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Sample records for density-stratified thin keplerian

  1. General Relativistic Magnetohydrodynamic Simulations of Jet Formation with a Thin Keplerian Disk

    NASA Technical Reports Server (NTRS)

    Mizuno, Yosuke; Nishikawa, Ken-Ichi; Koide, Shinji; Hardee, Philip; Gerald, J. Fishman

    2006-01-01

    We have performed several simulations of black hole systems (non-rotating, black hole spin parameter a = 0.0 and rapidly rotating, a = 0.95) with a geometrically thin Keplerian disk using the newly developed RAISHIN code. The simulation results show the formation of jets driven by the Lorentz force and the gas pressure gradient. The jets have mildly relativistic speed (greater than or equal to 0.4 c). The matter is continuously supplied from the accretion disk and the jet propagates outward until each applicable terminal simulation time (non-rotating: t/tau S = 275 and rotating: t/tau S = 200, tau s equivalent to r(sub s/c). It appears that a rotating black hole creates an additional, faster, and more collimated inner outflow (greater than or equal to 0.5 c) formed and accelerated by the twisted magnetic field resulting from frame-dragging in the black hole ergosphere. This new result indicates that jet kinematic structure depends on black hole rotation.

  2. THE HANLE EFFECT AS A DIAGNOSTIC OF MAGNETIC FIELDS IN STELLAR ENVELOPES. V. THIN LINES FROM KEPLERIAN DISKS

    SciTech Connect

    Ignace, R.

    2010-12-10

    This paper focuses on the polarized profiles of resonance scattering lines that form in magnetized disks. Optically thin lines from Keplerian planar disks are considered. Model line profiles are calculated for simple field topologies of axial fields (i.e., vertical to the disk plane) and toroidal fields (i.e., purely azimuthal). A scheme for discerning field strengths and geometries in disks is developed based on Stokes Q - U diagrams for the run of polarization across line profiles that are Doppler-broadened by the disk rotation. A discussion of the Hanle effect for magnetized disks in which the magnetorotational instability (MRI) is operating is also presented. Given that the MRI has a tendency to mix the vector field orientation, it may be difficult to detect the disk fields with the longitudinal Zeeman effect, since the amplitude of the circularly polarized signal scales with the net magnetic flux in the direction of the observer. The Hanle effect does not suffer from this impediment, and so a multi-line analysis could be used to constrain field strengths in disks dominated by the MRI.

  3. Longitudinal Oscillations in Density Stratified and Expanding Solar Waveguides

    NASA Astrophysics Data System (ADS)

    Luna-Cardozo, M.; Verth, G.; Erdélyi, R.

    2012-04-01

    Waves and oscillations can provide vital information about the internal structure of waveguides in which they propagate. Here, we analytically investigate the effects of density and magnetic stratification on linear longitudinal magnetohydrodynamic (MHD) waves. The focus of this paper is to study the eigenmodes of these oscillations. It is our specific aim to understand what happens to these MHD waves generated in flux tubes with non-constant (e.g., expanding or magnetic bottle) cross-sectional area and density variations. The governing equation of the longitudinal mode is derived and solved analytically and numerically. In particular, the limit of the thin flux tube approximation is examined. The general solution describing the slow longitudinal MHD waves in an expanding magnetic flux tube with constant density is found. Longitudinal MHD waves in density stratified loops with constant magnetic field are also analyzed. From analytical solutions, the frequency ratio of the first overtone and fundamental mode is investigated in stratified waveguides. For small expansion, a linear dependence between the frequency ratio and the expansion factor is found. From numerical calculations it was found that the frequency ratio strongly depends on the density profile chosen and, in general, the numerical results are in agreement with the analytical results. The relevance of these results for solar magneto-seismology is discussed.

  4. LONGITUDINAL OSCILLATIONS IN DENSITY STRATIFIED AND EXPANDING SOLAR WAVEGUIDES

    SciTech Connect

    Luna-Cardozo, M.; Verth, G.; Erdelyi, R. E-mail: robertus@sheffield.ac.uk

    2012-04-01

    Waves and oscillations can provide vital information about the internal structure of waveguides in which they propagate. Here, we analytically investigate the effects of density and magnetic stratification on linear longitudinal magnetohydrodynamic (MHD) waves. The focus of this paper is to study the eigenmodes of these oscillations. It is our specific aim to understand what happens to these MHD waves generated in flux tubes with non-constant (e.g., expanding or magnetic bottle) cross-sectional area and density variations. The governing equation of the longitudinal mode is derived and solved analytically and numerically. In particular, the limit of the thin flux tube approximation is examined. The general solution describing the slow longitudinal MHD waves in an expanding magnetic flux tube with constant density is found. Longitudinal MHD waves in density stratified loops with constant magnetic field are also analyzed. From analytical solutions, the frequency ratio of the first overtone and fundamental mode is investigated in stratified waveguides. For small expansion, a linear dependence between the frequency ratio and the expansion factor is found. From numerical calculations it was found that the frequency ratio strongly depends on the density profile chosen and, in general, the numerical results are in agreement with the analytical results. The relevance of these results for solar magneto-seismology is discussed.

  5. Avoidance-preference testing in density stratified solutions

    SciTech Connect

    Smith, E.H.; Logan, D.T.; Hansen, S.

    1994-12-31

    Toxicity testing is sometimes required where density stratifies test and reference solutions. Examples include freshwater effluents that float in estuarine and marine waters and desalinating plant effluents that sink. Standard avoidance-preference testing methods and apparatus are designed to test horizontal rather than vertical gradients and so are inappropriate for density stratified solutions. To overcome associated deficiencies, the authors modified testing chambers to take advantage of density stratification. Exposure levels for tests were selected based on NOELs from standard toxicity testing. Behavior of 10 striped bass was simultaneously observed using electronic surveillance. Measure of behavior include position in two axes and swimming speed. Avoidance-preference between several types of high density byproducts of salt water evaporation and lower density receiving water were tested. Results indicate that the modified test protocols allowed the authors to determine behavior responses to test materials.

  6. Quantum image pseudocolor coding based on the density-stratified method

    NASA Astrophysics Data System (ADS)

    Jiang, Nan; Wu, Wenya; Wang, Luo; Zhao, Na

    2015-05-01

    Pseudocolor processing is a branch of image enhancement. It dyes grayscale images to color images to make the images more beautiful or to highlight some parts on the images. This paper proposes a quantum image pseudocolor coding scheme based on the density-stratified method which defines a colormap and changes the density value from gray to color parallel according to the colormap. Firstly, two data structures: quantum image GQIR and quantum colormap QCR are reviewed or proposed. Then, the quantum density-stratified algorithm is presented. Based on them, the quantum realization in the form of circuits is given. The main advantages of the quantum version for pseudocolor processing over the classical approach are that it needs less memory and can speed up the computation. Two kinds of examples help us to describe the scheme further. Finally, the future work are analyzed.

  7. Universal Keplerian state transition matrix

    NASA Technical Reports Server (NTRS)

    Shepperd, S. W.

    1985-01-01

    A completely general method for computing the Keplerian state transition matrix in terms of Goodyear's universal variables is presented. This includes a new scheme for solving Kepler's problem which is a necessary first step to computing the transition matrix. The Kepler problem is solved in terms of a new independent variable requiring the evaluation of only one transcendental function. Furthermore, this transcendental function may be conveniently evaluated by means of a Gaussian continued fraction.

  8. Magnetorotational decay instability in Keplerian disks.

    PubMed

    Shtemler, Yuri; Liverts, Edward; Mond, Michael

    2013-12-01

    The saturation of the magnetorotational instability (MRI) in thin Keplerian disks through three-wave resonant interactions is introduced and discussed. That mechanism is a natural generalization of the fundamental decay instability discovered five decades ago for infinite, homogeneous, and immovable plasmas. The decay instability relies on the energy transfer from the MRI to stable slow Alfvén-Coriolis as well as magnetosonic waves. A second-order forced Duffing amplitude equation for the initially unstable MRI as well as two first-order equations for the other two waves are derived. The solutions of those equations exhibit bounded bursty nonlinear oscillations for the MRI as well as unbounded growth for the linearly stable slow Alfvén-Coriolis and magnetosonic perturbations, thus giving rise to the magnetorotational decay instability. PMID:24476249

  9. On the Global Warping of a Thin Self-gravitating Near-Keplerian Gaseous Disk with Application to the Disk in NGC 4258

    NASA Astrophysics Data System (ADS)

    Papaloizou, John C. B.; Terquem, Caroline; Lin, Doug N. C.

    1998-04-01

    We derive the tilt equation governing the inclination of a thin self-gravitating gaseous disk subject to low-frequency global m = 1 bending perturbations. The disk orbits under the influence of a dominant central mass. However, self-gravity can be important enough that the disk approaches marginal stability to local axisymmetric perturbations (Q ~ 1). The vertical restoring forces due to self-gravity and pressure are evaluated correct to the first order in the aspect ratio H/r. Thus the effects of bending waves are included correct to lowest order in the wave-crossing rate (H/r)Ω, Ω being a characteristic disk rotation frequency. Both free and forced disturbances are considered. The disk response and precession frequency induced by the presence of a binary companion in an orbit with general inclination to the unperturbed disk plane are derived. When the degree of warping and the inclination are small, it is shown that identical results are obtained if, alternatively, perturbation of the disk out of an equilibrium plane coinciding with that of the companion is considered, the time-averaged potential due to the latter being incorporated into the equilibrium potential. The condition for the disk to precess approximately like a rigid body with a small degree of warping is found to be that the density-wave crossing time is significantly shorter than the precession period. We consider the effects of the presence of a viscosity that can be characterized with the standard α parameterization and find that, to the order we work, the precession frequency is unaffected, with any change to the inclination of the slightly warped disk occurring at a slower rate. For α << H/r, effects due to both pressure and self-gravity are important in the response, while for α >> H/r, the response becomes dominated by self-gravity with pressure effects becoming negligible. As an application of these results, we explore the possibility that the recently observed warped disk in the active

  10. COMPARISON OF NUMERICAL AND LABORATORY EXPERIMENTS ON DENSITY-STRATIFIED FLOWS AROUND A THREE-DIMENSIONAL HILL

    EPA Science Inventory

    Direct comparisons between the results of a numerical model and laboratory experiments are presented for density-stratified flows around an isolated three-dimensional hill. The numerical model integrates the Navier-Stokes equations for incompressible stratified flow using a finit...

  11. Circumnuclear Keplerian Disks in Galaxies

    NASA Astrophysics Data System (ADS)

    Bertola, Francesco; Cappellari, Michele; Funes, S. J., José G.; Corsini, Enrico M.; Pizzella, Alessandro; Beltrán, Juan C. Vega

    1998-12-01

    In this Letter, we demonstrate the possibility of inferring the presence of Keplerian gaseous disks using properly equipped optical ground-based telescopes. We have modeled the peculiar bidimensional shape of the emission lines in a sample of five early-type disk galaxies as due to the motion of a gaseous disk rotating in the combined potential of a central pointlike mass and of an extended stellar disk. The value of the central mass concentration estimated for four galaxies of the sample (NGC 2179, NGC 4343, NGC 4435, and NGC 4459) is ~109 Msolar. This value, according to the assumptions made in our model, is overestimated. However, we have calculated that the effect is well within the errors. For the remaining galaxy, NGC 5064, an upper limit of 5×107 Msolar is estimated. Based on observations carried out at ESO, La Silla, (Chile) (ESO N. 58, A-0564) and at the Mount Graham International Observatory (AZ) with the VATT: the Alice P. Lennon Telescope and the Thomas J. Bannan Astrophysics Facility.

  12. Hydrographic patterns in microbial communities in the density stratified Alaska Beaufort Shelf

    NASA Astrophysics Data System (ADS)

    Hamdan, L. J.; Gillevet, P. M.; Sikaroodi, M.; Greinert, J.; Treude, T.; Coffin, R. B.

    2011-12-01

    Although similar microbial communities have been observed globally in methane charged sediments, the mechanism of their dispersal is unknown. The ocean may be a physical barrier for dispersal of anaerobic microorganisms typically found in methane seeps. However, it is possible that bottom layers act as distribution conduits for dormant cells to locations where geochemical conditions would allow them to flourish. The Alaska Beaufort Shelf (ABS) was used to stage a preliminary study of dispersal patterns of microbial communities from methane influenced waters and sediments. During September 2009 three density stratified water masses were present on the ABS, including a low salinity Arctic surface layer, an intermediate Pacific layer, and a deep, cold and saline Atlantic layer. Microbial community composition was studied in each water mass and in underlying sediments to determine the influence of water mass on sediment community structure. Sediment cores were obtained using a piston corer. Water samples were retrieved using a CTD rosette, and hydrodynamic data (e.g., salinity, temperature, density, dissolved oxygen) were acquired simultaneously. Methane concentrations were measured using a GC-FID. Community composition was surveyed using Multitag Pyrosequencing (MTPS) and Length Heterogeneity-PCR (LH-PCR) by amplification of hypervariable regions of the archaeal and bacterial SSUrRNA. MTPS data were processed using the QIIME pipeline, and taxonomy was assigned using the RDP classifier. The Unifrac metric and multidimensional scaling analysis was used to determine similarity patterns. Distinct bacterial communities were evident in the three water masses. Sequences related to the SAR11 clade were highly abundant in the Arctic layer. Gammaproteobacteria related to the Thiotrichales were abundant in Pacific and Atlantic layers. Archaeal water column communities were relatively homogeneous, and unidentified Euryarchaeota dominated all three water masses. Microbial

  13. Appearance of Keplerian discs orbiting Kerr superspinars

    NASA Astrophysics Data System (ADS)

    Stuchlík, Zdeněk; Schee, Jan

    2010-11-01

    We study optical phenomena related to the appearance of Keplerian accretion discs orbiting Kerr superspinars predicted by string theory. The superspinar exterior is described by standard Kerr naked singularity geometry breaking the black hole limit on the internal angular momentum (spin). We construct local photon escape cones for a variety of orbiting sources that enable us to determine the superspinars silhouette in the case of distant observers. We show that the superspinar silhouette depends strongly on the assumed edge where the external Kerr spacetime is joined to the internal spacetime governed by string theory and significantly differs from the black hole silhouette. The appearance of the accretion disc is strongly dependent on the value of the superspinar spin in both their shape and frequency shift profile. Apparent extension of the disc grows significantly with the growing spin, while the frequency shift grows with the descending spin. This behaviour differs substantially from the appearance of discs orbiting black holes enabling thus, at least in principle, to distinguish clearly the Kerr superspinars and black holes. In vicinity of a Kerr superspinar the non-escaped photons have to be separated to those captured by the superspinar and those being trapped in its strong gravitational field leading to self-illumination of the disc that could even influence its structure and cause self-reflection effect of radiation of the disc. The amount of trapped photons grows with descending superspinar spin. We thus can expect significant self-illumination effects in the field of Kerr superspinars with near-extreme spin a ~ 1.

  14. Transition from the infalling envelope to the Keplerian disk around L1551 IRS 5

    SciTech Connect

    Chou, Ti-Lin; Takakuwa, Shigehisa; Yen, Hsi-Wei; Ohashi, Nagayoshi; Ho, Paul T. P.

    2014-11-20

    We present combined Submillimeter Array (SMA) +Atacama Submillimeter Telescope Experiment (ASTE) images of the Class I protobinary L1551 IRS 5 in the CS (J = 7-6) line, the submillimeter images of L1551 IRS 5 with the most complete spatial sampling ever achieved (0.''9-36''). The SMA image of L1551 IRS 5 in the 343 GHz dust-continuum emission is also presented, which shows an elongated feature along the northwest to southeast direction (∼160 AU × 80 AU), perpendicular to the associated radio jets. The combined SMA+ASTE images show that the high-velocity (≳1.5 km s{sup –1}) CS emission traces the structure of the dust component and shows a velocity gradient along the major axis, which is reproduced by a geometrically thin Keplerian-disk model with a central stellar mass of ∼0.5 M {sub ☉}. The low-velocity (≲1.3 km s{sup –1}) CS emission shows an extended (∼1000 AU) feature that exhibits slight south (blueshifted) to north (redshifted) emission offsets, which is modeled with a rotating and infalling envelope with a conserved angular momentum. The rotational motion of the envelope connects smoothly to the inner Keplerian rotation at a radius of ∼64 AU. The infalling velocity of the envelope is ∼three times lower than the free-fall velocity toward the central stellar mass of 0.5 M {sub ☉}. These results demonstrate transition from the infalling envelope to the Keplerian disk, consistent with the latest theoretical studies of disk formation. We suggest that sizable (r ∼ 50-200 AU) Keplerian disks are already formed when the protostars are still deeply embedded in the envelopes.

  15. Hydrodynamic turbulence in quasi-Keplerian rotating flows?

    NASA Astrophysics Data System (ADS)

    Shi, Liang; Avila, Marc; Hof, Bjoern; Liang Shi Team; Marc Avila Team; Bjoern Hof Team

    2013-11-01

    The origin of turbulence in astrophysical accretion discs has been under scrutiny for decades and remains still unclear. The velocity profiles of discs (Keplerien profiles) are centrifugally stable and therefore a different instability mechanism is required for turbulence to arise. While in hot discs turbulence can be triggered through magnetorotational instability, cooler discs lack sufficient ionization and it is unclear how turbulence sets in. In analogy to other linearly stable flows like pipe and Couette flow, subcritical transition to turbulence may be the mechanism. Recently, experimental studies of Taylor-Couette flow in quasi-Keplerian regime have given conflicting results and numerical simulations of above experimental flows showed that the top and bottom end-wall leads to strong deviations from the Keplerian velocity profile and drives turbulence. In order to clarify this, we perform direct numerical simulations of incompressible Taylor-Couette flow without end walls in the quasi Keplerian regime for Re up to 200000. Strong transient growth is observed and gives rise to strongly disorted motion, suggesting that for large enough Re this mechanism may lead to turbulence even for Keplerian flows. This work is supported by Deutsche Forschungsgemeinschaft (DFG) under project SFB 963 and Max Planck Society.

  16. Forbidden tangential orbit transfers between intersecting Keplerian orbits

    NASA Technical Reports Server (NTRS)

    Burns, Rowland E.

    1990-01-01

    The classical problem of tangential impulse transfer between coplanar Keplerian orbits is addressed. A completely analytic solution which does not rely on sequential calculation is obtained and this solution is used to demonstrate that certain initially chosen angles can produce singularities in the parameters of the transfer orbit. A necessary and sufficient condition for such singularities is that the initial and final orbits intersect.

  17. On the dynamical and geometrical symmetries of Keplerian motion

    NASA Astrophysics Data System (ADS)

    Wulfman, Carl E.

    2009-05-01

    The dynamical symmetries of classical, relativistic and quantum-mechanical Kepler systems are considered to arise from geometric symmetries in PQET phase space. To establish their interconnection, the symmetries are related with the aid of a Lie-algebraic extension of Dirac's correspondence principle, a canonical transformation containing a Cunningham-Bateman inversion, and a classical limit involving a preliminary canonical transformation in ET space. The Lie-algebraic extension establishes the conditions under which the uncertainty principle allows the local dynamical symmetry of a quantum-mechanical system to be the same as the geometrical phase-space symmetry of its classical counterpart. The canonical transformation converts Poincaré-invariant free-particle systems into ISO(3,1) invariant relativistic systems whose classical limit produces Keplerian systems. Locally Cartesian relativistic PQET coordinates are converted into a set of eight conjugate position and momentum coordinates whose classical limit contains Fock projective momentum coordinates and the components of Runge-Lenz vectors. The coordinate systems developed via the transformations are those in which the evolution and degeneracy groups of the classical system are generated by Poisson-bracket operators that produce ordinary rotation, translation and hyperbolic motions in phase space. The way in which these define classical Keplerian symmetries and symmetry coordinates is detailed. It is shown that for each value of the energy of a Keplerian system, the Poisson-bracket operators determine two invariant functions of positions and momenta, which together with its regularized Hamiltonian, define the manifold in six-dimensional phase space upon which motions evolve.

  18. On the magnetic viscosity in Keplerian accretion disks

    NASA Technical Reports Server (NTRS)

    Coroniti, F. V.

    1981-01-01

    The paper develops a model for the anomalous viscosity in accretion disks based on the hypothesis that the hydrodynamic turbulence within the disk takes the form of spatially localized magnetic flux cells. The local shear flow due to Keplerian differential rotation distorts the flux cell topology, converting shear flow energy into magnetic energy. In the radial diffusion approximation, the kinematic viscosity is estimated from the radial displacement and is shown to maximize at flux cell scale lengths for which the shear flow stopping and reconnection times are equal.

  19. Lunar gravity - A long-term Keplerian rate method

    NASA Technical Reports Server (NTRS)

    Ferrari, A. J.; Ananda, M. P.

    1977-01-01

    Nearside tracking data from Apollo subsatellites and Lunar Orbiter 5 are used to construct a model of the farside lunar gravity field. An indirect method of calculating the average effect of all the gravity anomalies which affect spacecraft orbits is reduced to a linear estimation problem by eliminating the integration of spacecraft dynamics. Doppler frequency shifts between the lunar satellite and earth-based tracking station are used to measure the line of sight velocity component between the orbiter and the tracker; gravity determination is then performed in a weighted least squares estimator which employs the orbital rates as data and formulates the normal equations using the associated Keplerian state. Simulations performed demonstrate that farside gravity features can be economically determined by use of gravity estimates obtained from long-period models of nearside orbiting tracks.

  20. Angular Momentum Transport in Quasi-Keplerian Accretion Disks

    NASA Astrophysics Data System (ADS)

    Subramanian, Prasad; Pujari, B. S.; Becker, Peter A.

    2004-03-01

    We reexamine arguments advanced by Hayashi & Matsuda (2001), who claim that several simple, physically motivated derivations based on mean free path theory for calculating the viscous torque in a quasi-Keplerian accretion disk yield results that are inconsistent with the generally accepted model. If correct, the ideas proposed by Hayashi & Matsudawould radically alter our understanding of the nature of the angular momentum transport in the disk, which is a central feature of accretion disk theory. However, in this paper we point out several fallacies in their arguments and show that there indeed exists a simple derivation based on mean free path theory that yields an expression for the viscous torque that is proportional to the radial derivative of the angular velocity in the accretion disk, as expected. The derivation is based on the analysis of the epicyclic motion of gas parcels in adjacent eddies in the disk.

  1. Invited Talk: Instabilities in near-keplerian systems

    NASA Astrophysics Data System (ADS)

    Madigan, Ann-Marie

    2015-05-01

    Closed orbits drive secular gravitational instabilities, and Kepler potentials are one of only two potentials in which bound orbits are closed. Though the Kepler potential is common in astrophysics -- relevant for stars orbiting massive black holes in the centers of galaxies, for planets orbiting stars, and for moons orbiting planets — few instabilities have been explored beyond the linear regime in this potential. I will present two new instabilities which grow exponentially from small initial perturbations and act to reorient eccentric orbits in near-Keplerian disks. The first results from forces in the plane of the disk and acts to spread orbits in eccentricity. The second instability results from forces out of the disk plane and drives orbits to high inclination. I will explain the dynamical mechanism behind each and make observational predictions for both planetary systems and galactic nuclei.

  2. Methane and Dissolved Organic Carbon Sustain an Ecosystem within a Density Stratified Coastal Aquifer of the Yucatan Peninsula, Mexico. Evidence for a Subterranean Microbial Loop?

    NASA Astrophysics Data System (ADS)

    Brankovits, David; Pohlman, John W.; Niemann, Helge; Leigh, Mary Beth; Casso, Michael; Alvarez Noguera, Fernando; Lehmann, Moritz F.; Iliffe, Thomas M.

    2016-04-01

    In coastal karst terrains, anchialine caves that meander in density stratified aquifers provide an exceptional opportunity for scientists to study in situ biogeochemical processes within the groundwater. The Caribbean coast of Mexico's Yucatan Peninsula contains over 1000 km of mapped cave passages, the densest known accumulation of anchialine caves in the world. A decades-old study based on the simple observation of 13C-depleted biomass in the cave-adapted fauna suggested biogeochemical processes related to methane-linked carbon cycling and/or other chemoautotrophic pathways as a source of energy and carbon. In this study, we utilized cave diving and a novel sampling device (the Octopipi) to obtain cm-scale water column profiles of methane, DOC and DIC concentrations and stable carbon isotope ratios to identify the energy sources and microbial processes that sustain life in these subterranean estuaries. High concentrations (up to 9522 nM) low-δ13C (as low as -67.5 permil) methane near the ceiling of the cave (in the fresh water section of the stratified water column) and evidence for methane oxidation in the brackish water portion of the water column suggest methane availability and consumption. Profiles obtained by the Octopipi demonstrate that virtually all of the methane (˜99%) is oxidized at the interface of anoxic freshwater and hypoxic brackish water masses. The high-methane water mass near the ceiling also contained elevated concentrations of DOC (851 μM) that displayed comparatively high δ13C (-27.8 to -28.2 permil), suggesting terrestrial organic matter input from the overlying soils. Low-methane brackish and saline water was characterized by lower DOC concentration (15 to 97 μM), yet with similar δ13C (-25.9 to -27.2 permil), suggesting significant terrestrial organic matter consumption or removal with increasing depth, from fresh to saline water, within the water column. The presence of 13C-depleted fatty acids (e.g., C16:1ω7c with δ13C

  3. Optimal BLS: Optimizing transit-signal detection for Keplerian dynamics

    NASA Astrophysics Data System (ADS)

    Ofir, Aviv

    2015-08-01

    Transit surveys, both ground- and space-based, have already accumulated a large number of light curves that span several years. We optimize the search for transit signals for both detection and computational efficiencies by assuming that the searched systems can be described by Keplerian, and propagating the effects of different system parameters to the detection parameters. Importnantly, we mainly consider the information content of the transit signal and not any specific algorithm - and use BLS (Kovács, Zucker, & Mazeh 2002) just as a specific example.We show that the frequency information content of the light curve is primarily determined by the duty cycle of the transit signal, and thus the optimal frequency sampling is found to be cubic and not linear. Further optimization is achieved by considering duty-cycle dependent binning of the phased light curve. By using the (standard) BLS, one is either fairly insensitive to long-period planets or less sensitive to short-period planets and computationally slower by a significant factor of ~330 (for a 3 yr long dataset). We also show how the physical system parameters, such as the host star's size and mass, directly affect transit detection. This understanding can then be used to optimize the search for every star individually.By considering Keplerian dynamics explicitly rather than implicitly one can optimally search the transit signal parameter space. The presented Optimal BLS enhances the detectability of both very short and very long period planets, while allowing such searches to be done with much reduced resources and time. The Matlab/Octave source code for Optimal BLS is made available.

  4. Planetary Defense From Space: Part 1-Keplerian Theory

    NASA Astrophysics Data System (ADS)

    Maccone, Claudio

    A system of two space bases housing missiles is proposed to achieve the Planetary Defense of the Earth against dangerous asteroids and comets. We show that the layout of the Earth-Moon system with the five relevant Lagrangian (or libration) points in space leads naturally to only one, unmistakable location of these two space bases within the sphere of influence of the Earth. These locations are at the two Lagrangian points L1 (in between the Earth and the Moon) and L3 (in the direction opposite to the Moon from the Earth). We show that placing bases of missiles at L1 and L3 would cause those missiles to deflect the trajectory of asteroids by hitting them orthogonally to their impact trajectory toward the Earth, so as to maximize their deflection. We show that the confocal conics are the best class of trajectories fulfilling this orthogonal deflection requirement. An additional remark is that the theory developed in this paper is just a beginning of a larger set of future research work. In fact, while in this paper we only develop the Keplerian analytical theory of the Optimal Planetary Defense achievable from the Earth-Moon Lagrangian points L1 and L3, much more sophisticated analytical refinements would be needed to: Take into account many perturbation forces of all kinds acting on both the asteroids and missiles shot from L1 and L3; add more (non-optimal) trajectories of missiles shot from either the Lagrangian points L4 and L5 of the Earth-Moon system or from the surface of the Moon itself; encompass the full range of missiles currently available to the US (and possibly other countries) so as to really see "which asteroids could be diverted by which missiles", even in the very simplified scheme outlined here. Outlined for the first time in February 2002, our Confocal Planetary Defense concept is a Keplerian Theory that proved simple enough to catch the attention of scholars, representatives of the US Military and popular writers. These developments could

  5. Keplerian periodogram for Doppler exoplanet detection: optimized computation and analytic significance thresholds

    NASA Astrophysics Data System (ADS)

    Baluev, Roman V.

    2015-01-01

    We consider the so-called Keplerian periodogram, in which the putative detectable signal is modelled by a highly non-linear Keplerian radial velocity function, appearing in Doppler exoplanetary surveys. We demonstrate that for planets on high-eccentricity orbits the Keplerian periodogram is far more efficient than the classic Lomb-Scargle periodogram and even the multiharmonic periodograms, in which the periodic signal is approximated by a truncated Fourier series. We provide a new numerical algorithm for computation of the Keplerian periodogram. This algorithm adaptively increases the parametric resolution where necessary, in order to uniformly cover all local optima of the Keplerian fit. Thanks to this improvement, the algorithm provides more smooth and reliable results with minimized computing demands. We also derive a fast analytic approximation to the false alarm probability levels of the Keplerian periodogram. This approximation has the form (Pz3/2 + Qz)Wexp ( - z), where z is the observed periodogram maximum, W is proportional to the settled frequency range, and the coefficients P and Q depend on the maximum eccentricity to scan.

  6. Floquet analysis of two-dimensional perturbed Keplerian flows in cataclysmic variables

    NASA Astrophysics Data System (ADS)

    Tamburini, F.; Bianchini, A.; Franceschini, A.

    2010-09-01

    Aims: We apply Floquet analysis to study the dynamical stability of two-dimensional axisymmetric Keplerian flows distorted by an m = 2 epicyclic periodic forcing term, representing a tidal perturbation in a thin accretion disk (AD) of a cataclysmic variable (CV). This tidal mode is responsible for the disk truncation mechanism. Methods: Floquet analysis reveals, with a positive Floquet exponent, exponentially growing modes of the local instabilities that can cause the disruption of the AD. The equations of the inviscid fluid used to model the AD describe an oversimplified two-dimensional tidally-distorted accretion disk. Viscosity and the other properties expected in a CV AD are taken from the Shakura-Sunyaev α-disk solution and introduced in the model through the thermodynamical quantities present in the equations. In particular, we address this investigation in search of parametric resonances of the radial Fourier components of the velocity field in the multi-dimensional parameter space of the solutions describing a fluid stream in a CV AD: the mass of the primary M1, the orbital period p of the system, the orbital fiducial radius r of the fluid stream and the normalized Fourier mode of the radial motion, k. Results: We find that, in region of the r3:2 orbital resonance radius, where superhumps (SH) form, the m = 2 tidal epicyclic modes alone would not introduce any perturbation in this region of the AD, and therefore the Floquet exponent of the m = 2 tidal force is found to be either negative or zero. However, only by introducing the 3:1 tidal perturbation, will the dynamics of the fluid streams at the SH radius become unstable indicating the onset of SH. Finally, Floquet analysis of the Fourier decomposition of the derivative along the radial x-direction shows the important role of the low Fourier modes of the radial velocity perturbations in the disk truncation mechanism.

  7. Stability of quasi-Keplerian Shear Flow in a Laboratory Experiment

    SciTech Connect

    Schartman, Ethan; Ji, Hantao; Burin, Michael J.; Goodman, Jeremy

    2012-06-19

    Subcritical transition to turbulence has been proposed as a source of turbulent viscosity required for the associated angular momentum transport for fast accretion in Keplerian disks. Previously cited laboratory experiments in supporting this hypothesis were performed either in a di erent type of flow than Keplerian or without quantitative measurements of angular momentum transport and mean flow profile, and all of them appear to su er from Ekman e ects, secondary flows induced by nonoptimal axial boundary conditions. Such Ekman e ects are expected to be absent from astronomical disks, which probably have stress-free vertical boundaries unless strongly magnetized. Aims. To quantify angular momentum transport due to subcritical hydrodynamic turbulence, if exists, in a quasi-Keplerian flow with minimized Ekman e ects. Methods.We perform a local measurement of the azimuthal-radial component of the Reynolds stress tensor in a novel laboratory apparatus where Ekman e ects are minimized by flexible control of axial boundary conditions. Results.We find significant Ekman e ects on angular momentum transport due to nonoptimal axial boundary conditions in quasi-Keplerian flows. With the optimal control of Ekman e ects, no statistically meaningful angular momentum transport is detected in such flows at Reynolds number up to two millions. Conclusions. Either a subcritical transition does not occur, or, if a subcritical transition does occur, the associated radial transport of angular momentum in optimized quasi-Keplerian laboratory flows is too small to directly support the hypothesis that subcritical hydrodynamic turbulence is responsible for accretion in astrophysical disks. Possible limitations in applying laboratory results to astrophysical disks due to experimental geometry are discussed.

  8. Evidence for Infalling Gas of Low Angular Momentum toward the L1551 NE Keplerian Circumbinary Disk

    NASA Astrophysics Data System (ADS)

    Takakuwa, Shigehisa; Saito, Masao; Lim, Jeremy; Saigo, Kazuya

    2013-10-01

    We report follow-up C18O(3-2) line observations of the Class I binary protostellar system L1551 NE with the Submillimeter Array in its compact and subcompact configurations. Our previous observations at a higher angular resolution in the extended configuration revealed a circumbinary disk exhibiting Keplerian motion. The combined data, with more extensive spatial coverage (~140-2000 AU), verify the presence of a Keplerian circumbinary disk and reveal for the first time a distinct low-velocity (lsim ± 0.5 km s-1 from the systemic velocity) component that displays a velocity gradient along the minor axis of the circumbinary disk. Our simple model that reproduces the main features seen in the position-velocity diagrams comprises a circumbinary disk exhibiting Keplerian motion out to a radius of ~300 AU, beyond which the gas exhibits pure infall at a constant velocity of ~0.6 km s-1. This velocity is significantly smaller than the expected free-fall velocity of ~2.2 km s-1 onto the L1551 NE protostellar mass of ~0.8 M ⊙ at ~300 AU, suggesting that the infalling gas is decelerated as it moves into regions of high gas pressure in the circumbinary disk. The discontinuity in angular momenta between the outer infalling gas and the inner Keplerian circumbinary disk implies an abrupt transition in the effectiveness at which magnetic braking is able to transfer angular momentum outward, a result perhaps of the different plasma β values and the ionization fractions between the outer and inner regions of the circumbinary disk.

  9. A Gauge-generalized Solution for Non-Keplerian Motion in the Frenet-Serret Frame

    NASA Astrophysics Data System (ADS)

    Garber, Darren D.

    2009-05-01

    The customary modeling of perturbed planetary and spacecraft motion as a continuous sequence of unperturbed two-body orbits (instantaneous ellipses) is conveniently assigned a physical interpretation through the Keplerian and Delaunay elements and complemented mathematically by the Lagrange-type equations which describe the evolution of these variables. If however the actual motion is very non-Keplerian (i.e. the perturbed orbit varies greatly from a two-body orbit), then its modeling by a sequence of conics is not necessarily optimal in terms of its mathematical description and its resulting physical interpretation. Since, in principle a curve of any type can be represented as a sequence of points from a family of curves of any other type (Efroimsky 2005), alternate non-conic curves can be utilized to better describe the perturbed non-Keplerian motion of the body both mathematically and with a physically relevant interpretation. Non-Keplerian motion exists in both celestial mechanics and astrodynamics as evident by the complex interactions within star clusters and also as the result of a spacecraft accelerating via ion propulsion, solar sails and electro-dynamic tethers. For these cases, the sequence of simple orbits to describe the motion is not based on conics, but instead a family of spirals. The selection of spirals as the underlying simple motion is supported by the fact that it is unnecessary to describe the motion in terms of instantaneous orbits tangent to the actual trajectory (Efroimsky 2002, Newman & Efroimsky 2003) and at times there is an advantage to deviate from osculation, in order to greatly simplify the resulting mathematics via gauge freedom (Efroimsky & Goldreich 2003, Slabinski 2003, Gurfil 2004). From these two principles, (1) spirals as instantaneous orbits, and (2) controlled deviation from osculation, new planetary equations are derived for new non-osculating elements in the Frenet-Serret frame with the gauge function as a measure of non-osculation.

  10. A study of non-Keplerian velocities in observations of spectroscopic binary stars

    NASA Astrophysics Data System (ADS)

    Hearnshaw, J. B.; Komonjinda, Siramas; Skuljan, J.; Kilmartin, P. M.

    2012-11-01

    This paper presents an orbital analysis of six southern single-lined spectroscopic binary systems. The systems selected were shown to have circular or nearly circular orbits (e < 0.1) from earlier published solutions of only moderate precision. The purpose was to obtain high-precision orbital solutions in order to investigate the presence of small non-Keplerian velocity effects in the data and hence the reality of the small eccentricities found for most of the stars. The Hercules spectrograph and 1-m McLellan telescope at Mt John Observatory, New Zealand, were used to obtain over 450 CCD spectra between 2004 October and 2007 August. Radial velocities were obtained by cross-correlation. These data were used to achieve high-precision orbital solutions for all the systems studied, sometimes with solutions up to about 50 times more precise than those from the earlier literature. However, the precision of the solutions is limited in some cases by the rotational velocity or chromospheric activity of the stars. The data for the six binaries analysed here are combined with those for six stars analysed earlier by Komonjinda, Hearnshaw and Ramm. We have performed tests using the prescription of Lucy on all 12 binaries, and conclude that, with one exception, none of the small eccentricities found by fitting Keplerian orbits to the radial-velocity data can be supported. Instead we conclude that small non-Keplerian effects, which are clearly detectable for six of our stars, make impossible the precise determination of spectroscopic binary orbital eccentricities for many late-type stars to better than about 0.03 in eccentricity, unless the systematic perturbations are also carefully modelled. The magnitudes of the non-Keplerian velocity variations are given quantitatively.

  11. Optical effects related to Keplerian discs orbiting Kehagias-Sfetsos naked singularities

    NASA Astrophysics Data System (ADS)

    Stuchlík, Zdeněk; Schee, Jan

    2014-10-01

    We demonstrate possible optical signatures of the Kehagias-Sfetsos (KS) naked singularity spacetimes representing a spherically symmetric vacuum solution of the modified Hořava gravity. In such spacetimes, accretion structures significantly different from those present in standard black hole spacetimes occur due to the ‘antigravity’ effect, which causes an internal static sphere surrounded by Keplerian discs. We focus our attention on the optical effects related to the Keplerian accretion discs, constructing the optical appearance of the Keplerian discs, the spectral continuum due to their thermal radiation, and the spectral profiled lines generated in the innermost parts of such discs. The KS naked singularity signature is strongly encoded in the characteristics of predicted optical effects, especially in cases where the spectral continuum and spectral lines are profiled by the strong gravity of the spacetimes due to the vanishing region of the angular velocity gradient influencing the effectiveness of the viscosity mechanism. We can conclude that optical signatures of KS naked singularities can be well distinguished from the signatures of standard black holes.

  12. Post-Keplerian corrections to the orbital periods of a two-body system and their measurability

    NASA Astrophysics Data System (ADS)

    Iorio, L.

    2016-08-01

    The orbital motion of a binary system is characterized by various characteristic temporal intervals which, by definition, are different from each other: the draconitic, anomalistic and sidereal periods Tdra, Tano, Tsid. They all coincide in the Keplerian case. Such a degeneracy is removed, in general, when a post-Keplerian acceleration is present. We analytically work out the corrections T(pK) to such otherwise Keplerian periods which are induced by general relativity (Schwarzschild and Lense-Thirring) and, at the Newtonian level, by the quadrupole J2 of the primary. In many astronomical and astrophysical systems, like exoplanets, one of the most accurately determined quantities is just the time span Texp characterizing the orbital revolution, which is often measured independently with different techniques like the transit photometry and the radial velocities. Thus, our results could be useful, in principle, to either constrain the physical properties of the central body and/or perform new tests of general relativity, especially when no other standard observables like, e.g. the orbital precessions are accessible to observations. The difference ΔT of two independently measured periods would cancel out the common Keplerian term TK leaving just a post-Keplerian correction. Furthermore, by comparing the theoretically predicted post-Keplerian expressions T(pK) with the experimental accuracy σ _{T_exp} in measuring the orbital period(s) it is possible to identify those systems whose observations should be re-processed with genuine post-Keplerian models if T^{(pK)}>σ _{T_exp}. It seems just the case for WASP-33 b since σ _{T_exp}=0.04 s, while 3 s≤ T_dra^{(J_2)}≤ 9.5 s, T_dra^{(GR)}=0.36 s.

  13. Post-Keplerian corrections to the orbital periods of a two-body system and their measurability

    NASA Astrophysics Data System (ADS)

    Iorio, L.

    2016-08-01

    The orbital motion of a binary system is characterized by various characteristic temporal intervals which, by definition, are different from each other: the draconitic, anomalistic and sidereal periods. They all coincide in the Keplerian case. Such a degeneracy is removed, in general, when a post-Keplerian acceleration is present. We analytically work out the corrections to such otherwise Keplerian periods which are induced by general relativity (Schwarzschild and Lense-Thirring) and, at the Newtonian level, by the quadrupole of the primary. In many astronomical and astrophysical systems, like exoplanets, one of the most accurately determined quantities is just the time span characterizing the orbital revolution, which is often measured independently with different techniques like the transit photometry and the radial velocities. Thus, our results could be useful, in principle, to either constrain the physical properties of the central body and/or perform new tests of general relativity, especially when no other standard observables like, e.g., the orbital precessions are accessible to observations. The difference of two independently measured periods would cancel out the common Keplerian term leaving just a post-Keplerian correction. Furthermore, by comparing the theoretically predicted post-Keplerian expressions $T^{(\\textrm{pK})}$ with the experimental accuracy $\\sigma_{T_\\textrm{exp}}$ in measuring the orbital period(s) it is possible to identify those systems whose observations should be re-processed with genuine post-Keplerian models if $T^{(\\textrm{pK})}>\\sigma_{T_\\textrm{exp}}$. It seems just the case for WASP-33 b since $\\sigma_{T_\\textrm{exp}}=0.04$ s, while $3$ s$\\leq T_\\textrm{dra}^{(J_2)}\\leq 9.5$ s, $T_\\textrm{dra}^{(\\textrm{GE)}}=0.36$ s.

  14. PHYSICAL CHARACTERISTICS AND NON-KEPLERIAN ORBITAL MOTION OF 'PROPELLER' MOONS EMBEDDED IN SATURN'S RINGS

    SciTech Connect

    Tiscareno, Matthew S.; Burns, Joseph A.; Hedman, Matthew M.; Milano, Anthony J.; Evans, Michael W.; Sremcevic, Miodrag; Beurle, Kevin; Cooper, Nicholas J.; Porco, Carolyn C.; Spitale, Joseph N.; Weiss, John W.

    2010-08-01

    We report the discovery of several large 'propeller' moons in the outer part of Saturn's A ring, objects large enough to be followed over the 5 year duration of the Cassini mission. These are the first objects ever discovered that can be tracked as individual moons, but do not orbit in empty space. We infer sizes up to 1-2 km for the unseen moonlets at the center of the propeller-shaped structures, though many structural and photometric properties of propeller structures remain unclear. Finally, we demonstrate that some propellers undergo sustained non-Keplerian orbit motion.

  15. Keplerian Circumbinary Disk and Accretion Streams around the Protostellar Binary System L1551 NE

    NASA Astrophysics Data System (ADS)

    Takakuwa, S.; Saito, M.; Lim, J.; Saigo, K.; Hanawa, T.; Matsumoto, T.

    2013-10-01

    We show our recent observational results of L1551 NE, an archetypal binary protostellar system, in the 0.9-mm dust continuum emission and the C18O (J=3-2) emission with the SubMillimeter Array (SMA). The SMA results show firm evidence for a Keplerian circumbinary disk, circumstellar disks, and an inner clearing in the circumbinary disk, in L1551 NE. We demonstrate that future observations of L1551 NE with Atacama Large Millimeter and submillimeter Array (ALMA) have the potential to unveil the theoretically-predicted “accretion streams” that channel material from the circumbinary disk to the individual circumstellar disks.

  16. Numerical integration of nearly-Hamiltonian systems. [Van der Pol oscillator and perturbed Keplerian motion

    NASA Technical Reports Server (NTRS)

    Bond, V. R.

    1978-01-01

    The reported investigation is concerned with the solution of systems of differential equations which are derived from a Hamiltonian function in the extended phase space. The problem selected involves a one-dimensional perturbed harmonic oscillator. The van der Pol equation considered has an exact asymptotic value for its amplitude. Comparisons are made between a numerical solution and a known analytical solution. In addition to the van der Pol problem, known solutions regarding the restricted problem of three bodies are used as examples for perturbed Keplerian motion. The extended phase space Hamiltonian discussed by Stiefel and Scheifele (1971) is considered. A description is presented of two canonical formulations of the perturbed harmonic oscillator.

  17. On the Bound of Tschauner-Hempel Equations' Error with Respect to Keplerian Motion

    NASA Astrophysics Data System (ADS)

    Hu, Yong; Xie, Yongchun; Jiang, Tiantian

    2015-07-01

    This paper addresses theoretical analysis of the error of TH equations with respect to relative motion equations based on Keplerian orbits. By solving a second-order integral inequality, we derive a bound function of the error. The bound function depends on initial true anomaly, initial state error, eccentricity of target orbit, and current true anomaly. Using this result, we can easily calculate the moment of impulse for correction in a multi-impulsive elliptical rendezvous based on TH equations so as to guarantee the terminal relative position and velocity errors in certain ranges. The proposed result is also illustrated by simulations of elliptical rendezvous.

  18. Gravitational Rutherford scattering and Keplerian orbits for electrically charged bodies in heterotic string theory

    NASA Astrophysics Data System (ADS)

    Villanueva, J. R.; Olivares, Marco

    2015-11-01

    Properties of the motion of electrically charged particles in the background of the Gibbons-Maeda-Garfinkle-Horowitz-Strominger black hole is presented in this paper. Radial and angular motions are studied analytically for different values of the fundamental parameter. Therefore, gravitational Rutherford scattering and Keplerian orbits are analyzed in detail. Finally, this paper complements previous work by Fernando for null geodesics (Phys Rev D 85:024033, 2012), Olivares and Villanueva (Eur Phys J C 73:2659, 2013) and Blaga (Automat Comp Appl Math 22:41-48, 2013; Serb Astron 190:41, 2015) for time-like geodesics.

  19. No Keplerian Disk >10 AU Around the Protostar B335: Magnetic Braking or Young Age?

    NASA Astrophysics Data System (ADS)

    Yen, Hsi-Wei; Takakuwa, Shigehisa; Koch, Patrick M.; Aso, Yusuke; Koyamatsu, Shin; Krasnopolsky, Ruben; Ohashi, Nagayoshi

    2015-10-01

    We have conducted Atacama Large Millimeter/Submillimeter Array (ALMA) cycle 2 observations in the 1.3 mm continuum and in the C18O (2-1) and SO (56-45) lines at a resolution of ˜0.″3 toward the Class 0 protostar B335. The 1.3 mm continuum, C18O, and SO emission all show central compact components with sizes of ˜40-180 AU within more extended components. The C18O component shows signs of infalling and rotational motion. By fitting simple kinematic models to the C18O data, the protostellar mass is estimated to be 0.05 {M}⊙ . The specific angular momentum, on a 100 AU scale, is (4.3 ± 0.5) × 10-5 km s-1 pc. A similar specific angular momentum, (3-5) × 10-5 km s-1 pc, is measured on a 10 AU scale from the velocity gradient observed in the central SO component, and there is no clear sign of an infalling motion in the SO emission. By comparing the infalling and rotational motion, our ALMA results suggest that the observed rotational motion has not yet reached Keplerian velocity neither on a 100 AU nor even on a 10 AU scale. Consequently, the radius of the Keplerian disk in B335 (if present) is expected to be 1-3 AU. The expected disk radius in B335 is one to two orders of magnitude smaller than those of observed Keplerian disks around other Class 0 protostars. Based on the observed infalling and rotational motion from 0.1 pc to inner 100 AU scales, there are two possible scenarios to explain the presence of such a small Keplerian disk in B335: magnetic braking and young age. If our finding is the consequence of magnetic braking, ˜50% of the angular momentum of the infalling material within a 1000 AU scale might have been removed, and the magnetic field strength on a 1000 AU scale is estimated to be ˜200 μG. If it is young age, the infalling radius in B335 is estimated to be ˜2700 AU, corresponding to a collapsing timescale of ˜5 × 104 years.

  20. The APOGEE-1 Catalog of Keplerian Orbit Fits to RV Variable Sources

    NASA Astrophysics Data System (ADS)

    Troup, Nicholas W.; Nidever, David L.; Fleming, Scott W.; Deshpande, Rohit; Mahadevan, Suvrath; Wisniewski, John P.; Shetrone, Matthew D.; Roy, Arpita; De Lee, Nathan M.; Stassun, Keivan; Pepper, Joshua; Nguyen, Duy Cuong; Hearty, Fred; Sobeck, Jennifer; Majewski, Steven R.

    2015-01-01

    In its three years of operation, the Sloan Digital Sky Survey (SDSS-III) Apache Point Observatory Galactic Evolution Experiment (APOGEE-1) observed over 9000 stars which have a enough (≥7) unique, quality radial velocity measurements over a sufficient baseline to fit Keplerian orbits. In this catalog we present the best fit orbital parameters of these systems from our automated Keplerian orbit fitting pipeline. While many multiplicity and exoplanet surveys have focused on FGK dwarf stars and the solar neighborhood, our sample contains >3000 evolved stars (log g <3.5), as well as stars across the disk and into the halo. With a radial velocity precision of ~100 m/s, APOGEE can probe systems with close-in companions down to a few Jupiter-masses (10-3 M⊙). In particular, our sample is well suited to comb the elusive brown-dwarf desert. Additionally, stellar parameters and chemical abundances will be available for many of the primary stars in our sample, allowing us to further probe the connection between a host star's abundance and the presence of companions. Finally, we present some of our most interesting systems with detected companions, as well as initial follow-up observations for a subset of these systems.

  1. Canonical elements and Keplerian-like solutions for intermediary orbits of satellites of an oblate planet

    NASA Astrophysics Data System (ADS)

    Floria, Luis

    1993-10-01

    Within the framework of the Canonical Formalism in the extended phase space, a general Hamiltonian is investigated that covers a wide class of radial intermediaries accounting for the major secular effects due to a planet's oblateness perturbations. An analytical, closed-form solution for this generic Hamiltonian is developed in terms of elementary functions via the corresponding Hamilton-Jacobi equation. The analytical solution so obtained can be contemplated according to a simple geometrical and dynamical interpretation in Keplerian language by means of the usual relations characterizing elliptic elements along a hypothetic Keplerian motion. Appropriate choices for the terms appearing in the proposed Hamiltonian lead to recovering the analogs of some well-known, classical radial intermediaries (those introduced by Deprit and the one built by Alfriend and Coffey), but also certain new ones derived by Ferrandiz for the Main Problem in the Theory of Artificial Satellites of the Earth. In any case, the results are also applicable to problems dealing with orbital motion of other planetary satellites. The generality of this pattern leads to a systematic obtaining of solutions to the considered intermediaries: special choices of the Hamiltonian yield the corresponding analytical solution to the respective intermediary problem.

  2. ALMA observations of infalling flows toward the Keplerian disk around the class I protostar L1489 IRS

    SciTech Connect

    Yen, Hsi-Wei; Takakuwa, Shigehisa; Ohashi, Nagayoshi; Aikawa, Yuri; Aso, Yusuke; Koyamatsu, Shin; Machida, Masahiro N.; Saigo, Kazuya; Saito, Masao; Tomida, Kengo; Tomisaka, Kohji

    2014-09-20

    We have conducted ALMA observations in the 1.3 mm continuum and {sup 12}CO (2-1), C{sup 18}O (2-1), and SO (5{sub 6}-4{sub 5}) lines toward L1489 IRS, a Class I protostar surrounded by a Keplerian disk and an infalling envelope. The Keplerian disk is clearly identified in the {sup 12}CO and C{sup 18}O emission, and its outer radius (∼700 AU) and mass (∼0.005 M {sub ☉}) are comparable to those of disks around T Tauri stars. The protostellar mass is estimated to be 1.6 M {sub ☉} with the inclination angle of 66°. In addition to the Keplerian disk, there are blueshifted and redshifted off-axis protrusions seen in the C{sup 18}O emission pointing toward the north and the south, respectively, adjunct to the middle part of the Keplerian disk. The shape and kinematics of these protrusions can be interpreted as streams of infalling flows with a conserved angular momentum following parabolic trajectories toward the Keplerian disk, and the mass infalling rate is estimated to be ∼5 × 10{sup –7} M {sub ☉} yr{sup –1}. The specific angular momentum of the infalling flows (∼2.5 × 10{sup –3} km s{sup –1} pc) is comparable to that at the outer radius of the Keplerian disk (∼4.8 × 10{sup –3} km s{sup –1} pc). The SO emission is elongated along the disk major axis and exhibits a linear velocity gradient along the axis, which is interpreted to mean that the SO emission primarily traces a ring region in the flared Keplerian disk at radii of ∼250-390 AU. The local enhancement of the SO abundance in the ring region can be due to the accretion shocks at the centrifugal radius where the infalling flows fall onto the disk. Our ALMA observations unveiled both the Keplerian disk and the infalling gas onto the disk, and the disk can further grow by accreting material and angular momenta from the infalling gas.

  3. Linear and non-linear theory of a parametric instability of hydrodynamic warps in Keplerian discs

    NASA Astrophysics Data System (ADS)

    Gammie, Charles F.; Goodman, Jeremy; Ogilvie, Gordon I.

    2000-11-01

    We consider the stability of warping modes in Keplerian discs. We find them to be parametrically unstable using two lines of attack, one based on three-mode couplings and the other on Floquet theory. We confirm the existence of the instability and investigate its non-linear development in three dimensions, via numerical experiment. The most rapidly growing non-axisymmetric disturbances are the most nearly axisymmetric (low-m) ones. Finally, we offer a simple, somewhat speculative model for the interaction of the parametric instability with the warp. We apply this model to the masing disc in NGC 4258 and show that, provided the warp is not forced too strongly, parametric instability can fix the amplitude of the warp.

  4. Compensation of spatial dispersion of an acousto-optic deflector with a special Keplerian telescope.

    PubMed

    Hu, Qinglei; Zhou, Zhenqiao; Lv, Xiaohua; Zeng, Shaoqun

    2016-01-15

    Compensation of spatial dispersion caused by the acousto-optic deflector (AOD) when using a femtosecond laser is difficult across the whole scanning range of the system, and this is a significant impediment to its use. In conventional methods, the dispersion of the AOD was compensated only when it was at a particular position, while at other positions, the quality of the light beam was reduced. We developed a novel method for compensating the spatial dispersion within the entire scanning range using a special Keplerian telescope. Our experimental results show that the residual dispersion of the AOD is compensated sufficiently, and the focal spots of the laser reach the diffraction limit within a 40-MHz ultrasound bandwidth. PMID:26766675

  5. Classical Be stars. Rapidly rotating B stars with viscous Keplerian decretion disks

    NASA Astrophysics Data System (ADS)

    Rivinius, Thomas; Carciofi, Alex C.; Martayan, Christophe

    2013-10-01

    In the past decade, a consensus has emerged regarding the nature of classical Be stars: They are very rapidly rotating main sequence B stars, which, through a still unknown, but increasingly constrained process, form an outwardly diffusing gaseous, dust-free Keplerian disk. In this work, first the definition of Be stars is contrasted to similar classes, and common observables obtained for Be stars are introduced and the respective formation mechanisms explained. We then review the current state of knowledge concerning the central stars as non-radially pulsating objects and non-magnetic stars, as far as it concerns large-scale, i.e., mostly dipolar, global fields. Localized, weak magnetic fields remain possible, but are as of yet unproven. The Be-phenomenon, linked with one or more mass-ejection processes, acts on top of a rotation rate of about 75 % of critical or above. The properties of the process can be well constrained, leaving only few options, most importantly, but not exclusively, non-radial pulsation and small-scale magnetic fields. Of these, it is well possible that all are realized: In different stars, different processes may be acting. Once the material has been lifted into Keplerian orbit, memory of the details of the ejection process is lost, and the material is governed by viscosity. The disks are fairly well understood in the theoretical framework of the viscous decretion disk model. This is not only true for the disk structure, but as well for its variability, both cyclic and secular. Be binaries are reviewed under the aspect of the various types of interactions a companion can have with the circumstellar disk. Finally, extragalactic Be stars, at lower metallicities, seem more common and more rapidly rotating.

  6. Dark matter or new physics?. [deviation of galactic rotation curves from their expected Keplerian fall-off

    NASA Technical Reports Server (NTRS)

    Kazanas, Demosthenes; Mannheim, Philip D.

    1991-01-01

    Several proposals for a new physics to explain the deviation of galactic rotation curves from their expected Keplerian falloff with distance are discussed. Emphasis is given to a locally scale-invariant theory of gravity posed by the authors. The observational consequences of this theory are pointed out.

  7. Nonconservative extension of Keplerian integrals and a new class of integrable system

    NASA Astrophysics Data System (ADS)

    Roa, Javier

    2016-09-01

    The invariance of the Lagrangian under time translations and rotations in Kepler's problem yields the conservation laws related to the energy and angular momentum. Noether's theorem reveals that these same symmetries furnish generalized forms of the first integrals in a special nonconservative case, which approximates various physical models. The system is perturbed by a biparametric acceleration with components along the tangential and normal directions. A similarity transformation reduces the biparametric disturbance to a simpler uniparametric forcing along the velocity vector. The solvability conditions of this new problem are discussed, and closed-form solutions for the integrable cases are provided. Thanks to the conservation of a generalized energy, the orbits are classified as elliptic, parabolic, and hyperbolic. Keplerian orbits appear naturally as particular solutions to the problem. After characterizing the orbits independently, a unified form of the solution is built based on the Weierstrass elliptic functions. The new trajectories involve fundamental curves such as cardioids and logarithmic, sinusoidal, and Cotes' spirals. These orbits can represent the motion of particles perturbed by solar radiation pressure, of spacecraft with continuous thrust propulsion, and some instances of Schwarzschild geodesics. Finally, the problem is connected with other known integrable systems in celestial mechanics.

  8. Small Scale Chemical Segregation Within Keplerian Disk Candidate G35.20-0.74N

    NASA Astrophysics Data System (ADS)

    Allen, Veronica; van der Tak, Floris; Sánchez-Monge, Álvaro; Cesaroni, Riccardo; Beltrán, Maria T.

    2016-06-01

    In the study of high-mass star formation, hot cores are empirically defined stages where chemically rich emission is detected toward a massive protostar. It is unknown whether the physical origin of this emission is a disk, inner envelope, or outflow cavity wall and whether the hot core stage is common to all massive stars. With the advent of the highly sensitive sub-millimeter interferometer, ALMA, the ability to chemically characterize high mass star forming regions other than Orion has become possible. In the up-and-coming field of observational astrochemistry, these sensitive high resolution observations have opened up opportunities to find small scale variations in young protostellar sources.We have done an in depth analysis of high spatial resolution (~1000 AU) Cycle 0 ALMA observations of the high mass star forming region G35.20-0.74N, where Sánchez-Monge et al (2013) found evidence for Keplerian rotation. After further chemical analysis, numerous complex organic species have been identified in this region and we notice an interesting asymmetry in the distribution of the Nitrogen-bearing species within this source. In my talk, I will briefly outline the case for the disk and the consequences for this hypothesis following the chemical segregation we have seen.

  9. Extended analytical formulas for the perturbed Keplerian motion under a constant control acceleration

    NASA Astrophysics Data System (ADS)

    Zuiani, Federico; Vasile, Massimiliano

    2015-03-01

    This paper presents a set of analytical formulae for the perturbed Keplerian motion of a spacecraft under the effect of a constant control acceleration. The proposed set of formulae can treat control accelerations that are fixed in either a rotating or inertial reference frame. Moreover, the contribution of the zonal harmonic is included in the analytical formulae. It will be shown that the proposed analytical theory allows for the fast computation of long, multi-revolution spirals while maintaining good accuracy. The combined effect of different perturbations and of the shadow regions due to solar eclipse is also included. Furthermore, a simplified control parameterisation is introduced to optimise thrusting patterns with two thrust arcs and two cost arcs per revolution. This simple parameterisation is shown to ensure enough flexibility to describe complex low thrust spirals. The accuracy and speed of the proposed analytical formulae are compared against a full numerical integration with different integration schemes. An averaging technique is then proposed as an application of the analytical formulae. Finally, the paper presents an example of design of an optimal low-thrust spiral to transfer a spacecraft from an elliptical to a circular orbit around the Earth.

  10. Simplified solution for osculating Keplerian parameter corrections of GEO satellites for intersatellite optical link

    NASA Astrophysics Data System (ADS)

    Yılmaz, Umit C.; Cavdar, Ismail H.

    2015-04-01

    In intersatellite optical communication, the Pointing, Acquisition and Tracking (PAT) phase is one of the important phases that needs to be completed successfully before initiating communication. In this paper, we focused on correcting the possible errors on the Geostationary Earth Orbit (GEO) by using azimuth and elevation errors between Low Earth Orbit (LEO) to GEO optical link during the PAT phase. To minimise the PAT duration, a simplified correction of longitude and inclination errors of the GEO satellite's osculating Keplerian parameters has been suggested. A simulation has been done considering the beaconless tracking and spiral-scanning technique. As a result, starting from the second day, we are able to reduce the uncertainty cone of the GEO satellite by about 200 μrad, if the values are larger than that quantity. The first day of the LEO-GEO links have been used to determine the parameters. Thanks to the corrections, the locking time onto the GEO satellite has been reduced, and more data are able to transmit to the GEO satellite.

  11. Nonlinear hydrodynamical evolution of eccentric Keplerian discs in two dimensions: validation of secular theory

    NASA Astrophysics Data System (ADS)

    Barker, A. J.; Ogilvie, G. I.

    2016-06-01

    We perform global two-dimensional hydrodynamical simulations of Keplerian discs with free eccentricity over thousands of orbital periods. Our aim is to determine the validity of secular theory in describing the evolution of eccentric discs, and to explore their nonlinear evolution for moderate eccentricities. Linear secular theory is found to correctly predict the structure and precession rates of discs with small eccentricities. However, discs with larger eccentricities (and eccentricity gradients) are observed to precess faster (retrograde relative to the orbital motion), at a rate that depends on their eccentricities (and eccentricity gradients). We derive analytically a nonlinear secular theory for eccentric gas discs, which explains this result as a modification of the pressure forces whenever eccentric orbits in a disc nearly intersect. This effect could be particularly important for highly eccentric discs produced in tidal disruption events, or for narrow gaseous rings; it might also play a role in causing some of the variability in superhump binary systems. In two dimensions, the eccentricity of a moderately eccentric disc is long-lived and persists throughout the duration of our simulations. Eccentric modes are however weakly damped by their interaction with non-axisymmetric spiral density waves (driven by the Papaloizou-Pringle instability, which occurs in our idealized setup with solid walls), as well as numerical diffusion.

  12. PROPERTIES AND KEPLERIAN ROTATION OF THE HOT CORE IRAS 20126+4104

    SciTech Connect

    Xu Jinlong; Wang Junjie; Ning Changchun

    2012-01-10

    We present Submillimeter Array (SMA) observations of the massive star-forming region IRAS 20126+4104 in the millimeter continuum and in several molecular line transitions. With the SMA data, we have detected nine molecular transitions, including deuterated hydrogen cyanide, CH{sub 3}OH, H{sub 2}CO, and HC{sub 3}N molecules, and imaged each molecular line. From the 1.3 mm continuum emission a compact millimeter source is revealed, which is also associated with H{sub 2}O, OH, and CH{sub 3}OH masers. Using a rotation temperature diagram, we derive that the rotational temperature and the column density of CH{sub 3}OH are 200 K and 3.7 Multiplication-Sign 10{sup 17} cm{sup -2}, respectively. The calculated results and analysis further indicate that a hot core coincides with IRAS 20126+4104. The position-velocity diagrams of H{sub 2}CO (3{sub 0,3}-2{sub 0,2}) and HC{sub 3}N (25-24) clearly present Keplerian rotation. Moreover, H{sub 2}CO (3{sub 0,3}-2{sub 0,2}) is found to trace the disk rotation for the first time.

  13. ALMA Observations of the Transition from Infall Motion to Keplerian Rotation around the Late-phase Protostar TMC-1A

    NASA Astrophysics Data System (ADS)

    Aso, Yusuke; Ohashi, Nagayoshi; Saigo, Kazuya; Koyamatsu, Shin; Aikawa, Yuri; Hayashi, Masahiko; Machida, Masahiro N.; Saito, Masao; Takakuwa, Shigehisa; Tomida, Kengo; Tomisaka, Kohji; Yen, Hsi-Wei

    2015-10-01

    We have observed the Class I protostar TMC-1A with the Atacama Millimeter/submillimeter Array (ALMA) in the emissions of 12CO and C18O (J = 2–1) and 1.3 mm dust continuum. Continuum emission with a deconvolved size of 0.″50 × 0.″37, perpendicular to the 12CO outflow, is detected. It most likely traces a circumstellar disk around TMC-1A, as previously reported. In contrast, a more extended structure is detected in C18O, although it is still elongated with a deconvolved size of 3.″3 × 2.″2, indicating that C18O traces mainly a flattened envelope surrounding the disk and the central protostar. C18O shows a clear velocity gradient perpendicular to the outflow at higher velocities, indicative of rotation, while an additional velocity gradient along the outflow is found at lower velocities. The radial profile of the rotational velocity is analyzed in detail, finding that it is given as a power law ∝r‑a with an index of ∼0.5 at higher velocities. This indicates that the rotation at higher velocities can be explained as Keplerian rotation orbiting a protostar with a dynamical mass of 0.68 {M}ȯ (inclination corrected). The additional velocity gradient of C18O along the outflow is considered to be mainly infall motions in the envelope. Position–velocity diagrams made from models consisting of an infalling envelope and a Keplerian disk are compared with the observations, revealing that the observed infall velocity is ∼0.3 times smaller than the free-fall velocity yielded by the dynamical mass of the protostar. Magnetic fields could be responsible for the slow infall velocity. A possible scenario of Keplerian disk formation is discussed.

  14. Unique Non-Keplerian Orbit Vantage Locations for Sun-Earth Connection and Earth Science Vision Roadmaps

    NASA Technical Reports Server (NTRS)

    Folta, David; Young, Corissa; Ross, Adam

    2001-01-01

    The purpose of this investigation is to determine the feasibility of attaining and maintaining unique non-Keplerian orbit vantage locations in the Earth/Moon environment in order to obtain continuous scientific measurements. The principal difficulty associated with obtaining continuous measurements is the temporal nature of astrodynamics, i.e., classical orbits. This investigation demonstrates advanced trajectory designs to meet demanding science requirements which cannot be met following traditional orbital mechanic logic. Examples of continuous observer missions addressed include Earth pole-sitters and unique vertical libration orbits that address Sun-Earth Connection and Earth Science Vision roadmaps.

  15. Reynolds number scaling of the influence of boundary layers on the global behavior of laboratory quasi-Keplerian flows

    DOE PAGESBeta

    Edlund, E. M.; Ji, H.

    2015-10-06

    Here, we present fluid velocity measurements in a modified Taylor-Couette device operated in the quasi-Keplerian regime, where it is observed that nearly ideal flows exhibit self-similarity under scaling of the Reynolds number. In contrast, nonideal flows show progressive departure from ideal Couette as the Reynolds number is increased. We present a model that describes the observed departures from ideal Couette rotation as a function of the fluxes of angular momentum across the boundaries, capturing the dependence on Reynolds number and boundary conditions.

  16. Reynolds number scaling of the influence of boundary layers on the global behavior of laboratory quasi-Keplerian flows

    SciTech Connect

    Edlund, E. M.; Ji, H.

    2015-10-01

    We present fluid velocity measurements in a modified Taylor-Couette device operated in the quasi-Keplerian regime, where it is observed that nearly ideal flows exhibit self-similarity under scaling of the Reynolds number. In contrast, nonideal flows show progressive departure from ideal Couette as the Reynolds number is increased. We present a model that describes the observed departures from ideal Couette rotation as a function of the fluxes of angular momentum across the boundaries, capturing the dependence on Reynolds number and boundary conditions.

  17. Background oriented schlieren in a density stratified fluid.

    PubMed

    Verso, Lilly; Liberzon, Alex

    2015-10-01

    Non-intrusive quantitative fluid density measurement methods are essential in the stratified flow experiments. Digital imaging leads to synthetic schlieren methods in which the variations of the index of refraction are reconstructed computationally. In this study, an extension to one of these methods, called background oriented schlieren, is proposed. The extension enables an accurate reconstruction of the density field in stratified liquid experiments. Typically, the experiments are performed by the light source, background pattern, and the camera positioned on the opposite sides of a transparent vessel. The multimedia imaging through air-glass-water-glass-air leads to an additional aberration that destroys the reconstruction. A two-step calibration and image remapping transform are the key components that correct the images through the stratified media and provide a non-intrusive full-field density measurements of transparent liquids. PMID:26520964

  18. Background oriented schlieren in a density stratified fluid

    NASA Astrophysics Data System (ADS)

    Verso, Lilly; Liberzon, Alex

    2015-10-01

    Non-intrusive quantitative fluid density measurement methods are essential in the stratified flow experiments. Digital imaging leads to synthetic schlieren methods in which the variations of the index of refraction are reconstructed computationally. In this study, an extension to one of these methods, called background oriented schlieren, is proposed. The extension enables an accurate reconstruction of the density field in stratified liquid experiments. Typically, the experiments are performed by the light source, background pattern, and the camera positioned on the opposite sides of a transparent vessel. The multimedia imaging through air-glass-water-glass-air leads to an additional aberration that destroys the reconstruction. A two-step calibration and image remapping transform are the key components that correct the images through the stratified media and provide a non-intrusive full-field density measurements of transparent liquids.

  19. Formation of a Keplerian Disk in the Infalling Envelope around L1527 IRS: Transformation from Infalling Motions to Kepler Motions

    NASA Astrophysics Data System (ADS)

    Ohashi, Nagayoshi; Saigo, Kazuya; Aso, Yusuke; Aikawa, Yuri; Koyamatsu, Shin; Machida, Masahiro N.; Saito, Masao; Takahashi, Sanemichi Z.; Takakuwa, Shigehisa; Tomida, Kengo; Tomisaka, Kohji; Yen, Hsi-Wei

    2014-12-01

    We report Atacama Large Millimeter/submillimeter Array (ALMA) cycle 0 observations of the C18O (J = 2-1), SO (JN = 65-54), and the 1.3 mm dust continuum toward L1527 IRS, a class 0 solar-type protostar surrounded by an infalling and rotating envelope. C18O emission shows strong redshifted absorption against the bright continuum emission associated with L1527 IRS, strongly suggesting infall motions in the C18O envelope. The C18O envelope also rotates with a velocity mostly proportional to r -1, where r is the radius, whereas the rotation profile at the innermost radius (~54 AU) may be shallower than r -1, suggestive of formation of a Keplerian disk around the central protostar of ~0.3 M ⊙ in dynamical mass. SO emission arising from the inner part of the C18O envelope also shows rotation in the same direction as the C18O envelope. The rotation is, however, rigid-body-like, which is very different from the differential rotation shown by C18O. In order to explain the line profiles and the position-velocity (PV) diagrams of C18O and SO observed, simple models composed of an infalling envelope surrounding a Keplerian disk of 54 AU in radius orbiting a star of 0.3 M ⊙ are examined. It is found that in order to reproduce characteristic features of the observed line profiles and PV diagrams, the infall velocity in the model has to be smaller than the free-fall velocity yielded by a star of 0.3 M ⊙. Possible reasons for the reduced infall velocities are discussed.

  20. Non-Keplerian effects in precision radial velocity measurements of double-line spectroscopic binary stars: numerical simulations

    NASA Astrophysics Data System (ADS)

    Sybilski, P.; Konacki, M.; Kozłowski, S. K.; Hełminiak, K. G.

    2013-05-01

    Current precision in radial velocity (RV) measurements of binary stars reaches ˜2 m s-1. This level of precision means that RV models have to take into account additional non-Keplerian effects such as tidal and rotational distortion of the components of a binary star, relativistic effects and orbital precession. Such an approach is necessary when one wants to search for planets or precisely measure fundamental parameters of stars with a very high accuracy using precision RVs of binary stars. We generate synthetic binaries using Yonsei-Yale stellar models. For typical representatives, we investigate the impact of various orbital orientations and different non-Keplerian effects on the RV curves. To this end, we simulate RV observations with an added white noise of different scale. Subsequently, we try to reconstruct the input orbital parameters and their errors by fitting a model using a standard least-squares method. In particular, we investigate the connection between the tidal distortion of the shape of the stars and the best-fitting orbital eccentricity; the possibility of deriving orbital inclination of a non-eclipsing binary star by exploiting relativistic effects and the circumstances in which the orbital precession can be detected. We confirm that the method proposed by Zucker & Alexander to obtain orbital inclination with use of the relativistic effect does work in favourable cases and that it can be used even for orbital configurations far from an edge-on orientation. We show that the RV variations imposed by tidally distorted stars can mimic non-zero eccentricity in some binaries. The scale of such an effect depends on the RV accuracy. Finally, we demonstrate that the apsidal precession can be easily detected with precision RVs. In particular, we can detect orbital precession of 10-4, 10-3 rad yr-1 for precision of RVs of 1 and 10 m s-1, respectively.

  1. Formation of a Keplerian disk in the infalling envelope around L1527 IRS: transformation from infalling motions to Kepler motions

    SciTech Connect

    Ohashi, Nagayoshi; Saigo, Kazuya; Aso, Yusuke; Koyamatsu, Shin; Aikawa, Yuri; Machida, Masahiro N.; Saito, Masao; Takahashi, Sanemichi Z.; Takakuwa, Shigehisa; Yen, Hsi-Wei; Tomida, Kengo; Tomisaka, Kohji

    2014-12-01

    We report Atacama Large Millimeter/submillimeter Array (ALMA) cycle 0 observations of the C{sup 18}O (J = 2-1), SO (J{sub N} = 6{sub 5}-5{sub 4}), and the 1.3 mm dust continuum toward L1527 IRS, a class 0 solar-type protostar surrounded by an infalling and rotating envelope. C{sup 18}O emission shows strong redshifted absorption against the bright continuum emission associated with L1527 IRS, strongly suggesting infall motions in the C{sup 18}O envelope. The C{sup 18}O envelope also rotates with a velocity mostly proportional to r {sup –1}, where r is the radius, whereas the rotation profile at the innermost radius (∼54 AU) may be shallower than r {sup –1}, suggestive of formation of a Keplerian disk around the central protostar of ∼0.3 M {sub ☉} in dynamical mass. SO emission arising from the inner part of the C{sup 18}O envelope also shows rotation in the same direction as the C{sup 18}O envelope. The rotation is, however, rigid-body-like, which is very different from the differential rotation shown by C{sup 18}O. In order to explain the line profiles and the position-velocity (PV) diagrams of C{sup 18}O and SO observed, simple models composed of an infalling envelope surrounding a Keplerian disk of 54 AU in radius orbiting a star of 0.3 M {sub ☉} are examined. It is found that in order to reproduce characteristic features of the observed line profiles and PV diagrams, the infall velocity in the model has to be smaller than the free-fall velocity yielded by a star of 0.3 M {sub ☉}. Possible reasons for the reduced infall velocities are discussed.

  2. A new inclination instability reshapes Keplerian discs into cones: application to the outer Solar system

    NASA Astrophysics Data System (ADS)

    Madigan, Ann-Marie; McCourt, Michael

    2016-03-01

    Discs of bodies orbiting a much more massive central object are extremely common in astrophysics. When the orbits comprising such discs are eccentric, we show they are susceptible to a new dynamical instability. Gravitational forces between bodies in the disc drive exponential growth of their orbital inclinations and clustering in their angles of pericentre, expanding an initially thin disc into a conical shape by giving each orbit an identical `tilt' with respect to the disc plane. This new instability dynamically produces the unusual distribution of orbits observed for minor planets beyond Neptune, suggesting that the instability has shaped the outer Solar system. It also implies a large disc mass (˜ 1-10 Earth masses) of scattered bodies at hundreds of AU; we predict increasing numbers of detections of minor planets clustered in their angles of pericentre with high inclinations.

  3. A Comparison of SPH Artificial Viscosities and Their Impact on the Keplerian Disk

    NASA Astrophysics Data System (ADS)

    Hosono, Natsuki; Saitoh, Takayuki R.; Makino, Junichiro

    2016-06-01

    Hydrodynamical simulations of rotating disks play important roles in the field of astrophysical and planetary science. Smoothed particle hydrodynamics (SPH) has been widely used for such simulations. However, it has been known that when using SPH, a cold and thin Kepler disk breaks up due to the unwanted angular momentum transfer. Two possible reasons have been suggested for this breaking up of the disk; the artificial viscosity (AV) and the numerical error in the evaluation of pressure gradient in SPH. Which one is dominant is still unclear. In this paper, we investigate the reason for this rapid breaking up of the disk. We implemented most of the popular formulations of AV and switches, and measured the angular momentum transfer due to both AV and the error of SPH’s estimate of the pressure gradient. We found that the angular momentum transfer due to AV at the inner edge triggers the breaking up of the disk. We also found that the classical von Neumann–Richtmyer–Landshoff type AV with a high-order estimate for {{\

  4. PLANETESIMAL FORMATION AT THE BOUNDARY BETWEEN STEADY SUPER/SUB-KEPLERIAN FLOW CREATED BY INHOMOGENEOUS GROWTH OF MAGNETOROTATIONAL INSTABILITY

    SciTech Connect

    Kato, M. T.; Ida, S.; Fujimoto, M.

    2012-03-01

    We have studied formation of planetesimals at a radial pressure bump in a protoplanetary disk created by radially inhomogeneous magnetorotational instability (MRI), through three-dimensional resistive MHD simulations including dust particles. In our previous papers, we showed that the inhomogeneous MRI developing in non-uniform structure of magnetic field or magnetic resistivity can transform the local gas flow in the disk to a quasi-steady state with local rigid rotation that is no longer unstable against the MRI. Since the outer part of the rigid rotation is super-Keplerian flow, a quasi-static pressure bump is created and dust concentration is expected there. In this paper, we perform simulations of the same systems, adding dust particles that suffer gas drag and modulate gas flow via the back-reaction of the gas drag (dust drag). We use {approx}O(10{sup 7}) super-particles, each of which represents {approx}O(10{sup 6})-O(10{sup 7}) dust particles with sizes of centimeter to meter. We have found that the dust drag suppresses turbulent motion to decrease the velocity dispersion of the dust particles while it broadens the dust concentrated regions to limit peaky dust concentration, compared with the simulation without the dust drag. We found that the positive effect for the gravitational instability (GI), reduction in the velocity dispersion, dominates over the negative one, suppression in particle concentration. For meter-size particles with the friction time {tau}{sub f} {approx_equal} 1/{Omega}, where {Omega} is Keplerian frequency, the GI of the dust particles that may lead to planetesimal formation is expected. For such a situation, we further introduced the self-gravity of dust particles to the simulation to demonstrate that several gravitationally bound clumps are actually formed. Through analytical arguments, we found that planetesimal formation from meter-sized dust particles is possible at {approx}5 AU, if dust spatial density is a few times larger than

  5. Stability of an accretion disk: nonlinear small-scale analysis of a quasi-Keplerian shear flow

    NASA Astrophysics Data System (ADS)

    Miquel, Benjamin; Knobloch, Edgar; Julien, Keith

    2015-11-01

    We model the background flow in the equatorial plane of an accretion disk with a radially stratified, non-magnetic zonal flow in a quasi-Keplerian balance (i.e. small pressure corrections are taken into account in the radial balance). The dynamics of the perturbations around this background flow obey a set of equations which main ingredients are: (i) a radial shear, (ii) a radial stratification, and (iii) a coupling between the flow and the background entropy gradient. The inviscid linear stability of this set of equation is first discussed: perturbations are decomposed into Kelvin modes (also known as the shearing sheet approximation) which amplitudes are determined analytically as a function of the radial stratification. Then, using as well a Kelvin modes decomposition, the viscous linear problem exhibits potentially transient growth, yet features unconditional stability as t --> ∞ . Finally, we demonstrate with 2D simulations of the viscous nonlinear problem that nonlinearities provide an energy transfer mechanism through modes that compensates the transfer induced by the linear shear. This mechanism allows for a sustained instability scenario despite the stability of the linear viscous problem.

  6. DUST CONCENTRATION AT THE BOUNDARY BETWEEN STEADY SUPER/SUB-KEPLERIAN FLOW CREATED BY INHOMOGENEOUS GROWTH OF MAGNETO-ROTATIONAL INSTABILITY

    SciTech Connect

    Kato, M. T.; Ida, S.; Fujimoto, M.

    2010-05-10

    How planetesimals are created from tiny dust particles in a proto-planetary disk before the dust particles spiral to the central star is one of the most challenging problems in the theory of planetary system formation. In our previous paper, we have shown that a steady angular velocity profile that consists of both super- and sub-Keplerian regions is created in the disk through non-uniform excitation of magneto-rotational instability (MRI). Such non-uniform MRI excitation is reasonably expected in a part of disks with relatively low ionization degree. In this paper, we show through three-dimensional resistive MHD simulations with test particles that this radial structure of the angular velocity indeed leads to the prevention of spiral-in of dust particles and furthermore to their accumulation at the boundary of super-Keplerian and sub-Keplerian regions. Treating dust particles as test particles, their motions under the influence of the non-uniform MRI through gas drag are simulated. In the most favorable cases (meter-size dust particles in the disk region with a relatively large fraction of MRI-stable region), we found that the dust concentration is peaked around the super/sub-Keplerian flow boundary and the peak dust density is 10,000 times as high as the initial value. The peak density is high enough for the subsequent gravitational instability to set in, suggesting a possible route to planetesimal formation via non-uniformly excited MRI in weakly ionized regions of a disk.

  7. Planetary Companions to HD 12661, HD 92788, and HD 38529 and Variations in Keplerian Residuals of Extrasolar Planets

    NASA Astrophysics Data System (ADS)

    Fischer, Debra A.; Marcy, Geoffrey W.; Butler, R. Paul; Vogt, Steven S.; Frink, Sabine; Apps, Kevin

    2001-04-01

    Precision Doppler observations at the Lick and Keck observatories have revealed Keplerian velocity variations in the stars HD 12661, HD 92788, and HD 38529. HD 12661 (G6 V) has an orbital period of 252.7+/-2.7 days, velocity semiamplitude K=88.4+/-2.0 m s-1, and orbital eccentricity e=0.23+/-0.024. Adopting a stellar mass of 1.07 Msolar, we infer a companion mass of Msini=2.79 MJ and a semimajor axis of a=0.79 AU. HD 92788 (G5 V) has an orbital period of 326.7+/-3.2 days, velocity semiamplitude K=99.9+/-2.4, and orbital eccentricity e=0.30+/-0.06. The adopted stellar mass of 1.06 Msolar yields a companion mass of Msini=3.34 MJ and a semimajor axis of a=0.95 AU. HD 38529 (G4 IV) has an orbital period of 14.3+/-0.8 days, velocity semiamplitude K=53.8+/-2.0 m s-1, and eccentricity e=0.27+/-0.03. The stellar mass of 1.4 Msolar sets Msini=0.77 MJ, with a semimajor axis of a=0.13 AU for this companion. In addition to the 14.3 day periodicity, the velocity residuals for HD 38529 show curvature over the three years of observations. Based on a measurement of Ca II H and K emission, all three stars are chromospherically inactive. Based on both spectral synthesis modeling and narrowband photometry, HD 12661, HD 92788, and HD 38529 all appear to be metal-rich stars, reinforcing the correlation of high metallicity in the host stars of gas giant extrasolar planets. We examine the velocity residuals to the Keplerian fits for a subsample of 12 planet-bearing stars that have been observed longer than two years at the Lick Observatory. Five of the 12 (Ups Andromedae, τ Boo, 55 Cnc, HD 217107, and HD 38529) exhibit coherent variations in the residual velocities that are consistent with additional companions. Except for Upsilon Andromedae, the source of the velocity variation remains speculative pending completion of one full orbit. GJ 876 exhibits residual velocities with high rms scatter (24 m s-1), lacking identifiable coherence. The residual velocities for six of the 12 stars (51

  8. Tsien's method for generating non-Keplerian trajectories. Part 2: The question of thrust to orbit a sphere and the restricted three-body problem

    NASA Technical Reports Server (NTRS)

    Murad, P. A.

    1993-01-01

    Tsien's method is extended to treat the orbital motion of a body undergoing accelerations and decelerations. A generalized solution is discussed for the generalized case where a body undergoes azimuthal and radial thrust and the problem is further simplified for azimuthal thrust alone. Judicious selection of thrust could generate either an elliptic or hyperbolic trajectory. This is unexpected especially when the body has only enough energy for a lower state trajectory. The methodology is extended treating the problem of vehicle thrust for orbiting a sphere and vehicle thrust within the classical restricted three-body problem. Results for the latter situation can produce hyperbolic trajectories through eigen value decomposition. Since eigen values for no-thrust can be imaginary, thrust can generate real eigen values to describe hyperbolic trajectories. Keplerian dynamics appears to represent but a small subset of a much larger non-Keplerian domain especially when thrust effects are considered. The need for high thrust long duration space-based propulsion systems for changing a trajectory's canonical form is clearly demonstrated.

  9. Profiled spectral lines generated by Keplerian discs orbiting in the Bardeen and Ayòn-Beato-Garcìa spacetimes

    NASA Astrophysics Data System (ADS)

    Schee, Jan; Stuchlík, Zdeněk

    2016-04-01

    Shape and frequency-shift maps of direct and indirect images of Keplerian discs orbiting in Bardeen and Ayòn-Beato-Garcìa (ABG) black hole and no-horizon spacetimes are determined. Then profiles of spectral lines generated in the innermost parts of the Keplerian discs in the Bardeen and ABG spacetimes are constructed. The frequency-shift maps and profiled spectral lines are compared to those generated in the field of Schwarzschild black holes and possible observationally relevant signatures of the regular black hole and no-horizon spacetimes are discussed. We demonstrate that differences relative to the Schwarzschild spacetimes are for the no-horizon spacetimes much more profound in comparison to the regular black hole spacetimes and increase with increasing charge parameter of the spacetime. The differences are greater for small and large inclination angles than for intermediate ones. For the no-horizon spacetimes, the differences enable us to distinguish the Bardeen and ABG spacetime, if inclination angle to the distant observer is known. We also show that contribution of the so-called ghost images to the profiled lines increases with increasing charge parameter of the spacetimes.

  10. Closed-Form and Numerically-Stable Solutions to Problems Related to the Optimal Two-Impulse Transfer Between Specified Terminal States of Keplerian Orbits

    NASA Technical Reports Server (NTRS)

    Senent, Juan

    2011-01-01

    The first part of the paper presents some closed-form solutions to the optimal two-impulse transfer between fixed position and velocity vectors on Keplerian orbits when some constraints are imposed on the magnitude of the initial and final impulses. Additionally, a numerically-stable gradient-free algorithm with guaranteed convergence is presented for the minimum delta-v two-impulse transfer. In the second part of the paper, cooperative bargaining theory is used to solve some two-impulse transfer problems when the initial and final impulses are carried by different vehicles or when the goal is to minimize the delta-v and the time-of-flight at the same time.

  11. Nondissipative saturation of the magnetorotational instability in thin disks.

    PubMed

    Liverts, Edward; Shtemler, Yuri; Mond, Michael; Umurhan, Orkan M; Bisikalo, Dmitry V

    2012-11-30

    A new nondissipative mechanism is proposed for the saturation of the axisymmetric magnetorotational (MRI) instability in thin Keplerian disks that are subject to an axial magnetic field. That mechanism relies on the energy transfer from the MRI to stable magnetosonic waves. Such mode interaction is enabled due to the vertical stratification of the disk that results in the discretization of its MRI spectrum, as well as by applying the appropriate boundary conditions. A second order Duffing-like amplitude equation for the initially unstable MRI modes is derived. The solutions of that equation exhibit bursty nonlinear oscillations with a constant amplitude that signifies the saturation level of the MRI. Those results are verified by a direct numerical solution of the full nonlinear reduced set of thin disk magnetohydrodynamics equations. PMID:23368127

  12. Filamentary structure and Keplerian rotation in the high-mass star-forming region G35.03+0.35 imaged with ALMA

    NASA Astrophysics Data System (ADS)

    Beltrán, M. T.; Sánchez-Monge, Á.; Cesaroni, R.; Kumar, M. S. N.; Galli, D.; Walmsley, C. M.; Etoka, S.; Furuya, R. S.; Moscadelli, L.; Stanke, T.; van der Tak, F. F. S.; Vig, S.; Wang, K.-S.; Zinnecker, H.; Elia, D.; Schisano, E.

    2014-11-01

    Context. Theoretical scenarios propose that high-mass stars are formed by disk-mediated accretion. Aims: To test the theoretical predictions on the formation of massive stars, we wish to make a thorough study at high-angular resolution of the structure and kinematics of the dust and gas emission toward the high-mass star-forming region G35.03+0.35, which harbors a disk candidate around a B-type (proto)star. Methods: We carried out ALMA Cycle 0 observations at 870 μm of dust of typical high-density, molecular outflow, and cloud tracers with resolutions of < 0''&dotbelow;5. Complementary Subaru COMICS 25 μm observations were carried out to trace the mid-infrared emission toward this star-forming region. Results: The submillimeter continuum emission has revealed a filamentary structure fragmented into six cores, called A-F. The filament could be in quasi-equilibrium taking into account that the mass per unit length of the filament, 200-375 M⊙/pc, is similar to the critical mass of a thermally and turbulently supported infinite cylinder, ~335 M⊙/pc. The cores, which are on average separated by ~0.02 pc, have deconvolved sizes of 1300-3400 AU, temperatures of 35-240 K, H2 densities >107 cm -3, and masses in the range 1-5 M⊙, and they are subcritical. Core A, which is associated with a hypercompact Hii region and could be the driving source of the molecular outflow observed in the region, is the most chemically rich source in G35.03+0.35 with strong emission of typical hot core tracers such as CH3CN. Tracers of high density and excitation show a clear velocity gradient along the major axis of the core, which is consistent with a disk rotating about the axis of the associated outflow. The PV plots along the SE-NW direction of the velocity gradient show clear signatures of Keplerian rotation, although infall could also be present, and they are consistent with the pattern of an edge-on Keplerian disk rotating about a star with a mass in the range 5-13 M⊙. The high

  13. Magnetically Torqued Thin Accretion Disks

    NASA Astrophysics Data System (ADS)

    Kluźniak, W.; Rappaport, S.

    2007-12-01

    We compute the properties of a geometrically thin, steady accretion disk surrounding a central rotating, magnetized star. The magnetosphere is assumed to entrain the disk over a wide range of radii. The model is simplified in that we adopt two (alternate) ad hoc, but plausible, expressions for the azimuthal component of the magnetic field as a function of radial distance. We find a solution for the angular velocity profile tending to corotation close to the central star and smoothly matching a Keplerian curve at a radius where the viscous stress vanishes. The value of this ``transition'' radius is nearly the same for both of our adopted B-field models. We then solve analytically for the torques on the central star and for the disk luminosity due to gravity and magnetic torques. When expressed in a dimensionless form, the resulting quantities depend on one parameter alone, the ratio of the transition radius to the corotation radius. For rapid rotators, the accretion disk may be powered mostly by spin-down of the central star. These results are independent of the viscosity prescription in the disk. We also solve for the disk structure for the special case of an optically thick alpha disk. Our results are applicable to a range of astrophysical systems including accreting neutron stars, intermediate polar cataclysmic variables, and T Tauri systems.

  14. EXTREMELY LARGE AND HOT MULTILAYER KEPLERIAN DISK AROUND THE O-TYPE PROTOSTAR W51N: THE PRECURSORS OF THE HCH II REGIONS?

    SciTech Connect

    Zapata, Luis A.; Tang, Ya-Wen; Leurini, Silvia

    2010-12-10

    We present sensitive high angular resolution (0.''57-0.''78) SO, SO{sub 2}, CO, C{sub 2}H{sub 5}OH, HC{sub 3}N, and HCOCH{sub 2}OH line observations at millimeter and submillimeter wavelengths of the young O-type protostar W51 North made with the Submillimeter Array. We report the presence of a large (about 8000 AU) and hot molecular circumstellar disk around this object, which connects the inner dusty disk with the molecular ring or toroid reported recently and confirms the existence of a single bipolar outflow emanating from this object. The molecular emission from the large disk is observed in layers with the transitions characterized by high excitation temperatures in their lower energy states (up to 1512 K) being concentrated closer to the central massive protostar. The molecular emission from those transitions with low or moderate excitation temperatures is found in the outermost parts of the disk and exhibits an inner cavity with an angular size of around 0.''7. We modeled all lines with a local thermodynamic equilibrium (LTE) synthetic spectrum. A detailed study of the kinematics of the molecular gas together with an LTE model of a circumstellar disk shows that the innermost parts of the disk are also Keplerian plus a contracting velocity. The emission of the HCOCH{sub 2}OH reveals the possible presence of a warm 'companion' located to the northeast of the disk, however its nature is unclear. The emission of the SO and SO{sub 2} is observed in the circumstellar disk as well as in the outflow. We suggest that the massive protostar W51 North appears to be in a phase before the presence of a hypercompact or an ultracompact H II (HC/UCH II) region and propose a possible sequence on the formation of the massive stars.

  15. The Comparison of the Classical Keplerian Orbit Elements, Non-Singular Orbital Elements (Equinoctial Elements), and the Cartesian State Variables in Lagrange Planetary Equations with J2 Perturbation: Part I

    NASA Astrophysics Data System (ADS)

    Jo, Jung Hyun; Park, In Kwan; Choe, Nammi; Choi, Mansoo

    2011-03-01

    Two semi-analytic solutions for a perturbed two-body problem known as Lagrange planetary equations (LPE) were compared to a numerical integration of the equation of motion with same perturbation force. To avoid the critical conditions inherited from the configuration of LPE, non-singular orbital elements (EOE) had been introduced. In this study, two types of orbital elements, classical Keplerian orbital elements (COE) and EOE were used for the solution of the LPE. The effectiveness of EOE and the discrepancy between EOE and COE were investigated by using several near critical conditions. The near one revolution, one day, and seven days evolutions of each orbital element described in LPE with COE and EOE were analyzed by comparing it with the directly converted orbital elements from the numerically integrated state vector in Cartesian coordinate. As a result, LPE with EOE has an advantage in long term calculation over LPE with COE in case of relatively small eccentricity.

  16. Thin Clouds

    Atmospheric Science Data Center

    2013-04-18

    ... of this montage is a natural-color view of the Caribbean Sea east of the Yucatan Peninsula as seen by MISR's most steeply ... - Thin, feathery clouds of ice crystals over the Caribbean Sea. project:  MISR category:  gallery ...

  17. Thin Film?

    NASA Astrophysics Data System (ADS)

    Kariper, İ. Afşin

    2014-09-01

    This study focuses on the critical surface tension of lead sulfite (PbSO3) crystalline thin film produced with chemical bath deposition on substrates (commercial glass).The PbSO3 thin films were deposited at room temperature at different deposition times. The structural properties of the films were defined and examined according to X-ray diffraction (XRD) and the XRD results such as dislocation density, average grain size, and no. of crystallites per unit area. Atomic force microscopy was used to measure the film thickness and the surface properties. The critical surface tension of the PbSO3 thin films was measured with an optical tensiometer instrument and calculated using the Zisman method. The results indicated that the critical surface tension of films changed in accordance with the average grain size and film thickness. The film thickness increased with deposition time and was inversely correlated with surface tension. The average grain size increased according to deposition time and was inversely correlated with surface tension.

  18. Thin Films

    NASA Astrophysics Data System (ADS)

    Khorshidi, Zahra; Bahari, Ali; Gholipur, Reza

    2014-11-01

    Effect of annealing temperature on the characteristics of sol-gel-driven Ta ax La(1- a) x O y thin film spin-coated on Si substrate as a high- k gate dielectric was studied. Ta ax La(1- a) x O y thin films with different amounts of a were prepared (as-prepared samples). X-ray diffraction measurements of the as-prepared samples indicated that Ta0.3 x La0.7 x Oy film had an amorphous structure. Therefore, Ta0.3 x La0.7 x O y film was chosen to continue the present studies. The morphology of Ta0.3 x La0.7 x O y films was studied using scanning electron microscopy and atomic force microscopy techniques. The obtained results showed that the size of grain boundaries on Ta0.3 x La0.7 x O y film surfaces was increased with increasing annealing temperature. Electrical and optical characterizations of the as-prepared and annealed films were investigated as a function of annealing temperature using capacitance-voltage ( C- V) and current density-voltage ( J- V) measurements and the Tauc method. The obtained results demonstrated that Ta0.3 x La0.7 x O y films had high dielectric constant (≈27), wide band gap (≈4.5 eV), and low leakage current density (≈10-6 A/cm2 at 1 V).

  19. Thin Films

    NASA Astrophysics Data System (ADS)

    Naffouti, Wafa; Nasr, Tarek Ben; Mehdi, Ahmed; Kamoun-Turki, Najoua

    2014-11-01

    Titanium dioxide (TiO2) thin films were synthesized on glass substrates by spray pyrolysis. The effect of solution flow rate on the physical properties of the films was investigated by use of x-ray diffraction (XRD), scanning electron microscopy, atomic force microscopy (AFM), and spectrophotometry techniques. XRD analysis revealed the tetragonal anatase phase of TiO2 with highly preferred (101) orientation. AFM images showed that grain size on top of TiO2 thin films depended on solution flow rate. An indirect band gap energy of 3.46 eV was determined by means of transmission and reflection measurements. The envelope method, based on the optical transmission spectrum, was used to determine film thickness and optical constants, for example real and imaginary parts of the dielectric constant, refractive index, and extinction coefficient. Ultraviolet and visible photoluminescence emission peaks were observed at room temperature. These peaks were attributed to the intrinsic emission and to the surface defect states, respectively.

  20. Density-stratified flow events in Great Salt Lake, Utah, USA: implications for mercury and salinity cycling

    USGS Publications Warehouse

    Naftz, David L.; Carling, Gregory T.; Angeroth, Cory; Freeman, Michael; Rowland, Ryan; Pazmiño, Eddy

    2014-01-01

    Density stratification in saline and hypersaline water bodies from throughout the world can have large impacts on the internal cycling and loading of salinity, nutrients, and trace elements. High temporal resolution hydroacoustic and physical/chemical data were collected at two sites in Great Salt Lake (GSL), a saline lake in the western USA, to understand how density stratification may influence salinity and mercury (Hg) distributions. The first study site was in a causeway breach where saline water from GSL exchanges with less saline water from a flow restricted bay. Near-surface-specific conductance values measured in water at the breach displayed a good relationship with both flow and wind direction. No diurnal variations in the concentration of dissolved (total and MeHg loadings was observed during periods of elevated salinity. The second study site was located on the bottom of GSL where movement of a high-salinity water layer, referred to as the deep brine layer (DBL), is restricted to a naturally occurring 1.5-km-wide “spillway” structure. During selected time periods in April/May, 2012, wind-induced flow reversals in a railroad causeway breach, separating Gunnison and Gilbert Bays, were coupled with high-velocity flow pulses (up to 55 cm/s) in the DBL at the spillway site. These flow pulses were likely driven by a pressure response of highly saline water from Gunnison Bay flowing into the north basin of Gilbert Bay. Short-term flow reversal events measured at the railroad causeway breach have the ability to move measurable amounts of salt and Hg from Gunnison Bay into the DBL. Future disturbance to the steady state conditions currently imposed by the railroad causeway infrastructure could result in changes to the existing chemical balance between Gunnison and Gilbert Bays. Monitoring instruments were installed at six additional sites in the DBL during October 2012 to assess impacts from any future modifications to the railroad causeway.

  1. A semi-implicit spectral method for compressible convection of rotating and density-stratified flows in Cartesian geometry

    NASA Astrophysics Data System (ADS)

    Cai, Tao

    2016-04-01

    In this paper, we have described a 'stratified' semi-implicit spectral method to study compressible convection in Cartesian geometry. The full set of compressible hydrodynamic equations are solved in conservative forms. The numerical scheme is accurate and efficient, based on fast Fourier/sin/cos spectral transforms in the horizontal directions, Chebyshev spectral transform or second-order finite difference scheme in the vertical direction, and second order semi-implicit scheme in time marching of linear terms. We have checked the validity of both the fully pseudo-spectral scheme and the mixed finite-difference pseudo-spectral scheme by studying the onset of compressible convection. The difference of the critical Rayleigh number between our numerical result and the linear stability analysis is within two percent. Besides, we have computed the Mach numbers with different Rayleigh numbers in compressible convection. It shows good agreement with the numerical results of finite difference methods and finite volume method. This model has wide application in studying laminar and turbulent flow. Illustrative examples of application on horizontal convection, gravity waves, and long-lived vortex are given in this paper.

  2. Explosive magnetorotational instability in Keplerian disks

    NASA Astrophysics Data System (ADS)

    Shtemler, Yu.; Liverts, E.; Mond, M.

    2016-06-01

    Differentially rotating disks under the effect of axial magnetic field are prone to a nonlinear explosive magnetorotational instability (EMRI). The dynamic equations that govern the temporal evolution of the amplitudes of three weakly detuned resonantly interacting modes are derived. As distinct from exponential growth in the strict resonance triads, EMRI occurs due to the resonant interactions of an MRI mode with stable Alfvén-Coriolis and magnetosonic modes. Numerical solutions of the dynamic equations for amplitudes of a triad indicate that two types of perturbations behavior can be excited for resonance conditions: (i) EMRI which leads to infinite values of the three amplitudes within a finite time, and (ii) bounded irregular oscillations of all three amplitudes. Asymptotic explicit solutions of the dynamic equations are obtained for EMRI regimes and are shown to match the numerical solutions near the explosion time.

  3. Exact time-dependent solutions for the thin accretion disc equation: boundary conditions at finite radius

    NASA Astrophysics Data System (ADS)

    Tanaka, Takamitsu

    2011-01-01

    We discuss Green's function solutions of the equation for a geometrically thin, axisymmetric Keplerian accretion disc with a viscosity prescription ν∝Rn. The mathematical problem was solved by Lynden-Bell & Pringle for the special cases with boundary conditions of zero-viscous torque and zero mass flow at the disc centre. While it has been widely established that the observational appearance of astrophysical discs depends on the physical size of the central object(s), exact time-dependent solutions with boundary conditions imposed at finite radius have not been published for a general value of the power-law index n. We derive exact Green's function solutions that satisfy either a zero-torque or a zero-flux condition at a non-zero inner boundary Rin > 0, for an arbitrary initial surface density profile. Whereas the viscously dissipated power diverges at the disc centre for the previously known solutions with Rin= 0, the new solutions with Rin > 0 have finite expressions for the disc luminosity that agree, in the limit t→∞, with standard expressions for steady-state disc luminosities. The new solutions are applicable to the evolution of the innermost regions of thin accretion discs.

  4. Pyrolyzed thin film carbon

    NASA Technical Reports Server (NTRS)

    Tai, Yu-Chong (Inventor); Liger, Matthieu (Inventor); Harder, Theodore (Inventor); Konishi, Satoshi (Inventor); Miserendino, Scott (Inventor)

    2010-01-01

    A method of making carbon thin films comprises depositing a catalyst on a substrate, depositing a hydrocarbon in contact with the catalyst and pyrolyzing the hydrocarbon. A method of controlling a carbon thin film density comprises etching a cavity into a substrate, depositing a hydrocarbon into the cavity, and pyrolyzing the hydrocarbon while in the cavity to form a carbon thin film. Controlling a carbon thin film density is achieved by changing the volume of the cavity. Methods of making carbon containing patterned structures are also provided. Carbon thin films and carbon containing patterned structures can be used in NEMS, MEMS, liquid chromatography, and sensor devices.

  5. Thin film hydrogen sensor

    DOEpatents

    Cheng, Y.T.; Poli, A.A.; Meltser, M.A.

    1999-03-23

    A thin film hydrogen sensor includes a substantially flat ceramic substrate with first and second planar sides and a first substrate end opposite a second substrate end; a thin film temperature responsive resistor on the first planar side of the substrate proximate to the first substrate end; a thin film hydrogen responsive metal resistor on the first planar side of the substrate proximate to the fist substrate end and proximate to the temperature responsive resistor; and a heater on the second planar side of the substrate proximate to the first end. 5 figs.

  6. Electrochemical thinning of silicon

    SciTech Connect

    Medernach, J.W.

    1994-01-11

    Porous semiconducting material, e.g. silicon, is formed by electrochemical treatment of a specimen in hydrofluoric acid, using the specimen as anode. Before the treatment, the specimen can be masked. The porous material is then etched with a caustic solution or is oxidized, depending of the kind of structure desired, e.g. a thinned specimen, a specimen, a patterned thinned specimen, a specimen with insulated electrical conduits, and so on. Thinned silicon specimen can be subjected to tests, such as measurement of interstitial oxygen by Fourier transform infra-red spectroscopy (FTIR). 14 figures.

  7. Electrochemical thinning of silicon

    DOEpatents

    Medernach, John W.

    1994-01-01

    Porous semiconducting material, e.g. silicon, is formed by electrochemical treatment of a specimen in hydrofluoric acid, using the specimen as anode. Before the treatment, the specimen can be masked. The porous material is then etched with a caustic solution or is oxidized, depending of the kind of structure desired, e.g. a thinned specimen, a specimen, a patterned thinned specimen, a specimen with insulated electrical conduits, and so on. Thinned silicon specimen can be subjected to tests, such as measurement of interstitial oxygen by Fourier transform infra-red spectroscopy (FTIR).

  8. Biomimetic thin film synthesis

    SciTech Connect

    Graff, G.L.; Campbell, A.A.; Gordon, N.R.

    1995-05-01

    The purpose of this program is to develop a new process for forming thin film coatings and to demonstrate that the biomimetic thin film technology developed at PNL is useful for industrial applications. In the biomimetic process, mineral deposition from aqueous solution is controlled by organic functional groups attached to the underlying substrate surface. The coatings process is simple, benign, inexpensive, energy efficient, and particularly suited for temperature sensitive substrate materials (such as polymers). In addition, biomimetic thin films can be deposited uniformly on complex shaped and porous substrates providing a unique capability over more traditional line-of-sight methods.

  9. Thin film hydrogen sensor

    DOEpatents

    Cheng, Yang-Tse; Poli, Andrea A.; Meltser, Mark Alexander

    1999-01-01

    A thin film hydrogen sensor, includes: a substantially flat ceramic substrate with first and second planar sides and a first substrate end opposite a second substrate end; a thin film temperature responsive resistor on the first planar side of the substrate proximate to the first substrate end; a thin film hydrogen responsive metal resistor on the first planar side of the substrate proximate to the fist substrate end and proximate to the temperature responsive resistor; and a heater on the second planar side of the substrate proximate to the first end.

  10. Thin-disk models in an integrable Weyl-Dirac theory

    NASA Astrophysics Data System (ADS)

    Vieira, Ronaldo S. S.; Letelier, Patricio S.

    2014-01-01

    We construct a class of static, axially symmetric solutions representing razor-thin disks of matter in the Integrable Weyl-Dirac theory proposed in Israelit (Found Phys 29:1303, 1999). The main differences between these solutions and the corresponding general relativistic one are analyzed, focusing on the behavior of physical observables (rotation curves of test particles, density and pressure profiles). We consider the case in which test particles move along Weyl geodesics. The same rotation curve can be obtained from many different solutions of the Weyl-Dirac theory, although some of these solutions present strong qualitative differences with respect to the usual general relativistic model (such as the appearance of a ring-like density profile). In particular, for typical galactic parameters all rotation curves of the Weyl-Dirac model present Keplerian fall-off. As a consequence, we conclude that a more thorough analysis of the problem requires the determination of the gauge function on galactic scales, as well as restrictions on the test-particle behavior under the action of the additional geometrical fields introduced by this theory.

  11. Ceramic Composite Thin Films

    NASA Technical Reports Server (NTRS)

    Ruoff, Rodney S. (Inventor); Stankovich, Sasha (Inventor); Dikin, Dmitriy A. (Inventor); Nguyen, SonBinh T. (Inventor)

    2013-01-01

    A ceramic composite thin film or layer includes individual graphene oxide and/or electrically conductive graphene sheets dispersed in a ceramic (e.g. silica) matrix. The thin film or layer can be electrically conductive film or layer depending the amount of graphene sheets present. The composite films or layers are transparent, chemically inert and compatible with both glass and hydrophilic SiOx/silicon substrates. The composite film or layer can be produced by making a suspension of graphene oxide sheet fragments, introducing a silica-precursor or silica to the suspension to form a sol, depositing the sol on a substrate as thin film or layer, at least partially reducing the graphene oxide sheets to conductive graphene sheets, and thermally consolidating the thin film or layer to form a silica matrix in which the graphene oxide and/or graphene sheets are dispersed.

  12. Super Thin Ceramic Coatings

    NASA Video Gallery

    New technology being developed at NASA's Glenn Research Center creates super thin ceramic coatings on engine components. The Plasma Spray – Physical Vapor Deposition (PS-PVD) rig uses a powerful ...

  13. Thin film metrology.

    PubMed

    Nitsch, Gerald; Flinn, Gregory

    2007-10-01

    Thin film metrology is suitable for characterising and performing quality control of a variety of coatings and films used in medical applications. The capabilities of today's systems are described. PMID:18078184

  14. Line Thinning Algorithm

    NASA Astrophysics Data System (ADS)

    Feigin, G.; Ben-Yosef, N.

    1983-10-01

    A thinning algorithm, of the banana-peel type, is presented. In each iteration pixels are attacked from all directions (there are no sub-iterations), and the deletion criteria depend on the 24 nearest neighbours.

  15. Multifunctional thin film surface

    SciTech Connect

    Brozik, Susan M.; Harper, Jason C.; Polsky, Ronen; Wheeler, David R.; Arango, Dulce C.; Dirk, Shawn M.

    2015-10-13

    A thin film with multiple binding functionality can be prepared on an electrode surface via consecutive electroreduction of two or more aryl-onium salts with different functional groups. This versatile and simple method for forming multifunctional surfaces provides an effective means for immobilization of diverse molecules at close proximities. The multifunctional thin film has applications in bioelectronics, molecular electronics, clinical diagnostics, and chemical and biological sensing.

  16. Thin silicon solar cells

    SciTech Connect

    Hall, R.B.; Bacon, C.; DiReda, V.; Ford, D.H.; Ingram, A.E.; Cotter, J.; Hughes-Lampros, T.; Rand, J.A.; Ruffins, T.R.; Barnett, A.M.

    1992-12-01

    The silicon-film design achieves high performance by using a dun silicon layer and incorporating light trapping. Optimally designed thin crystalline solar cells (<50 microns thick) have performance advantages over conventional thick devices. The high-performance silicon-film design employs a metallurgical barrier between the low-cost substrate and the thin silicon layer. Light trapping properties of silicon-film on ceramic solar cells are presented and analyzed. Recent advances in process development are described here.

  17. Thin film tritium dosimetry

    DOEpatents

    Moran, Paul R.

    1976-01-01

    The present invention provides a method for tritium dosimetry. A dosimeter comprising a thin film of a material having relatively sensitive RITAC-RITAP dosimetry properties is exposed to radiation from tritium, and after the dosimeter has been removed from the source of the radiation, the low energy electron dose deposited in the thin film is determined by radiation-induced, thermally-activated polarization dosimetry techniques.

  18. Lithospheric and crustal thinning

    NASA Technical Reports Server (NTRS)

    Moretti, I.

    1985-01-01

    In rift zones, both the crust and the lithosphere get thinner. The amplitude and the mechanism of these two thinning situations are different. The lithospheric thinning is a thermal phenomenon produced by an asthenospherical uprising under the rift zone. In some regions its amplitude can exceed 200%. This is observed under the Baikal rift where the crust is directly underlaid by the mantellic asthenosphere. The presence of hot material under rift zones induces a large negative gravity anomaly. A low seismic velocity zone linked to this thermal anomaly is also observed. During the rifting, the magmatic chambers get progressively closer from the ground surface. Simultaneously, the Moho reflector is found at shallow depth under rift zones. This crustal thinning does not exceed 50%. Tectonic stresses and vertical movements result from the two competing effects of the lithospheric and crustal thinning. On the one hand, the deep thermal anomaly induces a large doming and is associated with extensive deviatoric stresses. On the other hand, the crustal thinning involves the formation of a central valley. This subsidence is increased by the sediment loading. The purpose here is to quantify these two phenomena in order to explain the morphological and thermal evolution of rift zones.

  19. Thin film temperature sensor

    NASA Technical Reports Server (NTRS)

    Grant, H. P.; Przybyszewski, J. S.

    1980-01-01

    Thin film surface temperature sensors were developed. The sensors were made of platinum-platinum/10 percent rhodium thermocouples with associated thin film-to-lead wire connections and sputtered on aluminum oxide coated simulated turbine blades for testing. Tests included exposure to vibration, low velocity hydrocarbon hot gas flow to 1250 K, and furnace calibrations. Thermal electromotive force was typically two percent below standard type S thermocouples. Mean time to failure was 42 hours at a hot gas flow temperature of 1250 K and an average of 15 cycles to room temperature. Failures were mainly due to separation of the platinum thin film from the aluminum oxide surface. Several techniques to improve the adhesion of the platinum are discussed.

  20. Thin film photovoltaics

    SciTech Connect

    Zweibel, K; Ullal, H S

    1989-05-01

    Thin films are considered a potentially attractive technological approach to making cost-effective electricity by photovoltaics. Over the last twenty years, many have been investigated and some (cadmium telluride, copper indium diselenide, amorphous silicon) have become leading candidates for future large-scale commercialization. This paper surveys the past development of these key thin films and gives their status and future prospects. In all cases, significant progress toward cost-effective PV electricity has been made. If this progress continues, it appears that thin film PV could provide electricity that is competitive for summer daytime peaking power requirements by the middle of the 1990s; and electricity in a range that is competitive with fossil fuel costs (i.e., 6 cents/kilowatt-hour) should be available from PV around the turn of the century. 22 refs., 9 figs.

  1. Thin-film optical initiator

    DOEpatents

    Erickson, Kenneth L.

    2001-01-01

    A thin-film optical initiator having an inert, transparent substrate, a reactive thin film, which can be either an explosive or a pyrotechnic, and a reflective thin film. The resultant thin-film optical initiator system also comprises a fiber-optic cable connected to a low-energy laser source, an output charge, and an initiator housing. The reactive thin film, which may contain very thin embedded layers or be a co-deposit of a light-absorbing material such as carbon, absorbs the incident laser light, is volumetrically heated, and explodes against the output charge, imparting about 5 to 20 times more energy than in the incident laser pulse.

  2. Thin film ceramic thermocouples

    NASA Technical Reports Server (NTRS)

    Gregory, Otto (Inventor); Fralick, Gustave (Inventor); Wrbanek, John (Inventor); You, Tao (Inventor)

    2011-01-01

    A thin film ceramic thermocouple (10) having two ceramic thermocouple (12, 14) that are in contact with each other in at least on point to form a junction, and wherein each element was prepared in a different oxygen/nitrogen/argon plasma. Since each element is prepared under different plasma conditions, they have different electrical conductivity and different charge carrier concentration. The thin film thermocouple (10) can be transparent. A versatile ceramic sensor system having an RTD heat flux sensor can be combined with a thermocouple and a strain sensor to yield a multifunctional ceramic sensor array. The transparent ceramic temperature sensor that could ultimately be used for calibration of optical sensors.

  3. Thin film photovoltaic device

    DOEpatents

    Catalano, Anthony W.; Bhushan, Manjul

    1982-01-01

    A thin film photovoltaic solar cell which utilizes a zinc phosphide semiconductor is of the homojunction type comprising an n-type conductivity region forming an electrical junction with a p-type region, both regions consisting essentially of the same semiconductor material. The n-type region is formed by treating zinc phosphide with an extrinsic dopant such as magnesium. The semiconductor is formed on a multilayer substrate which acts as an opaque contact. Various transparent contacts may be used, including a thin metal film of the same chemical composition as the n-type dopant or conductive oxides or metal grids.

  4. Thin film photovoltaic device

    DOEpatents

    Catalano, A.W.; Bhushan, M.

    1982-08-03

    A thin film photovoltaic solar cell which utilizes a zinc phosphide semiconductor is of the homojunction type comprising an n-type conductivity region forming an electrical junction with a p-type region, both regions consisting essentially of the same semiconductor material. The n-type region is formed by treating zinc phosphide with an extrinsic dopant such as magnesium. The semiconductor is formed on a multilayer substrate which acts as an opaque contact. Various transparent contacts may be used, including a thin metal film of the same chemical composition as the n-type dopant or conductive oxides or metal grids. 5 figs.

  5. Shear Thinning in Xenon

    NASA Technical Reports Server (NTRS)

    Bergm Robert F.; Moldover, Michael R.; Yao, Minwu; Zimmerli, Gregory A.

    2009-01-01

    We measured shear thinning, a viscosity decrease ordinarily associated with complex liquids such as molten plastics or ketchup, near the critical point of xenon. The data span a wide range of dimensionless shear rate: the product of the shear rate and the relaxation time of critical fluctuations was greater than 0.001 and was less than 700. As predicted by theory, shear thinning occurred when this product was greater than 1. The measurements were conducted aboard the Space Shuttle Columbia to avoid the density stratification caused by Earth's gravity.

  6. Treading on Thin Water.

    ERIC Educational Resources Information Center

    Haley, Richard D.

    1985-01-01

    Provides a simple introduction to animals whose habitat is the thin surface film of water. Describes adaptive mechanisms of water striders, whirlygigs and riffle bugs and suggests ways to observe them in the wild or as aquarium animals. Includes basic demonstrations of the nature of surface tension. (JHZ)

  7. Thin Lens Ray Tracing.

    ERIC Educational Resources Information Center

    Gatland, Ian R.

    2002-01-01

    Proposes a ray tracing approach to thin lens analysis based on a vector form of Snell's law for paraxial rays as an alternative to the usual approach in introductory physics courses. The ray tracing approach accommodates skew rays and thus provides a complete analysis. (Author/KHR)

  8. Thin Wall Iron Castings

    SciTech Connect

    J.F. Cuttino; D.M. Stefanescu; T.S. Piwonka

    2001-10-31

    Results of an investigation made to develop methods of making iron castings having wall thicknesses as small as 2.5 mm in green sand molds are presented. It was found that thin wall ductile and compacted graphite iron castings can be made and have properties consistent with heavier castings. Green sand molding variables that affect casting dimensions were also identified.

  9. Thin film photovoltaic cell

    DOEpatents

    Meakin, John D.; Bragagnolo, Julio

    1982-01-01

    A thin film photovoltaic cell having a transparent electrical contact and an opaque electrical contact with a pair of semiconductors therebetween includes utilizing one of the electrical contacts as a substrate and wherein the inner surface thereof is modified by microroughening while being macro-planar.

  10. Epitaxial thin films

    DOEpatents

    Hunt, Andrew Tye; Deshpande, Girish; Lin, Wen-Yi; Jan, Tzyy-Jiuan

    2006-04-25

    Epitatial thin films for use as buffer layers for high temperature superconductors, electrolytes in solid oxide fuel cells (SOFC), gas separation membranes or dielectric material in electronic devices, are disclosed. By using CCVD, CACVD or any other suitable deposition process, epitaxial films having pore-free, ideal grain boundaries, and dense structure can be formed. Several different types of materials are disclosed for use as buffer layers in high temperature superconductors. In addition, the use of epitaxial thin films for electrolytes and electrode formation in SOFCs results in densification for pore-free and ideal gain boundary/interface microstructure. Gas separation membranes for the production of oxygen and hydrogen are also disclosed. These semipermeable membranes are formed by high-quality, dense, gas-tight, pinhole free sub-micro scale layers of mixed-conducting oxides on porous ceramic substrates. Epitaxial thin films as dielectric material in capacitors are also taught herein. Capacitors are utilized according to their capacitance values which are dependent on their physical structure and dielectric permittivity. The epitaxial thin films of the current invention form low-loss dielectric layers with extremely high permittivity. This high permittivity allows for the formation of capacitors that can have their capacitance adjusted by applying a DC bias between their electrodes.

  11. Thin films for material engineering

    NASA Astrophysics Data System (ADS)

    Wasa, Kiyotaka

    2016-07-01

    Thin films are defined as two-dimensional materials formed by condensing one by one atomic/molecular/ionic species of matter in contrast to bulk three-dimensional sintered ceramics. They are grown through atomic collisional chemical reaction on a substrate surface. Thin film growth processes are fascinating for developing innovative exotic materials. On the basis of my long research on sputtering deposition, this paper firstly describes the kinetic energy effect of sputtered adatoms on thin film growth and discusses on a possibility of room-temperature growth of cubic diamond crystallites and the perovskite thin films of binary compound PbTiO3. Secondly, high-performance sputtered ferroelectric thin films with extraordinary excellent crystallinity compatible with MBE deposited thin films are described in relation to a possible application for thin-film MEMS. Finally, the present thin-film technologies are discussed in terms of a future material science and engineering.

  12. Thin film solar cell workshop

    NASA Technical Reports Server (NTRS)

    Armstrong, Joe; Jeffrey, Frank

    1993-01-01

    A summation of responses to questions posed to the thin-film solar cell workshop and the ensuing discussion is provided. Participants in the workshop included photovoltaic manufacturers (both thin film and crystalline), cell performance investigators, and consumers.

  13. NMR characterization of thin films

    DOEpatents

    Gerald II, Rex E.; Klingler, Robert J.; Rathke, Jerome W.; Diaz, Rocio; Vukovic, Lela

    2010-06-15

    A method, apparatus, and system for characterizing thin film materials. The method, apparatus, and system includes a container for receiving a starting material, applying a gravitational force, a magnetic force, and an electric force or combinations thereof to at least the starting material, forming a thin film material, sensing an NMR signal from the thin film material and analyzing the NMR signal to characterize the thin film of material.

  14. NMR characterization of thin films

    DOEpatents

    Gerald, II, Rex E.; Klingler, Robert J.; Rathke, Jerome W.; Diaz, Rocio; Vukovic, Lela

    2008-11-25

    A method, apparatus, and system for characterizing thin film materials. The method, apparatus, and system includes a container for receiving a starting material, applying a gravitational force, a magnetic force, and an electric force or combinations thereof to at least the starting material, forming a thin film material, sensing an NMR signal from the thin film material and analyzing the NMR signal to characterize the thin film of material.

  15. Shear-thinning Fluid

    NASA Technical Reports Server (NTRS)

    2001-01-01

    Whipped cream and the filling for pumpkin pie are two familiar materials that exhibit the shear-thinning effect seen in a range of industrial applications. It is thick enough to stand on its own atop a piece of pie, yet flows readily when pushed through a tube. This demonstrates the shear-thinning effect that was studied with the Critical Viscosity of Xenon Experiment (CVX-2) on the STS-107 Research 1 mission in 2002. CVX observed the behavior of xenon, a heavy inert gas used in flash lamps and ion rocket engines, at its critical point. The principal investigator was Dr. Robert Berg of the National Institutes of Standards and Technology in Gaithersburg, MD.

  16. Advanced thin film thermocouples

    NASA Astrophysics Data System (ADS)

    Kreider, K. G.; Semancik, S.; Olson, C.

    1984-10-01

    The fabrication, materials characterization, and performance of thin film platinum rhodium thermocouples on gas turbine alloys was investigated. The materials chosen for the study were the turbine blade alloy systems MAR M200+Hf with NiCoCrAlY and FeCrAlY coatings, and vane alloy systems MAR M509 with FeCrAlY. Research was focussed on making improvements in the problem areas of coating substrate stability, adhesion, and insulation reliability and durability. Diffusion profiles between the substrate and coating with and without barrier coatings of Al2O3 are reported. The relationships between fabrication parameters of thermal oxidation and sputtering of the insulator and its characterization and performance are described. The best thin film thermocouples were fabricated with the NiCoCrAlY coatings which were thermally oxidized and sputter coated with Al2O3.

  17. Biomimetic thin film deposition

    SciTech Connect

    Rieke, P.R.; Graff, G.E.; Campbell, A.A.; Bunker, B.C.; Baskaran, S.; Song, L.; Tarasevich, B.J.; Fryxell, G.E.

    1995-09-01

    Biological mineral deposition for the formation of bone, mollusk shell and other hard tissues provides materials scientists with illustrative materials processing strategies. This presentation will review the key features of biomineralization and how these features can be of technical importance. We have adapted existing knowledge of biomineralization to develop a unique method of depositing inorganic thin films and coating. Our approach to thin film deposition is to modify substrate surfaces to imitate the proteins found in nature that are responsible for controlling mineral deposition. These biomimetic surfaces control the nucleation and growth of the mineral from a supersaturated aqueous solution. This has many processing advantages including simple processing equipment, environmentally benign reagents, uniform coating of highly complex shapes, and enhanced adherence of coating. Many different types of metal oxide, hydroxide, sulfide and phosphate materials with useful mechanical, optical, electronic and biomedical properties can be deposited.

  18. Advanced thin film thermocouples

    NASA Technical Reports Server (NTRS)

    Kreider, K. G.; Semancik, S.; Olson, C.

    1984-01-01

    The fabrication, materials characterization, and performance of thin film platinum rhodium thermocouples on gas turbine alloys was investigated. The materials chosen for the study were the turbine blade alloy systems MAR M200+Hf with NiCoCrAlY and FeCrAlY coatings, and vane alloy systems MAR M509 with FeCrAlY. Research was focussed on making improvements in the problem areas of coating substrate stability, adhesion, and insulation reliability and durability. Diffusion profiles between the substrate and coating with and without barrier coatings of Al2O3 are reported. The relationships between fabrication parameters of thermal oxidation and sputtering of the insulator and its characterization and performance are described. The best thin film thermocouples were fabricated with the NiCoCrAlY coatings which were thermally oxidized and sputter coated with Al2O3.

  19. Ultra-Thin, Flexible Electronics

    NASA Technical Reports Server (NTRS)

    Holland, Brian; McPherson, Ryan; Zhang, Tan; Hou, Zhenwei; Dean, Robert; Johnson, R. Wayne; DelCastillo, Linda; Moussessian, Alina

    2008-01-01

    Thinned die can be used to realize ultra-thin flexible electronics for applications such as conformal and wearable electronics. Three techniques have been developed to achieve this goal using thinned die: die flip chip bonded onto flexible substrates, die laminated onto LCP films, and die embedded in polyimide. A key to achieving each of these techniques is the thinning of die to a thickness of 50 microns or thinner. Conventional CMP processing can be used to thin to 50 microns. At 50 microns, the active die become flexible and must be handled by temporarily bonding them to a holder die, for further processing. Once bonded face down to the holder die, the active die can be further thinned by DRIE etching the exposed backside. The thinned die can then been packaged in or on the flexible substrate.

  20. Thin film superconductor magnetic bearings

    DOEpatents

    Weinberger, Bernard R.

    1995-12-26

    A superconductor magnetic bearing includes a shaft (10) that is subject to a load (L) and rotatable around an axis of rotation, a magnet (12) mounted to the shaft, and a stator (14) in proximity to the shaft. The stator (14) has a superconductor thin film assembly (16) positioned to interact with the magnet (12) to produce a levitation force on the shaft (10) that supports the load (L). The thin film assembly (16) includes at least two superconductor thin films (18) and at least one substrate (20). Each thin film (18) is positioned on a substrate (20) and all the thin films are positioned such that an applied magnetic field from the magnet (12) passes through all the thin films. A similar bearing in which the thin film assembly (16) is mounted on the shaft (10) and the magnet (12) is part of the stator (14) also can be constructed.

  1. Thin film superconductor magnetic bearings

    SciTech Connect

    Weinberger, B.R.

    1995-12-26

    A superconductor magnetic bearing includes a shaft that is subject to a load (L) and rotatable around an axis of rotation, a magnet mounted to the shaft, and a stator in proximity to the shaft. The stator has a superconductor thin film assembly positioned to interact with the magnet to produce a levitation force on the shaft that supports the load (L). The thin film assembly includes at least two superconductor thin films and at least one substrate. Each thin film is positioned on a substrate and all the thin films are positioned such that an applied magnetic field from the magnet passes through all the thin films. A similar bearing in which the thin film assembly is mounted on the shaft and the magnet is part of the stator also can be constructed. 8 figs.

  2. Evaporated VOx Thin Films

    NASA Astrophysics Data System (ADS)

    Stapinski, Tomasz; Leja, E.

    1989-03-01

    VOx thin films on glass were obtained by thermal evaporation of V205, powder. The structural investigations were carried out with the use of X-ray diffractometer. The electrical properties of the film were examined by means of temperature measurements of resistivity for the samples heat-treated in various conditions. Optical transmission and reflection spectra of VOX films of various composition showed the influence of the heat treatment.

  3. Thin, Lightweight Solar Cell

    NASA Technical Reports Server (NTRS)

    Brandhorst, Henry W., Jr.; Weinberg, Irving

    1991-01-01

    Improved design for thin, lightweight solar photovoltaic cells with front contacts reduces degradation of electrical output under exposure to energetic charged particles (protons and electrons). Increases ability of cells to maintain structural integrity under exposure to ultraviolet radiation by eliminating ultraviolet-degradable adhesives used to retain cover glasses. Interdigitated front contacts and front junctions formed on semiconductor substrate. Mating contacts formed on back surface of cover glass. Cover glass and substrate electrostatically bonded together.

  4. Polycrystalline thin film photovoltaics

    NASA Astrophysics Data System (ADS)

    Zweibel, K.; Ullal, H. S.; Mitchell, R. L.

    Significant progress has recently been made towards improving the efficiencies of polycrystalline thin-film solar cells and modules using CuInSe2 and CdTe. The history of using CuInSe2 and CdTe for solar cells is reviewed. Initial outdoor stability tests of modules are encouraging. Progress in semiconductor deposition techniques has also been substantial. Both CuInSe2 and CdTe are positioned for commercialization during the 1990s. The major participants in developing these materials are described. The US DOE/SERI (Solar Energy Research Institute) program recognizes the rapid progress and important potential of polycrystalline thin films to meet ambitious cost and performance goals. US DOE/SERI is in the process of funding an initiative in this area with the goal of ensuring US leadership in the development of these technologies. The polycrystalline thin-film module development initiative, the modeling and stability of the devices, and health and safety issues are discussed.

  5. Thin film scintillators

    NASA Astrophysics Data System (ADS)

    McDonald, Warren; McKinney, George; Tzolov, Marian

    2015-03-01

    Scintillating materials convert energy flux (particles or electromagnetic waves) into light with spectral characteristic matching a subsequent light detector. Commercial scintillators such as yttrium aluminum garnet (YAG) and yttrium aluminum perovskite (YAP) are commonly used. These are inefficient at lower energies due to the conductive coating present on their top surface, which is needed to avoid charging. We hypothesize that nano-structured thin film scintillators will outperform the commercial scintillators at low electron energies. We have developed alternative thin film scintillators, zinc tungstate and zinc oxide, which show promise for higher sensitivity to lower energy electrons since they are inherently conductive. Zinc tungstate films exhibit photoluminescence quantum efficiency of 74%. Cathodoluminescence spectroscopy was applied in transmission and reflection geometries. The comparison between the thin films and the YAG and YAP commercial scintillators shows much higher light output from the zinc tungstate and zinc oxide at electron energies less than 5 keV. Our films were integrated in a backscattered electron detector. This detector delivers better images than an identical detector with commercial YAG scintillator at low electron energies. Dr. Nicholas Barbi from PulseTor LLC, Dr. Anura Goonewardene, NSF Grants: #0806660, #1058829, #0923047.

  6. thin films as absorber

    NASA Astrophysics Data System (ADS)

    González, J. O.; Shaji, S.; Avellaneda, D.; Castillo, G. A.; Das Roy, T. K.; Krishnan, B.

    2014-09-01

    Photovoltaic structures were prepared using AgSb(S x Se1- x )2 as absorber and CdS as window layer at various conditions via a hybrid technique of chemical bath deposition and thermal evaporation followed by heat treatments. Silver antimony sulfo selenide thin films [AgSb(S x Se1- x )2] were prepared by heating multilayers of sequentially deposited Sb2S3/Ag dipped in Na2SeSO3 solution, glass/Sb2S3/Ag/Se. For this, Sb2S3 thin films were deposited from a chemical bath containing SbCl3 and Na2S2O3. Then, Ag thin films were thermally evaporated on glass/Sb2S3, followed by selenization by dipping in an acidic solution of Na2SeSO3. The duration of dipping was varied as 3, 4 and 5 h. Two different heat treatments, one at 350 °C for 20 min in vacuum followed by a post-heat treatment at 325 °C for 2 h in Ar, and the other at 350 °C for 1 h in Ar, were applied to the multilayers of different configurations. X-ray diffraction results showed the formation of AgSb(S x Se1- x )2 thin films as the primary phase and AgSb(S,Se)2 and Sb2S3 as secondary phases. Morphology and elemental detection were done by scanning electron microscopy and energy dispersive X-ray analysis. X-ray photoelectron spectroscopic studies showed the depthwise composition of the films. Optical properties were determined by UV-vis-IR transmittance and reflection spectral analysis. AgSb(S x Se1- x )2 formed at different conditions was incorporated in PV structures glass/FTO/CdS/AgSb(S x Se1- x )2/C/Ag. Chemically deposited post-annealed CdS thin films of various thicknesses were used as window layer. J- V characteristics of the cells were measured under dark and AM1.5 illumination. Analysis of the J- V characteristics resulted in the best solar cell parameters of V oc = 520 mV, J sc = 9.70 mA cm-2, FF = 0.50 and η = 2.7 %.

  7. On the theory of thin and thin-walled rods

    NASA Technical Reports Server (NTRS)

    Dzhanelidze, G Y

    1951-01-01

    Through the work of V. Z. Vlasov a theory of thin-walled rods has been established that is widely applicable in practice. This theory was extended by A. A. Umanski to thin-walled rods of closed profile section. The authors based their work on the concepts of the modern theory of shells. An attempt is made herein to construct a theory of thin-walled rods including the classical theory of deformation of thin rods by making use of a kinematic assumption.

  8. Carbon thin film thermometry

    NASA Technical Reports Server (NTRS)

    Collier, R. S.; Sparks, L. L.; Strobridge, T. R.

    1973-01-01

    The work concerning carbon thin film thermometry is reported. Optimum film deposition parameters were sought on an empirical basis for maximum stability of the films. One hundred films were fabricated for use at the Marshall Space Flight Center; 10 of these films were given a precise quasi-continuous calibration of temperature vs. resistance with 22 intervals between 5 and 80 K using primary platinum and germanium thermometers. Sensitivity curves were established and the remaining 90 films were given a three point calibration and fitted to the established sensitivity curves. Hydrogen gas-liquid discrimination set points are given for each film.

  9. Method for thinning specimen

    DOEpatents

    Follstaedt, David M.; Moran, Michael P.

    2005-03-15

    A method for thinning (such as in grinding and polishing) a material surface using an instrument means for moving an article with a discontinuous surface with an abrasive material dispersed between the material surface and the discontinuous surface where the discontinuous surface of the moving article provides an efficient means for maintaining contact of the abrasive with the material surface. When used to dimple specimens for microscopy analysis, a wheel with a surface that has been modified to produce a uniform or random discontinuous surface significantly improves the speed of the dimpling process without loss of quality of finish.

  10. Ureilite Thin Section Preparation

    NASA Technical Reports Server (NTRS)

    Harrington, R.; Righter, K.

    2014-01-01

    Preparing thin and thick sections of ureilite type meteorites is a challenge that can confound even the most experienced section preparer. A common characteristic of these samples is the presence of carbon phases, particularly nanodiamonds, in the matrix along silicate grain boundaries, fractures, and cleavage plains [1]. The extreme hardness of the nanodiamonds presents a challenge to the section preparer in the form of high surface relief on the section. This hard material also causes considerable wear and tear on equipment and materials that are used for making the sections. These issues will be discussed and potentially helpful measures will be presented.

  11. Polycrystalline thin-films

    NASA Astrophysics Data System (ADS)

    Zweibel, K.; Mitchell, R.

    1986-02-01

    This annual report summarizes the status, accomplishments, and projected future research directions of the Polycrystalline Thin Film Task in the Photovoltaic Program Branch of the Solar Energy Research Institute's Solar Electric Research Division. Major subcontracted work in this area has concentrated on development of CuInSe2 and CdTe technologies. During FY 1985, major progress was achieved by subcontractors in: (1) developing a new, low-cost method of fabricating CuInSe2, and (2) improving the efficiency of CuInSe2 devices by about 10% (relative). The report also lists research planned to meet the Department of Energy's goals in these technologies.

  12. Thin film hydrogen sensor

    DOEpatents

    Lauf, Robert J.; Hoffheins, Barbara S.; Fleming, Pamela H.

    1994-01-01

    A hydrogen sensor element comprises an essentially inert, electrically-insulating substrate having a thin-film metallization deposited thereon which forms at least two resistors on the substrate. The metallization comprises a layer of Pd or a Pd alloy for sensing hydrogen and an underlying intermediate metal layer for providing enhanced adhesion of the metallization to the substrate. An essentially inert, electrically insulating, hydrogen impermeable passivation layer covers at least one of the resistors, and at least one of the resistors is left uncovered. The difference in electrical resistances of the covered resistor and the uncovered resistor is related to hydrogen concentration in a gas to which the sensor element is exposed.

  13. Polycrystalline thin film photovoltaic technology

    SciTech Connect

    Ullal, H.S.; Zweibel, K.; Mitchell, R.L.; Noufi, R.

    1991-03-01

    Low-cost, high-efficiency thin-film modules are an exciting photovoltaic technology option for generating cost-effective electricity in 1995 and beyond. In this paper we review the significant technical progress made in the following thin films: copper indium diselenide, cadmium telluride, and polycrystalline thin silicon films. Also, the recent US DOE/SERI initiative to commercialize these emerging technologies is discussed. 6 refs., 9 figs.

  14. Thin-Film Power Transformers

    NASA Technical Reports Server (NTRS)

    Katti, Romney R.

    1995-01-01

    Transformer core made of thin layers of insulating material interspersed with thin layers of ferromagnetic material. Flux-linking conductors made of thinner nonferromagnetic-conductor/insulator multilayers wrapped around core. Transformers have geometric features finer than those of transformers made in customary way by machining and mechanical pressing. In addition, some thin-film materials exhibit magnetic-flux-carrying capabilities superior to those of customary bulk transformer materials. Suitable for low-cost, high-yield mass production.

  15. Center for thin film studies

    NASA Astrophysics Data System (ADS)

    Shannon, Robert P.; Gibson, Ursula J.

    1987-11-01

    This report covers the first year of operation of the URI Thin Film Center (TFC), and describes a diverse array of studies on thin-film materials, substrates, and their processing and analysis. Individual efforts are highlighted in sections on nucleation studies, ion-assisted deposition, Rutherford backscattering spectrometry, Brillouin scattering, a continuum theory of the evolution of structure in thin films, a study of polishing parameters relevant to the preparation of substrates, and the setup of a characterization facility for the Center.

  16. Thin-film microextraction.

    PubMed

    Bruheim, Inge; Liu, Xiaochuan; Pawliszyn, Janusz

    2003-02-15

    The properties of a thin sheet of poly(dimethylsiloxane) (PDMS) membrane as an extraction phase were examined and compared to solid-phase microextraction (SPME) PDMS-coated fiber for application to semivolatile analytes in direct and headspace modes. This new PDMS extraction approach showed much higher extraction rates because of the larger surface area to extraction-phase volume ratio of the thin film. Unlike the coated rod formats of SPME using thick coatings, the high extraction rate of the membrane SPME technique allows larger amounts of analytes to be extracted within a short period of time. Therefore, higher extraction efficiency and sensitivity can be achieved without sacrificing analysis time. In direct membrane SPME extraction, a linear relationship was found between the initial rate of extraction and the surface area of the extraction phase. However, for headspace extraction, the rates were somewhat lower because of the resistance to analyte transport at the sample matrix/headspace barrier. It was found that the effect of this barrier could be reduced by increasing either agitation, temperature, or surface area of the sample matrix/headspace interface. A method for the determination of PAHs in spiked lake water samples was developed based on the membrane PDMS extraction coupled with GC/MS. A linearity of 0.9960 and detection limits in the low-ppt level were found. The reproducibility was found to vary from 2.8% to 10.7%. PMID:12622398

  17. The thin eggshell problem

    USGS Publications Warehouse

    Stickel, L.F.; Rhodes, L.I.

    1970-01-01

    It has long been known that DDT and related chemicals can impair the reproduction of birds. In early years of organochlorine pesticide use, widespread mortality occurred immediately following heavy applications of these chemicals, and survivors contained substantial amounts of toxicant in their tissues. Repopulation from untreated areas tended to conceal the extent of the effects. DDT and dieldrin have become ubiquitous and the original source of the chemicals producing bird deaths often cannot be traced. The extent of sublethal effects cannot be fully appraised, although laboratory experiments continually reveal new and potentially deleterious physiological reactions. Thin eggshells have become prevalent among certain declining species of predatory birds. Shell thinning and associated reproductive effects have been produced experimentally in mallard ducks and in sparrow hawks. Coturnix quail fed dietary dosages of p,p'-DDT produced fewer eggs than did untreated birds and the eggs had thinner shells. Hatchability was not significantly altered. Comparisons between these results and those obtained in other studies indicate significant species differences.

  18. Cortical thinning in psychopathy

    PubMed Central

    Ly, Martina; Motzkin, Julian C.; Philippi, Carissa L.; Kirk, Gregory R.; Newman, Joseph P.; Kiehl, Kent A.; Koenigs, Michael

    2013-01-01

    Objective Psychopathy is a personality disorder associated with severely antisocial behavior and a host of cognitive and affective deficits. The neuropathological basis of the disorder has not been clearly established. Cortical thickness is a sensitive measure of brain structure that has been used to identify neurobiological abnormalities in a number of psychiatric disorders. The purpose of this study is to evaluate cortical thickness and corresponding functional connectivity in criminal psychopaths. Method Using T1 MRI data, we computed cortical thickness maps in a sample of adult male prison inmates selected based on psychopathy diagnosis (n=21 psychopathic inmates, n=31 non-psychopathic inmates). Using rest-fMRI data from a subset of these inmates (n=20 psychopathic inmates, n=20 non-psychopathic inmates), we then computed functional connectivity within networks exhibiting significant thinning among psychopaths. Results Relative to non-psychopaths, psychopaths exhibited significantly thinner cortex in a number of regions, including left insula and dorsal anterior cingulate cortex, bilateral precentral gyrus, bilateral anterior temporal cortex, and right inferior frontal gyrus. These neurostructural differences were not due to differences in age, IQ, or substance abuse. Psychopaths also exhibited a corresponding reduction in functional connectivity between left insula and left dorsal anterior cingulate cortex. Conclusions Psychopathy is associated with a distinct pattern of cortical thinning and reduced functional connectivity. PMID:22581200

  19. Thin film mechanics

    NASA Astrophysics Data System (ADS)

    Cooper, Ryan C.

    This doctoral thesis details the methods of determining mechanical properties of two classes of novel thin films suspended two-dimensional crystals and electron beam irradiated microfilms of polydimethylsiloxane (PDMS). Thin films are used in a variety of surface coatings to alter the opto-electronic properties or increase the wear or corrosion resistance and are ideal for micro- and nanoelectromechanical system fabrication. One of the challenges in fabricating thin films is the introduction of strains which can arise due to application techniques, geometrical conformation, or other spurious conditions. Chapters 2-4 focus on two dimensional materials. This is the intrinsic limit of thin films-being constrained to one atomic or molecular unit of thickness. These materials have mechanical, electrical, and optical properties ideal for micro- and nanoelectromechanical systems with truly novel device functionality. As such, the breadth of applications that can benefit from a treatise on two dimensional film mechanics is reason enough for exploration. This study explores the anomylously high strength of two dimensional materials. Furthermore, this work also aims to bridge four main gaps in the understanding of material science: bridging the gap between ab initio calculations and finite element analysis, bridging the gap between ab initio calculations and experimental results, nanoscale to microscale, and microscale to mesoscale. A nonlinear elasticity model is used to determine the necessary elastic constants to define the strain-energy density function for finite strain. Then, ab initio calculations-density functional theory-is used to calculate the nonlinear elastic response. Chapter 2 focuses on validating this methodology with atomic force microscope nanoindentation on molybdenum disulfide. Chapter 3 explores the convergence criteria of three density functional theory solvers to further verify the numerical calculations. Chapter 4 then uses this model to investigate

  20. Stability of a velocity field tangential discontinuity in a three-layer density-stratified liquid with a moving middle layer

    NASA Astrophysics Data System (ADS)

    Shiryaeva, S. O.; Grigor'ev, A. I.

    2016-04-01

    A dispersion relation is analytically derived for gravitational waves in an ideal incompressible threelayer liquid with a free surface in the presence of a velocity field tangential discontinuity between the layers. The discontinuity results from the motion of the middle layer. The instability of the tangential discontinuity is shown to depend on the relative velocity of contacting layers, which, in turn, depends on the ratio of their densities. The closer the density ratio to unity, the lower the moving layer velocity causing instability. In the given case, instability involves internal waves arising at the second and third interfaces in accordance with the Kelvin-Helmholtz concept of instability development. Internal waves with wavelengths far exceeding the thickness of the middle layer are found to interact with each other. Surface waves only change their frequencies.

  1. Thin film atomic hydrogen detectors

    NASA Technical Reports Server (NTRS)

    Gruber, C. L.

    1977-01-01

    Thin film and bead thermistor atomic surface recombination hydrogen detectors were investigated both experimentally and theoretically. Devices were constructed on a thin Mylar film substrate. Using suitable Wheatstone bridge techniques sensitivities of 80 microvolts/2x10 to the 13th power atoms/sec are attainable with response time constants on the order of 5 seconds.

  2. Polysilicon thin films and interfaces

    SciTech Connect

    Kamins, T. ); Raicu, B. ); Thompson, C.V. )

    1990-01-01

    This volume contains the proceedings of a symposium on polysilicon thin films and interfaces, held as part of the 1990 Materials Research Society Spring Meeting. Topics covered include: crystal grown fo silicon and germanium wafers for photovoltaic devices, microanalysis of tungsten silicide interface, thermal processing of polysilicon thin films, and electrical and optical properties of polysilicon sheets for photovoltaic devices.

  3. Thin film ion conducting coating

    DOEpatents

    Goldner, Ronald B.; Haas, Terry; Wong, Kwok-Keung; Seward, George

    1989-01-01

    Durable thin film ion conducting coatings are formed on a transparent glass substrate by the controlled deposition of the mixed oxides of lithium:tantalum or lithium:niobium. The coatings provide durable ion transport sources for thin film solid state storage batteries and electrochromic energy conservation devices.

  4. Thin wire pointing method

    NASA Technical Reports Server (NTRS)

    Green, G.; Mattauch, R. J. (Inventor)

    1983-01-01

    A method is described for forming sharp tips on thin wires, in particular phosphor bronze wires of diameters such as one-thousandth inch used to contact micron size Schottky barrier diodes, which enables close control of tip shape and which avoids the use of highly toxic solutions. The method includes dipping an end of a phosphor bronze wire into a dilute solution of sulfamic acid and applying a current through the wire to electrochemically etch it. The humidity in the room is controlled to a level of less than 50%, and the voltage applied between the wire and another electrode in the solutions is a half wave rectified voltage. The current through the wire is monitored, and the process is stopped when the current falls to a predetermined low level.

  5. Polycrystalline thin films

    NASA Astrophysics Data System (ADS)

    Zweibel, K.; Mitchell, R.; Ullal, H.

    1987-02-01

    This annual report for fiscal year 1986 summarizes the status, accomplishments, and projected future research directions of the Polycrystalline Thin Film Task in the Photovoltaic Program Branch of the Solar Energy Research Institute's Solar Electric Research Division. Subcontracted work in this area has concentrated on the development of CuInSe2 and CdTe technologies. During FY 1986, major progress was achieved by subcontractors in (1) achieving 10.5% (SERI-verified) efficiency with CdTe, (2) improving the efficiency of selenized CuInSe2 solar cells to nearly 8%, and (3) developing a transparent contact to CdTe cells for potential use in the top cells of tandem structures.

  6. Polyimide Aerogel Thin Films

    NASA Technical Reports Server (NTRS)

    Meador, Mary Ann; Guo, Haiquan

    2012-01-01

    Polyimide aerogels have been crosslinked through multifunctional amines. This invention builds on "Polyimide Aerogels With Three-Dimensional Cross-Linked Structure," and may be considered as a continuation of that invention, which results in a polyimide aerogel with a flexible, formable form. Gels formed from polyamic acid solutions, end-capped with anhydrides, and cross-linked with the multifunctional amines, are chemically imidized and dried using supercritical CO2 extraction to give aerogels having density around 0.1 to 0.3 g/cubic cm. The aerogels are 80 to 95% porous, and have high surface areas (200 to 600 sq m/g) and low thermal conductivity (as low as 14 mW/m-K at room temperature). Notably, the cross-linked polyimide aerogels have higher modulus than polymer-reinforced silica aerogels of similar density, and can be fabricated as both monoliths and thin films.

  7. Selective inorganic thin films

    SciTech Connect

    Phillips, M.L.F.; Weisenbach, L.A.; Anderson, M.T.

    1995-05-01

    This project is developing inorganic thin films as membranes for gas separation applications, and as discriminating coatings for liquid-phase chemical sensors. Our goal is to synthesize these coatings with tailored porosity and surface chemistry on porous substrates and on acoustic and optical sensors. Molecular sieve films offer the possibility of performing separations involving hydrogen, air, and natural gas constituents at elevated temperatures with very high separation factors. We are focusing on improving permeability and molecular sieve properties of crystalline zeolitic membranes made by hydrothermally reacting layered multicomponent sol-gel films deposited on mesoporous substrates. We also used acoustic plate mode (APM) oscillator and surface plasmon resonance (SPR) sensor elements as substrates for sol-gel films, and have both used these modified sensors to determine physical properties of the films and have determined the sensitivity and selectivity of these sensors to aqueous chemical species.

  8. Ferromagnetic thin films

    DOEpatents

    Krishnan, Kannan M.

    1994-01-01

    A ferromagnetic .delta.-Mn.sub.1-x Ga.sub.x thin film having perpendicular anisotropy is described which comprises: (a) a GaAs substrate, (b) a layer of undoped GaAs overlying said substrate and bonded thereto having a thickness ranging from about 50 to about 100 nanometers, (c) a layer of .delta.-Mn.sub.1-x Ga.sub.x overlying said layer of undoped GaAs and bonded thereto having a thickness ranging from about 20 to about 30 nanometers, and (d) a layer of GaAs overlying said layer of .delta.-Mn.sub.1-x Ga.sub.x and bonded thereto having a thickness ranging from about 2 to about 5 nanometers, wherein x is 0.4 .+-.0.05.

  9. Ferromagnetic thin films

    DOEpatents

    Krishnan, K.M.

    1994-12-20

    A ferromagnetic [delta]-Mn[sub 1[minus]x]Ga[sub x] thin film having perpendicular anisotropy is described which comprises: (a) a GaAs substrate, (b) a layer of undoped GaAs overlying said substrate and bonded thereto having a thickness ranging from about 50 to about 100 nanometers, (c) a layer of [delta]-Mn[sub 1[minus]x]Ga[sub x] overlying said layer of undoped GaAs and bonded thereto having a thickness ranging from about 20 to about 30 nanometers, and (d) a layer of GaAs overlying said layer of [delta]-Mn[sub 1[minus]x]Ga[sub x] and bonded thereto having a thickness ranging from about 2 to about 5 nanometers, wherein x is 0.4[+-]0.05. 7 figures.

  10. Nonlinear optical thin films

    NASA Technical Reports Server (NTRS)

    Leslie, Thomas M.

    1993-01-01

    A focused approach to development and evaluation of organic polymer films for use in optoelectronics is presented. The issues and challenges that are addressed include: (1) material synthesis, purification, and the tailoring of the material properties; (2) deposition of uniform thin films by a variety of methods; (3) characterization of material physical properties (thermal, electrical, optical, and electro-optical); and (4) device fabrication and testing. Photonic materials, devices, and systems were identified as critical technology areas by the Department of Commerce and the Department of Defense. This approach offers strong integration of basic material issues through engineering applications by the development of materials that can be exploited as the active unit in a variety of polymeric thin film devices. Improved materials were developed with unprecedented purity and stability. The absorptive properties can be tailored and controlled to provide significant improvement in propagation losses and nonlinear performance. Furthermore, the materials were incorporated into polymers that are highly compatible with fabrication and patterning processes for integrated optical devices and circuits. By simultaneously addressing the issues of materials development and characterization, keeping device design and fabrication in mind, many obstacles were overcome for implementation of these polymeric materials and devices into systems. We intend to considerably improve the upper use temperature, poling stability, and compatibility with silicon based devices. The principal device application that was targeted is a linear electro-optic modulation etalon. Organic polymers need to be properly designed and coupled with existing integrated circuit technology to create new photonic devices for optical communication, image processing, other laser applications such as harmonic generation, and eventually optical computing. The progression from microscopic sample to a suitable film

  11. Host thin films incorporating nanoparticles

    NASA Astrophysics Data System (ADS)

    Qureshi, Uzma

    The focus of this research project was the investigation of the functional properties of thin films that incorporate a secondary nanoparticulate phase. In particular to assess if the secondary nanoparticulate material enhanced a functional property of the coating on glass. In order to achieve this, new thin film deposition methods were developed, namely use of nanopowder precursors, an aerosol assisted transport technique and an aerosol into atmospheric pressure chemical vapour deposition system. Aerosol assisted chemical vapour deposition (AACVD) was used to deposit 8 series of thin films on glass. Five different nanoparticles silver, gold, ceria, tungsten oxide and zinc oxide were tested and shown to successfully deposit thin films incorporating nanoparticles within a host matrix. Silver nanoparticles were synthesised and doped within a titania film by AACVD. This improved solar control properties. A unique aerosol assisted chemical vapour deposition (AACVD) into atmospheric pressure chemical vapour deposition (APCVD) system was used to deposit films of Au nanoparticles and thin films of gold nanoparticles incorporated within a host titania matrix. Incorporation of high refractive index contrast metal oxide particles within a host film altered the film colour. The key goal was to test the potential of nanopowder forms and transfer the suspended nanopowder via an aerosol to a substrate in order to deposit a thin film. Discrete tungsten oxide nanoparticles or ceria nanoparticles within a titanium dioxide thin film enhanced the self-cleaning and photo-induced super-hydrophilicity. The nanopowder precursor study was extended by deposition of zinc oxide thin films incorporating Au nanoparticles and also ZnO films deposited from a ZnO nanopowder precursor. Incorporation of Au nanoparticles within a VO: host matrix improved the thermochromic response, optical and colour properties. Composite VC/TiC and Au nanoparticle/V02/Ti02 thin films displayed three useful

  12. Learning unit: Thin lenses

    NASA Astrophysics Data System (ADS)

    Nita, L.-S.

    2012-04-01

    Learning unit: Thin lenses "Why objects seen through lenses are sometimes upright and sometimes reversed" Nita Laura Simona National College of Arts and Crafts "Constantin Brancusi", Craiova, Romania 1. GEOMETRIC OPTICS. 13 hours Introduction (models, axioms, principles, conventions) 1. Thin lenses (Types of lenses. Defining elements. Path of light rays through lenses. Image formation. Required physical quantities. Lens formulas). 2. Lens systems (Non-collated lenses. Focalless systems). 3. Human eye (Functioning as an optical system. Sight defects and their corrections). 4. Optical instruments (Characteristics exemplified by a magnifying glass. Paths of light rays through a simplified photo camera. Path of light rays through a classical microscope) (Physics curriculum for the IXth grade/ 2011). This scenario exposes a learning unit based on experimental sequences (defining specific competencies), as a succession of lessons started by noticing a problem whose solution assumes the setup of an experiment under laboratory conditions. Progressive learning of theme objectives are realised with sequential experimental steps. The central cognitive process is the induction or the generalization (development of new knowledge based on observation of examples or counterexamples of the concept to be learnt). Pupil interest in theme objectives is triggered by problem-situations, for example: "In order to better see small objects I need a magnifying glass. But when using a magnifier, small object images are sometimes seen upright and sometimes seen reversed!" Along the way, pupils' reasoning will converge to the idea: "The image of an object through a lens depends on the relative distances among object, lens, and observer". Associated learning model: EXPERIMENT Specific competencies: derived from the experiment model, in agreement with the following learning unit steps I. Evoking - Anticipation: Size of the problem, formulation of hypotheses and planning of experiment. II

  13. Chiral atomically thin films

    NASA Astrophysics Data System (ADS)

    Kim, Cheol-Joo; Sánchez-Castillo, A.; Ziegler, Zack; Ogawa, Yui; Noguez, Cecilia; Park, Jiwoong

    2016-06-01

    Chiral materials possess left- and right-handed counterparts linked by mirror symmetry. These materials are useful for advanced applications in polarization optics, stereochemistry and spintronics. In particular, the realization of spatially uniform chiral films with atomic-scale control of their handedness could provide a powerful means for developing nanodevices with novel chiral properties. However, previous approaches based on natural or grown films, or arrays of fabricated building blocks, could not offer a direct means to program intrinsic chiral properties of the film on the atomic scale. Here, we report a chiral stacking approach, where two-dimensional materials are positioned layer-by-layer with precise control of the interlayer rotation (θ) and polarity, resulting in tunable chiral properties of the final stack. Using this method, we produce left- and right-handed bilayer graphene, that is, a two-atom-thick chiral film. The film displays one of the highest intrinsic ellipticity values (6.5 deg μm–1) ever reported, and a remarkably strong circular dichroism (CD) with the peak energy and sign tuned by θ and polarity. We show that these chiral properties originate from the large in-plane magnetic moment associated with the interlayer optical transition. Furthermore, we show that we can program the chiral properties of atomically thin films layer-by-layer by producing three-layer graphene films with structurally controlled CD spectra.

  14. Chiral atomically thin films.

    PubMed

    Kim, Cheol-Joo; Sánchez-Castillo, A; Ziegler, Zack; Ogawa, Yui; Noguez, Cecilia; Park, Jiwoong

    2016-06-01

    Chiral materials possess left- and right-handed counterparts linked by mirror symmetry. These materials are useful for advanced applications in polarization optics, stereochemistry and spintronics. In particular, the realization of spatially uniform chiral films with atomic-scale control of their handedness could provide a powerful means for developing nanodevices with novel chiral properties. However, previous approaches based on natural or grown films, or arrays of fabricated building blocks, could not offer a direct means to program intrinsic chiral properties of the film on the atomic scale. Here, we report a chiral stacking approach, where two-dimensional materials are positioned layer-by-layer with precise control of the interlayer rotation (θ) and polarity, resulting in tunable chiral properties of the final stack. Using this method, we produce left- and right-handed bilayer graphene, that is, a two-atom-thick chiral film. The film displays one of the highest intrinsic ellipticity values (6.5 deg μm(-1)) ever reported, and a remarkably strong circular dichroism (CD) with the peak energy and sign tuned by θ and polarity. We show that these chiral properties originate from the large in-plane magnetic moment associated with the interlayer optical transition. Furthermore, we show that we can program the chiral properties of atomically thin films layer-by-layer by producing three-layer graphene films with structurally controlled CD spectra. PMID:26900756

  15. Interference Colors in Thin Films.

    ERIC Educational Resources Information Center

    Armstrong, H. L.

    1979-01-01

    Explains interference colors in thin films as being due to the removal, or considerable reduction, of a certain color by destructive inteference that results in the complementary color being seen. (GA)

  16. Thin, Flexible IMM Solar Array

    NASA Technical Reports Server (NTRS)

    Walmsley, Nicholas

    2015-01-01

    NASA needs solar arrays that are thin, flexible, and highly efficient; package compactly for launch; and deploy into large, structurally stable high-power generators. Inverted metamorphic multijunction (IMM) solar cells can enable these arrays, but integration of this thin crystalline cell technology presents certain challenges. The Thin Hybrid Interconnected Solar Array (THINS) technology allows robust and reliable integration of IMM cells into a flexible blanket comprising standardized modules engineered for easy production. The modules support the IMM cell by using multifunctional materials for structural stability, shielding, coefficient of thermal expansion (CTE) stress relief, and integrated thermal and electrical functions. The design approach includes total encapsulation, which benefits high voltage as well as electrostatic performance.

  17. Simplified Propagation of Uncertainty in the Non-Keplerian Problem

    NASA Astrophysics Data System (ADS)

    Park, I.; Scheeres, D.

    2014-09-01

    A major topic in the field of space situational awareness is the accurate mapping of the uncertainty of an observed object; this has led to high precision modeling of orbital motion and their associated uncertainty propagation. A main purpose of our research is to explore how much precision is needed in describing the dynamical motion of a spacecraft to accurately map uncertainty. To do this, we define an analytical simplified dynamical system (SDS) and probe the relation between accuracy and precision in uncertainty propagation. The use of an analytical theory that is precise enough can have significant savings in computation time. In this research, our SDS is developed based on analytic solutions found by applying the Deprit-Hori Lie transformation theory. An analytic approach has an advantage in that it can give more insight into how the short-period variations influence the uncertainty propagation as well as provide more efficient computation. The SDS includes multiple perturbations caused by the oblate Earth, gravitational attraction of a third-body, and solar radiation pressure (SRP). An artificial satellite in a Medium-Earth-Orbit (MEO) is chosen to magnify perturbing effects due to the third-body and SRP relative to the Earth oblateness. A reference uncertainty is generated through Monte-Carlo simulations based on the full dynamical system. The accuracy of the SDS is verified through two statistical methods: 1) comparison of the central moments of the probability density function, 2) statistical energy test. Improvements in computational efficiency are investigated by comparing two factors: 1) number of function calls, 2) computation time. In summary, we derive approximate analytic solutions including multiple perturbations, and then define the SDS from them for a satellite in the MEO region. We verify the accuracy of the uncertainty propagation with the SDS by applying two statistical methods as well as show improvements in the computational efficiency of this approach.

  18. Thin EFG octagons

    NASA Astrophysics Data System (ADS)

    Kalejs, J. P.

    1994-01-01

    Mobil Solar Energy Corporation currently practices a unique crystal growth technology for producing crystalline silicon sheet, which is then cut with lasers into wafers. The wafers are processed into solar cells and incorporated into modules for photovoltaic applications. The silicon sheet is produced using a method known as Edge-defined Film-fed growth (EFG), in the form of hollow eight-sided polygons (octagons) with 10 cm faces. These are grown to lengths of 5 meters and thickness of 300 microns, with continuous melt replenishment, in compact furnaces designed to operate at a high sheet area production area of 135 sq cm/min. The present Photovoltaic Manufacturing Technology (PVMaT) three-year program seeks to advance the manufacturing line capabilities of the Mobil Solar crystal growth and cutting technologies. If successful, these advancements will provide significant reductions in already low silicon raw material usage, improve process productivity, laser cutting throughput and yield, and so lower both individual wafer cost and the cost of module production. This report summarizes the significant technical improvements in EFG technology achieved in Phase 1 of this program. Technical results are reported for each of the three main program areas: (1) thin octagon growth (crystal growth) -- to reduce the thickness of the octagon to an interim goal of 250 microns during Phase 1, with an ultimate goal of achieving 200 micron thicknesses; (2) laser cutting -- to improve the laser cutting process, so as to produce wafers with decreased laser cutting damage at increased wafer throughput rates; and (3) process control and product specification -- to implement advanced strategies in crystal growth process control and productivity designed to increase wafer yields.

  19. Thin film cell development workshop report

    NASA Technical Reports Server (NTRS)

    Woodyard, James R.

    1991-01-01

    The Thin Film Development Workshop provided an opportunity for those interested in space applications of thin film cells to debate several topics. The unique characteristics of thin film cells as well as a number of other issues were covered during the discussions. The potential of thin film cells, key research and development issues, manufacturing issues, radiation damage, substrates, and space qualification of thin film cells were discussed.

  20. The endometrium in assisted reproductive technology: How thin is thin?

    PubMed Central

    Mahajan, Nalini; Sharma, S.

    2016-01-01

    A thin endometrium is encountered infrequently (2.4%) in assisted reproductive technology cycles. When it does occur it is a cause of concern as it is associated with lower implantation rate and pregnancy rate. Though pregnancies have been reported at 4 and 5 mm it is apparent that an endometrial thickness <6 mm is associated with a trend toward lower probability of pregnancy. Hormone replacement therapy – frozen embryo transfer (FET) cycles appear to give better results due to an improvement in endometrial receptivity (ER). The etiology of thin endometrium plays a significant part in its receptivity. A number of treatments have been tried to improve endometrial growth, but none has been validated so far. Confirming ER of a thin endometrium by an ER array test before FET offers reassurance. PMID:27110071

  1. Line-driven ablation of circumstellar discs – I. Optically thin decretion discs of classical Oe/Be stars

    PubMed Central

    Kee, Nathaniel Dylan; Owocki, Stanley; Sundqvist, J. O.

    2016-01-01

    The extreme luminosities of massive, hot OB stars drive strong stellar winds through line-scattering of the star's UV continuum radiation. For OB stars with an orbiting circumstellar disc, we explore here the effect of such line-scattering in driving an ablation of material from the disc's surface layers, with initial focus on the marginally optically thin decretion discs of classical Oe and Be stars. For this we apply a multidimensional radiation-hydrodynamics code that assumes simple optically thin ray tracing for the stellar continuum, but uses a multiray Sobolev treatment of the line transfer; this fully accounts for the efficient driving by non-radial rays, due to desaturation of line-absorption by velocity gradients associated with the Keplerian shear in the disc. Results show a dense, intermediate-speed surface ablation, consistent with the strong, blueshifted absorption of UV wind lines seen in Be shell stars that are observed from near the disc plane. A key overall result is that, after an initial adjustment to the introduction of the disc, the asymptotic disc destruction rate is typically just an order-unity factor times the stellar wind mass-loss rate. For optically thin Be discs, this leads to a disc destruction time of order months to years, consistent with observationally inferred disc decay times. The much stronger radiative forces of O stars reduce this time to order days, making it more difficult for decretion processes to sustain a disc in earlier spectral types, and so providing a natural explanation for the relative rarity of Oe stars in the Galaxy. Moreover, the decrease in line-driving at lower metallicity implies both a reduction in the winds that help spin-down stars from near-critical rotation, and a reduction in the ablation of any decretion disc; together these provide a natural explanation for the higher fraction of classical Be stars, as well as the presence of Oe stars, in the lower metallicity Magellanic Clouds. We conclude with a

  2. Line-driven ablation of circumstellar discs - I. Optically thin decretion discs of classical Oe/Be stars

    NASA Astrophysics Data System (ADS)

    Kee, Nathaniel Dylan; Owocki, Stanley; Sundqvist, J. O.

    2016-05-01

    The extreme luminosities of massive, hot OB stars drive strong stellar winds through line-scattering of the star's UV continuum radiation. For OB stars with an orbiting circumstellar disc, we explore here the effect of such line-scattering in driving an ablation of material from the disc's surface layers, with initial focus on the marginally optically thin decretion discs of classical Oe and Be stars. For this we apply a multidimensional radiation-hydrodynamics code that assumes simple optically thin ray tracing for the stellar continuum, but uses a multiray Sobolev treatment of the line transfer; this fully accounts for the efficient driving by non-radial rays, due to desaturation of line-absorption by velocity gradients associated with the Keplerian shear in the disc. Results show a dense, intermediate-speed surface ablation, consistent with the strong, blueshifted absorption of UV wind lines seen in Be shell stars that are observed from near the disc plane. A key overall result is that, after an initial adjustment to the introduction of the disc, the asymptotic disc destruction rate is typically just an order-unity factor times the stellar wind mass-loss rate. For optically thin Be discs, this leads to a disc destruction time of order months to years, consistent with observationally inferred disc decay times. The much stronger radiative forces of O stars reduce this time to order days, making it more difficult for decretion processes to sustain a disc in earlier spectral types, and so providing a natural explanation for the relative rarity of Oe stars in the Galaxy. Moreover, the decrease in line-driving at lower metallicity implies both a reduction in the winds that help spin-down stars from near-critical rotation, and a reduction in the ablation of any decretion disc; together these provide a natural explanation for the higher fraction of classical Be stars, as well as the presence of Oe stars, in the lower metallicity Magellanic Clouds. We conclude with a

  3. Thin-film metal hydrides.

    PubMed

    Remhof, Arndt; Borgschulte, Andreas

    2008-12-01

    The goal of the medieval alchemist, the chemical transformation of common metals into nobel metals, will forever be a dream. However, key characteristics of metals, such as their electronic band structure and, consequently, their electric, magnetic and optical properties, can be tailored by controlled hydrogen doping. Due to their morphology and well-defined geometry with flat, coplanar surfaces/interfaces, novel phenomena may be observed in thin films. Prominent examples are the eye-catching hydrogen switchable mirror effect, the visualization of solid-state diffusion and the formation of complex surface morphologies. Thin films do not suffer as much from embrittlement and/or decrepitation as bulk materials, allowing the study of cyclic absorption and desorption. Therefore, thin-metal hydride films are used as model systems to study metal-insulator transitions, for high throughput combinatorial research or they may be used as indicator layers to study hydrogen diffusion. They can be found in technological applications as hydrogen sensors, in electrochromic and thermochromic devices. In this review, we discuss the effect of hydrogen loading of thin niobium and yttrium films as archetypical examples of a transition metal and a rare earth metal, respectively. Our focus thereby lies on the hydrogen induced changes of the electronic structure and the morphology of the thin films, their optical properties, the visualization and the control of hydrogen diffusion and on the study of surface phenomena and catalysis. PMID:18980236

  4. Obese people's perceptions of the thin ideal.

    PubMed

    Couch, Danielle; Thomas, Samantha L; Lewis, Sophie; Blood, R Warwick; Holland, Kate; Komesaroff, Paul

    2016-01-01

    The media play a key role in promoting the thin ideal. A qualitative study, in which we used in depth interviews and thematic analysis, was undertaken to explore the attitudes of 142 obese individuals toward media portrayals of the thin ideal. Participants discussed the thin ideal as a social norm that is also supported through the exclusion of positive media portrayals of obese people. They perceived the thin ideal as an 'unhealthy' mode of social control, reflecting on their personal experiences and their concerns for others. Participants' perceptions highlighted the intersections between the thin ideal and gender, grooming and consumerism. Participants' personal responses to the thin ideal were nuanced--some were in support of the thin ideal and some were able to critically reflect and reject the thin ideal. We consider how the thin ideal may act as a form of synoptical social control, working in tandem with wider public health panoptical surveillance of body weight. PMID:26685706

  5. Thin metal electrode for AMTEC

    NASA Technical Reports Server (NTRS)

    Williams, Roger M. (Inventor); Wheeler, Bob L. (Inventor); Jefferies-Nakamura, Barbara (Inventor); Lamb, James L. (Inventor); Bankston, C. Perry (Inventor); Cole, Terry (Inventor)

    1989-01-01

    An electrode having higher power output is formed of a thin, porous film (less than 1 micrometer) applied to a beta-alumina solid electrolyte (BASE). The electrode includes an open grid, current collector such as a series of thin, parallel, grid lines applied to the thin film and a plurality of cross-members such as loop of metal wire surrounding the BASE tube. The loops are electrically connected by a bus wire. The overall impedance of the electrode considering both the contributions from the bulk BASE and the porous electrode BASE interface is low, about 0.5 OHM/cm.sup.2 and power densities of over 0.3 watt/cm.sup.2 for extended periods.

  6. Squirming through shear thinning fluids

    NASA Astrophysics Data System (ADS)

    Datt, Charu; Zhu, Lailai; Elfring, Gwynn J.; Pak, On Shun

    2015-11-01

    Many microorganisms find themselves surrounded by fluids which are non-Newtonian in nature; human spermatozoa in female reproductive tract and motile bacteria in mucosa of animals are common examples. These biological fluids can display shear-thinning rheology whose effects on the locomotion of microorganisms remain largely unexplored. Here we study the self-propulsion of a squirmer in shear-thinning fluids described by the Carreau-Yasuda model. The squirmer undergoes surface distortions and utilizes apparent slip-velocities around its surface to swim through a fluid medium. In this talk, we will discuss how the nonlinear rheological properties of a shear-thinning fluid affect the propulsion of a swimmer compared with swimming in Newtonian fluids.

  7. [Obesity and thinness in painting].

    PubMed

    Schüller Pérez, Amador

    2004-01-01

    The obesity, serious frequenty sanitary problem, cause of complications that effects to the expectation of life, with aesthetic repercussion and with an increase in the last decades. Admitted the obesity android, gynoide, central or abdominal, wide aesthetic repercussion and physiopathologic like hyperdislipemias, metabolic alterations (diabetes mellitus, etc...), arterial hypertension, column arthrosis and outlying. Ethiopathologics co-factors, sedentariness, genotypic predisposition, endocrine alterations and of the leptina secretion. Illustrative cases of obesity in the painting of those that characteristic models are exposed, from slight grades to intense affecting to both genders. The thinness counterpoint of the obesity, multicausal process, less frequent than the obesity with aesthetic and psychological repercussion. It is the formed aesthetic thinness to the diverse types physiopathologic, without forgetting the constitutional and family form and the anorexy, the serial ones to disasters, wars, famines, etc..., the mystic thinness of saints and ascetics, and the serial one to consuming processes. PMID:15997591

  8. About Thinning Invariant Partition Structures

    NASA Astrophysics Data System (ADS)

    Starr, Shannon; Vermesi, Brigitta; Wei, Ang

    2012-08-01

    Bernoulli- p thinning has been well-studied for point processes. Here we consider three other cases: (1) sequences ( X 1, X 2,…); (2) gaps of such sequences ( X n+1- X 1) n∈ℕ; (3) partition structures. For the first case we characterize the distributions which are simultaneously invariant under Bernoulli- p thinning for all p∈(0,1]. Based on this, we make conjectures for the latter two cases, and provide a potential approach for proof. We explain the relation to spin glasses, which is complementary to important previous work of Aizenman and Ruzmaikina, Arguin, and Shkolnikov.

  9. Vapor deposition of thin films

    DOEpatents

    Smith, David C.; Pattillo, Stevan G.; Laia, Jr., Joseph R.; Sattelberger, Alfred P.

    1992-01-01

    A highly pure thin metal film having a nanocrystalline structure and a process of preparing such highly pure thin metal films of, e.g., rhodium, iridium, molybdenum, tungsten, rhenium, platinum, or palladium by plasma assisted chemical vapor deposition of, e.g., rhodium(allyl).sub.3, iridium(allyl).sub.3, molybdenum(allyl).sub.4, tungsten(allyl).sub.4, rhenium(allyl).sub.4, platinum(allyl).sub.2, or palladium(allyl).sub.2 are disclosed. Additionally, a general process of reducing the carbon content of a metallic film prepared from one or more organometallic precursor compounds by plasma assisted chemical vapor deposition is disclosed.

  10. Thin film polymeric gel electrolytes

    DOEpatents

    Derzon, D.K.; Arnold, C. Jr.; Delnick, F.M.

    1996-12-31

    Novel hybrid thin film electrolytes, based on an organonitrile solvent system, which are compositionally stable, environmentally safe, can be produced efficiently in large quantity and which, because of their high conductivities {approx_equal}10{sup {minus}3}{Omega}{sup {minus}1} cm{sup {minus}1} are useful as electrolytes for rechargeable lithium batteries. 1 fig.

  11. Calorimetry of epitaxial thin films.

    PubMed

    Cooke, David W; Hellman, F; Groves, J R; Clemens, B M; Moyerman, S; Fullerton, E E

    2011-02-01

    Thin film growth allows for the manipulation of material on the nanoscale, making possible the creation of metastable phases not seen in the bulk. Heat capacity provides a direct way of measuring thermodynamic properties of these new materials, but traditional bulk calorimetric techniques are inappropriate for such a small amount of material. Microcalorimetry and nanocalorimetry techniques exist for the measurements of thin films but rely on an amorphous membrane platform, limiting the types of films which can be measured. In the current work, ion-beam-assisted deposition is used to provide a biaxially oriented MgO template on a suspended membrane microcalorimeter in order to measure the specific heat of epitaxial thin films. Synchrotron x-ray diffraction showed the biaxial order of the MgO template. X-ray diffraction was also used to prove the high quality of epitaxy of a film grown onto this MgO template. The contribution of the MgO layer to the total heat capacity was measured to be just 6.5% of the total addenda contribution. The heat capacity of a Fe(.49)Rh(.51) film grown epitaxially onto the device was measured, comparing favorably to literature data on bulk crystals. This shows the viability of the MgO∕SiN(x)-membrane-based microcalorimeter as a way of measuring the thermodynamic properties of epitaxial thin films. PMID:21361612

  12. Some Experiments with Thin Prisms.

    ERIC Educational Resources Information Center

    Fernando, P. C. B.

    1980-01-01

    Described are several experiments, for a course in geometrical optics or for a college physics laboratory, which have a bearing on ophthalmic optics. Experiments include the single thin prism, crossed prisms, and the prismatic power of a lens. (Author/DS)

  13. Thin Film Solid Lubricant Development

    NASA Technical Reports Server (NTRS)

    Benoy, Patricia A.

    1997-01-01

    Tribological coatings for high temperature sliding applications are addressed. A sputter-deposited bilayer coating of gold and chromium is investigated as a potential solid lubricant for protection of alumina substrates during sliding at high temperature. Evaluation of the tribological properties of alumina pins sliding against thin sputtered gold films on alumina substrates is presented.

  14. High Performance Thin Layer Chromatography.

    ERIC Educational Resources Information Center

    Costanzo, Samuel J.

    1984-01-01

    Clarifies where in the scheme of modern chromatography high performance thin layer chromatography (TLC) fits and why in some situations it is a viable alternative to gas and high performance liquid chromatography. New TLC plates, sample applications, plate development, and instrumental techniques are considered. (JN)

  15. New strategies for thinning peaches

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An evaluation of two mechanical thinners was conducted in four commercial peach orchard blocks in 2007. A mechanical blossom thinner designed by a German grower for thinning apple trees that employed nylon cords (strings) to remove blossoms was tested on peach trees trained to either a perpendicula...

  16. Hybrid thin-film amplifier

    NASA Technical Reports Server (NTRS)

    Cleveland, G.

    1977-01-01

    Miniature amplifier for bioelectronic instrumentation consumes only about 100 mW and has frequency response flat to within 0.5 dB from 0.14 to 450 Hz. Device consists of five thin film substrates, which contain eight operational amplifiers and seven field-effect transistor dice.

  17. Thin film polymeric gel electrolytes

    DOEpatents

    Derzon, Dora K.; Arnold, Jr., Charles; Delnick, Frank M.

    1996-01-01

    Novel hybrid thin film electrolyte, based on an organonitrile solvent system, which are compositionally stable, environmentally safe, can be produced efficiently in large quantity and which, because of their high conductivities .apprxeq.10.sup.-3 .OMEGA..sup.-1 cm.sup.-1 are useful as electrolytes for rechargeable lithium batteries.

  18. Semiconductor-nanocrystal/conjugated polymer thin films

    DOEpatents

    Alivisatos, A. Paul; Dittmer, Janke J.; Huynh, Wendy U.; Milliron, Delia

    2014-06-17

    The invention described herein provides for thin films and methods of making comprising inorganic semiconductor-nanocrystals dispersed in semiconducting-polymers in high loading amounts. The invention also describes photovoltaic devices incorporating the thin films.

  19. On thinning of chains in MCMC

    USGS Publications Warehouse

    Link, William A.; Eaton, Mitchell J.

    2012-01-01

    4. We discuss the background and prevalence of thinning, illustrate its consequences, discuss circumstances when it might be regarded as a reasonable option and recommend against routine thinning of chains unless necessitated by computer memory limitations.

  20. Thin film-coated polymer webs

    DOEpatents

    Wenz, Robert P.; Weber, Michael F.; Arudi, Ravindra L.

    1992-02-04

    The present invention relates to thin film-coated polymer webs, and more particularly to thin film electronic devices supported upon a polymer web, wherein the polymer web is treated with a purifying amount of electron beam radiation.

  1. Semiconductor-nanocrystal/conjugated polymer thin films

    DOEpatents

    Alivisatos, A. Paul; Dittmer, Janke J.; Huynh, Wendy U.; Milliron, Delia

    2010-08-17

    The invention described herein provides for thin films and methods of making comprising inorganic semiconductor-nanocrystals dispersed in semiconducting-polymers in high loading amounts. The invention also describes photovoltaic devices incorporating the thin films.

  2. Low work function, stable thin films

    DOEpatents

    Dinh, Long N.; McLean, II, William; Balooch, Mehdi; Fehring, Jr., Edward J.; Schildbach, Marcus A.

    2000-01-01

    Generation of low work function, stable compound thin films by laser ablation. Compound thin films with low work function can be synthesized by simultaneously laser ablating silicon, for example, and thermal evaporating an alkali metal into an oxygen environment. For example, the compound thin film may be composed of Si/Cs/O. The work functions of the thin films can be varied by changing the silicon/alkali metal/oxygen ratio. Low work functions of the compound thin films deposited on silicon substrates were confirmed by ultraviolet photoelectron spectroscopy (UPS). The compound thin films are stable up to 500.degree. C. as measured by x-ray photoelectron spectroscopy (XPS). Tests have established that for certain chemical compositions and annealing temperatures of the compound thin films, negative electron affinity (NEA) was detected. The low work function, stable compound thin films can be utilized in solar cells, field emission flat panel displays, electron guns, and cold cathode electron guns.

  3. Thin films under chemical stress

    SciTech Connect

    Not Available

    1991-01-01

    The goal of work on this project has been develop a set of experimental tools to allow investigators interested in transport, binding, and segregation phenomena in composite thin film structures to study these phenomena in situ. Work to-date has focuses on combining novel spatially-directed optical excitation phenomena, e.g. waveguide eigenmodes in thin dielectric slabs, surface plasmon excitations at metal-dielectric interfaces, with standard spectroscopies to understand dynamic processes in thin films and at interfaces. There have been two main scientific thrusts in the work and an additional technical project. In one thrust we have sought to develop experimental tools which will allow us to understand the chemical and physical changes which take place when thin polymer films are placed under chemical stress. In principle this stress may occur because the film is being swelled by a penetrant entrained in solvent, because interfacial reactions are occurring at one or more boundaries within the film structure, or because some component of the film is responding to an external stimulus (e.g. pH, temperature, electric field, or radiation). However all work to-date has focused on obtaining a clearer understanding penetrant transport phenomena. The other thrust has addressed the kinetics of adsorption of model n-alkanoic acids from organic solvents. Both of these thrusts are important within the context of our long-term goal of understanding the behavior of composite structures, composed of thin organic polymer films interspersed with Langmuir-Blodgett (LB) and self-assembled monolayers. In addition there has been a good deal of work to develop the local technical capability to fabricate grating couplers for optical waveguide excitation. This work, which is subsidiary to the main scientific goals of the project, has been successfully completed and will be detailed as well. 41 refs., 10 figs.

  4. Polyimide thin-film dielectrics on ferroelectrics

    NASA Technical Reports Server (NTRS)

    Galiardi, R. V.

    1977-01-01

    Conducting layers of multi-layered thin-film ferroelectric device, such as is used in liquid crystal/ferroelectric display, can be electrically isolated using thin-film layer of polyimide. Ease of application and high electrical-breakdown strength allow dependable and economical means of providing dielectric for other thin-film microelectronic devices.

  5. Cut Costs with Thin Client Computing.

    ERIC Educational Resources Information Center

    Hartley, Patrick H.

    2001-01-01

    Discusses how school districts can considerably increase the number of administrative computers in their districts without a corresponding increase in costs by using the "Thin Client" component of the Total Cost of Ownership (TCC) model. TCC and Thin Client are described, including its software and hardware components. An example of a Thin Client…

  6. 7 CFR 29.3648 - Thin Leaf (C Group).

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... specifications, and tolerances C1L Choice Quality Light-brown Thin Leaf. Ripe, thin, open leaf structure, smooth... injury tolerance. C2L Fine Quality Light-brown Thin Leaf. Ripe, thin, open leaf structure, smooth, oily... tolerance. C4L Fair Quality Light-brown Thin Leaf. Mature, thin, close leaf structure, rough, lean in...

  7. 7 CFR 29.3648 - Thin Leaf (C Group).

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... specifications, and tolerances C1L Choice Quality Light-brown Thin Leaf. Ripe, thin, open leaf structure, smooth... injury tolerance. C2L Fine Quality Light-brown Thin Leaf. Ripe, thin, open leaf structure, smooth, oily... tolerance. C4L Fair Quality Light-brown Thin Leaf. Mature, thin, close leaf structure, rough, lean in...

  8. 7 CFR 29.3648 - Thin Leaf (C Group).

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... specifications, and tolerances C1L Choice Quality Light-brown Thin Leaf. Ripe, thin, open leaf structure, smooth... injury tolerance. C2L Fine Quality Light-brown Thin Leaf. Ripe, thin, open leaf structure, smooth, oily... tolerance. C4L Fair Quality Light-brown Thin Leaf. Mature, thin, close leaf structure, rough, lean in...

  9. 7 CFR 29.3648 - Thin Leaf (C Group).

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... specifications, and tolerances C1L Choice Quality Light-brown Thin Leaf. Ripe, thin, open leaf structure, smooth... injury tolerance. C2L Fine Quality Light-brown Thin Leaf. Ripe, thin, open leaf structure, smooth, oily... tolerance. C4L Fair Quality Light-brown Thin Leaf. Mature, thin, close leaf structure, rough, lean in...

  10. 7 CFR 29.2438 - Thin Leaf (C Group).

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Fair Light-brown Thin Leaf. Thin to medium body, mature to ripe, close, lean in oil, inelastic, weak... Light-brown Thin Leaf. Thin to medium body, mature to ripe, close, lean in oil, inelastic, weak, dull... Medium-brown Thin Leaf. Thin to medium body, mature to ripe, close, lean in oil, inelastic, weak,...

  11. 7 CFR 29.3648 - Thin Leaf (C Group).

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... tolerance. C4L Fair Quality Light-brown Thin Leaf. Mature, thin, close leaf structure, rough, lean in oil... tolerance. C5L Low Quality Light-brown Thin Leaf Underripe, thin, close leaf structure, rough, lean in oil... tolerance. C4F Fair Quality Medium-brown Thin Leaf. Mature, thin, close leaf structure, rough, lean in...

  12. 7 CFR 29.2663 - Thin Leaf (C Group).

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... tolerance. C4L Fair Light-brown Thin Leaf. Thin, mature, close, lean in oil, inelastic, weak, dull finish... Thin Leaf. Thin, mature, close, lean in oil, inelastic, weak, dull finish, pale color intensity, narrow... tolerance. C4F Fair Medium-brown Thin Leaf. Thin, mature, close, lean in oil, inelastic, weak, dull...

  13. Phase Coarsening in Thin Films

    NASA Astrophysics Data System (ADS)

    Wang, K. G.; Glicksman, M. E.

    2015-08-01

    Phase coarsening (Ostwald ripening) phenomena are ubiquitous in materials growth processes such as thin film formation. The classical theory explaining late-stage phase coarsening phenomena was developed by Lifshitz and Slyozov, and by Wagner in the 1960s. Their theory is valid only for a vanishing volume fraction of the second phase in three dimensions. However, phase coarsening in two-dimensional systems is qualitatively different from that in three dimensions. In this paper, the many-body concept of screening length is reviewed, from which we derive the growth law for a `screened' phase island, and develop diffusion screening theory for phase coarsening in thin films. The coarsening rate constant, maximum size of phase islands in films, and their size distribution function will be derived from diffusion screening theory. A critical comparison will be provided of prior coarsening concepts and improvements derived from screening approaches.

  14. [Ultra-thin transnasal esophagogastroduodenoscopy].

    PubMed

    Kawai, Takashi; Yamamoto, Kei; Fukuzawa, Mari; Sakai, Yoshihiro; Moriyasu, Fuminori

    2010-07-01

    It is reported that ultra-thin transnasal esophagogastroduodenoscopy (TN-EGD) reduces pharyngeal discomfort and is more tolerable for the patients. Ultra-thin transnasal endoscopy has been reported as inferior to transoral conventional EGD (TO-EGD) in terms of image quality, suction, air insufflation and lens washing, due to the smaller endoscope caliber. TN-EGD should be conducted slowly, with short distance observation, and also with image-enhanced endoscopy. With reference to image-enhanced endoscopy, chromoendoscopy method (indigocarmine) is suitable for gastric neoplasm, on the other hand optical digital method (NBI) and digital method (i-scan, FICE) is suitable for esophageal neoplasm. TN-EGD is applied in various gastrointestinal (GI) procedures such as percutaneous endoscopic gastrostomy, nasoenteric feeding tube placement, endoscopic retrograde cholangiopancreaticography with nasobiliary drainage, long intestinal tube placement in small bowel obstruction, esophageal manometry. PMID:20662204

  15. Thin film concentrator panel development

    NASA Astrophysics Data System (ADS)

    Zimmerman, D. K.

    1982-07-01

    The development and testing of a rigid panel concept that utilizes a thin film reflective surface for application to a low-cost point-focusing solar concentrator is discussed. It is shown that a thin film reflective surface is acceptable for use on solar concentrators, including 1500 F applications. Additionally, it is shown that a formed steel sheet substrate is a good choice for concentrator panels. The panel has good optical properties, acceptable forming tolerances, environmentally resistant substrate and stiffeners, and adaptability to low to mass production rates. Computer simulations of the concentrator optics were run using the selected reflector panel design. Experimentally determined values for reflector surface specularity and reflectivity along with dimensional data were used in the analysis. The simulations provided intercept factor and net energy into the aperture as a function of aperture size for different surface errors and pointing errors. Point source and Sun source optical tests were also performed.

  16. Fundamentals of thin solar cells

    SciTech Connect

    Yablonovitch, E.

    1995-08-01

    It is now widely recognized that thin solar cells can present certain advantages for performance and cost. This is particularly the case when light trapping in the semiconductor film is incorporated, as compensation for the diminished single path thickness of the solar cell. In a solar cell thinner than a minority carrier diffusion length, the current collection is of course very easy. More importantly the concentration of an equivalent number of carriers in a thinner volume results in a higher Free Energy, or open circuit voltage. This extra Free Energy may be regarded as due to the concentration factor, just as it would be for photons, electrons, or for any chemical species. The final advantage of a thin solar cell is in the diminished material usage, a factor of considerable importance when we consider the material cost of the high quality semiconductors which we hope to employ.

  17. Punching Holes in Thin Metals

    NASA Technical Reports Server (NTRS)

    Garcia, Richard; Foster, Derrell; Miranda, Valentino

    1987-01-01

    Simple punching tool used to make holes in thin metal sheets, without burrs and edge deformations. Tool used on such materials as stainless steel, nickel alloys, beryllium, copper, and aluminum, in thicknesses of 0.002 to 0.010 in. With new punch, hole size held to tolerance of 0.025 mm. Includes rubber punch extruding into hole in top plate, pushing out exposed portion of clamped metal sheet.

  18. Fastener for thin fragile materials

    NASA Technical Reports Server (NTRS)

    Sokol, S.

    1979-01-01

    Two-piece fastener is ideal for securing thin delicate parts that might be damaged by conventional fasteners, such as rivets or upset collars. Strength of new fastener approaches that of riveted connection. Easily fabricated, fastener consists of plastic button and spring-steel collar. Parts have large contact area to distribute loads on delicate assemblies and low profile so that they fit into narrow spaces. Fastener is suitable for materials ranging in density from sheet metal to fabric sandwiches.

  19. The Thin Oil Film Equation

    NASA Technical Reports Server (NTRS)

    Brown, James L.; Naughton, Jonathan W.

    1999-01-01

    A thin film of oil on a surface responds primarily to the wall shear stress generated on that surface by a three-dimensional flow. The oil film is also subject to wall pressure gradients, surface tension effects and gravity. The partial differential equation governing the oil film flow is shown to be related to Burgers' equation. Analytical and numerical methods for solving the thin oil film equation are presented. A direct numerical solver is developed where the wall shear stress variation on the surface is known and which solves for the oil film thickness spatial and time variation on the surface. An inverse numerical solver is also developed where the oil film thickness spatial variation over the surface at two discrete times is known and which solves for the wall shear stress variation over the test surface. A One-Time-Level inverse solver is also demonstrated. The inverse numerical solver provides a mathematically rigorous basis for an improved form of a wall shear stress instrument suitable for application to complex three-dimensional flows. To demonstrate the complexity of flows for which these oil film methods are now suitable, extensive examination is accomplished for these analytical and numerical methods as applied to a thin oil film in the vicinity of a three-dimensional saddle of separation.

  20. Scattering from Thin Dielectric Disks

    NASA Technical Reports Server (NTRS)

    Levine, D. M.; Schneider, A.; Lang, R. H.; Carter, H. G.

    1984-01-01

    A solution was obtained for scattering from thin dielectric disks by approximating the currents induced inside the disk with the currents which would exist inside a dielectric slab of the same thickness, orientation and dielectric properties. This approximation reduces to an electrostatic approximation when the disk thickness, T, is small compared to the wavelength of the incident radiation and the approximation yields a conventional physical optics solution when the dimension, A, characteristic of the geometrical cross section of the disk (e.g., the diameter of a circular disk) is large compared to wavelength. When the ratio A/T is sufficiently large the disk will always be in one or the other of these regimes (T lambda or kA1. Consequently, when A/T is large this solution provides a conventional approximation for the scattered fields which can be applied at all frequencies. As a check on this conclusion, a comparison was made between the theoretical and measured radar cross section of thin dielectric disks. Agreement was found for thin disks with both large and small values of kA.

  1. (Thin films under chemical stress)

    SciTech Connect

    Not Available

    1990-01-01

    As stated above the purpose of this research is to enable workers in a variety of fields to understand the chemical and physical changes which take place when thin films (primarily organic films) are placed under chemical stress. This stress may occur because the film is being swelled by penetrant entrained in solvent, because interfacial reactions are occurring at one or more boundaries within the film structure, or because some component of the film is responding to an external stimulus (e.g. pH, temperature, electric field, or radiation). These questions are important within the context of our long-term goal of understanding the behavior of composite structures, composed of thin organic polymer films interspersed with Langmuir-Blodgett (LB) and self-assembled monolayers, which might have unique functional properties. In the past year we have concentrated on the following objectives: (1) understanding how the two possible diffusion mechanisms contribute to the swelling of thin films of organic polymers place in solution, (2) identifying systems which are appropriate polymer media for the construction of composite membranes for use in aqueous environments, and (3) understanding the self-assembly process for long chain fatty acids at model surfaces. Progress in meeting each of these objectives will be described in this report. 4 figs.

  2. Thin Watts-Strogatz networks

    NASA Astrophysics Data System (ADS)

    de Moura, Alessandro P. S.

    2006-01-01

    A modified version of the Watts-Strogatz (WS) network model is proposed, in which the number of shortcuts scales with the network size N as Nα , with α<1 . In these networks, the ratio of the number of shortcuts to the network size approaches zero as N→∞ , whereas in the original WS model, this ratio is constant. We call such networks “thin Watts-Strogatz networks.” We show that even though the fraction of shortcuts becomes vanishingly small for large networks, they still cause a kind of small-world effect, in the sense that the length L of the network increases sublinearly with the size. We develop a mean-field theory for these networks, which predicts that the length scales as N1-αlnN for large N . We also study how a search using only local information works in thin WS networks. We find that the search performance is enhanced compared to the regular network, and we predict that the search time τ scales as N1-α/2 . These theoretical results are tested using numerical simulations. We comment on the possible relevance of thin WS networks for the design of high-performance low-cost communication networks.

  3. Thinning increases climatic resilience of red pine

    USGS Publications Warehouse

    Magruder, Matthew; Chhin, Sophan; Palik, Brian; Bradford, John B.

    2013-01-01

    Forest management techniques such as intermediate stand-tending practices (e.g., thinning) can promote climatic resiliency in forest stands by moderating tree competition. Residual trees gain increased access to environmental resources (i.e., soil moisture, light), which in turn has the potential to buffer trees from stressful climatic conditions. The influences of climate (temperature and precipitation) and forest management (thinning method and intensity) on the productivity of red pine (Pinus resinosa Ait.) in Michigan were examined to assess whether repeated thinning treatments were able to increase climatic resiliency (i.e., maintaining productivity and reduced sensitivity to climatic stress). The cumulative productivity of each thinning treatment was determined, and it was found that thinning from below to a residual basal area of 14 m2·ha−1 produced the largest average tree size but also the second lowest overall biomass per acre. On the other hand, the uncut control and the thinning from above to a residual basal area of 28 m2·ha−1 produced the smallest average tree size but also the greatest overall biomass per acre. Dendrochronological methods were used to quantify sensitivity of annual radial growth to monthly and seasonal climatic factors for each thinning treatment type. Climatic sensitivity was influenced by thinning method (i.e., thinning from below decreased sensitivity to climatic stress more than thinning from above) and by thinning intensity (i.e., more intense thinning led to a lower climatic sensitivity). Overall, thinning from below to a residual basal area of 21 m2·ha−1 represented a potentially beneficial compromise to maximize tree size, biomass per acre, and reduced sensitivity to climatic stress, and, thus, the highest level of climatic resilience.

  4. Computational modeling of thin ceramic tiles backed by thin substrates

    SciTech Connect

    Walker, J.D.; Anderson, C.E. Jr.; Cox, P.A.

    1995-12-31

    Building on the work of Wilkins, Eulerian hydrocode calculations were performed with ceramic models to examine the behavior of thin ceramic tiles backed by a thin substrate. In order to match ballistic limit data it was necessary to include a pressure dependent flow stress for failed ceramic. Reasonable agreement is found between the modified model and ballistic limit data for a simulated armor piercing round impacting an AD-85 alumina/6061T6 aluminum laminate. Based upon this success, the modified model was used to examine the performance of a SiC/6061T6 aluminum laminate when impacted by an M80 ball round (7.62 mm) at muzzle velocity. The projectile undergoes large deformation, as does the aluminum backing sheet. The computational results indicate, for the M80 projectile impacting at muzzle velocity, that the ballistic limit thickness for the SiC/aluminum laminate should weigh 10% less than the ballistic limit thickness for steel. The talk will include a video tape of calculations.

  5. New thin materials for electronics.

    SciTech Connect

    Schwartzberg, Adam

    2012-02-01

    The work described in this report is from an Early Career LDRD to develop and investigate novel thin film organic conductors with drastically improved electronic properties over the current state of the art. In collaboration with the Molecular Foundry at Lawrence Berkeley National Laboratory a Langmuir-Blodgett trough (LB) was built from scavenged parts and added to a scanning Raman microscope at LBNL. First order thin peptoid film samples were fabricated for testing Raman and photoluminescence imagining techniques. Tests showed that a single peptoid sheet can be successfully imaged using confocal Raman spectroscopy and a peptoid sheet can be successfully imaged using near-field photoluminescence at a resolution less than 70 nm. These results have helped position Sandia for advances in this area of MOF film creation. In collaboration with the Molecular Foundry at Lawrence Berkeley National Laboratory, a Langmuir-Blodgett trough (LB) was built and added to a scanning Raman microscope at LBNL. Thin peptoid film samples were fabricated for testing Raman and photoluminescence imagining techniques. Tests showed that a single peptoid sheet can be successfully imaged using confocal Raman spectroscopy, and a peptoid sheet can be successfully imaged using near-field photoluminescence at a resolution less than 70 nm. These results have positioned Sandia for advance in this area of MOF film creation. The interactions with LBNL also led to award of two user projects at the Molecular Foundry at LBNL led by current Sandia staff and the appointment of a current Sandia staff to the Molecular Foundry User Executive Committee.

  6. Thin film buried anode battery

    DOEpatents

    Lee, Se-Hee; Tracy, C. Edwin; Liu, Ping

    2009-12-15

    A reverse configuration, lithium thin film battery (300) having a buried lithium anode layer (305) and process for making the same. The present invention is formed from a precursor composite structure (200) made by depositing electrolyte layer (204) onto substrate (201), followed by sequential depositions of cathode layer (203) and current collector (202) on the electrolyte layer. The precursor is subjected to an activation step, wherein a buried lithium anode layer (305) is formed via electroplating a lithium anode layer at the interface of substrate (201) and electrolyte film (204). The electroplating is accomplished by applying a current between anode current collector (201) and cathode current collector (202).

  7. Thin film solar energy collector

    DOEpatents

    Aykan, Kamran; Farrauto, Robert J.; Jefferson, Clinton F.; Lanam, Richard D.

    1983-11-22

    A multi-layer solar energy collector of improved stability comprising: (1) a substrate of quartz, silicate glass, stainless steel or aluminum-containing ferritic alloy; (2) a solar absorptive layer comprising silver, copper oxide, rhodium/rhodium oxide and 0-15% by weight of platinum; (3) an interlayer comprising silver or silver/platinum; and (4) an optional external anti-reflective coating, plus a method for preparing a thermally stable multi-layered solar collector, in which the absorptive layer is undercoated with a thin film of silver or silver/platinum to obtain an improved conductor-dielectric tandem.

  8. Thin film based plasmon nanorulers

    NASA Astrophysics Data System (ADS)

    Taylor, Alexander D.; Lu, Chang; Geyer, Scott; Carroll, D. L.

    2016-07-01

    In this work, isolated metal nanoparticles are supported on a dielectric thin film that is placed on a conducting plane. The optical scattering characteristics of these metal nanoparticles are directly correlated with the localized surface plasmon states of the nanoparticle—image particle dimer, formed in the conducting plane below. Quantification of plasmon resonance shifts can be directly correlated with the application of the plasmon nanoruler equation. This simple geometry shows that direct optical techniques can be used to resolve thickness variations in dielectrics of only a few nanometers.

  9. Advanced Thin Ionization Calorimeter (ATIC)

    NASA Technical Reports Server (NTRS)

    Wefel, John P.

    1998-01-01

    This is the final report for NASA grant NAGW-4577, "Advanced Thin Ionization Calorimeter (ATIC)". This grant covered a joint project between LSU and the University of Maryland for a Concept Study of a new type of fully active calorimeter to be used to measure the energy spectra of very high energy cosmic rays, particularly Hydrogen and Helium, to beyond 1014 eV. This very high energy region has been studied with emulsion chamber techniques, but never investigated with electronic calorimeters. Technology had advanced to the point that a fully active calorimeter based upon Bismuth Germanate (BGO) scintillating crystals appeared feasible for balloon flight (and eventually space) experiments.

  10. Improved Thin, Flexible Heat Pipes

    NASA Technical Reports Server (NTRS)

    Rosenfeld, John H.; Gernert, Nelson J.; Sarraf, David B.; Wollen, Peter J.; Surina, Frank C.; Fale, John E.

    2004-01-01

    Flexible heat pipes of an improved type are fabricated as layers of different materials laminated together into vacuum- tight sheets or tapes. In comparison with prior flexible heat pipes, these flexible heat pipes are less susceptible to leakage. Other advantages of these flexible heat pipes, relative to prior flexible heat pipes, include high reliability and greater ease and lower cost of fabrication. Because these heat pipes are very thin, they are highly flexible. When coated on outside surfaces with adhesives, these flexible heat pipes can be applied, like common adhesive tapes, to the surfaces of heat sinks and objects to be cooled, even if those surfaces are curved.

  11. Characteristics Of Vacuum Deposited Sucrose Thin Films

    NASA Astrophysics Data System (ADS)

    Ungureanu, F.; Predoi, D.; Ghita, R. V.; Vatasescu-Balcan, R. A.; Costache, M.

    Thin films of sucrose (C12H22O11) were deposited on thin cut glass substrates by thermal evaporation technique (p ~ 10-5 torr). The surface morphology was putted into evidence by FT-IR and SEM analysis. The experimental results confirm a uniform deposition of an adherent sucrose layer. The biological tests (e.g., cell morphology and cell viability evaluated by measuring mitochondrial dehydrogenise activity with MTT assay) confirm the properties of sucrose thin films as bioactive material. The human fetal osteoblast system grown on thin sucrose film was used for the determination of cell proliferation, cell viability and cell morphology studies.

  12. Capillary Thinning of Particle-laden Drops

    NASA Astrophysics Data System (ADS)

    Wagoner, Brayden; Thete, Sumeet; Jahns, Matt; Doshi, Pankaj; Basaran, Osman

    2015-11-01

    Drop formation is central in many applications such as ink-jet printing, microfluidic devices, and atomization. During drop formation, a thinning filament is created between the about-to-form drop and the fluid hanging from the nozzle. Therefore, the physics of capillary thinning of filaments is key to understanding drop formation and has been thoroughly studied for pure Newtonian fluids. The thinning dynamics is, however, altered completely when the fluid contains particles, the physics of which is not well understood. In this work, we explore the impact of solid particles on filament thinning and drop formation by using a combination of experiments and numerical simulations.

  13. Beryllium thin films for resistor applications

    NASA Technical Reports Server (NTRS)

    Fiet, O.

    1972-01-01

    Beryllium thin films have a protective oxidation resistant property at high temperature and high recrystallization temperature. However, the experimental film has very low temperature coefficient of resistance.

  14. Analysis of Hard Thin Film Coating

    NASA Technical Reports Server (NTRS)

    Shen, Dashen

    1998-01-01

    MSFC is interested in developing hard thin film coating for bearings. The wearing of the bearing is an important problem for space flight engine. Hard thin film coating can drastically improve the surface of the bearing and improve the wear-endurance of the bearing. However, many fundamental problems in surface physics, plasma deposition, etc, need further research. The approach is using electron cyclotron resonance chemical vapor deposition (ECRCVD) to deposit hard thin film an stainless steel bearing. The thin films in consideration include SiC, SiN and other materials. An ECRCVD deposition system is being assembled at MSFC.

  15. Analysis of Hard Thin Film Coating

    NASA Technical Reports Server (NTRS)

    Shen, Dashen

    1998-01-01

    Marshall Space Flight Center (MSFC) is interested in developing hard thin film coating for bearings. The wearing of the bearing is an important problem for space flight engine. Hard thin film coating can drastically improve the surface of the bearing and improve the wear-endurance of the bearing. However, many fundamental problems in surface physics, plasma deposition, etc, need further research. The approach is using Electron Cyclotron Resonance Chemical Vapor Deposition (ECRCVD) to deposit hard thin film on stainless steel bearing. The thin films in consideration include SiC, SiN and other materials. An ECRCVD deposition system is being assembled at MSFC.

  16. Thin film solar cell module

    SciTech Connect

    Gay, R.R.

    1987-01-20

    A thin film solar cell module is described comprising a first solar cell panel containing an array of solar cells consisting of a TFS semiconductor sandwiched between a transparent conductive zinc oxide layer and a transparent conductive layer selected from the group consisting of tin oxide, indium tin oxide, and zinc oxide deposited upon a transparent superstrate, and a second solar cell panel containing an array of solar cells consisting of a CIS semiconductor layer sandwiched between a zinc oxide semiconductor layer and a conductive metal layer deposited upon an insulating substrate. The zinc oxide semiconductor layer contains a first relatively thin layer of high resistivity zinc oxide adjacent the CIS semiconductor and a second relatively thick layer of low resistivity zinc oxide overlying the high resistivity zinc oxide layer. The transparent conductive zinc oxide layer of the first panel faces the low resistivity zinc oxide layer of the second panel, the first and second panels being positioned optically in series and separated by a transparent insulating layer.

  17. Superconducting UBe 13 thin films

    NASA Astrophysics Data System (ADS)

    Quateman, J. H.; Tedrow, P. M.

    1985-12-01

    Of the known heavy fermion superconductors only UBe 13 can have a low resistivity ratio and still go superconducting. In addition, it is a line compound with a melting temperature of nearly twice that of the constituents. These facts make UBe 13 a promising choice for fabrication in thin film form. We have successfully made 2000 Å UBe 13 films by coevaporation of uranium and beryllium on 700°C substrates which were then heated in situ to 1100°C. These films were polycrystalline as shown by X-ray diffraction and have Tc's of 0.85 K, that of the bulk. The resistivity rise at approximately 2 K and the strong negative magnetoresistance were also of the same magnitude as that of the bulk, as were both the perpendicular and parallel critical fields. Thin films of UBe 13 will make more accessible tunneling and proximity effect experiments which can help elucidate the nature of the superconductivity of this compound.

  18. Plasmonics in atomically thin materials.

    PubMed

    García de Abajo, F Javier; Manjavacas, Alejandro

    2015-01-01

    The observation and electrical manipulation of infrared surface plasmons in graphene have triggered a search for similar photonic capabilities in other atomically thin materials that enable electrical modulation of light at visible and near-infrared frequencies, as well as strong interaction with optical quantum emitters. Here, we present a simple analytical description of the optical response of such kinds of structures, which we exploit to investigate their application to light modulation and quantum optics. Specifically, we show that plasmons in one-atom-thick noble-metal layers can be used both to produce complete tunable optical absorption and to reach the strong-coupling regime in the interaction with neighboring quantum emitters. Our methods are applicable to any plasmon-supporting thin materials, and in particular, we provide parameters that allow us to readily calculate the response of silver, gold, and graphene islands. Besides their interest for nanoscale electro-optics, the present study emphasizes the great potential of these structures for the design of quantum nanophotonics devices. PMID:25774774

  19. Thin film of biocompatible polysaccharides

    NASA Astrophysics Data System (ADS)

    Richert, Ludovic; Lavalle, Philippe; Schaaf, Pierre; Voegel, Jean-Claude; Picart, Catherine

    2003-03-01

    The layer-by-layer deposition method proposed by Decher et al. (1991) is a very simple and versatile method used to build thin films. These films are of interest for bioengineering because of their unique properties and of the possible insertion of bioactive molecules. We present here the peculiar properties of a new kind of film formed with natural biopolymers, namely hyaluronan (HA)and chitosan (CHI). The films may be used as biomimetic substrates to control bacterial and cell adhesion. These polysaccharides are of particular interest because they are biodegradable, non toxic, and can be found in various tissues. Hyaluronan is also a natural ligand for a numerous type of cells through the CD44 receptor. Chitosan has already largely been used for its biological and anti-microbial properties. (CHI/HA) films were built in acidic pH at different ionic strength. The buildup was followed in situ by optical waveguide lightmode spectroscopy (OWLS), quartz crystal microbalance, streaming potential measurements and atomic force microscopy. The kinetics of adsorption and desorption of the polyelectrolytes depended on the ionic strength. Small islands were initially present on the surface which grew by mutual coalescence until becoming a flat film. The films were around 200 nm in thickness. These results suggest that different types of thin films constituted of polysaccharides can be built on any type of surface. These films are currently investigated toward their cell adhesion and bacterial adhesion properties.

  20. Thin films of mixed metal compounds

    DOEpatents

    Mickelsen, Reid A.; Chen, Wen S.

    1985-01-01

    A compositionally uniform thin film of a mixed metal compound is formed by simultaneously evaporating a first metal compound and a second metal compound from independent sources. The mean free path between the vapor particles is reduced by a gas and the mixed vapors are deposited uniformly. The invention finds particular utility in forming thin film heterojunction solar cells.

  1. Recent advances in thin-layer chromatography

    SciTech Connect

    Dallas, F.A.A.; Read, H.; Ruane, R.J.; Wilson, I.D.

    1988-01-01

    This book is a collection of proceedings from the 1987 Chromatographic Society International Symposium on Thin-Layer Chromatography in Brighton. The book is divided into four sections: Instrumentation, Radio-Thin-Layer Chromatography, Sorbents and Modifiers, and Applications. References date from the 1970s to the mid-1980s. Compounds and subject indexes are included.

  2. Thin CVD Coating Protects Titanium Aluminide Alloys

    NASA Technical Reports Server (NTRS)

    Clark, Ronald; Wallace, Terryl; Cunnington, George; Robinson, John

    1994-01-01

    Feasibility of using very thin CVD coatings to provide both protection against oxidation and surfaces of low catalytic activity for thin metallic heat-shield materials demonstrated. Use of aluminum in compositions increases emittances of coatings and reduces transport of oxygen through coatings to substrates. Coatings light in weight and applied to foil-gauge materials with minimum weight penalties.

  3. Thin Silicon MEMS Contact-Stress Sensor

    SciTech Connect

    Kotovksy, J; Tooker, A; Horsley, D

    2010-05-28

    This thin, MEMS contact-stress sensor continuously and accurately measures time-varying, solid interface loads over tens of thousands of load cycles. The contact-stress sensor is extremely thin (150 {mu}m) and has a linear output with an accuracy of {+-} 1.5% FSO.

  4. Thin-Film Nanocapacitor and Its Characterization

    ERIC Educational Resources Information Center

    Hunter, David N.; Pickering, Shawn L.; Jia, Dongdong

    2007-01-01

    An undergraduate thin-film nanotechnology laboratory was designed. Nanocapacitors were fabricated on silicon substrates by sputter deposition. A mask was designed to form the shape of the capacitor and its electrodes. Thin metal layers of Au with a 80 nm thickness were deposited and used as two infinitely large parallel plates for a capacitor.…

  5. Collapsing thin shells with rotation

    NASA Astrophysics Data System (ADS)

    Delsate, Térence; Rocha, Jorge V.; Santarelli, Raphael

    2014-06-01

    We construct exact solutions describing the motion of rotating thin shells in a fully backreacted five-dimensional rotating black hole spacetime. The radial equation of motion follows from the Darmois-Israel junction conditions, where both interior and exterior geometries are taken to be equal angular momenta Myers-Perry solutions. We show that rotation generates anisotropic pressures and momentum along the shell. Gravitational collapse scenarios including rotation are analyzed and a new class of stationary solutions is introduced. Energy conditions for the anisotropic matter shell are briefly discussed. We find that the weak energy condition is not violated for the collapse scenario where the shell starts at rest from infinity, nor for the new class of stationary solutions in anti-de Sitter. We further prove that the cosmic censorship conjecture is always satisfied in our setup.

  6. Thin-film optical shutter

    NASA Astrophysics Data System (ADS)

    Matlow, S. L.

    1981-02-01

    The ideal solution to the excessive solar gain problem is an optical shutter, a device which switches from being highly transmissive to solar radiation to being highly reflective to solar radiation when a critical temperature is reached in the enclosure. The switching occurs because one or more materials in the device undergo a phase transition at the critical temperature. A specific embodiment of macroconjugated macromolecules, the poly (p-phenylene)'s, was chosen as the one most likely to meet all of the requirements of the thin film optical shutter project (TFOS). The reason for this choice is explored. In order to be able to make meaningful calculations of the thermodynamic and optical properties of the poly (p-phenylene)'s a quantum mechanical method, the equilibrium bond length (EBL) theory, was developed. Some results of EBL theory are included.

  7. Thin film bioreactors in space

    NASA Technical Reports Server (NTRS)

    Hughes-Fulford, M.; Scheld, H. W.

    1989-01-01

    Studies from the Skylab, SL-3 and D-1 missions have demonstrated that biological organisms grown in microgravity have changes in basic cellular functions such as DNA, mRNA and protein synthesis, cytoskeleton synthesis, glucose utilization, and cellular differentiation. Since microgravity could affect prokaryotic and eukaryotic cells at a subcellular and molecular level, space offers an opportunity to learn more about basic biological systems with one inmportant variable removed. The thin film bioreactor will facilitate the handling of fluids in microgravity, under constant temperature and will allow multiple samples of cells to be grown with variable conditions. Studies on cell cultures grown in microgravity would make it possible to identify and quantify changes in basic biological function in microgravity which are needed to develop new applications of orbital research and future biotechnology.

  8. Wrinkle motifs in thin films

    PubMed Central

    Budrikis, Zoe; Sellerio, Alessandro L.; Bertalan, Zsolt; Zapperi, Stefano

    2015-01-01

    On length scales from nanometres to metres, partial adhesion of thin films with substrates generates a fascinating variety of patterns, such as ‘telephone cord’ buckles, wrinkles, and labyrinth domains. Although these patterns are part of everyday experience and are important in industry, they are not completely understood. Here, we report simulation studies of a previously-overlooked phenomenon in which pairs of wrinkles form avoiding pairs, focusing on the case of graphene over patterned substrates. By nucleating and growing wrinkles in a controlled way, we characterize how their morphology is determined by stress fields in the sheet and friction with the substrate. Our simulations uncover the generic behaviour of avoiding wrinkle pairs that should be valid at all scales. PMID:25758174

  9. BDS thin film damage competition

    SciTech Connect

    Stolz, C J; Thomas, M D; Griffin, A J

    2008-10-24

    A laser damage competition was held at the 2008 Boulder Damage Symposium in order to determine the current status of thin film laser resistance within the private, academic, and government sectors. This damage competition allows a direct comparison of the current state-of-the-art of high laser resistance coatings since they are all tested using the same damage test setup and the same protocol. A normal incidence high reflector multilayer coating was selected at a wavelength of 1064 nm. The substrates were provided by the submitters. A double blind test assured sample and submitter anonymity so only a summary of the results are presented here. In addition to the laser resistance results, details of deposition processes, coating materials, and layer count will also be shared.

  10. Preparation and Characterization of PZT Thin Films

    SciTech Connect

    Bose, A.; Sreemany, M.; Bhattacharyya, D. K.; Sen, Suchitra; Halder, S. K.

    2008-07-29

    In analogy with Piezoelectric Wafer Active Sensors (PWAS), Lead Zirconate Titanate (PZT) thin films also seem to be promising for Structural Health Monitoring (SHM) due to a number of reasons. Firstly, PZT thin films with well oriented domains show enhanced piezoelectric response. Secondly, PWAS requires comparatively large voltage leading to a demand for thin PZT films (<< {mu}m in thickness) for low voltage operation at {<=}10 V. This work focuses on two different aspects: (a) growing oriented PZT thin films in ferroelectric perovskite phase in the range of (80-150) nm thickness on epitaxial Si/Pt without a seed layer and (b) synthesizing perovskite phase in PZT thin films on Corning glass 1737 using a seed layer of TiO{sub x} (TiO{sub x} thickness ranging between 30 nm to 500 nm)

  11. Zinc oxide thin film acoustic sensor

    SciTech Connect

    Mohammed, Ali Jasim; Salih, Wafaa Mahdi; Hassan, Marwa Abdul Muhsien; Nusseif, Asmaa Deiaa; Kadhum, Haider Abdullah; Mansour, Hazim Louis

    2013-12-16

    This paper reports the implementation of (750 nm) thickness of Zinc Oxide (ZnO) thin film for the piezoelectric pressure sensors. The film was prepared and deposited employing the spray pyrolysis technique. XRD results show that the growth preferred orientation is the (002) plane. A polycrystalline thin film (close to mono crystallite like) was obtained. Depending on the Scanning Electron Microscopy photogram, the film homogeneity and thickness were shown. The resonance frequency measured (about 19 kHz) and the damping coefficient was calculated and its value was found to be about (2.5538), the thin film be haves as homogeneous for under and over damped. The thin film pressure sensing was approximately exponentially related with frequency, the thin film was observed to has a good response for mechanical stresses also it is a good material for the piezoelectric properties.

  12. New devices using ferroelectric thin films

    SciTech Connect

    Land, C.E.; Butler, M.A.; Martin, S.J.

    1989-01-01

    Recent developments in the fabrication technologies of ferroelectric thin films in general and of PZT (lead zirconate titanate) and PLZT (lead lanthanum zirconate titanate) thin films in particular have suggested the feasibility of several new devices. Integrated optical devices for information processing and high-speed switching, high-density optical information processing and storage devices and spatial light modulators are some of the applications currently being investigated for these films. Ongoing studies of the longitudinal electrooptic effects and the photosensitivities of PZT and PLZT thin films have established the feasibility of erasable/rewritable optical memories with fast switching and potentially long lifetimes compared to current magneto-optic thin film devices. Some properties of PZT thin films and of new devices based on those properties are described in this paper. 15 refs., 5 figs., 1 tab.

  13. A monolithic thin film electrochromic window

    SciTech Connect

    Goldner, R.B.; Arntz, F.O.; Berera, G.; Haas, T.E.; Wong, K.K. . Electro-Optics Technology Center); Wei, G. ); Yu, P.C. )

    1991-01-01

    Three closely related thin film solid state ionic devices that are potentially important for applications are: electrochromic smart windows, high energy density thin film rechargeable batteries, and thin film electrochemical sensors. Each usually has at least on mixed ion/electron conductor, an electron-blocking ion conductor, and an ion-blocking electron conductor, and many of the technical issues associated with thin film solid state ionics are common to all three devices. Since the electrochromic window has the added technical requirement of electrically-controlled optical modulation, (over the solar spectrum), and since research at the authors' institution has focused primarily on the window structure, this paper will address the electrochromic window, and particularly a monolithic variable reflectivity electrochromic window, as an illustrative example of some of the challenges and opportunities that are confronting the thin film solid state ionics community. 33 refs.

  14. A monolithic thin film electrochromic window

    SciTech Connect

    Goldner, R.B.; Arntz, F.O.; Berera, G.; Haas, T.E.; Wong, K.K.; Wei, G.; Yu, P.C.

    1991-12-31

    Three closely related thin film solid state ionic devices that are potentially important for applications are: electrochromic smart windows, high energy density thin film rechargeable batteries, and thin film electrochemical sensors. Each usually has at least on mixed ion/electron conductor, an electron-blocking ion conductor, and an ion-blocking electron conductor, and many of the technical issues associated with thin film solid state ionics are common to all three devices. Since the electrochromic window has the added technical requirement of electrically-controlled optical modulation, (over the solar spectrum), and since research at the authors` institution has focused primarily on the window structure, this paper will address the electrochromic window, and particularly a monolithic variable reflectivity electrochromic window, as an illustrative example of some of the challenges and opportunities that are confronting the thin film solid state ionics community. 33 refs.

  15. Zinc oxide thin film acoustic sensor

    NASA Astrophysics Data System (ADS)

    Mohammed, Ali Jasim; Salih, Wafaa Mahdi; Hassan, Marwa Abdul Muhsien; Mansour, Hazim Louis; Nusseif, Asmaa Deiaa; Kadhum, Haider Abdullah

    2013-12-01

    This paper reports the implementation of (750 nm) thickness of Zinc Oxide (ZnO) thin film for the piezoelectric pressure sensors. The film was prepared and deposited employing the spray pyrolysis technique. XRD results show that the growth preferred orientation is the (002) plane. A polycrystalline thin film (close to mono crystallite like) was obtained. Depending on the Scanning Electron Microscopy photogram, the film homogeneity and thickness were shown. The resonance frequency measured (about 19 kHz) and the damping coefficient was calculated and its value was found to be about (2.5538), the thin film be haves as homogeneous for under and over damped. The thin film pressure sensing was approximately exponentially related with frequency, the thin film was observed to has a good response for mechanical stresses also it is a good material for the piezoelectric properties.

  16. Surface defects on thin cryosections.

    PubMed

    Frederik, P M; Busing, W M; Persson, A

    1984-01-01

    The electron microscopic observation of thin cryosections is frequently impaired by the occurrence of surface defects. To investigate the possible causes of these surface defects the structure of cryosections ( CTEM ) from frozen biological material was correlated with the structure of the block-face (SEM) from which the sections were obtained. Both sections and block-face showed steps with a periodicity larger than 0.5 micron. Upon dry sectioning of hard plastic comparable features were observed in the section ( CTEM /SEM) and block-face (SEM). Thin cryosections cut below 143 K were found to be smooth apart from defects introduced by imperfections of the knife. In addition to "long" wave length distortions, a periodical distortion smaller than 120 nm can be observed in cryosections from biological material. At a given temperature the frequency is related to the sectioning speed. At all sectioning temperatures studied, distortions of this high frequency/short wave length type have been observed although they were less conspicuous in thinner sections. The surface defects observed in cryosections from biological material resemble the defects found after metal cutting and chip-formation. Shear forces seem to be the main causes for the observed periodic deformations on both cryosections as well as on sections from metals and plastics. This may imply that material is collected and periodically shedded from a dead zone around the knife edge. In metal cutting such a dead zone can have the form of a built-up-edge on top of the knife or as a small overhang in front of the knife edge. PMID:6377477

  17. Longwall mining of thin seams

    SciTech Connect

    Curth, E A

    1981-01-01

    Thin seam operations pose a challenge to the ingenuity of mining engineers to overcome the factor of human inconvenience in the restricted environment and associated high cost production. Surprisingly, low seam longwalls in the Federal Republic of Germany in an average thickness of 35 in. and dipping less than 18/sup 0/ come close to achieving the average production rate of all German longwall operations. They are all plow faces, and a consistent production of 3300 tons per day and a productivity of 40 tons per man shift are reported from one of the thin seam longwalls. These results were attained by reliable high-capacity equipment and roof support by shields that can be collapsed to as low as 22 inches. Maximum mining height for plow operated faces lies at 31.5 inches. Technology for mechanized mining of flat lying coalbeds less than 31.5 inches in thickness without rock cutting is not available, and firmness of coal, undulation of the strata, coalbed thickness variation, and the necessity of cutting rock, particularly through faults, set limits to plow application. The in-web shearer can be used in firm coal to a minimum mining height of 40 inches, and a daily production of 1650 to 2200 tons is reported from a longwall in the Saar district of Germany equipped with such a shearer and shields. Numerous in-web shearers are employed in the United Kingdom; reports as to their success are contradictory. Also, experience in the United States, though limited, has been negative. The steady increase in output from single drum shearer faces in Pennsylvania is a remarkable achievement, and occasional record breaking peaks in production indicate the potential of such mining. Technology development for the future is discussed.

  18. Mutation-Specific Effects on Thin Filament Length in Thin Filament Myopathy

    PubMed Central

    de Winter, Josine M.; Joureau, Barbara; Lee, Eun-Jeong; Kiss, Balázs; Yuen, Michaela; Gupta, Vandana A.; Pappas, Christopher T.; Gregorio, Carol C.; Stienen, Ger J. M.; Edvardson, Simon; Wallgren-Pettersson, Carina; Lehtokari, Vilma-Lotta; Pelin, Katarina; Malfatti, Edoardo; Romero, Norma B.; van Engelen, Baziel G.; Voermans, Nicol C.; Donkervoort, Sandra; Bönnemann, C. G.; Clarke, Nigel F.; Beggs, Alan H.; Granzier, Henk; Ottenheijm, Coen A. C.

    2016-01-01

    Objective Thin filament myopathies are among the most common nondystrophic congenital muscular disorders, and are caused by mutations in genes encoding proteins that are associated with the skeletal muscle thin filament. Mechanisms underlying muscle weakness are poorly understood, but might involve the length of the thin filament, an important determinant of force generation. Methods We investigated the sarcomere length-dependence of force, a functional assay that provides insights into the contractile strength of muscle fibers as well as the length of the thin filaments, in muscle fibers from 51 patients with thin filament myopathy caused by mutations in NEB, ACTA1, TPM2, TPM3, TNNT1, KBTBD13, KLHL40, and KLHL41. Results Lower force generation was observed in muscle fibers from patients of all genotypes. In a subset of patients who harbor mutations in NEB and ACTA1, the lower force was associated with downward shifted force–sarcomere length relations, indicative of shorter thin filaments. Confocal microscopy confirmed shorter thin filaments in muscle fibers of these patients. A conditional Neb knockout mouse model, which recapitulates thin filament myopathy, revealed a compensatory mechanism; the lower force generation that was associated with shorter thin filaments was compensated for by increasing the number of sarcomeres in series. This allowed muscle fibers to operate at a shorter sarcomere length and maintain optimal thin–thick filament overlap. Interpretation These findings might provide a novel direction for the development of therapeutic strategies for thin filament myopathy patients with shortened thin filament lengths. PMID:27074222

  19. Fillability of Thin-Wall Steel Castings

    SciTech Connect

    Robert C. Voigt; Joseph Bertoletti; Andrew Kaley; Sandi Ricotta; Travis Sunday

    2002-07-30

    The use of steel components is being challenged by lighter nonferrous or cast iron components. The development of techniques for enhancing and ensuring the filability of thin-wall mold cavities is most critical for thinner wall cast steel production. The purpose of this research was to develop thin-wall casting techniques that can be used to reliably produce thin-wall castings from traditional gravity poured sand casting processes. The focus of the research was to enhance the filling behavior to prevent misrunds. Experiments were conducted to investigate the influence of various foundry variables on the filling of thin section steel castings. These variables include casting design, heat transfer, gating design, and metal fluidity. Wall thickness and pouring temperature have the greatest effect on casting fill. As wall thickness increases the volume to surface area of the casting increases, which increases the solidification time, allowing the metal to flow further in thicker sect ions. Pouring time is another significant variable affecting casting fill. Increases or decreases of 20% in the pouring time were found to have a significant effect on the filling of thin-wall production castings. Gating variables, including venting, pouring head height, and mold tilting also significantly affected thin-wall casting fill. Filters offer less turbulent, steadier flow, which is appropriate for thicker castings, but they do not enhance thin-wall casting fill.

  20. Accelerated longitudinal cortical thinning in adolescence.

    PubMed

    Zhou, Dongming; Lebel, Catherine; Treit, Sarah; Evans, Alan; Beaulieu, Christian

    2015-01-01

    It remains unclear if changes of the cerebral cortex occur gradually from childhood to adulthood, or if adolescence marks a differential period of cortical development. In the current study of 90 healthy volunteers aged 5-32years (48 females, 85 right handed) with 180 scans (2 scans for each participant with ~4year gaps), thinning of overall mean thickness and across the four major cortical lobes bilaterally was observed across this full age span. However, the thinning rate, calculated as Δcortical thickness/Δage (mm/year) between scans of each participant, revealed an accelerated cortical thinning during adolescence, which was preceded by less thinning in childhood and followed by decelerated thinning in young adulthood. Males and females showed similarly faster thinning rates during adolescence relative to young adults. The underlying basis and role of accelerated cortical thinning during adolescence for cognition, behaviour and disorders that appear at such a stage of development remains to be determined in future work. PMID:25312772

  1. Weld Repair of Thin Aluminum Sheet

    NASA Technical Reports Server (NTRS)

    Beuyukian, C. S.; Mitchell, M. J.

    1986-01-01

    Weld repairing of thin aluminum sheets now possible, using niobium shield and copper heat sinks. Refractory niobium shield protects aluminum adjacent to hole, while copper heat sinks help conduct heat away from repair site. Technique limits tungsten/inert-gas (TIG) welding bombardment zone to melt area, leaving surrounding areas around weld unaffected. Used successfully to repair aluminum cold plates on Space Shuttle, Commercial applications, especially in sealing fractures, dents, and holes in thin aluminum face sheets or clad brazing sheet in cold plates, heat exchangers, coolers, and Solar panels. While particularly suited to thin aluminum sheet, this process also used in thicker aluminum material to prevent surface damage near weld area.

  2. Progressive bilateral thinning of the parietal bones

    SciTech Connect

    Cederlund, C.G.; Andren, L.; Olivecrona, H.

    1982-03-01

    Observation of a case of progressive bilateral parietal thinning within a period of 14 years induced us to study skull films of 3 636 consecutive patients. Parietal thinning was found in 86 patients (2.37%). It was more common in women, with a sex ratio of 1:1.9. The mean age of the females was 72 years, and that of the males 63 years. Previous skull films of 25 of these patients were available and showed progression in 10. It is concluded that parietal thinning is a slowly progressive disease of middle-aged and old patients and is not an anatomical variant or congenital dysplasia of the dipole.

  3. Surface roughness evolution of nanocomposite thin films

    SciTech Connect

    Turkin, A. A.; Pei, Y. T.; Shaha, K. P.; Chen, C. Q.; Vainshtein, D. I.; Hosson, J. Th. M. de

    2009-01-01

    An analysis of dynamic roughening and smoothening mechanisms of thin films grown with pulsed-dc magnetron sputtering is presented. The roughness evolution has been described by a linear stochastic equation, which contains the second- and fourth-order gradient terms. Dynamic smoothening of the growing interface is explained by ballistic effects resulting from impingements of ions to the growing thin film. These ballistic effects are sensitive to the flux and energy of impinging ions. The predictions of the model are compared with experimental data, and it is concluded that the thin film roughness can be further controlled by adjusting waveform, frequency, and width of dc pulses.

  4. Macro stress mapping on thin film buckling

    SciTech Connect

    Goudeau, P.; Villain, P.; Renault, P.-O.; Tamura, N.; Celestre, R.S.; Padmore, H.A.

    2002-11-06

    Thin films deposited by Physical Vapour Deposition techniques on substrates generally exhibit large residual stresses which may be responsible of thin film buckling in the case of compressive stresses. Since the 80's, a lot of theoretical work has been done to develop mechanical models but only a few experimental work has been done on this subject to support these theoretical approaches and nothing concerning local stress measurement mainly because of the small dimension of the buckling (few 10th mm). This paper deals with the application of micro beam X-ray diffraction available on synchrotron radiation sources for stress mapping analysis of gold thin film buckling.

  5. Ultra-thin multilayer capacitors.

    SciTech Connect

    Renk, Timothy Jerome; Monson, Todd C.

    2009-06-01

    The fabrication of ultra-thin lanthanum-doped lead zirconium titanate (PLZT) multilayer ceramic capacitors (MLCCs) using a high-power pulsed ion beam was studied. The deposition experiments were conducted on the RHEPP-1 facility at Sandia National Laboratories. The goal of this work was to increase the energy density of ceramic capacitors through the formation of a multilayer device with excellent materials properties, dielectric constant, and standoff voltage. For successful device construction, there are a number of challenging requirements including achieving correct stoichiometric and crystallographic composition of the deposited PLZT, as well as the creation of a defect free homogenous film. This report details some success in satisfying these requirements, although 900 C temperatures were necessary for PLZT perovskite phase formation. These temperatures were applied to a previously deposited multi-layer film which was then post-annealed to this temperature. The film exhibited mechanical distress attributable to differences in the coefficient of thermal expansion (CTE) of the various layers. This caused significant defects in the deposited films that led to shorts across devices. A follow-on single layer deposition without post-anneal produced smooth layers with good interface behavior, but without the perovskite phase formation. These issues will need to be addressed in order for ion beam deposited MLCCs to become a viable technology. It is possible that future in-situ heating during deposition may address both the CTE issue, and result in lowered processing temperatures, which in turn could raise the probability of successful MLCC formation.

  6. Thin wetting film lensless imaging

    NASA Astrophysics Data System (ADS)

    Allier, C. P.; Poher, V.; Coutard, J. G.; Hiernard, G.; Dinten, J. M.

    2011-03-01

    Lensless imaging has recently attracted a lot of attention as a compact, easy-to-use method to image or detect biological objects like cells, but failed at detecting micron size objects like bacteria that often do not scatter enough light. In order to detect single bacterium, we have developed a method based on a thin wetting film that produces a micro-lens effect. Compared with previously reported results, a large improvement in signal to noise ratio is obtained due to the presence of a micro-lens on top of each bacterium. In these conditions, standard CMOS sensors are able to detect single bacterium, e.g. E.coli, Bacillus subtilis and Bacillus thuringiensis, with a large signal to noise ratio. This paper presents our sensor optimization to enhance the SNR; improve the detection of sub-micron objects; and increase the imaging FOV, from 4.3 mm2 to 12 mm2 to 24 mm2, which allows the detection of bacteria contained in 0.5μl to 4μl to 10μl, respectively.

  7. De Sitter thin brane model

    NASA Astrophysics Data System (ADS)

    Nishi, Masato

    2016-07-01

    We discuss the large mass hierarchy problem in a braneworld model which represents our acceleratively expanding universe. The Randall-Sundrum (RS) model with one extra warped dimension added to a flat four-dimensional space-time cannot describe our expanding universe. Here, we study instead the de Sitter thin brane model. This is described by the same action as that for the RS model, but the four-dimensional space-time on the branes is dS_4. We study the model for both the cases of positive five-dimensional cosmological constant Λ_5 and a negative one. In the positive Λ_5 case, the four-dimensional large hierarchy necessitates a five-dimensional large hierarchy, and we cannot get a natural explanation. On the other hand, in the negative Λ_5 case, the large hierarchy is naturally realized in the five-dimensional theory in the same manner as in the RS model. Moreover, another large hierarchy between the Hubble parameter and the Planck scale is realized by the O(10^2) hierarchy of the five-dimensional quantities. Finally, we find that the lightest mass of the massive Kaluza-Klein modes and the intervals of the mass spectrum are of order 10^2 GeV, which are the same as in the RS case and do not depend on the value of the Hubble parameter.

  8. Reconnection in thin current sheets

    NASA Astrophysics Data System (ADS)

    Tenerani, Anna; Velli, Marco; Pucci, Fulvia; Rappazzo, A. F.

    2016-05-01

    It has been widely believed that reconnection is the underlying mechanism of many explosive processes observed both in nature and laboratory, but the question of reconnection speed and initial trigger have remained mysterious. How is fast magnetic energy release triggered in high Lundquist (S) and Reynolds (R) number plasmas?It has been shown that a tearing mode instability can grow on an ideal timescale, i.e., independent from the the Lundquist number, once the current sheet thickness becomes thin enough, or rather the inverse aspect ratio a/L reaches a scale a/L~S-1/3. As such, the latter provides a natural, critical threshold for current sheets that can be formed in nature before they disrupt in a few Alfvén time units. Here we discuss the transition to fast reconnection extended to simple viscous and kinetic models and we propose a possible scenario for the transition to explosive reconnection in high-Lundquist number plasmas, that we support with fully nonlinear numerical MHD simulations of a collapsing current sheet.

  9. VUV thin films, chapter 7

    NASA Technical Reports Server (NTRS)

    Zukic, Muamer; Torr, Douglas G.

    1993-01-01

    The application of thin film technology to the vacuum ultraviolet (VUV) wavelength region from 120 nm to 230 nm has not been fully exploited in the past because of absorption effects which complicate the accurate determination of the optical functions of dielectric materials. The problem therefore reduces to that of determining the real and imaginary parts of a complex optical function, namely the frequency dependent refractive index n and extinction coefficient k. We discuss techniques for the inverse retrieval of n and k for dielectric materials at VUV wavelengths from measurements of their reflectance and transmittance. Suitable substrate and film materials are identified for application in the VUV. Such applications include coatings for the fabrication of narrow and broadband filters and beamsplitters. The availability of such devices open the VUV regime to high resolution photometry, interferometry and polarimetry both for space based and laboratory applications. This chapter deals with the optics of absorbing multilayers, the determination of the optical functions for several useful materials, and the design of VUV multilayer stacks as applied to the design of narrow and broadband reflection and transmission filters and beamsplitters. Experimental techniques are discussed briefly, and several examples of the optical functions derived for selected materials are presented.

  10. Accelerating thinning of Kenai Peninsula glaciers, Alaska

    NASA Astrophysics Data System (ADS)

    VanLooy, J.; Forster, R.; Ford, A.

    2006-11-01

    Temperate mountain glaciers are thinning at high rates and significantly contributing to sea level rise. Due to these glaciers' remote locations, remote sensing and digital elevation models (DEMs) are an effective way to calculate their thinning rates and contribution to sea level rise. Comparisons of 1950s United States Geological Survey (USGS) and 2000 Shuttle Radar Topographic Mission (SRTM) DEMs with DEMs produced from Lidar profiles of glacier center-lines indicate thinning rates from the mid-1990s to 1999 (-0.72 +/- 0.13 m y-1) accelerated by a factor of 1.5 as compared with 1950 to mid-1990s (-0.47 +/- 0.01 m y-1) for glaciers on the Harding Icefield. Overall, comparison of USGS and SRTM DEMs indicate the Harding Icefield and Grewingk-Yalik Glacier Complex, Alaska, are thinning -0.61 +/- 0.12 m y-1 from 1950 to 1999.

  11. Thermally tunable ferroelectric thin film photonic crystals.

    SciTech Connect

    Lin, P. T.; Wessels, B. W.; Imre, A.; Ocola, L. E.; Northwestern Univ.

    2008-01-01

    Thermally tunable PhCs are fabricated from ferroelectric thin films. Photonic band structure and temperature dependent diffraction are calculated by FDTD. 50% intensity modulation is demonstrated experimentally. This device has potential in active ultra-compact optical circuits.

  12. Spherical aberration in electrically thin flat lenses.

    PubMed

    Ruphuy, Miguel; Ramahi, Omar M

    2016-08-01

    We analyze the spherical aberration of a new generation of lenses made of flat electrically thin inhomogeneous media. For such lenses, spherical aberration is analyzed quantitatively and qualitatively, and comparison is made to the classical gradient index rod. Both flat thin and thick lenses are made of gradient index materials, but the physical mechanisms and design equations are different. Using full-wave three-dimensional numerical simulation, we evaluate the spherical aberrations using the Maréchal criterion and show that the thin lens gives significantly better performance than the thick lens (rod). Additionally, based on ray tracing formulation, third-order analysis for longitudinal aberration and optical path difference are presented, showing strong overall performance of thin lenses in comparison to classical rod lenses. PMID:27505651

  13. Recent developments in thin film solar cells

    NASA Astrophysics Data System (ADS)

    Dhere, Neelkanth G.

    The present status of the development of thin film solar cells is reviewed, with emphasis on important areas for further research. The following aperture-area efficiencies were measured for thin film modules: a-Si:H, 9.8 percent, 933 sq cm; CuIn(Ga)Se2, 11.1 percent, 938 sq cm; and CdTe, 7.3 percent, 838 sq cm. CuIn(Ga)Se2 cells and modules demonstrated excellent efficiencies and stability. The cost advantage of thin film modules and the higher efficiency and improved stability resulting from multijunctions are shown. Engineering solutions are found to minimize light-induced degradation of a-Si:H solar cells. CdTe cells and modules, and cleaved epitaxial thin film III-V compound cells showed remarkable efficiencies.

  14. Thin film production method and apparatus

    DOEpatents

    Loutfy, Raouf O.; Moravsky, Alexander P.; Hassen, Charles N.

    2010-08-10

    A method for forming a thin film material which comprises depositing solid particles from a flowing suspension or aerosol onto a filter and next adhering the solid particles to a second substrate using an adhesive.

  15. Highly stretchable wrinkled gold thin film wires

    NASA Astrophysics Data System (ADS)

    Kim, Joshua; Park, Sun-Jun; Nguyen, Thao; Chu, Michael; Pegan, Jonathan D.; Khine, Michelle

    2016-02-01

    With the growing prominence of wearable electronic technology, there is a need to improve the mechanical reliability of electronics for more demanding applications. Conductive wires represent a vital component present in all electronics. Unlike traditional planar and rigid electronics, these new wearable electrical components must conform to curvilinear surfaces, stretch with the body, and remain unobtrusive and low profile. In this paper, the piezoresistive response of shrink induced wrinkled gold thin films under strain demonstrates robust conductive performance in excess of 200% strain. Importantly, the wrinkled metallic thin films displayed negligible change in resistance of up to 100% strain. The wrinkled metallic wires exhibited consistent performance after repetitive strain. Importantly, these wrinkled thin films are inexpensive to fabricate and are compatible with roll to roll manufacturing processes. We propose that these wrinkled metal thin film wires are an attractive alternative to conventional wires for wearable applications.

  16. Method for making thin carbon foam electrodes

    DOEpatents

    Pekala, R.W.; Mayer, S.T.; Kaschmitter, J.L.; Morrison, R.L.

    1999-08-03

    A method for fabricating thin, flat carbon electrodes by infiltrating highly porous carbon papers, membranes, felts, metal fibers/powders, or fabrics with an appropriate carbon foam precursor material is disclosed. The infiltrated carbon paper, for example, is then cured to form a gel-saturated carbon paper, which is subsequently dried and pyrolyzed to form a thin sheet of porous carbon. The material readily stays flat and flexible during curing and pyrolyzing to form thin sheets. Precursor materials include polyacrylonitrile (PAN), polymethylacrylonitrile (PMAN), resorcinol/formaldehyde, catechol/formaldehyde, phenol/formaldehyde, etc., or mixtures thereof. These thin films are ideal for use as high power and energy electrodes in batteries, capacitors, and fuel cells, and are potentially useful for capacitive deionization, filtration and catalysis.

  17. Method for making thin carbon foam electrodes

    DOEpatents

    Pekala, Richard W.; Mayer, Steven T.; Kaschmitter, James L.; Morrison, Robert L.

    1999-01-01

    A method for fabricating thin, flat carbon electrodes by infiltrating highly porous carbon papers, membranes, felts, metal fibers/powders, or fabrics with an appropriate carbon foam precursor material. The infiltrated carbon paper, for example, is then cured to form a gel-saturated carbon paper, which is subsequently dried and pyrolyzed to form a thin sheet of porous carbon. The material readily stays flat and flexible during curing and pyrolyzing to form thin sheets. Precursor materials include polyacrylonitrile (PAN), polymethylacrylonitrile (PMAN), resorcinol/formaldehyde, catechol/formaldehyde, phenol/formaldehyde, etc., or mixtures thereof. These thin films are ideal for use as high power and energy electrodes in batteries, capacitors, and fuel cells, and are potentially useful for capacitive deionization, filtration and catalysis.

  18. Mechanical Properties of Silicon Carbonitride Thin Films

    NASA Astrophysics Data System (ADS)

    Peng, Xiaofeng; Hu, Xingfang; Wang, Wei; Song, Lixin

    2003-02-01

    Silicon carbonitride thin films were synthesized by reactive rf sputtering a silicon carbide target in nitrogen and argon atmosphere, or sputtering a silicon nitride target in methane and argon atmosphere, respectively. The Nanoindentation technique (Nanoindenter XP system with a continuous stiffness measurement technique) was employed to measure the hardness and elastic modulus of thin films. The effects of sputtering power on the mechanical properties are different for the two SiCN thin films. With increasing sputtering power, the hardness and the elastic modulus decrease for the former but increase for the latter. The tendency is similar to the evolution trend of Si-C bonds in SiCN materials. This reflects that Si-C bonds provide greater hardness for SiCN thin films than Si-N and C-N bonds.

  19. Carrier lifetimes in thin-film photovoltaics

    NASA Astrophysics Data System (ADS)

    Baek, Dohyun

    2015-09-01

    The carrier lifetimes in thin-film solar cells are reviewed and discussed. Shockley-Read-Hall recombination is dominant at low carrier density, Auger recombination is dominant under a high injection condition and high carrier density, and surface recombination is dominant under any conditions. Because the surface photovoltage technique is insensitive to the surface condition, it is useful for bulk lifetime measurements. The photoconductance decay technique measures the effective recombination lifetime. The time-resolved photoluminescence technique is very useful for measuring thin-film semiconductor or solar-cell materials lifetime, because the sample is thin, other techniques are not suitable for measuring the lifetime. Many papers have provided time-resolved photoluminescence (TRPL) lifetimes for copper-indium-gallium-selenide (CIGS) and CdTe thin-film solar cell. The TRPL lifetime strongly depends on open-circuit voltage and conversion efficiency; however, the TRPL life time is insensitive to the short-circuit current.

  20. Performance Characterization of Monolithic Thin Film Resistors

    NASA Astrophysics Data System (ADS)

    Yin, Rong

    Thin film resistors have a large resistance range and stable performance under high temperature operating condition. Thin film resistors trimmed by laser beam are able to achieve very high precision on resistance value. As a result, thin film resistors have been widely used to improve the performance of integrated circuits such as operational amplifier, analog-to-digital (A/D) and digital -to-analog (D/A) converters, etc. In this dissertation, a new class of thin film resistors, silicon chrome (SiCr) thin film resistors, has been investigated at length. From thin film characterization to aging behavior modelling, we have carried out a series of engineering activities. The characteristics of the SiCr thin film incorporated into three bipolar processes were first determined. After laser trimming, we have measured a couple of physical parameters of the SiCr film in the heat affected zone (HAZ). This is the first time the sheet resistance and the temperature coefficient of resistance (TCR) of thin film in the HAZ have been characterized. Both thermal and d.c. load accelerated aging tests were performed. The test structures were subjected to the aging for 1000 hours. Based on the test data, we not only evaluated the classical thermal aging model for untrimmed thin film resistors, but also established several empirical thermal aging models for trimmed resistors and d.c. load aging models for both trimmed and untrimmed thin film resistors. All the experiments were carried out for both conventional bar resistors and our new Swiss Cheese (SC) resistors. For the first time, the performance of laser trimmed SC resistors, which was experimentally evaluated, shown a clear superiority over that of trimmed bar resistors. Besides these experiments, we have examined different die attach techniques and their effects on thin film resistors. Also, we have developed a number of hardware systems and software tools, such as a temperature controller, d.c. current source, temperature

  1. Thin-film reliability and engineering overview

    NASA Technical Reports Server (NTRS)

    Ross, R. G., Jr.

    1984-01-01

    The reliability and engineering technology base required for thin film solar energy conversions modules is discussed. The emphasis is on the integration of amorphous silicon cells into power modules. The effort is being coordinated with SERI's thin film cell research activities as part of DOE's Amorphous Silicon Program. Program concentration is on temperature humidity reliability research, glass breaking strength research, point defect system analysis, hot spot heating assessment, and electrical measurements technology.

  2. Thin Wall Cast Iron: Phase II

    SciTech Connect

    Doru M. Stefanescu

    2005-07-21

    The development of thin-wall technology allows the designers of energy consuming equipment to select the most appropriate material based on cost/material properties considerations, and not solely on density. The technology developed in this research project will permit the designers working for the automotive industry to make a better informed choice between competing materials and thin wall cast iron, thus decreasing the overall cost of the automobile.

  3. Epitaxial thin film growth in outer space

    NASA Technical Reports Server (NTRS)

    Ignatiev, Alex; Chu, C. W.

    1988-01-01

    A new concept for materials processing in space exploits the ultravacuum component of space for thin-film epitaxial growth. The unique LEO space environment is expected to yield 10-ftorr or better pressures, semiinfinite pumping speeds, and large ultravacuum volume (about 100 cu m) without walls. These space ultravacuum properties promise major improvement in the quality, unique nature, and throughput of epitaxially grown materials, including semiconductors, magnetic materials, and thin-film high-temperature superconductors.

  4. Review of CdO thin films

    NASA Astrophysics Data System (ADS)

    Chandiramouli, R.; Jeyaprakash, B. G.

    2013-02-01

    Cadmium Oxide (CdO) thin film is one of the first transparent conducting oxide semiconductors. Its excellent optical and electronic properties have made CdO a promising material for flat panel displays. In this article, we provide a comprehensive review of the state-of-the-art research activities related to the 'preparation-property-application' triangle of CdO thin films.

  5. Advances in CZTS thin films and nanostructured

    NASA Astrophysics Data System (ADS)

    Ali, N.; Ahmed, R.; Bakhtiar-Ul-Haq; Shaari, A.

    2015-06-01

    Already published data for the optical band gap (Eg) of thin films and nanostructured copper zinc tin sulphide (CZTS) have been reviewed and combined. The vacuum (physical) and non-vacuum (chemical) processes are focused in the study for band gap comparison. The results are accumulated for thin films and nanostructured in different tables. It is inferred from the re- view that the nanostructured material has plenty of worth by engineering the band gap for capturing the maximum photons from solar spectrum.

  6. Internal hypersonic flow. [in thin shock layer

    NASA Technical Reports Server (NTRS)

    Lin, T. C.; Rubin, S. G.

    1974-01-01

    An approach for studying hypersonic internal flow with the aid of a thin-shock-layer approximation is discussed, giving attention to a comparison of thin-shock-layer results with the data obtained on the basis of the imposition theory or a finite-difference integration of the Euler equations. Relations in the case of strong interaction are considered together with questions of pressure distribution and aspects of the boundary-layer solution.

  7. Phase measuring deflectometry for thin actuated mirrors

    NASA Astrophysics Data System (ADS)

    Catling, Tom; Brooks, David; Doel, Peter

    2014-07-01

    In the development of thin active mirrors for future x-ray telescopes there is a need for full field, non-null methods of rapidly characterising highly distorted surfaces without contact. Phase measuring deflectometry, due to its high dynamic range and flexibility, is a promising solution to this problem. In this paper is described a system developed by the authors at University College London, as well as the results of surface measurements using this methodology on thin sheets of actuated glass.

  8. Thin film nitinol microstent for aneurysm occlusion.

    PubMed

    Chun, Youngjae; Levi, Daniel S; Mohanchandra, K P; Vinuela, Fernando; Vinuela, Fernando; Carman, Gregory P

    2009-05-01

    Thin film nitinol produced by sputter deposition was used in the design of microstents intended to treat small vessel aneurysms. Thin film microstents were fabricated by "hot-target" dc sputter deposition. Both stress-strain curves and differential scanning calorimetry curves were generated for the film used to fabricate stents. The films used for stents had an A(f) temperature of approximately 36 degrees C allowing for body activated response from a microcatheter. The 10 microm film was only slightly radio-opaque; thus, a Td marker was attached to the stents to guide fluoroscopic delivery. Thin film microstents were tested in a flow loop with and without nitinol support skeletons to give additional radial support. Stents could be compressed into and easily delivered with <3 Fr catheters. Theoretical frictional and wall drag forces on a thin film nitinol small vessel vascular stent were calculated, and the radial force exerted by thin film stents was evaluated theoretically and experimentally. In vivo studies in swine confirmed that thin film nitinol microstents could be deployed accurately and consistently in the swine cranial vasculature. PMID:19388784

  9. Printable CIGS thin film solar cells

    NASA Astrophysics Data System (ADS)

    Fan, Xiaojuan

    2014-03-01

    Among the various thin film solar cells in the market, CuInGaSe thin film cells have been considered as the most promising alternatives to silicon solar cells because of their high photo-electricity efficiency, reliability, and stability. However, many fabrication of CIGS thin film are based on vacuum processes such as evaporation sputtering techniques which are not cost efficient. This work develops a method using paste or ink liquid spin-coated on glass that would be to conventional ways in terms of cost effective, non-vacuum needed, quick processing. A mixture precursor was prepared by dissolving appropriate amounts of chemicals. After the mixture solution was cooled, a viscous paste prepared and ready for spin-coating process. A slight bluish CIG thin film substrate was then put in a tube furnace with evaporation of metal Se by depositing CdS layer and ZnO nanoparticle thin film coating to a solar cell fabrication. Structure, absorption spectrum, and photo-conversion efficiency for the as-grown CIGS thin film solar cell under study.

  10. Printable CIGS thin film solar cells

    NASA Astrophysics Data System (ADS)

    Fan, Xiaojuan

    2013-03-01

    Among the various thin film solar cells in the market, CuInGaSe thin film solar cells have been considered as the most promising alternatives to crystalline silicon solar cells because of their high photo-electricity conversion efficiency, reliability, and stability. However, many fabrication methods of CIGS thin film are based on vacuum processes such as evaporation and sputtering techniques which are not cost efficient. This work develops a solution method using paste or ink liquid spin-coated on glass that would be competitive to conventional ways in terms of cost effective, non-vacuum needed, and quick processing. A mixture precursor was prepared by dissolving appropriate amounts of composition chemicals. After the mixture solution was cooled, a viscous paste was prepared and ready for spin-coating process. A slight bluish CIG thin film on substrate was then put in a tube furnace with evaporation of metal Se followed by depositing CdS layer and ZnO nanoparticle thin film coating to complete a solar cell fabrication. Structure, absorption spectrum, and photo-electricity conversion efficiency for the as-grown CIGS thin film solar cell are under study.

  11. Research on Advanced Thin Film Batteries

    SciTech Connect

    Goldner, Ronald B.

    2003-11-24

    During the past 7 years, the Tufts group has been carrying out research on advanced thin film batteries composed of a thin film LiCo02 cathode (positive electrode), a thin film LiPON (lithium phosphorous oxynitride) solid electrolyte, and a thin film graphitic carbon anode (negative electrode), under grant DE FG02-95ER14578. Prior to 1997, the research had been using an rfsputter deposition process for LiCoOi and LiPON and an electron beam evaporation or a controlled anode arc evaporation method for depositing the carbon layer. The pre-1997 work led to the deposition of a single layer cell that was successfully cycled for more than 400 times [1,2] and the research also led to the deposition of a monolithic double-cell 7 volt battery that was cycled for more than 15 times [3]. Since 1997, the research has been concerned primarily with developing a research-worthy and, possibly, a production-worthy, thin film deposition process, termed IBAD (ion beam assisted deposition) for depositing each ofthe electrodes and the electrolyte of a completely inorganic solid thin film battery. The main focus has been on depositing three materials - graphitic carbon as the negative electrode (anode), lithium cobalt oxide (nominally LiCoCb) as the positive electrode (cathode), and lithium phosphorus oxynitride (LiPON) as the electrolyte. Since 1998, carbon, LiCoOa, and LiPON films have been deposited using the IBAD process with the following results.

  12. Carbon Nanotube Thin-Film Antennas.

    PubMed

    Puchades, Ivan; Rossi, Jamie E; Cress, Cory D; Naglich, Eric; Landi, Brian J

    2016-08-17

    Multiwalled carbon nanotube (MWCNT) and single-walled carbon nanotube (SWCNT) dipole antennas have been successfully designed, fabricated, and tested. Antennas of varying lengths were fabricated using flexible bulk MWCNT sheet material and evaluated to confirm the validity of a full-wave antenna design equation. The ∼20× improvement in electrical conductivity provided by chemically doped SWCNT thin films over MWCNT sheets presents an opportunity for the fabrication of thin-film antennas, leading to potentially simplified system integration and optical transparency. The resonance characteristics of a fabricated chlorosulfonic acid-doped SWCNT thin-film antenna demonstrate the feasibility of the technology and indicate that when the sheet resistance of the thin film is >40 ohm/sq no power is absorbed by the antenna and that a sheet resistance of <10 ohm/sq is needed to achieve a 10 dB return loss in the unbalanced antenna. The dependence of the return loss performance on the SWCNT sheet resistance is consistent with unbalanced metal, metal oxide, and other CNT-based thin-film antennas, and it provides a framework for which other thin-film antennas can be designed. PMID:27454334

  13. Laser processing for thin-film photovoltaics

    NASA Astrophysics Data System (ADS)

    Compaan, Alvin D.

    1995-04-01

    Over the past decade major advances have occurred in the field of thin- film photovoltaics (PV) with many of them a direct consequence of the application of laser processing. Improved cell efficiencies have been achieved in crystalline and polycrystalline Si, in hydrogenated amorphous silicon, and in two polycrystalline thin-film materials. The use of lasers in photovoltaics includes laser hole drilling for emitter wrap-through, laser trenching for buried bus lines, and laser texturing of crystalline and polycrystalline Si cells. In thin-film devices, laser scribing is gaining increased importance for module interconnects. Pulsed laser recrystallization of boron-doped hydrogenated amorphous silicon is used to form highly conductive p-layers in p-i-n amorphous silicon cells and in thin-film transistors. Optical beam melting appears to be an attractive method for forming metal semiconductor alloys for contact formation. Finally, pulsed lasers are used for deposition of the entire semiconductor absorber layer in two types of polycrystalline thin-film cells-those based on copper indium diselenide and those based on cadmium telluride. In our lab we have prepared and studied heavily doped polycrystalline silicon thin films and also have used laser physical vapor deposition (LPVD) to prepare 'all-LPVD' CdS/CdTe solar cells on glass with efficiencies tested at NREL at 10.5%. LPVD is highly flexible and ideally suited for prototyping PV cells using ternary or quaternary alloys and for exploring new dopant combinations.

  14. Permanent laser conditioning of thin film optical materials

    DOEpatents

    Wolfe, C. Robert; Kozlowski, Mark R.; Campbell, John H.; Staggs, Michael; Rainer, Frank

    1995-01-01

    The invention comprises a method for producing optical thin films with a high laser damage threshold and the resulting thin films. The laser damage threshold of the thin films is permanently increased by irradiating the thin films with a fluence below an unconditioned laser damage threshold.

  15. Permanent laser conditioning of thin film optical materials

    DOEpatents

    Wolfe, C.R.; Kozlowski, M.R.; Campbell, J.H.; Staggs, M.; Rainer, F.

    1995-12-05

    The invention comprises a method for producing optical thin films with a high laser damage threshold and the resulting thin films. The laser damage threshold of the thin films is permanently increased by irradiating the thin films with a fluence below an unconditioned laser damage threshold. 9 figs.

  16. 7 CFR 29.2438 - Thin Leaf (C Group).

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards... Fair Light-brown Thin Leaf. Thin to medium body, mature to ripe, close, lean in oil, inelastic, weak... Light-brown Thin Leaf. Thin to medium body, mature to ripe, close, lean in oil, inelastic, weak,...

  17. 7 CFR 29.2663 - Thin Leaf (C Group).

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards... tolerance. C4L Fair Light-brown Thin Leaf. Thin, mature, close, lean in oil, inelastic, weak, dull finish... Thin Leaf. Thin, mature, close, lean in oil, inelastic, weak, dull finish, pale color intensity,...

  18. Ultra Thin Quantum Well Materials

    SciTech Connect

    Dr Saeid Ghamaty

    2012-08-16

    This project has enabled Hi-Z technology Inc. (Hi-Z) to understand how to improve the thermoelectric properties of Si/SiGe Quantum Well Thermoelectric Materials. The research that was completed under this project has enabled Hi-Z Technology, Inc. (Hi-Z) to satisfy the project goal to understand how to improve thermoelectric conversion efficiency and reduce costs by fabricating ultra thin Si/SiGe quantum well (QW) materials and measuring their properties. In addition, Hi-Z gained critical new understanding on how thin film fabrication increases the silicon substrate's electrical conductivity, which is important new knowledge to develop critical material fabrication parameters. QW materials are constructed with alternate layers of an electrical conductor, SiGe and an electrical insulator, Si. Film thicknesses were varied, ranging from 2nm to 10nm where 10 nm was the original film thickness prior to this work. The optimum performance was determined at a Si and SiGe thickness of 4nm for an electrical current and heat flow parallel to the films, which was an important conclusion of this work. Essential new information was obtained on how the Si substrate electrical conductivity increases by up to an order of magnitude upon deposition of QW films. Test measurements and calculations are accurate and include both the quantum well and the substrate. The large increase in substrate electrical conductivity means that a larger portion of the electrical current passes through the substrate. The silicon substrate's increased electrical conductivity is due to inherent impurities and thermal donors which are activated during both molecular beam epitaxy and sputtering deposition of QW materials. Hi-Z's forward looking cost estimations based on future high performance QW modules, in which the best Seebeck coefficient and electrical resistivity are taken from separate samples predict that the electricity cost produced with a QW module could be achieved at <$0.35/W. This price would

  19. Thin film dielectric composite materials

    DOEpatents

    Jia, Quanxi; Gibbons, Brady J.; Findikoglu, Alp T.; Park, Bae Ho

    2002-01-01

    A dielectric composite material comprising at least two crystal phases of different components with TiO.sub.2 as a first component and a material selected from the group consisting of Ba.sub.1-x Sr.sub.x TiO.sub.3 where x is from 0.3 to 0.7, Pb.sub.1-x Ca.sub.x TiO.sub.3 where x is from 0.4 to 0.7, Sr.sub.1-x Pb.sub.x TiO.sub.3 where x is from 0.2 to 0.4, Ba.sub.1-x Cd.sub.x TiO.sub.3 where x is from 0.02 to 0.1, BaTi.sub.1-x Zr.sub.x O.sub.3 where x is from 0.2 to 0.3, BaTi.sub.1-x Sn.sub.x O.sub.3 where x is from 0.15 to 0.3, BaTi.sub.1-x Hf.sub.x O.sub.3 where x is from 0.24 to 0.3, Pb.sub.1-1.3x La.sub.x TiO.sub.3+0.2x where x is from 0.23 to 0.3, (BaTiO.sub.3).sub.x (PbFeo.sub.0.5 Nb.sub.0.5 O.sub.3).sub.1-x where x is from 0.75 to 0.9, (PbTiO.sub.3).sub.- (PbCo.sub.0.5 W.sub.0.5 O.sub.3).sub.1-x where x is from 0.1 to 0.45, (PbTiO.sub.3).sub.x (PbMg.sub.0.5 W.sub.0.5 O.sub.3).sub.1-x where x is from 0.2 to 0.4, and (PbTiO.sub.3).sub.x (PbFe.sub.0.5 Ta.sub.0.5 O.sub.3).sub.1-x where x is from 0 to 0.2, as the second component is described. The dielectric composite material can be formed as a thin film upon suitable substrates.

  20. Childhood Risk Factors for Thin Body Preoccupation and Social Pressure to Be Thin

    ERIC Educational Resources Information Center

    Agras, W. Stewart; Bryson, Susan; Hammer, Lawrence D.; Kraemer, Helena C.

    2007-01-01

    Objective: Thin body preoccupation and social pressure to be thin (TBPSP) in adolescence are risk factors for the development of full and partial bulimia nervosa and binge eating disorder. This study examined precursors of these potent risk factors. Method: A prospective study followed 134 children from birth to 11.0 years and their parents.…

  1. Amorphous silicon Schottky barrier solar cells incorporating a thin insulating layer and a thin doped layer

    DOEpatents

    Carlson, David E.

    1980-01-01

    Amorphous silicon Schottky barrier solar cells which incorporate a thin insulating layer and a thin doped layer adjacent to the junction forming metal layer exhibit increased open circuit voltages compared to standard rectifying junction metal devices, i.e., Schottky barrier devices, and rectifying junction metal insulating silicon devices, i.e., MIS devices.

  2. Ambient pressure process for preparing aerogel thin films reliquified sols useful in preparing aerogel thin films

    DOEpatents

    Brinker, Charles Jeffrey; Prakash, Sai Sivasankaran

    1999-01-01

    A method for preparing aerogel thin films by an ambient-pressure, continuous process. The method of this invention obviates the use of an autoclave and is amenable to the formation of thin films by operations such as dip coating. The method is less energy intensive and less dangerous than conventional supercritical aerogel processing techniques.

  3. Ferromagnetic properties of fcc Gd thin films

    SciTech Connect

    Bertelli, T. P. Passamani, E. C.; Larica, C.; Nascimento, V. P.; Takeuchi, A. Y.

    2015-05-28

    Magnetic properties of sputtered Gd thin films grown on Si (100) substrates kept at two different temperatures were investigated using X-ray diffraction, ac magnetic susceptibility, and dc magnetization measurements. The obtained Gd thin films have a mixture of hcp and fcc structures, but with their fractions depending on the substrate temperature T{sub S} and film thickness x. Gd fcc samples were obtained when T{sub S} = 763 K and x = 10 nm, while the hcp structure was stabilized for lower T{sub S} (300 K) and thicker film (20 nm). The fcc structure is formed on the Ta buffer layer, while the hcp phase grows on the fcc Gd layer as a consequence of the lattice relaxation process. Spin reorientation phenomenon, commonly found in bulk Gd species, was also observed in the hcp Gd thin film. This phenomenon is assumed to cause the magnetization anomalous increase observed below 50 K in stressed Gd films. Magnetic properties of fcc Gd thin films are: Curie temperature above 300 K, saturation magnetization value of about 175 emu/cm{sup 3}, and coercive field of about 100 Oe at 300 K; features that allow us to classify Gd thin films, with fcc structure, as a soft ferromagnetic material.

  4. Flexible, Ultra-Thin, Embedded Die Packaging

    NASA Astrophysics Data System (ADS)

    McPherson, Ryan J.

    As thin, flexible electronics solutions become more robust, their integration into everyday life becomes more likely. With possible applications in wearable electronics, biomedical sensors, or 'peel and stick' sensors, the reliability of these ultra-thin packages becomes paramount. Likewise, the density achievable with stacked packages benefits greatly from thinner die stacks. To this end, techniques previously developed have demonstrated packages with die thinned to approximately 20mum. Covered in this work are methods for thinning and packaging silicon die, as well as information on common materials used in these processes. The author's contribution is a fabrication process for embedding ultra-thin (approximately 10mum) silicon die in polyimide substrates. This method is fully illustrated in Chapter 3 and enumerated in the Appendix as a quick reference. Additionally, thermal cycle testing of passive daisy chain assemblies has shown promising reliability data. Packages were mounted in three alignments: flat, concave, and convex, and placed into thermal shock testing. Finally, the author discusses possible applications for this fabrication process, including the fabrication of multi-chip-modules.

  5. Optical information storage in PLZT thin films

    SciTech Connect

    Land, C.E.

    1989-01-01

    The feasibility of storing and reading high density optical information in lead zirconate titanate (PZT) and in lead lanthanum zirconate titanate (PLZT) thin films depends on both the longitudinal electrooptic coefficients and the photosensitivities of the films. This paper describes the methods used to measure both the longitudinal electrooptic effects and the photosensitivities of the thin films. The results of these measurements were used to evaluate a longitudinal quadratic electrooptic R coefficient, a linear electrooptic r/sub c/ coefficient and the wavelength dependence of the photosensitivity of a composition of PZT polycrystalline thin film. The longitudinal electrooptic R and r/sub c/ coefficients are about an order of magnitude less than the transverse R and R/sub c/ coefficients of the bulk ceramics of similar compositions. This is attributed to clamping of the film by the rigid substrate. The large birefringence after poling (>10/sup /minus/2/) suggests that the optic axes of the films are preferentially oriented normal to the film surface. The techniques used for evaluating the photosensitivities of the thin films are based on measuring the photocurrent generated rather than the reduction in coercive voltage (used previously for bulk ceramics) when the film is exposed to light. The thin film photosensitivities appear to be about three orders of magnitude higher than those of bulk ceramics of similar compositions. 14 refs., 12 figs., 1 tab.

  6. A high performance thin film thermoelectric cooler

    SciTech Connect

    Rowe, D.M.; Min, G.; Volklein, F.

    1998-07-01

    Thin film thermoelectric devices with small dimensions have been fabricated using microelectronics technology and operated successfully in the Seebeck mode as sensors or generators. However, they do not operate successfully in the Peltier mode as coolers, because of the thermal bypass provided by the relatively thick substrate upon which the thermoelectric device is fabricated. In this paper a processing sequence is described which dramatically reduces this thermal bypass and facilitates the fabrication of high performance integrated thin film thermoelectric coolers. In the processing sequence a very thin amorphous SiC (or SiO{sub 2}SiN{sub 4}) film is deposited on a silicon substrate using conventional thin film deposition and a membrane formed by removing the silicon substrate over a desired region using chemical etching or micro-machining. Thermoelements are deposited on the membrane using conventional thin film deposition and patterning techniques and configured so that the region which is to be cooled is abutted to the cold junctions of the Peltier thermoelements while the hot junctions are located at the outer peripheral area which rests on the silicon substrate rim. Heat is pumped laterally from the cooled region to the silicon substrate rim and then dissipated vertically through it to an external heat sink. Theoretical calculations of the performance of a cooler described above indicate that a maximum temperature difference of about 40--50K can be achieved with a maximum heat pumping capacity of around 10 milliwatts.

  7. Nuclear Propulsion using Thin Foiled Fuel

    NASA Astrophysics Data System (ADS)

    Takahashi, H.

    1998-11-01

    A new way to produce plasma for nuclear propulsion is proposed. A thin foiled fuel can be used for converting fission energy to propulsion energy efficiently. The fission products coming out of the thin foil directly ionize the hydrogen molecules which are used for propulsion. Thus very small portion of fission energy deposited in the thin foil, and integrity of the thin foiled fuel can be maintained even in high nuclear power. Fuel material with large thermal fission cross-section is preferable to make thin foiled fuel and the heat deposition in the foil can be reduced. To get high power from the foiled fuel assembly, thermal neutrons which are created out from the assembly can be supplied, or the assembly itself can create the high intensity thermal neutrons by self-multiplication. A flexible design of a highly efficient nuclear propulsion system can be made. The thickness of the foil and the maintenance of the thermo-mechanical integrity can be determined from the fission cross-section and the slowing down power for fission products. The talk discusses the issues related to heat removal from the assembly.

  8. Thin Ice Films at Mineral Surfaces.

    PubMed

    Yeşilbaş, Merve; Boily, Jean-François

    2016-07-21

    Ice films formed at mineral surfaces are of widespread occurrence in nature and are involved in numerous atmospheric and terrestrial processes. In this study, we studied thin ice films at surfaces of 19 synthetic and natural mineral samples of varied structure and composition. These thin films were formed by sublimation of thicker hexagonal ice overlayers mostly produced by freezing wet pastes of mineral particles at -10 and -50 °C. Vibration spectroscopy revealed that thin ice films contained smaller populations of strongly hydrogen-bonded water molecules than in hexagonal ice and liquid water. Thin ice films at the surfaces of the majority of minerals considered in this work [i.e., metal (oxy)(hydr)oxides, phyllosilicates, silicates, volcanic ash, Arizona Test Dust] produced intense O-H stretching bands at ∼3400 cm(-1), attenuated bands at ∼3200 cm(-1), and liquid-water-like bending band at ∼1640 cm(-1) irrespective of structure and composition. Illite, a nonexpandable phyllosilicate, is the only mineral that stabilized a form of ice that was strongly resilient to sublimation in temperatures as low as -50 °C. As mineral-bound thin ice films are the substrates upon which ice grows from water vapor or aqueous solutions, this study provides new constraints from which their natural occurrences can be understood. PMID:27377606

  9. The preparation of ACEL thin films

    NASA Astrophysics Data System (ADS)

    Vecht, Aron

    1990-05-01

    Although thin film ACEL devices have become commercially available, the number of companies producing these displays has continued to diminish. The cause of their demise was not display performance, as both sufficient brightness and efficiency has been achieved, but the low return on the heavy capital investment due to the poor yields obtained in production. In order to make ACEL thin film devices more viable, the capital investment needs to be low and/or the production yields high. Opting for relatively expensive sputtering or ALE techniques as the sole methods of fabricating EL structures, is both commercially and scientifically ill-advised. Considerable effort was spent in developing cheaper alternative techniques for thin film deposition. The main objectives of the contract can be summarized as follows: (1) to deposit high quality ZnS thin films by MOCVD, (2) to dope the ZnS thin film with Mn, (3) to deposit high quality dielectric films using a novel spray pyrolysis process, (4) to evaluate optimized insulator/ZnS-Mn/insulator structures, and (5) the fabrication of large area XY matrix ACEL structures.

  10. Thin film absorber for a solar collector

    DOEpatents

    Wilhelm, William G.

    1985-01-01

    This invention pertains to energy absorbers for solar collectors, and more particularly to high performance thin film absorbers. The solar collectors comprising the absorber of this invention overcome several problems seen in current systems, such as excessive hardware, high cost and unreliability. In the preferred form, the apparatus features a substantially rigid planar frame with a thin film window bonded to one planar side of the frame. An absorber in accordance with the present invention is comprised of two thin film layers that are sealed perimetrically. In a preferred embodiment, thin film layers are formed from a metal/plastic laminate. The layers define a fluid-tight planar envelope of large surface area to volume through which a heat transfer fluid flows. The absorber is bonded to the other planar side of the frame. The thin film construction of the absorber assures substantially full envelope wetting and thus good efficiency. The window and absorber films stress the frame adding to the overall strength of the collector.

  11. Thinning of current sheets and magnetic reconnection

    NASA Astrophysics Data System (ADS)

    Singh, N.; Deverapalli, C.

    Using three-dimensional particle-in-cell (3DPIC) simulations, we study the formation of a thin current sheet. The processes associated with thin current sheets reported here include its thinning, associated potential well in its central part, ion acceleration into the well, current-driven ion mode instabilities, electron and ion heating, current sheet re- broadening, current disruption in the central part of the current sheet and magnetic reconnection. It is shown that current driven instabilities become explosive when the preferential heating of electrons by the ions make electron temperature higher than that of the ions. This explosive stage is associated with high plasma resistivity, current disruption and bifurcated current sheets. The current disruption is linked to the magnetic reconnection.

  12. Capillary stress in microporous thin films

    SciTech Connect

    Samuel, J.; Hurd, A.J.; Frink, L.J.D.; Swol, F. van; Brinker, C.J. |; Raman, N.K.

    1996-06-01

    Development of capillary stress in porous xerogels, although ubiquitous, has not been systematically studied. The authors have used the beam bending technique to measure stress isotherms of microporous thin films prepared by a sol-gel route. The thin films were prepared on deformable silicon substrates which were then placed in a vacuum system. The automated measurement was carried out by monitoring the deflection of a laser reflected off the substrate while changing the overlying relative pressure of various solvents. The magnitude of the macroscopic bending stress was found to reach a value of 180 MPa at a relative pressure of methanol, P/Po = 0.001. The observed stress is determined by the pore size distribution and is an order of magnitude smaller in mesoporous thin films. Density Functional Theory (DFT) indicates that for the microporous materials, the stress at saturation is compressive and drops as the relative pressure is reduced.

  13. Method for making thin polypropylene film

    DOEpatents

    Behymer, R.D.; Scholten, J.A.

    1985-11-21

    An economical method is provided for making uniform thickness polypropylene film as thin as 100 Angstroms. A solution of polypropylene dissolved in xylene is formed by mixing granular polypropylene and xylene together in a flask at an elevated temperature. A substrate, such as a glass plate or microscope slide is immersed in the solution. When the glass plate is withdrawn from the solution at a uniform rate, a thin polypropylene film forms on a flat surface area of the glass plate as the result of xylene evaporation. The actual thickness of the polypropylene film is functional of the polypropylene in xylene solution concentration, and the particular withdrawal rate of the glass plate from the solution. After formation, the thin polypropylene film is floated from the glass plate onto the surface of water, from which it is picked up with a wire hoop.

  14. Microstructural evolution of tungsten oxide thin films

    NASA Astrophysics Data System (ADS)

    Hembram, K. P. S. S.; Thomas, Rajesh; Rao, G. Mohan

    2009-10-01

    Tungsten oxide thin films are of great interest due to their promising applications in various optoelectronic thin film devices. We have investigated the microstructural evolution of tungsten oxide thin films grown by DC magnetron sputtering on silicon substrate. The structural characterization and surface morphology were carried out using X-ray diffraction and Scanning Electron Microscopy (SEM). The as deposited films were amorphous, where as, the films annealed above 400 °C were crystalline. In order to explain the microstructural changes due to annealing, we have proposed a "instability wheel" model for the evolution of the microstructure. This model explains the transformation of mater into various geometries within them selves, followed by external perturbation.

  15. Vibration welding system with thin film sensor

    DOEpatents

    Cai, Wayne W; Abell, Jeffrey A; Li, Xiaochun; Choi, Hongseok; Zhao, Jingzhou

    2014-03-18

    A vibration welding system includes an anvil, a welding horn, a thin film sensor, and a process controller. The anvil and horn include working surfaces that contact a work piece during the welding process. The sensor measures a control value at the working surface. The measured control value is transmitted to the controller, which controls the system in part using the measured control value. The thin film sensor may include a plurality of thermopiles and thermocouples which collectively measure temperature and heat flux at the working surface. A method includes providing a welder device with a slot adjacent to a working surface of the welder device, inserting the thin film sensor into the slot, and using the sensor to measure a control value at the working surface. A process controller then controls the vibration welding system in part using the measured control value.

  16. Thin film ferroelectric electro-optic memory

    NASA Technical Reports Server (NTRS)

    Thakoor, Sarita (Inventor); Thakoor, Anilkumar P. (Inventor)

    1993-01-01

    An electrically programmable, optically readable data or memory cell is configured from a thin film of ferroelectric material, such as PZT, sandwiched between a transparent top electrode and a bottom electrode. The output photoresponse, which may be a photocurrent or photo-emf, is a function of the product of the remanent polarization from a previously applied polarization voltage and the incident light intensity. The cell is useful for analog and digital data storage as well as opto-electric computing. The optical read operation is non-destructive of the remanent polarization. The cell provides a method for computing the product of stored data and incident optical data by applying an electrical signal to store data by polarizing the thin film ferroelectric material, and then applying an intensity modulated optical signal incident onto the thin film material to generate a photoresponse therein related to the product of the electrical and optical signals.

  17. Mesoscale morphologies in polymer thin films.

    SciTech Connect

    Ramanathan, M.; Darling, S. B.

    2011-06-01

    In the midst of an exciting era of polymer nanoscience, where the development of materials and understanding of properties at the nanoscale remain a major R&D endeavor, there are several exciting phenomena that have been reported at the mesoscale (approximately an order of magnitude larger than the nanoscale). In this review article, we focus on mesoscale morphologies in polymer thin films from the viewpoint of origination of structure formation, structure development and the interaction forces that govern these morphologies. Mesoscale morphologies, including dendrites, holes, spherulites, fractals and honeycomb structures have been observed in thin films of homopolymer, copolymer, blends and composites. Following a largely phenomenological level of description, we review the kinetic and thermodynamic aspects of mesostructure formation outlining some of the key mechanisms at play. We also discuss various strategies to direct, limit, or inhibit the appearance of mesostructures in polymer thin films as well as an outlook toward potential areas of growth in this field of research.

  18. Electrostatic thin film chemical and biological sensor

    DOEpatents

    Prelas, Mark A.; Ghosh, Tushar K.; Tompson, Jr., Robert V.; Viswanath, Dabir; Loyalka, Sudarshan K.

    2010-01-19

    A chemical and biological agent sensor includes an electrostatic thin film supported by a substrate. The film includes an electrostatic charged surface to attract predetermined biological and chemical agents of interest. A charge collector associated with said electrostatic thin film collects charge associated with surface defects in the electrostatic film induced by the predetermined biological and chemical agents of interest. A preferred sensing system includes a charge based deep level transient spectroscopy system to read out charges from the film and match responses to data sets regarding the agents of interest. A method for sensing biological and chemical agents includes providing a thin sensing film having a predetermined electrostatic charge. The film is exposed to an environment suspected of containing the biological and chemical agents. Quantum surface effects on the film are measured. Biological and/or chemical agents can be detected, identified and quantified based on the measured quantum surface effects.

  19. Simulated Thin-Film Growth and Imaging

    NASA Astrophysics Data System (ADS)

    Schillaci, Michael

    2001-06-01

    Thin-films have become the cornerstone of the electronics, telecommunications, and broadband markets. A list of potential products includes: computer boards and chips, satellites, cell phones, fuel cells, superconductors, flat panel displays, optical waveguides, building and automotive windows, food and beverage plastic containers, metal foils, pipe plating, vision ware, manufacturing equipment and turbine engines. For all of these reasons a basic understanding of the physical processes involved in both growing and imaging thin-films can provide a wonderful research project for advanced undergraduate and first-year graduate students. After producing rudimentary two- and three-dimensional thin-film models incorporating ballsitic deposition and nearest neighbor Coulomb-type interactions, the QM tunneling equations are used to produce simulated scanning tunneling microscope (SSTM) images of the films. A discussion of computational platforms, languages, and software packages that may be used to accomplish similar results is also given.

  20. A microfabricated sensor for thin dielectric layers.

    PubMed

    Fierlinger, P; DeVoe, R; Flatt, B; Gratta, G; Green, M; Kolkowitz, S; Leport, F; Montero Diez, M; Neilson, R; O'Sullivan, K; Pocar, A; Wodin, J

    2008-04-01

    We describe a sensor for the measurement of thin dielectric layers capable of operation in a variety of environments. The sensor is obtained by microfabricating a capacitor with interleaved aluminum fingers, exposed to the dielectric to be measured. In particular, the device can measure thin layers of solid frozen from a liquid or gaseous medium. Sensitivity to single atomic layers is achievable in many configurations and, by utilizing fast, high sensitivity capacitance readout in a feedback system onto environmental parameters; coatings of few layers can be dynamically maintained. We discuss the design, readout, and calibration of several versions of the device optimized in different ways. We specifically dwell on the case in which atomically thin solid xenon layers are grown and stabilized, in cryogenic conditions, from a liquid xenon bath. PMID:18447546

  1. Coalescence and percolation in thin metal films

    SciTech Connect

    Yu, X.; Duxbury, P.M.; Jeffers, G.; Dubson, M.A. Center for Fundamental Materials Research, Michigan State University, East Lansing, Michigan 48824-1116 )

    1991-12-15

    Metals thermally evaporated onto warm insulating substrates evolve to the thin-film state via the morphological sequence: compact islands, elongated islands, percolation, hole filling, and finally the thin-film state. The coverage at which the metal percolates ({ital p}{sub {ital c}}) is often considerably higher than that predicted by percolation models, such as inverse swiss cheese or lattice percolation. Using a simple continuum model, we show that high-{ital p}{sub {ital c}}'s arise naturally in thin films that exhibit a crossover from full coalescence of islands at early stages of growth to partial coalescence at later stages. In this interrupted-coalescence model, full coalescence of islands occurs up to a critical island radius {ital R}{sub {ital c}}, after which islands overlap, but do not fully coalesce. We present the morphology of films and the critical area coverages generated by this model.

  2. AES analysis of barium fluoride thin films

    NASA Astrophysics Data System (ADS)

    Kashin, G. N.; Makhnjuk, V. I.; Rumjantseva, S. M.; Shchekochihin, Ju. M.

    1993-06-01

    AES analysis of thin films of metal fluorides is a difficult problem due to charging and decomposition of such films under electron bombardment. We have developed a simple algorithm for a reliable quantitative AES analysis of metal fluoride thin films (BaF 2 in our work). The relative AES sensitivity factors for barium and fluorine were determined from BaF 2 single-crystal samples. We have investigated the dependence of composition and stability of barium fluoride films on the substrate temperature during film growth. We found that the instability of BaF 2 films grown on GaAs substrates at high temperatures (> 525°C) is due to a loss of fluorine. Our results show that, under the optimal electron exposure conditions, AES can be used for a quantitative analysis of metal fluoride thin films.

  3. Tungsten-doped thin film materials

    DOEpatents

    Xiang, Xiao-Dong; Chang, Hauyee; Gao, Chen; Takeuchi, Ichiro; Schultz, Peter G.

    2003-12-09

    A dielectric thin film material for high frequency use, including use as a capacitor, and having a low dielectric loss factor is provided, the film comprising a composition of tungsten-doped barium strontium titanate of the general formula (Ba.sub.x Sr.sub.1-x)TiO.sub.3, where X is between about 0.5 and about 1.0. Also provided is a method for making a dielectric thin film of the general formula (Ba.sub.x Sr.sub.1-x)TiO.sub.3 and doped with W, where X is between about 0.5 and about 1.0, a substrate is provided, TiO.sub.2, the W dopant, Ba, and optionally Sr are deposited on the substrate, and the substrate containing TiO.sub.2, the W dopant, Ba, and optionally Sr is heated to form a low loss dielectric thin film.

  4. Thin Film Transistors On Plastic Substrates

    DOEpatents

    Carey, Paul G.; Smith, Patrick M.; Sigmon, Thomas W.; Aceves, Randy C.

    2004-01-20

    A process for formation of thin film transistors (TFTs) on plastic substrates replaces standard thin film transistor fabrication techniques, and uses sufficiently lower processing temperatures so that inexpensive plastic substrates may be used in place of standard glass, quartz, and silicon wafer-based substrates. The silicon based thin film transistor produced by the process includes a low temperature substrate incapable of withstanding sustained processing temperatures greater than about 250.degree. C., an insulating layer on the substrate, a layer of silicon on the insulating layer having sections of doped silicon, undoped silicon, and poly-silicon, a gate dielectric layer on the layer of silicon, a layer of gate metal on the dielectric layer, a layer of oxide on sections of the layer of silicon and the layer of gate metal, and metal contacts on sections of the layer of silicon and layer of gate metal defining source, gate, and drain contacts, and interconnects.

  5. Refraction in electrically thin inhomogeneous media.

    PubMed

    Ruphuy, Miguel; Ramahi, Omar M

    2016-04-01

    This work presents a new formulation for refraction from flat electrically thin lenses and reflectors comprised of inhomogeneous material. Inhomogeneous electrically thin flat lenses and reflectors cannot make use of the Snell law since this classical formulation works solely at interfaces of planar homogeneous media. The refraction of a perpendicularly incident plane wave at a planar interface is physically explained through the phase advance of the rays within the medium. The Huygens principle is then used to construct the refracted wavefront. The formulation is validated using numerical full wave simulation for several examples where the refractive angle is predicted with good accuracy. Furthermore, the formulation gives a physical insight of the phenomenon of refraction from electrically thin inhomogeneous media. PMID:27140761

  6. Method for synthesizing thin film electrodes

    DOEpatents

    Boyle, Timothy J.

    2007-03-13

    A method for making a thin-film electrode, either an anode or a cathode, by preparing a precursor solution using an alkoxide reactant, depositing multiple thin film layers with each layer approximately 500 1000 .ANG. in thickness, and heating the layers to above 600.degree. C. to achieve a material with electrochemical properties suitable for use in a thin film battery. The preparation of the anode precursor solution uses Sn(OCH.sub.2C(CH.sub.3).sub.3).sub.2 dissolved in a solvent in the presence of HO.sub.2CCH.sub.3 and the cathode precursor solution is formed by dissolving a mixture of (Li(OCH.sub.2C(CH.sub.3).sub.3)).sub.8 and Co(O.sub.2CCH.sub.3).H.sub.2O in at least one polar solvent.

  7. Free thin paraumbilical perforator-based flaps.

    PubMed

    Koshima, I; Moriguchi, T; Soeda, S; Tanaka, H; Umeda, N

    1992-07-01

    A free paraumbilical perforator-based flap fed by a muscle perforator from the inferior deep epigastric artery and with no muscle was used in 13 patients. Among them, a free thin paraumbilical perforator-based flap with a thin layer of fat, to protect the subdermal plexus of the vessels, was used in seven patients. The dominant pedicle perforator of this thin flap is usually located around the umbilicus and a large flap can be obtained. Its critical length-to-breath ratio is considered to be 4:3. The advantages of this flap are a long and large vascular pedicle, rare postoperative abdominal herniation, little bulkiness of the flap, and a relatively large skin territory. The disadvantages are technical difficulties in dissection of the perforator and anatomical variation in the location of the perforator. We believe this flap largely overcomes the problems of the conventional rectus abdominis musculocutaneous flap. PMID:1386718

  8. Infrared radiation of thin plastic films.

    NASA Technical Reports Server (NTRS)

    Tien, C. L.; Chan, C. K.; Cunnington, G. R.

    1972-01-01

    A combined analytical and experimental study is presented for infrared radiation characteristics of thin plastic films with and without a metal substrate. On the basis of the thin-film analysis, a simple analytical technique is developed for determining band-averaged optical constants of thin plastic films from spectral normal transmittance data for two different film thicknesses. Specifically, the band-averaged optical constants of polyethylene terephthalate and polyimide were obtained from transmittance measurements of films with thicknesses in the range of 0.25 to 3 mil. The spectral normal reflectance and total normal emittance of the film side of singly aluminized films are calculated by use of optical constants; the results compare favorably with measured values.

  9. Synthesis of periodic mesoporous silica thin films

    SciTech Connect

    Anderson, M.T.; Martin, J.E.; Odinek, J.G.; Newcomer, P.

    1996-06-01

    We have synthesized periodic mesoporous silica thin films from homogeneous solutions. To synthesize the films, a thin layer of a pH 7 micellar coating solution that contains TMOS (tetramethoxysilane) is dip or spin-coated onto Si wafers, borosilicate glass, or quartz substrates. NH3 gas is diffused into the solution and causes rapid hydrolysis and condensation of the TMOS and the formation of periodic mesoporous thin films within 10 seconds. Combination of homogenous solutions and rapid product formation maximizes the concentration of the desired product and provides a controlled, predictable microstructure. The films have been made continuous and crack-free by optimizing initial silica concentration and film thickness. The films are being evaluated as high surface area, size-selective coatings for surface acoustic wave (SAW) sensors.

  10. Geometry of thin liquid sheet flows

    NASA Technical Reports Server (NTRS)

    Chubb, Donald L.; Calfo, Frederick D.; Mcconley, Marc W.; Mcmaster, Matthew S.; Afjeh, Abdollah A.

    1994-01-01

    Incompresible, thin sheet flows have been of research interest for many years. Those studies were mainly concerned with the stability of the flow in a surrounding gas. Squire was the first to carry out a linear, invicid stability analysis of sheet flow in air and compare the results with experiment. Dombrowski and Fraser did an experimental study of the disintegration of sheet flows using several viscous liquids. They also detected the formulation of holes in their sheet flows. Hagerty and Shea carried out an inviscid stability analysis and calculated growth rates with experimental values. They compared their calculated growth rates with experimental values. Taylor studied extensively the stability of thin liquid sheets both theoretically and experimentally. He showed that thin sheets in a vacuum are stable. Brown experimentally investigated thin liquid sheet flows as a method of application of thin films. Clark and Dumbrowski carried out second-order stability analysis for invicid sheet flows. Lin introduced viscosity into the linear stability analysis of thin sheet flows in a vacuum. Mansour and Chigier conducted an experimental study of the breakup of a sheet flow surrounded by high-speed air. Lin et al. did a linear stability analysis that included viscosity and a surrounding gas. Rangel and Sirignano carried out both a linear and nonlinear invisid stability analysis that applies for any density ratio between the sheet liquid and the surrounding gas. Now there is renewed interest in sheet flows because of their possible application as low mass radiating surfaces. The objective of this study is to investigate the fluid dynamics of sheet flows that are of interest for a space radiator system. Analytical expressions that govern the sheet geometry are compared with experimental results. Since a space radiator will operate in a vacuum, the analysis does not include any drag force on the sheet flow.

  11. Axisymmetric instability in a thinning electrified jet

    NASA Astrophysics Data System (ADS)

    Dharmansh; Chokshi, Paresh

    2016-04-01

    The axisymmetric stability of an electrified jet is analyzed under electrospinning conditions using the linear stability theory. The fluid is considered Newtonian with a finite electrical conductivity, modeled as a leaky dielectric medium. While the previous studies impose axisymmetric disturbances on a cylindrical jet of uniform radius, referred to as the base state, in the present study the actual thinning jet profile, obtained as the steady-state solution of the one-dimensional slender filament model, is treated as the base state. The analysis takes into account the role of variation in the jet variables like radius, velocity, electric field, and surface charge density along the thinning jet in the stability behavior. The eigenspectrum of the axisymmetric disturbance growth rate is constructed from the linearized disturbance equations discretized using the Chebyshev collocation method. The most unstable growth rate for the thinning jet is significantly different from that for the uniform radius jet. For the same electrospinning conditions, while the uniform radius jet is predicted to be highly unstable, the thinning jet profile is found to be unstable but with a relatively very low growth rate. The stabilizing role of the thinning jet is attributed to the variation in the surface charge density as well as the extensional deformation rate in the fluid ignored in the uniform radius jet analysis. The dominant mode for the thinning jet is an oscillatory conducting mode driven by the field-charge coupling. The disturbance energy balance finds the electric force to be the dominant force responsible for the disturbance growth, potentially leading to bead formation along the fiber. The role of various material and process parameters in the stability behavior is also investigated.

  12. Photonics applications of nanostructured thin films

    NASA Astrophysics Data System (ADS)

    Kennedy, Scott Ronald

    Using an advanced thin film fabrication technique known as Glancing Angle Deposition (GLAD), it is possible to fabricate unique thin film nanostructures with characteristic dimensions on the order of a wavelength of light. By tailoring the morphologies of the films, they can be designed to exhibit particular optical properties that can be customized through advanced substrate motion and highly oblique flux incidence angles. In applications to photonics, controlling the flow of light for a specified task, GLAD thin films can be fabricated to provide the ability to manipulate incident light through controlled interactions of optical frequency electromagnetic radiation with the thin film nanostructures. Tetragonal square spiral photonic band gap crystals, a new class of periodic dielectric material that is characterized by the elimination of the density of states for frequencies lying in the stop gap of the crystal, can be fabricated using GLAD in a virtual single step process. The design and fabrication of these unique devices has been performed and the resultant crystals characterized in terms of optical response with respect to forbidden propagation modes, material properties, and advanced deposition techniques used to improve the overall structure. Chiral or helical thin films deposited using GLAD were also investigated, and have been shown to exhibit optical activity and circular birefringence due to their inherent structural anisotropy. It has been shown that the addition of nematic liquid crystals (LCs) to chiral thin films enhances the overall device performance due to order induced in the LCs by the film structure. This effect was investigated for a variety of materials and film structures. Finally, by developing a modified GLAD technique whereby the deposited film porosity is controlled through the angle of flux incidence, porous broadband antireflection coatings were produced. Using an appropriate effective medium theory to describe the index of refraction

  13. Thin-shell instability in collisionless plasma

    NASA Astrophysics Data System (ADS)

    Dieckmann, M. E.; Ahmed, H.; Doria, D.; Sarri, G.; Walder, R.; Folini, D.; Bret, A.; Ynnerman, A.; Borghesi, M.

    2015-09-01

    Thin-shell instability is one process which can generate entangled structures in astrophysical plasma on collisional (fluid) scales. It is driven by a spatially varying imbalance between the ram pressure of the inflowing upstream plasma and the downstream's thermal pressure at a nonplanar shock. Here we show by means of a particle-in-cell simulation that an analog process can destabilize a thin shell formed by two interpenetrating, unmagnetized, and collisionless plasma clouds. The amplitude of the shell's spatial modulation grows and saturates after about ten inverse proton plasma frequencies, when the shell consists of connected piecewise linear patches.

  14. Feasibility Study of Thin Film Thermocouple Piles

    NASA Technical Reports Server (NTRS)

    Sisk, R. C.

    2001-01-01

    Historically, thermopile detectors, generators, and refrigerators based on bulk materials have been used to measure temperature, generate power for spacecraft, and cool sensors for scientific investigations. New potential uses of small, low-power, thin film thermopiles are in the area of microelectromechanical systems since power requirements decrease as electrical and mechanical machines shrink in size. In this research activity, thin film thermopile devices are fabricated utilizing radio frequency sputter coating and photoresist lift-off techniques. Electrical characterizations are performed on two designs in order to investigate the feasibility of generating small amounts of power, utilizing any available waste heat as the energy source.

  15. Thin-film Rechargeable Lithium Batteries

    DOE R&D Accomplishments Database

    Dudney, N. J.; Bates, J. B.; Lubben, D.

    1995-06-01

    Thin film rechargeable lithium batteries using ceramic electrolyte and cathode materials have been fabricated by physical deposition techniques. The lithium phosphorous oxynitride electrolyte has exceptional electrochemical stability and a good lithium conductivity. The lithium insertion reaction of several different intercalation materials, amorphous V{sub 2}O{sub 5}, amorphous LiMn{sub 2}O{sub 4}, and crystalline LiMn{sub 2}O{sub 4} films, have been investigated using the completed cathode/electrolyte/lithium thin film battery.

  16. Dynamic delamination of patterned thin films

    NASA Astrophysics Data System (ADS)

    Kandula, Soma S. V.; Tran, Phuong; Geubelle, Philippe H.; Sottos, Nancy R.

    2008-12-01

    We investigate laser-induced dynamic delamination of a patterned thin film on a substrate. Controlled delamination results from our insertion of a weak adhesion region beneath the film. The inertial forces acting on the weakly bonded portion of the film lead to stable propagation of a crack along the film/substrate interface. Through a simple energy balance, we extract the critical energy for interfacial failure, a quantity that is difficult and sometimes impossible to characterize by more conventional methods for many thin film/substrate combinations.

  17. Thin-film rechargeable lithium batteries

    SciTech Connect

    Dudney, N.J.; Bates, J.B.; Lubben, D.

    1995-06-01

    Thin-film rechargeable lithium batteries using ceramic electrolyte and cathode materials have been fabricated by physical deposition techniques. The lithium phosphorous oxynitride electrolyte has exceptional electrochemical stability and a good lithium conductivity. The lithium insertion reaction of several different intercalation materials, amorphous V{sub 2}O{sub 5}, amorphous LiMn{sub 2}O{sub 4}, and crystalline LiMn{sub 2}O{sub 4} films, have been investigated using the completed cathode/electrolyte/lithium thin-film battery.

  18. Borocarbide thin films and tunneling measurements.

    SciTech Connect

    Iavarone, M.; Andreone, A.; Cassinese, A.; Dicapual, R.; giannil, L.; Vagliol, R.; DeWilde, Y.; Crabtree, G. W.

    2000-06-15

    The results obtained by their group in thin film fabrication and STM tunneling on superconducting borocarbides YNi{sub 2}B{sub 2}C have been be briefly reviewed. Results concerning the microwave surface impedance and the S/N planar junctions on LuNi{sub 2}B{sub 2}C thin films have been also presented and analyzed. These new data unambiguously confirm the full BCS nature of the superconducting gap in borocarbides and the absence of significant pair-breaking effects in LuNi{sub 2}B{sub 2}C.

  19. Stability analysis of dynamic thin shells

    NASA Astrophysics Data System (ADS)

    Lobo, Francisco S. N.; Crawford, Paulo

    2005-11-01

    We analyse the stability of generic spherically symmetric thin shells to linearized perturbations around static solutions. We include the momentum flux term in the conservation identity, deduced from the 'ADM' constraint and the Lanczos equations. Following the Ishak Lake analysis, we deduce a master equation which dictates the stable equilibrium configurations. Considering the transparency condition, we study the stability of thin shells around black holes, showing that our analysis is in agreement with previous results. Applying the analysis to traversable wormhole geometries, by considering specific choices for the form function, we deduce stability regions and find that the latter may be significantly increased by considering appropriate choices for the redshift function.

  20. Emittance Theory for Thin Film Selective Emitter

    NASA Technical Reports Server (NTRS)

    Chubb, Donald L.; Lowe, Roland A.; Good, Brian S.

    1994-01-01

    Thin films of high temperature garnet materials such as yttrium aluminum garnet (YAG) doped with rare earths are currently being investigated as selective emitters. This paper presents a radiative transfer analysis of the thin film emitter. From this analysis the emitter efficiency and power density are calculated. Results based on measured extinction coefficients for erbium-YAG and holmium-YAG are presented. These results indicated that emitter efficiencies of 50 percent and power densities of several watts/sq cm are attainable at moderate temperatures (less than 1750 K).

  1. Ion beam-based characterization of multicomponent oxide thin films and thin film layered structures

    SciTech Connect

    Krauss, A.R.; Rangaswamy, M.; Lin, Yuping; Gruen, D.M.; Schultz, J.A.; Schmidt, H.K.; Chang, R.P.H.

    1992-11-01

    Fabrication of thin film layered structures of multi-component materials such as high temperature superconductors, ferroelectric and electro-optic materials, and alloy semiconductors, and the development of hybrid materials requires understanding of film growth and interface properties. For High Temperature Superconductors, the superconducting coherence length is extremely short (5--15 {Angstrom}), and fabrication of reliable devices will require control of film properties at extremely sharp interfaces; it will be necessary to verify the integrity of thin layers and layered structure devices over thicknesses comparable to the atomic layer spacing. Analytical techniques which probe the first 1--2 atomic layers are therefore necessary for in-situ characterization of relevant thin film growth processes. However, most surface-analytical techniques are sensitive to a region within 10--40 {Angstrom} of the surface and are physically incompatible with thin film deposition and are typically restricted to ultra high vacuum conditions. A review of ion beam-based analytical methods for the characterization of thin film and multi-layered thin film structures incorporating layers of multicomponent oxides is presented. Particular attention will be paid to the use of time-of-flight techniques based on the use of 1- 15 key ion beams which show potential for use as nondestructive, real-time, in-situ surface diagnostics for the growth of multicomponent metal and metal oxide thin films.

  2. Isotropic thin-walled pressure vessel experiment

    NASA Technical Reports Server (NTRS)

    Denton, Nancy L.; Hillsman, Vernon S.

    1992-01-01

    The objectives are: (1) to investigate the stress and strain distributions on the surface of a thin walled cylinder subject to internal pressure and/or axial load; and (2) to relate stress and strain distributions to material properties and cylinder geometry. The experiment, supplies, and procedure are presented.

  3. On the Theory of Thin Shallow Shells

    NASA Technical Reports Server (NTRS)

    Nazarov, A. A.

    1956-01-01

    This report is concerned with the theory of thin shallow shells. It does not employ the lines of curvature as the coordinate system, but employs "almost cartesian coordinates" or the coordinates obtained by cutting the surface into two mutually orthogonal systems of parallel planes.

  4. Thin-disk solid state lasers

    NASA Astrophysics Data System (ADS)

    Giesen, Adolf

    2004-12-01

    The principle ideas of the thin disk laser design will be illustrated and the advantages for operating different laser materials will be explained. The results for cw- and q-switched operation as well as for amplification of short (ns) and ultra-short (ps, fs) pulses demonstrate the potential of the thin disk laser design. The scaling laws for this laser design show that the power limit for cw-operation is far beyond 10 kW for one single disk and the energy limit is higher than 1 J from one disk in pulsed operation. Also the applicability of the thin disk laser concept to optically pumped semiconductor structures will be discussed. When pumping directly into the quantum wells the energy defect between pump- and laser photon can be smaller than 5% thus reducing the waste heat generated inside the semiconductor structure. First results demonstrate the potential of this new concept. Finally, a short overview of the industrial realization of the thin disk laser technology will be given.

  5. Considering Thin Client Computing for Higher Education.

    ERIC Educational Resources Information Center

    Sheehan, Mark

    1998-01-01

    In response to concerns about the cost of keeping up with individual desktop computing technology, several new solutions have emerged. Referred to as "thin clients," or network-centric computers, they include two types of desktop device: the network computer and the Windows terminal. Purchase cost, life span, support costs, and overall total cost…

  6. Thin film thermocouples for high temperature measurement

    NASA Astrophysics Data System (ADS)

    Kreider, Kenneth G.

    1989-05-01

    Thin film thermocouples have unique capabilities for measuring surface temperatures at high temperatures (above 800 K) under harsh conditions. Their low mass, approximately 2 x 10(-5) g/mm permits very rapid response and very little disturbance of heat transfer to the surface being measured. This has led to applications inside gas turbine engines and diesel engines measuring the surface temperature of first stage turbine blades and vanes and ceramic liners in diesel cylinders. The most successful high temperature (up to 1300 K) thin film thermocouples are sputter deposited from platinum and platinum-10 percent rhodium targets although results using base metal alloys, gold, and platinel will also be presented. The fabrication techniques used to form the thermocouples, approaches used to solve the high temperature insulation and adherence problems, current applications, and test results using the thin film thermocouples are reviewed. In addition a discussion will be presented on the current problems and future trends related to applications of thin film thermocouples at higher temperatures up to 1900 K.

  7. US polycrystalline thin film solar cells program

    SciTech Connect

    Ullal, H.S.; Zweibel, K.; Mitchell, R.L. )

    1989-11-01

    The Polycrystalline Thin Film Solar Cells Program, part of the United States National Photovoltaic Program, performs R D on copper indium diselenide and cadmium telluride thin films. The objective of the Program is to support research to develop cells and modules that meet the US Department of Energy's long-term goals by achieving high efficiencies (15%-20%), low-cost ($50/m{sup 2}), and long-time reliability (30 years). The importance of work in this area is due to the fact that the polycrystalline thin-film CuInSe{sub 2} and CdTe solar cells and modules have made rapid advances. They have become the leading thin films for PV in terms of efficiency and stability. The US Department of Energy has increased its funding through an initiative through the Solar Energy Research Institute in CuInSe{sub 2} and CdTe with subcontracts to start in Spring 1990. 23 refs., 5 figs.

  8. New techniques for producing thin boron films

    SciTech Connect

    Thomas, G.E.

    1988-01-01

    A review will be presented of methods for producing thin boron films using an electron gun. Previous papers have had the problem of spattering of the boron source during the evaporation. Methods for reducing this problem will also be presented. 12 refs., 4 figs.

  9. Electromagnetic scattering by a straight thin wire

    NASA Technical Reports Server (NTRS)

    Shamansky, Harry T.; Dominek, Allen K.; Peters, Leon, Jr.

    1989-01-01

    The traveling-wave energy, which multiply diffracts on a straight thin wire, is represented as a sum of terms, each with a distinct physical meaning, that can be individually examined in the time domain. Expressions for each scattering mechanism on a straight thin wire are cast in the form of four basic electromagnetic wave concepts: diffraction, attachment, launch, and reflection. Using the basic mechanisms from P. Ya. Ufimtsev (1962), each of the scattering mechanisms is included into the total scattered field for the straight thin wire. Scattering as a function of angle and frequency is then compared to the moment-method solution. These analytic expressions are then extended to a lossy wire with a simple approximate modification using the propagation velocity on the wire as derived from the Sommerfeld wave on a straight lossy wire. Both the perfectly conducting and lossy wire solutions are compared to moment-method results, and excellent agreement is found. As is common with asymptotic solutions, when the electrical length of wire is smaller than 0.2 lambda the results lose accuracy. The expressions modified to approximate the scattering for the lossy thin wire yield excellent agreement even for lossy wires where the wire radius is on the order of skin depth.

  10. FDTD modeling of thin impedance sheets

    NASA Technical Reports Server (NTRS)

    Luebbers, Raymond J.; Kunz, Karl S.

    1991-01-01

    Thin sheets of resistive or dielectric material are commonly encountered in radar cross section calculations. Analysis of such sheets is simplified by using sheet impedances. In this paper it is shown that sheet impedances can be modeled easily and accurately using Finite Difference Time Domain (FDTD) methods.

  11. SPINK, A Thin Elements Spin Tracking Code

    SciTech Connect

    Luccio, Alfredo U.

    2009-08-04

    Spink is a spin tracking code for spin polarized particles. The code tracks both trajectories in 3D and spin. It works using thick element modeling from MAD and thin element modeling based on the BMT equation to track spin. The code is written in Fortran and typically runs on a Linux platform, either sequentially or MPI-parallel.

  12. Thick Slice and Thin Slice Teaching Evaluations

    ERIC Educational Resources Information Center

    Tom, Gail; Tong, Stephanie Tom; Hesse, Charles

    2010-01-01

    Student-based teaching evaluations are an integral component to institutions of higher education. Previous work on student-based teaching evaluations suggest that evaluations of instructors based upon "thin slice" 30-s video clips of them in the classroom correlate strongly with their end of the term "thick slice" student evaluations. This study's…

  13. Microwave-enhanced thin-film deposition

    NASA Technical Reports Server (NTRS)

    Chitre, S.

    1984-01-01

    The deposition of semiconducting and insulating thin films at low temperatures using microwave technology was explored. The method of plasma formations, selection of a power source, the design of the microwave plasma cavity, the microwave circuitry, impedance matching, plasma diagnostics, the deposition chamber and the vacuum system were studied.

  14. Process development of thin strip steel casting

    SciTech Connect

    Sussman, R.C.; Williams, R.S.

    1990-12-01

    An important new frontier is being opened in steel processing with the emergence of thin strip casting. Casting steel directly to thin strip has enormous benefits in energy savings by potentially eliminating the need for hot reduction in a hot strip mill. This has been the driving force for numerous current research efforts into the direct strip casting of steel. The US Department of Energy initiated a program to evaluate the development of thin strip casting in the steel industry. In earlier phases of this program, planar flow casting on an experimental caster was studied by a team of engineers from Westinghouse Electric corporation and Armco Inc. A subsequent research program was designed as a fundamental and developmental study of both planar and melt overflow casting processes. This study was arranged as several separate and distinct tasks which were often completed by different teams of researchers. An early task was to design and build a water model to study fluid flow through different designs of planar flow casting nozzles. Another important task was mathematically modeling of melt overflow casting process. A mathematical solidification model for the formation of the strip in the melt overflow process was written. A study of the material and conditioning of casting substrates was made on the small wheel caster using the melt overflow casting process. This report discusses work on the development of thin steel casting.

  15. An Extension of Thin Film Optics

    NASA Astrophysics Data System (ADS)

    Apell, P.

    1985-10-01

    The classical McIntyre formula for p-polarized light incident on a thin film on a substrate is extended in general terms to include a realistic description of the interfaces and the possible excitation of plasma waves in the film. An earlier extension is critized and criteria are given for when the classical result is applicable.

  16. Thin films, asphaltenes, and reservoir wettability

    SciTech Connect

    Kaminsky, R.; Bergeron, V.; Radke, C.J. |

    1993-04-01

    Reservoir wettability impacts the success of oil recovery by waterflooding and other methods. To understand wettability and its alteration, thin-film forces in solid-aqueous-oil systems must be elucidated. Upon rupture of thick aqueous films separating the oil and rock phases, asphaltene components in the crude oil adsorb irreversibly on the solid surface, changing it from water-wet to oil-wet. Conditions of wettability alteration can be found by performing adhesion tests, in which an oil droplet is brought into contact with a solid surface. Exceeding a critical capillary pressure destabilizes the film, causing spontaneous film rupture to a molecularly adsorbed layer and oil adhesion accompanied by pinning at the three-phase contact line. The authors conduct adhesion experiments similar to those of Buckley and Morrow and simultaneously examine the state of the underlying thin film using optical microscopy and microinterferometry. Aqueous thin films between an asphaltic Orcutt crude oil and glass surfaces are studied as a function of aqueous pH and salinity. For the first time, they prove experimentally that strongly water-wet to strongly oil-wet wettability alteration and contact-angle pinning occur when thick aqueous films thin to molecularly adsorbed films and when the oil phase contains asphaltene molecules.

  17. Semiconductor cooling by thin-film thermocouples

    NASA Technical Reports Server (NTRS)

    Tick, P. A.; Vilcans, J.

    1970-01-01

    Thin-film, metal alloy thermocouple junctions do not rectify, change circuit impedance only slightly, and require very little increase in space. Although they are less efficient cooling devices than semiconductor junctions, they may be applied to assist conventional cooling techniques for electronic devices.

  18. Analysis of a Thin Optical Lens Model

    ERIC Educational Resources Information Center

    Ivchenko, Vladimir V.

    2011-01-01

    In this article a thin optical lens model is considered. It is shown that the limits of its applicability are determined not only by the ratio between the thickness of the lens and the modules of the radii of curvature, but above all its geometric type. We have derived the analytical criteria for the applicability of the model for different types…

  19. Refracting boundaries in thin film glass lightguides

    NASA Astrophysics Data System (ADS)

    Turner, A. F.; Browning, S. D.

    1980-02-01

    The paper describes experimental studies of refraction at a straightline boundary between evaporated glass lightguides and evaporated thin film overlays of SbO3 with index 2.10. Attention is given to sample preparation, measurement procedures, and computations. It is noted that Snell's law gives the total change of mode indices on each side of the boundary are used.

  20. Bending of beams of thin sections

    NASA Technical Reports Server (NTRS)

    Huber, Maximilian T

    1936-01-01

    The tendency toward economy of material and lightness of structure has long since led to the increased application of beams having large ratios of moment of area W to cross-sectional area F. This paper tries to provide an answer to how thin the beams can be.

  1. US Polycrystalline Thin Film Solar Cells Program

    NASA Astrophysics Data System (ADS)

    Ullal, Harin S.; Zweibel, Kenneth; Mitchell, Richard L.

    1989-11-01

    The Polycrystalline Thin Film Solar Cells Program, part of the United States National Photovoltaic Program, performs R and D on copper indium diselenide and cadmium telluride thin films. The objective of the program is to support research to develop cells and modules that meet the U.S. Department of Energy's long-term goals by achieving high efficiencies (15 to 20 percent), low-cost ($50/m(sup 2)), and long-time reliability (30 years). The importance of work in this area is due to the fact that the polycrystalline thin-film CuInSe2 and CdTe solar cells and modules have made rapid advances. They have become the leading thin films for PV in terms of efficiency and stability. The U.S. Department of Energy has increased its funding through an initiative through the Solar Energy Research Institute in CuInSe2 and CdTe with subcontracts to start in spring 1990.

  2. Thin film hydrous metal oxide catalysts

    DOEpatents

    Dosch, Robert G.; Stephens, Howard P.

    1995-01-01

    Thin film (<100 nm) hydrous metal oxide catalysts are prepared by 1) synthesis of a hydrous metal oxide, 2) deposition of the hydrous metal oxide upon an inert support surface, 3) ion exchange with catalytically active metals, and 4) activating the hydrous metal oxide catalysts.

  3. Flexoelectricity in barium strontium titanate thin film

    SciTech Connect

    Kwon, Seol Ryung; Huang, Wenbin; Yuan, Fuh-Gwo; Jiang, Xiaoning; Shu, Longlong; Maria, Jon-Paul

    2014-10-06

    Flexoelectricity, the linear coupling between the strain gradient and the induced electric polarization, has been intensively studied as an alternative to piezoelectricity. Especially, it is of interest to develop flexoelectric devices on micro/nano scales due to the inherent scaling effect of flexoelectric effect. Ba{sub 0.7}Sr{sub 0.3}TiO{sub 3} thin film with a thickness of 130 nm was fabricated on a silicon wafer using a RF magnetron sputtering process. The flexoelectric coefficients of the prepared thin films were determined experimentally. It was revealed that the thin films possessed a transverse flexoelectric coefficient of 24.5 μC/m at Curie temperature (∼28 °C) and 17.44 μC/m at 41 °C. The measured flexoelectric coefficients are comparable to that of bulk BST ceramics, which are reported to be 10–100 μC/m. This result suggests that the flexoelectric thin film structures can be effectively used for micro/nano-sensing devices.

  4. NAA thinning of ‘W. Murcott’

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study was conducted to determine if NAA thinning may be useful for managing cropload in Florida ‘W Murcott’. Trials were conducted in two groves of ages 4 and 6 years. NAA was applied on 13 May, 2010, when fruitlets averaged 10-12 mm in diameter. A randomized complete block design was used, ...

  5. UV absorption control of thin film growth

    DOEpatents

    Biefeld, Robert M.; Hebner, Gregory A.; Killeen, Kevin P.; Zuhoski, Steven P.

    1991-01-01

    A system for monitoring and controlling the rate of growth of thin films in an atmosphere of reactant gases measures the UV absorbance of the atmosphere and calculates the partial pressure of the gases. The flow of reactant gases is controlled in response to the partial pressure.

  6. Method of producing thin cellulose nitrate film

    DOEpatents

    Lupica, S.B.

    1975-12-23

    An improved method for forming a thin nitrocellulose film of reproducible thickness is described. The film is a cellulose nitrate film, 10 to 20 microns in thickness, cast from a solution of cellulose nitrate in tetrahydrofuran, said solution containing from 7 to 15 percent, by weight, of dioctyl phthalate, said cellulose nitrate having a nitrogen content of from 10 to 13 percent.

  7. Thin-Film Solid Oxide Fuel Cells

    NASA Technical Reports Server (NTRS)

    Chen, Xin; Wu, Nai-Juan; Ignatiev, Alex

    2009-01-01

    The development of thin-film solid oxide fuel cells (TFSOFCs) and a method of fabricating them have progressed to the prototype stage. This can result in the reduction of mass, volume, and the cost of materials for a given power level.

  8. Strong field electrodynamics of a thin foil

    SciTech Connect

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

    2013-12-15

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

  9. Detecting Psychopathy from Thin Slices of Behavior

    ERIC Educational Resources Information Center

    Fowler, Katherine A.; Lilienfeld, Scott O.; Patrick, Christopher J.

    2009-01-01

    This study is the first to demonstrate that features of psychopathy can be reliably and validly detected by lay raters from "thin slices" (i.e., small samples) of behavior. Brief excerpts (5 s, 10 s, and 20 s) from interviews with 96 maximum-security inmates were presented in video or audio form or in both modalities combined. Forty raters used…

  10. Rechargeable Thin-film Lithium Batteries

    DOE R&D Accomplishments Database

    Bates, J. B.; Gruzalski, G. R.; Dudney, N. J.; Luck, C. F.; Yu, Xiaohua

    1993-08-01

    Rechargeable thin film batteries consisting of lithium metal anodes, an amorphous inorganic electrolyte, and cathodes of lithium intercalation compounds have recently been developed. The batteries, which are typically less than 6 {mu}m thick, can be fabricated to any specified size, large or small, onto a variety of substrates including ceramics, semiconductors, and plastics. The cells that have been investigated include Li TiS{sub 2}, Li V{sub 2}O{sub 5}, and Li Li{sub x}Mn{sub 2}O{sub 4}, with open circuit voltages at full charge of about 2.5, 3.6, and 4.2, respectively. The development of these batteries would not have been possible without the discovery of a new thin film lithium electrolyte, lithium phosphorus oxynitride, that is stable in contact with metallic lithium at these potentials. Deposited by rf magnetron sputtering of Li{sub 3}PO{sub 4} in N{sub 2}, this material has a typical composition of Li{sub 2.9}PO{sub 3.3}N{sub 0.46} and a conductivity at 25{degrees}C of 2 {mu}S/cm. The maximum practical current density obtained from the thin film cells is limited to about 100 {mu}A/cm{sup 2} due to a low diffusivity of Li{sup +} ions in the cathodes. In this work, the authors present a short review of their work on rechargeable thin film lithium batteries.

  11. Thin transparent films formed from powdered glass

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Glass film less than five mils thick is formed from powdered glass dispersed in an organic liquid, deposited on a substrate, and fused into place. The thin films can be cut and shaped for contact lenses, optical filters and insulating layers.

  12. Thinned Mature Deciduous Forest Silvopastures for Appalachia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Little information is available on effective management and utilization of silvopastures developed from the ubiquitous mature woodlots which comprise 40-50% of small Appalachian farm acreage. We thinned a white oak dominated mature second growth forested area establishing two 0.5 ha, eight-paddock,...

  13. Thin-Slice Perception Develops Slowly

    ERIC Educational Resources Information Center

    Balas, Benjamin; Kanwisher, Nancy; Saxe, Rebecca

    2012-01-01

    Body language and facial gesture provide sufficient visual information to support high-level social inferences from "thin slices" of behavior. Given short movies of nonverbal behavior, adults make reliable judgments in a large number of tasks. Here we find that the high precision of adults' nonverbal social perception depends on the slow…

  14. Thin Layer Chromatography (TLC) of Chlorophyll Pigments.

    ERIC Educational Resources Information Center

    Foote, Jerry

    1984-01-01

    Background information, list of materials needed, procedures used, and discussion of typical results are provided for an experiment on the thin layer chromatography of chlorophyll pigments. The experiment works well in high school, since the chemicals used are the same as those used in paper chromatography of plant pigments. (JN)

  15. Applications of Direct-Print Imaging with Thin-Sections.

    ERIC Educational Resources Information Center

    Nuhfer, E. B.; Vinopal, R. J.

    1979-01-01

    Describes a process by which prints are produced using thin sections as negatives in a photographic enlarger. Design of a thin section holder, exposure times for common rock types, and several sample illustrations are provided. (Author/MA)

  16. An Electrochemical Experiment Using an Optically Transparent Thin Layer Electrode

    ERIC Educational Resources Information Center

    DeAngelis, Thomas P.; Heineman, William R.

    1976-01-01

    Describes a unified experiment in which an optically transparent thin layer electrode is used to illustrate the techniques of thin layer electrochemistry, cyclic voltammetry, controlled potential coulometry, and spectroelectrochemistry. (MLH)

  17. Flexible cadmium telluride thin films grown on electron-beam-irradiated graphene/thin glass substrates

    SciTech Connect

    Seo, Won-Oh; Kim, Jihyun; Koo, Yong Hwan; Kim, Byungnam; Lee, Byung Cheol; Kim, Donghwan

    2014-08-25

    We demonstrate the close-spaced sublimation growth of polycrystalline cadmium telluride (CdTe) thin films on a flexible graphene electrode/thin glass substrate structure. Prior to the growth of CdTe films, chemical-vapor-deposited graphene was transferred onto a flexible glass substrate and subjected to electron-beam irradiation at an energy of 0.2 MeV in order to intentionally introduce the defects into it in a controlled manner. Micro-Raman spectroscopy and sheet resistance measurements were employed to monitor the damage and disorder in the electron-beam irradiated graphene layers. The morphology and optical properties of the CdTe thin films deposited on a graphene/flexible glass substrate were systematically characterized. The integration of the defective graphene layers with a flexible glass substrate can be a useful platform to grow various thin-film structures for flexible electronic and optoelectronic devices.

  18. X-Ray Standing Waves in Thin Crystals:. Probing the Polarity of Thin Epitaxial Films

    NASA Astrophysics Data System (ADS)

    Kazimirov, Alexander; Zegenhagen, Jörg; Lee, Tien-Lin; Bedzyk, Michael

    2013-01-01

    In thin crystals, an X-ray standing wave field is generated by the interference between the strong incident wave and the weak Bragg diffracted X-ray wave. Though the spatial modulation of the interference field is greatly reduced, the XSW method retains the same structural sensitivity as in thick perfect crystals diffracting dynamically. Because the diffraction curve from a thin crystal is broad, the XSW technique is much less sensitive to lattice imperfections. As examples, we demonstrate in this chapter how this technique can be applied to determine the "as-grown" and "externally switched" polarity in epitaxial thin films. With modern SR sources, the standing wave in an ultra-thin film of only 25 unit cells can be generated and utilized for precise structural investigation.

  19. Layer Thinning in Freely-Suspended Thin Liquid Films of a Symmetric Liquid Crystal Dimer

    NASA Astrophysics Data System (ADS)

    Pardaev, Shokir; Parsouzi, Zeinab; Gleeson, James; Jakli, Antal; Sprunt, Samuel

    We report optical reflectivity and dynamic light scattering (DLS) studies on freely suspended smectic films of a symmetric liquid crystal dimer, which exhibits the phase sequence isotropic--nematic--twist-bend nematic--smectic in cooling. In sufficiently thin films the reflectivity R is expected to scale as the square of the number of smectic layers (N2) while the frequency f of underdamped layer fluctuations scales as N - 1 / 2. On heating thin films drawn in the smectic phase, we observe a sequence of layer thinning transitions, with R and f following the expected scaling relations, provided the stepwise melting involves double rather than single layers. We will describe a model to explain the unusual layer thinning process. We thank M. G. Tamba and G. Mehl for providing the liquid crystal compound: NSF grant DMR-1307674.

  20. Characteristics of heat transfer fouling of thin stillage using model thin stillage and evaporator concentrates

    NASA Astrophysics Data System (ADS)

    Challa, Ravi Kumar

    The US fuel ethanol demand was 50.3 billion liters (13.3 billion gallons) in 2012. Corn ethanol was produced primarily by dry grind process. Heat transfer equipment fouling occurs during corn ethanol production and increases the operating expenses of ethanol plants. Following ethanol distillation, unfermentables are centrifuged to separate solids as wet grains and liquid fraction as thin stillage. Evaporator fouling occurs during thin stillage concentration to syrup and decreases evaporator performance. Evaporators need to be shutdown to clean the deposits from the evaporator surfaces. Scheduled and unscheduled evaporator shutdowns decrease process throughput and results in production losses. This research were aimed at investigating thin stillage fouling characteristics using an annular probe at conditions similar to an evaporator in a corn ethanol production plant. Fouling characteristics of commercial thin stillage and model thin stillage were studied as a function of bulk fluid temperature and heat transfer surface temperature. Experiments were conducted by circulating thin stillage or carbohydrate mixtures in a loop through the test section which consisted of an annular fouling probe while maintaining a constant heat flux by electrical heating and fluid flow rate. The change in fouling resistance with time was measured. Fouling curves obtained for thin stillage and concentrated thin stillage were linear with time but no induction periods were observed. Fouling rates for concentrated thin stillage were higher compared to commercial thin stillage due to the increase in solid concentration. Fouling rates for oil skimmed and unskimmed concentrated thin stillage were similar but lower than concentrated thin stillage at 10% solids concentration. Addition of post fermentation corn oil to commercial thin stillage at 0.5% increments increased the fouling rates up to 1% concentration but decreased at 1.5%. As thin stillage is composed of carbohydrates, protein, lipid

  1. Hydrogenated nanocrystalline silicon germanium thin films

    NASA Astrophysics Data System (ADS)

    Yusoff, A. R. M.; Syahrul, M. N.; Henkel, K.

    2007-08-01

    Hydrogenated nanocrystalline silicon germanium thin films (nc-SiGe:H) is an interesting alternative material to replace hydrogenated nanocrystalline silicon (nc-Si:H) as the narrow bandgap absorber in an a-Si/a-SiGe/nc-SiGe(nc-Si) triple-junction solar cell due to its higher optical absorption in the wavelength range of interest. In this paper, we present results of optical, structural investigations and electrical characterization of nc-SiGe:H thin films made by hot-wire chemical vapor deposition (HWCVD) with a coil-shaped tungsten filament and with a disilane/germane/hydrogen gas mixture. The optical band gaps of a-SiGe:H and nc-SiGe:H thin-films, which are deposited with the same disilane/germane/hydrogen gas mixture ratio of 3.4:1.7:7, are about 1.58 eV and 2.1 eV, respectively. The nc-SiGe:H thin film exhibits a larger optical absorption coefficient of about 2-4 in the 600-900 nm range when compared to nc-Si:H thin film. Therefore, a thinner nc-SiGe:H layer of sim500 nm thickness may be sufficient for the narrow bandgap absorber in an a-Si based multiple-junction solar cell. We enhanced the transport properties as measured by the photoconductivity frequency mixing technique. These improved alloys do not necessarily show an improvement in the degree of structural heterogeneity on the nanometer scale as measured by small-angle X-ray scattering. Decreasing both the filament temperature and substrate temperature produced a film with relatively low structural heterogeneity while photoluminescence showed an order of magnitude increase in defect density for a similar change in the process.

  2. Growth Induced Magnetic Anisotropy in Crystalline and Amorphous Thin Films

    SciTech Connect

    Hellman, Frances

    1998-10-03

    OAK B204 Growth Induced Magnetic Anisotropy in Crystalline and Amorphous Thin Films. The work in the past 6 months has involved three areas of magnetic thin films: (1) amorphous rare earth-transition metal alloys, (2) epitaxial Co-Pt and hTi-Pt alloy thin films, and (3) collaborative work on heat capacity measurements of magnetic thin films, including nanoparticles and CMR materials.

  3. Niobium Thin Film Characterization for Thin Film Technology Used in Superconducting Radiofrequency Cavities

    NASA Astrophysics Data System (ADS)

    Dai, Yishu; Valente-Feliciano, Anne-Marie

    2015-10-01

    Superconducting RadioFrequency (SRF) penetrates about 40-100 nm of the top surface, making thin film technology possible in producing superconducting cavities. Thin film is based on the deposition of a thin Nb layer on top of a good thermal conducting material such as Al or Cu. Thin film allows for better control of the surface and has negligible response to the Earth's magnetic field, eliminating the need for magnetic shielding of the cavities. Thin film superconductivity depends heavily on coating process conditions, involving controllable parameters such as crystal plane orientation, coating temperature, and ion energy. MgO and Al2O3 substrates are used because they offer very smooth surfaces, ideal for studying film growth. Atomic Force Microscopy is used to characterize surface's morphology. It is evident that a lower nucleation energy and a long coating time increases the film quality in the r-plane sapphire crystal orientation. The quality of the film increases with thickness. Nb films coated on r-plane, grow along the (001) plane and yield a much higher RRR compared to the films grown on a- and c-planes. This information allows for further improvement on the research process for thin film technology used in superconducting cavities for the particle accelerators. National Science Foundation, Department of Energy, Jefferson Lab, Old Dominion University.

  4. Solid-state thin-film supercapacitor with ruthenium oxide and solid electrolyte thin films

    NASA Astrophysics Data System (ADS)

    Yoon, Y. S.; Cho, W. I.; Lim, J. H.; Choi, D. J.

    Direct current reactive sputtering deposition of ruthenium oxide thin films (bottom and top electrodes) at 400°C are performed to produce a solid-state thin-film supercapacitor (TFSC). The supercapacitor has a cell structure of RuO 2/Li 2.94PO 2.37N 0.75 (Lipon)/RuO 2/Pt. Radio frequency, reactive sputtering deposition of an Li 2.94PO 2.37N 0.75 electrolyte film is performed on the bottom RuO 2 film at room temperature to separate the bottom and top RuO 2 electrodes electrically. The stoichiometry of the RuO 2 thin film is investigated by Rutherford back-scattering spectrometry (RBS). X-ray diffraction (XRD) shows that the as-deposited RuO 2 thin film is an amorphous phase. Scanning electron microscopy (SEM) measurements reveal that the RuO 2/Lipon/RuO 2 hetero-interfaces have no inter-diffusion problems. Charge-discharge measurements with constant current at room temperature clearly reveal typical supercapacitor behaviour for a RuO 2/Lipon/RuO 2/Pt cell structure. Since the electrolyte thin film has low ionic mobility, the capacity and cycle performance are inferior to those of a bulk type of supercapacitor. These results indicate that a high performance, TFSC can be fabricated by a solid electrolyte thin film with high ionic conductivity.

  5. Growth induced magnetic anisotropy in crystalline and amorphous thin films

    SciTech Connect

    Hellman, F.

    1998-07-20

    The work in the past 6 months has involved three areas of magnetic thin films: (1) amorphous rare earth-transition metal alloys, (2) epitaxial Co-Pt and Ni-Pt alloy thin films, and (3) collaborative work on heat capacity measurements of magnetic thin films, including nanoparticles and CMR materials. A brief summary of work done in each area is given.

  6. Studies and issues of thin-GaN LED process

    NASA Astrophysics Data System (ADS)

    Chen, P. H.; Lin, C. L.; Lin, Y. H.; Chou, P. K.; Liu, C. Y.

    2007-09-01

    A newly developed thin-GaN LED structure has shown great advantages over traditional LED schemes in the lighting efficiency performance. Yet, in the fabrication process of thin-GaN LED chip, several processes still remain to be optimized. In this paper, the process issues of the promising thin-GaN LED chip will be discussed.

  7. A Procedure for Thinning the Schedule of Time-Out

    ERIC Educational Resources Information Center

    Donaldson, Jeanne M.; Vollmer, Timothy R.

    2012-01-01

    Few studies have evaluated ways to thin punishment schedules. The purpose of this study was to examine the effects of using variable ratio (VR) schedules to thin the time-out schedule gradually. Warnings were used in some conditions to assist potentially with schedule thinning, but this analysis was limited. Participants were 3 young students who…

  8. 7 CFR 29.2663 - Thin Leaf (C Group).

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ..., pale color intensity, narrow, 70 percent uniform, and 30 percent injury tolerance. C5L Low Light-brown... that are thin in body. Grades Grade names and specifications C1L Choice Light-brown Thin Leaf. Thin, ripe, firm, oily, semielastic, normal strength, bright finish, deep color intensity, normal width,...

  9. 7 CFR 29.2663 - Thin Leaf (C Group).

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ..., pale color intensity, narrow, 70 percent uniform, and 30 percent injury tolerance. C5L Low Light-brown... that are thin in body. Grades Grade names and specifications C1L Choice Light-brown Thin Leaf. Thin, ripe, firm, oily, semielastic, normal strength, bright finish, deep color intensity, normal width,...

  10. 7 CFR 29.2663 - Thin Leaf (C Group).

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ..., pale color intensity, narrow, 70 percent uniform, and 30 percent injury tolerance. C5L Low Light-brown... that are thin in body. Grades Grade names and specifications C1L Choice Light-brown Thin Leaf. Thin, ripe, firm, oily, semielastic, normal strength, bright finish, deep color intensity, normal width,...

  11. Characteristics of heat transfer fouling of thin stillage using model thin stillage and evaporator concentrates

    NASA Astrophysics Data System (ADS)

    Challa, Ravi Kumar

    The US fuel ethanol demand was 50.3 billion liters (13.3 billion gallons) in 2012. Corn ethanol was produced primarily by dry grind process. Heat transfer equipment fouling occurs during corn ethanol production and increases the operating expenses of ethanol plants. Following ethanol distillation, unfermentables are centrifuged to separate solids as wet grains and liquid fraction as thin stillage. Evaporator fouling occurs during thin stillage concentration to syrup and decreases evaporator performance. Evaporators need to be shutdown to clean the deposits from the evaporator surfaces. Scheduled and unscheduled evaporator shutdowns decrease process throughput and results in production losses. This research were aimed at investigating thin stillage fouling characteristics using an annular probe at conditions similar to an evaporator in a corn ethanol production plant. Fouling characteristics of commercial thin stillage and model thin stillage were studied as a function of bulk fluid temperature and heat transfer surface temperature. Experiments were conducted by circulating thin stillage or carbohydrate mixtures in a loop through the test section which consisted of an annular fouling probe while maintaining a constant heat flux by electrical heating and fluid flow rate. The change in fouling resistance with time was measured. Fouling curves obtained for thin stillage and concentrated thin stillage were linear with time but no induction periods were observed. Fouling rates for concentrated thin stillage were higher compared to commercial thin stillage due to the increase in solid concentration. Fouling rates for oil skimmed and unskimmed concentrated thin stillage were similar but lower than concentrated thin stillage at 10% solids concentration. Addition of post fermentation corn oil to commercial thin stillage at 0.5% increments increased the fouling rates up to 1% concentration but decreased at 1.5%. As thin stillage is composed of carbohydrates, protein, lipid

  12. Microstructural characterization in nanocrystalline ceramic thin films

    NASA Astrophysics Data System (ADS)

    Kim, Hakkwan

    The primary objective of this research is to investigate the effects of process variables on microstructure in several fluoride and oxide thin films prepared by vapor deposition, in order to predict the properties and behaviors of nanocrystalline thin film materials. There are three distinct stages of this research. The first stage focuses on measuring of the porosity in polycrystalline thin films of a variety of fluorides as a function of the substrate temperature during deposition, and discussing the mechanism by which the porosity varies as a function of the process variables. We have measured the porosity in thin films of lithium fluoride (LiF), magnesium fluoride (MgF2), barium fluoride (BaF 2) and calcium fluoride (CaF2) using an atomic force microscope (AFM) and a quartz crystal thickness monitor. The porosity is very sensitive to the substrate temperature and decreases as the substrate temperature increases. Consistent behavior is observed among all of the materials in this study. The second stage is to understand the film microstructure including grain growth and texture development, because these factors are known to influence the behavior and stability of polycrystalline thin films. This study focuses on grain growth and texture development in polycrystalline lithium fluoride thin films using dark field (DF) transmission electron microscopy (TEM). It is demonstrated that we can isolate the size distribution of <111> surface normal grains from the overall size distribution, based on simple and plausible assumptions about the texture. The {111} texture formation and surface morphology were also observed by x-ray diffraction (XRD) and AFM, respectively. The grain size distributions become clearly bimodal as the annealing time increases, and we deduce that the short-time size distributions are also a sum of two overlapping peaks. The smaller grain-size peak in the distribution corresponds to the {111}-oriented grains which do not grow significantly, while

  13. Thin film bismuth iron oxides useful for piezoelectric devices

    DOEpatents

    Zeches, Robert J.; Martin, Lane W.; Ramesh, Ramamoorthy

    2016-05-31

    The present invention provides for a composition comprising a thin film of BiFeO.sub.3 having a thickness ranging from 20 nm to 300 nm, a first electrode in contact with the BiFeO.sub.3 thin film, and a second electrode in contact with the BiFeO.sub.3 thin film; wherein the first and second electrodes are in electrical communication. The composition is free or essentially free of lead (Pb). The BFO thin film is has the piezoelectric property of changing its volume and/or shape when an electric field is applied to the BFO thin film.

  14. Method of transferring a thin crystalline semiconductor layer

    DOEpatents

    Nastasi, Michael A.; Shao, Lin; Theodore, N. David

    2006-12-26

    A method for transferring a thin semiconductor layer from one substrate to another substrate involves depositing a thin epitaxial monocrystalline semiconductor layer on a substrate having surface contaminants. An interface that includes the contaminants is formed in between the deposited layer and the substrate. Hydrogen atoms are introduced into the structure and allowed to diffuse to the interface. Afterward, the thin semiconductor layer is bonded to a second substrate and the thin layer is separated away at the interface, which results in transferring the thin epitaxial semiconductor layer from one substrate to the other substrate.

  15. Domain switching of fatigued ferroelectric thin films

    SciTech Connect

    Tak Lim, Yun; Yeog Son, Jong E-mail: hoponpop@ulsan.ac.kr; Shin, Young-Han E-mail: hoponpop@ulsan.ac.kr

    2014-05-12

    We investigate the domain wall speed of a ferroelectric PbZr{sub 0.48}Ti{sub 0.52}O{sub 3} (PZT) thin film using an atomic force microscope incorporated with a mercury-probe system to control the degree of electrical fatigue. The depolarization field in the PZT thin film decreases with increasing the degree of electrical fatigue. We find that the wide-range activation field previously reported in ferroelectric domains result from the change of the depolarization field caused by the electrical fatigue. Domain wall speed exhibits universal behavior to the effective electric field (defined by an applied electric field minus the depolarization field), regardless of the degree of the electrical fatigue.

  16. Method for casting thin metal objects

    DOEpatents

    Pehrson, Brandon P; Moore, Alan F

    2015-04-14

    Provided herein are various embodiments of systems for casting thin metal plates and sheets. Typical embodiments include layers of mold cavities that are oriented vertically for casting the metal plates. In some embodiments, the mold cavities include a beveled edge such that the plates that are cast have a beveled edge. In some embodiments, the mold cavities are filled with a molten metal through an open horizontal edge of the cavity. In some embodiments, the mold cavities are filled through one or more vertical feed orifices. Further disclosed are methods for forming a thin cast metal plate or sheet where the thickness of the cast part is in a range from 0.005 inches to 0.2 inches, and the surface area of the cast part is in a range from 16 square inches to 144 square inches.

  17. Techniques for Connecting Superconducting Thin Films

    NASA Technical Reports Server (NTRS)

    Mester, John; Gwo, Dz-Hung

    2006-01-01

    Several improved techniques for connecting superconducting thin films on substrates have been developed. The techniques afford some versatility for tailoring the electronic and mechanical characteristics of junctions between superconductors in experimental electronic devices. The techniques are particularly useful for making superconducting or alternatively normally conductive junctions (e.g., Josephson junctions) between patterned superconducting thin films in order to exploit electron quantum-tunneling effects. The techniques are applicable to both low-Tc and high-Tc superconductors (where Tc represents the superconducting- transition temperature of a given material), offering different advantages for each. Most low-Tc superconductors are metallic, and heretofore, connections among them have been made by spot welding. Most high-Tc superconductors are nonmetallic and cannot be spot welded. These techniques offer alternatives to spot welding of most low-Tc superconductors and additional solutions to problems of connecting most high-Tc superconductors.

  18. Thin Nanoporous Metal-Insulator-Metal Membranes.

    PubMed

    Aramesh, Morteza; Djalalian-Assl, Amir; Yajadda, Mir Massoud Aghili; Prawer, Steven; Ostrikov, Kostya Ken

    2016-02-01

    Insulating nanoporous materials are promising platforms for soft-ionizing membranes; however, improvement in fabrication processes and the quality and high breakdown resistance of the thin insulator layers are needed for high integration and performance. Here, scalable fabrication of highly porous, thin, silicon dioxide membranes with controlled thickness is demonstrated using plasma-enhanced chemical-vapor-deposition. The fabricated membranes exhibit good insulating properties with a breakdown voltage of 1 × 10(7) V/cm. Our calculations suggest that the average electric field inside a nanopore of the membranes can be as high as 1 × 10(6) V/cm; sufficient for ionization of wide range of molecules. These metal-insulator-metal nanoporous arrays are promising for applications such soft ionizing membranes for mass spectroscopy. PMID:26846250

  19. Thin, nearly wireless adaptive optical device

    NASA Technical Reports Server (NTRS)

    Knowles, Gareth (Inventor); Hughes, Eli (Inventor)

    2008-01-01

    A thin, nearly wireless adaptive optical device capable of dynamically modulating the shape of a mirror in real time to compensate for atmospheric distortions and/or variations along an optical material is provided. The device includes an optical layer, a substrate, at least one electronic circuit layer with nearly wireless architecture, an array of actuators, power electronic switches, a reactive force element, and a digital controller. Actuators are aligned so that each axis of expansion and contraction intersects both substrate and reactive force element. Electronics layer with nearly wireless architecture, power electronic switches, and digital controller are provided within a thin-film substrate. The size and weight of the adaptive optical device is solely dominated by the size of the actuator elements rather than by the power distribution system.

  20. Thin, nearly wireless adaptive optical device

    NASA Technical Reports Server (NTRS)

    Knowles, Gareth (Inventor); Hughes, Eli (Inventor)

    2007-01-01

    A thin, nearly wireless adaptive optical device capable of dynamically modulating the shape of a mirror in real time to compensate for atmospheric distortions and/or variations along an optical material is provided. The device includes an optical layer, a substrate, at least one electronic circuit layer with nearly wireless architecture, an array of actuators, power electronic switches, a reactive force element, and a digital controller. Actuators are aligned so that each axis of expansion and contraction intersects both substrate and reactive force element. Electronics layer with nearly wireless architecture, power electronic switches, and digital controller are provided within a thin-film substrate. The size and weight of the adaptive optical device is solely dominated by the size of the actuator elements rather than by the power distribution system.

  1. Adhesion and friction of thin metal films

    NASA Technical Reports Server (NTRS)

    Buckley, D. H.

    1976-01-01

    Sliding friction experiments were conducted in vacuum with thin films of titanium, chromium, iron, and platinum sputter deposited on quartz or mica substrates. A single crystal hemispherically tipped gold slider was used in contact with the films at loads of 1.0 to 30.0 and at a sliding velocity of 0.7 mm/min at 23 C. Test results indicate that the friction coefficient is dependent on the adhesion of two interfaces, that between the film and its substrate and the slider and the film. There exists a relationship between the percent d bond character of metals in bulk and in thin film form and the friction coefficient. Oxygen can increase adhesive bonding of a metal film (platinum) to a substrate.

  2. Stability of patterns on thin curved surfaces

    NASA Astrophysics Data System (ADS)

    Nampoothiri, Sankaran

    2016-08-01

    We consider reaction-diffusion equations on a thin curved surface and obtain a set of effective reaction-diffusion (R-D) equations to O (ɛ2) , where ɛ is the surface thickness. We observe that the R-D systems on these curved surfaces can have space-dependent reaction kinetics. Further, we use linear stability analysis to study the Schnakenberg model on spherical and cylindrical geometries. The dependence of the steady state on the thickness is determined for both cases, and we find that a change in the thickness can stabilize the unstable modes, and vice versa. The combined effect of thickness and curvature can play an important role in the rearrangement of spatial patterns on thin curved surfaces.

  3. Polycrystalline thin films FY 1992 project report

    SciTech Connect

    Zweibel, K.

    1993-01-01

    This report summarizes the activities and results of the Polycrystalline Thin Film Project during FY 1992. The purpose of the DOE/NREL PV (photovoltaic) Program is to facilitate the development of PV that can be used on a large enough scale to produce a significant amount of energy in the US and worldwide. The PV technologies under the Polycrystalline Thin Film project are among the most exciting next-generation'' options for achieving this goal. Over the last 15 years, cell-level progress has been steady, with laboratory cell efficiencies reaching levels of 15 to 16%. This progress, combined with potentially inexpensive manufacturing methods, has attracted significant commercial interest from US and international companies. The NREL/DOE program is designed to support the efforts of US companies through cost-shared subcontracts (called government/industry partnerships'') that we manage and fund and through collaborative technology development work among industry, universities, and our laboratory.

  4. Stability of patterns on thin curved surfaces.

    PubMed

    Nampoothiri, Sankaran

    2016-08-01

    We consider reaction-diffusion equations on a thin curved surface and obtain a set of effective reaction-diffusion (R-D) equations to O(ε^{2}), where ε is the surface thickness. We observe that the R-D systems on these curved surfaces can have space-dependent reaction kinetics. Further, we use linear stability analysis to study the Schnakenberg model on spherical and cylindrical geometries. The dependence of the steady state on the thickness is determined for both cases, and we find that a change in the thickness can stabilize the unstable modes, and vice versa. The combined effect of thickness and curvature can play an important role in the rearrangement of spatial patterns on thin curved surfaces. PMID:27627331

  5. Nanoporous piezo- and ferroelectric thin films.

    PubMed

    Ferreira, Paula; Hou, Ru Z; Wu, Aiying; Willinger, Marc-Georg; Vilarinho, Paula M; Mosa, Jadra; Laberty-Robert, Christel; Boissière, Cédric; Grosso, David; Sanchez, Clément

    2012-02-01

    Nanoporous barium titanate and lead titanate thin films (∼100 nm calculated from ellipsometric data) are prepared starting from sol-gel solutions modified with a commercially available block-copolymer and evaporation-induced self-assembly methodology. The tuning of the thermal treatment followed by in situ ellipsometry allows the decomposition of the organic components and of the structuring agent leading to the formation of porous tetragonal crystalline perovskite structures as observed by XRD, HRTEM, SEM, and ellipsoporosimetry. Both nanoporous barium titanate and lead titanate thin films present local piezoelectric and ferroelectric behavior measured by piezoresponse force microscopy (PFM), being promising platforms for the preparation of the generation of new multifunctional systems. PMID:22206407

  6. Thin film strain gage development program

    NASA Technical Reports Server (NTRS)

    Grant, H. P.; Przybyszewski, J. S.; Anderson, W. L.; Claing, R. G.

    1983-01-01

    Sputtered thin-film dynamic strain gages of 2 millimeter (0.08 in) gage length and 10 micrometer (0.0004 in) thickness were fabricated on turbojet engine blades and tested in a simulated compressor environment. Four designs were developed, two for service to 600 K (600 F) and two for service to 900 K (1200 F). The program included a detailed study of guidelines for formulating strain-gage alloys to achieve superior dynamic and static gage performance. The tests included gage factor, fatigue, temperature cycling, spin to 100,000 G, and erosion. Since the installations are 30 times thinner than conventional wire strain gage installations, and any alteration of the aerodynamic, thermal, or structural performance of the blade is correspondingly reduced, dynamic strain measurement accuracy higher than that attained with conventional gages is expected. The low profile and good adherence of the thin film elements is expected to result in improved durability over conventional gage elements in engine tests.

  7. Spline Approximation of Thin Shell Dynamics

    NASA Technical Reports Server (NTRS)

    delRosario, R. C. H.; Smith, R. C.

    1996-01-01

    A spline-based method for approximating thin shell dynamics is presented here. While the method is developed in the context of the Donnell-Mushtari thin shell equations, it can be easily extended to the Byrne-Flugge-Lur'ye equations or other models for shells of revolution as warranted by applications. The primary requirements for the method include accuracy, flexibility and efficiency in smart material applications. To accomplish this, the method was designed to be flexible with regard to boundary conditions, material nonhomogeneities due to sensors and actuators, and inputs from smart material actuators such as piezoceramic patches. The accuracy of the method was also of primary concern, both to guarantee full resolution of structural dynamics and to facilitate the development of PDE-based controllers which ultimately require real-time implementation. Several numerical examples provide initial evidence demonstrating the efficacy of the method.

  8. Multiferroic oxide thin films and heterostructures

    SciTech Connect

    Lu, Chengliang E-mail: Tao.Wu@kaust.edu.sa; Hu, Weijin; Wu, Tom E-mail: Tao.Wu@kaust.edu.sa; Tian, Yufeng

    2015-06-15

    Multiferroic materials promise a tantalizing perspective of novel applications in next-generation electronic, memory, and energy harvesting technologies, and at the same time they also represent a grand scientific challenge on understanding complex solid state systems with strong correlations between multiple degrees of freedom. In this review, we highlight the opportunities and obstacles in growing multiferroic thin films with chemical and structural integrity and integrating them in functional devices. Besides the magnetoelectric effect, multiferroics exhibit excellent resistant switching and photovoltaic properties, and there are plenty opportunities for them to integrate with other ferromagnetic and superconducting materials. The challenges include, but not limited, defect-related leakage in thin films, weak magnetism, and poor control on interface coupling. Although our focuses are Bi-based perovskites and rare earth manganites, the insights are also applicable to other multiferroic materials. We will also review some examples of multiferroic applications in spintronics, memory, and photovoltaic devices.

  9. Thin sheets achieve optimal wrapping of liquids

    NASA Astrophysics Data System (ADS)

    Paulsen, Joseph; Démery, Vincent; Davidovitch, Benny; Santangelo, Christian; Russell, Thomas; Menon, Narayanan

    2015-03-01

    A liquid drop can wrap itself in a sheet using capillary forces [Py et al., PRL 98, 2007]. However, the efficiency of ``capillary origami'' at covering the surface of a drop is hampered by the mechanical cost of bending the sheet. Thinner sheets deform more readily by forming small-scale wrinkles and stress-focussing patterns, but it is unclear how coverage efficiency competes with mechanical cost as thickness is decreased, and what wrapping shapes will emerge. We place a thin (~ 100 nm) polymer film on a drop whose volume is gradually decreased so that the sheet covers an increasing fraction of its surface. The sheet exhibits a complex sequence of axisymmetric and polygonal partially- and fully- wrapped shapes. Remarkably, the progression appears independent of mechanical properties. The gross shape, which neglects small-scale features, is correctly predicted by a simple geometric approach wherein the exposed area is minimized. Thus, simply using a thin enough sheet results in maximal coverage.

  10. Induced electronic anisotropy in bismuth thin films

    SciTech Connect

    Liao, Albert D.; Yao, Mengliang; Opeil, Cyril; Katmis, Ferhat; Moodera, Jagadeesh S.; Li, Mingda; Tang, Shuang; Dresselhaus, Mildred S.

    2014-08-11

    We use magneto-resistance measurements to investigate the effect of texturing in polycrystalline bismuth thin films. Electrical current in bismuth films with texturing such that all grains are oriented with the trigonal axis normal to the film plane is found to flow in an isotropic manner. By contrast, bismuth films with no texture such that not all grains have the same crystallographic orientation exhibit anisotropic current flow, giving rise to preferential current flow pathways in each grain depending on its orientation. Extraction of the mobility and the phase coherence length in both types of films indicates that carrier scattering is not responsible for the observed anisotropic conduction. Evidence from control experiments on antimony thin films suggests that the anisotropy is a result of bismuth's large electron effective mass anisotropy.

  11. Method of casting silicon into thin sheets

    DOEpatents

    Sanjurjo, Angel; Rowcliffe, David J.; Bartlett, Robert W.

    1982-10-26

    Silicon (Si) is cast into thin shapes within a flat-bottomed graphite crucible by providing a melt of molten Si along with a relatively small amount of a molten salt, preferably NaF. The Si in the resulting melt forms a spherical pool which sinks into and is wetted by the molten salt. Under these conditions the Si will not react with any graphite to form SiC. The melt in the crucible is pressed to the desired thinness with a graphite tool at which point the tool is held until the mass in the crucible has been cooled to temperatures below the Si melting point, at which point the Si shape can be removed.

  12. Polycrystalline thin films FY 1992 project report

    SciTech Connect

    Zweibel, K.

    1993-01-01

    This report summarizes the activities and results of the Polycrystalline Thin Film Project during FY 1992. The purpose of the DOE/NREL PV (photovoltaic) Program is to facilitate the development of PV that can be used on a large enough scale to produce a significant amount of energy in the US and worldwide. The PV technologies under the Polycrystalline Thin Film project are among the most exciting ``next-generation`` options for achieving this goal. Over the last 15 years, cell-level progress has been steady, with laboratory cell efficiencies reaching levels of 15 to 16%. This progress, combined with potentially inexpensive manufacturing methods, has attracted significant commercial interest from US and international companies. The NREL/DOE program is designed to support the efforts of US companies through cost-shared subcontracts (called ``government/industry partnerships``) that we manage and fund and through collaborative technology development work among industry, universities, and our laboratory.

  13. Substrate heater for thin film deposition

    DOEpatents

    Foltyn, Steve R.

    1996-01-01

    A substrate heater for thin film deposition of metallic oxides upon a target substrate configured as a disk including means for supporting in a predetermined location a target substrate configured as a disk, means for rotating the target substrate within the support means, means for heating the target substrate within the support means, the heating means about the support means and including a pair of heating elements with one heater element situated on each side of the predetermined location for the target substrate, with one heater element defining an opening through which desired coating material can enter for thin film deposition and with the heating means including an opening slot through which the target substrate can be entered into the support means, and, optionally a means for thermal shielding of the heating means from surrounding environment is disclosed.

  14. Superconducting thin films on potassium tantalate substrates

    SciTech Connect

    Feenstra, R.; Boatner, L.A.

    1992-05-05

    This patent describes a composition for the lossless transmission of electrical current, it comprises: a superconducting thin film epitaxially deposited on a oriented surface of a single crystal KTa{sub 1{minus}z}Nb{sub 2}O{sub 3} substrate, where z is 0 to 1, wherein the superconducting thin film is selected from the group consisting of YBa{sub 2{minus}}Cu{sub 3}O{sub 7}, Y{sub 2}Ba{sub 4}Cu{sub 8}O{sub 20}, a compound wherein a trivalent rare earth element replaces yttrium in compound YBa{sub 2}Cu{sub 3}O{sub 7}, and a compound wherein scandium replaces yttrium in the compound YBa{sub 2}Cu{sub 3}O{sub 7}.

  15. Thin Silicon MEMS Contact-Stress Sensor

    SciTech Connect

    Kotovsky, J; Tooker, A; Horsley, D

    2010-03-22

    This thin, MEMS contact-stress (CS) sensor continuously and accurately measures time-varying, solid interface loads in embedded systems over tens of thousands of load cycles. Unlike all other interface load sensors, the CS sensor is extremely thin (< 150 {micro}m), provides accurate, high-speed measurements, and exhibits good stability over time with no loss of calibration with load cycling. The silicon CS sensor, 5 mm{sup 2} and 65 {micro}m thick, has piezoresistive traces doped within a load-sensitive diaphragm. The novel package utilizes several layers of flexible polyimide to mechanically and electrically isolate the sensor from the environment, transmit normal applied loads to the diaphragm, and maintain uniform thickness. The CS sensors have a highly linear output in the load range tested (0-2.4 MPa) with an average accuracy of {+-} 1.5%.

  16. Thin Magnetically Soft Wires for Magnetic Microsensors

    PubMed Central

    Zhukova, Valentina; Ipatov, Mihail; Zhukov, Arcady

    2009-01-01

    Recent advances in technology involving magnetic materials require development of novel advanced magnetic materials with improved magnetic and magneto-transport properties and with reduced dimensionality. Therefore magnetic materials with outstanding magnetic characteristics and reduced dimensionality have recently gained much attention. Among these magnetic materials a family of thin wires with reduced geometrical dimensions (of order of 1–30 μm in diameter) have gained importance within the last few years. These thin wires combine excellent soft magnetic properties (with coercivities up to 4 A/m) with attractive magneto-transport properties (Giant Magneto-impedance effect, GMI, Giant Magneto-resistance effect, GMR) and an unusual re-magnetization process in positive magnetostriction compositions exhibiting quite fast domain wall propagation. In this paper we overview the magnetic and magneto-transport properties of these microwires that make them suitable for microsensor applications. PMID:22291562

  17. The thinning of viscous liquid threads.

    NASA Astrophysics Data System (ADS)

    Castrejon-Pita, J. Rafael; Castrejon-Pita, Alfonso A.; Hutchings, Ian M.

    2012-11-01

    The thinning neck of dripping droplets is studied experimentally for viscous Newtonian fluids. High speed imaging is used to measure the minimum neck diameter in terms of the time τ to breakup. Mixtures of water and glycerol with viscosities ranging from 20 to 363 mPa s are used to model the Newtonian behavior. The results show the transition from potential to inertial-viscous regimes occurs at the predicted values of ~Oh2. Before this transition the neck contraction rate follows the inviscid scaling law ~τ 2 / 3 . After the transition, the neck thinning tends towards the linear viscous scaling law ~ τ . Project supported by the EPSRC-UK (EP/G029458/1) and Cambridge-KACST.

  18. Radiation effects on thin film solar cells

    SciTech Connect

    Gay, C.F.; Anspaugh, B.E.; Potter, R.R.; Tanner, D.P.

    1984-05-01

    A study has been undertaken to assess the effects of 1 MeV electron radiation on two types of thin film solar cells, thin-film silicon:hydrogen alloy (TFS) and copper indium diselenide (CIS). Using TFS devices with efficiencies between 8-9% AM 0 (9-10% AM 1.5), and CIS devices with efficiencies between 7-8% AM 0 (8-9% AM 1.5), the results show the devices are more stable to electron radiation than the typical crystalline silicon aerospace cells. In fact the CIS showed no degradation at all and with low temperature annealing the TFS could be restored to within 97% of initial power output.

  19. Impedance matched thin metamaterials make metals absorbing.

    PubMed

    Mattiucci, N; Bloemer, M J; Aközbek, N; D'Aguanno, G

    2013-01-01

    Metals are generally considered good reflectors over the entire electromagnetic spectrum up to their plasma frequency. Here we demonstrate an approach to tailor their absorbing characteristics based on the effective metamaterial properties of thin, periodic metallo-dielectric multilayers by exploiting a broadband, inherently non-resonant, surface impedance matching mechanism. Based on this mechanism, we design, fabricate and test omnidirectional, thin (<1 micron), polarization independent, extremely efficient absorbers (in principle being capable to reach A > 99%) over a frequency range spanning from the UV to the IR. Our approach opens new venues to design cost effective materials for many applications such as thermo-photovoltaic energy conversion devices, light harvesting for solar cells, flat panel display, infrared detectors, stray light reduction, stealth and others. PMID:24220284

  20. Generalized Ellipsometry on Ferromagnetic Sculptured Thin Films.

    NASA Astrophysics Data System (ADS)

    Schmidt, Daniel; Hofmann, Tino; Mok, Kah; Schmidt, Heidemarie; Skomski, Ralf; Schubert, Eva; Schubert, Mathias

    2011-03-01

    We present and discuss generalized ellipsometry and generalized vector-magneto-optic ellipsometry investigations on cobalt nanostructured thin films with slanted, highly-spatially coherent, columnar arrangement. The samples were prepared by glancing angle deposition. The thin films are highly transparent and reveal strong form-induced birefringence. We observe giant Kerr rotation in the visible spectral region, tunable by choice of the nanostructure geometry. Spatial magnetization orientation hysteresis and magnetization magnitude hysteresis properties are studied using a 3-dimensional Helmholtz coil arrangement allowing for arbitrary magnetic field direction at the sample position for field strengths up to 0.4 Tesla. Analysis of data obtained within this novel vector-magneto-optic setup reveals magnetization anisotropy of the Co slanted nanocolumns supported by mean-field theory modeling.

  1. Holographic NDT of thin titanium plate described

    NASA Astrophysics Data System (ADS)

    Yang, R.

    1986-01-01

    Holography is a technique for recording the amplitude and phase changes of an object on a photographic plate in the form of interference fringes. Because the holographic interference method can examine a component in the noncontact mode and is not bothered by complicated part shape or surface roughness, it has been widely used in nondestructive testing. In the rapidly developing aerospace industry, titanium and titanium alloy thin plates are used more and more but local delamination has been found in the production process of bonded titanium plates. Using ultrasonic methods, such defects are difficult to detect and large area delaminations with tightly closed edges can easily be missed. Other testing methods are also unsuccessful. A holographic method was developed for detecting defects in thin titanium plates and several high temperature alloy plates were tested. The testing equipment, methods and results are discussed.

  2. Electrostatic Discharge Effects on Thin Film Resistors

    NASA Technical Reports Server (NTRS)

    Sampson, Michael J.; Hull, Scott M.

    1999-01-01

    Recently, open circuit failures of individual elements in thin film resistor networks have been attributed to electrostatic discharge (ESD) effects. This paper will discuss the investigation that came to this conclusion and subsequent experimentation intended to characterize design factors that affect the sensitivity of resistor elements to ESD. The ESD testing was performed using the standard human body model simulation. Some of the design elements to be evaluated were: trace width, trace length (and thus width to length ratio), specific resistivity of the trace (ohms per square) and resistance value. However, once the experiments were in progress, it was realized that the ESD sensitivity of most of the complex patterns under evaluation was determined by other design and process factors such as trace shape and termination pad spacing. This paper includes pictorial examples of representative ESD failure sites, and provides some options for designing thin film resistors that are ESD resistant. The risks of ESD damage are assessed and handling precautions suggested.

  3. MISSE 5 Thin Films Space Exposure Experiment

    NASA Technical Reports Server (NTRS)

    Harvey, Gale A.; Kinard, William H.; Jones, James L.

    2007-01-01

    The Materials International Space Station Experiment (MISSE) is a set of space exposure experiments using the International Space Station (ISS) as the flight platform. MISSE 5 is a co-operative endeavor by NASA-LaRC, United Stated Naval Academy, Naval Center for Space Technology (NCST), NASA-GRC, NASA-MSFC, Boeing, AZ Technology, MURE, and Team Cooperative. The primary experiment is performance measurement and monitoring of high performance solar cells for U.S. Navy research and development. A secondary experiment is the telemetry of this data to ground stations. A third experiment is the measurement of low-Earth-orbit (LEO) low-Sun-exposure space effects on thin film materials. Thin films can provide extremely efficacious thermal control, designation, and propulsion functions in space to name a few applications. Solar ultraviolet radiation and atomic oxygen are major degradation mechanisms in LEO. This paper is an engineering report of the MISSE 5 thm films 13 months space exposure experiment.

  4. Hematite thin films: growth and characterization

    NASA Astrophysics Data System (ADS)

    Uribe, J. D.; Osorio, J.; Barrero, C. A.; Giratá, D.; Morales, A. L.; Devia, A.; Gómez, M. E.; Ramirez, J. G.; Gancedo, J. R.

    2006-04-01

    We have grown hematite (α Fe 2 O 3) thin films on stainless steel and (001)-silicon single-crystal substrates by RF magnetron sputtering process in argon atmosphere at substrate temperatures from 400 to 800°C. Conversion Electron Mössbauer (CEM) spectra of the sample grown on stainless steel at 400°C exhibit values for hyperfine parameter characteristic of bulk hematite phase in the weak ferromagnetic state. Also, the relative line intensity ratio suggests that the magnetization vector of the polycrystalline film is aligned preferentially parallel to the surface. The X-ray diffraction (XRD) pattern of the polycrystalline thin film grown on steel substrates also corresponds to α Fe 2 O 3. The samples were also analyzed by Atomic Force Microscopy (AFM), those grown on stainless steel reveal a morphology consisting of columnar grains with random orientation, given the inhomogeneity of the substrate surface.

  5. Hematite thin films: growth and characterization

    NASA Astrophysics Data System (ADS)

    Uribe, J. D.; Osorio, J.; Barrero, C. A.; Giratá, D.; Morales, A. L.; Devia, A.; Gómez, M. E.; Ramirez, J. G.; Gancedo, J. R.

    We have grown hematite (α - Fe 2 O 3) thin films on stainless steel and (001)-silicon single-crystal substrates by RF magnetron sputtering process in argon atmosphere at substrate temperatures from 400 to 800°C. Conversion Electron Mössbauer (CEM) spectra of the sample grown on stainless steel at 400°C exhibit values for hyperfine parameter characteristic of bulk hematite phase in the weak ferromagnetic state. Also, the relative line intensity ratio suggests that the magnetization vector of the polycrystalline film is aligned preferentially parallel to the surface. The X-ray diffraction (XRD) pattern of the polycrystalline thin film grown on steel substrates also corresponds to α - Fe 2O3. The samples were also analyzed by Atomic Force Microscopy (AFM), those grown on stainless steel reveal a morphology consisting of columnar grains with random orientation, given the inhomogeneity of the substrate surface.

  6. Impedance matched thin metamaterials make metals absorbing

    PubMed Central

    Mattiucci, N.; Bloemer, M. J.; Aközbek, N.; D'Aguanno, G.

    2013-01-01

    Metals are generally considered good reflectors over the entire electromagnetic spectrum up to their plasma frequency. Here we demonstrate an approach to tailor their absorbing characteristics based on the effective metamaterial properties of thin, periodic metallo-dielectric multilayers by exploiting a broadband, inherently non-resonant, surface impedance matching mechanism. Based on this mechanism, we design, fabricate and test omnidirectional, thin (<1 micron), polarization independent, extremely efficient absorbers (in principle being capable to reach A > 99%) over a frequency range spanning from the UV to the IR. Our approach opens new venues to design cost effective materials for many applications such as thermo-photovoltaic energy conversion devices, light harvesting for solar cells, flat panel display, infrared detectors, stray light reduction, stealth and others. PMID:24220284

  7. Thin-film forces in pseudoemulsion films

    SciTech Connect

    Bergeron, V.; Radke, C.J. |

    1991-06-01

    Use of foam for enhanced oil recovery (EOR) has shown recent success in steam-flooding field applications. Foam can also provide an effective barrier against gas coning in thin oil zones. Both of these applications stem from the unique mobility-control properties a stable foam possesses when it exists in porous media. Unfortunately, oil has a major destabilizing effect on foam. Therefore, it is important for EOR applications to understand how oil destroys foam. Studies all indicate that stabilization of the pseudoemulsion film is critical to maintain foam stability in the presence of oil. Hence, to aid in design of surfactant formulations for foam insensitivity to oil the authors pursue direct measurement of the thin-film or disjoining forces that stabilize pseudoemulsion films. Experimental procedures and preliminary results are described.

  8. Thin nearly wireless adaptive optical device

    NASA Technical Reports Server (NTRS)

    Knowles, Gareth J. (Inventor); Hughes, Eli (Inventor)

    2009-01-01

    A thin nearly wireless adaptive optical device capable of dynamically modulating the shape of a mirror in real time to compensate for atmospheric distortions and/or variations along an optical material is provided. The device includes an optical layer, a substrate, at least one electronic circuit layer with nearly wireless architecture, an array of actuators, power electronic switches, a reactive force element, and a digital controller. Actuators are aligned so that each axis of expansion and contraction intersects both substrate and reactive force element. Electronics layer with nearly wireless architecture, power electronic switches, and digital controller are provided within a thin-film substrate. The size and weight of the adaptive optical device is solely dominated by the size of the actuator elements rather than by the power distribution system.

  9. Rechargeable thin-film electrochemical generator

    DOEpatents

    Rouillard, Roger; Domroese, Michael K.; Hoffman, Joseph A.; Lindeman, David D.; Noel, Joseph-Robert-Gaetan; Radewald, Vern E.; Ranger, Michel; Sudano, Anthony; Trice, Jennifer L.; Turgeon, Thomas A.

    2000-09-15

    An improved electrochemical generator is disclosed. The electrochemical generator includes a thin-film electrochemical cell which is maintained in a state of compression through use of an internal or an external pressure apparatus. A thermal conductor, which is connected to at least one of the positive or negative contacts of the cell, conducts current into and out of the cell and also conducts thermal energy between the cell and thermally conductive, electrically resistive material disposed on a vessel wall adjacent the conductor. The thermally conductive, electrically resistive material may include an anodized coating or a thin sheet of a plastic, mineral-based material or conductive polymer material. The thermal conductor is fabricated to include a resilient portion which expands and contracts to maintain mechanical contact between the cell and the thermally conductive material in the presence of relative movement between the cell and the wall structure. The electrochemical generator may be disposed in a hermetically sealed housing.

  10. Thin film photovoltaic panel and method

    DOEpatents

    Ackerman, Bruce; Albright, Scot P.; Jordan, John F.

    1991-06-11

    A thin film photovoltaic panel includes a backcap for protecting the active components of the photovoltaic cells from adverse environmental elements. A spacing between the backcap and a top electrode layer is preferably filled with a desiccant to further reduce water vapor contamination of the environment surrounding the photovoltaic cells. The contamination of the spacing between the backcap and the cells may be further reduced by passing a selected gas through the spacing subsequent to sealing the backcap to the base of the photovoltaic panels, and once purged this spacing may be filled with an inert gas. The techniques of the present invention are preferably applied to thin film photovoltaic panels each formed from a plurality of photovoltaic cells arranged on a vitreous substrate. The stability of photovoltaic conversion efficiency remains relatively high during the life of the photovoltaic panel, and the cost of manufacturing highly efficient panels with such improved stability is significantly reduced.

  11. Temperature dependence of LRE-HRE-TM thin films

    NASA Astrophysics Data System (ADS)

    Li, Zuoyi; Cheng, Xiaomin; Lin, Gengqi; Li, Zhen; Huang, Zhixin; Jin, Fang; Wang, Xianran; Yang, Xiaofei

    2003-04-01

    Temperature dependence of the properties of RE-TM thin films is very important for MO recording. In this paper, we studied the temperature dependence of the magnetic and magneto-optical properties of the amorphous LRE-HRE-TM single layer thin films and LRE-HRE-TM/HRE-TM couple-bilayered thin films. For LRE-HRE-TM single layer thin films, the temperature dependence of the magnetization was investigated by using the mean field theory. The experimental and theoretical results matched very well. With the LRE substitution in HRE-TM thin film, the compensation temperature Tcomp decreased and the curie temperature Tc remained unchanged. Kerr rotation angle became larger and the saturation magnetization Ms at room temperature increased. For LRE-HRE-TM/HRE-TM couple-bilayered thin films, comparisons of the temperature dependences of the coercivities and Kerr rotation angles were made between isolated sublayers and couple-bilayered thin film.

  12. High energy high brightness thin disk laser

    NASA Astrophysics Data System (ADS)

    Nixon, Matthew D.; Cates, Michael C.

    2012-11-01

    Boeing has been developing solid state lasers for high energy applications since 2004 using Yb:YAG thin disk lasers as pioneered by A. Giesen1 and commercialized by Trumpf Laser GmbH.2 In this paper, we report results of our second generation design and status of a third generation we are currently developing, which will produce 35 kW and a beam quality <2.

  13. Flexible thin metal film thermal sensing system

    NASA Technical Reports Server (NTRS)

    Thomsen, Donald L. (Inventor)

    2010-01-01

    A flexible thin metal film thermal sensing system is provided. A self-metallized polymeric film has a polymeric film region and a metal surface disposed thereon. A layer of electrically-conductive metal is deposited directly onto the self-metallized polymeric film's metal surface. Coupled to at least one of the metal surface and the layer of electrically-conductive metal is a device/system for measuring an electrical characteristic associated therewith as an indication of temperature.

  14. Annealed CVD molybdenum thin film surface

    DOEpatents

    Carver, Gary E.; Seraphin, Bernhard O.

    1984-01-01

    Molybdenum thin films deposited by pyrolytic decomposition of Mo(CO).sub.6 attain, after anneal in a reducing atmosphere at temperatures greater than 700.degree. C., infrared reflectance values greater than reflectance of supersmooth bulk molybdenum. Black molybdenum films deposited under oxidizing conditions and annealed, when covered with an anti-reflecting coating, approach the ideal solar collector characteristic of visible light absorber and infrared energy reflector.

  15. Thin-film optical shutter. Final report

    SciTech Connect

    Matlow, S.L.

    1981-02-01

    A specific embodiment of macroconjugated macromolecules, the poly (p-phenylene)'s, has been chosen as the one most likely to meet all of the requirements of the Thin Film Optical Shutter project (TFOS). The reason for this choice is included. In order to be able to make meaningful calculations of the thermodynamic and optical properties of the poly (p-phenylene)'s a new quantum mechanical method was developed - Equilibrium Bond Length (EBL) Theory. Some results of EBL Theory are included.

  16. Dynamics of liquid films and thin jets

    NASA Technical Reports Server (NTRS)

    Zak, M.

    1979-01-01

    The theory of liquid films and thin jets as one- and two-dimensional continuums is examined. The equations of motion have led to solutions for the characteristic speeds of wave propagation for the parameters characterizing the shape. The formal analogy with a compressible fluid indicates the possibility of shock wave generation in films and jets and the formal analogy to the theory of threads and membranes leads to the discovery of some new dynamic effects. The theory is illustrated by examples.

  17. Thin-shell wormholes: Linearization stability

    SciTech Connect

    Poisson, E.; Visser, M.

    1995-12-15

    The class of spherically symmetric thin-shell wormholes provides a particularly elegant collection of exemplars for the study of traversable Lorentzian wormholes. In the present paper we consider linearized (spherically symmetric) perturbations around some assumed static solution of the Einstein field equations. This permits us to relate stability issues to the (linearized) equation of state of the exotic matter which is located at the wormhole throat. {copyright} 1995 The American Physical Society.

  18. Large-area thin-film modules

    NASA Technical Reports Server (NTRS)

    Tyan, Y. S.; Perez-Albuerne, E. A.

    1985-01-01

    The low cost potential of thin film solar cells can only be fully realized if large area modules can be made economically with good production yields. This paper deals with two of the critical challenges. A scheme is presented which allows the simple, economical realization of the long recognized, preferred module structure of monolithic integration. Another scheme reduces the impact of shorting defects and, as a result, increases the production yields. Analytical results demonstrating the utilization and advantages of such schemes are discussed.

  19. Thin sheet casting with electromagnetic pressurization

    DOEpatents

    Walk, Steven R.; Slepian, R. Michael; Nathenson, Richard D.; Williams, Robert S.

    1991-01-01

    An apparatus, method and system for the casting of thin strips or strips of metal upon a moving chill block that includes an electromagnet located so that molten metal poured from a reservoir onto the chill block passes into the magnetic field produced by the electromagnet. The electromagnet produces a force on the molten metal on said chill block in the direction toward said chill block in order to enhance thermal contact between the molten metal and the chill block.

  20. Flexible Thin Metal Film Thermal Sensing System

    NASA Technical Reports Server (NTRS)

    Thomsen, Donald Laurence (Inventor)

    2012-01-01

    A flexible thin metal film thermal sensing system is provided. A thermally-conductive film made from a thermally-insulating material is doped with thermally-conductive material. At least one layer of electrically-conductive metal is deposited directly onto a surface of the thermally-conductive film. One or more devices are coupled to the layer(s) to measure an electrical characteristic associated therewith as an indication of temperature.

  1. High speed thin plate fatigue crack monitor

    NASA Technical Reports Server (NTRS)

    Wincheski, Buzz A. (Inventor); Heyman, Joseph S. (Inventor); Namkung, Min (Inventor); Fulton, James P. (Inventor)

    1996-01-01

    A device and method are provided which non-destructively detect crack length and crack geometry in thin metallic plates. A non-contacting vibration apparatus produces resonant vibrations without introducing extraneous noise. Resulting resonant vibration shifts in cracked plates are correlated to known crack length in plates with similar resonant vibration shifts. In addition, acoustic emissions of cracks at resonance frequencies are correlated to acoustic emissions from known crack geometries.

  2. Microstructure Related Properties of Optical Thin Films.

    NASA Astrophysics Data System (ADS)

    Wharton, John James, Jr.

    Both the optical and physical properties of thin film optical interference coatings depend upon the microstructure of the deposited films. This microstructure is strongly columnar with voids between the columns. Computer simulations of the film growth process indicate that the two most important factors responsible for this columnar growth are a limited mobility of the condensing molecules and self-shadowing by molecules already deposited. During the vacuum deposition of thin films, the microstructure can be influenced by many parameters, such as substrate temperature and vacuum pressure. By controlling these parameters and introducing additional ones, thin film coatings can be improved. In this research, ultraviolet irradiation and ion bombardment were examined as additional parameters. Past studies have shown that post-deposition ultraviolet irradiation can be used to relieve stress and reduce absorption in the far ultraviolet of silicon dioxide films. Ion bombardment has been used to reduce stress, improve packing density, and increase resistance to moisture penetration. Three refractory oxide materials commonly used in thin film coatings were studied; they are silicon dioxide, titanium dioxide, and zirconium dioxide. Both single-layer films and narrowband filters made of these materials were examined. A 1000-watt mercury-xenon lamp was used to provide ultraviolet irradiation. An inverted magnetron ion source was used to produce argon and oxygen ions. Ultraviolet irradiation was found to reduce the absorption and slightly increase the index of refraction in zirconium oxide films. X-ray diffraction analysis revealed that ultraviolet irradiation caused titanium oxide films to become more amorphous; their absorption in the ultraviolet was slightly reduced. No changes were noted in film durability. Ion bombardment enhanced the tetragonal (lll) peak of zirconium oxide but increased the absorption of both zirconium oxide and titanium oxide films. The titanium oxide

  3. Cellulose triacetate, thin film dielectric capacitor

    NASA Technical Reports Server (NTRS)

    Yen, Shiao-Ping S. (Inventor); Jow, T. Richard (Inventor)

    1995-01-01

    Very thin films of cellulose triacetate are cast from a solution containing a small amount of high boiling temperature, non-solvent which evaporates last and lifts the film from the casting surface. Stretched, oriented, crystallized films have high electrical breakdown properties. Metallized films less than about 2 microns in thickness form self-healing electrodes for high energy density, pulsed power capacitors. Thicker films can be utilized as a dielectric for a capacitor.

  4. Cellulose triacetate, thin film dielectric capacitor

    NASA Technical Reports Server (NTRS)

    Yen, Shiao-Ping S. (Inventor); Jow, T. Richard (Inventor)

    1993-01-01

    Very thin films of cellulose triacetate are cast from a solution containing a small amount of high boiling temperature, non-solvent which evaporates last and lifts the film from the casting surface. Stretched, oriented, crystallized films have high electrical breakdown properties. Metallized films less than about 2 microns in thickness form self-healing electrodes for high energy density, pulsed power capacitors. Thicker films can be utilized as a dielectric for a capacitor.

  5. Recording of relativistic particles in thin scintillators

    SciTech Connect

    Tolstukhin, I A.; Somov, Alexander S.; Somov, S. V.; Bolozdynya, A. I.

    2014-11-01

    Results of investigating an assembly of thin scintillators and silicon photomultipliers for registering relativistic particles with the minimum ionization are presented. A high efficiency of registering relativistic particles using an Ej-212 plastic scintillator, BSF-91A wavelength-shifting fiber (Saint-Gobain), and a silicon photomultiplier (Hamamtsu) is shown. The measurement results are used for creating a scintillation hodoscope of the magnetic spectrometer for registering γ quanta in the GlueX experiment.

  6. Dynamics of polymer thin films and surfaces

    NASA Astrophysics Data System (ADS)

    Fakhraai, Zahra

    2007-12-01

    The dynamics of thin polymer films display many differences from the bulk dynamics. Different modes of motions in polymers are affected by confinement in different ways. The enhancement in the dynamics of some modes of motion can cause anomalies in the glass transition temperature (Tg) of thin films, while other modes of motion such as diffusion can be substantially slowed down due to the confinement effects. In this thesis, different modes of dynamics are probed using different techniques. The interface healing of two identical polymer surfaces is used as a probe of segmental motion in the direction normal to the plane of the films and it is shown that this mode of motion is slowed down at temperatures above bulk glass transition, while the glass transition itself is decreased indicating that the type of motion responsible for the glass transition is enhanced. The glass transition measurements at different cooling rates indicate that this enhancement only happens at temperatures close to or below bulk glass transition temperature and it is not expected to be detected at higher temperatures where the system is in the melt state. It is shown that the sample preparation technique is not a factor in observing this enhanced dynamics, while the existence of the free surface can be important in observed reductions in the glass transition temperature. The dynamics near the free surface is further studied using a novel nano-deformation technique, and it is shown that the dynamics near the free surface is in fact enhanced compared to the bulk dynamics and this enhancement is increased as the temperature is decreased further below Tg. It is also shown that this mode of relaxation is much different from the bulk modes of relaxations, and a direct relationship between this enhanced motion and Tg reduction in thin films can be established. The results presented in this thesis can lead to a possible universal picture that can resolve the behavior of different modes of motions in

  7. Superconducting thin films on potassium tantalate substrates

    DOEpatents

    Feenstra, Roeland; Boatner, Lynn A.

    1992-01-01

    A superconductive system for the lossless transmission of electrical current comprising a thin film of superconducting material Y.sub.1 Ba.sub.2 Cu.sub.3 O.sub.7-x epitaxially deposited upon a KTaO.sub.3 substrate. The KTaO.sub.3 is an improved substrate over those of the prior art since the it exhibits small lattice constant mismatch and does not chemically react with the superconducting film.

  8. Packaging material for thin film lithium batteries

    DOEpatents

    Bates, John B.; Dudney, Nancy J.; Weatherspoon, Kim A.

    1996-01-01

    A thin film battery including components which are capable of reacting upon exposure to air and water vapor incorporates a packaging system which provides a barrier against the penetration of air and water vapor. The packaging system includes a protective sheath overlying and coating the battery components and can be comprised of an overlayer including metal, ceramic, a ceramic-metal combination, a parylene-metal combination, a parylene-ceramic combination or a parylene-metal-ceramic combination.

  9. A conserved quantity in thin body dynamics

    NASA Astrophysics Data System (ADS)

    Hanna, J. A.; Pendar, H.

    2016-02-01

    Thin, solid bodies with metric symmetries admit a restricted form of reparameterization invariance. Their dynamical equilibria include motions with both rigid and flowing aspects. On such configurations, a quantity is conserved along the intrinsic coordinate corresponding to the symmetry. As an example of its utility, this conserved quantity is combined with linear and angular momentum currents to construct solutions for the equilibria of a rotating, flowing string, for which it is akin to Bernoulli's constant.

  10. Thin Shell Manufacturing for large Wavefront correctors

    NASA Astrophysics Data System (ADS)

    Ruch, Eric; Poutriquet, Florence

    2011-09-01

    One of the major key elements in large adaptive optical systems is the thin shell, used as a deformable mirror. Although the optical prescriptions are relaxed with respect to a passive mirror, especially in the low spatial frequency domain, other requirements, such as the cosmetic defects (scratch & dig), the tight control of the thickness uniformity and of course the fragility of the piece having an aspect ratio up to 1000:1, generate new problems during the manufacturing, testing and handling of such optics. Moreover, the optical surface has to be tested in two different ways: a classical optical test bench allows us to create a surface map of the mirror. This map is then computed to determine the force required by the actuators to flatten the mirror and this becomes also a specification for polishing and implies a good interaction with the voice coil manufacturer. More than twenty years ago Sagem - Reosc developed the first meter class thin shell for early adaptive optics experiments. Since then, large thin shell have been used as the optical part in composite mirrors and more recently the aspheric shell for the VLT Deformable Secondary Mirror has been polished and prototypes, up to scale 1, of the E-ELT M4 Adaptive Mirror have been delivered to ESO in 2010. This paper will present some recent results in the manufacturing and testing technologies of large this shell, especially focusing on the development of the 1,1 meter convex aspherical shell for the VLT M2 mirror and on the results obtained on the largest thin shell produced so far (2,5 meter in diameter) developed as a demonstrator for the future E-ELT M4.

  11. Structures for dense, crack free thin films

    DOEpatents

    Jacobson, Craig P.; Visco, Steven J.; De Jonghe, Lutgard C.

    2011-03-08

    The process described herein provides a simple and cost effective method for making crack free, high density thin ceramic film. The steps involve depositing a layer of a ceramic material on a porous or dense substrate. The deposited layer is compacted and then the resultant laminate is sintered to achieve a higher density than would have been possible without the pre-firing compaction step.

  12. Making Thin Laminae Of Frozen Alloy Slurries

    NASA Technical Reports Server (NTRS)

    Ghosh, A. K.; Holmes, L. M.; Houston, R. B.; Ecer, G. M.

    1992-01-01

    In new technique, primary objective to develop method to distribute uniformly-thin powder-metal-alloy layers between alternate fiber layers prior to consolidation. Involves use of sheets of frozen alloy powder. These laminae, interspersed with fiber mats, used to make metal/fiber composites. In addition to aerospace applications, this technique, appropriately modified, has potential in the manufacture of future automobile engines or components including molded ceramics.

  13. Microcrystalline organic thin-film solar cells.

    PubMed

    Verreet, Bregt; Heremans, Paul; Stesmans, Andre; Rand, Barry P

    2013-10-11

    Microcrystalline organic films with tunable thickness are produced directly on an indium-tin-oxide substrate, by crystallizing a thin amorphous rubrene film followed by its use as a template for subsequent homoepitaxial growth. These films, with exciton diffusion lengths exceeding 200 nm, produce solar cells with increasing photocurrents at thicknesses up to 400 nm with a fill factor >65%, demonstrating significant potential for microcrystalline organic electronic devices. PMID:23939936

  14. Thin Film Sensors for Surface Measurements

    NASA Technical Reports Server (NTRS)

    Martin, Lisa C.; Wrbanek, John D.; Fralick, Gustave C.

    2001-01-01

    Advanced thin film sensors that can provide accurate surface temperature, strain, and heat flux measurements have been developed at NASA Glenn Research Center. These sensors provide minimally intrusive characterization of advanced propulsion materials and components in hostile, high-temperature environments as well as validation of propulsion system design codes. The sensors are designed for applications on different material systems and engine components for testing in engine simulation facilities. Thin film thermocouples and strain gauges for the measurement of surface temperature and strain have been demonstrated on metals, ceramics and advanced ceramic-based composites of various component configurations. Test environments have included both air-breathing and space propulsion-based engine and burner rig environments at surface temperatures up to 1100 C and under high gas flow and pressure conditions. The technologies developed for these sensors as well as for a thin film heat flux gauge have been integrated into a single multifunctional gauge for the simultaneous real-time measurement of surface temperature, strain, and heat flux. This is the first step toward the development of smart sensors with integrated signal conditioning and high temperature electronics that would have the capability to provide feedback to the operating system in real-time. A description of the fabrication process for the thin film sensors and multifunctional gauge will be provided. In addition, the material systems on which the sensors have been demonstrated, the test facilities and the results of the tests to-date will be described. Finally, the results will be provided of the current effort to demonstrate the capabilities of the multifunctional gauge.

  15. Stable localized patterns in thin liquid films

    NASA Technical Reports Server (NTRS)

    Deissler, Robert J.; Oron, Alexander

    1991-01-01

    We study a 2-D nonlinear evolution equation which describes the 3-D spatiotemporal behavior of the air-liquid interface of a thin liquid film lying on the underside of a cooled horizontal plate. We show that the Marangoni effect can stabilize the destabilizing effect of gravity (the Rayleigh-Taylor instability) allowing for the existence of stable localized axisymmetric solutions for a wide range of parameter values. Various properties of these structures are discussed.

  16. Pulsed laser deposition of pepsin thin films

    NASA Astrophysics Data System (ADS)

    Kecskeméti, G.; Kresz, N.; Smausz, T.; Hopp, B.; Nógrádi, A.

    2005-07-01

    Pulsed laser deposition (PLD) of organic and biological thin films has been extensively studied due to its importance in medical applications among others. Our investigations and results on PLD of a digestion catalyzing enzyme, pepsin, are presented. Targets pressed from pepsin powder were ablated with pulses of an ArF excimer laser ( λ = 193 nm, FWHM = 30 ns), the applied fluence was varied between 0.24 and 5.1 J/cm 2. The pressure in the PLD chamber was 2.7 × 10 -3 Pa. The thin layers were deposited onto glass and KBr substrates. Our IR spectroscopic measurements proved that the chemical composition of deposited thin films is similar to that of the target material deposited at 0.5 and 1.3 J/cm 2. The protein digesting capacity of the transferred pepsin was tested by adapting a modified "protein cube" method. Dissolution of the ovalbumin sections proved that the deposited layers consisted of catalytically active pepsin.

  17. Crystallization of zirconia based thin films.

    PubMed

    Stender, D; Frison, R; Conder, K; Rupp, J L M; Scherrer, B; Martynczuk, J M; Gauckler, L J; Schneider, C W; Lippert, T; Wokaun, A

    2015-07-28

    The crystallization kinetics of amorphous 3 and 8 mol% yttria stabilized zirconia (3YSZ and 8YSZ) thin films grown by pulsed laser deposition (PLD), spray pyrolysis and dc-magnetron sputtering are explored. The deposited films were heat treated up to 1000 °C ex situ and in situ in an X-ray diffractometer. A minimum temperature of 275 °C was determined at which as-deposited amorphous PLD grown 3YSZ films fully crystallize within five hours. Above 325 °C these films transform nearly instantaneously with a high degree of micro-strain when crystallized below 500 °C. In these films the t'' phase crystallizes which transforms at T > 600 °C to the t' phase upon relaxation of the micro-strain. Furthermore, the crystallization of 8YSZ thin films grown by PLD, spray pyrolysis and dc-sputtering are characterized by in situ XRD measurements. At a constant heating rate of 2.4 K min(-1) crystallization is accomplished after reaching 800 °C, while PLD grown thin films were completely crystallized already at ca. 300 °C. PMID:26119755

  18. Thin film phase transition materials development program

    NASA Astrophysics Data System (ADS)

    Case, W. E.

    1985-04-01

    A number of application concepts have emerged based on the idea that a phase transition thin film such as vanadium dioxide provides a high resolution, two-dimensional format for switching, recording, and processing optical signals. These applications range from high density optical disk recording systems and optical data processing to laser protection devices, infrared FLIRS and seekers, laser radar systems and IR scene simulators. All application candidates have a potential for providing either a totally new capability, an improved performance, a lower cost, or combinations of the three. Probably of greatest significance is the emergence of agile sensor concepts arising out of some of the film's special properties. These are represented by the above FLIRs, seekers and laser radar systems. A three year research program has been completed to advance the state-of-the-art in the preparation and characterization of selected thin film phase transition materials. The objectives of the program were: (1) to expand the data base and improve operational characteristics of Vought prepared vanadium dioxide thin films, (2) to evolve process chemistry and subsequently characterize several new program materials, including rare-earth chalcogenides, organic semiconductor charge complexes, alloys of transition metal oxides, and metal-insulator cermets, and (3) to spin-off new applications and concepts.

  19. Molecular theory of liquid crystal thin films

    NASA Astrophysics Data System (ADS)

    Meng, Shihong

    A molecular theory has been developed to describe the isotropic-nematic transitoon of model nematogens in bulk and in thin films. The surfaces of thin films can be hard surfaces or coated with surfactant monolayers. The theory only includes hard body interactions between all molecule species: solvent, nematogens and surfactants. We have studied the influence of the separation between confining walls, concentration of nematogens, as well as the surface anchoring and areal density of surfactant at the interface upon the phases of nematogens. We have explained the possible existence of planar degenerate phase through entropic pictures and have confirmed close to the bulk isotropic-nematic transition point, the order of the phases of nematogens from isotropic to nematic then back to isotropic when varying the areal density of surfactant monolayers at interfaces. From the results obtained, we believe that we have captured the main competing interactions between surfactants and nematogens and our molecular level theory is capable of describing these two interactions of different natures. Our results can provide a guideline for molecular design of biosensors. We have modeled the molecular systems with as much simplification as possible while retaining the main features. The thesis is arranged into introduction, results on bulk, thin films confined between hard walls and between surfactant monolayers.

  20. Deuterium storage in nanocrystalline magnesium thin films

    NASA Astrophysics Data System (ADS)

    Checchetto, R.; Bazzanella, N.; Miotello, A.; Brusa, R. S.; Zecca, A.; Mengucci, A.

    2004-02-01

    Nanocrystalline magnesium deuteride thin films with the β-MgD2 structure were prepared by vacuum evaporation of hexagonal magnesium (h-Mg) samples and thermal annealing in 0.15 MPa D2 atmosphere at 373 K. Thermal desorption spectroscopy analysis indicated that the rate-limiting step in the deuterium desorption was given by the thermal decomposition of the deuteride phase. The activation energy Δg of the β-MgD2→h-Mg+D2 reaction scaled from 1.13±0.03 eV in 650-nm-thick films to 1.01±0.02 eV in 75-nm-thick films most likely as consequence of different stress and defect level. Positron annihilation spectroscopy analysis of the thin-film samples submitted to deuterium absorption and desorption cycles reveal the presence of a high concentration of void-like defects in the h-Mg layers after the very first decomposition of the β-MgD2 phase, the presence of these open volume defects reduces the D2 absorption capacity of the h-Mg thin film.

  1. Polycrystalline thin film materials and devices

    SciTech Connect

    Baron, B.N.; Birkmire, R.W.; Phillips, J.E.; Shafarman, W.N.; Hegedus, S.S.; McCandless, B.E. . Inst. of Energy Conversion)

    1992-10-01

    Results of Phase II of a research program on polycrystalline thin film heterojunction solar cells are presented. Relations between processing, materials properties and device performance were studied. The analysis of these solar cells explains how minority carrier recombination at the interface and at grain boundaries can be reduced by doping of windows and absorber layers, such as in high efficiency CdTe and CuInSe{sub 2} based solar cells. The additional geometric dimension introduced by the polycrystallinity must be taken into consideration. The solar cells are limited by the diode current, caused by recombination in the space charge region. J-V characteristics of CuInSe{sub 2}/(CdZn)S cells were analyzed. Current-voltage and spectral response measurements were also made on high efficiency CdTe/CdS thin film solar cells prepared by vacuum evaporation. Cu-In bilayers were reacted with Se and H{sub 2}Se gas to form CuInSe{sub 2} films; the reaction pathways and the precursor were studied. Several approaches to fabrication of these thin film solar cells in a superstrate configuration were explored. A self-consistent picture of the effects of processing on the evolution of CdTe cells was developed.

  2. Thin-film cadmium telluride solar cells

    NASA Astrophysics Data System (ADS)

    Chu, T. L.

    1987-10-01

    Cadmium telluride, with a room-temperature band-gap energy of 1.5 eV, is a promising thin-film photovoltaic material. The major objective of this research has been to demonstrate thin-film CdTe heterojunction solar cells with a total area greater than 1 sq cm and photovoltaic efficiencies of 13 percent or more. Thin-film p-CdTe/CdS/SnO2:F/glass solar cells with an AM1.5 efficiency of 10.5 percent have been reported previously. This report contains results of work done on: (1) the deposition, resistivity control, and characterization of p-CdTe films by the close-spaced sublimation process; (2) the deposition of large-band-gap window materials; (3) the electrical properties of CdS/CdTe heterojunctions; (4) the formation of stable, reproducible, ohmic contacts (such as p-HgTe) to p-CdTe; and (5) the preparation and evaluation of heterojunction solar cells.

  3. Thin-film cadmium telluride solar cells

    NASA Astrophysics Data System (ADS)

    1986-09-01

    This is the final technical progress report of a research program entitled Thin-Film Cadmium Telluride Solar Cells. The major objective was to demonstrate chemical vapor deposition (CVD)-grown CdTe devices with a photovoltaic efficiency of at least 10%. The work included: (1) CVD and characterization of p-CdTe films of controlled resistivity; (2) deposition and characterization of heterojunction partners; (3) surface passivation of CdTe; and (4) preparation and characterization of thin-film solar cells. The CVD of p-CdTe was optimized with emphasis on resistivity control through nonstoichiometry and extrinsic doping. Both carbon and oxygen were identified as acceptors. The use of thermal oxidation for surface passivation of CdTe was investigated using capacitance-voltage measurement. Device-quality thermal oxide can be prepared by hydrogen annealing of CdTe before oxidation. Deposition and characterization of CdS, CdO, and ZnO:In were also carried out. The best thin-film cell to date had a conversion efficiency near 9%.

  4. Surface photovoltage spectroscopy of thin films

    NASA Astrophysics Data System (ADS)

    Leibovitch, M.; Kronik, L.; Fefer, E.; Burstein, L.; Korobov, V.; Shapira, Yoram

    1996-06-01

    The surface photovoltage (SPV) spectrum due to subband-gap illumination of thin films is theoretically studied. It is shown that this SPV is inherently sensitive to buried interfaces just as it is sensitive to the external semiconductor surface. The different contributions to the SPV from all the optically active gap states present within a sample, consisting of a bulk substrate covered by a thin film, are analyzed. Analytical expressions are obtained in the low illumination intensity and the depletion approximation regime. The evolution of the SPV spectrum with film thickness is examined and is found to depend on both site and population of the gap states. Three modes of evolution are found, according to the relative importance of gap state population changes with film thickness. These modes are confirmed by a numerical simulation of a thin film of pseudomorphic InAlAs on InP substrates and by experiments conducted on the same system. The approach is also applied to the InP/In2O3 system, revealing gap state formation, followed by filling with electrons, thereby explaining previous observations of nearly ideal I-V behavior at this junction.

  5. A new look on blood shear thinning

    NASA Astrophysics Data System (ADS)

    Abkarian, Manouk; Lanotte, Luca; Fromental, Jean-Marc; Mendez, Simon; Fedosov, Dmitry; Gompper, Gerhard; Mauer, Johannes; Claveria, Viviana

    2015-11-01

    Blood is a shear-thinning fluid. At shear rates γ˙ < 1 s-1 , its drop of viscosity has been related primarily to the breaking-up of networks of ``rouleaux'' formed by stacked red blood cells (RBCs). For higher γ˙ in the range 10 - 1000 s-1 , where RBCs flow as single elements, studies demonstrated that RBCs suspended in a viscous fluid mimicking the viscosity of whole blood, deformed into ellipsoids aligned steadily in the direction of the flow, while their membrane rotated about their center of mass like a tank-tread. Such drop-like behavior seemed to explain shear-thinning. Here, using rheometers, microfluidics and simulations, we show that the dynamics of single RBCs in plasma-like fluids display a different sequence of deformation for increasing shear rates going from discocytes to successively, stomatocytes, folded stomatocytes, trilobes and tetralobes, but never ellipsoids. This result is also identical for physiological hematocrits. We correlate this shape diagram to the different regimes in blood rheology for high shear rates and propose a new-look on the interpretation of blood shear-thinning behavior.

  6. Thinning and thickening in active microrheology

    NASA Astrophysics Data System (ADS)

    Wang, Ting; Sperl, Matthias

    2016-02-01

    When pulling a probe particle in a many-particle system at a fixed velocity, the probe's effective friction, defined as the average external force over its velocity, γeff:= /u , first stays constant (linear response), then decreases (thinning), and, finally, increases again (thickening). We propose a three-time-scale picture to describe the thinning and thickening behavior. There are three distinct time scales for the bath particles: diffusion, damping, and single probe-bath collision. The dominating time scales are controlled by the pulling velocity and determine the behavior of the probe's friction. We test and confirm this description with a Langevin dynamics simulation. Microscopically, we find that for computing the effective friction, the Maxwellian distribution of bath particles' velocities fails in the regime of high Reynolds and Peclet numbers. This can be understood based on the microscopic mechanism of thickening obtained in the T =0 limit. The dynamic regimes defined by the ratio of different time scales can explain several observations of thinning and thickening in literature.

  7. Cortical thinning in former professional soccer players.

    PubMed

    Koerte, Inga K; Mayinger, Michael; Muehlmann, Marc; Kaufmann, David; Lin, Alexander P; Steffinger, Denise; Fisch, Barbara; Rauchmann, Boris-Stephan; Immler, Stefanie; Karch, Susanne; Heinen, Florian R; Ertl-Wagner, Birgit; Reiser, Maximilian; Stern, Robert A; Zafonte, Ross; Shenton, Martha E

    2016-09-01

    Soccer is the most popular sport in the world. Soccer players are at high risk for repetitive subconcussive head impact when heading the ball. Whether this leads to long-term alterations of the brain's structure associated with cognitive decline remains unknown. The aim of this study was to evaluate cortical thickness in former professional soccer players using high-resolution structural MR imaging. Fifteen former male professional soccer players (mean age 49.3 [SD 5.1] years) underwent high-resolution structural 3 T MR imaging, as well as cognitive testing. Fifteen male, age-matched former professional non-contact sport athletes (mean age 49.6 [SD 6.4] years) served as controls. Group analyses of cortical thickness were performed using voxel-based statistics. Soccer players demonstrated greater cortical thinning with increasing age compared to controls in the right inferolateral-parietal, temporal, and occipital cortex. Cortical thinning was associated with lower cognitive performance as well as with estimated exposure to repetitive subconcussive head impact. Neurocognitive evaluation revealed decreased memory performance in the soccer players compared to controls. The association of cortical thinning and decreased cognitive performance, as well as exposure to repetitive subconcussive head impact, further supports the hypothesis that repetitive subconcussive head impact may play a role in early cognitive decline in soccer players. Future studies are needed to elucidate the time course of changes in cortical thickness as well as their association with impaired cognitive function and possible underlying neurodegenerative process. PMID:26286826

  8. Current Sheet Thinning Associated with Dayside Reconnection

    NASA Astrophysics Data System (ADS)

    Hsieh, M.; Otto, A.; Ma, X.

    2011-12-01

    The thinning of the near-Earth current sheet during the growth phase is of critical importance to understand geomagnetic substorms and the conditions that lead to the onset of the expansion phase. We have proposed that convection from the midnight tail region to the dayside as the cause for this current sheet thinning. Adiabatic convection from the near-Earth tail region toward the dayside must conserve the entropy on magnetic field lines. This constraint prohibits a source of the magnetic flux from a region further out in the magnetotail. Thus the near-Earth tail region is increasingly depleted of magnetic flux (the Erickson and Wolf [1980] problem) with entropy matching that of flux tubes that are eroded on the dayside. The process is examined by three-dimensional MHD simulations. The properties of the current sheet thinning are determined as a function of the magnitude of convection toward the dayside and the lobe boundary conditions. It is shown that the model yields a time scale, location, and other general characteristics of the current sheet evolution consistent with observations during the substorm growth phase.

  9. Silver nanowire composite thin films as transparent electrodes for Cu(In,Ga)Se₂/ZnS thin film solar cells.

    PubMed

    Tan, Xiao-Hui; Chen, Yu; Liu, Ye-Xiang

    2014-05-20

    Solution processed silver nanowire indium-tin oxide nanoparticle (AgNW-ITONP) composite thin films were successfully applied as the transparent electrodes for Cu(In,Ga)Se₂ (CIGS) thin film solar cells with ZnS buffer layers. Properties of the AgNW-ITONP thin film and its effects on performance of CIGS/ZnS thin film solar cells were studied. Compared with the traditional sputtered ITO electrodes, the AgNW-ITONP thin films show comparable optical transmittance and electrical conductivity. Furthermore, the AgNW-ITONP thin film causes no physical damage to the adjacent surface layer and does not need high temperature annealing, which makes it very suitable to use as transparent conductive layers for heat or sputtering damage-sensitive optoelectronic devices. By using AgNW-ITONP electrodes, the required thickness of the ZnS buffer layers for CIGS thin film solar cells was greatly decreased. PMID:24922214

  10. Imaging Electrons in Ultra-thin Nanowires

    NASA Astrophysics Data System (ADS)

    Boyd, Erin E.

    2011-12-01

    Ultra-thin semiconductor nanowires are promising systems in which to explore novel low-dimensional physics and are attractive candidates for future nanoelectronics. Ultra-thin nanowires with diameters of 20 to 30 nm are essentially one-dimensional (ID) for moderate electron number, because only one radial subband is occupied. Low-temperature scanning gate microscopy is especially well suited for improving our understanding of nanowires in order to optimize the construction of nanowire systems. We use a home-built liquid-He cooled scanning gate microscope (SGM) to probe and manipulate electrons beneath the surface of devices. The SGM's conductance images are obtained by scanning the charged SGM tip above the sample and recording the change in conductance through the device as a function of tip position. We present simulations of extracting the amplitude of the 1D electron wavefunction along the length of the quantum dot in an ultra-thin InAs/InP heterostructure nanowire (diameter = 30 nm) using a SGM. A weakly perturbing SGM tip slightly dents the electron wavefunction inside the quantum dot, and we propose measuring the change in energy of the dot due to the perturbation as a function of tip position. By measuring the change in energy of the dot and by knowing the form of the tip potential, the amplitude of the wavefunction can be found. This extraction technique could serve as a powerful tool to improve our understanding of electron behavior in quasi-1 D systems. We have used our SGM to image the conductance through an ultra-thin (diameter ˜ 30 nm) 1nAs nanowire with two InP barriers. Our imaging technique provides detailed information regarding the position and flow of electrons in the nanowire. We demonstrate that the charged SPM tip's position or voltage can be used to control the number of electrons on the quantum dots. We spatially locate three quantum dots in series along the length of the ultra-thin nanowire. Using energy level spectroscopy and the

  11. LiMn2O4-based cathode thin films for Li thin-film batteries

    NASA Astrophysics Data System (ADS)

    Yim, Haena; Shin, Dong-Wook; Choi, Ji-Won

    2016-01-01

    Substitution methods for Mn3+ in a spinel lithium manganese oxide with other cations have been used to prevent capacity degradation during the electrochemical charge and discharge of Li-batteries by increasing the average valence of Mn. In particular, in this review we outlin the effects of Sn substitution on the cycling performance of LiMn2O4 thin films that can be used as positive electrode in Li-batteries. The thin films were prepared by using pulsed laser deposition and solution deposition with regard to the structural and the electro-chemical characteristics.

  12. Properties of ultra-thin lead zirconate titanate thin films prepared by ozone jet reactive evaporation

    NASA Astrophysics Data System (ADS)

    Torii, Kazuyoshi; Kawakami, Hirosi; Miki, Hiroshi; Kushida, Keiko; Fujisaki, Yoshihisa

    1997-03-01

    Lead zirconate titanate (PZT) thin films were prepared by reactive coevaporation with high-concentration ozone. PZT thin films that demonstrate the highest charge storage density (280 fC/μm2 at 1.5 V for 75-nm-thick film) yet reported have been fabricated. No fatigue was observed after 1011 polarization switching cycles even though a Pt electrode is used. A low leakage current of <10-7 A/cm2 at 1.5 V was attained. These PZT films are promising candidates of an alternative capacitor dielectric for dynamic random access memory (DRAM) and ferroelectric nonvolatile memories.

  13. Polycrystalline-thin-film thermophotovoltaic cells

    NASA Astrophysics Data System (ADS)

    Dhere, Neelkanth G.

    1996-02-01

    Thermophotovoltaic (TPV) cells convert thermal energy to electricity. Modularity, portability, silent operation, absence of moving parts, reduced air pollution, rapid start-up, high power densities, potentially high conversion efficiencies, choice of a wide range of heat sources employing fossil fuels, biomass, and even solar radiation are key advantages of TPV cells in comparison with fuel cells, thermionic and thermoelectric convertors, and heat engines. The potential applications of TPV systems include: remote electricity supplies, transportation, co-generation, electric-grid independent appliances, and space, aerospace, and military power applications. The range of bandgaps for achieving high conversion efficiencies using low temperature (1000-2000 K) black-body or selective radiators is in the 0.5-0.75 eV range. Present high efficiency convertors are based on single crystalline materials such as In1-xGaxAs, GaSb, and Ga1-xInxSb. Several polycrystalline thin films such as Hg1-xCdxTe, Sn1-xCd2xTe2, and Pb1-xCdxTe, etc., have great potential for economic large-scale applications. A small fraction of the high concentration of charge carriers generated at high fluences effectively saturates the large density of defects in polycrystalline thin films. Photovoltaic conversion efficiencies of polycrystalline thin films and PV solar cells are comparable to single crystalline Si solar cells, e.g., 17.1% for CuIn1-xGaxSe2 and 15.8% for CdTe. The best recombination-state density Nt is in the range of 10-15-10-16 cm-3 acceptable for TPV applications. Higher efficiencies may be achieved because of the higher fluences, possibility of bandgap tailoring, and use of selective emitters such as rare earth oxides (erbia, holmia, yttria) and rare earth-yttrium aluminium garnets. As compared to higher bandgap semiconductors such as CdTe, it is easier to dope the lower bandgap semiconductors. TPV cell development can benefit from the more mature PV solar cell and opto

  14. Back diffusion from thin low permeability zones.

    PubMed

    Yang, Minjune; Annable, Michael D; Jawitz, James W

    2015-01-01

    Aquitards can serve as long-term contaminant sources to aquifers when contaminant mass diffuses from the aquitard following aquifer source mass depletion. This study describes analytical and experimental approaches to understand reactive and nonreactive solute transport in a thin aquitard bounded by an adjacent aquifer. A series of well-controlled laboratory experiments were conducted in a two-dimensional flow chamber to quantify solute diffusion from a high-permeability sand into and subsequently out of kaolinite clay layers of vertical thickness 15 mm, 20 mm, and 60 mm. One-dimensional analytical solutions were developed for diffusion in a finite aquitard with mass exchange with an adjacent aquifer using the method of images. The analytical solutions showed very good agreement with measured breakthrough curves and aquitard concentration distributions measured in situ by light reflection visualization. Solutes with low retardation accumulated more stored mass with greater penetration distance in the aquitard compared to high-retardation solutes. However, because the duration of aquitard mass release was much longer, high-retardation solutes have a greater long-term back diffusion risk. The error associated with applying a semi-infinite domain analytical solution to a finite diffusion domain increases as a function of the system relative diffusion length scale, suggesting that the solutions using image sources should be applied in cases with rapid solute diffusion and/or thin clay layers. The solutions presented here can be extended to multilayer aquifer/low-permeability systems to assess the significance of back diffusion from thin layers. PMID:25478850

  15. Metallic Thin-Film Bonding and Alloy Generation

    NASA Technical Reports Server (NTRS)

    Fryer, Jack Merrill (Inventor); Campbell, Geoff (Inventor); Peotter, Brian S. (Inventor); Droppers, Lloyd (Inventor)

    2016-01-01

    Diffusion bonding a stack of aluminum thin films is particularly challenging due to a stable aluminum oxide coating that rapidly forms on the aluminum thin films when they are exposed to atmosphere and the relatively low meting temperature of aluminum. By plating the individual aluminum thin films with a metal that does not rapidly form a stable oxide coating, the individual aluminum thin films may be readily diffusion bonded together using heat and pressure. The resulting diffusion bonded structure can be an alloy of choice through the use of a carefully selected base and plating metals. The aluminum thin films may also be etched with distinct patterns that form a microfluidic fluid flow path through the stack of aluminum thin films when diffusion bonded together.

  16. Low-Cost Detection of Thin Film Stress during Fabrication

    NASA Technical Reports Server (NTRS)

    Nabors, Sammy A.

    2015-01-01

    NASA's Marshall Space Flight Center has developed a simple, cost-effective optical method for thin film stress measurements during growth and/or subsequent annealing processes. Stress arising in thin film fabrication presents production challenges for electronic devices, sensors, and optical coatings; it can lead to substrate distortion and deformation, impacting the performance of thin film products. NASA's technique measures in-situ stress using a simple, noncontact fiber optic probe in the thin film vacuum deposition chamber. This enables real-time monitoring of stress during the fabrication process and allows for efficient control of deposition process parameters. By modifying process parameters in real time during fabrication, thin film stress can be optimized or controlled, improving thin film product performance.

  17. Charge multiplication effect in thin diamond films

    NASA Astrophysics Data System (ADS)

    Skukan, N.; Grilj, V.; Sudić, I.; Pomorski, M.; Kada, W.; Makino, T.; Kambayashi, Y.; Andoh, Y.; Onoda, S.; Sato, S.; Ohshima, T.; Kamiya, T.; Jakšić, M.

    2016-07-01

    Herein, we report on the enhanced sensitivity for the detection of charged particles in single crystal chemical vapour deposition (scCVD) diamond radiation detectors. The experimental results demonstrate charge multiplication in thin planar diamond membrane detectors, upon impact of 18 MeV O ions, under high electric field conditions. Avalanche multiplication is widely exploited in devices such as avalanche photo diodes, but has never before been reproducibly observed in intrinsic CVD diamond. Because enhanced sensitivity for charged particle detection is obtained for short charge drift lengths without dark counts, this effect could be further exploited in the development of sensors based on avalanche multiplication and radiation detectors with extreme radiation hardness.

  18. Liquid phase deposition of electrochromic thin films

    SciTech Connect

    Richardson, Thomas J.; Rubin, Michael D.

    2000-08-18

    Thin films of titanium, zirconium and nickel oxides were deposited on conductive SnO2:F glass substrates by immersion in aqueous solutions. The films are transparent, conformal, of uniform thickness and appearance, and adhere strongly to the substrates. On electrochemical cycling, TiO2, mixed TiO2-ZrO2, and NiOx films exhibited stable electrochromism with high coloration efficiencies. These nickel oxide films were particularly stable compared with films prepared by other non-vacuum techniques. The method is simple, inexpensive, energy efficient, and readily scalable to larger substrates.

  19. Interface Effects in Perovskite Thin Films

    NASA Astrophysics Data System (ADS)

    Lepetit, Marie-Bernadette; Mercey, Bernard; Simon, Charles

    2012-02-01

    The control of matter properties (transport, magnetic, dielectric,…) using synthesis as thin films is strongly hindered by the lack of reliable theories, able to guide the design of new systems, through the understanding of the interface effects and of the way the substrate constraints are imposed on the material. The present Letter analyzes the energetic contributions at the interfaces, and proposes a model describing the microscopic mechanisms governing the interactions at an epitaxial interface between a manganite and another transition metal oxide in perovskite structure (as for instance SrTiO3). The model is checked against experimental results and literature analysis.

  20. Arcetri Spectral Code for Thin Plasmas

    NASA Astrophysics Data System (ADS)

    Landi, E.; Landini, M.

    2010-07-01

    The Arcetri spectral code allows to evaluate the spectrum of the radiation emitted by hot and optically thin plasmas in the spectral range 1 - 2000 Angstroms. The database has been updated including atomic data and radiative and collisional rates to calculate level population and line emissivities for a number of ions of the minor elements; a critical compilation of the electron collision excitation for these elements has been performed. The present version of the program includes the CHIANTI database for the most abundant elements, the minor elements data, and Fe III atomic model, radiative and collisional data.

  1. The Arcetri spectral code for thin plasmas

    NASA Astrophysics Data System (ADS)

    Landi, E.; Landini, M.

    1998-12-01

    The Arcetri spectral code allows to evaluate the spectrum of the radiation emitted by hot and optically thin plasmas in the spectral range 1 - 2000 Angstroms. The database has been updated including atomic data and radiative and collisional rates to calculate level population and line emissivities for a number of ions of the minor elements; a critical compilation of the electron collision excitation for these elements has been performed. The present version of the program includes the CHIANTI database for the most abundant elements, the minor elements data, and Fe III atomic model, radiative and collisional data.

  2. Nanostructured thin films and their macrobehaviors

    NASA Astrophysics Data System (ADS)

    Lo, Mei-Ling; Liao, Shih-Fang; Lee, Cheng-Chung

    2014-08-01

    The iridescence green band and cyan tail of the wing on Papilio blumei butterfly were investigated. The bi-color phenomenon on the scales of butterfly wings was found and analyzed. The spectral change with thickness of chitin-air layers, width of air hole, total layer numbers and incident angle of light were simulated by FDTD method. 2D photonic-crystal model was applied to explain the change of reflectance spectra and color with angle. The replica of structural color and nanostructured thin films for Papilio blumei butterflies was fabricated successfully by three main techniques, PS spheres bedding, electron-beam gun evaporation and ICP etching.

  3. Ultrahigh stability of atomically thin metallic glasses

    SciTech Connect

    Cao, C. R.; Huang, K. Q.; Zhao, N. J.; Sun, Y. T.; Bai, H. Y.; Gu, L. E-mail: dzheng@iphy.ac.cn Zheng, D. N. E-mail: dzheng@iphy.ac.cn Wang, W. H. E-mail: dzheng@iphy.ac.cn

    2014-07-07

    We report the fabrication and study of thermal stability of atomically thin ZrCu-based metallic glass films. The ultrathin films exhibit striking dynamic properties, ultrahigh thermal stability, and unique crystallization behavior with discrete crystalline nanoparticles sizes. The mechanisms for the remarkable high stability and crystallization behaviors are attributed to the dewetting process of the ultrathin film. We demonstrated a promising avenue for understanding some fundamental issues such as glassy structure, crystallization, deformation, and glass formation through atomic resolution imaging of the two dimensional like metallic glasses.

  4. Study of Laser Interaction with Thin Targets

    SciTech Connect

    Boley, C D; Cutter, K P; Fochs, S N; Pax, P H; Rotter, M D; Rubenchik, A M; Yamamoto, R M

    2009-03-06

    For many targets of interest, the thickness is small compared to the conduction length during the engagement. In addition, the laser-material interaction region can be treated as flat. We have studied this regime with our 25 kW solid-state laser. We have demonstrated that airflow can reduce by approximately 40% the energy required to break through a thin target. This reduction is caused by the bulging of the softened material and the tearing and removal of the material by aerodynamic forces. We present elastic modeling which explains these results.

  5. Robust, Thin Optical Films for Extreme Environments

    NASA Technical Reports Server (NTRS)

    2006-01-01

    The environment of space presents scientists and engineers with the challenges of a harsh, unforgiving laboratory in which to conduct their scientific research. Solar astronomy and X-ray astronomy are two of the more challenging areas into which NASA scientists delve, as the optics for this high-tech work must be extremely sensitive and accurate, yet also be able to withstand the battering dished out by radiation, extreme temperature swings, and flying debris. Recent NASA work on this rugged equipment has led to the development of a strong, thin film for both space and laboratory use.

  6. Investigating the interfacial dynamics of thin films

    NASA Astrophysics Data System (ADS)

    Rosenbaum, Aaron W.

    This thesis probes the interfacial dynamics and associated phenomena of thin films. Surface specific tools were used to study the self-assembly of alkanethiols, the mono- and bilayer dynamics of SF6, and the surface motion of poly(methyl methacrylate). Non-pertubative helium atom scattering was the principal technique used to investigate these systems. A variety of other complementary tools, including scanning tunneling microscopy, electron diffraction, Auger spectroscopy, atomic force microscopy, and ellipsometry were used in tandem with the neutral atom scattering studies. Controlling the spontaneous assembly of alkanethiols on Au(111) requires a better fundamental understanding of the adsorbate-adsorbate and substrate-adsorbate interactions. Our characterization focused on two key components, the surface structure and adsorbate vibrations. The study indicates that the Au(111) reconstruction plays a larger role than anticipated in the low-density phase of alkanethiol monolayers. A new structure is proposed for the 1-decanethiol monolayer that impacts the low-energy vibrational mode. Varying the alkane chain lengths imparts insight into the assembly process via characterization of a dispersionless phonon mode. Studies of SF6 physisorbed on Au(111) bridge surface research on rare gas adsorbates with complicated dynamical organic thin films. Mono- and bilayer coverages of SF6/Au(111) were studied at cryogenic temperatures. Our experiments probed the surface properties of SF6 yielding insights into substrate and coverage effects. The study discovered a dispersionless Einstein oscillation with multiple harmonic overtones. A second layer of SF6 softened the mode, but did not show any indications of bulk or cooperative interactions. The vibrational properties of SF 6 showed both striking similarities and differences when compared with physisorbed rare gases. Lastly, this thesis will discuss studies of thin film poly(methyl methacrylate) on Si. The non-pertubative and

  7. Flat or curved thin optical display panel

    DOEpatents

    Veligdan, J.T.

    1995-01-10

    An optical panel includes a plurality of waveguides stacked together, with each waveguide having a first end and an opposite second end. The first ends collectively define a first face, and the second ends collectively define a second face of the panel. The second face is disposed at an acute face angle relative to the waveguides to provide a panel which is relatively thin compared to the height of the second face. In an exemplary embodiment for use in a projection TV, the first face is substantially smaller in height than the second face and receives a TV image, with the second face defining a screen for viewing the image enlarged. 7 figures.

  8. Transient scattering from a thin arbitrary wire

    NASA Astrophysics Data System (ADS)

    Mohan, S. Ananda; Rao, Sadasiva M.

    1988-08-01

    The conjugate gradient (CG) method is applied to solve the problem of transient scattering from a thin arbitrary wire. The method is simple, efficient, and yields more accurate results than the marching-on-in-time procedure. Numerical examples for the case of a bent wire, a wire with discontinuous radii, and a circular loop are presented to highlight the advantages of this procedure. It is concluded that the occurrence of late-time oscillations may not be due to the accumulation of truncation of roundoff errors. These oscillations may be attributed to the insufficient sampling of the structure.

  9. Strong terahertz absorption using thin metamaterial structures

    SciTech Connect

    Alves, Fabio; Kearney, Brian; Grbovic, Dragoslav; Lavrik, Nickolay V; Karunasiri, Gamani

    2012-01-01

    Metamaterial absorbers with nearly 100% absorption in the terahertz (THz) spectral band have been designed and fabricated using a periodic array of aluminum (Al) squares and an Al ground plane separated by a thin silicon dioxide (SiO{sub 2}) dielectric film. The entire structure is less than 1.6 mm thick making it suitable for the fabrication of microbolometers or bi-material sensors for THz imaging. Films with different dielectric layer thicknesses exhibited resonant absorption at 4.1, 4.2, and 4.5 THz with strengths of 98%, 95%, and 88%, respectively. The measured absorption spectra are in good agreement with simulations using finite element modeling.

  10. Gas adsorption on microporous carbon thin films

    SciTech Connect

    O'Shea, S.; Pailthorpe, B.A.; Collins, R.E.; Furlong, D.N. )

    1992-05-01

    A gas adsorption study was performed on amorphous hydrogenated carbon thin films which are deposited by reactive magnetron sputtering using acetylene gas. It is found that the films are highly microporous. Annealing significantly increases the adsorption capacity of the films and decreases the effects of low-pressure hysteresis in the adsorption isotherms. The general gas adsorption behavior closely resembles that of powdered activated carbons. The Dubinin-Radushkevich equation can be used to model the submonolayer adsorption isotherm for a variety of gases. 38 refs., 9 figs., 3 tabs.

  11. Laser Cutting of Thin Nickel Bellows

    NASA Technical Reports Server (NTRS)

    Butler, C. L.

    1986-01-01

    Laser cutting technique produces narrow, precise, fast, and repeatable cuts in thin nickel-allow bellows material. Laser cutting operation uses intense focused beam to melt material and assisting gas to force melted material through part thickness, creating void. When part rotated or moved longitudinally, melting and material removal continuous and creates narrow, fast, precise, and repeatable cut. Technique used to produce cuts of specified depths less than material thickness. Avoids distortion, dents, and nicks produced in delicate materials during lathe trimming operations, which require high cutting-tool pressure and holding-fixture forces.

  12. FDTD modeling of thin impedance sheets

    NASA Technical Reports Server (NTRS)

    Luebbers, Raymond; Kunz, Karl

    1991-01-01

    Thin sheets of resistive or dielectric material are commonly encountered in radar cross section calculations. Analysis of such sheets is simplified by using sheet impedances. It is shown that sheet impedances can be modeled easily and accurately using Finite Difference Time Domain (FDTD) methods. These sheets are characterized by a discontinuity in the tangential magnetic field on either side of the sheet but no discontinuity in tangential electric field. This continuity, or single valued behavior of the electric field, allows the sheet current to be expressed in terms of an impedance multiplying this electric field.

  13. Geometry of Thin Nematic Elastomer Sheets

    NASA Astrophysics Data System (ADS)

    Aharoni, Hillel; Sharon, Eran; Kupferman, Raz

    A thin sheet of nematic elastomer attains 3D configurations depending on the nematic director field upon heating. In this talk we describe the intrinsic geometry of such a sheet, and derive an expression for the metric induced by general smooth nematic director fields. Furthermore, we investigate the reverse problem of constructing a director field that induces a specified 2D geometry. We provide an explicit analytical recipe for constructing any surface of revolution using this method. We demonstrate how the design of an arbitrary 2D geometry is accessible using approximate numerical methods.

  14. More About Thin-Membrane Biosensor

    NASA Technical Reports Server (NTRS)

    Case, George D.; Worley, Jennings F., III

    1994-01-01

    Report presents additional information about device described in "Thin-Membrane Sensor With Biochemical Switch" (MFS-26121). Device is modular sensor that puts out electrical signal indicative of chemical or biological agent. Signal produced as membrane-crossing ion current triggered by chemical reaction between agent and recognition protein conjugated to channel blocker. Prototype of biosensor useful in numerous laboratory, industrial, or field applications; such as to detect bacterial toxins in food, to screen for disease-producing micro-organisms, or to warn of toxins or pollutants in air.

  15. Nonlinear viscoelastic characterization of thin polyethylene film

    NASA Technical Reports Server (NTRS)

    Wilbeck, J. S.

    1981-01-01

    In order to understand the state of stress and strain in a typical balloon fabricated from thin polyethylene film, experiment data in the literature reviewed. It was determined that the film behaves as a nonlinear viscoelasticity material and should be characterized accordingly. A simple uniaxial, nonlinear viscoelastic model was developed for predicting stress given a certain strain history. The simple model showed good qualitative agreement with results of constant rate, uniaxial accurately predicting stresses for cyclic strain histories typical of balloon flights. A program was outlined which will result in the development of a more complex nonlinear viscoelastic model.

  16. Passivation Effects in Copper Thin Films

    SciTech Connect

    Wiederhirn, G.; Nucci, J.; Richter, G.; Arzt, E.; Balk, T. J.; Dehm, G.

    2006-02-07

    We studied the influence of a 10 nm AlxOy passivation on the stress-temperature behavior of 100 nm and 1 {mu}m thick Cu films. At low temperatures, the passivation induces a large tensile stress increase in the 100 nm film; however, its effect on the 1 {mu}m film is negligible. At high temperatures, the opposite behavior is observed; while the passivation does not change the 100 nm film behavior, it strengthens the 1 {mu}m film by driving it deeper into compression. These observations are explained in light of a combination of constrained diffusional creep and dislocation dynamics unique to ultra-thin films.

  17. Thin film photovoltaic device with multilayer substrate

    DOEpatents

    Catalano, Anthony W.; Bhushan, Manjul

    1984-01-01

    A thin film photovoltaic device which utilizes at least one compound semiconductor layer chosen from Groups IIB and VA of the Periodic Table is formed on a multilayer substrate The substrate includes a lowermost support layer on which all of the other layers of the device are formed. Additionally, an uppermost carbide or silicon layer is adjacent to the semiconductor layer. Below the carbide or silicon layer is a metal layer of high conductivity and expansion coefficient equal to or slightly greater than that of the semiconductor layer.

  18. Polydiacetylene thin films for nonlinear optical applications

    NASA Technical Reports Server (NTRS)

    Paley, Mark S.

    1993-01-01

    One very promising class of organic compounds for nonlinear optical (NLO) applications are polydiacetylenes, which are novel in that they are highly conjugated polymers which can also be crystalline. Polydiacetylenes offer several advantages over other organic materials: because of their highly conjugated electronic structures, they are capable of possessing large optical nonlinearities with fast response times; because they are crystalline, they can be highly ordered, which is essential for optimizing their NLO properties; and, last, because they are polymeric, they can be formed as thin films, which are useful for device fabrication. We have actively been carrying out ground-based research on several compounds of interest.

  19. Articles including thin film monolayers and multilayers

    SciTech Connect

    Li, DeQuan; Swanson, B.I.

    1992-12-31

    This invention pertains to thin film assemblies or devices useful as sensors, nonlinear optical materials, and trace material scavengers. It claims a base substrate having an oxide surface layer, and a multidentate ligand, capable of binding a metal ion, attached to the oxide surface layer of the base substrate. A metal species may be provided attached to the ligand, and a multifunctional organic ligand may be provided attached to the metal species. A second metal species may be provided attached to the multifunctional ligand.

  20. Thin film dielectric microstrip kinetic inductance detectors

    NASA Astrophysics Data System (ADS)

    Mazin, Benjamin A.; Sank, Daniel; McHugh, Sean; Lucero, Erik A.; Merrill, Andrew; Gao, Jiansong; Pappas, David; Moore, David; Zmuidzinas, Jonas

    2010-03-01

    Microwave kinetic inductance detectors, or MKIDs, are a type of low temperature detector that exhibit intrinsic frequency domain multiplexing at microwave frequencies. We present the first theory and measurements on a MKID based on a microstrip transmission line resonator. A complete characterization of the dielectric loss and noise properties of these resonators is performed, and agrees well with the derived theory. A competitive noise equivalent power of 5×10-17 W Hz-1/2 at 10 Hz has been demonstrated. The resonators exhibit the highest quality factors known in a microstrip resonator with a deposited thin film dielectric.

  1. Thin-Film Photovoltaic Device Fabrication

    NASA Technical Reports Server (NTRS)

    Scofield, John H.

    2003-01-01

    This project will primarily involve the fabrication and characterization of thin films and devices for photovoltaic applications. The materials involved include Il-VI materials such as zinc oxide, cadmium sulfide, and doped analogs. The equipment ot be used will be sputtering and physical evaporations. The types of characterization includes electrical, XRD, SEM and CV and related measurements to establish the efficiency of the devices. The faculty fellow will be involved in a research team composed of NASA and University researchers as well as students and other junior researchers.

  2. Rigid thin windows for vacuum applications

    DOEpatents

    Meyer, Glenn Allyn; Ciarlo, Dino R.; Myers, Booth Richard; Chen, Hao-Lin; Wakalopulos, George

    1999-01-01

    A thin window that stands off atmospheric pressure is fabricated using photolithographic and wet chemical etching techniques and comprises at least two layers: an etch stop layer and a protective barrier layer. The window structure also comprises a series of support ribs running the width of the window. The windows are typically made of boron-doped silicon and silicon nitride and are useful in instruments such as electron beam guns and x-ray detectors. In an electron beam gun, the window does not impede the electrons and has demonstrated outstanding gun performance and survivability during the gun tube manufacturing process.

  3. Effective dynamics for ferromagnetic thin films

    SciTech Connect

    Garcia-Cervera, Carlos J.; E, Weinan

    2001-07-01

    In a ferromagnetic material, the dynamics of the relaxation process are affected by the presence of a strong shape or material anisotropy. In this article, we systematically explore this fact to derive the effective dynamical equation for a soft ferromagnetic thin film. We show that, as a consequence of the interplay between shape anisotropy and damping, the gyromagnetic term is effectively also a damping term for the in-plane components of the magnetization distribution. We validate our result through numerical simulation of the original Landau{endash}Lifshitz equation and our effective equation. {copyright} 2001 American Institute of Physics.

  4. Talbot holographic illumination nonscanning (THIN) fluorescence microscopy

    PubMed Central

    Tsai, Jui-Chang; Yu, Sung-Liang; Chen, Hsi-Hsun; Wong, Jau-Min; Matsudaira, Paul; So, Peter T. C.; Barbastathis, George

    2015-01-01

    Optical sectioning techniques offer the ability to acquire three-dimensional information from various organ tissues by discriminating between the desired in-focus and out-of-focus (background) signals. Alternative techniques to confocal, such as active structured illumination, exist for fast optically sectioned images, but they require individual axial planes to be imaged consecutively. In this article, an imaging technique (THIN), by utilizing active Talbot illumination in 3D and multiplexed holographic Bragg filters for depth discrimination, is demonstrated for imaging in vivo 3D biopsy without mechanical or optical axial scanning. PMID:25678936

  5. Study of iron mononitride thin films

    SciTech Connect

    Tayal, Akhil Gupta, Mukul Phase, D. M. Reddy, V. R. Gupta, Ajay

    2014-04-24

    In this work we have studied the crystal structural and local ordering of iron and nitrogen in iron mononitride thin films prepared using dc magnetron sputtering at sputtering power of 100W and 500W. The films were sputtered using pure nitrogen to enhance the reactivity of nitrogen with iron. The x-ray diffraction (XRD), conversion electron Mössbauer spectroscopy (CEMS) and soft x-ray absorption spectroscopy (SXAS) studies shows that the film crystallizes in ZnS-type crystal structure.

  6. Preface: Thin films of molecular organic materials

    NASA Astrophysics Data System (ADS)

    Fraxedas, J.

    2008-03-01

    This special issue is devoted to thin films of molecular organic materials and its aim is to assemble numerous different aspects of this topic in order to reach a wide scientific audience. Under the term 'thin films', structures with thicknesses spanning from one monolayer or less up to several micrometers are included. In order to narrow down this relaxed definition (how thin is thin?) I suggest joining the stream that makes a distinction according to the length scale involved, separating nanometer-thick films from micrometer-thick films. While the physical properties of micrometer-thick films tend to mimic those of bulk materials, in the low nanometer regime new structures (e.g., crystallographic and substrate-induced phases) and properties are found. However, one has to bear in mind that some properties of micrometer-thick films are really confined to the film/substrate interface (e.g. charge injection), and are thus of nanometer nature. Supported in this dimensionality framework, this issue covers the most ideal and model 0D case, a single molecule on a surface, through to the more application-oriented 3D case, placing special emphasis on the fascinating 2D domain that is monolayer assembly. Thus, many aspects will be reviewed, such as single molecules, self-organization, monolayer regime, chirality, growth, physical properties and applications. This issue has been intentionally restricted to small molecules, thus leaving out polymers and biomolecules, because for small molecules it is easier to establish structure--property relationships. Traditionally, the preparation of thin films of molecular organic materials has been considered as a secondary, lower-ranked part of the more general field of this class of materials. The coating of diverse surfaces such as silicon, inorganic and organic single crystals, chemically modified substrates, polymers, etc., with interesting molecules was driven by the potential applications of such molecular materials

  7. Sensitive detection of NMR for thin films.

    PubMed

    Lee, Soonchil

    2015-10-01

    NMR can provide valuable information about thin films, but its relatively low sensitivity allows data acquisition only from bulk samples. The sensitivity problem is circumvented by detection schemes with higher sensitivity and/or enhanced polarization. In most of these ingenious techniques, electrons play a central role through hyperfine interactions with the nuclei of interest or the conversion of the spin orientation to an electric charge. The state of the art in NMR is the control of a single nuclear spin state, the complete form of which is one of the ultimate goals of nanotechnology. PMID:26549846

  8. Stable localized patterns in thin liquid films

    NASA Technical Reports Server (NTRS)

    Deissler, Robert J.; Oron, Alexander

    1992-01-01

    A two-dimensional nonlinear evolution equation is studied which describes the three-dimensional spatiotemporal behavior of the air-liquid interface of a thin liquid film lying on the underside of a cooled horizontal plate. It is shown that the equation has a Liapunov functional, and this fact is exploited to demonstrate that the Marangoni effect can stabilize the destabilizing effect of gravity (the Rayleigh-Taylor instability), allowing for the existence of stable localized axisymmetric solutions for a wide range of parameter values. Various properties of these structures are discussed.

  9. High-energy regenerative thin disk amplifier

    NASA Astrophysics Data System (ADS)

    Chyla, Michal; Smrz, Martin; Mocek, Tomas

    2012-07-01

    Design of a compact regenerative laser amplifier based on two Yb:YAG thin-disks is presented. Energy up to 100 mJ in picoseconds pulses will be delivered with a repetition rate of 1 kHz. System is designed for seeding a kW-class multipass amplifier for industrial and scientific applications. Laser heads are pumped at zero-phonon line (968.825 nm [1]) by stabilized high-power pump diodes operated in pulsed regime. Seed pulses are produced in a fiber oscillator at 1030 nm and CPA technique utilizing transmission gratings for pulse stretching and compression is applied.

  10. Study of microstructure and electroluminescence of zinc sulfide thin film

    NASA Astrophysics Data System (ADS)

    Zhao-hong, Liu; Yu-jiang, Wang; Mou-zhi, Chen; Zhen-xiang, Chen; Shu-nong, Sun; Mei-chun, Huang

    1998-03-01

    The electroluminscent zinc sulfide thin film doped with erbium, fabricated by thermal evaporation with two boats, are examined. The surface and internal electronic states of ZnS thin film are measured by means of x-ray diffraction and x-ray photoemission spectroscopy. The information on the relations between electroluminescent characteristics and internal electronic states of the film is obtained. And the effects of the microstructure of thin film doped with rare earth erbium on electroluminescence are discussed as well.

  11. Methods for making thin layers of crystalline materials

    DOEpatents

    Lagally, Max G; Paskiewicz, Deborah M; Tanto, Boy

    2013-07-23

    Methods for making growth templates for the epitaxial growth of compound semiconductors and other materials are provided. The growth templates are thin layers of single-crystalline materials that are themselves grown epitaxially on a substrate that includes a thin layer of sacrificial material. The thin layer of sacrificial material, which creates a coherent strain in the single-crystalline material as it is grown thereon, includes one or more suspended sections and one or more supported sections.

  12. Porous Organic Cage Thin Films and Molecular-Sieving Membranes.

    PubMed

    Song, Qilei; Jiang, Shan; Hasell, Tom; Liu, Ming; Sun, Shijing; Cheetham, Anthony K; Sivaniah, Easan; Cooper, Andrew I

    2016-04-01

    Porous organic cage molecules are fabricated into thin films and molecular-sieving membranes. Cage molecules are solution cast on various substrates to form amorphous thin films, with the structures tuned by tailoring the cage chemistry and processing conditions. For the first time, uniform and pinhole-free microporous cage thin films are formed and demonstrated as molecular-sieving membranes for selective gas separation. PMID:26800019

  13. Overview and Challenges of Thin Film Solar Electric Technologies

    SciTech Connect

    Ullal, H. S.

    2008-12-01

    In this paper, we report on the significant progress made worldwide by thin-film solar cells, namely, amorphous silicon (a-Si), cadmium telluride (CdTe), and copper indium gallium diselenide (CIGS). Thin-film photovoltaic (PV) technology status is also discussed in detail. In addition, R&D and technology challenges in all three areas are elucidated. The worldwide estimated projection for thin-film PV technology production capacity announcements are estimated at more than 5000 MW by 2010.

  14. Form Birefringence in Thin Films with Oblique Columnar Structures

    NASA Astrophysics Data System (ADS)

    Wang, Jian-Guo; Shao, Jian-Da; Wang, Su-Mei; He, Hong-Bo; Fan, Zheng-Xiu

    2005-08-01

    Effective medium theory is useful for designing optical elements with form birefringent subwavelength structures. Thin films fabricated by oblique deposition are similar to the two-dimensional surface relief subwavelength gratings. We use the effective medium theory to calculate the anisotropic optical properties of the thin films with oblique columnar structures. The effective refractive indices and the directions are calculated from effective medium theory. It is shown that optical thin films with predetermined refractive indices and birefringence may be engineered.

  15. Thin Dielectric Films Containing Tb{sup 3+} Ions For Application In Thin Film Solar Cells

    SciTech Connect

    Sendova-Vassileva, M.; Angelov, O.; Dimova-Malmovska, D.; Baumgartner, K.; Carius, R.; Hollaender, B.

    2010-01-21

    Thin transparent dielectric films containing Tb{sup 3+} are developed for application as spectral converters of the solar spectrum in thin film silicon solar cells. The results on the deposition and characterization of thin SiO{sub 2} and Al{sub 2}O{sub 3} films containing Tb{sup 3+} ions are presented. The films are prepared by RF magnetron co-sputtering, a well established technique for large area coatings. Photoluminescence (PL) is measured at room temperature, using the 488 nm line of an Ar laser and a nitrogen-cooled CCD camera attached to a monochromator. The dependence of the PL intensity on the concentration of Tb in the film is studied. It is found that the intensity exhibits a maximum at about 1 at.%. Annealing studies are performed on SiO{sub 2}:Tb with two different methods to improve the PL intensity. In both regimes of annealing, the best results for thin SiO{sub 2}:Tb films are obtained in the temperature range of 650-700 deg. C. After treatment at this temperature the Tb PL increases 2.5-3 times.

  16. Thin Dielectric Films Containing Tb3+ Ions For Application In Thin Film Solar Cells

    NASA Astrophysics Data System (ADS)

    Sendova-Vassileva, M.; Baumgartner, K.; Angelov, O.; Holländer, B.; Dimova-Malmovska, D.; Carius, R.

    2010-01-01

    Thin transparent dielectric films containing Tb3+ are developed for application as spectral converters of the solar spectrum in thin film silicon solar cells. The results on the deposition and characterization of thin SiO2 and Al2O3 films containing Tb3+ ions are presented. The films are prepared by RF magnetron co-sputtering, a well established technique for large area coatings. Photoluminescence (PL) is measured at room temperature, using the 488 nm line of an Ar laser and a nitrogen-cooled CCD camera attached to a monochromator. The dependence of the PL intensity on the concentration of Tb in the film is studied. It is found that the intensity exhibits a maximum at about 1 at.%. Annealing studies are performed on SiO2:Tb with two different methods to improve the PL intensity. In both regimes of annealing, the best results for thin SiO2:Tb films are obtained in the temperature range of 650-700° C. After treatment at this temperature the Tb PL increases 2.5-3 times.

  17. Dye-Sensitization Of Nanocrystalline ZnO Thin Films

    NASA Astrophysics Data System (ADS)

    Ajimsha, R. S.; Tyagi, M.; Das, A. K.; Misra, P.; Kukreja, L. M.

    2010-12-01

    Nannocrystalline and nanoporus thin films of ZnO were synthesized on glass substrates by using wet chemical drop casting method. X-ray diffraction measurements on these samples confirmed the formation of ZnO nanocrystallites in hexagonal wurtzite phase with mean size of ˜20 nm. Photo sensitization of these nanostructured ZnO thin films was carried out using three types of dyes Rhodamine 6 G, Chlorophyll and cocktail of Rhodamine 6 G and Chlorophyll in 1:1 ratio. Dye sensitized ZnO thin films showed enhanced optical absorption in visible spectral region compared to the pristine ZnO thin films.

  18. Uncooled thin film pyroelectric IR detector with aerogel thermal isolation

    DOEpatents

    Ruffner, Judith A.; Bullington, Jeff A.; Clem, Paul G.; Warren, William L.; Brinker, C. Jeffrey; Tuttle, Bruce A.; Schwartz, Robert W.

    1999-01-01

    A monolithic infrared detector structure which allows integration of pyroelectric thin films atop low thermal conductivity aerogel thin films. The structure comprises, from bottom to top, a substrate, an aerogel insulating layer, a lower electrode, a pyroelectric layer, and an upper electrode layer capped by a blacking layer. The aerogel can offer thermal conductivity less than that of air, while providing a much stronger monolithic alternative to cantilevered or suspended air-gap structures for pyroelectric thin film pixel arrays. Pb(Zr.sub.0.4 Ti.sub.0.6)O.sub.3 thin films deposited on these structures displayed viable pyroelectric properties, while processed at 550.degree. C.

  19. High average power scaleable thin-disk laser

    DOEpatents

    Beach, Raymond J.; Honea, Eric C.; Bibeau, Camille; Payne, Stephen A.; Powell, Howard; Krupke, William F.; Sutton, Steven B.

    2002-01-01

    Using a thin disk laser gain element with an undoped cap layer enables the scaling of lasers to extremely high average output power values. Ordinarily, the power scaling of such thin disk lasers is limited by the deleterious effects of amplified spontaneous emission. By using an undoped cap layer diffusion bonded to the thin disk, the onset of amplified spontaneous emission does not occur as readily as if no cap layer is used, and much larger transverse thin disks can be effectively used as laser gain elements. This invention can be used as a high average power laser for material processing applications as well as for weapon and air defense applications.

  20. Corrections to the thin wall approximation in general relativity

    NASA Technical Reports Server (NTRS)

    Garfinkle, David; Gregory, Ruth

    1989-01-01

    The question is considered whether the thin wall formalism of Israel applies to the gravitating domain walls of a lambda phi(exp 4) theory. The coupled Einstein-scalar equations that describe the thick gravitating wall are expanded in powers of the thickness of the wall. The solutions of the zeroth order equations reproduce the results of the usual Israel thin wall approximation for domain walls. The solutions of the first order equations provide corrections to the expressions for the stress-energy of the wall and to the Israel thin wall equations. The modified thin wall equations are then used to treat the motion of spherical and planar domain walls.