This lethal disease has caused severe mortality of redbay (Persea borbonia) and swampbay (P. palustris) trees in the southeastern USA, threatens avocado (P. americana) production in Florida, and has potential to impact additional New World species. To date, all North American hosts of X. glabratus and suscepts of laurel wilt are members of the family Lauraceae. This comparative study combined field tests and laboratory bioassays to evaluate attraction and boring preferences of female X. glabratus using freshly-cut bolts from nine species of Lauraceae: avocado (one cultivar of each botanical race), redbay, swampbay, silkbay (Persea humilis), California bay laurel (Umbellularia californica), sassafras (Sassafras albidum), northern spicebush (Lindera benzoin), camphor tree (Cinnamomum camphora), and lancewood (Nectandra coriacea). In addition, volatile collections and gas chromatography-mass spectroscopy (GC-MS) were conducted to quantify terpenoid emissions from test bolts, and electroantennography (EAG) was performed to measure olfactory responses of X. glabratus to terpenoids identified by GC-MS. Significant differences were observed among treatments in both field and laboratory tests. Silkbay and camphor tree attracted the highest numbers of the beetle in the field, and lancewood and spicebush the lowest, whereas boring activity was greatest on silkbay, bay laurel, swampbay, and redbay, and lowest on lancewood, spicebush, and camphor tree. The Guatemalan cultivar of avocado was more attractive than those of the other races, but boring response among the three was equivalent. The results suggest that camphor tree may contain a chemical deterrent to boring, and that different cues are associated with host location and host acceptance. Emissions of α-cubebene, α-copaene, α-humulene, and calamenene were

  9. Clinical tolerance in large field radiotherapy--the knowledge gained over the last ten years.

    PubMed

    Gocheva, Lilia B

    2010-01-01

    Malignant disorders are still far from being successfully managed in spite of the apparent progress achieved by surgical treatment, high energy radiotherapy (RT) and chemotherapy (CHT). They keep being the second most frequent cause of lethal outcomes both in Bulgaria and in most countries of the world. One of the promising approaches to increasing the efficaciousness of treatment is development and use of methods that are in full accord with the modern requirements of a complex therapy. Over the last fifty years, large field radiation techniques, applied as systemic therapy in oncology, have been investigated and established. These techniques show the transition in oncology to using actively various variants of large field radiotherapy (LFR), the "heavy artillery" of oncoradiologic practice, as an alternative or adjunct therapy to chemotherapy (CHT). In the present paper we review the current knowledge in the field and present the clinical experience accumulated over the last ten years with respect to clinical tolerance in the major large-field radiotherapy techniques--total body irradiation, half body irradiation, whole abdominal irradiation, total and partial lymphoid irradiation. Described in detail are the contemporary knowledge about clinical and hematologic tolerance in total body irradiation as part of the myelo- and nonmyeloablative conditioning regimens as well as in half body irradiation as a systemic therapy in oncology. We also present the amassed experience in clinical tolerance in partial body irradiation in the form of whole abdominal and total or partial lymphoid irradiation. Another point worth noting based again on the experience gained over the last ten years is that for LFR we need to develop a radiotherapy technique that is designed carefully to achieve an optimal therapeutic effect that should include the disease control, good clinical tolerance and reduction of post-radiotherapy sequelae.

  10. Simulating daily rainfall fields over large areas for collective risk estimation

    NASA Astrophysics Data System (ADS)

    Serinaldi, Francesco; Kilsby, Chris G.

    2014-05-01

    Large scale rainfall models are needed for collective risk estimation in flood insurance, infrastructure networks and water resource management applications. There is a lack of models which can provide simulations over large river basins (potentially multi-national) at appropriate spatial resolution (e.g., 5-25 km) that preserve both the local properties of rainfall (i.e., marginal distributions and temporal correlation) and the spatial structure of the field (i.e., the spatial dependence structure). In this study we describe a methodology which merges meta-Gaussian random fields and generalized additive models to simulate realistic rainfall fields at daily time scale over large areas. Unlike other techniques previously proposed in the literature, the suggested approach does not split the rainfall occurrence and intensity processes and resorts to a unique discrete-continuous distribution to reproduce the local properties of rainfall. This choice allows the use of a unique meta-Gaussian spatio-temporal random field substrate that is devised to reproduce the spatial properties and the short term temporal characteristics of the observed precipitation. The model is calibrated and tested on a 25 km gridded daily rainfall data set covering the 817 000 km2 of the Danube basin. Standard and ad hoc diagnostics highlight the overall good performance over the whole range of rainfall values at multiple scales of spatio-temporal aggregation with particular attention to extreme values. Moreover, the modular structure of the model allows for refinements, adaptation to different areas and the introduction of exogenous forcing variables, thus making it a valuable tool for classical hydrologic analyses as well as for new challenges of network and reinsurance risk assessment over extensive areas.

  11. Acoustic characterization of high intensity focused ultrasound fields generated from a transmitter with a large aperture

    SciTech Connect

    Chen, Tao; Fan, Tingbo; Zhang, Wei; Qiu, Yuanyuan; Tu, Juan E-mail: dzhang@nju.edu.cn; Guo, Xiasheng; Zhang, Dong E-mail: dzhang@nju.edu.cn

    2014-03-21

    Prediction and measurement of the acoustic field emitted from a high intensity focused ultrasound (HIFU) is essential for the accurate ultrasonic treatment. In this study, the acoustic field generated from a strongly focused HIFU transmitter was characterized by a combined experiment and simulation method. The spheroidal beam equation (SBE) was utilized to describe the nonlinear sound propagation. The curve of the source pressure amplitude versus voltage excitation was determined by fitting the measured ratio of the second harmonic to the fundamental component of the focal waveform to the simulation result; finally, the acoustic pressure field generated by the strongly focused HIFU transmitter was predicted by using the SBE model. A commercial fiber optic probe hydrophone was utilized to measure the acoustic pressure field generated from a 1.1 MHz HIFU transmitter with a large half aperture angle of 30°. The maximum measured peak-to-peak pressure was up to 72 MPa. The validity of this combined approach was confirmed by the comparison between the measured results and the calculated ones. The results indicate that the current approach might be useful to describe the HIFU field. The results also suggest that this method is not valid for low excitations owing to low sensitivity of the second harmonic.

  12. Deep blank-field catalogue for medium- and large-sized telescopes

    NASA Astrophysics Data System (ADS)

    Jiménez Esteban, F. M.; Cabrera Lavers, A.; Cardiel, N.; Alacid, J. M.

    2012-11-01

    The observation of blank fields, defined as regions of the sky that are devoid of stars down to a given threshold magnitude, constitutes one of the most relevant calibration procedures required for the proper reduction of astronomical data obtained following typical observing strategies. In this work, we have used Delaunay triangulation to search for deep blank fields throughout the whole sky, with a minimum size of 10 arcmin in diameter and an increasing threshold magnitude from 15 to 18 in the R band of the USNO-B Catalog of the United States Naval Observatory. The result is a catalogue with the deepest blank fields known so far. A short sample of these regions has been tested with the 10.4-m Gran Telescopio Canarias, and it has been shown to be extremely useful for medium- and large-sized telescopes. Because some of the regions found could also be suitable for new extragalactic studies, we have estimated the galactic extinction in the direction of each deep blank field. This catalogue is accessible through the virtual observatory tool TESELA, and the user can retrieve - and visualize using ALADIN - the deep blank fields available near a given position in the sky.

  13. Large-field-of-view laser-scanning OR-PAM using a fibre optic sensor

    NASA Astrophysics Data System (ADS)

    Allen, T. J.; Zhang, E.; Beard, P. C.

    2015-03-01

    Laser-Scanning-Optical-Resolution Photoacoustic Microscopy (LSOR-PAM) requires an ultrasound detector with a low noise equivalent pressure (NEP) and a large angular detection aperture in order to image a large field of view (FOV). It is however challenging to meet these requirements when using piezoelectric receivers since using a small sensing element size (<100μm) in order to achieve a large angular detection aperture will inevitability reduce the sensitivity of the detector as it scales with decreasing element size. Fibre optic ultrasound sensors based on a Fabry Perot cavity do not suffer from this limitation and can provide high detection sensitivity (NEP<0.1kPa over a 20 MHz measurement bandwidth) with a large angular detection aperture due to their small active element size (~10μm). A LSOR-PAM system was developed and combined with this type of fibre optic ultrasound sensor. A set of phantom studies were undertaken. The first study demonstrated that a high resolution image over a large field of view (Ø11mm) could be obtained with a sampledetector separation of only 1.6mm. In the second study, a 12μm diameter tube filled with methylene blue whose absorption coefficient was similar to that of blood was visualised demonstrating that the fibre optic sensor could provide sufficient SNR for in-vivo microvascular OR-PAM imaging. These preliminary results suggest that the fibre optic sensor has the potential to outperform piezoelectric detectors for Laser-Scanning Optical Resolution Photoacoustic Microscopy (LSOR-PAM).

  14. Large granular lymphocytic (LGL) leukemia in rats exposed to intermittent 60 Hz magnetic fields.

    PubMed

    Anderson, L E; Morris, J E; Miller, D L; Rafferty, C N; Ebi, K L; Sasser, L B

    2001-04-01

    An animal model for large granular lymphocytic (LGL) leukemia in male Fischer 344 rats was utilized to determine whether magnetic field exposure can be shown to influence the progression of leukemia. We previously reported that exposure to continuous 60 Hz, 1 mT magnetic fields did not significantly alter the clinical progression of LGL leukemia in young male rats following injection of spleen cells from donor leukemic rats. Results presented here extend those studies with the following objectives: (a) to replicate the previous study of continuous 60 Hz magnetic field exposures, but using fewer LGL cells in the inoculum, and (b) to determine if intermittent 60 Hz magnetic fields can alter the clinical progression of leukemia. Rats were randomly assigned to four treatment groups (18/group) as follows: (1) 1 mT (10 G) continuous field, (2) 1 mT intermittent field (off/on at 3 min intervals), (3) ambient controls ( < 0.1 microT), and (4) positive control (5 Gy whole body irradiation from cobalt-60 four days prior to initiation of exposure). All rats were injected intraperitoneally with 2.2 x 10(6) fresh, viable LGL leukemic spleen cells at the beginning of the study. The fields were activated for 20 h per day, 7 days per week, and all exposure conditions were superimposed over the natural ambient magnetic field. The rats were weighed and palpated for splenomegaly weekly. Splenomegaly developed 9-11 weeks after transplantation of the leukemia cells. Hematological evaluations were performed at 6, 8, 10, 12, 14, and 16 weeks of exposure. Peripheral blood hemoglobin concentration, red blood cells, and packed cell volume declined, and total white blood cells and LGL cells increased dramatically in all treatment groups after onset of leukemia. Although the positive control group showed different body weight curves and developed signs of leukemia earlier than other groups, differences were not detected between exposure groups and ambient controls. Furthermore, there were no

  15. Alignments of Dark Matter Halos with Large-scale Tidal Fields: Mass and Redshift Dependence

    NASA Astrophysics Data System (ADS)

    Chen, Sijie; Wang, Huiyuan; Mo, H. J.; Shi, Jingjing

    2016-07-01

    Large-scale tidal fields estimated directly from the distribution of dark matter halos are used to investigate how halo shapes and spin vectors are aligned with the cosmic web. The major, intermediate, and minor axes of halos are aligned with the corresponding tidal axes, and halo spin axes tend to be parallel with the intermediate axes and perpendicular to the major axes of the tidal field. The strengths of these alignments generally increase with halo mass and redshift, but the dependence is only on the peak height, ν \\equiv {δ }{{c}}/σ ({M}{{h}},z). The scaling relations of the alignment strengths with the value of ν indicate that the alignment strengths remain roughly constant when the structures within which the halos reside are still in a quasi-linear regime, but decreases as nonlinear evolution becomes more important. We also calculate the alignments in projection so that our results can be compared directly with observations. Finally, we investigate the alignments of tidal tensors on large scales, and use the results to understand alignments of halo pairs separated at various distances. Our results suggest that the coherent structure of the tidal field is the underlying reason for the alignments of halos and galaxies seen in numerical simulations and in observations.

  16. Large field-induced-strain at high temperature in ternary ferroelectric crystals

    PubMed Central

    Wang, Yaojin; Chen, Lijun; Yuan, Guoliang; Luo, Haosu; Li, Jiefang; Viehland, D.

    2016-01-01

    The new generation of ternary Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 ferroelectric single crystals have potential applications in high power devices due to their surperior operational stability relative to the binary system. In this work, a reversible, large electric field induced strain of over 0.9% at room temperature, and in particular over 0.6% above 380 K was obtained. The polarization rotation path and the phase transition sequence of different compositions in these ternary systems have been determined with increasing electric field applied along [001] direction based on x-ray diffraction data. Thereafter, composition dependence of field-temperature phase diagrams were constructed, which provide compositional and thermal prospectus for the electromechanical properties. It was found the structural origin of the large stain, especially at higher temperature is the lattice parameters modulated by dual independent variables in composition of these ternary solid solution crystals. PMID:27734908

  17. Electron Acceleration at Coronal Shocks Propagating Through a Large-scale Streamer-like Magnetic Field

    NASA Astrophysics Data System (ADS)

    Kong, X.

    2015-12-01

    Solar type II radio bursts are generally believed to be excited by energetic electrons that are accelerated at solar eruption-driven shocks. Some recent studies have pointed out that coronal streamers may be important on the generation of type II bursts and the morphology of radio dynamic spectra. In our previous study, it was found that closed field of the streamer can play the role of an electron trap via which electrons would receive multiple reflection and acceleration. We further developed a numerical model consisting of a spherical coronal shock moving through a large-scale streamer-like coronal magnetic field. The complex local shock geometry should affect both the efficiency of electron acceleration and properties of accelerated electrons. By examining the injection and escape locations of energetic electrons, it is found that shock electron acceleration is most efficient mainly in two different regions, one is at the shock flank (foreshock regions) when the shock is at lower altitude, the other is at the shock nose (apexes of closed loops) at higher altitude. The effects of large-scale coronal field, pitch-angle scattering and shock compression ratio on the distribution of energetic electrons and electron energy spectrum are also investigated.

  18. Large field-induced-strain at high temperature in ternary ferroelectric crystals

    NASA Astrophysics Data System (ADS)

    Wang, Yaojin; Chen, Lijun; Yuan, Guoliang; Luo, Haosu; Li, Jiefang; Viehland, D.

    2016-10-01

    The new generation of ternary Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 ferroelectric single crystals have potential applications in high power devices due to their surperior operational stability relative to the binary system. In this work, a reversible, large electric field induced strain of over 0.9% at room temperature, and in particular over 0.6% above 380 K was obtained. The polarization rotation path and the phase transition sequence of different compositions in these ternary systems have been determined with increasing electric field applied along [001] direction based on x-ray diffraction data. Thereafter, composition dependence of field-temperature phase diagrams were constructed, which provide compositional and thermal prospectus for the electromechanical properties. It was found the structural origin of the large stain, especially at higher temperature is the lattice parameters modulated by dual independent variables in composition of these ternary solid solution crystals.

  19. Large-scale rotational perturbations of a Friedmann universe with collisionless matter and primordial magnetic fields

    NASA Astrophysics Data System (ADS)

    Rebhan, Anton

    1992-06-01

    The dynamical equations for rotational (vector) perturbations of a Friedmann-Robertson-Walker universe containing a perfect fluid of massive matter and radiation together with relativistic collisionless matter are established. These equations have solutions which remain regular as the initial singularity is approached, in contrast to the purely perfect-fluid case, where small rotational perturbations cannot coexist with a Friedmann-type singularity due to the Helmholtz-Kelvin circulation theorem. With collisionless matter present (e.g., gravitons after the Planck era), this obstruction is circumvented, and solutions which exhibit a growing mode of vorticity on superhorizon scales are obtained. The anisotropies in the cosmic microwave background caused by these small vector perturbations are analyzed, and limits on admissible primordial vorticity are derived. In the radiation era, large-scale vorticity gives rise to large-scale primordial magnetic fields, which are shown potentially to have the right magnitude to act as seed fields for galactic dynamo action and thereby to explain the presently observed galactic magnetic fields.

  20. Bore holes and the vanishing of guinea worm disease in Ghana's upper region.

    PubMed

    Hunter, J M

    1997-07-01

    Ghana's Upper Region provides an excellent example of the beneficial effects of improved water security provided by hand-pump tube wells. Following a Ghana-Canada bilateral development project that installed some 2500 pumps, protection rates against guinea worm disease may be estimated as 88% in the west, and 96% in the east. Survey comparisons between ca 1960 and 1990 show that dracunculiasis declined in 32 of a total of 38 areas. The shadow of guinea worm has been lifted from the land and, in many areas, a true "vanishing" has occurred. The few areas of disease increase are characterized by the lowest population densities, pioneer settlement for cotton farming, and an absence of bore holes. Vagaries of development have inadvertently produced disease transformations or "metamorphoses" from dracunculiasis to elephantiasis (lymphatic filariasis) in one area, and to red water disease (schistosomiasis hematobium) in other areas. Correlative associations between pump densities and guinea worm disease are weakened by the large size of areas for which disease is reported in 1990. One preliminary finding is that geographical distance to the pump is a stronger influence than demographic pressure on pumps, regarding dracunculiasis. Diminishing returns on higher pump densities in many areas support the idea of making fuller, safer use of supplementary non-pump water. Despite crises of fee payment and pump maintenance, the rural bore hole project has struck a mortal blow against guinea worm, and permanently raised the quality of life in the Upper Region.

  1. Large-scale full-field metrology using projected fringes: some challenges and solutions

    NASA Astrophysics Data System (ADS)

    Huntley, Jonathan M.; Ogundana, Tokunbo; Burguete, Richard L.; Coggrave, C. Russell

    2007-06-01

    The application of optical techniques to the measurement of shape and deformation of structures in the aerospace industry poses unique challenges resulting from the large length scales involved, which are typically in the 1-10 m range. For example, the relative immobility of large samples requires a network of sensors to be linked into a common global coordinate system; traceable calibration requires the development of new types of calibration artefact; and traditional interferometric techniques for displacement field mapping are frequently too sensitive to observe the physical effect of interest. We describe a system designed to address some of these problems based on the projected fringe technique combined with temporal phase unwrapping. Multiple cameras and projectors are linked into a common coordinate system using calibration concepts borrowed from the photogrammetry field. Traceable calibration is achieved through the use of reference spheres separated by a bar of known length. Traditional two-dimensional image processing techniques for recognizing circles (Hough transforms) have been extended to the automatic detection of spheres within the measured 3-D point clouds. Bundle adjustment software has been developed to refine the camera and projector calibration parameters as well as the rigid body translation and rotation coordinates defining the poses of the calibration artefact. An overview of all these aspects of the developed techniques is given in the paper. Typical results from a compression test on a large scale aluminium structure, performed on-site at Airbus UK using the developed system, are also presented.

  2. Data Compression Algorithm Architecture for Large Depth-of-Field Particle Image Velocimeters

    NASA Technical Reports Server (NTRS)

    Bos, Brent; Memarsadeghi, Nargess; Kizhner, Semion; Antonille, Scott

    2013-01-01

    A large depth-of-field particle image velocimeter (PIV) is designed to characterize dynamic dust environments on planetary surfaces. This instrument detects lofted dust particles, and senses the number of particles per unit volume, measuring their sizes, velocities (both speed and direction), and shape factors when the particles are large. To measure these particle characteristics in-flight, the instrument gathers two-dimensional image data at a high frame rate, typically >4,000 Hz, generating large amounts of data for every second of operation, approximately 6 GB/s. To characterize a planetary dust environment that is dynamic, the instrument would have to operate for at least several minutes during an observation period, easily producing more than a terabyte of data per observation. Given current technology, this amount of data would be very difficult to store onboard a spacecraft, and downlink to Earth. Since 2007, innovators have been developing an autonomous image analysis algorithm architecture for the PIV instrument to greatly reduce the amount of data that it has to store and downlink. The algorithm analyzes PIV images and automatically reduces the image information down to only the particle measurement data that is of interest, reducing the amount of data that is handled by more than 10(exp 3). The state of development for this innovation is now fairly mature, with a functional algorithm architecture, along with several key pieces of algorithm logic, that has been proven through field test data acquired with a proof-of-concept PIV instrument.

  3. DNA from Dust: Comparative Genomics of Large DNA Viruses in Field Surveillance Samples.

    PubMed

    Pandey, Utsav; Bell, Andrew S; Renner, Daniel W; Kennedy, David A; Shreve, Jacob T; Cairns, Chris L; Jones, Matthew J; Dunn, Patricia A; Read, Andrew F; Szpara, Moriah L

    2016-01-01

    The intensification of the poultry industry over the last 60 years facilitated the evolution of increased virulence and vaccine breaks in Marek's disease virus (MDV-1). Full-genome sequences are essential for understanding why and how this evolution occurred, but what is known about genome-wide variation in MDV comes from laboratory culture. To rectify this, we developed methods for obtaining high-quality genome sequences directly from field samples without the need for sequence-based enrichment strategies prior to sequencing. We applied this to the first characterization of MDV-1 genomes from the field, without prior culture. These viruses were collected from vaccinated hosts that acquired naturally circulating field strains of MDV-1, in the absence of a disease outbreak. This reflects the current issue afflicting the poultry industry, where virulent field strains continue to circulate despite vaccination and can remain undetected due to the lack of overt disease symptoms. We found that viral genomes from adjacent field sites had high levels of overall DNA identity, and despite strong evidence of purifying selection, had coding variations in proteins associated with virulence and manipulation of host immunity. Our methods empower ecological field surveillance, make it possible to determine the basis of viral virulence and vaccine breaks, and can be used to obtain full genomes from clinical samples of other large DNA viruses, known and unknown. IMPORTANCE Despite both clinical and laboratory data that show increased virulence in field isolates of MDV-1 over the last half century, we do not yet understand the genetic basis of its pathogenicity. Our knowledge of genome-wide variation between strains of this virus comes exclusively from isolates that have been cultured in the laboratory. MDV-1 isolates tend to lose virulence during repeated cycles of replication in the laboratory, raising concerns about the ability of cultured isolates to accurately reflect virus in

  4. DNA from Dust: Comparative Genomics of Large DNA Viruses in Field Surveillance Samples

    PubMed Central

    Pandey, Utsav; Bell, Andrew S.; Renner, Daniel W.; Kennedy, David A.; Shreve, Jacob T.; Cairns, Chris L.; Jones, Matthew J.; Dunn, Patricia A.; Read, Andrew F.

    2016-01-01

    ABSTRACT The intensification of the poultry industry over the last 60 years facilitated the evolution of increased virulence and vaccine breaks in Marek’s disease virus (MDV-1). Full-genome sequences are essential for understanding why and how this evolution occurred, but what is known about genome-wide variation in MDV comes from laboratory culture. To rectify this, we developed methods for obtaining high-quality genome sequences directly from field samples without the need for sequence-based enrichment strategies prior to sequencing. We applied this to the first characterization of MDV-1 genomes from the field, without prior culture. These viruses were collected from vaccinated hosts that acquired naturally circulating field strains of MDV-1, in the absence of a disease outbreak. This reflects the current issue afflicting the poultry industry, where virulent field strains continue to circulate despite vaccination and can remain undetected due to the lack of overt disease symptoms. We found that viral genomes from adjacent field sites had high levels of overall DNA identity, and despite strong evidence of purifying selection, had coding variations in proteins associated with virulence and manipulation of host immunity. Our methods empower ecological field surveillance, make it possible to determine the basis of viral virulence and vaccine breaks, and can be used to obtain full genomes from clinical samples of other large DNA viruses, known and unknown. IMPORTANCE Despite both clinical and laboratory data that show increased virulence in field isolates of MDV-1 over the last half century, we do not yet understand the genetic basis of its pathogenicity. Our knowledge of genome-wide variation between strains of this virus comes exclusively from isolates that have been cultured in the laboratory. MDV-1 isolates tend to lose virulence during repeated cycles of replication in the laboratory, raising concerns about the ability of cultured isolates to accurately

  5. Non-mean-field theory of anomalously large double layer capacitance.

    PubMed

    Loth, M S; Skinner, Brian; Shklovskii, B I

    2010-07-01

    Mean-field theories claim that the capacitance of the double layer formed at a metal/ionic conductor interface cannot be larger than that of the Helmholtz capacitor, whose width is equal to the radius of an ion. However, in some experiments the apparent width of the double layer capacitor is substantially smaller. We propose an alternate non-mean-field theory of the ionic double layer to explain such large capacitance values. Our theory allows for the binding of discrete ions to their image charges in the metal, which results in the formation of interface dipoles. We focus primarily on the case where only small cations are mobile and other ions form an oppositely charged background. In this case, at small temperature and zero applied voltage dipoles form a correlated liquid on both contacts. We show that at small voltages the capacitance of the double layer is determined by the transfer of dipoles from one electrode to the other and is therefore limited only by the weak dipole-dipole repulsion between bound ions so that the capacitance is very large. At large voltages the depletion of bound ions from one of the capacitor electrodes triggers a collapse of the capacitance to the much smaller mean-field value, as seen in experimental data. We test our analytical predictions with a Monte Carlo simulation and find good agreement. We further argue that our "one-component plasma" model should work well for strongly asymmetric ion liquids. We believe that this work also suggests an improved theory of pseudocapacitance.

  6. Phase diagram of a two-dimensional large- Q Potts model in an external field

    NASA Astrophysics Data System (ADS)

    Tsai, Shan-Ho; Landau, D. P.

    2009-04-01

    We use a two-dimensional Wang-Landau sampling algorithm to map out the phase diagram of a Q-state Potts model with Q⩽10 in an external field H that couples to one state. Finite-size scaling analyses show that for large Q the first-order phase transition point at H=0 is in fact a triple point at which three first-order phase transition lines meet. One such line is restricted to H=0; another line has H⩽0. The third line, which starts at the H=0 triple point, ends at a critical point (T,H) which needs to be located in a two-dimensional parameter space. The critical field H(Q) is positive and decreases with decreasing Q, which is in qualitative agreement with previous predictions.

  7. Large amplitude spin torque vortex oscillations at zero external field using a perpendicular spin polarizer

    SciTech Connect

    Dussaux, A.; Rache Salles, B.; Jenkins, A. S.; Bortolotti, P.; Grollier, J.; Cros, V.; Fert, A.; Khvalkovskiy, A. V.; Kubota, H.; Fukushima, A.; Yakushiji, K.; Yuasa, S.

    2014-07-14

    We investigate the microwave response of a spin transfer vortex based oscillator in a magnetic tunnel junction with an in-plane reference layer combined with a spin valve with an out-of-plane magnetization spin polarizing layer. The main advantage of this perpendicular spin polarizer is to induce a large spin transfer force even at zero magnetic field, thus leading to a record emitted power (up to 0.6 μW) associated to a very narrow spectral linewidth of a few hundreds of kHz. The characteristics of this hybrid vortex based spin transfer nano-oscillator obtained at zero field and room temperature are of great importance for applications based on rf spintronic devices as integrated and tunable microwave source and/or microwave detector.

  8. Improved confinement region without large magnetohydrodynamic activity in TPE-RX reversed-field pinch plasma

    NASA Astrophysics Data System (ADS)

    Yambe, Kiyoyuki; Hirano, Yoichi; Sakakita, Hajime; Koguchi, Haruhisa

    2014-11-01

    We found that spontaneous improved confinement was brought about depending on the operating region in the Toroidal Pinch Experiment-Reversed eXperiment (TPE-RX) reversed-field pinch plasma [Y. Yagi et al., Fusion Eng. Des. 45, 421 (1999)]. Gradual decay of the toroidal magnetic field at plasma surface Btw reversal makes it possible to realize a prolonged discharge, and the poloidal beta value and energy confinement time increase in the latter half of the discharge, where reversal and pinch parameters become shallow and low, respectively. In the latter half of the discharge, the plasma current and volume-averaged toroidal magnetic field increase again, the electron density slowly decays, the electron temperature and soft X-ray radiation intensity increase, and the magnetic fluctuations are markedly reduced. In this period of improved confinement, the value of (-Btw)/Bpw, where Bpw is the poloidal magnetic field at the plasma surface, stays almost constant, which indicates that the dynamo action occurs without large magnetohydrodynamic activities.

  9. Improved confinement region without large magnetohydrodynamic activity in TPE-RX reversed-field pinch plasma

    SciTech Connect

    Yambe, Kiyoyuki; Hirano, Yoichi; Sakakita, Hajime; Koguchi, Haruhisa

    2014-11-15

    We found that spontaneous improved confinement was brought about depending on the operating region in the Toroidal Pinch Experiment-Reversed eXperiment (TPE-RX) reversed-field pinch plasma [Y. Yagi et al., Fusion Eng. Des. 45, 421 (1999)]. Gradual decay of the toroidal magnetic field at plasma surface B{sub tw} reversal makes it possible to realize a prolonged discharge, and the poloidal beta value and energy confinement time increase in the latter half of the discharge, where reversal and pinch parameters become shallow and low, respectively. In the latter half of the discharge, the plasma current and volume-averaged toroidal magnetic field 〈B{sub t}〉 increase again, the electron density slowly decays, the electron temperature and soft X-ray radiation intensity increase, and the magnetic fluctuations are markedly reduced. In this period of improved confinement, the value of (〈B{sub t}〉-B{sub tw})/B{sub pw}, where B{sub pw} is the poloidal magnetic field at the plasma surface, stays almost constant, which indicates that the dynamo action occurs without large magnetohydrodynamic activities.

  10. Modeling an unmitigated thermal quench event in a large field magnet in a DEMO reactor

    DOE PAGES

    Merrill, Brad J.

    2015-03-25

    The superconducting magnet systems of future fusion reactors, such as a Demonstration Power Plant (DEMO), will produce magnetic field energies in the 10 s of GJ range. The release of this energy during a fault condition could produce arcs that can damage the magnets of these systems. The public safety consequences of such events must be explored for a DEMO reactor because the magnets are located near the DEMO's primary radioactive confinement barrier, the reactor's vacuum vessel (VV). Great care will be taken in the design of DEMO's magnet systems to detect and provide a rapid field energy dump tomore » avoid any accidents conditions. During an event when a fault condition proceeds undetected, the potential of producing melting of the magnet exists. If molten material from the magnet impinges on the walls of the VV, these walls could fail, resulting in a pathway for release of radioactive material from the VV. A model is under development at Idaho National Laboratory (INL) called MAGARC to investigate the consequences of this accident in a large toroidal field (TF) coil. Recent improvements to this model are described in this paper, along with predictions for a DEMO relevant event in a toroidal field magnet.« less

  11. Optimization of a large integrated area development of gas fields offshore Sarawak, Malaysia

    SciTech Connect

    Inyang, S.E.; Tak, A.N.H.; Costello, G.

    1995-10-01

    Optimizations of field development plans are routine in the industry. The size, schedule and nature of the upstream gas supply project to the second Malaysia LNG (MLNG Dua) plant in Bintulu, Sarawak made the need for extensive optimizations critical to realizing a robust and cost effective development scheme, and makes the work of more general interest. The project comprises the upstream development of 11 offshore fields for gas supply to MLNG Dua plant at an initial plateau production of 7.8 million tons per year of LNG. The gas fields span a large geographical area in medium water depths (up to 440 ft), and contain gas reserves of a distinctly variable gas quality. This paper describes the project optimization efforts aimed to ensure an upstream gas supply system effectiveness of over 99% throughout the project life while maintaining high safety and environmental standards and also achieving an economic development in an era of low hydrocarbon prices. Fifty percent of the first of the three phases of this gas supply project has already been completed and the first gas from these fields is scheduled to be available by the end of 1995.

  12. Modeling an unmitigated thermal quench event in a large field magnet in a DEMO reactor

    SciTech Connect

    Merrill, Brad J.

    2015-03-25

    The superconducting magnet systems of future fusion reactors, such as a Demonstration Power Plant (DEMO), will produce magnetic field energies in the 10 s of GJ range. The release of this energy during a fault condition could produce arcs that can damage the magnets of these systems. The public safety consequences of such events must be explored for a DEMO reactor because the magnets are located near the DEMO's primary radioactive confinement barrier, the reactor's vacuum vessel (VV). Great care will be taken in the design of DEMO's magnet systems to detect and provide a rapid field energy dump to avoid any accidents conditions. During an event when a fault condition proceeds undetected, the potential of producing melting of the magnet exists. If molten material from the magnet impinges on the walls of the VV, these walls could fail, resulting in a pathway for release of radioactive material from the VV. A model is under development at Idaho National Laboratory (INL) called MAGARC to investigate the consequences of this accident in a large toroidal field (TF) coil. Recent improvements to this model are described in this paper, along with predictions for a DEMO relevant event in a toroidal field magnet.

  13. Disruption in climatic rhythm and anomalous cooling during large decreases in geomagnetic field intensity

    NASA Astrophysics Data System (ADS)

    Kitaba, I.; Hyodo, M.; Katoh, S.; Sato, H.; Matsushita, M.

    2011-12-01

    The Earth's climate is regulated by many factors. Especially, the orbital elements have a large influence on climate. Are there any factors which impact this strong regulation force? The galactic cosmic ray (CR) can be a candidate for such factors. The correlation between CR flux and global cloud cover suggests that the geomagnetic field affects the Earth's climate. CR is strongly modulated by the geomagnetic field. During the geomagnetic polarity reversal, the decrease in field intensity causes an increase in CR flux which would raise cloud cover. In order to examine this effect in the geological past, we examined climate and sea-level changes focusing on marine oxygen isotope stages (MIS) 31 to 17. The climate changes well accord with eustatic sea-level variations dominated by the Earth's orbital elements. However, in MIS 31 and 19, the thermal maximum was clearly lagged behind the sea-level highstand, and instead anomalous cooling occurred. These interglacial periods have the Lower Jaramillo and Matuyama-Brunhes geomagnetic polarity reversals, respectively. Comparing the climate and relative paleointensity variations for the interglacials, the cooling event coincides with the paleointensity minimum associated with the geomagnetic reversal. The coincidence suggests that the geomagnetic field decrease may have caused the disruption of the orbitally forced Earth's climate rhythm.

  14. Development of Dynamic Flow Field Pressure Probes Suitable for Use in Large Scale Supersonic Wind Tunnels

    NASA Technical Reports Server (NTRS)

    Porro, A. Robert

    2000-01-01

    A series of dynamic flow field pressure probes were developed for use in large-scale supersonic wind tunnels at NASA Glenn Research Center. These flow field probes include pitot, static, and five-hole conical pressure probes that are capable of capturing fast acting flow field pressure transients that occur on a millisecond time scale. The pitot and static probes can be used to determine local Mach number time histories during a transient event. The five-hole conical pressure probes are used primarily to determine local flow angularity, but can also determine local Mach number. These probes were designed, developed, and tested at the NASA Glenn Research Center. They were also used in a NASA Glenn 10-by 10-Foot Supersonic Wind Tunnel (SWT) test program where they successfully acquired flow field pressure data in the vicinity of a propulsion system during an engine compressor staff and inlet unstart transient event. Details of the design, development, and subsequent use of these probes are discussed in this report.

  15. The large-scale integration of high-performance silicon nanowire field effect transistors.

    PubMed

    Li, Qiliang; Zhu, Xiaoxiao; Yang, Yang; Ioannou, Dimitris E; Xiong, Hao D; Kwon, Doo-Won; Suehle, John S; Richter, Curt A

    2009-10-14

    In this work we present a CMOS-compatible self-aligning process for the large-scale-integration of high-performance nanowire field effect transistors with well-saturated drain currents, steep subthreshold slopes at low drain voltage and a large on/off current ratio (>10(7)). The subthreshold swing is as small as 45 mV/dec, which is substantially beyond the thermodynamic limit (60 mV/dec) of conventional planar MOSFETs. These excellent device characteristics are achieved by using a clean integration process and a device structure that allows effective gate-channel-source coupling to tune the source/drain Schottky barriers at the nanoscale.

  16. Ultra-large field-of-view two-photon microscopy

    PubMed Central

    Tsai, Philbert S.; Mateo, Celine; Field, Jeffrey J.; Schaffer, Chris B.; Anderson, Matthew E.; Kleinfeld, David

    2015-01-01

    We present a two-photon microscope that images the full extent of murine cortex with an objective-limited spatial resolution across an 8 mm by 10 mm field. The lateral resolution is approximately 1 µm and the maximum scan speed is 5 mm/ms. The scan pathway employs large diameter compound lenses to minimize aberrations and performs near theoretical limits. We demonstrate the special utility of the microscope by recording resting-state vasomotion across both hemispheres of the murine brain through a transcranial window and by imaging histological sections without the need to stitch. PMID:26072755

  17. Ultra-large field-of-view two-photon microscopy.

    PubMed

    Tsai, Philbert S; Mateo, Celine; Field, Jeffrey J; Schaffer, Chris B; Anderson, Matthew E; Kleinfeld, David

    2015-06-01

    We present a two-photon microscope that images the full extent of murine cortex with an objective-limited spatial resolution across an 8 mm by 10 mm field. The lateral resolution is approximately 1 µm and the maximum scan speed is 5 mm/ms. The scan pathway employs large diameter compound lenses to minimize aberrations and performs near theoretical limits. We demonstrate the special utility of the microscope by recording resting-state vasomotion across both hemispheres of the murine brain through a transcranial window and by imaging histological sections without the need to stitch.

  18. Large-Scale Field Study of Landfill Covers at Sandia National Laboratories

    SciTech Connect

    Dwyer, S.F.

    1998-09-01

    A large-scale field demonstration comparing final landfill cover designs has been constructed and is currently being monitored at Sandia National Laboratories in Albuquerque, New Mexico. Two conventional designs (a RCRA Subtitle `D' Soil Cover and a RCRA Subtitle `C' Compacted Clay Cover) were constructed side-by-side with four alternative cover test plots designed for dry environments. The demonstration is intended to evaluate the various cover designs based on their respective water balance performance, ease and reliability of construction, and cost. This paper presents an overview of the ongoing demonstration.

  19. Large-acceptance-angle gridded analyzers in an axial magnetic field

    SciTech Connect

    Molvik, A.W.

    1981-06-01

    Electrostatic retarding-potential gridded analyzers have been used to measure the current and the axial energy distributions of ions escaping along magnetic field lines in the 2XIIB magnetic mirror fusion experiment at Lawerence Livermore National Laboratory (LLNL). Three analyzers are discussed: a large scanning analyzer with a movable entrance aperture that can measure ion or electron losses from a different segment of the plasma diameter on each shot, a smaller analyzer that mounts in 5-cm-diam ports, and a multicollector analyzer that can continuously measure losses from the entire plasma diameter.

  20. Studies of Electronic Properties of Medium and Large Molecules Oriented in a Strong Uniform Electric Field

    NASA Astrophysics Data System (ADS)

    Kong, Wei

    Polarization spectroscopy of oriented gas phase medium and large molecules achieved via a uniform DC electric field provides a means to determine the direction of transition dipoles. In this article, the theoretical background of this orientation method, its characterization, and its application in studies of electronic transitions, will be presented. Mature gas phase spectroscopic methods have been developed for studies of small molecules, but studies of medium to large sized species are faced with special challenges. These challenges arise from differences between large and small molecules: large systems typically exhibit fast internal conversion, slow dissociation, and low translational energy release upon dissociation. Thus conventional gas phase spectroscopic techniques are not applicable to derive the direction of the transition dipole. DC induced orientation offers a solution to this problem. It is ideal for studies of systems with small rotational constants and large permanent dipoles, even when a detailed knowledge of the molecular structure, such as the direction of the permanent dipole in the molecular frame, is unknown. The degree of orientation can be calculated using the linear variation method, given the rotational temperature and the size of the permanent dipole. The associated experimental observables can be used to confirm the effect of orientation, or to determine the direction of a transition dipole. These observables include the ratio of excitation probabilities under different polarization directions and spectroscopic features. In some cases, the direction and size of the permanent dipole of the excited electronic state can also be determined. Examples of this type of polarization spectroscopy are presented for asymmetric tops such as diazines, acetelye-HF clusters, nitroaromatics and butyl nitrite. Illustrations of pendular states and its application in linear and diatomic molecules are also briefed. Applications of this method for studies of

  1. Field experimental study of the Smagorinsky model and application to large eddy simulation

    NASA Astrophysics Data System (ADS)

    Kleissl, Jan

    Large-eddy simulation (LES) has become an indispensable tool for prediction of turbulent atmospheric boundary layer (ABL) flow. In LES, a subgrid-scale (SGS) model accounts for the dynamics of the unresolved scales of motion. The most widely used SGS model is an eddy-viscosity closure, the Smagorinsky model, which includes a parameter that must be prescribed in some fashion, the Smagorinsky constant cs. In this dissertation, cs is measured in a specifically designed field experiment. And, the ability of so-called dynamic SGS models to predict c s is studied based on the data obtained, as well as in numerical simulations. In the field study, two vertically separated horizontal arrays of 3d-sonic anemometers are placed in the atmospheric surface layer. Results indicate that cs is reduced when the integral scale of turbulence is small compared to the grid or filter scale, such as near the ground and in stable atmospheric conditions. The field data are processed further to test whether dynamic SGS models can predict the correct coefficient values. In the scale-invariant dynamic model (Germano et al. 1991), the coefficient is derived from various data test-filtered at a larger scale assuming that cs is the same as at scale Delta. The results show that cs is significantly underpredicted whenever Delta is larger than the large-scale limit of the inertial range. The scale-dependent dynamic model (Porte-Agel et al. 2000b) uses a second test-filter to deduce the dependence of cs on filtering scale. This model provides excellent predictions of cs and its dependence upon stability and height. Large eddy simulations of flow over a homogeneous surface with a diurnal heat flux forcing are conducted to study the prediction of c s over a wide range of stabilities in a numerical framework. The scale-invariant and scale-dependent Lagrangian dynamic SGS model are tested and compared to the field data. Consistent with the field studies, the prediction of cs from the scale

  2. The IR-resummed Effective Field Theory of Large Scale Structures

    SciTech Connect

    Senatore, Leonardo; Zaldarriaga, Matias E-mail: matiasz@ias.edu

    2015-02-01

    We present a new method to resum the effect of large scale motions in the Effective Field Theory of Large Scale Structures. Because the linear power spectrum in ΛCDM is not scale free the effects of the large scale flows are enhanced. Although previous EFT calculations of the equal-time density power spectrum at one and two loops showed a remarkable agreement with numerical results, they also showed a 2% residual which appeared related to the BAO oscillations. We show that this was indeed the case, explain the physical origin and show how a Lagrangian based calculation removes this differences. We propose a simple method to upgrade existing Eulerian calculations to effectively make them Lagrangian and compare the new results with existing fits to numerical simulations. Our new two-loop results agrees with numerical results up to k∼ 0.6 h Mpc{sup −1} to within 1% with no oscillatory residuals. We also compute power spectra involving momentum which is significantly more affected by the large scale flows. We show how keeping track of these velocities significantly enhances the UV reach of the momentum power spectrum in addition to removing the BAO related residuals. We compute predictions for the real space correlation function around the BAO scale and investigate its sensitivity to the EFT parameters and the details of the resummation technique.

  3. The beginning of observations of large-scale solar magnetic fields at the Sayan Observatory - Instrument, plans, preliminary results

    NASA Astrophysics Data System (ADS)

    Grigoryev, V. M.; Peshcherov, V. S.; Demidov, M. L.

    A telescope and a system for measuring large-scale magnetic fields and the large-scale field of line-of-sight velocities in the sun photosphere have been constructed at the Sayan Observatory (USSR). The instrument permits the following synoptic observations of large-scale structures: (1) magnetograms of a large-scale magnetic field with a 3-arcmin resolution and 0.1-0.2 Gs sensitivity; (2) solar disk magnetograms in the form of half-tone images of the magnetic field distribution with 15 Gs sensitivity and 8 x 8 arcsec resolution; and (3) measurement of the mean magnetic field of the sun as a star with about 0.1 Gs sensitivity. Preliminary results of toroidal magnetic field observations are briefly discussed.

  4. British experience with the self-boring pressuremeter

    NASA Astrophysics Data System (ADS)

    Wroth, C. P.

    The optimum position of the cutter of a soil pressuremeter is discussed and experience gained in geotechnical engineering applications are reviewed emphasizing the use of the instrument for the measurement of the shear modulus of the ground. The effects of the cutter position on the degree of disturbance of the ground being bored is analyzed, showing that an adjustment of the rotative cutter position relative to the sharp cutting edge of the cylindrical container minimizes ground disturbances. Use of the instrument in clay and sand soils is detailed. Measurements of the shear modulus together with the effective lateral stress are obtained for finite element computations in realistic models of soil behavior.

  5. Small bore ceramic laser tube inspection light table

    DOEpatents

    Updike, Earl O.

    1990-01-01

    Apparatus for inspecting small bore ceramic laser tubes, which includes a support base with one or more support rollers. A fluorescent light tube is inserted within the laser tube and the laser tube is supported by the support rollers so that a gap is maintained between the laser tube and the fluorescent tube to enable rotation of the laser tube. In operation, the ceramic tube is illuminated from the inside by the fluorescent tube to facilitate visual inspection. Centering the tube around the axial light of the fluorescent tube provides information about straightness and wall thickness of the laser tube itself.

  6. Microcomputer Boring and Subsurface Data Package: User’s Guide.

    DTIC Science & Technology

    1985-09-01

    have been written using dBASE II (trademark of Ashton-Tate) software on a microcomputer with the MS-DOS (trademark of Microsoft Corp.) or the CP /M...Places *4 TOTAL 4* 00141 Figure 2. Structure for BORDBM data hase f iles ,%B - - -Z MS-O --- "- DBASE -- DO BORORN CP /M MAIN MENU FOR BORING DATA BASE... PORNO STORE (EWHCORD-EWLCORD)/EWINC+COL TO MAXCOL *start of main do loop **** main do loop * DO WHILE .NOT. EOF IF NSCORD/(nsinc*10) =INT(NSCORD/(nsinc

  7. Virtually distortion-free imaging system for large field, high resolution lithography using electrons, ions or other particle beams

    DOEpatents

    Hawryluk, Andrew M.; Ceglio, Natale M.

    1993-01-01

    Virtually distortion free large field high resolution imaging is performed using an imaging system which contains large field distortion or field curvature. A reticle is imaged in one direction through the optical system to form an encoded mask. The encoded mask is then imaged back through the imaging system onto a wafer positioned at the reticle position. Particle beams, including electrons, ions and neutral particles, may be used as well as electromagnetic radiation.

  8. Virtually distortion-free imaging system for large field, high resolution lithography using electrons, ions or other particle beams

    DOEpatents

    Hawryluk, A.M.; Ceglio, N.M.

    1993-01-12

    Virtually distortion free large field high resolution imaging is performed using an imaging system which contains large field distortion or field curvature. A reticle is imaged in one direction through the optical system to form an encoded mask. The encoded mask is then imaged back through the imaging system onto a wafer positioned at the reticle position. Particle beams, including electrons, ions and neutral particles, may be used as well as electromagnetic radiation.

  9. Optimal simulations of ultrasonic fields produced by large thermal therapy arrays using the angular spectrum approach.

    PubMed

    Zeng, Xiaozheng; McGough, Robert J

    2009-05-01

    The angular spectrum approach is evaluated for the simulation of focused ultrasound fields produced by large thermal therapy arrays. For an input pressure or normal particle velocity distribution in a plane, the angular spectrum approach rapidly computes the output pressure field in a three dimensional volume. To determine the optimal combination of simulation parameters for angular spectrum calculations, the effect of the size, location, and the numerical accuracy of the input plane on the computed output pressure is evaluated. Simulation results demonstrate that angular spectrum calculations performed with an input pressure plane are more accurate than calculations with an input velocity plane. Results also indicate that when the input pressure plane is slightly larger than the array aperture and is located approximately one wavelength from the array, angular spectrum simulations have very small numerical errors for two dimensional planar arrays. Furthermore, the root mean squared error from angular spectrum simulations asymptotically approaches a nonzero lower limit as the error in the input plane decreases. Overall, the angular spectrum approach is an accurate and robust method for thermal therapy simulations of large ultrasound phased arrays when the input pressure plane is computed with the fast nearfield method and an optimal combination of input parameters.

  10. Effects of larval density in Ambystoma opacum: An experiment in large-scale field enclosures

    SciTech Connect

    Scott, D.E. )

    1990-02-01

    This experiment was designed to measure the effects of larval density on larval traits in the salamander Ambystoma opacum, and to ascertain whether previous studies conducted at smaller spatial scales or higher densities produced artifactual results. Density effects on larval growth, body size at metamorphosis, length of larval period, and survival to metamorphosis were studied in A. opacum in large-scale (41 m{sup 2} and 23 m{sup 2}) field enclosures in two temporary ponds. Each enclosure contained indigenous populations of prey (zooplankton and insects) and predators, as well as the range of microhabitats present in these natural ponds. Initial larval densities were chosen to represent high and low levels of naturally occurring mean densities. The results suggest that, in natural ponds, the importance of intraspecific competition is dependent upon hydroperiod, and the intensity of competition influences predation risk. Thus, both density-dependent and density-independent factors affect body size and recruitment of larval A. opacum into the adult population. The use of large-scale field enclosures has advantages and disadvantages: it allows the examination of density-dependent processes under natural conditions and provides high statistical power because of low variability in larval traits; however, experimental designs must be simple and underlying mechanisms are difficult to identify.

  11. Photometric Calibration and Image Stitching for a Large Field of View Multi-Camera System

    PubMed Central

    Lu, Yu; Wang, Keyi; Fan, Gongshu

    2016-01-01

    A new compact large field of view (FOV) multi-camera system is introduced. The camera is based on seven tiny complementary metal-oxide-semiconductor sensor modules covering over 160° × 160° FOV. Although image stitching has been studied extensively, sensor and lens differences have not been considered in previous multi-camera devices. In this study, we have calibrated the photometric characteristics of the multi-camera device. Lenses were not mounted on the sensor in the process of radiometric response calibration to eliminate the influence of the focusing effect of uniform light from an integrating sphere. Linearity range of the radiometric response, non-linearity response characteristics, sensitivity, and dark current of the camera response function are presented. The R, G, and B channels have different responses for the same illuminance. Vignetting artifact patterns have been tested. The actual luminance of the object is retrieved by sensor calibration results, and is used to blend images to make panoramas reflect the objective luminance more objectively. This compensates for the limitation of stitching images that are more realistic only through the smoothing method. The dynamic range limitation of can be resolved by using multiple cameras that cover a large field of view instead of a single image sensor with a wide-angle lens. The dynamic range is expanded by 48-fold in this system. We can obtain seven images in one shot with this multi-camera system, at 13 frames per second. PMID:27077857

  12. A large field of view two-photon mesoscope with subcellular resolution for in vivo imaging

    PubMed Central

    Sofroniew, Nicholas James; Flickinger, Daniel; King, Jonathan; Svoboda, Karel

    2016-01-01

    Imaging is used to map activity across populations of neurons. Microscopes with cellular resolution have small (<1 millimeter) fields of view and cannot simultaneously image activity distributed across multiple brain areas. Typical large field of view microscopes do not resolve single cells, especially in the axial dimension. We developed a 2-photon random access mesoscope (2p-RAM) that allows high-resolution imaging anywhere within a volume spanning multiple brain areas (∅ 5 mm x 1 mm cylinder). 2p-RAM resolution is near diffraction limited (lateral, 0.66 μm, axial 4.09 μm at the center; excitation wavelength = 970 nm; numerical aperture = 0.6) over a large range of excitation wavelengths. A fast three-dimensional scanning system allows efficient sampling of neural activity in arbitrary regions of interest across the entire imaging volume. We illustrate the use of the 2p-RAM by imaging neural activity in multiple, non-contiguous brain areas in transgenic mice expressing protein calcium sensors. DOI: http://dx.doi.org/10.7554/eLife.14472.001 PMID:27300105

  13. A large-field polarisation-resolved laser scanning microscope: applications to CARS imaging.

    PubMed

    DE Vito, G; Canta, A; Marmiroli, P; Piazza, V

    2015-11-01

    Laser-scanning imaging techniques are frequently used to probe the molecule spatial orientation in a sample of interest by exploiting selection rules depending on the polarisation of the excitation light. For the successful implementation of these techniques the precise control of the polarisation at the sample level is of fundamental importance. Polarisation distortions induced by the optical elements are often the main limitation factor for the maximum size of the field-of-view in polarisation-resolved (PR) laser-scanning microscopy, since for large scanning angles the polarisation distortions may mask the real sample structure. Here we shall demonstrate the implementation of large-field-of-view PR microscopy and show PR CARS imaging of mouse spinal cord thanks to a careful design of the laser-beam optical path. We shall show that this design leads to strongly suppressed distortions and quantify their effects on the final images. Although the focus of this work is on CARS imaging, we stress that the approaches described here can be successfully applied to a wide range of PR laser-scanning techniques.

  14. Photometric Calibration and Image Stitching for a Large Field of View Multi-Camera System.

    PubMed

    Lu, Yu; Wang, Keyi; Fan, Gongshu

    2016-04-11

    A new compact large field of view (FOV) multi-camera system is introduced. The camera is based on seven tiny complementary metal-oxide-semiconductor sensor modules covering over 160° × 160° FOV. Although image stitching has been studied extensively, sensor and lens differences have not been considered in previous multi-camera devices. In this study, we have calibrated the photometric characteristics of the multi-camera device. Lenses were not mounted on the sensor in the process of radiometric response calibration to eliminate the influence of the focusing effect of uniform light from an integrating sphere. Linearity range of the radiometric response, non-linearity response characteristics, sensitivity, and dark current of the camera response function are presented. The R, G, and B channels have different responses for the same illuminance. Vignetting artifact patterns have been tested. The actual luminance of the object is retrieved by sensor calibration results, and is used to blend images to make panoramas reflect the objective luminance more objectively. This compensates for the limitation of stitching images that are more realistic only through the smoothing method. The dynamic range limitation of can be resolved by using multiple cameras that cover a large field of view instead of a single image sensor with a wide-angle lens. The dynamic range is expanded by 48-fold in this system. We can obtain seven images in one shot with this multi-camera system, at 13 frames per second.

  15. The significance of large variations in oil properties of the Dai Hung field, Vietnam

    SciTech Connect

    Behrenbruch, P.; Du, P.Q.

    1995-10-01

    The Dai Hung Oil field, offshore Vietnam, is comprised of a complex subsurface structure containing stacked reservoir sequences typically found in many other Southeast Asian fields. Combined with areal fault compartmentalization, this situation has led to the observed, large variations in oil properties. Furthermore, the depositional environment in terms of burial history has created a unique overpressure situation which also had an affect, particularly on the crude saturation conditions of individual reservoirs. For commercial and technical reasons, this situation required a detailed analysis, both in terms of variation in crude assay and live oil properties. For whole crude properties: gravity, K factor, wax content and pour point-graphs were drawn up using a large data base of worldwide crudes against which the Dai Hung data could be validated. In case of PVT properties (bubble point and formation volume factor) existing industry correlations were examined. It could be concluded that the sweet, medium gravity and moderately waxy Dai Hung crude has whole crude properties which are comparable to other, similar crudes. The general framework of crude properties established is suitable to type other crudes, even if limited information is available. Of the existing PVT correlations tested, it was found that Standing`s correlation for the oil formation volume factor and the Kartoatmodjo-Schmidt correlation for the bubble point fitted the Dai Hung crude data the best. For the lower shrinkage Dai Hung crudes the Malaysian oil formation volume factor correlation by Omar-Todd gave the best data fit.

  16. Electron contamination modeling and reduction in a 1 T open bore inline MRI-linac system

    SciTech Connect

    Oborn, B. M.; Kolling, S.; Metcalfe, P. E.; Crozier, S.; Litzenberg, D. W.; Keall, P. J.

    2014-05-15

    Purpose: A potential side effect of inline MRI-linac systems is electron contamination focusing causing a high skin dose. In this work, the authors reexamine this prediction for an open bore 1 T MRI system being constructed for the Australian MRI-Linac Program. The efficiency of an electron contamination deflector (ECD) in purging electron contamination from the linac head is modeled, as well as the impact of a helium gas region between the deflector and phantom surface for lowering the amount of air-generated contamination. Methods: Magnetic modeling of the 1 T MRI was used to generate 3D magnetic field maps both with and without the presence of an ECD located immediately below the MLC’s. Forty-seven different ECD designs were modeled and for each the magnetic field map was imported into Geant4 Monte Carlo simulations including the linac head, ECD, and a 30 × 30 × 30 cm{sup 3} water phantom located at isocenter. For the first generation system, the x-ray source to isocenter distance (SID) will be 160 cm, resulting in an 81.2 cm long air gap from the base of the ECD to the phantom surface. The first 71.2 cm was modeled as air or helium gas, with the latter encased between two windows of 50 μm thick high density polyethlyene. 2D skin doses (at 70 μm depth) were calculated across the phantom surface at 1 × 1 mm{sup 2} resolution for 6 MV beams of field size of 5 × 5, 10 × 10, and 20 × 20 cm{sup 2}. Results: The skin dose was predicted to be of similar magnitude as the generic systems modeled in previous work, 230% to 1400% ofD {sub max} for 5 × 5 to 20 × 20 cm{sup 2}, respectively. Inclusion of the ECD introduced a nonuniformity to the MRI imaging field that ranged from ∼20 to ∼140 ppm while the net force acting on the ECD ranged from ∼151 N to ∼1773 N. Various ECD designs were 100% efficient at purging the electron contamination into the ECD magnet banks; however, a small percentage were scattered back into the beam and continued to the phantom

  17. Transient Shock Formation of Pulsed Electrothermal Plasma Discharge Confined in an Extended Bore

    NASA Astrophysics Data System (ADS)

    Kim, Kyoungjin; Kwak, Ho Sang; Park, Joong-Youn

    An electrothermal gun possesses a great potential to be an efficient source of pulsed plasma discharge for nanomaterials production or thermal plasma spray coatings. A plasma discharge by intense pulsed power is numerically studied utilizing time-dependent gas dynamics equations which are solved by FCT (flux-corrected transport) algorithm in two-dimensional domain of the interior capillary bore region and the external region of extended bore. Plasma conditions at the bore exit, mass ablation of polycarbonate bore wall, and degree of ionization are determined at different levels of transient arc current profile. As a way to controlling the plasma discharge, the extended bore at the capillary exit is considered and the flow pattern of pulsed plasma discharge in the extended bore exhibit complex shock structure from slightly to highly underexpanded jet depending on the level of arc current profiles. Flow instability of oscillating Mach disk is found at higher level of arc current profile cases.

  18. Calculation of large scale relative permeabilities from stochastic properties of the permeability field and fluid properties

    SciTech Connect

    Lenormand, R.; Thiele, M.R.

    1997-08-01

    The paper describes the method and presents preliminary results for the calculation of homogenized relative permeabilities using stochastic properties of the permeability field. In heterogeneous media, the spreading of an injected fluid is mainly sue to the permeability heterogeneity and viscosity fingering. At large scale, when the heterogeneous medium is replaced by a homogeneous one, we need to introduce a homogenized (or pseudo) relative permeability to obtain the same spreading. Generally, is derived by using fine-grid numerical simulations (Kyte and Berry). However, this operation is time consuming and cannot be performed for all the meshes of the reservoir. We propose an alternate method which uses the information given by the stochastic properties of the field without any numerical simulation. The method is based on recent developments on homogenized transport equations (the {open_quotes}MHD{close_quotes} equation, Lenormand SPE 30797). The MHD equation accounts for the three basic mechanisms of spreading of the injected fluid: (1) Dispersive spreading due to small scale randomness, characterized by a macrodispersion coefficient D. (2) Convective spreading due to large scale heterogeneities (layers) characterized by a heterogeneity factor H. (3) Viscous fingering characterized by an apparent viscosity ration M. In the paper, we first derive the parameters D and H as functions of variance and correlation length of the permeability field. The results are shown to be in good agreement with fine-grid simulations. The are then derived a function of D, H and M. The main result is that this approach lead to a time dependent . Finally, the calculated are compared to the values derived by history matching using fine-grid numerical simulations.

  19. Theory of bosons in two-leg ladders with large magnetic fields

    NASA Astrophysics Data System (ADS)

    Wei, Ran; Mueller, Erich J.

    2014-06-01

    We calculate the ground state of a Bose gas trapped on a two-leg ladder where Raman-induced hopping mimics the effect of a large magnetic field. In the mean-field limit, where there are large numbers of particles per site, this maps onto a uniformly frustrated two-leg ladder classical spin model. The net particle current always vanishes in the ground state, but generically there is a finite "chiral current," corresponding to equal and opposite flow on the two legs. We vary the strength of the hopping across the rungs of the ladder and the interaction between the bosons. We find the following three phases. (1) A "saturated chiral current phase" (SCCP), where the density is uniform and the chiral current is simply related to the strength of the magnetic field. In this state the only broken symmetry is the U(1) condensate phase. (2) A "biased ladder phase" (BLP), where the density is higher on one leg than the other. The fluid velocity is higher on the lower density leg, so the net current is zero. In addition to the U(1) condensate phase, this has a broken Z2 reflection symmetry. (3) A "modulated density phase" (MDP), where the atomic density is modulated along the ladder. In addition to the U(1) condensate phase, this has a second broken U(1) symmetry corresponding to translations of the density wave. We further study the fluctuations of the condensate in the BLP, finding a roton-maxon-like excitation spectrum. Decreasing the hopping along the rungs softens the spectrum. As the energy of the "roton" reaches to zero, the BLP becomes unstable. We describe the experimental signatures of these phases, including the response to changing the frequency of the Raman transition.

  20. OBSERVATIONS OF ENERGETIC HIGH MAGNETIC FIELD PULSARS WITH THE FERMI LARGE AREA TELESCOPE

    SciTech Connect

    Parent, D.; Abdo, A. A.; Kerr, M.; Den Hartog, P. R.; Romani, R. W.; Watters, K.; Craig, H. A.; Baring, M. G.; DeCesar, M. E.; Harding, A. K.; Espinoza, C. M.; Stappers, B. W.; Weltevrede, P.; Gotthelf, E. V.; Camilo, F.; Johnston, S.; Kaspi, V. M.; Livingstone, M.; Burgay, M.; Freire, P. C. C. E-mail: kerrm@stanford.edu; and others

    2011-12-20

    We report the detection of {gamma}-ray pulsations from the high-magnetic-field rotation-powered pulsar PSR J1119-6127 using data from the Fermi Large Area Telescope. The {gamma}-ray light curve of PSR J1119-6127 shows a single, wide peak offset from the radio peak by 0.43 {+-} 0.02 in phase. Spectral analysis suggests a power law of index 1.0 {+-} 0.3{sup +0.4}{sub -0.2} with an energy cutoff at 0.8 {+-} 0.2{sup +2.0}{sub -0.5} GeV. The first uncertainty is statistical and the second is systematic. We discuss the emission models of PSR J1119-6127 and demonstrate that despite the object's high surface magnetic field-near that of magnetars-the field strength and structure in the {gamma}-ray emitting zone are apparently similar to those of typical young pulsars. Additionally, we present upper limits on the {gamma}-ray pulsed emission for the magnetically active PSR J1846-0258 in the supernova remnant Kesteven 75 and two other energetic high-B pulsars, PSRs J1718-3718 and J1734-3333. We explore possible explanations for the non-detection of these three objects, including peculiarities in their emission geometry.

  1. Current crowding mediated large contact noise in graphene field-effect transistors

    PubMed Central

    Karnatak, Paritosh; Sai, T. Phanindra; Goswami, Srijit; Ghatak, Subhamoy; Kaushal, Sanjeev; Ghosh, Arindam

    2016-01-01

    The impact of the intrinsic time-dependent fluctuations in the electrical resistance at the graphene–metal interface or the contact noise, on the performance of graphene field-effect transistors, can be as adverse as the contact resistance itself, but remains largely unexplored. Here we have investigated the contact noise in graphene field-effect transistors of varying device geometry and contact configuration, with carrier mobility ranging from 5,000 to 80,000 cm2 V−1 s−1. Our phenomenological model for contact noise because of current crowding in purely two-dimensional conductors confirms that the contacts dominate the measured resistance noise in all graphene field-effect transistors in the two-probe or invasive four-probe configurations, and surprisingly, also in nearly noninvasive four-probe (Hall bar) configuration in the high-mobility devices. The microscopic origin of contact noise is directly linked to the fluctuating electrostatic environment of the metal–channel interface, which could be generic to two-dimensional material-based electronic devices. PMID:27929087

  2. Sequential nonadiabatic excitation of large molecules and ions driven by strong laser fields

    SciTech Connect

    Markevitch, Alexei N.; Levis, Robert J.; Romanov, Dmitri A.; Smith, Stanley M.; Schlegel, H. Bernhard; Ivanov, Misha Yu.

    2004-01-01

    Electronic processes leading to dissociative ionization of polyatomic molecules in strong laser fields are investigated experimentally, theoretically, and numerically. Using time-of-flight ion mass spectroscopy, we study the dependence of fragmentation on laser intensity for a series of related molecules and report regular trends in this dependence on the size, symmetry, and electronic structure of a molecule. Based on these data, we develop a model of dissociative ionization of polyatomic molecules in intense laser fields. The model is built on three elements: (i) nonadiabatic population transfer from the ground electronic state to the excited-state manifold via a doorway (charge-transfer) transition; (ii) exponential enhancement of this transition by collective dynamic polarization of all electrons, and (iii) sequential energy deposition in both neutral molecules and resulting molecular ions. The sequential nonadiabatic excitation is accelerated by a counterintuitive increase of a large molecule's polarizability following its ionization. The generic theory of sequential nonadiabatic excitation forms a basis for quantitative description of various nonlinear processes in polyatomic molecules and ions in strong laser fields.

  3. Observations of Energetic High Magnetic Field Pulsars with the Fermi Large Area Telescope

    NASA Technical Reports Server (NTRS)

    Parent, D.; Kerr, M.; DenHartog, P. R.; Baring, M. G.; DeCesar, M. E.; Espinoza, C. M.; Harding, A. K.; Romani, R. W.; Stappers, B. W.; Watters, K.; Weltevrde, P.; Abdo, A. A.; Craig, H. A.; Kramer, M.; Lyne, A. G.

    2011-01-01

    We report the detection of gamma-ray pulsations from the high-magnetic-field rotation-powered pulsar PSR J1119.6127 using data from the Fermi Large Area Telescope. The gamma-ray light curve of PSR J1119.6127 shows a single, wide peak offset from the radio peak by 0.43 +/- 0.02 in phase. Spectral analysis suggests a power law of index 1.0 +/- 0.3(+0.4 -0.2) with an energy cut-off at 0.8 +/- 0.2(+2.0 -0.5) GeV. The first uncertainty is statistical and the second is systematic. We discuss the emission models of PSR J1119.6127 and demonstrate that despite the object's high surface magnetic field--near that of magnetars -- the field strength and structure in the gamma-ray emitting zone are apparently similar to those of typical young pulsars. Additionally, we present upper limits on the gamma-ray pulsed emission for the magnetically active PSR J1846.0258 in the supernova remnant Kesteven 75 and two other energetic high-Beta pulsars, PSRs J1718.3718 and J1734.3333. We explore possible explanations for the non-detection of these three objects, including peculiarities in their emission geometry.

  4. Current crowding mediated large contact noise in graphene field-effect transistors

    NASA Astrophysics Data System (ADS)

    Karnatak, Paritosh; Sai, T. Phanindra; Goswami, Srijit; Ghatak, Subhamoy; Kaushal, Sanjeev; Ghosh, Arindam

    2016-12-01

    The impact of the intrinsic time-dependent fluctuations in the electrical resistance at the graphene-metal interface or the contact noise, on the performance of graphene field-effect transistors, can be as adverse as the contact resistance itself, but remains largely unexplored. Here we have investigated the contact noise in graphene field-effect transistors of varying device geometry and contact configuration, with carrier mobility ranging from 5,000 to 80,000 cm2 V-1 s-1. Our phenomenological model for contact noise because of current crowding in purely two-dimensional conductors confirms that the contacts dominate the measured resistance noise in all graphene field-effect transistors in the two-probe or invasive four-probe configurations, and surprisingly, also in nearly noninvasive four-probe (Hall bar) configuration in the high-mobility devices. The microscopic origin of contact noise is directly linked to the fluctuating electrostatic environment of the metal-channel interface, which could be generic to two-dimensional material-based electronic devices.

  5. On the scaling features of high-latitude geomagnetic field fluctuations during a large geomagnetic storm

    NASA Astrophysics Data System (ADS)

    De Michelis, Paola; Federica Marcucci, Maria; Consolini, Giuseppe

    2015-04-01

    Recently we have investigated the spatial distribution of the scaling features of short-time scale magnetic field fluctuations using measurements from several ground-based geomagnetic observatories distributed in the northern hemisphere. We have found that the scaling features of fluctuations of the horizontal magnetic field component at time scales below 100 minutes are correlated with the geomagnetic activity level and with changes in the currents flowing in the ionosphere. Here, we present a detailed analysis of the dynamical changes of the magnetic field scaling features as a function of the geomagnetic activity level during the well-known large geomagnetic storm occurred on July, 15, 2000 (the Bastille event). The observed dynamical changes are discussed in relationship with the changes of the overall ionospheric polar convection and potential structure as reconstructed using SuperDARN data. This work is supported by the Italian National Program for Antarctic Research (PNRA) - Research Project 2013/AC3.08 and by the European Community's Seventh Framework Programme ([FP7/2007-2013]) under Grant no. 313038/STORM and

  6. Schwinger-Dyson equations in large-N quantum field theories and nonlinear random processes

    SciTech Connect

    Buividovich, P. V.

    2011-02-15

    We propose a stochastic method for solving Schwinger-Dyson equations in large-N quantum field theories. Expectation values of single-trace operators are sampled by stationary probability distributions of the so-called nonlinear random processes. The set of all the histories of such processes corresponds to the set of all planar diagrams in the perturbative expansions of the expectation values of singlet operators. We illustrate the method on examples of the matrix-valued scalar field theory and the Weingarten model of random planar surfaces on the lattice. For theories with compact field variables, such as sigma models or non-Abelian lattice gauge theories, the method does not converge in the physically most interesting weak-coupling limit. In this case one can absorb the divergences into a self-consistent redefinition of expansion parameters. A stochastic solution of the self-consistency conditions can be implemented as a 'memory' of the random process, so that some parameters of the process are estimated from its previous history. We illustrate this idea on the two-dimensional O(N) sigma model. The extension to non-Abelian lattice gauge theories is discussed.

  7. Primordial Magnetic Field Effects on the CMB and Large-Scale Structure

    DOE PAGES

    Yamazaki, Dai G.; Ichiki, Kiyotomo; Kajino, Toshitaka; ...

    2010-01-01

    Mmore » agnetic fields are everywhere in nature, and they play an important role in every astronomical environment which involves the formation of plasma and currents. It is natural therefore to suppose that magnetic fields could be present in the turbulent high-temperature environment of the big bang. Such a primordial magnetic field (PMF) would be expected to manifest itself in the cosmic microwave background (CMB) temperature and polarization anisotropies, and also in the formation of large-scale structure. In this paper, we summarize the theoretical framework which we have developed to calculate the PMF power spectrum to high precision. Using this formulation, we summarize calculations of the effects of a PMF which take accurate quantitative account of the time evolution of the cutoff scale. We review the constructed numerical program, which is without approximation, and an improvement over the approach used in a number of previous works for studying the effect of the PMF on the cosmological perturbations. We demonstrate how the PMF is an important cosmological physical process on small scales. We also summarize the current constraints on the PMF amplitude B λ and the power spectral index n B which have been deduced from the available CMB observational data by using our computational framework.« less

  8. The Effective Field Theory of Large Scale Structures at two loops

    SciTech Connect

    Carrasco, John Joseph M.; Foreman, Simon; Green, Daniel; Senatore, Leonardo E-mail: sfore@stanford.edu E-mail: senatore@stanford.edu

    2014-07-01

    Large scale structure surveys promise to be the next leading probe of cosmological information. It is therefore crucial to reliably predict their observables. The Effective Field Theory of Large Scale Structures (EFTofLSS) provides a manifestly convergent perturbation theory for the weakly non-linear regime of dark matter, where correlation functions are computed in an expansion of the wavenumber k of a mode over the wavenumber associated with the non-linear scale k{sub NL}. Since most of the information is contained at high wavenumbers, it is necessary to compute higher order corrections to correlation functions. After the one-loop correction to the matter power spectrum, we estimate that the next leading one is the two-loop contribution, which we compute here. At this order in k/k{sub NL}, there is only one counterterm in the EFTofLSS that must be included, though this term contributes both at tree-level and in several one-loop diagrams. We also discuss correlation functions involving the velocity and momentum fields. We find that the EFTofLSS prediction at two loops matches to percent accuracy the non-linear matter power spectrum at redshift zero up to k∼ 0.6 h Mpc{sup −1}, requiring just one unknown coefficient that needs to be fit to observations. Given that Standard Perturbation Theory stops converging at redshift zero at k∼ 0.1 h Mpc{sup −1}, our results demonstrate the possibility of accessing a factor of order 200 more dark matter quasi-linear modes than naively expected. If the remaining observational challenges to accessing these modes can be addressed with similar success, our results show that there is tremendous potential for large scale structure surveys to explore the primordial universe.

  9. Traps and attractants for wood-boring insects in ponderosa pine stands in the Black Hills, South Dakota.

    PubMed

    Costello, Sheryl L; Negrón, José F; Jacobi, William R

    2008-04-01

    Recent large-scale wildfires have increased populations of wood-boring insects in the Black Hills of South Dakota. Because little is known about possible impacts of wood-boring insects in the Black Hills, land managers are interested in developing monitoring techniques such as flight trapping with semiochemical baits. Two trap designs and four semiochemical attractants were tested in a recently burned ponderosa pine, Pinus ponderosa Dougl. ex Laws., forest in the Black Hills. Modified panel and funnel traps were tested in combination with the attractants, which included a woodborer standard (ethanol and alpha-pinene), standard plus 3-carene, standard plus ipsenol, and standard plus ipsdienol. We found that funnel traps were equally efficient or more efficient in capturing wood-boring insects than modified panel traps. Trap catches of cerambycids increased when we added the Ips spp. pheromone components (ipsenol or ipsdienol) or the host monoterpene (3-carene) to the woodborer standard. During the summers of 2003 and 2004, 18 cerambycid, 14 buprestid, and five siricid species were collected. One species of cerambycid, Monochamus clamator (LeConte), composed 49 and 40% of the 2003 and 2004 trap catches, respectively. Two other cerambycids, Acanthocinus obliquus (LeConte) and Acmaeops proteus (Kirby), also were frequently collected. Flight trap data indicated that some species were present throughout the summer, whereas others were caught only at the beginning or end of the summer.

  10. On the renormalization of the effective field theory of large scale structures

    SciTech Connect

    Pajer, Enrico; Zaldarriaga, Matias E-mail: matiasz@ias.edu

    2013-08-01

    Standard perturbation theory (SPT) for large-scale matter inhomogeneities is unsatisfactory for at least three reasons: there is no clear expansion parameter since the density contrast is not small on all scales; it does not fully account for deviations at large scales from a perfect pressureless fluid induced by short-scale non-linearities; for generic initial conditions, loop corrections are UV-divergent, making predictions cutoff dependent and hence unphysical. The Effective Field Theory of Large Scale Structures successfully addresses all three issues. Here we focus on the third one and show explicitly that the terms induced by integrating out short scales, neglected in SPT, have exactly the right scale dependence to cancel all UV-divergences at one loop, and this should hold at all loops. A particularly clear example is an Einstein deSitter universe with no-scale initial conditions P{sub in} ∼ k{sup n}. After renormalizing the theory, we use self-similarity to derive a very simple result for the final power spectrum for any n, excluding two-loop corrections and higher. We show how the relative importance of different corrections depends on n. For n ∼ −1.5, relevant for our universe, pressure and dissipative corrections are more important than the two-loop corrections.

  11. Mechanics of Cutting and Boring. Part 7. Dynamics and Energetics of Axial Rotation Machines,

    DTIC Science & Technology

    1981-12-01

    9 5. Measurements of head power as a function of axial thrust for a tunnel boring machine 11 6. Torque and torque force as...functions of axial thrust for a tunnel boring machine ....... 11 7. Maximum working thrust plotted against head diameter for some existing machines...the hole wall, or by the wall, ceiling or floor of a chamber occupied by the boring machine . For deep vertical drilling in rock, the weight of the

  12. Quantitative patterns of large-scale field-aligned currents in the auroral ionosphere

    SciTech Connect

    Foster, J.C.; Fuller-Rowell, T.; Evans, D.S.

    1989-03-01

    Quantitative patterns of the distribution of field-aligned current (FAC) density have been derived from gradients of the average patterns of the Hall and Pedersen currents at high latitudes under the assumption that the total current is divergence-free. The horizontal currents were calculated from empirical convection electric field models, derived from Millstone Hill radar observations, and the ionospheric Hall and Pedersen conductances, based on satellite observations of the precipitating particle energy flux and spectrum and including an average (equinox) solar contribution. These independent empirical models, and the resultant patterns of the field-aligned currents, are keyed to an auroral precipitation index which quantifies the intensity and spatial extent of high-latitude particle precipitation and which is determined from a single satellite crossing of the auroral precipitation pattern. The patterns detail the spatial distribution of the currents as a function of increasing disturbance level. The magnitudes of the total single-hemisphere currents into or out of the ionosphere are closely balanced at each activity level and increase exponentially between 0.1 and 6 MA with increasing values of the precipitation index. The interplanetary magnetic field (IMF) sector dependence of the FAC patterns is investigated for disturbed conditions. A large portion of the FAC pattern is closed by local Pedersen currents (current into the ionosphere is balanced by an equal current out of the ionosphere at that local time). This locally balanced portion of the FAC system is enhanced in the prenoon (postnoon) sector for IMF B/sub v/>+1 nT (B/sub y/<-1 nT). In addition, there are net currents into the ionosphere postnoon and out of the ionosphere in the premidnight sector.

  13. Gun bore flaw image matching based on improved SIFT descriptor

    NASA Astrophysics Data System (ADS)

    Zeng, Luan; Xiong, Wei; Zhai, You

    2013-01-01

    In order to increase the operation speed and matching ability of SIFT algorithm, the SIFT descriptor and matching strategy are improved. First, a method of constructing feature descriptor based on sector area is proposed. By computing the gradients histogram of location bins which are parted into 6 sector areas, a descriptor with 48 dimensions is constituted. It can reduce the dimension of feature vector and decrease the complexity of structuring descriptor. Second, it introduce a strategy that partitions the circular region into 6 identical sector areas starting from the dominate orientation. Consequently, the computational complexity is reduced due to cancellation of rotation operation for the area. The experimental results indicate that comparing with the OpenCV SIFT arithmetic, the average matching speed of the new method increase by about 55.86%. The matching veracity can be increased even under some variation of view point, illumination, rotation, scale and out of focus. The new method got satisfied results in gun bore flaw image matching. Keywords: Metrology, Flaw image matching, Gun bore, Feature descriptor

  14. Bore tube assembly for steam cooling a turbine rotor

    DOEpatents

    DeStefano, Thomas Daniel; Wilson, Ian David

    2002-01-01

    An axial bore tube assembly for a turbine is provided to supply cooling steam to hot gas components of the turbine wheels and return the spent cooling steam. A pair of inner and outer tubes define a steam supply passage concentric about an inner return passage. The forward ends of the tubes communicate with an end cap assembly having sets of peripheral holes communicating with first and second sets of radial tubes whereby cooling steam from the concentric passage is supplied through the end cap holes to radial tubes for cooling the buckets and return steam from the buckets is provided through the second set of radial tubes through a second set of openings of the end cap into the coaxial return passage. A radial-to-axial flow transitioning device, including anti-swirling vanes is provided in the end cap. A strut ring adjacent the aft end of the bore tube assembly permits axial and radial thermal expansion of the inner tube relative to the outer tube.

  15. Large Eddy Simulation of Transonic Flow Field in NASA Rotor 37

    NASA Technical Reports Server (NTRS)

    Hah, Chunill

    2009-01-01

    The current paper reports on numerical investigations on the flow characteristics in a transonic axial compressor, NASA Rotor 37. The flow field was used previously as a CFD blind test case conducted by American Society of Mechanical Engineers in 1994. Since the CFD blind-test exercise, many numerical studies on the flow field in the NASA Rotor 37 have been reported. Although steady improvements have been reported in both numerical procedure and turbulence closure, it is believed that all the important aspects of the flow field have not been fully explained with numerical studies based on the Reynolds Averaged Navier-Stokes (RANS) solution. Experimental data show large dip in total pressure distribution near the hub at downstream of the rotor at 100% rotor speed. Most original numerical solutions from the blind test exercise did not predict this total pressure deficit correctly. This total pressure deficit at the rotor exit was attributed to a hub corner flow separation by the author. Several subsequent numerical studies with different turbulence closure model also calculated this dip in total pressure rise. Also, several studies attributed this total pressure deficit to a small leakage flow coming from the hub in the test article. As the experimental study cannot be repeated, either explanation cannot be validated. The primary purpose of the current investigation is to investigate the transonic flow field with both RANS and a Large Eddy Simulation (LES). The RANS approach gives similar results presented at the original blind test exercise. Although the RANS calculates higher overall total pressure rise, the total pressure deficit near the hub is calculated correctly. The numerical solution shows that the total pressure deficit is due to a hub corner flow separation. The calculated pressure rise from the LES agrees better with the measured total pressure rise especially near the casing area where the passage shock interacts with the tip clearance vortex and flow

  16. Evaluating the vulnerability of bored and driven wells in a shallow unconfined aquifer.

    PubMed

    Schmalzried, Hans; Keil, Charles

    2008-11-01

    Shallow unconfined aquifers are the only source of water for private wells in some rural areas. The Oak Openings region of Ohio is one such location. Wells are usually bored or driven in shallow aquifers and are more susceptible to contamination caused by human activities on the surface. To provide better protection for consumers developing shallow wells, local health departments have doubled the required minimum 50 feet distance for isolation from sources of contamination. The potential for contamination still exists, however. Over a two year period, 42 wells were tested in the region for a large suite of pesticides and inorganic chemicals. Results showed little evidence of persistent contamination. Data provided evidence, however, indicating that these wells are vulnerable. Sodium and chloride concentrations were higher in wells at households with water softeners, illustrating the potential for contaminant transport even with increased isolation distances. To ensure public health, regular monitoring of shallow wells is recommended.

  17. The origin of bore-core remanences: mechanical-shock-imposed irreversible magnetizations

    NASA Astrophysics Data System (ADS)

    Shi, H.; Tarling, D. H.

    1999-06-01

    Repeated laboratory-induced weak mechanical shocking (c. 0.57 kg m s^- ^1 ) of marine sandstone samples showing drilling-induced remanence, from commercial bore cores from the North Sea and Prudhoe Bay, causes increases in their low-field susceptibility (chi) and their ability to acquire an isothermal remanent magnetization (IRM). These enhancements are reduced by some 20 per cent by AF demagnetization in 100 mT. Doubling the intensity of the shock doubles the susceptibilities and IRMs acquired. The susceptibility increase ceases after 300 to 400 shocks for the North Sea samples and 20 to 30 shocks for those from Prudhoe Bay, while the IRM saturates after 800-1000 and 30-50 shocks respectively. Continental, haematite-bearing sandstones from commercial bore cores with no drilling-induced remanence subjected to the same shocks do not show these effects. Differences in the magnetic mineralogy of shocked and unshocked marine samples suggest that the magnetic enhancement is predominantly due to the creation of pyrrhotite by shock-induced irreversible crystallographic changes in iron-bearing sulphides. When shocked during commercial drilling, these new ferromagnetic minerals acquire strong chemical (crystalline) remanences, associated with a wide spectrum of grain sizes, in the magnetic field of the drill string, and these are resistant to both thermal and AF demagnetization. Similar processes are likely in any situation involving the shock of physically metastable iron-bearing minerals, particularly anoxic sediments. A 5 cm non-magnetic collar between the drill stem and crown should drastically reduce the magnetic intensity of this effect under commercial conditions, but would not prevent its occurrence.

  18. Radial transport of large-scale magnetic fields in accretion disks. I. Steady solutions and an upper limit on the vertical field strength

    SciTech Connect

    Okuzumi, Satoshi; Takeuchi, Taku; Muto, Takayuki

    2014-04-20

    Large-scale magnetic fields are key ingredients of magnetically driven disk accretion. We study how large-scale poloidal fields evolve in accretion disks, with the primary aim of quantifying the viability of magnetic accretion mechanisms in protoplanetary disks. We employ a kinematic mean-field model for poloidal field transport and focus on steady states where inward advection of a field balances with outward diffusion due to effective resistivities. We analytically derive the steady-state radial distribution of poloidal fields in highly conducting accretion disks. The analytic solution reveals an upper limit on the strength of large-scale vertical fields attainable in steady states. Any excess poloidal field will diffuse away within a finite time, and we demonstrate this with time-dependent numerical calculations of the mean-field equations. We apply this upper limit to large-scale vertical fields threading protoplanetary disks. We find that the maximum attainable strength is about 0.1 G at 1 AU, and about 1 mG at 10 AU from the central star. When combined with recent magnetic accretion models, the maximum field strength translates into the maximum steady-state accretion rate of ∼10{sup –7} M {sub ☉} yr{sup –1}, in agreement with observations. We also find that the maximum field strength is ∼1 kG at the surface of the central star provided that the disk extends down to the stellar surface. This implies that any excess stellar poloidal field of strength ≳ kG can be transported to the surrounding disk. This might in part resolve the magnetic flux problem in star formation.

  19. The trispectrum in the Effective Field Theory of Large Scale Structure

    NASA Astrophysics Data System (ADS)

    Bertolini, Daniele; Schutz, Katelin; Solon, Mikhail P.; Zurek, Kathryn M.

    2016-06-01

    We compute the connected four point correlation function (the trispectrum in Fourier space) of cosmological density perturbations at one-loop order in Standard Perturbation Theory (SPT) and the Effective Field Theory of Large Scale Structure (EFT of LSS). This paper is a companion to our earlier work on the non-Gaussian covariance of the matter power spectrum, which corresponds to a particular wavenumber configuration of the trispectrum. In the present calculation, we highlight and clarify some of the subtle aspects of the EFT framework that arise at third order in perturbation theory for general wavenumber configurations of the trispectrum. We consistently incorporate vorticity and non-locality in time into the EFT counterterms and lay out a complete basis of building blocks for the stress tensor. We show predictions for the one-loop SPT trispectrum and the EFT contributions, focusing on configurations which have particular relevance for using LSS to constrain primordial non-Gaussianity.

  20. Magnetic Field Effects on the CMB and Large-Scale Structure

    NASA Astrophysics Data System (ADS)

    Yamazaki, Dai G.; Ichiki, Kiyotomo; Kajino, Toshitaka; Mathews, Grant. J.

    2010-08-01

    A primordial magnetic field (PMF) would be expected to manifest itself in the cosmic microwave background (CMB) temperature and polarization anisotropies, and also in the formation of large scale structure(LSS). In this article, we demonstrate how the PMF is an important cosmological physical process on small scales as follows, We also report the newest constraints on the PMF amplitude Bλ and the power spectral index nB which have been deduced from the available CMB observational data by using our computational framework and the Markov chain Monte Carlo method. In particular we find that |Bλ|<2.10(68%CL) nG and < 2.98(95%CL) nG and nB<-1.19(68%CL) and <-0.25(95%CL) at a present scale of 1 Mpc.

  1. Spin dephasing in a magnetic dipole field around large capillaries: Approximative and exact results.

    PubMed

    Kurz, F T; Buschle, L R; Kampf, T; Zhang, K; Schlemmer, H P; Heiland, S; Bendszus, M; Ziener, C H

    2016-12-01

    We present an analytical solution of the Bloch-Torrey equation for local spin dephasing in the magnetic dipole field around a capillary and for ensembles of capillaries, and adapt this solution for the study of spin dephasing around large capillaries. In addition, we provide a rigorous mathematical derivation of the slow diffusion approximation for the spin-bearing particles that is used in this regime. We further show that, in analogy to the local magnetization, the transverse magnetization of one MR imaging voxel in the regime of static dephasing (where diffusion effects are not considered) is merely the first term of a series expansion that constitutes the signal in the slow diffusion approximation. Theoretical results are in agreement with experimental data for capillaries in rat muscle at 7T.

  2. Spin dephasing in a magnetic dipole field around large capillaries: Approximative and exact results

    NASA Astrophysics Data System (ADS)

    Kurz, F. T.; Buschle, L. R.; Kampf, T.; Zhang, K.; Schlemmer, H. P.; Heiland, S.; Bendszus, M.; Ziener, C. H.

    2016-12-01

    We present an analytical solution of the Bloch-Torrey equation for local spin dephasing in the magnetic dipole field around a capillary and for ensembles of capillaries, and adapt this solution for the study of spin dephasing around large capillaries. In addition, we provide a rigorous mathematical derivation of the slow diffusion approximation for the spin-bearing particles that is used in this regime. We further show that, in analogy to the local magnetization, the transverse magnetization of one MR imaging voxel in the regime of static dephasing (where diffusion effects are not considered) is merely the first term of a series expansion that constitutes the signal in the slow diffusion approximation. Theoretical results are in agreement with experimental data for capillaries in rat muscle at 7 T.

  3. Cooldown performance of an inner vertical field coil for the Large Helical Device

    SciTech Connect

    Takahata, K.; Mito, T.; Satow, T.

    1996-07-01

    A single cooldown test of an Inner Vertical (IV) field coil for the Large Helical Device (LHD) was started on February 1 of 1995, and the superconducting transition of the coil was confirmed on February 23. The coil is a forced-flow type using a cable-in-conduit (CIC) conductor and weighing about 16 tons. The total cooldown time was about 250 hours, not including suspended time. Pressure drop characteristics were measured during the cooldown, and the same results were obtained as the R and D coil previously tested. The cooldown time could be reduced by indirect cooling using stainless steel sleeves with cooling pipes. The indirect cooling is effective for the CIC conductor which has no subchannel because otherwise an adequate mass flow cannot be obtained due to a high pressure drop in the high temperature region. The temperature distribution in the vertical direction was also examined during the indirect cooling.

  4. Accidents at Work and Costs Analysis: A Field Study in a Large Italian Company

    PubMed Central

    BATTAGLIA, Massimo; FREY, Marco; PASSETTI, Emilio

    2014-01-01

    Accidents at work are still a heavy burden in social and economic terms, and action to improve health and safety standards at work offers great potential gains not only to employers, but also to individuals and society as a whole. However, companies often are not interested to measure the costs of accidents even if cost information may facilitate preventive occupational health and safety management initiatives. The field study, carried out in a large Italian company, illustrates technical and organisational aspects associated with the implementation of an accident costs analysis tool. The results indicate that the implementation (and the use) of the tool requires a considerable commitment by the company, that accident costs analysis should serve to reinforce the importance of health and safety prevention and that the economic dimension of accidents is substantial. The study also suggests practical ways to facilitate the implementation and the moral acceptance of the accounting technology. PMID:24869894

  5. Biodegradation of marine surface floating crude oil in a large-scale field simulated experiment.

    PubMed

    Bao, Mutai; Sun, Peiyan; Yang, Xiaofei; Wang, Xinping; Wang, Lina; Cao, Lixin; Li, Fujuan

    2014-08-01

    Biodegradation of marine surface floating crude oil with hydrocarbon degrading bacteria, rhamnolipid biosurfactants, and nutrients was carried out by a large-scale field simulated experiment in this paper. After a 103 day experiment, for n-alkanes, the maximum biodegradation rate reached 71% and the results showed hydrocarbon degrading bacteria, rhamnolipid biosurfactants, and nutrients have a comprehensive effect. It also showed that rhamnolipid biosurfactants could shorten the biodegradation time through an emulsifying function; the nutrients could greatly increase the biodegradation rate by promoting HDB production. For PAHs, the chrysene series had higher weathering resistance. For the same series, the weathering resistance ability is C1- < C2- < C3- < C4-. After 53 days, no comprehensive effect occurred and more biodegradation was found for different n-alkanes in two pools which only had added rhamnolipid biosurfactants or nutrients, respectively. Except for C14, C15 and C16 sesquiterpanes, most of the steranes and terpanes had high antibiodegradability.

  6. Accidents at work and costs analysis: a field study in a large Italian company.

    PubMed

    Battaglia, Massimo; Frey, Marco; Passetti, Emilio

    2014-01-01

    Accidents at work are still a heavy burden in social and economic terms, and action to improve health and safety standards at work offers great potential gains not only to employers, but also to individuals and society as a whole. However, companies often are not interested to measure the costs of accidents even if cost information may facilitate preventive occupational health and safety management initiatives. The field study, carried out in a large Italian company, illustrates technical and organisational aspects associated with the implementation of an accident costs analysis tool. The results indicate that the implementation (and the use) of the tool requires a considerable commitment by the company, that accident costs analysis should serve to reinforce the importance of health and safety prevention and that the economic dimension of accidents is substantial. The study also suggests practical ways to facilitate the implementation and the moral acceptance of the accounting technology.

  7. Single high dose-large field irradiation in drug resistant non-Hodgkin's lymphoma

    SciTech Connect

    Scarantino, C.W.; Greven, K.M.; Buss, D.H.

    1988-05-01

    Single high dose-large field irradiation (SHD-LFI), also described as half-body irradiation (HBI), has previously been reported as an effective modality for the palliation of symptoms in a number of solid tumors. This report concerns the ability of SHD-LFI to produce palliation of symptoms and/or objective response in patients with drug resistant non-Hodgkin's lymphoma (NHL). From 1981 to 1984, 34 patients with advanced drug resistant NHL were treated with SHD-LFI either to the whole abdomen (24 patients) or to the upper half body (10 patients). Overall, 19 of 23 patients achieved symptomatic improvement, while objective response was noted in 23 of 30 patients. We noted subjective and objective response in all histologies, and duration of response was not significantly different. Our results suggest a beneficial role for the early and judicious use of SHD-LFI in NHL.

  8. Large-scale magnetic field generation by randomly forced shearing waves.

    PubMed

    Heinemann, T; McWilliams, J C; Schekochihin, A A

    2011-12-16

    A rigorous theory for the generation of a large-scale magnetic field by random nonhelically forced motions of a conducting fluid combined with a linear shear is presented in the analytically tractable limit of low magnetic Reynolds number (Rm) and weak shear. The dynamo is kinematic and due to fluctuations in the net (volume-averaged) electromotive force. This is a minimal proof-of-concept quasilinear calculation aiming to put the shear dynamo, a new effect recently found in numerical experiments, on a firm theoretical footing. Numerically observed scalings of the wave number and growth rate of the fastest-growing mode, previously not understood, are derived analytically. The simplicity of the model suggests that shear dynamo action may be a generic property of sheared magnetohydrodynamic turbulence.

  9. Large Field of View PIV Measurements of Air Entrainment by SLS SMAT Water Sound Suppression System

    NASA Astrophysics Data System (ADS)

    Stegmeir, Matthew; Pothos, Stamatios; Bissell, Dan

    2015-11-01

    Water-based sound suppressions systems have been used to reduce the acoustic impact of space vehicle launches. Water flows at a high rate during launch in order to suppress Engine Generated Acoustics and other potentially damaging sources of noise. For the Space Shuttle, peak flow rates exceeded 900,000 gallons per minute. Such large water flow rates have the potential to induce substantial entrainment of the surrounding air, affecting the launch conditions and generating airflow around the launch vehicle. Validation testing is necessary to quantify this impact for future space launch systems. In this study, PIV measurements were performed to map the flow field above the SMAT sub-scale launch vehicle scaled launch stand. Air entrainment effects generated by a water-based sound suppression system were studied. Mean and fluctuating fluid velocities were mapped up to 1m above the test stand deck and compared to simulation results. Measurements performed with NASA MSFC.

  10. Large developing receptive fields using a distributed and locally reprogrammable address-event receiver.

    PubMed

    Bamford, Simeon A; Murray, Alan F; Willshaw, David J

    2010-02-01

    A distributed and locally reprogrammable address-event receiver has been designed, in which incoming address-events are monitored simultaneously by all synapses, allowing for arbitrarily large axonal fan-out without reducing channel capacity. Synapses can change the address of their presynaptic neuron, allowing the distributed implementation of a biologically realistic learning rule, with both synapse formation and elimination (synaptic rewiring). Probabilistic synapse formation leads to topographic map development, made possible by a cross-chip current-mode calculation of Euclidean distance. As well as synaptic plasticity in rewiring, synapses change weights using a competitive Hebbian learning rule (spike-timing-dependent plasticity). The weight plasticity allows receptive fields to be modified based on spatio-temporal correlations in the inputs, and the rewiring plasticity allows these modifications to become embedded in the network topology.

  11. Two-field Kaehler moduli inflation in large volume moduli stabilization

    SciTech Connect

    Yang, Huan-Xiong; Ma, Hong-Liang E-mail: hlma@mail.ustc.edu.cn

    2008-08-15

    In this paper we present a two-field inflation model, which is distinctive in having a non-canonical kinetic Lagrangian and comes from the large volume approach to the moduli stabilization in flux compactification of type IIB superstring on a Calabi-Yau orientifold with h{sup (1,2)}>h{sup (1,1)}{>=}4. The Kaehler moduli are classified as the volume modulus, heavy moduli and two light moduli. The axion-dilaton, complex structure moduli and all heavy Kaehler moduli including the volume modulus are frozen by a non-perturbatively corrected flux superpotential and the {alpha}{sup '}-corrected Kaehler potential in the large volume limit. The minimum of the scalar potential at which the heavy moduli are stabilized provides the dominant potential energy for the surviving light Kaehler moduli. We consider a simplified case where the axionic components in the light Kaehler moduli are further stabilized at the potential minimum and only the geometrical components are taken as scalar fields to drive an assisted-like inflation. For a certain range of moduli stabilization parameters and inflation initial conditions, we obtain a nearly flat power spectrum of the curvature perturbation, with n{sub s} Almost-Equal-To 0.96 at Hubble exit, and an inflationary energy scale of 3 Multiplication-Sign 10{sup 14} GeV. In our model, there is significant correlation between the curvature and isocurvature perturbations on super-Hubble scales, so at the end of inflation a great deal of the curvature power spectrum originates from this correlation.

  12. A Washington Photometric Survey of the Large Magellanic Cloud Field Star Population

    NASA Astrophysics Data System (ADS)

    Piatti, Andrés E.; Geisler, Doug; Mateluna, Renee

    2012-10-01

    We present photometry for an unprecedented database of some 5.5 million stars distributed throughout the Large Magellanic Cloud main body, from 21 fields covering a total area of 7.6 deg2, obtained from Washington CT 1 T 2 CTIO 4 m MOSAIC data. Extensive artificial star tests over the whole mosaic image data set and the observed behavior of the photometric errors with magnitude demonstrate the accuracy of the morphology and clearly delineate the position of the main features in the color-magnitude diagrams (CMDs). The representative T 1(MS TO) mags are on average ~0.5 mag brighter than the T 1 mags for the 100% completeness level of the respective field, allowing us to derive an accurate age estimate. We have analyzed the CMD Hess diagrams and used the peaks in star counts at the main sequence turnoff and red clump (RC) locations to age date the most dominant sub-population (or "representative" population) in the stellar population mix. The metallicity of this representative population is estimated from the locus of the most populous red giant branch track. We use these results to derive age and metallicity estimates for all of our fields. The analyzed fields span age and metallicity ranges covering most of the galaxy's lifetime and chemical enrichment, i.e., ages and metallicities between ~1 and 13 Gyr and ~-0.2 and -1.2 dex, respectively. We show that the dispersions associated with the mean ages and metallicities represent in general a satisfactory estimate of the age/metallicity spread (~1-3 Gyr/0.2-0.3 dex), although a few subfields have a slightly larger age/metallicity spread. Finally, we revisit the study of the vertical structure (VS) phenomenon, a striking feature composed of stars that extend from the bottom, bluest end of the RC to ~0.45 mag fainter. We confirm that the VS phenomenon is not clearly seen in most of the studied fields and suggest that its occurrence is linked to some other condition(s) in addition to the appropriate age, metallicity, and

  13. Wrong detection of ventricular fibrillation in an implantable cardioverter defibrillator caused by the movement near the MRI scanner bore.

    PubMed

    Mattei, Eugenio; Censi, Federica; Triventi, Michele; Mancini, Matteo; Napolitano, Antonio; Genovese, Elisabetta; Cannata, Vittorio; Falsaperla, Rosaria; Calcagnini, Giovanni

    2015-01-01

    The static magnetic field generated by MRI systems is highly non-homogenous and rapidly decreases when moving away from the bore of the scanner. Consequently, the movement around the MRI scanner is equivalent to an exposure to a time-varying magnetic field at very low frequency (few Hz). For patients with an implanted cardiac stimulators, such as an implantable cardioverter/defibrillator (ICD), the movements inside the MRI environment may thus induce voltages on the loop formed by the leads of the device, with the potential to affect the behavior of the stimulator. In particular, the ICD's detection algorithms may be affected by the induced voltage and may cause inappropriate sensing, arrhythmia detections, and eventually inappropriate ICD therapy.We performed in-vitro measurements on a saline-filled humanshaped phantom (male, 170 cm height), equipped with an MRconditional ICD able to transmit in real-time the detected cardiac activity (electrograms). A biventricular implant was reproduced and the ICD was programmed in standard operating conditions, but with the shock delivery disabled. The electrograms recorded in the atrial, left and right ventricle channels were monitored during rotational movements along the vertical axis, in close proximity of the bore. The phantom was also equipped with an accelerometer and a magnetic field probe to measure the angular velocity and the magnetic field variation during the experiment. Pacing inhibition, inappropriate detection of tachyarrhythmias and of ventricular fibrillation were observed. Pacing inhibition began at an angular velocity of about 7 rad/s, (dB/dt of about 2 T/s). Inappropriate detection of ventricular fibrillation occurred at about 8 rad/s (dB/dt of about 3 T/s). These findings highlight the need for a specific risk assessment of workers with MR-conditional ICDs, which takes into account also effects that are generally not considered relevant for patients, such as the movement around the scanner bore.

  14. Characterizing and calibrating a large Helmholtz coil at low ac magnetic field levels with peak magnitudes below the earth's magnetic field

    NASA Astrophysics Data System (ADS)

    Schill, Robert A.; Hoff, Karin

    2001-06-01

    Characterizing and calibrating a low impedance large Helmholtz coil generating 60 Hz magnetic fields with amplitudes well below the earth's magnetic field is difficult and imprecise when coil shielding is not available and noise is an issue. Parameters influencing the calibration process such as temperature and coil impedance need to be figured in the calibration process. A simple and reliable calibration technique is developed and used to measure low amplitude fields over a spatial grid using a standard Hall effect probe gaussmeter. These low amplitude fields are typically hard or impossible to detect in the presence of background fields when using the gaussmeter in the conventional manner. Standard deviations of two milligauss and less have been achieved over a spatial grid in a uniform field region. Theoretical and measured fields are compared yielding reasonable agreement for a large coil system designed and built for bioelectromagnetic experiments at the University of Nevada at Las Vegas using simple tools. Theoretical results need to be compared with and adjusted in accord with measurements taken over a large parameter space within the design constraints of the coil. Magnetic field measurements made over a four year period are shown to be consistent. Characterizing and calibrating large Helmholtz coils can be performed with rulers, levels, plumb lines, and inexpensive gaussmeters.

  15. Fish navigation of large dams emerges from their modulation of flow field experience

    PubMed Central

    Goodwin, R. Andrew; Politano, Marcela; Garvin, Justin W.; Nestler, John M.; Hay, Duncan; Anderson, James J.; Weber, Larry J.; Dimperio, Eric; Smith, David L.; Timko, Mark

    2014-01-01

    Navigating obstacles is innate to fish in rivers, but fragmentation of the world’s rivers by more than 50,000 large dams threatens many of the fish migrations these waterways support. One limitation to mitigating the impacts of dams on fish is that we have a poor understanding of why some fish enter routes engineered for their safe travel around the dam but others pass through more dangerous routes. To understand fish movement through hydropower dam environments, we combine a computational fluid dynamics model of the flow field at a dam and a behavioral model in which simulated fish adjust swim orientation and speed to modulate their experience to water acceleration and pressure (depth). We fit the model to data on the passage of juvenile Pacific salmonids (Oncorhynchus spp.) at seven dams in the Columbia/Snake River system. Our findings from reproducing observed fish movement and passage patterns across 47 flow field conditions sampled over 14 y emphasize the role of experience and perception in the decision making of animals that can inform opportunities and limitations in living resources management and engineering design. PMID:24706826

  16. Resonant Scanning with Large Field of View Reduces Photobleaching and Enhances Fluorescence Yield in STED Microscopy

    NASA Astrophysics Data System (ADS)

    Wu, Yong; Wu, Xundong; Lu, Rong; Zhang, Jin; Toro, Ligia; Stefani, Enrico

    2015-10-01

    Photobleaching is a major limitation of superresolution Stimulated Depletion Emission (STED) microscopy. Fast scanning has long been considered an effective means to reduce photobleaching in fluorescence microscopy, but a careful quantitative study of this issue is missing. In this paper, we show that the photobleaching rate in STED microscopy can be slowed down and the fluorescence yield be enhanced by scanning with high speed, enabled by using large field of view in a custom-built resonant-scanning STED microscope. The effect of scanning speed on photobleaching and fluorescence yield is more remarkable at higher levels of depletion laser irradiance, and virtually disappears in conventional confocal microscopy. With ≥6 GW•cm-2 depletion irradiance, we were able to extend the fluorophore survival time of Atto 647N and Abberior STAR 635P by ~80% with 8-fold wider field of view. We confirm that STED Photobleaching is primarily caused by the depletion light acting upon the excited fluorophores. Experimental data agree with a theoretical model. Our results encourage further increasing the linear scanning speed for photobleaching reduction in STED microscopy.

  17. Curling probe measurement of large-volume pulsed plasma confined by surface magnetic field

    NASA Astrophysics Data System (ADS)

    Pandey, Anil; Sakakibara, Wataru; Matsuoka, Hiroyuki; Nakamura, Keiji; Sugai, Hideo; Chubu University Team; DOWA Thermotech Collaboration

    2015-09-01

    Curling probe (CP) has recently been developed which enables the local electron density measurement even in plasma for non-conducting film CVD. The electron density is obtained from a shift of resonance frequency of spiral antenna in discharge ON and OFF monitored by a network analyzer (NWA). In case of a pulsed glow discharge, synchronization of discharge pulse with frequency sweep of NWA must be established. In this paper, we report time and space-resolved CP measurement of electron density in a large volume plasma (80 cm diameter, 110 cm length) confined by surface magnetic field (multipole cusp field ~0.03 T). For plasma-aided modification of metal surface, the plasma is produced by 1 kV glow discharge at pulse frequency of 0.3 - 25 kHz with various duty ratio in gas (Ar, N2, C2H2) at pressure ~ 1 Pa. A radially movable CP revealed a remarkable effect of surface magnetic confinement: detach of plasma from the vessel wall and a fairly uniform plasma in the central region. In afterglow phase, the electron density was observed to decrease much faster in C2H2 discharge than in Ar discharge.

  18. Measurement and modeling of polarized specular neutron reflectivity in large magnetic fields

    DOE PAGES

    Maranville, Brian B.; Kirby, Brian J.; Grutter, Alexander J.; ...

    2016-06-09

    The presence of a large applied magnetic field removes the degeneracy of the vacuum energy states for spin-up and spin-down neutrons. For polarized neutron reflectometry, this must be included in the reference potential energy of the Schrödinger equation that is used to calculate the expected scattering from a magnetic layered structure. For samples with magnetization that is purely parallel or antiparallel to the applied field which defines the quantization axis, there is no mixing of the spin states (no spin-flip scattering) and so this additional potential is constant throughout the scattering region. When there is non-collinear magnetization in the sample,more » however, there will be significant scattering from one spin state into the other, and the reference potentials will differ between the incoming and outgoing wavefunctions, changing the angle and intensities of the scattering. In conclusion, the theory of the scattering and recommended experimental practices for this type of measurement are presented, as well as an example measurement.« less

  19. Single-field consistency relations of large scale structure part II: resummation and redshift space

    SciTech Connect

    Creminelli, Paolo; Gleyzes, Jérôme; Vernizzi, Filippo; Simonović, Marko E-mail: jerome.gleyzes@cea.fr E-mail: filippo.vernizzi@cea.fr

    2014-02-01

    We generalize the recently derived single-field consistency relations of Large Scale Structure in two directions. First, we treat the effect of the long modes (with momentum q) on the short ones (with momentum k) non-perturbatively, by writing resummed consistency relations which do not require k/q⋅δ{sub q} << 1. These relations do not make any assumptions on the short-scales physics and are extended to include (an arbitrary number of) multiple long modes, internal lines with soft momenta and soft loops. We do several checks of these relations in perturbation theory and we verify that the effect of soft modes always cancels out in equal-time correlators. Second, we write the relations directly in redshift space, without assuming the single-stream approximation: not only the long mode affects the short scales as a homogeneous gravitational field, but it also displaces them by its velocity along the line-of-sight. Redshift space consistency relations still vanish when short modes are taken at equal time: an observation of a signal in the squeezed limit would point towards multifield inflation or a violation of the equivalence principle.

  20. Secondary crater fields from 24 large primary craters on Mars: Insights into nearby secondary crater production

    NASA Astrophysics Data System (ADS)

    Robbins, Stuart J.; Hynek, Brian M.

    2011-10-01

    Crater statistics are used across a wide variety of applications on planetary surfaces, one of the most notable being estimating relative and absolute ages of those surfaces. This requires an assumed cratering rate over time and that craters be randomly distributed. Secondary craters - craters that form from the ejecta of an impact event - belie this assumption by creating greater crater density in a local area at a single time, significantly affecting crater statistics. There has been substantial debate over the relative importance of secondary craters, and our findings in this Mars study indicate that these events can be very significant and cannot be ignored when age-dating surfaces. We have analyzed secondary crater fields found close to 24 primary craters on Mars. Among other findings such as terrain control over secondary crater field characteristics, we conclude that a single large impact event (>100 km) can significantly affect crater statistics at the ˜1-5-km-diameter level over a non-trivial fraction of a planetary surface (minimum secondary crater diameters examined were ˜0.9 km; the minimum primary crater diameter was ˜20 km). We also suggest a potential way to avoid significant contamination by the majority of secondary craters that occur close to the primary impact event without the need to manually classify every crater as primary or secondary. Our findings are specific to Mars, but further work may show the patterns are applicable to other solid bodies.

  1. The Lagrangian-space Effective Field Theory of large scale structures

    SciTech Connect

    Porto, Rafael A.; Zaldarriaga, Matias; Senatore, Leonardo E-mail: senatore@stanford.edu

    2014-05-01

    We introduce a Lagrangian-space Effective Field Theory (LEFT) formalism for the study of cosmological large scale structures. Unlike the previous Eulerian-space construction, it is naturally formulated as an effective field theory of extended objects in Lagrangian space. In LEFT the resulting finite size effects are described using a multipole expansion parameterized by a set of time dependent coefficients and organized in powers of the ratio of the wavenumber of interest k over the non-linear scale k{sub NL}. The multipoles encode the effects of the short distance modes on the long-wavelength universe and absorb UV divergences when present. There are no IR divergences in LEFT. Some of the parameters that control the perturbative approach are not assumed to be small and can be automatically resummed. We present an illustrative one-loop calculation for a power law universe. We describe the dynamics both at the level of the equations of motion and through an action formalism.

  2. Measurement and modeling of polarized specular neutron reflectivity in large magnetic fields

    SciTech Connect

    Maranville, Brian B.; Kirby, Brian J.; Grutter, Alexander J.; Kienzle, Paul A.; Majkrzak, Charles F.; Liu, Yaohua; Dennis, Cindi L.

    2016-06-09

    The presence of a large applied magnetic field removes the degeneracy of the vacuum energy states for spin-up and spin-down neutrons. For polarized neutron reflectometry, this must be included in the reference potential energy of the Schrödinger equation that is used to calculate the expected scattering from a magnetic layered structure. For samples with magnetization that is purely parallel or antiparallel to the applied field which defines the quantization axis, there is no mixing of the spin states (no spin-flip scattering) and so this additional potential is constant throughout the scattering region. When there is non-collinear magnetization in the sample, however, there will be significant scattering from one spin state into the other, and the reference potentials will differ between the incoming and outgoing wavefunctions, changing the angle and intensities of the scattering. In conclusion, the theory of the scattering and recommended experimental practices for this type of measurement are presented, as well as an example measurement.

  3. Resonant Scanning with Large Field of View Reduces Photobleaching and Enhances Fluorescence Yield in STED Microscopy

    PubMed Central

    Wu, Yong; Wu, Xundong; Lu, Rong; Zhang, Jin; Toro, Ligia; Stefani, Enrico

    2015-01-01

    Photobleaching is a major limitation of superresolution Stimulated Depletion Emission (STED) microscopy. Fast scanning has long been considered an effective means to reduce photobleaching in fluorescence microscopy, but a careful quantitative study of this issue is missing. In this paper, we show that the photobleaching rate in STED microscopy can be slowed down and the fluorescence yield be enhanced by scanning with high speed, enabled by using large field of view in a custom-built resonant-scanning STED microscope. The effect of scanning speed on photobleaching and fluorescence yield is more remarkable at higher levels of depletion laser irradiance, and virtually disappears in conventional confocal microscopy. With ≥6 GW∙cm−2 depletion irradiance, we were able to extend the fluorophore survival time of Atto 647N and Abberior STAR 635P by ~80% with 8-fold wider field of view. We confirm that STED Photobleaching is primarily caused by the depletion light acting upon the excited fluorophores. Experimental data agree with a theoretical model. Our results encourage further increasing the linear scanning speed for photobleaching reduction in STED microscopy. PMID:26424175

  4. Laws of Large Numbers and Langevin Approximations for Stochastic Neural Field Equations

    PubMed Central

    2013-01-01

    In this study, we consider limit theorems for microscopic stochastic models of neural fields. We show that the Wilson–Cowan equation can be obtained as the limit in uniform convergence on compacts in probability for a sequence of microscopic models when the number of neuron populations distributed in space and the number of neurons per population tend to infinity. This result also allows to obtain limits for qualitatively different stochastic convergence concepts, e.g., convergence in the mean. Further, we present a central limit theorem for the martingale part of the microscopic models which, suitably re-scaled, converges to a centred Gaussian process with independent increments. These two results provide the basis for presenting the neural field Langevin equation, a stochastic differential equation taking values in a Hilbert space, which is the infinite-dimensional analogue of the chemical Langevin equation in the present setting. On a technical level, we apply recently developed law of large numbers and central limit theorems for piecewise deterministic processes taking values in Hilbert spaces to a master equation formulation of stochastic neuronal network models. These theorems are valid for processes taking values in Hilbert spaces, and by this are able to incorporate spatial structures of the underlying model. Mathematics Subject Classification (2000): 60F05, 60J25, 60J75, 92C20. PMID:23343328

  5. On the velocity in the Effective Field Theory of Large Scale Structures

    SciTech Connect

    Mercolli, Lorenzo; Pajer, Enrico E-mail: enrico.pajer@gmail.com

    2014-03-01

    We compute the renormalized two-point functions of density, divergence and vorticity of the velocity in the Effective Field Theory of Large Scale Structures. Because of momentum and mass conservation, the corrections from short scales to the large-scale power spectra of density, divergence and vorticity must start at order k{sup 4}. For the vorticity this constitutes one of the two leading terms. Exact (approximated) self-similarity of an Einstein-de Sitter (ΛCDM) background fixes the time dependence so that the vorticity power spectrum at leading order is determined by the symmetries of the problem and the power spectrum around the non-linear scale. We show that to cancel all divergences in the velocity correlators one needs new counterterms. These fix the definition of velocity and do not represent new properties of the system. For an Einstein-de Sitter universe, we show that all three renormalized cross- and auto-correlation functions have the same structure but different numerical coefficients, which we compute. We elucidate the differences between using momentum and velocity.

  6. Fencing in the swampland: quantum gravity constraints on large field inflation

    NASA Astrophysics Data System (ADS)

    Brown, Jon; Cottrell, William; Shiu, Gary; Soler, Pablo

    2015-10-01

    In this note we show that models of natural inflation based on closed string axions are incompatible with the weak gravity conjecture (WGC). Specifically, we use T- duality in order to map the bounds on the charge-to-mass ratio of particles imposed by the WGC, to constraints on the ratio between instanton actions and axion decay constants. We use this connection to prove that if the WGC holds, even when multiple axions are present and mix with each other, one cannot have large axion decay constants while remaining in a regime of perturbative control. We also discuss the extension of the WGC to discrete symmetries and its possible impact on models with axion monodromy, and the distinction between the strong and mild versions of the WGC. We argue that, if the strong version is violated, the constraints on large field inflation can be evaded while still satisfying the mild one. Finally, we offer some speculations regarding the import of these results to the general theory of inflation.

  7. Large-field-of-view wide-spectrum artificial reflecting superposition compound eyes.

    PubMed

    Huang, Chi-Chieh; Wu, Xiudong; Liu, Hewei; Aldalali, Bader; Rogers, John A; Jiang, Hongrui

    2014-08-13

    In nature, reflecting superposition compound eyes (RSCEs) found in shrimps, lobsters and some other decapods are extraordinary imaging systems with numerous optical features such as minimum chromatic aberration, wide-angle field of view (FOV), high sensitivity to light and superb acuity to motion. Here, we present life-sized, large-FOV, wide-spectrum artificial RSCEs as optical imaging devices inspired by the unique designs of their natural counterparts. Our devices can form real, clear images based on reflection rather than refraction, hence avoiding chromatic aberration due to dispersion by the optical materials. Compared to imaging at visible wavelengths using conventional refractive lenses of comparable size, our artificial RSCEs demonstrate minimum chromatic aberration, exceptional FOV up to 165° without distortion, modest aberrations and comparable imaging quality without any post-image processing. Together with an augmenting cruciform pattern surrounding each focused image, our large-FOV, wide-spectrum artificial RSCEs possess enhanced motion-tracking capability ideal for diverse applications in military, security, medical imaging and astronomy.

  8. Simulating observations with HARMONI: the integral field spectrograph for the European Extremely Large Telescope

    NASA Astrophysics Data System (ADS)

    Zieleniewski, Simon; Thatte, Niranjan; Kendrew, Sarah; Houghton, Ryan; Tecza, Matthias; Clarke, Fraser; Fusco, Thierry; Swinbank, Mark

    2014-07-01

    With the next generation of extremely large telescopes commencing construction, there is an urgent need for detailed quantitative predictions of the scientific observations that these new telescopes will enable. Most of these new telescopes will have adaptive optics fully integrated with the telescope itself, allowing unprecedented spatial resolution combined with enormous sensitivity. However, the adaptive optics point spread function will be strongly wavelength dependent, requiring detailed simulations that accurately model these variations. We have developed a simulation pipeline for the HARMONI integral field spectrograph, a first light instrument for the European Extremely Large Telescope. The simulator takes high-resolution input data-cubes of astrophysical objects and processes them with accurate atmospheric, telescope and instrumental effects, to produce mock observed cubes for chosen observing parameters. The output cubes represent the result of a perfect data reduc- tion process, enabling a detailed analysis and comparison between input and output, showcasing HARMONI's capabilities. The simulations utilise a detailed knowledge of the telescope's wavelength dependent adaptive op- tics point spread function. We discuss the simulation pipeline and present an early example of the pipeline functionality for simulating observations of high redshift galaxies.

  9. Large field-of-view tiled grating structures for X-ray phase-contrast imaging

    NASA Astrophysics Data System (ADS)

    Schröter, Tobias J.; Koch, Frieder J.; Meyer, Pascal; Kunka, Danays; Meiser, Jan; Willer, Konstantin; Gromann, Lukas; De Marco, Fabio; Herzen, Julia; Noel, Peter; Yaroshenko, Andre; Hofmann, Andreas; Pfeiffer, Franz; Mohr, Jürgen

    2017-01-01

    X-ray grating-based interferometry promises unique new diagnostic possibilities in medical imaging and materials analysis. To transfer this method from scientific laboratories or small-animal applications to clinical radiography applications, compact setups with a large field of view (FoV) are required. Currently the FoV is limited by the grating area, which is restricted due to the complex manufacturing process. One possibility to increase the FoV is tiling individual grating tiles to create one large area grating mounted on a carrier substrate. We investigate theoretically the accuracy needed for a tiling process in all degrees of freedom by applying a simulation approach. We show how the resulting precision requirements can be met using a custom-built frame for exact positioning. Precise alignment is achieved by comparing the fringe patterns of two neighboring grating tiles in a grating interferometer. With this method, the FoV can be extended to practically any desired length in one dimension. First results of a phase-contrast scanning setup with a full FoV of 384 mm × 24 mm show the suitability of this method.

  10. A large and complete Jurassic geothermal field at Claudia, Deseado Massif, Santa Cruz, Argentina

    NASA Astrophysics Data System (ADS)

    Guido, Diego M.; Campbell, Kathleen A.

    2014-04-01

    Late Jurassic geothermal deposits at Claudia, Argentinean Patagonia, are among the largest (40 km2) and most varied in the Deseado Massif, a 60,000 km2 volcanic province hosting precious metals (Au, Ag) mineralization generated during diffuse back arc spreading and opening of the South Atlantic Ocean. Both siliceous sinter and travertine occur in the same stratigraphic sequence. Deposits range from those interpreted as fluvially reworked hydrothermal silica gels, to extensive apron terraces, to a clustering of high-temperature subaerial vent mounds. Paleoenvironmentally diagnostic textures of sinters include wavy laminated, bubble mat and nodular fabrics, and for travertines comprise fossil terracette rims, wavy laminated, bubble mat, spherulitic, oncoidal, and peloidal fabrics. Of special note is the presence of relatively large (to 25 cm high), inferred subaqueous "Conophyton" structures in travertines, which serve as analogs for some Precambrian stromatolites and imply the presence of relatively deep pools maintained by voluminous spring discharges. The Claudia geothermal field is geographically and geologically linked to the Cerro Vanguardia epithermal project (total resource of ~ 7.8 million ounces Au equivalent) via proximity, similar veins, and structural linkages, making it an especially large and relevant prospect for the region. The combined Claudia-Cerro Vanguardia hydrothermal system likely represents a fortuitous alignment of focused fluid flow and structure conducive to forming a giant epithermal ore deposit, with respect to size, ore concentration and potentially duration, in the Late Jurassic of Patagonia.

  11. Quantitative field measurement of soot emission from a large gas flare using sky-LOSA.

    PubMed

    Johnson, Matthew R; Devillers, Robin W; Thomson, Kevin A

    2011-01-01

    Particulate matter emissions from unconfined sources such as gas flares are extremely difficult to quantify, yet there is a significant need for this measurement capability due to the prevalence and magnitude of gas flaring worldwide. Current estimates for soot emissions from flares are rarely, if ever, based on any form of direct data. A newly developed method to quantify the mass emission rate of soot from flares is demonstrated on a large-scale flare at a gas plant in Uzbekistan, in what is believed to be the first in situ quantitative measurement of soot emission rate from a gas flare under field conditions. The technique, named sky-LOSA, is based on line-of-sight attenuation of skylight through a flare plume coupled with image correlation velocimetry. Monochromatic plume transmissivities were measured using a thermoelectrically cooled scientific-grade CCD camera. Plume velocities were separately calculated using image correlation velocimetry on high-speed movie data. For the flare considered, the mean soot emission rate was determined to be 2.0 g/s at a calculated uncertainty of 33%. This emission rate is approximately equivalent to that of 500 buses driving continuously and equates to approximately 275 trillion particles per second. The environmental impact of large, visibly sooting flares can be quite significant.

  12. Closed-bore XMR (CBXMR) systems for aortic valve replacement: X-ray tube imaging performance

    SciTech Connect

    Bracken, John A.; Komljenovic, Philip; Lillaney, Prasheel V.; Fahrig, Rebecca; Rowlands, J. A.

    2009-04-15

    A hybrid closed-bore x-ray/MRI system (CBXMR) is proposed to improve the safety and efficacy of percutaneous aortic valve replacement procedures. In this system, an x-ray C-arm will be positioned about 1 m from the entrance of a 1.5 T MRI scanner. The CBXMR system will harness the complementary strengths of both modalities to guide and deploy a bioprosthetic valve into the aortic annulus of the heart without coronary artery obstruction. A major challenge in constructing this system is ensuring proper operation of a rotating-anode x-ray tube in the MRI magnetic fringe field environment. The electron beam in the x-ray tube responsible for producing x rays can be deflected by the fringe field. However, the clinical impact of electron beam deflection in a magnetic field has not yet been studied. Here, the authors investigated changes in focal spot resolving power, field of view shift, and field of view truncation in x-ray images as a result of electron beam deflection. The authors found that in the fringe field acting on the x-ray tube at the clinical location for the x-ray C-arm (4 mT), focal spot size increased by only 2%, so the fringe field did not limit the resolving power of the x-ray system. The magnetic field also caused the field of view to shift by 3 mm. This shift must be corrected to avoid unnecessary primary radiation exposure to the patient and the staff in the cardiac catheterization laboratory. The fringe field was too weak to cause field of view truncation.

  13. Closed-bore XMR (CBXMR) systems for aortic valve replacement: x-ray tube imaging performance.

    PubMed

    Bracken, John A; Komljenovic, Philip; Lillaney, Prasheel V; Fahrig, Rebecca; Rowlands, J A

    2009-04-01

    A hybrid closed-bore x-ray/MRI system (CBXMR) is proposed to improve the safety and efficacy of percutaneous aortic valve replacement procedures. In this system, an x-ray C-arm will be positioned about 1 m from the entrance of a 1.5 T MRI scanner. The CBXMR system will harness the complementary strengths of both modalities to guide and deploy a bioprosthetic valve into the aortic annulus of the heart without coronary artery obstruction. A major challenge in constructing this system is ensuring proper operation of a rotating-anode x-ray tube in the MRI magnetic fringe field environment. The electron beam in the x-ray tube responsible for producing x rays can be deflected by the fringe field. However, the clinical impact of electron beam deflection in a magnetic field has not yet been studied. Here, the authors investigated changes in focal spot resolving power, field of view shift, and field of view truncation in x-ray images as a result of electron beam deflection. The authors found that in the fringe field acting on the x-ray tube at the clinical location for the x-ray C-arm (4 mT), focal spot size increased by only 2%, so the fringe field did not limit the resolving power of the x-ray system. The magnetic field also caused the field of view to shift by 3 mm. This shift must be corrected to avoid unnecessary primary radiation exposure to the patient and the staff in the cardiac catheterization laboratory. The fringe field was too weak to cause field of view truncation.

  14. Study of shape evaluation for mask and silicon using large field of view

    NASA Astrophysics Data System (ADS)

    Matsuoka, Ryoichi; Mito, Hiroaki; Shinoda, Shinichi; Toyoda, Yasutaka

    2010-09-01

    We have developed a highly integrated method of mask and silicon metrology. The aim of this integration is evaluating the performance of the silicon corresponding to Hotspot on a mask. It can use the mask shape of a large field, besides. The method adopts a metrology management system based on DBM (Design Based Metrology). This is the high accurate contouring created by an edge detection algorithm used in mask CD-SEM and silicon CD-SEM. Currently, as semiconductor manufacture moves towards even smaller feature size, this necessitates more aggressive optical proximity correction (OPC) to drive the super-resolution technology (RET). In other words, there is a trade-off between highly precise RET and mask manufacture, and this has a big impact on the semiconductor market that centers on the mask business. As an optimal solution to these issues, we provide a DFM solution that extracts 2-dimensional data for a more realistic and error-free simulation by reproducing accurately the contour of the actual mask, in addition to the simulation results from the mask data. On the other hand, there is roughness in the silicon form made from a mass-production line. Moreover, there is variation in the silicon form. For this reason, quantification of silicon form is important, in order to estimate the performance of a pattern. In order to quantify, the same form is equalized in two dimensions. And the method of evaluating based on the form is popular. In this study, we conducted experiments for averaging method of the pattern (Measurement Based Contouring) as two-dimensional mask and silicon evaluation technique. That is, observation of the identical position of a mask and a silicon was considered. The result proved its detection accuracy and reliability of variability on two-dimensional pattern (mask and silicon) and is adaptable to following fields of mask quality management. •Discrimination of nuisance defects for fine pattern. •Determination of two-dimensional variability of

  15. Large low-field magnetodielectric response in multiferroic Bi2NiMnO6 thin film

    NASA Astrophysics Data System (ADS)

    Rathi, A.; Anshul, Avneesh; Gupta, Anurag; Rout, P. K.; Maurya, K. K.; Kotnala, R. K.; Pant, R. P.; Basheed, G. A.

    2017-04-01

    Single-phase multiferroics exhibiting a large low-field magnetodielectric effect (MDE) are of great interest for the practical realization of multifunctional devices, as existing multiferroics demand large magnetic fields to cause any significant MDE. Here, we report remarkably large MDE \\equiv Δ {{\\varepsilon}\\prime} /{{\\varepsilon}\\prime}∼ 6 % at very low fields (H≤slant 5 kOe) near T C in multiferroic Bi2NiMnO6 thin film. More importantly, the insensitivity of {{\\varepsilon}\\prime} to temperature and frequency variations, and pronounced change in {{\\varepsilon}\\prime} near T C in zero magnetic field attribute the observed large MDE to the inherent exchange magnetoelectric interactions.

  16. Active and passive migration in boring isopods Limnoria spp. (Crustacea, Peracarida) from kelp holdfasts

    NASA Astrophysics Data System (ADS)

    Miranda, Leonardo; Thiel, Martin

    2008-10-01

    Many boring isopods inhabit positively buoyant substrata (wood and algae), which float after detachment, permitting passive migration of inhabitants. Based on observations from previous studies, it was hypothesized that juvenile, subadult and male isopods migrate actively, and will rapidly abandon substrata after detachment. In contrast, reproductive females and small offspring were predicted to remain in floating substrata and thus have a high probability to disperse passively via rafting. In order to test this hypothesis, a colonization and an emigration experiment were conducted with giant kelp ( Macrocystis integrifolia), the holdfasts of which are inhabited by boring isopods from the genus Limnoria. A survey of benthic substrata in the kelp forest confirmed that limnoriids inhabited the holdfasts and did not occur in holdfast-free samples. Results of the colonization experiment showed that all life history stages of the boring isopods immigrated into young, largely uncolonized holdfasts, and after 16 weeks all holdfasts were densely colonized. In the emigration experiment, all life history stages of the isopods rapidly abandoned the detached holdfasts — already 5 min after detachment only few individuals remained in the floating holdfasts. After this initial rapid emigration of isopods, little changes in isopod abundance occurred during the following 24 h, and at the end of the experiment some individuals of all life history stages still remained in the holdfasts. These results indicate that all life history stages of Limnoria participate in both active migration and passive dispersal. It is discussed that storm-related dynamics within kelp forests may contribute to intense mixing of local populations of these burrow-dwelling isopods, and that most immigrants to young holdfasts probably are individuals emigrating from old holdfasts detached during storm events. The fact that some individuals of all life history stages and both sexes remain in floating

  17. Biopolymers under large external forces and mean-field RNA virus evolutionary dynamics

    NASA Astrophysics Data System (ADS)

    Ahsan, Syed Amir

    The modeling of the mechanical response of single-molecules of DNA and RNA under large external forces through statistical mechanical methods is central to this thesis with a small portion devoted to modeling the evolutionary dynamics of positive-sense single-stranded RNA viruses. In order to develop and test models of biopolymer mechanics and illuminate the mechanisms underlying biological processes where biopolymers undergo changes in energy on the order of the thermal energy, , entails measuring forces and lengths on the scale of piconewtons (pN) and nanometers (nm), respectively. A capacity achieved in the past two decades at the single-molecule level through the development of micromanipulation techniques such as magnetic and optical tweezers, atomic force microscopy, coupled with advances in micro- and nanofabrication. The statistical mechanical models of biopolymers developed in this dissertation are dependent upon and the outcome of these advancements and resulting experiments. The dissertation begins in chapter 1 with an introduction to the structure and thermodynamics of DNA and RNA, highlighting the importance and effectiveness of simple, two-state models in their description as a prelude to the emergence of two-state models in the research manuscripts. In chapter 2 the standard models of the elasticity of polymers and of a polymer gel are reviewed, characterizing the continuum and mean-field models, including the scaling behavior of DNA in confined spaces. The research manuscript presented in the last section of chapter 2 (section 2.5), subsequent to a review of a Flory gel and in contrast to it, is a model of the elasticity of RNA as a gel, with viral RNA illustrating an instance of such a network, and shown to exhibit anomalous elastic behavior, a negative Poisson ratio, and capable of facilitating viral RNA encapsidation with further context provided in section 5.1. In chapter 3 the experimental methods and behavior of DNA and RNA under mechanical

  18. Four large-scale field-aligned current systmes in the dayside high-latitude region

    NASA Technical Reports Server (NTRS)

    Ohtani, S.; Potemra, T. A.; Newell, P.T.; Zanetti, L. J.; Iijima, T.; Watanabe, M.; Blomberg, L. G.; Elphinstone, R. D.; Murphree, J. S.; Yamauchi, M.

    1995-01-01

    A system of four current sheets of large-scale field-aligned currents (FACs) was discovered in the data set of simultaneous Viking and Defense Meteorological Satellire Program-F7 (DMSP-F7) crossing of the dayside high-latitude region. This paper reports four examples of this system that were observed in the prenoon sector. The flow polarities of FACs are upward, downward, upward, and downward, from equatorward to poleward. The lowest-latitude upward current is flowing mostly in the central plasma sheet (CPS) precipitation region, often overlapping with the boundary plasma sheet (BPS) at its poleward edge, andis interpreted as a region 2 current. The pair of downward and upward FACs in the middle of te structure are collocated with structured electron precipitation. The precipitation of high-energy (greater than 1 keV) electrons is more intense in the lower-latitude downward current sheet. The highest-latitude downward flowing current sheet is located in a weak, low-energy particle precipitation region, suggesting that this current is flowing on open field lines. Simulaneous observations in the postnoon local time sector reveal the standard three-sheet structure of FACs, sometimes described as region 2, region 1, and mantle (referred to the midday region O) currents. A high correlation was found between the occurrence of the four FAC sheet structure and negative interplanetary magnetic field (IMF) B(sub Y). We discuss the FAC structurein terms of three types of convection cells: the merging, viscous, andlobe cells. During strongly negative IMF B(sub Y), two convection reversals exist in the prenoon sector; one is inside the viscous cell, and the other is between the viscous cell and the lobe cell. This structure of convection flow is supported by the Viking electric field and auroral UV image data. Based on the convection pattern, the four FAC sheet structure is interpreted as the latitude overlap of midday and morning FAC systems. We suggest that the for

  19. Machine vision system for the control of tunnel boring machines

    NASA Astrophysics Data System (ADS)

    Habacher, Michael; O'Leary, Paul; Harker, Matthew; Golser, Johannes

    2013-03-01

    This paper presents a machine vision system for the control of dual-shield Tunnel Boring Machines. The system consists of a camera with ultra bright LED illumination and a target system consisting of multiple retro-reflectors. The camera mounted on the gripper shield measures the relative position and orientation of the target which is mounted on the cutting shield. In this manner the position of the cutting shield relative to the gripper shield is determined. Morphological operators are used to detect the retro-reflectors in the image and a covariance optimized circle fit is used to determine the center point of each reflector. A graph matching algorithm is used to ensure a robust matching of the constellation of the observed target with the ideal target geometry.

  20. Biogeography of Wood-Boring Crustaceans (Isopoda: Limnoriidae) Established in European Coastal Waters

    PubMed Central

    Borges, Luísa M. S.; Merckelbach, Lucas M.; Cragg, Simon M.

    2014-01-01

    Marine wood-borers of the Limnoriidae cause great destruction to wooden structures exposed in the marine environment. In this study we collated occurrence data obtained from field surveys, spanning over a period of 10 years, and from an extensive literature review. We aimed to determine which wood-boring limnoriid species are established in European coastal waters; to map their past and recent distribution in Europe in order to infer species range extension or contraction; to determine species environmental requirements using climatic envelopes. Of the six species of wood-boring Limnoria previously reported occurring in Europe, only Limnoria lignorum, L. quadripunctata and L. tripunctata are established in European coastal waters. L. carinata and L. tuberculata have uncertain established status, whereas L. borealis is not established in European waters. The species with the widest distribution in Europe is Limnoria lignorum, which is also the most tolerant species to a range of salinities. L. quadripunctata and L. tripunctata appear to be stenohaline. However, the present study shows that both L. quadripunctata and L. tripunctata are more widespread in Europe than previous reports suggested. Both species have been found occurring in Europe since they were described, and their increased distribution is probably the results of a range expansion. On the other hand L. lignorum appears to be retreating poleward with ocean warming. In certain areas (e.g. southern England, and southern Portugal), limnoriids appear to be very abundant and their activity is rivalling that of teredinids. Therefore, it is important to monitor the distribution and destructive activity of these organisms in Europe. PMID:25313796

  1. Study on the response of the full-bore conductance sensor for water cut measurement

    NASA Astrophysics Data System (ADS)

    Xie, Ronghua; Liu, Xingbin; Hu, Jinhai; Dai, Xuefei; Shan, Fujun; Xu, Wenfeng

    2009-02-01

    This paper has proposed a new structure of full-bore conductance sensor, which is designed for measuring water cut of the oil-water two-phase flow. The structure of the full-bore conductance sensor and the measurement principle are introduced in the paper. The mental ring-shaped electrode is mounted on the outside wall of the cylindrical insulation body. When the electrode is provided with constant current, according to the electrical theory, the electrode generates a voltage, the value of which is inversely proportional to the conductivity of fluid flowing between the sensor and the casing. The electrostatic field simulations of the sensor are accomplished by using ANSYS software. The results of the potential distribution simulation show that the potential decays quickly from the electrode along r direction (radial) and z direction (axial)to both sides, and the potential only distributes in a very narrow area near the electrode. A series of static experiments on the sensor are carried out in laboratory. The experiment results agree with the simulation results. In radial direction, the closer the rod is to the sensor, the more sensitive the sensor becomes and the greater the relative response becomes. In axial direction, the electrode only responds in a certain region on both sides of the electrode and decays rapidly from the electrode to both sides. And the salinity experiment is conducted in salt solution (3000 ppm), which shows that within the allowable range of experiment error, there is no effect of salinity on the sensor response. response.

  2. On the operation of X-ray polarimeters with a large field of view

    SciTech Connect

    Muleri, Fabio

    2014-02-10

    The measurement of linear polarization is one of the hot topics of high-energy astrophysics. Gas detectors based on the photoelectric effect have paved the way for the design of sensitive instruments, and mission proposals based on them have been presented in the last few years in the energy range from about 2 keV to a few tens of keV. In addition, a number of polarimeters based on Compton scattering are approved or being discussed for launch on board balloons or space satellites at higher energies. These instruments are typically dedicated to pointed observations with narrow field of view telescopes or collimators, but there are also projects aimed at the polarimetry of bright transient sources such as soft gamma repeaters or the prompt emission of gamma-ray bursts. Given the erratic appearance of such events in the sky, these polarimeters have large fields of view to catch a reasonable number of them, and as a result, photons may impinge on the detector off-axis. This dramatically changes the response of the instrument to polarization, regardless of whether photoabsorption or Compton scattering is involved. Instead of the simple cosine-squared dependence expected for polarized photons that are incident on-axis, the response is never purely cosinusoidal, and a systematic modulation also appears for unpolarized radiation. We investigate the origin of these differences and present an analytical treatment that proves that such systematic effects are actually a natural consequence of how current instruments operate. Our analysis provides the expected response of photoelectric or Compton polarimeters to photons impinging with any inclination and state of polarization.

  3. CFD Modelling of Bore Erosion in Two-Stage Light Gas Guns

    NASA Technical Reports Server (NTRS)

    Bogdanoff, D. W.

    1998-01-01

    A well-validated quasi-one-dimensional computational fluid dynamics (CFD) code for the analysis of the internal ballistics of two-stage light gas guns is modified to explicitly calculate the ablation of steel from the gun bore and the incorporation of the ablated wall material into the hydrogen working cas. The modified code is used to model 45 shots made with the NASA Ames 0.5 inch light gas gun over an extremely wide variety of gun operating conditions. Good agreement is found between the experimental and theoretical piston velocities (maximum errors of +/-2% to +/-6%) and maximum powder pressures (maximum errors of +/-10% with good igniters). Overall, the agreement between the experimental and numerically calculated gun erosion values (within a factor of 2) was judged to be reasonably good, considering the complexity of the processes modelled. Experimental muzzle velocities agree very well (maximum errors of 0.5-0.7 km/sec) with theoretical muzzle velocities calculated with loading of the hydrogen gas with the ablated barrel wall material. Comparison of results for pump tube volumes of 100%, 60% and 40% of an initial benchmark value show that, at the higher muzzle velocities, operation at 40% pump tube volume produces much lower hydrogen loading and gun erosion and substantially lower maximum pressures in the gun. Large muzzle velocity gains (2.4-5.4 km/sec) are predicted upon driving the gun harder (that is, upon using, higher powder loads and/or lower hydrogen fill pressures) when hydrogen loading is neglected; much smaller muzzle velocity gains (1.1-2.2 km/sec) are predicted when hydrogen loading is taken into account. These smaller predicted velocity gains agree well with those achieved in practice. CFD snapshots of the hydrogen mass fraction, density and pressure of the in-bore medium are presented for a very erosive shot.

  4. SCALES: SEVIRI and GERB CaL/VaL area for large-scale field experiments

    NASA Astrophysics Data System (ADS)

    Lopez-Baeza, Ernesto; Belda, Fernando; Bodas, Alejandro; Crommelynck, Dominique; Dewitte, Steven; Domenech, Carlos; Gimeno, Jaume F.; Harries, John E.; Jorge Sanchez, Joan; Pineda, Nicolau; Pino, David; Rius, Antonio; Saleh, Kauzar; Tarruella, Ramon; Velazquez, Almudena

    2004-02-01

    The main objective of the SCALES Project is to exploit the unique opportunity offered by the recent launch of the first European METEOSAT Second Generation geostationary satellite (MSG-1) to generate and validate new radiation budget and cloud products provided by the GERB (Geostationary Earth Radiation Budget) instrument. SCALES" specific objectives are: (i) definition and characterization of a large reasonably homogeneous area compatible to GERB pixel size (around 50 x 50 km2), (ii) validation of GERB TOA radiances and fluxes derived by means of angular distribution models, (iii) development of algorithms to estimate surface net radiation from GERB TOA measurements, and (iv) development of accurate methodologies to measure radiation flux divergence and analyze its influence on the thermal regime and dynamics of the atmosphere, also using GERB data. SCALES is highly innovative: it focuses on a new and unique space instrument and develops a new specific validation methodology for low resolution sensors that is based on the use of a robust reference meteorological station (Valencia Anchor Station) around which 3D high resolution meteorological fields are obtained from the MM5 Meteorological Model. During the 1st GERB Ground Validation Campaign (18th-24th June, 2003), CERES instruments on Aqua and Terra provided additional radiance measurements to support validation efforts. CERES instruments operated in the PAPS mode (Programmable Azimuth Plane Scanning) focusing the station. Ground measurements were taken by lidar, sun photometer, GPS precipitable water content, radiosounding ascents, Anchor Station operational meteorological measurements at 2m and 15m., 4 radiation components at 2m, and mobile stations to characterize a large area. In addition, measurements during LANDSAT overpasses on June 14th and 30th were also performed. These activities were carried out within the GIST (GERB International Science Team) framework, during GERB Commissioning Period.

  5. The one-loop matter bispectrum in the Effective Field Theory of Large Scale Structures

    DOE PAGES

    Angulo, Raul E.; Foreman, Simon; Schmittfull, Marcel; ...

    2015-10-14

    With this study, given the importance of future large scale structure surveys for delivering new cosmological information, it is crucial to reliably predict their observables. The Effective Field Theory of Large Scale Structures (EFTofLSS) provides a manifestly convergent perturbative scheme to compute the clustering of dark matter in the weakly nonlinear regime in an expansion in k/kNL, where k is the wavenumber of interest and kNL is the wavenumber associated to the nonlinear scale. It has been recently shown that the EFTofLSS matches to 1% level the dark matter power spectrum at redshift zero up to k ≃ 0.3 hmore » Mpc–1 and k ≃ 0.6 h Mpc–1 at one and two loops respectively, using only one counterterm that is fit to data. Similar results have been obtained for the momentum power spectrum at one loop. This is a remarkable improvement with respect to former analytical techniques. Here we study the prediction for the equal-time dark matter bispectrum at one loop. We find that at this order it is sufficient to consider the same counterterm that was measured in the power spectrum. Without any remaining free parameter, and in a cosmology for which kNL is smaller than in the previously considered cases (σ8=0.9), we find that the prediction from the EFTofLSS agrees very well with N-body simulations up to k ≃ 0.25 h Mpc–1, given the accuracy of the measurements, which is of order a few percent at the highest k's of interest. While the fit is very good on average up to k ≃ 0.25 h Mpc–1, the fit performs slightly worse on equilateral configurations, in agreement with expectations that for a given maximum k, equilateral triangles are the most nonlinear.« less

  6. Thermodynamically consistent phase field approach to dislocation evolution at small and large strains

    NASA Astrophysics Data System (ADS)

    Levitas, Valery I.; Javanbakht, Mahdi

    2015-09-01

    A thermodynamically consistent, large strain phase field approach to dislocation nucleation and evolution at the nanoscale is developed. Each dislocation is defined by an order parameter, which determines the magnitude of the Burgers vector for the given slip planes and directions. The kinematics is based on the multiplicative decomposition of the deformation gradient into elastic and plastic contributions. The relationship between the rates of the plastic deformation gradient and the order parameters is consistent with phenomenological crystal plasticity. Thermodynamic and stability conditions for homogeneous states are formulated and satisfied by the proper choice of the Helmholtz free energy and the order parameter dependence on the Burgers vector. They allow us to reproduce desired lattice instability conditions and a stress-order parameter curve, as well as to obtain a stress-independent equilibrium Burgers vector and to avoid artificial dissipation during elastic deformation. The Ginzburg-Landau equations are obtained as the linear kinetic relations between the rate of change of the order parameters and the conjugate thermodynamic driving forces. A crystalline energy coefficient for dislocations is defined as a periodic step-wise function of the coordinate along the normal to the slip plane, which provides an energy barrier normal to the slip plane and determines the desired, mesh-independent height of the dislocation bands for any slip system orientation. Gradient energy contains an additional term, which excludes the localization of a dislocation within a height smaller than the prescribed height, but it does not produce artificial interface energy. An additional energy term is introduced that penalizes the interaction of different dislocations at the same point. Non-periodic boundary conditions for dislocations are introduced which include the change of the surface energy due to the exit of dislocations from the crystal. Obtained kinematics, thermodynamics

  7. The large-scale magnetic field in the solar wind. [astronomical models of interplanetary magnetics and the solar magnetic field

    NASA Technical Reports Server (NTRS)

    Burlaga, L. F.; Ness, N. F.

    1976-01-01

    A literature review is presented of theoretical models of the interaction of the solar wind and interplanetary magnetic fields. Observations of interplanetary magnetic fields by the IMP and OSO spacecraft are discussed. The causes for cosmic ray variations (Forbush decreases) by the solar wind are examined. The model of Parker is emphasized. This model shows the three dimensional magnetic field lines of the solar wind to have the form of spirals wrapped on cones. It is concluded that an out-of-the-ecliptic solar probe mission would allow the testing and verification of the various theoretical models examined. Diagrams of the various models are shown.

  8. Phase field approach with anisotropic interface energy and interface stresses: Large strain formulation

    NASA Astrophysics Data System (ADS)

    Levitas, Valery I.; Warren, James A.

    2016-06-01

    A thermodynamically consistent, large-strain, multi-phase field approach (with consequent interface stresses) is generalized for the case with anisotropic interface (gradient) energy (e.g. an energy density that depends both on the magnitude and direction of the gradients in the phase fields). Such a generalization, if done in the "usual" manner, yields a theory that can be shown to be manifestly unphysical. These theories consider the gradient energy as anisotropic in the deformed configuration, and, due to this supposition, several fundamental contradictions arise. First, the Cauchy stress tensor is non-symmetric and, consequently, violates the moment of momentum principle, in essence the Herring (thermodynamic) torque is imparting an unphysical angular momentum to the system. In addition, this non-symmetric stress implies a violation of the principle of material objectivity. These problems in the formulation can be resolved by insisting that the gradient energy is an isotropic function of the gradient of the order parameters in the deformed configuration, but depends on the direction of the gradient of the order parameters (is anisotropic) in the undeformed configuration. We find that for a propagating nonequilibrium interface, the structural part of the interfacial Cauchy stress is symmetric and reduces to a biaxial tension with the magnitude equal to the temperature- and orientation-dependent interface energy. Ginzburg-Landau equations for the evolution of the order parameters and temperature evolution equation, as well as the boundary conditions for the order parameters are derived. Small strain simplifications are presented. Remarkably, this anisotropy yields a first order correction in the Ginzburg-Landau equation for small strains, which has been neglected in prior works. The next strain-related term is third order. For concreteness, specific orientation dependencies of the gradient energy coefficients are examined, using published molecular dynamics

  9. Phase field approach to martensitic phase transformations with large strains and interface stresses

    NASA Astrophysics Data System (ADS)

    Levitas, Valery I.

    2014-10-01

    Thermodynamically consistent phase field theory for multivariant martensitic transformations, which includes large strains and interface stresses, is developed. Theory is formulated in a way that some geometrically nonlinear terms do not disappear in the geometrically linear limit, which in particular allowed us to introduce the expression for the interface stresses consistent with the sharp interface approach. Namely, for the propagating nonequilibrium interface, a structural part of the interface Cauchy stresses reduces to a biaxial tension with the magnitude equal to the temperature-dependent interface energy. Additional elastic and viscous contributions to the interface stresses do not require separate constitutive equations and are determined by solution of the coupled system of phase field and mechanics equations. Ginzburg-Landau equations are derived for the evolution of the order parameters and temperature evolution equation. Boundary conditions for the order parameters include variation of the surface energy during phase transformation. Because elastic energy is defined per unit volume of unloaded (intermediate) configuration, additional contributions to the Ginzburg-Landau equations and the expression for entropy appear, which are important even for small strains. A complete system of equations for fifth- and sixth-degree polynomials in terms of the order parameters is presented in the reference and actual configurations. An analytical solution for the propagating interface and critical martensitic nucleus which includes distribution of components of interface stresses has been found for the sixth-degree polynomial. This required resolving a fundamental problem in the interface and surface science: how to define the Gibbsian dividing surface, i.e., the sharp interface equivalent to the finite-width interface. An unexpected, simple solution was found utilizing the principle of static equivalence. In fact, even two equations for determination of the

  10. Inviscid evolution of large amplitude filaments in a uniform gravity field

    SciTech Connect

    Angus, J. R.; Krasheninnikov, S. I.

    2014-11-15

    The inviscid evolution of localized density stratifications under the influence of a uniform gravity field in a homogeneous, ambient background is studied. The fluid is assumed to be incompressible, and the stratification, or filament, is assumed to be initially isotropic and at rest. It is shown that the center of mass energy can be related to the center of mass position in a form analogous to that of a solid object in a gravity field g by introducing an effective gravity field g{sub eff}, which is less than g due to energy that goes into the background and into non-center of mass motion of the filament. During the early stages of the evolution, g{sub eff} is constant in time and can be determined from the solution of a 1D differential equation that depends on the initial, radially varying density profile of the filament. For small amplitude filaments such that ρ{sub 0} ≪ 1, where ρ{sub 0} is the relative amplitude of the filament to the background, the early stage g{sub eff} scales linearly with ρ{sub 0}, but as ρ{sub 0}→∞, g{sub eff}→g and is thus independent of ρ{sub 0}. Fully nonlinear simulations are performed for the evolution of Gaussian filaments, and it is found that the time t{sub max}, which is defined as the time for the center of mass velocity to reach its maximum value U{sub max}, occurs very soon after the constant acceleration phase and so U{sub max}≈g{sub eff}(t=0)t{sub max}. The simulation results show that U{sub max}∼1/t{sub max}∼√(ρ{sub 0}) for ρ{sub 0} ≪ 1, in agreement with theory and results from previous authors, but that U{sub max} and t{sub max} both scale approximately with √(ρ{sub 0}) for ρ{sub 0} ≫ 1. The fact that U{sub max} and t{sub max} have the same scaling with ρ{sub 0} for large amplitude filaments is in agreement with the theory presented in this paper.

  11. Fiber-optic annular detector array for large depth of field photoacoustic macroscopy.

    PubMed

    Bauer-Marschallinger, Johannes; Höllinger, Astrid; Jakoby, Bernhard; Burgholzer, Peter; Berer, Thomas

    2017-03-01

    We report on a novel imaging system for large depth of field photoacoustic scanning macroscopy. Instead of commonly used piezoelectric transducers, fiber-optic based ultrasound detection is applied. The optical fibers are shaped into rings and mainly receive ultrasonic signals stemming from the ring symmetry axes. Four concentric fiber-optic rings with varying diameters are used in order to increase the image quality. Imaging artifacts, originating from the off-axis sensitivity of the rings, are reduced by coherence weighting. We discuss the working principle of the system and present experimental results on tissue mimicking phantoms. The lateral resolution is estimated to be below 200 μm at a depth of 1.5 cm and below 230 μm at a depth of 4.5 cm. The minimum detectable pressure is in the order of 3 Pa. The introduced method has the potential to provide larger imaging depths than acoustic resolution photoacoustic microscopy and an imaging resolution similar to that of photoacoustic computed tomography.

  12. Disordered nanocrystalline superconducting PbMo6S8 with a very large upper critical field.

    PubMed

    Niu, H J; Hampshire, D P

    2003-07-11

    Large increases in the upper critical field B(C2)(0) are reported in bulk superconductors that demonstrate another novel property for nanocrystalline materials. Disordered nanocrystalline PbMo6S8 superconductors were fabricated by mechanical milling and hot isostatic pressing. Conventional PbMo6S8 has B(C2)(0) approximately 50 T. The nanocrystalline materials have higher resistivity (rho(N)) and B(C2)(0) approximately 100 T. The disorder produced in these nanocrystalline materials is significantly different from that produced by doping because it increases rho(N) and, hence, B(C2)(0) without significantly reducing the electronic density of states or superconducting transition temperature (T(C)). Furthermore, the disorder reduces the electron mean-free path to approximately 1 nm which is more than an order of magnitude smaller than the grain size and necessary to achieve the unprecedented increase in B(C2)(0).

  13. Large trigonal-field effect on spin-orbit coupled states in a pyrochlore iridate

    NASA Astrophysics Data System (ADS)

    Uematsu, Daisuke; Sagayama, Hajime; Arima, Taka-hisa; Ishikawa, Jun J.; Nakatsuji, Satoru; Takagi, Hidenori; Yoshida, Masahiro; Mizuki, Jun'ichiro; Ishii, Kenji

    2015-09-01

    The half-filled topmost valence band of Ir4 + in several iridates such as Sr2IrO4 ,IrO2, and CaIrO3 has been proposed to originate mainly from the spin-orbit coupled Jeff=1 /2 states. In pyrochlore iridates R2Ir2O7 (R : rare earth), some exotic electronic states are theoretically proposed by assuming Jeff=1 /2 states. However, the octahedral coordination around Ir is trigonally distorted, which may affect the energy level scheme of Ir 5 d states. Here, we report spectra of resonant elastic and inelastic x-ray scattering in Eu2Ir2O7 at the Ir L edges. A large suppression of the magnetic scattering signal at the Ir LII edge supports the Jeff=1 /2 picture rather than the S =1 /2 one. The inelastic scattering spectrum indicates that the magnitude of the trigonal field on the Ir4 + states is evaluated to be comparable to the spin-orbit interaction. The energy diagram of the 5 d state is proposed based on the simple cluster model.

  14. Portable oral cancer detection using a miniature confocal imaging probe with a large field of view

    NASA Astrophysics Data System (ADS)

    Wang, Youmin; Raj, Milan; McGuff, H. Stan; Bhave, Gauri; Yang, Bin; Shen, Ting; Zhang, Xiaojing

    2012-06-01

    We demonstrate a MEMS micromirror enabled handheld confocal imaging probe for portable oral cancer detection, where a comparatively large field of view (FOV) was generated through the programmable Lissajous scanning pattern of the MEMS micromirror. Miniaturized handheld MEMS confocal imaging probe was developed, and further compared with the desktop confocal prototype under clinical setting. For the handheld confocal imaging system, optical design simulations using CODE VR® shows the lateral and axial resolution to be 0.98 µm and 4.2 µm, where experimental values were determined to be 3 µm and 5.8 µm, respectively, with a FOV of 280 µm×300 µm. Fast Lissajous imaging speed up to 2 fps was realized with improved Labview and Java based real-time imaging software. Properties such as 3D imaging through autofocusing and mosaic imaging for extended lateral view (6 mm × 8 mm) were examined for carcinoma real-time pathology. Neoplastic lesion tissues of giant cell fibroma and peripheral ossifying fibroma, the fibroma inside the paraffin box and ex vivo gross tissues were imaged by the bench-top and handheld imaging modalities, and further compared with commercial microscope imaging results. The MEMS scanner-based handheld confocal imaging probe shows great promise as a potential clinical tool for oral cancer diagnosis and treatment.

  15. Wide-band acousto-optic deflectors for large field of view two-photon microscope.

    PubMed

    Jiang, Runhua; Zhou, Zhenqiao; Lv, Xiaohua; Zeng, Shaoqun

    2012-04-01

    Acousto-optic deflector (AOD) is an attractive scanner for two-photon microscopy because it can provide fast and versatile laser scanning and does not involve any mechanical movements. However, due to the small scan range of available AOD, the field of view (FOV) of the AOD-based microscope is typically smaller than that of the conventional galvanometer-based microscope. Here, we developed a novel wide-band AOD to enlarge the scan angle. Considering the maximum acceptable acoustic attenuation in the acousto-optic crystal, relatively lower operating frequencies and moderate aperture were adopted. The custom AOD was able to provide 60 MHz 3-dB bandwidth and 80% peak diffraction efficiency at 840 nm wavelength. Based on a pair of such AOD, a large FOV two-photon microscope was built with a FOV up to 418.5 μm (40× objective). The spatiotemporal dispersion was compensated simultaneously with a single custom-made prism. By means of dynamic power modulation, the variation of laser intensity within the FOV was reduced below 5%. The lateral and axial resolution of the system were 0.58-2.12 μm and 2.17-3.07 μm, respectively. Pollen grain images acquired by this system were presented to demonstrate the imaging capability at different positions across the entire FOV.

  16. Large dose hyperpolarized water with dissolution-DNP at high magnetic field

    NASA Astrophysics Data System (ADS)

    Lipsø, Kasper Wigh; Bowen, Sean; Rybalko, Oleksandr; Ardenkjær-Larsen, Jan Henrik

    2017-01-01

    We demonstrate a method for the preparation of hyperpolarized water by dissolution Dynamic Nuclear Polarization at high magnetic field. Protons were polarized at 6.7 T and 1.1 K to >70% with frequency modulated microwave irradiation at 188G Hz. 97.2 ± 0.7% of the radical was extracted from the sample in the dissolution in a two-phase system. 16 ± 1 mL of 5.0 M 1H in D2O with a polarization of 13.0 ± 0.9% in the liquid state was obtained, corresponding to an enhancement factor of 4000 ± 300 compared to the thermal equilibrium at 9.4 T and 293 K. A longitudinal relaxation time constant of 16 ± 1 s was measured. The sample was polarized and dissolved in a fluid path compatible with clinical polarizers. The volume of hyperpolarized water produced by this method enables angiography and perfusion measurements in large animals, as well as NMR experiments for studies of e.g. proton exchange and polarization transfer to other nuclei.

  17. Tomographic control for wide field AO systems on extremely large telescopes

    NASA Astrophysics Data System (ADS)

    Petit, C.; Conan, J.-M.; Fusco, T.; Neichel, B.

    2010-07-01

    We investigate in this article tomographic control using both Laser and Natural Guide Stars (LGS and NGS) in the particular framework of the European Extremely Large Telescope (E-ELT) Wide Field Adaptive Optics (WFAO) modules design. A similar global control strategy has been indeed derived for both the Laser Tomographic Adaptive Optics (LTAO) and Multi-Conjugate Adaptive Optics (MCAO) modules of the E-ELT, due to similar constraints. This control strategy leads in both cases to a split control of low order modes measured thanks to NGS and high order modes measured thanks to LGS. We investigate here this split tomographic control, compared to an optimal coupled solution. To support our analysis, a dedicated simulation code has been developed. Indeed, due to the huge complexity of the EELT, fast simulation tools must be considered to explore quickly the tomographic issues. We describe our control strategy which has lead to considering split tomographic control. First results on Tomography for E-ELT WFAO systems are then presented and discussed.

  18. Large-Field CO(J = 1→0) Observations of the Starburst Galaxy M 82

    NASA Astrophysics Data System (ADS)

    Salak, Dragan; Nakai, Naomasa; Miyamoto, Yusuke; Yamauchi, Aya; Tsuru, Takeshi G.

    2013-06-01

    We present large-field (15.7 × 16.9 arcmin2) CO(J = 1→0) observations of the starburst galaxy M 82, at an angular resolution of 22" with the NRO 45-m telescope. The CO emission was detected in the galactic disk, outflow (driven by the galactic wind) up to ˜2 kpc above the galactic plane in the halo, and in tidal streams. The kinematics of the outflow (including CO line splitting) suggests that it has the shape of a cylinder that is diverging outwards. The mass and kinetic energy of the molecular gas outflow are estimated to be (0.26-1.0) × 109 M⊙ and (1-4) × 1056 erg. A clump of CO gas was discovered 3.5 kpc above the galactic plane; it coincides with a dark lane previously found in X-ray observations, and a peak in H I emission. A comparison with H I, hot molecular hydrogen and dust suggests that the molecular gas shows signatures of warm and cool components in the outflow and tidal streams, respectively.

  19. Large field distributed aperture laser semiactive angle measurement system design with imaging fiber bundles.

    PubMed

    Xu, Chunyun; Cheng, Haobo; Feng, Yunpeng; Jing, Xiaoli

    2016-09-01

    A type of laser semiactive angle measurement system is designed for target detecting and tracking. Only one detector is used to detect target location from four distributed aperture optical systems through a 4×1 imaging fiber bundle. A telecentric optical system in image space is designed to increase the efficiency of imaging fiber bundles. According to the working principle of a four-quadrant (4Q) detector, fiber diamond alignment is adopted between an optical system and a 4Q detector. The structure of the laser semiactive angle measurement system is, we believe, novel. Tolerance analysis is carried out to determine tolerance limits of manufacture and installation errors of the optical system. The performance of the proposed method is identified by computer simulations and experiments. It is demonstrated that the linear region of the system is ±12°, with measurement error of better than 0.2°. In general, this new system can be used with large field of view and high accuracy, providing an efficient, stable, and fast method for angle measurement in practical situations.

  20. Release model for in situ vitrification large-field test off-gas treatment system

    SciTech Connect

    Pafford, D.J.; Tung, V.X.

    1992-03-01

    A conceptual model for the vapor and aerosol transport and deposition in the in situ vitrification large-field test off-gas system (OGS) has been developed. This model can be used to predict the emissions from the OGS under normal and off-normal conditions. Results generated by the model can be used to evaluate design and/or procedural modifications, define tests, and predict results. The OGS vapor and aerosol transport and deposition is modeled using the PULSE/MOD-ISV/VER 1.0.0 developmental computer code. Input data requirements for this code include the specific geometries of the OGS components; the composition, rate, and temperature of the vapors and aerosols entering the OGS; and the OGS component surface temperatures or heat fluxes. Currently, not all of these model inputs are available. Therefore, conceptual input parameters are developed. Using this input data, preliminary calculations with the code have been performed. These calculations include a demonstration that the code predicts convergent results, a comparison of predicted results with performance data for one of the OGS components, and a preliminary sensitivity study of the complete model.

  1. Large Eddy Simulations and an Analysis of the Flow Field of a Radially Lobed Nozzle

    NASA Astrophysics Data System (ADS)

    Amini, Noushin; Sekaran, Aarthi

    2015-11-01

    Lobed nozzles have been a subject of regained interest over the past couple of decades owing to their established mixing capabilities. Despite experimental (Hu et al., 1999 and Hu et al., 2008) and limited numerical studies (Boulenouar et al. 2011 and Cooper et al., 2005), the exact nature of the jet ensuing from this nozzle is yet to be completely understood. The present numerical study is intended to complement prior experimental investigation, involving the analysis of the flow field downstream of a six lobed nozzle (Amini et al., 2012). Preliminary results (presented at DFD 2014, Amin and Sekaran), which involved three dimensional simulations of the full domain via URANS and Large Eddy Simulations (LES) were used to assess the domain extents and simulation technique. Based on these results it was seen that LES were able to capture the region of interest satisfactorily and a qualitative corroboration with previous studies was obtained. The study is thus extended to analyzing the flow originating from within the nozzle, following it downstream in order to confirm the vortical interaction mechanisms inside the lobed nozzle.

  2. Huddling facilitates expression of daily torpor in the large Japanese field mouse Apodemus speciosus.

    PubMed

    Eto, Takeshi; Sakamoto, Shinsuke H; Okubo, Yoshinobu; Koshimoto, Chihiro; Kashimura, Atsushi; Morita, Tetsuo

    2014-06-22

    Small endotherms employ multiple adaptations to maintain energy balance in winter, including spontaneous daily torpor and simultaneous huddling. The relationships between these adaptations have been discussed in several previous studies, but it has not been well-established if huddling actually affects the expression of torpor in small endotherms. We examine whether and how huddling affects the expression of torpor in the large Japanese field mouse Apodemus speciosus, which is known to become torpid under artificial winter conditions. The mice were found to adjust expression of torpor in response to the number of cage mates. Torpor frequency and minimum torpid body temperature were both significantly elevated when the number of cage mates was increased, but there was no significant change in torpor bout length. Rewarming rate on arousal was lower when the number of cage mates was increased, suggesting reduction in endogenous rewarming due to exogenous passive rewarming. Food consumption per mouse decreased significantly with increasing number of cage mates. Thus, our study demonstrates that social thermoregulatory behaviors such as huddling can facilitate expression of spontaneous daily torpor in small rodents. These findings suggest that energy constraints, such as ambient temperature and food availability may not be the only modulating factors on the expression of daily torpor.

  3. Optical characterization of a miniaturized large field of view motion sensor

    NASA Astrophysics Data System (ADS)

    Moens, Els; Ottevaere, Heidi; Meuret, Youri; Thienpont, Hugo

    2012-06-01

    In this paper we discuss the geometrical and optical characterization of a miniaturized very wide field-of-view (FOV) motion sensor inspired by the working principle of insect facet eyes. The goal of the sensor is to detect movement in the environment and to specify where in the surroundings these changes took place. Based on the measurements of the sensor, certain actions can be taken such as sounding an alarm in security applications or turning on the light in domotic applications. The advantage of miniaturizing these sensors is that they are low-cost, compact and more esthetical compared to current motion detectors. The sensor was designed to have a very large FOV of 125° and an angular resolution of 1° or better. The micro-optics is built up of two stacked polymer plates consisting each out of a five by five lens array. In between there is a plate of absorbing material with a five by five array of baffles to create 25 optically isolated channels that each image part of the total FOV of 125° onto the detector. To geometrically characterize the lens arrays and verify the designed specifications, we made use of a coordinate measuring machine. The optical performance of the designed micro-optical system was analyzed by sending white light beams with different angles of incidence with respect to the sample through the sensor, comparing the position of the light spots visible on the detector and determining optical quality parameters such as MTF and distortion.

  4. Principal shapes and squeezed limits in the effective field theory of large scale structure

    NASA Astrophysics Data System (ADS)

    Bertolini, Daniele; Solon, Mikhail P.

    2016-11-01

    We apply an orthogonalization procedure on the effective field theory of large scale structure (EFT of LSS) shapes, relevant for the angle-averaged bispectrum and non-Gaussian covariance of the matter power spectrum at one loop. Assuming natural-sized EFT parameters, this identifies a linear combination of EFT shapes—referred to as the principal shape—that gives the dominant contribution for the whole kinematic plane, with subdominant combinations suppressed by a few orders of magnitude. For the covariance, our orthogonal transformation is in excellent agreement with a principal component analysis applied to available data. Additionally we find that, for both observables, the coefficients of the principal shapes are well approximated by the EFT coefficients appearing in the squeezed limit, and are thus measurable from power spectrum response functions. Employing data from N-body simulations for the growth-only response, we measure the single EFT coefficient describing the angle-averaged bispectrum with 𝒪(10%) precision. These methods of shape orthogonalization and measurement of coefficients from response functions are valuable tools for developing the EFT of LSS framework, and can be applied to more general observables.

  5. Planck limits on non-canonical generalizations of large-field inflation models

    NASA Astrophysics Data System (ADS)

    Stein, Nina K.; Kinney, William H.

    2017-04-01

    In this paper, we consider two case examples of Dirac-Born-Infeld (DBI) generalizations of canonical large-field inflation models, characterized by a reduced sound speed, cS < 1. The reduced speed of sound lowers the tensor-scalar ratio, improving the fit of the models to the data, but increases the equilateral-mode non-Gaussianity, fequil.NL, which the latest results from the Planck satellite constrain by a new upper bound. We examine constraints on these models in light of the most recent Planck and BICEP/Keck results, and find that they have a greatly decreased window of viability. The upper bound on fequil.NL corresponds to a lower bound on the sound speed and a corresponding lower bound on the tensor-scalar ratio of r ~ 0.01, so that near-future Cosmic Microwave Background observations may be capable of ruling out entire classes of DBI inflation models. The result is, however, not universal: infrared-type DBI inflation models, where the speed of sound increases with time, are not subject to the bound.

  6. Powering up with indirect reciprocity in a large-scale field experiment.

    PubMed

    Yoeli, Erez; Hoffman, Moshe; Rand, David G; Nowak, Martin A

    2013-06-18

    A defining aspect of human cooperation is the use of sophisticated indirect reciprocity. We observe others, talk about others, and act accordingly. We help those who help others, and we cooperate expecting that others will cooperate in return. Indirect reciprocity is based on reputation, which spreads by communication. A crucial aspect of indirect reciprocity is observability: reputation effects can support cooperation as long as peoples' actions can be observed by others. In evolutionary models of indirect reciprocity, natural selection favors cooperation when observability is sufficiently high. Complimenting this theoretical work are experiments where observability promotes cooperation among small groups playing games in the laboratory. Until now, however, there has been little evidence of observability's power to promote large-scale cooperation in real world settings. Here we provide such evidence using a field study involving 2413 subjects. We collaborated with a utility company to study participation in a program designed to prevent blackouts. We show that observability triples participation in this public goods game. The effect is over four times larger than offering a $25 monetary incentive, the company's previous policy. Furthermore, as predicted by indirect reciprocity, we provide evidence that reputational concerns are driving our observability effect. In sum, we show how indirect reciprocity can be harnessed to increase cooperation in a relevant, real-world public goods game.

  7. Enhanced Energy Density in Permanent Magnets using Controlled High Magnetic Field during Processing

    SciTech Connect

    Rios, Orlando; Carter, Bill; Constantinides, Steve

    2016-05-05

    This ORNL Manufacturing Demonstraction Facility (MDF) technical collaboration focused on the use of high magnetic field processing (>2Tesla) using energy efficient large bore superconducting magnet technology and high frequency electromagnetics to improve magnet performance and reduce the energy budget associated with Alnico thermal processing. Alnico, alloys containing Al, Ni, Co and Fe, represent a class of functional nanostructured alloys, and show the greatest potential for supplementing or replacing commercial Nd-based rare-earth alloy magnets.

  8. Insights From Field Geology Into the Styles and Timings of Large Silicic Explosive `Supereruptions'

    NASA Astrophysics Data System (ADS)

    Wilson, C. J.

    2006-12-01

    The evocative terms `supereruption' (and `supervolcano'), whilst eminently saleable to the media, conceal the fact that, apart from knowing that such large eruptions (>300 km3, magma) actually have occurred, we understand very little about the dynamics of such events. Field studies of 3 supereruption deposits suggest that we are missing information on the timing and eruptive styles that is essential in assessing the dynamics and impacts of past and future large eruptions. The 26.5 ka Oruanui eruption in New Zealand (ca. 530 km3, magma) shows evidence in the form of erosion intervals and/or reworked horizons for spasmodic activity, including a hiatus of weeks plus other shorter breaks, that interrupted 10 phases of activity. Following the plinian fall unit of phase 1, there was a time break long enough for local reworking (and possibly emplacement of a small dome), thus of the order of weeks in duration. Other breaks, during which minor wind- or water-reworking took place are observed between phases 4 and 5, and 9 and 10, and were of the order of days. Two other horizons saw the complete settling out of 10-20 micron-sized ash particles before commencement of the next phase of the eruption, and thus may represent breaks of hours. The whole eruption was a series of large-scale outbreaks of generally increasing vigor, daisy-chained to form a single geological event, but one which would represent recurrent hazards, and uncertainties in eruptive activity if repeated today. The 0.76 Ma Bishop Tuff eruption (ca. 600 km3, magma), on the other hand, displays evidence only for one short time break, represented by settling out of fine ash at the top of a plinian pumice fall unit. Most of the eruption volume may have been emplaced over only about 6 days. Such an eruption, although catastrophic when placed in today's societal context, at least was over relatively rapidly. The immense 2.06 Ma Huckleberry Ridge Tuff (HRT) eruption (ca. 2500 km3, magma) shows evidence for prolonged

  9. Stability of the unswitched ferroelectric polarization state in ultrathin epitaxial Pb(Zr,Ti)O3 in large electric fields

    SciTech Connect

    Grigoriev, Alexei; Sichel, Rebecca; Jo, Ji Young; Choudhury, Samrat; Chen, L. Q.; Lee, Ho Nyung; Landahl, Eric C.; Adams, Bernhard; Dufresne, Eric M.; Evans, Paul G.

    2009-01-01

    A series of 50 ns-duration electric field pulses switches the polarization of a 35 nm-thick ferroelectric Pb(Zr,Ti)O3 film only at electric fields greater than 1.5 MV/cm, a factor of three higher than the low-frequency coercive field. There is no switching in response to a large number of pulses with lower fields, even when the total duration reaches several milliseconds. During longer microsecond-duration electric fields, however, switching progresses monotonically in both x-ray microdiffraction images and in electrical measurements. The difference between long and short electric field durations arises from domain nucleation and charge transport. A phase field model shows that the shrinking of the switched domain in the interval between pulses is a less important effect.

  10. Large-scale, near-Earth, magnetic fields from external sources and the corresponding induced internal field

    NASA Technical Reports Server (NTRS)

    Langel, R. A.; Estes, R. H.

    1983-01-01

    Data from MAGSAT analyzed as a function of the Dst index to determine the first degree/order spherical harmonic description of the near-Earth external field and its corresponding induced field. The analysis was done separately for data from dawn and dusk. The MAGSAT data was compared with POGO data. A local time variation of the external field persists even during very quiet magnetic conditions; both a diurnal and 8-hour period are present. A crude estimate of Sq current in the 45 deg geomagnetic latitude range is obtained for 1966 to 1970. The current strength, located in the ionosphere and induced in the Earth, is typical of earlier determinations from surface data, although its maximum is displaced in local time from previous results.

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

    NASA Astrophysics Data System (ADS)

    Javanbakht, Mahdi; Levitas, Valery I.

    2016-12-01

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

  12. The one-loop matter bispectrum in the Effective Field Theory of Large Scale Structures

    SciTech Connect

    Angulo, Raul E.; Foreman, Simon; Senatore, Leonardo; Schmittfull, Marcel E-mail: sfore@stanford.edu E-mail: senatore@stanford.edu

    2015-10-01

    Given the importance of future large scale structure surveys for delivering new cosmological information, it is crucial to reliably predict their observables. The Effective Field Theory of Large Scale Structures (EFTofLSS) provides a manifestly convergent perturbative scheme to compute the clustering of dark matter in the weakly nonlinear regime in an expansion in k/k{sub NL}, where k is the wavenumber of interest and k{sub NL} is the wavenumber associated to the nonlinear scale. It has been recently shown that the EFTofLSS matches to 1% level the dark matter power spectrum at redshift zero up to k≅ 0.3 h Mpc{sup −1} and k≅ 0.6 h Mpc{sup −1} at one and two loops respectively, using only one counterterm that is fit to data. Similar results have been obtained for the momentum power spectrum at one loop. This is a remarkable improvement with respect to former analytical techniques. Here we study the prediction for the equal-time dark matter bispectrum at one loop. We find that at this order it is sufficient to consider the same counterterm that was measured in the power spectrum. Without any remaining free parameter, and in a cosmology for which k{sub NL} is smaller than in the previously considered cases (σ{sub 8}=0.9), we find that the prediction from the EFTofLSS agrees very well with N-body simulations up to k≅ 0.25 h Mpc{sup −1}, given the accuracy of the measurements, which is of order a few percent at the highest k's of interest. While the fit is very good on average up to k≅ 0.25 h Mpc{sup −1}, the fit performs slightly worse on equilateral configurations, in agreement with expectations that for a given maximum k, equilateral triangles are the most nonlinear.

  13. Large-field-of-view wide-spectrum artificial reflecting superposition compound eyes

    NASA Astrophysics Data System (ADS)

    Huang, Chi-Chieh

    The study of the imaging principles of natural compound eyes has become an active area of research and has fueled the advancement of modern optics with many attractive design features beyond those available with conventional technologies. Most prominent among all compound eyes is the reflecting superposition compound eyes (RSCEs) found in some decapods. They are extraordinary imaging systems with numerous optical features such as minimum chromatic aberration, wide-angle field of view (FOV), high sensitivity to light and superb acuity to motion. Inspired by their remarkable visual system, we were able to implement the unique lens-free, reflection-based imaging mechanisms into a miniaturized, large-FOV optical imaging device operating at the wide visible spectrum to minimize chromatic aberration without any additional post-image processing. First, two micro-transfer printing methods, a multiple and a shear-assisted transfer printing technique, were studied and discussed to realize life-sized artificial RSCEs. The processes exploited the differential adhesive tendencies of the microstructures formed between a donor and a transfer substrate to accomplish an efficient release and transfer process. These techniques enabled conformal wrapping of three-dimensional (3-D) microstructures, initially fabricated in two-dimensional (2-D) layouts with standard fabrication technology onto a wide range of surfaces with complex and curvilinear shapes. Final part of this dissertation was focused on implementing the key operational features of the natural RSCEs into large-FOV, wide-spectrum artificial RSCEs as an optical imaging device suitable for the wide visible spectrum. Our devices can form real, clear images based on reflection rather than refraction, hence avoiding chromatic aberration due to dispersion by the optical materials. Compared to the performance of conventional refractive lenses of comparable size, our devices demonstrated minimum chromatic aberration, exceptional

  14. The one-loop matter bispectrum in the Effective Field Theory of Large Scale Structures

    SciTech Connect

    Angulo, Raul E.; Foreman, Simon; Schmittfull, Marcel; Senatore, Leonardo

    2015-10-14

    With this study, given the importance of future large scale structure surveys for delivering new cosmological information, it is crucial to reliably predict their observables. The Effective Field Theory of Large Scale Structures (EFTofLSS) provides a manifestly convergent perturbative scheme to compute the clustering of dark matter in the weakly nonlinear regime in an expansion in k/kNL, where k is the wavenumber of interest and kNL is the wavenumber associated to the nonlinear scale. It has been recently shown that the EFTofLSS matches to 1% level the dark matter power spectrum at redshift zero up to k ≃ 0.3 h Mpc–1 and k ≃ 0.6 h Mpc–1 at one and two loops respectively, using only one counterterm that is fit to data. Similar results have been obtained for the momentum power spectrum at one loop. This is a remarkable improvement with respect to former analytical techniques. Here we study the prediction for the equal-time dark matter bispectrum at one loop. We find that at this order it is sufficient to consider the same counterterm that was measured in the power spectrum. Without any remaining free parameter, and in a cosmology for which kNL is smaller than in the previously considered cases (σ8=0.9), we find that the prediction from the EFTofLSS agrees very well with N-body simulations up to k ≃ 0.25 h Mpc–1, given the accuracy of the measurements, which is of order a few percent at the highest k's of interest. While the fit is very good on average up to k ≃ 0.25 h Mpc–1, the fit performs slightly worse on equilateral configurations, in agreement with expectations that for a given maximum k, equilateral triangles are the most nonlinear.

  15. Electron acceleration at a coronal shock propagating through a large-scale streamer-like magnetic field

    SciTech Connect

    Kong, Xiangliang; Chen, Yao; Guo, Fan; Feng, Shiwei; Du, Guohui; Li, Gang

    2016-04-05

    With a test-particle simulation, we investigate the effect of large-scale coronal magnetic fields on electron acceleration at an outward-propagating coronal shock with a circular front. The coronal field is approximated by an analytical solution with a streamer-like magnetic field featured by partially open magnetic field and a current sheet at the equator atop the closed region. We show that the large-scale shock-field configuration, especially the relative curvature of the shock and the magnetic field line across which the shock is sweeping, plays an important role in the efficiency of electron acceleration. At low shock altitudes, when the shock curvature is larger than that of magnetic field lines, the electrons are mainly accelerated at the shock flanks; at higher altitudes, when the shock curvature is smaller, the electrons are mainly accelerated at the shock nose around the top of closed field lines. The above process reveals the shift of efficient electron acceleration region along the shock front during its propagation. We also found that in general the electron acceleration at the shock flank is not so efficient as that at the top of closed field since at the top a collapsing magnetic trap can be formed. In addition, we find that the energy spectra of electrons is power-law like, first hardening then softening with the spectral index varying in a range of -3 to -6. In conclusion, physical interpretations of the results and implications on the study of solar radio bursts are discussed.

  16. Impact of magnetic topology on radial electric field profile in the scrape-off layer of the Large Helical Device

    NASA Astrophysics Data System (ADS)

    Suzuki, Y.; Ida, K.; Kamiya, K.; Yoshinuma, M.; Tsuchiya, H.; Kobayashi, M.; Kawamura, G.; Ohdachi, S.; Sakakibara, S.; Watanabe, K. Y.; Hudson, S.; Feng, Y.; Yamada, I.; Yasuhara, R.; Tanaka, K.; Akiyama, T.; Morisaki, T.; The LHD Experiment Group

    2016-09-01

    The radial electric field in the plasma edge is studied in the Large Helical Device (LHD) experiments. When magnetic field lines become stochastic or open at the plasma edge and connected to the vessel, electrons are lost faster than ions along these field lines. Then, a positive electric field appears in the plasma edge. The radial electric field profile can be used to detect the effective plasma boundary. Magnetic topology is an important issue in stellarator and tokamak research because the 3D boundary has the important role of controlling MHD edge stability with respect to ELMs, and plasma detachment. Since the stochastic magnetic field layer can be controlled in the LHD by changing the preset vacuum magnetic axis, this device is a good platform to study the properties of the radial electric field that appear with the different stochastic layer width. Two magnetic configurations with different widths of the stochastic layer as simulated in vacuum are studied for low-β discharges. It has been found that a positive electric field appeared outside of the last closed flux surface. In fact the positions of the positive electric field are found in the boundary between of the stochastic layer and the scrape-off layer. To understand where is the boundary of the stochastic layer and the scrape-off layer, the magnetic field lines are analyzed statistically. The variance of the magnetic field lines in the stochastic layer is increased outwards for both configurations. However, the skewness, which means the asymmetry of the distribution of the magnetic field line, increases for only one configuration. If the skewness is large, the connection length becomes effectively short. Since that is consistent with the experimental observation, the radial electric field can be considered as an index of the magnetic topology.

  17. Duration and extent of large electric fields in a thunderstorm anvil cloud after the last lightning

    NASA Astrophysics Data System (ADS)

    Stolzenburg, Maribeth; Marshall, Thomas C.; Krehbiel, Paul R.

    2010-10-01

    A series of balloon electric field (E) soundings and time-correlated radar scans through the balloon locations are used to examine the evolution of charge and reflectivity inside a dissipating thunderstorm anvil. The soundings cover a 75 min period during and after the final lightning flash in distant convection. The first sounding measured large E magnitudes (maximum 65 kV m-1) and significant charge densities of both polarities (maximum +2.5 nC m-3) within and screening the anvil. Little change in the maximum E values occurred in the 30 min between the first and third soundings, although altitudes and densities of some charge regions decreased with time (maximum +0.6 nC m-3). Screening charge regions were observed in close coincidence with 12 dbZ radar reflectivity contours, and interior positive charge was found in the reflectivity maxima of both anvil decks. The fourth sounding ascended through visible but optically less dense cloud, and no enhanced E values were detected. Overall, the data indicate the interior positive charge region of the main anvil contained about 150 C and covered at least 250 km2 nearly 30 min after the last lightning flash. Potentially hazardous E values of 30-35 kV m-1 were measured at 9.9-10.2 km altitude, a common jet aircraft cruising altitude, more than 20 km away from and 32 min after the final lightning flash. About 50 min after the last flash, the main positive charge region contained an estimated 50 C, and potentially hazardous E values associated with the anvil extended over at least 220 km2.

  18. A large-scale field assessment of carbon stocks in human-modified tropical forests.

    PubMed

    Berenguer, Erika; Ferreira, Joice; Gardner, Toby Alan; Aragão, Luiz Eduardo Oliveira Cruz; De Camargo, Plínio Barbosa; Cerri, Carlos Eduardo; Durigan, Mariana; Cosme De Oliveira Junior, Raimundo; Vieira, Ima Célia Guimarães; Barlow, Jos

    2014-12-01

    Tropical rainforests store enormous amounts of carbon, the protection of which represents a vital component of efforts to mitigate global climate change. Currently, tropical forest conservation, science, policies, and climate mitigation actions focus predominantly on reducing carbon emissions from deforestation alone. However, every year vast areas of the humid tropics are disturbed by selective logging, understory fires, and habitat fragmentation. There is an urgent need to understand the effect of such disturbances on carbon stocks, and how stocks in disturbed forests compare to those found in undisturbed primary forests as well as in regenerating secondary forests. Here, we present the results of the largest field study to date on the impacts of human disturbances on above and belowground carbon stocks in tropical forests. Live vegetation, the largest carbon pool, was extremely sensitive to disturbance: forests that experienced both selective logging and understory fires stored, on average, 40% less aboveground carbon than undisturbed forests and were structurally similar to secondary forests. Edge effects also played an important role in explaining variability in aboveground carbon stocks of disturbed forests. Results indicate a potential rapid recovery of the dead wood and litter carbon pools, while soil stocks (0-30 cm) appeared to be resistant to the effects of logging and fire. Carbon loss and subsequent emissions due to human disturbances remain largely unaccounted for in greenhouse gas inventories, but by comparing our estimates of depleted carbon stocks in disturbed forests with Brazilian government assessments of the total forest area annually disturbed in the Amazon, we show that these emissions could represent up to 40% of the carbon loss from deforestation in the region. We conclude that conservation programs aiming to ensure the long-term permanence of forest carbon stocks, such as REDD+, will remain limited in their success unless they effectively

  19. Packing assembly for use in a plunger bore

    SciTech Connect

    Cameron, D.C.; Cobb, H.V.; Winn, F.M.

    1986-02-25

    A packing assembly is described which is adapted to be installed in a machine, such as a pump, the machine having a housing with a plunger bore and a plunger therin to provide a fluid-tight seal for the machine. The assembly consists of: a packing gland which fastens into one end of the plunger bore; a packing gland spacer positioned adjacent to and in contact with the packing gland; a lubrication gland positioned adjacent to and in contact with the packing gland spacer; a separate stack of packing rings, which includes at least two packing rings, each ring in the stack has a front face defining a concave shape, a rear face defining a convex shape, and a groove, defining a concave shape, in the front face; a female adaptor ring positioned between the lubrication gland and the packing ring stack, the female adaptor ring has a front face with a concave shape, the concave shape defines an angle which substantially conforms to the angle defined by the convex shape of the rear face of the last packing ring in the stack, such that the front face of the female adaptor ring can seat firmly against the rear face of the last packing ring; a male-female adaptor ring positioned between two packing rings in the stack, the male-female adaptor ring has a front face and rear face, the rear face has a convex shape and an integral rib member defining a convex shape, on the rear face, and the front face has a concave shape; the convex shape of the rear face of the male-female adaptor ring defines an angle which substantially conforms to the angle defined by the concave shape of the front face of the last packing ring in the stack and the convex shape of the face of the last packing ring in the stack and the convex shape of the rib member substantially conforms to the concave shape of the groove in the front face of the last packing ring.

  20. Generation of low-frequency electric and magnetic fields during large- scale chemical and nuclear explosions

    SciTech Connect

    Adushkin, V.V.; Dubinya, V.A.; Karaseva, V.A.; Soloviev, S.P.; Surkov, V.V.

    1995-06-01

    We discuss the main parameters of the electric field in the surface layer of the atmosphere and the results of the investigations of the natural electric field variations. Experimental investigations of the electromagnetic field for explosions in air are presented. Electromagnetic signals generated by underground nuclear and chemical explosions are discussed and explosions for 1976--1991 are listed. Long term anomalies of the earth`s electromagnetic field in the vicinity of underground explosions were also investigated. Study of the phenomenon of the irreversible shock magnetization showed that in the zone nearest to the explosion the quasistatic magnetic field decreases in inverse proportion to the distance.

  1. Mixing and sediment resuspension associated with internal bores in a shallow bay

    NASA Astrophysics Data System (ADS)

    Masunaga, Eiji; Homma, Hikaru; Yamazaki, Hidekatsu; Fringer, Oliver B.; Nagai, Takeyoshi; Kitade, Yujiro; Okayasu, Akio

    2015-11-01

    Observations of the run-up of internal bores in a shallow bay were made with a tow-yo instrument and mooring arrays with high spatial and temporal resolution. Shoreward propagating internal bores have been studied with laboratory experiments and numerical models, but few observational studies have shown the detailed structure of the run-up of internal bores induced by internal tides. Our observations showed that internal bores propagate along the slope, accompanied by strong turbulent mixing and strong sediment resuspension in a shallow bay. The isothermal displacement due to the bores reached 20 m vertically in a water depth of 40 m. Turbidity measurements showed suspended particles transported from the sloping bottom and offshore above the thermocline, forming an intermediate nepheloid layer (INL). At the head of the bore (dense water), a vortex accompanied by strong vertical motion induced strong vertical sediment resuspension and a steep isothermal displacement. The rate of turbulent kinetic energy dissipation reached 10-6 W kg-1 at the head of the wave. A nonhydrostatic numerical simulation in a two-dimensional domain reproduced fine features associated with the run-up of an internal bore and the vortex motion at its head.

  2. Field size, length, and width distributions based on LACIE ground truth data. [large area crop inventory experiment

    NASA Technical Reports Server (NTRS)

    Pitts, D. E.; Badhwar, G.

    1980-01-01

    The development of agricultural remote sensing systems requires knowledge of agricultural field size distributions so that the sensors, sampling frames, image interpretation schemes, registration systems, and classification systems can be properly designed. Malila et al. (1976) studied the field size distribution for wheat and all other crops in two Kansas LACIE (Large Area Crop Inventory Experiment) intensive test sites using ground observations of the crops and measurements of their field areas based on current year rectified aerial photomaps. The field area and size distributions reported in the present investigation are derived from a representative subset of a stratified random sample of LACIE sample segments. In contrast to previous work, the obtained results indicate that most field-size distributions are not log-normally distributed. The most common field size observed in this study was 10 acres for most crops studied.

  3. EXPLAINING THE COEXISTENCE OF LARGE-SCALE AND SMALL-SCALE MAGNETIC FIELDS IN FULLY CONVECTIVE STARS

    SciTech Connect

    Yadav, Rakesh K.; Poppenhaeger, Katja; Wolk, Scott J.; Christensen, Ulrich R.; Gastine, Thomas; Morin, Julien; Reiners, Ansgar

    2015-11-10

    Despite the lack of a shear-rich tachocline region, low-mass fully convective (FC) stars are capable of generating strong magnetic fields, indicating that a dynamo mechanism fundamentally different from the solar dynamo is at work in these objects. We present a self-consistent three-dimensional model of magnetic field generation in low-mass FC stars. The model utilizes the anelastic magnetohydrodynamic equations to simulate compressible convection in a rotating sphere. A distributed dynamo working in the model spontaneously produces a dipole-dominated surface magnetic field of the observed strength. The interaction of this field with the turbulent convection in outer layers shreds it, producing small-scale fields that carry most of the magnetic flux. The Zeeman–Doppler-Imaging technique applied to synthetic spectropolarimetric data based on our model recovers most of the large-scale field. Our model simultaneously reproduces the morphology and magnitude of the large-scale field as well as the magnitude of the small-scale field observed on low-mass FC stars.

  4. Tunnel Boring Machine Technology for a Deeply Based Missile System. Volume I, Application Feasibility. Part 1.

    DTIC Science & Technology

    1980-08-01

    AD-A091 976 COLORADO SCHOOL OF MINES GOLDEN F/G 13/2 NNEL BORING MACHINE TECHNOLOGY FOR A DEEPLY BASED MISSILE SYS-ETC(U) .UA 80 G B CLARK. L...TR-79-120, Vol. I, Pt. 1 AFWL-TR- 79-120 Vol. I ~Pt. I TUNNEL BORING MACHINE TECHNOLOGY FOR A DEEPLY BASED MISSILE SYSTEM Volume I of 11 lApplication... BORING MACHINE TECHNOLOGY FOR A DEEPLY BASED MISSILE SYSTEM Final Report Vol I of II: Application Feasibility 6. PERFORMINGORO. REPORTNUMM Part I of 2 7

  5. Effect of Sputtering Parameters on Ta Coatings for Gun Bore Applications

    SciTech Connect

    Matson, Dean W.; McClanahan, Edwin D.; Rice, Joseph P.; Lee, Sabrina L.; Windover, Donald

    2000-11-30

    Tantalum offers a number of attractive properties for gun bore coating applications, including a high melting temperature, high ductility, and an environmentally friendly deposition method. However, vapor-deposited tantalum can appear in both the characteristic bcc phase found in the bulk material, and in a very brittle and less desirable 'beta' phase. Presence of the beta phase in bore coatings is considered undesirable because of its brittleness and resulting failure as the coating is stressed. A high-rate triode sputtering system with a cylindrical coating geometry was used to produce thick tantalum coatings on 4340 steel smooth bore cylindrical substrates.

  6. Tidal bores, turbulence and mixing above deep-ocean slopes

    NASA Astrophysics Data System (ADS)

    Winters, Kraig

    2016-11-01

    A tidally driven, stably-stratified turbulent boundary layer over supercritically sloping topography is simulated numerically using a spectral LES approach (Winters, 2015, 2016). The near boundary flow is characterized by quasi-periodic, bore-like motions, whose temporal signature is compared to the high-resolution ocean mooring data of van Haren (2006). The relatively thick bottom boundary layer remains stably stratified owing to the regular cycling of unmixed ambient fluid into the turbulent boundary layer and episodic expulsion events where fluid is ejected into the stratified interior. The effective diffusivity of the flow near the boundary is estimated by means of a synthetic dye tracer experiment. The average dissipation rate within the dye cloud is computed and combined with the diffusivity estimate to yield an overall mixing efficiency of 0.15. Both the estimated diffusivity and dissipation rates are in reasonable agreement with the microstructure observations of Kunze et al. (2012) when scaled to the environmental conditions at the Monterey and Soquel Canyons and to the values estimated by van Haren and Gostiaux (2012) above the sloping bottom of the Great Meteor Seamount in the Canary Basin.

  7. Braided composite bore evacuator chambers for tank cannons

    NASA Technical Reports Server (NTRS)

    Wheeler, Philip C.

    1990-01-01

    Typically, continuous filament composite components are fabricated using a filament winding technique. In this operation, fibers are introduced to a rotating mandrel while a guide holding the material traverses back and forth to place the material in a helical pattern over the surface of the mandrel. This procedure is continued until complete coverage is obtained. An alternative method for fabricating continuous filament composite components is braiding. In the braiding operation a mandrel is traversed through the center of the braider while 144 strands of material traverse around a carrier ring. As the fibers are applied to a mandrel surface, 72 carriers holding the fibers travel clockwise, while another 72 carriers travel counterclockwise to interlock fibers. An additional 72 carriers located on the back of the braider introduce longitudinal fibers to the composite giving the composite lateral strength. The goal of using the braider is to reduce production time by simultaneously applying 144 strands of material onto a mandrel as opposed to the four-strand wrapping most filament winding techniques offer. Benefits to braiding include the ability to (1) introduce longitudinal fibers to the composite structure; (2) fabricate non-symmetric components without using complex functions to produce full coverage; and (3) produce a component with a higher degree of damage tolerance due to the interlocking of fibers. The fabrication of bore evacuator chambers for a tank cannon system is investigated by utilizing a 144 carrier braiding machine, an industrial robot, and a resin applicator system.

  8. Remotely variable multiple bore ram system and method

    SciTech Connect

    Carnahan, D.A.

    1989-05-02

    A ram assembly is described for use in a ram type blow out preventer, comprising: a thrust rod defining a longitudinal axis; a ram block body interconnected to the rod and defining a vertical cylindrical and normal to the longitudinal axis of the thrust rod; a ram shoe preselected from a plurality of parts thereof having different bores, the shoe having a load shoulder with a vertical cylindrical pin hole extending through the shoulder, and further having pipe faces and a seal disposed between the pipe faces and circumscribing the shoe; and a lock pin means having a collet hole disposed in one end for releasably interconnecting the ram shoe and the ram block when the lock pin means, the lock pin hole, and the pin hole are coaligned in vertical registry with the lock pin means disposed in the lock pin hole and the pin hole. The patent also describes a method using a running tool suspended from a drill hole string for changing from a first location a pair of ram shoes releasably interconnected by pins to respective rams of a ram type blow out preventer.

  9. Design of optoelectronic imaging system with high resolution and large field-of-view based on dual CMOS

    NASA Astrophysics Data System (ADS)

    Cheng, Hanglin; Hao, Qun; Hu, Yao; Cao, Jie; Wang, Shaopu; Li, Lin

    2016-10-01

    With the advantages of high resolution, large field of view and compacted size, optoelectronic imaging sensors are widely used in many fields, such as robot's navigation, industrial measurement and remote sensing. Many researchers pay more attention to improve the comprehensive performances of imaging sensors, including large field of view (FOV), high resolution, compact size and high imaging efficiency, etc. One challenge is the tradeoff between high resolution and large field of view simultaneously considering compacted size. In this paper, we propose an optoelectronic imaging system combining the lenses of short focal length and long focal length based on dual CMOS to simulate the characters of human eyes which observe object within large FOV in high resolution. We design and optimize the two lens, the lens of short focal length is used to search object in a wide field and the long one is responsible for high resolution imaging of the target area. Based on a micro-CMOS imaging sensor with low voltage differential transmission technology-MIPI (Mobile Industry Processor Interface), we design the corresponding circuits to realize collecting optical information with high speed. The advantage of the interface is to help decreasing power consumption, improving transmission efficiency and achieving compacted size of imaging sensor. Meanwhile, we carried out simulations and experiments to testify the optoelectronic imaging system. The results show that the proposed method is helpful to improve the comprehensive performances of optoelectronic imaging sensors.

  10. Large-Scale Velocity Fields and Small-Scale Magnetic Fields During the Maximum of Solar Cycle 22

    DTIC Science & Technology

    1992-11-01

    abstract describing this process of filament formation is published in the Proceedings of IAU Colloquium 133 on Eruptive flares held in Iguazu Argentina...July 1991 and at the IAU Coloquium on Eruptive Flares in Iguazu , Argentina, August 1991. 17 3.4 THE ROLE OF CANCELLING MAGNETIC FIELDS IN THE BUILD-UP TO...Jackson, 2-6 August 1991, Iguazu , Argentina. 2. Invited Review Paper on ’The Formation of Prominences’ for Solar Physics, by S.F. Martin and C

  11. On the statistics of biased tracers in the Effective Field Theory of Large Scale Structures

    SciTech Connect

    Angulo, Raul; Fasiello, Matteo; Senatore, Leonardo; Vlah, Zvonimir E-mail: matteorf@stanford.edu E-mail: zvlah@stanford.edu

    2015-09-01

    With the completion of the Planck mission, in order to continue to gather cosmological information it has become crucial to understand the Large Scale Structures (LSS) of the universe to percent accuracy. The Effective Field Theory of LSS (EFTofLSS) is a novel theoretical framework that aims to develop an analytic understanding of LSS at long distances, where inhomogeneities are small. We further develop the description of biased tracers in the EFTofLSS to account for the effect of baryonic physics and primordial non-Gaussianities, finding that new bias coefficients are required. Then, restricting to dark matter with Gaussian initial conditions, we describe the prediction of the EFTofLSS for the one-loop halo-halo and halo-matter two-point functions, and for the tree-level halo-halo-halo, matter-halo-halo and matter-matter-halo three-point functions. Several new bias coefficients are needed in the EFTofLSS, even though their contribution at a given order can be degenerate and the same parameters contribute to multiple observables. We develop a method to reduce the number of biases to an irreducible basis, and find that, at the order at which we work, seven bias parameters are enough to describe this extremely rich set of statistics. We then compare with the output of an N-body simulation where the normalization parameter of the linear power spectrum is set to σ{sub 8} = 0.9. For the lowest mass bin, we find percent level agreement up to k≅ 0.3 h Mpc{sup −1} for the one-loop two-point functions, and up to k≅ 0.15 h Mpc{sup −1} for the tree-level three-point functions, with the k-reach decreasing with higher mass bins. This is consistent with the theoretical estimates, and suggests that the cosmological information in LSS amenable to analytical control is much more than previously believed.

  12. On the statistics of biased tracers in the Effective Field Theory of Large Scale Structures

    SciTech Connect

    Angulo, Raul; Fasiello, Matteo; Senatore, Leonardo; Vlah, Zvonimir

    2015-09-09

    With the completion of the Planck mission, in order to continue to gather cosmological information it has become crucial to understand the Large Scale Structures (LSS) of the universe to percent accuracy. The Effective Field Theory of LSS (EFTofLSS) is a novel theoretical framework that aims to develop an analytic understanding of LSS at long distances, where inhomogeneities are small. We further develop the description of biased tracers in the EFTofLSS to account for the effect of baryonic physics and primordial non-Gaussianities, finding that new bias coefficients are required. Then, restricting to dark matter with Gaussian initial conditions, we describe the prediction of the EFTofLSS for the one-loop halo-halo and halo-matter two-point functions, and for the tree-level halo-halo-halo, matter-halo-halo and matter-matter-halo three-point functions. Several new bias coefficients are needed in the EFTofLSS, even though their contribution at a given order can be degenerate and the same parameters contribute to multiple observables. We develop a method to reduce the number of biases to an irreducible basis, and find that, at the order at which we work, seven bias parameters are enough to describe this extremely rich set of statistics. We then compare with the output of an N-body simulation where the normalization parameter of the linear power spectrum is set to σ8 = 0.9. For the lowest mass bin, we find percent level agreement up to k ≃ 0.3 h Mpc–1 for the one-loop two-point functions, and up to k ≃ 0.15 h Mpc–1 for the tree-level three-point functions, with the k-reach decreasing with higher mass bins. In conclusion, this is consistent with the theoretical estimates, and suggests that the cosmological information in LSS amenable to analytical control is much more than previously believed.

  13. On the statistics of biased tracers in the Effective Field Theory of Large Scale Structures

    DOE PAGES

    Angulo, Raul; Fasiello, Matteo; Senatore, Leonardo; ...

    2015-09-09

    With the completion of the Planck mission, in order to continue to gather cosmological information it has become crucial to understand the Large Scale Structures (LSS) of the universe to percent accuracy. The Effective Field Theory of LSS (EFTofLSS) is a novel theoretical framework that aims to develop an analytic understanding of LSS at long distances, where inhomogeneities are small. We further develop the description of biased tracers in the EFTofLSS to account for the effect of baryonic physics and primordial non-Gaussianities, finding that new bias coefficients are required. Then, restricting to dark matter with Gaussian initial conditions, we describemore » the prediction of the EFTofLSS for the one-loop halo-halo and halo-matter two-point functions, and for the tree-level halo-halo-halo, matter-halo-halo and matter-matter-halo three-point functions. Several new bias coefficients are needed in the EFTofLSS, even though their contribution at a given order can be degenerate and the same parameters contribute to multiple observables. We develop a method to reduce the number of biases to an irreducible basis, and find that, at the order at which we work, seven bias parameters are enough to describe this extremely rich set of statistics. We then compare with the output of an N-body simulation where the normalization parameter of the linear power spectrum is set to σ8 = 0.9. For the lowest mass bin, we find percent level agreement up to k ≃ 0.3 h Mpc–1 for the one-loop two-point functions, and up to k ≃ 0.15 h Mpc–1 for the tree-level three-point functions, with the k-reach decreasing with higher mass bins. In conclusion, this is consistent with the theoretical estimates, and suggests that the cosmological information in LSS amenable to analytical control is much more than previously believed.« less

  14. Dynamic wave field synthesis: enabling the generation of field distributions with a large space-bandwidth product.

    PubMed

    Kamau, Edwin N; Heine, Julian; Falldorf, Claas; Bergmann, Ralf B

    2015-11-02

    We present a novel approach for the design and fabrication of multiplexed computer generated volume holograms (CGVH) which allow for a dynamic synthesis of arbitrary wave field distributions. To achieve this goal, we developed a hybrid system that consists of a CGVH as a static element and an electronically addressed spatial light modulator as the dynamic element. We thereby derived a new model for describing the scattering process within the inhomogeneous dielectric material of the hologram. This model is based on the linearization of the scattering process within the Rytov approximation and incorporates physical constraints that account for voxel based laser-lithography using micro-fabrication of the holograms in a nonlinear optical material. In this article we demonstrate that this system basically facilitates a high angular Bragg selectivity on the order of 1°. Additionally, it allows for a qualitatively low cross-talk dynamic synthesis of predefined wave fields with a much larger space-bandwidth product (SBWP ≥ 8.7 × 10(6)) as compared to the current state of the art in computer generated holography.

  15. Largely defocused probe scanning transmission electron microscopy for imaging local modulation of strain field in a hetero interface

    SciTech Connect

    Kim, Suhyun Jung, Younheum; Kim, Joong Jung; Lee, Sunyoung; Lee, Haebum; Oshima, Yoshifumi

    2014-10-13

    We present an innovative method for characterizing the strain field in three dimensions in a hetero interface. Largely defocused probe scanning transmission electron microscopy (LDP-STEM) was employed for imaging the inhomogeneous strain field in a germanium (Ge) layer deposited on a silicon (Si) substrate. In the LDP-STEM image, Ge-atomic columns that are relaxed or strained to the Si substrate in the Si/Ge hetero interface were observed to be distinguishable, allowing for the qualitative characterization of the coherency of the crystal growth. Our results revealed that the strain field is locally modulated along the in-plane direction in the Si/Ge hetero interface.

  16. Strong and large area field enhancement outside a microcavity due to propagating surface plasmons and standing wave effect

    NASA Astrophysics Data System (ADS)

    Wang, Meng; Wang, Bin; Sun, Xin; Li, Haoyu; Wang, Feng; Zhang, Yunxia; Huang, Senpeng; Xu, Xiaoxuan; Wang, Yufang; Zhang, Cunzhou

    2016-10-01

    We investigated the optical property of periodic inverted pyramidal microcavities and observed large area field enhancement outside a cavity when the incident wavelength and structure parameters match certain relations. The mechanism of this phenomenon has been studied. Propagating surface plasmons and the standing wave effect both contribute to the field enhancement outside the cavity. The relations between the incident wavelength and structure parameters have been clarified. Based on the relations, one can control the field enhancement outside the cavity for a specific laser wavelength.

  17. Detection of large thermal vibration for Cu atoms in tetrahedrite by high-angle annular dark-field imaging

    NASA Astrophysics Data System (ADS)

    Prasad Mishra, Tara; Koyano, Mikio; Oshima, Yoshifumi

    2017-04-01

    Tetrahedrite (Cu12Sb4S13) is a new type of thermoelectric material with an extremely low thermal conductivity attributed to the anomalous large thermal vibration of specific Cu sites. The tetrahedrite crystal was observed from the [111] direction by high-angle annular dark-field (HAADF) imaging and the image intensity was found to be 64% lower at specific sites. This could be explained by the blurring of the intensity distribution owing to a large atomic displacement, suggesting that anomalous large thermal vibrations at specific sites in the crystal can be distinguished in HAADF images.

  18. Field computation for a neutrino detector magnet: the effect of small gaps in large bodies

    SciTech Connect

    Turner, L.R.

    1996-11-01

    The presence of small features such as thin gaps in a large magnetic object presents difficulties for numerical computation. The proposed MINOS neutrino detector displays just such a difficulty, small ({approx}1 mm) but unavoidable gaps in the large ({approx}8 m) iron of the magnets. This paper describes the process of obtaining adequate precision while modeling those gaps.

  19. Near-Earth Magnetic Field Effects of Large-Scale Magnetospheric Currents

    NASA Technical Reports Server (NTRS)

    Luehr, Hermann; Xiong, Chao; Olsen, Nils; Le, Guan

    2016-01-01

    Magnetospheric currents play an important role in the electrodynamics of near- Earth space. This has been the topic of many space science studies. Here we focus on the magnetic fields they cause close to Earth. Their contribution to the geomagnetic field is the second largest after the core field. Significant progress in interpreting the magnetic fields from the different sources has been achieved thanks to magnetic satellite missions like Ørsted, CHAMP and now Swarm. Of particular interest for this article is a proper representation of the magnetospheric ring current effect. Uncertainties in modelling its effect still produce the largest residuals between observations and present-day geomagnetic field models. A lot of progress has been achieved so far, but there are still open issues like the characteristics of the partial ring current. Other currents discussed are those flowing in the magnetospheric tail. Also their magnetic contribution at LEO orbits is non-negligible. Treating them as an independent source is a more recent development, which has cured some of the problems in geomagnetic field modelling. Unfortunately there is no index available for characterizing the tail current intensity. Here we propose an approach that may help to properly quantify the magnetic contribution from the tail current for geomagnetic field modelling. Some open questions that require further investigation are mentioned at the end.

  20. Near-Earth Magnetic Field Effects of Large-Scale Magnetospheric Currents

    NASA Astrophysics Data System (ADS)

    Lühr, Hermann; Xiong, Chao; Olsen, Nils; Le, Guan

    2017-03-01

    Magnetospheric currents play an important role in the electrodynamics of near-Earth space. This has been the topic of many space science studies. Here we focus on the magnetic fields they cause close to Earth. Their contribution to the geomagnetic field is the second largest after the core field. Significant progress in interpreting the magnetic fields from the different sources has been achieved thanks to magnetic satellite missions like Ørsted, CHAMP and now Swarm. Of particular interest for this article is a proper representation of the magnetospheric ring current effect. Uncertainties in modelling its effect still produce the largest residuals between observations and present-day geomagnetic field models. A lot of progress has been achieved so far, but there are still open issues like the characteristics of the partial ring current. Other currents discussed are those flowing in the magnetospheric tail. Also their magnetic contribution at LEO orbits is non-negligible. Treating them as an independent source is a more recent development, which has cured some of the problems in geomagnetic field modelling. Unfortunately there is no index available for characterising the tail current intensity. Here we propose an approach that may help to properly quantify the magnetic contribution from the tail current for geomagnetic field modelling. Some open questions that require further investigation are mentioned at the end.