The effect of copper pre-cleaning on graphene synthesis.

PubMed

Kim, Soo Min; Hsu, Allen; Lee, Yi-Hsien; Dresselhaus, Mildred; Palacios, Tomás; Kim, Ki Kang; Kong, Jing

2013-09-13

Copper foil is the most common substrate to synthesize monolayer graphene by chemical vapor deposition (CVD). The surface morphology and conditions of the copper foil can be very different depending on the various suppliers or different batches. These surface properties of copper strongly affect the growth behavior of graphene, thus rendering the growth conditions irreproducible when different batches of Cu foil are used. Furthermore, the quality of the graphene is severely affected as well. In this work, we report a facile method of copper pre-cleaning to improve the graphene quality and the reproducibility of the growth process. We found that the commercial Ni etchant (based on nitric acid) or nitric acid is the most effective cleaning agent among various acidic or basic solutions. The graphene grown on thus-treated copper surfaces is very clean and mostly monolayer when observed under scanning electron microscopy (SEM) and optical imaging, as compared to the graphene grown on untreated copper foil. Different batches (but with the same catalog number) of copper foil from Alfa Aesar Company were examined to explore the effect of copper pre-cleaning; consistent growth results were obtained when pre-cleaning was used. This method overcomes a commonly encountered problem in graphene growth and could become one of the standard protocols for preparing the copper foil substrate for growing graphene or other 2D materials.

Nanosecond laser-induced ablation and laser-induced shockwave structuring of polymer foils down to sub-μm patterns

NASA Astrophysics Data System (ADS)

Lorenz, P.; Bayer, L.; Ehrhardt, M.; Zimmer, K.; Engisch, L.

2015-03-01

Micro- and nanostructures exhibit a growing commercial interest where a fast, cost-effective, and large-area production is attainable. Laser methods have a great potential for the easy fabrication of surface structures into flexible polymer foils like polyimide (PI). In this study two different concepts for the structuring of polymer foils using a KrF excimer laser were tested and compared: the laser-induced ablation and the laser-induced shock wave structuring. The direct front side laser irradiation of these polymers allows the fabrication of different surface structures. For example: The low laser fluence treatment of PI results in nano-sized cone structures where the cone density can be controlled by the laser parameters. This allows inter alia the laser fabrication of microscopic QR code and high-resolution grey-tone images. Furthermore, the laser treatment of the front side of the polymer foil allows the rear side structuring due to a laserinduced shock wave. The resultant surface structures were analysed by optical and scanning electron microscopy (SEM) as well as white light interferometry (WLI).

Finding Interstellar Particle Impacts on Stardust Aluminium Foils: The Safe Handling, Imaging, and Analysis of Samples Containing Femtogram Residues

NASA Technical Reports Server (NTRS)

Kearsley, A. T.; Westphal, A. J.; Stadermann, F. J.; Armes, S. P.; Ball, A. D.; Borg, J.; Bridges, J. C.; Brownlee, D. E.; Burchell, M. J.; Chater, R. J.;

Enhanced Reduction of Graphene Oxide on Recyclable Cu Foils to Fabricate Graphene Films with Superior Thermal Conductivity

PubMed Central

Huang, Sheng-Yun; Zhao, Bo; Zhang, Kai; Yuen, Matthew M. F.; Xu, Jian-Bin; Fu, Xian-Zhu; Sun, Rong; Wong, Ching-Ping

2015-01-01

Large-area freestanding graphene films are facilely fabricated by reducing graphene oxide films on recyclable Cu foils in H2-containing atmosphere at high temperature. Cu might act as efficient catalysts for considerably improved reduction of graphene oxide according to the SEM, EDS, XRD, XPS, Raman and TGA results. Comparing to the graphene films with ~30 μm thickness reduced without Cu substrate at 900 °C, the thermal conductivity and electrical conductivity of graphene films reduced on Cu foils are enhanced about 140% to 902 Wm−1K−1 and 3.6 × 104 S/m, respectively. Moreover, the graphene films demonstrate superior thermal conductivity of ~1219 Wm−1K−1 as decreasing the thickness of films to ~10 μm. The graphene films also exhibit excellent mechanical properties and flexibility. PMID:26404674

Achromobacter xylosoxidans as a new microorganism strain colonizing high-density polyethylene as a key step to its biodegradation.

PubMed

Kowalczyk, Anna; Chyc, Marek; Ryszka, Przemysław; Latowski, Dariusz

2016-06-01

This study presents results of research on isolation new bacteria strain Achromobacter xylosoxidans able to effect on the structure of high-density polyethylene (HDPE), polymer resistant to degradation in environment. New strain of A. xylosoxidans PE-1 was isolated from the soil and identified by analysis of the 16S ribosome subunit coding sequences. The substance to be degraded was HDPE in the form of thin foil films. The foil samples were analyzed with Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR) as well as scanning electron microscope (SEM), and the results revealed degradation of chemical structure of HDPE. About 9 % loss of weight was also detected as a result of A. xylosoxidans PE-1 effect on HDPE foil. On the basis of comparative spectral analysis of the raw material before the bacteria treatment and the spectrum from a spectra database, it was assumed that the HDPE was the only source of carbon and energy for the microorganisms. No fillers or other additives used in the plastic processing were observed in HDPE before experiments. This is the first communication showing that A. xylosoxidans is able to modify chemical structure of HDPE, what was observed both on FTIR, in mass reduction of HDPE and SEM analysis. We also observed quite good growth of the bacteria also when the HDPE was the sole carbon source in the medium. These results prove that A. xylosoxidans is an organism worth applying in future HDPE biodegradation studies.

Simulation of FIB-SEM images for analysis of porous microstructures.

PubMed

Prill, Torben; Schladitz, Katja

2013-01-01

Focused ion beam nanotomography-scanning electron microscopy tomography yields high-quality three-dimensional images of materials microstructures at the nanometer scale combining serial sectioning using a focused ion beam with SEM. However, FIB-SEM tomography of highly porous media leads to shine-through artifacts preventing automatic segmentation of the solid component. We simulate the SEM process in order to generate synthetic FIB-SEM image data for developing and validating segmentation methods. Monte-Carlo techniques yield accurate results, but are too slow for the simulation of FIB-SEM tomography requiring hundreds of SEM images for one dataset alone. Nevertheless, a quasi-analytic description of the specimen and various acceleration techniques, including a track compression algorithm and an acceleration for the simulation of secondary electrons, cut down the computing time by orders of magnitude, allowing for the first time to simulate FIB-SEM tomography. © Wiley Periodicals, Inc.

An integration machine for the assembly of the x-ray optic units based on thin slumped glass foils for the IXO mission

NASA Astrophysics Data System (ADS)

Civitani, M. M.; Basso, S.; Bavdaz, M.; Citterio, O.; Conconi, P.; Gallieni, D.; Ghigo, M.; Martelli, F.; Pareschi, G.; Parodi, G.; Proserpio, L.; Sironi, G.; Spiga, D.; Tagliaferri, G.; Tintori, M.; Wille, E.; Zambra, A.

2011-09-01

The International X-ray Observatory (IXO) is a joint mission concept studied by the ESA, NASA, and JAXA space agencies. The main goal of the mission design is to achieve a large effective area (>2.5m2 at 1 keV) and a good angular resolution (5 arcsec HEW at 1 keV) at the same time. The Brera Astronomical Observatory - INAF, Italy), under the support of ESA, is developing a method for the realization of the X-Ray Optical Units, based on the use of slumped thin glass segments to form densely packed modules in a Wolter type I optical configuration. In order to reach the very challenging integration requirements, it has been developed an innovative assembly approach for aligning and mounting the IXO mirror segments. The method is based on the use of an integration mould for each foil. In particular the glass segment is forced to adhere to the integration mould in order to maintain the optimal figure without deformations until the integration of the foil in the stack is completed. In this way an active correction for major existing figure errors after slumping is also achieved. Moreover reinforcing ribs are used in order to connect the facets to each-other and to realize a robust monolithic stack of plates. In this paper we present the design, the development and the validation status of a special Integration Machine (IMA) that has been specifically developed to allow the integration of the Plate Pairs into prototypal X-Ray Optical Unit stacks.

Eu2+,Dy3+ codoped SrAl2O4 nanocrystalline phosphor for latent fingerprint detection in forensic applications

NASA Astrophysics Data System (ADS)

Sharma, Vishal; Das, Amrita; Kumar, Vinay

2016-01-01

In this work, europium and dysprosium doped strontium aluminate (SrAl2O4:Eu2+,Dy3+) nanophosphor is synthesized and its novel application for the detection of latent fingerprints on various contact surfaces is reported. The SrAl2O4:Eu2+,Dy3+ is synthesized using a combustion method and shows long-lasting afterglow luminescence. The powder particles are characterized using field emission scanning electron microscopy (FE-SEM), SEM-energy dispersive x-ray analysis, x-ray diffraction and photoluminescence spectrophotometry. The FE-SEM image analysis reveals that the nanoparticles are mostly 8-15 nm in size with an irregular spherical shape. This nano-structured powder was applied to fresh and aged fingerprints deposited on porous, semi-porous and non-porous contact surfaces, such as ordinary colored paper, glossy paper, glass, aluminum foil, a yellow foil chocolate wrapper, a soft drink can, a PET bottle, a compact disc and a computer mouse. The results are reproducible and show great sensitivity and high contrast in the developed fingermark regions on these surfaces. These nanophosphor particles also show a strong and long-lasting afterglow property, making them a suitable candidate for use as a fingerprint developing agent on luminescent and highly patterned surfaces. These kinds of powders have shown that they can remove the interference from background luminescence, which is not possible using ordinary luminescent fingerprinting powders.

Numerical and Experimental Studies on the Explosive Welding of Tungsten Foil to Copper

PubMed Central

Zhou, Qiang; Feng, Jianrui; Chen, Pengwan

2017-01-01

This work verifies that the W foil could be successfully welded on Cu through conventional explosive welding, without any cracks. The microstructure was observed through scanning electron microscopy (SEM), optical microscopy and energy-dispersive X-ray spectrometry (EDS). The W/Cu interface exhibited a wavy morphology, and no intermetallic or transition layer was observed. The wavy interface formation, as well as the distributions of temperature, pressure and plastic strain at the interface were studied through numerical simulation with Smoothed Particle Hydrodynamics (SPH). The welding mechanism of W/Cu was analyzed according to the numerical results and experimental observation, which was in accordance with the indentation mechanism proposed by Bahrani. PMID:28832527

Effect of growth temperature and precursor concentration on synthesis of CVD-graphene from camphor

NASA Astrophysics Data System (ADS)

Rajaram, Narasimman; Patel, Biren; Ray, Abhijit; Mukhopadhyay, Indrajit

2018-05-01

Here, we have synthesized CVD-graphene from camphor by using atmospheric pressure (AP)-CVD system on Cu foil. We have studied the effect of growth temperature and camphor concentration by using scanning electron microscopy (SEM) and Raman spectroscopy. The domain size of the graphene is increasing with an increase in the temperature and camphor quantity. The complete coverage of graphene on the Cu foil achieved at 1020 °C. Higher camphor quantity leads to growth of multilayer graphene. The graphene is transferred by PMMA-assisted method onto the glass substrate. The sheet resistance and transmittance of the graphene are 1.5 kohm/sq and 92.7%, respectively.

Integral window/photon beam position monitor and beam flux detectors for x-ray beams

DOEpatents

Shu, Deming; Kuzay, Tuncer M.

1995-01-01

A monitor/detector assembly in a synchrotron for either monitoring the position of a photon beam or detecting beam flux may additionally function as a vacuum barrier between the front end and downstream segment of the beamline in the synchrotron. A base flange of the monitor/detector assembly is formed of oxygen free copper with a central opening covered by a window foil that is fused thereon. The window foil is made of man-made materials, such as chemical vapor deposition diamond or cubic boron nitrate and in certain configurations includes a central opening through which the beams are transmitted. Sensors of low atomic number materials, such as aluminum or beryllium, are laid on the window foil. The configuration of the sensors on the window foil may be varied depending on the function to be performed. A contact plate of insulating material, such as aluminum oxide, is secured to the base flange and is thereby clamped against the sensor on the window foil. The sensor is coupled to external electronic signal processing devices via a gold or silver lead printed onto the contact plate and a copper post screw or alternatively via a copper screw and a copper spring that can be inserted through the contact plate and coupled to the sensors. In an alternate embodiment of the monitor/detector assembly, the sensors are sandwiched between the window foil of chemical vapor deposition diamond or cubic boron nitrate and a front foil made of similar material.

Focused Ion Beam Recovery of Hypervelocity Impact Residue in Experimental Craters on Metallic Foils

NASA Technical Reports Server (NTRS)

Graham, G. A.; Teslich, N.; Dai, Z. R.; Bradley, J. P.; Kearsley, A. T.; Horz, F.

2006-01-01

The Stardust sample return capsule will return to Earth in January 2006 with primitive debris collected from Comet 81P/Wild-2 during the fly-by encounter in 2004. In addition to the cometary particles embedded in low-density silica aerogel, there will be microcraters preserved in the Al foils (1100 series; 100 micrometers thick) that are wrapped around the sample tray assembly. Soda lime spheres (approximately 49 m in diameter) have been accelerated with a light-gas-gun into flight-grade Al foils at 6.35 km s(sup -1) to simulate the potential capture of cometary debris. The preserved crater penetrations have been analyzed using scanning electron microscopy (SEM) and x-ray energy dispersive spectroscopy (EDX) to locate and characterize remnants of the projectile material remaining within the craters. In addition, ion beam induced secondary electron imaging has proven particularly useful in identifying areas within the craters that contain residue material. Finally, high-precision focused ion beam (FIB) milling has been used to isolate and then extract an individual melt residue droplet from the interior wall of an impact penetration. This enabled further detailed elemental characterization, free from the background contamination of the Al foil substrate. The ability to recover pure melt residues using FIB will significantly extend the interpretations of the residue chemistry preserved in the Al foils returned by Stardust.

Deep learning and shapes similarity for joint segmentation and tracing single neurons in SEM images

NASA Astrophysics Data System (ADS)

Rao, Qiang; Xiao, Chi; Han, Hua; Chen, Xi; Shen, Lijun; Xie, Qiwei

2017-02-01

Extracting the structure of single neurons is critical for understanding how they function within the neural circuits. Recent developments in microscopy techniques, and the widely recognized need for openness and standardization provide a community resource for automated reconstruction of dendritic and axonal morphology of single neurons. In order to look into the fine structure of neurons, we use the Automated Tape-collecting Ultra Microtome Scanning Electron Microscopy (ATUM-SEM) to get images sequence of serial sections of animal brain tissue that densely packed with neurons. Different from other neuron reconstruction method, we propose a method that enhances the SEM images by detecting the neuronal membranes with deep convolutional neural network (DCNN) and segments single neurons by active contour with group shape similarity. We joint the segmentation and tracing together and they interact with each other by alternate iteration that tracing aids the selection of candidate region patch for active contour segmentation while the segmentation provides the neuron geometrical features which improve the robustness of tracing. The tracing model mainly relies on the neuron geometrical features and is updated after neuron being segmented on the every next section. Our method enables the reconstruction of neurons of the drosophila mushroom body which is cut to serial sections and imaged under SEM. Our method provides an elementary step for the whole reconstruction of neuronal networks.

Transmission Kikuchi diffraction and transmission electron forescatter imaging of electropolished and FIB manufactured TEM specimens

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zieliński, W., E-mail: wiziel@inmat.pw.edu.pl; Płociński, T.; Kurzydłowski, K.J.

2015-06-15

We present a study of the efficiency of the utility of scanning electron microscope (SEM)-based transmission methods for characterizing grain structure in thinned bulk metals. Foils of type 316 stainless steel were prepared by two methods commonly used for transmission electron microscopy — double-jet electropolishing and focused ion beam milling. A customized holder allowed positioning of the foils in a configuration appropriate for both transmission electron forward scatter diffraction, and for transmission imaging by the use of a forescatter detector with two diodes. We found that both crystallographic orientation maps and dark-field transmitted images could be obtained for specimens preparedmore » by either method. However, for both methods, preparation-induced artifacts may affect the quality or accuracy of transmission SEM data, especially those acquired by the use of transmission Kikuchi diffraction. Generally, the quality of orientation data was better for specimens prepared by electropolishing, due to the absence of ion-induced damage. - Highlights: • The transmission imaging and diffraction techniques are emerging in scanning electron microscopy (SEM) as promising new field of materials characterization. • The manuscript titled: “Transmission Kikuchi Diffraction and Transmission Electron Forescatter Imaging of Electropolished and FIB Manufactured TEM Specimens” documents how different specimen thinning procedures can effect efficiency of transmission Kikuchi diffraction and transmission electron forescatter imaging. • The abilities to make precision crystallographic orientation maps and dark-field images in transmission was studied on electropolished versus focus ion beam manufactured TEM specimens. • Depending on the need, electropolished and focused ion beam technique may produce suitable specimens for transmission imaging and diffraction in SEM.« less

Waste Minimization in Circuit Board Manufacturing by PARMOD(TM) Technology

DTIC Science & Technology

1998-06-24

a foil package in air or in a plastic syringe. Thermogravimetric Analysis (TGA) Ink samples were evaluated using thermogravimetric analysis in...DTA Differential Thermal Analysis FEP Fluorinated Ethylene Propylene (Teflon®) FTIR Fourier Transform Infrared spectroscopy MOD Metallo-Organic...Decomposition ROM Reactive Organic Medium SEM Scanning Electron Microscopy TGA Thermal Gravimetry Analysis Torr Unit of pressure (one mm mercury

Wideband characterization of printed circuit board materials up to 50 ghz

NASA Astrophysics Data System (ADS)

Rakov, Aleksei

A traveling-wave technique developed a few years ago in the Missouri S&T EMC Laboratory has been employed until now for characterization of PCB materials over a broad frequency range up to 30 GHz. This technique includes measuring S-parameters of the specially designed PCB test vehicles. An extension of the frequency range of printed circuit board laminate dielectric and copper foil characterization is an important problem. In this work, a new PCB test vehicle design for operating up to 50 GHz has been proposed. As the frequency range of measurements increases, the analysis of errors and uncertainties in measuring dielectric properties becomes increasingly important. Formulas for quantification of two major groups of errors, repeatability (manufacturing variability) and reproducibility (systematic) errors, in extracting dielectric constant (DK) and dissipation factor (DK) have been derived, and computations for a number of cases are presented. Conductor (copper foil) surface roughness of PCB interconnects is an important factor, which affects accuracy of DK and DF measurements. This work describes a new algorithm for semi-automatic characterization of copper foil profiles on optical or scanning electron microscopy (SEM) pictures of signal traces. The collected statistics of numerous copper foil roughness profiles allows for introducing a new metric for roughness characterization of PCB interconnects. This is an important step to refining the measured DK and DF parameters from roughness contributions. The collected foil profile data and its analysis allow for developing "design curves", which could be used by SI engineers and electronics developers in their designs.

A Microfabricated Segmented-Involute-Foil Regenerator for Enhancing Reliability and Performance of Stirling Engines. Phase III Final Report for the Radioisotope Power Conversion Technology NRA

NASA Technical Reports Server (NTRS)

Ibrahim, Mounir B.; Gedeon, David; Wood, Gary; McLean, Jeffrey

2009-01-01

Under Phase III of NASA Research Announcement contract NAS3-03124, a prototype nickel segmented-involute-foil regenerator was microfabricated and tested in a Sunpower Frequency-Test-Bed (FTB) Stirling convertor. The team for this effort consisted of Cleveland State University, Gedeon Associates, Sunpower Inc. and International Mezzo Technologies. Testing in the FTB convertor produced about the same efficiency as testing with the original random-fiber regenerator. But the high thermal conductivity of the prototype nickel regenerator was responsible for a significant performance degradation. An efficiency improvement (by a 1.04 factor, according to computer predictions) could have been achieved if the regenerator was made from a low-conductivity material. Also, the FTB convertor was not reoptimized to take full advantage of the microfabricated regenerator s low flow resistance; thus, the efficiency would likely have been even higher had the FTB been completely reoptimized. This report discusses the regenerator microfabrication process, testing of the regenerator in the Stirling FTB convertor, and the supporting analysis. Results of the pre-test computational fluid dynamics (CFD) modeling of the effects of the regenerator-test-configuration diffusers (located at each end of the regenerator) are included. The report also includes recommendations for further development of involute-foil regenerators from a higher-temperature material than nickel.

The SRS (Segmented Rail Surface) railgun: A new approach to restrike control. [Segmented rail surface

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parker J.V.

1988-01-01

A Segmented Rail Surface (SRS) structure is described that eliminates restrike arcs by progressively disconnecting segments of the rail surface after the plasma armature has passed. This technique has been demonstrated using the Los Alamos MIDI-2 railgun. Restrike was eliminated in a plasma armature acceleration experiment using metal-foil fuses as opening switches. A plasma velocity increase from 11 to 16 km/s was demonstrated using the SRS technique to eliminate the viscous drag losses associated with the restrike plasma. This technique appears to be a practical option for a laboratory launcher at present and for future multi-shot launchers if appropriate switchesmore » can be developed. 5 refs., 8 figs.« less

Prototyping Energy Storage Components for Hybrid Power Source

DTIC Science & Technology

2009-12-11

from suitable nanoporous ceramic ( anodized aluminum oxide – AAO ) and polymer (polycarbonate - PC, polyethylene terephtalate - PET) membranes . Metal...of NUC technology: a) sketch of structure, b) SEM image of membrane . The alumina membranes can be easily and inexpensively fabricated via anodization ...of aluminum foil. The pores are formed by self-assembly via pitting and reprecipation of metal oxide . Motivation The work is motivated by the

Production of multi-, oligo- and single-pore membranes using a continuous ion beam

NASA Astrophysics Data System (ADS)

Apel, P. Yu.; Ivanov, O. M.; Lizunov, N. E.; Mamonova, T. I.; Nechaev, A. N.; Olejniczak, K.; Vacik, J.; Dmitriev, S. N.

2015-12-01

Ion track membranes (ITM) have attracted significant interest over the past two decades due to their numerous applications in physical, biological, chemical, biochemical and medical experimental works. A particular feature of ITM technology is the possibility to fabricate samples with a predetermined number of pores, including single-pore membranes. The present report describes a procedure that allowed for the production of multi-, oligo- and single-pore membranes using a continuous ion beam from an IC-100 cyclotron. The beam was scanned over a set of small diaphragms, from 17 to ∼1000 μm in diameter. Ions passed through the apertures and impinged two sandwiched polymer foils, with the total thickness close to the ion range in the polymer. The foils were pulled across the ion beam at a constant speed. The ratio between the transport speed and the scanning frequency determined the distance between irradiation spots. The beam intensity and the aperture diameters were adjusted such that either several, one or no ions passed through the diaphragms during one half-period of scanning. After irradiation, the lower foil was separated from the upper foil and was etched to obtain pores 6-8 μm in diameter. The pores were found using a color chemical reaction between two reagents placed on opposite sides of the foil. The located pores were further confirmed using SEM and optical microscopy. The numbers of tracks in the irradiation spots were consistent with the Poisson statistics. Samples with single or few tracks obtained in this way were employed to study fine phenomena in ion track nanopores.

In-Flight and Post-Flight Impact Data Analysis from DEBIE2 (Debris In-Orbit Evaluator) on Board of ISS

NASA Astrophysics Data System (ADS)

Menicucci, Alessandra; Drolshagen, Gerhard; Kuitunen, Juha; Butenko, Yuriy; Mooney, Cathal

2013-08-01

DEBIE2 (Debris-in-orbit-evaluator) was launched in February 2008 as part of the European Technology Exposure Facility (EuTEF) and installed on the exterior of Columbus on ISS. DEBIE2 is an active detector, composed by 3 sensor units able to monitor the sub-micron micro-meteoroid and debris population in space. Each DEBIE sensor consists of a thin aluminium foil coupled with 2 wire grids sensitive to the plasma generated by particles impacting on the foil where also 2 piezoelectric sensors are glued. If the particle penetrates the foil, this can be detected by a third electron plasma detector located just behind the foil. The combination of these information allows to estimate the micro-particles and debris fluxes. EuTEF and DEBIE2 were retrieved after 18 months in flight and returned to Earth with the Space Shuttle Mission STS-128. In this paper, the results of the analysis of in-flight impact data are presented as well as the comparison with the models. The DEBIE2 sensor pointing the Zenith direction, was found to have one wire of the upper grid cut in two pieces by an impact. The postflight analysis focused on this sensor and included optical and SEM/EDX scanning. The results from this inspection will be also presented in this paper.

Pulse joining cartridges

DOE Office of Scientific and Technical Information (OSTI.GOV)

Golovashchenko, Sergey Fedorovich; Bonnen, John Joseph Francis

A pulsed joining tool includes a tool body that defines a cavity that receives an inner tubular member and an outer tubular member and a pulse joining cartridge. The tubular members are nested together with the cartridge being disposed around the outer tubular member. The cartridge includes a conductor, such as a wire or foil, that extends around the outer tubular member and is insulated to separate a supply segment from a return segment. A source of stored electrical energy is discharged through the conductor to join the tubular members with an electromagnetic force pulse.

Pulse joining cartridges

DOEpatents

Golovashchenko, Sergey Fedorovich; Bonnen, John Joseph Francis

2016-08-23

A pulsed joining tool includes a tool body that defines a cavity that receives an inner tubular member and an outer tubular member and a pulse joining cartridge. The tubular members are nested together with the cartridge being disposed around the outer tubular member. The cartridge includes a conductor, such as a wire or foil, that extends around the outer tubular member and is insulated to separate a supply segment from a return segment. A source of stored electrical energy is discharged through the conductor to join the tubular members with an electromagnetic force pulse.

Note: Arc discharge plasma source with plane segmented LaB{sub 6} cathode

DOE Office of Scientific and Technical Information (OSTI.GOV)

Akhmetov, T. D., E-mail: t.d.akhmetov@inp.nsk.su; Davydenko, V. I.; Ivanov, A. A.

2016-05-15

A plane cathode composed of close-packed hexagonal LaB{sub 6} (lanthanum hexaboride) segments is described. The 6 cm diameter circular cathode is heated by radiation from a graphite foil flat spiral. The cathode along with a hollow copper anode is used for the arc discharge plasma production in a newly developed linear plasma device. A separately powered coil located around the anode is used to change the magnetic field strength and geometry in the anode region. Different discharge regimes were realized using this coil.

A Novel Desulfurizer-Catalyst Combination for Logistic Fuel Reforming

DTIC Science & Technology

2009-04-27

intelligent composite between the sorbent material and the sulfur-tolerant nanocatalyst creates a realistic combination of properties to achieve these goals...the sulfur capture propensity of these formu- Figure 1. SEM images of clinoptilolite (left) and diatomite (right) support matrix. Figure 2. Sulfur...stainless steel foils to enhance the surface area. The time dependence of sulfur capture by the clinoptilolite-based (C-series) and diatomite -based (D

Highly efficient TiO2-based microreactor for photocatalytic applications.

PubMed

Krivec, Matic; Žagar, Kristina; Suhadolnik, Luka; Čeh, Miran; Dražić, Goran

2013-09-25

A photocatalytic, TiO2-based microreactor is designed and fabricated on a metal-titanium foil. The microchannel is mechanically engraved in the substrate foil, and a double-layered TiO2 anatase film is immobilized on its inner walls with a two-step synthesis, which included anodization and a hydrothermal treatment. X-ray diffraction (XRD) and scanning electron microscopy (SEM) confirm the presence of an approximately 10-μm-thick layer of titania nanotubes and anatase nanoparticles. The SEM and transmission electron microscopy (TEM) of the cross sections show a dense interface between the titanium substrate and the TiO2 nanotubes. An additional layer of TiO2-anatase nanoparticles on the top of the film provides a large, photocatalytic surface area. The metal-titanium substrate with a functionalized serpentine channel is sealed with UV-transparent Plexiglas, and four 0.8-mW UV LEDs combined with a power controller on a small printed-circuit board are fixed over the substrate. The photocatalytic activity and the kinetic properties for the degradation of caffeine are provided, and the longer-term stability of the TiO2 film is evaluated. The results show that after 6 months of use and 3600 working cycles the microreactor still exhibits 60% of its initial efficiency.

Plasma assisted synthesis of vanadium pentoxide nanoplates

NASA Astrophysics Data System (ADS)

Singh, Megha; Sharma, Rabindar Kumar; Kumar, Prabhat; Reddy, G. B.

2015-08-01

In this work, we report the growth of α-V2O5 (orthorhombic) nanoplates on glass substrate using plasma assisted sublimation process (PASP) and Nickel as catalyst. 100 nm thick film of Ni is deposited over glass substrate by thermal evaporation process. Vanadium oxide nanoplates have been deposited treating vanadium metal foil under high vacuum conditions with oxygen plasma. Vanadium foil is kept at fixed temperature growth of nanoplates of V2O5 to take place. Samples grown have been studied using XPS, XRD and HRTEM to confirm the growth of α-phase of V2O5, which revealed pure single crystal of α- V2O5 in orthorhombic crystallographic plane. Surface morphological studies using SEM and TEM show nanostructured thin film in form of plates. Uniform, vertically aligned randomly oriented nanoplates of V2O5 have been deposited.

Microfabrication of a Segmented-Involute-Foil Regenerator, Testing in a Sunpower Stirling Convertor and Supporting Modeling and Analysis

NASA Technical Reports Server (NTRS)

Ibrahim, Mounir B.; Tew, Roy C.; Gedeon, David; Wood, Gary; McLean, Jeff

2008-01-01

Under Phase II of a NASA Research Award contract, a prototype nickel segmented-involute-foil regenerator was microfabricated via LiGA and tested in the NASA/Sunpower oscillating-flow test rig. The resulting figure-of-merit was about twice that of the approx.90% porosity random-fiber material currently used in the small 50-100 W Stirling engines recently manufactured for NASA. That work was reported at the 2007 International Energy Conversion Engineering Conference in St. Louis, was also published as a NASA report, NASA/TM-2007-2149731, and has been more completely described in a recent NASA Contractor Report, NASA/CR-2007-2150062. Under a scaled-back version of the original Phase III plan, a new nickel segmentedinvolute- foil regenerator was microfabricated and has been tested in a Sunpower Frequency-Test-Bed (FTB) Stirling convertor. Testing in the FTB convertor produced about the same efficiency as testing with the original random-fiber regenerator. But the high thermal conductivity of the prototype nickel regenerator was responsible for a significant performance degradation. An efficiency improvement (by a 1.04 factor, according to computer predictions) could have been achieved if the regenerator been made from a low-conductivity material. Also the FTB convertor was not reoptimized to take full advantage of the microfabricated regenerator's low flow resistance; thus the efficiency would likely have been even higher had the FTB been completely reoptimized. This report discusses the regenerator microfabrication process, testing of the regenerator in the Stirling FTB convertor, and the supporting analysis. Results of the pre-test computational fluid dynamics (CFD) modeling of the effects of the regenerator-test-configuration diffusers (located at each end of the regenerator) is included. The report also includes recommendations for accomplishing further development of involute-foil regenerators from a higher-temperature material than nickel.

Fabrication of high-performance supercapacitors based on transversely oriented carbon nanotubes

NASA Astrophysics Data System (ADS)

Markoulidis, F.; Lei, C.; Lekakou, C.

2013-04-01

High-performance supercapacitors with organic electrolyte 1 M TEABF4 (tetraethyl ammonium tetrafluoroborate) in PC (propylene carbonate) were fabricated and tested, based on multiwall carbon nanotubes (MWNTs) deposited by electrophoresis on three types of alternative substrates: aluminium foil, ITO (indium tin oxide) coated PET (polyethylene terephthalate) film and PET film. In all cases, SEM (scanning electron microscopy) and STEM (scanning transmission electron microscopy) micrographs demonstrated that protruding, transversely oriented MWNT structures were formed, which should increase the transverse conductivity of these MWNT electrodes. The best supercapacitor cell of MWNT electrodes deposited on aluminium foil displayed good transverse orientation of the MWNT structures as well as an in-plane MWNT network at the feet of the protruding structures, which ensured good in-plane conductivity. Capacitor cells with MWNT electrodes deposited either on ITO-coated PET film or on PET film demonstrated lower but still very good performance due to the high density of transversely oriented MWNT structures (good transverse conductivity) but some in-plane inhomogeneities. Capacitor cells with drop-printed MWNTs on aluminium foil, without any transverse orientation, had 16-30 times lower specific capacitance and 5-40 times lower power density than the capacitor cells with the electrophoretically deposited MWNT electrodes.

Slumping monitoring of glass and silicone foils for x-ray space telescopes

NASA Astrophysics Data System (ADS)

Mika, M.; Pina, L.; Landova, M.; Sveda, L.; Havlikova, R.; Semencova, V.; Hudec, R.; Inneman, A.

2011-09-01

We developed a non-contact method for in-situ monitoring of the thermal slumping of glass and silicone foils to optimize this technology for the production of high quality mirrors for large aperture x-ray space telescopes. The telescope's crucial part is a high throughput, heavily nested mirror array with the angular resolution better than 5 arcsec. Its construction requires precise and light-weight segmented optics with surface micro-roughness on the order of 0.1 nm. Promising materials are glass or silicon foils shaped by thermal forming. The desired parameters can be achieved only through optimizing the slumping process. We monitored the slumping by taking the snapshots of the shapes every five minutes at constant temperature and the final shapes we measured with the Taylor Hobson profilometer. The shapes were parabolic and the deviations from a circle had the peak-to-valley values of 20-30 μm. The observed hot plastic deformation of the foils was controlled by viscous flow. We calculated and plotted the relations between the middle part deflection, viscosity, and heat-treatment time. These relations have been utilized for the development of a numerical model enabling computer simulation. By the simulation, we verify the material's properties and generate new data for the thorough optimization of the slumping process.

Security hologram foil labels with a design facilitating authenticity testing: effects of mechanical bending of substrates with the glued on holograms

NASA Astrophysics Data System (ADS)

Aubrecht, Ivo

2015-05-01

Optimal design of security holograms or diffractive optically variable image devices (DOVIDs) that would be complex enough to deter counterfeiters from attempts of mimicking but contains features readily recognizable by laymen has been addressed by many experts. This paper tries to discuss effects of mechanical bending of a flexible substrate to visual appearance of a glued-on foil DOVID. Initially plane, the DOVID is deformed to a convex- or concave-shaped curved surface. Theoretical analyses and experimental results assume the surface to be a cylindrical segment and concern rainbow-type surface-relief holograms that are recorded piecewise in a photoresist material, coated on planar and non-planar substrates.

Alternative designs for space x-ray telescopes

NASA Astrophysics Data System (ADS)

Hudec, R.; Pína, L.; Maršíková, Veronika; Černá, Daniela; Inneman, A.; Tichý, V.

2017-11-01

The X-ray optics is a key element of space X-ray telescopes, as well as other X-ray imaging instruments. The grazing incidence X-ray lenses represent the important class of X-ray optics. Most of grazing incidence (reflective) X-ray imaging systems used in astronomy but also in other (laboratory) applications are based on the Wolter 1 (or modified) arrangement. But there are also other designs and configurations proposed, used and considered for future applications both in space and in laboratory. The Kirkpatrick-Baez (K-B) lenses as well as various types of Lobster-Eye optics and MCP/Micropore optics serve as an example. Analogously to Wolter lenses, the X-rays are mostly reflected twice in these systems to create focal images. Various future projects in X-ray astronomy and astrophysics will require large segments with multiple thin shells or foils. The large Kirkpatrick-Baez modules, as well as the large Lobster-Eye X-ray telescope modules in Schmidt arrangement may serve as examples. All related space projects will require high quality and light segmented shells (bent or flat foils) with high X-ray reflectivity and excellent mechanical stability. The Multi Foil Optics (MFO) approach represent a promising alternative for both LE and K-B X-ray optical modules. Several types of reflecting substrates may be considered for these applications, with emphasis on thin float glass sheets and, more recently, high quality silicon wafers. This confirms the importance of non-Wolter X-ray optics designs for the future. The alternative designs require novel reflective substrates which are also discussed in the paper.

Coating and functionalization of high density ion track structures by atomic layer deposition

NASA Astrophysics Data System (ADS)

Mättö, Laura; Szilágyi, Imre M.; Laitinen, Mikko; Ritala, Mikko; Leskelä, Markku; Sajavaara, Timo

2016-10-01

In this study flexible TiO2 coated porous Kapton membranes are presented having electron multiplication properties. 800 nm crossing pores were fabricated into 50 μm thick Kapton membranes using ion track technology and chemical etching. Consecutively, 50 nm TiO2 films were deposited into the pores of the Kapton membranes by atomic layer deposition using Ti(iOPr)4 and water as precursors at 250 °C. The TiO2 films and coated membranes were studied by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray reflectometry (XRR). Au metal electrode fabrication onto both sides of the coated foils was achieved by electron beam evaporation. The electron multipliers were obtained by joining two coated membranes separated by a conductive spacer. The results show that electron multiplication can be achieved using ALD-coated flexible ion track polymer foils.

Transmission Electron Microscopy of Cometary Residues from Micron-Sized Craters in the Stardust Al-Foils

NASA Technical Reports Server (NTRS)

Leroux, Hugues; Stroud, Rhonda M.; Dai, Zu Rong; Graham, Giles A.; Troadec, David; Bradley, John P.; Teslich, Nick; Borg, Janet; Kearsley, Anton T.; Horz, Friedrich

2008-01-01

We report Transmission Electron Microscopy (TEM) investigations of micro-craters that originated from hypervelocity impacts of comet 81P/Wild 2 dust particles on the aluminium foil of the Stardust collector. The craters were selected by Scanning Electron Microscopy (SEM) and then prepared by Focused Ion Beam (FIB) milling techniques in order to provide electron transparent cross-sections for TEM studies. The crater residues contain both amorphous and crystalline materials in varying proportions and compositions. The amorphous component is interpreted as resulting from shock melting during the impact and the crystalline phases as relict minerals. The latter show evidence for shock metamorphism. Based on the residue morphology and the compositional variation, the impacting particles are inferred to have been dominated by mixtures of submicron olivine, pyroxene and Fe-sulfide grains, in agreement with prior results of relatively coarse-grained mineral assemblages in the aerogel collector.

Fully convolutional networks with double-label for esophageal cancer image segmentation by self-transfer learning

NASA Astrophysics Data System (ADS)

Xue, Di-Xiu; Zhang, Rong; Zhao, Yuan-Yuan; Xu, Jian-Ming; Wang, Ya-Lei

2017-07-01

Cancer recognition is the prerequisite to determine appropriate treatment. This paper focuses on the semantic segmentation task of microvascular morphological types on narrowband images to aid clinical examination of esophageal cancer. The most challenge for semantic segmentation is incomplete-labeling. Our key insight is to build fully convolutional networks (FCNs) with double-label to make pixel-wise predictions. The roi-label indicating ROIs (region of interest) is introduced as extra constraint to guild feature learning. Trained end-to-end, the FCN model with two target jointly optimizes both segmentation of sem-label (semantic label) and segmentation of roi-label within the framework of self-transfer learning based on multi-task learning theory. The learning representation ability of shared convolutional networks for sem-label is improved with support of roi-label via achieving a better understanding of information outside the ROIs. Our best FCN model gives satisfactory segmentation result with mean IU up to 77.8% (pixel accuracy > 90%). The results show that the proposed approach is able to assist clinical diagnosis to a certain extent.

Distinction between amorphous and healed planar deformation features in shocked quartz using composite color scanning electron microscope cathodoluminescence (SEM-CL) imaging

NASA Astrophysics Data System (ADS)

Hamers, Maartje F.; Pennock, Gill M.; Herwegh, Marco; Drury, Martyn R.

2016-10-01

Planar deformation features (PDFs) in quartz are one of the most reliable and most widely used forms of evidence for hypervelocity impact. PDFs can be identified in scanning electron microscope cathodoluminescence (SEM-CL) images, but not all PDFs show the same CL behavior: there are nonluminescent and red luminescent PDFs. This study aims to explain the origin of the different CL emissions in PDFs. Focused ion beam (FIB) thin foils were prepared of specific sample locations selected in composite color SEM-CL images and were analyzed in a transmission electron microscope (TEM). The FIB preparation technique allowed a direct, often one-to-one correlation between the CL images and the defect structure observed in TEM. This correlation shows that composite color SEM-CL imaging allows distinction between amorphous PDFs on one hand and healed PDFs and basal Brazil twins on the other: nonluminescent PDFs are amorphous, while healed PDFs and basal Brazil twins are red luminescent, with a dominant emission peak at 650 nm. We suggest that the red luminescence is the result of preferential beam damage along dislocations, fluid inclusions, and twin boundaries. Furthermore, a high-pressure phase (possibly stishovite) in PDFs can be detected in color SEM-CL images by its blue luminescence.

The effect of gypsum products and separating materials on the typography of denture base materials.

PubMed

Firtell, D N; Walsh, J F; Elahi, J M

1980-09-01

The typography of polymethyl methacrylate processed against various gypsum products coated with various separating materials was studied under an SEM. Tinfoil and two commercial tin foil substitutes were used as separating material during processing, and the surfaces of the resulting acrylic resin forms were studied for topographical differences. Tinfoil and alpha 2 hemihydrates produced the smoothest surfaces. As a practical solution, a good quality tinfoil substitute and alpha 1 hemihydrate could be used when processing polymethyl methacrylate resin.

The SRS railgun

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parker, J.V.

1989-01-01

A Segmented Rail Surface (SRS) structure is described that eliminates restrike arcs by progressively disconnecting segments of the rail surface after the plasma armature has passed. This technique has been demonstrated using the Los Alamos MIDI-2 railgun. Restrike was eliminated in a plasma armature acceleration experiment using metal-foil fuses as opening switches. A plasma velocity increase from 11 to 16 km/s was demonstrated using the SRS technique to eliminate the viscous drag losses associated with the restrike plasma. This technique appears to be a practical option for a laboratory launcher at present and for future multi-shot launchers if appropriate switchesmore » can be developed.« less

Preliminary Examination of Impact Craters on Al Foil from the Stardust Interstellar Dust Collector

NASA Astrophysics Data System (ADS)

Stroud, R.; Stardust Interstellar Preliminary Examination Team; 29,000 Stardust@home Dusters

2011-12-01

The Interstellar Dust Collector from the NASA Stardust mission provides an unprecedented opportunity for direct laboratory study of particles from the contemporary interstellar dust (ISD) stream in order to obtain such information as grain composition and microstructure. The collector is comprised of two collection media: silica aerogel tiles and Al foil strips. Preliminary examination (PE) of particles captured in each medium is on-going. To-date, four grains analyzed in situ in aerogel with synchrotron X-ray techniques show track trajectories and elemental composition that indicate a probable interstellar origin. In addition, we report here the discovery of one crater on an Al foil for which the residue elemental composition and crater shape are consistent with the impact of a grain of interstellar origin, although an interplanetary origin has not been ruled out. Automated mapping by SEM is the primary tool for identifi-cation of craters on the Al foils. A complete map of each foil requires collection of several thousand images at a resolution of ~ 50 nm/px. Automated software has been developed to identify crater candidates, but so far it has not replaced manual efforts. Identified candidates are then re-imaged at ~ 15 nm/px, for confirmation as impact craters. Fifteen foils have been imaged; crater identification is complete for eight, yielding 32 craters. The average areal density of craters is 9.7 cm-2, which extrapolates to ~1500 craters on the total foil collection area. Initial elemental analysis of residues in six craters has been performed with a combination of Auger spectroscopy, conventional, off-axis energy dispersive X-ray spectroscopy (EDX), on-axis, silicon drift-detector EDX. Additional analysis by TEM of the residue composition and crater morphology was obtained on FIB cross-sections of four of the craters. All craters contained detectable levels of Si and O. One crater was found to contain Mg, Si, O, Fe, Ni, S, Ca and Cr, indicative of an interstellar or interplanetary origin. The shape of this crater is consistent with the impact of a fluffy aggregate grain at < 10 km/s, similar to three of the four ISD candidates identified in the aerogel, and slower than expected for an interplanetary dust grain. In three cases the impacting grain was determined by detection of additional Ce, Zn, Ti, K, or Na to be a fragment of the solar cell cover glass.

Electromechanical transducer for acoustic telemetry system

DOEpatents

Drumheller, D.S.

1993-06-22

An improved electromechanical transducer is provided for use in an acoustic telemetry system. The transducer of this invention comprises a stack of ferroelectric ceramic disks interleaved with a plurality of spaced electrodes which are used to electrically pole the ceramic disks. The ceramic stack is housed in a metal tubular drill collar segment. The electrodes are preferably alternatively connected to ground potential and driving potential. This alternating connection of electrodes to ground and driving potential subjects each disk to an equal electric field; and the direction of the field alternates to match the alternating direction of polarization of the ceramic disks. Preferably, a thin metal foil is sandwiched between electrodes to facilitate the electrical connection. Alternatively, a thicker metal spacer plate is selectively used in place of the metal foil in order to promote thermal cooling of the ceramic stack.

Electromechanical transducer for acoustic telemetry system

DOEpatents

Drumheller, Douglas S.

1993-01-01

An improved electromechanical transducer is provided for use in an acoustic telemetry system. The transducer of this invention comprises a stack of ferroelectric ceramic disks interleaved with a plurality of spaced electrodes which are used to electrically pole the ceramic disks. The ceramic stack is housed in a metal tubular drill collar segment. The electrodes are preferably alternatively connected to ground potential and driving potential. This alternating connection of electrodes to ground and driving potential subjects each disk to an equal electric field; and the direction of the field alternates to match the alternating direction of polarization of the ceramic disks. Preferably, a thin metal foil is sandwiched between electrodes to facilitate the electrical connection. Alternatively, a thicker metal spacer plate is selectively used in place of the metal foil in order to promote thermal cooling of the ceramic stack.

A Microfabricated Segmented-Involute-Foil Regenerator for Enhancing Reliability and Performance of Stirling Engines

NASA Technical Reports Server (NTRS)

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

2007-01-01

An actual-size microfabricated regenerator comprised of a stack of 42 disks, 19 mm diameter and 0.25 mm thick, with layers of microscopic, segmented, involute-shaped flow channels was fabricated and tested. The geometry resembles layers of uniformly-spaced segmented-parallel-plates, except the plates are curved. Each disk was made from electro-plated nickel using the LiGA process. This regenerator had feature sizes close to those required for an actual Stirling engine but the overall regenerator dimensions were sized for the NASA/Sunpower oscillating-flow regenerator test rig. Testing in the oscillating-flow test rig showed the regenerator performed extremely well, significantly better than currently used random-fiber material, producing the highest figures of merit ever recorded for any regenerator tested in that rig over its approximately 20 years of use.

Microstructural Study of Micron-Sized Craters Simulating Stardust Impacts in Aluminum 1100 Targets

NASA Technical Reports Server (NTRS)

Leroux, Hugues; Borg, Janet; Troadec, David; Djouadi, Zahia; Horz, Friedrich

2006-01-01

Various microscopic techniques were used to characterize experimental micro- craters in aluminium foils to prepare for the comprehensive analysis of the cometary and interstellar particle impacts in aluminium foils to be returned by the Stardust mission. First, SEM (Scanning Electron Microscopy) and EDS (Energy Dispersive X-ray Spectroscopy) were used to study the morphology of the impact craters and the bulk composition of the residues left by soda-lime glass impactors. A more detailed structural and compositional study of impactor remnants was then performed using TEM (Transmission Electron Microscopy), EDS, and electron diffraction methods. The TEM samples were prepared by Focused Ion Beam (FIB) methods. This technique proved to be especially valuable in studying impact crater residues and impact crater morphology. Finally, we also showed that InfraRed microscopy (IR) can be a quick and reliable tool for such investigations. The combination of all of these tools enables a complete microscopic characterization of the craters.

The oxidation of aluminum at high temperature studied by Thermogravimetric Analysis and Differential Scanning Calorimetry.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coker, Eric Nicholas

2013-10-01

The oxidation in air of high-purity Al foil was studied as a function of temperature using Thermogravimetric Analysis with Differential Scanning Calorimetry (TGA/DSC). The rate and/or extent of oxidation was found to be a non-linear function of the temperature. Between 650 and 750 ÀC very little oxidation took place; at 850 ÀC oxidation occurred after an induction period, while at 950 ÀC oxidation occurred without an induction period. At oxidation temperatures between 1050 and 1150 ÀC rapid passivation of the surface of the aluminum foil occurred, while at 1250 ÀC and above, an initial rapid mass increase was observed, followedmore » by a more gradual increase in mass. The initial rapid increase was accompanied by a significant exotherm. Cross-sections of oxidized specimens were characterized by scanning electron microscopy (SEM); the observed alumina skin thicknesses correlated qualitatively with the observed mass increases.« less

Constellation-X Spectroscopy X-Ray Telescope Segmented Optic Alignment Using Piezoelectric Actuators

DTIC Science & Technology

2005-11-18

Thesis directed by R. Ryan Vallance Assistant Professor of Engineering and Applied Science, Ph.D. Report Documentation Page Form ApprovedOMB No...R. Ryan Vallance for his guidance, support, and knowledge throughout this project. His guidance has helped focus my efforts throughout my time...134-146. [24] Forest, Craig Richard . “X-ray Telescope Foil Optics: Assembly, Metrology, and Constraint.” Master’s Thesis. Massachusetts

Investigation of the crater-like microdefects induced by laser shock processing with aluminum foil as absorbent layer

NASA Astrophysics Data System (ADS)

Ye, Y. X.; Xuan, T.; Lian, Z. C.; Feng, Y. Y.; Hua, X. J.

2015-06-01

This paper reports that 3D crater-like microdefects form on the metal surface when laser shock processing (LSP) is applied. LSP was conducted on pure copper block using the aluminum foil as the absorbent material and water as the confining layer. There existed the bonding material to attach the aluminum foil on the metal target closely. The surface morphologies and metallographs of copper surfaces were characterized with 3D profiler, the optical microscopy (OM) or the scanning electron microscopy (SEM). Temperature increases of metal surface due to LSP were evaluated theoretically. It was found that, when aluminum foil was used as the absorbent material, and if there existed air bubbles in the bonding material, the air temperatures within the bubbles rose rapidly because of the adiabatic compression. So at the locations of the air bubbles, the metal materials melted and micromelting pool formed. Then under the subsequent expanding of the air bubbles, a secondary shock wave was launched against the micromelting pool and produced the crater-like microdefects on the metal surface. The temperature increases due to shock heat and high-speed deformation were not enough to melt the metal target. The temperature increase induced by the adiabatic compression of the air bubbles may also cause the gasification of the metal target. This will also help form the crater-like microdefects. The results of this paper can help to improve the surface quality of a metal target during the application of LSP. In addition, the results provide another method to fabricate 3D crater-like dents on metal surface. This has a potential application in mechanical engineering.

Thin Shell, Segmented X-Ray Mirrors

NASA Technical Reports Server (NTRS)

Petre, Robert

2010-01-01

Thin foil mirrors were introduced as a means of achieving high throughput in an X-ray astronomical imaging system in applications for which high angular resolution were not necessary. Since their introduction, their high filling factor, modest mass, relative ease of construction, and modest cost have led to their use in numerous X-ray observatories, including the Broad Band X-ray Telescope, ASCA, and Suzaku. The introduction of key innovations, including epoxy replicated surfaces, multilayer coatings, and glass mirror substrates, has led to performance improvements, and in their becoming widely used for X-ray astronomical imaging at energies above 10 keV. The use of glass substrates has also led to substantial improvement in angular resolution, and thus their incorporation into the NASA concept for the International X-ray Observatory with a planned 3 in diameter aperture. This paper traces the development of foil mirrors from their inception in the 1970's through their current and anticipated future applications.

The reliability of a segmentation methodology for assessing intramuscular adipose tissue and other soft-tissue compartments of lower leg MRI images.

PubMed

Karampatos, Sarah; Papaioannou, Alexandra; Beattie, Karen A; Maly, Monica R; Chan, Adrian; Adachi, Jonathan D; Pritchard, Janet M

2016-04-01

Determine the reliability of a magnetic resonance (MR) image segmentation protocol for quantifying intramuscular adipose tissue (IntraMAT), subcutaneous adipose tissue, total muscle and intermuscular adipose tissue (InterMAT) of the lower leg. Ten axial lower leg MRI slices were obtained from 21 postmenopausal women using a 1 Tesla peripheral MRI system. Images were analyzed using sliceOmatic™ software. The average cross-sectional areas of the tissues were computed for the ten slices. Intra-rater and inter-rater reliability were determined and expressed as the standard error of measurement (SEM) (absolute reliability) and intraclass coefficient (ICC) (relative reliability). Intra-rater and inter-rater reliability for IntraMAT were 0.991 (95% confidence interval [CI] 0.978-0.996, p < 0.05) and 0.983 (95% CI 0.958-9.993, p < 0.05), respectively. For the other soft tissue compartments, the ICCs were all >0.90 (p < 0.05). The absolute intra-rater and inter-rater reliability (expressed as SEM) for segmenting IntraMAT were 22.19 mm(2) (95% CI 16.97-32.04) and 78.89 mm(2) (95% CI 60.36-113.92), respectively. This is a reliable segmentation protocol for quantifying IntraMAT and other soft-tissue compartments of the lower leg. A standard operating procedure manual is provided to assist users, and SEM values can be used to estimate sample size and determine confidence in repeated measurements in future research.

Reliability study of tibialis posterior and selected leg muscle EMG and multi-segment foot kinematics in rheumatoid arthritis associated pes planovalgus

PubMed Central

Barn, Ruth; Rafferty, Daniel; Turner, Deborah E.; Woodburn, James

2012-01-01

Objective To determine within- and between-day reliability characteristics of electromyographic (EMG) activity patterns of selected lower leg muscles and kinematic variables in patients with rheumatoid arthritis (RA) and pes planovalgus. Methods Five patients with RA underwent gait analysis barefoot and shod on two occasions 1 week apart. Fine-wire (tibialis posterior [TP]) and surface EMG for selected muscles and 3D kinematics using a multi-segmented foot model was undertaken barefoot and shod. Reliability of pre-determined variables including EMG activity patterns and inter-segment kinematics were analysed using coefficients of multiple correlation, intraclass correlation coefficients (ICC) and the standard error of the measurement (SEM). Results Muscle activation patterns within- and between-day ranged from fair-to-good to excellent in both conditions. Discrete temporal and amplitude variables were highly variable across all muscle groups in both conditions but particularly poor for TP and peroneus longus. SEMs ranged from 1% to 9% of stance and 4% to 27% of maximum voluntary contraction; in most cases the 95% confidence interval crossed zero. Excellent within-day reliability was found for the inter-segment kinematics in both conditions. Between-day reliability ranged from fair-to-good to excellent for kinematic variables and all ICCs were excellent; the SEM ranged from 0.60° to 1.99°. Conclusion Multi-segmented foot kinematics can be reliably measured in RA patients with pes planovalgus. Serial measurement of discrete variables for TP and other selected leg muscles via EMG is not supported from the findings in this cohort of RA patients. Caution should be exercised when EMG measurements are considered to study disease progression or intervention effects. PMID:22721819

On the importance of FIB-SEM specific segmentation algorithms for porous media

DOE Office of Scientific and Technical Information (OSTI.GOV)

Salzer, Martin, E-mail: martin.salzer@uni-ulm.de; Thiele, Simon, E-mail: simon.thiele@imtek.uni-freiburg.de; Zengerle, Roland, E-mail: zengerle@imtek.uni-freiburg.de

2014-09-15

A new algorithmic approach to segmentation of highly porous three dimensional image data gained by focused ion beam tomography is described which extends the key-principle of local threshold backpropagation described in Salzer et al. (2012). The technique of focused ion beam tomography has shown to be capable of imaging the microstructure of functional materials. In order to perform a quantitative analysis on the corresponding microstructure a segmentation task needs to be performed. However, algorithmic segmentation of images obtained with focused ion beam tomography is a challenging problem for highly porous materials if filling the pore phase, e.g. with epoxy resin,more » is difficult. The gray intensities of individual voxels are not sufficient to determine the phase represented by them and usual thresholding methods are not applicable. We thus propose a new approach to segmentation that pays respect to the specifics of the imaging process of focused ion beam tomography. As an application of our approach, the segmentation of three dimensional images for a cathode material used in polymer electrolyte membrane fuel cells is discussed. We show that our approach preserves significantly more of the original nanostructure than a thresholding approach. - Highlights: • We describe a new approach to the segmentation of FIB-SEM images of porous media. • The first and last occurrences of structures are detected by analysing the z-profiles. • The algorithm is validated by comparing it to a manual segmentation. • The new approach shows significantly less artifacts than a thresholding approach. • A structural analysis also shows improved results for the obtained microstructure.« less

Fabrication of free-standing copper foils covered with highly-ordered copper nanowire arrays

NASA Astrophysics Data System (ADS)

Zaraska, Leszek; Sulka, Grzegorz D.; Jaskuła, Marian

2012-07-01

The through-hole nanoporous anodic aluminum oxide (AAO) membranes with relatively large surface area (ca. 2 cm2) were employed for fabrication of free-standing and mechanically stable copper foils covered with close-packed and highly-ordered copper nanowire arrays. The home-made AAO membranes with different pore diameters and interpore distances were fabricated via a two-step self-organized anodization of aluminum performed in sulfuric acid, oxalic acid and phosphoric acid followed by the pore opening/widening procedure. The direct current (DC) electrodeposition of copper was performed efficiently on both sides of AAO templates. The bottom side of the AAO templates was not insulated and consequently Cu nanowire arrays on thick Cu layers were obtained. The proposed template-assisted fabrication of free-standing copper nanowire array electrodes is a promising method for synthesis of nanostructured current collectors. The composition of Cu nanowires was confirmed by energy dispersive X-Ray spectroscopy (EDS) and X-ray diffraction (XRD) analyses. The structural features of nanowires were evaluated from field emission scanning electron microscopy (FE-SEM) images and compared with the characteristic parameters of anodic alumina membranes.

L-lactic acid and sodium p-toluenesulfonate co-doped polypyrrole for high performance cathode in sodium ion battery

NASA Astrophysics Data System (ADS)

Liao, Qishu; Hou, Hongying; Liu, Xianxi; Yao, Yuan; Dai, Zhipeng; Yu, Chengyi; Li, Dongdong

2018-04-01

In this work, polypyrrole (PPy) was co-doped with L-lactic acid (LA) and sodium p-toluenesulfonate (TsONa) for high performance cathode in sodium ion battery (SIB) via facile one-step electropolymerization on Fe foil. The as-synthesized LA/TsONa co-doped PPy cathode was investigated in terms of scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), galvanostatic charge/discharge and cyclic voltammetry (CV). The results suggested that some oval-bud-like LA/TsONa co-doped PPy particles did form and tightly combine with the surface of Fe foil; furthermore, LA/TsONa co-doped PPy cathode also delivered higher electrochemical performances than TsONa mono-doped PPy cathode. For example, the initial specific discharge capacity was as high as about 124 mAh/g, and the reversible specific capacity still maintained at about 110 mAh/g even after 50 cycles, higher than those of TsONa mono-doped PPy cathode. The synergy effect of multi components of LA/TsONa co-doped PPy cathode should be responsible for high electrochemical performances.

Diminutives facilitate word segmentation in natural speech: cross-linguistic evidence.

PubMed

Kempe, Vera; Brooks, Patricia J; Gillis, Steven; Samson, Graham

2007-06-01

Final-syllable invariance is characteristic of diminutives (e.g., doggie), which are a pervasive feature of the child-directed speech registers of many languages. Invariance in word endings has been shown to facilitate word segmentation (Kempe, Brooks, & Gillis, 2005) in an incidental-learning paradigm in which synthesized Dutch pseudonouns were used. To broaden the cross-linguistic evidence for this invariance effect and to increase its ecological validity, adult English speakers (n=276) were exposed to naturally spoken Dutch or Russian pseudonouns presented in sentence contexts. A forced choice test was given to assess target recognition, with foils comprising unfamiliar syllable combinations in Experiments 1 and 2 and syllable combinations straddling word boundaries in Experiment 3. A control group (n=210) received the recognition test with no prior exposure to targets. Recognition performance improved with increasing final-syllable rhyme invariance, with larger increases for the experimental group. This confirms that word ending invariance is a valid segmentation cue in artificial, as well as naturalistic, speech and that diminutives may aid segmentation in a number of languages.

Hot slumping glass technology for the grazing incidence optics of future missions with particular reference to IXO

NASA Astrophysics Data System (ADS)

Ghigo, M.; Basso, S.; Bavdaz, M.; Conconi, P.; Citterio, O.; Civitani, M.; Friedrich, P.; Gallieni, D.; Guldimann, B.; Martelli, F.; Negri, R.; Pagano, G.; Pareschi, G.; Parodi, G.; Proserpio, L.; Salmaso, B.; Scaglione, F.; Spiga, D.; Tagliaferri, G.; Terzi, L.; Tintori, M.; Vongehr, M.; Wille, E.; Winter, A.; Zambra, A.

2010-07-01

The mirrors of the International X-ray Observatory (IXO) consist of a large number of high quality segments delivering a spatial resolution better than 5 arcsec. A study concerning the slumping of thin glass foils for the IXO mirrors is under development in Europe, funded by ESA and led by the Brera Observatory. We are investigating two approaches, the "Direct" and "Indirect" slumping technologies, being respectively based on the use of convex and concave moulds. In the first case during the thermal cycle the optical surface of the glass is in direct contact with the mould surface, while in the second case it is the rear side of the foil which touches the master. Both approaches present pros and cons and aim of this study is also to make an assessment of both processes and to perform a trade-off between the two. The thin plates are made of D263glass produced by Schott. Each plate is 0.4 mm thick, with a reflecting area of 200 mm x 200 mm; the mould are made of Fused Silica. After the thermal cycle the slumped MPs are characterized to define their optical quality and microroughness. The adopted integration process foresees the bonding of the slumped foils to a rigid backplane by means of reinforcing ribs. During the bonding process the plates are constrained to stay in close contact to the surface of the master (i.e. the same mould used for the hot slumping process) by the application of a vacuum pump suction. In this way spring-back deformations and low frequency errors still present on the foil profile after slumping can be corrected. In this paper we present the preliminary results concerning achieved during the first part of the project.

Micro-fabric damages in Boom Clay inferred from cryo-BIB-SEM experiment: recent results

NASA Astrophysics Data System (ADS)

Desbois, Guillaume; Schmatz, Joyce; Klaver, Jop; Urai, Janos L.

2017-04-01

The Boom Clay is considered as a potential host rock in Belgium for nuclear waste disposal in a deep geological formation. One of the keys to understand the long-term performance of such a host rock is the fundamental understanding of coupling between microstructural evolution, poromechanical behaviour and the state of hydration of the system. At in situ conditions, Boom Clay is a nearly water-saturated (>94%) clay-rich geomaterial. Subsequently, for measurement of mechanical and transport properties in laboratory, cores of Boom Clay are vacuum-packed in Al-coated-poly-ethylene barrier foil to be best preserved at original hydric state. Because clay microstructures are very sensitive to dehydration, the validity of investigations done on such preserved or/and dried samples is often questionable. Desbois et al. (2009, 2013, 2014) showed the possibility to image fluid-filled porosity in Boom Clay, by using the FIB-cryo-SEM (FIB: Focussed Ion Beam) and FIB-cryo-SEM (BIB: Broad Ion Beam) techniques. However, surprisingly in Desbois et al. (2014), BIB-cryo-SEM experiments on Boom Clay, shown that the majority of the pores were fluid-free, contrasting with result in Desbois et al. (2009). In Desbois et al. (2014), several reasons were discussed to explain such discrepancies. The likely ones are the sealing efficiency of the Al-barrier foil at long term and the volume expansion due to the release of in-situ stress after core extraction, contributing both to dehydration and microfabric damage. This contribution presents the newest results based on cryo-BIB-SEM. Small pieces (30 mm3) of Boom Clay were preserved in liquid nitrogen after the core extraction at the MOL/Dessel Underground Research Laboratory in Belgium. A maximum of ten minutes time span was achieved between opening the core, the sub-sample extraction and the quenching of sub-samples in liquid nitrogen. First results show that all pores visible at cryo-SEM resolution are water saturated. However, water-filled micro-cracks are also present and they are interpreted to result from the releasing of in-situ stress after the core extraction. Moreover, the comparison of the clay micro-fabrics in the same preserved and dried sample suggests collapsing of the clay aggregates' pores in dried sample. These newest results are still preliminary and they need to be analysed in more details. However, if they are confirmed they may be important input to discuss about the validity of measurement of mechanical and transport properties done in laboratory. Desbois G., Urai J.L. and Kukla P.A. (2009). Morphology of the pore space in claystones - evidence from BIB/FIB ion beam sectioning and cryo-SEM observations. E-Earth, 4 :15-22. Desbois G., J.L. Urai, F. Pérez-Willard, Z. Radi, S. van Offern, I. Burkart, P.A. Kukla, U. Wollenberg (2013). Argon broad ion beam tomography in a cryogenic scanning electron microscope: a novel tool for the investigation of representative microstructures in sedimentary rocks containing pore fluid. Journal of Microscopy, 249(3): 215-235. Desbois G., Urai J.L., Hemes S., Brassinnes S., De Craen M., Sillen X. (2014). Nanometer-scale pore fluid distribution and drying damage in preserved clay cores from Belgian clay formations inferred by BIB-cryo-SEM. Engineering Geology, 170:117-131.

Multi-scale image segmentation and numerical modeling in carbonate rocks

NASA Astrophysics Data System (ADS)

Alves, G. C.; Vanorio, T.

2016-12-01

Numerical methods based on computational simulations can be an important tool in estimating physical properties of rocks. These can complement experimental results, especially when time constraints and sample availability are a problem. However, computational models created at different scales can yield conflicting results with respect to the physical laboratory. This problem is exacerbated in carbonate rocks due to their heterogeneity at all scales. We developed a multi-scale approach performing segmentation of the rock images and numerical modeling across several scales, accounting for those heterogeneities. As a first step, we measured the porosity and the elastic properties of a group of carbonate samples with varying micrite content. Then, samples were imaged by Scanning Electron Microscope (SEM) as well as optical microscope at different magnifications. We applied three different image segmentation techniques to create numerical models from the SEM images and performed numerical simulations of the elastic wave-equation. Our results show that a multi-scale approach can efficiently account for micro-porosities in tight micrite-supported samples, yielding acoustic velocities comparable to those obtained experimentally. Nevertheless, in high-porosity samples characterized by larger grain/micrite ratio, results show that SEM scale images tend to overestimate velocities, mostly due to their inability to capture macro- and/or intragranular- porosity. This suggests that, for high-porosity carbonate samples, optical microscope images would be more suited for numerical simulations.

Production and Performance of the InFOCmicronS 20-40 keV Graded Multilayer Mirror

NASA Technical Reports Server (NTRS)

Berendse, F.; Owens, S. M.; Serlemitsos, P. J.; Tueller, J.; Chan, K.-W.; Soong, Y.; Krimm, H.; Baumgartner, W. H.; Tamura, K.; Okajima, T.;

Mirror symmetric optics design for charge-stripping section in Rare Isotope Science Project

NASA Astrophysics Data System (ADS)

Kim, Hye-Jin; Kim, Hyung-Jin; Jeon, Dong-O.; Hwang, Ji-Gwang; Kim, Eun-San

2013-12-01

The main aim of the Rare Isotope Science Project is to construct a high power heavy-ion accelerator based on the superconducting linear accelerator (SCL). The heavy ion accelerator is a key research facility that will allow ground-breaking research into numerous facets of basic science, such as nuclear physics, astrophysics, atomic physics, life science, medicine and material science. The machine will provide a beam power of 400 kW with a 238U79+ beam of 8 pμA and 200 MeV/u. One of the critical components in the SCL is the charge stripper between the two segments, SCL1 and SCL2, of the SCL. The charge stripper removes electrons from the ion beams to enhance the acceleration efficiency in the subsequent SCL2. To improve the efficiency of acceleration and power in SCL2, the optimal energy of stripped ions in a solid carbon foil stripper was estimated using the code LISE++. The thickness of the solid carbon foil was 300 μg/m2. The charge stripping efficiency of the solid carbon stripper in the present study was approximately 87%. For charge selection from the ions produced by the solid carbon stripper, a dispersive section is needed down-stream of the foil. The designed optics for the dispersive section is based on the mirror-symmetric optics to minimize the effect of high-order aberrations.

FIB-SEM tomography of human skin telocytes and their extracellular vesicles

PubMed Central

Cretoiu, Dragos; Gherghiceanu, Mihaela; Hummel, Eric; Zimmermann, Hans; Simionescu, Olga; Popescu, Laurentiu M

2015-01-01

We have shown in 2012 the existence of telocytes (TCs) in human dermis. TCs were described by transmission electron microscopy (TEM) as interstitial cells located in non-epithelial spaces (stroma) of many organs (see www.telocytes.com). TCs have very long prolongations (tens to hundreds micrometers) named Telopodes (Tps). These Tps have a special conformation with dilated portions named podoms (containing mitochondria, endoplasmic reticulum and caveolae) and very thin segments (below resolving power of light microscopy), called podomers. To show the real 3D architecture of TC network, we used the most advanced available electron microscope technology: focused ion beam scanning electron microscopy (FIB-SEM) tomography. Generally, 3D reconstruction of dermal TCs by FIB-SEM tomography revealed the existence of Tps with various conformations: (i) long, flattened irregular veils (ribbon-like segments) with knobs, corresponding to podoms, and (ii) tubular structures (podomers) with uneven calibre because of irregular dilations (knobs) – the podoms. FIB-SEM tomography also showed numerous extracellular vesicles (diameter 438.6 ± 149.1 nm, n = 30) released by a human dermal TC. Our data might be useful for understanding the role(s) of TCs in intercellular signalling and communication, as well as for comprehension of pathologies like scleroderma, multiple sclerosis, psoriasis, etc. PMID:25823591

New trends in space x-ray optics

NASA Astrophysics Data System (ADS)

Hudec, R.; Maršíková, V.; Pína, L.; Inneman, A.; Skulinová, M.

2017-11-01

The X-ray optics is a key element of various X-ray telescopes, X-ray microscopes, as well as other X-ray imaging instruments. The grazing incidence X-ray lenses represent the important class of X-ray optics. Most of grazing incidence (reflective) X-ray imaging systems used in astronomy but also in other (laboratory) applications are based on the Wolter 1 (or modified) arrangement. But there are also other designs and configurations proposed, used and considered for future applications both in space and in laboratory. The Kirkpatrick-Baez (K-B) lenses as well as various types of Lobster-Eye optics and MCP/Micropore optics serve as an example. Analogously to Wolter lenses, the X-rays are mostly reflected twice in these systems to create focal images. Various future projects in X-ray astronomy and astrophysics will require large segments with multiple thin shells or foils. The large Kirkpatrick-Baez modules, as well as the large Lobster-Eye X-ray telescope modules in Schmidt arrangement may serve as examples. All these space projects will require high quality and light segmented shells (bent or flat foils) with high X-ray reflectivity and excellent mechanical stability. The Multi Foil Optics (MFO) approach represent a promising alternative for both LE and K-B X-ray optical modules. Several types of reflecting substrates may be considered for these applications, with emphasis on thin float glass sheets and, more recently, high quality silicon wafers. This confirms the importance of non- Wolter X-ray optics designs for the future. Future large space X-ray telescopes (such as IXO) require precise and light-weight X-ray optics based on numerous thin reflecting shells. Novel approaches and advanced technologies are to be exploited and developed. In this contribution, we refer on results of tested X-ray mirror shells produced by glass thermal forming (GTF) and by shaping Si wafers. Both glass foils and Si wafers are commercially available, have excellent surface microroughness of a few 0.1 nm, and low weight (the volume density is 2.5 g cm-3 for glass and 2.3 g cm-3 for Si). Technologies are needed to be exploited; how to shape these substrates to achieve the required precise Xray optics geometries without degradations of the fine surface microroughness. Although glass and recently silicon wafers are considered to represent most promising materials for future advanced large aperture space Xray telescopes, there also exist other alternative materials worth further study such as amorphous metals and glassy carbon [1]. In order to achieve sub-arsec angular resolutions, principles of active optics have to be adopted.

SemVisM: semantic visualizer for medical image

NASA Astrophysics Data System (ADS)

Landaeta, Luis; La Cruz, Alexandra; Baranya, Alexander; Vidal, María.-Esther

2015-01-01

SemVisM is a toolbox that combines medical informatics and computer graphics tools for reducing the semantic gap between low-level features and high-level semantic concepts/terms in the images. This paper presents a novel strategy for visualizing medical data annotated semantically, combining rendering techniques, and segmentation algorithms. SemVisM comprises two main components: i) AMORE (A Modest vOlume REgister) to handle input data (RAW, DAT or DICOM) and to initially annotate the images using terms defined on medical ontologies (e.g., MesH, FMA or RadLex), and ii) VOLPROB (VOlume PRObability Builder) for generating the annotated volumetric data containing the classified voxels that belong to a particular tissue. SemVisM is built on top of the semantic visualizer ANISE.1

Applications of Real Space Crystallography in Characterization of Dislocations in Geological Materials in a Scanning Electron Microscope (SEM)

NASA Astrophysics Data System (ADS)

Kaboli, S.; Burnley, P. C.

2017-12-01

Imaging and characterization of defects in crystalline materials is of significant importance in various disciplines including geoscience, materials science, and applied physics. Linear defects such as dislocations and planar defects such as twins and stacking faults, strongly influence many of the properties of crystalline materials and also reflect the conditions and degree of deformation. Dislocations have been conventionally imaged in thin foils in a transmission electron microscope (TEM). Since the development of field emission scanning electron microscopes (FE-SEM) with high gun brightness and small spot size, extensive efforts have been dedicated to the imaging and characterization of dislocations in semi-conductors using electron channeling contrast imaging (ECCI) in the SEM. The obvious advantages of using SEM over TEM include easier and non-destructive sample preparation and a large field of view enabling statistical examination of the density and distribution of dislocations and other defects. In this contribution, we extend this technique to geological materials and introduce the Real Space Crystallography methodology for imaging and complete characterization of dislocations based on bend contour contrast obtained by ECCI in FE-SEM. Bend contours map out the distortion in the crystal lattice across a deformed grain. The contrast of dislocations is maximum in the vicinity of bend contours where crystal planes diffract at small and positive deviations from the Bragg positions (as defined by Bragg's law of electron diffraction). Imaging is performed in a commercial FE-SEM equipped with a standard silicon photodiode backscattered (BSE) detector and an electron backscatter diffraction (EBSD) system for crystal orientation measurements. We demonstrate the practice of this technique in characterization of a number of geological materials in particular quartz, forsterite olivine and corundum, experimentally deformed at high pressure-temperature conditions. This new approach in microstructure characterization of deformed geologic materials in FE-SEM, without the use of etching or decoration techniques, has valuable applications to both experimentally deformed and naturally deformed specimens.

Electrochemical CO 2 Reduction on Oxide-Derived Cu Surface with Various Oxide Thicknesses

DOE PAGES

Liang, Zhixiu; Fu, Jie; Vukmirovic, Miomir B.; ...

2018-03-26

Here, cuprous oxide on copper foil electrodes prepared via electrochemical deposition and thermal annealing are investigated towards CO 2 electrochemical reduction at low overpotential. The thickness of the electrochemical deposited Cu 2O was controlled by varying the constant-current deposition time. The surface morphology and roughness were examined with SEM and CV respectively. The electrode fabricated by cuprous oxide deposited for 20 min demonstrated the best faradic efficiency (7.02%) and specific activity (0.123 mA/cm 2) towards format/formic acid formation at -0.5 V vs. RHE in CO 2 saturated 0.5 M K 2CO 3 among studied samples.

Erosion of mylar and protection by thin metal films

NASA Technical Reports Server (NTRS)

Fraundorf, P.; Lindstrom, D.; Sandford, S.; Swan, P.; Walker, R.; Zinner, E.; Pailer, N.

1983-01-01

Mylar strips, 2.5 microns thick, uncoated and coated with 50A, 100A and 200A of Al, Pd, and Au/Pd were exposed on STS-5 in order to measure the erosion of mylar and to test means of protecting thin plastic foils commonly used for space experiments in low earth orbit. Analysis by optical microscopy, SEM and STEM investigation, EDX measurements, FTIR spectroscopy and weight loss measurements showed that while up to 75 percent of the uncoated mylar was eroded during exposure, thin coatings of the above metals can protect mylar for integrated oxygen-fluxes of at least 10 to the 21st atoms/sq cm.

Electrochemical CO 2 Reduction on Oxide-Derived Cu Surface with Various Oxide Thicknesses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liang, Zhixiu; Fu, Jie; Vukmirovic, Miomir B.

Here, cuprous oxide on copper foil electrodes prepared via electrochemical deposition and thermal annealing are investigated towards CO 2 electrochemical reduction at low overpotential. The thickness of the electrochemical deposited Cu 2O was controlled by varying the constant-current deposition time. The surface morphology and roughness were examined with SEM and CV respectively. The electrode fabricated by cuprous oxide deposited for 20 min demonstrated the best faradic efficiency (7.02%) and specific activity (0.123 mA/cm 2) towards format/formic acid formation at -0.5 V vs. RHE in CO 2 saturated 0.5 M K 2CO 3 among studied samples.

Programmatically Optimized SEM Image Acquisition for Measurement of Contamination on Molybdenum Coated Foils from the NASA Genesis Mission

NASA Astrophysics Data System (ADS)

Gil, A.

2016-12-01

The NASA Genesis Mission flew high-purity collector materials on a satellite from 2001-2004 to collect a sample of the solar wind. Upon return to Earth, a spacecraft malfunction caused the onboard sample materials to be severely contaminated during the crash landing in the Utah desert. As part of an ongoing effort to decontaminate the collector materials, they are being scanned with a scanning electron microscope (SEM) to determine the amount of dirt and spacecraft debris contaminating the collectors. This effort is underway currently, but we have identified an opportunity to improve the quality of the SEM data collected. At present, many small images are acquired and stitched together to form larger images of Genesis collector pieces, which are then analyzed. The collectors are physically distorted, however, and the imaging method presently used doesn't allow imaging parameters to be adjusted between images to correct for this distortion. In order to improve the quality of the collected imaging, we are developing a program to acquire a focus map of each sample prior to image collection. The program then uses this data to adjust the position of the sample in the SEM to image all sections in focus and at a constant focal length. This is accomplished using the Python programming language, and the programmatic interface built into our Tescan VEGA Scanning Electron Microscope. Our approach, progress to date, and challenges are discussed.

Vapor-phase polymerization of poly(3,4-ethylenedioxythiophene) (PEDOT) on commercial carbon coated aluminum foil as enhanced electrodes for supercapacitors

NASA Astrophysics Data System (ADS)

Tong, Linyue; Skorenko, Kenneth H.; Faucett, Austin C.; Boyer, Steven M.; Liu, Jian; Mativetsky, Jeffrey M.; Bernier, William E.; Jones, Wayne E.

2015-11-01

Laminar composite electrodes are prepared for application in supercapacitors using a catalyzed vapor-phase polymerization (VPP) of 3,4-ethylenedioxythiophene (EDOT) on the surface of commercial carbon coated aluminum foil. These highly electrically conducting polymer films provide for rapid and stable power storage per gram at room temperature. The chemical composition, surface morphology and electrical properties are characterized by Raman spectroscopy, scanning electron microscopy (SEM), and conducting atomic force microscopy (C-AFM). A series of electrical measurements including cyclic voltammetry (CV), charge-discharge (CD) and electrochemical impedance spectroscopy are also used to evaluate electrical performance. The processing temperature of VPP shows a significant effect on PEDOT morphology, the degree of orientation and its electrical properties. The relatively high temperature leads to high specific area and large conductive domains of PEDOT layer which benefits the capacitive behavior greatly according to the data presented. Since the substrate is already highly conductive, the PEDOT based composite can be used as electrode materials directly without adding current collector. By this simple and efficient process, PEDOT based composites exhibit specific capacitance up to 134 F g-1 with the polymerization temperature of 110 °C.

Continuous-wave laser-induced glass fiber generation

NASA Astrophysics Data System (ADS)

Nishioka, Nobuyasu; Hidai, Hirofumi; Matsusaka, Souta; Chiba, Akira; Morita, Noboru

2017-09-01

Pulsed-laser-induced glass fiber generation has been reported. We demonstrate a novel glass fiber generation technique by continuous-wave laser illumination and reveal the generation mechanism. In this technique, borosilicate glass, metal foil, and a heat insulator are stacked and clamped by a jig as the sample. Glass fibers are ejected from the side surface of the borosilicate glass by laser illumination of the sample from the borosilicate glass side. SEM observation shows that nanoparticles are attached on the glass fibers. High-speed imaging reveals that small bubbles are formed at the side surface of the borosilicate glass and the bursting of the bubble ejects the fibers. The temperature at the fiber ejection point is estimated to be 1220 K. The mechanism of the fiber ejection includes the following steps: the metal thin foil heated by the laser increases the temperature of the surrounding glass by heat conduction. Since the absorption coefficient of the glass is increased by increasing the temperature, the glass starts to absorb the laser irradiation. The heated glass softens and bubbles form. When the bubble bursts, molten glass and gas inside the bubble scatter into the air to generate the glass fibers.

A SEM-correlation of the anatomy of the vitreous body: making visible the invisible.

PubMed

Jongebloed, W L; Humalda, D; Worst, J F

1986-12-30

The naked human vitreous (sclera, iris and cornea removed) suspended in water does not reveal inner structures. After ink injection into the vitreous, the presence of different compartments and the existence of cisterns becomes evident. A concept of the internal system of cisterns is given on the basis of stereoscopic-lightmicroscopic images. An attempt is made to correlate images of the complete vitreous body, obtained with a stereo-lightmicroscope, with images of segments of cisternal walls produced with a scanning electron-microscope (SEM). A comparison is made between SEM-images of the vitreous bodies of human and rabbit eyes.

FIB-SEM tomography of human skin telocytes and their extracellular vesicles.

PubMed

Cretoiu, Dragos; Gherghiceanu, Mihaela; Hummel, Eric; Zimmermann, Hans; Simionescu, Olga; Popescu, Laurentiu M

2015-04-01

We have shown in 2012 the existence of telocytes (TCs) in human dermis. TCs were described by transmission electron microscopy (TEM) as interstitial cells located in non-epithelial spaces (stroma) of many organs (see www.telocytes.com). TCs have very long prolongations (tens to hundreds micrometers) named Telopodes (Tps). These Tps have a special conformation with dilated portions named podoms (containing mitochondria, endoplasmic reticulum and caveolae) and very thin segments (below resolving power of light microscopy), called podomers. To show the real 3D architecture of TC network, we used the most advanced available electron microscope technology: focused ion beam scanning electron microscopy (FIB-SEM) tomography. Generally, 3D reconstruction of dermal TCs by FIB-SEM tomography revealed the existence of Tps with various conformations: (i) long, flattened irregular veils (ribbon-like segments) with knobs, corresponding to podoms, and (ii) tubular structures (podomers) with uneven calibre because of irregular dilations (knobs) - the podoms. FIB-SEM tomography also showed numerous extracellular vesicles (diameter 438.6 ± 149.1 nm, n = 30) released by a human dermal TC. Our data might be useful for understanding the role(s) of TCs in intercellular signalling and communication, as well as for comprehension of pathologies like scleroderma, multiple sclerosis, psoriasis, etc. © 2015 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

A Wirelessly-Powered Homecage With Segmented Copper Foils and Closed-Loop Power Control.

PubMed

Mirbozorgi, S Abdollah; Jia, Yaoyao; Canales, Daniel; Ghovanloo, Maysam

2016-10-01

A new wireless electrophysiology data acquisition system, built around a standard homecage, is presented in this paper, which can power up and communicate with sensors and actuators/stimulators attached to or implanted in small freely behaving animal subjects, such as rodents. Key abilities of the energized homecage (EnerCage) system is enabling longitudinal experiments with minimal operator involvement or interruption, while providing test subjects with an enriched environment closer to their natural habitat, without the burden of being tethered or carrying bulky batteries. The magnetic resonant multi-coil design used in the new EnerCage-HC2 automatically localizes the transmitted electromagnetic power from a single transmitter (Tx) coil at the bottom of the cage toward the receiver coil (Rx), carried on/in the animal body, obviating the need for tracking the animal or switching the coils. In order to increase the resonators' quality factor (Q > 166) at the desired operating frequency of 13.56 MHz, while maintaining a high self-resonance frequency [Formula: see text], they are made of wide copper foils and optimally segmented based on a set of design rules that can be adopted for experimental arenas with different shapes and dimensions. The Rx rectified voltage is regulated at a user-defined window [Formula: see text] by a Tx-Rx closed-loop power control (CLPC) mechanism that creates a volume inside the homecage with 42 mW of power delivered to the load (PDL), and a homogeneous power transfer efficiency (PTE) plane of 14% on average at ∼7 cm height, plus stability against angular mis-alignments of up to 80°.

X-ray optical units made of glass: achievements and perspectives

NASA Astrophysics Data System (ADS)

Civitani, M.; Basso, S.; Ghigo, M.; Pareschi, G.; Salmaso, B.; Spiga, D.; Tagliaferri, G.; Vecchi, G.; Burwitz, V.; Hartner, G. D.; Menz, B.

2014-07-01

Future X-ray telescopes with very large collecting area, like the proposed Athena with more than 2 m2 effective area at 1 keV, need to be realized as assemblies of a large number of X-ray optical units, named X-ray Optical Units (XOUs). The Brera Astronomical Observatory (INAF-OAB) is developing a new technology to manufacture these modular elements, compatible with an angular resolution of 5 arcsec HEW (Half-Energy-Width). This technique consists in stacking in a Wolter-I configuration several layers of thin foils of glass, previously formed by direct hot slumping. The achievable global angular resolution of the optics relies on the required surface shape accuracy of slumped foils, on the smoothness of the mirror surfaces and on the correct integration and co-alignment of the mirror segments operated trough a dedicated Integration Machine (IMA). In this paper we provide an overview of the project development, reporting on the very promising results achieved so far, including in-focus full illumination X-ray tests of the prototype (Proof of Concept, POC#2, integrated at the beginning of 2013) for which an HEW of 22.1'' has been measured at Panter/MPE. Moreover we report on the on-going activities, with a new integrated prototype (PoC#3). X-ray test in pencil beam revealed that at least a segment between two external ribs is characterized by an HEW well below 10''. Lastly, the overall process up-grade to go from 20 m to 12m focal length (to be compatible with Athena+ configuration) is presented.

Slumped glass optics with interfacing ribs for high angular resolution x-ray astronomy: a progress report

NASA Astrophysics Data System (ADS)

Civitani, M.; Basso, S.; Brizzolari, C.; Ghigo, M.; Pareschi, G.; Salmaso, B.; Spiga, D.; Vecchi, G.; Breunig, E.; Burwitz, V.; Hartner, G. D.; Menz, B.

2015-09-01

The Slumped Glass Optics technology, developed at INAF/OAB since a few years, is becoming a competitive solution for the realization of the future X-ray telescopes with a very large collecting area, as e.g. the proposed Athena, with more than 2 m2 effective area at 1 keV and with a high angular resolution (5'' HEW). The developed technique is based on modular elements, named X-ray Optical Units (XOUs), made of several layers of thin foils of glass, previously formed by direct hot slumping in cylindrical configuration, and then stacked in a Wolter-I configuration, through interfacing ribs. The achievable global angular resolution of the optics relies on the surface shape accuracy of the slumped foils, on the smoothness of the mirror surfaces and on the correct integration and co-alignment of the mirror segments achieved with a dedicated Integration Machine (IMA). In this paper we provide an update of the project development, reporting on the last results achieved. In particular, we will present the results obtained with full illumination X-ray tests for the last developed prototypes.

Complete grain boundaries from incomplete EBSD maps: the influence of segmentation on grain size determinations

NASA Astrophysics Data System (ADS)

Heilbronner, Renée; Kilian, Ruediger

2017-04-01

Grain size analyses are carried out for a number of reasons, for example, the dynamically recrystallized grain size of quartz is used to assess the flow stresses during deformation. Typically a thin section or polished surface is used. If the expected grain size is large enough (10 µm or larger), the images can be obtained on a light microscope, if the grain size is smaller, the SEM is used. The grain boundaries are traced (the process is called segmentation and can be done manually or via image processing) and the size of the cross sectional areas (segments) is determined. From the resulting size distributions, 'the grain size' or 'average grain size', usually a mean diameter or similar, is derived. When carrying out such grain size analyses, a number of aspects are critical for the reproducibility of the result: the resolution of the imaging equipment (light microscope or SEM), the type of images that are used for segmentation (cross polarized, partial or full orientation images, CIP versus EBSD), the segmentation procedure (algorithm) itself, the quality of the segmentation and the mathematical definition and calculation of 'the average grain size'. The quality of the segmentation depends very strongly on the criteria that are used for identifying grain boundaries (for example, angles of misorientation versus shape considerations), on pre- and post-processing (filtering) and on the quality of the recorded images (most notably on the indexing ratio). In this contribution, we consider experimentally deformed Black Hills quartzite with dynamically re-crystallized grain sizes in the range of 2 - 15 µm. We compare two basic methods of segmentations of EBSD maps (orientation based versus shape based) and explore how the choice of methods influences the result of the grain size analysis. We also compare different measures for grain size (mean versus mode versus RMS, and 2D versus 3D) in order to determine which of the definitions of 'average grain size yields the most stable results.

SIMS analysis of extended impact features on LDEF experiment

NASA Technical Reports Server (NTRS)

Amari, S.; Foote, J.; Jessberger, E. K.; Simon, C.; Stadermann, F. J.; Swan, P.; Walker, R.; Zinner, E.

1991-01-01

Discussed here are the first Secondary Ion Mass Spectroscopy (SIMS) analysis of projectile material deposited in extended impact features on Ge wafers from the trailing edge. Although most capture cells lost their plastic film covers, they contain extended impact features that apparently were produced by high velocity impacts when the plastic foils were still intact. Detailed optical scanning of all bare capture cells from the trailing edge revealed more than 100 impacts. Fifty-eight were selected by scanning electron microscope (SEM) inspection as prime candidates for SIMS analysis. Preliminary SIMS measurements were made on 15 impacts. More than half showed substantial enhancements of Mg, Al, Si, Ca, and Fe in the impact region, indicating micrometeorites as the projectiles.

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.

Irradiated microstructure of U-10Mo monolithic fuel plate at very high fission density

NASA Astrophysics Data System (ADS)

Gan, J.; Miller, B. D.; Keiser, D. D.; Jue, J. F.; Madden, J. W.; Robinson, A. B.; Ozaltun, H.; Moore, G.; Meyer, M. K.

2017-08-01

Monolithic U-10Mo alloy fuel plates with Al-6061 cladding are being developed for use in research and test reactors as low enrichment fuel (<20% U-235 enrichment) as a result of its high uranium loading capacity compared to that of U-7Mo dispersion fuel. These fuel plates contain a Zr diffusion barrier between the U-10Mo fuel and Al-6061 cladding that suppresses the interaction between the U-Mo fuel foil and Al alloy cladding that is known to be problematic under irradiation. Different methods have been employed to fabricate monolithic fuel plates, including hot-rolling with no cold-rolling. L1P09T is a hot-rolled fuel plate irradiated to high fission density in the RERTR-9B experiment. This paper discusses the TEM characterization results for this U-10Mo/Zr/Al6061 monolithic fuel plate (∼59% U-235 enrichment) irradiated in Advanced Test Reactor at Idaho National Laboratory with an unprecedented high local fission density of 9.8E+21 fissions/cm3. The calculated fuel foil centerline temperature at the beginning of life and the end of life is 141 and 194 °C, respectively. TEM lamellas were prepared using focus ion beam lift-out technique. The estimated U-Mo fuel swelling, based on the fuel foil thickness change from SEM, is approximately 76%. Large bubbles (>1 μm) are distributed evenly in U-Mo and interlink of these bubbles is evident. The average size of subdivided grains at this fission density appears similar to that at 5.2E+21 fissions/cm3. The measured average Mo and Zr content in the fuel matrix is ∼30 at% and ∼7 at%, respectively, in general agreement with the calculated Mo and Zr from fission density.

Irradiated microstructure of U-10Mo monolithic fuel plate at very high fission density

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gan, J.; Miller, B. D.; Keiser, D. D.

Monolithic U-10Mo alloy fuel plates with Al-6061 cladding are being developed for use in research and test reactors as low enrichment fuel (< 20% U-235 enrichment) as a result of its high uranium loading capacity compared to that of U-7Mo dispersion fuel. These fuel plates contain a Zr diffusion barrier between the U-10Mo fuel and Al-6061 cladding that suppresses the interaction between the U-Mo fuel foil and Al alloy cladding that is known to be problematic under irradiation. This paper discusses the TEM results of the U-10Mo/Zr/Al6061 monolithic fuel plate (Plate ID: L1P09T, ~ 59% U-235 enrichment) irradiated in Advancedmore » Test Reactor at Idaho National Laboratory as part of RERTR-9B irradiation campaign with an unprecedented high local fission density of 9.8E+21 fissions/cm3. The calculated fuel foil centerline temperature at the beginning of life and the end of life is 141 and 194 C, respectively. A total of 5 TEM lamellas were prepared using focus ion beam lift-out technique. The estimated U-Mo fuel swelling, based on the fuel foil thickness change from SEM, is approximately 76%. Large bubbles (> 1 µm) are distributed evenly in U-Mo and interlink of these bubbles is evident. The average size of subdivided grains at this fission density appears similar to that at 5.2E+21 fissions/cm3. The measured average Mo and Zr content in the fuel matrix is ~ 30 at% and ~ 7 at%, respectively, in general agreement with the calculated Mo and Zr from fission density.« less

Multi-scale structural analysis of gas diffusion layers

NASA Astrophysics Data System (ADS)

Göbel, Martin; Godehardt, Michael; Schladitz, Katja

2017-07-01

The macroscopic properties of materials are strongly determined by their micro structure. Here, transport properties of gas diffusion layers (GDL) for fuel cells are considered. In order to simulate flow and thermal properties, detailed micro structural information is essential. 3D images obtained by high-resolution computed tomography using synchrotron radiation and scanning electron microscopy (SEM) combined with focused ion beam (FIB) serial slicing were used. A recent method for reconstruction of porous structures from FIB-SEM images and sophisticated morphological image transformations were applied to segment the solid structural components. The essential algorithmic steps for segmenting the different components in the tomographic data-sets are described and discussed. In this paper, two types of GDL, based on a non-woven substrate layer and a paper substrate layer were considered, respectively. More than three components are separated within the synchrotron radiation computed tomography data. That is, fiber system, polytetrafluoroethylene (PTFE) binder/impregnation, micro porous layer (MPL), inclusions within the latter, and pore space are segmented. The usage of the thus derived 3D structure data in different simulation applications can be demonstrated. Simulations of macroscopic properties such as thermal conductivity, depending on the flooding state of the GDL are possible.

Human cardiac telocytes: 3D imaging by FIB-SEM tomography

PubMed Central

Cretoiu, D; Hummel, E; Zimmermann, H; Gherghiceanu, M; Popescu, L M

2014-01-01

Telocyte (TC) is a newly identified type of cell in the cardiac interstitium (www.telocytes.com). TCs are described by classical transmission electron microscopy as cells with very thin and long telopodes (Tps; cellular prolongations) having podoms (dilations) and podomers (very thin segments). TCs’ three-dimensional (3D) morphology is still unknown. Cardiac TCs seem to be particularly involved in long and short distance intercellular signalling and, therefore, their 3D architecture is important for understanding their spatial connections. Using focused ion beam scanning electron microscopy (FIB-SEM) we show, for the first time, the whole ultrastructural anatomy of cardiac TCs. 3D reconstruction of cardiac TCs by FIB-SEM tomography confirms that they have long, narrow but flattened (ribbon-like) telopodes, with humps generated by the podoms. FIB-SEM tomography also confirms the network made by TCs in the cardiac interstitium through adherens junctions. This study provides the first FIB-SEM tomography of a human cell type. PMID:25327290

A novel approach for the fabrication of a flexible glucose biosensor: The combination of vertically aligned CNTs and a conjugated polymer.

PubMed

Gokoglan, Tugba Ceren; Soylemez, Saniye; Kesik, Melis; Dogru, Itir Bakis; Turel, Onur; Yuksel, Recep; Unalan, Husnu Emrah; Toppare, Levent

2017-04-01

A novel flexible glucose biosensor using vertically aligned carbon nanotubes (VACNT) and a conjugated polymer (CP) was fabricated. A scaffold based on VACNT grown on aluminum foil (VACNT-Al foil) with poly (9,9-di-(2-ethylhexyl)-fluorenyl-2,7-diyl)-end capped with 2,5-diphenyl-1,2,4-oxadiazole (PFLO) was used as the immobilization matrix for the glucose biosensor. Glucose oxidase (GOx) was immobilized on a modified indium tin oxide (ITO) coated polyethylene terephthalate (PET) electrode surface. The biosensor response at a potential of -0.7V versus Ag wire was followed by the decrease in oxygen level as a result of enzymatic reaction. The biosensor exhibited a linear range between 0.02mM and 0.5mM glucose and kinetic parameters (K M app , I max , limit of detection (LOD) and sensitivity) were estimated as 0.193mM, 8.170μA, 7.035×10 -3 mM and 65.816μA/mMcm 2 , respectively. Scanning electron microscopy (SEM) was used for surface characterization. The constructed biosensor was applied to determine the glucose content in several beverages. Copyright © 2016 Elsevier Ltd. All rights reserved.

Amperometric glucose sensor based on the Ni(OH)2/Al(OH)4- electrode obtained from a thin Ni3Al foil

NASA Astrophysics Data System (ADS)

Jarosz, Magdalena; Socha, Robert P.; Jóźwik, Paweł; Sulka, Grzegorz D.

2017-06-01

In this report, we present a facile and relatively fast method to roughen the surface of Ni3Al-based intermetallic foil, and test it as an amperometric non-enzymatic glucose sensor. The alloy samples underwent chemical etching in a H3PO4:CH3COOH (HAc):HNO3:H2O (24:1:1:7 in volume) solution in order to achieve a high surface area with more electroactive sites. The Ni(OH)2/Al(OH)4- electrode was fabricated using potential cycling technique in a highly concentrated alkaline solution. The electrodes were tested electrochemically for oxidation of glucose. We have demonstrated that Ni(OH)2/Al(OH)4- electrodes exhibit high sensitivity towards glucose detection (796 μAmM-1cm-2) and short response time (3 s) upon successive addition of glucose. Moreover, as for a non-nanometric material, prepared electrodes show a relatively good linear correlation between current density and glucose concentration (0.025-0.45 mM) and limit of detection (47.6 μM). For more in-depth characterization of presented material, electrodes were examined using scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS).

An Experimental Study on Micro Clinching of Metal Foils with Cutting by Laser Shock Forming.

PubMed

Wang, Xiao; Li, Cong; Ma, Youjuan; Shen, Zongbao; Sun, Xianqing; Sha, Chaofei; Gao, Shuai; Li, Liyin; Liu, Huixia

2016-07-13

This paper describes a novel technique for joining similar and dissimilar metal foils, namely micro clinching with cutting by laser shock forming. A series of experiments were conducted to study the deformation behavior of single layer material, during which many important process parameters were determined. The process window of the 1060 pure aluminum foils and annealed copper foils produced by micro clinching with cutting was analyzed. Moreover, similar material combination (annealed copper foils) and dissimilar material combination (1060 pure aluminum foils and 304 stainless steel foils) were successfully achieved. The effect of laser energy on the interlock and minimum thickness of upper foils was investigated. In addition, the mechanical strength of different material combinations joined by micro clinching with cutting was measured in single lap shearing tests. According to the achieved results, this novel technique is more suitable for material combinations where the upper foil is thicker than lower foil. With the increase of laser energy, the interlock increased while the minimum thickness of upper foil decreased gradually. The shear strength of 1060 pure aluminum foils and 304 stainless steel foils combination was three times as large as that of 1060 pure aluminum foils and annealed copper foils combination.

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.

Roles of size and kinematics in drag reduction for two tandem flexible foils

NASA Astrophysics Data System (ADS)

Chao, Li-Ming; Zhang, Dong; Pan, Guang

2017-11-01

The effect of size and kinematics difference between two tandem flexible foils on drag reduction have been numerically studied. Compared with single foil, it is found that the kinematics difference between two foils would not play a significant role in reducing drag, while the size difference between two foils significantly affects the drag reduction in this two foil system. For leading foil, it always enjoys drag reduction and the highest drag reduction can be observed at bigger size difference and gap distance between two foil as 22%. For trailing foil, it suffers drag increase when the gap distance between two foils is smaller, while it enjoys drag decrease when the size difference between two foils is bigger enough. The hydrodynamic interaction between such actively undulated foils also has been uncovered and used to explain the mechanisms of drag reduction.

An Experimental Study on Micro Clinching of Metal Foils with Cutting by Laser Shock Forming

PubMed Central

Wang, Xiao; Li, Cong; Ma, Youjuan; Shen, Zongbao; Sun, Xianqing; Sha, Chaofei; Gao, Shuai; Li, Liyin; Liu, Huixia

2016-01-01

This paper describes a novel technique for joining similar and dissimilar metal foils, namely micro clinching with cutting by laser shock forming. A series of experiments were conducted to study the deformation behavior of single layer material, during which many important process parameters were determined. The process window of the 1060 pure aluminum foils and annealed copper foils produced by micro clinching with cutting was analyzed. Moreover, similar material combination (annealed copper foils) and dissimilar material combination (1060 pure aluminum foils and 304 stainless steel foils) were successfully achieved. The effect of laser energy on the interlock and minimum thickness of upper foils was investigated. In addition, the mechanical strength of different material combinations joined by micro clinching with cutting was measured in single lap shearing tests. According to the achieved results, this novel technique is more suitable for material combinations where the upper foil is thicker than lower foil. With the increase of laser energy, the interlock increased while the minimum thickness of upper foil decreased gradually. The shear strength of 1060 pure aluminum foils and 304 stainless steel foils combination was three times as large as that of 1060 pure aluminum foils and annealed copper foils combination. PMID:28773692

Preparation and comparative testing of advanced diamond-like carbon foils for tandem accelerators and time-of-flight spectrometers

NASA Astrophysics Data System (ADS)

Liechtenstein, V. Kh.; Ivkova, T. M.; Olshanski, E. D.; Baranov, A. M.; Repnow, R.; Hellborg, R.; Weller, R. A.; Wirth, H. L.

1999-12-01

The sputter preparation technique for thin diamond-like carbon (DLC) foils, advantageously used for ion-beam stripping and timing in accelerator experiments, has been optimized to improve the quality and the performance of the foils. Irradiation lifetimes of 5 μg/cm 2 DLC foils prepared by this technique have been compared with those for foils of approximately the same thickness, prepared by laser plasma ablation and for ethylene cracked foils when bombarded by 11 MeV Cu - - and Au --ion beams of ˜1 μA beam current at the Heidelberg MP-tandem. Standard carbon arc-evaporated foils were used as references. In these experiments, DLC stripper foils appeared to have a mean lifetime approximately two times longer than ethylene-cracked foils regardless of ion species, and compared favorably with foils prepared by laser ablation method. All these foils lasted at least, 10 times longer than standard carbon foils, when irradiated in the MP terminal. Approximately, the same improvement factor was confirmed with 3 μg/cm 2 DLC stripper foils irradiated with 2.3 MeV Ni-beams at the Pelletron accelerator in Lund. Unlike standard carbon foils, most of the advanced lifetime foils exhibited thinning during long irradiation, under clean vacuum. This suggests that sputtering of the foil by the heavy-ion beam might be a dominant process, responsible for the observed failure of these long-lived strippers. Along with specifically corrugated self-supporting DLC beam strippers, we succeeded in the fabrication of very smooth and ultra thin (˜0.5 μg/cm 2) DLC foils, mounted on grids and used as start foils for the ToF spectrometers applied in ion beam analysis.

TiO2 anode materials for lithium-ion batteries with different morphology and additives

NASA Astrophysics Data System (ADS)

Liu, Xiang; Ng, Yip Hang; Leung, Yu Hang; Liu, Fangzhou; Djurišic, Aleksandra B.; Xie, Mao Hai; Chan, Wai Kin

2014-03-01

Electrochemical performances of different TiO2 nanostructures, TiO2/CNT composite and TiO2 with titanium isopropoxide (TTIP) treatment anode were investigated. For different TiO2 nanostructures, we investigated vertically aligned TiO2 nanotubes on Ti foil and TiO2 nanotube-powders fabricated by rapid breakdown anodization technique. The morphology of the prepared samples was characterized by scanning probe microscopy (SEM). The electrochemical lithium storage abilities were studied by galvanostatic method. In addition, carbon nanotubes (CNT) additives and solution treatment process of TiO2 anode were investigated, and the results show that the additives and treatment could enhance the cycling performance of the TiO2 anode on lithium ion batteries.

Preparation, characterization, and application of titanium nano-tube array in dye-sensitized solar cells

PubMed Central

2012-01-01

The vertically orientated TiO2 nanotube array (TNA) decorated with TiO2 nano-particles was successfully fabricated by electrochemically anodizing titanium (Ti) foils followed by Ti-precursor post-treatment and annealing process. The TNA morphology characterized by SEM and TEM was found to be filled with TiO2 nano-particles interior and exterior of the TiO2 nano-tubes after titanium (IV) n-butoxide (TnB) treatment, whereas TiO2 nano-particles were only found inside of TiO2 nano-tubes upon titanium tetrachloride (TiCl4) treatment. The efficiency in TNA-based DSSCs was improved by both TnB and TiCl4 treatment presumably due to the increase of dye adsorption. PMID:22353282

Direct hot slumping of thin glass foils for future generation x-ray telescopes: current state of the art and future outlooks

NASA Astrophysics Data System (ADS)

Salmaso, B.; Basso, S.; Brizzolari, C.; Civitani, M.; Ghigo, M.; Pareschi, G.; Spiga, D.; Tagliaferri, G.; Vecchi, G.

2017-11-01

To significantly improve the performances of the current X-ray observatories, the next generation of X-ray telescopes has to be characterized by a large effective area (Aeff { 2 m2 at 1 keV) and angular resolution better than 5 arcsec. The large dimension implied by these requirements forces the use of a modular approach, splitting the optics into segments. Moreover, lightweight materials, such as glass, have to be selected for the segmented optics in order to maintain a manageable weight for the optics. Since 2009 we are developing a direct hot slumping technique assisted by pressure, in which the glass optical surface is in contact with the mould and a pressure is applied in order to force the glass to copy the mould shape. A cold slumping step is used then to integrate the mirror segments into the final Wolter-I configuration. We present the state of the art of our hot slumping technology, comparing the results obtained with different glass types and mould materials. We also provide an overview of the possibilities of this technology also in view of future developments.

Ultrastructural investigations for reducing endothelial cell damage of vein grafts during CABG-operation and practical consequences.

PubMed

Hickethier, T; Dämmrich, J; Silber, R E; Finster, S; Elert, O

1999-02-01

In the present study the influence of different storage solutions on endothelial integrity or damage was investigated with direct methods particularly with transmission electron microscopy (TEM), scanning electron microscopy (SEM) and immunohistochemistry. Saphenous vein segments of 10 cm in length were taken surgically from 6 male CABG-patients (aged 60-70) under standardized conditions. Each vein segment was cut into rings, which were incubated at room temperature for 45 minutes in different storage solutions, particularly in 0.9% sodium chloride solution and in buffered solution (M 199) with 5% human serum albumin respectively. Then, the vein segments were fixed in 3.5% glutaraldehyde and prepared for scanning and transmission electron microscopy to evaluate the endothelial damage. In addition, immunohistochemical staining (CD34, PECAM and Factor VIII) was performed. When using 0.9% sodium chloride solution, the SEM-examination revealed that 55% of the cell population was destroyed. In comparison to these findings only 26% of the endothelial cell population was damaged when the venous segment was stored in buffered solution with 5% albumin (p<0.01). In immunohistochemistry (CD34, PECAM, Factor VIII) these findings were supported. This study demonstrates the importance of storage solutions in regard to endothelial integrity. For best preservation of endothelium it is necessary to modify conventional storage methods. So, storage in buffered solution with albumin has shown much better endothelial cell preservation compared with physiological saline which might reduce the obliteration rate of CABG in future.

Reconstructing the microstructure of polyimide-silicalite mixed-matrix membranes and their particle connectivity using FIB-SEM tomography.

PubMed

Diblíková, P; Veselý, M; Sysel, P; Čapek, P

2018-03-01

Properties of a composite material made of a continuous matrix and particles often depend on microscopic details, such as contacts between particles. Focusing on processing raw focused-ion beam scanning electron microscope (FIB-SEM) tomography data, we reconstructed three mixed-matrix membrane samples made of 6FDA-ODA polyimide and silicalite-1 particles. In the first step of image processing, backscattered electron (BSE) and secondary electron (SE) signals were mixed in a ratio that was expected to obtain a segmented 3D image with a realistic volume fraction of silicalite-1. Second, after spatial alignment of the stacked FIB-SEM data, the 3D image was smoothed using adaptive median and anisotropic nonlinear diffusion filters. Third, the image was segmented using the power watershed method coupled with a seeding algorithm based on geodesic reconstruction from the markers. If the resulting volume fraction did not match the target value quantified by chemical analysis of the sample, the BSE and SE signals were mixed in another ratio and the procedure was repeated until the target volume fraction was achieved. Otherwise, the segmented 3D image (replica) was accepted and its microstructure was thoroughly characterized with special attention paid to connectivity of the silicalite phase. In terms of the phase connectivity, Monte Carlo simulations based on the pure-phase permeability values enabled us to calculate the effective permeability tensor, the main diagonal elements of which were compared with the experimental permeability. In line with the hypothesis proposed in our recent paper (Čapek, P. et al. (2014) Comput. Mater. Sci. 89, 142-156), the results confirmed that the existence of particle clusters was a key microstructural feature determining effective permeability. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.

Comparison of carbon and corrugated diamond stripper foils under operational conditions at the Los Alamos PSR

NASA Astrophysics Data System (ADS)

Spickermann, T.; Borden, M. J.; Macek, R. J.; Shaw, R. W.; Feigerle, C. S.; Sugai, I.

2008-06-01

To accumulate high-intensity proton pulses, the Los Alamos Proton Storage Ring (PSR) uses the charge-exchange injection method. H - ions merge with already circulating protons in a bending magnet, and then are stripped off their two electrons in a carbon stripper foil. The circulating protons continue to interact with the foil. Despite efforts to minimize the number of these foil hits, like "painting" of the vertical phase space, they cannot totally be eliminated. As a result, foil heating and probably also radiation damage limit the lifetime of these foils. In recent years, LANL has collaborated with KEK to improve the carbon foils in use at PSR, and these foils now last typically for about 2 months. Recently, an alternative in the form of corrugated diamond foils has been proposed for use at SNS. These foils have now been tested in PSR production for a year, and have already shown to be at least as enduring as the LANL/KEK carbon foils. Advantages of the diamond foil concept, as well as some noteworthy differences that we observed with respect to the LANL carbon foils, will be discussed here.

Human cardiac telocytes: 3D imaging by FIB-SEM tomography.

PubMed

Cretoiu, D; Hummel, E; Zimmermann, H; Gherghiceanu, M; Popescu, L M

2014-11-01

Telocyte (TC) is a newly identified type of cell in the cardiac interstitium (www.telocytes.com). TCs are described by classical transmission electron microscopy as cells with very thin and long telopodes (Tps; cellular prolongations) having podoms (dilations) and podomers (very thin segments). TCs' three-dimensional (3D) morphology is still unknown. Cardiac TCs seem to be particularly involved in long and short distance intercellular signalling and, therefore, their 3D architecture is important for understanding their spatial connections. Using focused ion beam scanning electron microscopy (FIB-SEM) we show, for the first time, the whole ultrastructural anatomy of cardiac TCs. 3D reconstruction of cardiac TCs by FIB-SEM tomography confirms that they have long, narrow but flattened (ribbon-like) telopodes, with humps generated by the podoms. FIB-SEM tomography also confirms the network made by TCs in the cardiac interstitium through adherens junctions. This study provides the first FIB-SEM tomography of a human cell type. © 2014 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

Carbon Stripper Foils Used in the Los Alamos PSR

NASA Astrophysics Data System (ADS)

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

1997-05-01

Carbon stripper foils produced by the modified controlled ACDC arc discharge method (mCADAD) at the Institute for Nuclear Study by Dr. Isao Sugai have been tested and used for high current 800-MeV beam production in the Proton Storage Ring (PSR) since 1993. Two approximately 110 μg/cm2 foils are sandwiched together to produce an equivalent 220 μg/cm^2 foil. The combined foil is supported by 4-5 μm diameter carbon fibers attached to an aluminum frame. These foils have survived as long as five months during PSR normal beam production of near 70 μA on target average current. Typical life-times of other foils vary from seven to fourteen days with lower on-target average current. Beam loss data also indicate that Sugai's foils have slower shrinkage rates than other 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.

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.; ...

2017-03-23

The magnetic recoil spectrometer uses a deuterated polyethylene polymer (CD 2) 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 CD 2 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,more » with no primary signal saturation.« less

Effects of stern-foil submerged elevation on the lift and drag of a hydrofoil craft

NASA Astrophysics Data System (ADS)

Suastika, K.; Apriansyah

2018-03-01

Effects of the stern-foil submerged elevation on the lift and drag of a hydrofoil craft are studied by using computational fluid dynamics (CFD) and by considering three alternative stern-foil submerged elevations. The submerged elevation of the front foil is kept constant in all the alternatives. From among the alternatives, the deepest stern-foil placement results in the highest stern-foil lift with the highest foil’s lift-to-drag ratio. However, considering the lift-to-drag ratio of the whole foil-strut-hull system, the shallowest stern-foil placement results in the highest lift-to-drag ratio. The struts and the foil’s submerged elevation significantly affects the drag of the whole foil-strut-hull system.

An improved segmentation method for defects inspection on steel roller surface

NASA Astrophysics Data System (ADS)

Xu, Jirui; Li, Xuekun; Cao, Yuzhong; Shi, Depeng; Yang, Jun; Jiang, Sheng; Rong, Yiming

2018-05-01

In the field of metal rolling, the quality of the steel roller's surface is significant for the final rolling products, e.g. metal sheets or foils. Besides the dimensional accuracy and surface roughness, the optical uniformity of the roller surface is also required for high quality rolling application. The typical optical defects of rollers after finish grinding include speckles, chatter marks, feed traces, and combination of all above. Unlike surface roughness, the optical defects can hardly be characterized by the topography or scanning electrical microscope measurement. Only the inspection by bared eyes of experienced engineers appears to be the effective manner for surface optical defects examination for large steel rollers. In this paper, an on-site machine vision system is designed to add on to the roller grinding machine to capture the surface image, and then an improved optical defects segmentation algorithm is developed based on the active contour model. Finally, experiments are carried out to verify the efficacy of the improved model.

A guide to analysis and reconstruction of serial block face scanning electron microscopy data

PubMed Central

TAGGART, M.; RIND, F.C.; WHITE, K.

2018-01-01

Summary Serial block face scanning electron microscopy (SBF‐SEM) is a relatively new technique that allows the acquisition of serially sectioned, imaged and digitally aligned ultrastructural data. There is a wealth of information that can be obtained from the resulting image stacks but this presents a new challenge for researchers – how to computationally analyse and make best use of the large datasets produced. One approach is to reconstruct structures and features of interest in 3D. However, the software programmes can appear overwhelming, time‐consuming and not intuitive for those new to image analysis. There are a limited number of published articles that provide sufficient detail on how to do this type of reconstruction. Therefore, the aim of this paper is to provide a detailed step‐by‐step protocol, accompanied by tutorial videos, for several types of analysis programmes that can be used on raw SBF‐SEM data, although there are more options available than can be covered here. To showcase the programmes, datasets of skeletal muscle from foetal and adult guinea pigs are initially used with procedures subsequently applied to guinea pig cardiac tissue and locust brain. The tissue is processed using the heavy metal protocol developed specifically for SBF‐SEM. Trimmed resin blocks are placed into a Zeiss Sigma SEM incorporating the Gatan 3View and the resulting image stacks are analysed in three different programmes, Fiji, Amira and MIB, using a range of tools available for segmentation. The results from the image analysis comparison show that the analysis tools are often more suited to a particular type of structure. For example, larger structures, such as nuclei and cells, can be segmented using interpolation, which speeds up analysis; single contrast structures, such as the nucleolus, can be segmented using the contrast‐based thresholding tools. Knowing the nature of the tissue and its specific structures (complexity, contrast, if there are distinct membranes, size) will help to determine the best method for reconstruction and thus maximize informative output from valuable tissue. PMID:29333754

A guide to analysis and reconstruction of serial block face scanning electron microscopy data.

PubMed

Cocks, E; Taggart, M; Rind, F C; White, K

2018-05-01

Serial block face scanning electron microscopy (SBF-SEM) is a relatively new technique that allows the acquisition of serially sectioned, imaged and digitally aligned ultrastructural data. There is a wealth of information that can be obtained from the resulting image stacks but this presents a new challenge for researchers - how to computationally analyse and make best use of the large datasets produced. One approach is to reconstruct structures and features of interest in 3D. However, the software programmes can appear overwhelming, time-consuming and not intuitive for those new to image analysis. There are a limited number of published articles that provide sufficient detail on how to do this type of reconstruction. Therefore, the aim of this paper is to provide a detailed step-by-step protocol, accompanied by tutorial videos, for several types of analysis programmes that can be used on raw SBF-SEM data, although there are more options available than can be covered here. To showcase the programmes, datasets of skeletal muscle from foetal and adult guinea pigs are initially used with procedures subsequently applied to guinea pig cardiac tissue and locust brain. The tissue is processed using the heavy metal protocol developed specifically for SBF-SEM. Trimmed resin blocks are placed into a Zeiss Sigma SEM incorporating the Gatan 3View and the resulting image stacks are analysed in three different programmes, Fiji, Amira and MIB, using a range of tools available for segmentation. The results from the image analysis comparison show that the analysis tools are often more suited to a particular type of structure. For example, larger structures, such as nuclei and cells, can be segmented using interpolation, which speeds up analysis; single contrast structures, such as the nucleolus, can be segmented using the contrast-based thresholding tools. Knowing the nature of the tissue and its specific structures (complexity, contrast, if there are distinct membranes, size) will help to determine the best method for reconstruction and thus maximize informative output from valuable tissue. © 2018 The Authors. Journal of Microscopy published by John Wiley & Sons Ltd on behalf of Royal Microscopical Society.

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.

Composite uranium carbide targets at TRIUMF: Development and characterization with SEM, XRD, XRF and L-edge densitometry

NASA Astrophysics Data System (ADS)

Kunz, Peter; Bricault, Pierre; Dombsky, Marik; Erdmann, Nicole; Hanemaayer, Vicky; Wong, John; Lützenkirchen, Klaus

2013-09-01

The production of radioactive ion beams (RIB) from spallation targets by irradiation with a continuous 500 MeV proton beam, has been routine at TRIUMF for several years. Based on the experience with composite refractory carbide targets a procedure for the fabrication of UC2/C targets was developed. It includes the preparation of UC2 by carbothermal reduction of UO2, the slip-casting of fine-grained UC2/C slurry on graphite foil under inert gas atmosphere and the cutting of composite target discs which are stacked up to a lamellar structure. The thermal properties of such an arrangement are adequate to withstand the high power deposition of an intense, continuous proton beam and also beneficial for the fast release of short-lived radioactive isotopes. Molecular structure, particle size and the impact of sintering of the target discs were investigated via XRD and SEM. Thickness and mass distribution were measured with position-sensitive LIII-edge densitometry. The results confirm that the properties of the UC2/C target material are well suited for RIB production at TRIUMF while there is still room for improvement with regard to uniformity of mass distribution in target disc thickness.

Multi-dimensional effects in radiation pressure acceleration of ions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tripathi, V. K., E-mail: tripathivipin@yahoo.co.in

A laser carries momentum. On reflection from an ultra-thin overdense plasma foil, it deposits recoil momentum on the foil, i.e. exerts radiation pressure on the foil electrons and pushes them to the rear. The space charge field thus created takes the ions along, accelerating the electron-ion double layer as a single unit. When the foil has surface ripple, of wavelength comparable to laser wavelength, the radiation pressure acts non-uniformly on the foil and the perturbation grows as Reyleigh-Taylor (RT) instability as the foil moves. The finite spot size of the laser causes foil to bend. These effects limit the quasi-monomore » energy acceleration of ions. Multi-ion foils, e.g., diamond like carbon foil embedded with protons offer the possibility of suppressing RT instability.« less

50th Annual Fuze Conference.Session 3 and 4

DTIC Science & Technology

2006-05-11

Exploding Foil Initiator Research • Research on Explosives • Conclusion Wim Prinse Research Scientist3 TNO has organised...Research Scientist6 Exploding Foil Initiator Research • Electrical circuit • Exploding foil • Velocity of the flyer • Driver Explosive • Secondary...90% efficiency of energy deposited in the exploding foil (50 % other circuits) Wim Prinse Research Scientist8 Exploding foil • Dimension of the foil

Method and apparatus for coating thin foil with a boron coating

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lacy, Jeffrey L.

An apparatus and a process is disclosed for applying a boron coating to a thin foil. Preferably, the process is a continuous, in-line process for applying a coating to a thin foil comprising wrapping the foil around a rotating and translating mandrel, cleaning the foil with glow discharge in an etching chamber as the mandrel with the foil moves through the chamber, sputtering the foil with boron carbide in a sputtering chamber as the mandrel moves through the sputtering chamber, and unwinding the foil off the mandrel after it has been coated. The apparatus for applying a coating to amore » thin foil comprises an elongated mandrel. Foil preferably passes from a reel to the mandrel by passing through a seal near the initial portion of an etching chamber. The mandrel has a translation drive system for moving the mandrel forward and a rotational drive system for rotating mandrel as it moves forward. The etching chamber utilizes glow discharge on a surface of the foil as the mandrel moves through said etching chamber. A sputtering chamber, downstream of the etching chamber, applies a thin layer comprising boron onto the surface of the foil as said mandrel moves through said sputtering chamber. Preferably, the coated foil passes from the mandrel to a second reel by passing through a seal near the terminal portion of the sputtering chamber.« less

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.

FAST OPENING SWITCH

DOEpatents

Bender, M.; Bennett, F.K.; Kuckes, A.F.

1963-09-17

A fast-acting electric switch is described for rapidly opening a circuit carrying large amounts of electrical power. A thin, conducting foil bridges a gap in this circuit and means are provided for producing a magnetic field and eddy currents in the foil, whereby the foil is rapidly broken to open the circuit across the gap. Advantageously the foil has a hole forming two narrow portions in the foil and the means producing the magnetic field and eddy currents comprises an annular coil having its annulus coaxial with the hole in the foil and turns adjacent the narrow portions of the foil. An electrical current flows through the coil to produce the magnetic field and eddy currents in the foil. (AEC)

Image contrast enhancement of Ni/YSZ anode during the slice-and-view process in FIB-SEM.

PubMed

Liu, Shu-Sheng; Takayama, Akiko; Matsumura, Syo; Koyama, Michihisa

2016-03-01

Focused ion beam-scanning electron microscopy (FIB-SEM) is a widely used and easily operational equipment for three-dimensional reconstruction with flexible analysis volume. It has been using successfully and increasingly in the field of solid oxide fuel cell. However, the phase contrast of the SEM images is indistinct in many cases, which will bring difficulties to the image processing. Herein, the phase contrast of a conventional Ni/yttria stabilized zirconia anode is tuned in an FIB-SEM with In-Lens secondary electron (SE) and backscattered electron detectors. Two accessories, tungsten probe and carbon nozzle, are inserted during the observation. The former has no influence on the contrast. When the carbon nozzle is inserted, best and distinct contrast can be obtained by In-Lens SE detector. This method is novel for contrast enhancement. Phase segmentation of the image can be automatically performed. The related mechanism for different images is discussed. © 2015 The Authors Journal of Microscopy © 2015 Royal Microscopical Society.

Au-C allotrope nano-composite films at extreme conditions generated by intense ultra-short laser

NASA Astrophysics Data System (ADS)

Khan, Saif A.; Saravanan, K.; Tayyab, M.; Bagchi, S.; Avasthi, D. K.

2016-07-01

Structural evolution of gold-carbon allotrope nano-composite films under relativistically intense, ultra-short laser pulse irradiation is studied in this work. Au-C nano-composite films, having 4 and 10 at.% of Au, were deposited by co-sputtering technique on silicon substrates. Au-C60 NC films with 2.5 at.% Au were deposited on 12 μm thick Al foil using co-evaporation technique. These samples were radiated with single pulse from 45 fs, 10 TW Ti:Sapphire Laser at RRCAT at an intensity of 3 × 1018 W cm-2. The morphological and compositional changes were investigated using scanning electron microscopy (SEM) and Rutherford back-scattering spectrometry (RBS) techniques. Laser pulse created three morphologically distinct zones around the point of impact on samples with silicon substrates. The gold content in 600 μm circular region around a point of impact is found to reduce by a factor of five. Annular rings of ∼70 nm in diameter were observed in case of Au-C NC film after irradiation. Laser pulse created a hole of about 400 μm in the sample with Al foil as substrate and wavy structures of 6 μm wavelength are found to be created around this hole. The study shows radial variation in nano-structure formation with varying local intensity of laser pulse.

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.

A new modal-based approach for modelling the bump foil structure in the simultaneous solution of foil-air bearing rotor dynamic problems

NASA Astrophysics Data System (ADS)

Bin Hassan, M. F.; Bonello, P.

2017-05-01

Recently-proposed techniques for the simultaneous solution of foil-air bearing (FAB) rotor dynamic problems have been limited to a simple bump foil model in which the individual bumps were modelled as independent spring-damper (ISD) subsystems. The present paper addresses this limitation by introducing a modal model of the bump foil structure into the simultaneous solution scheme. The dynamics of the corrugated bump foil structure are first studied using the finite element (FE) technique. This study is experimentally validated using a purpose-made corrugated foil structure. Based on the findings of this study, it is proposed that the dynamics of the full foil structure, including bump interaction and foil inertia, can be represented by a modal model comprising a limited number of modes. This full foil structure modal model (FFSMM) is then adapted into the rotordynamic FAB problem solution scheme, instead of the ISD model. Preliminary results using the FFSMM under static and unbalance excitation conditions are proven to be reliable by comparison against the corresponding ISD foil model results and by cross-correlating different methods for computing the deflection of the full foil structure. The rotor-bearing model is also validated against experimental and theoretical results in the literature.

Single-step simultaneous side-by-side placement of a self-expandable metallic stent with a 6-Fr delivery system for unresectable malignant hilar biliary obstruction: a feasibility study.

PubMed

Kawakubo, Kazumichi; Kawakami, Hiroshi; Kuwatani, Masaki; Kudo, Taiki; Abe, Yoko; Kawahata, Shuhei; Kubo, Kimitoshi; Kubota, Yoshimasa; Sakamoto, Naoya

2015-02-01

Bilateral self-expandable metallic stent (SEMS) placement for the management of unresectable malignant hilar biliary obstruction (UMHBO) is technically challenging to perform using the existing metallic stents with thick delivery systems. The recently developed 6-Fr delivery systems could facilitate a single-step simultaneous side-by-side placement through the accessory channel of the duodenoscope. The aim of this study was to evaluate the feasibility of this procedure. Between May and September 2013, 13 consecutive patients with UMHBO underwent a single-step simultaneous side-by-side placement of SEMS with the 6-Fr delivery system. The technical success rate, stent patency, and rate of complications were evaluated from the prospectively collected database. Technical success was achieved in 11 (84.6%, 95% confidence interval [CI]: 57.8-95.8) patients. The median procedure time was 25 min. Early and late complications were observed in 23% (one segmental cholangitis and two liver abscesses) and 15% (one segmental cholangitis and one cholecystitis) patients, respectively. Median dysfunction free patency was 263 days (95% CI: 37-263). Five patients (38%) experienced stent occlusion that was successfully managed by endoscopic stent placement. A single-step simultaneous side-by-side placement of SEMS with a 6-Fr delivery system was feasible for the management of UMHBO. © 2014 Japanese Society of Hepato-Biliary-Pancreatic Surgery.

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

... Status, Reynolds Packaging LLC (Aluminum Foil Liner Stock), Louisville, Kentucky Pursuant to its...-purpose subzone at the aluminum foil liner stock manufacturing and distribution facilities of Reynolds... manufacturing and distribution of aluminum foil liner stock and aluminum foil at the facilities of Reynolds...

50th Annual Fuze Conference Sessions 3 and 4 Held in Norfolk, Virginia on May 9-11, 2006

DTIC Science & Technology

2006-05-11

Exploding Foil Initiator Research • Research on Explosives • Conclusion Wim Prinse Research Scientist3 TNO has organised...Research Scientist6 Exploding Foil Initiator Research • Electrical circuit • Exploding foil • Velocity of the flyer • Driver Explosive • Secondary...90% efficiency of energy deposited in the exploding foil (50 % other circuits) Wim Prinse Research Scientist8 Exploding foil • Dimension of the foil

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.

Birefringence and dichroism of poly(vinyl-alcohol) foils containing phthalazinium ylids

NASA Astrophysics Data System (ADS)

Rogojanu, Alina; Dascalu, Carmen Felicia; Zelinschi, Beatrice Carmen; Caprosu, Maria; Dorohoi, Dana Ortansa

2011-10-01

Pure and colored with phthalazinium ylids poly(vinyl-alcohol) (PVA) foils were stretched under gentile heating. The birefringence of the thin foils was determined with a Babinet compensator standardized for yellow radiation of a Sodium lamp. The determined birefringence of the colored PVA foils is higher than that of the pure PVA foils. This fact indicates that the phthalazinium ylids facilitate the increase in the anisotropy of the stretched foils. The visible absorption electronic band of phthalazinium ylids was used to estimate the dichroic ratio and the degree of order of the ylid molecules in the stretched PVA foils. An increase in dichroism and birefringence with the degree of stretching has been evidenced for uncolored and colored PVA foils.

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.

Double-layer effects on the lifetime of newly developed HBC-foils for RCS of J-PARC

NASA Astrophysics Data System (ADS)

Sugai, I.; Takeda, Y.; Oyaizu, M.; Kawakami, H.; Irie, Y.; Takagi, A.; Hattori, H.; Kawasaki, K.

2010-02-01

We have developed hybrid type boron-mixed carbon (HBC) foils for the rapid cycling synchrotron (RCS) of Japan-proton accelerator research complex (J-PARC) using the controlled DC arc-discharge method. The method has been found suitable for the production of thick foils up to a maximum of 700 μg/cm 2 due to the strong adhesion to the substrate. The foils thus produced showed rather long lifetime. By the development, high-temperature damage (foil deformation, thickness reduction and pinhole formation) of the foil was significantly mitigated even at a temperature of approximately 1700 K. However, when the foil temperature was higher than about 1800 K, especially pinhole formation in the irradiated area of the foil and its peripheries were always observed. In order to relieve high-temperature damage, we investigated the possibility to lower the temperature rise in single and double layer HBC-foils while keeping the total thickness the same. We also compared the lifetime of the single and the double layer HBC-foils as well as diamond and commercially available foils, using a 3.2 MeV Ne + ion beam from the Van de Graaff accelerator.

Electron Microscopy Studies of Comet Wild-2 Particulate Residue Preserved in the Stardust Metallic Foil Craters

NASA Astrophysics Data System (ADS)

Graham, G. A.; Kearsley, A. T.; Dai, Z.; Leroux, H.; Teslich, N. E.; Stroud, R.; Borg, J.; Bradley, J. P.; Horz, F. P.; Zolensky, M.

2006-12-01

The study of comets is fundamental to the understanding of early solar system processes. Much of the current knowledge of cometary compositions comes from `fly-by' missions or remote sensing studies but not, until now, from the laboratory analyses of samples. The Stardust spacecraft (NASA's 4th Discovery mission) was launched in 1999 and in January 2004 had a successful fly-by close to the nucleus of comet Wild 2. During the encounter, the collector tray assembly containing the principle particle capture technology of low- density silica aerogel was deployed. In addition, the metallic foils (1100 series Aluminum) wrapped around the collector frame also picked up material from the 6.1 km/s cometary particle collisions. Since the retrieval of the sample return capsule in January 2006, and as part of the preliminary examination, a selected number of foils have been scanned using SEM-EDX to locate cometary dust derived impact craters. Craters ranging from 100 nanometers to several hundreds of micrometers in diameter, containing both monomineralic and polymineralic projectile melts, have been identified, measured and analyzed. Focused ion beam microscopy techniques have been used to take cross-section slices of either individual craters or specific residue fragments, and thin them to electron transparency. TEM-EDX analysis of these slices shows that crystalline grains are occasionally preserved, despite the high shock pressures and temperatures that caused most of the particle to melt. Observations from the crater residues make a useful addition to studies of the composition and mineralogy of the cometary particulates preserved within the impact tracks in the silica aerogel. This work was in part performed under the auspices of the U.S. Department of Energy, National Nuclear Security Administration by the University of California, Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48.

Quantitative analysis of nano-pore geomaterials and representative sampling for digital rock physics

NASA Astrophysics Data System (ADS)

Yoon, H.; Dewers, T. A.

2014-12-01

Geomaterials containing nano-pores (e.g., shales and carbonate rocks) have become increasingly important for emerging problems such as unconventional gas and oil resources, enhanced oil recovery, and geologic storage of CO2. Accurate prediction of coupled geophysical and chemical processes at the pore scale requires realistic representation of pore structure and topology. This is especially true for chalk materials, where pore networks are small and complex, and require characterization at sub-micron scale. In this work, we apply laser scanning confocal microscopy to characterize pore structures and microlithofacies at micron- and greater scales and dual focused ion beam-scanning electron microscopy (FIB-SEM) for 3D imaging of nanometer-to-micron scale microcracks and pore distributions. With imaging techniques advanced for nano-pore characterization, a problem of scale with FIB-SEM images is how to take nanometer scale information and apply it to the thin-section or larger scale. In this work, several texture characterization techniques including graph-based spectral segmentation, support vector machine, and principal component analysis are applied for segmentation clusters represented by 1-2 FIB-SEM samples per each cluster. Geometric and topological properties are analyzed and lattice-Boltzmann method (LBM) is used to obtain permeability at several different scales. Upscaling of permeability to the Darcy scale (e.g., the thin-section scale) with image dataset will be discussed with emphasis on understanding microfracture-matrix interaction, representative volume for FIB-SEM sampling, and multiphase flow and reactive transport. Funding from the DOE Basic Energy Sciences Geosciences Program is gratefully acknowledged. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Management of benign biliary strictures with a novel retrievable self-expandable metal stent.

PubMed

Hu, Bing; Leung, Joseph W; Gao, Dao Jian; Wang, Tian Tian; Wu, Jun

2014-03-01

Endoscopic placement of covered self-expandable metal stent (SEMS) has gained popularity in the management of benign biliary strictures (BBS). The existing SEMS has been designed primarily to palliate malignant biliary obstruction and has a high frequency of stent migration, difficulty in retrieval and stricture recurrence after stent removal. This study aimed to design a novel retrievable SEMS dedicated to the treatment of extrahepatic BBS and evaluate its clinical efficacy and safety. A short fully covered SEMS (FCSEMS) with a retrieval lasso was designed for the specific treatment of BBS. A total of 45 patients with segmental extrahepatic BBS were included in this study. The stent was placed entirely inside the bile duct with only the retrieval lasso extending from the papilla. The stents were recommended to be in situ for 6 to 12 months before removal. The FCSEMS was successfully placed in all 45 patients. In all, 33 patients had their FCSEMS successfully removed after a mean period of 8.6 ± 3.7 (range 2-15.5) months. Stent migration occurred in 9.1% of the patients. During a mean follow-up of 18.9 months after stent removal, recurrent stricture was found in 2 (6.1%) patients and was successfully treated with a second FCSEMS. Overall, the strictures resolved in 30/33 (90.9%) patients. Intraductal placement of a short FCSEMS is suitable for the treatment of segmental extrahepatic BBS. This new removable design offered prolonged stenting and drainage for BBS for up to one year with minimal complications. © 2013 Chinese Medical Association Shanghai Branch, Chinese Society of Gastroenterology, Renji Hospital Affiliated to Shanghai Jiaotong University School of Medicine and Wiley Publishing Asia Pty Ltd.

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…

Method for fabricating .sup.99 Mo production targets using low enriched uranium, .sup.99 Mo production targets comprising low enriched uranium

DOEpatents

Wiencek, Thomas C.; Matos, James E.; Hofman, Gerard L.

1997-01-01

A radioisotope production target and a method for fabricating a radioisotope production target is provided, wherein the target comprises an inner cylinder, a foil of fissionable material circumferentially contacting the outer surface of the inner cylinder, and an outer hollow cylinder adapted to receive the substantially foil-covered inner cylinder and compress tightly against the foil to provide good mechanical contact therewith. The method for fabricating a primary target for the production of fission products comprises preparing a first substrate to receive a foil of fissionable material so as to allow for later removal of the foil from the first substrate, preparing a second substrate to receive the foil so as to allow for later removal of the foil from the second substrate; attaching the first substrate to the second substrate such that the foil is sandwiched between the first substrate and second substrate to prevent foil exposure to ambient atmosphere, and compressing the exposed surfaces of the first and second substrate to assure snug mechanical contact between the foil, the first substrate and the second substrate.

Method for fabricating .sup.99 Mo production targets using low enriched uranium, .sup.99 Mo production targets comprising low enriched uranium

DOEpatents

Wiencek, Thomas C [Orland Park, IL; Matos, James E [Oak Park, IL; Hofman, Gerard L [Downers Grove, IL

2000-12-12

A radioisotope production target and a method for fabricating a radioisotope production target is provided, wherein the target comprises an inner cylinder, a foil of fissionable material circumferentially contacting the outer surface of the inner cylinder, and an outer hollow cylinder adapted to receive the substantially foil-covered inner cylinder and compress tightly against the foil to provide good mechanical contact therewith. The method for fabricating a primary target for the production of fission products comprises preparing a first substrate to receive a foil of fissionable material so as to allow for later removal of the foil from the first substrate, preparing a second substrate to receive the foil so as to allow for later removal of the foil from the second substrate; attaching the first substrate to the second substrate such that the foil is sandwiched between the first substrate and second substrate to prevent foil exposure to ambient atmosphere, and compressing the exposed surfaces of the first and second substrate to assure snug mechanical contact between the foil, the first substrate and the second substrate.

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.

Critical Configuration and Physics Measurements for Beryllium Reflected Assemblies of U(93.15)O₂ Fuel Rods (1.506-cm Pitch and 7-Tube Clusters)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marshall, Margaret A.; Bess, John D.; Briggs, J. Blair

2015-03-01

Cadmium ratios were measured with enriched uranium metal foils at various locations in the assembly with the fuel tube at the 1.506-cm spacing. They are described in the following subsections. The experiment configuration was the same as the first critical configuration described in HEU-COMP-FAST-004 (Case 1). The experimenter placed 0.75-cm-diameter × 0.010-cm-thick 93.15%-235U-enriched uranium metal foils with and without 0.051-cm-thick cadmium covers at various locations in the core and top reflector. One part of the cadmium cover was cupshape and contained the uranium foil. The other part was a lid that fit over the exposed side of the foil whenmore » it was in the cup shaped section of the cover. As can be seen in the logbook, two runs were required to obtain all the measurements necessary for the cadmium ratio. The bare foil measurements within the top reflector were run first as part of the axial foil activation measurements. The results of this run are used for both the axial activation results and the cadmium ratios. Cadmium covered foils were then placed at the same location through the top reflector in a different run. Three pairs of bare and cadmium covered foils were also placed through the core tank. One pair was placed at the axial center of a fuel tube 11.35 cm from the center of the core. Two pairs of foils were placed on top of fuel tubes 3.02 and 12.06 cm from the center of the core. The activation of the uranium metal foils was measured after removal from the assembly using two lead shielded NaI scintillation detectors as follows. The NaI scintillators were carefully matched and had detection efficiencies for counting delayed-fission-product gamma rays with energies above 250 KeV within 5%. In all foil activation measurements, one foil at a specific location was used as a normalizing foil to remove the effects of the decay of fission products during the counting measurements with the NaI detectors. The normalization foil was placed on one NaI scintillator and the other foil on the other NaI detector and the activities measured simultaneously. The activation of a particular foil was compared to that of the normalization foil by dividing the count rate for each foil by that of the normalization foil. To correct for the differing efficiencies of the two NaI detectors, the normalization foil was counted in Detector 1 simultaneously with the foil at position x in Detector 2, and then the normalization foil was counted simultaneously in Detector 2 with the foil from position x in Counter 1. The activity of the foil from position x was divided by the activity of the normalization foil counted simultaneously. This resulted in obtaining two values of the ratio that were then averaged. This procedure essentially removed the effect of the differing efficiencies of the two NaI detectors. Differing efficiencies of 10% resulted in errors in the ratios measured to less than 1%. The background counting rates obatined with the foils used for the measurements on the NaI detectors before their irradiation measurement were subtracted from all count rates. The results of the cadmium ratio measurements are given in Table 1.3-1 and Figure 1.3-1. “No correction has been made for self shielding in the foils” (Reference 3).« less

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

DOEpatents

Beuhler, Robert J [East Moriches, NY; White, Michael G [Blue Point, NY; Hrbek, Jan [Rocky Point, NY

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.

Imaging bolometer

DOEpatents

Wurden, G.A.

1999-01-19

Radiation-hard, steady-state imaging bolometer is disclosed. A bolometer employing infrared (IR) imaging of a segmented-matrix absorber of plasma radiation in a cooled-pinhole camera geometry is described. The bolometer design parameters are determined by modeling the temperature of the foils from which the absorbing matrix is fabricated by using a two-dimensional time-dependent solution of the heat conduction equation. The resulting design will give a steady-state bolometry capability, with approximately 100 Hz time resolution, while simultaneously providing hundreds of channels of spatial information. No wiring harnesses will be required, as the temperature-rise data will be measured via an IR camera. The resulting spatial data may be used to tomographically investigate the profile of plasmas. 2 figs.

Imaging bolometer

DOEpatents

Wurden, Glen A.

1999-01-01

Radiation-hard, steady-state imaging bolometer. A bolometer employing infrared (IR) imaging of a segmented-matrix absorber of plasma radiation in a cooled-pinhole camera geometry is described. The bolometer design parameters are determined by modeling the temperature of the foils from which the absorbing matrix is fabricated by using a two-dimensional time-dependent solution of the heat conduction equation. The resulting design will give a steady-state bolometry capability, with approximately 100 Hz time resolution, while simultaneously providing hundreds of channels of spatial information. No wiring harnesses will be required, as the temperature-rise data will be measured via an IR camera. The resulting spatial data may be used to tomographically investigate the profile of plasmas.

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.

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.

Gas electron multiplier (GEM) foil test, repair and effective gain calculation

NASA Astrophysics Data System (ADS)

Tahir, Muhammad; Zubair, Muhammad; Khan, Tufail A.; Khan, Ashfaq; Malook, Asad

2018-06-01

The focus of my research is based on the gas electron multiplier (GEM) foil test, repairing and effective gain calculation of GEM detector. During my research work define procedure of GEM foil testing short-circuit, detection short-circuits in the foil. Study different ways to remove the short circuits in the foils. Set and define the GEM foil testing procedures in the open air, and with nitrogen gas. Measure the leakage current of the foil and applying different voltages with specified step size. Define the Quality Control (QC) tests and different components of GEM detectors before assembly. Calculate the effective gain of GEM detectors using 109Cd and 55Fe radioactive source.

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... Substances Prohibited From Indirect Addition to Human Food Through Food-Contact Surfaces § 189.301 Tin-coated lead foil capsules for wine bottles. (a) Tin-coated lead foil is composed of a lead foil coated on one...

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... Substances Prohibited From Indirect Addition to Human Food Through Food-Contact Surfaces § 189.301 Tin-coated lead foil capsules for wine bottles. (a) Tin-coated lead foil is composed of a lead foil coated on one...

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... Substances Prohibited From Indirect Addition to Human Food Through Food-Contact Surfaces § 189.301 Tin-coated lead foil capsules for wine bottles. (a) Tin-coated lead foil is composed of a lead foil coated on one...

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... Substances Prohibited From Indirect Addition to Human Food Through Food-Contact Surfaces § 189.301 Tin-coated lead foil capsules for wine bottles. (a) Tin-coated lead foil is composed of a lead foil coated on one...

Method for fabricating {sup 99}Mo production targets using low enriched uranium, {sup 99}Mo production targets comprising low enriched uranium

DOEpatents

Wiencek, T.C.; Matos, J.E.; Hofman, G.L.

1997-03-25

A radioisotope production target and a method for fabricating a radioisotope production target is provided, wherein the target comprises an inner cylinder, a foil of fissionable material circumferentially contacting the outer surface of the inner cylinder, and an outer hollow cylinder adapted to receive the substantially foil-covered inner cylinder and compress tightly against the foil to provide good mechanical contact therewith. The method for fabricating a primary target for the production of fission products comprises preparing a first substrate to receive a foil of fissionable material so as to allow for later removal of the foil from the first substrate, preparing a second substrate to receive the foil so as to allow for later removal of the foil from the second substrate; attaching the first substrate to the second substrate such that the foil is sandwiched between the first substrate and second substrate to prevent foil exposure to ambient atmosphere, and compressing the exposed surfaces of the first and second substrate to assure snug mechanical contact between the foil, the first substrate and the second substrate. 3 figs.

Dynamic interference of two anti-phase flapping foils in side-by-side arrangement in an incompressible flow

NASA Astrophysics Data System (ADS)

Bao, Y.; Zhou, D.; Tao, J. J.; Peng, Z.; Zhu, H. B.; Sun, Z. L.; Tong, H. L.

2017-03-01

A two-dimensional computational hydrodynamic model is developed to investigate the propulsive performance of a flapping foil system in viscous incompressible flows, which consists of two anti-phase flapping foils in side-by-side arrangement. In the simulations, the gap between the two foils is varied from 1.0 to 4.0 times of the diameter of the semi-circular leading edge; the amplitude-based Strouhal number is changed from 0.06 to 0.55. The simulations therefore cover the flow regimes from negligible to strong interference in the wake flow. The generations of drag and thrust are investigated as well. The numerical results reveal that the counter-phase flapping motion significantly changes the hydrodynamic force generation and associated propulsive wake. Furthermore, the wake interference becomes important for the case with a smaller foil-foil gap and induces the inverted Bénard von Kármán vortex streets. The results show that the hydrodynamic performance of two anti-phase flapping foils can be significantly different from an isolated pitching foil. Findings of this study are expected to provide new insight for developing hydrodynamic propulsive systems by improving the performance based on the foil-foil interaction.

Evaluating bandgap distributions of carbon nanotubes via scanning electron microscopy imaging of the Schottky barriers.

PubMed

He, Yujun; Zhang, Jin; Li, Dongqi; Wang, Jiangtao; Wu, Qiong; Wei, Yang; Zhang, Lina; Wang, Jiaping; Liu, Peng; Li, Qunqing; Fan, Shoushan; Jiang, Kaili

2013-01-01

We show that the Schottky barrier at the metal-single walled carbon nanotube (SWCNT) contact can be clearly observed in scanning electron microscopy (SEM) images as a bright contrast segment with length up to micrometers due to the space charge distribution in the depletion region. The lengths of the charge depletion increase with the diameters of semiconducting SWCNTs (s-SWCNTs) when connected to one metal electrode, which enables direct and efficient evaluation of the bandgap distributions of s-SWCNTs. Moreover, this approach can also be applied for a wide variety of semiconducting nanomaterials, adding a new function to conventional SEM.

Effects of the foil flatness on the stress-strain characteristics of U10Mo alloy based monolithic mini-plates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hakan Ozaltun; Pavel Medvedev

The effects of the foil flatness on stress-strain behavior of monolithic fuel mini-plates during fabrication and irradiation were studied. Monolithic plate-type fuels are a new fuel form being developed for research and test reactors to achieve higher uranium densities. This concept facilitates the use of low-enriched uranium fuel in the reactor. These fuel elements are comprised of a high density, low enrichment, U–Mo alloy based fuel foil encapsulated in a cladding material made of Aluminum. To evaluate the effects of the foil flatness on the stress-strain behavior of the plates during fabrication, irradiation and shutdown stages, a representative plate frommore » RERTR-12 experiments (Plate L1P756) was considered. Both fabrication and irradiation processes of the plate were simulated by using actual irradiation parameters. The simulations were repeated for various foil curvatures to observe the effects of the foil flatness on the peak stress and strain magnitudes of the fuel elements. Results of fabrication simulations revealed that the flatness of the foil does not have a considerable impact on the post fabrication stress-strain fields. Furthermore, the irradiation simulations indicated that any post-fabrication stresses in the foil would be relieved relatively fast in the reactor. While, the perfectly flat foil provided the slightly better mechanical performance, overall difference between the flat-foil case and curved-foil case was not significant. Even though the peak stresses are less affected, the foil curvature has several implications on the strain magnitudes in the cladding. It was observed that with an increasing foil curvature, there is a slight increase in the cladding strains.« less

Collodion-reinforcement and plasma-cleaning of target foils

NASA Astrophysics Data System (ADS)

Stoner, John O.

2002-03-01

The preparation of evaporated target foils can often be facilitated by use of collodion coatings either on the substrate sides or on the exterior surfaces of the foils. Later, such coatings must usually be removed. Cleaning of a foil is necessary if thin layers of adhesives have crept onto the foil. Removal and/or cleaning can often be done satisfactorily with an oxygen plasma. Apparatus and procedures used for this are described. Foils that were cleaned successfully, and some that were incompatible with the cleaning process are listed.

Studies of PMMA sintering foils with and without coating by magnetron sputtering Pd

NASA Astrophysics Data System (ADS)

Cutroneo, M.; Mackova, A.; Torrisi, L.; Vad, K.; Csik, A.; Ando', L.; Svecova, B.

2017-09-01

Polymethylmethacrylate thin foils were prepared by using physical and chemical processes aimed at changing certain properties. The density and the optical properties were changed obtaining clear and opaque foils. DC magnetron sputtering method was used to cover the foils with thin metallic palladium layers. The high optical absorbent foils were obtained producing microstructured PMMA microbeads with and without thin metallic coatings. Rutherford Backscattering Spectroscopy, optical investigation and microscopy were employed to characterize the prepared foils useful in the field study of laser-matter interaction.

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.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davis, J. S.; Keiter, P. A.; Klein, S. R.

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.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

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.

Neutron sensitivity of 6Li-based suspended foil microstrip neutron detectors using Schott Borofloat® 33 microstrip electrodes

NASA Astrophysics Data System (ADS)

Edwards, Nathaniel S.; Montag, Benjamin W.; Henson, Luke C.; Bellinger, Steven L.; Nichols, Daniel M.; Reichenberger, Michael A.; Fronk, Ryan G.; McGregor, Douglas S.

2018-06-01

6Li foils, each 75-μm thick, were positioned between a Schott Borofloat® 33 microstrip electrode and a planar drift electrode to construct suspended foil microstrip neutron detectors. MCNP6 simulations of two detector configurations, one containing a single 6Li foil and the other containing five 6Li foils, indicated expected maximum intrinsic thermal-neutron detection efficiencies of 18.36% and 54.08%, respectively. For comparison, the intrinsic thermal-neutron detection efficiency as a function of thermal-neutron beam position along the foil span was experimentally measured for both detector configurations. A non-uniform intrinsic thermal-neutron detection efficiency distribution was observed along the span of the 6Li foil(s) between the microstrip and drift electrodes. Maximum intrinsic thermal-neutron detection efficiencies of 12.58 ± 0.15% and 29.75 ± 0.26% for the single and five 6Li foils were measured, respectively. Gamma-ray rejection ratios of 6.46 × 10-5 ± 4.32 × 10-7 and 7.96 × 10-5 ± 4.65 × 10-7 were also measured, respectively, for a 137Cs exposure rate of 50 mR h-1. All measurements were conducted with the 6Li foil(s) contained within a sealed aluminum enclosure pressurized with 10 psig of P-10 gas.

Dual isotope notch observer for isotope identification, assay and imaging with mono-energetic gamma-ray sources

DOEpatents

Barty, Christopher P.J.

2013-02-05

A dual isotope notch observer for isotope identification, assay and imaging with mono-energetic gamma-ray sources includes a detector arrangement consists of three detectors downstream from the object under observation. The latter detector, which operates as a beam monitor, is an integrating detector that monitors the total beam power arriving at its surface. The first detector and the middle detector each include an integrating detector surrounding a foil. The foils of these two detectors are made of the same atomic material, but each foil is a different isotope, e.g., the first foil may comprise U235 and second foil may comprise U238. The integrating detectors surrounding these pieces of foil measure the total power scattered from the foil and can be similar in composition to the final beam monitor. Non-resonant photons will, after calibration, scatter equally from both foils.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

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 ripplemore » 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.« less

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 bottles. (a) Tin-coated lead foil is composed of a lead foil coated on one or both sides with a thin layer...

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.

Characterization of Graphene Stripper Foils in 11-MeV Cyclotrons

NASA Astrophysics Data System (ADS)

Korenev, Sergey; Dishman, Rick; Yebra, Alberto; Meshcheryakov, Nikolay; Smirnov, Ilya; Pavlovsky, Igor; Fink, Richard

An experimental study of the use of graphene as an extractor (stripper) foil in the 11-MeV Siemens Eclipse Cyclotron is discussed in this paper. The main advantage of graphene is its high thermal conductivity compared to that of amorphous carbon films. Graphene also has significant mechanical strength. The lifetime of the graphene foils under proton bombardment exceeded 16,000 μAh. Graphene-based stripper foils demonstrated a significant increase in the transmission factor (defined as the ratio of the beam current on the target to the beam current on the stripper foil), which was approximately 90%. Fabrication of the graphene-based foils is discussed. The pros and cons of using the graphene material as a stripper foil in cyclotrons are analyzed.

Micrometeorite penetration effects in gold foil

NASA Technical Reports Server (NTRS)

Hallgren, D. S.; Radigan, W.; Hemenway, C. L.

1976-01-01

Penetration structures revealed by a Skylab experiment dealing with exposure of single and double layers of 500-800 A thick gold foil to micrometeorites are examined. Examination of all double-layered gold foils revealed that particles producing holes of any type greater than 5 microns in diameter in the first foil break up into many fragments which in turn produce many more holes in the second foil. Evidence of an original particle is not found on any stainless steel plate below the foils, except in one instance. A precise relationship between the size of the event and the mass of the particle producing it could not be determined due to the extreme morphological variety in penetration effects. Fluxes from gold foil and crater experiments are briefly discussed.

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.

DOE Office of Scientific and Technical Information (OSTI.GOV)

CRESSWELL,M.W.; ALLEN,R.A.; GHOSHTAGORE,R.N.

This paper describes the fabrication and measurement of the linewidths of the reference segments of cross-bridge resistors patterned in (100) Bonded and Etched Back Silicon-on-Insulator (BESOI) material. The critical dimensions (CD) of the reference segments of a selection of the cross-bridge resistor test structures were measured both electrically and by Scanning-Electron Microscopy (SEM) cross-section imaging. The reference-segment features were aligned with <110> directions in the BESOI surface material and had drawn linewidths ranging from 0.35 to 3.0 {micro}m. They were defined by a silicon micro-machining process which results in their sidewalls being atomically-planar and smooth and inclined at 54.737{degree} tomore » the surface (100) plane of the substrate. This (100) implementation may usefully complement the attributes of the previously-reported vertical-sidewall one for selected reference-material applications. For example, the non-orthogonal intersection of the sidewalls and top-surface planes of the reference-segment features may alleviate difficulties encountered with atomic-force microscope measurements. In such applications it has been reported that it may be difficult to maintain probe-tip control at the sharp 90{degree} outside corner of the sidewalls and the upper surface. A second application is refining to-down image-processing algorithms and checking instrument performance. Novel aspects of the (100) SOI implementation that are reported here include the cross-bridge resistor test-structure architecture and details of its fabrication. The long-term goal is to develop a technique for the determination of the absolute dimensions of the trapezoidal cross-sections of the cross-bridge resistors' reference segments, as a prelude to developing them for dimensional reference applications. This is believed to be the first report of electrical CD measurements made on test structures of the cross-bridge resistor type that have been patterned in (100) SOI material. The electrical CD results are compared with cross-section SEM measurements made on the same features.« less

From Voxels to Knowledge: A Practical Guide to the Segmentation of Complex Electron Microscopy 3D-Data

PubMed Central

Tsai, Wen-Ting; Hassan, Ahmed; Sarkar, Purbasha; Correa, Joaquin; Metlagel, Zoltan; Jorgens, Danielle M.; Auer, Manfred

2014-01-01

Modern 3D electron microscopy approaches have recently allowed unprecedented insight into the 3D ultrastructural organization of cells and tissues, enabling the visualization of large macromolecular machines, such as adhesion complexes, as well as higher-order structures, such as the cytoskeleton and cellular organelles in their respective cell and tissue context. Given the inherent complexity of cellular volumes, it is essential to first extract the features of interest in order to allow visualization, quantification, and therefore comprehension of their 3D organization. Each data set is defined by distinct characteristics, e.g., signal-to-noise ratio, crispness (sharpness) of the data, heterogeneity of its features, crowdedness of features, presence or absence of characteristic shapes that allow for easy identification, and the percentage of the entire volume that a specific region of interest occupies. All these characteristics need to be considered when deciding on which approach to take for segmentation. The six different 3D ultrastructural data sets presented were obtained by three different imaging approaches: resin embedded stained electron tomography, focused ion beam- and serial block face- scanning electron microscopy (FIB-SEM, SBF-SEM) of mildly stained and heavily stained samples, respectively. For these data sets, four different segmentation approaches have been applied: (1) fully manual model building followed solely by visualization of the model, (2) manual tracing segmentation of the data followed by surface rendering, (3) semi-automated approaches followed by surface rendering, or (4) automated custom-designed segmentation algorithms followed by surface rendering and quantitative analysis. Depending on the combination of data set characteristics, it was found that typically one of these four categorical approaches outperforms the others, but depending on the exact sequence of criteria, more than one approach may be successful. Based on these data, we propose a triage scheme that categorizes both objective data set characteristics and subjective personal criteria for the analysis of the different data sets. PMID:25145678

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.

Explosive-driven, high speed, arcless switch

DOEpatents

Skogmo, P.J.; Tucker, T.J.

1986-05-02

An explosive-actuated, fast-acting arcless switch contains a highly conductive foil to carry high currents positioned adjacent a dielectric surface within a casing. At one side of the foil opposite the dielectric surface is an explosive which, when detonated, drives the conductive foil against the dielectric surface. A pattern of grooves in the dielectric surface ruptures the foil to establish a rupture path having a pattern corresponding to the pattern of the grooves. The impedance of the ruptured foil is greater than that of the original foil to divert high current to a load. Planar and cylindrical embodiments of the switch are disclosed.

Explosive-driven, high speed, arcless switch

DOEpatents

Skogmo, Phillip J.; Tucker, Tillman J.

1987-01-01

An explosive-actuated, fast-acting arcless switch contains a highly conductive foil to carry high currents positioned adjacent a dielectric surface within a casing. At one side of the foil opposite the dielectric surface is an explosive which, when detonated, drives the conductive foil against the dielectric surface. A pattern of grooves in the dielectric surface ruptures the foil to establish a rupture path having a pattern corresponding to the pattern of the grooves. The impedance of the ruptured foil is greater than that of the original foil to divert high current to a load. Planar and cylindrical embodiments of the switch are disclosed.

Experience with a second language affects the use of fundamental frequency in speech segmentation

PubMed Central

Broersma, Mirjam; Cho, Taehong; Kim, Sahyang; Martínez-García, Maria Teresa; Connell, Katrina

2017-01-01

This study investigates whether listeners’ experience with a second language learned later in life affects their use of fundamental frequency (F0) as a cue to word boundaries in the segmentation of an artificial language (AL), particularly when the cues to word boundaries conflict between the first language (L1) and second language (L2). F0 signals phrase-final (and thus word-final) boundaries in French but word-initial boundaries in English. Participants were functionally monolingual French listeners, functionally monolingual English listeners, bilingual L1-English L2-French listeners, and bilingual L1-French L2-English listeners. They completed the AL-segmentation task with F0 signaling word-final boundaries or without prosodic cues to word boundaries (monolingual groups only). After listening to the AL, participants completed a forced-choice word-identification task in which the foils were either non-words or part-words. The results show that the monolingual French listeners, but not the monolingual English listeners, performed better in the presence of F0 cues than in the absence of such cues. Moreover, bilingual status modulated listeners’ use of F0 cues to word-final boundaries, with bilingual French listeners performing less accurately than monolingual French listeners on both word types but with bilingual English listeners performing more accurately than monolingual English listeners on non-words. These findings not only confirm that speech segmentation is modulated by the L1, but also newly demonstrate that listeners’ experience with the L2 (French or English) affects their use of F0 cues in speech segmentation. This suggests that listeners’ use of prosodic cues to word boundaries is adaptive and non-selective, and can change as a function of language experience. PMID:28738093

2 x 2 Polyethylene Reflected and Moderated Highly Enriched Uranium System with Rhenium

DOE Office of Scientific and Technical Information (OSTI.GOV)

A. Nichole Ellis; Jesson Hutchinson; John D. Bess

2010-09-01

The 2 × 2 array HEU-Re experiment was performed on the Planet universal critical assembly machine on November 4th, 2003 at the Los Alamos Critical Experiments Facility (LACEF) at Los Alamos National Laboratory (LANL). For this experiment, there were 10 ½ units, each full unit containing four HEU foils and two rhenium foils. The top unit contained only two HEU foils and two rhenium foils. A total of 42 HEU foils were used for this experiment. Rhenium is a desirable cladding material for space nuclear power applications. This experiment consisted of HEU foils interleaved with rhenium foils and is moderatedmore » and reflected by polyethylene plates. A unit consisted of a polyethylene plate, which has a recess for rhenium foils, and four HEU foils in a single layer in the top recess of each polyethylene plate. The Planet universal criticality assembly machine has been previously used in experiments containing HEU foils interspersed with SiO2 (HEU-MET-THERM-001), Al (HEU-MET-THERM-008), MgO (HEU-MET-THERM-009), Gd foils (HEU-MET-THERM-010), 2 × 2 × 26 Al (HEU-MET-THERM-012), Fe (HEU-MET-THERM-013 and HEU-MET-THERM-015), 2 × 2 × 23 SiO2 (HEU-MET-THERM-014), 2 × 2 × 11 hastalloy plates (HEU-MET-THERM-016), and concrete (HEU-MET-THERM-018). The 2 × 2 array of HEU-Re is considered acceptable for use as a benchmark critical experiment.« less

ERPs While Judging Meaningfulness of Sentences with and without Homonym or Morpheme Spelling Foils: Comparing 4th to 9th Graders with and without Spelling Disabilities

PubMed Central

Richards, Todd; Pettet, Mark; Askren, Katie; Grabowski, Tom; Yagle, Kevin; Wallis, Peter; Northey, Mary; Abbott, Robert; Berninger, Virginia

2016-01-01

Thirteen students with and twelve students without spelling disabilities judged whether sentences (1/3 all correct spellings, 1/3 with homonym foil, 1/3 with morpheme foil) were meaningful while event-related potentials (ERPs) were measured with EGI Geodesic EEG System 300 (128-channel hydro-cell nets). For N400, Rapid Automatic Switching (RAS) correlated with comprehending sentences with homonym foils in control group but with morpheme foils in SLD group. For P600, dictated spelling correlated with comprehending sentences with morpheme foils in the control group but solving anagrams with homonym foils in the SLD group. Educational significance and neuropsychological significance of these contrasting results are discussed. PMID:28657362

Preparation and Physical Properties of Segmented Thermoelectric YBa2Cu3O7-x -Ca3Co4O9 Ceramics

NASA Astrophysics Data System (ADS)

Wannasut, P.; Keawprak, N.; Jaiban, P.; Watcharapasorn, A.

2018-01-01

Segmented thermoelectric ceramics are now well known for their high conversion efficiency and are currently being investigated in both basic and applied energy researches. In this work, the successful preparation of the segmented thermoelectric YBa2Cu3O7-x -Ca3Co4O9 (YBCO-CCO) ceramic by hot pressing method and the study on its physical properties were presented. Under the optimum hot pressing condition of 800 °C temperature, 1-hour holding time and 1-ton weight, the segmented YBCO-CCO sample showed two strongly connected layers with the relative density of about 96%. The X-ray diffraction (XRD) patterns indicated that each segment showed pure phase corresponding to each respective composition. Scanning electron microscopy (SEM) results confirmed the sharp interface and good adhesion between YBCO and CCO layers. Although the chemical analysis indicated the limited inter-layer diffusion near the interface, some elemental diffusion at the boundary was expected to be the source of this strong bonding.

Effects of the shape of the foil corners on the irradiation performance of U10Mo alloy based monolithic mini-plates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ozaltun, Hakan; Medvedev, Pavel G

2015-06-01

Monolithic plate-type fuel is a fuel form being developed for high performance research and test reactors to minimize the use of enriched material. These fuel elements are comprised of a high density, low enrichment, U-Mo alloy based fuel foil, sandwiched between Zirconium liners and encapsulated in Aluminum cladding. The use of a high density fuel in a foil form presents a number of fabrication and operational concerns, such as: foil centering, flatness of the foil, fuel thickness variation, geometrical tilting, foil corner shape etc. To benchmark this new design, effects of various geometrical and operational variables on irradiation performance havemore » been evaluated. As a part of these series of sensitivity studies, the shape of the foil corners were studied. To understand the effects of the corner shapes of the foil on thermo-mechanical performance of the plates, a behavioral model was developed for a selected plate from RERTR-12 experiments (Plate L1P785). Both fabrication and irradiation processes were simulated. Once the thermo-mechanical behavior the plate is understood for the nominal case, the simulations were repeated for two additional corner shapes to observe the changes in temperature, displacement and stress-strain fields. The results from the fabrication simulations indicated that the foil corners do not alter the post-fabrication stress-strain magnitudes. Furthermore, the irradiation simulations revealed that post-fabrication stresses of the foil would be relieved very quickly in operation. While, foils with chamfered and filleted corners yielded stresses with comparable magnitudes, they are slightly lower in magnitudes, and provided a more favorable mechanical response compared with the foil with sharp corners.« less

An anti-neutrino detector to monitor nuclear reactor's power and fuel composition

NASA Astrophysics Data System (ADS)

Battaglieri, M.; DeVita, R.; Firpo, G.; Neuhold, P.; Osipenko, M.; Piombo, D.; Ricco, G.; Ripani, M.; Taiuti, M.

2010-05-01

In this contribution, we present the expected performance of a new detector to measure the absolute energy-integrated flux and the energy spectrum of anti-neutrinos emitted by a nuclear power plant. The number of detected anti-neutrino is a direct measure of the power while from the energy spectrum is possible to infer the evolution in time of the core isotopic composition. The proposed method should be sensitive to a sudden change in the core burn-up as caused, for instance, by a fraudulent subtraction of plutonium. The detector, a 130×100×100 cm3 cube with 1 m3 active volume, made by plastic scintillator wrapped in thin Gd foils, is segmented in 50 independent optical channels read, side by side, by a pair of 3 in. photomultipliers. Anti-neutrino interacts with hydrogen contained in the plastic scintillator via the neutron inverse β- decay ( ν¯p→e+n). The high segmentation of the detector allows to reduce the background from other reactions by detecting independent hits for the positron, the two photons emitted in the e+e- annihilation and the neutron.

Design of 95 GHz gyrotron based on continuous operation copper solenoid with water cooling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Borodin, Dmitri; Ben-Moshe, Roey; Einat, Moshe

2014-07-15

The design work for 2nd harmonic 95 GHz, 50 kW gyrotron based on continuous operation copper solenoid is presented. Thermionic magnetron injection gun specifications were calculated according to the linear trade off equation, and simulated with CST program. Numerical code is used for cavity design using the non-uniform string equation as well as particle motion in the “cold” cavity field. The mode TE02 with low Ohmic losses in the cavity walls was chosen as the operating mode. The Solenoid is designed to induce magnetic field of 1.8 T over a length of 40 mm in the interaction region with homogeneitymore » of ±0.34%. The solenoid has six concentric cylindrical segments (and two correction segments) of copper foil windings separated by water channels for cooling. The predicted temperature in continuous operation is below 93 °C. The parameters of the design together with simulation results of the electromagnetic cavity field, magnetic field, electron trajectories, and thermal analyses are presented.« less

Production of thin glass mirrors by hot slumping for x-ray telescopes: present process and ongoing development

NASA Astrophysics Data System (ADS)

Salmaso, B.; Basso, S.; Brizzolari, C.; Civitani, M.; Ghigo, M.; Pareschi, G.; Spiga, D.; Tagliaferri, G.; Vecchi, G.

2014-07-01

Thin glass foils are considered good candidates to build a segmented X-ray telescope with effective area as large as 2 m2 and angular resolution better than 5 arcsec. In order to produce thin glass mirror segments, we developed a direct hot slumping technique assisted by pressure, in which the shape of a mould is replicated onto the optical surface of the glass. In this paper we present the result obtained with AF32 (by Schott) and EAGLE XG (by Corning) glass types. The selected mould material is Zerodur K20, as it does not require any anti-sticking layer and has a good matching, in terms of Coefficient of Thermal Expansion, with both glass types. Our group already produced a few prototypes, reaching angular resolution near 20 arcsec. In this work, relevant steps forward aimed at attaining a 5 arcsec angular resolution are described, along with the tuning of few key parameters in the slumping process. The results obtained on a newly procured cylindrical Zerodur K20 mould are presented.

Fabrication of flower-like micro/nano dual scale structured copper oxide surfaces: Optimization of self-cleaning properties via Taguchi design

NASA Astrophysics Data System (ADS)

Moosavi, Saeideh Sadat; Norouzbeigi, Reza; Velayi, Elmira

2017-11-01

In the present work, copper oxide superhydrophobic surface is fabricated on a copper foil via the chemical bath deposition (CBD) method. The effects of some influential factors such as initial concentrations of Cu (II) ions and the surface energy modifier, solution pH, reaction and modification steps time on the wettability property of copper oxide surface were evaluated using Taguchi L16 experimental design. Results showed that the initial concentration of Cu (II) has the most significant impact on the water contact angle and wettability characteristics. The XRD, SEM, AFM and FTIR analyses were used to characterize the copper oxide surfaces. The Water contact angle (WCA) and contact angle hysteresis (CAH) were also measured. The SEM results indicated the formation of a flower-like micro/nano dual-scale structure of copper oxide on the substrate. This structure composed of numerous nano-petals with a thickness of about 50 nm. As a result, a copper oxide hierarchical surface with WCA of 168.4°± 3.5° and CAH of 2.73° exhibited the best superhydrophobicity under proposed optimum condition. This result has been obtained just by 10 min hydrolysis reaction. Besides, this surface showed a good stability under acidic and saline conditions.

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.

The dissimilar brazing of Kovar alloy to SiCp/Al composites using silver-based filler metal foil

NASA Astrophysics Data System (ADS)

Wang, Peng; Xu, Dongxia; Zhai, Yahong; Niu, Jitai

2017-09-01

Aluminum metal matrix composites with high SiC content (60 vol.% SiCp/Al MMCs) were surface metallized with a Ni-P alloy coating, and vacuum brazing between the composites and Kovar alloy were performed using rapidly cooled Ag-22.0Cu-15.9In-10.86Sn-1.84Ti (wt%) foil. The effects of Ni-P alloy coating and brazing parameters on the joint microstructures and properties were researched by SEM, EDS, and single lap shear test, respectively. Results show that Ag-Al intermetallic strips were formed in the 6063Al matrix and filler metal layer because of diffusion, and they were arranged regularly and accumulated gradually as the brazing temperature was increased ( T/°C = 550-600) or the soaking time was prolonged ( t/min = 10-50). However, excessive strips would destroy the uniformity of seams and lead to a reduced bonding strength (at most 70 MPa). Using a Ni-P alloy coating, void free joints without those strips were obtained at 560 °C after 20 min soaking time, and a higher shear strength of 90 MPa was achieved. The appropriate interface reaction ( 2 μm transition layer) that occurred along the Ni-P alloy coating/filler metal/Kovar alloy interfaces resulted in better metallurgical bonding. In this research, the developed Ag-based filler metal was suitable for brazing the dissimilar materials of Ni-P alloy-coated SiCp/Al MMCs and Kovar alloy, and capable welding parameters were also broadened.

Detection of surface carbon and hydrocarbons in hot spot regions of niobium superconducting rf cavities by Raman spectroscopy

DOE PAGES

Cao, C.; Argonne National Lab.; Ford, D.; ...

2013-06-26

Raman microscopy/spectroscopy measurements are presented on high purity niobium (Nb) samples, including pieces from hot spot regions of a tested superconducting rf cavity that exhibit a high density of etch pits. Measured spectra are compared with density functional theory calculations of Raman-active, vibrational modes of possible surface Nb-O and Nb-H complexes. The Raman spectra inside particularly rough pits in all Nb samples show clear differences from surrounding areas, exhibiting enhanced intensity and sharp peaks. While some of the sharp peaks are consistent with calculated NbH and NbH 2 modes, there is better overall agreement with C-H modes in chain-type hydrocarbons.more » Other spectra reveal two broader peaks attributed to amorphous carbon. Niobium foils annealed to >2000°C in high vacuum develop identical Raman peaks when subjected to cold working. Regions with enhanced C and O have also been found by SEM/EDX spectroscopy in the hot spot samples and cold-worked foils, corroborating the Raman results. Such regions with high concentrations of impurities are expected to suppress the local superconductivity and this may explain the correlation between hot spots in superconducting rf (SRF) cavities and the observation of a high density of surface pits. Finally, the origin of localized high carbon and hydrocarbon regions is unclear at present but it is suggested that particular processing steps in SRF cavity fabrication may be responsible.« less

Detection of surface carbon and hydrocarbons in hot spot regions of niobium superconducting rf cavities by Raman spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cao, C.; Argonne National Lab.; Ford, D.

Raman microscopy/spectroscopy measurements are presented on high purity niobium (Nb) samples, including pieces from hot spot regions of a tested superconducting rf cavity that exhibit a high density of etch pits. Measured spectra are compared with density functional theory calculations of Raman-active, vibrational modes of possible surface Nb-O and Nb-H complexes. The Raman spectra inside particularly rough pits in all Nb samples show clear differences from surrounding areas, exhibiting enhanced intensity and sharp peaks. While some of the sharp peaks are consistent with calculated NbH and NbH 2 modes, there is better overall agreement with C-H modes in chain-type hydrocarbons.more » Other spectra reveal two broader peaks attributed to amorphous carbon. Niobium foils annealed to >2000°C in high vacuum develop identical Raman peaks when subjected to cold working. Regions with enhanced C and O have also been found by SEM/EDX spectroscopy in the hot spot samples and cold-worked foils, corroborating the Raman results. Such regions with high concentrations of impurities are expected to suppress the local superconductivity and this may explain the correlation between hot spots in superconducting rf (SRF) cavities and the observation of a high density of surface pits. Finally, the origin of localized high carbon and hydrocarbon regions is unclear at present but it is suggested that particular processing steps in SRF cavity fabrication may be responsible.« less

Penetration of multiple thin films in micrometeorite capture cells

NASA Technical Reports Server (NTRS)

Simon, Charles G.

1994-01-01

As part of a continuing effort to develop cosmic dust detectors/collectors for use in space, we performed a series of hypervelocity impact experiments on combined sensor/capture-cell assemblies using 10-200-micron-diameter glass projectiles and olivine crystals at velocities of 0.9-14.4 km/s. The design objective of the space-flight instrument is to measure the trajectories of individual particles with sufficient accuracy to permit identification of their parent bodies and to capture enough impactor material to allow chemical and isotopic analyses of samples returned to Earth. Three different multiple-film small-particle capture cell designs (0.1-100-micron-thick Al foils with approx. 10, 100, and 1800 micron spacing) were evaluated for their ability to capture impactor fragments and residue. Their performances were compared to two other types of capture cells, foil covered Ge crystals, and 0.50 and 0.120 g/cu cm aerogels. All capture cells were tested behind multifilm (1.4-6.0-micron-thick) polyvinylidene fluoride (PVDF) velocity/trajectory sensor devices. Several tests were also done without the PVDF sensors for comparison. The results of this study were reported by Simon in a comprehensive report in which the morphology of impacts and impactor residues in various types of capture cells after passage through two PVDF sensor films is discussed. Impactor fragments in selected capture cells from impacts at velocities up to 6.4 km/s were identified using scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS).

Characterization of Beryllium Windows for Coherent X-ray Optics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goto, Shunji; Yabashi, Makina; Tamasaku, Kenji

2007-01-19

Beryllium foils fabricated by several processes were characterized using spatially coherent x rays at 1-km beamline of SPring-8. By thickness dependence of bright x-ray spot density due to Fresnel diffraction from several-micron deficiencies, we found that speckles (bright x-ray spots) were due to voids with densities 103-104 mm-3 in powder foils and ingot foils. Compared with powder and ingot foils, a polished physical-vapor-deposited (PVD) beryllium foil gave highly uniform beams with no speckles. The PVD process eliminates the internal voids in principle and the PVD foil is the best for coherent x-ray applications.

Development, characterization and qualification of first GEM foils produced in India

NASA Astrophysics Data System (ADS)

Shah, Aashaq; Ahmed, Asar; Gola, Mohit; Sharma, Ram Krishna; Malhotra, Shivali; Kumar, Ashok; Naimuddin, Md.; Menon, Pradeep; Srinivasan, K.

2018-06-01

The increasing demand for Gas Electron Multiplier (GEM) foils has been driven by their application in many current and proposed high-energy physics experiments. Micropack, a Bengaluru-based company, has established and commercialized GEM foils for the first time in India. Micropack used the double-mask etching technique to successfully produce 10 cm × 10 cm GEM foil. In this paper, we report on the development as well as the geometrical and electrical properties of these foils, including the size uniformity of the holes and leakage current measurements. Our characterization studies show that the foils are of good quality and satisfy all the necessary quality control criteria.

Explosive-driven, high speed, arcless switch

DOEpatents

Skogmo, P.J.; Tucker, T.J.

1987-07-14

An explosive-actuated, fast-acting arcless switch contains a highly conductive foil to carry high currents positioned adjacent a dielectric surface within a casing. At one side of the foil opposite the dielectric surface is an explosive which, when detonated, drives the conductive foil against the dielectric surface. A pattern of grooves in the dielectric surface ruptures the foil to establish a rupture path having a pattern corresponding to the pattern of the grooves. The impedance of the ruptured foil is greater than that of the original foil to divert high current to a load. Planar and cylindrical embodiments of the switch are disclosed. 7 figs.

Laser-driven flyer plate

DOEpatents

Paisley, Dennis L.

1991-01-01

Apparatus for producing high velocity flyer plates involving placing a layer of dielectric material between a first metal foil and a second metal foil. With laser irradiation through an optical substrate, the first metal foil forms a plasma in the area of the irradiation, between the substrate and the solid portion of the first metal foil. When the pressure between the substrate and the foil reaches the stress limit of the dielectric, the dielectric will break away and launch the flyer plate out of the second metal foil. The mass of the flyer plate is controlled, as no portion of the flyer plate is transformed into a plasma.

Quasi-static analysis of foil journal bearings for a Brayton cycle turboalternator

NASA Technical Reports Server (NTRS)

Eshel, A.

1974-01-01

A quasi-static analysis is presented for foil journal bearings designed for a NASA Brayton Cycle Turboalternator. Included in the analysis are effects of 'slack' (due to flexural rigidity of the foil), of frictionally restrained extension of the foil-length in contact with cylindrical guides, of fluid inertia and compressibility, and of thermal expansion of rotor, foil and supporting structure. Comparisons are made with results of early experiments performed by Licht (1968, 1969) and recent data of Licht and Branger (1973). Variatons of film thickness, foil tension and bearing stiffness are presented graphically as functions of pertinent parameters for the case of operation in zero-gravity environment.

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.

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

Effect of Circuit Inductance on Ceramics Joining by Titanium Foil Explosion

NASA Astrophysics Data System (ADS)

Takada, Yoshihiro; Takaki, Koichi; Itagaki, Minoru; Mukaigawa, Seiji; Fujiwara, Tamiya; Ohshima, Shuzo; Takahashi, Ikuo; Kuwashima, Takayuki

This article describes the influences of circuit inductance on alumina (Al2O3) tile joining using explosive titanium foil. Several kAs pulse current was supplied from 8.28 µF storage capacitor to the 50 µm thickness titanium foil which was sandwiched between the Al2O3 tiles with pressure of 8.3 MPa. The temperature of the foil was rapidly increased owing to ohmic heating with the large current, and then the foil was liquefied and vaporized. The Al2O3 tiles were successfully bonded when the input energy to the titanium foil was higher than the energy required for the foil vaporization. The bonding strength increases with increasing the energy input to the foil. However, the foil explosion cracked the tiles when the input energy exceeds a critical value. Increasing the circuit inductance from 1.13 µH to 64.8 µH, the critical energy of tile cracking increase from 160 J to 507 J, respectively. the maximum bonding strength of 330 kg was obtained when the circuit inductance was 21.8 µH. An investigation of the interfacial structure of the joints using electron probe micro-analysis revealed that distinct reaction areas existed in the interlayer.

High-performance lithium-ion batteries with 1.5 μm thin copper nanowire foil as a current collector

NASA Astrophysics Data System (ADS)

Chu, Hsun-Chen; Tuan, Hsing-Yu

2017-04-01

Cu Foil, a thin sheet of Cu, is the common anode current collector in commercial lithium ion batteries (LIBs) which accounts for ∼ 10 wt% of the total cell weight. However, thickness reduction of LIB-based Cu foils below 6 μm has been limited by the incapability of conventional rolling annealing or electrodeposition process. We here report a new type of Cu foil, so called Cu nanowire foil (CuNW foil), for use as an LIB anode current collector. We fabricate Cu NW foils by rolling press Cu nanowire fabric to reduce the thickness down to ∼1.5 μm with an areal weight down to ∼1.2 mg cm-2 and a density approximately 96% to that of bulk Cu. The rough surface and porous structure of CuNW foil enable better wetting and adhering properties of graphite slurry on foil. In full cell examination, a cell of a areal capacity of 3 mAh cm-2 exhibits 83.6% capacity retention for 600 cycles at 0.6 C that meets the standard specification of most commercial LIBs. As a proof-of-concept of demonstration, we fabricate a 700 mA pouch-type battery implemented with graphite-Cu NWs foil anodes to serve as energy supply to operate electronic devices.

Characteristics of a plasma flow field produced by a metal array bridge foil explosion

NASA Astrophysics Data System (ADS)

Junying, WU; Long, WANG; Yase, LI; Lijun, YANG; Manzoor, SULTAN; Lang, CHEN

2018-07-01

To improve the energy utilization efficiency of metal bridge foil explosion, and increase the function range of plasmas, array bridge foil explosion experiments with different structures were performed. A Schlieren photographic measurement system with a double-pulse laser source was used to observe the flow field of a bridge foil explosion. The evolution laws of plasmas and shock waves generated by array bridge foil explosions of different structures were analyzed and compared. A multi-phase flow calculation model was established to simulate the electrical exploding process of a metal bridge foil. The plasma equation of state was determined by considering the effect of the changing number of particles and Coulomb interaction on the pressure and internal energy. The ionization degree of the plasma was calculated via the Saha–Eggert equation assuming conditions of local thermal equilibrium. The exploding process of array bridge foils was simulated, and the superposition processes of plasma beams were analyzed. The variation and distribution laws of the density, temperature, pressure, and other important parameters were obtained. The results show that the array bridge foil has a larger plasma jet diameter than the single bridge foil for an equal total area of the bridge foil. We also found that the temperature, pressure, and density of the plasma jet’s center region sharply increase because of the superposition of plasma beams.

Nickel-Graphite Composite Compliant Interface and/or Hot Shoe Material

NASA Technical Reports Server (NTRS)

Firdosy, Samad A.; Chun-Yip Li, Billy; Ravi, Vilupanur A.; Fleurial, Jean-Pierre; Caillat, Thierry; Anjunyan, Harut

2013-01-01

Next-generation high-temperature thermoelectric-power-generating devices will employ segmented architectures and will have to reliably withstand thermally induced mechanical stresses produced during component fabrication, device assembly, and operation. Thermoelectric materials have typically poor mechanical strength, exhibit brittle behavior, and possess a wide range of coefficient of thermal expansion (CTE) values. As a result, the direct bonding at elevated temperatures of these materials to each other to produce segmented leg components is difficult, and often results in localized microcracking at interfaces and mec hanical failure due to the stresses that arise from the CTE mismatch between the various materials. Even in the absence of full mechanical failure, degraded interfaces can lead to increased electrical and thermal resistances, which adversely impact conversion efficiency and power output. The proposed solution is the insertion of a mechanically compliant layer, with high electrical and thermal conductivity, between the low- and high-temperature segments to relieve thermomechanical stresses during device fabrication and operation. This composite material can be used as a stress-relieving layer between the thermoelectric segments and/or between a thermoelectric segment and a hot- or cold-side interconnect material. The material also can be used as a compliant hot shoe. Nickel-coated graphite powders were hot-pressed to form a nickel-graphite composite material. A freestanding thermoelectric segmented leg was fabricated by brazing the compliant pad layer between the high-temperature p- Zintl and low-temperature p-SKD TE segments using Cu-Ag braze foils. The segmented leg stack was heated in vacuum under a compressive load to achieve bonding. The novelty of the innovation is the use of composite material that re duces the thermomechanical stresses en - countered in the construction of high-efficiency, high-temperature therm - o-electric devices. The compliant pad enables the bonding of dissimilar thermoelectric materials while maintaining the desired electrical and thermal properties essential for efficient device operation. The modulus, CTE, electrical, and thermal conductances of the composite can be controlled by varying the ratio of nickel to graphite.

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.

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.

Prediction and characterization of heat-affected zone formation due to neighboring nickel-aluminum multilayer foil reaction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adams, David P.; Hirschfeld, Deidre A.; Hooper, Ryan J.

2015-09-01

Reactive multilayer foils have the potential to be used as local high intensity heat sources for a variety of applications. Much of the past research effort concerning these materials have focused on understanding the structure-property relationships of the foils that govern the energy released during a reaction. To enhance the ability of researchers to more rapidly develop technologies based on reactive multilayer foils, a deeper and more predictive understanding of the relationship between the heat released from the foil and microstructural evolution in the neighboring materials is needed. This work describes the development of a numerical model for the purposemore » of evaluating new foil-substrate combinations for screening and optimization. The model is experimentally validated using a commercially available Ni-Al multilayer foils and different alloys.« less

Polymer gel dosimetry for measuring the dose near thin high-Z materials irradiated with high energy photon beams.

PubMed

Warmington, Leighton L; Gopishankar, N; Broadhurst, John H; Watanabe, Yoichi

2016-12-01

To investigate the feasibility of three-dimensional (3D) dose measurements near thin high-Z materials placed in a water-like medium by using a polymer gel dosimeter (PGD) when the medium was irradiated with high energy photon beams. PGD is potentially a useful tool for this application because it can record the dose around a small object made of a high-Z material in a continuous 3D medium. In this study, the authors manufactured a methacrylic acid-based normoxic PGD, nMAG. Two 0.5 mm thick lead foils (1 × 1 cm) were placed in foil supports with 0.7 cm separation in a 1000 ml polystyrene container filled with nMAG. The authors used two foil configurations, i.e., orthogonal and parallel. In the orthogonal configuration, two foils were placed in the direction orthogonal to the beam axis. The parallel configuration had two foils arranged in parallel to the beam axis. The phantom was irradiated with an 18 MV photon beam of 5 × 5 cm field size. It was imaged with a three-Tesla (3 T) magnetic resonance imaging (MRI) scanned using the Car-Purcell-Meiboom-Gill pulse sequence. The spin-spin relaxation time (R2) to-dose calibration data were obtained by using small vials filled with nMAG and exposing to known doses. The DOSXYZnrc Monte Carlo (MC) code was used to get the expected dose distributions. More than 35 × 10 6 of histories were simulated so that the average error was less than 1%. An in-house matlab-based software was used to obtain the dose distributions from the measured R2 data as well as to compare the measurements and the MC predictions. The dose change due to the presence of the foils was studied by comparing the dose distributions with and without foils (or the reference). For the orthogonal configuration, the measured dose along the beam axis showed an increase in the upstream side of the first foil, between the foils, and on the downstream side of the second foil. The range of increased dose area was 1.1 cm in the upstream of the first foil. However, in the downstream of the second foil, it was 0.2 cm, beyond which the dose fell below the reference dose by 10%. The dose profile between the foils showed a well-like shape with the minimum dose still larger than the reference dose by 1.8%. The minimum dose point was closer to the first foil than to the second foil. For the parallel configuration, the dose between foils was the largest at the center. The increased dose area opposite to the gap between foils extended outward to 1 cm. The spatial dose distributions of PGD and MC showed the same geometrical patterns except for the points inside the foils for both orthogonal and parallel foil arrangements. The authors demonstrated that the nMAG PGD with MRI could be used to measure the 3D dosimetric structures at the mm-scale in the vicinity of the foil. The current study provided more accurate 3D spatial dose distribution than the previous studies. Furthermore, the measurements were validated by the MC simulation.

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.

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.

Boron stripper foils for particle accelerators

NASA Astrophysics Data System (ADS)

Zeisler, Stefan K.; Brigham, Michael; Kaur, Ishneet; Jaggi, Vinder

2018-05-01

Micromatter Technologies Inc., now located in Surrey B.C., Canada, is a worldwide supplier of pure and boron containing diamond-like carbon (DLC) stripper foils ranging from 10 nm to 10 μm. These foils are manufactured in-house using pulsed laser deposition. Continuing our research into novel production methods and alternative materials to be used as beam strippers for heavy elements and in particular for tandem particle accelerators, pure boron foils were prepared by laser plasma ablation of a disc shaped boron sputter target. Foil thickness between 10 nm to approximately 0.7 μm were achieved. The new boron foils showed considerably less stress, higher mechanical strength and better flexibility than comparable DLC films.

NMR of samples containing metal foils.

PubMed

Xiong, J; Lock, H; Tao, T; Keeler, C; Maciel, G E

1999-07-01

By using spool configurations of a sample containing aluminum foil, in which the axis of the spool is collinear with the RF coil axis, one can obtain high-quality 13C NMR spectra of static samples of organic material attached to the aluminum foil. By combining such a spool configuration (or, alternatively, analogous samples containing equivalent amounts of fine aluminum powder) with the magic-angle hopping (MAH) technique, one can achieve a high degree of isotropic averaging of the 13C spectrum. This opens to NMR techniques the study of a variety of samples containing macroscopic pieces of metal foils, e.g., thin films deposited on metal foils and electrochemical systems with species adsorbed on metal-foil electrodes.

Development of aerodynamic foil journal bearings for a high speed cryogenic turboexpander

NASA Astrophysics Data System (ADS)

Xiong, L.-Y.; Wu, G.; Hou, Y.; Liu, L.-Q.; Ling, M.-F.; Chen, C.-Z.

The research presented in this paper is aimed at the development of aerodynamic foil journal bearings applying to a small high speed cryogenic turboexpander. A small high speed cryogenic turboexpander is designed. Attention has been paid to the study of the effect of foil stiffness on the vibration performance of bearings. From rotation tests, it is clear that, with the proper choice of foil stiffness, the foil bearing presented here can possess sufficiently high stability. The maximum rotational speed obtained is greater than 230 000 rpm. Therefore, owing to its simplicity and high performance, this type of foil journal bearing can hopefully be applied to a small high speed cryogenic turboexpander.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mamedov, Fadahat; Štekl, Ivan; Smolek, Karel

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 themore » 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.« less

Electrochemical Corrosion Properties of Commercial Ultra-Thin Copper Foils

NASA Astrophysics Data System (ADS)

Yen, Ming-Hsuan; Liu, Jen-Hsiang; Song, Jenn-Ming; Lin, Shih-Ching

2017-08-01

Ultra-thin electrodeposited Cu foils have been developed for substrate thinning for mobile devices. Considering the corrosion by residual etchants from the lithography process for high-density circuit wiring, this study investigates the microstructural features of ultra-thin electrodeposited Cu foils with a thickness of 3 μm and their electrochemical corrosion performance in CuCl2-based etching solution. X-ray diffraction and electron backscatter diffraction analyses verify that ultra-thin Cu foils exhibit a random texture and equi-axed grains. Polarization curves show that ultra-thin foils exhibit a higher corrosion potential and a lower corrosion current density compared with conventional (220)-oriented foils with fan-like distributed fine-elongated columnar grains. Chronoamperometric results also suggest that ultra-thin foils possess superior corrosion resistance. The passive layer, mainly composed of CuCl and Cu2O, forms and dissolves in sequence during polarization.

Copper foils with gradient structure in thickness direction and different roughnesses on two surfaces fabricated by double rolling

NASA Astrophysics Data System (ADS)

Wang, Xi-yong; Liu, Xue-feng; Zou, Wen-jiang; Xie, Jian-xin

2013-12-01

Copper foils with gradient structure in thickness direction and different roughnesses on two surfaces were fabricated by double rolling. The two surface morphologies of double-rolled copper foils are quite different, and the surface roughness values are 61 and 1095 nm, respectively. The roughness value of matt surface can meet the requirement for bonding the resin matrix with copper foils used for flexible printed circuit boards, thus may omit traditional roughening treatment; the microstructure of double-rolled copper foils demonstrates an obviously asymmetric gradient feature. From bright surface to matt surface in thickness direction, the average grain size first increases from 2.3 to 7.4 μm and then decreases to 3.6 μm; compared with conventional rolled copper foils, the double-rolled copper foils exhibit a remarkably increased bending fatigue life, and the increased range is about 16.2%.

Experimental study of the spatial distributions of relativistic electron beams reflected and refracted by a thin foil

DOE Office of Scientific and Technical Information (OSTI.GOV)

Serov, A. V., E-mail: serov@x4u.lebedev.ru; Mamonov, I. A.

2016-08-15

Photographs of cross sections of an electron beam scattered from thin foils have been obtained on a dosimetric film. The procession of images makes it possible to obtain the spatial distribution of particles both reflected from a foil and passed through it. The spatial distribution of electrons incident on aluminum, copper, and lead foils, as well as on bimetallic foils composed of aluminum and lead layers and of aluminum and copper layers, has been measured. The effect of the material and thickness of the foil, as well as of the angle between the initial beam trajectory and the target plane,more » on the spatial distribution of electrons has been studied. The effect of the sequence of the metal layers in bimetallic foils on the distribution of beams has been analyzed. A 7.4-MeV microtron has been used as a source of electrons.« less

Development of Gating Foils To Inhibit Ion Feedback Using FPC Production Techniques

NASA Astrophysics Data System (ADS)

Arai, D.; Ikematsu, K.; Sugiyama, A.; Iwamura, M.; Koto, A.; Katsuki, K.; Fujii, K.; Matsuda, T.

2018-02-01

Positive ion feedback from a gas amplification device to the drift region of the Time Projection Chamber for the ILC can deteriorate the position resolution. In order to inhibit the feedback ions, MPGD-based gating foils having good electron transmission have been developed to be used instead of the conventional wire gate. The gating foil needs to control the electric field locally in opening or closing the gate. The gating foil with a GEM (gas electron multiplier)-like structure has larger holes and smaller thickness than standard GEMs for gas amplification. It is known that the foil transmits over 80 % of electrons and blocks ions almost completely. We have developed the gating foils using flexible printed circuit (FPC) production techniques including an improved single-mask process. In this paper, we report on the production technique of 335 μm pitch, 12.5 μm thick gating foil with 80 % transmittance of electrons in ILC conditions.

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.

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.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edwards, Danny J.; Ermi, Ruby M.; Schemer-Kohrn, Alan L.

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 revealedmore » 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.« less

Pulsed electric discharge laser technology. Electron beam window foil material

NASA Astrophysics Data System (ADS)

McGeoch, M. W.; Defuria, A. J.; Pike, C. T.

1984-01-01

An experimental and theoretical study of titanium alloy foil windows is described. The alloys considered are Ti 15-3-3-3, Ti 3-2.5, and CP Ti(4). The foil thickness ranges from 0.5 mil to 1.0 mil. Tensile strength data is presented for 75 F and 600 F. High-cycle (10 to the 7th power) fatigue data is presented to Ti 15-3-3-3 and Ti 3-2.5 at 75 F and 600 F. Crystal structures are shown for all the alloys. Measurements of the biaxial, or membrane, strength of the alloys is presented. A simulation of laser pulsed overpressure conditions is described, and the foil fatigue under these conditions is documented. The stresses in pressure loaded foil windows were calculated by the finite element method, both for static and dynamic loading. The shape of the foil support rib was optimized to minimize the foil stresses. A correlation was performed between the computed stress cycling under pulsed loading and the measured fatigue strength in uniaxial tension. As a check on the pulse simulation, the actual movement of an electron-beam foil window was measured by interferometry. A speckle interferometer which allows measurement of the movement of unpolished foil surfaces is described.

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.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vivek, A., E-mail: vivek.4@osu.edu; 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 Dopplermore » 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.« less

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.

In-line beam current monitor

DOEpatents

Ekdahl, Jr., Carl A.; Frost, Charles A.

1986-01-01

An intense relativistic electron beam current monitor for a gas neutralized beam transport line includes a first foil for conducting plasma current to the wall where it is measured as it traverses an inductive loop formed by a cavity in the wall. An insulator foil separates the first foil from a second conducting foil which returns the current to the plasma environment.

In-line beam current monitor

DOEpatents

Ekdahl, C.A. Jr.; Frost, C.A.

1984-11-13

An intense relativistic electron beam current monitor for a gas neutralized beam transport line includes a first foil for conducting plasma current to the wall where it is measured as it traverses an inductive loop formed by a cavity in the wall. An insulator foil separates the first foil from a second conducting foil which returns the current to the plasma environment.

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.

Performance and Durability of Thin Film Thermocouple Array on a Porous Electrode.

PubMed

Guk, Erdogan; Ranaweera, Manoj; Venkatesan, Vijay; Kim, Jung-Sik

2016-08-23

Management of solid oxide fuel cell (SOFC) thermal gradients is vital to limit thermal expansion mismatch and thermal stress. However, owing to harsh operation conditions of SOFCs and limited available space in stack configuration, the number of techniques available to obtain temperature distribution from the cell surface is limited. The authors previously developed and studied a thermocouple array pattern to detect surface temperature distribution on an SOFC in open circuit conditions. In this study, the performance in terms of mechanical durability and oxidation state of the thin film thermoelements of the thermocouple array on the porous SOFC cathode is investigated. A thin-film multi-junction thermocouple array was sputter deposited using a magnetron sputter coater. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) characterisation techniques were carried out to understand characteristics of the thin film before and after temperature (20 °C-800 °C) measurement. Temperature readings from the sensor agreed well with the closely placed commercial thermocouple during heating segments. However, a sensor failure occurred at around 350 °C during the cooling segment. The SEM and XPS tests revealed cracks on the thin film thermoelements and oxidation to the film thickness direction.

Performance and Durability of Thin Film Thermocouple Array on a Porous Electrode

PubMed Central

Guk, Erdogan; Ranaweera, Manoj; Venkatesan, Vijay; Kim, Jung-Sik

2016-01-01

Management of solid oxide fuel cell (SOFC) thermal gradients is vital to limit thermal expansion mismatch and thermal stress. However, owing to harsh operation conditions of SOFCs and limited available space in stack configuration, the number of techniques available to obtain temperature distribution from the cell surface is limited. The authors previously developed and studied a thermocouple array pattern to detect surface temperature distribution on an SOFC in open circuit conditions. In this study, the performance in terms of mechanical durability and oxidation state of the thin film thermoelements of the thermocouple array on the porous SOFC cathode is investigated. A thin-film multi-junction thermocouple array was sputter deposited using a magnetron sputter coater. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) characterisation techniques were carried out to understand characteristics of the thin film before and after temperature (20 °C–800 °C) measurement. Temperature readings from the sensor agreed well with the closely placed commercial thermocouple during heating segments. However, a sensor failure occurred at around 350 °C during the cooling segment. The SEM and XPS tests revealed cracks on the thin film thermoelements and oxidation to the film thickness direction. PMID:27563893

Cyclic fatigue resistance of ProTaper Universal instruments when subjected to static and dynamic tests.

PubMed

Lopes, Hélio P; Britto, Izabelle M O; Elias, Carlos N; Machado de Oliveira, Julio C; Neves, Mônica A S; Moreira, Edson J L; Siqueira, José F

2010-09-01

This study evaluated the number of cycles to fracture of ProTaper Universal S2 instruments when subjected to static and dynamic cyclic fatigue tests. ProTaper Universal S2 instruments were used until fracture in an artificial curved canal under rotational speed of 300 rpm in either a static or a dynamic test model. Afterward, the length of the fractured segments was measured and fractured surfaces and helical shafts analyzed by scanning electron microscopy (SEM). The number of cycles to fracture was significantly increased when instruments were tested in the dynamic model (P<.001). Instrument separation occurred at the point of maximum flexure within the artificial canals, i.e., the midpoint of the curved canal segment. SEM analysis revealed that fractured surfaces exhibited characteristics of the ductile mode. Plastic deformation was not observed in the helical shaft of fractured instruments. The number of cycles to fracture ProTaper Universal S2 instruments significantly increased with the use of instruments in a dynamic cyclic fatigue test compared with a static model. These findings reinforce the need for performing continuous pecking motions during rotary instrumentation of curved root canals. Copyright (c) 2010 Mosby, Inc. All rights reserved.

Morphology and Growth Kinetics of Straight and Kinked Tin Whiskers

NASA Astrophysics Data System (ADS)

Susan, Donald; Michael, Joseph; Grant, Richard P.; McKenzie, Bonnie; Yelton, W. Graham

2013-03-01

Time-lapse SEM studies of Sn whiskers were conducted to estimate growth kinetics and document whisker morphologies. For straight whiskers, growth rates of 3 to 4 microns per day were measured at room temperature. Two types of kinked whiskers were observed. For Type A kinks, the original growth segment spatial orientation remains unchanged, there are no other changes in morphology or diameter, and growth continues. For Type B kinks, the spatial orientation of the original segment changes and it appears that the whisker bends over. Whiskers with Type B kinks show changes in morphology and diameter at the base, indicating grain boundary motion in the film, which eliminates the conditions suitable for long-term whisker growth. To estimate the errors in the whisker growth measurements, a technique is presented to correct for SEM projection effects. With this technique, the actual growth angles and lengths of a large number of whiskers were collected. It was found that most whiskers grow at moderate or shallow angles with respect to the surface; few straight whiskers grow nearly normal to the surface. In addition, there is no simple correlation between growth angles and lengths for whiskers observed over an approximate 2-year period.

Hybrid overlay metrology for high order correction by using CDSEM

NASA Astrophysics Data System (ADS)

Leray, Philippe; Halder, Sandip; Lorusso, Gian; Baudemprez, Bart; Inoue, Osamu; Okagawa, Yutaka

2016-03-01

Overlay control has become one of the most critical issues for semiconductor manufacturing. Advanced lithographic scanners use high-order corrections or correction per exposure to reduce the residual overlay. It is not enough in traditional feedback of overlay measurement by using ADI wafer because overlay error depends on other process (etching process and film stress, etc.). It needs high accuracy overlay measurement by using AEI wafer. WIS (Wafer Induced Shift) is the main issue for optical overlay, IBO (Image Based Overlay) and DBO (Diffraction Based Overlay). We design dedicated SEM overlay targets for dual damascene process of N10 by i-ArF multi-patterning. The pattern is same as device-pattern locally. Optical overlay tools select segmented pattern to reduce the WIS. However segmentation has limit, especially the via-pattern, for keeping the sensitivity and accuracy. We evaluate difference between the viapattern and relaxed pitch gratings which are similar to optical overlay target at AEI. CDSEM can estimate asymmetry property of target from image of pattern edge. CDSEM can estimate asymmetry property of target from image of pattern edge. We will compare full map of SEM overlay to full map of optical overlay for high order correction ( correctables and residual fingerprints).

Numerical investigations on aerodynamic forces of deformable foils in hovering motions

NASA Astrophysics Data System (ADS)

Su, Xiaohui; Yin, Zhen; Cao, Yuanwei; Zhao, Yong

2017-04-01

In this paper, the aerodynamic forces of deformable foils for hovering flight are numerically investigated by a two-dimensional finite-volume arbitrary Lagrangian Eulerian Navier-Stokes solver. The effects of deformation on the lift force generation mechanisms of deformable wings in hovering flight are studied by comparison and analysis of deformable and rigid wing results. The prescribed deformation of the wings changes their morphing during hovering motion in both camber and angle of incidence. The effects of deflection amplitude, deflection phase, and rotation location on the aerodynamic performances of the foils, as well as the associated flow structures, are investigated in details, respectively. Results obtained show that foil morphing changes both Leading Edge Vortex (LEV) and Trailing Edge Vortex (TEV) generation and development processes. Consequently, the lift force generation mechanisms of deformable wings differ from those of rigid foil models. For the full deformation foil model studied, the effect of foil deformation enhances its lift force during both wake capture and delayed stall. There is an optimized camber amplitude, which was found to be 0.1*chord among those cases simulated. Partial deformation in the foil does not enhance its lift force due to unfavorable foil camber. TEV is significantly changed by the local angle of attack due to the foil deformation. On the other hand, Trailing Edge Flap (TEF) deflection in the hinge connected two-rigid-plate model directly affects the strength of both the LEV and TEV, thus influencing the entire vortex shedding process. It was found that lift enhancement can reach up to 33.5% just by the TEF deflection alone.

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. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Porous carbon-coated graphite electrodes for energy production from salinity gradient using reverse electrodialysis

NASA Astrophysics Data System (ADS)

Lee, Su-Yoon; Jeong, Ye-Jin; Chae, So-Ryong; Yeon, Kyeong-Ho; Lee, Yunkyu; Kim, Chan-Soo; Jeong, Nam-Jo; Park, Jin-Soo

2016-04-01

Performance of graphite foil electrodes coated by porous carbon black (i.e., Vulcan) was investigated in comparison with metal electrodes for reverse electrodialysis (RED) application. The electrode slurry that was used for fabrication of the porous carbon-coated graphite foil is composed of 7.2 wt% of carbon black (Vulcan X-72), 0.8 wt% of a polymer binder (polyvinylidene fluoride, PVdF), and 92.0 wt% of a mixing solvent (dimethylacetamide, DMAc). Cyclic voltammograms of both the porous carbon (i.e., Vulcan)-coated graphite foil electrode and the graphite foil electrode without Vulcan showed good reversibility in the hexacyanoferrate(III) (i.e., Fe(CN)63-) and hexacyanoferrate(II) (i.e., Fe(CN)64-) redox couple and 1 M Na2SO4 at room temperature. However, anodic and cathodic current of the Vulcan-coated graphite foil electrode was much higher than those of the graphite foil electrode. Using a bench-scale RED stack, the current-voltage polarization curve of the Vulcan-coated graphite electrode was compared to that of metal electrodes such as iridium (Ir) and platinum (Pt). From the results, it was confirmed that resistance of four different electrodes increased with the following order: the Vulcan-coated graphite foil

Electron Microscope Studies of Cadmium Mercury Telluride

NASA Astrophysics Data System (ADS)

Lyster, Martin

Available from UMI in association with The British Library. Requires signed TDF. Epitaxial layers of Cd_{x }Hg_{(1-x)}Te grown on various substrates by liquid phase epitaxy and metallo-organic vapour phase epitaxy have been studied using transmission and scanning electron microscopy, in a variety of contrast modes. Wavelength-dispersive X-ray microanalysis has been used to study interfaces in epitaxial specimens, and the results are used to derive diffusion coefficients for a range of values of x in Cd_ {x}Hg_{(1-x)} Te. Extensive use has been made of back-scattered electron contrast in the SEM as a means of compositional mapping, and defect structures are imaged by this technique. The back-scattered electron contrast at interfaces has been studied in detail and is modelled using the Monte Carlo approach. The modelling is combined with calculations and practical measurements of the probe size in the SEM instrument used in the work, to arrive at a quantitative explanation of this contrast. The SEM and scintillator detector used allow a spatial resolution of better than 1000A, but it is shown that improvements in this are possible with present technology. Scanning infra-red microscopy (SIRM) and high -resolution transmission electron microscopy (HREM) have been applied to the study of CdTe. SIRM images reveal information about Te precipitation, including particle size and density. HREM images provide results concerning dislocation structures in CdTe. Selected-area diffraction contrast TEM results are presented which illustrate the microstructure of LPE and MOVPE material; and TEM foil preparation techniques are discussed, including the choice of ion species for milling cross-sectional specimens. In view of the results obtained, suggestions are made for future work in this field.

Origin of high Coulombic loss during sodiation in Na-Sn battery

NASA Astrophysics Data System (ADS)

Byeon, Young-Woon; Choi, Yong-Seok; Ahn, Jae-Pyoung; Lee, Jae-Chul

2017-03-01

Electrochemical sodiation is performed in crystalline Sn foil using in situ scanning electron microscopy (SEM) to simultaneously measure the changes in the electrical resistivity and volume of the Sn anode in a Na-Sn battery. We observe that sodiation causes an increase in the Sn anode resistivity by six orders of magnitude. Ab initio molecular dynamics simulations of the Na-Sn alloy system demonstrate that the increased resistivity of the anode is caused by the formation of an electrically resistive amorphous NaSn phase (a-NaSn) with a pseudogap. It is also observed that the formation of a-NaSn is always accompanied by a large volume expansion of ∼200%, causing the development of residual tensile stress. The residual stress in turn alters the electronic structure of the a-NaSn phase, further increasing the resistivity of a-NaSn and thus decreasing the energy efficiency of the Na-Sn battery.

Patterning of Thick Parylene Films by Oxygen Plasma for Application as Exploding Foil Initiator Flyer Material

DTIC Science & Technology

2009-09-01

exploding foil initiator ( EFI ) type fuzes are being explored to...Acronyms Au gold Cr chromium Cu copper EFI exploding foil initiator BOE buffered oxide etch MEMS microelectromechanical systems RIE reactive ion...Patterning of Thick Parylene Films by Oxygen Plasma for Application as Exploding Foil Initiator Flyer Material by Eugene Zakar and Michael

Influence of micromachined targets on laser accelerated proton beam profiles

NASA Astrophysics Data System (ADS)

Dalui, Malay; Permogorov, Alexander; Pahl, Hannes; Persson, Anders; Wahlström, Claes-Göran

2018-03-01

High intensity laser-driven proton acceleration from micromachined targets is studied experimentally in the target-normal-sheath-acceleration regime. Conical pits are created on the front surface of flat aluminium foils of initial thickness 12.5 and 3 μm using series of low energy pulses (0.5-2.5 μJ). Proton acceleration from such micromachined targets is compared with flat foils of equivalent thickness at a laser intensity of 7 × 1019 W cm-2. The maximum proton energy obtained from targets machined from 12.5 μm thick foils is found to be slightly lower than that of flat foils of equivalent remaining thickness, and the angular divergence of the proton beam is observed to increase as the depth of the pit approaches the foil thickness. Targets machined from 3 μm thick foils, on the other hand, show evidence of increasing the maximum proton energy when the depths of the structures are small. Furthermore, shallow pits on 3 μm thick foils are found to be efficient in reducing the proton beam divergence by a factor of up to three compared to that obtained from flat foils, while maintaining the maximum proton energy.

Approximating the near-edge mass absorption coefficients for Ni using an ultra-thin bimetal foil

DOE PAGES

Alkire, Randall W.

2016-11-01

In an effort to improve the characteristics of a fluorescing metal-foil-based beam position monitor, a new bimetal ultra-thin (0.98/0.67 µm) Ti–Ni foil was introduced to replace an existing single-element ultra-thin 0.5 µm thick Cr foil. During characterization it was determined that absorption measurements on the bimetal foil could be used to fit the Ni mass absorption coefficients accurately in the vicinity of the NiKedge. Comparison with experimental results from the literature demonstrated that the fitting procedure produced coefficients with uncertainties of the order of ±1%. Once determined, these fit coefficients allowed the thickness of an independently mounted 8 µm thickmore » Ni foil to be computed from absorption measurements instead of relying on a tool-based measurement of the foil thickness. Using the 8 µm thick foil, a continuous map of Ni mass absorption coefficients was produced at 1 eV resolution throughout the near-edge region. Lastly, this high-resolution map marks a significant improvement over the existing NIST XCOM or FFAST database mass absorption coefficients, which have estimated errors of 10–20% for the near-edge region.« less

Epitaxial lift-off of electrodeposited single-crystal gold foils for flexible electronics

NASA Astrophysics Data System (ADS)

Mahenderkar, Naveen K.; Chen, Qingzhi; Liu, Ying-Chau; Duchild, Alexander R.; Hofheins, Seth; Chason, Eric; Switzer, Jay A.

2017-03-01

We introduce a simple and inexpensive procedure for epitaxial lift-off of wafer-size flexible and transparent foils of single-crystal gold using silicon as a template. Lateral electrochemical undergrowth of a sacrificial SiOx layer was achieved by photoelectrochemically oxidizing silicon under light irradiation. A 28-nanometer-thick gold foil with a sheet resistance of 7 ohms per square showed only a 4% increase in resistance after 4000 bending cycles. A flexible organic light-emitting diode based on tris(bipyridyl)ruthenium(II) that was spin-coated on a foil exploited the transmittance and flexibility of the gold foil. Cuprous oxide as an inorganic semiconductor that was epitaxially electrodeposited onto the gold foils exhibited a diode quality factor n of 1.6 (where n = 1.0 for an ideal diode), compared with a value of 3.1 for a polycrystalline deposit. Zinc oxide nanowires electrodeposited epitaxially on a gold foil also showed flexibility, with the nanowires intact up to 500 bending cycles.

Improvement of Surface Layer Characteristics by Shot Lining

NASA Astrophysics Data System (ADS)

Harada, Yasunori

In the present study, lining of the metal with foils using shot peening was investigated to improve the surface layer characteristics. In the shot peening experiment, the foils set on the metal are pelted with hard particles traveling at a high velocity. The foils are bonded to the metal surface due to plastic deformation induced by the collision of the particles. The foils and the metal are heated to heighten the bondability because of the reduction of flow stress. Lining the metal with the hard powder sandwiched between two aluminum foil sheets was also attempted. In this experiment, a centrifugal shot peening machine wite an electrical heater was employed. The metals are commercially aluminium alloys and magnesium alloys, and the foils are commercially aluminum, titanium and nickel. The effects of shot speed and the heating temperature on the bondability were examined. Wear resistance was also evaluated by grinding. The foils were successfully bonded to the metal surface. It was found that the present method is effective in improving of surface layer characteristics.

A suspended boron foil multi-wire proportional counter neutron detector

NASA Astrophysics Data System (ADS)

Nelson, Kyle A.; Edwards, Nathaniel S.; Hinson, Niklas J.; Wayant, Clayton D.; McGregor, Douglas S.

2014-12-01

Three natural boron foils, approximately 1.0 cm in diameter and 1.0 μm thick, were obtained from The Lebow Company and suspended in a multi-wire proportional counter. Suspending the B foils allowed the alpha particle and Li ion reaction products to escape simultaneously, one on each side of the foil, and be measured concurrently in the gas volume. The thermal neutron response pulse-height spectrum was obtained and two obvious peaks appear from the 94% and 6% branches of the 10B(n,α)7Li neutron reaction. Scanning electron microscope images were collected to obtain the exact B foil thicknesses and MCNP6 simulations were completed for those same B thicknesses. Pulse-height spectra obtained from the simulations were compared to experimental data and matched well. The theoretical intrinsic thermal-neutron detection efficiency for enriched 10B foils was calculated and is presented. Additionally, the intrinsic thermal neutron detection efficiency of the three natural B foils was calculated to be 3.2±0.2%.

Angular distributions of reflected and refracted relativistic electron beams crossing a thin planar target at a small angle to its surface

DOE Office of Scientific and Technical Information (OSTI.GOV)

Serov, A. V., E-mail: serov@x4u.lebedev.ru; Mamonov, I. A.; Kol’tsov, A. V., E-mail: koltsov@x4u.lebedev.ru

2015-10-15

The scattering of electrons by aluminum, copper, and lead foils, as well as by bimetallic aluminum-lead and aluminum-copper foils, has been studied experimentally. A microtron with an energy of particles of 7.4 MeV has been used as a source of electrons. The beam of particles incident on a target at small angles is split into particles reflected from the foil, which constitute a reflected beam, and particles crossing the foil, which constitute a refracted beam. The effect of the material and thickness of the foil, as well as the angle between the initial trajectory of the beam and the planemore » of the target, on the direction of motion and the angular divergence of the beam crossing the foil and the beam reflected from the foil has been analyzed. Furthermore, the effect of the sequence of metal layers in bimetallic films on the angles of refraction and reflection of the beam has been examined.« less

Collisions of plastic and foam laser-driven foils studied by orthogonal x-ray imaging.

NASA Astrophysics Data System (ADS)

Aglitskiy, Y.; Metzler, N.; Karasik, M.; Serlin, V.; Obenschain, S. P.; Schmitt, A. J.; Velikovich, A. L.; Zalesak, S. T.; Gardner, J. H.; Weaver, J.; Oh, J.; Harding, E. C.

2007-11-01

We report an experimental study of hydrodynamic Rayleigh-Taylor and Richtmyer-Meshkov-type instabilities developing at the material interface produced in double-foil collisions. Our double-foil targets consist of a plastic foil irradiated by the 4 ns Nike KrF laser pulse at ˜50 TW/cm^2 and accelerated toward a stationary plastic or foam foil. Either the rear side of the front foil or the front side of the rear foil is rippled. Orthogonal imaging, i. e., a simultaneous side-on and face-on x-ray radiography of the targets has been used in these experiments to observe the process of collision and the evolution of the areal mass amplitude modulation. Its observed evolution is similar to the case of the classical RM instability in finite thickness targets first studied by Y. Aglitsky et al., Phys. Plasmas 13, 80703 (2006). Our data are favorably compared with 1D and 2D simulation results.

First experience with carbon stripping foils for the 160 MeV H- injection into the CERN PSB

NASA Astrophysics Data System (ADS)

Weterings, Wim; Bracco, Chiara; Jorat, Louise; Noulibos, Remy; van Trappen, Pieter

2018-05-01

160 MeV H- beam will be delivered from the new CERN linear accelerator (Linac4) to the Proton Synchrotron Booster (PSB), using a H- charge-exchange injection system. A 200 µg/cm2 carbon stripping foil will convert H- into protons by stripping off the electrons. The H- charge-exchange injection principle will be used for the first time in the CERN accelerator complex and involves many challenges. In order to gain experience with the foil changing mechanism and the very fragile foils, in 2016, prior to the installation in the PSB, a stripping foil test stand has been installed in the Linac4 transfer line. In addition, parts of the future PSB injection equipment are also temporarily installed in the Linac4 transfer line for tests with a 160 MeV H- commissioning proton beam. This paper describes the foil changing mechanism and control system, summarizes the practical experience of gluing and handling these foils and reports on the first results with beam.

The effect of polyether functional polydimethylsiloxane on surface and thermal properties of waterborne polyurethane

NASA Astrophysics Data System (ADS)

Zheng, Guikai; Lu, Ming; Rui, Xiaoping

2017-03-01

Waterborne polyurethanes (WPU) modified with polyether functional polydimethylsiloxane (PDMS) were synthesized by pre-polymerization method using isophorone diisocyanate (IPDI) and 1,4-butanediol (BDO) as hard segments and polybutylene adipate glycol (PBA) and polyether functional PDMS as soft segments. The effect of polyether functional PDMS on phase separation, thermal properties, surface properties including surface composition, morphology and wettability were investigated by FTIR, contact angle measurements, ARXPS, SEM-EDS, AFM, TG and DSC. The results showed that the compatibility between urethane hard segment and PDMS modified with polyether was good, and there was no distinct phase separation in both bulk and surface of WPU films. The degradation temperature and low temperature flexibility increased with increasing amounts of polyether functional PDMS. The enrichment of polyether functional PDMS with low surface energy on the surface imparted excellent hydrophobicity to WPU films.

Development of thick, long-lived carbon stripper foils for PSR of LANL

NASA Astrophysics Data System (ADS)

Sugai, I.; Oyaizu, M.; Kawakami, H.; Ohmori, C.; Hattori, T.; Kawasaki, K.; Borden, M. J.; Macek, R. J.

1995-02-01

Thick carbon stripper foils (multi-layer thickness ≈ 200 μg/cm 2) have been developed for use with 800 MeV, H + ion beam in the Proton Storage Ring (PSR) at Los Alamos National Laboratory. Foils were prepared by means of the modified controlled ACDC arc discharge method (mCADAD). The lifetime measurements of the foils made by different methods were performed using an 800 MeV proton beam of up to 85 μA in the PSR, and a 3.2 MeV Ne + ion beam of 3 μA at Tokyo Institute of Technology. The foils made by the mCADAD method showed very long lifetimes, as compared to other foils tested, for both 800 MeV p and 3.2 MeV Ne + beam bombardments.

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.

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 this case, the load capacity is constant and in fact often decreases with speed if other factors such as thermal conditions and runner distortions are permitted to dominate the bearing performance.

Calibration of a thin metal foil for infrared imaging video bolometer to estimate the spatial variation of thermal diffusivity using a photo-thermal technique.

PubMed

Pandya, Shwetang N; Peterson, Byron J; Sano, Ryuichi; Mukai, Kiyofumi; Drapiko, Evgeny A; Alekseyev, Andrey G; Akiyama, Tsuyoshi; Itomi, Muneji; Watanabe, Takashi

2014-05-01

A thin metal foil is used as a broad band radiation absorber for the InfraRed imaging Video Bolometer (IRVB), which is a vital diagnostic for studying three-dimensional radiation structures from high temperature plasmas in the Large Helical Device. The two-dimensional (2D) heat diffusion equation of the foil needs to be solved numerically to estimate the radiation falling on the foil through a pinhole geometry. The thermal, physical, and optical properties of the metal foil are among the inputs to the code besides the spatiotemporal variation of temperature, for reliable estimation of the exhaust power from the plasma illuminating the foil. The foil being very thin and of considerable size, non-uniformities in these properties need to be determined by suitable calibration procedures. The graphite spray used for increasing the surface emissivity also contributes to a change in the thermal properties. This paper discusses the application of the thermographic technique for determining the spatial variation of the effective in-plane thermal diffusivity of the thin metal foil and graphite composite. The paper also discusses the advantages of this technique in the light of limitations and drawbacks presented by other calibration techniques being practiced currently. The technique is initially applied to a material of known thickness and thermal properties for validation and finally to thin foils of gold and platinum both with two different thicknesses. It is observed that the effect of the graphite layer on the estimation of the thermal diffusivity becomes more pronounced for thinner foils and the measured values are approximately 2.5-3 times lower than the literature values. It is also observed that the percentage reduction in thermal diffusivity due to the coating is lower for high thermal diffusivity materials such as gold. This fact may also explain, albeit partially, the higher sensitivity of the platinum foil as compared to gold.

Calibration of a thin metal foil for infrared imaging video bolometer to estimate the spatial variation of thermal diffusivity using a photo-thermal technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pandya, Shwetang N., E-mail: pandya.shwetang@LHD.nifs.ac.jp; Sano, Ryuichi; Peterson, Byron J.

A thin metal foil is used as a broad band radiation absorber for the InfraRed imaging Video Bolometer (IRVB), which is a vital diagnostic for studying three-dimensional radiation structures from high temperature plasmas in the Large Helical Device. The two-dimensional (2D) heat diffusion equation of the foil needs to be solved numerically to estimate the radiation falling on the foil through a pinhole geometry. The thermal, physical, and optical properties of the metal foil are among the inputs to the code besides the spatiotemporal variation of temperature, for reliable estimation of the exhaust power from the plasma illuminating the foil.more » The foil being very thin and of considerable size, non-uniformities in these properties need to be determined by suitable calibration procedures. The graphite spray used for increasing the surface emissivity also contributes to a change in the thermal properties. This paper discusses the application of the thermographic technique for determining the spatial variation of the effective in-plane thermal diffusivity of the thin metal foil and graphite composite. The paper also discusses the advantages of this technique in the light of limitations and drawbacks presented by other calibration techniques being practiced currently. The technique is initially applied to a material of known thickness and thermal properties for validation and finally to thin foils of gold and platinum both with two different thicknesses. It is observed that the effect of the graphite layer on the estimation of the thermal diffusivity becomes more pronounced for thinner foils and the measured values are approximately 2.5–3 times lower than the literature values. It is also observed that the percentage reduction in thermal diffusivity due to the coating is lower for high thermal diffusivity materials such as gold. This fact may also explain, albeit partially, the higher sensitivity of the platinum foil as compared to gold.« less

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.

Applying a foil queue micro-electrode in micro-EDM to fabricate a 3D micro-structure

NASA Astrophysics Data System (ADS)

Xu, Bin; Guo, Kang; Wu, Xiao-yu; Lei, Jian-guo; Liang, Xiong; Guo, Deng-ji; Ma, Jiang; Cheng, Rong

2018-05-01

Applying a 3D micro-electrode in a micro electrical discharge machining (micro-EDM) can fabricate a 3D micro-structure with an up and down reciprocating method. However, this processing method has some shortcomings, such as a low success rate and a complex process for fabrication of 3D micro-electrodes. By focusing on these shortcomings, this paper proposed a novel 3D micro-EDM process based on the foil queue micro-electrode. Firstly, a 3D micro-electrode was discretized into several foil micro-electrodes and these foil micro-electrodes constituted a foil queue micro-electrode. Then, based on the planned process path, foil micro-electrodes were applied in micro-EDM sequentially and the micro-EDM results of each foil micro-electrode were able to superimpose the 3D micro-structure. However, the step effect will occur on the 3D micro-structure surface, which has an adverse effect on the 3D micro-structure. To tackle this problem, this paper proposes to reduce this adverse effect by rounded corner wear at the end of the foil micro-electrode and studies the impact of machining parameters on rounded corner wear and the step effect on the micro-structure surface. Finally, using a wire cutting voltage of 80 V, a current of 0.5 A and a pulse width modulation ratio of 1:4, the foil queue micro-electrode was fabricated by wire electrical discharge machining. Also, using a pulse width of 100 ns, a pulse interval of 200 ns, a voltage of 100 V and workpiece material of 304# stainless steel, the foil queue micro-electrode was applied in micro-EDM for processing of a 3D micro-structure with hemispherical features, which verified the feasibility of this process.

Simulation of turn-by-turn passage of protons through the H-minus stripping foil in booster

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gardner, C.

Equations for transverse emittance growth due to multiple passes of circulating proton beam through the H-minus stripping foil in Booster were developed in [1]. These were based on simple principles of statistics and simple assumptions about the initial distribution of particles incident on the foil. It was assumed there that the foil dimensions and position of the incoming beam are such that all particles hit the foil on every turn around the machine. In the present note we assume only that all incoming H-minus ions from Linac hit the foil and are stripped of their electrons. The resulting protons circulatemore » indefinitely around the machine. Setups in which the foil width is reduced so that not all protons hit the foil on every turn are studied here by simulation. The aim is to determine the effectiveness of such setups in reducing the emittance growth of circulating proton beam during the injection of H-minus beam. The simulations also serve as a check of the equations developed in [1], and vice versa. The particulars of the simulation setup are given in Sections 1 through 11. Figures 1 through 12 show simulation results for the case in which all particles hit the foil on every turn. The results are in good agreement with those obtained from the equations of reference [1]. Figures 13 through 19 show simulation results for various setups in which the foil width is reduced. These results are summarized in Section 12. In all gures the horizontal axis gives the turn number. The unit of the vertical axis is micrometers ( m) in all plots of emittance.« less

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.

Influence of UV and Gamma radiations on the induced birefringence of stretched poly(vinyl) alcohol foils

NASA Astrophysics Data System (ADS)

Nechifor, Cristina-Delia; Zelinschi, Carmen Beatrice; Dorohoi, Dana-Ortansa

2014-03-01

The aim of our paper is to evidence the influence of Gamma and UV radiations on the induced birefringence of poly(vinyl alcohol) stretched foils. Thin foils of PVA were prepared and dried without modifying their surfaces. The polymeric foils were irradiated from 15 min to 6 h using UV and Gamma radiations. The induced by stretching under heating birefringence of PVA films was measured at λ = 589.3 nm with a Babinet Compensator. Physico-chemical processes (photo stabilization, photo degradation, oxidation) induced by irradiation of polymer matrix influence both the stretching degree and the anisotropy of etired foils. An increase of birefringence versus the stretching ratio of the PVA foils was evidenced for all studied samples. The dependence of the birefringence on the exposure time, stretching ratio and nature of radiation was also confirmed.

Modification of Bushing Test Rig and Research of Variable Inlet Guide Vane Bushings For Further Development of PM304 Bushings

NASA Technical Reports Server (NTRS)

Yanke, Anne

2004-01-01

PS304 is a high temperature solid lubricant coating comprised of a nickel-chrome binder, chrome oxide hardener, barium-calcium fluoride high temperature lubricant, and silver as the low temperature lubricant. This coating is used to lubricate Oil-Free Foil Air Bearings as they experience friction and wear during start up and shut down. The coating deposition process begins with undercutting the shaft. This area is then sandblasted to provide a rough surface for the coating to adhere to. The coating powder is then sent through the plasma spray gun and a reasonably thick layer is applied to the undercut area of the shaft. The coating is then ground down even with the surface of the shaft and gets a nice polished finish. The foil air bearings use the solid lubricant, as mentioned above, during start up and shut down. During normal operating conditions, generally above 2000RPM, the bearings utilize air as their lubricant. Foil air bearings are comprised of a thin top foil and a corrugated bump foil. They have an interference fit with the shaft before operation. As the air gets "trapped" between the top foil and the shaft, it presses the top foil against the bump foil, in turn compressing the bumps. As the bumps compress, it allows for the air to separate the top foil from the shaft, therefore, utilizing the trapped air as its lubricant.

Developing NanoFoil-Heated Thin-Film Thermal Battery

DTIC Science & Technology

2013-09-01

buffer discs (in gray) sandwiching the NanoFoil disc (in yellow). Two Microtherm discs (in dark gray) bracketed the sandwich to prevent excessive heat...of the fuse strip with a Microtherm disc. Cathode Electrolyte Anode Microtherm Heat paper NanoFoil Buffer Agilent 34970A 606.5 Nichrome wire Maccor...gray) sandwiching the NanoFoil disc (in yellow). Two Microtherm discs (in dark gray) bracketed the sandwich to prevent excessive heat loss

A deformation mechanism of hard metal surrounded by soft metal during roll forming

PubMed Central

YU, Hailiang; TIEU, A. Kiet; LU, Cheng; LIU, Xiong; GODBOLE, Ajit; LI, Huijun; KONG, Charlie; QIN, Qinghua

2014-01-01

It is interesting to imagine what would happen when a mixture of soft-boiled eggs and stones is deformed together. A foil made of pure Ti is stronger than that made of Cu. When a composite Cu/Ti foil deforms, the harder Ti will penetrate into the softer Cu in the convex shapes according to previously reported results. In this paper, we describe the fabrication of multilayer Cu/Ti foils by the roll bonding technique and report our observations. The experimental results lead us to propose a new deformation mechanism for a hard metal surrounded by a soft metal during rolling of a laminated foil, particularly when the thickness of hard metal foil (Ti, 25 μm) is much less than that of the soft metal foil (Cu, 300 μm). Transmission Electron Microscope (TEM) imaging results show that the hard metal penetrates into the soft metal in the form of concave protrusions. Finite element simulations of the rolling process of a Cu/Ti/Cu composite foil are described. Finally, we focus on an analysis of the deformation mechanism of Ti foils and its effects on grain refinement, and propose a grain refinement mechanism from the inside to the outside of the laminates during rolling. PMID:24853192

3D reconstruction of synapses with deep learning based on EM Images

NASA Astrophysics Data System (ADS)

Xiao, Chi; Rao, Qiang; Zhang, Dandan; Chen, Xi; Han, Hua; Xie, Qiwei

2017-03-01

Recently, due to the rapid development of electron microscope (EM) with its high resolution, stacks delivered by EM can be used to analyze a variety of components that are critical to understand brain function. Since synaptic study is essential in neurobiology and can be analyzed by EM stacks, the automated routines for reconstruction of synapses based on EM Images can become a very useful tool for analyzing large volumes of brain tissue and providing the ability to understand the mechanism of brain. In this article, we propose a novel automated method to realize 3D reconstruction of synapses for Automated Tapecollecting Ultra Microtome Scanning Electron Microscopy (ATUM-SEM) with deep learning. Being different from other reconstruction algorithms, which employ classifier to segment synaptic clefts directly. We utilize deep learning method and segmentation algorithm to obtain synaptic clefts as well as promote the accuracy of reconstruction. The proposed method contains five parts: (1) using modified Moving Least Square (MLS) deformation algorithm and Scale Invariant Feature Transform (SIFT) features to register adjacent sections, (2) adopting Faster Region Convolutional Neural Networks (Faster R-CNN) algorithm to detect synapses, (3) utilizing screening method which takes context cues of synapses into consideration to reduce the false positive rate, (4) combining a practical morphology algorithm with a suitable fitting function to segment synaptic clefts and optimize the shape of them, (5) applying the plugin in FIJI to show the final 3D visualization of synapses. Experimental results on ATUM-SEM images demonstrate the effectiveness of our proposed method.

Metal foil method for noncontact measurement of lateral vibrations of a nonmetallic cylinder by a solenoid

NASA Astrophysics Data System (ADS)

Han, Soon Woo; Bang, Young Bong; Kim, Yoon Young

2006-10-01

This investigation shows that if a solenoid encircles a metal foil loop wound around a nonmetallic cylinder vibrating laterally, an electromotive force is induced in the solenoid. The induction is possible only when the foil loop is complete and an antisymmetric magnetic field is applied to the foil. In this work, stationary permanent magnets were used. Because the solenoid is the sensing element, no physical contact between the element and a test specimen is required. The effects of the metal foil thickness and width on the measurement sensitivity were studied and vibration modal testing of an acryl cylinder was performed.

Novel technique of making thin target foil of high density material via rolling method

NASA Astrophysics Data System (ADS)

Gupta, C. K.; Rohilla, Aman; Singh, R. P.; Singh, Gurjot; Chamoli, S. K.

2018-05-01

The conventional rolling method fails to yield good quality thin foils of thicknesses less than 2 mg/cm2 for high density materials with Z ≥ 70 (e.g. gold, lead). A special and improved technique has been developed to obtain such low thickness good quality gold foils by rolling method. Using this technique thin gold foils of thickness in the range of 0.850-2.5 mg/cm2 were obtained in the present work. By making use of alcohol during rolling, foils of thickness 1 mg/cm2 can be obtained in shorter time with less effort.

TiO{sub 2} flower-like nanostructures decorated with CdS/PbS nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Trenczek-Zajac, Anita, E-mail: anita.trenczek-zajac@agh.edu.pl; Kusior, Anna; Lacz, Agnieszka

Highlights: • TiO{sub 2} flower-like nanostructures were prepared with the use of Ti foil and 30% H{sub 2}O{sub 2}. • QDs of CdS and PbS were deposited using the SILAR method. • The SILAR method makes it possible to control the size of QDs. • Band gap energy of CdS was found to be 2.35 eV. • Sensitization of TiO{sub 2} with CdS or PbS improves the photoelectrochemical properties. - Abstract: Flower-like nanostructures of TiO{sub 2} were prepared by immersing Ti foil in 30% H{sub 2}O{sub 2} at 80 °C for times varying from 15 to 240 min. Upon annealingmore » at 450 °C in an Ar atmosphere, the received amorphous samples crystallized in an anatase structure with rutile as a minority phase. SEM images revealed that partially formed flowers were present at the surface of the prepared samples as early as after 15 min of immersion. The size of the individual flowers increased from 400–800 nm after 15 min of reaction to 2.5–6.0 μm after 240 min. It was also found that surface is very rough and surface development is considerable. After 45 min of immersion, the nanoflowers were sensitized with CdS and PbS quantum dots (QDs-CdS/QDs-PbS) deposited using the SILAR method from water- and methanol-based precursor solutions at different concentrations (0.001–0.1 M). QDs-CdS crystallized in the hawleyite structure, while QDs-PbS in the galena form. SEM analysis showed the tendency of quantum dots to agglomerate at high concentrations of the precursor in water-based solutions. QDs obtained from methanol-based solutions were uniformly distributed. The produced QDs-PbS were smaller than QDs-CdS. Based on the optical reflectance spectra, the band-gap energies of TiO{sub 2} nanostructures with and without QDs were calculated to be 3.32 eV for flower-like TiO{sub 2} nanostructures and 2.35 eV for QDs-CdS. The photoelectrochemical behaviour of nanoflowers was found to improve significantly after the deposition of QDs-CdS.« less

Pulsed-Plasma Physical Vapor Deposition Approach Toward the Facile Synthesis of Multilayer and Monolayer Graphene for Anticoagulation Applications.

PubMed

Vijayaraghavan, Rajani K; Gaman, Cezar; Jose, Bincy; McCoy, Anthony P; Cafolla, Tony; McNally, Patrick J; Daniels, Stephen

2016-02-01

We demonstrate the growth of multilayer and single-layer graphene on copper foil using bipolar pulsed direct current (DC) magnetron sputtering of a graphite target in pure argon atmosphere. Single-layer graphene (SG) and few-layer graphene (FLG) films are deposited at temperatures ranging from 700 °C to 920 °C within <30 min. We find that the deposition and post-deposition annealing temperatures influence the layer thickness and quality of the graphene films formed. The films were characterized using atomic force microscopy (AFM), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and optical transmission spectroscopy techniques. Based on the above studies, a diffusion-controlled mechanism was proposed for the graphene growth. A single-step whole blood assay was used to investigate the anticoagulant activity of graphene surfaces. Platelet adhesion, activation, and morphological changes on the graphene/glass surfaces, compared to bare glass, were analyzed using fluorescence microscopy and SEM techniques. We have found significant suppression of the platelet adhesion, activation, and aggregation on the graphene-covered surfaces, compared to the bare glass, indicating the anticoagulant activity of the deposited graphene films. Our production technique represents an industrially relevant method for the growth of SG and FLG for various applications including the biomedical field.

Substrate bias induced synthesis of flowered-like bunched carbon nanotube directly on bulk nickel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bisht, Atul; Academy of Scientific and Innovative Research; Chockalingam, S.

2016-02-15

Highlights: • Flowered-like bunched MWCNTs have been synthesized by MW PECVD technique. • Effect of substrate bias on the properties of MWCNT has been studied. • Minimum E{sub T} = 1.9 V/μm with β = 4770 has been obtained in the film deposited at −350 V. - Abstract: This paper reports the effect of substrate bias on the multiwalled carbon nanotube (MWCNT) deposited on nickel foil by microwave plasma enhanced chemical vapor deposition technique. The MWCNTs have been characterized by the scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), Raman spectroscopy, field emission and current–voltage characteristic of themore » heterojunction diode. The SEM images exhibit unique hierarchical flowered-like bunched and conformally coated MWCNTs. Substrate bias induced ion bombardment helps in the enhancement of hydrocarbon dissociation and is responsible for flowered-like MWCNTs growth. The HRTEM micrographs show the base growth mechanism for MWCNTs. The value of turn on field for emission decreases from 5.5 to 1.9 V/μm and field enhancement factor increases from 927 to 4770, respectively, with the increase of substrate bias. The diode ideality factor of CNT/ n-Si heterojunction is evaluated as 2.4 and the on/off current ratio is found to be 7 at ±2 V, respectively.« less

F-doped VO2 nanoparticles for thermochromic energy-saving foils with modified color and enhanced solar-heat shielding ability.

PubMed

Dai, Lei; Chen, Shi; Liu, Jianjun; Gao, Yanfeng; Zhou, Jiadong; Chen, Zhang; Cao, Chuanxiang; Luo, Hongjie; Kanehira, Minoru

2013-07-28

F-doped VO2 (M1) nanoparticles were prepared via one-pot hydrothermal synthesis. The F-doping can minimise the size of the VO2 (M1) nanoparticles, induce a homogeneous size distribution and effectively decrease the phase transition temperature to 35 °C at 2.93% F in VO2. VO2 smart glass foils obtained by casting these nanoparticles exhibit excellent thermochromism in the near-infrared region, which suggests that these foils can be used for energy-efficient glass. Compared to a pure VO2 foil, the 2.93% F-doped VO2 foil exhibits an increased solar-heat shielding ability (35.1%) and a modified comfortable colour, while still retaining an excellent solar modulation ability (10.7%) and an appropriate visible transmittance (48.7%). The F-doped VO2 foils are the first to simultaneously meet the requirements of a reduced phase transition temperature, diluted colour and excellent thermochromic properties, and these properties make the further improved F-doped VO2 foils suitable for commercial applications in energy efficient glass.

Coherent synchrotron emission in transmission with double foil target

NASA Astrophysics Data System (ADS)

Xu, X. R.; Qiao, B.; Chang, H. X.; Zhang, Y. X.; Zhang, H.; Zhong, C. L.; Zhou, C. T.; Zhu, S. P.; He, X. T.

2018-04-01

Generation of intense single attosecond pulses from coherent synchrotron emission (CSE), in the transmitted direction of the laser-irradiated double foil targets, has been investigated theoretically and numerically. Unlike conventional CSE in the single foil target case, here the dense electron nanobunch is formed in the vacuum gap between two foils, which is composed of the electrons blown out from the first ultrathin foil. Owing to the existence of the vacuum gap, the electron nanobunch can be accelerated to more energy. In addition, more laser energy can penetrate through the nanobunch and get reflected from the second foil. These reflected lasers and electron nanobunches interact with each other and results in enhanced CSE and consequently, the generation of intense attosecond pulses. Particle-in-cell simulations show that a single attosecond pulse with duration of 18 {as}, photon energy > 0.16 {keV} and peak intensity of 1.7× {10}20 {{W}}/{cm}}2 can be obtained from the double-foil targets irradiated by a laser at intensity of 7.7× {10}21 {{W}}/{cm}}2.

Nonlinear dynamic analysis of rigid rotor supported by gas foil bearings: Effects of gas film and foil structure on subsynchronous vibrations

NASA Astrophysics Data System (ADS)

Guo, Zhiyang; Feng, Kai; Liu, Tianyu; Lyu, Peng; Zhang, Tao

2018-07-01

Highly nonlinear subsynchronous vibrations are the main causing factors of failure in gas foil bearing (GFB)-rotor systems. Thus, investigating the vibration generation mechanisms and the relationship between subsynchronous vibrations and GFBs is necessary to ensure the healthy operation of rotor systems. In this study, an integrated nonlinear dynamic model with the consideration of shaft motion, unsteady gas film, and deformations of foil structure is established to investigate the effect of gas film and foil structure on system subsynchronous response. One test rig of GFB-rotor system is developed for model comparison. High agreement is shown between the prediction and test data, especially in the frequency domain. The nonlinear dynamic response is analyzed using waterfall plots, operation deflection shapes, journal orbits, Poincaré maps, and fast Fourier transforms. The parameter studies reveal that subsynchronous vibrations are highly related to gas film and foil structure. Subsynchronous vibrations can be adjusted by parameters such as bump stiffness, nominal clearance, and static loads. Therefore, gas foil bearing parameters should be carefully adjusted by system manufacturers to achieve the best rotordynamic performance.

Hypervelocity impact microfoil perforations in the LEO space environment (LDEF, MAP AO-023 experiment)

NASA Technical Reports Server (NTRS)

Mcdonnell, J. A. M.; Stevenson, T. J.

1992-01-01

The Microabrasion Foil Experiment comprises arrays of frames, each supporting two layers of closely spaced metallic foils and a back-stop plate. The arrays, deploying aluminum and brass foil ranging from 1.5 to some 30 microns were exposed for 5.78 years on NASA's LDEF at a mean altitude of 458 km. They were deployed on the North, South, East, West, and Space pointing faces; results presented comprise the perforation rates for each location as a function of foil thickness. Initial results refer primarily to aluminum of 5 microns thickness or greater. This penetration distribution, comprising 2,342 perforations in total, shows significantly differing characteristics for each detector face. The anisotropy confirms, incorporating the dynamics of particulate orbital mechanics, the dominance of incorporating extraterrestrial particulates penetrating thicknesses greater than 20 microns in Al foil, yielding fluxes compatible with hyperbolic geocentric velocities. For thinner foils, a disproportionate increase in flux of particles on the East, North, and South faces shows the presence of orbital particulates which exceed the extraterrestrial component perforation rate at 5 micron foil thickness by a factor of approx. 4.

The effect of chordwise flexibility on flapping foil propulsion in quiescent fluid

NASA Astrophysics Data System (ADS)

Shinde, Sachin; Arakeri, Jaywant

2010-11-01

Motivated to understand the role of wing flexibility of flying creatures during hovering, we experimentally study the effect of chordwise flexibility on the flow generated in quiescent fluid by a sinusoidally pitching rigid symmetrical foil with a flexible flap attached at the trailing edge. This foil produces a narrow, coherent jet containing reverse Karman vortex street, and a corresponding thrust. The thrust and flow is similar to that produced by a hovering bird or insect, however the mechanism seems to be different from known hovering mechanisms. Novelty of the present hovering mechanism is that the thrust generation is due to the coordinated pushing action of rigid foil and flexible flap. We identify the flow and vortex generation mechanism. This foil produces jet flows over a range of flapping frequencies and amplitudes. In contrast, the foil without flap i.e. with rigid trailing edge produces a weak, divergent jet that meanders randomly. Appending a flexible flap to the foil suppresses jet-meandering and strengthens the jet. Flexibility of flap is crucial in determining the flow structure. This study is useful in designing MAVs and thrusters.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muto, Hideshi; Ohshiro, Yukimitsu; Kawasaki, Katsunori

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 lessmore » 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.« less

Stripper foil failure modes and cures at the Oak Rdige Spallation Neutron Source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Plum, M.A.; Raparia, D.; Cousineau, S.M.

2011-03-28

The Oak Ridge Spallation Neutron Source comprises a 1 GeV, 1.5 MW linear accelerator followed by an accumulator ring and a liquid mercury target. To manage the beam loss caused by the H{sup 0} excited states created during the H{sup -} 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{sup -} beam, which circled aroundmore » 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 detail these and other interesting failure mechanisms and describe the improvements we have made to mitigate them.« less

Research with Large Area Imaging X-Ray Telescope Sounding Rocket Program

NASA Technical Reports Server (NTRS)

Gorenstein, Paul

1999-01-01

We are engaged in a program to develop focussing hard X-ray telescopes in a double conical or Wolter 1 geometry that function up to 100 keV by employing small graze angles and multilayer coatings. Directly polished substrates are not an option because they are too thick to be nested efficiently. The only alternative is to fabricate the very thin substrates by replication. Our objective is the production of integral cylindrical substrates because they should result in better angular resolution than segmented foil geometries. In addition, integral cylinders would be more resistant to possible stress from deep multilayer coatings than segmented ones. Both electroforming of nickel (method of SkX, JET-X, and XMM) and epoxy replication are under consideration. Both processes can utilize the same types of mandrels and separation agents- While electroforming can produce substrates that are thin, the high density of the nickel may result in high weight optics for some missions. For convenience, experimentation with replication and coating is being carried out initially on flats. Our replication studies include trials with gold and carbon separation agents. This paper reports on our efforts with epoxy replicated optics.

Trends in laser micromachining

NASA Astrophysics Data System (ADS)

Gaebler, Frank; van Nunen, Joris; Held, Andrew

2016-03-01

Laser Micromachining is well established in industry. Depending on the application lasers with pulse length from μseconds to femtoseconds and wavelengths from 1064nm and its harmonics up to 5μm or 10.6μm are used. Ultrafast laser machining using pulses with pico or femtosecond duration pulses is gaining traction, as it offers very precise processing of materials with low thermal impact. Large-scale industrial ultrafast laser applications show that the market can be divided into various sub segments. One set of applications demand low power around 10W, compact footprint and are extremely sensitive to the laser price whilst still demanding 10ps or shorter laser pulses. A second set of applications are very power hungry and only become economically feasible for large scale deployments at power levels in the 100+W class. There is also a growing demand for applications requiring fs-laser pulses. In our presentation we would like to describe these sub segments by using selected applications from the automotive and electronics industry e.g. drilling of gas/diesel injection nozzles, dicing of LED substrates. We close the presentation with an outlook to micromachining applications e.g. glass cutting and foil processing with unique new CO lasers emitting 5μm laser wavelength.

Strategy to Minimize Energetics Contamination at Military Testing/Training Ranges

DTIC Science & Technology

2005-09-01

exploding foil exploding foil initiator ) initiator will minimize the energetic material...i.e., exploding foil initiator P 𔃾 𔃾 𔃾 𔃾 4. Use an electronic S&A; i.e., high voltage driven semi-conductor bridge elements P ’ 𔃾 𔃾 𔃾 5. Use...alternatives Opportunity 1. Eliminate energetics 3. Use an electronic S&A; i.e., exploding foil initiator 1 3 3 -3 2 -6 -2 1 -2 -5 4. Use an

Study of irradiated Hadfield steel using transmission Mössbauer spectroscopy with high velocity resolution and conversion electron Mössbauer spectroscopy

NASA Astrophysics Data System (ADS)

Semionkin, V. A.; Neshev, F. G.; Tsurin, V. A.; Milder, O. B.; Oshtrakh, M. I.

2010-03-01

Proton irradiated Hadfield steel foil was studied using transmission Mössbauer spectroscopy with high velocity resolution and conversion electron Mössbauer spectroscopy. It was shown that proton irradiation leads to structural changes in the foil as well as to surface oxidation with ferric hydrous oxide formation (ferrihydrite). Moreover, oxidation on the foil underside was higher than on the foil right side.

Bending fatigue of electron-beam-welded foils. Application to a hydrodynamic air bearing in the Chrysler/DOE upgraded automotive gas tubine engine

NASA Technical Reports Server (NTRS)

Saltsman, J. F.; Halford, G. R.

1984-01-01

A hydrodynamic air bearing with a compliment surface is used in the gas generator of an upgraded automotive gas turbine engine. In the prototype design, the compliant surface is a thin foil spot welded at one end to the bearing cartridge. During operation, the foil failed along the line of spot welds which acted as a series of stress concentrators. Because of its higher degree of geometric uniformity, electron beam welding of the foil was selected as an alternative to spot welding. Room temperature bending fatigue tests were conducted to determine the fatigue resistance of the electron beam welded foils. Equations were determined relating cycles to crack initiation and cycles to failure to nominal total strain range. A scaling procedure is presented for estimating the reduction in cyclic life when the foil is at its normal operating temperature of 260 C (500 F).

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.

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.

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.

Mechanisms of submicron inclusion re-equilibration during host mineral deformation

NASA Astrophysics Data System (ADS)

Griffiths, Thomas; Habler, Gerlinde; Abart, Rainer; Rhede, Dieter; Wirth, Richard

2014-05-01

Both brittle and ductile deformation can facilitate re-equilibration of mineral inclusions. The presence of inclusions also influences stress and strain distribution in the host. The processes governing feedbacks between brittle deformation, ductile deformation, and inclusion re-equilibration have been studied using unique microstructures in Permian meta-pegmatite garnets from the Koralpe, Eastern Alps, Austria. Sampled almandine-spessartine garnets contain highly abundant submicron-sized inclusions, which originated during or subsequent to magmatic garnet growth. The Permian magmatic assemblages were affected by eclogite facies metamorphism during the Cretaceous tectono-metamorphic event. The meta-pegmatite garnet deformed crystal-plastically at this metamorphic stage (Bestmann et al. 2008) and the host-inclusion system was affected by partial recrystallization. Trails of coarser inclusions (1-10µm diameter) crosscut the magmatic submicron inclusion density zoning in the garnet, defining curviplanar geometrical surfaces in 3D. In 10-40µm broad 'bleaching zones' flanking inclusion trails, the original ≤1µm sized inclusions are not seen in the optical microscope or SEM, however inclusions <100nm are still abundant in TEM foils from these areas. From their microstructural characteristics it is inferred that the trails formed at sites of healed brittle cracks. FEG-microprobe data showed that inclusion-trails and associated bleaching zones can be formed isochemically, although some trails showed non-isochemical coarsening. In both cases no change in garnet major element composition was observed. EBSD mapping revealed two phenomena that were investigated by cutting targeted TEM foils. Firstly, bleaching zones are associated with systematic very low angle (ca. 0.5°) garnet lattice orientation changes along discrete boundaries. TEM foils transecting such a boundary show a lower concentration of dislocations than expected for the lattice rotation inferred from EBSD data, and no subgrain boundaries. Secondly, garnet lattice rotation of up to 10° around rational garnet crystal axes is observed in connection with some already coarsened inclusions. Strain concentrations are widespread in some trails, but rare in others. A TEM foil transecting a garnet domain with concentrated lattice rotation in association with inclusions reveals well developed polygonal subgrain walls with few free dislocations. Where dislocation density is greatest, almost no <100nm inclusions are observed, whereas these are more abundant in unstrained garnet domains despite the foil being located entirely within the optically visible bleaching zone. Chlorite inclusions and formation of etch pits at dislocations at the garnet-chlorite interface demonstrate the presence of fluid along subgrain boundaries during this second bleaching process. In summary, brittle deformation in these garnets led to enhanced transport and inclusion re-equilibration by coarsening, forming inclusion trails. The precise mechanism allowing enhanced transport is still to be determined and may have involved fluid supply with or without pipe diffusion along introduced dislocations. Later ductile deformation via dislocations, concentrated at already coarsened inclusions and enhanced by fluid availability, further affected the nanoinclusion population. The inclusion trail microstructure records complex small-scale interaction between deformation and reaction, shedding light on the mechanisms by which re-equilibration and strain localisation can influence each other in deforming host-inclusion systems. Bestmann et al. (2008) Journal of Structural Geology 30: 777-790

Shock compression response of highly reactive Ni + Al multilayered thin foils

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kelly, Sean C.; Thadhani, Naresh N., E-mail: naresh.thadhani@mse.gatech.edu

2016-03-07

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-compressionmore » 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 of shock-induced chemical reaction occurring in the time-scale of the high-pressure state. TEM characterization of recovered shock-compressed (unreacted) Ni + Al multilayered foils exhibits distinct features of constituent mixing revealing jetted layers and inter-mixed regions. These features were primarily observed in the proximity of the undulations present in the alternating layers of the Ni + Al starting foils, suggesting the important role of such instabilities in promoting shock-induced intermetallic-forming reactions in the fully dense highly exothermic multilayered thin foils.« less

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.

Optical Property Enhancement and Durability Evaluation of Heat Receiver Aperture Shield Materials

NASA Technical Reports Server (NTRS)

deGroh, Kim K.; Jaworske, Donald A.; Smith, Daniela C.

1998-01-01

Under the Solar Dynamic Flight Demonstration (SDFD) program, NASA Lewis Research Center worked with AlliedSignal Aerospace, the heat receiver contractor, on the development, characterization and durability testing of refractory metals to obtain appropriate optical and thermal properties for the SDFD heat receiver aperture shield. Molybdenum and tungsten foils were grit-blasted using silicon carbide or alumina grit under various grit-blasting conditions for optical property enhancement. Black rhenium coated tungsten foil was also evaluated. Tungsten, black rhenium-coated tungsten, and grit-blasted tungsten screens of various mesh sizes were placed over the pristine and grit-blasted foils for optical property characterization. Grit-blasting was found to be effective in decreasing the specular reflectance and the absorptance/emittance ratio of the refractory foils. The placement of a screen further enhanced these optical properties, with a grit-blasted screen over a grit-blasted foil producing the best results. Based on the optical property enhancement results, samples were tested for atomic oxygen and vacuum heat treatment durability. Grit-blasted (Al2O3 grit) 2 mil tungsten foil was chosen for the exterior layer of the SDFD heat receiver aperture shield. A 0.007 in. wire diameter, 20 x 20 mesh tungsten screen was chosen to cover the tungsten foil. Based on these test results, a heat receiver aperture shield test unit has been built with the screen covered grit-blast tungsten foil exterior layers. The aperture shield was tested and verified the thermal and structural durability of the outer foil layers during an off-pointing period.

Magnetic Fano resonances by design in symmetry broken THz meta-foils

PubMed Central

Wu, Jianfeng; Moser, Herbert O.; Li, Rujiang; Yang, Yihao; Jing, Liqiao; Chen, Hongsheng; Breese, Mark B. H.

2017-01-01

Magnetic Fano resonances in there-dimensional symmetry broken meta-foils at THz frequencies are theoretically and experimentally studied. Sharp Fano resonances occur due to the interference between different resonances and can be designed by choosing geometric parameters of the meta-foil. At the Fano resonances, the meta-foil supports antisymmetric modes, whereas, at the main resonance, only a symmetric mode exists. The meta-foil is left-handed at the Fano resonances and shows sharp peaks of the real part of the refractive index in transmission with small effective losses opening a way to very sensitive high-speed sensing of dielectric changes in the surrounding media and of mechanical configuration. PMID:28150797

Controlled porous pattern of anodic aluminum oxide by foils laminate approach.

PubMed

Wang, Gou-Jen; Peng, Chi-Sheng

2006-04-01

A novel, much simpler, and low-cost method to fabricate the porous pattern of the anodic aluminum oxide (AAO) based on the aluminum foils laminate approach was carried out. During our experiments, it was found that the pores of the AAO on the upper foil grew bi-directionally from both the top and the bottom surfaces. Experimental results further indicate that the upward porous pattern of the upper foil is determined by the surface structure of the bottom surface of the upper foil. The porous pattern of AAO can be controlled by a pre-made pattern on the bottom surface. Furthermore, no Aluminum (Al) layer removing process is required in this novel laminate method.

SNS STRIPPER FOIL FAILURE MODES AND THEIR CURES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Galambos, John D; Luck, Chris; Plum, Michael A

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 themore » improvements we have made to mitigate them.« less

High conductance surge cable

DOEpatents

Murray, Matthew M.; Wilfong, Dennis H.; Lomax, Ralph E.

1998-01-01

An electrical cable for connecting transient voltage surge suppressers to ectrical power panels. A strip of electrically conductive foil defines a longitudinal axis, with a length of an electrical conductor electrically attached to the metallic foil along the longitudinal axis. The strip of electrically conductive foil and the length of an electrical conductor are covered by an insulating material. For impedance matching purposes, triangular sections can be removed from the ends of the electrically conductive foil at the time of installation.

High conductance surge cable

DOEpatents

Murray, M.M.; Wilfong, D.H.; Lomax, R.E.

1998-12-08

An electrical cable for connecting transient voltage surge suppressors to electrical power panels. A strip of electrically conductive foil defines a longitudinal axis, with a length of an electrical conductor electrically attached to the metallic foil along the longitudinal axis. The strip of electrically conductive foil and the length of an electrical conductor are covered by an insulating material. For impedance matching purposes, triangular sections can be removed from the ends of the electrically conductive foil at the time of installation. 6 figs.

A Monte Carlo studies of the entrance foil material in a target assembly for FDG production

DOE Office of Scientific and Technical Information (OSTI.GOV)

Merouani, A.; El Khayati, N.; EL Ghayour, A.

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)

Slumping technique for the manufacturing of a representative x-ray grazing incidence mirror module for future space missions

NASA Astrophysics Data System (ADS)

Ghigo, Mauro; Proserpio, Laura; Basso, Stefano; Citterio, Oberto; Civitani, Marta M.; Pareschi, Giovanni; Salmaso, Bianca; Sironi, Giorgia; Spiga, Daniele; Tagliaferri, Giampiero; Vecchi, Gabriele; Zambra, Alberto; Parodi, Giancarlo; Martelli, Francesco; Gallieni, Daniele; Tintori, Matteo; Bavdaz, Marcos; Wille, Eric; Ferrario, Ivan; Burwitz, Vadim

2013-09-01

The Astronomical Observatory of Brera (INAF-OAB, Italy), with the financing support of the European Space Agency (ESA), has concluded a study regarding a glass shaping technology for the production of grazing incidence segmented x-ray optics. This technique uses a hot slumping phase, in which pressure is actively applied on thin glass foils being shaped, to form a cylindrical approximation of Wolter I x-ray segments, and a subsequent cold slumping phase, in which the final Wolter I profile is then freeze into the glass segments during their integration in elemental X-ray Optical Units. The final goal of this study was the manufacturing of a prototype containing a number of slumped pair plates (meaning parabola and hyperbola couples) having representative dimensions to be tested both in UV light and in x-rays at the Panter facility (Germany). In this paper, the INAF-OAB slumping technique, comprising a shaping step and an integration step is described, together with the results obtained on the manufactured prototype modules: the first prototype was aimed to test the ad-hoc designed and built semi-automatic Integration MAchine (IMA) and debug its control software. The most complete module comprises 40 slumped segments of Schott D263 glass type of dimension 200 mm x 200 mm and thickness of 0.4 mm, slumped on Zerodur K20 mould and stacked together through glued BK7 glass structural ribs to form the first entire x-ray optical module ever built totally composed by glass. A last prototype was aimed at demonstrate the use of Schott glass AF32 type instead of D263. In particular, a new hot slumping experimental set-up is described whose advantage is to permit a better contact between mould and glass during the shaping process. The integration procedure of the slumped segments into the elemental module is also reviewed.

Optical design for ATHENA X-ray telescope based on slumped mirror segments

NASA Astrophysics Data System (ADS)

Proserpio, Laura; Breunig, Elias; Friedrich, Peter; Winter, Anita

2014-07-01

The Hot and Energetic Universe will be the focus of future ESA missions: in late 2013 the theme was selected for the second large-class mission in the Cosmic Vision science program. Fundamental questions on how and why ordinary matter assemble into galaxies and clusters, and how black holes grow and influence their surroundings can be addressed with an advanced X-ray observatory. The currently proposed ATHENA mission presents all the potentiality to answer the outstanding questions. It is based on the heritage of XMM-Newton and on the previous studies for IXO mission. The scientific payload will require state of the art instrumentations. In particular, the baseline for the X-ray optical system, delivering a combination of large area, high angular resolution, and large field of view, is the Silicon Pore Optics technology (SPO) developed by ESA in conjunction with the Cosine Measurement Systems. The slumping technology is also under development for the manufacturing of future X-ray telescopes: for several years the Max Planck Institute for Extraterrestrial physics (MPE) has been involved in the analysis of the indirect slumping approach, which foresees the manufacturing of segmented X-ray shells by shaping thin glass foils at high temperatures over concave moulds so to avoid any contact of the optical surface with other materials during the process, preserving in this way the original X-ray quality of the glass surface. The paper presents an alternative optical design for ATHENA based on the use of thin glass mirror segments obtained through slumping.

Evaluation of the interaction between sodium hypochlorite and several formulations containing chlorhexidine and its effect on the radicular dentin--SEM and push-out bond strength analysis.

PubMed

Graziele Magro, Miriam; Kuga, Milton Carlos; Regina Victorino, Keli; Vázquez-Garcia, Fernando Antonio; Aranda-Garcia, Arturo Javier; Faria-Junior, Norberto Batista; Faria, Gisele; Luis Shinohara, André

2014-01-01

The aim of the current study was to evaluate the presence of debris and smear layer after endodontic irrigation with different formulations of 2% chlorhexidine gluconate (CHX) and its effects on the push-out bond strength of an epoxy-based sealer on the radicular dentin. One hundred extracted human canines were prepared to F5 instrument and irrigated with 2.5% sodium hypochlorite and 17% ethylenediaminetetraacetic acid. Fifty teeth were divided into five groups (n = 10), according to the final irrigation protocol with different 2% CHX formulations: G1 (control, no final rinse irrigation), G2 (CHX solution), G3 (CHX gel), G4 (Concepsis), and G5 (CHX Plus). In sequence, the specimens were submitted to scanning electron microscopy (SEM) analysis, in the cervical-medium and medium-apical segments, to evaluate the presence of debris and smear layer. The other 50 teeth were treated equally to a SEM study, but with the root canals filled with an epoxy-based endodontic sealer and submitted to a push-out bond strength test, in the cervical, middle, and apical thirds. G2, G3, G4, and G5 provided higher precipitation of the debris and smear layer than G1 (P < 0.05), but these groups were similar to each other (P > 0.05), in both segments. The values obtained in the push out test did not differ between groups, independent of the radicular third (P > 0.05). The CHXs formulations caused precipitation of the debris and smear layer on the radicular dentin, but these residues did not interfere in the push-out bond strength of the epoxy-based sealer. Copyright © 2013 Wiley Periodicals, Inc.

Intramuscular Connective Tissue Differences in Spastic and Control Muscle: A Mechanical and Histological Study

PubMed Central

de Bruin, Marije; Smeulders, Mark J.; Kreulen, Michiel; Huijing, Peter A.; Jaspers, Richard T

2014-01-01

Cerebral palsy (CP) of the spastic type is a neurological disorder characterized by a velocity-dependent increase in tonic stretch reflexes with exaggerated tendon jerks. Secondary to the spasticity, muscle adaptation is presumed to contribute to limitations in the passive range of joint motion. However, the mechanisms underlying these limitations are unknown. Using biopsies, we compared mechanical as well as histological properties of flexor carpi ulnaris muscle (FCU) from CP patients (n = 29) and healthy controls (n = 10). The sarcomere slack length (mean 2.5 µm, SEM 0.05) and slope of the normalized sarcomere length-tension characteristics of spastic fascicle segments and single myofibre segments were not different from those of control muscle. Fibre type distribution also showed no significant differences. Fibre size was significantly smaller (1933 µm2, SEM 190) in spastic muscle than in controls (2572 µm2, SEM 322). However, our statistical analyses indicate that the latter difference is likely to be explained by age, rather than by the affliction. Quantities of endomysial and perimysial networks within biopsies of control and spastic muscle were unchanged with one exception: a significant thickening of the tertiary perimysium (3-fold), i.e. the connective tissue reinforcement of neurovascular tissues penetrating the muscle. Note that this thickening in tertiary perimysium was shown in the majority of CP patients, however a small number of patients (n = 4 out of 23) did not have this feature. These results are taken as indications that enhanced myofascial loads on FCU is one among several factors contributing in a major way to the aetiology of limitation of movement at the wrist in CP and the characteristic wrist position of such patients. PMID:24977410

Foil chaff ejection systems for rocket-borne measurement of neutral winds in the mesosphere and lower thermosphere

NASA Astrophysics Data System (ADS)

Koizumi, Yoshiko; Shimoyama, Manabu; Oyama, Koh-Ichiro; Murayama, Yasuhiro; Tsuda, Toshitaka; Nakamura, Takuji

2004-07-01

The foil chaff technique has been used on microrockets such as "Viper" for a long time to measure neutral winds with high altitude resolution in the mesosphere and lower thermosphere. We have developed two new foil chaff storage and ejection systems for muti-instrumented sounding rockets. The first system uses a spring loaded split cylinder which holds the foil chaff, housed in an outer cylinder. The shaft of the split cylinder is kept in place by a lock plate and a stainless steel wire. The split cylinder is ejected by cutting the wire. The second system is of differential pressure type. The cap of an airtight cylinder has a shaft and a sponge piece for sweeping out the foil chaff. The cylinder is sealed at ground level and at the desired height of release, the cap comes out due to differential pressure and brings out the foil chaff. Both these systems were successfully tested on a Japanese sounding rocket in January 2000, releasing about 20 000 pieces of foil chaff during the rocket's descent. Neutral winds were measured in the height range of 85.5-95.0 km with a height resolution of 300 m.

Lenz’s law with aluminum foil and a lengthwise slit

NASA Astrophysics Data System (ADS)

Berls, Rob; Ruiz, Michael J.

2018-07-01

The classic demonstration illustrating Lenz’s law by dropping a magnet through a copper pipe is presented using household aluminum foil right out of the box. Then comes the surprise. The teacher presents an aluminum foil cylinder with a missing lengthwise slice (cut before class). Will the demonstration still work? Students are amazed at the result, described in this paper and included in our accompanying video (Ruiz 2018 Video: Lenz’s law with aluminum foil http://mjtruiz.com/ped/aluminum/).

Method for fabricating uranium foils and uranium alloy foils

DOEpatents

Hofman, Gerard L [Downers Grove, IL; Meyer, Mitchell K [Idaho Falls, ID; Knighton, Gaven C [Moore, ID; Clark, Curtis R [Idaho Falls, ID

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.

Description of Alloretochus sigillatus new species with comments and new distributional records for Alloretochus peruanicus (Ephemeroptera, Caenidae, Brachycercinae).

PubMed

Molineri, C

2014-06-19

Alloretochus sigillatus sp. nov. is described from adults of both sexes and eggs from Bolivia and Ecuador. Diagnostic characters of this species include: large body size, ratio pedicel/scape 1.75, presence of posteromedian projection on metanotum, characteristic blackish marks on abdominal terga, presence of vestiges of posterolateral projections on abdomen segments IV-VI, male subgenital plate broadly emarginated posteriorly, ratios forceps length/subbasal width 8.9, female sternum IX produced distally reaching apex of segment X, tapering distally with rounded apex, egg with 4 costae in lateral half. Additional characters for all stages and SEM photographs of eggs are provided for Alloretochus peruanicus, with new records of its presence in Argentina, Bolivia, Peru and Colombia.

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.

SU-E-T-25: Real Time Simulator for Designing Electron Dual Scattering Foil Systems.

PubMed

Carver, R; Hogstrom, K; Price, M; Leblanc, J; Harris, G

2012-06-01

To create a user friendly, accurate, real time computer simulator to facilitate the design of dual foil scattering systems for electron beams on radiotherapy accelerators. The simulator should allow for a relatively quick, initial design that can be refined and verified with subsequent Monte Carlo (MC) calculations and measurements. The simulator consists of an analytical algorithm for calculating electron fluence and a graphical user interface (GUI) C++ program. The algorithm predicts electron fluence using Fermi-Eyges multiple Coulomb scattering theory with a refined Moliere formalism for scattering powers. The simulator also estimates central-axis x-ray dose contamination from the dual foil system. Once the geometry of the beamline is specified, the simulator allows the user to continuously vary primary scattering foil material and thickness, secondary scattering foil material and Gaussian shape (thickness and sigma), and beam energy. The beam profile and x-ray contamination are displayed in real time. The simulator was tuned by comparison of off-axis electron fluence profiles with those calculated using EGSnrc MC. Over the energy range 7-20 MeV and using present foils on the Elekta radiotherapy accelerator, the simulator profiles agreed to within 2% of MC profiles from within 20 cm of the central axis. The x-ray contamination predictions matched measured data to within 0.6%. The calculation time was approximately 100 ms using a single processor, which allows for real-time variation of foil parameters using sliding bars. A real time dual scattering foil system simulator has been developed. The tool has been useful in a project to redesign an electron dual scattering foil system for one of our radiotherapy accelerators. The simulator has also been useful as an instructional tool for our medical physics graduate students. © 2012 American Association of Physicists in Medicine.

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.

Transient changes in electric fields induced by interaction of ultraintense laser pulses with insulator and metal foils: Sustainable fields spanning several millimeters

NASA Astrophysics Data System (ADS)

Inoue, Shunsuke; Tokita, Shigeki; Hashida, Masaki; Sakabe, Shuji

2015-04-01

The temporal evolutions of electromagnetic fields generated by the interaction between ultraintense lasers (1.3 ×1018 and 8.2 ×1018W /c m2 ) and solid targets at a distance of several millimeters from the laser-irradiated region have been investigated by electron deflectometry. For three types of foil targets (insulating foil, conductive foil, and insulating foil onto which a metal disk was deposited), transient changes in the fields were observed. We found that the direction, strength, and temporal evolution of the generated fields differ markedly for these three types of targets. The results provide an insight for studying the emission dynamics of laser-accelerated fast electrons.

Role of target material in proton acceleration from thin foils irradiated by ultrashort laser pulses.

PubMed

Tayyab, M; Bagchi, S; Ramakrishna, B; Mandal, T; Upadhyay, A; Ramis, R; Chakera, J A; Naik, P A; Gupta, P D

2014-08-01

We report on the proton acceleration studies from thin metallic foils of varying atomic number (Z) and thicknesses, investigated using a 45 fs, 10 TW Ti:sapphire laser system. An optimum foil thickness was observed for efficient proton acceleration for our laser conditions, dictated by the laser ASE prepulse and hot electron propagation behavior inside the material. The hydrodynamic simulations for ASE prepulse support the experimental observation. The observed maximum proton energy at different thicknesses for a given element is in good agreement with the reported scaling laws. The results with foils of different atomic number Z suggest that a judicious choice of the foil material can enhance the proton acceleration efficiency, resulting into higher proton energy.

Direct synthesis of carbon nanotubes using Cu-Sn catalyst on Cu substrates and their corrosion behavior in 0.6 M NaCl solution

NASA Astrophysics Data System (ADS)

Jeong, Namjo; Jwa, Eunjin; Kim, Chansoo; Choi, Ji Yeon; Nam, Joo-youn; Park, Soon-chul; Jang, Moon-seok

2017-11-01

We report the high-yield and large-area synthesis of a spaghetti-like carbon nanotubes (CNTs) on macroscopic Cu substrates (foil and foam) using a Cu-Sn alloy catalyst. In addition, we investigate the corrosion properties of the as-synthesized CNT/Cu foil system in 0.6 M NaCl solution. Electrochemical analysis showed that the corrosion resistance of the CNT/Cu foil system improved by a factor of ∼100 compared to the as-received Cu foil. Thus, it is concluded that a dense network of CNT was uniformly coated on the Cu foil and this coating functioned as an efficient barrier to corrosion under simulated seawater conditions.

Positron annihilation lifetime spectroscopy study of Kapton thin foils

NASA Astrophysics Data System (ADS)

Kanda, G. S.; Ravelli, L.; Löwe, B.; Egger, W.; Keeble, D. J.

2016-01-01

Variable energy positron annihilation lifetime spectroscopy (VE-PALS) experiments on polyimide material Kapton are reported. Thin Kapton foils are widely used in a variety of mechanical, electronic applications. PALS provides a sensitive probe of vacancy-related defects in a wide range of materials, including open volume in polymers. Varying the positron implantation energy enables direct measurement of thin foils. Thin Kapton foils are also commonly used to enclose the positron source material in conventional PALS measurements performed with unmoderated radionuclide sources. The results of depth-profiled positron lifetime measurements on 7.6 μm and 25 μm Kapton foils are reported and determine a dominant 385(1) ps lifetime component. The absence of significant nanosecond lifetime component due to positronium formation is confirmed.

The transonic multi-foil Augmentor-Wing

NASA Technical Reports Server (NTRS)

Farbridge, J. E.; Smith, R. C.

1977-01-01

The paper describes the development of a transonic blown multi-foil Augmentor-Wing airfoil section that has a thickness/chord (t/c) value of 0.18. In comparison with an unblown single-foil supercritical section of the same overall t/c the new multi-foil section is characterized by an increased drag rise Mach number, increased buffet boundaries, and a reduction in 'effective' drag due to blowing. Potential advantages of the Augmentor-Wing are considered and the testing of three high-speed models in a trisonic pressurized wind tunnel (possessing a two-dimensional transonic insert) is discussed. The data indicate that a very thick wing is feasible since separations toward the rear of the main foil can be controlled both by shroud location and augmentor blowing.

Early embryonic development of the head region of Gryllus assimilis Fabricius, 1775 (Orthoptera, Insecta).

PubMed

Liu, Yu; Maas, Andreas; Waloszek, Dieter

2010-09-01

We report our investigations on the embryonic development of Gryllus assimilis, with particular attention to the head. Significant findings revealed with scanning electron microscopy (SEM) images include: (1) the pre-antennal lobes represent the anterior-most segment that does not bear any appendages; (2) each of the lobes consists of central and marginal regions; (3) the central region thereof develops into the protocerebrum and the optic lobes, whereas the marginal region thereof becomes the anterior portion of the head capsule; (4) the initial position of the antennal segment is posterior to the mouth region; (5) appendage anlagen are transitorily present in the intercalary segment, and they later vanish together with the segment itself; (6) a bulged sternum appears to develop from the ventral surface of the mandibular, maxillary and labial segments. Embryonic features are then compared across the Insecta and further extended to the embryos of a spider (Araneae, Chelicerata). Striking similarities shared by the anterior-most region of the insect and spider embryos lead the authors to conclude that such comparison should be further undertaken to cover the entire Euarthropoda. This will help us to understand the embryology and evolution of the arthropod head. Copyright © 2010 Elsevier Ltd. All rights reserved.

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.

Remaining Technical Challenges and Future Plans for Oil-Free Turbomachinery

NASA Technical Reports Server (NTRS)

DellaCorte, Christopher; Bruckner, Robert J.

2010-01-01

The application of Oil-Free technologies (foil gas bearings, solid lubricants and advanced analysis and predictive modeling tools) to advanced turbomachinery has been underway for several decades. During that time, full commercialization has occurred in aircraft air cycle machines, turbocompressors and cryocoolers and ever-larger microturbines. Emerging products in the automotive sector (turbochargers and superchargers) indicate that high volume serial production of foil bearings is imminent. Demonstration of foil bearings in APU s and select locations in propulsion gas turbines illustrates that such technology also has a place in these future systems. Foil bearing designs, predictive tools and advanced solid lubricants have been reported that can satisfy anticipated requirements but a major question remains regarding the scalability of foil bearings to ever larger sizes to support heavier rotors. In this paper, the technological history, primary physics, engineering practicalities and existing experimental and experiential database for scaling foil bearings are reviewed and the major remaining technical challenges are identified.

Resistence seam welding thin copper foils

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hollar, D.L. Jr.

1991-02-01

Use of flat flexible circuits in the electronics industry is expanding. The term flexible circuits'' is defined here as copper foil which has been bonded to an insulating film such as Kapton film. The foil is photo processed to produce individual circuit paths similar to printed circuit boards. Another insulating film is laminated over the conductors to complete the flexible circuit. Flexible circuits, like multiwire cables, are susceptible to electromagnetic radiation (EMR) interference. On multiwire cables the interference problem is mitigated by adding a woven wire braid shielding over the conductors. Shielding on flexible circuits is accomplished by enclosing themore » circuits in a copper foil envelope. However, the copper foil must be electrically sealed around the flexcircuit to be effective. Ultimately, a resistance seam welding process and appropriate equipment were developed which would provide the required electrical seal between two layers of 2-oz (0.0028-inch thick) copper foil on a 1.1-inch wide, 30-inch long, 0.040-inch thick flexible circuit. 4 refs., 19 figs.« less

Inspection of cup-shaped steel parts from the I.D. side using eddy current

NASA Astrophysics Data System (ADS)

Griffiths, Erick W.; Pearson, Lee H.

2018-04-01

An eddy current method was developed to inspect cup-shaped steel parts from the I.D. side. During the manufacturing process of these parts, a thin Al tape foil is applied to the I.D. side of the part. One of the critical process parameters is that only one foil layer can be applied. An eddy current inspection system was developed to reject parts with more than one foil layer. The Al tape foil is cut to length to fit the inner diameter, however, after application of the foil there is a gap created between the beginning and end of the foil. It was found that this gap interfered with the eddy current inspection causing a false positive indication. To solve this problem a sensor design and data analysis process were developed to overcome the effects of these gaps. The developed system incorporates simultaneous measurements from multiple eddy current sensors and signal processing to achieve a reliable inspection.

The Chevron Foil Thrust Bearing: Improved Performance Through Passive Thermal Management and Effective Lubricant Mixing

NASA Technical Reports Server (NTRS)

Bruckner, Robert

2013-01-01

An improved foil thrust bearing is described that eliminates or reduces the need for forced cooling of the bearing foils while at the same time improves the load capacity of the bearing, enhances damping, provides overload tolerance, and eliminates the high speed load capacity drop-off that plagues the current state of the art. The performance improvement demonstrated by the chevron foil thrust bearing stems from a novel trailing edge shape that splays the hot lubricant in the thin film radially, thus preventing hot lubricant carry-over into the ensuing bearing sector. Additionally, the chevron shaped trailing edge induces vortical mixing of the hot lubricant with the gas that is naturally resident within the inter-pad region of a foil thrust bearing. The elimination of hot gas carry-over in combination with the enhanced mixing has enabled a completely passive thermally managed foil bearing design. Laboratory testing at NASA has confirmed the original analysis and reduced this concept to practice.

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.

Study of Electric Explosion of Flat Micron-Thick Foils at Current Densities of (5-50)×108 A/cm2

NASA Astrophysics Data System (ADS)

Shelkovenko, T. A.; Pikuz, S. A.; Tilikin, I. N.; Mingaleev, A. R.; Atoyan, L.; Hammer, D. A.

2018-02-01

Electric explosions of flat Al, Ti, Ni, Cu, and Ta foils with thicknesses of 1-16 μm, widths of 1-8 mm, and lengths of 5-11 mm were studied experimentally on the BIN, XP, and COBRA high-current generators at currents of 40-1000 kA and current densities of (5-50) × 108 A/cm2. The images of the exploded foils were taken at different angles to the foil surface by using point projection radiography with an X-pinch hot spot as the radiation source, the spatial resolution and exposure time being 3 μm and 50 ps, respectively, as well by the laser probing method with a spatial resolution of 20 μm and an exposure time of 180 ps. In the course of foil explosion, rapidly expanding objects resembling the core and corona of an exploded wire were observed. It is shown that the core of the exploded foil has a complicated time-varying structure.

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.

Braze system and method for reducing strain in a braze joint

DOEpatents

Cadden, Charles H.; Goods, Steven H.; Prantil, Vincent C.

2004-05-11

A system for joining a pair of structural members having widely differing coefficients of thermal expansion is disclosed. A mechanically "thick" foil is made by dispersing a refractory metal powder, such as molybdenum, niobium, tantalum, or tungsten into a quantity of a liquid, high expansion metal such as copper, silver, or gold, casting an ingot of the mixture, and then cutting sections of the ingot about 1 mm thick to provide the foil member. These foil members are shaped, and assembled between surfaces of structural members for joining, together with a layer of a braze alloy on either side of the foil member capable of wetting both the surfaces of the structural members and the foil. The assembled body is then heated to melt the braze alloy and join the assembled structure. The foil member subsequently absorbs the mechanical strain generated by the differential contraction of the cooling members that results from the difference in the coefficients of thermal expansion of the members.

Comet 81p/Wild 2: The Updated Stardust Coma Dust Fluence Measurement for Smaller (Sub 10-Micrometre) Particles

NASA Technical Reports Server (NTRS)

Price, M. C.; Kearsley, A. T.; Burchell, M. J.; Horz, Friedrich; Cole, M. J.

2009-01-01

Micrometre and smaller scale dust within cometary comae can be observed by telescopic remote sensing spectroscopy [1] and the particle size and abundance can be measured by in situ spacecraft impact detectors [2]. Initial interpretation of the samples returned from comet 81P/Wild 2 by the Stardust spacecraft [3] appears to show that very fine dust contributes not only a small fraction of the solid mass, but is also relatively sparse [4], with a low negative power function describing grain size distribution, contrasting with an apparent abundance indicated by the on-board Dust Flux Monitor Instrument (DFMI) [5] operational during the encounter. For particles above 10 m diameter there is good correspondence between results from the DFMI and the particle size inferred from experimental calibration [6] of measured aerogel track and aluminium foil crater dimensions (as seen in Figure 4 of [4]). However, divergence between data-sets becomes apparent at smaller sizes, especially submicrometre, where the returned sample data are based upon location and measurement of tiny craters found by electron microscopy of Al foils. Here effects of detection efficiency tail-off at each search magnification can be seen in the down-scale flattening of each scale component, but are reliably compensated by sensible extrapolation between segments. There is also no evidence of malfunction in the operation of DFMI during passage through the coma (S. Green, personal comm.), so can the two data sets be reconciled?

Advanced foil activation techniques for the measurement of within-pin distributions of the 63Cu(n,γ) 64Cu reaction rate in nuclear fuel

NASA Astrophysics Data System (ADS)

Macku, K.; Jatuff, F.; Murphy, M. F.; Joneja, O. P.; Bischofberger, R.; Chawla, R.

2006-06-01

Different foil activation techniques have been used for measuring spatial distributions of the 63Cu(n,γ) 64Cu reaction within two pins of a SVEA-96 Optima2 boiling water reactor fuel assembly, at the critical facility PROTEUS. This reaction is of interest because its 1/v cross-section gives it a good representation of the 235U fission rate. Initially, radial capture rate profiles were measured with mechanically punched copper foils. More detailed profiles were then determined by using a 0.2 mm copper wire spiral (˜200 μm resolution), as well as 5-, 10-, and 20-ring UV-lithography, electroplating, and molding (UV-LIGA) foils (up to a 100 μm resolution). For azimuthal measurements, apart from manually cut activation foils (into 8 sectors), 8- and 12-sector LIGA foils were used. The highly versatile LIGA foils have the additional advantage of being very easily separated into individual pieces after irradiation without the use of punches or other cutting tools. In order to account for the invasive character of the foil activation techniques, corrections to account for sample perturbations and for self-shielding effects were determined via simplified Monte Carlo (MCNP4C) modeling of the experimental setup. The final results from the various measurements of 63Cu(n,γ) 64Cu within-pin distributions have been compared with MCNP computations employing a detailed model of the full SVEA Optima2 fuel assembly.

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.

Variation across individuals and items determine learning outcomes from fast mapping.

PubMed

Coutanche, Marc N; Koch, Griffin E

2017-11-01

An approach to learning words known as "fast mapping" has been linked to unique neurobiological and behavioral markers in adult humans, including rapid lexical integration. However, the mechanisms supporting fast mapping are still not known. In this study, we sought to help change this by examining factors that modulate learning outcomes. In 90 subjects, we systematically manipulated the typicality of the items used to support fast mapping (foils), and quantified learners' inclination to employ semantic, episodic, and spatial memory through the Survey of Autobiographical Memory (SAM). We asked how these factors affect lexical competition and recognition performance, and then asked how foil typicality and lexical competition are related in an independent dataset. We find that both the typicality of fast mapping foils, and individual differences in how different memory systems are employed, influence lexical competition effects after fast mapping, but not after other learning approaches. Specifically, learning a word through fast mapping with an atypical foil led to lexical competition, while a typical foil led to lexical facilitation. This effect was particularly evident in individuals with a strong tendency to employ semantic memory. We further replicated the relationship between continuous foil atypicality and lexical competition in an independent dataset. These findings suggest that semantic properties of the foils that support fast mapping can influence the degree and nature of subsequent lexical integration. Further, the effects of foils differ based on an individual's tendency to draw-on the semantic memory system. Copyright © 2017 Elsevier Ltd. All rights reserved.

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.

The influence of perforation of foil reactors on greenhouse gas emission rates during aerobic biostabilization of the undersize fraction of municipal wastes.

PubMed

Stegenta, Sylwia; Dębowski, Marcin; Bukowski, Przemysław; Randerson, Peter F; Białowiec, Andrzej

2018-02-01

The opinion, that the use of foil reactors for the aerobic biostabilization of municipal wastes is not a valid method, due to vulnerability to perforation, and risk of uncontrolled release of exhaust gasses, was verified. This study aimed to determine the intensity of greenhouse gas (GHG) emissions to the atmosphere from the surface of foil reactors in relation to the extent of foil surface perforation. Three scenarios were tested: intact (airtight) foil reactor, perforated foil reactor, and torn foil reactor. Each experimental variant was triplicated, and the duration of each experiment cycle was 5 weeks. Temperature measurements demonstrated a significant decrease in temperature of the biostabilization in the torn reactor. The highest emissions of CO 2 , CO and SO 2 were observed at the beginning of the process, and mostly in the torn reactor. During the whole experiment, observed emissions of CO, H 2 S, NO, NO 2 , and SO 2 were at a very low level which in extreme cases did not exceed 0.25 mg t -1 .h -1 (emission of gasses mass unit per waste mass unit per unit time). The lowest average emissions of greenhouse gases were determined in the case of the intact reactor, which shows that maintaining the foil reactors in an airtight condition during the process is extremely important. Copyright © 2017 Elsevier Ltd. All rights reserved.

76 FR 66013 - Approval and Promulgation of Air Quality Implementation Plans; Missouri; Reasonably Available...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-25

... 57215): Paper, Film, and Foil Coatings; Metal Furniture Coatings; and Large Appliance Coatings... Emissions Paper, Film, and Foil Coatings. From Industrial Surface Coating Operations. 10 CSR 10-5.220... Paneling Coatings Paper, Film, and Foil Coatings Miscellaneous Industrial Adhesives Large Appliance...

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)

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 passive cooling mechanism. This cooling mechanism functions in such a way as to prevent used (higher temperature) lubricant from being carried over from the exit of one sector into the entry of the next sector of the foil bearing. The disclosed innovation is an improved foil bearing design that reduces or eliminates the need for force cooling of the bearing, while at the same time improving the load capacity of the bearing by at least a factor of two. These improvements are due to the elimination of lubricant carryover from the trailing edge of one sector into the leading edge of the next, and the mixing of used lubricant with the surrounding ambient fluid.

Repair of bone segment defects with surface porous fiber-reinforced polymethyl methacrylate (PMMA) composite prosthesis: histomorphometric incorporation model and characterization by SEM.

PubMed

Hautamäki, Mikko P; Aho, Allan J; Alander, Pasi; Rekola, Jami; Gunn, Jarmo; Strandberg, Niko; Vallittu, Pekka K

2008-08-01

Polymer technology has provided solutions for filling of bone defects in situations where there may be technical or biological complications with autografts, allografts, and metal prostheses. We present an experimental study on segmental bone defect reconstruction using a polymethylmethacrylate-(PMMA-) based bulk polymer implant prosthesis. We concentrated on osteoconductivity and surface characteristics. A critical size segment defect of the rabbit tibia in 19 animals aged 18-24 weeks was reconstructed with a surface porous glass fiber-reinforced (SPF) prosthesis made of polymethylmethacrylate (PMMA). The biomechanical properties of SPF implant material were previously adjusted technically to mimic the properties of normal cortical bone. A plain PMMA implant with no porosity or fiber reinforcement was used as a control. Radiology, histomorphometry, and scanning electron microscopy (SEM) were used for analysis of bone growth into the prosthesis during incorporation. The radiographic and histological incorporation model showed good host bone contact, and strong formation of new bone as double cortex. Histomorphometric evaluation showed that the bone contact index (BCI) at the posterior surface interface was higher with the SPF implant than for the control. The total appositional bone growth over the posterior surface (area %) was also stronger for the SPF implant than for controls. Both bone growth into the porous surface and the BCI results were related to the quality, coverage, and regularity of the microstructure of the porous surface. Porous surface structure enhanced appositional bone growth onto the SPF implant. Under load-bearing conditions the implant appears to function like an osteoconductive prosthesis, which enables direct mobilization and rapid return to full weight bearing.

Optimal endothelialisation of a new compliant poly(carbonate-urea)urethane vascular graft with effect of physiological shear stress.

PubMed

Salacinski, H J; Tai, N R; Punshon, G; Giudiceandrea, A; Hamilton, G; Seifalian, A M

2000-10-01

to define the optimal seeding conditions of a new stress free poly(carbonate-urea)urethane (CPU) graft with compliance similar to that of human artery with honeycomb structure engineered during the manufacturing process to enhance adhesion and growth of endothelial cells. (111)Indium-oxine radiolabeled human umbilical vein endothelial cells (HUVEC) were seeded onto CPU grafts at (a) concentrations from 2-24x10(5)cells/cm(2)and (b) incubated for 0.5, 1, 2, 4 and 6 h. Following incubation, graft segments were subjected to three washing/gamma counting procedures and scanning electron microscopy (SEM). Cell viability was measured using a modified Alamar blue(TM)assay. To test physiological retention a pulsatile flow phantom was used to subject optimally seeded (16x10(5), 4 h) CPU grafts to arterial shear stress for 6 h with real time acquisition of scintigraphic images of seeded grafts using a nuclear medicine gamma camera system. the seeding efficiency of 54+/-13% post three washes was achieved using 16x10(5)cells/cm(2). Similarly in SEM micrographs a seeding density of 16x10(5)cells/cm(2)resulted in a confluent monolayer. Seeded CPU segments incubated for 4 h exhibited significantly higher resistance to wash-off than segments incubated for 30 min (p <0.05). Exposure of seeded grafts to pulsatile shear stress resulted in some cell loss with 67+/-3% of cells adherent following 6 h of perfusion with ongoing metabolic activity. Thus, optimal conditions were 16x10(5)cells/cm(2)at 4 h. the optimal seeding conditions have been defined for "tissue-engineered" vascular graft which allow complete endothelialisation and high cell-to-substrate strength that resists hydrodynamic stress. Copyright 2000 Harcourt Publishers Ltd.

Process for producing molybdenum foil and collapsible tubing

NASA Technical Reports Server (NTRS)

Bretts, G. R.; Gavert, R. B.; Groschke, G. F.

1971-01-01

Manufacturing process produces molybdenum foil 0.002 cm thick and 305 m long, and forms foil into high-strength, thin-walled tubing which can be flattened for storage on a spool. Desirable metal properties include high thermal conductivity stiffness, yield and tensile stress, and low thermal expansion coeffecient.

Bonded foil pressure transducers

NASA Astrophysics Data System (ADS)

Daube, Bernie W.

The design of bonded-foil pressure transducers is discussed, with consideration given to individual components of both the electrical and the mechanical sections of the bonded-foil pressure transducers, as well as to the temperature control and the accuracy specification of these devices. Particular attention is given to applications of bonded foil pressure transducers, which include solid and liquid rocket engine testing for fuel and exhaust pressures, fuel and oil pressure monitoring on jet engines, and nuclear underground safety system pressure monitoring and nuclear test monitoring. A diagram of a transducer cutaway view is included.

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.

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.

Measuring Hydrogen Concentrations in Metals

NASA Technical Reports Server (NTRS)

Danford, M. D.

1985-01-01

Commercial corrosion-measurement system adapted to electrochemical determination of hydrogen concentrations in metals. New technique based on diffusion of hydrogen through foil specimen of metal. In sample holder, hydrogen produced on one side of foil, either by corrosion reaction or by cathodic current. Hydrogen diffused through foil removed on other side by constant anode potential, which leads to oxidation of hydrogen to water. Anode current is measure of concentration of hydrogen diffusing through foil. System used to study hydrogen uptake, hydrogen elimination by baking, effect of heat treatment, and effect of electroplating on high-strength steels.

Elevated-Temperature Tensile-Testing of Foil-Gage Metals

NASA Technical Reports Server (NTRS)

Blackburn, L. B.; Ellingsworth, J. R.

1986-01-01

Automated system for measuring strain in metal foils at temperatures above 500 degrees F (260 degrees C) uses mechanical extensometer and displacement transducer. System includes counterbalance feature, which eliminates weight contribution of extensometer and reduces grip pressure required for attachment to specimen. Counterbalancing feature overcomes two major difficulties in using extensometers with foil-gage specimens: (1) Weight of extensometer and transducer represents significant fraction of total load applied to specimen and may actually damage it; and (2) grip pressure required for attachment of extensometer to specimens may induce bending stresses in foil-gage materials.

Producing carbon stripper foils containing boron

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stoner, J. O. Jr.

2012-12-19

Parameters being actively tested by the accelerator community for the purpose of extending carbon stripper foil lifetimes in fast ion beams include methods of deposition, parting agents, mounting techniques, support (fork) materials, and inclusion of alloying elements, particularly boron. Specialized production apparatus is required for either sequential deposition or co-deposition of boron in carbon foils. A dual-use vacuum evaporator for arc evaporation of carbon and electron-beam evaporation of boron and other materials has been built for such development. Production of both carbon and boron foils has begun and improvements are in progress.

Method of Suppressing Sublimation in Advanced Thermoelectric Devices

NASA Technical Reports Server (NTRS)

Sakamoto, Jeffrey S. (Inventor); Caillat, Thierry (Inventor); Fleurial, Jean-Pierre (Inventor); Snyder, G. Jeffrey (Inventor)

2009-01-01

A method of applying a physical barrier to suppress thermal decomposition near a surface of a thermoelectric material including applying a continuous metal foil to a predetermined portion of the surface of the thermoelectric material, physically binding the continuous metal foil to the surface of the thermoelectric material using a binding member, and heating in a predetermined atmosphere the applied and physically bound continuous metal foil and the thermoelectric material to a sufficient temperature in order to promote bonding between the continuous metal foil and the surface of the thermoelectric material. The continuous metal foil forms a physical barrier to enclose a predetermined portion of the surface. Thermal decomposition is suppressed at the surface of the thermoelectric material enclosed by the physical barrier when the thermoelectric element is in operation.

Fast electron propagation in Ti foils irradiated with sub-picosecond laser pulses at Iλ{sup 2}>10{sup 18} Wcm{sup −2}μm{sup 2}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Makita, M.; Nersisyan, G.; McKeever, K.

2014-02-15

We have studied the propagation of fast electrons through laser irradiated Ti foils by monitoring the emission of hard X-rays and K-α radiation from bare foils and foils backed by a thick epoxy layer. Key observations include strong refluxing of electrons and divergence of the electron beam in the foil with evidence of magnetic field collimation. Our diagnostics have allowed us to estimate the fast electron temperature and fraction of laser energy converted to fast electrons. We have observed clear differences between the fast electron temperatures observed with bare and epoxy backed targets which may be due to the effectsmore » of refluxing.« less

A Systems Approach to the Solid Lubrication of Foil Air Bearings for Oil-Free Turbomachinery

NASA Technical Reports Server (NTRS)

DellaCorte, Christopher; Zaldana, Antonio R.; Radil, Kevin C.

2002-01-01

Foil air bearings are self-acting hydrodynamic bearings which rely upon solid lubricants to reduce friction and minimize wear during sliding which occurs at start-up and shut-down when surface speeds are too low to allow the formation of a hydrodynamic air film. This solid lubrication is typically accomplished by coating the non-moving foil surface with a thin, soft polymeric film. The following paper introduces a systems approach in which the solid lubrication is provided by a combination of self lubricating shaft coatings coupled with various wear resistant and lubricating foil coatings. The use of multiple materials, each providing different functions is modeled after oil-lubricated hydrodynamic sleeve bearing technology which utilizes various coatings and surface treatments in conjunction with oil lubricants to achieve optimum performance. In this study, room temperature load capacity tests are performed on journal foil air bearings operating at 14,000 rpm. Different shaft and foil coating technologies such as plasma sprayed composites, ceramic, polymer and inorganic lubricant coatings are evaluated as foil bearing lubricants. The results indicate that bearing performance is improved through the individual use of the lubricants and treatments tested. Further, combining several solid lubricants together yielded synergistically better results than any material alone.

Explosion of thin aluminum foils in air

NASA Astrophysics Data System (ADS)

Baksht, R.; Pokryvailo, A.; Yankelevich, Y.; Ziv, I.

2004-12-01

An inductive-based power supply (240μH, 50kA) was used for the investigation of the foil explosion process in the time range of 0.05ms

Development of damage suppression system using embedded SMA foil in CFRP laminates

NASA Astrophysics Data System (ADS)

Ogisu, Toshimichi; Nomura, Masato; Ando, Norio; Takaki, Junji; Kobayashi, Masakazu; Okabe, Tomonaga; Takeda, Nobuo

2001-07-01

Some recent studies have suggested possible applications of Shape Memory Alloy (SMA) for a smart health monitoring and suppression of damage growth. The authors have been conducting research and development studies on applications of embedded SMA foil actuators in CFRP laminates as the basic research for next generation aircrafts. First the effective surface treatment for improvement of bonding properties between SMA and CFRP was studied. It was certified that the anodic oxide treatment by 10% NaOH solution was the most effective treatment from the results of peel resistance test and shear strength test. Then, CFRP laminates with embedded SMA foils were successfully fabricated using this effective surface treatment. The damage behavior of quasi-isotropic CFRP laminates with embedded SMA foils was characterized in both quasi-static load-unload and fatigue tests. The relationship between crack density and applied strain was obtained. The recovery stress generated by embedded SMA foils could increase the onset strain of transverse cracking by 0.2%. The onset strain of delmination in CFRP laminates was also increased accordingly. The shear-lag analysis was also conducted to predict the damage evolution in CFRP laminates with embedded SMA foils. The adhesive layers on both sides of SMA foils were treated as shear elements. The theoretical analysis successfully predicted the experimental results.

Welding bulk metallic glass using nanostructured reactive multilayer foils

NASA Astrophysics Data System (ADS)

Trenkle, Jonathan C.

We have used Al/Ni reactive foils to weld Zr57Ti 5Cu20Ni8Al10 metallic glasses. The welds are a composite morphology comprised of glass ligaments and intermetallic AlNi (the product of the reactive foil). The presence of the presumably brittle intermetallic (in lieu of the glass) is expected to limit the mechanical properties of the welds. Based on fracture toughness measurements and the crack propagation paths, we conclude that virtually all of the toughness can be ascribed to the presence of the metallic glass ligaments. Increasing the pressure applied during welding increases the fraction of the joint made of these ligaments and so increases the fracture toughness as well. To eliminate the intermetallic from the weld altogether, we attempted to fabricate reactive mulitlayer foils that form an amorphous product by melting and cooling rapidly during a self-propagating reaction. We began with reactive foils with overall composition Zr2Ni but quickly determined that the foils did not fully melt. We then attempted to lower the melting temperature and increase the glass forming ability and the heat of mixing by adding Al and Cu. These foils again did not fully melt. Finally we systematically determined that foils of overall compositions Hf37Ni63, Ni 80P20, and Ni60P40, which are all known binary metallic glasses, will potentially melt during a self-propagating reaction. Knowledge of the phase transformations during a self-propagating reaction is necessary to engineer reactive foils for future applications. Furthermore, reactive foils provide an opportunity to study phase transformations under high heating rates not easily achievable. Characterizing the processes in the reaction zone however is challenging, requiring both temporal resolution better than ˜ 100 mus (the time required for the reaction front to pass a fixed location) and spatial resolution of < 100 mum (the approximate width of the reaction zone). Using synchrotron x-ray radiation, we have studied these phase transformations in situ in Al/Ni multilayers. Unlike previous annealing and quenching studies in these multilayers, we observed no metastable or intermediate phases.

Wake visualization of a heaving and pitching foil in a soap film

NASA Astrophysics Data System (ADS)

Muijres, Florian T.; Lentink, David

2007-11-01

Many fish depend primarily on their tail beat for propulsion. Such a tail is commonly modeled as a two-dimensional flapping foil. Here we demonstrate a novel experimental setup of such a foil that heaves and pitches in a soap film. The vortical flow field generated by the foil correlates with thickness variations in the soap film, which appear as interference fringes when the film is illuminated with a monochromatic light source (we used a high-frequency SOX lamp). These interference fringes are subsequently captured with high-speed video (500 Hz) and this allows us to study the unsteady vortical field of a flapping foil. The main advantage of our approach is that the flow fields are time and space resolved and can be obtained time-efficiently. The foil is driven by a flapping mechanism that is optimized for studying both fish swimming and insect flight inside and outside the behavioral envelope. The mechanism generates sinusoidal heave and pitch kinematics, pre-described by the non-dimensional heave amplitude (0-6), the pitch amplitude (0°-90°), the phase difference between pitch and heave (0°-360°), and the dimensionless wavelength of the foil (3-18). We obtained this wide range of wavelengths for a foil 4 mm long by minimizing the soap film speed (0.25 m s-1) and maximizing the flapping frequency range (4-25 Hz). The Reynolds number of the foil is of order 1,000 throughout this range. The resulting setup enables an effective assessment of vortex wake topology as a function of flapping kinematics. The efficiency of the method is further improved by carefully eliminating background noise in the visualization (e.g., reflections of the mechanism). This is done by placing mirrors at an angle behind the translucent film such that the camera views the much more distant and out-of-focus reflections of the black laboratory wall. The resulting high-quality flow visualizations require minimal image processing for flow interpretation. Finally, we demonstrate the effectiveness of our setup by visualizing the vortex dynamics of the flapping foil as a function of pitch amplitude by assessing the symmetry of the vortical wake.

Wake visualization of a heaving and pitching foil in a soap film

NASA Astrophysics Data System (ADS)

Muijres, Florian T.; Lentink, David

Many fish depend primarily on their tail beat for propulsion. Such a tail is commonly modeled as a twodimensional flapping foil. Here we demonstrate a novel experimental setup of such a foil that heaves and pitches in a soap film. The vortical flow field generated by the foil correlates with thickness variations in the soap film, which appear as interference fringes when the film is illuminated with a monochromatic light source (we used a high-frequency SOX lamp). These interference fringes are subsequently captured with high-speed video (500 Hz) and this allows us to study the unsteady vortical field of a flapping foil. The main advantage of our approach is that the flow fields are time and space resolved and can be obtained time-efficiently. The foil is driven by a flapping mechanism that is optimized for studying both fish swimming and insect flight inside and outside the behavioral envelope. The mechanism generates sinusoidal heave and pitch kinematics, pre-described by the non-dimensional heave amplitude (0-6), the pitch amplitude (0° - 90°), the phase difference between pitch and heave (0° - 360°), and the dimensionless wavelength of the foil (3-18). We obtained this wide range of wavelengths for a foil 4 mm long by minimizing the soap film speed (0.25 m s- 1) and maximizing the flapping frequency range (4-25 Hz). The Reynolds number of the foil is of order 1,000 throughout this range. The resulting setup enables an effective assessment of vortex wake topology as a function of flapping kinematics. The efficiency of the method is further improved by carefully eliminating background noise in the visualization (e.g., reflections of the mechanism). This is done by placing mirrors at an angle behind the translucent film such that the camera views the much more distant and out-of-focus reflections of the black laboratory wall. The resulting high-quality flow visualizations require minimal image processing for flow interpretation. Finally, we demonstrate the effectiveness of our setup by visualizing the vortex dynamics of the flapping foil as a function of pitch amplitude by assessing the symmetry of the vortical wake.

Intact suppression of increased false recognition in schizophrenia.

PubMed

Weiss, Anthony P; Dodson, Chad S; Goff, Donald C; Schacter, Daniel L; Heckers, Stephan

2002-09-01

Recognition memory is impaired in patients with schizophrenia, as they rely largely on item familiarity, rather than conscious recollection, to make mnemonic decisions. False recognition of novel items (foils) is increased in schizophrenia and may relate to this deficit in conscious recollection. By studying pictures of the target word during encoding, healthy adults can suppress false recognition. This study examined the effect of pictorial encoding on subsequent recognition of repeated foils in patients with schizophrenia. The study included 40 patients with schizophrenia and 32 healthy comparison subjects. After incidental encoding of 60 words or pictures, subjects were tested for recognition of target items intermixed with 60 new foils. These new foils were subsequently repeated following either a two- or 24-word delay. Subjects were instructed to label these repeated foils as new and not to mistake them for old target words. Schizophrenic patients showed greater overall false recognition of repeated foils. The rate of false recognition of repeated foils was lower after picture encoding than after word encoding. Despite higher levels of false recognition of repeated new items, patients and comparison subjects demonstrated a similar degree of false recognition suppression after picture, as compared to word, encoding. Patients with schizophrenia displayed greater false recognition of repeated foils than comparison subjects, suggesting both a decrement of item- (or source-) specific recollection and a consequent reliance on familiarity in schizophrenia. Despite these deficits, presenting pictorial information at encoding allowed schizophrenic subjects to suppress false recognition to a similar degree as the comparison group, implying the intact use of a high-level cognitive strategy in this population.

Progress in Chile in the development of the fission {sup 99}Mo production using modified CINTICHEM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schrader, R.; Klein, J.; Medel, J.

2008-07-15

Fission {sup 99}Mo will be produced in Chile irradiating low-enriched uranium (LEU) foil in a MTR research reactor. For the purpose of developing the capability to fabricate the target, which is done of uranium foil enclosed in swaged concentric aluminum tubes, dummy targets are being fabricated using 130 {mu}m copper foil instead of the uranium foil, wrapped in a 14{mu}m nickel fission-recoil barrier. Dummy targets using several dimensions of copper foil have been assembled; however, the emphasis is being set in targets fabricated using the dimensions of the LEU foil that KAERI will provide, i.e. 50 mm x 100mm xmore » 0.130 mm. The assembling of target using the last dimensions has not been free of difficulties. Neutronic calculations and preliminary thermal and fluid analyses were performed to estimate the fission products activity and the heat removal capability for a 13 grams LEU-foil annular target, which will be irradiated in the RECH-1 research reactor at the level power of 5 MW during 48 hours. In a fume hood, Cintichem processing of natural uranium shavings with the addition of different carriers were performed, obtaining recovery over 90% of the added Mo carrier. Expertise has been gained in (a) foil dissolution process in a dissolver locally designed, (b) in Mo precipitation process, and (c) preparation of the purification columns with AgC, C and HZrO. Additionally, the irradiated target cutting machine with an innovative design was finally assembled. (author)« less

Sex differences in mental rotation tasks: Not just in the mental rotation process!

PubMed

Boone, Alexander P; Hegarty, Mary

2017-07-01

The paper-and-pencil Mental Rotation Test (Vandenberg & Kuse, 1978) consistently produces large sex differences favoring men (Voyer, Voyer, & Bryden, 1995). In this task, participants select 2 of 4 answer choices that are rotations of a probe stimulus. Incorrect choices (i.e., foils) are either mirror reflections of the probe or structurally different. In contrast, in the mental rotation experimental task (Shepard & Metzler, 1971) participants judge whether 2 stimuli are the same but rotated or different by mirror reflection. The goal of the present research was to examine sources of sex differences in mental rotation, including the ability to capitalize on the availability of structure foils. In 2 experiments, both men and women had greater accuracy and faster reaction times (RTs) for structurally different compared with mirror foils in different versions of the Vandenberg and Kuse Mental Rotation Test (Experiment 1) and the Shepard and Metzler experimental task (Experiment 2). A significant male advantage in accuracy but not response time was found for both trial types. The male advantage was evident when all foils were structure foils so that mental rotation was not necessary (Experiment 3); however, when all foils were structure foils and participants were instructed to look for structure foils a significant sex difference was no longer evident (Experiment 4). Results suggest that the mental rotation process is not the only source of the sex difference in mental rotation tasks. Alternative strategy use is another source of sex differences in these tasks. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

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.

Measurements of Laser Generated X-ray Spectra from Irradiated Gold Foils

NASA Astrophysics Data System (ADS)

Davis, Joshua; Keiter, Paul; Drake, Paul; Klein, Sallee

2015-11-01

Soft x-ray sources may provide a means of driving photoionization fronts in materials with a Z >2. To generate these soft x-rays at a traditional UV laser facility, a gold converter foil can be implemented that absorbs the UV photons and heats up to act as a quasi-continuum blackbody emitter with a characteristic temperature of ~ 100eV. However, it takes time for the heating wave to propagate through the foil, with thicker foils having a longer delay before measureable emission is produced. Prior work has studied the emission characteristics of foil x-ray sources but was limited to laser pulses of 1ns or less. Our interest is in long duration sources (>1ns) which requires the use of thicker Au foils. To better understand how the increased foil thickness affects emission we have performed experiments at the Omega-60 laser facility studying the x-ray intensity and total emission time of 0.5, 1.0, and 2.0 μm thick gold foils driven by a 2kJ, 6ns laser pulse. This presentation will discuss the results of these experiments and will include a discussion of how these results compare with theoretical predictions. This work is funded by the U.S. DOE, through the NNSA-DS and SC-OFES Joint Program in HEDPLP, grant No. DE-NA0001840, and the NLUF Program, grant No. DE-NA0000850, and through LLE, Univ of Rochester by the NNSA/OICF under Agreement No. DE-FC52-08NA28302.

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…

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.

Stardust Interstellar Foils I1061N,1 and I1031N,1: First Results from Automated Crater Searches and Future Analytical Possibilities

NASA Astrophysics Data System (ADS)

Floss, C.; Allen, C.; Bajt, S.; Bechtel, H. A.; Borg, J.; Brenker, F.; Bridges, J.; Brownlee, D. E.; Burchell, M.; Burghammer, M.; Butterworth, A. L.; Cloetens, P.; Davis, A. M.; Doll, R.; Flynn, G. J.; Frank, D.; Gainsforth, Z.; Grün, E.; Heck, P. R.; Hillier, J. K.; Hoppe, P.; Howard, L.; Huss, G. R.; Huth, J.; Kearsley, A.; King, A. J.; Lai, B.; Leitner, J.; Lemelle, L.; Leonard, A.; Leroux, H.; Nittler, L. R.; Ogliore, R. C.; Ong, W. J.; Postberg, F.; Price, M. C.; Sandford, S. A.; Sans Tresseras, J. A.; Schmitz, S.; Schoonjans, T.; Schreiber, K.; Silversmit, G.; Siminonovici, A.; Srama, R.; Stadermann, F. J.; Stephan, T.; Stodolna, J.; Stroud, R. M.; Sutton, S. R.; Toucoulou, R.; Trieloff, M.; Tsou, P.; Tsuchiyama, A.; Tyliczszak, T.; Vekemans, B.; Vincze, L.; Westphal, A. J.; Zolensky, M. E.; 29,000 Stardust@Home Dusters

2011-03-01

Ten submicrometer (235-700-nm) craters were identified on Stardust interstellar foils 1061N and 1031N. The craters are distributed randomly over the foil areas, indicating that the high abundance observed is not due to clusters of secondary impacts.

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.

High quality ion acceleration through the interaction of two matched counterpropagating transversely polarized Gaussian lasers with a flat foil target

NASA Astrophysics Data System (ADS)

Zhou, Weijun; Hong, Xueren; Xie, Baisong; Yang, Yang; Wang, Li; Tian, Jianmin; Tang, Rongan; Duan, Wenshan

2018-02-01

In order to generate high quality ion beams through a relatively uniform radiation pressure acceleration (RPA) of a common flat foil, a new scheme is proposed to overcome the curve of the target while being radiated by a single transversely Gaussian laser. In this scheme, two matched counterpropagating transversely Gaussian laser pulses, a main pulse and an auxiliary pulse, impinge on the foil target at the meantime. It is found that in the two-dimensional (2D) particle-in-cell (PIC) simulation, by the restraint of the auxiliary laser, the curve of the foil can be effectively suppressed. As a result, a high quality monoenergetic ion beam is generated through an efficient RPA of the foil target. For example, two counterpropagating transversely circularly polarized Gaussian lasers with normalized amplitudes a1=120 and a2=30 , respectively, impinge on the foil target at the meantime, a 1.3 GeV monoenergetic proton beam with high collimation is obtained finally. Furthermore, the effects on the ions acceleration with different parameters of the auxiliary laser are also investigated.

Uranium Anodic Dissolution under Slightly Alkaline Conditions Progress Report Full-Scale Demonstration with DU Foil

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gelis, A.; Brown, M. A.; Wiedmeyer, S.

2014-02-18

Argonne National Laboratory (Argonne) is developing an alternative method for digesting irradiated low enriched uranium (LEU) foil targets to produce 99Mo in neutral/alkaline media. This method consists of the electrolytic dissolution of irradiated uranium foil in sodium bicarbonate solution, followed by precipitation of base-insoluble fission and activation products, and uranyl-carbonate species with CaO. The addition of CaO is vital for the effective anion exchange separation of 99MoO 4 2- from the fission products, since most of the interfering anions (e.g., CO 3 2-) are removed from the solution, while molybdate remains in solution. An anion exchange is used to retainmore » and to purify the 99Mo from the filtrate. The electrochemical dissolver has been designed and fabricated in 304 stainless-steel (SS), and tested for the dissolution of a full-size depleted uranium (DU) target, wrapped in Al foil. Future work will include testing with low-burn-up DU foil at Argonne and later with high-burn-up LEU foils at Oak Ridge National Laboratory.« less

Study of Electric Explosion of Flat Micron-Thick Foils at Current Densities of (5-50)×10 8A/cm 2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shelkovenko, T. A.; Pikuz, S. A.; Tilikin, I. N.

Electric explosions of flat Al, Тi, Ni, Cu, and Та foils with thicknesses of 1-16 μm, widths of 1-8 mm, and lengths of 5-11 mm were studied experimentally on the BIN, XP, and COBRA high-current generators at currents of 40-1000 kA and current densities of (5–50) × 10 8 A/cm 2. The images of the exploded foils were taken at different angles to the foil surface by using point projection radiography with an X-pinch hot spot as the radiation source, the spatial resolution and exposure time being 3 μm and 50 ps, respectively, as well by the laser probing methodmore » with a spatial resolution of 20 μm and an exposure time of 180 ps. In the course of foil explosion, rapidly expanding objects resembling the core and corona of an exploded wire were observed. It is shown that the core of the exploded foil has a complicated time-varying structure.« less

Study of Electric Explosion of Flat Micron-Thick Foils at Current Densities of (5-50)×10 8A/cm 2

DOE PAGES

Shelkovenko, T. A.; Pikuz, S. A.; Tilikin, I. N.; ...

2018-01-01

Electric explosions of flat Al, Тi, Ni, Cu, and Та foils with thicknesses of 1-16 μm, widths of 1-8 mm, and lengths of 5-11 mm were studied experimentally on the BIN, XP, and COBRA high-current generators at currents of 40-1000 kA and current densities of (5–50) × 10 8 A/cm 2. The images of the exploded foils were taken at different angles to the foil surface by using point projection radiography with an X-pinch hot spot as the radiation source, the spatial resolution and exposure time being 3 μm and 50 ps, respectively, as well by the laser probing methodmore » with a spatial resolution of 20 μm and an exposure time of 180 ps. In the course of foil explosion, rapidly expanding objects resembling the core and corona of an exploded wire were observed. It is shown that the core of the exploded foil has a complicated time-varying structure.« less

Selecting foils for identification lineups: matching suspects or descriptions?

PubMed

Tunnicliff, J L; Clark, S E

2000-04-01

Two experiments directly compare two methods of selecting foils for identification lineups. The suspect-matched method selects foils based on their match to the suspect, whereas the description-matched method selects foils based on their match to the witness's description of the perpetrator. Theoretical analyses and previous results predict an advantage for description-matched lineups both in terms of correctly identifying the perpetrator and minimizing false identification of innocent suspects. The advantage for description-matched lineups should be particularly pronounced if the foils selected in suspect-matched lineups are too similar to the suspect. In Experiment 1, the lineups were created by trained police officers, and in Experiment 2, the lineups were constructed by undergraduate college students. The results of both experiments showed higher suspect-to-foil similarity for suspect-matched lineups than for description-matched lineups. However, neither experiment showed a difference in correct or false identification rates. Both experiments did, however, show that there may be an advantage for suspect-matched lineups in terms of no-pick and rejection responses. From these results, the endorsement of one method over the other seems premature.

Selecting lineup foils in eyewitness identification experiments: experimental control and real-world simulation.

PubMed

Clark, S E; Tunnicliff, J L

2001-06-01

Experimental research on eyewitness identification follows a standard principle of experimental design. Perpetrator-present and perpetrator-absent lineups are constructed with the same foils, so that the two conditions are identical except for the presence or absence ofthe trueperpetrator ofthe crime. However, this aspect of the design simulates conditions that do not correspond to those of real criminal investigations. Specifically, these conditions can create perp-absent lineups in which the foils are selected based on their similarity to an unknown person--the real perpetrator. Analysis of the similarity relations predicts that when foils for perp-absent lineups are selected based on their match to the perpetrator the false identification rate will be lower than if the foils are selected based on their match to the innocent suspect. This prediction was confirmed in an experiment that compared these two perp-absent lineup conditions. These results suggest that false identification rates in previous experiments would have been higher if the foils had been selected based on their match to the innocent suspect, rather than the absent perpetrator.

Structural stiffness and Coulomb damping in compliant foil journal bearings: Theoretical considerations

NASA Astrophysics Data System (ADS)

Ku, C.-P. Roger; Heshmat, Hooshang

1994-07-01

Compliant foil bearings operate on either gas or liquid, which makes them very attractive for use in extreme environments such as in high-temperature aircraft turbine engines and cryogenic turbopumps. However, a lack of analytical models to predict the dynamic characteristics of foil bearings forces the bearing designer to rely on prototype testing, which is time-consuming and expensive. In this paper, the authors present a theoretical model to predict the structural stiffness and damping coefficients of the bump foil strip in a journal bearing or damper. Stiffness is calculated based on the perturbation of the journal center with respect to its static equilibrium position. The equivalent viscous damping coefficients are determined based on the area of a closed hysteresis loop of the journal center motion. The authors found, theoretically, that the energy dissipated from this loop was mostly contributed by the frictional motion between contact surfaces. In addition, the source and mechanism of the nonlinear behavior of the bump foil strips were examined. With the introduction of this enhanced model, the analytical tools are now available for the design of compliant foil bearings.

Prediction and characterization of heat-affected zone formation in tin-bismuth alloys due to nickel-aluminum multilayer foil reaction

DOE PAGES

Hooper, R. J.; Davis, C. G.; Johns, P. M.; ...

2015-06-26

Reactive multilayer foils have the potential to be used as local high intensity heat sources for a variety of applications. In this study, most of the past research effort concerning these materials have focused on understanding the structure-property relationships of the foils that govern the energy released during a reaction. To improve the ability of researchers to more rapidly develop technologies based on reactive multilayer foils, a deeper and more predictive understanding of the relationship between the heat released from the foil and microstructural evolution in the neighboring materials is needed. This work describes the development of a numerical modelmore » for the purpose of predicting heat affected zone size in substrate materials. The model is experimentally validated using a commercially available Ni-Al multilayer foils and alloys from the Sn-Bi binary system. To accomplish this, phenomenological models for predicting the variation of physical properties (i.e., thermal conductivity, density, and heat capacity) with temperature and composition in the Sn-Bi system were utilized using literature data.« less

Investigations on electroluminescent tapes and foils in relation to their applications in automotive

NASA Astrophysics Data System (ADS)

Plotog, Ioan

2015-02-01

The electroluminescent (EL) tapes or foils having barrier films for an additional level of protection against the toughest environments conditions, offer a large area of applications. The EL lights, due to their characteristics, began to be used not only in the entertainment industry, but also for automotive and aerospace applications. In the paper, the investigations regarding EL foils technical performances in relation to their applications as light sources in automotive ambient light were presented. The experiments were designed based on the results of EL foils electrical properties previous investigations done in laboratory conditions, taking into account the range of automotive ambient temperatures for sinusoidal alternative supply voltage. The measurements for different temperatures were done by keeping the EL foils into electronic controlled oven that ensures the dark enclosure offering conditions to use a lux-meter in order to measure and maintain under control light emission intensity. The experiments results define the EL foils characteristics as load in automotive ambient temperatures condition, assuring so the data for optimal design of a dedicated inverter.

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.

Multi-element microelectropolishing method

DOEpatents

Lee, Peter J.

1994-01-01

A method is provided for microelectropolishing a transmission electron microscopy nonhomogeneous multi-element compound foil. The foil is electrolyzed at different polishing rates for different elements by rapidly cycling between different current densities. During a first portion of each cycle at a first voltage a first element electrolyzes at a higher current density than a second element such that the material of the first element leaves the anode foil at a faster rate than the second element and creates a solid surface film, and such that the solid surface film is removed at a faster rate than the first element leaves the anode foil. During a second portion of each cycle at a second voltage the second element electrolyzes at a higher current density than the first element, and the material of the second element leaves the anode foil at a faster rate than the first element and creates a solid surface film, and the solid surface film is removed at a slower rate than the second element leaves the foil. The solid surface film is built up during the second portion of the cycle, and removed during the first portion of the cycle.

Stripper foil failure modes and cures at the Spallation Neutron Source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cousineau, Sarah M; Galambos, John D; Kim, Sang-Ho

2011-01-01

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 $H^0$ 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 foilmore » 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 detail these and other interesting failure mechanisms and describe the improvements we have made to mitigate them.« less

Analysis of Hybrid Type Boron-Doped Carbon Stripper Foils in J-PARC RCS

NASA Astrophysics Data System (ADS)

Yamazaki, Y.; Yoshimoto, M.; Takeda, O.; Kinsho, M.; Taguchi, T.; Yamamoto, S.; Kurihara, T.; Sugai, I.

2013-03-01

J-PARC (Japan-Proton Accelerator Research Complex) requires a carbon stripper foil to strip electrons from the H- beam supplied by the linac before injection into the Rapid Cycling Synchrotron (RCS) [1]. The foil thickness is about μm (200μg/cm2) corresponding to conversion efficiency of 99.7% from the primary H- beams of 181MeV energy to H+. We have successfully developed the Hybrid type thick Boron-doped Carbon (HBC) stripper foil, which showed a drastic improvement the lifetime without thickness reduction and shrinkage at the irradiated area. We started to study carbon stripper foils microscopically why carbon foils have considerable endurance for the beam impact by boron-doped. At first step, we made a comparison of ion irradiation effect between normal carbon and HBC by the electric microscope, ion-induced analysis. In particular, it seems that grain size of boron-rich area became much larger by irradiation for HBC. It was also observed that the boron-rich grain grew up by taking around material and generated pinholes more than 100 nm near itself consequently.

Process for forming a nickel foil with controlled and predetermined permeability to hydrogen

DOEpatents

Engelhaupt, Darell E.

1981-09-22

The present invention provides a novel process for forming a nickel foil having a controlled and predetermined hydrogen permeability. This process includes the steps of passing a nickel plating bath through a suitable cation exchange resin to provide a purified nickel plating bath free of copper and gold cations, immersing a nickel anode and a suitable cathode in the purified nickel plating bath containing a selected concentration of an organic sulfonic acid such as a napthalene-trisulfonic acid, electrodepositing a nickel layer having the thickness of a foil onto the cathode, and separating the nickel layer from the cathode to provide a nickel foil. The anode is a readily-corrodible nickel anode. The present invention also provides a novel nickel foil having a greater hydrogen permeability than palladium at room temperature.

Field and laboratory evaluations of commercial and next–generation alumina-forming austenitic foil for advanced recuperators

DOE PAGES

Pint, Bruce A.; Dryepondt, Sebastien N.; Brady, Michael P.; ...

2016-07-19

Alumina-forming austenitic (AFA) steels represent a new class of corrosion- and creep-resistant austenitic steels designed to enable higher temperature recuperators. Field trials are in progress for commercially rolled foil with widths over 39 cm. The first trial completed 3000 hrs in a microturbine recuperator with an elevated turbine inlet temperature and showed limited degradation. A longer microturbine trial is in progress. A third exposure in a larger turbine has passed 16,000 hrs. Furthermore, to reduce alloy cost and address foil fabrication issues with the initial AFA composition, several new AFA compositions are being evaluated in creep and laboratory oxidation testingmore » at 650–800 °C and the results compared to commercially fabricated AFA foil and conventional recuperator foil performance.« less

Growth of a sea urchin-like rutile TiO2 hierarchical microsphere film on Ti foil for a quasi-solid-state dye-sensitized solar cell.

PubMed

Ri, Jin Hyok; Wu, Shufang; Jin, Jingpeng; Peng, Tianyou

2017-11-30

A sea urchin-like rutile TiO 2 microsphere (RMS) film was fabricated on Ti foil via a hydrothermal process. The resulting rutile TiO 2 hierarchical microspheres with a diameter of 5-6 μm are composed of nanorods with a diameter of ∼200 nm and a length of 1-2 μm. The sea urchin-like hierarchical structure leads to the Ti foil-based RMS film possessing much better light-scattering capability in the visible region than the bare Ti foil. By using it as an underlayer of a nanosized anatase TiO 2 film (bTPP3) derived from a commercially available paste (TPP3), the corresponding bilayer Ti foil-based quasi-solid-state dye-sensitized solar cell (DSSC) only gives a conversion efficiency of 4.05%, much lower than the single bTPP3 film-based one on Ti foil (5.97%). By spin-coating a diluted TPP3 paste (sTPP3) on the RMS film prior to scraping the bTPP3 film, the resulting RMS/sTPP3/bTPP3 film-based DSSC achieves a significantly enhanced efficiency (7.27%). The electrochemical impedance spectra (EIS) show that the RMS/sTPP3/bTPP3 film possesses better electron transport capability and longer electron lifetime than the bTPP3 film. This work not only provides the first example of directly growing rutile TiO 2 hierarchically structured microsphere film on Ti foil suitable for replacing the rigid, heavy and expensive transparent conductive oxide (TCO) glass substrate to serve as a light-scattering underlayer of Ti foil-based quasi-solid-state DSSCs, but also paves a new route to develop Ti foil-based flexible DSSCs with high efficiency, low cost and a wide application field through optimizing the composition and structure of the photoanode.

A Versatile Model of Open-fracture Infection: a Contaminated Segmental Rat Femur Defect

DTIC Science & Technology

2014-06-01

has the effect of introducing an implant to lower the bacte- rial inoculum required for infection.5 A 6 mm critical defect is then created in the mid...103 1 × 104 1 × 105 Bone mean 0 7.21 × 104 7.83 × 105 1.11 × 105 1.51 × 105 Bone SEM 0 4.40 × 104 1.35 × 105 1.92 × 104 1.95 × 104 Implant mean 0 9.82...104 1.65 × 105 2.58 × 104 5.11 × 104 Implant SEM 0 5.10 × 104 1.61 × 105 3.16 × 103 9.11 × 103 12 8 4 4 3 6 6 0 0 Pr op or tio n of s am p le s w

Foil cooling for rep-rated electron beam pumped KrF lasers

NASA Astrophysics Data System (ADS)

Giuliani, J. L.; Hegeler, F.; Sethian, J. D.; Wolford, M. F.; Myers, M. C.; Abdel-Khalik, S.; Sadowski, D.; Schoonover, K.; Novak, V.

2006-06-01

In rep-rated electron beam pumped lasers the foil separating the vacuum diode from the laser gas is subject to repeated heating due to partial beam stopping. Three cooling methods are examined for the Electra KrF laser at the Naval Research Laboratory (NRL). Foil temperature measurements for convective cooling by the recirculating laser gas and by spray mist cooling are reported, along with estimates for thermal conductive foil cooling to the hibachi ribs. Issues on the application of each of these approaches to laser drivers in a fusion power plant are noted. Work supported by DOE/NNSA.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mukai, K., E-mail: mukai.kiyofumi@LHD.nifs.ac.jp; Peterson, B. J.; SOKENDAI

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.

Caracterisation des Ondes Radar de Surface par la Simulation Numerique et les Mesures GPR pour l'Auscultation en

NASA Astrophysics Data System (ADS)

Filali, Bilai

Graphene, as an advanced carbon nano-structure, has attracted a deluge of interest of scholars recently because of it's outstanding mechanical, electrical and thermal properties. There are several different ways to synthesis graphene in practical ways, such as Mechanical Exfoliation, Chemical Vapor Deposition (CVD), and Anodic Arc discharge. In this thesis a method of graphene synthesis in plasma will be discussed, in which this synthesis method is supported by the erosion of the anode material. This graphene synthesis method is one of the most practical methods which can provide high production rate. High purity of graphene flakes have been synthesized with an anodic arc method under certain pressure (about 500 torr). Raman spectrometer, Scanning Electron Microscope (SEM), Atomic Force Microscopy (AFM) and Transmission Electron Microscopy (TEM) have been utilized for characterization of the synthesis products. Arc produced graphene and commercially available graphene was compared by those machine and the difference lies in the number of layers, the thicknesses of each layer and the shape of the structure itself. Temperature dependence of the synthesis procedure has been studied. It has been found that the graphene can be produced on a copper foil substrate under temperatures near the melting point of copper. However, with a decrease in substrate temperature yields a transformation of the synthesized graphene into amorphous carbon. Glow discharge was utilized to functionalize grapheme. SEM and EDS observation indicated increases of oxygen content in the graphene after its exposure to glow discharge.

Cometary Dust Characteristics: Comparison of Stardust Craters with Laboratory Impacts

NASA Technical Reports Server (NTRS)

Kearsley, A. T.; Burchell, M. J.; Graham, G. A.; Horz, F.; Wozniakiewicz, P. A.; Cole, M. J.

2007-01-01

Aluminium foils exposed to impact during the passage of the Stardust spacecraft through the coma of comet Wild 2 have preserved a record of a wide range of dust particle sizes. The encounter velocity and dust incidence direction are well constrained and can be simulated by laboratory shots. A crater size calibration programme based upon buckshot firings of tightly constrained sizes (monodispersive) of glass, polymer and metal beads has yielded a suite of scaling factors for interpretation of the original impacting grain dimensions. We have now extended our study to include recognition of particle density for better matching of crater to impactor diameter. A novel application of stereometric crater shape measurement, using paired scanning electron microscope (SEM) images has shown that impactors of differing density yield different crater depth/diameter ratios. Comparison of the three-dimensional gross morphology of our experimental craters with those from Stardust reveals that most of the larger Stardust impacts were produced by grains of low internal porosity.

Novel p-n heterojunction copper phosphide/cuprous oxide photocathode for solar hydrogen production.

PubMed

Chen, Ying-Chu; Chen, Zhong-Bo; Hsu, Yu-Kuei

2018-08-01

A Copper phosphide (Cu 3 P) micro-rod (MR) array, with coverage by an n-Cu 2 O thin layer by electrodeposition as a photocathode, has been directly fabricated on copper foil via simple electro-oxidation and phosphidation for photoelectrochemical (PEC) hydrogen production. The morphology, structure, and composition of the Cu 3 P/Cu 2 O heterostructure are systematically analyzed using a scanning electron microscope (SEM), X-ray diffraction and X-ray photoelectron spectra. The PEC measurements corroborate that the p-Cu 3 P/n-Cu 2 O heterostructural photocathode illustrates efficient charge separation and low charge transfer resistance to achieve the highest photocurrent of 430 μA cm -2 that is greater than other transition metal phosphide materials. In addition, a detailed energy diagram of the p-Cu 3 P/n-Cu 2 O heterostructure was investigated using Mott-Schottky analysis. Our study paves the way to explore phosphide-based materials in a new class for solar energy applications. Copyright © 2018 Elsevier Inc. All rights reserved.

Effect of Processing Parameters on Thermal Cycling Behavior of Al2O3-Al2O3 Brazed Joints

NASA Astrophysics Data System (ADS)

Dandapat, Nandadulal; Ghosh, Sumana; Guha, Bichitra Kumar; Datta, Someswar; Balla, Vamsi Krishna

2016-10-01

In the present study, alumina ceramics were active metal brazed at different temperatures ranging from 1163 K to 1183 K (890 °C to 910 °C) using TICUSIL (68.8Ag-26.7Cu-4.5Ti in wt pct) foil as filler alloy of different thicknesses. The brazed joints were subjected to thermal cycling for 100 cycles between 323 K and 873 K (50 °C and 600 °C). The microstructural and elemental composition analysis of the brazed joints were performed by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) before and after thermal cycling. Helium (He) leak test and brazing strength measurement were also conducted after thermal cycling for 100 cycles. The joint could withstand up to 1 × 10-9 Torr pressure and brazing strength was higher than 20 MPa. The experimental results demonstrated that joints brazed at the higher temperature with thinner filler alloy produced strong Al2O3-Al2O3 joints.

Scanning electron microscopy of heat treated TiO2 nanotubes arrays obtained by anodic oxidation

NASA Astrophysics Data System (ADS)

Naranjo, D. I.; García-Vergara, S. J.; Blanco, S.

2017-12-01

Scanning electron microscopy was used to investigate the anatase-rutile transformation of self-organized TiO2 nanotubes obtained on titanium foil by anodizing and subsequent heat treatment. The anodizing was carried out at 20V in an 1% v/v HF acid and ethylene glycol:water (50:50) electrolyte at room temperature. The anodized samples were initially pre-heat treated at 450°C for 4 hours to modify the amorphous structure of TiO2 nanotubes into anatase structure. Then, the samples were heated between 600 to 800°C for different times, in order to promote the transformation to rutile structure. The formation of TiO2 nanotubes is evident by SEM images. Notably, when the samples are treated at high temperature, the formation of rutile crystals starts to become evident at the nanotubes located on the originally grain boundaries of the titanium. Thus, the anatase - rutile transformation has a close relationship with the microstructure of the titanium, more exactly with grain boundaries.

Highly Ordered TiO2 Microcones with High Rate Performance for Enhanced Lithium-Ion Storage.

PubMed

Rhee, Oonhee; Lee, Gibaek; Choi, Jinsub

2016-06-15

The perpendicularly oriented anatase TiO2 microcones for Li-ion battery application were synthesized via anodization of a Ti foil in aqueous HF + H3PO4 solution. The TiO2 microcones exhibited a high active surface area with a hollow core depending on applied voltage and reaction time, confirmed by SEM, XRD and TEM with EDS mapping. Li insertion/desertion into TiO2 microcones was evaluated for the first time in half-cell configuration in terms of various current density and long-term cyclability. The electrochemical experiments demonstrated that the as-prepared TiO2 microcones as anode material exhibited 3 times higher capacity as compared with TiO2 nanotubular structures, excellent rate performance (0.054 mAhcm(-2) even at 50 C) and reliable capacity retention during 500 cycles, which was attributed to facile diffusion of Li-ions induced in hollow anatase TiO2 microcones structure with multilayered nanofragment.

Deformation mechanism study of a hot rolled Zr-2.5Nb alloy by transmission electron microscopy. I. Dislocation microstructures in as-received state and at different plastic strains

DOE Office of Scientific and Technical Information (OSTI.GOV)

Long, Fei; Daymond, Mark R., E-mail: mark.daymond@queensu.ca; Yao, Zhongwen

Thin foil dog bone samples prepared from a hot rolled Zr-2.5Nb alloy have been deformed by tensile deformation to different plastic strains. The development of slip traces during loading was observed in situ through SEM, revealing that deformation starts preferentially in certain sets of grains during the elastic-plastic transition region. TEM characterization showed that sub-grain boundaries formed during hot rolling consisted of screw 〈a〉 dislocations or screw 〈c〉 and 〈a〉 dislocations. Prismatic 〈a〉 dislocations with large screw or edge components have been identified from the sample with 0.5% plastic strain. Basal 〈a〉 and pyramidal 〈c + a〉 dislocations were found in themore » sample that had been deformed with 1.5% plastic strain, implying that these dislocations require larger stresses to be activated.« less

Optimizing the 3D-reconstruction technique for serial block-face scanning electron microscopy.

PubMed

Wernitznig, Stefan; Sele, Mariella; Urschler, Martin; Zankel, Armin; Pölt, Peter; Rind, F Claire; Leitinger, Gerd

2016-05-01

Elucidating the anatomy of neuronal circuits and localizing the synaptic connections between neurons, can give us important insights in how the neuronal circuits work. We are using serial block-face scanning electron microscopy (SBEM) to investigate the anatomy of a collision detection circuit including the Lobula Giant Movement Detector (LGMD) neuron in the locust, Locusta migratoria. For this, thousands of serial electron micrographs are produced that allow us to trace the neuronal branching pattern. The reconstruction of neurons was previously done manually by drawing cell outlines of each cell in each image separately. This approach was very time consuming and troublesome. To make the process more efficient a new interactive software was developed. It uses the contrast between the neuron under investigation and its surrounding for semi-automatic segmentation. For segmentation the user sets starting regions manually and the algorithm automatically selects a volume within the neuron until the edges corresponding to the neuronal outline are reached. Internally the algorithm optimizes a 3D active contour segmentation model formulated as a cost function taking the SEM image edges into account. This reduced the reconstruction time, while staying close to the manual reference segmentation result. Our algorithm is easy to use for a fast segmentation process, unlike previous methods it does not require image training nor an extended computing capacity. Our semi-automatic segmentation algorithm led to a dramatic reduction in processing time for the 3D-reconstruction of identified neurons. Copyright © 2016 Elsevier B.V. All rights reserved.

Coordinated Microanalyses of Seven Particles of Probable Interstellar Origin from the Stardust Mission

NASA Technical Reports Server (NTRS)

Westphal, Andrew J.; Stroud, Rhonda M.; Bechtel, Hans A.; Brenker, Frank E.; Butterworth, Anna L.; Flynn, George J.; Frank, David R.; Gainsforth, Zack; Hillier, Jon K.; Postberg, Frank;

Thin silicon foils produced by epoxy-induced spalling of silicon for high efficiency solar cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martini, R., E-mail: roberto.martini@imec.be; imec, Kapeldreef 75, 3001 Leuven; Kepa, J.

2014-10-27

We report on the drastic improvement of the quality of thin silicon foils produced by epoxy-induced spalling. In the past, researchers have proposed to fabricate silicon foils by spalling silicon substrates with different stress-inducing materials to manufacture thin silicon solar cells. However, the reported values of effective minority carrier lifetime of the fabricated foils remained always limited to ∼100 μs or below. In this work, we investigate epoxy-induced exfoliated foils by electron spin resonance to analyze the limiting factors of the minority carrier lifetime. These measurements highlight the presence of disordered dangling bonds and dislocation-like defects generated by the exfoliation process.more » A solution to remove these defects compatible with the process flow to fabricate solar cells is proposed. After etching off less than 1 μm of material, the lifetime of the foil increases by more than a factor of 4.5, reaching a value of 461 μs. This corresponds to a lower limit of the diffusion length of more than 7 times the foil thickness. Regions with different lifetime correlate well with the roughness of the crack surface which suggests that the lifetime is now limited by the quality of the passivation of rough surfaces. The reported values of the minority carrier lifetime show a potential for high efficiency (>22%) thin silicon solar cells.« less

Heat Transfer in High Temperature Multilayer Insulation

NASA Technical Reports Server (NTRS)

Daryabeigi, Kamran; Miller, Steve D.; Cunnington, George R.

2007-01-01

High temperature multilayer insulations have been investigated as an effective component of thermal-protection systems for atmospheric re-entry of reusable launch vehicles. Heat transfer in multilayer insulations consisting of thin, gold-coated, ceramic reflective foils and Saffil(TradeMark) fibrous insulation spacers was studied both numerically and experimentally. A finite volume numerical thermal model using combined conduction (gaseous and solid) and radiation in porous media was developed. A two-flux model with anisotropic scattering was used for radiation heat transfer in the fibrous insulation spacers between the reflective foils. The thermal model was validated by comparison with effective thermal conductivity measurements in an apparatus based on ASTM standard C201. Measurements were performed at environmental pressures in the range from 1x10(exp -4) to 760 torr over the temperature range from 300 to 1300 K. Four multilayer samples with nominal densities of 48 kg/cu m were tested. The first sample was 13.3 mm thick and had four evenly spaced reflective foils. The other three samples were 26.6 mm thick and utilized either one, two, or four reflective foils, located near the hot boundary with nominal foil spacing of 1.7 mm. The validated thermal model was then used to study relevant design parameters, such as reflective foil spacing and location in the stack-up and coating of one or both sides of foils.

Preliminary Analysis for an Optimized Oil-Free Rotorcraft Engine Concept

NASA Technical Reports Server (NTRS)

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

2008-01-01

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 paper 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.

Microbial communities responsible for the degradation of poly(lactic acid)/poly(3-hydroxybutyrate) blend mulches in soil burial respirometric tests.

PubMed

Jeszeová, Lenka; Puškárová, Andrea; Bučková, Mária; Kraková, Lucia; Grivalský, Tomáš; Danko, Martin; Mosnáčková, Katarína; Chmela, Štefan; Pangallo, Domenico

2018-06-22

The microbial communities responsible for the degradation of poly(lactic acid)/poly(3-hydroxybutyrate) (PLA/PHB) blend foils were investigated in 1 year long laboratory soil burial experiments. Different PLA/PHB foils were tested: (a) PLA/PHB original transparent foil, (b) PLA/PHB carbon black filled foil and (c) PLA/PHB black foil previously exposed for 90 days to sun light. The microbiome diversity of these three types of foil was compared with that identified from soil/perlite sample at the beginning of experiment and that developed on a cellulose mat. Culture-dependent and culture-independent (DGGE-cloning) approaches together with PLA, PHB and PLA/PHB degradation plate assays were employed. The cultivation strategy combined with degradation tests permitted the isolation and evaluation of several PLA/PHB blend degrading microorganisms such as members of the genera Bacillus, Paenibacillus, Streptomyces, Rhodococcus, Saccharothrix, Arthrobacter, Aureobasidium, Mortierella, Absidia, Actinomucor, Bjerkandera, Fusarium, Trichoderma and Penicillium. The DGGE-cloning investigation increased the information about the microbial communities occurring during bioplastic degradation detecting several bacterial and fungal taxa and some of them (members of the orders Anaerolineales, Selenomonadales, Thelephorales and of the genera Pseudogymnoascus and Pseudeurotium) were revealed here for the first time. This survey showed the microbiome colonizing PLA/PHB blend foils and permitted the isolation of several microorganisms able to degrade the tested polymeric blends.

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.

Instability Coupling Experiments*

NASA Astrophysics Data System (ADS)

Chrien, R. E.; Hoffman, N. M.; Magelssen, G. R.; Schappert, G. T.; Smitherman, D. P.

1996-11-01

The coupling of Richtmyer-Meshkov (RM) and ablative Rayleigh-Taylor (ART) instabilities is being studied with indirectly-driven planar foil experiments on the Nova laser at Livermore. The foil is attached to a 1.6-mm-diameter, 2.75-mm-long Au hohlraum driven by a 2.2-ns long, 1:5-contrast-ratio shaped laser pulse. A shock is generated in 35-μm or 86-μm thick Al foils with a 50-μm-wavelength, 4-μm-amplitude sinusoidal perturbation on its rear surface. In some experiments, the perturbation is applied to a 10-μm Be layer on the Al. A RM instability develops when the shock encounters the perturbed surface. The flow field of the RM instability can ``feed out'' to the ablation surface of the foil and provide the seed for ART perturbation growth. Face-on and side-on x-radiography are used to observe areal density perturbations in the foil. For the 86-μm foil, the perturbation arrives at the ablation surface while the hohlraum drive is dropping and the data are consistent with RM instability alone. For the 35-μm foil, the perturbation feeds out while the hohlraum drive is close to its peak and the data appear to show strong ART perturbation growth. Comparisons with LASNEX simulations will be presented. *This work supported under USDOE contract W-7405-ENG-36.

Foil Strain Gauges Using Piezoresistive Carbon Nanotube Yarn: Fabrication and Calibration

PubMed Central

Góngora-Rubio, Mário R.; Kiyono, César Y.; Mello, Luis A. M.; Cardoso, Valtemar F.; Rosa, Reinaldo L. S.; Kuebler, Derek A.; Brodeur, Grace E.; Alotaibi, Amani H.; Coene, Marisa P.; Coene, Lauren M.; Jean, Elizabeth; Santiago, Rafael C.; Oliveira, Francisco H. A.; Rangel, Ricardo; Thomas, Gilles P.; Belay, Kalayu; da Silva, Luciana W.; Moura, Rafael T.; Seabra, Antonio C.; Silva, Emílio C. N.

2018-01-01

Carbon nanotube yarns are micron-scale fibers comprised by tens of thousands of carbon nanotubes in their cross section and exhibiting piezoresistive characteristics that can be tapped to sense strain. This paper presents the details of novel foil strain gauge sensor configurations comprising carbon nanotube yarn as the piezoresistive sensing element. The foil strain gauge sensors are designed using the results of parametric studies that maximize the sensitivity of the sensors to mechanical loading. The fabrication details of the strain gauge sensors that exhibit the highest sensitivity, based on the modeling results, are described including the materials and procedures used in the first prototypes. Details of the calibration of the foil strain gauge sensors are also provided and discussed in the context of their electromechanical characterization when bonded to metallic specimens. This characterization included studying their response under monotonic and cyclic mechanical loading. It was shown that these foil strain gauge sensors comprising carbon nanotube yarn are sensitive enough to capture strain and can replicate the loading and unloading cycles. It was also observed that the loading rate affects their piezoresistive response and that the gauge factors were all above one order of magnitude higher than those of typical metallic foil strain gauges. Based on these calibration results on the initial sensor configurations, new foil strain gauge configurations will be designed and fabricated, to increase the strain gauge factors even more. PMID:29401745

Lenz's Law with Aluminum Foil and a Lengthwise Slit

ERIC Educational Resources Information Center

Berls, Rob; Ruiz, Michael J.

2018-01-01

The classic demonstration illustrating Lenz's law by dropping a magnet through a copper pipe is presented using household aluminum foil right out of the box. Then comes the surprise. The teacher presents an aluminum foil cylinder with a missing lengthwise slice (cut before class). Will the demonstration still work? Students are amazed at the…

Hot foil transducer skin friction sensor

NASA Technical Reports Server (NTRS)

Vranas, T. (Inventor)

1982-01-01

The device utilizes foil transducers with only one edge exposed to the fluid flow. The surfaces are polished producing a foil transducer that does not generate turbulence while sufficiently thick to carry the required electrical current for high temperature fluid flow. The assembly utilizes a precut layered metal sandwich with attached electrodes eliminating a need for welding and individual sensor calibration.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lula, J.W.

Copper foil adhesion to polyimide/glass prepreg was evaluated. Typical peel strength obtained between prepreg and the smooth side of the copper foil was 1 to 3 lb./in. width. Peel strength between prepreg and the rough side of the copper foil ranged between 6 and 7 lb./in. width. An alternate test for evaluating the integrity of multilayer printed wiring boards is described.

Annealing of (DU-10Mo)-Zr Co-Rolled Foils

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pacheco, Robin Montoya; Alexander, David John; Mccabe, Rodney James

2017-01-20

Producing uranium-10wt% molybdenum (DU-10Mo) foils to clad with Al first requires initial bonding of the DU-10Mo foil to zirconium (Zr) by hot rolling, followed by cold rolling to final thickness. Rolling often produces wavy (DU-10Mo)-Zr foils that should be flattened before further processing, as any distortions could affect the final alignment and bonding of the Al cladding to the Zr co-rolled surface layer; this bonding is achieved by a hot isostatic pressing (HIP) process. Distortions in the (DU-10Mo)-Zr foil may cause the fuel foil to press against the Al cladding and thus create thinner or thicker areas in the Almore » cladding layer during the HIP cycle. Post machining is difficult and risky at this stage in the process since there is a chance of hitting the DU-10Mo. Therefore, it is very important to establish a process to flatten and remove any waviness. This study was conducted to determine if a simple annealing treatment could flatten wavy foils. Using the same starting material (i.e. DU-10Mo coupons of the same thickness), five different levels of hot rolling and cold rolling, combined with five different annealing treatments, were performed to determine the effect of these processing variables on flatness, bonding of layers, annealing response, microstructure, and hardness. The same final thickness was reached in all cases. Micrographs, textures, and hardness measurements were obtained for the various processing combinations. Based on these results, it was concluded that annealing at 650°C or higher is an effective treatment to appreciably reduce foil waviness.« less

Experimental study on the use of spacer foils in two-step putty and wash impression procedures using silicone impression materials.

PubMed

Mann, Karsten; Davids, Andreas; Range, Ursula; Richter, Gert; Boening, Klaus; Reitemeier, Bernd

2015-04-01

The 2-step putty and wash impression technique is commonly used in fixed prosthodontics. However, cutting sluiceways to allow the light-body material to drain is time-consuming. A solution might be the use of a spacer foil. The purpose of this study was to evaluate the influence of spacer foil on the margin reproduction and dimensional accuracy of 2-step putty and wash impressions. Two methods of creating space for the wash material in a 2-step putty and wash impression were compared: the traditional cutout technique and a spacer foil. Eleven commercially available combinations of silicone impression materials were included in the study. The impressions and the cast production were carried out under standardized conditions. All casts were measured with a 3-dimensional (3D) coordinate measuring machine. Preparation margin reproduction and the diameters and spacing of the stone cast dies were measured (α=.05). The 2 methods showed significant differences (P<.05) in the reproduction of the preparation margins (complete reproduction cutout, 90% to 98%; foil, 74% to 91%). The use of a foil resulted in greater dimensional accuracy of the cast dies compared to the cutout technique. Cast dies from the cutout technique were significantly smaller than the metallic original cast (cutout median, 4.55 mm to 4.61 mm; foil median, 4.61 to 4.64). Spacing between the dies revealed only a few additional significant differences between the techniques. When spacer foils were used, dies were obtained that better corresponded to the original tooth. Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Note: Radial-thrust combo metal mesh foil bearing for microturbomachinery

NASA Astrophysics Data System (ADS)

Park, Cheol Hoon; Choi, Sang Kyu; Hong, Doo Euy; Yoon, Tae Gwang; Lee, Sung Hwi

2013-10-01

This Note proposes a novel radial-thrust combo metal mesh foil bearing (MMFB). Although MMFBs have advantages such as higher stiffness and damping over conventional air foil bearings, studies related to MMFBs have been limited to radial MMFBs. The novel combo MMFB is composed of a radial top foil, thrust top foils, and a ring-shaped metal mesh damper—fabricated by compressing a copper wire mesh—with metal mesh thrust pads for the thrust bearing at both side faces. In this study, the combo MMFB was fabricated in half-split type to support the rotor for a micro gas turbine generator. The manufacture and assembly process for the half-split-type combo MMFB is presented. In addition, to verify the proposed combo MMFB, motoring test results up to 250 000 rpm and axial displacements as a function of rotational speed are presented.

Note: Radial-thrust combo metal mesh foil bearing for microturbomachinery.

PubMed

Park, Cheol Hoon; Choi, Sang Kyu; Hong, Doo Euy; Yoon, Tae Gwang; Lee, Sung Hwi

2013-10-01

This Note proposes a novel radial-thrust combo metal mesh foil bearing (MMFB). Although MMFBs have advantages such as higher stiffness and damping over conventional air foil bearings, studies related to MMFBs have been limited to radial MMFBs. The novel combo MMFB is composed of a radial top foil, thrust top foils, and a ring-shaped metal mesh damper--fabricated by compressing a copper wire mesh--with metal mesh thrust pads for the thrust bearing at both side faces. In this study, the combo MMFB was fabricated in half-split type to support the rotor for a micro gas turbine generator. The manufacture and assembly process for the half-split-type combo MMFB is presented. In addition, to verify the proposed combo MMFB, motoring test results up to 250,000 rpm and axial displacements as a function of rotational speed are presented.

Application study on aircraft structures of CFRP laminates with embedded SMA foils

NASA Astrophysics Data System (ADS)

Ogisu, Toshimichi; Nomura, Masato; Ando, Norio; Takaki, Junji; Takeda, Nobuo

2002-07-01

This paper reports some research results for the application study of the smart materials an structural using Shape Memory Alloy (SMA) foils. First, the authors acquired the recovery strain of CFRP laminates generated by the recovery stress of the pre-strained SMA foils. Then, the quasi-static load-unload tests were conducted using several kinds of quasi-isotropic CFRP laminates with embedded SMA foils. Micro-mechanics of damage behavior due to the effects of the recovery strain and the first transverse crack strain were discussed. The improvement of maximum 40 percent for the onset strain of the transverse cracks and maximum 60 percent for the onset strain of delamination were achieved for CFRP laminates with embedded pre-strained SMA foils compared with standard CFRP laminates. Furthermore, the authors conducted the structural element test for application to actual structures. Testing technique and the manufacturing technique of the structural element specimen were established.

The possibility of using platinum foils with a rippled surface as diffraction gratings

NASA Astrophysics Data System (ADS)

Korsukov, V. E.; Ankudinov, A. V.; Butenko, P. N.; Knyazev, S. A.; Korsukova, M. M.; Obidov, B. A.; Shcherbakov, I. P.

2014-09-01

The atomic structure and surface relief of thin cold-rolled platinum foils upon recrystallization annealing and loading under ultrahigh vacuum conditions have been studied by low energy electron diffraction (LEED), atomic force microscopy (AFM), and scanning tunneling microscopy (STM). The surface of samples upon high-temperature annealing and subsequent uniaxial extension of recrystallized Pt foils represents a fractal structure of unidirectional ripples on various spatial scales. The total fractal dimension of this surface is D GW = 2.3, while the fractal dimensions along and across ripples are D ‖ ≈ 1 and D ⊥ ≈ 1.3, respectively. The optical spectra of a halogen lamp and a PRK-2 mercury lamp were recorded using these rippled Pt foils as reflection diffraction gratings. It is shown that Pt foils with this surface relief can be used as reflection diffraction gratings for electromagnetic radiation in a broad spectral range.

Ion track etching revisited: I. Correlations between track parameters in aged polymers

NASA Astrophysics Data System (ADS)

Fink, D.; Muñoz H., G.; García A., H.; Vacik, J.; Hnatowicz, V.; Kiv, A.; Alfonta, L.

2018-04-01

Some yet poorly understood problems of etching of pristine and swift heavy ion track-irradiated aged polymers were treated, by applying conductometry across the irradiated foils during etching. The onset times of etchant penetration across pristine foils, and the onset times of the different etched track regimes in irradiated foils were determined for polymers of various proveniences, fluences and ages, as well as their corresponding etching speeds. From the results, correlations of the parameters with each other were deduced. The normalization of these parameters enables one to compare irradiated polymer foils of different origin and treatment with one another. In a number of cases, also polymeric gel formation and swelling occur which influence the track etching behaviour. The polymer degradation during aging influences the track etching parameters, which differ from each other on both sides of the foils. With increasing sample age, these differences increase.

The measurement of radiation exposure of astronauts by radiochemical techniques

NASA Technical Reports Server (NTRS)

Brodzinski, R. L.

1971-01-01

Gamma analyses of the neutron-activated fecal samples from the Apollo 12 and 13 missions were completed, and the data are being evaluated. Samples of the exposed Apollo 12 solar wind composition foil and blank foils were obtained for analysis of the Po-2/0 (Pb-210, Rn-222) content. It is expected that the determination of the Po-210 content of these foils will yield the concentration of radon atoms incident on the foil while exposed to the lunar atmosphere, and this indirectly will permit an estimate of the average uranium concentration of the lunar surface. Proposals to measure the cosmic-ray intensity and energy spectra inside and outside of late Apollo and Project Skylab spacecraft by exposing and subsequently analyzing pure metal foils, and to measure the elemental mass balance in Project Skylab astronauts by instrumental neutron activation analysis of the intake and excreta are summarized.

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.

Stratification in Al and Cu foils exploded in vacuum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baksht, R. B.; Electrical Discharge and Plasma Laboratory, Tel Aviv University, Tel Aviv 6997801; Rousskikh, A. G.

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 instabilitymore » that develops due to an increase in the resistivity of the metal with temperature.« less

Degradation of polyester polyurethane by a newly isolated soil bacterium, Bacillus subtilis strain MZA-75.

PubMed

Shah, Ziaullah; Krumholz, Lee; Aktas, Deniz Fulya; Hasan, Fariha; Khattak, Mutiullah; Shah, Aamer Ali

2013-11-01

A polyurethane (PU) degrading bacterial strain MZA-75 was isolated from soil through enrichment technique. The bacterium was identified through 16S rRNA gene sequencing, the phylogenetic analysis indicated the strain MZA-75 belonged to genus Bacillus having maximum similarity with Bacillus subtilis strain JBE0016. The degradation of PU films by strain MZA-75 in mineral salt medium (MSM) was analyzed by scanning electron microscopy (SEM), fourier transform infra-red spectroscopy (FT-IR) and gel permeation chromatography (GPC). SEM revealed the appearance of widespread cracks on the surface. FTIR spectrum showed decrease in ester functional group. Increase in polydispersity index was observed in GPC, which indicates chain scission as a result of microbial treatment. CO2 evolution and cell growth increased when PU was used as carbon source in MSM in Sturm test. Increase in both cell associated and extracellular esterases was observed in the presence of PU indicated by p-Nitrophenyl acetate (pNPA) hydrolysis assay. Analysis of cell free supernatant by gas chromatography-mass spectrometry (GC-MS) revealed that 1,4-butanediol and adipic acid monomers were produced. Bacillus subtilis strain MZA-75 can degrade the soft segment of polyester polyurethane, unfortunately no information about the fate of hard segment could be obtained. Growth of strain MZA-75 in the presence of these metabolites indicated mineralization of ester hydrolysis products into CO2 and H2O.

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.

Elevated Temperature Tensile Tests on DU–10Mo Rolled Foils

DOE Office of Scientific and Technical Information (OSTI.GOV)

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.

PERSONNEL NEUTRON DOSIMETER

DOEpatents

Fitzgerald, J.J.; Detwiler, C.G. Jr.

1960-05-24

A description is given of a personnel neutron dosimeter capable of indicating the complete spectrum of the neutron dose received as well as the dose for each neutron energy range therein. The device consists of three sets of indium foils supported in an aluminum case. The first set consists of three foils of indium, the second set consists of a similar set of indium foils sandwiched between layers of cadmium, whereas the third set is similar to the second set but is sandwiched between layers of polyethylene. By analysis of all the foils the neutron spectrum and the total dose from neutrons of all energy levels can be ascertained.

Rematching AGS Booster synchrotron injection lattice for smaller transverse beam emittances

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, C.; Beebe-Wang, J.; Brown, K.

2017-01-25

The polarized proton beam is injected into the booster via the charge-exchange (H- to H+) scheme. The emittance growth due to scattering at the stripping foil is proportional to the beta functions at the foil. It was demonstrated that the current scheme of reducing the beta functions at the stripping foil preserves the emittance better; however the betatron tunes are above but very close to half integer. Due to concern of space charge and half integer in general, options of lattice designs aimed towards reducing the beta functions at the stripping foil with tunes at more favorable places are explored.

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.

Dye foils with increased durability for passive Q-switching in a 1064 nm laser

NASA Astrophysics Data System (ADS)

Mierczyk, Z.; Kwasny, M.; Czeszko, J.

The results of spectral gel permeation chromatography and differential thermal analysis investigations of structures of dye foils consisting of bis-(4-dimethyl-amino-dithio-benzil)-nickel dye suspended in polymethylmethacrylate matrix, to be used for passive Q-switching in a 1064 nm laser, are reported. Results of experimental measurements and of numerical calculations of thermal and generating properties, and of the endurance of passive foil type Q-switches in the resonator of YAG:Nd(3+) laser are also presented. Optimization of polymerization conditions has enabled the production of dye foils with high thermal and photochemical resistance, which give stable operation of a giant pulsed laser.

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.

An Oil-Free Thrust Foil Bearing Facility Design, Calibration, and Operation

NASA Technical Reports Server (NTRS)

Bauman, Steve

2005-01-01

New testing capabilities are needed in order to foster thrust foil air bearing technology development and aid its transition into future Oil-Free gas turbines. This paper describes a new test apparatus capable of testing thrust foil air bearings up to 100 mm in diameter at speeds to 80,000 rpm and temperatures to 650 C (1200 F). Measured parameters include bearing torque, load capacity, and bearing temperatures. This data will be used for design performance evaluations and for validation of foil bearing models. Preliminary test results demonstrate that the rig is capable of testing thrust foil air bearings under a wide range of conditions which are anticipated in future Oil-Free gas turbines. Torque as a function of speed and temperature corroborates results expected from rudimentary performance models. A number of bearings were intentionally failed with no resultant damage whatsoever to the test rig. Several test conditions (specific speeds and loads) revealed undesirable axial shaft vibrations which have been attributed to the magnetic bearing control system and are under study. Based upon these preliminary results, this test rig will be a valuable tool for thrust foil bearing research, parametric studies and technology development.

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.

Experimental Investigation of the Electrothermal Instability on Planar Foil Ablation Experiments

NASA Astrophysics Data System (ADS)

Steiner, Adam; Patel, Sonal; Yager-Elorriaga, David; Jordan, Nicholas; Gilgenbach, Ronald; Lau, Y. Y.

2014-10-01

The electrothermal instability (ETI) is an important early-time physical effect on pulsed power foil ablation experiments due to its ability to seed the destructive magneto-Rayleigh-Taylor (MRT) instability. ETI occurs whenever electrical resistivity has temperature dependence; when resistivity increases with temperature, as with solid metal liners or foils, ETI forms striation structures perpendicular to current flow. These striations provide an initial perturbation for the MRT instability, which is the dominant late-time instability in planar foil ablations. The MAIZE linear transformer driver was used to drive current pulses of approximately 600 kA into 400 nm-thick aluminum foils in order to study ETI in planar geometry. Shadowgraph images of the aluminum plasmas were taken for multiple shots at various times within approximately 50 ns of current start. Fourier analysis extracted the approximate wavelengths of the instability structures on the plasma-vacuum interface. Surface metrology of pre-shot foils was performed to provide a comparison between surface roughness features and resulting plasma structure. This work was supported by US DoE. S.G. Patel and A.M. Steiner supported by NPSC funded by Sandia. D.A. Yager supported by NSF fellowship Grant # DGE 1256260.

Fabrication of full-color GaN-based light-emitting diodes on nearly lattice-matched flexible metal foils.

PubMed

Kim, Hyeryun; Ohta, Jitsuo; Ueno, Kohei; Kobayashi, Atsushi; Morita, Mari; Tokumoto, Yuki; Fujioka, Hiroshi

2017-05-18

GaN-based light-emitting diodes (LEDs) have been widely accepted as highly efficient solid-state light sources capable of replacing conventional incandescent and fluorescent lamps. However, their applications are limited to small devices because their fabrication process is expensive as it involves epitaxial growth of GaN by metal-organic chemical vapor deposition (MOCVD) on single crystalline sapphire wafers. If a low-cost epitaxial growth process such as sputtering on a metal foil can be used, it will be possible to fabricate large-area and flexible GaN-based light-emitting displays. Here we report preparation of GaN films on nearly lattice-matched flexible Hf foils using pulsed sputtering deposition (PSD) and demonstrate feasibility of fabricating full-color GaN-based LEDs. It was found that introduction of low-temperature (LT) grown layers suppressed the interfacial reaction between GaN and Hf, allowing the growth of high-quality GaN films on Hf foils. We fabricated blue, green, and red LEDs on Hf foils and confirmed their normal operation. The present results indicate that GaN films on Hf foils have potential applications in fabrication of future large-area flexible GaN-based optoelectronics.

Efficacy of lead foil for reducing doses in the head and neck: a simulation study using digital intraoral systems

PubMed Central

Silva, A I V; Brasil, D M; Vasconcelos, K F; Haiter Neto, F; Boscolo, F N

2015-01-01

Objectives: To assess the efficacy of lead foils in reducing the radiation dose received by different anatomical sites of the head and neck during periapical intraoral examinations performed with digital systems. Methods: Images were acquired through four different manners: phosphor plate (PSP; VistaScan® system; Dürr Dental GmbH, Bissingen, Germany) alone, PSP plus lead foil, complementary metal oxide semiconductor (CMOS; DIGORA® Toto, Soredex®, Tuusula, Finland) alone and CMOS plus lead foil. Radiation dose was measured after a full-mouth periapical series (14 radiographs) using the long-cone paralleling technique. Lithium fluoride (LiF 100) thermoluminescent dosemeters were placed in an anthropomorphic phantom at points corresponding to the tongue, thyroid, crystalline lenses, parotid glands and maxillary sinuses. Results: Dosemeter readings demonstrated the efficacy of the addition of lead foil in the intraoral digital X-ray systems provided in reducing organ doses in the selected structures, approximately 32% in the PSP system and 59% in the CMOS system. Conclusions: The use of lead foils associated with digital X-ray sensors is an effective alternative for the protection of different anatomical sites of the head and neck during full-mouth periapical series acquisition. PMID:26084474

Multi-element microelectropolishing method

DOEpatents

Lee, P.J.

1994-10-11

A method is provided for microelectropolishing a transmission electron microscopy nonhomogeneous multi-element compound foil. The foil is electrolyzed at different polishing rates for different elements by rapidly cycling between different current densities. During a first portion of each cycle at a first voltage a first element electrolyzes at a higher current density than a second element such that the material of the first element leaves the anode foil at a faster rate than the second element and creates a solid surface film, and such that the solid surface film is removed at a faster rate than the first element leaves the anode foil. During a second portion of each cycle at a second voltage the second element electrolyzes at a higher current density than the first element, and the material of the second element leaves the anode foil at a faster rate than the first element and creates a solid surface film, and the solid surface film is removed at a slower rate than the second element leaves the foil. The solid surface film is built up during the second portion of the cycle, and removed during the first portion of the cycle. 10 figs.

Cavitation Characteristics of a NACA 63-424 Hydrofoil and Performance Comparison with a Bidirectional Version of the Foil

NASA Astrophysics Data System (ADS)

Nedyalkov, Ivaylo; Wosnik, Martin

2012-11-01

A NACA 63-424 hydrofoil with a 75 mm chord and a 152 mm span was tested in the recently renovated 6-inch high-speed water tunnel at the University of New Hampshire. The NACA 63-424 foil is being considered for use on rotors of marine hydrokinetic turbines, including the US Department of Energy Reference Horizontal Axis Turbine (RHAT) for tidal and ocean current applications. For various angles of attack, the foil was tested at speeds ranging from 2 m/s to 12 m/s. Pressure in the test section was varied independently. For each angle, speed and pressure setting, high speed videos were recorded (at 3600 frames per second and above). Cavitation inception and desinance were obtained. Lift and drag were measured using a new 2-component force balance. In tidal turbines applications, bidirectional foils do not require pitch control, hence the experiments were repeated for a bidirectional version of the NACA 63-424 foil and the characteristics of the two foils were compared. The results can be used to predict cavitation inception and performance of marine hydrokinetic turbines, for a given site, deployment depth and and tip speed ratio.

Design of a medium size x-ray mirror module based on thin glass foils

NASA Astrophysics Data System (ADS)

Basso, Stefano; Civitani, Marta; Pareschi, Giovanni

2016-07-01

The hot slumping glass technology for X-ray mirror is under development and in the last years the results have been improved. Nustar is the first X-ray telescope based on slumped glass foils and it benefit is the low cost compared to the direct polishing of glass. With the slumping technique it is possible to maintain the glass mass to low values with respect to the direct polishing, but in general the angular resolution is worst. A further technique based on glass is the cold shaping of foils. The improved capabilities of manufacturing thin glass foils, pushed by the industrial application for screens, open new possibilities for X-ray mirror. The increase in strength of thin tempered glasses, the reduction of thickness errors and the good roughness of flat foils are potentially great advantages. In this paper a design of a mediumsize X-ray mirror module is analysed. It is based on integration of glass foils, stacked directly on a supporting structure that is part of the X-ray telescope using stiffening ribs as spacer between foils. The alignment of each stack is performed directly into the integration machine avoiding the necessity of the alignment of different stacked modules. A typical module (glass optic and metallic structure) provides an effective area of 10 cm2/kg at 1 keV (with a mass of about 50- 100 kg and a focal length of 10 m).

Alpha Oscillations during Incidental Encoding Predict Subsequent Memory for New "Foil" Information.

PubMed

Vogelsang, David A; Gruber, Matthias; Bergström, Zara M; Ranganath, Charan; Simons, Jon S

2018-05-01

People can employ adaptive strategies to increase the likelihood that previously encoded information will be successfully retrieved. One such strategy is to constrain retrieval toward relevant information by reimplementing the neurocognitive processes that were engaged during encoding. Using EEG, we examined the temporal dynamics with which constraining retrieval toward semantic versus nonsemantic information affects the processing of new "foil" information encountered during a memory test. Time-frequency analysis of EEG data acquired during an initial study phase revealed that semantic compared with nonsemantic processing was associated with alpha decreases in a left frontal electrode cluster from around 600 msec after stimulus onset. Successful encoding of semantic versus nonsemantic foils during a subsequent memory test was related to decreases in alpha oscillatory activity in the same left frontal electrode cluster, which emerged relatively late in the trial at around 1000-1600 msec after stimulus onset. Across participants, left frontal alpha power elicited by semantic processing during the study phase correlated significantly with left frontal alpha power associated with semantic foil encoding during the memory test. Furthermore, larger left frontal alpha power decreases elicited by semantic foil encoding during the memory test predicted better subsequent semantic foil recognition in an additional surprise foil memory test, although this effect did not reach significance. These findings indicate that constraining retrieval toward semantic information involves reimplementing semantic encoding operations that are mediated by alpha oscillations and that such reimplementation occurs at a late stage of memory retrieval, perhaps reflecting additional monitoring processes.

Organic-inorganic hybrid optical foils with strong visible reflection, excellent near infrared-shielding ability and high transparency

NASA Astrophysics Data System (ADS)

Zhou, Yijie; Huang, Aibin; Zhou, Huaijuan; Ji, Shidong; Jin, Ping

2018-03-01

Research on functional flexible films has recently been attracting widespread attention especially with regards to foils, which can be designed artificially on the basis of the practical requirements. In this work, a foil with high visible reflection and a strong near infrared shielding efficiency was prepared by a simple wet chemical method. In the process of making this kind of optical foil, emulsion polymerization was first introduced to synthesize polymer opals, which were further compressed between two pieces of polyethylene terephthalate (PET) foil under polymer melting temperature to obtain a photonic crystal film with a strong reflection in the visible region to block blue rays. The following step was to coat a layer of the inorganic nano paint, which was synthesized by dispersing Cs-doped WO3 (CWO) nanoparticles homogenously into organic resin on the surface of the PET to achieve a high near infrared shielding ability. The final composite foil exhibited unique optical properties such as high visible reflectance (23.9%) to block blue rays, and excellent near infrared shielding efficiency (98.0%), meanwhile it still maintained a high transparency meaning that this foil could potentially be applied in energy-saving window films. To sum up, this study provides new insight into devising flexible hybrid films with novel optical properties, which could be further extended to prepare other optical films for potential use in automobile, architectural and other decorative fields.

Cycle performance testing of nonazeotropic mixtures of HFC-142A/HCFC-124 and HFC-32/HCFC-124 with enhanced surface heat exchangers

NASA Astrophysics Data System (ADS)

Vineyard, E. A.; Conklin, J. C.; Brown, A. J.

In an effort to improve the efficiency of residential heat pumps using alternative refrigerants, two nonazeotropic refrigerant mixtures (NARM's) were tested over a range of heat exchanger capacities to determine their cooling mode performance at US Department of Energy (DOE) heat pump rating conditions of 82 F (27.8 C). The two mixtures, 30% HFC-32/70% HCFC-124 and 75% HFC-143a/25% HCFC-124, were selected on the basis of a previous study that screened refrigerant pairs using such factors as boiling point, stability, ozone depletion potential (ODP), and coefficient of performance (COP) to determine suitable candidates for residential heat pump performance. Three refrigerant-side heat transfer enhancements were tested to determine improvements to overall system performance. Comparisons were made on the basis of the COP as a function of capacity. The results for one of the heat exchanger combinations, a segmented evaporator and finned condenser, were quite promising. Improvements in COP, relative to that for HCFC-22, were from 9 to 17% for the 30% HFC-32/70% HCFC-124 mixture and from 5 to 9% for the 75% HFC-143a/25% HCFC-124 NARM. Another combination, a smooth tube evaporator with a perforated foil insert and finned condenser, had similar gains at low capacities but experienced decreased performance at the higher capacities. The final combination, a smooth tube evaporator with a perforated foil insert and smooth tube condenser with a bent tab insert resulted in poor performance.

Nanocontainers made of Various Materials with Tunable Shape and Size

NASA Astrophysics Data System (ADS)

Zhao, Xianglong; Meng, Guowen; Han, Fangming; Li, Xiangdong; Chen, Bensong; Xu, Qiaoling; Zhu, Xiaoguang; Chu, Zhaoqin; Kong, Mingguang; Huang, Qing

2013-07-01

Nanocontainers have great potentials in targeted drug delivery and nanospace-confined reactions. However, the previous synthetic approaches exhibited limited control over the morphology, size and materials of the nanocontainers, which are crucial in practical applications. Here, we present a synthetic approach to multi-segment linear-shaped nanopores with pre-designed morphologies inside anodic aluminium oxide (AAO), by tailoring the anodizing duration after a rational increase of the applied anodizing voltage and the number of voltage increase during Al foil anodization. Then, we achieve nanocontainers with designed morphologies, such as nanofunnels, nanobottles, nano-separating-funnels and nanodroppers, with tunable sizes and diverse materials of carbon, silicon, germanium, hafnium oxide, silica and nickel/carbon magnetic composite, by depositing a thin layer of materials on the inner walls of the pre-designed AAO nanopores. The strategy has far-reaching implications in the designing and large-scale fabrication of nanocontainers, opening up new opportunities in nanotechnology applications.

Nanocontainers made of Various Materials with Tunable Shape and Size

PubMed Central

Zhao, Xianglong; Meng, Guowen; Han, Fangming; Li, Xiangdong; Chen, Bensong; Xu, Qiaoling; Zhu, Xiaoguang; Chu, Zhaoqin; Kong, Mingguang; Huang, Qing

2013-01-01

Nanocontainers have great potentials in targeted drug delivery and nanospace-confined reactions. However, the previous synthetic approaches exhibited limited control over the morphology, size and materials of the nanocontainers, which are crucial in practical applications. Here, we present a synthetic approach to multi-segment linear-shaped nanopores with pre-designed morphologies inside anodic aluminium oxide (AAO), by tailoring the anodizing duration after a rational increase of the applied anodizing voltage and the number of voltage increase during Al foil anodization. Then, we achieve nanocontainers with designed morphologies, such as nanofunnels, nanobottles, nano-separating-funnels and nanodroppers, with tunable sizes and diverse materials of carbon, silicon, germanium, hafnium oxide, silica and nickel/carbon magnetic composite, by depositing a thin layer of materials on the inner walls of the pre-designed AAO nanopores. The strategy has far-reaching implications in the designing and large-scale fabrication of nanocontainers, opening up new opportunities in nanotechnology applications. PMID:23867836

Block copolymer with simultaneous electric and ionic conduction for use in lithium ion batteries

DOEpatents

Javier, Anna Esmeralda K; Balsara, Nitash Pervez; Patel, Shrayesh Naran; Hallinan, Jr., Daniel T

2013-10-08

Redox reactions that occur at the electrodes of batteries require transport of both ions and electrons to the active centers. Reported is the synthesis of a block copolymer that exhibits simultaneous electronic and ionic conduction. A combination of Grignard metathesis polymerization and click reaction was used successively to synthesize the block copolymer containing regioregular poly(3-hexylthiophene) (P3HT) and poly(ethylene oxide) (PEO) segments. The P3HT-PEO/LiTFSI mixture was then used to make a lithium battery cathode with LiFePO.sub.4 as the only other component. All-solid lithium batteries of the cathode described above, a solid electrolyte and a lithium foil as the anode showed capacities within experimental error of the theoretical capacity of the battery. The ability of P3HT-PEO to serve all of the transport and binding functions required in a lithium battery electrode is thus demonstrated.

Cutting of Gold Foil in the Genesis Laboratory

NASA Image and Video Library

2005-02-15

The facility for storing and examining Genesis solar wind samples consists of two adjacent laboratories. In these laboratories, the cutting of gold foil to be used in the gathering of the solar wind dust aboard the Genesis spacecraft. Views include: The process of cutting gold foil to be used aboard the Genesis spacecraft. The technicians use Gore-Tex suits with filters as to not contaminate the items.

Theoretical performance of foil journal bearings

NASA Technical Reports Server (NTRS)

Carpino, M.; Peng, J.-P.

1991-01-01

A modified forward iteration approach for the coupled solution of foil bearings is presented. The method is used to predict the steady state theoretical performance of a journal type gas bearing constructed from an inextensible shell supported by an elastic foundation. Bending effects are treated as negligible. Finite element methods are used to predict both the foil deflections and the pressure distribution in the gas film.

The head problem. The organizational significance of segmentation in head development.

PubMed

Horder, Tim J; Presley, Robert; Slípka, Jaroslav

2010-01-01

This review argues for the segmental basis of chordate head organization which, like somite-based segmental organization in the trunk, takes its origin from early mesodermal development. The review builds on, and brings up to date, Goodrich's well-known scheme of head organization. It surveys recent data in support of this scheme and shows how evidence and arguments supposedly in conflict with it can be accommodated. Many of the arguments revolve around matters of methodology; the limitations of older LM, SEM (on which the concept of "somitomeres" is based) and recent molecular evidence (which has sometimes been seen as allocating the central role in head organization to the CNS and the neural crest) are highlighted and shown to explain a number of claims contrary to Goodrich's. We provide (in Part 2) a new, comparative survey of the best available evidence most directly relevant to the Goodrich Bauplan, with a special emphasis on stem chordates. The postotic region has commonly been seen as segmentally organized: the critical issues concern the preotic region. There are many reasons why Goodrich's three preotic segments may become specialized during evolution and why the underlying initial segmental organization may be overridden in later stages during embryonic development; we refer to a number of these. We conclude that the preotic segmental Bauplan is remarkably conserved and most explicitly demonstrated among stem forms, but we also suggest that the concept of the prechordal plate requires careful reexamination. Central to our overall analysis is the importance of the epigenetic nature of embryogenesis; its implications are made clear. Finally we speculate on evolutionary implications for the origin of the head and its specialized features. The review is intended to serve as a resource giving access to references to a wealth of now neglected, older data on anamniote embryology.

Structure, wettability and thermal degradation of new fluoro-oligomer modified nanoclays.

PubMed

Valsecchi, R; Viganò, M; Levi, M; Turri, S

2008-04-01

Quaternary ammonium salts based on monofunctionalized Perfluoropolyether (PFPE) oligomers were synthesized and used for the cation exchange process of sodium Montmorillonite nanoclays. The new fluoromodified nanoclays were characterized through X-rays diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), termogravimetric analysis (TGA), differential scanning calorimetry (DSC), electronic microscopy (SEM-EDS), and contact angle measurements (CA). In particular XRD showed rather complex patterns (presence of higher order reflections) which allowed the calculation of basal spacings, regularly increasing with the molecular weight of the fluorinated macrocation. Both IR and SEM confirmed the presence of fluorinated segments at clays interface, while TGA showed a limited thermal stability with an onset of degradation temperature which seems not dependent on the molecular weight of the macrocation. CA measurements showed a peculiar behaviour, with evident dynamic hysteresis phenomena and surface tension components quite different from those of commercially available, organomodified clays.

Generation and Characterization of Nanoaerosols Using a Portable Scanning Mobility Particle Sizer and Electron Microscopy

NASA Astrophysics Data System (ADS)

Marty, Adam J.

The purpose of this research is to demonstrate the ability to generate and characterize a nanometer sized aerosol using solutions, suspensions, and a bulk nanopowder, and to research the viability of using an acoustic dry aerosol generator/elutriator (ADAGE) to aerosolize a bulk nanopowder into a nanometer sized aerosol. The research compares the results from a portable scanning mobility particle sizer (SMPS) to the more traditional method of counting and sizing particles on a filter sample using scanning electron microscopy (SEM). Sodium chloride aerosol was used for the comparisons. The sputter coating thickness, a conductive coating necessary for SEM, was measured on different sizes of polystyrene latex spheres (PSLS). Aluminum oxide powder was aerosolized using an ADAGE and several different support membranes and sound frequency combinations were explored. A portable SMPS was used to determine the size distributions of the generated aerosols. Polycarbonate membrane (PCM) filter samples were collected for subsequent SEM analysis. The particle size distributions were determined from photographs of the membrane filters. SMPS data and membrane samples were collected simultaneously. The sputter coating thicknesses on four different sizes of PSLS, range 57 nanometers (nm) to 220 nm, were measured using transmission electron microscopy and the results from the SEM and SMPS were compared after accounting for the sputter coating thickness. Aluminum oxide nanopowder (20 nm) was aerosolized using a modified ADAGE technique. Four different support membranes and four different sound frequencies were tested with the ADAGE. The aerosol was collected onto PCM filters and the samples were examined using SEM. The results indicate that the SMPS and SEM distributions were log-normally distributed with a median diameter of approximately 42 nm and 55 nm, respectively, and geometric standard deviations (GSD) of approximately 1.6 and 1.7, respectively. The two methods yielded similar distributional trends with a difference in median diameters of approximately 11 -- 15 nm. The sputter coating thickness on the different sizes of PSLSs ranged from 15.4 -- 17.4 nm. The aerosols generated, using the modified ADAGE, were low in concentration. The particles remained as agglomerates and varied widely in size. An aluminum foil support membrane coupled with a high sound frequency generated the smallest agglomerates. A well characterized sodium chloride aerosol was generated and was reproducible. The distributions determined using SEM were slightly larger than those obtained from SMPS, however, the distributions had relatively the same shape as reflected in their GSDs. This suggests that a portable SMPS is a suitable method for characterizing a nanoaerosol. The sizing techniques could be compared after correcting for the effects of the sputter coating necessary for SEM examination. It was determined that the sputter coating thickness on nano-sized particles and particles up to approximately 220 nm can be expected to be the same and that the sputter coating can add considerably to the size of a nanoparticle. This has important implications for worker health where nanoaerosol exposure is a concern. The sputter coating must be considered when SEM is used to describe a nanoaerosol exposure. The performance of the modified ADAGE was less than expected. The low aerosol output from the ADAGE prevented a more detailed analysis and was limited to only a qualitative comparison. Some combinations of support membranes and sound frequencies performed better than others, particularly conductive support membranes and high sound frequencies. In conclusion, a portable SMPS yielded results similar to those obtained by SEM. The sputter coating was the same thickness on the PSLSs studied. The sputter coating thickness must be considered when characterizing nanoparticles using SEM. Finally, a conductive support membrane and higher frequencies appeared to generate the smallest agglomerates using the ADAGE technique.

Metallic glass coating on metals plate by adjusted explosive welding technique

NASA Astrophysics Data System (ADS)

Liu, W. D.; Liu, K. X.; Chen, Q. Y.; Wang, J. T.; Yan, H. H.; Li, X. J.

2009-09-01

Using an adjusted explosive welding technique, an aluminum plate has been coated by a Fe-based metallic glass foil in this work. Scanning electronic micrographs reveal a defect-free metallurgical bonding between the Fe-based metallic glass foil and the aluminum plate. Experimental evidence indicates that the Fe-based metallic glass foil almost retains its amorphous state and mechanical properties after the explosive welding process. Additionally, the detailed explosive welding process has been simulated by a self-developed hydro-code and the bonding mechanism has been investigated by numerical analysis. The successful welding between the Fe-based metallic glass foil and the aluminum plate provides a new way to obtain amorphous coating on general metal substrates.

Development of explosively bonded TZM wire reinforced Columbian sheet composites

NASA Technical Reports Server (NTRS)

Otto, H. E.; Carpenter, S. H.

1972-01-01

Methods of producing TZM molybdenum wire reinforced C129Y columbium alloy composites by explosive welding were studied. Layers of TZM molybdenum wire were wound on frames with alternate layers of C129Y columbium alloy foil between the wire layers. The frames held both the wire and foils in place for the explosive bonding process. A goal of 33 volume percent molybdenum wire was achieved for some of the composites. Variables included wire diameter, foil thickness, wire separation, standoff distance between foils and types and amounts of explosive. The program was divided into two phases: (1) development of basic welding parameters using 5 x 10-inch composites, and (2) scaleup to 10 x 20-inch composites.

Electric fields, electron production, and electron motion at the stripper foil in the Los Alamos Proton Storage Ring

NASA Astrophysics Data System (ADS)

Plum, M.

The beam instability at the Los Alamos Proton Storage Ring (PSR) most likely involves coupled oscillations between electrons and protons. For this instability to occur, there must be a strong source of electrons. Investigation of the various sources of electrons in the PSR had begun. Copious electron production is expected in the injection section because this section contains the stripper foil. This foil is mounted near the center of the beam pipe, and both circulating and injected protons pass through it, thus allowing ample opportunity for electron production. This paper discusses various mechanisms for electron production, beam-induced electric fields, and electron motion in the vicinity of the foil.

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.

Use of Kelvin probe force microscopy for identification of CVD grown graphene flakes on copper foil

NASA Astrophysics Data System (ADS)

Kumar, Rakesh; Mehta, B. R.; Kanjilal, D.

2017-05-01

Graphene flakes have been grown by chemical vapour deposition (CVD) method on Cu foils. The obtained graphene flakes have been characterized by optical microscopy, field emission scanning electron microscopy, Kelvin probe force microscopy (KPFM) and Raman spectroscopy. The graphene flakes grown on Cu foil comprise mainly single layer graphene and confirm that the nucleation for graphene growth starts very quickly. Moreover, KPFM has been found to be a valuable technique to differentiate between covered and uncovered portion of Cu foil by graphene flakes deposited for shorter duration. The results show that KPFM can be a very useful technique in understanding the mechanism of graphene growth.

All-inorganic large-area low-cost and durable flexible perovskite solar cells using copper foil as a substrate.

PubMed

Abdollahi Nejand, B; Nazari, P; Gharibzadeh, S; Ahmadi, V; Moshaii, A

2017-01-05

Here, a low-cost perovskite solar cell using CuI and ZnO as the respective inorganic hole and electron transport layers is introduced. Copper foil is chosen as a cheap and low-weight conductive substrate which has a similar work function to ITO. Besides, copper foil is an interesting copper atom source for the growth of the upper cuprous iodide layer on copper foil. A spray coating of a transparent silver nanowire electrode is used as a top contact. The prepared device shows a maximum power conversion efficiency of 12.80% and long-term durability providing an environmentally and market friendly perovskite solar cell.

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. Copyright © 2015 Elsevier Ltd. All rights reserved.

Dye Foils With Increased Durability For Passive Q-Switching In A 1064 Nm Laser.

NASA Astrophysics Data System (ADS)

Mierczyk, Z.; Kwasny, M.; Czeszko, J.

1987-10-01

The results of spectral (IR, UV-VIS, H NMR) , gel permeation chromatography and differential thermal analysis investigations of structures of dye foils consisting of bis-(4-dimethyl-amino-dithio-benzil)-nickel dye suspended in polymethylmethacrylate matrix, to be used for passive Q-switching in a 1064 nm laser, are reported. Results of experimental measurements and of numerical calculations of thermal and generating properties, and of the endurance of passive foil type Q-switches in the resona-tor of YAG:Nd3+ laser are also presented. Optimization of polymerization conditions has enabled the production of dye foils with high thermal and photochemical resistance, which give stable operation of a giant pulsed laser.

Effects of laser shock peening with contacting foil on micro laser texturing surface of Ti6Al4V

NASA Astrophysics Data System (ADS)

Dai, Fengze; Zhang, Zidong; Ren, Xudong; Lu, Jinzhong; Huang, Shu

2018-02-01

Ti6Al4V samples with micro-dimple arrays were subjected to laser shock peening in contact with foil (HCLSP). The surface roughness, micro-hardness, the residual stress distribution and the surface morphology of the micro-dimple arrays were studied to evaluate the effects of HCLSP. Moreover, the surface topography of the foils in contact was also analyzed. The gap existence between the foil and the to-be treated surface led the mechanism of HCLSP to be different compared to regular laser shock peening. The surface roughness reduction, the work-hardening effects, the compressive residual stress and the micro crack enclosure were achieved. A simplified ball-hitting-surface model was utilized to analyze the HCLSP impact. The model could well explain the experimental results. When treated by the HCLSP with H62 foil at the laser power density of 4.24 GW/cm2, the Ti6Al4V samples with micro-dimple arrays exhibit well surface topography and mechanical performance.

Liquid Oxygen Rotating Friction Ignition Testing of Aluminum and Titanium with Monel and Inconel for Rocket Engine Propulsion System Contamination Investigation

NASA Technical Reports Server (NTRS)

Peralta, S.; Rosales, Keisa R.; Stoltzfus, Joel M.

2009-01-01

Metallic contaminant was found in the liquid oxygen (LOX) pre-valve screen of the shuttle main engine propulsion system on two orbiter vehicles. To investigate the potential for an ignition, NASA Johnson Space Center White Sands Test Facility performed (modified) rotating friction ignition testing in LOX. This testing simulated a contaminant particle in the low-pressure oxygen turbo pump (LPOTP) and the high-pressure oxygen turbo pump (HPOTP) of the shuttle main propulsion system. Monel(R) K-500 and Inconel(R) 718 samples represented the LPOTP and HPOTP materials. Aluminum foil tape and titanium foil represented the contaminant particles. In both the Monel(R) and Inconel(R) material configurations, the aluminum foil tape samples did not ignite after 30 s of rubbing. In contrast, all of the titanium foil samples ignited regardless of the rubbing duration or material configuration. However, the titanium foil ignitions did not propagate to the Monel and Inconel materials.

Evidence of circular Rydberg states in beam-foil experiments: Role of the surface wake field

NASA Astrophysics Data System (ADS)

Sharma, Gaurav; Puri, Nitin K.; Kumar, Pravin; Nandi, T.

2017-12-01

We have employed the concept of the surface wake field to model the formation of the circular Rydberg states in the beam-foil experiments. The experimental studies of atomic excitation processes show the formation of circular Rydberg states either in the bulk of the foil or at the exit surface, and the mechanism is explained by several controversial theories. The present model is based on the interesting fact that the charge state fraction as well as the surface wake field depend on the foil thickness and it resolves a long-standing discrepancy on the mechanism of the formation of circular Rydberg states. The influence of exit layers is twofold. Initially, the high angular momentum Rydberg states are produced in the last layers of the foil by the Stark switching due to the bulk wake field and finally, they are transferred to the circular Rydberg states as a single multiphoton process due to the influence of the surface wake field.

LANL Experience Rolling Zr-Clad LEU-10Mo Foils for AFIP-7

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hammon, Duncan L.; Clarke, Kester D.; Alexander, David J.

2015-05-29

The cleaning, canning, rolling and final trimming of Low Enriched Uranium-10 wt. pct. Molybdenum (LEU-10Mo) foils for ATR (Advanced Test Reactor) fuel plates to be used in the AFIP-7 (ATR Full Size Plate In Center Flux Trap Position) experiments are summarized. Six Zr-clad foils were produced from two LEU-10Mo castings supplied to Los Alamos National Laboratory (LANL) by Y-12 National Security Complex. Details of cleaning and canning procedures are provided. Hot- and cold-rolling results are presented, including rolling schedules, images of foils in-process, metallography and local compositions of regions of interest, and details of final foil dimensions and process yield.more » This report was compiled from the slides for the presentation of the same name given by Duncan Hammon on May 12, 2011 at the AFIP-7 Lessons Learned meeting in Salt Lake City, UT, with Los Alamos National Laboratory document number LA-UR 11-02898.« less

Piezoelectric characterization of Pb(Zr,Ti)O3 thin films deposited on metal foil substrates by dip coating

NASA Astrophysics Data System (ADS)

Hida, Hirotaka; Hamamura, Tomohiro; Nishi, Takahito; Tan, Goon; Umegaki, Toshihito; Kanno, Isaku

2017-10-01

We fabricated the piezoelectric bimorphs composed of Pb(Zr,Ti)O3 (PZT) thin films on metal foil substrates. To efficiently inexpensively manufacture piezoelectric bimorphs with high flexibility, 1.2-µm-thick PZT thin films were directly deposited on both surfaces of 10- and 20-µm-thick bare stainless-steel (SS) foil substrates by dip coating with a sol-gel solution. We confirmed that the PZT thin films deposited on the SS foil substrates at 500 °C or above have polycrystalline perovskite structures and the measured relative dielectric constant and dielectric loss were 323-420 and 0.12-0.17, respectively. The PZT bimorphs were demonstrated by comparing the displacements of the cantilever specimens driven by single- and double-side PZT thin films on the SS foil substrates under the same applied voltage. We characterized the piezoelectric properties of the PZT bimorphs and the calculated their piezoelectric coefficient |e 31,f| to be 0.3-0.7 C/m2.

Multilayer based lab-on-a-chip-systems for substance testing

NASA Astrophysics Data System (ADS)

Sonntag, Frank; Grünzner, Stefan; Schmieder, Florian; Busek, Mathias; Klotzbach, Udo; Franke, Volker

2015-03-01

An integrated technology chain for laser-microstructuring and bonding of polymer foils for fast, flexible and low-cost manufacturing of multilayer lab-on-a-chip devices especially for complex cell and tissue culture applications, which provides pulsatile fluid flow within physiological ranges at low media-to-cells ratio, was developed and established. Initially the microfluidic system is constructively divided into individual layers which are formed by separate foils or plates. Based on the functional boundary conditions and the necessary properties of each layer the corresponding foils and plates are chosen. In the third step the foils and plates are laser microstructured and functionalized from both sides. In the fourth and last manufacturing step the multiple plates and foils are joined using thermal diffusion bonding. Membranes for pneumatically driven valves and micropumps where bonded via chemical surface modification. Based on the established lab-on-a-chip platform for perfused cell-based assays, a multilayer microfluidic system with two parallel connected cell culture chambers was successfully implemented.

The dynamic characteristics of a turbo-rotor simulator supported on gas-lubricated foil bearings. Part 1: Response to rotating imbalance and unidirectional excitation

NASA Technical Reports Server (NTRS)

Licht, L.

1970-01-01

A sixteen-inch rotor, weighing approximately twenty-one pounds, was supported by air-lubricated foil bearings. In physical size and in mass distribution, the rotor closely matched that of an experimental Brayton cycle turboalternator unit. The rotor was stable in both vertical horizontal attitudes at speeds up to 50,000 rpm. A detailed description of the experimental apparatus and of the foil bearing design are given. The paper contains data on response of the rotor to rotating imbalance, symmetric and asymmetric, and to excitation by means of a vibrator (shake table). It is concluded that the gas-lubricated foil bearing suspension is free from fractional frequency whirl and suffers no loss of load capacity when excited at frequency equal to half the rotational speed. In contrast to rigid gas bearings, the foil bearing imposes no stringent requirements with respect to dimensional tolerances, cleanliness, or limitations of journal motion within the narrow confines of bearing clearance.

THE USE OF A PHOSPHORUS-POLYTHENE MIXTURE FOR FAST NEUTRON MEASUREMENTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stephens, K.G.; Williams, G.H.

1962-06-01

A convenient way of measuring relative fast fluxes in a small reactor core using foils of phosphorus-Polythene mixture is described. Determination of the disintegration rate of these foils involves the measurement of the BETA -ray self-absorption of the foils as a function of thickness. Accurate disintegration rate measurements after irradiation for 6 hr using 7/16 in. dia foils enabled fission fluxes of 5 x 10/sup 5/ n/cm/sup 2/ sec or more to be measured absolutely to within plus or minus 6 per cent and fluxes as low as 5 x 10/sup 4/ n/cm/sup 2/ sec to within plus or minusmore » 20 per cent when the counter background was 80 c/ min. By reducing this background and increasing foil size, both of these limits are lowered by about a factor 50. The method compares favorably with methods using the S/sup 32/(n,p P/sup 32/ threshold reaction. (auth)« less

Dynamic environmental control mechanisms for pneumatic foil constructions

NASA Astrophysics Data System (ADS)

Flor, Jan-Frederik; Wu, Yupeng; Beccarelli, Paolo; Chilton, John

2017-11-01

Membrane and foil structures have become over the last decades an attractive alternative to conventional materials and building systems with increasing implementation in different typologies and scale. The development of transparent, light, flexible and resistant materials like Ethylene Tetrafluoroethylene (ETFE) has triggered a rethinking of the building envelope in the building industry towards lightweight systems. ETFE foil cushions have proven to fulfil the design requirements in terms of structural efficiency and aesthetic values. But the strategies to satisfy increasing demands of energy efficiency and comfort conditions are still under development. The prediction and manipulation of the thermo-optical behaviour of ETFE foil cushion structures currently remain as one of the main challenges for designers and manufacturers. This paper reviews ongoing research regarding the control of the thermo-optical performance of ETFE cushion structures and highlights challenges and possible improvements. An overview of different dynamic and responsive environmental control mechanisms for multilayer foil constructions is provided and the state of the art in building application outlined by the discussion of case studies.

Accelerated eruption of rat lower incisor. Relationship between impeded and unimpeded eruption rates, rate of attrition, tooth length, and production of dentin and enamel.

PubMed

Risnes, S; Septier, D; Goldberg, M

1995-01-01

The present investigation studies the effects of persistently cutting one lower rat incisor out of occlusion. Within four days, the rate of eruption of the cut (unimpeded) incisor increased to 216% and that of the uncut (impeded) contralateral to 136% of the baseline rate. While the former remained high, the latter decreased gradually to about 90% within three weeks. The rate of attrition of the impeded incisor increased to 233% of the baseline rate within two days, then fell abruptly, and remained at a slightly lower level than the rate of eruption. Accordingly, the length of the erupted part of the impeded incisor decreased initially, but increased gradually after about four days. Measurements made on SEM micrographs of the series of transverse tooth segments obtained when cutting the incisor out of occlusion, showed that growth-related increase in mesiodistal tooth width was arrested from the 10th segment, dentin thickness decreased gradually to about 50% in the 12th segment, and enamel thickness, after an initial increase, decreased to about 80% in the 11th segment. The present study provides experimental evidence that accelerated eruption affects morphogenesis and histogenesis of the rat lower incisor. An impeded incisor, especially the contralateral, may not serve as an ideal control.

Bi-metal foil gas dynamic bearings with bimorph piezoelectric foils

NASA Astrophysics Data System (ADS)

Sytin, A.; Rodichev, A.; Kulkov, A.

2017-08-01

The present paper considers application of bi-metal materials and coatings to provide necessary strength and wear resistance of the surfaces of rigid and elastic gas dynamic bearings. Authors suggest using multi-layer foils with bimorph piezoelectric elements that operate in the generator regime to determine the deformation of elastic elements, and in the actuator regime to form an optimal shape of the surface of the bearing.

Ventrolateral prefrontal cortex and the effects of task demand context on facial affect appraisal in schizophrenia.

PubMed

Leitman, David I; Wolf, Daniel H; Loughead, James; Valdez, Jeffrey N; Kohler, Christian G; Brensinger, Colleen; Elliott, Mark A; Turetsky, Bruce I; Gur, Raquel E; Gur, Ruben C

2011-01-01

Schizophrenia patients display impaired performance and brain activity during facial affect recognition. These impairments may reflect stimulus-driven perceptual decrements and evaluative processing abnormalities. We differentiated these two processes by contrasting responses to identical stimuli presented under different contexts. Seventeen healthy controls and 16 schizophrenia patients performed an fMRI facial affect detection task. Subjects identified an affective target presented amongst foils of differing emotions. We hypothesized that targeting affiliative emotions (happiness, sadness) would create a task demand context distinct from that generated when targeting threat emotions (anger, fear). We compared affiliative foil stimuli within a congruent affiliative context with identical stimuli presented in an incongruent threat context. Threat foils were analysed in the same manner. Controls activated right orbitofrontal cortex (OFC)/ventrolateral prefrontal cortex (VLPFC) more to affiliative foils in threat contexts than to identical stimuli within affiliative contexts. Patients displayed reduced OFC/VLPFC activation to all foils, and no activation modulation by context. This lack of context modulation coincided with a 2-fold decrement in foil detection efficiency. Task demands produce contextual effects during facial affective processing in regions activated during affect evaluation. In schizophrenia, reduced modulation of OFC/VLPFC by context coupled with reduced behavioural efficiency suggests impaired ventral prefrontal control mechanisms that optimize affective appraisal.

Determination of integral cross sections of 3H in Al foils monitors irradiated by protons with energies ranging from 40 to 2600 MeV

NASA Astrophysics Data System (ADS)

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.

2016-05-01

The results of 3H production in Al foil monitors (˜ 59 mg/cm2 thickness) are presented. These foils have been irradiated 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. An ultra low level liquid scintillation spectrometer Quantulus1220 was used 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.

Uniaxial creep property and viscoelastic-plastic modelling of ethylene tetrafluoroethylene (ETFE) foil

NASA Astrophysics Data System (ADS)

Li, Yintang; Wu, Minger

2015-02-01

Ethylene tetrafluoroethylene (ETFE) foil has been widely used in spatial structures for its light weight and high transparency. This paper studies short- and long-term creep properties of ETFE foil. Two series of short-term creep and recovery tests were performed, in which residual strain was observed. A long-term creep test of ETFE foil was also conducted and lasted about 400 days. A viscoelastic-plastic model was then established to describe short-term creep and recovery behaviour of ETFE foil. This model contains a traditional generalised Kelvin part and an added steady-flow component to represent viscoelastic and viscoplastic behaviour, respectively. The model can fit tests' data well at three stresses and six temperatures. Additionally, time-temperature superposition was adopted to simulate long-term creep behaviour of ETFE foil. Horizontal shifting factors were determined by W.L.F. equation in which transition temperature was simulated by shifting factors. Using this equation, long-term creep behaviours at three temperatures were predicted. The results of the long-term creep test showed that a short-term creep test at identical temperatures was insufficient to predict additional creep behaviour, and the long-term creep test verified horizontal shifting factors which were derived from the time-temperature superposition.

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/cm 2 thickness) are presented. We irradiated these foils in 15×15 mm polyethylene bags of ~ 14 mg/cm 2 thickness together with foils of Cr (~ 395 mg/cm 2 thickness) and 56Fe (~ 332 mg/cm 2 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.more » 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.« less

The target-to-foils shift in simultaneous and sequential lineups.

PubMed

Clark, Steven E; Davey, Sherrie L

2005-04-01

A theoretical cornerstone in eyewitness identification research is the proposition that witnesses, in making decisions from standard simultaneous lineups, make relative judgments. The present research considers two sources of support for this proposal. An experiment by G. L. Wells (1993) showed that if the target is removed from a lineup, witnesses shift their responses to pick foils, rather than rejecting the lineups, a result we will term a target-to-foils shift. Additional empirical support is provided by results from sequential lineups which typically show higher accuracy than simultaneous lineups, presumably because of a decrease in the use of relative judgments in making identification decisions. The combination of these two lines of research suggests that the target-to-foils shift should be reduced in sequential lineups relative to simultaneous lineups. Results of two experiments showed an overall advantage for sequential lineups, but also showed a target-to-foils shift equal in size for simultaneous and sequential lineups. Additional analyses indicated that the target-to-foils shift in sequential lineups was moderated in part by an order effect and was produced with (Experiment 2) or without (Experiment 1) a shift in decision criterion. This complex pattern of results suggests that more work is needed to understand the processes which underlie decisions in simultaneous and sequential lineups.

Spectroscopic Measurements of Planar Foil Plasmas Driven by a MA LTD

NASA Astrophysics Data System (ADS)

Patel, Sonal; Yager-Elorriaga, David; Steiner, Adam; Jordan, Nick; Gilgenbach, Ronald; Lau, Y. Y.

2014-10-01

Planar foil ablation experiments are being conducted on the Linear Transformer Driver (LTD) at the University of Michigan. The experiment consists of a 400 nm-thick, Al planar foil and a current return post. An optical fiber is placed perpendicular to the magnetic field and linear polarizers are used to isolate the pi and sigma lines. The LTD is charged to +/-70 kV with approximately 400-500 kA passing through the foil. Laser shadowgraphy has previously imaged the plasma and measured anisotropy in the Magneto Rayleigh-Taylor (MRT) instability. Localized magnetic field measurements using Zeeman splitting during the current rise is expected to yield some insight into this anisotropy. Initial experiments use Na D lines of Al foils seeded with sodium to measure Zeeman splitting. Several ion lines are also currently being studied, such as Al III and C IV, to probe the higher temperature core plasma. In planned experiments, several lens-coupled optical fibers will be placed across the foil, and local magnetic field measurements will be taken to measure current division within the plasma. This work was supported by US DoE. S.G. Patel and A.M. Steiner supported by NPSC funded by Sandia. D.A. Yager supported by NSF fellowship Grant DGE 1256260.

Dynamics and locomotion of flexible foils in a frictional environment

NASA Astrophysics Data System (ADS)

Wang, Xiaolin; Alben, Silas

2018-01-01

Over the past few decades, oscillating flexible foils have been used to study the physics of organismal propulsion in different fluid environments. Here, we extend this work to a study of flexible foils in a frictional environment. When the foil is oscillated by heaving at one end but is not free to locomote, the dynamics change from periodic to non-periodic and chaotic as the heaving amplitude increases or the bending rigidity decreases. For friction coefficients lying in a certain range, the transition passes through a sequence of N-periodic and asymmetric states before reaching chaotic dynamics. Resonant peaks are damped and shifted by friction and large heaving amplitudes, leading to bistable states. When the foil is free to locomote, the horizontal motion smoothes the resonant behaviours. For moderate frictional coefficients, steady but slow locomotion is obtained. For large transverse friction and small tangential friction corresponding to wheeled snake robots, faster locomotion is obtained. Travelling wave motions arise spontaneously, and move with horizontal speeds that scale as transverse friction coefficient to the power 1/4 and input power that scales as the transverse friction coefficient to the power 5/12. These scalings are consistent with a boundary layer form of the solutions near the foil's leading edge.

Dynamics and locomotion of flexible foils in a frictional environment.

PubMed

Wang, Xiaolin; Alben, Silas

2018-01-01

Over the past few decades, oscillating flexible foils have been used to study the physics of organismal propulsion in different fluid environments. Here, we extend this work to a study of flexible foils in a frictional environment. When the foil is oscillated by heaving at one end but is not free to locomote, the dynamics change from periodic to non-periodic and chaotic as the heaving amplitude increases or the bending rigidity decreases. For friction coefficients lying in a certain range, the transition passes through a sequence of N -periodic and asymmetric states before reaching chaotic dynamics. Resonant peaks are damped and shifted by friction and large heaving amplitudes, leading to bistable states. When the foil is free to locomote, the horizontal motion smoothes the resonant behaviours. For moderate frictional coefficients, steady but slow locomotion is obtained. For large transverse friction and small tangential friction corresponding to wheeled snake robots, faster locomotion is obtained. Travelling wave motions arise spontaneously, and move with horizontal speeds that scale as transverse friction coefficient to the power 1/4 and input power that scales as the transverse friction coefficient to the power 5/12. These scalings are consistent with a boundary layer form of the solutions near the foil's leading edge.

Characterizing proton-activated materials to develop PET-mediated proton range verification markers

NASA Astrophysics Data System (ADS)

Cho, Jongmin; Ibbott, Geoffrey S.; Kerr, Matthew D.; Amos, Richard A.; Stingo, Francesco C.; Marom, Edith M.; Truong, Mylene T.; Palacio, Diana M.; Betancourt, Sonia L.; Erasmus, Jeremy J.; DeGroot, Patricia M.; Carter, Brett W.; Gladish, Gregory W.; Sabloff, Bradley S.; Benveniste, Marcelo F.; Godoy, Myrna C.; Patil, Shekhar; Sorensen, James; Mawlawi, Osama R.

2016-06-01

Conventional proton beam range verification using positron emission tomography (PET) relies on tissue activation alone and therefore requires particle therapy PET whose installation can represent a large financial burden for many centers. Previously, we showed the feasibility of developing patient implantable markers using high proton cross-section materials (18O, Cu, and 68Zn) for in vivo proton range verification using conventional PET scanners. In this technical note, we characterize those materials to test their usability in more clinically relevant conditions. Two phantoms made of low-density balsa wood (~0.1 g cm-3) and beef (~1.0 g cm-3) were embedded with Cu or 68Zn foils of several volumes (10-50 mm3). The metal foils were positioned at several depths in the dose fall-off region, which had been determined from our previous study. The phantoms were then irradiated with different proton doses (1-5 Gy). After irradiation, the phantoms with the embedded foils were moved to a diagnostic PET scanner and imaged. The acquired data were reconstructed with 20-40 min of scan time using various delay times (30-150 min) to determine the maximum contrast-to-noise ratio. The resultant PET/computed tomography (CT) fusion images of the activated foils were then examined and the foils’ PET signal strength/visibility was scored on a 5 point scale by 13 radiologists experienced in nuclear medicine. For both phantoms, the visibility of activated foils increased in proportion to the foil volume, dose, and PET scan time. A linear model was constructed with visibility scores as the response variable and all other factors (marker material, phantom material, dose, and PET scan time) as covariates. Using the linear model, volumes of foils that provided adequate visibility (score 3) were determined for each dose and PET scan time. The foil volumes that were determined will be used as a guideline in developing practical implantable markers.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Avery, S; Christodouleas, J; Delaney, 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 BBsmore » 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.« less

Initial Trial using Embedded Fibre Bragg Gratings for Distributed Strain Monitoring in a Shape Adaptive Composite Foil

DTIC Science & Technology

2012-02-01

available for interrogation. Although commercially available fibre Bragg grating ( FBG ) sensors have emerged in the marketplace over the past decade...the results from a preliminary trial investigating the feasibility of using embedded FBG arrays in a shape adaptive composite foil to characterise...The response from the FBG sensors was also monitored during fabrication of the foil during the resin infusion and curing stages of the process

Slowing down of 100 keV antiprotons in Al foils

NASA Astrophysics Data System (ADS)

Nordlund, K.

2018-03-01

Using energy degrading foils to slow down antiprotons is of interest for producing antihydrogen atoms. I consider here the slowing down of 100 keV antiprotons, that will be produced in the ELENA storage ring under construction at CERN, to energies below 10 keV. At these low energies, they are suitable for efficient antihydrogen production. I simulate the antihydrogen motion and slowing down in Al foils using a recently developed molecular dynamics approach. The results show that the optimal Al foil thickness for slowing down the antiprotons to below 5 keV is 910 nm, and to below 10 keV is 840 nm. Also the lateral spreading of the transmitted antiprotons is reported and the uncertainties discussed.

Radiation effects measurements on spacecraft electrostatic discharge tapes, thermal blankets and thermooptical coatings

NASA Technical Reports Server (NTRS)

Bouquet, F. L.; Hribar, V. F.; Metzler, E. C.; Russell, D. A.

1984-01-01

Selective results are presented of laboratory radiation tests of metallic foil tapes, thermal blankets, and thermooptical coatings undertaken as part of the development and qualification of materials for the Galileo spacecraft. Of the two metallic foil tapes used for electrical continuity, the adhesive used on the aluminum embossed foil was superior to the copper embossed foil when exposed to simulated Jovian electrons. Proton-irradiation tests performed on a number of thermal blanket samples showed that black polyester on Kapton proved to be a lower weight loss (i.e., outgassing) material than Fluorglas. In addition, preliminary results concerning the response of thermooptical coatings to simulated Jovian electrons show that the ITO-coated polyester over a Kapton surface gave the lowest absorptance.

Composite multilayer insulations for thermal protection of aerospace vehicles

NASA Technical Reports Server (NTRS)

Kourtides, Demetrius A.; Pitts, William C.

1989-01-01

Composite flexible multilayer insulation systems (MLI), consisting of alternating layers of metal foil and scrim cloth or insulation quilted together using ceramic thread, were evaluated for thermal performance and compared with a silica fibrous (baseline) insulation system. The systems studied included: (1) alternating layers of aluminoborosilicate (ABS) scrim cloth and stainless steel foil, with silica, ABS, or alumina insulation; (2) alternating layers of scrim cloth and aluminum foil, with silica or ABS insulation; (3) alternating layers of aluminum foil and silica or ABS insulation; and (4) alternating layers of aluminum-coated polyimide placed on the bottom of the silica insulation. The MLIs containing aluminum were the most efficient, measuring as little as half the backface temperature increase of the baseline system.

The effect of lineup member similarity on recognition accuracy in simultaneous and sequential lineups.

PubMed

Flowe, Heather D; Ebbesen, Ebbe B

2007-02-01

Two experiments investigated whether remembering is affected by the similarity of the study face relative to the alternatives in a lineup. In simultaneous and sequential lineups, choice rates and false alarms were larger in low compared to high similarity lineups, indicating criterion placement was affected by lineup similarity structure (Experiment 1). In Experiment 2, foil choices and similarity ranking data for target present lineups were compared to responses made when the target was removed from the lineup (only the 5 foils were presented). The results indicated that although foils were selected more often in target-removed lineups in the simultaneous compared to the sequential condition, responses shifted from the target to one of the foils at equal rates across lineup procedures.

Evaluation of bone formation in calcium phosphate scaffolds with μCT-method validation using SEM.

PubMed

Lewin, S; Barba, A; Persson, C; Franch, J; Ginebra, M-P; Öhman-Mägi, C

2017-10-05

There is a plethora of calcium phosphate (CaP) scaffolds used as synthetic substitutes to bone grafts. The scaffold performance is often evaluated from the quantity of bone formed within or in direct contact with the scaffold. Micro-computed tomography (μCT) allows three-dimensional evaluation of bone formation inside scaffolds. However, the almost identical x-ray attenuation of CaP and bone obtrude the separation of these phases in μCT images. Commonly, segmentation of bone in μCT images is based on gray scale intensity, with manually determined global thresholds. However, image analysis methods, and methods for manual thresholding in particular, lack standardization and may consequently suffer from subjectivity. The aim of the present study was to provide a methodological framework for addressing these issues. Bone formation in two types of CaP scaffold architectures (foamed and robocast), obtained from a larger animal study (a 12 week canine animal model) was evaluated by μCT. In addition, cross-sectional scanning electron microscopy (SEM) images were acquired as references to determine thresholds and to validate the result. μCT datasets were registered to the corresponding SEM reference. Global thresholds were then determined by quantitatively correlating the different area fractions in the μCT image, towards the area fractions in the corresponding SEM image. For comparison, area fractions were also quantified using global thresholds determined manually by two different approaches. In the validation the manually determined thresholds resulted in large average errors in area fraction (up to 17%), whereas for the evaluation using SEM references, the errors were estimated to be less than 3%. Furthermore, it was found that basing the thresholds on one single SEM reference gave lower errors than determining them manually. This study provides an objective, robust and less error prone method to determine global thresholds for the evaluation of bone formation in CaP scaffolds.

Effect of Substrates on the Photoelectrochemical Reduction of Water over Cathodically Electrodeposited p-Type Cu2O Thin Films.

PubMed

Shyamal, Sanjib; Hajra, Paramita; Mandal, Harahari; Singh, Jitendra Kumar; Satpati, Ashis Kumar; Pande, Surojit; Bhattacharya, Chinmoy

2015-08-26

In this study, we demonstrate development of p-Cu2O thin films through cathodic electrodeposition technique at constant current of 0.1 mA/cm(2) on Cu, Al, and indium tin oxide (ITO) substrates from basic CuSO4 solution containing Triton X-100 as the surfactant at 30-35 °C. The optical and morphological characterizations of the semiconductors have been carried out using UV-vis spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and Raman spectroscopy. The band gap energy of ∼2.1 eV is recorded, whereas SEM reveals that the surface morphology is covered with Cu2O semiconductors. XRD analyses confirm that with change in substrate, the size of Cu2O "cubic" crystallites decreases from ITO to Al to Cu substrates. Photoelectrochemical characterizations under dark and illuminated conditions have been carried out through linear sweep voltammetry, chronoamperometry and electrochemical impedance spectroscopic analysis. The photoelectrochemical reduction of water (H2O → H2) in pH 4.9 aqueous solutions over the different substrates vary in the order of Cu > Al > ITO. The highest current of 4.6 mA/cm(2) has been recorded over the Cu substrate even at a low illumination of 35 mW/cm(2), which is significantly higher than the values (2.4 mA/cm(2) on Au coated FTO or 4.07 mA/cm(2) on Cu foil substrate at an illumination of 100 mW/cm(2)) reported in literature.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miley, George H.

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 themore » 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 Facility (NIF) in CA within a year. This will usher in the technology development Phase of ICF after years of research aimed at achieving breakeven experiment. Methods to achieve the high energy gain needed for a competitive power plant will then be a key developmental issue, and our D-cluster target for Fast Ignition (FI) is expected to meet that need.« less

MULPEX: A compact multi-layered polymer foil collector for micrometeoroids and orbital debris

NASA Astrophysics Data System (ADS)

Kearsley, A. T.; Graham, G. A.; Burchell, M. J.; Taylor, E. A.; Drolshagen, G.; Chater, R. J.; McPhail, D.

Detailed studies of preserved hypervelocity impact residues on spacecraft multi-layer insulation foils have yielded important information about the flux of small particles from different sources in low-Earth orbit (LEO). We have extended our earlier research on impacts occurring in LEO to design and testing of a compact capture device. MUlti- Layer Polymer EXperiment (MULPEX) is simple, cheap to build, lightweight, of no power demand, easy to deploy, and optimised for the efficient collection of impact residue for analysis on return to Earth. The capture medium is a stack of very thin (8 and 40 μm) polyimide foils, supported on poly-tetrafluoroethylene sheet frames, surrounded by a protective aluminium casing. The uppermost foil has a very thin metallic coating for thermal protection and resistance to atomic oxygen and ultra-violet exposure. The casing provides a simple detachable interface for deployment on the spacecraft, facing into the desired direction for particle collection. On return to the laboratory, the stacked foils are separated for examination in a variable pressure scanning electron microscope, without need for surface coating. Analysis of impact residue is performed using energy dispersive X-ray spectrometers. Our laboratory experiments, utilising buck-shot firings of analogues to micrometeoroids (35-38 μm olivine) and space debris (4 μm alumina and 1 mm stainless steel) in a light gas gun, have shown that impact residue is abundant within the foil layers, and preserves a record of the impacting particle, whether of micrometer or millimetre dimensions. Penetrations of the top foil are easily recognised, and act as a proxy for dimensions of the penetrating particle. Impact may cause disruption and melting, but some residue retains sufficient crystallographic structure to show clear Raman lines, diagnostic of the original mineral.

MULPEX: a compact multi-layered polymer foil collector for micrometeoroids and orbital debris.

NASA Astrophysics Data System (ADS)

Kearsley, A. T.; Graham, G. A.; Burchell, M. J.; Taylor, E. A.; Drolshagen, G.; Chater, R. J.; McPhail, D.

Detailed studies of preserved hypervelocity impact residues on spacecraft multi-layer insulation foils have yielded important information about the flux of small particles from different sources in low-Earth orbit (LEO). We have extended our earlier research on impacts occurring in LEO to design and testing of a compact capture device. MULPEX (MUlti-Layer Polymer EXperiment) is simple, cheap to build, lightweight, of no power demand, easy to deploy, and optimised for the efficient collection of impact residue for analysis on return to Earth. The capture medium is a stack of very thin (8 micron and 40 micron) polyimide foils, supported on poly-tetrafluoroethylene sheet frames, surrounded by a protective aluminium casing. The uppermost foil has a very thin metallic coating for thermal protection and resistance to atomic oxygen and ultra-violet exposure. The casing provides a simple detachable interface for deployment on the spacecraft, facing into the desired direction for particle collection. On return to the laboratory, the stacked foils are separated for examination in a variable pressure scanning electron microscope, without need for surface coating. Analysis of impact residue is performed using energy dispersive X-ray spectrometers. Our laboratory experiments, utilising buck-shot firings of analogues to micrometeoroids (35-38 micron olivine) and space debris (4 micron alumina and 1mm stainless steel) in a light gas gun, have shown that impact residue is abundant within the foil layers, and preserves a record of the impacting particle, whether of micrometer or millimetre dimensions. Penetrations of the top foil are easily recognised, and act as a proxy for dimensions of the penetrating particle. Impact may cause disruption and melting, but some residue retains sufficient crystallographic structure to show clear Raman lines, diagnostic of the original mineral.

On the propagation mechanism of a detonation wave in a round tube with orifice plates

NASA Astrophysics Data System (ADS)

Ciccarelli, G.; Cross, M.

2016-09-01

This study deals with the investigation of the detonation propagation mechanism in a circular tube with orifice plates. Experiments were performed with hydrogen air in a 10-cm-inner-diameter tube with the second half of the tube filled with equally spaced orifice plates. A self-sustained Chapman-Jouguet (CJ) detonation wave was initiated in the smooth first half of the tube and transmitted into the orifice-plate-laden second half of the tube. The details of the propagation were obtained using the soot-foil technique. Two types of foils were used between obstacles, a wall-foil placed on the tube wall, and a flat-foil (sooted on both sides) placed horizontally across the diameter of the tube. When placed after the first orifice plate, the flat foil shows symmetric detonation wave diffraction and failure, while the wall foil shows re-initiation via multiple local hot spots created when the decoupled shock wave interacts with the tube wall. At the end of the tube, where the detonation propagated at an average velocity much lower than the theoretical CJ value, the detonation propagation is much more asymmetric with only a few hot spots on the tube wall leading to local detonation initiation. Consecutive foils also show that the detonation structure changes after each obstacle interaction. For a mixture near the detonation propagation limit, detonation re-initiation occurs at a single wall hot spot producing a patch of small detonation cells. The local overdriven detonation wave is short lived, but is sufficient to keep the global explosion front propagating. Results associated with the effect of orifice plate blockage and spacing on the detonation propagation mechanism are also presented.

Comparison of thermoregulatory devices used during anesthesia of C57BL/6 mice and correlations between body temperature and physiologic parameters.

PubMed

Caro, Adam C; Hankenson, F Claire; Marx, James O

2013-09-01

General anesthesia affects several body systems, including thermoregulation. Decreased body temperature during anesthesia has potential negative effects, including delayed recovery to consciousness. Thermoregulatory support devices are used to maintain temperature in anesthetized rodents. We analyzed 2 novel thermoregulatory devices, thermogenic gel packs and reflective foils, to compare their effectiveness in maintaining temperatures with that of a standard circulating-warm-water blanket (CWWB) in C57BL/6 mice. Mice were grouped randomly: control (no thermal support), reflective foil, gel pack, gel pack plus reflective foil, CWWB on medium setting, CWWB on high setting, and CWWB on high setting plus reflective foil. Mice were anesthetized with isoflurane for 30 min, and temperature and heart and respiratory rates were monitored. Results indicated that the temperatures of mice with reflective foil only (start temperature, 36.2 ± 0.38 °C; end temperature, 28.8 ± 0.78 °C) did not differ significantly from those of control mice; however, the inclusion of foil heightened thermogenic properties when combined with other devices. Thermogenic gel packs and CWWB on high setting, both with and without reflective foil, caused significant temperature increases (that is, 1.6 °C to 4.4 °C) in mice. CWWB on medium setting (blanket temperature, 37.5 °C) maintained mice at temperatures within 1 °C of the 36.1 °C baseline. Strong correlations existed between temperature, heart and respiratory rates, and recovery time to consciousness. This information provides guidance regarding the use of thermoregulatory devices in anesthetized rodents and demonstrates the effect of maintaining a consistent core temperature on physiologic parameters.

Comparison of Thermoregulatory Devices Used during Anesthesia of C57BL/6 Mice and Correlations between Body Temperature and Physiologic Parameters

PubMed Central

Caro, Adam C; Hankenson, F Claire; Marx, James O

2013-01-01

General anesthesia affects several body systems, including thermoregulation. Decreased body temperature during anesthesia has potential negative effects, including delayed recovery to consciousness. Thermoregulatory support devices are used to maintain temperature in anesthetized rodents. We analyzed 2 novel thermoregulatory devices, thermogenic gel packs and reflective foils, to compare their effectiveness in maintaining temperatures with that of a standard circulating-warm–water blanket (CWWB) in C57BL/6 mice. Mice were grouped randomly: control (no thermal support), reflective foil, gel pack, gel pack plus reflective foil, CWWB on medium setting, CWWB on high setting, and CWWB on high setting plus reflective foil. Mice were anesthetized with isoflurane for 30 min, and temperature and heart and respiratory rates were monitored. Results indicated that the temperatures of mice with reflective foil only (start temperature, 36.2 ± 0.38 °C; end temperature, 28.8 ± 0.78 °C) did not differ significantly from those of control mice; however, the inclusion of foil heightened thermogenic properties when combined with other devices. Thermogenic gel packs and CWWB on high setting, both with and without reflective foil, caused significant temperature increases (that is, 1.6 °C to 4.4 °C) in mice. CWWB on medium setting (blanket temperature, 37.5 °C) maintained mice at temperatures within 1 °C of the 36.1 °C baseline. Strong correlations existed between temperature, heart and respiratory rates, and recovery time to consciousness. This information provides guidance regarding the use of thermoregulatory devices in anesthetized rodents and demonstrates the effect of maintaining a consistent core temperature on physiologic parameters. PMID:24041214

Extraction of Solar Wind Nitrogen and Noble Gases From the Genesis Gold Foil Collector

NASA Astrophysics Data System (ADS)

Schlutter, D. J.; Pepin, R. O.

2005-12-01

The Genesis gold foil is a bulk solar wind collector, integrating fluences from all three of the wind regimes. Pyrolytic extraction of small foil samples at Minnesota yielded He fluences, corrected for backscatter, in good agreement with measurements by on-board spacecraft instruments, and He/Ne elemental ratios close to those implanted in collector foils deployed on the lunar surface during the Apollo missions. Isotopic distributions of He, Ne and Ar are under study. Pyrolysis to temperatures above the gold melting point generates nitrogen blanks large enough to obscure the solar-wind nitrogen component. An alternative technique for nitrogen and noble gas extraction, by room-temperature amalgamation of the gold foil surface, will be discussed. Ne and Ar releases in preliminary tests of this technique on small foil samples were close to 100% of the amounts expected from the high-temperature pyrolysis yields, indicating that amalgamation quantitatively liberates gases from several hundred angstroms deep in the gold, beyond the implantation depth of most of the solar wind. Present work is focused on two problems currently interfering with accurate nitrogen measurements at the required picogram to sub-picogram levels: a higher than expected blank likely due to tiny air bubbles rolled into the gold sheet during fabrication, and the presence of a refractory hydrocarbon film on Genesis collector surfaces (the "brown stain") that, if left in place on the foil, shields the underlying gold from mercury attack. We have found, however, that the film is efficiently removed within tens of seconds by oxygen plasma ashing. Potential nitrogen contaminants introduced during the crash of the sample return canister are inert in amalgamation, and so are not hazards to the measurements.

Effect of input perturbation on the performance and wake dynamics of aquatic propulsion in heaving flexible foils

NASA Astrophysics Data System (ADS)

Lehn, Andrea M.; Thornycroft, Patrick J. M.; Lauder, George V.; Leftwich, Megan C.

2017-02-01

In this paper we consider the effects of adding high-frequency, low-amplitude perturbations to a smooth sinusoidal base input signal for a heaving panel in a closed loop flow tank. Specifically, 0.1 cm amplitude sinusoidal perturbation waves with frequency fp ranging from 0.5 to 13.0 Hz are added to 1 cm heave sinusoids with base frequencies, fb, ranging from 0.5 to 3.0 Hz. Two thin foils with different flexural stiffness are heaved with the combined input signals in addition to both the high-heave and low-heave signals independently. In all cases, the foils are heaved in a recirculating water channel with an incoming velocity of Vx=10 cm/s and a Reynolds number based on the chord length of Re=17 300 . Results demonstrate that perturbations increase the net axial force, in the streamwise direction, in most cases tested (with the exception of some poor performing flexible foil cases). Most significantly, for a base frequency of 1 Hz, perturbations at 9 Hz result in a 780.7% increase in net streamwise force production. Generally, the higher the perturbation frequency, fp the more axial force generated. However, for the stiffer foil, a clear peak in net force exists at fp=9 Hz , regardless of the base frequency. For the stiffer foil, swimming efficiency at a 1 Hz flapping frequency is increased dramatically with the addition of a perturbation, with reduced efficiency increases at higher flapping frequencies. Likewise, for the flexible foil, swimming efficiency gains are greatest at the lower flapping frequencies. Perturbations alter the wake structure by increasing the vorticity magnitude and increasing the vortex shedding frequency; i.e., more, stronger vortices are produced in each flapping cycle.

Rotordynamics and Design Methods of an Oil-Free Turbocharger

NASA Technical Reports Server (NTRS)

Howard, Samuel A.

1999-01-01

The feasibility of supporting a turbocharger rotor on air foil bearings is investigated based upon predicted rotordynamic stability, load accommodations, and stress considerations. It is demonstrated that foil bearings offer a plausible replacement for oil-lubricated bearings in diesel truck turbochargers. Also, two different rotor configurations are analyzed and the design is chosen which best optimizes the desired performance characteristics. The method of designing machinery for foil bearing use and the assumptions made are discussed.

High-quality uniform dry transfer of graphene to polymers.

PubMed

Lock, Evgeniya H; Baraket, Mira; Laskoski, Matthew; Mulvaney, Shawn P; Lee, Woo K; Sheehan, Paul E; Hines, Daniel R; Robinson, Jeremy T; Tosado, Jacob; Fuhrer, Michael S; Hernández, Sandra C; Walton, Scott G

2012-01-11

In this paper we demonstrate high-quality, uniform dry transfer of graphene grown by chemical vapor deposition on copper foil to polystyrene. The dry transfer exploits an azide linker molecule to establish a covalent bond to graphene and to generate greater graphene-polymer adhesion compared to that of the graphene-metal foil. Thus, this transfer approach provides a novel alternative route for graphene transfer, which allows for the metal foils to be reused. © 2011 American Chemical Society

Large-area thin self-supporting carbon foils with MgO coatings

NASA Astrophysics Data System (ADS)

Stolarz, Anna; Maier-Komor, Peter

2002-03-01

Large area self-supporting carbon foils in the thickness of range of 8-22 μg/cm 2, coated with approximately 4 μg/cm 2 MgO have been prepared by e-gun evaporation. They were mounted on frames with apertures of 130 cm 2. Problems related to the parting agent preparation, floating procedure, and mounting onto frames are discussed. Special precautions necessary to avoid damage during foil drying, storage and transportation are suggested.

Compliant hydrodynamic fluid journal bearing

NASA Technical Reports Server (NTRS)

Warren, E. L. (Inventor)

1985-01-01

An air bearing structure is described that prevents destructive bending moments within the top foil. Welds are eliminated by mounting the top bearing foil in the bearing cartridge sleeve without using a space block. Tabs or pins at the end of the top bearing foil are restrained by slots or stops formed in the cartridge sleeve. These structural members are free to move in a direction normal to the shaft while being restrained from movement in the direction of shaft rotation.

Process for Design Optimization of Honeycomb Core Sandwich Panels for Blast Load Mitigation

DTIC Science & Technology

2012-12-01

experiments. Numerical simulation using a single ‘Y’ cross-sectional unit cell model predicted the crush behavior quite well compared to experiments with...of foil glued together by an adhesive. LS-DYNA is used to carry out the virtual simulation . The foil is modeled by quadrilateral Belytschko-Tsay...aluminum alloy with bilinear isotropic-hardening elastoplastic material model is used for the foil. Since the yield and ultimate strength of the AL5052

Proof of the Feasibility of Coherent and Incoherent Schemes for Pumping a Gamma-Ray Laser

DTIC Science & Technology

1989-07-01

compounds held in plastic vials or cylindrical planchettes . Foils and planchertes were exposed with their faces normal to the machine center- line. The...irradiation; foils and planchettes were counted with a solid NaI(TI) detector system and vials were again studied with the well detector. Samples...P to flat planchettes , and F to metallic foils. The self-absorption corrections represent the fraction of fluorescent photons which reach the

Fluid-film foil bearings control engine heat

NASA Astrophysics Data System (ADS)

O'Connor, Leo

1993-05-01

The state-of-the-art of fluid-film foil bearings and their current and prospective applications are briefly reviewed. In particular, attention is given to the general design of fluid-film foil bearings, the materials used, and bearing performance. The applications discussed include launch vehicle turbopumps, turbines used to cool aircraft cabins, and turbocompressors and turboexpanders used in the processing of cryogenic fluids. Future applications may include turbochargers, textile spindles, cryocoolers, motor blowers, heat pumps, and solar chillers.

Joining of materials using laser heating

DOEpatents

Cockeram, Brian V.; Hicks, Trevor G.; Schmid, Glenn C.

2003-07-01

A method for diffusion bonding ceramic layers such as boron carbide, zirconium carbide, or silicon carbide uses a defocused laser beam to heat and to join ceramics with the use of a thin metal foil insert. The metal foil preferably is rhenium, molybdenum or titanium. The rapid, intense heating of the ceramic/metal/ceramic sandwiches using the defocused laser beam results in diffusive conversion of the refractory metal foil into the ceramic and in turn creates a strong bond therein.

Light scattering apparatus and method for determining radiation exposure to plastic detectors

DOEpatents

Hermes, Robert E.

2002-01-01

An improved system and method of analyzing cumulative radiation exposure registered as pits on track etch foils of radiation dosimeters. The light scattering apparatus and method of the present invention increases the speed of analysis while it also provides the ability to analyze exposure levels beyond that which may be properly measured with conventional techniques. Dosimeters often contain small plastic sheets that register accumulated damage when exposed to a radiation source. When the plastic sheet from the dosimeter is chemically etched, a track etch foil is produced wherein pits or holes are created in the plastic. The number of these pits, or holes, per unit of area (pit density) correspond to the amount of cumulative radiation exposure which is being optically measured by the apparatus. To measure the cumulative radiation exposure of a track etch foil a high intensity collimated beam is passed through foil such that the pits and holes within the track etch foil cause a portion of the impinging light beam to become scattered upon exit. The scattered light is focused with a lens, while the primary collimated light beam (unscattered light) is blocked. The scattered light is focused by the lens onto an optical detector capable of registering the optical power of the scattered light which corresponds to the cumulative radiation to which the track etch foil has been exposed.

A heater made from graphite composite material for potential deicing application

NASA Technical Reports Server (NTRS)

Hung, C. C.; Stahl, M.; Stahl, M.; Stahl, M.

1986-01-01

A surface heater was developed using a graphite fiber-epoxy composite as the heating element. This heater can be thin, highly electrically and thermally conductive, and can conform to an irregular surface. Therefore it may be used in an aircraft's thermal deicing system to quickly and uniformly heat the aircraft surface. One-ply of unidirectional graphite fiber-epoxy composite was laminated between two plies of fiber glass-epoxy composite, with nickel foil contacting the end portions of the composite and partly exposed beyond the composites for electrical contact. The model heater used brominated P-100 fibers from Amoco. The fiber's electrical resistivity, thermal conductivity and density were 50 micro ohms per centimeter, 270 W/m-K and 2.30 gm/cubic cm, respectively. The electricity was found to penetrate through the composite in the transverse direction to make an acceptably low foil-composite contact resistance. When conducting current, the heater temperature increase reached 50 percent of the steady state value within 20 sec. There was no overheating at the ends of the heater provided there was no water corrosion. If the foil-composite bonding failed during storage, liquid water exposure was found to oxidize the foil. Such bonding failure may be avoided if perforated nickel foil is used, so that the composite plies can bond to each other through the perforated holes and therefore lock the foil in place.

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.

Mid-term variation of vertical distribution of acid volatile sulphide and simultaneously extracted metals in sediment cores from Lake Albufera (Valencia, Spain).

PubMed

Hernández-Crespo, Carmen; Martín, Miguel

2013-11-01

Lake Albufera is one of the most eutrophic bodies of water in Spain due to point and diffuse pollution over past decades, and its sediments are likely to be anoxic because of high organic matter flux. Hence, sulphides can play an important role in limiting the mobility of heavy metals. This study aimed to study the vertical variation of acid volatile sulphide (AVS) and simultaneously extracted metals (SEM) in sediment cores collected from Lake Albufera; other sediment characteristics, such as organic matter, biochemical oxygen, demand or total metals, were also studied. Three sites were selected, and four sampling campaigns were performed to study spatial and temporal variation as well as to obtain information regarding historical variation in the composition of sediments. AVS and SEM were analysed by the purge-and-trap method. The vertical distribution of AVS and SEM varied depending on the sampling site-concentrations of AVS and SEM were higher at sites close to mouths of inflowing channels. A decreasing trend of AVS has been found at these sites over time: In the two first samplings, AVS increased with depth reaching maximum concentrations of 40 and 21 μmol g(-1), but from then on AVS were lower and decreased with depth. SEM decreased with depth from 3 μmol g(-1) in surface layers to approximately 1 μmol g(-1) at deeper segments at these sites. However, the central site was more uniform with respect to depth as well as with time; it presented lower values of SEM and AVS (mean 0.9 and 2.0 μmol g(-1) respectively), and the maximum value of AVS (7 μmol g(-1)) was found at the top layer (0-3 cm). According to the (SEM-AVS)/fOC approach, every site, and throughout the cores, can be classified as containing nontoxic metals because the values were <130 μmol g(-1).

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.

Analytical study of graphite-epoxy tube response to thermal loads

NASA Technical Reports Server (NTRS)

Knott, Tamara W.; Hyer, M. W.

1988-01-01

The thermally-induced stresses and deformations in graphite-epoxy tubes with aluminum foil bonded to both inner and outer surfaces, and to the outer surface only are computed. Tubes fabricated from three material systems, T300/934, P75s/934, and P75s/BP907, and having a 1 inch inner radius and a lamination sequence of (+15/0 + or - 10/0)sub s are studied. Radial, axial, and circumferential stresses in the various layers of the tube, in the foil, and in the adhesive bonding the foil to the tubes are computed using an elasticity solution. The results indicate that the coatings have no detrimental effect on the stress state in the tube, particularly those stresses that lead to microcracking. The addition of the aluminum foil does, however, significantly influence the axial expansion of the T300/934 tube, the tube with the softer graphite fibers. The addition of foil can change the sign of the axial coefficient of thermal expansion. Twist tendencies of the tubes are only slightly affected by the addition of the coatings, but are of second order compared to the axial response.

Conductive copper sulfide thin films on polyimide foils

NASA Astrophysics Data System (ADS)

Cardoso, J.; Gomez Daza, O.; Ixtlilco, L.; Nair, M. T. S.; Nair, P. K.

2001-02-01

Kapton polyimide is known for its high thermal stability, >400 °C. Copper sulfide thin films of 75 and 100 nm thickness were coated on DuPont Kapton HN polyimide foils of 25 µm thickness by floating them on a chemical bath containing copper complexes and thiourea. The coated foils were annealed at 150-400 °C in nitrogen, converting the coating from CuS to Cu1.8S. The sheet resistance of the annealed coatings (100 nm) is 10-50 Ω/□ and electrical conductivity, 2-10×103 Ω-1 cm- 1, which remain nearly constant even after the foils are immersed in 0.1-1 M HCl for 30-120 min. The coated polyimide has a transmittance (25-35%) peak located in the wavelength region 550-600 nm, with transmittance dropping to near zero below 450 nm and below 10% in the near-infrared spectral region. These characteristics are relevant in solar radiation control applications. The coated foils might also be used as conductive substrates for electrolytic deposition of metals and semiconductors and for optoelectronic device structures.

Conducting-polymer-driven actively shaped propellers and screws

NASA Astrophysics Data System (ADS)

Madden, John D.; Schmid, Bryan; Lafontaine, Serge R.; Madden, Peter G. A.; Hover, Franz S.; McLetchie, Karl; Hunter, Ian W.

2003-07-01

Conducting polymer actuators are employed to create actively shaped hydrodynamic foils. The active foils are designed to allow control over camber, much like the ailerons of an airplane wing. Control of camber promises to enable variable thrust in propellers and screws, increased maneuverability, and improved stealth. The design and fabrication of the active foils are presented, the forces are measured and operation is demonstrated both in still air and water. The foils have a "wing" span of 240 mm, and an average chord length (width) of 70 mm. The trailing 30 mm of the foil is composed of a thin polypyrrole actuator that curls chordwise to achieve variable camber. The actuator consists of two 30 μm thick sheets of hexafluorophosphate doped polypyrrole separated from each other by a gel electrolyte. A polymer layer encapsulates the entire structure. Potentials are applied between the polymer layers to induce reversible bending by approximately 35 degrees, and generating forces of 0.15 N. These forces and displacements are expected to enable operation in water at flow rates of > 1 m/s and ~ 30 m/s in air.

Fragmentation of copper current collectors in Li-ion batteries during spherical indentation

NASA Astrophysics Data System (ADS)

Wang, Hsin; Watkins, Thomas R.; Simunovic, Srdjan; Bingham, Philip R.; Allu, Srikanth; Turner, John A.

2017-10-01

Large, areal, brittle fracture of copper current collector foils has been observed by 3D x-ray computed tomography (XCT) of a spherically indented Li-ion cell. This fracture is hidden and non-catastrophic to a degree because the graphite layers deform plastically, and hold the materials together so that the cracks in the foils cannot be seen under optical and electron microscopy. The cracking of copper foils could not be immediately confirmed when the cell is opened for post-mortem examination. However, 3D XCT on the indented cell reveals ;mud cracks; within the copper layer and an X-ray radiograph on a single foil of the Cu anode shows clearly that the copper foil has broken into multiple pieces. This failure mode of anodes in Li-ion cell has very important implications on the behavior of Li-ion cells under mechanical abuse conditions. The fragmentation of current collectors in the anode must be taken into consideration for the electrochemical responses which may lead to capacity loss and affect thermal runaway behavior of the cells.

Tribological composition optimization of chromium-carbide-based solid lubricant coatings for foil gas bearings at temperatures to 650 C

NASA Technical Reports Server (NTRS)

Dellacorte, Christopher

1988-01-01

The determination of the tribilogically optimum composition of chromium-carbide-based solid lubricant coatings using a foil gas bearing test apparatus is described. The coatings contain a wear resistant chromium carbide `base stock' with the lubricant additives silver and BaF2-CaF2 eutectic. The coating composition is optimized for air-lubricated foil gas bearings at temperatures ranging from 25 to 650 C. The various compositions were prepared by powder blending, then plasma sprayed onto Inconel 718 test journals and diamond ground to the desired coating thickness and surface finish. The journals were operated against preoxidized Ni-Cr alloy foils, and the test bearings were subjected to repeated start-stop cycles under a bearing unit of 14 kPa. Sliding contact between the coated journal and the smooth foil occurs during bearing start-up before lift-off or hydrodynamic lubrication by the air film and during bearing coast-down. The bearings were tested for 9000 start-stop cycles or until specimen reached a predetermined failure level.

Multilayer-based lab-on-a-chip systems for perfused cell-based assays

NASA Astrophysics Data System (ADS)

Klotzbach, Udo; Sonntag, Frank; Grünzner, Stefan; Busek, Mathias; Schmieder, Florian; Franke, Volker

2014-12-01

A novel integrated technology chain of laser-microstructured multilayer foils for fast, flexible, and low-cost manufacturing of lab-on-a-chip devices especially for complex cell and tissue culture applications, which provides pulsatile fluid flow within physiological ranges at low media-to-cells ratio, was developed and established. Initially the microfluidic system is constructively divided into individual layers, which are formed by separate foils or plates. Based on the functional boundary conditions and the necessary properties of each layer, their corresponding foils and plates are chosen. In the third step, the foils and plates are laser microstructured and functionalized from both sides. In the fourth and last manufacturing step, the multiple plates and foils are joined using different bonding techniques like adhesive bonding, welding, etc. This multilayer technology together with pneumatically driven micropumps and valves permits the manufacturing of fluidic structures and perfusion systems, which spread out above multiple planes. Based on the established lab-on-a-chip platform for perfused cell-based assays, a multilayer microfluidic system with two parallel connected cell culture chambers was successfully implemented.

A bioinspired aquatic robot propelled by an internal rotor

NASA Astrophysics Data System (ADS)

Tallapragada, Phanindra; Pollard, Beau

2015-11-01

Low dimensional models of fish-like swimming of a deformable Joukowski foil shedding singular distributions of vorticity have been well known for two decades. The deformation of the foil can be interpreted to be periodic changes in an abstract shape space and the creation of vorticity can be shown to act as a nonholonomic constraint. With this geometric insight, it can be demonstrated that a Joukowski foil (or in general any body) can possibly swim to the motion of an internal rotor, that acts as a shape variable. The motion of the rotor pumps in angular momentum and the simultaneous creation of vorticity allows this to be `converted' into linear momentum of the foil. We demonstrate the feasibility of this theoretical prediction with a robot shaped as a Joukowski foil propelled by the motion of an internal momentum wheel. We also demonstrate that the internal rotor acts both as a means of propulsion as well as a means of controlling the heading of the robot. Some maneuvers of the robot and features of its physical and `mathematical' resemblance to fish-like motion are demonstrated.

Advancements Toward Oil-Free Rotorcraft Propulsion

NASA Technical Reports Server (NTRS)

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

2010-01-01

NASA and the Army have been working for over a decade to advance the state-of-the-art (SOA) in Oil-Free Turbomachinery with an eye toward reduced emissions and maintenance, and increased performance and efficiency among other benefits. Oil-Free Turbomachinery is enabled by oil-free gas foil bearing technology and relatively new high-temperature tribological coatings. Rotorcraft propulsion is a likely candidate to apply oil-free bearing technology because the engine size class matches current SOA for foil bearings and because foil bearings offer the opportunity for higher speeds and temperatures and lower weight, all critical issues for rotorcraft engines. This paper describes an effort to demonstrate gas foil journal bearing use in the hot section of a full-scale helicopter engine core. A production engine hot-core location is selected as the candidate foil bearing application. Rotordynamic feasibility, bearing sizing, and load capability are assessed. The results of the program will help guide future analysis and design in this area by documenting the steps required and the process utilized for successful application of oil-free technology to a full-scale engine.

Reanalysis of tritium production in a sphere of /sup 6/LiD irradiated by 14-MeV neutrons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fawcett, L.R. Jr.

1985-08-01

Tritium production and activation of radiochemical detector foils in a sphere of /sup 6/LiD irradiated by a central source of 14-MeV neutrons has been reanalyzed. The /sup 6/LiD sphere consisted of 10 solid hemispherical nested shells with ampules of /sup 6/LiH, /sup 7/LiH, and activation foils located 2.2, 5, 7.7, 12.6, 20, and 30 cm from the center. The Los Alamos Monte Carlo Neutron Photon Transport Code (MCNP) was used to calculate neutron transport through the /sup 6/LiD, tritium production in the ampules, and foil activation. The MCNP input model was three-dimensional and employed ENDF/B-V cross sections for transport, tritiummore » production, and (where available) foil activation. The reanalyzed experimentally observed-to-calculated values of tritium production were 1.053 +- 2.1% in /sup 6/LiH and 0.999 +- 2.1% in /sup 7/LiH. The recalculated foil activation observed-to-calculated ratios were not generally improved over those reported in the original analysis.« less

Formation of a pinched electron beam and an intense x-ray source in radial foil rod-pinch diodes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sorokin, S. A.

2016-04-15

Low-impedance rod-pinch diode experiments were performed on the MIG generator at Institute of High Current Electronics using an aluminum foil placed between concentric electrodes of a rod-pinch diode. The J × B force accelerates the foil plasma in the axial and radial directions. After the foil plasma is pushed beyond the tip of the rod, a vacuum gap and a pinched electron beam form. The anode and cathode plasmas expansion and the following plasmas sweeping up by the J × B force can result in repetitive gap formations and closures, which are evident in the several successive intense x-ray pulses. A 0.7-mm-size point-like x-raymore » source was realized using a 1-mm-diameter tungsten rod, tapered to a point over the last 10 mm. The results of experiments show that the foil-shorted rod-pinch diode configuration has the potential to form low-impedance diodes, to shorten x-ray pulse duration and to realize submillimeter spot-size x-ray sources.« less

Experimental and Theoretical Study on Minimum Achievable Foil Thickness during Asymmetric Rolling

PubMed Central

Tang, Delin; Liu, Xianghua; Song, Meng; Yu, Hailiang

2014-01-01

Parts produced by microforming are becoming ever smaller. Similarly, the foils required in micro-machines are becoming ever thinner. The asymmetric rolling technique is capable of producing foils that are thinner than those produced by the conventional rolling technique. The difference between asymmetric rolling and conventional rolling is the ‘cross-shear’ zone. However, the influence of the cross-shear zone on the minimum achievable foil thickness during asymmetric rolling is still uncertain. In this paper, we report experiments designed to understand this critical influencing factor on the minimum achievable thickness in asymmetric rolling. Results showed that the minimum achievable thickness of rolled foils produced by asymmetric rolling with a rolling speed ratio of 1.3 can be reduced to about 30% of that possible by conventional rolling technique. Furthermore, the minimum achievable thickness during asymmetric rolling could be correlated to the cross-shear ratio, which, in turn, could be related to the rolling speed ratio. From the experimental results, a formula to calculate the minimum achievable thickness was established, considering the parameters cross-shear ratio, friction coefficient, work roll radius, etc. in asymmetric rolling. PMID:25203265

3D Structure of the Inverse Karman Vortex Street in the Wake of a Flapping Foil

NASA Astrophysics Data System (ADS)

Bozkurttas, Meliha; Mittal, Rajat; Dong, Haibo

2004-11-01

Flapping foils are being considered for lift generation and/or propulsion in Micro Aerial Vehicles (MAVs) and Autonomous Underwater Vehicles (AUVs). In the present study, a DNS/LES solver that is capable of simulating these flows in all their complexity will be used. The flow around a NACA 0012 foil undergoing pitch oscillation at a chord Reynolds number of 12600 has been investigated and the comparison of mean thrust coefficient results with the experiment has indicated significant under-prediction of the thrust although good match is observed with a 2D RANS calculation. This discrepancy could be related to the absence of 3D effects in both numerical simulations. Although this conclusion has also been reached in other studies, the details of the physical mechanism that lead to inaccurate prediction of surface pressure and ultimately to thrust force for pitching and heaving flapping foils have not been clarified yet. In this study, the streamwise (secondary) vortical structures in the inverse Karman Vortex Street generated in the wake of a thrust producing flapping foil will be studied.

A concept for Z-dependent microbunching measurements with coherent X-ray transition radiation in a sase FEL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lumpkin, A.H.; Fawley, W.M.; Rule, D.W.

We present an adaptation of the measurements performed in the visible-to-VUV regime of the z-dependent microbunching in a self-amplified spontaneous emission (SASE) free-electron laser (FEL). In these experiments a thin metal foil was used to block the more intense SASE radiation and to generate coherent optical transition radiation (COTR) as one source in a two-foil interferometer. However, for the proposed x-ray SASE FELs, the intense SASE emission is either too strongly transmitted at 1.5 Angstrom or the needed foil thickness for blocking scatters the electron beam too much. Since x-ray transition radiation (XTR) is emitted in an annulus with openingmore » angle 1/g = 36 mrad for 14.09-GeV electrons, we propose using a thin foil or foil stack to generate the XTR and coherent XTR (CXTR) and an annular crystal to wavelength sort the radiation. The combined selectivity in angle and wavelength will favor the CXTR over SASE by about eight orders of magnitude. Time-dependent GINGER simulations support the z-dependent gain evaluation plan.« less

Gas insulated transmission line having low inductance intercalated sheath

DOEpatents

Cookson, Alan H.

1978-01-01

A gas insulated transmission line including an outer sheath, an inner conductor disposed within the outer sheath, and an insulating gas between the inner conductor and the outer sheath. The outer sheath comprises an insulating tube having first and second ends, and having interior and exterior surfaces. A first electrically conducting foil is secured to the interior surface of the insulating tube, is spirally wound from one tube end to the second tube end, and has a plurality of overlapping turns. A second electrically conducting foil is secured to the exterior surface of the insulating tube, and is spirally wound in the opposite direction from the first electrically conducting foil. By winding the foils in opposite directions, the inductances within the intercalated sheath will cancel each other out.

Electrical properties of Al foil/n-4H-SiC Schottky junctions fabricated by surface-activated bonding

NASA Astrophysics Data System (ADS)

Morita, Sho; Liang, Jianbo; Matsubara, Moeko; Dhamrin, Marwan; Nishio, Yoshitaka; Shigekawa, Naoteru

2018-02-01

We fabricate 17-µm-thick Al foil/n-4H-SiC Schottky junctions by surface-activated bonding. Their current-voltage and capacitance-voltage characteristics are compared with those of Schottky junctions fabricated by evaporating Al layers on n-4H-SiC epilayers. We find that the ideality factor of Al foil/SiC junctions is larger than that of conventional junctions, which is due to the irradiation of the fast atom beam (FAB) of Ar. The ideality factor of Al foil/SiC junctions is improved by annealing at 400 °C. We also find that the Schottky barrier height is increased by FAB irradiation, which is likely to be due to the negative charges formed at SiC surfaces.

Spectrometry and filtering with high rejection of stray light

DOEpatents

Ferrell, Thomas L.; Thundat, Thomas G.

2004-12-14

A microoptoelectromechanical integrated spectrometer with a photonic element assembly having metal foil removably disposed on a first transparent substrate surface, the substrate having no foil on any other surface. A means is provided for directing source photons that are reflected from or transmitted through a sample, over a range of angles of incidence, into the transparent substrate and onto the metal foil such that source photons are incident at the Brewsters angle. A means is also provided for detecting an induced exponential field in the metal foil. A means is also provided for relating the induced exponential field to a known exponential field for the sample and determining the identity of the sample. The spectrometer performs ultraviolet-to-visible-to-infrared spectroscopy using photon tunneling and surface plasmon excitation.