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Sample records for anode sheath switching

  1. Experimental Studies of Anode Sheath Phenomena in a Hall Thruster Discharge

    International Nuclear Information System (INIS)

    Dorf, L.; Raitses, Y.; Fisch, N.J.

    2004-01-01

    Both electron-repelling and electron-attracting anode sheaths in a Hall thruster were characterized by measuring the plasma potential with biased and emissive probes [L. Dorf, Y. Raitses, V. Semenov, and N.J. Fisch, Appl. Phys. Let. 84 (2004) 1070]. In the present work, two-dimensional structures of the plasma potential, electron temperature, and plasma density in the near-anode region of a Hall thruster with clean and dielectrically coated anodes are identified. Possible mechanisms of anode sheath formation in a Hall thruster are analyzed. The path for current closure to the anode appears to be the determining factor in the anode sheath formation process. The main conclusion of this work is that the anode sheath formation in Hall thrusters differs essentially from that in the other gas discharge devices, like a glow discharge or a hollow anode, because the Hall thruster utilizes long electron residence times to ionize rather than high neutral pressures

  2. Individual Zn2SnO4-sheathed ZnO heterostructure nanowires for efficient resistive switching memory controlled by interface states.

    Science.gov (United States)

    Cheng, Baochang; Ouyang, Zhiyong; Chen, Chuan; Xiao, Yanhe; Lei, Shuijin

    2013-11-19

    Resistive switching (RS) devices are widely believed as a promising candidate for next generation nonvolatile resistance random access memory. Here, Zn2SnO4-sheathed ZnO core/shell heterostructure nanowires were constructed through a polymeric sol-gel approach followed by post-annealing. The back-to-back bipolar RS properties were observed in the Ohmic contact two-terminal devices based on individual core/shell nanowires. With increasing bias to about 1.5 V, it changes from high-resistance states (HRS) to low-resistance states, and however, it can be restored to HRS by reverse bias. We propose a new mechanism, which is attributed to the injection of electrons into/from interfacial states, arising from the lattice mismatch at ZnO/Zn2SnO4 heterointerface. Upon applying negative/positive voltage at one end of devices, where interfacial states are filled/emptied, barrier will be eliminated/created, resulting into symmetric RS characteristics. The behavior of storage and removal charges demonstrates that the heterostructures have excellent properties for the application in resistance random access memory.

  3. Individual Zn2SnO4-sheathed ZnO heterostructure nanowires for efficient resistive switching memory controlled by interface states

    Science.gov (United States)

    Cheng, Baochang; Ouyang, Zhiyong; Chen, Chuan; Xiao, Yanhe; Lei, Shuijin

    2013-11-01

    Resistive switching (RS) devices are widely believed as a promising candidate for next generation nonvolatile resistance random access memory. Here, Zn2SnO4-sheathed ZnO core/shell heterostructure nanowires were constructed through a polymeric sol-gel approach followed by post-annealing. The back-to-back bipolar RS properties were observed in the Ohmic contact two-terminal devices based on individual core/shell nanowires. With increasing bias to about 1.5 V, it changes from high-resistance states (HRS) to low-resistance states, and however, it can be restored to HRS by reverse bias. We propose a new mechanism, which is attributed to the injection of electrons into/from interfacial states, arising from the lattice mismatch at ZnO/Zn2SnO4 heterointerface. Upon applying negative/positive voltage at one end of devices, where interfacial states are filled/emptied, barrier will be eliminated/created, resulting into symmetric RS characteristics. The behavior of storage and removal charges demonstrates that the heterostructures have excellent properties for the application in resistance random access memory.

  4. Anode Fall Formation in a Hall Thruster

    International Nuclear Information System (INIS)

    Dorf, Leonid A.; Raitses, Yevgeny F.; Smirnov, Artem N.; Fisch, Nathaniel J.

    2004-01-01

    As was reported in our previous work, accurate, nondisturbing near-anode measurements of the plasma density, electron temperature, and plasma potential performed with biased and emissive probes allowed the first experimental identification of both electron-repelling (negative anode fall) and electron-attracting (positive anode fall) anode sheaths in Hall thrusters. An interesting new phenomenon revealed by the probe measurements is that the anode fall changes from positive to negative upon removal of the dielectric coating, which appears on the anode surface during the course of Hall thruster operation. As reported in the present work, energy dispersion spectroscopy analysis of the chemical composition of the anode dielectric coating indicates that the coating layer consists essentially of an oxide of the anode material (stainless steel). However, it is still unclear how oxygen gets into the thruster channel. Most importantly, possible mechanisms of anode fall formation in a Hall thruster with a clean and a coated anodes are analyzed in this work; practical implication of understanding the general structure of the electron-attracting anode sheath in the case of a coated anode is also discussed

  5. Gap formation processes in a high-density plasma opening switch

    International Nuclear Information System (INIS)

    Grossmann, J.M.; Swanekamp, S.B.; Ottinger, P.F.; Commisso, R.J.; Hinshelwood, D.D.; Weber, B.V.

    1995-01-01

    A gap opening process in plasma opening switches (POS) is examined with the aid of numerical simulations. In these simulations, a high density (n e =10 14 --5x10 15 cm -3 ) uniform plasma initially bridges a small section of the coaxial transmission line of an inductive energy storage generator. A short section of vacuum transmission line connects the POS to a short circuit load. The results presented here extend previous simulations in the n e =10 12 --10 13 cm -3 density regime. The simulations show that a two-dimensional (2-D) sheath forms in the plasma near a cathode. This sheath is positively charged, and electrostatic sheath potentials that are large compared to the anode--cathode voltage develop. Initially, the 2-D sheath is located at the generator edge of the plasma. As ions are accelerated out of the sheath, it retains its original 2-D structure, but migrates axially toward the load creating a magnetically insulated gap in its wake. When the sheath reaches the load edge of the POS, the POS stops conducting current and the load current increases rapidly. At the end of the conduction phase a gap exists in the POS whose size is determined by the radial dimensions of the 2-D sheath. Simulations at various plasma densities and current levels show that the radial size of the gap scales roughly as B/n e , where B is the magnetic field. The results of this work are discussed in the context of long-conduction-time POS physics, but exhibit the same physical gap formation mechanisms as earlier lower density simulations more relevant to short-conduction-time POS. copyright 1995 American Institute of Physics

  6. Optic nerve sheath meningiomas

    NARCIS (Netherlands)

    Saeed, Peerooz; Rootman, Jack; Nugent, Robert A.; White, Valerie A.; Mackenzie, Ian R.; Koornneef, Leo

    2003-01-01

    To study the natural history and growth of optic nerve sheath meningiomas and evaluate their management outcome. Clinicopathologic retrospective noncomparative case series. A retrospective study of 88 patients who were treated between 1976 and 1999 at the University of British Columbia and the

  7. A radiation hard vacuum switch

    Science.gov (United States)

    Boettcher, G.E.

    1988-07-19

    A vacuum switch with an isolated trigger probe which is not directly connected to the switching electrodes. The vacuum switch within the plasmatron is triggered by plasma expansion initiated by the trigger probe which travels through an opening to reach the vacuum switch elements. The plasma arc created is directed by the opening to the space between the anode and cathode of the vacuum switch to cause conduction. 3 figs.

  8. Selective pH-Responsive Core-Sheath Nanofiber Membranes for Chem/Bio/Med Applications: Targeted Delivery of Functional Molecules.

    Science.gov (United States)

    Han, Daewoo; Steckl, Andrew J

    2017-12-13

    Core-sheath fibers using different Eudragit materials were successfully produced, and their controlled multi-pH responses have been demonstrated. Core-sheath fibers made of Eudragit L 100 (EL100) core and Eudragit S 100 (ES100) sheath provide protection and/or controlled release of core material at pH 6 by adjusting the sheath thickness (controlled by the flow rate of source polymer solution). The thickest sheath (∼250 nm) provides the least core release ∼1.25%/h, while the thinnest sheath (∼140 nm) provides much quicker release ∼16.75%/h. Furthermore, switching core and sheath material dramatically altered the pH response. Core-sheath fibers made of ES100 core and EL100 sheath can provide a consistent core release rate, while the sheath release rate becomes higher as the sheath layer becomes thinner. For example, the thinnest sheath (∼120 nm) provides a core and sheath release ratio of 1:2.5, while the thickest sheath (∼200 nm) shows only a ratio of 1:1.7. All core-sheath Eudragit fibers show no noticeable release at pH 5, while they are completely dissolved at pH 7. Extremely high surface area in the porous network of the fiber membranes provides much faster (>30 times) response to external pH changes as compared to that of equivalent cast films.

  9. Arc attachment at HID anodes: measurements and interpretation

    International Nuclear Information System (INIS)

    Redwitz, M; Dabringhausen, L; Lichtenberg, S; Langenscheidt, O; Heberlein, J; Mentel, J

    2006-01-01

    Anodes for high intensity discharge lamps made of cylindrical tungsten rods and the plasma in front of them are investigated in a special lamp filled with argon and other noble gases at pressures of 0.1-1 MPa. The arc attachment on these anodes takes place in a constricted mode. The temperature is measured pyrometrically along the electrode axis and the anode fall electrically. The electron temperature, T e , and the electron density, n e , within the anodic boundary layer are determined spectroscopically with high spatial resolution. It is found that the power input into the anode increases nearly linearly with the arc current. The proportionality constant is mainly determined by the work function of the electrode material and T e but is independent of the electrically measured anode fall and scarcely dependent on the electrode dimensions. The constriction is more pronounced in cold anodes, with maxima of T e and n e in front of the electrode surface, than on hot anodes with thermionic electron emission and vaporization of the electrode material. The distances of the T e - and n e -maxima from the anode surface are increased and T e is reduced in front of the anode with increasing anode temperature. The experimental findings may be explained by a model of the anodic boundary layer consisting of a thin sheath in front of the surface and a more extended constriction zone. The current and voltage are anti-parallel within the sheath. The power which is needed to sustain the sheath is supplied by an enhanced electrical power input into the constriction zone

  10. Anodic oxidation

    CERN Document Server

    Ross, Sidney D; Rudd, Eric J; Blomquist, Alfred T; Wasserman, Harry H

    2013-01-01

    Anodic Oxidation covers the application of the concept, principles, and methods of electrochemistry to organic reactions. This book is composed of two parts encompassing 12 chapters that consider the mechanism of anodic oxidation. Part I surveys the theory and methods of electrochemistry as applied to organic reactions. These parts also present the mathematical equations to describe the kinetics of electrode reactions using both polarographic and steady-state conditions. Part II examines the anodic oxidation of organic substrates by the functional group initially attacked. This part particular

  11. Central Mandibular Nerve Sheath Myxoma

    Directory of Open Access Journals (Sweden)

    Narges Ghazi

    2018-03-01

    Full Text Available Nerve sheath myxoma has been described as a rare neural tumor arising from Schwann cells. It is observed most frequently in the central area of the face, neck and upper extremities. In the past the term neurothekeoma was used as synonym for nerve sheath myxoma but according to new reports, they are separate entities which can be confirmed by immunohistochemistry as in our case. Oral involvement of this tumor is extremely rare. Here, we present an unusual case of nerve sheath myxoma in the mandible of a 22-year old female patient. This case appears to be the first myxomatous variant which is centrally located in the mandible.

  12. Sheath waves, non collisional dampings

    International Nuclear Information System (INIS)

    Marec, Jean Lucien Ernest

    1974-01-01

    When a metallic conductor is inserted into an ionised gas, an area of electron depletion is formed between the conductor and the plasma: the ionic sheath. Moreover, if the conductor is excited by an electric field, this ionic sheath plays an important role with respect to microwave properties. In this research thesis, the author addresses the range of frequencies smaller than the plasma frequency, and reports the study of resonance phenomena. After a presentation of the problem through a bibliographical study, the author recalls general characteristics of sheath wave propagation and of sheath resonances, and discusses the validity of different hypotheses (for example and among others, electrostatic approximations, cold plasma). Then, the author more particularly addresses theoretical problems related to non collisional dampings: brief bibliographical study, detailed presentation and description of the theoretical model, damping calculation methods. The author then justifies the design and performance of an experiment, indicates measurement methods used to determine plasma characteristics as well as other magnitudes which allow the description of mechanisms of propagation and damping of sheath waves. Experimental results are finally presented with respect to various parameters. The author discusses to which extent the chosen theoretical model is satisfying [fr

  13. Self-consistent radial sheath

    International Nuclear Information System (INIS)

    Hazeltine, R.D.

    1988-12-01

    The boundary layer arising in the radial vicinity of a tokamak limiter is examined, with special reference to the TEXT tokamak. It is shown that sheath structure depends upon the self-consistent effects of ion guiding-center orbit modification, as well as the radial variation of E /times/ B-induced toroidal rotation. Reasonable agreement with experiment is obtained from an idealized model which, however simplified, preserves such self-consistent effects. It is argued that the radial sheath, which occurs whenever confining magnetic field-lines lie in the plasma boundary surface, is an object of some intrinsic interest. It differs from the more familiar axial sheath because magnetized charges respond very differently to parallel and perpendicular electric fields. 11 refs., 1 fig

  14. Plasma erosion switch

    International Nuclear Information System (INIS)

    Mendel, C.W. Jr.; Goldstein, S.A.; Miller, P.A.

    1976-01-01

    The plasma erosion switch is a device capable of initially carrying high currents, and then of opening in nanoseconds to stand off high voltages. It depends upon the erosion of a plasma which initially fills the switch. The sheath between the plasma and the cathode behaves as a diode with a rapidly increasing A-K gap. Preliminary tests of the switch on the Proto I accelerator at Sandia will be described. In these tests, the switch consisted of a cylinder of highly ionized plasma four inches in diameter and one-inch thick surrounding a one-inch cathode. The switch shorted out prepulse voltages and allowed energy to be stored in the diode inductance outside the switch until the accelerator current reached 75 kA. The switch impedance then rose rapidly to approximately 100 ω in 5 nanoseconds, whereupon the accelerator current transferred to the cathode. Current rise rates of 3.10 13 A/sec were limited by cathode turn-on. Voltage rise rates of 10 15 V/sec were achieved. The elimination of prepulse and machine turn-on transients allowed A-K gaps of 2 mm to be used with 2.5 MV pulses, yielding average E fields of 12 MV/cm. Staged versions of the device are being built and should improve rise rates. The switch shows promise for use with future, higher power, lower inductance machines

  15. Microfabricated triggered vacuum switch

    Science.gov (United States)

    Roesler, Alexander W [Tijeras, NM; Schare, Joshua M [Albuquerque, NM; Bunch, Kyle [Albuquerque, NM

    2010-05-11

    A microfabricated vacuum switch is disclosed which includes a substrate upon which an anode, cathode and trigger electrode are located. A cover is sealed over the substrate under vacuum to complete the vacuum switch. In some embodiments of the present invention, a metal cover can be used in place of the trigger electrode on the substrate. Materials used for the vacuum switch are compatible with high vacuum, relatively high temperature processing. These materials include molybdenum, niobium, copper, tungsten, aluminum and alloys thereof for the anode and cathode. Carbon in the form of graphitic carbon, a diamond-like material, or carbon nanotubes can be used in the trigger electrode. Channels can be optionally formed in the substrate to mitigate against surface breakdown.

  16. Controlling laser ablation plasma with external electrodes. Application to sheath dynamics study and beam physics

    International Nuclear Information System (INIS)

    Isono, Fumika; Nakajima, Mitsuo; Hasegawa, Jun; Kawamura, Tohru; Horioka, Kazuhiko

    2013-01-01

    The potential of laser ablation plasma was controlled successfully by using external ring electrodes. We found that an electron sheath is formed at the plasma boundary, which plays an important role in the potential formation. When the positively biased plasma reaches a grounded grid, electrons in the plasma are turned away and ions are accelerated, which leads to the formation of a virtual anode between the grid and an ion probe. We think that this device which can raise the plasma potential up to order of kV can be applied to the study of sheath dynamics and to a new type of ion beam extraction. (author)

  17. On self-sustainment of DC discharges with gridded anode

    Science.gov (United States)

    Yuan, Chengxun; Yao, Jingfeng; Eliseev, S. I.; Bogdanov, E. A.; Kudryavtsev, A. A.; Zhou, Zhongxiang

    2017-10-01

    The paper presents results of numerical investigation of a large-volume plasma source based on a DC discharge with gridded anode. Geometry and configuration of the electrodes were chosen so as to ensure the formation of a cathode sheath, which would accelerate electrons up to high energies and inject them into the post-anode space and create plasma. Simulations were carried out using a hybrid model, and distributions of the main discharge parameters were obtained in a wide range of currents. At low currents, cathode sheath occupies whole interelectrode gap while plasma is formed in the post-anode space. It is shown that ions moving through the anode grid into the interelectrode gap cause reduction of discharge voltage when compared to the case of classical obstructed discharge with virtually closed anode grid. At higher currents, however, plasma is formed within the interlectrode gap as well, and ions moving from plasma in the post-anode space become trapped by reversed electric field. This essentially nullifies influence of the post-anode plasma on discharge properties.

  18. Optic nerve sheath fenestration in cryptococcal meningitis

    Science.gov (United States)

    Milman, Tatyana; Mirani, Neena; Turbin, Roger E

    2008-01-01

    A patient with acquired immunodeficiency syndrome (AIDS) developed crytpococcal meningitis, complicated by papilledema and severe progressive visual loss despite medical therapy. Bilateral optic sheath fenestration resulted in significant improvement in vision and resolution of papilledema. Histopathologic evaluation of the optic nerve sheath demonstrated numerous cryptococci. Optic nerve sheath fenestration may be an effective treatment method when high intracranial pressure is contributing to visual loss, even in the presence of involvement of the optic nerve sheath by the fungus. PMID:19668765

  19. An Insoluble Titanium-Lead Anode for Sulfate Electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Ferdman, Alla

    2005-05-11

    The project is devoted to the development of novel insoluble anodes for copper electrowinning and electrolytic manganese dioxide (EMD) production. The anodes are made of titanium-lead composite material produced by techniques of powder metallurgy, compaction of titanium powder, sintering and subsequent lead infiltration. The titanium-lead anode combines beneficial electrochemical behavior of a lead anode with high mechanical properties and corrosion resistance of a titanium anode. In the titanium-lead anode, the titanium stabilizes the lead, preventing it from spalling, and the lead sheathes the titanium, protecting it from passivation. Interconnections between manufacturing process, structure, composition and properties of the titanium-lead composite material were investigated. The material containing 20-30 vol.% of lead had optimal combination of mechanical and electrochemical properties. Optimal process parameters to manufacture the anodes were identified. Prototypes having optimized composition and structure were produced for testing in operating conditions of copper electrowinning and EMD production. Bench-scale, mini-pilot scale and pilot scale tests were performed. The test anodes were of both a plate design and a flow-through cylindrical design. The cylindrical anodes were composed of cylinders containing titanium inner rods and fitting over titanium-lead bushings. The cylindrical design allows the electrolyte to flow through the anode, which enhances diffusion of the electrolyte reactants. The cylindrical anodes demonstrate higher mass transport capabilities and increased electrical efficiency compared to the plate anodes. Copper electrowinning represents the primary target market for the titanium-lead anode. A full-size cylindrical anode performance in copper electrowinning conditions was monitored over a year. The test anode to cathode voltage was stable in the 1.8 to 2.0 volt range. Copper cathode morphology was very smooth and uniform. There was no

  20. Salt, caprock, and sheath study

    International Nuclear Information System (INIS)

    Karably, L.S. Jr.; Jernigan, B.L.; Petre, I.C.; Sullivan, J.M.

    1983-01-01

    Salt domes of the Gulf Coast region of the United States consist of four component parts: 1) a salt stock, 2) caprock material, 3) sheath material, and 4) the surrounding upturned sediments. Salt stock consists of remarkably pure halite (NaCl), which represents 90 to 99% of the total mass, with the major impurity being anhydrite. Salt stocks are markedly homogeneous and continuous with respect to composition, texture and structure. Caprock consists primarily of anhydrite, gypsum and calcite which commonly occur in monomineralic zones oriented roughly parallel to the top of the salt stock. Caprock composition varies markedly over any single salt stock as well as from one salt stock to another. Fracturing, porosity and permeability of caprock material are correspondingly variable, but are usually developed tto a higher degree in the upper portions of caprock; porosity and permeability may also be relatively high at the caprock-salt interface. Caprock is generally believed to form by residual accumulation of anhydrite from the dissolution of salt, with subsequent alteration of the anhydrite to calcite and gypsum. Sheath material, probably a mixture of sedimentary rocks (clastic and evaporite), formed as a result of mechanical interaction between the salt stock and surrounding sediments during diapirism. Sheath material is thought to be distributed throughout an external zone, consisting mainly of disturbed sediment, and an internal zone, consisting mainly of disturbed salt. Sheath material forms along a roughly cylindrical shear zone which encloses thesalt stock. Sheath material may be overpressured and is generally thought to be impermeable. Upturned sediments around the salt diapirs are the result of dome genesis; hovever, these sedimentary beds and other structures are beyond the scope of this report

  1. Influence of the inter-electrode gap on the cathode sheath characteristics (voltage drop across it and its thickness)

    Science.gov (United States)

    Lisovskiy, V. A.; Artushenko, K. P.; Yegorenkov, V. D.

    2017-05-01

    This paper is devoted to studying how the inter-electrode distance affects the voltage drop across electrodes, the cathode sheath thickness, and the axial distribution of plasma parameters. The experiment demonstrates the simultaneous growth of both the voltage drop across the electrodes and the cathode sheath thickness when on increasing the gap the anode is moved away from the cathode while remaining in the negative glow. This effect is most clearly pronounced under low gas pressure and high current values when the negative glow length is large. The discharge axial structure dynamics is studied with the Langmuir probe technique and with the OOPIC Pro code. The inter-electrode gap growth with the current fixed is found to be accompanied by the plasma concentration increase in the negative glow. The positive plasma potential is shown to cause the current to the grounded anode to be transported by fast electrons accelerated in the cathode sheath. Moving the anode away from the cathode through the negative glow weakens the flow of fast electrons coming to the anode, thus decreasing the discharge current. In order to restore the discharge current, one has to increase the voltage across the electrodes, leading to the cathode sheath thickness increase and the plasma concentration growth in the negative glow.

  2. Electromagnetic particle in cell modeling of the plasma focus: Current sheath formation and lift off

    International Nuclear Information System (INIS)

    Seng, Y. S.; Lee, P.; Rawat, R. S.

    2014-01-01

    The shaping and formation of the current sheath takes place in the breakdown phase of a plasma focus device and critically controls the device performance. Electrostatic particle in cell codes, with magnetic effects ignored, have been used to model the breakdown phase. This Letter reports the successful development and implementation of an electromagnetic particle in cell (EMPIC) code, including magnetic effects self-consistently, to simulate the breakdown phase; from the ionization, localization and gliding discharge along the insulator to the time instant of current sheath lift off. The magnetic field was found to be appreciable from the time the current sheath came into contact with the anode with increased local current, initiating the voltage breakdown of the device as a result

  3. Theoretical Investigation of a Hot Refractory Anode Vacuum Arc

    International Nuclear Information System (INIS)

    Beilis, I.I.; Boxman, R.L.; Goldsmith, S.

    1999-01-01

    , and anode sheath potential drop is 2.2 to 3 V. Calculated plasma and anode parameters agreed well with observed data

  4. New technique for withdrawing broken sheath

    Directory of Open Access Journals (Sweden)

    Süleyman Cagan Efe

    2016-03-01

    Full Text Available A sheath that is broken inside vessel is a rare complication, and intravascular fragments from broken sheaths are retrieving transcutaneously by techniques including the loop snare catheter, basket catheter, and grasping/biopsy forceps. We reported a less common type of broken central venous sheath in location and a successful unique technique for retrieving it from subclavian vein by using noncompliant balloon from 40 year old female patient.

  5. Experimental restoration of the digital synovial sheath.

    Science.gov (United States)

    Eiken, O; Rank, F

    1977-01-01

    The digital synovial sheath constitutes an important component of the delicate mechanism of flexor tendon nutrition and gliding function, In the present study the true nature of the inner cell layers of secondary healed defects in the tendon sheath as well as of free tendon sheath autografts were studied. Leghorn chickens were used as experimental animals and the gradual development of the pseudosheath as well as the healing of sheath autografts were studied both macroscopically and histologically including transmission electron miscroscopy. Synovial regeneration by extension from intact parts of the sheath was never observed and the pseudosheath formed around silastic rods consisted of granulation tissue with fibroblasts and macrophages. The free tendon sheath autografts demonstrated a normal process of healing at the edges of the defect. Synovial regeneration appeared to be that of metaplasia and proliferation of fibroblasts and macrophages. This phenomenon was demonstrable both in the secondary healed defects and more convincingly in the sheath autografts. Further, the silastic rod was found to induce foreign body reaction in the healing synovium. It is concluded that grafting of autologous tendon sheath tissue seems to be a promising method for restoration of defects in the digital tendon sheath.

  6. Theory and simulation of anode spots in low pressure plasmas

    Science.gov (United States)

    Scheiner, Brett; Barnat, Edward V.; Baalrud, Scott D.; Hopkins, Matthew M.; Yee, Benjamin T.

    2017-11-01

    When electrodes are biased above the plasma potential, electrons accelerated through the associated electron sheath can dramatically increase the ionization rate of neutrals near the electrode surface. It has previously been observed that if the ionization rate is great enough, a double layer separates a luminous high-potential plasma attached to the electrode surface (called an anode spot or fireball) from the bulk plasma. Here, results of the first 2D particle-in-cell simulations of anode spot formation are presented along with a theoretical model describing the formation process. It is found that ionization leads to the build-up of an ion-rich layer adjacent to the electrode, forming a narrow potential well near the electrode surface that traps electrons born from ionization. It is shown that anode spot onset occurs when a quasineutral region is established in the potential well and the density in this region becomes large enough to violate the steady-state Langmuir condition, which is a balance between electron and ion fluxes across the double layer. A model for steady-state properties of the anode spot is also presented, which predicts values for the anode spot size, double layer potential drop, and form of the sheath at the electrode by considering particle, power, and current balance. These predictions are found to be consistent with the presented simulation and previous experiments.

  7. Optic nerve sheath fenestration in cryptococcal meningitis

    Directory of Open Access Journals (Sweden)

    Tatyana Milman

    2008-10-01

    Full Text Available Tatyana Milman1, Neena Mirani1,2, Roger E Turbin11Ophthalmology Department, Institute of Ophthalmology and Visual Science, 2Pathology Department, University Hospital, New Jersey Medical School, Newark, NJ, USAAbstract: A patient with acquired immunodeficiency syndrome (AIDS developed crytpococcal meningitis, complicated by papilledema and severe progressive visual loss despite medical therapy. Bilateral optic sheath fenestration resulted in significant improvement in vision and resolution of papilledema. Histopathologic evaluation of the optic nerve sheath demonstrated numerous cryptococci. Optic nerve sheath fenestration may be an effective treatment method when high intracranial pressure is contributing to visual loss, even in the presence of involvement of the optic nerve sheath by the fungus.Keywords: optic nerve sheath, cryptococcal, meningitis, fenestration

  8. Primary optic nerve sheath meningioma

    Energy Technology Data Exchange (ETDEWEB)

    Jeremic, Branislav [International Atomic Energy Agency, Vienna (Austria); Pitz, Susanne (eds.) [University Eye Hospital, Mainz (Germany)

    2008-07-01

    Optic nerve sheath meningioma (ONSM) is a rare tumour. Cases are usually separated into primary ONSM, which arises either intraorbitally or, less commonly, intracanalicularly, and secondary ONSM, which arises intracranially and subsequently invades the optic canal and orbit. This is the first book to cover all important aspects of the diagnosis and treatment of primary ONSM. After a general introduction, individual chapters discuss the clinical presentation, clinical examination and diagnosis, imaging, and histology. Treatment options are then addressed in detail, with special emphasis on external beam radiation therapy, and in particular stereotactic fractionated radiation therapy. The latter has recently produced consistently good results and is now considered the emerging treatment of choice for the vast majority of patients with primary ONSM. This well-illustrated book will prove invaluable to all practitioners who encounter primary ONSM in their clinical work. (orig.)

  9. FLUORINE CELL ANODE ASSEMBLY

    Science.gov (United States)

    Cable, R.E.; Goode, W.B. Jr.; Henderson, W.K.; Montillon, G.H.

    1962-06-26

    An improved anode assembly is deslgned for use in electrolytlc cells ln the productlon of hydrogen and fluorlne from a moIten electrolyte. The anode assembly comprises a copper post, a copper hanger supported by the post, a plurality of carbon anode members, and bolt means for clamplng half of the anode members to one slde of the hanger and for clamplng the other half of the anode members to the other slde of the hanger. The heads of the clamplng bolts are recessed withln the anode members and carbon plugs are inserted ln the recesses above the bolt heads to protect the boIts agalnst corroslon. A copper washer is provided under the head of each clamplng boIt such that the anode members can be tightly clamped to the hanger with a resultant low anode jolnt resistance. (AEC)

  10. Generalized Bohm’s criterion and negative anode voltage fall in electric discharges

    International Nuclear Information System (INIS)

    Londer, Ya. I.; Ul’yanov, K. N.

    2013-01-01

    The value of the voltage fall across the anode sheath is found as a function of the current density. Analytic solutions are obtained in a wide range of the ratio of the directed velocity of plasma electrons v 0 to their thermal velocity v T . It is shown that the voltage fall in a one-dimensional collisionless anode sheath is always negative. At the small values of v 0 /v T , the obtained expression asymptotically transforms into the Langmuir formula. Generalized Bohm’s criterion for an electric discharge with allowance for the space charge density ρ(0), electric field E(0), ion velocity v i (0), and ratio v 0 /v T at the plasma-sheath interface is formulated. It is shown that the minimum value of the ion velocity v i * (0) corresponds to the vanishing of the electric field at one point inside the sheath. The dependence of v i * (0) on ρ(0), E(0), and v 0 /v T determines the boundary of the existence domain of stationary solutions in the sheath. Using this criterion, the maximum possible degree of contraction of the electron current at the anode is determined for a short high-current vacuum arc discharge

  11. Theory of ion-matrix-sheath dynamics

    Science.gov (United States)

    Kos, L.; Tskhakaya, D. D.

    2018-01-01

    The time evolution of a one-dimensional, uni-polar ion sheath (an "ion matrix sheath") is investigated. The analytical solutions for the ion-fluid and Poisson's equations are found for an arbitrary time dependence of the wall-applied negative potential. In the case that the wall potential is large and remains constant after its ramp-up application, the explicit time dependencies of the sheath's parameters during the initial stage of the process are given. The characteristic rate of approaching the stationary state, satisfying the Child-Langmuir law, is determined.

  12. Float level switch for a nuclear power plant containment vessel

    Science.gov (United States)

    Powell, J.G.

    1993-11-16

    This invention is a float level switch used to sense rise or drop in water level in a containment vessel of a nuclear power plant during a loss of coolant accident. The essential components of the device are a guide tube, a reed switch inside the guide tube, a float containing a magnetic portion that activates a reed switch, and metal-sheathed, ceramic-insulated conductors connecting the reed switch to a monitoring system outside the containment vessel. Special materials and special sealing techniques prevent failure of components and allow the float level switch to be connected to a monitoring system outside the containment vessel. 1 figures.

  13. Sheath rot of rice in Iran.

    Science.gov (United States)

    Naeimi, S; Okhovvat, S M; Hedjaroude, G A; Khosravi, V

    2003-01-01

    Sheath rot of rice occurs in most rice-growing regions of the world. It usually causes yield losses from 20 to 85%. Sheath rot was reported from Iran in 1993. Year after year, the number of diseased plants increased in the Northern Iran. In summer of 2001, these symptoms were observed in most fields: lesions occur on the upper leaf sheaths, especially the flag leaf sheath. As the disease progresses, lesions enlarge and coalesce and may cover most of the leaf sheath. Panicle may fail to completely or at all. Brown or partially brown not filled or partially filled grain is also associated with infection of the panicle. A whitish powdery growth may be found inside affected sheaths. Infected plants were collected and trasferred to laboratory. Small pieces of diseased tissues were washed under tap water for one hour. Then tissues were placed on WA and incubated at 25 degrees C. These isolates were purified and identified as: Sarocladium oryzae, Fusarium udum, F. semitectum, F. avenaceum, F. flocciferum, F. graminearum, Bipolaris oryzae, Alternaria padwickii, Rhizoctonia solani, Paecilomyces sp., Nigrospora sp. and Trichoderma sp. This is the first report of F. udum in Iran. Also this is the first report that rice is the host for F. semitectum, F. avenaceum and F. flocciferum in Iran. Pathogenicity tests were conducted in glass house. Following species were found to be associated with sheath rot of rice: S. oryzae, F. graminearum, F. udum, F. avenaceum, B. oryzae, A. padwickii. This is the first report in the world that F. udum and A. padwickii are the causal agents of the sheath rot on rice plants.

  14. A sheath model for arbitrary radiofrequency waveforms

    Science.gov (United States)

    Turner, M. M.; Chabert, Pascal

    2012-10-01

    The sheath is often the most important region of a rf plasma, because discharge impedance, power absorption and ion acceleration are critically affected by the behaviour of the sheath. Consequently, models of the sheath are central to any understanding of the physics of rf plasmas. Lieberman has supplied an analytical model for a radio-frequency sheath driven by a single frequency, but in recent years interest has been increasing in radio-frequency discharges excited by increasingly complex wave forms. There has been limited success in generalizing the Lieberman model in this direction, because of mathematical complexities. So there is essentially no sheath model available to describe many modern experiments. In this paper we present a new analytical sheath model, based on a simpler mathematical framework than that of Lieberman. For the single frequency case, this model yields scaling laws that are identical in form to those of Lieberman, differing only by numerical coefficients close to one. However, the new model may be straightforwardly solved for arbitrary current waveforms, and may be used to derive scaling laws for such complex waveforms. In this paper, we will describe the model and present some illustrative examples.

  15. Theory of the Electron Sheath and Presheath

    Science.gov (United States)

    Scheiner, Brett; Baalrud, Scott; Yee, Benjamin; Hopkins, Matthew; Barnat, Edward

    2015-09-01

    Electron sheaths are commonly found near Langmuir probes collecting the electron saturation current. The common assumption is that the probe collects the random flux of electrons incident on the sheath, which tacitly implies that there is no electron presheath and that the flux collected is due to a velocity space truncation of the velocity distribution function (VDF). This work provides a dedicated theory of electron sheaths, which suggests that electron sheaths are not so simple. Motivated by VDFs observed in recent Particle-In-Cell (PIC) simulations, we develop a 1D model for the electron sheath and presheath. In the model, under low temperature plasma conditions, an electron pressure gradient accelerates electrons in the presheath to a flow velocity that exceeds the electron thermal speed at the sheath edge. This pressure gradient allows the generation of large flows compared to those that would be generated by the electric field alone. It is due to this pressure gradient that the electron presheath extends much further into the plasma (nominally by a factor of √{mi /me }) than an analogous ion presheath. Results of the model are compared with PIC simulations. This work was supported by the Office of Fusion Energy Science at the U.S. Department of Energy under contract DE-AC04-94SL85000 and by the Office of Science Graduate Student Research (SCGSR) program under Contract Number DE-AC05-06OR23100.

  16. [Experimental study of allogenic tendon with sheath grafting in chicken].

    Science.gov (United States)

    Zhang, Y L; Wang, S L; Gao, X S

    2001-03-01

    To investigate availability of deep freeze stored allogenic tendon with sheath grafting in repairing the tendon and sheath defect in the II area of flexor digitorum tendon. Sixty chickens with tendon and sheath defect were divided into 2 groups randomly, group A was treated with allogenic grafting and group B was treated with autogenic grafting, these two groups were divided into two subgroups respectively, they were, group A1 allogenic tendon with whole sheath grafting, group A2 allogenic tendon with partial sheath grafting, group B1 autogenic tendon with whole sheath grafting and group B2 autogenic tendon with whole sheath grafting. All the allogenic grafts were treated by deep freeze. Histomorphological study, histoimmunological study and slipping function of the grafts were measured after operation. In group A1 and B1, the local reaction was sever, the nutrition of tendon graft was barricaded by the whole sheath resulting in adhesion, degeneration and necrosis. In group A2 and B2, the tendon graft healed well and little adhesion existed between tendon and sheath. The results showed that there were significant differences between tendon grafting with whole sheath and tendon grafting with partial sheath. Deep freeze store can reduce the immunogenicity of allogenic tendon with sheath. Allogenic tendon with partial sheath grafting can be used as a new biological material for repairing the tendon and sheath defect.

  17. Polarization force-induced changes in the dust sheath formation

    Energy Technology Data Exchange (ETDEWEB)

    Mayout, Saliha; Bentabet, Karima; Tribeche, Mouloud [Plasma Physics Group (PPG), Theoretical Physics Laboratory (TPL), Faculty of Physics, University of Bab-Ezzouar, USTHB, BP 32, El Alia, Algiers 16111 (Algeria)

    2015-09-15

    The modifications arising in the dusty plasma sheath structure due to the presence of polarization forces acting on the dust grains are investigated. The corresponding appropriate Bohm criterion for sheath formation is obtained. It is found that the critical Mach number, beyond which the dusty plasma electrostatic sheath sets in, decreases whenever the polarization effects become important. In addition, when the polarization force dominates over the electrical one, the dust plasma sheath cannot set in. This happens whenever the dust grain size exceeds a critical threshold. Moreover, the sheath electrostatic potential-gradient becomes abruptly steep, and the sheath thickness becomes broader as the polarization force effects strengthen.

  18. Anodized dental implant surface

    Directory of Open Access Journals (Sweden)

    Sunil Kumar Mishra

    2017-01-01

    Full Text Available Purpose: Anodized implants with moderately rough surface were introduced around 2000. Whether these implants enhanced biologic effect to improve the environment for better osseointegration was unclear. The purpose of this article was to review the literature available on anodized surface in terms of their clinical success rate and bone response in patients till now. Materials and Methods: A broad electronic search of MEDLINE and PubMed databases was performed. A focus was made on peer-reviewed dental journals. Only articles related to anodized implants were included. Both animal and human studies were included. Results: The initial search of articles resulted in 581 articles on anodized implants. The initial screening of titles and abstracts resulted in 112 full-text papers; 40 animal studies, 16 studies on cell adhesion and bacterial adhesion onto anodized surfaced implants, and 47 human studies were included. Nine studies, which do not fulfill the inclusion criteria, were excluded. Conclusions: The long-term studies on anodized surface implants do favor the surface, but in most of the studies, anodized surface is compared with that of machined surface, but not with other surfaces commercially available. Anodized surface in terms of clinical success rate in cases of compromised bone and immediately extracted sockets has shown favorable success.

  19. Injection inside the paraneural sheath of the sciatic nerve

    DEFF Research Database (Denmark)

    Andersen, Henning Lykke; Andersen, Sofie L; Tranum-Jensen, Jørgen

    2012-01-01

    There exists little anatomic knowledge regarding the structure and sonographic features of the sheath enveloping the sciatic nerve in the popliteal fossa. We investigated the spread of an injection inside the sheath to (1) determine whether the sheath is a structure distinct from the nerve or par...

  20. Anode Support Creep

    DEFF Research Database (Denmark)

    2015-01-01

    Initial reduction temperature of an SOC is kept higher than the highest intended operation temperature of the SOC to keep the electrolyte under compression by the Anode Support at all temperatures equal to and below the maximum intended operation temperature.......Initial reduction temperature of an SOC is kept higher than the highest intended operation temperature of the SOC to keep the electrolyte under compression by the Anode Support at all temperatures equal to and below the maximum intended operation temperature....

  1. Liquid Silicon Pouch Anode

    Science.gov (United States)

    2017-09-06

    collector 18 can be made from nickel; however, other high conductivity metals and alloys can be used for this such as gold, silver , platinum, alloys of...The conductive particles can be carbon such as carbon black or graphite. These particles can also be metals such as copper, nickel, silver , gold...anode cycling characteristics, higher battery capacity, and longer cycle life. [0005] Rechargeable batteries with lithium metal anodes have been

  2. Plasma sheath properties calculated using measured secondary electron emission coefficients

    International Nuclear Information System (INIS)

    Pedgley, J.M.; McCracken, G.M.

    1993-01-01

    Measurements of secondary electron emission (SEE) are presented for graphite, hydrogen-implanted graphite and an amorphous graphite (a-C:H) carbon layer, over a wide range of energies and angles of incidence. These data have been integrated over a Maxwellian velocity distribution to simulate the effect of SEE due to plasma electrons. The SEE yields have then been used to calculate plasma sheath potentials, sheath heat transmission coefficients and sputtering yields for a range of ions as a function of plasma temperature. The increased SEE yield with temperature reduces the normalized sheath potential and increases the sheath transmission coefficient markedly. The role of space charge in the sheath is discussed. (Author)

  3. Pseudospark switches

    International Nuclear Information System (INIS)

    Billault, P.; Riege, H.; Gulik, M. van; Boggasch, E.; Frank, K.

    1987-01-01

    The pseudospark discharge is bound to a geometrical structure which is particularly well suited for switching high currents and voltages at high power levels. This type of discharge offers the potential for improvement in essentially all areas of switching operation: peak current and current density, current rise, stand-off voltage, reverse current capability, cathode life, and forward drop. The first pseudospark switch was built at CERN at 1981. Since then, the basic switching characteristics of pseudospark chambers have been studied in detail. The main feature of a pseudospark switch is the confinement of the discharge plasma to the device axis. The current transition to the hollow electrodes is spread over a rather large surface area. Another essential feature is the easy and precise triggering of the pseudospark switch from the interior of the hollow electrodes, relatively far from the main discharge gap. Nanosecond delay and jitter values can be achieved with trigger energies of less than 0.1 mJ, although cathode heating is not required. Pseudospark gaps may cover a wide range of high-voltage, high-current, and high-pulse-power switching at repetition rates of many kilohertz. This report reviews the basic researh on pseudospark switches which has been going on at CERN. So far, applications have been developed in the range of thyratron-like medium-power switches at typically 20 to 40 kV and 0.5 to 10 kA. High-current pseudospark switches have been built for a high-power 20 kJ pulse generator which is being used for long-term tests of plasma lenses developed for the future CERN Antiproton Collector (ACOL). The high-current switches have operated for several hundred thousand shots, with 20 to 50 ns jitter at 16 kV charging voltage and more than 100 kA peak current amplitude. (orig.)

  4. C2 root nerve sheath tumors management.

    Science.gov (United States)

    El-Sissy, Mohamed H; Mahmoud, Mostafa

    2013-05-01

    Upper cervical nerve sheath tumors (NST) arising mainly from C2 root and to lesser extent from C1 root are not uncommon, they constitute approximately 5-12% of spinal nerve sheath tumors and 18-30% of all cervical nerve sheath tumors, unique in presentation and their relationship to neighbouring structures owing to the discrete anatomy at the upper cervical-craniovertebral region, and have atendency for growth reaching large-sized tumors before manifesting clinically due to the capacious spinal canal at this region; accordingly the surgical approaches to such tumors are modified. The aim of this paper is to discuss the surgical strategies for upper cervical nerve sheath tumors. Eleven patients (8 male and 3 females), age range 28-63 years, with C2 root nerve sheath tumors were operated upon based on their anatomical relations to the spinal cord. The magnetic resonance imaging findings were utilized to determine the surgical approach. The tumors had extra- and intradural components in 10 patients, while in one the tumor was purely intradural. The operative approaches included varied from extreme lateral transcondylar approach(n = 1) to laminectomy, whether complete(n = 3) a or hemilaminectomy(n = 7), with partial facetectomy(n = 7), and with suboccipital craniectomy(n = 2). The clinical picture ranged from spasticity (n = 8, 72,72 %), tingling and numbness below neck (n = 6, 54,54 %), weakness (n = 6, 54,54 %), posterior column involvement (n = 4, 26,36 %), and neck pain (n = 4, 36,36 %). The duration of symptoms ranged from 1 to 54 months, total excision was performed in 7 patients; while in 3 patients an extraspinal component, and in 1 patient a small intradural component, were left in situ. Eight patients showed improvement of myelopathy; 2 patients maintained their grades. One poor-grade patient was deteriorated. The surgical approaches for the C2 root nerve sheath tumors should be tailored according to the relationship to the spinal cord, determined by magnetic

  5. Switching antidepressants

    African Journals Online (AJOL)

    depressive disorder, with response rates of 50-60%. Switching within or between classes of antidepressants is often required in patients with an insufficient response to SSRIs.12 Because they share a similar mechanism of action, the immediate substitution of one SSRI for another is probably the easiest switching option.

  6. Unified model of the rf plasma sheath

    Energy Technology Data Exchange (ETDEWEB)

    Riley, M.E.

    1995-05-01

    By developing an approximation to the first integral of the Poisson equation, one can obtain solutions for the voltage-current characteristics of a radio-frequency (rf) plasma sheath that are valid over the whole range of inertial response of the ions to an imposed rf voltage or current-specified conditions. The theory adequately reproduces the time-dependent voltage-current characteristics of the two extreme cases corresponding to the Lieberman rf sheath theory and the Metze-Ernie-Oskam theory. Contained within the approximation is a time constant which controls the amount of ion response to the rf electric field. A prescription is given for determining this ion relaxation time constant, which also determines the time-dependent ion impact energy on the electrode surface.

  7. Lithium batteries, anodes, and methods of anode fabrication

    KAUST Repository

    Li, Lain-Jong

    2016-12-29

    Prelithiation of a battery anode carried out using controlled lithium metal vapor deposition. Lithium metal can be avoided in the final battery. This prelithiated electrode is used as potential anode for Li- ion or high energy Li-S battery. The prelithiation of lithium metal onto or into the anode reduces hazardous risk, is cost effective, and improves the overall capacity. The battery containing such an anode exhibits remarkably high specific capacity and a long cycle life with excellent reversibility.

  8. Optic Nerve Sheath Mechanics in VIIP Syndrome

    Science.gov (United States)

    Raykin, Julia; Forte, Taylor E.; Wang, Roy; Feola, Andrew; Samuels, Brian; Myers, Jerry; Nelson, Emily; Gleason, Rudy; Ethier, C. Ross

    2016-01-01

    Visual Impairment Intracranial Pressure (VIIP) syndrome is a major concern in current space medicine research. While the exact pathology of VIIP is not yet known, it is hypothesized that the microgravity-induced cephalad fluid shift increases intracranial pressure (ICP) and drives remodeling of the optic nerve sheath. To investigate this possibility, we are culturing optic nerve sheath dura mater samples under different pressures and investigating changes in tissue composition. To interpret results from this work, it is essential to first understand the biomechanical response of the optic nerve sheath dura mater to loading. Here, we investigated the effects of mechanical loading on the porcine optic nerve sheath.Porcine optic nerves (number: 6) were obtained immediately after death from a local abattoir. The optic nerve sheath (dura mater) was isolated from the optic nerve proper, leaving a hollow cylinder of connective tissue that was used for biomechanical characterization. We developed a custom mechanical testing system that allowed for unconfined lengthening, twisting, and circumferential distension of the dura mater during inflation and under fixed axial loading. To determine the effects of variations in ICP, the sample was inflated (0-60 millimeters Hg) and circumferential distension was simultaneously recorded. These tests were performed under variable axial loads (0.6 grams - 5.6 grams at increments of 1 gram) by attaching different weights to one end of the dura mater. Results and Conclusions: The samples demonstrated nonlinear behavior, similar to other soft connective tissue (Figure 1). Large increases in diameter were observed at lower transmural pressures (approximately 0 to 5 millimeters Hg), whereas only small diameter changes were observed at higher pressures. Particularly interesting was the existence of a cross-over point at a pressure of approximately 11 millimeters Hg. At this pressure, the same diameter is obtained for all axial loads applied

  9. Magnetic switching

    International Nuclear Information System (INIS)

    Kirbie, H.C.

    1989-01-01

    Magnetic switching is a pulse compression technique that uses a saturable inductor (reactor) to pass pulses of energy between two capacitors. A high degree of pulse compression can be achieved in a network when several of these simple, magnetically switched circuits are connected in series. Individual inductors are designed to saturate in cascade as a pulse moves along the network. The technique is particularly useful when a single-pulse network must be very reliable or when a multi-pulse network must operate at a high pulse repetition frequency (PRF). Today, magnetic switches trigger spark gaps, sharpen the risetimes of high energy pulses, power large lasers, and drive high PRF linear induction accelerators. This paper will describe the technique of magnetic pulse compression using simple networks and design equations. A brief review of modern magnetic materials and of their role in magnetic switch design will be presented. 12 refs., 8 figs

  10. Investigation of the short argon arc with hot anode. I. Numerical simulations of non-equilibrium effects in the near-electrode regions

    Science.gov (United States)

    Khrabry, A.; Kaganovich, I. D.; Nemchinsky, V.; Khodak, A.

    2018-01-01

    The atmospheric pressure arcs have recently found application in the production of nanoparticles. The distinguishing features of such arcs are small length and hot ablating anode characterized by intensive electron emission and radiation from its surface. We performed a one-dimensional modeling of argon arc, which shows that near-electrode effects of thermal and ionization non-equilibrium play an important role in the operation of a short arc, because the non-equilibrium regions are up to several millimeters long and are comparable to the arc length. The near-anode region is typically longer than the near-cathode region and its length depends more strongly on the current density. The model was extensively verified and validated against previous simulation results and experimental data. The Volt-Ampere characteristic (VAC) of the near-anode region depends on the anode cooling mechanism. The anode voltage is negative. In the case of strong anode cooling (water-cooled anode) when the anode is cold, temperature and plasma density gradients increase with current density, resulting in a decrease of the anode voltage (the absolute value increases). Falling VAC of the near-anode region suggests the arc constriction near the anode. Without anode cooling, the anode temperature increases significantly with the current density, leading to a drastic increase in the thermionic emission current from the anode. Correspondingly, the anode voltage increases to suppress the emission, and the opposite trend in the VAC is observed. The results of simulations were found to be independent of sheath model used: collisional (fluid) or collisionless model gave the same plasma profiles for both near-anode and near-cathode regions.

  11. Inert Anode Report

    Energy Technology Data Exchange (ETDEWEB)

    none,

    1999-07-01

    This ASME report provides a broad assessment of open literature and patents that exist in the area of inert anodes and their related cathode systems and cell designs, technologies that are relevant for the advanced smelting of aluminum. The report also discusses the opportunities, barriers, and issues associated with these technologies from a technical, environmental, and economic viewpoint.

  12. Anodes for alkaline electrolysis

    Science.gov (United States)

    Soloveichik, Grigorii Lev [Latham, NY

    2011-02-01

    A method of making an anode for alkaline electrolysis cells includes adsorption of precursor material on a carbonaceous material, conversion of the precursor material to hydroxide form and conversion of precursor material from hydroxide form to oxy-hydroxide form within the alkaline electrolysis cell.

  13. Movable anode x-ray source with enhanced anode cooling

    Science.gov (United States)

    Bird, C.R.; Rockett, P.D.

    1987-08-04

    An x-ray source is disclosed having a cathode and a disc-shaped anode with a peripheral surface at constant radius from the anode axis opposed to the cathode. The anode has stub axle sections rotatably carried in heat conducting bearing plates which are mounted by thermoelectric coolers to bellows which normally bias the bearing plates to a retracted position spaced from opposing anode side faces. The bellows cooperate with the x-ray source mounting structure for forming closed passages for heat transport fluid. Flow of such fluid under pressure expands the bellows and brings the bearing plates into heat conducting contact with the anode side faces. A worm gear is mounted on a shaft and engages serrations in the anode periphery for rotating the anode when flow of coolant is terminated between x-ray emission events. 5 figs.

  14. Laser-triggered vacuum switch

    Science.gov (United States)

    Brannon, Paul J.; Cowgill, Donald F.

    1990-01-01

    A laser-triggered vacuum switch has a material such as a alkali metal halide on the cathode electrode for thermally activated field emission of electrons and ions upon interaction with a laser beam, the material being in contact with the cathode with a surface facing the discharge gap. The material is preferably a mixture of KCl and Ti powders. The laser may either shine directly on the material, preferably through a hole in the anode, or be directed to the material over a fiber optic cable.

  15. Annihilation model of the Tormac sheath

    International Nuclear Information System (INIS)

    Hammer, J.H.

    1979-02-01

    A one-dimensional, steady state fluid model is developed to describe the boundary layer between plasma and magnetic field that occurs in the Tormac sheath. Similar systems which may be treatable by the same model are tokamaks with divertors and reversed field mirrors. The model includes transport across the magnetic field as well as mirror losses along the field, the latter being represented as annihilation terms in the one-dimensional equations. The model equations are derived from the two-dimensional, time dependent hierarchy of equations generated by taking velocity moments of the kinetic equation including collisions

  16. Paediatric laryngeal malignant nerve sheath tumour.

    Science.gov (United States)

    Lucioni, Marco; Marioni, Gino; Della Libera, Duilio; Rizzotto, Giuseppe

    2007-12-01

    Malignant nerve sheath tumours (MNSTs) are more frequently diagnosed in the extremities, the chest wall and the abdominal wall. Laryngeal MNST is an extremely rare occurrence, particularly in children. We treated a laryngeal recurrence of MNST in a 13-year-old boy with chemotherapy followed by horizontal supraglottic laryngectomy extended to left arytenoid and ipsilateral vocal fold and bilateral neck dissection. Four years later, hemithyroidectomy was performed for thyroid MNST recurrence. At present, 6 years after last intervention, the patient shows no evidence of recurrent disease.

  17. Collaborative Research: Understanding Ion Losses to Plasma Boundaries Sheaths and Presheaths

    Energy Technology Data Exchange (ETDEWEB)

    Hershkowitz, Noah [Univ. of Wisconsin, Madison, WI (United States)

    2015-10-01

    Sheaths are common to all bounded steady-state plasmas. This includes laboratory, industrial, fusion, and in some cases even space plasmas. They form in general to balance particle loss and maintain quasi-neutrality in plasmas. Electrons are lighter than the ions by 2000 times or more (depending on the gas), and in most plasmas ion temperatures are rarely higher than the electron temperature and generally much lower. Thus in most cases, negative potential sheaths occur to confine electrons and allow ions to be freely lost. We have investigated how a plasma locally response to a positive bias on a small electrode, and have established area criteria which plasma reacts differently to the positive bias – first a pure electron sheath, and a global non-ambipolar regime where all electrons are lost to the electrode, and a double layer structure identified as a virtual cathode forms to limiting electron loss and maintain quasi-neutrality, and finally a anode spot regime where a secondary discharge occurs in front of the electrode, turning it into the major loss area of the entire plasma. Electrode area and plasma parameters criteria for these regimes were established, and the effect of the virtual cathode on the electrode’s I-V characteristics was investigated. We have also developed a global non-ambipolar electron source to replace hollow cathodes in a number of plasma applications. This eliminates the lifetime limitation and maintenance cost of hollow cathodes as they easily wear out easily and cannot be replaced in space applications.

  18. The plasma-sheath boundary region

    International Nuclear Information System (INIS)

    Franklin, R N

    2003-01-01

    In this review an attempt is made to give a broad coverage of the problem of joining plasma and sheath over a wide range of physical conditions. We go back to the earliest works quoting them, where appropriate, to understand what those who introduced the various terms associated with the structure of the plasma-sheath had in mind. We try to bring out the essence of the insights that have been gained subsequently, by quoting from the literature selectively, indicating how misunderstandings have arisen. In order to make it accessible to the generality of those currently working in low temperature plasmas we have sought to avoid mathematical complexity but retain physical insight, quoting from published work where appropriate. Nevertheless, in clarifying my own ideas I have found it necessary to do additional original work in order to give a consistent picture. In this way I have sought to bring together work in the late 1920s, the 1960s, and now mindful of the commercial importance of plasma processing, work over the past 15 years that adds to the general understanding. (topical review)

  19. Theory of sheath in a collisional multi-component plasma

    Indian Academy of Sciences (India)

    gate the interaction between a dusty plasma and a solid boundary. It has been mentioned that dust strongly influences all parameters of the sheath, in par- ticular, the electric field distributions and the ion flow velocities. The electric field of dust particles contributes to the distribution of the electric potential in the sheath and ...

  20. Retrospective analysis of oral peripheral nerve sheath tumors in Brazilians

    Directory of Open Access Journals (Sweden)

    Juliana Tito Salla

    2009-03-01

    Full Text Available Traumatic neuroma, neurofibroma, neurilemmoma, palisaded encapsulated neuroma and malignant peripheral nerve sheath tumor (MPNST are peripheral nerve sheath tumors and present neural origin. The goal of this study was to describe the epidemiological data of oral peripheral nerve sheath tumors in a sample of the Brazilian population. Biopsies requested from the Oral Pathology Service, School of Dentistry, Federal University of Minas Gerais (MG, Brazil, between 1966 and 2006 were evaluated. Lesions diagnosed as peripheral nerve sheath tumors were submitted to morphologic and to immunohistochemical analyses. All cases were immunopositive to the S-100 protein. Thirty-five oral peripheral nerve sheath tumors were found, representing 0.16% of all lesions archived in the Oral Pathology Service. Traumatic neuroma (15 cases most frequently affected the mental foramen. Solitary neurofibroma (10 cases was more frequently observed in the palate. Neurofibroma associated with neurofibromatosis type I (2 cases was observed in the gingival and alveolar mucosa. Neurilemmoma (4 cases was more commonly observed in the buccal mucosa. Malignant peripheral nerve sheath tumors (3 cases occurred in the mandible, palate, and tongue. Palisaded encapsulated neuroma (1 case occurred in the buccal mucosa. The data confirmed that oral peripheral nerve sheath tumors are uncommon in the oral region, with some lesions presenting a predilection for a specific gender or site. This study may be useful in clinical dentistry and oral pathology practice and may be used as baseline data regarding oral peripheral nerve sheath tumors in other populations.

  1. Fine-needle aspiration cytology of malignant nerve sheath tumors.

    Science.gov (United States)

    Vendraminelli, R; Cavazzana, A O; Poletti, A; Galligioni, A; Pennelli, N

    1992-01-01

    Precise preoperative diagnosis of three malignant nerve sheath tumors (MNST) was based on their remarkably uniform and highly characteristic cytologic appearance. The differential diagnosis with benign nerve sheath tumors and other spindle cell sarcomas is addressed, and the possibility of achieving confident diagnosis on cytologic material from at least some soft-tissue sarcomas is confirmed.

  2. Significance of rice sheath photosynthesis: Yield determination by ...

    African Journals Online (AJOL)

    Using high-yielding hybrid rice Liangyopeijiu (LYP9), its male parent 9311 and hybrid rice Shanyou 63 (SY63) as the experimental materials, the photosynthesis of rice sheath was studied by 14C radio-autography. The results showed that rice sheath could trap sunlight and produce photosynthates, and these ...

  3. Usefulness of a Guiding Sheath for Fluoroscopic Colorectal Stent Placement

    Science.gov (United States)

    Nam, Deok Ho; Lee, Heuiran

    2012-01-01

    Objective To investigate the technical feasibility, clinical usefulness, and safety of a guiding sheath in fluoroscopic stent placement for patients with malignant colorectal obstructions. Materials and Methods Between June 2007 and January 2011, fluoroscopic placement of a dual colorectal stent was attempted in a total of 97 patients with malignant colorectal obstructions. A polytetrafluoroethylene guiding sheath was used in patients in whom a stent delivery system failed to reach the obstruction. Usefulness of the sheath was evaluated depending on whether the sheath could successfully assist the stent delivery system reach its area of interest. Results The guiding sheath was needed in 22 patients (15 men, 7 women; age range, 33-77 years; mean age, 59 years). The overall success rate for passing the sheath to the area of interest was 100%. There were no procedure-related deaths or major complications. The majority of the patients reported mild discomfort. In 2 of 22 patients with successful passing of the sheath to the area of interest, stent placement failed because of failure in the negotiation of a guide wire through the obstruction. Conclusion Using a guiding sheath seems to be easy, safe and useful in fluoroscopic stent placement for patients with malignant colorectal obstructions. PMID:22563292

  4. sheath characteristics in multi-component plasma with negative ions

    Indian Academy of Sciences (India)

    under this condition is known as the dissociative attachment process, which re- duces the electron population in the plasma. For the quasi-neutral bulk plasma, .... the theory [2,3], the positive ion drift speed toward the sheath estimated from the experimentally measured pre-sheath potential is found to decrease with ...

  5. Electrospinning jet behaviors under the constraints of a sheath gas

    Directory of Open Access Journals (Sweden)

    Yang Zhao

    2016-11-01

    Full Text Available Increasing the ejection efficiency and uniformity of nanofibers is the key to applications of electrospinning technology. In this work, a novel electrospinning spinneret with a sheath gas passageway is designed. The frictional resistance that stems from the sheath gas provides additional stretching and restriction forces on the jet. The sheath gas also reduces interference and enhances the stability of the charged jet. A bead-on-strain simulation model is built up to determine the constraint effects of the sheath gas. Simulation results show that the sheath gas decreases the motion area and increases the stretching ratio of the liquid jet. The stretching force from the sheath gas decreases the diameter and increases the uniformity of the nanofiber. As the gas pressure increases from 0 kPa to 50 kPa, the critical voltage of the jet ejection decreases from 8.4 kV to 2.5 kV, the diameter of the nanofiber deposition zone decreases from 40 cm to 10 cm, and the diameter of the nanofibers decreases from 557.97 nm to 277.73 nm. The uniformity of nanofibers can be improved significantly using a sheath gas. The sheath gas contributes to the rapid deposition of a uniform nanofibrous membrane and the industrial applications of electrospinning.

  6. The Twin Amplatz Sheath Method: A Modified Technique of ...

    African Journals Online (AJOL)

    ... dilators and a 28 Fr Amplatz sheath was guided into the bladder and the foot end of the table lowered to 20° to facilitate high-speed outfl ow of irrigant and stone particles. A 26.5 Fr nephroscope was passed through the suprapubic Amplatz sheath and the stone was fragmented by intracorporeal pneumatic device keeping

  7. Simulation of plasma erosion opening switches

    International Nuclear Information System (INIS)

    Mason, R.J.; Jones, M.E.

    1988-01-01

    Recent progress in the modeling of Plasma Erosion Opening Switches is reviewed, and new results from both fluid and particle simulation compared. Three-fluid simulations with the ANTHEM code for switches on the NRL GAMBLE I machine and SNL PBFA II machine have shown strong dependence of the opening dynamics on the anode structure, the threshold for electron emission, on the possible presence of anomalous resistivity, and on advection of the magnetic field with cathode emitted electrons. Simulations with the implicit particle-in-cell code ISIS confirm these observations, but manifest broader current channels---in better agreement with GAMBLE I experimental results. 7 refs., 3 figs

  8. Plasma opening switch for long-pulse intense ion beam

    International Nuclear Information System (INIS)

    Davis, H.A.; Mason, R.J.; Bartsch, R.R.; Greenly, J.B.; Rej, D.J.

    1993-01-01

    A Plasma Opening Switch (POS) is being developed at Los Alamos, as part of an intense ion beam experiment with special application to materials processing. The switch must conduct up to 100 kA for 400 ns, and open quicky to avoid premature gap closure in the ion beam diode load. Power multiplication is not a necessity, but prepulse suppression is. A positive central polarity is desirable, since with it an ion beam can be conveniently launched beyond the switch from the central anode toward a negatively charged target. Using traditional scaling rules, a POS was designed with a 1.25 cm radius inner anode, and a 5.0 cm radius outer cathode. This has been constructed, and subjected to circuit, and simulational analysis. The computations are being performed with the 2D ANTHEM implicit code. Preliminary results show a marked difference in switching dynamics, when the central positive polarity is used in place of the more conventional opposite choice. Opening is achieved by the fast development of a central anode magnetic layer, rather than by the more conventional slow evolution of a cathode gap. With the central anode, higher fill densities are needed to achieve desired conduction times. This has suggested switch design improvements, which are discussed

  9. Intrinsic nanofilamentation in resistive switching

    KAUST Repository

    Wu, Xing

    2013-03-15

    Resistive switching materials are promising candidates for nonvolatile data storage and reconfiguration of electronic applications. Intensive studies have been carried out on sandwiched metal-insulator-metal structures to achieve high density on-chip circuitry and non-volatile memory storage. Here, we provide insight into the mechanisms that govern highly reproducible controlled resistive switching via a nanofilament by using an asymmetric metal-insulator-semiconductor structure. In-situ transmission electron microscopy is used to study in real-time the physical structure and analyze the chemical composition of the nanofilament dynamically during resistive switching. Electrical stressing using an external voltage was applied by a tungsten tip to the nanosized devices having hafnium oxide (HfO2) as the insulator layer. The formation and rupture of the nanofilaments result in up to three orders of magnitude change in the current flowing through the dielectric during the switching event. Oxygen vacancies and metal atoms from the anode constitute the chemistry of the nanofilament.

  10. Structural analysis of anodic porous alumina used for resistive random access memory

    International Nuclear Information System (INIS)

    Lee, Jeungwoo; Nigo, Seisuke; Kato, Seiichi; Kitazawa, Hideaki; Kido, Giyuu; Nakano, Yoshihiro

    2010-01-01

    Anodic porous alumina with duplex layers exhibits a voltage-induced switching effect and is a promising candidate for resistive random access memory. The nanostructural analysis of porous alumina is important for understanding the switching effect. We investigated the difference between the two layers of an anodic porous alumina film using transmission electron microscopy and electron energy-loss spectroscopy. Diffraction patterns showed that both layers are amorphous, and the electron energy-loss spectroscopy indicated that the inner layer contains less oxygen than the outer layer. We speculate that the conduction paths are mostly located in the oxygen-depleted area.

  11. Characteristics of metal sheathed thermocouples in thermowell

    International Nuclear Information System (INIS)

    Okuda, Takehiro; Nakase, Tsuyoshi; Tanabe, Yutaka; Yamada, Kunitaka; Yoshizaki, Akio; Roko, Kiyokazu

    1987-01-01

    Static and dynamic characteristics of thermowell type thermocouples which are planned to be used for the High-Temperature engineering Test Reactor (HTTR) have been investigated. A mock-up test section was installed in Kawasaki's Helium Test Loop (KH-200). Thermal characteristics tests were carried out under the 600 ∼ 1000 deg C temperature conditions. The test section was equipped with four types sheathed thermocouples; the well type, the non well type, and ones with and without the thermal radiation shielding plate. The measured temperature by the well type thermocouples with the shielding plate was only about 1.3 deg C higher than the one without the shielding plate at gas temperature 990 deg C. The measured time constant of the well type thermocouples was about 7 seconds in the condition of the heat transfer coefficient 1600 Kcal/m 2 h deg C on the well surface, and coincided with the calculated one by ''TRUMP'' code. (author)

  12. Process for anodizing aluminum foil

    International Nuclear Information System (INIS)

    Ball, J.A.; Scott, J.W.

    1984-01-01

    In an integrated process for the anodization of aluminum foil for electrolytic capacitors including the formation of a hydrous oxide layer on the foil prior to anodization and stabilization of the foil in alkaline borax baths during anodization, the foil is electrochemically anodized in an aqueous solution of boric acid and 2 to 50 ppm phosphate having a pH of 4.0 to 6.0. The anodization is interrupted for stabilization by passing the foil through a bath containing the borax solution having a pH of 8.5 to 9.5 and a temperature above 80 0 C. and then reanodizing the foil. The process is useful in anodizing foil to a voltage of up to 760 V

  13. ALINE: A device dedicated to understanding radio-frequency sheaths

    Directory of Open Access Journals (Sweden)

    S. Devaux

    2017-08-01

    Full Text Available In fusion devices, radiofrequency (RF antennas are used for heating the plasma. Those antennas and the plasma interact with each other through the so-called RF sheaths, layers of plasma where the quasi-neutrality breaks down and large electric fields arise. Among the effects of RF sheaths, there is the enhancement of the particles and energy fluxes toward the surface of the antenna, which in turn generate hot spots and release impurities, which are both deleterious for plasma operations. RF sheaths comprehension stumbles on the difficulty to achieve in situ measurements of the sheath properties, as scrape-off layer plasmas are a harsh environment. The very goal of the ALINE device is to tackle this issue and to fulfil the blank between numerical simulations and full-scale experiment by providing measurements within the RF sheaths in a controlled environment. In this paper we report on the latest experimental results from ALINE, in which a cylindrical Langmuir probe mounted on a remotely controlled and programmable arm allows for plasma characterizations in the three dimensions of space around the stainless steel antenna, including the sheath. We present a series of density and potential profiles and three dimension (3D maps in the plasma surrounding a stainless-steel RF antenna as well as in the sheath itself, for unmagnetized and magnetized plasmas.

  14. Dynamic reversibility of hydrodynamic focusing for recycling sheath fluid.

    Science.gov (United States)

    Hashemi, Nastaran; Howell, Peter B; Erickson, Jeffrey S; Golden, Joel P; Ligler, Frances S

    2010-08-07

    The phenomenon of "unmixing" has been demonstrated in microfluidic mixers, but here we manipulate laminar flow streams back to their original positions in order to extend the operational utility of an analytical device where no mixing is desired. Using grooves in the channel wall, we passively focus a sample stream with two sheath streams to center it in a microchannel for optical analysis. Even though the sample stream is completely surrounded by sheath fluid, reversing the orientation of the grooves in the channel walls returns the sample stream to its original position with respect to the sheath streams. We demonstrate the separation of the sample stream from the contiguous sheath streams and the recycling of the sheath fluid using the reversibility of laminar flow. Polystyrene microspheres and fluorescent dye were used to quantify the performance of the unsheathing process. We found that the maximum numbers of microspheres and all of the fluorescent dye were recaptured at sheath recycling levels recycle the sheath fluid for long-term unattended operation.

  15. Dynamic reversibility of hydrodynamic focusing for recycling sheath fluid†

    Science.gov (United States)

    Hashemi, Nastaran; Howell, Peter B.; Erickson, Jeffrey S.; Golden, Joel P.; Ligler, Frances S.

    2010-01-01

    The phenomenon of “unmixing” has been demonstrated in microfluidic mixers, but here we manipulate laminar flow streams back to their original positions in order to extend the operational utility of an analytical device where no mixing is desired. Using grooves in the channel wall, we passively focus a sample stream with two sheath streams to center it in a microchannel for optical analysis. Even though the sample stream is completely surrounded by sheath fluid, reversing the orientation of the grooves in the channel walls returns the sample stream to its original position with respect to the sheath streams. We demonstrate the separation of the sample stream from the contiguous sheath streams and the recycling of the sheath fluid using the reversibility of laminar flow. Polystyrene microspheres and fluorescent dye were used to quantify the performance of the unsheathing process. We found that the maximum numbers of microspheres and all of the fluorescent dye were recaptured at sheath recycling levels recycle the sheath fluid for long-term unattended operation. PMID:20480064

  16. Use of guiding sheaths in peroral fluoroscopic gastroduodenal stent placement

    International Nuclear Information System (INIS)

    Bae, Jae-Ik; Shin, Ji Hoon; Song, Ho-Young; Yoon, Chang Jin; Nam, Deok Ho; Choi, Won-Chan; Lim, Jin-Oh

    2005-01-01

    Our purpose was to assess the safety and usefulness of guiding sheaths in peroral fluoroscopic gastroduodenal stent placement. Two types of guiding sheath were made from straight polytetrafluoroethylene tubes. Type A was 80 cm in length, 4 mm in outer diameter and 3 mm in inner diameter. Type B was 70 cm in length, 6 mm in outer diameter and 5 mm in inner diameter. The type A sheath was used in 18 patients in whom a catheter-guide wire combination failed to pass through a stricture. The type B sheath was used in 22 patients in whom a stent delivery system failed to pass through the stricture due to loop formation within the gastric lumen. The overall success rate for guiding a catheter-guide wire through a stricture after using the type A sheath was 89%. The overall success rate for passing a stent delivery system through a stricture after using the type B sheath was 100%. All procedures were tolerated by the patients without any significant complications. The guiding sheaths were safe and useful in peroral fluoroscopic gastroduodenal stent placement. (orig.)

  17. Abiotic Deposition of Fe Complexes onto Leptothrix Sheaths

    Science.gov (United States)

    Kunoh, Tatsuki; Hashimoto, Hideki; McFarlane, Ian R.; Hayashi, Naoaki; Suzuki, Tomoko; Taketa, Eisuke; Tamura, Katsunori; Takano, Mikio; El-Naggar, Mohamed Y.; Kunoh, Hitoshi; Takada, Jun

    2016-01-01

    Bacteria classified in species of the genus Leptothrix produce extracellular, microtubular, Fe-encrusted sheaths. The encrustation has been previously linked to bacterial Fe oxidases, which oxidize Fe(II) to Fe(III) and/or active groups of bacterial exopolymers within sheaths to attract and bind aqueous-phase inorganics. When L. cholodnii SP-6 cells were cultured in media amended with high Fe(II) concentrations, Fe(III) precipitates visibly formed immediately after addition of Fe(II) to the medium, suggesting prompt abiotic oxidation of Fe(II) to Fe(III). Intriguingly, these precipitates were deposited onto the sheath surface of bacterial cells as the population was actively growing. When Fe(III) was added to the medium, similar precipitates formed in the medium first and were abiotically deposited onto the sheath surfaces. The precipitates in the Fe(II) medium were composed of assemblies of globular, amorphous particles (ca. 50 nm diameter), while those in the Fe(III) medium were composed of large, aggregated particles (≥3 µm diameter) with a similar amorphous structure. These precipitates also adhered to cell-free sheaths. We thus concluded that direct abiotic deposition of Fe complexes onto the sheath surface occurs independently of cellular activity in liquid media containing Fe salts, although it remains unclear how this deposition is associated with the previously proposed mechanisms (oxidation enzyme- and/or active group of organic components-involved) of Fe encrustation of the Leptothrix sheaths. PMID:27271677

  18. Abiotic Deposition of Fe Complexes onto Leptothrix Sheaths

    Directory of Open Access Journals (Sweden)

    Tatsuki Kunoh

    2016-06-01

    Full Text Available Bacteria classified in species of the genus Leptothrix produce extracellular, microtubular, Fe-encrusted sheaths. The encrustation has been previously linked to bacterial Fe oxidases, which oxidize Fe(II to Fe(III and/or active groups of bacterial exopolymers within sheaths to attract and bind aqueous-phase inorganics. When L. cholodnii SP-6 cells were cultured in media amended with high Fe(II concentrations, Fe(III precipitates visibly formed immediately after addition of Fe(II to the medium, suggesting prompt abiotic oxidation of Fe(II to Fe(III. Intriguingly, these precipitates were deposited onto the sheath surface of bacterial cells as the population was actively growing. When Fe(III was added to the medium, similar precipitates formed in the medium first and were abiotically deposited onto the sheath surfaces. The precipitates in the Fe(II medium were composed of assemblies of globular, amorphous particles (ca. 50 nm diameter, while those in the Fe(III medium were composed of large, aggregated particles (≥3 µm diameter with a similar amorphous structure. These precipitates also adhered to cell-free sheaths. We thus concluded that direct abiotic deposition of Fe complexes onto the sheath surface occurs independently of cellular activity in liquid media containing Fe salts, although it remains unclear how this deposition is associated with the previously proposed mechanisms (oxidation enzyme- and/or active group of organic components-involved of Fe encrustation of the Leptothrix sheaths.

  19. Pulsed klystrons with feedback controlled mod-anode modulators

    Energy Technology Data Exchange (ETDEWEB)

    Reass, William A [Los Alamos National Laboratory; Baca, David M [Los Alamos National Laboratory; Jerry, Davis L [Los Alamos National Laboratory; Rees, Daniel E [Los Alamos National Laboratory

    2009-01-01

    This paper describes a fast rise and fall, totem-pole mod-anode modulators for klystron application. Details of these systems as recently installed utilizing a beam switch tube ''on-deck'' and a planar triode ''off-deck'' in a grid-catch feedback regulated configuration will be provided. The grid-catch configuration regulates the klystron mod-anode voltage at a specified set-point during switching as well as providing a control mechanism that flat-top regulates the klystron beam current during the pulse. This flat-topped klystron beam current is maintained while the capacitor bank droops. In addition, we will review more modern on-deck designs using a high gain, high voltage planar triode as a regulating and switching element. These designs are being developed, tested, and implemented for the Los Alamos Neutron Science Center (LANSCE) accelerator refurbishment project, ''LANSCE-R''. An advantage of the planar triode is that the tube can be directly operated with solid state linear components and provides for a very compact design. The tubes are inexpensive compared to stacked semiconductor switching assemblies and also provide a linear control capability. Details of these designs are provided as well as operational and developmental results.

  20. Experimental test of models of radio-frequency plasma sheaths

    International Nuclear Information System (INIS)

    Sobolewski, M.A.

    1997-01-01

    The ion current and sheath impedance were measured at the radio-frequency-powered electrode of an asymmetric, capacitively coupled plasma reactor, for discharges in argon at 1.33 endash 133 Pa. The measurements were used to test the models of the radio frequency sheath derived by Lieberman [IEEE Trans. Plasma Sci. 17, 338 (1989)] and Godyak and Sternberg [Phys. Rev. A 42, 2299 (1990)], and establish the range of pressure and sheath voltage in which they are valid. copyright 1997 American Institute of Physics

  1. Ultrasonographic findings of pilar sheath acanthoma: A case report

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Dong Joo; Lee, Sun Joo; Kim, Seong Jin [Inje University College of Medicine, Busan Paik Hospital, Busan (Korea, Republic of)

    2017-08-15

    Pilar sheath acanthoma is a rare benign follicular hamartoma that presents with a central sinus containing keratinous material and is lined by epithelium. It typically occurs on the face, especially on the upper lip and forehead. In our case, the ultrasound (US) feature of pilar sheath acanthoma revealed a well-defined, oval hypoechoic nodule with hypoechoic capping within the dermis over the medial aspect of the calf. To the best of our knowledge, despite many reports on the clinicopathological aspects of pilar sheath acanthoma, this entity has not been well described in the radiologic literature, and US findings have not been documented.

  2. Bistable switching in supercritical n+-n-n+GaAs transferred electron devices

    DEFF Research Database (Denmark)

    Jøndrup, Peter; Jeppesen, Palle; Jeppson, Bert

    1976-01-01

    Bistable switching in supercritically doped n+-n-n+GaAs transferred electron devices (TED's) is investigated experimentally and interpreted in computer simulations, for which details of the computer program are given. Three switching modes all leading to stable anode domains are discussed, namely...

  3. Mesoporous Silicon-Based Anodes

    Science.gov (United States)

    Peramunage, Dharmasena

    2015-01-01

    For high-capacity, high-performance lithium-ion batteries. A new high-capacity anode composite based on mesoporous silicon is being developed. With a structure that resembles a pseudo one-dimensional phase, the active anode material will accommodate significant volume changes expected upon alloying and dealloying with lithium (Li).

  4. Adaptable silicon-carbon nanocables sandwiched between reduced graphene oxide sheets as lithium ion battery anodes.

    Science.gov (United States)

    Wang, Bin; Li, Xianglong; Zhang, Xianfeng; Luo, Bin; Jin, Meihua; Liang, Minghui; Dayeh, Shadi A; Picraux, S T; Zhi, Linjie

    2013-02-26

    Silicon has been touted as one of the most promising anode materials for next generation lithium ion batteries. Yet, how to build energetic silicon-based electrode architectures by addressing the structural and interfacial stability issues facing silicon anodes still remains a big challenge. Here, we develop a novel kind of self-supporting binder-free silicon-based anodes via the encapsulation of silicon nanowires (SiNWs) with dual adaptable apparels (overlapped graphene (G) sheaths and reduced graphene oxide (RGO) overcoats). In the resulted architecture (namely, SiNW@G@RGO), the overlapped graphene sheets, as adaptable but sealed sheaths, prevent the direct exposure of encapsulated silicon to the electrolyte and enable the structural and interfacial stabilization of silicon nanowires. Meanwhile, the flexible and conductive RGO overcoats accommodate the volume change of embedded SiNW@G nanocables and thus maintain the structural and electrical integrity of the SiNW@G@RGO. As a result, the SiNW@G@RGO electrodes exhibit high reversible specific capacity of 1600 mAh g⁻¹ at 2.1 A g⁻¹, 80% capacity retention after 100 cycles, and superior rate capability (500 mAh g⁻¹ at 8.4 A g⁻¹) on the basis of the total electrode weight.

  5. Anodic Concentration Polarization in SOFCs

    Energy Technology Data Exchange (ETDEWEB)

    Williford, Rick E.; Chick, Lawrence A.; Maupin, Gary D.; Simner, Steve P.; Stevenson, Jeffry W.; Khaleel, Mohammad A.; Wachsman, ED, et al

    2003-08-01

    Concentration polarization is important because it determines the maximum power output of a solid oxide fuel cell (SOFC) at high fuel utilization. Anodic concentration polarization occurs when the demand for reactants exceeds the capacity of the porous ceramic anode to supply them by gas diffusion mechanisms. High tortuosities (bulk diffusion resistances) are often assumed to explain this behavior. However, recent experiments show that anodic concentration polarization originates in the immediate vicinity of the reactive triple phase boundary (TPB) sites near the anode/electrolyte interface. A model is proposed to describe how concentration polarization is controlled by two localized phenomena: competitive adsorption of reactants in areas adjacent to the reactive TPB sites, followed by relatively slow surface diffusion to the reactive sites. Results suggest that future SOFC design improvements should focus on optimization of the reactive area, adsorption, and surface diffusion at the anode/electrolyte interface.

  6. Bilateral giant cell tumor of tendon sheath of tendoachilles

    Directory of Open Access Journals (Sweden)

    Soma Datta

    2014-01-01

    Full Text Available Giant cell tumor of tendon sheath arises from the synovium of tendon sheaths, joints, or bursae, mostly affects adults between 30 and 50 years of age, and is slightly more common in females. We report the case of a 32-years-old male presenting with pain in both ankles without any history of trauma. On clinical examination, tenderness on both tendoachilles and local thickening were observed. Ultrasonography showed thickening of local tendinous area with increase in anteroposterior diameter, and Doppler demonstrated increased flow in peritendinous area. MRI findings showed that most of the tumor had intermediate signal intensity and portions of the tumor had low signal intensity. Fine needle aspiration cytology confirmed the diagnosis of giant cell tumor of tendon sheath. Excision biopsy was done with no recurrence on five month follow-up. Review of literature did not reveal any similar result; so, bilateral giant cell tumor of tendon sheath of tendoachilles is a rare presentation.

  7. Zircaloy sheathed thermocouples for PWR fuel rod temperature measurements

    International Nuclear Information System (INIS)

    Anderson, J.V.; Wesley, R.D.; Wilkins, S.C.

    1979-01-01

    Small diameter zircaloy sheathed thermocouples have been developed by EG and G Idaho, Inc., at the Idaho National Engineering Laboratory. Surface mounted thermocouples were developed to measure the temperature of zircaloy clad fuel rods used in the Thermal Fuels Behavior Program (TFBP), and embedded thermocouples were developed for use by the Loss-of-Fluid Test (LOFT) Program for support tests using zircaloy clad electrically heated nuclear fuel rod simulators. The first objective of this developmental effort was to produce zircaloy sheathed thermocouples to replace titanium sheathed thermocouples and thereby eliminate the long-term corrosion of the titanium-to-zircaloy attachment weld. The second objective was to reduce the sheath diameter to obtain faster thermal response and minimize cladding temperature disturbance due to thermocouple attachment

  8. Machining a conical inner surface of a sheath

    International Nuclear Information System (INIS)

    Lebiez, Y.; Salom, J.; La Joie, D.

    1993-01-01

    A machine tool is claimed for machining sheaths too long for a lathe. It comprises two concentric shafts, one rotating, the other sliding. The rotating shaft bear an oblique sliding tool-holder parallel to the machining direction

  9. Measure Guideline: Guidance on Taped Insulating Sheathing Drainage Planes

    Energy Technology Data Exchange (ETDEWEB)

    Grin, A. [Building Science Corporation, Somerville, MA (United States); Lstiburek, J. [Building Science Corporation, Somerville, MA (United States)

    2014-09-01

    The goal of this research is to provide durable and long-term water management solutions using exterior insulating sheathing as part of the water management system. It is possible to tape or seal the joints in insulating sheathing to create a drainage plane and even an air control layer. There exists the material durability component of the tape as well as the system durability component being the taped insulating sheathing as the drainage plane. This measure guideline provides best practice and product recommendations from the interviewed contractors and homebuilders who collectively have a vast amount of experience. Three significant issues were discussed with the group, which are required to make taped insulating sheathing a simple, long-term, and durable drainage plane: horizontal joints should be limited or eliminated wherever possible; where a horizontal joint exists use superior materials; and frequent installation inspection and regular trade training are required to maintain proper installation.

  10. Axial sheath dynamics in a plasma focus

    International Nuclear Information System (INIS)

    Soliman, H.M.; El-Khalafawy, T.A.; Masoud, M.M.

    1990-01-01

    This paper presents the result of investigation with a 10 kJ Mather type plasma focus. It is operated in hydrogen gas at ambient pressure of 0.15--1 torr and charging voltage of 8--11 kV. Radial distribution of the current sheath density with axial distance has been estimated. Plasma rotation in the expansion chamber in the absence of external magnetic field has been detected. A plasma flare from the plasma focus region propagating in the radial direction has been observed. Streak photography shows two plasma streams flowing simultaneously out of the muzzle. The mean energy of the electron beam ejected from the pinch region of the focused plasma, was measured by retarding field analyzer to be 0.32 keV. The electron temperature of the plasma focus at peak compression was determined by measuring the X-ray intensity as a function of absorber thickness at a distance of 62 cm from the focus. The electron temperature has been found to 3 keV

  11. Properties of leaves particleboard for sheathing application

    Science.gov (United States)

    Nuryawan, Arif; Rahmawaty

    2018-03-01

    Manufacturing particleboard (PB) made of leaves was carried out to make non-structural building components, such as insulation, partition, wall, and sheathing. Raw materials used dry leaves originated from plantation (palm oil leaves) and forest plantation (magahony leaves). The adhesive used was interior type thermosetting commercial resins, namely 10% urea-formaldehyde (UF) based on oven dry leaves. Hardener used for UF resin was 1% and 3% ammonium chloride (NH4Cl) 20% (w/w), respectively. Technically, the target density of PB was 0.8 g/cm3 with the dimension’s size of (250 x 250 x 10) mm3. The pressure, temperature, and time of pressing of the hot press were 25 kgf/cm2, 120C, and 10 minutes, respectively. After conditioning for one week, the PB then was evaluated their physical and mechanical properties according to Japanese Industrial Standard (JIS) A 5908 (2003). Results of this work showed: 1) Both types of PB (palm oil and mahagony leaves) were feasible to be produced for non-structural applications; 2) Addition of hardener enhanced the physical and mechanical properties of PB; 3) It was recommended to enhance the performance of the PB by manipulation of the raw materials and the design.

  12. An unusual radiological presentation of optic nerve sheath meningiom

    Directory of Open Access Journals (Sweden)

    Chameen Samarawickrama

    2016-04-01

    Full Text Available Our report describes an unusual radiological presentation of optic nerve sheath meningioma. The classic radiological appearance of optic nerve thickening with enhancement and calcification within the tumor was not seen; instead, an elongating gadolinium enhancing band-like area adjacent to the superomedial aspect of the left optic nerve sheath was identified. The diagnosis was confirmed on histopathology. Our report adds to the spectrum of presentations of this relatively common clinical entity.

  13. Sheath and plasma parameters in a magnetized plasma system

    Indian Academy of Sciences (India)

    ions forming the sheath across the grid, are moving with a velocity equal to or greater than the ion acoustic velocity ´c×µ, in order to satisfy the minimum Bohm sheath criterion. For a fixed V , when more and more magnetic field is applied, gyro radius of both ions and electrons are reduced gradually. But at the same time gyro ...

  14. Contrast material filling of the peroneal tendon sheath

    International Nuclear Information System (INIS)

    Zadravecz, Gy.; Grexa, E.

    1981-01-01

    In case of complaints after fracture of the calcaneus the common sheath of the peroneus tendons was filled up with contrast material. The tendon sheath was punctured Oehind the external ankle. The three-directional radiograms clearly showed the dislocation and compression of the tendons, caused by the exostosis of the calcaneus. The concomitant tendovaginitis caused the complaints. This alteration was observed in 11% of all the calcaneus fractures. (L.E.)

  15. Studies of irradiated zircaloy fuel sheathing using XPS

    International Nuclear Information System (INIS)

    Chan, P.K.; Irving, K.G.; Hocking, W.H.; Duclos, A.M.; Gerwing, A.F.

    1995-01-01

    The preliminary results reported here support the hypothesis that CANLUB graphite coating reduces the rate at which oxygen can react with fuel sheathing. X-ray photoelectron spectroscopic (XPS) characterization of Zircaloy sheathing obtained from extended-burnup Bruce-type elements (BDL-406-XY (555 MW.h/kgU) and BDL-406-AAH (731 MW.h/kgU)) irradiated in NRU indicates that CANLUB may reduce fuel sheath oxidation, and hence that fission-liberated oxygen may remain in the fuel. Chemical shifts in the Zr 3d spectra suggest that a stoichiometric (ZrO 2 ) oxide film was formed only on Zircaloy in direct contact with fuel. Particulate fuel adhering to the sheath was also determined to be systematically more oxidized on surfaces with CANLUB than on those without it. The unique association of tin on sheathing specimens with the non-CANLUB-coated specimens might also suggest that the tin had segregated from the sheathing. It must be emphasized that further experiments are required to better define the effect of CANLUB on fuel oxidation. (author). 14 refs., 1 tab., 3 figs

  16. Multimodal imaging in neurofibromatosis type 1-associated nerve sheath tumors

    International Nuclear Information System (INIS)

    Salamon, J.; Adam, G.; Mautner, V.F.; Derlin, T.

    2015-01-01

    Neurofibromatosis type 1 (NF1) is a neurogenetic disorder. Individuals with NF1 may develop a variety of benign and malignant tumors of which peripheral nerve sheath tumors represent the most frequent entity. Plexiform neurofibromas may demonstrate a locally destructive growth pattern, may cause severe symptoms and may undergo malignant transformation into malignant peripheral nerve sheath tumors (MPNSTs). Whole-body magnetic resonance imaging (MRI) represents the reference standard for detection of soft tissue tumors in NF1. It allows for identification of individuals with plexiform neurofibromas, for assessment of local tumor extent, and for evaluation of whole-body tumor burden on T2-weighted imaging. Multiparametric MRI may provide a comprehensive characterization of different tissue properties of peripheral nerve sheath tumors, and may identify parameters associated with malignant transformation. Due to the absence of any radiation exposure, whole-body MRI may be used for serial follow-up of individuals with plexiform neurofibromas. 18 F-fluorodeoxyglucose positron-emission-tomography (FDG PET/CT) allows a highly sensitive and specific detection of MPNST, and should be used in case of potential malignant transformation of a peripheral nerve sheath tumor. PET/CT provides a sensitive whole-body tumor staging. The use of contrast-enhanced CT for diagnosis of peripheral nerve sheath tumors is limited to special indications. To obtain the most precise readings, optimized examination protocols and dedicated radiologists and nuclear medicine physicians familiar with the complex and variable morphologies of peripheral nerve sheath tumors are required.

  17. Medical image of the week: saber sheath trachea

    Directory of Open Access Journals (Sweden)

    Low S-W

    2017-06-01

    Full Text Available No abstract available. Article truncated after 150 words. A 79-year-old man with chronic obstructive pulmonary disease (COPD and an active smoker was transferred for evaluation of tracheal narrowing and concerns of malignant external compression versus tracheobronchomalacia for possible stenting. The patient underwent both chest computed tomography (Figure 1 and bronchoscopy (Figure 2 that confirmed the diagnosis of saber-sheath trachea and ruled out external compression. The airway was still adequately patent during inspiration and expiration with no clear dynamic collapse. Saber-sheath trachea is commonly described as intra-thoracic coronal narrowing and sagittal widening of the trachea (like a sword sheath. Repetitive cartilaginous injury from excessive coughing and elevated intra-thoracic pressure causes degeneration and calcification of the trachea cartilage, leading to remodeling and bending of the tracheal cartilage (1. Presence of saber-sheath trachea is highly associated with obstructive lung disease, which is present in our patient (2. There is no known specific treatment for saber-sheath trachea, however if patient with saber-sheath

  18. Expanding refractory rectus sheath hematoma: a therapeutic dilemma.

    Science.gov (United States)

    Tseng, Guo-Shiang; Liau, Guo-Shiou; Shyu, Hann-Yeh; Chu, Shi-Jye; Ko, Fu-Chang; Wu, Kuo-An

    2012-01-01

    Rectus sheath hematoma is an uncommon but well-described complication of a tussive paroxysm. It is an accumulation of blood within the sheath of the rectus abdominis secondary to disruption of the epigastric vessels or the rectus muscle and is often misdiagnosed as acute abdomen. Increases in the number of elderly patients and the use of therapeutic anticoagulation may increase the prevalence and severity of rectus sheath hematomas encountered in clinical practice. Expanding rectus sheath hematomas are occasionally refractory to conservative treatment and may require hemostatic intervention. Here, we describe the case of an 87-year-old woman who presented with two separate rectus sheath hematomas that were precipitated by a paroxysm of coughing. Repeated computed tomography showed two separate expanding rectus sheath hematomas, which were not accompanied by obvious contrast extravasation on angiography. Empiric left inferior epigastric artery embolization resulted in rapid hemodynamic stabilization, and the hematomas shrank gradually. Early empiric transcatheter arterial embolization may be appropriate for patients who are poor surgical candidates and have enlarging hematomas that are refractory to conservative treatment.

  19. Contact materials for nanowire devices and nanoelectromechanical switches

    KAUST Repository

    Hussain, Muhammad Mustafa

    2011-02-01

    The impact of contact materials on the performance of nanostructured devices is expected to be signifi cant. This is especially true since size scaling can increase the contact resistance and induce many unseen phenomenon and reactions that greatly impact device performance. Nanowire and nanoelectromechanical switches are two emerging nanoelectronic devices. Nanowires provide a unique opportunity to control the property of a material at an ultra-scaled dimension, whereas a nanoelectromechanical switch presents zero power consumption in its off state, as it is physically detached from the sensor anode. In this article, we specifi cally discuss contact material issues related to nanowire devices and nanoelectromechanical switches.

  20. Nano structural anodes for radiation detectors

    Science.gov (United States)

    Cordaro, Joseph V.; Serkiz, Steven M.; McWhorter, Christopher S.; Sexton, Lindsay T.; Retterer, Scott T.

    2015-07-07

    Anodes for proportional radiation counters and a process of making the anodes is provided. The nano-sized anodes when present within an anode array provide: significantly higher detection efficiencies due to the inherently higher electric field, are amenable to miniaturization, have low power requirements, and exhibit a small electromagnetic field signal. The nano-sized anodes with the incorporation of neutron absorbing elements (e.g., .sup.10B) allow the use of neutron detectors that do not use .sup.3He.

  1. Switched on!

    CERN Multimedia

    2008-01-01

    Like a star arriving on stage, impatiently followed by each member of CERN personnel and by millions of eyes around the world, the first beam of protons has circulated in the LHC. After years in the making and months of increasing anticipation, today the work of hundreds of people has borne fruit. WELL DONE to all! Successfully steered around the 27 kilometres of the world’s most powerful particle accelerator at 10:28 this morning, this first beam of protons circulating in the ring marks a key moment in the transition from over two decades of preparation to a new era of scientific discovery. "It’s a fantastic moment," said the LHC project leader Lyn Evans, "we can now look forward to a new era of understanding about the origins and evolution of the universe". Starting up a major new particle accelerator takes much more than flipping a switch. Thousands of individual elements have to work in harmony, timings have to be synchronize...

  2. Monitoring of epitaxial graphene anodization

    International Nuclear Information System (INIS)

    Vagin, Mikhail Yu.; Sekretaryova, Alina N.; Ivanov, Ivan G.; Håkansson, Anna; Iakimov, Tihomir; Syväjärvi, Mikael; Yakimova, Rositsa; Lundström, Ingemar; Eriksson, Mats

    2017-01-01

    Anodization of a graphene monolayer on silicon carbide was monitored with electrochemical impedance spectroscopy. Structural and functional changes of the material were observed by Raman spectroscopy and voltammetry. A 21 fold increase of the specific capacitance of graphene was observed during the anodization. An electrochemical kinetic study of the Fe(CN) 6 3−/4− redox couple showed a slow irreversible redox process at the pristine graphene, but after anodization the reaction rate increased by several orders of magnitude. On the other hand, the Ru(NH 3 ) 6 3+/2+ redox couple proved to be insensitive to the activation process. The results of the electron transfer kinetics correlate well with capacitance measurements. The Raman mapping results suggest that the increased specific capacitance of the anodized sample is likely due to a substantial increase of electron doping, induced by defect formation, in the monolayer upon anodization. The doping concentration increased from less than 1 × 10 13 of the pristine graphene to 4–8 × 10 13 of the anodized graphene.

  3. [The history of the contraceptive sheath].

    Science.gov (United States)

    Guyotjeannin, C

    1984-06-01

    The condom, effective in preventing both pregnancy and venereal disease, had a limited role until the 19th century, when its use spread through all social strata. The 1st condoms may have been linen sheaths designed to protect against syphilis. A 16th century Neapolitan doctor provided a recipe for an antiseptic preparation to be applied for 4-5 hourrs, but after intercourse had occurred. A physician to Louis XV mentioned the condom in a book published in 1736, and in 1770 the condom was again described without being named. 4 yeears later it was again described and called the condom or English redingote. Later it was mentioned by the Marques de Sade, who alluded to its contraceptive effect. In the early 19th century, condoms made of sheep entrails were mentioned. Descriptions of the preparation of 3 grades of condom, regular, fine, and superfine, were later found. The discovery of the process of vulcanization of rubber in 1839 made possible more solid, marketable, and usable latex condoms. The condom apparently began to be used in the late 17th or early 18th century. Some authors state that it was invented by a Dr. Condom or Conton, a physician or knight in the court of Charls II of England. Othrs suggested that it was named after the city of Condom in Gascony or derived from a foreign word. The antivenereal disease qualities of condoms were described by Casanova and Gustave Flaubert, and other references to them may be found in the literature. Later the contraceptive use of the condom became progressively more common, beginning in the wealthier classes and spreading to the rural and lower classes perhaps by the later 18th century. The diffusion of contraception during the 19th century was cited as the cause of th slow decline in illegitimacy rates starting at the end of the century. The Church condemned the use of condoms for contraception, but the medical profession took a less hostile view due to their health function. At the present time, condoms are widely

  4. An investigation of tendon sheathing filler migration into concrete

    Energy Technology Data Exchange (ETDEWEB)

    Naus, D.J.; Oland, C.B. [Oak Ridge National Lab., TN (United States)

    1998-03-01

    During some of the inspections at nuclear power plants with prestressed concrete containments, it was observed that the containments has experienced leakage of the tendon sheathing filler (i.e., streaks). The objective of this activity was to provide an indication of the extent of tendon sheathing filler leakage into the concrete and its affects on concrete properties. Literature was reviewed and concrete core samples were obtained from the Trojan Nuclear Plant and tested. The literature primarily addressed effects of crude or lubricating oils that are known to cause concrete damage. However, these materials have significantly different characteristics relative to the materials used as tendon sheathing fillers. Examination and testing of the concrete cores indicated that the appearance of tendon sheathing filler on the concrete surface was due to leakage from the conduits and its subsequent migration through cracks that were present. Migration of the tendon sheathing filler was confined to the cracks and there was no perceptible movement into the concrete. Results of compressive strength testing indicated that the concrete quality was consistent in the containment and that the strength had increased over 40% in 25.4 years relative to the average compressive strength at 28-days age.

  5. The influence of collisions on the plasma sheath transition

    International Nuclear Information System (INIS)

    Riemann, K.

    1997-01-01

    In the asymptotic limit λ D /λ→0 (where λ D is the electron Debye length and λ represents the ion mean free path) the boundary layer of a collision dominated plasma is split up in a collision free planar sheath (scale λ D ) and a quasi-neutral presheath (scale λ). The open-quotes sheath edgeclose quotes separating the presheath and the sheath is defined by the Bohm criterion. To clear up controversial statements on the validity of the plasma sheath concept and on the role of the Bohm criterion for finite values of λ D /λ, a simple fluid model of the ions is used to account for collisions and for space charges in the boundary layer. It is shown that the asymptotic solution on an open-quotes intermediate scaleclose quotes (scale length λ 1/5 λ D 4/5 ) is suitable to match the presheath and sheath solutions smoothly and to construct a convenient approximation for small but finite λ D /λ. The intermediate scale, again, is closely related to the Bohm criterion. Various attempts to derive a open-quotes generalizedclose quotes Bohm criterion accounting for collisions are inconsistent. copyright 1997 American Institute of Physics

  6. An investigation of tendon sheathing filler migration into concrete

    International Nuclear Information System (INIS)

    Naus, D.J.; Oland, C.B.

    1998-03-01

    During some of the inspections at nuclear power plants with prestressed concrete containments, it was observed that the containments has experienced leakage of the tendon sheathing filler (i.e., streaks). The objective of this activity was to provide an indication of the extent of tendon sheathing filler leakage into the concrete and its affects on concrete properties. Literature was reviewed and concrete core samples were obtained from the Trojan Nuclear Plant and tested. The literature primarily addressed effects of crude or lubricating oils that are known to cause concrete damage. However, these materials have significantly different characteristics relative to the materials used as tendon sheathing fillers. Examination and testing of the concrete cores indicated that the appearance of tendon sheathing filler on the concrete surface was due to leakage from the conduits and its subsequent migration through cracks that were present. Migration of the tendon sheathing filler was confined to the cracks and there was no perceptible movement into the concrete. Results of compressive strength testing indicated that the concrete quality was consistent in the containment and that the strength had increased over 40% in 25.4 years relative to the average compressive strength at 28-days age

  7. Sheath-accumulating Propagation of Interplanetary Coronal Mass Ejection

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Takuya; Shibata, Kazunari, E-mail: takahasi@kusastro.kyoto-u.ac.jp [Kwasan and Hida Observatories, Kyoto University, Yamashina, Kyoto 607–8471 (Japan)

    2017-03-10

    Fast interplanetary coronal mass ejections (ICMEs) are the drivers of strong space weather storms such as solar energetic particle events and geomagnetic storms. The connection between the space-weather-impacting solar wind disturbances associated with fast ICMEs at Earth and the characteristics of causative energetic CMEs observed near the Sun is a key question in the study of space weather storms, as well as in the development of practical space weather prediction. Such shock-driving fast ICMEs usually expand at supersonic speeds during the propagation, resulting in the continuous accumulation of shocked sheath plasma ahead. In this paper, we propose a “sheath-accumulating propagation” (SAP) model that describes the coevolution of the interplanetary sheath and decelerating ICME ejecta by taking into account the process of upstream solar wind plasma accumulation within the sheath region. Based on the SAP model, we discuss (1) ICME deceleration characteristics; (2) the fundamental condition for fast ICMEs at Earth; (3) the thickness of interplanetary sheaths; (4) arrival time prediction; and (5) the super-intense geomagnetic storms associated with huge solar flares. We quantitatively show that not only the speed but also the mass of the CME are crucial for discussing the above five points. The similarities and differences between the SAP model, the drag-based model, and the“snow-plow” model proposed by Tappin are also discussed.

  8. Ontogeny of the sheathing leaf base in maize (Zea mays).

    Science.gov (United States)

    Johnston, Robyn; Leiboff, Samuel; Scanlon, Michael J

    2015-01-01

    Leaves develop from the shoot apical meristem (SAM) via recruitment of leaf founder cells. Unlike eudicots, most monocot leaves display parallel venation and sheathing bases wherein the margins overlap the stem. Here we utilized computed tomography (CT) imaging, localization of PIN-FORMED1 (PIN1) auxin transport proteins, and in situ hybridization of leaf developmental transcripts to analyze the ontogeny of monocot leaf morphology in maize (Zea mays). CT imaging of whole-mounted shoot apices illustrates the plastochron-specific stages during initiation of the basal sheath margins from the tubular disc of insertion (DOI). PIN1 localizations identify basipetal auxin transport in the SAM L1 layer at the site of leaf initiation, a process that continues reiteratively during later recruitment of lateral leaf domains. Refinement of these auxin transport domains results in multiple, parallel provascular strands within the initiating primordium. By contrast, auxin is transported from the L2 toward the L1 at the developing margins of the leaf sheath. Transcripts involved in organ boundary formation and dorsiventral patterning accumulate within the DOI, preceding the outgrowth of the overlapping margins of the sheathing leaf base. We suggest a model wherein sheathing bases and parallel veins are both patterned via the extended recruitment of lateral maize leaf domains from the SAM. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

  9. Coronal mass ejections and their sheath regions in interplanetary space

    Directory of Open Access Journals (Sweden)

    Emilia Kilpua

    2017-11-01

    Full Text Available Abstract Interplanetary coronal mass ejections (ICMEs are large-scale heliospheric transients that originate from the Sun. When an ICME is sufficiently faster than the preceding solar wind, a shock wave develops ahead of the ICME. The turbulent region between the shock and the ICME is called the sheath region. ICMEs and their sheaths and shocks are all interesting structures from the fundamental plasma physics viewpoint. They are also key drivers of space weather disturbances in the heliosphere and planetary environments. ICME-driven shock waves can accelerate charged particles to high energies. Sheaths and ICMEs drive practically all intense geospace storms at the Earth, and they can also affect dramatically the planetary radiation environments and atmospheres. This review focuses on the current understanding of observational signatures and properties of ICMEs and the associated sheath regions based on five decades of studies. In addition, we discuss modelling of ICMEs and many fundamental outstanding questions on their origin, evolution and effects, largely due to the limitations of single spacecraft observations of these macro-scale structures. We also present current understanding of space weather consequences of these large-scale solar wind structures, including effects at the other Solar System planets and exoplanets. We specially emphasize the different origin, properties and consequences of the sheaths and ICMEs.

  10. Structural Conservation of the Myoviridae Phage Tail Sheath Protein Fold

    Energy Technology Data Exchange (ETDEWEB)

    Aksyuk, Anastasia A.; Kurochkina, Lidia P.; Fokine, Andrei; Forouhar, Farhad; Mesyanzhinov, Vadim V.; Tong, Liang; Rossmann, Michael G. (SOIBC); (Purdue); (Columbia)

    2012-02-21

    Bacteriophage phiKZ is a giant phage that infects Pseudomonas aeruginosa, a human pathogen. The phiKZ virion consists of a 1450 {angstrom} diameter icosahedral head and a 2000 {angstrom}-long contractile tail. The structure of the whole virus was previously reported, showing that its tail organization in the extended state is similar to the well-studied Myovirus bacteriophage T4 tail. The crystal structure of a tail sheath protein fragment of phiKZ was determined to 2.4 {angstrom} resolution. Furthermore, crystal structures of two prophage tail sheath proteins were determined to 1.9 and 3.3 {angstrom} resolution. Despite low sequence identity between these proteins, all of these structures have a similar fold. The crystal structure of the phiKZ tail sheath protein has been fitted into cryo-electron-microscopy reconstructions of the extended tail sheath and of a polysheath. The structural rearrangement of the phiKZ tail sheath contraction was found to be similar to that of phage T4.

  11. Formation and disruption of current paths of anodic porous alumina films by conducting atomic force microscopy

    International Nuclear Information System (INIS)

    Oyoshi, K.; Nigo, S.; Inoue, J.; Sakai, O.; Kitazawa, H.; Kido, G.

    2010-01-01

    Anodic porous alumina (APA) films have a honeycomb cell structure of pores and a voltage-induced bi-stable switching effect. We have applied conducting atomic force microscopy (CAFM) as a method to form and to disrupt current paths in the APA films. A bi-polar switching operation was confirmed. We have firstly observed terminals of current paths as spots or areas typically on the center of the triangle formed by three pores. In addition, though a part of the current path showed repetitive switching, most of them were not observed again at the same position after one cycle of switching operations in the present experiments. This suggests that a part of alumina structure and/or composition along the current paths is modified during the switching operations.

  12. Rupture of the biceps brachii tendon sheath in two dogs.

    Science.gov (United States)

    Innes, J F; Brown, G

    2004-01-01

    Rupture of the biceps brachii tendon sheath was diagnosed in two dogs which were presented with chronic thoracic limb lameness. In each case, diagnosis was achieved by positive contrast arthrography, which revealed obvious leakage of contrast agent from the distal portion of the tendon sheath. Arthroscopy was performed in each affected shoulder joint and no other significant lesions were found. In one dog, concomitant bicipital tendinopathy was confirmed by histopathology. Both dogs were treated by bicipital tendon transposition, and tenodesis and both showed improvement in the degree of lameness following surgery. Tearing of the biceps brachii tendon sheath has not been reported previously but should be included in the differential diagnosis for shoulder lameness in the adult dog.

  13. Rectus sheath hematoma of the abdomen. Case report.

    Science.gov (United States)

    Villena-Tovar, José Francisco

    2010-01-01

    Rectus sheath hematoma in the vast number of cases is due to an inferior epigastric artery tear occasionally due to trauma (not considered serious) or alterations in coagulation or use of anticoagulant therapy. It is an unlikely and difficult to diagnose pathology. We present the case of a 61-year-old female patient. The patient presented in emergency service with sudden abdominal pain caused by coughing as a result of an upper respiratory tract infection. The culmination was a spontaneous rectus sheath hematoma. Rectus sheath hematoma is a diagnosis to consider in a previously asymptomatic patient who presents with clinical features of acute pain and appearance of increase of volume in the abdominal wall involving the rectus muscles.

  14. Anomalous Capacitive Sheath with Deep Radio Frequency Electric Field Penetration

    International Nuclear Information System (INIS)

    Kaganovich, Igor D.

    2002-01-01

    A novel nonlinear effect of anomalously deep penetration of an external radio-frequency electric field into a plasma is described. A self-consistent kinetic treatment reveals a transition region between the sheath and the plasma. Because of the electron velocity modulation in the sheath, bunches in the energetic electron density are formed in the transition region adjusted to the sheath. The width of the region is of order V(subscript T)/omega, where V(subscript T) is the electron thermal velocity, and w is frequency of the electric field. The presence of the electric field in the transition region results in a cooling of the energetic electrons and an additional heating of the cold electrons in comparison with the case when the transition region is neglected

  15. Anomalous Capacitive Sheath with Deep Radio Frequency Electric Field Penetration

    Energy Technology Data Exchange (ETDEWEB)

    Igor D. Kaganovich

    2002-01-18

    A novel nonlinear effect of anomalously deep penetration of an external radio-frequency electric field into a plasma is described. A self-consistent kinetic treatment reveals a transition region between the sheath and the plasma. Because of the electron velocity modulation in the sheath, bunches in the energetic electron density are formed in the transition region adjusted to the sheath. The width of the region is of order V(subscript T)/omega, where V(subscript T) is the electron thermal velocity, and w is frequency of the electric field. The presence of the electric field in the transition region results in a cooling of the energetic electrons and an additional heating of the cold electrons in comparison with the case when the transition region is neglected.

  16. Electrically Conductive Anodized Aluminum Surfaces

    Science.gov (United States)

    Nguyen, Trung Hung

    2006-01-01

    Anodized aluminum components can be treated to make them sufficiently electrically conductive to suppress discharges of static electricity. The treatment was conceived as a means of preventing static electric discharges on exterior satin-anodized aluminum (SAA) surfaces of spacecraft without adversely affecting the thermal-control/optical properties of the SAA and without need to apply electrically conductive paints, which eventually peel off in the harsh environment of outer space. The treatment can also be used to impart electrical conductivity to anodized housings of computers, medical electronic instruments, telephoneexchange equipment, and other terrestrial electronic equipment vulnerable to electrostatic discharge. The electrical resistivity of a typical anodized aluminum surface layer lies between 10(exp 11) and 10(exp 13) Omega-cm. To suppress electrostatic discharge, it is necessary to reduce the electrical resistivity significantly - preferably to surface becomes covered and the pores in the surface filled with a transparent, electrically conductive metal oxide nanocomposite. Filling the pores with the nanocomposite reduces the transverse electrical resistivity and, in the original intended outer-space application, the exterior covering portion of the nanocomposite would afford the requisite electrical contact with the outer-space plasma. The electrical resistivity of the nanocomposite can be tailored to a value between 10(exp 7) and 10(exp 12) Omega-cm. Unlike electrically conductive paint, the nanocomposite becomes an integral part of the anodized aluminum substrate, without need for adhesive bonding material and without risk of subsequent peeling. The electrodeposition process is compatible with commercial anodizing production lines. At present, the electronics industry uses expensive, exotic, electrostaticdischarge- suppressing finishes: examples include silver impregnated anodized, black electroless nickel, black chrome, and black copper. In

  17. Dengue Fever with rectus sheath hematoma: a case report.

    Science.gov (United States)

    Sharma, Anurag; Bhatia, Sonia; Singh, Rajendra Pratap; Malik, Gaurav

    2014-04-01

    Dengue fever, also known as breakbone fever, is an infectious tropical disease caused by the Dengue virus. It is associated with a number of complications, which are well documented. However, Dengue fever associated with rectus sheath hematoma (RSH) is a very rare complication. Only one case report has been published prior supporting the association of Dengue fever with RSH. We report a case of Dengue fever who presented with RSH and was successfully treated conservatively. RSH is also an uncommon cause of acute abdominal pain. It is accumulation of blood in the sheath of the rectus abdominis, secondary to rupture of an epigastric vessel or muscle tear.

  18. Photovoltaic building sheathing element with anti-slide features

    Science.gov (United States)

    Keenihan, James R.; Langmaid, Joseph A.; Lopez, Leonardo C.

    2015-09-08

    The present invention is premised` upon an assembly that includes at least a photovoltaic building sheathing element capable of being affixed on a building structure, the photovoltaic building sheathing element. The element including a photovoltaic cell assembly, a body portion attached to one or more portions of the photovoltaic cell assembly; and at feast a first and a second connector assembly capable of directly or indirectly electrically connecting the photovoltaic cell assembly to one or more adjoining devices; wherein the body portion includes one or more geometric features adapted to engage a vertically adjoining device before installation.

  19. Fabrication and use of zircaloy/tantalum-sheathed cladding thermocouples and molybdenum/rhenium-sheathed fuel centerline thermocouples

    International Nuclear Information System (INIS)

    Wilkins, S.C.; Sepold, L.K.

    1985-01-01

    The thermocouples described in this report are zircaloy/tantalum-sheathed and molybdenum/rhenium alloy-sheathed instruments intended for fuel rod cladding and fuel centerline temperature measurements, respectively. Both types incorporate beryllium oxide insulation and tungsten/rhenium alloy thermoelements. These thermocouples, operated at temperatures of 2000 0 C and above, were developed for use in the internationally sponsored Severe Fuel Damage test series in the Power Burst Facility. The fabrication steps for both thermocouple types are described in detail. A laser-welding attachment technique for the cladding-type thermocouple is presented, and experience with alternate materials for cladding and fuel therocouples is discussed

  20. Enhancing Micro-Cathode Arc Thruster (muCAT) Plasma Generation to Analyze Magnetic Field Angle Effects on Sheath Formation in Hall Thrusters

    Science.gov (United States)

    Lukas, Joseph Nicholas

    Using a Delta IV or Atlas V launch vehicle to send a payload into Low Earth Orbit can cost between 13,000 and 14,000 per kilogram. With payloads that utilize a propulsion system, maximizing the efficiency of that propulsion system would not only be financially beneficial, but could also increase the range of possible missions and allow for a longer mission lifetime. This dissertation looks into efficiency increases in the Micro-Cathode Arc Thruster (muCAT) and Hall Thruster. The muCAT is an electric propulsion device that ablates solid cathode material, through an electrical arc discharge, to create plasma and ultimately produce thrust. About 90% of the arc discharge current is conducted by electrons, which go toward heating the anode and contribute very little to thrust, with only the remaining 10% going toward thrust in the form of ion current. I will discuss the results of an experiment in which electron heating on a low melting point anode was shown to increase ion current, which theoretically should increase thrust levels at low frequencies. Another feature of the muCAT is the use of an external magnetic solenoid which increases thrust, ion current, and causes uniform cathode erosion. An experiment has shown that efficiency can also be increased by removing the external magnetic field power supply and, instead, utilizing the residual arc current to power the magnetic solenoid. A Hall Thruster is a type of electric propulsion device that accelerates ions across an electric potential between an anode and magnetically trapped electrons. The limiting factor in Hall Thruster operation is the lifetime of the wall material. During operation, a positively charged layer forms over the surface of the walls, known as a plasma sheath, which contributes to wall erosion. Therefore, by reducing or eliminating the sheath layer, Hall Thruster operational lifetime can increase. Computational modeling has shown that large magnetic field angles and large perpendicular electric

  1. Anodic oxide films on tungsten

    International Nuclear Information System (INIS)

    Di Paola, A.; Di Quarto, F.; Sunseri, C.

    1980-01-01

    Scanning electron microscopy was used to investigate the morphology of anodic oxide films on tungsten, obtained in various conditions of anodization. Studies were made of the growth of porous films, whose thickness increases with time and depends upon the current density. Temperature and electrolyte composition influence the film morphology. Gravimetric measurements of film dissolution at 70 0 C show that after a transient time, the rate of metal dissolution and that of film formation coincide. The porous films thicken because tungsten dissolves as WO 2 2+ and precipitates as WO 3 .H 2 O. (author)

  2. sheath characteristics in multi-component plasma with negative ions

    Indian Academy of Sciences (India)

    Abstract. Properties of steady state ion sheath formed in front of a negatively biased metal plate under the influence of negative ions have been investigated in collisionless argon/SF6 plasma. This experiment is carried out at a fixed discharge voltage and fixed filament heating power. In this experiment, the decrement in ...

  3. Synovial sarcoma mimicking benign peripheral nerve sheath tumor

    Energy Technology Data Exchange (ETDEWEB)

    Larque, Ana B.; Nielsen, G.P.; Chebib, Ivan [Massachusetts General Hospital and Harvard Medical School, Department of Pathology, Boston, MA (United States); Bredella, Miriam A. [Massachusetts General Hospital and Harvard Medical School, Department of Radiology, Boston, MA (United States)

    2017-11-15

    To assess the radiographic and clinicopathologic features of synovial sarcoma of the nerve that were clinically or radiologically interpreted as benign peripheral nerve sheath tumor. Five patients with synovial sarcoma arising from the peripheral nerve and interpreted clinically and radiologically as peripheral nerve sheath tumors were identified. Clinicopathologic and imaging features were evaluated. There were three females and two males, ranging in age from 28 to 50 (mean 35.8) years. Most patients (4/5) complained of a mass, discomfort or pain. MR images demonstrated a heterogeneous, enhancing, soft tissue mass contiguous with the neurovascular bundle. On histologic examination, most tumors were monophasic synovial sarcoma (4/5). At the time of surgery, all tumors were noted to arise along or within a peripheral nerve. All patients were alive with no evidence of disease with median follow-up of 44 (range 32-237) months. For comparison, approximately 775 benign peripheral nerve sheath tumors of the extremities were identified during the same time period. Primary synovial sarcoma of the nerve can mimic peripheral nerve sheath tumors clinically and on imaging and should be included in the differential diagnosis for tumors arising from peripheral nerves. (orig.)

  4. Sheath and plasma parameters in a magnetized plasma system

    Indian Academy of Sciences (India)

    In this con- trast, Behnel [4] considered a magnetic field (B) which is parallel to the wall, provides the ion-charge exchange collision with the mean free path λ ^p , where pะ is the ion-gyro radius. According to this model, there is no ion motion parallel to the magnetic field lines and no extra plasma pre-sheath was considered.

  5. The Bohm criterion for a dusty plasma sheath

    Indian Academy of Sciences (India)

    undergo temperature fluctuations due to collision, the mean square fluctuation in their temperature is much less than the equilibrium temperature. The problem of sheath dynamics with the plasma–wall interactions is of great importance in a number of areas, viz., plasma ion implantation, high-density com- puter chip ...

  6. Malignant Peripheral Nerve Sheath Tumor: MRI and CT Findings

    Directory of Open Access Journals (Sweden)

    K. O. Kragha

    2015-01-01

    important in its diagnosis. A rare case of MPNST that produced urinary retention and bowel incontinence is presented that may aid clinicians in the diagnosis of this rare clinical entity. Motor weakness, central enhancement, and immunohistochemistry may assist in the diagnosis of MPNST and differentiation between benign peripheral nerve sheath tumor (BPNST and MPNST.

  7. Mineralized fibroma of the tendon sheath presenting as a bursitis

    Energy Technology Data Exchange (ETDEWEB)

    Le Corroller, Thomas; Champsaur, Pierre [Hopital Sainte-Marguerite, Service de Radiologie, Marseille (France); Faculte de Medecine de Marseille, Departement d' Anatomie, Marseille (France); Bouvier-Labit, Corinne [Hopital La Timone, Service d' Anatomopathologie, Marseille (France); Sbihi, Abderrahmane [Clinique Juge, Service de Chirurgie orthopedique, Marseille (France)

    2008-12-15

    We report on the clinical, imaging - including ultrasound, computed tomography, and magnetic resonance imaging - and histological features of a fibroma of the tendon sheath with mineralized chondroid and osseous metaplasia, presenting as a semimembranosus bursitis. The anatomical characteristics of the semimembranosus bursa are demonstrated by dissection in a cadaveric specimen and correlated with the imaging findings in our patient. (orig.)

  8. Mineralized fibroma of the tendon sheath presenting as a bursitis

    International Nuclear Information System (INIS)

    Le Corroller, Thomas; Champsaur, Pierre; Bouvier-Labit, Corinne; Sbihi, Abderrahmane

    2008-01-01

    We report on the clinical, imaging - including ultrasound, computed tomography, and magnetic resonance imaging - and histological features of a fibroma of the tendon sheath with mineralized chondroid and osseous metaplasia, presenting as a semimembranosus bursitis. The anatomical characteristics of the semimembranosus bursa are demonstrated by dissection in a cadaveric specimen and correlated with the imaging findings in our patient. (orig.)

  9. The Bohm criterion for a dusty plasma sheath

    Indian Academy of Sciences (India)

    Abstract. The formation of the sheath in a dusty plasma is investigated. The Bohm criterion is derived for two different cases: (a) when electrons are in thermodynamic equilibrium and dust grains provide the immobile, stationary background and (b) when both electrons and ions are in thermodynamic equilibrium and dust ...

  10. Dural Arteriovenous Fistula of the Optic Nerve Sheath

    NARCIS (Netherlands)

    van den Berg, René; Smagge, Lucas E.; Saeed, Peerooz; Majoie, Charles B.

    2009-01-01

    Dural arterial-venous fistulas (dAVf) are acquired vascular lesions that can give a variety of symptoms, depending on anatomical localization and venous drainage pattern. We present a very unusual case of a dAVf localized at the level of the optic nerve sheath including discussion of the vascular

  11. Extraction of antioxidant pigments from dye sorghum leaf sheaths

    NARCIS (Netherlands)

    Kayode, A.P.P.; Bara, C.A.; Dalode-Vieira, G.; Linnemann, A.R.; Nout, M.J.R.

    2012-01-01

    Extraction of antioxidant biocolorant pigments from leaf sheaths of dye sorghum was optimized. Effects of temperature and ethanol concentration of the extraction solvent on the concentrations of the 3-deoxyanthocyanidins, total phenolics and total anthocyanins, and the colour parameters of the

  12. Anodic selective functionalization of cyclic amine derivatives

    OpenAIRE

    Onomura, Osamu

    2012-01-01

    Anodic reactions are desirable methods from the viewpoint of Green Chemistry, since no toxic oxidants are necessary for the oxidation of organic molecules. This review introduces usefulness of anodic oxidation and successive reaction for selective functionalization of cyclic amine derivatives.

  13. Stable sheath formation in expanding magnetic field to divertor plate

    International Nuclear Information System (INIS)

    Tomita, Y.; Takayama, A.; Takamaru, H.; Sato, T.

    2001-01-01

    The stable sheath formation in expanding magnetic field to a divertor plate was studied theoretically by one-dimensional analysis. In fusion devices the magnetic field is expanding in the direction of the plate, i.e. the magnitude of magnetic field is decreasing to the plate. In this configuration ions are accelerated to the plate due to the gradient of the magnetic field strength, so called a mirror force. The bombardment of accelerated ions to the plate may cause several severe problems to fusion plasmas, for example, release of large amount of impurities from the diverter plate. Limited research efforts have been carried out describing magnetic field effects on various potential formation and particle and heat fluxes to the divertor plate. The plasma-wall interaction in an oblique to the plate but uniform magnetic field has been studied by means of 1D-PIC numerical simulation. This analysis shows the formation of a quasi-neutral magnetic pre-sheath preceding the electrostatic Debye sheath, which scales to the ion gyroradius at the sound speed and to the incidence angle of the magnetic field. Sato clarifies this magnetic pre-sheath is attributed to the ion polarisation drift by the two dimensional kinetic analysis. None of effects, however, of non-uniformity of the magnetic field has been taken into account on the stable electrostatic potential and sheath formation. In this paper, we consider a collisionless sheath model between an infinite metal plate and a quasi-neutral plasma in the expanding magnetic field to the plate. One dimensional kinetic analysis leads that a condition for flow velocity of ions at a plasma-sheath boundary is more restricted than that of the uniform magnetic field, which should be larger than the ion sound speed. The difference, however, between both cases is an order of the Debye length to a plasma radius, which is negligible small. The requirement for the ion flow velocity inside the plasma is obtained from the condition of the quasi

  14. File list: ALL.Neu.50.AllAg.Nerve_Sheath_Neoplasms [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Neu.50.AllAg.Nerve_Sheath_Neoplasms mm9 All antigens Neural Nerve Sheath Neopla...sms SRX337965 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/ALL.Neu.50.AllAg.Nerve_Sheath_Neoplasms.bed ...

  15. File list: Pol.Neu.10.AllAg.Nerve_Sheath_Neoplasms [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Neu.10.AllAg.Nerve_Sheath_Neoplasms mm9 RNA polymerase Neural Nerve Sheath Neop...lasms http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Pol.Neu.10.AllAg.Nerve_Sheath_Neoplasms.bed ...

  16. Malignant peripheral nerve sheath tumour of the bladder associated with neurofibromatosis I.

    LENUS (Irish Health Repository)

    O'Brien, Julie

    2008-12-01

    Neurofibromatosis is a hamartomatous disorder of autonomic peripheral nerve sheaths associated with peripheral nerve sheath tumours. Most tumours are neurofibromas; however, the genitourinary system is rarely involved. We present a rare case of a nerve sheath tumour of the bladder in a young patient, which was discovered to be malignant.

  17. 30 CFR 15.32 - Tolerances for weight of explosive, sheath, wrapper, and specific gravity.

    Science.gov (United States)

    2010-07-01

    ..., wrapper, and specific gravity. 15.32 Section 15.32 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... explosive, sheath, wrapper, and specific gravity. (a) The weight of the explosive, the sheath, and the outer.... (c) The specific gravity of the explosive and sheath shall be within ±7.5 percent of that specified...

  18. Community structure of filamentous, sheath-building sulfur bacteria, Thioploca spp, off the coast of Chile

    DEFF Research Database (Denmark)

    Schulz, HN; Jørgensen, BB; Fossing, HA

    1996-01-01

    of Concepcion was investigated,vith respect to biomass, species distribution, and three-dimensional orientation of the sheaths, Thioploca sheaths and filaments were found across the whole shelf area within the oxygen minimum zone, The maximum wet weight of sheaths, 800 g m(-2), was found at a depth of 90 m...

  19. File list: His.Neu.05.AllAg.Nerve_Sheath_Neoplasms [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Neu.05.AllAg.Nerve_Sheath_Neoplasms mm9 Histone Neural Nerve Sheath Neoplasms h...ttp://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Neu.05.AllAg.Nerve_Sheath_Neoplasms.bed ...

  20. File list: Oth.Neu.10.AllAg.Nerve_Sheath_Neoplasms [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Neu.10.AllAg.Nerve_Sheath_Neoplasms mm9 TFs and others Neural Nerve Sheath Neoplasms... SRX337965 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Oth.Neu.10.AllAg.Nerve_Sheath_Neoplasms.bed ...

  1. File list: Oth.Neu.05.AllAg.Nerve_Sheath_Neoplasms [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Neu.05.AllAg.Nerve_Sheath_Neoplasms mm9 TFs and others Neural Nerve Sheath Neoplasms... SRX337965 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Oth.Neu.05.AllAg.Nerve_Sheath_Neoplasms.bed ...

  2. File list: Pol.Neu.05.AllAg.Nerve_Sheath_Neoplasms [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Neu.05.AllAg.Nerve_Sheath_Neoplasms mm9 RNA polymerase Neural Nerve Sheath Neoplasms... http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Pol.Neu.05.AllAg.Nerve_Sheath_Neoplasms.bed ...

  3. File list: Unc.Neu.05.AllAg.Nerve_Sheath_Neoplasms [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Unc.Neu.05.AllAg.Nerve_Sheath_Neoplasms mm9 Unclassified Neural Nerve Sheath Neoplasms... http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Unc.Neu.05.AllAg.Nerve_Sheath_Neoplasms.bed ...

  4. File list: Pol.Neu.20.AllAg.Nerve_Sheath_Neoplasms [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Neu.20.AllAg.Nerve_Sheath_Neoplasms mm9 RNA polymerase Neural Nerve Sheath Neoplasms... http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Pol.Neu.20.AllAg.Nerve_Sheath_Neoplasms.bed ...

  5. File list: Oth.Neu.50.AllAg.Nerve_Sheath_Neoplasms [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Neu.50.AllAg.Nerve_Sheath_Neoplasms mm9 TFs and others Neural Nerve Sheath Neoplasms... SRX337965 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Oth.Neu.50.AllAg.Nerve_Sheath_Neoplasms.bed ...

  6. File list: ALL.Neu.10.AllAg.Nerve_Sheath_Neoplasms [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Neu.10.AllAg.Nerve_Sheath_Neoplasms mm9 All antigens Neural Nerve Sheath Neoplasms... SRX337965 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/ALL.Neu.10.AllAg.Nerve_Sheath_Neoplasms.bed ...

  7. File list: His.Neu.50.AllAg.Nerve_Sheath_Neoplasms [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Neu.50.AllAg.Nerve_Sheath_Neoplasms mm9 Histone Neural Nerve Sheath Neoplasms h...ttp://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Neu.50.AllAg.Nerve_Sheath_Neoplasms.bed ...

  8. File list: DNS.Neu.10.AllAg.Nerve_Sheath_Neoplasms [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available DNS.Neu.10.AllAg.Nerve_Sheath_Neoplasms mm9 DNase-seq Neural Nerve Sheath Neoplasms... http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/DNS.Neu.10.AllAg.Nerve_Sheath_Neoplasms.bed ...

  9. File list: His.Neu.10.AllAg.Nerve_Sheath_Neoplasms [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Neu.10.AllAg.Nerve_Sheath_Neoplasms mm9 Histone Neural Nerve Sheath Neoplasms h...ttp://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Neu.10.AllAg.Nerve_Sheath_Neoplasms.bed ...

  10. File list: DNS.Neu.50.AllAg.Nerve_Sheath_Neoplasms [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  11. File list: Unc.Neu.20.AllAg.Nerve_Sheath_Neoplasms [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  12. File list: DNS.Neu.05.AllAg.Nerve_Sheath_Neoplasms [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available DNS.Neu.05.AllAg.Nerve_Sheath_Neoplasms mm9 DNase-seq Neural Nerve Sheath Neoplasms... http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/DNS.Neu.05.AllAg.Nerve_Sheath_Neoplasms.bed ...

  13. File list: Unc.Neu.50.AllAg.Nerve_Sheath_Neoplasms [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Unc.Neu.50.AllAg.Nerve_Sheath_Neoplasms mm9 Unclassified Neural Nerve Sheath Neoplasms... http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Unc.Neu.50.AllAg.Nerve_Sheath_Neoplasms.bed ...

  14. File list: Unc.Neu.10.AllAg.Nerve_Sheath_Neoplasms [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Unc.Neu.10.AllAg.Nerve_Sheath_Neoplasms mm9 Unclassified Neural Nerve Sheath Neoplasms... http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Unc.Neu.10.AllAg.Nerve_Sheath_Neoplasms.bed ...

  15. File list: ALL.Neu.05.AllAg.Nerve_Sheath_Neoplasms [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Neu.05.AllAg.Nerve_Sheath_Neoplasms mm9 All antigens Neural Nerve Sheath Neoplasms... SRX337965 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/ALL.Neu.05.AllAg.Nerve_Sheath_Neoplasms.bed ...

  16. File list: Oth.Neu.20.AllAg.Nerve_Sheath_Neoplasms [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Neu.20.AllAg.Nerve_Sheath_Neoplasms mm9 TFs and others Neural Nerve Sheath Neoplasms... SRX337965 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Oth.Neu.20.AllAg.Nerve_Sheath_Neoplasms.bed ...

  17. File list: His.Neu.20.AllAg.Nerve_Sheath_Neoplasms [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Neu.20.AllAg.Nerve_Sheath_Neoplasms mm9 Histone Neural Nerve Sheath Neoplasms h...ttp://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Neu.20.AllAg.Nerve_Sheath_Neoplasms.bed ...

  18. File list: Pol.Neu.50.AllAg.Nerve_Sheath_Neoplasms [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Neu.50.AllAg.Nerve_Sheath_Neoplasms mm9 RNA polymerase Neural Nerve Sheath Neoplasms... http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Pol.Neu.50.AllAg.Nerve_Sheath_Neoplasms.bed ...

  19. File list: DNS.Neu.20.AllAg.Nerve_Sheath_Neoplasms [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  20. File list: ALL.Neu.20.AllAg.Nerve_Sheath_Neoplasms [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Neu.20.AllAg.Nerve_Sheath_Neoplasms mm9 All antigens Neural Nerve Sheath Neoplasms... SRX337965 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/ALL.Neu.20.AllAg.Nerve_Sheath_Neoplasms.bed ...

  1. High voltage switch triggered by a laser-photocathode subsystem

    Science.gov (United States)

    Chen, Ping; Lundquist, Martin L.; Yu, David U. L.

    2013-01-08

    A spark gap switch for controlling the output of a high voltage pulse from a high voltage source, for example, a capacitor bank or a pulse forming network, to an external load such as a high gradient electron gun, laser, pulsed power accelerator or wide band radar. The combination of a UV laser and a high vacuum quartz cell, in which a photocathode and an anode are installed, is utilized as triggering devices to switch the spark gap from a non-conducting state to a conducting state with low delay and low jitter.

  2. Ellipsometry of anodic film growth

    Energy Technology Data Exchange (ETDEWEB)

    Smith, C.G.

    1978-08-01

    An automated computer interpretation of ellisometer measurements of anodic film growth was developed. Continuous mass and charge balances were used to utilize more fully the time dependence of the ellipsometer data and the current and potential measurements. A multiple-film model was used to characterize the growth of films which proceeds via a dissolution--precipitation mechanism; the model also applies to film growth by adsorption and nucleation mechanisms. The characteristic parameters for film growth describe homogeneous and heterogeneous crystallization rates, film porosities and degree of hydration, and the supersaturation of ionic species in the electrolyte. Additional descriptions which may be chosen are patchwise film formation, nonstoichiometry of the anodic film, and statistical variations in the size and orientation of secondary crystals. Theories were developed to describe the optical effects of these processes. An automatic, self-compensating ellipsometer was used to study the growth in alkaline solution of anodic films on silver, cadmium, and zinc. Mass-transport conditions included stagnant electrolyte and forced convection in a flow channel. Multiple films were needed to characterize the optical properties of these films. Anodic films grew from an electrolyte supersatuated in the solution-phase dissolution product. The degree of supersaturation depended on transport conditions and had a major effect on the structure of the film. Anodic reaction rates were limited by the transport of charge carriers through a primary surface layer. The primary layers on silver, zinc, and cadmium all appeared to be nonstoichiometric, containing excess metal. Diffusion coefficients, transference numbers, and the free energy of adsorption of zinc oxide were derived from ellipsometer measurements. 97 figures, 13 tables, 198 references.

  3. Controller Architectures for Switching

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Poulsen, Niels Kjølstad

    2009-01-01

    This paper investigate different controller architectures in connection with controller switching. The controller switching is derived by using the Youla-Jabr-Bongiorno-Kucera (YJBK) parameterization. A number of different architectures for the implementation of the YJBK parameterization...... are described and applied in connection with controller switching. An architecture that does not include inversion of the coprime factors is introduced. This architecture will make controller switching particular simple....

  4. Electric fields in the sheath formed in a 300 mm, dual frequency capacitive argon discharge

    International Nuclear Information System (INIS)

    Barnat, E V; Miller, P A; Hebner, G A; Paterson, A M; Panagopoulos, T; Hammond, E; Holland, J

    2007-01-01

    The spatial structure and temporal evolution of the electric fields in a sheath formed in a dual frequency, 300 mm capacitive argon discharge are measured as functions of relative mixing between a low frequency current and a high frequency current. It is found that the overall structure of the sheath (potential across the sheath and the thickness of the sheath) are dominated by the lower frequency component while (smaller) oscillations in these quantities are dictated by the higher frequency component. Comparisons of the measured spatial and temporal profiles are made for Lieberman's and Robiche et al sheath model and with a particle in a cell calculation

  5. Fabrication of advanced design (grooved) cermet anodes

    Energy Technology Data Exchange (ETDEWEB)

    Windisch, C.F. Jr. [Pacific Northwest Lab., Richland, WA (United States); Huettig, F.R. [Ceramic Magnetics, Inc., Fairfield, NJ (United States)

    1993-05-01

    Attempts were made to fabricate full-size anodes with advanced, or grooved, design using isostatic pressing, slip casting injection molding. Of the three approaches, isostatic pressing produced an anode with dimensions nearest to the target specifications, without serious macroscopic flaws. This approach is considered the most promising for making advanced anodes for aluminum smelting. However, significant work still remains to optimize the physical properties and microstructure of the anode, both of which were significantly different from that of previous anodes. Injection molding and slip casting yielded anode materials with serious deficiencies, including cracks and holes. Injection molding gave cermet material with the best intrinsic microstructure, i.e., the microstructure of the material between macroscopic flaws was very similar to that of anodes previously made at PNL. Reason for the similarity may have to do with amount of residual binder in the material prior to sintering.

  6. Magnesium sacrificial anode behavior at elevated temperature

    International Nuclear Information System (INIS)

    Othman, Mohsen Othman

    2006-01-01

    Magnesium sacrificial anode coupled to mild steel was tasted in sodium chloride and tap water environments at elevated temperatures. The anode failed to protect the mild steel specimens in tap water environment at all temperatures specified. This was partly due to low conductivity of this medium. The temperature factor did not help to activate the anode in this medium. In sodium chloride environment the anode demonstrated good protection for steel cathodes. The weight loss was high for magnesium in sodium chloride environment particularly beyond 60 degree centigrade. In tap water environment the weight loss was negligible for the anode. It also suffered localized shallow pitting corrosion. Magnesium anode cannot be utilized where high temperature is involved particularly in high conductivity mediums. Protection of structures containing high resistivity waters is not feasible using sacrificial anode system. (author)

  7. In vivo engineering of a functional tendon sheath in a hen model.

    Science.gov (United States)

    Xu, Liang; Cao, Dejun; Liu, Wei; Zhou, Guangdong; Zhang, Wen Jie; Cao, Yilin

    2010-05-01

    Repair of injured tendon sheath remains a major challenge and this study explored the possibility of in vivo reconstruction of a tendon sheath with tendon sheath derived cells and polyglycolic acid (PGA) fibers in a Leghorn hen model. Total 55 Leghorn hens with a 1cm tendon sheath defect created in the left middle toe of each animal were randomly assigned into: (1) experimental group (n=19) that received a cell-PGA construct; (2) scaffold control group (n=18) that received a cell-free PGA scaffold; (3) blank control group (n=18) with the defect untreated. Tendon sheath cells were isolated, in vitro expanded, and seeded onto PGA scaffolds. After in vitro culture for 7 days, the constructs were in vivo implanted to repair the sheath defects. Alcian blue staining confirmed the ability of cultured cells to produce specific matrices containing acidic carboxyl mucopolysaccharide (mainly hyaluronic acid). In addition, the engineered sheath formed a relatively mature structure at 12 weeks post-surgery, which was similar to that of native counterpart, including a smooth inner surface, a well-developed sheath histological structure with a clear space between the tendon and the engineered sheath. More importantly, Work of Flexion assay revealed that the tendons needed less power consumption to glide inside the engineered sheath when compared to the tendons which were surrounded by scar-repaired tissues, indicating that the engineered sheaths had gained the function to a certain extent of preventing tendon adhesion. Taken together, these results suggest that tendon sheaths that are functionally and structurally similar to native sheaths are possible to be engineered in vivo using tendon sheath cells and PGA scaffolds. Copyright 2010 Elsevier Ltd. All rights reserved.

  8. Co-electrospinning fabrication and photocatalytic performance of TiO2/SiO2 core/sheath nanofibers with tunable sheath thickness

    International Nuclear Information System (INIS)

    Cao, Houbao; Du, Pingfan; Song, Lixin; Xiong, Jie; Yang, Junjie; Xing, Tonghai; Liu, Xin; Wu, Rongrong; Wang, Minchao; Shao, Xiaoli

    2013-01-01

    Graphical abstract: - Highlights: • The core–sheath TiO 2 /SiO 2 nanofibers were fabricated by co-electrospinning technique. • The catalytic property of nanofibers with different sheath thickness was studied. • The potential methods of improving catalytic efficiency are suggested. - Abstract: In this paper, core/sheath TiO 2 /SiO 2 nanofibers with tunable sheath thickness were directly fabricated via a facile co-electrospinning technique with subsequent calcination at 500 °C. The morphologies and structures of core/sheath TiO 2 /SiO 2 nanofibers were characterized by TGA, FESEM, TEM, FTIR, XPS and BET. It was found that the 1D core/sheath nanofibers are made up of anatase–rutile TiO 2 core and amorphous SiO 2 sheath. The influences of SiO 2 sheath and its thickness on the photoreactivity were evaluated by observing photo-degradation of methylene blue aqueous solution under the irradiation of UV light. Compared with pure TiO 2 nanofibers, the core/sheath TiO 2 /SiO 2 nanofibers performed a better catalytic performance. That was attributed to not only efficient separation of hole–electron pairs resulting from the formation of heterojunction but also larger surface area and surface silanol group which will be useful to provide higher capacity for oxygen adsorption to generate more hydroxyl radicals. And the optimized core/sheath TiO 2 /SiO 2 nanofibers with a sheath thickness of 37 nm exhibited the best photocatalytic performance

  9. Moisture Durability with Vapor-Permeable Insulating Sheathing

    Energy Technology Data Exchange (ETDEWEB)

    Lepage, R. [Building Science Corporation, Somerville, MA (United States); Lstiburek, J. [Building Science Corporation, Somerville, MA (United States)

    2013-09-01

    Exterior sheathing insulation is an effective strategy in increasing the overall R-value of wall assemblies; other benefits include decreasing the effects of thermal bridging and increasing the moisture durability of the built assembly. Vapor-permeable exterior insulation, such as mineral board or expanded polystyrene foam, are one such product that may be used to achieve these benefits. However,uncertainty exists on the effects of inward driven moisture and the interaction of increased sheathing temperatures on the moisture durability of the edifice. To address these concerns, Building Science Corporation (BSC) conducted a series of hygrothermal models for cities representing a range of different climate zones. This report describes the research project, key research questions, and theprocedures utilized to analyse the problems.

  10. Moisture Durability with Vapor-Permeable Insulating Sheathing

    Energy Technology Data Exchange (ETDEWEB)

    Lepage, R. [Building Science Corporation, Somerville, MA (United States); Lstiburek, J. [Building Science Corporation, Somerville, MA (United States)

    2013-09-01

    Exterior sheathing insulation is an effective strategy in increasing the overall R-value of wall assemblies; other benefits include decreasing the effects of thermal bridging and increasing the moisture durability of the built assembly. Vapor-permeable exterior insulation, such as mineral board or expanded polystyrene foam, are one such product that may be used to achieve these benefits. However, uncertainty exists on the effects of inward driven moisture and the interaction of increased sheathing temperatures on the moisture durability of the edifice. To address these concerns, Building Science Corporation (BSC) conducted a series of hygrothermal models for cities representing a range of different climate zones. This report describes the research project, key research questions, and the procedures utilized to analyse the problems.

  11. Out-of-pile fatigue tests on Zircaloy CANDU sheaths

    International Nuclear Information System (INIS)

    Roth, Maria; Ciocanescu, Marin; Gheorghiu, Constantin; Pitigoi, Vasile; Ducu, Catalin; Malinovschi, Viorel

    2005-01-01

    The paper outlines the achievements in the nuclear research field of cooperation on Nuclear Fuel performed as part of the collaboration under the Memorandum of Understanding, settled between Atomic Energy of Canada Limited (AECL) and Institute for Nuclear Research (ICN), The sheath behavior was simulated using out-of-pile fatigue tests, in conditions identical with those met during the operation in power cycling of CANDU reactor, except for irradiation. A special test rig, designed and carried-out at ICN ensured the experimental requirements according to the Canadian testing procedure. The description of the experimental setup and monitoring of testing parameters were also done. The fatigue life time, expressed as number of cycles to rupture (N), was measured as a function of the total strain amplitude (e) induced in the Zircaloy-4 sheath samples. Strain-Life time fatigue dependence (e-N) under low cycle fatigue conditions was also verified using the Coffin-Manson correlation. (authors)

  12. Stable sheath formation in expanding magnetic field to divertor plate

    International Nuclear Information System (INIS)

    Tomita, Y.; Takayama, A.; Takamaru, H.; Sato, T.

    2002-01-01

    The stable sheath formation and the effects of charge exchange collisions of ions with cold neutrals for the stable presheath formation in an expanding magnetic field towards a divertor plate is studied by a one-dimensional analysis. The requirement for flow velocity of ions at a plasma-sheath boundary is more restricted than that of the uniform magnetic field, which should be greater than the ion sound speed. The difference, however, between both cases is an order of the Debye length to plasma radius, which is negligibly small. The requirement for ion flow velocity inside a quasi-neutral plasma is investigated by taking into account the effects of the charge exchange collisions. Without neutrals in the quasi-neutral plasma, the ion flow velocity at an injection point should be much greater than the ion sound speed. The unisotropic velocity distribution of injected ions with coupling the expanding magnetic field and the charge exchange collisions might mitigate this requirement. (orig.)

  13. Zircaloy-sheathed element rods fitted with thermo-couples

    International Nuclear Information System (INIS)

    Bernardy de Sigoyer, B.; Jacques, F.; Thome, P.

    1963-01-01

    In order to carry out thermal conductivity measurements on UO 2 in conditions similar to those under which fuel rods are used, it was necessary to measure the temperature at the interior of a fuel element sheathed in zircaloy. The temperatures are taken with Thermocoax type thermocouples, that is to say fitted with a very thin sheath of stainless steel or Inconel. It is known also that fusion welding of zircaloy onto stainless steel is impossible and that high temperature welded joints are very difficult because of their aggressiveness. The technique used consists in brazing the thermocouples to relatively large stainless steel parts and then joining these plugs by electron bombardment welding to diffused stainless steel-zircaloy couplings. The properties of these diffused couplings and of the brazed joints were studied; the various stages in the fabrication of the containers are also described. (authors) [fr

  14. Photovoltaic sheathing element with one or more tabs

    Energy Technology Data Exchange (ETDEWEB)

    Keenihan, James R; Langmaid, Joseph A; Lopez, Leonardo C.

    2017-02-07

    The present invention is premised upon an assembly that includes at least a photovoltaic sheathing element capable of being affixed on a building structure. The shingle including at least a photovoltaic cell assembly, a body portion attached to one or more portions of the photovoltaic cell assembly. Wherein the body portion includes one or more top peripheral tabs each capable of fitting under one or more vertically adjoining devices.

  15. Cell Based Meniscal Repair Using an Aligned Bioactive Nanofibrous Sheath

    Science.gov (United States)

    2017-07-01

    supplement with each medium change. This has tremendous potential for targeted therapy of focal meniscal lesions . Building on these in vitro results, we...of biomaterials capable of promoting endogenous MSC recruitment to the meniscal lesion . Additionally, the GelMA hydrogel itself possesses good...AWARD NUMBER: W81XWH-15-1-0104 TITLE: Cell-Based Meniscal Repair Using an Aligned Bioactive Nanofibrous Sheath PRINCIPAL INVESTIGATOR

  16. A rare case of bilateral optic nerve sheath meningioma

    OpenAIRE

    Misra, Somen; Misra, Neeta; Gogri, Pratik; Mehta, Rajen

    2014-01-01

    A 60-year-old female presented with gradual, painless, progressive diminution of vision, and progressive proptosis of left eye since 7 years. Ophthalmological examination revealed mild proptosis and total optic atrophy in the left eye. Magnetic resonance imaging (MRI) and computed tomography (CT) brain with orbit showed bilateral optic nerve sheath meningioma (ONSM) involving the intracranial, intracanalicular, intraorbital part of the optic nerve extending up to optic chiasma and left cavern...

  17. A rare case of bilateral optic nerve sheath meningioma

    Science.gov (United States)

    Misra, Somen; Misra, Neeta; Gogri, Pratik; Mehta, Rajen

    2014-01-01

    A 60-year-old female presented with gradual, painless, progressive diminution of vision, and progressive proptosis of left eye since 7 years. Ophthalmological examination revealed mild proptosis and total optic atrophy in the left eye. Magnetic resonance imaging (MRI) and computed tomography (CT) brain with orbit showed bilateral optic nerve sheath meningioma (ONSM) involving the intracranial, intracanalicular, intraorbital part of the optic nerve extending up to optic chiasma and left cavernous sinus. PMID:25005205

  18. A rare case of bilateral optic nerve sheath meningioma

    Directory of Open Access Journals (Sweden)

    Somen Misra

    2014-01-01

    Full Text Available A 60-year-old female presented with gradual, painless, progressive diminution of vision, and progressive proptosis of left eye since 7 years. Ophthalmological examination revealed mild proptosis and total optic atrophy in the left eye. Magnetic resonance imaging (MRI and computed tomography (CT brain with orbit showed bilateral optic nerve sheath meningioma (ONSM involving the intracranial, intracanalicular, intraorbital part of the optic nerve extending up to optic chiasma and left cavernous sinus.

  19. Studies of RF sheaths and diagnostics on IShTAR

    Energy Technology Data Exchange (ETDEWEB)

    Crombé, K., E-mail: Kristel.Crombe@UGent.be [Department of Applied Physics, Ghent University, Ghent (Belgium); LPP-ERM/KMS, Royal Military Academy, Brussels (Belgium); Devaux, S.; Faudot, E.; Heuraux, S.; Moritz, J. [YIJL, UMR7198 CNRS-Université de Lorraine, Nancy (France); D’Inca, R.; Faugel, H.; Fünfgelder, H.; Jacquot, J.; Ochoukov, R. [Max-Planck-Institut für Plasmaphysik, Garching (Germany); Louche, F.; Tripsky, M.; Van Eester, D.; Wauters, T. [LPP-ERM/KMS, Royal Military Academy, Brussels (Belgium); Noterdaeme, J.-M. [Department of Applied Physics, Ghent University, Ghent (Belgium); Max-Planck-Institut für Plasmaphysik, Garching (Germany)

    2015-12-10

    IShTAR (Ion cyclotron Sheath Test ARrangement) is a linear magnetised plasma test facility for RF sheaths studies at the Max-Planck-Institut für Plasmaphysik in Garching. In contrast to a tokamak, a test stand provides more liberty to impose the parameters and gives better access for the instrumentation and antennas. The project will support the development of diagnostic methods for characterising RF sheaths and validate and improve theoretical predictions. The cylindrical vacuum vessel has a diameter of 1 m and is 1.1 m long. The plasma is created by an external cylindrical plasma source equipped with a helical antenna that has been designed to excite the m=1 helicon mode. In inductive mode, plasma densities and electron temperatures have been characterised with a planar Langmuir probe as a function of gas pressure and input RF power. A 2D array of RF compensated Langmuir probes and a spectrometer are planned. A single strap RF antenna has been designed; the plasma-facing surface is aligned to the cylindrical plasma to ease the modelling. The probes will allow direct measurements of plasma density profiles in front of the RF antenna, and thus a detailed study of the density modifications induced by RF sheaths, which influences the coupling. The RF antenna frequency has been chosen to study different plasma wave interactions: the accessible plasma density range includes an evanescent and propagative behaviour of slow or fast waves, and allows the study of the effect of the lower hybrid resonance layer.

  20. Contribution to the physical study of sheath failure detections

    International Nuclear Information System (INIS)

    Mangin, Jean-Paul

    1968-11-01

    As the study of an installation aimed at the detection of sheath failure requires the knowledge of a great number of data related to all the fields of nuclear technology (fission mechanisms, sheath failure mechanisms, recoil of fission products, distribution of the heat transfer fluid in the reactor, techniques of measurement of beta and gamma neutrons, nuclear safety, and so on), this report aims at highlighting some specific issues, more particularly those related to sensors based on delayed neutrons. After having recalled the principles of sheath failure detection, the author presents the various aspects of the study of the formation of fission products and of their passage into the heat transfer fluid: detection by using delayed neutrons, detection by electrostatic collection, passage of fuel fission products into the coolant (recoil, corrosion, gaseous diffusion in the fuel), formation of fission products in the fuel (fission product efficiency). He reports the study of the transport of fission products by the coolant from their place of birth to the place of measurement. He presents the system of measurement by detection of delayed neutrons and by electrostatic collection, reports a sensitivity calculation, a background noise assessment, the determination of detection threshold, and the application of sensitivity and detection thresholds calculations [fr

  1. Experimental Manufacture and Performance Evaluation of Linear Switched Reluctance Motor with HTS Excitation Windings

    Science.gov (United States)

    Hirayama, Tadashi; Oto, Satoshi; Higashijima, Atsushi; Kawabata, Shuma

    This paper presents an experimental manufacture and performance evaluation of prototype linear switched reluctance motor with HTS excitation windings (HTS-LSRM). The Ag-alloy sheathed Bi-2223 tapes are used for HTS coils. We first present a structure of the prototype HTS-LSRM. Next, current-carrying properties of the HTS coils are measured. Furthermore, current and voltage waveforms are measured and we evaluation a control performance of the current and voltage.

  2. Reactions on carbon anodes in aluminium electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Eidet, Trygve

    1997-12-31

    The consumption of carbon anodes and energy in aluminium electrolysis is higher than what is required theoretically. This thesis studies the most important of the reactions that consume anode materials. These reactions are the electrochemical anode reaction and the airburn and carboxy reactions. The first part of the thesis deals with the kinetics and mechanism of the electrochemical anode reaction using electrochemical impedance spectroscopy. The second part deals with air and carboxy reactivity of carbon anodes and studies the effects of inorganic impurities on the reactivity of carbon anodes in the aluminium industry. Special attention is given to sulphur since its effect on the carbon gasification is not well understood. Sulphur is always present in anodes, and it is expected that the sulphur content of available anode cokes will increase in the future. It has also been suggested that sulphur poisons catalyzing impurities in the anodes. Other impurities that were investigated are iron, nickel and vanadium, which are common impurities in anodes which have been reported to catalyze carbon gasification. 88 refs., 92 figs., 24 tabs.

  3. Studies on the transmission of sub-THz waves in magnetized inhomogeneous plasma sheath

    Science.gov (United States)

    Yuan, Kai; Shen, Linfang; Yao, Ming; Deng, Xiaohua; Chen, Zhou; Hong, Lujun

    2018-01-01

    There have been many studies on the sub-terahertz (sub-THz) wave transmission in reentry plasma sheaths. However, only some of them have paid attention to the transmission of sub-THz waves in magnetized plasma sheaths. In this paper, the transmission of sub-THz waves in both unmagnetized and magnetized reentry plasma sheaths was investigated. The impacts of temporal evolution of the plasma sheath on the wave transmission were studied. The transmission of "atmospheric window" frequencies in a magnetized plasma sheath was discussed in detail. According to the study, the power transmission rates (Tp) for the left hand circular (LHC) and the right hand circular modes in the magnetized plasma sheath are obviously higher and lower than those in the unmagnetized plasma sheath, respectively. The Tp of LHC mode increases with both wave frequency and external magnetic field strength. Also, the Tp of LHC mode in both magnetized and unmagnetized plasma sheaths varies with time due to the temporal evolution of the plasma sheath. Moreover, the performance of sub-THz waves in magnetized plasma sheath hints at a new approach to the "blackout" problem. The new approach, which is in the capability of modern technology, is to utilize the communication system operating at 140 GHz with an onboard magnet installed near the antenna.

  4. Investigation on properties of ultrafast switching in a bulk gallium arsenide avalanche semiconductor switch

    International Nuclear Information System (INIS)

    Hu, Long; Su, Jiancang; Ding, Zhenjie; Hao, Qingsong; Yuan, Xuelin

    2014-01-01

    Properties of ultrafast switching in a bulk gallium arsenide (GaAs) avalanche semiconductor switch based on semi-insulating wafer, triggered by an optical pulse, were analyzed using physics-based numerical simulations. It has been demonstrated that when a voltage with amplitude of 5.2 kV is applied, after an exciting optical pulse with energy of 1 μJ arrival, the structure with thickness of 650 μm reaches a high conductivity state within 110 ps. Carriers are created due to photons absorption, and electrons and holes drift to anode and cathode terminals, respectively. Static ionizing domains appear both at anode and cathode terminals, and create impact-generated carriers which contribute to the formation of electron-hole plasma along entire channel. When the electric field in plasma region increases above the critical value (∼4 kV/cm) at which the electrons drift velocity peaks, a domain comes into being. An increase in carrier concentration due to avalanche multiplication in the domains reduces the domain width and results in the formation of an additional domain as soon as the field outside the domains increases above ∼4 kV/cm. The formation and evolution of multiple powerfully avalanching domains observed in the simulations are the physical reasons of ultrafast switching. The switch exhibits delayed breakdown with the characteristics affected by biased electric field, current density, and optical pulse energy. The dependence of threshold energy of the exciting optical pulse on the biased electric field is discussed

  5. Saturated Switching Systems

    CERN Document Server

    Benzaouia, Abdellah

    2012-01-01

    Saturated Switching Systems treats the problem of actuator saturation, inherent in all dynamical systems by using two approaches: positive invariance in which the controller is designed to work within a region of non-saturating linear behaviour; and saturation technique which allows saturation but guarantees asymptotic stability. The results obtained are extended from the linear systems in which they were first developed to switching systems with uncertainties, 2D switching systems, switching systems with Markovian jumping and switching systems of the Takagi-Sugeno type. The text represents a thoroughly referenced distillation of results obtained in this field during the last decade. The selected tool for analysis and design of stabilizing controllers is based on multiple Lyapunov functions and linear matrix inequalities. All the results are illustrated with numerical examples and figures many of them being modelled using MATLAB®. Saturated Switching Systems will be of interest to academic researchers in con...

  6. Effective switching frequency multiplier inverter

    Science.gov (United States)

    Su, Gui-Jia; Peng, Fang Z.

    2007-08-07

    A switching frequency multiplier inverter for low inductance machines that uses parallel connection of switches and each switch is independently controlled according to a pulse width modulation scheme. The effective switching frequency is multiplied by the number of switches connected in parallel while each individual switch operates within its limit of switching frequency. This technique can also be used for other power converters such as DC/DC, AC/DC converters.

  7. FreeSWITCH Cookbook

    CERN Document Server

    Minessale, Anthony

    2012-01-01

    This is a problem-solution approach to take your FreeSWITCH skills to the next level, where everything is explained in a practical way. If you are a system administrator, hobbyist, or someone who uses FreeSWITCH on a regular basis, this book is for you. Whether you are a FreeSWITCH expert or just getting started, this book will take your skills to the next level.

  8. Comparison of Ion Beam opening switch and plasma opening switch performance

    International Nuclear Information System (INIS)

    Greenly, J.R.; Rondeau, G.D.; Sheldon, H.T.; Dreike, P.L.

    1986-01-01

    The Ion Beam opening switch (IBOS) experiment has shown that an intense charge-neutralized ion beam can carry current across a vacuum magnetically-insulated transmission line and then transfer that current to a downstream load quickly. In the IBOS experiment, a 10 cm wide parallel plate transmission line was fed up to 100 kA peak current by a 4Ω, 100 ns pulser. An ion beam of up to 100 A/cm/sup 2/, 100-300 keV protons or carbon was injected through the anode of the line in a 10 cm x 10 cm region. The line terminated in either a 15 nH short circuit or an electron diode with variable gap. The ion beam switch was able to carry up to 70 kA of line current before load current began to flow. This model is also quantitatively consistent with the observation that switch conduction current is not linear with either injected ion beam current or switch area

  9. The in-process control of PVC sheath of a double core cable

    Science.gov (United States)

    Galeeva, N. S.; Redko, V. V.; Redko, L. A.

    2018-01-01

    In this work the possibility of the sheath hermiticity testing by measuring of the cable capacity per unit length variation during spark testing is considered. The research object is 2×0.75 HO3VVH2-F cable. According to the physical modelling it is proved that such defect of sheath as pinhole through the whole thickness of sheath can be registered for the test length 10 cm with test voltage frequencies 1kHz and 10kHz.

  10. Design of Cold-Formed Steel Screw Connections with Gypsum Sheathing at Ambient and Elevated Temperatures

    Directory of Open Access Journals (Sweden)

    Wei Chen

    2016-09-01

    Full Text Available Load-bearing cold-formed steel (CFS walls sheathed with double layers of gypsum plasterboard on both sides have demonstrated good fire resistance and attracted increasing interest for use in mid-rise CFS structures. As the main connection method, screw connections between CFS and gypsum sheathing play an important role in both the structural design and fire resistance of this wall system. However, studies on the mechanical behavior of screw connections with double-layer gypsum sheathing are still limited. In this study, 200 monotonic tests of screw connections with single- or double-layer gypsum sheathing at both ambient and elevated temperatures were conducted. The failure of screw connections with double-layer gypsum sheathing in shear was different from that of single-layer gypsum sheathing connections at ambient temperature, and it could be described as the breaking of the loaded sheathing edge combined with significant screw tilting and the loaded sheathing edge flexing fracture. However, the screw tilting and flexing fracture of the loaded sheathing edge gradually disappear at elevated temperatures. In addition, the influence of the loaded edge distance, double-layer sheathing and elevated temperatures is discussed in detail with clear conclusions. A unified design formula for the shear strength of screw connections with gypsum sheathing is proposed for ambient and elevated temperatures with adequate accuracy. A simplified load–displacement model with the post-peak branch is developed to evaluate the load–displacement response of screw connections with gypsum sheathing at ambient and elevated temperatures.

  11. Estimation of current sheath curvature in plasma focus device using magnetic probes

    International Nuclear Information System (INIS)

    Li, Cai; Yujuan, Shi; Patran, A.; Rawat, R.S.

    2002-01-01

    The dynamics of current sheath, in terms of its speed and sheath curvature, in dense plasma focus device was investigated in its axial acceleration phase using multiple magnetic probes. The investigation was performed for different filling gas pressures of neon. The relative X-ray yields were estimated using a diode X-ray spectrometer. A possible correlation between the current sheath curvature and the X-ray emission was explored. The investigation demonstrates the effective use of relatively simple diagnostics tool, the magnetic probes, in the estimation of current sheath axial speeds and curvatures. (authors)

  12. Usefulness of a guiding sheath for fluoroscopic stent placement in patients with malignant gastroduodenal obstruction.

    Science.gov (United States)

    Park, Jung-Hoon; Song, Ho-Young; Kim, Myoung Sun; Chung, Rosa; Kim, Jin Hyoung; Na, Han Kyu; Nam, Deok Ho

    2013-04-01

    Self-expandable metallic stent placement is widely used to manage malignant gastroduodenal obstructions. However, there are difficulties in negotiating a guidewire (GW) and a stent delivery system (SDS). To investigate feasibility, usefulness, and safety of a guiding sheath for fluoroscopic stent placement in patients with malignant gastroduodenal obstructions. In July 2001 to August 2011, 726 patients with malignant gastroduodenal obstructions underwent stent placement. Guiding sheath was used in patients in whom a GW could not be passed through the obstruction and a SDS failed to reach the obstruction. Sheath usefulness was evaluated based on the ability of the sheath to successfully assist. The technical success rate and the most frequent reasons for the use of a sheath were evaluated. The guiding sheath was needed in 148 of 726 patients (20%). The overall technical success rate was 98% with the guiding sheath. In two of 148 patients, stent placement failed because, the GW could not be passed through the obstruction, in the other, the SDS could not be passed. A minority of patients reported mild discomfort. Patients with pancreatic cancer and duodenal obstruction were significantly more likely to require the use of guiding sheaths (P = 0.002, P guiding sheath for fluoroscopic stent placement appears to be feasible, useful and safe in patients with malignant gastroduodenal obstructions.

  13. Lunar electric fields, surface potential and associated plasma sheaths

    Science.gov (United States)

    Freeman, J. W.; Ibrahim, M.

    1975-01-01

    A review is given of studies of the electric-field environment of the moon. Surface electric potentials are reported for the dayside and terminator regions, electron and ion densities in the plasma sheath adjacent to each surface-potential regime are evaluated, and the corresponding Debye lengths are estimated. The electric fields, which are approximated by the surface potential over the Debye length, are shown to be at least three orders of magnitude higher than the pervasive solar-wind electric field and to be confined to within a few tens of meters of the lunar surface.

  14. Malignant Peripheral Nerve Sheath Tumor - A Case Report

    Directory of Open Access Journals (Sweden)

    Anju N Duttargi

    2007-01-01

    Full Text Available Malignant Peripheral Nerve Sheath Tumor [MPNST] is an extremely rare tumor affecting the oral cavity. It refers to sarcomas that arise from nerve or display features of neural differentiation. Here we present a case of 30-year old male patient with MPNST of right side of the mandible. There was a family history of neurotibromatosis in this case. Histologically, pleomorphic spindle cells with wavy nuclei, light stained cytoplasm, and mitotic activity were observed. The clinical presentation, radiological findings, and light microscopic findings are described in detail. The criteria for diagnosing these tumors and recent advances for diagnosis have also been highlighted.

  15. Miscellaneous conditions of tendons, tendon sheaths, and ligaments.

    Science.gov (United States)

    Dyson, S J; Dik, K J

    1995-08-01

    The use of diagnostic ultrasonography has greatly enhances our ability to diagnose injuries of tendons and tendon sheaths that were previously either unrecognized or poorly understood. For may of these injuries, there is currently only a small amount of follow-up data. This article considers injuries of the deep digital flexor tendon and its accessory ligament, the carpal tunnel syndrome soft tissue swellings on the dorsal aspect of the carpus, intertubercular (bicipital) bursitis and bicipital tendinitis, injuries of the gastrocnemius tendon, common calcaneal tendinitis, rupture of peroneus (fibularis tertius) and ligaments injuries of the back.

  16. Process and electrolyte for applying barrier layer anodic coatings

    International Nuclear Information System (INIS)

    Dosch, R.G.; Prevender, T.S.

    1975-01-01

    Various metals may be anodized, and preferably barrier anodized, by anodizing the metal in an electrolyte comprising quaternary ammonium compound having a complex metal anion in a solvent containing water and a polar, water soluble organic material. (U.S.)

  17. Switched reluctance motor drives

    Indian Academy of Sciences (India)

    Davis RM, Ray WF, Blake RJ 1981 Inverter drive for switched reluctance: circuits and component ratings. Inst. Elec. Eng. Proc. B128: 126-136. Ehsani M. 1991 Position Sensor elimination technique for the switched reluctance motor drive. US Patent No. 5,072,166. Ehsani M, Ramani K R 1993 Direct control strategies based ...

  18. Switch on, switch off: stiction in nanoelectromechanical switches

    KAUST Repository

    Wagner, Till J W

    2013-06-13

    We present a theoretical investigation of stiction in nanoscale electromechanical contact switches. We develop a mathematical model to describe the deflection of a cantilever beam in response to both electrostatic and van der Waals forces. Particular focus is given to the question of whether adhesive van der Waals forces cause the cantilever to remain in the \\'ON\\' state even when the electrostatic forces are removed. In contrast to previous studies, our theory accounts for deflections with large slopes (i.e. geometrically nonlinear). We solve the resulting equations numerically to study how a cantilever beam adheres to a rigid electrode: transitions between \\'free\\', \\'pinned\\' and \\'clamped\\' states are shown to be discontinuous and to exhibit significant hysteresis. Our findings are compared to previous results from linearized models and the implications for nanoelectromechanical cantilever switch design are discussed. © 2013 IOP Publishing Ltd.

  19. Multi-anode wire straw tube tracker

    International Nuclear Information System (INIS)

    Oh, S.H.; Ebenstein, W.L.; Wang, C.W.

    2011-01-01

    We report on a test of a straw tube detector design having several anode (sense) wires inside a straw tube. The anode wires form a circle inside the tube and are read out independently. This design could solve several shortcomings of the traditional single wire straw tube design such as double hit capability and stereo configuration.

  20. Screened anode N/sub 2/ laser

    Energy Technology Data Exchange (ETDEWEB)

    Sabry, M.M.F.

    1985-01-01

    An experimental study of the effect of screening the discharge channel on the output energy is presented. It has been found that a screened anode nitrogen laser generates higher output energy than that of a screened cathode, and also higher than that when both cathode and anode are unshielded at higher pressures.

  1. Ultrasound-assisted anodization of aluminum in oxalic acid

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Rong; Jiang Kaiming [Department of Physics, Shanghai Maritime University, 1550 Pudong Avenue, Shanghai 200135 (China); Zhu Yun [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050 (China); Qi Haiyang [Department of Physics, Shanghai Maritime University, 1550 Pudong Avenue, Shanghai 200135 (China); Ding Guqiao, E-mail: gqding@mail.sim.ac.cn [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050 (China)

    2011-10-15

    Porous anodic alumina is an important nanoscale template for fabrication of various nanostructures. We report a new ultrasound-assisted anodization process in oxalic acid. Under the continuous irradiation of ultrasound, the one-step-anodized sample has a smooth and clean surface, and two-step-anodization brings ordered porous anodic alumina with higher growth rate of 52 {mu}m/h. The ultrasound applied during the anodization can clean the surface and enhance the nanopore growth since it can accelerate the oxide dissolving on the electrolyte/oxide interface. The ultrasound-assisted anodization may be utilized for other anodizations.

  2. Which ureteral access sheath is compatible with your flexible ureteroscope?

    Science.gov (United States)

    Al-Qahtani, Saeed M; Letendre, Julien; Thomas, Alexandre; Natalin, Ricardo; Saussez, Thibaud; Traxer, Olivier

    2014-03-01

    Our aim is to evaluate different ureteral access sheaths (UASs), which are available in the international market and their compatibility with different available flexible ureteroscopes (F-URSs) to help the urologist choose the proper ureteral access sheath for his or her endoscope before commencing the procedure. A total of 21 UASs and 12 F-URSs were evaluated. Measurements were obtained in French (F) units considering different characteristics for each UAS and each F-URS. Insertion test without friction between F-URS and UAS was considered as a successful test and was referred as (YES). All UASs and F-URSs were successfully submitted to the insertion test. All F-URSs that were inserted into UASs without friction had an internal diameter of at least 12F. Different lengths of UAS did not influence the test outcome. This study was able to establish a correlation table between different UASs and different flexible ureteroscopes. As of now, the 12/14F UAS is considered the universal UAS that accepts all F-URSs that are available in the endourology field. Nevertheless, we are expecting a significant change with the new standard size 10/12F UAS as well as huge advances in minimizing the size of different endoscopes.

  3. Measure Guideline: Guidance on Taped Insulating Sheathing Drainage Planes

    Energy Technology Data Exchange (ETDEWEB)

    Grin, A.; Lstiburek, J.

    2014-09-01

    This guide provides information and recommendations to the following groups: insulation contractors; general contractors; builders; home remodelers; mechanical contractors; and homeowners, as a guide to the work that needs to be done. The order of work completed during home construction and retrofit improvements is important. Health and safety issues must be addressed first and are more important than durability issues. And durability issues are more important than saving energy. Not all techniques can apply to all houses. Special conditions will require special action. Some builders or homeowners will wish to do more than the important but basic retrofit strategies outlined by this guide. The following are best practice and product recommendations from the interviewed contractors and homebuilders who collectively have a vast amount of experience. Three significant items were discussed with the group which are required to make taped insulating sheathing a simple, long term, and durable drainage plane: 1. Horizontal joints should be limited or eliminated wherever possible; 2. Where a horizontal joint exists use superior materials; 3. Frequent installation inspection and regular trade training are required to maintain proper installation. Section 5 of this measure guideline contains the detailed construction procedure for the three recommended methods to effectively seal the joints in exterior insulating sheathing to create a simple, long term, and durable drainage plane.

  4. Discharge modes at the anode of a vacuum arc

    International Nuclear Information System (INIS)

    Miller, H.C.

    1982-01-01

    The two most common anode modes in a vacuum arc are the low current mode, where the anode is basically inert; and the high current mode with a fully developed anode spot. This anode spot is very bright, has a temperature near the boiling point of the anode material, and is a copious source of vapor and energetic ions. However, other anode modes can exist. A low current vacuum arc with electrodes of readily sputterable material will emit a flux of sputtered atoms from the anode. An intermediate currents an anode footpoint can form. This footpoint is luminous, but much cooler than a true anode spot. Finally, a high current mode can exist where several small anode spots are present instead of a single large anode spot

  5. Understanding anode and cathode behaviour in high-pressure discharge lamps

    Science.gov (United States)

    Flesch, P.; Neiger, M.

    2005-09-01

    High-intensity discharge (HID) lamps have widespread and modern areas of application including general lighting, video/movie projection (e.g. UHP lamp), street/industrial lighting, and automotive headlight lamps (D2/xenon lamp). Even though HID lamps have been known for several decades now, the important plasma-electrode interactions are still not well understood. Because HID lamps are usually operated on ac (electrodes switch alternately from anode to cathode phase), time-dependent simulations including realistic and verified anode and cathode models are essential. Therefore, a recently published investigation of external laser heating of an electrode during anode and cathode phase in an operating HID lamp [28] provided the basis for our present paper. These measurements revealed impressive influences of the external laser heating on electrode fall voltage and electrode temperature. Fortunately, the effects are very different during anode and cathode phase. Thus, by comparing the experimental findings with results from our numerical simulations we can learn much about the principles of electrode behaviour and explain in detail the differences between anode and cathode phase. Furthermore, we can verify our model (which includes plasma column, hot plasma spots in front of the electrodes, constriction zones and near-electrode non-local thermal equilibrium-plasma as well as anode and cathode) that accounts for all relevant physical processes concerning plasma, electrodes and interactions between them. Moreover, we investigate the influence of two different notions concerning ionization and recombination in the near electrode plasma on the numerical results. This improves our physical understanding of near-electrode plasma likewise and further increases the confidence in the model under consideration. These results are important for the understanding and the further development of HID lamps which, due to their small dimensions, are often experimentally inaccessible

  6. Switch mode power supply

    International Nuclear Information System (INIS)

    Kim, Hui Jun

    1993-06-01

    This book concentrates on switch mode power supply. It has four parts, which are introduction of switch mode power supply with DC-DC converter such as Buck converter boost converter, Buck-boost converter and PWM control circuit, explanation for SMPS with DC-DC converter modeling and power mode control, resonance converter like resonance switch, converter, multi resonance converter and series resonance and parallel resonance converters, basic test of SMPS with PWM control circuit, Buck converter, Boost converter, flyback converter, forward converter and IC for control circuit.

  7. BROOKHAVEN: Switched power

    International Nuclear Information System (INIS)

    Anon.

    1989-01-01

    Hosted by Brookhaven's Center for Accelerator Physics, a recent workshop on switched power techniques attracted a group of specialists to Shelter Island, New York, location of several important physics meetings, including the famous 1947 sessions which helped mould modern quantum electrodynamics. The current interest in switched power stemmed from a series of papers by W. Willis of CERN, starting in 1984. The idea is for stored electrical energy to be suddenly switched on to a transmission line, producing a very short (about 10 ps) electromagnetic pulse in a region traversed by a particle beam

  8. Electromechanical magnetization switching

    Energy Technology Data Exchange (ETDEWEB)

    Chudnovsky, Eugene M. [Department of Physics and Astronomy, Lehman College and Graduate School, The City University of New York, 250 Bedford Park Boulevard West, Bronx, New York 10468-1589 (United States); Jaafar, Reem [Department of Mathematics, Engineering and Computer Science, LaGuardia Community College, The City University of New York, 31-10 Thomson Avenue, Long Island City, New York 11101 (United States)

    2015-03-14

    We show that the magnetization of a torsional oscillator that, in addition to the magnetic moment also possesses an electrical polarization, can be switched by the electric field that ignites mechanical oscillations at the frequency comparable to the frequency of the ferromagnetic resonance. The 180° switching arises from the spin-rotation coupling and is not prohibited by the different symmetry of the magnetic moment and the electric field as in the case of a stationary magnet. Analytical equations describing the system have been derived and investigated numerically. Phase diagrams showing the range of parameters required for the switching have been obtained.

  9. Electromechanical magnetization switching

    International Nuclear Information System (INIS)

    Chudnovsky, Eugene M.; Jaafar, Reem

    2015-01-01

    We show that the magnetization of a torsional oscillator that, in addition to the magnetic moment also possesses an electrical polarization, can be switched by the electric field that ignites mechanical oscillations at the frequency comparable to the frequency of the ferromagnetic resonance. The 180° switching arises from the spin-rotation coupling and is not prohibited by the different symmetry of the magnetic moment and the electric field as in the case of a stationary magnet. Analytical equations describing the system have been derived and investigated numerically. Phase diagrams showing the range of parameters required for the switching have been obtained

  10. JUNOS Enterprise Switching

    CERN Document Server

    Reynolds, Harry

    2009-01-01

    JUNOS Enterprise Switching is the only detailed technical book on Juniper Networks' new Ethernet-switching EX product platform. With this book, you'll learn all about the hardware and ASIC design prowess of the EX platform, as well as the JUNOS Software that powers it. Not only is this extremely practical book a useful, hands-on manual to the EX platform, it also makes an excellent study guide for certification exams in the JNTCP enterprise tracks. The authors have based JUNOS Enterprise Switching on their own Juniper training practices and programs, as well as the configuration, maintenanc

  11. Dusty Plasma Modeling of the Fusion Reactor Sheath Including Collisional-Radiative Effects

    International Nuclear Information System (INIS)

    Dezairi, Aouatif; Samir, Mhamed; Eddahby, Mohamed; Saifaoui, Dennoun; Katsonis, Konstantinos; Berenguer, Chloe

    2008-01-01

    The structure and the behavior of the sheath in Tokamak collisional plasmas has been studied. The sheath is modeled taking into account the presence of the dust 2 and the effects of the charged particle collisions and radiative processes. The latter may allow for optical diagnostics of the plasma.

  12. An analytical investigation: Effect of solar wind on lunar photoelectron sheath

    Science.gov (United States)

    Mishra, S. K.; Misra, Shikha

    2018-02-01

    The formation of a photoelectron sheath over the lunar surface and subsequent dust levitation, under the influence of solar wind plasma and continuous solar radiation, has been analytically investigated. The photoelectron sheath characteristics have been evaluated using the Poisson equation configured with population density contributions from half Fermi-Dirac distribution of the photoemitted electrons and simplified Maxwellian statistics of solar wind plasma; as a consequence, altitude profiles for electric potential, electric field, and population density within the photoelectron sheath have been derived. The expression for the accretion rate of sheath electrons over the levitated spherical particles using anisotropic photoelectron flux has been derived, which has been further utilized to characterize the charging of levitating fine particles in the lunar sheath along with other constituent photoemission and solar wind fluxes. This estimate of particle charge has been further manifested with lunar sheath characteristics to evaluate the altitude profile of the particle size exhibiting levitation. The inclusion of solar wind flux into analysis is noticed to reduce the sheath span and altitude of the particle levitation; the dependence of the sheath structure and particle levitation on the solar wind plasma parameters has been discussed and graphically presented.

  13. New Method to Analyse the Cement Sheath Integrity During the Volume Fracturing of Shale Gas

    Directory of Open Access Journals (Sweden)

    Mingtao Fan

    2018-03-01

    Full Text Available Accurate prediction of the hoop stress distribution of the cement sheath and its variation regularities during volume hydraulic fracturing in shale formations is of great significance for maintaining the wellbore integrity of shale gas horizontal wells. A finite element model of casing-cement sheath-formation system (CCFS coupling between stresses and temperature was established through a staged finite element method based on the elastic anisotropy of shale. With this new model, the effects of operation parameters and formation mechanical property changes on the cement sheath hoop stress during the multi-stage hydraulic fracturing process were analyzed, and the results were compared with the conventional model. The results revealed that the increase of the temperature of the fracturing fluid could reduce the hoop stress of the cement sheath, which decreased gradually with the decreasing elastic modulus of the cement sheath, and eventually changed to compressive stress from tensile stress. The hoop tensile stress of the cement sheath increases first and then tends to decrease with the increasing internal casing pressure, the larger the local formation stress, the smaller the pore pressure and the smaller the hoop tensile stress of the cement sheath it preforms. The findings of this paper are of great guiding significance to the research of the cement sheath stress variations during volume fracturing in shale formations and to the optimization of fracturing design.

  14. 30 CFR 75.700 - Grounding metallic sheaths, armors, and conduits enclosing power conductors.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Grounding metallic sheaths, armors, and conduits enclosing power conductors. 75.700 Section 75.700 Mineral Resources MINE SAFETY AND HEALTH... Grounding § 75.700 Grounding metallic sheaths, armors, and conduits enclosing power conductors. [Statutory...

  15. 30 CFR 77.700 - Grounding metallic sheaths, armors, and conduits enclosing power conductors.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Grounding metallic sheaths, armors, and conduits enclosing power conductors. 77.700 Section 77.700 Mineral Resources MINE SAFETY AND HEALTH... AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Grounding § 77.700 Grounding metallic sheaths, armors...

  16. Measurement of sheath thickness by lining out grooves in the Hall-type stationary plasma thrusters

    International Nuclear Information System (INIS)

    Yu Daren; Wu Zhiwen; Ning Zhongxi; Wang Xiaogang

    2007-01-01

    Using grooves created along the axial direction of the discharge channel, a method for measuring sheath thickness in Hall-type stationary plasma thrusters has been developed. By distorting the wall surface using these grooves, it is possible to numerically study the effect of the wall surface on the sheath and near wall conductivity. Monte Carlo method is applied to calculate the electron temperature variation with different groove depths. The electron dynamic process in the plasma is described by a test particle method with the electron randomly entering the sheath from the discharge channel and being reflected back. Numerical results show that the reflected electron temperature is hardly affected by the wall surface if the groove depth is much less than the sheath thickness. On the other hand, the reflected electron temperature increases if the groove depth is much greater than the sheath thickness. The reflected electron temperature has a sharp jump when the depth of groove is on the order of the sheath thickness. The simulation is repeated with different sheath thicknesses and the results are the same. Therefore, a diagnosis mean of the sheath thickness can be developed based on the method. Also the simulation results are in accord with the experimental data. Besides, the measurement method may be applicable to other plasma device with similar orthogonal steady state electrical and magnetic fields

  17. Perovskites synthesis to SOFC anodes

    International Nuclear Information System (INIS)

    Wendler, L.P.; Chinelatto, A.L.; Chinelatto, A.S.A.; Ramos, K.

    2012-01-01

    Perovskite structure materials containing lanthanum have been widely applied as solid oxide fuel cells (SOFCs) electrodes, due to its electrical properties. Was investigated the obtain of the perovskite structure LaCr 0,5 Ni 0,5 O 3 , by Pechini method, and its suitability as SOFC anode. The choice of this composition was based on the stability provided by chromium and the catalytic properties of nickel. After preparing the resins, the samples were calcined at 300 deg C, 600 deg C, 700 deg C and 850 deg C. The resulting powders were characterized by X-ray diffraction to determine the existing phases. Furthermore, were performed other analysis, like X-ray fluorescence, He pycnometry, specific surface area by BET isotherm and scanning electronic microscopy (author)

  18. [Early reactive changes of myelin sheath in the area of myelin sheath gaps (nodes of Ranvier) in nerve fibers (a supravital study)].

    Science.gov (United States)

    Sotnikov, O S; Kokurina, T N; Solov'eva, I A; Sergeeva, S S

    2011-01-01

    Using the inverted phase contrast microscope, the supravital study of structural dynamics of single myelin sheath gaps (nodes of Ranvier) of isolated frog myelin nerve fibers was performed after mechanical injury and in the medium with the decreased ion force under the conditions which induce, in electrophysiological experiments, the expression of the axolemmal K+-channels in the paranodal area. Videorecording has shown that within this area the myelin sheath stratification appeared that was associated with the swelling of Schwann cell cytoplasm enclosed in the terminal membranous loops of myelin. An increase of the degree of stratification of the lamellar myelin complexes make them invisible in the light microscope; therefore, it is not the translocation of the myelin sheath from the node cleft that is recorded, as many authors believed, but a shift of only the visible border of the compact, yet unstratified myelin sheath. Hence, the removal of myelin (demyelination) was absent, and the electrophysiological effect can be accounted for by a significant fall of electrical resistance in paranodal area as a result of swelling of terminal loops and stratification of the myelin sheath. Preparations examination also revealed a decrease of the axonal diameter in, which is proportional to swelling of the myelin sheath terminal parts. Since the outer fiber diameter did not change, it can be concluded that the process observed is the result of swelling of the Schwann cell cytoplasm due to the axoplasm water fraction which may be a peculiar process of axo-glial interactions.

  19. Characteristic of plasma sheath in the presence of secondary electron emission and negative ions

    International Nuclear Information System (INIS)

    Zhao Xiaoyun; Ni Zhixiang; He Juan; Liu Jinyuan

    2009-01-01

    The model of the non-collision plasma sheath is developed in the presence of secondary electron emission(SEE) and negative ions. The effect is discussed of the secondary electron emission and negative ions on the sheath of a one-dimensional stationary plasma. The interaction between secondary electrons and negative ions is also analyzed. It is found that the increase of SEE coefficient and negative ion content in the plasma will reduce the width of plasma sheath. If the SEE coefficient is larger than the critical emission coefficient, the sheath would not only formed by ions. In the sheath of a multicomponent plasma, the density of negative ions increases when the SEE coefficient enhances,and the critical SEE coefficient will be bigger with the enhancement of negative ions. In addition,the presence of SEE and negative ions would affect the discharge in the plasma and erosion of the wall. (authors)

  20. Fibroma of the tendon sheath of the long head of the biceps tendon

    International Nuclear Information System (INIS)

    Maeseneer, Michel de; Shahabpour, Maryam; Isacker, Tom van; Lenchik, Leon; Caillie, Marie-Astrid van

    2014-01-01

    Fibroma of the tendon sheath is a benign tumor that is less common than giant cell tumor of the tendon sheath. Both tumors may present as a painless, slowly enlarging mass. Radiological findings may be similar for both tumors. Histologically, fibroma of the tendon sheath lacks the hemosiderin-laden macrophages that are typical for giant cell tumor of the tendon sheath. We report on a 49-year-old woman with fibroma of the tendon sheath of the long head of the biceps tendon. In our case, on MR images, we observed band-like hypointense areas centrally in the tumor, mild patchy contrast enhancement, and most importantly, no decrease of signal intensity on gradient echo images. These characteristics reflected histological findings. (orig.)

  1. Fibroma of the tendon sheath of the long head of the biceps tendon

    Energy Technology Data Exchange (ETDEWEB)

    Maeseneer, Michel de; Shahabpour, Maryam [Universitair Ziekenhuis Brussel, Department of Radiology, Brussels (Belgium); Isacker, Tom van [Sint-Lucas Hospital, Department of Orthopedic Surgery, Brugge (Belgium); Lenchik, Leon [Wake Forest School of Medicine, Department of Radiology, Winston Salem, NC (United States); Caillie, Marie-Astrid van [Sint-Lucas Hospital, Department of Pathology, Brugge (Belgium)

    2014-03-15

    Fibroma of the tendon sheath is a benign tumor that is less common than giant cell tumor of the tendon sheath. Both tumors may present as a painless, slowly enlarging mass. Radiological findings may be similar for both tumors. Histologically, fibroma of the tendon sheath lacks the hemosiderin-laden macrophages that are typical for giant cell tumor of the tendon sheath. We report on a 49-year-old woman with fibroma of the tendon sheath of the long head of the biceps tendon. In our case, on MR images, we observed band-like hypointense areas centrally in the tumor, mild patchy contrast enhancement, and most importantly, no decrease of signal intensity on gradient echo images. These characteristics reflected histological findings. (orig.)

  2. The anatomy of the first sacral nerve root sheath shown by computed tomography.

    Science.gov (United States)

    Moore, N R; Dixon, A K; Freer, C E

    1989-08-01

    Analysis of 25 patients with normal computed tomographic appearances at the lumbosacral junction revealed wide variation in the anatomical level at which the first sacral nerve root sheaths were seen emerging from the theca. In nine patients (36%), the S1 nerve root sheaths were first recognized at the level of the lumbosacral disc. In 14 patients (56%), the sheaths emerged cranial to the disc; it is possible that these patients may be more prone to neurological complications related to disc or facet joint disease, especially if the sheath is laterally sited within the lateral recess. Conversely, that minority of patients (two, 8%) in whom the root sheaths emerge caudal to the disc level may be relatively protected from neurological complications.

  3. uv preilluminated gas switches

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, L.P.; Orham, E.L.; Stowers, I.F.; Braucht, J.R.

    1980-06-03

    We have designed, built, and characterized uv preilluminated gas switches for a trigger circuit and a low inductance discharge circuit. These switches have been incorporated into a 54 x 76 x 150 cm pulser module to produce a 1 Ma output current rising at 5 x 10/sup 12/ amps/sec with 1 ns jitter. Twenty such modules will be used on the Nova Inertial Confinement Fusion Laser System for plasma retropulse shutters.

  4. Switching power supply filter

    Science.gov (United States)

    Kumar, Prithvi R. (Inventor); Abare, Wayne (Inventor)

    1989-01-01

    A filter for a switching power supply. The filter includes a common mode inductor with coil configurations allowing differential mode current from a dc source to pass through but attenuating common mode noise from the power supply so that the noise does not reach the dc source. The invention also includes the use of feed through capacitors at the switching power supply input terminals to provide further high-frequency noise attenuation.

  5. uv preilluminated gas switches

    International Nuclear Information System (INIS)

    Bradley, L.P.; Orham, E.L.; Stowers, I.F.; Braucht, J.R.

    1980-01-01

    We have designed, built, and characterized uv preilluminated gas switches for a trigger circuit and a low inductance discharge circuit. These switches have been incorporated into a 54 x 76 x 150 cm pulser module to produce a 1 Ma output current rising at 5 x 10 12 amps/sec with 1 ns jitter. Twenty such modules will be used on the Nova Inertial Confinement Fusion Laser System for plasma retropulse shutters

  6. Photonics in switching

    CERN Document Server

    Midwinter, John E; Kelley, Paul

    1993-01-01

    Photonics in Switching provides a broad, balanced overview of the use of optics or photonics in switching, from materials and devices to system architecture. The chapters, each written by an expert in the field, survey the key technologies, setting them in context and highlighting their benefits and possible applications. This book is a valuable resource for those working in the communications industry, either at the professional or student level, who do not have extensive background knowledge or the underlying physics of the technology.

  7. Benign and malignant neurogenic tumors of nerve sheath origin on FDG PET

    Energy Technology Data Exchange (ETDEWEB)

    Yun, M. J.; Go, D. H.; Yoo, Y. H.; Shin, K. H.; Lee, J. D [College of Medicine, Yonsei University, Seoul (Korea, Republic of)

    2004-07-01

    The differentiation between benign and malignant nerve sheath tumors is difficult based on conventional radiological imaging. This study was undertaken to investigate the value of FDG PET in distinguishing benign from malignant neurogenic tumors of nerve sheath origin. We performed a retrospective review of the medical record to select patients with nerve sheath tumors who had underdone FDG PET imaging. Fifteen patients (7F: 8M) with benign or malignant nerve sheath tumors were included in this study. Of the 15 patients, 9 were diagnosed with the known neurofibromatosis type I. A total of 19 nerve sheath tumors were included from the 15 patients. All patients had undergone FDG PET to evaluate for malignant potential of the known lesions. Images of FDG PET were semi-quantitatively analyzed and a region of interest (ROI) was placed over the area of the maximum FDG uptake and an average standardized uptake value was taken for final analysis. There were 5 malignant peripheral nerve sheath tumors, 5 schwannomas, and 9 neurofibromas. The mean SUV was 2 (ranged from 1.6 to 3.3) for schwannomas, 1.3 (0.7 to 2.5) for neurofibromas, and 8.4 (4.6 to 12.2) for malignant peripheral nerve sheath tumors. Of 14 benign tumors, all except one schwannoma showed a SUV less than 3. When a cutoff SUV of 4 was used to differentiate the nerve sheath tumors, all tumors were correctly classified as benign or malignant, respectively. Among the 9 patients diagnosed with neurofibromatosis type I. 4 had malignant peripheral nerve sheath tumors and FDG PET accurately detected all the 4 lesions with malignant transformation. According to our results, FDG PET seems to have a great potential for accurately characterizing benign versus malignant nerve sheath tumors. It appears to be extremely useful for patients with neurofibromatosis to localize the lesion with malignant transformation.

  8. Benign and malignant neurogenic tumors of nerve sheath origin on FDG PET

    International Nuclear Information System (INIS)

    Yun, M. J.; Go, D. H.; Yoo, Y. H.; Shin, K. H.; Lee, J. D

    2004-01-01

    The differentiation between benign and malignant nerve sheath tumors is difficult based on conventional radiological imaging. This study was undertaken to investigate the value of FDG PET in distinguishing benign from malignant neurogenic tumors of nerve sheath origin. We performed a retrospective review of the medical record to select patients with nerve sheath tumors who had underdone FDG PET imaging. Fifteen patients (7F: 8M) with benign or malignant nerve sheath tumors were included in this study. Of the 15 patients, 9 were diagnosed with the known neurofibromatosis type I. A total of 19 nerve sheath tumors were included from the 15 patients. All patients had undergone FDG PET to evaluate for malignant potential of the known lesions. Images of FDG PET were semi-quantitatively analyzed and a region of interest (ROI) was placed over the area of the maximum FDG uptake and an average standardized uptake value was taken for final analysis. There were 5 malignant peripheral nerve sheath tumors, 5 schwannomas, and 9 neurofibromas. The mean SUV was 2 (ranged from 1.6 to 3.3) for schwannomas, 1.3 (0.7 to 2.5) for neurofibromas, and 8.4 (4.6 to 12.2) for malignant peripheral nerve sheath tumors. Of 14 benign tumors, all except one schwannoma showed a SUV less than 3. When a cutoff SUV of 4 was used to differentiate the nerve sheath tumors, all tumors were correctly classified as benign or malignant, respectively. Among the 9 patients diagnosed with neurofibromatosis type I. 4 had malignant peripheral nerve sheath tumors and FDG PET accurately detected all the 4 lesions with malignant transformation. According to our results, FDG PET seems to have a great potential for accurately characterizing benign versus malignant nerve sheath tumors. It appears to be extremely useful for patients with neurofibromatosis to localize the lesion with malignant transformation

  9. Wireless Chalcogenide Nanoionic-Based Radio-Frequency Switch

    Science.gov (United States)

    Nessel, James; Miranda, Felix

    2013-01-01

    A new nonvolatile nanoionic switch is powered and controlled through wireless radio-frequency (RF) transmission. A thin layer of chalcogenide glass doped with a metal ion, such as silver, comprises the operational portion of the switch. For the switch to function, an oxidizable electrode is made positive (anode) with respect to an opposing electrode (cathode) when sufficient bias, typically on the order of a few tenths of a volt or more, is applied. This action causes the metal ions to flow toward the cathode through a coordinated hopping mechanism. At the cathode, a reduction reaction occurs to form a metal deposit. This metal deposit creates a conductive path that bridges the gap between electrodes to turn the switch on. Once this conductive path is formed, no further power is required to maintain it. To reverse this process, the metal deposit is made positive with respect to the original oxidizable electrode, causing the dissolution of the metal bridge thereby turning the switch off. Once the metal deposit has been completely dissolved, the process self-terminates. This switching process features the following attributes. It requires very little to change states (i.e., on and off). Furthermore, no power is required to maintain the states; hence, the state of the switch is nonvolatile. Because of these attributes the integration of a rectenna to provide the necessary power and control is unique to this embodiment. A rectenna, or rectifying antenna, generates DC power from an incident RF signal. The low voltages and power required for the nanoionic switch control are easily generated from this system and provide the switch with a novel capability to be operated and powered from an external wireless device. In one realization, an RF signal of a specific frequency can be used to set the switch into an off state, while another frequency can be used to set the switch to an on state. The wireless, miniaturized, and nomoving- part features of this switch make it

  10. CANDU fuel sheath behavior in power ramp conditions

    International Nuclear Information System (INIS)

    Ionescu, S.; Uta, O; Parvan, M.

    2009-01-01

    The purpose of this work is to determine by post-irradiation examination, the behavior of CANDU domestic fuel, irradiated in TRIGA14 reactor MW(th), into a multiple / various power ramp test. After testing, the fuel rods have been examined in the hot cells using post-irradiation examination (PIE) techniques such as: visual inspection and photography, eddy current testing, profilometry, gamma scanning, fission gas release and analysis, metallography, ceramography, burn-up determination by mass spectrometry, mechanical testing. This paper describes the PIE results from one out of six fuel rods. The PIE results concerning the integrity, dimensional changes, oxidation, hydriding and mechanical properties of the sheath, the fission-products activity distribution in the fuel column, the pressure, volume and composition of the fission gas, the burn-up, the isotopic composition and structural changes of the fuel are used to confirm the security, reliability, fuel performance, and also for Romanian CANDU fuel development program. (authors)

  11. Giant Cell Tumour of Tendon Sheath Masquerading As Trigger Finger

    Directory of Open Access Journals (Sweden)

    N Rahimawati

    2010-11-01

    Full Text Available We report a case of a 59-year-old female who presented in the general orthopaedic clinic with triggering of her right middle finger. She did not respond to conventional treatment methods; subsequently she underwent surgical open release under local anaesthesia. Five months postoperatively, the patient presented with signs and symptoms of acute flexor tenosynovitis, and was thought to have a postoperative infection. Re-examination by a hand surgeon raised the possibility of a different aetiology. Based on clinical findings and response to initial treatment, giant cell tumour of the flexor tendon sheath was suspected and later confirmed following surgical biopsy. A high index of suspicion and knowledge of the variegated presentations of giant cell tumour in the hand are beneficial in these types of cases.

  12. Malignant peripheral nerve sheath tumor arising from solitary neurofibroma

    Directory of Open Access Journals (Sweden)

    Pei-I Chung

    2014-09-01

    Full Text Available Malignant peripheral nerve sheath tumors (MPNSTs are rare sarcomas that are strongly associated with neurofibromatosis type I (NF-1. We describe a 71-year-old woman with no stigmata of neurofibromatosis, who presented with recurrent subcutaneous tumor on her left upper back. She received two excisional biopsies on the back of her trunk at our hospital and both pathology reports revealed neurofibromas. Three years after the last skin biopsy, a rapidly growing subcutaneous tumor emerged at the same site. This tumor was totally resected and the histopathology showed an ill-defined tumor in the dermis and subcutaneous tissue. The tumor was composed of spindle cells in a myxoid stroma with a transition from the area of typical neurofibroma to the hypercellular area. The hypercellular area consisted of atypical, hyperchromatic spindled cells with frequent mitotic figures. She was therefore diagnosed with MPNST.

  13. Primary malignant peripheral nerve sheath tumor at unusual location

    Directory of Open Access Journals (Sweden)

    Souvagya Panigrahi

    2013-01-01

    Full Text Available Malignant peripheral nerve sheath tumor (MPNST is a rare soft tissue sarcoma. Most arise in association with major nerve trunks. Their most common anatomical sites are the proximal portions of the upper and lower extremities and the trunk. MPNSTs have rarely been reported in literature to occur in other unusual body parts. We review all such cases reported till now in terms of site of origin, surgical treatment, adjuvant therapy and outcome and shortly describe our experience with two of these cases. Both of our case presented with lump at unusual sites resembling neurofibroma, one at orbitotemporal area and other in the paraspinal region with characteristic feature of neurofibroma with the exception that both had very short history of progression. They underwent gross total removal of the tumor with adjuvant radiotherapy postoperatively. At 6-month follow-up both are doing well with no evidence of recurrence.

  14. Experiments on Alignment of Dust Particles in Plasma Sheath

    International Nuclear Information System (INIS)

    Samarian, A.A.; Vladimirov, S.V.; James, B.W.

    2005-01-01

    Here, we report an experimental investigation of the stability of vertical and horizontal confinement of dust particles levitated in an rf sheath. The experiments were carried out in argon plasma with micron-sized dust particles. Changes of particle arrangement were triggered by changing the discharge parameters, applying an additional bias to the confining electrode and by laser beam. The region where the transition was triggered by changes of discharge parameters and the transition from horizontal to vertical alignment has been found to be more pronounced than for the reverse transition. A clear hysteretic effect was observed for transitions triggered by changes of the confining voltage. A vertical alignment occurs in a system of two dust horizontally arranged particles with the decrease of the particle separation. This disruption is attributed to the formation of the common ion wake in the system

  15. Cutaneous benign epithelioid peripheral nerve sheath tumour: A rare entity

    Directory of Open Access Journals (Sweden)

    Anuradha CK Rao

    2013-01-01

    Full Text Available Benign epithelioid peripheral nerve sheath tumor, a rare entity is an umbrella term describing benign, neural origin tumors with epithelioid morphology. Clinically indistinguishable from other benign cutaneous lesions, histopathology offers the only source of accurate diagnosis. Morphologic mimics include many benign and malignant soft tissue lesions. Besides a predominant epithelioid component, the lesion can also show a fair share of spindle cells. A circumscribed nodular tumour of low mitotic activity, it often exhibits areas resembling schwannoma or neurofibroma. An awareness of this entity and its varied morphological aspects helps to arrive at the correct diagnosis and hence avoid unnecessary extensive surgical procedures. This case presents features of this benign tumor which occurred in a 47 years old man.

  16. Optical switching systems using nanostructures

    DEFF Research Database (Denmark)

    Stubkjær, Kristian

    2004-01-01

    High capacity multiservice optical networks require compact and efficient switches. The potential benefits of optical switch elements based on nanostructured material are reviewed considering various material systems.......High capacity multiservice optical networks require compact and efficient switches. The potential benefits of optical switch elements based on nanostructured material are reviewed considering various material systems....

  17. Understanding and Supporting Window Switching

    NARCIS (Netherlands)

    Tak, S.

    2011-01-01

    Switching between windows on a computer is a frequent activity, but finding and switching to the target window can be inefficient. This thesis aims to better un-derstand and support window switching. It explores two issues: (1) the lack of knowledge of how people currently interact with and switch

  18. Effect of anodization on corrosion behaviour and biocompatibility of ...

    Indian Academy of Sciences (India)

    Pores of some anodized samples are sealed by exposing the anodized surface in boiling water. Corrosion behaviour of the anodized specimen is studied in Ringer's solution at 30 ± 2 °C, using electrochemical impedance and cyclic polarization technique. Biocompatibility of the anodized surface is accessed using MG63 ...

  19. File list: InP.Neu.05.AllAg.Nerve_Sheath_Neoplasms [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  1. File list: NoD.Neu.10.AllAg.Nerve_Sheath_Neoplasms [Chip-atlas[Archive

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  6. File list: InP.Neu.20.AllAg.Nerve_Sheath_Neoplasms [Chip-atlas[Archive

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  7. Low inductance gas switching.

    Energy Technology Data Exchange (ETDEWEB)

    Chavez, Ray; Harjes, Henry Charles III; Wallace, Zachariah; Elizondo, Juan E.

    2007-10-01

    The laser trigger switch (LTS) is a key component in ZR-type pulsed power systems. In ZR, the pulse rise time through the LTS is > 200 ns and additional stages of pulse compression are required to achieve the desired <100 ns rise time. The inductance of the LTS ({approx}500nH) in large part determines the energy transfer time through the switch and there is much to be gained in improving system performance and reducing system costs by reducing this inductance. The current path through the cascade section of the ZR LTS is at a diameter of {approx} 6-inches which is certainly not optimal from an inductance point of view. The LTS connects components of much greater diameter (typically 4-5 feet). In this LDRD the viability of switch concepts in which the diameter of cascade section is greatly increased have been investigated. The key technical question to be answered was, will the desired multi-channel behavior be maintained in a cascade section of larger diameter. This LDRD proceeded in 2 distinct phases. The original plan for the LDRD was to develop a promising switch concept and then design, build, and test a moderate scale switch which would demonstrate the key features of the concept. In phase I, a switch concept which meet all electrical design criteria and had a calculated inductance of 150 nH was developed. A 1.5 MV test switch was designed and fabrication was initiated. The LDRD was then redirected due to budgetary concerns. The fabrication of the switch was halted and the focus of the LDRD was shifted to small scale experiments designed to answer the key technical question concerning multi-channel behavior. In phase II, the Multi-channel switch test bed (MCST) was designed and constructed. The purpose of MCST was to provide a versatile, fast turn around facility for the study the multi-channel electrical breakdown behavior of a ZR type cascade switch gap in a parameter space near that of a ZR LTS. Parameter scans on source impedance, gap tilt, gap spacing and

  8. Proto-I switching and diode studies

    International Nuclear Information System (INIS)

    Prestwich, K.R.; Miller, P.A.; McDaniel, D.H.; Poukey, J.W.; Widner, M.M.; Goldstein, S.A.

    1975-01-01

    Proto-I is a 3 MV, 800 kA, 24 ns electron beam accelerator that is under development at Sandia Laboratories. It represents an initial effort to develop a scalable technology that is applicable to accelerators for electron beam driven, inertial confinement fusion studies. Energy is supplied to each of the two diodes from six oil-dielectric Blumlein transmission lines (PFL) operating in parallel. A Marx generator charges three intermediate storage, water-dielectric capacitors which subsequently transfer the stored energy to the PFL. The discharge of the PFL is initiated by the simultaneous closure of 12 triggered oil-dielectric rail switches. Data will be presented on the operation of these multichannel switches. The two diodes have a common anode. Cathode diameters can be varied from 10 to 60 cm. Results of initial diode experiments and comparisons with theory are discussed. Plasma filled diode experiments are also reported, indicating pinch collapse velocities in excess of 10 9 cm/s

  9. Anodic titania films as anode materials for lithium ion batteries

    International Nuclear Information System (INIS)

    Lindsay, M.J.; Blackford, M.G.; Attard, D.J.; Luca, V.; Skyllas-Kazacos, M.; Griffith, C.S.

    2007-01-01

    Titania thin films were prepared through the anodisation of titanium metal in a 1.0 M sulphuric acid solution at 80 o C utilising a series of pulsed dc constant currents of increasing magnitude. Films were then tested as a potential anode material for lithium batteries using a variety of techniques. Electrochemical testing revealed that the films (3.8 cm 2 ) offered good rate capabilities affording a constant capacity of 48 μAh for a constant current of 10 μA which decreased to 25 μAh on increasing the current to 1250 μA. Cyclic voltammetry was conducted over a range of scan rates from which capacitive currents were examined and rate constants, transfer coefficients and diffusion coefficients calculated. Electrochemical impedance spectroscopy was conducted over six potentials in the range 0.1-2.7 V with the experimental data successfully modelled using an equivalent circuit with the notation R(Q(RW))C. TEM observation of focussed ion beam milled cross-sections showed significant structural differences between the as-anodised film and those cycled in a lithium battery. Raman spectroscopy showed that the films had an anatase character that transformed into an unidentified lithium-containing, titanate phase on cycling. Based on a film thickness of 100 nm, and assuming density of 4 g cm -3 such films offered a stable capacity of 316 mAh g -1

  10. Structural Engineering of Nanoporous Anodic Alumina Photonic Crystals by Sawtooth-like Pulse Anodization.

    Science.gov (United States)

    Law, Cheryl Suwen; Santos, Abel; Nemati, Mahdieh; Losic, Dusan

    2016-06-01

    This study presents a sawtooth-like pulse anodization approach aiming to create a new type of photonic crystal structure based on nanoporous anodic alumina. This nanofabrication approach enables the engineering of the effective medium of nanoporous anodic alumina in a sawtooth-like manner with precision. The manipulation of various anodization parameters such as anodization period, anodization amplitude, number of anodization pulses, ramp ratio and pore widening time allows a precise control and fine-tuning of the optical properties (i.e., characteristic transmission peaks and interferometric colors) exhibited by nanoporous anodic alumina photonic crystals (NAA-PCs). The effect of these anodization parameters on the photonic properties of NAA-PCs is systematically evaluated for the establishment of a fabrication methodology toward NAA-PCs with tunable optical properties. The effective medium of the resulting NAA-PCs is demonstrated to be optimal for the development of optical sensing platforms in combination with reflectometric interference spectroscopy (RIfS). This application is demonstrated by monitoring in real-time the formation of monolayers of thiol molecules (11-mercaptoundecanoic acid) on the surface of gold-coated NAA-PCs. The obtained results reveal that the adsorption mechanism between thiol molecules and gold-coated NAA-PCs follows a Langmuir isotherm model, indicating a monolayer sorption mechanism.

  11. Macrokinetic relationships between anodic processes in chlorine electrolysis on ruthenium-titanium oxide anodes

    International Nuclear Information System (INIS)

    Evdokimov, S.V.

    1999-01-01

    Effect of porosity on kinetics of the main (chlorine evolution) and side (oxygen evolution and anodic dissolution of ruthenium dioxide) reactions for chlorine electrolysis conditions has been analyzed. Making allowance for chlorine hydrolysis secondary reaction, the distribution of chlorine concentration, solution pH and current densities of the main and side processes over the porous anode depth, have been found. It is shown that solution acidification in the anode pores due to chlorine hydrolysis can bring about replacement of oxygen evolution and ruthenium dioxide dissolution side reactions toward the porous anode external sides thus affecting its selectivity and corrosion resistance [ru

  12. Electrometallurgy of copper refinery anode slimes

    Science.gov (United States)

    Scott, J. D.

    1990-08-01

    High-selenium copper refinery anode slimes form two separate and dynamically evolving series of compounds with increasing electrolysis time. In one, silver is progressively added to non-stoichiometric copper selenides, both those originally present in the anode and those formed subsequently in the slime layer, and in the other, silver-poor copper selenides undergo a dis-continuous crystallographic sequence of anodic-oxidative transformations. The silver-to-selenium molar ratio in the as-cast anode and the current density of electrorefining can be used to construct predominance diagrams for both series and, thus, to predict the final bulk “mineralogy” of the slimes. Although totally incorrect in detail, these bulk data are sufficiently accurate to provide explanations for several processing problems which have been experienced by Kidd Creek Division, Falconbridge Ltd., in its commercial tankhouse. They form the basis for a computer model which predicts final cathode quality from chemical analyses of smelter feed.

  13. On the mechanisms of cation injection in conducting bridge memories: The case of HfO2 in contact with noble metal anodes (Au, Cu, Ag)

    International Nuclear Information System (INIS)

    Saadi, M.; Gonon, P.; Vallée, C.; Mannequin, C.; Bsiesy, A.; Grampeix, H.; Jalaguier, E.; Jomni, F.

    2016-01-01

    Resistance switching is studied in HfO 2 as a function of the anode metal (Au, Cu, and Ag) in view of its application to resistive memories (resistive random access memories, RRAM). Current-voltage (I-V) and current-time (I-t) characteristics are presented. For Au anodes, resistance transition is controlled by oxygen vacancies (oxygen-based resistive random access memory, OxRRAM). For Ag anodes, resistance switching is governed by cation injection (Conducting Bridge random access memory, CBRAM). Cu anodes lead to an intermediate case. I-t experiments are shown to be a valuable tool to distinguish between OxRRAM and CBRAM behaviors. A model is proposed to explain the high-to-low resistance transition in CBRAMs. The model is based on the theory of low-temperature oxidation of metals (Cabrera-Mott theory). Upon electron injection, oxygen vacancies and oxygen ions are generated in the oxide. Oxygen ions are drifted to the anode, and an interfacial oxide is formed at the HfO 2 /anode interface. If oxygen ion mobility is low in the interfacial oxide, a negative space charge builds-up at the HfO 2 /oxide interface. This negative space charge is the source of a strong electric field across the interfacial oxide thickness, which pulls out cations from the anode (CBRAM case). Inversely, if oxygen ions migration through the interfacial oxide is important (or if the anode does not oxidize such as Au), bulk oxygen vacancies govern resistance transition (OxRRAM case).

  14. Anodic growth of titanium dioxide nanostructures

    DEFF Research Database (Denmark)

    2010-01-01

    Disclosed is a method of producing nanostructures of titanium dioxide (TiO 2 ) by anodisation of titanium (Ti) in an electrochemical cell, comprising the steps of: immersing a non-conducting substrate coated with a layer of titanium, defined as the anode, in an electrolyte solution...... an electrical contact to the layer of titanium on the anode, where the electrical contact is made in the electrolyte solution...

  15. Features of the photosynthetic tissue in the sheaths of rice (Oryza sativa L.)

    Science.gov (United States)

    Guo, Zhao Wu; He, Qiang; Feng, Deng Hua

    The photosynthesis of rice sheath plays a significant role to furnish rice yield, and it is accounted for 10 to 20% of the final yield. But, limited studies have been done to address this phenomenon and to characterize the features of the photosynthetic tissue in rice sheath. In this paper, a super hybrid rice and a hybrid rice were studied as the experimental materials, and the characteristics of the photosynthetic tissue in rice sheaths were examined by microscopic and super-microscopic observation. The results showed that the photosynthetic tissue of rice sheath was rich in the intact mesophyllous cells full of chloroplasts, grana and thylakoids, which were much the same as those of rice blade. The stomatal density in the outer epidermises of the sheaths was comparable to those in the up- and down-epidermises of the blades. The mesophyllous cells in the sheaths were also rich in chlorophylls, and had the net photosynthetic rate (Pn). Therefore, rice sheath was also full of the intact photosynthetic apparatus similar to those in rice blade, and had capabilities of photosynthesis.

  16. Presheath/sheath model with secondary electron emission from two parallel walls

    International Nuclear Information System (INIS)

    Ahedo, E.

    2002-01-01

    A macroscopic model of the interaction of a plasma with two parallel, electron-emitting walls is presented. Zero Debye-length and total thermalization of the secondary electron emission (SEE) are assumed. The SEE is treated as a free beam within each thin, collisionless sheath, but as part of a single electron population within the presheath. Plasma models with three and two species result in sheath and presheath, respectively. The ion flow at the presheath/sheath transition is sonic, and the sound speed there determines the relation between the temperature of the confined electron populations in sheath and presheath. For the general case of a plasma flowing axially between two annular walls the complete dimensionless solution depends on five parameters. Potential drops in the presheath can be larger than in the sheaths, mainly when charge-saturation is reached in the sheath or for a large effective ion friction in the presheath. The losses of plasma current to the walls are determined totally by the presheath problem, whereas the sheath problem and wall material determine the energy lost by impacting particle. Energy losses change drastically from zero SEE to a SEE yield about 100% when the charge-saturated regime is reached

  17. The collisional capacitive RF sheath and the assumption of a sharp electron edge

    Science.gov (United States)

    Brinkmann, Ralf Peter

    2008-10-01

    The transition from quasi-neutrality to charge depletion is one of the characteristic features of the plasma boundary sheath. It is often described in terms of the so-called step model which assumes a transition point (electron step) where the electron density drops from a value equal to the ion density (in the bulk) to a value of zero (in the sheath). Inserted into Poisson's equation, the step model yields an expression for the field which is realistic deep in the sheath but fails to merge correctly into the ambipolar field of the bulk. This work studies the consequences of that approximation for the example of the collision-dominated, capacitive RF sheath by Lieberman [1]. First, the model is solved exactly, using a relaxation scheme. Then, the step approximation is applied which recovers Lieberman's semi-analytical solution. It is demonstrated that the step approximation induces a spurious divergence of the ion density at the sheath edge and prevents a matching of the sheath model to a bulk model. Integral sheath quantities, on the other hand, like the capacitance or the overall voltage drop, are faithfully reproduced. [1] M. A. Lieberman, IEEE Trans. Plasma Sci. 16, pp. 638-644 (1988).

  18. Verification of high voltage rf capacitive sheath models with particle-in-cell simulations

    Science.gov (United States)

    Wang, Ying; Lieberman, Michael; Verboncoeur, John

    2009-10-01

    Collisionless and collisional high voltage rf capacitive sheath models were developed in the late 1980's [1]. Given the external parameters of a single-frequency capacitively coupled discharge, plasma parameters including sheath width, electron and ion temperature, plasma density, power, and ion bombarding energy can be estimated. One-dimensional electrostatic PIC codes XPDP1 [2] and OOPD1 [3] are used to investigate plasma behaviors within rf sheaths and bulk plasma. Electron-neutral collisions only are considered for collisionless sheaths, while ion-neutral collisions are taken into account for collisional sheaths. The collisionless sheath model is verified very well by PIC simulations for the rf current-driven and voltage-driven cases. Results will be reported for collisional sheaths also. [1] M. A. Lieberman, IEEE Trans. Plasma Sci. 16 (1988) 638; 17 (1989) 338 [2] J. P. Verboncoeur, M. V. Alves, V. Vahedi, and C. K. Birdsall, J. Comp. Phys. 104 (1993) 321 [3] J. P. Verboncoeur, A. B. Langdon and N. T. Gladd, Comp. Phys. Comm. 87 (1995) 199

  19. Considerations in the surgical use of the flexor sheath and pulley system.

    Science.gov (United States)

    Lowrie, A G; Lees, V C

    2014-01-01

    The use of the digital flexor sheath to reconstruct damaged structures in the fingers is an intriguing but under-investigated subject. The sheath is anchored firmly to the phalanges and palmar plates and has well-vascularized outer and synovial inner layers. The middle layer is strong and fibrous and not all of it is required for its main biomechanical function of maintaining the moment arm of the flexor tendons. These characteristics have led to several descriptions of different reconstructive uses. In sheath reconstruction, flaps can be used to repair damaged A2 and A4 pulleys. As an anchor, the sheath is useful for tenodeses and tendon transfers. It has been used in the correction of ulnar claw and swan neck deformities. In ligament reconstruction, the A1 pulley has been used to reconstruct the transverse intermetacarpal ligament in cleft hand and ray amputations. The sheath has also been used to cover tendon repairs and periosteal defects with the aim of decreasing adhesions. There is potential for further use of the flexor sheath in reconstructive surgery. The digital flexor sheath can be used to restore various finger functions providing its physiological roles are recognized and preserved. This review considers the different techniques described and their potential uses.

  20. Hertwig’s Epithelial Root Sheath Fate during Initial Cellular Cementogenesis in Rat Molars

    International Nuclear Information System (INIS)

    Yamamoto, Tsuneyuki; Yamada, Tamaki; Yamamoto, Tomomaya; Hasegawa, Tomoka; Hongo, Hiromi; Oda, Kimimitsu; Amizuka, Norio

    2015-01-01

    To elucidate the fate of the epithelial root sheath during initial cellular cementogenesis, we examined developing maxillary first molars of rats by immunohistochemistry for keratin, vimentin, and tissue non-specific alkaline phosphatase (TNALP) and by TdT-mediated dUTP nick end labeling (TUNEL). The advancing root end was divided into three sections, which follow three distinct stages of initial cellular cementogenesis: section 1, where the epithelial sheath is intact; section 2, where the epithelial sheath becomes fragmented; and section 3, where initial cellular cementogenesis begins. After fragmentation of the epithelial sheath, many keratin-positive epithelial sheath cells were embedded in the rapidly growing cellular cementum. A few unembedded epithelial cells located on the cementum surface. Dental follicle cells, precementoblasts, and cementoblasts showed immunoreactivity for vimentin and TNALP. In all three sections, there were virtually no cells possessing double immunoreactivity for vimentin-keratin or TNALP-keratin and only embedded epithelial cells showed TUNEL reactivity. Taken together, these findings suggest that: (1) epithelial sheath cells divide into two groups; one group is embedded in the cementum and thereafter dies by apoptosis, and the other survives on the cementum surface as epithelial cell rests of Malassez; and (2) epithelial sheath cells do not undergo epithelial-mesenchymal transition during initial cellular cementogenesis

  1. Research on stress distribution regularity of cement sheaths of radial well based on ABAQUS

    Science.gov (United States)

    Shi, Jihui; Cheng, Yuanfang; Li, Xiaolong; Xiao, Wen; Li, Menglai

    2017-12-01

    To ensure desirable outcome of hydraulic fracturing based on ultra-short radius radial systems, it is required to investigate the stress distribution regularity and stability of the cement sheath. On the basis of the theoretical model of the cement sheath stress distribution, a reservoir mechanical model was built using the finite element software, ABAQUS, according to the physical property of a certain oil reservoir of the Shengli oilfield. The stress distribution of the casing-cement-sheath-formation system under the practical condition was simulated, based on which analyses were conducted from multiple points of view. Results show that the stress on the internal interface of the cement sheath exceeds that on the external interface, and fluctuates with higher amplitudes, which means that the internal interface is the most failure-prone. The unevenness of the cement sheath stress distribution grows with the increasing horizontal principal stress ratio, and so does the variation magnitude. This indicates that higher horizontal principal stress ratios are unfavourable for the structural stability of the cement sheath. Both the wellbore quantity of the URRS and the physical property of the material can affect the cement sheath distribution. It is suggested to optimize the quantity of the radial wellbore and use cement with a lower elastic modulus and higher Poisson’s ratio. At last, the impact level of the above factor was analysed, with the help of the grey correlation analysis.

  2. Fibrous zinc anodes for high power batteries

    Science.gov (United States)

    Zhang, X. Gregory

    This paper introduces newly developed solid zinc anodes using fibrous material for high power applications in alkaline and large size zinc-air battery systems. The improved performance of the anodes in these two battery systems is demonstrated. The possibilities for control of electrode porosity and for anode/battery design using fibrous materials are discussed in light of experimental data. Because of its mechanical integrity and connectivity, the fibrous solid anode has good electrical conductivity, mechanical stability, and design flexibility for controlling mass distribution, porosity and effective surface area. Experimental data indicated that alkaline cells made of such anodes can have a larger capacity at high discharging currents than commercially available cells. It showed even greater improvement over commercial cells with a non-conventional cell design. Large capacity anodes for a zinc-air battery have also been made and have shown excellent material utilization at various discharge rates. The zinc-air battery was used to power an electric bicycle and demonstrated good results.

  3. Accounting for Debye sheath expansion for proud Langmuir probes in magnetic confinement fusion plasmas

    Science.gov (United States)

    Tsui, C. K.; Boedo, J. A.; Stangeby, P. C.; TCV Team

    2018-01-01

    A Child-Langmuir law-based method for accounting for Debye sheath expansion while fitting the current-voltage I-V characteristic of proud Langmuir probes (electrodes that extend into the volume of the plasma) is described. For Langmuir probes of a typical size used in tokamak plasmas, these new estimates of electron temperature and ion saturation current density values decreased by up to 60% compared to methods that did not account for sheath expansion. Changes to the collection area are modeled using the Child-Langmuir law and effective expansion perimeter lp, and the model is thus referred to as the "perimeter sheath expansion method." lp is determined solely from electrode geometry, so the method may be employed without prior measurement of the magnitude of the sheath expansion effects for a given Langmuir probe and can be used for electrodes of different geometries. This method correctly predicts the non-saturating ΔI/ΔV slope for cold, low-density plasmas where sheath-expansion effects are strong, as well as for hot plasmas where ΔI/ΔV ˜ 0, though it is shown that the sheath can still significantly affect the collection area in these hot conditions. The perimeter sheath expansion method has several advantages compared to methods where the non-saturating current is fitted: (1) It is more resilient to scatter in the I-V characteristics observed in turbulent plasmas. (2) It is able to separate the contributions to the ΔI/ΔV slope from sheath expansion to that of the high energy electron tail in high Te conditions. (3) It calculates the change in the collection area due to the Debye sheath for conditions where ΔI/ΔV ˜ 0 and for V = Vf.

  4. Soil sheaths, photosynthate distribution to roots, and rhizosphere water relations for Opuntia ficus-indica

    Energy Technology Data Exchange (ETDEWEB)

    Huang, B.; North, G.B.; Nobel, P.S. (Univ. of California, Los Angeles, CA (United States))

    1993-09-01

    Soil sheaths incorporating aggregated soil particles surround young roots of many species, but the effects of such sheaths on water movement between roots and the soil are largely unknown. The quantity and location of root exudates associated with soil sheath along the entire length of its young roots, except within 1.4 cm of the tip. The soil sheaths, which average 0.7 mm in thickness, were composed of soil particles and root hairs, both of which were covered with exuded mucilaginous material. As determined with a [sup 14]C pulse-labeling technique, 2% of newly fixed [sup 14]C-photosynthate was translocated into the roots at 3d, 6% at 9 d, and 8% at 15 d after labeling. The fraction of insoluble [sup 14]C in the roots increased twofold from 3 d to 15 d. Over the same time period, 6%-9% of the [sup 14]C translocated to the roots was exuded into the soil. The soluble [sup 14]C compounds exuded into the soil were greater in the 3-cm segment at the root tip than elsewhere along the root, whereas mucilage was exuded relatively uniformly along roots 15 cm in length. The volumetric efflux of water increase for both sheathed and unsheathed roots as the soil water potential decreased form -0.1 MPa to -1.0 MPa. The efflux rate was greater for unsheathed roots than for sheathed roots, which were more turgid and had a higher water potential, especially at lower soil water potentials. During drying, soil particles in the sheaths aggregate more tightly, making the sheaths less permeable to water and possibly creating air gaps. The soil sheaths of O. ficus-indica thus reduce water loss from the roots to a drying soil. 34 refs., 6 figs., 1 tab.

  5. Accounting for Debye sheath expansion for proud Langmuir probes in magnetic confinement fusion plasmas.

    Science.gov (United States)

    Tsui, C K; Boedo, J A; Stangeby, P C

    2018-01-01

    A Child-Langmuir law-based method for accounting for Debye sheath expansion while fitting the current-voltage I-V characteristic of proud Langmuir probes (electrodes that extend into the volume of the plasma) is described. For Langmuir probes of a typical size used in tokamak plasmas, these new estimates of electron temperature and ion saturation current density values decreased by up to 60% compared to methods that did not account for sheath expansion. Changes to the collection area are modeled using the Child-Langmuir law and effective expansion perimeter l p , and the model is thus referred to as the "perimeter sheath expansion method." l p is determined solely from electrode geometry, so the method may be employed without prior measurement of the magnitude of the sheath expansion effects for a given Langmuir probe and can be used for electrodes of different geometries. This method correctly predicts the non-saturating ΔI/ΔV slope for cold, low-density plasmas where sheath-expansion effects are strong, as well as for hot plasmas where ΔI/ΔV ∼ 0, though it is shown that the sheath can still significantly affect the collection area in these hot conditions. The perimeter sheath expansion method has several advantages compared to methods where the non-saturating current is fitted: (1) It is more resilient to scatter in the I-V characteristics observed in turbulent plasmas. (2) It is able to separate the contributions to the ΔI/ΔV slope from sheath expansion to that of the high energy electron tail in high Te conditions. (3) It calculates the change in the collection area due to the Debye sheath for conditions where ΔI/ΔV ∼ 0 and for V = V f .

  6. Energy reversible switching from amorphous metal based nanoelectromechanical switch

    KAUST Repository

    Mayet, Abdulilah M.

    2013-08-01

    We report observation of energy reversible switching from amorphous metal based nanoelectromechanical (NEM) switch. For ultra-low power electronics, NEM switches can be used as a complementary switching element in many nanoelectronic system applications. Its inherent zero power consumption because of mechanical detachment is an attractive feature. However, its operating voltage needs to be in the realm of 1 volt or lower. Appropriate design and lower Young\\'s modulus can contribute achieving lower operating voltage. Therefore, we have developed amorphous metal with low Young\\'s modulus and in this paper reporting the energy reversible switching from a laterally actuated double electrode NEM switch. © 2013 IEEE.

  7. Normal tendon sheath of the second to fifth fingers as seen on oblique views

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, E.

    1984-01-01

    Oblique views of the fingers, using a low kilovolt technique, show a portion of the tendon sheaths which can be regarded as representative of the entire sheath. Because of the varying obliquity of each finger, this proportion differs in the fingers. With increasing age the projected portion of the sheath becomes smaller because it is covered by increasing bone formation in the insertion of the tendon sheat. Normal values have been obtained for adults according to their decades; from these, quite minor degrees of tendon sheat thickening can be determined. In camptodactyly of the fifth finger, which is not uncommon, the tendon sheat may be widened in the absence of a tenosynovitis.

  8. Switching power supply

    Science.gov (United States)

    Mihalka, A.M.

    1984-06-05

    The invention is a repratable capacitor charging, switching power supply. A ferrite transformer steps up a dc input. The transformer primary is in a full bridge configuration utilizing power MOSFETs as the bridge switches. The transformer secondary is fed into a high voltage, full wave rectifier whose output is connected directly to the energy storage capacitor. The transformer is designed to provide adequate leakage inductance to limit capacitor current. The MOSFETs are switched to the variable frequency from 20 to 50 kHz to charge a capacitor from 0.6 kV. The peak current in a transformer primary and secondary is controlled by increasing the pulse width as the capacitor charges. A digital ripple counter counts pulses and after a preselected desired number is reached an up-counter is clocked.

  9. Optical computer switching network

    Science.gov (United States)

    Clymer, B.; Collins, S. A., Jr.

    1985-01-01

    The design for an optical switching system for minicomputers that uses an optical spatial light modulator such as a Hughes liquid crystal light valve is presented. The switching system is designed to connect 80 minicomputers coupled to the switching system by optical fibers. The system has two major parts: the connection system that connects the data lines by which the computers communicate via a two-dimensional optical matrix array and the control system that controls which computers are connected. The basic system, the matrix-based connecting system, and some of the optical components to be used are described. Finally, the details of the control system are given and illustrated with a discussion of timing.

  10. Dissociation and Re-Aggregation of Multicell-Ensheathed Fragments Responsible for Rapid Production of Massive Clumps of Leptothrix Sheaths

    Science.gov (United States)

    Kunoh, Tatsuki; Nagaoka, Noriyuki; McFarlane, Ian R.; Tamura, Katsunori; El-Naggar, Mohamed Y.; Kunoh, Hitoshi; Takada, Jun

    2016-01-01

    Species of the Fe/Mn-oxidizing bacteria Leptothrix produce tremendous amounts of microtubular, Fe/Mn-encrusted sheaths within a few days in outwells of groundwater that can rapidly clog water systems. To understand this mode of rapid sheath production and define the timescales involved, behaviors of sheath-forming Leptothrix sp. strain OUMS1 were examined using time-lapse video at the initial stage of sheath formation. OUMS1 formed clumps of tangled sheaths. Electron microscopy confirmed the presence of a thin layer of bacterial exopolymer fibrils around catenulate cells (corresponding to the immature sheath). In time-lapse videos, numerous sheath filaments that extended from the periphery of sheath clumps repeatedly fragmented at the apex of the same fragment, the fragments then aggregated and again elongated, eventually forming a large sheath clump comprising tangled sheaths within two days. In this study, we found that fast microscopic fragmentation, dissociation, re-aggregation and re-elongation events are the basis of the rapid, massive production of Leptothrix sheaths typically observed at macroscopic scales. PMID:27490579

  11. Optical Packet Switching Demostrator

    DEFF Research Database (Denmark)

    Mortensen, Brian Bach; Berger, Michael Stübert

    2002-01-01

    In the IST project DAVID (data and voice integration over DWDM) work is carried out defining possible architectures of future optical packet switched networks. The feasibility of the architecture is to be verified in a demonstration set-up. This article describes the demonstrator set-up and the m......In the IST project DAVID (data and voice integration over DWDM) work is carried out defining possible architectures of future optical packet switched networks. The feasibility of the architecture is to be verified in a demonstration set-up. This article describes the demonstrator set...

  12. Plasma Switch Development.

    Science.gov (United States)

    1984-06-08

    ACCION NO. 3. RCIPIENT’S CATALOG NUMBER 4. TITLE (and Subtitle) 5. TYPE OF REPORT & PERIOD COVERED PLASMA SWITCH DEVELOPMENT Final Report: 02/26/82 thru...with an inductive energy store. At present, the are summarized state-of-he- art of high-power repetitive opening or doming switches is limited to...Alexandria, VA 22304. Figure 7 Is a circuit diagram of the proposed system. The desired load pulse parameters art -100- e References 1. R.D. Ford, 0. Jenkins

  13. Bearingless switched reluctance motor

    Science.gov (United States)

    Morrison, Carlos R. (Inventor)

    2004-01-01

    A switched reluctance motor has a stator with a first set of poles directed toward levitating a rotor horizontally within the stator. A disc shaped portion of a hybrid rotor is affected by the change in flux relative to the current provided at these levitation poles. A processor senses the position of the rotor and changes the flux to move the rotor toward center of the stator. A second set of poles of the stator are utilized to impart torque upon a second portion of the rotor. These second set of poles are driven in a traditional switched reluctance manner by the processor.

  14. 3D Parylene sheath neural probe for chronic recordings

    Science.gov (United States)

    Kim, B. J.; Kuo, J. T. W.; Hara, S. A.; Lee, C. D.; Yu, L.; Gutierrez, C. A.; Hoang, T. Q.; Pikov, V.; Meng, E.

    2013-08-01

    Objective. Reliable chronic recordings from implanted neural probes remain a significant challenge; current silicon-based and microwire technologies experience a wide range of biotic and abiotic failure modes contributing to loss of signal quality. Approach. A multi-prong alternative strategy with potential to overcome these hurdles is introduced that combines a novel three dimensional (3D), polymer-based probe structure with coatings. Specifically, the Parylene C sheath-based neural probe is coated with neurotrophic and anti-inflammatory factors loaded onto a Matrigel carrier to encourage the ingrowth of neuronal processes for improved recording quality, reduce the immune response, and promote improved probe integration into brain tissue for reliable, long-term implementation compared to its rigid counterparts. Main results. The 3D sheath structure of the probe was formed by thermal molding of a surface micromachined Parylene C microchannel, with electrode sites lining the interior and exterior regions of the lumen. Electrochemical characterization of the probes via cyclic voltammetry and electrochemical impedance spectroscopy was performed and indicated suitable electrode properties for neural recordings (1 kHz electrical impedance of ∼200 kΩ in vitro). A novel introducer tool for the insertion of the compliant polymer probe into neural tissue was developed and validated both in vitro using agarose gel and in vivo in the rat cerebral cortex. In vivo electrical functionality of the Parylene C-based 3D probes and their suitability for recording the neuronal activity over a 28-day period was demonstrated by maintaining the 1 kHz electrical impedance within a functional range (<400 kΩ) and achieving a reasonably high signal-to-noise ratio for detection of resolvable multi-unit neuronal activity on most recording sites in the probe. Immunohistochemical analysis of the implant site indicated strong correlations between the quality of recorded activity and the

  15. Pseudo-spark switch (PSS) characteristics under different operation conditions

    Energy Technology Data Exchange (ETDEWEB)

    Hamad, B. H., E-mail: dr.bassmahussain@gmail.com; Ahmad, A. K., E-mail: ahmad.kamal@sc.nahrainuniv.edu.iq [College of Science, Al Nahrain University, Jadria, Baghdad (Iraq); Lateef, K. H., E-mail: kamalhlatif@yahoo.com [Ministry of Science and Technology, Jadria, Baghdad (Iraq)

    2016-08-15

    The present paper concentrates on the characteristics of the pseudospark switch (PSS) designed in a previous work. The special characteristics of PSS make it a replacement for other high voltage switches such as thyratrons and ordinary high-pressure spark gaps. PSS is characterized by short rise time and small jitter time. The pseudo park chamber consists of two hollow cylindrical electrodes made of a stainless steel material (type 306L) separated by an insulator. The insulator used in our design is a glazed ceramic 70 mm in diameter and 3.5 mm in thickness. A PSS with an anode voltage of 29.2 kV, and a current of 3.6 kA and 11 ns rise time was achieved and used successfully at a repetition rate of about 2.2 kHz. A simple trigger circuit designed, built, and used effectively reaching more than 1.56 kV trigger pulse which is sufficient to ignite the argon gas inside the cathode to cause a breakdown. A non-inductive dummy load is designed to be a new technique to find the accurate value of the PSS inductance. A jitter time of ±10 ns pulses is observed to occur in a reliable manner for more than 6 h of continuous operation. In this research, the important parameters of this switch like rise time, peak current, and anode voltage were studied at various values of charging capacitance. The lifetime of this system is depending on the kind of the electrode material and on the type of insulation material in the main gap of the pseudospark switch.

  16. Design and fabrication of a silicon-based MEMS acceleration switch working lower than 10 g

    Science.gov (United States)

    Hwang, Jeongki; Ryu, Daeho; Park, Chihyun; Jang, Seung-gyo; Lee, Chung-il; Kim, Yong-Kweon

    2017-06-01

    This paper reports a low-g MEMS acceleration switch with threshold acceleration below 10 g. The proposed switch is made of single-crystalline silicon for high thermal stability and stress-free structure. A vertical operation type is adopted to enable fine control of the contact surface during the fabrication process. The switch contains displacement-restricting structures in all directions for impact resistance and is packaged with anodic bonding process. The fabricated switches had an average proof mass, initial gap, and spring constant of 307.38 µg, 6.39 µm, and 3.29 N m-1, respectively. Height profile of the free-hanging proof mass was measured to show that the switch does not suffer from stress problems. In the electrostatic operation test, the contact resistance of the switch was varied with contact force and the minimum value was estimated to be 8.5 Ω. The response time of the switch was measured to be shorter than 1.2 ms. The fabricated switch operated more than 10 000 cycles without failure. For the thermal stability test, the switch was heated at 80 °C for 6 h and the switch operated successfully over 200 times. In the rotation-table experiment, the switch operated at 6.61 g and error analysis was carried out in the consideration of tangential force generated during the rotation-table experiment. From the experimental values, the tangential force was calculated as 2.375 µN and the resulting reduction in the initial switching gap was simulated as 0.32 µm. The reduced threshold acceleration thus was estimated to be 6.62 g, which agrees very well with the measured threshold acceleration value of 6.61 g.

  17. New High-Energy Nanofiber Anode Materials

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiangwu [North Carolina State Univ., Raleigh, NC (United States); Fedkiw, Peter [North Carolina State Univ., Raleigh, NC (United States); Khan, Saad [North Carolina State Univ., Raleigh, NC (United States); Huang, Alex [North Carolina State Univ., Raleigh, NC (United States); Fan, Jiang [North Carolina State Univ., Raleigh, NC (United States)

    2013-11-15

    The overall goal of the proposed work was to use electrospinning technology to integrate dissimilar materials (lithium alloy and carbon) into novel composite nanofiber anodes, which simultaneously had high energy density, reduced cost, and improved abuse tolerance. The nanofiber structure allowed the anodes to withstand repeated cycles of expansion and contraction. These composite nanofibers were electrospun into nonwoven fabrics with thickness of 50 μm or more, and then directly used as anodes in a lithium-ion battery. This eliminated the presence of non-active materials (e.g., conducting carbon black and polymer binder) and resulted in high energy and power densities. The nonwoven anode structure also provided a large electrode-electrolyte interface and, hence, high rate capacity and good lowtemperature performance capability. Following are detailed objectives for three proposed project periods. During the first six months: Obtain anodes capable of initial specific capacities of 650 mAh/g and achieve ~50 full charge/discharge cycles in small laboratory scale cells (50 to 100 mAh) at the 1C rate with less than 20 percent capacity fade; In the middle of project period: Assemble, cycle, and evaluate 18650 cells using proposed anode materials, and demonstrate practical and useful cycle life (750 cycles of ~70% state of charge swing with less than 20% capacity fade) in 18650 cells with at least twice improvement in the specific capacity than that of conventional graphite electrodes; At the end of project period: Deliver 18650 cells containing proposed anode materials, and achieve specific capacities greater than 1200 mAh/g and cycle life longer than 5000 cycles of ~70% state of charge swing with less than 20% capacity fade.

  18. Performance of a plasma opening switch in positive polarity on Gamble I using flashboard plasma sources

    International Nuclear Information System (INIS)

    Renk, T.J.

    1995-01-01

    The successful development of the Plasma Opening Switch (POS) for inductive storage applications has been largely confined to negative polarity operation. Some models of POS behavior suggest that this is because in a positive polarity coaxial configuration, the weaker magnetic field at the cathode position retards the switch opening process. This article describes experiments in which both conductor radii in the POS region were significantly reduced. Anode- and cathode-side current monitors indicate that voltages greater than open-circuit are generated at the POS position, but there is a significant amount of electron flow out of the POS, depending upon load impedance. Flow impedance analysis indicates that a relatively small gap appears in the POS plasma after switch opening. Switch performance is also compared between flashboard and carbon gun plasma sources, with the latter operated both in positive and negative polarity

  19. Non-oxidized porous silicon-based power AC switch peripheries

    Science.gov (United States)

    Menard, Samuel; Fèvre, Angélique; Valente, Damien; Billoué, Jérôme; Gautier, Gaël

    2012-10-01

    We present in this paper a novel application of porous silicon (PS) for low-power alternating current (AC) switches such as triode alternating current devices (TRIACs) frequently used to control small appliances (fridge, vacuum cleaner, washing machine, coffee makers, etc.). More precisely, it seems possible to benefit from the PS electrical insulation properties to ensure the OFF state of the device. Based on the technological aspects of the most commonly used AC switch peripheries physically responsible of the TRIAC blocking performances (leakage current and breakdown voltage), we suggest to isolate upper and lower junctions through the addition of a PS layer anodically etched from existing AC switch diffusion profiles. Then, we comment the voltage capability of practical samples emanating from the proposed architecture. Thanks to the characterization results of simple Al-PS-Si(P) structures, the experimental observations are interpreted, thus opening new outlooks in the field of AC switch peripheries.

  20. Comparison of a fuel sheath failure model with published experimental data

    International Nuclear Information System (INIS)

    Varty, R.L.; Rosinger, H.E.

    1982-01-01

    A fuel sheath failure model has been compared with the published results of experiments in which a Zircaloy-4 fuel sheath was subjected to a temperature ramp and a differential pressure until failure occurred. The model assumes that the deformation of the sheath is controlled by steady-state creep and that there is a relationship between tangential stress and temperature at the instant of failure. The sheath failure model predictions agree reasonably well with the experimental data. The burst temperature is slightly overpredicted by the model. The burst strain is overpredicted for small experimental burst strains but is underpredicted otherwise. The reasons for these trends are discussed and the extremely wide variation in burst strain reported in the literature is explained using the model

  1. The endomembrane sheath: a key structure for understanding the plant cell?

    Science.gov (United States)

    Reuzeau, C.; McNally, J. G.; Pickard, B. G.

    1997-01-01

    Recent evidence suggests that integrin is abundant in endomembranes of plant cells, and the endomembranes are clad by a sheath of cytoskeleton including F-actin. A role for endomembrane integrin and the endomembrane sheath is proposed: this system might orchestrate metabolic regulation by providing and modulating loci for channelling, and might accelerate channeling as needed by dragging the endoplasmic reticulum (ER) and organelles through the cytoplasm. To accomplish this "streaming", F-actin might lever against the rest of the endomembrane sheath and the ER might also lever against adhesion sites (i.e., plasmodesmata and plasmalemmal control centers). As an important agent in the control of cellular activities, according to this model, the endomembrane sheath would play a major part in responses to diverse signals and stresses, and under extreme stress cell survival would depend on the ability of the system to maintain enough integrity to direct critical syntheses and degradations.

  2. Polyacrylonitrile nanofibers prepared using coaxial electrospinning with LiCl solution as sheath fluid

    International Nuclear Information System (INIS)

    Yu Dengguang; Yang Junhe; Wang Xia; Lu Ping; Branford-White, Christopher

    2011-01-01

    A modified coaxial electrospinning process including an electrolyte solution as sheath fluid was used for preparing high quality polymer nanofibers. A series of polyacrylonitrile (PAN) nanofibers were fabricated utilizing a coaxial electrospinning containing LiCl in N, N-dimethylacetamide (DMAc) as the sheath fluid. FESEM results demonstrated that the sheath LiCl solutions have a significant influence on the quality of PAN nanofibers. Nanofibers with smaller diameters, smoother surfaces and uniform structures were successfully prepared. The diameters of nanofibers were controlled by adjusting the conductivity of the sheath fluid over a suitable range and this was determined by varying LiCl concentrations. The influence of the effect of LiCl on the formation of PAN fibers is discussed and it is concluded that coaxial electrospinning with electrolyte solutions is a convenient and facile process for achieving high quality polymer nanofibers.

  3. The Tubular Sheaths Encasing Methanosaeta and Methanospirillum Filaments are Functional Amyloids

    DEFF Research Database (Denmark)

    Dueholm, Morten Simonsen; Larsen, Poul; Nielsen, Per Halkjær

    Archaea are well-recognized for their ability to thrive in extreme environments, although they can be found in virtually all habitats. Their adaptive success is linked to their unique cell envelopes, which often display extremely resistant to chemical and thermal denaturation and resist proteolysis...... techniques to show that the extracellular cell wall sheaths of the methanogenic archaea Methanosaeta and Methanospirillum are functional amyloid structures. Depolymerization of sheaths with formic acid and reducing agents and subsequent MS/MS analysis revealed that the sheaths are composed of a single major...... sheath protein (MspA). The amyloidogenic nature of MspA was confirmed by in vitro amyloid formation of recombinant MspA under a wide range of environmental conditions. This is the first report of a functional amyloid from the archaeal domain of life. The amyloid properties explain the extreme resistance...

  4. The effect of flexor sheath integrity on nutrient uptake by chicken flexor tendons.

    Science.gov (United States)

    Peterson, W W; Manske, P R; Lesker, P A

    1985-12-01

    The effect of varying degrees of flexor sheath integrity (sheath excised, incised, or incised and repaired) on the uptake of 3H-proline by chicken flexor tendons in Zone II was studied. The tendons were either: normal and uninjured, lacerated and repaired, or uninjured except for vinculum longum ligation. Different degrees of sheath integrity did not influence the uptake of 3H-proline by the tendons. The tendon does not appear to be dependent on a synovial environment for nutrients and is capable of obtaining these nutrients by diffusion from the surrounding extracellular tissue fluid. Diffusion is the primary nutrient pathway to the flexor tendon in this area, because removing its major vascular attachment (i.e., the vinculum longum) did not effect proline uptake. Careful closure of the sheath with restoration of a synovial environment does not appear to be necessary for tendon nutrition.

  5. Effect of flexor sheath integrity on nutrient uptake by chicken flexor tendons

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, W.W.; Manske, P.R.; Lesker, P.A.

    1985-12-01

    The effect of varying degrees of flexor sheath integrity (sheath excised, incised, or incised and repaired) on the uptake of /sub 2/H-proline by chicken flexor tendons in Zone II was studied. The tendons were either: normal and uninjured, lacerated and repaired, or uninjured except for vinculum longum ligation. Different degrees of sheath integrity did not influence the uptake of /sub 2/H-proline by the tendons. The tendon does not appear to be dependent on a synovial environment for nutrients and is capable of obtaining these nutrients by diffusion from the surrounding extracellular tissue fluid. Diffusion is the primary nutrient pathway to the flexor tendon in this area, because removing its major vascular attachment (i.e., the vinculum longum) did not effect proline uptake. Careful closure of the sheath with restoration of a synovial environment does not appear to be necessary for tendon nutrition.

  6. Teaching the transrectus sheath preperiotneal mesh repair: TREPP in 9 steps

    NARCIS (Netherlands)

    Akkersdijk, W.L.; Andeweg, C.S.; Bokkerink, W.J.V.; Lange, J.F.; Laarhoven, C.J.H.M. van; Koning, G.G.

    2016-01-01

    BACKGROUND: The preperitoneal mesh position seems preferable to reduce the number of patients with postoperative chronic pain after inguinal hernia surgery. The transrectus sheath preperitoneal mesh repair (TREPP) is gaining popularity. Teaching a new technique requires a standardized approach to

  7. Child-Langmuir law for cathode sheath of glow discharge in CO2

    International Nuclear Information System (INIS)

    Lisovskiy, V.A.; Krol, H.H.; Osmayev, R.O.; Yegorenkov, V.D.

    2016-01-01

    This work is devoted to the determination of the law that may be applicable to the description of the cathode sheath in CO 2 . To this end three versions of the Child-Langmuir law have been considered - a collision free one (for the ions moving through a cathode sheath without collisions with gas molecules) as well as two collision- related versions - one for a constant mean free path of positive ions and one for a constant mobility of positive ions. The current-voltage characteristics and the cathode sheath thickness of the glow discharge in CO 2 have been simultaneously measured in the pressure range from 0.05 to 1 Torr and with the discharge current values up to 80 mA. In the whole range of the discharge conditions we have studied the cathode sheath characteristics are found to obey correctly only to the Child-Langmuir law version with a constant ion mobility.

  8. Influence of plasma density and plasma sheath dynamics on the ion implantation by plasma immersion technique

    OpenAIRE

    Ensinger, Wolfgang

    1996-01-01

    Influence of plasma density and plasma sheath dynamics on the ion implantation by plasma immersion technique / B. Rauschenbach ... - In: Nuclear instruments and methods in physics research. B. 113. 1996. S. 266-269

  9. Effects of Reentry Plasma Sheath on GPS Patch Antenna Polarization Property

    Directory of Open Access Journals (Sweden)

    L. Zhao

    2013-01-01

    Full Text Available A plasma sheath enveloping a reentry vehicle would affect performances of on-board antenna greatly, especially the navigation antennas. This paper studies the effects of reentry plasma sheath on a GPS right-hand circularly polarized (RHCP patch antenna polarization property during a typical reentry process. Utilizing the algorithm of finite integration technique, the polarization characteristic of a GPS antenna coated by a plasma sheath is obtained. Results show that the GPS RHCP patch antenna radiation pattern distortions as well as polarization deteriorations exist during the entire reentry process, and the worst polarization mismatch loss between a GPS antenna and RHCP GPS signal is nearly 3 dB. This paper also indicates that measures should be taken to alleviate the plasma sheath for maintaining the GPS communication during the reentry process.

  10. OXIDATION OF DRY HYDROCARBONS AT HIGH-POWER DENSITY ANODES

    Energy Technology Data Exchange (ETDEWEB)

    K.Krist; O. Spaldon-Stewart; R. Remick

    2004-03-01

    This work builds upon discoveries by the University of Pennsylvania and others pertaining to the oxidation of dry hydrocarbon fuels in high temperature solid oxide fuel cells. The work reported here was restricted primarily to dry methane and confirms that YSZ-based cells, having ceria in the anode as a catalyst and copper in the anode as a current collector, can operate on dry methane for extended periods. Thirty-three lab-scale cells of various designs were fabricated and operated under a variety of conditions. The longest-lived cell gave stable performance on dry methane at 800 C for over 305 hours. Only slight carbon deposition was noted at the completion of the test. A corresponding nickel/YSZ-based anode would have lasted for less than an hour under these test conditions (which included open circuit potential measurements) before carbon fouling essentially destroyed the cell. The best performing cell achieved 112 mW/cm{sub 2} on dry methane at 800 C. Several problems were encountered with carbon fouling and declining open circuit voltages in many of the test cells after switching from operation on hydrogen to dry methane. Although not rigorously confirmed by experimentation, the results suggested that air infiltration through less than perfect perimeter seals or pinholes in the electrolytes, or both gave rise to conditions that caused the carbon fouling and OCV decline. Small amounts of air reacting with methane in a partial oxidation reaction could produce carbon monoxide that, in turn, would deposit the carbon. If this mechanism is confirmed, it implies that near perfect hardware is required for extended operation. Some evidence was also found for the formation of electrical shorts, probably from carbon deposits bridging the electrolyte. Work with odorized methane and with methane containing 100-ppm hydrogen sulfide confirmed that copper is stable at 800 C in dry hydrocarbon fuels in the presence of sulfur. In a number of cases, but not exclusively, the

  11. Ultrafast gas switching experiments

    International Nuclear Information System (INIS)

    Frost, C.A.; Martin, T.H.; Patterson, P.E.; Rinehart, L.F.; Rohwein, G.J.; Roose, L.D.; Aurand, J.F.; Buttram, M.T.

    1993-01-01

    We describe recent experiments which studied the physics of ultrafast gas breakdown under the extreme overvoltages which occur when a high pressure gas switch is pulse charged to hundreds of kV in 1 ns or less. The highly overvolted peaking gaps produce powerful electromagnetic pulses with risetimes Khz at > 100 kV/m E field

  12. Photonic MEMS switch applications

    Science.gov (United States)

    Husain, Anis

    2001-07-01

    As carriers and service providers continue their quest for profitable network solutions, they have shifted their focus from raw bandwidth to rapid provisioning, delivery and management of revenue generating services. Inherently transparent to data rate the transmission wavelength and data format, MEMS add scalability, reliability, low power and compact size providing flexible solutions to the management and/or fiber channels in long haul, metro, and access networks. MEMS based photonic switches have gone from the lab to commercial availability and are now currently in carrier trials and volume production. 2D MEMS switches offer low up-front deployment costs while remaining scalable to large arrays. They allow for transparent, native protocol transmission. 2D switches enable rapid service turn-up and management for many existing and emerging revenue rich services such as storage connectivity, optical Ethernet, wavelength leasing and optical VPN. As the network services evolve, the larger 3D MEMS switches, which provide greater scalability and flexibility, will become economically viable to serve the ever-increasing needs.

  13. Search and switching costs

    NARCIS (Netherlands)

    Siekman, Wilhelm Henricus

    2016-01-01

    This thesis analyses markets with search and with switching costs. It provides insights in several important issues in search markets, including how loss aversion may affect consumer behavior and firm conduct, and how prices, welfare, and profits may change when an intermediating platform orders

  14. The Octopus switch

    NARCIS (Netherlands)

    Havinga, Paul J.M.

    2000-01-01

    This chapter1 discusses the interconnection architecture of the Mobile Digital Companion. The approach to build a low-power handheld multimedia computer presented here is to have autonomous, reconfigurable modules such as network, video and audio devices, interconnected by a switch rather than by a

  15. Stochastic Switching Dynamics

    DEFF Research Database (Denmark)

    Simonsen, Maria

    mode control. It is investigated how to understand and interpret solutions to models of switched systems, which are exposed to discontinuous dynamics and uncertainties (primarily) in the form of white noise. The goal is to gain knowledge about the performance of the system by interpreting the solution...

  16. Surface damage by sheath effects and unipolar arcs

    International Nuclear Information System (INIS)

    Schwirzke, F.; Taylor, R.J.

    1980-01-01

    Unipolar arcing develops if the sheath potential is high enough. A laser-produced plasma of short duration was used to study the onset and development of arcing on a stainless stell surface. The laser-produced plasma with kTsub(e) approx. equal to 100 eV expands rapidly from the focal spot on the target surface in the normal and in radial directions. After one laser shot the damage on the polished surface was observed with an optical and a scanning electron microscope. Although no external voltage was applied, about 20 000 unipolar arc craters are observable on the stainless steel surface which was exposed to the radially expanding plasma for the short time of a few hundred nanoseconds. The size of the arc craters decreases with increasing distance from the focal spot. The initial cathode spot is 1 μm in diameter and 3-6 μm deep, acting like a hollow cathode. The arcs obviously contribute to the erosion of wall material. The experimental results also show that some of the eroded material is redeposited on stainless steel surfaces in loosely bound form. (orig.)

  17. Plasticity in bundle sheath extensions of heterobaric leaves.

    Science.gov (United States)

    Lynch, Douglas J; McInerney, Francesca A; Kouwenberg, Lenny L R; Gonzalez-Meler, Miquel A

    2012-07-01

    Leaf venation is linked to physiological performance, playing a critical role in ecosystem function. Despite the importance of leaf venation, associated bundle sheath extensions (BSEs) remain largely unstudied. Here, we quantify plasticity in the spacing of BSEs over irradiance and precipitation gradients. Because physiological function(s) of BSEs remain uncertain, we additionally explored a link between BSEs and water use efficiency (WUE). We sampled leaves of heterobaric trees along intracrown irradiance gradients in natural environments and growth chambers and correlated BSE spacing to incident irradiance. Additionally, we sampled leaves along a precipitation gradient and correlated BSE spacing to precipitation and bulk δ(13)C, a proxy for intrinsic WUE. BSE spacing was quantified using a novel semiautomatic method on fresh leaf tissue. With increased irradiance or decreased precipitation, Liquidambar styraciflua decreased BSE spacing, while Acer saccharum showed little variation in BSE spacing. Two additional species, Quercus robur and Platanus occidentalis, decreased BSE spacing with increased irradiance in growth chambers. BSE spacing correlated with bulk δ(13)C, a proxy for WUE in L. styraciflua, Q. robur, and P. occidentalis leaves but not in leaves of A. saccharum. We demonstrated that BSE spacing is plastic with respect to irradiance or precipitation and independent from veins, indicating BSE involvement in leaf adaptation to a microenvironment. Plasticity in BSE spacing was correlated with WUE only in some species, not supporting a function in water relations. We discuss a possible link between BSE plasticity and life history, particularly canopy position.

  18. Ral Overactivation in Malignant Peripheral Nerve Sheath Tumors▿

    Science.gov (United States)

    Bodempudi, Vidya; Yamoutpoor, Farnaz; Pan, Weihong; Dudek, Arkadiusz Z.; Esfandyari, Tuba; Piedra, Mark; Babovick-Vuksanovic, Dusica; Woo, Richard A.; Mautner, Victor F.; Kluwe, Lan; Clapp, D. Wade; De Vries, George H.; Thomas, Stacey L.; Kurtz, Andreas; Parada, Luis F.; Farassati, Faris

    2009-01-01

    Ras leads an important signaling pathway that is deregulated in neurofibromatosis type 1 and malignant peripheral nerve sheath tumor (MPNST). In this study, we show that overactivation of Ras and many of its downstream effectors occurred in only a fraction of MPNST cell lines. RalA, however, was overactivated in all MPNST cells and tumor samples compared to nontransformed Schwann cells. Silencing Ral or inhibiting it with a dominant-negative Ral (Ral S28N) caused a significant reduction in proliferation, invasiveness, and in vivo tumorigenicity of MPNST cells. Silencing Ral also reduced the expression of epithelial mesenchymal transition markers. Expression of the NF1-GTPase-related domain (NF1-GRD) diminished the levels of Ral activation, implicating a role for neurofibromin in regulating RalA activation. NF1-GRD treatment caused a significant decrease in proliferation, invasiveness, and cell cycle progression, but cell death increased. We propose Ral overactivation as a novel cell signaling abnormality in MPNST that leads to important biological outcomes with translational ramifications. PMID:19414599

  19. Ral overactivation in malignant peripheral nerve sheath tumors.

    Science.gov (United States)

    Bodempudi, Vidya; Yamoutpoor, Farnaz; Pan, Weihong; Dudek, Arkadiusz Z; Esfandyari, Tuba; Piedra, Mark; Babovick-Vuksanovic, Dusica; Woo, Richard A; Mautner, Victor F; Kluwe, Lan; Clapp, D Wade; De Vries, George H; Thomas, Stacey L; Kurtz, Andreas; Parada, Luis F; Farassati, Faris

    2009-07-01

    Ras leads an important signaling pathway that is deregulated in neurofibromatosis type 1 and malignant peripheral nerve sheath tumor (MPNST). In this study, we show that overactivation of Ras and many of its downstream effectors occurred in only a fraction of MPNST cell lines. RalA, however, was overactivated in all MPNST cells and tumor samples compared to nontransformed Schwann cells. Silencing Ral or inhibiting it with a dominant-negative Ral (Ral S28N) caused a significant reduction in proliferation, invasiveness, and in vivo tumorigenicity of MPNST cells. Silencing Ral also reduced the expression of epithelial mesenchymal transition markers. Expression of the NF1-GTPase-related domain (NF1-GRD) diminished the levels of Ral activation, implicating a role for neurofibromin in regulating RalA activation. NF1-GRD treatment caused a significant decrease in proliferation, invasiveness, and cell cycle progression, but cell death increased. We propose Ral overactivation as a novel cell signaling abnormality in MPNST that leads to important biological outcomes with translational ramifications.

  20. Malignant peripheral nerve sheath tumours in inherited disease

    Directory of Open Access Journals (Sweden)

    Evans D

    2012-10-01

    Full Text Available Abstract Background Malignant peripheral nerve sheath tumours (MPNST are rare tumours known to occur at high frequency in neurofibromatosis 1 (NF1, but may also occur in other cancer prone syndromes. Methods The North West Regional Genetic Register covers a population of 4.1 million and was interrogated for incidence of MPNST in 12 cancer prone syndromes. Age, incidence and survival curves were generated for NF1. Results Fifty two of 1254 NF1 patients developed MPNST, with MPNST also occurring in 2/181 cases of schwannomatosis and 2/895 NF2 patients. Three cases were also noted in TP53 mutation carriers. However, there were no cases amongst 5727BRCA1/2 carriers and first degree relatives, 2029 members from Lynch syndrome families, nor amongst 447 Familial Adenomatous Polyposis, 202 Gorlin syndrome, nor 87 vHL cases. Conclusion MPNST is associated with schwannomatosis and TP53 mutations and is confirmed at high frequency in NF1. It appears to be only increased in NF2 amongst those that have been irradiated. The lifetime risk of MPNST in NF1 is between 9–13%.

  1. MRI of intraspinal nerve sheath tumours presenting with sciatica

    Energy Technology Data Exchange (ETDEWEB)

    Loke, T.K.L.; Chan, C.S. [United Christian Hospital (Hong Kong). Dept. of Diagnostic Radiology; Ma, H.T.G. [St Teresa`s Hospital, Kowloon (Hong Kong). MRI and CT scanning Dept.; Ward, S.C.; Metreweli, C. [Prince of wales Hospital, New Territories (Hong Kong). Dept. of Diagnostic Radiology

    1995-08-01

    The magnetic resonance imaging (MRI) characteristics of 14 intraspinal nerve sheath tumours (NST) presenting with sciatica were reviewed. The group comprised seven schwannomas, six neurofibromas and one perineuroma. The tumours were either iso- or hypointense with respect to spinal cord on T1-weighted (T1W) images; almost all tumours were hyperintense compared with spinal cord on T2-weighted (T2W) images. The tumours were all detectable on unenhanced T1 W images. Nine NST were scanned following Gadolinium-Diethylenetriamine penta acetic acid (DTPA) injection and all showed intense enhancement. This aids differentiation from sequestrated disc fragments. Tumours were more likely to show homogeneous enhancement unless they were recurrent tumours. Rim enhancement occurs more commonly in schwannomas and this can be used to differentiate these from neurofibromas. It is estimated that on unenhanced images, schwannomas cannot be distinguished from neurofibromas. Four tumours occurred at T1 1-T12. There was poor correlation of the site of the lesion with the clinical findings. It is recommended that the MRI studies in patients with sciatica should include the lower thoracic region especially if no protruded disc was found in the lumbar region. 15 refs., 4 figs.

  2. Molecular Rotors as Switches

    Directory of Open Access Journals (Sweden)

    Kang L. Wang

    2012-08-01

    Full Text Available The use of a functional molecular unit acting as a state variable provides an attractive alternative for the next generations of nanoscale electronics. It may help overcome the limits of conventional MOSFETd due to their potential scalability, low-cost, low variability, and highly integratable characteristics as well as the capability to exploit bottom-up self-assembly processes. This bottom-up construction and the operation of nanoscale machines/devices, in which the molecular motion can be controlled to perform functions, have been studied for their functionalities. Being triggered by external stimuli such as light, electricity or chemical reagents, these devices have shown various functions including those of diodes, rectifiers, memories, resonant tunnel junctions and single settable molecular switches that can be electronically configured for logic gates. Molecule-specific electronic switching has also been reported for several of these device structures, including nanopores containing oligo(phenylene ethynylene monolayers, and planar junctions incorporating rotaxane and catenane monolayers for the construction and operation of complex molecular machines. A specific electrically driven surface mounted molecular rotor is described in detail in this review. The rotor is comprised of a monolayer of redox-active ligated copper compounds sandwiched between a gold electrode and a highly-doped P+ Si. This electrically driven sandwich-type monolayer molecular rotor device showed an on/off ratio of approximately 104, a read window of about 2.5 V, and a retention time of greater than 104 s. The rotation speed of this type of molecular rotor has been reported to be in the picosecond timescale, which provides a potential of high switching speed applications. Current-voltage spectroscopy (I-V revealed a temperature-dependent negative differential resistance (NDR associated with the device. The analysis of the device

  3. ICME-driven sheath regions deplete the outer radiation belt electrons

    Science.gov (United States)

    Hietala, H.; Kilpua, E. K.; Turner, D. L.

    2013-12-01

    It is an outstanding question in space weather and solar wind-magnetosphere interaction studies, why some storms result in an increase of the outer radiation belt electron fluxes, while others deplete them or produce no change. One approach to this problem is to look at differences in the storm drivers. Traditionally drivers have been classified to Stream Interaction Regions (SIRs) and Interplanetary Coronal Mass Ejections (ICMEs). However, an 'ICME event' is a complex structure: The core is a magnetic cloud (MC; a clear flux rope structure). If the mass ejection is fast enough, it can drive a shock in front of it. This leads to the formation of a sheath region between the interplanetary shock and the leading edge of the MC. While both the sheath and the MC feature elevated solar wind speed, their other properties are very different. For instance, the sheath region has typically a much higher dynamic pressure than the magnetic cloud. Moreover, the sheath region has a high power in magnetic field and dynamic pressure Ultra Low Frequency (ULF) range fluctuations, while the MC is characterised by an extremely smooth magnetic field. Magnetic clouds have been recognised as important drivers magnetospheric activity since they can comprise long periods of very large southward Interplanetary Magnetic Field (IMF). Nevertheless, previous studies have shown that sheath regions can also act as storm drivers. In this study, we analyse the effects of ICME-driven sheath regions on the relativistic electron fluxes observed by GOES satellites on the geostationary orbit. We perform a superposed epoch analysis of 31 sheath regions from solar cycle 23. Our results show that the sheaths cause an approximately one order of magnitude decrease in the 24h-averaged electron fluxes. Typically the fluxes also stay below the pre-event level for more than two days. Further analysis reveals that the decrease does not depend on, e.g., whether the sheath interval contains predominantly northward

  4. Electrolytic Cell For Production Of Aluminum Employing Planar Anodes.

    Energy Technology Data Exchange (ETDEWEB)

    Barnett, Robert J. (Goldendale, WA); Mezner, Michael B. (Sandy, OR); Bradford, Donald R (Underwood, WA)

    2004-10-05

    A method of producing aluminum in an electrolytic cell containing alumina dissolved in an electrolyte, the method comprising providing a molten salt electrolyte having alumina dissolved therein in an electrolytic cell. A plurality of anodes and cathodes having planar surfaces are disposed in a generally vertical orientation in the electrolyte, the anodes and cathodes arranged in alternating or interleaving relationship to provide anode planar surfaces disposed opposite cathode planar surfaces, the anode comprised of carbon. Electric current is passed through anodes and through the electrolyte to the cathodes depositing aluminum at the cathodes and forming carbon containing gas at the anodes.

  5. Optic Nerve Sheath Diameter Increase on Ascent to High Altitude: Correlation With Acute Mountain Sickness.

    Science.gov (United States)

    Kanaan, Nicholas C; Lipman, Grant S; Constance, Benjamin B; Holck, Peter S; Preuss, James F; Williams, Sarah R

    2015-09-01

    Elevated optic nerve sheath diameter on sonography is known to correlate with increased intracranial pressure and is observed in acute mountain sickness. This study aimed to determine whether optic nerve sheath diameter changes on ascent to high altitude are associated with acute mountain sickness incidence. Eighty-six healthy adults enrolled at 1240 m (4100 ft), drove to 3545 m (11,700 ft) and then hiked to and slept at 3810 m (12,500 ft). Lake Louise Questionnaire scores and optic nerve sheath diameter measurements were taken before, the evening of, and the morning after ascent. The incidence of acute mountain sickness was 55.8%, with a mean Lake Louise Questionnaire score ± SD of 3.81 ± 2.5. The mean maximum optic nerve sheath diameter increased on ascent from 5.58 ± 0.79 to 6.13 ± 0.73 mm, a difference of 0.91 ± 0.55 mm (P = .09). Optic nerve sheath diameter increased at high altitude regardless of acute mountain sickness diagnosis; however, compared to baseline values, we observed a significant increase in diameter only in those with a diagnosis of acute mountain sickness (0.57 ± 0.77 versus 0.21 ± 0.76 mm; P = .04). This change from baseline, or Δ optic nerve sheath diameter, was associated with twice the odds of developing acute mountain sickness (95% confidence interval, 1.08-3.93). The mean optic nerve sheath diameter increased on ascent to high altitude compared to baseline values, but not to a statistically significant degree. The magnitude of the observed Δ optic nerve sheath diameter was positively associated with acute mountain sickness diagnosis. No such significant association was found between acute mountain sickness and diameter elevation above standard cutoff values, limiting the utility of sonography as a diagnostic tool. © 2015 by the American Institute of Ultrasound in Medicine.

  6. Ganglion of the Flexor Tendon Sheath at the A2 Pulley - Case Report

    Directory of Open Access Journals (Sweden)

    P Gunaseelan

    2015-03-01

    Full Text Available There are few reported cases of flexor tendon sheath ganglion arising from the A2 pulley. We report a case of a flexor tendon sheath ganglion in a 17-year old female who presented with pain, triggering and a swelling at the base of her right ring finger. During the excision biopsy, a ganglion measuring 0.5×0.8×0.4 cm in size was removed from the A2 pulley area.

  7. Novel Therapeutic Development of NF1-Associated Malignant Peripheral Nerve Sheath Tumor (MPNST)

    Science.gov (United States)

    2016-08-01

    Biological Analyses of Malignant Peripheral Nerve Sheath Tumors (MPNST)” 2) Journal article : Prieto-Granada CN, Wiesner T, Messina JL, Jungbluth...benign peripheral nerve sheath tumor , and/or focal S100 protein positivity (ង%) in the absence of other markers . The epithelioid MPNST cases displayed...diffusely S100 protein positive, and 2 of the tumors tested with INI1/SMARCB1 (MPNST54, 58) also showed loss of expression of this marker . Prieto

  8. Fibrin Sheath Angioplasty: A Technique to Prevent Superior Vena Cava Stenosis Secondary to Dialysis Catheters

    Science.gov (United States)

    Hacker, Robert I.; Garcia, Lorena De Marco; Chawla, Ankur; Panetta, Thomas F.

    2012-01-01

    Fibrin sheaths are a heterogeneous matrix of cells and debris that form around catheters and are a known cause of central venous stenosis and catheter failure. A total of 50 cases of central venous catheter fibrin sheath angioplasty (FSA) after catheter removal or exchange are presented. A retrospective review of an outpatient office database identified 70 eligible patients over a 19-month period. After informed consent was obtained, the dialysis catheter exiting the skin was clamped, amputated, and a wire was inserted. The catheter was then removed and a 9-French sheath was inserted into the superior vena cava, a venogram was performed. If a fibrin sheath was present, angioplasty was performed using an 8 × 4 or 10 × 4 balloon along the entire length of the fibrin sheath. A completion venogram was performed to document obliteration of the sheath. During the study, 50 patients were diagnosed with a fibrin sheath, and 43 had no pre-existing central venous stenosis. After FSA, 39 of the 43 patient's (91%) central systems remained patent without the need for subsequent interventions; 3 patients (7%) developed subclavian stenoses requiring repeat angioplasty and stenting; 1 patent (2.3%) developed an occlusion requiring a reintervention. Seven patients with prior central stenosis required multiple angioplasties; five required stenting of their central lesions. Every patient had follow-up fistulograms to document long-term patency. We propose that FSA is a prudent and safe procedure that may help reduce the risk of central venous stenosis from fibrin sheaths due to central venous catheters. PMID:23997555

  9. Tunneled dialysis catheter exchange with fibrin sheath disruption is not associated with increased rate of bacteremia.

    Science.gov (United States)

    Valliant, Amanda M; Chaudhry, Muhammad K; Yevzlin, Alexander S; Astor, Brad; Chan, Micah R

    2015-01-01

    Tunneled dialysis catheters are the most common form of vascular access among incident dialysis patients in the United States. Fibrin sheath formation is a frequent cause of late catheter dysfunction requiring an exchange procedure with balloon disruption of the fibrin sheath. It is unknown whether fibrin sheath disruption is associated with increased incidence of bacteremia or catheter failure. We reviewed all tunneled dialysis catheter exchange procedures at the University of Wisconsin between January 2008 and December 2011. The primary outcome was incidence of bacteremia, defined as positive blood cultures within 2 weeks of the procedure. Catheter failure, requiring intervention or replacement, was examined as a secondary outcome. Baseline characteristics examined included diabetic status, gender, race and age. A total of 163 procedures were reviewed; 67 (41.1%) had fibrin sheath disruption and 96 did not. Bacteremia occurred in 4.5% (3/67) of those with and 3.1% (3/97) of those without fibrin sheath disruption (p=0.65). Fibrin sheath disruption was not significantly associated with the risk of catheter failure (adjusted hazard ratio [aHR]=1.34; 95% confidence interval [CI]: 0.87-2.10; p=0.18). Diabetes was associated with greater risk of catheter failure (aHR=1.88; 95% CI: 1.19-2.95; p=0.006), whereas higher age was associated with a lower risk of catheter failure (aHR per 10 years=0.83; 95% CI: 0.72-0.96; p=0.01). This study demonstrates that there is no significant increase in bacteremia and subsequent catheter dysfunction rates after fibrin sheath disruption compared to simple over the wire exchange. These results are encouraging given the large numbers of patients utilizing tunneled catheters for initial hemodialysis access and the known rates of fibrin sheath formation leading to catheter failure.

  10. Control synthesis of switched systems

    CERN Document Server

    Zhao, Xudong; Niu, Ben; Wu, Tingting

    2017-01-01

    This book offers its readers a detailed overview of the synthesis of switched systems, with a focus on switching stabilization and intelligent control. The problems investigated are not only previously unsolved theoretically but also of practical importance in many applications: voltage conversion, naval piloting and navigation and robotics, for example. The book considers general switched-system models and provides more efficient design methods to bring together theory and application more closely than was possible using classical methods. It also discusses several different classes of switched systems. For general switched linear systems and switched nonlinear systems comprising unstable subsystems, it introduces novel ideas such as invariant subspace theory and the time-scheduled Lyapunov function method of designing switching signals to stabilize the underlying systems. For some typical switched nonlinear systems affected by various complex dynamics, the book proposes novel design approaches based on inte...

  11. Bucket and straw technique to facilitate passage of a ventriculoperitoneal shunt through the distal tunneling sheath.

    Science.gov (United States)

    Downes, Angela E; Vandergrift, William A; Beckman, Joshua M; Truong, Devon; Tuite, Gerald F

    2014-12-01

    Placement of a ventriculoperitoneal shunt (VPS) is a procedure comprising many small steps. Difficulties and delays can arise when passing the distal shunt tubing down the distal tunneling sheath during surgery. The authors of this report describe a simple technique for quickly passing the distal catheter of a VPS through the tunneler sheath, whereby the sheath is used as a fluid tube to allow the distal catheter to be drawn through the fluid tube under suction pressure. The plastic sheath that surrounds the shunt tunneler device is used as a fluid tube, or "straw," with the proximal aperture submerged into a bucket of sterile irrigation liquid containing the distal catheter. Suction pressure is placed against the distal aperture of the tunneler, and the shunt catheter is quickly drawn through the sheath. No special equipment is required. In time trials, the bucket and straw technique took an average of 0.43 seconds, whereas traditional passage methods took 32.3 seconds. The "bucket and straw" method for passing distal shunt tubing through the tunneler sheath is a technique that increases surgical efficiency and reduces manual contact with shunt hardware.

  12. Magnetically modified sheaths of Leptothrix sp. as an adsorbent for Amido black 10B removal

    Energy Technology Data Exchange (ETDEWEB)

    Angelova, Ralitsa [Department of Nanobiotechnology, Biology Centre, ISB, CAS, Na Sadkach 7, 370 05 Ceske Budejovice (Czech Republic); Department of General and Industrial Microbiology, Faculty of Biology, Sofia University “St. Kliment Ohridski”, 8 Dragan Tsankov Blvd, 1164 Sofia (Bulgaria); Laboratory Microwave Magnetics, Institute of Electronics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee Blvd, 1784 Sofia (Bulgaria); Baldikova, Eva [Global Change Research Institute, CAS, Na Sadkach 7, 370 05 Ceske Budejovice (Czech Republic); Department of Applied Chemistry, Faculty of Agriculture, University of South Bohemia, Branisovska 1457, 370 05 Ceske Budejovice (Czech Republic); Pospiskova, Kristyna [Regional Centre of Advanced Technologies and Materials, Palacky University, Slechtitelu 27, 783 71 Olomouc (Czech Republic); Safarikova, Mirka [Department of Nanobiotechnology, Biology Centre, ISB, CAS, Na Sadkach 7, 370 05 Ceske Budejovice (Czech Republic); Global Change Research Institute, CAS, Na Sadkach 7, 370 05 Ceske Budejovice (Czech Republic); Safarik, Ivo, E-mail: ivosaf@yahoo.com [Department of Nanobiotechnology, Biology Centre, ISB, CAS, Na Sadkach 7, 370 05 Ceske Budejovice (Czech Republic); Global Change Research Institute, CAS, Na Sadkach 7, 370 05 Ceske Budejovice (Czech Republic); Regional Centre of Advanced Technologies and Materials, Palacky University, Slechtitelu 27, 783 71 Olomouc (Czech Republic)

    2017-04-01

    The goal of this study was to assess the biosorption of Amido black 10B dye from aqueous solutions on magnetically modified sheaths of Leptothrix sp. in a batch system. The magnetic modification of the sheaths was performed using both microwave synthesized iron oxide nano- and microparticles and perchloric acid stabilized ferrofluid. The native and both magnetically modified sheaths were characterized by SEM. Various parameters significantly affecting the adsorption process, such as pH, contact time, temperature and initial concentration, were studied in detail using the adsorbent magnetized by both methods. The highest adsorption efficiency was achieved at pH 2. The maximum adsorption capacities of both types of magnetized material at room temperature were found to be 339.2 and 286.1 mg of dye per 1 g of ferrofluid modified and microwave synthesized particles modified adsorbent, respectively. Thermodynamic study of dye adsorption revealed a spontaneous and endothermic process in the temperature range between 279.15 and 313.15 K. The data were fitted to various equilibrium and kinetic models. Experimental data matched well with the pseudo-second-order kinetics and Freundlich isotherm model. The Leptothrix sheaths have excellent efficacy for dye adsorption. This material can be used as an effective, low-cost adsorbent. - Highlights: • Magnetic modification of Leptothrix sheaths using two methods is proposed. • Such magnetic material is an excellent adsorbent for Amido black 10B. • The magnetically modified sheaths can be easily separated by magnets.

  13. Application of Spray Foam Insulation Under Plywood and Oriented Strand Board Roof Sheathing

    Energy Technology Data Exchange (ETDEWEB)

    Grin, A. [Building Science Corporation, Somerville, MA (United States); Smegal, J. [Building Science Corporation, Somerville, MA (United States); Lstiburek, J. [Building Science Corporation, Somerville, MA (United States)

    2013-10-01

    Unvented roof strategies with open cell and closed cell spray polyurethane foam insulation sprayed to the underside of roof sheathing have been used since the mid-1990's to provide durable and efficient building enclosures. However, there have been isolated moisture related incidents reported anecdotally that raise potential concerns about the overall hygrothermal performance of these systems. This project involved hygrothermal modeling of a range of rainwater leakage and field evaluations of in-service residential roofs using spray foam insulation. All of the roof assemblies modeled exhibited drying capacity to handle minor rainwater leakage. All field evaluation locations of in-service residential roofs had moisture contents well within the safe range for wood-based sheathing. Explorations of eleven in-service roof systems were completed. The exploration involved taking a sample of spray foam from the underside of the roof sheathing, exposing the sheathing, then taking a moisture content reading. All locations had moisture contents well within the safe range for wood-based sheathing. One full-roof failure was reviewed, as an industry partner was involved with replacing structurally failed roof sheathing. In this case the manufacturer's investigation report concluded that the spray foam was installed on wet OSB based on the observation that the spray foam did not adhere well to the substrate and the pore structure of the closed cell spray foam at the ccSPF/OSB interface was indicative of a wet substrate.

  14. Development of Ti-sheathed MgB2 wires with high critical current density

    International Nuclear Information System (INIS)

    Liang, G; Fang, H; Hanna, M; Yen, F; Lv, B; Alessandrini, M; Keith, S; Hoyt, C; Tang, Z; Salama, K

    2006-01-01

    Working towards developing lightweight superconducting magnets for future space and other applications, we have successfully fabricated mono-core Ti-sheathed MgB 2 wires by the powder-in-tube method. The wires were characterized by magnetization, electrical resistivity, x-ray diffraction, scanning electron microscopy, and energy dispersive spectrometry measurements. The results indicate that the Ti sheath does not react with the magnesium and boron, and the present wire rolling process can produce MgB 2 wires with a superconducting volume fraction of at least 64% in the core. Using the Bean model, it was found that at 5 K, the magnetic critical current densities, J c , measured in magnetic fields of 0, 5, and 8 T are about 4.2 x 10 5 , 3.6 x 10 4 , and 1.4 x 10 4 A cm -2 , respectively. At 20 K and 0 T, the magnetic J c is about 2.4 x 10 5 A cm -2 . These results show that at zero and low fields, the values of the magnetic J c for Ti-sheathed MgB 2 wires are comparable with the best results available for the Fe-sheathed MgB 2 wires. At high fields, however, the J c for Ti-sheathed MgB 2 wires appears higher than that for the Fe-sheathed MgB 2 wires

  15. Magnetically modified sheaths of Leptothrix sp. as an adsorbent for Amido black 10B removal

    International Nuclear Information System (INIS)

    Angelova, Ralitsa; Baldikova, Eva; Pospiskova, Kristyna; Safarikova, Mirka; Safarik, Ivo

    2017-01-01

    The goal of this study was to assess the biosorption of Amido black 10B dye from aqueous solutions on magnetically modified sheaths of Leptothrix sp. in a batch system. The magnetic modification of the sheaths was performed using both microwave synthesized iron oxide nano- and microparticles and perchloric acid stabilized ferrofluid. The native and both magnetically modified sheaths were characterized by SEM. Various parameters significantly affecting the adsorption process, such as pH, contact time, temperature and initial concentration, were studied in detail using the adsorbent magnetized by both methods. The highest adsorption efficiency was achieved at pH 2. The maximum adsorption capacities of both types of magnetized material at room temperature were found to be 339.2 and 286.1 mg of dye per 1 g of ferrofluid modified and microwave synthesized particles modified adsorbent, respectively. Thermodynamic study of dye adsorption revealed a spontaneous and endothermic process in the temperature range between 279.15 and 313.15 K. The data were fitted to various equilibrium and kinetic models. Experimental data matched well with the pseudo-second-order kinetics and Freundlich isotherm model. The Leptothrix sheaths have excellent efficacy for dye adsorption. This material can be used as an effective, low-cost adsorbent. - Highlights: • Magnetic modification of Leptothrix sheaths using two methods is proposed. • Such magnetic material is an excellent adsorbent for Amido black 10B. • The magnetically modified sheaths can be easily separated by magnets.

  16. Evaluation of the equine digital flexor tendon sheath using diagnostic ultrasound and contrast radiography

    International Nuclear Information System (INIS)

    Redding, W.R.

    1994-01-01

    This study was designed to evaluate the normal anatomy of the digital flexor tendon sheath using contrast radiography and diagnostic ultrasound. Iodinated contrast medium was injected into eight cadaver limbs and the limbs immediately frozen. Lateromedial and dorsopalmar/plantar radiographs were made. These limps were then cut transversely and proximal to distal radiographs of each slab were made. This cross sectional contrast methodology allowed the visualization of the relative size and shape of the superficial and deep digital flexor tendons as well as the potential space taken by effusions of the digital flexor tendon sheath. The second part of the study used twelve live animals with normal digital flexor tendon sheaths. Ultrasonographic measurement of the structures of the digital flexor tendon sheath at each level were compiled. This documented the ability of diagnostic ultrasound to image: 1) the superficial and deep digital flexor tendons, 2) the proximal and distal ring of the manica flexoria, 3) the straight and oblique sesamoidean ligaments, and 4) the mesotendinous attachments to the superficial and deep flexor tendons. Iodinated contrast medium was then injected into the digital flexor tendon sheath and the ultrasonography repeated. These images were compared with those obtained from contrast radiography and prosections of twenty normal limbs. The iodinated contrast medium enhanced sonographic imaging of the structures of the digital tendon sheath, particularly the abaxial borders of the superficial digital flexor tendon branches and the mesotendinous attachments to the superficial and deep digital flexor tendons

  17. Balloon sheaths for gastrointestinal guidance and access: a preliminary phantom study

    Energy Technology Data Exchange (ETDEWEB)

    He, Xu; Shin, Ji Hoon; Kim, Hyo Cheol; Woo, Cheol Woong; Woo, Sung Ha; Choi, Won Chan; Kim, Jong Gyu; Lim, Jin Oh; Kim, Tae Hyung; Yoon, Chang Jin; Song, Ho Young [Univerisyt of Ulsan College of Medicine, Seoul (Korea, Republic of); Kang, Wee Chang [Daejeon University, Daejeon (Korea, Republic of)

    2005-09-15

    We wanted to evaluate the feasibility and usefulness of a newly designed balloon sheath for gastrointestinal guidance and access by conducting a phantom study. The newly designed balloon sheath consisted of an introducer sheath and a supporting balloon. A coil catheter was advanced over a guide wire into two gastroduodenal phantoms (one was with stricture and one was without stricture); group I was without a balloon sheath, group II was with a deflated balloon sheath, and groups III and IV were with an inflated balloon and with the balloon in the fundus and body, respectively. Each test was performed for 2 minutes and it was repeated 10 times in each group by two researchers, and the positions reached by the catheter tip were recorded. Both researchers had better performances with both phantoms in order of group IV, III, II and I. In group IV, both researchers advanced the catheter tip through the fourth duodenal segment in both the phantoms. In group I, however, the catheter tip never reached the third duodenal segment in both the phantoms by both the researchers. The numeric values for the four study groups were significantly different for both the phantoms ({rho} < 0.001). A significant difference was also found between group III and IV for both phantoms ({rho} < 0.001). The balloon sheath seems to be feasible for clinical use, and it has good clinical potential for gastrointestinal guidance and access, particularly when the inflated balloon is placed in the gastric body.

  18. Electromagnetic Transients on an Underground Cable due to a Lightning Current Flowing into the Metallic Sheath

    Science.gov (United States)

    Ametani, Akihiro; Nagaoka, Naoto; Miyazaki, Daisuke; Taki, Norikazu

    This paper has investigated surge propagation and overvoltages on a coaxial cable when a lightning current flows into the metallic sheath based on experiments, EMTP simulations and analytical calculations. At the instance of the current flowing into the sheath, the core voltage becomes the same as the sheath voltage, which is given as a product of the sheath surge impedance and a half the current, following the theory of electrostatic shield. Thus no voltage difference appears between the core and the sheath across the insulator. When a traveling wave arrives at a transition point, i.e. cable termination, an insulating or crossbonding joint, the voltages change suddenly and a significant voltage appears across the insulator. An EMTP simulation shows that the overvoltage across the insulator exceeds 1200kV at a crossbonded node on a 400kV underground cable when an ac source voltage is in the opposite polarity of the lightning surge voltage on the sheath and the inductance of a crossbonding lead wire is taken into account. The high overvoltage appears in a narrow region of the cable between the current injected node and the crossbonded node due to traveling wave reflection between the nodes. The phenomenon investigated may occur if there exists a pinhole or a watertree on an underground cable.

  19. Laser-Induced Fluorescence for Sheath Characterization in Low-Density Argon Plasmas

    Science.gov (United States)

    Englesbe, Alexander C.; Sawlani, Kapil U.; Foster, John E.

    2013-09-01

    Laser-induced fluorescence (LIF) spectroscopy has become a standard non-intrusive diagnostic technique for determining the energies and concentrations of ion and neutral species in plasmas. A limitation of this technique, however, is the small signal-to-noise ratio incurred when interrogating relatively low-density plasmas. This problem is exacerbated when examining regions such as the sheath at an electrode immersed in the plasma. If ion energetics within the sheath are of interest, then in principle thicker sheaths are desirable in that for a given laser spot size, the potential structure can be inferred with high resolution. We present a methodology for accomplishing LIF in the sheath of a low-temperature argon plasma with an electron density of the order 107 -108 cm-3. This diagnostic is being developed for the purpose of studying the effect of secondary electron emission on sheath potential behavior in low-density plasmas. The plasma in this study is produced in a multipole ring-cusp ion source. A tunable diode laser excites the Ar II transition at 668.61 nm, which fluoresces at 442.72 nm. The LIF measurements of the ion density are corroborated with electrostatic probes at fixed locations, and the ion velocity distribution within the sheath is determined. Work supported by AFOSR Grant No. FA9550-09-1-0695.

  20. Balloon sheaths for gastrointestinal guidance and access: a preliminary phantom study

    International Nuclear Information System (INIS)

    He, Xu; Shin, Ji Hoon; Kim, Hyo Cheol; Woo, Cheol Woong; Woo, Sung Ha; Choi, Won Chan; Kim, Jong Gyu; Lim, Jin Oh; Kim, Tae Hyung; Yoon, Chang Jin; Song, Ho Young; Kang, Wee Chang

    2005-01-01

    We wanted to evaluate the feasibility and usefulness of a newly designed balloon sheath for gastrointestinal guidance and access by conducting a phantom study. The newly designed balloon sheath consisted of an introducer sheath and a supporting balloon. A coil catheter was advanced over a guide wire into two gastroduodenal phantoms (one was with stricture and one was without stricture); group I was without a balloon sheath, group II was with a deflated balloon sheath, and groups III and IV were with an inflated balloon and with the balloon in the fundus and body, respectively. Each test was performed for 2 minutes and it was repeated 10 times in each group by two researchers, and the positions reached by the catheter tip were recorded. Both researchers had better performances with both phantoms in order of group IV, III, II and I. In group IV, both researchers advanced the catheter tip through the fourth duodenal segment in both the phantoms. In group I, however, the catheter tip never reached the third duodenal segment in both the phantoms by both the researchers. The numeric values for the four study groups were significantly different for both the phantoms (ρ < 0.001). A significant difference was also found between group III and IV for both phantoms (ρ < 0.001). The balloon sheath seems to be feasible for clinical use, and it has good clinical potential for gastrointestinal guidance and access, particularly when the inflated balloon is placed in the gastric body

  1. Review of opening switch technology

    International Nuclear Information System (INIS)

    Kristiansen, M.; Schoenbach, K.M.; Schaefer, G.

    1984-01-01

    Review of opening switch technology is given. Classification of open switches applied in pulsed power technology is presented. The most familiar opening switches are fuses. It is shown that a strong oxidizer (H 2 O 2 in water), especially in combination with wires of Al, increases the maximum voltage. Thermally driven opening switches are the result of attempts to achive the speed and economy of fuse opening switches but with added advantage of repetitive operation. The search for coordinate materials for this type of opening switch is in its infancy and it is difficult to predict how successful such a switch may be. Explosive opening switches offer the possibility of precise timing and permit the delay before explosion to be controlled independently of current flowing through the switch. Plasma guns, dense plasma focus and MHD switches are also considered. Diffuse discharge opening switches are attractive for repetitive operation. The plasma erosion switch operates on a very short time scale of 10 ns to 100 ns, both to regard to conduction and opening times

  2. Anodic oxidation of Ta/Fe alloys

    International Nuclear Information System (INIS)

    Mato, S.; Alcala, G.; Thompson, G.E.; Skeldon, P.; Shimizu, K.; Habazaki, H.; Quance, T.; Graham, M.J.; Masheder, D.

    2003-01-01

    The behaviour of iron during anodizing of sputter-deposited Ta/Fe alloys in ammonium pentaborate electrolyte has been examined by transmission electron microscopy, Rutherford backscattering spectroscopy, glow discharge optical emission spectroscopy and X-ray photoelectron spectroscopy. Anodic films on Ta/1.5 at.% Fe, Ta/3 at.% Fe and Ta/7 at.% Fe alloys are amorphous and featureless and develop at high current efficiency with respective formation ratios of 1.67, 1.60 and 1.55 nm V -1 . Anodic oxidation of the alloys proceeds without significant enrichment of iron in the alloy in the vicinity of the alloy/film interface and without oxygen generation during film growth, unlike the behaviour of Al/Fe alloys containing similar concentrations of iron. The higher migration rate of iron species relative to that of tantalum ions leads to the formation of an outer iron-rich layer at the film surface

  3. Abacus switch: a new scalable multicast ATM switch

    Science.gov (United States)

    Chao, H. Jonathan; Park, Jin-Soo; Choe, Byeong-Seog

    1995-10-01

    This paper describes a new architecture for a scalable multicast ATM switch from a few tens to thousands of input ports. The switch, called Abacus switch, has a nonblocking memoryless switch fabric followed by small switch modules at the output ports; the switch has input and output buffers. Cell replication, cell routing, output contention resolution, and cell addressing are all performed distributedly in the Abacus switch so that it can be scaled up to thousnads input and output ports. A novel algorithm has been proposed to resolve output port contention while achieving input and output ports. A novel algorithm has been proposed to reolve output port contention while achieving input buffers sharing, fairness among the input ports, and multicast call splitting. The channel grouping concept is also adopted in the switch to reduce the hardware complexity and improve the switch's throughput. The Abacus switch has a regular structure and thus has the advantages of: 1) easy expansion, 2) relaxed synchronization for data and clock signals, and 3) building the switch fabric using existing CMOS technology.

  4. Silicon Whisker and Carbon Nanofiber Composite Anode

    Science.gov (United States)

    Lang, Christopher M.

    2015-01-01

    Phase II Objectives: Demonstrate production levels of grams per batch; Achieve full cell anode capacity of greater than 1,000 mAh/g at a charge rate of 10 (C/10) and 0 degree C; Establish a full cell cycle life of over 300 cycles; Display an operating temperature of negative 30 degrees C to plus 30 degrees C; Demonstrate a rate capability of C/5 or higher; Deliver to NASA three 2.5 Ah cells (energy density greater than 220 Wh/kg); Exhibit the safety features of the anode and full cells; Design a 1 kWh prismatic battery pack.

  5. The effect of ethylene glycol on pore arrangement of anodic aluminium oxide prepared by hard anodization

    Science.gov (United States)

    Guo, Yang; Zhang, Li; Han, Mangui; Wang, Xin; Xie, Jianliang; Deng, Longjiang

    2018-03-01

    The influence of the addition of ethylene glycol (EG) on the pore self-ordering process in anodic aluminium oxide (AAO) membranes prepared by hard anodization (HA) was investigated. It was illustrated that EG has a substantial effect on the pore arrangement of AAO, and it was found that a smaller pore size can be obtained with an EG concentration reaching 20 wt% in aqueous electrolyte. The number of estimated defects of AAO increases significantly with an increase in EG concentration to 50 wt%. Excellent ordering of pores was realized when the samples were anodized in the 30 wt%-EG-containing aqueous electrolyte.

  6. Silicon Whisker and Carbon Nanofiber Composite Anode, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Physical Sciences Inc. (PSI) proposes to develop a silicon whisker and carbon nanofiber composite anode for lithium ion batteries on a Phase I program. This anode...

  7. Fractionated Stereotactic Radiotherapy in Patients With Optic Nerve Sheath Meningioma

    Energy Technology Data Exchange (ETDEWEB)

    Paulsen, Frank, E-mail: frank.paulsen@med.uni-tuebingen.de [Department of Radiation Oncology, University of Tuebingen, Tuebingen (Germany); Doerr, Stefan [Department of Radiation Oncology, University of Tuebingen, Tuebingen (Germany); Wilhelm, Helmut [Department of Ophthalmology, University of Tuebingen, Tuebingen (Germany); Becker, Gerd [Department of Radiation Oncology, Klinik am Eichert, Goeppingen (Germany); Bamberg, Michael [Department of Radiation Oncology, University of Tuebingen, Tuebingen (Germany); Classen, Johannes [Department of Radiation Oncology, St. Vincentius-Kliniken, Karlsruhe (Germany)

    2012-02-01

    Purpose: To evaluate the effectiveness of fractionated stereotactic radiotherapy (SFRT) in the treatment of optic nerve sheath meningioma (ONSM). Methods and Materials: Between 1993 and 2005, 109 patients (113 eyes) with primary (n = 37) or secondary (n = 76) ONSM were treated according to a prospective protocol with SFRT to a median dose of 54 Gy. All patients underwent radiographic, ophthalmologic, and endocrine analysis before and after SFRT. Radiographic response, visual control, and late side effects were endpoints of the analysis. Results: Median time to last clinical, radiographic, and ophthalmologic follow up was 30.2 months (n = 113), 42.7 months (n = 108), and 53.7 months (n = 91), respectively. Regression of the tumor was observed in 5 eyes and progression in 4 eyes, whereas 104 remained stable. Visual acuity improved in 12, deteriorated in 11, and remained stable in 68 eyes. Mean visual field defects reduced from 33.6% (n = 90) to 17.8% (n = 56) in ipsilateral and from 10% (n = 94) to 6.7% (n = 62) in contralateral eyes. Ocular motility improved in 23, remained stable in 65, and deteriorated in 3 eyes. Radiographic tumor control was 100% at 3 years and 98% at 5 years. Visual acuity was preserved in 94.8% after 3 years and in 90.9% after 5 years. Endocrine function was normal in 90.8% after 3 years and in 81.3% after 5 years. Conclusions: SFRT represents a highly effective treatment for ONSM. Interdisciplinary counseling of the patients is recommended. Because of the high rate of preservation of visual acuity we consider SFRT the standard approach for the treatment of ONSM. Prolonged observation is warranted to more accurately assess late visual impairment. Moderate de-escalation of the radiation dose might improve the preservation of visual acuity and pituitary gland function.

  8. Optical fiber switch

    Science.gov (United States)

    Early, James W.; Lester, Charles S.

    2002-01-01

    Optical fiber switches operated by electrical activation of at least one laser light modulator through which laser light is directed into at least one polarizer are used for the sequential transport of laser light from a single laser into a plurality of optical fibers. In one embodiment of the invention, laser light from a single excitation laser is sequentially transported to a plurality of optical fibers which in turn transport the laser light to separate individual remotely located laser fuel ignitors. The invention can be operated electro-optically with no need for any mechanical or moving parts, or, alternatively, can be operated electro-mechanically. The invention can be used to switch either pulsed or continuous wave laser light.

  9. Beyond the switch

    DEFF Research Database (Denmark)

    Aliakseyeu, Dzmitry; Meerbeek, Bernt; Mason, Jon

    2014-01-01

    The commercial introduction of connected lighting that can be integrated with sensors and other devices is opening up new possibilities in creating responsive and intelligent environments. The role of lighting in such systems goes beyond simply functional illumination. In part due to the large...... is to explore new ways of interacting with light where lighting can not only be switched on or off, but is an intelligent system embedded in the environment capable of creating a variety of effects. The connectivity between multiple systems and other ecosystems, for example when transitioning from your home...... and established lighting network, and with the advent of the LED, new types of lighting output are now possible. However, the current approach for controlling such systems is to simply replace the light switch with a somewhat more sophisticated smartphone-based remote control. The focus of this workshop...

  10. Laser activated superconducting switch

    International Nuclear Information System (INIS)

    Wolf, A.A.

    1976-01-01

    A superconducting switch or bistable device is described consisting of a superconductor in a cryogen maintaining a temperature just below the transition temperature, having a window of the proper optical frequency band for passing a laser beam which may impinge on the superconductor when desired. The frequency of the laser is equal to or greater than the optical absorption frequency of the superconducting material and is consistent with the ratio of the gap energy of the switch material to Planck's constant, to cause depairing of electrons, and thereby normalize the superconductor. Some embodiments comprise first and second superconducting metals. Other embodiments feature the two superconducting metals separated by a thin film insulator through which the superconducting electrons tunnel during superconductivity

  11. Coulomb Blockade Plasmonic Switch.

    Science.gov (United States)

    Xiang, Dao; Wu, Jian; Gordon, Reuven

    2017-04-12

    Tunnel resistance can be modulated with bias via the Coulomb blockade effect, which gives a highly nonlinear response current. Here we investigate the optical response of a metal-insulator-nanoparticle-insulator-metal structure and show switching of a plasmonic gap from insulator to conductor via Coulomb blockade. By introducing a sufficiently large charging energy in the tunnelling gap, the Coulomb blockade allows for a conductor (tunneling) to insulator (capacitor) transition. The tunnelling electrons can be delocalized over the nanocapacitor again when a high energy penalty is added with bias. We demonstrate that this has a huge impact on the plasmonic resonance of a 0.51 nm tunneling gap with ∼70% change in normalized optical loss. Because this structure has a tiny capacitance, there is potential to harness the effect for high-speed switching.

  12. Practical switching power supply design

    CERN Document Server

    Brown, Martin C

    1990-01-01

    Take the ""black magic"" out of switching power supplies with Practical Switching Power Supply Design! This is a comprehensive ""hands-on"" guide to the theory behind, and design of, PWM and resonant switching supplies. You'll find information on switching supply operation and selecting an appropriate topology for your application. There's extensive coverage of buck, boost, flyback, push-pull, half bridge, and full bridge regulator circuits. Special attention is given to semiconductors used in switching supplies. RFI/EMI reduction, grounding, testing, and safety standards are also deta

  13. Python Switch Statement

    Directory of Open Access Journals (Sweden)

    2008-06-01

    Full Text Available The Python programming language does not have a built in switch/case control structure as found in many other high level programming languages. It is thought by some that this is a deficiency in the language, and the control structure should be added. This paper demonstrates that not only is the control structure not needed, but that the methods available in Python are more expressive than built in case statements in other high level languages.

  14. Stability and reliability of anodic biofilms under different feedstock conditions: Towards microbial fuel cell sensors

    Directory of Open Access Journals (Sweden)

    Jiseon You

    2015-12-01

    Full Text Available Stability and reliability of microbial fuel cell anodic biofilms, consisting of mixed cultures, were investigated in a continuously fed system. Two groups of anodic biofilm matured with different substrates, acetate and casein for 20–25 days, reached steady states and produced 80–87 μW and 20–29 μW consistently for 3 weeks, respectively. When the substrates were swapped, the casein-enriched group showed faster response to acetate and higher power output, compared to the acetate-enriched group. Also when the substrates were switched back to their original groups, the power output of both groups returned to the previous levels more quickly than when the substrates were swapped the first time. During the substrate change, both MFC groups showed stable power output once they reached their steady states and the output of each group with different substrates was reproducible within the same group. Community level physiological profiling also revealed the possibility of manipulating anodic biofilm metabolisms through exposure to different feedstock conditions.

  15. Nanomechanics of flexoelectric switching

    Science.gov (United States)

    Očenášek, J.; Lu, H.; Bark, C. W.; Eom, C. B.; Alcalá, J.; Catalan, G.; Gruverman, A.

    2015-07-01

    We examine the phenomenon of flexoelectric switching of polarization in ultrathin films of barium titanate induced by a tip of an atomic force microscope (AFM). The spatial distribution of the tip-induced flexoelectricity is computationally modeled both for perpendicular mechanical load (point measurements) and for sliding load (scanning measurements), and compared with experiments. We find that (i) perpendicular load does not lead to stable ferroelectric switching in contrast to the load applied in the sliding contact load regime, due to nontrivial differences between the strain distributions in both regimes: ferroelectric switching for the perpendicular load mode is impaired by a strain gradient inversion layer immediately underneath the AFM tip; while for the sliding load regime, domain inversion is unimpaired within a greater material volume subjected to larger values of the mechanically induced electric field that includes the region behind the sliding tip; (ii) beyond a relatively small value of an applied force, increasing mechanical pressure does not increase the flexoelectric field inside the film, but results instead in a growing volume of the region subjected to such field that aids domain nucleation processes; and (iii) the flexoelectric coefficients of the films are of the order of few nC/m, which is much smaller than for bulk BaTi O3 ceramics, indicating that there is a "flexoelectric size effect" that mirrors the ferroelectric one.

  16. "Platform switching": Serendipity

    Directory of Open Access Journals (Sweden)

    N Kalavathy

    2014-01-01

    Full Text Available Implant dentistry is the latest developing field in terms of clinical techniques, research, material science and oral rehabilitation. Extensive work is being done to improve the designing of implants in order to achieve better esthetics and function. The main drawback with respect to implant restoration is achieving good osseointegration along with satisfactory stress distribution, which in turn will improve the prognosis of implant prosthesis by reducing the crestal bone loss. Many concepts have been developed with reference to surface coating of implants, surgical techniques for implant placement, immediate and delayed loading, platform switching concept, etc. This article has made an attempt to review the concept of platform switching was in fact revealed accidentally due to the nonavailability of the abutment appropriate to the size of the implant placed. A few aspect of platform switching, an upcoming idea to reduce crestal bone loss have been covered. The various methods used for locating and preparing the data were done through textbooks, Google search and related articles.

  17. Silicon-Based Anode and Method for Manufacturing the Same

    Science.gov (United States)

    Yushin, Gleb Nikolayevich (Inventor); Luzinov, Igor (Inventor); Zdyrko, Bogdan (Inventor); Magasinski, Alexandre (Inventor)

    2017-01-01

    A silicon-based anode comprising silicon, a carbon coating that coats the surface of the silicon, a polyvinyl acid that binds to at least a portion of the silicon, and vinylene carbonate that seals the interface between the silicon and the polyvinyl acid. Because of its properties, polyvinyl acid binders offer improved anode stability, tunable properties, and many other attractive attributes for silicon-based anodes, which enable the anode to withstand silicon cycles of expansion and contraction during charging and discharging.

  18. The contents of macromolecule solutes in flexor tendon sheath fluid and their relation to synovial fluid. A quantitative analysis.

    Science.gov (United States)

    Hagberg, L; Heinegård, D; Ohlsson, K

    1992-04-01

    The importance of synovial environment for minimal adhesion formation in flexor tendon healing has recently gained attention. Various techniques have been used to restore an injured synovial tendon sheath. Therefore a quantitative analysis of flexor tendon sheath fluid is of interest to increase our knowledge about the specific synovial milieu and to evaluate the success of different types of sheath reconstructions from a biochemical point of view. Samples of tendon sheath fluid from trigger digits and tendon sheaths containing ganglions have been assayed for contents of hyaluronic acid and proteins of different molecular weights. The results show concentrations of hyaluronate and several proteins similar to those in normal joint fluid. These results indicate that flexor tendon sheath fluid has a character similar to synovial fluid of joints and apparently has specific functions such as soft tissue lubrication and nutrition of avascular tendon tissue.

  19. Comparison of Ultrasound-Guided to Fluoroscopy-Guided Biceps Tendon Sheath Therapeutic Injection.

    Science.gov (United States)

    Petscavage-Thomas, Jonelle; Gustas, Cristy

    2016-10-01

    Biceps tendinitis is a source of anterior shoulder pain and is amenable to therapeutic injection. Studies have shown greater accuracy with image-guided compared to unguided injection of the biceps tendon sheath. There is no literature comparing ultrasound-guided to fluoroscopy-guided biceps tendon sheath injection. The purpose of this study was to compare clinical outcomes, complication rates, procedure success rates, and financial costs of the two imaging-guided methods. A 10-year retrospective review of the picture archiving and communication system was performed to identify patients who underwent image-guided proximal biceps tendon sheath injection. Two radiologists reviewed the picture archiving and communication system and clinical notes to record pain relief, complications, fluoroscopy time, first-pass success rate (defined as injection into the sheath on the first needle pass), final success rate (needle placement in the tendon sheath on the final needle pass), and average costs. Fifty fluoroscopy-guided and 53 ultrasound-guided cases were identified. There was no statistically significant difference in pain relief or complications. The first-pass success rate was 90.6% for ultrasound compared to 74.0% for fluoroscopy. The final-pass success rate was 98.2% for ultrasound versus 92.0% for fluoroscopy. The mean fluoroscopy time was 57.6 seconds. Ultrasound showed preinjection abnormalities of the biceps tendon in 47.5% of cases. Compared to fluoroscopy-guided biceps tendon sheath injection, ultrasound had higher initial- and final-pass success rates, visualized abnormalities before injection, and had similar pain relief and complication rates. Ultrasound is more accurate and has greater diagnostic benefits than unguided or fluoroscopy-guided biceps tendon sheath injection.

  20. Impact of introducer sheath coating on endothelial function in humans after transradial coronary procedures.

    Science.gov (United States)

    Dawson, Ellen A; Rathore, Sudhir; Cable, N Timothy; Wright, D Jay; Morris, John L; Green, Daniel J

    2010-04-01

    The aim of this study was to compare the impact of transradial catheterization with hydrophilic-coated catheter sheaths versus uncoated sheaths on NO-mediated endothelial-dependent and -independent vasodilator function. Thirty-five subjects undergoing transradial catheterization were recruited and assessed before and the day after catheterization. A subgroup was also assessed 3 to 4 months after catheterization. Subjects received hydrophilic-coated sheaths (n=15) or uncoated sheaths (n=20). Radial artery flow-mediated dilatation and endothelium- and NO-dependent arterial dilatation were assessed within the region of sheath placement. Glyceryl trinitrate endothelium-independent NO-mediated function was also assessed. The noncatheterized arm provided an internal control. Flow-mediated dilatation in the catheterized arm decreased from 10.3+/-3.8% to 5.3+/-3.3% and 8.1+/-2.4% to 5.2+/-3.7% in the coated and uncoated groups, respectively (P<0.01). These values returned toward baseline levels approximately 3 months later (coated, 6.4+/-1.4%; uncoated, 9.4+/-4.1%; P<0.05) versus postprocedure. Glyceryl trinitrate decreased from 14.8+/-7.2% to 9.5+/-4.1% (P<0.05) in the coated group and from 12.2+/-4.6% to 7.5+/-4.2% (P<0.01) in the uncoated group. Values returned to baseline at approximately 3 months (coated, 16.6+/-5.6%; uncoated, 12.1+/-3.9%; P<0.05). There was no difference in the magnitude of decrease in flow-mediated dilatation or glyceryl trinitrate between coated and uncoated groups. No changes in function occurred in the noncatheterized arm. Placement of a catheter sheath inside the radial artery disrupts vasodilator function, which recovers after 3 months. No differences were evident between hydrophilic-coated and uncoated sheaths.

  1. Compression test of cold-formedsteel perforated profile with steel sheathing

    Directory of Open Access Journals (Sweden)

    Shamanin Aleksandr Yur’evich

    2015-05-01

    Full Text Available The subject of this paper is the stability and strength of cold-formed and perforated steel sigma-section columns with steel sheathing of different thickness. Ceilings with and without steel sheathing of different thickness are tested to failure in compression on a laboratory machine, which was based on a manual hydraulic jack. Series of 4 experiments with full-scale walls (2.5 m height were carried out. Also, for examination of the role of boundary conditions, the sheet in a ceiling is either left free or connected to base with screws.In civil engineering there are many experiments and methodologies for calculating the strength and buckling of ceiling with the sheathing of various materials, such as oriented strand board and gypsum board. However, for producing superstructures of ships the materials with high plastic properties and strength characteristics are required. For example steel possesses such properties. It was the main reason for conducting a series of experiments and studying the behavior of cold-formed steel columns with steel sheathing. During the experiments the deformation of the cross-section of three equally spaced cross sections was determined, as well as the axial deformation of the central column in the ceiling with steel sheathing.The test results showed the influence of the thickness of sheathing and boundary condition of a sheet on the strength and buckling of ceiling. According to the results of the tests it is necessary to evaluate the impact of the sheathing made of different materials and if necessary to carry out further tests.

  2. Hollow Anode Cascading Plasma Focus | Alabraba | Journal of the ...

    African Journals Online (AJOL)

    Using the 3-phase model for each focus event, the 9-phase, two solid disc auxiliary anode cascading plasma focus has been extended to include holes at the center of each cascade anode (hereafter referred to as hollow anode cascading focus) with a view of increasing the neutron yield with each focus event. Results ...

  3. Anode heat transfer in a constricted tube arc.

    Science.gov (United States)

    Lukens, L. A.; Incropera, F. P.

    1971-01-01

    The complex energy exchange mechanisms occurring on the most severely heated component of an arc constrictor, the anode, have been investigated. Measurements performed to determine the anode heat flux for a cascade, atmospheric argon arc of the Maecker type are described. The results are used to check the validity of an existing anode heat transfer model.

  4. Anodization of Aluminium using a fast two-step process

    Indian Academy of Sciences (India)

    the electrolyte for the first anodization to form pits on. Al substrate, while in second anodization these pits act as the pattern for nanopore formation.26 Nanoporous alumina is used in the development of thermoelectric devices using metamaterials and for energy harvest- ing. Anodized magnetic nanohole arrays are used in.

  5. Vibration interference analysis and verification of micro-fluidic inertial switch

    Directory of Open Access Journals (Sweden)

    Liu Tingting

    2014-02-01

    Full Text Available The micro-fluidic inertial switch based on liquid metal utilizes the moving mercury droplet to close the switch under the action of acceleration, which is characterized by no moving parts, small contact resistance, long service life and large current. In addition to the requirement of response time, accuracy and reliability, the micro-fluidic inertial switch needs to overcome the impact of the ambient vibration. The influence of the ambient vibration on the performance of switch is investigated by loading pulse or sinusoidal interference signals in the X, Y and Z direction. The numerical results suggest that the performance of micro-fluidic inertial switch is greatly affected by impact interference signal in X sensitive direction as compared with low frequency harmonic signal. If the impact signal with high amplitude lasts only for a short time, the wrong operation might also occur. The interference signals in insensitive direction have a relatively small impact on the performance of switch, and the impact of interference signal can be reduced by reasonable structural design. Finally, anodic bonding, deep reactive ion etching (DRIE and sputtering technique are adopted to fabricate the micro-fluidic inertial switch. The acceleration threshold of the prototype is tested. The experiment results agree with the numerical results, which indicate that the simulation method is valid.

  6. Fine structure of modal focusing effect in a three dimensional plasma-sheath-lens formed by disk electrodes

    DEFF Research Database (Denmark)

    Stamate, Eugen; Yamaguchi, Masahito

    2015-01-01

    Modal and discrete focusing effects associated with three-dimensional plasma-sheath-lenses show promising potential for applications in ion beam extraction, mass spectrometry, plasma diagnostics and for basic studies of plasma sheath. The ion focusing properties can be adjusted by controlling the...... to the sheath thickness and can be used to monitor very small changes in plasma parameters. Three dimensional simulations are found to be in very good agreement with experiments....

  7. Coating of Zircaloy sheaths with silica glass using the Sol-Gel technique for protection against oxidation

    International Nuclear Information System (INIS)

    De Sanctis, O.; Pellegri, N.; Gomez, L.

    1990-01-01

    With the aim of improving corrosion resistance of Zircaloy, a few Zircaloy sheaths were covered with vitreous silica. Deposition was made by dip coating in tetraetilortosilicate (TEOS) solutions and later densification treatment at 500 degrees C. Oxidation tests were performed and compared with sheaths not covered with silica. As a result, an effective increase in the resistance to dry oxidation was found in sheaths which had been protected. The coating-Zircaloy interface was studied using XPS (scanner). (Author). 6 refs., 3 figs

  8. Silicon Whisker and Carbon Nanofiber Composite Anode

    Science.gov (United States)

    Ma, Junqing (Inventor); Newman, Aron (Inventor); Lennhoff, John (Inventor)

    2015-01-01

    A carbon nanofiber can have a surface and include at least one crystalline whisker extending from the surface of the carbon nanofiber. A battery anode composition can be formed from a plurality of carbon nanofibers each including a plurality of crystalline whiskers.

  9. Growth of anodic films on niobium

    International Nuclear Information System (INIS)

    Gomes, M.A.B.; Bulhoes, L.O.S.

    1988-01-01

    The analysis of the response of the galvanostatic growth of anodic films on niobium metal in aqueous solutions is shown. The first spark voltage showed a dependence upon value of current density that could be explained as the incorporation of anions into the film. (M.J.C.) [pt

  10. Anode materials for lithium-ion batteries

    Science.gov (United States)

    Sunkara, Mahendra Kumar; Meduri, Praveen; Sumanasekera, Gamini

    2014-12-30

    An anode material for lithium-ion batteries is provided that comprises an elongated core structure capable of forming an alloy with lithium; and a plurality of nanostructures placed on a surface of the core structure, with each nanostructure being capable of forming an alloy with lithium and spaced at a predetermined distance from adjacent nanostructures.

  11. Linear sweep anodic stripping voltammetry: Determination of ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 127; Issue 6. Linear sweep anodic stripping voltammetry: Determination of Chromium (VI) using synthesized gold nanoparticles modified screen-printed electrode. Salamatu Aliyu Tukur Nor Azah Yusof Reza Hajian. Regular Articles Volume 127 Issue 6 June 2015 pp ...

  12. Hybrid anode for semiconductor radiation detectors

    Science.gov (United States)

    Yang, Ge; Bolotnikov, Aleksey E; Camarda, Guiseppe; Cui, Yonggang; Hossain, Anwar; Kim, Ki Hyun; James, Ralph B

    2013-11-19

    The present invention relates to a novel hybrid anode configuration for a radiation detector that effectively reduces the edge effect of surface defects on the internal electric field in compound semiconductor detectors by focusing the internal electric field of the detector and redirecting drifting carriers away from the side surfaces of the semiconductor toward the collection electrode(s).

  13. Characterization of nanopores ordering in anodic alumina

    DEFF Research Database (Denmark)

    Mátéfi-Tempfli, Stefan; Mátéfi-Tempfli, M.; Piraux, L.

    2008-01-01

    A simple characterization method of the ordering of the nanopores is described for nanoporous anodized aluminium oxides. The method starts with image analysis on scanning electron microscopy representations for the purpose to find repetitive shapes and their centres, i.e. nanopores. Then triangles...

  14. Quantitative relationship between nanotube length and anodizing current during constant current anodization

    International Nuclear Information System (INIS)

    Zhang, Yulian; Cheng, Weijie; Du, Fei; Zhang, Shaoyu; Ma, Weihua; Li, Dongdong; Song, Ye; Zhu, Xufei

    2015-01-01

    Highlights: • Ti anodization was performed by constant current rather than constant voltage. • The nanotube length was controlled by ionic current rather than dissolution current. • Electronic current can be estimated by the nanotube length and the anodizing current. • Dissolution reaction hardly contributes electric current across the barrier layer. - Abstract: The growth kinetics of anodic TiO 2 nanotubes (ATNTs) still remains unclear. ATNTs are generally fabricated under potentiostatic conditions rather than galvanostatic ones. The quantitative relationship between nanotube length and anodizing current (J total ) is difficult to determine, because the variable J total includes ionic current (J ion ) (also called oxide growth current J grow =J ion ) and electronic current (J e ), which cannot be separated from each other. One successful approach to achieve this objective is to use constant current anodization rather than constant voltage anodization, that is, through quantitative comparison between the nanotube length and the known J total during constant current anodization, we can estimate the relative magnitudes of J grow and J e . The nanotubes with lengths of 1.24, 2.23, 3.51 and 4.70 μm, were formed under constant currents (J total ) of 15, 20, 25 and 30 mA, respectively. The relationship between nanotube length (y) and anodizing current (x =J total =J grow +J e ) can be expressed by a fitting equation: y=0.23(x-10.13), from which J grow (J grow = x -10.13) and J e (∼10.13 mA) could be inferred under the present conditions. Meanwhile, the same conclusion could also be deduced from the oxide volume data. These results indicate that the nanotube growth is attributed to the oxide growth current rather than the dissolution current.

  15. Structure and function relationships in the colon. The role of the pericryptal sheath

    Energy Technology Data Exchange (ETDEWEB)

    Thiagarajah, J.R

    2001-07-01

    High doses of ionising radiation result in a reduction in fluid absorption in rat descending colon after four days. This reduction in fluid absorption may be due to increased leakiness of the crypt epithelial cells and loss of the pericryptal sheath. There is loss of the cell adhesion molecules E-cadherin and OB cadherin from the crypt epithelial cells and the pericryptal sheath after 8Gy ionising radiation. Smooth muscle actin staining indicated that the pericryptal sheath was disrupted after radiation. These changes were preceded by dose dependent increases in the apoptotic signalling proteins cytochrome c and caspase-3. Loss of the pericryptal sheath and loss of crypt epithelial adhesion coincides with increased permeability as shown by increased leakage of FITC dextran in radiated crypts. Further investigation of cytochrome c release in Caco-2 cells after targeted radiation with a charged particle microbeam showed that it may be a 'bystander response' and that an important initiating event in release is the generation of free radicals. Low dietary Na{sup +} causes an upregulation of plasma angiotensin II and aldosterone and increased fluid absorption in the colon. Previously work on aldosterone effects in the colon has concentrated on the epithelial Na{sup +} channels and pumps. Angiotensin II has also been shown to upregulate various cytokines in the heart and other tissues. Investigation of the effects of low Na{sup +} diet on the pericryptal sheath in rat descending colon showed increases in angiotensin II and transforming Growth factor {beta} receptors and collagen type IV and smooth muscle actin. The increases in descending colonic sheath matrix and myofibroblast microfilaments were not seen in the caecum and suggest that an important factor in increased fluid absorption after low Na{sup +} diet may be increased barrier function of the pericryptal sheath. Similar changes to the sheath components also occur at 4-11 days after ionising radiation

  16. Biomechanics of the Optic Nerve Sheath in VIIP Syndrome

    Science.gov (United States)

    Ethier, C. Ross; Raykin, Julia; Gleason, Rudy; Mulugeta, Lealem; Myers, Jerry; Nelson, Emily; Samuels, Brian C.

    2014-01-01

    Long-duration space flight carries the risk of developing Visual Impairment and Intracranial Pressure (VIIP) syndrome, a spectrum of ophthalmic changes including posterior globe flattening, choroidal folds, distension of the optic nerve sheath (ONS), optic nerve kinking and potentially permanent degradation of visual function. The slow onset of VIIP, its chronic nature, and certain clinical features strongly suggest that biomechanical factors acting on the ONS play a role in VIIP. Here we measure several relevant ONS properties needed to model VIIP biomechanics. The ONS (meninges) of fresh porcine eyes (n7) was reflected, the nerve proper was truncated near the sclera, and the meninges were repositioned to create a hollow cylinder of meningeal connective tissue attached to the posterior sclera. The distal end was cannulated, sealed, and pressure clamped (mimicking cerebrospinal fluid [CSF] pressure), while the eye was also cannulated for independent control of intraocular pressure (IOP). The meninges were inflated (CSF pressure cycling 7-50 mmHg) while ONS outer diameter was imaged. In another set of experiments (n4), fluid permeation rate across the meninges was recorded by observing the drainage of an elevated fluid reservoir (30 mmHg) connected to the meninges. The ONS showed behavior typical of soft tissues: viscoelasticity, with hysteresis in early preconditioning cycles and repeatable behavior after 4 cycles, and nonlinear stiffening, particularly at CSF pressures 15 mmHg (Figure). Tangent moduli measured from the loading curve were 372 101, 1199 358, and 2050 379 kPa (mean SEM) at CSF pressures of 7, 15 and 30 mmHg, respectively. Flow rate measurements through the intact meninges at 30mmHg gave a permeability of 1.34 0.46 lmincm2mmHg (mean SEM). The ONS is a tough, strain-stiffening connective tissue that is surprisingly permeable. The latter observation suggests that there could be significant CSF drainage through the ONS into the orbit, likely important

  17. Optic Nerve Sheath Mechanics and Permeability in VIIP Syndrome

    Science.gov (United States)

    Raykin, Julia; Best, Lauren; Gleason, Rudy; Mulugeta, Lealem; Myers, Jerry; Nelson, Emily; Samuels, Brian C.; Ethier, C. R.

    2014-01-01

    Long-duration space flight carries the risk of developing Visual Impairment and Intracranial Pressure (VIIP) syndrome, a spectrum of ophthalmic changes including posterior globe flattening, choroidal folds, distension of the optic nerve sheath (ONS), optic nerve kinking and potentially permanent degradation of visual function. The slow onset of VIIP, its chronic nature, and certain clinical features strongly suggest that biomechanical factors acting on the ONS play a role in VIIP. Here we measure several relevant ONS properties needed to model VIIP biomechanics. The ONS (meninges) of fresh porcine eyes (n7) was reflected, the nerve proper was truncated near the sclera, and the meninges were repositioned to create a hollow cylinder of meningeal connective tissue attached to the posterior sclera. The distal end was cannulated, sealed, and pressure clamped (mimicking cerebrospinal fluid [CSF] pressure), while the eye was also cannulated for independent control of intraocular pressure (IOP). The meninges were inflated (CSF pressure cycling 7-50 mmHg) while ONS outer diameter was imaged. In another set of experiments (n4), fluid permeation rate across the meninges was recorded by observing the drainage of an elevated fluid reservoir (30 mmHg) connected to the meninges. The ONS showed behavior typical of soft tissues: viscoelasticity, with hysteresis in early preconditioning cycles and repeatable behavior after 4 cycles, and nonlinear stiffening, particularly at CSF pressures 15 mmHg (Figure). Tangent moduli measured from the loading curve were 372 101, 1199 358, and 2050 379 kPa (mean SEM) at CSF pressures of 7, 15 and 30 mmHg, respectively. Flow rate measurements through the intact meninges at 30mmHg gave a permeability of 1.34 0.46 lmincm2mmHg (mean SEM). The ONS is a tough, strain-stiffening connective tissue that is surprisingly permeable. The latter observation suggests that there could be significant CSF drainage through the ONS into the orbit, likely important

  18. Electron emission in a source-collector sheath system: A kinetic study

    Energy Technology Data Exchange (ETDEWEB)

    Rizopoulou, N., E-mail: nikoleta.rizopoulou06@imperial.ac.uk; Coppins, M.; Bacharis, M. [Blackett Laboratory, Imperial College, Prince Consort Road, London SW7 2BW (United Kingdom); Robinson, A. P. L. [Central Laser Facility, Rutherford-Appleton Laboratory, Chilton, Oxon OX11 0QX (United Kingdom)

    2014-10-15

    The classical source-collector sheath system describes a plasma that forms between a Maxwellian source and an absorbing wall. The plasma is assumed to be collisionless and without ionization. Two distinct areas are being formed: the collector sheath, an ion-rich region in contact with the absorbing boundary, and the source sheath, which is an electron-rich area near the Maxwellian source. In this work, we study a modified version of the classical source-collector sheath system, where the wall is no longer absorbing but emits electrons. As a result, we have two different types of collector sheath, one where a potential well is formed and one without a potential well. We examine the effect of electron emission for a range of conditions for the plasma and the emitted electrons. In the first part of this work, we study the problem analytically, and in the second, using our kinetic Vlasov code, Yggdrasil. The simulation results are in very good agreement with the predictions of our theoretical model.

  19. FUNCTION OF MALATDEHYDROGENASE COMPLEX OF MAIZE MESOPHYLL AND BUNDLE SHEATH CELLS UNDER SALT STRESS CONDITION

    Directory of Open Access Journals (Sweden)

    Еprintsev А.Т.

    2006-12-01

    Full Text Available Salt-induced changes in malatdehydrogenase system activity make the essential contribution to cell adaptation to stress condition. The enzyme systems of C4-plants are most interesting due to their ability for adaptation to environment conditions. The role of separate components of malatdehydrogenase complex of mesophyll and bundle sheath cells of corn in formation of adaptive reaction in stressful conditions is investigated in presented work.The activation of all enzymes of malatdehydrogenase system and the subsequent decrease in their activity was observed in mesophyll durring the first stage of adaptation to salt influence. In bundle sheath cells such parameters are differed from control less essentially. Fast accumulation of piruvate in cells and malate in both investigated tissues was induced. The further salinity led to falling of concentration this intermediate. The concentration of piruvate was below control level, and it was raised by the end of an exposition.The results show that sodium chloride causes induction of Krebs-cycle in mesophyll and bundle sheath cells of corn and intensification of Hatch-Slack cycle. The described differences in function malatdehydrogenase systems of mesophyll and bundle sheath cells of leaves of corn under salinity mainly consist of the activity of enzymes of a studied complex in bundle sheath cells is subject to the minimal changes in comparison with mesophyll. Role of this enzymesystem in mechanisms of adaptive reaction of various tissues of corn to salt stress is discussed.

  20. Sheathed electrical resistance heaters for nuclear or other specialized service - approved 1973

    International Nuclear Information System (INIS)

    Anon.

    1976-01-01

    This specification presents the requirements for cylindrical metal-sheathed, electrical resistance heaters with compacted mineral-oxide insulation for nuclear or other specialized service. The intended use of a sheathed heater in a specific nuclear or general application will require an evaluation by the purchaser of the compatibility of the heater assembly in the proposed application including the effects of the integrated proposed application including the effects of the integrated neutron flux, temperature, and atmosphere on the properties of the materials of construction. This specification does not include all possible specifications, standards, etc. for materials that may be used in sheathing, insulation, resistance wire, or conductors wire in nuclear environments. The requirements of this specification include only the austenitic stainless steels and nickel-based alloys for sheathing; magnesium oxide, aluminum oxide, beryllium oxide for insulation; and nickel-chromium or iron-chromium-aluminum heater elements with or without low-resistance connecting wires. The intent of this specification is to present the requirements for heaters capable of operating at sheath temperatures and heat fluxes that will limit the maximum internal heater-element temperature to 1050 0 C

  1. ELESTRES: performance of nuclear fuel, circumferential ridging, and multiaxial elastic-plastic stresses in sheaths

    International Nuclear Information System (INIS)

    Tayal, M.

    1986-10-01

    The finite element code ELESTRES models the two-dimensional axisymmetric behaviour of a CANDU fuel element during normal operation. The main focus of the code is to estimate temperatures, fission gas release, and axial variations of deformation/stresses in the pellet and in the sheath. Thus the code is able to predict details like stresses/strains at circumferential ridges. This paper describes the current version of ELESTRES. The emphasis is on a recent addition: multiaxial stresses in the sheath near circumferential ridges. For accuracy in the critical region, a fine mesh is used near the ridge. To keep computing costs low, a coarse mesh is used near the midplane of the pellet. Predictions of ELESTRES show good agreement with abouth 80 measurements of fission-gas-release. In this paper, we also present ELESTRES predictions of hoop strains in sheaths, for two irradiations: element ABS and bundle GB. For both irradiations, predictions, compare favourably with measurements. An illustrative example shows that near circumferential ridges, bending contributes to multiaxial stresses in the sheath. This can have a significant effect on sheath integrity, such as during stress-corrosion-cracking due to power-increases, or during corrosion-assisted-fatigue due to power cycling

  2. The effect of flexor sheath integrity on nutrient uptake by primate flexor tendons.

    Science.gov (United States)

    Peterson, W W; Manske, P R; Lesker, P A

    1986-05-01

    The effect of flexor sheath excision versus sheath incision and repair on the uptake of 3H-proline by profundus tendons in zone II was examined. Proline uptake was measured at 7 days in eight monkeys with intact flexor tendons (group I) and at either 3 or 7 days in eight monkeys with the tendons transected and repaired (group II). In both groups, the flexor sheaths of the digits of the right hand were excised, whereas those of the left hand were incised and repaired. For both the intact and the transected and repaired flexor tendons, it was found that 3H-proline uptake was not improved with sheath closure. The extracellular tissue fluid appeared to be capable of providing nutrients to the tendon in amounts equal to that of the synovial fluid. Therefore, closure of the sheath after primary flexor tendon repair does not appear to be necessary for tendon nutrition, according to the data obtained from experimental studies on the nonhuman primate.

  3. Effects of neutral gas collisions on the power transmission factor at the divertor sheath

    International Nuclear Information System (INIS)

    Futch, A.H.; Matthews, G.F.; Buchenauer, D.; Hill, D.N.; Jong, R.A.; Porter, G.D.

    1992-01-01

    We show that charge-exchange and other ion-neutral collision can reduce the power transmission factor of the plasma sheath, thereby lowering the ion impact energy and target plate sputtering. The power transmission factor relates the heat flux reaching the divertor target to the plasma density and temperature just in front of the surface: δ=Q surf /J ew k T e . Experimental data from the DIII-D tokamak suggests that δ could be as low as 2-3 near the region of peak divertor particle flux, instead of the 7-8 expected from usual sheath theory. Several effects combine to allow ion-neutral interactions to be important in the divertor plasma sheath. The shallow angle of incidence of the magnetic field (1-3deg in DIII-D) leads to the spatial extension of the sheath from approximately ρ i ∝1 mm normal to the plate to several centimeters along the field lines. Ionization reduces the sheath potential, and collisions reduce the ion impact energy. (orig.)

  4. Elongation growth of the leaf sheath base of Avena sativa seedlings: regulation by hormones and sucrose

    Science.gov (United States)

    Brock, T. G.; Kaufman, P. B.

    1991-01-01

    The leaf sheath base of the seedling of Avena sativa was characterized for growth response to hormones and sucrose. Six day old plants, raised under a 10:14 hr light:dark cycle, were excised at the coleoptilar node and 1 cm above the node for treatment. The growth of the leaf sheath base was promoted by gibberellic acid (GA3) and this response was dose dependent. The lag to response initiation was approximately 4 hr. Growth with or without GA3 (10 micromoles) was transient, diminishing appreciably after 48 hr. The addition of 10 mM sucrose greatly prolonged growth; the effect of GA3 and sucrose was additive. Neither indole-3-acetic acid (IAA) nor the cytokinin N6-benzyladenine (BA), alone or in combination, promoted the growth of leaf sheath bases. However, both significantly inhibited the action of GA3. The inhibitory effect of IAA was dose dependent and was not affected by the addition of BA or sucrose. These results indicate that the growth of leaf sheath bases of Avena sativa is promoted specifically by gibberellin, that this action depends on the availability of carbohydrates from outside of the leaf sheath base, and that the promotional effect of GA3 can be modified by either auxins or cytokinins.

  5. An integrative time-varying frequency detection and channel sounding method for dynamic plasma sheath

    Science.gov (United States)

    Shi, Lei; Yao, Bo; Zhao, Lei; Liu, Xiaotong; Yang, Min; Liu, Yanming

    2018-01-01

    The plasma sheath-surrounded hypersonic vehicle is a dynamic and time-varying medium and it is almost impossible to calculate time-varying physical parameters directly. The in-fight detection of the time-varying degree is important to understand the dynamic nature of the physical parameters and their effect on re-entry communication. In this paper, a constant envelope zero autocorrelation (CAZAC) sequence based on time-varying frequency detection and channel sounding method is proposed to detect the plasma sheath electronic density time-varying property and wireless channel characteristic. The proposed method utilizes the CAZAC sequence, which has excellent autocorrelation and spread gain characteristics, to realize dynamic time-varying detection/channel sounding under low signal-to-noise ratio in the plasma sheath environment. Theoretical simulation under a typical time-varying radio channel shows that the proposed method is capable of detecting time-variation frequency up to 200 kHz and can trace the channel amplitude and phase in the time domain well under -10 dB. Experimental results conducted in the RF modulation discharge plasma device verified the time variation detection ability in practical dynamic plasma sheath. Meanwhile, nonlinear phenomenon of dynamic plasma sheath on communication signal is observed thorough channel sounding result.

  6. A Rare Malignant Peripheral Nerve Sheath Tumor of the Maxilla Mimicking a Periapical Lesion

    Directory of Open Access Journals (Sweden)

    José Alcides Arruda

    2016-01-01

    Full Text Available Malignant peripheral nerve sheath tumor is a malignant neoplasm that is rarely found in the oral cavity. About 50% of this tumor occurs in patients with neurofibromatosis type I and comprises approximately 10% of all soft tissue sarcomas of head and neck region. Intraosseous malignant peripheral nerve sheath tumor of the maxilla is rare. This article is the first to address malignant peripheral nerve sheath tumor of the maxilla presenting as a periapical radiolucency on nonvital endodontically treated teeth in the English medical literature. Surgical approaches to malignant soft tissue tumor vary based on the extent of the disease, age of the patient, and pathological findings. A rare case of intraosseous malignant peripheral nerve sheath tumor is reported in a 16-year-old woman. The patient presented clinically with a pain involving the upper left incisors region and with defined unilocular periapical radiolucency lesion involved between the upper left incisors. An incisional biopsy was made. Histological and immunohistochemical examination were positive for S-100 protein and glial fibrillary acidic protein showed that the lesion was an intraosseous malignant peripheral nerve sheath tumor of the maxilla. Nine years after the surgery, no regional recurrence was observed.

  7. Comparison of Outside Versus Inside Brachial Plexus Sheath Injection for Ultrasound-Guided Interscalene Nerve Blocks.

    Science.gov (United States)

    Maga, Joni; Missair, Andres; Visan, Alex; Kaplan, Lee; Gutierrez, Juan F; Jain, Annika R; Gebhard, Ralf E

    2016-02-01

    Ultrasound-guided interscalene brachial plexus blocks are commonly used to provide anesthesia for the shoulder and proximal upper extremity. Some reviews identify a sheath that envelops the brachial plexus as a potential tissue plane target, and current editorials in the literature highlight the need to establish precise and reproducible injection targets under ultrasound guidance. We hypothesize that an injection of a local anesthetic inside the brachial plexus sheath during ultrasound-guided interscalene nerve blocks will result in enhanced procedure success and provide a consistent tissue plane target for this approach with a reproducible and characteristic local anesthetic spread pattern. Sixty patients scheduled for shoulder surgery with a preoperative interscalene block for postoperative pain management were enrolled in this prospective randomized observer-blinded study. Each patient was randomly assigned to receive a single-shot interscalene block either inside or outside the brachial plexus sheath. The rate of complete motor and sensory blocks of the axillary nerve territory 10 minutes after local anesthetic injection for the inside group was 70% versus 37% for the outside group (P complete sensory blockade. The incidence rates of transient paresthesia during needle passage were 6.7% for the outside group and 96.7% for the inside group (P randomized trial did not find any advantages to performing an interscalene block inside the brachial plexus sheath. There was a higher incidence of transient paresthesia when injections were performed inside compared to outside the sheath. © 2016 by the American Institute of Ultrasound in Medicine.

  8. Structural analysis of sheath folds in the Sylacauga Marble Group, Talladega slate belt, southern Appalachians

    Science.gov (United States)

    Mies, J.W.

    1993-01-01

    Remnant blocks of marble from the Moretti-Harrah dimension-stone quarry provide excellent exposure of meter-scale sheath folds. Tubular structures with elliptical cross-sections (4 ???Ryz ??? 5) are the most common expression of the folds. The tubes are elongate subparallel to stretching lineation and are defined by centimeter-scale layers of schist. Eccentrically nested elliptical patterns and opposing asymmetry of folds ('S' and 'Z') are consistent with the sheath-fold interpretation. Sheath folds are locally numerous in the Moretti-Harrah quarry but are not widely distributed in the Sylacauga Marble Group; reconnaissance in neighboring quarries provided no additional observations. The presence of sheath folds in part of the Talladega slate belt indicates a local history of plastic, non-coaxial deformation. Such a history of deformation is substantiated by petrographic study of an extracted hinge from the Moretti-Harrah quarry. The sheath folds are modeled as due to passive amplification of initial structures during simple shear, using both analytic geometry and graphic simulation. As indicated by these models, relatively large shear strains (y ??? 9) and longitudinal initial structures are required. The shear strain presumably relates to NW-directed displacement of overlying crystalline rocks during late Paleozoic orogeny. ?? 1993.

  9. Estimation of sheath potentials in front of ASDEX upgrade ICRF antenna with SSWICH asymptotic code

    Energy Technology Data Exchange (ETDEWEB)

    Křivská, A., E-mail: alena.krivska@rma.ac.be [LPP-ERM/KMS, Royal Military Academy, 30 Avenue de la Renaissance B-1000, Brussels (Belgium); Bobkov, V.; Jacquot, J.; Ochoukov, R. [Max-Planck-Institut für Plasmaphysik, D-85748 Garching (Germany); Colas, L. [CEA, IRFM, F-13108 Saint-Paul-Lez-Durance (France); Milanesio, D. [Politecnico di Torino, Corso Duca degli Abruzzi 24, I-10129 Torino (Italy)

    2015-12-10

    Multi-megawatt Ion Cyclotron Range of Frequencies (ICRF) heating became problematic in ASDEX Upgrade (AUG) tokamak after coating of ICRF antenna limiters and other plasma facing components by tungsten. Strong impurity influx was indeed produced at levels of injected power markedly lower than in the previous experiments. It is assumed that the impurity production is mainly driven by parallel component of Radio-Frequency (RF) antenna electric near-field E// that is rectified in sheaths. In this contribution we estimate poloidal distribution of sheath Direct Current (DC) potential in front of the ICRF antenna and simulate its relative variations over the parametric scans performed during experiments, trying to reproduce some of the experimental observations. In addition, relative comparison between two types of AUG ICRF antenna configurations, used for experiments in 2014, has been performed. For this purpose we use the Torino Polytechnic Ion Cyclotron Antenna (TOPICA) code and asymptotic version of the Self-consistent Sheaths and Waves for Ion Cyclotron Heating (SSWICH) code. Further, we investigate correlation between amplitudes of the calculated oscillating sheath voltages and the E// fields computed at the lateral side of the antenna box, in relation with a heuristic antenna design strategy at IPP Garching to mitigate RF sheaths.

  10. Particulates from Hydrophilic-Coated Guiding Sheaths Embolize to the Brain

    Science.gov (United States)

    Stanley, James R.L.; Tzafriri, Abraham R.; Regan, Kathryn; LaRochelle, Alan; Wong, Gee; Zani, Brett G.; Markham, Peter M.; Bailey, Lynn; Spognardi, Anna; Kopia, Gregory A.; Edelman, Elazer R.

    2015-01-01

    Aims We sought to evaluate the incidence of embolic material in porcine brain following vascular interventions using hydrophilic-coated sheaths. Methods and results A new self-expanding stent and delivery system (SDS) were deployed through a hydrophilic-coated (Cook® Flexor Ansel) Guiding Sheath into iliac and/or carotid arteries of 23 anesthetized Yucatan miniswine. Animals were euthanized at 3, 30, 90 and 180 days and brains were removed for histological analysis. In an additional single control animal, the guiding sheath was advanced but no SDS was deployed. Advancement of the coated guiding sheath with or without the SDS was associated with frequent foreign material in the arterioles of the brain. The embolic material was amorphous, non-refractile, non-crystalline, and non-birefringent and typically lightly basophilic with a slight stippled appearance on hematoxylin and eosin (H&E) stain. Material was observed at all time points involving 54% of all study animals (ie, test and control) and in vitro after incubation in 0.9% saline. Conclusions The hydrophilic coating on a clinically used guiding sheath readily avulses and embolizes to the brain during deployment in a porcine model. Further documentation of this effect and monitoring in clinical scenarios is warranted. PMID:25735934

  11. Slender transradial iliac artery stenting using a 4.5 French guiding sheath.

    Science.gov (United States)

    Shinozaki, Norihiko; Minowa, Takashi; Murakami, Tsutomu; Ohno, Yohei; Nakano, Masataka; Fujii, Toshiharu; Nakazawa, Gaku; Yoshimachi, Fuminobu; Ikari, Yuji

    2018-01-05

    We previously reported safety and usefulness of transradial iliac artery stenting using 6 Fr guiding sheath. However, radial artery occlusion was a major limitation of this procedure. We analyzed the safety and utility of slender transradial iliac artery stenting using a 4.5 Fr guiding sheath to prevent radial artery occlusion. We performed transradial iliac artery stenting in left radial artery, using a 4.5 Fr sheath incorporating a shaft length of 110 cm, for 34 lesions in 29 patients. Transradial intervention was attempted at the discretion of the operator. Clinical data were analyzed retrospectively. Cases with scheduled multiple sheath insertions for a bidirectional approach were excluded. Twenty-three (79.3%) patients were male. Diabetes mellitus, hypertension, dyslipidemia, and smoking habit were present in 11 (37.9%), 27 (93.1%), 19 (65.5%), and 24 (82.8%) patients, respectively. Nine lesions (26.5%) were diagnosed as chronic total occlusion. All lesions were successfully treated using a total of 40 stents incorporating a 4.5 Fr radial access system. Ankle-brachial index (ABI) significantly improved from 0.68 ± 0.15 to 0.99 ± 0.17 (p guiding sheath is safe, feasible, and less invasive, and shows no incidence of radial artery occlusion, in carefully selected patient populations.

  12. Twisting method for reducing friction during insertion of a sheath introducer and a sheathless guiding catheter.

    Science.gov (United States)

    Takagawa, Yoshitoki; Furukawa, Tetsuaki

    2018-01-01

    A sheathless system that inserts a catheter directly into the artery can reduce puncture site-related complications through a 2-Fr reduction of the outer diameter. However, the gap between the dilator and the guiding catheter of the sheathless system is larger than the gap between the dilator and sheath of the introducer system, resulting in stronger insertion resistance. A twisting method with rapid alternating rotation of a device to the left and right during insertion can reduce the insertion resistance. This method can be effective with the sheathless system which has a larger gap. To examine the effect of size reduction on the sheathless system and the effect of insertion resistance reduction using the twisting method, we developed an insertion simulator and compared insertion resistance to a 5-Fr sheath introducer and a 5-Fr sheathless system, with and without the twisting method. The insertion simulator pushed a sheath introducer or a sheathless system toward a mock artery consisted with a 5-mm urethane and a 1-mm rubber sheet by an electrical motor with or without twisting motion generated by a crank shaft. Insertion resistance during the penetration was measured by a tension meter. The insertion resistance was less with the 5-Fr sheathless system than with the 5-Fr sheath introducer. The resistance reduced further with use of twisting for both the sheathed and sheathless catheters. In conclusion, the experiment suggests the benefits of twisting insertion of a sheathless guiding catheter for reduction of puncture site-related complications.

  13. Particulates from hydrophilic-coated guiding sheaths embolise to the brain.

    Science.gov (United States)

    Stanley, James R L; Tzafriri, Abraham R; Regan, Kathryn; LaRochelle, Alan; Wong, Gee; Zani, Brett G; Markham, Peter M; Bailey, Lynn; Spognardi, Anna; Kopia, Gregory A; Edelman, Elazer R

    2016-03-01

    We sought to evaluate the incidence of embolic material in porcine brains following vascular interventions using hydrophilic-coated sheaths. A new self-expanding stent and delivery system (SDS) was deployed through a hydrophilic-coated (Flexor Ansel; Cook Medical, Bloomington, IN, USA) guiding sheath into the iliac and/or carotid arteries of 23 anaesthetised Yucatan mini swine. The animals were euthanised at three, 30, 90 and 180 days and their brains were removed for histological analysis. In an additional single control animal, the guiding sheath was advanced but no SDS was deployed. Advancement of the coated guiding sheath with or without the SDS was associated with frequent foreign material in the arterioles of the brain. The embolic material was amorphous, non-refractile, non-crystalline, non-birefringent and typically lightly basophilic with a slightly stippled appearance on haematoxylin and eosin (H&E) stain. Material was observed at all time points involving 54% of all study animals (i.e., test and control) and in vitro after incubation in 0.9% saline. The hydrophilic coating on a clinically used guiding sheath readily avulses and embolises to the brain during deployment in a porcine model. Further documentation of this effect and monitoring in clinical scenarios are warranted.

  14. High power switching and other high power devices

    Science.gov (United States)

    Gundersen, Martin

    1992-09-01

    High power thyratrons and devices such as high power microwave sources have cathode-related performance limits. Research is described of a simple, robust 'super-emissive' cathode that produces greater than 10,000 A/sq cm from a macroscopic area (approx. 1 sq cm), and operates with a low pressure (approx. 0.1 torr), spatially uniform glow plasma (density greater than 1015 cu cm). The cathode also can operate as a hollow cathode, and is at the heart of the operation of the pseudospark and back-lighted thyratron. The physics of this hollow and super-emissive cathode is very rich. The hollow cathode geometry traps electrons in the hollow cathode backspace. The lifetime of these electrons enables them to ionize a spatially homogeneous high density glow, and this hollow cathode mode of operation is responsible for certain types of electron and ion beam behavior. A plasma cathode sheath that is formed during this phase leads to super-emissive behavior, which is responsible for high current emission. Super-emissive cathode thyratron-type switches (with higher peak current, voltage, di/dt) being developed for pulsed power switching of lasers, accelerators, high current and high coulomb transfer, Marx bank operation, transfer of technology to commercial applications, high current electron beams, and millimeter wave generation (1 to 100 GHz) are described.

  15. Safe LPV Controller Switching

    DEFF Research Database (Denmark)

    Trangbæk, K

    2011-01-01

    Before switching to a new controller it is crucial to assure that the new closed loop will be stable. In this paper it is demonstrated how stability can be checked with limited measurement data available from the current closed loop. The paper extends an existing method to linear parameter varying...... plants and controllers. Rather than relying on frequency domain methods as done in the LTI case, it is shown how to use standard LPV system identification methods. It is furthermore shown how to include model uncertainty to robustify the results. By appropriate filtering, it is only necessary to evaluate...

  16. Safe LPV Controller Switching

    DEFF Research Database (Denmark)

    Trangbæk, K

    2010-01-01

    Before switching to a new controller it is crucial to assure that the new closed loop will be stable. In this paper it is demonstrated how stability can be checked with limited measurement data available from the current closed loop. The paper extends an existing method to linear parameter varying...... plants and controllers. Rather than relying on frequency domain methods as done in the LTI case, it is shown how to use standard LPV system identification methods. By identifying a filtered closed-loop operator rather than directly identifying the plant, more reliable results are obtained....

  17. Numerical simulation and analysis of electromagnetic-wave absorption of a plasma slab created by a direct-current discharge with gridded anode

    Science.gov (United States)

    Yuan, Chengxun; Tian, Ruihuan; Eliseev, S. I.; Bekasov, V. S.; Bogdanov, E. A.; Kudryavtsev, A. A.; Zhou, Zhongxiang

    2018-03-01

    In this paper, we present investigation of a direct-current discharge with a gridded anode from the point of view of using it as a means of creating plasma coating that could efficiently absorb incident electromagnetic (EM) waves. A single discharge cell consists of two parallel plates, one of which (anode) is gridded. Electrons emitted from the cathode surface are accelerated in the short interelectrode gap and are injected into the post-anode space, where they lose acquired energy on ionization and create plasma. Numerical simulations were used to investigate the discharge structure and obtain spatial distributions of plasma density in the post-anode space. The numerical model of the discharge was based on a simple hybrid approach which takes into account non-local ionization by fast electrons streaming from the cathode sheath. Specially formulated transparency boundary conditions allowed performing simulations in 1D. Simulations were carried out in air at pressures of 10 Torr and higher. Analysis of the discharge structure and discharge formation is presented. It is shown that using cathode materials with lower secondary emission coefficients can allow increasing the thickness of plasma slabs for the same discharge current, which can potentially enhance EM wave absorption. Spatial distributions of electron density obtained during simulations were used to calculate attenuation of an incident EM wave propagating perpendicularly to the plasma slab boundary. It is shown that plasma created by means of a DC discharge with a gridded anode can efficiently absorb EM waves in the low frequency range (6-40 GHz). Increasing gas pressure results in a broader range of wave frequencies (up to 500 GHz) where a considerable attenuation is observed.

  18. The normal tendon sheath of the second to fifth fingers as seen on oblique views

    International Nuclear Information System (INIS)

    Fischer, E.

    1984-01-01

    Oblique views of the fingers, using a low kilovolt technique, show a portion of the tendon sheaths which can be regarded as representative of the entire sheath. Because of the varying obliquity of each finger, this proportion differs in the fingers. With increasing age the projected portion of the sheath becomes smaller because it is covered by increasing bone formation in the insertion of the tendon sheat. Normal values have been obtained for adults according to their decades; from these, quite minor degrees of tendon sheat thickening can be determined. In camptodactyly of the fifth finger, which is not uncommon, the tendon sheat may be widened in the absence of a tenosynovitis. (orig.) [de

  19. A matching approach to communicate through the plasma sheath surrounding a hypersonic vehicle

    International Nuclear Information System (INIS)

    Gao, Xiaotian; Jiang, Binhao

    2015-01-01

    In order to overcome the communication blackout problem suffered by hypersonic vehicles, a matching approach has been proposed for the first time in this paper. It utilizes a double-positive (DPS) material layer surrounding a hypersonic vehicle antenna to match with the plasma sheath enclosing the vehicle. Analytical analysis and numerical results indicate a resonance between the matched layer and the plasma sheath will be formed to mitigate the blackout problem in some conditions. The calculated results present a perfect radiated performance of the antenna, when the match is exactly built between these two layers. The effects of the parameters of the plasma sheath have been researched by numerical methods. Based on these results, the proposed approach is easier to realize and more flexible to the varying radiated conditions in hypersonic flight comparing with other methods

  20. Observation of Self-Sustaining Relativistic Ionization Wave Launched by a Sheath Field

    Science.gov (United States)

    McCormick, M.; Arefiev, A. V.; Quevedo, H. J.; Bengtson, R. D.; Ditmire, T.

    2014-01-01

    We present experimental evidence supported by simulations of a relativistic ionization wave launched into a surrounding gas by the sheath field of a plasma filament with high energy electrons. Such a filament is created by irradiating a clustering gas jet with a short pulse laser (115 fs) at a peak intensity of 5×1017 W/cm2. We observe an ionization wave propagating radially through the gas for about 2 ps at 0.2-0.5 c after the laser has passed, doubling the initial radius of the filament. The gas is ionized by the sheath field, while the longevity of the wave is explained by a moving field structure that traps the high energy electrons near the boundary, maintaining a strong sheath field despite the significant expansion of the plasma.

  1. Online Fault Location on AC Cables in Underground Transmission Systems using Sheath Currents

    DEFF Research Database (Denmark)

    Jensen, Christian Flytkjær; Nanayakkarab, Kasun; Rajapakse, Athula

    2014-01-01

    This paper studies online travelling wave methods for fault location on a crossbonded cable system using sheath currents. During the construction of the electrical connection to the 400 MW off shore wind farm Anholt, it was possible to perform measurements on a 38.4 km crossbonded cable system....... At 31.4 km, all cables were accessible which made it possible to apply a fault using an arc free breaker and measure the travelling waves at each end of the cable. On a crossbonded cable system, the sheaths are short circuited and grounded at both ends. This makes possible the use of low voltage...... Rogowski coils if the sheath currents contain the necessary information for accurate fault location. In this paper, this is examined by analysis of field measurements and through a study of simulations. The wavelet transform and a visual inspection method are used and the accuracy is compared. Field...

  2. Physical properties of magnetized electrostatic sheath in presence of dust particles and monoenergetic electrons

    Science.gov (United States)

    Chekour, S.; Tahraoui, A.; Fouial, N.

    2018-01-01

    In this work, we have studied the physical properties of magnetized electrostatic sheaths in presence of dust grains and monoenergetic electrons. For this, we have established a three dimensional and stationary model. The electrons and negative ions are considered in thermodynamic equilibrium. However, the positive ions, the monoenergetic electrons and the dust grains are described by the cold fluid equations. Furthermore, the dust charge is described by the orbit motion limited model (OML). The numerical results show that the presence of a magnetic field reduces the sheath thickness. On the other hand, the presence of monoenergetic electrons changes the behavior of the electrostatic sheath physical parameters. The effects of the other parameters are also analyzed and discussed.

  3. STRETCHY ELECTRONICS. Hierarchically buckled sheath-core fibers for superelastic electronics, sensors, and muscles.

    Science.gov (United States)

    Liu, Z F; Fang, S; Moura, F A; Ding, J N; Jiang, N; Di, J; Zhang, M; Lepró, X; Galvão, D S; Haines, C S; Yuan, N Y; Yin, S G; Lee, D W; Wang, R; Wang, H Y; Lv, W; Dong, C; Zhang, R C; Chen, M J; Yin, Q; Chong, Y T; Zhang, R; Wang, X; Lima, M D; Ovalle-Robles, R; Qian, D; Lu, H; Baughman, R H

    2015-07-24

    Superelastic conducting fibers with improved properties and functionalities are needed for diverse applications. Here we report the fabrication of highly stretchable (up to 1320%) sheath-core conducting fibers created by wrapping carbon nanotube sheets oriented in the fiber direction on stretched rubber fiber cores. The resulting structure exhibited distinct short- and long-period sheath buckling that occurred reversibly out of phase in the axial and belt directions, enabling a resistance change of less than 5% for a 1000% stretch. By including other rubber and carbon nanotube sheath layers, we demonstrated strain sensors generating an 860% capacitance change and electrically powered torsional muscles operating reversibly by a coupled tension-to-torsion actuation mechanism. Using theory, we quantitatively explain the complementary effects of an increase in muscle length and a large positive Poisson's ratio on torsional actuation and electronic properties. Copyright © 2015, American Association for the Advancement of Science.

  4. Neuromorphic atomic switch networks.

    Directory of Open Access Journals (Sweden)

    Audrius V Avizienis

    Full Text Available Efforts to emulate the formidable information processing capabilities of the brain through neuromorphic engineering have been bolstered by recent progress in the fabrication of nonlinear, nanoscale circuit elements that exhibit synapse-like operational characteristics. However, conventional fabrication techniques are unable to efficiently generate structures with the highly complex interconnectivity found in biological neuronal networks. Here we demonstrate the physical realization of a self-assembled neuromorphic device which implements basic concepts of systems neuroscience through a hardware-based platform comprised of over a billion interconnected atomic-switch inorganic synapses embedded in a complex network of silver nanowires. Observations of network activation and passive harmonic generation demonstrate a collective response to input stimulus in agreement with recent theoretical predictions. Further, emergent behaviors unique to the complex network of atomic switches and akin to brain function are observed, namely spatially distributed memory, recurrent dynamics and the activation of feedforward subnetworks. These devices display the functional characteristics required for implementing unconventional, biologically and neurally inspired computational methodologies in a synthetic experimental system.

  5. Modeling of rf MEMS switches

    Science.gov (United States)

    Robertson, Barbara; Ho, Fat D.; Hudson, Tracy D.

    2001-10-01

    The microelectromechanical system (MEMS) switch offers many benefits in radio frequency (RF) applications. These benefits include low insertion loss, high quality factor (Q), low power, RF isolation, and low cost. The ability to manufacture mechanical switches on a chip with electronics can lead to higher functionality, such as single-chip arrays, and smart switches. The MEMS switch is also used as a building block in devices such as phase shifters, filters, and switchable antenna elements. The MEMS designer needs models of these basic elements in order to incorporate them into their applications. The objective of this effort is to develop lumped element models for MEMS RF switches, which are incorporated into a CAD software. Tanner Research Inc.'s Electronic Design Automation (EDA) software is being used to develop a suite of mixed-signal RF switch models. The suite will include switches made from cantilever beams and fixed-fixed beams. The switches may be actuated by electrostatic, piezoelectric or electromagnetic forces. The effort presented in this paper concentrates on switches actuated by electrostatic forces. The lumped element models use a current-force electrical-mechanical analogy. Finite element modeling and device testing will be used to verify the Tanner models. The effects of materials, geometries, temperature, fringing fields, and mounting geometries are considered.

  6. Software Switching for Data Acquisition

    CERN Multimedia

    CERN. Geneva; Malone, David

    2016-01-01

    In this talk we discuss the feasibility of replacing telecom-class routers with a topology of commodity servers acting as software switches in data acquisition. We extend the popular software switch, Open vSwitch, with a dedicated, throughput-oriented buffering mechanism. We compare the performance under heavy many-to-one congestion to typical Ethernet switches and evaluate the scalability when building larger topologies, exploiting the integration with software-defined networking technologies. Please note that David Malone will speak on behalf of Grzegorz Jereczek.

  7. Recent developments in switching theory

    CERN Document Server

    Mukhopadhyay, Amar

    2013-01-01

    Electrical Science Series: Recent Developments in Switching Theory covers the progress in the study of the switching theory. The book discusses the simplified proof of Post's theorem on completeness of logic primitives; the role of feedback in combinational switching circuits; and the systematic procedure for the design of Lupanov decoding networks. The text also describes the classical results on counting theorems and their application to the classification of switching functions under different notions of equivalence, including linear and affine equivalences. The development of abstract har

  8. Application of Spray Foam Insulation Under Plywood and Oriented Strand Board Roof Sheathing

    Energy Technology Data Exchange (ETDEWEB)

    Grin, A.; Smegal, J.; Lstiburek, J.

    2013-10-01

    Unvented roof strategies with open cell and closed cell spray polyurethane foam insulation sprayed to the underside of roof sheathing have been used since the mid-1990's to provide durable and efficient building enclosures. However, there have been isolated moisture related incidents reported anecdotally that raise potential concerns about the overall hygrothermal performance of these systems. The incidents related to rainwater leakage and condensation concerns. Condensation concerns have been extensively studied by others and are not further discussed in this report. This project involved hygrothermal modeling of a range of rainwater leakage and field evaluations of in-service residential roofs using spray foam insulation. All of the roof assemblies modeled exhibited drying capacity to handle minor rainwater leakage. All field evaluation locations of in-service residential roofs had moisture contents well within the safe range for wood-based sheathing. Explorations of eleven in-service roof systems were completed. The exploration involved taking a sample of spray foam from the underside of the roof sheathing, exposing the sheathing, then taking a moisture content reading. All locations had moisture contents well within the safe range for wood-based sheathing. One full-roof failure was reviewed, as an industry partner was involved with replacing structurally failed roof sheathing. In this case the manufacturer's investigation report concluded that the spray foam was installed on wet OSB based on the observation that the spray foam did not adhere well to the substrate and the pore structure of the closed cell spray foam at the ccSPF/OSB interface was indicative of a wet substrate.

  9. Sheath parameters for non-Debye plasmas: Simulations and arc damage

    Directory of Open Access Journals (Sweden)

    I. V. Morozov

    2012-05-01

    Full Text Available This paper describes the surface environment of the dense plasma arcs that damage rf accelerators, tokamaks, and other high gradient structures. We simulate the dense, nonideal plasma sheath near a metallic surface using molecular dynamics (MD to evaluate sheaths in the non-Debye region for high density, low temperature plasmas. We use direct two-component MD simulations where the interactions between all electrons and ions are computed explicitly. We find that the non-Debye sheath can be extrapolated from the Debye sheath parameters with small corrections. We find that these parameters are roughly consistent with previous particle-in-cell code estimates, pointing to densities in the range 10^{24}–10^{25}  m^{-3}. The high surface fields implied by these results could produce field emission that would short the sheath and cause an instability in the time evolution of the arc, and this mechanism could limit the maximum density and surface field in the arc. These results also provide a way of understanding how the properties of the arc depend on the properties (sublimation energy, for example of the metal. Using these results, and equating surface tension and plasma pressure, it is possible to infer a range of plasma densities and sheath potentials from scanning electron microscope images of arc damage. We find that the high density plasma these results imply and the level of plasma pressure they would produce is consistent with arc damage on a scale 100 nm or less, in examples where the liquid metal would cool before this structure would be lost. We find that the submicron component of arc damage, the burn voltage, and fluctuations in the visible light production of arcs may be the most direct indicators of the parameters of the dense plasma arc, and the most useful diagnostics of the mechanisms limiting gradients in accelerators.

  10. Spontaneous rectus sheath hematomas in dengue hemorrhagic fever: A case report.

    Science.gov (United States)

    Nelwan, Erni Juwita; Angelina, Frida; Adiwinata, Randy; Matondang, Sahat; Andriono, Prasetyo

    2017-01-01

    Muscle hematomas are rare complications in dengue hemorrhagic fever (DHF). We report a case of 58-year-old-female admitted with dengue fever who developed spontaneous rectus sheath hematoma complicating DHF. She presented with progressive thrombocytopenia with platelet count reaching 13000/μL at its lowest point. There was evidence of plasma leakage and persistent cough during the course of illness. During the recovery phase, she reported severe abdominal pain and developed hematoma in the right rectus sheath, which was confirmed by abdominal computed-tomography scan and serial magnetic resonance imaging. This complication during convalescent period of DHF needs to be recognized so it can be managed appropriately.

  11. Synthesis of sheath voltage drops in asymmetric radio-frequency discharges

    International Nuclear Information System (INIS)

    Yonemura, Shigeru; Nanbu, Kenichi; Iwata, Naoaki

    2004-01-01

    A sheath voltage drop in asymmetric discharges is one of the most important parameters of radio-frequency capacitively coupled plasmas because it determines the kinetic energy of the ions incident on the target or substrate. In this study, we developed a numerical simulation code to estimate the sheath voltage drops and, consequently, the self-bias voltage. We roughly approximated general asymmetric rf discharges to one-dimensional spherical ones. The results obtained by using our simulation code are consistent with measurements and Lieberman's theory

  12. Three-dimensional Doppler ultrasound findings in healthy wrist and finger tendon sheaths

    DEFF Research Database (Denmark)

    Ammitzboll-Danielsen, Mads; Janta, Iustina; Torp-Pedersen, Søren

    2016-01-01

    interpretation of Doppler signals when diagnosing tenosynovitis. Method Forty healthy participants (20 women and 20 men age 23-67 years) without prior history of arthritis, tendon diseases or present pain in their hands were included. Twenty participants had 3D Doppler US of the second and third finger...... participant. No significant difference in feeding vessels was seen between the radial and carpal level in the wrist (p = 0.06) or between the second and third flexor tendon sheath (p = 0.84). Conclusion Doppler findings in or in close proximity to the tendon sheaths were common in wrists and fingers...

  13. Optic nerve sheath diameter: A novel way to monitor the brain

    Directory of Open Access Journals (Sweden)

    Seelora Sahu

    2017-01-01

    Full Text Available Measurement and monitoring of intracranial pressure is pivotal in management of brain injured patients. As a rapid and easily done bed side measurement, ultrasonography of the optic nerve sheath diameter presents itself as a possible replacement of the conventional invasive methods of intracranial pressure management. In this review we go through the evolution of optic nerve sheath diameter measurement as a novel marker of predicting raised intracranial pressure, the modalities by which it can be measured as well as its correlation with the invasive methods of intracranial pressure monitoring.

  14. Transparent Aluminum Oxide Films by Edge Anodization

    Science.gov (United States)

    Stott, Jonathan; Greenwood, Thomas; Winn, David

    In this paper we present our recent work on manufacturing thin (3 - 5 μm) films of porous aluminum(III) oxide [PAO] using a novel edge-anodization technique. With this modified anodization process, we are able to create transparent PAO films on top of insulating substrates such as glass or plastic. By controlling the processing parameters, the index of refraction of PAO films can be engineered to match the substrate, which gives us a durable reflection-free and scratch-resistant coating over conventional optics or LCD displays. Eventually we hope to create ordered porous aluminum oxide cladding around an optical fiber core, which could have a number of interesting optical properties if the pore spacing can be matched to the wavelength of light in the fiber. This work was funded by Fairfield University startup funding.

  15. Fuel cell anode configuration for CO tolerance

    Science.gov (United States)

    Uribe, Francisco A.; Zawodzinski, Thomas A.

    2004-11-16

    A polymer electrolyte fuel cell (PEFC) is designed to operate on a reformate fuel stream containing oxygen and diluted hydrogen fuel with CO impurities. A polymer electrolyte membrane has an electrocatalytic surface formed from an electrocatalyst mixed with the polymer and bonded on an anode side of the membrane. An anode backing is formed of a porous electrically conductive material and has a first surface abutting the electrocatalytic surface and a second surface facing away from the membrane. The second surface has an oxidation catalyst layer effective to catalyze the oxidation of CO by oxygen present in the fuel stream where at least the layer of oxidation catalyst is formed of a non-precious metal oxidation catalyst selected from the group consisting of Cu, Fe, Co, Tb, W, Mo, Sn, and oxides thereof, and other metals having at least two low oxidation states.

  16. Phenotypic switching in bacteria

    Science.gov (United States)

    Merrin, Jack

    Living matter is a non-equilibrium system in which many components work in parallel to perpetuate themselves through a fluctuating environment. Physiological states or functionalities revealed by a particular environment are called phenotypes. Transitions between phenotypes may occur either spontaneously or via interaction with the environment. Even in the same environment, genetically identical bacteria can exhibit different phenotypes of a continuous or discrete nature. In this thesis, we pursued three lines of investigation into discrete phenotypic heterogeneity in bacterial populations: the quantitative characterization of the so-called bacterial persistence, a theoretical model of phenotypic switching based on those measurements, and the design of artificial genetic networks which implement this model. Persistence is the phenotype of a subpopulation of bacteria with a reduced sensitivity to antibiotics. We developed a microfluidic apparatus, which allowed us to monitor the growth rates of individual cells while applying repeated cycles of antibiotic treatments. We were able to identify distinct phenotypes (normal and persistent) and characterize the stochastic transitions between them. We also found that phenotypic heterogeneity was present prior to any environmental cue such as antibiotic exposure. Motivated by the experiments with persisters, we formulated a theoretical model describing the dynamic behavior of several discrete phenotypes in a periodically varying environment. This theoretical framework allowed us to quantitatively predict the fitness of dynamic populations and to compare survival strategies according to environmental time-symmetries. These calculations suggested that persistence is a strategy used by bacterial populations to adapt to fluctuating environments. Knowledge of the phenotypic transition rates for persistence may provide statistical information about the typical environments of bacteria. We also describe a design of artificial

  17. Spinal Anodes for Lithium-Ion Batteries

    CSIR Research Space (South Africa)

    Ferg, E

    1994-11-01

    Full Text Available Anodes of Li4Mn5O12, Li4Ti5O12, and Li2Mn4O9 with a spinel-type structure have been evaluated in room-temperature lithium cells. The cathodes that were selected for this study were the stabilized spinels, Li1.03Mn1.97O4 and LiZn0.025Mn1.95O4...

  18. High performance anode for advanced Li batteries

    Energy Technology Data Exchange (ETDEWEB)

    Lake, Carla [Applied Sciences, Inc., Cedarville, OH (United States)

    2015-11-02

    The overall objective of this Phase I SBIR effort was to advance the manufacturing technology for ASI’s Si-CNF high-performance anode by creating a framework for large volume production and utilization of low-cost Si-coated carbon nanofibers (Si-CNF) for the battery industry. This project explores the use of nano-structured silicon which is deposited on a nano-scale carbon filament to achieve the benefits of high cycle life and high charge capacity without the consequent fading of, or failure in the capacity resulting from stress-induced fracturing of the Si particles and de-coupling from the electrode. ASI’s patented coating process distinguishes itself from others, in that it is highly reproducible, readily scalable and results in a Si-CNF composite structure containing 25-30% silicon, with a compositionally graded interface at the Si-CNF interface that significantly improve cycling stability and enhances adhesion of silicon to the carbon fiber support. In Phase I, the team demonstrated the production of the Si-CNF anode material can successfully be transitioned from a static bench-scale reactor into a fluidized bed reactor. In addition, ASI made significant progress in the development of low cost, quick testing methods which can be performed on silicon coated CNFs as a means of quality control. To date, weight change, density, and cycling performance were the key metrics used to validate the high performance anode material. Under this effort, ASI made strides to establish a quality control protocol for the large volume production of Si-CNFs and has identified several key technical thrusts for future work. Using the results of this Phase I effort as a foundation, ASI has defined a path forward to commercialize and deliver high volume and low-cost production of SI-CNF material for anodes in Li-ion batteries.

  19. Hybrid switch for resonant power converters

    Science.gov (United States)

    Lai, Jih-Sheng; Yu, Wensong

    2014-09-09

    A hybrid switch comprising two semiconductor switches connected in parallel but having different voltage drop characteristics as a function of current facilitates attainment of zero voltage switching and reduces conduction losses to complement reduction of switching losses achieved through zero voltage switching in power converters such as high-current inverters.

  20. Improvement in direct methanol fuel cell performance by treating the anode at high anodic potential

    Science.gov (United States)

    Joghee, Prabhuram; Pylypenko, Svitlana; Wood, Kevin; Corpuz, April; Bender, Guido; Dinh, Huyen N.; O'Hayre, Ryan

    2014-01-01

    This work investigates the effect of a high anodic potential treatment protocol on the performance of a direct methanol fuel cell (DMFC). DMFC membrane electrode assemblies (MEAs) with PtRu/C (Hi-spec 5000) anode catalyst are subjected to anodic treatment (AT) at 0.8 V vs. DHE using potentiostatic method. Despite causing a slight decrease in the electrochemical surface area (ECSA) of the anode, associated with ruthenium dissolution, AT results in significant improvement in DMFC performance in the ohmic and mass transfer regions and increases the maximum power density by ∼15%. Furthermore, AT improves the long-term DMFC stability by reducing the degradation of the anode catalyst. From XPS investigation, it is hypothesized that the improved performance of AT-treated MEAs is related to an improved interface between the catalyst and Nafion ionomer. Among potential explanations, this improvement may be caused by incorporation of the ionomer within the secondary pores of PtRu/C agglomerates, which generates a percolating network of ionomer between PtRu/C agglomerates in the catalyst layer. Furthermore, the decreased concentration of hydrophobic CF2 groups may help to enhance the hydrophilicity of the catalyst layer, thereby increasing the accessibility of methanol and resulting in better performance in the high current density region.

  1. The Presence of Turbulent and Ordered Local Structure within the ICME Shock-sheath and Its Contribution to Forbush Decrease

    Energy Technology Data Exchange (ETDEWEB)

    Shaikh, Zubair; Bhaskar, Ankush [Indian Institute of Geomagnetism (IIG), New Panvel, Navi Mumbai-410218 (India); Raghav, Anil, E-mail: raghavanil1984@gmail.com [University Department of Physics, University of Mumbai, Vidyanagari, Santacruz (E), Mumbai-400098 (India)

    2017-08-01

    The transient interplanetary disturbances evoke short-time cosmic-ray flux decrease, which is known as Forbush decrease. The traditional model and understanding of Forbush decrease suggest that the sub-structure of an interplanetary counterpart of coronal mass ejection (ICME) independently contributes to cosmic-ray flux decrease. These sub-structures, shock-sheath, and magnetic cloud (MC) manifest as classical two-step Forbush decrease. The recent work by Raghav et al. has shown multi-step decreases and recoveries within the shock-sheath. However, this cannot be explained by the ideal shock-sheath barrier model. Furthermore, they suggested that local structures within the ICME’s sub-structure (MC and shock-sheath) could explain this deviation of the FD profile from the classical FD. Therefore, the present study attempts to investigate the cause of multi-step cosmic-ray flux decrease and respective recovery within the shock-sheath in detail. A 3D-hodogram method is utilized to obtain more details regarding the local structures within the shock-sheath. This method unambiguously suggests the formation of small-scale local structures within the ICME (shock-sheath and even in MC). Moreover, the method could differentiate the turbulent and ordered interplanetary magnetic field (IMF) regions within the sub-structures of ICME. The study explicitly suggests that the turbulent and ordered IMF regions within the shock-sheath do influence cosmic-ray variations differently.

  2. Neon soft x-ray emission studies from the UNU-ICTP plasma focus operated with longer than optimal anode length

    International Nuclear Information System (INIS)

    Mohammadi, M A; Verma, R; Sobhanian, S; Wong, C S; Lee, S; Springham, S V; Tan, T L; Lee, P; Rawat, R S

    2007-01-01

    The UNU-ICTP plasma focus with a significantly longer than conventional anode can still be a reasonably good neon soft x-ray (SXR) source. The highest average neon SXR yield of 3.3 J was achieved at 3 mbar. The time difference between the two first peaks of the voltage probe signal at the radial collapse phase was found to be inversely related to the SXR yield, i.e. the smaller the time difference, the higher the yield and vice versa. The estimation of average current sheath speeds using the shadowgraphic method coupled with laser and focus peak timing signals showed that the average axial rundown speed is similar to the one obtained for the optimal anode length but the average radial compression speed is decreased significantly. The range of pressure for a good neon SXR yield, however, has become much narrower, making efficient plasma focus operation a very sensitive function of the filling gas pressure for longer than the optimal anode length

  3. A Radical Switch

    Directory of Open Access Journals (Sweden)

    Alexander Rappaport

    2017-09-01

    Full Text Available Architecture is the most vulnerable part of culture, almost doomed to destruction of its fundamentals, while the rise of its intellectual and creative level is badly needed. However, neither the resort to postmarxist French philosophy nor bringing the results of development of science and technology into architecture, neither computerization nor peculiarities of parametricism and deconstructivism are helpful. It can be stated that in the beginning of the third millennium architecture and architectural education are in stalemate. The way out is in a “radical” switch from comprehension of object space to the time and to the processes of thinking, designing and historical change in professional mentality. The interests must be focused not on the object, but on the process enabling the use of return reflexive strokes as well.

  4. Battery switch for downhole tools

    Science.gov (United States)

    Boling, Brian E.

    2010-02-23

    An electrical circuit for a downhole tool may include a battery, a load electrically connected to the battery, and at least one switch electrically connected in series with the battery and to the load. The at least one switch may be configured to close when a tool temperature exceeds a selected temperature.

  5. Improved switch-resistor packaging

    Science.gov (United States)

    Redmerski, R. E.

    1980-01-01

    Packaging approach makes resistors more accessible and easily identified with specific switches. Failures are repaired more quickly because of improved accessibility. Typical board includes one resistor that acts as circuit breaker, and others are positioned so that their values can be easily measured when switch is operated. Approach saves weight by using less wire and saves valuable panel space.

  6. Task Switching: A PDP Model

    Science.gov (United States)

    Gilbert, Sam J.; Shallice, Tim

    2002-01-01

    When subjects switch between a pair of stimulus-response tasks, reaction time is slower on trial N if a different task was performed on trial N--1. We present a parallel distributed processing (PDP) model that simulates this effect when subjects switch between word reading and color naming in response to Stroop stimuli. Reaction time on "switch…

  7. A CMOS Switched Transconductor Mixer

    NARCIS (Netherlands)

    Klumperink, Eric A.M.; Louwsma, S.M.; Wienk, Gerhardus J.M.; Nauta, Bram

    A new CMOS active mixer topology can operate at low supply voltages by the use of switches exclusively connected to the supply voltages. Such switches require less voltage headroom and avoid gate-oxide reliability problems. Mixing is achieved by exploiting two transconductors with cross-coupled

  8. Evaluation of Bcl-2, Bcl-x and Cleaved Caspase-3 in Malignant Peripheral Nerve Sheath Tumors and Neurofibromas

    Directory of Open Access Journals (Sweden)

    KARIN S. CUNHA

    2013-11-01

    Full Text Available AIMS: To study the expression of Bcl-2, Bcl-x, as well the presence of cleaved caspase-3 in neurofibromas and malignant peripheral nerve sheath tumors. The expression of Bcl-2 and Bcl-x and the presence of cleaved caspase 3 were compared to clinicopathological features of malignant peripheral nerve sheath tumors and their impact on survival rates were also investigated. MATERIALS AND METHODS: The evaluation of Bcl-2, Bcl-x and cleaved caspase-3 was performed by immunohistochemistry using tissue microarrays in 28 malignant peripheral nerve sheath tumors and 38 neurofibromas. Immunoquantification was performed by computerized digital image analysis. CONCLUSIONS: Apoptosis is altered in neurofibromas and mainly in malignant peripheral nerve sheath tumors. High levels of cleaved caspase-3 are more common in tumors with more aggressive histological features and it is associated with lower disease free survival of patients with malignant peripheral nerve sheath tumors.

  9. Amorphous metal based nanoelectromechanical switch

    KAUST Repository

    Mayet, Abdulilah M.

    2013-04-01

    Nanoelectromechanical (NEM) switch is an interesting ultra-low power option which can operate in the harsh environment and can be a complementary element in complex digital circuitry. Although significant advancement is happening in this field, report on ultra-low voltage (pull-in) switch which offers high switching speed and area efficiency is yet to be made. One key challenge to achieve such characteristics is to fabricate nano-scale switches with amorphous metal so the shape and dimensional integrity are maintained to achieve the desired performance. Therefore, we report a tungsten alloy based amorphous metal with fabrication process development of laterally actuated dual gated NEM switches with 100 nm width and 200 nm air-gap to result in <5 volts of actuation voltage (Vpull-in). © 2013 IEEE.

  10. The importance of anodic discharge of H2O in anodic oxygen-transfer reactions

    International Nuclear Information System (INIS)

    Vitt, J.E.; Johnson, D.C.

    1992-01-01

    This paper discusses difference voltammetry at rotated disk electrodes which are applied to a study of several anodic O-transfer reactions that appear to occur concurrently with O 2 evolution. This voltammetric technique was useful for extracting the rotation-dependent component of the total current from the large, virtually rotation-independent current for O 2 evolution. Data for oxidation of I - at Pt, Au, Pd, Ir, and glassy carbon electrodes show that the E 1/2 for IO - 3 production is correlated with the overpotential for O 2 evolution at these electrode materials. Data obtained at an Ir electrode for various reactions with widely varying E o values reveal uniform E 1/2 values closely correlated with the potential for onset of O 2 evolution in both alkaline and acidic solutions. The results support the conclusion that the anodic discharge of H 2 O is a prerequisite of these anodic O-transfer mechanisms

  11. Epithelial-mesenchymal transition in keloid tissues and TGF-β1-induced hair follicle outer root sheath keratinocytes.

    Science.gov (United States)

    Yan, Li; Cao, Rui; Wang, Lianzhao; Liu, Yuanbo; Pan, Bo; Yin, Yanhua; Lv, Xiaoyan; Zhuang, Qiang; Sun, Xuejian; Xiao, Ran

    2015-01-01

    Keloid is a skin fibrotic disease with the characteristics of recurrence and invasion, its pathogenesis still remains unrevealed. The epithelial-mesenchymal transition (EMT) is critical for wound healing, fibrosis, recurrence, and invasion of cancer. We sought to investigate the EMT in keloid and the mechanism through which the EMT regulates keloid formation. In keloid tissues, the expressions of EMT-associated markers and transforming growth factor (TGF)-β1/Smad3 signaling were examined by immunohistochemistry. In the keloid epidermis and dermal tissue, the expressions of genes related to the regulation of skin homeostasis, fibroblast growth factor receptor 2 (FGFR2) and p63, were analyzed using quantitative real-time polymerase chain reaction. The results showed that accompanying the loss of the epithelial marker E-cadherin and the gain of the mesenchymal markers fibroblast-specific protein 1 (FSP1) and vimentin in epithelial cells from epidermis and skin appendages, and in endothelial cells from dermal microvessels, enhanced TGF-β1 expression and Smad3 phosphorylation were noted in keloid tissues. Moreover, alternative splicing of the FGFR2 gene switched the predominantly expressed isoform from FGFR2-IIIb to -IIIc, concomitant with the decreased expression of ΔNp63 and TAp63, which changes might partially account for abnormal epidermis and appendages in keloids. In addition, we found that TGF-β1-induced hair follicle outer root sheath keratinocytes (ORSKs) and normal skin epithelial cells underwent EMT in vitro with ORSKs exhibiting more obvious EMT changes and more similar expression profiles for EMT-associated and skin homeostasis-related genes as in keloid tissues, suggesting that ORSKs might play crucial roles in the EMT in keloids. Our study provided insights into the molecular mechanisms mediating the EMT pathogenesis of keloids. © 2015 by the Wound Healing Society.

  12. Switching Phenomena in a System with No Switches

    Science.gov (United States)

    Preis, Tobias; Stanley, H. Eugene

    2010-02-01

    It is widely believed that switching phenomena require switches, but this is actually not true. For an intriguing variety of switching phenomena in nature, the underlying complex system abruptly changes from one state to another in a highly discontinuous fashion. For example, financial market fluctuations are characterized by many abrupt switchings creating increasing trends ("bubble formation") and decreasing trends ("financial collapse"). Such switching occurs on time scales ranging from macroscopic bubbles persisting for hundreds of days to microscopic bubbles persisting only for a few seconds. We analyze a database containing 13,991,275 German DAX Future transactions recorded with a time resolution of 10 msec. For comparison, a database providing 2,592,531 of all S&P500 daily closing prices is used. We ask whether these ubiquitous switching phenomena have quantifiable features independent of the time horizon studied. We find striking scale-free behavior of the volatility after each switching occurs. We interpret our findings as being consistent with time-dependent collective behavior of financial market participants. We test the possible universality of our result by performing a parallel analysis of fluctuations in transaction volume and time intervals between trades. We show that these financial market switching processes have properties similar to those of phase transitions. We suggest that the well-known catastrophic bubbles that occur on large time scales—such as the most recent financial crisis—are no outliers but single dramatic representatives caused by the switching between upward and downward trends on time scales varying over nine orders of magnitude from very large (≈102 days) down to very small (≈10 ms).

  13. Uncommonly high levels of 3-deoxyanthocyanidins and antioxidant capacity in the leaf sheaths of dye sorghum

    NARCIS (Netherlands)

    Kayode, A.P.P.; Nout, M.J.R.; Linnemann, A.R.; Hounhouigan, J.D.; Berghofer, E.; Siebenhandl-Ehn, S.

    2011-01-01

    Extracts from leaf sheaths of farmers varieties of dye sorghum cultivated and used in Benin as a source of biocolorings were analyzed for their anthocyanidin and phenolic contents, as well as their antioxidant capacity. The aim was to identify and quantify the types of anthocyanin and phenolic

  14. Study on the Mechanical Properties of Stay Cable HDPE Sheathing Fatigue in Dynamic Bridge Environments

    Directory of Open Access Journals (Sweden)

    Danhui Dan

    2015-08-01

    Full Text Available As the main force-bearing component of a cable-stayed bridge, a durable stay cable is paramount to the safety and durability of the entire bridge. High-density polyethylene (HDPE sheathing is the main protective component of a stay cable and is the key to insuring cable durability. To address the issue of HDPE sheathing fracture on service, strain level data for in-service, HDPE bridge cable sheathing was used in this study as the basis for HDPE material aging and fatigue testing. A fatigue yield phenomenon with a yield platform on the hysteresis curve of the fatigue cycles is observed by the fatigue test. The parameters to describe this phenomenon are proposed and defined in this paper. A preliminary examination of the relationship between these parameters and the factors, such as the number of cycles, the strain amplitude, and strain rate, are presented. Based on the results obtained, it is suggested that the condition of fatigue yield of HDPE sheathing be defined as the fatigue durability limit state for the purposes of durability design, assessment, and protection of cable-stayed bridges.

  15. Microstructure, texture and critical current of Ag-sheathed 2223 multifilament tapes

    DEFF Research Database (Denmark)

    Liu, Y.L.; Wang, W.G.; Poulsen, H.F.

    1999-01-01

    An Ag-sheathed 2223 multifilament tape was produced by the powder-in-tube method. The various parts of the tape were heat treated at different temperatures under reduced oxygen partial pressure. The microstructure and the texture were characterized by synchrotron x-ray diffraction and SEM...

  16. Magnetically modified sheaths of Leptothrix sp as an adsorbent for Amido black 10B removal

    Czech Academy of Sciences Publication Activity Database

    Angelova, R.; Baldíková, E.; Pospíšková, K.; Šafaříková, Miroslava; Šafařík, Ivo

    2017-01-01

    Roč. 427, April (2017), s. 314-319 ISSN 0304-8853 Institutional support: RVO:60077344 Keywords : Leptothrix sp. * sheaths * magnetic fluid * magnetic iron oxide * magnetic adsorbent * Amido black 10B Subject RIV: DJ - Water Pollution ; Quality OBOR OECD: Materials engineering Impact factor: 2.630, year: 2016

  17. Sealed coupling for an electrical heating conductor with coaxial sheath (pattern 1964)

    International Nuclear Information System (INIS)

    Arragon, Ph.; Aubert-Chevallier, R.; Gentil, J.; Seguin, M.; Vilcot, M.; Villiers, J.

    1965-01-01

    Many irradiation devices call for supplementary electrical heating which can provide a constant temperature. We describe a coupling whose high performance makes it possible for the sheathed electrical resistance to provide maximum power. Since this coupling is sealed and does not require special cooling, it may be placed in any position on the irradiation device. (authors) [fr

  18. CANDU fuel sheath integrity and oxide layer thickness determination by Eddy current technique

    International Nuclear Information System (INIS)

    Gheorghe, Gabriela; Man, Ion; Parvan, Marcel; Valeca, Serban

    2010-01-01

    This paper presents results concerning the integrity assessment of the fuel elements cladding and measurements of the oxide layer on sheaths, using the eddy current technique. Flaw detection using eddy current provides information about the integrity of fuel element sheath or presence of defects in the sheath produced by irradiation. The control equipment consists of a flaw detector with eddy currents, operable in the frequency range 10 Hz to 10 MHz, and a differential probe. The calibration of the flaw detector is done using artificial defects (longitudinal, transversal, external and internal notches, bored and unbored holes) obtained on Zircaloy-4 tubes identical to those out of which the sheath of the CANDU fuel element is manufactured (having a diameter of 13.08 mm and a wall thickness of 0.4 mm). When analyzing the behavior of the fuel elements' cladding facing the corrosion is important to know the thickness of the zirconium oxide layer. The calibration of the device measuring the thickness of the oxide layer is done using a Zircaloy-4 tube identical to that which the cladding of the CANDU fuel element is manufactured of, and calibration foils, as well. (authors)

  19. Analysis of rice PDR-like ABC transporter genes in sheath blight resistance

    Science.gov (United States)

    Sheath blight caused by Rhizoctonia solani is one of the most damaging diseases of rice worldwide. To understand the molecular mechanism of resistance, we identified 450 differentially expressed genes in a resistant rice cultivar Jasmine 85 after R. solani infection with a combination of DNA microar...

  20. A balloon protection sheath to prevent peripheral embolization during aortoiliac endovascular procedures

    NARCIS (Netherlands)

    Reekers, J. A.

    1998-01-01

    Peripheral embolization is a known complication occurring during aortoiliac recanalization. In particular, acute, fresh thrombotic occlusions, with a history shorter than 6 months, have a high risk for peripheral embolization. We describe a balloon occlusion sheath used to manage embolic material

  1. Using kinetic models to predict thermal degradation of fire-retardant-treated plywood roof sheathing

    Science.gov (United States)

    Patricia Lebow; Jerrold E. Winandy; Patricia K. Lebow

    2003-01-01

    Between 1985-1995 a substantial number of multifamily housing units in the Eastern and Southern U.S. experienced problems with thermally degraded fire-retardant-treated (FRT) plywood roof sheathing. A series of studies conducted at the USDA Forest Service, Forest Products Laboratory (FPL), examined the materials, chemical mechanisms, and process implications and has...

  2. Characterization of tail sheath protein of giant bacteriophage φKZ Pseudomonas aeruginosa

    International Nuclear Information System (INIS)

    Kurochkina, Lidia P.; Aksyuk, Anastasia A.; Sachkova, Maria Yu.; Sykilinda, Nina N.; Mesyanzhinov, Vadim V.

    2009-01-01

    The tail sheath protein of giant bacteriophage φKZ Pseudomonas aeruginosa encoded by gene 29 was identified and its expression system was developed. Localization of the protein on the virion was confirmed by immunoelectron microscopy. Properties of gene product (gp) 29 were studied by electron microscopy, immunoblotting and limited trypsinolysis. Recombinant gp29 assembles into the regular tubular structures (polysheaths) of variable length. Trypsin digestion of gp29 within polysheaths or extended sheath of virion results in specific cleavage of the peptide bond between Arg135 and Asp136. However, this cleavage does not affect polymeric structure of polysheaths, sheaths and viral infectivity. Digestion by trypsin of the C-truncated gp29 mutant, lacking the ability to self-assemble, results in formation of a stable protease-resistant fragment. Although there is no sequence homology of φKZ proteins to proteins of other bacteriophages, some characteristic biochemical properties of gp29 revealed similarities to the tail sheath protein of bacteriophage T4.

  3. A novel single step percutaneous access sheath: the initial human experience.

    Science.gov (United States)

    Baldwin, D Duane; Maynes, Lincoln J; Desai, Premal J; Jellison, Forrest C; Tsai, Christopher K; Barker, Gary R

    2006-01-01

    A novel 1-step percutaneous access sheath NS has been developed that allows the insertion of a dilating balloon and renal access sheath in a single step. We present the initial human experience with this sheath. We performed a retrospective chart and database review of the initial 30 consecutive patients undergoing percutaneous nephrostolithotomy using the NS. Data collected included patient demographics, operative and recovery parameters, and complications. Mean patient age was 50.4 years (range 11 to 81), mean body mass index was 31.63 kg/m(2) (range 17.1 to 65) and mean preoperative stone area was 6.23 cm(2) (range 1 to 14.6). Six and 3 patients had full and partial staghorn calculi, respectively. Access was achieved via the upper pole in 16 patients, middle pole in 7 and lower pole in 7. Mean operative time was 114.8 minutes (range 61 to 237). Mean estimated blood loss was 145.5 cc (range 10 to 500) and mean postoperative hospital stay was 4.89 days (range 2 to 14). A total of 23 patients (76.7%) had no residual calculi on postoperative computerized tomography, 5 (16.7%) had residual fragments 4 mm or less and 2 (6.7%) had residual stone fragments greater than 4 mm. There were no complications related to the NS. The NS is safe, easy to use and has potential advantages compared to currently available renal access sheaths.

  4. Self-sustaining relativistic ionization wave launched by a sheath field

    Science.gov (United States)

    Arefiev, Alexey; McCormick, Matt; Quevedo, Hernan; Bengtson, Roger; Ditmire, Todd

    2013-10-01

    We present experimental evidence supported by particle-in-cell (PIC) simulations of a self-sustaining relativistic ionization wave launched into a surrounding gas by the sheath field of a high energy density plasma. We create a plasma filament with hot electrons by irradiating a supersonic clustering gas jet with a short pulse laser (115 fs) at an intensity of 5 ×1017 W/cm2. In contrast with a single atom, a cluster of atoms produces super-ponderomotive electrons in the field of the laser. These electrons generate a sheath field at the edge of the plasma filament strong enough to ionize the gas atoms in the sheath. We observe that a collisionless ionization wave is launched in this regime, propagating radially through the gas at up to 0.5 c after the laser has passed. The expansion of the resulting plasma filament due to the ionization wave occurs in about 2 ps, more than doubling the initial radius of the filament. The remarkable longevity of the wave without continuous energy deposition into the electron population is explained by a moving field structure that traps the hot electrons near the boundary. 2D PIC simulations confirm that the trapped hot electrons maintain a sheath field required for the ionization despite the significant expansion of the filament.

  5. Thermographic determination of the sheath heat transmission coefficient in a high density plasma

    NARCIS (Netherlands)

    van den Berg, M. A.; Bystrov, K.; Pasquet, R.; Zielinski, J. J.; De Temmerman, G.

    2013-01-01

    Experiments were performed in the Pilot-PSI linear plasma device, to determine the sheath heat transmission coefficients in a high recycling regime under various conditions of density (1–20 × 1020 m−3) and plasma composition (H2, Ar, N2) relevant for the

  6. Sheath and arc-column voltages in high-pressure arc discharges

    International Nuclear Information System (INIS)

    Benilov, M S; Benilova, L G; Li Heping; Wu Guiqing

    2012-01-01

    Electrical characteristics of a 1 cm-long free-burning atmospheric-pressure argon arc are calculated by means of a model taking into account the existence of a near-cathode space-charge sheath and the discrepancy between the electron and heavy-particle temperatures in the arc column. The computed arc voltage exhibits a variation with the arc current I similar to the one revealed by the experiment and exceeds experimental values by no more than approximately 2 V in the current range 20-175 A. The sheath contributes about two-thirds or more of the arc voltage. The LTE model predicts a different variation of the arc voltage with I and underestimates the experimental values appreciably for low currents but by no more than approximately 2 V for I ≳ 120 A. However, the latter can hardly be considered as a proof of unimportance of the space-charge sheath at high currents: the LTE model overestimates both the resistance of the bulk of the arc column and the resistance of the part of the column that is adjacent to the cathode, and this overestimation to a certain extent compensates for the neglect of the voltage drop in the sheath. Furthermore, if the latter resistance were evaluated in the framework of the LTE model in an accurate way, then the overestimation would be still much stronger and the obtained voltage would significantly exceed those observed in the experiment.

  7. Magnetic sheath effect on the gross and net erosion rates due to impurities

    Science.gov (United States)

    Mellet, N.; Pégourié, B.; Martin, C.; Gunn, J. P.; Bufferand, H.; Roubin, P.

    2016-02-01

    Simulations of impurity trajectories in deuterium plasmas in the vicinity of the surface are performed by taking into account the magnetic sheath in conditions relevant for ITER and WEST. We show that the magnetic sheath has a strong effect on the average impact angle of impurities in divertor conditions and that it can lead to an increase of ≈ 60% at the gross erosion maximum for neon (Ne+4) compared to the case when only the cyclotron motion is considered. The evaluation of the net erosion has been undertaken by retaining local redeposition of tungsten (W). We investigate how it is affected by the sheath magnetic potential profile. The largest effect is however observed when an energy distribution is considered. In this case the number of particles that manage to exit the sheath is larger as it is dominated by the more energetic particles. The comparison with other work is also discussed. The application to a scenario of the WEST project is finally performed, which exhibits a moderate, however non negligible, erosion of the plasma facing components.

  8. Effects of Reentry Plasma Sheath on Mutual-Coupling Property of Array Antenna

    Directory of Open Access Journals (Sweden)

    B. W. Bai

    2015-01-01

    Full Text Available A plasma sheath enveloping a reentry vehicle would cause the failure of on-board antennas, which is an important effect that contributes to the “blackout” problem. The method of replacing the on-board single antenna with the array antennas and using beamforming technology has been proposed to mitigate “blackout” problem by many other researchers. Because the plasma sheath is a reflective medium, plasma will alter the mutual coupling between array elements and degrade the beamforming performance of array antenna. In this paper, the effects of the plasma sheath on the mutual coupling properties between adjacent array elements are studied utilizing the algorithm of finite integration technique. Results show that mutual coupling coefficients of array elements are deteriorating more seriously with the decrease of collision frequency. Moreover, when electron density and collision frequency are both large, plasma sheath improves the mutual coupling property of array elements; this conclusion suggests that replacing the on-board single antenna with the array antennas and using beamforming technology can be adopted to mitigate the blackout problem in this condition.

  9. Calculation of the radial electric field with RF sheath boundary conditions in divertor geometry

    Science.gov (United States)

    Gui, B.; Xia, T. Y.; Xu, X. Q.; Myra, J. R.; Xiao, X. T.

    2018-02-01

    The equilibrium electric field that results from an imposed DC bias potential, such as that driven by a radio frequency (RF) sheath, is calculated using a new minimal two-field model in the BOUT++ framework. Biasing, using an RF-modified sheath boundary condition, is applied to an axisymmetric limiter, and a thermal sheath boundary is applied to the divertor plates. The penetration of the bias potential into the plasma is studied with a minimal self-consistent model that includes the physics of vorticity (charge balance), ion polarization currents, force balance with E× B , ion diamagnetic flow (ion pressure gradient) and parallel electron charge loss to the thermal and biased sheaths. It is found that a positive radial electric field forms in the scrape-off layer and it smoothly connects across the separatrix to the force-balanced radial electric field in the closed flux surface region. The results are in qualitative agreement with the experiments. Plasma convection related to the E× B net flow in front of the limiter is also obtained from the calculation.

  10. Uniaxial Strain Induced Critical Current Degradation of Ag-Sheathed Bi-2212 Round Wire

    NARCIS (Netherlands)

    Dai, Chao; Qin, Jinggang; Liu, Bo; Liu, Peihang; Wu, Yu; Nijhuis, Arend; Zhou, Chao; Li, Chenshan; Hao, Qingbin; Liu, Sheng

    2018-01-01

    The critical current degradation of Bi-2212 Ag-sheathed round wire subjected to uniaxial strain was studied at 4.2 K in 14 T background field. The strains applied on the sample are both tension and compression. The additional tensile strain caused by the difference in thermal expansion between the

  11. CT saber-sheath trachea. Correlation with clinical, chest radiographic and functional findings

    International Nuclear Information System (INIS)

    Trigaux, J.P.; Hermes, G.; Dubois, P.; Beers, B. van; Delaunois, L.; Jamart, J.

    1994-01-01

    The diagnosis of saber-sheath trachea is easy at CT due to its cross-sectional imaging, but the significance of this CT sign has not been evaluated in the diagnosis of chronic obstructive pulmonary disease (COPD). Various signs of COPD were compared between a series of 20 patients with a saber-sheath trachea at CT (tracheal index ≤66%) and a group of 20 pneumologic control patients without saber-sheath trachea (tracheal index ≥70%). These signs include clinical and standard radiographic indices of COPD, sternum-spine distance and 3 functional tests of COPD: forced expiratory volume in one second, carbon monoxide diffusing lung capacity, and funtional residual capacity (FRC). A significant difference was found between the 2 groups, concerning the values of FRC and of sternum-spine distance (p -2 ). The tracheal index was significantly correlated with the FRC values and with the sternum-spine distance. No other significant difference was observed. It is concluded that saber-sheath trachea is basically a sign of hyperinflation. (orig./MG)

  12. Thrombus Development on a Transseptal Sheath in the Right Atrium Before Electrical Pulmonary Vein Isolation

    Directory of Open Access Journals (Sweden)

    Nieves Romero-Rodriguez

    2008-02-01

    Full Text Available We describe the case of a patient who developed a thrombus on the transseptal sheath in the right atrium before transseptal puncture for circumferential pulmonary vein isolation for paroxysmal atrial fibrillation treatment. The use of intracardiac echocardiography allowed to its identification and probably prevented the patient from suffering a serious thromboembolic complication.

  13. Effects of a reentry plasma sheath on the beam pointing properties of an array antenna

    Science.gov (United States)

    Bai, Bowen; Liu, Yanming; Lin, Xiaofang; Li, Xiaoping

    2018-03-01

    The reduction in the gain of an on-board antenna caused by a reentry plasma sheath is an important effect that contributes to the reentry "blackout" problem. Using phased array antenna and beamforming technology could provide higher gain and an increase in the communication signal intensity. The attenuation and phase delay of the electromagnetic (EM) waves transmitting through the plasma sheath are direction-dependent, and the radiation pattern of the phased array antenna is affected, leading to a deviation in the beam pointing. In this paper, the far-field pattern of a planar array antenna covered by a plasma sheath is deduced analytically by considering both refraction and mutual coupling effects. A comparison between the analytic results and the results from an electromagnetic simulation is carried out. The effect of the plasma sheath on the radiation pattern and the beam pointing errors of the phased array antenna is studied systematically, and the derived results could provide useful information for the correction of pointing errors.

  14. Screening and sheath formation in a nonequilibrium mixed Cairns-Tsallis electron distribution

    Energy Technology Data Exchange (ETDEWEB)

    Bouzit, Omar; Gougam, Leila Ait; Tribeche, Mouloud [Faculty of Physics, Theoretical Physics Laboratory (TPL), University of Bab-Ezzouar, USTHB, B.P. 32, El Alia, Algiers (Algeria)

    2015-05-15

    The effects of electron nonextensivity for a given nonthermality state, on Debye shielding and electrostatic sheath formation are examined. A physically meaningful Cairns-Tsallis distribution is outlined and a generalized expression for the Debye screening length λ{sub D}{sup q,α} is obtained. It is shown that an increase of the entropic index q causes λ{sub D}{sup q,α} to decrease whatever the amount of plasma nonthermality α. In addition, smaller pertinent values of q along with relatively higher values of α provide larger values of λ{sub D}{sup q,α}. The shielded electrostatic potential falls off as a function of distance more slowly as α increases, a result somewhat analogous to the dynamical shielding decrease (albeit in a different context) of a free charge as it begins to move. Moreover, smaller pertinent values of q along with relatively higher values of α are found to involve higher ion drift speed v{sub i0} for proper sheath formation. As α increases, the sheath electrostatic potential-gradient dΨ{sub s}/dξ becomes abruptly steep slowing down the energetic electrons leakage to the wall. Moreover, the sheath thickness broadens as the electron nonthermality strengthens.

  15. Forced convection mass deposition and heat transfer onto a cylinder sheathed by protective garments

    NARCIS (Netherlands)

    Ambesi, D.; Kleijn, C.R.; Hartog, E.A. den; Bouma, R.H.B.; Brasser, P.

    2014-01-01

    In chemical, biological, radiological, and nuclear protective clothing, a layer of activated carbon material in between two textile layers provides protection against hazardous gases. A cylinder in cross flow, sheathed by such material, is generally used to experimentally test the garment

  16. Forced convection mass deposition and heat transfer onto a cylinder sheathed by protective garments

    NARCIS (Netherlands)

    Ambesi, D.; Kleijn, C.R.; Den Hartog, E.A.; Bouma, R.H.B.; Brasser, P.

    2013-01-01

    In chemical, biological, radiological, and nuclear protective clothing, a layer of activated carbon material in between two textile layers provides protection against hazardous gases. A cylinder in cross flow, sheathed by such material, is generally used to experimentally test the garment

  17. Recurring intracranial malignant peripheral nerve sheath tumor: case report and systematic review of the literature

    NARCIS (Netherlands)

    van den Munckhof, Pepijn; Germans, Menno R.; Schouten-van Meeteren, Antoinette Y. N.; Oldenburger, Foppe; Troost, Dirk; Vandertop, W. Peter

    2011-01-01

    To report the clinical presentation and management of an intracranial frontoparietal malignant peripheral nerve sheath tumor (MPNST) and its recurrence in a 6-year-old girl, along with a systematic review of the literature. A previously healthy 6-year-old girl presented with severe signs of

  18. Tearing mode of a neutral current sheath in a plasma flux

    International Nuclear Information System (INIS)

    Gubchenko, V.M.

    1982-01-01

    The linear stage of the tearing mode of diffusion neutral current sheath immersed in the plasma flux directed along the magnetic field is considered. It follows form the obtained dispersion characteristics that the flux exerts a stabilizing effect on the mode and leads to appearance of phase drift velocity

  19. Fundamental Investigation of Si Anode in Li-Ion Cells

    Science.gov (United States)

    Wu, James J.; Bennett, William R.

    2012-01-01

    Silicon is a promising and attractive anode material to replace graphite for high capacity lithium ion cells since its theoretical capacity is approximately 10 times of graphite and it is an abundant element on earth. However, there are challenges associated with using silicon as Li-ion anode due to the significant first cycle irreversible capacity loss and subsequent rapid capacity fade during cycling. In this paper, cyclic voltammetry and electrochemical impedance spectroscopy are used to build a fundamental understanding of silicon anodes. The results show that it is difficult to form the SEI film on the surface of Si anode during the first cycle, the lithium ion insertion and de-insertion kinetics for Si are sluggish, and the cell internal resistance changes with the state of lithiation after electrochemical cycling. These results are compared with those for extensively studied graphite anodes. The understanding gained from this study will help to design better Si anodes.

  20. Redox Stable Anodes for Solid Oxide Fuel Cells

    Directory of Open Access Journals (Sweden)

    Guoliang eXiao

    2014-06-01

    Full Text Available Solid oxide fuel cells (SOFCs can convert chemical energy from the fuel directly to electrical energy with high efficiency and fuel flexibility. Ni-based cermets have been the most widely adopted anode for SOFCs. However, the conventional Ni-based anode has low tolerance to sulfur-contamination, is vulnerable to deactivation by carbon build-up (coking from direct oxidation of hydrocarbon fuels, and suffers volume instability upon redox cycling. Among these limitations, the redox instability of the anode is particularly important and has been intensively studied since the SOFC anode may experience redox cycling during fuel cell operations even with the ideal pure hydrogen as the fuel. This review aims to highlight recent progresses on improving redox stability of the conventional Ni-based anode through microstructure optimization and exploration of alternative ceramic-based anode materials.

  1. Fabrication of ultra thin anodic aluminium oxide membranes by low anodization voltages

    Science.gov (United States)

    Pastore, I.; Poplausks, R.; Apsite, I.; Pastare, I.; Lombardi, F.; Erts, D.

    2011-06-01

    Formation of ultrathin anodised aluminium oxide (AAO) membranes with high aspect ratio by Al anodization in sulphuric and oxalic acids at low potentials was investigated. Low anodization potentials ensure slow electrochemical reaction speeds and formation of AAO membranes with pore diameter and thickness below 20 nm and 70 nm respectively. Minimum time necessary for formation of continuous AAO membranes was determined. AAO membrane pore surface was covered with polymer Paraloid B72TM to transport it to the selected substrate. The fabricated ultra thin AAO membranes could be used to fabricate nanodot arrays on different surfaces.

  2. Model Reduction of Switched Systems Based on Switching Generalized Gramians

    DEFF Research Database (Denmark)

    Shaker, Hamid Reza; Wisniewski, Rafal

    2012-01-01

    In this paper, a general method for model order reduction of discrete-time switched linear systems is presented. The proposed technique uses switching generalized gramians. It is shown that several classical reduction methods can be developed into the generalized gramian framework for the model...... reduction of linear systems and for the reduction of switched systems. Discrete-time balanced reduction within a specified frequency interval is taken as an example within this framework. To avoid numerical instability and to increase the numerical efficiency, a generalized gramian-based Petrov...

  3. The mechanism of electroforming of metal oxide memristive switches

    Science.gov (United States)

    Joshua Yang, J.; Miao, Feng; Pickett, Matthew D.; Ohlberg, Douglas A. A.; Stewart, Duncan R.; Lau, Chun Ning; Williams, R. Stanley

    2009-05-01

    Metal and semiconductor oxides are ubiquitous electronic materials. Normally insulating, oxides can change behavior under high electric fields—through 'electroforming' or 'breakdown'—critically affecting CMOS (complementary metal-oxide-semiconductor) logic, DRAM (dynamic random access memory) and flash memory, and tunnel barrier oxides. An initial irreversible electroforming process has been invariably required for obtaining metal oxide resistance switches, which may open urgently needed new avenues for advanced computer memory and logic circuits including ultra-dense non-volatile random access memory (NVRAM) and adaptive neuromorphic logic circuits. This electrical switching arises from the coupled motion of electrons and ions within the oxide material, as one of the first recognized examples of a memristor (memory-resistor) device, the fourth fundamental passive circuit element originally predicted in 1971 by Chua. A lack of device repeatability has limited technological implementation of oxide switches, however. Here we explain the nature of the oxide electroforming as an electro-reduction and vacancy creation process caused by high electric fields and enhanced by electrical Joule heating with direct experimental evidence. Oxygen vacancies are created and drift towards the cathode, forming localized conducting channels in the oxide. Simultaneously, O2- ions drift towards the anode where they evolve O2 gas, causing physical deformation of the junction. The problematic gas eruption and physical deformation are mitigated by shrinking to the nanoscale and controlling the electroforming voltage polarity. Better yet, electroforming problems can be largely eliminated by engineering the device structure to remove 'bulk' oxide effects in favor of interface-controlled electronic switching.

  4. Battery, especially for portable devices, has an anode containing silicon

    OpenAIRE

    Kan, S.Y.

    2002-01-01

    The anode (2) contains silicon. A battery with a silicon-containing anode is claimed. An Independent claim is also included for a method used to make the battery, comprising the doping of a silicon substrate (1) with charge capacity-increasing material (preferably boron, phosphorous or arsenic), etching the doped substrate layer in order to increase its porosity, and applying a cathode (3) in the form of a lithium oxide compound onto the resulting anode and applying an electrolyte (4) to the ...

  5. The influence of coke source on anode performance

    Science.gov (United States)

    Jonville, C.; Thomas, J. C.; Dreyer, C.

    1995-08-01

    The role of anode raw material has long been debated in the aluminum smelting industry. By examining data accumulated from two similar smelting operations of Aluminium Pechiney, this article focuses on the differences in performance of anodes that can be attributed to the raw materials. The results suggest that good anode performance can be obtained for a range of cokes, provided that the operation is well designed and carefully operated.

  6. Cooling for a rotating anode X-ray tube

    Science.gov (United States)

    Smither, Robert K.

    1998-01-01

    A method and apparatus for cooling a rotating anode X-ray tube. An electromagnetic motor is provided to rotate an X-ray anode with cooling passages in the anode. These cooling passages are coupled to a cooling structure located adjacent the electromagnetic motor. A liquid metal fills the passages of the cooling structure and electrical power is provided to the motor to rotate the anode and generate a rotating magnetic field which moves the liquid metal through the cooling passages and cooling structure.

  7. The corrosion protection of 2219-T87 aluminum by anodizing

    Science.gov (United States)

    Danford, M. D.

    1991-01-01

    Various types of anodizing coatings were studied for 2219-T87 aluminum. These include both type II and type III anodized coats which were water sealed and a newly developed and proprietary Magnaplate HCR (TM) coat. Results indicate that type II anodizing is not much superior to type II anodizing as far as corrosion protection for 2219-T87 aluminum is concerned. Magnaplate HCR (TM) coatings should provide superior corrosion protection over an extended period of time using a coating thickness of 51 microns (2.0 mils).

  8. DETERMINANT OF DOWNWARD AUDITOR SWITCHING

    Directory of Open Access Journals (Sweden)

    Totok Budisantoso

    2017-12-01

    Full Text Available Abstract: Determinant of Downward Auditor Switching. This study examines the factors that influence downward auditor switching in five ASEAN countries. Fixed effect logistic regression was used as analytical method. This study found that opinion shopping occurred in ASEAN, especially in distress companies. Companies with complex businesses will retain the Big Four auditors to reduce complexity and audit costs. Audit and public committees serve as guardians of auditor quality. On the other hand, shareholders failed to maintain audit quality. It indicates that there is entrenchment effect in auditor switching.

  9. Influence of the anodizing process variables on the acidic properties of anodic alumina films

    Directory of Open Access Journals (Sweden)

    D.E. Boldrini

    Full Text Available Abstract In the present work, the effect of the different variables involved in the process of aluminum anodizing on the total surface acidity of the samples obtained was studied. Aluminum foils were treated by the electro-chemical process of anodic anodizing within the following variable ranges: concentration = 1.5-2.5 M; temperature = 303-323 K; voltage = 10-20 V; time = 30-90 min. The total acidity of the samples was characterized by two different methods: acid-base titration using Hammett indicators and potentiometric titration. The results showed that anodizing time, temperature and concentration were the main variables that determined the surface acid properties of the samples, and to a lesser extent voltage. Acidity increased with increasing concentration of the electrolytic bath, whereas the rest of the variables had the opposite effect. The results obtained provide a novel tool for variable selection in order to use synthetized materials as catalytic supports, adding to previous research based on the morphology of alumina layers.

  10. The effect of oxygen on the failure of reactor fuel sheaths during a postulated loss-of-coolant accident

    International Nuclear Information System (INIS)

    Ferner, J.; Rosinger, H.E.

    1983-09-01

    The failure model for Zircaloy-4 reactor fuel sheaths was used to study the effect of steam oxidation on sheath burst strain. The model, in the form of a computer program called BURST-3, was used to calculate burst strain for a Zircaloy-4 sheath under arbitrary pressure and temperature sequences in an oxidizing (steam) atmosphere. In particular, BURST-3 was used in a parametric study to predict the sheath behaviour in steam as compared to an inert atmosphere, the effect of heating rate, and the effect of circumferential temperature variations on burst strain. It was found that fuel sheath oxidation, which decreases burst strain, becomes increasingly important with increasing temperature and/or time. An effective oxygen concentration of greater than 0.27 wt. percent will cause the sheath to fail with a negligible strain. The hottest region of a sheath will have the highest oxygen concentration, the largest localized strain, and will be the site of failure. The model predictions were compared to experimental data in the range 900 to 1600 K. Agreement between theory and experiment for all three heating rates (5, 25, and 100 K.s -1 ) was very good

  11. Physics of the intermediate layer between a plasma and a collisionless sheath and mathematical meaning of the Bohm criterion

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, N. A.; Benilov, M. S. [Departamento de Fisica, CCCEE, Universidade da Madeira Largo do Municipio, 9000 Funchal (Portugal)

    2012-07-15

    A transformation of the ion momentum equation simplifies a mathematical description of the transition layer between a quasi-neutral plasma and a collisionless sheath and clearly reveals the physics involved. Balance of forces acting on the ion fluid is delicate in the vicinity of the sonic point and weak effects come into play. For this reason, the passage of the ion fluid through the sonic point, which occurs in the transition layer, is governed not only by inertia and electrostatic force but also by space charge and ion-atom collisions and/or ionization. Occurrence of different scenarios of asymptotic matching in the plasma-sheath transition is analyzed by means of simple mathematical examples, asymptotic estimates, and numerical calculations. In the case of a collisionless sheath, the ion speed distribution plotted on the logarithmic scale reveals a plateau in the intermediate region between the sheath and the presheath. The value corresponding to this plateau has the meaning of speed with which ions leave the presheath and enter the sheath; the Bohm speed. The plateau is pronounced reasonably well provided that the ratio of the Debye length to the ion mean free path is of the order of 10{sup -3} or smaller. There is no such plateau if the sheath is collisional and hence no sense in talking of a speed with which ions enter the sheath.

  12. X-ray tube with rotating anode

    International Nuclear Information System (INIS)

    1977-01-01

    Radiation tube, with a rotating anode is located in a vacuum tight housing by means of at least one bearing, characterised in that the bearing is a sliding bearing wherein at least the mutually working load contact surfaces consist mainly of a metal or metallic alloy and are not chemically attacked, as a bearing lubricant material is used containing a Ga-alloy, with a low melting point and a low vapour pressure, which is in direct contact with the metal working surfaces. (G.C.)

  13. Composite anode for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    de Guzman, Rhet C.; Ng, K.Y. Simon; Salley, Steven O.

    2018-03-06

    A composite anode for a lithium-ion battery is manufactured from silicon nanoparticles having diameters mostly under 10 nm; providing an oxide layer on the silicon nanoparticles; dispersing the silicon nanoparticles in a polar liquid; providing a graphene oxide suspension; mixing the polar liquid containing the dispersed silicone nanoparticles with the graphene oxide suspension to obtain a composite mixture; probe-sonicating the mixture for a predetermined time; filtering the composite mixture to obtain a solid composite; drying the composite; and reducing the composite to obtain graphene and silicon.

  14. Low temperature anodic bonding to silicon nitride

    DEFF Research Database (Denmark)

    Weichel, Steen; Reus, Roger De; Bouaidat, Salim

    2000-01-01

    Low-temperature anodic bonding to stoichiometric silicon nitride surfaces has been performed in the temperature range from 3508C to 4008C. It is shown that the bonding is improved considerably if the nitride surfaces are either oxidized or exposed to an oxygen plasma prior to the bonding. Both bulk...... and thin-film glasses were used in the bonding experiments. Bond quality was evaluated using a tensile test on structured dies. The effect of oxygen-based pre-treatments of the nitride surface on the bond quality has been evaluated. Bond strengths up to 35 Nrmm2 and yields up to 100% were obtained....

  15. Anodization of Copper in Chloride Media

    Science.gov (United States)

    1994-01-31

    in various media. In chloride-containing solution, seawater for example, the cuprous species CuCI and CuCl2" are major products of copper anodization...assumption was used in these determinations, which rendered only the foot of the voltammetric wave useful for calculating 132, and the formation of CuCI was...time-independent, and refers to steady-state currents at given potentials. In the present case of the formation of CuCI and CuCl2 , we are interested in

  16. Solid state bistable power switch

    Science.gov (United States)

    Bartko, J.; Shulman, H.

    1970-01-01

    Tin and copper provide high current and switching time capabilities for high-current resettable fuses. They show the best performance for trip current and degree of reliability, and have low coefficients of thermal expansion.

  17. Electron collisions in gas switches

    International Nuclear Information System (INIS)

    Christophorou, L.G.

    1989-01-01

    Many technologies rely on the conduction/insulation properties of gaseous matter for their successful operation. Many others (e.g., pulsed power technologies) rely on the rapid change (switching or modulation) of the properties of gaseous matter from an insulator to a conductor and vice versa. Studies of electron collision processes in gases aided the development of pulsed power gas switches, and in this paper we shall briefly illustrate the kind of knowledge on electron collision processes which is needed to optimize the performance of such switching devices. To this end, we shall refer to three types of gas switches: spark gap closing, self-sustained diffuse discharge closing, and externally-sustained diffuse discharge opening. 24 refs., 15 figs., 2 tabs

  18. Wide Bandgap Extrinsic Photoconductive Switches

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, James S. [State Univ. of New York (SUNY), Plattsburgh, NY (United States); Univ. of California, Davis, CA (United States)

    2012-01-20

    Photoconductive semiconductor switches (PCSS) have been investigated since the late 1970s. Some devices have been developed that withstand tens of kilovolts and others that switch hundreds of amperes. However, no single device has been developed that can reliably withstand both high voltage and switch high current. Yet, photoconductive switches still hold the promise of reliable high voltage and high current operation with subnanosecond risetimes. Particularly since good quality, bulk, single crystal, wide bandgap semiconductor materials have recently become available. In this chapter we will review the basic operation of PCSS devices, status of PCSS devices and properties of the wide bandgap semiconductors 4H-SiC, 6H-SiC and 2H-GaN.

  19. A Piezoelectric Cryogenic Heat Switch

    Science.gov (United States)

    Jahromi, Amir E.; Sullivan, Dan F.

    2014-01-01

    We have measured the thermal conductance of a mechanical heat switch actuated by a piezoelectric positioner, the PZHS (PieZo electric Heat Switch), at cryogenic temperatures. The thermal conductance of the PZHS was measured between 4 K and 10 K, and on/off conductance ratios greater than 100 were achieved when the positioner applied its maximum force of 8 N. We discuss the advantages of using this system in cryogenic applications, and estimate the ultimate performance of an optimized PZHS.

  20. Chromatic interocular-switch rivalry

    Science.gov (United States)

    Christiansen, Jens H.; D'Antona, Anthony D.; Shevell, Steven K.

    2017-01-01

    Interocular-switch rivalry (also known as stimulus rivalry) is a kind of binocular rivalry in which two rivalrous images are swapped between the eyes several times a second. The result is stable periods of one image and then the other, with stable intervals that span many eye swaps (Logothetis, Leopold, & Sheinberg, 1996). Previous work used this close kin of binocular rivalry with rivalrous forms. Experiments here test whether chromatic interocular-switch rivalry, in which the swapped stimuli differ in only chromaticity, results in slow alternation between two colors. Swapping equiluminant rivalrous chromaticities at 3.75 Hz resulted in slow perceptual color alternation, with one or the other color often continuously visible for two seconds or longer (during which there were 15+ eye swaps). A well-known theory for sustained percepts from interocular-switch rivalry with form is inhibitory competition between binocular neurons driven by monocular neurons with matched orientation tuning in each eye; such binocular neurons would produce a stable response when a given orientation is swapped between the eyes. A similar model can account for the percepts here from chromatic interocular-switch rivalry and is underpinned by the neurophysiological finding that color-preferring binocular neurons are driven by monocular neurons from each eye with well-matched chromatic selectivity (Peirce, Solomon, Forte, & Lennie, 2008). In contrast to chromatic interocular-switch rivalry, luminance interocular-switch rivalry with swapped stimuli that differ in only luminance did not result in slowly alternating percepts of different brightnesses. PMID:28510624

  1. Heterotrophic Anodic Denitrification in Microbial Fuel Cells

    Directory of Open Access Journals (Sweden)

    Jakub Drewnowski

    2016-06-01

    Full Text Available Nowadays, pollution caused by energy production systems is a major environmental concern. Therefore, the development of sustainable energy sources is required. Amongst others, the microbial fuel cell (MFC seems to be a possible solution because it can produce clean energy at the same time that waste is stabilized. Unfortunately, mainly due to industrial discharges, the wastes could contain nitrates, or nitrates precursors such ammonia, which could lead to lower performance in terms of electricity production. In this work, the feasibility of coupling anodic denitrification process with electricity production in MFC and the effect of the nitrates over the MFC performance were studied. During the experiments, it was observed that the culture developed in the anodic chamber of the MFC presented a significant amount of denitrificative microorganisms. The MFC developed was able to denitrify up to 4 ppm, without affecting the current density exerted, of about 1 mA/cm2. Regarding the denitrification process, it must be highlighted that the maximum denitrification rate achieved with the culture was about 60 mg·NO3−·L−1·h−1. Based on these results, it can be stated that it is possible to remove nitrates and to produce energy, without negatively affecting the electrical performance, when the nitrate concentration is low.

  2. Alternative Anode Reaction for Copper Electrowinning

    Energy Technology Data Exchange (ETDEWEB)

    2005-07-01

    This report describes a project funded by the Department of Energy, with additional funding from Bechtel National, to develop a copper electrowinning process with lower costs and lower emissions than the current process. This new process also includes more energy efficient production by using catalytic-surfaced anodes and a different electrochemical couple in the electrolyte, providing an alternative oxidation reaction that requires up to 50% less energy than is currently required to electrowin the same quantity of copper. This alternative anode reaction, which oxidizes ferric ions to ferrous, with subsequent reduction back to ferric using sulfur dioxide, was demonstrated to be technically and operationally feasible. However, pure sulfur dioxide was determined to be prohibitively expensive and use of a sulfur burner, producing 12% SO{sub 2}, was deemed a viable alternative. This alternate, sulfur-burning process requires a sulfur burner, waste heat boiler, quench tower, and reaction towers. The electrolyte containing absorbed SO{sub 2} passes through activated carbon to regenerate the ferrous ion. Because this reaction produces sulfuric acid, excess acid removal by ion exchange is necessary and produces a low concentration acid suitable for leaching oxide copper minerals. If sulfide minerals are to be leached or the acid unneeded on site, hydrogen was demonstrated to be a potential reductant. Preliminary economics indicate that the process would only be viable if significant credits could be realized for electrical power produced by the sulfur burner and for acid if used for leaching of oxidized copper minerals on site.

  3. A sealed-off double-gap pseudospark switch and its performance analysis

    Science.gov (United States)

    Lamba, R. P.; Pal, U. N.; Meena, B. L.; Prakash, R.

    2018-03-01

    This paper reports the development of a sealed-off double-gap pseudospark switch and its performance analysis. The modular pseudospark geometry has two gaps that are separated by a cavity drift space region. It utilizes a single ferroelectric trigger unit in a hollow cathode region of the first gap to initiate the discharge for rapid breakdown of both the gaps. The switch has been pinched for deuterium gas and a gas reservoir has been used for maintaining optimum gas pressure in the sealed-off device. The switch design has been analyzed for higher hold-off voltage with high charge transfer capability at higher repetition rates. The developed switch holds a 50 kV voltage in vacuum, and 40 kV during gas discharge at optimum gas pressure with a peak anode current of 8 kA and pulse duration of 1.3 μs while it is operated with a resistive load of 2.9 Ω. The switch has been tested using a constant current charging power supply for pulse repetition frequency up to 50 Hz at different voltages and peak currents corresponding to 200 nF energy storage capacitors. Its performance has been analyzed in terms of pulse parameters including hold-off voltage, jitter, fall time, rise time, peak current and delay time to qualify the design.

  4. Optimal Conditions for Fast Charging and Long Cycling Stability of Silicon Microwire Anodes for Lithium Ion Batteries, and Comparison with the Performance of Other Si Anode Concepts

    OpenAIRE

    Enrique Quiroga-González; Jürgen Carstensen; Helmut Föll

    2013-01-01

    Cycling tests under various conditions have been performed for lithium ion battery anodes made from free-standing silicon microwires embedded at one end in a copper current collector. Optimum charging/discharging conditions have been found for which the anode shows negligible fading (< 0.001%) over 80 cycles; an outstanding result for this kind of anodes. Several performance parameters of the anode have been compared to the ones of other Si anode concepts, showing that especially the capacity...

  5. Coating for lithium anode, thionyl chloride active cathode electrochemical cell

    Energy Technology Data Exchange (ETDEWEB)

    Catanzarite, V.O.

    1983-01-04

    Electrochemical power cells having a cathode current collector, a combination liquid active cathode depolarizer electrolyte solvent and an anode that forms surface compounds when in intimate contact with the liquid cathode are enhanced by the addition of a passivation limiting film contiguous to said anode. The passivating film is a member of the cyanoacrilate family of organic compounds.

  6. Coating for lithium anode, thionyl chloride active cathode electrochemical cell

    Energy Technology Data Exchange (ETDEWEB)

    Catanzarite, V.O.

    1981-10-20

    Electrochemical power cells having a cathode current collector, a combination liquid active cathode depolarizer electrolyte solvent and an anode that forms surface compounds when in intimate contact with the liquid cathode are enhanced by the addition of a passivation limiting film contiguous to said anode. The passivating film is a member of the cyanoacrilate family of organic compounds.

  7. Application of multi-walled carbon nanotubes to enhance anodic ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-12-15

    Dec 15, 2009 ... Nambiar et al. 6929. Figure 1. The setup of the H-type microbial fuel cell system used. A: anode chamber; B: proton exchange membrane junction; C: cathode chamber; D: resistor on the external circuit; length of the anode-cathode chambers connector: 200 mm; inner diameter of the connector tube: 14 mm.

  8. Battery, especially for portable devices, has an anode containing silicon

    NARCIS (Netherlands)

    Kan, S.Y.

    2002-01-01

    The anode (2) contains silicon. A battery with a silicon-containing anode is claimed. An Independent claim is also included for a method used to make the battery, comprising the doping of a silicon substrate (1) with charge capacity-increasing material (preferably boron, phosphorous or arsenic),

  9. Formation of complex anodic films on porous alumina matrices

    Indian Academy of Sciences (India)

    The kinetics of growth of complex anodic alumina films was investigated. These films were formed by filling porous oxide films (matrices) having deep pores. The porous films (matrices) were obtained voltastatically in (COOH)2 aqueous solution under various voltages. The filling was done by re-anodization in an electrolyte ...

  10. Anodic dissolution of alloys during electrochemical dimensional machining of parts

    International Nuclear Information System (INIS)

    Davydov, A.D.

    1980-01-01

    Analysis of the main regularities of anodic dissolution of alloys at current high densities, which is necessary for the explanation and prediction of the results of electrochemical dimensional machining of parts, is carried out. Examples when chemical composition produces the determining effect upon anodic behaviour and electrochemical treatment of the alloys are analyzed

  11. DMFC anode polarization: Experimental analysis and model validation

    Science.gov (United States)

    Casalegno, A.; Marchesi, R.

    Anode two-phase flow has an important influence on DMFC performance and methanol crossover. In order to elucidate two-phase flow influence on anode performance, in this work, anode polarization is investigated combining experimental and modelling approach. A systematic experimental analysis of operating conditions influence on anode polarization is presented. Hysteresis due to operating condition is observed; experimental results suggest that it arises from methanol accumulation and has to be considered in evaluating DMFC performances and measurements reproducibility. A model of DMFC anode polarization is presented and utilised as tool to investigate anode two-phase flow. The proposed analysis permits one to produce a confident interpretation of the main involved phenomena. In particular, it confirms that methanol electro-oxidation kinetics is weakly dependent on methanol concentration and that methanol transport in gas phase produces an important contribution in anode feeding. Moreover, it emphasises the possibility to optimise anode flow rate in order to improve DMFC performance and reduce methanol crossover.

  12. Plasmonic properties of gold-coated nanoporous anodic alumina ...

    Indian Academy of Sciences (India)

    Abstract. Anodization of aluminium surfaces containing linearly oriented scratches leads to the formation of nanoporous anodic alumina (NAA) with the nanopores arranged preferentially along the scratch marks. NAA, when coated with a thin gold film, support plasmonic resonances. Dark-field spectroscopy revealed that ...

  13. Formation of complex anodic films on porous alumina matrices

    Indian Academy of Sciences (India)

    Unknown

    follow the metal surface profile. The porous films are formed in electrolytes dissolving the ... investigated during anodization of different valve metals including Al (Andreeva and Ikonopisov 1970). The vali- .... age (Uf = 400 V) in order to finish the re-anodization just before reaching the breakdown voltage. From the kinetic ...

  14. Electrochemical oxidation of syngas on nickel and ceria anodes

    NARCIS (Netherlands)

    Tabish, A.N.; Patel, H.C.; Purushothaman Vellayani, A.

    2017-01-01

    Fuel flexibility of solid oxide fuel cells enables the use of low cost and practical fuels like syngas. Understanding of the oxidation kinetics with syngas is essential for proper selection of anode material and its design optimization. Using nickel and ceria pattern anodes, we study the

  15. Anodic oxide growth on Zr in neutral aqueous solution

    Indian Academy of Sciences (India)

    Abstract. Anodization and subsequent cathodic reactions on a thin-film sample of Zr were studied with in-situ neutron reflectometry (NR) and electrochemical impedance spec- troscopy (EIS). The NR results during anodization showed the originally 485 Å thick Zr film generally behaved similar to a bulk electrode in neutral ...

  16. Unique Reduced Graphene Oxide as Efficient Anode Material in Li ...

    Indian Academy of Sciences (India)

    19

    SRGO) was explicated as anode material in ... motivation behind testing SRGO as anode material in LIB is owing to its previously reported characteristics [1-3] like high ... Cycling performance of SRGO is shown in Fig. 2 which clearly indicates that ...

  17. Application of multi-walled carbon nanotubes to enhance anodic ...

    African Journals Online (AJOL)

    The effect of multi-walled carbon nanotube (MWCNT) modification of anodes and the optimisation of relevant parameters thereof for application in an Enterobacter cloacae microbial fuel cell were examined. The H – type microbial fuel cells were used for the fundamental studies, with a carbon sheet as a control anode and ...

  18. Cathode Dependence of Liquid-Alloy Na-K Anodes.

    Science.gov (United States)

    Xue, Leigang; Gao, Hongcai; Li, Yutao; Goodenough, John B

    2018-03-07

    Alkali ions can be plated dendrite-free into a liquid alkali-metal anode. Commercialized Na-S battery technology operates above 300 °C. A low-cost Na-K alloy is liquid at 25 °C from 9.2 to 58.2 wt% of sodium; sodium and/or potassium can be plated dendrite-free in the liquid range at room temperature. The co-existence of two alkali metals in an anode raises a question: whether the liquid Na-K alloy acts as a Na or a K anode. Here we show the alkali-metal that is stripped from the liquid Na-K anode is dependent on the preference of the cathode host. It acts as the anode of a sodium rechargeable cell if the cathode host structure selectively accepts only Na + ions; as the anode of a potassium rechargeable cell if the cathode accepts K + ions in preference to Na + ions. This dual-anode behavior means the liquid Na-K alkali-alloy can be applied as a dendrite-free anode in Na-metal batteries as well as K-metal batteries.

  19. Fundamental Investigation of Silicon Anode in Lithium-Ion Cells

    Science.gov (United States)

    Wu, James J.; Bennett, William R.

    2012-01-01

    Silicon is a promising and attractive anode material to replace graphite for high capacity lithium ion cells since its theoretical capacity is 10 times of graphite and it is an abundant element on Earth. However, there are challenges associated with using silicon as Li-ion anode due to the significant first cycle irreversible capacity loss and subsequent rapid capacity fade during cycling. Understanding solid electrolyte interphase (SEI) formation along with the lithium ion insertion/de-insertion kinetics in silicon anodes will provide greater insight into overcoming these issues, thereby lead to better cycle performance. In this paper, cyclic voltammetry and electrochemical impedance spectroscopy are used to build a fundamental understanding of silicon anodes. The results show that it is difficult to form the SEI film on the surface of a Si anode during the first cycle; the lithium ion insertion and de-insertion kinetics for Si are sluggish, and the cell internal resistance changes with the state of lithiation after electrochemical cycling. These results are compared with those for extensively studied graphite anodes. The understanding gained from this study will help to design better Si anodes, and the combination of cyclic voltammetry with impedance spectroscopy provides a useful tool to evaluate the effectiveness of the design modifications on the Si anode performance.

  20. Magnetic-fluid-based smart centrifugal switch

    CERN Document Server

    Bhatt, R P

    2002-01-01

    A new type of centrifugal switch, which we call 'smart centrifugal switch' is designed and developed utilizing the novel properties of magnetic fluid. No mechanical movement is involved in the sensing and switching operations of this centrifugal switch and both these operations are achieved in a smart way. The performance of the switch is studied. This switch has several important advantages over conventional centrifugal switches like smart and non-contact type operation, sparkless and hence explosion proof working and inertia-less simple structure.

  1. Fluctuation-induced switching and the switching path distribution.

    Science.gov (United States)

    Dykman, Mark

    2009-03-01

    Fluctuation-induced switching is at the root of diverse phenomena currently studied in Josephson junctions, nano-mechanical systems, nano-magnets, and optically trapped atoms. In a fluctuation leading to switching the system must overcome an effective barrier, making switching events rare, for low fluctuation intensity. We will provide an overview of the methods of finding the switching barrier for systems away from thermal equilibrium. Generic features of the barrier, such as scaling with the system parameters, will be discussed. We will also discuss the motion of the system in switching and the ways of controlling it. Two major classes of systems will be considered: dynamical systems, where fluctuations are induced by noise, and birth-death systems. Even though the motion during switching is random, the paths followed in switching form a narrow tube in phase space of the system centered at the most probable path. The paths distribution is generally Gaussian and has specific features, which have been seen in the experiment [1]. Finding the most probable path itself can be reduced to solving a problem of Hamiltonian dynamics of an auxiliary noise-free system. The solution also gives the switching barrier. The barrier can be found explicitly close to parameter values where the number of stable states of the system changes and the dynamics is controlled by a slow variable. The scaling of the barrier height depends on the type of the corresponding bifurcation. We show that, both for birth-death and for Gaussian noise driven systems, the presence of even weak non-Gaussian noise can strongly modify the switching rate. The effect is described in a simple explicit form [2,3]. Weak deviations of the noise statistics from Gaussian can be sensitively detected using balanced dynamical bridge, where this deviation makes the populations of coexisting stable states different from each other; a realization of such a bridge will be discussed. We will also discuss the sharp

  2. Interfacial chemistry of zinc anodes for reinforced concrete structures

    Energy Technology Data Exchange (ETDEWEB)

    Covino, B.S. Jr.; Bullard, S.J.; Cramer, S.D.; Holcomb, G.R. [Dept. of Energy, Albany, OR (United States). Albany Research Center; McGill, G.E.; Cryer, C.B. [Oregon Dept. of Transportation, Salem, OR (United States); Stoneman, A. [International Lead Zinc Research Organization, Research Triangle Park, NC (United States); Carter, R.R. [California Dept. of Transportation, Sacramento, CA (United States)

    1997-12-01

    Thermally-sprayed zinc anodes are used in both galvanic and impressed current cathodic protection systems for reinforced concrete structures. The Albany Research Center, in collaboration with the Oregon Department of Transportation, has been studying the effect of electrochemical aging on the bond strength of zinc anodes for bridge cathodic protection systems. Changes in anode bond strength and other anode properties can be explained by the chemistry of the zinc-concrete interface. The chemistry of the zinc-concrete interface in laboratory electrochemical aging studies is compared with that of several bridges with thermal-sprayed zinc anodes and which have been in service for 5 to 10 years using both galvanic and impressed current cathodic protection systems. The bridges are the Cape Creek Bridge on the Oregon coast and the East Camino Undercrossing near Placerville, CA. Also reported are interfacial chemistry results for galvanized steel rebar from the 48 year old Longbird Bridge in Bermuda.

  3. Analysis and design of double-anode magnetron injection gun

    International Nuclear Information System (INIS)

    Yang Tie; Niu Xinjian; Liu Yinghui

    2013-01-01

    Based on electro-optical theory and adiabatic compression theory, a double-anode magnetic injection gun for TE 34,19 , 170 GHz gyrotron was analyzed and designed with EGUN software. Concerning with the factors such as positions of anode and magnetic field distance between anodes, we obtained the result that the velocity ratio of electron beam approximated 1.3, and the velocity spread was under 3%. Furthermore, we found that electron beam was sensitive with these factors, such as that the velocity ratio decreased when the distance between anodes increased, while the velocity spread decreased first and then increased. The double-anode magnetic injection gun is employed in the experiments of gyrotron. (authors)

  4. Growth of anatase titanium dioxide nanotubes via anodization

    Directory of Open Access Journals (Sweden)

    Ed Adrian Dilla

    2012-06-01

    Full Text Available In this work, titanium dioxide nanotubes were grown via anodization of sputtered titanium thin films using different anodization parameters in order to formulate a method of producing long anatase titanium dioxide nanotubes intended for solar cell applications. The morphological features of the nanotubes grown via anodization were explored using a Philips XL30 Field Emission Scanning Electron Microscope. Furthermore, the grown nanotubes were also subjected to X-ray diffraction and Raman spectroscopy in order to investigate the effect of the predominant crystal orientation of the parent titanium thin film on the crystal phase of the nanotubes. After optimizing the anodization parameters, nanotubes with anatase TiO2 crystal phase and tube length more than 2 microns was produced from parent titanium thin films with predominant Ti(010 crystal orientation and using ammonium fluoride in ethylene glycol as an electrolyte with a working voltage equal to 60V during 1-hour anodization runs.

  5. Recovery of plutonium from electrorefining anode heels at Savannah River

    International Nuclear Information System (INIS)

    Gray, J.H.; Gray, L.W.; Karraker, D.G.

    1987-03-01

    In a joint effort, the Savannah River Laboratory (SRL), Savannah River Plant (SRP), and the Rocky Flats Plant (RFP) have developed two processes to recover plutonium from electrorefining anode heel residues. Aqueous dissolution of anode heel metal was demonstrated at SRL on a laboratory scale and on a larger pilot scale using either sulfamic acid or nitric acid-hydrazine-fluoride solutions. This direct anode heel metal dissolution requires the use of a geometrically favorable dissolver. The second process developed involves first diluting the plutonium in the anode heel residues by alloying with aluminum. The alloyed anode heel plutonium can then be dissolved using a nitric acid-fluoride-mercury(II) solution in large non-geometrically favorable equipment where nuclear safety is ensured by concentration control

  6. Natural gas anodes for aluminium electrolysis in molten fluorides.

    Science.gov (United States)

    Haarberg, Geir Martin; Khalaghi, Babak; Mokkelbost, Tommy

    2016-08-15

    Industrial primary production of aluminium has been developed and improved over more than 100 years. The molten salt electrolysis process is still suffering from low energy efficiency and considerable emissions of greenhouse gases (CO2 and PFC). A new concept has been suggested where methane is supplied through the anode so that the CO2 emissions may be reduced significantly, the PFC emissions may be eliminated and the energy consumption may decrease significantly. Porous carbon anodes made from different graphite grades were studied in controlled laboratory experiments. The anode potential, the anode carbon consumption and the level of HF gas above the electrolyte were measured during electrolysis. In some cases it was found that the methane oxidation was effectively participating in the anode process.

  7. A Switch Is Not a Switch: Syntactically-Driven Bilingual Language Control

    Science.gov (United States)

    Gollan, Tamar H.; Goldrick, Matthew

    2018-01-01

    The current study investigated the possibility that language switches could be relatively automatically triggered by context. "Single-word switches," in which bilinguals switched languages on a single word in midsentence and then immediately switched back, were contrasted with more complete "whole-language switches," in which…

  8. Switching Activity Estimation of CIC Filter Integrators

    OpenAIRE

    Abbas, Muhammad; Gustafsson, Oscar

    2010-01-01

    In this work, a method for estimation of the switching activity in integrators is presented. To achieve low power, it is always necessary to develop accurate and efficient methods to estimate the switching activity. The switching activities are then used to estimate the power consumption. In our work, the switching activity is first estimated for the general purpose integrators and then it is extended for the estimation of switching activity in cascaded integrators in CIC filters. ©2010 I...

  9. Principles of broadband switching and networking

    CERN Document Server

    Liew, Soung C

    2010-01-01

    An authoritative introduction to the roles of switching and transmission in broadband integrated services networks Principles of Broadband Switching and Networking explains the design and analysis of switch architectures suitable for broadband integrated services networks, emphasizing packet-switched interconnection networks with distributed routing algorithms. The text examines the mathematical properties of these networks, rather than specific implementation technologies. Although the pedagogical explanations in this book are in the context of switches, many of the fundamenta

  10. Electrochemical degradation of bisphenol A on different anodes.

    Science.gov (United States)

    Cui, Yu-hong; Li, Xiao-yan; Chen, Guohua

    2009-04-01

    Laboratory experiments were carried out on the kinetics, pathways and mechanisms of electrochemical (EC) degradation of bisphenol A (BPA) on four types of anodes, Ti/boron-doped diamond (BDD), Ti/Sb-SnO(2), Ti/RuO(2) and Pt. There were considerable differences among the anodes in their effectiveness and performance of BPA electrolysis. BPA was readily destructed at the Ti/Sb-SnO(2) and Ti/BDD anodes, the Pt anode had a moderate ability to remove BPA, and the Ti/RuO(2) anode was incapable of effectively oxidising BPA. The intermediate products of EC degradation of BPA were detected and quantified by high-performance liquid chromatography (HPLC), and a general BPA degradation pathway was proposed based on the analytical results. It was suggested that OH radicals produced by water electrolysis attacked BPA to form hydroxylated BPA derivatives that were then transformed into one-ring aromatic compounds. These compounds underwent ring breakage, which led to the formation of aliphatic acids that were eventually mineralised by electrolysis to CO(2). Compared to the Pt and Ti/RuO(2) anodes, the Ti/Sb-SnO(2) and Ti/BDD anodes were found to have higher oxygen evolution potentials and higher anodic potentials for BPA electrolysis under the same current condition. However, the stability and durability of the Ti/Sb-SnO(2) anode still needs to be greatly improved for actual application. In comparison, with its high durability and good reactivity for organic oxidation, the Ti/BDD anode appears to be the more promising one for the effective EC treatment of BPA and similar endocrine disrupting chemical (EDC) pollutants.

  11. Tests of a tight scintillator assembly for a sheath failure detector

    International Nuclear Information System (INIS)

    Vasnier, F.

    1968-01-01

    This report first recalls that fission product detectors operating under CO 2 pressure at room temperature are equipped with plastic scintillators which are directly in contact with CO 2 to perform a measurement of the β radiation of collected Rb and Cs atoms, and that defects such as cracks and dimensional variations appeared in these scintillators. As some works showed the influence of CO 2 absorption by plastic scintillators, and the negative influence of oil vapours within the gas on these defects, a tight protection has been proposed for the scintillators by means a thin metal sheath, in order to reduce the energy loss of the β radiation. The author reports tests performed on a prototype to measure the sensitivity decrease due to the β absorption by the stainless steel sheath with respect to a normal scintillator assembly, as well as the change of the signal-to-noise ratio [fr

  12. Shear flow instability in a partially-ionized plasma sheath around a fast-moving vehicle

    International Nuclear Information System (INIS)

    Sotnikov, V. I.; Mudaliar, S.; Genoni, T. C.; Rose, D. V.; Oliver, B. V.; Mehlhorn, T. A.

    2011-01-01

    The stability of ion acoustic waves in a sheared-flow, partially-ionized compressible plasma sheath around a fast-moving vehicle in the upper atmosphere, is described and evaluated for different flow profiles. In a compressible plasma with shear flow, instability occurs for any velocity profile, not just for profiles with an inflection point. A second-order differential equation for the electrostatic potential of excited ion acoustic waves in the presence of electron and ion collisions with neutrals is derived and solved numerically using a shooting method with boundary conditions appropriate for a finite thickness sheath in contact with the vehicle. We consider three different velocity flow profiles and find that in all cases that neutral collisions can completely suppress the instability.

  13. Estimation of the reduction of sputtering for fusion grade materials after disappearance of the Debye sheath

    Science.gov (United States)

    Adhikari, S.; Moulick, R.; Goswami, K. S.

    2018-02-01

    The effect of grazing angle on a solid surface (divertor) erosion due to ion sputtering is studied by 1D-3V fluid approach. For an oblique magnetic field, there exists a region in front of the solid surface called Chodura sheath (CS). It is assumed that the CS is additive to the Debye sheath (DS). For a certain value of the grazing angle, it has been observed that the DS vanishes and the entire potential drop occurs across the CS. This new analysis of the event provides some facts of pragmatic importance in improving the solutions of edge impurity codes. Important factors, such as ion energy, impact angle for physical sputtering are highlighted. The dependence of these two parameters on the grazing angle is also investigated in detail.

  14. Dural ectasia of the optic nerve sheath: is it always benign?

    Directory of Open Access Journals (Sweden)

    Berker Bakbak

    2009-11-01

    Full Text Available Berker Bakbak1, Hava Dönmez2, Tülay Kansu3, Hayyam Kiratli41Hacettepe University Institute of Neurological Sciences and Psychiatry, Neuro-ophthalmology Unit, Ankara, Turkey; 2Diskapi Yildirim Beyazid Education and Research Hospital Neurology Clinic, Ankara, Turkey; 3Hacettepe University Medical Faculty, Department of Neurology, Neuro-Ophthalmology Unit, Ankara, Turkey; 4Hacettepe University Medical Faculty, Department of Ophthalmology, Ocular Oncology Unit, Ankara, TurkeyAbstract: A 36-year-old woman with a 3-month history of progressive visual loss had papilledema, dilatation of the optic nerve sheaths and normal cerebrospinal fluid pressures. She was diagnosed as dural ectasia of the optic nerve sheaths and surgical decompression was performed. In this case report, severe visual loss is described as a serious complication of this rare disease and the importance of early surgical intervention is emphasized.Keywords: optic nerve, dural ectasia, meningocele

  15. Doppler spectroscopic measurements of sheath ion velocities in radio-frequency plasmas

    International Nuclear Information System (INIS)

    Woodcock, B.K.; Busby, J.R.; Freegarde, T.G.; Hancock, G.

    1997-01-01

    We have measured the distributions of N 2 + ion velocity components parallel and perpendicular to the electrode in the sheath of a radio-frequency nitrogen reactive ion etching discharge, using pulsed laser-induced fluorescence. Parallel to the electrode, the ions have throughout a thermal distribution that is found to be consistent with the rotational temperature of 355 K. In the perpendicular direction, we see clearly the acceleration of the ions towards the electrode, and our results agree well with theoretical predictions although an unexpected peak of unaccelerated ions persists. We have also determined the absolute ion concentrations in the sheath, which we have calibrated by analyzing the decay in laser-induced fluorescence in the plasma bulk after discharge extinction. At 20 mTorr, the bulk concentration of 1.0x10 10 cm -3 falls to around 2x10 8 cm -3 at 2 mm from the electrode. copyright 1997 American Institute of Physics

  16. Invited paper: non-equilibrium kinetics and gas heating in the cathode sheath

    International Nuclear Information System (INIS)

    Long, W.H.

    1983-01-01

    The cathode sheath is a region of steep gradients in electric field and gas density. Electrons leaving the cathode surface do not in general reach equilibrium with the local electric field until well into the negative glow. Previous theories, which assume local equilibrium, have demonstrated fair agreement with experimental measurements of normal cathode fall voltage and current density, but do not reproduce the basic structure of the cathode region observed at low pressure. In the present work, the local electron energy distribution is determined from a numerical solution of the Boltzmann equation in the presence of strong field and density gradients. Self-consistent coupling to the electric field, ion kinetics and gas dynamics is included. In subsonic flows, it is found that the sheath and boundary layer can be treated independently

  17. Study on plasma sheath and plasma transport properties in the azimuthator

    Science.gov (United States)

    Zhenyu, WANG; Binhao, JIANG; N, A. STROKIN; A, N. STUPIN

    2018-04-01

    A physical model of transport in an azimuthator channel with the sheath effect resulting from the interaction between the plasma and insulation wall is established in this paper. Particle in cell simulation is carried out by the model and results show that, besides the transport due to classical and Bohm diffusions, the sheath effect can significantly influences the transport in the channel. As a result, the ion density is larger than the electron density at the exit of azimuthator, and the non-neutral plasma jet is divergent, which is unfavorable for mass separation. Then, in order to improve performance of the azimuthator, a cathode is designed to emit electrons. Experiment results have demonstrated that the auxiliary cathode can obviously compensate the space charge in the plasma.

  18. Plasma sheath physics and dose uniformity in enhanced glow discharge plasma immersion ion implantation and deposition

    International Nuclear Information System (INIS)

    Li Liuhe; Li Jianhui; Kwok, Dixon T. K.; Chu, Paul K.; Wang Zhuo

    2009-01-01

    Based on the multiple-grid particle-in-cell code, an advanced simulation model is established to study the sheath physics and dose uniformity along the sample stage in order to provide the theoretical basis for further improvement of enhanced glow discharge plasma immersion ion implantation and deposition. At t=7.0 μs, the expansion of the sheath in the horizontal direction is hindered by the dielectric cage. The electron focusing effect is demonstrated by this model. Most of the ions at the inside wall of the cage are implanted into the edge of the sample stage and a relatively uniform ion fluence distribution with a large peak is observed at the end. Compared to the results obtained from the previous model, a higher implant fluence and larger area of uniformity are disclosed.

  19. Fastener Demands for Sheathing-Braced Cold-Formed Steel Stud Gravity Walls

    Directory of Open Access Journals (Sweden)

    Luiz Carlos M. Vieira Junior

    Full Text Available Abstract We explore, in this paper, the demands and behavior on fasteners supplying sheathing-based bracing of gravity loaded cold-formed studs and wall assemblies. The studies are carried out by shell finite element (FE models, which are compared to analytical solutions and previously completed laboratory tests conducted by the authors. The connection between the sheathing and the stud should be able to develop enough resistance to restrain global buckling of the studs; therefore, special attention has to be given to the demands on these connections for design. Local buckling and stress concentrations may damage some connections and redistribution of forces should be ensured. Classical practice for determining fastener demand - i.e., the 2% rule - may be deficient. An analytical method developed for determining fastener demand is compared to the FE models presented in this paper; the analytical method results in a reasonable prediction of the fastener forces in wall studs.

  20. An unusual case of cycticercosis of the tendon sheath of the tendoachilles.

    Directory of Open Access Journals (Sweden)

    Sharat Agarwal

    2010-04-01

    Full Text Available Cysticercosis is an infection by the larval stage (cystcercus cellulosae of the cestode, Taenia Solium (pork tape worm, especially in those individuals who live in the endemic areas. After gaining entry into the body, the larvae become encysted and may lie in subcutaneous tissue, striated muscle, the vitreous humor, or other tissues. We report an unusual case of cysticercosis of the the tendon sheath of the tendoachilles that presented as a swelling of the tendoachilles. Upon Fine Needle Aspiration and Cytology (FNAC that were conducted preoperatively, the possibility of villonodular synovitis was identified. However, the cysticercosis diagnosis was confirmed later after an excisional biopsy was performed. We could find no reports in the literature concerning an occurrence of cysticercosis in the tendon sheath of tendoachilles.