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

    M.A. Ebadian

    1999-01-01

    The decontamination and characterization of large-bore pipe is difficult because of the various geometries and diameters of pipe and its different material types. A robust decontamination system must be capable of adapting to different pipe diameters (project scope is 6 inches to 24 inches), cleaning surfaces with various surface conditions and material types (i.e., painted, rusted, carbon steel, or stainless steel), and be cost-effective to operate and maintain. The characterization system must be capable of handling the different pipe parameters and detecting contamination on the inside and outside surfaces. It must also operate in a cost-effective manner. Current technology options do not provide a robust system to meet these objectives. The purpose of this project is to verify the need for this technology through determining quantities of pipe available for decontamination (completed FY97), perform a technology screening process to select technologies for decontamination (completed FY97) and characterization (completed FY98), perform treatability studies to collect required performance data (completed FY97), and design and fabricate a prototype system to decontaminate and characterize the internal and external surfaces of large-bore pipe. A field mobile system capable of performing decontamination and characterization operations will be the main deliverable for this project. A summary of activities completed during FY97 is provided to understand the project development and implementation process.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. 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

  14. 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

  15. DETAIL VIEW OF LARGE BORE HOLE, SHOWING TRIANGULAR SHAPE FORMED ...

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

    DETAIL VIEW OF LARGE BORE HOLE, SHOWING TRIANGULAR SHAPE FORMED BY CHISEL METHOD OF DRILLING - Granite Hill Plantation, Quarry No. 3, South side of State Route 16, 1.3 miles northeast east of Sparta, Sparta, Hancock County, GA

  16. 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.

  17. A prospective randomized comparison of type of nephrostomy drainage following percutaneous nephrostolithotomy: large bore versus small bore versus tubeless.

    PubMed

    Desai, Mahesh R; Kukreja, Rajesh A; Desai, Mihir M; Mhaskar, Sumeet S; Wani, Kishore A; Patel, Snehal H; Bapat, Sharad D

    2004-08-01

    We compared postoperative outcomes among tubeless, conventional large bore nephrostomy drainage and small bore nephrostomy drainage following percutaneous nephrostolithotomy (PCNL) in a prospective randomized fashion. Between January and June 2001, 30 patients undergoing PCNL were randomized to receive conventional large bore (20Fr) nephrostomy drainage (group 1, 10 patients), small bore (9Fr) nephrostomy drainage (group 2, 10 patients) or no nephrostomy drainage (group 3, 10 patients). Inclusion criteria included a single subcostal tract, uncomplicated procedure, normal preoperative renal function and complete stone clearance. Factors compared among the 3 groups were postoperative analgesia requirement, urinary extravasation, duration of hematuria, duration of urinary leak, decrease in hematocrit and hospital stay. The postoperative analgesic requirement was significantly higher in group 1 (217 mg) compared to groups 2 (140 mg, p <0.05) and 3 (87.5 mg, p <0.0001). Patients in group 3 had a significantly shorter duration (4.8 hours) of urinary leak through the percutaneous renal tract compared to patients in groups 1 (21.4 hours, p <0.05) and 2 (13.2 hours, p <0.05). Hospital stay was significantly shorter in group 3 (3.4 days) compared to groups 1 (4.4 days, p <0.05) and 2 (4.3 days, p <0.05). All 3 groups were similar in terms of operative time, duration of hematuria and decrease in hematocrit. Postoperative ultrasound did not reveal significant urinary extravasation in any case. Tubeless PCNL is associated with the least postoperative pain, urinary leakage and hospital stay. Small bore nephrostomy drainage may be a reasonable option in patients in whom the incidence of stent dysuria is likely to be higher.

  18. 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.

  19. Detailed design of the large-bore 8 T superconducting magnet for the NAFASSY test facility

    NASA Astrophysics Data System (ADS)

    Corato, V.; Affinito, L.; Anemona, A.; Besi Vetrella, U.; Di Zenobio, A.; Fiamozzi Zignani, C.; Freda, R.; Messina, G.; Muzzi, L.; Perrella, M.; Reccia, L.; Tomassetti, G.; Turtù, S.; della Corte, A.

    2015-03-01

    The ‘NAFASSY’ (NAtional FAcility for Superconducting SYstems) facility is designed to test wound conductor samples under high-field conditions at variable temperatures. Due to its unique features, it is reasonable to assume that in the near future NAFASSY will have a preeminent role at the international level in the qualification of long coiled cables in operative conditions. The magnetic system consists of a large warm bore background solenoid, made up of three series-connected grading sections obtained by winding three different Nb3Sn Cable-in-Conduit Conductors. Thanks to the financial support of the Italian Ministry for University and Research the low-field coil is currently under production. The design has been properly modified to allow the system to operate also as a stand-alone facility, with an inner bore diameter of 1144 mm. This magnet is able to provide about 7 T on its axis and about 8 T close to the insert inner radius, giving the possibility of performing a test relevant for large-sized NbTi or medium-field Nb3Sn conductors. The detailed design of the 8 T magnet, including the electro-magnetic, structural and thermo-hydraulic analysis, is here reported, as well as the production status.

  20. 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.

  1. 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.

  2. Large or small bore, push or pull: a comparison of three classes of percutaneous fluoroscopic gastrostomy catheters.

    PubMed

    Kuo, Yuo-Chen; Shlansky-Goldberg, Richard D; Mondschein, Jeffrey I; Stavropoulos, S William; Patel, Aalpen A; Solomon, Jeffrey A; Soulen, Michael C; Kwak, Andrew; Itkin, Maxim; Chittams, Jesse L; Trerotola, Scott O

    2008-04-01

    To compare the tube performance and complication rates of small-bore, large-bore push-type, and large-bore pull-type gastrostomy catheters. A total of 160 patients (74 men, 86 women; mean age, 66.9 years, range, 22-95 y) underwent percutaneous fluoroscopic gastrostomy placement between January 2004 and March 2006. Choice of catheter was based on the preference of the attending radiologist. Data were collected retrospectively with institutional review board approval. Radiology reports provided information on the catheter, indication for gastrostomy, technical success, and immediate outcome. Chart review provided data on medical history, postprocedural complications, progress to feeding goal, and clinical outcomes. Statistical analysis was performed to compare the three classes of gastrostomy catheters. All 160 catheters were placed successfully. Patients who received small-bore catheters (14 F; n = 88) had significantly more tube complications (17% vs 5.6%) and were less likely to meet their feeding goal (P = .035) compared with patients with large-bore catheters (20 F; n = 72). No difference was observed in terms of major or minor complications. Large-bore push-type (n = 14) and pull-type catheters (n = 58) were similar in terms of complication rates. Patients who received large-bore push-type catheters achieved their feeding goals in significantly less time than those with large-bore pull-type catheters (average, 3.8 days vs 6.0 days; P = .04). Patients who received small-bore gastrostomy catheters are significantly more prone to tube dysfunction. Large-bore catheters should be preferentially used, with push-type catheters performing better with regard to the time to achieve feeding goal.

  3. 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.

  4. 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.

  5. 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.

  6. Large-bore copper vapor amplifier with slow buffer gas pumping

    NASA Astrophysics Data System (ADS)

    Gamazeyschikov, A. M.; Motovilov, Sergei A.; Savchenko, Yu. I.; Yudin, A. A.; Yatsenko, Boris P.; Bogdanov, V. V.; Vasilevsky, M. A.; Vodovozov, V. M.; Kasatkin, V. I.; Krotov, I. P.; Makarevich, A. A.; Yankin, E. G.

    2002-03-01

    The design of a large-bore copper vapor laser amplifier (CVA) intended for the application to high-power laser systems operating in the 'master oscillator ('MO-amplifier') mode is described. The discharge volume of the amplifier laser head is 70 mm in diameter and about 2000 mm in length. The results of experimental studies of the CVA operating in the lasing mode at a pulse repetition rate of 4 - 6 kHz and a buffer gas pressure of 30 - 80 Torr are presented in the paper. Stable operation of the CVA was achieved at an output power of 100 +/- 5 W and approximately 1% efficiency.

  7. 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.

  8. 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.

  9. 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.

  10. Report on the development of the large-bore powder gun for the Nevada Test Site

    SciTech Connect

    B.J. Jensen

    2009-03-01

    Experiments are needed to locate phase boundaries and to provide both Hugoniot data and off-Hugoniot data (such as principle isentrope, refreezing, dynamic strength, etc.) achieved through complex loading paths. The objective of the current work was to de- velop a large bore (3.5 inch or greater) powder gun capable of accelerating projectiles to moderately high velocities exceeding 2 km/s for impact experiments. A total of 24 ex- periments were performed to measure the projectile velocity, breech strain, and projectile tilt to demonstrate the performance of the gun up to the maximum breech capacity of 16 pounds of propellant. Physics experiments using a multislug method were performed to obtain sound speed and Hugoniot for shocked cerium metal and to demonstrate the ability of the large bore gun to conduct well-defined, plate-impact experiments. In addition, six experiments were performed on the prototype containment system to examine the ability of the launcher and containment system to withstand the impact event and contain the propellant gases and impact debris postshot. The data presented here were essential for qualification of the launcher for experiments to be conducted at the U1a complex of the Nevada Test Site.

  11. 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.

  12. 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.

  13. 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.

  14. Large-bore nitinol stents for malignant superior vena cava syndrome: factors influencing outcome.

    PubMed

    Maleux, Geert; Gillardin, Patrick; Fieuws, Steffen; Heye, Sam; Vaninbroukx, Johan; Nackaerts, Kristiaan

    2013-09-01

    The purpose of this article is to retrospectively evaluate the technical and clinical outcomes of large-bore nitinol stents for treating malignant superior vena cava syndrome. In addition, we analyzed factors potentially influencing the outcome. Over a 7-year period, 78 consecutive patients presented with superior vena cava syndrome related to primary lung tumor (n=62) or malignant lymphadenopathies (n=16). The factors analyzed were Kishi score at admission, tumor type, and need for an additional balloon-expandable stent. Technical success was obtained in all but one patient (99%), who presented with a stent migration immediately after insertion. In 17 patients (22%), an additional balloon-expandable stent was needed for complete expansion of the nitinol stent. For patients with symptomatic malignant lymphadenopathies or primary lung tumor, overall survival rates were 50% (n=8) and 54% (n=34), respectively, at 6 months and 19% (n=3) and 34% (n=21), respectively, at 12 months (p=0.376). There was no difference in survival as a function of the Kishi score (p=0.80) or of the placement of an additional balloon-expandable stent (p=0.35). Finally, reocclusion events were noted in patients both with (n=1) and without (n=7) a balloon-expandable stent. Large-bore nitinol stents are highly effective for malignant superior vena cava syndrome. The survival rates of patients with caval vein stenosis due to either the primary tumor or secondary enlarged adenopathies were equal. An additional balloon-expandable stent was required in 22% of cases owing to incomplete expansion of the nitinol stent but was not associated with higher thrombosis rate.

  15. On resonant generation of internal waves: solitary waves, dissipationless bores, and large topographically trapped disturbances

    NASA Astrophysics Data System (ADS)

    Stastna, M.; Peltier, W. R.

    2003-04-01

    In this talk we will present results of direct numerical simulations of the resonant generation of internal waves by flow over simple two-dimensional topography. These are motivated by recent simulations of the flow in Knight Inlet, B.C., Canada by Stastna and Peltier (2002, submitted to Proceedings of the Royal Society), which revealed upstream propagating, breaking internal solitary waves over a large range of inflow velocities. As the topography at Knight Inlet is of large amplitude (nearly one half of the water column) the simulations reported on in the present focus on less extreme topography. Furthermore, following the recent classification of limits on internal solitary wave amplitude by Stastna and Lamb (2002, Physics of Fluids, 14, 2987), we focus on a density profile for which wave amplitude is bounded by the so-called conjugate flow limit (the limit of dissipationless bores). We observe a wide range of large, coherent structures, propagating both up and downstream. We will present examples of these structures, as well as discuss their theoretical description, where one is available. A particularly novel aspect of our simulations is the existence of a parameter range for which extremely large, highly nonlinear, topographically trapped disturbances are genereated. To the best of our knowledge these structures have not been reported on in the literature in the past. Finally we will comment on when one expects breaking (as opposed to the above-mentioned laminar structures) to dominate the flow.

  16. 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.

  17. Ethanol and (-)-a-pinene: attractant kairomones for some large wood-boring beetles in Southeastern USA

    Treesearch

    Daniel R. Miller

    2006-01-01

    Ethanol and a-pinene were tested as attractants for large wood-boring pine beetles in Alabama, Florida, Georgia, North Carolina, and South Carolina in 2002-2004. Multiple-funnel traps baited with (-)-a-pinene (released at about 2 g/d at 25-28°C) were attractive to the following Cerambycidae: Acanthocinus nodosus, A. obsoletus, Arhopalus...

  18. 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

  19. Supersonic Virtual Valve Design for Numerical Simulation of a Large-Bore Natural Gas Engine

    SciTech Connect

    Kim, G.-H.; Kirkpatrick, A.; Mitchell, C.

    2007-10-01

    In many applications of supersonic injection devices, three-dimensional computation that can model a complex supersonic jet has become critical. However, in spite of its increasing necessity, it is computationally costly to capture the details of supersonic structures in intricate three-dimensional geometries with moving boundaries. In large-bore stationary natural gas fueled engine research, one of the most promising mixing enhancement technologies currently used for natural gas engines is high-pressure fuel injection. Consequently, this creates considerable interest in three-dimensional computational simulations that can examine the entire injection and mixing process in engines using high-pressure injection and can determine the impact of injector design on engine performance. However, the cost of three-dimensional engine simulations-including a moving piston and the kinetics of combustion and pollutant production quickly becomes considerable in terms of simulation time requirements. One limiting factor is the modeling of the small length scales of the poppet valve flow. Such length scales can be three orders of magnitude smaller than cylinder length scales. The objective of this paper is to describe the development of a methodology for the design of a simple geometry supersonic virtual valve that can be substituted in three-dimensional numerical models for the complex shrouded poppet valve injection system actually installed in the engine to be simulated.

  20. A large bore-direct injection high efficiency nebulizer for inductively coupled plasma spectrometry

    PubMed

    Acon; McLean; Montaser

    2000-04-15

    A large bore-direct injection high efficiency nebulizer (IB-DIHEN) is introduced that is less prone to capillary blockage and optimally operates at low nebulizer gas pressures compared with the conventional DIHEN used for inductively coupled plasma (ICP) spectrometries. The aerosol quality is examined using a two-dimensional phase Doppler particle analyzer (2D PDPA), and analytical figures of merits are acquired by ICP mass spectrometry. Compared with the DIHEN, the LB-DIHEN produces larger droplets, but the velocity distributions and mean droplet velocities are narrower and lower, respectively, providing longer residence times for the droplets in the plasma. High RF power (1500 W), low nebulizer gas flow rates (0.25-0.35 L/min), and low solution uptake rates (80-110 microL/min) are required to operate the LB-DIHEN at optimum conditions for ICPMS. Detection limits and sensitivities measured with the LB-DIHEN are superior to those of a conventional nebulizer-spray chamber combination, but precision is inferior. The performance of the LB-DIHEN is further explored in the determination of trace elements in an herbal extract.

  1. 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.

  2. 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.

  3. Ethanol and (-)-α-Pinene: Attractant Kairomones for Some Large Wood-Boring Beetles in Southeastern USA

    Treesearch

    Daniel R. Miller

    2006-01-01

    Ethanol and α-pinene were tested as attractants for large wood-boring pine beetles in Alabama, Florida, Georgia, North Carolina, and South Carolina in 2002 –2004. Multiple-funnel traps baited with (-)-α-pinene (released at about 2 g/d at 25–28 degrees C) were attractive to the following Cerambycidae: Acanthocinus nodosus,

  4. MAPS – a Magic Angle Positioning System for Enhanced Imaging in High-Field Small-Bore MRI

    PubMed Central

    Squires, Alexander; Chan, Kevin C.; Ho, Leon C.; Sigal, Ian A.; Jan, Ning-Jiun

    2016-01-01

    The “magic angle” MRI effect can enhance signal intensity in aligned collagenous structures oriented at approximately 55° with respect to the main magnetic field. The difficulty of positioning tissue inside closed-bore scanners has hampered magic angle use in research and clinics. An MRI-conditional mechatronic system has been developed to control sample orientation inside a 9.4T small bore MRI scanner. The system orients samples to within 0.5° and enables a 600% increase in tendon signal intensity. PMID:28713864

  5. MAPS - a Magic Angle Positioning System for Enhanced Imaging in High-Field Small-Bore MRI.

    PubMed

    Squires, Alexander; Chan, Kevin C; Ho, Leon C; Sigal, Ian A; Jan, Ning-Jiun; Tse, Zion Tsz Ho

    2016-03-01

    The "magic angle" MRI effect can enhance signal intensity in aligned collagenous structures oriented at approximately 55° with respect to the main magnetic field. The difficulty of positioning tissue inside closed-bore scanners has hampered magic angle use in research and clinics. An MRI-conditional mechatronic system has been developed to control sample orientation inside a 9.4T small bore MRI scanner. The system orients samples to within 0.5° and enables a 600% increase in tendon signal intensity.

  6. 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.

  7. Variability of the 0-3 Ma palaeomagnetic field observed from the Boring Volcanic Field of the Pacific Northwest

    NASA Astrophysics Data System (ADS)

    Lhuillier, Florian; Shcherbakov, Valeriy P.; Gilder, Stuart A.; Hagstrum, Jonathan T.

    2017-10-01

    The Boring Volcanic Field of the Pacific Northwest (USA), composed of more than 80 eruptive units ranging in age from 3200 to 60 ka, offers a unique possibility to investigate the variability of the Quaternary to late Neogene palaeomagnetic field. To complement previous work on palaeodirections, we conducted 240 absolute palaeointensity (API) experiments with the joint use of the continuous (Wilson) and stepwise (Thellier-Coe) double-heating protocol, along with 620 relative palaeointensity (RPI) experiments based on the pseudo-Thellier approach. We successfully determined absolute estimates for 12 independent eruptive units, as well as relative estimates for 47 out of 132 investigated sites. We compare these results with the existing database for the last 3 Myr and obtain an estimate of the relative variability in palaeointensity on the order of 40-45 per cent as a proxy for palaeosecular variation. API and RPI data suggest a possible asymmetry between normal and reverse polarities.

  8. 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.

  9. Lubrication of high-speed, large bore tapered-roller bearings

    NASA Technical Reports Server (NTRS)

    Parker, R. J.; Signer, H. R.

    1978-01-01

    The performance of 120.65-mm bore tapered-roller bearings was investigated at shaft speeds up to 15,000 rpm. Temperature distribution and bearing heat generation were determined as a function of shaft speed, radial and thrust loads, lubricant flow rate, and lubricant inlet temperature. Lubricant was supplied either by jets or by a combination of holes through the cone directly to the cone-rib contact and jets at the roller small-end side. Cone-rib lubrication significantly improved high-speed tapered-roller bearing performance, yielding lower cone-face temperatures and lower power loss and allowing lower lubricant flow rates for a given speed condition. Bearing temperatures increased with increased shaft speed and decreased with increased lubricant flow rate. Bearing power loss increased with increased shaft speed and increased lubricant flow rate.

  10. Lubrication of high-speed, large bore tapered-roller bearings

    NASA Technical Reports Server (NTRS)

    Parker, R. J.; Signer, H. R.

    1977-01-01

    The performance of 120.65-mm- (4.75-in.-) bore tapered-roller bearings was investigated at shaft speeds up to 15,000 rpm (18,000 DN). Temperature distribution and bearing heat generation were determined as a function of shaft speed, radial and thrust loads, lubricant flow rate, and lubricant inlet temperature. Lubricant was supplied either by jets or by a combination of holes through the cone directly to the cone-rib contact and jets at the roller small-end side. Cone-rib lubrication significantly improved high-speed tapered-roller bearing performance, yielding lower cone-face temperatures and lower power loss and allowing lower lubricant flow rates for a given speed condition. Bearing temperatures increased with increased shaft speed and decreased with increased lubricant flow rate. Bearing power loss increased with increased shaft speed and increased lubricant flow rate.

  11. 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.

  12. Ethanol and (-)-alpha-pinene: attractant kairomones for some large wood-boring beetles in southeastern USA.

    PubMed

    Miller, Daniel R

    2006-04-01

    Ethanol and alpha-pinene were tested as attractants for large wood-boring pine beetles in Alabama, Florida, Georgia, North Carolina, and South Carolina in 2002-2004. Multiple-funnel traps baited with (-)-alpha-pinene (released at about 2 g/d at 25-28 degrees C) were attractive to the following Cerambycidae: Acanthocinus nodosus, A. obsoletus, Arhopalus rusticus nubilus, Asemum striatum, Monochamus titillator, Prionus pocularis, Xylotrechus integer, and X. sagittatus sagittatus. Buprestis lineata (Buprestidae), Alaus myops (Elateridae), and Hylobius pales and Pachylobius picivorus (Curculionidae) were also attracted to traps baited with (-)-alpha-pinene. In many locations, ethanol synergized attraction of the cerambycids Acanthocinus nodosus, A. obsoletus, Arhopalus r. nubilus, Monochamus titillator, and Xylotrechus s. sagittatus (but not Asemum striatum, Prionus pocularis, or Xylotrechus integer) to traps baited with (-)-alpha-pinene. Similarly, attraction of Alaus myops, Hylobius pales, and Pachylobius picivorus (but not Buprestis lineata) to traps baited with (-)-alpha-pinene was synergized by ethanol. These results provide support for the use of traps baited with ethanol and (-)-alpha-pinene to detect and monitor common large wood-boring beetles from the southeastern region of the USA at ports-of-entry in other countries, as well as forested areas in the USA.

  13. Endurance tests with large-bore tapered-roller bearings to 2.2 million DN

    NASA Technical Reports Server (NTRS)

    Parker, R. J.; Signer, H. R.; Pinel, S. I.

    1981-01-01

    Endurance life tests were run with standard design and optimized high-speed design 120.65-mm-(4.750-in.-) bore tapered-roller bearings at shaft speeds of 12,500 and 18,500 rpm, respectively. Standard design bearings of vacuum melted AISI 4320 and CBS-1000M, and high-speed design bearings of CBS-1000M and through-hardened AISI M-50 were run under heavy combined radial and thrust load until fatigue failure or until a preset cutoff time of 1100 hours was reached. Standard design bearings made from CBS 1000M material ran to a 10 percent life approximately six times rated catalog life. Twelve identical bearings of AISI 4320 material ran to ten times rated catalog life without failure. Cracking and fracture of the cones of AISI M-50 high-speed design bearings occurred at 18,500 rpm due to high tensile hoop stresses. Four CBS 1000M high-speed design bearings ran to twenty-four times rated catalog life without any spalling, cracking or fracture failures.

  14. 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.

  15. 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.

  16. Acoustic field characterization of a clinical magnetic resonance-guided high-intensity focused ultrasound system inside the magnet bore.

    PubMed

    Kothapalli, Satya V V N; Altman, Michael B; Partanen, Ari; Wan, Leighton; Gach, H Michael; Straube, William; Hallahan, Dennis E; Chen, Hong

    2017-09-01

    With the expanding clinical application of magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU), acoustic field characterization of MR-HIFU systems is needed for facilitating regulatory approval and ensuring consistent and safe power output of HIFU transducers. However, the established acoustic field measurement techniques typically use equipment that cannot be used in a magnetic resonance imaging (MRI) suite, thus posing a challenge to the development and execution of HIFU acoustic field characterization techniques. In this study, we developed and characterized a technique for HIFU acoustic field calibration within the MRI magnet bore, and validated the technique with standard hydrophone measurements outside of the MRI suite. A clinical Philips MR-HIFU system (Sonalleve V2, Philips, Vantaa, Finland) was used to assess the proposed technique. A fiber-optic hydrophone with a long fiber was inserted through a 24-gauge angiocatheter and fixed inside a water tank that was placed on the HIFU patient table above the acoustic window. The long fiber allowed the hydrophone control unit to be placed outside of the magnet room. The location of the fiber tip was traced on MR images, and the HIFU focal point was positioned at the fiber tip using the MR-HIFU therapy planning software. To perform acoustic field mapping inside the magnet, the HIFU focus was positioned relative to the fiber tip using an MRI-compatible 5-axis robotic transducer positioning system embedded in the HIFU patient table. To perform validation measurements of the acoustic fields, the HIFU table was moved out of the MRI suite, and a standard laboratory hydrophone measurement setup was used to perform acoustic field measurements outside the magnetic field. The pressure field scans along and across the acoustic beam path obtained inside the MRI bore were in good agreement with those obtained outside of the MRI suite. At the HIFU focus with varying nominal acoustic powers of 10-500 W, the

  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. High-Field Open versus Short-Bore Magnetic Resonance Imaging of the Spine: A Randomized Controlled Comparison of Image Quality

    PubMed Central

    Zimmermann, Elke; Asbach, Patrick; Diederichs, Gerd; Wetz, Christoph; Siebert, Eberhard; Wagner, Moritz; Hamm, Bernd; Dewey, Marc

    2013-01-01

    Background The purpose of the present study was to compare the image quality of spinal magnetic resonance (MR) imaging performed on a high-field horizontal open versus a short-bore MR scanner in a randomized controlled study setup. Methods Altogether, 93 (80% women, mean age 53) consecutive patients underwent spine imaging after random assignement to a 1-T horizontal open MR scanner with a vertical magnetic field or a 1.5-T short-bore MR scanner. This patient subset was part of a larger cohort. Image quality was assessed by determining qualitative parameters, signal-to-noise (SNR) and contrast-to-noise ratios (CNR), and quantitative contour sharpness. Results The image quality parameters were higher for short-bore MR imaging. Regarding all sequences, the relative differences were 39% for the mean overall qualitative image quality, 53% for the mean SNR values, and 34–37% for the quantitative contour sharpness (P<0.0001). The CNR values were also higher for images obtained with the short-bore MR scanner. No sequence was of very poor (nondiagnostic) image quality. Scanning times were significantly longer for examinations performed on the open MR scanner (mean: 32±22 min versus 20±9 min; P<0.0001). Conclusions In this randomized controlled comparison of spinal MR imaging with an open versus a short-bore scanner, short-bore MR imaging revealed considerably higher image quality with shorter scanning times. Trial Registration ClinicalTrials.gov NCT00715806 PMID:24391767

  19. 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

  20. Comparison of the efficacy of small and large-bore thoracostomy tubes for pleural space evacuation in canine cadavers.

    PubMed

    Fetzer, Tara J; Walker, Julie M; Bach, Jonathan F

    2017-05-01

    To determine if there is a difference in the amounts of air (A), low-viscosity fluid (LV), or high-viscosity fluid (HV) that can be aspirated from the pleural cavity of canine cadavers using small-bore (SB) or large-bore (LB) thoracostomy tubes. Prospective experimental ex vivo study. University teaching hospital. Thirty-six canine cadavers. Each cadaver was randomly assigned to 1 of 6 groups (SB-A, LB-A, SB-LV, LB-LV, SB-HV, LB-HV). In each cadaver bilateral thoracostomy tubes (either SB or LB) were placed and 20 mL/kg of air, LV fluid, or HV fluid was instilled via 1 thoracostomy tube. Both tubes were aspirated and the volume aspirated was recorded and analyzed as a percentage of instilled air or fluid volume. The procedure was repeated on the contralateral hemithorax. There was no significant difference in air or fluid recovery when SB and LB groups were compared. Median (range) air recovery volumes in the SB-A and LB-A groups were 101.5% (94.4-115.8%) and 102.8% (94.1-107.8%), respectively (P = 0.898). Recovery of LV fluid was 93.5% (79.2-99.0%) for SB-LV and 85.8% (77.1-101.8%) for LB-LV cadavers (P = 0.305) and recovery percentages of HV fluid were 92.6% (86.1-96.2%) and 91.4% (74.2-96.4%) for SB-HV and LB-HV groups, respectively (P > 0.999). There was no significant difference between SB and LB groups when all substances were combined (94.1% [79.2-115.8%] and 93.5% [74.2-107.8%], respectively, P = 0.557). SB and LB thoracostomy tubes demonstrated similar efficacy in removing known amounts of air, LV fluid, and HV fluid from the pleural space of canine cadavers. Further study is necessary to determine if SB and LB thoracostomy tubes demonstrate similar efficacy in clinical veterinary patients. © Veterinary Emergency and Critical Care Society 2017.

  1. BORE II

    SciTech Connect

    2015-08-01

    Bore II, co-developed by Berkeley Lab researchers Frank Hale, Chin-Fu Tsang, and Christine Doughty, provides vital information for solving water quality and supply problems and for improving remediation of contaminated sites. Termed "hydrophysical logging," this technology is based on the concept of measuring repeated depth profiles of fluid electric conductivity in a borehole that is pumping. As fluid enters the wellbore, its distinct electric conductivity causes peaks in the conductivity log that grow and migrate upward with time. Analysis of the evolution of the peaks enables characterization of groundwater flow distribution more quickly, more cost effectively, and with higher resolution than ever before. Combining the unique interpretation software Bore II with advanced downhole instrumentation (the hydrophysical logging tool), the method quantifies inflow and outflow locations, their associated flow rates, and the basic water quality parameters of the associated formation waters (e.g., pH, oxidation-reduction potential, temperature). In addition, when applied in conjunction with downhole fluid sampling, Bore II makes possible a complete assessment of contaminant concentration within groundwater.

  2. 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

  3. 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.

  4. CONCEPTUAL DESIGN OF PION CAPTURE MAGNETS OF UP TO 15 CM BORE AND 20 T PEAK FIELD.

    SciTech Connect

    WEGGEL,R.J.

    2001-09-24

    For the Neutrino Factory and Muon Collider Collaboration, BNL has considered solenoidal magnet systems of several types to capture pions generated by bombarding a mercury jet with multi-GeV protons. The magnet systems generate up to 20 T, uniform to 5% throughout a cylindrical volume 0.15 m in diameter and 0.6 m long. Axially downstream the field ramps gradually downward by a factor of sixteen, while the bore increases fourfold. The steady-state system needed for an accelerator has many superconducting coils and a radiation-resistant insert of mineral-insulated hollow conductor. Less costly, pulsed systems suffice to study pion capture and the effect of a magnetic field on a jet hit by a proton beam. BNL has explored three types of magnets, each with its principal coils precooled by liquid nitrogen. One type employs two sets of coils energized sequentially. Charged in 23 s by a power supply of 5 MVA, the 16ton outer set generates 10 T and stores 28 MJ, from which, in 1/3 s, to charge a half-ton inner coil that adds 12 1/2 T to the 7 1/2 T remaining from the outer set. An alternative design uses 25 MVA to energize, in 1.4 s, a single 3-ton set of coils. The third type bows to budgetary constraints and is more modest in size and performance. A magnet of 2-3 tons generates 10-11 T with only 2 MVA, in a bore big enough (11 cm) to accommodate the jet. It forgoes the field ramp that improves pion retention.

  5. Minimally invasive versus conventional large-bore percutaneous nephrolithotomy in the treatment of large-sized renal calculi: Surgeon's preference?

    PubMed

    Abdelhafez, Mohamed F; Wendt-Nordahl, Gunnar; Kruck, Stefan; Mager, Rene; Stenzl, Arnulf; Knoll, Thomas; Schilling, David

    2016-06-01

    The aim of this study was to compare the efficacy and safety of minimally invasive percutaneous nephrolithotomy (MIP) and conventional percutaneous nephrolithotomy (PCNL) in the treatment of patients with large renal stone burden. MIP has proven its efficacy and safety in the management of small renal calculi. However, conventional PCNL is still considered the standard method for treatment of large renal stones in the upper urinary tract. A search of two longitudinal databases in two tertiary referral centres for complex stone disease identified 133 consecutive patients who were treated by either MIP or PCNL for renal stones 20 mm or larger between January 2009 and August 2012. Clinical data and outcome measures of the two methods were compared by Student's t test, chi-squared test or Fisher's exact test. A p value less than 0.05 was considered statistically significant. Operative time was significantly shorter and hospital stay was significantly longer in conventional PCNL compared to MIP (p = 0.002 and < 0.001, respectively). There were no significant differences in primary stone-free rate or complication rate between the two methods. Only higher graded complications (above Clavien grade II) were significantly more common in conventional PCNL (p = 0.02). MIP is equally effective as conventional PCNL in the treatment of large renal calculi. Both methods have a similar complication rate. The shorter operative time in PCNL may be based on the larger diameter and quicker retrieval of large fragments; the longer mean hospital stay may be caused by the handling of the nephrostomy tube. The current data suggest that the choice of the method mainly depends on the surgeon's preference.

  6. 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.

  7. Ultra-wide bore 900 MHz high-resolution NMR at the National High Magnetic Field Laboratory.

    PubMed

    Fu, R; Brey, W W; Shetty, K; Gor'kov, P; Saha, S; Long, J R; Grant, S C; Chekmenev, E Y; Hu, J; Gan, Z; Sharma, M; Zhang, F; Logan, T M; Brüschweller, R; Edison, A; Blue, A; Dixon, I R; Markiewicz, W D; Cross, T A

    2005-11-01

    Access to an ultra-wide bore (105 mm) 21.1 T magnet makes possible numerous advances in NMR spectroscopy and MR imaging, as well as novel applications. This magnet was developed, designed, manufactured and tested at the National High Magnetic Field Laboratory and on July 21, 2004 it was energized to 21.1 T. Commercial and unique homebuilt probes, along with a standard commercial NMR console have been installed and tested with many science applications to develop this spectrometer as a user facility. Solution NMR of membrane proteins with enhanced resolution, new pulse sequences for solid state NMR taking advantage of narrowed proton linewidths, and enhanced spatial resolution and contrast leading to improved animal imaging have been documented. In addition, it is demonstrated that spectroscopy of single site (17)O labeled macromolecules in a hydrated lipid bilayer environment can be recorded in a remarkably short period of time. (17)O spectra of aligned samples show the potential for using this data for orientational restraints and for characterizing unique details of cation binding properties to ion channels. The success of this NHMFL magnet illustrates the potential for using a similar magnet design as an outsert for high temperature superconducting insert coils to achieve an NMR magnet with a field >25 T.

  8. Ultra-wide bore 900 MHz high-resolution NMR at the National High Magnetic Field Laboratory

    NASA Astrophysics Data System (ADS)

    Fu, R.; Brey, W. W.; Shetty, K.; Gor'kov, P.; Saha, S.; Long, J. R.; Grant, S. C.; Chekmenev, E. Y.; Hu, J.; Gan, Z.; Sharma, M.; Zhang, F.; Logan, T. M.; Brüschweller, R.; Edison, A.; Blue, A.; Dixon, I. R.; Markiewicz, W. D.; Cross, T. A.

    2005-11-01

    Access to an ultra-wide bore (105 mm) 21.1 T magnet makes possible numerous advances in NMR spectroscopy and MR imaging, as well as novel applications. This magnet was developed, designed, manufactured and tested at the National High Magnetic Field Laboratory and on July 21, 2004 it was energized to 21.1 T. Commercial and unique homebuilt probes, along with a standard commercial NMR console have been installed and tested with many science applications to develop this spectrometer as a user facility. Solution NMR of membrane proteins with enhanced resolution, new pulse sequences for solid state NMR taking advantage of narrowed proton linewidths, and enhanced spatial resolution and contrast leading to improved animal imaging have been documented. In addition, it is demonstrated that spectroscopy of single site 17O labeled macromolecules in a hydrated lipid bilayer environment can be recorded in a remarkably short period of time. 17O spectra of aligned samples show the potential for using this data for orientational restraints and for characterizing unique details of cation binding properties to ion channels. The success of this NHMFL magnet illustrates the potential for using a similar magnet design as an outsert for high temperature superconducting insert coils to achieve an NMR magnet with a field >25 T.

  9. Excisional biopsy of borderline lesions after large bore vacuum-assisted core needle biopsy- is it necessary?

    PubMed

    Green, Sari; Khalkhali, Iraj; Azizollahi, Elliot; Venegas, Rose; Jalil, Yasmin; Dauphine, Christine

    2011-10-01

    The current recommendation for borderline breast lesions after core needle biopsy is for surgical excision due to a high rate of pathologic underestimation. With the use of vacuum-assisted core needle (VACN) biopsy devices, upgrade rates have improved, but still average 20 per cent. We routinely use larger bore VACNs (7- and 8-gauge) than previously reported (9 to 11-gauge). The aim of this study is to evaluate the upgrade rate to malignancy in patients undergoing VACN using larger bore needles. VACN biopsies were performed in 902 patients. Of those, 87 were recommended excisional biopsy for borderline or noncorrelating lesions and 66 underwent the procedure. Two patients were upgraded to cancer, for an overall upstage rate of 3 per cent. Both of these underestimations were in patients that initially had atypical ductal hyperplasia. In the patients not excised, no patient developed further cancer. A 7- or 8-gauge needle was used in 57 per cent of patients, greater than 90 per cent removal of the initial lesion was accomplished in 53 per cent of cases, and there were no bleeding complications. This study suggests that upgrade rates decline with larger bore biopsy needles with near complete excision of the initial lesion, and that some borderline lesions may potentially be managed nonoperatively.

  10. Twists and turns--How we stepped into and had fun in the "boring" lipid field.

    PubMed

    Han, Min

    2015-11-01

    Compared to proteins and RNAs, functional specificities associated with structural variations in fatty acids and lipids have been greatly underexplored. This review describes how our lab naively started to work on lipids 14 years ago, and how we have gradually overcome obstacles to address some interesting biological questions by combining genetics with biochemical methods on the nematode Caenorhabditis elegans. Our studies have revealed lipid variants and their metabolic pathways, in specific tissues, impact development and behaviors by regulating specific signaling events. The review also discusses the general research approach, style of lab management, and funding mechanisms that have facilitated the frequent research direction changes in the lab, including the journey into the lipid field.

  11. Inflating with large effective fields

    NASA Astrophysics Data System (ADS)

    Burgess, C. P.; Cicoli, M.; Quevedo, F.; Williams, M.

    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 propto phi2) and exponential potentials, V(phi) = ∑kVxe-kphi/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| ll epsilon and so predict r simeq (8/3)(1-ns) consequently ns simeq 0.96 gives r simeq 0.11 but not much larger (and so could be ruled out as measurements on r and ns 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.

  12. 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.

  13. 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.

  14. On bore collapse

    NASA Astrophysics Data System (ADS)

    Yeh, Harry H.; Ghazali, A.

    1988-06-01

    Using the laser-induced fluorescent method, the transition process from bore to runup mode, i.e., "bore collapse," is investigated experimentally. The observed process appears to be different from both previous analytical and numerical predictions. The results indicate that momentum exchange takes place between the incident bore and the quiescent water body along the shoreline. Turbulence generated in a bore nearshore is highly three-dimensional and sporadic. Very close to the shore, turbulence is advected with the bore front, and consequently, the bore collapse process involves strong turbulent action onto the dry beach bed.

  15. MRI-guided core biopsy of the prostate in the supine position--introduction of a simplified technique using large-bore magnet systems.

    PubMed

    Schwab, Siegfried A; Kuefner, Michael A; Adamietz, Boris; Engelhard, Karl; Keck, Bastian; Kunath, Frank; Wach, Sven; Wullich, Bernd; Uder, Michael; Engehausen, Dirk G

    2013-05-01

    To introduce a simplified technique for MRI-guided core biopsies (MRGB) of the prostate in the supine position using large-bore magnet systems. Fifty men with a history of negative transrectal ultrasound-guided biopsies underwent MRGB in either a 1.5-T (13/50) or 3.0-T (37/50) wide-bore MRI unit. MRGBs were conducted with the patients in a supine position using a dedicated MR-compatible biopsy device. We developed a dedicated positioning device for the supine position. Using this device, the biopsies were performed successfully in all patients. Apart from minor rectal bleeding, only one patient developed a major side effect (urosepsis). Histology revealed prostate cancer in 25/50 (50 %) patients. The new technique appears feasible. Its major advantage is the more comfortable and patient-friendly supine position during the biopsy without the need to modify the MRI system's patient table. • A novel positioning device for MRI-guided prostate biopsies has been developed. • Biopsies can be performed in the patient-friendly supine position. • The positioning device can be utilised without modifying the MRI's patient table.

  16. 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.

  17. Percutaneous Management of Accidentally Retained Foreign Bodies During Image-Guided Non-vascular Procedures: Novel Technique Using a Large-Bore Biopsy System.

    PubMed

    Cazzato, Roberto Luigi; Garnon, Julien; Ramamurthy, Nitin; Tsoumakidou, Georgia; Caudrelier, Jean; Thénint, Marie-Aude; Rao, Pramod; Koch, Guillaume; Gangi, Afshin

    2016-07-01

    To describe a novel percutaneous image-guided technique using a large-bore biopsy system to retrieve foreign bodies (FBs) accidentally retained during non-vascular interventional procedures. Between May 2013 and October 2015, five patients underwent percutaneous retrieval of five iatrogenic FBs, including a biopsy needle tip in the femoral head following osteoblastoma biopsy and radiofrequency ablation (RFA); a co-axial needle shaft within a giant desmoid tumour following cryoablation; and three post-vertebroplasty cement tails within paraspinal muscles. All FBs were retrieved immediately following original procedures under local or general anaesthesia, using combined computed tomography (CT) and fluoroscopic guidance. The basic technique involved positioning a 6G trocar sleeve around the FB long axis and co-axially advancing an 8G biopsy needle to retrieve the FB within the biopsy core. Retrospective chart review facilitated analysis of procedures, FBs, technical success, and complications. Mean FB size was 23 mm (range 8-74 mm). Four FBs were located within 10 mm of non-vascular significant anatomic structures. The basic technique was successful in 3 cases; 2 cases required technical modifications including using a stiff guide-wire to facilitate retrieval in the case of the post-cryoablation FB; and using the central mandrin of the 6G trocar to push a cement tract back into an augmented vertebra when initial retrieval failed. Overall technical success (FB retrieval or removal to non-hazardous location) was 100 %, with no complications. Percutaneous image-guided retrieval of iatrogenic FBs using a large-bore biopsy system is a feasible, safe, effective, and versatile technique, with potential advantages over existing methods.

  18. Current-day employment of the micro-bore open-tubular capillary column in the gas chromatography field.

    PubMed

    Tranchida, Peter Quinto; Mondello, Luigi

    2012-10-26

    The present contribution is focused on the exploitation of the micro-bore (MB) open-tubular column (ID≤0.18 mm), in current-day gas chromatography. The vast majority of GC methods involve the use of MB columns, from a variety of one-dimensional techniques (conventional and high speed), to different forms of heart-cutting and comprehensive multidimensional methodologies. Various aspects related to the use of MB open-tubular capillaries will be described and critically discussed, along with a series of pertinent applications. A series of works from the past have also been cited, essentially because many approaches today-applied, derive from the ideas of the past. Obviously, the present contribution does not review the entire history of the micro-bore capillary (more than one book would be necessary); rather, it intends to portray the great contribution that such analytical tools provide in enhancing two fundamental GC features, namely separation power and speed. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Guided earth boring tool

    SciTech Connect

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

    1987-09-22

    A controllable tool for drilling holes in the earth is described comprising a hollow elongated rigid supporting drill pipe having a forward end for entering the earth, means supporting the drill pipe for earth boring or piercing movement, including means for moving the drill pipe longitudinally for penetrating the earth, the drill pipe moving means being constructed to permit addition and removal of supporting drill pipe during earth penetrating operation, a boring mole supported on the forward end of the hollow low drill pipe comprising a cylindrical housing supported on and open to the forward end of the drill pipe, a first means on the front end for applying a boring force to the soil comprising an anvil having a striking surface inside the housing and a boring surface outside the housing, a second means comprising a reciprocally movable hammer positioned in the housing to apply a percussive force to the anvil striking surface for transmitting a percussive force to the boring force applying means, and means permitting introduction of air pressure supplied through the hollow pipe into the housing for operating the hammer and for discharging spent air from the housing to the hole being bored, and the tool being operable to penetrate the earth upon longitudinal movement of the drill rod by the longitudinal rod moving means and operation of the mole by reciprocal movement of the hammer.

  7. An ultra-high field strength MR image-guided robotic needle delivery system for in-bore small animal interventions.

    PubMed

    Gravett, Matthew; Cepek, Jeremy; Fenster, Aaron

    2017-08-28

    The purpose of this study was to develop and validate an image-guided robotic needle delivery system for accurate and repeatable needle targeting procedures in mouse brains inside the 12 cm inner diameter gradient coil insert of a 9.4 T MR scanner. Many preclinical research techniques require the use of accurate needle deliveries to soft tissues, including brain tissue. Soft tissues are optimally visualized in MR images, which offer high-soft tissue contrast, as well as a range of unique imaging techniques, including functional, spectroscopy and thermal imaging, however, there are currently no solutions for delivering needles to small animal brains inside the bore of an ultra-high field MR scanner. This paper describes the mechatronic design, evaluation of MR compatibility, registration technique, mechanical calibration, the quantitative validation of the in-bore image-guided needle targeting accuracy and repeatability, and demonstrated the system's ability to deliver needles in situ. Our six degree-of-freedom, MR compatible, mechatronic system was designed to fit inside the bore of a 9.4 T MR scanner and is actuated using a combination of piezoelectric and hydraulic mechanisms. The MR compatibility and targeting accuracy of the needle delivery system are evaluated to ensure that the system is precisely calibrated to perform the needle targeting procedures. A semi-automated image registration is performed to link the robot coordinates to the MR coordinate system. Soft tissue targets can be accurately localized in MR images, followed by automatic alignment of the needle trajectory to the target. Intra-procedure visualization of the needle target location and the needle were confirmed through MR images after needle insertion. The effects of geometric distortions and signal noise were found to be below threshold that would have an impact on the accuracy of the system. The system was found to have negligible effect on the MR image signal noise and geometric distortion

  8. Optimization of a novel large field of view distortion phantom for MR-only treatment planning

    PubMed Central

    Price, Ryan G.; Knight, Robert A.; Hwang, Ken-Pin; Bayram, Ersin; Nejad-Davarani, Siamak P.; Glide-Hurst, Carri K.

    2017-01-01

    Purpose MR-only treatment planning requires images of high geometric fidelity, particularly for large fields of view (FOV). However, the availability of large FOV distortion phantoms with analysis software is currently limited. This work sought to optimize a modular distortion phantom to accommodate multiple bore configurations and implement distortion characterization in a widely implementable solution. Method and Materials To determine candidate materials, 1.0 T MR and CT images were acquired of twelve urethane foam samples of various densities and strengths. Samples were precision-machined to accommodate 6 mm diameter paintballs used as landmarks. Final material candidates were selected by balancing strength, machinability, weight, and cost. Bore sizes and minimum aperture width resulting from couch position were tabulated from the literature (14 systems, 5 vendors). Bore geometry and couch position were simulated using MATLAB to generate machine-specific models to optimize the phantom build. Previously developed software for distortion characterization was modified for several magnet geometries (1.0 T, 1.5 T, 3.0 T), compared against previously published 1.0 T results, and integrated into the 3D Slicer application platform. Results All foam samples provided sufficient MR image contrast with paintball landmarks. Urethane foam (compressive strength ~1000 psi, density ~20 lb/ft3) was selected for its accurate machinability and weight characteristics. For smaller bores, a phantom version with the following parameters was used: 15 foam plates, 55 × 55 × 37.5 cm3 (L×W×H), 5,082 landmarks, and weight ~30 kg. To accommodate > 70 cm wide bores, an extended build used 20 plates spanning 55 × 55 × 50 cm3 with 7,497 landmarks and weight ~44 kg. Distortion characterization software was implemented as an external module into 3D Slicer’s plugin framework and results agreed with the literature. Conclusion The design and implementation of a modular, extendable

  9. Optimization of a novel large field of view distortion phantom for MR-only treatment planning.

    PubMed

    Price, Ryan G; Knight, Robert A; Hwang, Ken-Pin; Bayram, Ersin; Nejad-Davarani, Siamak P; Glide-Hurst, Carri K

    2017-07-01

    MR-only treatment planning requires images of high geometric fidelity, particularly for large fields of view (FOV). However, the availability of large FOV distortion phantoms with analysis software is currently limited. This work sought to optimize a modular distortion phantom to accommodate multiple bore configurations and implement distortion characterization in a widely implementable solution. To determine candidate materials, 1.0 T MR and CT images were acquired of twelve urethane foam samples of various densities and strengths. Samples were precision-machined to accommodate 6 mm diameter paintballs used as landmarks. Final material candidates were selected by balancing strength, machinability, weight, and cost. Bore sizes and minimum aperture width resulting from couch position were tabulated from the literature (14 systems, 5 vendors). Bore geometry and couch position were simulated using MATLAB to generate machine-specific models to optimize the phantom build. Previously developed software for distortion characterization was modified for several magnet geometries (1.0 T, 1.5 T, 3.0 T), compared against previously published 1.0 T results, and integrated into the 3D Slicer application platform. All foam samples provided sufficient MR image contrast with paintball landmarks. Urethane foam (compressive strength ∼1000 psi, density ~20 lb/ft(3) ) was selected for its accurate machinability and weight characteristics. For smaller bores, a phantom version with the following parameters was used: 15 foam plates, 55 × 55 × 37.5 cm(3) (L×W×H), 5,082 landmarks, and weight ~30 kg. To accommodate > 70 cm wide bores, an extended build used 20 plates spanning 55 × 55 × 50 cm(3) with 7,497 landmarks and weight ~44 kg. Distortion characterization software was implemented as an external module into 3D Slicer's plugin framework and results agreed with the literature. The design and implementation of a modular, extendable distortion phantom was optimized for several bore

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. Improved Large-Field Focusing Schlieren System

    NASA Technical Reports Server (NTRS)

    Weinstein, Leonard M.

    1993-01-01

    System used to examine complicated two- and three-dimensional flows. High-brightness large-field focusing schlieren system incorporates Fresnel lens instead of glass diffuser. In system with large field of view, image may also be very large. Relay optical subsystem minifies large image while retaining all of light. Facilities candidates for use of focusing schlieren include low-speed wind and water tunnels. Heated or cooled flow tracers or injected low- or high-density tracers used to make flows visible for photographic recording.

  15. Ultrasonic Inspection Near Small Bores

    NASA Technical Reports Server (NTRS)

    Parent, R. G.

    1986-01-01

    Portable ultrasonic probe makes it possible to inspect for hidden cracks near insides of narrow tubes. Using pulse-echo technique, instrument detects cracks as small as 0.015-in. (0.38-mm) deep. Used for nondestructive inspection of other hard-to-reach places where conventional large transducers will not fit or where difficult to apply coupling liquid for contact ultrasonic testing. Inspects bore of tubelike fitting. Instrument makes it unnecessary to disassemble fitting to check for cracks. Precise orientation of transducer with respect to part not necessary for detecting cracks.

  16. Detecting Microbially Induced Calcite Precipitation in a Model Well-Bore Using Downhole Low-Field NMR

    DOE PAGES

    Kirkland, Catherine M.; Zanetti, Sam; Grunewald, Elliot; ...

    2016-12-20

    Microbially induced calcite precipitation (MICP) has been widely researched recently due to its relevance for subsurface engineering applications including sealing leakage pathways and permeability modification. These applications of MICP are inherently difficult to monitor nondestructively in time and space. Nuclear magnetic resonance (NMR) can characterize the pore size distributions, porosity, and permeability of subsurface formations. This investigation used a low-field NMR well-logging probe to monitor MICP in a sand-filled bioreactor, measuring NMR signal amplitude and T2 relaxation over an 8 day experimental period. Following inoculation with the ureolytic bacteria, Sporosarcina pasteurii, and pulsed injections of urea and calcium substrate, themore » NMR measured water content in the reactor decreased to 76% of its initial value. T2 relaxation distributions bifurcated from a single mode centered about approximately 650 ms into a fast decaying population (T2 less than 10 ms) and a larger population with T2 greater than 1000 ms. The combination of changes in pore volume and surface minerology accounts for the changes in the T2 distributions. Destructive sampling confirmed final porosity was approximately 88% of the original value. Here, these results indicate the low-field NMR well-logging probe is sensitive to the physical and chemical changes caused by MICP in a laboratory bioreactor.« less

  17. Detecting Microbially Induced Calcite Precipitation in a Model Well-Bore Using Downhole Low-Field NMR

    SciTech Connect

    Kirkland, Catherine M.; Zanetti, Sam; Grunewald, Elliot; Walsh, David O.; Codd, Sarah L.; Phillips, Adrienne J.

    2016-12-20

    Microbially induced calcite precipitation (MICP) has been widely researched recently due to its relevance for subsurface engineering applications including sealing leakage pathways and permeability modification. These applications of MICP are inherently difficult to monitor nondestructively in time and space. Nuclear magnetic resonance (NMR) can characterize the pore size distributions, porosity, and permeability of subsurface formations. This investigation used a low-field NMR well-logging probe to monitor MICP in a sand-filled bioreactor, measuring NMR signal amplitude and T2 relaxation over an 8 day experimental period. Following inoculation with the ureolytic bacteria, Sporosarcina pasteurii, and pulsed injections of urea and calcium substrate, the NMR measured water content in the reactor decreased to 76% of its initial value. T2 relaxation distributions bifurcated from a single mode centered about approximately 650 ms into a fast decaying population (T2 less than 10 ms) and a larger population with T2 greater than 1000 ms. The combination of changes in pore volume and surface minerology accounts for the changes in the T2 distributions. Destructive sampling confirmed final porosity was approximately 88% of the original value. Here, these results indicate the low-field NMR well-logging probe is sensitive to the physical and chemical changes caused by MICP in a laboratory bioreactor.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. Why are some microorganisms boring?

    PubMed

    Cockell, Charles S; Herrera, Aude

    2008-03-01

    Microorganisms from diverse environments actively bore into rocks, contributing significantly to rock weathering. Carbonates are the most common substrate into which they bore, although there are also reports of microbial borings into volcanic glass. One of the most intriguing questions in microbial evolutionary biology is why some microorganisms bore. A variety of possible selection pressures, including nutrient acquisition, protection from UV radiation and predatory grazing could promote boring. None of these pressures is mutually exclusive and many of them could have acted in concert with varying strengths in different environments to favour the development of microorganisms that bore. We suggest that microbial boring might have begun in some environments as a mechanism against entombment by mineralization.

  3. 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.

  4. 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.

  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. 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.

  7. Performance of large-bore tapered-roller bearings under combined radial and thrust load at shaft speeds to 15,000 rpm

    NASA Technical Reports Server (NTRS)

    Parker, R. J.; Signer, H. R.

    1977-01-01

    The performance of 120.65-mm bore tapered roller bearings was investigated at shaft speeds up to 15,000 rpm. Temperature distribution and bearing heat generation were determined as a function of shaft speed, radial and thrust loads, lubricant flow rate, and lubricant inlet temperature. Lubricant was supplied by either jets or by a combination of holes through the cone directly to the cone-rib contact and jets at the roller small-end side. Cone-rib lubrication significantly improved high-speed tapered-roller bearing performance, yielding lower cone-face temperatures and lower power loss and allowing lower lubricant flow rates for a given speed condition. Bearing temperatures increased with increased shaft speed and decreased with increased lubricant flow rate. Bearing power loss increased with increased shaft speed and increased lubricant flow rate.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. Numerical modeling of mesospheric bores

    NASA Astrophysics Data System (ADS)

    Laughman, Brian Joseph

    Mesospheric bores were first observed in 1993 and since then there have been few efforts to characterize them. Early results invoked weakly nonlinear hydraulic theory to explain these observed bores and numerical results have reproduced the essential nonlinearities of bore evolution. Internal bores have been demonstrated to exist in density stratified fluids, such as the oceanic thermocline and tropospheric inversion layers, and have been approximated by the Benjamin-Davis-Ono (BDO) equation (the KdV analogue for internal waves). This thesis considers these earlier theories and explores the limits of their validity with two numerical models. The first is a one-dimensional solver of the KdV and BDO equations. The second model describes the nonlinear incompressible dynamics of the Navier-Stokes equations for thermal ducting environments. The results of both models are directly compared to constrain the validity of the weakly nonlinear theory. These results are also compared with spatial and velocity scales of airglow observations and demonstrate the viability of simple mesopausal thermal ducting environments to support realistic bore evolution. Based on observations and on the dependence of the dispersion relationship on the mean horizontal wind, Doppler ducting structures are posed and also demonstrate nonlinear bore evolution. The direction of future studies is then discussed, including extensions to more complex and realistic ducting environments characteristic of the mesosphere and lower thermosphere (MLT), the viability of forcing mechanisms beyond the long wave perturbations considered in these studies, and applications to observed bore events.

  17. 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.

  18. Monte Carlo simulation of large electron fields

    PubMed Central

    Faddegon, Bruce A; Perl, Joseph; Asai, Makoto

    2010-01-01

    Two Monte Carlo systems, EGSnrc and Geant4, the latter with two different “physics lists,” were used to calculate dose distributions in large electron fields used in radiotherapy. Source and geometry parameters were adjusted to match calculated results to measurement. Both codes were capable of accurately reproducing the measured dose distributions of the 6 electron beams available on the accelerator. Depth penetration matched the average measured with a diode and parallel-plate chamber to 0.04 cm or better. Calculated depth dose curves agreed to 2% with diode measurements in the buildup region, although for the lower beam energies there was a discrepancy of up to 5% in this region when calculated results are compared to parallel-plate measurements. Dose profiles at the depth of maximum dose matched to 2-3% in the central 25 cm of the field, corresponding to the field size of the largest applicator. A 4% match was obtained outside the central region. The discrepancy observed in the bremsstrahlung tail in published results that used EGS4 is no longer evident. Simulations with the different codes and physics lists used different source energies, incident beam angles, thicknesses of the primary foils, and distance between the primary and secondary foil. The true source and geometry parameters were not known with sufficient accuracy to determine which parameter set, including the energy of the source, was closest to the truth. These results underscore the requirement for experimental benchmarks of depth penetration and electron scatter for beam energies and foils relevant to radiotherapy. PMID:18296775

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Turbulent Bore Wave Propagation on a Linear Sloping Beach

    NASA Astrophysics Data System (ADS)

    Weiss, J. M.; Piccirillo, P. B.; Tremain, D. E.; Orwoll, M.; Abdou, I.

    2002-12-01

    Turbulent bore waves formed after wave breaking on beaches have been studied in the field with natural incident waves and in laboratory wave tanks for monochromatic incident wave spectra. The present research attempts to extend previous results both by focussing on broadband incident wave spectra and by looking carefully at the evolution of the turbulent bores in a highly instrumented wave tank. In our current research, turbulent bores are generated in the Max Hammond Wave Tank at SRI with a 1:25 sloped linear beach by two types of incident spectra: a monochromatic sine wave spectrum for repeatable experiments and a JONSWAP spectra (gamma=3.3) for more realistic incident waves. Instrumentation employed for measurement of bore propagation includes: 20 capacitive wave height gauges, a Ku-band Doppler radar and simultaneous video recording. There is also both a surface PIV and volume PIV capability for reconstructing fluid flow in the bore wave volume and on the surface but these measurements are not included in the experiments reported here. We have also developed a wavefront tracking algorithm that retrieves bore propagation velocity from the video imagery as a function of position. In this paper, we present measurements of the phase speed of bore waves as a function of bottom depth for a range of wave breaker types from gentle spillers to violent plungers for both monochromatic and JONSWAP broadband incident spectra. Our results are compared with shallow-water Boussinesq model predictions. The goals of this research are to improve prediction of turbulent bore waves in realistic conditions and develop remote sensing techniques for retrieving bathymetry and other surf-zone properties of the nearshore environment.

  4. 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.

  5. 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.

  6. 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.

  7. Can tasks be inherently boring?

    PubMed

    Charney, Evan

    2013-12-01

    Kurzban et al. argue that the experiences of "effort," "boredom," and "fatigue" are indications that the costs of a task outweigh its benefits. Reducing the costs of tasks to "opportunity costs" has the effect of rendering tasks costless and of denying that they can be inherently boring or tedious, something that "vigilance tasks" were intentionally designed to be.

  8. Fast magnetic reconnection with large guide fields

    SciTech Connect

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

    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 independent of the DR physics and is in good agreement with kinetic results.

  9. 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

  10. Discussion boards: boring no more!

    PubMed

    Adelman, Deborah S; Nogueras, Debra J

    2013-01-01

    Creating discussion boards (DBs) that capture student imaginations and contain meaningful interactions can be a difficult process. Traditional DBs use a question-and-answer format that often is boring for both the student and instructor. The authors present creative approaches to DBs that result in lively debates and student-to-student and student-to-faculty interactions, including role playing, blogging, wikis, and the use of voice.

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. Quality biotissue boring by transparent tips

    NASA Astrophysics Data System (ADS)

    Alejnikov, Vladislav S.; Armichev, A. V.; Masychev, Victor I.

    1992-08-01

    We considered the boring soft biotissues with laser-energized fibers for the two-step photodynamic therapy of deep-seated tumors. The proposed method and the corresponding equipment included the dye laser pumped by copper vapor laser have been discussed. Experiments were performed with potato tissues fixing heat penetration depths. It was established that a quality of resulted bore walls (the small coagulation depth and the absence of carbon deposits) is determined by laser powers, boring speeds, and properties of tissues.

  16. Boring deep holes in southern pine

    Treesearch

    G. E. Woodson; C. W. McMillin

    1972-01-01

    When holes 10-1/2 inches deep and I inch in diameter were made with either a ship auger or a double-spur, double-twist machine bit, clogging occurred at a shallower depth (avg. 6.5 inches) when boring across the grain than when boring along the grain (avg. 10.1 inches). In both boring directions, thrust force and torque demand for unclogged bits were less for the ship...

  17. TMI-2 core bore acquisition summary report

    SciTech Connect

    Tolman, E.L.; Smith, R.P.; Martin, M.R.; McCardell, R.K.; Broughton, J.M.

    1987-02-01

    Core bore samples were obtained from the severely damaged TMI-2 core during July and August, 1986. A description of the TMI-2 core bore drilling unit used to obtain samples; a summary and discussion of the data from the ten core bore segments which were obtained; and the initial results of analysis and evaluation of these data are presented in this report. The impact of the major findings relative to our understanding of the accident scenario is also discussed.

  18. 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.

  19. 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.

  20. 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.

  1. 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)

  2. 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)

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Amplification of large-scale magnetic field in nonhelical magnetohydrodynamics

    NASA Astrophysics Data System (ADS)

    Kumar, Rohit; Verma, Mahendra K.

    2017-09-01

    It is typically assumed that the kinetic and magnetic helicities play a crucial role in the growth of large-scale dynamo. In this paper, we demonstrate that helicity is not essential for the amplification of large-scale magnetic field. For this purpose, we perform nonhelical magnetohydrodynamic (MHD) simulation, and show that the large-scale magnetic field can grow in nonhelical MHD when random external forcing is employed at scale 1/10 the box size. The energy fluxes and shell-to-shell transfer rates computed using the numerical data show that the large-scale magnetic energy grows due to the energy transfers from the velocity field at the forcing scales.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Predicted sedimentary record of reflected bores

    USGS Publications Warehouse

    Higman, B.; Gelfenbaum, G.; Lynett, P.; Moore, A.; Jaffe, B.

    2007-01-01

    Where a steep slope blocks an inrushing tsunami, the tsunami commonly reverses direction as a reflected bore. A simple method for relating vertical and horizontal variation in sediment size to output from numerical models of depth-averaged tsunami flow yields predictions about the sedimentary record of reflected bores: 1. Near the reflector, a abrupt slowing of the flow as the reflected bore passes is recorded by a normally graded layer that drapes preexisting topography. 2. At intermediate distances from the reflector, the deposit consists of a single normally graded bed deposited preferentially in depressions, possibly including a sharp fine-over-coarse contact. This contact records a brief period of erosion as the front of the reflected bore passes. 3. Far seaward of the reflector, grading in the deposit includes two distinct normally graded beds deposited preferentially in depressions separated by an erosional unconformity. The second normally graded bed records the reflected bore.

  14. 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.

  15. 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

  16. Analysis of surface moisture variations within large field sites

    NASA Technical Reports Server (NTRS)

    Bell, K. R.; Blanchard, B. J.; Witczak, M. W.; Schmugge, T. J.

    1979-01-01

    A statistical analysis was made on ground soils to define the general relationship and ranges of values of the field moisture relative to both the variance and coefficient of variation for a given test site and depth increment. The results of the variability study show that: (1) moisture variations within any given large field area are inherent and can either be controlled nor reduced; (2) neither a single value of the standard deviation nor coefficient of variation uniquely define the variability over the complete range of mean field moisture contents examined; and (3) using an upper bound standard deviation parameter clearly defines the maximum range of anticipated moisture variability. 87 percent of all large field moisture content standard deviations were less than 3 percent while about 96 percent of all the computed values had an upper bound of sigma=4 percent for these intensively sampled fields. The limit of accuracy curves of mean soil moisture measurements for large field sites relative to the required number of samples were determined.

  17. 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.

  18. 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.

  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. 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.

  1. 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.

  2. Scalable Parallel Distance Field Construction for Large-Scale Applications.

    PubMed

    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. A new distributed spatial data structure, named parallel distance tree, is introduced to manage the level sets of data and facilitate surface tracking over time, 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. Our work greatly extends the usability of distance fields for demanding applications.

  3. 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.

  4. A note on large gauge transformations in double field theory

    DOE PAGES

    Naseer, Usman

    2015-06-01

    We give a detailed proof of the conjecture by Hohm and Zwiebach in double field theory. This result implies that their proposal for large gauge transformations in terms of the Jacobian matrix for coordinate transformations is, as required, equivalent to the standard exponential map associated with the generalized Lie derivative along a suitable parameter.

  5. Large-scale solar magnetic field mapping: I.

    PubMed

    Schatten, Kenneth H

    2013-12-01

    This article focuses on mapping the Sun's large-scale magnetic fields. In particular, the model considers how photospheric fields evolve in time. Our solar field mapping method uses Netlogo's cellular automata software via algorithms to carry out the movement of magnetic field on the Sun via agents. This model's entities consist of two breeds: blue and red agents. The former carry a fixed amount of radially outward magnetic flux: 10(23) Mx, and the latter, the identical amount of inward directed flux. The individual agents are distinguished, for clarity, by various shades of blue and red arrows whose orientation indicates the direction the agents are moving, relative to the near-steady bulk fluid motions. The fluid motions generally advect the field with the well known meridional circulation and differential rotation. Our model predominantly focuses on spatial and temporal variations from the bulk fluid motions owing to magnetic interactions. There are but a few effects that agents have on each other: i) while at the poles, field agents are connected via the Babcock - Leighton (B - L) subsurface field to other latitudes. This allows them to undertake two duties there: A) the B - L subsurface field spawns the next generation of new magnetic field via new agents, and B) the B - L subsurface field attracts lower-latitude fields via the "long-range" magnetic stress tension; ii) nearby agents affect each other's motion by short-range interactions; and iii) through annihilation: when opposite field agents get too close to each other, they disappear in pairs. The behavior of the agents' long- and short-range magnetic forces is discussed within this paper as well as the model's use of internal boundary conditions. The workings of the model may be seen in the accompanying movies and/or by using the software available via SpringerPlus' website, or on the Netlogo (TM) community website, where help is readable available, and should all these fail, some help from the author.

  6. Post-grouting bored pile technology

    NASA Astrophysics Data System (ADS)

    Zheng, A. R.

    2017-04-01

    Post-grouting is an effective technology to modify the shortcomings of thick bottom slime and shaft mudcake for the slurry bored pile. Construction procedure, parameter selection and strengthening mechanism of post-grouting bored pile had been introduced in this paper. Development of study on physical and mechanical properties of surrounding soil post-grouted was summarized. The bearing capacity behaviour and deformation properties of the pile were also analyzed. It will provide some advice for the research and application of post-grouting bored pile.

  7. The large-scale properties of simulated cosmological magnetic fields

    NASA Astrophysics Data System (ADS)

    Marinacci, Federico; Vogelsberger, Mark; Mocz, Philip; Pakmor, Rüdiger

    2015-11-01

    We perform uniformly sampled large-scale cosmological simulations including magnetic fields with the moving mesh code AREPO. We run two sets of MHD simulations: one including adiabatic gas physics only; the other featuring the fiducial feedback model of the Illustris simulation. In the adiabatic case, the magnetic field amplification follows the B ∝ ρ2/3 scaling derived from `flux-freezing' arguments, with the seed field strength providing an overall normalization factor. At high baryon overdensities the amplification is enhanced by shear flows and turbulence. Feedback physics and the inclusion of radiative cooling change this picture dramatically. In haloes, gas collapses to much larger densities and the magnetic field is amplified strongly and to the same maximum intensity irrespective of the initial seed field of which any memory is lost. At lower densities a dependence on the seed field strength and orientation, which in principle can be used to constrain models of cosmic magnetogenesis, is still present. Inside the most massive haloes magnetic fields reach values of ˜ 10-100 μG, in agreement with galaxy cluster observations. The topology of the field is tangled and gives rise to rotation measure signals in reasonable agreement with the observations. However, the rotation measure signal declines too rapidly towards larger radii as compared to observational data.

  8. Large field-of-view configurations for large-telescope adaptive optics systems: advantages and tradeoffs

    NASA Astrophysics Data System (ADS)

    Zhang, Xianyu; Herbst, Thomas M.; Rao, Changhui; Bizenberger, Peter; Conrad, Albert R.; Arcidiacono, Carmelo; Gaessler, Wolfgang; Ragazzoni, Roberto; Bertram, Thomas

    2012-09-01

    In order to achieve high sky coverage with natural guide star adaptive optics systems, the reference stars need to be chosen over a large field of view. But the size of the optical beam can become unmanageably large in current and planned future giant telescopes. This can render the optics unaffordable. To solve this issue, we have adopted two approaches - multiple fields of view and star-enlargers - for the LINC-NIRVANA layer-oriented, multiple-conjugated adaptive optics system. In this paper, we compare and contrast the advantages and disadvantages of various optical configurations for wide-field, natural guide star acquisition on current 8-meter and future 25-40 meter extremely large telescopes.

  9. 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).

  10. 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.

  11. Osedax borings in fossil marine bird bones

    PubMed Central

    Kahl, Wolf-Achim; Goedert, James L.

    2010-01-01

    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. PMID:21103978

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Traps and attractants for wood-boring insects in ponderosa pine stands in the Black Hills, South Dakota

    Treesearch

    Sheryl L. Costello; Jose F. Negron; William R. Jacobi

    2008-01-01

    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...

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Downhole temperature tool accurately measures well bore profile

    SciTech Connect

    Cloud, W.B. )

    1992-07-20

    This paper reports that an inexpensive temperature tool provides accurate temperatures measurements during drilling operations for better design of cement jobs, workovers, well stimulation, and well bore hydraulics. Valid temperature data during specific wellbore operations can improve initial job design, fluid testing, and slurry placement, ultimately enhancing well bore performance. This improvement applies to cement slurries, breaker activation for slurries, breaker activation for stimulation and profile control, and fluid rheological properties for all downhole operations. The temperature tool has been run standalone mounted inside drill pipe, on slick wire line and braided cable, and as a free-falltool. It has also been run piggyback on both directional surveys (slick line and free-fall) and standard logging runs. This temperature measuring system has been used extensively in field well bores to depths of 20,000 ft. The temperature tool is completely reusable in the field, ever similar to the standard directional survey tools used on may drilling rigs. The system includes a small, rugged, programmable temperature sensor, a standard body housing, various adapters for specific applications, and a personal computer (PC) interface.

  4. 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.

  5. Large scale meteorological influence during the Geysers 1979 field experiment

    SciTech Connect

    Barr, S.

    1980-01-01

    A series of meteorological field measurements conducted during July 1979 near Cobb Mountain in Northern California reveals evidence of several scales of atmospheric circulation consistent with the climatic pattern of the area. The scales of influence are reflected in the structure of wind and temperature in vertically stratified layers at a given observation site. Large scale synoptic gradient flow dominates the wind field above about twice the height of the topographic ridge. Below that there is a mixture of effects with evidence of a diurnal sea breeze influence and a sublayer of katabatic winds. The July observations demonstrate that weak migratory circulations in the large scale synoptic meteorological pattern have a significant influence on the day-to-day gradient winds and must be accounted for in planning meteorological programs including tracer experiments.

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

    NASA Technical Reports Server (NTRS)

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

    1973-01-01

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

  7. 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.

  8. 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; Lin, Yong; Martin, Sara F.; Panasenco, Olga; Romashets, Eugene P.

    2013-08-01

    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 serve 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 number and positions of the subfields are calculated automatically and represented by an array of bright points in the guider image which indicates the subfield centers inside the drawn rectangle of the total field on the computer screen with the whole-sun image. Automatic production of flats is also programmed. For the first time, mosaic movies were programmed from stored information on automated telescope motions. The mosaic movies show larger regions of the solar disk in high resolution and fill a gap between available whole-sun images with limited spatial resolution of synoptic telescopes including space instruments and small-field high-cadence movies of high-resolution solar telescopes.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Large field-of-view telescope for deep surveys

    NASA Astrophysics Data System (ADS)

    Barbe, Jacques P.; Cerutti-Maori, Guy; Rozelot, Jean-Pierre

    1997-03-01

    Conventional astronomical telescope makes use of a Ritchey- Chretien 2-mirror telescope, with a limited FOV except in the case of use of complex field corrector inducing spectral range limitations. For the future, large imaging telescope could offer main scientific advantages, like: (1) obtain a 3D description of the content of a large volume of the universe; (2) galaxy content and morphology; (3) galaxy red shift; (4) dark matter distribution; (5) absolute length scale. The present paper proposes for this large imaging telescope mission, the use of a Korsh, 3-mirror telescope thats characteristics are: (1) size approximately equals 2.5 meter; (2) field is greater than or equal to 1.5 degrees (but with no light on the optical axis); (3) image quality is less than or equal to 0.3 feet; (4) multispectral capabilities: from 0.35 micrometer up to 2.5 micrometer and more if needed; (5) real exit pupil with flat mirror; (6) good focal plane accessibility allowing multiple instrumentations: turret rotation of the previous flat mirror can be used, with several fixed instruments.

  2. 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.

  3. 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.

  4. 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.

  5. KENNEDY SPACE CENTER, FLA. - A female Red-bellied Woodpecker clings to a utility pole where it has made a home on Merritt Island Wildlife Refuge. The most common type of woodpecker in the South, the "Zebraback" nests in the cavities of trees and consumes large quantities of wood-boring beetles, as well as other insect pests. More than 280 species of birds make their homes on the 140,000-acre refuge, which lies within the boundaries of Kennedy Space Center.

    NASA Image and Video Library

    1995-04-10

    KENNEDY SPACE CENTER, FLA. - A female Red-bellied Woodpecker clings to a utility pole where it has made a home on Merritt Island Wildlife Refuge. The most common type of woodpecker in the South, the "Zebraback" nests in the cavities of trees and consumes large quantities of wood-boring beetles, as well as other insect pests. More than 280 species of birds make their homes on the 140,000-acre refuge, which lies within the boundaries of Kennedy Space Center.

  6. 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.

  7. Large Spin Perturbation Theory for Conformal Field Theories

    NASA Astrophysics Data System (ADS)

    Alday, Luis F.

    2017-09-01

    We consider conformal field theories around points of large twist degeneracy. Examples of this are theories with weakly broken higher spin symmetry and perturbations around generalized free fields. At the degenerate point we introduce twist conformal blocks. These are eigenfunctions of certain quartic operators and encode the contribution, to a given four-point correlator, of the whole tower of intermediate operators with a given twist. As we perturb around the degenerate point, the twist degeneracy is lifted. In many situations this breaking is controlled by inverse powers of the spin. In such cases the twist conformal blocks can be decomposed into a sequence of functions which we systematically construct. Decomposing the four-point correlator in this basis turns crossing symmetry into an algebraic problem. Our method can be applied to a wide spectrum of conformal field theories in any number of dimensions and at any order in the breaking parameter. As an example, we compute the spectrum of various theories around generalized free fields.

  8. Large Solar Flares and Sheared Magnetic Field Configuration

    NASA Technical Reports Server (NTRS)

    Choudhary, Debi Prasad

    2001-01-01

    This Comment gives additional information about the nature of flaring locations on the Sun described in the article "Sun unleashes Halloween storm", by R. E. Lopez, et al. What causes the large explosions from solar active regions that unleash huge magnetic storms and adverse space weather? It is now beyond doubt that the magnetic field in solar active regions harbors free energy that is released during these events. Direct measurements of the longitudinal and transverse components of active region magnetic fields with the vector magnetograph at NASA Marshall Space Flight Center (MSFC), taken on a regular basis for the last 30 years, have found key signatures of the locations of powerful flares. A vector magnetograph detects and measures the magnetic shear, which is the deviation of the observed transverse magnetic field direction from the potential field. The sheared locations possess abundant free magnetic energy for solar flares. In addition to active region NOAA 10486, the one that produced the largest flares last October, the NASA/MSFC vector magnetograph has observed several other such complex super active regions, including NOAA 6555 and 6659.

  9. 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)

  10. 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.

  11. Large perturbation flow field analysis and simulation for supersonic inlets

    NASA Technical Reports Server (NTRS)

    Varner, M. O.; Martindale, W. R.; Phares, W. J.; Kneile, K. R.; Adams, J. C., Jr.

    1984-01-01

    An analysis technique for simulation of supersonic mixed compression inlets with large flow field perturbations is presented. The approach is based upon a quasi-one-dimensional inviscid unsteady formulation which includes engineering models of unstart/restart, bleed, bypass, and geometry effects. Numerical solution of the governing time dependent equations of motion is accomplished through a shock capturing finite difference algorithm, of which five separate approaches are evaluated. Comparison with experimental supersonic wind tunnel data is presented to verify the present approach for a wide range of transient inlet flow conditions.

  12. Quasi-single field inflation with large mass

    SciTech Connect

    Chen, Xingang; Wang, Yi E-mail: tririverwangyi@gmail.com

    2012-09-01

    We study the effect of massive isocurvaton on density perturbations in quasi-single field inflation models, when the mass of the isocurvaton M becomes larger than the order of the Hubble parameter H. We analytically compute the correction to the power spectrum, leading order in coupling but exact for all values of mass. This verifies the previous numerical results for the range 0 < M < 3H/2 and shows that, in the large mass limit, the correction is of order H{sup 2}/M{sup 2}.

  13. 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.

  14. 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

  15. 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.

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. Transport in organic semiconductors in large electric fields: From thermal activation to field emission

    NASA Astrophysics Data System (ADS)

    Worne, J. H.; Anthony, J. E.; Natelson, D.

    2010-02-01

    Understanding charge transport in organic semiconductors in large electric fields is relevant to many applications. We present transport measurements in organic field-effect transistors based on poly(3-hexylthiophene) and 6,13-bis(triisopropyl-silylethynyl) (TIPS) pentacene with short channels, from room temperature down to 4.2 K. Near 300 K transport in both systems is well described by thermally assisted hopping with Poole-Frenkel-type enhancement of the mobility. At low temperatures and large gate voltages, transport in both materials becomes nearly temperature independent, crossing over into field-driven tunneling. These data, particularly in TIPS-pentacene, show that great caution must be exercised when considering more exotic (e.g., Tomonaga-Luttinger liquid) interpretations of transport.

  3. 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.

  4. Large-scale velocity fields. [of solar rotation

    NASA Technical Reports Server (NTRS)

    Howard, Robert F.; Kichatinov, L. L.; Bogart, Richard S.; Ribes, Elizabeth

    1991-01-01

    The present evaluation of recent observational results bearing on the nature and characteristics of solar rotation gives attention to the status of current understanding on such large-scale velocity-field-associated phenomena as solar supergranulation, mesogranulation, and giant-scale convection. Also noted are theoretical suggestions reconciling theory and observations of giant-scale solar convection. The photosphere's global meridional circulation is suggested by solar rotation models requiring pole-to-equator flows of a few m/sec, as well as by the observed migration of magnetic activity over the solar cycle. The solar rotation exhibits a latitude and cycle dependence which can be understood in terms of a time-dependent convective toroidal roll pattern.

  5. TRM in Low Magnetic Fields: a minimum field that can be recorded by large multidomain grains

    NASA Astrophysics Data System (ADS)

    Kletetschka, G.; Fuller, M. D.; Kohout, T.; Wasilewski, P. J.; Bervera, E.; Ness, N. F.; Acuna, M. H.

    2006-05-01

    Thermally acquired remanent magnetization is important for the estimation of the past magnetic field present at the time of cooling. Rocks that cool slowly commonly contain magnetic grains of millimeter scale. This study investigated 1mm-sized magnetic minerals of iron, iron-nickel, magnetite, and hematite and concluded that the thermoremanent magnetization (TRM) acquired by these grains did not accurately record the ambient magnetic field less than 1 microTesla. Instead the TRM of these grains fluctuated around a constant value. Consequently, the magnetic grain ability to record the ambient field accurately is reduced. Above the critical field, TRM acquisition is governed by an empirical law and is proportional to saturation magnetization (Ms). The efficiency of TRM is inversely proportional to the mineral's saturation magnetization Ms and is related to the number of domains in the magnetic grains. The absolute field for which we have an onset of TRM sensitivity is inversely proportional to the size of the magnetic grain. These results have implications for previous reports of random directions in meteorites during alternating field demagnetization, or thermal demagnetization of TRM. Extraterrestrial magnetic fields in our solar system are weaker than the geomagnetic field by several orders of magnitude. Extraterrestrial rocks commonly contain large iron-based magnetic minerals as a common part of their composition, and therefore ignoring this behavior of multidomain grains can result in erroneous paleofield estimates.

  6. TRM in low magnetic fields: a minimum field that can be recorded by large multidomain grains

    NASA Astrophysics Data System (ADS)

    Kletetschka, Gunther; Fuller, Michael D.; Kohout, Tomas; Wasilewski, Peter J.; Herrero-Bervera, Emilio; Ness, Norman F.; Acuna, M. H.

    2006-03-01

    Thermally acquired remanent magnetization is important for the estimation of the past magnetic field present at the time of cooling. Rocks that cool slowly commonly contain magnetic grains of millimeter scale. This study investigated 1-mm-sized magnetic minerals of iron, iron-nickel, magnetite, and hematite and concluded that the thermoremanent magnetization (TRM) acquired by these grains did not accurately record the ambient magnetic fields less than 1 μT. Instead, the TRM of these grains fluctuated around a constant value. Consequently, the magnetic grain ability to record the ambient field accurately is reduced. Above the critical field, TRM acquisition is governed by an empirical law and is proportional to saturation magnetization ( Ms). The efficiency of TRM is inversely proportional to the mineral's saturation magnetization Ms and is related to the number of domains in the magnetic grains. The absolute field for which we have an onset of TRM sensitivity is inversely proportional to the size of the magnetic grain. These results have implications for previous reports of random directions in meteorites during alternating field demagnetization, or thermal demagnetization of TRM. Extraterrestrial magnetic fields in our solar system are weaker than the geomagnetic field by several orders of magnitude. Extraterrestrial rocks commonly contain large iron-based magnetic minerals as a common part of their composition, and therefore ignoring this behavior of multidomain grains can result in erroneous paleofield estimates.

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. Tomographic Measurement Of Laser-Bored Holes

    NASA Technical Reports Server (NTRS)

    Willenberg, James D.; Roy, Jack; Spiegel, Lyle B.

    1992-01-01

    Nondestructive technique detects internal variations in arrays of small holes. Inspection method checks laser-bored holes for accuracy. Combines computed tomography and digital laminography. Both types of views made at many parallel planes within plate. System prints out tables of measured and standard deviation of diameter at all planes for each hole.

  12. Talc Pleurodesis Through Small-Bore Percutaneous Tubes

    SciTech Connect

    Bloom, Allan I.; Wilson, Mark W.; Kerlan, Robert K. Jr.; Gordon, Roy L.; LaBerge, Jeanne M.

    1999-09-15

    Pleurodesis using talc as the sclerosing agent is an effective procedure for preventing reaccumulation of malignant pleural effusions. Because of its thickness, the talc slurry is usually instilled through large bore (20-28 Fr), surgically placed thorocostomy tubes. However, these tubes often cause considerable patient discomfort. Herein we report a series of eight patients in whom the talc slurry was inserted through 10 and 12 Fr percutaneous chest tubes. Six of the eight patients (75%) had a successful pleurodesis without a reaccumulation of fluid. We conclude that this is an acceptable method for treating patients with malignant pleural effusions.

  13. 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.

  14. A cradle-shaped gradient coil to expand the clear-bore width of an animal MRI scanner.

    PubMed

    Gilbert, K M; Gati, J S; Klassen, L M; Menon, R S

    2010-01-21

    The never ending quest for higher magnetic field strengths in MRI and MRS has led to small and medium bore scanners at 9.4 T and above for both human and animal use; however, these bore diameters restrict the size of object that can be accommodated when using a conventional gradient coil. By replacing a cylindrical gradient-coil insert with a single-sided gradient coil, the scanner's functionality can be extended to include localized imaging of wider samples. As a prototype, a three-axis, cradle-shaped gradient coil was designed, fabricated and implemented in a 9.4 T animal MRI scanner. Since gradient fields are required only to be monotonic over the desired field of view, the cradle gradient coil was designed to produce high gradient efficiencies (up to 2.25 mT m(-1) A(-1) over a 5 cm imaging region) at the expense of gradient linearity. A dedicated three-dimensional algorithm was developed to correct the resultant image distortion. Preliminary images of a grid phantom and a mouse demonstrated the fidelity of the algorithm in correcting image distortion of greater than 200%. Eddy currents were measured along each gradient axis. A large 65.2 (Hz mT(-1) m) B(0) eddy current was produced by the y-axis, suggesting potential limitations of single-sided gradient coils.

  15. Quantum magnetism in low dimensions and large magnetic fields

    NASA Astrophysics Data System (ADS)

    Giamarchi, Thierry

    2014-03-01

    The ability to control the properties of magnetic insulators by magnetic fields large enough to fully polarize the system has opened a host of possibilities. In addition to the intrinsic interest of such questions for magnetic systems, is has been shown that such systems could be efficiently used as quantum simulators to emulate problems pertaining to itinerant fermionic or bosonic systems. The magnetic field can then be viewed as similar to a gate voltage controlling the number of ``particles'' allowing an unprecedented level of control. In parallel with the experimental developments, progress on the theoretical front both on the numerical and the analytical side, have allowed a remarkable level of accuracy in obtaining the physical properties and in particular the correlation functions of these systems. A comparison between theoretical predictions without adjustable parameters or fudging with results from NMR, Neutrons or other probes such as ESR is thus now possible. This has allowed for example to test quantitatively the physics of Tomonaga-Luttinger liquids and also to tackle the effects of the interactions between spinons by comparing the physics of weak rung ladders with the one of strong rung ones. Comparison between the neutron results and theoretical calculations of the correlation functions has also been demonstrated as a way to reconstruct efficiently the Hamiltonian from the experimental data. I will review the recent results obtained in this domain with the different experimental compounds and will discuss the open questions and challenges. This concerns in particular the issues of finite temperatures, higher dimensional systems and effects of disorder. This work was supported in part by the Swiss NSF under MaNEP and Division II

  16. Volumetric thermoacoustic imaging over large fields of view.

    PubMed

    Roggenbuck, M A; Walker, R D; Catenacci, J W; Patch, S K

    2013-01-01

    The thermoacoustic (TA) contrast mechanism relies on rapid tissue heating and subsequent thermal expansion. TA computerized tomography (TCT) is therefore inverse source imaging. The TA contrast mechanism provides information complementary to that revealed by current diagnostic imaging techniques, but has been limited to just a few centimeters depth penetration. In this article, whole organ TCT is demonstrated on a large swine kidney. TA sinograms show that TA signal generated by high-power, very high frequency (VHF) electromagnetic pulses is detectable after travel through 6 cm of soft tissue. Reconstructed images provide resolution sufficient to track progression of calyces throughout the kidney. Because VHF electromagnetic energy can easily penetrate the abdomen of large adults, our results indicate that whole organ TA imaging is feasible in vivo, provided an ultrasound array can be placed near the region of interest. Pulses of 22 to 25 kW with carrier frequency 108 MHz and 900 ns pulse width were applied at a 100-Hz pulse repetition frequency to generate a 13-kV/m electric field and TA signal. Only 2 to 5 mJ was absorbed in the kidney per pulse, causing temperature and pressure jumps of only 5e-6°C and 4 Pa averaged throughout the 141-g specimen. TA pulses were detected by focused, single-element transducers (V306, Panametrics), amplified by 54 dB and averaged 64 times to reduce electronic noise. Data were measured over a cylindrical measurement aperture of radius 5 cm and length 6 cm, by rotating the specimen 1.8 degrees between tomographic views and translating 2 mm between slices. Reconstruction via filtered backprojection yields in-plane resolution better than 5 mm, but suffers significant blurring between planes. Both in-plane resolution and slice sensitivity profile could be improved by applying shorter irradiation pulsewidths and using less directional transducers. Both hardware changes would be recommended for a clinical prototype.

  17. Magnetic fields around AGNs at large and small scales

    NASA Astrophysics Data System (ADS)

    Tyul'bashev, S. A.

    2002-06-01

    The dipole structure of the magnetic field on distances ge 1 kpc from an active galactic nucleus is discussed. Two different models of the magnetic field around a supermassive black hole on the scale of the accretion disk are tested. The first model suggests a superstrong field of the order of 1010 Gauss (Kardashev \\cite{Kardashev95}), the other one proposed by Field & Rodgers (\\cite{Field93}) predicts much lower values ( ~ 104 Gauss).

  18. 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.

  19. 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

  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. 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.

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Wood-boring beetles in homes

    Treesearch

    V.R. Lewis; S.J. Seybold

    2010-01-01

    Three groups of wood-boring beetles—powderpost, deathwatch, and false powderpost (Table 1)—invade and damage wood furniture as well as structural and decorative wood inside of buildings. The beetle larvae feed in and do most of the damage to wood, and when they reach the adult stage, they emerge through round exit holes, which they create by chewing through the wood...

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Control paraffin with well bore insulating gelled fluids

    SciTech Connect

    Yousif, M.H.; Young, D.B. ); Black, J.W.

    1994-10-01

    A variety of techniques are used to treat paraffin, including scrapping, pigging, heating, insulating and solvent usage. Well bore insulating fluids control paraffin deposition in offshore wells by producing a high cloud point oil from a relatively cold reservoir. Produced hydrocarbons exhibit large pressure and temperature changes from the formation to the surface facilities. This changes their phase behavior and consequently their carrying capacity of the dissolved paraffins. Paraffins can drop out in the producing formation, subsurface pumps, tubing, flowline, separators and storage tanks. Paraffins can be low molecular weight n-alkanes (C20-C40) or high molecular weight iso-alkanes and cyclic alkanes. Heat convection through the annulus is the main mechanism by which produced fluids lose heat to surrounding formations. Consequently, selecting a well bore insulating fluid should not be based entirely on thermal conductivity of the fluid. Although their thermal conductivity is only 2.5% that of water, fluids like mineral oil or diesel could transfer as much heat as water under the same temperature gradient. Testing shows that the viscosity of the annular fluid is the key parameter that needs to be increased to minimize annular convective heat loses.

  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. 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.

  19. 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

  20. Imprints of massive primordial fields on large-scale structure

    NASA Astrophysics Data System (ADS)

    Dimastrogiovanni, Emanuela; Fasiello, Matteo; Kamionkowski, Marc

    2016-02-01

    Attention has focussed recently on models of inflation that involve a second or more fields with a mass near the inflationary Hubble parameter H, as may occur in supersymmetric theories if the supersymmetry-breaking scale is not far from H. Quasi-single-field (QsF) inflation is a relatively simple family of phenomenological models that serve as a proxy for theories with additional fields with masses m~ H. Since QsF inflation involves fields in addition to the inflaton, the consistency conditions between correlations that arise in single-clock inflation are not necessarily satisfied. As a result, correlation functions in the squeezed limit may be larger than in single-field inflation. Scalar non-Gaussianities mediated by the massive isocurvature field in QsF have been shown to be potentially observable. These are especially interesting since they would convey information about the mass of the isocurvature field. Here we consider non-Gaussian correlators involving tensor modes and their observational signatures. A physical correlation between a (long-wavelength) tensor mode and two scalar modes (tss), for instance, may give rise to local departures from statistical isotropy or, in other words, a non-trivial four-point function. The presence of the tensor mode may moreover be inferred geometrically from the shape dependence of the four-point function. We compute tss and stt (one soft curvature mode and two hard tensors) bispectra in QsF inflation, identifying the conditions necessary for these to "violate" the consistency relations. We find that while consistency conditions are violated by stt correlations, they are preserved by the tss in the minimal QsF model. Our study of primordial correlators which include gravitons in seeking imprints of additional fields with masses m~ H during inflation can be seen as complementary to the recent ``cosmological collider physics'' proposal.

  1. Imprints of massive primordial fields on large-scale structure

    SciTech Connect

    Dimastrogiovanni, Emanuela; Fasiello, Matteo; Kamionkowski, Marc E-mail: matteorf@stanford.edu

    2016-02-01

    Attention has focussed recently on models of inflation that involve a second or more fields with a mass near the inflationary Hubble parameter H, as may occur in supersymmetric theories if the supersymmetry-breaking scale is not far from H. Quasi-single-field (QsF) inflation is a relatively simple family of phenomenological models that serve as a proxy for theories with additional fields with masses m∼ H. Since QsF inflation involves fields in addition to the inflaton, the consistency conditions between correlations that arise in single-clock inflation are not necessarily satisfied. As a result, correlation functions in the squeezed limit may be larger than in single-field inflation. Scalar non-Gaussianities mediated by the massive isocurvature field in QsF have been shown to be potentially observable. These are especially interesting since they would convey information about the mass of the isocurvature field. Here we consider non-Gaussian correlators involving tensor modes and their observational signatures. A physical correlation between a (long-wavelength) tensor mode and two scalar modes (tss), for instance, may give rise to local departures from statistical isotropy or, in other words, a non-trivial four-point function. The presence of the tensor mode may moreover be inferred geometrically from the shape dependence of the four-point function. We compute tss and stt (one soft curvature mode and two hard tensors) bispectra in QsF inflation, identifying the conditions necessary for these to 'violate' the consistency relations. We find that while consistency conditions are violated by stt correlations, they are preserved by the tss in the minimal QsF model. Our study of primordial correlators which include gravitons in seeking imprints of additional fields with masses m∼ H during inflation can be seen as complementary to the recent ''cosmological collider physics'' proposal.

  2. 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

  3. 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.

  4. 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.

  5. 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

  6. A comparison of dedicated 1.0 T extremity MRI vs. large-bore 1.5 T MRI for semiquantitative whole organ assessment of osteoarthritis: the MOST study

    PubMed Central

    Roemer, F.W.; Lynch, J.A.; Niu, J.; Zhang, Y.; Crema, M.D.; Tolstykh, I.; El-Khoury, G.Y.; Felson, D.T.; Lewis, C.E.; Nevitt, M.C.; Guermazi, A.

    2009-01-01

    Objective To date semiquantitative whole-organ scoring of knee osteoarthritis (OA) relies on 1.5 T MRI systems. Less costly 1.0 T extremity systems have been introduced that offer superior patient comfort, but may have limitations concerning field-of-view and image quality. The aim of this study was to compare SQ scoring on a 1.0 T system using 1.5 T MRI as the standard of reference. Methods The Multicenter Osteoarthritis (MOST) Study is a longitudinal study of individuals who have or are at high risk for knee OA. A sample of 53 knees was selected in which MRI was performed on a 1.0 T extremity system as well as on a 1.5 T scanner applying a comparable sequence protocol. MRIs were read according to the Whole Organ Magnetic Resonance Imaging Score (WORMS) score. Agreement was determined using weighted kappa statistics. Sensitivity, specificity and accuracy were assessed using the 1.5 T readings as the reference standard. In addition the number of non-readable features was assessed. Results Agreement (w-kappa) for 7 main WORMS features (cartilage, bone marrow lesions, osteophytes, meniscal damage and extrusion, synovitis, effusion) ranged between 0.54 (synovitis) and 0.75 (cartilage). Sensitivity ranged between 68.1% (meniscal damage) and 88.1% (effusion). Specificity ranged between 63.6% (effusion) and 96.4% (bone marrow lesions). Although the overall rate of non-readable features was very low, it was higher for the 1.0 T system (1.9% vs 0.2%). Conclusions Semiquantitative whole organ scoring can be performed using a 1.0 T peripheral scanner with a moderate to high degree of agreement and accuracy compared to SQ assessment using a 1.5 T whole body scanner. Our results are comparable to the published inter- and intra observer exercises obtained from 1.5 T systems. Sensitivity to change of longitudinal scoring was not evaluated in this cross-sectional design and should be investigated in future validation studies. PMID:19766580

  7. 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…

  8. 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.

  9. Large-area Overhead Manipulator for Access of Fields

    USDA-ARS?s Scientific Manuscript database

    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...

  10. 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.

  11. 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.

  12. 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.

  13. Intraoperative wide bore nasogastric tube knotting: A rare incidence

    PubMed Central

    Lamba, Sangeeta; Sethi, Surendra K.; Khare, Arvind; Saini, Sudheendra

    2016-01-01

    Nasogastric tubes are commonly used in anesthetic practice for gastric decompression in surgical patients intraoperatively. The indications for its use are associated with a number of potential complications. Knotting of small-bore nasogastric tubes is usually common both during insertion and removal as compared to wide bore nasogastric tubes. Knotting of wide bore nasogastric tube is a rare complication and if occurs usually seen in long standing cases. We hereby report a case of incidental knotting of wide bore nasogastric tube that occurred intraoperatively. PMID:26957700

  14. 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.

  15. 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.

  16. 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.

  17. Crystallization of Calcium Carbonate in a Large Scale Field Study

    NASA Astrophysics Data System (ADS)

    Ueckert, Martina; Wismeth, Carina; Baumann, Thomas

    2017-04-01

    The long term efficiency of geothermal facilities and aquifer thermal energy storage in the carbonaceous Malm aquifer in the Bavarian Molasse Basin is seriously affected by precipitations of carbonates. This is mainly caused by pressure and temperature changes leading to oversaturation during production. Crystallization starts with polymorphic nuclei of calcium carbonate and is often described as diffusion-reaction controlled. Here, calcite crystallization is favoured by high concentration gradients while aragonite crystallization is occurring at high reaction rates. The factors affecting the crystallization processes have been described for simplified, well controlled laboratory experiments, the knowledge about the behaviour in more complex natural systems is still limited. The crystallization process of the polymorphic forms of calcium carbonate were investigated during a heat storage test at our test site in the eastern part of the Bavarian Molasse Basin. Complementary laboratory experiments in an autoclave were run. Both, field and laboratory experiments were conducted with carbonaceous tap water. Within the laboratory experiments additionally ultra pure water was used. To avoid precipitations of the tap water, a calculated amount of {CO_2} was added prior to heating the water from 45 - 110°C (laboratory) resp. 65 - 110°C (field). A total water volume of 0.5 L (laboratory) resp. 1 L (field) was immediately sampled and filtrated through 10 - 0.1

  18. 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.

  19. 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.

  20. 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.

  1. 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).

  2. 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.

  3. Surveys of ultraviolet-excess quasar candidates in large fields

    NASA Astrophysics Data System (ADS)

    Gosset, E.; Moreau, O.; Surdej, J.; Swings, J.-P.; Arp, H. C.

    1997-06-01

    We describe the results of a survey for moderately bright quasars performed in a 20.6-square-degree field around the galaxy NGC 450. The quasar candidates were selected on the basis of their ultraviolet excess: by comparative visual inspection of the double image of each single object on a U/B dual-exposure Schmidt photographic plate, 95 primary and 45 secondary quasar candidates were selected on the basis of their $U$ image being too bright. The spectroscopic identification of the primary candidates led to the discovery of 59 bona fide quasars (out of which 6 were previously known). The Palomar Schmidt plate was digitised using the MAMA measuring machine and the outcoming data reduced using ad hoc procedures. A photometric calibration allowed us to derive values for the limiting magnitudes and for the U-B index selection threshold of the survey. A catalogue containing 60 quasars is presented with accurate positions, magnitudes and additional information such as redshifts. We studied the spatial distribution of the objects and detected, for the quasars of our sample, a significant deviation from randomness in the form of a propensity to cluster in pairs on the celestial sphere with a typical scale of about 10 arcmin. We also formally detected a tendency towards a 3-D clustering, but this result is induced by a single pair of quasars. A forthcoming paper will deal with a similar work performed in a field around NGC 520; the latter field is located directly to the North of the present one and slightly overlaps it. Based on observations acquired at the Mount Palomar and Las Campanas Observatories as well as at the European Southern Observatory. Also based on Schmidt-plate digitisations performed with the MAMA measuring machine of C.A.I. (I.N.S.U., Paris).

  4. A physical interpretation of field observations that precede large earthquakes

    NASA Astrophysics Data System (ADS)

    Suyehiro, K.; Sacks, S. I.; Rydelek, P. A.; Smith, D. E.; Takanami, T.

    2016-12-01

    A cellular automaton model of earthquake faulting adopting Coulomb's failure criterion developed by Sacks and Rydelek (1995) successfully generates catalogs that satisfy Gutenberg-Richter's Law, the observed decreases in b-value before large events, as well as the propagation of the rupture front. Model runs indicate that redistributed stresses remain on the ruptured area and that some slips recur on the same cells forming dynamic asperities of high slips. We found that the observed magnitude-dependent seismicity quiescence can be explained by the introduction of dilatancy hardening into the model. Only a few % of the total number of model cells need be strengthened by a small amount. This indicates the difficulty of detecting their presence using seismic imaging. However, the observed long term ( years) temporal changes in seismicity, gravity, and electrical resistivity may be causally linked to the volume change from microfractures and the effect of pore pressure changes on fault strength. Our model predicts the process occurs at points sparcely distributed. Water migrations into unfilled microfractures act to lower the strength, thus promoting the occurrence of seismic slips. These slips may expel water that will influence aquifer levels, which may be observed at regional water wells. Drilling in seismic fault zones, such as at the 1995 Kobe earthquake fault, has revealed that the permeability on the main fault plane was many orders of magnitude higher than the surrounding rocks. We suggest the same water migration process at highly permeable zone can occur at short time scale to grow into a large magnitude slip or may manifest as a slow slip. The aftershock sequence of the 1978 Izu-Oshima earthquake shows that it overlaps the inferred slow slip on the fault following the main shock, thus suggesting that a fault can slip in various ways in the same time interval. We propose new observations that are sensitive to crustal water migration such as vertical

  5. On the response of large systems to electrostatic fields

    SciTech Connect

    Springborg, Michael; Kirtman, Bernard

    2015-01-22

    By modifying the surfaces of a macroscopic regular system it is possible to modify the dipole moment per unit by an amount equal to a lattice vector times the elementary charge. Alternatively, we may ignore the surfaces and treat the system as being infinite and periodic. In that event the dipole moment per unit is determined only up to an additive term equal to a lattice vector times the elementary charge. Beyond mathematical arguments we show, through model calculations, that the two cases are completely equivalent, even though the origin of the additive term is very different. The response of extended systems to electrostatic fields — including internal structure, piezoelectricity, bulk charge density, and (hyper)polarizabilities — depends upon this term and is, thereby, surface-dependent. The case of piezoelectricity is analyzed in some detail.

  6. 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.

  7. 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.

  8. 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.

  9. Pre-polarization fields for earth's field NMR: Fast discharge for use with short T1 and large coils

    NASA Astrophysics Data System (ADS)

    Conradi, Mark S.; Altobelli, Stephen A.; Sowko, Nicholas J.; Conradi, Susan H.; Fukushima, Eiichi

    2017-08-01

    The sensitivity of earth's field NMR is greatly increased by the use of a pre-polarizing field Bp. When used with short T1 samples, the field must be decreased rapidly to avoid loss of the pre-polarized magnetization by relaxation. Such a rapid decrease in the field requires rapid discharge (∼10 ms) of a large stored magnetic field energy (∼700 J). In addition, in order that the full pre-polarized magnetization be available for the subsequent pulse sequence, the field discharge should be adiabatic. This requirement is difficult to fulfill in cases where Bp is not everywhere parallel to the earth's field, such as with a large surface coil. Circuitry for rapid and controlled discharge is presented. Simulations and experiments confirm the importance of both of these conditions.

  10. Pre-polarization fields for earth's field NMR: Fast discharge for use with short T1 and large coils.

    PubMed

    Conradi, Mark S; Altobelli, Stephen A; Sowko, Nicholas J; Conradi, Susan H; Fukushima, Eiichi

    2017-08-01

    The sensitivity of earth's field NMR is greatly increased by the use of a pre-polarizing field Bp. When used with short T1 samples, the field must be decreased rapidly to avoid loss of the pre-polarized magnetization by relaxation. Such a rapid decrease in the field requires rapid discharge (∼10ms) of a large stored magnetic field energy (∼700J). In addition, in order that the full pre-polarized magnetization be available for the subsequent pulse sequence, the field discharge should be adiabatic. This requirement is difficult to fulfill in cases where Bp is not everywhere parallel to the earth's field, such as with a large surface coil. Circuitry for rapid and controlled discharge is presented. Simulations and experiments confirm the importance of both of these conditions. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. 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.

  12. Sedimentary signatures of tidal bores: a brief synthesis

    NASA Astrophysics Data System (ADS)

    Tessier, Bernadette; Furgerot, Lucille; Mouazé, Dominique

    2017-08-01

    This article aims at presenting a brief synthesis of sedimentary signatures assigned to tidal bore dynamics and impacts. According to the few studies published until now on tidal bore-induced facies within inner estuarine tidal channel infilling successions, only two major signatures can be reported: (1) soft sediment deformations (SSDs) due to overpressure linked to sudden water level elevation, high shear stress and vertical velocity acceleration below the tidal bore front and secondary waves; SSDs may be present throughout the channel infill succession, with the general exception of the uppermost part; tidal bore-induced SSDs have been described only in modern facies; (2) tidal bore couplets (TBCs) formed by an erosional surface overlain by massive sand drapes, related to the reworking of the sediment bottom during tidal bore passage; TBCs were first described in the ancient record. Studies in modern estuaries demonstrate that TBCs evolve towards tidal bore sequences from the tidal channel bottom (subtidal to low intertidal facies) to tidal channel bank (low to mid intertidal facies). In mid to upper intertidal facies, the occurrence of thicker-than-average tidal rhythmites, reflecting higher-than-average suspended sediment concentrations, are also considered as a possible signature of tidal bore dynamics.

  13. 6. VIEW OF BORING MILL. Chuck action of locomotive wheel ...

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

    6. VIEW OF BORING MILL. Chuck action of locomotive wheel Wheel weight 1200 pounds, 3'-0' diameter. Table 53' in diameter Wheel is 48'. Largest hole that can be bored is 9-1/2' plus (GE axle is 10'). - Juniata Shops, Erecting Shop & Machine Shop, East of Fourth Avenue, between Fourth & Fifth Streets, Altoona, Blair County, PA

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

    USDA-ARS?s Scientific Manuscript database

    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...

  15. 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

  16. 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.

  17. New numerical model of mesospheric bores: Observational implications

    NASA Astrophysics Data System (ADS)

    Picard, R. H.; Cohen, E.; Dewan, E. M.; Winick, J. R.; Taylor, M. J.; She, C.-Y.

    Mesospheric bores are space-time varying frontal structures that may play a role in transport and coupling between horizontally separated regions. We examine the observational implications of a new numerical model of the generation and propagation of mesospheric bores. The bores develop as long-wave excitations in mesospheric wave ducts, formed by the temperature and wind structure, in much the same way as they do in the tropospheric boundary-layer duct. However, while the boundary-layer duct has a clamped ground boundary (zero vertical displacement), the embedded mesospheric duct has two free boundaries, which results in some differences in behavior. With a separability assumption valid in the long-wave limit, the fluid equations separate into a product of solutions of the Taylor-Goldstein equation describing the vertical dependence of the mode function and of the Benjamin-Davis-Ono (BDO) equation describing the horizontal and time behavior. We compare results of the numerical model with the analytic model of Dewan and Picard (1998) that is based on Lighthill's channel-bore solutions. The numerical model leads to predictions of new or as-yet-unobserved phenomena, including (1) the conceivable existence of bores in Doppler ducts, (2) the existence of a fast sinuous-mode bore with no channel-bore analogue having phase speeds of 150-180 m/s, and (3) the possibility of foaming or turbulent (non-undular) bores. Following Christie (1989), we model the turbulent dissipation processes in the latter case by including a Burgers-type term in the BDO equation. We also discuss the response of emitted radiance to bores and compare model predictions with recent bore observations accompanied by simultaneous lidar data [Smith et al., 2001; She et al., 2004].

  18. 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.

  19. 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

  20. Flow and turbulence structure in a hypertidal estuary with the world's biggest tidal bore

    NASA Astrophysics Data System (ADS)

    Tu, Junbiao; Fan, Daidu

    2017-04-01

    Turbulent and flow structure associated with breaking tidal bores are deliberately investigated on the basis of field measurements. High-resolution velocity and hydrographic data are collected in the middle Qiantang Estuary by a vertical array of acoustic Doppler velocimeters and optical backscatter sensors, collaborated with a bottom-mounted acoustic Doppler current profiler. Besides obvious variations in diurnal and spring-neap tidal cycles, the estuarine dynamics is featured by extreme asymmetry in flood and ebb tides. The flood tide is abnormally accelerated to generate tidal bores at the first 10 min or more, with breaking or undular configurations at the front. The occurrence of peak flow velocity, turbulent kinetic energy (TKE), and TKE dissipation rate (ɛ) is definitely associated with breaking bores, with their values several times to 2 orders of magnitude larger than the corresponding secondary peak values during the maximum ebb flows. Flow and turbulence dynamics are significantly affected by the tidal-bore Froude number. A sandwich ɛ structure is clear exhibited with the maximum value at the surface, secondary maximum near the bed, and the minimum at the intermediate. Dual TKE sources are indicated by an approximate local balance between shear production and dissipation near the bottom, and a top-down TKE dissipation using the modified Froude scaling in the vertical water column. The highly elevated dissipation by breaking bores is comparable to that by intense breaking waves in the surf zone, and the former potentially penetrates the entire water column to produce extreme sediment-resuspension events in combination with intense bottom shear stress.

  1. 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.

  2. 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.

  3. 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.

  4. The age and phylogeny of wood boring weevils and the origin of subsociality.

    PubMed

    Jordal, Bjarte H; Sequeira, Andrea S; Cognato, Anthony I

    2011-06-01

    A large proportion of the hyperdiverse weevils are wood boring and many of these taxa have subsocial family structures. The origin and relationship between certain wood boring weevil taxa has been problematic to solve and hypotheses on their phylogenies change substantially between different studies. We aimed at testing the phylogenetic position and monophyly of the most prominent wood boring taxa Scolytinae, Platypodinae and Cossoninae, including a range of weevil outgroups with either the herbivorous or wood boring habit. Many putatively intergrading taxa were included in a broad phylogenetic analysis for the first time in this study, such as Schedlarius, Mecopelmus, Coptonotus, Dactylipalpus, Coptocorynus and allied Araucariini taxa, Dobionus, Psepholax, Amorphocerus-Porthetes, and some peculiar wood boring Conoderini with bark beetle behaviour. Data analyses were based on 128 morphological characters, rDNA nucleotides from the D2-D3 segment of 28S, and nucleotides and amino acids from the protein encoding gene fragments of CAD, ArgK, EF-1α and COI. Although the results varied for some of the groups between various data sets and analyses, one may conclude the following from this study: Scolytinae and Platypodinae are likely sister lineages most closely related to Coptonotus; Cossoninae is monophyletic (including Araucariini) and more distantly related to Scolytinae; Amorphocerini is not part of Cossoninae and Psepholax may belong to Cryptorhynchini. Likelihood estimation of ancestral state reconstruction of subsociality indicated five or six origins as a conservative estimate. Overall the phylogenetic results were quite dependent on morphological data and we conclude that more genetic loci must be sampled to improve phylogenetic resolution. However, some results such as the derived position of Scolytinae were consistent between morphological and molecular data. A revised time estimation of the origin of Curculionidae and various subfamily groups were made using

  5. 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.

  6. Quasi-stationary fluid theory of the hole-boring process

    SciTech Connect

    Pei, Zhikun; Shen, Baifei Shi, Yin; Ji, Liangliang; Wang, Wenpeng; Zhang, Xiaomei; Zhang, Lingang; Xu, Tongjun; Liu, Chen

    2016-04-15

    We present a quasi-stationary fluid theory to precisely describe the hole-boring process. The corresponding distributions of the electrostatic field and the particle density are theoretically obtained, which give more details than the previous stationary theory. The theoretical result is confirmed by one-dimensional particle-in-cell simulations. Such quasi-stationary fluid theory may help in understanding the basic mechanisms of ion acceleration in the radiation pressure acceleration.

  7. Field-flow fractionation of nucleic acids and proteins under large-scale gradient magnetic fields

    NASA Astrophysics Data System (ADS)

    Iwasaka, M.

    2007-05-01

    For the purpose of developing techniques for separating biological macromolecules, the present study reports a magnetic chromatography system employing high performance liquid chromatography and superconducting magnets of 14 and 5T. We observed chromatograms of catalase and albumin, which were eluded from columns that were exposed to magnetic fields of up to 14T with a maximum gradient of 90T/m. Without the magnetic fields, the chromatograms of the macromolecules showed a clear peak, while the chromatograms changed to have separated peaks for the same molecules after exposure to gradient magnetic fields. When the chromatocolumn was placed so the magnetic forces were opposite to the direction of flow, the albumin molecules separated into two groups. In addition, the chromatograms of catalase exposed to the magnetic fields indicated that the retention times of the two kinds of magnetically separated catalase were relatively changed if the column-field configuration was changed. Probably, the balance of paramagnetism in the heme and diamagnetism in the protein controlled the transport velocity under the influence of the gradient magnetic fields. In addition, the transport velocity of DNA molecules in the flow with a high gradient magnetic field was observed using a time-resolved spectrophotometric system.

  8. 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

  9. 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.

  10. Vacuum insulated room temperature bore horizontal cryostat for 4-Tesla superconducting magnet

    SciTech Connect

    Sundar Rajan, S.; Sinha, A.K.; Sachan, Udai G.P.; Malhotra, Sanjay; Taly, Y.K.; Krishnamurthy, N.

    2014-07-01

    4-Tesla warm bore superconducting magnet is being constructed at Bhabha Atomic Research Centre in India. The adiabatically cooled superconducting magnet will be used for corrosion and Magneto Hydro Dynamic (MHD) studies related to development of Lead Lithium Cooled Ceramic Breeder (LLCB) test blanket module (TBM). Magnet aperture is of 300 mm diameter and is accessible from both ends. Magnet is completely immersed in liquid helium bath at 4.2K. The stored magnetic energy during normal operation is 2.6 MJ. Huge amount of Lorentz forces acts on the magnet coils during operation. These forces try to axially compress the coils and cause outward radial movement of the conductor. Micro meter movement of the coils result in energy deposition due to large operating fields. This energy, albeit small, is still sufficient to cause quench in the magnet as the heat capacities at cryogenic temperatures are very low. Pre-stressing and banding of the superconducting strands help to overcome conductor movement by increasing structural rigidity. This paper describes the thermal, structural and magnetic design the superconducting solenoid magnet. (author)

  11. 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.

  12. Field Stability of Piezoelectric Shear Properties in PIN-PMN-PT Crystals Under Large Drive Field

    PubMed Central

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

    2013-01-01

    The coercive fields (EC) of Pb(In0.5Nb0.5)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 (PIN-PMN-PT) ternary single crystals were found to be 5 kV/cm, double the value of binary Pb(Mg1/3Nb2/3)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 (Eint), 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 shear-mode 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 Eint, induced by the acceptor-oxygen vacancy defect dipoles. PMID:21342812

  13. 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.

  14. 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

  15. 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

  16. 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

  17. 122. BENCH SHOP, SOUTHWEST CORNER SHOWING WOOD BORING MACHINE. DOOR ...

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

    122. BENCH SHOP, SOUTHWEST CORNER SHOWING WOOD BORING MACHINE. DOOR TO WOODSHOP ON RIGHT. - Gruber Wagon Works, Pennsylvania Route 183 & State Hill Road at Red Bridge Park, Bernville, Berks County, PA

  18. 39. TUNNEL BORE UNDER CONSTRUCTION. VIEW SHOWS LIGHT CONSTRUCTION RAILWAY ...

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

    39. TUNNEL BORE UNDER CONSTRUCTION. VIEW SHOWS LIGHT CONSTRUCTION RAILWAY FOR HAULING MUCK AND SPOIL - Zion-Mount Carmel Highway, Tunnel, Two miles east of Zion Canyon Scenic Drive, Springdale, Washington County, UT

  19. PLANING MILL, FIRST FLOOR INTERIOR, LOOKING WEST. A WHEEL BORING ...

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

    PLANING MILL, FIRST FLOOR INTERIOR, LOOKING WEST. A WHEEL BORING MACHINE AND SUPERVISOR’S OFFICE ARE VISIBLE. - Southern Pacific, Sacramento Shops, Planing Mill, 111 I Street, Sacramento, Sacramento County, CA

  20. 3. VIEW OF BORING MILL IN OPERATION, operator unknown (note ...

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

    3. VIEW OF BORING MILL IN OPERATION, operator unknown (note console in background). - Juniata Shops, Erecting Shop & Machine Shop, East of Fourth Avenue, between Fourth & Fifth Streets, Altoona, Blair County, PA

  1. 4. VIEW OF BORING MILL IN OPERATION, operator unknown (note ...

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

    4. VIEW OF BORING MILL IN OPERATION, operator unknown (note console in background). - Juniata Shops, Erecting Shop & Machine Shop, East of Fourth Avenue, between Fourth & Fifth Streets, Altoona, Blair County, PA

  2. 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

  3. Simplified field-in-field technique for a large-scale implementation in breast radiation treatment

    SciTech Connect

    Fournier-Bidoz, Nathalie; Kirova, Youlia M.; Campana, Francois; Dendale, Remi; Fourquet, Alain

    2012-07-01

    We wanted to evaluate a simplified 'field-in-field' technique (SFF) that was implemented in our department of Radiation Oncology for breast treatment. This study evaluated 15 consecutive patients treated with a simplified field in field technique after breast-conserving surgery for early-stage breast cancer. Radiotherapy consisted of whole-breast irradiation to the total dose of 50 Gy in 25 fractions, and a boost of 16 Gy in 8 fractions to the tumor bed. We compared dosimetric outcomes of SFF to state-of-the-art electronic surface compensation (ESC) with dynamic leaves. An analysis of early skin toxicity of a population of 15 patients was performed. The median volume receiving at least 95% of the prescribed dose was 763 mL (range, 347-1472) for SFF vs. 779 mL (range, 349-1494) for ESC. The median residual 107% isodose was 0.1 mL (range, 0-63) for SFF and 1.9 mL (range, 0-57) for ESC. Monitor units were on average 25% higher in ESC plans compared with SFF. No patient treated with SFF had acute side effects superior to grade 1-NCI scale. SFF created homogenous 3D dose distributions equivalent to electronic surface compensation with dynamic leaves. It allowed the integration of a forward planned concomitant tumor bed boost as an additional multileaf collimator subfield of the tangential fields. Compared with electronic surface compensation with dynamic leaves, shorter treatment times allowed better radiation protection to the patient. Low-grade acute toxicity evaluated weekly during treatment and 2 months after treatment completion justified the pursuit of this technique for all breast patients in our department.

  4. Recognition of Tidal Bore Deposits in the Stratigraphic Record

    NASA Astrophysics Data System (ADS)

    Fielding, C. R.; Joeckel, M.

    2015-12-01

    Tidal bores are upstream-propagating hydraulic jumps that episodically form the leading edge of flood tides in upstream-narrowing, gently sloping, coastal rivers which experience high tidal ranges (6 m+, typically). They attain 9 m in height and can penetrate more than 100 km inboard of a shoreline. The deposits of tidal bores, if they can be confidently diagnosed in ancient successions, constitute an unequivocal line of evidence in support of deposition within the tidal-fluvial zone of a lowland river. Deposits of modern tidal bores have been documented, and two recent studies have interpreted tidal bore deposits in ancient (Jurassic and Pennsylvanian) sedimentary rocks. The ancient tidal bore deposits recognized thus far comprise laterally discontinuous, erosionally-based beds of massive to faintly stratified sand, locally muddy and rich in detrital plant debris. Paleoflow structures, where preserved, indicate upstream-directed flow. The beds are enclosed by other, more pervasively stratified sandstones that were the product of ebb and flood-oriented currents in the ancient tidal rivers. The interpreted bore deposits are anomalous in the context of these normal current deposits, and indicate erosive scouring of the substrate followed by the en masse deposition of sand from suspension and upstream advection. Multiple horizons of putative tidal bore deposits are recognized in both the Jurassic and Pennsylvanian examples, suggesting that they were not the product of low-frequency, high-magnitude events such as tsunami or debris flows. It is anticipated that more examples of ancient tidal bore deposits will come to light now that diagnostic criteria are available, and that these will contribute to the fuller recognition of tidally-modulated fluvial deposits in the rock record.

  5. Observational Implications of a New Model of Mesospheric Bores

    NASA Astrophysics Data System (ADS)

    Picard, R. H.; Cohen, E.; Dewan, E. M.; Winick, J. R.; Taylor, M. J.; She, C. Y.

    2004-05-01

    We examine the observational implications of a new numerical model of the generation and propagation of mesospheric bores. The bores develop as long-wave excitations in mesospheric wave ducts, formed by the temperature and wind structure, in much the same way as they do in the tropospheric boundary-layer duct. However, while the boundary-layer duct has a clamped ground boundary (zero vertical displacement), the embedded mesospheric duct has two free boundaries, which results in some differences in behavior. With a separability assumption valid in the long-wave limit, the fluid equations separate into a product of solutions of the Taylor-Goldstein equation describing the vertical dependence of the mode function and of the Benjamin-Davis-Ono (BDO) equation describing the horizontal and time behavior. We compare results of the numerical model with the analytic model of Dewan and Picard (1998) that is based on Lighthill's channel-bore solutions. The numerical model leads to predictions of new and/or as-yet-unobserved phenomena, including (1) the possible existence of bores in Doppler ducts, (2) the existence of a fast sinuous-mode bore with no channel-bore analogue having phase speeds of 150-180 m/s, and (3) the possibility of foaming or turbulent (non-undular) bores. Following Christie (1989), we model the turbulent dissipation processes in the latter case by including a Burgers-type term in the BDO equation. We also compare model predictions with recent bore observations accompanied by simultaneous lidar data [Smith et al., 2001; She et al., 2004].

  6. 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.

  7. Numerical simulation of atmospheric bore waves on Mars

    NASA Astrophysics Data System (ADS)

    Sta. Maria, Magdalena R. V.; Rafkin, Scot C. R.; Michaels, Timothy I.

    2006-12-01

    The Viking Orbiters imaged early morning, long, linear wave clouds along the flanks of the Tharsis volcanoes during late northern spring and early summer. These clouds are believed to be a product of either an atmospheric bore wave or a hydraulic jump generated by nightly katabatic winds. The Mars Regional Atmospheric Modeling System was used to study the interaction of the katabatic flows with the surrounding atmosphere to determine what mechanism is responsible for the clouds. Simulations at L=90°, 100°, 142°, 180°, 270°, and 358° were conducted focusing on the eastern flank of Olympus Mons. Model results compare well with Viking observations and closely approximate theoretical treatments of atmospheric bores. Strong downslope flows are simulated during the night, with a bore wave forming on and behind a well-defined katabatic front. The observed seasonality of the clouds was reproduced in the simulations; the bore was deeper and faster during northern summer and weakest during the winter. When the bore was strong, it was undular in form, and generated vertically propagating gravity waves in the atmosphere above. During the winter, the atmospheric structure was such that any gravity waves generated damped with height. Less atmospheric water vapor abundance during northern winter, as compared to the summer, is also a factor in the seasonality of the wave clouds. This study concludes that bore waves are the most likely mechanism for the generation of the observed linear wave clouds.

  8. 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.

  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. The evolution of large-scale magnetic fields in the ionosphere of Venus

    NASA Technical Reports Server (NTRS)

    Cravens, T. E.; Shinagawa, H.; Nagy, A. F.

    1984-01-01

    Large-scale magnetic fields are often observed in the ionosphere of Venus by the magnetometer on the Pioneer Venus Orbiter, especially near the subsolar point or when the solar wind dynamic pressure is high. An equation for the time evolution of the magnetic field is derived which includes both a term representing the time rate of change of the field due to the convection of magnetic flux by plasma motions, and a magnetic diffusion/dissipation term. The ionospheric plasma velocities required by these equations were obtained by numerically solving the momentum equation. Numerical solutions to the magnetic field equation indicate that large-scale magnetic fields, which are not being actively maintained, decay with time scales ranging from tens of minutes to several hours. The vertical convection of magnetic flux enables magnetic field structures deep within the ionosphere to persist longer than would otherwise be expected. This vertical convection also explains the shape of these structures.

  11. 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.

  12. 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

  13. Reverse circulation air drilling can reduce well bore damage

    SciTech Connect

    Graham, R.L.; Foster, J.M.; Amick, P.C.; Shaw, J.S. )

    1993-03-22

    Reverse circulation air drilling coupled with an air dryer at the surface helped eliminate formation damage in several gas wells. During reverse circulation drilling, the air flows down the annulus and up the drill pipe. The following were the three primary objectives of damage-free drilling (DFD): Reducing damage so the initial open flows would more accurately reflect natural permeability. Reducing damage for diagnostic tools (temperature logs, noise logs, mud [gas composition] logs, and borehole television) to better detect liquid and gas entry points. Improving sampling by returning larger cuttings with shorter and more precise lag times. The secondary objectives were to reduce drilling costs through the following: Lowering required circulating air volumes when cuttings are reversed up the drillstring. Reducing water influx from shallow water zones because of annular back pressure during circulation. Improving penetration rates for larger holes. This describes tests while drilling; the borehole television used in investigating air-drilled well bores; permeability tests; cuttings sample; drilling parameters; and operations and results from two field tests.

  14. 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.

  15. 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.

  16. Large stable deformation of dielectric elastomers driven on mode of steady electric field

    NASA Astrophysics Data System (ADS)

    Zhang, Junshi; Zhao, Jianwen; Wang, Shu; Chen, Hualing; Li, Dichen

    2017-05-01

    Dielectric elastomers (DEs) are capable of large deformation under the actuation of applied voltage and sprayed charge. Actuation of DE under voltage control is prone to electromechanical instabilities, while the DE under charge control always survives from instabilities with sacrificing a large deformation. In this article, a novel actuation mode of steady electric field is proposed. By tuning applied voltage and sprayed charge during viscoelastic creep, an invariable electric field is generated. Such an actuation method can both avoid the occurrence of electromechanical instabilities and guarantee a large deformation in DE actuation.

  17. Thermally induced switching field distribution of a single CoPt dot in a large array

    NASA Astrophysics Data System (ADS)

    Engelen, J. B. C.; Delalande, M.; le Fèbre, A. J.; Bolhuis, T.; Shimatsu, T.; Kikuchi, N.; Abelmann, L.; Lodder, J. C.

    2010-01-01

    Magnetic dot arrays with perpendicular magnetic anisotropy were fabricated by patterning Co80Pt20-alloy continuous films by means of laser interference lithography. As commonly seen in large dot arrays, there is a large difference in the switching field between dots. Here we investigate the origin of this large switching field distribution, by using the anomalous Hall effect (AHE). The high sensitivity of the AHE permits us to measure the magnetic reversal of individual dots in an array of 80 dots with a diameter of 180 nm. By taking 1000 hysteresis loops we reveal the thermally induced switching field distribution SFDT of individual dots inside the array. The SFDT of the first and last switching dots were fitted to an Arrhenius model, and a clear difference in switching volume and magnetic anisotropy was observed between dots switching at low and high fields.

  18. Evolution of the large-scale tail of primordial magnetic fields

    SciTech Connect

    Jedamzik, Karsten; Sigl, Guenter

    2011-05-15

    Cosmic magnetic fields may be generated during early cosmic phase transition, such as the QCD or electroweak transitions. The magnitude of the remainder of such fields at the present epoch crucially depends on the exponent n of their (initially super-Hubble) large-scale tail, i.e., B{sub {lambda}{approx}{lambda}}{sup -n}. It has been claimed that causality requires n=5/2, contrary to much earlier claims of n=3/2. Here we analyze this question in detail. First, we note that contrary to current belief, the large-scale magnetic field tail is not established at the phase transition itself, but rather continuously evolves up to the present epoch. Neglecting turbulent flows we find n=7/2, i.e., very strongly suppressed large-scale fields. However, in the inevitable presence of turbulent flows we find that the large-scale magnetic field tail has sufficient time to evolve to that of the fluid turbulence. For white noise fluid turbulence this yields n=3/2 up to a certain scale and n=5/2 beyond for the magnetic field spectrum. This picture is also not changed when primordial viscosity and fluid flow dissipation is taken into account. Appreciable primordial magnetic fields originating from cosmic phase transitions thus seem possible.

  19. 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).

  20. 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.

  1. 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.

  2. 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.

  3. 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°.

  4. 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.

  5. 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.

  6. 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).

  7. 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).

  8. 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.

  9. 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

  10. 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.

  11. Fringe fields of current dominated multipole magnets

    SciTech Connect

    Wadlinger, E.A.

    1988-01-01

    We determine analytic functions that describe the fringe field region of Lambertson, or cosine-wound, magnets. In particular, we are interested in determining the aberrations, up to fifth order, of a beam transiting our large-bore current-dominated quadrupoles. We determine the scalar potential from the vector potential calculated first for a single current loop and then for a 2N symmetric current loop multipole magnet. 2 refs., 1 fig.

  12. Incident wave, infragravity wave, and non-linear low-frequency bore evolution across fringing coral reefs

    NASA Astrophysics Data System (ADS)

    Storlazzi, C. D.; Griffioen, D.; Cheriton, O. M.

    2016-12-01

    Coral reefs have been shown to significantly attenuate incident wave energy and thus provide protection for 100s of millions of people globally. To better constrain wave dynamics and wave-driven water levels over fringing coral reefs, a 4-month deployment of wave and tide gauges was conducted across two shore-normal transects on Roi-Namur Island and two transects on Kwajalein Island in the Republic of the Marshall Islands. At all locations, although incident wave (periods <25 s) heights were an order of magnitude greater than infragravity wave (periods > 250 s) heights on the outer reef flat just inshore of the zone of wave breaking, the infragravity wave heights generally equaled the incident wave heights by the middle of the reef flat and exceeded the incident wave heights on the inner reef flat by the shoreline. The infragravity waves generally were asymmetric, positively skewed, bore-like forms with incident-band waves riding the infragravity wave crest at the head of the bore; these wave packets have similar structure to high-frequency internal waves on an internal wave bore. Bore height was shown to scale with water depth, offshore wave height, and offshore wave period. For a given tidal elevation, with increasing offshore wave heights, such bores occurred more frequently on the middle reef flat, whereas they occurred less frequently on the inner reef flat. Skewed, asymmetric waves are known to drive large gradients in velocity and shear stress that can transport material onshore. Thus, a better understanding of these low-frequency, energetic bores on reef flats is critical to forecasting how coral reef-lined coasts may respond to sea-level rise and climate change.

  13. 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

  14. 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.

  15. 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.

  16. Low-Field-Triggered Large Magnetostriction in Iron-Palladium Strain Glass Alloys

    NASA Astrophysics Data System (ADS)

    Ren, Shuai; Xue, Dezhen; Ji, Yuanchao; Liu, Xiaolian; Yang, Sen; Ren, Xiaobing

    2017-09-01

    Development of miniaturized magnetostriction-associated devices requires low-field-triggered large magnetostriction. In this study, we acquired a large magnetostriction (800 ppm) triggered by a low saturation field (0.8 kOe) in iron-palladium (Fe-Pd) alloys. Magnetostriction enhancement jumping from 340 to 800 ppm was obtained with a slight increase in Pd concentration from 31.3 to 32.3 at. %. Further analysis showed that such a slight increase led to suppression of the long-range ordered martensitic phase and resulted in a frozen short-range ordered strain glass state. This strain glass state possessed a two-phase nanostructure with nanosized frozen strain domains embedded in the austenite matrix, which was responsible for the unique magnetostriction behavior. Our study provides a way to design novel magnetostrictive materials with low-field-triggered large magnetostriction.

  17. 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.

  18. 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.

  19. Evidence of mesospheric bore formation from a breaking gravity wave event: simultaneous imaging and lidar measurements

    NASA Astrophysics Data System (ADS)

    Smith, S. M.; Friedman, J.; Raizada, S.; Tepley, C.; Baumgardner, J.; Mendillo, M.

    2005-03-01

    A large wave event was observed in the three upper-mesospheric (80 105 km) airglow emissions of O(1S), Na and OH by the Boston University all-sky imager, at the Arecibo Observatory, during the night of 3 May 2003. The airglow structures appeared to be due to a large upward propagating internal gravity wave, which subsequently became unstable near the 95 km height level and produced large-scale vertical motions and mixing. Simultaneous density and temperature lidar measurements indicated the presence of a large temperature inversion of 80 K valley-to-peak between 88 and 96 km during the time of the event. Near-simultaneous temperature profiles, made by the TIMED SABER instrument, provided evidence that the horizontal extent of the inversion was localized to within 500 km of Arecibo during the wave event. As the gravity wave dissipated, an internal bore was generated, apparently due to the deposition of momentum and energy into the region by the original wave. Although mesospheric gravity wave breaking has been reported previously (Swenson and Mende, 21(1994); Hecht et al., 102(1997); Yamada et al., 28(2001), for example), this was the first time that the phenomenon has been associated with the generation of an internal mesospheric bore. The event suggested that the breaking of a large mesospheric gravity wave can lead to the generation of an internal bore, as suggested by Dewan and Picard 106(2001). Such behavior is of particular interest since little is known of their origins.

  20. Gauge-invariant perturbations at second order: multiple scalar fields on large scales

    NASA Astrophysics Data System (ADS)

    Malik, Karim A.

    2005-11-01

    We derive the governing equations for multiple scalar fields minimally coupled to gravity in a flat Friedmann Robertson Walker background spacetime on large scales. We include scalar perturbations up to second order and write the equations in terms of physically transparent gauge-invariant variables at first and second order. This allows us to write the perturbed Klein Gordon equation at second order solely in terms of the field fluctuations on flat slices at first and second order.

  1. Large-Scale Dynamics of Mean-Field Games Driven by Local Nash Equilibria

    NASA Astrophysics Data System (ADS)

    Degond, Pierre; Liu, Jian-Guo; Ringhofer, Christian

    2014-02-01

    We introduce a new mean field kinetic model for systems of rational agents interacting in a game-theoretical framework. This model is inspired from non-cooperative anonymous games with a continuum of players and Mean-Field Games. The large time behavior of the system is given by a macroscopic closure with a Nash equilibrium serving as the local thermodynamic equilibrium. An application of the presented theory to a social model (herding behavior) is discussed.

  2. 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.

  3. Spin-torque oscillation in large size nano-magnet with perpendicular magnetic fields

    NASA Astrophysics Data System (ADS)

    Luo, Linqiang; Kabir, Mehdi; Dao, Nam; Kittiwatanakul, Salinporn; Cyberey, Michael; Wolf, Stuart A.; Stan, Mircea; Lu, Jiwei

    2017-06-01

    DC current induced magnetization reversal and magnetization oscillation was observed in 500 nm large size Co90Fe10/Cu/Ni80Fe20 pillars. A perpendicular external field enhanced the coercive field separation between the reference layer (Co90Fe10) and free layer (Ni80Fe20) in the pseudo spin valve, allowing a large window of external magnetic field for exploring the free-layer reversal. A magnetic hybrid structure was achieved for the study of spin torque oscillation by applying a perpendicular field >3 kOe. The magnetization precession was manifested in terms of the multiple peaks on the differential resistance curves. Depending on the bias current and applied field, the regions of magnetic switching and magnetization precession on a dynamical stability diagram has been discussed in details. Micromagnetic simulations are shown to be in good agreement with experimental results and provide insight for synchronization of inhomogeneities in large sized device. The ability to manipulate spin-dynamics on large size devices could be proved useful for increasing the output power of the spin-transfer nano-oscillators (STNOs).

  4. 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.

  5. The Large Scale Structure of the Galactic Magnetic Field and High Energy Cosmic Ray Anisotropy

    NASA Astrophysics Data System (ADS)

    Alvarez-Muñiz, Jaime; Stanev, Todor

    2006-10-01

    Measurements of the magnetic field in our Galaxy are complex and usually difficult to interpret. A spiral regular field in the disk is favored by observations, however the number of field reversals is still under debate. Measurements of the parity of the field across the Galactic plane are also very difficult due to the presence of the disk field itself. In this work we demonstrate that cosmic ray protons in the energy range 1018 to 1019eV, if accelerated near the center of the Galaxy, are sensitive to the large scale structure of the Galactic Magnetic Field (GMF). In particular if the field is of even parity, and the spiral field is bi-symmetric (BSS), ultra high energy protons will predominantly come from the Southern Galactic hemisphere, and predominantly from the Northern Galactic hemisphere if the field is of even parity and axi-symmetric (ASS). There is no sensitivity to the BSS or ASS configurations if the field is of odd parity.

  6. High-latitude convection patterns for various large-scale field-aligned current configurations

    SciTech Connect

    Blomberg, L.G.; Marklund, G.T. )

    1991-04-01

    The large-scale field-aligned current system for persistent northward interplanetary magnetic field (IMF) is typically different from that for persistent southward IMF. One characteristic difference is that for northward IMF there is often a large-scale field-aligned current system poleward of the main auroral oval. This current system (the NBZ current) typically occupies a large function of the region poleward of the region 1 and 2 currents. The present paper models the high-latitude convection as a function of the large-scale field-aligned currents. In particular, a possible evolution of the convection pattern as the current system changes from a typical configuration for southward IMF to a configuration representing northward IMF (or vice versa) is presented. Depending on additional assumptions, for example about the y-component of the IMF, the convection pattern could either turn directly from a two-cell type to a four-cell type, or a three-cell type pattern could show up as an intermediate state. An interesting although rather surprising result of this study is that different ways of balancing the NBZ currents has a minor influence on the large-scale convection pattern.

  7. Design of a mobile, homogeneous, and efficient electromagnet with a large field of view for neonatal low-field MRI.

    PubMed

    Lother, Steffen; Schiff, Steven J; Neuberger, Thomas; Jakob, Peter M; Fidler, Florian

    2016-08-01

    In this work, a prototype of an effective electromagnet with a field-of-view (FoV) of 140 mm for neonatal head imaging is presented. The efficient implementation succeeded by exploiting the use of steel plates as a housing system. We achieved a compromise between large sample volumes, high homogeneity, high B0 field, low power consumption, light weight, simple fabrication, and conserved mobility without the necessity of a dedicated water cooling system. The entire magnetic resonance imaging (MRI) system (electromagnet, gradient system, transmit/receive coil, control system) is introduced and its unique features discussed. Furthermore, simulations using a numerical optimization algorithm for magnet and gradient system are presented. Functionality and quality of this low-field scanner operating at 23 mT (generated with 500 W) is illustrated using spin-echo imaging (in-plane resolution 1.6 mm × 1.6 mm, slice thickness 5 mm, and signal-to-noise ratio (SNR) of 23 with a acquisition time of 29 min). B0 field-mapping measurements are presented to characterize the homogeneity of the magnet, and the B0 field limitations of 80 mT of the system are fully discussed. The cryogen-free system presented here demonstrates that this electromagnet with a ferromagnetic housing can be optimized for MRI with an enhanced and homogeneous magnetic field. It offers an alternative to prepolarized MRI designs in both readout field strength and power use. There are multiple indications for the clinical medical application of such low-field devices.

  8. 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.

  9. Optimization of passive vibration absorbers to reduce chatter in boring

    NASA Astrophysics Data System (ADS)

    Rubio, L.; Loya, J. A.; Miguélez, M. H.; Fernández-Sáez, J.

    2013-12-01

    This paper is focused on the optimal selection of the parameters of a passive dynamic vibration absorber (DVA) attached to a boring bar. The boring bar was modeled as an Euler-Bernoulli cantilever beam and the stability of the system was analyzed in terms of the bar and the absorber characteristics. To obtain the optimum parameters of the absorber, a classical method for unconstrained optimization problems has been used. The selection criterion consisted of the maximization of the minimum values of the stability lobe diagram. Empirically fitted expressions for the frequency and damping ratio of the DVA (which permit to obtain its stiffness and damping) are proposed. These expressions are fully applicable when the damping ratio of the boring bar is non-null as it is in practical operations. The computed results show a clear improvement in the stability performance regarding other methodologies previously used.

  10. Optical method for inspecting surface defects inside a small bore

    NASA Astrophysics Data System (ADS)

    Hong, En; Katz, Reuven; Hufnagel, Brian; Agapiou, John

    2010-01-01

    Most automotive powertrain parts made of castings have surface defects such as pores. However, detecting pores inside small diameter bores is a challenge because of the limited dimensional accessibility. Adding to this difficulty is the auto industry's desire to conduct the porosity inspection in-line, i.e. within the machining production cycle time of a part. A technique or equipment that meets these requirements currently does not exist. In order to meet these demands, it is necessary to develop an entire new methodology to inspect the inner surface of small diameter bores. This paper presents an innovative methodology to inspect the porosity of the inner surface of small bores and to provide their characteristics such as size and location. A prototype measurement system was built and tested in the lab. Experimental results showed the proposed method to be reliable and consistent.

  11. 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.

  12. The mobility minima in pulsed-field capillary electrophoresis of large DNA.

    PubMed Central

    Sudor, J; Novotny, M

    1995-01-01

    Pulsed-field capillary electrophoresis represents a new tool for rapid and highly efficient separations of large biopolymers. The method has been utilized here to study dependencies of the electrophoretic mobility upon the frequency and pulse shape of applied voltage for large, double-stranded DNA molecules (5-100 kb) migrating in neutral polymer solutions. Two different shapes of alternating electric field (sine- and square-wave impulses) were examined with the frequency values ranging from 1 to 30 Hz. The linear dependence between duration of the forward pulse (at which the DNA molecule experiences a minimum mobility) and the product N.In(N) (where N is the number of base pairs) was experienced in field-inversion gel electrophoresis, while exponential dependence was found with the sinusoidal electric field. The mobility minima were lower in field-inversion electrophoresis than with the biased sinusoidal-field technique. The DNA (5 kb concatamers) was adequately separated using a ramp of frequency in the square-wave electric field, in approximately 1 h. The migration order of DNA fragments was referenced through adding a monodisperse DNA (48.5 kb) into the sample. The band inversion phenomena were not observed under any experimental conditions used in this work. PMID:7630733

  13. Simulating large scale structure with lognormal fields: a new code and approach

    NASA Astrophysics Data System (ADS)

    Xavier, H. S.; Abdalla, F. B.; Joachimi, B.

    2017-07-01

    It is common practice in cosmology to use lognormal random fields to model large-scale structure observables such as matter density and weak lensing convergence. I will present the public code Full-sky Lognormal Astro-fields Simulation Kit (FLASK) which can make tomographic realizations on spherical shells around the observer of an arbitrary number of correlated lognormal or Gaussian random fields, including the Cosmic Microwave Background (CMB) and multiple tracers of matter. I will show that lognormal fields have fundamental limitations which prevent its use for jointly modelling density and convergence and will propose two ways of overcoming these limitations. The first approach slightly distorts the power spectra of the fields while the second one generates a different weak lensing convergence marginal distribution by integrating the lognormal density along the line of sight. The latter approach also provides a way to determine directly from theory the skewness of the convergence distribution and, therefore, the parameters for a lognormal fit.

  14. 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.

  15. 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.

  16. 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.

  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. 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

  19. Continuous measurements of in-bore projectile velocity

    SciTech Connect

    Asay, J.R.; Konrad, C.H.; Hall, C.A. ); Shahinpoor, M. . Dept. of Mechanical Engineering); Hickman, R. )

    1989-01-01

    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.

  20. 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.

  1. 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.

  2. 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

  3. 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.

  4. 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...

  5. 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...

  6. 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.

  7. The spin density wave state in (TMTSF)2X under large electric and magnetic fields

    NASA Astrophysics Data System (ADS)

    Leone, Michael J.

    We have developed a technique to study the conductivity of materials in the limit of large electric fields. The materials that this study focused on are susceptible to damage due to Joule heating in large DC currents. This technique allows the application of electric fields as large as several hundred volts/cm without sample destruction. The duration of the applied current pulses is user selectable and ranges from 10 mus to several hundred seconds. Measurements were conducted with square pulses of duration 300 mus. We have applied this technique to the study of the family of compounds known as the Bechgaard salts ((TMTSF)2X). The material (TMTSF)2PF6 at ambient pressure exhibits metallic behavior above 12 K. Below 12 K the material enters an insulating caused by the formation of a spin density wave (SDW). Below 12 K, it has been observed that the application of small electric fields causes an increase in the conductivity. We have observed that these materials exhibit negative differential resistance when subjected to large electric fields. We have shown that the observed effects are due to self heating of the sample.

  8. 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.

  9. 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...

  10. 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...

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Effect of primordial magnetic field on seeds for large scale structure

    SciTech Connect

    Yamazaki, Dai Great; Hanayama, Hidekazu; Ichiki, Kiyotomo; Umezu, Ken-ichi

    2006-12-15

    Magnetic field plays a very important role in many astronomical phenomena at various scales of the universe. It is no exception in the early universe. Since the energy density, pressure, and tension of the primordial magnetic field affect gravitational collapses of plasma, the formation of seeds for large-scale structures should be influenced by them. Here we numerically investigate the effects of stochastic primordial magnetic field on the seeds of large-scale structures in the universe in detail. We found that the amplitude ratio between the density spectra with and without PMF (vertical bar P(k)/P{sub 0}(k) vertical bar at k>0.2 Mpc{sup -1}) lies between 75% and 130% at present for the range of PMF strengths 0.5nG

  16. Large-scale solar magnetic fields and H-alpha patterns

    NASA Technical Reports Server (NTRS)

    Mcintosh, P. S.

    1972-01-01

    Coronal and interplanetary magnetic fields computed from measurements of large-scale photospheric magnetic fields suffer from interruptions in day-to-day observations and the limitation of using only measurements made near the solar central meridian. Procedures were devised for inferring the lines of polarity reversal from H-alpha solar patrol photographs that map the same large-scale features found on Mt. Wilson magnetograms. These features may be monitored without interruption by combining observations from the global network of observatories associated with NOAA's Space Environment Services Center. The patterns of inferred magnetic fields may be followed accurately as far as 60 deg from central meridian. Such patterns will be used to improve predictions of coronal features during the next solar eclipse.

  17. 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.

  18. 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.

  19. Background-oriented schlieren for the study of large flow fields

    NASA Astrophysics Data System (ADS)

    Trolinger, James D.; Buckner, Ben; L'Esperance, Drew

    2015-09-01

    Modern digital recording and processing techniques combined with new lighting methods and relatively old schlieren visualization methods move flow visualization to a new level, enabling a wide range of new applications and a possible revolution in the visualization of very large flow fields. This paper traces the evolution of schlieren imaging from Robert Hooke, who, in 1665, employed candles and lenses, to modern digital background oriented schlieren (BOS) systems, wherein image processing by computer replaces pure optical image processing. New possibilities and potential applications that could benefit from such a capability are examined. Example applications include viewing the flow field around full sized aircraft, large equipment and vehicles, monitoring explosions on bomb ranges, cooling systems, large structures and even buildings. Objectives of studies include aerodynamics, aero optics, heat transfer, and aero thermal measurements. Relevant digital cameras, light sources, and implementation methods are discussed.

  20. 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.

  1. 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.

  2. Not a load of rubbish: simulated field trials in large-scale containers.

    PubMed

    Hohmann, M; Stahl, A; Rudloff, J; Wittkop, B; Snowdon, R J

    2016-09-01

    Assessment of yield performance under fluctuating environmental conditions is a major aim of crop breeders. Unfortunately, results from controlled-environment evaluations of complex agronomic traits rarely translate to field performance. A major cause is that crops grown over their complete lifecycle in a greenhouse or growth chamber are generally constricted in their root growth, which influences their response to important abiotic constraints like water or nutrient availability. To overcome this poor transferability, we established a plant growth system comprising large refuse containers (120 L 'wheelie bins') that allow detailed phenotyping of small field-crop populations under semi-controlled growth conditions. Diverse winter oilseed rape cultivars were grown at field densities throughout the crop lifecycle, in different experiments over 2 years, to compare seed yields from individual containers to plot yields from multi-environment field trials. We found that we were able to predict yields in the field with high accuracy from container-grown plants. The container system proved suitable for detailed studies of stress response physiology and performance in pre-breeding populations. Investment in automated large-container systems may help breeders improve field transferability of greenhouse experiments, enabling screening of pre-breeding materials for abiotic stress response traits with a positive influence on yield. © 2016 John Wiley & Sons Ltd.

  3. Load-balanced parallel streamline generation on large scale vector fields.

    PubMed

    Nouanesengsy, Boonthanome; Lee, Teng-Yok; Shen, Han-Wei

    2011-12-01

    Because of the ever increasing size of output data from scientific simulations, supercomputers are increasingly relied upon to generate visualizations. One use of supercomputers is to generate field lines from large scale flow fields. When generating field lines in parallel, the vector field is generally decomposed into blocks, which are then assigned to processors. Since various regions of the vector field can have different flow complexity, processors will require varying amounts of computation time to trace their particles, causing load imbalance, and thus limiting the performance speedup. To achieve load-balanced streamline generation, we propose a workload-aware partitioning algorithm to decompose the vector field into partitions with near equal workloads. Since actual workloads are unknown beforehand, we propose a workload estimation algorithm to predict the workload in the local vector field. A graph-based representation of the vector field is employed to generate these estimates. Once the workloads have been estimated, our partitioning algorithm is hierarchically applied to distribute the workload to all partitions. We examine the performance of our workload estimation and workload-aware partitioning algorithm in several timings studies, which demonstrates that by employing these methods, better scalability can be achieved with little overhead. © 2011 IEEE

  4. 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.

  5. 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.

  6. Large-volume lava flow fields on Venus: Dimensions and morphology

    NASA Technical Reports Server (NTRS)

    Lancaster, M. G.; Guest, J. E.; Roberts, K. M.; Head, James W., III

    1992-01-01

    Of all the volcanic features identified in Magellan images, by far the most extensive and really important are lava flow fields. Neglecting the widespread lava plains themselves, practically every C1-MIDR produced so far contains several or many discrete lava flow fields. These range in size from a few hundred square kilometers in area (like those fields associated with small volcanic edifices for example), through all sizes up to several hundred thousand square kilometers in extent (such as many rift related fields). Most of these are related to small, intermediate, or large-scale volcanic edifices, coronae, arachnoids, calderas, fields of small shields, and rift zones. An initial survey of 40 well-defined flow fields with areas greater than 50,000 sq km (an arbitrary bound) has been undertaken. Following Columbia River Basalt terminology, these have been termed great flow fields. This represents a working set of flow fields, chosen to cover a variety of morphologies, sources, locations, and characteristics. The initial survey is intended to highlight representative flow fields, and does not represent a statistical set. For each flow field, the location, total area, flow length, flow widths, estimated flow thicknesses, estimated volumes, topographic slope, altitude, backscatter, emissivity, morphology, and source has been noted. The flow fields range from about 50,000 sq km to over 2,500,000 sq km in area, with most being several hundred square kilometers in extent. Flow lengths measure between 140 and 2840 km, with the majority of flows being several hundred kilometers long. A few basic morphological types have been identified.

  7. 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.

  8. 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.

  9. One-loop Pfaffians and large-field inflation in string theory

    NASA Astrophysics Data System (ADS)

    Ruehle, Fabian; Wieck, Clemens

    2017-06-01

    We study the consistency of large-field inflation in low-energy effective field theories of string theory. In particular, we focus on the stability of Kähler moduli in the particularly interesting case where the non-perturbative superpotential of the Kähler sector explicitly depends on the inflaton field. This situation arises generically due to one-loop corrections to the instanton action. The field dependence of the modulus potential feeds back into the inflationary dynamics, potentially impairing slow roll. We distinguish between world-sheet instantons from Euclidean D-branes, which typically yield polynomial one-loop Pfaffians, and gaugino condensates, which can yield exponential or periodic corrections. In all scenarios successful slow-roll inflation imposes bounds on the magnitude of the one-loop correction, corresponding to constraints on possible compactifications. While we put a certain emphasis on Type IIB constructions with mobile D7-branes, our results seem to apply more generally.

  10. 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.

  11. Classifying Large-Amplitude Parallel Electric Fields Along the Magnetopause and Their Effect on Magnetic Reconnection

    NASA Astrophysics Data System (ADS)

    Goodrich, K.; Ergun, R.; Wilder, F. D.; Holmes, J.; Khotyaintsev, Y. V.; Lindqvist, P. A.; Burch, J. L.; Gershman, D. J.; Giles, B. L.; Le Contel, O.; Strangeway, R. J.; Russell, C.; Torbert, R. B.

    2016-12-01

    During the first year of the Magnetospheric Multiscale Mission (MMS) there have been multiple observations of large amplitude parallel electric fields, as high as 100 mV/m, associated with magnetic reconnection along the terrestrial magnetopause. These electric fields have been observed as a variety of different wave phenomena and plasma structures. One distinct and rare type of plasma structures are unipolar, high amplitude, parallel electric field pulses which are observed directly adjacent to the electron diffusion region and are thought to represent secondary reconnection. Intense parallel plasma waves are interpreted to be ion acoustic waves, electron acoustic waves or beam mode, indicative of cold plasma mixing. Nonlinear structures commonly associated with Alfvénic turbulence on the magnetospheric side of the magnetopause are also reported. We present examples of these three parallel electric field signatures and examine their possible implications on magnetic reconnection.

  12. Magnetospheric Multiscale Observations of the Electron Diffusion Region of Large Guide Field Magnetic Reconnection

    NASA Technical Reports Server (NTRS)

    Eriksson, S.; Wilder, F. D.; Ergun, R. E.; Schwartz, S. J.; Cassak, P. A.; Burch, J. L.; Chen, Li-Jen; Torbert, R. B.; Phan, T. D.; Lavraud, B.; hide

    2016-01-01

    We report observations from the Magnetospheric Multiscale (MMS) satellites of a large guide field magnetic reconnection event. The observations suggest that two of the four MMS spacecraft sampled the electron diffusion region, whereas the other two spacecraft detected the exhaust jet from the event. The guide magnetic field amplitude is approximately 4 times that of the reconnecting field. The event is accompanied by a significant parallel electric field (E(sub parallel lines) that is larger than predicted by simulations. The high-speed (approximately 300 km/s) crossing of the electron diffusion region limited the data set to one complete electron distribution inside of the electron diffusion region, which shows significant parallel heating. The data suggest that E(sub parallel lines) is balanced by a combination of electron inertia and a parallel gradient of the gyrotropic electron pressure.

  13. Large magnetostrain in magnetic-field-aligned Mn0.965CoGe compound

    NASA Astrophysics Data System (ADS)

    Hu, Qiu-Bo; Hu, Yong; Fang, Yong; Wang, Dun-Hui; Cao, Qing-Qi; Yang, Yan-Ting; Li, Jing; Du, You-Wei

    2017-05-01

    By applying external stimulus (temperature or magnetic field), MnCoGe-based compounds undergo a martensitic transformation from hexagonal Ni2In-type to orthorhombic TiNiSi-type structure accompanied with a giant negative thermal expansion, which suggests a large magnetic-field-induced strain. However, these compounds naturally collapse into powders and are difficult to be oriented, which hinder their applications for magnetostrain. In this paper, a magnetic-field-aligned Mn0.965CoGe compound was prepared by bonding with epoxy resin and orientating in a magnetic field. The XRD patterns revealed the texture in this sample. By introducing vacancies of Mn element, the magnetostructural transformation temperature of Mn0.965CoGe compound was shifted down to 278 K. The magnetostrain was measured at some selected temperatures and the maximal strain could reach up to 925 ppm at 270 K.

  14. 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.

  15. 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.

  16. 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

  17. Artificial rearing of 10 species of wood-boring insects

    Treesearch

    Jimmy R. Galford

    1969-01-01

    Small numbers of 10 species of wood-boring insects were reared from newly hatched larvae to adults on artificial media with good survival. Species with life cycles of up to 2 years in nature were reared on the media in less than 1 year. Although all of the adults appeared normal physically, some were sterile. One species was reared artificially for three generations....

  18. 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…

  19. 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

  20. 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.

  1. Step-Controllable Electric-Field-Assisted Nanoimprint Lithography for Uneven Large-Area Substrates.

    PubMed

    Wang, Chunhui; Shao, Jinyou; Tian, Hongmiao; Li, Xiangming; Ding, Yucheng; Li, Ben Q

    2016-04-26

    Large-area nanostructures are widely used in various fields, but fabrication on large-area uneven substrates poses a significant challenge. This study demonstrates a step-controllable electric-field-assisted nanoimprint lithography (e-NIL) method that can achieve conformal contact with uneven substrates for high fidelity nanostructuring. Experiments are used to demonstrate the method where a substrate coated with liquid resist is brought into contact with a flexible template driven by the applied electric field. Theoretical analysis based on the elasticity theory and electro-hydrodynamic theory is carried out. Effective voltage range and the saturation voltage are also discussed. A step-controllable release of flexible template is proposed and demonstrated to ensure the continuous contact between the template and an uneven substrate. This prevents formation of air traps and allows large area conformal contact to be achieved. A combination of Vacuum-electric field assisted step-controllable e-NIL is implemented in the developed prototype. Finally, photonic crystal nanostructures are successfully fabricated on a 4 in., 158 μm bow gallium nitride light-emitting diode epitaxial wafer using the proposed method, which enhance the light extraction property.

  2. 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.

  3. 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

  4. Dual mean field search for large scale linear and quadratic knapsack problems

    NASA Astrophysics Data System (ADS)

    Banda, Juan; Velasco, Jonás; Berrones, Arturo

    2017-07-01

    An implementation of mean field annealing to deal with large scale linear and non linear binary optimization problems is given. Mean field annealing is based on the analogy between combinatorial optimization and interacting physical systems at thermal equilibrium. Specifically, a mean field approximation of the Boltzmann distribution given by a Lagrangian that encompass the objective function and the constraints is calculated. The original discrete task is in this way transformed into a continuous variational problem. In our version of mean field annealing, no temperature parameter is used, but a good starting point in the dual space is given by a ;thermodynamic limit; argument. The method is tested in linear and quadratic knapsack problems with sizes that are considerably larger than those used in previous studies of mean field annealing. Dual mean field annealing is capable to find high quality solutions in running times that are orders of magnitude shorter than state of the art algorithms. Moreover, as may be expected for a mean field theory, the solutions tend to be more accurate as the number of variables grow.

  5. A Method for Observing Soil Re-Deposition and Soil Loss Rates in Large Field Experiments

    NASA Astrophysics Data System (ADS)

    Hsieh, Y. P.; Bugna, G. C.; Nemours, D.

    2014-12-01

    The lack of quality soil erosion field data, which is required for the verification and calibration of soil erosion models, has been one of the serious problems in the soil conservation modeling today. Observing soil erosion of a relatively large field under truly unobstructed runoff conditions has rarely been done and doccumented. Report here is the results of our observation of soil erosion in a 7.3 ha peanut-cotton cropping system in the Mears Farm of Grand Ridge, FL. We used the mesh-pad method to quantify soil loss from the field and soil re-deposition in the field over the cropping season of 2010. The main slope (1-3 %) of the field is about 210 m long. We show that the amount of soil re-deposition was 50-150 times of the soil loss from the slope. The corresponding organic matter, nitrogen, phosphorous and silt and clay contents of the lost soil, however, were 20.9%, 21%, 17.6% and 14.2%, respectively, of the total amounts re-deposited on the slope. The amounts of soil loss predicted by a SWAT model was 10-20 times greater than our observed values. Soil erosion process was quite heterogeneous, as shown by the mesh-pad method, even on a seemingly uniform cultivated field. Soil erosion models need to be verified and calibrated by extensive quality field data in order to improve their performance.

  6. 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

  7. Effects of broken solenoidal condition of magnetic field in MHD simulation for large helical device plasmas

    NASA Astrophysics Data System (ADS)

    Takado, W.; Matsumoto, Y.; Watanabe, K. Y.; Tomioka, S.; Oikawa, S.

    2017-09-01

    We studied the effects of the broken solenoidal condition of a magnetic field in linear magnetohydrodynamics (MHD) simulations based on a real coordinate system for Large Helical Device plasmas. Artificial errors of various orders in this condition were introduced into linear MHD simulations and compared. Spurious Fourier modes were observed to be dominant because of the error in the condition. We suggested a criterion, which is expressed as the condition that the ratio of the error force to the Lorentz force is much smaller than 100%, for estimating an acceptable limit of the solenoidal condition error through the simulation results. The effects of a large error in the condition of the analysis of a specified single-mode instability were investigated in addition. Adding a large error in the condition resulted in certain undesirable modes becoming dominant, whereas the desirable mode did not dominate. Thus, a large error in the condition can be harmful to analysis with a focus on specified modes.

  8. 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.

  9. Influence of a large-scale field on energy dissipation in magnetohydrodynamic turbulence

    NASA Astrophysics Data System (ADS)

    Zhdankin, Vladimir; Boldyrev, Stanislav; Mason, Joanne

    2017-07-01

    In magnetohydrodynamic (MHD) turbulence, the large-scale magnetic field sets a preferred local direction for the small-scale dynamics, altering the statistics of turbulence from the isotropic case. This happens even in the absence of a total magnetic flux, since MHD turbulence forms randomly oriented large-scale domains of strong magnetic field. It is therefore customary to study small-scale magnetic plasma turbulence by assuming a strong background magnetic field relative to the turbulent fluctuations. This is done, for example, in reduced models of plasmas, such as reduced MHD, reduced-dimension kinetic models, gyrokinetics, etc., which make theoretical calculations easier and numerical computations cheaper. Recently, however, it has become clear that the turbulent energy dissipation is concentrated in the regions of strong magnetic field variations. A significant fraction of the energy dissipation may be localized in very small volumes corresponding to the boundaries between strongly magnetized domains. In these regions, the reduced models are not applicable. This has important implications for studies of particle heating and acceleration in magnetic plasma turbulence. The goal of this work is to systematically investigate the relationship between local magnetic field variations and magnetic energy dissipation, and to understand its implications for modelling energy dissipation in realistic turbulent plasmas.

  10. Mounting large lenses in wide-field instruments for the converted MMT

    NASA Astrophysics Data System (ADS)

    Fata, Robert G.; Fabricant, Daniel G.

    1998-07-01

    We describe the techniques that we have used to mount large optics in three wide-field instruments for the converted MMT: the wide-field corrector uses to provide a 1 degree diameter field at the f/5 focus of the converted MMT, the Hectospec bench spectrograph fed by 300 optical fibers and the wide- field dual-beam Binospec spectrograph. These optics are primarily refractive elements with diameters between 0.2 and 0.8 m that must be mounted from their edges, although we also describe mounts for two large mirrors in the Hectospec bench spectrograph. Both the wide-field corrector and Binospec mounts must perform under varying gravity loads: the corrector is fixed to the converted MMT's primary mirror cell and is tilted from zenith to horizon while Binospec is mounted at the converted MMT's Cassegrain focus. Furthermore, the optics mounts for both instruments must fit within tight space constraints. The Hectospec spectrograph is mounted in the MMT's rotating building and experiences a constant gravity vector. In all cases, the mounts must perform over a wide temperature range, -20 to 20 degrees Celsius, so the issue of differential thermal expansion between the mounts and optics must be carefully considered. As a result, the mounts we discuss include either RTV elastomeric or flexural elements.

  11. Ex vivo thermoacoustic imaging over large fields of view with 108 MHz irradiation.

    PubMed

    Eckhart, Andrew T; Balmer, Robert T; See, William A; Patch, S K

    2011-08-01

    Thermoacoustic signals are generated over a large field of view by 900 ns TE10 pulses with 108 MHz carrier frequency. Test specimens selectively absorb the TE10 pulse energy producing rapid thermal expansions that generate ultrasonic pulses. 108 MHz irradiation provides excellent depth penetration in soft tissue, allowing blood and physiologic saline to generate strong signals. Thermoacoustic signal generation from a depth of several cm is well above our systems noise floor. Rotating the test specimen provides single-slice tomographic signal encoding. Filtered back-projection reconstruction yields images over a 6.4 cm field of view. Reconstructions of tissue mimicking prostate phantoms and fresh porcine kidney tissue are presented.

  12. 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.

  13. 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.

  14. Nonlinear excitations of blood flow in large vessels under thermal radiations and uniform magnetic field

    NASA Astrophysics Data System (ADS)

    Tabi, C. B.; Motsumi, T. G.; Bansi Kamdem, C. D.; Mohamadou, A.

    2017-08-01

    A nonlinear model of blood flow in large vessels is addressed. The influence of radiations, viscosity and uniform magnetic fields on velocity and temperature distribution waveforms is studied. Exact solutions for the studied model are investigated through the F - expansion method. Based on the choice of parameter values, single-, multi-soliton and Jacobi elliptic function solutions are obtained. Viscosity and permanent magnetic field bring about wave spreading and reduce the velocity of blood, while radiations have reversed effects with strong impact on the waveform frequency of both the velocity and temperature distribution.

  15. 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.

  16. 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.

  17. 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.

  18. Undular bores in the presence of a vertically sheared current

    NASA Astrophysics Data System (ADS)

    Kharif, Christian; Abid, Malek

    2017-04-01

    The evolution of two-dimensional undular bores travelling on a vertically sheared current of constant vorticity is investigated. Considering Euler equations, in the shallow water approximation, hyperbolic equations for the surface elevation and the horizontal velocity are derived. Using Riemann invariants of these equations, that are obtained analytically, a closed-form nonlinear evolution equation for the surface elevation is derived. A dispersive term is added to this equation using the fully linear dispersion relation. The heuristic introduction of dispersion allows the study of strongly nonlinear two-dimensional long gravity waves in the presence of constant vorticity. Within the framework of the model derived from Riemann invariants with the addition of dispersion we have considered the problem of non breaking undular bores. An undular bore is formed when a sudden discharge of water at rest of depth h(1+Δ) is initiated into a still water of depth h. To consider non-breaking undular bore, the initial relative difference in water level, Δ, is chosen less than 0.28. Favre (1935) showed experimentally that beyond this value undular bores evolve to breaking. To consider the effect of the vorticity on the height of the leading wave, hmax, we have run a series of numerical simulations. The height of the leading wave was recorded at 100 depths. For a fixed value of Δ, we found that negative vorticity amplifies, hmax whereas positive vorticity reduces the maximal height. This finding is in full agreement with the results of Touboul & Kharif (2016) who investigated the effect of vorticity on rogue waves due to dispersive focusing.

  19. 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. © 2016 Society of Chemical Industry.

  20. 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.

  1. 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

  2. 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

  3. Seeing asymptotic freedom in an exact correlator of a large-N matrix field theory

    NASA Astrophysics Data System (ADS)

    Orland, Peter

    2014-12-01

    Exact expressions for correlation functions are known for the large-N (planar) limit of the (1 +1 )-dimensional SU (N )×SU (N ) principal chiral sigma model. These were obtained with the form-factor bootstrap, an entirely nonperturbative method. The large-N solution of this asymptotically free model is far less trivial than that of the O (N ) sigma model (or other isovector models). Here we study the Euclidean two-point correlation function N-1⟨Tr Φ (0 )†Φ (x )⟩ , where Φ (x )˜Z-1 /2U (x ) is the scaling field and U (x )∈SU (N ) is the bare field. We express the two-point function in terms of the spectrum of the operator √{-d2/d u2 }, where u ∈(-1 ,1 ). At short distances, this expression perfectly matches the result from the perturbative renormalization group.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. The large-scale peculiar velocity field in flat models of the universe

    NASA Technical Reports Server (NTRS)

    Vittorio, Nicola; Turner, Michael S.

    1987-01-01

    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.

  9. Large-sized light field three-dimensional display using multi-projectors and directional diffuser

    NASA Astrophysics Data System (ADS)

    Peng, Yi-fan; Li, Hai-feng; Zhong, Qing; Xia, Xin-xing; Liu, Xu

    2013-01-01

    A scalable system to achieve large-sized light field three-dimensional display using multi-projectors and directional diffuser is presented. The system mainly employs an array of mini-projectors projecting images onto a special cylindrical directional diffuser screen. The principle of light field reconstruction, configuration of multi-projectors style, and characteristics of directional diffuser are explicitly analyzed, respectively. A prototype of a piece of equipment in mini-cinema class is proposed, with 100 mini-projectors and a special cylindrical directional diffuser performing different diffuse angles in horizontal and vertical directions. Bright and large-sized three-dimensional images displayed by the system can be observed at different horizontal viewing positions around the cylindrical display area with stereo parallax and motion parallax.

  10. 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.

  11. 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.

  12. 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.

  13. A Pilot for a Very Large Array H I Deep Field

    NASA Astrophysics Data System (ADS)

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

    2013-06-01

    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' × 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.

  14. 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.

  15. 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.

  16. [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.

  17. 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.

  18. 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.

  19. 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 shall...

  20. 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.

  1. 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...

  2. Long-term average non-dipole fields; how large or how small?

    NASA Astrophysics Data System (ADS)

    Van Der Voo, R.; Domeier, M. M.; Torsvik, T. H.

    2012-12-01

    Paul Louis Mercanton suggested already in the late 1920's that paleomagnetism might provide a test of continental drift. However, the absence of an adequate understanding of the ancient (!) geomagnetic field structure hampered such a test until some 25 years later. But then, the results of the paleomagnetic study of Neogene Icelandic lavas by Hospers in the early 1950's, provided a breakthrough. Two very important findings were: (1) that the field in the Neogene was predominantly dipolar, implying that higher-order fields (quadrupoles, octupoles) averaged to near-zero, and (2) that the dipole axis remained on average aligned with the rotation axis, during normal- as well as reversed-polarity fields intervals. The last conclusion prompted Creer, Irving, and Runcorn to remark that "The coincidence of the magnetic and rotation axes [ . . .] covering many reversals is explained by the dominance of the Coriolis force". The geocentric axial dipole (GAD) hypothesis remained ever after the main guiding principle of paleomagnetic analysis, allowing declination anomalies to be interpreted as rotations and inclinations as representative of paleolatitudes. It is generally agreed upon that the long-term averaged field structure is largely, but not perfectly, dipolar. The critical question about non-dipole fields is "how large" (or, perhaps, "how small"). Analysis of the magnitude of non-dipole fields is restricted to zonal fields of degree (n) two or three, i.e., axial quadrupole and octupole fields, characterized by Gaussian coefficient ratios (Gn) where G is the ratio of the appropriate higher-order field coefficient and the axial dipole field coefficient. For the last 5 million years G2 and G3 are small, but not zero (Johnson et al., 2008, G-cubed), and for earlier geological times (Permian, Triassic) some speculations by some of us have considered values up to 0.2, on the basis of inclination patterns. The underlying assumption that inclination anomalies were attributable

  3. 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.

  4. 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.

  5. Dense percolation in large-scale mean-field random networks is provably "explosive".

    PubMed

    Veremyev, Alexander; Boginski, Vladimir; Krokhmal, Pavlo A; Jeffcoat, David E

    2012-01-01

    Recent reports suggest that evolving large-scale networks exhibit "explosive percolation": a large fraction of nodes suddenly becomes connected when sufficiently many links have formed in a network. This phase transition has been shown to be continuous (second-order) for most random network formation processes, including classical mean-field random networks and their modifications. We study a related yet different phenomenon referred to as dense percolation, which occurs when a network is already connected, but a large group of nodes must be dense enough, i.e., have at least a certain minimum required percentage of possible links, to form a "highly connected" cluster. Such clusters have been considered in various contexts, including the recently introduced network modularity principle in biological networks. We prove that, contrary to the traditionally defined percolation transition, dense percolation transition is discontinuous (first-order) under the classical mean-field network formation process (with no modifications); therefore, there is not only quantitative, but also qualitative difference between regular and dense percolation transitions. Moreover, the size of the largest dense (highly connected) cluster in a mean-field random network is explicitly characterized by rigorously proven tight asymptotic bounds, which turn out to naturally extend the previously derived formula for the size of the largest clique (a cluster with all possible links) in such a network. We also briefly discuss possible implications of the obtained mathematical results on studying first-order phase transitions in real-world linked systems.

  6. Magnetic neutral lines of the large-scale magnetic field and solar activity

    SciTech Connect

    Makarov, V.I.; Tavastsherna, K.S.; Sivaraman, K.R.

    1986-06-01

    Two components in the size distribution of structures of the large-scale magnetic field are distinguished on the basis of H-alpha synoptic maps for the period 1955-1981. It is shown that the overall solar magnetic field has a latitudinal zonal structure, which is formed from elements of the first and second distributions. The boundaries of the latitude zones of the magnetic field oscillate about the mean latitudes or have only polar drift. Three types of quasiperiodic oscillations are noted, the periods of which differ in the S and N hemispheres. The most probable period of the oscillations (about 20 solar revolutions) is distinguished in the Southern Hemisphere. 14 references.

  7. 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.

  8. Pulsed-Field Electrophoresis: Application of a Computer Model to the Separation of Large DNA Molecules

    NASA Astrophysics Data System (ADS)

    Lalande, Marc; Noolandi, Jaan; Turmel, Chantal; Rousseau, Jean; Slater, Gary W.

    1987-11-01

    The biased reptation theory has been applied to the pulsed-field electrophoresis of DNA in agarose gels. A computer simulation of the theoretical model that calculates the mobility of large DNA molecules as a function of agarose pore size, DNA chain properties, and electric field conditions has been used to generate mobility curves for DNA molecules in the size range of the larger yeast chromosomes. Pulsed-field electrophoresis experiments resulting in the establishment of an electrophoretic karyotype for yeast, where the mobility of the DNA fragments is a monotonic function of molecular size for the entire size range that is resolved (200-2200 kilobase pairs), has been compared to the theoretical mobility curves generated by the computer model. The various physical mechanisms and experimental conditions responsible for band inversion and improved electrophoretic separation are identified and discussed in the framework of the model.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Control of field uniformity for a large superconducting storage ring magnet

    SciTech Connect

    Danby, G.T.; Jackson, J.W.

    1994-11-01

    A 1.45 Tesla, 14.2 meter diameter ``superferric`` magnet is in an advanced stage of construction at BNL. This magnet will be used to store muons for a planned ultra-precise measurement of their anomalous magnetic moment g-2. This measurement requires a magnetic field uniformity of 1 PPM with a knowledge of the field over the muon orbits to 0.1 PPM. The methods built into the design to produce ultra-high field uniformity will be described. Large deviations from the ideal circularly symmetric uniform shape of the iron flux path are required to accommodate transfer lines and superconducting current leads, as well as apparatus for beam injection. Shimming methods to correct for the perturbations due to these large holes will be presented. The pole pieces consist of 36 closely fitting 10{degree} arc sections butted together to produce a very good approximation to a continuous 360{degree} ring magnet. However, in the cast of a possible quench of the superconducting coils, significant eddy currents will be induced which will circulate within the confines of each 10{degree} pole piece. At the great precision required, these eddy currents may leave very small but significant aberrations in the field even after they decay away, because of slight changes in the orientation of the magnetization. Surface coil possibilities to correct for this effect will be described.

  15. 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.

  16. 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.

  17. 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.

  18. Fast-pressure field calculations applied to large spherical ultrasound phased arrays designed for thermal therapy

    NASA Astrophysics Data System (ADS)

    Zeng, Xiaozheng; Wu, Liyong; McGough, Robert J.

    2005-04-01

    Large spherical ultrasound phased arrays are ideal for simulation studies of thermal therapy devices designed for noninvasive breast cancer treatments. In a spherical array, circular sources packed in a dense hexagonal arrangement facilitate the most efficient use of the available aperture. Circular sources are also preferred for simulations of large phased arrays because pressure fields are computed more rapidly for circular pistons than for any other transducer geometry. The computation time is further reduced for circular transducers with grid sectoring. With this approach, the grid of computed pressures is divided into several regions, and then grid sectoring applies more abscissas in regions where the pressure integral converges slowly and fewer abscissas where the integral converges rapidly. As a result, the peak value of the numerical error is roughly the same in each sector, so the maximum numerical error in the computed field is maintained while the computation time is significantly reduced. The grid sectoring approach is extended to three dimensions (3D) for pressure field calculations with spherical arrays. In 3D calculations, the sectors are represented by cones, and the intersections between the computational grid and these cones define the boundaries required for grid sectoring. When these cone structures are applied to spherical phased arrays, 3D grid sectoring calculations rapidly compute the pressure fields so that the time required for array design and evaluation is substantially reduced.

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

    NASA Astrophysics Data System (ADS)

    Squire, Jonathan

    2016-10-01

    A novel large-scale dynamo mechanism, the magnetic shear-current effect, is discussed and explored. The effect relies on the interaction of magnetic fluctuations with a mean shear flow, meaning the saturated state of the small-scale dynamo can drive a large-scale dynamo - in some sense the inverse of dynamo quenching. The dynamo is nonhelical, with the mean-field alpha coefficient zero, and is caused by the interaction between an off-diagonal component of the turbulent resistivity and stretching of the large-scale field by shear flow. In this talk, a variety of computational and analytic studies of this mechanism are discussed, which have been carried out both in regimes where magnetic fluctuations arise self-consistently through the small-scale dynamo and at lower Reynolds numbers. In addition, an heuristic description of the effect is presented, which illustrates the fundamental role played by the pressure response of the fluid and helps explain why the magnetic effect is stronger than its kinematic cousin. As well as being interesting for its applications to general high Reynolds number astrophysical turbulence, where strong small-scale magnetic fluctuations are expected to be prevalent, the magnetic shear-current effect is a likely candidate for large-scale dynamo in the unstratified regions of ionized accretion disks. Supported by the Sherman Fairchild Foundation and DOE (DE-AC02-09-CH11466).

  20. Large-field inflation with multiple axions and the weak gravity conjecture

    NASA Astrophysics Data System (ADS)

    Junghans, Daniel

    2016-02-01

    In this note, we discuss the implications of the weak gravity conjecture (WGC) for general models of large-field inflation with a large number of axions N. We first show that, from the bottom-up perspective, such models admit a variety of different regimes for the enhancement of the effective axion decay constant, depending on the amount of alignment and the number of instanton terms that contribute to the scalar potential. This includes regimes of no enhancement, power-law enhancement and exponential enhancement with respect to N. As special cases, we recover the Pythagorean enhancement of N-flation, the N and N 3/2 enhancements derived by Bachlechner, Long and McAllister and the exponential enhancement by Choi, Kim and Yun. We then analyze which top-down constraints are put on such models from the requirement of consistency with quantum gravity. In particular, the WGC appears to imply that the enhancement of the effective axion decay constant must not grow parametrically with N for N ≫ 1. On the other hand, recent works proposed that axions might be able to violate this bound under certain circumstances. Our general expression for the enhancement allows us to translate this possibility into a condition on the number of instantons that couple to the axions. We argue that, at large N , models consistent with quantum gravity must either allow super-Planckian field excursions or have an enormous, possibly even exponentially large, number of dominant instanton terms in the scalar potential.

  1. 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.

  2. Design, testing, and evaluation of an air injection grouting system for geothermal bores. Final report

    SciTech Connect

    1998-04-01

    The objective of this research was to examine the feasibility of an air injection grouting system for geothermal bores. The system that was researched used a pressurized blow tank and a small diameter hose (3/4 or 1 inch) to pneumatically transport dry bentonite granules into a wet bore. Upon contact with the annular fluid in the bore, water or drilling mud, the particles hydrated and formed a grout. A valve on the bottom of the tank allowed the feed rate of particles into the hose to be adjusted. Granular bentonites that were tested ranged in particle size from four to fifty mesh. The pneumatic conveying properties of granular bentonites were studied in dry injection tests. For a fifty-foot length of three quarter inch hose, mass flow rates up to 50 lb/min were found at a tank pressure of 25 psi with air flow rates ranging from 8 to 17 scfm for pressures of 15 to 25 psi. Mass flow rates of over 100 lb/min at a pressure of 25 psi were reached with a one inch hose. Air flow rates ranged 27 to 50 scfm for pressures of 15 to 25 psi for the one inch hose. Testing simulating wet bore conditions were also performed. A method of removing the injection hose at a constant rate was found to produce a uniform, high solids content grout. A relationship between mass flow rate and the percent solids of the resulting grout was discovered in test with drilling mud as an annular fluid. The mass flow rate and percent solids relationship for tests in water was influenced by the type of granular bentonite. Permeability coefficients of air injected grouts were found to be similar to those of slurry bentonite grouts. Tests with a sand and bentonite mixture had flow rates similar to those found for straight granular bentonites, although the number of possible valve settings was reduced. The sand/bentonite mixture produced an acceptable grout in wet injection tests once the reduced yield of the mixture, due to the sand, was taken into account. A field trial conducted with the Solinst

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Development project of high-field facilities at NRIM

    NASA Astrophysics Data System (ADS)

    Inoue, K.; Kiyoshi, T.; Asano, T.; Itoh, K.; Takeuchi, T.; Wada, H.; Maeda, H.

    1990-06-01

    Several high field facilities are now being developed at the National Research Institute for Metals. The systems of a 80 T class long-pulsed magnet and a 20 T class large-bore superconducting magnet are under construction. The primary design of a 40 T class hybrid magnet with relevant facilities has been worked out as a result of the first stage research and development study.

  8. 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

  9. 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).

  10. 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.

  11. 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.

  12. 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.

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

    PubMed

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

    2016-10-13

    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.

  14. 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

  15. The effects of luminance contribution from large fields to chromatic visual evoked potentials.

    PubMed

    Skiba, Rafal M; Duncan, Chad S; Crognale, Michael A

    2014-02-01

    Though useful from a clinical and practical standpoint uniform, large-field chromatic stimuli are likely to contain luminance contributions from retinal inhomogeneities. Such contribution can significantly influence psychophysical thresholds. However, the degree to which small luminance artifacts influence the chromatic VEP has been debated. In particular, claims have been made that band-pass tuning observed in chromatic VEPs result from luminance intrusion. However, there has been no direct evidence presented to support these claims. Recently, large-field isoluminant stimuli have been developed to control for intrusion from retinal inhomogeneities with particular regard to the influence of macular pigment. We report here the application of an improved version of these full-field stimuli to directly test the influence of luminance intrusion on the temporal tuning of the chromatic VEP. Our results show that band-pass tuning persists even when isoluminance is achieved throughout the extent of the stimulus. In addition, small amounts of luminance intrusion affect neither the shape of the temporal tuning function nor the major components of the VEP. These results support the conclusion that the chromatic VEP can depart substantially from threshold psychophysics with regard to temporal tuning and that obtaining a low-pass function is not requisite evidence of selective chromatic activation in the VEP. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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