Science.gov

Sample records for field joint coating

  1. Tar-polyurethane joint coating for the three-layer polyethylene pipeline coating

    SciTech Connect

    Rogers, R.H.

    1996-12-31

    This article describes a new joint coating system implemented by Bechtel for a major international, 48 inch diameter gas pipeline. Despite the long history of use as a pipe and valve coating, the new implementation is the industry`s first significant use of a thermoset hot spray coating applied to field weld areas of pipe, mill coated with a three layer polyethylene system. In the laboratory and in field trials, the coating demonstrated integrity, was applied much quicker than the traditional heat shrink sleeve, and eliminated several application contingencies. Laboratory investigators undertaken in Houston, Texas and Lyon, France were key steps in selecting the 100% solids tar-polyurethane coating. Additionally, the testing assisted in developing the surface preparation technique, and demonstrating the coating`s ability to adhere to the polyethylene coating as well as the steel pipe. Serious localized corrosion, and cathodic protection shielding associated with other joint coatings are less probable with the new joint coating system. Actual field cathodic protection testing indicated very low current consumption for the completed pipeline. The efficient joint coating operation contributed to setting new construction records.

  2. Cryopumping Field Joint Can Testing

    NASA Technical Reports Server (NTRS)

    Johnson, Wesley L.; Fesmire, James E.; Meneghelli, Barry E.

    2011-01-01

    For long installations, vacuum jacketed piping often comes in 40 foot sections that are butt welded together in the field. A short can is then welded over the bare pipe connection to allow for insulation to be protected from the environment. Traditionally, the field joint is insulated with multilayer insulation and a vacuum is pulled on the can to minimize heat leak through the bare section and prevent frost from forming on the pipe section. The vacuum jacketed lines for the Ares I mobile launch platform were to be a combined 2000 feet long, with 60+ pipe sections and field joint cans. Historically, Kennedy Space Center has drilled a hole in the long sections to create a common vacuum with the field joint can to minimize maintenance on the vacuum jacketed piping. However, this effort looked at ways to use a passive system that didn't require a vacuum, but may cryopump to create its own vacuum. Various forms of aerogel, multilayer insulations, and combinations thereof were tested to determine the best method of insulating the field joint while minimizing maintenance and thermal losses.

  3. Development of molded, coated fabric joints: Fabric construction criteria for a spacesuit elbow joint

    NASA Technical Reports Server (NTRS)

    Olson, L. H.

    1981-01-01

    The design and fabrication of a molded, coated fabric elbow joint capable of operating reliably at 8 psi internal pressure for extended periods of flexure is considered. The overall design of the joint includes: (1) selection of heatsettable fiber of sufficient strengths; (2) choosing an optimum fabric construction; (3) a fatigue resistant; flexible coating; and (4) a molding technique. A polyester yarn of type 56 Dacron and a urethane coating system were selected. The relationships between yarn and weave parameters which lead to an optimum fabric construction for the 8 psi elbow joint are defined.

  4. Dissolution behaviour of silicon nitride coatings for joint replacements.

    PubMed

    Pettersson, Maria; Bryant, Michael; Schmidt, Susann; Engqvist, Håkan; Hall, Richard M; Neville, Anne; Persson, Cecilia

    2016-05-01

    In this study, the dissolution rate of SiNx coatings was investigated as a function of coating composition, in comparison to a cobalt chromium molybdenum alloy (CoCrMo) reference. SiNx coatings with N/Si ratios of 0.3, 0.8 and 1.1 were investigated. Electrochemical measurements were complemented with solution (inductively coupled plasma techniques) and surface analysis (vertical scanning interferometry and x-ray photoelectron spectroscopy). The dissolution rate of the SiNx coatings was evaluated to 0.2-1.4nm/day, with a trend of lower dissolution rate with higher N/Si atomic ratio in the coating. The dissolution rates of the coatings were similar to or lower than that of CoCrMo (0.7-1.2nm/day). The highest nitrogen containing coating showed mainly Si-N bonds in the bulk as well as at the surface and in the dissolution area. The lower nitrogen containing coatings showed Si-N and/or Si-Si bonds in the bulk and an increased formation of Si-O bonds at the surface as well as in the dissolution area. The SiNx coatings reduced the metal ion release from the substrate. The possibility to tune the dissolution rate and the ability to prevent release of metal ions encourage further studies on SiNx coatings for joint replacements. PMID:26952452

  5. Iron aluminide alloy coatings and joints, and methods of forming

    DOEpatents

    Wright, Richard N.; Wright, Julie K.; Moore, Glenn A.

    1994-01-01

    A method of joining two bodies together, at least one of the bodies being predominantly composed of metal, the two bodies each having a respective joint surface for joining with the joint surface of the other body, the two bodies having a respective melting point, includes the following steps: a) providing aluminum metal and iron metal on at least one of the joint surfaces of the two bodies; b) after providing the aluminum metal and iron metal on the one joint surface, positioning the joint surfaces of the two bodies in juxtaposition against one another with the aluminum and iron positioned therebetween; c) heating the aluminum and iron on the juxtaposed bodies to a temperature from greater than or equal to 600.degree. C. to less than the melting point of the lower melting point body; d) applying pressure on the juxtaposed surfaces; and e) maintaining the pressure and the temperature for a time period effective to form the aluminum and iron into an iron aluminide alloy joint which bonds the juxtaposed surfaces and correspondingly the two bodies together. The method can also effectively be used to coat a body with an iron aluminide coating.

  6. Iron aluminide alloy coatings and joints, and methods of forming

    DOEpatents

    Wright, R.N.; Wright, J.K.; Moore, G.A.

    1994-09-27

    Disclosed is a method of joining two bodies together, at least one of the bodies being predominantly composed of metal, the two bodies each having a respective joint surface for joining with the joint surface of the other body, the two bodies having a respective melting point, includes the following steps: (a) providing aluminum metal and iron metal on at least one of the joint surfaces of the two bodies; (b) after providing the aluminum metal and iron metal on the one joint surface, positioning the joint surfaces of the two bodies in juxtaposition against one another with the aluminum and iron positioned therebetween; (c) heating the aluminum and iron on the juxtaposed bodies to a temperature from greater than or equal to 600 C to less than the melting point of the lower melting point body; (d) applying pressure on the juxtaposed surfaces; and (e) maintaining the pressure and the temperature for a time period effective to form the aluminum and iron into an iron aluminide alloy joint which bonds the juxtaposed surfaces and correspondingly the two bodies together. The method can also effectively be used to coat a body with an iron aluminide coating.

  7. 21 CFR 888.3565 - Knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Knee joint patellofemorotibial metal/polymer... Devices § 888.3565 Knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis. (a) Identification. A knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis is a...

  8. 21 CFR 888.3565 - Knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Knee joint patellofemorotibial metal/polymer... Devices § 888.3565 Knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis. (a) Identification. A knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis is a...

  9. 21 CFR 888.3565 - Knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Knee joint patellofemorotibial metal/polymer... Devices § 888.3565 Knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis. (a) Identification. A knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis is a...

  10. 21 CFR 888.3565 - Knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint patellofemorotibial metal/polymer... Devices § 888.3565 Knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis. (a) Identification. A knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis is a...

  11. 21 CFR 888.3565 - Knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Knee joint patellofemorotibial metal/polymer... Devices § 888.3565 Knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis. (a) Identification. A knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis is a...

  12. QM-8 field joint protection system, volume 7

    NASA Technical Reports Server (NTRS)

    Hale, Elgie

    1989-01-01

    The pre-launch functioning data of the Field Joint Protection System (JPS) used on QM-8 are presented. Also included is the post fire condition of the JPS components following the test firing of the motor. The JPS components are: field joint heaters; field joint sensors; field joint moisture seal; moisture seal kevlar retaining straps; field joint external extruded cork insulation; vent valve; power cables; and igniter heater.

  13. Conductance Degradation in HTS Coated Conductor Solder Joints

    NASA Astrophysics Data System (ADS)

    Canavan, Edgar R.; Leidecker, Henning; Panashchenko, Lyudmyla

    2015-12-01

    Solder joints between YBCO coated conductors and normal metal traces have been analysed as part of an effort to develop a robust HTS lead assembly for a spaceflight mission. Measurements included critical current and current transfer profiles. X-ray micrographs were used to verify proper solder flow and to determine the extent of voiding. SEM of cross-sections with EDS analysis was crucial in understanding the diffusion of the protective silver layer over the YBCO into the solder for different solder processes. The assembly must be stored for an extended period of time prior to final cool-down and operation. Measurements of the joint resistance over the course of months show a significant increase with time. Understanding the interface condition suggests an explanation for the change.

  14. Architectural design of diamond-like carbon coatings for long-lasting joint replacements.

    PubMed

    Liu, Yujing; Zhao, Xiaoli; Zhang, Lai-Chang; Habibi, Daryoush; Xie, Zonghan

    2013-07-01

    Surface engineering through the application of super-hard, low-friction coatings as a potential approach for increasing the durability of metal-on-metal replacements is attracting significant attention. In this study innovative design strategies are proposed for the development of diamond-like-carbon (DLC) coatings against the damage caused by wear particles on the joint replacements. Finite element modeling is used to analyze stress distributions induced by wear particles of different sizes in the newly-designed coating in comparison to its conventional monolithic counterpart. The critical roles of architectural design in regulating stress concentrations and suppressing crack initiation within the coatings is elucidated. Notably, the introduction of multilayer structure with graded modulus is effective in modifying the stress field and reducing the magnitude and size of stress concentrations in the DLC diamond-like-carbon coatings. The new design is expected to greatly improve the load-carrying ability of surface coatings on prosthetic implants, in addition to the provision of damage tolerance through crack arrest. PMID:23623097

  15. Silicon oxynitride: A field emission suppression coating

    NASA Astrophysics Data System (ADS)

    Theodore, Nimel D.

    We have studied coatings deposited using our inductively-coupled RF plasma ion implantation and desposition system to suppress field emission from large, 3-D electrode structures used in high voltage applications, like those used by Thomas Jefferson National Accelerator Facility in their DC-field photoelectron gun. Currently time and labor-intensive hand-polishing procedures are used to minimize field emission from these structures. Previous work had shown that the field emission from polished stainless steel (27 muA of field-emitted current at 15 MV/m) could be drastically reduced with simultaneous deposition of sputtered silicon dioxide during nitrogen implantation (167 pA of field-emitted current at 30 MV/m). We have determined that this unique implantation and deposition procedure produces high-purity silicon oxynitride films that can suppress field emission from stainless steel regardless of their initial surface polish. However, when this implantation procedure was applied to large, 3-D substrates, arcs occurred, damaging the coating and causing unreliable and unrepeatable field emission suppression. We have developed a novel reactive sputtering procedure to deposit high-purity silicon oxynitride coatings without nitrogen ion implantation. We can control the stoichometry and deposition rate of these coatings by adjusting the nitrogen pressure and incident RF-power. Using profilometry, Auger electron spectroscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, Rutherford backscattering spectrometry, elastic recoil detection analysis, and current-voltage measurements, we have determined that the elemental composition, chemical bonding, density, and electrical properties of the reactively-sputtered silicon oxynitride coatings are similar to those produced by nitrogen implantation during silicon dioxide deposition. Furthermore, high voltage tests determined that both coatings similarly suppress field emission from 6" diameter, polished

  16. Joint of REBa2Cu3O7-δ Coated Conductors Using Metal Organic Deposition

    NASA Astrophysics Data System (ADS)

    Hiramatsu, K.; Teranishi, R.; Yamada, K.; Sato, Y.; Kaneko, K.

    Joint techniques connecting REBa2Cu3O7-δ(REBCO) coated conductors (CCs) are required to fabricate long length CCs and to repair locally damaged one. Two pieces of REBCO CC were attempted to be jointed using a metal organic deposition (MOD) method. The starting solution for YBCO layer was coated on GdBCO layer of CCs and calcined to fabricate precursor films, two of which were stuck together in a face to face manner, and then these films were pressurized and crystallized to joint them. Two CCs were successfully jointed together with c-axis oriented YBCO without pores and reacted phases at the joint interface.

  17. Structural behavior of solid rocket motor field joints

    NASA Technical Reports Server (NTRS)

    Card, Michael F.; Wingate, Robert T.

    1987-01-01

    Structural analysis studies conducted on three concepts for the Space Shuttle Solid Rocket Motor field joints are summarized. Deflections and stresses in the Challenger clevis-tang joint are compared with a proposed capture-tang replacement joint and with an alternate bolted joint design. Results indicate deflections and stresses are subsequently reduced in both the capture-tang and bolted joint concepts. The capture-tang and bolted joint designs are respectively 24 and 70 percent heavier than the baseline clevis-tang joint.

  18. PAINT COATINGS: CONTROLLED FIELD AND CHAMBER EXPERIMENTS

    EPA Science Inventory

    To determine the impact of pollution levels on the weathering rates of coatings, laboratory chamber experiments and controlled field exposures at North Carolina and Ohio sites were conducted in such a manner to separate the contributions due to dry deposition, wet deposition, pre...

  19. Hexavalent Chrome Free Coatings for Electronics Applications: Joint Test Report

    NASA Technical Reports Server (NTRS)

    Rothgeb, Matt; Kessel, Kurt

    2013-01-01

    The overall objective of the Hexavalent Chrome Free Coatings for Electronics Applications project is to evaluate and test pretreatments not containing hexavalent chrome in avionics and electronics housing applications. This objective will be accomplished by testing strong performing coating systems from prior NASA and DoD testing or new coating systems as determined by the stakeholders.

  20. 21 CFR 888.3358 - Hip joint metal/polymer/metal semi-constrained porous-coated uncemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hip joint metal/polymer/metal semi-constrained... Devices § 888.3358 Hip joint metal/polymer/metal semi-constrained porous-coated uncemented prosthesis. (a) Identification. A hip joint metal/polymer/metal semi-constrained porous-coated uncemented prosthesis is a...

  1. 21 CFR 888.3358 - Hip joint metal/polymer/metal semi-constrained porous-coated uncemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Hip joint metal/polymer/metal semi-constrained... Devices § 888.3358 Hip joint metal/polymer/metal semi-constrained porous-coated uncemented prosthesis. (a) Identification. A hip joint metal/polymer/metal semi-constrained porous-coated uncemented prosthesis is a...

  2. Surface pressure field mapping using luminescent coatings

    NASA Technical Reports Server (NTRS)

    Mclachlan, B. G.; Kavandi, J. L.; Callis, J. B.; Gouterman, M.; Green, E.; Khalil, G.; Burns, D.

    1993-01-01

    In recent experiments we demonstrated the feasibility of using the oxygen dependence of luminescent molecules for surface pressure measurement in aerodynamic testing. This technique is based on the observation that for many luminescent molecules the light emitted increases as the oxygen partial pressure, and thus the air pressure, the molecules see decreases. In practice the surface to be observed is coated with an oxygen permeable polymer containing a luminescent molecule and illuminated with ultraviolet radiation. The airflow induced surface pressure field is seen as a luminescence intensity distribution which can be measured using quantitative video techniques. Computer processing converts the video data into a map of the surface pressure field. The experiments consisted of evaluating a trial luminescent coating in measuring the static surface pressure field over a two-dimensional NACA-0012 section model airfoil for Mach numbers ranging from 0.3 and 0.66. Comparison of the luminescent coating derived pressures were made to those obtained from conventional pressure taps. The method along with the experiment and its results will be described.

  3. Fabrication and evaluation of SixNy coatings for total joint replacements.

    PubMed

    Olofsson, J; Pettersson, M; Teuscher, N; Heilmann, A; Larsson, K; Grandfield, K; Persson, C; Jacobson, S; Engqvist, H

    2012-08-01

    Wear particles from the bearing surfaces of joint implants are one of the main limiting factors for total implant longevity. Si(3)N(4) is a potential wear resistant alternative for total joint replacements. In this study, Si(x)N(y)-coatings were deposited on cobalt chromium-discs and Si-wafers by a physical vapour deposition process. The tribological properties, as well as surface appearance, chemical composition, phase composition, structure and hardness of these coatings were analysed. The coatings were found to be amorphous or nanocrystalline, with a hardness and coefficient of friction against Si(3)N(4) similar to that found for bulk Si(3)N(4). The low wear rate of the coatings indicates that they have a potential as bearing surfaces of joint replacements. The adhesion to the substrates remains to be improved. PMID:22689010

  4. Tantalum as a buffer layer in diamond-like carbon coated artificial hip joints.

    PubMed

    Kiuru, Mirjami; Alakoski, Esa; Tiainen, Veli-Matti; Lappalainen, Reijo; Anttila, Asko

    2003-07-15

    The acid resistance of tantalum coated and uncoated human hip joint prostheses was studied with commercial CrCoMo acetabular cups. The samples were exposed to 10% HCl solution and the quantities of dissolved Cr, Co, and Mo were measured with proton-induced X-ray emission (PIXE). The absolute quantities were obtained with the use of Cr and Se solution standards. Tantalum coatings (thicknesses 4-6 microm) were prepared in vacuum with magnetron sputtering. Tantalum coating decreased the corrosion rate by a factor of 10(6). As a spinoff from recent wear tests on artificial hip joints it was shown that tantalum has excellent mechanical properties as an intermediate layer of diamond-like carbon (DLC) coatings. When tantalum was tested together with DLC on three metal-on-metal hip joint pairs in a hip simulator, no observable defects occurred during 15 million walking cycles with a periodic 50-300-kg load (Paul curve). PMID:12808604

  5. Diamond coated silicon field emitter array

    SciTech Connect

    S. Albin; W. Fu; A. Varghese; A. C. Lavarias; G. R. Myneni

    1999-07-01

    Diamond coated silicon tip arrays, with and without a self-aligned gate, were fabricated, and current-voltage characteristics of 400 tips were measured. Diamond films were grown uniformly on Si tips using microwave plasma after nucleation with 10 nm diamond suspension and substrate bias. An emission current of 57 ?A was obtained at 5 V from the ungated array tips separated from an anode at 2 ?m. In the case of the gated arrays with 1.5 ?m aperture, an emission current of 3.4 ?A was measured at a gate voltage of 80 V for an anode separation of 200 ?m. The turn-on voltages for these two types of devices were 0.2 and 40 V, respectively. Diamond coated Si tip arrays have potential applications in field emission based low voltage vacuum electronic devices and microsensors.

  6. Solid rocket motor aft field joint flow field analysis

    NASA Technical Reports Server (NTRS)

    Sabnis, Jayant S.; Gibeling, Edward J.; Mcdonald, Henry

    1987-01-01

    An efficient Navier-Stokes analysis was successfully applied to simulate the complex flow field in the vicinity of a slot in a solid rocket motor with segment joints. The capability of the computer code to resolve the flow near solid surfaces without using a wall function assumption was demonstrated. In view of the complex nature of the flow field in the vicinity of the slot, this approach is considered essential. The results obtained from these calculations provide valuable design information, which would otherwise be extremely difficult to obtain. The results of the axisymmetric calculations indicate the presence of a region of reversed axial flow at the aft-edge of the slot and show the over-pressure in the slot to be only about 10 psi. The results of the asymmetric calculations indicate that a pressure asymmetry more than two diameters downstream of the slot has no noticeable effect on the flow field in the slot. They also indicate that the circumferential pressure differential caused in the slot due to failure of a 15 deg section of the castable inhibitor will be approximately 1 psi.

  7. Portable power tool machines weld joints in field

    NASA Technical Reports Server (NTRS)

    Spier, R. A.

    1966-01-01

    Portable routing machine for cutting precise weld joints required by nonstandard pipe sections used in the field for transfer of cryogenic fluids. This tool is adaptable for various sizes of pipes and has a selection of router bits for different joint configurations.

  8. Protective coatings for columbium applied in the field.

    NASA Technical Reports Server (NTRS)

    Carter, J.; Culp, J.

    1971-01-01

    The various aspects of field repair of columbium alloy panels with protective coatings designed as part of the Space Shuttle thermal protection system are examined. The field repair of the coatings is accomplished by employing ceramic cement repairs, and reapplying the fused slurry silicide coating. Techniques are described which improve the practicality of these repairs by employing torch heating. The repair coating quality is demonstrated by testing which simulates flight temperature, pressure, stress and acoustic vibration conditions as a function of time. Conclusions on the present status of field repair coatings are presented and recommendations are given for appropriate future activities relative to the use on an operational Space Shuttle system.

  9. 21 CFR 888.3535 - Knee joint femorotibial (uni-compartmental) metal/polymer porous-coated uncemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    .../polymer porous-coated uncemented prosthesis. 888.3535 Section 888.3535 Food and Drugs FOOD AND DRUG... Devices § 888.3535 Knee joint femorotibial (uni-compartmental) metal/polymer porous-coated uncemented prosthesis. (a) Identification. A knee joint femorotibial (uni-compartmental) metal/polymer...

  10. 21 CFR 888.3535 - Knee joint femorotibial (uni-compartmental) metal/polymer porous-coated uncemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    .../polymer porous-coated uncemented prosthesis. 888.3535 Section 888.3535 Food and Drugs FOOD AND DRUG... Devices § 888.3535 Knee joint femorotibial (uni-compartmental) metal/polymer porous-coated uncemented prosthesis. (a) Identification. A knee joint femorotibial (uni-compartmental) metal/polymer...

  11. Hexavalent Chrome Free Coatings for Electronics Applications: Joint Test Report

    NASA Technical Reports Server (NTRS)

    Kessel, Kurt

    2012-01-01

    Regardless of the corrosivity of the environment, all metals require periodic maintenance activity to guard against the insidious effects of corrosion and thus ensure that alloys meet or exceed design or performance life. The standard practice for protecting metallic substrates is the application of a coating system. Applied coating systems work via a variety of methods (barrier, galvanic, and/or inhibitor) and adhere to the substrate through a combination of chemical and physical bonds. For years hexavalent chromium has been a widely used element within applied coating systems because of its self healing and corrosion resistant properties. Occupational Safety and Health Administration (OSHA) studies have concluded that hexavalent chromium (hex chrome) is carcinogenic and poses significant risk to human health. On May 5, 2011 amendments to the Defense Federal Acquisition Regulation Supplement (DFARS) were issued in the Federal Register. Subpart 223.73 prohibits contracts from requiring hexavalent chromium in deliverables unless certain exceptions apply. These exceptions include authorization from a general or flag officer and members of the Senior Executive Service from a Program Executive Office, and unmodified legacy systems. Otherwise, Subpart 252.223-7008 provides the contract clause prohibiting contractors from using or delivering hexavalent chromium in a concentration greater than 0.1 percent by weight for all new contracts and to be included down to subcontractors for supplies, maintenance and repair services, and construction materials. National Aeronautics and Space Administration (NASA), Department of Defense (DoD), and industry stakeholders continue to search for alternatives to hex chrome in coatings applications that meet their performance requirements in corrosion protection, cost, operability, and health and safety, while typically specifying that performance must be equal to or greater than existing systems.

  12. VOLTAGE DISTRIBUTION AND MECHANICAL STRENGTH IN SPLICE JOINTS MADE FROM AS-MANUFACTURED YBCO COATED CONDUCTORS

    SciTech Connect

    Duckworth, Robert C; Zhang, Yifei; Gouge, Michael J; Rey, Christopher M; Van der Laan, Danko; Clickner, Cam

    2010-01-01

    With recommendations from wire manufacturers as a starting point, a series of solder joints were fabricated and characterized to determine the best method to produce repeatable, low-resistance and high-mechanical-strength splices in as-manufactured, stabilized YBCO coated conductors. From the 2.54 cm long splice joints that were fabricated, parameters such as solder material, stabilization material, fabrication method, and conductor geometry were varied to determine the impact of each on splice joint properties. Results indicate that the lowest resistance splice joints were influenced primarily by the tape orientation in the joint and the stabilization material. The lowest resistances were between 2 10-8 and 1.0 10-7 in 4-mm wide tapes and were obtained from pure copper stabilized tapes oriented with the YBCO layers in closest proximity. The voltage drop along the splice length indicated that only a fraction of the splice length contributes to the splice joint resistance. Mechanical characterization of splice joints showed that the joint resistance remained unchanged under axial stress up to a stress level at which the critical current of the tapes forming the joint degrades irreversibly.

  13. 21 CFR 888.3535 - Knee joint femorotibial (uni-compartmental) metal/polymer porous-coated uncemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Knee joint femorotibial (uni-compartmental) metal... Devices § 888.3535 Knee joint femorotibial (uni-compartmental) metal/polymer porous-coated uncemented prosthesis. (a) Identification. A knee joint femorotibial (uni-compartmental) metal/polymer...

  14. 21 CFR 888.3535 - Knee joint femorotibial (uni-compartmental) metal/polymer porous-coated uncemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Knee joint femorotibial (uni-compartmental) metal... Devices § 888.3535 Knee joint femorotibial (uni-compartmental) metal/polymer porous-coated uncemented prosthesis. (a) Identification. A knee joint femorotibial (uni-compartmental) metal/polymer...

  15. 21 CFR 888.3535 - Knee joint femorotibial (uni-compartmental) metal/polymer porous-coated uncemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Knee joint femorotibial (uni-compartmental) metal... Devices § 888.3535 Knee joint femorotibial (uni-compartmental) metal/polymer porous-coated uncemented prosthesis. (a) Identification. A knee joint femorotibial (uni-compartmental) metal/polymer...

  16. 21 CFR 888.3670 - Shoulder joint metal/polymer/metal nonconstrained or semi-constrained porous-coated uncemented...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Shoulder joint metal/polymer/metal nonconstrained... ORTHOPEDIC DEVICES Prosthetic Devices § 888.3670 Shoulder joint metal/polymer/metal nonconstrained or semi-constrained porous-coated uncemented prosthesis. (a) Identification. A shoulder joint...

  17. 21 CFR 888.3670 - Shoulder joint metal/polymer/metal nonconstrained or semi-constrained porous-coated uncemented...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Shoulder joint metal/polymer/metal nonconstrained... ORTHOPEDIC DEVICES Prosthetic Devices § 888.3670 Shoulder joint metal/polymer/metal nonconstrained or semi-constrained porous-coated uncemented prosthesis. (a) Identification. A shoulder joint...

  18. A robotic apparatus that dictates torque fields around joints without affecting inherent joint dynamics.

    PubMed

    Oytam, Yalchin; Lloyd, David; Reid, Campbell S; de Rugy, Aymar; Carson, Richard G

    2010-10-01

    This manuscript describes how motor behaviour researchers who are not at the same time expert roboticists may implement an experimental apparatus, which has the ability to dictate torque fields around a single joint on one limb or single joints on multiple limbs without otherwise interfering with the inherent dynamics of those joints. Such an apparatus expands the exploratory potential of the researcher wherever experimental distinction of factors may necessitate independent control of torque fields around multiple limbs, or the shaping of torque fields of a given joint independently of its plane of motion, or its directional phase within that plane. The apparatus utilizes torque motors. The challenge with torque motors is that they impose added inertia on limbs and thus attenuate joint dynamics. We eliminated this attenuation by establishing an accurate mathematical model of the robotic device using the Box-Jenkins method, and cancelling out its dynamics by employing the inverse of the model as a compensating controller. A direct measure of the remnant inertial torque as experienced by the hand during a 50 s period of wrist oscillations that increased gradually in frequency from 1.0 to 3.8 Hz confirmed that the removal of the inertial effect of the motor was effectively complete. PMID:20728232

  19. Retrospective lifetime estimation of failed and explanted diamond-like carbon coated hip joint balls.

    PubMed

    Hauert, R; Falub, C V; Thorwarth, G; Thorwarth, K; Affolter, Ch; Stiefel, M; Podleska, L E; Taeger, G

    2012-08-01

    Diamond-like carbon (DLC) coatings are known to have extremely low wear in many technical applications. The application of DLC as a coating has aimed at lowering wear and to preventing wear particle-induced osteolysis in artificial hip joints. In a medical study femoral heads coated with diamond-like amorphous carbon, a subgroup of DLC, articulating against polyethylene cups were implanted between 1993 and 1995. Within 8.5 years about half of the hip joints had to be revised due to aseptic loosening. The explanted femoral heads showed many spots of local coating delamination. Several of these explanted coated TiAlV femoral heads have been analyzed to investigate the reason for this failure. Raman analysis and X-ray photoelectron spectroscopy (XPS) depth profiling showed that the coating consists of diamond-like amorphous carbon, several Si-doped layers and an adhesion-promoting Si interlayer. Focused ion beam (FIB) transverse cuts revealed that the delamination of the coatings is caused by in vivo corrosion of the Si interlayer. Using a delamination test set-up dissolution of the silicon adhesion-promoting interlayer at a speed of more than 100 μm year(-1) was measured in vitro in solutions containing proteins. Although proteins are not directly involved in the corrosion reactions, they can block existing small cracks and crevices under the coating, hindering the exchange of liquid. This results in a build-up of crevice corrosion conditions in the crack, causing a slow dissolution of the Si interlayer. PMID:22521966

  20. Flight Set 360L002 (STS-27) field joint protection system, volume 7

    NASA Technical Reports Server (NTRS)

    Hale, Elgie

    1989-01-01

    This report contains the pre-launch functioning data of the Field Joint Protection System (JPS) used on STS-27. Also included is the post flight condition of the JPS components following the launch and recovery of the two redesigned solid rocket motors (RSRM) boosters. The JPS components are: (1) field joint heaters; (2) field joint sensors; (3) field joint moisture seal; (4) moisture seal Kevlar retaining straps; (5) field joint external insulation; (6) vent valve; (7) power cables; and (8) igniter heater.

  1. Jointing of Coated Conductors by Using Nano-particle Metal Pastes

    NASA Astrophysics Data System (ADS)

    Nakanishi, Tsuyoshi; Machi, Takato; Izumi, Teruo; Teranishi, Ryo; Kato, Tomohiro; Kato, Takeharu; Hirayama, Tsukasa

    Development of a jointing technique of coated conductors is important for all applications, such as superconducting magnets, cables, etc. Low resistance jointing techniques by means of silver diffusion [1] and for superconducting joints[2] have been reported so far. Since these processes were carried out at higher temperatures than the O2 annealing temperature for appropriate carrier doping to the REBa2Cu3O7-d (REBCO) crystals and resulted in oxygen deficiency in the REBCO crystals, long time O2 annealing was required for compensation of this oxygen deficiency. Because the long time and high temperature post annealing is an inappropriate process as on-site technology, solder jointing technology has been widely accepted, in general, for practical applications. However, the resistance of the solder joint is 50 - 100 nΩ, and then the Joule heat generation in the joint region is a serious problem and must be solved. Consequently, we have studied a new jointing technique by using the pastes containing of silver or gold nano-particles. Because the Ic value of GdBCO was deteriorated with higher temperature heat treatment, we have tried to develop a jointing technology with the low temperature (below 200°C). We used the nano-particle metal pastes (∼5 nm) which contained dispersants around the chemically active surface of nano-particles and dissociates at low temperatures and achieved the low resistance joint (∼ 3nΩ, 10 x 160 mm2, 77 K) as well as no Ic degradation without O2 post annealing.

  2. Mechanical and tribological behavior of silicon nitride and silicon carbon nitride coatings for total joint replacements.

    PubMed

    Pettersson, M; Tkachenko, S; Schmidt, S; Berlind, T; Jacobson, S; Hultman, L; Engqvist, H; Persson, C

    2013-09-01

    Total joint replacements currently have relatively high success rates at 10-15 years; however, increasing ageing and an active population places higher demands on the longevity of the implants. A wear resistant configuration with wear particles that resorb in vivo can potentially increase the lifetime of an implant. In this study, silicon nitride (SixNy) and silicon carbon nitride (SixCyNz) coatings were produced for this purpose using reactive high power impulse magnetron sputtering (HiPIMS). The coatings are intended for hard bearing surfaces on implants. Hardness and elastic modulus of the coatings were evaluated by nanoindentation, cohesive, and adhesive properties were assessed by micro-scratching and the tribological performance was investigated in a ball-on-disc setup run in a serum solution. The majority of the SixNy coatings showed a hardness close to that of sintered silicon nitride (~18 GPa), and an elastic modulus close to that of cobalt chromium (~200 GPa). Furthermore, all except one of the SixNy coatings offered a wear resistance similar to that of bulk silicon nitride and significantly higher than that of cobalt chromium. In contrast, the SixCyNz coatings did not show as high level of wear resistance. PMID:23726925

  3. Improved Photoresist Coating for Making CNT Field Emitters

    NASA Technical Reports Server (NTRS)

    Toda, Risaku; Manohara, Harish

    2009-01-01

    An improved photoresist-coating technique has been developed for use in the fabrication of carbon-nanotube- (CNT) based field emitters is described. The improved photoresist coating technique overcomes what, heretofore, has been a major difficulty in the fabrication process.

  4. Field joint environmental protection system vibration/pressurization qualification

    NASA Technical Reports Server (NTRS)

    Cook, M.

    1989-01-01

    The procedures used and results obtained from vibration testing the redesigned solid rocket motor (RSRM) field joint environmental protection system (FJEPS), hereafter referred to as the joint protection system (JPS) are documented. The major purposes were to certify that the flight-designed JPS will withstand the dynamic environmental conditions of the redesigned solid rocket booster, and to certify that the cartridge check valve (vent valve) will relieve pressure build-up under the JPS during the initial 120 sec of flight. Also, an evaluation of the extruded cork insulation bonding was performed after the vibration testing.

  5. Field repair of coated columbium Thermal Protection System (TPS)

    NASA Technical Reports Server (NTRS)

    Culp, J. D.

    1972-01-01

    The requirements for field repair of coated columbian panels were studied, and the probable cause of damage were identified. The following types of repair methods were developed, and are ready for use on an operational system: replacement of fused slurrey silicide coating by a short processing cycle using a focused radiant spot heater; repair of the coating by a glassy matrix ceramic composition which is painted or sprayed over the defective area; and repair of the protective coating by plasma spraying molybdenum disilicide over the damaged area employing portable equipment.

  6. Development of a superconducting joint between a GdBa2Cu3O7-δ-coated conductor and YBa2Cu3O7-δ bulk: towards a superconducting joint between RE (Rare Earth) Ba2Cu3O7-δ-coated conductors

    NASA Astrophysics Data System (ADS)

    Jin, Xinzhe; Yanagisawa, Yoshinori; Maeda, Hideaki; Takano, Yoshiki

    2015-07-01

    We have started to develop a superconducting bridge joint between two GdBa2Cu3O7-δ (Gd123)-coated conductors, where both conductors are placed in an end-to-end arrangement on the surface of a melt-textured YBCO (including Y2BaCuO5 and YBa2Cu3O7-δ) bulk, which acts as a superconducting medium between the coated conductors. As a first step in the development, one half of the bridge joint assembly was modeled and investigated. Experimental results achieved are as follows: (a) the higher-melting-temperature textured Gd123-coated conductor acts as a seed for the melt texture of the YBa2Cu3O7-δ (Y123) bulk, and (b) the superconducting phase continues across the Y123/Gd123 boundary. The critical current of the joint model is 10 A, which is about 10% of the original Gd123-coated conductor, at 77 K in a self-magnetic field. These results are considered to be extensible to the superconducting bridge joint between the Gd123-coated conductors.

  7. NATO TG-25 joint field experiment in distributed sensor networks

    NASA Astrophysics Data System (ADS)

    Mays, Brian; Vu, Hao; Srour, Nino

    2003-09-01

    NATO's Task Group (TG-25) on acoustic and seismic sensing is responsible for assessing the potential technologies that can be cooperatively developed and shared within NATO's countries to provide effective, robust and low-cost battlefield sensor systems. The primary applications will be detection and/or classification of ground troops, ground vehicles, airborne vehicles, artillery and sniper. TG-25 has 3 main objectives: (1) to establish acoustic and seismic standards and data exchange procedures, (2) to compare, analyze, exchange, and develop analytical techniques, computational models and signal processing algorithms, and (3) to plan and conduct joint field experiments. In this paper, we discuss participation in the joint NATO field experiment conducted in France in October 2002. The experiment's goal is to demonstrate interoperability of unattended ground sensors from various participating nations. Results of the experiments will be briefed and discussed. Keywords: TG-25, unattended ground sensor, vehicle tracking

  8. NATO SET-093 joint field experiment at Bourges, France

    NASA Astrophysics Data System (ADS)

    Marty, C.; Bruel, F.; Prieur, D.; Naz, P.; Miller, L. S.

    2009-05-01

    This paper describes the NATO Task Group SET-093/RTG53/MSE (referred to as TG-53 in this report) Acoustic Detection of Weapons Firing Joint Field Experiment II conducted at the Etablissement Technique de Bourges (ETBS), Bourges, France, during 16 to 27 June 2008. This field experiment is a follow-on to the NATO TG-53 Acoustic Detection of Weapons Firing Joint Field Experiment I conducted at the Yuma Proving Grounds (YPG), Yuma, Arizona, USA, during 31 October to 4 November 2005 [1]. The objectives of the joint experiment were: (i) to collect acoustic signatures of direct and indirect firings from weapons' such as small arms, mortars, artillery, rockets, and C4 explosives, (ii) to analyze the propagation effects of grassy, wooded, and urban terrains, (iii) to share signatures collected from a variety of acoustic sensors, on the ground and in the air, distributed over a wide area, and (iv) to demonstrate the interoperability of disparate sensors developed by the various nations involved. The participating NATO countries , including France, the Netherlands, the United Kingdom, Canada, and the United States of America, and Israel as well as part of the Mediterranean dialogue countries, deployed nearly 90 sensors and sensor systems over the test range area.

  9. The High performance of nanocrystalline CVD diamond coated hip joints in wear simulator test.

    PubMed

    Maru, M M; Amaral, M; Rodrigues, S P; Santos, R; Gouvea, C P; Archanjo, B S; Trommer, R M; Oliveira, F J; Silva, R F; Achete, C A

    2015-09-01

    The superior biotribological performance of nanocrystalline diamond (NCD) coatings grown by a chemical vapor deposition (CVD) method was already shown to demonstrate high wear resistance in ball on plate experiments under physiological liquid lubrication. However, tests with a close-to-real approach were missing and this constitutes the aim of the present work. Hip joint wear simulator tests were performed with cups and heads made of silicon nitride coated with NCD of ~10 μm in thickness. Five million testing cycles (Mc) were run, which represent nearly five years of hip joint implant activity in a patient. For the wear analysis, gravimetry, profilometry, scanning electron microscopy and Raman spectroscopy techniques were used. After 0.5 Mc of wear test, truncation of the protruded regions of the NCD film happened as a result of a fine-scale abrasive wear mechanism, evolving to extensive plateau regions and highly polished surface condition (Ra<10nm). Such surface modification took place without any catastrophic features as cracking, grain pullouts or delamination of the coatings. A steady state volumetric wear rate of 0.02 mm(3)/Mc, equivalent to a linear wear of 0.27 μm/Mc favorably compares with the best performance reported in the literature for the fourth generation alumina ceramic (0.05 mm(3)/Mc). Also, squeaking, quite common phenomenon in hard-on-hard systems, was absent in the present all-NCD system. PMID:26024650

  10. An analysis of the flow field in the region of the ASRM field joints

    NASA Astrophysics Data System (ADS)

    Dill, Richard A.; Whitesides, Harold R.

    1992-07-01

    The flow field in the region of a solid rocket motor field joint is very important since fluid dynamic and mechanical propellant stresses can couple to cause a motor failure at a joint. Presented here is an examination of the flow field in the region of the Advanced Solid Rocket Motor (ASRM) field joints. The analyses were performed as a first step in assessing the design of the ASRM forward and aft field joints in order to assure the proper operation of the motor prior to further development of test firing. The analyses presented here were performed by employing a two-dimensional axisymmetric assumption. Fluent/BFC, a three dimensional full Navier-Stokes flow field code, was used to make the numerical calculations. This code utilizes a staggered grid formulation along with the SIMPLER numerical algorithm. Wall functions are used to determine the character of the laminar sublayer, and a standard kappa-epsilon turbulence model is used to close the fluid dynamic equations. The analyses performed to this date verify that the ASRM field joint design operates properly. The fluid dynamic stresses at the field joints are small due to the inherent design of the field joints. A problem observed in some other solid rocket motors is that large fluid dynamic stresses are generated at the motor joint on the downstream propellant grain due to forward facing step geometries. The design of the ASRM field joints are such that this is not a problem as shown by the analyses. Also, the analyses of the inhibitor stub left protruding into the port flow from normal propellant burn back show that more information is necessary to complete these analyses. These analyses were performed as parametric analyses in relation to the height of the inhibitor stub left protruding into the motor port. A better estimate of the amount of the inhibitor stub remaining at later burn times must be determined since the height which the inhibitor stub protrudes into the port flow drastically affects the fluid

  11. An analysis of the flow field in the region of the ASRM field joints

    NASA Technical Reports Server (NTRS)

    Dill, Richard A.; Whitesides, Harold R.

    1992-01-01

    The flow field in the region of a solid rocket motor field joint is very important since fluid dynamic and mechanical propellant stresses can couple to cause a motor failure at a joint. Presented here is an examination of the flow field in the region of the Advanced Solid Rocket Motor (ASRM) field joints. The analyses were performed as a first step in assessing the design of the ASRM forward and aft field joints in order to assure the proper operation of the motor prior to further development of test firing. The analyses presented here were performed by employing a two-dimensional axisymmetric assumption. Fluent/BFC, a three dimensional full Navier-Stokes flow field code, was used to make the numerical calculations. This code utilizes a staggered grid formulation along with the SIMPLER numerical algorithm. Wall functions are used to determine the character of the laminar sublayer, and a standard kappa-epsilon turbulence model is used to close the fluid dynamic equations. The analyses performed to this date verify that the ASRM field joint design operates properly. The fluid dynamic stresses at the field joints are small due to the inherent design of the field joints. A problem observed in some other solid rocket motors is that large fluid dynamic stresses are generated at the motor joint on the downstream propellant grain due to forward facing step geometries. The design of the ASRM field joints are such that this is not a problem as shown by the analyses. Also, the analyses of the inhibitor stub left protruding into the port flow from normal propellant burn back show that more information is necessary to complete these analyses. These analyses were performed as parametric analyses in relation to the height of the inhibitor stub left protruding into the motor port. A better estimate of the amount of the inhibitor stub remaining at later burn times must be determined since the height which the inhibitor stub protrudes into the port flow drastically affects the fluid

  12. Nondestructive Evaluation of Friction Stir-Welded Aluminum Alloy to Coated Steel Sheet Lap Joint

    NASA Astrophysics Data System (ADS)

    Das, H.; Kumar, A.; Rajkumar, K. V.; Saravanan, T.; Jayakumar, T.; Pal, Tapan Kumar

    2015-11-01

    Dissimilar lap joints of aluminum sheet (AA 6061) of 2 mm thickness and zinc-coated steel sheet of 1 mm thickness were produced by friction stir welding with different combinations of rotational speed and travel speed. Ultrasonic C- and B-scanning, and radiography have been used in a complementary manner for detection of volumetric (cavity and flash) and planar (de bond) defects as the defects are in micron level. Advanced ultrasonic C-scanning did not provide any idea about the defects, whereas B-scanning cross-sectional image showed an exclusive overview of the micron-level defects. A digital x-ray radiography methodology is proposed for quality assessment of the dissimilar welds which provide three-fold increase in signal-to-noise ratio with improved defect detection sensitivity. The present study clearly shows that the weld tool rotational speed and travel speed have a decisive role on the quality of the joints obtained by the friction stir welding process. The suitability of the proposed NDE techniques to evaluate the joint integrity of dissimilar FSW joints is thus established.

  13. Pursuing low joint resistivity in Cu-stabilized REBa2Cu3O δ coated conductor tapes by the ultrasonic weld-solder hybrid method

    NASA Astrophysics Data System (ADS)

    Shin, Hyung-Seop; Kim, Jong-min; Dedicatoria, Marlon J.

    2016-01-01

    Development of a coated conductor tape joint with good quality and low joint resistivity, R sj, in terms of transport and mechanical properties, was attempted by direct bonding at the interface of the Cu-Cu stabilizers in overlapped GdBCO CC tapes. In this study, we attempted to achieve a low R sj by introducing hybrid joining, soldering and ultrasonic welding (UW), and its mechanism was analyzed theoretically. Coated conductor tapes were experimentally joined using various methods of soldering, UW, and combinations of the two. As a result, a much lower R sj of about 57 nΩ · cm2 was obtained for RCE-DR-processed GdBCO CC tape joints using the hybrid joining method. The mechanical properties of the jointed CC tapes were also evaluated at room temperature and 77 K under self-field. Load-displacement curves of joined CC tapes followed the curve of the single CC tape. Critical current and joint resistance, R j, of hybrid-joined CC tape were retained after double bending at room temperature up to 20 mm bending diameter.

  14. Joint analysis of spikes and local field potentials using copula.

    PubMed

    Hu, Meng; Li, Mingyao; Li, Wu; Liang, Hualou

    2016-06-01

    Recent technological advances, which allow for simultaneous recording of spikes and local field potentials (LFPs) at multiple sites in a given cortical area or across different areas, have greatly increased our understanding of signal processing in brain circuits. Joint analysis of simultaneously collected spike and LFP signals is an important step to explicate how the brain orchestrates information processing. In this contribution, we present a novel statistical framework based on Gaussian copula to jointly model spikes and LFP. In our approach, we use copula to link separate, marginal regression models to construct a joint regression model, in which the binary-valued spike train data are modeled using generalized linear model (GLM) and the continuous-valued LFP data are modeled using linear regression. Model parameters can be efficiently estimated via maximum-likelihood. In particular, we show that our model offers a means to statistically detect directional influence between spikes and LFP, akin to Granger causality measure, and that we are able to assess its statistical significance by conducting a Wald test. Through extensive simulations, we also show that our method is able to reliably recover the true model used to generate the data. To demonstrate the effectiveness of our approach in real setting, we further apply the method to a mixed neural dataset, consisting of spikes and LFP simultaneously recorded from the visual cortex of a monkey performing a contour detection task. PMID:27012500

  15. Diamond-Coated Carbon Nanotubes for Efficient Field Emission

    NASA Technical Reports Server (NTRS)

    Dimitrijevic, Stevan; Withers, James C.

    2005-01-01

    Field-emission cathodes containing arrays of carbon nanotubes coated with diamond or diamondlike carbon (DLC) are undergoing development. Multiwalled carbon nanotubes have been shown to perform well as electron field emitters. The idea underlying the present development is that by coating carbon nanotubes with wideband- gap materials like diamond or DLC, one could reduce effective work functions, thereby reducing threshold electric-field levels for field emission of electrons and, hence, improving cathode performance. To demonstrate feasibility, experimental cathodes were fabricated by (1) covering metal bases with carbon nanotubes bound to the bases by an electrically conductive binder and (2) coating the nanotubes, variously, with diamond or DLC by plasma-assisted chemical vapor deposition. In tests, the threshold electric-field levels for emission of electrons were reduced by as much as 40 percent, relative to those of uncoated- nanotube cathodes. Coating with diamond or DLC could also make field emission-cathodes operate more stably by helping to prevent evaporation of carbon from nanotubes in the event of overheating of the cathodes. Cathodes of this type are expected to be useful principally as electron sources for cathode-ray tubes and flat-panel displays.

  16. EMAA thermoplastic powder coatings: Shop and field application of powder coatings for aggressive environments

    SciTech Connect

    Loustaunau, P.J.; Horton, D.

    1994-12-31

    This paper deals with how Ethylene Methacrylic Acid thermoplastic powder coatings are allowing asset owners to meet tightening environmental regulations while solving some of their most difficult coating problems. It discusses the versatility of traditional shop application methods and field application/repair methods in the rail and water/waste water treatment areas. EMAA coatings typically perform well in aggressive environments due to their high flexibility and impact resistance. The material`s inherent toughness also provides for excellent abrasion resistance. EMAA demonstrates excellent resistance to chemical attack and is highly resistant to permeation by liquids. Because some aromatic, cyclic and higher aliphatic hydrocarbon solvents may cause swelling and permeate through the coating, caution should be used in immersion applications with this group of solutions.

  17. Study on the anti-wear performance of Ni-base composite coating sucker joint that contains nano-diamond and nano-polytetrafluoroethylene.

    PubMed

    Wang, Wei-Zhang; Yan, Xiang-Zhen; Wang, Hai-Wen; Wang, Ming-Bo

    2009-02-01

    With the development of oilfields, the problem of eccentric wear between casing and sucker rod in rod-pumped wells operation is more and more severe. Investigations on the eccentric wear show that the abrasion of sucker rod joint is more serious than the sucker rod itself. A new method of producing the Ni-base composite coating that contains nano-diamond and nano-polytetrafluoroethylene (PTFE) on sucker joint obtained by electrodeposition is presented in this paper. The test results show that the anti-wear performance and hardness of the sucker rod improve significantly with the increase of nano-diamond. The addition of nano-PTFE particle is useful in reducing the friction factor. Field tests demonstrate that the life of the sucker rod joint is increased and the maintenance cycle of the rod-pumped well is prolonged. PMID:19441509

  18. Strength testing of Ti-vapor-coated silicon nitride braze joints

    SciTech Connect

    Santella, M.L.

    1994-09-01

    Sintered silicon nitride was vacuum brazed to itself at 1130{degree}C with a Au-25Ni-25Pd wt % filler metal. Wetting was obtained by coating the Si{sub 3}N{sub 4} surfaces with titanium prior to brazing by electron beam evaporation. The brazed joints were virtually free of porosity. Metallographic analysis showed that Ti reacted with the Si{sub 3}N{sub 4}, to form a TiN reaction layer during brazing. Small amounts of Si and Ti dissolved in the filler metal layers but they did not appear to influence the mechanical properties of the braze layer. Flexure bars were made from the brazed coupons and tested at room temperature, 600C, 700C, and 800C in air. At 700C and below, fracture of the test bars occurred in the Si{sub 3}N{sub 4}, either near the brazed surfaces or at some distance into the monolithic material. The measured strength of joint specimens decreased slightly with increasing test temperature, and generally exceeded the intrinsic braze filler metal strength in this temperature range. It was also found that lapping the Si{sub 3}N{sub 4}, prior to Ti coating reduced the number of near-surface flaws and produced joints with higher average strength and lower scatter than those left in a ground condition. Specimens tested at 800C had very low strengths, and this behavior was related to the microstructure at the brazed Si{sub 3}N{sub 4} surfaces.

  19. NDE of Space Shuttle Solid Rocket Motor field joint

    NASA Astrophysics Data System (ADS)

    Johnston, Patrick H.

    One of the most critical areas for inspection in the Space Shuttle Solid Rocket Motors is the bond between the steel case and rubber insulation in the region of the field joints. The tang-and-clevis geometry of the field joints is sufficiently complex to prohibit the use of resonance-based techniques. One approach we are investigating is to interrogate the steel-insulation bondline in the tang and clevis regions using surface-travelling waves. A low-frequency contact surface wave transmitting array transducer is under development at our laboratory for this purpose. The array is placed in acoustic contact with the steel and surface waves are launched on the inside surface or the clevis leg which propagate along the steel-insulation interface. As these surface waves propagate along the bonded surface, the magnitude of the ultrasonic energy leaking into the steel is monitored on the outer surface of the case. Our working hypothesis is that the magnitude of energy received at the outer surface of the case is dependent upon the integrity of the case-insulation bond, with less attenuation for propagation along a disbond due to imperfect acoustic coupling between the steel and rubber. Measurements on test specimens indicate a linear relationship between received signal amplitude and the length of good bend between the transmitter and receiver, suggesting the validity of this working hypothesis.

  20. Field joint protection system rain qualification test report

    NASA Technical Reports Server (NTRS)

    Cook, M.

    1989-01-01

    This report documents the procedures, performance, and results obtained from the Field Joint Protection System (FJPS) rain test. This test was performed to validate that the flight configuration FJPS prevents the accumulation of moisture in the redesigned solid rocket motor (RSRM) field joints when subjected to simulated prelaunch natural rain environments. The FJPS test article was exposed to rain simulation for approximately 50 minutes. During the test, water entered through the open upper end of the systems tunnel and was funneled down between the tunnel and case. A sealant void at the moisture seal butt splice allowed this water to flow underneath the FJPS. The most likely cause of voids was improper bondline preparation, particularly on the moisture seal surface. In total, water penetrated underneath approximately 60 percent of the FJPS circumference. Because the test article was substantially different from flight configuration (no systems tunnel closeout), results of this test will not affect current flight motors. Due to the omission of systems tunnel covers and systems tunnel floor plate closeout, the test assembly was not representative of flight hardware and resulted in a gross overtest. It is therefore recommended that the test be declared void. It is also recommended that the test be repeated with a complete closeout of the systems tunnel, sealed systems tunnel ends, and improved adhesive bondline preparation.

  1. NDE of Space Shuttle Solid Rocket Motor field joint

    NASA Technical Reports Server (NTRS)

    Johnston, Patrick H.

    1987-01-01

    One of the most critical areas for inspection in the Space Shuttle Solid Rocket Motors is the bond between the steel case and rubber insulation in the region of the field joints. The tang-and-clevis geometry of the field joints is sufficiently complex to prohibit the use of resonance-based techniques. One approach we are investigating is to interrogate the steel-insulation bondline in the tang and clevis regions using surface-travelling waves. A low-frequency contact surface wave transmitting array transducer is under development at our laboratory for this purpose. The array is placed in acoustic contact with the steel and surface waves are launched on the inside surface or the clevis leg which propagate along the steel-insulation interface. As these surface waves propagate along the bonded surface, the magnitude of the ultrasonic energy leaking into the steel is monitored on the outer surface of the case. Our working hypothesis is that the magnitude of energy received at the outer surface of the case is dependent upon the integrity of the case-insulation bond, with less attenuation for propagation along a disbond due to imperfect acoustic coupling between the steel and rubber. Measurements on test specimens indicate a linear relationship between received signal amplitude and the length of good bend between the transmitter and receiver, suggesting the validity of this working hypothesis.

  2. Influence of Microstructure of Friction Stir Welded Joints on Growth and Properties of Microarc Oxidation Coatings on AZ31B Magnesium Alloy

    NASA Astrophysics Data System (ADS)

    Chen, Tingfang; Li, Yongliang; Xue, Wenbin; Yang, Chaolin; Qu, Yao; Hua, Ming

    2015-03-01

    Ceramic coatings on friction stir welded (FSW) joints of AZ31B magnesium alloy were fabricated by microarc oxidation (MAO) method in silicate electrolyte. Microstructure, phase constituents, microhardness and electrochemical corrosion behaviors of bare and coated magnesium alloys at different zones of FSW joints for different oxidation time were investigated. The influence of microstructure at different zones on the growth of MAO coatings was analyzed. The results show that the MAO coatings on FSW joints are uniform, and they have almost the same morphology, phase constituents, hardness and corrosion resistance at base metal, stir zone and heat-affected zone. The properties of MAO coatings are independent on the microstructures of AZ31B alloy. In addition, the microstructures of magnesium alloy near the coating/alloy interface at different zones of FSW joint was not changed by microarc discharge process.

  3. Diamond-like carbon coatings enhance the hardness and resilience of bearing surfaces for use in joint arthroplasty.

    PubMed

    Roy, M E; Whiteside, L A; Xu, J; Katerberg, B J

    2010-04-01

    The purpose of this study was to evaluate the potential of a hard diamond-like carbon (DLC) coating to enhance the hardness and resilience of a bearing surface in joint replacement. The greater hardness of a magnesium-stabilized zirconium (Mg-PSZ) substrate was expected to provide a harder coating-substrate composite microhardness than the cobalt-chromium alloy (CoCr) also used in arthroplasty. Three femoral heads of each type (CoCr, Mg-PSZ, DLC-CoCr and DLC-Mg-PSZ) were examined. Baseline (non-coated) and composite coating/substrate hardness was measured by Vickers microhardness tests, while nanoindentation tests measured the hardness and elastic modulus of the DLC coating independent of the Mg-PSZ and CoCr substrates. Non-coated Mg-PSZ heads were considerably harder than non-coated CoCr heads, while DLC coating greatly increased the microhardness of the CoCr and Mg-PSZ substrates. On the nanoscale the non-coated heads were much harder than on the microscale, with CoCr exhibiting twice as much plastic deformation as Mg-PSZ. The mechanical properties of the DLC coatings were not significantly different for both the CoCr and Mg-PSZ substrates, producing similar moduli of resilience and plastic resistance ratios. DLC coatings greatly increased hardness on both the micro and nano levels and significantly improved resilience and resistance to plastic deformation compared with non-coated heads. Because Mg-PSZ allows less plastic deformation than CoCr and provides a greater composite microhardness, DLC-Mg-PSZ will likely be more durable for use as a bearing surface in vivo. PMID:19861184

  4. Field Enhanced Thermionic Electron Emission from Oxide Coated Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Day, Christopher; Jin, Feng; Liu, Yan; Little, Scott

    2006-03-01

    We have created a novel nanostructure by coating carbon nanotubes with a thin functional oxide layer. The structure was fabricated by sputter deposition of a thin film of oxide materials on aligned carbon nanotubes, which were grown on a tungsten substrate with plasma enhanced chemical vapor deposition. This structure combines the low work function of the oxide coating with a high field enhancement factor introduced by carbon nanotubes and we have demonstrated that it can be used as a highly efficient electron source. A field enhancement factor as high as 2000 was observed and thermionic electron emission current at least an order of magnitude higher than the emission from a conventional oxide cathode was obtained.

  5. Surface treatment and surface coating of silicon field emitter array

    NASA Astrophysics Data System (ADS)

    Hajra, Mahua Sudhakrishna

    The objectives of this research were to fabricate ungated Si field emitter arrays (FEA's), and then to identify ways to improve the performance of the emitters. In the first and second chapters, the basis of the research, including background, theory, and the goals of the research is presented. The third chapter discusses the fabrication methods used to form the ungated Si FEA's. The fourth chapter gives the details about surface treatment procedures used to improve initial operation. The fifth and the sixth chapter discuss the different surface coating materials used to study the emission properties of the Si field emitters. The seventh chapter summarizes the work and suggests possible follow up research. The four surface treatments discussed in chapter four employ, respectively, residual gas ions, low-energy electron-stimulated desorption, a hydrogen-enhanced residual gas atmosphere, and a plasma of a Ar (96%) and H2 (4%) gas mixture. The method, using the hydrogen-enriched residual gas atmosphere is very unique in that it uses getters to produce the hydrogen rich atmosphere. The method, using a plasma of Ar (96%) and H2 (4%) gas mixture, is an effective in-situ cleaning procedure, which can be performed prior to packaging the devices. In chapters five and six is a comparison of the field-emission properties of the Si FEA coated with various materials, including (1) nanoparticle clusters of diamond and gallium nitride (GaN), (2) a thin film of ultrananocrystalline diamond (UNCD), (3) a lead zirconate titanate (PZT) coating, and (4) carbon nanotubes. Among the above coatings, the conformal coating of UNCD produced electron emission at an extremely low threshold field of between 2 to 5 V/mum. A further study of the behavior of electron emission from UNCD-coated Si FEA during in-situ exposure to H2, N2, and Ar respectively showed that when the emitting surface is exposed to H 2, at 10-5 Torr and 10-4 Torr, the initial emission current (2 muA) increases by a factor

  6. Field homogeneity improvement of maglev NdFeB magnetic rails from joints.

    PubMed

    Li, Y J; Dai, Q; Deng, C Y; Sun, R X; Zheng, J; Chen, Z; Sun, Y; Wang, H; Yuan, Z D; Fang, C; Deng, Z G

    2016-01-01

    An ideal magnetic rail should provide a homogeneous magnetic field along the longitudinal direction to guarantee the reliable friction-free operation of high temperature superconducting (HTS) maglev vehicles. But in reality, magnetic field inhomogeneity may occur due to lots of reasons; the joint gap is the most direct one. Joint gaps inevitably exist between adjacent segments and influence the longitudinal magnetic field homogeneity above the rail since any magnetic rails are consisting of many permanent magnet segments. To improve the running performance of maglev systems, two new rail joints are proposed based on the normal rail joint, which are named as mitered rail joint and overlapped rail joint. It is found that the overlapped rail joint has a better effect to provide a competitive homogeneous magnetic field. And the further structure optimization has been done to ensure maglev vehicle operation as stable as possible when passing through those joint gaps. The results show that the overlapped rail joint with optimal parameters can significantly reduce the magnetic field inhomogeneity comparing with the other two rail joints. In addition, an appropriate gap was suggested when balancing the thermal expansion of magnets and homogenous magnetic field, which is considered valuable references for the future design of the magnetic rails. PMID:27066380

  7. Anti-Relaxation Coatings at High Magnetic Field

    NASA Astrophysics Data System (ADS)

    Olsen, Ben; Happer, Will; Patton, Brian; Budker, Dmitry; Balabas, Mikhail

    2011-05-01

    Polarized alkali metal vapors are the basis for many technologies and experiments in atomic physics such as magnetometers, atomic clocks, precision measurements and spin exchange optical pumping (SEOP). These applications all rely on long relaxation times of the populations and coherences in the vapor, and considerable effort has been spent developing techniques to extend these times. The significant relaxation due to the glass walls of vapor cells can be drastically reduced by applying a coating of organic molecules such as paraffin to the cell's interior. To study the effects of anti-relaxation coatings on alkali vapors, we measured the ground-state populations of cesium vapor in coated vapor cells at high magnetic field. In this regime, each ground-state sublevel population can be individually measured with a weak D1 (S1 / 2 -->P1 / 2) laser while a stronger D2 (S1 / 2 -->P3 / 2) laser depopulates a single sublevel. We physically translated the probe beam to measure the populations at different distances from the wall of the vapor cell, over a range of pump laser frequencies. We also measured the longitudinal relaxation rates of the cesium populations in the coated vapor cells by monitoring absorption of the probe while modulating the pump laser intensity.

  8. CFD Simulations of Joint Urban Atmospheric Dispersion Field Study

    SciTech Connect

    Lee, R; Humphreys III, T; Chan, S

    2004-06-17

    The application of Computational Fluid Dynamics (CFD) to the understanding of urban wind flow and dispersion processes has gained increasing attention over recent years. While many of the simpler dispersion models are based on a set of prescribed meteorology to calculate dispersion, the CFD approach has the ability of coupling the wind field to dispersion processes. This has distinct advantages when very detailed results are required, such as for the case where the releases occur around buildings and within urban areas. CFD also has great flexibility as a testbed for turbulence models, which has important implications for atmospheric dispersion problems. In the spring of 2003, a series of dispersion field experiments (Joint Urban 2003) were conducted at Oklahoma City (Allwine, et. al, 2004). These experiments were complimentary to the URBAN 2000 field studies at Salt Lake City (Shinn, et. al, 2000) in that they will provide a second set of comprehensive field data for evaluation of CFD as well as for other dispersion models. In contrast to the URBAN 2000 experiments that were conducted entirely at night, these new field studies took place during both daytime and nighttime thus including the possibility of convective as well as stable atmospheric conditions. Initially several CFD modeling studies were performed to provide guidance for the experimental team in the selection of release sites and in the deployment of wind and concentration sensors. Also, while meteorological and concentration measurements were taken over the greater Oklahoma City urban area, our CFD calculations were focused on the near field of the release point. The proximity of the source to a large commercial building and to the neighboring buildings several of which have multistories, present a significant challenge even for CFD calculations involving grid resolutions as fine as 1 meter. A total of 10 Intensive Observations Periods (IOP's) were conducted within the 2003 field experiments. SF6

  9. Axisymmetric shell analysis of the space shuttle solid rocket booster field joint

    NASA Technical Reports Server (NTRS)

    Nemeth, Michael P.; Anderson, Melvin S.

    1991-01-01

    The Space Shuttle Challenger (STS 51-L) accident led to an intense investigation of the structural behavior of the solid rocket booster (SRB) tang and clevis field joints. Results are presented of axisymmetric shell analyses that parametrically assess the structural behavior of SRB field joints subjected to quasi-steady-state internal pressure loading for both the original joint flown on mission STS 51-L and the redesigned joint flown for the first time after the STS 51-L accident on the Space Shuttle Discovery. Discussion of axisymmetric shell modeling issues and details is presented and a generic method for simulating contact between adjacent shells of revolution is described. Results are presented that identify the performance trends of the joints for a wide range of joint parameters. An important finding is that the redesigned joint exhibits significantly smaller O-ring gap changes and much less sensitivity to joint clearances than the original joint. For a wide range of joint parameters, the result presented indicate that the redesigned joint provides a much better pressure seal than the original joint.

  10. Axisymmetric shell analysis of the Space Shuttle solid rocket booster field joint

    NASA Technical Reports Server (NTRS)

    Nemeth, Michael P.; Anderson, Melvin S.

    1989-01-01

    The Space Shuttle Challenger (STS 51-L) accident led to an intense investigation of the structural behavior of the solid rocket booster (SRB) tang and clevis field joints. The presence of structural deformations between the clevis inner leg and the tang, substantial enough to prevent the O-ring seals from eliminating hot gas flow through the joints, has emerged as a likely cause of the vehicle failure. This paper presents results of axisymmetric shell analyses that parametrically assess the structural behavior of SRB field joints subjected to quasi-steady-state internal pressure loading for both the original joint flown on mission STS 51-L and the redesigned joint recently flown on the Space Shuttle Discovery. Discussion of axisymmetric shell modeling issues and details is presented and a generic method for simulating contact between adjacent shells of revolution is described. Results are presented that identify the performance trends of the joints for a wide range of joint parameters.

  11. Electric-field-assisted convective assembly of colloidal crystal coatings.

    PubMed

    Kleinert, Jairus; Kim, Sejong; Velev, Orlin D

    2010-06-15

    A new technique that combines evaporative convective deposition of colloidal crystal coatings with an electric field to achieve more rapid assembly and reduce the defects in the crystal structure is reported. When an ac voltage is applied across the particle suspension and the substrate in the convective assembly process, a longer film spreads from the meniscus by the electrowetting-on-dielectric (EWOD) effect. The data suggest that the EWOD-increased liquid surface area results in increased evaporation-driven particle flux and crystal assembly that is up to five times more rapid. The extended drying film also provides more time for particle rearrangement before the structure becomes fixed, resulting in formation of crystal domains an order of magnitude larger than those deposited by convective assembly alone. The results demonstrate that EWOD is a facile tool for controlling particle assembly processes in wetting films. The technique could be used in improved large-scale colloidal crystal coating processes. PMID:20465234

  12. Abrasion resistance of oxidized zirconium in comparison with CoCrMo and titanium nitride coatings for artificial knee joints.

    PubMed

    Galetz, Mathias C; Fleischmann, Ernst W; Konrad, Christian H; Schuetz, Adelheid; Glatzel, Uwe

    2010-04-01

    Most total knee replacement joints consist of a metal femoral component made from a cobalt-chromium- molybdenum (CoCrMo)-alloy and a tibial component with an ultrahigh molecular weight polyethylene (UHMWPE) bearing surface. Wear of the UHMWPE remains the primary disadvantage of these implants. The allergic potential ascribed to CoCrMo-alloys is a further concern. Other metallic alloys with and without ceramic coatings are clinically used to avoid these problems. This study compared the mechanical surface properties of an oxidized zirconium alloy with those of cast and wrought CoCrMo and TiAlV6-4. Additionally, the influence of a titanium nitride (TiN)-plasma coating on the surface properties was investigated. The composition of the oxidized zirconium layer was analyzed. Micro- and macrohardness tests as well as adhesion tests were used to reveal material differences in terms of their abrasive wear potential in artificial joints. PMID:20162723

  13. Diamond-like carbon coatings enhance scratch resistance of bearing surfaces for use in joint arthroplasty: hard substrates outperform soft.

    PubMed

    Roy, Marcel E; Whiteside, Leo A; Katerberg, Brian J

    2009-05-01

    The purpose of this study was to test the hypotheses that diamond-like carbon (DLC) coatings will enhance the scratch resistance of a bearing surface in joint arthroplasty, and that a hard ceramic substrate will further enhance scratch resistance by reducing plastic deformation. We tested these hypotheses by applying a hard DLC coating to medical-grade cobalt chromium alloy (CoCr) and magnesia-stabilized zirconia (Mg-PSZ) femoral heads and performing scratch tests to determine the loads required to cause cohesive and adhesive fracture of the coating. Scratch tracks of DLC-coated and noncoated heads were then scanned by optical profilometry to determine scratch depth, width, and pile-up (raised edges), as measures of susceptibility to scratching. DLC-coated CoCr specimens exhibited cohesive coating fracture as wedge spallation at an average load of 9.74 N, whereas DLC-coated Mg-PSZ exhibited cohesive fracture as arc-tensile cracks and chipping at a significantly higher average load of 41.3 N (p < 0.0001). At adhesive coating fracture, DLC-CoCr delaminated at an average load of 35.2 N, whereas DLC-Mg-PSZ fractured by recovery spallation at a significantly higher average load of 46.8 N (p < 0.05). Both DLC-CoCr and DLC-Mg-PSZ specimens exhibited significantly shallower scratches and less pile-up than did uncoated specimens (p < 0.005 and p < 0.01, respectively). However, the harder ceramic substrate of DLC-Mg-PSZ better resisted plastic deformation, requiring significantly higher loads for cohesive and adhesive coating fracture. These findings supported both of our hypotheses. PMID:18985791

  14. Intractable sacroiliac joint pain treated with peripheral nerve field stimulation

    PubMed Central

    Chakrabortty, Shushovan; Kumar, Sanjeev; Gupta, Deepak; Rudraraju, Sruthi

    2016-01-01

    As many as 62% low back pain patients can have sacroiliac joint (SIJ) pain. There is limited (to poor) evidence in regards to long-term pain relief with therapeutic intra-articular injections and/or conventional (heat or pulsed) radiofrequency ablations (RFAs) for SIJ pain. We report our pain-clinic experience with peripheral nerve field stimulation (PNFS) for two patients of intractable SIJ pain. They had reported absence of long-term pain relief (pain relief >50% for at least 2 weeks postinjection and at least 3 months post-RFA) with SIJ injections and SIJ RFAs. Two parallel permanent 8-contact subcutaneous stimulating leads were implanted under the skin overlying their painful SIJ. Adequate stimulation in the entire painful area was confirmed. For implantable pulse generator placement, a separate subcutaneous pocket was made in the upper buttock below the iliac crest level ipsilaterally. During the pain-clinic follow-up period, the patients had reduced their pain medications requirements by half with an additional report of more than 50% improvement in their functional status. The first patient passed away 2 years after the PNFS procedure due to medical causes unrelated to his chronic pain. The second patient has been comfortable with PNFS-induced analgesic regimen during her pain-clinic follow-up during last 5 years. In summary, PNFS can be an effective last resort option for SIJ pain wherein conventional interventional pain techniques have failed, and analgesic medication requirements are escalating or causing unwarranted side-effects. PMID:27625495

  15. Intractable sacroiliac joint pain treated with peripheral nerve field stimulation.

    PubMed

    Chakrabortty, Shushovan; Kumar, Sanjeev; Gupta, Deepak; Rudraraju, Sruthi

    2016-01-01

    As many as 62% low back pain patients can have sacroiliac joint (SIJ) pain. There is limited (to poor) evidence in regards to long-term pain relief with therapeutic intra-articular injections and/or conventional (heat or pulsed) radiofrequency ablations (RFAs) for SIJ pain. We report our pain-clinic experience with peripheral nerve field stimulation (PNFS) for two patients of intractable SIJ pain. They had reported absence of long-term pain relief (pain relief >50% for at least 2 weeks postinjection and at least 3 months post-RFA) with SIJ injections and SIJ RFAs. Two parallel permanent 8-contact subcutaneous stimulating leads were implanted under the skin overlying their painful SIJ. Adequate stimulation in the entire painful area was confirmed. For implantable pulse generator placement, a separate subcutaneous pocket was made in the upper buttock below the iliac crest level ipsilaterally. During the pain-clinic follow-up period, the patients had reduced their pain medications requirements by half with an additional report of more than 50% improvement in their functional status. The first patient passed away 2 years after the PNFS procedure due to medical causes unrelated to his chronic pain. The second patient has been comfortable with PNFS-induced analgesic regimen during her pain-clinic follow-up during last 5 years. In summary, PNFS can be an effective last resort option for SIJ pain wherein conventional interventional pain techniques have failed, and analgesic medication requirements are escalating or causing unwarranted side-effects. PMID:27625495

  16. Space Shuttle production verification motor 1 (PV-1) field joint protection system, volume 7

    NASA Technical Reports Server (NTRS)

    Wilkinson, J. P.

    1990-01-01

    The performance of the field joint protection system (FJPS) of the Space Shuttle Production Verification Motor 1 (PV-1), as evaluated by postfire hardware inspection. Compliance with the specifications is shown for the FJPS assembly and components. The simplified FJPS and field joint heaters performed nominally, maintaining all joint seal temperatures within the required range. One anomally was noted on the igniter-to-case joint heater during postfire inspection. The heater buckled off the surface in two areas, resulting in two hot spots on the heater and darkened heater insulation. The condition did not affect heater performance during ignition countdown and all igniter seals were maintained within required temperature limits.

  17. Gold Coating of Fiber Tips in Near-Field Scanning Optical Microscopy

    NASA Technical Reports Server (NTRS)

    Vikram, Chandra S.; Witherow, William K.

    2000-01-01

    We report what is believed to be the first experimental demonstration of gold coating by a chemical baking process on tapered fiber tips used in near-field scanning optical microscopy. Many tips can be simultaneously coated.

  18. High-field thermal transport properties of REBCO coated conductors

    NASA Astrophysics Data System (ADS)

    Bonura, Marco; Senatore, Carmine

    2015-02-01

    The use of REBCO coated conductors (CCs) is envisaged for many applications, extending from power cables to high-field magnets. Whatever the case, thermal properties of REBCO tapes play a key role for the stability of superconducting devices. In this work, we present the first study on the longitudinal thermal conductivity (κ) of REBCO CCs in magnetic fields up to 19 T applied both parallel and perpendicularly to the thermal-current direction. Copper-stabilized tapes from six industrial manufacturers have been investigated. We show that zero-field κ of CCs can be calculated with an accuracy of +/- 15% from the residual resistivity ratio of the stabilizer and the Cu/non-Cu ratio. Measurements performed at high fields have allowed us to evaluate the consistency of the procedures generally used for estimating in-field κ in the framework of the Wiedemann-Franz law from an electrical characterization of the materials. In-field data are intended to provide primary ingredients for the thermal stability analysis of high-temperature superconductor-based magnets.

  19. A parametric shell analysis of the shuttle 51-L SRB AFT field joint

    NASA Technical Reports Server (NTRS)

    Davis, Randall C.; Bowman, Lynn M.; Hughes, Robert M., IV; Jackson, Brian J.

    1990-01-01

    Following the Shuttle 51-L accident, an investigation was conducted to determine the cause of the failure. Investigators at the Langley Research Center focused attention on the structural behavior of the field joints with O-ring seals in the steel solid rocket booster (SRB) cases. The shell-of-revolution computer program BOSOR4 was used to model the aft field joint of the solid rocket booster case. The shell model consisted of the SRB wall and joint geometry present during the Shuttle 51-L flight. A parametric study of the joint was performed on the geometry, including joint clearances, contact between the joint components, and on the loads, induced and applied. In addition combinations of geometry and loads were evaluated. The analytical results from the parametric study showed that contact between the joint components was a primary contributor to allowing hot gases to blow by the O-rings. Based upon understanding the original joint behavior, various proposed joint modifications are shown and analyzed in order to provide additional insight and information. Finally, experimental results from a hydro-static pressurization of a test rocket booster case to study joint motion are presented and verified analytically.

  20. Regional jointing and hydrocarbon generation in Big Sandy gas field, Kentucky

    SciTech Connect

    Loar, S.J.

    1986-05-01

    Producing wells in the Big Sandy gas field depend on well-developed subsurface joint systems to enhance migration into the borehole. To examine the joint systems, the surface joints were studied. Statistical analysis revealed eight regional joint sets: N30/sup 0/W, N10/sup 0/W, N20/sup 0/E, N30/sup 0/E, N40/sup 0/E, N60/sup 0/E, N80/sup 0/E, and east-west. These sets have the same orientations as reservoir joints observed in oriented cores, indicating that they are part of the same systems. Field observations suggest that the regional joint sets formed in at least three phases, which can be classified as hydraulic, tectonic, and unloading. The timing of hydrocarbons was calculated from a subsidence curve for Devonian and younger formations, which was constructed on the basis of published isopach, conodont alteration index, and well data. Plotting the maturation of the Ohio Shale with the regional jointing phases shows that the hydraulic joint sets formed before hydrocarbon generation began, and that the tectonic joint sets formed while the Ohio Shale was in the oil window. The oil and wet gas generated from the Ohio Shale have since migrated through the subsurface joint systems into younger reservoirs.

  1. Performance assessment and optimization of the ITER toroidal field coil joints

    NASA Astrophysics Data System (ADS)

    Rolando, G.; Foussat, A.; Knaster, J.; Ilin, Y.; Nijhuis, A.

    2013-08-01

    The ITER toroidal field (TF) system features eighteen coils that will provide the magnetic field necessary to confine the plasma. Each winding pack is composed of seven double pancakes (DP) connected through praying hands joints. Shaking hands joints are used to interface the terminals of the conductor with the feeder and inter-coil U-shaped bus bars. The feasibility of operating plasma scenarios depends on the ability of the magnets to retain sufficient temperature and current margins. In this respect, the joints represent a possible critical region due to the combination of steady state Joule heating in the resistance of the joint and coupling losses and currents in ramped operation. The temperature and current margins of both DP and terminal joints are analysed during the 15 and 17 MA plasma scenarios. The effect on the joint performance of feasible optimization solutions, such as rotation of the terminal joints and sole RRR increase, is explored. The characterization of the TF coil joints is completed by the estimation of the coupling loss time constant for different inter-strand and strand-to-joint resistance values. The study is carried out with the code JackPot-ACDC, allowing the analysis of lap-type joints with a strand-level detail.

  2. Flight set 360T004 (STS-30) field joint protection system, volume 7

    NASA Technical Reports Server (NTRS)

    Hale, Elgie

    1989-01-01

    The Redesigned Solid Rocket Motors (RSRM) of the Space Transportation System have three field joints that are protected by the Joint Protection Systems (JPS). The igniter heater was mounted on the igniter flange. This report documents the performance of the JPS and igniter heaters on the pad and the post-flight condition of the JPS components. All observations that were written up as Squawks and/or Problem Reports are also discussed. The primary heaters performed satisfactorily and maintained the field joint temperatures within the required temperature range. A secondary heater failed Dielectric Withstanding Voltage (DWV) test during the joint closeout prior to launch. This heater was not used, however, since the primary heater functioned properly. Post-test inspection revealed that pin A of the heater power cable was shorted to the connector shell. Design changes have been implemented to resolve the heater power cable problem. All field joint assemblies met all of the performance requirements.

  3. Structural optimization of an alternate design for the Space Shuttle solid rocket booster field joint

    NASA Technical Reports Server (NTRS)

    Barthelemy, Jean-Francois M.; Rogers, James L., Jr.; Chang, Kwan J.

    1987-01-01

    A structural optimization procedure is used to determine the shape of an alternate design for the Shuttle's solid rocket booster field joint. In contrast to the tang and clevis design of the existing joint, this alternate design consists of two flanges bolted together. Configurations with 150 studs of 1 1/8 in diameter and 135 studs of 1 3/16 in diameter are considered. Using a nonlinear programming procedure, the joint weight is minimized under constraints on either von Mises or maximum normal stresses, joint opening and geometry. The procedure solves the design problem by replacing it by a sequence of approximate (convex) subproblems; the pattern of contact between the joint halves is determined every few cycles by a nonlinear displacement analysis. The minimum weight design has 135 studs of 1 3/16 in diameter and is designed under constraints on normal stresses. It weighs 1144 lb per joint more than the current tang and clevis design.

  4. Structural optimization of an alternate design for the space shuttle solid rocket booster field joint

    NASA Technical Reports Server (NTRS)

    Barthelemy, J.-F. M.; Chang, K. J.; Rogers, J. L., Jr.

    1987-01-01

    A structural optimization procedure is used to determine the shape of an alternate design for the shuttle solid rocket booster field joint. In contrast to the tang and clevis design of the existing joint, this alternate design consists of two flanges bolted together. Configurations with 150 studs of 1 1/8 in. diameter and 135 studs of 1 3/16 in. diameter are considered. Using a nonlinear programming procedure, the joint weight is minimized under constraints on either von Mises or maximum normal stresses, joint opening and geometry. The procedure solves the design problem by replacing it by a sequence of approximate (convex) subproblems; the pattern of contact between the joint halves is determined every few cycles by a nonliner displacement analysis. The minimum weight design has 135 studs of 1 3/16 in. diameter and is designed under constraints on normal stresses. It weighs 1144 lb per joint more than the current tang and clevis design.

  5. Hexagonal Boron Nitride Coated Carbon Nanotubes: Interlayer Polarization Improved Field Emission.

    PubMed

    Chang, Han-Chen; Tsai, Hsin-Jung; Lin, Wen-Yi; Chu, Yung-Chi; Hsu, Wen-Kuang

    2015-07-01

    Coating of h-BN onto carbon nanotubes induces polarization at interfaces, and charges become localized at N and C atoms. Field emission of coated tubes is found to be highly stable, and current density fluctuates within 4%. Study further reveals that the electric field established between coatings and tubes facilitates charge transfer across interfaces and electrons are emitted through occupied and unoccupied bands of N and B atoms. PMID:26070100

  6. Scanning Hall probe measurements of field distributions of a coated conductor under applied fields

    NASA Astrophysics Data System (ADS)

    Yoo, Jaeun; Jung, Yonghwan; Lee, Jaeyoung; Lim, Sunme; Moo Lee, Sang; Jung, Ye Hyun; Youm, Dojun; Kim, Hosup; Ha, Hong Soo; Oh, Sangsoo

    2006-12-01

    We measured the field profiles near the surface of a coated conductor (CC) under various applied fields by using the scanning Hall probe method. The field, applied in the normal direction, was increased from zero to 171.5 Oe and then decreased to -58.8 Oe. We could not analyse our data completely by the direct use of Brandt's calculation but by a modification with unusual field dependences of the introduced parameters. Since Brandt's original calculation was based on homogeneous films, it was not suitable for CCs with coarse granular structures. The modified calculations with appropriate parameters are related to the coarse granular structures. Those parameters, D, Jc, and R, represent the three characteristics of the flux penetration network: the average distance of flux penetrations, the density of critical sheet currents, and the range of meandering of the flux penetration front, respectively. The external field dependences of these parameters were different from those of the classical critical state model.

  7. Optical properties of microfabricated fully-metal-coated near-field probes in collection mode.

    PubMed

    Descrovi, Emiliano; Vaccaro, Luciana; Aeschimann, Laure; Nakagawa, Wataru; Staufer, Urs; Herzig, Hans-Peter

    2005-07-01

    A study of the optical properties of microfabricated, fully-metal-coated quartz probes collecting longitudinal and transverse optical fields is presented. The measurements are performed by raster scanning the focal plane of an objective, focusing azimuthally and radially polarized beams by use of two metal-coated quartz probes with different metal coatings. A quantitative estimation of the collection efficiencies and spatial resolutions in imaging both longitudinal and transverse fields is made. Longitudinally polarized fields are collected with a resolution approximately 1.5 times higher as compared with transversely polarized fields, and this behavior is almost independent of the roughness of the probe's metal coating. Moreover, the coating roughness is a critical parameter in the relative collection efficiency of the two field orientations. PMID:16053165

  8. Final Report on Portable Laser Coating Removal Systems Field Demonstrations and Testing

    NASA Technical Reports Server (NTRS)

    Rothgeb, Matthew J.; McLaughlin, Russell L.

    2008-01-01

    Processes currently used throughout the National Aeronautics and Space Administration (NASA) to remove corrosion and coatings from structures, ground service equipment and small components results in waste streams consisting of toxic chemicals, spent media blast materials, and waste water. When chemicals are used in these processes they are typically high in volatile organic compounds (VOC) and are considered hazardous air pollutants (HAP). When blast media is used, the volume of hazardous waste generated is increased significantly. Many of the coatings historically used within NASA contain toxic metals such as hexavalent chromium, and lead. These materials are highly regulated and restrictions on worker exposure continue to increase. Most recently the EPA reduced the permissible exposure limit (PEL) for hexavalent chromium. The new standard lowers OSHA's PEL for hexavalent chromium from 52 to 5 micrograms of Cr(V1) per cubic meter of air as an 8-hour time-weighted average. Hexavalent chromium is found in the pretreatment and primer coatings used within the Shuttle Program. In response to the need to continue to protect assets within the agency and the growing concern over these new regulations, NASA is researching different ways to continue the required maintenance of both facility and flight equipment in a safe, efficient and environmentally preferable manner. The use of laser energy to remove prepare surfaces for a variety of processes, such as corrosion and coating removal, weld preparation and non destructive evaluation is a relatively new technology that has shown itself to be environmentally preferable and in many cases less labor intensive than currently used removal methods. The development of a Portable Laser Coating Removal System (PLCRS) started as the goal of a Joint Group on Pollution Prevention (JG-PP) project, led by the Air Force, where several types of lasers in several configurations were thoroughly evaluated. Following this project, NASA decided

  9. Diamond/diamond-like carbon coated nanotube structures for efficient electron field emission

    NASA Technical Reports Server (NTRS)

    Dimitrijevic, Steven (Inventor); Withers, James C. (Inventor); Loutfy, Raouf O. (Inventor)

    2005-01-01

    The present invention is directed to a nanotube coated with diamond or diamond-like carbon, a field emitter cathode comprising same, and a field emitter comprising the cathode. It is also directed to a method of preventing the evaporation of carbon from a field emitter comprising a cathode comprised of nanotubes by coating the nanotube with diamond or diamond-like carbon. In another aspect, the present invention is directed to a method of preventing the evaporation of carbon from an electron field emitter comprising a cathode comprised of nanotubes, which method comprises coating the nanotubes with diamond or diamond-like carbon.

  10. Atmospheric corrosion of coated steel; Relationship between laboratory and field testing

    NASA Astrophysics Data System (ADS)

    Cambier, Severine Marie Noelle

    The lifetime prediction for corrosion-protective coatings on metals is a challenge that has been studied for several decades. Accelerated tests are used in the hope to reproduce in few days the damage that would develop during several years of field exposure. Field exposures are also used because accelerated tests are not always reliable. Several approaches have been taken to reduce the duration of field exposures. One of them is the use of sensitive techniques to assess the coating degradation before visual inspection indicates any damage. Cathodic delamination measured by the scanning Kelvin probe (CD-SKP) was introduced here as a sensitive technique to assess the degradation at the coating/metal interface after weathering exposure. This technique was shown to predict the failure of the coating/steel interface. Several climates were tested in the US continent and on the islands of Hawaii. PVB coated steel environmental degradation was characterized in the field and reproduced in the laboratory. A second approach to shorten coated metal field exposure is to accelerate the degradation using intentionally added through-film scribes. In service, most corrosion mechanism for painted metals, such as filiform corrosion and cathodic delamination, initiate from a mechanical defect. The iron oxides formed under PVB and Eponol were identified with Raman spectroscopy to determine the environment factors that participated in their formation. This investigation was complemented by laboratory exposure. An accelerated test for PVB coated steel was designed to reproduce the environmental degradation observed in the field. The CD-SKP technique to assess interface degradation after weathering exposure was also applied to other coating systems. E-coated, sprayed epoxy primers with a conversion coating or grit blasting treatment, and one full coating system were tested.

  11. Polymer coating of glass microballoons levitated in a focused acoustic field

    NASA Technical Reports Server (NTRS)

    Young, A. T.; Lee, M. C.; Feng, I.-A.; Elleman, D. D.; Wang, T. G.

    1982-01-01

    Inertial confinement fusion (ICF) glass microballoons (GMBs) levitated in a focusing radiator acoustic device can be coated with liquid materials by deploying the liquid into the levitation field with a stepped-horn atomizer. The GMB can be forced to the center of the coating liquid with a strong acoustically generated centering force. Water solutions of organic polymers, UV-curable liquid organic monomers, and paraffin waxes have been used to prepare solid coatings on the surface of GMBs using this technique.

  12. Controlling electroosmotic flows by polymer coatings: A joint experimental-theoretical investigation

    NASA Astrophysics Data System (ADS)

    Monteferrante, Michele; Sola, Laura; Cretich, Marina; Chiari, Marcella; Marini Bettolo Marconi, Umberto; Melchionna, Simone

    2015-11-01

    We analyze the electroosmotic flow (EOF) of an electrolytic solution in a polymer coated capillary electrophoresis tube. The polymeric density, charge, thickness, and the capillary tube charge vary as a function of pH and produce a non-trivial modulation of the EOF, including a flow reversal at acid pH conditions. By means of a theoretical argument and numerical simulations, we recover the experimental curve for the EOF, providing a firm approach for predictive analysis of electroosmosis under different polymeric coating conditions. A proposed application of the approach is to determine the near-wall charge of the coating to be used for further quantitative analysis of the electroosmotic flow and mobility.

  13. Coatings.

    ERIC Educational Resources Information Center

    Anderson, Dennis G.

    1989-01-01

    This review covers analytical techniques applicable to the examination of coatings, raw materials, and substrates upon which coatings are placed. Techniques include chemical and electrochemical methods, chromatography, spectroscopy, thermal analysis, microscopy, and miscellaneous techniques. (MVL)

  14. Study on the pulse reverse electrodeposition of Fe-nano-Si composite coatings in magnetic field

    NASA Astrophysics Data System (ADS)

    Zhong, Yunbo; Zhou, Pengwei; Zhou, Junfeng; Wang, Huai; Fan, Lijun; Dong, Licheng; Zheng, Tianxiang; Shen, Weiwen

    2014-08-01

    Composite iron deposits containing nano-silicon particles were prepared under direct current (DCED) and pulse reverse current electrodeposition (PRED) conditions in the presence of magnetic field. The influences of magnetic field and pulse reverse current on the co-deposition of silicon particles as well as the surface morphology of coatings were investigated respectively. Results showed that PRED regime exhibits fewer incorporated silicon particles than those obtained under DCED condition when no magnetic field was applied. Under the influence of magnetic field, the silicon particles of coatings increased significantly, meanwhile, many projecting deposits named “mountain ranges” appeared on the surface of coatings. However, the numbers of “mountain ranges” showed a trend of reduce with increasing the pulse frequency under magnetic field and therefore the surface morphology of coatings became more smooth and flat.

  15. Joint and angle-covariant spin measurements with a quadrupole magnetic field

    NASA Technical Reports Server (NTRS)

    Martens, Hans; Demuynck, Willem M.

    1994-01-01

    We study a Stern-Gerlach type setup, with a quadrupole magnetic field, for neutral particles of arbitrary spin. The Hamiltonian is of a form proposed for joint measurements of the incompatible observables. The measurement results are discussed, showing the limitation of such Hamiltonians. Some remarks are made on the relevance of covariance as a criterion for measurement schemes.

  16. Test Data of Flow Field of Shuttle SRM Nozzle Joint with Bond Defects, Using Unheated Air

    NASA Technical Reports Server (NTRS)

    Hair, Leroy M.; McAnally, James V.; Hengel, John E.

    1989-01-01

    The nozzle-to-case joint on the Shuttle SRM (as redesigned after the Challenger accident) features an adhesive sealant filling and bonding the joint, with a wiper O-ring to prevent the adhesive from reaching and disabling the closure O-ring. Flawless implementation of that joint design would ensure that hot, corrosive propellant combustion gases never reach the closure O-ring. However, understanding the flow field related to bonding defects is prudent. A comprehensive test program was conducted to quantify such flow fields and associated heating environments. A two-dimensional, full-scale model represented 65 inches of the nozzle joint, using unheated air as the test medium, in a blowdown mode. Geometry variations modeled RSRM assembly tolerances, and two types of bonding defects: pullaways and blowholes. A range of the magnitude of each type defect was tested. Also a range of operational parameters was tested, representative of the RSRM flow environment, including duplication of RSRM Mach and Reynolds numbers. Extensive instrumentation was provided to quantify pressures, heat rates, and velocities. The resulting data established that larger geometric defects cause larger pressure and larger heating, at the closure O-ring region. Velocity trends were not so straight-forward. Variations in assembly tolerances did not generally affect flow fields or heating. Operational parameters affected flow fields and heating as might be expected, increasing density or velocity increased heating. Complete details of this test effort are presented.

  17. Electroless copper coating of epoxide plates in an ultrasonic field.

    PubMed

    Touyeras, F; Hihn, J Y; Doche, M L; Roizard, X

    2001-07-01

    This paper reports the study of ultrasonic irradiation effects on electroless copper coating on an epoxide resin. Several parameters were monitored, such as plating rates, practical adhesion and internal stress, versus varying acoustic powers at a constant frequency of 530 kHz. Exposure conditions were characterised by both transmitted power and interfacial mass transfer coefficients. Optimum conditions expressed in irradiation time and power were determined. The use of ultrasound during electroless copper plating affects the plating rates and the deposits properties, particularly the practical adhesion which increases whereas the internal stress decreases. Then, the changes in the coating mechanisms are discussed. PMID:11441612

  18. Practical field repair of fused slurry silicide coating for space shuttle t.p.s.

    NASA Technical Reports Server (NTRS)

    Reznik, B. D.

    1971-01-01

    Study of short-time high-temperature diffusion treatments as part of a program of development of methods of reapplying fused slurry silicide coating in the field. The metallographic structure and oxidation behavior of R512E applied to Cb-752 coated under simulated field repair conditions was determined. Oxidation testing in reduced pressure environment has shown that performance equivalent to furnace-processed specimens can be obtained in a two-minute diffusion at 2700 F.

  19. Biotribological behavior of Ag-ZrCxN1-x coatings against UHMWPE for joint prostheses devices.

    PubMed

    Calderon V, S; Sánchez-López, J C; Cavaleiro, A; Carvalho, S

    2015-01-01

    This study aims to evaluate the structural, mechanical and tribological properties of zirconium carbonitrides (ZrCxN1-x) coatings with embedded silver nanoparticles, produced with the intention of achieving a material with enhanced multi-functional properties, including mechanical strength, corrosion resistance, tribological performance and antibacterial behavior suitable for their use in joint prostheses. The coatings were deposited by direct current (DC) reactive magnetron sputtering onto 316 L stainless steel, changing the silver content from 0 to 20 at% by modifying the current density applied to the targets. Different nitrogen and acetylene gas fluxes were used as reactive gases. The coatings revealed different mixtures of crystalline ZrCxN1-x, silver nanoparticles and amorphous carbon phases. The hardness of the films was found to be mainly controlled by the ratio between the hard (ZrCxN1-x) and soft (Ag and amorphous carbon) phases in the films, fluctuating between 7.4 and 20.4 GPa. The coefficient of friction, measured against ultra-high molecular weight polyethylene (UHMWPE) in Hank's balanced salt solution with 10 gL(-1) albumin, is governed by the surface roughness and hardness. The UHMWPE wear rates were in the same order of magnitude (between 1.4 and 2.0 × 10(-6)mm(3)N(-1)m(-1)), justified by the effect of the protective layer of albumin formed during the tests. The small differences were due to the hydrophobic/hydrophilic character of the surface, as well as to the silver content. PMID:25460405

  20. The joint use of the tangential electric field and surface Laplacian in EEG classification.

    PubMed

    Carvalhaes, C G; de Barros, J Acacio; Perreau-Guimaraes, M; Suppes, P

    2014-01-01

    We investigate the joint use of the tangential electric field (EF) and the surface Laplacian (SL) derivation as a method to improve the classification of EEG signals. We considered five classification tasks to test the validity of such approach. In all five tasks, the joint use of the components of the EF and the SL outperformed the scalar potential. The smallest effect occurred in the classification of a mental task, wherein the average classification rate was improved by 0.5 standard deviations. The largest effect was obtained in the classification of visual stimuli and corresponded to an improvement of 2.1 standard deviations. PMID:23864444

  1. NATO TG-53: acoustic detection of weapon firing joint field experiment

    NASA Astrophysics Data System (ADS)

    Robertson, Dale N.; Pham, Tien; Scanlon, Michael V.; Srour, Nassy; Reiff, Christian G.; Sim, Leng K.; Solomon, Latasha; Thompson, Dorothea F.

    2006-05-01

    In this paper, we discuss the NATO Task Group 53 (TG-53) acoustic detection of weapon firing field joint experiment at Yuma Proving Ground during 31 October to 4 November 2005. The participating NATO countries include France, the Netherlands, UK and US. The objectives of the joint experiments are: (i) to collect acoustic signatures of direct and indirect firings from weapons such as sniper, mortar, artillery and C4 explosives and (ii) to share signatures among NATO partners from a variety of acoustic sensing platforms on the ground and in the air distributed over a wide area.

  2. Modeling and analysis of magnetic field distribution of square pane permanent magnet for intelligent ball joint

    NASA Astrophysics Data System (ADS)

    Zhu, Liang; Hu, Penghao; Yang, Wenguo; Dang, Xueming; Zhang, Lisong

    2016-01-01

    The reasonable permanent magnetic field distribution has an important influence on improving the measuring accuracy in intelligent ball joint. In view of the defects on the ring permanent magnet in the previous experiment scheme, a new method on Square Pane Permanent Magnet (SPPM) is put forward. It possesses distinct advantages on orientation identification and model simplification. This paper proposes an optimized theory model of the magnetic field distribution of SPPM and gives the magnetic field theoretical expressions. The experiments have shown that the experimental data basically agreed with the theory value which is less than 4.3% error in full scale. This result verified the correctness of the analytic work and paves the way for improving the measurement accuracy in intelligent ball joint.

  3. Circumferential flow analysis at the aft field joint of the Space Shuttle solid rocket motor

    NASA Technical Reports Server (NTRS)

    Majumdar, Alok K.; Whitesides, R. Harold; Jenkins, Susan L.; Bacchus, David L.

    1988-01-01

    Flow analyses have been performed to determine the nature of the three-dimensional flow field in the vicinity of the aft-most field joint of the Space Shuttle Redesigned Solid Rocket Motor (RSRM). Specific objectives included the quantification of the circumferential pressure and velocity gradients at the joint location which might be caused by the non-uniform erosion of the rubber inhibitor which protrudes from the wall into the flow field. Three-dimensional Navier-Stokes equations have been solved in conjunction with the conservation equation for the turbulence energy and the dissipation rate. The numerical predictions have been compared with the measurements from a 7.5 percent scale cold flow model of the redesigned solid rocket motor.

  4. Enhanced field emission from lanthanum hexaboride coated multiwalled carbon nanotubes: Correlation with physical properties

    SciTech Connect

    Patra, Rajkumar; Ghosh, S.; Sheremet, E.; Rodriguez, R. D.; Lehmann, D.; Zahn, D. R. T.; Jha, Menaka; Ganguli, A. K.; Schmidt, H.; Schulze, S.; Hietschold, M.; Schmidt, O. G.

    2014-10-28

    Detailed results from field emission studies of lanthanum hexaboride (LaB{sub 6}) coated multiwalled carbon nanotube (MWCNT) films, pristine LaB{sub 6} films, and pristine MWCNT films are reported. The films have been synthesized by a combination of chemical and physical deposition processes. An impressive increase in field enhancement factor and temporal stability as well as a reduction in turn-on field and threshold field are observed in LaB{sub 6}-coated MWCNTs compared to pristine MWCNT and pristine LaB{sub 6} films. Surface morphology of the films has been examined by scanning electron microscopy. Introduction of LaB{sub 6} nanoparticles on the outer walls of CNTs LaB{sub 6}-coated MWCNTs films is confirmed by transmission electron microscopy. The presence of LaB{sub 6} was confirmed by X-ray photoelectron spectroscopy results and further validated by the Raman spectra. Raman spectroscopy also shows 67% increase in defect concentration in MWCNTs upon coating with LaB{sub 6} and an upshift in the 2D band that could be attributed to p-type doping. Ultraviolet photoelectron spectroscopy studies reveal a reduction in the work function of LaB{sub 6}-coated MWCNT with respect to its pristine counterpart. The enhanced field emission properties in LaB{sub 6}-coated MWCNT films are correlated with a change in microstructure and work function.

  5. Multi-field coupled sensing network for health monitoring of composite bolted joint

    NASA Astrophysics Data System (ADS)

    Wang, Yishou; Qing, Xinlin; Dong, Liang; Banerjee, Sourav

    2016-04-01

    Advanced fiber reinforced composite materials are becoming the main structural materials of next generation of aircraft because of their high strength and stiffness to weight ratios, and excellent designability. As key components of large composite structures, joints play important roles to ensure the integrity of the composite structures. However, it is very difficult to analyze the strength and failure modes of composite joints due to their complex nonlinear coupling factors. Therefore, there is a need to monitor, diagnose, evaluate and predict the structure state of composite joints. This paper proposes a multi-field coupled sensing network for health monitoring of composite bolted joints. Major work of this paper includes: 1) The concept of multifunctional sensor layer integrated with eddy current sensors, Rogowski coil and arrayed piezoelectric sensors; 2) Development of the process for integrating the eddy current sensor foil, Rogowski coil and piezoelectric sensor array in multifunctional sensor layer; 3) A new concept of smart composite joint with multifunctional sensing capability. The challenges for building such a structural state sensing system and some solutions to address the challenges are also discussed in the study.

  6. Extension joints: a tool to infer the active stress field orientation (case study from southern Italy)

    NASA Astrophysics Data System (ADS)

    De Guidi, Giorgio; Caputo, Riccardo; Scudero, Salvatore; Perdicaro, Vincenzo

    2013-04-01

    An intense tectonic activity in eastern Sicily and southern Calabria is well documented by the differential uplift of Late Quaternary coastlines and by the record of the strong historical earthquakes. The extensional belt that crosses this area is dominated by a well established WNW-ESE-oriented extensional direction. However, this area is largely lacking of any structural analysis able to define the tectonics at a more local scale. In the attempt to fill this gap of knowledge, we carried out a systematic analysis of extension joint sets. In fact, the systematic field collection of these extensional features, coupled with an appropriate inversion technique, allows to determine the characteristic of the causative tectonic stress field. Joints are defined as outcrop-scale mechanical discontinuities showing no evidence of shear motion and being originated as purely extensional fractures. Such tectonic features are one of the most common deformational structures in every tectonic environment and particularly abundant in the study area. A particular arrangement of joints, called "fracture grid-lock system", and defined as an orthogonal joint system where mutual abutting and crosscutting relationships characterize two geologically coeval joint sets, allow to infer the direction and the magnitude of the tectonic stress field. We performed the analyses of joints only on Pleistocene deposits of Eastern Sicily and Southern Calabria. Moreover we investigated only calcarenite sediments and cemented deposits, avoiding claysh and loose matrix-supported clastic sediments where the deformation is generally accomodated in a distributed way through the relative motion between the single particles. In the selection of the sites, we also took into account the possibility to clearly observe the geometric relationships among the joints. For this reason we chose curvilinear road cuts or cliffs, wide coastal erosional surfaces and quarries. The numerical inversions show a similar stress

  7. Supporting the joint warfighter by development, training, and fielding of man-portable UGVs

    NASA Astrophysics Data System (ADS)

    Ebert, Kenneth A.; Stratton, Benjamin V.

    2005-05-01

    The Robotic Systems Pool (RSP), sponsored by the Joint Robotics Program (JRP), is an inventory of small robotic systems, payloads, and components intended to expedite the development and integration of technology into effective, supportable, fielded robotic assets. The RSP loans systems to multiple users including the military, first-responders, research organizations, and academia. These users provide feedback in their specific domain, accelerating research and development improvements of robotic systems, which in turn allow the joint warfighter to benefit from such changes more quickly than from traditional acquisition cycles. Over the past year, RSP assets have been used extensively for pre-deployment operator and field training of joint Explosive Ordnance Disposal (EOD) teams, and for the training of Navy Reservist repair technicians. These Reservists are part of the Robotic Systems Combat Support Platoon (RSCSP), attached to Space and Naval Warfare Systems Center, San Diego. The RSCSP maintains and repairs RSP assets and provides deployable technical support for users of robotic systems. Currently, a small team from the RSCSP is deployed at Camp Victory repairing and maintaining man-portable unmanned ground vehicles (UGVs) used by joint EOD teams in Operation Iraqi Freedom. The focus of this paper is to elaborate on the RSP and RSCSP and their role as invaluable resources for spiral development in the robotics community by gaining first-hand technical feedback from the warfighter and other users.

  8. Joint service lightweight standoff chemical agent detector reduced field-of-view

    NASA Astrophysics Data System (ADS)

    Popa, Mirela O.; Flanagan, Michael J.; Despard, V. Boyd; Griffin, Matthew T.; Engel, James R.

    2010-04-01

    A Reduced Field of View (RFOV) Fourier Transform Infrared (FTIR) system for standoff detection of chemical agents demonstrated improved detection at range during field testing. The RFOV system, from the original design parameter of 1.5 degree (27 milliradians) to 0.5 degrees (9 milliradians), includes novel modifications to the scanner assembly optical design to reduce the FOV without sacrificing existing radiometric sensitivity performance. The design modifications also allow for a straightforward retrofit of existing Joint Service Lightweight Standoff Chemical Agent Detectors (JSLSCAD). This paper will deliver an overview of the design and test results from field trials of the system as a function of range and environmental conditions.

  9. Joint reconstruction of non-overlapping magnetic particle imaging focus-field data.

    PubMed

    Knopp, T; Them, K; Kaul, M; Gdaniec, N

    2015-04-21

    The focus field is a key component to enable clinical applications in magnetic particle imaging (MPI). Due to physiological constraints, the method of choice is to place the focus of a small acquisition volume at various static positions in space and acquire the full field-of-view using a multi-station approach. In the first experiments, overlapping drive-field patches were used and boundary artifacts between drive-field patches were reduced using image processing. In this work we show that artifact-free reconstruction of non-overlapping focus-field data is feasible by using a joint reconstruction algorithm. This enables maximum scanning efficiency in multi-station focus-field experiments, which is key for reaching sufficiently short acquisition times to image the human heart. PMID:25803656

  10. Joint reconstruction of non-overlapping magnetic particle imaging focus-field data

    NASA Astrophysics Data System (ADS)

    Knopp, T.; Them, K.; Kaul, M.; Gdaniec, N.

    2015-04-01

    The focus field is a key component to enable clinical applications in magnetic particle imaging (MPI). Due to physiological constraints, the method of choice is to place the focus of a small acquisition volume at various static positions in space and acquire the full field-of-view using a multi-station approach. In the first experiments, overlapping drive-field patches were used and boundary artifacts between drive-field patches were reduced using image processing. In this work we show that artifact-free reconstruction of non-overlapping focus-field data is feasible by using a joint reconstruction algorithm. This enables maximum scanning efficiency in multi-station focus-field experiments, which is key for reaching sufficiently short acquisition times to image the human heart.

  11. Joint development and tectonic stress field evolution in the southeastern Mesozoic Ordos Basin, west part of North China

    NASA Astrophysics Data System (ADS)

    Jiang, Lin; Qiu, Zhen; Wang, Qingchen; Guo, Yusen; Wu, Chaofan; Wu, Zhijie; Xue, Zhenhua

    2016-09-01

    Major joint sets trending E-W (J1), ENE-WSW (J2), NE-SW (J3), N-S (J4), NNW-SSE (J5), NNE-SSW (J6), NW-SE (J7), and WNW-ESE (J8) respectively are recognized in Mesozoic strata within the southeast of Ordos Basin. Among them, the J1, J2 and J3 joint sets are systematic joints, while the other five joint sets (J4, J5, J6, J7, J8) are nonsystematic joints. There are three groups of orthogonal joint systems (i.e. J1 and J4 sets, J2 and J5 sets, and J6 and J8 sets) and two groups of conjugate shear fractures (ENE-WSW and NNE-SSW, ENE-WSW and ESE-WNW) in the study area. Joint spacing analysis indicates that: (1) layer thickness has an effect on the joint spacing, but the correlation of joint spacing and layer thickness is low; (2) joint density of systematic joints is greater than nonsystematic joints, and the joint density of a thin layer is also greater than that of a thick layer; and (3) the joints of Mesozoic strata in the basin are the result of tectonic events affected by multiple stress fields. All these joints in the Mesozoic strata are formed in the two main tectonic events since Late Mesozoic times. One is the westward subduction of the Pacific Plate beneath the Eurasia Plate, which formed the approximately E-W-trending compressive stress field in the China continent. The trends of the J1 joint set (E-W) and the bisector of conjugate shear fractures composed of ENE-WSW and ESE-WNW fractures are all parallel to the trend of maximum compressive stress (E-W). The other stress field is related to the collision of the Indian and Eurasian Plates, which formed the NE-SW-trending compressive stress field in the China continent. The trends of the J3 joint set and bisector of conjugate shear fractures composed of ENE-WSW and NNE-SSW fractures are all parallel to the trend of maximum compressive stress (NE-SW). Finally, we conclude that the J1 and J4 sets are formed in the E-W-trending compressive stress field, and the J2, J3, J5, J6, J7 and J8 sets are formed in the NE

  12. The effect of magnetic field on electrochemically deposited calcium phosphate/collagen coatings.

    PubMed

    Zhao, Xueni; He, Jianpeng; Zhang, Jing; Wang, Xudong; Wang, Wanying

    2014-01-01

    Nanostructured calcium phosphate/collagen (CaP/COL) coatings were deposited on the carbon/carbon (C/C) composites through electrochemical deposition (ECD) under magnetic field. The effect of magnetic fields with different orientations on the morphology and composition was investigated. Both the morphology and composition of the coatings could be altered by superimposed magnetic field. Under zero magnetic field and magnetic field, three-dimensional network structure consisting of collagen fibers and CaP were formed on the C/C substrate. The applied magnetic field in the electric field helped to form nanostructured and plate-like CaP on collagen fibers. For the ECD under magnetic field, the Ca/P molar ratio of the coatings was lower than the one under B=0. This may be contributed to the decreased electrical resistance or the increased electrical conductivity of electrolyte solutions under magnetic field. The nanosized CaP/COL coatings exhibited the similar morphology to the human bone and could present excellent cell bioactivity and osteoblast functions. PMID:25201398

  13. The fabrication of carbon-nanotube-coated electrodes and a field-emission-based luminescent device.

    PubMed

    Agarwal, Sanjay; Yamini Sarada, B; Kar, Kamal K

    2010-02-10

    Tungsten substrates were coated with an Ni or Ni-Co catalyst by the electroless dip coating technique. Various carbon nanotubes were synthesized by the catalytic chemical vapor deposition (CVD) method under different growth conditions. It was observed that Ni-and Ni-Co-coated tungsten substrates give very good growth of carbon nanotubes (CNT) in terms of yield, uniformity and alignment at a growth temperature of 600 degrees C. We fabricated a field-emission-based luminescent light bulb where a tungsten wire coated with carbon nanotubes served as a cathode. Results show lower threshold voltage, better emission stability and higher luminescence for CNT cathodes in comparison with uncoated tungsten cathodes. We found that aligned-coiled carbon nanotubes are superior to straight CNTs in terms of field emission characteristics and luminescence properties. PMID:20057034

  14. Effects of CaF2 Coating on the Microstructures and Mechanical Properties of Tungsten Inert Gas Welded AZ31 Magnesium Alloy Joints

    NASA Astrophysics Data System (ADS)

    Shen, Jun; Wang, Linzhi; Peng, Dong; Wang, Dan

    2012-11-01

    The effects of CaF2 coating on the macromorphologies of the welded seams were studied by morphological analysis. Microstructures and mechanical properties of butt joints welded with different amounts of CaF2 coatings were investigated using optical microscopy and tensile tests. The welding defects formed in the welded seams and the fracture surfaces were analyzed by scanning electron microscopy. An increase in the amount of CaF2 coating deteriorated the appearances of the welded seams but it improved the weld penetration depth and the depth/width ( D/ W) ratio of the tungsten inert gas (TIG) welded joints. The α-Mg grains and Mg17(Al,Zn)12 intermetallic compound (IMC) were coarser in the case of a higher amount of CaF2 coating. The increase in the amount of CaF2 coating reduced the porosities and total length of solidification cracks in the fusion zone (FZ). The ultimate tensile strength (UTS) value and elongation increased at first and then decreased sharply.

  15. Fabrication of PbS nanoparticle coated amorphous carbon nanotubes: Structural, thermal and field emission properties

    SciTech Connect

    Jana, S.; Banerjee, D.; Jha, A.; Chattopadhyay, K.K.

    2011-10-15

    Graphical abstract: Simple chemical synthesis of PbS nanoparticle coated amorphous carbon nanotubes have shown better thermal stability and enhanced electron field emission properties. Highlights: {yields} PbS nanocrystals coated amorphous carbon nanotubes have been synthesized through a simple chemical route at low temperature. {yields} The composite is thermally more stable than amorphous CNTs. {yields} Composite have shown excellent cold cathode field emission property. -- Abstract: A simple chemical route for the synthesis of PbS nanoparticle coated amorphous carbon nanotubes (aCNTs) was described. The nanocomposite was prepared from an aqueous suspension of acid functionalized aCNTs, lead acetate (PbAc), and thiourea (TU) at room temperature. The phase formation and composition of the samples were characterized by X-ray diffraction and energy dispersive analysis of X-ray studies. The Fourier transformed infrared spectra analysis revealed the attachment of PbS nanoparticles on the acid functionalized aCNT surfaces. Morphology of the samples was analyzed with a field emission scanning electron microscope. UV-Vis study also confirmed the attachment of PbS nanoparticles on the walls of aCNTs. Thermal gravimetric analysis showed that the PbS coated aCNTs are more thermally stable than functionalized aCNTs. The PbS coated aCNTs showed enhanced field emission properties with a turn-on field 3.34 V {mu}m{sup -1} and the result is comparable to that of pure crystalline CNTs.

  16. Preparation research of Nano-SiC/Ni-P composite coating under a compound field

    NASA Astrophysics Data System (ADS)

    Zhou, H. Z.; Wang, W. H.; Gu, Y. Q.; Liu, R.; Zhao, M. L.

    2016-07-01

    In this paper, the preparation process of Ni-P-SiC composite coatings on 45 steel surfaces with the assistance of magnetic and ultrasound fields was researched. The influence of external field on the surface morphology and performance of the composite layer is also discussed. Experimental results showed that when prepared under magnetic and ultrasonic fields, composite layers are significantly more dense and uniform than coatings made without external fields. Nano-SiC particles, dispersed uniformly in the layer, significantly improve the hardness of the composite layer, and the composite layer under the external field had the highest hardness at 680 HV The external fields can also accelerate deposition and increase the thickness of the layer. Compared to layers processed without the assistance of external fields, the thickness of the layers increased by nearly ten µm.

  17. A computer program to perform flow and thermal analysis during pressurization of the Space Shuttle Solid Rocket Motor field joint

    NASA Technical Reports Server (NTRS)

    Clayton, J. Louie; Colbert, R. F.; Ghaffarian, B.; Majumdar, Alok

    1991-01-01

    A computational technique for prediction of the flow and thermal environment in the SRM field joint cavities is described. The SRM field joint hardware was tested with a defect in the insulation, and due to this defect, the O-ring gland cavities are pressurized during the early part of the ignition. A computer model is developed to predict the thermal environment and flow through the simulated flaw, during the pressurization of the field joint. The transient mass, momentum, and energy conservation equations in the flow passage together with the thermodynamic equation of state are solved by a fully implicit iterative numerical procedure.

  18. Released Plasmonic Electric Field of Ultrathin Tetrahedral-Amorphous-Carbon Films Coated Ag Nanoparticles for SERS

    PubMed Central

    Liu, Fanxin; Tang, Chaojun; Zhan, Peng; Chen, Zhuo; Ma, Hongtao; Wang, Zhenlin

    2014-01-01

    We have demonstrated the plasmonic characteristics of an ultrathin tetrahedral amorphous carbon (ta-C) film coated with Ag nanoparticles. The simulation result shows that, under resonant and non-resonant excitations, the strongest plasmonic electric field of 1 nm ta-C coated Ag nanoparticle is not trapped within the ta-C layer but is released to its outside surface, while leaving the weaker electric field inside ta-C layer. Moreover, this outside plasmonic field shows higher intensity than that of uncoated Ag nanoparticle, which is closely dependent on the excitation wavelength and size of Ag particles. These observations are supported by the SERS measurements. We expect that the ability for ultrathin ta-C coated Ag nanoparticles as the SERS substrates to detect low concentrations of target biomolecules opens the door to the applications where it can be used as a detection tool for integrated, on-chip devices. PMID:24675437

  19. Thiokol/Wasatch installation evaluation of the redesigned field joint protection system (concepts 1 and 3)

    NASA Technical Reports Server (NTRS)

    Cook, M.

    1989-01-01

    The procedures, performance, and results obtained from the Thiokol Corporation/Wasatch Redesigned Field Joint Protection System (FJPS) Installation Evaluation are documented. The purpose of the evaluation was to demonstrate and develop the procedures required to install two different concepts (referred to as Concepts 1 and 3) of the redesigned FJPS. The processing capability of each configuration was then evaluated and compared. The FJPS is installed on redesigned solid rocket motors (RSRM) to protect the field joints from rain intrusion and to maintain the joint temperature sensor measurement between 85 and 122 F while the boosters are on the launch pad. The FJPS is being redesigned to reduce installation timelines at KSC and to simplify or eliminate installation processing problems related to the present design of an EPDM moisture seal/extruded cork combination. Several installation techniques were evaluated, and a preferred method of application was developed for each concept. The installations were performed with the test article in the vertical (flight) position. Comparative timelines between the two concepts were also developed. An additional evaluation of the Concept 3 configuration was performed with the test article in the horizontal position, to simulate an overhead installation on a technical evaluation motor (TEM).

  20. Thermal and electrical joint test for the helical field coils in the Advanced Toroidal Facility

    SciTech Connect

    Brown, R.L.; Johnson, R.L.

    1985-01-01

    Initial feasibility studies of a number of configurations for the Advanced Toroidal Facility (ATF) resulted in the selection of a resistive copper continuous-coil torsatron as the optimum device considering the physics program, cost, and schedule. Further conceptual design work was directed toward optimization of this configuration and, if possible, a shorter schedule. It soon became obvious that in order to shorten the schedule, a number of design and fabrication activities should proceed in parallel. This was most critical for the vacuum vessel and the helical field (HF) coils. If the HF coils were wound in place on a completed vacuum vessel, the overall schedule would be significantly (greater than or equal to12 months) longer. The approach of parallel scheduel paths requires that the HF coils be segmented into parts of less than or equal to180 of poloidal angle and that joints be made on a turn-by-turn basis when the segments are installed. It was obvious from the outset that the compact and complex geometry of the joint design presented a special challenge in the areas of reliability, assembly, maintenance, disassembly, and cost. Also, electrical, thermal, and force excursions are significant for these joints. A number of soldered, welded, brazed, electroplated, and bolted joints were evaluated. The evaluations examined fabrication feasibility and complexity, thermal-electrical performance at approximately two-thirds of the steady-state design conditions, and installation and assembly processes. Results of the thermal-electrical tests were analyzed and extrapolated to predict performance at peak design parameters. The final selection was a lap-type joint clamped with insulated bolts that pass through the winding packing. 3 refs., 4 figs.

  1. Magnetic Field Measurements Based on Terfenol Coated Photonic Crystal Fibers

    PubMed Central

    Quintero, Sully M. M.; Martelli, Cicero; Braga, Arthur M. B.; Valente, Luiz C. G.; Kato, Carla C.

    2011-01-01

    A magnetic field sensor based on the integration of a high birefringence photonic crystal fiber and a composite material made of Terfenol particles and an epoxy resin is proposed. An in-fiber modal interferometer is assembled by evenly exciting both eigenemodes of the HiBi fiber. Changes in the cavity length as well as the effective refractive index are induced by exposing the sensor head to magnetic fields. The magnetic field sensor has a sensitivity of 0.006 (nm/mT) over a range from 0 to 300 mT with a resolution about ±1 mT. A fiber Bragg grating magnetic field sensor is also fabricated and employed to characterize the response of Terfenol composite to the magnetic field. PMID:22247655

  2. Measurement of the light-field amplitude-correlation function through joint photon-count distributions.

    NASA Technical Reports Server (NTRS)

    Furcinitti, P.; Kuppenheimer, J. D.; Narducci, L. M.; Tuft , R. A.

    1972-01-01

    When an amplitude-stabilized He-Ne laser beam is scattered by a rotating ground glass with small surface inhomogeneities, the probability density of the instantaneous scattered-wave amplitude is Gaussian. In this paper, we suggest the use of the joint photon-count probability distribution to measure the absolute value of the electric-field amplitude-correlation function for random Gaussian light fields, and report the results of an experiment in which the Gaussian field is produced by scattering a light beam through a rotating ground glass. This procedure offers an alternative to other conventional methods, such as self-beating spectroscopy and irradiance-correlation techniques. The correlation time of the scattered-field amplitude in the present experiment has been measured with an accuracy of approximately 0.8%.

  3. Assessment of S-phase coated medical grade stainless steel (Ortron 90) for use in the human joint replacement corrosion wear environment

    NASA Astrophysics Data System (ADS)

    Dearnley, P. A.; Figueiredo Pina, C. G.; Fisher, J.

    2008-05-01

    Hard and corrosion resistant coating materials such as S-phase, a nitrogen supersaturated Fe-Ni-Cr-Mo phase, have the potential to limit the corrosion-wear (tribo-corrosion) damage that can affect the metallic bearing surfaces of joint replacement devices in vivo, but hitherto have not been much investigated. To test their suitability, a range of S-phase coatings (with five nitrogen concentrations [N]) was applied to several polished Ortron 90 (biomedical grade austenitic stainless steel) test pieces via magnetron sputter deposition. Crevice attack, via intergranular corrosion, was found to be worse for most S-phase coated and uncoated Ortron 90 materials when tested in bovine serum compared with testing in 0.89% NaCl solution. Measurements of the breakdown potentials and the anodic passive current density, for a given test solution, revealed the crevice corrosion response of uncoated Ortron 90 to be more severe than the S-phase coated materials, although this was not unequivocally supported by 2D profilometry measurements. Corrosion-wear tests made using a sliding contact Al2O3 counterface showed the surface degradation to be more aggressive in saline solution than in bovine serum. All S-phase coatings were very effective in mitigating corrosion-wear of Ortron 90 in bovine serum solution, but only one S-phase coating composition, containing 21 at% N, gave improved resistance when tested in 0.89% NaCl solution.

  4. The 1995 revision of the joint US/UK geomagnetic field models. II: Main field

    USGS Publications Warehouse

    Quinn, J.M.; Coleman, R.J.; Macmillan, S.; Barraclough, D.R.

    1997-01-01

    This paper presents the 1995 main-field revision of the World Magnetic Model (WMM-95). It is based on Project MAGNET high-level (??? 15,000 ft.) vector aeromagnetic survey data collected between 1988 and 1994 and on scalar total intensity data collected by the Polar Orbiting Geomagnetic Survey (POGS) satellite during the period 1991 through 1993. The spherical harmonic model produced from these data describes that portion of the Earth's magnetic field generated internal to the Earth's surface at the 1995.0 Epoch. When combined with the spherical harmonic model of the Earth's secular variation described in paper I, the Earth's main magnetic field is fully characterized between the years 1995 and 2000. Regional magnetic field models for the conterminous United States, Alaska and, Hawaii were generated as by-products of the global modeling process.

  5. Joint Estimation of Water/Fat Images and Field Inhomogeneity Map

    PubMed Central

    Hernando, D.; Haldar, J. P.; Sutton, B. P.; Ma, J.; Kellman, P.; Liang, Z.-P.

    2012-01-01

    Water/fat separation in the presence of B0 field inhomogeneity is a problem of considerable practical importance in MRI. This article describes two complementary methods for estimating the water/fat images and the field inhomogeneity map from Dixon-type acquisitions. One is based on variable projection (VARPRO) and the other on linear prediction (LP). The VARPRO method is very robust and can be used in low signal-to-noise ratio conditions because of its ability to achieve the maximum-likelihood solution. The LP method is computationally more efficient, and is shown to perform well under moderate levels of noise and field inhomogeneity. These methods have been extended to handle multicoil acquisitions by jointly solving the estimation problem for all the coils. Both methods are analyzed and compared and results from several experiments are included to demonstrate their performance. PMID:18306409

  6. Final Report on NASA Portable Laser Coating Removal Systems Field Demonstrations and Testing

    NASA Technical Reports Server (NTRS)

    Rothgeb, Matthew J; McLaughlin, Russell L.

    2008-01-01

    Portable Laser Coating Removal System (PLCRS) started as the goal of a Joint Group on Pollution Prevention (JG-PP) project, led by the Air Force, where several types of lasers in several configurations were thoroughly evaluated. Following this project, NASA decided to evaluate the best performers on processes and coatings specific to the agency. Laser systems used during this project were all of a similar design, between 40 and 500 Watts, most of which had integrated vacuum systems in order to collect materials removed from substrate surfaces during operation.

  7. Nitrous Oxide Gas Fluxes in a Potato Field Following Application of Urea and Coated Urea Fertilizers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Application of urea and other forms of nitrogen (N) fertilizer can generate atmospheric emissions of nitrous oxide (N2O), which is a potent greenhouse gas. Field experiments were conducted on a loamy sand soil in Becker, Minnesota to evaluate the effects of soluble and coated forms of urea on N2O fl...

  8. Comparisons between laser damage and optical electric field behaviors for hafnia/silica antireflection coatings

    SciTech Connect

    Bellum, John; Kletecka, Damon; Rambo, Patrick; Smith, Ian; Schwarz, Jens; Atherton, Briggs

    2011-03-20

    We compare designs and laser-induced damage thresholds (LIDTs) of hafnia/silica antireflection (AR) coatings for 1054 nm or dual 527 nm/1054 nm wavelengths and 0 deg. to 45 deg. angles of incidence (AOIs). For a 527 nm/1054 nm, 0 deg. AOI AR coating, LIDTs from three runs arbitrarily selected over three years are {approx}20 J/cm{sup 2} or higher at 1054 nm and <10 J/cm{sup 2} at 527 nm. Calculated optical electric field intensities within the coating show two intensity peaks for 527 nm but not for 1054 nm, correlating with the lower (higher) LIDTs at 527 nm (1054 nm). For 1054 nm AR coatings at 45 deg. and 32 deg. AOIs and S and P polarizations (Spol and Ppol), LIDTs are high for Spol (>35 J/cm{sup 2}) but not as high for Ppol (>30 J/cm{sup 2} at 32 deg. AOI; {approx}15 J/cm{sup 2} at 45 deg. AOI). Field intensities show that Ppol discontinuities at media interfaces correlate with the lower Ppol LIDTs at these AOIs. For Side 1 and Side 2 dual 527 nm/1054 nm AR coatings of a diagnostic beam splitter at 22.5 deg. AOI, Spol and Ppol LIDTs (>10 J/cm{sup 2} at 527 nm; >35 J/cm{sup 2} at 1054 nm) are consistent with Spol and Ppol intensity behaviors.

  9. Enhanced giant magnetoimpedance effect and field sensitivity in Co-coated soft ferromagnetic amorphous ribbons

    NASA Astrophysics Data System (ADS)

    Laurita, Nicholas; Chaturvedi, Anurag; Bauer, Christopher; Jayathilaka, Priyanga; Leary, Alex; Miller, Casey; Phan, Manh-Huong; McHenry, Michael E.; Srikanth, Hariharan

    2011-04-01

    A 50 nm-thick Co film has been grown either on the free surface (surface roughness, ˜6 nm) or on the wheel-side surface (surface roughness, ˜147 nm) of Co84.55Fe4.45Zr7B4 amorphous ribbons. A comparative study of the giant magnetoimpedance (GMI) effect and its field sensitivity (η) in the uncoated and Co-coated ribbons is presented. We show that the presence of the Co coating layer enhances both the GMI ratio and η in the Co-coated ribbons. Larger values for GMI ratio and η are achieved in the sample with Co coated on the free ribbon surface. The enhancement of the GMI effect in the Co-coated ribbons originates mainly from the reduction in stray fields due to surface irregularities and the enhanced magnetic flux paths closure. These findings provide good guidance for tailoring GMI in surface-modified soft ferromagnetic ribbons for use in highly sensitive magnetic sensors.

  10. The effects of surface and interface structure on field electron from diamond coatings

    SciTech Connect

    Choi, W.; Myers, A.; Cuomo, J.; Hren, J.

    1996-12-31

    A number of investigators have reported that coating silicon and metal substrates with several forms of diamond has led to significant improvement in the electron emission properties. The authors restrict this report to the effects on field electron emission from needle-shaped substrates before and after coating. Several forms of diamond and the influence of subsequent surface and thermal treatments were investigated. Needle shaped emitters were chosen because the same specimen could be extensively characterized by conventional Field Emitters methods before and after coating and/or after each subsequent treatment. The emitters are also conveniently shaped for detailed electron microscopic studies of the same interface and coating microstructure through which the emitted electrons must be supplied from the substrate. The substrates studied include: silicon, molybdenum, and nickel; diamond coatings were performed by: plasma CVD using bias enhanced nucleation and other nucleation techniques, as well as by dielectrophoresis, using different powders and thermal treatments. Surface treatments by O{sub 2} and Cs were also investigated, as were several environmental ambients (including H{sub 2} and D{sub 2}). Thermal treatment of the powders, after dielectrophoretic deposition was also studied in an attempt to maximize emission while retaining optimal stability.

  11. Multi-layer carbon-based coatings for field emission

    DOEpatents

    Sullivan, John P.; Friedmann, Thomas A.

    1998-01-01

    A multi-layer resistive carbon film field emitter device for cold cathode field emission applications. The multi-layered film of the present invention consists of at least two layers of a conductive carbon material, preferably amorphous-tetrahedrally coordinated carbon, where the resistivities of adjacent layers differ. For electron emission from the surface, the preferred structure can be a top layer having a lower resistivity than the bottom layer. For edge emitting structures, the preferred structure of the film can be a plurality of carbon layers, where adjacent layers have different resistivities. Through selection of deposition conditions, including the energy of the depositing carbon species, the presence or absence of certain elements such as H, N, inert gases or boron, carbon layers having desired resistivities can be produced.

  12. Multi-layer carbon-based coatings for field emission

    DOEpatents

    Sullivan, J.P.; Friedmann, T.A.

    1998-10-13

    A multi-layer resistive carbon film field emitter device for cold cathode field emission applications is disclosed. The multi-layered film of the present invention consists of at least two layers of a conductive carbon material, preferably amorphous-tetrahedrally coordinated carbon, where the resistivities of adjacent layers differ. For electron emission from the surface, the preferred structure can be a top layer having a lower resistivity than the bottom layer. For edge emitting structures, the preferred structure of the film can be a plurality of carbon layers, where adjacent layers have different resistivities. Through selection of deposition conditions, including the energy of the depositing carbon species, the presence or absence of certain elements such as H, N, inert gases or boron, carbon layers having desired resistivities can be produced. 8 figs.

  13. Magnetic field sensor based on fiber taper coupler coated with magnetic fluid

    NASA Astrophysics Data System (ADS)

    Lin, Wei; Zhang, Hao; Song, Binbin; Liu, Bo; Lin, Yandong; Liu, Haifeng; Miao, Yinping; Liu, Yange

    2015-09-01

    In this paper, we have demonstrated a magnetic field sensor based on the fiber taper coupler coated with Magnetic fluid. The proposed sensor is fabricated by immersing a fiber taper coupler into the Magnetic fluid and then sealing it with the paraffin. The sensor exhibits high response as a function of the magnetic field with sensitivities of 0.154 nm/Oe with measurement range from 50 Oe to 200 Oe and -0.06301 dB/ Oe from 75 Oe to 200 Oe. Owing to the advantages of high sensitivity, small footprint, and ease of fabrication, the proposed sensor would find potential applications in magnetic field sensing field.

  14. Magnetic flux penetration into twisted multifilamentary coated superconductors subjected to ac transverse magnetic fields

    NASA Astrophysics Data System (ADS)

    Amemiya, Naoyuki; Sato, Susumu; Ito, Takeshi

    2006-12-01

    ac losses in superconductors are generated by the magnetic flux and current penetration into them. To reveal the magnetic flux and current penetration processes in twisted multifilamentary coated superconductors in which the thin superconductor layer is subdivided into filaments and then twisted as a whole for ac loss reduction, a theoretical model for electromagnetic field analysis was developed based on the power law E-J (electric-field-current-density) characteristic for the superconductor and a thin strip approximation of the conductor. The developed theoretical model was implemented into a numerical code using the finite element method to calculate and visualize the current and magnetic flux distributions. The magnetization losses in twisted multifilamentary coated superconductors exposed to ac transverse magnetic fields were calculated from the temporal evolutions of the current distribution to demonstrate the effect of the twisted multifilamentary architecture on ac loss reduction.

  15. Results of field application and laboratory testing of thermal spray UNS N10276 coating for sour amine vessels

    SciTech Connect

    Baron, J.J.; Hay, M.G.; Goerz, K.G.; Schubert, R.W.; Easterly, F.B.

    1998-12-31

    The Caroline sour gas processing plant pressure vessels were constructed of bare carbon-manganese steel. Early detection of internal surface corrosion and hydrogen blistering led to a decision to field-apply a UNS N10276 coating. The dual-wire arc-spray technique was chosen following a careful review of the technical merits and costs of the alternatives. It was used to coat portions of eight vessels during a planned plant turnaround in 1995. A laboratory program was subsequently initiated in order to define the coating`s corrosion resistance and its effectiveness in preventing corrosion of, and hydrogen damage to, the steel substrate. This program examined the effect of variations in coating thickness and coverage, and steel substrate surface topography on coating performance in simulated rich amine (plant) and standard NACE International sour environments. In addition, an effective field repair procedure was qualified. The results of the inspection of the coating in three vessels after eighteen months` service justified the selection of the coating material and application technique. Only minor repairs to the coating in one vessel were required. This paper gives the results of the laboratory program and plant inspections, and provides guidelines for the application of thermal spray coatings in the field.

  16. Durability and shielding performance of borated Ceramicrete coatings in beta and gamma radiation fields

    NASA Astrophysics Data System (ADS)

    Wagh, Arun S.; Sayenko, S. Yu.; Dovbnya, A. N.; Shkuropatenko, V. A.; Tarasov, R. V.; Rybka, A. V.; Zakharchenko, A. A.

    2015-07-01

    Ceramicrete™, a chemically bonded phosphate ceramic, was developed for nuclear waste immobilization and nuclear radiation shielding. Ceramicrete products are fabricated by an acid-base reaction between magnesium oxide and mono potassium phosphate. Fillers are used to impart desired properties to the product. Ceramicrete's tailored compositions have resulted in several commercial structural products, including corrosion- and fire-protection coatings. Their borated version, called Borobond™, has been studied for its neutron shielding capabilities and is being used in structures built for storage of nuclear materials. This investigation assesses the durability and shielding performance of borated Ceramicrete coatings when exposed to gamma and beta radiations to predict the composition needed for optimal shielding performance in a realistic nuclear radiation field. Investigations were conducted using experimental data coupled with predictive Monte Carlo computer model. The results show that it is possible to produce products for simultaneous shielding of all three types of nuclear radiations, viz., neutrons, gamma-, and beta-rays. Additionally, because sprayable Ceramicrete coatings exhibit excellent corrosion- and fire-protection characteristics on steel, this research also establishes an opportunity to produce thick coatings to enhance the shielding performance of corrosion and fire protection coatings for use in high radiation environment in nuclear industry.

  17. Probing Emissions of Military Cargo Aircraft: Description of a Joint Field Measurement Program

    SciTech Connect

    Cheng, Mengdawn; Corporan, E.; DeWitt, M.; Spicer, C.; Holdren, M.; Cowen, K.; Harris, B.; Shores, R.; Hashmonay, R.; Kaganan, R.

    2008-01-01

    Direct emissions of NOx, volatile organic compounds, and particulate matter (PM) by aircraft contribute to the pollutant levels found in the atmosphere. Aircraft emissions can be injected at the ground level or directly at the high altitude in flight. Conversion of the precursor gases into secondary PM is one of the pathways for the increased atmospheric PM. Atmospheric PM interacts with solar radiation altering atmospheric radiation balance and potentially contributing to global and regional climate changes. Also, direct emissions of air toxics, ozone precursors and PM from aircraft in and around civilian airports and military air bases can worsen local air quality in non-attainment and/or maintenance areas. These emissions need to be quantified. However, the current EPA methods for particle emission measurements from such sources, modified Method 5 and Conditional Test Method 039, are gravimetric-based, and it is anticipated that these methods will not be suitable for current and future generations of aircraft turbine engines, whose particle mass emissions are low. To evaluate measurement approaches for military aircraft emissions, two complementary projects were initiated in 2005. A joint field campaign between these two programs was executed during the first week of October 2005 at the Kentucky Air National Guard (KYANG) base in Louisville, KY. This campaign represented the first in a series of field studies for each program funded by the DoD Strategic Environmental Research and Development Program (SERDP) and provided the basis for cross-comparison of the sampling approaches and measurement techniques employed by the respective program teams. This paper describes the overall programmatic of the multi-year SERDP aircraft emissions research and presents a summary of the results from the joint field campaign.

  18. Influences of surface coating, UV irradiation and magnetic field on the algae removal using magnetite nanoparticles.

    PubMed

    Ge, Shijian; Agbakpe, Michael; Wu, Zhiyi; Kuang, Liyuan; Zhang, Wen; Wang, Xianqin

    2015-01-20

    Magnetophoretic separation is a promising and sustainable technology for rapid algal separation or removal from water. This work demonstrated the application of magnetic magnetite nanoparticles (MNPs) coated with a cationic polymer, polyethylenimine (PEI), toward the separation of Scenedesmus dimorphus from the medium broth. The influences of surface coating, UV irradiation, and magnetic field on the magnetophoretic separation were systematically examined. After PEI coating, zeta potential of MNPs shifted from −7.9 ± 2.0 to +39.0 ± 3.1 mV at a pH of 7.0, which improved MNPs-algae interaction and helped reduce the dose demand of MNPs (e.g., from 0.2 to 0.1 g·g(–1) while the harvesting efficiency (HE) of over 80% remained unchanged). The extended Derjaguin–Landau–Verwey–Overbeek theory predicted a strong attractive force between PEI-coated MNPs and algae, which supported the improved algal harvesting. Moreover, the HE was greater under the UV365 irradiation than that under the UV254, and increased with the irradiation intensity. Continuous application of the external magnetic field at high strength remarkably improved the algal harvesting. Finally, the reuse of MNPs for multiple cycles of algal harvesting was studied, which aimed at increasing the sustainability and lowering the cost. PMID:25486124

  19. Joint Instability of Differential Rotation and Toroidal Magnetic Fields below the Solar Convection Zone, II

    NASA Astrophysics Data System (ADS)

    Gilman, P. A.; Fox, P.

    1997-05-01

    At the 1996 AAS/SPD meeting in Madison we reported first results for the joint instability of differential rotation and toroidal magnetic fields to 2D disturbances (see also Gilman and Fox, Paper I, July 20 1997 issue of ApJ). This analysis was for the toroidal field profile B=a*sin(LAT)cos(LAT). This paper reports results for the profile B=(a*sin(LAT)+b*(sin(LAT))(3) ))cos(LAT), which, with b<-a<0, allows for a node in the toroidal field at latitude arcsin (-a/b). This generalization is of interest because we should expect such a node to appear and migrate equatorward as the sun proceeds from one sunspot cycle to the next. As with the simpler profile, instability occurs for virtually all differential rotation amplitudes, and all toroidal field amplitudes and shapes, and remains confined to disturbances with longitudinal wave number m=1. For a, b>0, the instability is enhanced for the same a compared to the b=0 case, particularly in high latitudes. For 0>b>-a (so no node is present) the instability is similar to the b=0 case but with diminished growth rates, due to the reduction of toroidal fields at high latitudes. At b=-a, the symmetric mode of instability vanishes, but the antisymmetric mode remains. For b<-a<0, both symmetric and antisymmetric modes are unstable, but with disturbances confined largely to the domain poleward of the node, unless the toroidal field energy greatly exceeds the kinetic energy of differential rotation. Unstable disturbances spread and migrate toward the equator as the field strength is increased and as the node is moved equatorward. Thus, the instability may still contribute to the existence of the solar butterfly diagram, and to other solar dynamo presses.

  20. Dynamic Resistance of YBCO-Coated Conductors in Applied AC Fields with DC Transport Currents and DC Background Fields

    SciTech Connect

    Duckworth, Robert C; Zhang, Yifei; Ha, Tam T; Gouge, Michael J

    2011-01-01

    In order to predict heat loads in future saturable core fault-current-limiting devices due to ac fringing fields, dynamic resistance in YBCO-coated conductors was measured at 77 K in peak ac fields up to 25 mT at 60 Hz and in dc fields up to 1 T. With the sample orientation set such that the conductor face was either parallel or perpendicular to the ac and dc applied fields, the dynamic resistance was measured at different fractions of the critical current to determine the relationship between the dc transport current and the applied fields. With respect to field orientation, the dynamic resistance for ac fields that were perpendicular to the conductor face was significantly higher than when the ac fields were parallel to the conductor face. It was also observed that the dynamic resistance: (1) increased with increasing fraction of the dc transport current to the critical current, (2) was proportional to the inverse of the critical current, and (3) demonstrated a linear dependence with the applied ac field once a threshold field was exceeded. This functional behavior was consistent with a critical state model for the dynamic resistance, but discrepancies in absolute value of the dynamic resistance suggested that further theoretical development is needed.

  1. Near-field radiative heat transfer between metamaterials coated with silicon carbide thin films

    SciTech Connect

    Basu, Soumyadipta Yang, Yue; Wang, Liping

    2015-01-19

    In this letter, we study the near-field radiative heat transfer between two metamaterial substrates coated with silicon carbide (SiC) thin films. It is known that metamaterials can enhance the near-field heat transfer over ordinary materials due to excitation of magnetic plasmons associated with s polarization, while strong surface phonon polariton exists for SiC. By careful tuning of the optical properties of metamaterial, it is possible to excite electrical and magnetic resonances for the metamaterial and surface phonon polaritons for SiC at different spectral regions, resulting in the enhanced heat transfer. The effect of the SiC film thickness at different vacuum gaps is investigated. Results obtained from this study will be beneficial for application of thin film coatings for energy harvesting.

  2. Superior properties of SmBCO coated conductors at high magnetic fields and elevated temperatures

    NASA Astrophysics Data System (ADS)

    Fuger, R.; Eisterer, M.; Oh, S. S.; Weber, H. W.

    2010-03-01

    In addition to the well investigated YBa 2Cu 3O 7-δ (Y-123, YBCO) compound, many other rare earth-123 compounds are candidate materials for the production of coated conductors. Sm-123 seems to be an excellent alternative because of its higher transition temperature ( T c) and higher critical current densities ( J c) in external magnetic fields. Because of the fast decrease of J c in YBCO at elevated temperatures, especially around the boiling point of liquid nitrogen, the slightly higher T c can be an important advantage. Recently, significant progress has been made in the production of long length Sm-123 based coated conductors. We report here on transport measurements on these conductors in the liquid nitrogen temperature range. The critical current densities were determined as a function of the applied field and the crystallographic orientation under maximum Lorentz force configuration. A shift of the c-axis (∼7°) from the tape normal was found. The conductor properties were compared to those of commercially available YBCO coated conductors. The critical current densities as well as the irreversibility fields are higher in the SmBCO tapes, thus demonstrating the superior properties of the Sm-123 compound.

  3. Joint actions of environmental nonionizing electromagnetic fields and chemical pollution in cancer promotion.

    PubMed Central

    Adey, W R

    1990-01-01

    Studies of environmental electromagnetic (EM) field interactions in tissues have contributed to a new understanding of both normal growth and the biology of cancer in cell growth. From cancer research comes a floodtide of new knowledge about the disruption of communication by cancer-promoting chemicals with an onset of unregulated growth. Bioelectromagnetic research reveals clear evidence of joint actions at cell membranes of chemical cancer promoters and environmental electromagnetic fields. The union of these two disciplines has resulted in the first major new approach to tumor formation in 75 years, directing attention to dysfunctions in inward and outward streams of signals at cell membranes, rather than to damage DNA in cell nuclei, and to synergic actions of chemical pollutants and environmental electromagnetic fields. We are witnesses and, in great measure, participants in one of the great revolutions in the history of biology. In little more than a century, we have moved from organs, to tissues, to cells, and finally to the molecules that are the elegant fabric of living tissues. Today, we stand at a new frontier. It may be more difficult to comprehend, but it is far more significant; for it is at the atomic level, rather than the molecular, that physical, rather than chemical, processes appear to shape the flow of signals that are at the essence of living matter. To pursue these problems in the environment and in the laboratory, our needs for further research with appropriate budgets are great.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2205491

  4. Joint inference of groundwater-recharge and hydraulic-conductivity fields from head data using the ensemble Kalman filter

    NASA Astrophysics Data System (ADS)

    Erdal, D.; Cirpka, O. A.

    2016-02-01

    Regional groundwater flow strongly depends on groundwater recharge and hydraulic conductivity. Both are spatially variable fields, and their estimation is an ongoing topic in groundwater research and practice. In this study, we use the ensemble Kalman filter as an inversion method to jointly estimate spatially variable recharge and conductivity fields from head observations. The success of the approach strongly depends on the assumed prior knowledge. If the structural assumptions underlying the initial ensemble of the parameter fields are correct, both estimated fields resemble the true ones. However, erroneous prior knowledge may not be corrected by the head data. In the worst case, the estimated recharge field resembles the true conductivity field, resulting in a model that meets the observations but has very poor predictive power. The study exemplifies the importance of prior knowledge in the joint estimation of parameters from ambiguous measurements.

  5. Optical coatings and thin films for display technologies using closed-field magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Gibson, Desmond R.; Brinkley, Ian; Walls, J. M.

    2004-11-01

    "Closed field" magnetron (CFM) sputtering offers high throughput, flexible deposition process for optical coatings and thin films required in display technologies. CFM sputtering uses two or more different metal targets to deposit multilayers comprising a wide range of dielectrics, metals and conductive oxides. CFM provides a room temperature deposition process with high ion current density, low bias voltage and reactive oxidation in the entire volume around the rotating substrate drum carrier, depositing films over a large surface area at a high rate with excellent and reproducible properties. Machines based on CFM are scaleable to meet a range of batch and in-line size requirements. Thin film thickness control to <+/-1% is accomplished using time, although quartz crystal or optical monitoring are used for more demanding applications. Fine layer thickness control and deposition of graded index layers is also assisted with a special rotating shutter mechanism. This paper presents data on optical properties for CFM deposited coatings relevant to displays, including anti-reflection, IR blocker and color and thermal control filters, graded coatings, barrier coatings as well as conductive transparent oxides such as indium tin oxide. Benefits of the CFM process for a range of display technologies; OLED, EL and projection are described.

  6. 3D stochastic inversion and joint inversion of potential fields for multi scale parameters

    NASA Astrophysics Data System (ADS)

    Shamsipour, Pejman

    In this thesis we present the development of new techniques for the interpretation of potential field (gravity and magnetic data), which are the most widespread economic geophysical methods used for oil and mineral exploration. These new techniques help to address the long-standing issue with the interpretation of potential fields, namely the intrinsic non-uniqueness inversion of these types of data. The thesis takes the form of three papers (four including Appendix), which have been published, or soon to be published, in respected international journals. The purpose of the thesis is to introduce new methods based on 3D stochastical approaches for: 1) Inversion of potential field data (magnetic), 2) Multiscale Inversion using surface and borehole data and 3) Joint inversion of geophysical potential field data. We first present a stochastic inversion method based on a geostatistical approach to recover 3D susceptibility models from magnetic data. The aim of applying geostatistics is to provide quantitative descriptions of natural variables distributed in space or in time and space. We evaluate the uncertainty on the parameter model by using geostatistical unconditional simulations. The realizations are post-conditioned by cokriging to observation data. In order to avoid the natural tendency of the estimated structure to lay near the surface, depth weighting is included in the cokriging system. Then, we introduce algorithm for multiscale inversion, the presented algorithm has the capability of inverting data on multiple supports. The method involves four main steps: i. upscaling of borehole parameters (It could be density or susceptibility) to block parameters, ii. selection of block to use as constraints based on a threshold on kriging variance, iii. inversion of observation data with selected block densities as constraints, and iv. downscaling of inverted parameters to small prisms. Two modes of application are presented: estimation and simulation. Finally, a novel

  7. Structural characterization of electric-field assisted dip-coating of gold nanoparticles on silicon

    NASA Astrophysics Data System (ADS)

    Dushaq, Ghada H.; Alkhatib, Amro; Rasras, Mahmoud S.; Nayfeh, Ammar M.

    2015-09-01

    We report the effect of applying an electric field on the surface coverage of 40nm gold colloidal nanoparticles on silicon wafer using dip-coating and electrochemical cell set up. By applying electric field during the dip-coating of silicon wafer in a solution of gold nano particles (GNP) the surface coverage increased by 10% when the electric field varied from 5V/cm to 25V/cm at fixed deposition time of 90s. Ultra High Resolution Scanning Electron Microscopy (HRSEM) images shows that the particle agglomeration becomes more noticeable at higher electric field and as the deposition time increases from 90 s to 20 min a thin film of gold is achieved. Moreover, the results are discussed in terms of chemical bonding, electrostatic force and electrophoretic mobility of Au nano particles during the electric field enhanced deposition on the Si surface. Applied voltage, time of dipping, concentration of the aqueous solution, and particles zeta potential are all can be controlled to enhance the uniformity and particles profile on the silicon surface.

  8. Structural characterization of electric-field assisted dip-coating of gold nanoparticles on silicon

    SciTech Connect

    Dushaq, Ghada H.; Alkhatib, Amro; Rasras, Mahmoud S.; Nayfeh, Ammar M.

    2015-09-15

    We report the effect of applying an electric field on the surface coverage of 40nm gold colloidal nanoparticles on silicon wafer using dip-coating and electrochemical cell set up. By applying electric field during the dip-coating of silicon wafer in a solution of gold nano particles (GNP) the surface coverage increased by 10% when the electric field varied from 5V/cm to 25V/cm at fixed deposition time of 90s. Ultra High Resolution Scanning Electron Microscopy (HRSEM) images shows that the particle agglomeration becomes more noticeable at higher electric field and as the deposition time increases from 90 s to 20 min a thin film of gold is achieved. Moreover, the results are discussed in terms of chemical bonding, electrostatic force and electrophoretic mobility of Au nano particles during the electric field enhanced deposition on the Si surface. Applied voltage, time of dipping, concentration of the aqueous solution, and particles zeta potential are all can be controlled to enhance the uniformity and particles profile on the silicon surface.

  9. On the potential for fibronectin/phosphorylcholine coatings on PTFE substrates to jointly modulate endothelial cell adhesion and hemocompatibility properties

    PubMed Central

    Montaño-Machado, Vanessa; Chevallier, Pascale; Mantovani, Diego; Pauthe, Emmanuel

    2015-01-01

    The use of biomolecules as coatings on biomaterials is recognized to constitute a promising approach to modulate the biological response of the host. In this work, we propose a coating composed by 2 biomolecules susceptible to provide complementary properties for cardiovascular applications: fibronectin (FN) to enhance endothelialization, and phosphorylcholine (PRC) for its non thrombogenic properties. Polytetrafluoroethylene (PTFE) was selected as model substrate mainly because it is largely used in cardiovascular applications. Two approaches were investigated: 1) a sequential adsorption of the 2 biomolecules and 2) an adsorption of the protein followed by the grafting of phosphorylcholine via chemical activation. All coatings were characterized by immunofluorescence staining, X-Ray Photoelectron Spectroscopy and Scanning Electron Microscopy analyses. Assays with endothelial cells showed improvement on cell adhesion, spreading and metabolic activity on FN-PRC coatings compared with the uncoated PTFE. Platelets adhesion and activation were both reduced on the coated surfaces when compared with uncoated PTFE. Moreover, clotting time tests exhibited better hemocompatibility properties of the surfaces after a sequential adsorption of FN and PRC. In conclusion, FN-PRC coating improves cell adhesion and non-thrombogenic properties, thus revealing a certain potential for the development of this combined deposition strategy in cardiovascular applications. PMID:25785369

  10. Inhibition of pyrite oxidation by surface coating agents: Batch and field studies

    NASA Astrophysics Data System (ADS)

    Choi, Jaeyoung; Do Gee, Eun; Yun, Hyun-Shik; Ram Lee, Woo; Park, Young-Tae

    2013-04-01

    The potential of several surface coating agents to inhibit the oxidation of metal sulfide minerals from Young-Dong coal mine and the Il-Gwang gold mine was examined by conducting laboratory scale batch experiments and field tests. Powdered pyrite as a standard sulfide mineral and rock samples from two mine outcrops were mixed with six coating agents (KH2PO4, MgO and KMnO4 as chemical agents, and apatite, cement and manganite as mineral agents) and incubated with oxidizing agents (H2O2 or NaClO). For the observed time period (8 days), Young-Dong coal mine samples exhibited the least sulfate (SO42-) production in the presence of KMnO4 (16%) or cement (4%) while, for Il-Gwang mine samples, the least SO42- production was observed in presence of KH2PO4 (8%) or cement (2%) compared to control. Field-scale pilot tests at the Il-Gwang site also showed that addition of KH2PO4 decreased SO42- production from 200 to 13 mg L-1 and it also reduced Cu and Mn from 8 and 3 mg L-1, respectively to <0.05 mg L-1 (below ICP-OES detection limits). The experimental results suggested that the use of surface coating agents is a promising alternative for sulfide oxidation inhibition at acid mine drainage sites.

  11. Inhibition of sulfide mineral oxidation by surface coating agents: batch and field studies.

    PubMed

    Ji, Min-Kyu; Gee, Eun-Do; Yun, Hyun-Shik; Lee, Woo-Ram; Park, Young-Tae; Khan, Moonis Ali; Jeon, Byong-Hun; Choi, Jaeyoung

    2012-08-30

    The potential of several surface coating agents to inhibit the oxidation of metal sulfide minerals from Young-Dong coal mine and the Il-Gwang gold mine was examined by conducting laboratory scale batch experiments and field tests. Powdered pyrite as a standard sulfide mineral and rock samples from two mine outcrops were mixed with six coating agents (KH(2)PO(4), MgO and KMnO(4) as chemical agents, and apatite, cement and manganite as mineral agents) and incubated with oxidizing agents (H(2)O(2) or NaClO). For the observed time period (8 days), Young-Dong coal mine samples exhibited the least sulfate (SO(4)(2-)) production in the presence of KMnO(4) (16%) or cement (4%) while, for Il-Gwang mine samples, the least SO(4)(2-) production was observed in presence of KH(2)PO(4) (8%) or cement (2%) compared to control. Field-scale pilot tests at the Il-Gwang site also showed that addition of KH(2)PO(4) decreased SO(4)(2-) production from 200 to 13 mg L(-1) and it also reduced Cu and Mn from 8 and 3 mg L(-1), respectively to <0.05 mg L(-1) (below ICP-OES detection limits). The experimental results suggested that the use of surface coating agents is a promising alternative for sulfide oxidation inhibition at acid mine drainage sites. PMID:22727481

  12. Influence of magnetization on field quality in cosine-theta and block design dipole magnets wound with coated conductors

    NASA Astrophysics Data System (ADS)

    Sogabe, Yusuke; Sakashita, Masaki; Nakamura, Taketsune; Ogitsu, Toru; Amemiya, Naoyuki

    2016-04-01

    We carried out electromagnetic field analyses on the cross sections of two dipole magnets wound with coated conductors. One was a cosine-theta magnet, and the other was a block design magnet. The electric field-current density characteristics of the coated conductors were formulated using a percolation depinning model based on the measured voltage-current characteristics. We calculated the temporal evolutions of the current-density distributions in all the turns of each magnet and used these evolutions to calculate the multipole components of the magnetic field. We compared the two magnets, which differed in coated-conductor orientations, regarding the influence of coated-conductor magnetization on the field qualities.

  13. Uniform trapped fields produced by stacks of HTS coated conductor tape

    NASA Astrophysics Data System (ADS)

    Mitchell-Williams, T. B.; Baskys, A.; Hopkins, S. C.; Kalitka, V.; Molodyk, A.; Glowacki, B. A.; Patel, A.

    2016-08-01

    The trapped magnetic field profile of stacks of GdBa2Cu3O7‑x superconducting tape was investigated. Angled stacks of superconducting tape were magnetized and found to produce very uniform trapped field profiles. The angled stacks were made of 12 mm × 24 mm solder coated tape pieces and were bonded together following a brief consolidation heat treatment. Layering multiple stacks together and adding a ferromagnetic plate beneath the samples were both found to enhance the magnitude and uniformity of the trapped field profiles. Stationary and time-dependent critical state finite element models were also developed to complement the experimental results and investigate the magnetization process. The size and shapes possible with the angled stacks make them attractive for applications requiring uniform magnetic fields over larger areas than can be achieved with existing bulk rings or tape annuli.

  14. Development of superlattice CrN/NbN coatings for joint replacements deposited by high power impulse magnetron sputtering.

    PubMed

    Hovsepian, Papken Ehiasarian; Ehiasarian, Arutiun Papken; Purandare, Yashodhan; Sugumaran, Arunprabhu Arunachalam; Marriott, Tim; Khan, Imran

    2016-09-01

    The demand for reliable coating on medical implants is ever growing. In this research, enhanced performance of medical implants was achieved by a CrN/NbN coating, utilising nanoscale multilayer/superlattice structure. The advantages of the novel high power impulse magnetron sputtering technology, namely, its unique highly ionised plasma, were exploited to deposit dense and strongly adherent coatings on CoCr implants. Transmission electron microscopy analysis revealed coating superlattice structure with bi-layer thickness of 3.5 nm. CrN/NbN deposited on CoCr samples showed exceptionally high adhesion, critical load values of LC2 = 50 N in scratch adhesion tests. Nanoindentation tests showed high hardness of 34 GPa and Young's modulus of 447 GPa. Low coefficient of friction (μ) 0.49 and coating wear coefficient (K C) = 4.94 × 10(-16) m(3) N(-1) m(-1) were recorded in dry sliding tests. Metal ion release studies showed a reduction in Co, Cr and Mo release at physiological and elevated temperatures (70 °C) to almost undetectable levels (<1 ppb). Rotating beam fatigue testing showed a significant increase in fatigue strength from 349 ± 59 MPa (uncoated) to 539 ± 59 MPa (coated). In vitro biological testing has been performed in order to assess the safety of the coating in biological environment; cytotoxicity, genotoxicity and sensitisation testing have been performed, all showing no adverse effects. PMID:27571960

  15. Enhanced Field Emission from Vertically Oriented Graphene by Thin Solid Film Coatings

    NASA Astrophysics Data System (ADS)

    Bagge-Hansen, Michael

    Recent progress and a coordinated national research program have brought considerable effort to bear on the synthesis and application of carbon nanostructures for field emission. At the College of William and Mary, we have developed field emission arrays of vertically oriented graphene (carbon nanosheets, CNS) that have demonstrated promising cathode performance, delivering emission current densities up to 2 mA/mm2 and cathode lifetime >800 hours. The work function (φ) of CNS and other carbonaceous cathode materials has been reported to be φ˜4.5-5.1 eV. The application of low work function thin films can achieve several orders of magnitude enhancement of field emission. Initially, the intrinsic CNS field emission was studied. The mean height of the CNS was observed to decrease as a function of operating time at a rate of ˜0.05 nm/h (I 1˜40 muA/mm2). The erosion mechanism was studied using a unique UHV diode design which allowed line-of-site assessment from the field emission region in the diode to the ion source of a mass spectrometer. The erosion of CNS was found to occur by impingement of hyperthermal H and O neutrals and ions generated at the surface oxide complex of the Cu anode by electron stimulated desorption. Techniques for minimizing this erosion are presented. The Mo2C (φ˜3.7 eV) beading on CNS at previously reported carbide formation temperatures of ˜800°C was circumvented by physical vapor deposition of Mo and vacuum annealing at ˜300°C which resulted in a conformal Mo2C coating and stable field emission of 1˜50 muA/mm2. For a given applied field, the emission current was >102 greater than uncoated CNS. ThO2 thin film coatings were presumed to be even more promising because of a reported work function of φ ˜2.6 eV. The fundamental behavior of the initial oxidation of polycrystalline Th was studied in UHV (p<1x10-11 Torr), followed by studies of thin film coatings on Ir and thermionic emission characteristics. Although a work function of 3

  16. Outstanding field emission properties of wet-processed titanium dioxide coated carbon nanotube based field emission devices

    SciTech Connect

    Xu, Jinzhuo; Ou-Yang, Wei Chen, Xiaohong; Guo, Pingsheng; Piao, Xianqing; Sun, Zhuo; Xu, Peng; Wang, Miao; Li, Jun

    2015-02-16

    Field emission devices using a wet-processed composite cathode of carbon nanotube films coated with titanium dioxide exhibit outstanding field emission characteristics, including ultralow turn on field of 0.383 V μm{sup −1} and threshold field of 0.657 V μm{sup −1} corresponding with a very high field enhancement factor of 20 000, exceptional current stability, and excellent emission uniformity. The improved field emission properties are attributed to the enhanced edge effect simultaneously with the reduced screening effect, and the lowered work function of the composite cathode. In addition, the highly stable electron emission is found due to the presence of titanium dioxide nanoparticles on the carbon nanotubes, which prohibits the cathode from the influence of ions and free radical created in the emission process as well as residual oxygen gas in the device. The high-performance solution-processed composite cathode demonstrates great potential application in vacuum electronic devices.

  17. Magnetorheological fluid based on submicrometric silica-coated magnetite particles under an oscillatory magnetic field

    NASA Astrophysics Data System (ADS)

    Agustín-Serrano, R.; Donado, F.; Rubio-Rosas, E.

    2013-06-01

    An experimental study conducted on the rheological properties of a magnetorheological fluid based on submicrometric silica-coated magnetite particles dispersed in silicone oil is presented. We investigated the rheological behaviour when the system is simultaneously exposed to a static field and a sinusoidal field used as a perturbation. The results show that the perturbation modifies the rheological behaviour of the system and can be used to control its physical properties; however, the changes that are induced are smaller than expected from previous results for the aggregation of particles under magnetic perturbations. We discussed this difference in terms of the ratio between the magnetic energy and the thermal energy. We observed that a threshold magnetic field exists; below it, the yield stress is practically zero, whereas above it, the yield stress grows quickly. We discuss this result in terms of a model based on chain length distribution.

  18. Physical insight toward electric field enhancement at nodular defects in optical coatings.

    PubMed

    Cheng, Xinbin; Tuniyazi, Abudusalamu; Wei, Zeyong; Zhang, Jinlong; Ding, Tao; Jiao, Hongfei; Ma, Bin; Li, Hongqiang; Li, Tongbao; Wang, Zhanshan

    2015-04-01

    Although the finite-difference time-domain (FDTD) technique has been prevailingly used to calculate the electric field intensity (EFI) enhancement at nodular defects in high-reflection (HR) coatings, the physical insight as to how the nodular features contribute to the intensified EFI is not explicitly revealed yet, which in turn limits the solutions that improve the laser-induced damage threshold (LIDT) of nodules by decreasing the EFI enhancement. Here, a simplified model is proposed to describe the intensified EFI in nodules: 1) the nodule works as a microlens and its focal length can be predicted using a simple formula, 2) the portion of incident light that penetrates through the HR coating can be estimated by knowing the angular dependent transmittance (ADT) of the nodule, 3) strong EFI enhancement is created when the focal point is within the nodule and simultaneously a certain portion of light penetrates to the focal position. In the light of the proposed model, a broadband HR coating was used to reduce the EFI enhancement at the seed by a factor about 10, which leads to a 20 times increment of the LIDT. This work therefore not only deepens the physical understanding of EFI enhancement at nodules but also provides a new way to increase the LIDT of multilayer reflective optics. PMID:25968699

  19. In-situ arsenic remediation by aquifer iron coating: Field trial in the Datong basin, China.

    PubMed

    Xie, Xianjun; Pi, Kunfu; Liu, Yaqing; Liu, Chongxuan; Li, Junxia; Zhu, Yapeng; Su, Chunli; Ma, Teng; Wang, Yanxin

    2016-01-25

    An aquifer Fe-coating technology was evaluated for in-situ As remediation. The groundwater in the aimed aquifer has low dissolved Fe(II) concentration and high As(III) concentration, which has a low affinity toward Fe-oxides/hydroxides. To overcome these challenges, dissolved Fe(II) (5.0 mM) and NaClO (2.6 mM) were injected into the studied aquifer to promote the formation of Fe oxides/hydroxides and to oxidize As(III) into As(V), thus removing aqueous As via adsorption and/or co-precipitation. During field experiment, As concentration in groundwater from the pumping well significantly decreased. Fe and As speciation calculations indicate that incorporation of negatively charged As(V) into goethite was the probable mechanism for As removal. Both chemical sequential extraction results and spectroscopic data also support that alternating injection of Fe(II) and NaClO can achieve aquifer Fe coating and immobilize As via adsorption onto Fe oxides/hydroxides. Geochemical modelling further confirms that although competition for sorption sites between As and other dissolved species is expected in the natural groundwater system, high surface area of the Fe oxides/hydroxides can provide sufficient sites for As retention. The ability to effectively decrease As concentration of in-situ aquifer Fe-coating technology indicates that this approach should have extensive applicability to similar high As groundwater occurred worldwide. PMID:26448490

  20. Microbe repelling coated stainless steel analysed by field emission scanning electron microscopy and physicochemical methods.

    PubMed

    Raulio, Mari; Järn, Mikael; Ahola, Juhana; Peltonen, Jouko; Rosenholm, Jarl B; Tervakangas, Sanna; Kolehmainen, Jukka; Ruokolainen, Timo; Narko, Pekka; Salkinoja-Salonen, Mirja

    2008-07-01

    Coating of stainless steel with diamond-like carbon or certain fluoropolymers reduced or almost eliminated adhesion and biofilm growth of Staphylococcus epidermidis, Deinococcus geothermalis, Meiothermus silvanus and Pseudoxanthomonas taiwanensis. These species are known to be pertinent biofilm formers on medical implants or in the wet-end of paper machines. Field emission scanning electron microscopic analysis showed that Staph. epidermidis, D. geothermalis and M. silvanus grew on stainless steel using thread-like organelles for adhesion and biofilm formation. The adhesion threads were fewer in number on fluoropolymer-coated steel than on plain steel and absent when the same strains were grown in liquid culture. Psx. taiwanensis adhered to the same surfaces by a mechanism involving cell ghosts on which the biofilm of live cells grew. Hydrophilic (diamond-like carbon) or hydrophobic (fluoropolymer) coatings reduced the adherence of the four test bacteria on different steels. Selected topographic parameters, including root-mean-square roughness (S (q)), skewness (S (sk)) and surface kurtosis (S (ku)), were analysed by atomic force microscopy. The surfaces that best repelled microbial adhesion of the tested bacteria had higher skewness values than those only slightly repelling. Water contact angle, measured (theta (m)) or roughness corrected (theta (y)), affected the tendency for biofilm growth in a different manner for the four test bacteria. PMID:18379832

  1. Quantitative assessments of residual stress fields at the surface of alumina hip joints.

    PubMed

    Pezzotti, Giuseppe; Munisso, Maria Chiara; Lessnau, Kristina; Zhu, Wenliang

    2010-11-01

    In-depth and in-plane response functions of photo- and electro-stimulated probes have been modeled and quantitatively evaluated in order to assess their suitability to detect the highly graded residual stress fields generated at the surface of alumina hip joints. Optical calibrations revealed large differences in probe size, which strongly affected the detected magnitude of residual stress. A comparison between the responses of Raman and fluorescence probes in polycrystalline alumina showed that the depth of those probes spread to an extent in the order of the tens of microns even with using a confocal probe configuration. On the other hand, the electro-stimulated luminescence emitted by oxygen vacancy sites (F(+) center) in the alumina lattice represented the most suitable choice for confining to a shallow volume the stress probe. This latter probe enabled us to reduce the measurement depth to the order of the tens of nanometers. We show maps of surface residual stress as collected on both main-wear and nonwear zones of an alumina femoral head. A comparison among stress maps taken at exactly the same location, but employing different probes, revealed averaging effects on the stress magnitude detected with photo-stimulated probes, while proving the superior spatial resolution of the electron probe. PMID:20848660

  2. Jointed goatgrass (Aegilops cylindrica) by imidazolinone-resistant wheat hybridization under field conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Gene flow between jointed goatgrass and winter wheat is a concern because transfer of herbicide resistance genes from imidazolinone-resistant (IR) winter wheat cultivars to jointed goatgrass could restrict weed management options for this serious weed of winter wheat cropping systems. The objective...

  3. Field and temperature scaling of the critical current density in commercial REBCO coated conductors

    NASA Astrophysics Data System (ADS)

    Senatore, Carmine; Barth, Christian; Bonura, Marco; Kulich, Miloslav; Mondonico, Giorgio

    2016-01-01

    Scaling relations describing the electromagnetic behaviour of coated conductors (CCs) greatly simplify the design of REBCO-based devices. The performance of REBCO CCs is strongly influenced by fabrication route, conductor architecture and materials, and these parameters vary from one manufacturer another. In the present work we have examined the critical surface for the current density, J c(T, B, θ), of coated conductors from six different manufacturers: American Superconductor Co. (US), Bruker HTS GmbH (Germany), Fujikura Ltd (Japan), SuNAM Co. Ltd (Korea), SuperOx ZAO (Russia) and SuperPower Inc. (US). Electrical transport and magnetic measurements were performed at temperatures between 4.2 K and 77 K and in magnetic fields of up to 19 T. Experiments were conducted at three different orientations of the field with respect to the crystallographic c-axis of the REBCO layer, θ = 0°, 45° and 90°, in order to probe the angular anisotropy of J c. In spite of the large variability of the CCs’ performance, we show here that field and temperature dependences of J c at a given angle can be reproduced over wide ranges using a scaling relation based only on three parameters. Furthermore, we present and validate a new approach combining magnetic and transport measurements for the determination of the scaling parameters with minimal experimental effort.

  4. Very Stable Electron Field Emission From Strontium Titanate Coated Carbon Nanotube Matrices With Low Emission Thresholds

    SciTech Connect

    Pandey, Archana; Prasad, Abhishek; Moscatello, Jason; Engelhard, Mark H.; Wang, Chong M.; Yap, Yoke K.

    2013-01-22

    PMMA-STO-CNT matrices were created by opened-tip vertically-aligned multiwalled carbon nanotubes (VA-MWCNTs) with conformal coating of strontium titanate and Poly(methyl methacrylate). Emission threshold of 0.8 V/μm was demonstrated, about five-fold lower than that of the as-grown VAMWCNTs. Theoretical simulation and modeling suggest that PMMA-STO-CNT matrices have suppressed screening effects and Coulombs’ repulsion forces between electrons in adjacent CNTs, leading to low emission threshold, high emission density, and prolong emission stability. These findings are important for practical application of VA-MWCNTs in field emission devices.

  5. Insert Coil Test for HEP High Field Magnets Using YBCO Coated Conductor Tapes

    SciTech Connect

    Lombardo, V.; Barzi, E.; Turrioni, D.; Zlobin, A.V.; /Fermilab

    2011-06-15

    The final beam cooling stages of a Muon Collider may require DC solenoid magnets with magnetic fields of 30-50 T. In this paper we present progress in insert coil development using commercially available YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} Coated Conductor. Technological aspects covered in the development, including coil geometry, insulation, manufacturing process and testing are summarized and discussed. Test results of double pancake coils operated in liquid nitrogen and liquid helium are presented and compared with the performance of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} tape short samples.

  6. Transparent Conductive Coating Based on Carbon Nanotubes Using Electric Field Deposition Method

    SciTech Connect

    Latununuwe, Altje; Hattu, Nikmans; Setiawan, Andhy; Winata, Toto; Abdullah, Mikrajuddin; Darma, Yudi

    2010-10-24

    The transparent conductive coating based on carbon nanotubes (CNTs) had been fabricated using the electric field deposition method. The scanning electron microscope (SEM) results show a quite uniform CNTs on Corning glass substrates. Moreover the X-ray Diffraction (XRD) results shows the peak at around 25 deg. which proves the existence of CNT materials. The CNT thin films obtained with different deposition times have different transmittance coefficients at wavelength of 550 nm. I-V measurement results shows higher sheet resistance value which relates with bigger transmittance coefficients and vice versa.

  7. 21 CFR 888.3358 - Hip joint metal/polymer/metal semi-constrained porous-coated uncemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... titanium-aluminum-vanadium (Ti-6Al-4V) alloy and an acetabular component composed of an ultra-high... titanium or Ti-6Al-4V alloy. The porous coating has a volume porosity between 30 and 70 percent, an...

  8. 21 CFR 888.3358 - Hip joint metal/polymer/metal semi-constrained porous-coated uncemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... titanium-aluminum-vanadium (Ti-6Al-4V) alloy and an acetabular component composed of an ultra-high... titanium or Ti-6Al-4V alloy. The porous coating has a volume porosity between 30 and 70 percent, an...

  9. 21 CFR 888.3358 - Hip joint metal/polymer/metal semi-constrained porous-coated uncemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... titanium-aluminum-vanadium (Ti-6Al-4V) alloy and an acetabular component composed of an ultra-high... titanium or Ti-6Al-4V alloy. The porous coating has a volume porosity between 30 and 70 percent, an...

  10. Conjugate (solid/fluid) computational fluid dynamics analysis of the space shuttle solid rocket motor nozzle/case and case field joints

    NASA Technical Reports Server (NTRS)

    Doran, D.; Keeton, L. W.; Dionne, P. J.; Singhal, A. K.

    1989-01-01

    Three-dimensional, conjugate (solid/fluid) heat transfer analyses of new designs of the Solid Rocket Motor (SRM) nozzle/case and case field joints are described. The main focus was to predict the consequences of multiple rips (or debonds) in the ambient cure adhesive packed between the nozzle/case joint surfaces and the bond line between the mating field joint surfaces. The models calculate the transient temperature responses of the various materials neighboring postulated flow/leakpaths into, past, and out from the nozzle/case primary O-ring cavity and case field capture O-ring cavity. These results were used to assess if the design was failsafe (i.e., no potential O-ring erosion) and reusable (i.e., no excessive steel temperatures). The models are adaptions and extensions of the general purpose PHOENICS fluid dynamics code. A non-orthogonal coordinate system was employed and 11,592 control cells for the nozzle/case and 20,088 for the case field joints are used with non-uniform distribution. Physical properties of both fluid and solids are temperature dependent. A number of parametric studies were run for both joints with results showing temperature limits for reuse for the steel case on the nozzle joint being exceeded while the steel case temperatures for the field joint were not. O-ring temperatures for the nozzle joint predicted erosion while for the field joint they did not.

  11. A comparative study of spin coated and floating film transfer method coated poly (3-hexylthiophene)/poly (3-hexylthiophene)-nanofibers based field effect transistors

    NASA Astrophysics Data System (ADS)

    Tiwari, Shashi; Takashima, Wataru; Nagamatsu, S.; Balasubramanian, S. K.; Prakash, Rajiv

    2014-09-01

    A comparative study on electrical performance, optical properties, and surface morphology of poly(3-hexylthiophene) (P3HT) and P3HT-nanofibers based "normally on" type p-channel field effect transistors (FETs), fabricated by two different coating techniques has been reported here. Nanofibers are prepared in the laboratory with the approach of self-assembly of P3HT molecules into nanofibers in an appropriate solvent. P3HT (0.3 wt. %) and P3HT-nanofibers (˜0.25 wt. %) are used as semiconductor transport materials for deposition over FETs channel through spin coating as well as through our recently developed floating film transfer method (FTM). FETs fabricated using FTM show superior performance compared to spin coated devices; however, the mobility of FTM films based FETs is comparable to the mobility of spin coated one. The devices based on P3HT-nanofibers (using both the techniques) show much better performance in comparison to P3HT FETs. The best performance among all the fabricated organic field effect transistors are observed for FTM coated P3HT-nanofibers FETs. This improved performance of nanofiber-FETs is due to ordering of fibers and also due to the fact that fibers offer excellent charge transport facility because of point to point transmission. The optical properties and structural morphologies (P3HT and P3HT-nanofibers) are studied using UV-visible absorption spectrophotometer and atomic force microscopy , respectively. Coating techniques and effect of fiber formation for organic conductors give information for fabrication of organic devices with improved performance.

  12. A comparative study of spin coated and floating film transfer method coated poly (3-hexylthiophene)/poly (3-hexylthiophene)-nanofibers based field effect transistors

    SciTech Connect

    Tiwari, Shashi; Balasubramanian, S. K.; Takashima, Wataru; Nagamatsu, S.; Prakash, Rajiv

    2014-09-07

    A comparative study on electrical performance, optical properties, and surface morphology of poly(3-hexylthiophene) (P3HT) and P3HT-nanofibers based “normally on” type p-channel field effect transistors (FETs), fabricated by two different coating techniques has been reported here. Nanofibers are prepared in the laboratory with the approach of self-assembly of P3HT molecules into nanofibers in an appropriate solvent. P3HT (0.3 wt. %) and P3HT-nanofibers (∼0.25 wt. %) are used as semiconductor transport materials for deposition over FETs channel through spin coating as well as through our recently developed floating film transfer method (FTM). FETs fabricated using FTM show superior performance compared to spin coated devices; however, the mobility of FTM films based FETs is comparable to the mobility of spin coated one. The devices based on P3HT-nanofibers (using both the techniques) show much better performance in comparison to P3HT FETs. The best performance among all the fabricated organic field effect transistors are observed for FTM coated P3HT-nanofibers FETs. This improved performance of nanofiber-FETs is due to ordering of fibers and also due to the fact that fibers offer excellent charge transport facility because of point to point transmission. The optical properties and structural morphologies (P3HT and P3HT-nanofibers) are studied using UV-visible absorption spectrophotometer and atomic force microscopy , respectively. Coating techniques and effect of fiber formation for organic conductors give information for fabrication of organic devices with improved performance.

  13. Inhibition of pyrite oxidation by surface coating: a long-term field study.

    PubMed

    Kang, Chan-Ung; Jeon, Byong-Hun; Park, Seong-Sook; Kang, Jin-Soo; Kim, Kang-Ho; Kim, Dong-Kwan; Choi, Ui-Kyu; Kim, Sun-Joon

    2016-10-01

    Pyrite and other iron sulfides are readily oxidized by dissolved oxygen in aqueous phase, producing acidity and Fe(2+), which causes significant environmental problems. Applications of surface coating agents (Na2SiO3 and KH2PO4) were conducted at Boeun (Chungbuk, South Korea) outcrop site, and their efficiencies to inhibit the oxidation of sulfide minerals were monitored for a long-term period (449 days). The rock sample showed positive Net Acid Production Potential (NAPP = 20.23) and low Net Acid Generation pH (NAGpH = 2.42) values, suggesting that the rock sample was categorized in the potential acid-forming group. For the monitored time period (449 days), field study results showed that the application of Na2SiO3 effectively inhibited the pyrite oxidation as compared to KH2PO4. Na2SiO3 as a surface coating agent maintained pH 5-6 and reduced oxidation of pyrite surface up to 99.95 and 97.70 % indicated by Fe(2+) and SO4 (2-) release, respectively. The scanning electron microscope and energy-dispersive X-ray spectrometer analysis indicated that the morphology of rock surface was completely changed attributable to formation of iron silicate coating. The experimental results suggested that the treatment with Na2SiO3 was highly effective and it might be applicable on field for inhibition of iron sulfide oxidation. PMID:26493832

  14. Voltage-ampere characteristics of YBCO coated conductor under inhomogeneous oscillating magnetic field

    NASA Astrophysics Data System (ADS)

    Geng, J.; Shen, B.; Li, C.; Zhang, H.; Matsuda, K.; Li, J.; Zhang, X.; Coombs, T. A.

    2016-06-01

    Direct current carrying type II superconductors present a dynamic resistance when subjected to an oscillating magnetic field perpendicular to the current direction. If a superconductor is under a homogeneous field with high magnitude, the dynamic resistance value is nearly independent of transport current. Hoffmann and coworkers [Hoffmann et al., IEEE Trans. Appl. Supercond. 21, 1628 (2011)] discovered, however, flux pumping effect when a superconducting tape is under an inhomogeneous field orthogonal to the tape surface generated by rotating magnets. Following their work, we report the whole Voltage-Ampere (V-I) curves of an YBCO coated conductor under permanent magnets rotating with different frequencies and directions. We discovered that the two curves under opposite rotating directions differ from each other constantly when the transport current is less than the critical current, whereas the difference gradually reduces after the transport current exceeds the critical value. We also find that for different field frequencies, the difference between the two curves decreases faster with lower field frequency. The result indicates that the transport loss is dependent on the relative direction of the transport current and field travelling, which is distinct from traditional dynamic resistance model. The work may be instructive for the design of superconducting motors.

  15. Joints at high angles to normal fault strike: an explanation using 3-D numerical models of fault-perturbed stress fields

    NASA Astrophysics Data System (ADS)

    Kattenhorn, Simon A.; Aydin, Atilla; Pollard, David D.

    2000-01-01

    Structural methods based on homogeneous stress states predict that joints growing in an extending crust form with strike orientations identical to normal faults. However, we document a field example where the strikes of genetically related normal faults and joints are almost mutually perpendicular. Field relationships allowed us to constrain the fracture sequence and tectonic environment for fault and joint growth. We hypothesize that fault slip can perturb the surrounding stress field in a manner that controls the orientations of induced secondary structures. Numerical models were used to examine the stress field around normal faults, taking into consideration the effects of 3-D fault shape, geometrical arrangement of overlapping faults, and a range of stress states. The calculated perturbed stress fields around model normal faults indicate that it is possible for joints to form at high angles to fault strike. Such joint growth may occur at the lateral tips of an isolated fault, but is most likely in a relay zone between overlapping faults. However, the angle between joints and faults is also influenced by the remote stress state, and is particularly sensitive to the ratio of fault-parallel to fault-perpendicular stress. As this ratio increases, joints can propagate away from faults at increasingly higher angles to fault strike. We conclude that the combined remote stress state and perturbed local stress field associated with overlapping fault geometries resulted in joint growth at high angles to normal fault strike at a field location in Arches National Park, Utah.

  16. Deposition and field emission properties of highly crystallized silicon films on aluminum-coated polyethylene napthalate

    NASA Astrophysics Data System (ADS)

    Li, Junshuai; Wang, Jinxiao; Yin, Min; Gao, Pingqi; He, Deyan; Chen, Qiang; Shirai, Hajime

    2007-08-01

    Highly crystallized silicon films were deposited on aluminum-coated polyethylene napthalate (PEN) substrates by inductively coupled plasma (ICP-) chemical vapor deposition (CVD) at room temperature. The films with uniform grains about 50 nm have the (1 1 1) preferred orientation. By studying the relation of the silicon film crystallinity to the flow ratio of SiH 4 to H 2, it was found that the interaction between precursors and aluminum layers plays an important role in the crystallization process. The surface roughness of the resultant films was analyzed by atomic force microscopy (AFM). The results reveal that the roughness of the silicon films on aluminum-coated PEN substrates, compared to the films on bare PEN substrates, is dependent on the film phase rather than the substrate morphology. The measurement of field electron emission of the crystalline silicon film indicates that the threshold field is about 8.3 V/μm and the emission is reproducible in the emission region.

  17. Field Emission Lamps Prepared with Dip-Coated and Nickel Electroless Plated Carbon Nanotube Cathodes.

    PubMed

    Pu, N W; Youh, M J; Chung, K J; Liu, Y M; Ger, M D

    2015-07-01

    Fabrication and efficiency enhancement of tubal field emission lamps (FELs) using multi-walled carbon nanotubes (MWNTs) as the cathode field emitters were studied. The cathode filaments were prepared by eletrolessly plating a nickel (Ni) film on the cathode made of a 304 stainless steel wire dip-coated with MWNTs. The 304 wire was dip-coated with MWNTs and nano-sized Pd catalyst in a solution, and then eletrolessly plated with Ni to form an MWNT-embedded composite film. The MWNTs embedded in Ni not only had better adhesion but also exhibited a higher FE threshold voltage, which is beneficial to our FEL system and can increase the luminous efficiency of the anode phosphor. Our results show that the FE cathode prepared by dipping three times in a solution containing 400 ppm Pd nano-catalysts and 0.2 wt.% MWNTs and then eletrolessly plating a Ni film at a deposition temperature of 60 °C, pH value of 5, and deposition time of 7 min has the best FE uniformity and efficiency. Its emission current can stay as low as 2.5 mA at a high applied voltage of 7 kV, which conforms to the high-voltage-and-low-current requirement of the P22 phosphor and can therefore maximize the luminous efficiency of our FEL. We found that the MWNT cathodes prepared by this approach are suitable for making high-efficiency FELs. PMID:26373085

  18. Wear studies on plasma-sprayed Al2O3 and 8mole% of Yttrium-stabilized ZrO2 composite coating on biomedical Ti-6Al-4V alloy for orthopedic joint application

    PubMed Central

    Ganapathy, Perumal; Manivasagam, Geetha; Rajamanickam, Asokamani; Natarajan, Alagumurthi

    2015-01-01

    This paper presents the wear characteristics of the composite ceramic coating made with Al2O3-40wt%8YSZ on the biomedical grade Ti-6Al-4V alloy (grade 5) used for total joint prosthetic components, with the aim of improving their tribological behavior. The coatings were deposited using a plasma spraying technique, and optimization of plasma parameters was performed using response surface methodology to obtain dense coating. The tribological behaviors of the coated and uncoated substrates were evaluated using a ball-on-plate sliding wear tester at 37°C in simulated body-fluid conditions. The microstructure of both the titanium alloy and coated specimen were examined using an optical microscope and scanning electron microscope. The hardness of the plasma-sprayed alumina–zirconia composite coatings was 2.5 times higher than that of the Ti-6Al-4V alloy, while the wear rate of Ti-6Al-4V alloy was 253 times higher than that of the composite-coated Ti-6Al-4V alloy. The superior wear resistance of the alumina–zirconia coated alloy is attributed to its enhanced hardness and intersplat bonding strength. Wear-track examination showed that the predominant wear mechanism of Ti-6Al-4V alloy was abrasive and adhesive wear, whereas, in the case of alumina–zirconia composite coated alloy, the wear was dominated by microchipping and microcracking. PMID:26491323

  19. Flight Set 360L006 STS-34 field joint protection system, thermal protection system, and systems tunnel components, volume 4

    NASA Technical Reports Server (NTRS)

    Wilkinson, J. P.

    1990-01-01

    The performance of the thermal protection system, field joint protection system, and systems tunnel components of Flight Set 360L006, are documented, as evaluated by postflight hardware inspection. The condition of both motors was similar to previous flights. Sixteen aft edge hits were noted on the ground environment instrumentation thermal protection system. Each hit left a clean substrate, indicating that the damage was caused by nozzle severance debris and/or water impact. No National Space and Transporation System debris criteria for missing thermal protection system were violated. One 5.0 by 1.0 in. unbond was observed on the left hand center field joint K5NA closeout and was elevated to an in-flight anomaly (STS-34-M-4) by the NASA Ice/Debris team. Aft edge damage to the K5NA and an associated black streak indicate that burning debris from the nozzle severance system was the likely cause of the damage. Minor divots caused by debris were seen on previous flights, but this is the first occurrence of a K5NA unbond. Since the unbond occurred after booster separation there is no impact on flight safety and no corrective actions was taken. The right hand center field joint primary heater failed the dielectric withstanding voltage test after joint closeout. The heater was then disabled by opening the circuit breaker, and the redundant heater was used. The redundant heater performed nominally during the launch countdown. A similar condition occurred on Flight 4 when a secondary joint heater failed the dielectric withstanding voltage test.

  20. The 2000 revision of the joint UK/US geomagnetic field models and an IGRF 2000 candidate model

    USGS Publications Warehouse

    Macmillan, S.; Quinn, J.M.

    2000-01-01

    The method of derivation of the joint UK/US spherical harmonic geomagnetic main-field and secular-variation models is presented. Early versions of these models, with the main field truncated at degree 10, are the UK/US candidates for the IGRF 2000 model. The main-field model describes the Earth's magnetic field at the 2000.0 epoch, while the secular-variation model predicts the evolution of this field between 2000.0 and 2005.0. A revised 1995.0 main-field model was also generated. Regional models for the continental US, Alaska and Hawaii were also produced as a by-product of the UK/US global modelling effort. Copy right?? The Society of Geomagnetism and Earth, Planetary and Space Sciences (SGEPSS); The Seismological Society of Japan; The Volcanological Society of Japan; The Geodetic Society of Japan; The Japanese Society for Planetary Sciences.

  1. Pipeline joint protector

    SciTech Connect

    Baker, R.

    1989-02-28

    This patent describes a weight coated pipeline joint protective apparatus for protecting pipeline joints against impact or high stress concentrations. It consists of a high density plastic sheet wrapped around a pipeline joint with the opposite edges of such sheet overlaying the weight of coat material on the abutting pipes forming the joint. The first end of the sheet overlaps the wrapped sheet with means for securing such first end to the sheet surface near or adjacent to the opposite end of such sheet.

  2. Insights on formation mechanism of colorful silica coatings on Kilauean basalts from field observations and silicon isotopes

    NASA Astrophysics Data System (ADS)

    Chemtob, S. M.; Stebbins, J. F.; Guan, Y.; Ziegler, K. G.; Hurowitz, J. A.; Eiler, J. M.; Rossman, G. R.

    2011-12-01

    Many young basalts from Kilauea, on the big island of Hawai'i, feature visually striking white, yellow, orange and blue coatings. These coatings represent an opportunity to study the early onset of acid-sulfate weathering in volcanic environments. The coatings, first investigated on 1974 flows in the Ka'u Desert, consist of a 10-50 μm thick layer of amorphous silica, capped, in some cases, by a ~1 μm layer of Fe-Ti oxide. Both layers contain %-level enrichments of S, and jarosite is present as a minor phase. The coatings often display residual morphologies consistent with formation by leaching, but occasionally demonstrate depositional or accumulative morphology. Coated basalts of various ages (1969-2010) were collected from several sites along the SW and E rift zones of Kilauea to characterize variability in coating properties and the timing of coating formation. As early as one month after emplacement, some lava surfaces feature translucent, discontinuous 2-3 μm silica glazes, and lavas emplaced as recently as 2007 feature mature coating morphologies. Coatings tend to occur most prominently on smooth, low-vesicularity lavas, such as spatter and volcanic bombs. Rougher surfaces tend not to preserve coatings due to enhanced erosion. Older but recently exposed or broken surfaces away from active eruptions appear to regrow bright glazes with similar qualities, suggesting the importance of regional vog or acid rain in coating formation. Field observations illustrate the timing and complexity of silica coating growth, but do not address the coating formation mechanism and degree of Si mobility. Recent work, including in situ silicon isotope analysis via SIMS and detailed structural analysis via 29Si NMR and Raman spectroscopy, strongly suggests that the coatings are depositional and that Si was mobile during coating formation. 29Si NMR spectra indicate that the coating is structurally identical to amorphous silica gel and contains unusually high structural water

  3. Applied electric field enhances DRG neurite growth: influence of stimulation media, surface coating and growth supplements

    NASA Astrophysics Data System (ADS)

    Wood, Matthew D.; Willits, Rebecca Kuntz

    2009-08-01

    Electrical therapies have been found to aid repair of nerve injuries and have been shown to increase and direct neurite outgrowth during stimulation. This enhanced neural growth existed even after the electric field (EF) or stimulation was removed, but the factors that may influence the enhanced growth, such as stimulation media or surface coating, have not been fully investigated. This study characterized neurite outgrowth and branching under various conditions: EF magnitude and application time, ECM surface coating, medium during EF application and growth supplements. A uniform, low-magnitude EF (24 or 44 V m-1) was applied to dissociated chick embryo dorsal root ganglia seeded on collagen or laminin-coated surfaces. During the growth period, cells were either exposed to NGF or N2, and during stimulation cells were exposed to either unsupplemented media (Ca2+) or PBS (no Ca2+). Parallel controls for each experiment included cells exposed to the chamber with no stimulation and cells remaining outside the chamber. After brief electrical stimulation (10 min), neurite length significantly increased 24 h after application for all conditions studied. Of particular interest, increased stimulation time (10-100 min) further enhanced neurite length on laminin but not on collagen surfaces. Neurite branching was not affected by stimulation on any surface, and no preferential growth of neurites was noted after stimulation. Overall, the results of this report suggest that short-duration electric stimulation is sufficient to enhance neurite length under a variety of conditions. While further data are needed to fully elucidate a mechanism for this increased growth, these data suggest that one focus of those investigations should be the interaction between the growth cone and the substrata.

  4. Applied electric field enhances DRG neurite growth: influence of stimulation media, surface coating and growth supplements.

    PubMed

    Wood, Matthew D; Willits, Rebecca Kuntz

    2009-08-01

    Electrical therapies have been found to aid repair of nerve injuries and have been shown to increase and direct neurite outgrowth during stimulation. This enhanced neural growth existed even after the electric field (EF) or stimulation was removed, but the factors that may influence the enhanced growth, such as stimulation media or surface coating, have not been fully investigated. This study characterized neurite outgrowth and branching under various conditions: EF magnitude and application time, ECM surface coating, medium during EF application and growth supplements. A uniform, low-magnitude EF (24 or 44 V m(-1)) was applied to dissociated chick embryo dorsal root ganglia seeded on collagen or laminin-coated surfaces. During the growth period, cells were either exposed to NGF or N2, and during stimulation cells were exposed to either unsupplemented media (Ca(2+)) or PBS (no Ca(2+)). Parallel controls for each experiment included cells exposed to the chamber with no stimulation and cells remaining outside the chamber. After brief electrical stimulation (10 min), neurite length significantly increased 24 h after application for all conditions studied. Of particular interest, increased stimulation time (10-100 min) further enhanced neurite length on laminin but not on collagen surfaces. Neurite branching was not affected by stimulation on any surface, and no preferential growth of neurites was noted after stimulation. Overall, the results of this report suggest that short-duration electric stimulation is sufficient to enhance neurite length under a variety of conditions. While further data are needed to fully elucidate a mechanism for this increased growth, these data suggest that one focus of those investigations should be the interaction between the growth cone and the substrata. PMID:19494423

  5. East Meets West on "Double Star", a Joint Mission to Explore Earth's Magnetic Field

    NASA Astrophysics Data System (ADS)

    2001-07-01

    ESA Director General Antonio Rodotà and Luan Enjie, Administrator of the CNSA, signed an official agreement that will enable European experiments to be flown on Chinese satellites for the first time. "This agreement marks a significant advance for international cooperation in the exploration and peaceful use of outer space," said Mr. Rodotà. "It is one of the most important landmarks in scientific collaboration since ESA and the People's Republic of China first agreed to exchange scientific information more than 20 years ago." "The Double Star programme will be just the first step in substantial cooperation between the Chinese National Space Administration and ESA" said Mr Luan Enjie. "The signing of today's agreement paves the way not only for reciprocal cooperation between scientists, but for the establishment of comprehensive cooperation between the two agencies". Double Star will follow in the footsteps of ESA's groundbreaking Cluster mission by studying the effects of the Sun on the Earth's environment. Conducting joint studies with Cluster and Double Star should increase the overall scientific return from both missions. A key aspect of ESA's participation in the Double Star project is the inclusion of 10 instruments that are identical to those currently flying on the four Cluster spacecraft. A further eight experiments will be provided by Chinese institutes. "We hope it will be possible to make coordinated measurements with both Cluster and Double Star." said Cluster Project Scientist Philippe Escoubet. "For example, we would hope to carry out a joint exploration of the magnetotail, a region where storms of high energy particles are generated. When these particles reach Earth, they can cause power cuts, damage satellites and disrupt communications." Six of the eleven Cluster principal investigators have agreed to provide flight spares or duplicates of the experiments that are currently revolutionising our understanding of near-Earth space. This reuse of

  6. Semi-coupled flow and thermal analysis of the field joint during rapid pressurization of the redesigned solid rocket motor

    NASA Technical Reports Server (NTRS)

    Ghaffarian, Benny; Majumdar, Alok K.; Colbert, Robert; Clayton, J. L.

    1992-01-01

    A transient, semi-coupled, multi-dimensional thermal and flow analysis methodology was developed to predict the thermal/gas dynamic conditions in the field joint region of the Redesigned Solid Rocket Motor (RSRM). Transient temperature response, pressure history, and combustion gas flow rate (within the field joint region), were of principle interest, in the course of this study. The thermal environment in the field joint was modeled using SINDA, a finite difference based thermal network analyzer. The combustion gas flow boundary condition was generated using the FLAP code; this code performs a transient, lumped-parameter, control volume analysis to solve the mass, momentum, and energy conservation equations. The FLAP computer code was modified to account for erosion of the NBR insulation material, following ignition. An independent grid sensitivity study was conducted to determine an appropriate grid distribution near the wall. The predicted results, obtained using an optimum grid distribution and computer generated flow boundary condition, were compared with subscale test data.

  7. Stray magnetic field influence on the CPT resonance in a coated Rb vacuum cell

    NASA Astrophysics Data System (ADS)

    Taskova, E.; Alipieva, E.; Todorov, G.

    2016-03-01

    Interaction of a resonant laser beam with an atomic absorption medium creates population redistribution and interference between atomic levels. This anisotropy of the medium is experimentally observed as coherent population trapping (CPT) or electromagnetically induced transparency (EIT). Due to the small sub-natural width of the CPT and EIT resonances, they find wide applications in metrology, quantum optics, atom cooling. A non-compensated stray magnetic field (SMF) can change the shape and sign of the resonance or destroy it completely. In this work, we present an experimental and theoretical investigation of the influence of a stray magnetic field on the CPT resonances obtained on Zeeman sublevels of the D1 line of 87Rb in a paraffin-coated vacuum cell. The role is clarified of the polarization moments with different rank in creating the integral registered fluorescent signal in the presence of a stray magnetic field. It is shown that a transverse magnetic field plays an important role in changing the shape of the signal.

  8. Highly enhanced and temporally stable field emission from MWCNTs grown on aluminum coated silicon substrate

    SciTech Connect

    Sreekanth, M.; Ghosh, S. Patra, R.; Srivastava, P.

    2015-06-15

    In this work, a detailed field emission study of multi-walled carbon nanotubes (MWCNTs) grown on Si and Al coated Si substrates is reported. Morphological and microstructural studies of the films show higher entanglement of CNTs in the case of CNT/Si film as compared to CNT/Al/Si film. Raman studies show that the defect mediated peak (D) is substantially suppressed as compared to graphitic peak (G) resulting in significant reduction in I{sub D}/I{sub G} value in CNT/Al/Si film. Field emission (FE) current density of CNT/Al/Si film (∼25 mA/cm{sup 2}) is significantly higher as compared to that of CNT/Si film (∼1.6 mA/cm{sup 2}). A substantial improvement in temporal stability is also observed in CNT/Al/Si film. This enhancement in field emission current is attributed to strong adhesion between substrate and CNTs, low work function, high local field enhancement factor at the CNT tips and less entanglement of CNTs grown on Al/Si. The temporally stable CNT/Al/Si cold cathode can be a potential candidate to replace conventional electron sources in prototype devices.

  9. Highly enhanced and temporally stable field emission from MWCNTs grown on aluminum coated silicon substrate

    NASA Astrophysics Data System (ADS)

    Sreekanth, M.; Ghosh, S.; Patra, R.; Srivastava, P.

    2015-06-01

    In this work, a detailed field emission study of multi-walled carbon nanotubes (MWCNTs) grown on Si and Al coated Si substrates is reported. Morphological and microstructural studies of the films show higher entanglement of CNTs in the case of CNT/Si film as compared to CNT/Al/Si film. Raman studies show that the defect mediated peak (D) is substantially suppressed as compared to graphitic peak (G) resulting in significant reduction in ID/IG value in CNT/Al/Si film. Field emission (FE) current density of CNT/Al/Si film (˜25 mA/cm2) is significantly higher as compared to that of CNT/Si film (˜1.6 mA/cm2). A substantial improvement in temporal stability is also observed in CNT/Al/Si film. This enhancement in field emission current is attributed to strong adhesion between substrate and CNTs, low work function, high local field enhancement factor at the CNT tips and less entanglement of CNTs grown on Al/Si. The temporally stable CNT/Al/Si cold cathode can be a potential candidate to replace conventional electron sources in prototype devices.

  10. Gold-coated graphene field-effect transistors for quantitative analysis of protein-antibody interactions

    NASA Astrophysics Data System (ADS)

    Tarasov, Alexey; Tsai, Meng-Yen; Flynn, Erin M.; Joiner, Corey A.; Taylor, Robert C.; Vogel, Eric M.

    2015-12-01

    Field-effect transistors (FETs) based on large-area graphene and other 2D materials can potentially be used as low-cost and flexible potentiometric biological sensors. However, there have been few attempts to use these devices for quantifying molecular interactions and to compare their performance to established sensor technology. Here, gold-coated graphene FETs are used to measure the binding affinity of a specific protein-antibody interaction. Having a gold surface gives access to well-known thiol chemistry for the self-assembly of linker molecules. The results are compared with potentiometric silicon-based extended-gate sensors and a surface plasmon resonance system. The estimated dissociation constants are in excellent agreement for all sensor types as long as the active surfaces are the same (gold). The role of the graphene transducer is to simply amplify surface potential changes caused by adsorption of molecules on the gold surface.

  11. Stretching surfactant- or protein-coated droplets in a high frequency electric field

    NASA Astrophysics Data System (ADS)

    Randall, Greg

    2015-11-01

    Surfactant-stabilized and protein-coated droplets are stretched in a high-frequency AC electric field. This is the first work to study aqueous droplets stretching at a frequency (20 MHz) high enough that water behaves as a pure dielectric. Consequently, the water/oil system is free of steady electrohydrodynamic flow. The absence of a steady flow provides a potential way to measure interfacial rheological properties of water soluble additives with droplet stretching models. Results are presented for both the wide gap and thin gap geometries. Adding dilute protein additives (e.g. bovine serum albumin, switchable peptides, hydrophobins) to form interfacial elastic layers inhibits stretching, which is an important milestone in our efforts to engineer a continuous, uniform wall thickness shell production process. Work supported by General Atomics IR&D Funds.

  12. Line-patterning of polyaniline coated MWCNT on stepped substrates using DC electric field

    NASA Astrophysics Data System (ADS)

    Ko, Young Gun; Do, Tae Gu; Oh, Hyun Chul; Lee, Hyun Jeong; Han, Hung-Gu; Kim, Choong Hyun; Choi, Ung Su

    2014-10-01

    Printing electronic components on a chip edge and a stepped substrate with functional inks are an attractive approach for achieving flexible and inexpensive circuits for applications such as flexible displays and large-area chemo/bio/radioactivity sensors. However, it is still challenging because a sufficient cover of the 100 μm high step at the chip edge with a high-resolution pattern is the hardest part of the layer assembling by inkjet printing. Herein, we present a simple and effective strategy to generate electrically conductive line-patterns on stepped substrates by applying the DC electric field. On the surface of flat polyimide substrate, the fine line-pattern (less than 850 nm in line width) is achieved with a polyaniline coated MWCNT dispersed ink. Furthermore, 9.9 μm of line width is successfully patterned on the high stepped poly(dimethylsiloxane) substrate, higher than 100 μm, by printing only 1 time.

  13. Do joints initiate as sharp mode I fractures or finite thickness dilatancy bands? Insights from laboratory experiments and field data

    NASA Astrophysics Data System (ADS)

    Petit, J.; Chemenda, A. I.; Jorand, C.

    2011-12-01

    Terminology on fracture and discontinuities in geological objects mainly relies on distinguishing between tabular and sharp forms of deformation localization/failure structures (Aydin et al, JSG 2006; Shultz and Fossen, AAPG, 2009). On this basis joints (considered as mode I fractures) and dilation bands (very rarely observed) are distinguished among extension discontinuities. The former propagate with the separation of the fracture walls due to strong stress concentration at the fracture tips. The plumose features or hackles typical of joints (these terms cover a wide variety of diverging fractographic features) are believed to result from the fracture front breakdown due to the loading mode change (the origin of this change remains unclear). This view is called into question by recent experimental results of extension tests conducted on a synthetic physical rock analogue (granular, frictional, cohesive and dilatant) material (GRAM1) and by field observations of embryonic (not yet open) joints in highly jointed dolomicrite Chemenda et al., JGR, 2011). The initial porosity and grain size of both materials are very different, but at SEM scale, both experimental and natural unopened discontinuities reveal a comparable dilatancy (dilation) band structure with a porosity increase over a width of several grains. This suggests that the distinction between tabular and sharp is a matter of observation scale. Both axisymetric and poly-axial extension tests show that dilatancy bands form at elevated mean stress and have plumose morphology. Mode I cracking occurs only at very low mean stres and the forming fractures do not bear plumose features. Thus the absence of plumose structures can be considered as the signature of mode I fracturing. Consequently, we propose that non- plumose bearing natural joints (provided their fractography is not eroded) could originate as mode I fractures and call them "mode I joints". We call the joints formed as closed dilatancy bands propagating

  14. Sensorimotor Results from the Joint NASA and Russian Pilot Field Test

    NASA Technical Reports Server (NTRS)

    Reschke, Millard; Kozlovskaya, I. B.; Kofman, I. S.; Tomilovskaya, E. S.; Cerisano, J. M.; Bloomberg, J. J.; Stenger, M. B.; Lee, S. M. C.; Laurie, S. S.; Rukavishnikov, I. V.; Fomina, E. V.; Wood, S. J.; Mulavara, A. P.; Feiveson, A. H.; Fisher, E. A.; Rosenberg, M. J. F.; Kitov, V. V.; Lysova, N. Yu

    2016-01-01

    Testing of crew responses following long-duration flights has not previously been possible until a minimum of 24 hours after landing. As a result, it has not been possible to estimate the nonlinear trend of the early (<24 hours) recovery process, nor has it been possible to accurately assess the full impact of the decrements associated with long-duration flight. To overcome these limitations, both the Russian and U.S. programs have implemented testing at the Soyuz landing site. This research effort has been identified as the Field Test (FT). For operational reasons the FT has been divided into two phases: the full FT and a preliminary pilot version (PFT) of the FT that is reduced in both length and scope. The PFT has now been completed with the landing of the crew of International Space Station Increment 42/43 (Soyuz expedition 41S). RESEARCH: The primary goal of this research was to determine functional abilities associated with long-duration space flight crews beginning as soon after landing as possible (< 2 hours) with an additional two follow-up measurement sessions within 24 hours after landing. This study goal has both sensorimotor and cardiovascular elements. The PFT represented a initial evaluation of the feasibility of testing in the field and was comprised of a jointly agreed upon subset of tests drawn from the full FT and relied heavily on Russia's Institute of Biomedical Problems Sensory-Motor and Countermeasures Department for content and implementation. Data from the PFT was collected following several ISS missions. Testing on the U.S. side has included: (1) a sit-to-stand test, (2) recovery from a fall stand test where the crewmember begins in the prone position on the ground and then stands for 3.5 minutes while cardiovascular performance and postural ataxia data are acquired, and (3) a tandem heel-to-toe walk test to determine changes in the central locomotor program. Video, cardiovascular parameters (heart rate and blood pressure), data from body

  15. Design and implementation of coating hardware for the Hobby-Eberly Telescope wide-field corrector

    NASA Astrophysics Data System (ADS)

    Good, John; Lee, Hanshin; Hill, Gary J.; Vattiat, Brian; Perry, David; Kriel, Herman; Savage, Richard

    2014-07-01

    A major upgrade of the HET is in progress that will substantially increase the pupil size to 10 meters and the field of view to 22 arc-minutes by replacing the spherical aberration corrector. The new Wide Field Corrector is a 4-element assembly weighing 750kg and measuring 1.34 meters diameter by 2.1 meter in length. Special fixtures were required in order to support the mirrors of the Wide-Field Corrector and adapt them to the coaters chamber, during the vacuum coating process. For the 1 meter-class mirrors, the only suitable support interface was located on a 80mm wide cylindrical surface on the periphery of each mirror. The vacuum compatible system had to support the mirrors with the surface facing downward, and accommodate thermal ranges from ambient to 100C without inducing stresses in the substrate. The fixture also had to accommodate washing, as well as support of witness samples during testing and production runs, and provide masking for alignment fixtures in the center apertures of each mirror. Design principles, materials, implementation details, as well as lessons learned are covered*.

  16. Iron coated sand/glauconite filters for phosphorus removal from artificially drained agricultural fields

    NASA Astrophysics Data System (ADS)

    Vandermoere, Stany; De Neve, Stefaan

    2016-04-01

    Flanders (Belgium) is confronted with reactive phosphorus concentrations in streams and lakes which are three to four times higher than the 0.1 ppm P limit set by the Water Framework Directive. Much of the excessive P input in surface waters is derived from agriculture. Direct P input from artificially drained fields (short-circuiting the buffering capacity of the subsoil) is suspected to be one of the major sources. We aim to develop simple and cheap filters that can be directly installed in the field to reduce P concentration from the drain water. Here we report on the performance of such filters tested at lab scale. As starting materials for the P filter, iron coated sand and acid pre-treated glauconite were used. These materials, both rich in Fe, were mixed in ratios of 75/25, 65/35, 50/50 and 0/100 (iron coated sand/glauconite ratio based on weight basis) and filled in plastic tubes. A screening experiment using the constant head method with a 0.01 M CaCl2 solution containing 1 ppm P showed that all four types of mixtures reduced the P concentration in the outflowing water to almost zero, and that the 75/25, 65/35 and 0/100 mixtures had a sufficiently large hydraulic conductivity of 0.9 to 6.0 cm/min, while the hydraulic conductivity of the 50/50 mixture was too low (< 0.4 cm/min). In a second experiment the iron coated sand and acid pre-treated glauconite were mixed in ratios of 75/25, 65/35 and 0/100 and filled in the same plastic tubes as in the first experiment. Subsequently a 0.01 M CaCl2 solution containing 1 ppm P was passed through the filters over several days, in amounts equivalent to half of the yearly water volume passing through the drains. This experiment firstly showed that in all cases the hydraulic conductivity fluctuated strongly: it decreased from 4.0-6.0 cm/min to 2.0-1.5 cm/min for the 75/25 filter, and to values < 0.4 cm/min for the 65/35 filter, whereas it increased from 0.8 to 1.4 cm/min for the 0/100 filter. Secondly, we observed a

  17. Urban runoff treatment using nano-sized iron oxide coated sand with and without magnetic field applying

    PubMed Central

    2013-01-01

    Increase of impervious surfaces in urban area followed with increases in runoff volume and peak flow, leads to increase in urban storm water pollution. The polluted runoff has many adverse impacts on human life and environment. For that reason, the aim of this study was to investigate the efficiency of nano iron oxide coated sand with and without magnetic field in treatment of urban runoff. In present work, synthetic urban runoff was treated in continuous separate columns system which was filled with nano iron oxide coated sand with and without magnetic field. Several experimental parameters such as heavy metals, turbidity, pH, nitrate and phosphate were controlled for investigate of system efficiency. The prepared column materials were characterized with Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray analysis (EDXA) instruments. SEM and EDXA analyses proved that the sand has been coated with nano iron oxide (Fe3O4) successfully. The results of SEM and EDXA instruments well demonstrate the formation of nano iron oxide (Fe3O4) on sand particle. Removal efficiency without magnetic field for turbidity; Pb, Zn, Cd and PO4 were observed to be 90.8%, 73.3%, 75.8%, 85.6% and 67.5%, respectively. When magnetic field was applied, the removal efficiency for turbidity, Pb, Zn, Cd and PO4 was increased to 95.7%, 89.5%, 79.9%, 91.5% and 75.6% respectively. In addition, it was observed that coated sand and magnetic field was not able to remove NO3 ions. Statistical analyses of data indicated that there was a significant difference between removals of pollutants in two tested columns. Results of this study well demonstrate the efficiency of nanosized iron oxide-coated sand in treatment of urban runoff quality; upon 75% of pollutants could be removed. In addition, in the case of magnetic field system efficiency can be improved significantly. PMID:24360061

  18. Pilot Sensorimotor and Cardiovascular Results from the Joint Russian/U.S. Field Test

    NASA Technical Reports Server (NTRS)

    Reschke, M. F.; Kozlovskaya, I. B.; Kofman, I. S.; Tomilovskya, E. S.; Cerisano, J. M.; Bloomberg, J. J.; Stenger, M. B.; Platts, S. H.; Rukavishnikov, I. V.; Fomina, E. V.; Lee, S. M. C.; Wood, S. J.; Mulavara, A. P.; Feiveson, A. H.; Fisher, E. A.

    2014-01-01

    The primary goal of this research is to determine functional abilities associated with long-duration space flight crews beginning as soon after landing as possible (< 2 hours) with an additional two follow-up measurements sessions on the day of landing. This goal has both sensorimotor and cardiovascular elements, including evaluations of NASA's new anti-orthostatic compression garment and the Russian Kentavr garment. Functional sensorimotor measurements will include, but are not limited to, assessing hand/eye coordination, standing from a seated position (sit-to-stand), walking normally without falling, measurement of dynamic visual acuity, discriminating different forces generated with both the hands and legs, recovering from a fall (standing from a prone position), coordinated walking involving tandem heel-to-toe placement, and determining postural ataxia while standing. The cardiovascular portion of the investigation includes measuring blood pressure and heart rate during a timed stand test in conjunction with postural ataxia testing (quiet stance sway) as well as cardiovascular responses during the other functional tasks. In addition to the immediate post-landing collection of data for the full FT, postflight data is being acquired twice more within the 24 hours after landing and will continue over the subsequent weeks until functional sensorimotor and cardiovascular responses have returned to preflight normative values. The PFT represents a initial evaluation of the feasibility of testing in the field, and is comprised of a jointly agreed upon subset of tests from the full FT and relies heavily on Russia's Institute of Biomedical Problems Sensory-Motor and Countermeasures Laboratories for content and implementation. The PFT has been collected on several ISS missions. Testing on the U.S. side has included: (1) a sit-to-stand test, (2) recovery from a fall where the crewmember began in the prone position on the ground and then stood for 3 minutes while

  19. Enhanced field emission from cerium hexaboride coated multiwalled carbon nanotube composite films: A potential material for next generation electron sources

    SciTech Connect

    Patra, Rajkumar; Ghosh, S.; Sheremet, E.; Rodriguez, R. D.; Lehmann, D.; Gordan, O. D.; Zahn, D. R. T.; Jha, M.; Ganguli, A. K.; Schmidt, H.; Schulze, S.; Schmidt, O. G.

    2014-03-07

    Intensified field emission (FE) current from temporally stable cerium hexaboride (CeB{sub 6}) coated carbon nanotubes (CNTs) on Si substrate is reported aiming to propose the new composite material as a potential candidate for future generation electron sources. The film was synthesized by a combination of chemical and physical deposition processes. A remarkable increase in maximum current density, field enhancement factor, and a reduction in turn-on field and threshold field with comparable temporal current stability are observed in CeB{sub 6}-coated CNT film when compared to pristine CeB{sub 6} film. The elemental composition and surface morphology of the films, as examined by scanning electron microscopy, transmission electron microscopy, and energy dispersive X-ray measurements, show decoration of CeB{sub 6} nanoparticles on top and walls of CNTs. Chemical functionalization of CNTs by the incorporation of CeB{sub 6} nanoparticles is evident by a remarkable increase in intensity of the 2D band in Raman spectrum of coated films as compared to pristine CeB{sub 6} films. The enhanced FE properties of the CeB{sub 6} coated CNT films are correlated to the microstructure of the films.

  20. Alkali-vapor cell with metal coated windows for efficient application of an electric field

    NASA Astrophysics Data System (ADS)

    Sarkisyan, D.; Sarkisyan, A. S.; Guéna, J.; Lintz, M.; Bouchiat, M.-A.

    2005-05-01

    We describe the implementation of a cylindrical T-shaped alkali-vapor cell for laser spectroscopy in the presence of a longitudinal electric field. The two windows are used as two electrodes of the high-voltage assembly, which is made possible by a metallic coating which entirely covers the inner and outer sides of the windows except for a central area to let the laser beams in and out of the cell. This allows very efficient application of the electric field, up to 2kV/cm in a rather dense superheated vapor, even when significant photoemission takes place at the windows during pulsed laser irradiation. The body of the cell is made of sapphire or alumina ceramic to prevent large currents resulting from surface conduction observed in cesiated glass cells. The technique used to attach the monocrystalline sapphire windows to the cell body causes minimal stress birefringence in the windows. In addition, reflection losses at the windows can be made very small. The vapor cell operates with no buffer gas and has no magnetic part. The use of this kind of cell has resulted in an improvement of the signal-to-noise ratio in the measurement of parity violation in cesium vapor underway at ENS, Paris. The technique can be applied to other situations where a brazed assembly would give rise to unacceptably large birefringence in the windows.

  1. Joint influences of aerodynamic flow field and aerodynamic heating of the dome on imaging quality degradation of airborne optical systems.

    PubMed

    Xiao, Haosu; Zuo, Baojun; Tian, Yi; Zhang, Wang; Hao, Chenglong; Liu, Chaofeng; Li, Qi; Li, Fan; Zhang, Li; Fan, Zhigang

    2012-12-20

    We investigated the joint influences exerted by the nonuniform aerodynamic flow field surrounding the optical dome and the aerodynamic heating of the dome on imaging quality degradation of an airborne optical system. The Spalart-Allmaras model provided by FLUENT was used for flow computations. The fourth-order Runge-Kutta algorithm based ray tracing program was used to simulate optical transmission through the aerodynamic flow field and the dome. Four kinds of imaging quality evaluation parameters were presented: wave aberration of the exit pupil, point spread function, encircled energy, and modulation transfer function. The results show that the aero-optical disturbance of the aerodynamic flow field and the aerodynamic heating of the dome significantly affect the imaging quality of an airborne optical system. PMID:23262604

  2. Exact results for the local fields and the effective moduli of fibrous composites with thickly coated fibers

    NASA Astrophysics Data System (ADS)

    Benveniste, Y.

    2014-11-01

    Fibrous composites that consist of thickly coated cylindrical fibers embedded in a matrix are considered. All of the three phases of the composite are assumed to be transversely isotropic. The study consists of three parts. In the first part exact relations are derived for the influence functions that connect applied uniform overall fields to the induced local fields in piezomagnetoelectric systems. We consider the case of coated fibers with a concentrically circular cross section, and contrast the derived relations with the more limited ones that could be obtained in the case of coated fibers with an arbitrary cross section. The derivation is based on the ability to create uniform strain, electric and magnetic fields in the composite by the application of certain mechanical, electric, magnetic and thermal loadings. In the second part of the study, exact microstructure-independent connections are derived for a subgroup of the effective moduli of the homogenized piezomagnetoelectric composite which exhibits overall transverse isotropy. In the third part of the study, the derived exact connections between the effective moduli are reduced to the setting of thermoelasticity; allowing the coating to be thin and highly stiff or highly compliant, we make contact with the exact connections derived lately in the literature for two-phase fibrous thermoelastic composites with surface-stress-type and spring-type imperfect interfaces.

  3. ITPA Joint Experiment to Measure Threshold E-fields and Densities for Runaway Electron Onset and Suppression

    NASA Astrophysics Data System (ADS)

    Granetz, Robert

    2013-10-01

    Recent results from an ITPA joint experiment to study the onset, growth, and decay of relativistic electrons (REs) indicate that energy loss mechanisms other than collisional damping may play a dominant role in the dynamics of the RE population. Understanding the physics of RE growth and mitigation is motivated by the theoretical prediction that disruptions of full-current ITER discharges could generate ~10 MA of REs (10-20 MeV) through an avalanche growth process. A necessary condition for avalanche growth is that the Coulomb acceleration due to the toroidal electric field has to be at least high enough to counter the collisional drag on background electrons, i.e. E>Ec, where Ec is the critical E-field derived in. Ec scales linearly with electron density, ne, so one way to suppress avalanche growth is to quickly raise ne sufficiently high, but this is problematic on ITER. However, if there are other energy loss mechanisms in addition to collisions, then the actual threshold E-field will be greater than Ec, i.e. REs become more difficult to generate and sustain due to the additional loss mechanism(s). Due to the importance of Ec to the issue of REs in ITER, the ITPA MHD group is conducting a joint experiment to measure the threshold E-field on a number of tokamaks under steady-state, low Zeff conditions in which Vloop , ne, and REs can be well-diagnosed, and compared to theory. The analysis must take into account the RE growth time, which can be comparable to the discharge timescale. Data from DIII-D, C-Mod, TEXTOR, and FTU have been obtained so far, and the consensus to date is that the threshold E-field is significantly higher than Ec, or conversely, the ne required to damp REs is significantly less than predicted, suggesting that other loss mechanisms are involved. Implications for RE mitigation in ITER will be discussed.

  4. RAPID COMMUNICATION: Effect of strain, magnetic field and field angle on the critical current density of Y Ba2Cu3O7-δ coated conductors

    NASA Astrophysics Data System (ADS)

    van der Laan, D. C.; Ekin, J. W.; Douglas, J. F.; Clickner, C. C.; Stauffer, T. C.; Goodrich, L. F.

    2010-07-01

    A large, magnetic-field-dependent, reversible reduction in critical current density with axial strain in Y Ba2Cu3O7-δ coated conductors at 75.9 K has been measured. This effect may have important implications for the performance of Y Ba2Cu3O7-δ coated conductors in applications where the conductor experiences large stresses in the presence of a magnetic field. Previous studies have been performed only under tensile strain and could provide only a limited understanding of the in-field strain effect. We now have constructed a device for measuring the critical current density as a function of axial compressive and tensile strain and applied magnetic field as well as magnetic field angle, in order to determine the magnitude of this effect and to create a better understanding of its origin. The reversible reduction in critical current density with strain becomes larger with increasing magnetic field at all field angles. At 76 K the critical current density is reduced by about 30% at - 0.5% strain when a magnetic field of 5 T is applied parallel to the c-axis of the conductor or 8 T is applied in the ab-plane, compared to a reduction of only 13% in self-field. Differences in the strain response of the critical current density at various magnetic field angles indicate that the pinning mechanisms in Y Ba2Cu3O7-δ coated conductors are uniquely affected by strain. Contribution of NIST, not subject to US copyright.

  5. Method for reinforcing tubing joints

    NASA Technical Reports Server (NTRS)

    Kinzler, J.; Lee, W. S.

    1968-01-01

    Joint repair technique uses a longitudinally split aluminum shield over the joint ferrule and immediately adjacent tubing to reseal or reinforce leaking or weak joints in small tubing. Epoxy resin coating on inside surfaces of the two shield halves provides a tightly sealed bond between shield and tubing.

  6. Development of compact 500 kV 8000 A gas insulated transmission line-dust control during field jointing and method for detecting conductive particles

    SciTech Connect

    Kaminaga, K.; Koshiishi, M.; Hayashi, T.; Matsuki, M.; Hara, T.; Sugiyama, N.

    1987-10-01

    This paper describes the results of studies made on dust control during field jointing and a method for detecting conductive particles after installation in the development of a compact 500 kV 8000 A gas insulated transmission line (GIL). The study on dust control during field jointing proved that field jointing of the compact GIL can be done like conventional GIL in an easily fabricated vinyl shelter without a clean air flow. Harmful conductive particles can be detected with an Acoustic Emission (AE) sensor. This sensor is effective in improving the reliability of the compact GIL when used with a suitable ac voltage during field test. A 120 m long test line of compact 500 kV 8000 A GIL was constructed and, in a long-term field test, proved to have properties sufficient for practical use.

  7. Line-patterning of polyaniline coated MWCNT on stepped substrates using DC electric field.

    PubMed

    Ko, Young Gun; Do, Tae Gu; Gu, Tae; Oh, Hyun Chul; Lee, Hyun Jeong; Han, Hung-gu; Kim, Choong Hyun; Choi, Ung Su

    2014-01-01

    Printing electronic components on a chip edge and a stepped substrate with functional inks are an attractive approach for achieving flexible and inexpensive circuits for applications such as flexible displays and large-area chemo/bio/radioactivity sensors. However, it is still challenging because a sufficient cover of the 100 μm high step at the chip edge with a high-resolution pattern is the hardest part of the layer assembling by inkjet printing. Herein, we present a simple and effective strategy to generate electrically conductive line-patterns on stepped substrates by applying the DC electric field. On the surface of flat polyimide substrate, the fine line-pattern (less than 850 nm in line width) is achieved with a polyaniline coated MWCNT dispersed ink. Furthermore, 9.9 μm of line width is successfully patterned on the high stepped poly(dimethylsiloxane) substrate, higher than 100 μm, by printing only 1 time. PMID:25325776

  8. Neonicotinoid-Coated Zea mays Seeds Indirectly Affect Honeybee Performance and Pathogen Susceptibility in Field Trials

    PubMed Central

    Alburaki, Mohamed; Boutin, Sébastien; Mercier, Pierre-Luc; Loublier, Yves; Chagnon, Madeleine; Derome, Nicolas

    2015-01-01

    Thirty-two honeybee (Apis mellifera) colonies were studied in order to detect and measure potential in vivo effects of neonicotinoid pesticides used in cornfields (Zea mays spp) on honeybee health. Honeybee colonies were randomly split on four different agricultural cornfield areas located near Quebec City, Canada. Two locations contained cornfields treated with a seed-coated systemic neonicotinoid insecticide while the two others were organic cornfields used as control treatments. Hives were extensively monitored for their performance and health traits over a period of two years. Honeybee viruses (brood queen cell virus BQCV, deformed wing virus DWV, and Israeli acute paralysis virus IAPV) and the brain specific expression of a biomarker of host physiological stress, the Acetylcholinesterase gene AChE, were investigated using RT-qPCR. Liquid chromatography-mass spectrometry (LC-MS) was performed to detect pesticide residues in adult bees, honey, pollen, and corn flowers collected from the studied hives in each location. In addition, general hive conditions were assessed by monitoring colony weight and brood development. Neonicotinoids were only identified in corn flowers at low concentrations. However, honeybee colonies located in neonicotinoid treated cornfields expressed significantly higher pathogen infection than those located in untreated cornfields. AChE levels showed elevated levels among honeybees that collected corn pollen from treated fields. Positive correlations were recorded between pathogens and the treated locations. Our data suggests that neonicotinoids indirectly weaken honeybee health by inducing physiological stress and increasing pathogen loads. PMID:25993642

  9. Neonicotinoid-Coated Zea mays Seeds Indirectly Affect Honeybee Performance and Pathogen Susceptibility in Field Trials.

    PubMed

    Alburaki, Mohamed; Boutin, Sébastien; Mercier, Pierre-Luc; Loublier, Yves; Chagnon, Madeleine; Derome, Nicolas

    2015-01-01

    Thirty-two honeybee (Apis mellifera) colonies were studied in order to detect and measure potential in vivo effects of neonicotinoid pesticides used in cornfields (Zea mays spp) on honeybee health. Honeybee colonies were randomly split on four different agricultural cornfield areas located near Quebec City, Canada. Two locations contained cornfields treated with a seed-coated systemic neonicotinoid insecticide while the two others were organic cornfields used as control treatments. Hives were extensively monitored for their performance and health traits over a period of two years. Honeybee viruses (brood queen cell virus BQCV, deformed wing virus DWV, and Israeli acute paralysis virus IAPV) and the brain specific expression of a biomarker of host physiological stress, the Acetylcholinesterase gene AChE, were investigated using RT-qPCR. Liquid chromatography-mass spectrometry (LC-MS) was performed to detect pesticide residues in adult bees, honey, pollen, and corn flowers collected from the studied hives in each location. In addition, general hive conditions were assessed by monitoring colony weight and brood development. Neonicotinoids were only identified in corn flowers at low concentrations. However, honeybee colonies located in neonicotinoid treated cornfields expressed significantly higher pathogen infection than those located in untreated cornfields. AChE levels showed elevated levels among honeybees that collected corn pollen from treated fields. Positive correlations were recorded between pathogens and the treated locations. Our data suggests that neonicotinoids indirectly weaken honeybee health by inducing physiological stress and increasing pathogen loads. PMID:25993642

  10. Counterintuitive energy shifts in joint electron-nuclear-energy spectra of strong-field fragmentation of H2+

    NASA Astrophysics Data System (ADS)

    Wang, Zhuo; Li, Min; Zhou, Yueming; Li, Yang; Lan, Pengfei; Lu, Peixiang

    2016-01-01

    By numerically solving the time-dependent Schrödinger equation, we investigate electron-nuclear-energy sharing in strong-field fragmentation of the H2+ molecule. We find a counterintuitive energy shift in the joint electron-nuclear-energy spectrum. This energy shift becomes larger for lower nuclear energies. Through tracing the time evolution of the electron wave packet of bound states, we identify that the energy shift originates from the Stark effect due to the coupling of the ground state and the first exited state of the H2+ molecule in strong laser fields. We achieve a good agreement between the ab initio result and the analytic method that includes the Stark effect of molecules.

  11. Design of A Large Oxide Coated Cathode Plasma Source for Operation in High Magnetic Fields at the New LAPD

    NASA Astrophysics Data System (ADS)

    Leneman, David

    2001-10-01

    We use a Barium Oxide coated cathode to supply accelerated electrons as an energy source to from our plasma. Oxide coated cathodes have been used for decades in vacuum tubes and plasma research. Most of these have been small (1 cm dia.) or designed to operate in a low magnetic field where the J×B \\unboldmath forces on them are negligible. At the new LAPD we will have large diameter plasma sources at both ends of the machine which must operate in a 3.5 kG ambient magnetic field. We have designed and built one such source which is 72 cm in diameter. It will supply up to 20 kA of pulsed beam current and uses a 1 m by 1 m, 2.5 kA (dc), 150 kW heater. Solutions to various engineering issues will be discussed. These pertain to differential thermal expansion over 1 m distances, J×B \\unboldmath forces on the heater and cathode, heat containment and uniformity of the oxide coating and of plasma production. These issues are important to any experimenter who plans to build an oxide coated plasma source.

  12. Observations of flux motion in niobium films. [study of magnetic field trapped in superconducting coatings of gyroscope rotor

    NASA Technical Reports Server (NTRS)

    Xiao, Y. M.; Keiser, G. M.

    1991-01-01

    A magnetic field trapped in a superconducting sphere was examined at temperatures from 4.6 K to 5.5 K. The sphere was the rotor of a precision gyroscope and was made of fused quartz and coated with a sputtered niobium film. The rotor diameter was 3.8 cm. The film thickness was 2.5 microns. The tests were carried out at an ambient magnetic field of about 1 mG. Unexpected instability of the trapped field was observed. The experimental results and possible explanations are presented.

  13. Strain concentrations in pipelines with concrete coating full scale bending tests and analytical calculations

    SciTech Connect

    Verley, R.; Ness, O.B.

    1995-12-31

    This paper presents the results of full scale bending tests on 16 in. and 20 in. diameter, concrete coated pipes with polyethene and asphalt corrosion coatings. Constant moment, four-point bending was applied to a pipe string consisting of one pipe joint welded between two half-length joints. The strain concentration factor (SCF) at the field joints (FJ), expressing the ratio between the strain in the FJ and the average strain for the pipe joint, was investigated and compared to predictions using an analytical model presented in an accompanying paper (Ness and Verley, 1995). Material tests on the pipe steel, the corrosion coating and the concrete were conducted. The analytical model is found to give a good prediction of the strain distribution along the pipe joint, for both the steel and the concrete, and therefore also of the SCF. The sliding of the concrete over the steel is also predicted reasonably well.

  14. MISR JOINT_AS Data

    Atmospheric Science Data Center

    2014-07-21

    Joint Aerosol Product (JOINT_AS) The MISR Level 3 Products are global or regional ... field campaigns at daily and monthly time scales. The Joint Aerosol product provides a monthly global statistical summary of MISR ...

  15. An equation for the quench propagation velocity valid for high field magnet use of REBCO coated conductors

    NASA Astrophysics Data System (ADS)

    Bonura, M.; Senatore, C.

    2016-06-01

    Based on a study of the thermophysical properties, we derived a practical formula for the normal zone propagation velocity appropriate for REBa2Cu3O7-x coated conductors in high magnetic fields. An analytical expression to evaluate the current sharing temperature as a function of the operating conditions is also proposed. The presented study has allowed us to account for experimental results not fully understood in the framework of the models widely used in the literature. In particular, we provided a fundamental understanding of the experimental evidence that the normal zone propagation velocity in REBa2Cu3O7-x coated conductors can be mainly determined by the operating current, regardless of the applied field and temperature.

  16. Spatial resolution and switching field of magnetic force microscope tips prepared by coating Fe/Co-Pt layers

    NASA Astrophysics Data System (ADS)

    Nagatsu, Ryo; Ohtake, Mitsuru; Futamoto, Masaaki; Kirino, Fumiyoshi; Inaba, Nobuyuki

    2016-05-01

    Magnetic force microscope tips are prepared by coating Si tips of 4 nm radius with magnetic bi-layer film consisting of soft magnetic material of Fe(x nm) and hard magnetic material Co-Pt alloy (20-x nm), 0 ≤ x ≤ 20. The effects of layer thickness ratio and stacking sequence on the spatial resolution and the switching field are investigated. Higher resolutions are observed for tips prepared by coating Co-Pt alloy followed by Fe film deposition compared with those prepared by employing the opposite deposition sequence. The resolution improves from 11.0 to 8.2 nm whereas the switching field decreases from 1525 to 475 Oe with increasing the x value from 0 to 20 nm. The present study has shown a possibility of tuning MFM tip performance by employing a soft/hard dual layer structure.

  17. Automated bone segmentation from large field of view 3D MR images of the hip joint

    NASA Astrophysics Data System (ADS)

    Xia, Ying; Fripp, Jurgen; Chandra, Shekhar S.; Schwarz, Raphael; Engstrom, Craig; Crozier, Stuart

    2013-10-01

    Accurate bone segmentation in the hip joint region from magnetic resonance (MR) images can provide quantitative data for examining pathoanatomical conditions such as femoroacetabular impingement through to varying stages of osteoarthritis to monitor bone and associated cartilage morphometry. We evaluate two state-of-the-art methods (multi-atlas and active shape model (ASM) approaches) on bilateral MR images for automatic 3D bone segmentation in the hip region (proximal femur and innominate bone). Bilateral MR images of the hip joints were acquired at 3T from 30 volunteers. Image sequences included water-excitation dual echo stead state (FOV 38.6 × 24.1 cm, matrix 576 × 360, thickness 0.61 mm) in all subjects and multi-echo data image combination (FOV 37.6 × 23.5 cm, matrix 576 × 360, thickness 0.70 mm) for a subset of eight subjects. Following manual segmentation of femoral (head-neck, proximal-shaft) and innominate (ilium+ischium+pubis) bone, automated bone segmentation proceeded via two approaches: (1) multi-atlas segmentation incorporating non-rigid registration and (2) an advanced ASM-based scheme. Mean inter- and intra-rater reliability Dice's similarity coefficients (DSC) for manual segmentation of femoral and innominate bone were (0.970, 0.963) and (0.971, 0.965). Compared with manual data, mean DSC values for femoral and innominate bone volumes using automated multi-atlas and ASM-based methods were (0.950, 0.922) and (0.946, 0.917), respectively. Both approaches delivered accurate (high DSC values) segmentation results; notably, ASM data were generated in substantially less computational time (12 min versus 10 h). Both automated algorithms provided accurate 3D bone volumetric descriptions for MR-based measures in the hip region. The highly computational efficient ASM-based approach is more likely suitable for future clinical applications such as extracting bone-cartilage interfaces for potential cartilage segmentation.

  18. Automated bone segmentation from large field of view 3D MR images of the hip joint.

    PubMed

    Xia, Ying; Fripp, Jurgen; Chandra, Shekhar S; Schwarz, Raphael; Engstrom, Craig; Crozier, Stuart

    2013-10-21

    Accurate bone segmentation in the hip joint region from magnetic resonance (MR) images can provide quantitative data for examining pathoanatomical conditions such as femoroacetabular impingement through to varying stages of osteoarthritis to monitor bone and associated cartilage morphometry. We evaluate two state-of-the-art methods (multi-atlas and active shape model (ASM) approaches) on bilateral MR images for automatic 3D bone segmentation in the hip region (proximal femur and innominate bone). Bilateral MR images of the hip joints were acquired at 3T from 30 volunteers. Image sequences included water-excitation dual echo stead state (FOV 38.6 × 24.1 cm, matrix 576 × 360, thickness 0.61 mm) in all subjects and multi-echo data image combination (FOV 37.6 × 23.5 cm, matrix 576 × 360, thickness 0.70 mm) for a subset of eight subjects. Following manual segmentation of femoral (head-neck, proximal-shaft) and innominate (ilium+ischium+pubis) bone, automated bone segmentation proceeded via two approaches: (1) multi-atlas segmentation incorporating non-rigid registration and (2) an advanced ASM-based scheme. Mean inter- and intra-rater reliability Dice's similarity coefficients (DSC) for manual segmentation of femoral and innominate bone were (0.970, 0.963) and (0.971, 0.965). Compared with manual data, mean DSC values for femoral and innominate bone volumes using automated multi-atlas and ASM-based methods were (0.950, 0.922) and (0.946, 0.917), respectively. Both approaches delivered accurate (high DSC values) segmentation results; notably, ASM data were generated in substantially less computational time (12 min versus 10 h). Both automated algorithms provided accurate 3D bone volumetric descriptions for MR-based measures in the hip region. The highly computational efficient ASM-based approach is more likely suitable for future clinical applications such as extracting bone-cartilage interfaces for potential cartilage segmentation. PMID:24077264

  19. Strain concentrations in pipelines with concrete coating

    SciTech Connect

    Ness, O.B.; Verley, R.

    1996-08-01

    This paper concerns the strain distribution, and in particular strain concentration in field joints, for concrete-covered pipelines during laying. A semi-analytical model, full-scale tests to verify the model, and results of a parameter study are described. The model is used to establish nonlinear moment-curvature curves at a number of cross sections on the concrete-coated pipe and in the field joint (FJ). These are used to establish a strain concentration factor (SCF) for the FJ, or characteristics for a varying stiffness model of a pipe for direct use in lay analyses. Constant moment, four-point bending tests have been conducted on 16-in and 20-in dia, concrete-coated pipes as well as material tests on the pipe steel, corrosion coating and concrete. The behavior of the pipe, and in particular the SCF at the field joints, is investigated and compared to predictions using the semi-analytical model. The model is found to give a good prediction of the SCF and strain distribution along the pipe joint, for both the steel and the concrete, and is suitable for use in lay analyses for the overbend of S-mode lay vessels.

  20. Distribution patterns of MCA-coated granules aerially applied to corn fields of Southern Hungary between 2000 and 2002.

    PubMed

    Wennemann, L; Hummel, H E

    2003-01-01

    Field studies in corn (Zea mays L.) were conducted to evaluate distribution patterns of 4-methoxy-cinnamaldehyde (MCA) coated corn grits after aerial application with a Dromader fixed wing aircraft. The kairomone mimic MCA is synthetically available and a quite specific and efficient adult attractant for the invasive alien maize pest western corn rootworm (WCR) Diabrotica virgifera virgifera LeConte. Orientation disruptive properties of MCA for WCR when applied at unphysiologically high concentrations are currently under investigation. For successful implementation of the MCA disruption technique, the distribution patterns of MCA coated corn granules ('grits') in the field are important. Grits are degrained corn cobs, shredded to different sizes, coated with MCA and used as a carrier material to disseminate MCA vapors into corn fields. Granules of 10-12 mesh size were aerially applied eight times at rates ranging from 12.4 to 25.0 kg/ha. The goal is to evaluate distribution patterns of corn grits treated with MCA in three fields located at Csanadpalota, Kardoskút and Mezöhegyes in Southern Hungary between 2000 and 2002. Increasing rates reflect our attempts in finding and optimising the most even distribution of granules in the field. Field experiments were evaluated by collecting grits in 30-cm plastic saucers and by counting grits accumulated on corn plant parts. Variation in grit number per unit area and frequency of corn granule number per plant showed some transient technical application problems. Analysis of grits collected in the saucers revealed some statistical difference between the different application dates as well as differences in rates applied. Altogether grits in saucers were more evenly distributed in comparison to the grits collected on plant parts. As the corn plants age, their leaves and whorls present a smaller and smaller surface area where granules can accumulate. Altogether, however, grit distribution patterns indicate that aerial

  1. Development of Long Coated Conductors with High In-field Ic Performance by PLD Method at High Production Rate

    NASA Astrophysics Data System (ADS)

    Ibi, Akira; Yoshida, Tomo; Izumi, Teruo; Shiohara, Yuh; Yokoe, Daisaku; Kato, Takeharu; Hirayama, Tsukasa

    We fabricated short samples and a 93 m long coated conductor (C. C.) of EuBa2Cu3O7-δ (EuBCO) with BaHfO3 (BHO) by the IBAD and the PLD methods, which exhibited the high in-field minimum Ic value, (Ic(min)), performance of 141.2 (77 K in 3 T) and 411.3 (65 K in 3 T) A/cm-w for a short sample, and 133.9 (77 K in 3 T) A/cm-w for 93 m long C. C. with 3.6 μm in thickness, respectively. Moreover, this long EuBCO with BHO coated conductor also showed high uniform longitudinal Ic distributions and n-value in magnetic fields. However, the deposition rate for obtaining the high in-field Ic performance was comparatively slow down to 10 μm/h. To realize the low production cost for EuBCO with BHO coated conductors, improvement of the deposition rate of the EuBCO with BHO layer with high Ic is required. To solve this problem, we optimized growth conditions including deposition conditions. One of the objectives of this work was changing the layer growth mode from the vapor-solid (VS) mode to the vapor-liquid-solid (VLS) one to fabricate EuBCO with BHO layers for achievement of high production rate and maintaining the high in-field Ic and Jc performance of the films deposited at slow deposition rates. As a result, we fabricated EuBCO with BHO coated conductors at a high deposition rate of about 40 μm/h and production rate of about 10 m/h, which revealed the Ic(min) value of 48.7 A/cm-w at 77 K in 3 T for 1.35 μm in thickness.

  2. On unique determination of partially coated polyhedral scatterers with far field measurements

    NASA Astrophysics Data System (ADS)

    Liu, Hongyu; Zou, Jun

    2007-02-01

    This work is a continuation of our early study in Liu and Zou (2006 Uniqueness in an inverse acoustic obstacle scattering problem for both sound-hard and sound-soft polyhedral scatterers Inverse Problems 22 515-24 2006 Uniqueness in determining multiple polygonal or polyhedral scatterers of mixed type Technical Report 2006-03(337) The Chinese University of Hong Kong) and addresses the unique determination of partially coated polyhedral scatterers in {\\bb R}^N (N >= 2) along with their surface impedance from far field data. Two global uniqueness results are established for this inverse problem with a scatterer consisting of multiple solid polyhedra: the first one is to determine such a scatterer of mixed sound-soft and impedance type by a single incident plane wave and the other is to determine such a scatterer of mixed sound-soft, sound-hard and impedance type by N different incident waves in the N-dimensional case with N >= 3 and by only one incident wave for the two-dimensional case. Then we present some examples to show that as long as a scatterer admits the presence of (sound-hard) crack-type obstacles, then one cannot determine the scatterer uniquely by any less than N different incident plane waves. These examples also reveal that the uniqueness results achieved earlier in [15, 16] for polyhedral scatterers are optimal. Finally, the uniqueness results that have been solved or are still unsolved for the polyhedral-type scatterers with both solid and crack components are summarized in the conclusion.

  3. Filling-in by joint interpolation of vector fields and gray levels.

    PubMed

    Ballester, C; Bertalmio, M; Caselles, V; Sapiro, G; Verdera, J

    2001-01-01

    A variational approach for filling-in regions of missing data in digital images is introduced. The approach is based on joint interpolation of the image gray levels and gradient/isophotes directions, smoothly extending in an automatic fashion the isophote lines into the holes of missing data. This interpolation is computed by solving the variational problem via its gradient descent flow, which leads to a set of coupled second order partial differential equations, one for the gray-levels and one for the gradient orientations. The process underlying this approach can be considered as an interpretation of the Gestaltist's principle of good continuation. No limitations are imposed on the topology of the holes, and all regions of missing data can be simultaneously processed, even if they are surrounded by completely different structures. Applications of this technique include the restoration of old photographs and removal of superimposed text like dates, subtitles, or publicity. Examples of these applications are given. We conclude the paper with a number of theoretical results on the proposed variational approach and its corresponding gradient descent flow. PMID:18255537

  4. Joint swelling

    MedlinePlus

    Swelling of a joint ... Joint swelling may occur along with joint pain . The swelling may cause the joint to appear larger or abnormally shaped. Joint swelling can cause pain or stiffness. After an ...

  5. The 1995 revision of the joint US/UK geomagnetic field models - I. Secular variation

    USGS Publications Warehouse

    Macmillan, S.; Barraclough, D.R.; Quinn, J.M.; Coleman, R.J.

    1997-01-01

    We present the methods used to derive mathematical models of global secular variation of the main geomagnetic field for the period 1985 to 2000. These secular-variation models are used in the construction of the candidate US/UK models for the Definitive Geomagnetic Reference Field at 1990, the International Geomagnetic Reference Field for 1995 to 2000, and the World Magnetic Model for 1995 to 2000 (see paper II, Quinn et al., 1997). The main sources of data for the secular-variation models are geomagnetic observatories and repeat stations. Over the areas devoid of these data secular-variation information is extracted from aeromagnetic and satellite data. We describe how secular variation is predicted up to the year 2000 at the observatories and repeat stations, how the aeromagnetic and satellite data are used, and how all the data are combined to produce the required models.

  6. Momentum and Turbulent Kinetic Energy Budgets Within the Park Avenue Street Canyon During the Joint Urban 2003 Field Campaign

    NASA Astrophysics Data System (ADS)

    Nelson, Matthew A.; Pardyjak, Eric R.; Klein, Petra

    2011-07-01

    Very few attempts have so far been made to quantify the momentum and turbulent kinetic energy (TKE) budgets within real urban canopies. In this study, sonic anemometer data obtained during the Joint Urban 2003 field campaign in Oklahoma City, U.S.A. were used for calculating the momentum and TKE budgets within a real-world urban street canyon. Sonic anemometers were deployed on multiple towers in the lower half of the canyon. Gradients in all three principal directions were included in the analyses. The storage and buoyancy terms were found to have negligible contributions to both the momentum and TKE budgets. The momentum budgets were generally found to be more complex than a simple balance of two physical processes. The horizontal terms were found to have significant and sometimes dominant contributions to the momentum and TKE budgets.

  7. Accuracy of low-field magnetic resonance imaging versus radiography for guiding injection of equine distal interphalangeal joint collateral ligaments.

    PubMed

    Lamb, Megan M; Barrett, Jennifer G; White, Nathaniel A; Werre, Stephen R

    2014-01-01

    Desmopathy of the distal interphalangeal joint collateral ligament is a common cause of lameness in the horse and carries a variable prognosis for soundness. Intralesional treatment has been proposed for improving outcome; however, limited reports describe methods for injecting this ligament. The purpose of this study was to compare accuracy of low-field magnetic resonance imaging (MRI) vs. radiography for injecting the collateral ligament of the distal interphalangeal joint. Equine cadaver digit pairs (n = 10) were divided by random assignment to injection of the ligament by either technique. An observer unaware of injection technique determined injection success based on postinjection MRI and/or gross sections acquired from the proximal, middle, and distal portions of the ligament. McNemar's test was performed to determine statistical difference between injection techniques, the number of injection attempts, and injection of the medial or lateral collateral ligament. Magnetic resonance imaging guided injection was successful more frequently than radiographic-guided injection based on postinjection MRI (24 of 30 vs. 9 of 30; P = 0.0006) and gross sections (26 of 30 vs. 13 of 30; P = 0.0008). At each level of the ligament (proximal, middle, and distal), MRI-guided injection resulted in more successful injections than radiographic guidance. Statistical significance occurred at the proximal aspect of the collateral ligament based on postinjection MRI (P = 0.0143) and the middle portion of the ligament based on gross sections (P = 0.0253). Findings supported future testing of standing, low-field MRI as a technique for delivering intralesional regenerative therapy in live horses with desmopathy of these collateral ligaments. PMID:24102665

  8. Joint use of laboratory bioassays and field-collected plants to evaluate toxicity and contaminant bioaccumulation

    SciTech Connect

    Long, S.P.; Byron, E.R.; Ohlendorf, H.M.

    1995-12-31

    Soil toxicity tests using lettuce (Latuca saliva) were conducted using soil samples collected as part of ecological risk assessments at two facilities in California. At some sites, terrestrial plants were collected in the field for chemical analysis. Ecological concerns focused on exposures to plants, phytophagous insects, and their secondary consumers, such as birds and small mammals. The toxicity tests were used to assess potential exposures to a variety of site-specific contaminants including organochlorine pesticides, PCBs, PAHs, petroleum hydrocarbons, heavy metals, and other inorganic substances. Site soils were combined with clean control soils to produce toxicity test soil dilutions containing 100%, 75%, 50%, 25%, and 0% site soils. Observations of seed germination and growth were made at day 0, 7, 14, 21 and 28. Toxicity test results were combined with soil chemical analytical results and physical characteristics to establish NOAELs and LOAELs. Bioaccumulation in the lettuce and field-collected plants was evaluated by comparing plant contaminant to soil contaminant concentrations. Allometric equations and sublethal toxicity data were used to predict potential effects on birds and small mammals. Whole-body contaminant concentrations in insects collected on some of the plants in the field were also considered in evaluating the potential for toxicity to insectivorous birds. The study indicated that contaminant uptake was occurring in the field-collected and bioassay plants but not the insects. Site factors in addition to soil contaminant concentration influenced the potential for plant toxicity and bioaccumulation.

  9. A comparison of iron oxide-rich joint coatings and rock chips as geochemical sampling media in exploration for disseminated gold deposits

    USGS Publications Warehouse

    Crone, W.; Larson, L.T.; Carpenter, R.H.; Chao, T.T.; Sanzolone, R.F.

    1984-01-01

    We evaluated the effectiveness of iron oxide-rich fracture coatings as a geochemical sampling medium for disseminated gold deposits, as compared with conventional lithogeochemical methods, for samples from the Pinson mine and Preble prospect in southeastern Humboldt County, Nevada. That disseminated gold mineralization is associated with Hg, As, and Sb is clearly demonstrated in these deposits for both fracture coatings and rock chip samples. However, the relationship is more pronounced for fracture coatings. Fracture coatings at Pinson contain an average of 3.61, 5.13, 14.37, and 3.42 times more Au, As, Sb and Hg, respectively, than adjacent rock samples. At Preble, fracture coatings contain 3.13, 9.72, 9.18, and 1.85 times more Au, As, Sb and Hg, respectively, than do adjacent rock samples. Geochemical anomalies determined from fracture coatings are thus typically more intense than those determined from rock samples for these elements. The sizes of anomalies indicated by fracture coatings are also somewhat larger, but this is less obvious. In both areas, Sb anomalies are more extensive in fracture coatings. At Preble, some Hg and Au anomalies are also more extensive in fracture coatings. In addition to halos formed by the Hg, As and Sb, high values for Au/Ag and Zn/(Fe + Mn) are closely associated with gold mineralization at the Pinson mine. The large enhancement in geochemical response afforded by fracture coatings indicates a definite potential in the search for buried disseminated gold deposits. ?? 1984.

  10. Estimation of field-scale soil hydraulic and dielectric parametersthrough joint inversion of GPR and hydrological data

    SciTech Connect

    Kowalsky, Michael B.; Finsterle, Stefan; Peterson, John; Hubbard,Susan; Rubin, Yoram; Majer, Ernest; Ward, Andy; Gee, Glendon

    2005-05-05

    A method is described for jointly using time-lapse multiple-offset cross-borehole ground-penetrating radar (GPR) travel time measurements and hydrological measurements to estimate field-scale soil hydraulic parameters and parameters of the petrophysical function, which relates soil porosity and water saturation to the effective dielectric constant. We build upon previous work to take advantage of a wide range of GPR data acquisition configurations and to accommodate uncertainty in the petrophysical function. Within the context of water injection experiments in the vadose zone, we test our inversion methodology with synthetic examples and apply it to field data. The synthetic examples show that while realistic errors in the petrophysical function cause substantial errors in the soil hydraulic parameter estimates,simultaneously estimating petrophysical parameters allows for these errors to be minimized. Additionally, we observe in some cases that inaccuracy in the GPR simulator causes systematic error in simulated travel times, making necessary the simultaneous estimation of a correction parameter. We also apply the method to a three-dimensional field setting using time-lapse GPR and neutron probe (NP) data sets collected during an infiltration experiment at the U.S. Department of Energy (DOE) Hanford site in Washington. We find that inclusion of GPR data in the inversion procedure allows for improved predictions of water content, compared to predictions made using NP data alone.

  11. Dual-coated lactic acid bacteria: an emerging innovative technology in the field of probiotics.

    PubMed

    Alvarez-Calatayud, Guillermo; Margolles, Abelardo

    2016-01-01

    Probiotics are living micro-organisms that do not naturally have shelf life, and normally are weakly protected against the digestive action of the GI tract. A new dual coating technology has been developed in an effort to maximize survival, that is, to be able to reach the intestine alive and in sufficient numbers to confer the beneficial health effects on the host. Dual-coating of lactic acid bacteria (LAB) is the result of fourth-generation coating technology for the protection of these bacteria at least 100-fold or greater than the uncoated LAB. This innovative technique involves a first pH-dependent protein layer that protects bacteria from gastric acid and bile salt, and a second polysaccharide matrix that protects bacteria from external factors, such as humidity, temperature and pressure, as well as the digestive action during the passage through the GI tract. Dual-coated probiotic formulation is applicable to different therapeutic areas, including irritable bowel syndrome, atopic dermatitis, acute diarrhea, chronic constipation, Helicobacter pylori eradication, and prevention of antibiotic-associated diarrhea. An updated review of the efficacy of doubly coated probiotic strains for improving bacterial survival in the intestinal tract and its consequent clinical benefits in humans is here presented. PMID:26780116

  12. Research of Arc Chamber Optimization Techniques Based on Flow Field and Arc Joint Simulation

    NASA Astrophysics Data System (ADS)

    Zhong, Jianying; Guo, Yujing; Zhang, Hao

    2016-03-01

    The preliminary design of an arc chamber in the 550 kV SF6 circuit breaker was proposed in accordance with the technical requirements and design experience. The structural optimization was carried out according to the no-load flow field simulation results and verified by no-load pressure measurement. Based on load simulation results such as temperature field variation at the arc area and the tendency of post arc current under different recovery voltage, the second optimal design was completed and its correctness was certificated by a breaking test. Results demonstrate that the interrupting capacity of an arc chamber can be evaluated by the comparison of the gas medium recovery speed and post arc current growth rate.

  13. Joint Offshore Wind Field Monitoring with Spaceborne SAR and Platform-Based Doppler LIDAR Measurements

    NASA Astrophysics Data System (ADS)

    Jacobsen, S.; Lehner, S.; Hieronimus, J.; Schneemann, J.; Kuhn, M.

    2015-04-01

    The increasing demand for renewable energy resources has promoted the construction of offshore wind farms e.g. in the North Sea. While the wind farm layout consists of an array of large turbines, the interrelation of wind turbine wakes with the remaining array is of substantial interest. The downstream spatial evolution of turbulent wind turbine wakes is very complex and depends on manifold parameters such as wind speed, wind direction and ambient atmospheric stability conditions. To complement and validate existing numerical models, corresponding observations are needed. While in-situ measurements with e.g. anemometers provide a time-series at the given location, the merits of ground-based and space- or airborne remote sensing techniques are indisputable in terms of spatial coverage. Active microwave devices, such as Scatterometer and Synthetic Aperture Radar (SAR), have proven their capabilities of providing sea surface wind measurements and particularly SAR images reveal wind variations at a high spatial resolution while retaining the large coverage area. Platform-based Doppler LiDAR can resolve wind fields with a high spatial coverage and repetition rates of seconds to minutes. In order to study the capabilities of both methods for the investigation of small scale wind field structures, we present a direct comparison of observations obtained by high resolution TerraSAR-X (TS-X) X-band SAR data and platform-based LiDAR devices at the North Sea wind farm alpha ventus. We furthermore compare the results with meteorological data from the COSMO-DE model run by the German Weather Service DWD. Our study indicates that the overall agreement between SAR and LiDAR wind fields is good and that under appropriate conditions small scale wind field variations compare significantly well.

  14. Joint Application of TDR, GPR and Inverse Hydraulic Modeling to Infer Field Scale Hydraulic Properties

    NASA Astrophysics Data System (ADS)

    Wollschläger, U.; Gerhards, H.; Schneider, S.; Roth, K.

    2007-12-01

    Estimating field scale hydraulic properties is still a challenge in hydrology. Most classical methods require undisturbed soil samples that have to be excavated during time consuming and labour intensive field work which is often followed by tedious measurements of hydraulic properties in the laboratory. Since these methods can only be applied with a limited number of samples, often only a few point measurements need to be used to characterize field scale hydraulic properties while layer geometry has to be derived from interpolation of these values and additional drilling. The combination of geophysical measurement techniques and hydraulic modeling offers an attractive alternative to bridge the gap between i) few accurate point measurements that are used to infer local hydraulic properties and ii) spatial mapping of the respective layers over large scales. We use a time series of water contents measured in a soil profile with time domain reflectometry to estimate hydraulic properties of the different soil layers with a 1D hydraulic inverse model. Here, hydraulic properties are estimated from \\it in situ \

  15. Formation of tough composite joints

    SciTech Connect

    Brun, M.K.

    1997-05-01

    Joints which exhibit tough fracture behavior were formed in a composite with a Si/SiC matrix reinforced with Textron SCS-6 fibers with either boron nitride or silicon nitride fiber coatings. In composites with BN coatings fibers were aligned uniaxially, while composites with Si{sub 3}N{sub 4}-coated fibers had a 0/90{degree} architecture. Lapped joints (joints with overlapping fingers) were necessary to obtain tough behavior. Geometrical requirements necessary to avoid brittle joint failure have been proposed. Joints with a simple overlap geometry (only a few fingers) would have to be very long in order to prevent brittle failure. Typical failure in these joints is caused by a crack propagating along the interfaces between the joint fingers. Joints of the same overall length, but with geometry changed to be symmetric about the joint centerline and with an extra shear surface exhibited tough fractures accompanied with extensive fiber pullout. The initial matrix cracking of these joints was relatively low because cracks propagated easily through the ends of the fingers. Joints with an optimized stepped sawtooth geometry produced composite-like failures with the stress/strain curves containing an elastic region followed by a region of rising stress with an increase of strain. Increasing the fiber/matrix interfacial strength from 9 to 25 MPa, by changing the fiber coating, increased matrix cracking and ultimate strength of the composite significantly. The best joints had matrix cracking stress and ultimate strength of 138 and 240 MPa, respectively. Joint failure was preceded by multiple matrix cracking in the entire composite. The high strength of the joints will permit building of structures containing joints with only a minor reduction of design stresses.

  16. Complex frequencies and field distributions of localized surface plasmon modes in graphene-coated subwavelength wires

    NASA Astrophysics Data System (ADS)

    Cuevas, Mauro; Riso, Máximo A.; Depine, Ricardo A.

    2016-04-01

    In this work we study the modal characteristics of localized surface plasmons in graphene-coated, circular cross-section wires. Localized surface plasmons are represented in terms of cylindrical multipole partial waves characterized by discrete, complex frequencies that depend on the size of the wire and can be dynamically tuned via a gate voltage. We consider both intrinsically nonplasmonic wires and intrinsically plasmonic wires. In the first case the localized surface plasmons are introduced by the graphene coating, whereas in the second case the localized eigenmodes of the graphene coating are expected to hybridize those already existing in the bare wire. We show that the approach presented here, valid for particle sizes where the retardation effects can be significant, is in good agreement with analytical expressions obtained in the limit when particle size is very small compared to the wavelength of the eigenmode and with results indirectly determined from scattering cross-section spectra.

  17. Micellar-polymer joint demonstration project, Wilmington Field, California. Third annual report, June 1978-July 1979

    SciTech Connect

    Staub, H.L.

    1981-08-01

    The micellar-polymer demonstration project to be conducted - through the design phase - in the HXa sand of Wilmington Field is proceeding satisfactorily but has fallen behind schedule. Results of some core floods were unsatisfactory. The recovery efficiencies were much lower than those achieved using the laboratory sample cosurfactant final design slug. Nearly six months of reformulating and additional core testing were required to finally achieve satisfactory laboratory results. Other laboratory tests were performed to optimize the polymer buffer for size and concentration. Other reservoir and reservoir fluid problems have been encountered in production and injection operations during the pre-flush period.

  18. Development of the cryo-rotary joint for a HTS synchronous motor with Gd-bulk HTS field-pole magnets

    NASA Astrophysics Data System (ADS)

    Miki, M.; Felder, B.; Tsuzuki, K.; Izumi, M.; Hayakawa, H.

    2010-06-01

    We have studied a prototype of an axial-gap type synchronous motor with Gd-bulk HTS field-pole magnets since 2001. At the liquid nitrogen temperature, these bulks have trapped over 1 T inside the motor after being applied the pulsed field magnetization method. Increasing the flux of the field poles is the most straightforward way of improving the output power of the motor. Cooling down the bulk HTS magnets below the liquid nitrogen temperature provides an effective alternative to increase the magnetic flux trapping. In 2007, we exchanged the cryogen from liquid nitrogen to condensed neon. The key technology of this challenge is a rotary joint, introducing a fluid cryogen into the rotating body in the motor from the static reservoir. We have successfully developed a compact rotary joint which is smaller and lighter than the existent one (1/10 volume, 1/3 length and 1/12 weight). The present joint was manufactured and evaluated with liquid nitrogen and condensed neon. We presume a total heat loss of this rotary joint of less than 10 watts. Successful cooling and rotating tests of the bulk-HTS motor with this novel rotary joint are conducted.

  19. Joint use of laboratory bioassays and field-collected invertebrates to evaluate toxicity and contaminant bioaccumulation

    SciTech Connect

    Long, S.P.; Byron, E.R.; Ohlendorf, H.M.

    1995-12-31

    Soil toxicity tests using earthworms (Eisenia andrei) were conducted using soil samples collected as part of ecological risk assessments for several sites at two facilities in California. At some sites, earthworms or other terrestrial invertebrates were collected in the field for chemical analysis. Ecological concerns focused on exposures to soil invertebrates and their secondary consumers, such as birds and small mammals. The toxicity tests were used to assess potential exposures to a variety of site-specific contaminants including organochlorine pesticides, PCBs, PAHs, petroleum hydrocarbons, heavy metals, and other inorganic substances. Site soils were combined with clean control soils to produce toxicity test soil dilutions containing 100%, 75%, 50%, 25%, and 0% site soils. Earthworm mortality and other observations were made at day 0, 7, 14, 21 and 28. Toxicity test results were combined with soil chemical analytical results and physical characteristics to establish NOAELs and LOAELs. Bioaccumulation in the laboratory earthworms and field-collected invertebrates was evaluated by comparing whole-body contaminant to soil contaminant concentrations. Allometric equations and sublethal toxicity data were used to predict potential effects on birds and small mammals. Earthworm toxicity tests indicated a wide range of sensitivity to on-site contaminants and showed the importance of considering potential confounding influences due to soil parameters other than contaminant concentration.

  20. A joint geophysical analysis of the Coso geothermal field, south-eastern California

    NASA Astrophysics Data System (ADS)

    Wamalwa, Antony M.; Mickus, Kevin L.; Serpa, Laura F.; Doser, Diane I.

    2013-01-01

    Three-dimensional density models derived from gravity data and two-dimensional resistivity models derived from magnetotelluric data collected in the vicinity of the Coso geothermal field are analyzed in order to determine the source region of the geothermal field. The derived models show zones of both low resistivity and low density at and below 6 km depth in the Devils Kitchen and the Coso Hot Springs areas. These zones agree with seismic reflection and tomography results which found a high amplitude reflector at 5 km and low velocities zones below 5 km. We interpret the density and resistivity zones to indicate the presence of cooling magmatic material that provides the heat for the shallower geothermal system in these regions. A zone marked by high resistivity and low density was found to lie directly above the interpreted partially melted region extending to within 1 km depth below the surface in the reservoir region where it is capped by a low resistivity clay zone. In addition, the density models indicate that the high density bodies occurring under volcanic outcrops may be mafic intrusions.

  1. THE APOKASC CATALOG: AN ASTEROSEISMIC AND SPECTROSCOPIC JOINT SURVEY OF TARGETS IN THE KEPLER FIELDS

    SciTech Connect

    Pinsonneault, Marc H.; Epstein, Courtney; Johnson, Jennifer A.; Elsworth, Yvonne; Chaplin, William J.; Hekker, Saskia; Silva Aguirre, Victor; Stello, Dennis; Mészáros, Sz.; García, Rafael A.; Beck, Paul; Mathur, Savita; García Pérez, Ana; Girardi, Léo; Basu, Sarbani; Shetrone, Matthew; Allende Prieto, Carlos; Beers, Timothy C.; and others

    2015-01-01

    We present the first APOKASC catalog of spectroscopic and asteroseismic properties of 1916 red giants observed in the Kepler fields. The spectroscopic parameters provided from the Apache Point Observatory Galactic Evolution Experiment project are complemented with asteroseismic surface gravities, masses, radii, and mean densities determined by members of the Kepler Asteroseismology Science Consortium. We assess both random and systematic sources of error and include a discussion of sample selection for giants in the Kepler fields. Total uncertainties in the main catalog properties are of the order of 80 K in T {sub eff}, 0.06 dex in [M/H], 0.014 dex in log g, and 12% and 5% in mass and radius, respectively; these reflect a combination of systematic and random errors. Asteroseismic surface gravities are substantially more precise and accurate than spectroscopic ones, and we find good agreement between their mean values and the calibrated spectroscopic surface gravities. There are, however, systematic underlying trends with T {sub eff} and log g. Our effective temperature scale is between 0 and 200 K cooler than that expected from the infrared flux method, depending on the adopted extinction map, which provides evidence for a lower value on average than that inferred for the Kepler Input Catalog (KIC). We find a reasonable correspondence between the photometric KIC and spectroscopic APOKASC metallicity scales, with increased dispersion in KIC metallicities as the absolute metal abundance decreases, and offsets in T {sub eff} and log g consistent with those derived in the literature. We present mean fitting relations between APOKASC and KIC observables and discuss future prospects, strengths, and limitations of the catalog data.

  2. The APOKASC Catalog: An Asteroseismic and Spectroscopic Joint Survey of Targets in the Kepler Fields

    NASA Astrophysics Data System (ADS)

    Pinsonneault, Marc H.; Elsworth, Yvonne; Epstein, Courtney; Hekker, Saskia; Mészáros, Sz.; Chaplin, William J.; Johnson, Jennifer A.; García, Rafael A.; Holtzman, Jon; Mathur, Savita; García Pérez, Ana; Silva Aguirre, Victor; Girardi, Léo; Basu, Sarbani; Shetrone, Matthew; Stello, Dennis; Allende Prieto, Carlos; An, Deokkeun; Beck, Paul; Beers, Timothy C.; Bizyaev, Dmitry; Bloemen, Steven; Bovy, Jo; Cunha, Katia; De Ridder, Joris; Frinchaboy, Peter M.; García-Hernández, D. A.; Gilliland, Ronald; Harding, Paul; Hearty, Fred R.; Huber, Daniel; Ivans, Inese; Kallinger, Thomas; Majewski, Steven R.; Metcalfe, Travis S.; Miglio, Andrea; Mosser, Benoit; Muna, Demitri; Nidever, David L.; Schneider, Donald P.; Serenelli, Aldo; Smith, Verne V.; Tayar, Jamie; Zamora, Olga; Zasowski, Gail

    2014-12-01

    We present the first APOKASC catalog of spectroscopic and asteroseismic properties of 1916 red giants observed in the Kepler fields. The spectroscopic parameters provided from the Apache Point Observatory Galactic Evolution Experiment project are complemented with asteroseismic surface gravities, masses, radii, and mean densities determined by members of the Kepler Asteroseismology Science Consortium. We assess both random and systematic sources of error and include a discussion of sample selection for giants in the Kepler fields. Total uncertainties in the main catalog properties are of the order of 80 K in T eff, 0.06 dex in [M/H], 0.014 dex in log g, and 12% and 5% in mass and radius, respectively; these reflect a combination of systematic and random errors. Asteroseismic surface gravities are substantially more precise and accurate than spectroscopic ones, and we find good agreement between their mean values and the calibrated spectroscopic surface gravities. There are, however, systematic underlying trends with T eff and log g. Our effective temperature scale is between 0 and 200 K cooler than that expected from the infrared flux method, depending on the adopted extinction map, which provides evidence for a lower value on average than that inferred for the Kepler Input Catalog (KIC). We find a reasonable correspondence between the photometric KIC and spectroscopic APOKASC metallicity scales, with increased dispersion in KIC metallicities as the absolute metal abundance decreases, and offsets in T eff and log g consistent with those derived in the literature. We present mean fitting relations between APOKASC and KIC observables and discuss future prospects, strengths, and limitations of the catalog data.

  3. Influence of the flow field in curtain coating onto a prewet substrate

    NASA Astrophysics Data System (ADS)

    Marston, J. O.; Simmons, M. J. H.; Decent, S. P.; Kirk, S. P.

    2006-11-01

    The onset of air entrainment for curtain coating onto a surface prewetted with the coating fluid was studied. The substrate used was a polished, scraped steel wheel and coating was performed over ranges of dimensionless parameters observed in commercial coating processes (Reynolds number, 0.14coating is possible at higher substrate velocities than would be predicted by conventional theory. This "intense assist" exhibits a complex relationship with the prewet film thickness. The results presented in this paper demonstrate that hydrodynamic assist is not exclusive to wetting, but is a generic phenomenon of fluid flows.

  4. High mobility organic field-effect transistor based on water-soluble deoxyribonucleic acid via spray coating

    SciTech Connect

    Shi, Wei; Han, Shijiao; Huang, Wei; Yu, Junsheng

    2015-01-26

    High mobility organic field-effect transistors (OFETs) by inserting water-soluble deoxyribonucleic acid (DNA) buffer layer between electrodes and pentacene film through spray coating process were fabricated. Compared with the OFETs incorporated with DNA in the conventional organic solvents of ethanol and methanol: water mixture, the water-soluble DNA based OFET exhibited an over four folds enhancement of field-effect mobility from 0.035 to 0.153 cm{sup 2}/Vs. By characterizing the surface morphology and the crystalline structure of pentacene active layer through atomic force microscope and X-ray diffraction, it was found that the adoption of water solvent in DNA solution, which played a key role in enhancing the field-effect mobility, was ascribed to both the elimination of the irreversible organic solvent-induced bulk-like phase transition of pentacene film and the diminution of a majority of charge trapping at interfaces in OFETs.

  5. Sensorimotor Results From a Joint NASA and Russian Pilot Field Test

    NASA Technical Reports Server (NTRS)

    Reschke, Millard F.; Kozlovskaya, Inessa B.

    2016-01-01

    Assessing the full impact of sensorimotor decrements associated with long-duration spaceflight has not been undertaken until 24 hours after landing. To overcome this limitation, both the Russian and U.S. space programs have implemented crew testing at the Soyuz landing site with additional follow-up measurements within 24 hours. Identified as the Pilot Field Test (PFT) this research on NASA’s side included: (1) a sit-to-stand test, (2) recovery from a simulated fall stand test where the crewmember begins in the prone position and then stands for 3.5 minutes while cardiovascular and postural ataxia data are acquired, and (3) a tandem heel-to-toe walk. Video, cardiovascular parameters (heart rate and blood pressure), data from body-worn inertial sensors, and severity of postflight motion sickness were collected during each test session. Russian investigators made measurements associated with: (a) obstacle avoidance, (b) muscle compliance, (c) postural adjustments to perturbations (pushes) applied to the subject’s chest area and (d) center of mass measurements made across most test objectives with insoles inserted into the subjects’ shoes. Data from 18 subjects have been obtained. Additional measurements on functional tests are now being obtained. The increased level of functional deficits not attributable to strength observed in crewmembers has been substantially greater than previously observed when compared with measurements obtained after 24 hours. Full recovery requires 6 to 16 days. Measureable performance parameters such as those associated with functional behaviors are required to provide an evidence base for characterizing programmatic risks for undertaking exploration missions where crewmembers will be unassisted after landing.

  6. Invariant joint distribution of a stationary random field and its derivatives: Euler characteristic and critical point counts in 2 and 3D

    SciTech Connect

    Pogosyan, Dmitry; Gay, Christophe; Pichon, Christophe

    2009-10-15

    The full moments expansion of the joint probability distribution of an isotropic random field, its gradient, and invariants of the Hessian are presented in 2 and 3D. It allows for explicit expression for the Euler characteristic in ND and computation of extrema counts as functions of the excursion set threshold and the spectral parameter, as illustrated on model examples.

  7. Insert coil test for HEP high field magnets using yba2cu3o7-δ coated conductor tapes

    NASA Astrophysics Data System (ADS)

    Lombardo, Vito; Barzi, Emanuela; Turrioni, Daniele; Zlobin, Alexander

    2012-06-01

    The final beam cooling stages of a Muon Collider require DC solenoid magnets with magnetic fields of 30-50 T. In this paper we present progress in insert coil development using commercially available YBa2Cu3O7.δ Coated Conductor. Technological aspects covered in the development, including coil geometry, insulation, manufacturing process and testing are summarized and discussed. Test results of double pancake coils operated in liquid nitrogen and liquid helium are presented and compared with the performance of YBa2Cu3O7.δ tape short samples.

  8. Multifunctional coatings to simultaneously promote osseointegration and prevent infection of orthopaedic implants.

    PubMed

    Raphel, Jordan; Holodniy, Mark; Goodman, Stuart B; Heilshorn, Sarah C

    2016-04-01

    The two leading causes of failure for joint arthroplasty prostheses are aseptic loosening and periprosthetic joint infection. With the number of primary and revision joint replacement surgeries on the rise, strategies to mitigate these failure modes have become increasingly important. Much of the recent work in this field has focused on the design of coatings either to prevent infection while ignoring bone mineralization or vice versa, to promote osseointegration while ignoring microbial susceptibility. However, both coating functions are required to achieve long-term success of the implant; therefore, these two modalities must be evaluated in parallel during the development of new orthopaedic coating strategies. In this review, we discuss recent progress and future directions for the design of multifunctional orthopaedic coatings that can inhibit microbial cells while still promoting osseointegration. PMID:26851394

  9. Joint inversion of teleseismic, geodetic, and near-field waveform datasets for rupture process of the 2015 Gorkha, Nepal, earthquake

    NASA Astrophysics Data System (ADS)

    Kobayashi, Hiroaki; Koketsu, Kazuki; Miyake, Hiroe; Takai, Nobuo; Shigefuji, Michiko; Bhattarai, Mukunda; Sapkota, Soma Nath

    2016-04-01

    The 2015 Gorkha earthquake and its aftershocks caused severe damage mostly in Nepal, while countries around the Himalayan region were warned for decades about large Himalayan earthquakes and the seismic vulnerability of these countries. However, the magnitude of the Gorkha earthquake was smaller than those of historical earthquakes in Nepal, and the most severe damage occurred in the north and northeast of Kathmandu. We explore reasons for these unexpected features by performing a joint source inversion of teleseismic, geodetic, and near-field waveform datasets to investigate the rupture process. Results indicate that the source fault was limited to the northern part of central Nepal and did not reach the Main Frontal Thrust. The zone of large slip was located in the north of Kathmandu, and the fault rupture propagated eastward with an almost constant velocity. Changes in the Coulomb failure function (ΔCFF) due to the Gorkha earthquake were computed, indicating that southern and western regions neighboring the source fault are potential source regions for future earthquakes related to the Gorkha earthquake. These two regions may correspond to the historical earthquakes of 1866 and 1344. Possible future earthquakes in the regions are predicted, and the warning for Himalayan seismic hazards remains high even after the Gorkha earthquake.

  10. Easy-to-clean property and durability of superhydrophobic flaky γ-alumina coating on stainless steel in field test at a paper machine

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaoxue; Liu, Xuwen; Laakso, Jarmo; Levänen, Erkki; Mäntylä, Tapio

    2012-01-01

    Superhydrophobic flaky γ-alumina coating was prepared on AISI 316 2B stainless steel and was field-tested near size roll at a paper machine in a paper mill for 6 weeks consisting of two running periods of machine to check the easy-to-clean property and durability, as compared to an uncoated reference stainless steel. In the end of the field test, both the superhydrophobic and the reference stainless steel were fully covered with substances from the testing environment. Major part of the collected substances on the superhydrophobic stainless steel can be washed away by pressurized water; however, the collected substances remained on the reference stainless steel after washing. The field-tested samples were characterized visually and by stereomicroscopy, field emission scanning electron microscopy, laser profilometry and contact angle tester. The field test revealed the easy-to-clean property of the superhydrophobic surface and the superhydrophobic coating survived rather well after the first running period of 16 days in the field test. The resistance and durability of the superhydrophobic surface still needs to be further improved for longer term application in paper industry. Nanoindentation was used to further study the mechanical properties of the γ-alumina coating. It was found that the γ-alumina coating became much softer after transforming from flat to flaky form. In addition, the flaky γ-alumina coating demonstrated a phenomenon of time-dependent plasticity and some flexibility.