Science.gov

Sample records for activation foils method

  1. Neutron Field Measurements in Phantom with Foil Activation Methods.

    DTIC Science & Technology

    1986-11-29

    jI25 Ii III uumu ullli~ S....- - Lb - w * .qJ’ AD-A 192 122 ulJ. IL (pj DNA-TR-87- 10 N EUTRON FIELD MEASUREMENTS IN PHANTOM WITH FOIL ACTIVATION...SAND II Measurements in Phantom 6 4 The 5-Foil Neutron Dosimetry Method 29 5 Comparison of SAND II and Simple 5-Foil Dosimetry Method 34 6 Thermal ...quite reasonable. The monkey phantom spectrum differs from the NBS U-235 fission spectrum in that the former has a I/E tail plus thermal -neutron peak

  2. Method for fabricating uranium foils and uranium alloy foils

    DOEpatents

    Hofman, Gerard L.; Meyer, Mitchell K.; Knighton, Gaven C.; Clark, Curtis R.

    2006-09-05

    A method of producing thin foils of uranium or an alloy. The uranium or alloy is cast as a plate or sheet having a thickness less than about 5 mm and thereafter cold rolled in one or more passes at substantially ambient temperatures until the uranium or alloy thereof is in the shape of a foil having a thickness less than about 1.0 mm. The uranium alloy includes one or more of Zr, Nb, Mo, Cr, Fe, Si, Ni, Cu or Al.

  3. Characterization of the CALIBAN Critical Assembly Neutron Spectra using Several Adjustment Methods Based on Activation Foils Measurement

    NASA Astrophysics Data System (ADS)

    Casoli, Pierre; Grégoire, Gilles; Rousseau, Guillaume; Jacquet, Xavier; Authier, Nicolas

    2016-02-01

    CALIBAN is a metallic critical assembly managed by the Criticality, Neutron Science and Measurement Department located on the French CEA Center of Valduc. The reactor is extensively used for benchmark experiments dedicated to the evaluation of nuclear data, for electronic hardening or to study the effect of the neutrons on various materials. Therefore CALIBAN irradiation characteristics and especially its central cavity neutron spectrum have to be very accurately evaluated. In order to strengthen our knowledge of this spectrum, several adjustment methods based on activation foils measurements are being studied for a few years in the laboratory. Firstly two codes included in the UMG package have been tested and compared: MAXED and GRAVEL. More recently, the CALIBAN cavity spectrum has been studied using CALMAR, a new adjustment tool currently under development at the CEA Center of Cadarache. The article will discuss and compare the results and the quality of spectrum rebuilding obtained with the UMG codes and with the CALMAR software, from a set of activation measurements carried out in the CALIBAN irradiation cavity.

  4. Method of high-density foil fabrication

    DOEpatents

    Blue, Craig A.; Sikka, Vinod K.; Ohriner, Evan K.

    2003-12-16

    A method for preparing flat foils having a high density includes the steps of mixing a powdered material with a binder to form a green sheet. The green sheet is exposed to a high intensity radiative source adapted to emit radiation of wavelengths corresponding to an absorption spectrum of the powdered material. The surface of the green sheet is heated while a lower sub-surface temperature is maintained. An apparatus for preparing a foil from a green sheet using a radiation source is also disclosed.

  5. Method of forming a thin unbacked metal foil

    DOEpatents

    Duchane, David V.; Barthell, Barry L.

    1984-01-01

    In a method of forming a thin (<2 .mu.m) unbacked metal foil having a desired curviplanar shape, a soluble polymeric film, preferably comprising polyvinyl alcohol, is formed on a supporting structure having a shape that defines the desired shape of the foil product. A layer of metal foil is deposited onto one side of the soluble film, preferably by vacuum vapor deposition. The metallized film is then immersed in a suitable solvent to dissolve the film and thereby leave the metal foil as an unbacked metal foil element mounted on the supporting structure. Aluminum foils less than 0.2 .mu.m (2,000 .ANG.) thick and having an areal density of less than 54 .mu.g/cm.sup.2 have been obtained.

  6. Method of fabricating a uranium-bearing foil

    DOEpatents

    Gooch, Jackie G [Seymour, TN; DeMint, Amy L [Kingston, TN

    2012-04-24

    Methods of fabricating a uranium-bearing foil are described. The foil may be substantially pure uranium, or may be a uranium alloy such as a uranium-molybdenum alloy. The method typically includes a series of hot rolling operations on a cast plate material to form a thin sheet. These hot rolling operations are typically performed using a process where each pass reduces the thickness of the plate by a substantially constant percentage. The sheet is typically then annealed and then cooled. The process typically concludes with a series of cold rolling passes where each pass reduces the thickness of the plate by a substantially constant thickness amount to form the foil.

  7. Method for laser welding ultra-thin metal foils

    DOEpatents

    Pernicka, J.C.; Benson, D.K.; Tracy, C.E.

    1996-03-26

    A method for simultaneously cutting and welding ultra-thin foils having a thickness of less than 0.002 inches wherein two ultra-thin films are stacked and clamped together. A pulsed laser such as of the Neodymium: YAG type is provided and the beam of the laser is directed onto the stacked films to cut a channel through the films. The laser is moved relative to the stacked foils to cut the stacked foils at successive locations and to form a plurality of connected weld beads to form a continuous weld. 5 figs.

  8. Method for laser welding ultra-thin metal foils

    DOEpatents

    Pernicka, John C.; Benson, David K.; Tracy, C. Edwin

    1996-01-01

    A method for simultaneously cutting and welding ultra-thin foils having a thickness of less than 0.002 inches wherein two ultra-thin films are stacked and clamped together. A pulsed laser such as of the Neodymium: YAG type is provided and the beam of the laser is directed onto the stacked films to cut a channel through the films. The laser is moved relative to the stacked foils to cut the stacked foils at successive locations and to form a plurality of connected weld beads to form a continuous weld.

  9. Characterization of AN Actively Cooled Metal Foil Thermal Radiation Shield

    NASA Astrophysics Data System (ADS)

    Feller, J. R.; Kashani, A.; Helvensteijn, B. P. M.; Salerno, L. J.

    2010-04-01

    Zero boil-off (ZBO) or reduced boil-off (RBO) systems that involve active cooling of large cryogenic propellant tanks will most likely be required for future space exploration missions. For liquid oxygen or methane, such systems could be implemented using existing high technology readiness level (TRL) cryocoolers. However, for liquid hydrogen temperatures (˜20 K) no such coolers exist. In order to partially circumvent this technology gap, the concept of broad area cooling (BAC) has been developed, whereby a low mass thermal radiation shield could be maintained at temperatures around 100 K by steady circulation of cold pressurized gas through a network of narrow tubes. By this method it is possible to dramatically reduce the radiative heat leak to the 20 K tank. A series of experiments, designed to investigate the heat transfer capabilities of BAC systems, have been conducted at NASA Ames Research Center (ARC). Results of the final experiment in this series, investigating heat transfer from a metal foil film to a distributed cooling line, are presented here.

  10. CHARACTERIZATION OF AN ACTIVELY COOLED METAL FOIL THERMAL RADIATION SHIELD

    SciTech Connect

    Feller, J. R.; Salerno, L. J.; Kashani, A.; Helvensteijn, B. P. M.

    2010-04-09

    Zero boil-off (ZBO) or reduced boil-off (RBO) systems that involve active cooling of large cryogenic propellant tanks will most likely be required for future space exploration missions. For liquid oxygen or methane, such systems could be implemented using existing high technology readiness level (TRL) cryocoolers. However, for liquid hydrogen temperatures (approx20 K) no such coolers exist. In order to partially circumvent this technology gap, the concept of broad area cooling (BAC) has been developed, whereby a low mass thermal radiation shield could be maintained at temperatures around 100 K by steady circulation of cold pressurized gas through a network of narrow tubes. By this method it is possible to dramatically reduce the radiative heat leak to the 20 K tank. A series of experiments, designed to investigate the heat transfer capabilities of BAC systems, have been conducted at NASA Ames Research Center (ARC). Results of the final experiment in this series, investigating heat transfer from a metal foil film to a distributed cooling line, are presented here.

  11. A simple method for the measurement of reflective foil emissivity

    NASA Astrophysics Data System (ADS)

    Ballico, M. J.; van der Ham, E. W. M.

    2013-09-01

    Reflective metal foil is widely used to reduce radiative heat transfer within the roof space of buildings. Such foils are typically mass-produced by vapor-deposition of a thin metallic coating onto a variety of substrates, ranging from plastic-coated reinforced paper to "bubble-wrap". Although the emissivity of such surfaces is almost negligible in the thermal infrared, typically less than 0.03, an insufficiently thick metal coating, or organic contamination of the surface, can significantly increase this value. To ensure that the quality of the installed insulation is satisfactory, Australian building code AS/NZS 4201.5:1994 requires a practical agreed method for measurement of the emissivity, and the standard ASTM-E408 is implied. Unfortunately this standard is not a "primary method" and requires the use of specified expensive apparatus and calibrated reference materials. At NMIA we have developed a simple primary technique, based on an apparatus to thermally modulate the sample and record the apparent modulation in infra-red radiance with commercially available radiation thermometers. The method achieves an absolute accuracy in the emissivity of approximately 0.004 (k=2). This paper theoretically analyses the equivalence between the thermal emissivity measured in this manner, the effective thermal emissivity in application, and the apparent emissivity measured in accordance with ASTM-E408.

  12. A simple method for the measurement of reflective foil emissivity

    SciTech Connect

    Ballico, M. J.; Ham, E. W. M. van der

    2013-09-11

    Reflective metal foil is widely used to reduce radiative heat transfer within the roof space of buildings. Such foils are typically mass-produced by vapor-deposition of a thin metallic coating onto a variety of substrates, ranging from plastic-coated reinforced paper to 'bubble-wrap'. Although the emissivity of such surfaces is almost negligible in the thermal infrared, typically less than 0.03, an insufficiently thick metal coating, or organic contamination of the surface, can significantly increase this value. To ensure that the quality of the installed insulation is satisfactory, Australian building code AS/NZS 4201.5:1994 requires a practical agreed method for measurement of the emissivity, and the standard ASTM-E408 is implied. Unfortunately this standard is not a 'primary method' and requires the use of specified expensive apparatus and calibrated reference materials. At NMIA we have developed a simple primary technique, based on an apparatus to thermally modulate the sample and record the apparent modulation in infra-red radiance with commercially available radiation thermometers. The method achieves an absolute accuracy in the emissivity of approximately 0.004 (k=2). This paper theoretically analyses the equivalence between the thermal emissivity measured in this manner, the effective thermal emissivity in application, and the apparent emissivity measured in accordance with ASTM-E408.

  13. Methods of making metallic glass foil laminate composites

    DOEpatents

    Vianco, P.T.; Fisher, R.W.; Hosking, F.M.; Zanner, F.J.

    1996-08-20

    A process for the fabrication of a rapidly solidified foil laminate composite. An amorphous metallic glass foil is flux treated and coated with solder. Before solidification of the solder the foil is collected on a take-up spool which forms the composite into a solid annular configuration. The resulting composite exhibits high strength, resiliency and favorable magnetic and electrical properties associated with amorphous materials. The composite also exhibits bonding strength between the foil layers which significantly exceeds the bulk strength of the solder alone. 6 figs.

  14. Methods of making metallic glass foil laminate composites

    DOEpatents

    Vianco, Paul T.; Fisher, Robert W.; Hosking, Floyd M.; Zanner, Frank J.

    1996-01-01

    A process for the fabrication of a rapidly solidified foil laminate composite. An amorphous metallic glass foil is flux treated and coated with solder. Before solidification of the solder the foil is collected on a take-up spool which forms the composite into a solid annular configuration. The resulting composite exhibits high strength, resiliency and favorable magnetic and electrical properties associated with amorphous materials. The composite also exhibits bonding strength between the foil layers which significantly exceeds the bulk strength of the solder alone.

  15. Tubular hydrogen permeable metal foil membrane and method of fabrication

    DOEpatents

    Paglieri, Stephen N.; Birdsell, Stephen A.; Barbero, Robert S.; Snow, Ronny C.; Smith, Frank M.

    2006-04-04

    A tubular hydrogen permeable metal membrane and fabrication process comprises obtaining a metal alloy foil having two surfaces, coating the surfaces with a metal or metal alloy catalytic layer to produce a hydrogen permeable metal membrane, sizing the membrane into a sheet with two long edges, wrapping the membrane around an elongated expandable rod with the two long edges aligned and overlapping to facilitate welding of the two together, placing the foil wrapped rod into a surrounding fixture housing with the two aligned and overlapping foil edges accessible through an elongated aperture in the surrounding fixture housing, expanding the elongated expandable rod within the surrounding fixture housing to tighten the foil about the expanded rod, welding the two long overlapping foil edges to one another generating a tubular membrane, and removing the tubular membrane from within the surrounding fixture housing and the expandable rod from with the tubular membrane.

  16. Pu-ZR Alloy high-temperature activation-measurement foil

    DOEpatents

    McCuaig, Franklin D.

    1977-08-02

    A nuclear reactor fuel alloy consists essentially of from slightly greater than 7 to about 4 w/o zirconium, balance plutonium, and is characterized in that the alloy is castable and is rollable to thin foils. A preferred embodiment of about 7 w/o zirconium, balance plutonium, has a melting point substantially above the melting point of plutonium, is rollable to foils as thin as 0.0005 inch thick, and is compatible with cladding material when repeatedly cycled to temperatures above 650.degree. C. Neutron flux densities across a reactor core can be determined with a high-temperature activation-measurement foil which consists of a fuel alloy foil core sandwiched and sealed between two cladding material jackets, the fuel alloy foil core being a 7 w/o zirconium, plutonium foil which is from 0.005 to 0.0005 inch thick.

  17. SU-E-T-557: Measuring Neutron Activation of Cardiac Devices Irradiated During Proton Therapy Using Indium Foils

    SciTech Connect

    Avery, S; Christodouleas, J; Delaney, K; Diffenderfer, E; Brown, K

    2014-06-01

    Purpose: Measuring Neutron Activation of Cardiac devices Irradiated during Proton Therapy using Indium Foils Methods: The foils had dimensions of 25mm x 25mm x 1mm. After being activated, the foils were placed in a Canberra Industries well chamber utilizing a NaI(Tl) scintillation detector. The resulting gamma spectrum was acquired and analyzed using Genie 2000 spectroscopy software. One activation foil was placed over the upper, left chest of RANDO where a pacemaker would be. The rest of the foils were placed over the midline of the patient at different distances, providing a spatial distribution over the phantom. Using lasers and BBs to align the patient, 200 MU square fields were delivered to various treatment sites: the brain, the pancreas, and the prostate. Each field was shot at least a day apart, giving more than enough time for activity of the foil to decay (t1=2 = 54.12 min). Results: The net counts (minus background) of the three aforementioned peaks were used for our measurements. These counts were adjusted to account for detector efficiency, relative photon yields from decay, and the natural abundance of 115-In. The average neutron flux for the closed multi-leaf collimator irradiation was measured to be 1.62 x 106 - 0.18 x 106 cm2 s-1. An order of magnitude estimate of the flux for neutrons up to 1 keV from Diffenderfer et al. gives 3 x 106 cm2 s-1 which does agree on the order of magnitude. Conclusion: Lower energy neutrons have higher interaction cross-sections and are more likely to damage pacemakers. The thermal/slow neutron component may be enough to estimate the overall risk. The true test of the applicability of activation foils is whether or not measurements are capable of predicting cardiac device malfunction. For that, additional studies are needed to provide clinical evidence one way or the other.

  18. Classroom Foils

    ERIC Educational Resources Information Center

    Pafford, William N.

    1970-01-01

    Aluminum foil, because of its characteristics, can be used for many elementary science activities: demonstrating Archimedes Principle, how to reduce cohesion, reflection and mirror effect, fuse action, condensation, friction, and as containers and barriers. (BR)

  19. Method of using deuterium-cluster foils for an intense pulsed neutron source

    DOEpatents

    Miley, George H.; Yang, Xiaoling

    2013-09-03

    A method is provided for producing neutrons, comprising: providing a converter foil comprising deuterium clusters; focusing a laser on the foil with power and energy sufficient to cause deuteron ions to separate from the foil; and striking a surface of a target with the deuteron ions from the converter foil with energy sufficient to cause neutron production by a reaction selected from the group consisting of D-D fusion, D-T fusion, D-metal nuclear spallation, and p-metal. A further method is provided for assembling a plurality of target assemblies for a target injector to be used in the previously mentioned manner. A further method is provided for producing neutrons, comprising: splitting a laser beam into a first beam and a second beam; striking a first surface of a target with the first beam, and an opposite second surface of the target with the second beam with energy sufficient to cause neutron production.

  20. An Innovative Method for Manufacturing Gamma-TiAl Foil

    NASA Technical Reports Server (NTRS)

    Hales, Stephen J.; Saqib, Mohammad; Alexa, Joel A.

    2003-01-01

    The manufacture and entrance into service of thin gage gamma-TiAl product has been hampered by the inherent low room temperature ductility of the material. In the present study a new approach was explored for the efficient manufacture of gamma-TiAl foil with improved ductility. The objective was to produce a very clean material (low interstitial content) with a highly refined, homogeneous microstructure placed in a fully lamellar condition. The processing route involved the use of RF plasma spray deposition of pre-alloyed powders, followed by consolidation via vacuum hot pressing and heat treatment. The approach took advantage of a deposition process which included no electrodes, no binders and high cooling rates. Results and discussion of the work performed to date are presented.

  1. Thin Foil Acceleration Method for Measuring the Unloading Isentropes of Shock-Compressed Matter

    SciTech Connect

    Asay, J.R.; Chhabildas, L.C.; Fortov, V.E.; Kanel, G.I.; Khishchenko, K.V.; Lomonosov, I.V.; Mehlhorn, T.; Razorenov, S.V.; Utkin, A.V.

    1999-07-21

    This work has been performed as part of the search for possible ways to utilize the capabilities of laser and particle beams techniques in shock wave and equation of state physics. The peculiarity of these techniques is that we have to deal with micron-thick targets and not well reproducible incident shock wave parameters, so all measurements should be of a high resolution and be done in one shot. Besides the Hugoniots, the experimental basis for creating the equations of state includes isentropes corresponding to unloading of shock-compressed matter. Experimental isentrope data are most important in the region of vaporization. With guns or explosive facilities, the unloading isentrope is recovered from a series of experiments where the shock wave parameters in plates of standard low-impedance materials placed behind the sample are measured [1,2]. The specific internal energy and specific volume are calculated from the measured p(u) release curve which corresponds to the Riemann integral. This way is not quite suitable for experiments with beam techniques where the incident shock waves are not well reproducible. The thick foil method [3] provides a few experimental points on the isentrope in one shot. When a higher shock impedance foil is placed on the surface of the material studied, the release phase occurs by steps, whose durations correspond to that for the shock wave to go back and forth in the foil. The velocity during the different steps, connected with the knowledge of the Hugoniot of the foil, allows us to determine a few points on the isentropic unloading curve. However, the method becomes insensitive when the low pressure range of vaporization is reached in the course of the unloading. The isentrope in this region can be measured by recording the smooth acceleration of a thin witness plate foil. With the mass of the foil known, measurements of the foil acceleration will give us the vapor pressure.

  2. Validation of MCNP NPP Activation Simulations for Decommissioning Studies by Analysis of NPP Neutron Activation Foil Measurement Campaigns

    NASA Astrophysics Data System (ADS)

    Volmert, Ben; Pantelias, Manuel; Mutnuru, R. K.; Neukaeter, Erwin; Bitterli, Beat

    2016-02-01

    In this paper, an overview of the Swiss Nuclear Power Plant (NPP) activation methodology is presented and the work towards its validation by in-situ NPP foil irradiation campaigns is outlined. Nuclear Research and consultancy Group (NRG) in The Netherlands has been given the task of performing the corresponding neutron metrology. For this purpose, small Aluminium boxes containing a set of circular-shaped neutron activation foils have been prepared. After being irradiated for one complete reactor cycle, the sets have been successfully retrieved, followed by gamma-spectrometric measurements of the individual foils at NRG. Along with the individual activities of the foils, the reaction rates and thermal, intermediate and fast neutron fluence rates at the foil locations have been determined. These determinations include appropriate corrections for gamma self-absorption and neutron self-shielding as well as corresponding measurement uncertainties. The comparison of the NPP Monte Carlo calculations with the results of the foil measurements is done by using an individual generic MCNP model functioning as an interface and allowing the simulation of individual foil activation by predetermined neutron spectra. To summarize, the comparison between calculation and measurement serve as a sound validation of the Swiss NPP activation methodology by demonstrating a satisfying agreement between measurement and calculation. Finally, the validation offers a chance for further improvements of the existing NPP models by ensuing calibration and/or modelling optimizations for key components and structures.

  3. 78 FR 28577 - Notification of Proposed Production Activity, LLFlex, LLC, Subzone 29J (Foil Backed Paperboard...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-15

    ... Foreign-Trade Zones Board Notification of Proposed Production Activity, LLFlex, LLC, Subzone 29J (Foil... notification of proposed production activity to the FTZ Board for its facility located in Louisville, Kentucky... subsequently authorized by the FTZ Board. Production under FTZ procedures could exempt LLFlex from customs...

  4. Method of making porous conductive supports for electrodes. [by electroforming and stacking nickel foils

    NASA Technical Reports Server (NTRS)

    Schaer, G. R. (Inventor)

    1973-01-01

    Porous conductive supports for electrochemical cell electrodes are made by electroforming thin corrugated nickel foil, and by stacking pieces of the corrugated foil alternatively with pieces of thin flat nickel foil. Corrugations in successive corrugated pieces are oriented at different angles. Adjacent pieces of foil are bonded by heating in a hydrogen atmosphere and then cutting the stack in planes perpendicular to the foils.

  5. Antimicrobial activities of CuO films deposited on Cu foils by solution chemistry

    NASA Astrophysics Data System (ADS)

    Ekthammathat, Nuengruethai; Thongtem, Titipun; Thongtem, Somchai

    2013-07-01

    Monoclinic CuO thin films on Cu foils were successfully synthesized by a simple wet chemical method in alkaline solution with the pH of 13 at room temperature for different lengths of time. The as-synthesized thin films were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and selected area electron diffraction (SAED). Formation mechanism of the phase and morphologies was also discussed according to the experimental results. In this research, assemblies of pure CuO nanospindles with different orientations containing in the thin film synthesized for 2 weeks with 400 nm and 413 nm violet emissions showed better antimicrobial activity against S. aureus than E. coli.

  6. Unfolding neutron energy spectra from foil activation detector measurements with the Gold algorithm

    NASA Astrophysics Data System (ADS)

    Seghour, A.; Seghour, F. Z.

    2001-01-01

    In this work, the Gold algorithm is applied to the unfolding of neutron reactor energy spectra from reaction rates data of multiple foil activation detectors. Such a method, which forms the basis of a developed unfolding computer program called SAYD, has the advantage of not requiring a priori knowledge on the spectrum in the unfolding process. The program SAYD is first illustrated by synthesized reaction rates data calculated using a semi-empirical formulation of a typical intermediate and fast neutron reactor spectrum. The demonstration of the unfolding program SAYD is next achieved using measured reaction rates of the Arkansas Nuclear One power plant (ANO) benchmark spectrum by comparing results of SAYD program with those obtained by STAYNL and MSANDB unfolding codes.

  7. A new method for designing dual foil electron beam forming systems. I. Introduction, concept of the method

    NASA Astrophysics Data System (ADS)

    Adrich, Przemysław

    2016-05-01

    In Part I of this work existing methods and problems in dual foil electron beam forming system design are presented. On this basis, a new method of designing these systems is introduced. The motivation behind this work is to eliminate the shortcomings of the existing design methods and improve overall efficiency of the dual foil design process. The existing methods are based on approximate analytical models applied in an unrealistically simplified geometry. Designing a dual foil system with these methods is a rather labor intensive task as corrections to account for the effects not included in the analytical models have to be calculated separately and accounted for in an iterative procedure. To eliminate these drawbacks, the new design method is based entirely on Monte Carlo modeling in a realistic geometry and using physics models that include all relevant processes. In our approach, an optimal configuration of the dual foil system is found by means of a systematic, automatized scan of the system performance in function of parameters of the foils. The new method, while being computationally intensive, minimizes the involvement of the designer and considerably shortens the overall design time. The results are of high quality as all the relevant physics and geometry details are naturally accounted for. To demonstrate the feasibility of practical implementation of the new method, specialized software tools were developed and applied to solve a real life design problem, as described in Part II of this work.

  8. Modified titanium foil's surface by high temperature carbon sintering method as the substrate for bipolar lead-acid battery

    NASA Astrophysics Data System (ADS)

    Lang, Xiaoshi; Wang, Dianlong; Zhu, Junsheng

    2014-12-01

    Titanium foil can be a type of ideal material as the substrate for bipolar lead-acid battery. However, it can't be directly used because it can be oxidized in the high voltage and strong oxidizing conditions. In this paper, we coat the titanium suboxide on the titanium foil surface by means of the high temperature carbon sintering method for the improvement of corrosion resistance of titanium metal and use it as the substrate to bipolar lead-acid battery to study its effect on the battery performances. Modified titanium foils are characterized by SEM, XRD, corrosion resistance test and electronic conductivity test. The electrochemical properties of the bipolar lead-acid battery are investigated by constant current charge/discharge method. The results demonstrate that the titanium foil carbon-sintered at 800 °C for 2 h has the most excellent chemical stability and electronic conductivity. Initial specific capacities of positive active material of bipolar lead-acid battery with modified titanium as the substrate at 0.25C, 0.5C, 1C and 2C discharge rate are 99.29 mAh g-1, 88.93 mAh g-1, 77.54 mAh g-1, and 65.41 mAh g-1. After 50 cycles, the specific capacity of positive active material at 0.5C is 81.36 mAh g-1 and after 100 cycles, the specific capacity at 1C is 61.92 mAh g-1.

  9. Neutron energy spectra unfolding from foil activation detector measurements with MINUIT

    NASA Astrophysics Data System (ADS)

    Seghour, A.; Seghour, F. Z.

    2005-12-01

    A method for unfolding neutron energy spectra from foil activation measurements using the multiparameter function minimisation routine MINUIT of Cernlib has been developed. It is based on the expansion of the neutron energy distribution on a set of parameters that are fitted to minimise the square sum of differences between the measured and calculated activities under smoothness and shape constraints. A modified square sum of differences expression weighted by each activation detector response contribution over the whole neutron energy range is proposed and compared with the classical square sum formulation. The proposed unfolding procedure is first illustrated by a set of 15 detectors to simulate reaction rates calculated using a typical neutron reactor energy spectrum. The demonstration of the proposed method is next achieved using measured reaction rates of the Arkansas Nuclear One power plant (ANO) benchmark spectrum of the Neutron Metrology File (NMF-90). Results of the proposed method were compared with those obtained by STAYNL and MSANDB unfolding codes using the same input data and were found in good agreement with the measured activities. The developed procedure is found to have an interesting advantage in unfolding neutron energy distribution in cases of a lack of information on the a priori solution. This has been illustrated by unfolding the JOYO MK-II fast breeder reactor neutron spectrum, using a set of experimental activation rates without a guess solution.

  10. 78 FR 55057 - Subzone 29J, Authorization of Production Activity, LLFlex, LLC; (Foil Backed Paperboard...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-09

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE Foreign-Trade Zones Board Subzone 29J, Authorization of Production Activity, LLFlex, LLC; (Foil Backed Paperboard), Louisville, Kentucky On May 6, 2013, LLFlex, LLC submitted a notification of proposed...

  11. Validating the method of pressure sensing to optimize flapping foil energy extraction

    NASA Astrophysics Data System (ADS)

    Persichetti, Amanda J.

    Renewable energy resources are in high demand due to a world-wide desire for cleaner energy production. Flapping foil tidal driven systems have begun being tested and implemented at prototype scales. These prototype systems use limited control to maximize energy production. This thesis uses biological inspiration from the sensory system in fish to enhance the efficiency of these energy harnessing systems with the use of surface mounted pressure sensing. Eight pressure sensors were found to be a good balance for quantity with respect to cost and accuracy. Optimal locations around the foil were determined from application of a Random Search algorithm and a fluid moment approximation. A 2-D numerical code was created to simulate a NACA0015 flapping foil in uniform potential flow. A wide parameter space of sinusoidal heave and pitch motions was run and a database of force, pressure, and efficiency values along with flow visualization was built. An efficiency of 0.43 was reached for the trajectory of motion with a pitch amplitude of 90 degrees, heave amplitude of 1.25 and a Strouhal number of 0.5. A control platform dependent on pressure measurements at the eight sensor locations was created in the 2-D numerical code. By implementing basic control, motion trajectories converge to the optimal motion based on pressure comparisons around the foil to pressure traces from the motion with highest efficiency. In addition, a laboratory for experimental testing and validation was set-up. The motion control system was connected and tested for a tow tank set-up. Motion programs were written for the same parameter space modeled in this thesis. Through numerical modeling, pressure sensing was found to be an effective method to enhancing the efficiency of a flapping foil energy extraction system.

  12. DEVELOPMENT OF MANUFACTURING METHODS FOR LIGHTWEIGHT METAL FOIL HEAT EXCHANGERS.

    DTIC Science & Technology

    MICROSTRUCTURE, TENSILE PROPERTIES, STRESSES, SPOT WELDS, COATINGS , SILICIDES , OXIDATION, TEST METHODS....PHOSPHORUS ALLOYS, ALUMINUM ALLOYS, NIOBIUM ALLOYS, PRESSURE, THERMAL JOINING, AEROSPACE CRAFT, DIFFUSION, BONDING, VACUUM FURNACES, SOLDERED JOINTS

  13. Foil Artists

    ERIC Educational Resources Information Center

    Szekely, George

    2010-01-01

    Foil can be shaped into almost anything--it is the all-purpose material for children's art. Foil is a unique drawing surface. It reflects, distorts and plays with light and imagery as young artists draw over it. Foil permits quick impressions of a model or object to be sketched. Foil allows artists to track their drawing moves, seeing the action…

  14. A Multi-Point Measurement Method for Thermal Characterization of Foil Bearings Using Customized Thermocouples

    NASA Astrophysics Data System (ADS)

    Lubieniecki, Michał; Roemer, Jakub; Martowicz, Adam; Wojciechowski, Krzysztof; Uhl, Tadeusz

    2016-03-01

    Gas foil bearings have become widespread covering the applications of micro-turbines, motors, compressors, and turbocharges, prevalently of small size. The specific construction of the bearing, despite all of its advantages, makes it vulnerable to a local difference in heat generation rates that can be extremely detrimental. The developing thermal gradients may lead to thermal runaway or seizure that eventually causes bearing failure, usually abrupt in nature. The authors propose a method for thermal gradient removal with the use of current-controlled thermoelectric modules. To fulfill the task of control law adoption the numerical model of the heat distribution in a bearing has been built. Although sparse readings obtained experimentally with standard thermocouples are enough to determine thermal gradients successfully, validation of the bearing numerical model may be impeded. To improve spatial resolution of the experimental measurements the authors proposed a matrix of customized thermocouples located on the top foil. The foil acts as a shared conductor for each thermocouple that reduces the number of cable connections. The proof of concept of the control and measurement systems has been demonstrated in a still bearing heated by a cartridge heater.

  15. Neutron intensity monitor with activation foil for p-Li neutron source for BNCT--Feasibility test of the concept.

    PubMed

    Murata, Isao; Otani, Yuki; Sato, Fuminobu

    2015-12-01

    Proton-lithium (p-Li) reaction is being examined worldwide as a candidate nuclear production reaction for accelerator based neutron source (ABNS) for BNCT. In this reaction, the emitted neutron energy is not so high, below 1 MeV, and especially in backward angles the energy is as low as about 100 keV. The intensity measurement was thus known to be difficult so far. In the present study, a simple method was investigated to monitor the absolute neutron intensity of the p-Li neutron source by employing the foil activation method based on isomer production reactions in order to cover around several hundreds keV. As a result of numerical examination, it was found that (107)Ag, (115)In and (189)Os would be feasible. Their features found out are summarized as follows: (107)Ag: The most convenient foil, since the half life is short. (115)In: The accuracy is the best at 0°, though it cannot be used for backward angles. And (189)Os: Suitable nuclide which can be used in backward angles, though the gamma-ray energy is a little too low. These would be used for p-Li source monitoring depending on measuring purposes in real BNCT scenes.

  16. High fidelity studies of exploding foil initiator bridges, Part 1: Experimental method

    NASA Astrophysics Data System (ADS)

    Bowden, Mike; Neal, William

    2017-01-01

    Simulations of high voltage detonators, such as Exploding Bridgewire (EBW) and Exploding Foil Initiators (EFI), have historically been simple, often empirical, one-dimensional models capable of predicting parameters such as current, voltage and in the case of EFIs, flyer velocity. Correspondingly, experimental methods have in general been limited to the same parameters. With the advent of complex, first principles magnetohydrodynamic codes such as ALEGRA and ALE-MHD, it is now possible to simulate these components in three dimensions, predicting a much greater range of parameters than before. A significant improvement in experimental capability was therefore required to ensure these simulations could be adequately validated. In this first paper of a three part study, the experimental method for determining the current, voltage, flyer velocity and multi-dimensional profile of detonator components is presented. This improved capability, along with high fidelity simulations, offer an opportunity to gain a greater understanding of the processes behind the functioning of EBW and EFI detonators.

  17. A new method for designing dual foil electron beam forming systems. II. Feasibility of practical implementation of the method

    NASA Astrophysics Data System (ADS)

    Adrich, Przemysław

    2016-05-01

    In Part I of this work a new method for designing dual foil electron beam forming systems was introduced. In this method, an optimal configuration of the dual foil system is found by means of a systematic, automatized scan of system performance in function of its parameters. At each point of the scan, Monte Carlo method is used to calculate the off-axis dose profile in water taking into account detailed and complete geometry of the system. The new method, while being computationally intensive, minimizes the involvement of the designer. In this Part II paper, feasibility of practical implementation of the new method is demonstrated. For this, a prototype software tools were developed and applied to solve a real life design problem. It is demonstrated that system optimization can be completed within few hours time using rather moderate computing resources. It is also demonstrated that, perhaps for the first time, the designer can gain deep insight into system behavior, such that the construction can be simultaneously optimized in respect to a number of functional characteristics besides the flatness of the off-axis dose profile. In the presented example, the system is optimized in respect to both, flatness of the off-axis dose profile and the beam transmission. A number of practical issues related to application of the new method as well as its possible extensions are discussed.

  18. Eddy current probe with foil sensor mounted on flexible probe tip and method of use

    DOEpatents

    Viertl, John R. M.; Lee, Martin K.

    2001-01-01

    A pair of copper coils are embedded in the foil strip. A first coil of the pair generates an electromagnetic field that induces eddy currents on the surface, and the second coil carries a current influenced by the eddy currents on the surface. The currents in the second coil are analyzed to obtain information on the surface eddy currents. An eddy current probe has a metal housing having a tip that is covered by a flexible conductive foil strip. The foil strip is mounted on a deformable nose at the probe tip so that the strip and coils will conform to the surface to which they are applied.

  19. Method to Increase Performance of Foil Bearings Through Passive Thermal Management

    NASA Technical Reports Server (NTRS)

    Bruckner, Robert

    2013-01-01

    This invention is a new approach to designing foil bearings to increase their load capacity and improve their reliability through passive thermal management. In the present case, the bearing is designed in such a way as to prevent the carryover of lubricant from the exit of one sector to the inlet of the ensuing sector of the foil bearing. When such passive thermal management techniques are used, bearing load capacity is improved by multiples, and reliability is enhanced when compared to current foil bearings. This concept has recently been tested and validated, and shows that load capacity performance of foil bearings can be improved by a factor of two at relatively low speeds with potentially greater relative improvements at higher speeds. Such improvements in performance with respect to speed are typical of foil bearings. Additionally, operation of these newly conceived bearings shows much more reliability and repeatable performance. This trait can be exploited in machine design to enhance safety, reliability, and overall performance. Finally, lower frictional torque has been demonstrated when operating at lower (non-load capacity) loads, thus providing another improvement above the current state of the art. The objective of the invention is to incorporate features into a foil bearing that both enhance passive thermal management and temperature control, while at the same time improve the hydrodynamic (load capacity) performance of the foil bearing. Foil bearings are unique antifriction devices that can utilize the working fluid of a machine as a lubricant (typically air for turbines and motors, liquids for pumps), and as a coolant to remove excess energy due to frictional heating. The current state of the art of foil bearings utilizes forced cooling of the bearing and shaft, which represents poor efficiency and poor reliability. This invention embodies features that utilize the bearing geometry in such a manner as to both support load and provide an inherent and

  20. Geant4 simulations on medical Linac operation at 18 MV: Experimental validation based on activation foils

    NASA Astrophysics Data System (ADS)

    Vagena, E.; Stoulos, S.; Manolopoulou, M.

    2016-03-01

    The operation of a medical linear accelerator was simulated using the Geant4 code regarding to study the characteristics of an 18 MeV photon beam. Simulations showed that (a) the photon spectrum at the isocenter is not influenced by changes of the primary electron beam's energy distribution and spatial spread (b) 98% of the photon energy fluence scored at the isocenter is primary photons that have only interacted with the target (c) the number of contaminant electrons is not negligible since it fluctuated around 5×10-5 per primary electron or 2.40×10-3 per photon at the isocenter (d) the number of neutrons that are created by (γ, n) reactions is 3.13×10-6 per primary electron or 1.50×10-3 per photon at the isocenter (e) a flattening filter free beam needs less primary electrons in order to deliver the same photon fluence at the isocenter than a normal flattening filter operation (f) there is no significant increase of the surface dose due to the contaminant electrons by removing the flattening filter (g) comparing the neutron fluences per incident electron for the flattened and unflattened beam, the neutron fluencies is 7% higher for the unflattened beams. To validate the simulations results, the total neutron and photon fluence at the isocenter field were measured using nickel, indium, and natural uranium activation foils. The percentage difference between simulations and measurements was 1.26% in case of uranium and 2.45% in case of the indium foil regarding photon fluencies while for neutrons the discrepancy is higher up to 8.0%. The photon and neutron fluencies of the simulated experiments fall within a range of ±1 and ±2 sigma error, respectively, compared to the ones obtained experimentally.

  1. Absolute measurement of (198)Au activity in gold foil using plastic scintillators and a well-type NaI(Tl) detector.

    PubMed

    Kim, Yun Ho; Kim, Jungho; Lee, Jong-Man; Park, Hyeonseo

    2016-03-01

    A beta-gamma coincidence system has been developed for measuring (198)Au activity in gold foils. The system was validated by Monte Carlo simulations and by measuring the activity of a (60)Co point-source. To study effects such as self-shielding of beta particles in gold foils, (198)Au activity measurements and simulations were performed for various scintillators and foil sizes. The measured (198)Au activities were ~1% above the reference activity, which might be due to self-shielding of beta particles. The measured and simulated (198)Au activities agreed, suggesting feasibility of precise activity measurement.

  2. Active control of a cylinder wake flow by using a streamwise oscillating foil

    NASA Astrophysics Data System (ADS)

    Bao, Y.; Tao, J.

    2013-05-01

    In this study, numerical experiments are carried out to control the vortex shedding of a circular cylinder by utilizing an oscillating foil. The thin foil of elliptic shape undergoes prescribed harmonic oscillations in the streamwise direction in the near wake region. This simplified model is intended to study how wake dynamics are modified via localized wake disturbance, and then to stabilize the global wake instability. The results show that, at proper gap spacing, the oscillating foil can completely suppress the wake unsteadiness and recover the recirculating bubble type flow. The global instability suppression is then established on the imposition of local symmetry into the reversed flow behind the cylinder. It is revealed that the dynamic interaction between the main shears layer and oscillatory boundary layers is responsible for the wake stabilization mechanism. In addition, the kinematic/dynamic parameters related to foil motions and flow properties are widely discussed to reveal their effects on the performance of wake stabilization and drag reduction.

  3. Effects Due to the Structure and Materials of a Charge Stripping Foil on Activation of the RCS Injection Segment of J-PARC

    NASA Astrophysics Data System (ADS)

    Kato, Shuichi; Yamazaki, Yoshio; Yoshimoto, Masahiro; Kinsho, Michikazu; Sasao, Mamiko; Kenmotsu, Takahiro; Wada, Motoi

    Because of their robustness, Hybrid type thick Boron-doped Carbon (HBC) stripping foils are used in the 3 GeV Rapid Cycling Synchrotron (RCS) of Japan-Proton Accelerator Research Complex (J-PARC). The foil and the supporting structure are irradiated by H- beams. The activation of the surrounding structures and that of the foil itself is the problem to be solved. The ACAT (Atomic Collision in Amorphous Target) code has been modified to calculate the angle straggling of the transmission beam by multiple collisions in the foil. The results did not show any substantial deterioration of the beam optics due to the foil. The gamma spectra measured during a shutdown period of the RCS has been analyzed to see the correlation with the beam transport in the system.

  4. Au Foil Activation Measurement and Simulation of the Concrete Neutron Shielding Ability for the Proposed New SANRAD Facility

    NASA Astrophysics Data System (ADS)

    Radebe, M. J.; Korochinsky, S.; Strydom, W. J.; De Beer, F. C.

    The purpose of this study was to measure the effective neutron shielding characteristics of the new shielding material designed and manufactured to be used for the construction of the new SANRAD facility at Necsa, South Africa, through Au foil activation as well as MCNP simulations. The shielding capability of the high density shielding material was investigated in the worst case region (the neutron beam axis) of the experimental chamber for two operational modes. The everyday operational mode includes the 15 cm thick poly crystalline Bismuth filter at room temperature (assumed) to filter gamma-rays and some neutron spectrum energies. The second mode, dynamic imaging, will be conducted without the Bi-filter. The objective was achieved through a foil activation measurement at the current SANRAD facility and MCNP calculations. Several Au foilswere imbedded at different thicknesses(two at each position) of shielding material up to 80 cm thick to track the attenuation of the neutron beam over distance within the shielding material. The neutron flux and subsequently the associated dose rates were calculated from the activation levels of the Au foils. The concrete shielding material was found to provide adequate shielding for all energies of neutrons emerging from beam port no-2 of the SAFARI-1 research reactorwithin a thickness of 40 cm of concrete.

  5. Development of long-lived thick carbon stripper foils for high energy heavy ion accelerators by a heavy ion beam sputtering method

    SciTech Connect

    Muto, Hideshi; Ohshiro, Yukimitsu; Kawasaki, Katsunori; Oyaizu, Michihiro; Hattori, Toshiyuki

    2013-04-19

    In the past decade, we have developed extremely long-lived carbon stripper foils of 1-50 {mu}g/cm{sup 2} thickness prepared by a heavy ion beam sputtering method. These foils were mainly used for low energy heavy ion beams. Recently, high energy negative Hydrogen and heavy ion accelerators have started to use carbon stripper foils of over 100 {mu}g/cm{sup 2} in thickness. However, the heavy ion beam sputtering method was unsuccessful in production of foils thicker than about 50 {mu}g/cm{sup 2} because of the collapse of carbon particle build-up from substrates during the sputtering process. The reproduction probability of the foils was less than 25%, and most of them had surface defects. However, these defects were successfully eliminated by introducing higher beam energies of sputtering ions and a substrate heater during the sputtering process. In this report we describe a highly reproducible method for making thick carbon stripper foils by a heavy ion beam sputtering with a Krypton ion beam.

  6. FOIL ELEMENT FOR NUCLEAR REACTOR

    DOEpatents

    Noland, R.A.; Walker, D.E.; Spinrad, B.I.

    1963-07-16

    A method of making a foil-type fuel element is described. A foil of fuel metal is perforated in; regular design and sheets of cladding metal are placed on both sides. The cladding metal sheets are then spot-welded to each other through the perforations, and the edges sealed. (AEC)

  7. Foil bearings

    NASA Technical Reports Server (NTRS)

    Elrod, David A.

    1993-01-01

    The rolling element bearings (REB's) which support many turbomachinery rotors offer high load capacity, low power requirements, and durability. Two disadvantages of REB's are: (1) rolling or sliding contact within the bearing has life-limiting consequences; and (2) REB's provide essentially no damping. The REB's in the Space Shuttle Main Engine (SSME) turbopumps must sustain high static and dynamic loads, at high speeds, with a cryogenic fluid as lubricant and coolant. The pump end ball bearings limit the life of the SSME high pressure oxygen turbopump (HPOTP). Compliant foil bearing (CFB) manufacturers have proposed replacing turbopump REB's with CFB's CFB's work well in aircraft air cycle machines, auxiliary power units, and refrigeration compressors. In a CFB, the rotor only contracts the foil support structure during start up and shut down. CFB damping is higher than REB damping. However, the load capacity of the CFB is low, compared to a REB. Furthermore, little stiffness and damping data exists for the CFB. A rotordynamic analysis for turbomachinery critical speeds and stability requires the input of bearing stiffness and damping coefficients. The two basic types of CFB are the tension-dominated bearing and the bending-dominated bearing. Many investigators have analyzed and measured characteristics of tension-dominated foil bearings, which are applied principally in magnetic tape recording. The bending-dominated CFB is used more in rotating machinery. This report describes the first phase of a structural analysis of a bending-dominated, multileaf CFB. A brief discussion of CFB literature is followed by a description and results of the present analysis.

  8. Foil bearings

    NASA Astrophysics Data System (ADS)

    Elrod, David A.

    1993-11-01

    The rolling element bearings (REB's) which support many turbomachinery rotors offer high load capacity, low power requirements, and durability. Two disadvantages of REB's are: (1) rolling or sliding contact within the bearing has life-limiting consequences; and (2) REB's provide essentially no damping. The REB's in the Space Shuttle Main Engine (SSME) turbopumps must sustain high static and dynamic loads, at high speeds, with a cryogenic fluid as lubricant and coolant. The pump end ball bearings limit the life of the SSME high pressure oxygen turbopump (HPOTP). Compliant foil bearing (CFB) manufacturers have proposed replacing turbopump REB's with CFB's CFB's work well in aircraft air cycle machines, auxiliary power units, and refrigeration compressors. In a CFB, the rotor only contracts the foil support structure during start up and shut down. CFB damping is higher than REB damping. However, the load capacity of the CFB is low, compared to a REB. Furthermore, little stiffness and damping data exists for the CFB. A rotordynamic analysis for turbomachinery critical speeds and stability requires the input of bearing stiffness and damping coefficients. The two basic types of CFB are the tension-dominated bearing and the bending-dominated bearing. Many investigators have analyzed and measured characteristics of tension-dominated foil bearings, which are applied principally in magnetic tape recording. The bending-dominated CFB is used more in rotating machinery. This report describes the first phase of a structural analysis of a bending-dominated, multileaf CFB. A brief discussion of CFB literature is followed by a description and results of the present analysis.

  9. Monolithic exploding foil initiator

    SciTech Connect

    Welle, Eric J; Vianco, Paul T; Headley, Paul S; Jarrell, Jason A; Garrity, J. Emmett; Shelton, Keegan P; Marley, Stephen K

    2012-10-23

    A monolithic exploding foil initiator (EFI) or slapper detonator and the method for making the monolithic EFI wherein the exploding bridge and the dielectric from which the flyer will be generated are integrated directly onto the header. In some embodiments, the barrel is directly integrated directly onto the header.

  10. Passive Thermal Management of Foil Bearings

    NASA Technical Reports Server (NTRS)

    Bruckner, Robert J. (Inventor)

    2015-01-01

    Systems and methods for passive thermal management of foil bearing systems are disclosed herein. The flow of the hydrodynamic film across the surface of bearing compliant foils may be disrupted to provide passive cooling and to improve the performance and reliability of the foil bearing system.

  11. Foil Electron Multiplier

    DOEpatents

    Funsten, Herbert O.; Baldonado, Juan R.; Dors, Eric E.; Harper, Ronnie W.; Skoug, Ruth M.

    2006-03-28

    An apparatus for electron multiplication by transmission that is designed with at least one foil having a front side for receiving incident particles and a back side for transmitting secondary electrons that are produced from the incident particles transiting through the foil. The foil thickness enables the incident particles to travel through the foil and continue on to an anode or to a next foil in series with the first foil. The foil, or foils, and anode are contained within a supporting structure that is attached within an evacuated enclosure. An electrical power supply is connected to the foil, or foils, and the anode to provide an electrical field gradient effective to accelerate negatively charged incident particles and the generated secondary electrons through the foil, or foils, to the anode for collection.

  12. Boron foils for RDDS experiment

    NASA Astrophysics Data System (ADS)

    Lipski, A. R.; Rainovski, G.; Pietralla, N.; Dewald, A.

    2008-06-01

    Application of the deposition method based on the vibrational motion of micro particles in an electrostatic field [I. Sugai, Nucl. Instr. and Meth. A 397 (1997) 81] is described for the production of isotopic 11B foils. The method proved suitable for target production of this typically brittle material when a very flat target surface was required. The goal to produce 11B targets of 160-350 μg/cm 2 was achieved by depositing the boron on a thin foil substrate, such as Nb and Sn. The coated foil was stretched flat before it was mounted on a frame.

  13. Heat Transfer Measurements with Surface Mounted Foil-Sensors in an Active Mode: A Comprehensive Review and a New Design

    PubMed Central

    Mocikat, Horst; Herwig, Heinz

    2009-01-01

    A comprehensive review of film-sensors shows that they are primarily operated in a passive mode, i.e. without being actively heated to an extent, whereby they create a heat transfer situation on their own. Only when these sensors are used for wall shear stress measurements, the detection of laminar/turbulent transition, or the measurement of certain flow velocities, they are operated in an active mode, i.e. heated by an electrical current (after an appropriate calibration). In our study we demonstrate how these R(T)-based sensors (temperature dependence of the electrical resistance R) can also be applied in an active mode for heat transfer measurements. These measurements can be made on cold, unheated bodies, provided certain requirements with respect to the flow field are fulfilled. Our new sensors are laminated nickel- and polyimide-foils manufactured with a special technology, which is also described in detail. PMID:22574060

  14. Foil changing apparatus

    DOEpatents

    Crist, Charles E.; Ives, Harry C.; Leifeste, Gordon T.; Miller, Robert B.

    1988-01-01

    A self-contained hermetically sealed foil changer for advancing a portion of foil web into a position normal to the path of a high energy particle beam. The path of the beam is defined generally by an aperture plate and cooperating axially movable barrel such that the barrel can be advanced toward the plate thereby positioning a portion of the foil across the beam path and sealing the foil between the barrel and the plate to form a membrane across said beam path. A spooling apparatus contained in the foil changer permits selectively advancing a fresh supply of foil across the beam path without breaking the foil changer seal.

  15. A vortex-lattice method in the linear theory on a two-dimensional supercavitating flat plate foil

    NASA Astrophysics Data System (ADS)

    Kida, T.; Take, T.

    1983-02-01

    The vortex-lattice method has been found very satisfactory in the case of steady subsonic wing theory, however, the discrete numerical methods, such as the vortex-lattice method, have not been studied in detail for supercavitating flows. One of the discrete numerical method, a vortex-lattice method, is developed in the present paper for cavitating flows around a two dimensional flat plate foil. The governing equations in the linear theory are represented as a set of coupled integral equations with Cauchy kernel, and there are unknown functions which are not under integral signs. For solving them, they are exchanged to an alternative set of coupled integral equations by a new variable, and the present vortex-lattice method is schemed for equal spacing of the vortices and sources in this new variable. The position of the collocation points is determined, and it is sufficient to treat unknown functions which are not integral signs as step functions. Moreover, the proof of the convergence of this method is shown and the accuracy is estimated.

  16. Multilayer reactive foils: Fabrication, reaction characterization, and room-temperature joining

    NASA Astrophysics Data System (ADS)

    Reiss, Michael Eric

    The self-propagating reactive multilayer foils studied here were composed of alternating nanoscale layers of Al and Ni. The reactions associated with these foils can reach temperatures well over 1600°C with propagation velocities one the order of 1 to 10 m/s. In order to characterized these reactions, a high spatial resolution (50 micron), high temporal resolution (25 microsecond) and high temperature resolution ratio pyrometer with a range of 900°C to 2000°C, was designed and assembled. The pyrometer was optimized for use with the self-propagating reactive foil systems and was used in conjunction with an apparatus for measuring the propagation velocity of these reactive foils. The custom velocity and temperature devices were used to analyze the interrelationships between reaction velocity, maximum temperature, and activation energy in the Al-Ni reactive foil system. The results of this study indicate that final temperature and layer thickness may have opposing influences on reaction rate. The process of joining SiC to Ti-6-4 was investigated from the standpoint of using reactive foils as an in-situ heat source. Advances in reactive foil deposition techniques were made to facilitate the fabrication of thick foils (>100 micron). Room temperature reactive foil joining with no external heat source was demonstrated and preliminary studies on the substantial bond strength were performed. Finally, an investigation into the feasibility of fabricating reactive foils from layers of metal sheet was performed. The combined techniques of swaging and rolling were shown to be a promising method for the scale-up of reactive foil production, and reactive foils with properties similar to those of vapor deposited materials were be obtained via this process.

  17. Synthesis of CuO nanowires on Cu-foil using thermal oxidation method, a novel annealing process

    NASA Astrophysics Data System (ADS)

    Eshghi, Hosein; Goodarzi, Mehdi Torabi

    2016-02-01

    Cupric oxide (CuO) nanowires (NWs) on Cu-foils were prepared by thermal oxidation method in air atmosphere using two annealing manners (continuous and steps) in the temperature ranges of 400-500∘C and 400-600∘C. Morphology and microstructure of the NWs was studied using field effect scanning electron microscopy (FESEM), X-ray diffractogram (XRD), transmission electron microscopy (TEM) and selected area electron diffraction (SAED). Optical reflectance spectrum was used for the optical investigation of the layers. We found the NWs formed have two different morphologies, curved and straight, with diameters between 50 nm and 200 nm and lengths between 5 μm and 10 μm. SAED pattern of a single NW revealed as a CuO single crystal with monoclinic structure. The reflectance spectra analysis based on Kubelka-Munk method showed that the band gap energy of the CuO NWs are varying in the range of 1.40-1.47 eV depending on the crystallite sizes of the NWs, a confirmation for the happening of the quantum confined effect in these samples.

  18. Efficiency and lifetime of carbon foils

    SciTech Connect

    Chou, W.; Kostin, M.; Tang, Z.; /Fermilab

    2006-11-01

    Charge-exchange injection by means of carbon foils is a widely used method in accelerators. This paper discusses two critical issues concerning the use of carbon foils: efficiency and lifetime. An energy scaling of stripping efficiency was suggested and compared with measurements. Several factors that determine the foil lifetime--energy deposition, heating, stress and buckling--were studied by using the simulation codes MARS and ANSYS.

  19. A simple and inclusive method to determine the habit plane in transmission electron microscope based on accurate measurement of foil thickness

    SciTech Connect

    Qiu, Dong Zhang, Mingxing

    2014-08-15

    A simple and inclusive method is proposed for accurate determination of the habit plane between bicrystals in transmission electron microscope. Whilst this method can be regarded as a variant of surface trace analysis, the major innovation lies in the improved accuracy and efficiency of foil thickness measurement, which involves a simple tilt of the thin foil about a permanent tilting axis of the specimen holder, rather than cumbersome tilt about the surface trace of the habit plane. Experimental study has been done to validate this proposed method in determining the habit plane between lamellar α{sub 2} plates and γ matrix in a Ti–Al–Nb alloy. Both high accuracy (± 1°) and high precision (± 1°) have been achieved by using the new method. The source of the experimental errors as well as the applicability of this method is discussed. Some tips to minimise the experimental errors are also suggested. - Highlights: • An improved algorithm is formulated to measure the foil thickness. • Habit plane can be determined with a single tilt holder based on the new algorithm. • Better accuracy and precision within ± 1° are achievable using the proposed method. • The data for multi-facet determination can be collected simultaneously.

  20. Calculation of Dynamic Coefficients for Multiwound Foil Bearings

    NASA Astrophysics Data System (ADS)

    Feng, Kai; Kaneko, Shigehiko

    Dynamic performance of multiwound foil bearings with the effects of foil local deflection is investigated. The foils, separated and supported by projections on the ir surface are treated as thin plates. Deflections of the foils are solved with a finite element model. The air pressure is calculated with the Reynolds' equation by treating the lubricant as an isothermal idea gas. The effects of foils are simulated with the deflection of top foil added to the film thickness. A finite difference computer program is developed to solve the Reynolds equation and the elastic deflection equation, simultaneously. Perturbation method is used to determine the dynamic coefficients. The effects of foil deflection is discussed by comparing the dynamic coefficients of a foil bearing and a rigid bearing. Experimental data from a test rig supported by two multiwound foil bearings are used to validate this numerical solution.

  1. Free Surface and Flapping Foil Interactions

    NASA Astrophysics Data System (ADS)

    Ananthakrishnan, Palaniswamy

    2014-11-01

    Flapping foils for station-keeping of a near-surface body in a current is analyzed using a finite-difference method based on boundary-fitted coordinates. The foils are hinge-connected to the aft of the body and subject to pitch oscillation. Results are obtained for a range of Strouhal number, Froude number, unsteady frequency parameter τ, Reynolds number and the depth of foil submergence. Results show that at low Strouhal number (St < 0 . 1) and sub-critical unsteady parameter τ < 0 . 25 , the flapping generates drag instead of thrust. At high Strouhal number and super-critical value of the unsteady parameter (τ > 0 . 25) flapping generates high thrust with low efficiency. Thrust and efficiency are found to decrease with decreasing submergence depth of the foil. At the critical τ = 0 . 25 and shallow submergence of the foil, the standing wave generated above the foil continues to grow until breaking; both the thrust and efficiency of the foil are reduced at the critical τ. The necessary conditions for optimal thrust generation by a flapping foil underneath the free surface are found to be (i) Strouhal number in the range from 0.25 to 0.35, (ii) unsteady parameter τ > 0 . 25 and (iii) the maximum angle of attack less than 15° for the flat-plate foil. Supported by the US Office of Naval Research through the Naval Engineering Education Center (NEEC) Consortium of the University of Michigan, Ann Arbor.

  2. Hermes III endpoint energy calculation from photonuclear activation of 197Au and 58Ni foils

    SciTech Connect

    Parzyck, Christopher Thomas

    2014-09-01

    A new process has been developed to characterize the endpoint energy of HERMES III on a shot-to-shot basis using standard dosimetry tools from the Sandia Radiation Measurements Laboratory. Photonuclear activation readings from nickel and gold foils are used in conjunction with calcium fluoride thermoluminescent dosimeters to derive estimated electron endpoint energies for a series of HERMES shots. The results are reasonably consistent with the expected endpoint voltages on those shots.

  3. Do Learning Activities Improve Students' Ability to Construct Explanatory Models with a Prism Foil Problem?

    ERIC Educational Resources Information Center

    Gojkošek, Mihael; Sliško, Josip; Planinšic, Gorazd

    2013-01-01

    The transfer of knowledge is considered to be a fundamental goal of education; therefore, knowing and understanding the conditions that influence the efficiency of the transfer from learning activity to problem solving play a decisive role in the improvement of science education. In this article, the results of a study of 196 high school students'…

  4. Analysis of improved neutron activation technique using thick foils for application on medical LINAC environment

    NASA Astrophysics Data System (ADS)

    Vagena, E.; Stoulos, S.; Manolopoulou, M.

    2016-01-01

    An improved neutron activation technique is analyzed that can be used for the characterization of the neutron field in low neutron flux environments, such as medical Linacs. Due to the much lower neutron fluence rates, thick materials instead of thin have been used. The study is focused on the calculations of basic components of the neutron activation analysis that are required for accurate results, such as the efficiency of the gamma detector used for γ-spectrometry as well as crucial correction factors that are required when dealing with thick samples in different geometries and forms. A Monte Carlo detector model, implemented by Geant4 MC Code was adjusted in accordance to results from various measurements performed. Moreover, regarding to estimate the self-shielding correction factors a new approach using both Monte Carlo and analytical approach was presented. This improvement gives more accurate results, which are important for both activation and shielding studies that take place in many facilities. A quite good agreement between the neutron fluxes is achieved; according to the data obtained a mean value of (2.13±0.34)×105 ncm-2 s-1 is representative for the isocenter of the specific Linac that corresponds to fluence of (5.53±0.94)×106 ncm-2 Gy-1. Comparable fluencies reported in the literature for similar Linacs operating with photon beams at 15 MeV.

  5. Measuring neutron yield and ρR anisotropies with activation foils at the National Ignition Facility

    NASA Astrophysics Data System (ADS)

    Bleuel, D. L.; Bernstein, L. A.; Bionta, R. M.; Cooper, G. W.; Drury, O. B.; Hagmann, C. A.; Knittel, K. M.; Leeper, R. J.; Ruiz, C. L.; Schneider, D. H. G.; Yeamans, C. B.

    2013-11-01

    Neutron yields at the National Ignition Facility (NIF) are measured with a suite of diagnostics, including activation of ˜20-200 g samples of materials undergoing a variety of energy-dependent neutron reactions. Indium samples were mounted on the end of a Diagnostic Instrument Manipulator (DIM), 25-50 cm from the implosion, to measure 2.45 MeV D-D fusion neutron yield. The 336.2 keV gamma rays from the 4.5 hour isomer of 115mIn produced by (n,n') reactions are counted in high-purity germanium detectors. For capsules producing D-T fusion reactions, zirconium and copper are activated via (n,2n) reactions at various locations around the target chamber and bay, measuring the 14 MeV neutron yield to accuracies on order of 7%. By mounting zirconium samples on ports at nine locations around the NIF chamber, anisotropies in the primary neutron emission due to fuel areal density asymmetries can be measured to a relative precision of 3%.

  6. Resistive Switching Memory of TiO2 Nanowire Networks Grown on Ti Foil by a Single Hydrothermal Method

    NASA Astrophysics Data System (ADS)

    Xiao, Ming; Musselman, Kevin P.; Duley, Walter W.; Zhou, Norman Y.

    2017-04-01

    The resistive switching characteristics of TiO2 nanowire networks directly grown on Ti foil by a single-step hydrothermal technique are discussed in this paper. The Ti foil serves as the supply of Ti atoms for growth of the TiO2 nanowires, making the preparation straightforward. It also acts as a bottom electrode for the device. A top Al electrode was fabricated by e-beam evaporation process. The Al/TiO2 nanowire networks/Ti device fabricated in this way displayed a highly repeatable and electroforming-free bipolar resistive behavior with retention for more than 104 s and an OFF/ON ratio of approximately 70. The switching mechanism of this Al/TiO2 nanowire networks/Ti device is suggested to arise from the migration of oxygen vacancies under applied electric field. This provides a facile way to obtain metal oxide nanowire-based ReRAM device in the future.

  7. Impact Ignition of Low Density Mechanically Activated and Multilayer Foil Ni/Al

    NASA Astrophysics Data System (ADS)

    Beason, Matthew; Mason, B.; Son, Steven; Groven, Lori

    2013-06-01

    Mechanical activation (MA) via milling of reactive materials provides a means of lowering the ignition threshold of shock initiated reactions. This treatment provides a finely mixed microstructure with wide variation in the resulting scales of the intraparticle microstructure that makes model validation difficult. In this work we consider nanofoils produced through vapor deposition with well defined periodicity and a similar degree of fine scale mixing. This allows experiments that may be easier to compare with computational models. To achieve this, both equimolar Ni/Al powder that has undergone MA using high energy ball milling and nanofoils milled into a powder using low energy ball milling were used. The Asay Shear impact experiment was conducted on both MA Ni/Al and Ni/Al nanofoil-based powders at low densities (<60%) to examine their impact response and reaction behavior. Scanning electron microscopy and energy-dispersive x-ray spectroscopy were used to verify the microstructure of the materials. The materials' mechanical properties were evaluated using nano-indentation. Onset temperatures were evaluated using differential thermal analysis/differential scanning calorimetry. Impact ignition thresholds, burning rates, temperature field, and ignition delays are reported. Funding from the Defense Threat Reduction Agency (DTRA) Grant Number HDTRA1-10-1-0119. Counter-WMD basic research program, Dr. Suhithi M. Peiris, program director is gratefully acknowledged.

  8. Cryogenic foil bearing turbopumps

    NASA Technical Reports Server (NTRS)

    Gu, Alston L.

    1993-01-01

    Cryogenic foil bearing turbopumps offer high reliability and low cost. The fundamental cryogenic foil bearing technology has been validated in both liquid hydrogen and liquid oxygen. High load capacity, excellent rotor dynamics, and negligible bearing wear after over 100 starts and stops, and over many hours of testing, were observed in both fluids. An experimental liquid hydrogen foil bearing turbopump was also successfully demonstrated. The results indicate excellent stability, high reliability, wide throttle-ability, low bearing cooling flow, and two-phase bearing operability. A liquid oxygen foil bearing turbopump has been built and is being tested at NASA MSFC.

  9. Foil Face Seal Testing

    NASA Technical Reports Server (NTRS)

    Munson, John

    2009-01-01

    In the seal literature you can find many attempts by various researchers to adapt film riding seals to the gas turbine engine. None have been successful, potential distortion of the sealing faces is the primary reason. There is a film riding device that does accommodate distortion and is in service in aircraft applications, namely the foil bearing. More specifically a foil thrust bearing. These are not intended to be seals, and they do not accommodate large axial movement between shaft & static structure. By combining the 2 a unique type of face seal has been created. It functions like a normal face seal. The foil thrust bearing replaces the normal primary sealing surface. The compliance of the foil bearing allows the foils to track distortion of the mating seal ring. The foil seal has several perceived advantages over existing hydrodynamic designs, enumerated in the chart. Materials and design methodology needed for this application already exist. Also the load capacity requirements for the foil bearing are low since it only needs to support itself and overcome friction forces at the antirotation keys.

  10. Surface treatment using metal foil liner

    NASA Technical Reports Server (NTRS)

    Garvey, Ray

    1989-01-01

    A metal foil liner can be used to seal large area surfaces. Characteristics of the two-layer foil liner are discussed. Micrographs for foil-to-foil, foil-to-composite, visible seams, and hidden seams are examined.

  11. Beam-foil spectroscopy

    SciTech Connect

    Berry, H.G.; Hass, M.

    1982-01-01

    A brief survey of some applications of beam-foil spectroscopy is presented. Among the topics covered are lifetime and magnetic moment measurements, nuclear alignment, and polarized light production. (AIP)

  12. SNS Injection Foil Experience

    SciTech Connect

    Cousineau, Sarah M; Galambos, John D; Kim, Sang-Ho; Ladd, Peter; Luck, Chris; Peters, Charles C; Polsky, Yarom; Shaw, Robert W; Macek, Robert James; Raparia, Deepak; Plum, Michael A

    2010-01-01

    The Spallation Neutron Source comprises a 1 GeV, 1.4 MW linear accelerator followed by an accumulator ring and a liquid mercury target. To manage the beam loss caused by the H0 excited states created during the H charge exchange injection into the accumulator ring, the stripper foil is located inside one of the chicane dipoles. This has some interesting consequences that were not fully appreciated until the beam power reached about 840 kW. One consequence was sudden failure of the stripper foil system due to convoy electrons stripped from the incoming H beam, which circled around to strike the foil bracket and cause bracket failure. Another consequence is that convoy electrons can reflect back up from the electron catcher and strike the foil and bracket. An additional contributor to foil system failure is vacuum breakdown due to the charge developed on the foil by secondary electron emission. In this paper we will detail these and other interesting failure mechanisms, and describe the improvements we have made to mitigate them.

  13. Improvements in Fabrication of Elastic Scattering Foils Used to Measure Neutron Yield by the Magnetic Recoil Spectrometer

    DOE PAGES

    Reynolds, H. G.; Schoff, M. E.; Farrell, M. P.; ...

    2016-08-01

    The magnetic recoil spectrometer uses a deuterated polyethylene polymer (CD2) foil to measure neutron yield in inertial confinement fusion experiments. Higher neutron yields in recent experiments have resulted in primary signal saturation in the detector CR-39 foils, necessitating the fabrication of thinner CD2 foils than established methods could provide. A novel method of fabricating deuterated polymer foils is described. The resulting foils are thinner, smoother, and more uniform in thickness than the foils produced by previous methods. Here, these new foils have successfully been deployed at the National Ignition Facility, enabling higher neutron yield measurements than previous foils, with nomore » primary signal saturation.« less

  14. Improvements in Fabrication of Elastic Scattering Foils Used to Measure Neutron Yield by the Magnetic Recoil Spectrometer

    SciTech Connect

    Reynolds, H. G.; Schoff, M. E.; Farrell, M. P.; Gatu Johnson, M.; Bionta, R. M.; Frenje, J. A.

    2016-08-01

    The magnetic recoil spectrometer uses a deuterated polyethylene polymer (CD2) foil to measure neutron yield in inertial confinement fusion experiments. Higher neutron yields in recent experiments have resulted in primary signal saturation in the detector CR-39 foils, necessitating the fabrication of thinner CD2 foils than established methods could provide. A novel method of fabricating deuterated polymer foils is described. The resulting foils are thinner, smoother, and more uniform in thickness than the foils produced by previous methods. Here, these new foils have successfully been deployed at the National Ignition Facility, enabling higher neutron yield measurements than previous foils, with no primary signal saturation.

  15. In situ synthesis of TiH{sub 2} layer on metallic titanium foil through gaseous hydrogen free acid-hydrothermal method

    SciTech Connect

    Ren, Na; Wang, Guancong; Liu, Hong; Ohachi, Tadashi

    2014-02-01

    Graphical abstract: The reaction mechanism for in situ synthesizing TiH{sub 2} layer on titanium foil by a gaseous hydrogen free acid-hydrothermal methodology. - Highlights: • A dense TiH{sub 2} layer is synthesized by a hydrogen free acid-hydrothermal method. • Hydrogen in a TiH{sub 2} layer synthesized can release at low temperature. • During the dehydrogenation process, there is no any intermediate phase forming. • We report a method of low-cost, low-risk and convenience toward productive TiH{sub 2}. - Abstract: A novel strategy for synthesis of TiH{sub 2} layer on surface of metallic titanium by using an acid-hydrothermal method was proposed. During the synthesis process, no any elemental hydrogen was involved. X-ray powder diffraction, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy and scanning electron microscopy results confirmed that a TiH{sub 2} layer of 20 μm thickness on a Ti foil surface can be formed in situ by an interface reaction of metallic titanium with sulfuric acid solution, hydrochloric acid, or phosphoric acid, which is a hydrogen self-storage process. By tuning reaction parameters, for example, concentration of acid, composition and morphology of TiH{sub 2}-Ti hybrid materials can be adjusted. The TiH{sub 2} layer on a metallic titanium surface can be decompounded completely heated below 400 °C. This convenient, safe and low-cost method is a promising gaseous hydrogen free approach for the synthesis of hydride-based hydrogen storage materials.

  16. Carbon stripper foils used in the Los Alamos PSR

    SciTech Connect

    Borden, M.J.; Plum, M.A.; Sugai, I.

    1997-12-01

    Carbon stripper foils produced by the modified controlled ACDC arc discharge method (mCADAD) at the Institute for Nuclear Study have been tested and used for high current 800-MeV beam production in the Proton Storage Ring (PSR) since 1993. Two foils approximately 110 {mu}g/cm{sup 2} each are sandwiched together to produce an equivalent 220 {mu}g/cm{sup 2} foil. The foil sandwitch is supported by 4-5 {mu}m diameter carbon filters attached to an aluminum frame. These foils have survived as long as five months during PSR normal beam production of near 70 {mu}A average current on target. Typical life-times of other foils vary from seven to fourteen days with lower on-target average current. Beam loss data also indicate that these foils have slower shrinkage rates than standard foils. Equipment has been assembled and used to produce foils by the mCADAD method at Los Alamos. These foils will be tested during 1997 operation.

  17. SU-E-T-151: Enhanced Radiation Attenuation with Multi-Layer Foils

    SciTech Connect

    Warmington, L; Watanabe, Y

    2014-06-01

    Purpose: To evaluate the effect of increasing the number of thin high Z foils on the dose enhancement and the overall radiation attenuation with a 24MV photon beam. Methods: DOSXYZnrc was used to perform Monte Carlo simulations of multi-layer lead foil configurations. The foil size was 7cm x 7cm. and the foil thickness was adjusted to give a combined thickness of 1mm. The number of foils used was 4, 6, 8, and 10. The separation between foils was also varied from 3 to 9 mm. The Mohan 24MV energy spectrum was used as a photon source. The field size was 5cm x 5cm and SSD was 100 cm. The phantom size was 16cm × 16cm × 28cm. The number of histories ranged from 1 to 2 billion. The percentage difference of the dose between the medium with foils and the homogeneous water was computed along the beam axis. The minimum dose enhancement and the change of integrated dose between the foils were determined. Results: Increasing the number of foils resulted in a decrease in the minimum dose enhancement. The highest dose region occurred in the last section for the 4 and 6 foil cases, whereas the 8 and 10 foil configurations showed the maximum dose region towards the center of the foil group. Increasing the number of foils increased the total integrated dose between foils. For example, the total integrated dose increase between the first and the last foils with a 3mm foil separation were 34.2, 43.4, 57.4, and 64.7% for 4, 6, 8 and 10 foils, respectively. Conclusion: This work showed the degree of dose enhancement around multiple thin lead foils. The results suggest that the total attenuation of photon beam can be increased by increasing the number of foils with a fixed total foil thickness.

  18. Producing titanium aluminide foil from plasma-sprayed preforms

    SciTech Connect

    Jha, S.C.; Forster, J.A. )

    1993-07-01

    A new method was used to fabricate foils of Ti-6Al-4V (Ti-6-4) alloy and Ti-14Al-21Nb(Ti-14-21) titanium aluminide, starting from a plasma-sprayed (PS) preform. The foils were 100 percent dense, with microstructures similar to those of wrought (IM) foil material. The foil made from PS preforms were characterized by the mechanical properties equivalent to their IM-processed counterparts. It is concluded that the method of roll consolidation of a PS preform is well suited for alloys and intermetallics that do not possess extensive hot and cold workability. 6 refs.

  19. Effects of Aluminum Foil Packaging on Elemental Analysis of Bone.

    PubMed

    Lewis, Lyniece; Christensen, Angi M

    2016-03-01

    Burned skeletal material is often very fragile and at high risk for fragmentation during packaging and transportation. One method that has been suggested to protect bones in these cases is to carefully wrap them in aluminum foil. Traces of aluminum, however, are known to transfer from foil packaging materials to food products. If such transfer occurs between aluminum foil and bones, it could interfere with subsequent chemical, elemental and isotopic analyses, which are becoming more common in forensic anthropological investigations. This study examined aluminum levels in bones prior to and following the use of aluminum foil packaging and storage for a 6-week period. Results indicate no significant change in the detected levels of aluminum (p > 0.05), even when packaged in compromised foil and exposed to elevated temperatures. Aluminum foil can therefore continue to be recommended as a packaging medium without affecting subsequent chemical examinations.

  20. Actinide Foil Production for MPACT Research

    SciTech Connect

    Beller, Denis

    2012-10-30

    or UO2 in extremely thin layers (1 to 2 mg/cm2) on various media such as films, foils, or discs. After many months of investigation and trials in FY10 and 11, UNLV researchers developed a new method to produce pure UO2 deposits on foils using a unique approach, which has never been demonstrated, that involves dissolution of U3O8 directly into room temperature ionic liquid (RTIL) followed by electrodeposition from the RTIL-uDU solution (Th deposition from RTIL had been previously demonstrated). The high-purity dissolution of the U3O8 permits the use of RTIL solutions for deposition of U on metal foils in layers without introducing contamination. In FY10 and early FY11 a natural U surrogate for the uDU was used to investigate this and other techniques. In this research project UNLV will deposit directly from RTIL to produce uDU and Th foils devoid of possible contaminants. After these layers have been deposited, they will be examined for purity and uniformity. UNLV will complete the development and demonstration of the RTIL technology/ methodology to prepare uDU and Th samples for use in constructing fast-neutron detectors. Although this material was purchased for use in research using fast-fission chamber detectors for active inspection techniques for MPACT, it could also contribute to R&D for other applications, such as cross section measurements or neutron spectroscopy for national security

  1. Process for anodizing aluminum foil

    SciTech Connect

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

    1984-11-06

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

  2. Foil fabrication for the ROMANO event. Revision 1

    SciTech Connect

    Romo, J.G. Jr.; Weed, J.W.; Griggs, G.E.; Brown, T.G.; Tassano, P.L.

    1984-06-13

    The Vacuum Processes Lab (VPL), of LLNL's M.E. Dept. - Material Fabrication Division (MFD), conducted various vacuum related support activities for the ROMANO nuclear physics experiment. This report focuses on the foil fabrication activities carried out between July and November 1983 for the ROMANO event. Other vacuum related activities for ROMANO, such as outgassing tests of materials, are covered in separate documentation. VPL was asked to provide 270 coated Parylene foils for the ROMANO event. However, due to the developmental nature of some of the procedures, approximately 400 coated foils were processed. In addition, VPL interacted with MFD's Plastics Shop to help supply Parylene substrates to other organizations (i.e., LBL and commercial vendors) which had also been asked to provide coated foils for ROMANO. The purposes of this report are (A) to document the processes developed and the techniques used to produce the foils, and (B) to suggest future directions. The report is divided into four sections describing: (1) nuclear target foil fabrication, (2) Parylene substrate preparation and production, (3) calibration foil fabrication, and (4) foil and substrate inspections.

  3. Direct synthesis of Cu{sub 2}O-RGO nanocomposite on Cu foil by thermal evaporation method and its field emission study

    SciTech Connect

    Bansode, Sanjeewani; Khare, Ruchita; Harpale, Kashmira; Kolhe, Pankaj; More, Mahendra

    2015-06-24

    In this work, a facile one step thermal evaporation method for deposition of Cu{sub 2}O nanoparticles on RGO sheets to form Cu{sub 2}O-RGO nanocomposite is discussed. To the best of our knowledge, this is the first report on Cu{sub 2}O-RGO nanocomposite, directly grown on Cu foil by a simple thermal evaporation route. The as –prepared nanocomposite exhibits well dispersed Cu{sub 2}O nanoparticles distributed all over the graphene sheet. Field emission properties of the nanocomposite were investigated at a base pressure of 1*10{sup −8} torr. The turn on field, required to draw emission current density of 0.1µA/cm2, was found to be 3.8V/µm with a maximum emission current density of 80 µA/cm2 at an applied field of 6.8 V/µm. Moreover, the nanocomposite shows fairly good emission stability without significant degradation of emission current. The FE results seem to be encouraging, indicative of potential candidature of the Cu{sub 2}O-RGO nanocomposite emitter as an electron source for practical applications in vacuum nanoelectronic devices.

  4. Safe and consistent method of spot-welding platinum thermocouple wires and foils for high temperature measurements

    NASA Astrophysics Data System (ADS)

    Orr, G.; Roth, M.

    2012-08-01

    A low-voltage (mV) electronically triggered spot welding system for fabricating fine thermocouples and thin sheets used in high-temperature characterization of materials' properties is suggested. The system is based on the capacitance discharge method with a timed trigger for obtaining reliable and consistent welds. In contrast to existing techniques based on employing high voltage DC supplies for charging the capacitor or supplies with positive and negative rails, this method uses a simple, standard dual power supply available at most of the physical laboratories or can be acquired at a low cost. In addition, an efficient and simple method of fabricating non-sticking electrodes that do not contaminate the weld area is suggested and implemented.

  5. 75 FR 1596 - Grant of Authority for Subzone Status, Reynolds Packaging LLC (Aluminum Foil Liner Stock...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-12

    ... (Aluminum Foil Liner Stock), Louisville, Kentucky Pursuant to its authority under the Foreign-Trade Zones... to the Board for authority to establish a special-purpose subzone at the aluminum foil liner stock... status for activity related to the manufacturing and distribution of aluminum foil liner stock...

  6. Compliant Foil Seal Investigations

    NASA Technical Reports Server (NTRS)

    Proctor, Margaret; Delgado, Irebert

    2004-01-01

    Room temperature testing of an 8.5 inch diameter foil seal was conducted in the High Speed, High Temperature Turbine Seal Test Rig at the NASA Glenn Research Center. The seal was operated at speeds up to 30,000 rpm and pressure differentials up to 75 psid. Seal leakage and power loss data will be presented and compared to brush seal performance. The failure of the seal and rotor coating at 30,000 rpm and 15 psid will be presented and future development needs discussed.

  7. Thermal Sensitive Foils in Physics Experiments

    ERIC Educational Resources Information Center

    Bochnícek, Zdenek; Konecný, Pavel

    2014-01-01

    The paper describes a set of physics demonstration experiments where thermal sensitive foils are used for the detection of the two dimensional distribution of temperature. The method is used for the demonstration of thermal conductivity, temperature change in adiabatic processes, distribution of electromagnetic radiation in a microwave oven and…

  8. Thermal sensitive foils in physics experiments

    NASA Astrophysics Data System (ADS)

    Bochníček, Zdeněk; Konečný, Pavel

    2014-07-01

    The paper describes a set of physics demonstration experiments where thermal sensitive foils are used for the detection of the two dimensional distribution of temperature. The method is used for the demonstration of thermal conductivity, temperature change in adiabatic processes, distribution of electromagnetic radiation in a microwave oven and detection of resonant acoustic oscillations in a Rubens’ tube.

  9. Design, Fabrication and Performance of Open Source Generation I and II Compliant Hydrodynamic Gas Foil Bearings

    NASA Technical Reports Server (NTRS)

    DellaCorte, Christopher; Radil, Kevin C.; Bruckner, Robert J.; Howard, S. Adam

    2007-01-01

    Foil gas bearings are self-acting hydrodynamic bearings made from sheet metal foils comprised of at least two layers. The innermost top foil layer traps a gas pressure film that supports a load while a layer or layers underneath provide an elastic foundation. Foil bearings are used in many lightly loaded, high-speed turbo-machines such as compressors used for aircraft pressurization, and small micro-turbines. Foil gas bearings provide a means to eliminate the oil system leading to reduced weight and enhanced temperature capability. The general lack of familiarity of the foil bearing design and manufacturing process has hindered their widespread dissemination. This paper reviews the publicly available literature to demonstrate the design, fabrication and performance testing of both first and second generation bump style foil bearings. It is anticipated that this paper may serve as an effective starting point for new development activities employing foil bearing technology.

  10. Consequences of FOIL for Undergraduates

    ERIC Educational Resources Information Center

    Koban, Lori; Sisneros-Thiry, Simone

    2015-01-01

    FOIL is a well-known mnemonic that is used to find the product of two binomials. We conduct a large sample (n = 252) observational study of first-year college students and show that while the FOIL procedure leads to the accurate expansion of the product of two binomials for most students who apply it, only half of these students exhibit conceptual…

  11. Rhenium-Foil Witness Cylinders

    NASA Technical Reports Server (NTRS)

    Knight, B. L.

    1992-01-01

    Cylindrical portion of wall of combustion chamber replaced with rhenium foil mounted on holder. Rhenium oxidizes without melting, indicating regions of excess oxidizer in combustion-chamber flow. Rhenium witness foils also useful in detecting excess oxygen and other oxidizers at temperatures between 2,000 and 3,600 degrees F in burner cores of advanced gas-turbine engines.

  12. Foil Gas Thrust Bearings for High-Speed Turbomachinery

    NASA Technical Reports Server (NTRS)

    Edmonds, Brian; DellaCorte, Christopher; Dykas, Brian

    2010-01-01

    A methodology has been developed for the design and construction of simple foil thrust bearings intended for parametric performance testing and low marginal costs, supporting continued development of oil-free turbomachinery. A bearing backing plate is first machined and surface-ground to produce flat and parallel faces. Partial-arc slots needed to retain the foil components are then machined into the plate by wire electrical discharge machining. Slot thicknesses achievable by a single wire pass are appropriate to accommodate the practical range of foil thicknesses, leaving a small clearance in this hinged joint to permit limited motion. The backing plate is constructed from a nickel-based superalloy (Inconel 718) to allow heat treatment of the entire assembled bearing, as well as to permit hightemperature operation. However, other dimensionally stable materials, such as precipitation-hardened stainless steel, can also be used for this component depending on application. The top and bump foil blanks are cut from stacks of annealed Inconel X-750 foil by the same EDM process. The bump foil has several azimuthal slits separating it into five individual bump strips. This configuration allows for variable bump spacing, which helps to accommodate the effects of the varying surface velocity, thermal crowning, centrifugal dishing, and misalignment. Rectangular tabs on the foil blanks fit into the backing plate slots. For this application, a rather traditional set of conventionally machined dies is selected, and bump foil blanks are pressed into the dies for forming. This arrangement produces a set of bump foil dies for foil thrust bearings that provide for relatively inexpensive fabrication of various bump configurations, and employing methods and features from the public domain.

  13. 200 kj copper foil fuses. Final report

    SciTech Connect

    McClenahan, C.R.; Goforth, J.H.; Degnan, J.H.; Henderson, R.M.; Janssen, W.H.

    1980-04-01

    A 200-kJ, 50-kV capacitor bank has been discharged into 1-mil-thick copper foils immersed in fine glass beads. These foils ranged in length from 27 to 71 cm and in width from 15 to 40 cm. Voltage spikes of over 250 kV were produced by the resulting fuse behavior of the foil. Moreover, the current turned off at a rate that was over 6 times the initial bank dI/dt. Full widths at half maxima for the voltage and dI/dt spikes were about 0.5 microsec, with some as short as 300 nanosec. Electrical breakdown was prevented in all but one size fuze with maximum applied fields of 7 kV/cm. Fuses that were split into two parallel sections have been tested, and the effects relative to one-piece fuses are much larger than would be expected on the basis of inductance differences alone. A resistivity model for copper foil fuses, which differs from previous work in that it includes a current density dependence, has been devised. Fuse behavior is predicted with reasonable accuracy over a wide range of foil sizes by a quasi-two-dimensional fuse code that incorporates this resistivity model. A variation of Maisonnier's method for predicting optimum fuze size has been derived. This method is valid if the risetime of the bank exceeds 3 microsec, in which case it can be expected to be applicable over a wide range of peak current densities.

  14. Neutron Activation Foil and Thermoluminescent Dosimeter Responses to a Polyethylene Reflected Pulse of the CEA Valduc SILENE Critical Assembly

    SciTech Connect

    Miller, Thomas Martin; Celik, Cihangir; McMahan, Kimberly L.; Lee, Yi-kang; Gagnier, Emmanuel; Authier, Nicolas; Piot, Jerome; Jacquet, Xavier; Rousseau, Guillaume; Reynolds, Kevin H.

    2016-09-01

    This benchmark experiment was conducted as a joint venture between the US Department of Energy (DOE) and the French Commissariat à l'Energie Atomique (CEA). Staff at the Oak Ridge National Laboratory (ORNL) in the US and the Centre de Valduc in France planned this experiment. The experiment was conducted on October 19, 2010 in the SILENE critical assembly facility at Valduc. Several other organizations contributed to this experiment and the subsequent evaluation, including CEA Saclay, Lawrence Livermore National Laboratory (LLNL), the Y-12 National Security Complex (NSC), Babcock International Group in the United Kingdom, and Los Alamos National Laboratory (LANL). The goal of this experiment was to measure neutron activation and thermoluminescent dosimeter (TLD) doses from a source similar to a fissile solution critical excursion. The resulting benchmark can be used for validation of computer codes and nuclear data libraries as required when performing analysis of criticality accident alarm systems (CAASs). A secondary goal of this experiment was to qualitatively test performance of two CAAS detectors similar to those currently and formerly in use in some US DOE facilities. The detectors tested were the CIDAS MkX and the Rocky Flats NCD-91. The CIDAS detects gammas with a Geiger-Muller tube and the Rocky Flats detects neutrons via charged particles produced in a thin 6LiF disc depositing energy in a Si solid state detector. These detectors were being evaluated to determine whether they would alarm, so they were not expected to generate benchmark quality data.

  15. Neutron Activation Foil and Thermoluminescent Dosimeter Responses to a Lead Reflected Pulse of the CEA Valduc SILENE Critical Assembly

    SciTech Connect

    Miller, Thomas Martin; Celik, Cihangir; Isbell, Kimberly McMahan; Lee, Yi-kang; Gagnier, Emmanuel; Authier, Nicolas; Piot, Jerome; Jacquet, Xavier; Rousseau, Guillaume; Reynolds, Kevin H.

    2016-09-01

    This benchmark experiment was conducted as a joint venture between the US Department of Energy (DOE) and the French Commissariat à l'Energie Atomique (CEA). Staff at the Oak Ridge National Laboratory (ORNL) in the US and the Centre de Valduc in France planned this experiment. The experiment was conducted on October 13, 2010 in the SILENE critical assembly facility at Valduc. Several other organizations contributed to this experiment and the subsequent evaluation, including CEA Saclay, Lawrence Livermore National Laboratory (LLNL), the Y-12 National Security Complex (NSC), Babcock International Group in the United Kingdom, and Los Alamos National Laboratory (LANL). The goal of this experiment was to measure neutron activation and thermoluminescent dosimeter (TLD) doses from a source similar to a fissile solution critical excursion. The resulting benchmark can be used for validation of computer codes and nuclear data libraries as required when performing analysis of criticality accident alarm systems (CAASs). A secondary goal of this experiment was to qualitatively test performance of two CAAS detectors similar to those currently and formerly in use in some US DOE facilities. The detectors tested were the CIDAS MkX and the Rocky Flats NCD-91. The CIDAS detects gammas with a Geiger-Muller tube, and the Rocky Flats detects neutrons via charged particles produced in a thin 6LiF disc, depositing energy in a Si solid-state detector. These detectors were being evaluated to determine whether they would alarm, so they were not expected to generate benchmark quality data.

  16. Transverse Emittance Reduction with Tapered Foil

    SciTech Connect

    Jiao, Yi; Chao, Alex; Cai, Yunhai; /SLAC

    2011-12-09

    electron linac or electron beam line, the energy spread increase and angular growth due to multiple scattering are not trivial; as a result, the transverse emittance can only be reduced with a limited ratio, e.g. down to about 65% the original value. The contents of this paper are arranged as follows. In Sec. II, we build the physical model of the tapered foil, derive the transverse eigen emittance and discuss the emittance reduction criteria. In Sec. III, we implement numerical simulations to verify the physical model; and in Sec. IV, we present numerical experiments and subsequent beam line to remove the transverse energy gradient to demonstrate the applicability of such method. Conclusions are given in the last section.

  17. Mock-up experiment at Birmingham University for BNCT project of Osaka University--Neutron flux measurement with gold foil.

    PubMed

    Tamaki, S; Sakai, M; Yoshihashi, S; Manabe, M; Zushi, N; Murata, I; Hoashi, E; Kato, I; Kuri, S; Oshiro, S; Nagasaki, M; Horiike, H

    2015-12-01

    Mock-up experiment for development of accelerator based neutron source for Osaka University BNCT project was carried out at Birmingham University, UK. In this paper, spatial distribution of neutron flux intensity was evaluated by foil activation method. Validity of the design code system was confirmed by comparing measured gold foil activities with calculations. As a result, it was found that the epi-thermal neutron beam was well collimated by our neutron moderator assembly. Also, the design accuracy was evaluated to have less than 20% error.

  18. Drag on swimming flexible foils

    NASA Astrophysics Data System (ADS)

    Raspa, Veronica; Ramananarivo, Sophie; Thiria, Benjamin; Godoy-Diana, Ramiro

    2013-11-01

    We study experimentally the swimming dynamics of thin flexible foils in a self-propelled configuration. Measurements of swimming speed and propulsive force are performed, together with full recordings of the elastic wave kinematics and particle image velocimetry around the swimming foils. We discuss the general problem of drag in undulatory swimming using a bluff-body type model. Our results suggest that a major contribution to the total drag is due to the trailing longitudinal vortices that roll-up on the lateral edges of the foil. Additionally, changing the aspect ratio of the foils allows us to discuss quantitatively the role of the added mass term in Lighthill's elongated-body theory for thrust production in undulatory swimming. We acknowledge support by EADS Foundation through project ``Fluids and elasticity in biomimetic propulsion.''

  19. A novel method for the activity measurement of large-area beta reference sources.

    PubMed

    Stanga, D; De Felice, P; Keightley, J; Capogni, M; Ioan, M R

    2016-03-01

    A novel method has been developed for the activity measurement of large-area beta reference sources. It makes use of two emission rate measurements and is based on the weak dependence between the source activity and the activity distribution for a given value of transmission coefficient. The method was checked experimentally by measuring the activity of two ((60)Co and (137)Cs) large-area reference sources constructed from anodized aluminum foils. Measurement results were compared with the activity values measured by gamma spectrometry. For each source, they agree within one standard uncertainty and also agree within the same limits with the certified values of the source activity.

  20. Battery equalization active methods

    NASA Astrophysics Data System (ADS)

    Gallardo-Lozano, Javier; Romero-Cadaval, Enrique; Milanes-Montero, M. Isabel; Guerrero-Martinez, Miguel A.

    2014-01-01

    Many different battery technologies are available for the applications which need energy storage. New researches are being focused on Lithium-based batteries, since they are becoming the most viable option for portable energy storage applications. As most of the applications need series battery strings to meet voltage requirements, battery imbalance is an important matter to be taken into account, since it leads the individual battery voltages to drift apart over time, and premature cells degradation, safety hazards, and capacity reduction will occur. A large number of battery equalization methods can be found, which present different advantages/disadvantages and are suitable for different applications. The present paper presents a summary, comparison and evaluation of the different active battery equalization methods, providing a table that compares them, which is helpful to select the suitable equalization method depending on the application. By applying the same weight to the different parameters of comparison, switch capacitor and double-tiered switching capacitor have the highest ratio. Cell bypass methods are cheap and cell to cell ones are efficient. Cell to pack, pack to cell and cell to pack to cell methods present a higher cost, size, and control complexity, but relatively low voltage and current stress in high-power applications.

  1. Simultaneous laser cutting and welding of metal foil to edge of a plate

    DOEpatents

    Pernicka, J.C.; Benson, D.K.; Tracy, C.E.

    1996-03-19

    A method is described for welding an ultra-thin foil to the edge of a thicker sheet to form a vacuum insulation panel comprising the steps of providing an ultra-thin foil having a thickness less than 0.002, providing a top plate having an edge and a bottom plate having an edge, clamping the foil to the edge of the plate wherein the clamps act as heat sinks to distribute heat through the foil, providing a laser, moving the laser relative to the foil and the plate edges to form overlapping weld beads to weld the foil to the plate edges while simultaneously cutting the foil along the weld line formed by the overlapping beads. 7 figs.

  2. Simultaneous laser cutting and welding of metal foil to edge of a plate

    DOEpatents

    Pernicka, John C.; Benson, David K.; Tracy, C. Edwin

    1996-01-01

    A method of welding an ultra-thin foil to the edge of a thicker sheet to form a vacuum insulation panel comprising the steps of providing an ultra-thin foil having a thickness less than 0.002, providing a top plate having an edge and a bottom plate having an edge, clamping the foil to the edge of the plate wherein the clamps act as heat sinks to distribute heat through the foil, providing a laser, moving the laser relative to the foil and the plate edges to form overlapping weld beads to weld the foil to the plate edges while simultaneously cutting the foil along the weld line formed by the overlapping beads.

  3. Recycling of waste of aluminum foil into sheet materials

    SciTech Connect

    Katashinskii, V.P.; Vishnyakov, L.R.; Boiko, P.A.

    1995-07-01

    The principal method of recycling secondary metals, in particular aluminum, is remelting. However, remelting of aluminum swarf, and in particular of foil trimmings, is marked by low effectiveness because of extensive oxidation (in the processing of thin foil loss by oxidation amounts to 80%), low productivity of the metallurgical equipment on account of low volume-weight characteristics of foil trimmings compared with lumpy scrap metal, and high power requirements of metallurgical conversion. The shortcomings of the traditional technology can be eliminated by recycling foil trimmings by methods of powder metallurgy. This eliminates completely remelting and loss of metal by oxidation, simplifies the technological cycle, and reduces power requirements. We investigated the process of recycling aluminum foil marque A6 (GOST 21631-76) 14 and 30 {mu}m thick which is widely used in the food industry. The amount of waste occurring in its production may attain 15% of the annual output. In the initial state the waste of foil for food are trimmings of thin aluminum strip crushed into fragments of arbitrary shape whose maximal size in plan is 5-8 cm. To be processed by methods of powder metallurgy, such waste has to be converted into smaller fragments that fill well the cavity of the die when pressed in closed molds or the deformation zone in rolling or other methods of compaction in open tools.

  4. On the performance of hybrid foil-magnetic bearings

    SciTech Connect

    Heshmat, H.; Chen, H.M.; Walton, J.F. II.

    2000-01-01

    Recent technological advancements make hybridization of the magnetic and foil bearing both possible and extremely attractive. Operation of the foil/magnetic bearings takes advantage of the strengths of each individual bearing while minimizing each others weaknesses. In this paper one possible hybrid foil and magnetic bearing arrangement is investigated and sample design and operating parameters are presented. One of the weaknesses of the foil bearings, like any hydrodynamic bearing, is that contact between the foil bearing and the shaft occurs at rest or at very low speeds and it has low load carrying capacity at low speed. For high speed applications, AMBs are, however, vulnerable to rotor-bending or structural resonances that can easily saturate power amplifiers and make the control system unstable. Since the foil bearing is advantageous for high speed operation with a higher load carrying capacity, and the magnetic bearing is so in low speed range, it is a natural evolution to combine them into a hybrid bearing system thus utilizing the advantages of both. To take full advantage of the foil and magnetic elements comprising a hybrid bearing, it is imperative that the static and dynamic characteristics of each bearing be understood. This paper describes the development of a new analysis technique that was used to evaluate the performance of a class of gas-lubricated journal bearing. Unlike conventional approaches, the solution of the governing hydrodynamic equations dealing with compressible fluid is coupled with the structural resiliency of the bearing surface. The distribution of the fluid film thickness and pressures, as well as the shear stresses in a finite-width journal bearing, are computed. Using the Finite Element (FE) method, the membrane effect of an elastic top foil was evaluated and included in the overall analytical procedure. Influence coefficients were generated to address the elasticity effects of combined top foil and elastic foundation on the

  5. Composite metal foil and ceramic fabric materials

    DOEpatents

    Webb, Brent J.; Antoniak, Zen I.; Prater, John T.; DeSteese, John G.

    1992-01-01

    The invention comprises new materials useful in a wide variety of terrestrial and space applications. In one aspect, the invention comprises a flexible cloth-like material comprising a layer of flexible woven ceramic fabric bonded with a layer of metallic foil. In another aspect, the invention includes a flexible fluid impermeable barrier comprising a flexible woven ceramic fabric layer having metal wire woven therein. A metallic foil layer is incontinuously welded to the woven metal wire. In yet another aspect, the invention includes a material comprising a layer of flexible woven ceramic fabric bonded with a layer of an organic polymer. In still another aspect, the invention includes a rigid fabric structure comprising a flexible woven ceramic fabric and a resinous support material which has been hardened as the direct result of exposure to ultraviolet light. Inventive methods for producing such material are also disclosed.

  6. Composite metal foil and ceramic fabric materials

    DOEpatents

    Webb, B.J.; Antoniak, Z.I.; Prater, J.T.; DeSteese, J.G.

    1992-03-24

    The invention comprises new materials useful in a wide variety of terrestrial and space applications. In one aspect, the invention comprises a flexible cloth-like material comprising a layer of flexible woven ceramic fabric bonded with a layer of metallic foil. In another aspect, the invention includes a flexible fluid impermeable barrier comprising a flexible woven ceramic fabric layer having metal wire woven therein. A metallic foil layer is incontinuously welded to the woven metal wire. In yet another aspect, the invention includes a material comprising a layer of flexible woven ceramic fabric bonded with a layer of an organic polymer. In still another aspect, the invention includes a rigid fabric structure comprising a flexible woven ceramic fabric and a resinous support material which has been hardened as the direct result of exposure to ultraviolet light. Inventive methods for producing such material are also disclosed. 11 figs.

  7. An inexpensive and recyclable silver-foil catalyst for the cyclopropanation of alkenes with diazoacetates under mechanochemical conditions.

    PubMed

    Chen, Longrui; Bovee, Mark O; Lemma, Betsegaw E; Keithley, Kimberlee S M; Pilson, Sara L; Coleman, Michael G; Mack, James

    2015-09-14

    The diastereoselective cyclopropanation of various alkenes with diazoacetate derivatives can be achieved under mechanochemical conditions using metallic silver foil and a stainless-steel vial and ball system. This solvent-free method displays analogous reactivity and selectivity to solution-phase reactions without the need for slow diazoacetate addition or an inert atmosphere. The heterogeneous silver-foil catalyst system is easily recyclable without any appreciable loss of activity or selectivity being observed. The cyclopropanation products were obtained with excellent diastereoselectivities (up to 98:2 d.r.) and in high yields (up to 96 %).

  8. Neutron spectral and angular distribution measurements for 113 and 256 MeV protons on range-thick Al and sup 238 U targets using the foil activation techniques

    SciTech Connect

    Greenwood, L.R.; Intasorn, A.

    1989-07-01

    Second neutron yields, energy spectra, and angular distributions have been measured at seven angles from 0 to 150{degree} for 113 and 256 MeV protons stopped in range-thick targets of aluminum and depleted uranium ({sup 238}U). Thin foil stacks of ten different materials were activated by secondary neutrons at distances of 20--30 cm from the targets. Following each irradiation, 30--40 different activation products were measured by gamma-ray spectroscopy. These activation rates were then used to adjust neutron energy spectra calculated by the HETC computer code. Activation cross sections were taken from ENDF/BV below 20 MeV, from literature values tested in Be(d,n) fields up to 50 MeV, and from proton spallation data and calculations from 50--250 MeV. Spectral adjustments were made with the STAY'SL computer code using a least-squares technique to minimize {chi}{sup 2} for a covariance matrix determined from uncertainties in the measured activities, cross sections, and calculated flux spectra. Neutron scattering effects were estimated from foil packets irradiated at different distances from the target. Proton effects were measured with (p,n) reactions. Systematic differences were found between the adjusted and calculated neutron spectra, namely, that HETC underpredicts the neutron flux at back angles by a factor of 2--3 and slightly overpredicts the flux at forward angles. 19 refs., 23 figs., 13 tabs.

  9. FeN foils by nitrogen ion-implantation

    SciTech Connect

    Jiang, Yanfeng; Wang, Jian-Ping; Al Mehedi, Md; Fu, Engang; Wang, Yongqiang

    2014-05-07

    Iron nitride samples in foil shape (free standing, 500 nm in thickness) were prepared by a nitrogen ion-implantation method. To facilitate phase transformation, the samples were bonded on the substrate followed by a post-annealing step. By using two different substrates, single crystal Si and GaAs, structural and magnetic properties of iron nitride foil samples prepared with different nitrogen ion fluences were characterized. α″-Fe{sub 16}N{sub 2} phase in iron nitride foil samples was obtained and confirmed by the proposed approach. A hard magnetic property with coercivity up to 780 Oe was achieved for the FeN foil samples bonded on Si substrate. The feasibility of using nitrogen ion implantation techniques to prepare FeN foil samples up to 500 nm thickness with a stable martensitic phase under high ion fluences has been demonstrated. A possible mechanism was proposed to explain this result. This proposed method could potentially be an alternative route to prepare rare-earth-free FeN bulk magnets by stacking and pressing multiple free-standing thick α″-Fe{sub 16}N{sub 2} foils together.

  10. Use of ultrasound-activated resorbable poly-D-L-lactide pins (SonicPins) and foil panels (Resorb-X) for horizontal bone augmentation of the maxillary and mandibular alveolar ridges.

    PubMed

    Burger, Brenton W

    2010-07-01

    Horizontal bone augmentation of the maxillary and mandibular alveolar ridges has been conventionally performed using mini titanium alloy screws. The titanium alloy screws are used to fixate corticocancellous block grafts to the recipient site or for tenting the mucoperiosteum to retain particulate bone grafts. Nonresorbable guided tissue regenerative membranes reinforced with titanium have also been developed to use with particulate bone grafts to augment alveolar ridge defects. This report demonstrates the use of resorbable ultrasound-activated pins and resorbable foil panels developed by KLS Martin for augmenting the alveolar ridges with particulate bone grafts.

  11. Measurement of the radon diffusion through a nylon foil for different air humidities

    SciTech Connect

    Mamedov, Fadahat; Štekl, Ivan; Smolek, Karel

    2015-08-17

    The dependency of the radon penetration through a nylon foil on air humidity was measured. Such information is needed for the tracking part of the SuperNEMO detector, which is planned to be shielded against radon by nylon foil and in which the air humidity is not negligible. The long term measurements of radon penetration through nylon foils for different air humidities were performed with the radon diffusion setup constructed at the IEAP, CTU in Prague. The setup consists of two stainless steel hemispheres with Si detector in each of them. Both hemispheres are separated by the tested foil. While the left hemisphere contains high Rn activity, the right part contains only activity caused by the radon penetration through the tested foil. Obtained results of this study with a nylon foil with the thickness of 50 µm are presented.

  12. Measurement of the radon diffusion through a nylon foil for different air humidities

    NASA Astrophysics Data System (ADS)

    Mamedov, Fadahat; Štekl, Ivan; Smolek, Karel

    2015-08-01

    The dependency of the radon penetration through a nylon foil on air humidity was measured. Such information is needed for the tracking part of the SuperNEMO detector, which is planned to be shielded against radon by nylon foil and in which the air humidity is not negligible. The long term measurements of radon penetration through nylon foils for different air humidities were performed with the radon diffusion setup constructed at the IEAP, CTU in Prague. The setup consists of two stainless steel hemispheres with Si detector in each of them. Both hemispheres are separated by the tested foil. While the left hemisphere contains high Rn activity, the right part contains only activity caused by the radon penetration through the tested foil. Obtained results of this study with a nylon foil with the thickness of 50 µm are presented.

  13. Electrospray ionization with aluminum foil: A versatile mass spectrometric technique.

    PubMed

    Hu, Bin; So, Pui-Kin; Yao, Zhong-Ping

    2014-03-19

    In this study, we developed a novel electrospray ionization (ESI) technique based on household aluminum foil (Al foil) and demonstated the desirable features and applications of this technique. Al foil can be readily cut and folded into desired configuration for effective ionization and for holding sample solution in bulk to allowing acquisition of durable ion signals. The present technique was demonstrated to be applicable in analysis of a wide variety of samples, ranging from pure chemical and biological compounds, e.g., organic compounds and proteins, to complex samples in liquid, semi-solid, and solid states, e.g., beverages, skincare cream, and herbal medicines. The inert, hydrophobic and impermeable surface of Al foil allows convenient and effective on-target extraction of solid samples and on-target sample clean-up, i.e., removal of salts and detergents from proteins and peptides, extending ESI device from usually only for sample loading and ionization to including sample processing. Moreover, Al foil is an excellent heat-conductor and highly heat-tolerant, permitting direct monitoring of thermal reactions, e.g., thermal denaturation of proteins. Overall, the present study showed that Al-foil ESI could be an economical and versatile method that allows a wide range of applications.

  14. Cross-section studies of relativistic deuteron reactions on copper by activation method

    NASA Astrophysics Data System (ADS)

    Suchopár, M.; Wagner, V.; Svoboda, O.; Vrzalová, J.; Chudoba, P.; Kugler, A.; Adam, J.; Závorka, L.; Baldin, A.; Furman, W.; Kadykov, M.; Khushvaktov, J.; Solnyshkin, A.; Tsoupko-Sitnikov, V.; Tyutyunnikov, S.

    2015-02-01

    The cross-sections of relativistic deuteron reactions on natural copper were studied in detail by means of activation method. The copper foils were irradiated during experiments with the model spallation targets in the Joint Institute for Nuclear Research. The irradiation of activation samples was performed by beams in the energy range from 1 to 8 GeV. Residual nuclides were measured by the gamma spectrometry. While the EXFOR database contains sets of data for relativistic proton reactions, data for deuteron reactions in this energy range are almost missing. Lack of such experimental cross-section values prevents the use of copper foils from beam integral monitoring. For this reason our experiments focused on their measurement and completely new data were obtained in the energy region where no experimental data have been available so far. The copper monitors with their low sensitivity to fast neutrons will contribute to improvement of the beam integral determination during accelerator-driven system studies.

  15. Neutron activation analysis of biological materials by the monostandard method.

    PubMed

    Takeuchi, T; Shinogi, M

    1979-12-01

    Instrumental neutron activation analysis by the monostandard method has been applied to the analyses of biological NBS standard reference materials; 1571 Orchard Leaves and 1577 Bovine Liver. Aluminum foils containing 0.100% gold or 2.00% cobalt were used as the monostandards. The gamma-ray spectral data were recorded on punched paper tape and were analyzed by a computer assisted data processing. The following 25 elements were determined: Al, Ca, Cl Cu, Mg, Mn, V (by short period irradiation), As, Ba, Br, Co, Cr, Cs, Eu, Fe, Hg, K, La, Na, Rb, Sb, Sc, Se, Sm and Zn (by long period irradiation). The results were compared with the certified values by NBS and the reported values in literatures to prove the reliability and accuracy of the monostandard method.

  16. Carbon foils for space plasma instrumentation

    NASA Astrophysics Data System (ADS)

    Allegrini, F.; Ebert, R. W.; Funsten, H. O.

    2016-05-01

    Carbon foils have been successfully used for several decades in space plasma instruments to detect ions and neutral atoms. These instruments take advantage of two properties of the particle-foil interaction: charge conversion of neutral atoms and/or secondary electron emission. This interaction also creates several adverse effects for the projectile exiting the foil, such as angular scattering and energy straggling, which usually act to reduce the sensitivity and overall performance of an instrument. The magnitude of these effects mainly varies with the incident angle, energy, and mass of the incoming projectile and the foil thickness. In this paper, we describe these effects and the properties of the interaction. We also summarize results from recent studies with graphene foils, which can be made thinner than carbon foils due to their superior strength. Graphene foils may soon replace carbon foils in space plasma instruments and open new opportunities for space research in the future.

  17. [Sunrise gold foil jacket crown].

    PubMed

    Lecardonnel, A

    1989-09-01

    This technique permits the preparation of ceramic jacket crowns made on Sunrise laminated precious metal alloy. The Sunrise foil is gold-colored, made of 99% of precious metals and is 50 microns thick. The die is prepared in order to display a moderate and regular undercut beyond the cervical limit. The margin will be underlined with a red pencil. The Sunrise foil is cut according to predetermined templates. Then the foil is applied without burnishing, according to the technique of jacket crowns on platinum foil only by finger pressure. The double folding on closure is preferably done distally or mesially. Then, the metal base is disinserted, sandblasted with 100 microns aluminum oxide, replaced on its die, and placed in a rubber casing before being placed in the isostatic press, to be subjected to a pressure of 2,000 TSI (14 kg par cm2). Sunrise's orange color reinforces rather subtetly the overall color, making these reconstructions particularly esthetic. The color of the Sunrise metal does not require, therefore a too thick opaque. Any ceramic intended to be fired on a metal base, may be used in respecting its firing protocol. Sunrise, as any other technique of this type, require a careful preparation with a shoulder that has a rounded gingivoaxial line angle. Bridges may be built on the "thimbles" crowns, fitted on Sunrise cores, the pontics being made as a ceramo-metal framework.

  18. Force Generation by Flapping Foils

    NASA Astrophysics Data System (ADS)

    Bandyopadhyay, P. R.; Donnelly, M.

    1996-11-01

    Aquatic animals like fish use flapping caudal fins to produce axial and cross-stream forces. During WW2, German scientists had built and tested an underwater vehicle powered by similar flapping foils. We have examined the forces produced by a pair of flapping foils. We have examined the forced produced by a pair of flapping foils attached to the tail end of a small axisymmetric cylinder. The foils operate in-phase (called waving), or in anti-phase (called clapping). In a low-speed water tunnel, we have undertaken time-dependent measurements of axial and cross-stream forces and moments that are exerted by the vortex shedding process over the entire body. Phase-matched LDV measurements of vorticity-velocity vectors, as well as limited flow visualization of the periodic vortex shedding process have also been carried out. The direction of the induced velocity within a pair of shed vortices determines the nature of the forces produced, viz., thrust or drag or cross-stream forces. The clapping mode produces a widely dispersed symmetric array of vortices which results in axial forces only (thrust and rag). On the other hand, the vortex array is staggered in the waving mode and cross-stream (maneuvering) forces are then generated.

  19. Foil Patches Seal Small Vacuum Leaks

    NASA Technical Reports Server (NTRS)

    Spiegel, Kirk W.; Reed, David W.

    1995-01-01

    Report discloses technique to patch holes in nickel-alloy rocket-engine nozzle parts prior to vacuum brazing. Technique involves lightly spot-welding nickel foil 0.002 in. thick over hole patched, then spot-welding corrosion-resistant steel foil of same thickness over nickel foil. Once patches subject to pressure and temperature of vacuum brazing, nickel foil diffuses to bond with nickel-alloy nozzle, making vacuum-tight seal.

  20. Pu-Zr alloy for high-temperature foil-type fuel

    DOEpatents

    McCuaig, Franklin D.

    1977-01-01

    A nuclear reactor fuel alloy consists essentially of from slightly greater than 7 to about 4 w/o zirconium, balance plutonium, and is characterized in that the alloy is castable and is rollable to thin foils. A preferred embodiment of about 7 w/o zirconium, balance plutonium, has a melting point substantially above the melting point of plutonium, is rollable to foils as thin as 0.0005 inch thick, and is compatible with cladding material when repeatedly cycled to temperatures above 650.degree. C. Neutron reflux densities across a reactor core can be determined with a high-temperature activation-measurement foil which consists of a fuel alloy foil core sandwiched and sealed between two cladding material jackets, the fuel alloy foil core being a 7 w/o zirconium, plutonium foil which is from 0.005 to 0.0005 inch thick.

  1. Performance of Simple Gas Foil Thrust Bearings in Air

    NASA Technical Reports Server (NTRS)

    Bruckner, Robert J.

    2012-01-01

    Foil bearings are self-acting hydrodynamics devices used to support high speed rotating machinery. The advantages that they offer to process fluid lubricated machines include: high rotational speed capability, no auxiliary lubrication system, non-contacting high speed operation, and improved damping as compared to rigid hydrodynamic bearings. NASA has had a sporadic research program in this technology for almost 6 decades. Advances in the technology and understanding of foil journal bearings have enabled several new commercial products in recent years. These products include oil-free turbochargers for both heavy trucks and automobiles, high speed electric motors, microturbines for distributed power generation, and turbojet engines. However, the foil thrust bearing has not received a complimentary level of research and therefore has become the weak link of oil-free turbomachinery. In an effort to both provide machine designers with basic performance parameters and to elucidate the underlying physics of foil thrust bearings, NASA Glenn Research Center has completed an effort to experimentally measure the performance of simple gas foil thrust bearing in air. The database includes simple bump foil supported thrust bearings with full geometry and manufacturing techniques available to the user. Test conditions consist of air at ambient pressure and temperatures up to 500 C and rotational speeds to 55,000 rpm. A complete set of axial load, frictional torque, and rotational speed is presented for two different compliant sub-structures and inter-pad gaps. Data obtained from commercially available foil thrust bearings both with and without active cooling is presented for comparison. A significant observation made possible by this data set is the speed-load capacity characteristic of foil thrust bearings. Whereas for the foil journal bearing the load capacity increases linearly with rotational speed, the foil thrust bearing operates in the hydrodynamic high speed limit. In

  2. Extended foil capacitor with radially spoked electrodes

    DOEpatents

    Foster, James C.

    1990-01-01

    An extended foil capacitor has a conductive disk electrically connected in oncrushing contact to the extended foil. A conductive paste is placed through spaces between radial spokes on the disk to electrically and mechanically connect the extended foil to the disk.

  3. Active Learning Methods

    ERIC Educational Resources Information Center

    Zayapragassarazan, Z.; Kumar, Santosh

    2012-01-01

    Present generation students are primarily active learners with varied learning experiences and lecture courses may not suit all their learning needs. Effective learning involves providing students with a sense of progress and control over their own learning. This requires creating a situation where learners have a chance to try out or test their…

  4. Goal-directed mechanisms that constrain retrieval predict subsequent memory for new "foil" information.

    PubMed

    Vogelsang, David A; Bonnici, Heidi M; Bergström, Zara M; Ranganath, Charan; Simons, Jon S

    2016-08-01

    To remember a previous event, it is often helpful to use goal-directed control processes to constrain what comes to mind during retrieval. Behavioral studies have demonstrated that incidental learning of new "foil" words in a recognition test is superior if the participant is trying to remember studied items that were semantically encoded compared to items that were non-semantically encoded. Here, we applied subsequent memory analysis to fMRI data to understand the neural mechanisms underlying the "foil effect". Participants encoded information during deep semantic and shallow non-semantic tasks and were tested in a subsequent blocked memory task to examine how orienting retrieval towards different types of information influences the incidental encoding of new words presented as foils during the memory test phase. To assess memory for foils, participants performed a further surprise old/new recognition test involving foil words that were encountered during the previous memory test blocks as well as completely new words. Subsequent memory effects, distinguishing successful versus unsuccessful incidental encoding of foils, were observed in regions that included the left inferior frontal gyrus and posterior parietal cortex. The left inferior frontal gyrus exhibited disproportionately larger subsequent memory effects for semantic than non-semantic foils, and significant overlap in activity during semantic, but not non-semantic, initial encoding and foil encoding. The results suggest that orienting retrieval towards different types of foils involves re-implementing the neurocognitive processes that were involved during initial encoding.

  5. Zika Vaccine Development: Flavivirus Foils

    DTIC Science & Technology

    2016-09-01

    Martins, Bavari, Zika Vaccine Development 1 Zika Vaccine Development: Flavivirus Foils Martins KAO, Bavari S. The current Zika virus...contrast, work had been underway for decades on the development of an Ebola virus vaccine , laying the groundwork for a rapid response in 2014. The...broader community’s extensive experience with Dengue virus vaccine development and with the pros and cons of different vaccine platforms has led to

  6. Foil X-ray Mirrors

    NASA Astrophysics Data System (ADS)

    Serlemitsos, Peter J.; Soong, Yang

    1996-09-01

    Nested thin foil reflectors have made possible light weight, inexpensive and fast grazing incidence X-ray mirrors for astronomical spectroscopy over a broad band. These mirrors were developed at Goddard for the US Shuttle program and were flown on NASA's shuttleborne Astro-l mission in December 1990. Presently, the Japan/US collaborative spectroscopic mission ASCA, nearing its third year of successful operation in earth orbit, carries, four such mirrors, weighing less than 40 kg and giving total effective areas of ˜ 1200 and 420 cm2 at l and 8 keV respectively. The ˜ 420 kg observatory is the best possible example of how conical foil mirrors opened areas of research that could not have been otherwise addressed with available resources. In this paper, we will briefly review the development and performance of our first generation foil mirrors. We will also describe progress toward improving their imaging capability to prime them for use in future instruments. Such a goal is highly desirable, if not necessary for this mirror technology to remain competitive for future applications.

  7. A general solution-phase approach to oriented nanostructured films of metal chalcogenides on metal foils: the case of nickel sulfide.

    PubMed

    Zhang, Lizhi; Yu, Jimmy C; Mo, Maosong; Wu, Ling; Li, Quan; Kwong, Kwan Wai

    2004-07-07

    Oriented films of nickel sulfide nanostructures, ranging from hierarchical dendrites to nanobelts and nanorods, were hydrothermally grown on Ni foils. This approach has proven to be a general method for preparing nanostructured metal chalcogenides films on corresponding metal foils.

  8. Laser shock microforming of aluminum foil with fs laser

    NASA Astrophysics Data System (ADS)

    Ye, Yunxia; Feng, Yayun; Xuan, Ting; Hua, Xijun; Hua, Yinqun

    2014-12-01

    Laser shock microforming of Aluminum(Al) foil through fs laser has been researched in this paper. The influences of confining layer, clamping method and impact times on induced dent depths were investigated experimentally. Microstructure of fs laser shock forming Al foil was observed through Transmission electron microscopy (TEM). Under the condition of tightly clamping, the dent depths increase with impact times and finally tend to saturating. Another new confining layer, the main component of which is polypropylene, was applied and the confining effect of it is better because of its higher impedance. TEM results show that dislocation is one of the main deformation mechanisms of fs laser shock forming Al foil. Specially, most of dislocations exist in the form of short and discrete dislocation lines. Parallel straight dislocation slip line also were observed. We analyzed that these unique dislocation arrangements are due to fs laser-induced ultra high strain rate.

  9. Strain hardening in bent copper foils

    NASA Astrophysics Data System (ADS)

    Hayashi, Ichiro; Sato, Masumi; Kuroda, Mitsutoshi

    2011-09-01

    A series of systematic tensile and microbend tests were conducted on copper foil specimens with different thicknesses. The specimens were made of a copper foil having almost unidirectional crystal orientations that was considered to be nearly single-crystal. In order to investigate the effects of slip system interactions, two different crystal orientations relative to the tensile direction were considered in the tests: one is close to coplanar double-slip orientation, and the other is close to the ideal cube orientation (the tensile direction nearly coincides to [0 0 1]) that yields multi-planar multi-slip deformation. We extended the microbend test method to include the reversal of bending, and we attempted to divide the total amount of strain-hardening into isotropic and kinematic hardening components. In the tensile tests, no systematic tendency of size dependence was observed. In the microbend tests, size-dependent kinematic hardening behavior was observed for both the crystal orientations, while size dependence of isotropic hardening was observed only for the multi-planar multi-slip case. We introduce an extended crystal plasticity model that accounts for the effects of the geometrically necessary dislocations (GNDs), which correspond to the spatial gradients of crystallographic slips. Through numerical simulations performed using the model, the origin of the size-dependent behavior observed in the microbend tests is discussed.

  10. The Eroding Foil Switch (EFS) model

    NASA Astrophysics Data System (ADS)

    Brandenburg, John E.; Terry, Robert E.

    1986-01-01

    An analysis of the results of two experiments, the Los Alamos Foil Switch Experiment and the Magnetic Gate Experiment, reveals evidence of mass loss and unexpectedly high temperatures in strongly accelerated aluminum foils. Nonlinear magnetic diffusion theory is analyzed both analytically and numerically and found to give strong concentrations of current density, in a propagating front, for foils thicker than a classical skin depth. This concentrated current front is found to lead to mass erosion and high temperatures in foils undergoing strong acceleration. These results are used to formulate a new model of foil kinematics called the EFS model that features both a rocket (or mass loss) phase, and a snowplow (shock wave) phase after foil disassembly. This model is shown to give good agreement with experimental results.

  11. Foil support structure for large electron guns

    SciTech Connect

    Brucker, J.P.; Rose, E.A.

    1993-08-01

    This paper describes a novel support structure for a vacuum diode used to pump a gaseous laser with an electron beam. Conventional support structures are designed to hold a foil flat and rigid. This new structure takes advantage of the significantly greater strength of metals in pure tension, utilizing curved shapes for both foil and support structure. The shape of the foil is comparable to the skin of a balloon, and the shape of the support structures is comparable to the cables of a suspension bridge. This design allows a significant reduction in foil thickness and support structure mass, resulting in a lower electron-beam loss between diode and laser gas. In addition, the foil is pre-formed in the support structure at pressures higher than operating pressure. Therefore, the foil is operated far from the yield point. Increased reliability is anticipated.

  12. Foil bearing research at Penn State

    NASA Technical Reports Server (NTRS)

    Carpino, Marc

    1993-01-01

    Foil journal bearings consist of a compliant metal shell or foil which supports a rigid journal by means of a fluid film. Foil bearings are considered to be a potential alternative to rolling element or traditional rigid surface bearings in cryogenic turbomachinery applications. The prediction of foil bearing performance requires the coupled solution of the foil deflection and the fluid flow in the bearing clearance between the rotor and the foil. The investigations being conducted in the Department of Mechanical Engineering at Penn State are focused in three areas: theoretical prediction of steady state bearing performance, modeling of the dynamic bearing characteristics to determine performance in rotor systems, and experimental verification of analysis codes. The current status and results from these efforts will be discussed.

  13. Foil assisted replica molding for fabrication of microfluidic devices and their application in vitro.

    PubMed

    Micheal, Issac J; Vidyasagar, Aditya J; Bokara, Kiran Kumar; Mekala, Naveen Kumar; Asthana, Amit; Rao, Ch Mohan

    2014-10-07

    We present a simple, rapid, benchtop, Foil Assisted Rapid Molding (FARM) method for the fabrication of microfluidic devices. This novel technique involves the use of aluminium foil, pen and an X-Y plotter to create semi-circular or plano-concave, shallow microchannels. It is an easy do-it-yourself (DIY) technique for creating a microfluidic device in three simple steps: (1) create a channel design using the CAD software, (2) plot the patterns on aluminium foil and (3) use the reverse of the engraved foil as a mold to create microfluidic devices. In this report, we present a detailed study of the proposed method by varying a range of parameters such as foil thickness, tip material, and tip sizes and by investigating their effect on the creation of channels with varying geometry. Furthermore, we demonstrated the cytocompatibility of these devices in vitro.

  14. Photoelectrocatalytic oxidation of formaldehyde using a Ti/TiO2 foil electrode. Application for its novel and simple photoelectrochemical determination.

    PubMed

    Ojani, Reza; Raoof, Jahan-Bakhsh; Zarei, Ebrahim

    2012-09-15

    It was firstly described, that a TiO(2) film modified titanium foil electrode (Ti/TiO(2)) shows an efficient photoelectrocatalytic activity towards formaldehyde oxidation in a phosphate buffer solution. Ti/TiO(2) foil electrode was prepared by anodizing Ti foil in aqueous solution. Also, this electrode was applied for the hydrodynamic photoamperometry measurement of formaldehyde in the optimum conditions (pH 7.0 as biological pH and bias potential 0.8 V vs. reference electrode). The photoelectrocatalytic oxidation photocurrent of the photoelectrode determined by photoamperometry method was linearly dependent on the formaldehyde concentration and the linearity range obtained was 6.70×10(-4)-1.48×10(-2) mol L(-1). Detection limit was found to be 3.09×10(-4) mol L(-1) (2σ).

  15. Gas Foil Bearing Development Program.

    DTIC Science & Technology

    1981-09-01

    curve For the 12 -Foil Bearing. 58 8 1 0 MEASURED DATA - ~- w 3 0 CALCULATED DATA S2 0 0 10 20 30 40 50 60 70 s0 90 100 LOAD, LB Figure 29. Comparison...Government drawings, specifications, or other data are used for any purpose other than in connection with a definitely related Government procurement...formulated, furnished, or in any way supplied the said drawings, specifications, or other data , is not to be regarded by implication or otherwise as in any

  16. Technical Development Path for Gas Foil Bearings

    NASA Technical Reports Server (NTRS)

    Dellacorte, Christopher

    2016-01-01

    Foil gas bearings are in widespread commercial use in air cycle machines, turbocompressors and microturbine generators and are emerging in more challenging applications such as turbochargers, auxiliary power units and propulsion gas turbines. Though not well known, foil bearing technology is well over fifty years old. Recent technological developments indicate that their full potential has yet to be realized. This paper investigates the key technological developments that have characterized foil bearing advances. It is expected that a better understanding of foil gas bearing development path will aid in future development and progress towards more advanced applications.

  17. Technical Development Path for Foil Gas Bearings

    NASA Technical Reports Server (NTRS)

    DellaCorte, Christopher

    2008-01-01

    Foil gas bearings are in widespread commercial use in air cycle machines, turbocompressors and microturbine generators and are emerging in more challenging applications such as turbochargers, auxiliary power units and propulsion gas turbines. Though not well known, foil bearing technology is well over fifty years old. Recent technological developments indicate that their full potential has yet to be realized. This paper investigates the key technological developments that have characterized foil bearing advances. It is expected that a better understanding of foil gas bearing development path will aid in future development and progress towards more advanced applications.

  18. Preparation of isotopic molybdenum foils utilizing small quantities of material

    NASA Astrophysics Data System (ADS)

    Lipski, A. R.; Lee, L. L.; Liang, J. F.; Mahon, J. C.

    1993-09-01

    A simple method utilizing a small amount of isotopic material for production of molybdenum foils is discussed. An e-gun is used in the procedure. The Mo powder undergoes reduction-sintering and melting-solidifying steps leading to the creation of a metallic droplet suitable for further cold rolling or vacuum deposition.

  19. Numerical modeling of large-area beta sources constructed from anodized-aluminum foils.

    PubMed

    Stanga, D

    2012-09-01

    The numerical modeling of large-area beta sources constructed from anodized-aluminum foils is described in this paper. Based on a realistic model for the activity depth distribution, theoretical lower and upper bounds for the efficiency and the transmission coefficient were calculated and used to analyze the comparison method recommended by ISO 8769 for measuring the surface emission rate. The analysis shows that this method can provide measurement results with relative standard uncertainties smaller than 3% for high energy beta emitters such as (90)Sr-(90)Y, (36)Cl and (204)Tl.

  20. Sensitivity of LDEF foil analyses using ultra-low background germanium vs. large NaI(Tl) multidimensional spectrometers

    SciTech Connect

    Reeves, J.H.; Arthur, R.J.; Brodzinski, R.L.

    1992-06-01

    Cobalt foils and stainless steel samples were analyzed for induced {sup 6O}Co activity with both an ultra-low background germanium gamma-ray spectrometer and with a large NaI(Tl) multidimensional spectrometer, both of which use electronic anticoincidence shielding to reduce background counts resulting from cosmic rays. Aluminum samples were analyzed for {sup 22}Na. The results, in addition to the relative sensitivities and precisions afforded by the two methods, are presented.

  1. Sensitivity of LDEF foil analyses using ultra-low background germanium vs. large NaI(Tl) multidimensional spectrometers

    NASA Technical Reports Server (NTRS)

    Reeves, James H.; Arthur, Richard J.; Brodzinski, Ronald L.

    1993-01-01

    Cobalt foils and stainless steel samples were analyzed for induced Co-60 activity with both an ultra-low background germanium gamma-ray spectrometer and with a large NaI(Tl) multidimensional spectrometer, both of which use electronic anticoincidence shielding to reduce background counts resulting from cosmic rays. Aluminum samples were analyzed for Na-22. The results, in addition to the relative sensitivities and precisions afforded by the two methods, are presented.

  2. Prediction of forming limit strains of thin foils using shim

    NASA Astrophysics Data System (ADS)

    Joshi, Sanket Vivek; Bade, Rohit A.; Narasimhan, K.

    2013-12-01

    Thin foils of metallic alloys find utility in metallic thermal protection systems, such as honeycomb structures. Understanding the formability of these thin foils becomes imperative so as to design accurate tooling and also to ensure mechanical robustness of the honeycomb structures during service. It has been found that, obtaining the precise limit strains of these foils directly using the conventional limiting dome test tooling is difficult, because of the excessive draw in and wrinkling that occurs during the punch travel, resulting in erroneous measurement or prediction of limit strains. To address this issue, the blank over blank stacking methodology was developed, which helped keep the draw-in and wrinkling at negligible and thus acceptable levels. Although the blank over blank stacking methodology offers a way to predict and measure limit strains, the same may not be accurate enough due to the effect the substrate properties may impose on the thin foil. To avoid this effect, a different methodology has been proposed herein, which uses a shim stacked over the blank to avoid draw in of these foil blanks and thus help accurate clamping of the blank between the die and blank holder. It is thus understood that either a critical local or global increase in the thickness of the blank material in and around the draw bead is essential to obtain effective clamping of foil and to avoid draw-in and wrinkling. Although, miniaturized hemispherical dome tests may be beneficial for obtaining limit strains as far as foils are concerned, the methodologies proposed herein provide a route to obtaining the same using available equipment, thus saving resources and time involved in development of new miniaturized testing devices. The forming limit strains of thin foils of IN 718 (inconel) alloy having a thickness of 50μm, C263 (nimonic) alloy having a thickness of 100μm and CP Ti (commercially pure titanium) having a thickness of 200μm have been predicted using this methodology

  3. Application of aluminum and titanium foils in low-energy wide-aperture electron accelerators

    NASA Astrophysics Data System (ADS)

    Bodakin, L. V.; Gusakov, A. I.; Komarov, O. V.; Kosogorov, S. L.; Motovilov, S. A.; Uspenskii, N. A.

    2016-09-01

    We have reported on the results of theoretical and experimental investigations of characteristics of aluminum and titanium foils used in devices to extract electron beams from wide-aperture low-energy accelerators with a high current density. The mechanical properties of foils at different temperatures and the electron beam transmission and absorption coefficients have been compared. The results of analyzing the dependences of the efficiency of the electron beam extraction from accelerators on the type of the electron-optical system, material, and thickness of the foil for various sizes of extraction windows and the same type of the slot support grids have been presented. We have proposed an analytic model for calculating the temperature of the foil in the unit cell of the support grid. The electron transmittance and absorbance, as well as the temperature regimes of the foils, have been calculated using different methods.

  4. Barrier Foil Heating Simulations Using LASNEX

    SciTech Connect

    Ho, D D

    2002-03-12

    It is necessary to place a barrier foil in front of the X-ray converter target to prevent the backstreaming ions. This research note presents the simulations of foil heating using the latest EOS tables. LASNEX simulations are carried out using both DARHT-II and ETA-II beam parameters. Results for all the foils studied here, using the DARHT-II beam parameters, show that the integrated line density along the axis at the end of the 4th pulse remains essentially unchanged even if the foils are heated by beams with relatively small beam spot sizes. The temperature can reach up to 3000 C on graphite foil but can only reach several hundred degree Celsius on Mylar foil. Simulations also show that ETA-II beam can create a ''burn-through'' hole on all the foils except graphite and diamond foils, which may require pre-heat. The threshold beam spot size required for hole formation will be compared with LASNEX simulation for the purpose of code verification.

  5. Chromic acid anodizing of aluminum foil

    NASA Technical Reports Server (NTRS)

    Dursch, H.

    1988-01-01

    The success of the Space Station graphite/epoxy truss structure depends on its ability to endure long-term exposure to the LEO environment, primarily the effects of atomic oxygen and the temperture cycling resulting from the 94 minute orbit. This report describes the development and evaluation of chromic acid anodized (CAA) aluminum foil as protective coatings for these composite tubes. Included are: development of solar absorptance and thermal emittance properties required of Al foil and development of CAA parameters to achieve these optical properties; developing techniques to CAA 25 ft lengths of Al foil; developing bonding processes for wrapping the Al foil to graphite/epoxy tubes; and atomic oxygen testing of the CAA Al foil. Two specifications were developed and are included in the report: Chromic Acid Anodizing of Aluminum Foil Process Specification and Bonding of Anodized Aluminum Foil to Graphite/Epoxy Tubes. Results show that CAA Al foil provides and excellent protective and thermal control coating for the Space Station truss structure.

  6. [Guided bone regeneration beneath titanium foils].

    PubMed

    Otto, Katharina; Schopper, Christian; Ewers, Rolf; Lambrecht, J Thomas

    2004-01-01

    The aim of this study was to examine the clinical and histological bony healing process beneath titanium foils used for guided tissue regeneration as well as of the Frios Algipore graft which was applied with autologous bone. 66 sinus floor elevations were carried out and examined over a period of three years and eight months. A success rate of 64% was recorded with foil incorporation. Complications occurred in form of primary and secondary disturbances in the healing process caused by exposure of the foil. 12 of the 66 foils had to be removed early. In all but one case, the augmented bone material was macroscopically well integrated despite the loss of the foil. Primary stability of the inserted dental implants into the ossified augmented site after operations of the sinus maxillaris was reached in all cases with absence of post-operative complications, and in 94% when there was postoperative exposure of the membrane. Histologically, a thin layer of connective tissue poor in cells but rich in collagen fibers appeared underneath the titanium foil. This was followed by newly-formed bony tissue transforming into osseous lamella parallel to the membrane underneath the new periost. In 65 out of 66 cases a sufficient amount of stable bone was built up locally suggesting good bio-compatibility and barrier function. Further, the foil also provided mechanical rest and supporting function for the space underneath. However, the occurrence of healing complications in 36% of the cases showed a need to improve on the titanium foils.

  7. A Preliminary Foil Gas Bearing Performance Map

    NASA Technical Reports Server (NTRS)

    DellaCorte, Christopher; Radil, Kevin C.; Bruckner, Robert J.; Howard, S. Adam

    2006-01-01

    Recent breakthrough improvements in foil gas bearing load capacity, high temperature tribological coatings and computer based modeling have enabled the development of increasingly larger and more advanced Oil-Free Turbomachinery systems. Successful integration of foil gas bearings into turbomachinery requires a step wise approach that includes conceptual design and feasibility studies, bearing testing, and rotor testing prior to full scale system level demonstrations. Unfortunately, the current level of understanding of foil gas bearings and especially their tribological behavior is often insufficient to avoid developmental problems thereby hampering commercialization of new applications. In this paper, a new approach loosely based upon accepted hydrodynamic theory, is developed which results in a "Foil Gas Bearing Performance Map" to guide the integration process. This performance map, which resembles a Stribeck curve for bearing friction, is useful in describing bearing operating regimes, performance safety margins, the effects of load on performance and limiting factors for foil gas bearings.

  8. Tilted foil polarization of radioactive beam nuclei

    NASA Astrophysics Data System (ADS)

    Goldring, Gvirol

    1992-11-01

    Tilted foil polarization has up to now been mostly applied to nuclear reaction products recoiling out of a target traversed by a primary particle beam. Being a universal phenomenon it can be applied equally well to beams of particles, primary or secondary, radioactive or other. There are however some technical considerations arising from the nature of the beam particles. Radioactive beams are associated with ground state nuclei. They usually have low nuclear spin and as a consequence-as will be shown later-low polarization. Secondary beams are usually low in intensity and do not impose any constraints on the foils they traverse; unlike intense primary heavy ion beams which, if they traverse the foils, essentially limit the foil material to carbon. We review here briefly the tilted foil polarization process and then discuss an experiment with an isomer beam. Finally we review experiments with radioactive beams, past, present and planned for the future.

  9. FULL SIZE U-10MO MONOLITHIC FUEL FOIL AND FUEL PLATE FABRICATION-TECHNOLOGY DEVELOPMENT

    SciTech Connect

    G. A. Moore; J-F Jue; B. H. Rabin; M. J. Nilles

    2010-03-01

    Full-size U10Mo foils are being developed for use in high density LEU monolithic fuel plates. The application of a zirconium barrier layer too the foil is applied using a hot co-rolling process. Aluminum clad fuel plates are fabricated using Hot Isostatic Pressing (HIP) or a Friction Bonding (FB) process. An overview is provided of ongoing technology development activities, including: the co-rolling process, foil shearing/slitting and polishing, cladding bonding processes, plate forming, plate-assembly swaging, and fuel plate characterization. Characterization techniques being employed include, Ultrasonic Testing (UT), radiography, and microscopy.

  10. Magnetic shape memory effect in thin foils

    NASA Astrophysics Data System (ADS)

    Heczko, Oleg; Soroka, Aleksandr; Hannula, Simo-Pekka

    2008-07-01

    The magnetic shape memory (MSM) effect was observed in Ni-Mn-Ga freestanding thin foils down to 90μm in thickness using top-down approach. The foils were prepared by thinning the bulk crystals exhibiting MSM effect. The effect was evaluated from the magnetization curves. The significant decrease in magnetic field needed to initiate the MSM effect (magnetic field induced strain or martensite structure reorientation) was observed for the studied foils down to μ0H=0.088T or H =70kA/m. Observation suggests that the pinning of twin boundaries on the internal obstacles rather than pinning on surface lowers twin boundaries' mobility.

  11. Thin layer chromatography-spray mass spectrometry: a method for easy identification of synthesis products and UV filters from TLC aluminum foils.

    PubMed

    Himmelsbach, Markus; Waser, Mario; Klampfl, Christian W

    2014-06-01

    A straightforward procedure for direct mass spectrometric (MS) analysis of spots from thin layer chromatography (TLC) plates, without the need of an external ion source, was developed using the aluminum plate backing as spray tip. The spots were cut out shaped as a tip with a 60° angle, mounted in front of the MS orifice, and after addition of a spray solvent spectra were obtained immediately. A high-resolution time-of-flight MS was used since the method is of particular interest for rapid identification or confirmation of spots from TLC plates. The practical benefits of this technique were demonstrated by detection of by-products of organic reactions, by identification of degradation products, and by accurate confirmation of spots when UV filters in sunscreens were analyzed by TLC. Employing the described method TLC spots can be evaluated fast without the need of an external ion source or devices for analyte transfer from TLC to MS, only a basic MS instrument and a high-voltage power supply is required.

  12. μ-Foil Polymer Electrode Array for Intracortical Neural Recordings.

    PubMed

    Ejserholm, Fredrik; Köhler, Per; Granmo, Marcus; Schouenborg, Jens; Bengtsson, Martin; Wallman, Lars

    2014-01-01

    We have developed a multichannel electrode array-termed [Formula: see text]-foil-that comprises ultrathin and flexible electrodes protruding from a thin foil at fixed distances. In addition to allowing some of the active sites to reach less compromised tissue, the barb-like protrusions that also serves the purpose of anchoring the electrode array into the tissue. This paper is an early evaluation of technical aspects and performance of this electrode array in acute in vitro/in vivo experiments. The interface impedance was reduced by up to two decades by electroplating the active sites with platinum black. The platinum black also allowed for a reduced phase lag for higher frequency components. The distance between the protrusions of the electrode array was tailored to match the architecture of the rat cerebral cortex. In vivo acute measurements confirmed a high signal-to-noise ratio for the neural recordings, and no significant crosstalk between recording channels.

  13. Mechanical design and vibro-acoustic testing of ultrathin carbon foils for a spacecraft instrument

    SciTech Connect

    Bernardin, John D; Baca, Allen G

    2009-01-01

    IBEX-Hi is an electrostatic analyzer spacecraft instrument designed to measure the energy and flux distribution of energetic neutral atoms (ENAs) emanating from the interaction zone between the Earth's solar system and the Milky Way galaxy. A key element to this electro-optic instrument is an array of fourteen carbon foils that are used to ionize the ENAs. The foils are comprised of an ultrathin (50-100 {angstrom} thick) layer of carbon suspended across the surface of an electroformed Nickel wire screen, which in turn is held taught by a metal frame holder. The electro formed orthogonal screen has square wire elements, 12.7 {micro}m thick, with a pitch of 131.1 wires/cm. Each foil holder has an open aperture approximately 5 cm by 2.5 cm. Designing and implementing foil holders with such a large surface area has not been attempted for spaceflight in the past and has proven to be extremely challenging. The delicate carbon foils are subject to fatigue failure from the large acoustic and vibration loads that they will be exposed to during launch of the spacecraft. This paper describes the evolution of the foil holder design from previous space instrument applications to a flight-like IBEX-Hi prototype. Vibro-acoustic qualification tests of the IBEX-Hi prototype instrument and the resulting failure of several foils are summarized. This is followed by a discussion of iterative foil holder design modifications and laser vibrometer modal testing to support future fatigue failure analyses, along with additional acoustic testing of the IBEX-Hi prototype instrument. The results of these design and testing activities are merged and the resulting flight-like foil holder assembly is proposed.

  14. The flow around a flapping foil

    NASA Astrophysics Data System (ADS)

    Mandujano, Francisco; Malaga, Carlos

    2016-11-01

    The flow around a two-dimensional flapping foil immersed in a uniform stream is studied numerically using a Lattice-Boltzmann model, for Reynolds numbers between 100 and 250, and flapping Strouhal numbers between 0 . 01 and 0 . 6 . The computation of the hydrodynamic force on the foil is related to the wake structure. When the foil's is fixed in space, numerical results suggest a relation between drag coefficient behaviour and the flapping frequency which determines the transition from the von Kármán to the inverted von Kármán wake. When the foil is free of translational motion up-stream swimming at constant speed is observed at certain values of the flapping Strouhal. This work was partially supported by UNAM-DGAPA-PAPIIT Grant Number IN115316.

  15. Bonded Invar Clip Removal Using Foil Heaters

    NASA Technical Reports Server (NTRS)

    Pontius, James T.; Tuttle, James G.

    2009-01-01

    A new process uses local heating and temperature monitoring to soften the adhesive under Invar clips enough that they can be removed without damaging the composite underneath or other nearby bonds. Two 1x1 in. (approx.2.5x2.5 cm), 10-W/sq in. (approx.1.6-W/sq cm), 80-ohm resistive foil Kapton foil heaters, with pressure-sensitive acrylic adhesive backing, are wired in parallel to a 50-V, 1-A limited power supply. At 1 A, 40 W are applied to the heater pair. The temperature is monitored in the clip radius and inside the tube, using a dual thermocouple readout. Several layers of aluminum foil are used to speed the heat up, allowing clips to be removed in less than five minutes. The very local heating via the foil heaters allows good access for clip removal and protects all underlying and adjacent materials.

  16. Radiative Cooling With Pigmented Polyethylene Foils

    NASA Astrophysics Data System (ADS)

    Niklasson, Gunnar A.; Eriksson, Tord S.

    1989-03-01

    Polyethylene foils containing a nonabsorbing pigment can be suitable for radiative cooling because of their high reflectance of solar radiation combined with a high transmittance in the atmospheric window region in the thermal infrared. We have studied the optical properties in the wavelength range 0.3-50 μm of extruded polyethylene foils containing various amounts of 0.23 μm diameter Ti02 particles. It appears that the foils can prevent heating of an underlying material, even when directly illuminated by the sun. The total transmittance and reflectance of the Ti02-polyethylene foils were compared with multiple scattering calculations. Lorenz-Mie theory was used to model the scattering and absorption of a single TiO2 sphere. The single scattering parameters were then introduced into the four flux theory, by which the transmittance and reflectance were calculated. We find a satisfactory agreement between theory and experiments in most cases.

  17. Dual scattering foil design for poly-energetic electron beams.

    PubMed

    Kainz, K K; Antolak, J A; Almond, P R; Bloch, C D; Hogstrom, K R

    2005-03-07

    The laser wakefield acceleration (LWFA) mechanism can accelerate electrons to energies within the 6-20 MeV range desired for therapy application. However, the energy spectrum of LWFA-generated electrons is broad, on the order of tens of MeV. Using existing laser technology, the therapeutic beam might require a significant energy spread to achieve clinically acceptable dose rates. The purpose of this work was to test the assumption that a scattering foil system designed for a mono-energetic beam would be suitable for a poly-energetic beam with a significant energy spread. Dual scattering foil systems were designed for mono-energetic beams using an existing analytical formalism based on Gaussian multiple-Coulomb scattering theory. The design criterion was to create a flat beam that would be suitable for fields up to 25 x 25 cm2 at 100 cm from the primary scattering foil. Radial planar fluence profiles for poly-energetic beams with energy spreads ranging from 0.5 MeV to 6.5 MeV were calculated using two methods: (a) analytically by summing beam profiles for a range of mono-energetic beams through the scattering foil system, and (b) by Monte Carlo using the EGS/BEAM code. The analytic calculations facilitated fine adjustments to the foil design, and the Monte Carlo calculations enabled us to verify the results of the analytic calculation and to determine the phase-space characteristics of the broadened beam. Results showed that the flatness of the scattered beam is fairly insensitive to the width of the input energy spectrum. Also, results showed that dose calculated by the analytical and Monte Carlo methods agreed very well in the central portion of the beam. Outside the useable field area, the differences between the analytical and Monte Carlo results were small but significant, possibly due to the small angle approximation. However, these did not affect the conclusion that a scattering foil system designed for a mono-energetic beam will be suitable for a poly

  18. A free-standing thin foil bolometer for measuring soft x-ray fluence.

    PubMed

    Hu, Qingyuan; Ning, Jiamin; Ye, Fan; Meng, Shijian; Xu, Rongkun; Yang, Jianlun; Chu, Yanyun; Qin, Yi; Fu, Yuecheng; Chen, Faxin; Xu, Zeping

    2016-10-01

    A free-standing thin foil bolometer for measuring soft x-ray fluence in z-pinch experiments is developed. For the first time, we present the determination of its sensitivity by different methods. The results showed great consistency for the different methods, which confirms the validity of the sensitivity and provides confidence for its application in z-pinch experiments. It should be highlighted that the sensitivity of a free-standing foil bolometer could be calibrated directly using Joule heating without any corrections that will be necessary for a foil bolometer with substrate because of heat loss. The difference of the waveforms between the free-standing foil bolometer and that with substrate is obvious. It reveals that the heat loss to the substrate should be considered for the latter in despite of the short x-ray pulse when the peak value is used to deduce the total deposited energy. The quantitative influence is analyzed through a detailed simulation.

  19. A free-standing thin foil bolometer for measuring soft x-ray fluence

    NASA Astrophysics Data System (ADS)

    Hu, Qingyuan; Ning, Jiamin; Ye, Fan; Meng, Shijian; Xu, Rongkun; Yang, Jianlun; Chu, Yanyun; Qin, Yi; Fu, Yuecheng; Chen, Faxin; Xu, Zeping

    2016-10-01

    A free-standing thin foil bolometer for measuring soft x-ray fluence in z-pinch experiments is developed. For the first time, we present the determination of its sensitivity by different methods. The results showed great consistency for the different methods, which confirms the validity of the sensitivity and provides confidence for its application in z-pinch experiments. It should be highlighted that the sensitivity of a free-standing foil bolometer could be calibrated directly using Joule heating without any corrections that will be necessary for a foil bolometer with substrate because of heat loss. The difference of the waveforms between the free-standing foil bolometer and that with substrate is obvious. It reveals that the heat loss to the substrate should be considered for the latter in despite of the short x-ray pulse when the peak value is used to deduce the total deposited energy. The quantitative influence is analyzed through a detailed simulation.

  20. Pyrophoric Nanoparticles and Nanoporous Foils for Defense Applications

    DTIC Science & Technology

    2008-12-01

    1 PYROPHORIC NANOPARTICLES AND NANOPOROUS FOILS FOR DEFENSE APPLICATIONS Rajesh Shende , Zac Doorenbos, Alok Vats, and Jan Puszynski* South...metal and method or preparing, US Patent 4895609, January 2, 1990. [13] Shende , R.V., Vats, A., Doorenbos, Z. D., Kapoor, D., Martin, D...Chemical Propulsion, Kyoto, Japan, Sep. 17-21 (to be published). [14] Shende , R.V., Vats, A., Doorenbos, Z. D., Kapoor, D., Haines, C., Martin, D

  1. Reduction of Viologen Bisphosphonate Dihalide with Aluminum Foil

    NASA Astrophysics Data System (ADS)

    Abeta Iyere, Peter

    1996-05-01

    An elegant undergraduate experiment similar to the popular "Iodine Clock Reaction" employs the reduction of methyl viologen by hydroxide ion. A major problem with the hydroxide reduction demonstration is that the mechanism is complicated by the existence of competing reaction pathways. It has been suggested that layered metal viologen phosphonates could be used in the design and construction of molecular materials. The active unit in the reversible photocoloration of these layered materials is the viologen bisphosphonate dihalide (VPX). During our study of these phoshponate systems, we discovered the reduction of viologen bisphosphonate dihalide by aluminum foil, mossy zinc, or magnesium turnings in dilute aqueous hydrofluoric acid solution. When we demonstrated this phenomenon with aluminum foil and VPBr in the classroom, the response of our students was enthusiastic. This demonstration can be used as prelaboratory discussion for an undergraduate kinetic experiment based on the same phenomenon.

  2. Gas Foil Bearing Technology Advancements for Closed Brayton Cycle Turbines

    NASA Technical Reports Server (NTRS)

    Howard, Samuel A.; Bruckner, Robert J.; DellaCorte, Christopher; Radil, Kevin C.

    2007-01-01

    Closed Brayton Cycle (CBC) turbine systems are under consideration for future space electric power generation. CBC turbines convert thermal energy from a nuclear reactor, or other heat source, to electrical power using a closed-loop cycle. The operating fluid in the closed-loop is commonly a high pressure inert gas mixture that cannot tolerate contamination. One source of potential contamination in a system such as this is the lubricant used in the turbomachine bearings. Gas Foil Bearings (GFB) represent a bearing technology that eliminates the possibility of contamination by using the working fluid as the lubricant. Thus, foil bearings are well suited to application in space power CBC turbine systems. NASA Glenn Research Center is actively researching GFB technology for use in these CBC power turbines. A power loss model has been developed, and the effects of a very high ambient pressure, start-up torque, and misalignment, have been observed and are reported here.

  3. Synchronization and Phase Dynamics of Oscillating Foils

    NASA Astrophysics Data System (ADS)

    Finkel, Cyndee L.

    In this work, a two-dimensional model representing the vortices that animals produce, when they are ying/swimming, was constructed. A D{shaped cylinder and an oscillating airfoil were used to mimic these body{shed and wing{generated vortices, respectively. The parameters chosen are based on the Reynolds numbers similar to that which is observed in nature (˜10 4). In order to imitate the motion of ying/swimming, the entire system was suspended into a water channel from frictionless air{bearings. The position of the apparatus in the channel was regulated with a linear, closed loop PI controller. Thrust/drag forces were measured with strain gauges and particle image velocimetry (PIV) was used to examine the wake structure that develops. The Strouhal number of the oscillating airfoil was compared to the values observed in nature as the system transitions between the accelerated and steady states. The results suggest that self-regulation restricts the values of the Strouhal number to a certain range where no other external sensory input is necessary. As suggested by previous work, this self-regulation is a result of a limit cycle process that stems from nonlinear periodic oscillations. The limit cycles were used to examine the synchronous conditions due to the coupling of the foil and wake vortices. Noise is a factor that can mask details of the synchronization. In order to control its effect, we study the locking conditions using an analytic technique that only considers the phases. Our results show that the phase locking indices are dependent on the Strouhal value as it converges to a frequency locking ratio of ≃0:5. This indicates that synchronization occurs during cruising between the motion of the foil and the measured thrust/drag response of the uid forces. The results suggest that Strouhal number selection in steady forward natural swimming and ying is the result of a limit cycle process and not actively controlled by an organism. An implication of this is

  4. Controllable growth and transfer of monolayer MoS2 on Au foils and its potential application in hydrogen evolution reaction.

    PubMed

    Shi, Jianping; Ma, Donglin; Han, Gao-Feng; Zhang, Yu; Ji, Qingqing; Gao, Teng; Sun, Jingyu; Song, Xiuju; Li, Cong; Zhang, Yanshuo; Lang, Xing-You; Zhang, Yanfeng; Liu, Zhongfan

    2014-10-28

    Controllable synthesis of monolayer MoS2 is essential for fulfilling the application potentials of MoS2 in optoelectronics and valleytronics, etc. Herein, we report the scalable growth of high quality, domain size tunable (edge length from ∼ 200 nm to 50 μm), strictly monolayer MoS2 flakes or even complete films on commercially available Au foils, via low pressure chemical vapor deposition method. The as-grown MoS2 samples can be transferred onto arbitrary substrates like SiO2/Si and quartz with a perfect preservation of the crystal quality, thus probably facilitating its versatile applications. Of particular interest, the nanosized triangular MoS2 flakes on Au foils are proven to be excellent electrocatalysts for hydrogen evolution reaction, featured by a rather low Tafel slope (61 mV/decade) and a relative high exchange current density (38.1 μA/cm(2)). The excellent electron coupling between MoS2 and Au foils is considered to account for the extraordinary hydrogen evolution reaction activity. Our work reports the synthesis of monolayer MoS2 when introducing metal foils as substrates, and presents sound proof that monolayer MoS2 assembled on a well selected electrode can manifest a hydrogen evolution reaction property comparable with that of nanoparticles or few-layer MoS2 electrocatalysts.

  5. Mechanical fatigue of thin copper foil

    SciTech Connect

    Merchant, H.D.; Minor, M.G.; Liu, Y.L.

    1999-09-01

    The electrodeposited and the rolled 12 to 35 {micro}m thick copper foils are subjected to the bending/unbending strain-controlled flex fatigue over a wide range of strain amplitudes. The fatigue life is associated with an increase in electrical resistance of the specimen beyond a preassigned threshold. For each foil type, in the rolled or as-deposited as well as in the (recrystallization-like) annealed conditions, the inverse Coffin-Manson (C-M) relationship between strain amplitude ({Delta}{epsilon}/2) and fatigue life (N{sub f}) is established in the high {Delta}{epsilon}/2 (low N{sub f}) and the low {Delta}{epsilon}/2 (high N{sub f}) regimes. The N{sub f}, {Delta}{epsilon}/2, and C-M slopes (c,b) are utilized to calculate the cyclic strain hardening (n{prime}) and fatigue ductility (D{sub f}) parameters. It is shown that for a given foil thickness, an universal relationship exists between D{sub f} and the strength ({sigma}) normalized fatigue life (N{sub f}/{sigma}). The propagation of fatigue crack through the foil thickness and across the sample width is related to the unique fine grain structure for each foil type: pancaked grains for the rolled foil and equiaxed grains for the electrodeposited foil. The fatal failure corresponds to convergence of the through-thickness and the across-the-width fatigue cracks. The variations in (i) electrical resistance, (ii) mid-thickness microhardness and grain structure and (iii) dislocation configurations with fatigue are monitored. Except for a small but significant fatigue induced softening (or hardening), nonconvincing evidence of strain localization (and the associated dislocation configurations generally observed for the bulk samples) has been found.

  6. Ductile failure of a constrained metal foil

    NASA Astrophysics Data System (ADS)

    Varias, A. G.; Suo, Z.; Shih, C. F.

    A METAL foil bonded between stiff ceramic blocks may fail in a variety of ways, including de-adhesion of interfaces, cracking in the ceramics and ductile rupture of the metal. If the interface bond is strong enough to allow the foil to undergo substantial plastic deformation dimples are usually present on fracture surfaces and the nominal fracture energy is enhanced. Ductile fracture mechanisms responsible for such morphology include (i) growth of near-tip voids nucleated at second-phase particles and or interface pores, (ii) cavitation and (iii) interfacial debonding at the site of maximum stress which develops at distances of several foil thicknesses ahead of the crack tip. For a crack in a low to moderately hardening bulk metal, it is known that the maximum mean stress which develops at a distance of several crack openings ahead of the tip does not exceed about three times the yield stress. In contrast, the maximum mean stress that develops at several foil thicknesses ahead of the crack tip in a constrained metal foil can increase continuously with the applied load. Mean stress and interfacial traction of about four to six times the yield of the metal foil can trigger cavitation and/or interfacial debonding. The mechanical fields which bear on the competition between failure mechanisms are obtained by a large deformation finite element analysis. Effort is made to formulate predictive criteria indicating, for a given material system, which one of the several mechanisms operates and the relevant parameters that govern the nominal fracture work. The shielding of the crack tip in the context of ductile adhesive joints, due to the non-proportional deformation in a region of the order of the foil thickness, is also discussed.

  7. Use of Soller slits to remove reference foil fluorescence from transmission spectra.

    PubMed

    Tse, Justin J; George, Graham N; Pickering, Ingrid J

    2011-05-01

    Measurement of X-ray absorption spectroscopy (XAS) in transmission is the method of choice for strong or concentrated samples. In a typical XAS experiment above 5 keV the sample is placed between the first (I(0)) and second (I(1)) ion chambers and a standard foil is placed between the second (I(1)) and third (I(2)) ion chambers for simultaneous calibration of energy during sample analysis. However, some fluorescence from the foil may be registered in I(1), causing anomalies in the transmission signal of the sample, especially when the sample edge jump is relatively small. To remedy this, Soller slits were constructed and placed between the foil and I(1) to minimize back-fluorescence from the foil. A comparison of blank and standard samples, measured with or without Soller slits or under a worst-case scenario, demonstrates the advantages of Soller slits when analyzing weak signal samples via transmission XAS.

  8. One-step synthesis of TiO₂ nanorod arrays on Ti foil for supercapacitor application.

    PubMed

    Zheng, Zhi; Chen, Jiajun; Yoshida, Ryuji; Gao, Xiang; Tarr, Kayla; Ikuhara, Yumi H; Zhou, Weilie

    2014-10-31

    Titanium dioxide (TiO2) nanorod arrays grown directly on Ti metal foil were prepared by a facile one-step hydrothermal method, in which the Ti foil serves as both substrate and precursor. The nanorods are tetragonal rutile single crystal with growth orientation along the [001] direction. The electrochemical properties of the TiO2 nanorod arrays were systematically investigated by cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy using a three-electrode system. As a result, the TiO2 nanorod arrays exhibit good areal specific capacitance and excellent cyclic stability by retaining more than 98% of the initial specific capacitance after 1000 cycles. In addition, a good flexibility of the Ti foil with TiO2 nanorod arrays was demonstrated by the stable electrochemical performance under different bending angles, which indicates that TiO2 nanorod arrays grown on Ti foil could be a promising electrode material for flexible supercapacitor application.

  9. Monte carlo simulation of positron induced secondary electrons in thin carbon foils

    NASA Astrophysics Data System (ADS)

    Cai, L. H.; Yang, B.; Ling, C. C.; Beling, C. D.; Fung, S.

    2011-01-01

    Emission of secondary electrons induced by the passage of low energy positrons through thin carbon foils was studied by the Monte Carlo method. The positron and electron elastic cross sections were calculated by partial wave analysis. The inelastic positron-valence-electron was described by the energy loss function obtained from dielectric theory. The positron-core-electron interaction was modelled by the Gryzinski's excitation function. Positron transport inside the carbon foil was simulated in detail. Secondary electrons created by positrons and high energy secondary electrons through inelastic interactions were tracked through the foil. The positron transmission coefficient and secondary electron yielded in forward and backward geometry are calculated and dependences on positron energy and carbon foil thickness are discussed.

  10. Polarization and collision-induced coherence in the beam-foil light source

    NASA Technical Reports Server (NTRS)

    Liu, C. H.; Bashkin, S.; Church, D. A.

    1974-01-01

    Monatomic systems were excited by the beam-foil method in order to re-examine the possibility that a particular magnetic substate was preferentially populated. O II, Ar II and He I levels were used. The results reveal that: (1) with a tilted foil substantial polarization (up to 15%) may be achieved, (2) the polarization is due to the foil, (3) the foil induces coherence among Zeeman substates with the appearance of quantum beats among these substates and that their coherence is due to the externally applied magnetic field perpendicular to the beam direction, and (4) the angular momentum of the emitted photon is perpendicular to the ion velocity. The possibility for detecting separate effects of alignment and polarization is noted.

  11. Update On The Development, Testing, And Manufacture Of High Density LEU-Foil Targets For The Production Of Mo-99

    SciTech Connect

    Creasy, John T

    2015-05-12

    This project has the objective to reduce and/or eliminate the use of HEU in commerce. Steps in the process include developing a target testing methodology that is bounding for all Mo-99 target irradiators, establishing a maximum target LEU-foil mass, developing a LEU-foil target qualification document, developing a bounding target failure analysis methodology (failure in reactor containment), optimizing safety vs. economics (goal is to manufacture a safe, but relatively inexpensive target to offset the inherent economic disadvantage of using LEU in place of HEU), and developing target material specifications and manufacturing QC test criteria. The slide presentation is organized under the following topics: Objective, Process Overview, Background, Team Structure, Key Achievements, Experiment and Activity Descriptions, and Conclusions. The High Density Target project has demonstrated: approx. 50 targets irradiated through domestic and international partners; proof of concept for two front end processing methods; fabrication of uranium foils for target manufacture; quality control procedures and steps for manufacture; multiple target assembly techniques; multiple target disassembly devices; welding of targets; thermal, hydraulic, and mechanical modeling; robust target assembly parametric studies; and target qualification analysis for insertion into very high flux environment. The High Density Target project has tested and proven several technologies that will benefit current and future Mo-99 producers.

  12. Preparation and investigation of diamond-like carbon stripper foils by filtered cathodic vacuum arc

    NASA Astrophysics Data System (ADS)

    Fan, Qiwen; Du, Yinghui; Zhang, Rong; Xu, Guoji

    2013-04-01

    Thin diamond-like carbon (DLC) stripper foils ˜5 μg/cm2 in thickness were produced and evaluated as heavy-ion strippers for the Beijing HI-13 Tandem Accelerator. The DLC layers ˜4 μg/cm2 in thickness were produced by the filtered cathodic vacuum arc technology onto glass slides coated with betaine-saccharose as releasing agent, which were previously covered with evaporated carbon layers ˜1 μg/cm2 in thickness by the controlled ac arc-discharge method. Irradiation lifetimes of the DLC stripper foils were tested using the heavy-ion beams at the terminal of the Beijing HI-13 Tandem Accelerator, and compared with those of the standard carbon stripper foils made by the combined dc and ac arc-discharge method. The measurements indicate that the DLC stripper foils outlast the standard combined dc and ac arc-discharge carbon stripper foils by a factor of at least 13 and 4for the 197Au- (˜9 MeV, ˜1 μA) and 63Cu- (˜9 MeV, ˜1 μA) ion beams, respectively. The structure and properties of the DLC foils deposited onto silicon substrates by the filtered cathodic vacuum arc technology were also evaluated and analyzed by scanning electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy. The scanning electron microscopy images show that the DLC foils contain hardly droplets through the double 90° filters. The X-ray photoelectron spectrum indicates that sp3 bonds of the DLC foils exceed 70%. The integral intensity ratio of the D peak to the G peak (ID/IG) measured by the Raman spectroscopy is0.78.

  13. Additional security features for optically variable foils

    NASA Astrophysics Data System (ADS)

    Marshall, Allan C.; Russo, Frank

    1998-04-01

    For thousands of years, man has exploited the attraction and radiance of pure gold to adorn articles of great significance. Today, designers decorate packaging with metallic gold foils to maintain the prestige of luxury items such as perfumes, chocolates, wine and whisky, and to add visible appeal and value to wide range of products. However, today's products do not call for the hand beaten gold leaf of the Ancient Egyptians, instead a rapid production technology exists which makes use of accurately coated thin polymer films and vacuum deposited metallic layers. Stamping Foils Technology is highly versatile since several different layers may be combined into one product, each providing a different function. Not only can a foil bring visual appeal to an article, it can provide physical and chemical resistance properties and also protect an article from human forms of interference, such as counterfeiting, copying or tampering. Stamping foils have proved to be a highly effective vehicle for applying optical devices to items requiring this type of protection. Credit cards, bank notes, personal identification documents and more recently high value packaged items such as software and perfumes are protected by optically variable devices applied using stamping foil technology.

  14. Degrader foils for the CARIBU project

    NASA Astrophysics Data System (ADS)

    Greene, John P.; Savard, Guy; Pardo, Richard C.; Baker, Samuel I.; Levand, Anthony F.; Zabransky, Bruce J.

    2011-11-01

    The Californium Rare Ion Breeder Upgrade (CARIBU) project was conceived to provide neutron rich beams originating from the 3% fission decay branch of a 252Cf source to be accelerated by the Argonne Tandem Linear Accelerator System (ATLAS). This 1Ci 252Cf source will be housed in a movable shielded cask, from which it can be directly transferred into a large helium gas stopper cell. Within the gas stopper, the CARIBU 252Cf source is positioned behind an aluminum degrader foil where the radioactive recoils of interest lose most of their energy before being stopped in the helium gas. To stop recoils over the full fission mass range effectively, three degraders of increasing thickness are required, one to cover the light fission peak and two for the isotopes in the heavy fission peak. The geometry of the source within the gas cell would ideally require a hemispherically shaped degrader foil for uniform energy loss of the fission products. The fabrication of a thin foil of such a shape proved to be exceedingly difficult and, therefore, a compromise "top hat" arrangement was designed. In addition, the ultra-high vacuum (UHV) environment necessary for the gas cell to function properly prevented the use of any epoxy due to vacuum outgassing. Handling, assembling of the foils and mounting must be done under clean room conditions. Details of early attempts at producing these foils as well as handling and mounting will be discussed.

  15. Procyon experiments utilizing foil-fuse opening switches

    SciTech Connect

    Rickel, D.G.; Lindemuth, I.R.; Reinovsky, R.E.; Brownell, J.H.; Goforth, J.H.; Greene, A.E.; Kruse, H.W.; Oona, H.; Parker, J.V.; Turchi, P.J.

    1991-01-01

    The Los Alamos National Laboratory has applied the explosive magnetic flux compression generator (FCG) technology to the high-energy foil-implosion project, Trailmaster, to reach energy levels unattainable by other methods under current budget constraints. A required component for FCG systems is a power-conditioning stage that matches the slow risetime of the energy source with the fast-risetime requirements of the foil-implosion load. Currently, the Trailmaster concept is based on a two-step process of combining an intermediate power compression stage with a plasma flow switch (PFS) that will deliver energy to an imploding foil on the order of 100 ns. The intermediate power compression stage, which is the main emphasis of this report, consists of an energy storage inductor loaded by the FCG (the energy sauce) and an associated opening and closing switch. In our Procyon testing series, a subtask of the Trailmaster project, we have explored two approaches for opening and closing switches. One uses an explosive opening switch (EFF) and a detonator-initiated closing switch, the topic of another paper at this conference, and the other a resistive fuse opening switch a surface tracking closing switch (STS), the subject of this presentation. This latter concept was successfully tested last summer with a complete plasma flow switch assembly except the dynamic implosion foil was replaced by a rigid passive inductive load. We present data on the performance of the fuse opening switch, the surface tracking closing switch, and the plasma flow switch. 7 refs., 9 figs.

  16. The investigation of electrolytic surface roughening for PCB copper foil

    NASA Astrophysics Data System (ADS)

    Lee, Shuo-Jen; Liu, Chao-Kai

    2013-10-01

    This study is the application of the principle of electrochemical. The anodic dissolution has no concentration polarization. Hence, electrolyte life is substantially increased. The waste copper is high in ion concentration with a recovery value. As compared with the current PCB chemical pre-treatment method, it may have advantages of cost-saving, improvement of overall efficiency, reduction of production costs and reduction of the amount of waste generated. In the development of the copper foil for electrochemical roughening process, the use of electrolysis reaction affects the copper surface dissolution to form a unique bump coarsening. It will increase in the surface area of the copper foil to improve dry film solder mask and the adhesion between the copper surfaces. Four electrolytes, two neutral salts and two acids, were selected to explore the best of the electrolytic roughening parameters of temperature, time and voltage. The surface roughness and the surface morphology of the copper foil were measured before and after the electrolytic surface roughening. Finally, after repeated experiments, electrolytes A and B copper generates obvious inter-granular corrosion, resulting in a rough surface similar to the chemical pre-treatment. On the other hands, the surface morphology resulted from electrolytes C and D appears more like pitting. Both electrolytic could generate surface roughness of Ra 0.3 um roughened copper surface higher than industrial standard.

  17. Fission foil detector calibrations with high energy protons

    NASA Technical Reports Server (NTRS)

    Benton, E. V.; Frank, A. L.

    1995-01-01

    Fission foil detectors (FFD's) are passive devices composed of heavy metal foils in contact with muscovite mica films. The heavy metal nuclei have significant cross sections for fission when irradiated with neutrons and protons. Each isotope is characterized by threshold energies for the fission reactions and particular energy-dependent cross sections. In the FFD's, fission fragments produced by the reactions are emitted from the foils and create latent particle tracks in the adjacent mica films. When the films are processed surface tracks are formed which can be optically counted. The track densities are indications of the fluences and spectra of neutrons and/or protons. In the past, detection efficiencies have been calculated using the low energy neutron calibrated dosimeters and published fission cross sections for neutrons and protons. The problem is that the addition of a large kinetic energy to the (n,nucleus) or (p,nucleus) reaction could increase the energies and ranges of emitted fission fragments and increase the detector sensitivity as compared with lower energy neutron calibrations. High energy calibrations are the only method of resolving the uncertainties in detector efficiencies. At high energies, either proton or neutron calibrations are sufficient since the cross section data show that the proton and neutron fission cross sections are approximately equal. High energy proton beams have been utilized (1.8 and 4.9 GeV, 80 and 140 MeV) for measuring the tracks of fission fragments emitted backward and forward.

  18. Fission foil detector calibrations with high energy protons

    SciTech Connect

    Benton, E.V.; Frank, A.L.

    1995-03-01

    Fission foil detectors (FFD`s) are passive devices composed of heavy metal foils in contact with muscovite mica films. The heavy metal nuclei have significant cross sections for fission when irradiated with neutrons and protons. Each isotope is characterized by threshold energies for the fission reactions and particular energy-dependent cross sections. In the FFD`s, fission fragments produced by the reactions are emitted from the foils and create latent particle tracks in the adjacent mica films. When the films are processed surface tracks are formed which can be optically counted. The track densities are indications of the fluences and spectra of neutrons and/or protons. In the past, detection efficiencies have been calculated using the low energy neutron calibrated dosimeters and published fission cross sections for neutrons and protons. The problem is that the addition of a large kinetic energy to the (n,nucleus) or (p,nucleus) reaction could increase the energies and ranges of emitted fission fragments and increase the detector sensitivity as compared with lower energy neutron calibrations. High energy calibrations are the only method of resolving the uncertainties in detector efficiencies. At high energies, either proton or neutron calibrations are sufficient since the cross section data show that the proton and neutron fission cross sections are approximately equal. High energy proton beams have been utilized (1.8 and 4.9 GeV, 80 and 140 MeV) for measuring the tracks of fission fragments emitted backward and forward.

  19. A review of progress and challenges in flapping foil power generation

    NASA Astrophysics Data System (ADS)

    Young, John; Lai, Joseph C. S.; Platzer, Max F.

    2014-05-01

    Power may be extracted from a flowing fluid in a variety of ways. Turbines using one or more oscillating foils are under increasingly active investigation, as an alternative to rotary wind turbines and river, oceanic and tidal current water turbines, although industrial development is at a very nascent stage. Such flapping foil turbines promise some key potential advantages, including lower foil velocities (and hence lower noise and wildlife impact), and more effective small-scale and shallow water operation. The role of a number of parameters is investigated, including foil kinematics (modes, frequencies, amplitudes and time histories of motion), foil and system geometry (shape, configuration and structural flexibility), and flow physics effects (Reynolds number and turbulence, shear flows and ground effect). Details of the kinematics are shown to have the single largest influence on power output and efficiency (measured as the ratio of power output to that available and accessible in the fluid stream). The highest levels of power and efficiency are associated with very large foil pitch angles (upwards of 70°) and angles of attack (30-40°), such that the flow is massively separated for much of the flapping cycle, in contrast to rotary turbines which rely on attached flow over as much of the rotor disk as possible. This leads to leading edge vortices comparable in size to the foil chord, and the evolution and interaction of these vortices with the foil as it moves play a central role in determining performance. The other parameters also influence the vortex behaviour, but in general to a lesser degree. Numerous gaps in the research literature and outstanding issues are highlighted.

  20. Conceptual Design and Feasibility of Foil Bearings for Rotorcraft Engines: Hot Core Bearings

    NASA Technical Reports Server (NTRS)

    Howard, Samuel A.

    2007-01-01

    Recent developments in gas foil bearing technology have led to numerous advanced high-speed rotating system concepts, many of which have become either commercial products or experimental test articles. Examples include oil-free microturbines, motors, generators and turbochargers. The driving forces for integrating gas foil bearings into these high-speed systems are the benefits promised by removing the oil lubrication system. Elimination of the oil system leads to reduced emissions, increased reliability, and decreased maintenance costs. Another benefit is reduced power plant weight. For rotorcraft applications, this would be a major advantage, as every pound removed from the propulsion system results in a payload benefit.. Implementing foil gas bearings throughout a rotorcraft gas turbine engine is an important long-term goal that requires overcoming numerous technological hurdles. Adequate thrust bearing load capacity and potentially large gearbox applied radial loads are among them. However, by replacing the turbine end, or hot section, rolling element bearing with a gas foil bearing many of the above benefits can be realized. To this end, engine manufacturers are beginning to explore the possibilities of hot section gas foil bearings in propulsion engines. This overview presents a logical follow-on activity by analyzing a conceptual rotorcraft engine to determine the feasibility of a foil bearing supported core. Using a combination of rotordynamic analyses and a load capacity model, it is shown to be reasonable to consider a gas foil bearing core section. In addition, system level foil bearing testing capabilities at NASA Glenn Research Center are presented along with analysis work being conducted under NRA Cooperative Agreements.

  1. Performance characteristics of pitching flexible foil propulsors

    NASA Astrophysics Data System (ADS)

    Brownell, Cody; Egan, Brendan; Murray, Mark

    2014-11-01

    Performance characteristics of flexible foil propulsors are studied experimentally. The project investigates the dependence of thrust and efficiency on foil elasticity, Strouhal number, and flow velocity. The experiments took place in a large recirculating water channel, using full span flexible propulsor models to approximate a 2D geometry. The propulsor pitched about a fixed axis at its quarter chord, with a six-axis load cell measuring the forces and torques on the shaft. Propulsive efficiency is found to peak at an optimum Strouhal number for each foil tested. Varying elasticity did not produce a similar local maximum over the sampled parameter space. The ensemble data will facilitate the engineering of fish-like propulsion systems for future application of this technology.

  2. Two High-Temperature Foil Journal Bearings

    NASA Technical Reports Server (NTRS)

    Zak, Michail

    2006-01-01

    An enlarged, high-temperature-compliant foil bearing has been built and tested to demonstrate the feasibility of such bearings for use in aircraft gas turbine engines. Foil bearings are attractive for use in some machines in which (1) speeds of rotation, temperatures, or both exceed maximum allowable values for rolling-element bearings; (2) conventional lubricants decompose at high operating temperatures; and/or (3) it is necessary or desirable not to rely on conventional lubrication systems. In a foil bearing, the lubricant is the working fluid (e.g., air or a mixture of combustion gases) in the space between the journal and the shaft in the machine in which the bearing is installed.

  3. Status of Genesis Mo-Pt Foils

    NASA Technical Reports Server (NTRS)

    Nishiizumi, K.; Allton, J. H.; Burnett, D. S.; Butterworth, A. L.; Caffee, M. W.; Clark, B.; Jurewicz, A. J. G.; Komura, K.; Westphal, A. J.; Welten, K. C.

    2005-01-01

    A total of 8,000 sq cm of Mo-coated Pt foils were exposed to solar wind for 884 days by the Genesis mission. Solar wind ions were captured in the surface of the Mo. Our objective is the measurement of long-lived radionuclides, such as Be-10, Al-26, Cl-36, and Mn-53, and short-lived radionuclides, such as Na-22 and Mn-54, in the captured sample of solar wind. The expected flux of these nuclides in the solar wind is 100 atom/sq cm yr or less. The hard landing of the SRC (Sample Return Capsule) at UTTR (Utah Test and Training Range) has resulted in contaminated and crumpled foils. Here we present a status report and revised plan for processing the foils.

  4. Computerized reduction of airborne foil impactor data

    NASA Technical Reports Server (NTRS)

    Peterson, Bret A.; Musil, Dennis J.; Smith, Paul L.

    1991-01-01

    A new technique for reducing data obtained from a foil impactor carried on the T-28 thunderstorm penetration aircraft is described. The technique employs a video-image processing system that was originally developed for satellite imagery and a computer-reduction program that was originally developed for determining cloud-size distributions to count and size particle impressions on the foil. This eliminates the tedious manual processing that has limited the usefulness of such devices, while at the same time improving objectivity. The technique has been applied to foil data acquired in thunderstorms in the southeastern United States during the Cooperative Huntsville Meteorological Experiment, where most of the particles were at least roughly spherical. Its usefulness for storms in which highly irregular or fragile ice particles predominate has yet to be established.

  5. Friction and Wear Characteristics of Cu-4Al Foil Bearing Coating at 25 and 650 degree C

    NASA Technical Reports Server (NTRS)

    Stanford, Malcolm K.; DellaCorte, Christopher

    2004-01-01

    The friction and wear performance of a Cu-4Al top foil coating has been investigated in Generation I foil air bearings. The copper alloy was applied by a novel deposition technique (ion diffusion) and the journal was coated with PS304, a plasma spray deposited high temperature composite solid lubricant coating. The ion diffusion coating process deposits a desirable smooth layer compared to other methods like cathodic arc deposition. The tribological performance of bearings with and without Cu-4Al foil coatings were evaluated through start-stop tests on an air bearing test rig at 25 and 650 C. The results indicate that the Cu-4Al assists during the initial break-in period, gives more stable friction performance with respect to temperature, and appears to prevent top foil wear at high temperature. The measured load capacity coefficient was 0.5, which was comparable to earlier testing of more advanced design Generation III bearings coated with standard cathodic arc deposited Cu-4Al. However, further studies are needed to determine if deeper penetration of the copper alloy into the foil would help make the transition in friction behavior from contact with the Cu-4Al coated foil to contact with the base foil material more gradual. Also, future work is recommended to assess the performance of ion diffusion coatings with different Cu-based alloy compositions and to investigate the effect the coating has on the elastic modulus of the foil material.

  6. Thrust augmentation in tandem flapping foils by foil-wake interaction

    NASA Astrophysics Data System (ADS)

    Anderson, Erik; Lauder, George

    2006-11-01

    Propulsion by pitching and heaving airfoils and hydrofoils has been a focus of much research in the field of biologically inspired propulsion. Organisms that use this sort of propulsion are self-propelled, so it is difficult to use standard experimental metrics such as thrust and drag to characterize performance. We have constructed a flapping foil robot mounted in a flume on air-bearings that allows for the determination of self-propelled speed as a metric of performance. We have used a pair of these robots to examine the impact of an upstream flapping foil on a downstream flapping foil as might apply to tandem fins of a swimming organism or in-line swimming of schooling organisms. Self-propelled speed and a force transducer confirmed significant thrust augmentation for particular foil-to-foil spacings, phase differences, and flapping frequencies. Flow visualization shows the mechanism to be related to the effective angle of attack of the downstream foil due to the structure of the wake of the upstream foil. This confirms recent computational work and the hypotheses by early investigators of fish fluid dynamics.

  7. Compressor ported shroud for foil bearing cooling

    DOEpatents

    Elpern, David G.; McCabe, Niall; Gee, Mark

    2011-08-02

    A compressor ported shroud takes compressed air from the shroud of the compressor before it is completely compressed and delivers it to foil bearings. The compressed air has a lower pressure and temperature than compressed outlet air. The lower temperature of the air means that less air needs to be bled off from the compressor to cool the foil bearings. This increases the overall system efficiency due to the reduced mass flow requirements of the lower temperature air. By taking the air at a lower pressure, less work is lost compressing the bearing cooling air.

  8. Method for facilitating catalyzed oxidation reactions, device for facilitating catalyzed oxidation reactions

    DOEpatents

    Beuhler, Robert J.; White, Michael G.; Hrbek, Jan

    2006-08-15

    A catalytic process for the oxidation of organic. Oxygen is loaded into a metal foil by heating the foil while in contact with an oxygen-containing fluid. After cooling the oxygen-activated foil to room temperature, oxygen diffuses through the foil and oxidizes reactants exposed to the other side of the foil.

  9. Spallation Neutron Source SNS Diamond Stripper Foil Development

    SciTech Connect

    Shaw, Robert W; Plum, Michael A; Wilson, Leslie L; Feigerle, Charles S.; Borden, Michael J.; Irie, Y.; Sugai, I; Takagi, A

    2007-01-01

    Diamond stripping foils are under development for the SNS. Freestanding, flat 300 to 500 {micro}g/cm{sup 2} foils as large as 17 x 25 mm{sup 2} have been prepared. These nano-textured polycrystalline foils are grown by microwave plasma-assisted chemical vapor deposition in a corrugated format to maintain their flatness. They are mechanically supported on a single edge by a residual portion of their silicon growth substrate; fine foil supporting wires are not required for diamond foils. Six foils were mounted on the SNS foil changer in early 2006 and have performed well in commissioning experiments at reduced operating power. A diamond foil was used during a recent experiment where 15 {micro}C of protons, approximately 64% of the design value, were stored in the ring. A few diamond foils have been tested at LANSCE/PSR, where one foil was in service for a period of five months (820 C of integrated injected charge) before it was replaced. Diamond foils have also been tested in Japan at KEK (640 keV H{sup -}) where their lifetimes slightly surpassed those of evaporated carbon foils, but fell short of those for Sugai's new hybrid boron carbon (HBC) foils.

  10. Reactive multilayer synthesis of hard ceramic foils and films

    DOEpatents

    Makowiecki, D.M.; Holt, J.B.

    1996-02-13

    A method is disclosed for synthesizing hard ceramic materials such as carbides, borides and aluminides, particularly in the form of coatings provided on another material so as to improve the wear and abrasion performance of machine tools, for example. The method involves the sputter deposition of alternating layers of reactive metals with layers of carbon, boron, or aluminum and the subsequent reaction of the multilayered structure to produce a dense crystalline ceramic. The material can be coated on a substrate or formed as a foil which can be coiled as a tape for later use.

  11. Reactive multilayer synthesis of hard ceramic foils and films

    DOEpatents

    Makowiecki, Daniel M.; Holt, Joseph B.

    1996-01-01

    A method for synthesizing hard ceramic materials such as carbides, borides nd aluminides, particularly in the form of coatings provided on another material so as to improve the wear and abrasion performance of machine tools, for example. The method involves the sputter deposition of alternating layers of reactive metals with layers of carbon, boron, or aluminum and the subsequent reaction of the multilayered structure to produce a dense crystalline ceramic. The material can be coated on a substrate or formed as a foil which can be coild as a tape for later use.

  12. A new and simple calibration-independent method for measuring the beam energy of a cyclotron.

    PubMed

    Gagnon, Katherine; Jensen, Mikael; Thisgaard, Helge; Publicover, Julia; Lapi, Suzanne; McQuarrie, Steve A; Ruth, Thomas J

    2011-01-01

    This work recommends a new and simple-to-perform method for measuring the beam energy of an accelerator. The proposed method requires the irradiation of two monitor foils interspaced by an energy degrader. The primary advantage of the proposed method, which makes this method unique from previous energy evaluation strategies that employ the use of monitor foils, is that this method is independent of the detector efficiency calibration. This method was evaluated by performing proton activation of (nat)Cu foils using both a cyclotron and a tandem Van de Graaff accelerator. The monitor foil activities were read using a dose calibrator set to an arbitrary calibration setting. Excellent agreement was noted between the nominal and measured proton energies.

  13. The Fluid Foil: The Seventh Simple Machine

    ERIC Educational Resources Information Center

    Mitts, Charles R.

    2012-01-01

    A simple machine does one of two things: create a mechanical advantage (lever) or change the direction of an applied force (pulley). Fluid foils are unique among simple machines because they not only change the direction of an applied force (wheel and axle); they convert fluid energy into mechanical energy (wind and Kaplan turbines) or vice versa,…

  14. Metallic foil-assisted laser cell printing.

    PubMed

    Lin, Yafu; Huang, Yong; Chrisey, Douglas B

    2011-02-01

    Laser direct-write technology such as modified laser-induced forward transfer (LIFT) is emerging as a revolutionary technology for biological construct fabrication. While many modified LIFT-based cell direct writing successes have been achieved, possible process-induced cell injury and death is still a big hurdle for modified LIFT-based cell direct writing to be a viable technology. The objective of this study is to propose metallic foil-assisted LIFT using a four-layer structure to achieve better droplet size control and increase cell viability in direct writing of human colon cancer cells (HT-29). The proposed four layers include a quartz disk, a sacrificial and adhesive layer, a metallic foil, and a cell suspension layer. The bubble formation-induced stress wave is responsible for droplet formation. It is found that the proposed metallic foil-assisted LIFT approach is an effective cell direct-write technology and provides better printing resolution and high post-transfer cell viability when compared with other conventional modified LIFT technologies such as matrix-assisted pulsed-laser evaporation direct-write; at the same time, the possible contamination from the laser energy absorbing material is minimized using a metallic foil.

  15. Hydrogen and Palladium Foil: Two Classroom Demonstrations

    ERIC Educational Resources Information Center

    Klotz, Elsbeth; Mattson, Bruce

    2009-01-01

    In these two classroom demonstrations, students observe the reaction between H[subscript 2] gas and Pd foil. In the first demonstration, hydrogen and palladium combine within one minute at 1 atm and room temperature to yield the non-stoichiometric, interstitial hydride with formula close to the maximum known value, PdH[subscript 0.7]. In the…

  16. Indium Foil Serves As Thermally Conductive Gasket

    NASA Technical Reports Server (NTRS)

    Eastman, G. Yale; Dussinger, Peter M.

    1993-01-01

    Indium foil found useful as gasket to increase thermal conductance between bodies clamped together. Deforms to fill imperfections on mating surfaces. Used where maximum temperature in joint less than melting temperature of indium. Because of low melting temperature of indium, most useful in cryogenic applications.

  17. Strong field electrodynamics of a thin foil

    SciTech Connect

    Bulanov, Sergei V.; Esirkepov, Timur Zh.; Kando, Masaki; Bulanov, Stepan S.; Rykovanov, Sergey G.; Pegoraro, Francesco

    2013-12-15

    Exact solutions describing the nonlinear electrodynamics of a thin double layer foil are presented. These solutions correspond to a broad range of problems of interest for the interaction of high intensity laser pulses with overdense plasmas, such as frequency upshifting, high order harmonic generation, and high energy ion acceleration.

  18. Foil Panel Mirrors for Nonimaging Applications

    NASA Technical Reports Server (NTRS)

    Kuyper, D. J.; Castillo, A. A.

    1984-01-01

    Large durable, lightweight mirrors made by bonding thick aluminum foil to honeycomb panels or other rigid, flat backings. Mirrors suitable for use as infrared shields, telescope doors, solar-furnance doors, advertising displays, or other reflectors that require low thermal emissivity and high specularity but do not require precise surface figure necessary for imaging.

  19. Strong field electrodynamics of a thin foil

    NASA Astrophysics Data System (ADS)

    Bulanov, S. S.; Bulanov, S. V.; Esirkepov, T. Zh.; Kando, M.; Rykovanov, S.; Pegoraro, F.; Schroeder, C. B.; Esarey, E.; Leemans, W. P.

    2017-03-01

    A new one-dimensional analytical model of a thin double layer foil interaction with a laser pulse is presented. It is based on one-dimensional electrodynamics. This model can be used for the study of high intensity laser pulse interactions with overdense plasmas, leading to frequency upshifting, high order harmonic generation, and ion acceleration in different regimes.

  20. 6Li foil thermal neutron detector

    SciTech Connect

    Ianakiev, Kiril D; Swinhoe, Martyn T; Favalli, Andrea; Chung, Kiwhan; Macarthur, Duncan W

    2010-01-01

    In this paper we report on the design of a multilayer thermal neutron detector based on {sup 6}Li reactive foil and thin film plastic scintillators. The {sup 6}Li foils have about twice the intrinsic efficiency of {sup 10}B films and about four times higher light output due to a unique combination of high energy of reaction particles, low self absorption, and low ionization density of tritons. The design configuration provides for double sided readout of the lithium foil resulting in a doubling of the efficiency relative to a classical reactive film detector and generating a pulse height distribution with a valley between neutron and gamma signals similar to {sup 3}He tubes. The tens of microns thickness of plastic scintillator limits the energy deposited by gamma rays, which provides the necessary neutron/gamma discrimination. We used MCNPX to model a multilayer Li foil detector design and compared it with the standard HLNCC-II (18 {sup 3}He tubes operated at 4 atm). The preliminary results of the {sup 6}Li configuration show higher efficiency and one third of the die-away time. These properties, combined with the very short dead time of the plastic scintillator, offer the potential of a very high performance detector.

  1. Tungsten foil laminate for structural divertor applications - Joining of tungsten foils

    NASA Astrophysics Data System (ADS)

    Reiser, Jens; Rieth, Michael; Möslang, Anton; Dafferner, Bernhard; Hoffmann, Jan; Mrotzek, Tobias; Hoffmann, Andreas; Armstrong, D. E. J.; Yi, Xiaoou

    2013-05-01

    This paper is the fourth in our series on tungsten laminates. The aim of this paper is to discuss laminate synthesis, meaning the joining of tungsten foils. It is obvious that the properties of the tungsten laminate strongly depend on the combination of (i) interlayer and (ii) joining technology, as this combination defines (i) the condition of the tungsten foil after joining (as-received or recrystallised) as well as (ii) the characteristics of the interface between the tungsten foil and the interlayer (wettability or diffusion leading to a solid solution or the formation of intermetallics). From the example of tungsten laminates joined by brazing with (i) an eutectic silver copper brazing filler, (ii) copper, (iii) titanium, and (iv) zirconium, the microstructure will be discussed, with special focus on the interface. Based on our assumptions of the mechanism of the extraordinary ductility of tungsten foil we present three syntheses strategies and make recommendations for the synthesis of high temperature tungsten laminates.

  2. Scaling laws for radial foil bearings

    NASA Astrophysics Data System (ADS)

    Honavara Prasad, Srikanth

    The effects of fluid pressurization, structural deformation of the compliant members and heat generation in foil bearings make the design and analysis of foil bearings very complicated. The complex fluid-structural-thermal interactions in foil bearings also make modeling efforts challenging because these phenomena are governed by highly non-linear partial differential equations. Consequently, comparison of various bearing designs require detailed calculation of the flow fields (velocities, pressures), bump deflections (structural compliance) and heat transfer phenomena (viscous dissipation in the fluid, frictional heating, temperature profile etc.,) resulting in extensive computational effort (time/hardware). To obviate rigorous computations and aid in feasibility assessments of foil bearings of various sizes, NASA developed the "rule of thumb" design guidelines for estimation of journal bearing load capacity. The guidelines are based on extensive experimental data. The goal of the current work is the development of scaling laws for radial foil bearings to establish an analytical "rule of thumb" for bearing clearance and bump stiffness. The use of scale invariant Reynolds equation and experimentally observed NASA "rule of thumb" yield scale factors which can be deduced from first principles. Power-law relationships between: a. Bearing clearance and bearing radius, and b. bump stiffness and bearing radius, are obtained. The clearance and bump stiffness values obtained from scaling laws are used as inputs for Orbit simulation to study various cases. As the clearance of the bearing reaches the dimensions of the material surface roughness, asperity contact breaks the fluid film which results in wear. Similarly, as the rotor diameter increases (requiring larger bearing diameters), the load capacity of the fluid film should increase to prevent dry rubbing. This imposes limits on the size of the rotor diameter and consequently bearing diameter. Therefore, this thesis aims

  3. Target foil rupture scenario and provision for handling different models of medical cyclotrons used in India.

    PubMed

    Shaiju, V S; Sharma, S D; Kumar, Rajesh; Sarin, B

    2009-07-01

    Medical cyclotron is a particle accelerator used in producing short lived radiotracers such as (18)F, (11)C, (15)O, (13)N etc. These radiotracers are labeled with suitable pharmaceuticals for use to gather information related to metabolic activity of the cell using Positron Emission Tomography (PET) scan. Target foil rupture is considered one of the major emergency situations during medical cyclotron operations because there is a potential of over exposure to the working personnel. Radiation protection survey of a self-shielded medical cyclotron installation was carried out during normal and emergency conditions. It is found that the induced activity in the target foil increases with its successive usages. As a case study, we have evaluated the emergency handling procedures of GE PETtrace-6 medical cyclotron. Recommendations have also been made to reduce personal exposure while handling the target foil rupture condition such as the use of L-Bench near the target area and participation of experienced personnel.

  4. Nuclear target foil fabrication for the Romano Event

    SciTech Connect

    Weed, J.W.; Romo, J.G. Jr.; Griggs, G.E.

    1984-06-19

    The Vacuum Processes Lab, of LLNL's M.E. Dept. - Material Fabrication Division, was requested to provide 250 coated Parylene target foils for a nuclear physics experiment titled the ROMANO Event. Due to the developmental nature of some of the fabrication procedures, approximately 400 coated foils were produced to satisfy the event's needs. The foils were used in the experiment as subkilovolt x-ray, narrow band pass filters, and wide band ultraviolet filters. This paper is divided into three sections describing: (1) nuclear target foil fabrication, (2) Parylene substrate preparation and production, and (3) foil and substrate inspections.

  5. Studies of neutron cross-sections important for spallation experiments using the activation method

    NASA Astrophysics Data System (ADS)

    Vrzalová, J.; Chudoba, P.; Krása, A.; Majerle, M.; Suchopár, M.; Svoboda, O.; Wagner, V.

    2014-09-01

    A series of experiments devoted to studies of neutron cross-sections by activation method was carried out. The cross-sections of various threshold reactions were studied by means of different quasi-monoenergetic neutron sources with energies from 14 MeV up to 100 MeV. Threshold reactions in various materials are among other used to measure fast neutron fields produced during accelerator driven system studies. For this reason our measurements of neutron cross-sections are crucial. At present, neither experimental nor evaluated data above 30 MeV are available for neutron threshold reactions in Au, I and In published in this proceedings. We studied materials in the form of thin foils and compared our data with the calculations preformed using the deterministic code TALYS 1.4.

  6. In situ calibration of the foil detector for an infrared imaging video bolometer using a carbon evaporation technique.

    PubMed

    Mukai, K; Peterson, B J; Takayama, S; Sano, R

    2016-11-01

    The InfraRed imaging Video Bolometer (IRVB) is a useful diagnostic for the multi-dimensional measurement of plasma radiation profiles. For the application of IRVB measurement to the neutron environment in fusion plasma devices such as the Large Helical Device (LHD), in situ calibration of the thermal characteristics of the foil detector is required. Laser irradiation tests of sample foils show that the reproducibility and uniformity of the carbon coating for the foil were improved using a vacuum evaporation method. Also, the principle of the in situ calibration system was justified.

  7. Improvement of energy-conversion efficiency from laser to proton beam in a laser-foil interaction.

    PubMed

    Nodera, Y; Kawata, S; Onuma, N; Limpouch, J; Klimo, O; Kikuchi, T

    2008-10-01

    Improvement of energy-conversion efficiency from laser to proton beam is demonstrated by particle simulations in a laser-foil interaction. When an intense short-pulse laser illuminates the thin-foil target, the foil electrons are accelerated around the target by the ponderomotive force. The hot electrons generate a strong electric field, which accelerates the foil protons, and the proton beam is generated. In this paper a multihole thin-foil target is proposed in order to increase the energy-conversion efficiency from laser to protons. The multiholes transpiercing the foil target help to enhance the laser-proton energy-conversion efficiency significantly. Particle-in-cell 2.5-dimensional ( x, y, vx, vy, vz) simulations present that the total laser-proton energy-conversion efficiency becomes 9.3% for the multihole target, though the energy-conversion efficiency is 1.5% for a plain thin-foil target. The maximum proton energy is 10.0 MeV for the multihole target and is 3.14 MeV for the plain target. The transpiercing multihole target serves as a new method to increase the energy-conversion efficiency from laser to ions.

  8. Measurement of short lifetimes in highly-charged ions using a two-foil target

    SciTech Connect

    Berry, H.G.; Dunford, R.W.; Gemmell, D.S.

    1995-08-01

    One of the frontiers in the study of the atomic physics of highly-charged ions is the measurement of lifetimes in the 100 fs to 10 ps regime. The standard technique for measuring lifetimes of states in highly-charged ions is the beam-foil time-of-flight method in which the intensity of an emission line is monitored as a function of the separation between the exciting foil and the portion of the beam being viewed by the detector. This method becomes increasingly difficult as the decay lengths of the states of interest become shorter. At a typical beam velocity of 10% of the speed of light, the beam travels 30 microns in a picosecond. The standard beam-foil time-of-flight method necessitates observation of the decay radiation within one or two decay lengths from the foil while preventing the detectors from observing the beam spot at the foil. For short-lived states this requires tight collimation of the detector with a resulting loss in solid angle. We are developing a method for measuring ultrashort atomic lifetimes utilizing a two-foil target. As a specific case to demonstrate the feasibility of our method, we are studying the decay of the 2 {sup 3}P{sub 2} level in helium-like Kr{sup 34+}. This level has a calculated lifetime of 9.5 ps which corresponds to a decay length of 380 {mu}m. For krypton, theory predicts that 90% of the 2 {sup 3}P{sub 2} states decay via M2 radiation to the ground state. A measurement of the lifetime of this state would contribute to an important current problem which concerns the understanding of atomic structure when both electron correlations and relativistic effects are simultaneously important.

  9. FoilSim: Basic Aerodynamics Software Created

    NASA Technical Reports Server (NTRS)

    Peterson, Ruth A.

    1999-01-01

    FoilSim is interactive software that simulates the airflow around various shapes of airfoils. The graphical user interface, which looks more like a video game than a learning tool, captures and holds the students interest. The software is a product of NASA Lewis Research Center s Learning Technologies Project, an educational outreach initiative within the High Performance Computing and Communications Program (HPCCP).This airfoil view panel is a simulated view of a wing being tested in a wind tunnel. As students create new wing shapes by moving slider controls that change parameters, the software calculates their lift. FoilSim also displays plots of pressure or airspeed above and below the airfoil surface.

  10. VO₂/Si-Al gel nanocomposite thermochromic smart foils: largely enhanced luminous transmittance and solar modulation.

    PubMed

    Liu, C; Cao, X; Kamyshny, A; Law, J Y; Magdassi, S; Long, Y

    2014-08-01

    VO2 nanoparticles with a dimension of approximately 20 nm were obtained by simple mechanical bead-milling method, which were well dispersed in transparent silica-alumina (Si-Al) gel matrix to form nanocomposites. The VO2/Si-Al gel thermochromic nanocomposite foils were fabricated with various VO2 solid contents and foil thickness. With 10% VO2 loading and 3 μm foil thickness, high luminous transmittance (T(lum(20°C))=63.7% and T(lum(90°C))=54.4%), and large solar modulation ability (ΔTsol=12%) can be obtained which surpasses the best reported results (nanoporous films:T(lum(20°C))=43.3%, T(lum(90°C))=39.9% and ΔTsol=14.1%). This current approach provided a simple and scalable preparation method with the best combined thermochromic performance.

  11. A Novel and Generalized Lithium-Ion-Battery Configuration utilizing Al Foil as Both Anode and Current Collector for Enhanced Energy Density.

    PubMed

    Ji, Bifa; Zhang, Fan; Sheng, Maohua; Tong, Xuefeng; Tang, Yongbing

    2017-02-01

    A novel battery configuration based on an aluminum foil anode and a conventional cathode is developed. The aluminum foil plays a dual role as both the active anode material and the current collector, which enhances the energy density of the packaged battery, and reduces the production cost. This generalized battery configuration has high potential for application in next-generation lithium-ion batteries.

  12. Analysis of cartilage-polydioxanone foil composite grafts.

    PubMed

    Kim, James H; Wong, Brian

    2013-12-01

    This study presents an analytical investigation into the mechanical behavior of a cartilage-polydioxanone (PDS) plate composite grafts. Numerical methods are used to provide a first-order, numerical model of the flexural stiffness of a cartilage-PDS graft. Flexural stiffness is a measure of resistance to bending and is inversely related to the amount of deformation a structure may experience when subjected to bending forces. The cartilage-PDS graft was modeled as a single composite beam. Using Bernoulli-Euler beam theory, a closed form equation for the theoretical flexural stiffness of the composite graft was developed. A parametric analysis was performed to see how the flexural properties of the composite model changed with varying thicknesses of PDS foil. The stiffness of the cartilage-PDS composite using 0.15-mm-thick PDS was four times higher than cartilage alone. The composite with a 0.5-mm-thick PDS graft was only 1.7 times stiffer than the composite with the 0.15-mm-thick PDS graft. Although a thicker graft material will yield higher flexural stiffness for the composite, the relationship between composite stiffness and PDS thickness is nonlinear. After a critical point, increments in graft thickness produce gradually smaller improvements in flexural stiffness. The small increase in stiffness when using the thicker PDS foils versus the 0.15 mm PDS foil may not be worth the potential complications (prolonged foreign body reaction, reduction in nutrient diffusion to cartilage) of using thicker artificial grafts.

  13. Polycarbosilazane passivation on graphite foil used as gasket seal

    NASA Astrophysics Data System (ADS)

    Prette, A. L. G.; Haage, T.; Will, A.; Kolb, M.; Flores, O.; Günthner, M.; Motz, G.

    2013-12-01

    Gasket seals are often used in industry and laboratories where a leak-proof installation is needed in order to avoid loss of products or dangerous materials. Many of products transported inside tubes are at relatively high temperatures excluding polymeric gaskets. In the same line, many of transported materials contain solvents which can attack polymer sealings, therefore limiting their use. An alternative is to use graphite joints as sealings. These joints are a sandwich of graphite foil and stainless steel mesh as forming core. The problem that raises using graphite in contact with steel is that at temperatures of about 500 °C an interdiffusion of carbon on the steel structure occurs which produces adhesion of the graphite gasket on the metallic flange. Therefore this adhesion increases the time to change each gasket, since rests of previously adhered graphite has to be removed from the flange. In order to avoid the adhesion of the graphite on the flange, polycarbosilazane precursor was used as protective finishing on the graphite foil surface. After thermal transformation of the polymer into the corresponding PDC finishing, it acts in two manners: It avoids the direct contact between the carbon and the steel and it allows the sealing of liquids and gases. Adhesion tests were done and showed that the foils passivated with PDCs did not adhere to the steel flange. Moreover, the production methods and products are compatible to industrial environment and processes. The results found here show that the time to change the gasket in industry can be clearly reduced by using the PDC finishing on graphite gasket.

  14. A calorimetric method to determine water activity

    NASA Astrophysics Data System (ADS)

    Björklund, Sebastian; Wadsö, Lars

    2011-11-01

    A calorimetric method to determine water activity covering the full range of the water activity scale is presented. A dry stream of nitrogen gas is passed either over the solution whose activity should be determined or left dry before it is saturated by bubbling through water in an isothermal calorimeter. The unknown activity is in principle determined by comparing the thermal power of vaporization related to the gas stream with unknown activity to that with zero activity. Except for three minor corrections (for pressure drop, non-perfect humidification, and evaporative cooling) the unknown water activity is calculated solely based on the water activity end-points zero and unity. Thus, there is no need for calibration with references with known water activities. The method has been evaluated at 30 °C by measuring the water activity of seven aqueous sodium chloride solutions ranging from 0.1 mol kg-1 to 3 mol kg-1 and seven saturated aqueous salt solutions (LiCl, MgCl2, NaBr, NaCl, KCl, KNO3, and K2SO4) with known water activities. The performance of the method was adequate over the complete water activity scale. At high water activities the performance was excellent, which is encouraging as many other methods used for water activity determination have limited performance at high water activities.

  15. Brazing Inconel 625 Using the Copper Foil

    NASA Astrophysics Data System (ADS)

    Chen, Wen-Shiang; Wang, Cheng-Yen; Shiue, Ren-Kae

    2013-12-01

    Brazing Inconel 625 (IN-625) using the copper foil has been investigated in this research. The brazed joint is composed of nanosized CrNi3 precipitates and Cr/Mo/Nb/Ni quaternary compound in the Cu/Ni-rich matrix. The copper filler 50 μm in thickness is enough for the joint filling. However, the application of Cu foil 100 μm in thickness has little effect on the shear strength of the brazed joint. The specimen brazed at 1433 K (1160 °C) for 1800 seconds demonstrates the best shear strength of 470 MPa, and its fractograph is dominated by ductile dimple fracture with sliding marks. Decreasing the brazing temperature slightly decreases the shear strength of the brazed joint due to the presence of a few isolated solidification shrinkage voids smaller than 15 μm. Increasing the brazing temperature, especially for the specimen brazed at 1473 K (1200 °C), significantly deteriorates the shear strength of the joint below 260 MPa because of coalescence of isothermal solidification shrinkage voids in the joint. The Cu foil demonstrates potential in brazing IN-625 for industrial application.

  16. Infrared particle detection for battery electrode foils

    NASA Astrophysics Data System (ADS)

    Just, P.; Ebert, L.; Echelmeyer, T.; Roscher, M. A.

    2013-11-01

    Failures of electrochemical cells caused by internal shorts still are an important issue to be faced by the cell manufacturers and their customers. A major cause for internal shorts are contaminated electrode foils. These contaminations have to be detected securely via a non-destructive inspection technique integrated into the electrode manufacturing process. While optical detection already is state of the art, infrared detection of particles finds a new field of application in the battery electrode manufacturing process. This work presents two approaches focusing on electrode inspection by electromagnetic radiation (visible and infrared). Copper foils with a carbon based coating were intentionally contaminated by slivers of aluminum and copper as well as by abraded coating particles. Optical excitation by a flash and a luminescent lamp was applied at different angles in order to detect the reflected visible radiation. A laser impulse was used to heat up the specimen for infrared inspection. Both approaches resulted in setups providing a high contrast between contaminations and the coated electrode foil. It is shown that infrared detection offers a higher security thanks to its reliance on absorbance and emissivity instead of reflectivity as it is used for optical detection. Infrared Detection offers a potential since it is hardly influenced by the particle's shape and orientation and the electrode's waviness.

  17. Beam-Foil Spectroscopy - Quo Vadis?

    SciTech Connect

    Trabert, E

    2008-05-26

    Beam-foil spectroscopy after 45 years: what has been realized of the promises, what is the state of the art, what is the status of the field, what present atomic physics problems should the technique be applied to, where can it be done? Will it be done? Beam-foil spectroscopy and its sibling techniques have been outstandingly productive tools of atomic physics, providing both important data and insight. For some forty years, the developments have led to improvements in working range and reliability, and catalogues of desirable further measurements can be formulated. However, most of the key persons who have carried out and directed much of the development effort are nearing retirement, and with them the leading facilities. it is thus not likely that many of the desirable BFS projects discussed will presently be pursued. High-Z element, high-charge state spectroscopy and some specific long-lived level lifetime measurements will, however, be taken over by electron beam ion traps, and heavy-ion storage rings will contribute some important benchmark measurements on electric-dipole forbidden or hyperfine-induced transitions. Beam-foil spectroscopy can still be expected to solve a number of interesting atomic physics questions, but as a technique, at present, it has dropped from fashion and support.

  18. Lab-on-a-Foil: microfluidics on thin and flexible films.

    PubMed

    Focke, Maximilian; Kosse, Dominique; Müller, Claas; Reinecke, Holger; Zengerle, Roland; von Stetten, Felix

    2010-06-07

    This critical review is motivated by an increasing interest of the microfluidics community in developing complete Lab-on-a-Chip solutions based on thin and flexible films (Lab-on-a-Foil). Those implementations benefit from a broad range of fabrication methods that are partly adopted from well-established macroscale processes or are completely new and promising. In addition, thin and flexible foils enable various features like low thermal resistance for efficient thermocycling or integration of easily deformable chambers paving the way for new means of on-chip reagent storage or fluid transport. From an economical perspective, Lab-on-a-Foil systems are characterised by low material consumption and often low-cost materials which are attractive for cost-effective high-volume fabrication of self-contained disposable chips. The first part of this review focuses on available materials, fabrication processes and approaches for integration of microfluidic functions including liquid control and transport as well as storage and release of reagents. In the second part, an analysis of the state of Lab-on-a-Foil applications is provided with a special focus on nucleic acid analysis, immunoassays, cell-based assays and home care testing. We conclude that the Lab-on-a-Foil approach is very versatile and significantly expands the toolbox for the development of Lab-on-a-Chip solutions.

  19. Computational design of flapping kinematics of a flexible finite-span foil

    NASA Astrophysics Data System (ADS)

    Hong, Seungpyo; Lee, Jinmo; You, Donghyun

    2013-11-01

    While many of the effects of chordwise flexibility of a two-dimensional plate or a foil under pitching motions are revealed in recent computational and experimental research, the effects of flexibility of a three-dimensional foil on the manipulation of wing-tip vortices as well as leading-/trailing-edge vortices are rarely understood. The present study aims at identifying flow physics associated with flapping motions of flexible finite-span foils and the effects of the flapping kinematics and flexibility of the foil on the propulsive performance. The propulsive performance and fluid dynamics of wing-tip vortices leading-edge and trailing-edge vortices associated with the thrust generation are investigated in detail by conducting numerical simulations of flow over a flapping foil with different span-to-chord aspect ratios and bending stiffness using a recently developed coupled immersed boundary method and computational structural dynamics. Supported by the Office of Naval Research Grant N000141110652 and the National Research Foundation of Korea Grant NRF-2012R1A1A2003699.

  20. High fidelity studies of exploding foil initiator bridges, Part 2: Experimental results

    NASA Astrophysics Data System (ADS)

    Neal, William; Bowden, Mike

    2017-01-01

    Simulations of high voltage detonators, such as Exploding Bridgewire (EBW) and Exploding Foil Initiators (EFI), have historically been simple, often empirical, one-dimensional models capable of predicting parameters such as current, voltage, and in the case of EFIs, flyer velocity. Experimental methods have correspondingly generally been limited to the same parameters. With the advent of complex, first principles magnetohydrodynamic codes such as ALEGRA MHD, it is now possible to simulate these components in three dimensions and predict greater range of parameters than before. A significant improvement in experimental capability was therefore required to ensure these simulations could be adequately verified. In this second paper of a three part study, data is presented from a flexible foil EFI header experiment. This study has shown that there is significant bridge expansion before time of peak voltage and that heating within the bridge material is spatially affected by the microstructure of the metal foil.

  1. Nonlinear dynamics of flexible rotor supported on the gas foil journal bearings

    NASA Astrophysics Data System (ADS)

    Bhore, Skylab P.; Darpe, Ashish K.

    2013-09-01

    Investigation on nonlinear dynamics of a flexible rotor supported on the gas foil journal bearings is attempted. A time domain orbit simulation is carried out that couples the equations of rotor motion, unsteady Reynolds equation and foil deformation. The unsteady Reynolds equation is solved using control volume formulation with power law hybrid scheme and Gauss-Seidel method. The nonlinear dynamic response is analyzed using disc center and journal center trajectories, Poincaré maps, Fast Fourier transforms and bifurcation plots. The analysis is carried out for different system parameters, namely, rotating speed, unbalance eccentricity, compliance and loss factor of gas foil bearing. The analysis reveals highly nonlinear behavior with periodic, multi-periodic and quasiperiodic motion of the disc and the journal center. The present analysis can be useful in designing and selection of suitable operating parameters of rotor bearing system.

  2. The Effect of Journal Roughness and Foil Coatings on the Performance of Heavily Loaded Foil Air Bearings

    NASA Technical Reports Server (NTRS)

    Radil, Kevin C.; DellaCorte, Christopher

    2001-01-01

    Foil air bearing load capacity tests were conducted to investigate if a solid lubricant coating applied to the surface of the bearing's top foil can function as a break-in coating. Two foil coating materials, a conventional soft polymer film (polyimide) and a hard ceramic (alumina), were independently evaluated against as-ground and worn (run-in) journals coated with NASA PS304, a high-temperature solid lubricant composite coating. The foil coatings were evaluated at journal rotational speeds of 30,000 rpm and at 25 C. Tests were also performed on a foil bearing with a bare (uncoated) nickel-based superalloy top foil to establish a baseline for comparison. The test results indicate that the presence of a top foil solid lubricant coating is effective at increasing the load capacity performance of the foil bearing. Compared to the uncoated baseline, the addition of the soft polymer coating on the top foil increased the bearing load coefficient by 120% when operating against an as-ground journal surface and 85 percent against a run-in journal surface. The alumina coating increased the load coefficient by 40% against the as-ground journal but did not have any affect when the bearing was operated with the run-in journal. The results suggest that the addition of solid lubricant films provide added lubrication when the air film is marginal indicating that as the load capacity is approached foil air bearings transition from hydrodynamic to mixed and boundary lubrication.

  3. Fission fragment assisted reactor concept for space propulsion: Foil reactor

    NASA Technical Reports Server (NTRS)

    Wright, Steven A.

    1991-01-01

    The concept is to fabricate a reactor using thin films or foils of uranium, uranium oxide and then to coat them on substrates. These coatings would be made so thin as to allow the escaping fission fragments to directly heat a hydrogen propellant. The idea was studied of direct gas heating and direct gas pumping in a nuclear pumped laser program. Fission fragments were used to pump lasers. In this concept two substrates are placed opposite each other. The internal faces are coated with thin foil of uranium oxide. A few of the advantages of this technology are listed. In general, however, it is felt that if one look at all solid core nuclear thermal rockets or nuclear thermal propulsion methods, one is going to find that they all pretty much look the same. It is felt that this reactor has higher potential reliability. It has low structural operating temperatures, very short burn times, with graceful failure modes, and it has reduced potential for energetic accidents. Going to a design like this would take the NTP community part way to some of the very advanced engine designs, such as the gas core reactor, but with reduced risk because of the much lower temperatures.

  4. Extreme extensibility of copper foil under compound forming conditions.

    PubMed

    Yu, Qingbo; Liu, Xianghua; Tang, Delin

    2013-12-19

    A copper foil with an extreme extensibility up to 43,684% was obtained without any intermediate annealing by means of asynchronous rolling with high tension. It was found that under the combination of compression, shearing and tension, the copper foil represents a wonderful phenomenon. As the reduction increases, the specimen hardness increases up to a peak value 138 HV0.05 when the foil thickness rolled to around 100 μm, and then it decreases down to 78 HV0.05 when the foil thickness rolled to the final size 19 μm. It tells us that the strain-softening effect occurs when the foil thickness is rolled down to a threshold level. The experimental results bring us some fresh ideas different with the traditional understanding on the strain-hardening mechanism of metals, which provides an experimental basis to establish the forming mechanism of the thin foil.

  5. Microfabricated Segmented-Involute-Foil Regenerator for Stirling Engines

    NASA Technical Reports Server (NTRS)

    Ibrahim, Mounir; Danila, Daniel; Simon, Terrence; Mantell, Susan; Sun, Liyong; Gedeon, David; Qiu, Songgang; Wood, Gary; Kelly, Kevin; McLean, Jeffrey

    2010-01-01

    An involute-foil regenerator was designed, microfabricated, and tested in an oscillating-flow test rig. The concept consists of stacked involute-foil nickel disks (see figure) microfabricated via a lithographic process. Test results yielded a performance of about twice that of the 90-percent random-fiber currently used in small Stirling converters. The segmented nature of the involute- foil in both the axial and radial directions increases the strength of the structure relative to wrapped foils. In addition, relative to random-fiber regenerators, the involute-foil has a reduced pressure drop, and is expected to be less susceptible to the release of metal fragments into the working space, thus increasing reliability. The prototype nickel involute-foil regenerator was adequate for testing in an engine with a 650 C hot-end temperature. This is lower than that required by larger engines, and high-temperature alloys are not suited for the lithographic microfabrication approach.

  6. SEM-EDS Analyses of Small Craters in Stardust Aluminum Foils: Implications for the Wild-2 Dust Distribution

    NASA Technical Reports Server (NTRS)

    Borg, J.; Horz, F.; Bridges, J. C.; Burchell, M. J.; Djouadi, Z.; Floss, C.; Graham, G. A.; Green, S. F.; Heck, P. R.; Hoppe, P.; Huth, J.; Kearsley, A; Leroux, H.; Marhas, K.; Stadermann, F. J.; Teslich, N.

    2007-01-01

    Aluminium foils were used on Stardust to stabilize the aerogel specimens in the modular collector tray. Part of these foils were fully exposed to the flux of cometary grains emanating from Wild 2. Because the exposed part of these foils had to be harvested before extraction of the aerogel, numerous foil strips some 1.7 mm wide and 13 or 33 mm long were generated during Stardusts's Preliminary Examination (PE). These strips are readily accommodated in their entirety in the sample chambers of modern SEMs, thus providing the opportunity to characterize in situ the size distribution and residue composition - employing EDS methods - of statistically more significant numbers of cometary dust particles compared to aerogel, the latter mandating extensive sample preparation. We describe here the analysis of nearly 300 impact craters and their implications for Wild 2 dust.

  7. Recalibration of indium foil for personnel screening in criticality accidents.

    PubMed

    Takada, C; Tsujimura, N; Mikami, S

    2011-03-01

    At the Nuclear Fuel Cycle Engineering Laboratories of the Japan Atomic Energy Agency (JAEA), small pieces of indium foil incorporated into personal dosemeters have been used for personnel screening in criticality accidents. Irradiation tests of the badges were performed using the SILENE reactor to verify the calibration of the indium activation that had been made in the 1980s and to recalibrate them for simulated criticalities that would be the most likely to occur in the solution process line. In addition, Monte Carlo calculations of the indium activation using the badge model were also made to complement the spectral dependence. The results lead to a screening level of 15 kcpm being determined that corresponds to a total dose of 0.25 Gy, which is also applicable in posterior-anterior exposure. The recalibration based on the latest study will provide a sounder basis for the screening procedure in the event of a criticality accident.

  8. Developing NanoFoil-Heated Thin-Film Thermal Battery

    DTIC Science & Technology

    2013-09-01

    NanoFoil-Heated Thin- Film Thermal Battery ..........................................6 3. Results and Discussion 8 3.1 Regulation of Skin ...Developing NanoFoil-Heated Thin- Film Thermal Battery by Michael S. Ding, Frank C. Krieger, and Jeffrey A. Swank ARL-TR-6664 September...TR-6664 September 2013 Developing NanoFoil-Heated Thin- Film Thermal Battery Michael S. Ding, Frank C. Krieger, and Jeffrey A. Swank

  9. Pulsed Electric Discharge Laser Technology. Electron Beam Window Foil Material.

    DTIC Science & Technology

    1984-01-01

    6.0 INTERFEROMETRIC MEASUREMENT OF FOIL MOVEMENT A simple Michelson interferometer was used to measure foil movement on the test rig. Because the...TURNING BEAM MIRRORS BEAM DISPLAYFOCUEED IRIS AT FOOS. OPTICAL FIBRE * BUNDLE Figure 49. Schematic of interferometer . -98-7 reflected speckle. The...As a check on the pulse simulation, the actual movement of an electron-beam foil window was measured by interferometry. A speckle interferometer which

  10. Optical temperature sensing on flexible polymer foils

    NASA Astrophysics Data System (ADS)

    Sherman, Stanislav; Xiao, Yanfen; Hofmann, Meike; Schmidt, Thomas; Gleissner, Uwe; Zappe, Hans

    2016-04-01

    In contrast to established semiconductor waveguide-based or glass fiber-based integrated optical sensors, polymerbased optical systems offer tunable material properties, such as refractive index or viscosity, and thus provide additional degrees of freedom for sensor design and fabrication. Of particular interest in sensing applications are fully-integrated optical waveguide-based temperature sensors. These typically rely on Bragg gratings which induce a periodic refractive index variation in the waveguide so that a resonant wavelength of the structure is reflected.1,2 With broad-band excitation, a dip in the spectral output of the waveguide is thus generated at a precisely-defined wavelength. This resonant wavelength depends on the refractive index of the waveguide and the grating period, yet both of these quantities are temperature dependent by means of the thermo-optic effect (change in refractive index with temperature) and thermal expansion (change of the grating period with temperature). We show the design and fabrication of polymer waveguide-integrated temperature sensors based on Bragggratings, fabricated by replication technology on flexible PMMA foil substrates. The 175 μm thick foil serves as lower cladding for a polymeric waveguide fabricated from a custom-made UV-crosslinkable co-monomer composition. The fabrication of the grating structure includes a second replication step into a separate PMMA-foil. The dimensions of the Bragg-gratings are determined by simulations to set the bias point into the near infrared wavelength range, which allows Si-based detectors to be used. We present design considerations and performance data for the developed structures. The resulting sensor's signal is linear to temperature changes and shows a sensitivity of -306 nm/K, allowing high resolution temperature measurements.

  11. Radiation pressure acceleration of ultrathin foils

    NASA Astrophysics Data System (ADS)

    Macchi, Andrea; Veghini, Silvia; Liseykina, Tatyana V.; Pegoraro, Francesco

    2010-04-01

    The acceleration of sub-wavelength, solid-density plasma foils by the ultraintense radiation pressure of circularly polarized laser pulses is investigated analytically and with simulations. An improved 'Light Sail' or accelerating mirror model, accounting for nonlinear self-induced transparency effects, is used for estimating the optimal thickness for acceleration. The model predictions are in good agreement with one-dimensional simulations. These latter are analyzed in detail to unfold the dynamics and self-organization of electrons and ions during the acceleration. Two-dimensional simulations are also performed to address the effects of target bending and of laser intensity inhomogeneity.

  12. Note: the influence of exploding foil shape on energy deposition.

    PubMed

    Zeng, Qingxuan; Lv, Junjun; Li, Mingyu

    2013-06-01

    The main influence factors of exploding bridge foil were studied in order to improve energy utilization of the explosion foil initiator. "Square" and "curving" shaped bridge foils were fabricated using magnetron sputtering and chemical etching techniques, and the key dimension of the bridge foil was measured using surface profiler. Commercial software MATLAB was employed to calculate the burst current, burst voltage, and energy deposition. Simulation results were in good agreement with experiment data. In this study, the energy deposition ratio of "square" shaped bridge is between 45%-50%, while the value of "curving" shaped bridge is between 55%-75%.

  13. Characterization of U-Mo Foils for AFIP-7

    SciTech Connect

    Edwards, Danny J.; Ermi, Ruby M.; Schemer-Kohrn, Alan L.; Overman, Nicole R.; Henager, Charles H.; Burkes, Douglas; Senor, David J.

    2012-11-07

    Twelve AFIP in-process foil samples, fabricated by either Y-12 or LANL, were shipped from LANL to PNNL for potential characterization using optical and scanning electron microscopy techniques. Of these twelve, nine different conditions were examined to one degree or another using both techniques. For this report a complete description of the results are provided for one archive foil from each source of material, and one unirradiated piece of a foil of each source that was irradiated in the Advanced Test Reactor. Additional data from two other LANL conditions are summarized in very brief form in an appendix. The characterization revealed that all four characterized conditions contained a cold worked microstructure to different degrees. The Y-12 foils exhibited a higher degree of cold working compared to the LANL foils, as evidenced by the highly elongated and obscure U-Mo grain structure present in each foil. The longitudinal orientations for both of the Y-12 foils possesses a highly laminar appearance with such a distorted grain structure that it was very difficult to even offer a range of grain sizes. The U-Mo grain structure of the LANL foils, by comparison, consisted of a more easily discernible grain structure with a mix of equiaxed and elongated grains. Both materials have an inhomogenous grain structure in that all of the characterized foils possess abnormally coarse grains.

  14. SNS STRIPPER FOIL FAILURE MODES AND THEIR CURES

    SciTech Connect

    Galambos, John D; Luck, Chris; Plum, Michael A; Shaw, Robert W; Ladd, Peter; Raparia, Deepak; Macek, Robert James; Kim, Sang-Ho; Peters, Charles C; Polsky, Yarom

    2010-01-01

    The diamond stripper foils in use at the Spallation Neutron Source worked successfully with no failures until May 3, 2009, when we started experiencing a rash of foil system failures after increasing the beam power to ~840 kW. The main contributors to the failures are thought to be 1) convoy electrons, stripped from the incoming H beam, that strike the foil bracket and may also reflect back from the electron catcher, and 2) vacuum breakdown from the charge developed on the foil by secondary electron emission. In this paper we will detail these and other failure mechanisms, and describe the improvements we have made to mitigate them.

  15. Apparatus and process for ultrasonic seam welding stainless steel foils

    DOEpatents

    Leigh, Richard W.

    1992-01-01

    An ultrasonic seam welding apparatus having a head which is rotated to form contact, preferably rolling contact, between a metallurgically inert coated surface of the head and an outside foil of a plurality of layered foils or work materials. The head is vibrated at an ultrasonic frequency, preferably along a longitudinal axis of the head. The head is constructed to transmit vibration through a contacting surface of the head into each of the layered foils. The contacting surface of the head is preferably coated with aluminum oxide to prevent the head from becoming welded to layered stainless steel foils.

  16. Ti foil light in the ATA (Advanced Test Accelerator) beam

    SciTech Connect

    Slaughter, D.R.; Chong, Y.P.; Goosman, D.R.; Rule, D.W.; Fiorito, R.B.

    1987-09-01

    An experiment is in progress to characterize the visible light produced when a Ti foil is immersed in the ATA 2 kA, 43 MeV beam. Results obtained to date indicate that the optical condition of the foil surface is a critical determinant of these characteristics, with a very narrow angular distribution obtained when a highly polished and flat foil is used. These data are consistent with the present hypothesis that the light is produced by transition radiation. Incomplete experiments to determine the foil angle dependence of the detected light and its polarization are summarized and remaining experiments are described.

  17. Synthesis of nano ZnO thin film on Al foil by rf glow discharge plasma and its effect on E. coli and P. aeruginosa

    NASA Astrophysics Data System (ADS)

    Panigrahi, Jagannath; Nayak, Bijan B.; Behera, Debadhyan; Subudhi, Umakanta; Acharya, Bhabani S.

    2012-09-01

    Nano ZnO thin films were deposited on thin Al foils by a rf glow discharge plasma method in which sublimed zinc acetate vapor (precursor) reacted with oxygen plasma inside a low-pressure reactor. The films were microstructurally characterized using XRD, TEM, FESEM, optical reflectance and micro-Raman spectroscopy methods. In view of the good scope of ZnO coating in food packaging, the antibacterial activity in the ZnO thin films was studied by exposing the films to E. coli and P. aeruginosa for up to 8 h. Bacterial cell inhibition of up to 98-99 % was observed in the thin films.

  18. METHOD OF SUPPRESSING GASTROINTESTINAL UREASE ACTIVITY

    DOEpatents

    Visek, W.J.

    1963-04-23

    This patent shows a method of increasing the growth rate of chicks. Certain diacyl substituted ureas such as alloxan, murexide, and barbituric acid are added to their feed, thereby suppressing gastrointestinal urease activity and thus promoting growth. (AEC)

  19. Encapsulation method for maintaining biodecontamination activity

    DOEpatents

    Rogers, Robert D.; Hamilton, Melinda A.; Nelson, Lee O.; Benson, Jennifer; Green, Martin J.; Milner, Timothy N.

    2006-04-11

    A method for maintaining the viability and subsequent activity of microorganisms utilized in a variety of environments to promote biodecontamination of surfaces. One application involves the decontamination of concrete surfaces. Encapsulation of microbial influenced degradation (MID) microorganisms has shown that MID activity is effectively maintained under passive conditions, that is, without manual addition of moisture or nutrients, for an extended period of time.

  20. Encapsulation method for maintaining biodecontamination activity

    DOEpatents

    Rogers, Robert D.; Hamilton, Melinda A.; Nelson, Lee O.; Benson, Jennifer; Green, Martin J.; Milner, Timothy N.

    2002-01-01

    A method for maintaining the viability and subsequent activity of microorganisms utilized in a variety of environments to promote biodecontamination of surfaces. One application involves the decontamination of concrete surfaces. Encapsulation of microbial influenced degradation (MID) microorganisms has shown that MID activity is effectively maintained under passive conditions, that is, without manual addition of moisture or nutrients, for an extended period of time.

  1. Visualization of terahertz surface waves propagation on metal foils

    PubMed Central

    Wang, Xinke; Wang, Sen; Sun, Wenfeng; Feng, Shengfei; Han, Peng; Yan, Haitao; Ye, Jiasheng; Zhang, Yan

    2016-01-01

    Exploitation of surface plasmonic devices (SPDs) in the terahertz (THz) band is always beneficial for broadening the application potential of THz technologies. To clarify features of SPDs, a practical characterization means is essential for accurately observing the complex field distribution of a THz surface wave (TSW). Here, a THz digital holographic imaging system is employed to coherently exhibit temporal variations and spectral properties of TSWs activated by a rectangular or semicircular slit structure on metal foils. Advantages of the imaging system are comprehensively elucidated, including the exclusive measurement of TSWs and fall-off of the time consumption. Numerical simulations of experimental procedures further verify the imaging measurement accuracy. It can be anticipated that this imaging system will provide a versatile tool for analyzing the performance and principle of SPDs. PMID:26729652

  2. Insulating effectiveness of self-spacing dimpled foil

    NASA Technical Reports Server (NTRS)

    Bond, J. A.

    1972-01-01

    Experimental data are graphed for determining conductive heat losses of multilayer insulation as function of number of foil layers. Foil was 0.0051 cm thick Nb, 1% Zr refractory alloy, dimpled to 0.0254 cm with approximately 28 dimples/sq cm. Heat losses were determined at 0.1 microtorr between 700 and 1089 K.

  3. Foil optimization for low energy neutral atom imaging

    SciTech Connect

    Funsten, H.O.; McComas, D.J.; Barraclough, B.L.

    1992-01-01

    Magnetospheric imaging has been proposed using remote detection of low energy neutral atoms (LENAs) of magnetospheric origin. In the detector, LENAs can be removed from the immense ambient EUV by charge modification (ionization) using a carbon stripping foil and can be subsequently deflected into an E/q analysis section. The detector sensitivity efficiency of LENAs is highly dependent on the ionization probability of neutrals as they transit the carbon foil. In this study, we present equilibrium charge state distributions and scatter distributions for 1-30 keV atomic hydrogen and oxygen transiting 0.5 {mu}g cm{sup {minus}2} carbon foils. The fraction of hydrogen exiting a foil as H{sup +} ranges from approximately 5% at 1 keV to 41% at 30 keV. The fraction of oxygen exiting the foil as O{sup +} ranges from 2% at 10 keV to 8% at 30 keV. Results obtained after coating the exit surface of foils with either aluminum (which forms aluminum oxide when exposed to air) or gold suggests that the exit surface chemistry has no effect on the charge state distributions due to foil contamination from exposure to air. Scattering resulting from the atom-foil interaction is shown to be independent of the charge state distribution, suggesting that the interaction mechanisms resulting in charge exchange and scattering are distinctly different.

  4. Characterization of laser-cut copper foil X-pinches

    NASA Astrophysics Data System (ADS)

    Collins, G. W.; Valenzuela, J. C.; Hansen, S. B.; Wei, M. S.; Reed, C. T.; Forsman, A. C.; Beg, F. N.

    2016-10-01

    Quantitative data analyses of laser-cut Cu foil X-pinch experiments on the 150 ns quarter-period, ˜250 kA GenASIS driver are presented. Three different foil designs are tested to determine the effects of initial structure on pinch outcome. Foil X-pinch data are also presented alongside the results from wire X-pinches with comparable mass. The X-ray flux and temporal profile of the emission from foil X-pinches differed significantly from that of wire X-pinches, with all emission from the foil X-pinches confined to a ˜3 ns period as opposed to the delayed, long-lasting electron beam emission common in wire X-pinches. Spectroscopic data show K-shell as well as significant L-shell emission from both foil and wire X-pinches. Fits to synthetic spectra using the SCRAM code suggest that pinching foil X's produced a ˜1 keV, ne ≥ 1023 cm-3 plasma. The spectral data combined with the improved reliability of the source timing, flux, and location indicate that foil X-pinches generate a reproducible, K-shell point-projection radiography source that can be easily modified and tailored to suit backlighting needs across a variety of applications.

  5. Surface enhanced Raman scattering of gold nanoparticles supported on copper foil with graphene as a nanometer gap.

    PubMed

    Xiang, Quan; Zhu, Xupeng; Chen, Yiqin; Duan, Huigao

    2016-02-19

    Gaps with single-nanometer dimensions (<10 nm) between metallic nanostructures enable giant local field enhancements for surface enhanced Raman scattering (SERS). Monolayer graphene is an ideal candidate to obtain a sub-nanometer gap between plasmonic nanostructures. In this work, we demonstrate a simple method to achieve a sub-nanometer gap by dewetting a gold film supported on monolayer graphene grown on copper foil. The Cu foil can serve as a low-loss plasmonically active metallic film that supports the imaginary charge oscillations, while the graphene can not only create a stable sub-nanometer gap for massive plasmonic field enhancements but also serve as a chemical enhancer. We obtained higher SERS enhancements in this graphene-gapped configuration compared to those in Au nanoparticles on Cu film or on graphene-SiO2-Si. Also, the Raman signals measured maintained their fine features and intensities over a long time period, indicating the stability of this Au-graphene-Cu hybrid configuration as an SERS substrate.

  6. On-line measurements of proton beam current from a PET cyclotron using a thin aluminum foil

    NASA Astrophysics Data System (ADS)

    Ghithan, S.; do Carmo, S. J. C.; Ferreira Marques, R.; Fraga, F. A. F.; Simões, H.; Alves, F.; Crespo, P.

    2013-07-01

    The number of cyclotrons capable of accelerating protons to about 20 MeV is increasing throughout the world. Originally aiming at the production of positron emission tomography (PET) radionuclides, some of these facilities are equipped with several beam lines suitable for scientific research. Radiobiology, radiophysiology, and other dosimetric studies can be performed using these beam lines. In this work, we measured the Bragg peak of the protons from a PET cyclotron using a stacked target consisting of several aluminum foils interleaved with polyethylene sheets, readout by in-house made transimpedance electronics. The measured Bragg peak is consistent with simulations performed using the SRIM/TRIM simulation toolkit. Furthermore, we report on experimental results aiming at measuring proton beam currents down to 10 pA using a thin aluminum foil (20-μm-thick). The aluminum was chosen for this task because it is radiation hard, it has low density and low radiation activity, and finally because it is easily available at negligible cost. This method allows for calculating the dose delivered to a target during an irradiation with high efficiency, and with minimal proton energy loss and scattering.

  7. Oxidation-assisted graphene heteroepitaxy on copper foil.

    PubMed

    Reckinger, Nicolas; Tang, Xiaohui; Joucken, Frédéric; Lajaunie, Luc; Arenal, Raul; Dubois, Emmanuel; Hackens, Benoît; Henrard, Luc; Colomer, Jean-François

    2016-11-10

    We propose an innovative, easy-to-implement approach to synthesize aligned large-area single-crystalline graphene flakes by chemical vapor deposition on copper foil. This method doubly takes advantage of residual oxygen present in the gas phase. First, by slightly oxidizing the copper surface, we induce grain boundary pinning in copper and, in consequence, the freezing of the thermal recrystallization process. Subsequent reduction of copper under hydrogen suddenly unlocks the delayed reconstruction, favoring the growth of centimeter-sized copper (111) grains through the mechanism of abnormal grain growth. Second, the oxidation of the copper surface also drastically reduces the nucleation density of graphene. This oxidation/reduction sequence leads to the synthesis of aligned millimeter-sized monolayer graphene domains in epitaxial registry with copper (111). The as-grown graphene flakes are demonstrated to be both single-crystalline and of high quality.

  8. Multilayer roll bonded aluminium foil: processing, microstructure and flow stress

    SciTech Connect

    Barlow, C.Y.; Nielsen, P.; Hansen, N

    2004-08-02

    Bulk aluminium has been produced by warm-rolling followed by cold-rolling of commercial purity (99% purity) aluminium foil. The bonding appeared perfect from observation with the naked eye, light and transmission electron microscopy. By comparison with bulk aluminium of similar purity (AA1200) rolled to a similar strain (90%RA), the roll-bonded metal showed a much higher density of high-angle grain boundaries, similar strength and improved thermal stability. This study has implications for a number of applications in relation to the processing of aluminium. Roll bonding is of interest as a method for grain size refinement; oxide-containing materials have increased strength, enhanced work-hardening behaviour, and exhibit alterations in recrystallisation behaviour. The behaviour of the hard oxide film is of interest in aluminium processing, and has been investigated by characterising the size and distribution of oxide particles in the roll-bonded samples.

  9. Gas Foil Bearing Misalignment and Unbalance Effects

    NASA Technical Reports Server (NTRS)

    Howard, Samuel A.

    2008-01-01

    The effects of misalignment and unbalance on gas foil bearings are presented. The future of U.S. space exploration includes plans to conduct science missions aboard space vehicles, return humans to the Moon, and place humans on Mars. All of these endeavors are of long duration, and require high amounts of electrical power for propulsion, life support, mission operations, etc. One potential source of electrical power of sufficient magnitude and duration is a nuclear-fission-based system. The system architecture would consist of a nuclear reactor heat source with the resulting thermal energy converted to electrical energy through a dynamic power conversion and heat rejection system. Various types of power conversion systems can be utilized, but the Closed Brayton Cycle (CBC) turboalternator is one of the leading candidates. In the CBC, an inert gas heated by the reactor drives a turboalternator, rejects excess heat to space through a heat exchanger, and returns to the reactor in a closed loop configuration. The use of the CBC for space power and propulsion is described in more detail in the literature (Mason, 2003). In the CBC system just described, the process fluid is a high pressure inert gas such as argon, krypton, or a helium-xenon mixture. Due to the closed loop nature of the system and the associated potential for damage to components in the system, contamination of the working fluid is intolerable. Since a potential source of contamination is the lubricant used in conventional turbomachinery bearings, Gas Foil Bearings (GFB) have high potential for the rotor support system. GFBs are compliant, hydrodynamic journal and thrust bearings that use a gas, such as the CBC working fluid, as their lubricant. Thus, GFBs eliminate the possibility of contamination due to lubricant leaks into the closed loop system. Gas foil bearings are currently used in many commercial applications, both terrestrial and aerospace. Aircraft Air Cycle Machines (ACMs) and ground

  10. Visible light photoinactivation of bacteria by tungsten oxide nanostructures formed on a tungsten foil

    NASA Astrophysics Data System (ADS)

    Ghasempour, Fariba; Azimirad, Rouhollah; Amini, Abbas; Akhavan, Omid

    2015-05-01

    Antibacterial activity of tungsten oxide nanorods/microrods were studied against Escherichia coli bacteria under visible light irradiation and in dark. A two-step annealing process at temperatures up to 390 °C and 400-800 °C was applied to synthesize the tungsten oxide nanorods/microrods on tungsten foils using KOH as a catalyst. Annealing the foils at 400 °C in the presence of catalyst resulted in formation of tungsten oxide nanorods (with diameters of 50-90 nm and crystalline phase of WO3) on surface of tungsten foils. By increasing the annealing temperature up to 800 °C, tungsten oxide microrods with K2W6O19 crystalline phase were formed on the foils. The WO3 nanorods showed a strong antibacterial property under visible light irradiation, corresponding to >92% bacterial inactivation within 24 h irradiation at room temperature, while the K2W6O19 microrods formed at 800 °C could inactivate only ∼45% of the bacteria at the same conditions.

  11. Slumped glass foils as substrate for adjustable x-ray optics

    NASA Astrophysics Data System (ADS)

    Salmaso, Bianca; Basso, Stefano; Civitani, Marta; Ghigo, Mauro; Hołyszko, Joanna; Pelliciari, Carlo; Spiga, Daniele; Vecchi, Gabriele; Pareschi, Giovanni

    2016-09-01

    Thin glass modular mirrors are a viable solution to build future X-ray telescopes with high angular resolution and large collecting area. In our laboratories, we shape thin glass foils by hot slumping and we apply pressure to assist the replication of a cylindrical mould figure; this technology is coupled with an integration process able to damp low frequency errors and produces optics in the Wolter I configuration, typical for the X-ray telescopes. From the point of view of the hot slumping process, the efforts were focused in reducing low-, mid- and high- frequency errors of the formed Eagle glass foils. Some of our slumped glass foils were used for the development of active X-ray optics, where piezoelectric actuators are used to correct the slumped glass foil deviations from the ideal shape. In particular, they were used for the Adjustable X-raY optics for astrOnoMy project (AXYOM) developed in Italy, and the X-ray Surveyor mission, as developed at the Smithsonian Astrophysical Observatory / Center for Astrophysics (SAO/CfA) in USA. In this paper we describe the optimisation of the hot slumping process, comparing the results with the requirements of the considered active optics projects. Finally, since the present configuration of the Pennsylvania State University (PSU) coating equipment is limited to 100 x 100 mm2, the slumped glass foils used for the SAO project were cut from 200 x 200 mm2 to 100 x 100 mm2, and a low-frequency change was observed. A characterisation of the profile change upon cutting is presented.

  12. High strain rate metalworking with vaporizing foil actuator: control of flyer velocity by varying input energy and foil thickness.

    PubMed

    Vivek, A; Hansen, S R; Daehn, Glenn S

    2014-07-01

    Electrically driven rapid vaporization of thin metallic foils can generate a high pressure which can be used to launch flyers at high velocities. Recently, vaporizing foil actuators have been applied toward a variety of impulse-based metal working operations. In order to exercise control over this useful tool, it is imperative that an understanding of the effect of characteristics of the foil actuator on its ability for mechanical impulse generation is developed. Here, foil actuators made out of 0.0508 mm, 0.0762 mm, and 0.127 mm thick AA1145 were used for launching AA2024-T3 sheets of thickness 0.508 mm toward a photonic Doppler velocimeter probe. Launch velocities ranging between 300 m/s and 1100 m/s were observed. In situ measurement of velocity, current, and voltage assisted in understanding the effect of burst current density and deposited electrical energy on average pressure and velocity with foil actuators of various thicknesses. For the pulse generator, geometry, and flyer used here, the 0.0762 mm thick foil was found to be optimal for launching flyers to high velocities over short distances. Experimenting with annealed foil actuators resulted in no change in the temporal evolution of flyer velocity as compared to foil actuators of full hard temper. A physics-based analytical model was developed and found to have reasonable agreement with experiment.

  13. High strain rate metalworking with vaporizing foil actuator: Control of flyer velocity by varying input energy and foil thickness

    NASA Astrophysics Data System (ADS)

    Vivek, A.; Hansen, S. R.; Daehn, Glenn S.

    2014-07-01

    Electrically driven rapid vaporization of thin metallic foils can generate a high pressure which can be used to launch flyers at high velocities. Recently, vaporizing foil actuators have been applied toward a variety of impulse-based metal working operations. In order to exercise control over this useful tool, it is imperative that an understanding of the effect of characteristics of the foil actuator on its ability for mechanical impulse generation is developed. Here, foil actuators made out of 0.0508 mm, 0.0762 mm, and 0.127 mm thick AA1145 were used for launching AA2024-T3 sheets of thickness 0.508 mm toward a photonic Doppler velocimeter probe. Launch velocities ranging between 300 m/s and 1100 m/s were observed. In situ measurement of velocity, current, and voltage assisted in understanding the effect of burst current density and deposited electrical energy on average pressure and velocity with foil actuators of various thicknesses. For the pulse generator, geometry, and flyer used here, the 0.0762 mm thick foil was found to be optimal for launching flyers to high velocities over short distances. Experimenting with annealed foil actuators resulted in no change in the temporal evolution of flyer velocity as compared to foil actuators of full hard temper. A physics-based analytical model was developed and found to have reasonable agreement with experiment.

  14. High strain rate metalworking with vaporizing foil actuator: Control of flyer velocity by varying input energy and foil thickness

    SciTech Connect

    Vivek, A. Hansen, S. R.; Daehn, Glenn S.

    2014-07-15

    Electrically driven rapid vaporization of thin metallic foils can generate a high pressure which can be used to launch flyers at high velocities. Recently, vaporizing foil actuators have been applied toward a variety of impulse-based metal working operations. In order to exercise control over this useful tool, it is imperative that an understanding of the effect of characteristics of the foil actuator on its ability for mechanical impulse generation is developed. Here, foil actuators made out of 0.0508 mm, 0.0762 mm, and 0.127 mm thick AA1145 were used for launching AA2024-T3 sheets of thickness 0.508 mm toward a photonic Doppler velocimeter probe. Launch velocities ranging between 300 m/s and 1100 m/s were observed. In situ measurement of velocity, current, and voltage assisted in understanding the effect of burst current density and deposited electrical energy on average pressure and velocity with foil actuators of various thicknesses. For the pulse generator, geometry, and flyer used here, the 0.0762 mm thick foil was found to be optimal for launching flyers to high velocities over short distances. Experimenting with annealed foil actuators resulted in no change in the temporal evolution of flyer velocity as compared to foil actuators of full hard temper. A physics-based analytical model was developed and found to have reasonable agreement with experiment.

  15. Flow over a traveling wavy foil with a passively flapping flat plate.

    PubMed

    Liu, Nansheng; Peng, Yan; Liang, Youwen; Lu, Xiyun

    2012-05-01

    Flow over a traveling wavy foil with a passively flapping flat plate has been investigated using a multiblock lattice Boltzmann equation and the immersed boundary method. The foil undergoes prescribed undulations in the lateral direction and the rigid flat plate has passive motion determined by the fluid structure interaction. This simplified model is used to study the effect of the fish caudal fin and its flexibility on the locomotion of swimming animals. The flexibility of the caudal fin is modeled by a torsion spring acting about the pivot at the conjuncture of the wavy foil and the flat plate. The study reveals that the passively oscillating flat plate contributes half of the propulsive force. The flexibility, represented by the nondimensional natural frequency F, plays a very important role in the movement and propulsive force generation of the whole body. When the plate is too flexible, the drag force is observed. As the flat plate becomes more rigid, the propulsive force that is generated when the undulation is confined to last part of the wavy foil becomes larger. The steady movement occurs at F=5. These results are consistent with the observations of some swimming animals in nature.

  16. Flow over a traveling wavy foil with a passively flapping flat plate

    NASA Astrophysics Data System (ADS)

    Liu, Nansheng; Peng, Yan; Liang, Youwen; Lu, Xiyun

    2012-05-01

    Flow over a traveling wavy foil with a passively flapping flat plate has been investigated using a multiblock lattice Boltzmann equation and the immersed boundary method. The foil undergoes prescribed undulations in the lateral direction and the rigid flat plate has passive motion determined by the fluid structure interaction. This simplified model is used to study the effect of the fish caudal fin and its flexibility on the locomotion of swimming animals. The flexibility of the caudal fin is modeled by a torsion spring acting about the pivot at the conjuncture of the wavy foil and the flat plate. The study reveals that the passively oscillating flat plate contributes half of the propulsive force. The flexibility, represented by the nondimensional natural frequency F, plays a very important role in the movement and propulsive force generation of the whole body. When the plate is too flexible, the drag force is observed. As the flat plate becomes more rigid, the propulsive force that is generated when the undulation is confined to last part of the wavy foil becomes larger. The steady movement occurs at F=5. These results are consistent with the observations of some swimming animals in nature.

  17. Adhesive force assisted imprinting of soft solid polymer films by flexible foils.

    PubMed

    Mukherjee, Rabibrata; Sharma, Ashutosh; Gonuguntla, Manoj; Patil, Ganesh K

    2008-07-01

    We report a simple, rapid, room temperature, pressure-less and large area (approximately cm2) imprinting technique for high fidelity patterning of soft solid polymer films and surfaces like cross-linked polydimethylsiloxane (PDMS) and polyacrylamide (PAA) based hydrogels, both on planar and curved surfaces. The key element of the method is the use of patterned thin flexible foils that readily and rapidly attain a conformal contact with soft (shear modulus < 0.1 MPa) solid surfaces because of adhesive interfacial interactions. The conformal contact is established at all length scales by bending of the foil at scales larger than the feature size, in conjunction with the spontaneous elastic deformations of the surface on the scale of the features. For example, we used the protective aluminum foils of commercial data storage discs, both with or without data stored, for micron and sub-micron pattern transfer. The patterns are made permanent by UV-ozone treatment (for PDMS) or by controlled drying (for hydrogels). Interestingly, elastic contact imprinting of very thin (< 300 nm) films results in about 50% miniaturization of the original foil feature sizes. Complex two dimensional patterns could also be formed even by using a simple one dimensional master by multiple imprinting. The technique can be particularly useful for the bulk nano applications requiring routine fabrication of templates, for example, in the study of confined chemistry phenomena, nanofluidics, bio-MEMS, micro-imprinting, optical coatings and controlled dewetting.

  18. Methods for using polypeptides having cellobiohydrolase activity

    DOEpatents

    Morant, Marc D; Harris, Paul

    2016-08-23

    The present invention relates to isolated polypeptides having cellobiohydrolase activity and isolated polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.

  19. Real-time simulator for designing electron dual scattering foil systems.

    PubMed

    Carver, Robert L; Hogstrom, Kenneth R; Price, Michael J; LeBlanc, Justin D; Pitcher, Garrett M

    2014-11-08

    parameters have on a relative dose profile. This work also demonstrates a method for using the simulator as a design tool for creating custom dual scattering foil systems in the clinical range of beam energies (6-20 MeV). 

  20. Producing Foils From Direct Cast Titanium Alloy Strip

    NASA Technical Reports Server (NTRS)

    Stuart, T. A.; Gaspar, T. A.; Sukonnik, I. M.; Semiatan, S. L.; Batawi, E.; Peters, J. A.; Fraser, H. L.

    1996-01-01

    This research was undertaken to demonstrate the feasibility of producing high-quality, thin-gage, titanium foil from direct cast titanium strip. Melt Overflow Rapid Solidification Technology (MORST) was used to cast several different titanium alloys into 500 microns thick strip, 10 cm wide and up to 3 m long. The strip was then either ground, hot pack rolled or cold rolled, as appropriate, into foil. Gamma titanium aluminide (TiAl) was cast and ground to approximately 100 microns thick foil and alpha-2 titanium aluminide (Ti3AI) was cast and hot pack rolled to approximately 70 microns thick foil. CP Ti, Ti6Al2Sn4Zr2Mo, and Ti22AI23Nb (Orthorhombic), were successfully cast and cold-rolled into good quality foil (less than 125 microns thick). The foils were generally fully dense with smooth surfaces, had fine, uniform microstructures, and demonstrated mechanical properties equivalent to conventionally produced titanium. By eliminating many manufacturing steps, this technology has the potential to produce thin gage, titanium foil with good engineering properties at significantly reduced cost relative to conventional ingot metallurgy processing.

  1. Compliant Foil Journal Bearing Performance at Alternate Pressures and Temperatures

    NASA Technical Reports Server (NTRS)

    Bruckner, Robert J.; Puleo, Bernadette J.

    2008-01-01

    An experimental test program has been conducted to determine the highly loaded performance of current generation gas foil bearings at alternate pressures and temperatures. Typically foil bearing performance has been reported at temperatures relevant to turbomachinery applications but only at an ambient pressure of one atmosphere. This dearth of data at alternate pressures has motivated the current test program. Two facilities were used in the test program, the ambient pressure rig and the high pressure rig. The test program utilized a 35 mm diameter by 27 mm long foil journal bearing having an uncoated Inconel X-750 top foil running against a shaft with a PS304 coated journal. Load capacity tests were conducted at 3, 6, 9, 12, 15, 18, and 21 krpm at temperatures from 25 to 500 C and at pressures from 0.1 to 2.5 atmospheres. Results show an increase in load capacity with increased ambient pressure and a reduction in load capacity with increased ambient temperature. Below one-half atmosphere of ambient pressure a dramatic loss of load capacity is experienced. Additional lightly loaded foil bearing performance in nitrogen at 25 C and up to 48 atmospheres of ambient pressure has also been reported. In the lightly loaded region of operation the power loss increases for increasing pressure at a fixed load. Knowledge of foil bearing performance at operating conditions found within potential machine applications will reduce program development risk of future foil bearing supported turbomachines.

  2. Evaluation of methods to assess physical activity

    NASA Astrophysics Data System (ADS)

    Leenders, Nicole Y. J. M.

    Epidemiological evidence has accumulated that demonstrates that the amount of physical activity-related energy expenditure during a week reduces the incidence of cardiovascular disease, diabetes, obesity, and all-cause mortality. To further understand the amount of daily physical activity and related energy expenditure that are necessary to maintain or improve the functional health status and quality of life, instruments that estimate total (TDEE) and physical activity-related energy expenditure (PAEE) under free-living conditions should be determined to be valid and reliable. Without evaluation of the various methods that estimate TDEE and PAEE with the doubly labeled water (DLW) method in females there will be eventual significant limitations on assessing the efficacy of physical activity interventions on health status in this population. A triaxial accelerometer (Tritrac-R3D, (TT)), an uniaxial (Computer Science and Applications Inc., (CSA)) activity monitor, a Yamax-Digiwalker-500sp°ler , (YX-stepcounter), by measuring heart rate responses (HR method) and a 7-d Physical Activity Recall questionnaire (7-d PAR) were compared with the "criterion method" of DLW during a 7-d period in female adults. The DLW-TDEE was underestimated on average 9, 11 and 15% using 7-d PAR, HR method and TT. The underestimation of DLW-PAEE by 7-d PAR was 21% compared to 47% and 67% for TT and YX-stepcounter. Approximately 56% of the variance in DLW-PAEE*kgsp{-1} is explained by the registration of body movement with accelerometry. A larger proportion of the variance in DLW-PAEE*kgsp{-1} was explained by jointly incorporating information from the vertical and horizontal movement measured with the CSA and Tritrac-R3D (rsp2 = 0.87). Although only a small amount of variance in DLW-PAEE*kgsp{-1} is explained by the number of steps taken per day, because of its low cost and ease of use, the Yamax-stepcounter is useful in studies promoting daily walking. Thus, studies involving the

  3. Understanding undulatory locomotion in fishes using an inertia-compensated flapping foil robotic device.

    PubMed

    Wen, Li; Lauder, George

    2013-12-01

    Recent advances in understanding fish locomotion with robotic devices have included the use of flapping foil robots that swim at a constant swimming speed. However, the speed of even steadily swimming live fishes is not constant because the fish center of mass oscillates axially throughout a tail beat cycle. In this paper, we couple a linear motor that produces controlled oscillations in the axial direction to a robotic flapping foil apparatus to model both axial and side to side oscillatory motions used by freely-swimming fishes. This experimental arrangement allows us to compensate for the substantial inertia of the carriage and motors that drive the oscillating foils. We identify a 'critically-oscillated' amplitude of axial motion at which the cyclic oscillations in axial locomotor force are greatly reduced throughout the flapping cycle. We studied the midline kinematics, power consumption and wake flow patterns of non-rigid foils with different lengths and flexural stiffnesses at a variety of axial oscillation amplitudes. We found that 'critically-oscillated' peak-to-peak axial amplitudes on the order of 1.0 mm and at the correct phase are sufficient to mimic center of mass motion, and that such amplitudes are similar to center of mass oscillations recorded for freely-swimming live fishes. Flow visualization revealed differences in wake flows of flexible foils between the 'non-oscillated' and 'critically-oscillated' states. Inertia-compensating methods provide a novel experimental approach for studying aquatic animal swimming, and allow instrumented robotic swimmers to display center of mass oscillations similar to those exhibited by freely-swimming fishes.

  4. Commercial and cost effective production of Gas Electron Multiplier (GEM) Foils

    SciTech Connect

    Crary, David

    2010-05-05

    The nuclear and high energy physics research community is constantly searching for new and improved tracking and radiation detectors. The introduction of micropattern detectors has opened new opportunities for improving the rate capabilities, as well as the spatial and time resolution of particle detectors in these applications. GEM detectors in particular have received enormous interest for use in detectors planned for a number of new and upgraded experiments at many different research facilities. These include both the STAR and PHENIX experiments at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory, experiments at the Thomas Jefferson National Laboratory, Oak Ridge National Laboratory, and at the future electron-positron Linear Collider. At the present time, CERN is not able to supply foils in sufficient quantities to accommodate the needs of these experiments. Compounding this problem, there is a strong interest in GEM foils for numerous other applications, such as in astrophysics, medical imaging and detectors for homeland security. It would therefore be of significant benefit to the research community to develop a commercial source of GEM foils for all of these applications. Tech-Etch is in a unique position to develop this technology for commercial use. Tech-Etch has not only experience in numerous related high precision etched Kapton® products, but it also has strong ties with several research institutions (namely Brookhaven, Yale and MIT) that can help develop and evaluate the performance of the GEM foils produced at Tech-Etch. Additionally, since Tech-Etch is a small company, it also has the capability to produce a large variety of part configurations, as well as the flexibility to shift production methods, equipment, and chemistry to optimize the GEM foil manufacturing process without being constrained by existing work running on high volume continuous coil equipment.

  5. Effects of free surface on flow energy harvesting system based on flapping foils

    NASA Astrophysics Data System (ADS)

    Teng, Lubao; Deng, Jian; Shao, Xueming

    2016-11-01

    Here, we consider a flapping foil based energy harvester, which is modelled by a 2D NACA0015 foil performing coupled motions of pitching and heaving. Volume of fraction(VOF) method is employed to capture the free surface. We fix the Reynolds number at Re = 900 , and the Froude number at Fr = 0 . 32 . We fix the non-dimensional flapping frequency at f = 0 . 16 , the pitching amplitude at θ0 =75° , and the heaving amplitude at h0 = 1 c , where c is the chord length. With these parameters, the harvester has been proved to reach its highest efficiency of η = 0 . 34 in a single phase flow. By varying the submergence d, which is defined as the distance between the calm free surface and the highest position of the pitching pivot of the flapping foil, we find that the free surface affects pronouncedly the energy harvesting efficiency η. As d decreases from 24 c to 0 . 5 c , η increases from 0 . 34 to 0 . 41 , getting a 20% promotion of the efficiency. To reveal the underlying physical mechanism of the effects of free surface, we examine the time histories of hydrodynamic forces on the foil. We find that due to the existence of the the free surface, the lift force and pitching moment experience asymmetric time histories during the upstroke and downstroke of the foil. This research is supported by the National Natural Science Foundation of China (Grant No: 11272283) and the Public Projects of Zhejiang Province (Grant No: 2015C31126) to conduct this research.

  6. Commercial and Cost Effective Production of Gas Electron Multiplier (GEM) Foils

    SciTech Connect

    Woody, Craig

    2009-03-31

    The nuclear and high energy physics research community is constantly searching for new and improved tracking and radiation detectors. The introduction of micropattern detectors has opened new opportunities for improving the rate capabilities, as well as the spatial and time resolution of particle detectors in these applications. GEM detectors in particular have received enormous interest for use in detectors planned for a number of new and upgraded experiments at many different research facilities. These include both the STAR and PHENIX experiments at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory, experiments at the Thomas Jefferson National Laboratory, Oak Ridge National Laboratory, and at the future electron-positron Linear Collider. At the present time, CERN is not able to supply foils in sufficient quantities to accommodate the needs of these experiments. Compounding this problem, there is a strong interest in GEM foils for numerous other applications, such as in astrophysics, medical imaging and detectors for homeland security. It would therefore be of significant benefit to the research community to develop a commercial source of GEM foils for all of these applications. Tech-Etch is in a unique position to develop this technology for commercial use. Tech-Etch has not only experience in numerous related high precision etched Kapton® products, but it also has strong ties with several research institutions (namely Brookhaven, Yale and MIT) that can help develop and evaluate the performance of the GEM foils produced at Tech-Etch. Additionally, since Tech-Etch is a small company, it also has the capability to produce a large variety of part configurations, as well as the flexibility to shift production methods, equipment, and chemistry to optimize the GEM foil manufacturing process without being constrained by existing work running on high volume continuous coil equipment.

  7. Active music therapy and Parkinson's disease: methods.

    PubMed

    Pacchetti, C; Aglieri, R; Mancini, F; Martignoni, E; Nappi, G

    1998-01-01

    Music therapy (MT) is an unconventional, multisensorial therapy poorly assessed in medical care but widely used to different ends in a variety of settings. MT has two branches: active and passive. In active MT the utilisation of instruments is structured to correspond to all sensory organs so as to obtain suitable motor and emotional responses. We conducted a prospective study to evaluate the effects of MT in the neurorehabilitation of patients with Parkinson's Disease (PD), a common degenerative disorder involving movement and emotional impairment. Sixteen PD patients took part in 13 weekly sessions of MT each lasting 2 hours. At the beginning and at the end of the session, every 2 weeks, the patients were evaluated by a neurologist, who assessed PD severity with UPDRS, emotional functions with Happiness Measures (HM) and quality of life using the Parkinson's Disease Quality of Life Questionnaire (PDQL). After every session a significant improvement in motor function, particularly in relation to hypokinesia, was observed both in the overall and in the pre-post session evaluations. HM, UPDRS-ADL and PDQL changes confirmed an improving effect of MT on emotional functions, activities of daily living and quality of life. In conclusion, active MT, operating at a multisensorial level, stimulates motor, affective and behavioural functions. Finally, we propose active MT as new method to include in PD rehabilitation programmes. This article describes the methods adopted during MT sessions with PD patients.

  8. A novel carbon coating technique for foil bolometers.

    PubMed

    Sheikh, U A; Duval, B P; Labit, B; Nespoli, F

    2016-11-01

    Naked foil bolometers can reflect a significant fraction of incident energy and therefore cannot be used for absolute measurements. This paper outlines a novel coating approach to address this problem by blackening the surface of gold foil bolometers using physical vapour deposition. An experimental bolometer was built containing four standard gold foil bolometers, of which two were coated with 100+ nm of carbon. All bolometers were collimated and observed the same relatively high temperature, ohmically heated plasma. Preliminary results showed 13%-15% more incident power was measured by the coated bolometers and this is expected to be much higher in future TCV detached divertor experiments.

  9. Mechanical properties of micro- and nanocrystalline diamond foils

    PubMed Central

    Lodes, M. A.; Kachold, F. S.; Rosiwal, S. M.

    2015-01-01

    Diamond coating of suitable template materials and subsequent delamination allows for the manufacturing of free-standing diamond foil. The evolution of the microstructure can be influenced by secondary nucleation via control of process conditions in the hot-filament chemical vapour deposition process. Bending tests show extraordinarily high strength (more than 8 GPa), especially for diamond foils with nanocrystalline structure. A detailed fractographic analysis is conducted in order to correlate measured strength values with crack-initiating defects. The size of the failure causing flaw can vary from tens of micrometres to tens of nanometres, depending on the diamond foil microstructure as well as the loading conditions. PMID:25713455

  10. Functional multi-band THz meta-foils

    PubMed Central

    Wu, Jianfeng; Moser, Herbert O.; Xu, Su; Jian, Linke; Banas, Agnieszka; Banas, Krzysztof; Chen, Hongsheng; Bettiol, Andrew A.; Breese, Mark B. H.

    2013-01-01

    In this paper, we present the first experimental demonstration of double- and triple-band negative refraction index meta-foils in the terahertz (THz) region. Multi-band meta-foils constructed by multi-cell S-string resonators in a single structure exhibit simultaneously negative permittivity and negative permeability responses at multiple frequencies. The phenomena are confirmed by numerical simulations and Fourier transform infrared spectroscopy measurements. The flexible, freestanding multi-band meta-foils provide a promising candidate for the development of multi-frequency THz materials and devices. PMID:24346309

  11. Elevated Temperature Tensile Tests on DU–10Mo Rolled Foils

    SciTech Connect

    Schulthess, Jason

    2014-09-01

    Tensile mechanical properties for uranium-10 wt.% molybdenum (U–10Mo) foils are required to support modeling and qualification of new monolithic fuel plate designs. It is expected that depleted uranium-10 wt% Mo (DU–10Mo) mechanical behavior is representative of the low enriched U–10Mo to be used in the actual fuel plates, therefore DU-10Mo was studied to simplify material processing, handling, and testing requirements. In this report, tensile testing of DU-10Mo fuel foils prepared using four different thermomechanical processing treatments were conducted to assess the impact of foil fabrication history on resultant tensile properties.

  12. A novel carbon coating technique for foil bolometers

    NASA Astrophysics Data System (ADS)

    Sheikh, U. A.; Duval, B. P.; Labit, B.; Nespoli, F.

    2016-11-01

    Naked foil bolometers can reflect a significant fraction of incident energy and therefore cannot be used for absolute measurements. This paper outlines a novel coating approach to address this problem by blackening the surface of gold foil bolometers using physical vapour deposition. An experimental bolometer was built containing four standard gold foil bolometers, of which two were coated with 100+ nm of carbon. All bolometers were collimated and observed the same relatively high temperature, ohmically heated plasma. Preliminary results showed 13%-15% more incident power was measured by the coated bolometers and this is expected to be much higher in future TCV detached divertor experiments.

  13. [Bioluminescent method of determining antiprotease activity].

    PubMed

    Gitel'zon, I I; Rykov, S A; Kratasiuk, G A; Petushkov, V N; Shvetskiĭ, A G

    1985-11-01

    A method for antiprotease activity measurement based on the use of luminous bacteria luciferase as protein substrate of proteases is suggested. Antiprotease is incubated with protease for 1 to 2 min at 30 degrees C and then it is added to the reaction mixture containing luciferase, NADH: FMN-oxidoreductase and their substrates--myristic aldehyde, FMN and NADH. Biofluorescence is measured in a temperature-controlled cuvette for 1 min. The total time of the measurement is 3 min. The method can be applied both in fine biochemical assays and in medical rapid diagnosis.

  14. Method to produce catalytically active nanocomposite coatings

    DOEpatents

    Erdemir, Ali; Eryilmaz, Osman Levent; Urgen, Mustafa; Kazmanli, Kursat

    2016-02-09

    A nanocomposite coating and method of making and using the coating. The nanocomposite coating is disposed on a base material, such as a metal or ceramic; and the nanocomposite consists essentially of a matrix of an alloy selected from the group of Cu, Ni, Pd, Pt and Re which are catalytically active for cracking of carbon bonds in oils and greases and a grain structure selected from the group of borides, carbides and nitrides.

  15. Method for photon activation positron annihilation analysis

    DOEpatents

    Akers, Douglas W.

    2006-06-06

    A non-destructive testing method comprises providing a specimen having at least one positron emitter therein; determining a threshold energy for activating the positron emitter; and determining whether a half-life of the positron emitter is less than a selected half-life. If the half-life of the positron emitter is greater than or equal to the selected half-life, then activating the positron emitter by bombarding the specimen with photons having energies greater than the threshold energy and detecting gamma rays produced by annihilation of positrons in the specimen. If the half-life of the positron emitter is less then the selected half-life, then alternately activating the positron emitter by bombarding the specimen with photons having energies greater then the threshold energy and detecting gamma rays produced by positron annihilation within the specimen.

  16. A nanometric Rh overlayer on a metal foil surface as a highly efficient three-way catalyst

    PubMed Central

    Misumi, Satoshi; Yoshida, Hiroshi; Hinokuma, Satoshi; Sato, Tetsuya; Machida, Masato

    2016-01-01

    Pulsed arc-plasma (AP) deposition of an Rh overlayer on an Fe–Cr–Al stainless steel foil produced a composite material that exhibited high activity for automotive three-way catalysis (TWC). The AP pulses deposited metallic Rh nanoparticles 1–3 nm in size, whose density on the surface increased with the number of pulses. This led to coalescence and grain growth on the foil surface and the eventual formation of a uniform two-dimensional Rh overlayer. Full coverage of the 51 μm-thick flat foil by a 3.2 nm-thick Rh overlayer was achieved after 1,000 pulses. A simulated TWC reaction using a miniature honeycomb fabricated using flat and corrugated foils with the Rh overlayers exhibited successful light-off at a practical gaseous hourly space velocity of 1.2 × 105 h−1. The turnover frequency for the NO–CO reaction over the metallic honeycomb catalyst was ca. 80-fold greater than that achieved with a reference Rh/ZrO2-coated cordierite honeycomb prepared using a conventional wet impregnation and slurry coating procedure. Despite the nonporosity and low surface area of the foil-supported Rh overlayer compared with conventional powder catalysts (Rh/ZrO2), it is a promising alternative design for more efficient automotive catalysts that use less Rh loading. PMID:27388976

  17. A nanometric Rh overlayer on a metal foil surface as a highly efficient three-way catalyst.

    PubMed

    Misumi, Satoshi; Yoshida, Hiroshi; Hinokuma, Satoshi; Sato, Tetsuya; Machida, Masato

    2016-07-08

    Pulsed arc-plasma (AP) deposition of an Rh overlayer on an Fe-Cr-Al stainless steel foil produced a composite material that exhibited high activity for automotive three-way catalysis (TWC). The AP pulses deposited metallic Rh nanoparticles 1-3 nm in size, whose density on the surface increased with the number of pulses. This led to coalescence and grain growth on the foil surface and the eventual formation of a uniform two-dimensional Rh overlayer. Full coverage of the 51 μm-thick flat foil by a 3.2 nm-thick Rh overlayer was achieved after 1,000 pulses. A simulated TWC reaction using a miniature honeycomb fabricated using flat and corrugated foils with the Rh overlayers exhibited successful light-off at a practical gaseous hourly space velocity of 1.2 × 10(5) h(-1). The turnover frequency for the NO-CO reaction over the metallic honeycomb catalyst was ca. 80-fold greater than that achieved with a reference Rh/ZrO2-coated cordierite honeycomb prepared using a conventional wet impregnation and slurry coating procedure. Despite the nonporosity and low surface area of the foil-supported Rh overlayer compared with conventional powder catalysts (Rh/ZrO2), it is a promising alternative design for more efficient automotive catalysts that use less Rh loading.

  18. A nanometric Rh overlayer on a metal foil surface as a highly efficient three-way catalyst

    NASA Astrophysics Data System (ADS)

    Misumi, Satoshi; Yoshida, Hiroshi; Hinokuma, Satoshi; Sato, Tetsuya; Machida, Masato

    2016-07-01

    Pulsed arc-plasma (AP) deposition of an Rh overlayer on an Fe–Cr–Al stainless steel foil produced a composite material that exhibited high activity for automotive three-way catalysis (TWC). The AP pulses deposited metallic Rh nanoparticles 1–3 nm in size, whose density on the surface increased with the number of pulses. This led to coalescence and grain growth on the foil surface and the eventual formation of a uniform two-dimensional Rh overlayer. Full coverage of the 51 μm-thick flat foil by a 3.2 nm-thick Rh overlayer was achieved after 1,000 pulses. A simulated TWC reaction using a miniature honeycomb fabricated using flat and corrugated foils with the Rh overlayers exhibited successful light-off at a practical gaseous hourly space velocity of 1.2 × 105 h‑1. The turnover frequency for the NO–CO reaction over the metallic honeycomb catalyst was ca. 80-fold greater than that achieved with a reference Rh/ZrO2-coated cordierite honeycomb prepared using a conventional wet impregnation and slurry coating procedure. Despite the nonporosity and low surface area of the foil-supported Rh overlayer compared with conventional powder catalysts (Rh/ZrO2), it is a promising alternative design for more efficient automotive catalysts that use less Rh loading.

  19. Characterization of Electrodeposited Technetium on Gold Foil

    SciTech Connect

    Mausolf, Edward; Poineau, Frederic; Hartmann, Thomas; Droessler, Janelle; Czerwinski, Ken

    2011-11-17

    The reduction and electrodeposition of TcO{sub 4}{sup -} on a smooth gold foil electrode with an exposed area of 0.25 cm{sup 2} was performed in 1 M H{sub 2}SO{sub 4} supporting electrolyte using bulk electrolysis with a constant current density of 1.0 A/cm{sup 2} at a potential of -2.0 V. Significant hydrogen evolution accompanied the formation of Tc deposits. Tc concentrations consisted of 0.01 M and 2 x 10{sup -3} M and were electrodeposited over various times. Deposited fractions of Tc were characterized by powder x-ray diffraction, x-ray absorption fine structure spectroscopy, and scanning electron microscopy with the capability to measure semiquantitative elemental compositions by energy-dispersive x-ray emission spectroscopy. Results indicate the presence of Tc metal on all samples as the primary electrodeposited constituent for all deposition times and Tc concentrations. Thin films of Tc have been observed followed by the formation of beads that are removable by scratching. After 2000, the quantity of Tc removed from solution and deposited was 0.64 mg Tc per cm{sup 2}. The solution, after electrodeposition, showed characteristic absorbances near 500 nm corresponding to hydrolyzed Tc(IV) produced during deposition of Tc metal. No detectable Tc(IV) was deposited to the cathode.

  20. Stratification in Al and Cu foils exploded in vacuum

    SciTech Connect

    Baksht, R. B.; Rousskikh, A. G.; Zhigalin, A. S.; Artyomov, A. P.; Oreshkin, V. I.

    2015-10-15

    An experiment with exploding foils was carried out at a current density of 0.7 × 10{sup 8} A/cm{sup 2} through the foil with a current density rise rate of about 10{sup 15} A/cm{sup 2} s. To record the strata arising during the foil explosions, a two-frame radiographic system was used that allowed tracing the dynamics of strata formation within one shot. The original striation wavelength was 20–26 μm. It was observed that as the energy deposition to a foil stopped, the striation wavelength increased at a rate of ∼(5–9) × 10{sup 3} cm/s. It is supposed that the most probable reason for the stratification is the thermal instability that develops due to an increase in the resistivity of the metal with temperature.

  1. Moderation and diffusion of positrons in tungsten meshes and foils

    NASA Astrophysics Data System (ADS)

    Williams, A. I.; Murtagh, D. J.; Fayer, S. E.; Andersen, S. L.; Chevallier, J.; Kövér, Á.; Van Reeth, P.; Humberston, J. W.; Laricchia, G.

    2015-09-01

    The efficiency of tungsten meshes and thin foils for moderation of fast positrons from 22Na has been investigated in transmission geometry and a fair agreement has been found with previous experimental results where directly comparable. For foils, the dependence on material thickness is found to be similar to the prediction of the Vehanen-Mäkinen diffusion model; however, the magnitude is 5-10 times lower. A broad consensus is observed between experiment and the results of a three-dimensional model developed in this work. For a given thickness, meshes are found to be generally better than foils by around a factor of 10 with a maximum efficiency ( ˜10-3) comparable to that achieved with thin single crystal foils, in accord with previous measurements and the results of the present model.

  2. 21 CFR 189.301 - Tin-coated lead foil capsules for wine bottles.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Tin-coated lead foil capsules for wine bottles... lead foil capsules for wine bottles. (a) Tin-coated lead foil is composed of a lead foil coated on one... covering applied over the cork and neck areas) on wine bottles to prevent insect infestation, as a...

  3. 21 CFR 189.301 - Tin-coated lead foil capsules for wine bottles.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Tin-coated lead foil capsules for wine bottles... lead foil capsules for wine bottles. (a) Tin-coated lead foil is composed of a lead foil coated on one... covering applied over the cork and neck areas) on wine bottles to prevent insect infestation, as a...

  4. 21 CFR 189.301 - Tin-coated lead foil capsules for wine bottles.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Tin-coated lead foil capsules for wine bottles. 189... lead foil capsules for wine bottles. (a) Tin-coated lead foil is composed of a lead foil coated on one... covering applied over the cork and neck areas) on wine bottles to prevent insect infestation, as a...

  5. 21 CFR 189.301 - Tin-coated lead foil capsules for wine bottles.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Tin-coated lead foil capsules for wine bottles... lead foil capsules for wine bottles. (a) Tin-coated lead foil is composed of a lead foil coated on one... covering applied over the cork and neck areas) on wine bottles to prevent insect infestation, as a...

  6. Fabrication of implantable microelectrode arrays by laser cutting of silicone rubber and platinum foil

    NASA Astrophysics Data System (ADS)

    Schuettler, M.; Stiess, S.; King, B. V.; Suaning, G. J.

    2005-03-01

    A new method for fabrication of microelectrode arrays comprised of traditional implant materials is presented. The main construction principle is the use of spun-on medical grade silicone rubber as insulating substrate material and platinum foil as conductor (tracks, pads and electrodes). The silicone rubber and the platinum foil are patterned by laser cutting using an Nd:YAG laser and a microcontroller-driven, stepper-motor operated x-y table. The method does not require expensive clean room facilities and offers an extremely short design-to-prototype time of below 1 day. First prototypes demonstrate a minimal achievable feature size of about 30 µm. The work presented here was carried out at The University of Newcastle, Australia.

  7. A Novel Thermal Management Approach for Radial Foil Air Bearings

    DTIC Science & Technology

    2010-07-01

    Rossum (1). Since their discovery, foil bearings have been commonly used as rotor supports in air cycle machines (ACM’s) that are part of an...engines (6, 7). With air as the lubricant, foil bearings can successfully support high speed rotors in extreme temperature environments without the...low enough, can lead to rotor instability. On the other hand, a heavier preload will create higher start-up torque and lift-off speed requirements

  8. Evidence of muonium formation using thin gold foils in vacuum

    NASA Technical Reports Server (NTRS)

    Barnett, B. A.; Chang, C. Y.; Steinberg, P.; Yodh, G. B.; Orr, H. D.; Carroll, J. B.; Eckhause, M.; Kane, J. R.; Spence, C. B.; Hsieh, C. S.

    1977-01-01

    The production of thermal muonium in a vacuum region has been investigated using an array of 200 thin (about 1000 A thick) gold foils exposed to a stopping positive-muon beam. By examining the observed time dependence of the positive-muon decay spectra in various transverse magnetic field, it is estimated that the lower limit of the probability of muonium formation by these gold foils placed in vacuum was 0.28 plus or minus 0.05.

  9. A new method for FMRI activation detection

    NASA Astrophysics Data System (ADS)

    Wei, Jianing; Talavage, Thomas M.; Pollak, Ilya

    2009-02-01

    The objective of fMRI data analysis is to detect the region of the brain that gets activated in response to a specific stimulus presented to the subject. We develop a new algorithm for activation detection in event-related fMRI data. We utilize a forward model for fMRI data acquisition which explicitly incorporates physiological noise, scanner noise and the spatial blurring introduced by the scanner. After slice-by-slice image restoration procedure that independently restores each data slice corresponding to each time index, we estimate the parameters of the hemodynamic response function (HRF) model for each pixel of the restored data. In order to enforce spatial regularity in our estimates, we model the prior distribution of the HRF parameters as a generalized Gaussian Markov random field (GGMRF) model. We develop an algorithm to compute the maximum a posteriori (MAP) estimates of the parameters. We then threshold the amplitude parameters to obtain the final activation map. We illustrate our algorithm by comparing it with the widely used general linear model (GLM) method. In synthetic data experiments, under the same probability of false alarm, the probability of correct detection for our method is up to 15% higher than GLM. In real data experiments, through anatomical analysis and benchmark testing using block paradigm results, we demonstrate that our algorithm produces fewer false alarms than GLM.

  10. Induction Bonding of Prepreg Tape and Titanium Foil

    NASA Technical Reports Server (NTRS)

    Messier, Bernadette C.; Hinkley, Jeffrey A.; Johnston, Norman J.

    1998-01-01

    Hybrid structural laminates made of titanium foil and carbon fiber reinforced polymer composite offer a potential for improved performance in aircraft structural applications. To obtain information needed for the automated fabrication of hybrid laminates, a series of bench scale tests were conducted of the magnetic induction bonding of titanium foil and thermoplastic prepreg tape. Foil and prepreg specimens were placed in the gap of a toroid magnet mounted in a bench press. Several magnet power supplies were used to study power at levels from 0.5 to 1.75 kW and frequencies from 50 to 120 kHz. Sol-gel surface-treated titanium foil, 0.0125 cm thick, and PIXA/IM7 prepreg tape were used in several lay-up configurations. Data were obtained on wedge peel bond strength, heating rate, and temperature ramp over a range of magnet power levels and frequencies at different "power-on" times for several magnet gap dimensions. These data will be utilized in assessing the potential for automated processing. Peel strengths of foil-tape bonds depended on the maximum temperature reached during heating and on the applied pressure. Maximum peel strengths were achieved at 1.25kW and 8OkHz. Induction heating of the foil appears to be capable of good bonding up to 10 plies of tape. Heat transfer calculations indicate that a 20-40 C temperature difference exists across the tape thickness during heat-up.

  11. System and method for monitoring cellular activity

    NASA Technical Reports Server (NTRS)

    Bearman, Gregory H. (Inventor); Fraser, Scott E. (Inventor); Lansford, Russell D. (Inventor)

    2004-01-01

    A system and method for monitoring cellular activity in a cellular specimen. According to one embodiment, a plurality of excitable markers are applied to the specimen. A multi-photon laser microscope is provided to excite a region of the specimen and cause fluorescence to be radiated from the region. The radiating fluorescence is processed by a spectral analyzer to separate the fluorescence into respective wavelength bands. The respective bands of fluorescence are then collected by an array of detectors, with each detector receiving a corresponding one of the wavelength bands.

  12. System and method for monitoring cellular activity

    NASA Technical Reports Server (NTRS)

    Bearman, Gregory H. (Inventor); Fraser, Scott E. (Inventor); Lansford, Russell D. (Inventor)

    2002-01-01

    A system and method for monitoring cellular activity in a cellular specimen. According to one embodiment, a plurality of excitable markers are applied to the specimen. A multi-photon laser microscope is provided to excite a region of the specimen and cause fluorescence to be radiated from the region. The radiating fluorescence is processed by a spectral analyzer to separate the fluorescence into respective wavelength bands. The respective bands of fluorescence are then collected by an array of detectors, with each detector receiving a corresponding one of the wavelength bands.

  13. Dual stage active magnetic regenerator and method

    DOEpatents

    Pecharsky, Vitalij K.; Gschneidner, Jr., Karl A.

    1999-03-30

    A dual stage active magnetic regenerator refrigerator as well as method using the Joule-Brayton thermodynamic cycle includes a high temperature stage refrigerant comprising DyAl.sub.2 or (Dy.sub.1-x Er.sub.x)Al.sub.2 where x is selected to be greater than 0 and less than about 0.3 in combination with a low temperature stage comprising (Dy.sub.1-x Er.sub.x)Al.sub.2 where x is selected to be greater than about 0.5 and less than 1 to provide significantly improved refrigeration efficiency in the liquefaction of gaseous hydrogen.

  14. Dual stage active magnetic regenerator and method

    DOEpatents

    Pecharsky, V.K.; Gschneidner, K.A. Jr.

    1999-03-30

    A dual stage active magnetic regenerator refrigerator as well as method using the Joule-Brayton thermodynamic cycle includes a high temperature stage refrigerant comprising DyAl{sub 2} or (Dy{sub 1{minus}x}Er{sub x})Al{sub 2} where x is selected to be greater than 0 and less than about 0.3 in combination with a low temperature stage comprising (Dy{sub 1{minus}x}Er{sub x})Al{sub 2} where x is selected to be greater than about 0.5 and less than 1 to provide significantly improved refrigeration efficiency in the liquefaction of gaseous hydrogen. 17 figs.

  15. Growth of high-crystalline, single-layer hexagonal boron nitride on recyclable platinum foil.

    PubMed

    Kim, Gwangwoo; Jang, A-Rang; Jeong, Hu Young; Lee, Zonghoon; Kang, Dae Joon; Shin, Hyeon Suk

    2013-04-10

    Hexagonal boron nitride (h-BN) is gaining significant attention as a two-dimensional dielectric material, along with graphene and other such materials. Herein, we demonstrate the growth of highly crystalline, single-layer h-BN on Pt foil through a low-pressure chemical vapor deposition method that allowed h-BN to be grown over a wide area (8 × 25 mm(2)). An electrochemical bubbling-based method was used to transfer the grown h-BN layer from the Pt foil onto an arbitrary substrate. This allowed the Pt foil, which was not consumed during the process, to be recycled repeatedly. The UV-visible absorption spectrum of the single-layer h-BN suggested an optical band gap of 6.06 eV, while a high-resolution transmission electron microscopy image of the same showed the presence of distinct hexagonal arrays of B and N atoms, which were indicative of the highly crystalline nature and single-atom thickness of the h-BN layer. This method of growing single-layer h-BN over large areas was also compatible with use of a sapphire substrate.

  16. A novel monolithic LEU foil target based on a PVD manufacturing process for (99)Mo production via fission.

    PubMed

    Hollmer, Tobias; Petry, Winfried

    2016-12-01

    (99)Mo is the most widely used radioactive isotope in nuclear medicine. Its main production route is the fission of uranium. A major challenge for a reliable supply is the conversion from highly enriched uranium (HEU) to low enriched uranium (LEU). A promising candidate to realize this conversion is the cylindrical LEU irradiation target. The target consists of a uranium foil encapsulated between two coaxial aluminum cladding cylinders. This target allows a separate processing of the irradiated uranium foil and the cladding when recovering the (99)Mo. Thereby, both the costs and the volume of highly radioactive liquid waste are significantly reduced compared to conventional targets. The presented manufacturing process is based on the direct coating of the uranium on the inside of the outer cladding cylinder. This process was realized by a cylindrical magnetron enhanced physical vapor deposition (PVD) technique. The method features a highly automated process, a good quality of the resulting uranium foils and a high material utilization.

  17. Generating femtosecond X-ray pulses using an emittance-spoiling foil in free-electron lasers

    SciTech Connect

    Ding, Y. Coffee, R.; Decker, F.-J.; Emma, P.; Field, C.; Huang, Z.; Krejcik, P.; Krzywinski, J.; Loos, H.; Lutman, A.; Marinelli, A.; Maxwell, T. J.; Turner, J.; Behrens, C.; Helml, W.

    2015-11-09

    Generation of femtosecond to sub-femtosecond pulses is attracting much attention in X-ray free-electron laser user community. One method is to use a slotted, emittance-spoiling foil which was proposed before (P. Emma et al., Phys. Rev. Lett. 92, 074801 (2004)) and has been widely used at the Linac Coherent Light Source. Direct experimental characterization of the slotted-foil performance was previously unfeasible due to a lack of appropriate diagnostics. With a recently installed X-band radio-frequency transverse deflector, we are able to characterize the electron bunch spoiling effect and X-ray pulse when using the slotted foil. We show that few-femtosecond X-ray pulses are generated with flexible control of the single-pulse duration or double-pulse separation with comparison to the theoretical model.

  18. Instrumentation for measurement of in-flight annihilations of 130 keV antiprotons on thin target foils

    NASA Astrophysics Data System (ADS)

    Todoroki, K.; Barna, D.; Hayano, R. S.; Aghai-Khozani, H.; Sótér, A.; Corradini, M.; Leali, M.; Lodi-Rizzini, E.; Mascagna, V.; Venturelli, L.; Prest, V.; Vallazza, L.; De Salvador, D.; Hori, M.

    2016-11-01

    We describe the instrumentation for an experiment to measure the cross sections of antiprotons with kinetic energies of 130±10 keV annihilating on carbon, palladium, and platinum target foils of sub-100 nm thicknesses. A 120 ns long pulsed beam containing 105 -106 antiprotons was allowed to traverse the foils, and the signal annihilations that resulted from this were isolated using a time-of-flight method. Backgrounds arose from Rutherford scattering of the antiprotons off the target foils, their annihilations in the target chamber walls, and π → μ → e decay of the charged pions that emerged from the annihilations. Some antiprotons slowed down and annihilated in the contamination on the target surfaces. This reduced the signal-to-background ratio of the measurement.

  19. Simulation of the generation of the characteristic X-ray emission by hot electrons in a foil

    SciTech Connect

    Kostenko, O F; Andreev, N E

    2013-03-31

    We have developed a model to calculate the yield of the characteristic X-ray radiation from a foil, taking into account the dependence of the average energy and the number of hot electrons on the intensity of the laser pulse, the self-absorption of X-rays and the effect of refluxing of hot electrons. The yield of K{sub {alpha}} radiation from a silver foil is optimised at relativistic intensities. A method is proposed for diagnosing the effect of electron refluxing, which greatly increases the yield of K{sub {alpha}} radiation. (extreme light fields and their applications)

  20. The surface condition effect of Cu2O flower/grass-like nanoarchitectures grown on Cu foil and Cu film

    NASA Astrophysics Data System (ADS)

    Hu, Lijiao; Ju, Yang; Hosoi, Atsushi; Tang, Yongpeng

    2013-10-01

    Cu2O flower/grass-like nanoarchitectures (FGLNAs) were fabricated directly on two category specimens of Cu foils and Cu film using thermal oxidation method. The FGLNAs are approximately 3.5 to 12 μm in size, and their petals are approximately 50 to 950 nm in width. The high compressive stress caused by a large oxide volume in the Cu2O layer on the specimen surface played an important role in the growth of FGLNAs. The effects of surface conditions, such as the surface stresses, grain size, and surface roughness of Cu foil and Cu film specimens, on the FGLNA growth were discussed in detail.

  1. A comparison of results obtained from foil chaff clouds at 69 deg northern latitude during winter, summer and autumn

    NASA Technical Reports Server (NTRS)

    Widdel, H. U.; Vonzahn, U.

    1989-01-01

    Results from high resolution foil chaff experiments flown during the campaigns MAP/WINE (December 83 to February 84), MAC/SINE (June to July 1987) and Epsilon (October to November 1987) at Andenes (Northern Norway) are compared to each other and the differences in wind direction and wave activity during the different seasons are worked out.

  2. Effects study on the thermal stresses in a LEU metal foil annular target.

    PubMed

    Govindarajan, Srisharan G; Solbrekken, Gary L

    2015-09-01

    The effects of fission gas pressure, uranium swelling and thermal contact conductance on the thermal-mechanical behavior of an annular target containing a low-enriched uranium foil (LEU) encapsulated in a nickel foil have been presented in this paper. The draw-plug assembly method is simulated to obtain the residual stresses, which are applied to the irradiation model as initial inputs, and the integrated assembly-irradiation process is simulated as an axisymmetric problem using the commercial finite element code Abaqus FEA. Parametric studies were performed on the LEU heat generation rate and the results indicate satisfactory irradiation performance of the annular target. The temperature and stress margins have been provided along with a discussion of the results.

  3. Numerical investigation of the transverse instability on the radiation-pressure-driven foil.

    PubMed

    Wang, W Q; Yin, Y; Yu, T P; Xu, H; Zou, D B; Shao, F Q

    2015-12-01

    The development of transverse instability in the radiation-pressure-acceleration dominant laser-foil interaction is numerically examined by two-dimensional particle-in-cell simulations. When a plane laser impinges on a foil with modulated surface, the transverse instability is incited, and periodic perturbations of the proton density develop. The growth rate of the transverse instability is numerically diagnosed. It is found that the linear growth of the transverse instability lasts only a few laser periods, then the instability gets saturated. In order to optimize the modulation wavelength of the target, a method of information entropy is put forward to describe the chaos degree of the transverse instability. With appropriate modulation, the transverse instability shows a low chaos degree, and a quasi-monoenergetic proton beam is produced.

  4. A Microfabricated Involute-Foil Regenerator for Stirling Engines

    NASA Technical Reports Server (NTRS)

    Tew, Roy; Ibrahim, Mounir; Danila, Daniel; Simon, Terry; Mantell, Susan; Sun, Liyong; Gedeon, David; Kelly, Kevin; McLean, Jeffrey; Wood, Gary; Qiu, Songgang

    2007-01-01

    A segmented involute-foil regenerator has been designed, microfabricated and tested in an oscillating-flow rig with excellent results. During the Phase I effort, several approximations of parallel-plate regenerator geometry were chosen as potential candidates for a new microfabrication concept. Potential manufacturers and processes were surveyed. The selected concept consisted of stacked segmented-involute-foil disks (or annular portions of disks), originally to be microfabricated from stainless-steel via the LiGA (lithography, electroplating, and molding) process and EDM (electric discharge machining). During Phase II, re-planning of the effort led to test plans based on nickel disks, microfabricated via the LiGA process, only. A stack of nickel segmented-involute-foil disks was tested in an oscillating-flow test rig. These test results yielded a performance figure of merit (roughly the ratio of heat transfer to pressure drop) of about twice that of the 90% random fiber currently used in small 100 W Stirling space-power convertors in the Reynolds Number range of interest (50-100). A Phase III effort is now underway to fabricate and test a segmented-involute-foil regenerator in a Stirling convertor. Though funding limitations prevent optimization of the Stirling engine geometry for use with this regenerator, the Sage computer code will be used to help evaluate the engine test results. Previous Sage Stirling model projections have indicated that a segmented-involute-foil regenerator is capable of improving the performance of an optimized involute-foil engine by 6-9%; it is also anticipated that such involute-foil geometries will be more reliable and easier to manufacture with tight-tolerance characteristics, than random-fiber or wire-screen regenerators. Beyond the near-term Phase III regenerator fabrication and engine testing, other goals are (1) fabrication from a material suitable for high temperature Stirling operation (up to 850 C for current engines; up to

  5. A Microfabricated Involute-Foil Regenerator for Stirling Engines

    NASA Technical Reports Server (NTRS)

    Tew, Roy; Ibrahim, Mounir; Danila, Daniel; Simon, Terrence; Mantell, Susan; Sun, Liyong; Gedeon, David; Kelly, Kevin; McLean, Jeffrey; Qiu, Songgang

    2007-01-01

    A segmented involute-foil regenerator has been designed, microfabricated and tested in an oscillating-flow rig with excellent results. During the Phase I effort, several approximations of parallel-plate regenerator geometry were chosen as potential candidates for a new microfabrication concept. Potential manufacturers and processes were surveyed. The selected concept consisted of stacked segmented-involute-foil disks (or annular portions of disks), originally to be microfabricated from stainless-steel via the LiGA (lithography, electroplating, and molding) process and EDM. During Phase II, re-planning of the effort led to test plans based on nickel disks, microfabricated via the LiGA process, only. A stack of nickel segmented-involute-foil disks was tested in an oscillating-flow test rig. These test results yielded a performance figure of merit (roughly the ratio of heat transfer to pressure drop) of about twice that of the 90 percent random fiber currently used in small approx.100 W Stirling space-power convertors-in the Reynolds Number range of interest (50 to 100). A Phase III effort is now underway to fabricate and test a segmented-involute-foil regenerator in a Stirling convertor. Though funding limitations prevent optimization of the Stirling engine geometry for use with this regenerator, the Sage computer code will be used to help evaluate the engine test results. Previous Sage Stirling model projections have indicated that a segmented-involute-foil regenerator is capable of improving the performance of an optimized involute-foil engine by 6 to 9 percent; it is also anticipated that such involute-foil geometries will be more reliable and easier to manufacture with tight-tolerance characteristics, than random-fiber or wire-screen regenerators. Beyond the near-term Phase III regenerator fabrication and engine testing, other goals are (1) fabrication from a material suitable for high temperature Stirling operation (up to 850 C for current engines; up to 1200 C

  6. Instabilities in foil implosions and the effect of radiation output

    SciTech Connect

    Oona, H.; Peterson, D.L.; Goforth, J.H.

    1995-08-01

    One of the aims of the Athena program at the Los Alamos National Laboratory is the generation of a high fluence of soft x-rays from the thermalization of an radially imploding foil. In the experiments in Athena program, a large axial current is passed through a cylindrical aluminum foil. Under the action of the Lorentz force, the resulting plasma accelerates toward the axis, thermalizes, and produces a fast soft x-ray pulse with a blackbody temperature up to several hundred electron volts. In order that there be the maximum power compression and the highest x-ray fluence and temperature, the plasma stagnation on axis must occur very promptly. This requires that the imploding plasma be as thin and symmetric as possible. A serious problem in the thermalization process is the formation of instabilities in the plasma due to the self-magnetic field that governs the implosion of foil. A large diagnostic effort was developed to capture the details of the implosion and instability growth in several foil implosion experiments. In this report, we will present visible light images and x-ray data designed to study the effects of foil mass, current, and initial perturbations on the instability growth during foil implosion. Representative data is presented from several experiments using the Pegasus capacitor bank system and the explosively driven Procyon system. These experiments are labeled Peg 25 and Peg 33 for the Pegasus experiments and PDD1, PDD2 and PRF0 for the Procyon experiments. In these experiments, all foils had radii of 5 centimeters but varied in mass and initial conditions. Experimental data from several shots were compared with each other and to a radiation magnetohydrodynamic (RMHD) computation and described in a separate paper.

  7. Determination of (222)Rn absorption properties of polycarbonate foils by liquid scintillation counting. Application to (222)Rn measurements.

    PubMed

    Mitev, K; Cassette, P; Georgiev, S; Dimitrova, I; Sabot, B; Boshkova, T; Tartès, I; Pressyanov, D

    2016-03-01

    This work demonstrates that a Liquid Scintillation Counting (LSC) technique using a Triple to Double Coincidence Ratio counter with extending dead-time is very appropriate for the accurate measurement of (222)Rn activity absorbed in thin polycarbonate foils. It is demonstrated that using a toluene-based LS cocktail, which dissolves polycarbonates, the (222)Rn activity absorbed in thin Makrofol N foil can be determined with a relative standard uncertainty of about 0.7%. A LSC-based application of the methodology for determination of the diffusion length of (222)Rn in thin polycarbonate foils is proposed and the diffusion length of (222)Rn in Makrofol N (38.9±1.3µm) and the partition coefficient of (222)Rn in Makrofol N from air (112±12, at 20°C) and from water (272±17, at 21°C) are determined. Calibration of commercial LS spectrometers for (222)Rn measurements by LSC of thin polycarbonate foils is performed and the minimum detectable activities by this technique are estimated.

  8. Actively controlled vibration welding system and method

    DOEpatents

    Cai, Wayne W.; Kang, Bongsu; Tan, Chin-An

    2013-04-02

    A vibration welding system includes a controller, welding horn, an active material element, and anvil assembly. The assembly may include an anvil body connected to a back plate and support member. The element, e.g., a piezoelectric stack or shape memory alloy, is positioned with respect to the assembly. The horn vibrates in a desirable first direction to form a weld on a work piece. The element controls any vibrations in a second direction by applying calibrated response to the anvil body in the second direction. A method for controlling undesirable vibrations in the system includes positioning the element with respect to the anvil assembly, connecting the anvil body to the support member through the back plate, vibrating the horn in a desirable first direction, and transmitting an input signal to the element to control vibration in an undesirable second direction.

  9. Method and apparatus for corrugating strips

    DOEpatents

    Day, Jack R.; Curtis, Charles H.

    1983-01-01

    The invention relates to a method and a machine for transversely corrugating a continuous strip of metallic foil. The product foil comprises a succession of alternately disposed corrugations, each defining in cross section, a major segment of a circle. The foil to be corrugated is positioned to extend within a vertical passage in the machine. The walls of the passage are heated to promote the desired deformation of the foil. Foil-deforming rollers are alternately passed obliquely across the passage to respectively engage transverse sections of the foil. The rollers and their respective section of deformed foil comprise a stacked assembly which is moved incrementally through the heated passageway. As the assembly emerges from the passageway, the rollers spill from the corrugated foil and are recovered for re-use.

  10. Method and apparatus for corrugating strips

    DOEpatents

    Day, J.R.; Curtis, C.H.

    1981-10-27

    The invention relates to a method and a machine for transversely corrugating a continuous strip of metallic foil. The product foil comprises a succession of alternately disposed corrugations, each defining in a cross section, a major segment of a circle. The foil to be corrugated is positioned to extend within a vertical passage in the machine. The walls of the passage are heated to promote the desired deformation of the foil. Foil-deforming rollers are alternately passed obliquely across the passage to respectively engage transverse sections of the foil. The rollers and their respective section of deformed foil comprise a stacked assembly which is moved incrementally through the heated passageway. As the assembly emerges from the passageway, the rollers spill from the corrugated foil and are recovered for re-use.

  11. D-Cluster Converter Foil for Laser-Accelerated Deuteron Beams: Towards Deuteron-Beam-Driven Fast Ignition

    SciTech Connect

    Miley, George H.

    2012-10-24

    Fast Ignition (FI) uses Petawatt laser generated particle beam pulse to ignite a small volume called a pre-compressed Inertial Confinement Fusion (ICF) target, and is the favored method to achieve the high energy gain per target burn needed for an attractive ICF power plant. Ion beams such as protons, deuterons or heavier carbon ions are especially appealing for FI as they have relative straight trajectory, and easier to focus on the fuel capsule. But current experiments have encountered problems with the 'converter-foil' which is irradiated by the Petawatt laser to produce the ion beams. The problems include depletion of the available ions in the convertor foils, and poor energy efficiency (ion beam energy/ input laser energy). We proposed to develop a volumetrically-loaded ultra-high-density deuteron deuterium cluster material as the basis for converter-foil for deuteron beam generation. The deuterons will fuse with the ICF DT while they slow down, providing an extra 'bonus' energy gain in addition to heating the hot spot. Also, due to the volumetric loading, the foil will provide sufficient energetic deuteron beam flux for 'hot spot' ignition, while avoiding the depletion problem encountered by current proton-driven FI foils. After extensive comparative studies, in Phase I, high purity PdO/Pd/PdO foils were selected for the high packing fraction D-Cluster converter foils. An optimized loading process has been developed to increase the cluster packing fraction in this type of foil. As a result, the packing fraction has been increased from 0.1% to 10% - meeting the original Phase I goal and representing a significant progress towards the beam intensities needed for both FI and pulsed neutron applications. Fast Ignition provides a promising approach to achieve high energy gain target performance needed for commercial Inertial Confinement Fusion (ICF). This is now a realistic goal for near term in view of the anticipated ICF target burn at the National Ignition

  12. Measurements of electric properties using an open-ended probe blocked by a non-conducting foil

    NASA Astrophysics Data System (ADS)

    Wolny, Alicja; Orzechowski, Kazimierz; Rudowski, Marek

    An open-ended coaxial probe separated from the investigated medium by a thin non-conducting layer (foil) is proposed for making dielectric permittivity measurements within the RF range. The method was originally applied by the authors for intraoperative tissue assessment, but it could also be suitable for food control (requirement of purity) or measurements in aggressive media (protection from corrosion).

  13. Gas Foil Bearings for Space Propulsion Nuclear Electric Power Generation

    NASA Technical Reports Server (NTRS)

    Howard, Samuel A.; DellaCorte, Christopher

    2006-01-01

    The choice of power conversion technology is critical in directing the design of a space vehicle for the future NASA mission to Mars. One candidate design consists of a foil bearing supported turbo alternator driven by a helium-xenon gas mixture heated by a nuclear reactor. The system is a closed-loop, meaning there is a constant volume of process fluid that is sealed from the environment. Therefore, foil bearings are proposed due to their ability to use the process gas as a lubricant. As such, the rotor dynamics of a foil bearing supported rotor is an important factor in the eventual design. The current work describes a rotor dynamic analysis to assess the viability of such a system. A brief technology background, assumptions, analyses, and conclusions are discussed in this report. The results indicate that a foil bearing supported turbo alternator is possible, although more work will be needed to gain knowledge about foil bearing behavior in helium-xenon gas.

  14. Misalignment in Gas Foil Journal Bearings: An Experimental Study

    NASA Technical Reports Server (NTRS)

    Howard, Samuel A.

    2008-01-01

    As gas foil journal bearings become more prevalent in production machines, such as small gas turbine propulsion systems and microturbines, system-level performance issues must be identified and quantified in order to provide for successful design practices. Several examples of system-level design parameters that are not fully understood in foil bearing systems are thermal management schemes, alignment requirements, balance requirements, thrust load balancing, and others. In order to address some of these deficiencies and begin to develop guidelines, this paper presents a preliminary experimental investigation of the misalignment tolerance of gas foil journal bearing systems. Using a notional gas foil bearing supported rotor and a laser-based shaft alignment system, increasing levels of misalignment are imparted to the bearing supports while monitoring temperature at the bearing edges. The amount of misalignment that induces bearing failure is identified and compared to other conventional bearing types such as cylindrical roller bearings and angular contact ball bearings. Additionally, the dynamic response of the rotor indicates that the gas foil bearing force coefficients may be affected by misalignment.

  15. System Being Developed to Measure the Rotordynamic Characteristics of Air Foil Bearings

    NASA Technical Reports Server (NTRS)

    Howard, Samuel A.; DellaCorte, Christopher; Valco, Mark J.

    2000-01-01

    Because of the many possible advantages of oil-free engine operation, interest in using air lubricated foil-bearing technology in advanced oil-free engine concepts has recently increased. The Oil-Free Turbomachinery Program at the NASA Glenn Research Center at Lewis Field has partially driven this recent push for oil-free technology. The program's goal of developing an innovative, practical, oil-free gas turbine engine for aeropropulsion began with the development of NASA's high-temperature solid-lubricant coating, PS304. This coating virtually eliminates the life-limiting wear that occurs during the startup and shutdown of the bearings. With practically unlimited life, foil air bearings are now very attractive to rotating machinery designers for use in turbomachinery. Unfortunately, the current knowledge base of these types of bearings is limited. In particular, the understanding of how these types of bearings contribute to the rotordynamic stability of turbomachinery is insufficient for designers to design with confidence. Recent work in oil-free turbomachinery has concentrated on advancing the understanding of foil bearings. A high-temperature fiber-optic displacement probe system and measurement method were developed to study the effects of speed, load, temperature, and other environmental issues on the stiffness characteristics of air foil bearings. Since high temperature data are to be collected in future testing, the testing method was intentionally simplified to minimize the need for expensive test hardware. The method measures the displacement induced upon a bearing in response to an applied perturbation load. The early results of these studies, which are shown in the accompanying figure, indicate trends in steady state stiffness that suggest stiffness increases with load and decreases with speed. It can be seen, even from these data, that stiffness is not expected to change by orders of magnitude over the normal operating range of most turbomachinery; a

  16. Experimental determination of the rotor dynamic coefficients of a gas-lubricated foil journal bearing

    NASA Astrophysics Data System (ADS)

    Hurley, Keith Alan

    1998-12-01

    This thesis describes an experimental investigation of the dynamic stiffness and damping characteristics of an air lubricated leaf-type foil journal bearing. A test bed with dynamic force and response measurement capabilities has been designed and fabricated as a part of the research effort. The test bed consists of a two inch diameter rotor which is supported on two hydrostatic air bearings. The test bearing is centered on the test rotor. The test bed has rotor speed capability of up to 30,000 rpm. Transverse static and dynamic loads of up to 100 lbs can be applied to the test bearing. Direct and cross-coupled transverse stiffness and damping coefficients for a two inch diameter by two inch long eight-leaf foil bearing are obtained using a frequency domain estimation algorithm. Foil bearing dynamic coefficient data is presented for a range of average bearing loads, rotor speeds, and whirl frequency ratios. Experimental predictions of dynamic coefficients for a plain rigid test bearing have been obtained for test bed validation purposes. These experimental results are shown to be in good agreement with corresponding theoretical predictions of rigid bearing dynamic coefficients obtained using a linearized perturbation analysis method. Simulated data has been used to investigate the effects of sensor calibration error and quantization error on the prediction of dynamic coefficients. The results of these investigations are also presented. A rotordynamic analysis is also presented and demonstrates how the dynamic coefficient data can be used to obtain a quantitative assessment of rotor/bearing system stability and frequency response characteristics. Dynamic response characteristics for rigid and compliant surface bearings are compared. The results substantiate the notion that foil bearings have enhanced dynamic performance characteristics in comparison to their rigid bearing counterparts.

  17. Damage suppression system using embedded SMA (shape memory alloy) foils in CFRP laminate structures

    NASA Astrophysics Data System (ADS)

    Ogisu, Toshimichi; Shimanuki, Masakazu; Kiyoshima, Satoshi; Takaki, Junji; Takeda, Nobuo

    2003-08-01

    This paper presents an overview of the demonstrator program with respect to the damage growth suppression effects using embedded SMA foils in CFRP laminates. The damage growth suppression effects were demonstrated for the technical verification in order to apply to aircraft structure. In our previous studies, the authors already confirmed the damage growth suppression effects of CFRP laminates with embedded pre-strained SMA foils through both coupon and structural element tests. It was founded that these effects were obtained by the suppression of the strain energy release rate based on the suppression of the crack opening displacement due to the recovery stress of SMA foils through the detail observation of the damage behavior. In this study, these results were verified using the demonstrator test article, which was 1/3-scaled model of commercial airliner fuselage structure. For the demonstration of damage growth suppression effects, the evaluation area was located in the lower panel, which was dominated in tension load during demonstration. The evaluation area is the integrated stiffened panel including both "smart area" (CFRP laminate with embedded pre-strained SMA foils) and "conventional area" (standard CFRP laminate) for the direct comparison. The demonstration was conducted at 80 degree Celsius in smart area and room temperature (RT) in conventional area during quasi-static load-unload test method. As the test results, the demonstrator test article presented that the damage onset strain in the smart area was improved by 30% for compared with the conventional area. Therefore, the successful technical verification of the damage onset/growth suppression effect using the demonstrator presented the feasibility of the application of smart material and structural system to aircraft structures.

  18. A New Electrochemical Approach for the Synthesis of Copper-Graphene Nanocomposite Foils with High Hardness

    PubMed Central

    Pavithra, Chokkakula L. P.; Sarada, Bulusu V.; Rajulapati, Koteswararao V.; Rao, Tata N.; Sundararajan, G.

    2014-01-01

    Graphene has proved its significant role as a reinforcement material in improving the strength of polymers as well as metal matrix composites due to its excellent mechanical properties. In addition, graphene is also shown to block dislocation motion in a nanolayered metal-graphene composites resulting in ultra high strength. In the present paper, we demonstrate the synthesis of very hard Cu-Graphene composite foils by a simple, scalable and economical pulse reverse electrodeposition method with a well designed pulse profile. Optimization of pulse parameters and current density resulted in composite foils with well dispersed graphene, exhibiting a high hardness of ~2.5 GPa and an increased elastic modulus of ~137 GPa while exhibiting an electrical conductivity comparable to that of pure Cu. The pulse parameters are designed in such a way to have finer grain size of Cu matrix as well as uniform dispersion of graphene throughout the matrix, contributing to high hardness and modulus. Annealing of these nanocomposite foils at 300°C, neither causes grain growth of the Cu matrix nor deteriorates the mechanical properties, indicating the role of graphene as an excellent reinforcement material as well as a grain growth inhibitor. PMID:24514043

  19. A New Electrochemical Approach for the Synthesis of Copper-Graphene Nanocomposite Foils with High Hardness

    NASA Astrophysics Data System (ADS)

    Pavithra, Chokkakula L. P.; Sarada, Bulusu V.; Rajulapati, Koteswararao V.; Rao, Tata N.; Sundararajan, G.

    2014-02-01

    Graphene has proved its significant role as a reinforcement material in improving the strength of polymers as well as metal matrix composites due to its excellent mechanical properties. In addition, graphene is also shown to block dislocation motion in a nanolayered metal-graphene composites resulting in ultra high strength. In the present paper, we demonstrate the synthesis of very hard Cu-Graphene composite foils by a simple, scalable and economical pulse reverse electrodeposition method with a well designed pulse profile. Optimization of pulse parameters and current density resulted in composite foils with well dispersed graphene, exhibiting a high hardness of ~2.5 GPa and an increased elastic modulus of ~137 GPa while exhibiting an electrical conductivity comparable to that of pure Cu. The pulse parameters are designed in such a way to have finer grain size of Cu matrix as well as uniform dispersion of graphene throughout the matrix, contributing to high hardness and modulus. Annealing of these nanocomposite foils at 300°C, neither causes grain growth of the Cu matrix nor deteriorates the mechanical properties, indicating the role of graphene as an excellent reinforcement material as well as a grain growth inhibitor.

  20. A new electrochemical approach for the synthesis of copper-graphene nanocomposite foils with high hardness.

    PubMed

    Pavithra, Chokkakula L P; Sarada, Bulusu V; Rajulapati, Koteswararao V; Rao, Tata N; Sundararajan, G

    2014-02-11

    Graphene has proved its significant role as a reinforcement material in improving the strength of polymers as well as metal matrix composites due to its excellent mechanical properties. In addition, graphene is also shown to block dislocation motion in a nanolayered metal-graphene composites resulting in ultra high strength. In the present paper, we demonstrate the synthesis of very hard Cu-Graphene composite foils by a simple, scalable and economical pulse reverse electrodeposition method with a well designed pulse profile. Optimization of pulse parameters and current density resulted in composite foils with well dispersed graphene, exhibiting a high hardness of ~2.5 GPa and an increased elastic modulus of ~137 GPa while exhibiting an electrical conductivity comparable to that of pure Cu. The pulse parameters are designed in such a way to have finer grain size of Cu matrix as well as uniform dispersion of graphene throughout the matrix, contributing to high hardness and modulus. Annealing of these nanocomposite foils at 300°C, neither causes grain growth of the Cu matrix nor deteriorates the mechanical properties, indicating the role of graphene as an excellent reinforcement material as well as a grain growth inhibitor.

  1. Preparation of /sup 248/CmF/sub 3/ deposits on self-supported carbon foils

    SciTech Connect

    Aaron, W.S.; Petek, M.; Zevenbergen, L.A.

    1986-01-01

    Another target preparative technique was recently added to the Isotope Research Materials Laboratory's (IRML) capabilities for custom target fabrication. In support of super-heavy-ion physics experiments, methods and equipment were developed for the preparation of /sup 248/CmF/sub 3/ deposits on carbon foils. The starting material was obtained as either a chloride or nitrate solution, converted to the fluoride, and evaporated on carbon foil substrates. Deposits ranging from 40 to 570 ..mu..g/cm/sup 2/ were prepared as a 12-mm-diam spot on 45- to 60-..mu..g/cm/sup 2/ self-supported carbon foils. The deposits were then overcoated with approximately 10 ..mu..g/cm/sup 2/ of carbon to minimize contamination problems during target handling. The high cost of /sup 248/Cm ($100/..mu..g) and its limited availability were the key constraints in the development of preparative technology beyond the inherent radioactivity of /sup 248/Cm. 2 refs., 8 figs.

  2. Microstructure Evolution and Composition Control During the Processing of Thin-Gage Metallic Foil

    NASA Astrophysics Data System (ADS)

    Semiatin, S. L.; Gross, M. E.; Matson, D. W.; Bennett, W. D.; Bonham, C. C.; Ustinov, A. I.; Ballard, D. L.

    2012-12-01

    The manufacture of thin-gage superalloy and gamma-titanium-aluminide foil products via near-conventional thermomechanical processing and two different vapor-deposition methods was investigated. Thermomechanical processing was based on hot-pack rolling of plate and sheet. Foils of the superalloy LSHR and the near-gamma titanium aluminide Ti-45.5Al-2Cr-2Nb made by this approach exhibited excellent gage control and fine two-phase microstructures. The vapor-phase techniques used magnetron sputtering (MS) of a target of the desired product composition or electron-beam physical vapor deposition (EBPVD) of separate targets of the specific alloying elements. Thin deposits of LSHR and Ti-48Al-2Cr-2Nb made by MS showed uniform thickness/composition and an ultrafine microstructure. However, systematic deviations from the specific target composition were found. During subsequent heat treatment, the microstructure of the MS samples showed various degrees of grain growth and coarsening. Foils of Ti-43Al and Ti-51Al-1V fabricated by EBPVD were fully dense. The microstructures developed during EBPVD were interpreted in terms of measured phase equilibria and the dependence of evaporant flux on temperature.

  3. Use of Monocrystalline Silicon as Tool Material for Highly Accurate Blanking of Thin Metal Foils

    SciTech Connect

    Hildering, Sven; Engel, Ulf; Merklein, Marion

    2011-05-04

    The trend towards miniaturisation of metallic mass production components combined with increased component functionality is still unbroken. Manufacturing these components by forming and blanking offers economical and ecological advantages combined with the needed accuracy. The complexity of producing tools with geometries below 50 {mu}m by conventional manufacturing methods becomes disproportional higher. Expensive serial finishing operations are required to achieve an adequate surface roughness combined with accurate geometry details. A novel approach for producing such tools is the use of advanced etching technologies for monocrystalline silicon that are well-established in the microsystems technology. High-precision vertical geometries with a width down to 5 {mu}m are possible. The present study shows a novel concept using this potential for the blanking of thin copper foils with monocrystallline silicon as a tool material. A self-contained machine-tool with compact outer dimensions was designed to avoid tensile stresses in the brittle silicon punch by an accurate, careful alignment of the punch, die and metal foil. A microscopic analysis of the monocrystalline silicon punch shows appropriate properties regarding flank angle, edge geometry and surface quality for the blanking process. Using a monocrystalline silicon punch with a width of 70 {mu}m blanking experiments on as-rolled copper foils with a thickness of 20 {mu}m demonstrate the general applicability of this material for micro production processes.

  4. Permeation barrier coating and plasma sterilization of PET bottles and foils

    NASA Astrophysics Data System (ADS)

    Steves, Simon; Deilmann, Michael; Bibinov, Nikita; Awakowicz, Peter

    2009-10-01

    Modern packaging materials such as polyethylene terephthalate (PET) offer various advantages over glass or metal containers. Beside this they only offer poor barrier properties against gas permeation. Therefore, the shelf-live of packaged food is reduced. Additionally, common sterilization methods like heat, hydrogen peroxide or peracetic acid may not be applicable due to reduced heat or chemical resistance of the plastic packaging material. For the plasma sterilization and permeation barrier coating of PET bottles and foils, a microwave driven low pressure plasma reactor is developed based on a modified Plasmaline antenna. The dependencies of important plasma parameters, such as gas mixture, process pressure, power and pulse conditions on oxygen permeation through packaging foil are investigated. A residual permeation as low as J = 1.0 ±0.3 cm^3m-2day-1bar-1 for 60 nm thick silicon oxide (SiOx) coated PET foils is achieved. To discuss this residual permeation, coating defects are visualized by capacitively coupled atomic oxygen plasma etching of coated substrate. A defect density of 3000 mm-2 is revealed responsible for permeation. For plasma sterilization, optimized plasma parameters based on fundamental research of plasma sterilization mechanisms permit short treatment times of a few seconds.

  5. Concept Feasibility Report for Electroplating Zirconium onto Uranium Foil - Year 2

    SciTech Connect

    Coffey, Greg W.; Meinhardt, Kerry D.; Joshi, Vineet V.; Pederson, Larry R.; Lavender, Curt A.; Burkes, Douglas

    2015-03-01

    The Fuel Fabrication Capability within the U.S. High Performance Research Reactor Conversion Program is funded through the National Nuclear Security Administration (NNSA) NA-26 (Office of Material Management and Minimization). An investigation was commissioned to determine the feasibility of using electroplating techniques to apply a coating of zirconium onto depleted uranium/molybdenum alloy (U-10Mo). Electroplating would provide an alternative method to the existing process of hot roll-bonding zirconium foil onto the U-10Mo fuel foil during the fabrication of fuel elements for high-performance research reactors. The objective of this research was to develop a reproducible and scalable plating process that will produce a uniform, 25 μm thick zirconium metal coating on U-10Mo foil. In previous work, Pacific Northwest National Laboratory (PNNL) established a molten salt electroplating apparatus and protocol to plate zirconium metal onto molybdenum foil (Coffey 2015). During this second year of the research, PNNL furthered this work by moving to the U-10Mo alloy system (90 percent uranium:10 percent molybdenum). The original plating apparatus was disassembled and re-assembled in a laboratory capable of handling low-level radioactive materials. Initially, the work followed the previous year’s approach, and the salt bath composition was targeted at the eutectic composition (LiF:NaF:ZrF4 = 26:37:37 mol%). Early results indicated that the formation of uranium fluoride compounds would be problematic. Other salt bath compositions were investigated in order to eliminate the uranium fluoride production (LiF:NaF = 61:39 mol% and LiF:NaF:KF = 46.5:11.5:42 mol% ). Zirconium metal was used as the crucible for the molten salt. Three plating methods were used—isopotential, galvano static, and pulsed plating. The molten salt method for zirconium metal application provided high-quality plating on molybdenum in PNNL’s previous work. A key advantage of this approach is that

  6. An experimental and theoretical study of structural damping in compliant foil bearings

    NASA Technical Reports Server (NTRS)

    Ku, C.-P. Roger

    1994-01-01

    This paper describes an experimental investigation into the dynamic characteristics of corrugated foil (bump foil) strips used in compliant surface foil bearings. This study provided and opportunity to quantify the structural damping of bump foil strips. The experimental data were compared to results obtained by a theoretical model developed earlier. The effects of bearing design parameters, such as static loads, dynamic displacement amplitudes, bump configurations, pivot locations, surface coatings, and lubricant were also evaluated. An understanding of the dynamic characteristics of bump foil strips resulting from this work offers designers a means for enhancing the design of high-performance compliant foil bearings.

  7. Radio Active Waste Management: Underground Repository Method

    SciTech Connect

    Rudrapati Sandesh Kumar; Payal Shirvastava

    2002-07-01

    Finding a solution for nuclear waste is a key issue, not only for the protection of the environment but also for the future of the nuclear industry. Ten years from now, when the first decisions for the replacement of existing nuclear power plants will have to be made, The general public will require to know the solution for nuclear waste before accepting new nuclear plants. In other words, an acceptable solution for the management of nuclear waste is a prerequisite for a renewal of nuclear power. Most existing wastes are being stored in safe conditions waiting for permanent solution, with some exceptions in the former Eastern Bloc. Temporary surface or shallow storage is a well known technique widely used all over the world. A significant research effort has been made by the author of this paper in the direction of underground repository. The underground repository appears to be a good solution. Trying to transform dangerous long lived radionuclides into less harmful short lived or stable elements is a logical idea. It is indeed possible to incinerate or transmute heavy atoms of long lived elements in fast breeder reactors or even in pressurised or boiling water reactors. There are also new types of reactors which could be used, namely accelerator driven systems. High level and long lived wastes (spent fuel and vitrified waste) contain a mixture of high activity (heat producing) short lived nuclides and low activity long lived alpha emitting nuclides. To avoid any alteration due to temperature of the engineered or geological barrier surrounding the waste underground, it is necessary to store the packages on the surface for several decades (50 years or more) to allow a sufficient temperature decrease before disposing of them underground. In all cases, surface (or shallow) storage is needed as a temporary solution. This paper gives a detailed and comprehensive view of the Deep Geological Repository, providing a pragmatic picture of the means to make this method, a

  8. Plasma diagnostics for x-ray driven foils at Z

    SciTech Connect

    Heeter, R F; Bailey, J E; Cuneo, M E; Emig, J; Foord, M E; Springer, P T; Thoe, R S

    2000-06-17

    We report the development of techniques to diagnose plasmas produced by X-ray photoionization of thin foils placed near the Z-pinch on the Sandia Z Machine. The development of 100+ TW X-ray sources enables access to novel plasma regimes, such as the photoionization equilibrium. To diagnose these plasmas one must simultaneously characterize both the foil and the driving pinch. The desired photoionized plasma equilibrium is only reached transiently for a 2-ns window, placing stringent requirements on diagnostic synchronization. We have adapted existing Sandia diagnostics and fielded an additional gated 3-crystal Johann spectrometer with dual lines of sight to meet these requirements. We present sample data from experiments in which 1 cm, 180 eV tungsten pinches photoionized foils composed of 200{angstrom} Fe and 300{angstrom} NaF co-mixed and sandwiched between 1000{angstrom} layers of Lexan (CHO), and discuss the application of this work to benchmarking astrophysical models.

  9. High Temperature Performance Evaluation of a Compliant Foil Seal

    NASA Technical Reports Server (NTRS)

    Salehi, Mohsen; Heshmat, Hooshang; Walton, James F., II

    2001-01-01

    The key points to be gleaned from the effort reported herein are that the CFS (Compliant Foil Seal) has been demonstrated in conjunction with a foil bearing in a small gas turbine simulator at temperatures as high as 1000 F and outperformed a comparable brush seal. Having demonstrated the feasibility of the CFS, it would appear that this new seal design has application potential in a wide range of machines. What remains is to demonstrate performance at higher pressure ratios, consistent performance at large rotor excursions and the ability to manufacture the seal in much larger sizes exceeding by an order of magnitude that which has been tested to date.

  10. The influence of oxygen supply on metabolism of neural cells cultured on a gas-permeable PTFE foil.

    PubMed

    Mauth, Corinna; Pavlica, Sanja; Deiwick, Andrea; Steffen, Anja; Bader, Augustinus

    2010-01-01

    The influence of oxygen on neural stem cell proliferation, differentiation, and apoptosis is of great interest for regenerative therapies in neurodegenerative disorders, such as Parkinson's disease. These oxygen depending mechanisms have to been considered for the optimization of neural cell culture conditions. In this study, we used a cell culture system with an oxygen-permeable polytetrafluorethylene (PTFE) foil to investigate the effect of oxygen on metabolism and survival of neural cell lines in vitro. Human glial astrocytoma-derived cells (GOS-3) and rat pheochromacytoma cells (PC12) were cultured on the gas-permeable PTFE foil as well as a conventional non oxygen-permeable cell culture substrate at various oxygen concentrations. Analyses of metabolic activity, gene expression of apoptotic grade, and dopamine synthesis were performed. Under low oxygen partial pressure (2%, 5%) the anaerobic metabolism and apoptotic rate of cultured cells is diminished on PTFE foil when compared with the conventional culture dishes. In contrast, under higher oxygen atmosphere (21%) the number of apoptotic cells on the PTFE foil was enhanced. This culture model demonstrates a suitable model for the improvement of oxygen dependent metabolism under low oxygen conditions as well as for induction of oxidative stress by high oxygen atmosphere without supplementation of neurotoxins.

  11. Evaluation of Cadmium Ratio and Foil Activation Measurements for a Beryllium-Reflected Assembly of U(93.15)O2 Fuel Rods (1.506-cm Triangular Pitch)

    SciTech Connect

    Marshall, Margaret A.

    2014-11-04

    A series of small, compact critical assembly (SCCA) experiments were completed from 1962 to 1965 at Oak Ridge National Laboratory’s Critical Experiments Facility (ORCEF) in support of the Medium-Power Reactor Experiments (MPRE) program. Initial experiments, performed in November and December of 1962, consisted of a core of un-moderated stainless-steel tubes, each containing 26 UOIdaho National Laboratory (INL), Idaho Falls, ID (United States) fuel pellets, surrounded by a graphite reflector. Measurements were performed to determine critical reflector arrangements, fission-rate distributions, and cadmium ratio distributions. The graphite reflectors were then changed to beryllium reflectors. For the beryllium reflected assemblies, the fuel was in 1.506-cm-triangular and 7-tube clusters leading to two critical configurations. Once the critical configurations had been achieved, various measurements of reactivity, relative axial and radial activation rates of 235U, and cadmium ratios were performed. The cadmium ratio, reactivity, and activation rate measurements, performed on the 1.506-cm-array critical configuration, have been evaluated and are described in this paper.

  12. Evaluation of Cadmium Ratio and Foil Activation Measurements for a Beryllium-Reflected Assembly of U(93.15)O2 Fuel Rods (1.506-cm Triangular Pitch)

    DOE PAGES

    Marshall, Margaret A.

    2014-11-04

    A series of small, compact critical assembly (SCCA) experiments were completed from 1962 to 1965 at Oak Ridge National Laboratory’s Critical Experiments Facility (ORCEF) in support of the Medium-Power Reactor Experiments (MPRE) program. Initial experiments, performed in November and December of 1962, consisted of a core of un-moderated stainless-steel tubes, each containing 26 UOIdaho National Laboratory (INL), Idaho Falls, ID (United States) fuel pellets, surrounded by a graphite reflector. Measurements were performed to determine critical reflector arrangements, fission-rate distributions, and cadmium ratio distributions. The graphite reflectors were then changed to beryllium reflectors. For the beryllium reflected assemblies, the fuel wasmore » in 1.506-cm-triangular and 7-tube clusters leading to two critical configurations. Once the critical configurations had been achieved, various measurements of reactivity, relative axial and radial activation rates of 235U, and cadmium ratios were performed. The cadmium ratio, reactivity, and activation rate measurements, performed on the 1.506-cm-array critical configuration, have been evaluated and are described in this paper.« less

  13. Age Differences in Depth of Retrieval: Memory for Foils

    ERIC Educational Resources Information Center

    Jacoby, L.L.; Shimizu, Y.; Velanova, K.; Rhodes, M.G.

    2005-01-01

    Control over memory can be achieved in two ways: by constraining retrieval such that only sought after information comes to mind or, alternatively, by means of post-access monitoring. We used a memory-for-foils paradigm to gain evidence of differences in retrieval constraints. In this paradigm, participants studied words under deep or shallow…

  14. The Visualization of Infrared Radiation Using Thermal Sensitive Foils

    ERIC Educational Resources Information Center

    Bochnícek, Zdenek

    2013-01-01

    This paper describes a set of demonstration school experiments where infrared radiation is detected using thermal sensitive foils. The possibility of using standard glass lenses for infrared imaging is discussed in detail. It is shown that with optic components made from glass, infrared radiation up to 2.5 µm of wavelength can be detected. The…

  15. Exploding metallic foil fuse modeling at Los Alamos

    SciTech Connect

    Lindemuth, I.R.; Reinovsky, R.E.; Goforth, J.H.

    1989-01-01

    A ''first-principles'' computational model of exploding metallic foil behavior has been developed at Los Alamos. The model couples zero-dimensional magnetohydrodynamics with ohmic heating and electrical circuit equations and uses the Los Alamos SESAME atomic data base computer library to determine the foil material's temperature- and density-dependent pressure, specific energy, and electrical conductivity. The model encompasses many previously successful empirical models and offers plausible physical explanations of phenomena not treated by the empirical models. In addition to addressing the electrical circuit performance of an exploding foil, the model provides information on the temporal evolution of the foil material's density, temperature, pressure, electrical conductivity, and expansion and translational velocities. In this paper, we report the physical insight gained by computational studies of two opening switch concepts being developed for application in an FCG-driven 1-MJ-class imploding plasma z-pinch experiment. The first concept considered is a ''conventional'' electrically exploded fuse, which has been demonstrated to operate at 16 MA driven by the 15-MJ-class FCG to be used in the 1 MJ implosion experiment. The second concept considered is a Type 2 explosively formed fuse (EFF), which has been demonstrated to operate at the 8 MA level by a 1-MJ-class FCG.

  16. Tribalism as a Foiled Factor of Africa Nation-Building

    ERIC Educational Resources Information Center

    Okogu, J. O.; Umudjere, S. O.

    2016-01-01

    This paper tends to examine tribalism as a foiled factor on Africa nation-building and proffers useful tips to salvaging the Africa land from this deadly social problem. Africans in times past had suffered enormous attacks, injuries, losses, deaths, destruction of properties and human skills and ideas due to the presence of tribalistic views in…

  17. Secret in the Margins: Rutherford's Gold Foil Experiment

    ERIC Educational Resources Information Center

    Aydin, Sevgi; Hanuscin, Deborah L.

    2011-01-01

    In this article, the authors describe a lesson that uses the 5E Learning Cycle to help students not only understand the atomic model but also how Ernest Rutherford helped develop it. The lesson uses Rutherford's gold foil experiment to focus on three aspects of the nature of science: the empirical nature of science, the tentativeness of scientific…

  18. Fullurene-oxygen-iodine laser (FOIL): physical principles

    NASA Astrophysics Data System (ADS)

    Danilov, Oleg B.; Belousova, Inna M.; Mak, Artur A.; Belousov, Vlidilen P.; Grenishin, A. S.; Kiselev, V. M.; Krys'ko, A. V.; Murav'eva, T. D.; Ponomarev, Alexander N.; Sosnov, Eugene N.

    2005-03-01

    The paper considers the physical principles of developing the fullerene - oxygen - iodine laser (FOIL) with optical (sunlight in particular) pumping. Kinetic scheme of such a laser is considered. It is shown that the utmost efficiency of FOIL may exceed 40% of the energy, absorbed by fullerenes. Presented are the experimental results of singlet oxygen generation in liquid media (solutions and suspensions) and in solid-state structures, containing either fullerenes or fullerene-like nanopartickles (FNP). In experiment was shown the possibility of the singlet oxygen transfer to the gaseous phase by means of organizing of the solution (suspension) the boiling as well as of the gasodynamic wave of desorption from the solid-state structures, containing fullerenes or FNP. We present the preliminary experimental results of pulsed generation in optically pumped FOIL with the use of primary photodissociation of iodide for preparation of the atomic iodine in the generation zone. In the experiments on FOIL generation was implemented the principle of spectral separation of optical pumping.

  19. Fullerene-oxygen-iodine laser (FOIL): physical principles

    NASA Astrophysics Data System (ADS)

    Danilov, Oleg B.; Belousova, Inna M.; Mak, Artur A.; Belousov, Vlidilen P.; Grenishin, A. S.; Kiselev, V. M.; Krys'ko, A. V.; Murav'eva, T. D.; Ponomarev, Alexander N.; Sosnov, Eugene N.

    2004-06-01

    The paper considers the physical principles of developing the fullerene-oxygen-iodine laser (FOIL) with optical (sunlight in particular) pumping. Kinetic scheme of such a laser is considered. It is shown that the utmost efficiency of FOIL may exceed 40% of the energy, absorbed by fullerenes. Presented are the experimental results of singlet oxygen generation in liquid media (solutions and suspensions) and in solid-state structures, containing either fullerenes or fullerene-like nanoparticles (FNP). In experiment was shown the possibility of the singlet oxygen transfer to the gaseous phase by means of organizing of the solution (suspension) the boiling as well as of the gasodynamic wave of desorption from the solid-state structures, containing fullerenes or FNP. We present the preliminary experimental results of pulsed generation in optically pumped FOIL with the use of primary photodissociation of iodide for preparation of the atomic iodine in the generation zone. In the experiments on FOIL generation was implemented the principle of spectral separation of optical pumping.

  20. Fullerene-oxygen-iodine laser (FOIL): physical principles

    NASA Astrophysics Data System (ADS)

    Danilov, Oleg B.; Belousova, Inna M.; Mak, Artur A.; Belousov, Vlidilen P.; Grenishin, A. S.; Kiselev, V. M.; Krys'ko, A. V.; Murav'eva, T. D.; Ponomarev, Alexander N.; Sosnov, Eugene N.

    2004-09-01

    The paper considers the physical principles of developing the fullerene-oxygen-iodine laser (FOIL) with optical (sunlight in particular) pumping. Kinetic scheme of such a laser is considered. It is shown that the utmost efficiency of FOIL may exceed 40% of the energy, absorbed by fullerenes. Presented are the experimental results of singlet oxygen generation in liquid media (solutions and suspensions) and in solid-state structures, containing either fullerenes or fullerene-like nanoparticles (FNP). In experiment was shown the possibility of the singlet oxygen transfer to the gaseous phase by means of organizing of the solution (suspension) the boiling as well as of the gasodynamic wave of desorption from the solid-state structures, containing fullerenes or FNP. We present the preliminary experimental results of pulsed generation in optically pumped FOIL with the use of primary photodissociation of iodide for preparation of the atomic iodine in the generation zone. In the experiments on FOIL generation was implemented the principle of spectral separation of optical pumping.

  1. Laser-induced structure formation on stretched polymer foils

    SciTech Connect

    Bityurin, Nikita; Arnold, Nikita; Baeuerle, Dieter; Arenholz, Enno

    2007-04-15

    Noncoherent structures that develop during UV laser ablation of stretched semicrystalline polymer foils are a very general phenomenon. A thermodynamic model based on stress relaxation within the modified layer of the polymer surface describes the main features of the observed phenomena, and, in particular, the dependence of the period of structures on laser wavelength, fluence, and number of laser pulses.

  2. Large deflection analysis of a tension-foil bearing

    NASA Technical Reports Server (NTRS)

    Elrod, David A.

    1996-01-01

    The rolling element bearings (REB's) which support many turbomachinery rotors offer high load capacity, low power requirements, and durability. Two disadvantages of REB's are as follows: rolling or sliding contact within the bearing has life-limiting consequences; and REB's provide essentially no damping. The REB's in the Space Shuttle Main Engine (SSME) turbopumps must sustain high static and dynamic loads, at high speeds, with a cryogenic fluid as lubricant and coolant. The pump end ball bearings limit the life of the SSME high pressure oxygen turbopump (HPOTP). Compliant foil bearing (CFB) manufacturers have proposed replacing turbopump REB's with CFB's. CFB's work well in aircraft air cycle machines, auxiliary power units, and refrigeration compressors. In a CFB, the rotor only contacts the foil support structure during start up and shut down. CFB damping is higher than REB damping. However, the load capacity of the CFB is low, compared to a REB. Furthermore, little stiffness and damping data exist for the CFB. A rotordynamic analysis for turbomachinery critical speeds and stability requires the input of bearing stiffness and damping coefficients. The two basic types of CFB are the tension-dominated bearing and the bending-dominated bearing. Many investigators have analyzed and measured characteristics of tension-dominated foil bearings, which are applied principally in magnetic tape recording. The bending-dominated CFB is used more in rotating machinery. Recently, a new tension-foil bearing configuration has been proposed for turbomachinery applications.

  3. Using Aluminum Foil to Record Structures in Sedimentary Rock.

    ERIC Educational Resources Information Center

    Metz, Robert

    1982-01-01

    Aluminum foil can be used to make impressions of structures preserved in sedimentary rock. The impressions can be projected onto a screen, photographed, or a Plaster of Paris model can be made from them. Impressions of ripple marks, mudcracks, and raindrop impressions are provided in photographs illustrating the technique. (Author/JN)

  4. Evaluation of Alumina-Forming Austenitic Foil for Advanced Recuperators

    SciTech Connect

    Pint, Bruce A; Brady, Michael P; Yamamoto, Yukinori; Santella, Michael L; Maziasz, Philip J; Matthews, Wendy

    2011-01-01

    A corrosion- and creep-resistant austenitic stainless steel has been developed for advanced recuperator applications. By optimizing the Al and Cr contents, the alloy is fully austenitic for creep strength while allowing the formation of a chemically stable external alumina scale at temperatures up to 900 C. An alumina scale eliminates long-term problems with the formation of volatile Cr oxy-hydroxides in the presence of water vapor in exhaust gas. As a first step in producing foil for primary surface recuperators, three commercially cast heats have been rolled to 100 m thick foil in the laboratory to evaluate performance in creep and oxidation testing. Results from initial creep testing are presented at 675 C and 750 C, showing excellent creep strength compared with other candidate foil materials. Laboratory exposures in humid air at 650 800 C have shown acceptable oxidation resistance. A similar oxidation behavior was observed for sheet specimens of these alloys exposed in a modified 65 kW microturbine for 2871 h. One composition that showed superior creep and oxidation resistance has been selected for the preparation of a commercial batch of foil. DOI: 10.1115/1.4002827

  5. Foil Bearing Starting Considerations and Requirements for Rotorcraft Engine Applications

    NASA Technical Reports Server (NTRS)

    Radil, Kevin C.; DellaCorte, Christopher

    2009-01-01

    Foil gas bearings under development for rotorcraft-sized, hot core engine applications have been susceptible to damage from the slow acceleration and rates typically encountered during the pre-ignition stage in conventional engines. Recent laboratory failures have been assumed to be directly linked to operating foil bearings below their lift-off speed while following conventional startup procedures for the engines. In each instance, the continuous sliding contact between the foils and shaft was believed to thermally overload the bearing and cause the engines to fail. These failures highlight the need to characterize required acceleration rates and minimum operating speeds for these applications. In this report, startup experiments were conducted with a large, rotorcraft engine sized foil bearing under moderate load and acceleration rates to identify the proper start procedures needed to avoid bearing failure. The results showed that a bearing under a 39.4 kPa static load can withstand a modest acceleration rate of 500 rpm/s and excessive loitering below the bearing lift-off speed provided an adequate solid lubricant is present.

  6. Foil bearing performance in liquid nitrogen and liquid oxygen

    NASA Technical Reports Server (NTRS)

    Genge, Gary G.; Saville, Marshall; Gu, Alston

    1993-01-01

    Space transfer vehicles and other power and propulsion systems require long-life turbopumps. Rolling-element bearings used in current turbopumps do not have sufficient life for these applications. Process fluid foil bearings have established long life, with exceptional reliability, over a wide range of temperatures and fluids in many high-speed turbomachinery applications. However, actual data on bearing performance in cryogenic fluids has been minimal. The National Aeronautics and Space Administration (NASA) and AlliedSignal Aerospace Systems and Equipment (ASE) have attempted to characterize the leaf-type compliant foil bearing in oxygen and nitrogen. The work performed under a joint internal research and development program between Marshall Space Flight Center (MSFC) and ASE demonstrated that the foil bearing has load capacities of at least 266 psi in liquid oxygen and 352 psi in liquid nitrogen. In addition, the bearing demonstrated a direct damping coefficient of 40 to 50 lb-sec/in. with a damping ratio of .7 to 1.4 in. liquid nitrogen using a bearing sized for upper-stage turbopumps. With the results from this testing and the years of successful use in air cycle machines and other applications, leaf-type compliant foil bearings are ready for testing in liquid oxygen turbopumps.

  7. Efficient Electrochemical and Photoelectrochemical Water Splitting by a 3D Nanostructured Carbon Supported on Flexible Exfoliated Graphene Foil.

    PubMed

    Hou, Yang; Qiu, Ming; Zhang, Tao; Ma, Ji; Liu, Shaohua; Zhuang, Xiaodong; Yuan, Chris; Feng, Xinliang

    2017-01-01

    A novel 3D Co-Nx |P-complex-doped carbon grown on flexible exfoliated graphene foil is designed and constructed for both electrochemical and photoelectrochemical water splitting. The coordination of Co-Nx active centers hybridized with that of neighboring P atoms enhances the electron transfer and optimizes the charge distribution of the carbon surface, which synergistically promotes reaction kinetics by providing more exposed active sites.

  8. Non-destructive Quantitative Phase Analysis and Microstructural Characterization of Zirconium Coated U-10Mo Fuel Foils via Neutron Diffraction

    SciTech Connect

    Cummins, Dustin Ray; Vogel, Sven C.; Hollis, Kendall Jon; Brown, Donald William; Dombrowski, David E.

    2016-10-18

    This report uses neutron diffraction to investigate the crystal phase composition of uranium-molybdenum alloy foils (U-10Mo) for the CONVERT MP-1 Reactor Conversion Project, and determines the effect on alpha-uranium contamination following the deposition of a Zr metal diffusion layer by various methods: plasma spray deposition of Zr powders at LANL and hot co-rolling with Zr foils at BWXT. In summary, there is minimal decomposition of the gamma phase U-10Mo foil to alpha phase contamination following both plasma spraying and hot co-rolling. The average unit cell volume, i.e. lattice spacing, of the Zr layer can be mathematically extracted from the diffraction data; co-rolled Zr matches well with literature values of bulk Zr, while plasma sprayed Zr shows a slight increase in the lattice spacing, indicative of interstitial oxygen in the lattice. Neutron diffraction is a beneficial alternative to conventional methods of phase composition, i.e. x ray diffraction (XRD) and destructive metallography. XRD has minimal penetration depth in high atomic number materials, particularly uranium, and can only probe the first few microns of the fuel plate; neutrons pass completely through the foil, allowing for bulk analysis of the foil composition and no issues with addition of cladding layers, as in the final, aluminum-clad reactor fuel plates. Destructive metallography requires skilled technicians, cutting of the foil into small sections, hazardous etching conditions, long polishing and microscopy times, etc.; the neutron diffraction system has an automated sample loader and can fit larger foils, so there is minimal analysis preparation; the total spectrum acquisition time is ~ 1 hour per sample. The neutron diffraction results are limited by spectra refinement/calculation times and the availability of the neutron beam source. In the case of LANSCE at Los Alamos, the beam operates ~50% of the year. Following the lessons learned from these preliminary results, optimizations to

  9. Method for enhancing amidohydrolase activity of fatty acid amide hydrolase

    SciTech Connect

    John, George; Nagarajan, Subbiah; Chapman, Kent; Faure, Lionel; Koulen, Peter

    2016-10-25

    A method for enhancing amidohydrolase activity of Fatty Acid Amide Hydrolase (FAAH) is disclosed. The method comprising administering a phenoxyacylethanolamide that causes the enhanced activity. The enhanced activity can have numerous effects on biological organisms including, for example, enhancing the growth of certain seedlings. The subject matter disclosed herein relates to enhancers of amidohydrolase activity.

  10. Terahertz radiation generation by nonlinear mixing of two laser beams over a thin foil

    SciTech Connect

    Chauhan, Santosh; Parashar, J.

    2015-07-31

    Terahertz radiation generation via nonlinear mixing of two laser beams incident over a thin metal foil is explored. The lasers exert a ponderomotive force on the electrons of metal foil at beat frequency which lies in the terahertz range. The metal foil acts as antenna, producing terahertz radiations, highly directional in nature.

  11. [The taphonomic aspects of cadaverous changes in corpses, buried in the plastic foils].

    PubMed

    Stuller, F; Straka, L; Macko, V; Krivos, D; Krajcovic, J; Novomeský, F

    2008-10-01

    The forensic expertise of the 6 human bodies, being murdered in organised crime activities, had been realised by the authors. All the cadavers were packed in plastic bags or plastic foils, then buried to the illegal graves, being prepared in advance. The detail overlook and autopsy of the bodies had disclosed, that due of almost airtight sealing of the cadavers in plastic materials, the postmortal cadaverous changes went on much slower and were manifested under a different picture, as seen in the human cadavers being buried in the standard wooden coffins. The authors point out the peculiarities of such a postmortal changes, with particular focusing on the estimation of postmortal period.

  12. Tracing dynamics of laser-induced fields on ultrathin foils using complementary imaging with streak deflectometry

    NASA Astrophysics Data System (ADS)

    Abicht, F.; Braenzel, J.; Priebe, G.; Koschitzki, Ch.; Andreev, A. A.; Nickles, P. V.; Sander, W.; Schnürer, M.

    2016-09-01

    We present a detailed study of the electric and magnetic fields, which are created on plasma vacuum interfaces as a result of highly intense laser-matter interactions. For the field generation ultrathin polymer foils (30-50 nm) were irradiated with high intensity femtosecond (1019 - 1020 W /cm2 ) and picosecond (˜1017 W /cm2 ) laser pulses with ultrahigh contrast (1010 - 1011 ). To determine the temporal evolution and the spatial distribution of these fields the proton streak deflectometry method has been developed further and applied in two different imaging configurations. It enabled us to gather complementary information about the investigated field structure, in particular about the influence of different field components (parallel and normal to the target surface) and the impact of a moving ion front. The applied ultrahigh laser contrast significantly increased the reproducibility of the experiment and improved the accuracy of the imaging method. In order to explain the experimental observations, which were obtained by applying ultrashort laser pulses, two different analytical models have been studied in detail. Their ability to reproduce the streak deflectometry measurements was tested on the basis of three-dimensional particle simulations. A modification and combination of the two models allowed for an extensive and accurate reproduction of the experimental results in both imaging configurations. The controlled change of the laser pulse duration from 50 femtoseconds to 2.7 picoseconds led to a transition of the dominating force acting on the probing proton beam at the rear side of the polymer foil. In the picosecond case the (v ⇀ x B ⇀ ) -term of the Lorentz force dominated over the counteracting E ⇀-field and was responsible for the direction of the net force. The applied proton deflectometry method allowed for an unambiguous determination of the magnetic field polarity at the rear side of the ultrathin foil.

  13. CR-39 track etching and blow-up method

    DOEpatents

    Hankins, Dale E.

    1987-01-01

    This invention is a method of etching tracks in CR-39 foil to obtain uniformly sized tracks. The invention comprises a step of electrochemically etching the foil at a low frequency and a "blow-up" step of electrochemically etching the foil at a high frequency.

  14. Calibration factors for determination of relativistic particle induced fission rates in natU, 235U, 232Th, natPb and 197Au foils

    NASA Astrophysics Data System (ADS)

    Hashemi-Nezhad, S. R.; Zhuk, Igor; Potapenko, A.; Kievets, M.; Krivopustov, M. I.

    2012-02-01

    Calibration factors w, for determination of fission rate in metallic foils of natU, 235U, 232Th, natPb and 197Au were determined for foils in contact with synthetic mica track detectors. Proton-induced fission at proton energies of 0.7 GeV and 1.5 GeV were used. Using our experimental results as well as those of the other authors, w for different foil-mica systems were determined. Two methods were used to calculate w, relative to the calibration factor for uranium-mica system, which has been obtained in a standard neutron field of energy 14.7 MeV. One of these methods requires the knowledge of the mean range of the fission fragments in the foils of interest and other method needs information on the values of the fission cross-sections at the required energies as well as the density of the tracks recorded in the track detectors in contact with the foil surfaces. The obtained w-values were compared with Monte Carlo calculations and good agreements were found. It is shown that a calibration factor obtained at low energy neutron induced fissions in uranium isotopes deviates only by less than 10% from those obtained at relativistic proton induced fissions.

  15. Inactivation of possible microorganism food contaminants on packaging foils using nonthermal plasma and hydrogen peroxide

    SciTech Connect

    Scholtz, V. Khun, J.; Soušková, H.; Čeřovský, M.

    2015-07-15

    The inactivation effect of nonthermal plasma generated in electric discharge burning in air atmosphere with water or hydrogen peroxide aerosol for the application to the microbial decontamination of packaging foils is studied. The microbial inactivation is studied on two bacterial, two yeasts, and two filamentous micromycete species. The inactivation of all contaminating microorganisms becomes on the area of full 8.5 cm in diameter circular sample after short times of several tens of seconds. Described apparatus may present a possible alternative method of microbial decontamination of food packaging material or other thermolabile materials.

  16. Enhancement of ion generation in femtosecond ultraintense laser-foil interactions by defocusing

    SciTech Connect

    Xu, M. H.; Li, Y. T.; Liu, F.; Carroll, D. C.; McKenna, P.; Foster, P. S.; Hawkes, S.; Streeter, M. J. V.; Spindloe, C.; Neely, D.; Kar, S.; Markey, K.; Zepf, M.; Sheng, Z. M.; Zhang, J.; Wahlstroem, C.-G.; Zheng, J.

    2012-02-20

    A simple method to enhance ion generation with femtosecond ultraintense lasers is demonstrated experimentally by defocusing laser beams on target surface. When the laser is optimally defocused, we find that the population of medium and low energy protons from ultra-thin foils is increased significantly while the proton cutoff energy is almost unchanged. In this way, the total proton yield can be enhanced by more than 1 order, even though the peak laser intensity drops. The depression of the amplified spontaneous emission (ASE) effect and the population increase of moderate-energy electrons are believed to be the main reasons for the effective enhancement.

  17. Inactivation of possible microorganism food contaminants on packaging foils using nonthermal plasma and hydrogen peroxide

    NASA Astrophysics Data System (ADS)

    Scholtz, V.; Khun, J.; Soušková, H.; Čeřovský, M.

    2015-07-01

    The inactivation effect of nonthermal plasma generated in electric discharge burning in air atmosphere with water or hydrogen peroxide aerosol for the application to the microbial decontamination of packaging foils is studied. The microbial inactivation is studied on two bacterial, two yeasts, and two filamentous micromycete species. The inactivation of all contaminating microorganisms becomes on the area of full 8.5 cm in diameter circular sample after short times of several tens of seconds. Described apparatus may present a possible alternative method of microbial decontamination of food packaging material or other thermolabile materials.

  18. Resistively enhanced proton acceleration via high-intensity laser interactions with cold foil targets

    SciTech Connect

    Gibbon, Paul

    2005-08-01

    The acceleration of MeV protons by high-intensity laser interaction with foil targets is studied using a recently developed plasma simulation technique. Based on a hierarchical N-body tree algorithm, this method provides a natural means of treating three-dimensional, collisional transport effects hitherto neglected in conventional explicit particle-in-cell simulations. For targets with finite resistivity, hot electron transport is strongly inhibited, even at temperatures in the MeV range. This leads to suppression of ion acceleration from the rear of the target and an enhancement in energies and numbers of protons originating from the front.

  19. Thermal effects on the clearance and stiffness of foil journal bearings for a Brayton cycle turboalternator

    NASA Technical Reports Server (NTRS)

    Eshel, A.

    1972-01-01

    An analysis of foil journal bearings for a NASA Brayton Cycle Unit (BRU) is presented. The study represents an extension of previous work in that it includes the effects of thermal expansion of foil-bearing components, as well as an improved model of the influence of foil flexure. The results presented give the bearing film thickness, the bearing stiffness, and the foil tension as functions of the operating temperatures and the elasto-hydrodynamic and geometrical parameters pertinent to the design of BRU foil bearings. A computer program for the evaluation of design data and for parametric studies is included.

  20. Measurements of laser generated soft X-ray emission from irradiated gold foils

    NASA Astrophysics Data System (ADS)

    Davis, J. S.; Frank, Y.; Raicher, E.; Fraenkel, M.; Keiter, P. A.; Klein, S. R.; Drake, R. P.; Shvarts, D.

    2016-11-01

    Soft x-ray emission from laser irradiated gold foils was measured at the Omega-60 laser system using the Dante photodiode array. The foils were heated with 2 kJ, 6 ns laser pulses and foil thicknesses were varied between 0.5, 1.0, and 2.0 μm. Initial Dante analysis indicates peak emission temperatures of roughly 100 eV and 80 eV for the 0.5 μm and 1.0 μm thick foils, respectively, with little measurable emission from the 2.0 μm foils.

  1. Measurements of laser generated soft X-ray emission from irradiated gold foils

    DOE PAGES

    Davis, J. S.; Frank, Y.; Raicher, E.; ...

    2016-08-22

    We measured soft x-ray emission from laser irradiated gold foils at the Omega-60 laser system using the Dante photodiode array. The foils were heated with 2 kJ, 6ns laser pulses and foil thicknesses were varied between 0.5, 1.0, and 2.0 μm. Initial Dante analysis indicates peak emission temperatures of roughly 100 eV and 80 eV for the 0.5 μm and 1.0 μm thick foils, respectively, with little measurable emission from the 2.0 μm foils.

  2. Experimental investigation of heat transfer in a rivulet on the inclined foil

    NASA Astrophysics Data System (ADS)

    Cheverda, V. V.; Marchuk, I. V.; Karchevsky, A. L.; Orlik, E. V.; Kabov, O. A.

    2016-05-01

    Heat transfer at rivulet water flow over the constantan foil with the length of 80 mm, width of 35 mm, and thickness of 25 mm was studied experimentally. The foil surface temperature was measured by an IR-scanner. Distributions of heat flux density on the surface of the foil, where the liquid flowed, were obtained. To determine the heat flux density from the foil to liquid near the contact line, the Cauchy problem was solved for the stationary heat equation using the thermographic data. Calculation results showed that the maximal heat flux occurs in the area of the contact line and exceeds the average heat flux from the entire foil surface by several times. This is explained by the influx of heat from the periphery of foil to the rivulet due to the relatively high value of heat conductivity coefficient of the foil material and high evaporation rate in the region of the contact line.

  3. Radiation pressure acceleration of corrugated thin foils by Gaussian and super-Gaussian beams

    SciTech Connect

    Adusumilli, K.; Goyal, D.; Tripathi, V. K.

    2012-01-15

    Rayleigh-Taylor instability of radiation pressure accelerated ultrathin foils by laser having Gaussian and super-Gaussian intensity distribution is investigated using a single fluid code. The foil is allowed to have ring shaped surface ripples. The radiation pressure force on such a foil is non-uniform with finite transverse component F{sub r}; F{sub r} varies periodically with r. Subsequently, the ripple grows as the foil moves ahead along z. With a Gaussian beam, the foil acquires an overall curvature due to non-uniformity in radiation pressure and gets thinner. In the process, the ripple perturbation is considerably washed off. With super-Gaussian beam, the ripple is found to be more strongly washed out. In order to avoid transmission of the laser through the thinning foil, a criterion on the foil thickness is obtained.

  4. Quantitative Method of Measuring Metastatic Activity

    NASA Technical Reports Server (NTRS)

    Morrison, Dennis R. (Inventor)

    1999-01-01

    The metastatic potential of tumors can be evaluated by the quantitative detection of urokinase and DNA. The cell sample selected for examination is analyzed for the presence of high levels of urokinase and abnormal DNA using analytical flow cytometry and digital image analysis. Other factors such as membrane associated uroldnase, increased DNA synthesis rates and certain receptors can be used in the method for detection of potentially invasive tumors.

  5. Synthesis of Large-Sized Single-Crystal Hexagonal Boron Nitride Domains on Nickel Foils by Ion Beam Sputtering Deposition.

    PubMed

    Wang, Haolin; Zhang, Xingwang; Liu, Heng; Yin, Zhigang; Meng, Junhua; Xia, Jing; Meng, Xiang-Min; Wu, Jinliang; You, Jingbi

    2015-12-22

    Large-sized single-crystal h-BN domains with a lateral size up to 100 μm are synthesized on Ni foils by ion-beam sputtering deposition. The nucleation density of h-BN is dramatically decreased by reducing the concentrations of both active sites and species on the Ni surface through a brief in situ pretreatment of the substrate and optimization of the growth parameters, enabling the growth of large-sized domains.

  6. High-order Harmonic Generation in Ultra Thin Plasma Foil

    NASA Astrophysics Data System (ADS)

    Shuai, Bin; Shen, Baifei; Li, Ruxin; Xu, Zhizhan

    Via l-D Particle In Cell (PIC) simulations, we investigated the high-order harmonic emission from flim plasma foils irradiated by two circular- polarized, counter-propagating laser pulses with their electrical vectors rotating in different directions. More than 200 harmonics can be generated with a laser intensity of 1021 W/cm2. When the duration of laser gets shorter, the frequencies of harmonics were severely modulated due to the Doppler shift caused by the movement of the plasma boundary when the foil is being compressed. The Doppler shift can be estimated by the simulation results, and this effect can also be reduced or modified by introducing frequency chirping to the pump pulse.

  7. Plasma flow switch and foil implosion experiments on Pegasus II

    SciTech Connect

    Cochrane, J.C.; Bartsch, R.R.; Benage, J.R.; Forman, P.R.; Gribble, R.F.; Ladish, J.S.; Oona, H.; Parker, J.V.; Scudder, D.W.; Shlachter, J.S.; Wysocki, F.J.

    1993-07-01

    Pegasus II is the upgraded version of Pegasus, a pulsed power machine used in the Los Alamos AGEX (Above Ground EXperiments) program. A goal of the program is to produce an intense (> 100 TW) source of soft x-rays from the thermalization of the kinetic energy of a 1 to 10 MJ plasma implosion. The radiation pulse should have a maximum duration of several 10`s of nanoseconds and will be used in the study of fusion conditions and material properties. The radiating plasma source will be generated by the thermalization of the kinetic energy of an imploding cylindrical, thin, metallic foil. This paper addresses experiments done on a capacitor bank to develop a switch (plasma flow switch) to switch the bank current into the load at peak current. This allows efficient coupling of bank energy into foil kinetic energy.

  8. Direct drive foil implosion experiments on Pegasus II

    SciTech Connect

    Cochrane, J.C.; Bartsch, R.R.; Benage, J.F.; Forman, P.R.; Gribble, R.F.; Hockaday, M.Y.P.; Hockaday, R.G.; Ladish, J.S.; Oona, H.; Parker, J.V.; Shlachter, J.S.; Wysocki, F.J.

    1993-05-01

    Pegasus II is the upgraded version of Pegasus, a pulsed power machine used in the Los Alamos Above Ground Experiments (AGEX) program. The goal of the program is to produce an intense (>100 TW) source of soft x-rays from the thermalization of the KE of a 1 to 10 MJ collapsing plasma source. The radiation pulse should have a maximum duration of several tens of nanoseconds and will be used in the study of fusion conditions and material properties. This paper addresses z-pinch experiments done on a capacitor bank where the radiating plasma source is formed by an imploding annular aluminum foil driven by the J {times} B forces generated by the current flowing through the foil.

  9. Plasma flow switch and foil implosion experiments on Pegasus II

    SciTech Connect

    Cochrane, J.C.; Bartsch, R.R.; Benage, J.R.; Forman, P.R.; Gribble, R.F.; Ladish, J.S.; Oona, H.; Parker, J.V.; Scudder, D.W.; Shlachter, J.S.; Wysocki, F.J.

    1993-01-01

    Pegasus II is the upgraded version of Pegasus, a pulsed power machine used in the Los Alamos AGEX (Above Ground EXperiments) program. A goal of the program is to produce an intense (> 100 TW) source of soft x-rays from the thermalization of the kinetic energy of a 1 to 10 MJ plasma implosion. The radiation pulse should have a maximum duration of several 10's of nanoseconds and will be used in the study of fusion conditions and material properties. The radiating plasma source will be generated by the thermalization of the kinetic energy of an imploding cylindrical, thin, metallic foil. This paper addresses experiments done on a capacitor bank to develop a switch (plasma flow switch) to switch the bank current into the load at peak current. This allows efficient coupling of bank energy into foil kinetic energy.

  10. CHARACTERIZATION OF MONOLITHIC FUEL FOIL PROPERTIES AND BOND STRENGTH

    SciTech Connect

    D E Burkes; D D Keiser; D M Wachs; J S Larson; M D Chapple

    2007-03-01

    Understanding fuel foil mechanical properties, and fuel / cladding bond quality and strength in monolithic plates is an important area of investigation and quantification. Specifically, what constitutes an acceptable monolithic fuel – cladding bond, how are the properties of the bond measured and determined, and what is the impact of fabrication process or change in parameters on the level of bonding? Currently, non-bond areas are quantified employing ultrasonic determinations that are challenging to interpret and understand in terms of irradiation impact. Thus, determining mechanical properties of the fuel foil and what constitutes fuel / cladding non-bonds is essential to successful qualification of monolithic fuel plates. Capabilities and tests related to determination of these properties have been implemented at the INL and are discussed, along with preliminary results.

  11. Determination of integral cross sections of 3 H in Al foils monitors irradiated by protons with energies ranging from 40 to 2600 MeV

    DOE PAGES

    Titarenko, Yu. E.; Batyaev, V. F.; Chauzova, M. V.; ...

    2016-01-01

    Our results of 3H production in Al foil monitors (~ 59 mg/cm2 thickness) are presented. We irradiated these foils in 15×15 mm polyethylene bags of ~ 14 mg/cm2 thickness together with foils of Cr (~ 395 mg/cm2 thickness) and 56Fe (~ 332 mg/cm2 thickness) by protons of different energies in a range of 0.04 – 2.6 GeV. The diameters of all the foils were 10.5 mm. The irradiations were carried out at the ITEP accelerator U–10 under the ISTC Project # 3266 in 2006–2009. 3H has been extracted from Al foils using an A307 Sample Oxidizer. We then used anmore » ultra low level liquid scintillation spectrometer Quantulus1220 to measure the 3H β–spectra and the SpectraDec software package was applied for spectra processing, deconvolution and 3H activity determination. The values of the Al (p, x)3H reaction cross sections obtained in these experiments are compared with data measured at other labs and with results of simulations by the MCNP6 radiation transport code using the CEM03.03 event generator.« less

  12. Determination of integral cross sections of 3 H in Al foils monitors irradiated by protons with energies ranging from 40 to 2600 MeV

    SciTech Connect

    Titarenko, Yu. E.; Batyaev, V. F.; Chauzova, M. V.; Chauzova, M. V.; Kashirin, I. A.; Malinovskiy, S. V.; Pavlov, K. V.; Rogov, V. I.; Titarenko, A. Yu.; Zhivun, V. M.; Mashnik, S. G.; Stankovskiy, A. Yu.

    2016-01-01

    Our results of 3H production in Al foil monitors (~ 59 mg/cm2 thickness) are presented. We irradiated these foils in 15×15 mm polyethylene bags of ~ 14 mg/cm2 thickness together with foils of Cr (~ 395 mg/cm2 thickness) and 56Fe (~ 332 mg/cm2 thickness) by protons of different energies in a range of 0.04 – 2.6 GeV. The diameters of all the foils were 10.5 mm. The irradiations were carried out at the ITEP accelerator U–10 under the ISTC Project # 3266 in 2006–2009. 3H has been extracted from Al foils using an A307 Sample Oxidizer. We then used an ultra low level liquid scintillation spectrometer Quantulus1220 to measure the 3H β–spectra and the SpectraDec software package was applied for spectra processing, deconvolution and 3H activity determination. The values of the Al (p, x)3H reaction cross sections obtained in these experiments are compared with data measured at other labs and with results of simulations by the MCNP6 radiation transport code using the CEM03.03 event generator.

  13. Noninvasive Monitoring of Arterial Viscoelastic Indices Using a Foil-type Pressure Sensor

    NASA Astrophysics Data System (ADS)

    Maruyama, Hiromi; Hirano, Harutoyo; Kutluk, Abdugheni; Tsuji, Toshio; Fukuda, Osamu; Ueno, Naohiro; Ukawa, Teiji; Nakamura, Ryuji; Saeki, Noboru; Kawamoto, Masashi; Yoshizumi, Masao

    This paper proposes a noninvasive method for estimating the dynamic characteristics of arterial walls using pulse waves measured in various parts of the body by a foil-type pressure sensor. The sensor not only has high sensitivity and flexibility but also features the ability to continuously measure the alternating-current component of pulse waves. These capabilities make it suitable for estimating the dynamic characteristics of arterial walls. In this paper, a foil-type pressure sensor was employed to measure pulse waves based on the tonometry approach, and a method of estimating changes in arterial viscoelastic indices was proposed based on the measured pulse waves and photoplethysmograms. In order to accurately measure blood pressure, first, we examined suitable mechanical forces to the sensor, and found that values of 5-25[N] yielded the best performance. We then estimated the arterial viscoelastic indices of a radial artery and a dorsal pedis artery when mechanical pain stimuli were applied to the subjects. The results suggested that the estimated indices can be used to quantitatively assess vascular response caused by sympathicotonia. We thus concluded that the proposed method enabled noninvasive measurement of pulse waves in the dorsal pedis artery and estimation of arterial viscoelastic indices.

  14. Fine plastic foil as backing for sputtered nickel targets.

    PubMed

    Stolarz, Anna; Seppälä, Raimo

    Targets of (58)Ni and (60)Ni with areal density between 71 and 105 μg/cm(2) backed with polyimide foil of 35-40 μg/cm(2) were prepared by sputtering with Ar ions produced by a home made sputtering device at the Target Laboratory, University of Jyväskylä. The efficiency of the procedure was about 20 %.

  15. Hot Rolling of Gamma Titanium Aluminide Foil (PREPRINT)

    DTIC Science & Technology

    2010-04-01

    the flow stress as a function of strain rate , the strength coefficient for the specific phase i, 10 and the strain - rate sensitivity (assumed to...extended to the case of rate - sensitive , incompressible materials by Suquet [14]. Subsequently, it was applied to conventional titanium alloys by...AFRL-RX-WP-TP-2010-4138 HOT ROLLING OF GAMMA TITANIUM ALUMINIDE FOIL (PREPRINT) S.L. Semiatin Metals Branch Metals, Ceramics & NDE

  16. Nickel foil microcantilevers for magnetic manipulation and localized heating.

    PubMed

    Gaitas, Angelo; McNaughton, Brandon H

    2013-12-01

    Cellular manipulation has been investigated by a number of techniques. In this manuscript nickel foil microcantilevers were used for magnetophoresis and manipulation of microparticles and magnetically labeled HeLa cells. The cantilevers were also used for localized heating in liquid, reaching biologically relevant temperatures. This work aims to develop cantilevers for sample enrichment, manipulation, and thermal applications, offering an inexpensive and versatile solution compatible with standard tools in research and clinical diagnostic testing, such as microwell plates.

  17. Nickel foil microcantilevers for magnetic manipulation and localized heating

    PubMed Central

    Gaitas, Angelo; McNaughton, Brandon H.

    2014-01-01

    Cellular manipulation has been investigated by a number of techniques. In this manuscript nickel foil microcantilevers were used for magnetophoresis and manipulation of microparticles and magnetically labeled HeLa cells. The cantilevers were also used for localized heating in liquid, reaching biologically relevant temperatures. This work aims to develop cantilevers for sample enrichment, manipulation, and thermal applications, offering an inexpensive and versatile solution compatible with standard tools in research and clinical diagnostic testing, such as microwell plates. PMID:25541581

  18. Investigation of the clinical potential of scattering foil free electron beams

    NASA Astrophysics Data System (ADS)

    Eldib, Ahmed; Jin, Lihui; Li, Jinsheng; Ma, C.-M. Charlie

    2014-02-01

    Electron beam therapy has been an important radiation therapy modality for many decades. Studies have been conducted recently for more efficient and advanced delivery of electron beam radiation therapy. X-ray contamination is a common problem that exists with all of the advanced electron beam therapy techniques such as Bolus Electron conformal therapy, segmented electron conformal therapy, and modulated electron arc therapy. X-ray contamination could add some limitations to the advancement and clinical utility of those electron modalities. It was previously shown in the literature that the scattering foil is one of the major accelerator parts contributing to the generation of bremsstrahlung photons. Thus, in this work we investigate the dosimetric characteristics of scattering foil free (SFF) electron beams and the feasibility of using those beams for breast cancer boosts. The SFF electron beams were modeled and simulated using the Monte Carlo method. CT scans of six previously treated breast patients were used for the treatment plan generation utilizing our in-house Monte Carlo-based treatment planning system. Electron boost plans with conventional beams and the SFF beams were generated, respectively, for all patients. A significant reduction of the photon component was observed with the removal of the primary scattering foil for beam energies higher than 12 MeV. Flatness was greatly affected but the difference in flatness between conventional and SFF beams was much reduced for small cone sizes, which were often used clinically for breast boosts. It was found that the SFF electron beams could deliver high-quality dose distributions as conventional electron beams for boost treatments of the breast with an added advantage of a further reduced dose to the lung and the heart.

  19. Investigation of the clinical potential of scattering foil free electron beams.

    PubMed

    Eldib, Ahmed; Jin, Lihui; Li, Jinsheng; Ma, C-M Charlie

    2014-02-21

    Electron beam therapy has been an important radiation therapy modality for many decades. Studies have been conducted recently for more efficient and advanced delivery of electron beam radiation therapy. X-ray contamination is a common problem that exists with all of the advanced electron beam therapy techniques such as Bolus Electron conformal therapy, segmented electron conformal therapy, and modulated electron arc therapy. X-ray contamination could add some limitations to the advancement and clinical utility of those electron modalities. It was previously shown in the literature that the scattering foil is one of the major accelerator parts contributing to the generation of bremsstrahlung photons. Thus, in this work we investigate the dosimetric characteristics of scattering foil free (SFF) electron beams and the feasibility of using those beams for breast cancer boosts. The SFF electron beams were modeled and simulated using the Monte Carlo method. CT scans of six previously treated breast patients were used for the treatment plan generation utilizing our in-house Monte Carlo-based treatment planning system. Electron boost plans with conventional beams and the SFF beams were generated, respectively, for all patients. A significant reduction of the photon component was observed with the removal of the primary scattering foil for beam energies higher than 12 MeV. Flatness was greatly affected but the difference in flatness between conventional and SFF beams was much reduced for small cone sizes, which were often used clinically for breast boosts. It was found that the SFF electron beams could deliver high-quality dose distributions as conventional electron beams for boost treatments of the breast with an added advantage of a further reduced dose to the lung and the heart.

  20. Density Profile of a Foil Accelerated by Laser Ablation

    NASA Astrophysics Data System (ADS)

    Knauer, J. P.; Hu, S. X.; Goncharov, V. N.; Haberberger, D.

    2016-10-01

    An experiment to measure the density profile of a foil accelerated by laser ablation has been designed and is underway. High-density material is measured with x-ray radiography and low-density plasma is measured using 251-nm interferometry. Two-dimensional hydrodynamic simulation results from the code DRACO will be compared to these data. The accelerated foil is an 80- μm-thick CH target with Ge and Si-doped layers. The incident laser is a 351-nm, 5-ns pulse with a total energy of 6.2 kJ. Si and Ti x rays are used for the radiography measurement. A 1-D image versus time data are recorded with an x-ray streak camera and 2-D image data at specific times are recorded with an x-ray framing camera using point-projection backlighting. Foil acceleration is measured with the 1-D data. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  1. Flapping propulsion with side-by-side pitching foils

    NASA Astrophysics Data System (ADS)

    Huera-Huarte, Francisco

    2016-11-01

    Fish schools are one of the most common types of collective behaviour observed in nature. One of the reasons why fish swim in groups, is to reduce the cost of transport of the school. In this work we explore the propulsive performance of two foils flapping in a symmetric configuration, i.e. with an out-of-phase flapping motion. Direct thrust measurements and Particle Image Velocimetry (PIV) allowed a detailed examination of the forces and the wake generated by the system, for different kinematics (swept angles and frequencies) and shaft separations. For certain specific cases, volumetric PIV shows major differences on how the different structures in the wake of the system evolve, depending on the imposed kinematics and the side-by-side separation between the foils. Results obtained will be compared against data produced with isolated flapping foils with similar imposed kinematics, with the aim to better understand the interactions between both and the performance of the system as a whole. The author would like to acknowledge the financial support provided by the Spanish Ministerio de Economia y competitividad (MINECO) through Grant DPI2015-71645-P.

  2. Comparison of EXAFS Foil Spectra from Around the World

    SciTech Connect

    Kelly, S. D.; Bare, S. R.; Greenlay, N.; Azevedo, G.; Balasubramanian, M.; Barton, D.; Chattopadhyay, S.; Fakra, S.; Johannessen, B.; Newville, M.; Pena, J.; Pokrovski, G. S; Proux, O.; Priolkar, K.; Ravel, B.; Webb, S. M.

    2010-07-16

    The EXAFS spectra of Cu and Pd foil from many different beamlines and synchrotrons are compared to address the dependence of the amplitude reduction factor (S{sub 0}{sup 2}) on beamline specific parameters. Even though S{sub 0}{sup 2} is the same parameter as the EXAFS coordination number, the value for S{sub 0}{sup 2} is given little attention, and is often unreported. The S{sub 0}{sup 2} often differs for the same material due to beamline and sample attributes, such that no importance is given to S{sub 0}{sup 2}-values within a general range of 0.7 to 1.1. EXAFS beamlines have evolved such that it should now be feasible to use standard S{sub 0}{sup 2} values for all EXAFS measurements of a specific elemental environment. This would allow for the determination of the imaginary energy (Ei) to account for broadening of the EXAFS signal rather than folding these errors into an effective S{sub 0}{sup 2}-value. To test this concept, we model 11 Cu-foil and 6 Pd-foil EXAFS spectra from around the world to compare the difference in S{sub 0}{sup 2}- and Ei-values.

  3. Active magnetic regenerator method and apparatus

    DOEpatents

    DeGregoria, Anthony J.; Zimm, Carl B.; Janda, Dennis J.; Lubasz, Richard A.; Jastrab, Alexander G.; Johnson, Joseph W.; Ludeman, Evan M.

    1993-01-01

    In an active magnetic regenerator apparatus having a regenerator bed of material exhibiting the magnetocaloric effect, flow of heat transfer fluid through the bed is unbalanced, so that more fluid flows through the bed from the hot side of the bed to the cold side than from the cold side to the hot side. The excess heat transfer fluid is diverted back to the hot side of the bed. The diverted fluid may be passed through a heat exchanger to draw heat from a fluid to be cooled. The apparatus may be operated at cryogenic temperatures, and the heat transfer fluid may be helium gas and the fluid to be cooled may be hydrogen gas, which is liquified by the device. The apparatus can be formed in multiple stages to allow a greater span of cooling temperatures than a single stage, and each stage may be comprised of two bed parts. Where two bed parts are employed in each stage, a portion of the fluid passing from the hot side to the cold side of a first bed part which does not have a magnetic field applied thereto is diverted back to the cold side of the other bed part in the stage, where it is passed through to the hot side. The remainder of the fluid from the cold side of the bed part of the first stage is passed to the hot side of the bed part of the second stage.

  4. The surface condition effect of Cu2O flower/grass-like nanoarchitectures grown on Cu foil and Cu film

    PubMed Central

    2013-01-01

    Cu2O flower/grass-like nanoarchitectures (FGLNAs) were fabricated directly on two category specimens of Cu foils and Cu film using thermal oxidation method. The FGLNAs are approximately 3.5 to 12 μm in size, and their petals are approximately 50 to 950 nm in width. The high compressive stress caused by a large oxide volume in the Cu2O layer on the specimen surface played an important role in the growth of FGLNAs. The effects of surface conditions, such as the surface stresses, grain size, and surface roughness of Cu foil and Cu film specimens, on the FGLNA growth were discussed in detail. PACS 81. Materials science; 81.07.-b Nanoscale materials and structures: fabrication and characterization; 81.16.Hc Catalytic methods PMID:24164860

  5. Comparison of bond strength between simple foil mesh and laser-structured base retention brackets.

    PubMed

    Sorel, Olivier; El Alam, Rafeh; Chagneau, Francis; Cathelineau, Guy

    2002-09-01

    The aims of the current study were to evaluate the bond strength of a new metallic orthodontic bracket with a laser structured base (Discovery, Dentaurum, Ispringen, Germany), and its effects on the site of bond failure and on the behavior of the enamel after debonding. One hundred and twenty recently extracted human premolars were bonded with 1 of 2 types of mechanical interlock base metal brackets: a standard system with a simple foil mesh pad (Minitrim, Dentaurum) and the Discovery bracket. A resin-based, chemically activated bonding system, No-mix (Dentaurum), was used as the adhesive system in this trial. The teeth were immersed in normal saline solution at 37 degrees C for 7 days before debonding and were randomly assigned to different subgroups. A testing machine was used to evaluate tensile and fatigue bond strengths for both brackets. After debonding, the amount of residual adhesive on the bracket and enamel detachment were assessed according to the adhesive remnant index (ARI) and the enamel detachment index (EDI) with a scanning electron microscope and an energy dispersive X-ray spectrometer. The scores obtained from the ARI and the EDI showed that the laser structured base brackets had a significantly higher bond strength (mean +/- SD: 17.1 +/- 0.7 MPa) that was 2 times higher than that observed with the simple foil mesh brackets (mean +/- SD: 8.7 +/- 1.4 MPa) (P <.001). Bond failure with the laser structured base was at the enamel-adhesive interface with an ARI score of 3 in 80% of the teeth, and bond failure with the simple foil mesh base was at the bracket-adhesive interface with an ARI score of 0 in 75% of the teeth. A small area, with less than 10% of the enamel damaged (1 on the EDI) and 1.5 microm in thickness, was observed for both brackets. The laser structured base bracket's bond strength was double that of the simple foil mesh bracket but was equally safe and did not induce significant enamel detachment.

  6. Consideration of Alternate Working Fluid Properties in Gas Lubricated Foil Journal Bearings

    NASA Technical Reports Server (NTRS)

    Smith, Matthew J.

    2004-01-01

    The Oil-Free Turbomachinery Program at the NASA Glenn Research center is committed to, revolutionary improvements in performance, efficiency and reliability of turbomachinery propulsion systems. One of the key breakthroughs by which this goal is being achieved is the maturation of air lubricated foil bearing technology. Through experimental testing, foil bearings have demonstrated a variety of exceptional qualities that show them to have an important role in the future of rotordynamic lubrication. Most of the work done with foil bearings thus far has considered ambient air at atmospheric pressure as the working fluid or lubricating fluid in the bearing. However, special applications of oil-free technology require the use of air at non- standard ambient conditions or completely different working fluids altogether. The NASA Jupiter Icy Moon Orbiter program presents power generation needs far beyond that of any previous space exploration effort. The proposed spacecraft will require significant power generation to provide the propulsion necessary to reach the moons of Jupiter and navigate between them. Once there, extensive scientific research will be conducted that will also present significant power requirements. Such extreme needs require exploring a new method for power generation in space. A proposed solution involves a Brayton cycle nuclear fission reactor. The nature of this application requires reliable performance of all reactor components for many years of operation under demanding conditions. This includes the bearings which will be operating with an alternative working fluid that is a combination of Helium and Xenon gases commonly known as HeXe. This fluid has transport and thermal properties that vary significantly from that of air and the effect of these property differences on bearing performance must be considered. One of the most promising applications of oil-free technology is in aircraft turbine engines. Eliminating the oil supply systems from

  7. The effects of passive foil flexibility on the energy extraction performance of an oscillating foil operating at low reduced frequencies

    NASA Astrophysics Data System (ADS)

    Totpal, Alexander D.; Siala, Firas F.; Liburdy, James A.

    2016-11-01

    With a goal to improve energy extraction efficiency from an oscillating foil, direct aerodynamic force measurements are used to study the effect of surface flexibility of an oscillating foil operating in the energy harvesting regime. The experiments are conducted in a closed-loop wind tunnel at a low reduced frequencies range of 0.04-0.06. The pitching amplitude was varied from 45 to 90 degrees and the phase shift between pitching and heaving motions was varied from 30 to 120 degrees. Three different airfoil configurations were tested: fully rigid, flexible leading edge and flexible trailing edge. In addition, phase-locked particle image velocimetry (PIV) measurements were taken at the higher efficiency cases, and are used to help interpret trends seen in the force measurement data. The timing and position of the leading edge vortex along the foil, which has been shown to be crucial to energy extraction, is investigated in order to help explain why certain operating conditions yield larger efficiencies.

  8. Analytical Scanning and Transmission Electron Microscopy of Laboratory Impacts on Stardust Aluminium Foils: Interpreting Impact Crater Morphology and the Composition of Impact Residues.

    SciTech Connect

    Kearsley, A T; Graham, G A; Burchell, M J; Cole, M J; Dai, Z R; Teslich, N; Chater, R; Wozniakiewicz, P A; Spratt, J; Jones, G

    2006-10-19

    The known encounter velocity (6.1kms{sup -1}) between the Stardust spacecraft and the dust emanating from the nucleus of comet Wild 2 has allowed realistic simulation of dust collection in laboratory experiments designed to validate analytical methods for the interpretation of dust impacts on the aluminium foil components of the Stardust collector. In this report we present information on crater gross morphology, the pre-existing major and trace element composition of the foil, geometrical issues for energy dispersive X-ray analysis of the impact residues in scanning electron microscopes, and the modification of dust chemical composition during creation of impact craters as revealed by analytical transmission electron microscopy. Together, these observations help to underpin the interpretation of size, density and composition for particles impacted upon the Stardust aluminium foils.

  9. Stability of rigid rotors supported by air foil bearings: Comparison of two fundamental approaches

    NASA Astrophysics Data System (ADS)

    Larsen, Jon S.; Santos, Ilmar F.; von Osmanski, Sebastian

    2016-10-01

    High speed direct drive motors enable the use of Air Foil Bearings (AFB) in a wide range of applications due to the elimination of gear forces. Unfortunately, AFB supported rotors are lightly damped, and an accurate prediction of their Onset Speed of Instability (OSI) is therefore important. This paper compares two fundamental methods for predicting the OSI. One is based on a nonlinear time domain simulation and another is based on a linearised frequency domain method and a perturbation of the Reynolds equation. Both methods are based on equivalent models and should predict similar results. Significant discrepancies are observed leading to the question, is the classical frequency domain method sufficiently accurate? The discrepancies and possible explanations are discussed in detail.

  10. The Reality-Based Learning Method: A Simple Method for Keeping Teaching Activities Relevant and Effective

    ERIC Educational Resources Information Center

    Smith, Louise W.; Van Doren, Doris C.

    2004-01-01

    Active and experiential learning theory have not dramatically changed collegiate classroom teaching methods, although they have long been included in the pedagogical literature. This article presents an evolved method, reality based learning, that aids professors in including active learning activities with feelings of clarity and confidence. The…

  11. A Simple and Accurate Method for Measuring Enzyme Activity.

    ERIC Educational Resources Information Center

    Yip, Din-Yan

    1997-01-01

    Presents methods commonly used for investigating enzyme activity using catalase and presents a new method for measuring catalase activity that is more reliable and accurate. Provides results that are readily reproduced and quantified. Can also be used for investigations of enzyme properties such as the effects of temperature, pH, inhibitors,…

  12. In situ synthesis of Cu2O and Cu nanoparticles during the thermal reduction of copper foil-supported graphene oxide

    NASA Astrophysics Data System (ADS)

    Ortega-Amaya, R.; Matsumoto, Y.; Pérez-Guzmán, M. A.; Ortega-López, M.

    2015-10-01

    This work describes a novel method to prepare reduced graphene oxide (rGO) sheets decorated with copper oxide and copper nanoparticles, by annealing copper foil-supported graphene oxide (GO) under an Ar atmosphere. The GO reduction level, the predominant Cu or Cu2O compound, and the particle size strongly depend on the process temperature. Scanning electron microscopy and X-ray diffraction analysis revealed that rGO-Cu2O and rGO-Cu nanocomposites developed on the Cu foil surface at the annealing temperatures of 200-600 and 800-1000 °C range, respectively. Raman spectroscopy corroborates the effective GO reduction.

  13. Highly efficient growth of vertically aligned carbon nanotubes on Fe-Ni based metal alloy foils for supercapacitors

    NASA Astrophysics Data System (ADS)

    Amalina Raja Seman, Raja Noor; Asyadi Azam, Mohd; Ambri Mohamed, Mohd

    2016-12-01

    Supercapacitors are highly promising energy devices with superior charge storage performance and a long lifecycle. Construction of the supercapacitor cell, especially electrode fabrication, is critical to ensure good performance in applications. This work demonstrates direct growth of vertically aligned carbon nanotubes (CNTs) on Fe-Ni based metal alloy foils, namely SUS 310S, Inconel 600 and YEF 50, and their use in symmetric vertically aligned CNT supercapacitor electrodes. Alumina and cobalt thin film catalysts were deposited onto the foils, and then CNT growth was performed using alcohol catalytic chemical vapour deposition. By this method, vertically aligned CNTs were successfully grown and used directly as a binder-free supercapacitor electrode to deliver excellent electrochemical performance. The device showed relatively good specific capacitance, a superior rate capability and excellent cycle stability, maintaining about 96% capacitance up to 1000 cycles.

  14. Combined synchrotron X-ray tomography and X-ray powder diffraction using a fluorescing metal foil.

    PubMed

    Kappen, P; Arhatari, B D; Luu, M B; Balaur, E; Caradoc-Davies, T

    2013-06-01

    This study realizes the concept of simultaneous micro-X-ray computed tomography and X-ray powder diffraction using a synchrotron beamline. A thin zinc metal foil was placed in the primary, monochromatic synchrotron beam to generate a divergent wave to propagate through the samples of interest onto a CCD detector for tomographic imaging, thus removing the need for large beam illumination and high spatial resolution detection. Both low density materials (kapton tubing and a piece of plant) and higher density materials (Egyptian faience) were investigated, and elemental contrast was explored for the example of Cu and Ni meshes. The viability of parallel powder diffraction using the direct beam transmitted through the foil was demonstrated. The outcomes of this study enable further development of the technique towards in situ tomography∕diffraction studies combining micrometer and crystallographic length scales, and towards elemental contrast imaging and reconstruction methods using well defined fluorescence outputs from combinations of known fluorescence targets (elements).

  15. Combined synchrotron X-ray tomography and X-ray powder diffraction using a fluorescing metal foil

    NASA Astrophysics Data System (ADS)

    Kappen, P.; Arhatari, B. D.; Luu, M. B.; Balaur, E.; Caradoc-Davies, T.

    2013-06-01

    This study realizes the concept of simultaneous micro-X-ray computed tomography and X-ray powder diffraction using a synchrotron beamline. A thin zinc metal foil was placed in the primary, monochromatic synchrotron beam to generate a divergent wave to propagate through the samples of interest onto a CCD detector for tomographic imaging, thus removing the need for large beam illumination and high spatial resolution detection. Both low density materials (kapton tubing and a piece of plant) and higher density materials (Egyptian faience) were investigated, and elemental contrast was explored for the example of Cu and Ni meshes. The viability of parallel powder diffraction using the direct beam transmitted through the foil was demonstrated. The outcomes of this study enable further development of the technique towards in situ tomography/diffraction studies combining micrometer and crystallographic length scales, and towards elemental contrast imaging and reconstruction methods using well defined fluorescence outputs from combinations of known fluorescence targets (elements).

  16. Surface plasmon resonance induced excellent solar control for VO₂@SiO₂ nanorods-based thermochromic foils.

    PubMed

    Zhou, Yijie; Huang, Aibin; Li, Yamei; Ji, Shidong; Gao, Yanfeng; Jin, Ping

    2013-10-07

    Transition-metal oxide nanocrystals are novel candidates for being used as the hosts of localized surface plasmon resonance because they exhibit fascinating properties arising from the unique characteristics of their outer-d valence electrons. VO₂(M) nanocrystal is well-known due to its reversible metal-insulator transition (MIT) temperature near room temperature (∼68 °C) corresponding to the appearance/disappearance of localized surface plasmon resonance across the MIT. In this study, a microemulsion-based method was introduced to synthesize VO₂(M)@SiO₂ nanoparticles which were applied to prepare VO₂-based thermochromic foils owing to a strong and tunable surface plasmon resonance in the metallic state. The optical transmittance spectra demonstrates that the employment of surface plasmon resonance in VO₂-based thermochromic foils greatly improves their solar regulating efficiency up to 18.54%, and provides an unprecedented insight in optimizing VO₂-based thermochromic windows for solar control.

  17. Growth and composition of nanostructured and nanoporous cerium oxide thin films on a graphite foil.

    PubMed

    Lavkova, Jaroslava; Khalakhan, Ivan; Chundak, Mykhailo; Vorokhta, Mykhailo; Potin, Valerie; Matolin, Vladimir; Matolinova, Iva

    2015-03-07

    The morphology and composition of CeOx films prepared by r.f. magnetron sputtering on a graphite foil have been investigated mainly by using microscopy methods. This study presents the formation of nanocrystalline layers with porous structure due to the modification of a carbon support and the formation of cerium carbide crystallites as a result of the deposition process. Chemical analyses of the layers with different thicknesses performed by energy dispersive X-ray spectroscopy, electron energy loss spectroscopy and X-ray photoelectron spectroscopy have pointed to the reduction of the cerium oxide layers. In the deposited layers, cerium was present in mixed Ce(3+) and Ce(4+) valence. Ce(3+) species were located mainly at the graphite foil-CeOx interface and the chemical state of cerium was gradually changing to Ce(4+) going to the layer surface. It became more stoichiometric in the case of thicker layers except for the surface region, where the presence of Ce(3+) was associated with oxygen vacancies on the surface of cerium oxide grains. The degree of cerium oxide reduction is discussed in the context of particle size.

  18. Structural stiffness and Coulomb damping in compliant foil journal bearings: Parametric studies

    NASA Astrophysics Data System (ADS)

    Ku, C.-P. Roger; Heshmat, Hooshang

    1994-07-01

    This paper presents the results of the second part of the investigation on structural stiffness and Coulomb damping in compliant foil journal bearings. In the first part, a theoretical model was developed to calculate equivalent viscous damping coefficients and structural stiffness of a bump foil strip in a journal bearing or damper. A computer program was also developed to compute the eccentricity and attitude angle of the journal static equilibrium position as well as the deflections, displacements, reacting forces, and equivalent friction coefficient of each bump on the strip. This model and program enabled further parametric studies to be conducted in the second part of the investigation, the results of which are the subject of this paper. The design parameters studied were static eccentricity (bearing load), pad angle (load angle), sliding friction coefficients, and perturbation amplitude (dynamic load). In addition, more effective methods of achieving both Coulomb damping and optimum structural stiffness were examined. The results of the studies showed that stiffness and damping coefficients were highly nonlinear and anisotropic, that their values depended on the sums of the sliding friction coefficients between contact surfaces, and that they were greatly affected by the pad angle.

  19. The efficient computation of the nonlinear dynamic response of a foil-air bearing rotor system

    NASA Astrophysics Data System (ADS)

    Bonello, P.; Pham, H. M.

    2014-07-01

    The foil-air bearing (FAB) enables the emergence of oil-free turbomachinery. However, its potential to introduce undesirable nonlinear effects necessitates a reliable means for calculating the dynamic response. The computational burden has hitherto been alleviated by simplifications that compromised the true nature of the dynamic interaction between the rotor, air film and foil structure, introducing the potential for significant error. The overall novel contribution of this research is the development of efficient algorithms for the simultaneous solution of the state equations. The equations are extracted using two alternative transformations: (i) Finite Difference (FD); and (ii) a novel arbitrary-order Galerkin Reduction (GR) which does not use a grid, considerably reducing the number of state variables. A vectorized formulation facilitates the solution in two alternative ways: (i) in the time domain for arbitrary response via implicit integration using readily available routines; and (ii) in the frequency domain for the direct computation of self-excited periodic response via a novel Harmonic Balance (HB) method. GR and FD are cross-verified by time domain simulations which confirm that GR significantly reduces the computation time. Simulations also cross-verify the time and frequency domain solutions applied to the reference FD model and demonstrate the unique ability of HB to correctly accommodate structural damping.

  20. Durable solid lubricant coatings for foil gas bearings to 315 deg C

    NASA Technical Reports Server (NTRS)

    Wagner, R. C.; Sliney, H. E.

    1984-01-01

    The durability and friction characteristics of bonded solid lubricant films on compliant gas bearings were measured. Coating compositions, which were judged to be suitable for use to at least 315 C, were selected for this study. Most of the data were obtained with polyimide-bonded graphite fluoride coatings and with silicate-bonded graphite coatings. These coatings were applied to the bore of Inconel 750 foil bearings. The journals were A286 stainless steel, with a rms surface finish of 0.2 microns. The foils were subjected to repeated start/stop cycles under a 14 kPa (2 psi) bearing unit load. Sliding contact occurred during lift-off and coast down at surface velocities less than 6 m/s (3000 rpm). Testing continued until 9000 cycles were accumulated or until a rise in starting torque indicated that the coating had failed. The coatings were evaluated in the temperature range from 25 C to 315 C. Comparisons in coating performance as well as discussions of their properties and methods of application are given.

  1. Load Capacity Estimation of Foil Air Journal Bearings for Oil-Free Turbomachinery Applications

    NASA Technical Reports Server (NTRS)

    DellaCorte, Christopher; Valco, Mark J.

    2000-01-01

    This paper introduces a simple "Rule of Thumb" (ROT) method to estimate the load capacity of foil air journal bearings, which are self-acting compliant-surface hydrodynamic bearings being considered for Oil-Free turbo-machinery applications such as gas turbine engines. The ROT is based on first principles and data available in the literature and it relates bearing load capacity to the bearing size and speed through an empirically based load capacity coefficient, D. It is shown that load capacity is a linear function of bearing surface velocity and bearing projected area. Furthermore, it was found that the load capacity coefficient, D, is related to the design features of the bearing compliant members and operating conditions (speed and ambient temperature). Early bearing designs with basic or "first generation" compliant support elements have relatively low load capacity. More advanced bearings, in which the compliance of the support structure is tailored, have load capacities up to five times those of simpler designs. The ROT enables simplified load capacity estimation for foil air journal bearings and can guide development of new Oil-Free turbomachinery systems.

  2. Absolute configuration assignment of a chiral molecule in the gas phase using foil-induced Coulomb explosion imaging

    NASA Astrophysics Data System (ADS)

    Herwig, Philipp; Zawatzky, Kerstin; Schwalm, Dirk; Grieser, Manfred; Heber, Oded; Jordon-Thaden, Brandon; Krantz, Claude; Novotný, Oldřich; Repnow, Roland; Schurig, Volker; Vager, Zeev; Wolf, Andreas; Trapp, Oliver; Kreckel, Holger

    2014-11-01

    Chiral molecules exist in two configurations that are nonsuperposable mirror images of one another. The underlying molecular structure is referred to as the absolute configuration. In chiral environments, the handedness of molecules influences their chemical characteristics dramatically, and therefore the determination of absolute configurations is of fundamental interest in organic chemistry and biology. Commonly applied techniques to assign absolute configuration are anomalous single-crystal x-ray diffraction and vibrational circular dichroism. However, these techniques become increasingly more challenging when applied to molecules that are made out of light atoms exclusively. Furthermore, there is no established method to determine the absolute handedness of gas-phase molecules that are not optically active. In this work, we apply the foil-induced Coulomb explosion imaging technique to determine directly the absolute configuration of the chiral molecule trans-2,3-dideuterooxirane (C2OD2H2) in the gas phase. The experiment leads to the definitive assignment of the (R ,R ) configuration to an enantio-selected dideuterooxirane sample with a statistical confidence of 5 σ . As the handedness of trans-2,3-dideuterooxirane is unambiguously linked by chemical synthesis to the stereochemical key reference glyceraldehyde, our results provide an independent verification of the absolute configuration of the stereochemical reference standard.

  3. A method for fabrication of an activator from photopolymer plastic.

    PubMed

    Djurkova, A A; Stoilov, G N; Iovchev, S I

    2001-01-01

    The authors propose the fabrication of activators from photopolymerizing plastic. The advantages of this method are reviewed in comparison to the classical technology for fabrication of complicated constructions from hydropolymerizing plastic: Lack of residual monomer. Simplification of technology. Significant shortening of the time necessary to obtain the ready apparatus. Easy adjustment and good adaptation. The method is recommended as a method of choice in the practical fabrication of the activator for clinical application.

  4. Efficient laser-proton acceleration from an insulating foil with an attached small metal disk

    SciTech Connect

    Otani, Kazuto; Tokita, Shigeki; Nishoji, Toshihiko; Inoue, Shunsuke; Hashida, Masaki; Sakabe, Shuji

    2011-10-17

    Efficient proton acceleration by the interaction of an intense femtosecond laser pulse with a solid foil has been demonstrated. An aluminum coating (thickness: 0.2 {mu}m) on a polyethylene (PE) foil was irradiated at 2 x 10{sup 18} W/cm{sup 2} intensity. The protons from the aluminum-disk (diameter: 150 {mu}m to 15 mm) foil were accelerated to much higher energy in comparison with conventional targets such as PE and aluminum-coated PE foils. The fast electron signal along the foil surface was significantly higher from the aluminum-coated PE foil. The laser-proton acceleration appeared to be affected to the size of surrounding conductive material.

  5. Beam Loss due to Foil Scattering in the SNS Accumulator Ring

    SciTech Connect

    Holmes, Jeffrey A; Plum, Michael A

    2012-01-01

    In order to better understand the contribution of scattering from the primary stripper foil to losses in the SNS ring, we have carried out calculations using the ORBIT Code aimed at evaluating these losses. These calculations indicate that the probability of beam loss within one turn following a foil hit is ~1.8 10-8 , where is the foil thickness in g/cm2, assuming a carbon foil. Thus, for a typical SNS stripper foil of thickness = 390 g/cm2, the probability of loss within one turn of a foil hit is ~7.0 10-6. This note describes the calculations used to arrive at this result, presents the distribution of these losses around the SNS ring, and compares the calculated results with observed ring losses for a well-tuned production beam.

  6. A Monte Carlo studies of the entrance foil material in a target assembly for FDG production

    SciTech Connect

    Merouani, A.; El Khayati, N.; EL Ghayour, A.; El Alamy, H.; Zoubir, B.

    2015-07-01

    In this work, a Monte Carlo simulation was performed for different entrance foil Materials in the target assembly for [{sup 18}F] FDG production, to investigate the neutron generations in the entrance foil. However, the objective is to study a materials that has the more or less similar mechanical properties as the Havar{sup R} foil with less generation of secondary particles and without affecting, the yield of FDG production. (authors)

  7. Direct observation of spin-like reaction fronts in planar energetic multilayer foils.

    SciTech Connect

    Adams, David Price; Hodges, V. Carter; Jones, Eric D., Jr.; McDonald, Joel Patrick

    2008-10-01

    Propagating reactions in initially planar cobalt/aluminum exothermic multilayer foils have been investigated using high-speed digital photography. Real-time observations of reactions indicate that unsteady (spinlike) reaction propagation leads to the formation of highly periodic surface morphologies with length scales ranging from 1 {micro}m to 1 mm. The characteristics of propagating spinlike reactions and corresponding reacted foil morphologies depend on the bilayer thickness of multilayer foils.

  8. Large-area monolayer hexagonal boron nitride on Pt foil.

    PubMed

    Park, Ji-Hoon; Park, Jin Cheol; Yun, Seok Joon; Kim, Hyun; Luong, Dinh Hoa; Kim, Soo Min; Choi, Soo Ho; Yang, Woochul; Kong, Jing; Kim, Ki Kang; Lee, Young Hee

    2014-08-26

    Hexagonal boron nitride (h-BN) has recently been in the spotlight due to its numerous applications including its being an ideal substrate for two-dimensional electronics, a tunneling material for vertical tunneling devices, and a growth template for heterostructures. However, to obtain a large area of h-BN film while maintaining uniform thickness is still challenging and has not been realized. Here, we report the systematical study of h-BN growth on Pt foil by using low pressure chemical vapor deposition with a borazine source. The monolayer h-BN film was obtained over the whole Pt foil (2 × 5 cm(2)) under <100 mTorr, where the size is limited only by the Pt foil size. A borazine source was catalytically decomposed on the Pt surface, leading to the self-limiting growth of the monolayer without the associating precipitation, which is very similar to the growth of graphene on Cu. The orientation of the h-BN domains was largely confined by the Pt domain, which is confirmed by polarizing optical microscopy (POM) assisted by the nematic liquid crystal (LC) film. The total pressure and orientation of the Pt lattice plane are crucial parameters for thickness control. At high pressure (∼0.5 Torr), thick film was grown on Pt (111), and in contrast, thin film was grown on Pt (001). Our advances in monolayer h-BN growth will play an important role to further develop a high quality h-BN film that can be used for vertical tunneling, optoelectronic devices and growth templates for a variety of heterostructures.

  9. Recycling of aluminum foil from post-consumer beverage cartons

    SciTech Connect

    Charlier, P.; Sjoeberg, G.

    1995-12-31

    Recycling of aluminium contained in used aseptic beverage cartons is a difficult task which has nevertheless to be tackled by modern societies. Techniques have earlier been developed by the paper and pulp industry for the recycling of the board fibers from collected post-consumer beverage cartons. A joint technical feasibility study by Graenges and a leading beverage carton producer has dealt with different techniques for handling residues from repulsing facilities. The aluminium obtained can be used as raw material for the production of thin gauge foil, thus closing the recycling loop.

  10. Foil system fatigue load environments for commercial hydrofoil operation

    NASA Technical Reports Server (NTRS)

    Graves, D. L.

    1979-01-01

    The hydrofoil fatigue loads environment in the open sea is examined. The random nature of wave orbital velocities, periods and heights plus boat heading, speed and control system design are considered in the assessment of structural fatigue requirements. Major nonlinear load events such as hull slamming and foil unwetting are included in the fatigue environment. Full scale rough water load tests, field experience plus analytical loads work on the model 929 Jetfoil commercial hydrofoil are discussed. The problem of developing an overall sea environment for design is defined. State of the art analytical approaches are examined.

  11. Critical mass experiment using U-235 foils and lucite plates

    SciTech Connect

    Sanchez, R.; Butterfield, K.; Kimpland, R.; Jaegers, P.

    1998-05-01

    The main objective of this experiment was to show how the multiplication of the system increases as moderated material is placed between highly enriched uranium foils. In addition, this experiment served to demonstrate the hand-stacking techniques, and approach to criticality by remote operation. This experiment was designed by Tom McLaughlin in the mid seventies as part of the criticality safety course that is taught at Los Alamos Critical Experiment Facility (LACEF). The W-U-235 ratio for this experiment was 215 which is where the minimum critical mass for this configuration occurs.

  12. Prediction of Gas Lubricated Foil Journal Bearing Performance

    NASA Technical Reports Server (NTRS)

    Carpino, Marc; Talmage, Gita

    2003-01-01

    This report summarizes the progress in the first eight months of the project. The objectives of this research project are to theoretically predict the steady operating conditions and the rotor dynamic coefficients of gas foil journal bearings. The project is currently on or ahead of schedule with the development of a finite element code that predicts steady bearing performance characteristics such as film thickness, pressure, load, and drag. Graphical results for a typical bearing are presented in the report. Project plans for the next year are discussed.

  13. Gas Lubricated Foil Bearing Development for Advanced Turbomachines

    DTIC Science & Technology

    1977-03-01

    THIS PAGE (Alh.n )•af. Entered) REPOR DO T PAGE READ INSTRUCTIONS PORTBEFORE COMPLETING FORM (T-/WU) RP 1 VT ACCESSION NO |PIENT’S CATALOG NUMBER AFAP...1.3 Program Approach 6 Ii SU0RY 10 2.1 Analytical 10 2.2 Materials Development 13 2.3 Bearing Development and Testing 16 III DISCUSSION 19 3.1 Engine...to 1200*F. -~ 18 SECTION III A DISCUSSION 3.1 Engine Characteristics The ETJ341-Pl engine was selected as the vehicle for the Sapplication of foil

  14. One-Pot Solvothermal in Situ Growth of 1D Single-Crystalline NiSe on Ni Foil as Efficient and Stable Transparent Conductive Oxide Free Counter Electrodes for Dye-Sensitized Solar Cells.

    PubMed

    Bao, Chao; Li, Faxin; Wang, Jiali; Sun, Panpan; Huang, Niu; Sun, Yihua; Fang, Liang; Wang, Lei; Sun, Xiaohua

    2016-12-07

    One-dimensional single-crystal nanostructural nickel selenides were successfully in situ grown on metal nickel foils by two simple one-step solvothermal methods, which formed NiSe/Ni counter electrodes (CEs) for dye-sensitized solar cells (DSSCs). The nickel foil acted as the nickel source in the reaction process, a supporting substrate, and an electron transport "speedway". Electrochemical testing indicated that the top 1D single-crystal NiSe exhibited prominent electrocatalytic activity for I3(-) reduction. Due to the metallic conductivity of Ni substrate and the outstanding electrocatalytic activity of single-crystal NiSe, the DSSC based on a NiSe/Ni CE exhibited higher fill factor (FF) and larger short-circuit current density (Jsc) than the DSSC based on Pt/FTO CE. The corresponding power conversion efficiency (6.75%) outperformed that of the latter (6.18%). Moreover, the NiSe/Ni CEs also showed excellent electrochemical stability in the I(-)/I3(-) redox electrolyte. These findings indicated that single-crystal NiSe in situ grown on Ni substrate was a potential candidate to replace Pt/TCO as a cheap and highly efficient counter electrode of DSSC.

  15. Prescribing Activities that Engage Passive Residents. An Innovative Method

    PubMed Central

    Kolanowski, Ann; Buettner, Linda

    2009-01-01

    Individuals with dementia are often passive, which places them at risk for further cognitive and functional decline. Recreational activities have been used in research to reduce passive behaviors, but systematic reviews of these studies have found modest effect sizes for many activities. In this article, we describe the further theoretical development of an innovative method for prescribing activities that have a high likelihood of engaging nursing home residents who are passive and present examples for research application and clinical practice. This method may increase the effect size of activity interventions and encourage more widespread adoption of nonpharmacological interventions in practice. PMID:18274300

  16. Proactive interference and cuing effects in short-term cued recall: does foil context matter?

    PubMed

    Goh, Winston D; Tan, Huiqin

    2006-07-01

    Tehan and Humphreys's (1995, 1996) short-term cued recall paradigm showed that recall in short-term memory is cue driven. In critical trials, the participants studied two blocks of four words each and were required to forget the first block while remembering the second block. A foil in the first block (e.g., orange) was related to a target (e.g., carrot) in the second block. Proactive interference (PI) was evident when a retrieval cue was used that subsumed the foil and the target (e.g., type of juice), but not when a cue was used that subsumed only the target (e.g., type of vegetable). Four experiments were performed to examine the extent to which contextual organization in the foil block would enhance or diminish the foil's efficacy in creating PI. A novel condition was included in which the words in the foil block were studied in a phonologically related context but the target was cued semantically, and vice versa with a semantic context and phonological cue. There were no differences in recall accuracy between conditions with and without contextual organization, but reliable increases in foil intrusions were observed when contextual organization was present. Contextual organization enhanced the foil, rather than diminished it, but the strengthened foil generated PI only when the cue subsumed the foil and the target and had no effect when the cue subsumed only the target. The results are consistent with a cue-driven retrieval interpretation of short-term recall.

  17. Composite thin-foil bandpass filter for EUV astronomy Titanium-antimony-titanium

    NASA Technical Reports Server (NTRS)

    Jelinsky, P.; Martin, C.; Kimble, R.; Bowyer, S.; Steele, G.

    1983-01-01

    Thin metallic foils of antimony and titanium have been investigated in an attempt to develop an EUV filter with a bandpass from 350 to 550 A. A composite filter has been developed composed of antimony sandwiched between two titanium foils. The transmissions of sample composite foils and of pure titanium foils from 130 to 1216 A are presented. The absorption coefficients of anatimony and titanium and the effect of titanium oxide on the transmission are derived. The composite filter has been found to be quite stable and mechanically rugged. Among other uses, the filter shows substantial promise for EUV astronomy.

  18. Enhanced high harmonic generation and the phase effect in double-sided relativistic laser-foil interaction

    SciTech Connect

    Yu Yahong; Shen Baifei; Ji Liangliang; Zhang Xiaomei; Wang Wenpeng; Zhao Xueyan; Wang Xiaofeng; Yi Longqing; Shi Yin; Xu Tongjun; Zhang Lingang; Xu Zhizhan

    2013-03-15

    High harmonic generation (HHG) from relativistic laser-foil interaction is investigated analytically and through particle-in-cell simulations. Previous work has shown that when two counter-propagating circularly polarized (CP) laser pulses interact with a thin foil, electrons can be well confined spatially to form a high density layer. The layer electrons oscillate in certain transversal direction and radiate intense high order harmonics. It is demonstrated here that there is a critical foil thickness, only below which can high harmonics be generated efficiently. Furthermore, to enhance the intensity in higher order region, the third linearly polarized (LP) short-wavelength laser pulse with much lower intensity is introduced. Analysis and simulations both show that the enhancement is determined by the relative phase {delta}{phi} between the driving CP laser pulses and LP pulse. The enhancement at high order is quite considerable and very sensitive to the relative phase {delta}{phi}, thus offering not only a way to efficiently produce HHG but also a new method to measure the phase of intense high-frequency laser pulses.

  19. The “accumulation effect” of positrons in the stack of foils, detected by measurements of the positron implantation profile

    SciTech Connect

    Dryzek, Jerzy; Siemek, Krzysztof

    2013-12-14

    The profiles of positrons implanted from the radioactive source {sup 22}Na into a stack of foils and plates are the subject of our experimental and theoretical studies. The measurements were performed using the depth scanning of positron implantation profile method, and the theoretical calculations using the phenomenological multi-scattering model (MSM). Several stacks consisting of silver, gold and aluminum foils, and titanium and germanium plates were investigated. We notice that the MSM describes well the experimental profiles; however when the stack consisting of silver and gold foils, the backscattering and linear absorption coefficients differ significantly from those reported in the literature. We suggest the energy dependency of the backscattering coefficient for silver and gold. In the stacks which comprise titanium and germanium plates, there were observed the features, which indicate the presence of the “accumulation effect” in the experimental implantation profile. This effect was previously detected in implantation profiles in Monte Carlo simulations using the GEANT4 tool kit, and it consists in higher localization of positrons close the interface. We suppose that this effect can be essential for positron annihilation in any heterogeneous materials.

  20. Aluminium foil as a single-use substrate for MALDI-MS fingerprinting of different melanoma cell lines.

    PubMed

    Bondarenko, A; Zhu, Y; Qiao, L; Cortés Salazar, F; Pick, H; Girault, H H

    2016-05-23

    Herein, we present the intact cell matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) for the fingerprinting of human melanoma cancer cell lines grown on aluminium foil. To perform the MALDI-MS assay, melanoma cells were cultured on a flat and thin foil, which was directly transferred to the target plate of MALDI-MS for analysis. The influence of a wide range of cell fixation protocols (i.e. formalin-based and alcohol-based methods) and MALDI matrices on the obtained characteristic spectra was investigated. For the optimization of the MALDI-MS protocol, the MS fingerprints of the melanoma WM-239 cell line with and without an overexpressed enhanced green fluorescent protein were employed. The fingerprints obtained from WM-239 cells grown on aluminium foil were compared with the intact cell MALDI-MS of the cell pellet and presented higher sensitivity in a high m/z range. The optimized protocol was subsequently applied to characterise melanoma cell lines derived from different cancer stages and allowed identification of unique MS signals that could be used for differentiation between the studied cell lines (i.e. molecular weight equal to 10.0 kDa and 26.1 kDa).

  1. How Thin Is Foil? Applying Density to Find the Thickness of Aluminum Foil

    ERIC Educational Resources Information Center

    Concannon, James P.

    2011-01-01

    In this activity, I show how high school students apply their knowledge of density to solve an unknown variable, such as thickness. Students leave this activity with a better understanding of density, the knowledge that density is a characteristic property of a given substance, and the ways density can be measured. (Contains 4 figures and 1 table.)

  2. Accuracy of activPAL Self-Attachment Methods

    ERIC Educational Resources Information Center

    Kringen, Nina L.; Healy, Genevieve N.; Winkler, Elisabeth A. H.; Clark, Bronwyn K.

    2016-01-01

    This study examined the accuracy of self-attachment of the activPAL activity monitor. A convenience sample of 50 participants self-attached the monitor after being presented with written material only (WMO) and then written and video (WV) instructions; and completed a questionnaire regarding the acceptability of the instructional methods.…

  3. Social Activity Method (SAM): A Fractal Language for Mathematics

    ERIC Educational Resources Information Center

    Dowling, Paul

    2013-01-01

    In this paper I shall present and develop my organisational language, "social activity method" (SAM), and illustrate some of its applications. I shall introduce a new scheme for "modes of recontextualisation" that enables the analysis of the ways in which one activity--which might be school mathematics or social research or any…

  4. Empirical Evidence or Intuition? An Activity Involving the Scientific Method

    ERIC Educational Resources Information Center

    Overway, Ken

    2007-01-01

    Students need to have basic understanding of scientific method during their introductory science classes and for this purpose an activity was devised which involved a game based on famous Monty Hall game problem. This particular activity allowed students to banish or confirm their intuition based on empirical evidence.

  5. Experimental Observations of the Electrothermal Instability on Thin Foils

    NASA Astrophysics Data System (ADS)

    Steiner, Adam; Campbell, Paul; Yager-Elorriaga, David; Jordan, Nicholas; Lau, Y. Y.; Gilgenbach, Ronald

    2016-10-01

    The electrothermal instability (ETI) arises whenever a current-carrying material has a resistivity that depends on temperature. When resistivity increases with increasing temperature, ETI causes striations to form perpendicular to the direction of current. On pulsed-power-driven, ablating metallic loads, this process can cause sections of the target to ablate earlier than the bulk material, creating a macroscopic surface perturbation on the plasma surface that can seed hydrodynamic instabilities, such as the magneto Rayleigh-Taylor (MRT) instability. Experiments have been performed to observe the self-emission of ablating planar aluminum and tantalum foils using a 12-frame ultrafast ICCD camera with 2 μm spatial resolution and 5 ns time resolution. Other diagnostics include voltage, current, and optical spectroscopy. Ablations of foils ranging from 0.4 to 2 μm in thickness are driven with a 4 kA, 600 ns risetime pulse generator. Striations of hotter, brighter material forming perpendicular to current are consistently observed. These measurements provide experimental evidence of the growth of ETI as a temperature perturbation on initially solid metal loads. This research was supported by the Department of Energy through Award DE-SC0012328, AFOSR Grant #FA9550-15-1-0419, and Sandia National Laboratories.

  6. Effect of defence response time during lunge in foil fencing.

    PubMed

    Gutiérrez-Cruz, Carmen; Rojas, F Javier; Gutiérrez-Davila, Marcos

    2016-01-01

    The aim of this study was to analyse the effect of stimulus change timing on reaction response time parameters, horizontal velocity of the centre of mass (CM) and precision during offensive actions in fencing. Twelve fencers from the Spanish National Foil Team were included in the study. Two 500 Hz force plates were used to register the horizontal component of the reaction force while a 3D video camera set at 250 Hz recorded the spatial position of 11 body markers and a projector connected to a programmed stopwatch projected a moving target (stimulus) on a screen. When the circle (target) appeared in the centre of the plastron, fencers had to execute a step-forward-lunge as fast as possible, trying to touch the circle with the tip of the foil. During the lunge, the position of the target could randomly shift or not to three different positions. The stimulus change was performed randomly at four different times with a progressive delay. The results show that target changes did not have any effect when they occurred at the beginning of the movement sequence. However, when the target change was delayed, reaction and movement times increased and the technical execution of the lunge changed, leading to more errors.

  7. Influence of copper foil polycrystalline structure on graphene anisotropic etching

    NASA Astrophysics Data System (ADS)

    Sharma, Kamal P.; Mahyavanshi, Rakesh D.; Kalita, Golap; Tanemura, Masaki

    2017-01-01

    Anisotropic etching of graphene and other two dimensional materials is an important tool to understand the growth process as well as enabling fabrication of various well-defined structures. Here, we reveal the influence of copper foil polycrystalline structure on anisotropic etching process of as-synthesized graphene. Graphene crystals were synthesized on the polycrystalline Cu foil by a low-pressure chemical vapor deposition (LPCVD) system. Microscopic analysis shows difference in shape, size and stripes alignment of graphene crystals with dissimilar nucleation within closure vicinity of neighboring Cu grains. Post-growth etching of such graphene crystals also significantly affected by the crystallographic nature of Cu grains as observed by the field emission scanning electron microscope (FE-SEM) and electron back scattered diffraction (EBSD) analysis. Hexagonal hole formation with anisotropic etching is observed to be independent of the stripes and wrinkles in the synthesized graphene. We also observed variation in etched pattern of the graphene depending on the base Cu grain orientations, attributing to difference in nucleation and growth process. The findings can facilitate to understand the nature of microscopic etched pattern depending on metal catalyst crystallographic structure.

  8. The radiation reaction effect in ultra intense laser foil interactions

    NASA Astrophysics Data System (ADS)

    Klimo, O.; Jirka, M.; Masek, M.; Limpouch, J.; Bussmann, M.; Korn, G.

    2013-05-01

    Since the radiation reaction effect on electron propagation is very small in most cases, it can be usually neglected and the Lorentz force equation can be applied. However, ultra-intense lasers with normalized vector potential of the order of 100 can accelerate electrons to relativistic velocities with very high gamma factor. When the electron is accelerated to such high velocities the amount of emitted radiation may become large and radiation damping and emission of energetic photons should be considered. This work studies the influence of the radiation reaction force on laser interaction with solid foil targets. It compares different approaches adopted in PIC simulations to take into account the radiation reaction. The simulations of a counter-propagating relativistic electron and an ultra-intense laser beam demonstrate a strong energy loss of electrons due to non-linear Compton scattering. The interaction of ultra-intense laser pulse with solid foil is studied using PIC simulations. It is shown that the effect of radiation reaction strongly depends on the recirculation of high-energy electrons. When the recirculation is efficient, the radiation coming from the target is much more intense and it shows different spectral and angular characteristics.

  9. Improved composite targets for small scale 64Cu production comparing Au- and Pt-foils as 64Ni backing

    NASA Astrophysics Data System (ADS)

    Walther, M.; Preusche, S.; Fuechtner, F.; Pietzsch, H. J.; Steinbach, J.

    2012-12-01

    Advantages of a stacked assembly of target support components for 64Cu production via 64Ni(p,n)64Cu reaction were reported recently. The present work shows the applicability of these composite targets for beam currents up to 22 μA. Gold and platinum foils were evaluated as 64Ni backing. The effective specific activity (ESA) and specific activity (SA) were determined by TETA titration at room temperature and at 80 °C and compared with additional copper quantification results via ICP-MS and stripping voltammetric trace analysis (VA).

  10. Experimental feasibility study of radial injection cooling of three-pad radial air foil bearings

    NASA Astrophysics Data System (ADS)

    Shrestha, Suman K.

    Air foil bearings use ambient air as a lubricant allowing environment-friendly operation. When they are designed, installed, and operated properly, air foil bearings are very cost effective and reliable solution to oil-free turbomachinery. Because air is used as a lubricant, there are no mechanical contacts between the rotor and bearings and when the rotor is lifted off the bearing, near frictionless quiet operation is possible. However, due to the high speed operation, thermal management is one of the very important design factors to consider. Most widely accepted practice of the cooling method is axial cooling, which uses cooling air passing through heat exchange channels formed underneath the bearing pad. Advantage is no hardware modification to implement the axial cooling because elastic foundation structure of foil bearing serves as a heat exchange channels. Disadvantage is axial temperature gradient on the journal shaft and bearing. This work presents the experimental feasibility study of alternative cooling method using radial injection of cooling air directly on the rotor shaft. The injection speeds, number of nozzles, location of nozzles, total air flow rate are important factors determining the effectiveness of the radial injection cooling method. Effectiveness of the radial injection cooling was compared with traditional axial cooling method. A previously constructed test rig was modified to accommodate a new motor with higher torque and radial injection cooling. The radial injection cooling utilizes the direct air injection to the inlet region of air film from three locations at 120° from one another with each location having three axially separated holes. In axial cooling, a certain axial pressure gradient is applied across the bearing to induce axial cooling air through bump foil channels. For the comparison of the two methods, the same amount of cooling air flow rate was used for both axial cooling and radial injection. Cooling air flow rate was

  11. Critical mass experiment using U-235 foils-SiO{sub 2}-polyethylene plates

    SciTech Connect

    Sanchez, R.; Kimpland, R.; Butterfield, K.; Jaegers, P.; Casson, W.

    1998-12-31

    Fissile material in waste is frequently encountered in decontamination and decommissioning activities. Thousands of drums containing radioactive waste are stored in storage facilities throughout the DOE complex. The amount of fissile material in each drum is generally small because of the criticality safety limits that have been calculated using neutron transport computer codes such as MCNP, KENO, or ONEDANT. No experimental critical data are available to assure the correctiveness of the calculations for those systems containing fissile material (U-235, U-233, and Pu-239) in contact with matrix material (Al{sub 2}O{sub 3}, CaO, MgO, and SiO{sub 2}) in the drums. The purpose of the U-235 foil-SiO{sub 2}-polyethylene experiment is to provide experimental data to validate the computer transport codes and the cross section data.

  12. Critical mass experiment using {sup 235}U foil-SiO{sub 2}-polyethylene plates

    SciTech Connect

    Sanchez, R.; Kimpland, R.; Butterfield, K.; Jaegers, P.; Casson, W.

    1998-12-31

    Fissile material in waste is frequently encountered in decontamination and decommissioning activities. Thousands of drums containing radioactive waste are stored in storage facilities throughout the US Department of Energy (DOE) complex. The amount of fissile material in each drum is generally small because of the criticality safety limits that have been calculated using neutron transport computer codes such as MCNP, KENO, or ONEDANT. No experimental critical data are available to ensure the correctness of the calculations for those systems containing fissile material ({sup 235}U, {sup 233}U, and {sup 239}Pu) in contact with matrix material (Al{sub 2}O{sub 3}, CaO, MgO, and SiO{sub 2}) in the drums. The purpose of the {sup 235}U foil-SiO{sub 2}-polyethylene experiment is to provide experimental data to validate the computer transport codes and the cross-section data.

  13. PIXE and neutron activation methods in human hair material analysis

    NASA Astrophysics Data System (ADS)

    Bǎdicǎ, T.; Ciortea, C.; Cojocaru, V.; Ivaşcu, M.; Petrovici, A.; Popa, A.; Popescu, I.; Sǎlǎgean, M.; Spiridon, S.

    1984-04-01

    In order to compare some of the nuclear methods in human hair material analysis, proton induced X-ray excitation and variant techniques of neutron activation analysis have been used. The elemental concentrations are compared with the IAEA-Vienna certified values. The efficiency and reliability of the methods used are briefly discussed.

  14. An in vitro method for evaluating vascular endothelial ADPase activity.

    PubMed

    Caprino, L; Togna, A R; Stella, C; Togna, G

    1996-06-01

    Some xenobiotics, known to promote the development of thrombotic phenomena, affect vascular endothelium ADPase, a regulatory enzyme that inactivates vaso- and platelet-active adenine nucleotides. This proposed new experimental approach represents an improved method of evaluation of vascular endothelial ADPase activity which is assessed by measuring, at pre-established times, the degradation rate of exogenous ADP incubated with aortic bovine patches. The ADP dosage was performed by using a spectrophotometric enzymatic assay. Statistical analyses showed that the method is capable of highlighting the linearity of the ADPase activity time-course, thus indicating that the slopes of time-degradation curves of ADP are a valid index for this endothelial ectoenzyme activity. Results obtained with ADPase inhibiting or stimulating agent confirm that this in vitro method is an efficient tool for estimating the ability of xenobiotics or drugs to modify the nonthrombogenic properties of vascular endothelium.

  15. Digital methods of photopeak integration in activation analysis.

    NASA Technical Reports Server (NTRS)

    Baedecker, P. A.

    1971-01-01

    A study of the precision attainable by several methods of gamma-ray photopeak integration has been carried out. The 'total peak area' method, the methods proposed by Covell, Sterlinski, and Quittner, and some modifications of these methods have been considered. A modification by Wasson of the total peak area method is considered to be the most advantageous due to its simplicity and the relatively high precision obtainable with this technique. A computer routine for the analysis of spectral data from nondestructive activation analysis experiments employing a Ge(Li) detector-spectrometer system is described.

  16. Neutron activation analysis of certified samples by the absolute method

    NASA Astrophysics Data System (ADS)

    Kadem, F.; Belouadah, N.; Idiri, Z.

    2015-07-01

    The nuclear reactions analysis technique is mainly based on the relative method or the use of activation cross sections. In order to validate nuclear data for the calculated cross section evaluated from systematic studies, we used the neutron activation analysis technique (NAA) to determine the various constituent concentrations of certified samples for animal blood, milk and hay. In this analysis, the absolute method is used. The neutron activation technique involves irradiating the sample and subsequently performing a measurement of the activity of the sample. The fundamental equation of the activation connects several physical parameters including the cross section that is essential for the quantitative determination of the different elements composing the sample without resorting to the use of standard sample. Called the absolute method, it allows a measurement as accurate as the relative method. The results obtained by the absolute method showed that the values are as precise as the relative method requiring the use of standard sample for each element to be quantified.

  17. Foil-hole and data image quality assessment in 3DEM: Towards high-throughput image acquisition in the electron microscope.

    PubMed

    Vargas, J; Franken, E; Sorzano, C O S; Gomez-Blanco, J; Schoenmakers, R; Koster, A J; Carazo, J M

    2016-12-01

    Automatic or semiautomatic data collection approaches on a transmission electron microscope (TEM) for Single Particle Analysis, capable of acquiring large datasets composed of only high quality images, are of great importance to obtain 3D density maps with the highest resolution possible. Typically, this task is performed by an experienced microscopist, who manually decides to keep or discard images according to subjective criteria. Therefore, this methodology is slow, intensive in human work and subjective. In this work, we propose a method to automatically or semiautomatically perform this image selection task. The approach is based on some simple, fast and effective image quality descriptors, which can be computed during acquisition, to characterize foil-hole and data images. The proposed approach has been used to evaluate the quality of different datasets consisting of foil-hole and data images obtained with a FEI Titan Krios electron microscope. The results show that the proposed method is very effective evaluating the quality of foil-hole and data images, as well as predicting the quality of the data images from the foil-hole images.

  18. Prism Foil from an LCD Monitor as a Tool for Teaching Introductory Optics

    ERIC Educational Resources Information Center

    Planinsic, Gorazd; Gojkosek, Mihael

    2011-01-01

    Transparent prism foil is part of a backlight system in LCD monitors that are widely used today. This paper describes the optical properties of the prism foil and several pedagogical applications suitable for undergraduate introductory physics level. Examples include experiments that employ refraction, total internal reflection, diffraction and…

  19. Effects of the foil flatness on irradiation performance of U10Mo monolithic mini-plates

    DOE PAGES

    Ozaltun, Hakan; Medvedev, Pavel G.; Rabin, Barry H.

    2015-09-03

    Monolithic plate-type fuels comprise of a high density, low enrichment, U10Mo fuel foil encapsulated in a cladding material. This concept generates several fabrication challenges such as flatness, centering or thickness variation. There are concerns, if these parameters have implications on overall performance. To investigate these inquiries, the effects of the foil flatness were studied. For this, a representative plate was simulated for an ideal case. The simulations were repeated for additional cases with various foil curvatures to evaluate the effects on the irradiation performance. The results revealed that the stresses and strains induced by fabrication process are not affected bymore » the flatness of the foil. Furthermore, fabrication stresses in the foil are relieved relatively fast in the reactor. The effects of the foil flatness on peak irradiation stressstrains are minimal. There is a slight increase in temperature for the case with maximum curvature. The major impact is on the displacement characteristics. Furthermore, while the case with a flat foil produces a symmetrical swelling, if the foil is curved, more swelling occurs on the thin-cladding side and the plate bows during irradiation.« less

  20. Effects of the foil flatness on irradiation performance of U10Mo monolithic mini-plates

    SciTech Connect

    Ozaltun, Hakan; Medvedev, Pavel G.; Rabin, Barry H.

    2015-09-03

    Monolithic plate-type fuels comprise of a high density, low enrichment, U10Mo fuel foil encapsulated in a cladding material. This concept generates several fabrication challenges such as flatness, centering or thickness variation. There are concerns, if these parameters have implications on overall performance. To investigate these inquiries, the effects of the foil flatness were studied. For this, a representative plate was simulated for an ideal case. The simulations were repeated for additional cases with various foil curvatures to evaluate the effects on the irradiation performance. The results revealed that the stresses and strains induced by fabrication process are not affected by the flatness of the foil. Furthermore, fabrication stresses in the foil are relieved relatively fast in the reactor. The effects of the foil flatness on peak irradiation stressstrains are minimal. There is a slight increase in temperature for the case with maximum curvature. The major impact is on the displacement characteristics. Furthermore, while the case with a flat foil produces a symmetrical swelling, if the foil is curved, more swelling occurs on the thin-cladding side and the plate bows during irradiation.

  1. 21 CFR 189.301 - Tin-coated lead foil capsules for wine bottles.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Tin-coated lead foil capsules for wine bottles... Addition to Human Food Through Food-Contact Surfaces § 189.301 Tin-coated lead foil capsules for wine... and neck areas) on wine bottles to prevent insect infestation, as a barrier to oxygen, and...

  2. Observational methods used to assess rat behavior: general activity.

    PubMed

    Paul, Carol Ann; Beltz, Barbara; Berger-Sweeney, Joanne

    2007-09-01

    INTRODUCTIONThe activity-inactivity continuum is an important parameter of behavior, and quantification of overall locomotor activity in the rat should identify it as a naturally nocturnal animal. Disruptions in nocturnal activity can be caused by damage in visual inputs to the brain or damage in the hypothalamus. Many commercial devices are available to measure activity automatically; some can be integrated with a computer to allow overnight monitoring in the absence of an observer. A less sophisticated but still accurate method of measuring activity is to create a home-made activity chamber by replacing the bottom of a box with Plexiglas or by marking lines on the bottom of a clean rat cage so that the observer can record rat activity by noting when the lines are crossed, while simultaneously recording other behaviors. Activity in rat pups can be observed as soon as they are 10 days old using smaller activity chambers. This protocol describes the construction of a home-made activity chamber and how to measure four activities: locomotion, rearing, circling, and grooming.

  3. High fidelity studies of exploding foil initiator bridges, Part 3: ALEGRA MHD simulations

    NASA Astrophysics Data System (ADS)

    Neal, William; Garasi, Christopher

    2017-01-01

    Simulations of high voltage detonators, such as Exploding Bridgewire (EBW) and Exploding Foil Initiators (EFI), have historically been simple, often empirical, one-dimensional models capable of predicting parameters such as current, voltage, and in the case of EFIs, flyer velocity. Experimental methods have correspondingly generally been limited to the same parameters. With the advent of complex, first principles magnetohydrodynamic codes such as ALEGRA and ALE-MHD, it is now possible to simulate these components in three dimensions, and predict a much greater range of parameters than before. A significant improvement in experimental capability was therefore required to ensure these simulations could be adequately verified. In this third paper of a three part study, the experimental results presented in part 2 are compared against 3-dimensional MHD simulations. This improved experimental capability, along with advanced simulations, offer an opportunity to gain a greater understanding of the processes behind the functioning of EBW and EFI detonators.

  4. Thermodynamical calculation of metal heating in nanosecond exploding wire and foil experiments.

    PubMed

    Sarkisov, G S; Rosenthal, S E; Struve, K W

    2007-04-01

    A method of thermodynamical calculation of thin metal wire heating during its electrical explosion is discussed. The technique is based on a calculation of Joule energy deposition taking into account the current wave form and the temperature dependence of the resistivity and heat capacity of the metal. Comparing the calculation to a set of exploding tungsten wire experiments demonstrates good agreement up to the time of melting. Good agreement is also demonstrated with resistive magnetohydrodynamics simulation. A similar thermodynamical calculation for Mo, Ti, Ni, Fe, Al, and Cu shows good agreement with experimental data. The thermodynamical technique is useful for verification of the voltage measurements in exploding wire experiments. This technique also shows good agreement with an exploding W foil experiment.

  5. Ion track symmetric and asymmetric nanopores in polyethylene terephthalate foils for versatile applications

    NASA Astrophysics Data System (ADS)

    Apel, P. Yu.; Blonskaya, I. V.; Dmitriev, S. N.; Orelovich, O. L.; Sartowska, B. A.

    2015-12-01

    In this report we present several fabrication methods which allow production of ion track nanopore membranes with different pore configurations. Polymer foils, typically polyethylene terephthalate with a thickness of 5-23 μm, are irradiated with accelerated heavy ions (energy of 1-10 MeV/u) and then subjected to different physico-chemical treatments. Depending on the procedure, symmetric or asymmetric pores with nanoscale-sized narrowing are obtained. The asymmetric configurations include conical, funnel-like and bullet-like shapes. In electrolyte solutions the asymmetric nanopores exhibit diode-like properties which strongly depend on the pore shape. The peculiar features of such pores provide a basis for various applications.

  6. Polymer-ZnO nanocomposites foils and thin films for UV protection

    SciTech Connect

    Shanshool, Haider Mohammed; Yahaya, Muhammad; Abdullah, Ibtisam Yahya; Yunus, Wan Mahmood Mat

    2014-09-03

    The damage of UV radiation on human eye and skin is extensively studied. In the present work, the nanocomposites foils and thin films have been prepared by using casting method and spin coating, respectively. Nanocomposites were prepared by mixing ZnO nanoparticles with Polymethyl methacrylate (PMMA) and Polyvinylidene fluoride (PVDF) as polymer matrix. Different contents of ZnO nanoparticles were used as filler in the nanocomposites. UV-Vis spectra showed very low transmittance in UV region that decreases with increase content of ZnO. PVDF/ZnO samples showed the lowest transmittance. The rough surface of PVDF was observed from SEM image. While a homogeneous dispersion of ZnO nanoparticles in PMMA were indicated by FESEM images.

  7. Lead foil in dental X-ray film: Backscattering rejection or image intensifier?

    NASA Astrophysics Data System (ADS)

    Hönnicke, M. G.; Delben, G. J.; Godoi, W. C.; Swinka-Filho, V.

    2014-11-01

    Dental X-ray films are still largely used due to sterilization issues, simplicity and, mainly, economic reasons. These films almost always are double coated (double emulsion) and have a lead foil in contact with the film for X-ray backscattering rejection. Herein we explore the use of the lead foil as an image intensifier. In these studies, spatial resolution was investigated when images were acquired on the dental X-ray films with and without the lead foil. Also, the lead foil was subjected to atomic analysis (fluorescent measurements) and structure analysis (X-ray diffraction). We determined that the use of the lead foil reduces the exposure time, however, does not affect the spatial resolution on the acquired images. This suggests that the fluorescent radiation spread is smaller than the grain sizes of the dental X-ray films.

  8. Design, fabrication, and performance of foil journal bearing for the brayton rotating unit

    NASA Technical Reports Server (NTRS)

    Licht, L.; Branger, M.

    1973-01-01

    Foil bearings were designed and manufactured to replace pivoted-shoe journal bearings in an existing Brayton Cycle turbo-alternator-compressor. The design of this unconventional rotor support was accomplished within the constraints and space limitations imposed by the present machine, and the substitution of foil bearings was effected without changes or modification other machine components. A housing and a test rig were constructed to incorporate the new foil-bearing support into a unified assemble with an air-driven rotor and the gimbal-mounted thrust bearing, seals, and shrouds of an actual Brayton Rotating Unit. The foil bearing required no external pressure source, and stable self-acting rotation was achieved at all speeds up to 43,200 rpm. Excellent wipe-wear characteristics of the foil bearing permitted well over 1000 start-stop cycles with no deterioriation of performance in the entire speed range.

  9. Characterization of the Fine Component of Comet Wild 2: Analysis of 11 Stardust Craters from Foil C2010W

    NASA Astrophysics Data System (ADS)

    Haas, B. A.; Croat, T. K.; Floss, C.

    2016-08-01

    NASA's Stardust mission returned cometary material from comet Wild 2 in Al foil collectors. We report on SEM-EDX and Auger elemental analysis as well as FIB-TEM analysis performed on 11 craters from foil C2010W.

  10. Vortex-wake interactions of a flapping foil that models animal swimming and flight.

    PubMed

    Lentink, David; Muijres, Florian T; Donker-Duyvis, Frits J; van Leeuwen, Johan L

    2008-01-01

    The fluid dynamics of many swimming and flying animals involves the generation and shedding of vortices into the wake. Here we studied the dynamics of similar vortices shed by a simple two-dimensional flapping foil in a soap-film tunnel. The flapping foil models an animal wing, fin or tail in forward locomotion. The vortical flow induced by the foil is correlated to (the resulting) thickness variations in the soap film. We visualized these thickness variations through light diffraction and recorded it with a digital high speed camera. This set-up enabled us to study the influence of foil kinematics on vortex-wake interactions. We varied the dimensionless wavelength of the foil (lambda*=4-24) at a constant dimensionless flapping amplitude (A*=1.5) and geometric angle of attack amplitude (A(alpha,geo)=15 degrees ). The corresponding Reynolds number was of the order of 1000. Such values are relevant for animal swimming and flight. We found that a significant leading edge vortex (LEV) was generated by the foil at low dimensionless wavelengths (lambda*<10). The LEV separated from the foil for all dimensionless wavelengths. The relative time (compared with the flapping period) that the unstable LEV stayed above the flapping foil increased for decreasing dimensionless wavelengths. As the dimensionless wavelength decreased, the wake dynamics evolved from a wavy von Kármán-like vortex wake shed along the sinusoidal path of the foil into a wake densely packed with large interacting vortices. We found that strongly interacting vortices could change the wake topology abruptly. This occurred when vortices were close enough to merge or tear each other apart. Our experiments show that relatively small changes in the kinematics of a flapping foil can alter the topology of the vortex wake drastically.

  11. Performance and lifetime of solar mirror foils in space

    SciTech Connect

    Fink, D.; Biersack, J.P.; Staedele, M.

    1985-01-01

    The results of a Monte Carlo computer analysis of the long term effects of space radiation on the surfaces of giant orbiting mirrors are presented. The mirrors, thin surfaced and made of substances like, e.g., Mylar and Hostephan, which are polymers, would reflect solar radiation to earth and be of a size equivalent to that of the area they would illumine. Possible applications are the warming of cities, melting of icebergs in shipping lanes and the illumination of solar power plants. Attention was focused on the changes produced in the reflective surface by solar wind particle bombardment. It was found that an Al covering at least 0.1 mm thick would be needed for protection. Nevertheless, the surface would be destroyed by blistering and foil carbonization within 10 yr and would then require replacement. 12 references.

  12. Folding/Unfolding Properties of Metal Foils in Transformable Structure

    NASA Astrophysics Data System (ADS)

    Daming, Nie; Zhen, Lu; Kaifeng, Zhang

    2016-11-01

    Transformable structures are widely applied in the aerospace, temporary facilities, etc. Compared to the structures made of polyester materials, the metal foil ones occupy many special advantages while have been rarely investigated. In this study, a series of transformable structures made of four different metal materials, 6065 Al, copper, TA1 and SUS 304 stainless steel, with thickness of 0.1 mm were prepared. Moreover, the folding (i.e., compressing the structure to the lowest height with external force) and unfolding (i.e., extending the structure to the largest height with external force) behaviors of these structures were exhibited and explained by experiments. Besides, the differences and corresponding mechanisms of various materials on the folding/unfolding properties of the structures were examined and discussed.

  13. Folding/Unfolding Properties of Metal Foils in Transformable Structure

    NASA Astrophysics Data System (ADS)

    Daming, Nie; Zhen, Lu; Kaifeng, Zhang

    2017-01-01

    Transformable structures are widely applied in the aerospace, temporary facilities, etc. Compared to the structures made of polyester materials, the metal foil ones occupy many special advantages while have been rarely investigated. In this study, a series of transformable structures made of four different metal materials, 6065 Al, copper, TA1 and SUS 304 stainless steel, with thickness of 0.1 mm were prepared. Moreover, the folding (i.e., compressing the structure to the lowest height with external force) and unfolding (i.e., extending the structure to the largest height with external force) behaviors of these structures were exhibited and explained by experiments. Besides, the differences and corresponding mechanisms of various materials on the folding/unfolding properties of the structures were examined and discussed.

  14. Flow structures in the wake of heaving and pitching foils

    NASA Astrophysics Data System (ADS)

    Najdzin, Derek; Pardo, Enrique; Leftwich, Megan C.; Bardet, Philippe M.

    2012-11-01

    A 10-bar mechanism drives a cambering hydrofoil in an oscillatory heaving and pitching motion that replicates the flapping motion of a dolphin tail. The mechanism sits on a force-balance with six strain gages that together measure the forces and moments experienced by the fin during an oscillation. Planar Laser-Induced Fluorescence is used to image the flow structures created downstream of the cambering fin for a range of Reynolds and Strouhal numbers. The images are taken in the mid-plane, parallel to the bottom of the water tunnel. These results are compared to a rigid foil at matching conditions to investigate the role of camber changes during the flapping cycle.

  15. Transitions in the wake of a flapping foil.

    PubMed

    Godoy-Diana, Ramiro; Aider, Jean-Luc; Wesfreid, José Eduardo

    2008-01-01

    We study experimentally the vortex streets produced by a flapping foil in a hydrodynamic tunnel, using two-dimensional particle image velocimetry. An analysis in terms of a flapping frequency-amplitude phase space allows the identification of (i) the transition from the well-known Bénard-von Kármán (BvK) wake to the reverse BvK vortex street that characterizes propulsive wakes, and (ii) the symmetry breaking of this reverse BvK pattern giving rise to an asymmetric wake. We also show that the transition from a BvK wake to a reverse BvK wake precedes the actual drag-thrust transition and we discuss the significance of the present results in the analysis of flapping systems in nature.

  16. Pulse shortening via Relativistic Transparency of Nanometer Foils

    NASA Astrophysics Data System (ADS)

    Shah, R. C.; Palaniyappan, S.; Wu, H.-C.; Gautier, D. C.; Jung, D.; Hoerlein, R.; Offermann, D.; Johnson, R. P.; Shimada, T.; Letzring, S.; Yin, L.; Albright, B.; Fernandez, J. C.; Hegelich, B. M.

    2010-11-01

    Intense lasers drive plasma electrons to velocities approaching light-speed. Increase of the electron mass causes optical transparency in otherwise classically over-dense plasma. Simulations indicate relativistic transparency can produce near-single-cycle rise time light pulses. It also lies enables a new mechanism for laser-based ion-acceleration yielding energy increases over earlier approaches. A direct signature of transparency is pulse-shortening thru over-dense plasmas in which relativistic intensity induces transmission. Using nm C foils (LMU) and the high-contrast Trident laser (LANL) we have made auto-correlation measurements showing >2x transmitted pulse duration reduction at intensities corresponding to ˜20-fold increase in electron mass. Spectral measurements agree with pulse shortening thru the target, and 1-D particle-in-cell simulations support the measurements.

  17. Effects of silver and group II fluoride solid lubricant additions to plasma-sprayed chromium carbide coatings for foil gas bearings to 650 C

    NASA Technical Reports Server (NTRS)

    Wagner, R. C.; Sliney, Harold E.

    1986-01-01

    A new self-lubricating coating composition of nickel aluminide-bonded chromium carbide formulated with silver and Group II fluorides was developed in a research program on high temperature solid lubricants. One of the proposed applications for this new coating composition is as a wide temperature spectrum solid lubricant for complaint foil gas bearings. Friction and wear properties were obtained using a foil gas bearing start-stop apparatus at temperatures from 25 to 650 C. The journals were Inconel 748. Some were coated with the plasma sprayed experimental coating, others with unmodified nickel aluminide/chromium carbide as a baseline for comparison. The additional components were provided to assist in achieving low friction over the temperature range of interest. Uncoated, preoxidized Inconel X-750 foil bearings were operated against these surfaces. The foils were subjected to repeated start/stop cycles under a 14-kPa (2-Psi) bearing unit loading. Sliding contact occurred during lift-off and coastdown at surface velocities less than 6 m/s (3000 rPm). Testing continued until 9000 start/stop cycles were accumulated or until a rise in starting torque indicated the journal/bearing had failed. Comparison in coating performance as well as discussions of their properties and methods of application are given.

  18. Effects of silver and group 2 fluorides addition to plasma sprayed chromium carbide high temperature solid lubricant for foil gas bearing to 650 deg C

    NASA Technical Reports Server (NTRS)

    Wagner, R. C.; Sliney, H. E.

    1984-01-01

    A new self-lubricating coating composition of nickel aluminide-bonded chromium carbide formulated with silver and Group II fluorides was developed in a research program on high temperature solid lubricants. One of the proposed applications for this new coating composition is as a wide temperature spectrum solid lubricant for complaint foil gas bearings. Friction and wear properties were obtained using a foil gas bearing start/stop apparatus at temperatures from 25 to 650 C. The journals were Inconel 718. Some were coated with the plasma sprayed experimental coating, others with unmodified nickel aluminide/chromium carbide as a baseline for comparison. The addtitional components were provided to assist in achieving low friction over the temperature range of interest. Uncoated, preoxidized Inconel X-750 foil bearings were operated against these surfaces. The foils were subjected to repeated start/stop cycles under a 14-kPa (2-psi) bearing unit loading. Sliding contact occurred during lift-off and coastdown at surface velocities less than 6 m/s (3000 rpm). Testing continued until 9000 start/stop cycles were accumulated or until a rise in starting torque indicated the journal/bearing had failed. Comparison in coating performance as well as discussions of their properties and methods of application are given.

  19. Facile one-step synthesis of highly branched ZnO nanostructures on titanium foil for flexible dye-sensitized solar cells.

    PubMed

    Zhang, Juntao; He, Meng; Fu, Nianqing; Li, Jianye; Yin, Xiong

    2014-04-21

    Highly branched ZnO (HBZ) nanostructures were prepared on titanium (Ti) foil using a facile, one-step vapor confined chemical vapor deposition technique. The as-prepared ZnO layer showed a good connection with the Ti foil even after 50 bending cycles, and the resultant HBZ/Ti electrode possessed high bendability. The HBZ/Ti electrode was composed of four different layers, including a highly branched ZnO layer, a ZnO compact layer, a Ti-Zn alloy layer and Ti foil. The good adhesion of the as-prepared ZnO layer to Ti foil was ascribed to the formation of a Ti-Zn alloy layer and a ZnO compact layer during the growth process. A flexible dye-sensitized solar cell was assembled using the D149-sensitized HBZ/Ti as a photoanode, and a power conversion efficiency (PCE) of 3.3% was achieved with an open-circuit photovoltage of 0.664 V, a short-circuit current density of 7.53 mA cm(-2), and a fill factor of 0.66 measured under rear-side illumination (AM 1.5, 100 mW cm(-2)). The power conversion efficiency of the device remained at 92% of the initial value even after 50 bending cycles. These results indicate that the vapor confined chemical vapor deposition method which does not necessarily use any catalyst or seed is a facile, one-step approach to obtain highly branched ZnO nanostructures with high bendability on Ti foil. The tight bonding between the highly branched ZnO layer and Ti substrate by a Ti-Zn alloy layer and a ZnO compact layer makes the vapor confined CVD method very attractive for the preparation of high-performance flexible photoanodes.

  20. Facile one-step synthesis of highly branched ZnO nanostructures on titanium foil for flexible dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Zhang, Juntao; He, Meng; Fu, Nianqing; Li, Jianye; Yin, Xiong

    2014-03-01

    Highly branched ZnO (HBZ) nanostructures were prepared on titanium (Ti) foil using a facile, one-step vapor confined chemical vapor deposition technique. The as-prepared ZnO layer showed a good connection with the Ti foil even after 50 bending cycles, and the resultant HBZ/Ti electrode possessed high bendability. The HBZ/Ti electrode was composed of four different layers, including a highly branched ZnO layer, a ZnO compact layer, a Ti-Zn alloy layer and Ti foil. The good adhesion of the as-prepared ZnO layer to Ti foil was ascribed to the formation of a Ti-Zn alloy layer and a ZnO compact layer during the growth process. A flexible dye-sensitized solar cell was assembled using the D149-sensitized HBZ/Ti as a photoanode, and a power conversion efficiency (PCE) of 3.3% was achieved with an open-circuit photovoltage of 0.664 V, a short-circuit current density of 7.53 mA cm-2, and a fill factor of 0.66 measured under rear-side illumination (AM 1.5, 100 mW cm-2). The power conversion efficiency of the device remained at 92% of the initial value even after 50 bending cycles. These results indicate that the vapor confined chemical vapor deposition method which does not necessarily use any catalyst or seed is a facile, one-step approach to obtain highly branched ZnO nanostructures with high bendability on Ti foil. The tight bonding between the highly branched ZnO layer and Ti substrate by a Ti-Zn alloy layer and a ZnO compact layer makes the vapor confined CVD method very attractive for the preparation of high-performance flexible photoanodes.

  1. Influence of cooking methods on antioxidant activity of vegetables.

    PubMed

    Jiménez-Monreal, A M; García-Diz, L; Martínez-Tomé, M; Mariscal, M; Murcia, M A

    2009-04-01

    The influence of home cooking methods (boiling, microwaving, pressure-cooking, griddling, frying, and baking) on the antioxidant activity of vegetables has been evaluated in 20 vegetables, using different antioxidant activity assays (lipoperoxyl and hydroxyl radicals scavenging and TEAC). Artichoke was the only vegetable that kept its very high scavenging-lipoperoxyl radical capacity in all the cooking methods. The highest losses of LOO. scavenging capacity were observed in cauliflower after boiling and microwaving, pea after boiling, and zucchini after boiling and frying. Beetroot, green bean, and garlic kept their antioxidant activity after most cooking treatments. Swiss chard and pepper lost OH. scavenging capacity in all the processes. Celery increased its antioxidant capacity in all the cooking methods, except boiling when it lost 14%. Analysis of the ABTS radical scavenging capacity of the different vegetables showed that the highest losses occurred in garlic with all the methods, except microwaving. Among the vegetables that increased their TEAC values were green bean, celery, and carrot after all cooking methods (except green bean after boiling). These 3 types of vegetables showed a low ABTS radical scavenging capacity. According to the method of analysis chosen, griddling, microwave cooking, and baking alternately produce the lowest losses, while pressure-cooking and boiling lead to the greatest losses; frying occupies an intermediate position. In short, water is not the cook's best friend when it comes to preparing vegetables.

  2. A method for measuring total thiaminase activity in fish tissues

    USGS Publications Warehouse

    Zajicek, James L.; Tillitt, Donald E.; Honeyfield, Dale C.; Brown, Scott B.; Fitzsimons, John D.

    2005-01-01

    An accurate, quantitative, and rapid method for the measurement of thiaminase activity in fish samples is required to provide sufficient information to characterize the role of dietary thiaminase in the onset of thiamine deficiency in Great Lakes salmonines. A radiometric method that uses 14C-thiamine was optimized for substrate and co-substrate (nicotinic acid) concentrations, incubation time, and sample dilution. Total thiaminase activity was successfully determined in extracts of selected Great Lakes fishes and invertebrates. Samples included whole-body and selected tissues of forage fishes. Positive control material prepared from frozen alewives Alosa pseudoharengus collected in Lake Michigan enhanced the development and application of the method. The method allowed improved discrimination of thiaminolytic activity among forage fish species and their tissues. The temperature dependence of the thiaminase activity observed in crude extracts of Lake Michigan alewives followed a Q10 = 2 relationship for the 1-37??C temperature range, which is consistent with the bacterial-derived thiaminase I protein. ?? Copyright by the American Fisheries Society 2005.

  3. Low-Threshold Active Teaching Methods for Mathematic Instruction

    ERIC Educational Resources Information Center

    Marotta, Sebastian M.; Hargis, Jace

    2011-01-01

    In this article, we present a large list of low-threshold active teaching methods categorized so the instructor can efficiently access and target the deployment of conceptually based lessons. The categories include teaching strategies for lecture on large and small class sizes; student action individually, in pairs, and groups; games; interaction…

  4. Background and Source Term Identification in Active Neutron Interrogation Methods

    DTIC Science & Technology

    2011-03-24

    low MeV neutron energy range, the increased numbers of neutrons from scattering ...reactions for low neutron energy . For U-235, low energy neutrons (thermal neutrons ) are more likely to cause fission than inelastic scattering or...manner. Active neutron interrogation is a sought after method for this since the resulting high energy gamma rays produced by inelastic scattering

  5. An Experimental Method for the Active Learning of Greedy Algorithms

    ERIC Educational Resources Information Center

    Velazquez-Iturbide, J. Angel

    2013-01-01

    Greedy algorithms constitute an apparently simple algorithm design technique, but its learning goals are not simple to achieve.We present a didacticmethod aimed at promoting active learning of greedy algorithms. The method is focused on the concept of selection function, and is based on explicit learning goals. It mainly consists of an…

  6. Optical design and active optics methods in astronomy

    NASA Astrophysics Data System (ADS)

    Lemaitre, Gerard R.

    2013-03-01

    Optical designs for astronomy involve implementation of active optics and adaptive optics from X-ray to the infrared. Developments and results of active optics methods for telescopes, spectrographs and coronagraph planet finders are presented. The high accuracy and remarkable smoothness of surfaces generated by active optics methods also allow elaborating new optical design types with high aspheric and/or non-axisymmetric surfaces. Depending on the goal and performance requested for a deformable optical surface analytical investigations are carried out with one of the various facets of elasticity theory: small deformation thin plate theory, large deformation thin plate theory, shallow spherical shell theory, weakly conical shell theory. The resulting thickness distribution and associated bending force boundaries can be refined further with finite element analysis.

  7. Gas Electron Multiplier foil holes: a study of mechanical and deformation effects

    NASA Astrophysics Data System (ADS)

    Benussi, L.; Bianco, S.; Saviano, G.; Muhammad, S.; Piccolo, D.; Suhaj, A.; Sharma, A.; Caponero, M.; Passamonti, L.; Pierluigi, D.; Russo, A.; Lalli, A.; Valente, M.; Ferrini, M.; Langeslag, S. A. E.; Sgobba, S.; Aviles, I.; Magnani, A.; Vai, I.

    2016-08-01

    The GEM detectors will be installed at the Compact Muon Solenoid (CMS) experiment during Long Shutdown II of the LHC in 2018. The GEM foil is a basic part of the detector which consists of a composite material, i.e. polyimide coated with copper and perforated with a high density of micro holes. In this paper the results of the GEM foil material characterization are reported, and a campaign of tensile and holes deformation tests is performed. During the tests, the complex radiation environment at CMS is taken into account and samples are prepared accordingly to see the impacts of the radiation on the GEM foil, i.e. non-irradiated samples are used as the reference and compared with neutrons- and gamma- irradiated. These studies provide the information necessary to optimize the stress level without damaging the foil and holes during the detector assembly in which the GEM foils stack is stretched simultaneously to maintain the uniform gap among the foils in order to get the designed performance of the detector. Finally, an estimate of the Young's modulus of the GEM foil is provided by using the tensile test data.

  8. An Assessment of Gas Foil Bearing Scalability and the Potential Benefits to Civilian Turbofan Engines

    NASA Technical Reports Server (NTRS)

    Bruckner, Robert J.

    2010-01-01

    Over the past several years the term oil-free turbomachinery has been used to describe a rotor support system for high speed turbomachinery that does not require oil for lubrication, damping, or cooling. The foundation technology for oil-free turbomachinery is the compliant foil bearing. This technology can replace the conventional rolling element bearings found in current engines. Two major benefits are realized with this technology. The primary benefit is the elimination of the oil lubrication system, accessory gearbox, tower shaft, and one turbine frame. These components account for 8 to 13 percent of the turbofan engine weight. The second benefit that compliant foil bearings offer to turbofan engines is the capability to operate at higher rotational speeds and shaft diameters. While traditional rolling element bearings have diminished life, reliability, and load capacity with increasing speeds, the foil bearing has a load capacity proportional to speed. The traditional applications for foil bearings have been in small, lightweight machines. However, recent advancements in the design and manufacturing of foil bearings have increased their potential size. An analysis, grounded in experimentally proven operation, is performed to assess the scalability of the modern foil bearing. This analysis was coupled to the requirements of civilian turbofan engines. The application of the foil bearing to larger, high bypass ratio engines nominally at the 120 kN (approx.25000 lb) thrust class has been examined. The application of this advanced technology to this system was found to reduce mission fuel burn by 3.05 percent.

  9. Adaptive Current Control Method for Hybrid Active Power Filter

    NASA Astrophysics Data System (ADS)

    Chau, Minh Thuyen

    2016-09-01

    This paper proposes an adaptive current control method for Hybrid Active Power Filter (HAPF). It consists of a fuzzy-neural controller, identification and prediction model and cost function. The fuzzy-neural controller parameters are adjusted according to the cost function minimum criteria. For this reason, the proposed control method has a capability on-line control clings to variation of the load harmonic currents. Compared to the single fuzzy logic control method, the proposed control method shows the advantages of better dynamic response, compensation error in steady-state is smaller, able to online control is better and harmonics cancelling is more effective. Simulation and experimental results have demonstrated the effectiveness of the proposed control method.

  10. A general method for determining secondary active transporter substrate stoichiometry.

    PubMed

    Fitzgerald, Gabriel A; Mulligan, Christopher; Mindell, Joseph A

    2017-01-25

    The number of ions required to drive substrate transport through a secondary active transporter determines the protein's ability to create a substrate gradient, a feature essential to its physiological function, and places fundamental constraints on the transporter's mechanism. Stoichiometry is known for a wide array of mammalian transporters, but, due to a lack of readily available tools, not for most of the prokaryotic transporters for which high-resolution structures are available. Here, we describe a general method for using radiolabeled substrate flux assays to determine coupling stoichiometries of electrogenic secondary active transporters reconstituted in proteoliposomes by measuring transporter equilibrium potentials. We demonstrate the utility of this method by determining the coupling stoichiometry of VcINDY, a bacterial Na(+)-coupled succinate transporter, and further validate it by confirming the coupling stoichiometry of vSGLT, a bacterial sugar transporter. This robust thermodynamic method should be especially useful in probing the mechanisms of transporters with available structures.

  11. Physical Activity Recognition with Mobile Phones: Challenges, Methods, and Applications

    NASA Astrophysics Data System (ADS)

    Yang, Jun; Lu, Hong; Liu, Zhigang; Boda, Péter Pál

    In this book chapter, we present a novel system that recognizes and records the physical activity of a person using a mobile phone. The sensor data is collected by built-in accelerometer sensor that measures the motion intensity of the device. The system recognizes five everyday activities in real-time, i.e., stationary, walking, running, bicycling, and in vehicle. We first introduce the sensor's data format, sensor calibration, signal projection, feature extraction, and selection methods. Then we have a detailed discussion and comparison of different choices of feature sets and classifiers. The design and implementation of one prototype system is presented along with resource and performance benchmark on Nokia N95 platform. Results show high recognition accuracies for distinguishing the five activities. The last part of the chapter introduces one demo application built on top of our system, physical activity diary, and a selection of potential applications in mobile wellness, mobile social sharing and contextual user interface domains.

  12. Toxin activity assays, devices, methods and systems therefor

    DOEpatents

    Koh, Chung-Yan; Schaff, Ulrich Y.; Sommer, Gregory Jon

    2016-04-05

    Embodiments of the present invention are directed toward devices, system and method for conducting toxin activity assay using sedimentation. The toxin activity assay may include generating complexes which bind to a plurality of beads in a fluid sample. The complexes may include a target toxin and a labeling agent, or may be generated due to presence of active target toxin and/or labeling agent designed to be incorporated into complexes responsive to the presence of target active toxin. The plurality of beads including the complexes may be transported through a density media, wherein the density media has a lower density than a density of the beads and higher than a density of the fluid sample, and wherein the transporting occurs, at least in part, by sedimentation. Signal may be detected from the labeling agents of the complexes.

  13. Methods of increasing secretion of polypeptides having biological activity

    SciTech Connect

    Merino, Sandra

    2013-10-01

    The present invention relates to methods for producing a secreted polypeptide having biological activity, comprising: (a) transforming a fungal host cell with a fusion protein construct encoding a fusion protein, which comprises: (i) a first polynucleotide encoding a signal peptide; (ii) a second polynucleotide encoding at least a catalytic domain of an endoglucanase or a portion thereof; and (iii) a third polynucleotide encoding at least a catalytic domain of a polypeptide having biological activity; wherein the signal peptide and at least the catalytic domain of the endoglucanase increases secretion of the polypeptide having biological activity compared to the absence of at least the catalytic domain of the endoglucanase; (b) cultivating the transformed fungal host cell under conditions suitable for production of the fusion protein; and (c) recovering the fusion protein, a component thereof, or a combination thereof, having biological activity, from the cultivation medium.

  14. Methods of increasing secretion of polypeptides having biological activity

    DOEpatents

    Merino, Sandra

    2014-10-28

    The present invention relates to methods for producing a secreted polypeptide having biological activity, comprising: (a) transforming a fungal host cell with a fusion protein construct encoding a fusion protein, which comprises: (i) a first polynucleotide encoding a signal peptide; (ii) a second polynucleotide encoding at least a catalytic domain of an endoglucanase or a portion thereof; and (iii) a third polynucleotide encoding at least a catalytic domain of a polypeptide having biological activity; wherein the signal peptide and at least the catalytic domain of the endoglucanase increases secretion of the polypeptide having biological activity compared to the absence of at least the catalytic domain of the endoglucanase; (b) cultivating the transformed fungal host cell under conditions suitable for production of the fusion protein; and (c) recovering the fusion protein, a component thereof, or a combination thereof, having biological activity, from the cultivation medium.

  15. Methods of increasing secretion of polypeptides having biological activity

    DOEpatents

    Merino, Sandra

    2014-05-27

    The present invention relates to methods for producing a secreted polypeptide having biological activity, comprising: (a) transforming a fungal host cell with a fusion protein construct encoding a fusion protein, which comprises: (i) a first polynucleotide encoding a signal peptide; (ii) a second polynucleotide encoding at least a catalytic domain of an endoglucanase or a portion thereof; and (iii) a third polynucleotide encoding at least a catalytic domain of a polypeptide having biological activity; wherein the signal peptide and at least the catalytic domain of the endoglucanase increases secretion of the polypeptide having biological activity compared to the absence of at least the catalytic domain of the endoglucanase; (b) cultivating the transformed fungal host cell under conditions suitable for production of the fusion protein; and (c) recovering the fusion protein, a component thereof, or a combination thereof, having biological activity, from the cultivation medium.

  16. Methods of increasing secretion of polypeptides having biological activity

    SciTech Connect

    Merino, Sandra

    2015-04-14

    The present invention relates to methods for producing a secreted polypeptide having biological activity, comprising: (a) transforming a fungal host cell with a fusion protein construct encoding a fusion protein, which comprises: (i) a first polynucleotide encoding a signal peptide; (ii) a second polynucleotide encoding at least a catalytic domain of an endoglucanase or a portion thereof; and (iii) a third polynucleotide encoding at least a catalytic domain of a polypeptide having biological activity; wherein the signal peptide and at least the catalytic domain of the endoglucanase increases secretion of the polypeptide having biological activity compared to the absence of at least the catalytic domain of the endoglucanase; (b) cultivating the transformed fungal host cell under conditions suitable for production of the fusion protein; and (c) recovering the fusion protein, a component thereof, or a combination thereof, having biological activity, from the cultivation medium.

  17. Performance variation due to stiffness in a tuna-inspired flexible foil model.

    PubMed

    Rosic, Mariel-Luisa N; Thornycroft, Patrick J M; Feilich, Kara L; Lucas, Kelsey N; Lauder, George V

    2017-01-17

    Tuna are fast, economical swimmers in part due to their stiff, high aspect ratio caudal fins and streamlined bodies. Previous studies using passive caudal fin models have suggested that while high aspect ratio tail shapes such as a tuna's generally perform well, tail performance cannot be determined from shape alone. In this study, we analyzed the swimming performance of tuna-tail-shaped hydrofoils of a wide range of stiffnesses, heave amplitudes, and frequencies to determine how stiffness and kinematics affect multiple swimming performance parameters for a single foil shape. We then compared the foil models' kinematics with published data from a live swimming tuna to determine how well the hydrofoil models could mimic fish kinematics. Foil kinematics over a wide range of motion programs generally showed a minimum lateral displacement at the narrowest part of the foil, and, immediately anterior to that, a local area of large lateral body displacement. These two kinematic patterns may enhance thrust in foils of intermediate stiffness. Stiffness and kinematics exhibited subtle interacting effects on hydrodynamic efficiency, with no one stiffness maximizing both thrust and efficiency. Foils of intermediate stiffnesses typically had the greatest coefficients of thrust at the highest heave amplitudes and frequencies. The comparison of foil kinematics with tuna kinematics showed that tuna motion is better approximated by a zero angle of attack foil motion program than by programs that do not incorporate pitch. These results indicate that open questions in biomechanics may be well served by foil models, given appropriate choice of model characteristics and control programs. Accurate replication of biological movements will require refinement of motion control programs and physical models, including the creation of models of variable stiffness.

  18. [Development and optimization of the methods for determining activity of plasminogen activator inhibitor-1 in plasma].

    PubMed

    Roka-Moĭia, Ia M; Zhernosiekov, D D; Kondratiuk, A S; Hrynenko, T V

    2013-01-01

    The activity and content of plasminogen activator inhibitor-1 (PAI-1) are important indicators of pathological processes, because its content in plasma increases at acute myocardium infarction, tumor, diabetes mellitus, etc. The present work is dedicated to the development and optimization of the methods of PAI-1 activity definition, which can be used in clinical practice. We have proposed the modification of the method COATEST PAI with the usage of chromogenic substrate S2251. According to our modification, the cyanogen bromide fragments of human fibrinogen have been changed into bovine desAB-fibrin. We have also developed the method with the usage of fibrin films. In this method fibrin is used as a stimulator of activation reaction and as a substrate at the same time. Using fibrin, the native substrate of plasmin, we provide high specificity of the reaction and exclude the cross-reaction with other plasma enzymes.

  19. Synthetic Methods, Chemistry, and the Anticonvulsant Activity of Thiadiazoles

    PubMed Central

    Sharma, Bhawna; Verma, Amita; Prajapati, Sunil; Sharma, Upendra Kumar

    2013-01-01

    The chemistry of heterocyclic compounds has been an interesting field of study for a long time. Heterocyclic nucleus 1,3,4-thiadiazole constitutes an important class of compounds for new drug development. The synthesis of novel thiadiazole derivatives and investigation of their chemical and biological behavior have gained more importance in recent decades. The search for antiepileptic compounds with more selective activity and lower toxicity continues to be an active area of intensive investigation in medicinal chemistry. During the recent years, there has been intense investigation of different classes of thiadiazole compounds, many of which possess extensive pharmacological activities, namely, antimicrobial activity, anticonvulsant, antifungal antidiabetic, anti-inflammatory, antioxidant, and antituberculosis activities, and so forth. The resistance towards available drugs is rapidly becoming a major worldwide problem. The need to design new compounds to deal with this resistance has become one of the most important areas of research today. Thiadiazole is a versatile moiety that exhibits a wide variety of biological activities. Thiadiazole moiety acts as “hydrogen binding domain” and “two-electron donor system.” It also acts as a constrained pharmacophore. On the basis of the reported literature, we study here thiadiazole compounds and their synthetic methods chemistry and anticonvulsant activity. PMID:25405032

  20. Soft-tissues Image Processing: Comparison of Traditional Segmentation Methods with 2D active Contour Methods

    NASA Astrophysics Data System (ADS)

    Mikulka, J.; Gescheidtova, E.; Bartusek, K.

    2012-01-01

    The paper deals with modern methods of image processing, especially image segmentation, classification and evaluation of parameters. It focuses primarily on processing medical images of soft tissues obtained by magnetic resonance tomography (MR). It is easy to describe edges of the sought objects using segmented images. The edges found can be useful for further processing of monitored object such as calculating the perimeter, surface and volume evaluation or even three-dimensional shape reconstruction. The proposed solutions can be used for the classification of healthy/unhealthy tissues in MR or other imaging. Application examples of the proposed segmentation methods are shown. Research in the area of image segmentation focuses on methods based on solving partial differential equations. This is a modern method for image processing, often called the active contour method. It is of great advantage in the segmentation of real images degraded by noise with fuzzy edges and transitions between objects. In the paper, results of the segmentation of medical images by the active contour method are compared with results of the segmentation by other existing methods. Experimental applications which demonstrate the very good properties of the active contour method are given.

  1. Suppression of instability by double ablation in tungsten doped polyvinyl alcohol foils

    NASA Astrophysics Data System (ADS)

    Peedikakkandy, Leshma; Chaurasia, S.

    2012-07-01

    In Inertial fusion Energy (IFE) research stable acceleration of fusion targets is a significant problem due to hydrodynamic instabilities. This paper presents the results of the experiments done to investigate the effects of doping 20% of Tungsten (W) (by weight) in Polyvinyl Alcohol (PVA) polymer foils for suppression of instability during laser ablative acceleration. A 20J, 1.060μm, 900ps, Nd: Glass laser system with a focusable intensity of 3 to 9.6×1013W/cm2 was used in the experiment. It is observed that the doped PVA targets yielded stable and enhanced foil acceleration as compared to the undoped PVA foils.

  2. Structural changes on the surface of tungsten foils under uniaxial tension

    NASA Astrophysics Data System (ADS)

    Korsukov, V. E.; Knyazev, S. A.; Butenko, P. N.; Gilyarov, V. L.; Korsukova, M. M.; Nyapshaev, I. A.; Obidov, B. A.

    2017-02-01

    A change in the surface morphology of recrystallized tungsten foil under the effect of uniaxial tension in ultrahigh vacuum is studied by low-energy electron diffraction and atomic force microscopy. It is found by using low-energy electron diffraction that on the foil surface consisting of separate blocks with dominant face (112), there is a turn in orientation of the structural blocks. The analysis of the topograms of different areas of the side surface of a broken sample, obtained by atomic force microscopy, enabled the association of changes in the atomic structure of the surface layers of foil with a change in its relief by mechanical action.

  3. Thermally-induced stresses in graphite-epoxy tubes coated with aluminum foil

    NASA Technical Reports Server (NTRS)

    Knott, Tamara W.; Hyer, M. W.

    1989-01-01

    Thermally-induced stresses in the foil, adhesive, and graphite-epoxy layers of composite tubes with aluminum foil bonded to the inner and outer surface are computed. The thermal effects are due to a temperature decrease from the processing temperature of the material to a temperature felt to represent the space environment, the intended operating environment of the tubes. Tubes fabricated from T300/934 and P75s/934 material systems are considered. The results indicate that the presence of the foil and adhesive have no detrimental effect on the stresses in the tube.

  4. Interaction of solar wind ions with thin carbon foils: Calibration of time-of-flight spectrometers

    NASA Astrophysics Data System (ADS)

    Gonin, M.; Buergi, Alfred; Oetliker, M.; Bochsler, P.

    1992-11-01

    With the KAFKA (German acronym for carbon foils collisions analyzer) experiment, charge exchange, energy loss and angular scattering of solar wind ions in thin (1 to 10 microg/sq cm) carbon foils, are studied. Such foils are extensively used in time of flight mass spectrometry. So far, the properties of H, He, B, C, N, O, F, Ne, Na, Mg, Al, Si, S, Cl, Ar, K, Ti, Fe, and Ni and in the 0.5 to 5 keV/u energy range have been investigated.

  5. Formation and evolution of tweed structures on high-purity aluminum polycrystalline foils under cyclic tension

    SciTech Connect

    Kuznetsov, P. V.; Vlasov, I. V.; Sklyarova, E. A.; Smekalina, T. V.

    2015-10-27

    Peculiarities of formation and evolution of tweed structures on the surface of high-purity aluminum polycrystalline foils under cyclic tension were studied using an atom force microscope and a white light interferometer. Tweed structures of micron and submicron sizes were found on the foils at different number of cycles. In the range of 42,000 < N < 95,000 cycles destruction of tweed patterns is observed, which leads to their disappearance from the surface of the foils. Formation of tweed structures of various scales is discussed in terms of the Grinfeld instability.

  6. Shock compression response of highly reactive Ni + Al multilayered thin foils

    NASA Astrophysics Data System (ADS)

    Kelly, Sean C.; Thadhani, Naresh N.

    2016-03-01

    The shock-compression response of Ni + Al multilayered thin foils is investigated using laser-accelerated thin-foil plate-impact experiments over the pressure range of 2 to 11 GPa. The foils contain alternating Ni and Al layers (parallel but not flat) of nominally 50 nm bilayer spacing. The goal is to determine the equation of state and shock-induced reactivity of these highly reactive fully dense thin-foil materials. The laser-accelerated thin-foil impact set-up involved combined use of photon-doppler-velocimetry to monitor the acceleration and impact velocity of an aluminum flyer, and VISAR interferometry was used to monitor the back free-surface velocity of the impacted Ni + Al multilayered target. The shock-compression response of the Ni + Al target foils was determined using experimentally measured parameters and impedance matching approach, with error bars identified considering systematic and experimental errors. Meso-scale CTH shock simulations were performed using real imported microstructures of the cross-sections of the multilayered Ni + Al foils to compute the Hugoniot response (assuming no reaction) for correlation with their experimentally determined equation of state. It was observed that at particle velocities below ˜150 m/s, the experimentally determined equation of state trend matches the CTH-predicted inert response and is consistent with the observed unreacted state of the recovered Ni + Al target foils from this velocity regime. At higher particle velocities, the experimentally determined equation of state deviates from the CTH-predicted inert response. A complete and self-sustained reaction is also seen in targets recovered from experiments performed at these higher particle velocities. The deviation in the measured equation of state, to higher shock speeds and expanded volumes, combined with the observation of complete reaction in the recovered multilayered foils, confirmed via microstructure characterization, is indicative of the occurrence

  7. Quench Protection System based on Active Power Method

    NASA Astrophysics Data System (ADS)

    Nanato, Nozomu

    In superconducting coils, local and excessive joule heating may give damage to the superconducting windings when a quench occurs and therefore it is essential that the quench is detected quickly and precisely so that the coils can be safely discharged. We have presented a quench protection system based on the active power method which detects a quench by measuring the instantaneous active power generated in a superconducting coil. The protection system based on this method is strong against the inductive voltage and noise which may cause insufficient quench recognition. However, the proposed system is useful for a single coil but it is vulnerable to the magnetically coupled multi-coil such as high field superconducting coils. Because the proposed system can not avoid insufficient quench recognition by the mutual inductive voltage from the other coils. This paper presents a method to improve the characteristics of the active power method by cancelling the mutual inductive voltage. The experimental results of the quench protection for small Bi2223 coils show that the proposed system is useful for the magnetically coupled coils.

  8. Evaluation of pozzolanic activity by the electric resistance measurement method

    SciTech Connect

    Tashiro, Chuichi; Ikeda, Ko . Dept. of Advanced Materials Science and Engineering); Inoue, Yoshihiro )

    1994-01-01

    Measurements of electric resistance and amount of consumption of portlandite were carried out in accelerated curing conditions by preparing pastes of Fine Ceraments, fly ash, silica fume, kaolin, acid clay, zeolite and quartz activated with portlandite. Electric resistances of reactive pozzolans showed sharp rises except that of kaolin, whereas that of inactive material, quartz, showed no sharp rise. Electric resistances are proportional to the consumptions of portlandite except for fly ashes. The electric resistance measurement method combined with portlandite consumption measurement is useful to the rapid evaluation of pozzolanic activity.

  9. Iron active electrode and method of making same

    DOEpatents

    Jackovitz, John F.; Seidel, Joseph; Pantier, Earl A.

    1982-10-26

    An iron active electrode and method of preparing same in which iron sulfate is calcined in an oxidizing atmosphere at a temperature in the range of from about 600.degree. C. to about 850.degree. C. for a time sufficient to produce an iron oxide with a trace amount of sulfate. The calcined material is loaded into an electrically conductive support and then heated in a reducing atmosphere at an elevated temperature to produce activated iron having a trace amount of sulfide which is formed into an electrode plate.

  10. Experimental neutronics tests for a neutron activation system for the European ITER TBM

    SciTech Connect

    Klix, A.; Fischer, U.; Gehre, D.; Kleizer, G.; Raj, P.; Rovni, I.; Ruecker, Tom

    2014-08-21

    We are investigating methods for neutron flux measurement in the ITER TBM. In particular we have tested sets of activation materials leading to induced gamma activities with short half-lives of the order of tens of seconds up to minutes and standard activation materials. Packages of activation foils have been irradiated with the intense neutron generator of Technical University of Dresden in a pure DT neutron field as well as in a neutronics mock-up of the European ITER HCLL TBM. An important aim was to check whether the gamma activity induced in the activation foils in these packages could be measured simultaneously. It was indeed possible to identify gamma lines of interest in gamma-ray measurements immediately after extraction from the irradiation.

  11. Estimation of Organ Activity using Four Different Methods of Background Correction in Conjugate View Method

    PubMed Central

    Shanei, Ahmad; Afshin, Maryam; Moslehi, Masoud; Rastaghi, Sedighe

    2015-01-01

    To make an accurate estimation of the uptake of radioactivity in an organ using the conjugate view method, corrections of physical factors, such as background activity, scatter, and attenuation are needed. The aim of this study was to evaluate the accuracy of four different methods for background correction in activity quantification of the heart in myocardial perfusion scans. The organ activity was calculated using the conjugate view method. A number of 22 healthy volunteers were injected with 17–19 mCi of 99mTc-methoxy-isobutyl-isonitrile (MIBI) at rest or during exercise. Images were obtained by a dual-headed gamma camera. Four methods for background correction were applied: (1) Conventional correction (referred to as the Gates' method), (2) Buijs method, (3) BgdA subtraction, (4) BgdB subtraction. To evaluate the accuracy of these methods, the results of the calculations using the above-mentioned methods were compared with the reference results. The calculated uptake in the heart using conventional method, Buijs method, BgdA subtraction, and BgdB subtraction methods was 1.4 ± 0.7% (P < 0.05), 2.6 ± 0.6% (P < 0.05), 1.3 ± 0.5% (P < 0.05), and 0.8 ± 0.3% (P < 0.05) of injected dose (I.D) at rest and 1.8 ± 0.6% (P > 0.05), 3.1 ± 0.8% (P > 0.05), 1.9 ± 0.8% (P < 0.05), and 1.2 ± 0.5% (P < 0.05) of I.D, during exercise. The mean estimated myocardial uptake of 99mTc-MIBI was dependent on the correction method used. Comparison among the four different methods of background activity correction applied in this study showed that the Buijs method was the most suitable method for background correction in myocardial perfusion scan. PMID:26955568

  12. Estimation of Organ Activity using Four Different Methods of Background Correction in Conjugate View Method.

    PubMed

    Shanei, Ahmad; Afshin, Maryam; Moslehi, Masoud; Rastaghi, Sedighe

    2015-01-01

    To make an accurate estimation of the uptake of radioactivity in an organ using the conjugate view method, corrections of physical factors, such as background activity, scatter, and attenuation are needed. The aim of this study was to evaluate the accuracy of four different methods for background correction in activity quantification of the heart in myocardial perfusion scans. The organ activity was calculated using the conjugate view method. A number of 22 healthy volunteers were injected with 17-19 mCi of (99m)Tc-methoxy-isobutyl-isonitrile (MIBI) at rest or during exercise. Images were obtained by a dual-headed gamma camera. Four methods for background correction were applied: (1) Conventional correction (referred to as the Gates' method), (2) Buijs method, (3) BgdA subtraction, (4) BgdB subtraction. To evaluate the accuracy of these methods, the results of the calculations using the above-mentioned methods were compared with the reference results. The calculated uptake in the heart using conventional method, Buijs method, BgdA subtraction, and BgdB subtraction methods was 1.4 ± 0.7% (P < 0.05), 2.6 ± 0.6% (P < 0.05), 1.3 ± 0.5% (P < 0.05), and 0.8 ± 0.3% (P < 0.05) of injected dose (I.D) at rest and 1.8 ± 0.6% (P > 0.05), 3.1 ± 0.8% (P > 0.05), 1.9 ± 0.8% (P < 0.05), and 1.2 ± 0.5% (P < 0.05) of I.D, during exercise. The mean estimated myocardial uptake of (99m)Tc-MIBI was dependent on the correction method used. Comparison among the four different methods of background activity correction applied in this study showed that the Buijs method was the most suitable method for background correction in myocardial perfusion scan.

  13. Development of advanced model catalysts: A study of catalysis over epitaxially grown titanium oxide films, palladium foils and platinum nano-particle arrays

    NASA Astrophysics Data System (ADS)

    Jacobs, Peter W.

    1997-11-01

    Titania overlayers were grown in two different ordered structures on Pt(111) as seen by Low Energy Electron Diffraction (LEED). Fully oxidized, films maintain the symmetry of top layer of the substrate and form a coincident 18.2 A unit cell. These overlayers could be grown in monolayer and multi-layer coverages. They are seen by X-Ray Photoelectron Spectroscopy (XPS) to have TiOsb2 stoichiometry. Above 400sp°C the oxide disproportionates and titanium migrates into the bulk to form an alloy. The LEED and XPS data are consistent with the model of a close-packed lattice of oxygen anions with titanium cations in the octahedral sites. Vacuum annealing above 600sp°C forms a partially reduced monolayer with the stoichiometry Tisb4Osb7. This overlayer does not have the symmetry of the substrate. The unit cell is given by the coincidence of the substrate lattice with a rectangular cell of 3.5 A x 4.2 A. Ion Scattering Spectroscopy data suggests the structure is formed upon creating oxygen vacancies. Ethane oxidation was performed over palladium foils under a wide range of reactant concentrations to produce COsb2, Hsb2O, CHsb4 and Csb2Hsb4. The foils required an initial activation period at high temperature (>400sp°C) under fuel rich reaction conditions. Methane and COsb2 displayed similar kinetics although methane was produced with ˜1/85spth the rate. Ethylene was a reaction intermediate and eventually converted to COsb2. Depending on their concentration, water and oxygen inhibited combustion. A mechanism consistent with the observed kinetics is proposed in which the rate determining step is ethyl formation on a Pd-PdO or PdO-PdO two-atom site. Electron Beam Lithography was used to fabricate nanometer-scale arrays of platinum particles on an oxidized silicon wafer. Low energy ion bombardment was used to clean the array, which was then active for ethylene hydrogenation with rates comparable to the literature. Thermal desorption experiments demonstrated the possibility of

  14. Photocardiography: a novel method for monitoring cardiac activity in fish.

    PubMed

    Yoshida, Masayuki; Hirano, Ruriko; Shima, Takao

    2009-05-01

    A non-invasive technique to monitor cardiac activity in small fish, such as goldfish, zebrafish, and medaka, is needed. In the present study, we developed photocardiography (PCG), a non-invasive optical method, to record cardiac activity in small fish. The method monitors changes in near-infrared light transmission through the heart using a phototransistor located outside the body. With this technique, heartbeats in fish of various sizes (14-218 mm) were stably recorded. PCG was applied to monitor the heartbeat during fear-related classical heart rate conditioning in goldfish wherein an electrical shock was used as an unconditioned stimulus. The heartbeats were continuously monitored, even when the beat coincided with the electrical shock, showing that PCG is robust even in an electrically noisy environment. This technique is particularly useful when monitoring the heartbeats of fish of small size or in the presence of ambient electrical noise, conditions in which the use of conventional electrocardiography (ECG) is difficult.

  15. Statistical methods for active pharmacovigilance, with applications to diabetes drugs.

    PubMed

    Zhuo, Lan; Farrell, Patrick J; McNair, Doug; Krewski, Daniel

    2014-01-01

    Pharmacovigilance aims to identify adverse drug reactions using postmarket surveillance data under real-world conditions of use. Unlike passive pharmacovigilance, which is based on largely voluntary (and hence incomplete) spontaneous reports of adverse drug reactions with limited information on patient characteristics, active pharmacovigilance is based on electronic health records containing detailed information about patient populations, thereby allowing consideration of modifying factors such as polypharmacy and comorbidity, as well as sociodemographic characteristics. With the present shift toward active pharmacovigilance, statistical methods capable of addressing the complexities of such data are needed. We describe four such methods here, and demonstrate their application in the analysis of a large retrospective cohort of diabetics taking anti-hyperglycemic medications that may increase the risk of adverse cardiovascular events.

  16. Method of preparing high specific activity platinum-195m

    SciTech Connect

    Mirzadeh, Saed; Du, Miting; Beets, Arnold L.; Knapp, Jr., Furn F.

    2004-06-15

    A method of preparing high-specific-activity .sup.195m Pt includes the steps of: exposing .sup.193 Ir to a flux of neutrons sufficient to convert a portion of the .sup.193 Ir to .sup.195m Pt to form an irradiated material; dissolving the irradiated material to form an intermediate solution comprising Ir and Pt; and separating the Pt from the Ir by cation exchange chromatography to produce .sup.195m Pt.

  17. Method for preparing high specific activity 177Lu

    DOEpatents

    Mirzadeh, Saed; Du, Miting; Beets, Arnold L.; Knapp, Jr., Furn F.

    2004-04-06

    A method of separating lutetium from a solution containing Lu and Yb, particularly reactor-produced .sup.177 Lu and .sup.177 Yb, includes the steps of: providing a chromatographic separation apparatus containing LN resin; loading the apparatus with a solution containing Lu and Yb; and eluting the apparatus to chromatographically separate the Lu and the Yb in order to produce high-specific-activity .sup.177 Yb.

  18. Tooth whitening and temperature rise with two bleaching activation methods

    NASA Astrophysics Data System (ADS)

    Abu-ElMagd, D. M.; El-Sayad, I. I.; Abd El-Gawad, L. M.

    2009-02-01

    Objectives: To measure the tooth whitening and the surface and intra-pulpal temperature increase in vitro on extracted upper human incisors after chemical, zoom light and diode laser activated bleaching. Materials and Methods: Thirty caries-free upper human incisors were selected. Teeth were divided into three equal groups according to the methods of activation of the bleaching agent (n=10). A whitening gel containing hydrogen peroxide was applied to the buccal surface of all teeth. Group I was bleached using chemically activated hydrogen peroxide gel. Group II was bleached with high intensity advanced power zoom activation light, for three applications of 15 min each. Group III was bleached with diode laser activation technique, where the teeth were irradiated with 2 watt diode laser for three applications of 30 sec each. Degree of whitening was assessed using an image analysis system, while temperature rise was recorded using a thermocouple on the external tooth surface and intrapulpal. Results: The degree of whitening increased significantly in all groups. However, the percentage of whitening was not statistically significantly different between the three groups. In addition, group II showed statistically significant higher mean rise in both surface and pulp temperatures than group I and group III. Conclusions: Chemical bleaching produces the same whitening effect as zoom AP light and laser, with no surface or pulpal temperature rise. Laser application is faster and produces less surface and pulp temperature increase than zoom AP light. Diode lasers used to activate bleaching gels are not considered dangerous to the vitality of dental pulps using power settings of 2W.

  19. Static and dynamic performances of refrigerant-lubricated foil bearings

    NASA Astrophysics Data System (ADS)

    Bouchehit, B.; Bou-Saïd, B.; Garcia, M.

    2016-08-01

    Gas bearings are successfully used over a large panel of turbo-machineries. Some of these systems run in controlled environments such as refrigerating gas. We present in this paper a theoretical and numerical model which consider the vapor/liquid lubricant transition, the laminar/turbulent flow transition and both temperature and viscosity 3D variations in the fluid and the solids for both static and dynamic situations. The foil deflection is considered using the Heshmat's approach. This model involves: the resolution of the generalized Reynolds equation for compressible fluids with 3D variable viscosity, the description of the turbulence effects by the phenomenological approach of Elrod, using a 3D eddy viscosity field, the resolution of a non-linear equation of state for the lubricant, able to describe the vapor/liquid transition and a local thermal approach to obtain a 3D estimation of the fluid temperature, thanks to the thin-film energy equation and an actualisation of the film thickness. The thermal effects in solids are also taken into account. Both static and dynamic behaviours of GFBs are analysed.

  20. Silicon oxide permeation barrier coating of PET bottles and foils

    NASA Astrophysics Data System (ADS)

    Steves, Simon; Deilmann, Michael; Awakowicz, Peter

    2009-10-01

    Modern packaging materials such as polyethylene terephthalate (PET) have displaced established materials in many areas of food and beverage packaging. Plastic packing materials offer are various advantages concerning production and handling. PET bottles for instance are non-breakable and lightweight compared to glass and metal containers. However, PET offers poor barrier properties against gas permeation. Therefore, the shelf live of packaged food is reduced. Permeation of gases can be reduced by depositing transparent plasma polymerized silicon oxide (SiOx) barrier coatings. A microwave (2.45 GHz) driven low pressure plasma reactor is developed based on a modified Plasmaline antenna to treat PET foils or bottles. To increase the barrier properties of the coatings furthermore a RF substrate bias (13.56 MHz) is applied. The composition of the coatings is analyzed by means of Fourier transform infrared (FTIR) spectroscopy regarding carbon and hydrogen content. Influence of gas phase composition and substrate bias on chemical composition of the coatings is discussed. A strong relation between barrier properties and film composition is found: good oxygen barriers are observed as carbon content is reduced and films become quartz-like. Regarding oxygen permeation a barrier improvement factor (BIF) of 70 is achieved.