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Sample records for ablative capillary discharge

  1. Capillary discharge source

    DOEpatents

    Bender, III, Howard Albert

    2003-11-25

    Debris generation from an EUV electric discharge plasma source device can be significantly reduced or essentially eliminated by encasing the electrodes with dielectric or electrically insulating material so that the electrodes are shielded from the plasma, and additionally by providing a path for the radiation to exit wherein the electrodes are not exposed to the area where the radiation is collected. The device includes: (a) a body, which is made of an electrically insulating material, that defines a capillary bore that has a proximal end and a distal end and that defines at least one radiation exit; (b) a first electrode that defines a first channel that has a first inlet end that is connected to a source of gas and a first outlet end that is in communication with the capillary bore, wherein the first electrode is positioned at the distal end of the capillary bore; (c) a second electrode that defines a second channel that has a second inlet end that is in communication with the capillary bore and an outlet end, wherein the second electrode is positioned at the proximal end of the capillary bore; and (d) a source of electric potential that is connected across the first and second electrodes, wherein radiation generated within the capillary bore is emitted through the at least one radiation exit and wherein the first electrode and second electrode are shielded from the emitted radiation.

  2. Features of spatial distribution of the parameters on the initial section of a supersonic plasma jet, created by pulsed discharge in a capillary with ablative wall

    NASA Astrophysics Data System (ADS)

    Ageev, A. G.; Bityurin, V. A.; Chinnov, V. F.; Efimov, A. V.; Pashchina, A. S.

    2016-11-01

    The results of spectroscopic studies of the initial section of the supersonic plasma jet created by a pulsed discharge in the capillary with the ablative wall are presented. Features of the spatial distribution of the electron density and the intensity of the spectral components, which, in particular, caused by the high electron temperature in the hot central zone, exceeding the “normal” temperature, as well as significant non-isobaricity at the initial section of supersonic jet are revealed. The presence of the molecular components exhibiting their emission properties at the plasma jet periphery permit us to estimate the parameters of the plasma in the spatial domain, where “detached” shock waves of the supersonic jet are created.

  3. Capillary underwater discharges in repetitive pulse regime

    NASA Astrophysics Data System (ADS)

    de Baerdemaeker, F.; Monte, M.; Leys, C.

    2004-03-01

    In this study a capillary underwater discharge, that is sustained with AC (50 Hz) voltages up to 7.5 kV, is investigated. In a capillary discharge scheme, the current is, at some point along its path between two submerged electrodes, flowing through a narrow elongated bore in a dielectric material. When the current density is sufficiently high, local boiling and subsequent vapour breakdown results in the formation of a plasma within this capillary. At the same time the capillary emits an intense jet of vapour bubbles. Time-dependent electrical current, voltage and light emission curves are recorded for discharges in solutions of NaCl in distilled water and reveal different discharge regimes, depending on the conductivity and the excitation voltage, ranging from repetitive microsecond discharge pulses to a quasi-continuous discharge with a glow-like voltage-current characteristic.

  4. Guiding and Ionization Blueshift in Ablative Capillary Waveguide Accelerators

    SciTech Connect

    McGuffey, Chris; Matsuoka, Takeshi; Bulanov, Stepan; Chvykov, Vladimir; Kalintchenko, Galina; Rousseau, Pascal; Yanovsky, Victor; Maksimchuk, Anatoly; Krushelnick, Karl; Levin, Michael; Zigler, Arie

    2009-01-22

    Laser wakefield acceleration (LWFA) in plasmas has been demonstrated with gradients which are orders of magnitude greater than the limit on conventional Radio Frequency accelerators. However, the acceleration length is limited by two factors, the dephasing length and the Rayleigh range of the laser pulse. Dephasing length is the distance in which electrons overtake the laser pulse and can be increased by decreasing plasma density. Alternatively the interaction length can be extended by orders of magnitude by using ablative wall discharge capillary targets, in which a plasma is preformed with a transverse density profile capable of guiding the focused laser. We have demonstrated guiding of high intensity laser pulses from the HERCULES laser over 3 cm for powers up to 35 TW. The quality of the laser spot can be retained and the intensity remains high even at the exit of the capillary. The transmitted laser spectrum shows blueshifting due to field ionization by the laser pulse. This ionization might enhance electron injection at low electron density for LWFA GeV accelerators. The field ionization affects carbon atoms and ions from the ablated capillary, which are not present in hydrogen-filled capillaries. This creates an additional challenge to guiding compared to hydrogen-filled capillaries. However, the setup and materials are easier to come by. The use of these capillary targets may also be of interest to other high intensity laser-plasma interactions requiring long interaction lengths such as high harmonic generation from gases and plasmas, or x-ray lasing in underdense plasmas.

  5. Capillary discharge extreme ultraviolet lasers. [Colorado State Univ. , Ft. Collins

    SciTech Connect

    Rocca, J.J.

    1992-08-01

    The project objective is to explore the generation of soft X-ray laser radiation in a plasma column created by a fast capillary discharge. The proposed capillary lasing scheme offers the potential for compact, simple and efficient soft X-ray laser sources. For this purpose a compact, fast pulse generator which produces 100 kA current pulses with a risetime of 11 ns was constructed. Initial experiments were conducted in evacuated capillaries, in which the plasma is produced by ablation of the capillary walls. The soft X-ray emission from discharges in polyethylene capillary channels was studied to investigate the possibility of amplification in the 3-2 transition of C VI, at {lambda} = 18.2 nm. Time-resolved spectra in which this transition appears anomalously intense with respect to the 4--2 transition of the same ion were obtained. To date, however, this phenomenoa could not be confirmed as gain, as the intensity of the 18.2 nm line has not been observed to increase exponentially as a function of the capillary length. Encouraging results were obtained by fast pulse discharge excitation of capillaries filled with preionized gas. High temperature (Te > 150 eV), small diameter ({approximately}200 {mu}m) plasma columns were efficiently generated. Fast current pulse excitation of a selected low mass density of uniformly preionized material Mag the capillary was observed to detach rapidly the plasma from the capillary walls, and form a plasma channel of a diameter much smaller and significantly hotter than those produced by a similar current pulse in evacuated capillaries of the same size. Discharges in argon-filled capillaries at currents between 20 and 60 kA produced plasmas with ArX-Ar{sub XIV} line emission, and with spectra that are similar to those of plasmas generated by > I MA current implosions in large pulsed power machines. The characteristic of these plasmas approach those necessary for soft X-ray amplification in low Z elements.

  6. EUV radiation from nitrogen capillary discharge

    NASA Astrophysics Data System (ADS)

    Frolov, Oleksandr; Kolacek, Karel; Schmidt, Jiri; Straus, Jaroslav

    2014-08-01

    In the last decade EUV sources attract interest from researchers over the world. One of the main motivations is EUV lithography, which could lead to further miniaturization in electronics. Nitrogen recombination laser at wavelength of 13.4 nm based on capillary discharge Z-pinch configuration could be used in experiments with testing of resolution of photoresist for EUV lithography (close to wavelength of 13.5 nm Si/Mo multilayer mirrors have a high reflectivity at normal incidence angles). In this work, pinching of nitrogen-filled capillary discharge is studied for the development of EUV laser, which is based on recombination pumping scheme. The goal of this study is achieving the required plasma conditions using a capillary discharge Z-pinch apparatus. In experiments with nitrogen, the capillary length was shortened from 232 mm to 90 mm and current quarter-period was changed from 60 ns to 50 ns in contrast with early experiments with Ne-like argon laser. EUV radiation from capillary discharge was registered by X-ray vacuum diode for different pressure, amplitude and duration of pre-pulse and charging voltage of the Marx generator.

  7. SXR optical diagnostics of capillary discharge plasma

    NASA Astrophysics Data System (ADS)

    Pina, L.; Jancarek, A.; Vrbova, M.; Tamas, M.; Blazej, J.; Havlikova, R.; Vrba, P.; Tomassetti, G.; Ritucci, A.

    2006-08-01

    Pinching capillary discharge in nitrogen is investigated for the purpose of development of laser recombination pumping. An apparatus, previously realized for argon capillary laser pumping, was used to understand details of pinching mechanism and emission characteristics for capillary filled by nitrogen. Time dependences of radiation intensities emitted in the wavelength range 1.9 - 2.5 nm and time integrated in the spectral range 10 - 20 nm were measured under various pressures. A computer model is used to describe the pinch dynamics and to estimate the radiation characteristics. EUV reflection grating spectrometer coupled to BI CCD camera and filtered PIN diode were used for time integrated and time resolved spectral measurements respectively. The measured profiles of radiation intensities are compared with the computer simulations of time dependences of selected energy level populations that correspond to the hydrogen- and helium- like ion line emission in the detected spectral range. Complex method for spectral image restoration was developed.

  8. A Model of Ablative Capillary Discharge (Preprint)

    DTIC Science & Technology

    2006-01-04

    currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE (DD-MM-YYYY) 04-01-2006 2. REPORT TYPE Technical......Edwards AFB CA 93524-7048 AFRL-PR-ED-TP-2006-013 12. DISTRIBUTION / AVAILABILITY STATEMENT Approved for public release ; distribution unlimited (AFRL

  9. Plasma Acceleration from RF Discharge in Dielectric Capillary

    SciTech Connect

    A. Dunaevsky; Y. Raitses; N. J. Fisch

    2005-08-09

    Plasma acceleration from rf discharge in dielectric capillary was demonstrated. Observed plasma flow had ion energies of approximately 100 eV and electron energies of approximately 20 eV. The discharge was powered by a MHz-range rf generator and fed by Ar. Experimental results indicate possible validity of assumptions about formation of a potential difference at the open end of the capillary and presence of hot electron fraction in the capillary discharge. Simplicity and small dimensions of the source are attractive for micro-propulsion applications.

  10. Fast plasma discharge capillary design as a high power throughput soft x-ray emission source

    SciTech Connect

    Wyndham, E. S.; Favre, M.; Valdivia, M. P.; Valenzuela, J. C.; Chuaqui, H.; Bhuyan, H.

    2010-09-15

    We present the experimental details and results from a low energy but high repetition rate compact plasma capillary source for extreme ultraviolet and soft x-ray research and applications. Two lengths of capillary are mounted in two versions of a closely related design. The discharge operates in 1.6 and 3.2 mm inner diameter alumina capillaries of lengths 21 and 36 mm. The use of water both as dielectric and as coolant simplifies the compact low inductance design with nanosecond discharge periods. The stored electrical energy of the discharge is approximately 0.5 J and is provided by directly charging the capacitor plates from an inexpensive insulated-gate bipolar transistor in 1 {mu}s or less. We present characteristic argon spectra from plasma between 30 and 300 A as well as temporally resolved x-ray energy fluence in discrete bands on axis. The spectra also allow the level of ablated wall material to be gauged and associated with useful capillary lifetime according to the chosen configuration and energy storage. The connection between the electron beams associated with the transient hollow cathode mechanism, soft x-ray output, capillary geometry, and capillary lifetime is reported. The role of these e-beams and the plasma as measured on-axis is discussed. The relation of the electron temperature and the ionization stages observed is discussed in the context of some model results of ionization in a non-Maxwellian plasma.

  11. Fast plasma discharge capillary design as a high power throughput soft x-ray emission source.

    PubMed

    Wyndham, E S; Favre, M; Valdivia, M P; Valenzuela, J C; Chuaqui, H; Bhuyan, H

    2010-09-01

    We present the experimental details and results from a low energy but high repetition rate compact plasma capillary source for extreme ultraviolet and soft x-ray research and applications. Two lengths of capillary are mounted in two versions of a closely related design. The discharge operates in 1.6 and 3.2 mm inner diameter alumina capillaries of lengths 21 and 36 mm. The use of water both as dielectric and as coolant simplifies the compact low inductance design with nanosecond discharge periods. The stored electrical energy of the discharge is approximately 0.5 J and is provided by directly charging the capacitor plates from an inexpensive insulated-gate bipolar transistor in 1 μs or less. We present characteristic argon spectra from plasma between 30 and 300 Å as well as temporally resolved x-ray energy fluence in discrete bands on axis. The spectra also allow the level of ablated wall material to be gauged and associated with useful capillary lifetime according to the chosen configuration and energy storage. The connection between the electron beams associated with the transient hollow cathode mechanism, soft x-ray output, capillary geometry, and capillary lifetime is reported. The role of these e-beams and the plasma as measured on-axis is discussed. The relation of the electron temperature and the ionization stages observed is discussed in the context of some model results of ionization in a non-Maxwellian plasma.

  12. Demonstration of a high repetition rate capillary discharge waveguide

    SciTech Connect

    Gonsalves, A. J. Pieronek, C.; Daniels, J.; Bulanov, S. S.; Waldron, W. L.; Mittelberger, D. E.; Leemans, W. P.; Liu, F.; Antipov, S.; Butler, J. E.; Bobrova, N. A.; Sasorov, P. V.

    2016-01-21

    A hydrogen-filled capillary discharge waveguide operating at kHz repetition rates is presented for parameters relevant to laser plasma acceleration (LPA). The discharge current pulse was optimized for erosion mitigation with laser guiding experiments and MHD simulation. Heat flow simulations and measurements showed modest temperature rise at the capillary wall due to the average heat load at kHz repetition rates with water-cooled capillaries, which is promising for applications of LPAs such as high average power radiation sources.

  13. Spectroscopic and energetic investigation of capillary discharges devoted to EUV production for new lithography generation

    NASA Astrophysics Data System (ADS)

    Robert, Eric; Blagojevic, Branimir M.; Dussart, Remi; Mohanty, Smruti R.; Idrissi, Moulay M.; Hong, Dunpin; Viladrosa, Raymond; Pouvesle, Jean-Michel; Fleurier, Claude; Cachoncinlle, Christophe

    2001-08-01

    In this work, ablative and gas capillary discharges have been investigated as potential sources for the EUV lithography technology. Carbon and lithium ablative discharge spectroscopy and EUV energy measurements have been performed. Gas (O2, Ne, Ar, Kr and Xe) capillary discharge were powered by fast, nanosecond, high voltage Blumlein-like pulser. Detailed investigation of capillary length and diameter, gas pressure, capacitance and inductance of the electrical driver are documented. The energy density, expressed in J cm-3, appears as a monitoring factor for an efficient production of 13.5 nm radiation band. The measurement and the evaluation of measurement uncertainties lead to the conclusion that the in band, 13.5 nm +/- 0.9 nm, energy radiated by the Xe lamp developed in this work ranges from 0.5 mJ/sr/shot to 20 mJ/sr/shot for a 7 J energy input. Repetition rate investigation of the first prototype have shown operation at 50 Hz in continuous mode and up to 350 Hz in burst mode.

  14. Capillary discharge extreme ultraviolet lasers. Progress report, December 15, 1991--December 14, 1992

    SciTech Connect

    Rocca, J.J.

    1992-08-01

    The project objective is to explore the generation of soft X-ray laser radiation in a plasma column created by a fast capillary discharge. The proposed capillary lasing scheme offers the potential for compact, simple and efficient soft X-ray laser sources. For this purpose a compact, fast pulse generator which produces 100 kA current pulses with a risetime of 11 ns was constructed. Initial experiments were conducted in evacuated capillaries, in which the plasma is produced by ablation of the capillary walls. The soft X-ray emission from discharges in polyethylene capillary channels was studied to investigate the possibility of amplification in the 3-2 transition of C VI, at {lambda} = 18.2 nm. Time-resolved spectra in which this transition appears anomalously intense with respect to the 4--2 transition of the same ion were obtained. To date, however, this phenomenoa could not be confirmed as gain, as the intensity of the 18.2 nm line has not been observed to increase exponentially as a function of the capillary length. Encouraging results were obtained by fast pulse discharge excitation of capillaries filled with preionized gas. High temperature (Te > 150 eV), small diameter ({approximately}200 {mu}m) plasma columns were efficiently generated. Fast current pulse excitation of a selected low mass density of uniformly preionized material Mag the capillary was observed to detach rapidly the plasma from the capillary walls, and form a plasma channel of a diameter much smaller and significantly hotter than those produced by a similar current pulse in evacuated capillaries of the same size. Discharges in argon-filled capillaries at currents between 20 and 60 kA produced plasmas with ArX-Ar{sub XIV} line emission, and with spectra that are similar to those of plasmas generated by > I MA current implosions in large pulsed power machines. The characteristic of these plasmas approach those necessary for soft X-ray amplification in low Z elements.

  15. Optical emission spectroscopy observations of fast pulsed capillary discharge plasmas

    NASA Astrophysics Data System (ADS)

    Avaria, G.; Ruiz, M.; Guzmán, F.; Favre, M.; Wyndham, E. S.; Chuaqui, H.; Bhuyan, H.

    2014-05-01

    We present time resolved optical emission spectroscopic (OES) observations of a low energy, pulsed capillary discharage (PCD). The optical emission from the capillary plasma and plasma jets emitted from the capillary volume was recorded with with a SpectraPro 275 spectrograph, fitted with a MCP gated OMA system, with 15 ns time resolution. The discharge was operated with different gases, including argon, nitrogen, hydrogen and methane, in a repetitive pulsed discharge mode at 10-50 Hz, with, 10-12 kV pulses applied at the cathode side. The time evolution of the electron density was measured using Stark broadening of the Hβ line. Several features of the capillary plasma dynamics, such as ionization growth, wall effects and plasma jet evolution, are inferred from the time evolution of the optical emission.

  16. Radially resolved spectral observations of polyacetal capillary discharge plasmas

    NASA Astrophysics Data System (ADS)

    Morgan, C. A.; Griem, H. R.; Elton, R. C.

    1995-07-01

    The temporal evolution of the radial profile of lithium-like oxygen (OVI or O5+) 3d-4f, 52.0 nm emission from 80 ns rise time, 6-16 kA peak current, pulsed capillary discharges in 1 mm diam, 1 cm long polyacetal capillaries, has been studied. Evidence was seen for a central ``flattening'' in this emission. Extreme-ultraviolet, time-integrated, pinhole transmission grating spectra were taken of discharges at 16 and 23 kA peak currents in 0.5 mm diam, 1 cm long capillaries. Spectra obtained at the higher peak current (23 kA) showed evidence of helium-like (CV or C4+) and/or hydrogen-like carbon (CV or C5+) resonance line emission (4.0 and 3.4 nm wavelength) filling the capillary diameter.

  17. Study on the characteristics of a two gap capillary discharge

    SciTech Connect

    Huang, D.; Yang, L. J. Huo, P.; Ma, J. B.; Ding, W. D.; Wang, W.

    2015-02-15

    The paper presents a new two-gap capillary (TGC) discharge structure. The prominent innovation is the introduction of the middle electrode, which divides the capillary into the trigger gap and the main gap. The discharge circuit of the TGC comprises the trigger circuit and the main circuit. The two circuits are used for the pre-ionization of the trigger gap and providing energy of 450 J for the main gap arc discharging, respectively. When the discharge initiates, the trigger gap is pre-ionized under high voltage pulse produced by trigger circuit, and meanwhile, the weakly ionized plasma is generated. The main circuit then maintains the expansion of the plasma, which is called soft capillary discharge. Afterwards, the main gap is shorted and discharges under a relatively low voltage. With the optimization of the circuit parameter, both the energy deposition ratio in main gap and the degree of plasma ionization are enhanced. The efficiency of the energy deposition is almost twice higher compared with that of the conventional capillary structure. The life performance test indicates that the erosion of the middle electrode and the trigger gap carbonization are the key factors that limit the life performance of the TGC.

  18. A theoretical study of a laser-irradiated capillary discharge

    SciTech Connect

    Petway, L. B.; Back, C. A.; Estabrook, K.; Lee, R. W.; Zigler, A.

    1989-08-15

    A theoretical study of a laser-irradiated capillary discharge is presented. The discharge produces a columnar flow of low-temperature plasma (1 eV) with a density of 10/sup 19/ atoms/cm/sup 3/. This ambient low-temperature plasma is then irradiated by a 1.06-/mu/m Nd glass laser with pulse lengths from 100 ps to 1 ns. The resultant plasma is studied, using hydrodynamic simulations coupled to a detailed kinetics model.

  19. A capillary discharge plasma source of intense VUV radiation

    SciTech Connect

    Sobel'man, Igor I; Shevelko, A P; Yakushev, O F; Knight, L V; Turley, R S

    2003-01-31

    The results of investigation of a capillary discharge plasma, used as a source of intense VUV radiation and soft X-rays, are presented. The plasma was generated during the discharge of low-inductance condensers in a gas-filled ceramic capillary. Intense line radiation was observed in a broad spectral range (30-400 A) in various gases (CO{sub 2}, Ne, Ar, Kr, Xe). The absolute radiation yield for the xenon discharge was {approx}5 mJ (2{pi} sr){sup -1} pulse{sup -1} within a spectral band of width 9 A at 135 A. Such a radiation source can be used for various practical applications, such as EUV projection lithography, microscopy of biological objects in a 'water window', reflectometry, etc. (special issue devoted to the 80th anniversary of academician n g basov's birth)

  20. Femtosecond laser ablation particle introduction to a liquid sampling-atmospheric pressure glow discharge ionization source

    SciTech Connect

    Carado, Anthony J.; Quarles, C. Derrick; Duffin, Andrew M.; Barinaga, Charles J.; Russo, Richard E.; Marcus, R. Kenneth; Eiden, Gregory C.; Koppenaal, David W.

    2012-01-01

    This work describes the use of a compact, liquid sampling – atmospheric pressure glow discharge (LS-APGD) ionization source to ionize metal particles within a laser ablation aerosol. Mass analysis was performed with a Thermo Scientific Exactive Mass Spectrometer which utilizes an orbitrap mass analyzer capable of producing mass resolution exceeding M/ΔM > 160,000. The LS-APGD source generates a low-power plasma between the surface of an electrolytic solution flowing at several µl min-1 through a fused silica capillary and a counter electrode consisting of a stainless steel capillary employed to deliver the laser ablation particles into the plasma. Sample particles of approximately 100 nm were generated with an Applied Spectra femtosecond laser located remotely and transported through 25 meters of polyurethane tubing by means of argon carrier gas. Samples consisted of an oxygen free copper shard, a disk of solder, and a one-cent U.S. coin. Analyte signal onset was readily detectable relative to the background signal produced by the carrier gas alone. The high mass resolution capability of the orbitrap mass spectrometer was demonstrated on the solder sample with resolution exceeding 90,000 for Pb and 160,000 for Cu. In addition, results from a laser ablation depth-profiling experiment of a one cent coin revealed retention of the relative locations of the ~10 µm copper cladding and zinc rich bulk layers.

  1. Experimental Comparison of Capillary Pinching Discharge in Argon and Nitrogen

    NASA Astrophysics Data System (ADS)

    Jancarek, A.; Pina, L.; Vrbova, M.; Tamas, M.; Havlikova, R.; Palinek, S.; Vrba, P.; Kolacek, K.; Schmidt, J.; Strauss, J.

    Experiments with CAPEX-U apparatus were done to more understand the differences between Ar and N active media created during the pinch compression, respectively. Capillary discharge current, X-ray narrow band radiation and EUV spectrum temporal behavior were measured. Results of laboratory experiments for both gas fillings under various currents and initial pressures are shown. Computer simulations show that current quasi-period shortening and higher amplitude is needed.

  2. High-order harmonic generation in a capillary discharge

    DOEpatents

    Rocca, Jorge J.; Kapteyn, Henry C.; Mumane, Margaret M.; Gaudiosi, David; Grisham, Michael E.; Popmintchev, Tenio V.; Reagan, Brendan A.

    2010-06-01

    A pre-ionized medium created by a capillary discharge results in more efficient use of laser energy in high-order harmonic generation (HHG) from ions. It extends the cutoff photon energy, and reduces the distortion of the laser pulse as it propagates down the waveguide. The observed enhancements result from a combination of reduced ionization energy loss and reduced ionization-induced defocusing of the driving laser as well as waveguiding of the driving laser pulse. The discharge plasma also provides a means to spectrally tune the harmonics by tailoring the initial level of ionization of the medium.

  3. Atmospheric pressure arc discharge with ablating graphite anode

    SciTech Connect

    Nemchinsky, V. A.; Raitses, Y.

    2015-05-18

    The anodic carbon arc discharge is used to produce carbon nanoparticles. Recent experiments with the carbon arc at atmospheric pressure helium demonstrated the enhanced ablation rate for narrow graphite anodes resulting in high deposition rates of carbonaceous products on the copper cathode (Fetterman et al 2008 Carbon 46 1322–6). The proposed model explains these results with interconnected steady-state models of the cathode and the anode processes. When considering cathode functioning, the model predicts circulation of the particles in the near-cathode region: evaporation of the cathode material, ionization of evaporated atoms and molecules in the near-cathode plasma, return of the resulting ions to the cathode, surface recombination of ions and electrons followed again by cathode evaporation etc. In the case of the low anode ablation rate, the ion acceleration in the cathode sheath provides the major cathode heating mechanism. In the case of an intensive anode ablation, an additional cathode heating is due to latent fusion heat of the atomic species evaporated from the anode and depositing at the cathode. Using the experimental arc voltage as the only input discharge parameter, the model allows us to calculate the anode ablation rate. A comparison of the results of calculations with the available experimental data shows reasonable agreement.

  4. Time resolved EUV spectra from Zpinching capillary discharge plasma

    NASA Astrophysics Data System (ADS)

    Jancarek, Alexandr; Nevrkla, Michal; Nawaz, Fahad

    2015-09-01

    We developed symmetrically charged driver to obtain high voltage, high current Z-pinching capillary discharge. Plasma is created by up to 70 kA, 29 ns risetime current pulse passing through a 5 mm inner diameter, 224 mm long capillary filled with gas to initial pressure in the range of 1 kPa. Due to the low inductance design of the driver, the pinch is observable directly from the measured current curve. Time-integrated and time-resolved spectra of discharge plasma radiation are recorded together with the capillary current and analyzed. The most encouraging spectra were captured in the wavelength range 8.3 ÷ 14 nm. This spectral region contains nitrogen Balmer series lines including potentially lasing NVII 2 - 3 transition. Spectral lines are identified in the NIST database using the FLY kinetic code. The line of 13.38 nm wavelength, transition NVII 2 - 3, was observed in gated, and also in time-integrated spectra for currents >60 kA. This work has been supported by the Ministry of Education, Youth and Sports of the Czech Republic grants LG13029.

  5. Development of a Specific Impulse Balance for a Pulsed Capillary Discharge (Preprint)

    DTIC Science & Technology

    2008-06-13

    thrust stand [rad/s] I. Introduction A capillary discharge based coaxial , electrothermal pulsed plasma thruster (PPT) is currently under...20-23 July 2008. 14. ABSTRACT A capillary discharge based pulsed plasma thruster is currently under development at the Air Force Research...Edwards AFB, CA 93524 A capillary discharge based pulsed plasma thruster is currently under development at the Air Force Research Laboratory. A

  6. Formation of nanostructures induced by capillary-discharge soft X-ray laser on BaF2 surfaces

    NASA Astrophysics Data System (ADS)

    Zhao, Yongpeng; Cui, Huaiyu; Zhang, Shuqing; Zhang, Wenhong; Li, Wei

    2017-02-01

    BaF2 was ablated by a capillary-discharge pumped soft X-ray laser at 46.9 nm focused by a toroidal mirror at a grazing incidence of 83°. The damaged area, induced by both single and multiple laser pulses, was determined to be covered with fringe-like nanostructures with spacings of approximately 400 nm and mastoid nanostructures with diameters of approximately 600 nm. In this study, we analyze the morphology of the detected damage patterns and discuss the damage mechanism. Results indicate that the depth of the nanostructures varies with different pulse numbers and laser power densities.

  7. Characterization of the Basic Operational Properties of the Capillary Plasma Electrode (CPE) Discharge

    NASA Astrophysics Data System (ADS)

    Lopez, Jose; Zhu, Weidong; Figus, Margaret; Becker, Kurt

    2008-10-01

    Various approaches have been pursued to create stable atmospheric pressure discharges by extending the lifetime of the diffuse phase of the discharge to hundreds of microseconds. Previous research showed that the stability of the diffuse mode is dependent on the frequency (in the kHz range), gas type, power, mode of the excitation, and geometrical confinement. The Capillary Plasma Electrode (CPE) discharge is able to produce stable atmospheric pressure nonequilibrium plasmas. The CPE is similar in design to a barrier-electrode discharge, but has perforated dielectrics. This configuration, aside from exhibiting a diffuse mode of operation, also exhibits the so-called ``capillary jet'' mode, in which the capillaries ``turn on'' and a bright plasma jet emerges from the capillaries. The capillary jets from adjacent capillaries overlap so that the discharge appears uniform when the electrode contains an array of holes. There appears to be a threshold frequency for the capillary jet formation, which is strongly dependent on the L/D ratio of the capillaries, where D is the diameter of a capillary and L its length. This current work explores these modes of operation of the CPE by characterizing the electrical and optical emission properties of this discharge.

  8. Study of the operational properties of the Capillary Plasma Electrode (CPE) discharges

    NASA Astrophysics Data System (ADS)

    Lopez, Jose; Jacome, David; Zhu, Wei-Dong; Figus, Margaret; Becker, Kurt H.

    2009-03-01

    Various approaches have been pursued to create stable atmospheric pressure discharges by extending the lifetime of the diffuse phase of the discharge to hundreds of microseconds. Previous research showed that the stability of the diffuse mode is dependent on the frequency (in the kHz range), gas type power, mode of the excitation, and geometrical confinement. Some of the most promising approaches are based on the recognition of the arc formation in high-pressure plasmas can be avoided and stable high-pressure plasma can be generated and maintained when the plasma are spatially constricted to the dimensions of tens to hundreds of microns. The Capillary Plasma Electrode (CPE) discharge is stable to produce stable atmospheric pressure nonequilibrium plasma. The CPE is similar in design to the Barrier Electrode Discharge, but has perforated dielectrics. The configuration, aside from exhibiting a diffuse mode of operation, also exhibits the so-called ``capillary jet'' mode, in which the capillaries “turn on” and a bright plasma jet emerges from the capillaries. The capillary jets from adjacent capillaries overlap so that the discharge appears uniform when the electrode contains an array of holes. There appears to be a threshold frequency for the capillary jet formation, which is strongly dependent on the L/D ratio of the capillaries, where D is diameter of the capillary and L its length. However, the operating principles and basic properties of this behavior are not well understood. The current work explores these modes of operations of the CPE by characterizing the electrical and optical emission properties of this discharge by examining a multi-hole discharge as well as a single capillary discharge reactor.

  9. Enhancement of the EUV emission of a metallic capillary discharge operated with argon ambient gas

    SciTech Connect

    Chan, L. S. Tan, D. Saboohi, S. Yap, S. L. Wong, C. S.

    2014-03-05

    In this work, the metallic capillary discharge is operated with two different ambients: air and argon. In the experiments reported here, the chamber is first evacuated to 10{sup −5} mbar. The discharge is initiated by the transient hollow cathode effect generated electron beam, with either air ambient or argon ambient at 10{sup −4} mbar. The bombardment of electron beam at the tip of the stainless steel anode gives rise to a metallic vapor, which is injected into the capillary and initiates the main discharge through the capillary. The EUV emission is measured for different discharge voltages for both conditions and compared. It is found that the metallic capillary discharge with argon ambientis able to produce higher EUV energy compared to that with air ambient.

  10. Laser ablation construction of on-column reagent addition devices for capillary electrophoresis.

    PubMed

    Rezenom, Yohannes H; Lancaster, Joseph M; Pittman, Jason L; Gilman, S Douglass

    2002-04-01

    A simple and reproducible technique for constructing perfectly aligned gaps in fused-silica capillaries has been developed for postcolumn reagent addition with capillary electrophoresis. This technique uses laser ablation with the second harmonic of a Nd:YAG laser (532 nm) at 13.5 mJ/pulse and a repetition rate of 15 Hz to create these gaps. A capillary is glued to a microscope slide and positioned at the focal point of a cylindrical lens using the focused beam from a laser pointer as a reference. Gaps of 14.0 +/- 2.2 microm (n = 33) at the bore of the capillary are produced with a success rate of 94% by ablation with 400 pulses. This simple method of gap construction requires no micromanipulation under a microscope, hydrofluoric acid etching, or use of column fittings. These structures have been used for reagent addition for postcolumn derivatization with laser-induced fluorescence detection and have been tested for the separation of proteins and amino acids. Detection limits of 6 x 10(-7) and 1 x 10(-8) M have been obtained for glycine and tranferrin, respectively. Separation efficiencies obtained using these gap reactors range from 38,000 to 213,000 theoretical plates.

  11. Extremely compact capillary discharge-based soft x-ray lasers and their application to dense plasma diagnostics

    NASA Astrophysics Data System (ADS)

    Rocca, Jorge

    2002-11-01

    Several applications, including the diagnostics of dense plasmas, require bright beams of coherent soft x-ray radiation. Recently significant progress has been made in the development of very compact high brightness soft x-ray lasers with excellent spatial coherence based on fast capillary discharges. Fast discharge-driven compressions in capillary channels produce axially uniform plasmas columns of narrow diameter in which saturated laser amplification is produced by collisional electron excitation of Ne-like ions. With laser pulse energies of several hundred μJ, peak spectral brightness of ˜ 2× 10^25 photons/ (s mm ^2 mrad ^2 0.01% bandwidth) and repetition rate of several Hz, the 46.9 nm the table-top Ne-like Ar capillary discharge laser has been successfully used in several applications. In long capillary plasma columns strong refractive anti-guiding and gain guiding act as an intrinsic mode selection mechanism that makes it possible to achieve essentially full spatial coherence. Such soft x-ray laser beams can probe scale-lengths and plasma densities beyond the limits that plasma refraction and absorption impose on optical laser probes, as initially demonstrated at Lawrence Livermore National Lab with a laboratory-size soft x-ray laser pumped by the Nova laser. With similar brightness, but much higher repetition rate and smaller foot print, the Ne-like Ar capillary discharge laser was used in the first table-top soft x-ray laser plasma diagnostics experiments, that include the shadowgraphy of micro-capillary discharges and interferometry of laser-created plasmas. In combination with a Mach-Zehnder interferometer that uses diffraction gratings as beam splitters it was used to study two-dimensional hydrodynamic effects in laser-created plasmas. Interferograms of plasmas generated at relatively low irradiation intensities (1×10^11- 7×10^12 W cm_2) with 13 ns FWHM duration light pulses revealed the unexpected formation of a concave density profile with a

  12. Analysis of Laser Pumping by Capillary Pinching Discharge in Argon and Nitrogen

    NASA Astrophysics Data System (ADS)

    Vrba, P.; Vrbová, M.; Jančárek, A.; Pína, L.; Tamáš, M.; Havlíková, R.; Palínek, S.; Tomassetti, G.; Ritucci, A.

    A comparative study of the capillary pinching discharges in argon and nitrogen is presented. Requirements on plasma parameters needed for laser collision and recombination pumping are stated. The results of the computer modelling are compared with previously published experimental results for argon laser and with recent experiments done with the same capillary filled by nitrogen.

  13. Exploring the Potential of Table-Top X-Ray Lasers and Capillary Discharge for Applications

    SciTech Connect

    Shlyaptev, V N; Dunn, J; Smith, R F; Moon, S J; Fournier, K B; Nilsen, J; Osterheld, A L; Kuba, J; Wootton, A J; Lee, R W; Rocca, J J; Rahman, A; Hammarsten, E; Filevich, J; Jankovska, E; Marconi, M C; Fornaciari, N; Buchenauer, D; Hender, H A; Kari,M S; Kanouff, M; Dimkoff, J; Kubiak, G; Shimkaveg, G; Silfvast, W T

    2003-05-08

    The advantages of using of table top x-ray lasers (XRLs) for different applications have been described. Examples of the first successful use of XRLs, the current efforts in applying them and the potential applications where an XRL can be used in future have been discussed. Modeling results showing the possibility of 3-4 times shorter wavelength capillary discharge x-ray lasers and calculated spectrum of Xe capillary EUV source are presented.

  14. Observation and numerical analysis of plasma parameters in a capillary discharge-produced plasma channel waveguide

    SciTech Connect

    Terauchi, Hiromitsu; Bobrova, Nadezhda; Sasorov, Pavel; Kikuchi, Takashi; Sasaki, Toru; Higashiguchi, Takeshi; Yugami, Noboru; Kodama, Ryosuke

    2011-03-01

    We observed the parameters of the discharge-produced plasma in cylindrical capillary. Plasma parameters of the waveguide were investigated by use of both a Normarski laser interferometer and a hydrogen plasma line spectrum. A space-averaged maximum temperature of 3.3 eV with electron densities of the order of 10{sup 17} cm{sup -3} was observed at a discharge time of 150 ns and a maximum discharge current of 200 A. One-dimensional dissipative magnetohydrodynamic (MHD) code was used to analyze the discharge dynamics in the gas-filled capillary discharge waveguide for high-intensity laser pulses. Simulations were performed for the conditions of the experiment. We compared the temporal behavior of the electron temperature and the radial electron density profiles, measured in the experiment with the results of the numerical simulations. They occurred to be in a good agreement. An ultrashort, intense laser pulse was guided by use of this plasma channel.

  15. GeV Electron Beams from a Capillary Discharge Guided Laser Plasma Accelerator

    SciTech Connect

    Nakamura, Kei; Gonsalves, Anthony; Panasenko, Dmitriy; Lin, Chen; Toth, Csaba; Geddes, Cameron; Schroeder, Carl; Esarey, Eric; Leemans, Wim

    2010-07-08

    Laser plasma acceleration (LPA) up to 1 GeV has been realized at Lawrence Berkeley National Laboratory by using a capillary discharge waveguide. In this paper, the capillary discharge guided LPA system including a broadband single-shot electron spectrometer is described. The spectrometer was designed specifically for LPA experiments and has amomentumacceptance of 0.01 - 1.1 GeV/c with a percent level resolution. Experiments using a 33 mm long, 300 mu m diameter capillary demonstrated the generation of high energy electron beams up to 1 GeV. By de-tuning discharge delay from optimum guiding performance, selftrapping and acceleration were found to be stabilized producing 460 MeV electron beams.

  16. Generation of high energy electron accelerated by using a tapered capillary discharge plasma

    NASA Astrophysics Data System (ADS)

    Kim, Minseok; Nam, Inhyuk; Lee, Taehee; Lee, Seungwoo; Suk, Hyyong

    2014-10-01

    The tapered plasma density in a gas-filled capillary waveguide can suppress the dephasing problem in laser wakefield acceleration (LWFA). As a result, the acceleration distance and the gained electron energy are expected to be increased. For this purpose, we developed a tapered capillary waveguide, which can produce a plasma density of ~ 1018 cm-3. Using this capillary discharge plasma, we performed the acceleration experiments with the high power laser system (20 TW/40 fs) constructed at GIST. In this presentation, the detailed electron acceleration experiments will be reported.

  17. Measurements of Rotational Temperatures in Atmospheric-Pressure Capillary Plasma Electrode (CPE) Discharge

    NASA Astrophysics Data System (ADS)

    Figus, Margaret; Abramzon, Nina; Becker, Kurt

    2003-10-01

    We report the results of rotational temperature measurements in atmospheric-pressure capillary plasma electrode (CPE) discharges in ambient air using the unresolved N2 second positive band. Assuming that the emitting N2 molecules can be described by a Maxwell-Boltzmann distribution characterized by a single rotational temperature, this temperature is determined from a fit of the measured emission spectrum to a calculated spectrum. If the emitting species are in equilibrium with the bulk gas in the plasma, then this temperature can be interpreted as the gas kinetic temperature in the plasma. We determined rotational temperatures for three different plasma regions: inside the capillary by analyzing radiation emitted along the axis of the capillary, between the capillaries, and perpendicular to the axis of the capillary. Each region has a different plasma density and, therefore, a different gas temperature with the plasma inside the capillary being the hottest. We also measured the rotational temperatures in each region as a function of the plasma power. As expected, the rotational temperatures increase with increasing discharge power. Work supported by the NSF and by ARO through a DURIP award.

  18. Modeling the capillary discharge of an electrothermal (ET) launcher

    NASA Astrophysics Data System (ADS)

    Least, Travis

    Over the past few decades, different branches of the US Department of Defense (DoD) have invested at improving the field ability of electromagnetic launchers. One such focus has been on achieving hypervelocity launch velocities in excess of 7 km/s for direct launch to space applications [1]. It has been shown that pre-injection is required for this to be achieved. One method of pre-injection which has promise involves using an electro-thermal (ET) due to its ability to achieve the desired velocities with a minimal amount of hot plasma injected into the launcher behind the projectile. Despite the demonstration of pre-injection using this method, polymer ablation is not very well known and this makes it challenging to predict how the system will behave for a given input of electrical power. In this work, the rate of ablation has been studied and predicted using different models to generate the best possible characteristic curve. [1] - Wetz, David A., Francis Stefani, Jerald V. Parker, and Ian R. McNab. "Advancements in the Development of a Plasma-Driven Electromagnetic Launcher." IEEE TRANSACTIONS ON MAGNETICS 45.1 (2009): 495--500. IEEE Xplore. Web. 18 Aug. 2012.

  19. A high voltage pulsed power supply for capillary discharge waveguide applications

    SciTech Connect

    Abuazoum, S.; Wiggins, S. M.; Issac, R. C.; Welsh, G. H.; Vieux, G.; Jaroszynski, D. A.; Ganciu, M.

    2011-06-15

    We present an all solid-state, high voltage pulsed power supply for inducing stable plasma formation (density {approx}10{sup 18} cm{sup -3}) in gas-filled capillary discharge waveguides. The pulser (pulse duration of 1 {mu}s) is based on transistor switching and wound transmission line transformer technology. For a capillary of length 40 mm and diameter 265 {mu}m and gas backing pressure of 100 mbar, a fast voltage pulse risetime of 95 ns initiates breakdown at 13 kV along the capillary. A peak current of {approx}280 A indicates near complete ionization, and the r.m.s. temporal jitter in the current pulse is only 4 ns. Temporally stable plasma formation is crucial for deploying capillary waveguides as plasma channels in laser-plasma interaction experiments, such as the laser wakefield accelerator.

  20. Temporal evolution of electron density and temperature in capillary discharge plasmas

    NASA Astrophysics Data System (ADS)

    Oh, Seong Y.; Uhm, Han S.; Kang, Hoonsoo; Lee, In W.; Suk, Hyyong

    2010-05-01

    Time-resolved spectroscopic measurements of a capillary discharge plasma of helium gas were carried out to obtain detailed information about dynamics of the discharge plasma column, where the fast plasma dynamics is determined by the electron density and temperature. Our measurements show that the electron density of the capillary plasma column increases sharply after gas breakdown and reaches its peak of the order of 1018 cm-3 within less than 100 ns, and then it decreases as time goes by. The result indicates that a peak electron density of 2.3×1018 cm-3 occurs about 65 ns after formation of the discharge current, which is ideal for laser wakefield acceleration experiments reported by Karsch et al. [New J. Phys. 9, 415 (2007)].

  1. High efficiency guiding of terawatt subpicosecond laser pulses in a capillary discharge plasma channel

    NASA Astrophysics Data System (ADS)

    Kaganovich, D.; Ting, A.; Moore, C. I.; Zigler, A.; Burris, H. R.; Ehrlich, Y.; Hubbard, R.; Sprangle, P.

    1999-05-01

    Transmission efficiencies in excess of 75% were obtained in the optical guiding of subpicosecond, terawatt laser pulses in a 2-cm-long capillary discharge plasma channel at the Naval Research Laboratory. The guided laser beam size at the exit of the channel was measured using far field imaging and Thomson scattering techniques. The guided laser intensity was >1×1017 W/cm2 at a guided beam diameter of 35 μm for a propagation length of 22 Rayleigh ranges. There is evidence that the plasma channel extends beyond the ends of the capillary and affects the far field beam structure of the transmitted laser pulse.

  2. Generation of dc pin-hole discharges in liquids: comparison of discharge breakdown in diaphragm and capillary configuration

    NASA Astrophysics Data System (ADS)

    Kozáková, Zdenka; Krčma, František; Vašíček, Michal; Hlavatá, Lucie; Hlochová, Lenka

    2015-04-01

    Electrical discharges in liquids can be generated in several electrode configurations; one of them is called as a pin-hole. The discharge is created inside a small orifice in the dielectric barrier connecting two chambers filled by any conductive solution. Each chamber contains one electrode. Based on the orifice length/diameter ratio, the discharge is called as a capillary or diaphragm discharge. The present paper gives the first detailed observation of the dependence of discharge creation on the orifice shape for selected NaCl solution conductivities (250-1000 μS cm-1). As a dielectric barrier, ceramic discs with thickness varying from 0.3 to 1.5 mm were used. Diameter of one central pin-hole was in the range of 0.25-1.00 mm. The non-pulsing dc high voltage up to 2 kV with power up to 500 W was used for the presented study. The bubble theory of the discharge generation was confirmed at the set conditions.

  3. Capillary Dielectric Barrier Discharge: Transition from Soft Ionization to Dissociative Plasma.

    PubMed

    Klute, Felix David; Michels, Antje; Schütz, Alexander; Vadla, Cedomil; Horvatic, Vlasta; Franzke, Joachim

    2016-05-03

    A capillary He dielectric barrier discharge was investigated with respect to its performance as a soft or dissociative ionization source. Spatiotemporal measurements of the plasma emission showed that in one voltage duty cycle the plasma evolved from a soft to dissociative ionization source. At the earliest time, the soft plasma was generated between the electrodes as well as outside the capillary forming the plasma jet. It was characterized by significant radiation arising only from He and N2(+), which are known to be important in the process of the soft ionization of the analyte. Later in time, the plasma capable of dissociating molecules develops. It is characterized by appreciable radiation from analyte dissociation products and is restricted to the interelectrode region in the capillary. Thus, for the soft ionization purposes, it is feasible to introduce the analyte exclusively in the plasma jet. For elemental analysis, the interelectrode plasma is appropriate.

  4. Wall ablation of heated compound-materials into non-equilibrium discharge plasmas

    NASA Astrophysics Data System (ADS)

    Wang, Weizong; Kong, Linghan; Geng, Jinyue; Wei, Fuzhi; Xia, Guangqing

    2017-02-01

    The discharge properties of the plasma bulk flow near the surface of heated compound-materials strongly affects the kinetic layer parameters modeled and manifested in the Knudsen layer. This paper extends the widely used two-layer kinetic ablation model to the ablation controlled non-equilibrium discharge due to the fact that the local thermodynamic equilibrium (LTE) approximation is often violated as a result of the interaction between the plasma and solid walls. Modifications to the governing set of equations, to account for this effect, are derived and presented by assuming that the temperature of the electrons deviates from that of the heavy particles. The ablation characteristics of one typical material, polytetrafluoroethylene (PTFE) are calculated with this improved model. The internal degrees of freedom as well as the average particle mass and specific heat ratio of the polyatomic vapor, which strongly depends on the temperature, pressure and plasma non-equilibrium degree and plays a crucial role in the accurate determination of the ablation behavior by this model, are also taken into account. Our assessment showed the significance of including such modifications related to the non-equilibrium effect in the study of vaporization of heated compound materials in ablation controlled arcs. Additionally, a two-temperature magneto-hydrodynamic (MHD) model accounting for the thermal non-equilibrium occurring near the wall surface is developed and applied into an ablation-dominated discharge for an electro-thermal chemical launch device. Special attention is paid to the interaction between the non-equilibrium plasma and the solid propellant surface. Both the mass exchange process caused by the wall ablation and plasma species deposition as well as the associated momentum and energy exchange processes are taken into account. A detailed comparison of the results of the non-equilibrium model with those of an equilibrium model is presented. The non-equilibrium results

  5. A capillary discharge as a potential x-ray laser driver.

    PubMed

    Peterson, B G; Ivanova, E P; Spencer, R L; Hart, G W; Lin, J; Stark, T T; Panin, A M; Knight, L V

    1995-01-01

    This paper describes a combined theoretical and experimental approach to understanding the capillary spark discharge with specific application to use as a soft x-ray or extreme ultraviolet laser source. Atomic physics calculations have identified several potential laser lines in a collisionally pumped neon-like or nickel-like plasma, and magnetohydrodynamic (MHD) modeling has shown that a capillary discharge device should be capable of producing the correct plasma conditions to achieve a population inversion in some of these lines. An experiment is constructed to evaluate the accuracy of the MHD model and investigate the potential of observing inversion in a neon-like argon or a nickel-like krypton plasma.

  6. The Effect of Ignition Techniques on a Capillary Discharge Based Pulsed Plasma Thruster

    DTIC Science & Technology

    2009-06-25

    discharge plasma sources utilizing the surface flashover ignition method showed propulsion efficiencies of 8-18% within an Isp range between 350 and 650 s...operation. Capillary dis- charge plasma sources utilizing the surface flashover ignition method showed propulsion efficiencies of 8-18% within an Isp...at ignition caused by an exploding wire, the Paschen breakdown of gas, and a surface flashover caused by the addition of a third electrode

  7. A compact, low cost Marx bank for generating capillary discharge plasmas

    NASA Astrophysics Data System (ADS)

    Dyson, A. E.; Thornton, C.; Hooker, S. M.

    2016-09-01

    We describe in detail a low power Compact Marx Bank (CMB) circuit that can provide 20 kV, 500 A pulses of approximately 100-200 ns duration. One application is the generation of capillary discharge plasmas of density ≈1018 cm-3 used in laser plasma accelerators. The CMB is triggered with a high speed solid state switch and gives a high voltage output pulse with a ns scale rise time into a 50 Ω load (coaxial cable) with <4 ns voltage jitter. Its small size (10 cm × 25 cm × 5 cm) means that it can be placed right next to the capillary discharge in the target chamber to avoid the need to impedance match. The electrical energy required per discharge is <1 J, and the CMB can be run at shot repetition rates of ≳1 Hz. This low power requirement means that the circuit can easily be powered by a small lead acid battery and, therefore, can be floated relative to laboratory earth. The CMB is readily scalable and pulses >45 kV are demonstrated in air discharges.

  8. Plasma Parameter of a Capillary Discharge-Produced Plasma Channel to Guide an Ultrashort Laser Pulse

    SciTech Connect

    Higashiguchi, Takeshi; Terauchi, Hiromitsu; Bai, Jin-xiang; Yugami, Noboru

    2009-01-22

    We have observed the optical guiding of a 100-fs laser pulse with the laser intensity in the range of 10{sup 16} W/cm{sup 2} using a 1.5-cm long capillary discharge-produced plasma channel for compact electron acceleration applications. The optical pulse propagation using the plasma channel is achieved with the electron densities of 10{sup 17}-10{sup 18} cm{sup -3} and the electron temperatures of 0.5-4 eV at a discharge time delay of around 150 ns and a discharge current of 500 A with a pulse duration of 100-150 ns. An energy spectrum of the accelerated electrons from a laser-plasma acceleration scheme showed a peak at 1.3 MeV with a maximum energy tail of 1.6 MeV.

  9. Dynamics and density distributions in a capillary-discharge waveguide with an embedded supersonic jet

    SciTech Connect

    Matlis, N. H. Gonsalves, A. J.; Steinke, S.; Tilborg, J. van; Shaw, B.; Mittelberger, D. E.; Geddes, C. G. R.; Matlis, E. H.; Leemans, W. P.

    2015-11-28

    We present an analysis of the gas dynamics and density distributions within a capillary-discharge waveguide with an embedded supersonic jet. This device provides a target for a laser plasma accelerator which uses longitudinal structuring of the gas-density profile to enable control of electron trapping and acceleration. The functionality of the device depends sensitively on the details of the density profile, which are determined by the interaction between the pulsed gas in the jet and the continuously-flowing gas in the capillary. These dynamics are captured by spatially resolving recombination light from several emission lines of the plasma as a function of the delay between the jet and the discharge. We provide a phenomenological description of the gas dynamics as well as a quantitative evaluation of the density evolution. In particular, we show that the pressure difference between the jet and the capillary defines three regimes of operation with qualitatively different longitudinal density profiles and show that jet timing provides a sensitive method for tuning between these regimes.

  10. Water-assisted CO(2) laser ablated glass and modified thermal bonding for capillary-driven bio-fluidic application.

    PubMed

    Chung, C K; Chang, H C; Shih, T R; Lin, S L; Hsiao, E J; Chen, Y S; Chang, E C; Chen, C C; Lin, C C

    2010-02-01

    The glass-based microfluidic chip has widely been applied to the lab-on-a-chip for clotting tests. Here, we have demonstrated a capillary driven flow chip using the water-assisted CO(2) laser ablation for crackless fluidic channels and holes as well as the modified low-temperature glass bonding with assistance of adhesive polymer film at 300 degrees Celsius. Effect of water depth on the laser ablation of glass quality was investigated. The surface hydrophilic property of glass and polymer film was measured by static contact angle method for hydrophilicity examination in comparison with the conventional polydimethylsiloxane (PDMS) material. Both low-viscosity deionized water and high-viscosity whole blood were used for testing the capillary-driving flow behavior. The preliminary coagulation testing in the Y-channel chip was also performed using whole blood and CaCl(2) solution. The water-assisted CO(2) laser processing can cool down glass during ablation for less temperature gradient to eliminate the crack. The modified glass bonding can simplify the conventional complex fabrication procedure of glass chips, such as high-temperature bonding, long consuming time and high cost. Moreover, the developed fluidic glass chip has the merit of hydrophilic behavior conquering the problem of traditional hydrophobic recovery of polymer fluidic chips and shows the ability to drive high-viscosity bio-fluids.

  11. Development and fundamental investigation of Laser Ablation Glow Discharge Time-Of-Flight Mass Spectrometry (LA-GD-TOFMS)

    NASA Astrophysics Data System (ADS)

    Tarik, Mohamed; Lotito, Giovanni; Whitby, James A.; Koch, Joachim; Fuhrer, Katrin; Gonin, Marc; Michler, Johann; Bolli, Jean-Luc; Günther, Detlef

    2009-03-01

    Glow Discharge (GD) spectroscopy is a well known and accepted technique for the bulk and surface composition analysis, while laser ablation (LA) provides analysis with high spatial-resolution analysis in LIBS (laser-induced breakdown spectroscopy) or when coupled to inductively coupled plasma spectrometry (ICP-OES or ICP-MS). This work concerns the construction of a Laser Ablation Glow Discharge Time-Of-Flight Mass Spectrometry (LA-GD-TOFMS) instrument to study the analytical capabilities resulting from the interaction of a laser-generated sample plume with a pulsed glow discharge. Two ablation configurations were studied in detail. In a first approach, the laser-generated plume was introduced directly into the GD, while the second approach generated the plume inside the GD. The ablated material was introduced at different times with respect to the discharge pulse in order to exploit the efficient ionization in the GD plasma. For both LA-GD configurations, direct ablation into the afterglow of the pulsed glow discharge leads to an ion signal enhancement of up to a factor of 7, as compared to the ablation process alone under the same experimental conditions. The LA-GD enhancement was found to occur exclusively in the GD afterglow, with a maximum ablation S/N occurring in a few hundred microseconds after the termination of the glow discharge. The duration of the enhanced signal is about two milliseconds. Both the laser pulse energy and the position of the ablation plume (with respect to the sampling orifice) were found to affect the amount of mass entering the afterglow region and consequently, the enhancement factor of ionization.

  12. DC Underwater Capillary Discharge With Symmetrical Hole: Diagnostics and Pumping Effect

    NASA Astrophysics Data System (ADS)

    Halamová, Ivana; Nikiforov, Anton; Krčma, František; Leys, Christophe

    2014-06-01

    Capillary discharge investigated by this work was created in the reactor using positive half-cycle of AC high voltage up to 2 kV. Electric field created between two electrodes which were separated by the dielectric ceramic barrier with a symmetrical cylindrical hole (diameter of 1 mm, length of 5 mm) in it. When voltage reached the value sufficient for liquid breakdown, the discharge appeared initially in bubbles of evaporated solution in the hole vicinity and spread further into the liquid volume. After the rise of discharge, two kinds of plasma channels (streamers) propagated towards electrodes from the pin-hole: longer positive streamers on the side with the cathode (analogically as in the positive corona discharge) and shorter negative streamers (like negative corona discharge). These streamer kinds differed especially in the energy dissipation originating from different electron velocities in plasma channels due to electron collisions with positive particles accelerating or decelerating electron avalanches and it gave rise of a significant pump effect.

  13. Benchmarked Simulations of Slow Capillary Discharges for Laser-Plasma Accelerators

    NASA Astrophysics Data System (ADS)

    Johnson, Jeffrey; Colella, Phillip; Geddes, Cameron; Mittelberger, Daniel; Bulanov, Stepan; Esarey, Eric; Leemans, Wim; Applied Numerical Algorithms Group (Lbl) Team; Loasis Laboratory (Lbl) Team

    2011-10-01

    We report our progress on a non-equilibrium, 2-temperature plasma model used for slow capillary discharges pertinent to laser-plasma accelerators. In these experiments, energy transport plays a major role in the formation of a plasma channel, which is used to guide the laser and enhance acceleration. We describe a series of simulations used to study the effects of electrical and thermal conduction, diffusion, and externally-applied magnetic fields in present and ongoing experiments with relevant geometries and densities. Scylla, a 1D cylindrical plasma/hydro code, was used to explore transport models and to resolve the radial profile of the plasma within the capillary. It has also been benchmarked against existing codes and experimental data. Since the capillary has 3D features such as gas feed slots, we have begun implementing a multi-dimensional AMR plasma model that solves the governing equations on irregular domains. Application to the BELLA Project at LBNL will be discussed. This work was supported by the Department of En- ergy under contract number DE-AC02-05-CH11231.

  14. Investigation on the characteristics of a two gap capillary discharge based on surface flash over ignition in atmosphere

    NASA Astrophysics Data System (ADS)

    Huang, Dong; Yang, Lanjun; Huo, Peng; Ma, Jiangbo; Guo, Haishan; Xu, Ran; Ding, Weidong

    2016-09-01

    In this paper, a two gap capillary (TGC) structure is presented and the corresponding driving circuit based on surface flashover ignition is designed to achieve reliable and repetitive discharge in atmosphere. The characteristics of the two gap capillary (TGC) discharge in low energy are investigated, of which the discharge energy is from 27 J to 432 J. With the rise of charging voltage, the delay of the weak capillary discharge and the main discharge both decrease. Meanwhile, the current flowing through the main gap and the plasma jet ejection are enhanced. The main gap resistance is about several hundreds of milliohms in the main discharge and rises gradually with the decay of the current. The long tail extinction is witnessed at the relatively low charging voltage of 0.5 kV and 1.0 kV, by which the pulse width of the discharge is extended. However, the discharge during the long tail extinction contributes little to the plasma jet ejection with negligible plasma jet velocity and low degree of the plasma ionization. The effective energy deposition efficiency on the main gap increases gradually with the charging voltage and reaches approximately 2 times higher than that of the traditional structure at the charging voltage of 2.0 kV. The series inductor in the circuit can restrain the development of the long tail extinction and increase the effective energy deposition efficiency. Thus, the discharge characteristics and the plasma ejection of TGC under the relatively low charging voltage are optimized.

  15. Diurnal discharge fluctuations and streambed ablation in a supraglacial stream on the Vaughan-Lewis and Gilkey glaciers, Juneau Icefield, Alaska

    SciTech Connect

    Stock, J.W. |; Pinchak, A.C. |

    1995-12-31

    The study reported here focuses on the dynamics of two supraglacial streams on the Juneau Icefield in southeast Alaska. Data on streambed ablation (melting) rates, stream discharge, radiation, and air temperature and humidity were collected in August 1990 and 1991. Radiation had the greatest effect on stream discharge. Daily peak discharges occurred only 30 minutes after peak radiation, but two hours after peak temperature. Factors influencing variation in discharge of the streams were velocity, stream depth, and stream width, in decreasing order of importance. Streambed ablation due to radiation was greater than glacier surface ablation due to radiation. Streambed ablation due to frictional heating was very small.

  16. Plasma Dynamics and VUV Emission in a Fast Hollow Cathode Capillary Discharge

    NASA Astrophysics Data System (ADS)

    Soto, Leopoldo; Esaulov, Andrey; Silva, Patricio; Sylvester, Gustavo; Moreno, José; Zambra, Marcelo; Nazarenko, Andrey

    2000-10-01

    Following the world tendency to study the physical mechanisms to obtain laser emission in the VUV to soft X-ray region in table-top device, a fast capillary discharge has been constructed at Comisión Chilena de Energía Nuclear, CCHEN. The device is identical to designed by P. Choi and M. Favre, included an electron beam from the hollow cathode region to provide ionization on the axis (1). The discharge operates in Argon with a cathode pressure of 100-500 mtorr. The system works with differential vacuum, thus the anode pressure is around five times less than the cathode pressure. The radius of capillary is 0.4 mm and the length is 2.5 cm. For an applied voltage of 10 kV a peak current of 5 kA with a rise time of 4.8 ns is obtained (10^12 A/s). MHD simulations in order to study the plasma dynamics an temperature evolution were performed (2). A final radius of 100-200 microns is expected at 8 ns, 2 ns after the peak current with a electron density of 2 x 10^18 cm-3. An electron and ion temperature of 80 and 40 eV respectively are predicted. In addition to usual electrical diagnostics, time-space resolution pinhole images (multipinhole camera with a multichannel plate, four frames, one frame every 4 ns) and time resolved spectra in the region of 10 to 100 nm were performed. Dynamics of plasma compresion was studied from time resolved pinhole images. Detected spectra show that plasma consists of argon ions with ionization potential from ArVI to ArX. This work has been funded by FONDECYT grant 1980187 and a Presidential Chair in Science granted by Chilean government. Authors are thankful to K. Koshelev and P. Antsiferov (ISAN, Troitsk) for fruitful discussions and comments. 1.- P. Choi and M. Favre, Rev. Sci. Instrum. 69, 3118, (1998) 2.- A. Esaulov, P. Sasorov, L. Soto, M. Zambra and J. Sakai, ``Fast Hollow Cathode Capillary Discharge. MHD Simulation''. Submitted for publication.

  17. Soft X-Ray Emission Analysis Of A Pulsed Capillary Discharge Operated In Nitrogen

    NASA Astrophysics Data System (ADS)

    Valdivia, M. P.; Valenzuela, J. C.; Wyndham, E. S.; Favre, M.; Chuaqui, H.; Bhuyan, H.

    2014-05-01

    We present results from a pulsed capillary ns discharge source, operated in Nitrogen and N/He mixtures, in an alumina capillary 2.1mm long with outer diameter of 6.3mm and inner diameter of 1.6mm. The electrical energy stored is 0.5J with peak current of 6kA. Fast charging from an IGBT based pulsed power circuit allows operation at 35-600 Hz with voltages in the range of 18-24kV. Characteristic time-integrated N/He spectra were recorded and analyzed for values of 20-200 Å, with clear evidence of He-like Nitrogen emission at 28.8Å, which represents a possible source for water window soft x-ray microscopy. Filtered diode measurements reveal the influence of axial electron beams, generated by hollow cathode dynamics, on the x-ray emission in the range of 300-450 eV. We discuss optimal voltage applied and pressure conditions for soft x-ray generation. Time-integrated MCP images of a filtered slit-wire system delivered clear evidence of full wall detachment with ~500μm in radial size for the entire emission range and ~200μm for the emission in the 300-450 eV range.

  18. Pulsed laser ablation of borax target in vacuum and hydrogen DC glow discharges

    NASA Astrophysics Data System (ADS)

    Kale, A. N.; Miotello, A.; Mosaner, P.

    2006-09-01

    The aim of our experiment was to produce a material with B sbnd H bonds for applications in hydrogen storage and generation. By using KrF excimer laser ( λ = 248 nm) ablation of borax (Na 2B 4O 7) target, thin films were deposited on KBr and silicon substrates. Ablation was performed both in vacuum and in hydrogen atmosphere. DC glow discharge technique was utilized to enhance hydrogen gas ionization. Experiments were performed using laser fluence from 5 to 20 J/cm 2. Films were deposited under gas pressure of 1 × 10 -5 to 5 × 10 -2 mbar and substrate temperatures of 130-450 °C. Scanning electron microscopy analysis of films showed presence of circular particulates. Film thickness, roughness and particulates number increased with increase in laser fluence. Energy dispersive X-ray spectroscopy analysis shows that sodium content in the particulates is higher than in the target. This effect is discussed in terms of atomic arrangements (both at surface and bulk) in systems where ionic and covalent bonds are present and by looking at the increased surface/bulk ratio of the particulates with respect to the deposited films. The Fourier transform infrared spectroscopy measurements showed presence of B sbnd O stretching and B sbnd O sbnd B bending bonds. Possible reasons for absence of B sbnd H bonds are attributed to binding enthalpy of the competing molecules.

  19. Plasma formation using a capillary discharge in water and its application to the sterilization of E. coli

    NASA Astrophysics Data System (ADS)

    Hong, Yong Cheol; Park, Hyun Jae; Lee, Bong Ju; Kang, Won-Seok; Uhm, Han Sup

    2010-05-01

    An underwater electrical discharge in a narrow dielectric capillary provides the details of the evolution of microbubbles to plasma as formed by a tungsten electrode inserted in the capillary. An increase in the applied voltage forms microbubbles after water fills the capillary. A further increase in the voltage generates a surface discharge through the boundary of the bubble, elongating the bubble shape, and eventually forming plasma by electrical breakdown. This produces atomic oxygen, atomic hydrogen, and hydroxyl radicals from dissociation of water vapor. Also, a bactericidal test in normal saline solution showed that more than 99.6% of the bacterial cells were killed within 8 s, resulting from chlorine-containing species, in particular hypochlorous acid as a major bactericidal agent.

  20. Can We Optimize Arc Discharge and Laser Ablation for Well-Controlled Carbon Nanotube Synthesis?

    NASA Astrophysics Data System (ADS)

    Das, Rasel; Shahnavaz, Zohreh; Ali, Md. Eaqub; Islam, Mohammed Moinul; Abd Hamid, Sharifah Bee

    2016-11-01

    Although many methods have been documented for carbon nanotube (CNT) synthesis, still, we notice many arguments, criticisms, and appeals for its optimization and process control. Industrial grade CNT production is urgent such that invention of novel methods and engineering principles for large-scale synthesis are needed. Here, we comprehensively review arc discharge (AD) and laser ablation (LA) methods with highlighted features for CNT production. We also display the growth mechanisms of CNT with reasonable grassroots knowledge to make the synthesis more efficient. We postulate the latest developments in engineering carbon feedstock, catalysts, and temperature cum other minor reaction parameters to optimize the CNT yield with desired diameter and chirality. The rate limiting steps of AD and LA are highlighted because of their direct role in tuning the growth process. Future roadmap towards the exploration of CNT synthesis methods is also outlined.

  1. Lasing in Ne-Like Argon Capillary Discharge at Low Current and the Effect of Current Prepulse

    SciTech Connect

    Kwek, K. H.; Tan, C. A.

    2009-01-21

    The output characteristics of saturated capillary discharge 46.9 nm Ne-like argon soft x-ray laser obtained with relatively low main discharge current of less than 20 kA, with the lowest being 9 kA. The 3 mm diameter and 200 mm long alumina capillary with Argon filling pressure range between 0.1-0.4 mbar was pumped by a discharge current with a quarter-cycle of about 40 ns. A current pulse with a typical RC shape (decay time {approx}30 {mu}s) was used as a prepulse. Measurements indicate that the laser output is affected by the timing of the application of the prepulse. This effect is most significant when the time delay between the application of the prepulse and the onset of the main current is around 2 to 4 {mu}s, and beyond these times, the effect is less significant.

  2. A comparative study of silver nanoparticles synthesized by arc discharge and femtosecond laser ablation in aqueous solution

    NASA Astrophysics Data System (ADS)

    Zhang, Hongqiang; Zou, Guisheng; Liu, Lei; Li, Yong; Tong, Hao; Sun, Zhenguo; Zhou, Y. Norman

    2016-10-01

    Silver nanoparticles have been synthesized by arc discharge and femtosecond laser ablation in polyvinylpyrrolidone (PVP) aqueous solution. Both methods are the simple, cost-effective and environment-friendly way to obtain the purity silver nanoparticles. In this study, the structure, composition, morphology, size and distribution, stability, production rate and sintering properties of silver nanoparticles synthesized by both methods were compared. The spherical or pseudo-spherical silver nanoparticles were synthesized by both methods, and the diameters were below 50 nm. The arc discharge-synthesized particle distribution varied with the breakdown voltage, and laser-synthesized particle size mainly depended on the laser energy. PVP solution could cap and stabilize the silver nanoparticles by Ag-O bond, while arc discharge and laser ablation resulted in some level of PVP degradation during processing. Sliver nanoparticle colloids synthesized by both methods had the high negative values of zeta potential and exhibited the good stability. The maximum production rates of the silver nanoparticles synthesized by arc discharge and femtosecond laser ablation were 6.0 and 3.0 mg/min, respectively. In addition, the sintering properties of silver nanoparticles synthesized by both methods were also discussed.

  3. An interface for online coupling capillary electrophoresis to dielectric barrier discharge ionization mass spectrometry.

    PubMed

    Zhang, Yiding; Ai, Wanpeng; Bai, Yu; Zhou, Yinglin; Wen, Luhong; Zhang, Xinxiang; Liu, Huwei

    2016-12-01

    The online combination of capillary electrophoresis (CE) with mass spectrometry (MS) has long been desired for the capability of direct and simultaneous separation and detection with high efficiency, accuracy, and throughput. In this work, a novel CE-MS interface was developed, using dielectric barrier discharge ionization (DBDI). The interface employed a spray tip with a coaxial three-layer structure, into which the CE sample solution, the sheath liquid, and the nebulizing gas were introduced. The spray tip was put between the DBDI outlet and the MS inlet, thus the CE sample solution could be blended with the sheath liquid, then nebulized. The nebulized sample could be ionized by DBDI, and finally analyzed by MS. The key parameters of the interface were optimized. Then, proof-of-concept experiments separating and detecting the mixture of metronidazole and acetaminophen solutions were conducted. The results showed high separation efficiency, low time consumption, high reproducibility, and convenience in operation. In addition, the interface exhibited a high tolerance of non-volatile salts and surfactants, which would be widely used in CE analyses. All of these results demonstrated that the newly developed CE-DBDI-MS interface could be successfully used in CE-MS studies, and could be further utilized in multiple areas involving efficient separation and detection.

  4. Table-top water-window soft X-ray microscope using a Z-pinching capillary discharge source

    NASA Astrophysics Data System (ADS)

    Nawaz, M. F.; Nevrkla, M.; Jancarek, A.; Torrisi, A.; Parkman, T.; Turnova, J.; Stolcova, L.; Vrbova, M.; Limpouch, J.; Pina, L.; Wachulak, P.

    2016-07-01

    The development and demonstration of a table-top transmission soft X-ray (SXR) microscope, using a laboratory incoherent capillary discharge source has been carried out. This Z-pinching capillary discharge water-window SXR source, is a first of its kind to be used for high spatial resolution microscopy at λ = 2.88 nm (430 eV) . A grazing incidence ellipsoidal condenser mirror is used for focusing of the SXR radiation at the sample plane. The Fresnel zone plate objective lens is used for imaging of the sample onto a back-illuminated (BI) CCD camera. The achieved half-pitch spatial resolution of the microscope approaches 100 nm, as demonstrated by the knife-edge test. Details about the source, and the construction of the microscope are presented and discussed. Additionally, the SXR images of various samples, proving applicability of such microscope for observation of objects in the nanoscale, are shown.

  5. Formation of sub-micron size carbon structures by plasma jets emitted from a pulsed capillary discharge

    NASA Astrophysics Data System (ADS)

    Bhuyan, H.; Favre, M.; Valderrama, E.; Avaria, G.; Wyndham, E.; Chuaqui, H.; Baier, J.; Kelly, H.; Grondona, D.; Marquez, A.

    2009-01-01

    We have performed an experimental investigation of the potential use of intense plasma jets produced in a repetitive pulsed capillary discharge (PCD) operating in methane gas, to irradiate Si (1 0 0) substrates. The surface modifications induced by the plasma jet using two different material inserts at the capillary end, graphite and titanium, are characterized using standard surface science diagnostic tools, such as scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) analysis and Raman spectroscopy (RS). It has been found that the application of methane plasma jet results in the formation of sub-micron size carbon structures. It is observed that the resulting plasma irradiated surface morphologies are different, depending on the different material inserts used at the capillary end, at otherwise identical operational conditions. To investigate the species responsible for the observed surface changes in different material inserts to the capillary, optical-emission spectroscopy (OES) was recorded using a 300-1000 nm spectrometer. The OES results show the presence of H, CH and C 2 Swan band in the discharge plasma, which play a significant role in the formation of the carbon structures.

  6. A Zero Dimensional Time-Dependent Model of High-Pressure Ablative Capillary Discharge (Preprint)

    DTIC Science & Technology

    2008-06-01

    index i: a e ae AM mkT 12 0 ⋅⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ ⋅ ⋅⋅≈Δ <=>ε , ∑ ⋅ ∑ ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ ⋅ = ∑ ∑ ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ = k aea k a aea k ea k a ea a kk k kk k

  7. Investigation of capillary nanosecond discharges in air at moderate pressure: comparison of experiments and 2D numerical modelling

    NASA Astrophysics Data System (ADS)

    Klochko, Andrei V.; Starikovskaia, Svetlana M.; Xiong, Zhongmin; Kushner, Mark J.

    2014-09-01

    Nanosecond electrical discharges in the form of ionization waves are of interest for rapidly ionizing and exciting complex gas mixtures to initiate chemical reactions. Operating with a small discharge tube diameter can significantly increase the specific energy deposition and so enable optimization of the initiation process. Analysis of the uniformity of energy release in small diameter capillary tubes will aid in this optimization. In this paper, results for the experimentally derived characteristics of nanosecond capillary discharges in air at moderate pressure are presented and compared with results from a two-dimensional model. The quartz capillary tube, having inner and outer diameters of 1.5 and 3.4 mm, is about 80 mm long and filled with synthetic dry air at 27 mbar. The capillary tube with two electrodes at the ends is inserted into a break of the central wire of a long coaxial cable. A metal screen around the tube is connected to the cable ground shield. The discharge is driven by a 19 kV 35 ns voltage pulse applied to the powered electrode. The experimental measurements are conducted primarily by using a calibrated capacitive probe and back current shunts. The numerical modelling focuses on the fast ionization wave (FIW) and the plasma properties in the immediate afterglow after the conductive plasma channel has been established between the two electrodes. The FIW produces a highly focused region of electric field on the tube axis that sustains the ionization wave that eventually bridges the electrode gap. Results from the model predict FIW propagation speed and current rise time that agree with the experiment.

  8. A Study of Ignition Effects on Thruster Performance of a Multi-Electrode Capillary Discharge Using Visible Emission Spectroscopy Diagnostics

    DTIC Science & Technology

    2009-09-01

    leads to an impedance collapse. 21 The mechanisms involved in fully understanding surface flashover are complicated. For ignition of the main capillary...particles that create a conductive path for the discharge to occur. It is speculated that the mechanisms that start the surface flashover in the ignitor...polyethylene insulator. Here the flashover occurs axially instead of radially. There are two main schools of thought behind surface flashover . One

  9. Capillary - Discharge Based Hand-Held Detector For Chemical Vapor Monitoring

    DOEpatents

    Duan, Yixiang

    2005-05-31

    A handheld/portable detector for chemical vapor monitoring includes a housing and a discharge chamber that is established therein. The plasma discharge has a relatively small volume, e.g., in the micro-liter range. A first electrode and a second electrode are disposed within the discharge chamber and a discharge gap is established therebetween. A sample gas tube is in fluid communication with the discharge chamber and provides a sample gas to the discharge chamber. Also, a plasma gas tube is in fluid communication with the discharge chamber and provides a plasma gas thereto. Accordingly, the plasma gas can be used to maintain microplasma discharge between the electrodes and the sample gas can be introduced into the microplasma discharge. A spectrometer optically connected to the handheld/portable detector is used to measure the radiation emitted by the sample gas when subjected to the microplasma discharge.

  10. Note: Characterization of the plasma parameters of a capillary discharge-produced plasma channel waveguide to guide an intense laser pulse

    SciTech Connect

    Higashiguchi, Takeshi; Yugami, Noboru; Hikida, Masafumi; Terauchi, Hiromitsu; Bai Jinxiang; Kikuchi, Takashi; Tao Yezheng

    2010-04-15

    We demonstrated the production of an optical waveguide in a capillary discharge-produced plasma using a cylindrical capillary. Plasma parameters of its waveguide were characterized by use of both a Nomarski laser interferometer and a hydrogen plasma line spectrum. A space-averaged maximum temperature of 3.3 eV with electron densities of the order of 10{sup 17} cm{sup -3} was observed at a discharge time of 150 ns and a maximum discharge current of 400 A. An ultrashort, intense laser pulse was guided by use of this plasma channel.

  11. Factors related to sinus rhythm at discharge after radiofrequency ablation of permanent atrial fibrillation in patients undergoing mitral valve surgery.

    PubMed

    Rostagno, Carlo; Gelsomino, Sandro; Capecchi, Irene; Rossi, Alessandra; Montesi, Gian Franco; Stefàno, Pier Luigi

    2016-04-01

    Late recovery of sinus rhythm is unusual in patients with permanent AF treated by (radiofrequency) RF maze procedure during mitral valve surgery. Identification of clinical and instrumental preoperative factors predictive of early success of RF ablation in patients with permanent AF undergoing mitral valve surgery may improve selection of subjects to obtain long-term results. Hundred and thirty consecutive patients with permanent AF and mitral valve disease underwent modified RF maze procedure during concomitant mitral valve surgery. Rheumatic valve disease (61 pts) and mitral valve prolapse (41 pts) were the more common aetiology of valve abnormalities. Mitral valve replacement was performed in 54 % of patients and mitral valve repair in the remaining 46 %. Four patients died after surgery. At discharge, 87 patients (69 %) were in sinus rhythm (group 1) and 43 patients in AF persisted (group 2). At an average 24-month follow-up, sinus rhythm was present in 67 % of patients, and 33 % were in atrial fibrillation. In this period, late recovery of sinus rhythm was observed only in five patients, while eight discharged in sinus rhythm developed again atrial fibrillation. Among preoperative parameters at univariate analysis female sex, atrial fibrillation >24 months, left atrial diameter >54 mm, left atrial area >24 cm(2), rheumatic valve disease and NYHA class were associated with persistence of AF. At Cox regression multivariate analysis, increased left atrial area (OR 1.07 per unit increase-95 % CI 1.01-1.131) and rheumatic aetiology of valve disease (OR 4.52, 95 % CI 1.65-12.4) were associated with persistence of AF at hospital discharge. Persistence of AF after RF ablation in patients undergoing mitral valve surgery is related to aetiology, e.g. rheumatic valve disease, and to increasing left atrial diameter. Due to low rate of late recovery of sinus rhythm, indication to RF ablation associated with MV surgery should be carefully considered in patients with large

  12. Ozone generation in a kHz-pulsed He-O2 capillary dielectric barrier discharge operated in ambient air

    NASA Astrophysics Data System (ADS)

    Sands, Brian L.; Ganguly, Biswa N.

    2013-12-01

    The generation of reactive oxygen species using nonequilibrium atmospheric pressure plasma jet devices has been a subject of recent interest due to their ability to generate localized concentrations from a compact source. To date, such studies with plasma jet devices have primarily utilized radio-frequency excitation. In this work, we characterize ozone generation in a kHz-pulsed capillary dielectric barrier discharge configuration comprised of an active discharge plasma jet operating in ambient air that is externally grounded. The plasma jet flow gas was composed of helium with an admixture of up to 5% oxygen. A unipolar voltage pulse train with a 20 ns pulse risetime was used to drive the discharge at repetition rates between 2-25 kHz. Using UVLED absorption spectroscopy centered at 255 nm near the Hartley-band absorption peak, ozone was detected over 1 cm from the capillary axis. We observed roughly linear scaling of ozone production with increasing pulse repetition rate up to a "turnover frequency," beyond which ozone production steadily dropped and discharge current and 777 nm O(5P→5S°) emission sharply increased. The turnover in ozone production occurred at higher pulse frequencies with increasing flow rate and decreasing applied voltage with a common energy density of 55 mJ/cm3 supplied to the discharge. The limiting energy density and peak ozone production both increased with increasing O2 admixture. The power dissipated in the discharge was obtained from circuit current and voltage measurements using a modified parallel plate dielectric barrier discharge circuit model and the volume-averaged ozone concentration was derived from a 2D ozone absorption measurement. From these measurements, the volume-averaged efficiency of ozone production was calculated to be 23 g/kWh at conditions for peak ozone production of 41 mg/h at 11 kV applied voltage, 3% O2, 2 l/min flow rate, and 13 kHz pulse repetition rate, with 1.79 W dissipated in the discharge.

  13. Observations of soft X-ray emission and plasma dynamics of a compact capillary discharge operated in xenon

    SciTech Connect

    Valenzuela, J. C.; Wyndham, E. S.; Favre, M.; Chuaqui, H.

    2013-09-15

    We report observations of a low stored energy, low inductance compact capillary discharge operated in xenon. Even though the stored electrical energy is less than 1 J, significant output in the optical windows at 110 and 135 Å is measured. The soft X-ray emission is time-resolved and the conversion energy of the source is obtained. A lower bound to the conversion efficiency at 110 Å ± 2% and 135 Å ± 1% of 3.6% and 1.6% is obtained, respectively. The use of moiré-schlieren optical diagnostic allows the evolution of the line electron density. In particular, we observe a significant degree of compression in a tight on axis pinch as well as radial compression waves. The temporal evolution of the X-ray emission, which occurs during the current reversal and later, is discussed in relation to work in argon discharges and in relation to model calculations.

  14. Spectroscopically pure metal vapor source for highly charged ion spectroscopy and capillary discharge soft x-ray lasers.

    PubMed

    Tomasel, F G; Shlyaptsev, V N; Rocca, J J

    2008-01-01

    We describe a compact, pulsed metal vapor source used for the production of dense plasma columns of interest for both soft x-ray laser research and spectroscopy of highly ionized plasmas. The source generates spectroscopically pure cadmium vapor jets in a room-temperature environment by rapidly heating an electrode with a capacitive discharge. In the configuration described herein, the metal vapor jet produced by the source is axially injected into a fast (up to 15 kA/ ns), high current (up to 200 kA peak) capillary discharge to generate highly ionized cadmium plasma columns. Spectroscopic analysis of the discharge emission in the 12-25 nm spectral range evidences the dominance of Cu-like (CdXX) and Ni-like (CdXXI) lines and shows strong line emission at 13.2 nm from the 4d (1)S(0)-4p (1)P(1) laser transition of Ni-like Cd. Hydrodynamic/atomic physics simulations performed to describe the dynamics of the plasma column and compute the optimum discharge conditions for laser amplification are discussed.

  15. Endometrial ablation

    MedlinePlus

    Hysteroscopy-endometrial ablation; Laser thermal ablation; Endometrial ablation-radiofrequency; Endometrial ablation-thermal balloon ablation; Rollerball ablation; Hydrothermal ablation; Novasure ablation

  16. Numerical optimization of the electrical characteristics of an EUV laser on 3 p-3 s transition in neonlike argon ions in low-inductance capillary-type discharge

    NASA Astrophysics Data System (ADS)

    Burtsev, V. A.; Kalinin, N. V.; Vaganov, S. A.

    2017-01-01

    Electrical characteristics of low-inductance capillary-type discharge have been determined by numerical model calculations, which ensure high efficiency of energy supply to a plasma column with an aspect ratio of 1: 100. The EUV argon laser based on this discharge provides a gain of g + > 1 cm-1 on the operating transition and ensures single-pass spontaneous lasing with g + l > 25 (where l is the active medium length).

  17. High excitation of the species in nitrogen-aluminum plasma generated by electron cyclotron resonance microwave discharge of N2 gas and pulsed laser ablation of Al target

    NASA Astrophysics Data System (ADS)

    Liang, Peipei; Li, Yanli; Cai, Hua; You, Qinghu; Yang, Xu; Huang, Feiling; Sun, Jian; Xu, Ning; Wu, Jiada

    2014-11-01

    A reactive nitrogen-aluminum plasma generated by electron cyclotron resonance (ECR) microwave discharge of N2 gas and pulsed laser ablation of an Al target is characterized spectroscopically by time-integrated and time-resolved optical emission spectroscopy (OES). The vibrational and rotational temperatures of N2 species are determined by spectral simulation. The generated plasma strongly emits radiation from a variety of excited species including ambient nitrogen and ablated aluminum and exhibits unique features in optical emission and temperature evolution compared with the plasmas generated by a pure ECR discharge or by the expansion of the ablation plume. The working N2 gas is first excited by ECR discharge and the excitation of nitrogen is further enhanced due to the fast expansion of the aluminum plume induced by target ablation, while the excitation of the ablated aluminum is prolonged during the plume expansion in the ECR nitrogen plasma, resulting in the formation of strongly reactive nitrogen-aluminum plasma which contains highly excited species with high vibrational and rotational temperatures. The enhanced intensities and the prolonged duration of the optical emissions of the combined plasma would provide an improved analytical capability for spectrochemical analysis.

  18. Catheter ablation.

    PubMed

    Fromer, M; Shenasa, M

    1991-02-01

    Catheter ablation is gaining increasing interest for the therapy of symptomatic, sustained arrhythmias of various origins. The scope of this review is to give an overview of the biophysical aspects and major characteristics of some of the most widely used energy sources in catheter ablation, e.g., the discharge of conventional defibrillators, modified defibrillators, laser light, and radiofrequency current application. Results from animal studies are considered to explain the basic mechanisms of catheter ablation. The recent achievements with the use of radiofrequency current to modify or ablate cardiac conduction properties are outlined in more detail.

  19. Studies on the Application of High Voltage Discharge Ionization and Ablation in Supersonic-Jets for the Generation of Intense Cluster Ion Beams.

    NASA Astrophysics Data System (ADS)

    Brock, Ansgar

    Glow discharge and pulsed capacitor discharge ionization in supersonic expansions were investigated for the production of intense beams of molecular cluster ions from seeded and ablated compounds. A low cost high voltage high current pulser based on a triggered spark gap switch is described as a mean for ionization and ablation. Besides, details of the molecular beam apparatus and modified pulsed valve are given. Cluster cations rm (Ar)_ {n}^+, rm (CO_2) _{n}^{+}, rm (C_6H_6)_{n}^+ and rm (H_2O)_{n }^+ were produced by pulsed capacitor discharge ionization in the expansion region of a seeded free-jet. The observed cluster mass spectra (CMS) for Ar, rm C_6H_6 and H _2O show the characteristic features (magic numbers) of electron beam and photo ionized clusters under molecular flow conditions. Indications for the presence of magic numbers in the CMS of {(CO _2)_{n}^+} cluster ions at n = 20, 26, 30 and 34 similar to those found for rare gas clusters have been found. Cationic metal ligand complexes Cu(Toluene) _{rm n}^+, Cu(Acetone) _{rm n}^+, Cu(Methanol)_{rm n}^+ , Cu(Ethylether)_{rm n }^+, Cu(Water)_{ rm n}^+, Al(Water)_ {rm n}^+ were synthesized by ablation of the metal from metallic discharge electrodes in a discharge gas mixture of helium seeded with the ligand of choice. The CMS of the expanded plasmas show little background ion signal besides the metal-ligand species. Charge exchange processes in the expansion guarantee high ionization yields of the desired species and account for low backgrounds. Changes in the successive binding energy of Cu(Water)_ {rm n}^+ clusters n = 1-4 are clearly observed in the CMS as step formation. A similar pattern found in the Cu(Acetone)_{ rm n}^+ CMS suggests the same trend in the successive binding energy as known for water. Ablation from a Cr(acac)_3 in a copper matrix was employed for the synthesis of Cr(Acetone) _{rm n}^+ and Cr(Benzene)^+ complexes demonstrating the ability to use nonconducting compounds as a metal source

  20. Formation of diatomic molecular radicals in reactive nitrogen-carbon plasma generated by electron cyclotron resonance discharge and pulsed laser ablation

    SciTech Connect

    Liang, Peipei; Li, Yanli; You, Qinghu; Cai, Hua; Yang, Xu; Sun, Jian; Xu, Ning; Wu, Jiada

    2014-04-15

    The reactive nitrogen-carbon plasma generated by electron cyclotron resonance (ECR) microwave discharge of N{sub 2} gas and pulsed laser ablation of a graphite target was characterized spectroscopically by time-integrated and time-resolved optical emission spectroscopy with space resolution for a study of gas-phase reactions and molecular radical formation in the plasma. The plasma exhibits very high reactivity compared with the plasma generated solely by ECR discharge or by pulsed laser ablation and contains highly excited species originally present in the ambient gaseous environment and directly ablated from the target as well as formed as the products of gas-phase reactions occurring in the plasma. The space distribution and the time evolution of the plasma emission give an access to the gas-phase reactions for the formation of C{sub 2} and CN radicals, revealing that C{sub 2} radicals are formed mainly in the region near the target while CN radicals can be formed in a much larger region not only in the vicinity of the target, but especially in the region near a substrate far away from the target.

  1. Formation of diatomic molecular radicals in reactive nitrogen-carbon plasma generated by electron cyclotron resonance discharge and pulsed laser ablation

    NASA Astrophysics Data System (ADS)

    Liang, Peipei; Li, Yanli; You, Qinghu; Cai, Hua; Yang, Xu; Sun, Jian; Xu, Ning; Wu, Jiada

    2014-04-01

    The reactive nitrogen-carbon plasma generated by electron cyclotron resonance (ECR) microwave discharge of N2 gas and pulsed laser ablation of a graphite target was characterized spectroscopically by time-integrated and time-resolved optical emission spectroscopy with space resolution for a study of gas-phase reactions and molecular radical formation in the plasma. The plasma exhibits very high reactivity compared with the plasma generated solely by ECR discharge or by pulsed laser ablation and contains highly excited species originally present in the ambient gaseous environment and directly ablated from the target as well as formed as the products of gas-phase reactions occurring in the plasma. The space distribution and the time evolution of the plasma emission give an access to the gas-phase reactions for the formation of C2 and CN radicals, revealing that C2 radicals are formed mainly in the region near the target while CN radicals can be formed in a much larger region not only in the vicinity of the target, but especially in the region near a substrate far away from the target.

  2. Discharge-pumped XUV source

    NASA Astrophysics Data System (ADS)

    Schmidt, Jiri; Kolacek, Karel; Straus, Jaroslav; Frolov, Oleksandr

    2016-09-01

    We have built two experimental devices (CAPEX and CAPEX-U) working as XUV sources, which are based on the fast, pinching capillary discharge. On both these devices we have observed lasing at 46.9 nm (Ne-like Ar line). However, besides lasing at the above mentioned relatively long wavelength, they are also used for testing a possibility of amplification at the wavelengths below 20 nm that have more practical applications. Particularly, at present nitrogen-filled capillary (?4 mm x 90 mm) discharge is studied for the development of XUV (soft X-ray) laser based on recombination pumping scheme: the fully stripped nitrogen nuclei recombine to hydrogen-like atoms, where Balmer-alpha transition (wavelength 13.4 nm) is - according to theoretical predictions - capable of creating population inversion. The modified electrical parameters (peak current 60 kA with quarter period of 45 ns) meet the necessary theoretical conditions. The only question remains, if suitable pre-pulse can suppress the capillary-wall-ablation, which in all presently known cases has quashed the amplification. In this paper the recent results obtained from both these discharge systems (argon-, nitrogen-filled capillaries) will be presented. Acknowledgement: This work was performed under auspices and with the support of the Grant Agency of the Czech Republic (Contract 14-29772S) and of the Ministry of Education, Youth, and Sports of the Czech Republic (INGO contract LG15013).

  3. The role of the gas/plasma plume and self-focusing in a gas-filled capillary discharge waveguide for high-power laser-plasma applications

    SciTech Connect

    Ciocarlan, C.; Wiggins, S. M.; Islam, M. R.; Ersfeld, B.; Abuazoum, S.; Wilson, R.; Aniculaesei, C.; Welsh, G. H.; Vieux, G.; Jaroszynski, D. A.

    2013-09-15

    The role of the gas/plasma plume at the entrance of a gas-filled capillary discharge plasma waveguide in increasing the laser intensity has been investigated. Distinction is made between neutral gas and hot plasma plumes that, respectively, develop before and after discharge breakdown. Time-averaged measurements show that the on-axis plasma density of a fully expanded plasma plume over this region is similar to that inside the waveguide. Above the critical power, relativistic and ponderomotive self-focusing lead to an increase in the intensity, which can be nearly a factor of 2 compared with the case without a plume. When used as a laser plasma wakefield accelerator, the enhancement of intensity can lead to prompt electron injection very close to the entrance of the waveguide. Self-focusing occurs within two Rayleigh lengths of the waveguide entrance plane in the region, where the laser beam is converging. Analytical theory and numerical simulations show that, for a density of 3.0 × 10{sup 18} cm{sup −3}, the peak normalized laser vector potential, a{sub 0}, increases from 1.0 to 1.85 close to the entrance plane of the capillary compared with a{sub 0} = 1.41 when the plume is neglected.

  4. Analysis of trace amounts of carbon dioxide, oxygen and carbon monoxide in nitrogen using dual capillary columns and a pulsed discharge helium ionisation detector.

    PubMed

    Janse van Rensburg, M; Botha, A; Rohwer, E

    2007-10-05

    Gas mixtures of trace amounts of carbon dioxide (CO(2)), dioxygen (O(2)), and carbon monoxide (CO) in dinitrogen (N(2)) were separated and quantified using parallel dual capillary columns and pulsed discharge helium ionisation detection (PDHID). The detection limits (9 x 10(-9) mol mol(-1) for CO(2), 7 x 10(-9) mol mol(-1) for O(2) and 37 x 10(-9) mol mol(-1) for CO) were lower than those reported previously for similar methods. Uncertainties were calculated and results were validated by comparison of the CO and CO(2) results with those obtained using conventional methods. The method was also used to analyse nitrogen, carbon dioxide and carbon monoxide in oxygen.

  5. Direct quantification of chemical warfare agents and related compounds at low ppt levels: comparing active capillary dielectric barrier discharge plasma ionization and secondary electrospray ionization mass spectrometry.

    PubMed

    Wolf, Jan-Christoph; Schaer, Martin; Siegenthaler, Peter; Zenobi, Renato

    2015-01-06

    A novel active capillary dielectric barrier discharge plasma ionization (DBDI) technique for mass spectrometry is applied to the direct detection of 13 chemical warfare related compounds, including sarin, and compared to secondary electrospray ionization (SESI) in terms of selectivity and sensitivity. The investigated compounds include an intact chemical warfare agent and structurally related molecules, hydrolysis products and/or precursors of highly toxic nerve agents (G-series, V-series, and "new" nerve agents), and blistering and incapacitating warfare agents. Well-defined analyte gas phase concentrations were generated by a pressure-assisted nanospray with consecutive thermal evaporation and dilution. Identification was achieved by selected reaction monitoring (SRM). The most abundant fragment ion intensity of each compound was used for quantification. For DBDI and SESI, absolute gas phase detection limits in the low ppt range (in MS/MS mode) were achieved for all compounds investigated. Although the sensitivity of both methods was comparable, the active capillary DBDI sensitivity was found to be dependent on the applied AC voltage, thus enabling direct tuning of the sensitivity and the in-source fragmentation, which may become a key feature in terms of field applicability. Our findings underline the applicability of DBDI and SESI for the direct, sensitive detection and quantification of several CWA types and their degradation products. Furthermore, they suggest the use of DBDI in combination with hand-held instruments for CWAs on-site monitoring.

  6. Time-resolved characterization of a filamentary argon discharge at atmospheric pressure in a capillary using emission and absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Schröter, Sandra; Pothiraja, Ramasamy; Awakowicz, Peter; Bibinov, Nikita; Böke, Marc; Niermann, Benedikt; Winter, Jörg

    2013-11-01

    An argon/nitrogen (0.999/0.001) filamentary pulsed discharge operated at atmospheric pressure in a quartz tube is characterized using voltage-current measurements, microphotography, optical emission spectroscopy (OES) and absorption spectroscopy. Nitrogen is applied as a sensor gas for the purpose of OES diagnostic. The density of argon metastable atoms Ar(3P2) is determined using tunable diode laser absorption spectroscopy (TDLAS). Using a plasma chemical model the measured OES data are applied for the characterization of the plasma conditions. Between intense positive pulses the discharge current oscillates with a damped amplitude. It is established that an electric current flows in this discharge not only through a thin plasma filament that is observed in the discharge image but also through the whole cross section of the quartz tube. A diffuse plasma fills the quartz tube during a time between intense current pulses. Ionization waves are propagating in this plasma between the spike and the grounded area of the tube producing thin plasma channels. The diameter of these channels increases during the pause between the propagation of ionization waves probably because of thermal expansion and diffusion. Inside the channels electron densities of ˜2 × 1013 cm-3, argon metastable densities ˜1014 cm-3 and a reduced electric field about 10 Td are determined.

  7. Nanometer-scale ablation using focused, coherent extreme ultraviolet/soft x-ray light

    SciTech Connect

    Menoni, Carmen S; Rocca, Jorge J; Vaschenko, Georgiy; Bloom, Scott; Anderson, Erik H; Chao, Weilun; Hemberg, Oscar

    2011-04-26

    Ablation of holes having diameters as small as 82 nm and having clean walls was obtained in a poly(methyl methacrylate) on a silicon substrate by focusing pulses from a Ne-like Ar, 46.9 nm wavelength, capillary-discharge laser using a freestanding Fresnel zone plate diffracting into third order is described. Spectroscopic analysis of light from the ablation has also been performed. These results demonstrate the use of focused coherent EUV/SXR light for the direct nanoscale patterning of materials.

  8. Time-resolved study of the extreme-ultraviolet emission and plasma dynamics of a sub-Joule, fast capillary discharge

    NASA Astrophysics Data System (ADS)

    Valenzuela, J. C.; Wyndham, E. S.; Favre, M.

    2015-08-01

    In this work, we discuss experimental observations on the dynamics of a fast, low energy capillary discharge when operated in argon and its properties as an intense source of extreme-ultraviolet (EUV) radiation. The discharge pre-ionization and self-triggering were accomplished by the use of the hollow cathode effect. This allowed a compact size and low inductance discharge with multi-kA current level and a quarter-period of ˜10 ns at sub-Joule energy level. We used the novel moiré and schlieren diagnostics with a 12 ps laser to obtain the time evolution of the line electron density and to study the plasma dynamics. EUV spectroscopy and filtered diodes were also implemented to estimate the plasma temperature and density throughout the evolution of the discharge. EUV source size was measured by using a filtered slit-wire camera. We observed that EUV emission starts from a compressed plasma on axis during the second quarter-period of the current and continues until the fifth quarter-period. Ionization levels from Ar VII to X were observed. By comparing the EUV emission spectra with synthetic spectra, we found that at the onset of emission (˜7 ns), the plasma is well fitted by a single Maxwellian electron distribution function with Te ˜ 12 eV and ne ˜ 1017 cm-3. Close to peak emission (˜13 ns), plasma temperature and density increase to ˜20 eV and ne ˜ 1018 cm-3, respectively. However, in order to successfully match the experimental data, a two component electron distribution function was necessary. Later in time, a smaller fraction in the high energy component and higher temperature suggests homogenization of the plasma. The moiré and schlieren diagnostics showed multiple radial compression-waves merging on axis throughout the discharge; they are an important heating mechanism that leads to a period of severe turbulence at peak EUV emission. It was also observed that emission ceases when the axial maximum of the electron density collapses.

  9. Time-resolved study of the extreme-ultraviolet emission and plasma dynamics of a sub-Joule, fast capillary discharge

    SciTech Connect

    Valenzuela, J. C.; Wyndham, E. S.; Favre, M.

    2015-08-15

    In this work, we discuss experimental observations on the dynamics of a fast, low energy capillary discharge when operated in argon and its properties as an intense source of extreme-ultraviolet (EUV) radiation. The discharge pre-ionization and self-triggering were accomplished by the use of the hollow cathode effect. This allowed a compact size and low inductance discharge with multi-kA current level and a quarter-period of ∼10 ns at sub-Joule energy level. We used the novel moiré and schlieren diagnostics with a 12 ps laser to obtain the time evolution of the line electron density and to study the plasma dynamics. EUV spectroscopy and filtered diodes were also implemented to estimate the plasma temperature and density throughout the evolution of the discharge. EUV source size was measured by using a filtered slit-wire camera. We observed that EUV emission starts from a compressed plasma on axis during the second quarter-period of the current and continues until the fifth quarter-period. Ionization levels from Ar VII to X were observed. By comparing the EUV emission spectra with synthetic spectra, we found that at the onset of emission (∼7 ns), the plasma is well fitted by a single Maxwellian electron distribution function with T{sub e} ∼ 12 eV and n{sub e} ∼ 10{sup 17 }cm{sup −3}. Close to peak emission (∼13 ns), plasma temperature and density increase to ∼20 eV and n{sub e} ∼ 10{sup 18 }cm{sup −3}, respectively. However, in order to successfully match the experimental data, a two component electron distribution function was necessary. Later in time, a smaller fraction in the high energy component and higher temperature suggests homogenization of the plasma. The moiré and schlieren diagnostics showed multiple radial compression-waves merging on axis throughout the discharge; they are an important heating mechanism that leads to a period of severe turbulence at peak EUV emission. It was also observed that emission

  10. Capillary Hemangioma

    MedlinePlus

    ... Why do capillary hemangiomas on the eyelids cause vision problems? Capillary Hemangiomas of the eyelid can cause ... a capillary hemangioma in the eye socket cause vision problems? A capillary hemangioma in the eye socket ( ...

  11. Gas-Filled Capillary Model

    NASA Astrophysics Data System (ADS)

    Steinhauer, L. C.; Kimura, W. D.

    2006-11-01

    We have developed a 1-D, quasi-steady-state numerical model for a gas-filled capillary discharge that is designed to aid in selecting the optimum capillary radius in order to guide a laser beam with the required intensity through the capillary. The model also includes the option for an external solenoid B-field around the capillary, which increases the depth of the parabolic density channel in the capillary, thereby allowing for propagation of smaller laser beam waists. The model has been used to select the parameters for gas-filled capillaries to be utilized during the Staged Electron Laser Acceleration — Laser Wakefield (STELLA-LW) experiment.

  12. Long-lived plasma and fast quenching of N2(C3Π u ) by electrons in the afterglow of a nanosecond capillary discharge in nitrogen

    NASA Astrophysics Data System (ADS)

    Lepikhin, N. D.; Klochko, A. V.; Popov, N. A.; Starikovskaia, S. M.

    2016-08-01

    Quenching of electronically excited nitrogen state, {{\\text{N}}2}≤ft({{\\text{C}}3}{{\\Pi}u},{{v}\\prime}=0\\right) , in the afterglow of nanosecond capillary discharge in pure nitrogen is studied. It is found experimentally that an additional collisional mechanism appears and dominates at high specific deposited energies leading to the anomalously fast quenching of the {{\\text{N}}2}≤ft({{\\text{C}}3}{{\\Pi}u}\\right) in the afterglow. On the basis of obtained experimental data and of the analysis of possible quenching agents, it is concluded that the anomalously fast deactivation of the {{\\text{N}}2}≤ft({{\\text{C}}3}{{\\Pi}u}\\right) can be explained by quenching by electrons. Long-lived plasma at time scale of hundreds nanoseconds after the end of the pulse is observed. High electron densities, about 1014 cm-3 at 27 mbar, are sustained by reactions of associative ionization. Kinetic 1D numerical modeling and comparison of calculated results with experimentally measured electric fields in the second high-voltage pulse 250 ns after the initial pulse, and electron density measurements in the afterglow confirm the validity of the suggested mechanism.

  13. Focusing and photon flux measurements of the 2.88-nm radiation at the sample plane of the soft x-ray microscope, based on capillary discharge source

    NASA Astrophysics Data System (ADS)

    Nawaz, M. Fahad; Jancarek, Alexandr; Nevrkla, Michal; Wachulak, Przemyslaw; Limpouch, Jiri; Pina, Ladislav

    2015-05-01

    Feasibility measurements leading to the development of a Soft X-ray (SXR) microscopy setup, based on capillary discharge XUV source is presented. Here the Z-pinching plasma is acting as a source of XUV radiation, emitting incoherent radiation in the "water-window" (λ = 2.3 - 4.4 nm) region of interest (natural contrast between the carbon and oxygen edges).This soft X-ray microscopy setup will realize imaging of the biological objects with high spatial resolution. The 2.88 nm radiation line is filtered out from the water-window band, and is focused by an axi-symmetric ellipsoidal mirror, coated with nickle. The focussed spot size is measured and reported. Flux measurements for the available number of photons (photons/pulse) at the sample plane has been carried out with AXUV PIN diode at the sample plane (slightly out of focus). For imaging, a fresnel zone plate lens will be used as an objective. The overall compact transmission SXR microscopy setup design is presented.

  14. Plasma Interactions in Laser Irradiated Semi-Cylindrical Cavities Studied with Soft X-Ray Interferometry Using a Capillary Discharge Laser

    SciTech Connect

    Purvis, M A; Grava, J; Filevich, J; Marconi, M; Rocca, J J; Moon, S J; Dunn, J; Nilsen, J; Shlyaptsev, V N; Jankowska, E

    2007-09-19

    Soft x-ray interferometry was used to measure the evolution of dense converging plasmas created by laser irradiation of 500 {micro}m diameter semi-cylindrical carbon targets. Optical laser pulses with an intensity of {approx} 1 x 10{sup 12} W cm{sup -2} and 120 ps duration were used to heat the surface of the cavities. The dense plasma formed expands from the walls converging slightly off the semi-cylinder's axis, giving rise to a bright localized high density plasma region. A sequence of electron density maps were measured using a 46.9 nm wavelength tabletop capillary discharge soft x-ray laser probe and a amplitude division interferometer based on diffraction gratings. The measured density profiles are compared with simulations conducted using the multi-dimensional hydrodynamic code HYDRA. The benchmarked model was then used to simulate particle trajectories which reveal that the increase in electron density near the axis is mainly the result of the convergence of plasma that originated at the bottom of the groove during laser irradiation.

  15. Plume collimation for laser ablation electrospray ionization mass spectrometry

    DOEpatents

    Vertes, Akos; Stolee, Jessica A.

    2016-06-07

    In various embodiments, a device may generally comprise a capillary having a first end and a second end; a laser to emit energy at a sample in the capillary to ablate the sample and generate an ablation plume in the capillary; an electrospray apparatus to generate an electrospray plume to intercept the ablation plume to produce ions; and a mass spectrometer having an ion transfer inlet to capture the ions. The ablation plume may comprise a collimated ablation plume. The device may comprise a flow cytometer. Methods of making and using the same are also described.

  16. Plume collimation for laser ablation electrospray ionization mass spectrometry

    DOEpatents

    Vertes, Akos; Stolee, Jessica A.

    2014-09-09

    In various embodiments, a device may generally comprise a capillary having a first end and a second end; a laser to emit energy at a sample in the capillary to ablate the sample and generate an ablation plume in the capillary; an electrospray apparatus to generate an electrospray plume to intercept the ablation plume to produce ions; and a mass spectrometer having an ion transfer inlet to capture the ions. The ablation plume may comprise a collimated ablation plume. The device may comprise a flow cytometer. Methods of making and using the same are also described.

  17. Highly efficient pulsed power supply system with a two-stage LC generator and a step-up transformer for fast capillary discharge soft x-ray laser at shorter wavelength.

    PubMed

    Sakai, Yusuke; Takahashi, Shnsuke; Komatsu, Takanori; Song, Inho; Watanabe, Masato; Hotta, Eiki

    2010-01-01

    Highly efficient and compact pulsed power supply system for a capillary discharge soft x-ray laser (SXRL) has been developed. The system consists of a 2.2 microF two-stage LC inversion generator, a 2:54 step-up transformer, a 3 nF water capacitor, and a discharge section with a few tens of centimeter length capillary. Adoption of the pulsed transformer in combination with the LC inversion generator enables us to use only one gap switch in the circuit for charging the water capacitor up to about 0.5 MV. Furthermore, step-up ratio of a water capacitor voltage to a LC inversion generator initial charging voltage is about 40 with energy transfer efficiency of about 50%. It also leads to good reproducibility of a capillary discharge which is necessary for lasing a SXRL stably. For the study of the possibility of lasing a SXRL at shorter wavelength in a small laboratory scale, high-density and high-temperature plasma column suitable for the laser can be generated relatively easily with this system.

  18. Highly efficient pulsed power supply system with a two-stage LC generator and a step-up transformer for fast capillary discharge soft x-ray laser at shorter wavelength

    SciTech Connect

    Sakai, Yusuke; Takahashi, Shnsuke; Komatsu, Takanori; Song, Inho; Watanabe, Masato; Hotta, Eiki

    2010-01-15

    Highly efficient and compact pulsed power supply system for a capillary discharge soft x-ray laser (SXRL) has been developed. The system consists of a 2.2 {mu}F two-stage LC inversion generator, a 2:54 step-up transformer, a 3 nF water capacitor, and a discharge section with a few tens of centimeter length capillary. Adoption of the pulsed transformer in combination with the LC inversion generator enables us to use only one gap switch in the circuit for charging the water capacitor up to about 0.5 MV. Furthermore, step-up ratio of a water capacitor voltage to a LC inversion generator initial charging voltage is about 40 with energy transfer efficiency of about 50%. It also leads to good reproducibility of a capillary discharge which is necessary for lasing a SXRL stably. For the study of the possibility of lasing a SXRL at shorter wavelength in a small laboratory scale, high-density and high-temperature plasma column suitable for the laser can be generated relatively easily with this system.

  19. Transient Shock Formation of Pulsed Electrothermal Plasma Discharge Confined in an Extended Bore

    NASA Astrophysics Data System (ADS)

    Kim, Kyoungjin; Kwak, Ho Sang; Park, Joong-Youn

    An electrothermal gun possesses a great potential to be an efficient source of pulsed plasma discharge for nanomaterials production or thermal plasma spray coatings. A plasma discharge by intense pulsed power is numerically studied utilizing time-dependent gas dynamics equations which are solved by FCT (flux-corrected transport) algorithm in two-dimensional domain of the interior capillary bore region and the external region of extended bore. Plasma conditions at the bore exit, mass ablation of polycarbonate bore wall, and degree of ionization are determined at different levels of transient arc current profile. As a way to controlling the plasma discharge, the extended bore at the capillary exit is considered and the flow pattern of pulsed plasma discharge in the extended bore exhibit complex shock structure from slightly to highly underexpanded jet depending on the level of arc current profiles. Flow instability of oscillating Mach disk is found at higher level of arc current profile cases.

  20. The rotational spectrum of CuCCH(X̃  1Σ+): a Fourier transform microwave discharge assisted laser ablation spectroscopy and millimeter/submillimeter study.

    PubMed

    Sun, M; Halfen, D T; Min, J; Harris, B; Clouthier, D J; Ziurys, L M

    2010-11-07

    The pure rotational spectrum of CuCCH in its ground electronic state (X̃  (1)Σ(+)) has been measured in the frequency range of 7-305 GHz using Fourier transform microwave (FTMW) and direct absorption millimeter/submillimeter methods. This work is the first spectroscopic study of CuCCH, a model system for copper acetylides. The molecule was synthesized using a new technique, discharge assisted laser ablation spectroscopy (DALAS). Four to five rotational transitions were measured for this species in six isotopologues ((63)CuCCH, (65)CuCCH, (63)Cu(13)CCH, (63)CuC(13)CH, (63)Cu(13)C(13)CH, and (63)CuCCD); hyperfine interactions arising from the copper nucleus were resolved, as well as smaller splittings in CuCCD due to deuterium quadrupole coupling. Five rotational transitions were also recorded in the millimeter region for (63)CuCCH and (65)CuCCH, using a Broida oven source. The combined FTMW and millimeter spectra were analyzed with an effective Hamiltonian, and rotational, electric quadrupole (Cu and D) and copper nuclear spin-rotation constants were determined. From the rotational constants, an r(m)(2) structure for CuCCH was established, with r(Cu-C) = 1.8177(6) Å, r(C-C) = 1.2174(6) Å, and r(C-H) = 1.046(2) Å. The geometry suggests that CuCCH is primarily a covalent species with the copper atom singly bonded to the C≡C-H moiety. The copper quadrupole constant indicates that the bonding orbital of this atom may be sp hybridized. The DALAS technique promises to be fruitful in the study of other small, metal-containing molecules of chemical interest.

  1. The rotational spectrum of CuCCH(X~ 1Σ+): A Fourier transform microwave discharge assisted laser ablation spectroscopy and millimeter/submillimeter study

    NASA Astrophysics Data System (ADS)

    Sun, M.; Halfen, D. T.; Min, J.; Harris, B.; Clouthier, D. J.; Ziurys, L. M.

    2010-11-01

    The pure rotational spectrum of CuCCH in its ground electronic state (X˜ Σ1+) has been measured in the frequency range of 7-305 GHz using Fourier transform microwave (FTMW) and direct absorption millimeter/submillimeter methods. This work is the first spectroscopic study of CuCCH, a model system for copper acetylides. The molecule was synthesized using a new technique, discharge assisted laser ablation spectroscopy (DALAS). Four to five rotational transitions were measured for this species in six isotopologues (C63uCCH, C65uCCH, C63uC13CH, C63uCC13H, C63uC13C13H, and C63uCCD); hyperfine interactions arising from the copper nucleus were resolved, as well as smaller splittings in CuCCD due to deuterium quadrupole coupling. Five rotational transitions were also recorded in the millimeter region for C63uCCH and C65uCCH, using a Broida oven source. The combined FTMW and millimeter spectra were analyzed with an effective Hamiltonian, and rotational, electric quadrupole (Cu and D) and copper nuclear spin-rotation constants were determined. From the rotational constants, an rm(2) structure for CuCCH was established, with rCuC=1.8177(6) Å, rCC=1.2174(6) Å, and rCH=1.046(2) Å. The geometry suggests that CuCCH is primarily a covalent species with the copper atom singly bonded to the CCH moiety. The copper quadrupole constant indicates that the bonding orbital of this atom may be sp hybridized. The DALAS technique promises to be fruitful in the study of other small, metal-containing molecules of chemical interest.

  2. Capillary sample

    MedlinePlus

    ... repeat the test with blood drawn from a vein. Alternative Names Blood sample - capillary; Fingerstick; Heelstick Images Phenylketonuria test Phenylketonuria test Capillary sample References Garza ...

  3. Multi-GeV electron beams from capillary discharge guided sub-petawatt class laser pulses in the self-trapping regime

    NASA Astrophysics Data System (ADS)

    Leemans, Wim

    2014-10-01

    Laser plasma accelerators (LPAs) can produce acceleration gradients on the order of tens to hundreds of GV/m, making them attractive as compact particle accelerators. During the past decade, quasi-monochromatic electron beams at the 1 GeV energy level have been produced using laser pulses at the 40-50 TW peak power level. With the availability of petawatt class lasers, beams up to 2 GeV have been produced from 7 cm long gas cells at UT Austin using 150 J laser pulses and at the 1 GeV level with tails extending to 3 GeV at the GIST facility in Korea. In this talk we present experimental results using the 1 Hz petawatt class BELLA laser at LBNL of the generation of multi-GeV electron beams with center energy up to 4.2 GeV, 6% rms energy spread, charge approximately 10 pC and an rms divergence around 0.3 mrad. The beams were produced from 9 cm long capillary discharge waveguide structure with a plasma density of ~ 7 ×1017cm-3 , powered by laser pulses with peak power up to 0.3 PW. Preformed plasma waveguides allow the use of lower laser power compared to unguided plasma structures to achieve the same beam energy. Detailed comparison between experiment and simulation indicates the importance of the near-field laser transverse mode quality on guiding and acceleration in the LPA. By tuning the plasma density, regimes were found where laser beams with a top hat near-field profile were guided well, and where high energy electron beams can be produced, with narrow divergence [ <0.8 mrad (FWHM)], and relatively small integrated energy spread (<10%). Provided that the slice energy spread and emittance are sufficiently low, electron beams with this energy could power x-ray free electron lasers. Future experiments will aim at increasing the beam energy to the 10 GeV level. Work supported by Office of Science, Office of HEP, US DOE Contract DE-AC02-05CH11231.

  4. Enhanced Performance of Electrothermal Plasma Sources as Fusion Pellet Injection Drivers and Space Based Mini-Thrusters via Extension of a Flattop Discharge Current

    NASA Astrophysics Data System (ADS)

    Leigh Winfrey, A.; Abd Al-Halim, Mohamed A.; Saveliev, Alexei V.; Gilligan, John G.; Bourham, Mohamed A.

    2013-06-01

    Electrothermal plasma sources have been introduced as a method to propel frozen hydrogenic pellets for fueling of future magnetic fusion reactors. These sources are also useful as mini-thrusters in space shuttles, pre-injectors in hypervelocity launchers and igniters in electrothermal-chemical Guns. The source is a capillary discharge that generates the plasma from the ablation of a liner in an ablation-dominated regime, or from the flow of gas into the capillary in an ablation-free regime. Most electrothermal plasma sources uses pulse power delivery system with a pulse length in the range of 100 μs with FWHM of 50 μs. This research is a computational study on the effect of extending the top of the discharge current pulse to the range of 1,000 μs on the source exit parameter to achieve higher pressures and better exit velocities. Calculations using 0.4 cm diameter, 9.0 cm length Lexan polycarbonate capillary source, using ideal and nonideal plasma models, show that extended flattop pulses at fixed amplitude produce more ablated mass which scales linearly with increased pulse length, however, other plasma parameters remain almost constant. Results suggest that quasi-steady state operation of an electrothermal plasma source may provide constant exit pressure and velocity for pellet injectors for future magnetic fusion reactors deep fueling.

  5. EUV nanosecond laser ablation of silicon carbide, tungsten and molybdenum

    NASA Astrophysics Data System (ADS)

    Frolov, Oleksandr; Kolacek, Karel; Schmidt, Jiri; Straus, Jaroslav; Choukourov, Andrei; Kasuya, Koichi

    2015-09-01

    In this paper we present results of study interaction of nanosecond EUV laser pulses at wavelength of 46.9 nm with silicon carbide (SiC), tungsten (W) and molybdenum (Mo). As a source of laser radiation was used discharge-plasma driver CAPEX (CAPillary EXperiment) based on high current capillary discharge in argon. The laser beam is focused with a spherical Si/Sc multilayer-coated mirror on samples. Experimental study has been performed with 1, 5, 10, 20 and 50 laser pulses ablation of SiC, W and Mo at various fluence values. Firstly, sample surface modification in the nanosecond time scale have been registered by optical microscope. And the secondly, laser beam footprints on the samples have been analyzed by atomic-force microscope (AFM). This work supported by the Czech Science Foundation under Contract GA14-29772S and by the Grant Agency of the Ministry of Education, Youth and Sports of the Czech Republic under Contract LG13029.

  6. Demonstration of gain saturation and double-pass amplification of a 69.8  nm laser pumped by capillary discharge.

    PubMed

    Zhao, Yongpeng; Liu, Tao; Zhang, Wenhong; Li, Wei; Cui, Huaiyu

    2016-08-15

    With a 45-cm-long capillary, we obtained a saturated 69.8 nm laser with a gain coefficient of 0.4  cm-1 and a gain length product of 18. In order to increase the laser energy further, a double-pass amplification of the 69.8 nm laser was first realized with a SiC mirror without a coating. With a half cavity, the effective plasma column length and the effective gain length product can reach 84 cm and 33.7, respectively. The amplitude of a laser pulse for double-pass amplification is 9 times larger than that for single-pass amplification. In addition, the full width at half-maximum (FWHM) pulse width of a laser pulse and FWHM divergence for single-pass amplification are 1.4 ns and 0.5 mrad, respectively, which increase to 2.2 ns and 3.4 mrad for double-pass amplification.

  7. Thermal ablation.

    PubMed

    Webb, Heather; Lubner, Meghan G; Hinshaw, J Louis

    2011-04-01

    Image-guided tumor ablation refers to a group of treatment modalities that have emerged during the past 2 decades as important tools in the treatment of a wide range of tumors throughout the body. Although most widely recognized in the treatment of hepatic and renal malignancies, the role of thermal ablation has expanded to include lesions of the lung, breast, prostate, bone, as well as other organs and its clinical applications continue to increase. In the following article, we discuss the major thermal ablation modalities, their respective strengths and weaknesses, potential complications and how to avoid them, as well as possible future applications.

  8. Catheter Ablation

    MedlinePlus

    ... you during the procedure. Machines will measure your heart’s activity. All types of ablation require cardiac catheterization to place flexible tubes, or catheters, inside your heart to make the scars. Your doctor will clean ...

  9. Capillary electrophoresis.

    PubMed

    Compton, S W; Brownlee, R G

    1988-05-01

    While capillary electrophoresis, or historically related techniques, have been used for over a century, and recognition of the value of this separation methodology has certainly grown rapidly in the past few years, the technique has generally been used by analytical chemists, particularly in Europe and Japan, and small groups of researchers in the United States. Many of the basic instrumentation problems have been solved only relatively recently, and researchers using capillary electrophoresis are now turning their attention to studying specific applications which demonstrate the potential versatility of this electrophoretic technique. The appearance of standardized commercial instrumentation is imminent. With the availability of such technology, capillary electrophoresis will no longer be an academic curiosity, but rather a tool with the potential for routine separations of diverse samples of interest to analyst, researcher, and clinician.

  10. Gallbladder removal - laparoscopic - discharge

    MedlinePlus

    Cholecystectomy laparoscopic - discharge; Cholelithiasis - laparoscopic discharge; Biliary calculus - laparoscopic discharge; Gallstones - laparoscopic discharge; Cholecystitis - laparoscopic discharge

  11. Pellet ablation and ablation model development

    SciTech Connect

    Houlberg, W.A.

    1989-01-01

    A broad survey of pellet ablation is given, based primarily on information presented at this meeting. The implications of various experimental observations for ablation theory are derived from qualitative arguments of the physics involved. The major elements of a more complete ablation theory are then outlined in terms of these observations. This is followed by a few suggestions on improving the connections between theory and experimental results through examination of ablation data. Although this is a rather aggressive undertaking for such a brief (and undoubtedly incomplete) assessment, some of the discussion may help us advance the understanding of pellet ablation. 17 refs.

  12. Pancreatitis - discharge

    MedlinePlus

    Chronic pancreatitis - discharge; Pancreatitis - chronic - discharge; Pancreatic insufficiency - discharge; Acute pancreatitis - discharge ... fluids through an intravenous (IV) tube in your vein and nutrition through a feeding tube or IV. ...

  13. [Indications for catheter ablation of ventricular tachycardia].

    PubMed

    Deneke, T; Israel, C W; Krug, J; Nentwich, K; Müller, P; Mügge, A; Schade, A

    2013-09-01

    Ventricular tachyarrhythmias (VT) can cause sudden cardiac death. This can be prevented by an implantable cardioverter-defibrillator (ICD) but approximately 25% of patients with an ICD develop electrical storm (≥ 3 VTs within 24 hours) during the course of 4-5 years. This is a life-threatening event even in the presence of an ICD, particularly if incessant VT is present, and may significantly deteriorate the patient's psychological state if multiple shocks are discharged. Catheter ablation of VT has developed into a standard procedure in many specialized electrophysiology centers. Patients with hemodynamically stable and unstable VT are amendable to substrate-based ablation strategies. Catheter ablation can be performed as emergency procedure in patients with electrical storm as well as electively in patients with monomorphic VT stored in ICD memory. In patients with ischemic or non-ischemic cardiomyopathy, VT ablation is complementary to ICD implantation and can reduce the number of ventricular arrhythmia episodes and shocks and should be performed early. In patients with electrical storm, catheter ablation can acutely achieve rhythm stabilization and may improve prognosis in the long term. Further indications for catheter ablation exist in patients with idiopathic VT where catheter ablation represents a curative therapy, and in patients with symptomatic or asymptomatic frequent premature ventricular beats which may improve prognosis in patients with heart failure and cardiac resynchronization therapy.

  14. Analysis of Capillary Guided Laser Plasma Accelerator Experiments at LBNL

    SciTech Connect

    Nakamura, K.; Esarey, E.; Leemans, W. P.; Gonsalves, A. J.; Panasenko, D.; Toth, Cs.; Geddes, C. G. R.; Schroeder, C. B.; Lin, C.

    2009-01-22

    Laser wakefield acceleration experiments were carried out by using a hydrogen-filled capillary discharge waveguide. For a 15 mm long, 200 {mu}m diameter capillary, quasi-monoenergetic e-beams up to 300 MeV were observed. By de-tuning discharge delay from optimum guiding performance, self-trapping was found to be stabilized. For a 33 mm long, 300 {mu}m capillary, a parameter regime with high energy electron beams, up to 1 GeV, was found. In this regime, the electron beam peak energy was correlated with the amount of trapped electrons.

  15. RF micro-discharge thruster

    NASA Astrophysics Data System (ADS)

    Dunaevsky, Alexander; Fisch, Nathaniel

    2004-11-01

    Propulsion devices for spacecrafts with masses of several tens to one hundred kilograms are in an increasing demand. These devices should provide thrust of a few mN and specific impulse of about 1000 s at the total power consumption of several tens of W. In search of an alternative solution for lower power range, we investigated an rf discharge initiated in a sub-millimeter capillary fed by a gaseous propellant. In such a discharge, it is possible to heat plasma electrons up to temperatures of ˜ 20-30 eV. Steep density drop at the open end of the capillary should be a reason of the formation of a double layer, were the discharge ions are accelerated to energies of ˜5Te. A laboratory prototype demonstrated stable operation at the argon flow rate of 4-10 sccm. The discharge was powered by a 2 MHz rf generator. Power consumption of the discharge was about 16 W. Ionization rate was moderate due to nonoptimal electrode configuration, which resulted in the propellant utilization of 6-11%. Relatively wide plume angle of ˜130 degrees indicates that the acceleration region is placed outside the capillary and has a convex shape. Stability and parameters of the discharge depends on the material of the capillary channel. Among advantages of the rf micro-discharge thruster are simplicity, small size, and absence of cathode-neutralizer. Being optimized, the rf micro-discharge thruster seems very promising propulsion device for sub-mN thrust range.

  16. Xenon excimer emission from multicapillary discharges in direct current mode

    SciTech Connect

    Lee, Byung-Joon; Rahaman, Hasibur; Nam, Sang Hoon; Giapis, Konstantinos P.; Iberler, Marcus; Jacoby, Joachim; Frank, Klaus

    2011-08-15

    Microdischarges in xenon have been generated in a pressure range of 400-1013 mbar with a fixed flow rate of 100 sccm. These microdischarges are obtained from three metallic capillary tubes in series for excimer emission. Total discharge voltage is thrice as large as that of a single capillary discharge tube at current levels of up to 12 mA. Total spectral irradiance of vacuum ultraviolet (VUV) emission also increases significantly compared to that of the single capillary discharge. Further, the irradiance of the VUV emission is strongly dependent on pressure as well as the discharge current.

  17. Radiofrequency Ablation of Liver Tumors

    MedlinePlus

    ... Site Index A-Z Radiofrequency Ablation (RFA) of Liver Tumors Radiofrequency ablation (RFA) is a treatment that ... of Liver Tumors? What is Radiofrequency Ablation of Liver Tumors? Radiofrequency ablation, sometimes referred to as RFA, ...

  18. Extreme-UV electrical discharge source

    DOEpatents

    Fornaciari, Neal R.; Nygren, Richard E.; Ulrickson, Michael A.

    2002-01-01

    An extreme ultraviolet and soft x-ray radiation electric capillary discharge source that includes a boron nitride housing defining a capillary bore that is positioned between two electrodes one of which is connected to a source of electric potential can generate a high EUV and soft x-ray radiation flux from the capillary bore outlet with minimal debris. The electrode that is positioned adjacent the capillary bore outlet is typically grounded. Pyrolytic boron nitride, highly oriented pyrolytic boron nitride, and cubic boron nitride are particularly suited. The boron nitride capillary bore can be configured as an insert that is encased in an exterior housing that is constructed of a thermally conductive material. Positioning the ground electrode sufficiently close to the capillary bore outlet also reduces bore erosion.

  19. Ablative skin resurfacing.

    PubMed

    Chwalek, Jennifer; Goldberg, David J

    2011-01-01

    Ablative skin resurfacing has remained the gold standard for treating photodamage and acne scars since the development of the first CO(2) lasers. CO(2) and Er:YAG lasers emit infrared light, which targets water resulting in tissue contraction and collagen formation. The first ablative laser systems created significant thermal damage resulting in unacceptably high rates of scarring and prolonged healing. Newer devices, such as high-energy pulsed lasers and fractional ablative lasers, are capable of achieving significant improvements with fewer side effects and shorter recovery times. While ablative resurfacing has become safer, careful patient selection is still important to avoid post-treatment scarring, dyspigmentation, and infections. Clinicians utilizing ablative devices need to be aware of possible side effects in order to maximize results and patient satisfaction. This chapter reviews the background of ablative lasers including the types of ablative lasers, mechanism of action, indications for ablative resurfacing, and possible side effects.

  20. Lung surgery - discharge

    MedlinePlus

    Thoracotomy - discharge; Lung tissue removal - discharge; Pneumonectomy - discharge; Lobectomy - discharge; Lung biopsy - discharge; Thoracoscopy - discharge; Video-assisted thoracoscopic surgery - discharge; VATS - ...

  1. Multiple capillary biochemical analyzer

    DOEpatents

    Dovichi, Norman J.; Zhang, Jian Z.

    1995-01-01

    A multiple capillary analyzer allows detection of light from multiple capillaries with a reduced number of interfaces through which light must pass in detecting light emitted from a sample being analyzed, using a modified sheath flow cuvette. A linear or rectangular array of capillaries is introduced into a rectangular flow chamber. Sheath fluid draws individual sample streams through the cuvette. The capillaries are closely and evenly spaced and held by a transparent retainer in a fixed position in relation to an optical detection system. Collimated sample excitation radiation is applied simultaneously across the ends of the capillaries in the retainer. Light emitted from the excited sample is detected by the optical detection system. The retainer is provided by a transparent chamber having inward slanting end walls. The capillaries are wedged into the chamber. One sideways dimension of the chamber is equal to the diameter of the capillaries and one end to end dimension varies from, at the top of the chamber, slightly greater than the sum of the diameters of the capillaries to, at the bottom of the chamber, slightly smaller than the sum of the diameters of the capillaries. The optical system utilizes optic fibres to deliver light to individual photodetectors, one for each capillary tube. A filter or wavelength division demultiplexer may be used for isolating fluorescence at particular bands.

  2. Multiple capillary biochemical analyzer

    DOEpatents

    Dovichi, N.J.; Zhang, J.Z.

    1995-08-08

    A multiple capillary analyzer allows detection of light from multiple capillaries with a reduced number of interfaces through which light must pass in detecting light emitted from a sample being analyzed, using a modified sheath flow cuvette. A linear or rectangular array of capillaries is introduced into a rectangular flow chamber. Sheath fluid draws individual sample streams through the cuvette. The capillaries are closely and evenly spaced and held by a transparent retainer in a fixed position in relation to an optical detection system. Collimated sample excitation radiation is applied simultaneously across the ends of the capillaries in the retainer. Light emitted from the excited sample is detected by the optical detection system. The retainer is provided by a transparent chamber having inward slanting end walls. The capillaries are wedged into the chamber. One sideways dimension of the chamber is equal to the diameter of the capillaries and one end to end dimension varies from, at the top of the chamber, slightly greater than the sum of the diameters of the capillaries to, at the bottom of the chamber, slightly smaller than the sum of the diameters of the capillaries. The optical system utilizes optic fibers to deliver light to individual photodetectors, one for each capillary tube. A filter or wavelength division demultiplexer may be used for isolating fluorescence at particular bands. 21 figs.

  3. Nonequilibrium Ablation of Phenolic Impregnated Carbon Ablator

    NASA Technical Reports Server (NTRS)

    Milos, Frank S.; Chen, Yih K.; Gokcen, Tahir

    2012-01-01

    In previous work, an equilibrium ablation and thermal response model for Phenolic Impregnated Carbon Ablator was developed. In general, over a wide range of test conditions, model predictions compared well with arcjet data for surface recession, surface temperature, in-depth temperature at multiple thermocouples, and char depth. In this work, additional arcjet tests were conducted at stagnation conditions down to 40 W/sq cm and 1.6 kPa. The new data suggest that nonequilibrium effects become important for ablation predictions at heat flux or pressure below about 80 W/sq cm or 10 kPa, respectively. Modifications to the ablation model to account for nonequilibrium effects are investigated. Predictions of the equilibrium and nonequilibrium models are compared with the arcjet data.

  4. Intranasal lobular capillary haemangioma

    PubMed Central

    Nayak, Dipak Ranjan; Bhandarkar, Ajay M; Shivamurthy, Archana; Joy, Jasmi

    2014-01-01

    Lobular capillary haemangioma (LCH) is a benign proliferation of capillaries with a characteristic lobular architecture on microscopy; it has an affinity for mucous membrane and skin of the head and neck. It is extremely rare in the nasal cavity. We present the case of a 45-year-old man who presented with epistaxis without any predisposing factors, which was diagnosed as lobular capillary haemangioma. PMID:25304675

  5. Radical prostatectomy - discharge

    MedlinePlus

    ... prostatectomy - discharge; Laparoscopic radical prostatectomy - discharge; LRP - discharge; Robotic-assisted laparoscopic prostatectomy - discharge ; RALP - discharge; Pelvic lymphadenectomy - discharge; Prostate cancer - prostatectomy

  6. Pulmonary ablation: a primer.

    PubMed

    Roberton, Benjamin J; Liu, David; Power, Mark; Wan, John M C; Stuart, Sam; Klass, Darren; Yee, John

    2014-05-01

    Percutaneous image-guided thermal ablation is safe and efficacious in achieving local control and improving outcome in the treatment of both early stage non-small-cell lung cancer and pulmonary metastatic disease, in which surgical treatment is precluded by comorbidity, poor cardiorespiratory reserve, or unfavorable disease distribution. Radiofrequency ablation is the most established technology, but new thermal ablation technologies such as microwave ablation and cryoablation may offer some advantages. The use of advanced techniques, such as induced pneumothorax and the popsicle stick technique, or combining thermal ablation with radiotherapy, widens the treatment options available to the multidisciplinary team. The intent of this article is to provide the reader with a practical knowledge base of pulmonary ablation by concentrating on indications, techniques, and follow-up.

  7. Renal Ablation Update

    PubMed Central

    Khiatani, Vishal; Dixon, Robert G.

    2014-01-01

    Thermal ablative technologies have evolved considerably in the recent past and are now an important component of current clinical guidelines for the treatment of small renal masses. Both radiofrequency ablation and cryoablation have intermediate-term oncologic control that rivals surgical options, with favorable complication profiles. Studies comparing cryoablation and radiofrequency ablation show no significant difference in oncologic control or complication profile between the two modalities. Early data from small series with microwave ablation have shown similar promising results. Newer technologies including irreversible electroporation and high-intensity–focused ultrasound have theoretical advantages, but will require further research before becoming a routine part of the ablation armamentarium. The purpose of this review article is to discuss the current ablative technologies available, briefly review their mechanisms of action, discuss technical aspects of each, and provide current data supporting their use. PMID:25049445

  8. Radiofrequency Ablation of Cancer

    SciTech Connect

    Friedman, Marc; Mikityansky, Igor; Kam, Anthony; Libutti, Steven K.; Walther, McClellan M.; Neeman, Ziv; Locklin, Julia K.; Wood, Bradford J.

    2004-09-15

    Radiofrequency ablation (RFA) has been used for over 18 years for treatment of nerve-related chronic pain and cardiac arrhythmias. In the last 10 years, technical developments have increased ablation volumes in a controllable, versatile, and relatively inexpensive manner. The host of clinical applications for RFA have similarly expanded. Current RFA equipment, techniques, applications, results, complications, and research avenues for local tumor ablation are summarized.

  9. Lung Ablation: Whats New?

    PubMed

    Xiong, Lillian; Dupuy, Damian E

    2016-07-01

    Lung cancer had an estimated incidence of 221,200 in 2015, making up 13% of all cancer diagnoses. Tumor ablation is an important treatment option for nonsurgical lung cancer and pulmonary metastatic patients. Radiofrequency ablation has been used for over a decade with newer modalities, microwave ablation, cryoablation, and irreversible electroporation presenting as additional and possibly improved treatment options for patients. This minimally invasive therapy is best for small primary lesions or favorably located metastatic tumors. These technologies can offer palliation and sometimes cure of thoracic malignancies. This article discusses the current available technologies and techniques available for tumor ablation.

  10. Ablative Thermal Protection System Fundamentals

    NASA Technical Reports Server (NTRS)

    Beck, Robin A. S.

    2013-01-01

    This is the presentation for a short course on the fundamentals of ablative thermal protection systems. It covers the definition of ablation, description of ablative materials, how they work, how to analyze them and how to model them.

  11. Capillary rheometry for thermosets

    NASA Technical Reports Server (NTRS)

    Malguarnera, S. C.; Carroll, D. R.

    1982-01-01

    Capillary rheometry is effectively used with thermosets. Most important is providing a uniform temperature in the barrel. This was successfully accomplished by using a circulating hot oil system. Standard capillary rheometry methods provide the dependence of thermoset apparent viscosity on shear rate, temperature and time. Such information is very useful in evaluating resin processability and in setting preliminary fabrication conditions.

  12. Vaginal Discharge

    MedlinePlus

    ... also be on the lookout for symptoms of yeast infections, bacterial vaginosis and trichomoniasis, 3 infections that ... cause changes in your vaginal discharge.Signs of yeast infectionsWhite, cottage cheese-like dischargeSwelling and pain around ...

  13. Sprayable lightweight ablative coating

    NASA Technical Reports Server (NTRS)

    Simpson, William G. (Inventor); Sharpe, Max H. (Inventor); Hill, William E. (Inventor)

    1991-01-01

    An improved lightweight, ablative coating is disclosed that may be spray applied and cured without the development of appreciable shrinkage cracks. The ablative mixture consists essentially of phenolic microballoons, hollow glass spheres, glass fibers, ground cork, a flexibilized resin binder, and an activated colloidal clay.

  14. Multiplexed capillary electrophoresis system

    DOEpatents

    Yeung, E.S.; Li, Q.; Lu, X.

    1998-04-21

    The invention provides a side-entry optical excitation geometry for use in a multiplexed capillary electrophoresis system. A charge-injection device is optically coupled to capillaries in the array such that the interior of a capillary is imaged onto only one pixel. In Sanger-type 4-label DNA sequencing reactions, nucleotide identification (``base calling``) is improved by using two long-pass filters to split fluorescence emission into two emission channels. A binary poly(ethyleneoxide) matrix is used in the electrophoretic separations. 19 figs.

  15. Multiplexed capillary electrophoresis system

    DOEpatents

    Yeung, E.S.; Chang, H.T.; Fung, E.N.; Li, Q.; Lu, X.

    1996-12-10

    The invention provides a side-entry optical excitation geometry for use in a multiplexed capillary electrophoresis system. A charge-injection device is optically coupled to capillaries in the array such that the interior of a capillary is imaged onto only one pixel. In Sanger-type 4-label DNA sequencing reactions, nucleotide identification (``base calling``) is improved by using two long-pass filters to split fluorescence emission into two emission channels. A binary poly(ethyleneoxide) matrix is used in the electrophoretic separations. 19 figs.

  16. Multiplexed capillary electrophoresis system

    DOEpatents

    Yeung, Edward S.; Li, Qingbo; Lu, Xiandan

    1998-04-21

    The invention provides a side-entry optical excitation geometry for use in a multiplexed capillary electrophoresis system. A charge-injection device is optically coupled to capillaries in the array such that the interior of a capillary is imaged onto only one pixel. In Sanger-type 4-label DNA sequencing reactions, nucleotide identification ("base calling") is improved by using two long-pass filters to split fluorescence emission into two emission channels. A binary poly(ethyleneoxide) matrix is used in the electrophoretic separations.

  17. Multiplexed capillary electrophoresis system

    DOEpatents

    Yeung, Edward S.; Chang, Huan-Tsang; Fung, Eliza N.; Li, Qingbo; Lu, Xiandan

    1996-12-10

    The invention provides a side-entry optical excitation geometry for use in a multiplexed capillary electrophoresis system. A charge-injection device is optically coupled to capillaries in the array such that the interior of a capillary is imaged onto only one pixel. In Sanger-type 4-label DNA sequencing reactions, nucleotide identification ("base calling") is improved by using two long-pass filters to split fluorescence emission into two emission channels. A binary poly(ethyleneoxide) matrix is used in the electrophoretic separations.

  18. Anti-reflux surgery - discharge

    MedlinePlus

    ... fundoplication - discharge; Toupet fundoplication - discharge; Thal fundoplication - discharge; Hiatal hernia repair - discharge; Endoluminal fundoplication - discharge; GERD - fundoplication discharge; ...

  19. EUS-Guided Ethanol Ablation of Insulinomas

    PubMed Central

    Qin, Shan-yu; Lu, Xiu-ping; Jiang, Hai-xing

    2014-01-01

    Abstract Surgical resection is a standard treatment for insulinomas; however, it is associated with a high risk of complications and limited to specific suitable candidates. In recent years, endoscopic ultrasound (EUS)-guided ethanol ablation of insulinomas has emerged as a new therapeutic option, especially for elderly patients and candidates unfit for surgery. We aimed to evaluate the feasibility and safety of this technique for insulinomas. Four patients diagnosed with insulinomas based on EUS–fine-needle aspiration and immunohistochemistry results underwent EUS-guided 95% ethanol ablation. A comprehensive literature review was performed to understand the current status of the feasibility, safety, and effects of EUS-guided ethanol ablation of insulinomas. EUS-guided ethanol ablation of insulinomas was successfully completed in all the 4 patients. There were no perioperative or postoperative complications. The patients were discharged at 3 days after the procedure. No recurrence of hypoglycemia or tumors was noted during follow-up (range, 3–6 months). Literature review showed 8 patients with insulinomas who underwent EUS-guided ethanol ablation. All the procedures were successful, with no need for further surgical treatment. Among these reviewed cases, 6 patients had no post-procedural complications, while other 2 patients showed a mild increase in the serum levels of lipase and/or pancreatic enzymes within 48 h post-procedure; furthermore, 1 of these 2 patients presented at a later date with medically controllable hematoma and ulceration. During follow-up, 6 patients remained asymptomatic and normoglycemic, while the 2 patients who presented post-procedural complications developed occasional mild confusion. EUS-guided ethanol ablation of insulinomas is an effective and safe modality, with an acceptable level of post-procedural complications. However, the long-term effects of this new therapeutic option need to be validated in a large randomized controlled

  20. Bone marrow transplant - discharge

    MedlinePlus

    Transplant - bone marrow - discharge; Stem cell transplant - discharge; Hematopoietic stem cell transplant - discharge; Reduced intensity; Non-myeloablative transplant - discharge; Mini transplant - discharge; Allogenic bone marrow transplant - ...

  1. Tumor Ablation and Nanotechnology

    PubMed Central

    Manthe, Rachel L.; Foy, Susan P.; Krishnamurthy, Nishanth; Sharma, Blanka; Labhasetwar, Vinod

    2010-01-01

    Next to surgical resection, tumor ablation is a commonly used intervention in the treatment of solid tumors. Tumor ablation methods include thermal therapies, photodynamic therapy, and reactive oxygen species (ROS) producing agents. Thermal therapies induce tumor cell death via thermal energy and include radiofrequency, microwave, high intensity focused ultrasound, and cryoablation. Photodynamic therapy and ROS producing agents cause increased oxidative stress in tumor cells leading to apoptosis. While these therapies are safe and viable alternatives when resection of malignancies is not feasible, they do have associated limitations that prevent their widespread use in clinical applications. To improve the efficacy of these treatments, nanoparticles are being studied in combination with nonsurgical ablation regimens. In addition to better thermal effect on tumor ablation, nanoparticles can deliver anticancer therapeutics that show synergistic anti-tumor effect in the presence of heat and can also be imaged to achieve precision in therapy. Understanding the molecular mechanism of nanoparticle-mediated tumor ablation could further help engineer nanoparticles of appropriate composition and properties to synergize the ablation effect. This review aims to explore the various types of nonsurgical tumor ablation methods currently used in cancer treatment and potential improvements by nanotechnology applications. PMID:20866097

  2. Capillary nail refill test

    MedlinePlus

    ... may indicate: Dehydration Shock Peripheral vascular disease (PVD) Hypothermia Alternative Names Nail blanch test; Capillary refill time ... Elsevier Saunders; 2016:chap 79. Read More Dehydration Hypothermia Peripheral artery disease - legs Shock Review Date 4/ ...

  3. Displaced capillary dies

    DOEpatents

    Kalejs, Juris P.; Chalmers, Bruce; Surek, Thomas

    1984-01-01

    An asymmetrical shaped capillary die made exclusively of graphite is used to grow silicon ribbon which is capable of being made into solar cells that are more efficient than cells produced from ribbon made using a symmetrically shaped die.

  4. Displaced capillary dies

    DOEpatents

    Kalejs, Juris P.; Chalmers, Bruce; Surek, Thomas

    1982-01-01

    An asymmetrical shaped capillary die made exclusively of graphite is used to grow silicon ribbon which is capable of being made into solar cells that are more efficient than cells produced from ribbon made using a symmetrically shaped die.

  5. Capillary rise of superspreaders.

    PubMed

    Radulovic, Jovana; Sefiane, Khellil; Shanahan, Martin E R

    2011-09-15

    Trisiloxane surfactants, known as 'superspreaders', are commonly employed in numerous applications where enhanced wetting is of the utmost importance. The underlying mechanisms of superspreader wetting have been a focus of scientific interest for ca. 2 decades, and a number of mechanisms have been proposed to explain the unique trisiloxane dynamics. We have studied trisiloxane behaviour in thin capillaries to get further insight into their interfacial activity. Additionally, our knowledge of the capillary rise of superspreaders is surprisingly limited, and the effect of this extraordinary group of surfactants on capillary phenomena has been largely overlooked. Diffusion was confirmed to be the limiting factor of trisiloxane behaviour. A tentative theoretical explanation for the phenomenon studied and an appropriate mathematical model are presented. It is concluded that the enhancement of wetting due to surfactant addition is also a function of geometry: the effect is clear for a sessile drop, but more complex and less beneficial in a capillary.

  6. Capillary saturation and desaturation.

    PubMed

    Hilfer, R; Armstrong, R T; Berg, S; Georgiadis, A; Ott, H

    2015-12-01

    Capillary desaturation experiments produce disconnected (trapped) ganglia of mesoscopic sizes intermediate between pore size and system size. Experimental evidence for interactions between these mesoscale clusters during desaturation is analyzed and discussed within the established microscopic and macroscopic laws of Newton, Young-Laplace, and Darcy. A theoretical expression for capillary number correlations is introduced that seems to have remained unnoticed. It expresses capillary desaturation curves in terms of stationary capillary pressures and relative permeabilities. The theoretical expression shows that the plateau saturation in capillary desaturation curves may in general differ from the residual nonwetting saturation defined through the saturation limit of the main hysteresis loop. Hysteresis effects as well as the difference between wetting and nonwetting fluids are introduced into the analysis of capillary desaturation experiments. The article examines experiments with different desaturation protocols and discusses the existence of a mesoscopic length scale intermediate between pore scale and sample scale. The theoretical expression is derived entirely within the existing traditional theory of two-phase flow in porous media and compared to a recent experiment.

  7. Capillary saturation and desaturation

    NASA Astrophysics Data System (ADS)

    Hilfer, R.; Armstrong, R. T.; Berg, S.; Georgiadis, A.; Ott, H.

    2015-12-01

    Capillary desaturation experiments produce disconnected (trapped) ganglia of mesoscopic sizes intermediate between pore size and system size. Experimental evidence for interactions between these mesoscale clusters during desaturation is analyzed and discussed within the established microscopic and macroscopic laws of Newton, Young-Laplace, and Darcy. A theoretical expression for capillary number correlations is introduced that seems to have remained unnoticed. It expresses capillary desaturation curves in terms of stationary capillary pressures and relative permeabilities. The theoretical expression shows that the plateau saturation in capillary desaturation curves may in general differ from the residual nonwetting saturation defined through the saturation limit of the main hysteresis loop. Hysteresis effects as well as the difference between wetting and nonwetting fluids are introduced into the analysis of capillary desaturation experiments. The article examines experiments with different desaturation protocols and discusses the existence of a mesoscopic length scale intermediate between pore scale and sample scale. The theoretical expression is derived entirely within the existing traditional theory of two-phase flow in porous media and compared to a recent experiment.

  8. Thermal ablation for hepatocellular carcinoma.

    PubMed

    Head, Hayden W; Dodd, Gerald D

    2004-11-01

    Thermal ablation, as a form of minimally invasive therapy for hepatocellular carcinoma (HCC), has become an important treatment modality. Because of the limitations of surgery, the techniques of thermal ablation have become standard therapies for HCC in some situations. This article reviews 4 thermal ablation techniques-radiofrequency (RF) ablation, microwave ablation, laser ablation, and cryoablation. Each of these techniques may have a role in treating HCC, and the mechanisms, equipment, patient selection, results, and complications of each are considered. Furthermore, combined therapies consisting of thermal ablation and adjuvant chemotherapy also show promise for enhancing these techniques. Important areas of research into thermal ablation remain, including improving the ability of ablation to treat larger tumors, determining the indications for each thermal ablation modality, optimizing image guidance, and obtaining good outcome data on the efficacy of these techniques.

  9. Ablative skin resurfacing.

    PubMed

    Agrawal, Nidhi; Smith, Greg; Heffelfinger, Ryan

    2014-02-01

    Ablative laser resurfacing has evolved as a safe and effective treatment for skin rejuvenation. Although traditional lasers were associated with significant thermal damage and lengthy recovery, advances in laser technology have improved safety profiles and reduced social downtime. CO2 lasers remain the gold standard of treatment, and fractional ablative devices capable of achieving remarkable clinical improvement with fewer side effects and shorter recovery times have made it a more practical option for patients. Although ablative resurfacing has become safer, careful patient selection and choice of suitable laser parameters are essential to minimize complications and optimize outcomes. This article describes the current modalities used in ablative laser skin resurfacing and examines their efficacy, indications, and possible side effects.

  10. Moldable cork ablation material

    NASA Technical Reports Server (NTRS)

    1977-01-01

    A successful thermal ablative material was manufactured. Moldable cork sheets were tested for density, tensile strength, tensile elongation, thermal conductivity, compression set, and specific heat. A moldable cork sheet, therefore, was established as a realistic product.

  11. Role of shielding in modelling cryogenic deuterium pellet ablation

    NASA Astrophysics Data System (ADS)

    Gál, K.; Belonohy, É.; Kocsis, G.; Lang, P. T.; Veres, G.; ASDEX Upgrade Team

    2008-08-01

    For the better characterization of pellet ablation, the numerical LLP code has been enhanced by combining two relevant shielding mechanisms: that of the spherically expanding neutral cloud surrounding the pellet and that of the field elongated ionized material forming a channel flow. In contrast to our expectation the presence of the channel flow can increase the ablation rate although it reduces the heat flux travelling through it. The contribution of the different shielding effect in the ablation process is analysed for several pellet and plasma parameters and an ablation rate scaling is presented based on simple regression in the ASDEX Upgrade pellet and plasma parameter range. Finally the simulated results are compared with experimental data from typical ASDEX Upgrade discharges.

  12. Endometrial Ablation for Menorrhagia

    PubMed Central

    Sanders, Barry H.

    1992-01-01

    Endometrial ablation is a relatively new treatment for patients with persistent menorrhagia. The procedure can be performed by either laser photocoagulation or electrocoagulation; both have a very low risk of complication. Generally, less than 24 hours of hospitalization is required and return to normal activities, including work, is almost immediate. Endometrial ablation is likely to become a mainstay of treatment for menorrhagia as the technology and training become more readily available. PMID:21229128

  13. Ignition relevant ablator response of boron carbide and high-density carbon driven by multiple shocks

    NASA Astrophysics Data System (ADS)

    Prisbrey, Shon T.; Baker, Kevin; Celliers, Peter; Dittrich, Tom; Moore, Alastair; Wu, Kuang Jen; Kervin, Peggy; Hurricane, Omar

    2013-10-01

    The attainment of self-propagating fusion burn in an inertial confinement target at the National Ignition Facility will require the use of an ablator with high rocket-efficiency and ablation pressure. The current ablation material, a glow-discharge polymer (GDP), does not couple as efficiently as simulations indicated to the multiple-shock inducing radiation drive environment created by laser power profile. In an effort to evaluate the performance of other possible ablators that could be suitable for achieving self-propagating fusion burn we have inferred the ablation performance of two possible ablators, boron carbide and high-density carbon, by measuring the shock speed of induced shocks while subjecting the ablators to a multiple-shock inducing radiation drive environment similar to a generic three-shock ignition drive. We present the platform used, velocity measurements used to infer the ablation response, and matching simulations to show the relative performance of boron carbide and high-density carbon with a general comparison to current performance of the currently used glow-discharge polymer ablator. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344. Lawrence Livermore National Security, LLC. LLNL-ABS-640519.

  14. Derivatization in Capillary Electrophoresis.

    PubMed

    Marina, M Luisa; Castro-Puyana, María

    2016-01-01

    Capillary electrophoresis is a well-established separation technique in analytical research laboratories worldwide. Its interesting advantages make CE an efficient and potent alternative to other chromatographic techniques. However, it is also recognized that its main drawback is the relatively poor sensitivity when using optical detection. One way to overcome this limitation is to perform a derivatization reaction which is intended to provide the analyte more suitable analytical characteristics enabling a high sensitive detection. Based on the analytical step where the CE derivatization takes place, it can be classified as precapillary (before separation), in-capillary (during separation), or postcapillary (after separation). This chapter describes the application of four different derivatization protocols (in-capillary and precapillary modes) to carry out the achiral and chiral analysis of different compounds in food and biological samples with three different detection modes (UV, LIF, and MS).

  15. Capillary condenser/evaporator

    NASA Technical Reports Server (NTRS)

    Valenzuela, Javier A. (Inventor)

    2010-01-01

    A heat transfer device is disclosed for transferring heat to or from a fluid that is undergoing a phase change. The heat transfer device includes a liquid-vapor manifold in fluid communication with a capillary structure thermally connected to a heat transfer interface, all of which are disposed in a housing to contain the vapor. The liquid-vapor manifold transports liquid in a first direction and conducts vapor in a second, opposite direction. The manifold provides a distributed supply of fluid (vapor or liquid) over the surface of the capillary structure. In one embodiment, the manifold has a fractal structure including one or more layers, each layer having one or more conduits for transporting liquid and one or more openings for conducting vapor. Adjacent layers have an increasing number of openings with decreasing area, and an increasing number of conduits with decreasing cross-sectional area, moving in a direction toward the capillary structure.

  16. Septoplasty - discharge

    MedlinePlus

    ... this page: //medlineplus.gov/ency/patientinstructions/000246.htm Septoplasty - discharge To use the sharing features on this page, please enable JavaScript. Septoplasty is surgery to correct any problems in the ...

  17. Osteomyelitis - discharge

    MedlinePlus

    ... this page: //medlineplus.gov/ency/patientinstructions/000297.htm Osteomyelitis - discharge To use the sharing features on this page, please enable JavaScript. You have osteomyelitis , a bone infection caused by bacteria or other ...

  18. Cirrhosis - discharge

    MedlinePlus

    ... this page: //medlineplus.gov/ency/patientinstructions/000290.htm Cirrhosis - discharge To use the sharing features on this page, please enable JavaScript. You have cirrhosis of the liver. Scar tissue forms and your ...

  19. Infrared laser bone ablation

    SciTech Connect

    Nuss, R.C.; Fabian, R.L.; Sarkar, R.; Puliafito, C.A.

    1988-01-01

    The bone ablation characteristics of five infrared lasers, including three pulsed lasers (Nd:YAG, lambda = 1064 micron; Hol:YSGG, lambda = 2.10 micron; and Erb:YAG, lambda = 2.94 micron) and two continuous-wave lasers (Nd:YAG, lambda = 1.064 micron; and CO/sub 2/, lambda = 10.6 micron), were studied. All laser ablations were performed in vitro, using moist, freshly dissected calvarium of guinea pig skulls. Quantitative etch rates of the three pulsed lasers were calculated. Light microscopy of histologic sections of ablated bone revealed a zone of tissue damage of 10 to 15 micron adjacent to the lesion edge in the case of the pulsed Nd:YAG and the Erb:YAG lasers, from 20 to 90 micron zone of tissue damage for bone ablated by the Hol:YSGG laser, and 60 to 135 micron zone of tissue damage in the case of the two continuous-wave lasers. Possible mechanisms of bone ablation and tissue damage are discussed.

  20. Cardiac catheterization - discharge

    MedlinePlus

    Catheterization - cardiac - discharge; Heart catheterization - discharge: Catheterization - cardiac; Heart catheterization; Angina - cardiac catheterization discharge; CAD - cardiac catheterization discharge; Coronary artery disease - cardiac catheterization ...

  1. Newborn jaundice - discharge

    MedlinePlus

    ... Jaundice of the newborn - discharge; Neonatal hyperbilirubinemia - discharge; Breastfeeding jaundice - discharge; Physiologic jaundice - discharge Images Exchange transfusion - series Infant jaundice References Kaplan M, ...

  2. Kidney removal - discharge

    MedlinePlus

    ... nephrectomy - discharge; Open nephrectomy - discharge; Laparoscopic nephrectomy - discharge; Partial nephrectomy - discharge ... Plan to have someone drive you home from the hospital. DO NOT drive yourself home. You may ...

  3. Atrial fibrillation - discharge

    MedlinePlus

    Auricular fibrillation - discharge; A-fib - discharge; AF - discharge; Afib - discharge ... been in the hospital because you have atrial fibrillation . This condition occurs when your heart beats faster ...

  4. Study of breakdown in an ablative pulsed plasma thruster

    SciTech Connect

    Huang, Tiankun; Wu, Zhiwen; Liu, Xiangyang; Xie, Kan; Wang, Ningfei; Cheng, Yue

    2015-10-15

    Breakdown in ablative pulsed plasma thrusters (APPTs) must be studied in order to design new types of APPTs and measure particular parameters. In this paper, we studied a parallel-plate ablative pulsed plasma thruster that used a coaxial semiconductor spark plug. By operating the APPT about 500 times with various capacitor voltages and electrode gaps, we measured and analyzed the voltage of the spark plug, the voltage between the electrodes, and the discharge current. These experiments revealed a time delay (∼1–10 μs) between spark plug ignition and capacitor discharge, which may affect the performance of high-pulsing-rate (>10 kHz) and double-discharge APPTs, and the measurements of some of the APPT parameters. The delay time decreased as the capacitor voltage increased, and it increased with an increasing electrode gap and increasing number of ignitions. We explain our results through a simple theoretical analysis.

  5. Capillary action liquid chromatography.

    PubMed

    Zhang, Bo; Bergström, Edmund T; Goodall, David M; Myers, Peter

    2009-06-01

    Capillary action LC (caLC) is introduced as a technique using capillary action as the driving force to perform LC in capillary columns packed with HPLC type microparticulate materials. A dry packing method with centrifugal force was developed to prepare capillary columns in parallel (10 columns per 3 min) to support their disposable use in caLC. Using a digital microscope for real-time imaging and recording separations of components in a dye mixture, caLC was found to have flow characteristics similar to TLC. Based on the investigation of microparticulate HPLC silica gels of different size (1.5-10 microm) and a typical TLC grade irregular medium, Merck 60G silica, the van Deemter curves suggested molecular diffusion as the major contribution to band broadening in caLC. With Waters Xbridge 2.6 microm silica, plate heights down to 8.8 microm were obtained, comparable to those achievable in HPLC. Assisted by an image-processing method, the visual caLC separation was converted to a classical chromatogram for further data analysis and such a facility confirmed the observation of highly efficient bands.

  6. Shuttle subscale ablative nozzle tests

    NASA Technical Reports Server (NTRS)

    Powers, L. B.; Bailey, R. L.

    1980-01-01

    Recent subscale nozzle tests have identified new and promising carbon phenolic nozzle ablatives which utilize staple rayon, PAN, and pitch based carbon cloth. A 4-inch throat diameter submerged test nozzle designed for the 48-inch Jet Propulsion Laboratory char motor was used to evaluate five different designs incorporating 20 candidate ablatives. Test results indicate that several pitch and PAN-based carbon phenolic ablatives can provide erosion and char performance equivalent or superior to the present continuous rayon-based SRM ablative.

  7. Noise suppressing capillary separation system

    DOEpatents

    Yeung, Edward S.; Xue, Yongjun

    1996-07-30

    A noise-suppressing capillary separation system for detecting the real-time presence or concentration of an analyte in a sample is provided. The system contains a capillary separation means through which the analyte is moved, a coherent light source that generates a beam which is split into a reference beam and a sample beam that irradiate the capillary, and a detector for detecting the reference beam and the sample beam light that transmits through the capillary. The laser beam is of a wavelength effective to be absorbed by a chromophore in the capillary. The system includes a noise suppressing system to improve performance and accuracy without signal averaging or multiple scans.

  8. Nipple Discharge

    MedlinePlus

    ... If the ultrasound shows a lesion within a milk duct, you may need a biopsy to confirm that it's a papilloma or to exclude a cancer. Nipple discharge is rarely a sign of breast cancer. But it might be a sign of ...

  9. Percutaneous ablation of adrenal tumors.

    PubMed

    Venkatesan, Aradhana M; Locklin, Julia; Dupuy, Damian E; Wood, Bradford J

    2010-06-01

    Adrenal tumors comprise a broad spectrum of benign and malignant neoplasms and include functional adrenal adenomas, pheochromocytomas, primary adrenocortical carcinoma, and adrenal metastases. Percutaneous ablative approaches that have been described and used in the treatment of adrenal tumors include percutaneous radiofrequency ablation, cryoablation, microwave ablation, and chemical ablation. Local tumor ablation in the adrenal gland presents unique challenges, secondary to the adrenal gland's unique anatomic and physiological features. The results of clinical series employing percutaneous ablative techniques in the treatment of adrenal tumors are reviewed in this article. Clinical and technical considerations unique to ablation in the adrenal gland are presented, including approaches commonly used in our practices, and risks and potential complications are discussed.

  10. Capillary Isoelectric Focusing

    NASA Astrophysics Data System (ADS)

    Markuszewski, Michał J.; Bujak, Renata; Daghir, Emilia

    Capillary isoelectric focusing (CIEF) is a widespread technique for the analysis of peptides and proteins in biological samples. CIEF is used to separate mixtures of compounds on the basis of differences in their isoelectric point. Aspects of sample preparation, capillary selection, zone mobilization procedures as well as various detection modes used have been described and discussed. Moreover CIEF, coupled to various types of detection techniques (MALDI or LIF), has increasingly been applied to the analysis of variety different high-molecular compounds. CIEF is considered as a highly specific analytical method which may be routinely used in the separation of rare hemoglobin variants. In addition, the application of CIEF in proteomic field have been discussed on the examples of analyses of glycoproteins and immunoglobins due to the meaning in clinical diagnostic.

  11. Enantioseparations by capillary electrochromatography.

    PubMed

    Fanali, S; Catarcini, P; Blaschke, G; Chankvetadze, B

    2001-09-01

    The review summarizes recent developments in enantioseparations by capillary electrochromatography (CEC). Selected fundamental aspects of CEC are discussed in order to stress those features which may allow the success of this technique in the competitive field of enantioseparations. In addition, the comparative characteristics of the different modes of chiral CEC and the stationary phases are presented. The effects of the characteristics of the stationary and liquid phases and operational conditions on the separation results are discussed. Finally, some future trends are briefly addressed.

  12. Ablation of skeletal metastases: current status.

    PubMed

    Kurup, A Nicholas; Callstrom, Matthew R

    2010-08-01

    Image-guided percutaneous ablation of bone metastases is an effective, minimally invasive alternative to conventional therapies in the palliation of pain from metastatic disease. Ablative technologies applied in the treatment of skeletal metastases include radiofrequency ablation, cryoablation, microwave ablation, laser ablation, ethanol ablation, and, most recently, focused ultrasound. These ablative methods may be performed in combination with percutaneous cementoplasty to provide support and stabilization for metastases in weight-bearing bones at risk for pathologic fracture.

  13. Automated Parallel Capillary Electrophoretic System

    DOEpatents

    Li, Qingbo; Kane, Thomas E.; Liu, Changsheng; Sonnenschein, Bernard; Sharer, Michael V.; Kernan, John R.

    2000-02-22

    An automated electrophoretic system is disclosed. The system employs a capillary cartridge having a plurality of capillary tubes. The cartridge has a first array of capillary ends projecting from one side of a plate. The first array of capillary ends are spaced apart in substantially the same manner as the wells of a microtitre tray of standard size. This allows one to simultaneously perform capillary electrophoresis on samples present in each of the wells of the tray. The system includes a stacked, dual carousel arrangement to eliminate cross-contamination resulting from reuse of the same buffer tray on consecutive executions from electrophoresis. The system also has a gel delivery module containing a gel syringe/a stepper motor or a high pressure chamber with a pump to quickly and uniformly deliver gel through the capillary tubes. The system further includes a multi-wavelength beam generator to generate a laser beam which produces a beam with a wide range of wavelengths. An off-line capillary reconditioner thoroughly cleans a capillary cartridge to enable simultaneous execution of electrophoresis with another capillary cartridge. The streamlined nature of the off-line capillary reconditioner offers the advantage of increased system throughput with a minimal increase in system cost.

  14. Infrared Laser Ablation Sample Transfer for MALDI and Electrospray

    NASA Astrophysics Data System (ADS)

    Park, Sung-Gun; Murray, Kermit King

    2011-08-01

    We have used an infrared laser to ablate materials under ambient conditions that were captured in solvent droplets. The droplets were either deposited on a MALDI target for off-line analysis by MALDI time-of-flight mass spectrometry or flow-injected into a nanoelectrospray source of an ion trap mass spectrometer. An infrared optical parametric oscillator (OPO) laser system at 2.94 μm wavelength and approximately 1 mJ pulse energy was focused onto samples for ablation at atmospheric pressure. The ablated material was captured in a solvent droplet 1-2 mm in diameter that was suspended from a silica capillary a few millimeters above the sample target. Once the sample was transferred to the droplet by ablation, the droplet was deposited on a MALDI target. A saturated matrix solution was added to the deposited sample, or in some cases, the suspended capture droplet contained the matrix. Peptide and protein standards were used to assess the effects of the number of IR laser ablation shots, sample to droplet distance, capture droplet size, droplet solvent, and laser pulse energy. Droplet collected samples were also injected into a nanoelectrospray source of an ion trap mass spectrometer with a 500 nL injection loop. It is estimated that pmol quantities of material were transferred to the droplet with an efficiency of approximately 1%. The direct analysis of biological fluids for off-line MALDI and electrospray was demonstrated with blood, milk, and egg. The implications of this IR ablation sample transfer approach for ambient imaging are discussed.

  15. Capillary Discharge Thruster Experiments and Modeling (Briefing Charts)

    DTIC Science & Technology

    2016-06-01

    Martin1 ERC INC.1, IN-SPACE PROPULSION BRANCH, AIR FORCE RESEARCH LABORATORY EDWARDS AIR FORCE BASE, CA USA Electric propulsion systems June 2016... Propulsion Plumes FRC Chamber Environment R.S. MARTIN (ERC INC.) DISTRIBUTION A: APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED; PA# 16279 3 / 30 ELECTRIC ...FUTURE WORK 5 CONCLUSION R.S. MARTIN (ERC INC.) DISTRIBUTION A: APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED; PA# 16279 2 / 30 ELECTRIC

  16. Rapid fabrication of supercapacitor electrodes using bionanoscaffolds in capillary microfluidics

    NASA Astrophysics Data System (ADS)

    Zang, F.; Chu, S.; Gerasopoulos, K.; Culver, J. N.; Ghodssi, R.

    2015-12-01

    This paper reports the utilization of capillary microfluidics to rapidly create nanostructure-patterned electrodes for energy storage applications. Using patterned photoresist as open-channel capillary microfluidics, Tobacco mosaic virus (TMV) bio-nanoscaffolds suspended in solution are autonomously delivered onto planar gold electrodes over a 1 cm2 area. The TMVs assemble on the electrode and form a dense bio-nanoscaffold layer due to enhanced evaporation-assisted assembly in the open-channel capillary microfluidic device within an hour. The TMV structures are coated with Ni/NiO through electroless plating and thermal oxidation to form supercapacitor electrodes. The galvanostatic charge/discharge cycle showed a 3.6-fold increase in areal capacitance for the nanostructured electrode compared to planar structures.

  17. [Ablative and fractional lasers].

    PubMed

    Beylot, C; Grognard, C; Michaud, T

    2009-10-01

    The use of pulsed or scanning Carbon Dioxide, and pulsed Erbium-YAG lasers allows the programmable and reproducible photocoagulation of thin layers of the epidermis and superficial dermis. Thermal damage depends on the type of laser and is greater with CO(2) lasers. The degree of neocollagenesis is proportional to the thermal damage and is better with CO(2) lasers. Their main indication is the correction of photoaged facial skin but they can also be used for corrective dermatology, e.g. for scars and genodermatosis. Results are highly satisfactory but the technique is invasive and the patient experiences a social hindrance of around two weeks. Fractionated techniques treat 25% of the defective skin area at each session in noncontiguous microzones; four sessions are therefore necessary to treat the entire cutaneous surface. The treatment is given under topical anesthesia and is much less invasive, particularly with nonablative fractional laser treatment in which photothermolysis does not penetrate below the epidermis and/or the effects are slight, with no or very little social isolation. However, the results are much less satisfactory than the results of ablative laser and there is no firming effect. Other zones than the face can be treated. With the fractional CO(2) and Erbium ablative lasers, which have multiplied over the past 2 years, the much wider impacts cause perforation of the epidermis and there is a zone of ablation by laser photovaporization, with a zone of thermal damage below. The results are better in correcting photoaging of the face, without, however, achieving the efficacy of ablative lasers, which remain the reference technique. However, the effects are not insignificant, requiring at least 5 days of social isolation.

  18. Capillary reference half-cell

    DOEpatents

    Hall, Stephen H.

    1996-01-01

    The present invention is a reference half-cell electrode wherein intermingling of test fluid with reference fluid does not affect the performance of the reference half-cell over a long time. This intermingling reference half-cell may be used as a single or double junction submersible or surface reference electrode. The intermingling reference half-cell relies on a capillary tube having a first end open to reference fluid and a second end open to test fluid wherein the small diameter of the capillary tube limits free motion of fluid within the capillary to diffusion. The electrode is placed near the first end of the capillary in contact with the reference fluid. The method of operation of the present invention begins with filling the capillary tube with a reference solution. After closing the first end of the capillary, the capillary tube may be fully submerged or partially submerged with the second open end inserted into test fluid. Since the electrode is placed near the first end of the capillary, and since the test fluid may intermingle with the reference fluid through the second open end only by diffusion, this intermingling capillary reference half-cell provides a stable voltage potential for long time periods.

  19. Capillary reference half-cell

    DOEpatents

    Hall, S.H.

    1996-02-13

    The present invention is a reference half-cell electrode wherein intermingling of test fluid with reference fluid does not affect the performance of the reference half-cell over a long time. This intermingling reference half-cell may be used as a single or double junction submersible or surface reference electrode. The intermingling reference half-cell relies on a capillary tube having a first end open to reference fluid and a second end open to test fluid wherein the small diameter of the capillary tube limits free motion of fluid within the capillary to diffusion. The electrode is placed near the first end of the capillary in contact with the reference fluid. The method of operation of the present invention begins with filling the capillary tube with a reference solution. After closing the first end of the capillary, the capillary tube may be fully submerged or partially submerged with the second open end inserted into test fluid. Since the electrode is placed near the first end of the capillary, and since the test fluid may intermingle with the reference fluid through the second open end only by diffusion, this intermingling capillary reference half-cell provides a stable voltage potential for long time periods. 11 figs.

  20. Repetitive XUV Discharge-Pumped Laser at 46.9 nm

    NASA Astrophysics Data System (ADS)

    Schmidt, Jiri; Kolacek, Karel; Frolov, Oleksandr; Prukner, Vaclav; Straus, Jaroslav

    For testing and application purposes we built a new small Marx generator capable to run in a repetitive regime. Its repeating frequency is currently up to 1 Hz. The generator is covered by metal sheets and feeds the capillary discharge device. The first experimental measurements were performed for a 400 mm long capillary and these results are presented.

  1. Transient and Capillary Collisional X-ray Laser

    SciTech Connect

    Shlyaptsev, V N; Dunn, J; Fournier, K B; Moon, S; Osterheld, A L; Rocca, J J; Detering, F; Rozmus, W; Matte, J P; Fiedorowicz, H; Bartnik, A; Kanouff, M

    2001-12-17

    In this work we report our numerical modeling results of laser-generated transient inversion and capillary discharge X-ray lasers. In the search for more efficient X-ray lasers we look closely at other approaches in conjunction with experiments at LLNL. In the search for improved X-ray lasers we perform modeling and experimental investigations of low density targets including gas puff targets. We have found the importance of plasma kinetics in transient X-ray lasers by expanding the physical model beyond hydrodynamics approach with Particle In Cell (PIC) and Fokker-Planck codes. The evidence of the Langdon effect was inferred from the recent experimental data obtained with the Ni-like Pd X-ray laser. We continue modeling different kinds of capillary discharge plasma configurations directed toward shorter wavelength X-ray lasers, plasma diagnostics and other applications.

  2. OCDR guided laser ablation device

    DOEpatents

    Dasilva, Luiz B.; Colston, Jr., Bill W.; James, Dale L.

    2002-01-01

    A guided laser ablation device. The device includes a mulitmode laser ablation fiber that is surrounded by one or more single mode optical fibers that are used to image in the vicinity of the laser ablation area to prevent tissue damage. The laser ablation device is combined with an optical coherence domain reflectometry (OCDR) unit and with a control unit which initializes the OCDR unit and a high power laser of the ablation device. Data from the OCDR unit is analyzed by the control unit and used to control the high power laser. The OCDR images up to about 3 mm ahead of the ablation surface to enable a user to see sensitive tissue such as a nerve or artery before damaging it by the laser.

  3. Catheter Ablation for Ventricular Arrhythmias

    PubMed Central

    Nof, Eyal; Stevenson, William G; John, Roy M

    2013-01-01

    Catheter ablation has emerged as an important and effective treatment option for many recurrent ventricular arrhythmias. The approach to ablation and the risks and outcomes are largely determined by the nature of the severity and type of underlying heart disease. In patients with structural heart disease, catheter ablation can effectively reduce ventricular tachycardia (VT) episodes and implantable cardioverter defibrillator (ICD) shocks. For VT and symptomatic premature ventricular beats that occur in the absence of structural heart disease, catheter ablation is often effective as the sole therapy. Advances in catheter technology, imaging and mapping techniques have improved success rates for ablation. This review discusses current approaches to mapping and ablation for ventricular arrhythmias. PMID:26835040

  4. Hysterectomy - vaginal - discharge

    MedlinePlus

    Vaginal hysterectomy - discharge; Laparoscopically assisted vaginal hysterectomy - discharge; LAVH - discharge ... you were in the hospital, you had a vaginal hysterectomy. Your surgeon made a cut in your ...

  5. Tubal ligation - discharge

    MedlinePlus

    ... discharge; Tube tying - discharge; Tying the tubes - discharge; Contraception - tubal ... chap 23. Jensen JT, Mishell DR. Family planning: contraception, sterilization, and pregnancy termination. In: Lentz GM, Lobo ...

  6. Capillary rogue waves.

    PubMed

    Shats, M; Punzmann, H; Xia, H

    2010-03-12

    We report the first observation of extreme wave events (rogue waves) in parametrically driven capillary waves. Rogue waves are observed above a certain threshold in forcing. Above this threshold, frequency spectra broaden and develop exponential tails. For the first time we present evidence of strong four-wave coupling in nonlinear waves (high tricoherence), which points to modulation instability as the main mechanism in rogue waves. The generation of rogue waves is identified as the onset of a distinct tail in the probability density function of the wave heights. Their probability is higher than expected from the measured wave background.

  7. Mass-controlled capillary viscometer for a Newtonian liquid: viscosity of water at different temperatures.

    PubMed

    Digilov, Rafael M; Reiner, M

    2007-03-01

    The operation principle of the mass-controlled capillary viscometer is presented for a Newtonian liquid. The derived equation for the temporal changes of the mass in a liquid column draining under gravity through a discharge capillary tube accounts self-consistently for the inertial convective term associated with the acceleration effect. The viscosity of water measured at different temperatures using the new approach is in good agreement with literature data.

  8. Means of introducing an analyte into liquid sampling atmospheric pressure glow discharge

    DOEpatents

    Marcus, R. Kenneth; Quarles, Jr., Charles Derrick; Russo, Richard E.; Koppenaal, David W.; Barinaga, Charles J.; Carado, Anthony J.

    2017-01-03

    A liquid sampling, atmospheric pressure, glow discharge (LS-APGD) device as well as systems that incorporate the device and methods for using the device and systems are described. The LS-APGD includes a hollow capillary for delivering an electrolyte solution to a glow discharge space. The device also includes a counter electrode in the form of a second hollow capillary that can deliver the analyte into the glow discharge space. A voltage across the electrolyte solution and the counter electrode creates the microplasma within the glow discharge space that interacts with the analyte to move it to a higher energy state (vaporization, excitation, and/or ionization of the analyte).

  9. Radiofrequency Ablation for Liver Cancer.

    PubMed

    Jacobs, Amy

    2015-01-01

    Interventional ablative technologies aided by imaging techniques such as ultrasonography, computed tomography, and magnetic resonance imaging have been crucial in managing patients with primary liver cancer and liver metastases over the past 20 years. Several ablative technologies have been used to treat liver cancer; however, radiofrequency ablation (RFA) has emerged as the most common ablative therapy for hepatic lesions, both in the United States and globally. RFA is the treatment of choice for patients who cannot have surgical resection of the liver. This article focuses on the role of imaging in RFA treatment of primary and metastatic hepatic lesions.

  10. Capillary suspensions: Particle networks formed through the capillary force

    PubMed Central

    Koos, Erin

    2014-01-01

    The addition of small amounts of a secondary fluid to a suspension can, through the attractive capillary force, lead to particle bridging and network formation. The capillary bridging phenomenon can be used to stabilize particle suspensions and precisely tune their rheological properties. This effect can even occur when the secondary fluid wets the particles less well than the bulk fluid. These materials, so-called capillary suspensions, have been the subject of recent research studying the mechanism for network formation, the properties of these suspensions, and how the material properties can be modified. Recent work in colloidal clusters is summarized and the relationship to capillary suspensions is discussed. Capillary suspensions can also be used as a pathway for new material design and some of these applications are highlighted. Results obtained to date are summarized and central questions that remain to be answered are proposed in this review. PMID:25729316

  11. Tapered capillary optics

    DOEpatents

    Hirsch, Gregory

    1998-01-01

    A metal or glass wire is etched with great precision into a very narrowly tapering cone which has the shape of the desired final capillary-optics bore. By controlling the rate of removal of the wire from an etchant bath, a carefully controlled taper is produced. A sensor measures the diameter of the wire as it leaves the surface of the etchant. This signal is used for feedback control of the withdrawal speed. The etched wire undergoes a treatment to produce an extremely low surface-roughness. The etched and smoothed wire is coated with the material of choice for optimizing the reflectivity of the radiation being focused. This could be a vacuum evaporation, sputtering, CVD or aqueous chemical process. The coated wire is either electroplated, built up with electroless plating, or encapsulated in a polymer cylinder such as epoxy to increase the diameter of the wire for easier handling and greater robustness. During this process, the wire is vertically oriented and tensioned to assure that the wire is absolutely straight. The coated and electroformed wire is bonded to a flat, rigid substrate and is then periodically segmented by cutting or etching a series of narrow slits or grooves into the wire. The wire is vertically oriented and tensioned during the bonding process to assure that it is straight. The original wire material is then chemically etched away through the slits or otherwise withdrawn to leave the hollow internal bore of the final tapered-capillary optical element.

  12. Gastroesophageal reflux - discharge

    MedlinePlus

    Peptic esophagitis - discharge; Reflux esophagitis - discharge; GERD - discharge; Heartburn - chronic - discharge ... You have gastroesophageal reflux disease (GERD). This is a condition in which food or liquid travels backwards from the stomach to the esophagus ( ...

  13. Ventriculoperitoneal shunt - discharge

    MedlinePlus

    ... ventriculoperitoneal - discharge; VP shunt - discharge; Shunt revision - discharge; Hydrocephalus shunt placement - discharge ... Your child has hydrocephalus and needed a shunt placed to drain excess fluid and relieve pressure in the brain. This buildup of brain ...

  14. Refractive corneal surgery - discharge

    MedlinePlus

    Nearsightedness surgery - discharge; Refractive surgery - discharge; LASIK - discharge; PRK - discharge ... You had refractive corneal surgery to help improve your vision. This surgery uses a laser to reshape your cornea. It corrects mild-to-moderate nearsightedness, ...

  15. On Capillary Rise and Nucleation

    ERIC Educational Resources Information Center

    Prasad, R.

    2008-01-01

    A comparison of capillary rise and nucleation is presented. It is shown that both phenomena result from a balance between two competing energy factors: a volume energy and a surface energy. Such a comparison may help to introduce nucleation with a topic familiar to the students, capillary rise. (Contains 1 table and 3 figures.)

  16. Direct chemical-analysis of uv laser-ablation products of organic polymers by using selective ion monitoring mode in gas-chromatography mass-spectrometry

    USGS Publications Warehouse

    Cho, Yirang; Lee, H.W.; Fountain, S.T.; Lubman, D.M.

    1994-01-01

    Trace quantities of laser ablated organic polymers were analyzed by using commercial capillary column gas chromatography/mass spectrometry; the instrument was modified so that the laser ablation products could be introduced into the capillary column directly and the constituents of each peak in the chromatogram were identified by using a mass spectrometer. The present study takes advantage of the selective ion monitoring mode for significantly improving the sensitivity of the mass spectrometer as a detector, which is critical in analyzing the trace quantities and confirming the presence or absence of the species of interest in laser ablated polymers. The initial composition of the laser ablated polymers was obtained by using an electron impact reflectron time-of-flight mass spectrometer and the possible structure of the fragments observed in the spectra was proposed based on the structure of the polymers.

  17. Capillary optics for radiation focusing

    SciTech Connect

    Peurrung, A.J.; Reeder, P.L.; Bliss, M.; Craig, R.A.; Lepel, E.A.; Stromswold, D.C.; Stoffels, J.; Sunberg, D.S.; Tenny, H.

    1996-11-01

    Capillary lens technology may ultimately bring benefits to neutron and x-ray-based science like conventional lenses with visible light. Although the technology is not yet 10 years old, these lenses have already had a significant impact in engineering, science, and medicine. Capillary lenses are advantageous when it is desirable to increase the radiation flux at a location without regard to its angular divergence. PNNL has worked to improve the technology in several ways. A single, optimally tapered capillary was manufactured, which allows intensity gains of a factor of 270 for an initially parallel, incident x-ray beam. Feasibility of constructing neutron lenses using {sup 58}Ni (particularly effective at reflecting neutrons) has been explored. Three applications for capillary optics have been identified and studied: neutron telescope, Gandolphi x-ray diffractometry, and neutron radiotherapy. A brief guide is given for determining which potential applications are likely to be helped by capillary optics.

  18. Noise suppressing capillary separation system

    DOEpatents

    Yeung, E.S.; Xue, Y.

    1996-07-30

    A noise-suppressing capillary separation system for detecting the real-time presence or concentration of an analyte in a sample is provided. The system contains a capillary separation means through which the analyte is moved, a coherent light source that generates a beam which is split into a reference beam and a sample beam that irradiate the capillary, and a detector for detecting the reference beam and the sample beam light that transmits through the capillary. The laser beam is of a wavelength effective to be absorbed by a chromophore in the capillary. The system includes a noise suppressing system to improve performance and accuracy without signal averaging or multiple scans. 13 figs.

  19. Geometry-induced capillary emptying.

    PubMed

    Rascón, Carlos; Parry, Andrew O; Aarts, Dirk G A L

    2016-10-24

    When a capillary is half-filled with liquid and turned to the horizontal, the liquid may flow out of the capillary or remain in it. For lack of a better criterion, the standard assumption is that the liquid will remain in a capillary of narrow cross-section, and will flow out otherwise. Here, we present a precise mathematical criterion that determines which of the two outcomes occurs for capillaries of arbitrary cross-sectional shape, and show that the standard assumption fails for certain simple geometries, leading to very rich and counterintuitive behavior. This opens the possibility of creating very sensitive microfluidic devices that respond readily to small physical changes, for instance, by triggering the sudden displacement of fluid along a capillary without the need of any external pumping.

  20. Biomedical applications of capillary electrophoresis

    NASA Astrophysics Data System (ADS)

    Kartsova, L. A.; Bessonova, E. A.

    2015-08-01

    The review deals with modern analytical approaches used in capillary electrophoresis for solving medical and biological problems: search for biomarkers of various diseases and rapid diagnosis based on characteristic profiles of biologically active compounds by capillary electrophoresis with mass spectrometric detection; monitoring of the residual drugs in biological fluids for evaluating the efficiency of drug therapy; testing of the enantiomeric purity of pharmaceutical products; the use of novel materials as components of stationary and pseudo-stationary phases in capillary electrophoresis and capillary electrochromatography to increase the selectivity of separation of components of complex matrices; and identification of various on-line preconcentration techniques to reduce the detection limits of biologically active analytes. A topical trend in capillary electrophoresis required in clinical practice, viz., the design of microfluidic systems, is discussed. The bibliography includes 173 references.

  1. High temperature ablative foam

    NASA Technical Reports Server (NTRS)

    Liu, Matthew T. (Inventor)

    1992-01-01

    An ablative foam composition is formed of approximately 150 to 250 parts by weight polymeric isocyanate having an isocyanate functionality of 2.6 to 3.2; approximately 15 to 30 parts by weight reactive flame retardant having a hydroxyl number range from 200-260; approximately 10 to 40 parts by weight non-reactive flame retardant; approximately 10 to 40 parts by weight nonhydrolyzable silicone copolymer having a hydroxyl number range from 75-205; and approximately 3 to 16 parts by weight amine initiated polyether resin having an isocyanate functionality greater than or equal to 3.0 and a hydroxyl number range from 400-800.

  2. Matricectomy and nail ablation.

    PubMed

    Baran, Robert; Haneke, Eckart

    2002-11-01

    Matricectomy refers to the complete extirpation of the nail matrix, resulting in permanent nail loss. Usually however, matricectomy is only partial, restricted to one or both lateral horns of the matrix. Nail ablation is the definitive removal of the entire nail organ. The most important common denominator in the successful matricectomy is the total removal or destruction of the matrix tissue. Matricectomy may be indicated for the management of onychauxis, onychogryphosis, congenital nail dystrophies, and chronic painful nail, such as recalcitrant ingrown toenail or split within the medial or lateral one-third of the nail.

  3. Laser ablation in analytical chemistry.

    PubMed

    Russo, Richard E; Mao, Xianglei; Gonzalez, Jhanis J; Zorba, Vassilia; Yoo, Jong

    2013-07-02

    In 2002, we wrote an Analytical Chemistry feature article describing the Physics of Laser Ablation in Microchemical Analysis. In line with the theme of the 2002 article, this manuscript discusses current issues in fundamental research, applications based on detecting photons at the ablation site (LIBS and LAMIS) and by collecting particles for excitation in a secondary source (ICP), and directions for the technology.

  4. Capillary ratchet: Hydrodynamics of capillary feeding in shorebirds

    NASA Astrophysics Data System (ADS)

    Prakash, Manu; Quere, David; Bush, John

    2008-03-01

    Bill morphologies are highly specialized to particular foraging strategies in birds, as is apparent from the large diversity of beak shapes observed in nature. Here we present an experimental and analytical study of capillary feeding in shorebirds. We highlight the critical role of contact angle hysteresis in capillary feeding. Our study provides a simple physical rationalization for the observation of multiple mandibular spreading cycles in feeding, necessary to overcome contact line resistance. We also find a unique geometrical optima in beak opening and closing angles for the most efficient drop transport. This capillary ratchet mechanism may also find applications in micro scale fluid transport, such as valveless pumping of fluid drops.

  5. Capillaries for use in a multiplexed capillary electrophoresis system

    DOEpatents

    Yeung, E.S.; Chang, H.T.; Fung, E.N.

    1997-12-09

    The invention provides a side-entry optical excitation geometry for use in a multiplexed capillary electrophoresis system. A charge-injection device is optically coupled to capillaries in the array such that the interior of a capillary is imaged onto only one pixel. In Sanger-type 4-label DNA sequencing reactions, nucleotide identification (``base calling``) is improved by using two long-pass filters to split fluorescence emission into two emission channels. A binary poly(ethyleneoxide) matrix is used in the electrophoretic separations. 19 figs.

  6. Capillaries for use in a multiplexed capillary electrophoresis system

    DOEpatents

    Yeung, Edward S.; Chang, Huan-Tsang; Fung, Eliza N.

    1997-12-09

    The invention provides a side-entry optical excitation geometry for use in a multiplexed capillary electrophoresis system. A charge-injection device is optically coupled to capillaries in the array such that the interior of a capillary is imaged onto only one pixel. In Sanger-type 4-label DNA sequencing reactions, nucleotide identification ("base calling") is improved by using two long-pass filters to split fluorescence emission into two emission channels. A binary poly(ethyleneoxide) matrix is used in the electrophoretic separations.

  7. Steady Capillary Driven Flow

    NASA Technical Reports Server (NTRS)

    Weislogel, Mark M.

    1996-01-01

    A steady capillary driven flow is developed for a liquid index in a circular tube which is partially coated with a surface modifier to produce a discontinuous wetting condition from one side of the tube to the other. The bulk flow is novel in that it is truly steady, and controlled solely by the physics associated with dynamic wetting. The influence of gravity on the flow is minimized through the use of small diameter tubes approximately O(1 mm) tested horizontally in a laboratory and larger tubes approximately O(10 mm) tested in the low gravity environment of a drop tower. Average steady velocities are predicted and compared against a large experimental data set which includes the effects of tube dimensions and fluid properties. The sensitivity of the velocity to surface cleanliness is dramatic and the advantages of experimentation in a microgravity environment are discussed.

  8. A capillary Archimedes' screw

    NASA Astrophysics Data System (ADS)

    Darbois Texier, Baptiste; Dorbolo, Stephane

    2014-11-01

    As used by Egyptians for irrigation and reported by Archimedes, a screw turning inside a hollow pipe can pull out a fluid againt gravity. At a centimetric scale, an analagous system can be found with a drop pending on a rotating spiral which is tilted toward the horizontal. The ascent of the drop to the top of the spiral is considered and a theoretical model based on geometrical considerations is proposed. The climb of the drop is limited by the fluid deposition on the screw at high capillary number and by a centrifugation phenomenon. We find out the range of fluid proprities and spiral characteristics for which an ascending motion of the drop is possible. Finally we discuss the efficiency of such system to extract a fluid from a bath at a centrimetric scale.

  9. Multidimensional capillary electrophoresis.

    PubMed

    Grochocki, Wojciech; Markuszewski, Michał J; Quirino, Joselito P

    2015-01-01

    Multidimensional separation where two or more orthogonal displacement mechanisms are combined is a promising approach to increase peak capacity in CE. The combinations allow dramatic improvement of analytical performance since the total peak capacity is given by a product of the peak capacities of all methods. The initial reports were concentrated on the construction of effective connections between capillaries for 2D analysis. Today, 2D and 3D CE systems are now able to separate real complex biological or environmental mixtures with good repeatability, improved resolution with minimal loss of sample. This review will present the developments in the field of multidimensional CE during the last 15 years. The endeavors in this specific field were on the development of interfaces, interface-free techniques including integrated separations, microdevices, and on-line sample concentration techniques to improve detection sensitivity.

  10. Simulation of Pellet Ablation

    NASA Astrophysics Data System (ADS)

    Parks, P. B.; Ishizaki, Ryuichi

    2000-10-01

    In order to clarify the structure of the ablation flow, 2D simulation is carried out with a fluid code solving temporal evolution of MHD equations. The code includes electrostatic sheath effect at the cloud interface.(P.B. Parks et al.), Plasma Phys. Contr. Fusion 38, 571 (1996). An Eulerian cylindrical coordinate system (r,z) is used with z in a spherical pellet. The code uses the Cubic-Interpolated Psudoparticle (CIP) method(H. Takewaki and T. Yabe, J. Comput. Phys. 70), 355 (1987). that divides the fluid equations into non-advection and advection phases. The most essential element of the CIP method is in calculation of the advection phase. In this phase, a cubic interpolated spatial profile is shifted in space according to the total derivative equations, similarly to a particle scheme. Since the profile is interpolated by using the value and the spatial derivative value at each grid point, there is no numerical oscillation in space, that often appears in conventional spline interpolation. A free boundary condition is used in the code. The possibility of a stationary shock will also be shown in the presentation because the supersonic ablation flow across the magnetic field is impeded.

  11. Spark discharge coupled laser multicharged ion source.

    PubMed

    Shaim, Md Haider A; Elsayed-Ali, Hani E

    2015-07-01

    A spark discharge is coupled to a laser multicharged ion source to enhance ion generation. The laser plasma triggers a spark discharge with electrodes located in front of the ablated target. For an aluminum target, the spark discharge results in significant enhancement in the generation of multicharged ions along with higher charge states than observed with the laser source alone. When a Nd:YAG laser pulse (wavelength 1064 nm, pulse width 7.4 ns, pulse energy 72 mJ, laser spot area on target 0.0024 cm(2)) is used, the total multicharged ions detected by a Faraday cup is 1.0 nC with charge state up to Al(3+). When the spark amplification stage is used (0.1 μF capacitor charged to 5.0 kV), the total charge measured increases by a factor of ∼9 with up to Al(6+) charge observed. Using laser pulse energy of 45 mJ, charge amplification by a factor of ∼13 was observed for a capacitor voltage of 4.5 kV. The spark discharge increases the multicharged ion generation without increasing target ablation, which solely results from the laser pulse. This allows for increased multicharged ion generation with relatively low laser energy pulses and less damage to the surface of the target.

  12. Instability of the capillary bridge

    NASA Astrophysics Data System (ADS)

    Pare, Gounseti; Hoepffner, Jerome

    2014-11-01

    Capillary adhesion is a physical mechanism that maintains two bodies in contact by capillarity through a liquid ligament. The capillary bridge is an idealization of this capillary adhesion. In this study we first focus on the classical case of the stability of the capillary bridge. Secondly we study a slightly more complex configuration, imagining a flow in the capillary bridge as in the case of the dynamics of the neck of a liquid ligament, in its withdrawal under the effect of capillarity. Inspired by the experiments on soap films of Plateau, the configuration analyzed consists of an initially axisymmetric, mass of fluid held by surface tension forces between two parallel, coaxial, solid pipes of the same diameter. The results presented are obtained by numerical simulations using the free software, Gerris Flow Solver. We first focus on the capillary Venturi. In the static configuration the stability diagram of the capillary bridge obtained is in perfect agreement with the results of Lev A. Slobozhanin. In the dynamic case we develop a matlab code based on the one dimensional equations of Eggers and Dupont. The comparison of the bifurcation diagram obtained and the numerical simulations shows a good agreement.

  13. Inertial Rise in Short Capillaries

    NASA Astrophysics Data System (ADS)

    Shardt, Orest; Waghmare, Prashant; Mitra, Sushanta; Derksen, Jos

    2013-11-01

    We investigate the primarily inertial rise of liquid in vertical glass capillaries that are shorter than the equilibrium rise height (Jurin height). We focus on the behavior of the liquid upon reaching the top of the capillary and use high-speed imaging to observe the motion of the liquid-air interface with high spatial and temporal resolution. We examine the dependence of the interface behavior on the meniscus speed and capillary height and describe a new phenomenon. Upon reaching the upper edge of a sufficiently short capillary, the meniscus inverts, rises upward, and bulges out radially. The bulging liquid then wets the external surface of the capillary and slides down. The meniscus inside the capillary retracts, falling below the upper edge, and then oscillates vertically with decaying amplitude, inverting several times before reaching a steady shape. A theoretical analysis is used to interpret the conditions required for this phenomenon to occur. A key assumption in the analysis is that the transient flow is inertial and therefore the capillary driving force is balanced by the weight and inertia of the rising liquid column while viscous forces are comparatively small. The analysis points to the possibility of obtaining previously-unseen behavior under reduced gravity.

  14. Electrospraying from nanofluidic capillary slot

    NASA Astrophysics Data System (ADS)

    Arscott, Steve; Troadec, David

    2005-09-01

    We present here an original electrospray emitter tip based on a nanofluidic capillary slot. The nanofabrication involves focused ion beam etching to form the slot which has a cross-section of 50×300nm and a length of 4μm. The liquid is deformed into the nanofluidic capillary slot by capillary action; the electrospray is produced by the application of a low voltage. Using a water-methanol-formic acid solution, we have observed an electrospray onset voltage of 125V. At a measured electrospray current of 1nA, the unforced flow-rate is estimated to be 110pLmin-1.

  15. Integrated multiplexed capillary electrophoresis system

    DOEpatents

    Yeung, Edward S.; Tan, Hongdong

    2002-05-14

    The present invention provides an integrated multiplexed capillary electrophoresis system for the analysis of sample analytes. The system integrates and automates multiple components, such as chromatographic columns and separation capillaries, and further provides a detector for the detection of analytes eluting from the separation capillaries. The system employs multiplexed freeze/thaw valves to manage fluid flow and sample movement. The system is computer controlled and is capable of processing samples through reaction, purification, denaturation, pre-concentration, injection, separation and detection in parallel fashion. Methods employing the system of the invention are also provided.

  16. Thermal response and ablation characteristics of light weight ceramic ablators

    NASA Technical Reports Server (NTRS)

    Tran, Huy K.; Rasky, Daniel J.; Esfahani, Lili

    1993-01-01

    An account is given of the thermal performance and ablation characteristics of the NASA-Ames Lightweight Ceramic Ablators (LCAs) in supersonic, high-enthalpy convective environments, which use low density ceramic or carbon fiber matrices as substrates for main structural support, with organic resin fillers. LCA densities are in the 0.224-1.282 g/cu cm range. In-depth temperature data have been obtained to determine thermal penetration depths and conductivity. The addition of SiC and PPMA is noted to significantly improve the ablation performance of LCAs with silica substrates. Carbon-based LCAs are the most mass-efficient at high flux levels.

  17. Analysis of Capillary Rise in Asymmetric Branch-Like Capillary

    NASA Astrophysics Data System (ADS)

    Li, Caoxiong; Shen, Yinghao; Ge, Hongkui; Yang, Zhihui; Su, Shuai; Ren, Kai; Huang, Heyu

    2016-05-01

    Transport in porous media is common in nature, attracting many attentions for a long time. Tree-like network model is often used as a simplification for porous space, expressing the complexity of pore spaces instead of capillary bundle. To investigate spontaneous imbibition characteristics in this network, a dynamic asymmetric branch-like capillary model is used to represent basic network structure, using fractal method to represent tortuosity. This work investigates the influence of parameters on imbibition process in the branch-like capillary model. An analytical equation for the imbibition mass versus time is derived. Parameters from capillary structures to liquid properties are taken into account and analyzed based on the numerical solution of the equation. It is found that the imbibition process in asymmetric branch-like capillary model can be recognized by four sections and brunching tubes are positive for imbibition process. Concomitantly, meniscus arrest event is simulated and discussed. Moreover, the influence of parameters on imbibition process is discussed. These parameters can be classified as static and dynamic. Static parameters mainly change the capillary force, which are related to the ultimate imbibition mass or imbibition ability, while dynamic parameters mainly have influence on resistance of flowing fluid, which are related to the imbibition speed in the imbibition process.

  18. Capillary electrophoresis electrospray ionization mass spectrometry interface

    DOEpatents

    Smith, Richard D.; Severs, Joanne C.

    1999-01-01

    The present invention is an interface between a capillary electrophoresis separation capillary end and an electrospray ionization mass spectrometry emitter capillary end, for transporting an anolyte sample from a capillary electrophoresis separation capillary to a electrospray ionization mass spectrometry emitter capillary. The interface of the present invention has: (a) a charge transfer fitting enclosing both of the capillary electrophoresis capillary end and the electrospray ionization mass spectrometry emitter capillary end; (b) a reservoir containing an electrolyte surrounding the charge transfer fitting; and (c) an electrode immersed into the electrolyte, the electrode closing a capillary electrophoresis circuit and providing charge transfer across the charge transfer fitting while avoiding substantial bulk fluid transfer across the charge transfer fitting. Advantages of the present invention have been demonstrated as effective in providing high sensitivity and efficient analyses.

  19. Capillary fracturing in granular media.

    PubMed

    Holtzman, Ran; Szulczewski, Michael L; Juanes, Ruben

    2012-06-29

    We study the displacement of immiscible fluids in deformable, noncohesive granular media. Experimentally, we inject air into a thin bed of water-saturated glass beads and observe the invasion morphology. The control parameters are the injection rate, the bead size, and the confining stress. We identify three invasion regimes: capillary fingering, viscous fingering, and "capillary fracturing," where capillary forces overcome frictional resistance and induce the opening of conduits. We derive two dimensionless numbers that govern the transition among the different regimes: a modified capillary number and a fracturing number. The experiments and analysis predict the emergence of fracturing in fine-grained media under low confining stress, a phenomenon that likely plays a fundamental role in many natural processes such as primary oil migration, methane venting from lake sediments, and the formation of desiccation cracks.

  20. Capillary Fracturing in Granular Media

    NASA Astrophysics Data System (ADS)

    Holtzman, Ran; Szulczewski, Michael L.; Juanes, Ruben

    2012-06-01

    We study the displacement of immiscible fluids in deformable, noncohesive granular media. Experimentally, we inject air into a thin bed of water-saturated glass beads and observe the invasion morphology. The control parameters are the injection rate, the bead size, and the confining stress. We identify three invasion regimes: capillary fingering, viscous fingering, and “capillary fracturing,” where capillary forces overcome frictional resistance and induce the opening of conduits. We derive two dimensionless numbers that govern the transition among the different regimes: a modified capillary number and a fracturing number. The experiments and analysis predict the emergence of fracturing in fine-grained media under low confining stress, a phenomenon that likely plays a fundamental role in many natural processes such as primary oil migration, methane venting from lake sediments, and the formation of desiccation cracks.

  1. DNA typing by capillary electrophoresis

    SciTech Connect

    Zhang, N.

    1997-10-08

    Capillary electrophoresis is becoming more and more important in nucleic acid analysis including DNA sequencing, typing and disease gene measurements. This work summarized the background of DNA typing. The recent development of capillary electrophoresis was also discussed. The second part of the thesis showed the principle of DNA typing based on using the allelic ladder as the absolute standard ladder in capillary electrophoresis system. Future work will be focused on demonstrating DNA typing on multiplex loci and examples of disease diagnosis in the on-line format of PCR-CE. Also capillary array electrophoresis system should allow high throughput, fast speed DNA typing. Only the introduction and conclusions for this report are available here. A reprint was removed for separate processing.

  2. [New techniques of tumor ablation (microwaves, electroporation)].

    PubMed

    de Baere, T

    2011-09-01

    Since the introduction of radiofrequency tumor ablation of liver tumors in the late 1990s, local destructive therapies have been applied to lung, renal and bone lesions. In addition, new techniques have been introduced to compensate for the limitations of radiofrequency ablation, namely the reduced rate of complete ablation for tumors larger than 3 cm and tumors near vessels larger than 3 mm. Microwave ablation is currently evolving rapidly. While it is a technique based on thermal ablation similar to radiofrequency ablation, there are significant differences between both techniques. Electroporation, of interest because of the non-thermal nature of the ablation process, also is under evaluation.

  3. Ablative heat shield design for space shuttle

    NASA Technical Reports Server (NTRS)

    Seiferth, R. W.

    1973-01-01

    Ablator heat shield configuration optimization studies were conducted for the orbiter. Ablator and reusable surface insulation (RSI) trajectories for design studies were shaped to take advantage of the low conductance of ceramic RSI and high temperature capability of ablators. Comparative weights were established for the RSI system and for direct bond and mechanically attached ablator systems. Ablator system costs were determined for fabrication, installation and refurbishment. Cost penalties were assigned for payload weight penalties, if any. The direct bond ablator is lowest in weight and cost. A mechanically attached ablator using a magnesium subpanel is highly competitive for both weight and cost.

  4. Magnetic and robotic navigation for catheter ablation: "joystick ablation".

    PubMed

    Ernst, Sabine

    2008-10-01

    Catheter ablation has become the treatment of choice to cure various arrhythmias in the last decades. The newest advancement of this general concept is made on the navigation ability using remote-controlled ablation catheters. This review summarizes the concept of the two currently available systems, followed by a critical review of the published clinical reports for each system, respectively. Despite the limited amount of data, an attempt to compare the two systems is made.

  5. Investigation of the Plasma Properties of Surface Discharges.

    DTIC Science & Technology

    1985-09-30

    rare gases at high pressure under similar discharge conditions. Andreev’s model shows that the radiation flux can significantly alter the shock-wave...capacitance of the substrate, the gas atmosphere and pressures and the ablation mode of the substrate. an UNCLASSIFIED SECURITY CLASSIFICATION OF THIS PAGE...D = 7(3) x 104 cm/sec for discharges in ArCXe) gas at 1 atm pressure and a discharge power density of G - 5 x 105 W/cm2. Spectroscopic studies were

  6. TPS Ablator Technologies for Interplanetary Spacecraft

    NASA Technical Reports Server (NTRS)

    Curry, Donald M.

    2004-01-01

    This slide presentation reviews the status of Thermal Protection System (TPS) Ablator technologies and the preparation for use in interplanetary spacecraft. NASA does not have adequate TPS ablatives and sufficient selection for planned missions. It includes a comparison of shuttle and interplanetary TPS requirements, the status of mainline TPS charring ablator materials, a summary of JSC SBIR accomplishments in developing advanced charring ablators and the benefits of SBIR Ablator/fabrication technology.

  7. Tennis elbow surgery - discharge

    MedlinePlus

    ... epicondylitis surgery - discharge; Lateral tendinosis surgery - discharge; Lateral tennis elbow surgery - discharge ... long as you are told. This helps ensure tennis elbow will not return. You may be prescribed a ...

  8. Eye muscle repair - discharge

    MedlinePlus

    ... Lazy eye repair - discharge; Strabismus repair - discharge; Extraocular muscle surgery - discharge ... You or your child had eye muscle repair surgery to correct eye muscle ... term for crossed eyes is strabismus. Children most often ...

  9. Asthma - child - discharge

    MedlinePlus

    Pediatric asthma - discharge; Wheezing - discharge; Reactive airway disease - discharge ... Your child has asthma , which causes the airways of the lungs to swell and narrow. In the hospital, the doctors and nurses helped ...

  10. Gastric bypass surgery - discharge

    MedlinePlus

    Bariatric surgery - gastric bypass - discharge; Roux-en-Y gastric bypass - discharge; Gastric bypass - Roux-en-Y - discharge; Obesity ... Gloy VL, Briel M, Bhatt DL, et al. Bariatric surgery versus non-surgical treatment for obesity: a systematic ...

  11. Numerical studies of wall-plasma interactions and ionization phenomena in an ablative pulsed plasma thruster

    NASA Astrophysics Data System (ADS)

    Yang, Lei; Zeng, Guangshang; Tang, Haibin; Huang, Yuping; Liu, Xiangyang

    2016-07-01

    Wall-plasma interactions excited by ablation controlled arcs are very critical physical processes in pulsed plasma thrusters (PPTs). Their effects on the ionization processes of ablated vapor into discharge plasma directly determine PPT performances. To reveal the physics governing the ionization phenomena in PPT discharge, a modified model taking into account the pyrolysis effect of heated polytetrafluoroethylene propellant on the wall-plasma interactions was developed. The feasibility of the modified model was analyzed by creating a one-dimensional simulation of a rectangular ablative PPT. The wall-plasma interaction results based on this modified model were found to be more realistic than for the unmodified model; this reflects the dynamic changes of the inflow parameters during discharge in our model. Furthermore, the temporal and spatial variations of the different plasma species in the discharge chamber were numerically studied. The numerical studies showed that polytetrafluoroethylene plasma was mainly composed of monovalent ions; carbon and fluorine ions were concentrated in the upstream and downstream discharge chamber, respectively. The results based on this modified model were in good agreement with the experimental formation times of the various plasma species. A large number of short-lived and highly ionized carbon and fluorine species (divalent and trivalent ions) were created during initial discharge. These highly ionized species reached their peak density earlier than the singly ionized species.

  12. Lung radiofrequency and microwave ablation: a review of indications, techniques and post-procedural imaging appearances.

    PubMed

    Smith, S L; Jennings, P E

    2015-02-01

    Lung ablation can be used to treat both primary and secondary thoracic malignancies. Evidence to support its use, particularly for metastases from colonic primary tumours, is now strong, with survival data in selected cases approaching that seen after surgery. Because of this, the use of ablative techniques (particularly thermal ablation) is growing and the Royal College of Radiologists predict that the number of patients who could benefit from such treatment may reach in excess of 5000 per year in the UK. Treatment is often limited to larger regional centres, and general radiologists often have limited awareness of the current indications and the techniques involved. Furthermore, radiologists without any prior experience are frequently expected to interpret post-treatment imaging, often performed in the context of acute complications, which have occurred after discharge. This review aims to provide an overview of the current indications for pulmonary ablation, together with the techniques involved and the range of post-procedural appearances.

  13. Effects of insulator ablation on the operation of a quasi-steady MPD arc

    NASA Technical Reports Server (NTRS)

    Boyle, M. J.; Jahn, R. G.

    1973-01-01

    Multimegawatt operation of quasi-steady MPD arcjets can involve serious ablation of the insulator surfaces within the arc discharge chamber. Various degrees of insulator ablation manifest themselves by significantly perturbing the voltage-current characteristics and the exhaust velocity profiles. Voltage-current characteristics for two different insulator materials, Plexiglas and boron nitride, are interpreted in terms of an empirical Ohm's law. Use of the refractory insulator material eliminates the ablation-dominated nature of the terminal voltage, but the exhaust stream is still disturbed by insulator material. An Alfven critical velocity model can be applied to this influence of insulator ablation on exhaust velocity. Appropriate changes in the propellant injection geometry eliminate this influence and result in arcjet operation which is independent of insulator material. A particular combination of propellant injection geometries reduces the terminal voltage for a given current and mass flow while maintaining insulator-independent operation, thus implying an improvement in the overall efficiency of the device.

  14. Lung radiofrequency and microwave ablation: a review of indications, techniques and post-procedural imaging appearances

    PubMed Central

    Jennings, P E

    2015-01-01

    Lung ablation can be used to treat both primary and secondary thoracic malignancies. Evidence to support its use, particularly for metastases from colonic primary tumours, is now strong, with survival data in selected cases approaching that seen after surgery. Because of this, the use of ablative techniques (particularly thermal ablation) is growing and the Royal College of Radiologists predict that the number of patients who could benefit from such treatment may reach in excess of 5000 per year in the UK. Treatment is often limited to larger regional centres, and general radiologists often have limited awareness of the current indications and the techniques involved. Furthermore, radiologists without any prior experience are frequently expected to interpret post-treatment imaging, often performed in the context of acute complications, which have occurred after discharge. This review aims to provide an overview of the current indications for pulmonary ablation, together with the techniques involved and the range of post-procedural appearances. PMID:25465192

  15. Threshold capillary pressure in capillaries with curved sides

    NASA Astrophysics Data System (ADS)

    Lago, Marcelo; Araujo, Mariela

    2003-03-01

    Modeling of fluid flow through permeable media is of great importance in assessing the performance of both hydrocarbon reservoirs and aquifers. In this process, network models based on cylindrical capillaries with circular cross sections are frequently used. This type of capillaries are not able to reproduce interesting physical phenomena observed in the experiments, for example, situations where there is flow by films with the wetting fluid occupying the crevices and wedges of the structure. We present an analysis of the behavior of the capillary pressure of a droplet of non-wetting fluid with an infinite length, inside objects of cylindrical symmetry with curved sides. The calculation is based on a method proposed by Mayer and Stowe and Princen (MS-P). Different capillary geometries are considered, and the behavior of the capillary pressure and transversal fluid saturation as a function of the shape factor is studied. The results found either analytically or numerically, allow to understand the relation between geometry and flow properties, and helps in the building of more realistic pore network models for flow studies at the pore scale.

  16. Two-dimensional capillary electrophoresis using tangentially connected capillaries.

    PubMed

    Sahlin, Eskil

    2007-06-22

    A novel type of fused silica capillary system is described where channels with circular cross-sections are tangentially in contact with each other and connected through a small opening at the contact area. Since the channels are not crossing each other in the same plane, the capillaries can easily be filled with different solutions, i.e. different solutions will be in contact with each other at the contact point. The system has been used to perform different types of two-dimensional separations and the complete system is fully automated where a high voltage switch is used to control the location of the high voltage in the system. Using two model compounds it is demonstrated that a type of two-dimensional separation can be performed using capillary zone electrophoresis at two different pH values. It is also shown that a compound with acid/base properties can be concentrated using a dynamic pH junction mechanism when transferred from the first separation to the second separation. In addition, the system has been used to perform a comprehensive two-dimensional capillary electrophoresis separation of tryptic digest of bovine serum albumin using capillary zone electrophoresis followed by micellar electrokinetic chromatography.

  17. Prostate brachytherapy - discharge

    MedlinePlus

    Implant therapy - prostate cancer - discharge; Radioactive seed placement - discharge ... You had a procedure called brachytherapy to treat prostate cancer. Your treatment lasted 30 minutes or more, depending ...

  18. ACL reconstruction - discharge

    MedlinePlus

    Anterior cruciate ligament reconstruction - discharge; ACL reconstruction - discharge ... had surgery to reconstruct your anterior cruciate ligament (ACL). The surgeon drilled holes in the bones of ...

  19. Study of capillary experiments and hydrologic factors under subsurface drip irrigation with fractal theory

    NASA Astrophysics Data System (ADS)

    Zhou, W.; Cao, L.

    2012-11-01

    Soil spatial variability is one of the primary environmental factors that influences the hydraulic factors and technical indicators of subsurface drip irrigation (SDI), whose emitters are buried in the soil. This paper aimed at evaluating these effects of soil spatial variability on hydrologic factors under SDI. And some SDI emitter and capillary experiments were designed to obtain test data and distribution of pressure and emitter discharge. First, The results of labyrinth non-turbulent mosaic drip emitter test and fractal theory were used to research the fractal and quantitative relationship between single emitter hydrologic factors and soil physical parameters; and then, the capillary experiments and the relationship among hydrologic factors of capillary were used to analyze the fractal and quantitative relationship between hydrologic factors of capillary and soil physical parameters, which explained the inner relationship between spatial variability of soil and hydrologic factors of filed pipeline network under SDI, and provide theory support for the plan, design, management and production of SDI.

  20. Capillary Suction Time. Operational Control Tests for Wastewater Treatment Facilities. Instructor's Manual [and] Student Workbook.

    ERIC Educational Resources Information Center

    Wooley, John F.

    Capillary suction time is time required for the liquid phase of a treated sludge to travel through 1 centimeter of media (blotter or filter paper). Designed for individuals who have completed National Pollutant Discharge Elimination System (NPDES) level 1 laboratory training skills, this module provides waste water treatment plant operators with…

  1. Capillary wave measurements on helically-supported capillary channels

    NASA Astrophysics Data System (ADS)

    Chandurwala, Fahim; Thiessen, David

    2010-10-01

    NASA is considering power generation by the Rankine cycle to save weight on long-duration manned missions to the moon or Mars. Phase separation technology is critical to this process in microgravity. Arrays of capillary channels might be useful for filtering liquid drops from a flowing vapor. The efficiency of droplet capture by a helically-supported capillary channel is being studied. A droplet impinging on the channel launches capillary waves that propagate down the channel helping to dissipate some of the drop's kinetic energy. High-speed video of the channel combined with image processing allows for measurement of the amplitude and speed of the wave packets. Increasing the pitch of the support structure decreases the wave speed. An understanding of the dynamic response of the channel to drop impact is a first step in predicting drop-capture efficiency.

  2. Capillary imbibition in parallel tubes

    NASA Astrophysics Data System (ADS)

    McRae, Oliver; Ramakrishnan, T. S.; Bird, James

    2016-11-01

    In modeling porous media two distinct approaches can be employed; the sample can be examined holistically, using global variables such as porosity, or it can be treated as a network of capillaries connected in series to various intermediate reservoirs. In forced imbibition this series-based description is sufficient to characterize the flow, due to the presence of an externally maintained pressure difference. However, in spontaneous imbibition, flow is driven by an internal capillary pressure, making it unclear whether a series-based model is appropriate. In this talk, we show using numerical simulations the dynamics of spontaneous imbibition in concentrically arranged capillary tubes. This geometry allows both tubes access to a semi-infinite reservoir but with inlets in close enough proximity to allow for interference. We compare and contrast the results of our simulations with theory and previous experiments. Schlumberger-Doll Research.

  3. Non-Aqueous Capillary Electrophoresis

    NASA Astrophysics Data System (ADS)

    Szumski, Michał; Buszewski, Bogusław

    Non-aqueous capillary electrophoresis and capillary electrochromatography are special variants of these techniques. Here, organic solvents or their mixtures with or without dissolved electrolytes are used as separation buffer or mobile phase, respectively. The most important features of non-aqueous systems are: better solubility of more hydrophobic ionic substances (many natural products) than in water, much less current and Joule heating allows for using highly concentrated buffers and/or larger capillary internal diameters, polar interactions are enhanced in organic solvents which is often highly advantageous in chiral separation systems. This chapter presents most frequently used solvents, their properties, as well as shows pH* scale which is often used in non-aqueous systems.

  4. Decay of capillary wave turbulence.

    PubMed

    Deike, Luc; Berhanu, Michael; Falcon, Eric

    2012-06-01

    We report on the observation of freely decaying capillary wave turbulence on the surface of a fluid. The capillary wave turbulence spectrum decay is found to be self-similar in time with the same power law exponent as the one found in the stationary regime, in agreement with weak turbulence predictions. The amplitude of all Fourier modes are found to decrease exponentially with time at the same damping rate. The longest wavelengths involved in the system are shown to be damped by a viscous surface boundary layer. These long waves play the role of an energy source during the decay that sustains nonlinear interactions to keep capillary waves in a wave turbulent state.

  5. Mass Spectrometric Imaging Using Laser Ablation and Solvent Capture by Aspiration (LASCA)

    NASA Astrophysics Data System (ADS)

    Brauer, Jonathan I.; Beech, Iwona B.; Sunner, Jan

    2015-09-01

    A novel interface for ambient, laser ablation-based mass spectrometric imaging (MSI) referred to as laser ablation and solvent capture by aspiration (LASCA) is presented and its performance demonstrated using selected, unaltered biological materials. LASCA employs a pulsed 2.94 μm laser beam for specimen ablation. Ablated materials in the laser plumes are collected on a hanging solvent droplet with electric field-enhanced trapping, followed by aspiration of droplets and remaining plume material in the form of a coarse aerosol into a collection capillary. The gas and liquid phases are subsequently separated in a 10 μL-volume separatory funnel, and the solution is analyzed with electrospray ionization in a high mass resolution Q-ToF mass spectrometer. The LASCA system separates the sampling and ionization steps in MSI and combines high efficiencies of laser plume sampling and of electrospray ionization (ESI) with high mass resolution MS. Up to 2000 different compounds are detected from a single ablation spot (pixel). Using the LASCA platform, rapid (6 s per pixel), high sensitivity, high mass-resolution ambient imaging of "as-received" biological material is achieved routinely and reproducibly.

  6. Capillary interactions in Pickering emulsions

    NASA Astrophysics Data System (ADS)

    Guzowski, J.; Tasinkevych, M.; Dietrich, S.

    2011-09-01

    The effective capillary interaction potentials for small colloidal particles trapped at the surface of liquid droplets are calculated analytically. Pair potentials between capillary monopoles and dipoles, corresponding to particles floating on a droplet with a fixed center of mass and subjected to external forces and torques, respectively, exhibit a repulsion at large angular separations and an attraction at smaller separations, with the latter resembling the typical behavior for flat interfaces. This change of character is not observed for quadrupoles, corresponding to free particles on a mechanically isolated droplet. The analytical results are compared with the numerical minimization of the surface free energy of the droplet in the presence of spherical or ellipsoidal particles.

  7. Capillary haemangioma of the testis

    PubMed Central

    Mazal, P; Kratzik, C; Kain, R; Susani, M

    2000-01-01

    A case of testicular capillary haemangioma is reported and the importance of intraoperative examination of this very rare lesion emphasised. Capillary haemangioma of the testis can be similar to malignant testicular tumours on clinical presentation, as well as on ultrasonography and magnetic resonance imaging, and therefore should be included in the intraoperative differential diagnosis. Because of the benign nature of this lesion, conservative surgical treatment by means of tumour enucleation with preservation of the testis is possible, if intraoperative examination of frozen sections of representative tissue can be performed. Key Words: testis • haemangioma PMID:11002773

  8. Nonsteady Flow in Capillary Tubes

    NASA Astrophysics Data System (ADS)

    Hara, Ayako

    2000-03-01

    Surface phenomena in the field of electron devices and the problem of how long. It takes plants to absorb water during their growth in hydroponic cultivation is attraching the attention of riseachers. However, the related study of non-steady flow in capillary tubes has a number of issues that require investigation. In response to this situation, we made attempted to assess nonsteady fiow in capillary tubes, the liquid rise time and other issues, using a motion equation that takes factors including the friction force of the tube and the surface tension into consideration.

  9. Revised Capillary Breakup Rheometer Method

    NASA Astrophysics Data System (ADS)

    Lu, Louise; Schultz, William; Solomon, Michael

    2014-11-01

    Rather than integrate the one-dimensional equation of motion for a capillary breakup rheometer, we take the axial derivative of that equation. This avoids the determination of the axial force with all of its complications and correction factors. The resulting evolutionary equation that involves either two or four derivatives of the capillary radius as a function of the axial coordinate determines the ratio of elongational viscosity to surface tension coefficient. We examine several silicone and olive oils to show the accuracy of the method for Newtonian fluids. We will discuss our surface tension measurement techniques and briefly describe measurements of viscoelastic materials, including saliva.

  10. UV-laser-assisted modification of poly(methyl methacrylate) and its application to capillary-driven-flow immunoassay

    NASA Astrophysics Data System (ADS)

    Fuchiwaki, Y.; Takaoka, H.

    2015-07-01

    A concave microchannel surface was formed by nanosecond pulse laser ablation to allow antibody immobilization on a capillary flow immunoassay chip. Microscopic analysis showed that UV laser ablation of poly(methyl methacrylate) at 193 nm and 1.76 J · cm-2 allowed excellent immobilization of Cy5 conjugated antibody. The concave structure was 10 µm deep and 260 µm wide and supported uniform antibody printing on the microchannel surface. The characteristics of immobilized antibodies on this surface and on a commercially available polymer coating were comparable. Quantitative analysis of procollagen type I C-peptide (PICP) at different concentrations provided a linear relationship in the range 0-600 ng ml-1 PICP, which is sufficient for clinical estimation of PICP in the blood. The results may provide a new benchmark for a mechatronic antibody immobilization-based capillary flow immunoassay chip.

  11. Femtosecond laser ablation of enamel

    NASA Astrophysics Data System (ADS)

    Le, Quang-Tri; Bertrand, Caroline; Vilar, Rui

    2016-06-01

    The surface topographical, compositional, and structural modifications induced in human enamel by femtosecond laser ablation is studied. The laser treatments were performed using a Yb:KYW chirped-pulse-regenerative amplification laser system (560 fs and 1030 nm) and fluences up to 14 J/cm2. The ablation surfaces were studied by scanning electron microscopy, grazing incidence x-ray diffraction, and micro-Raman spectroscopy. Regardless of the fluence, the ablation surfaces were covered by a layer of resolidified material, indicating that ablation is accompanied by melting of hydroxyapatite. This layer presented pores and exploded gas bubbles, created by the release of gaseous decomposition products of hydroxyapatite (CO2 and H2O) within the liquid phase. In the specimen treated with 1-kHz repetition frequency and 14 J/cm2, thickness of the resolidified material is in the range of 300 to 900 nm. The micro-Raman analysis revealed that the resolidified material contains amorphous calcium phosphate, while grazing incidence x-ray diffraction analysis allowed detecting traces of a calcium phosphate other than hydroxyapatite, probably β-tricalcium phosphate Ca3), at the surface of this specimen. The present results show that the ablation of enamel involves melting of enamel's hydroxyapatite, but the thickness of the altered layer is very small and thermal damage of the remaining material is negligible.

  12. Laser ablation studies of concrete

    SciTech Connect

    Savina, M.; Xu, Z.; Wang, Y.; Reed, C.; Pellin, M.

    1999-10-20

    Laser ablation was studied as a means of removing radioactive contaminants from the surface and near-surface regions of concrete. The authors present the results of ablation tests on cement and concrete samples using a 1.6 kW pulsed Nd:YAG laser with fiber optic beam delivery. The laser-surface interaction was studied using cement and high density concrete as targets. Ablation efficiency and material removal rates were determined as functions of irradiance and pulse overlap. Doped samples were also ablated to determine the efficiency with which surface contaminants were removed and captured in the effluent. The results show that the cement phase of the material melts and vaporizes, but the aggregate portion (sand and rock) fragments. The effluent consists of both micron-size aerosol particles and chunks of fragmented aggregate material. Laser-induced optical emission spectroscopy was used to analyze the surface during ablation. Analysis of the effluent showed that contaminants such as cesium and strontium were strongly segregated into different regions of the particle size distribution of the aerosol.

  13. Fragmentation and ablation during entry

    SciTech Connect

    Canavan, G.H.

    1997-09-01

    This note discusses objects that both fragment and ablate during entry, using the results of previous reports to describe the velocity, pressure, and fragmentation of entering objects. It shows that the mechanisms used there to describe the breakup of non-ablating objects during deceleration remain valid for most ablating objects. It treats coupled fragmentation and ablation during entry, building on earlier models that separately discuss the entry of objects that are hard, whose high heat of ablation permits little erosion, and those who are strong whose strength prevents fragmentation, which are discussed in ``Radiation from Hard Objects,`` ``Deceleration and Radiation of Strong, Hard, Asteroids During Atmospheric Impact,`` and ``Meteor Signature Interpretation.`` This note provides a more detailed treatment of the further breakup and separation of fragments during descent. It replaces the constraint on mass per unit area used earlier to determine the altitude and magnitude of peak power radiation with a detailed analytic solution of deceleration. Model predictions are shown to be in agreement with the key features of numerical calculations of deceleration. The model equations are solved for the altitudes of maximum radiation, which agree with numerical integrations. The model is inverted analytically to infer object size and speed from measurements of peak power and altitude to provide a complete model for the approximate inversion of meteor data.

  14. Thermal ablation of lung tumors.

    PubMed

    McTaggart, Ryan A; Dupuy, Damian E

    2007-06-01

    Thermal ablation can be applied to treat any thoracic malignancy: primary lung cancers, recurrent primary lung cancers, metastatic disease, chest wall masses, and painful, bony metastases. Since the first reported use of thermal ablation for lung cancer in 2000 there has been an explosive use of the procedure, and by 2010 the number of procedures to treat thoracic malignancy is expected to exceed 150,000 per year. Presently, thermal ablation is best used for patients with early-stage lung cancers in patients who are not surgical candidates, patients with small and favorably located pulmonary metastases, and patients in whom palliation of tumor-related symptoms is the goal. Radiofrequency ablation, microwave ablation, and cryoablation are novel treatment modalities for lung cancer and can safely accomplish tumor destruction and even complete eradication of tumor in patients who are not candidates for surgical resection. In this article, we discuss technical considerations for each modality and the periprocedure and postprocedure management of patients with this disease.

  15. GAS DISCHARGE DEVICES

    DOEpatents

    Arrol, W.J.; Jefferson, S.

    1957-08-27

    The construction of gas discharge devices where the object is to provide a gas discharge device having a high dark current and stabilized striking voltage is described. The inventors have discovered that the introduction of tritium gas into a discharge device with a subsequent electrical discharge in the device will deposit tritium on the inside of the chamber. The tritium acts to emit beta rays amd is an effective and non-hazardous way of improving the abovementioned discharge tube characteristics

  16. Multiplexed fluorescence detector system for capillary electrophoresis

    DOEpatents

    Yeung, Edward S.; Taylor, John A.

    1996-03-12

    A fluorescence detection system for capillary electrophoresis is provided wherein the detection system can simultaneously excite fluorescence and substantially simultaneously monitor separations in multiple capillaries. This multiplexing approach involves laser irradiation of a sample in a plurality of capillaries through optical fibers that are coupled individually with the capillaries. The array is imaged orthogonally through a microscope onto a charge-coupled device camera for signal analysis.

  17. Multiplexed fluorescence detector system for capillary electrophoresis

    DOEpatents

    Yeung, Edward S.; Taylor, John A.

    1994-06-28

    A fluorescence detection system for capillary electrophoresis is provided wherein the detection system can simultaneously excite fluorescence and substantially simultaneously monitor separations in multiple capillaries. This multiplexing approach involves laser irradiation of a sample in a plurality of capillaries through optical fibers that are coupled individually with the capillaries. The array is imaged orthogonally through a microscope onto a charge-coupled device camera for signal analysis.

  18. Multiplexed fluorescence detector system for capillary electrophoresis

    DOEpatents

    Yeung, E.S.; Taylor, J.A.

    1994-06-28

    A fluorescence detection system for capillary electrophoresis is provided wherein the detection system can simultaneously excite fluorescence and substantially simultaneously monitor separations in multiple capillaries. This multiplexing approach involves laser irradiation of a sample in a plurality of capillaries through optical fibers that are coupled individually with the capillaries. The array is imaged orthogonally through a microscope onto a charge-coupled device camera for signal analysis. 14 figures.

  19. Multiplexed fluorescence detector system for capillary electrophoresis

    DOEpatents

    Yeung, E.S.; Taylor, J.A.

    1996-03-12

    A fluorescence detection system for capillary electrophoresis is provided wherein the detection system can simultaneously excite fluorescence and substantially simultaneously monitor separations in multiple capillaries. This multiplexing approach involves laser irradiation of a sample in a plurality of capillaries through optical fibers that are coupled individually with the capillaries. The array is imaged orthogonally through a microscope onto a charge-coupled device camera for signal analysis. 14 figs.

  20. Theoretical Modeling for Hepatic Microwave Ablation

    PubMed Central

    Prakash, Punit

    2010-01-01

    Thermal tissue ablation is an interventional procedure increasingly being used for treatment of diverse medical conditions. Microwave ablation is emerging as an attractive modality for thermal therapy of large soft tissue targets in short periods of time, making it particularly suitable for ablation of hepatic and other tumors. Theoretical models of the ablation process are a powerful tool for predicting the temperature profile in tissue and resultant tissue damage created by ablation devices. These models play an important role in the design and optimization of devices for microwave tissue ablation. Furthermore, they are a useful tool for exploring and planning treatment delivery strategies. This review describes the status of theoretical models developed for microwave tissue ablation. It also reviews current challenges, research trends and progress towards development of accurate models for high temperature microwave tissue ablation. PMID:20309393

  1. Image-guided ablation of adrenal lesions.

    PubMed

    Yamakado, Koichiro

    2014-06-01

    Although laparoscopic adrenalectomy has remained the standard of care for the treatment for adrenal tumors, percutaneous image-guided ablation therapy, such as chemical ablation, radiofrequency ablation, cryoablation, and microwave ablation, has been shown to be clinically useful in many nonsurgical candidates. Ablation therapy has been used to treat both functioning adenomas and malignant tumors, including primary adrenal carcinoma and metastasis. For patients with functioning adenomas, biochemical and symptomatic improvement is achieved in 96 to 100% after ablation; for patients with malignant adrenal neoplasms, however, the survival benefit from ablation therapy remains unclear, though good initial results have been reported. This article outlines the current role of ablation therapy for adrenal lesions, as well as identifying some of the technical considerations for this procedure.

  2. Electron density measurement in gas discharge plasmas by optical and acoustic methods

    NASA Astrophysics Data System (ADS)

    Biagioni, A.; Anania, M. P.; Bellaveglia, M.; Chiadroni, E.; Cianchi, A.; Di Giovenale, D.; Di Pirro, G.; Ferrario, M.; Filippi, F.; Mostacci, A.; Pompili, R.; Shpakov, V.; Vaccarezza, C.; Villa, F.; Zigler, A.

    2016-08-01

    Plasma density represents a very important parameter for both laser wakefield and plasma wakefield acceleration, which use a gas-filled capillary plasma source. Several techniques can be used to measure the plasma density within a capillary discharge, which are mainly based on optical diagnostic methods, as for example the well-known spectroscopic method using the Stark broadening effect. In this work, we introduce a preliminary study on an alternative way to detect the plasma density, based on the shock waves produced by gas discharge in a capillary. Firstly, the measurements of the acoustic spectral content relative to the laser-induced plasmas by a solid target allowed us to understand the main properties of the acoustic waves produced during this kind of plasma generation; afterwards, we have extended such acoustic technique to the capillary plasma source in order to calibrate it by comparison with the stark broadening method.

  3. Microwave ablation of hepatocellular carcinoma

    PubMed Central

    Poggi, Guido; Tosoratti, Nevio; Montagna, Benedetta; Picchi, Chiara

    2015-01-01

    Although surgical resection is still the optimal treatment option for early-stage hepatocellular carcinoma (HCC) in patients with well compensated cirrhosis, thermal ablation techniques provide a valid non-surgical treatment alternative, thanks to their minimal invasiveness, excellent tolerability and safety profile, proven efficacy in local disease control, virtually unlimited repeatability and cost-effectiveness. Different energy sources are currently employed in clinics as physical agents for percutaneous or intra-surgical thermal ablation of HCC nodules. Among them, radiofrequency (RF) currents are the most used, while microwave ablations (MWA) are becoming increasingly popular. Starting from the 90s’, RF ablation (RFA) rapidly became the standard of care in ablation, especially in the treatment of small HCC nodules; however, RFA exhibits substantial performance limitations in the treatment of large lesions and/or tumors located near major heat sinks. MWA, first introduced in the Far Eastern clinical practice in the 80s’, showing promising results but also severe limitations in the controllability of the emitted field and in the high amount of power employed for the ablation of large tumors, resulting in a poor coagulative performance and a relatively high complication rate, nowadays shows better results both in terms of treatment controllability and of overall coagulative performance, thanks to the improvement of technology. In this review we provide an extensive and detailed overview of the key physical and technical aspects of MWA and of the currently available systems, and we want to discuss the most relevant published data on MWA treatments of HCC nodules in regard to clinical results and to the type and rate of complications, both in absolute terms and in comparison with RFA. PMID:26557950

  4. Surgical Ablation of Atrial Fibrillation.

    PubMed

    Ramlawi, Basel; Abu Saleh, Walid K

    2015-01-01

    The Cox-maze procedure for the restoration of normal sinus rhythm, initially developed by Dr. James Cox, underwent several iterations over the years. The main concept consists of creating a series of transmural lesions in the right and left atria that disrupt re-entrant circuits responsible for propagating the abnormal atrial fibrillation rhythm. The left atrial appendage is excluded as a component of the Maze procedure. For the first three iterations of the Cox- maze procedure, these lesions were performed using a surgical cut-and-sew approach that ensured transmurality. The Cox-Maze IV is the most currently accepted iteration. It achieves the same lesion set of the Cox- maze III but uses alternative energy sources to create the transmural lesions, potentially in a minimally invasive approach on the beating heart. High-frequency ultrasound, microwave, and laser energy have all been used with varying success in the past. Today, bipolar radiofrequency heat or cryotherapy cooling are the most accepted sources for creating linear lesions with consistent safety and transmurality. The robust and reliable nature of these energy delivery methods has yielded a success rate reaching 90% freedom from atrial fibrillation at 12 months. Such approaches offer a significant long-term advantage over catheter-based ablation, especially in patients having longstanding, persistent atrial fibrillation with characteristics such as dilated left atrial dimensions, poor ejection fraction, and failed catheter ablation. Based on these improved results, there currently is significant interest in developing a hybrid ablation strategy that incorporates the superior transmural robust lesions of surgical ablation, the reliable stroke prevention potential of epicardial left atrial appendage exclusion, and sophisticated mapping and confirmatory catheter-based ablation technology. Such a minimally invasive hybrid strategy for ablation may lead to the development of multidisciplinary "Afib teams" to

  5. A simulation-based and analytic analysis of the off-Hugoniot response of alternative inertial confinement fusion ablator materials

    NASA Astrophysics Data System (ADS)

    Moore, Alastair S.; Prisbrey, Shon; Baker, Kevin L.; Celliers, Peter M.; Fry, Jonathan; Dittrich, Thomas R.; Wu, Kuang-Jen J.; Kervin, Margaret L.; Schoff, Michael E.; Farrell, Mike; Nikroo, Abbas; Hurricane, Omar A.

    2016-09-01

    The attainment of self-propagating fusion burn in an inertial confinement target at the National Ignition Facility will require the use of an ablator with high rocket-efficiency and ablation pressure. The ablation material used during the National Ignition Campaign (Lindl et al. 2014) [1], a glow-discharge polymer (GDP), does not couple as efficiently as simulations indicated to the multiple-shock inducing radiation drive environment created by laser power profile (Robey et al., 2012). We investigate the performance of two other ablators, boron carbide (B4C) and high-density carbon (HDC) compared to the performance of GDP under the same hohlraum conditions. Ablation performance is determined through measurement of the shock speed produced in planar samples of the ablator material subjected to the identical multiple-shock inducing radiation drive environments that are similar to a generic three-shock ignition drive. Simulations are in better agreement with the off-Hugoniot performance of B4C than either HDC or GDP, and analytic estimations of the ablation pressure indicate that while the pressure produced by B4C and GDP is similar when the ablator is allowed to release, the pressure reached by B4C seems to exceed that of HDC when backed by a Au/quartz layer.

  6. Capillary electrophoresis for drug analysis

    NASA Astrophysics Data System (ADS)

    Lurie, Ira S.

    1999-02-01

    Capillary electrophoresis (CE) is a high resolution separation technique which is amenable to a wide variety of solutes, including compounds which are thermally degradable, non-volatile and highly polar, and is therefore well suited for drug analysis. Techniques which have been used in our laboratory include electrokinetic chromatography (ECC), free zone electrophoresis (CZE) and capillary electrochromatography (CEC). ECC, which uses a charged run buffer additive which migrates counter to osmotic flow, is excellent for many applications, including, drug screening and analyses of heroin, cocaine and methamphetamine samples. ECC approaches include the use of micelles and charged cyclodextrins, which allow for the separation of complex mixtures. Simultaneous separation of acidic, neutral and basic solutes and the resolution of optical isomers and positional isomers are possible. CZE has been used for the analysis of small ions (cations and anions) in heroin exhibits. For the ECC and CZE experiments performed in our laboratory, uncoated capillaries were used. In contrast, CEC uses capillaries packed with high performance liquid chromatography stationary phases, and offers both high peak capacities and unique selectivities. Applications include the analysis of cannabinoids and drug screening. Although CE suffers from limited concentration sensitivity, it is still applicable to trace analysis of drug samples, especially when using injection techniques such as stacking, or detection schemes such as laser induced fluorescence and extended pathlength UV.

  7. Bacterial motion in narrow capillaries

    PubMed Central

    Ping, Liyan; Wasnik, Vaibhav; Emberly, Eldon

    2014-01-01

    Motile bacteria often have to pass through small tortuous pores in soil or tissue of higher organisms. However, their motion in this prevalent type of niche is not fully understood. Here, we modeled it with narrow glass capillaries and identified a critical radius (Rc) for bacterial motion. Near the surface of capillaries narrower than that, the swimming trajectories are helices. In larger capillaries, they swim in distorted circles. Under non-slip condition, the peritrichous Escherichia coli swam in left-handed helices with an Rc of ∼10 μm near glass surface. However, slipping could occur in the fast monotrichous Pseudomonas fluorescens, when a speed threshold was exceeded, and thus both left-handed and right-handed helices were executed in glass capillaries. In the natural non-cylindrical pores, the near-surface trajectories would be spirals and twisted loops. Engaging in such motions reduces the bacterial migration rate. With a given pore size, the run length and the tumbling angle of the bacterium determine the probability and duration of their near-surface motion. Shear flow and chemotaxis potentially enhance it. Based on this observation, the puzzling previous observations on bacterial migration in porous environments can be interpreted. PMID:25764548

  8. Capillary Rise in a Wedge

    ERIC Educational Resources Information Center

    Piva, M.

    2009-01-01

    In introductory-level physics courses, the concept of surface tension is often illustrated using the example of capillary rise in thin tubes. In this paper the author describes experiments conducted using a planar geometry created with two small plates forming a thin wedge. The distribution of the fluid entering the wedge can be studied as a…

  9. Laser ablation based fuel ignition

    DOEpatents

    Early, James W.; Lester, Charles S.

    1998-01-01

    There is provided a method of fuel/oxidizer ignition comprising: (a) application of laser light to a material surface which is absorptive to the laser radiation; (b) heating of the material surface with the laser light to produce a high temperature ablation plume which emanates from the heated surface as an intensely hot cloud of vaporized surface material; and (c) contacting the fuel/oxidizer mixture with the hot ablation cloud at or near the surface of the material in order to heat the fuel to a temperature sufficient to initiate fuel ignition.

  10. Laser ablation based fuel ignition

    DOEpatents

    Early, J.W.; Lester, C.S.

    1998-06-23

    There is provided a method of fuel/oxidizer ignition comprising: (a) application of laser light to a material surface which is absorptive to the laser radiation; (b) heating of the material surface with the laser light to produce a high temperature ablation plume which emanates from the heated surface as an intensely hot cloud of vaporized surface material; and (c) contacting the fuel/oxidizer mixture with the hot ablation cloud at or near the surface of the material in order to heat the fuel to a temperature sufficient to initiate fuel ignition. 3 figs.

  11. Transhemangioma Ablation of Hepatocellular Carcinoma

    SciTech Connect

    Pua, Uei

    2012-12-15

    Radiofrequency ablation (RFA) is a well-established treatment modality in the treatment of early hepatocellular carcinoma (HCC) [1]. Safe trajectory of the RFA probe is crucial in decreasing collateral tissue damage and unwarranted probe transgression. As a percutaneous technique, however, the trajectory of the needle is sometimes constrained by the available imaging plane. The presence of a hemangioma beside an HCC is uncommon but poses the question of safety related to probe transgression. We hereby describe a case of transhemangioma ablation of a dome HCC.

  12. Angioplasty and stent placement - peripheral arteries - discharge

    MedlinePlus

    Percutaneous transluminal angioplasty - peripheral artery - discharge; PTA - peripheral artery - discharge; Angioplasty - peripheral artery - discharge; Balloon angioplasty - peripheral artery- discharge; PAD - PTA discharge; PVD - PTA discharge

  13. Fractional ablative laser skin resurfacing: a review.

    PubMed

    Tajirian, Ani L; Tarijian, Ani L; Goldberg, David J

    2011-12-01

    Ablative laser technology has been in use for many years now. The large side effect profile however has limited its use. Fractional ablative technology is a newer development which combines a lesser side effect profile along with similar efficacy. In this paper we review fractional ablative laser skin resurfacing.

  14. Capillary-Inertial Colloidal Catapult upon Drop Coalescence

    NASA Astrophysics Data System (ADS)

    Chavez, Roger; Liu, Fangjie; Feng, James; Chen, Chuan-Hua

    2014-11-01

    To discharge micron-sized particles such as colloidal contaminants and biological spores, an enormous power density is needed to compete against the strong adhesive forces between the small particles and the supporting surface as well as the significant air friction exerted on the particles. Here, we demonstrate a colloidal catapult that achieves such a high power density by extracting surface energy released upon drop coalescence within an extremely short time period, which is governed by the capillary-inertial process converting the released surface energy into the bulk inertia of the merged drop. When two drops coalesce on top of a spherical particle, the resulting capillary-inertial oscillation is perturbed by the solid particle, giving rise to a net momentum eventually propelling the particle to launch from the supporting surface. The measured launching velocity follows a scaling law that accounts for the redistribution of the momentum of the merged drop onto the particle-drop complex, and is therefore proportional to the capillary-inertial velocity characterizing the coalescing drops. The interfacial flow process associated with the colloidal catapult is elucidated with both high-speed imaging and phase-field simulations.

  15. Microwave discharge in a finite length vessel

    NASA Astrophysics Data System (ADS)

    Kiss'ovski, Zh; Vachkov, V.; Iordanova, S.; Koleva, I.

    2012-03-01

    A microwave surface-wave discharge at low pressure in a finite length vessel is experimentally investigated. Argon plasma is created in a dielectric capillary with length of 15 mm, the tube being an extension of an open-ended coaxial structure. Microwave power at frequency 2.45 GHz is coupled into the source applicator at power levels 6-15 W. The plasma column increases with the power applied and standing wave mode is realized when its length is equal to the capillary length. The electron temperature and plasma density are obtained simultaneously by passive optical emission spectroscopy using the line-ratio method. The surface waves phase-diagram shows that their wavelengths are much lower than the free-space wavelength. The input impedance of the plasma column - modelled as a lossy transmission line - has resonance behaviour when its length is equal to λg/2 or λg (λg being the surface waves wavelength). The results obtained for the plasma parameters, the surface waves wavelength and the vessel length show correlation to the power reflected, absorbed and radiated from the plasma column. The radiation pattern of the column shows that the main lobe is nearly perpendicular to the capillary axis.

  16. Modern Advances in Ablative TPS

    NASA Technical Reports Server (NTRS)

    Venkatapathy, Ethiraj

    2013-01-01

    Topics covered include: Physics of Hypersonic Flow and TPS Considerations. Destinations, Missions and Requirements. State of the Art Thermal Protection Systems Capabilities. Modern Advances in Ablative TPS. Entry Systems Concepts. Flexible TPS for Hypersonic Inflatable Aerodynamic Decelerators. Conformal TPS for Rigid Aeroshell. 3-D Woven TPS for Extreme Entry Environment. Multi-functional Carbon Fabric for Mechanically Deployable.

  17. Surface Modification of ICF Target Capsules by Pulsed Laser Ablation

    SciTech Connect

    Carlson, Lane C.; Johnson, Michael A.; Bunn, Thomas L.

    2016-06-30

    Topographical modifications of spherical surfaces are imprinted on National Ignition Facility (NIF) target capsules by extending the capabilities of a recently developed full surface (4π) laser ablation and mapping apparatus. The laser ablation method combines the precision, energy density and long reach of a focused laser beam to pre-impose sinusoidal modulations on the outside surface of High Density Carbon (HDC) capsules and the inside surface of Glow Discharge Polymer (GDP) capsules. Sinusoidal modulations described in this paper have sub-micron to 10’s of microns vertical scale and wavelengths as small as 30 μm and as large as 200 μm. The modulated patterns are created by rastering a focused laser fired at discrete capsule surface locations for a specified number of pulses. The computer program developed to create these raster patterns uses inputs such as laser beam intensity profile, the material removal function, the starting surface figure and the desired surface figure. The patterns are optimized to minimize surface roughness. Lastly, in this paper, simulated surfaces are compared with actual ablated surfaces measured using confocal microscopy.

  18. Surface Modification of ICF Target Capsules by Pulsed Laser Ablation

    DOE PAGES

    Carlson, Lane C.; Johnson, Michael A.; Bunn, Thomas L.

    2016-06-30

    Topographical modifications of spherical surfaces are imprinted on National Ignition Facility (NIF) target capsules by extending the capabilities of a recently developed full surface (4π) laser ablation and mapping apparatus. The laser ablation method combines the precision, energy density and long reach of a focused laser beam to pre-impose sinusoidal modulations on the outside surface of High Density Carbon (HDC) capsules and the inside surface of Glow Discharge Polymer (GDP) capsules. Sinusoidal modulations described in this paper have sub-micron to 10’s of microns vertical scale and wavelengths as small as 30 μm and as large as 200 μm. The modulatedmore » patterns are created by rastering a focused laser fired at discrete capsule surface locations for a specified number of pulses. The computer program developed to create these raster patterns uses inputs such as laser beam intensity profile, the material removal function, the starting surface figure and the desired surface figure. The patterns are optimized to minimize surface roughness. Lastly, in this paper, simulated surfaces are compared with actual ablated surfaces measured using confocal microscopy.« less

  19. Vessel Sewage Discharges

    EPA Pesticide Factsheets

    Vessel sewage discharges are regulated under Section 312 of the Clean Water Act, which is jointly implemented by the EPA and Coast Guard. This homepage links to information on marine sanitation devices and no discharge zones.

  20. Electrode configuration for extreme-UV electrical discharge source

    DOEpatents

    Spence, Paul Andrew; Fornaciari, Neal Robert; Chang, Jim Jihchyun

    2002-01-01

    It has been demonstrated that debris generation within an electric capillary discharge source, for generating extreme ultraviolet and soft x-ray, is dependent on the magnitude and profile of the electric field that is established along the surfaces of the electrodes. An electrode shape that results in uniform electric field strength along its surface has been developed to minimize sputtering and debris generation. The electric discharge plasma source includes: (a) a body that defines a circular capillary bore that has a proximal end and a distal end; (b) a back electrode positioned around and adjacent to the distal end of the capillary bore wherein the back electrode has a channel that is in communication with the distal end and that is defined by a non-uniform inner surface which exhibits a first region which is convex, a second region which is concave, and a third region which is convex wherein the regions are viewed outwardly from the inner surface of the channel that is adjacent the distal end of the capillary bore so that the first region is closest to the distal end; (c) a front electrode positioned around and adjacent to the proximal end of the capillary bore wherein the front electrode has an opening that is communication with the proximal end and that is defined by a non-uniform inner surface which exhibits a first region which is convex, a second region which is substantially linear, and third region which is convex wherein the regions are viewed outwardly from the inner surface of the opening that is adjacent the proximal end of the capillary bore so that the first region is closest to the proximal end; and (d) a source of electric potential that is connected across the front and back electrodes.

  1. Pediatric heart surgery - discharge

    MedlinePlus

    ... get enough calories to heal and grow. After heart surgery, most babies and infants (younger than 12 to 15 months) can take ... valve surgery - children - discharge; Heart surgery - pediatric - discharge; Heart transplant - pediatric - discharge ... open heart surgery References Bernstein D. General principles ...

  2. Spine surgery - discharge

    MedlinePlus

    ... symptoms should get better in a few weeks. Recovery after laminectomy and fusion surgery is longer. You will not be able ... discharge; Anterior spinal fusion - discharge; Spine surgery - spinal fusion - discharge Images Spinal surgery -- cervical - series References Agrawal BM, Zeidman SM, Rhines L, ...

  3. Esophageal papilloma: Flexible endoscopic ablation by radiofrequency

    PubMed Central

    del Genio, Gianmattia; del Genio, Federica; Schettino, Pietro; Limongelli, Paolo; Tolone, Salvatore; Brusciano, Luigi; Avellino, Manuela; Vitiello, Chiara; Docimo, Giovanni; Pezzullo, Angelo; Docimo, Ludovico

    2015-01-01

    Squamous papilloma of the esophagus is a rare benign lesion of the esophagus. Radiofrequency ablation is an established endoscopic technique for the eradication of Barrett esophagus. No cases of endoscopic ablation of esophageal papilloma by radiofrequency ablation (RFA) have been reported. We report a case of esophageal papilloma successfully treated with a single session of radiofrequency ablation. Endoscopic ablation of the lesion was achieved by radiofrequency using a new catheter inserted through the working channel of endoscope. The esophageal ablated tissue was removed by a specifically designed cup. Complete ablation was confirmed at 3 mo by endoscopy with biopsies. This case supports feasibility and safety of as a new potential indication for BarrxTM RFA in patients with esophageal papilloma. PMID:25789102

  4. Percutaneous ablation of benign bone tumors.

    PubMed

    Welch, Brian T; Welch, Timothy J

    2011-09-01

    Percutaneous image-guided ablation has become a standard of practice and one of the primary modalities for treatment of benign bone tumors. Ablation is most commonly used to treat osteoid osteomas but may also be used in the treatment of chondroblastomas, osteoblastomas, and giant cell tumors. Percutaneous image-guided ablation of benign bone tumors carries a high success rate (>90% in case series) and results in decreased morbidity, mortality, and expense compared with traditional surgical methods. The ablation technique most often applied to benign bone lesions is radiofrequency ablation. Because the ablation technique has been extensively applied to osteoid osteomas and because of the uncommon nature of other benign bone tumors, we will primarily focus this discussion on the percutaneous ablation of osteoid osteomas.

  5. Capillary rise in cellulose sponges

    NASA Astrophysics Data System (ADS)

    Kim, Jungchul; Kim, Ho-Young; Mahadevan, L.

    2011-11-01

    A cellulose sponge, commonly used for clean-up jobs, can absorb and hold a significant amount of water within its pores, whose size ranges from micrometers to millimeters. We investigate the dynamics of capillary rise of water in the sponge using a combination of experiment and theory. We find that the rate of the capillary rise is significantly lower than Washburn's rule that assumes the sponge as a row of adjoined pores and the liquid flow to be driven by the Laplace pressure. We introduce a novel theory to model the flow in the hygroscopic porous media by combining Darcy's law based on the moisture concentration and the modified Young-Laplace equation. The scaling law constructed through this work agrees well with the experimental results.

  6. Step-gradient capillary electrochromatography.

    PubMed

    Euerby, M R; Gilligan, D; Johnson, C M; Bartle, K D

    1997-10-01

    The analytical benefits of using a step-gradient in capillary electrochromatography (CEC) are demonstrated. The application of step-gradient CEC to the analysis of six diuretics of widely differing lipophilicities was evaluated and shown to result in a marked reduction in the analysis time and an improvement in the peak shape for later-eluting lipophilic components. When the step-gradient approach was performed in an automated mode, the retention time RSD for repeated injections was below 1%.

  7. Capillary electrophoresis systems and methods

    DOEpatents

    Dorairaj, Rathissh; Keynton, Robert S.; Roussel, Thomas J.; Crain, Mark M.; Jackson, Douglas J.; Walsh, Kevin M.; Naber, John F.; Baldwin, Richard P.; Franco, Danielle B.

    2011-08-02

    An embodiment of the invention is directed to a capillary electrophoresis apparatus comprising a plurality of separation micro-channels. A sample loading channel communicates with each of the plurality of separation channels. A driver circuit comprising a plurality of electrodes is configured to induce an electric field across each of the plurality of separation channels sufficient to cause analytes in the samples to migrate along each of the channels. The system further comprises a plurality of detectors configured to detect the analytes.

  8. Anti-reflux surgery - children - discharge

    MedlinePlus

    Fundoplication - children - discharge; Nissen fundoplication - children - discharge; Belsey (Mark IV) fundoplication - children - discharge; Toupet fundoplication - children - discharge; Thal fundoplication - ...

  9. Microwave Ablation Compared with Radiofrequency Ablation for Breast Tissue in an Ex Vivo Bovine Udder Model

    SciTech Connect

    Tanaka, Toshihiro; Westphal, Saskia; Isfort, Peter; Braunschweig, Till; Penzkofer, Tobias Bruners, Philipp; Kichikawa, Kimihiko; Schmitz-Rode, Thomas Mahnken, Andreas H.

    2012-08-15

    Purpose: To compare the effectiveness of microwave (MW) ablation with radiofrequency (RF) ablation for treating breast tissue in a nonperfused ex vivo model of healthy bovine udder tissue. Materials and Methods: MW ablations were performed at power outputs of 25W, 35W, and 45W using a 915-MHz frequency generator and a 2-cm active tip antenna. RF ablations were performed with a bipolar RF system with 2- and 3-cm active tip electrodes. Tissue temperatures were continuously monitored during ablation. Results: The mean short-axis diameters of the coagulation zones were 1.34 {+-} 0.14, 1.45 {+-} 0.13, and 1.74 {+-} 0.11 cm for MW ablation at outputs of 25W, 35W, and 45W. For RF ablation, the corresponding values were 1.16 {+-} 0.09 and 1.26 {+-} 0.14 cm with electrodes having 2- and 3-cm active tips, respectively. The mean coagulation volumes were 2.27 {+-} 0.65, 2.85 {+-} 0.72, and 4.45 {+-} 0.47 cm{sup 3} for MW ablation at outputs of 25W, 35W, and 45W and 1.18 {+-} 0.30 and 2.29 {+-} 0.55 cm{sup 3} got RF ablation with 2- and 3-cm electrodes, respectively. MW ablations at 35W and 45W achieved significantly longer short-axis diameters than RF ablations (P < 0.05). The highest tissue temperature was achieved with MW ablation at 45W (P < 0.05). On histological examination, the extent of the ablation zone in MW ablations was less affected by tissue heterogeneity than that in RF ablations. Conclusion: MW ablation appears to be advantageous with respect to the volume of ablation and the shape of the margin of necrosis compared with RF ablation in an ex vivo bovine udder.

  10. Capillary Electrophoresis - Optical Detection Systems

    SciTech Connect

    Sepaniak, M. J.

    2001-08-06

    Molecular recognition systems are developed via molecular modeling and synthesis to enhance separation performance in capillary electrophoresis and optical detection methods for capillary electrophoresis. The underpinning theme of our work is the rational design and development of molecular recognition systems in chemical separations and analysis. There have been, however, some subtle and exciting shifts in our research paradigm during this period. Specifically, we have moved from mostly separations research to a good balance between separations and spectroscopic detection for separations. This shift is based on our perception that the pressing research challenges and needs in capillary electrophoresis and electrokinetic chromatography relate to the persistent detection and flow rate reproducibility limitations of these techniques (see page 1 of the accompanying Renewal Application for further discussion). In most of our work molecular recognition reagents are employed to provide selectivity and enhance performance. Also, an emerging trend is the use of these reagents with specially-prepared nano-scale materials. Although not part of our DOE BES-supported work, the modeling and synthesis of new receptors has indirectly supported the development of novel microcantilevers-based MEMS for the sensing of vapor and liquid phase analytes. This fortuitous overlap is briefly covered in this report. Several of the more significant publications that have resulted from our work are appended. To facilitate brevity we refer to these publications liberally in this progress report. Reference is also made to very recent work in the Background and Preliminary Studies Section of the Renewal Application.

  11. Capillary stretching of elastic fibers

    NASA Astrophysics Data System (ADS)

    Protiere, Suzie; Stone, Howard A.; Duprat, Camille

    2014-11-01

    Fibrous media consisting of constrained flexible fibers can be found in many engineered systems (membranes in filters, woven textile, matted paper). When such materials interact with a liquid, the presence of liquid/air interfaces induces capillary forces that deform the fibers. To model this interaction we study the behaviour of a finite volume of liquid deposited on two parallel flexible fibers clamped at both ends. A tension along the fibers is imposed and may be varied. We show that the system undergoes various morphological changes as the interfiber distance, the elasticity and the tension of the fibers are varied. For a certain range of parameters, the liquid spreads along the fibers and pulls them together, leading to the ``zipping'' of the fibers. This capillary adhesion can then be enhanced or reduced by changing the tension within the fibers. We will show that balancing stretching and capillary forces allows the prediction of this transition as well as the conditions for which detachment of the fibers occurs. These results may be used to prevent the clogging of fibrous membranes or to optimize the capture of liquids.

  12. Progression of Diabetic Capillary Occlusion: A Model

    PubMed Central

    Gens, John Scott; Glazier, James A.; Burns, Stephen A.; Gast, Thomas J.

    2016-01-01

    An explanatory computational model is developed of the contiguous areas of retinal capillary loss which play a large role in diabetic maculapathy and diabetic retinal neovascularization. Strictly random leukocyte mediated capillary occlusion cannot explain the occurrence of large contiguous areas of retinal ischemia. Therefore occlusion of an individual capillary must increase the probability of occlusion of surrounding capillaries. A retinal perifoveal vascular sector as well as a peripheral retinal capillary network and a deleted hexagonal capillary network are modelled using Compucell3D. The perifoveal modelling produces a pattern of spreading capillary loss with associated macular edema. In the peripheral network, spreading ischemia results from the progressive loss of the ladder capillaries which connect peripheral arterioles and venules. System blood flow was elevated in the macular model before a later reduction in flow in cases with progression of capillary occlusions. Simulations differing only in initial vascular network structures but with identical dynamics for oxygen, growth factors and vascular occlusions, replicate key clinical observations of ischemia and macular edema in the posterior pole and ischemia in the retinal periphery. The simulation results also seem consistent with quantitative data on macular blood flow and qualitative data on venous oxygenation. One computational model applied to distinct capillary networks in different retinal regions yielded results comparable to clinical observations in those regions. PMID:27300722

  13. Fluid Delivery System For Capillary Electrophoretic Applications.

    SciTech Connect

    Li, Qingbo; Liu, Changsheng; Kane, Thomas E.; Kernan, John R.; Sonnenschein, Bernard; Sharer, Michael V.

    2002-04-23

    An automated electrophoretic system is disclosed. The system employs a capillary cartridge having a plurality of capillary tubes. The cartridge has a first array of capillary ends projecting from one side of a plate. The first array of capillary ends are spaced apart in substantially the same manner as the wells of a microtitre tray of standard size. This allows one to simultaneously perform capillary electrophoresis on samples present in each of the wells of the tray. The system includes a stacked, dual carrousel arrangement to eliminate cross-contamination resulting from reuse of the same buffer tray on consecutive executions from electrophoresis. The system also has a gel delivery module containing a gel syringe/a stepper motor or a high pressure chamber with a pump to quickly and uniformly deliver gel through the capillary tubes. The system further includes a multi-wavelength beam generator to generate a laser beam which produces a beam with a wide range of wavelengths. An off-line capillary reconditioner thoroughly cleans a capillary cartridge to enable simultaneous execution of electrophoresis with another capillary cartridge. The streamlined nature of the off-line capillary reconditioner offers the advantage of increased system throughput with a minimal increase in system cost.

  14. Underwater plasma discharge and its water treatment applications

    NASA Astrophysics Data System (ADS)

    Ma, Sukhwal; Huh, Jin Young; Kim, Kangil; Hong, Yong Cheol; National Fusion Research Institute Team; Chonbuk National University Team; Kwangwoon University Team; NPAC Team

    2016-09-01

    In recent, the quality of water has been exacerbated by the influx of wastewater and water pollutants. There have been frequent occurrences of water blooms due to the eutrophication of river. Therefore, the needs for water treatment are increased through effective and environment-friendly method. In this work, we propose the plasma system to overcome the problems mentioned above using underwater discharge plasma. The underwater discharges are generated by capillary electrode, and have the advantages of low cost, high efficiency and eco-friendly processing. The proposed technologies can be suitable for eliminating cyanobacteria, decreasing the concentration of oil dissolved in water, and purifying wastewater. Cyanobacteria is killed directly by the underwater discharge and water-dissolved oil and heavy-metal wastewater are purified by coagulation effect, which may result from the chemical reactions of underwater plasma. Consequently, these technologies using underwater discharge can be alternative methods to replace the existing technologies.

  15. Nonsputtering impulse magnetron discharge

    SciTech Connect

    Khodachenko, G. V.; Mozgrin, D. V.; Fetisov, I. K.; Stepanova, T. V.

    2012-01-15

    Experiments with quasi-steady high-current discharges in crossed E Multiplication-Sign B fields in various gases (Ar, N{sub 2}, H{sub 2}, and SF{sub 6}) and gas mixtures (Ar/SF{sub 6} and Ar/O{sub 2}) at pressures from 10{sup -3} to 5 Torr in discharge systems with different configurations of electric and magnetic fields revealed a specific type of stable low-voltage discharge that does not transform into an arc. This type of discharge came to be known as a high-current diffuse discharge and, later, a nonsputtering impulse magnetron discharge. This paper presents results from experimental studies of the plasma parameters (the electron temperature, the plasma density, and the temperature of ions and atoms of the plasma-forming gas) of a high-current low-pressure diffuse discharge in crossed E Multiplication-Sign B fields.

  16. Quantifying the cleanliness of glass capillaries.

    PubMed

    Bowman, C L

    1998-01-01

    I used capillary rise methods to investigate the lumenal surface properties of quartz (fused silica, Amersil T-08), borosilicate (Corning 7800), and high-lead glass (Corning 0010) capillaries commonly used to make patch pipets. I calculated the capillary rise and contact angle for water and methanol from weight measurements. The capillary rise was compared with the theoretical maximum value calculated by assuming each fluid perfectly wetted the lumenal surface of the glass (i.e., zero contact angle, which reflects the absence of surface contamination). For borosilicate, high-lead, and quartz capillaries, the rise for water was substantially less than the theoretical maximum rise. Exposure of the borosilicate, lead, and quartz capillaries to several cleaning methods resulted in substantially better--but not perfect--agreement between the theoretical maximum rise and calculated capillary rise. By contrast, the capillary rise for methanol was almost identical in untreated and cleaned capillaries, but less than its theoretical maximum rise. The residual discrepancy between the observed and theoretical rise for water could not be improved on by trying a variety of cleaning procedures, but some cleaning methods were superior to others. The water solubility of the surface contaminants, deduced from the effectiveness of repeated rinsing, was different for each of the three types of capillaries examined: Corning 7800 > quartz > Corning 0010. A surface film was also detected in quatz tubing with an internal filament. I conclude that these borosilicate, quartz, and high-lead glass capillaries have a film on the lumenal surface, which can be removed using appropriate cleaning methods. The surface contaminants may be unique to each type of capillary and may also be hydrophobic. Two simple methods are presented to quantitate the cleanliness of glass capillary tubing commonly used to make pipets for studies of biological membranes. It is not known if the surface film is of

  17. Ablation of benign prostatic hyperplasia using microbubble-mediated ultrasound cavitation.

    PubMed

    Li, Tao; Liu, Zheng

    2010-04-01

    Benign prostatic hyperplasia (BPH) is a world-wide common disease in elderly male patients. A number of invasive physiotherapies have been used to replace prostatectomy. In this article we report our hypothesis of using microbubbles-mediated ultrasound cavitation effects to ablate prostatic tissues. Microbubble ultrasound contrast agent is widely used contrast media in ultrasonography, yet it is also found to act as cavitation nuclei or enhancer. Once excited by a high peak pressure ultrasound pulse, the mechanical effects, like shock wave and microstream, released from cavitation could produce a series of bioeffects, contributing to sonoporation, microvascular rupture and hematoma. BPH is known to have hyperplastic neovasculature and this make it possible to be disrupted by the physical effects of cavitation under existing microbubbles in circulation. Mechanical ablation of prostatic capillary or small vessels could result in pathological alterations such as thrombosis, micro-circulation blockage, prostatic necrosis and atrophia. Thereupon it could effectively treat BPH by nontraumatic ways.

  18. Investigation of a Gallium MPD Thruster with an Ablating Cathode

    NASA Technical Reports Server (NTRS)

    Thomas, Robert E.; Burton, Rodney L.; Polzin, Kurt A.

    2010-01-01

    Arc impedance, exhaust velocity, and plasma probe measurements are presented. The thruster is driven by a 50 microsecond pulse from a 6.2 milliohm pulse forming network, and gallium is supplied to the discharge by evaporation of the cathode. The arc voltage is found to vary linearly with the discharge current with an arc impedance of 6.5 milliohms. Electrostatic probes yield an exhaust velocity that is invariant with the discharge current and has a peak value of 20 kilometers per second, which is in reasonable agreement with the value (16 plus or minus 1 kilometer per second) calculated from the mass bit and discharge current data. Triple probe measurements yield on axis electron temperatures in the range of 0.8-3.8 eV, electron densities in the range of 1.6 x 10(exp 21) to 2.1 x 10(exp 22) per cubic meter, and a divergence half angle of 16 degrees. Measurements within the interelectrode region yield a peak magnetic field of 0.8 T, and the observed radial trends are consistent with an azimuthally symmetric current distribution. A cathode power balance model is coupled with an ablative heat conduction model predicting mass bit values that are within 20% of the experimental values.

  19. Cholecystokinin-Assisted Hydrodissection of the Gallbladder Fossa during FDG PET/CT-guided Liver Ablation

    SciTech Connect

    Tewari, Sanjit O.; Petre, Elena N.; Osborne, Joseph; Sofocleous, Constantinos T.

    2013-12-15

    A 68-year-old female with colorectal cancer developed a metachronous isolated fluorodeoxyglucose-avid (FDG-avid) segment 5/6 gallbladder fossa hepatic lesion and was referred for percutaneous ablation. Pre-procedure computed tomography (CT) images demonstrated a distended gallbladder abutting the segment 5/6 hepatic metastasis. In order to perform ablation with clear margins and avoid direct puncture and aspiration of the gallbladder, cholecystokinin was administered intravenously to stimulate gallbladder contraction before hydrodissection. Subsequently, the lesion was ablated successfully with sufficient margins, of greater than 1.0 cm, using microwave with ultrasound and FDG PET/CT guidance. The patient tolerated the procedure very well and was discharged home the next day.

  20. Characterization of tracked radiofrequency ablation in phantom

    SciTech Connect

    Chen, Chun-Cheng R.; Miga, Michael I.; Galloway, Robert L.

    2007-10-15

    In radiofrequency ablation (RFA), successful therapy requires accurate, image-guided placement of the ablation device in a location selected by a predictive treatment plan. Current planning methods rely on geometric models of ablations that are not sensitive to underlying physical processes in RFA. Implementing plans based on computational models of RFA with image-guided techniques, however, has not been well characterized. To study the use of computational models of RFA in planning needle placement, this work compared ablations performed with an optically tracked RFA device with corresponding models of the ablations. The calibration of the tracked device allowed the positions of distal features of the device, particularly the tips of the needle electrodes, to be determined to within 1.4{+-}0.6 mm of uncertainty. Ablations were then performed using the tracked device in a phantom system based on an agarose-albumin mixture. Images of the sliced phantom obtained from the ablation experiments were then compared with the predictions of a bioheat transfer model of RFA, which used the positional data of the tracked device obtained during ablation. The model was demonstrated to predict 90% of imaged pixels classified as being ablated. The discrepancies between model predictions and observations were analyzed and attributed to needle tracking inaccuracy as well as to uncertainties in model parameters. The results suggest the feasibility of using finite element modeling to plan ablations with predictable outcomes when implemented using tracked RFA.

  1. Artificial meteor ablation studies: Olivine

    NASA Technical Reports Server (NTRS)

    Blanchard, M. B.; Cunningham, G. G.

    1973-01-01

    Artificial meteor ablation was performed on a Mg-rich olivine sample using an arc-heated plasma of ionized air. Experimental conditions simulated a meteor traveling about 12 km/sec at an altitude of 70 km. The mineral content of the original olivine sample was 98% olivine (including traces of olivine alteration products) and 2% chromite. Forsterite content of the original olivine was Fo-89. After ablation, the forsterite content had increased to Fo-94 in the recrystallized olivine. In addition, lamella-like intergrowths of magnetite were prevalent constituents. Wherever magnetite occurred, there was an increase in Mg and a corresponding decrease in Fe for the recrystallized olivine. The Allende fusion crust consisted of a recrystallized olivine, which was more Mg-rich and Fe-deficient than the original meteorite's olivine, and abundant magnetite grains. Although troilite and pentlandite were the common opaque mineral constituents in this meteorite, magnetite was the principal opaque mineral found in the fusion crust.

  2. Laser Ablation for Medical Applications

    NASA Astrophysics Data System (ADS)

    Hayashi, Ken-Ichi

    Medical applications of laser are measurement, laser surgery, in-situ monitoring, and processing of medical devices. In this paper, author briefly reviews the trends of medical applications, describes some new applications, and then discuss about the future trends and problems of medical applications. At present, the domestic market of laser equipment for medical applications is nearly 1/10 of that for industrial applications, which has registered significant growth continuously. Laser surgery as a minimum invasive surgery under arthroscope is expected to decrease the pain of patients. Precise processing such as cutting and welding is suitable for manufacturing medical devices. Pulsed laser deposition has been successfully applied to the thin film coating. The corneal refractive surgery by ArF excimer laser has been widely accepted for its highly safe operation. Laser ablation for retinal implant in the visual prosthesis is one of the promising applications of laser ablation in medicine. New applications with femtosecond laser are expected in the near future.

  3. Percutaneous ablation of pancreatic cancer

    PubMed Central

    D’Onofrio, Mirko; Ciaravino, Valentina; De Robertis, Riccardo; Barbi, Emilio; Salvia, Roberto; Girelli, Roberto; Paiella, Salvatore; Gasparini, Camilla; Cardobi, Nicolò; Bassi, Claudio

    2016-01-01

    Pancreatic ductal adenocarcinoma is a highly aggressive tumor with an overall 5-year survival rate of less than 5%. Prognosis and treatment depend on whether the tumor is resectable or not, which mostly depends on how quickly the diagnosis is made. Chemotherapy and radiotherapy can be both used in cases of non-resectable pancreatic cancer. In cases of pancreatic neoplasm that is locally advanced, non-resectable, but non-metastatic, it is possible to apply percutaneous treatments that are able to induce tumor cytoreduction. The aim of this article will be to describe the multiple currently available treatment techniques (radiofrequency ablation, microwave ablation, cryoablation, and irreversible electroporation), their results, and their possible complications, with the aid of a literature review. PMID:27956791

  4. Laser Ablation Molecular Isotopic Spectrometry

    NASA Astrophysics Data System (ADS)

    Russo, Richard E.; Bol'shakov, Alexander A.; Mao, Xianglei; McKay, Christopher P.; Perry, Dale L.; Sorkhabi, Osman

    2011-02-01

    A new method of performing optical isotopic analysis of condensed samples in ambient air and at ambient pressure has been developed: Laser Ablation Molecular Isotopic Spectrometry (LAMIS). The technique uses radiative transitions from molecular species either directly vaporized from a sample or formed by associative mechanisms of atoms or ions in a laser ablation plume. This method is an advanced modification of a known atomic emission technique called laser-induced breakdown spectroscopy (LIBS). The new method — LAMIS — can determine not only chemical composition but also isotopic ratios of elements in the sample. Isotopic measurements are enabled by significantly larger isotopic shifts found in molecular spectra relative to atomic spectra. Analysis can be performed from a distance and in real time. No sample preparation or pre-treatment is required. Detection of the isotopes of hydrogen, boron, carbon, and oxygen are discussed to illustrate the technique.

  5. Percutaneous ablation of pancreatic cancer.

    PubMed

    D'Onofrio, Mirko; Ciaravino, Valentina; De Robertis, Riccardo; Barbi, Emilio; Salvia, Roberto; Girelli, Roberto; Paiella, Salvatore; Gasparini, Camilla; Cardobi, Nicolò; Bassi, Claudio

    2016-11-28

    Pancreatic ductal adenocarcinoma is a highly aggressive tumor with an overall 5-year survival rate of less than 5%. Prognosis and treatment depend on whether the tumor is resectable or not, which mostly depends on how quickly the diagnosis is made. Chemotherapy and radiotherapy can be both used in cases of non-resectable pancreatic cancer. In cases of pancreatic neoplasm that is locally advanced, non-resectable, but non-metastatic, it is possible to apply percutaneous treatments that are able to induce tumor cytoreduction. The aim of this article will be to describe the multiple currently available treatment techniques (radiofrequency ablation, microwave ablation, cryoablation, and irreversible electroporation), their results, and their possible complications, with the aid of a literature review.

  6. Joule heating in packed capillaries used in capillary electrochromatography.

    PubMed

    Rathore, Anurag S; Reynolds, Kimberly J; Colón, Luis A

    2002-09-01

    Effective heat dissipation is critical for reproducible and efficient separations in electrically driven separation systems. Flow rate, retention kinetics, and analyte diffusion rates are some of the characteristics that are affected by variation in the temperature of the mobile phase inside the column. In this study, we examine the issue of Joule heating in packed capillary columns used in capillary electrochromatography (CEC). As almost all commonly used CEC packings are poor thermal conductors, it is assumed that the packing particles do not conduct heat and heat transfer is solely through the mobile phase flowing through the system. The electrical conductivity of various mobile phases was measured at different temperatures by a conductivity meter and the temperature coefficient for each mobile phase was calculated. This was followed by measurement of the electrical current at several applied voltages to calculate the conductivity of the solution within the column as a function of the applied voltage. An overall increase in the conductivity is attributed to Joule heating within the column, while a constant conductivity means good heat dissipation. A plot of conductivity versus applied voltage was used as the indicator of poor heat dissipation. Using theories that have been proposed earlier for modeling of Joule heating effects in capillary electrophoresis (CE), we estimated the temperature within CEC columns. Under mobile and stationary phase conditions typically used in CEC, heat dissipation was found to be not always efficient. Elevated temperatures within the columns in excess of 23 degrees C above ambient temperature were calculated for packed columns, and about 35 degrees C for an open column, under a given set of conditions. The results agree with recently published experimental findings with nuclear magnetic resonance (NMR) thermometry, and Raman spectroscopic measurements.

  7. Microfluidic PMMA interfaces for rectangular glass capillaries

    NASA Astrophysics Data System (ADS)

    Evander, Mikael; Tenje, Maria

    2014-02-01

    We present the design and fabrication of a polymeric capillary fluidic interface fabricated by micro-milling. The design enables the use of glass capillaries with any kind of cross-section in complex microfluidic setups. We demonstrate two different designs of the interface; a double-inlet interface for hydrodynamic focusing and a capillary interface with integrated pneumatic valves. Both capillary interfaces are presented together with examples of practical applications. This communication shows the design optimization and presents details of the fabrication process. The capillary interface opens up for the use of complex microfluidic systems in single-use glass capillaries. They also enable simple fabrication of glass/polymer hybrid devices that can be beneficial in many research fields where a pure polymer chip negatively affects the device's performance, e.g. acoustofluidics.

  8. Capillary pumped loop body heat exchanger

    NASA Technical Reports Server (NTRS)

    Swanson, Theodore D. (Inventor); Wren, deceased, Paul (Inventor)

    1998-01-01

    A capillary pumped loop for transferring heat from one body part to another body part, the capillary pumped loop comprising a capillary evaporator for vaporizing a liquid refrigerant by absorbing heat from a warm body part, a condenser for turning a vaporized refrigerant into a liquid by transferring heat from the vaporized liquid to a cool body part, a first tube section connecting an output port of the capillary evaporator to an input of the condenser, and a second tube section connecting an output of the condenser to an input port of the capillary evaporator. A wick may be provided within the condenser. A pump may be provided between the second tube section and the input port of the capillary evaporator. Additionally, an esternal heat source or heat sink may be utilized.

  9. Equilibrium capillary forces with atomic force microscopy.

    PubMed

    Sprakel, J; Besseling, N A M; Leermakers, F A M; Cohen Stuart, M A

    2007-09-07

    We present measurements of equilibrium forces resulting from capillary condensation. The results give access to the ultralow interfacial tensions between the capillary bridge and the coexisting bulk phase. We demonstrate this with solutions of associative polymers and an aqueous mixture of gelatin and dextran, with interfacial tensions around 10 microN/m. The equilibrium nature of the capillary forces is attributed to the combination of a low interfacial tension and a microscopic confinement geometry, based on nucleation and growth arguments.

  10. DNA Sequencing Using capillary Electrophoresis

    SciTech Connect

    Dr. Barry Karger

    2011-05-09

    The overall goal of this program was to develop capillary electrophoresis as the tool to be used to sequence for the first time the Human Genome. Our program was part of the Human Genome Project. In this work, we were highly successful and the replaceable polymer we developed, linear polyacrylamide, was used by the DOE sequencing lab in California to sequence a significant portion of the human genome using the MegaBase multiple capillary array electrophoresis instrument. In this final report, we summarize our efforts and success. We began our work by separating by capillary electrophoresis double strand oligonucleotides using cross-linked polyacrylamide gels in fused silica capillaries. This work showed the potential of the methodology. However, preparation of such cross-linked gel capillaries was difficult with poor reproducibility, and even more important, the columns were not very stable. We improved stability by using non-cross linked linear polyacrylamide. Here, the entangled linear chains could move when osmotic pressure (e.g. sample injection) was imposed on the polymer matrix. This relaxation of the polymer dissipated the stress in the column. Our next advance was to use significantly lower concentrations of the linear polyacrylamide that the polymer could be automatically blown out after each run and replaced with fresh linear polymer solution. In this way, a new column was available for each analytical run. Finally, while testing many linear polymers, we selected linear polyacrylamide as the best matrix as it was the most hydrophilic polymer available. Under our DOE program, we demonstrated initially the success of the linear polyacrylamide to separate double strand DNA. We note that the method is used even today to assay purity of double stranded DNA fragments. Our focus, of course, was on the separation of single stranded DNA for sequencing purposes. In one paper, we demonstrated the success of our approach in sequencing up to 500 bases. Other

  11. Capillaroscopy and the measurement of capillary pressure

    PubMed Central

    Shore, Angela C

    2000-01-01

    Capillaries play a critical role in cardiovascular function as the point of exchange of nutrients and waste products between the tissues and circulation. Studies of capillary function in man are limited by access to the vascular bed. However, skin capillaries can readily be studied by the technique of capillaroscopy which enables the investigator to assess morphology, density and blood flow velocity. It is also possible to estimate capillary pressure by direct cannulation using glass micropipettes. This review will describe the techniques used to make these assessments and will outline some of the changes that are seen in health and disease. PMID:11136289

  12. Microwave Ablation Compared to Radiofrequency Ablation for Hepatic Lesions: A Meta-Analysis.

    PubMed

    Huo, Ya Ruth; Eslick, Guy D

    2015-08-01

    To evaluate the efficacy and safety of microwave (MW) ablation compared with radiofrequency (RF) ablation for hepatic lesions by using meta-analytic techniques. Overall, 16 studies involving 2,062 patients were included. MW ablation was found to have significantly better 6-year overall survival than RF ablation (odds ratio, 1.64, 95% confidence interval, 1.15-2.35), but this was based on a few articles (n = 3 of 16). MW ablation and RF ablation had similar 1-5-year overall survival, disease-free survival, local recurrence rate, and adverse events. Based on similar safety and efficacy outcomes, either MW ablation or RF ablation may be used for effective local hepatic therapy.

  13. Tumor Thermal Ablation Enhancement by Micromaterials.

    PubMed

    Zhao, Fan; Su, Hongying; Han, Xiangjun; Bao, Han; Qi, Ji

    2016-01-07

    Thermal ablation is a minimally invasive therapeutic technique that has shown remarkable potential in treating un resectable tumors. However, clinical applications have stalled, due to safety ambiguities, slow heat induction, lengthy ablation times, and post-therapeutic monitoring issues. To further improve treatment efficacy, an assortment of micro materials (eg, nano particulates of gold, silica, or iron oxide and single-walled carbon nanotubes) are under study as thermal ablative adjuncts.In recent years, the micro material domain has become especially interesting.In vivo and in vitro animal studies have validated the use of microspheres as embolic agents in liver tumors, in advance of radiofrequency ablation. Microcapsules and micro bubbles serving as ultrasound contrast and ablation sensibilizers are strong prospects for clinical applications. This review was conducted to explore benefits of the three aforementioned micro scale technologies, in conjunction with tumor thermal ablation.

  14. Percutaneous thermal ablation of primary lung cancer.

    PubMed

    de Baere, T; Tselikas, L; Catena, V; Buy, X; Deschamps, F; Palussière, J

    2016-10-01

    Percutaneous ablation of small-size non-small-cell lung cancer (NSCLC) has demonstrated feasibility and safety in nonsurgical candidates. Radiofrequency ablation (RFA), the most commonly used technique, has an 80-90% reported rate of complete ablation, with the best results obtained in tumors less than 2-3cm in diameter. The highest one-, three-, and five-year overall survival rates reported in NSCLC following RFA are 97.7%, 72.9%, and 55.7% respectively. Tumor size, tumor stage, and underlying comorbidities are the main predictors of survival. Other ablation techniques such as microwave or cryoablation may help overcome the limitations of RFA in the future, particularly for large tumors or those close to large vessels. Stereotactic ablative radiotherapy (SABR) has its own complications and carries the risk of fiducial placement requiring multiple lung punctures. SABR has also demonstrated significant efficacy in treating small-size lung tumors and should be compared to percutaneous ablation.

  15. Image-guided ablation for hepatocellular carcinoma.

    PubMed

    Lencioni, Riccardo; Crocetti, Laura

    2013-01-01

    Image-guided ablation is accepted as the best therapeutic choice for patients with early-stage hepatocellular carcinoma (HCC) when surgical options-including resection and transplantation-are precluded. The term image-guided tumor ablation is defined as the direct application of chemical substances or sources of energy to a focal tumor in an attempt to achieve eradication or substantial tumor destruction. Over the past 25 years, several methods for local tumor destruction have been developed and clinically tested. Radiofrequency ablation (RFA) has shown superior anticancer effect and greater survival benefit with respect to the seminal percutaneous technique, ethanol injection, in meta-analyses of randomized controlled trials, and is currently established as the standard ablative modality. Nevertheless, novel thermal and nonthermal techniques for tumor ablation-including microwave ablation and irreversible electroporation-seem to have potential to improve the efficacy of RFA and are currently undergoing clinical investigation.

  16. Pelvic radiation - discharge

    MedlinePlus

    Radiation of the pelvis - discharge; Cancer treatment - pelvic radiation; Prostate cancer - pelvic radiation; Ovarian cancer - pelvic radiation; Cervical cancer - pelvic radiation; Uterine cancer - pelvic radiation; Rectal cancer - ...

  17. Horizontal microscopy in square capillaries

    NASA Astrophysics Data System (ADS)

    Moroz, Pavel E.

    1992-07-01

    Intracellular protoplasmic movements may, due to gravity, have a vertical component greater or different from the horizontal one. This makes horizontal microscopy indispensable in the search for the cellular sensor of gravity. The possibility of the latter being a cell organelle assigns special significance to high-resolution microscopy. A horizontal suction device for picking up a cell and its high-resolution horizontal microscopy in a rectangular capillary may be helpful for detection of gravity-related shifts of cellular organelles in vivo.

  18. Capillary wave spectroscopy on ferrofluids

    NASA Astrophysics Data System (ADS)

    Patzke, J.; Rathke, B.; Will, S.

    2007-12-01

    We investigate the magnetoviscous effect in ferrofluids by Capillary Wave Spectroscopy (CWS, Surface Light Scattering). This technique probes a specific mode of thermally excited surface waves giving information on surface tension and viscosity. In ferrofluids we detect a transition from propagating surface modes to overdamped ones depending on the particle concentration and strength and the orientation of an externally applied magnetic field. We interprete this effect as caused by an increase of the liquid viscosity with an increasing particle concentration and field-strength. Changing the relative orientation of the scattering vector and magnetic field shows that the viscous properties of ferrofluids in a magnetic field are anisotropic. Figs 8, Refs 12.

  19. High pressure pulsed capillary viscometry

    NASA Technical Reports Server (NTRS)

    Smith, R. L.; Walowitt, J. A.; Pan, C. H. T.

    1972-01-01

    An analytical and test program was conducted in order to establish the feasibility of a multichamber pulsed-capillary viscometer. The initial design incorporated a piston, ram, and seals which produced measured pulses up to 30,000 psi in the closed chamber system. Pressure pulses from one to ten milliseconds were investigated in a system volume of 1 cuin. Four test fluids: a MIL-L-7808, a 5P4E polyphenyl ether, a MIL-L-23699A, and a synthetic hydrocarbon were examined in the test pressure assembly. The pressure-viscosity coefficient and viscosity delay time were determined for the MIL-L-7808 lubricant tested.

  20. Capillary Bridges between Soft Substrates

    NASA Astrophysics Data System (ADS)

    Wexler, Jason S.; Heard, Tiara M.; Stone, Howard A.

    2014-02-01

    A wetting droplet trapped in the thin gap between two elastic bodies will deflect the bodies towards one another. The deformation increases the total capillary adhesion force by increasing the contact radius and narrowing the gap height. For flat droplets, with a large ratio of radius to gap height, the Laplace pressure causes surface deformations that are orders of magnitude larger than those induced by a sessile droplet of the same radius. We present experiments, scalings, and closed-form solutions that describe the deformation. Using variational techniques, we also show that the problem exhibits a bifurcation, where the gap spontaneously closes due to an incremental increase in drop volume.

  1. Plasma-mediated ablation of biofilm contamination

    NASA Astrophysics Data System (ADS)

    Guo, Zhixiong; Wang, Xiaoliang; Huang, Huan

    2010-12-01

    Ultra-short pulsed laser removal of thin biofilm contamination on different substrates has been conducted via the use of plasma-mediated ablation. The biofilms were formed using sheep whole blood. The ablation was generated using a 1.2 ps ultra-short pulsed laser with wavelength centered at 1552 nm. The blood contamination was transformed into plasma and collected with a vacuum system. The single line ablation features have been measured. The ablation thresholds of blood contamination and bare substrates were determined. It is found that the ablation threshold of the blood contamination is lower than those of the beneath substrates including the glass slide, PDMS, and human dermal tissues. The ablation effects of different laser parameters (pulse overlap rate and pulse energy) were studied and ablation efficiency was measured. Proper ablation parameters were found to efficiently remove contamination with maximum efficiency and without damage to the substrate surface for the current laser system. Complete removal of blood contaminant from the glass substrate surface and freeze-dried dermis tissue surface was demonstrated by the USP laser ablation with repeated area scanning. No obvious thermal damage was found in the decontaminated glass and tissue samples.

  2. Percutaneous ablation of hepatocellular carcinoma: current status.

    PubMed

    McWilliams, Justin P; Yamamoto, Shota; Raman, Steven S; Loh, Christopher T; Lee, Edward W; Liu, David M; Kee, Stephen T

    2010-08-01

    Hepatocellular carcinoma (HCC) is an increasingly common disease with dismal long-term survival. Percutaneous ablation has gained popularity as a minimally invasive, potentially curative therapy for HCC in nonoperative candidates. The seminal technique of percutaneous ethanol injection has been largely supplanted by newer modalities, including radiofrequency ablation, microwave ablation, cryoablation, and high-intensity focused ultrasound ablation. A review of these modalities, including technical success, survival rates, and complications, will be presented, as well as considerations for treatment planning and follow-up.

  3. Ablation of liver metastases: current status.

    PubMed

    Flanders, Vincent L; Gervais, Debra A

    2010-08-01

    Local ablative therapy for the treatment of metastatic disease to the liver has been evaluated most extensively in colorectal cancer with 5-year survival rates up to 55% after RF ablation. Recent findings suggest selected patients with other malignant processes may benefit as well, but conclusive evidence is limited. This article reviews the available literature regarding the use of radiofrequency ablation, microwave ablation, and cryoablation in the treatment of metastatic disease to the liver. The published results of each of these modalities in the treatment of metastatic disease to the liver are promising, and outcomes continue to be evaluated.

  4. Signal enhancement in laser-induced breakdown spectroscopy using fast square-pulse discharges

    NASA Astrophysics Data System (ADS)

    Sobral, H.; Robledo-Martinez, A.

    2016-10-01

    A fast, high voltage square-shaped electrical pulse initiated by laser ablation was investigated as a means to enhance the analytical capabilities of laser Induced breakdown spectroscopy (LIBS). The electrical pulse is generated by the discharge of a charged coaxial cable into a matching impedance. The pulse duration and the stored charge are determined by the length of the cable. The ablation plasma was produced by hitting an aluminum target with a nanosecond 532-nm Nd:YAG laser beam under variable fluence 1.8-900 J cm- 2. An enhancement of up to one order of magnitude on the emission signal-to-noise ratio can be achieved with the spark discharge assisted laser ablation. Besides, this increment is larger for ionized species than for neutrals. LIBS signal is also increased with the discharge voltage with a tendency to saturate for high laser fluences. Electron density and temperature evolutions were determined from time delays of 100 ns after laser ablation plasma onset. Results suggest that the spark discharge mainly re-excites the laser produced plume.

  5. Analysis of iodinated contrast delivered during thermal ablation: is material trapped in the ablation zone?

    NASA Astrophysics Data System (ADS)

    Wu, Po-hung; Brace, Chris L.

    2016-08-01

    Intra-procedural contrast-enhanced CT (CECT) has been proposed to evaluate treatment efficacy of thermal ablation. We hypothesized that contrast material delivered concurrently with thermal ablation may become trapped in the ablation zone, and set out to determine whether such an effect would impact ablation visualization. CECT images were acquired during microwave ablation in normal porcine liver with: (A) normal blood perfusion and no iodinated contrast, (B) normal perfusion and iodinated contrast infusion or (C) no blood perfusion and residual iodinated contrast. Changes in CT attenuation were analyzed from before, during and after ablation to evaluate whether contrast was trapped inside of the ablation zone. Visualization was compared between groups using post-ablation contrast-to-noise ratio (CNR). Attenuation gradients were calculated at the ablation boundary and background to quantitate ablation conspicuity. In Group A, attenuation decreased during ablation due to thermal expansion of tissue water and water vaporization. The ablation zone was difficult to visualize (CNR  =  1.57  ±  0.73, boundary gradient  =  0.7  ±  0.4 HU mm-1), leading to ablation diameter underestimation compared to gross pathology. Group B ablations saw attenuation increase, suggesting that iodine was trapped inside the ablation zone. However, because the normally perfused liver increased even more, Group B ablations were more visible than Group A (CNR  =  2.04  ±  0.84, boundary gradient  =  6.3  ±  1.1 HU mm-1) and allowed accurate estimation of the ablation zone dimensions compared to gross pathology. Substantial water vaporization led to substantial attenuation changes in Group C, though the ablation zone boundary was not highly visible (boundary gradient  =  3.9  ±  1.1 HU mm-1). Our results demonstrate that despite iodinated contrast being trapped in the ablation zone, ablation visibility was

  6. Cryogenic Capillary Screen Heat Entrapment

    NASA Technical Reports Server (NTRS)

    Bolshinskiy, L.G.; Hastings, L.J.; Stathman, G.

    2007-01-01

    Cryogenic liquid acquisition devices (LADs) for space-based propulsion interface directly with the feed system, which can be a significant heat leak source. Further, the accumulation of thermal energy within LAD channels can lead to the loss of sub-cooled propellant conditions and result in feed system cavitation during propellant outflow. Therefore, the fundamental question addressed by this program was: "To what degree is natural convection in a cryogenic liquid constrained by the capillary screen meshes envisioned for LADs.?"Testing was first conducted with water as the test fluid, followed by LN2 tests. In either case, the basic experimental approach was to heat the bottom of a cylindrical column of test fluid to establish stratification patterns measured by temperature sensors located above and below a horizontal screen barrier position. Experimentation was performed without barriers, with screens, and with a solid barrier. The two screen meshes tested were those typically used by LAD designers, "200x1400" and "325x2300", both with Twill Dutch Weave. Upon consideration of both the water and LN2 data it was concluded that heat transfer across the screen meshes was dependent upon barrier thermal conductivity and that the capillary screen meshes were impervious to natural convection currents.

  7. Atomic Force Controlled Capillary Electrophoresis

    NASA Astrophysics Data System (ADS)

    Lewis, Aaron; Yeshua, Talia; Palchan, Mila; Lovsky, Yulia; Taha, Hesham

    2010-03-01

    Lithography based on scanning probe microscopic techniques has considerable potential for accurate & localized deposition of material on the nanometer scale. Controlled deposition of metallic features with high purity and spatial accuracy is of great interest for circuit edit applications in the semiconductor industry, for plasmonics & nanophotonics and for basic research in surface enhanced Raman scattering & nanobiophysics. Within the context of metal deposition we will review the development of fountain pen nanochemistry and its most recent emulation Atomic Force Controlled Capillary Electrophoresis (ACCE). Using this latter development we will demonstrate achievement of unprecedented control of nanoparticle deposition using a three-electrode geometry. Three electrodes are attached: one on the outside of a metal coated glass probe, one on the inside of a hollow probe in a solution containing Au nanoparticles in the capillary, and a third on the surface where the writing takes place. The three electrodes provide electrical pulses for accurate control of deposition and retraction of the liquid from the surface overcoming the lack of control seen in both dip pen lithography & fountain pen nanochemistry when the tip contacts the surface. With this development, we demonstrate depositing a single 1.3 nm Au nanoparticle onto surfaces such as semiconductors.

  8. Evaluation of capillary reinforced composites

    NASA Technical Reports Server (NTRS)

    Cahill, J. E.; Halase, J. F.; South, W. K.; Stoffer, L. J.

    1985-01-01

    Anti-icing of the inlet of jet engines is generally performed with high pressure heated air that is directed forward from the compressor through a series of pipes to various manifolds located near the structures to be anti-iced. From these manifolds, the air is directed to all flowpath surfaces that may be susceptible to ice formation. There the anti-icing function may be performed by either heat conduction or film heating. Unfortunately, the prospect of utilizing lighweight, high strength composites for inlet structures of jet engines has been frustrated by the low transverse thermal conductivity of such materials. It was the objective of this program to develop an advanced materials and design concept for anti-icing composite structures. The concept that was evaluated used capillary glass tubes embedded on the surface of a composite structure with heated air ducted through the tubes. An analytical computer program was developed to predict the anti-icing performance of such tubes and a test program was conducted to demonstrate actual performance of this system. Test data and analytical code results were in excellent agreement. Both indicate feasibility of using capillary tubes for surface heating as a means for composite engine structures to combat ice accumulation.

  9. Capillary Rise in Porous Media.

    PubMed

    Lago, Marcelo; Araujo, Mariela

    2001-02-01

    Capillary rise experiments were performed in columns filled with glass beads and Berea sandstones, using visual methods to register the advance of the water front. For the glass bead filled columns, early time data are well fitted by the Washburn equation. However, in the experiments, the advancing front exceeded the predicted equilibrium height. For large times, an algebraic behavior of the velocity of the front is observed (T. Delker et al., Phys. Rev. Lett. 76, 2902 (1996)). A model for studying the capillary pressure evolution in a regular assembly of spheres is proposed and developed. It is based on a quasi-static advance of the meniscus with a piston-like motion and allows us to estimate the hydraulic equilibrium height, with values very close to those obtained by fitting early time data to a Washburn equation. The change of regime is explained as a transition in the mechanism of advance of the meniscus. On the other hand, only the Washburn regime was observed for the sandstones. The front velocity was fitted to an algebraical form with an exponent close to 0.5, a value expected from the asymptotic limit of the Washburn equation. Copyright 2001 Academic Press.

  10. Graywater Discharges from Vessels

    DTIC Science & Technology

    2011-11-01

    of members is 55; however, two have holding tanks and discharge shore-side and a third vessel is the car ferry Badger that discharges shore-side...Alaskan waters, and in numerous European ports such as Venice and Oslo ever since 2003. Model Capacitiy Load Installed Power

  11. Lithium battery discharge tests

    NASA Technical Reports Server (NTRS)

    Johnson, C. J.

    1980-01-01

    The long term discharge of a variety of lithium cells was characterized and the susceptibility of the cells to chemical variation during the slow discharge was tested. A shunt resistor was set across the terminals to monitor the voltage as a function of time. Failures were identified by premature voltage drops.

  12. Longitudinal discharge laser electrodes

    DOEpatents

    Warner, B.E.; Miller, J.L.; Ault, E.R.

    1994-08-23

    The improved longitudinal discharge laser electrode with IR baffle includes an electrode made up of washers spaced along the laser axis in order to form inter-washer spaces for hollow cathode discharge to take place and for IR radiation to be trapped. Additional IR baffles can be placed between the electrode ann the window. 2 figs.

  13. Longitudinal discharge laser electrodes

    DOEpatents

    Warner, Bruce E.; Miller, John L.; Ault, Earl R.

    1994-01-01

    The improved longitudinal discharge laser electrode with IR baffle includes an electrode made up of washers spaced along the laser axis in order to form inter-washer spaces for hollow cathode discharge to take place and for IR radiation to be trapped. Additional IR baffles can be placed between the electrode ann the window.

  14. Sheathless interface for coupling capillary electrophoresis with mass spectrometry

    DOEpatents

    Wang, Chenchen; Tang, Keqi; Smith, Richard D.

    2014-06-17

    A sheathless interface for coupling capillary electrophoresis (CE) with mass spectrometry is disclosed. The sheathless interface includes a separation capillary for performing CE separation and an emitter capillary for electrospray ionization. A portion of the emitter capillary is porous or, alternatively, is coated to form an electrically conductive surface. A section of the emitter capillary is disposed within the separation capillary, forming a joint. A metal tube, containing a conductive liquid, encloses the joint.

  15. Internal capillary insulation for cryogenic tanks

    NASA Technical Reports Server (NTRS)

    Mcgrew, J. L.

    1972-01-01

    Capillary-type insulation was devised for installation on inside of liquid methane fuel tanks for future aircraft. Insulation consists of honeycomb core of fiberglass cloth impregnated with polyimide resin which is bonded onto metal tank wall using polyimide adhesive. Capillary holes in each honeycomb cell admit methane which provides static pressure in cell.

  16. Capillary waveguide optrodes for Medical applications

    NASA Astrophysics Data System (ADS)

    Kieslinger, Dietmar; Weigl, Bernhard H.; Draxler, Sonja; Lippitsch, Max E.

    1997-01-01

    Glass capillaries with a chemically sensitive coating on the inner surface are used as optical sensors for medical diagnostics. The capillary simultaneously serves as a sample compartment, a sensor element, and an inhomogeneous optical waveguide. Different optical setups have been investigated and compared regarding its waveguiding properties.

  17. Capillary electrophoresis using core-based hyperbranched polyethyleneimine (CHPEI) static-coated capillaries.

    PubMed

    Boonyakong, Cheerapa; Tucker, Sheryl A

    2009-10-01

    With unique 3-D architecture, the application of core-based hyperbranched polyethyleneimine (CHPEI), as a capillary coating in capillary electrophoresis, is demonstrated by manipulation of the electroosmotic mobility (EOF). CHPEI coatings (CHPEI5, M(w) approximately 5000 and CHPEI25, M(w) approximately 25,000) were physically adsorbed onto the inner surface of bare fused-silica capillary (BFS) via electrostatic interaction of the oppositely charged molecules by rinsing the capillaries with different CHPEI aqueous solutions. The EOF values of the coated capillaries were measured over the pH range of 4.0-9.0. At higher pH (pH >6) the coated capillary surface possesses excess negative charges, which causes the reversal of the EOF. The magnitudes of the EOF obtained from the coated capillaries were three-fold lower than that of BFS capillary. Desirable reproducibility of the EOF with % RSD (n = 5) < or = 2 was obtained. Effect of ionic strength, stability of the coating (% RSD = 0.3) and the dependence of the EOF on pH (% RSD = 0.5) were also investigated. The CHPEI-coated capillaries were successfully utilized to separate phenolic compounds, B vitamins, as well as basic drugs and related compounds with reasonable analysis time (< 20 min) and acceptable migration-time repeatability (< 0.7% RSD for intra-capillary and < 2% RSD for inter-capillary).

  18. Co-axial discharges

    DOEpatents

    Luce, J. S.; Smith, L. P.

    1960-11-22

    An apparatus is described for producing coaxial arc discharges in an evacuated enclosure and within a strong, confining magnetic field. The arcs are maintained at a high potential difference. Electrons diffuse to the more positive arc from the negative arc, and positive ions diffuse from the more positive arc to the negative arc. Coaxial arc discharges have the advantuge that ions that return to strike the positive arc discharge will lose no energy since they do not strike a solid wall or electrode. These discharges are useful in confining an ionized plasma between the discharges and have the advantage of preventing impurities from the walls of the enclosure from entering the plasma area because of the arc barrier set up by the cylindrical outer arc. (auth)

  19. CO-AXIAL DISCHARGES

    DOEpatents

    Luce, J.S.; Smith, L.P.

    1960-11-22

    A method and apparatus are given for producing coaxial arc discharges in an evacuated enclosure and within a strong, confining magnetic field. The arcs are maintained at a high potential difference. Electrons will diffuse to the more positive arc from the negative arc, and positive ions will diffuse from the more positive arc to the negative arc. Coaxial arc discharges have the advantage that ions which return to strike the positive arc discharge will lose no energy since they do not strike a solid wall or electrode. Those discharges are useful in confining an ionized plasma between the discharges, and have the advantage of preventing impurities from the walls of the enclosure from entering ihe plasma area because of the arc barrier set up bv the cylindrical outer arc.

  20. GAS DISCHARGE DEVICES

    DOEpatents

    Jefferson, S.

    1958-11-11

    An apparatus utilized in introducing tritium gas into envelope of a gas discharge device for the purpose f maintaining the discharge path in ionized condition is described. ln addition to the cathode and anode, the ischarge device contains a zirconium or tantalum ilament arranged for external excitation and a metallic seed containing tritium, and also arranged to have a current passed through it. Initially, the zirconium or tantalum filament is vaporized to deposit its material adjacent the main discharge region. Then the tritium gas is released and, due to its affinity for the first released material, it deposits in the region of the main discharge where it is most effective in maintaining the discharge path in an ionized condition.

  1. HOLLOW CARBON ARC DISCHARGE

    DOEpatents

    Luce, J.S.

    1960-10-11

    A device is described for producing an energetic, direct current, hollow, carbon-arc discharge in an evacuated container and within a strong magnetic field. Such discharges are particularly useful not only in dissociation and ionization of high energy molecular ion beams, but also in acting as a shield or barrier against the instreaming of lowenergy neutral particles into a plasma formed within the hollow discharge when it is used as a dissociating mechanism for forming the plasma. There is maintained a predetermined ratio of gas particles to carbon particles released from the arc electrodes during operation of the discharge. The carbon particles absorb some of the gas particles and are pumped along and by the discharge out of the device, with the result that smaller diffusion pumps are required than would otherwise be necessary to dispose of the excess gas.

  2. Laser Navigation for Radiofrequency Ablation

    SciTech Connect

    Varro, Zoltan; Locklin, Julia K. Wood, Bradford J.

    2004-09-15

    A 45-year-old male with renal cell carcinoma secondary to von-Hippel Lindau (VHL) disease presented for radiofrequency ablation (RFA) of kidney tumors. Due to his prior history of several partial nephrectomies and limited renal reserve, RFA was chosen because of its relatively nephron-sparing nature. A laser guidance device was used to help guide probe placement in an attempt to reduce procedure time and improve targeting accuracy. The device was successful at guiding needle placement, as both tumors were located with a single pass. Follow-up CT scan confirmed accurate needle placement, showing an area of coagulation necrosis covering the previously seen tumor.

  3. Improving Hospital Discharge Time

    PubMed Central

    El-Eid, Ghada R.; Kaddoum, Roland; Tamim, Hani; Hitti, Eveline A.

    2015-01-01

    Abstract Delays in discharging patients can impact hospital and emergency department (ED) throughput. The discharge process is complex and involves setting specific challenges that limit generalizability of solutions. The aim of this study was to assess the effectiveness of using Six Sigma methods to improve the patient discharge process. This is a quantitative pre and post-intervention study. Three hundred and eighty-six bed tertiary care hospital. A series of Six Sigma driven interventions over a 10-month period. The primary outcome was discharge time (time from discharge order to patient leaving the room). Secondary outcome measures included percent of patients whose discharge order was written before noon, percent of patients leaving the room by noon, hospital length of stay (LOS), and LOS of admitted ED patients. Discharge time decreased by 22.7% from 2.2 hours during the preintervention period to 1.7 hours post-intervention (P < 0.001). A greater proportion of patients left their room before noon in the postintervention period (P < 0.001), though there was no statistical difference in before noon discharge. Hospital LOS dropped from 3.4 to 3.1 days postintervention (P < 0.001). ED mean LOS of patients admitted to the hospital was significantly lower in the postintervention period (6.9 ± 7.8 vs 5.9 ± 7.7 hours; P < 0.001). Six Sigma methodology can be an effective change management tool to improve discharge time. The focus of institutions aspiring to tackle delays in the discharge process should be on adopting the core principles of Six Sigma rather than specific interventions that may be institution-specific. PMID:25816029

  4. Study of Capillary-Based Gaseous Detectors

    NASA Astrophysics Data System (ADS)

    Iacobaeus, C.; Francke, T.; Danielsson, M.; Ostling, J.; Peskov, V.

    2004-06-01

    We have studied gain vs. voltage characteristics and position resolutions of multistep capillary plates (two or three capillary plates operating in a cascade), as well as capillary plates operating in a mode when the main amplification occurs between plates or between the capillary plate and the readout plate (parallel plate amplification mode). Results of these studies demonstrated that in the parallel-plate amplification mode one can reach both high gains (>100000) and good position resolutions (~100 micro meter) even with a single step arrangement. It offers a compact amplification structure, which can be used in many applications. For example, in preliminary tests we succeeded to combine it with a photocathode and use it as a position sensitive gaseous photomultiplier. CsI coated capillary plates could also be used as a high position resolution and high rate X-ray converter.

  5. Oximetry of retinal capillaries by multicomponent analysis.

    PubMed

    Furukawa, Hiromitsu; Arimoto, Hidenobu; Shirai, Tomohiro; Ooto, Sotaro; Hangai, Masanori; Yoshimura, Nagahisa

    2012-08-01

    Retinal oximetry of capillaries was performed for early detection of retinal vascular abnormalities, which are caused predominantly by complications of systemic circulatory diseases. As the conventional method for determining absorbance is not applicable to capillaries, multicomponent analysis was used to estimate the absorbance spectra of the retinal blood vessels. In this analysis, the capillary spectrum was classified as intermediate between those of the retinal arteries and veins, enabling relative estimation of oxygen saturation in the capillaries. This method could be useful for early recognition of disturbances in the peripheral circulation. Furthermore, a spectroscopic ophthalmoscope system based on the proposed method was developed to examine the human retina. A clinical trial of this system demonstrated that oximetry of the retinal capillaries may be an improvement over the present diagnosis for patients of malignant hypertension.

  6. Possible role for cryoballoon ablation of right atrial appendage tachycardia when conventional ablation fails.

    PubMed

    Amasyali, Basri; Kilic, Ayhan

    2015-06-01

    Focal atrial tachycardia arising from the right atrial appendage usually responds well to radiofrequency ablation; however, successful ablation in this anatomic region can be challenging. Surgical excision of the right atrial appendage has sometimes been necessary to eliminate the tachycardia and prevent or reverse the resultant cardiomyopathy. We report the case of a 48-year-old man who had right atrial appendage tachycardia resistant to multiple attempts at ablation with use of conventional radiofrequency energy guided by means of a 3-dimensional mapping system. The condition led to cardiomyopathy in 3 months. The arrhythmia was successfully ablated with use of a 28-mm cryoballoon catheter that had originally been developed for catheter ablation of paroxysmal atrial fibrillation. To our knowledge, this is the first report of cryoballoon ablation without isolation of the right atrial appendage. It might also be an alternative to epicardial ablation or surgery when refractory atrial tachycardia originates from the right atrial appendage.

  7. Local Ablation for Hepatocellular Carcinoma in Taiwan

    PubMed Central

    Lin, Shi-Ming

    2013-01-01

    Hepatocellular carcinoma (HCC) is the second commonest cancer in Taiwan. The national surveillance program can detect HCC in its early stages, and various curative modalities (including surgical resection, orthotopic liver transplantation, and local ablation) are employed for the treatment of small HCC. Local ablation therapies are currently advocated for early-stage HCC that is unresectable because of co-morbidities, the need to preserve liver function, or refusal of resection. Among the various local ablation therapies, the most commonly used modalities include percutaneous ethanol injection and radiofrequency ablation (RFA); percutaneous acetic acid injection and microwave ablation are used less often. RFA is more commonly employed than other local ablative modalities in Taiwan because the technique is highly effective, minimally invasive, and requires fewer sessions. RFA is therefore advocated in Taiwan as the first-line curative therapy for unresectable HCC or even for resectable HCC. However, current RFA procedures are less effective against tumors that are in high-risk or difficult-to-ablate locations, are poorly visualized on ultrasonography (US), or are large. Recent advancements in RFA in Taiwan can resolve these issues by the creation of artificial ascites or pleural effusion, application of real-time virtual US assistance, use of combination therapy before RFA, or use of switching RF controllers with multiple electrodes. This review article provides updates on the clinical outcomes and advances in local ablative modalities (mostly RFA) for HCC in Taiwan. PMID:24159599

  8. Testing and evaluation of light ablation decontamination

    SciTech Connect

    Demmer, R.L.; Ferguson, R.L.

    1994-10-01

    This report details the testing and evaluation of light ablation decontamination. It details WINCO contracted research and application of light ablation efforts by Ames Laboratory. Tests were conducted with SIMCON (simulated contamination) coupons and REALCON (actual radioactive metal coupons) under controlled conditions to compare cleaning effectiveness, speed and application to plant process type equipment.

  9. Effective temperatures of polymer laser ablation

    NASA Astrophysics Data System (ADS)

    Furzikov, Nickolay P.

    1991-09-01

    Effective temperatures of laser ablation of certain polymers are extracted from experimental dependences of ablation depths on laser fluences. Dependence of these temperatures on laser pulse durations is established. Comparison with the known thermodestruction data shows that the effective temperature corresponds to transient thermodestruction proceeding by the statistically most probable way.

  10. Ablative therapies for small renal tumours.

    PubMed

    Castro, Arturo; Jenkins, Lawrence C; Salas, Nelson; Lorber, Gideon; Leveillee, Raymond J

    2013-05-01

    Improvements in imaging technology have resulted in an increase in detection of small renal masses (SRMs). Minimally invasive ablation modalities, including cryoablation, radiofrequencey ablation, microwave ablation and irreversible electroporation, are currently being used to treat SRMs in select groups of patients. Cryoablation and radiofrequency ablation have been extensively studied. Presently, cryoablation is gaining popularity because the resulting ice ball can be visualized easily using ultrasonography. Tumour size and location are strong predictors of outcome of radiofrequency ablation. One of the main benefits of microwave ablation is that microwaves can propagate through all types of tissue, including desiccated and charred tissue, as well as water vapour, which might be formed during the ablation. Irreversible electroporation has been shown in animal studies to affect only the cell membrane of undesirable target tissues and to spare adjacent structures; however, clinical studies that depict the efficacy and safety of this treatment modality in humans are still sparse. As more experience is gained in the future, ablation modalities might be utilized in all patients with tumours <4 cm in diameter, rather than just as an alternative treatment for high-risk surgical patients.

  11. Lung Cancer Ablation: Technologies and Techniques

    PubMed Central

    Alexander, Erica S.; Dupuy, Damian E.

    2013-01-01

    The incidence of lung cancers in 2012 is estimated to reach 226,160 new cases, with only a third of patients suitable surgical candidates. Tumor ablation has emerged as an important and efficacious treatment option for nonsurgical lung cancer patients. This localized minimally invasive therapy is best suited for small oligonodular lesions or favorably located metastatic tumors. Radiofrequency ablation has been in use for over a decade, and newer modalities including microwave ablation, cryoablation, and irreversible electroporation have emerged as additional treatment options for patients. Ablation therapies can offer patients and clinicians a repeatable and effective therapy for palliation and, in some cases, cure of thoracic malignancies. This article discusses the available technologies and techniques available for tumor ablation of thoracic malignancies including patient selection, basic aspects of procedure technique, imaging follow-up, treatment outcomes, and comparisons between various therapies. PMID:24436530

  12. Lung cancer ablation: technologies and techniques.

    PubMed

    Alexander, Erica S; Dupuy, Damian E

    2013-06-01

    The incidence of lung cancers in 2012 is estimated to reach 226,160 new cases, with only a third of patients suitable surgical candidates. Tumor ablation has emerged as an important and efficacious treatment option for nonsurgical lung cancer patients. This localized minimally invasive therapy is best suited for small oligonodular lesions or favorably located metastatic tumors. Radiofrequency ablation has been in use for over a decade, and newer modalities including microwave ablation, cryoablation, and irreversible electroporation have emerged as additional treatment options for patients. Ablation therapies can offer patients and clinicians a repeatable and effective therapy for palliation and, in some cases, cure of thoracic malignancies. This article discusses the available technologies and techniques available for tumor ablation of thoracic malignancies including patient selection, basic aspects of procedure technique, imaging follow-up, treatment outcomes, and comparisons between various therapies.

  13. Femtosecond ablation of ultrahard materials

    NASA Astrophysics Data System (ADS)

    Dumitru, G.; Romano, V.; Weber, H. P.; Sentis, M.; Marine, W.

    Several ultrahard materials and coatings of definite interest for tribological applications were tested with respect to their response when irradiated with fs laser pulses. Results on cemented tungsten carbide and on titanium carbonitride are reported for the first time and compared with outcomes of investigations on diamond and titanium nitride. The experiments were carried out in air, in a regime of 5-8 J/cm2 fluences, using the beam of a commercial Ti:sapphire laser. The changes induced in the surface morphology were analysed with a Nomarski optical microscope, and with SEM and AFM techniques. From the experimental data and from the calculated incident energy density distributions, the damage and ablation threshold values were determined. As expected, the diamond showed the highest threshold, while the cemented tungsten carbide exhibited typical values for metallic surfaces. The ablation rates determined (under the above-mentioned experimental conditions) were in the range 0.1-0.2 μm per pulse for all the materials investigated.

  14. Ablative shielding for hypervelocity projectiles

    NASA Technical Reports Server (NTRS)

    Rucker, Michelle A. (Inventor)

    1993-01-01

    A hypervelocity projectile shield which includes a hollow semi-flexible housing fabricated from a plastic like, or otherwise transparent membrane which is filled with a fluid (gas or liquid) is presented. The housing has a inlet valve, similar to that on a tire or basketball, to introduce an ablating fluid into the housing. The housing is attached by a Velcro mount or double-sided adhesive tape to the outside surface of a structure to be protected. The housings are arrayed in a side-by-side relationship for complete coverage of the surface to be protected. In use, when a hypervelocity projectile penetrates the outer wall of a housing it is broken up and then the projectile is ablated as it travels through the fluid, much like a meteorite 'burns up' as it enters the earth's atmosphere, and the housing is deflated. The deflated housing can be easily spotted for replacement, even from a distance. Replacement is then accomplished by simply pulling a deflated housing off the structure and installing a new housing.

  15. Tumor Ablation with Irreversible Electroporation

    PubMed Central

    Al-Sakere, Bassim; André, Franck; Bernat, Claire; Connault, Elisabeth; Opolon, Paule; Davalos, Rafael V.; Rubinsky, Boris; Mir, Lluis M.

    2007-01-01

    We report the first successful use of irreversible electroporation for the minimally invasive treatment of aggressive cutaneous tumors implanted in mice. Irreversible electroporation is a newly developed non-thermal tissue ablation technique in which certain short duration electrical fields are used to permanently permeabilize the cell membrane, presumably through the formation of nanoscale defects in the cell membrane. Mathematical models of the electrical and thermal fields that develop during the application of the pulses were used to design an efficient treatment protocol with minimal heating of the tissue. Tumor regression was confirmed by histological studies which also revealed that it occurred as a direct result of irreversible cell membrane permeabilization. Parametric studies show that the successful outcome of the procedure is related to the applied electric field strength, the total pulse duration as well as the temporal mode of delivery of the pulses. Our best results were obtained using plate electrodes to deliver across the tumor 80 pulses of 100 µs at 0.3 Hz with an electrical field magnitude of 2500 V/cm. These conditions induced complete regression in 12 out of 13 treated tumors, (92%), in the absence of tissue heating. Irreversible electroporation is thus a new effective modality for non-thermal tumor ablation. PMID:17989772

  16. Simple model for ablative stabilization

    NASA Astrophysics Data System (ADS)

    Mikaelian, Karnig O.

    1992-11-01

    We present a simple analytic model for ablative stablization of the Rayleigh-Taylor instability. In this model the effect of ablation is to move the peak of the perturbations to the location of peak pressure. This mechanism enhances the density-gradient stabilization, which is effective at short wavelengths, and it also enhances the stabilization of long-wavelength perturbations due to finite shell thickness. We consider the following density profile: exponential blowoff plasma with a density gradient β, followed by a constant-density shell of thickness δt. For perturbations of arbitrary wave number k, we present an explicit expression for the growth rate γ as a function of k, β, and δt. We find that ``thick'' shells defined by β δt>=1 have γ2>=0 for any k, while ``thin'' shells defined by β δt<1 can have γ2<0 for small k, reflecting stability by proximity to the back side of the shell. We also present lasnex simulations that are in good agreement with our analytic formulas.

  17. Stellar Ablation of Planetary Atmospheres

    NASA Technical Reports Server (NTRS)

    Moore, Thomas E.; Horwitz, J. L.

    2007-01-01

    We review observations and theories of the solar ablation of planetary atmospheres, focusing on the terrestrial case where a large magnetosphere holds off the solar wind, so that there is little direct atmospheric impact, but also couples the solar wind electromagnetically to the auroral zones. We consider the photothermal escape flows known as the polar wind or refilling flows, the enhanced mass flux escape flows that result from localized solar wind energy dissipation in the auroral zones, and the resultant enhanced neutral atom escape flows. We term these latter two escape flows the "auroral wind." We review observations and theories of the heating and acceleration of auroral winds, including energy inputs from precipitating particles, electromagnetic energy flux at magnetohydrodynamic and plasma wave frequencies, and acceleration by parallel electric fields and by convection pickup processes also known as "centrifugal acceleration." We consider also the global circulation of ionospheric plasmas within the magnetosphere, their participation in magnetospheric disturbances as absorbers of momentum and energy, and their ultimate loss from the magnetosphere into the downstream solar wind, loading reconnection processes that occur at high altitudes near the magnetospheric boundaries. We consider the role of planetary magnetization and the accumulating evidence of stellar ablation of extrasolar planetary atmospheres. Finally, we suggest and discuss future needs for both the theory and observation of the planetary ionospheres and their role in solar wind interactions, to achieve the generality required for a predictive science of the coupling of stellar and planetary atmospheres over the full range of possible conditions.

  18. Two-dimensional capillary origami

    NASA Astrophysics Data System (ADS)

    Brubaker, N. D.; Lega, J.

    2016-01-01

    We describe a global approach to the problem of capillary origami that captures all unfolded equilibrium configurations in the two-dimensional setting where the drop is not required to fully wet the flexible plate. We provide bifurcation diagrams showing the level of encapsulation of each equilibrium configuration as a function of the volume of liquid that it contains, as well as plots representing the energy of each equilibrium branch. These diagrams indicate at what volume level the liquid drop ceases to be attached to the endpoints of the plate, which depends on the value of the contact angle. As in the case of pinned contact points, three different parameter regimes are identified, one of which predicts instantaneous encapsulation for small initial volumes of liquid.

  19. Capillary Separation: Micellar Electrokinetic Chromatography

    NASA Astrophysics Data System (ADS)

    Terabe, Shigeru

    2009-07-01

    Micellar electrokinetic chromatography (MEKC), a separation mode of capillary electrophoresis (CE), has enabled the separation of electrically neutral analytes. MEKC can be performed by adding an ionic micelle to the running solution of CE without modifying the instrument. Its separation principle is based on the differential migration of the ionic micelles and the bulk running buffer under electrophoresis conditions and on the interaction between the analyte and the micelle. Hence, MEKC's separation principle is similar to that of chromatography. MEKC is a useful technique particularly for the separation of small molecules, both neutral and charged, and yields high-efficiency separation in a short time with minimum amounts of sample and reagents. To improve the concentration sensitivity of detection, several on-line sample preconcentration techniques such as sweeping have been developed.

  20. Copolymers For Capillary Gel Electrophoresis

    SciTech Connect

    Liu, Changsheng; Li, Qingbo

    2005-08-09

    This invention relates to an electrophoresis separation medium having a gel matrix of at least one random, linear copolymer comprising a primary comonomer and at least one secondary comonomer, wherein the comonomers are randomly distributed along the copolymer chain. The primary comonomer is an acrylamide or an acrylamide derivative that provides the primary physical, chemical, and sieving properties of the gel matrix. The at least one secondary comonomer imparts an inherent physical, chemical, or sieving property to the copolymer chain. The primary and secondary comonomers are present in a ratio sufficient to induce desired properties that optimize electrophoresis performance. The invention also relates to a method of separating a mixture of biological molecules using this gel matrix, a method of preparing the novel electrophoresis separation medium, and a capillary tube filled with the electrophoresis separation medium.

  1. Glow discharge detector

    DOEpatents

    Koo, Jackson C.; Yu, Conrad M.

    2002-01-01

    A highly sensitive electronic ion cell for the measurement of trace elements in He carrier gas which involves glow discharge. A constant wave (CW) glow discharge detector which is controlled through a biased resistor, can detect the change of electron density caused by impurities in the He carrier gas by many orders of magnitude larger than that caused by direct ionization or electron capture. The glow discharge detector utilizes a floating pseudo-electrode to form a probe in or near the plasma. By using this probe, the large variation of electron density due to trace amounts of impurities can be directly measured.

  2. INTENSE ENERGETIC GAS DISCHARGE

    DOEpatents

    Luce, J.S.

    1960-03-01

    A method and apparatus for initiating and sustaining an energetic gas arc discharge are described. A hollow cathode and a hollow anode are provided. By regulating the rate of gas flow into the interior of the cathode, the arc discharge is caused to run from the inner surface of the cathode with the result that adequate space-charge neutralization is provided inside the cathode but not in the main arc volume. Thus, the gas fed to the cathode is substantially completely ionized before it leaves the cathode, with the result that an energetic arc discharge can be maintained at lower operating pressures.

  3. Discharge lamp technologies

    NASA Technical Reports Server (NTRS)

    Dakin, James

    1994-01-01

    This talk is an overview of discharge lamp technology commonly employed in general lighting, with emphasis on issues pertinent to lighting for plant growth. Since the audience is primarily from the plant growth community, and this begins the light source part of the program, we will start with a brief description of the discharge lamps. Challenges of economics and of thermal management make lamp efficiency a prime concern in controlled environment agriculture, so we will emphasize science considerations relating to discharge lamp efficiency. We will then look at the spectra and ratings of some representative lighting products, and conclude with a discussion of technological advances.

  4. Capillary Properties of Model Pores.

    NASA Astrophysics Data System (ADS)

    Walsh, Tim J.

    Available from UMI in association with The British Library. Liquid menisci in small pores exhibit a curved surface across which there is a significant pressure difference. In the past it has been difficult to calculate the curvatures, of this class of menisci. Some recent studies have shown that a relatively straightforward, but hitherto neglected, method originated by Mayer & Stowe (1965) and Princen (1969a) can be applied to analyse wedging menisci. However, the method has lacked a comprehensive experimental verification. This investigation follows on from the previously limited studies. A standardised method for the application of the analysis is described, the results from which are compared to observations made using modified experimental procedures. The behaviour of the capillary surfaces formed in several model pores are analysed with the method. The model systems studied are rectangular ducts, the pores formed by a rod in an angled corner, by two contacting rods and a plate and the space between a rod and a plate. For the latter two shapes the analysis is extended to include systems of mixed wettability which have a particular bearing on enhanced oil recovery operations. Experiments in which curvatures are inferred from observations of capillary rise, are performed using two comparative techniques. An involved procedure confirms predictions of meniscus curvature to within 0.3%. Use of a more straightforward, through less accurate, technique enables variations of curvature with tube shape or contact angle(s) to be conveniently studied. Results obtained are excellent and confirm the theory within the determined experimental errors. (Abstract shortened by UMI.).

  5. ICPP: Transient Electrical Discharges in Small Devices

    NASA Astrophysics Data System (ADS)

    Soto, Leopoldo

    2000-10-01

    Small devices of low energy and high power are used to study the basic physics and applications of transient electrical discharges. Three experiments are discussed: a) ionization processes and early stage of a Z-pinch under various initial conditions driven by a small generator (10^12 A/s current derivative) (1, 2) , b) high brightness VUV to soft X-ray emission from a fast capillary discharge (5ns rise time, 5kA peak current and 10^12 A/s current derivative) (3), c) neutron pulses (10^4 -10^5 neutrons per pulse) from a small plasma focus (160 nF capacitor bank, 100 - 200 J energy storage) (4). The last device is oriented to repetitive neutron pulses for substance detection. Numerical simulations of the MHD equations have been carried out to assist the experimental design and diagnostics. The diagnostics developed include current and voltage monitors, multipinhole camera with a multichannel plate (four frames, one frame every 4 ns), in order to obtain the plasma dynamics. Also, 1 ns pulse interferometry was implemented to observe the evolution of the electron density profiles. In addition, VUV spectroscopy was applied to characterize the capillary discharge. Electrical characterization of the plasma focus was established. A comprehensive picture of the plasma dynamics and radiation emission behavior is obtained. This work has been funded by FONDECYT grant 1980187 and a Presidential Chair in Science granted by Chilean government. Part of this work, in collaboration with PLADEMA, Argentina (Bilateral agreement CNEA-CCHEN) and in collaboration with Institute of Spectroscopy, ISAN, Troitsk, Russia. 1.- L. Soto, H. Chuaqui, M. Favre, R. Saavedra. E. Wyndham, M. Skowronek, P. Romeas, R. Aliaga-Rossel, and I. Mitchell, IEEE Trans. Plasma Sci. 26, 1179 (1998) 2.- A. Esaulov, P. Sasorov, L. Soto and M. Zambra, ``MHD Simulation of Gas Embedded Plasma Discharge'', submitted for publication. 3.- P. Choi and M. Favre, Rev. Sci. Instrum. 69, 3118, (1998) 4.- C. Moreno, H

  6. The layered structure of the carbon arc discharge plasma

    NASA Astrophysics Data System (ADS)

    Vekselman, Vladislav; Stratton, Brentley; Raitses, Yevgeny; LaboratoryPlasma Nanosynthesis Team

    2016-10-01

    The arc discharge with a consumed anode is commonly used for synthesis of nanomaterials such as fullerenes, nanotubes and, more recently, graphene. The role of the arc plasma in nanosynthesis processes, including ablation of the graphite anode, nucleation and growth of nanostructures remains unclear. Our recent fast frame camera measurements revealed arc oscillations associated with the ablation processes at the anode. More sophisticated measurements using optical emission spectroscopy and spectrally resolved fast framing imaging revealed the complex, layered structure of plasma species distribution, which is dynamically changing. The results of this research include time- and space- resolved distributions of plasma species, plasma electron density and temperature. The obtained experimental data suggest a strong correlation between arc plasma parameters and nanosynthesis processes. This work was supported by US Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division.

  7. Design and Performance Estimates of an Ablative Gallium Electromagnetic Thruster

    NASA Technical Reports Server (NTRS)

    Thomas, Robert E.

    2012-01-01

    The present study details the high-power condensable propellant research being conducted at NASA Glenn Research Center. The gallium electromagnetic thruster is an ablative coaxial accelerator designed to operate at arc discharge currents in the range of 10-25 kA. The thruster is driven by a four-parallel line pulse forming network capable of producing a 250 microsec pulse with a 60 kA amplitude. A torsional-type thrust stand is used to measure the impulse of a coaxial GEM thruster. Tests are conducted in a vacuum chamber 1.5 m in diameter and 4.5 m long with a background pressure of 2 microtorr. Electromagnetic scaling calculations predict a thruster efficiency of 50% at a specific impulse of 2800 seconds.

  8. Capillary forces between chemically different substrates.

    PubMed

    De Souza, E J; Brinkmann, M; Mohrdieck, C; Crosby, A; Arzt, E

    2008-09-16

    Motivated by experimental results, we present numerical and analytical calculations of the capillary force exerted by a capillary bridge spanning the gap between two parallel flat plates of asymmetric wettability. Depending on whether the sum of the two contact angles is smaller or larger than 180 degrees, the capillary force is either attractive or repulsive at small separations D between the plates. In either cases the magnitude of the force diverges as D approaches zero. The leading order of this divergence is captured by an analytical expression deduced from the geometry of the meniscus of a flat capillary bridge. The results for substrates with different wettability reveal an interesting behavior: with the sum of the contact angles fixed, the magnitude of the capillary force and the rupture separation decreases as the asymmetry in contact angles is increased. In addition, we present the rupture separation, i.e., the maximal extension of a capillary bridge, as a function of the contact angles. Our results provide an extensive picture of surface wettability effects on capillary adhesion.

  9. Towards new applications using capillary waveguides

    PubMed Central

    Stasio, Nicolino; Shibukawa, Atsushi; Papadopoulos, Ioannis N.; Farahi, Salma; Simandoux, Olivier; Huignard, Jean-Pierre; Bossy, Emmanuel; Moser, Christophe; Psaltis, Demetri

    2015-01-01

    In this paper we demonstrate the enhancement of the sensing capabilities of glass capillaries. We exploit their properties as optical and acoustic waveguides to transform them potentially into high resolution minimally invasive endoscopic devices. We show two possible applications of silica capillary waveguides demonstrating fluorescence and optical-resolution photoacoustic imaging using a single 330 μm-thick silica capillary. A nanosecond pulsed laser is focused and scanned in front of a capillary by digital phase conjugation through the silica annular ring of the capillary, used as an optical waveguide. We demonstrate optical-resolution photoacoustic images of a 30 μm-thick nylon thread using the water-filled core of the same capillary as an acoustic waveguide, resulting in a fully passive endoscopic device. Moreover, fluorescence images of 1.5 μm beads are obtained collecting the fluorescence signal through the optical waveguide. This kind of silica-capillary waveguide together with wavefront shaping techniques such as digital phase conjugation, paves the way to minimally invasive multi-modal endoscopy. PMID:26713182

  10. Pulsed infrared laser ablation and clinical applications

    NASA Astrophysics Data System (ADS)

    Chan, Kin Foong

    Sufficient light energy deposited in tissue can result in ablation and excessive thermal and mechanical damage to adjacent tissues. The goals of this research are to investigate the mechanisms of pulsed infrared laser ablation of tissue, to optimize laser parameters for minimizing unnecessary damage to healthy tissue, and to explore the potential of using pulsed infrared lasers for clinical applications, especially laser lithotripsy. A dual-channel optical low coherence reflectometer was implemented to measure the expansion and collapse velocities of a Q-switched Ho:YAG (λ = 2.12 μm) laser-induced cavitation in water. Cavitation wall velocities up to 11 m/s were measured with this technique, and the results were in fair agreement with those calculated from fast-flash photographic images. The dependence of ablation threshold fluence on calculus absorption was examined. Preliminary results indicated that the product of optical absorption and ablation threshold fluence, which is the heat of ablation, remained constant for a given urinary calculus type and laser pulse duration. An extended study examined the influence of optical absorption on pulsed infrared laser ablation. An analytical photothermal ablation model was applied and compared to experimental ablation results using an infrared free-electron laser at selected wavelengths between 2.12 μm and 6.45 μm Results were in good agreement with the model, and the ablation depths of urinary calculi were highly dependent upon the calculus optical absorption as well as light attenuation within the intrapulse ablation plume. An efficient wavelength for ablation corresponded to the wavelength of the Er:YAG laser (λ = 2.94 μm) suggested this laser should be examined for laser lithotripsy. Schlieren flash photography, acoustic transient measurements with a piezoelectric polyvinylidene-fluoride needle-hydrophone, mass loss measurements, and chemical analyses were employed to study the ablation mechanisms of the free

  11. Breast radiation - discharge

    MedlinePlus

    Radiation - breast - discharge ... away around 4 to 6 weeks after the radiation treatment is over. You may notice changes in ... breast looks or feels (if you are getting radiation after a lumpectomy). These changes include: Soreness or ...

  12. Brain radiation - discharge

    MedlinePlus

    Radiation - brain - discharge; Cancer-brain radiation; Lymphoma - brain radiation; Leukemia - brain radiation ... Decadron) while you are getting radiation to the brain. It may make you hungrier, cause leg swelling ...

  13. Heart failure - discharge

    MedlinePlus

    ... Heart failure - overview Heart pacemaker High blood pressure Implantable cardioverter-defibrillator Smoking - tips on how to quit ... ask your doctor How to read food labels Implantable cardioverter defibrillator - discharge Low-salt diet Mediterranean diet ...

  14. Concussion - child - discharge

    MedlinePlus

    ... this page: //medlineplus.gov/ency/patientinstructions/000125.htm Concussion in children - discharge To use the sharing features ... enable JavaScript. Your child was treated for a concussion . This is a mild brain injury that can ...

  15. Capacitor discharge pulse analysis.

    SciTech Connect

    Baker, Michael Sean; Griffiths, Stewart K.; Tanner, Danelle Mary

    2013-08-01

    Capacitors used in firing sets and other high discharge current applications are discharge tested to verify performance of the capacitor against the application requirements. Parameters such as capacitance, inductance, rise time, pulse width, peak current and current reversal must be verified to ensure that the capacitor will meet the application needs. This report summarizes an analysis performed on the discharge current data to extract these parameters by fitting a second-order system model to the discharge data and using this fit to determine the resulting performance metrics. Details of the theory and implementation are presented. Using the best-fit second-order system model to extract these metrics results in less sensitivity to noise in the measured data and allows for direct extraction of the total series resistance, inductance, and capacitance.

  16. Multiple sclerosis - discharge

    MedlinePlus

    ... this page: //medlineplus.gov/ency/patientinstructions/000129.htm Multiple sclerosis - discharge To use the sharing features on this ... Your doctor has told you that you have multiple sclerosis (MS). This disease affects the brain and spinal ...

  17. Uterine artery embolization - discharge

    MedlinePlus

    ... page: //medlineplus.gov/ency/patientinstructions/000161.htm Uterine artery embolization - discharge To use the sharing features on this page, please enable JavaScript. You had uterine artery embolization (UAE). UAE is a procedure to treat ...

  18. Deep vein thrombosis - discharge

    MedlinePlus

    ... this page: //medlineplus.gov/ency/patientinstructions/000027.htm Deep vein thrombosis - discharge To use the sharing features ... page, please enable JavaScript. You were treated for deep vein thrombosis ( DVT ). This is a condition in ...

  19. Knee arthroscopy - discharge

    MedlinePlus

    ... remove it. Torn or damaged anterior cruciate ligament (ACL) or posterior cruciate ligament (PCL) Inflamed or damaged ... surgery Knee pain Meniscal allograft transplantation Patient Instructions ACL reconstruction - discharge Getting your home ready - knee or ...

  20. Corneal transplant - discharge

    MedlinePlus

    ... page: //medlineplus.gov/ency/patientinstructions/000243.htm Corneal transplant - discharge To use the sharing features on this page, please enable JavaScript. You had a corneal transplant. Most of the tissue of your cornea (the ...

  1. Shoulder replacement - discharge

    MedlinePlus

    ... page: //medlineplus.gov/ency/patientinstructions/000178.htm Shoulder replacement - discharge To use the sharing features on this page, please enable JavaScript. You had shoulder replacement surgery to replace the bones of your shoulder ...

  2. Electric discharge during electrosurgery

    PubMed Central

    Shashurin, Alexey; Scott, David; Zhuang, Taisen; Canady, Jerome; Beilis, Isak I.; Keidar, Michael

    2015-01-01

    Electric discharge utilized for electrosurgery is studied by means of a recently developed method for the diagnostics of small-size atmospheric plasma objects based on Rayleigh scattering of microwaves on the plasma volume. Evolution of the plasma parameters in the near-electrode sheaths and in the positive column is measured and analyzed. It is found that the electrosurgical system produces a glow discharge of alternating current with strongly contracted positive column with current densities reaching 103 A/cm2. The plasma electron density and electrical conductivities in the channel were found be 1016 cm−3 and (1-2) Ohm−1cm−1, respectively. The discharge interrupts every instance when the discharge-driving AC voltage crosses zero and re-ignites again every next half-wave at the moment when the instant voltage exceeds the breakdown threshold. PMID:25880721

  3. Oil Discharge Reporting Requirements

    EPA Pesticide Factsheets

    If a facility or vessel discharges oil to navigable waters or adjoining shorelines, the owner/operator is required to follow certain federal reporting requirements. This fact sheet outlines those reporting requirements.

  4. Femur fracture repair - discharge

    MedlinePlus

    ... page: //medlineplus.gov/ency/patientinstructions/000166.htm Femur fracture repair - discharge To use the sharing features on this page, please enable JavaScript. You had a fracture (break) in the femur in your leg. It ...

  5. Crohn disease - discharge

    MedlinePlus

    ... diet Nasogastric feeding tube Small bowel resection - discharge Review Date 12/2/2014 Updated by: Jenifer K. ... Frankford-Torresdale Hospital, Aria Health System, Philadelphia, PA. Review provided by VeriMed Healthcare Network. Also reviewed by ...

  6. Cosmetic breast surgery - discharge

    MedlinePlus

    ... this page: //medlineplus.gov/ency/patientinstructions/000273.htm Cosmetic breast surgery - discharge To use the sharing features on this page, please enable JavaScript. You had cosmetic breast surgery to change the size or shape ...

  7. Shoulder surgery - discharge

    MedlinePlus

    ... this page: //medlineplus.gov/ency/patientinstructions/000179.htm Shoulder surgery - discharge To use the sharing features on this page, please enable JavaScript. You had shoulder surgery to repair the tissues inside or around ...

  8. Pneumonia - children - discharge

    MedlinePlus

    ... this page: //medlineplus.gov/ency/patientinstructions/000011.htm Pneumonia in children - discharge To use the sharing features ... this page, please enable JavaScript. Your child has pneumonia, which is an infection in the lungs. In ...

  9. Oral anticoagulant therapy for stroke prevention in patients with atrial fibrillation undergoing ablation: results from the First European Snapshot Survey on Procedural Routines for Atrial Fibrillation Ablation (ESS-PRAFA).

    PubMed

    Potpara, Tatjana S; Larsen, Torben B; Deharo, Jean Claude; Rossvoll, Ole; Dagres, Nikolaos; Todd, Derick; Pison, Laurent; Proclemer, Alessandro; Purefellner, Helmut; Blomström-Lundqvist, Carina

    2015-06-01

    The European Snapshot Survey on Procedural Routines in Atrial Fibrillation Ablation (ESS-PRAFA) is a prospective, multicentre snapshot survey of patients undergoing atrial fibrillation (AF) ablation, conducted to collect patient-based data on current clinical practices in AF ablation in context of the latest AF Guidelines and contemporary oral anticoagulant therapies. The EP Research Network Centres were asked to prospectively enrol consecutive patients during a 6-week period (September/October 2014). Data were collected via the web-based case report form. We present the results pertinent to the use of antithrombotic therapies. Thirteen countries prospectively enrolled 455 eligible consecutive patients [mean age 59 ± 10.8 years, 131 (28.8%) females]. The mean CHA2DS2-VASc score was 1.12 ± 1.06 [137 patients (30.1%) had a score of ≥2]. Before ablation, 443 patients (97.4%) were on anticoagulant therapy [143 (31.4%) on non-vitamin K antagonist oral anticoagulants (NOACs) and 264 (58.0%) on vitamin K antagonists (VKAs)]. Of the latter, 79.7% underwent ablation without VKA interruption, whilst a variety of strategies were used in patients taking NOAC. After ablation, most patients (89.3%) continued the same anticoagulant as before, and 2 (0.4%) were not prescribed any anticoagulation. At discharge, 280 patients (62.2%) were advised oral anticoagulation for a limited period of mean 3.8 ± 2.2 months. On multivariate analysis, CHA2DS2-VASc, AF duration, prior VKA use, and estimated AF ablation success were significantly associated with the decision on short-term anticoagulation. Our results show the increasing use of NOAC in patients undergoing AF ablation and emphasize the need for more information to guide the periprocedural use of both NOACs and VKAs in real-world setting.

  10. Identifying discharge practice training needs.

    PubMed

    Lees, L; Emmerson, K

    A training needs analysis tool was developed to identify nurses' discharge training needs and to improve discharge practice. The tool includes 49 elements of discharge practice subdivided into four areas: corporate, operational, clinical and nurse-led discharge. The tool was disseminated to 15 wards on two hospital sites with assistance from the practice development team. Analysis of discharge training is important to assess discharge training needs and to identify staff who may assist with training.

  11. Micromechanism linear actuator with capillary force sealing

    DOEpatents

    Sniegowski, Jeffry J.

    1997-01-01

    A class of micromachine linear actuators whose function is based on gas driven pistons in which capillary forces are used to seal the gas behind the piston. The capillary forces also increase the amount of force transmitted from the gas pressure to the piston. In a major subclass of such devices, the gas bubble is produced by thermal vaporization of a working fluid. Because of their dependence on capillary forces for sealing, such devices are only practical on the sub-mm size scale, but in that regime they produce very large force times distance (total work) values.

  12. Capillary electrophoresis with indirect amperometric detection.

    PubMed

    Olefirowicz, T M; Ewing, A G

    1990-01-19

    The use of indirect amperometric detection with capillary electrophoresis is demonstrated. The system consists of a porous glass coupler which allows amperometric detection at a carbon fiber electrode placed in the end of the capillary. 3,4-Dihydroxybenzylamine is added to the buffer system as a continuously eluting electrophore. Indirect amperometric detection in 9-mumol I.D. capillaries provides detection limits as low as 380 attomole for the amino acid arginine. Finally, both direct and indirect amperometric detection can be accomplished simultaneously.

  13. Model of a stationary microwave argon discharge at atmospheric pressure

    SciTech Connect

    Zhelyazkov, I.; Pencheva, M.; Benova, E.

    2008-03-19

    The many applications of microwave gas discharges at atmospheric pressure in various fields of science, technology and medicine require an adequate model of these discharges. Such a model is based on the electromagnetic wave's propagation properties and on the elementary processes in the discharge bulk. In contrast to the microwave discharges at low-gas pressures, where many elementary processes might be ignored because of their negligible contribution to the electron and heavy particle's balance equations, for such discharges at atmospheric pressure the consideration of a large number of collisional processes is mandatory. For the build of a successful discharge-column model one needs three important quantities, notably the power {theta} necessary for sustaining an electron - ion pair, electron - neutral collision frequency for momentum transfer v{sub en}, and gas temperature T{sub g}. The first two key parameters are obtained by a collisional-radiative model of the argon at atmospheric pressure, while the microwave frequency {omega}/2{pi} = 2.45 GHz, plasma column radius R, gas pressure p and gas temperature T{sub g} are fixed external parameters determined by the experimental conditions. Here, we present a model of a capillary argon microwave plasma column with a length L {approx_equal} 14 cm, sustained by wave power of 110 W - the model yields the longitudinal distributions of the plasma density, expended wave power, wave electric field magnitude, and complex wave number.

  14. An optical fiber viscometer based on long-period fiber grating technology and capillary tube mechanism.

    PubMed

    Wang, Jian-Neng; Tang, Jaw-Luen

    2010-01-01

    This work addresses the development and assessment of a fiber optical viscometer using a simple and low-cost long-period fiber grating (LPFG) level sensor and a capillary tube mechanism. Previous studies of optical viscosity sensors were conducted by using different optical sensing methods. The proposed optical viscometer consists of an LPFG sensor, a temperature-controlled chamber, and a cone-shaped reservoir where gravitational force could cause fluid to flow through the capillary tube. We focused on the use of LPFGs as level sensors and the wavelength shifts were not used to quantify the viscosity values of asphalt binders. When the LPFG sensor was immersed in the constant volume (100 mL) AC-20 asphalt binder, a wavelength shift was observed and acquired using LabVIEW software and GPIB controller. The time spent between empty and 100 mL was calculated to determine the discharge time. We simultaneously measured the LPFG-induced discharge time and the transmission spectra both in hot air and AC-20 asphalt binder at five different temperatures, 60, 80, 100, 135, and 170 Celsius. An electromechanical rotational viscometer was also used to measure the viscosities, 0.15-213.80 Pa·s, of the same asphalt binder at the above five temperatures. A non-linear regression analysis was performed to convert LPFG-induced discharge time into viscosities. Comparative analysis shows that the LPFG-induced discharge time agreed well with the viscosities obtained from the rotational viscometer.

  15. Intracardiac rhabdomyomas producing symptoms in infancy: the role of radiofrequency catheter ablation

    PubMed Central

    Emmel, M.; Brockmeier, K.; Sreeram, N.

    2006-01-01

    Background Cardiac rhabdomyomas, although benign, may produce symptoms related to arrhythmia or mechanical obstruction. Surgical excision is the therapy of choice for symptomatic rhabdomyomas in infancy. Patients and Methods Two infants with intracardiac rhabdomyomas producing symptoms underwent radiofrequency catheter ablation of the tumour. In patient 1 the diagnosis of multiple rhabdomyomas associated with recurrent supraventricular tachyarrhythmias and foetal hydrops was made in utero. After birth, several antiarrhythmic agents were administered, without successful suppression of the tachyarrhythmia. At seven months of age, the infant had one large residual tumour on the left atrial aspect of the anterior mitral valve leaflet with associated pre-excitation and re-entrant supraventricular tachyarrhythmia suggestive of a left-sided pathway. Catheter ablation of the accessory pathway was performed via a retrograde femoral arterial approach, targeting the earliest site of ventricular activation. Patient 2 presented as a neonate with multiple rhabdomyomas, one of which, measuring 15 mm × 15 mm, was producing severe mitral valve inflow obstruction resulting in symptoms of heart failure due to a large left-to-right shunt at atrial level and persistent pulmonary hypertension. Via the femoral vein, a 5F ablation catheter was advanced across the atrial septum, and the tumour directly ablated. Results Echocardiography performed 24 hours later demonstrated alteration in tumour morphology, with the development of a large central echolucent area, followed by progressive tumour shrinkage in both infants. Patient 1 was discharged at 24 hours, and patient 2 at seven days post-ablation, without symptoms. Follow-up at four weeks confirmed further tumour shrinkage. Conclusion Transcatheter tumour ablation may be beneficial in selected infants and children. ImagesFigure 2AFigure 2BFigure 2CFigure 3AFigure 3BFigure 3C PMID:25696636

  16. On the Ablation Models of Fuel Pellets

    SciTech Connect

    Rozhansky, V.A.; Senichenkov, I.Yu.

    2005-12-15

    The neutral gas shielding model and neutral-gas-plasma shielding model are analyzed qualitatively. The main physical processes that govern the formation of the shielding gas cloud and, consequently, the ablation rate are considered. For the neutral gas shielding model, simple formulas relating the ablation rate and cloud parameters to the parameters of the pellet and the background plasma are presented. The estimates of the efficiency of neutral gas shielding and plasma shielding are compared. It is shown that the main portion of the energy flux of the background electrons is released in the plasma cloud. Formulas for the ablation rate and plasma parameters are derived in the neutral-gas-plasma shielding model. The question is discussed as to why the neutral gas shielding model describes well the ablation rate of the pellet material, although it does not take into account the ionization effects and the effects associated with the interaction of ionized particles with the magnetic field. The reason is that the ablation rate depends weakly on the energy flux of hot electrons; as a result, the attenuation of this flux by the electrostatic shielding and plasma shielding has little effect on the ablation rate. This justifies the use of the neutral gas shielding model to estimate the ablation rate (to within a factor of about 2) over a wide range of parameters of the pellet and the background plasma.

  17. Analysis of infrared laser tissue ablation

    NASA Astrophysics Data System (ADS)

    McKenzie, Gordon P.; Timmerman, Brenda H.; Bryanston-Cross, Peter J.

    2005-04-01

    The mechanisms involved in infrared laser tissue ablation are studied using a free electron laser (FELIX) in order to clarify whether the increased ablation efficiency reported in literature for certain infrared wavelengths is due to a wavelength effect or to the specific pulse structure of the lasers that are generally used in these studies. Investigations are presented of ablation of vitreous from pigs" eyes using several techniques including protein gel electrophoresis and ablation plume visualization. The ablation effects of three different infrared wavelengths are compared: 3 mm, which is currently in clinical surgical use, and the wavelengths associated with the amide I and amide II bands, i.e. 6.2 mm and 6.45mm, respectively. The results suggest a different ablation mechanism to be in operation for each studied wavelength, thus indicating that the generally reported increased ablation efficiency in the 6-6.5 micron range is due to the wavelength rather than the typical free electron laser pulse structure.

  18. Thermal therapy, Part III: ablation techniques.

    PubMed

    Habash, Riadh W Y; Bansal, Rajeev; Krewski, Daniel; Alhafid, Hafid T

    2007-01-01

    Ablative treatments are gaining increasing attention as an alternative to standard surgical therapies, especially for patients with contraindication or those who refuse open surgery. Thermal ablation is used in clinical applications mainly for treating heart arrhythmias, benign prostate hyperplasia, and nonoperable liver tumors; there is also increasing application to other organ sites, including the kidney, lung, and brain. Potential benefits of thermal ablation include reduced morbidity and mortality in comparison with standard surgical resection and the ability to treat nonsurgical patients. The purpose of this review is to outline and discuss the engineering principles and biological responses by which thermal ablation techniques can provide elevation of temperature in organs within the human body. Because of the individual problems associated with each type of treatment, a wide range of ablation techniques have evolved including cryoablation as well as ultrasound, radiofrequency (RF), microwave, and laser ablation. Aspects of each ablation technique, including mechanisms of action, equipment required, selection of eligible patients, treatment techniques, and patient outcomes are presented, along with a discussion of limitations of the techniques and future research directions.

  19. Analytical potential of enzyme-coated capillary reactors in capillary zone electrophoresis.

    PubMed

    Simonet, Bartolomé M; Ríos, Angel; Valcárcel, Miguel

    2004-01-01

    Enzymes immobilized on the inner surface of an electrophoretic capillary were used to increase sensitivity and resolution in capillary zone electrophoresis (CZE). Sensitivity is enhanced by inserting a piece of capillary containing the immobilized enzyme into the main capillary, located before the detector, in order to transform the analyte into a product with a higher absorptivity. This approach was used to determine ethanol. In order to improve resolution, capillary pieces containing immobilized enzymes were inserted at various strategic positions along the electrophoretic capillary. On reaching the enzyme, the analyte was converted into a product with a high electrophoretic mobility, the migration time for which was a function of the position of the enzyme reactor. This approach was applied to the separation and determination of acetaldehyde and pyruvate. Finally, the proposed method was validated with the determination of ethanol, acetaldehyde, and pyruvate in beer and wine samples.

  20. Frequency and Risk Factors of Various Complications After Computed Tomography-Guided Radiofrequency Ablation of Lung Tumors

    SciTech Connect

    Okuma, Tomohisa Matsuoka, Toshiyuki; Yamamoto, Akira; Oyama, Yoshimasa; Toyoshima, Masami; Nakamura, Kenji; Inoue, Yuichi

    2008-01-15

    Objective. To retrospectively determine the frequency and risk factors of various side effects and complications after percutaneous computed tomography-guided radiofrequency (RF) ablation of lung tumors. Methods. We reviewed and analyzed records of 112 treatment sessions in 57 of our patients (45 men and 12 women) with unresectable lung tumors treated by ablation. Risk factors, including sex, age, tumor diameter, tumor location, history of surgery, presence of pulmonary emphysema, electrode gauge, array diameter, patient position, maximum power output, ablation time, and minimum impedance during ablation, were analyzed using univariate and multivariate analyses. Results. Total rates of side effects and minor and major complications occurred in 17%, 50%, and 8% of treatment sessions, respectively. Side effects, including pain during ablation (46% of sessions) and pleural effusion (13% of sessions), occurred with RF ablation. Minor complications, including pneumothorax not requiring chest tube drainage (30% of sessions), subcutaneous emphysema (16% of sessions), and hemoptysis (9% of sessions) also occurred after the procedure. Regarding major complications, three patients developed fever >38.5 deg. C; three patients developed abscesses; two patients developed pneumothorax requiring chest tube insertion; and one patient had air embolism and was discharged without neurologic deficit. Univariate and multivariate analyses suggested that a lesion located {<=}1 cm of the chest wall was significantly related to pain (p < 0.01, hazard index 5.76). Risk factors for pneumothorax increased significantly with previous pulmonary surgery (p < 0.05, hazard index 6.1) and presence of emphysema (p <0.01, hazard index 13.6). Conclusion. The total complication rate for all treatment sessions was 58%, and 25% of patients did not have any complications after RF ablation. Although major complications can occur, RF ablation of lung tumors can be considered a safe and minimally invasive

  1. Thermal protection system ablation sensor

    NASA Technical Reports Server (NTRS)

    Gorbunov, Sergey (Inventor); Martinez, Edward R. (Inventor); Scott, James B. (Inventor); Oishi, Tomomi (Inventor); Fu, Johnny (Inventor); Mach, Joseph G. (Inventor); Santos, Jose B. (Inventor)

    2011-01-01

    An isotherm sensor tracks space vehicle temperatures by a thermal protection system (TPS) material during vehicle re-entry as a function of time, and surface recession through calibration, calculation, analysis and exposed surface modeling. Sensor design includes: two resistive conductors, wound around a tube, with a first end of each conductor connected to a constant current source, and second ends electrically insulated from each other by a selected material that becomes an electrically conductive char at higher temperatures to thereby complete an electrical circuit. The sensor conductors become shorter as ablation proceeds and reduced resistance in the completed electrical circuit (proportional to conductor length) is continually monitored, using measured end-to-end voltage change or current in the circuit. Thermocouple and/or piezoelectric measurements provide consistency checks on local temperatures.

  2. Radiofrequency Ablation: A Nursing Perspective

    PubMed Central

    Locklin, Julia K.; Wood, Bradford J.

    2008-01-01

    Radiofrequency ablation (RFA) has emerged as a safe and predictable technology for treating certain patients with cancer who otherwise have few treatment options. Nurses need to be familiar with all phases of the RFA procedure to create an optimal environment for patients. This article offers a brief review of the RFA procedure and nurses' responsibilities in caring for these patients. Before RFA, nurses should focus on patient education and aggressive hydration. During the procedure, nurses can prevent injury by placing grounding pads appropriately, monitoring vital signs, and medicating patients as needed. After RFA, nurses should assess the skin puncture site, provide adequate pain relief, and, again, hydrate patients. Nurses who care appropriately for RFA recipients may help to improve patient outcomes and make an otherwise frightening procedure more comfortable. PMID:15973845

  3. Ablation of idiopathic ventricular tachycardia.

    PubMed

    Schreiber, Doreen; Kottkamp, Hans

    2010-09-01

    Idiopathic ventricular arrhythmias occur in patients without structural heart disease. They can arise from a variety of specific areas within both ventricles and in the supravalvular regions of the great arteries. Two main groups need to be differentiated: arrhythmias from the outflow tract (OT) region and idiopathic left ventricular, so-called fascicular, tachycardias (ILVTs). OT tachycardia typically originates in the right ventricular OT, but may also occur in the left ventricular OT, particularly in the sinuses of Valsalva or the anterior epicardium or the great cardiac vein. Activation mapping or pace mapping for the OT regions and mapping of diastolic potentials in ILVTs are the mapping techniques that are typically used. The ablation of idiopathic ventricular arrhythmias is highly successful, associated with only rare complications. Newly recognized entities of idiopathic ventricular tachycardias are those originating in the papillary muscles and in the atrioventricular annular regions.

  4. High Q silica microbubble resonators fabricated by arc discharge

    NASA Astrophysics Data System (ADS)

    Berneschi, S.; Farnesi, D.; Cosi, F.; Nunzi Conti, G.; Pelli, S.; Righini, G. C.; Soria, S.

    2011-09-01

    Microbubble resonators combine the unique properties of whispering gallery mode resonators with the intrinsic capability of integrated microfluidics. Here an improved fabrication method of microbubble resonators is presented, based on the heating of a slightly pressurized capillary by a rotating arc discharge. Rotation of the electrodes, moved out of a fiber splicer, ensures a homogeneous distribution of the heat all over the capillary surface. The demonstrated microbubble resonators have Q factors up to 6×107 at 1550nm. Microbubbles were filled with water and aqueous solutions of ethanol in order to test the refractive index sensing capabilities of such resonators, which also show a good temporal stability. The limit of detection of our microbubble resonator sensor is 10-6RIU.

  5. High Q silica microbubble resonators fabricated by arc discharge.

    PubMed

    Berneschi, S; Farnesi, D; Cosi, F; Conti, G Nunzi; Pelli, S; Righini, G C; Soria, S

    2011-09-01

    Microbubble resonators combine the unique properties of whispering gallery mode resonators with the intrinsic capability of integrated microfluidics. Here an improved fabrication method of microbubble resonators is presented, based on the heating of a slightly pressurized capillary by a rotating arc discharge. Rotation of the electrodes, moved out of a fiber splicer, ensures a homogeneous distribution of the heat all over the capillary surface. The demonstrated microbubble resonators have Q factors up to 6×10(7) at 1550 nm. Microbubbles were filled with water and aqueous solutions of ethanol in order to test the refractive index sensing capabilities of such resonators, which also show a good temporal stability. The limit of detection of our microbubble resonator sensor is 10(-6) RIU.

  6. Nanosecond laser ablation of gold nanoparticle films

    SciTech Connect

    Ko, Seung H.; Choi, Yeonho; Hwang, David J.; Grigoropoulos, Costas P.; Chung, Jaewon; Poulikakos, Dimos

    2006-10-02

    Ablation of self-assembled monolayer protected gold nanoparticle films on polyimide was explored using a nanosecond laser. When the nanoparticle film was ablated and subsequently thermally sintered to a continuous film, the elevated rim structure by the expulsion of molten pool could be avoided and the ablation threshold fluence was reduced to a value at least ten times lower than the reported threshold for the gold film. This could be explained by the unusual properties of nanoparticle film such as low melting temperature, weak bonding between nanoparticles, efficient laser energy deposition, and reduced heat loss. Finally, submicron lines were demonstrated.

  7. IR laser ablation of dental enamel

    NASA Astrophysics Data System (ADS)

    Fried, Daniel

    2000-03-01

    An overview of the basic mechanisms of IR laser ablation of dental enamel is presented. Enamel is a highly structured tissue consisting of an heterogeneous distribution of water, mineral, protein and lipid. Absorption bands of water and carbonated hydroxyapatite can be selectively targeted from 2.7 to 11-micrometer via several laser wavelengths. Mechanistic differences in the nature of ablation and the varying surface morphology produced can be explained by the microstructure of the tissue. Suggested criteria for the choice of the optimum laser parameters for clinical use, the influence of plasma shielding and the role of exogenous water on the mechanism of ablation are discussed.

  8. Diamond Ablators for Inertial Confinement Fusion

    SciTech Connect

    Biener, J; Mirkarimi, P B; Tringe, J W; Baker, S L; Wang, Y M; Kucheyev, S O; Teslich, N E; Wu, K J; Hamza, A V; Wild, C; Woerner, E; Koidl, P; Bruehne, K; Fecht, H

    2005-06-21

    Diamond has a unique combination of physical properties for the inertial confinement fusion ablator application, such as appropriate optical properties, high atomic density, high yield strength, and high thermal conductivity. Here, we present a feasible concept to fabricate diamond ablator shells. The fabrication of diamond capsules is a multi-step process, which involves diamond chemical vapor deposition on silicon mandrels followed by polishing, microfabrication of holes, and removing of the silicon mandrel by an etch process. We also discuss the pros and cons of coarse-grained optical quality and nanocrystalline chemical vapor deposition diamond films for the ablator application.

  9. Radiofrequency Ablation of Persistent Atrial Fibrillation

    PubMed Central

    Hussein, Ayman A.; Saliba, Walid I.; Barakat, Amr; Bassiouny, Mohammed; Chamsi-Pasha, Mohammed; Al-Bawardy, Rasha; Hakim, Ali; Tarakji, Khaldoun; Baranowski, Bryan; Cantillon, Daniel; Dresing, Thomas; Tchou, Patrick; Martin, David O.; Varma, Niraj; Bhargava, Mandeep; Callahan, Thomas; Niebauer, Mark; Kanj, Mohamed; Chung, Mina; Natale, Andrea; Lindsay, Bruce D.; Wazni, Oussama M.

    2017-01-01

    Background Various ablation strategies of persistent atrial fibrillation (PersAF) have had disappointing outcomes, despite concerted clinical and research efforts, which could reflect progressive atrial fibrillation–related atrial remodeling. Methods and Results Two-year outcomes were assessed in 1241 consecutive patients undergoing first-time ablation of PersAF (2005–2012). The time intervals between the first diagnosis of PersAF and the ablation procedures were determined. Patients had echocardiograms and measures of B-type natriuretic peptide and C-reactive protein before the procedures. The median diagnosis-to-ablation time was 3 years (25th–75th percentiles 1–6.5). With longer diagnosis-to-ablation time (based on quartiles), there was a significant increase in recurrence rates in addition to an increase in B-type natriuretic peptide levels (P=0.01), C-reactive protein levels (P<0.0001), and left atrial size (P=0.03). The arrhythmia recurrence rates over 2 years were 33.6%, 52.6%, 57.1%, and 54.6% in the first, second, third, and fourth quartiles, respectively (Pcategorical<0.0001). In Cox Proportional Hazard analyses, B-type natriuretic peptide levels, C-reactive protein levels, and left atrial size were associated with arrhythmia recurrence. The diagnosis-to-ablation time had the strongest association with the ablation outcomes which persisted in multivariable Cox analyzes (hazard ratio for recurrence per +1Log diagnosis-to-ablation time 1.27, 95% confidence interval 1.14–1.43; P<0.0001; hazard ratio fourth versus first quartile 2.44, 95% confidence interval 1.68–3.65; Pcategorical<0.0001). Conclusions In patients with PersAF undergoing ablation, the time interval between the first diagnosis of PersAF and the catheter ablation procedure had a strong association with the ablation outcomes, such as shorter diagnosis-to-ablation times were associated with better outcomes and in direct association with markers of atrial remodeling. PMID:26763227

  10. Ablation of pulmonary malignancy: current status.

    PubMed

    Pua, Bradley B; Thornton, Raymond H; Solomon, Stephen B

    2010-08-01

    Since the first reported use of radiofrequency ablation of the lung in 2000, the field of image-guided lung ablation has received a considerable amount of attention. Survival studies have demonstrated the potential utility of thermal ablation in the treatment of patients with early-stage primary and limited secondary pulmonary tumors with promising results. Diagnostic imaging studies have advanced the understanding of the expected immediate postablation appearance of treated lesions, leading the way for early detection of local tumor progression. These survival studies and the expected imaging follow-up of these patients are reviewed herein.

  11. Applicability of chemically modified capillaries in chiral capillary electrophoresis for methamphetamine profiling.

    PubMed

    Iwata, Yuko T; Mikuma, Toshiyasu; Kuwayama, Kenji; Tsujikawa, Kenji; Miyaguchi, Hajime; Kanamori, Tatsuyuki; Inoue, Hiroyuki

    2013-03-10

    We examined the applicability of chemically modified capillaries on the chiral capillary electrophoresis of essential compounds for methamphetamine (MA) profiling (MA, amphetamine, ephedrine, pseudoephedrine, norephedrine, and norpseudoephedrine) using highly sulfated γ-cyclodextrin as a chiral selector. Four types of chemically modified capillaries, namely, FunCap-CE/Type D (possessing diol groups), Type A (amino groups), Type C (carboxyl groups), and Type S (sulfate groups), were evaluated. Repeatability, speed, and good chiral resolution sufficient for routine MA profiling were achieved with the Type S capillary.

  12. CAPILLARY BARRIERS IN UNSATURATED FRACTURED ROCKS

    SciTech Connect

    Y.S. Wu; W. Zhang; L. Pan; J. Hinds; G. Bodvarsson

    2000-10-01

    This work presents modeling studies investigating the effects of capillary barriers on fluid-flow and tracer-transport processes in the unsaturated zone of Yucca Mountain, Nevada, a potential site for storing high-level radioactive waste. These studies are designed to identify factors controlling the formation of capillary barriers and to estimate their effects on the extent of possible large-scale lateral flow in unsaturated fracture rocks. The modeling approach is based on a continuum formulation of coupled multiphase fluid and tracer transport through fractured porous rock. Flow processes in fractured porous rock are described using a dual-continuum concept. In addition, approximate analytical solutions are developed and used for assessing capillary-barrier effects in fractured rocks. This study indicates that under the current hydrogeologic conceptualization of Yucca Mountain, strong capillary-barrier effects exist for significantly diverting moisture flow.

  13. Multistaged stokes injected Raman capillary waveguide amplifier

    DOEpatents

    Kurnit, Norman A.

    1980-01-01

    A multistaged Stokes injected Raman capillary waveguide amplifier for providing a high gain Stokes output signal. The amplifier uses a plurality of optically coupled capillary waveguide amplifiers and one or more regenerative amplifiers to increase Stokes gain to a level sufficient for power amplification. Power amplification is provided by a multifocused Raman gain cell or a large diameter capillary waveguide. An external source of CO.sub.2 laser radiation can be injected into each of the capillary waveguide amplifier stages to increase Raman gain. Devices for injecting external sources of CO.sub.2 radiation include: dichroic mirrors, prisms, gratings and Ge Brewster plates. Alternatively, the CO.sub.2 input radiation to the first stage can be coupled and amplified between successive stages.

  14. CAPILLARY ELECTROPHORETIC BEHAVIOR OF SEVEN SULFONYLUREAS

    EPA Science Inventory

    The electrophoretic behavior of bensulfuron Me, sulfometuron Me, nicosulfuron (Accent), chlorimuron Et, thifensulfuron Me (Harmony), metsulfuron Me, and chlorsulfuron was studied under capillary zone electrophoresis (CZE) and micellar electrokinetic chromatography (MEKC) conditio...

  15. Characterising Microstructured Materials Using a Capillary Rheometer

    NASA Astrophysics Data System (ADS)

    Hicks, Christopher I.; See, Howard; Arabo, Emad Y. M.

    2008-07-01

    A parallel plate and capillary rheometer have been used to rheologically characterize an Australian hard wheat flour-water dough over an extensive range of shear rates (10-3-104 s-1). Torsional measurements showed that the shear viscosity of dough increased with strain to a maximum value then decreased, suggesting a breakdown of the dough structure. This was consistent with other published data on doughs. Capillary experiments revealed the shear thinning behavior of dough, which was described by a power-law model. The wall slip behavior of dough was examined, revealing a critical shear stress at which slip occurs for a 1 mm diameter capillary. The capillary data was best linked to the torsional data at low strain values (˜0.1) as expected given the nature of sampling in the two rheometers.

  16. ISS Update: Capillary Flow Experiments-2

    NASA Video Gallery

    NASA Public Affairs Officer Kelly Humphries interviews Dr. Mark Weislogel, Principal Investigator for the Capillary Flow Experiments-2 (CFE), from the Portland State University in Oregon. The CFE i...

  17. Cycloaliphatic epoxy resin coating for capillary electrophoresis.

    PubMed

    Shah, Roopa S; Wang, Qinggang; Lee, Milton L

    2002-04-05

    Coating the interior surface of a fused-silica capillary with a polymeric material has long been used in capillary electrophoresis (CE) to reduce or eliminate electroosmotic flow and suppress adsorption. A cycloaliphatic epoxide-based resin was bonded to silane treated capillaries and crosslinked with a curing agent. The epoxy resin coating significantly reduced electroosmotic flow over a pH range of 3-10. This coating was sufficiently hydrophilic to suppress protein adsorption. The epoxy resin coated capillary was used to separate several acidic and basic proteins and peptides. Separation efficiencies greater than 400,000 theoretical plates were achieved. The relative standard deviations in migration times for proteins were <0.8%. Speed and simplicity are important advantages of the coating procedure compared to other published coating methods.

  18. Capillary electrochromatography using fibers as stationary phases.

    PubMed

    Jinno, K; Watanabe, H; Saito, Y; Takeichi, T

    2001-10-01

    Fiber-packed capillary columns have been evaluated in chromatographic performance in capillary electrochromatography (CEC). The change of electroosmotic flow (EOF) velocity and selectivity using different kinds of fiber materials was examined. Although the EOF velocity among the different fiber packed columns was almost the same, retention of parabens was larger on the Kevlar-packed column than on the Zylon-packed one, and was larger on the as-span-type fiber-packed column than on the high-modulus-type packed one. Using 200 microm ID x 5 cm Kevlar packed column combined with a 100 microm ID x 20 cm precolumn capillary and a 530 microm ID x 45 cm postcolumn capillary, the separation of three parabens within 30 s was achieved. Other compounds were also separated in a few minutes by the fiber-packed CEC method.

  19. Unusual intraosseous capillary hemangioma of the mandible.

    PubMed

    Dereci, Omur; Acikalin, Mustafa Fuat; Ay, Sinan

    2015-01-01

    Intraosseous hemangioma is a benign vascular neoplasm, which is mostly seen in vertebrae, maxillofacial bones, and long bones. Intraosseous hemangioma is rarely seen on jaw bones compared to other skeletal bones and usually occurs in the cavernous form. Capillary intraosseous hemangioma of jaws is an uncommon form of intraosseous hemangioma and has not been thoroughly described so far. In this study, a case of capillary intraosseous hemangioma of the mandible was presented with relevant literature review.

  20. Thin film capillary process and apparatus

    DOEpatents

    Yu, Conrad M.

    2003-11-18

    Method and system of forming microfluidic capillaries in a variety of substrate materials. A first layer of a material such as silicon dioxide is applied to a channel etched in substrate. A second, sacrificial layer of a material such as a polymer is deposited on the first layer. A third layer which may be of the same material as the first layer is placed on the second layer. The sacrificial layer is removed to form a smooth walled capillary in the substrate.

  1. Use of a circular mapping and ablation catheter for ablation of atypical right ventricular outflow tract arrhythmia.

    PubMed

    Katritsis, Demosthenes G; Giazitzoglou, Eleftherios; Paxinos, George

    2010-02-01

    A new technique for ablation of persistent ectopic activity with atypical electrocardiographic characteristics at the vicinity of the right ventricular outflow tract is described. A new circular mapping and ablation catheter initially designed for pulmonary vein ablation was used. Abolition of ectopic activity was achieved with minimal fluoroscopy and ablation times.

  2. Lithium granule ablation and penetration during ELM pacing experiments at DIII-D

    SciTech Connect

    Lunsford, R.; Bortolon, A.; Roquemore, A. L.; Mansfield, D. K.; Nagy, A.; Maingi, R.; Parks, P. B.; Jackson, G.; Gilson, E.; Chrobak, C. P.

    2016-05-25

    At DIII-D, lithium granules were radially injected into the plasma at the outer midplane to trigger and pace edge localized modes (ELMs). Granules ranging in size from 300 to 1000 microns were horizontally launched into H-mode discharges with velocities near 100 m/s, and granule to granule injection frequencies less than 500 Hz. While the smaller granules were only successful in triggering ELMs approximately 20% of the time, the larger granules regularly demonstrated ELM triggering efficiencies of greater than 80%. A fast visible camera looking along the axis of injection observed the ablation of the lithium granules. We used the duration of ablation as a benchmark for a neutral gas shielding calculation, and approximated the ablation rate and mass deposition location for the various size granules, using measured edge plasma profiles as inputs. In conclusion, this calculation suggests that the low triggering efficiency of the smaller granules is due to the inability of these granules to traverse the steep edge pressure gradient region and reach the top of the pedestal prior to full ablation.

  3. Lithium granule ablation and penetration during ELM pacing experiments at DIII-D

    DOE PAGES

    Lunsford, R.; Bortolon, A.; Roquemore, A. L.; ...

    2016-05-25

    At DIII-D, lithium granules were radially injected into the plasma at the outer midplane to trigger and pace edge localized modes (ELMs). Granules ranging in size from 300 to 1000 microns were horizontally launched into H-mode discharges with velocities near 100 m/s, and granule to granule injection frequencies less than 500 Hz. While the smaller granules were only successful in triggering ELMs approximately 20% of the time, the larger granules regularly demonstrated ELM triggering efficiencies of greater than 80%. A fast visible camera looking along the axis of injection observed the ablation of the lithium granules. We used the durationmore » of ablation as a benchmark for a neutral gas shielding calculation, and approximated the ablation rate and mass deposition location for the various size granules, using measured edge plasma profiles as inputs. In conclusion, this calculation suggests that the low triggering efficiency of the smaller granules is due to the inability of these granules to traverse the steep edge pressure gradient region and reach the top of the pedestal prior to full ablation.« less

  4. Bundled capillary electrophoresis using microstructured fibres.

    PubMed

    Rogers, Benjamin; Gibson, Graham T T; Oleschuk, Richard D

    2011-01-01

    Joule heating, arising from the electric current passing through the capillary, causes many undesired effects in CE that ultimately result in band broadening. The use of narrow-bore capillaries helps to solve this problem as smaller cross-sectional area results in decreased Joule heating and the rate of heat dissipation is increased by the larger surface-to-volume ratio. Issues arising from such small capillaries, such as poor detection sensitivity, low loading capacity and high flow-induced backpressure (complicating capillary loading) can be avoided by using a bundle of small capillaries operating simultaneously that share buffer reservoirs. Microstructured fibres, originally designed as waveguides in the telecommunication industry, are essentially a bundle of parallel ∼5 μm id channels that extend the length of a fibre having otherwise similar dimensions to conventional CE capillaries. This work presents the use of microstructured fibres for CZE, taking advantage of their relatively high surface-to-volume ratio and the small individual size of each channel to effect highly efficient separations, particularly for dye-labelled peptides.

  5. [Transvascular fluid exchange disturbed by capillary injuries].

    PubMed

    Lugrin, D; Chave, S; Raucoules, M; Grimaud, D

    1996-01-01

    Fluid exchange disorders due to capillary lesions are numerous and their extent depends on the underlying disease as well as the capillary structure of the affected organ. The inflammatory cascade, triggered by sepsis or reperfusion injury, is mediated by several humoral mediators and activated blood cells. These include pro-inflammatory cytokines, arachidonic acid, proteases, oxygen free radicals, polymorphonuclears, procoagulant, complement and fibrinolytic system. The interaction between these mediators leads to a loss of endothelial integrity, a loss of basment membrane and a disruption of the interstitial matrix, with wasting of the endothelial cytoskeleton. The alteration in permeability induces transcapillary exudation of water and protein in the interstitial space, leading to organ dysfunction, mainly the lungs and splanchnic organs. Nitric oxyde, by modulating the response of the endothelium to the cellular interaction may protect against capillary injury. Capillary "stress lesions" following microvascular hypertension are the physiological basis of neurogenic or high altitude pulmonary oedema, and overinflation injury from mechanical ventilation. The anatomic specific features of the cerebral capillaries resulted in the well known concept of blood brain barrier with it's changeing morphology. Under the effect of humoral mediators and cellular interactions, the endothelial cells are able, via a calcium-mediated mechanism, to contract and to modify capillary permeability, leading to vasogenic oedema.

  6. Multiple capillary biochemical analyzer with barrier member

    DOEpatents

    Dovichi, Norman J.; Zhang, Jian Z.

    1996-01-01

    A multiple capillary biochemical analyzer for sequencing DNA and performing other analyses, in which a set of capillaries extends from wells in a microtiter plate into a cuvette. In the cuvette the capillaries are held on fixed closely spaced centers by passing through a sandwich construction having a pair of metal shims which squeeze between them a rubber gasket, forming a leak proof seal for an interior chamber in which the capillary ends are positioned. Sheath fluid enters the chamber and entrains filament sample streams from the capillaries. The filament sample streams, and sheath fluid, flow through aligned holes in a barrier member spaced close to the capillary ends, into a collection chamber having a lower glass window. The filament streams are illuminated above the barrier member by a laser, causing them to fluoresce. The fluorescence is viewed end-on by a CCD camera chip located below the glass window. The arrangement ensures an equal optical path length from all fluorescing spots to the CCD chip and also blocks scattered fluorescence illumination, providing more uniform results and an improved signal to noise ratio.

  7. Multiple capillary biochemical analyzer with barrier member

    DOEpatents

    Dovichi, N.J.; Zhang, J.Z.

    1996-10-22

    A multiple capillary biochemical analyzer is disclosed for sequencing DNA and performing other analyses, in which a set of capillaries extends from wells in a microtiter plate into a cuvette. In the cuvette the capillaries are held on fixed closely spaced centers by passing through a sandwich construction having a pair of metal shims which squeeze between them a rubber gasket, forming a leak proof seal for an interior chamber in which the capillary ends are positioned. Sheath fluid enters the chamber and entrains filament sample streams from the capillaries. The filament sample streams, and sheath fluid, flow through aligned holes in a barrier member spaced close to the capillary ends, into a collection chamber having a lower glass window. The filament streams are illuminated above the barrier member by a laser, causing them to fluoresce. The fluorescence is viewed end-on by a CCD camera chip located below the glass window. The arrangement ensures an equal optical path length from all fluorescing spots to the CCD chip and also blocks scattered fluorescence illumination, providing more uniform results and an improved signal-to-noise ratio. 12 figs.

  8. Capillary breakup of fluid threads within confinement

    NASA Astrophysics Data System (ADS)

    Hu, Guoqing; Xue, Chundong; Chen, Xiaodong

    2016-11-01

    Fluid thread breakup is a widespread phenomenon in nature, industry, and daily life. Driven by surface tension (or capillarity) at low flow-rate condition, the breakup scenario is usually called capillary instability or Plateau-Rayleigh instability. Fluid thread deforms under confinement of ambient fluid to form a fluid neck. Thinning of the neck at low flow-rate condition is quasistatic until the interface becomes unstable and collapses to breakup. Underlying mechanisms and universalities of both the stable and unstable thinning remain, however, unclear and even contradictory. Here we conduct new numerical and experimental studies to show that confined interfaces are not only stabilized but also destabilized by capillarity at low flow-rate condition. Capillary stabilization is attributed to confinement-determined internal pressure that is higher than capillary pressure along the neck. Two origins of capillary destabilization are identified: one is confinement-induced gradient of capillary pressure along the interface; the other is the competition between local capillary pressure and internal pressure. This work was supported by National Natural Science Foundation of China (Grant No. 11402274, 11272321, and 11572334).

  9. OCT methods for capillary velocimetry

    PubMed Central

    Srinivasan, Vivek J.; Radhakrishnan, Harsha; Lo, Eng H.; Mandeville, Emiri T.; Jiang, James Y.; Barry, Scott; Cable, Alex E.

    2012-01-01

    To date, two main categories of OCT techniques have been described for imaging hemodynamics: Doppler OCT and OCT angiography. Doppler OCT can measure axial velocity profiles and flow in arteries and veins, while OCT angiography can determine vascular morphology, tone, and presence or absence of red blood cell (RBC) perfusion. However, neither method can quantify RBC velocity in capillaries, where RBC flow is typically transverse to the probe beam and single-file. Here, we describe new methods that potentially address these limitations. Firstly, we describe a complex-valued OCT signal in terms of a static scattering component, dynamic scattering component, and noise. Secondly, we propose that the time scale of random fluctuations in the dynamic scattering component are related to red blood cell velocity. Analysis was performed along the slow axis of repeated B-scans to parallelize measurements. We correlate our purported velocity measurements against two-photon microscopy measurements of RBC velocity, and investigate changes during hypercapnia. Finally, we image the ischemic stroke penumbra during distal middle cerebral artery occlusion (dMCAO), where OCT velocimetry methods provide additional insight that is not afforded by either Doppler OCT or OCT angiography. PMID:22435106

  10. Flash water-window x-ray generator with a ferrite capillary

    NASA Astrophysics Data System (ADS)

    Sato, Eiichi; Sagae, Michiaki; Ichimaru, Toshio; Takayama, Kazuyoshi; Sakamaki, Kimio; Tamakawa, Yoshiharu

    1997-12-01

    The fundamental study on a flash water-window x-ray generator is described. This generator is composed of a high-voltage power supply, a polarity-inversion high-voltage pulser, a krytron pulser as a trigger device, an oil-diffusion pump, and a vacuum chamber with a capillary. A combined ceramic condenser of about 5 nF in the pulser is charged up to 70 kV by the power supply, and the electric charges in the condenser are discharged to the capillary in the tube after closing a gap switch by the krytron pulser. In the present work, the chamber is evacuated by the pump with a pressure of about 1 by 10-3 Pa, and the titanium anode and cathode electrodes are employed to produce L-series characteristic x rays in the water-window range. The diameter and the length of the ferrite capillary are 2.0 and 30 mm, respectively. Both the cathode voltage and the discharge current displayed damped oscillations. The peak values of the voltage and current increased when the charging voltage was increased, and their maximum values were minus 24 kV and 2.8 kA, respectively. The pulse durations of the water-window x-rays were nearly equivalent to those of the damped oscillations of the voltage and current, and their values were less than 10 microseconds.

  11. Modeling and Simulation of Ablation-Controlled Plasmas

    NASA Astrophysics Data System (ADS)

    Kundrapu, Madhusudhan N.

    Ablation and plasma formation in high energy laser target interactions and arc discharges are studied numerically. Each of the two processes is modeled separately due to the type of energy source and the resulting flow eld. Ablation of the target material and plasma formation are coupled to obtain evaporation rate, temperature distribution, velocity eld, and species concentration self-consistently. Laser ablation is studied in the perspective of directed energy applications, where beam size varies from few centimeters to tens of centimeters with energies extending up to 10 kW/cm2. Because of this high energy deposition, the evaporated material expands to supersonic speeds into the free space. Due to the large spot sizes and associated supersonic flow, one dimensional Euler equations are considered to be sufficient for modeling the plume. Instead, more emphasis was given to evaporation model, by introducing Knudsen layer kinetics at the plume target interface, and plasma shielding. The evaporation rate is validated with results from the experiments and simulations are carried out to nd the in fluence of laser beam frequency on evaporation rates. The evaporation model used in this work is found to be more accurate than the widely used model based on sonic speed assumption. The optimum beam wavelength for Al surfaces is found to be 850 nm. Attenuation of telemetry data by plasma is a concern for the testing of directed energy systems. Electrostatic approach for the mitigation of communication attenuation is analyzed to obtain the fluency limits up to which the approach can be implemented. It is found from sheath calculations that uninterrupted telemetry can be achieved through Al plasma for fluences below 4 J/cm2 at a background pressure of 1 atm, using a maximum bias voltage of 10 kV . Arc discharge ablation is modeled for the synthesis of nanoparticles. The electric arc generated between the electrodes, placed inside a Helium chamber, evaporates the catalyst

  12. Water dissociation in a radio-frequency electromagnetic field with ex situ electrodes—modelling of discharge initiation

    NASA Astrophysics Data System (ADS)

    Schneider, Jens; Holzer, Frank; Rabe, Carsten; Häupl, Tilmann; Kopinke, Frank-Dieter; Roland, Ulf

    2013-04-01

    Applying a new experimental design with a capillary glass reactor and plate electrodes outside of the reactor allowed the initiation of discharges in aqueous electrolytes under the influence of a radio-frequency (RF) electromagnetic field. This study focused on the mechanism leading to the initiation of such discharges in the restriction of a glass tube. The light emission correlated with discharges was analysed with optical emission spectroscopy. Electrons with energies between 20 and 45 eV were responsible for the dissociation of water molecules into (excited) OH, H and O radicals. Current-voltage characteristics were measured before and under discharge conditions. Modelling of the experimental setup and simulation of electrical field strength distribution support the hypothesis of the origin of discharges in general and experimental findings such as ring-shaped discharges and a minimum solution conductivity of about 1 S m-1 required for discharge initiation with RF voltages of 2 kV.

  13. Laser ablation in analytical chemistry - A review

    SciTech Connect

    Russo, Richard E.; Mao, Xianglei; Liu, Haichen; Gonzalez, Jhanis; Mao, Samuel S.

    2001-10-10

    Laser ablation is becoming a dominant technology for direct solid sampling in analytical chemistry. Laser ablation refers to the process in which an intense burst of energy delivered by a short laser pulse is used to sample (remove a portion of) a material. The advantages of laser ablation chemical analysis include direct characterization of solids, no chemical procedures for dissolution, reduced risk of contamination or sample loss, analysis of very small samples not separable for solution analysis, and determination of spatial distributions of elemental composition. This review describes recent research to understand and utilize laser ablation for direct solid sampling, with emphasis on sample introduction to an inductively coupled plasma (ICP). Current research related to contemporary experimental systems, calibration and optimization, and fractionation is discussed, with a summary of applications in several areas.

  14. Nanoscale ablation through optically trapped microspheres

    NASA Astrophysics Data System (ADS)

    Fardel, Romain; McLeod, Euan; Tsai, Yu-Cheng; Arnold, Craig B.

    2010-10-01

    The ability to directly create patterns with size scales below 100 nm is important for many applications where the production or repair of high resolution and density features is needed. Laser-based direct-write methods have the benefit of being able to quickly and easily modify and create structures on existing devices, but ablation can negatively impact the overall technique. In this paper we show that self-positioning of near-field objectives through the optical trap assisted nanopatterning (OTAN) method allows for ablation without harming the objective elements. Small microbeads are positioned in close proximity to a substrate where ablation is initiated. Upon ablation, these beads are temporarily displaced from the trap but rapidly return to the initial position. We analyze the range of fluence values for which this process occurs and find that there exists a critical threshold beyond which the beads are permanently ejected.

  15. Physical processes of laser tissue ablation

    NASA Astrophysics Data System (ADS)

    Furzikov, Nickolay P.

    1991-05-01

    The revised ablation model applicable to homogeneous tissues is presented. It is based on the thermal mechanism and involves the instability of the laserinduced evaporation (thermodestruction) front the growth of the surface ripple structure the interference of the laser wave and of the surface wave arising by diffraction on the ripples Beer''s law violation the pulsed thermodestruction of the organic structural component the tissue water boiling and gas dynamic expansion of the resulting products into the surrounding medium which is followed by the shock wave formation. The UV and IR ablation schemes were implemented and compared to the corneal ablation experiments. The initial ablation pressure and temperature are given restored from the timeofflight measurements of the supersonic expansion of the product. 1.

  16. Evolving Ablative Therapies for Hepatic Malignancy

    PubMed Central

    Hochwald, Steven N.

    2014-01-01

    The liver is a common site for both primary and secondary malignancy. Hepatic resection and transplantation are the two treatment modalities that have been shown to achieve complete cure, but only 10 to 20% of patients are candidates for these treatments. For the remaining patients, tumor ablation has emerged as the most promising alternative modality. In addition to providing local control and improving survival outcomes, tumor ablation also helps to down stage patients for potential curative treatments, both alone as well as in combination with other treatments. While tumor ablation can be achieved in multiple ways, the introduction of newer ablative techniques has shifted the focus from palliation to potentially curative treatment. Because the long-term safety and survival benefits are not substantive at present, it is important that we strive to evaluate the results from these studies using appropriate comparative outcome methodologies. PMID:24877069

  17. Thermal Ablation Modeling for Silicate Materials

    NASA Technical Reports Server (NTRS)

    Chen, Yih-Kanq

    2016-01-01

    A general thermal ablation model for silicates is proposed. The model includes the mass losses through the balance between evaporation and condensation, and through the moving molten layer driven by surface shear force and pressure gradient. This model can be applied in the ablation simulation of the meteoroid and the glassy ablator for spacecraft Thermal Protection Systems. Time-dependent axisymmetric computations are performed by coupling the fluid dynamics code, Data-Parallel Line Relaxation program, with the material response code, Two-dimensional Implicit Thermal Ablation simulation program, to predict the mass lost rates and shape change. The predicted mass loss rates will be compared with available data for model validation, and parametric studies will also be performed for meteoroid earth entry conditions.

  18. Pharmacological Tests in Atrial Fibrillation Ablation

    PubMed Central

    Gourraud, Jean-Baptiste; Andrade, Jason G; Macle, Laurent

    2016-01-01

    The invasive management of atrial fibrillation (AF) has been considerably changed by the identification of major sites of AF initiation and/or maintenance within the pulmonary vein antra. Percutaneous catheter ablation of these targets has become the standard of care for sustained maintenance of sinus rhythm. Long-term failure of ablation is related to an inability to create a durable transmural lesion or to identify all of the non-pulmonary vein arrhythmia triggers. Pharmacological challenges during catheter ablation have been suggested to improve outcomes in both paroxysmal and persistent AF. Herein we review the mechanism and evidence for the use of pharmacological adjuncts during the catheter ablation of AF. PMID:28116081

  19. Microwave Tissue Ablation: Biophysics, Technology and Applications

    PubMed Central

    2010-01-01

    Microwave ablation is an emerging treatment option for many cancers, cardiac arrhythmias and other medical conditions. During treatment, microwaves are applied directly to tissues to produce rapid temperature elevations sufficient to produce immediate coagulative necrosis. The engineering design criteria for each application differ, with individual consideration for factors such as desired ablation zone size, treatment duration, and procedural invasiveness. Recent technological developments in applicator cooling, power control and system optimization for specific applications promise to increase the utilization of microwave ablation in the future. This article will review the basic biophysics of microwave tissue heating, provide an overview of the design and operation of current equipment, and outline areas for future research for microwave ablation. PMID:21175404

  20. Indications and options for endometrial ablation.

    PubMed

    2008-11-01

    Endometrial ablation is an effective therapeutic option for the management of menorrhagia in properly selected patients. Hysteroscopic and non-hysteroscopic techniques offer similar rates of symptom relief and patient satisfaction.

  1. Percutaneous ablation of malignant thoracic tumors.

    PubMed

    Ghaye, B

    2013-01-01

    Lung cancer is the leading cause of death related to cancer. Fifteen to thirty percent of patients with a localized lung cancer are actually inoperable as they present with poor general condition, limited cardiopulmonary function, or a too high surgical risk. Therefore, minimally invasive treatments are needed and percutaneous ablation seems an attractive option. Thermal ablation can be performed by delivering heat (radiofrequency, microwave, laser) or cold (cryotherapy) through a needle inserted into the tumor under CT guidance. The ideal lesion is less than 2 or 3 cm in diameter. Success of percutaneous thermal ablation appears to be close to those of surgery for localized lung cancer. Nevertheless studies are still needed to definitely assess the role of ablation compared to other emerging techniques, as stereotactic radiotherapy as well as potential synergy with other treatments.

  2. Use of Ar pellet ablation rate to estimate initial runaway electron seed population in DIII-D rapid shutdown experiments

    NASA Astrophysics Data System (ADS)

    Hollmann, E. M.; Commaux, N.; Moyer, R. A.; Parks, P. B.; Austin, M. E.; Bykov, I.; Cooper, C.; Eidietis, N. W.; O'Mullane, M.; Paz-Soldan, C.; Rudakov, D. L.; Shiraki, D.

    2017-01-01

    Small (2-3 mm, 0.9-2 Pa · m3) argon pellets are used in the DIII-D tokamak to cause rapid shutdown (disruption) of discharges. The Ar pellet ablation is typically found to be much larger than expected from the thermal plasma electron temperature alone; the additional ablation is interpreted as being due to non-thermal runaway electrons (REs) formed during the pellet-induced temperature collapse. Simple estimates of the RE seed current using the enhanced ablation rate give values of order 1-10 kA, roughly consistent with estimates based on avalanche theory. Analytic estimates of the RE seed current based on the Dreicer formula tend to significantly underestimate it, while estimates based on the hot tail model significantly overestimate it.

  3. Stable glow discharge detector

    DOEpatents

    Koo, Jackson C.; Yu, Conrad M.

    2004-05-18

    A highly sensitive electronic ion cell for the measurement of trace elements in He carrier gas which involves glow discharge. A constant wave (CW) stable glow discharge detector which is controlled through a biased resistor, can detect the change of electron density caused by impurities in the He carrier gas by many orders of magnitude larger than that caused by direct ionization or electron capture. The stable glow discharge detector utilizes a floating pseudo-electrode to form a probe in or near the plasma and a solid rod electrode. By using this probe, the large variation of electron density due to trace amounts of impurities can be directly measured. The solid rod electrode provides greater stability and thus easier alignment.

  4. Flexible Ablators: Applications and Arcjet Testing

    NASA Technical Reports Server (NTRS)

    Arnold, James O.; Venkatapathy, Ethiraj; Beck, Robin A S.; Mcguire, Kathy; Prabhu, Dinesh K.; Gorbunov, Sergey

    2011-01-01

    Flexible ablators were conceived in 2009 to meet the technology pull for large, human Mars Exploration Class, 23 m diameter hypersonic inflatable aerodynamic decelerators. As described elsewhere, they have been recently undergoing initial technical readiness (TRL) advancement by NASA. The performance limits of flexible ablators in terms of maximum heat rates, pressure and shear remain to be defined. Further, it is hoped that this emerging technology will vastly expand the capability of future NASA missions involving atmospheric entry systems. This paper considers four topics of relevance to flexible ablators: (1) Their potential applications to near/far term human and robotic missions (2) Brief consideration of the balance between heat shield diameter, flexible ablator performance limits, entry vehicle controllability and aft-body shear layer impingement of interest to designers of very large entry vehicles, (3) The approach for developing bonding processes of flexible ablators for use on rigid entry bodies and (4) Design of large arcjet test articles that will enable the testing of flexible ablators in flight-like, combined environments (heat flux, pressure, shear and structural tensile loading). Based on a review of thermal protection system performance requirements for future entry vehicles, it is concluded that flexible ablators have broad applications to conventional, rigid entry body systems and are enabling to large deployable (both inflatable and mechanical) heat shields. Because of the game-changing nature of flexible ablators, it appears that NASA's Office of the Chief Technologist (OCT) will fund a focused, 3-year TRL advancement of the new materials capable of performance in heat fluxes in the range of 200-600 W/sq. cm. This support will enable the manufacture and use of the large-scale arcjet test designs that will be a key element of this OCT funded activity.

  5. Resonant laser ablation: mechanisms and applications

    SciTech Connect

    Anderson, J.E.; Allen, T.M.; Garrett, A.W.; Gill, C.G.; Hemberger, P.H.; Kelly, P.B.; Nogar, N.S.

    1996-10-01

    We report on aspects of resonant laser ablation (RLA) behavior for a number of sample types: metals, alloys, thin films, zeolites and soil. The versatility of RLA is demonstrated, with results on a variety of samples and in several mass spectrometers. In addition, the application to depth profiling of thin films is described; absolute removal rates and detection limits are also displayed. A discussion of possible mechanisms for low-power ablation is presented.

  6. Percutaneous ablation of colorectal lung metastases

    PubMed Central

    Solomon, Stephen B.

    2015-01-01

    Lung metastasectomy can prolong survival in patients with metastatic colorectal carcinoma. Thermal ablation offers a potential solution with similar reported survival outcomes. It has minimal effect on pulmonary function, or quality of life, can be repeated, and may be considered more acceptable to patients because of the associated shorter hospital stay and recovery. This review describes the indications, technique, reported outcomes, complications and radiologic appearances after thermal ablation of colorectal lung metastases. PMID:26697202

  7. Antarctic subglacial lake discharges

    NASA Astrophysics Data System (ADS)

    Pattyn, Frank

    Antarctic subglacial lakes were long time supposed to be relatively closed and stable environments with long residence times and slow circulations. This view has recently been challenged with evidence of active subglacial lake discharge underneath the Antarctic ice sheet. Satellite altimetry observations witnessed rapid changes in surface elevation across subglacial lakes over periods ranging from several months to more than a year, which were interpreted as subglacial lake discharge and subsequent lake filling, and which seem to be a common and widespread feature. Such discharges are comparable to jökulhlaups and can be modeled that way using the Nye-Röthlisberger theory. Considering the ice at the base of the ice sheet at pressure melting point, subglacial conduits are sustainable over periods of more than a year and over distances of several hundreds of kilometers. Coupling of an ice sheet model to a subglacial lake system demonstrated that small changes in surface slope are sufficient to start and sustain episodic subglacial drainage events on decadal time scales. Therefore, lake discharge may well be a common feature of the subglacial hydrological system, influencing the behavior of large ice sheets, especially when subglacial lakes are perched at or near the onset of large outlet glaciers and ice streams. While most of the observed discharge events are relatively small (101-102 m3 s-1), evidence for larger subglacial discharges is found in ice free areas bordering Antarctica, and witnessing subglacial floods of more than 106 m3 s-1 that occurred during the middle Miocene.

  8. Laser Ablated Carbon Nanodots for Light Emission.

    PubMed

    Reyes, Delfino; Camacho, Marco; Camacho, Miguel; Mayorga, Miguel; Weathers, Duncan; Salamo, Greg; Wang, Zhiming; Neogi, Arup

    2016-12-01

    The synthesis of fluorescent carbon dots-like nanostructures (CNDs) obtained through the laser ablation of a carbon solid target in liquid environment is reported. The ablation process was induced in acetone with laser pulses of 1064, 532, and 355 nm under different irradiation times. Close-spherical amorphous CNDs with sizes between 5 and 20 nm, whose abundance strongly depends on the ablation parameters were investigated using electron microscopy and was confirmed using absorption and emission spectroscopies. The π- π* electronic transition at 3.76 eV dominates the absorption for all the CNDs species synthesized under different irradiation conditions. The light emission is most efficient due to excitation at 3.54 eV with the photoluminescence intensity centered at 3.23 eV. The light emission from the CNDs is most efficient due to ablation at 355 nm. The emission wavelength of the CNDs can be tuned from the near-UV to the green wavelength region by controlling the ablation time and modifying the ablation and excitation laser wavelength.

  9. Pulsed HF laser ablation of dentin

    NASA Astrophysics Data System (ADS)

    Papagiakoumou, Eirini I.; Papadopoulos, Dimitris N.; Makropoulou, Mersini I.; Khabbaz, Maruan G.; Serafetinides, Alexander A.

    2005-03-01

    The interaction of a TEA (Transversally Excited Atmospheric pressure) corona preionized oscillator double amplifier HF (hydrogen fluoride) laser beam with dentin tissue is reported. Pulses of 39 ns in the wavelength range of 2.65-3.35 μm and output energies in the range of 10-45 mJ, in a predominantly TEM00 beam were used to interact with dentin tissue. Ablation experiments were conducted with the laser beam directly focused on the tissue. Several samples of freshly extracted human teeth were used, cut longitudinally in facets of about 1mm thick and stored in phosphate buffered saline after being cleaned from the soft tissue remains. The experimental data (ablation thresholds, ablation rates) are discussed with respect to the ablation mechanism(s). Adequate tissue removal was observed and the ablation behavior was, in the greates part of the available fluences, almost linear. From the microscopic examination of teh samples, in a scanning electron microscope (SEM), the irradiated surfaces displayed oval craters (reflecting the laser beam shape) with absence of any melting or carbonization zone. It is suggested that the specific laser removes hard tissue by a combined photothermal and plasma mediated ablation mechanism, leaving a surface free from thermal damage and with a well-shaped crater.

  10. Gold nanoparticle-coated capillaries for protein and peptide analysis on open-tubular capillary electrochromatography.

    PubMed

    Hamer, Mariana; Yone, Angel; Rezzano, Irene

    2012-01-01

    We report a new method of immobilization of gold nanoparticles (AuNPs) on a fused-silica capillary through covalent binding. The resulting modified capillary was applied to electrophoretic systems to improve the efficiency of separation and the selectivity of selected solutes. The immobilization of AuNPs on the capillary wall was performed in a very simple and fast way without requiring heating. The surface features of an AuNP-coated capillary column were determined using the scanning electron microscopy. The chromatographic properties of AuNP-coated capillaries were investigated through variation of the buffer pH and separation voltage. Effective separations of synthetic peptides mixture were obtained on the AuNP-coated capillaries. The method shows a remarkable stability since it was reused about 900 times. The capacity factor was duplicated. Therefore, this modification is stable and can be applied to different separation purposes. A complex mixture of tryptic peptide fragments of HSA was analyzed in both the bare- and the AuNP-coated capillaries. Better electrophoretic peptide profile was observed when using the AuNP-coated capillary.

  11. Capillary electrophoresis in a fused-silica capillary with surface roughness gradient.

    PubMed

    Horká, Marie; Šlais, Karel; Karásek, Pavel; Růžička, Filip; Šalplachta, Jiří; Šesták, Jozef; Kahle, Vladislav; Roth, Michal

    2016-10-01

    The electro-osmotic flow, a significant factor in capillary electrophoretic separations, is very sensitive to small changes in structure and surface roughness of the inner surface of fused silica capillary. Besides a number of negative effects, the electro-osmotic flow can also have a positive effect on the separation. An example could be fused silica capillaries with homogenous surface roughness along their entire separation length as produced by etching with supercritical water. Different strains of methicillin-resistant and methicillin-susceptible Staphylococcus aureus were separated on that type of capillaries. In the present study, fused-silica capillaries with a gradient of surface roughness were prepared and their basic behavior was studied in capillary zone electrophoresis with UV-visible detection. First the influence of the electro-osmotic flow on the peak shape of a marker of electro-osmotic flow, thiourea, has been discussed. An antifungal agent, hydrophobic amphotericin B, and a protein marker, albumin, have been used as model analytes. A significant narrowing of the detected zones of the examined analytes was achieved in supercritical-water-treated capillaries as compared to the electrophoretic separation in smooth capillaries. Minimum detectable amounts of 5 ng/mL amphotericin B and 5 μg/mL albumin were reached with this method.

  12. Two-dimensional capillary electrophoresis: capillary isoelectric focusing and capillary zone electrophoresis with laser-induced fluorescence detection.

    PubMed

    Dickerson, Jane A; Ramsay, Lauren M; Dada, Oluwatosin O; Cermak, Nathan; Dovichi, Norman J

    2010-08-01

    CIEF and CZE are coupled with LIF detection to create an ultrasensitive 2-D separation method for proteins. In this method, two capillaries are joined through a buffer-filled interface. Separate power supplies control the potential at the injection end of the first capillary and at the interface; the detector is held at ground potential. Proteins are labeled with the fluorogenic reagent Chromeo P503, which preserves the isoelectric point of the labeled protein. The labeled proteins were mixed with ampholytes and injected into the first-dimension capillary. A focusing step was performed with the injection end of the capillary at high pH and the interface at low pH. To mobilize components, the interface was filled with a high pH buffer, which was compatible with the second-dimension separation. A fraction was transferred to the second-dimension capillary for separation. The process of fraction transfer and second dimension separation was repeated two dozen times. The separation produced a spot capacity of 125.

  13. Microfluidic flow counterbalanced capillary electrophoresis.

    PubMed

    Xia, Ling; Dutta, Debashis

    2013-04-07

    Flow counterbalanced capillary electrophoresis (FCCE) offers a powerful approach to realizing difficult charge based separations in compact microchip devices with application of relatively small electrical voltages. The need for dynamically controlling the pressure-gradient in the FCCE column however presents a significant challenge in implementing this technique on the microchip platform. In this article, we report the use of a simple on-chip pumping unit that allows precise introduction of a periodic pressure-driven backflow into a microfluidic separation channel enabling an FCCE analysis. The backflow in our device was produced by fabricating a shallow segment (0.5 μm deep) downstream of the analysis column (5 μm deep) and applying an electric field across it. A mismatch in the electroosmotic transport rate at the interface of this segment was shown to yield a pressure-gradient that could reverse the flow of the analyte bands without inverting the direction of the electric field. Although such a pressure-gradient also led to additional band broadening in the system, overall, the separation resolution of our device was observed to improve with an increasing number of back-and-forth sample passes through the analysis channel. For our current design, the corresponding improvement in the effective separation length was as much as 52% of the actual distance travelled by the chosen FITC-labeled amino acid samples. The reported device is well suited for further miniaturization of the FCCE method to the nanofluidic length scale which likely would improve its performance, and is easily integrable to other analytical procedures on the microchip platform for lab-on-a-chip applications.

  14. Critical Velocities in Open Capillary Flow

    NASA Technical Reports Server (NTRS)

    Dreyer, Michael; Langbein, Dieter; Rath, Hans J.

    1996-01-01

    This paper describes the proposed research program on open capillary flow and the preliminary work performed theoretically and in drop tower experiments. The work focuses on the fundamental physical understanding of the flow through capillary bound geometries, where the circumference of the cross section of the flow path contains free surfaces. Examples for such a flow configuration are capillary vanes in surface tension tanks, flow along edges and corners and flow through liquid bridges. The geometries may be classified by their cross section areas, wetted circumferences and the radii of curvature of the free surfaces. In the streaming float zone the flow path is bound by a free surface only. The ribbon vane is a model for vane types used in surface tension tanks, where a structure in proximity to the tank wall forms a capillary gap. A groove is used in heat pipes for the transportation of the condensed working fluid to the heat source and a wedge may occur in a spaceborne experiment where fluid has to be transported by the means of surface tension. The research objectives are the determination of the maximum volume flux, the observation of the free surfaces and the liquid flow inside the flow path as well as the evaluation of the limiting capillary wave speed. The restriction of the maximum volume flux is due to convective forces (flow velocity exceeding the capillary wave speed) and/or viscous forces, i.e. the viscous head loss along the flow path must be compensated by the capillary pressure due to the curved free surface. Exceeding the maximum volume flux leads to the choking of the flow path, thus the free surface collapses and.gas ingestion occurs at the outlet. The means are ground-based experimental work with plateau tanks and in a drop tower, a sounding rocket flight, and theoretical analysis with integral balances as well as full three dimensional CFD solutions for flow with free surfaces.

  15. Capillary adhesion at the nanometer scale.

    PubMed

    Cheng, Shengfeng; Robbins, Mark O

    2014-06-01

    Molecular dynamics simulations are used to study the capillary adhesion from a nonvolatile liquid meniscus between a spherical tip and a flat substrate. The atomic structure of the tip, the tip radius, the contact angles of the liquid on the two surfaces, and the volume of the liquid bridge are varied. The capillary force between the tip and substrate is calculated as a function of their separation h. The force agrees with continuum predictions based on macroscopic theory for h down to ∼5 to 10 nm. At smaller h, the force tends to be less attractive than predicted and has strong oscillations. This oscillatory component of the capillary force is completely missed in the macroscopic theory, which only includes contributions from the surface tension around the circumference of the meniscus and the pressure difference over the cross section of the meniscus. The oscillation is found to be due to molecular layering of the liquid confined in the narrow gap between the tip and substrate. This effect is most pronounced for large tip radii and/or smooth surfaces. The other two components considered by the macroscopic theory are also identified. The surface tension term, as well as the meniscus shape, is accurately described by the macroscopic theory for h down to ∼1 nm, but the capillary pressure term is always more positive than the corresponding continuum result. This shift in the capillary pressure reduces the average adhesion by a factor as large as 2 from its continuum value and is found to be due to an anisotropy in the pressure tensor. The component in the plane of the substrate is consistent with the capillary pressure predicted by the macroscopic theory (i.e., the Young-Laplace equation), but the normal pressure that determines the capillary force is always more positive than the continuum counterpart.

  16. Joule heating and determination of temperature in capillary electrophoresis and capillary electrochromatography columns.

    PubMed

    Rathore, Anurag S

    2004-05-28

    This article reviews the progress that has taken place in the past decade on the topic of estimation of Joule heating and temperature inside an open or packed capillary in electro-driven separation techniques of capillary electrophoresis (CE) and capillary electrochromatography (CEC), respectively. Developments in theoretical modeling of the heat transfer in the capillary systems have focused on attempts to apply the existing models on newer techniques such as CEC and chip-based CE. However, the advent of novel analytical tools such as pulsed magnetic field gradient nuclear magnetic resonance (NMR), NMR thermometry, and Raman spectroscopy, have led to a revolution in the area of experimental estimation of Joule heating and temperature inside the capillary via the various noninvasive techniques. This review attempts to capture the major findings that have been reported in the past decade.

  17. Separation of Recombinant Therapeutic Proteins Using Capillary Gel Electrophoresis and Capillary Isoelectric Focusing.

    PubMed

    De Jong, Caitlyn A G; Risley, Jessica; Lee, Alexis K; Zhao, Shuai Sherry; Chen, David D Y

    2016-01-01

    Detailed step-by-step methods for protein separation techniques based on capillary electrophoresis (CE) are described in this chapter. Focus is placed on two techniques, capillary gel electrophoresis (CGE) and capillary isoelectric focusing (cIEF). CGE is essentially gel electrophoresis, performed in a capillary, where a hydrogel is used as a sieving matrix to separate proteins or peptides based on size. cIEF separates proteins or peptides based on their isoelectric point (pI), the pH at which the protein or peptide bears no charges. Detailed protocols and steps (including capillary preparation, sample preparation, CE separation conditions, and detection) for both CGE and cIEF presented so that readers can follow the described methods in their own labs.

  18. High speed and reproducible analysis of nitrosamines by capillary electrophoresis with a sulfonated capillary.

    PubMed

    Taga, Atsushi; Nishi, Tomoko; Honda, Yoshitaka; Sato, Atsushi; Terashima, Hiroyuki; Suzuki, Kentaro; Kodama, Shuji; Boki, Keito

    2007-01-01

    Recently environmental control is regarded as important for good human health conditions, and toxic substances, including carcinogens and endocrine disruptors should be eliminated from our living environment. Hence easy quantitative methods are expected for a high level of environmental control. Our previous paper describes an easy quantitative analysis of nitrosamines (NAs) by capillary electrophoresis with an untreated fused silica capillary installed in an ordinary apparatus. In this paper, utilizing a novel type capillary column having sulfonated inner wall was investigated for improvements of separation performance and reproducibility. A sulfonated capillary causes fast and stabile electroosmotic flow because its inner wall is strongly negative charged. On a performance comparison of a sulfonated capillary with an untreated fused silica, analysis time reduction of c.a. forty percent was achieved, and relative standard deviations of migration times and peak responses were less than one third. In addition sample concentrations giving detection and quantitation limits were also reduced to a half.

  19. Longitudinal discharge laser baffles

    DOEpatents

    Warner, B.E.; Ault, E.R.

    1994-06-07

    The IR baffles placed between the window and the electrode of a longitudinal discharge laser improve laser performance by intercepting off-axis IR radiation from the laser and in doing so reduce window heating and subsequent optical distortion of the laser beam. 1 fig.

  20. Longitudinal discharge laser baffles

    DOEpatents

    Warner, Bruce E.; Ault, Earl R.

    1994-01-01

    The IR baffles placed between the window and the electrode of a longitudinal discharge laser improve laser performance by intercepting off-axis IR radiation from the laser and in doing so reduce window heating and subsequent optical distortion of the laser beam.

  1. The Mid-Term Results of Patients who Underwent Radiofrequency Atrial Fibrillation Ablation Together with Mitral Valve Surgery

    PubMed Central

    Çolak, Abdurrahim; Kaya, Ugur; Ceviz, Munacettin; Becit, Necip; Kocak, Hikmet

    2016-01-01

    Objetive Saline-irrigated radiofrequency ablation, which has been widely used for surgical treatment of atrial fibrillation in recent years, is 80-90% successful in achieving sinus rhythm. In our study, our surgical experience and mid-term results in patients who underwent mitral valve surgery and left atrial radiofrequency ablation were analyzed. Methods Forty patients (15 males, 25 females; mean age 52.05±9.9 years; range 32-74) underwent surgery for atrial fibrillation associated with mitral valvular disease. All patients manifested atrial fibrillation, which started at least six months before the surgical intervention. The majority of patients (36 patients, 90%) were in NYHA class III; 34 (85%) patients had rheumatic heart disease. In addition to mitral valve surgery and radiofrequency ablation, coronary artery bypass, DeVega tricuspid annuloplasty, left ventricular aneurysm repair, and left atrial thrombus excision were performed. Following discharge from the hospital, patients' follow-up was performed as outpatient clinic examinations and the average follow-up period of patients was 18±3 months. Results While the incidence of sinus rhythm was 85.3% on the first postoperative day, it was 80% during discharge and 71% in the 1st year follow-up examination. Conclusion Radiofrequency ablation is an effective method when it is performed by appropriate surgical technique. Its rate for returning to sinus rhythm is as high as the rate of conventional surgical procedure. PMID:27849303

  2. Dust ablation in Pluto's atmosphere

    NASA Astrophysics Data System (ADS)

    Horanyi, Mihaly; Poppe, Andrew; Sternovsky, Zoltan

    2016-04-01

    Based on measurements by dust detectors onboard the Pioneer 10/11 and New Horizons spacecraft the total production rate of dust particles born in the Edgeworth Kuiper Belt (EKB) has been be estimated to be on the order of 5 ṡ 103 kg/s in the approximate size range of 1 - 10 μm. Dust particles are produced by collisions between EKB objects and their bombardment by both interplanetary and interstellar dust particles. Dust particles of EKB origin, in general, migrate towards the Sun due to Poynting-Robertson drag but their distributions are further sculpted by mean-motion resonances as they first approach the orbit of Neptune and later the other planets, as well as mutual collisions. Subsequently, Jupiter will eject the vast majority of them before they reach the inner solar system. The expected mass influx into Pluto atmosphere is on the order of 200 kg/day, and the arrival speed of the incoming particles is on the order of 3 - 4 km/s. We have followed the ablation history as function of speed and size of dust particles in Pluto's atmosphere, and found that volatile rich particles can fully sublimate due to drag heating and deposit their mass in narrow layers. This deposition might promote the formation of the haze layers observed by the New Horizons spacecraft. This talk will explore the constraints on the composition of the dust particles by comparing the altitude of the deposition layers to the observed haze layers.

  3. Radiofrequency Ablation Beyond the Liver

    PubMed Central

    Neeman, Ziv; Wood, Bradford J.

    2008-01-01

    Radiofrequency ablation (RFA) has begun to show promise for extrahepatic indications. Although much of the reported work on image-guided RFA of liver neoplasms is quite promising, it is even earlier in the evaluation and validation process for extrahepatic RFA, with few short-term and no long-term studies reported. Although there are much more data for liver RFA with almost 3,000 cases reported in the literature, there are a number of ongoing investigations of RFA for tumors in the kidney, lung, bone, breast, bone, and adrenal gland. Debulking and pain control with RFA present palliative options becoming increasingly popular weapons in the interventionalist's oncology arsenal. Metastatic disease with a wide variety of primary histologies in a myriad of locations may be treated with RFA after a careful consideration of the risk-to-benefit ratio balance. The RFA technique can be slightly different outside the liver. Specifically, differing dielectric tissue characteristics may markedly alter the RFA treatment. Each different RFA system has a unique risk and advantage profile. Extrahepatic indications and contraindications will be suggested. Treatment tips and the unique complications and considerations will be introduced for some of the more common extrahepatic locations. PMID:12524646

  4. Plans and status of the Beryllium ablator campaign on NIF

    NASA Astrophysics Data System (ADS)

    Kline, J. L.; Yi, S. A.; Simakov, A. N.; Wilson, D. C.; Olson, R. E.; Krasheninnikova, N. S.; Kyrala, G. A.; Perry, T. S.; Batha, S. H.; Dewald, E. L.; Edwards, M. J.; MacKinnon, A. J.; Meezan, N. B.

    2014-10-01

    Beryllium has long been known to have excellent properties for indirectly driven ICF implosions including enhanced ablation pressure, implosion velocity, and mass ablation rate. The high ablation velocity leads to stabilization of ablative hydrodynamic instabilities and higher ablation pressures. Recent ``high foot'' experiments have shown ablative Rayleigh-Taylor to be a leading cause of degraded performance for ICF implosions. While Beryllium ablators have these advantages, there are also risks associated with Beryllium target designs. A campaign is underway to design and to test these advantages for comparison with other ablator options and determine which provides the best path forward for ICF. Experiments using Beryllium ablators are expected to start in the late summer of 2014. This presentation will discuss the status of the experiments and layout the plans/goals for the campaign. This work is supported by the US DOE.

  5. Percutaneous Microwave Ablation of Renal Angiomyolipomas

    SciTech Connect

    Cristescu, Mircea; Abel, E. Jason; Wells, Shane Ziemlewicz, Timothy J.; Hedican, Sean P.; Lubner, Megan G. Hinshaw, J. Louis Brace, Christopher L. Lee, Fred T.

    2016-03-15

    PurposeTo evaluate the safety and efficacy of US-guided percutaneous microwave (MW) ablation in the treatment of renal angiomyolipoma (AML).Materials and MethodsFrom January 2011 to April 2014, seven patients (5 females and 2 males; mean age 51.4) with 11 renal AMLs (9 sporadic type and 2 tuberous sclerosis associated) with a mean size of 3.4 ± 0.7 cm (range 2.4–4.9 cm) were treated with high-powered, gas-cooled percutaneous MW ablation under US guidance. Tumoral diameter, volume, and CT/MR enhancement were measured on pre-treatment, immediate post-ablation, and delayed post-ablation imaging. Clinical symptoms and creatinine were assessed on follow-up visits.ResultsAll ablations were technically successful and no major complications were encountered. Mean ablation parameters were ablation power of 65 W (range 60–70 W), using 456 mL of hydrodissection fluid per patient, over 4.7 min (range 3–8 min). Immediate post-ablation imaging demonstrated mean tumor diameter and volume decreases of 1.8 % (3.4–3.3 cm) and 1.7 % (27.5–26.3 cm{sup 3}), respectively. Delayed imaging follow-up obtained at a mean interval of 23.1 months (median 17.6; range 9–47) demonstrated mean tumor diameter and volume decreases of 29 % (3.4–2.4 cm) and 47 % (27.5–12.1 cm{sup 3}), respectively. Tumoral enhancement decreased on immediate post-procedure and delayed imaging by CT/MR parameters, indicating decreased tumor vascularity. No patients required additional intervention and no patients experienced spontaneous bleeding post-ablation.ConclusionOur early experience with high-powered, gas-cooled percutaneous MW ablation demonstrates it to be a safe and effective modality to devascularize and decrease the size of renal AMLs.

  6. A systematic review of surgical ablation versus catheter ablation for atrial fibrillation

    PubMed Central

    Kearney, Katherine; Stephenson, Rowan; Phan, Kevin; Chan, Wei Yen; Huang, Min Yin

    2014-01-01

    Background Atrial fibrillation (AF) is an increasingly prevalent condition in the ageing population, with significantly associated morbidity and mortality. Surgical and catheter ablative strategies both aim to reduce mortality and morbidity through freedom from AF. This review consolidates all currently available comparative data to evaluate these two interventions. Methods A systematic search was conducted across MEDLINE, PubMed, Embase, Cochrane Central Register of Controlled Trials and the Cochrane Database of Systematic Reviews from January 2000 until August 2013. All studies were critically appraised and only those directly comparing surgical and catheter ablation were included. Results Seven studies were deemed suitable for analysis according to the inclusion criteria. Freedom from AF was significantly higher in the surgical ablation group versus the catheter ablation group at 6-month, 12-month and study endpoint follow-up periods. Subgroup analysis demonstrated similar trends, with higher freedom from AF in the surgical ablation group for paroxysmal AF patients. The incidence of pacemaker implantation was higher, while no difference in stroke or cardiac tamponade was demonstrated for the surgical versus catheter ablation groups. Conclusions Current evidence suggests that epicardial ablative strategies are associated with higher freedom from AF, higher pacemaker implantation rates and comparable neurological complications and cardiac tamponade incidence to catheter ablative treatment. Other complications and risks were poorly reported, which warrants further randomized controlled trials (RCTs) of adequate power and follow-up duration. PMID:24516794

  7. Bone marrow transplant – children - discharge

    MedlinePlus

    Transplant - bone marrow - children - discharge; Stem cell transplant - children - discharge; Hematopoietic stem cell transplant -children - discharge; Reduced intensity, non-myeloablative transplant - children - discharge; Mini transplant - children - discharge; Allogenic ...

  8. Capillary liquid chromatography using laser-based and mass spectrometric detection. [Capillary zone electrophoresis (CZE); micellar electrokinetic capillary kchromatography (MECC)

    SciTech Connect

    Sepaniak, M.J.; Cook, K.D.

    1992-01-01

    In the years following the 1986 seminal paper (J. Chromatogr. Sci., 24, 347-352) describing modern capillary zone electrophoresis (CZE), the prominence of capillary electrokinetic separation techniques has grown. A related electrochromatographic technique is micellar electrokinetic capillary chromatography (MECC). This report presents a brief synopsis of research efforts during the current 3-year period. In addition to a description of analytical separations-based research, results of efforts to develop and expand spectrometric detection for the techniques is reviewed. Laser fluorometric detection schemes have been successfully advanced. Mass spectrometric research was less fruitful, largely owing to personnel limitations. A regenerable fiber optic sensor was developed that can be used to remotely monitor chemical carcinogens, etc. (DLC)

  9. Online monitoring of nanoparticles formed during nanosecond laser ablation

    NASA Astrophysics Data System (ADS)

    Nováková, Hana; Holá, Markéta; Vojtíšek-Lom, Michal; Ondráček, Jakub; Kanický, Viktor

    2016-11-01

    The particle size distribution of dry aerosol originating from laser ablation of glass material was monitored simultaneously with Laser Ablation - Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) analysis and two aerosol spectrometers - Fast Mobility Particle Sizer (FMPS) and Aerodynamic Particle Sizer (APS). The unique combination of LA-ICP-MS and FMPS offers the possibility of measuring the particle size distribution every 1 s of the ablation process in the size range of 5.6-560 nm. APS extends the information about particle concentration in the size range 0.54-17 μm. Online monitoring of the dry aerosol was performed for two ablation modes (spot and line with a duration of 80 s) with a 193 nm excimer laser system, using the glass reference material NIST 610 as a sample. Different sizes of laser spot for spot ablation and different scan speeds for line ablation were tested. It was found that the FMPS device is capable of detecting changes in particle size distribution at the first pulses of spot laser ablation and is suitable for laser ablation control simultaneously with LA-ICP-MS analysis. The studied parameters of laser ablation have an influence on the resulting particle size distribution. The line mode of laser ablation produces larger particles during the whole ablation process, while spot ablation produces larger particles only at the beginning, during the ablation of the intact layer of the ablated material. Moreover, spot ablation produces more primary nano-particles (in ultrafine mode size range < 100 nm) than line ablation. This effect is most probably caused by a reduced amount of large particles released from the spot ablation crater. The larger particles scavenge the ultrafine particles during the line ablation mode.

  10. Thermal lens detector system for capillary electrophoresis

    NASA Astrophysics Data System (ADS)

    Seidel, Bernd S.; Faubel, Werner N.; Ache, Hans-Joachim

    1997-07-01

    The characteristics and the performance of a thermal lens detector, which uses a double-beam absorption scheme, were studied in a capillary electrophoresis system with various types of toxic pollutants, e.g., pesticides. The setup of the detector system was miniaturized using the smallest diverging path lengths between the cell and the pinhole (4 mm). The probe laser beam (He:Ne laser, 633 nm) and the excitation beam (Ar+ ion laser, 364, 457, 488, and 514 nm) with a crossed setup were directed by mirrors into two microscope objectives that focused the beam to a 5-micrometers waist inside the capillary. The detection volume was on the order of 75 nl when a 75-micrometers capillary was employed. The change in intensity of the probe beam was detected by a photodiode behind a pinhole, which was protected with different band-pass interference filters. The excitation laser can be used in the multiline order. Micellar electrokinetic methods are used for pesticide separation. The performance of the detector in capillary electrophoresis was assessed with various types of capillaries and compared with a conventional absorption detector. The limit of detection is at least one order of magnitude better than it is with the absorption detector.

  11. Synthetic Capillaries to Control Microscopic Blood Flow

    NASA Astrophysics Data System (ADS)

    Sarveswaran, K.; Kurz, V.; Dong, Z.; Tanaka, T.; Penny, S.; Timp, G.

    2016-02-01

    Capillaries pervade human physiology. The mean intercapillary distance is only about 100 μm in human tissue, which indicates the extent of nutrient diffusion. In engineered tissue the lack of capillaries, along with the associated perfusion, is problematic because it leads to hypoxic stress and necrosis. However, a capillary is not easy to engineer due to its complex cytoarchitecture. Here, it is shown that it is possible to create in vitro, in about 30 min, a tubular microenvironment with an elastic modulus and porosity consistent with human tissue that functionally mimicks a bona fide capillary using “live cell lithography”(LCL) to control the type and position of cells on a composite hydrogel scaffold. Furthermore, it is established that these constructs support the forces associated with blood flow, and produce nutrient gradients similar to those measured in vivo. With LCL, capillaries can be constructed with single cell precision—no other method for tissue engineering offers such precision. Since the time required for assembly scales with the number of cells, this method is likely to be adapted first to create minimal functional units of human tissue that constitute organs, consisting of a heterogeneous population of 100–1000 cells, organized hierarchically to express a predictable function.

  12. Restructuring and aging in a capillary suspension

    PubMed Central

    Koos, Erin; Kannowade, Wolfgang; Willenbacher, Norbert

    2014-01-01

    The rheological properties of capillary suspensions, suspensions with small amounts of an added immiscible fluid, are dramatically altered with the addition of the secondary fluid. We investigate a capillary suspension to determine how the network ages and restructures at rest and under applied external shear deformation. The present work uses calcium carbonate suspended in silicone oil (11 % solids) with added water as a model system. Aging of capillary suspensions and their response to applied oscillatory shear is distinctly different from particulate gels dominated by the van der Waals forces. The suspensions dominated by the capillary force are very sensitive to oscillatory flow, with the linear viscoelastic regime ending at a deformation of only 0.1% and demonstrating power-law aging behavior. This aging persists for long times at low deformations or for shorter times with a sudden decrease in the strength at higher deformations. This aging behavior suggests that the network is able to rearrange and even rupture. This same sensitivity is not demonstrated in shear flow where very high shear rates are required to rupture the agglomerates returning the apparent viscosity of capillary suspensions to the same viscosity as for the pure vdW suspension. A transitional region is also present at intermediate water contents wherein the material response depends very strongly on the type, strength, and duration of the external forcing. PMID:25729113

  13. Synthetic Capillaries to Control Microscopic Blood Flow

    PubMed Central

    Sarveswaran, K.; Kurz, V.; Dong, Z.; Tanaka, T.; Penny, S.; Timp, G.

    2016-01-01

    Capillaries pervade human physiology. The mean intercapillary distance is only about 100 μm in human tissue, which indicates the extent of nutrient diffusion. In engineered tissue the lack of capillaries, along with the associated perfusion, is problematic because it leads to hypoxic stress and necrosis. However, a capillary is not easy to engineer due to its complex cytoarchitecture. Here, it is shown that it is possible to create in vitro, in about 30 min, a tubular microenvironment with an elastic modulus and porosity consistent with human tissue that functionally mimicks a bona fide capillary using “live cell lithography”(LCL) to control the type and position of cells on a composite hydrogel scaffold. Furthermore, it is established that these constructs support the forces associated with blood flow, and produce nutrient gradients similar to those measured in vivo. With LCL, capillaries can be constructed with single cell precision—no other method for tissue engineering offers such precision. Since the time required for assembly scales with the number of cells, this method is likely to be adapted first to create minimal functional units of human tissue that constitute organs, consisting of a heterogeneous population of 100–1000 cells, organized hierarchically to express a predictable function. PMID:26905751

  14. Micro-injector for capillary electrophoresis.

    PubMed

    Sáiz, Jorge; Koenka, Israel Joel; García-Ruiz, Carmen; Müller, Beat; Chwalek, Thomas; Hauser, Peter C

    2015-08-01

    A novel micro-injector for capillary electrophoresis for the handling of samples with volumes down to as little as 300 nL was designed and built in our laboratory for analyses in which the available volume is a limitation. The sample is placed into a small cavity located directly in front of the separation capillary, and the injection is then carried out automatically by controlled pressurization of the chamber with compressed air. The system also allows automated flushing of the injection chamber as well as of the capillary. In a trial with a capillary electrophoresis system with contactless conductivity detector, employing a capillary of 25 μm diameter, the results showed good stability of migration times and peak areas. To illustrate the technique, the fast separation of five inorganic cations (Na(+) , K(+) , NH4 (+) , Ca(2+) , and Mg(2+) ) was set up. This could be achieved in less than 3 min, with good limits of detection (10 μM) and linear ranges (between about 10 and 1000 μM). The system was demonstrated for the determination of the inorganic cations in porewater samples of a lake sediment core.

  15. Restructuring and aging in a capillary suspension.

    PubMed

    Koos, Erin; Kannowade, Wolfgang; Willenbacher, Norbert

    2014-12-01

    The rheological properties of capillary suspensions, suspensions with small amounts of an added immiscible fluid, are dramatically altered with the addition of the secondary fluid. We investigate a capillary suspension to determine how the network ages and restructures at rest and under applied external shear deformation. The present work uses calcium carbonate suspended in silicone oil (11 % solids) with added water as a model system. Aging of capillary suspensions and their response to applied oscillatory shear is distinctly different from particulate gels dominated by the van der Waals forces. The suspensions dominated by the capillary force are very sensitive to oscillatory flow, with the linear viscoelastic regime ending at a deformation of only 0.1% and demonstrating power-law aging behavior. This aging persists for long times at low deformations or for shorter times with a sudden decrease in the strength at higher deformations. This aging behavior suggests that the network is able to rearrange and even rupture. This same sensitivity is not demonstrated in shear flow where very high shear rates are required to rupture the agglomerates returning the apparent viscosity of capillary suspensions to the same viscosity as for the pure vdW suspension. A transitional region is also present at intermediate water contents wherein the material response depends very strongly on the type, strength, and duration of the external forcing.

  16. Contact pulsed Nd:YAG ablation of human dentin: ablation rates and tissue effects

    NASA Astrophysics Data System (ADS)

    Harris, David M.; Yessik, Michael J.

    1994-09-01

    Dentin from freshly extracted human teeth was exposed to flashlamp pumped Nd:YAG pulses (100 microsecond(s) duration, 50 - 200 mJ/pulse) delivered through a flat cut fiberoptic in contact with the dentin surface. Ablation depth and volume were measured optically and confirmed with electron microscope morphometrics. Ablation depth increased with force applied at the fiber tip up to 5 - 10 g. Above this ablation depths were insensitive to applied force. Craters made in dental stone were deeper and narrower than those made in normal dentin. Ablation depths per pulse and volumes per pulse decrease as the number of pulses increase. This is more prominent for 200 mJ pulses. At 60 mJ the ablation depths are the same from 10 to 100 Hz repetition rates, although qualitative changes (collateral damage) are greater at higher repetition rates. A progressive increase in collateral damage is seen from the 1st through the 200th pulse.

  17. Enantiomer separation of chiral pharmaceuticals by capillary electrochromatography.

    PubMed

    Wistuba, D; Schurig, V

    2000-04-14

    Enantiomer separation of chiral pharmaceuticals by capillary electrochromatography (CEC) is achieved with open-tubular capillaries (o-CEC), with packed capillaries (p-CEC) or with monolithic capillaries. In o-CEC, capillaries are coated with a thin film containing cyclodextrin derivatives, cellulose, proteins, poly-terguride or molecularly imprinted polymers as chiral selectors. In p-CEC, typical chiral HPLC stationary phases such as silica-bonded cyclodextrin or cellulose derivatives, proteins, glycoproteins, macrocyclic antibiotics, quinine-derived and 'Pirkle' selectors, polyacrylamides and molecularly imprinted polymers are used as chiral selectors. Chiral monolithic stationary phases prepared by in situ polymerization into the capillary were also developed for electrochromatographic enantiomer separation.

  18. Radioiodine Remnant Ablation: A Critical Review

    PubMed Central

    Bal, Chandra Sekhar; Padhy, Ajit Kumar

    2015-01-01

    Radioiodine remnant ablation (RRA) is considered a safe and effective method for eliminating residual thyroid tissue, as well as microscopic disease if at all present in thyroid bed following thyroidectomy. The rationale of RRA is that in the absence of thyroid tissue, serum thyroglobulin (Tg) measurement can be used as an excellent tumor marker. Other considerations are like the presence of significant remnant thyroid tissue makes detection and treatment of nodal or distant metastases difficult. Rarely, microscopic disease in the thyroid bed if not ablated, in the future, could be a source of anaplastic transformation. On the other hand, microscopic tumor emboli in distant sites could be the cause of distant metastasis too. The ablation of remnant tissue would in all probability eliminate these theoretical risks. It may be noted that all these are unproven contentious issues except postablation serum Tg estimation that could be a good tumor marker for detecting early biochemical recurrence in long-term follow-up strategy. Radioactive iodine is administered as a form of “adjuvant therapy” for remnant ablation. There have been several reports with regard to the administered dose for remnant ablation. The first report of a prospective randomized clinical trial was published from India by a prospective randomized study conducted at the All India Institute of Medical Sciences, New Delhi in the year 1996. The study reported that increasing the empirical 131I initial dose to more than 50 mCi results in plateauing of the dose-response curve and thus, conventional high-dose remnant ablation needs critical evaluation. Recently, two important studies were published: One from French group and the other from UK on a similar line. Interestingly, all three studies conducted in three different geographical regions of the world showed exactly similar conclusion. The new era of low-dose remnant ablation has taken a firm scientific footing across the continents. PMID:26420983

  19. Photoacoustic characterization of radiofrequency ablation lesions

    NASA Astrophysics Data System (ADS)

    Bouchard, Richard; Dana, Nicholas; Di Biase, Luigi; Natale, Andrea; Emelianov, Stanislav

    2012-02-01

    Radiofrequency ablation (RFA) procedures are used to destroy abnormal electrical pathways in the heart that can cause cardiac arrhythmias. Current methods relying on fluoroscopy, echocardiography and electrical conduction mapping are unable to accurately assess ablation lesion size. In an effort to better visualize RFA lesions, photoacoustic (PA) and ultrasonic (US) imaging were utilized to obtain co-registered images of ablated porcine cardiac tissue. The left ventricular free wall of fresh (i.e., never frozen) porcine hearts was harvested within 24 hours of the animals' sacrifice. A THERMOCOOLR Ablation System (Biosense Webster, Inc.) operating at 40 W for 30-60 s was used to induce lesions through the endocardial and epicardial walls of the cardiac samples. Following lesion creation, the ablated tissue samples were placed in 25 °C saline to allow for multi-wavelength PA imaging. Samples were imaged with a VevoR 2100 ultrasound system (VisualSonics, Inc.) using a modified 20-MHz array that could provide laser irradiation to the sample from a pulsed tunable laser (Newport Corp.) to allow for co-registered photoacoustic-ultrasound (PAUS) imaging. PA imaging was conducted from 750-1064 nm, with a surface fluence of approximately 15 mJ/cm2 maintained during imaging. In this preliminary study with PA imaging, the ablated region could be well visualized on the surface of the sample, with contrasts of 6-10 dB achieved at 750 nm. Although imaging penetration depth is a concern, PA imaging shows promise in being able to reliably visualize RF ablation lesions.

  20. Catheter Ablation of Fascicular Ventricular Tachycardia

    PubMed Central

    Liu, Yaowu; Fang, Zhen; Yang, Bing; Kojodjojo, Pipin; Chen, Hongwu; Ju, Weizhu; Cao, Kejiang; Chen, Minglong

    2015-01-01

    Background— Fascicular ventricular tachycardia (FVT) is a common form of sustained idiopathic left ventricular tachycardia with an Asian preponderance. This study aimed to prospectively investigate long-term clinical outcomes of patients undergoing ablation of FVT and identify predictors of arrhythmia recurrence. Methods and Results— Consecutive patients undergoing FVT ablation at a single tertiary center were enrolled. Activation mapping was performed to identify the earliest presystolic Purkinje potential during FVT that was targeted by radiofrequency ablation. Follow-up with clinic visits, ECG, and Holter monitoring was performed at least every 6 months. A total of 120 consecutive patients (mean age, 29.3±12.7 years; 82% men; all patients with normal ejection fraction) were enrolled. FVT involved left posterior fascicle and left anterior fascicle in 118 and 2 subjects, respectively. VT was noninducible in 3 patients, and ablation was acutely successful in 117 patients. With a median follow-up of 55.7 months, VT of a similar ECG morphology recurred in 17 patients, and repeat procedure confirmed FVT recurrence involving the same fascicle. Shorter VT cycle length was the only significant predictor of FVT recurrence (P=0.03). Six other patients developed new-onset upper septal FVT that was successfully ablated. Conclusions— Ablation of FVT guided by activation mapping is associated with a single procedural success rate without the use of antiarrhythmic drugs of 80.3%. Arrhythmia recurrences after an initially successful ablation were caused by recurrent FVT involving the same fascicle in two thirds of patients or new onset of upper septal FVT in the remainder. PMID:26386017

  1. Subsurface ablation of atherosclerotic plaque using ultrafast laser pulses

    PubMed Central

    Lanvin, Thomas; Conkey, Donald B.; Frobert, Aurelien; Valentin, Jeremy; Goy, Jean-Jacques; Cook, Stéphane; Giraud, Marie-Noelle; Psaltis, Demetri

    2015-01-01

    We perform subsurface ablation of atherosclerotic plaque using ultrafast pulses. Excised mouse aortas containing atherosclerotic plaque were ablated with ultrafast near-infrared (NIR) laser pulses. Optical coherence tomography (OCT) was used to observe the ablation result, while the physical damage was inspected in histological sections. We characterize the effects of incident pulse energy on surface damage, ablation hole size, and filament propagation. We find that it is possible to ablate plaque just below the surface without causing surface damage, which motivates further investigation of ultrafast ablation for subsurface atherosclerotic plaque removal. PMID:26203381

  2. Subsurface ablation of atherosclerotic plaque using ultrafast laser pulses.

    PubMed

    Lanvin, Thomas; Conkey, Donald B; Frobert, Aurelien; Valentin, Jeremy; Goy, Jean-Jacques; Cook, Stéphane; Giraud, Marie-Noelle; Psaltis, Demetri

    2015-07-01

    We perform subsurface ablation of atherosclerotic plaque using ultrafast pulses. Excised mouse aortas containing atherosclerotic plaque were ablated with ultrafast near-infrared (NIR) laser pulses. Optical coherence tomography (OCT) was used to observe the ablation result, while the physical damage was inspected in histological sections. We characterize the effects of incident pulse energy on surface damage, ablation hole size, and filament propagation. We find that it is possible to ablate plaque just below the surface without causing surface damage, which motivates further investigation of ultrafast ablation for subsurface atherosclerotic plaque removal.

  3. New tumor ablation techniques for cancer treatment (microwave, electroporation).

    PubMed

    de Baere, T; Deschamps, F

    2014-01-01

    Since the introduction of radiofrequency ablation (RFA) for the treatment of liver tumors at the end of the 1990s, indications for local ablation techniques have been extended to other organs, in particular, the lungs, kidneys and bones. These techniques have also been improved, in particular to try and overcome the limitations of radiofrequency techniques, especially the significant decrease in complete ablation rates for tumors larger than 3cm and tumors that are contiguous to vessels larger than 3mm. Microwave ablation is a rapidly developing thermal ablation technique similar to RFA but with numerous differences. Electroporation, a non-thermal ablation technique with other possibilities, is in earlier stages of clinical development.

  4. Short-Term Results of Laparoscopic Radiofrequency Ablation Using a Multipolar System for Localized Hepatocellular Carcinoma

    PubMed Central

    Morimoto, Naoki; Isoda, Norio; Takaoka, Yoshinari; Hirosawa, Takuya; Watanabe, Shunji; Otake, Toshiya; Murayama, Kozue; Fujieda, Takeshi; Tsukui, Mamiko; Miyata, Natsumi; Ono, Kohei; Yamaguchi, Shota; Yamamoto, Hironori

    2017-01-01

    Background and Aim Multipolar radiofrequency ablation (RFA) is feasible for the treatment of hepatocellular carcinoma (HCC) for which a large ablative area is planned, and it imposes a light physical burden on patients. Multipolar RFA via the percutaneous approach is performed in the majority of cases, but the efficacy of multipolar RFA with a laparoscopic approach has rarely been studied. This study aimed to evaluate the efficacy and safety of multipolar laparoscopic RFA (LRA) for localized HCC over the short term. Methods From January 2014 to January 2016, 77 consecutive patients with 130 HCCs treated by multipolar LRA were assessed. One to three bipolar needle applicators were inserted under laparoscopic ultrasonography guidance, regardless of tumor location. We intended to achieve parallel insertions and no-touch ablation as much as possible. Results The median size of the main tumor was 22 mm (range, 10-42 mm). The median follow-up time was 13.6 months (range, 3.1-24.8 months). In all cases, a sufficient ablative area was obtained as planned, without thermal injury of adjacent organs. During the follow-up period, all patients were alive with no local tumor progression, while intrahepatic recurrence distant from the primary site occurred in 7 patients. The 2-year local tumor progression-free survival rate and overall cancer-free survival rate were 100 and 81.6%, respectively. There were no procedural major complications caused prolonging the hospitalization, and all patients were discharged without subjective symptoms 4-7 days after LRA. Conclusions Multipolar LRA was efficacious in the treatment of localized HCCs by safely achieving a good ablative area. PMID:28275580

  5. Vessel Sewage Discharges: No-Discharge Zones (NDZs)

    EPA Pesticide Factsheets

    States may petition the EPA to establish areas, called no discharge zones (NDZs), where vessel sewage discharges are prohibited. This page describes how NDZs are designated, the types of designations, who enforces them, and how to comply.

  6. Capillary movement of liquid in granular beds

    SciTech Connect

    Yendler, B.; Webbon, B.

    1993-12-31

    Knowledge of capillary migration of liquids in granular beds in microgravity is essential for the development of a substrate based nutrient delivery sytem for the growth of plants in space. This problem is also interesting from the theoretical as well as the practical point of view. The purpose of this study was to model capillary water propagation through a granular bed in microgravity. In our ground experiments, water propagation is driven primarily by capillary force. Data for spherical partical sizes in the range from 0.46 to 2 mm have been obtained. It was shown that the velocity of water propagation is very sensitive to particle size. Theoretical consideration is also provided. Actual space flight experiments are planned for the future to confirm our results.

  7. Asymmetric capillary bridges between contacting spheres.

    PubMed

    Farmer, Timothy P; Bird, James C

    2015-09-15

    When a drop of liquid wets two identical solid spheres, the liquid forms a capillary bridge between the spheres to minimize surface energy. In the absence of external forces, these bridges are typically assumed to be axisymmetric, and the shape that minimizes surface energy can be calculated analytically. However under certain conditions, the bridge is axisymmetrically unstable, and migrates to a non-axisymmetric configuration. The goal of this paper is to characterize these non-axisymmetric capillary bridges. Specifically, we numerically calculate the shape of the capillary bridge between two contacting spheres that minimizes the total surface energy for a given volume and contact angle and compare to experiments. When the bridge is asymmetric, finite element calculations demonstrate that the shape of the bridge is spherical. In general, the bridge shape depends on both volume and contact angle, yet we find the degree of asymmetry is controlled by a single parameter.

  8. Novel absorption detection techniques for capillary electrophoresis

    SciTech Connect

    Xue, Yongjun

    1994-07-27

    Capillary electrophoresis (CE) has emerged as one of the most versatile separation methods. However, efficient separation is not sufficient unless coupled to adequate detection. The narrow inner diameter (I.D.) of the capillary column raises a big challenge to detection methods. For UV-vis absorption detection, the concentration sensitivity is only at the μM level. Most commercial CE instruments are equipped with incoherent UV-vis lamps. Low-brightness, instability and inefficient coupling of the light source with the capillary limit the further improvement of UV-vis absorption detection in CE. The goals of this research have been to show the utility of laser-based absorption detection. The approaches involve: on-column double-beam laser absorption detection and its application to the detection of small ions and proteins, and absorption detection with the bubble-shaped flow cell.

  9. Passive recruitment of circulating leukocytes into capillary sprouts from existing capillaries in a microfluidic system.

    PubMed

    Forouzan, Omid; Burns, Jennie M; Robichaux, Jennifer L; Murfee, Walter L; Shevkoplyas, Sergey S

    2011-06-07

    Recent evidence implicating leukocytes in angiogenesis raises the question of whether leukocytes and other cells circulating with the blood in microvascular networks can home to capillary sprouts intraluminally. This study describes an investigation of leukocyte trafficking in sprouting capillaries fabricated using soft lithography. The leukocytes passing with whole blood through existing capillaries were able to enter microfabricated capillary sprouts of variable length and sprouting angle due to the mechanical interaction with red blood cells (RBCs) at the sprouting bifurcation, in spite of the complete absence of blood flow through the blind-ended sprouts or any chemoattractants. The RBCs formed "comet tails" (the densely packed cellular trains forming behind leukocytes as they move through narrow capillaries) and effectively pushed leukocytes into the microfabricated sprouts while bypassing them at the sprouting bifurcation. Individual sprouts filled with several leukocytes, as wells as RBCs and platelets, were observed. The results of this study suggest that (i) blood cells are likely present in capillary sprouts throughout their development, (ii) leukocytes and other circulating cells may use this mechanism to home to capillary sprouts intraluminally for direct engraftment, and (iii) tissues may use this phenomenon as another mechanism for local recruitment of leukocytes from the blood stream.

  10. Photosensitive diazotized poly(ethylene glycol) covalent capillary coatings for analysis of proteins by capillary electrophoresis.

    PubMed

    Yu, Bing; Chen, Xin; Cong, Hailin; Shu, Xi; Peng, Qiaohong

    2016-09-01

    A new method for the fabrication of covalently cross-linked capillary coatings of poly(ethylene glycol) (PEG) is described using diazotized PEG (diazo-PEG) as a new photosensitive coating agent. The film of diazo-PEG depends on ionic bonding and was first prepared on the inner surface of capillary by self-assembly, and ionic bonding was converted into covalent bonding after reaction of ultraviolet light with diazo groups through unique photochemical reaction. The covalently bonded coating impedance adsorption of protein on the central surface of capillary and hence the four proteins ribonuclease A, cytochrome c, bovine serum albumin, and lysosome can be baseline separated by using capillary electrophoresis (CE). The covalently cross-linked diazo-PEG capillary column coatings not only improved the CE separation performance for proteins compared to non-covalently cross-linked coatings or bare capillary but also showed a remarkable chemical solidity and repeatability. Because photosensitive diazo-PEG took the place of the highly noxious and silane moisture-sensitive coating reagents in the fabrication of covalent coating, this technique shows the advantage of being environment-friendly and having a high efficiency for CE to make the covalently bonded capillaries.

  11. Approximate model for laser ablation of carbon

    NASA Astrophysics Data System (ADS)

    Shusser, Michael

    2010-08-01

    The paper presents an approximate kinetic theory model of ablation of carbon by a nanosecond laser pulse. The model approximates the process as sublimation and combines conduction heat transfer in the target with the gas dynamics of the ablated plume which are coupled through the boundary conditions at the interface. The ablated mass flux and the temperature of the ablating material are obtained from the assumption that the ablation rate is restricted by the kinetic theory limitation on the maximum mass flux that can be attained in a phase-change process. To account for non-uniform distribution of the laser intensity while keeping the calculation simple the quasi-one-dimensional approximation is used in both gas and solid phases. The results are compared with the predictions of the exact axisymmetric model that uses the conservation relations at the interface derived from the momentum solution of the Boltzmann equation for arbitrary strong evaporation. It is seen that the simpler approximate model provides good accuracy.

  12. Design Calculations for NIF Convergent Ablator Experiments

    NASA Astrophysics Data System (ADS)

    Olson, R. E.; Callahan, D. A.; Hicks, D. G.; Landen, O. L.; Langer, S. H.; Meezan, N. B.; Spears, B. K.; Widmann, K.; Kline, J. L.; Wilson, D. C.; Petrasso, R. D.; Leeper, R. J.

    2010-11-01

    Design calculations for NIF convergent ablator experiments will be described. The convergent ablator experiments measure the implosion trajectory, velocity, and ablation rate of an x-ray driven capsule and are a important component of the U. S. National Ignition Campaign at NIF. The design calculations are post-processed to provide simulations of the key diagnostics -- 1) Dante measurements of hohlraum x-ray flux and spectrum, 2) streaked radiographs of the imploding ablator shell, 3) wedge range filter measurements of D-He3 proton output spectra, and 4) GXD measurements of the imploded core. The simulated diagnostics will be compared to the experimental measurements to provide an assessment of the accuracy of the design code predictions of hohlraum radiation temperature, capsule ablation rate, implosion velocity, shock flash areal density, and x-ray bang time. Post-shot versions of the design calculations are used to enhance the understanding of the experimental measurements and will assist in choosing parameters for subsequent shots and the path towards optimal ignition capsule tuning. *SNL, LLNL, and LANL are operated under US DOE contracts DE-AC04-94AL85000. DE-AC52-07NA27344, and DE-AC04-94AL85000.

  13. Fracture in Phenolic Impregnated Carbon Ablator

    NASA Technical Reports Server (NTRS)

    Agrawal, Parul; Chavez-Garcia, Jose; Pham, John

    2013-01-01

    This paper describes the development of a novel technique to understand the failure mechanisms inside thermal protection materials. The focus of this research is on the class of materials known as phenolic impregnated carbon ablators. It has successfully flown on the Stardust spacecraft and is the thermal protection system material chosen for the Mars Science Laboratory and SpaceX Dragon spacecraft. Although it has good thermal properties, structurally, it is a weak material. To understand failure mechanisms in carbon ablators, fracture tests were performed on FiberForm(Registered TradeMark) (precursor), virgin, and charred ablator materials. Several samples of these materials were tested to investigate failure mechanisms at a microstructural scale. Stress-strain data were obtained simultaneously to estimate the tensile strength and toughness. It was observed that cracks initiated and grew in the FiberForm when a critical stress limit was reached such that the carbon fibers separated from the binder. However, both for virgin and charred carbon ablators, crack initiation and growth occurred in the matrix (phenolic) phase. Both virgin and charred carbon ablators showed greater strength values compared with FiberForm samples, confirming that the presence of the porous matrix helps in absorbing the fracture energy.

  14. GASEOUS DISCHARGE DEVICE

    DOEpatents

    Gow, J.D.

    1961-01-10

    An extremely compact two-terminal gaseous discharge device is described that is capable of producing neutrons in copious quantities, relatively high energy ions, intense x rays, and the like. Principal novelty resides in the provision of a crossed electric-magnetic field region in the discharge envelope that traps electrons and accelerates them to very high energies to provide an intense ionizing medium adjacent the anode of the device for ionizing gas therein with extremely high efficiency. In addition, the crossed-field trapping region holds the electrons close to the anode whereby the acceleration of ions to the cathode is not materially effected by the electron sheath and the ions assume substantially the full energy of the anodecathode potential drop. (auth)

  15. Chronic Atrial Fibrillation Ablation with Harmonic Scalpel during Mitral Valve Surgery

    PubMed Central

    Brick, Alexandre Visconti; Braile, Domingo M.

    2017-01-01

    Objective To evaluate surgical treatment of chronic atrial fibrillation with ultrasound in patients with mitral valve disease, considering preoperative clinical characteristics of patients undergoing surgical procedure and follow-up in the immediate postoperative period, in hospital and up to 60 months after discharge. Methods We studied 100 patients with chronic atrial fibrillation and mitral valve disease who underwent surgical treatment using ultrasound ablation. Patient data were reviewed by consulting the control reports, including signs and symptoms, underlying disease, functional class, hospital stay, surgical procedure time, ablation time, immediate complications, and complications at discharged and up to 60 months later. Actuarial curve (Kaplan-Meier) was used for the study of permanence without recurrence after 12, 24, 36, 48 and 60 months. Results 86% of the patients had rheumatic mitral valve disease, 14% had degeneration of the mitral valve, 40% had mitral regurgitation, and 36% had mitral stenosis. Main symptoms included palpitations related to tachycardia by chronic atrial fibrillation (70%), congestive heart failure (70%), and previous episodes of acute pulmonary edema (27%). Early results showed that 94% of the patients undergoing ultrasound ablation reversed the rate of chronic atrial fibrillation, 86% being in sinus rhythm and 8% in atrioventricular block. At hospital discharge, maintenance of sinus rhythm was observed in 86% of patients and there was recurrence of chronic atrial fibrillation in 8% of patients. At follow-up after 60 months, 83.8% of patients maintained the sinus rhythm. Conclusion Surgical treatment of chronic atrial fibrillation with ultrasound concomitant with mitral valve surgery is feasible and satisfactory, with maintenance of sinus rhythm in most patients (83.8%) after 60 months of follow-up.

  16. Internal electrolyte temperatures for polymer and fused-silica capillaries used in capillary electrophoresis.

    PubMed

    Evenhuis, Christopher J; Guijt, Rosanne M; Macka, Miroslav; Marriott, Philip J; Haddad, Paul R

    2005-11-01

    Polymers are important as materials for manufacturing microfluidic devices for electrodriven separations, in which Joule heating is an unavoidable phenomenon. Heating effects were investigated in polymer capillaries using a CE setup. This study is the first step toward the longer-term objective of the study of heating effects occurring in polymeric microfluidic devices. The thermal conductivity of polymers is much smaller than that of fused silica (FS), resulting in less efficient dissipation of heat in polymeric capillaries. This study used conductance measurements as a temperature probe to determine the mean electrolyte temperatures in CE capillaries of different materials. Values for mean electrolyte temperatures in capillaries made of New Generation FluoroPolymer (NGFP), poly-(methylmethacrylate) (PMMA), and poly(ether ether ketone) (PEEK) capillaries were compared with those obtained for FS capillaries. Extrapolation of plots of conductance versus power per unit length (P/L) to zero power was used to obtain conductance values free of Joule heating effects. The ratio of the measured conductance values at different power levels to the conductance at zero power was used to determine the mean temperature of the electrolyte. For each type of capillary material, it was found that the average increase in the mean temperature of the electrolyte (DeltaT(Mean)) was directly proportional to P/L and inversely proportional to the thermal conductivity (lambda) of the capillary material. At 7.5 W/m, values for DeltaT(Mean) for NGFP, PMMA, and PEEK were determined to be 36.6, 33.8, and 30.7 degrees C, respectively. Under identical conditions, DeltaT(Mean) for FS capillaries was 20.4 degrees C.

  17. Electrostatic discharge test apparatus

    NASA Technical Reports Server (NTRS)

    Smith, William Conrad (Inventor)

    1988-01-01

    Electrostatic discharge properties of materials are quantitatively measured and ranked. Samples are rotated on a turntable beneath selectable, co-available electrostatic chargers, one being a corona charging element and the other a sample-engaging triboelectric charging element. Samples then pass under a voltage meter to measure the amount of residual charge on the samples. After charging is discontinued, measurements are continued to record the charge decay history over time.

  18. Observation of gravity-capillary wave turbulence.

    PubMed

    Falcon, Eric; Laroche, Claude; Fauve, Stéphan

    2007-03-02

    We report the observation of the crossover between gravity and capillary wave turbulence on the surface of mercury. The probability density functions of the turbulent wave height are found to be asymmetric and thus non-Gaussian. The surface wave height displays power-law spectra in both regimes. In the capillary region, the exponent is in fair agreement with weak turbulence theory. In the gravity region, it depends on the forcing parameters. This can be related to the finite size of the container. In addition, the scaling of those spectra with the mean energy flux is found in disagreement with weak turbulence theory for both regimes.

  19. Capillary origami and superhydrophobic membrane surfaces

    NASA Astrophysics Data System (ADS)

    Geraldi, N. R.; Ouali, F. F.; Morris, R. H.; McHale, G.; Newton, M. I.

    2013-05-01

    Capillary origami uses surface tension to fold and shape solid films and membranes into three-dimensional structures. It uses the fact that solid surfaces, no matter how hydrophobic, will tend to adhere to and wrap around the surface of a liquid. In this work, we report that a superhydrophobic coating can be created, which can completely suppress wrapping as a contacting water droplet evaporates. We also show that using a wetting azeotropic solution of allyl alcohol, which penetrates the surface features, can enhance liquid adhesion and create more powerful Capillary Origami. These findings create the possibility of selectively shaping membrane substrates.

  20. Use of Plastic Capillaries for Macromolecular Crystallization

    NASA Technical Reports Server (NTRS)

    Potter, Rachel R.; Hong, Young-Soo; Ciszak, Ewa M.

    2003-01-01

    Methods of crystallization of biomolecules in plastic capillaries (Nalgene 870 PFA tubing) are presented. These crystallization methods used batch, free-interface liquid- liquid diffusion alone, or a combination with vapor diffusion. Results demonstrated growth of crystals of test proteins such as thaumatin and glucose isomerase, as well as protein studied in our laboratory such dihydrolipoamide dehydrogenase. Once the solutions were loaded in capillaries, they were stored in the tubes in frozen state at cryogenic temperatures until the desired time of activation of crystallization experiments.