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Sample records for alcator device

  1. Comparison of tungsten nano-tendrils grown in Alcator C-Mod and linear plasma devices

    NARCIS (Netherlands)

    Wright, G. M.; D. Brunner,; Baldwin, M. J.; Bystrov, K.; Doerner, R. P.; Labombard, B.; Lipschultz, B.; De Temmerman, G.; J.L. Terry,; Whyte, D. G.; Woller, K.B.

    2013-01-01

    Growth of tungsten nano-tendrils (“fuzz”) has been observed for the first time in the divertor region of a high-power density tokamak experiment. After 14 consecutive helium L-mode discharges in Alcator C-Mod, the tip of a tungsten Langmuir probe at the outer strike point was fully covered with a la

  2. Numerical modeling of a fast-neutron collimator for the Alcator A fusion device

    International Nuclear Information System (INIS)

    A numerical procedure is developed to analyze neutron collimators used for spatial neutron measurements of plasma neutrons. The procedure is based upon Monte-Carlo methods and uses a standard Monte-Carlo code. The specific developments described herein involve a new approach to represent complex spatial details in a method that is conservative of computer time, retains accuracy and required only modest changes in already-developed Monte-Carlo procedures. The procedure was used to model the Alcator A collimator. The collimator consists of 448 cells and has a measured spatial point source response of 0.7 cm. The numerical procedure successfully predicts this response

  3. Alcator C-MOD proposal addendum

    International Nuclear Information System (INIS)

    Since the design concept and overall purpose of the Alcator C-MOD device are similar to that proposed in October 1985, we have chosen in this document only to highlight areas where changes or additions have been made. Chapters in the Addendum correspond to those in the Proposal, except Chapter 9 which describes a number of toroidal improvement concepts which are being considered for inclusion in the Alcator C-MOD experimental program. A description of the redesign and a discussion of the objectives of the experimental program are given

  4. Alcator C-MOD final safety analysis

    International Nuclear Information System (INIS)

    This document is designed to address the safety issues involved with the Alcator C-Mod project. This report will begin with a brief description of the experimental objectives which will be followed by information concerning the site. The Alcator C-Mod experiment is a pulsed fusion experiment in which a plasma formed from small amounts of hydrogen or deuterium gas is confined in a magnetic field for short periods (∼1 s). No radioactive fuels or fissile materials are used in the device, so that no criticality hazard exists and no credible nuclear accident can occur. During deuterium operation, the production of a small number of neutrons from a short pulse could result in a small amount of short- and intermediate-lived radioactive isotopes being produced inside the experimental cell. This report will demonstrate that this does not pose an additional hazard to the general population. The health and safety hazards resulting from Alcator C-Mod occur to the workers on the experiment, each of which is described in its own chapter with the steps taken to minimize the risk to employees. These hazards include fire, chemicals and cryogenics, air quality, electrical, electromagnetic radiation, ionizing radiation, and mechanical and natural phenomena. None of these hazards is unique to the facility, and methods of protection from them are well defined and are discussed in the chapter which describes each hazard. The quality assurance program, critical to ensuring the safety aspects of the program, will also be described

  5. Alcator C-Mod: A high-field divertor tokamak

    Science.gov (United States)

    Lipschultz, B.; Becker, H.; Bonoli, P.; Coleman, J.; Fiore, C.; Golovato, S.; Granetz, R.; Greenwald, M.; Gwinn, D.; Humphries, D.; Hutchinson, I.; Irby, J.; Marmar, E.; Montgomery, D. B.; Najmabadi, F.; Parker, R.; Porkolab, M.; Rice, J.; Sevillano, E.; Takase, Y.; Terry, J.; Watterson, R.; Wolfe, S.

    1989-04-01

    The Alcator C-Mod tokamak is a new device presently under construction at Massachusetts Institute of Technology (M.I.T.) which is scheduled to begin operation in mid-1990. The projected operating parameters are as follows: Toroidal field of 9 T; Ip ≤ 3 MA, R = 66.5 cm, a = 21 cm, κ ≤ 2.0, δ ≤ 0.5, ne ≤ 10 21m-3, PICRF ≤ 6 MW. The divertor configuration includes mechanical baffling as opposed to an 'open' geometry. Under strictly ohmic heating conditions, central Ti and Te are predicted to be in the range 2.5-3.5 keV over the density range (4-8) × 10 20m-3. With the addition of 6 MW of ICRF heating, Ti should vary from 4-8 keV over the same density range (assuming either Kaye-Goldston or Neo-Alcator scalings for electron confinement). Based on edge plasma characterizations from Alcator-C and divertor tokamaks, the scrape-off layer (SOL) properties are predicted to be: λn ≈ 10mm, density at the divertor plate < 2 × 10 21m-3, H 0 ionization mean free path between 1 and 10 mm. Maximum heat loads on various internal components are predicted to be in the range 5-10 MW/m 2. The flexibility of the poloidal field system in forming a number of flux surface geometries will provide further comparisons of the relative impurity control capabilities of double-null, single-null and limiter plasmas.

  6. Neutral particle dynamics in the Alcator C-Mod tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Niemczewski, A.P.

    1995-08-01

    This thesis presents an experimental study of neutral particle dynamics in the Alcator C-Mod tokamak. The primary diagnostic used is a set of six neutral pressure gauges, including special-purpose gauges built for in situ tokamak operation. While a low main chamber neutral pressure coincides with high plasma confinement regimes, high divertor pressure is required for heat and particle flux dispersion in future devices such as ITER. Thus we examine conditions that optimize divertor compression, defined here as a divertor-to-midplane pressure ratio. We find both pressures depend primarily on the edge plasma regimes defined by the scrape-off-layer heat transport. While the maximum divertor pressure is achieved at high core plasma densities corresponding to the detached divertor state, the maximum compression is achieved in the high-recycling regime. Variations in the divertor geometry have a weaker effect on the neutral pressures. For otherwise similar plasmas the divertor pressure and compression are maximum when the strike point is at the bottom of the vertical target plate. We introduce a simple flux balance model, which allows us to explain the divertor neutral pressure across a wide range of plasma densities. In particular, high pressure sustained in the detached divertor (despite a considerable drop in the recycling source) can be explained by scattering of neutrals off the cold plasma plugging the divertor throat. Because neutrals are confined in the divertor through scattering and ionization processes (provided the mean-free-paths are much shorter than a typical escape distance) tight mechanical baffling is unnecessary. The analysis suggests that two simple structural modifications may increase the divertor compression in Alcator C-Mod by a factor of about 5. Widening the divertor throat would increase the divertor recycling source, while closing leaks in the divertor structure would eliminate a significant neutral loss mechanism. 146 refs., 82 figs., 14 tabs.

  7. Critical need for MFE: the Alcator DX advanced divertor test facility

    Science.gov (United States)

    Vieira, R.; Labombard, B.; Marmar, E.; Irby, J.; Wolf, S.; Bonoli, P.; Fiore, C.; Granetz, R.; Greenwald, M.; Hutchinson, I.; Hubbard, A.; Hughes, J.; Lin, Y.; Lipschultz, B.; Parker, R.; Porkolab, M.; Reinke, M.; Rice, J.; Shiraiwa, S.; Terry, J.; Theiler, C.; Wallace, G.; White, A.; Whyte, D.; Wukitch, S.

    2013-10-01

    Three critical challenges must be met before a steady-state, power-producing fusion reactor can be realized: how to (1) safely handle extreme plasma exhaust power, (2) completely suppress material erosion at divertor targets and (3) do this while maintaining a burning plasma core. Advanced divertors such as ``Super X'' and ``X-point target'' may allow a fully detached, low temperature plasma to be produced in the divertor while maintaining a hot boundary layer around a clean plasma core - a potential game-changer for magnetic fusion. No facility currently exists to test these ideas at the required parallel heat flux densities. Alcator DX will be a national facility, employing the high magnetic field technology of Alcator combined with high-power ICRH and LHCD to test advanced divertor concepts at FNSF/DEMO power exhaust densities and plasma pressures. Its extended vacuum vessel contains divertor cassettes with poloidal field coils for conventional, snowflake, super-X and X-point target geometries. Divertor and core plasma performance will be explored in regimes inaccessible in conventional devices. Reactor relevant ICRF and LH drivers will be developed, utilizing high-field side launch platforms for low PMI. Alcator DX will inform the conceptual development and accelerate the readiness-for-deployment of next-step fusion facilities.

  8. First results from Alcator-C-MOD

    Energy Technology Data Exchange (ETDEWEB)

    Hutchinson, I.H.; Boivin, R.; Bombarda, F.; Bonoli, P.; Fairfax, S.; Fiore, C.; Goetz, J.; Golovato, S.; Granetz, R.; Greenwald, M.; Horne, S.; Hubbard, A.; Irby, J.; LaBombard, B.; Lipschultz, B.; Marmar, E.; McCracken, G.; Porkolab, M.; Rice, J.; Snipes, J.; Takase, Y.; Terry, J.; Wolfe, S.; Christensen, C.; Garnier, D.; Graf, M.; Hsu, T.; Luke, T.; May, M.; Niemczewski, A.; Tinios, G.; Schachter, J.; Urbahn, J. (Plasma Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States))

    1994-05-01

    Early operation of the Alcator-C-MOD tokamak [I.H. Hutchinson, [ital Proceedings] [ital of] [ital IEEE] 13[ital th] [ital Symposium] [ital on] [ital Fusion] [ital Engineering], Knoxville, TN, edited by M. Lubell, M. Nestor, and S. Vaughan (Institute of Electrical and Electronic Engineers, New York, 1990), Vol. 1, p. 13] is surveyed. Reliable operation, with plasma current up to 1 MA, has been obtained, despite the massive conducting superstructure and the associated error fields. However, vertical disruptions are not slowed by the long vessel time constant. With pellet fueling, peak densities up to 9[times]10[sup 20] m[sup [minus]3] have been attained and snakes'' are often seen. Initial characterization of divertor and scrape-off layer is presented and indicates approximately Bohm diffusion. The edge plasma shows a wealth of marfe-like phenomena, including a transition to detachment from the divertor plates with accompanying radiative divertor regions. Energy confinement generally appears to exceed the expectations of neo-Alcator scaling. A transition to Ohmic H mode has been observed. Ion cyclotron heating experiments have demonstrated good power coupling, in agreement with theory.

  9. Transport experiments in Alcator-C-Mod

    Energy Technology Data Exchange (ETDEWEB)

    Greenwald, M.; Boivin, R.L.; Bonoli, P.; Christensen, C.; Fiore, C.; Garnier, D.; Goetz, J.; Golovato, S.; Graf, M.; Granetz, R.; Horne, S.; Hsu, T.; Hubbard, A.; Hutchinson, I.; Irby, J.; Kurz, C.; LaBombard, B.; Lipschultz, B.; Luke, T.; Marmar, E.; McCracken, G.; Niemczewski, A.; O`Shea, P.; Porkolab, M.; Rice, J.; Reardon, J.; Schachter, J.; Snipes, J.; Stek, P.; Takase, Y.; Terry, J.; Umansky, M.; Watterson, R.; Wolfe, S. [Plasma Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Bombarda, F. [ENEA-Frascati, Frascati (Italy); May, M. [Johns Hopkins University, Baltimore, Maryland 21218 (United States); Welch, B. [University of Maryland, College Park, Maryland 20742 (United States)

    1995-06-01

    A series of transport experiments has been carried out in Alcator-C-Mod. [Phys Plasmas {bold 1}, 1511 (1994)]. Data from both Ohmic and ICRF (ion cyclotron range of frequencies) heated plasmas can be fitted with an L-mode (low mode) scaling law. The Ohmic {tau}{sub {ital E}}`s show no scaling with density in any regime and can reach values of 2--3 times neo-Alcator. Impurity confinement has been studied with the laser blow-off technique with {tau}{sub {ital I}} showing nearly linear scaling with plasma current. Ohmic and ICRF H modes are obtained over a wide range of discharge parameters, extending the range in the international database for {ital nB}, by almost a factor of 10. The power threshold for ELM-free (edge localized mode) discharges is in rough agreement with the scaling {ital P}/{ital S}=0.044{ital nB}. Energy diffusivities of Ohmic and ICRF heated plasmas have been measured from local analysis of plasma profiles and power fluxes. The same analysis produces a value for plasma resistivity which lies between the Spitzer and neoclassical calculations. Analysis of plasma transients have yielded values for particle diffusivity and convection velocity.

  10. Simulated plasma facing component measurements for an in situ surface diagnostic on Alcator C-Moda)

    Science.gov (United States)

    Hartwig, Z. S.; Whyte, D. G.

    2010-10-01

    The ideal in situ plasma facing component (PFC) diagnostic for magnetic fusion devices would perform surface element and isotope composition measurements on a shot-to-shot (˜10 min) time scale with ˜1 μm depth and ˜1 cm spatial resolution over large areas of PFCs. To this end, the experimental adaptation of the customary laboratory surface diagnostic—nuclear scattering of MeV ions—to the Alcator C-Mod tokamak is being guided by ACRONYM, a Geant4 synthetic diagnostic. The diagnostic technique and ACRONYM are described, and synthetic measurements of film thickness for boron-coated PFCs are presented.

  11. High gain free electron laser for heating and current drive in the ALCATOR-C tokamak

    International Nuclear Information System (INIS)

    The free electron laser (FEL) particle simulation code, FRED, has been used to examine the design of an FEL for amplifying radiation in the one to two millimeter wavelength range for use in electron heating and current drive in a tokamak device such as ALCATOR-C. As a desired design goal a peak output power of 8 GW, with a minimum input power in the 1 to 100 watt range has been used. The effects of electron beam current, energy and brightness, laser frequency and input power as well as wiggler wavelength and overall wiggler length on the performance of the FEL have been examined

  12. Axisymmetric Control in Alcator C-Mod

    Science.gov (United States)

    Tinios, Gerasimos

    1995-01-01

    This thesis investigates the degree to which linear axisymmetric modeling of the response of a tokamak plasma can reproduce observed experimental behavior. The emphasis is on the vertical instability. The motivation for this work lies in the fact that, once dependable models have been developed, modern control theory methods can be used to design feedback laws for more effective and efficient tokamak control. The models are tested against experimental data from the Alcator C-Mod tokamak. A linear model for each subsystem of the closed-loop system constituting an Alcator C-Mod discharge under feedback control has been constructed. A non-rigid, approximately flux-conserving, perturbed equilibrium plasma response model is used in the comparison to experiment. A detailed toroidally symmetric model of the vacuum vessel and the supporting superstructure is used. Modeling of the power supplies feeding the active coils has been included. Experiments have been conducted with vertically unstable plasmas where the feedback was turned off and the plasma response was observed in an open -loop configuration. The closed-loop behavior has been examined by injecting step perturbations into the desired vertical position of the plasma. The agreement between theory and experiment in the open-loop configuration was very satisfactory, proving that the perturbed equilibrium plasma response model and a toroidally symmetric electromagnetic model of the vacuum vessel and the structure can be trusted for the purpose of calculations for control law design. When the power supplies and the feedback computer hardware are added to the system, however, as they are in the closed-loop configuration, they introduce nonlinearities that make it difficult to explain observed behavior with linear theory. Nonlinear simulation of the time evolution of the closed-loop experiments was able to account for the discrepancies between linear theory and experiment. (Copies available exclusively from MIT Libraries

  13. Nonaxisymmetric field effects on Alcator C-Moda)

    Science.gov (United States)

    Wolfe, S. M.; Hutchinson, I. H.; Granetz, R. S.; Rice, J.; Hubbard, A.; Lynn, A.; Phillips, P.; Hender, T. C.; Howell, D. F.; La Haye, R. J.; Scoville, J. T.

    2005-05-01

    A set of external coils (A-coils) capable of producing nonaxisymmetric, predominantly n =1, fields with different toroidal phase and a range of poloidal mode m spectra has been used to determine the threshold amplitude for mode locking over a range of plasma parameters in Alcator C-Mod [I. H. Hutchinson, R. Boivin, F. Bombarda, P. Bonoli, S. Fairfax, C. Fiore, J. Goetz, S. Golovato, R. Granetz, M. Greenwald et al., Phys. Plasmas 1, 1511 (1994)]. The threshold perturbations and parametric scalings, expressed in terms of (B21/BT), are similar to those observed on larger, lower field devices. The threshold is roughly linear in density, with typical magnitudes of order 10-4. This result implies that locked modes should not be significantly more problematic for the International Thermonuclear Experimental Reactor [I. P. B. Editors, Nucl. Fusion 39, 2286 (1999)] than for existing devices. Coordinated nondimensional identity experiments on the Joint European Torus [Fusion Technol. 11, 13 (1987)], DIII-D [Fusion Technol. 8, 441 (1985)], and C-Mod, with matching applied mode spectra, have been carried out to determine more definitively the field and size scalings. Locked modes on C-Mod are observed to result in braking of core toroidal rotation, modification of sawtooth activity, and significant reduction in energy and particle confinement, frequently leading to disruptions. Intrinsic error fields inferred from the threshold studies are found to be consistent in amplitude and phase with a comprehensive model of the sources of field errors based on "as-built" coil and bus-work details and coil imperfections inferred from measurements using in situ magnetic diagnostics on dedicated test pulses. Use of the A-coils to largely cancel the 2/1 component of the intrinsic nonaxisymmetric field has led to expansion of the accessible operating space in C-Mod, including operation up to 2 MA plasma current at 8 T.

  14. Diamagnetic measurements on the Alcator C tokamak

    International Nuclear Information System (INIS)

    A procedure for determining the total thermal energy content of a magnetically confined plasma from a measurement of the plasma magnetization has been successfully implemented on the Alcator C tokamak. When a plasma is confined by a magnetic field, the kinetic pressure of the plasma is supported by an interaction between the confining magnetic field and drift currents which flow in the plasma. These drift currents induce an additional magnetic field which can be measured by means of appropriately positioned pickup coils. From a measurement of this magnetic field and of the confining magnetic field, one can calculate the spatially averaged plasma pressure, which is related to the thermal energy content of the plasma by the equation of state of the plasma. The theory on which this measurement is based is described in detail. The fields and currents which flow in the plasma are related to the confining magnetic field and the plasma pressure by requiring that the plasma be in equilibrium, i.e., by balancing the forces due to pressure gradients against those due to magnetic interactions. The apparatus used to make this measurement is described and some example data analyses are carried out

  15. LPS impairs oxygen utilization in epithelia by triggering degradation of the mitochondrial enzyme Alcat1.

    Science.gov (United States)

    Zou, Chunbin; Synan, Matthew J; Li, Jin; Xiong, Sheng; Manni, Michelle L; Liu, Yuan; Chen, Bill B; Zhao, Yutong; Shiva, Sruti; Tyurina, Yulia Y; Jiang, Jianfei; Lee, Janet S; Das, Sudipta; Ray, Anuradha; Ray, Prabir; Kagan, Valerian E; Mallampalli, Rama K

    2016-01-01

    Cardiolipin (also known as PDL6) is an indispensable lipid required for mitochondrial respiration that is generated through de novo synthesis and remodeling. Here, the cardiolipin remodeling enzyme, acyl-CoA:lysocardiolipin-acyltransferase-1 (Alcat1; SwissProt ID, Q6UWP7) is destabilized in epithelia by lipopolysaccharide (LPS) impairing mitochondrial function. Exposure to LPS selectively decreased levels of carbon 20 (C20)-containing cardiolipin molecular species, whereas the content of C18 or C16 species was not significantly altered, consistent with decreased levels of Alcat1. Alcat1 is a labile protein that is lysosomally degraded by the ubiquitin E3 ligase Skp-Cullin-F-box containing the Fbxo28 subunit (SCF-Fbxo28) that targets Alcat1 for monoubiquitylation at residue K183. Interestingly, K183 is also an acetylation-acceptor site, and acetylation conferred stability to the enzyme. Histone deacetylase 2 (HDAC2) interacted with Alcat1, and expression of a plasmid encoding HDAC2 or treatment of cells with LPS deacetylated and destabilized Alcat1, whereas treatment of cells with a pan-HDAC inhibitor increased Alcat1 levels. Alcat1 degradation was partially abrogated in LPS-treated cells that had been silenced for HDAC2 or treated with MLN4924, an inhibitor of Cullin-RING E3 ubiquitin ligases. Thus, LPS increases HDAC2-mediated Alcat1 deacetylation and facilitates SCF-Fbxo28-mediated disposal of Alcat1, thus impairing mitochondrial integrity. PMID:26604221

  16. Disruptions and halo currents in Alcator C-Mod

    Science.gov (United States)

    Granetz, R. S.; Hutchinson, I. H.; Sorci, J.; Irby, J. H.; La Bombard, B.; Gwinn, D.

    1996-05-01

    Disruptions in Alcator C-Mod can generate large eddy currents in the highly conducting vacuum vessel and internal structures, including a significant poloidal component due to halo currents. In order to understand better the stresses arising from the resulting J*B forces, Alcator C-Mod has been fitted with a comprehensive set of sensors to measure the spatial distribution and temporal behaviour of the halo currents. It is found that they are toroidally asymmetric, with a typical peaking factor of 2. The asymmetric pattern usually rotates toroidally at a few kilohertz, thus ruling out first wall non-uniformities as the cause of the asymmetry. Analysis of the information compiled in the C-Mod disruption database indicates that the maximum halo current during a disruption scales roughly as either Ip2/Bphi or Ip/q95, but that there is a large amount of variation that is not yet understood

  17. The physics and engineering of Alcator C-Mod

    International Nuclear Information System (INIS)

    Alcator C-Mod is a new tokamak under construction at M.I.T. that promises to play an important and flexible role in the international fusion research effort. The physics and engineering features of the tokamak are described, giving an overview of the machine and plasma configurations. On the basis of empirical scaling laws, we predict the plasma confinement performance to be near DT equivalent breakeven. The planned experimental program is addressed to many of the vital physics questions still uncertain in high-performance tokamak plasma behaviour as well as to the investigation of innovative approaches to tokamak improvement. 17 refs., 17 figs., 3 tabs

  18. Divertor bypass in the Alcator C-Mod tokamak

    Science.gov (United States)

    Pitcher, C. S.; LaBombard, B.; Danforth, R.; Pina, W.; Silveira, M.; Parkin, B.

    2001-01-01

    The Alcator C-Mod divertor bypass has for the first time allowed in situ variations to the mechanical baffle design in a tokamak. The design utilizes small coils which interact with the ambient magnetic field inside the vessel to provide the torque required to control small flaps of a Venetian blind geometry. Plasma physics experiments with the bypass have revealed the importance of the divertor baffling to maintain high divertor gas pressures. These experiments have also indicated that the divertor baffling has only a limited effect on the main chamber pressure in C-Mod.

  19. Theoretical studies of lower hybrid current drive in the Alcator C tokamak

    International Nuclear Information System (INIS)

    Theoretical studies of lower hybrid current drive in the Alcator C tokamak using a simulation model is presented, the model incorporates a 1-D radial transport code to solve for the time evolution of the bulk plasma quantities

  20. The development of an Omegratron plasma ion mass spectrometer for Alcator C-Mod

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, E.E. Jr.

    1993-05-01

    A new diagnostic device, the Omegatron Probe, has been developed to investigate relative impurity levels and impurity charge state distribution in the Alcator C-Mod Tokamak edge plasma. The Omegatron probe consists of two principal components, a ``front-end`` of independently biased grids, arranged in a gridded energy analyzer fashion and a large collection cavity. Particles enter the probe in a thin ``ribbon`` through a knife-edge slit. The grids provide a means to measure and control the parallel energy distribution of the ions. In the collection cavity, an oscillating electric field is applied perpendicularly to the ambient magnetic field. Ions whose cyclotron frequencies are resonant with this electric field oscillation will gain perpendicular energy and be collected. In this way, the probe can be operated in two modes: first, by fixing the potentials on the grids and sweeping frequencies to obtain a `` Z/m spectrum`` of ion species and second, by fixing the frequency and sweeping the grid potentials to obtain the distribution function of an individual impurity species. The Omegatron probe performed successfully in tests on a Hollow Cathode Discharge (HCD) linear plasma column. It obtained measurements of T{sub e} {approx} 5 eV, T{sub i} (H{sup +}) {approx} 2.0 {plus_minus} 0.2 eV, n{sub 0} {approx} 9 {times} 10{sup 15} m{sup {minus}3}, RMS potential fluctuation levels of {approximately} 0.5 {plus_minus} 0.05 {plus_minus} T{sub e}, and obtained ``Z/m`` spectra for the plasma ions (H{sup +}, H{sub 2}{sup +}, He{sup +}). Additional experiments confirmed the theoretical scalings of the f/{delta}f resolution with the applied electric field and magnetic field strengths. The instrument yielded an absolute level of resolution, f/{delta}f, of approximately 2.5 to 3 times the theoretical values. Finally, the results from the HCD are used to project operation on Alcator C-Mod.

  1. Overview of Alcator C-Mod Research

    Science.gov (United States)

    White, Anne

    2015-11-01

    Research on C-Mod supports next-step-devices: RF heating, current and flow drive, divertor/PMI physics, non-ELMing regimes with enhanced confinement, and disruption mitigation/runaway dynamics. Disruption mitigation experiments in MHD-unstable plasmas show MGI works equally well with and without locked modes. The L-I-mode threshold is found to be independent of magnetic field, opening an expanded operating range at high field. The toroidal and radial structure of power deposition of RF waves into the edge plasma has been systematically quantified, through the use of a unique set of fast time resolution edge diagnostics. Progress in understanding multi-channel core transport has been significant. Full-physics, ITG/TEM/ETG gyrokinetic simulations show that nonlinear cross-scale coupling enhances both ion and electron heat flux to match experiments, explaining the origin of electron heat flux and stiffness. Dynamic, passive measurements of the core rotation velocity profiles with X-ray imaging crystal spectroscopy show the direction of intrinsic rotation reversals depends on central safety factor, not on the magnetic shear. Design studies for ADX and SPARC are establishing the engineering, economics and physics for a fusion energy development path leveraging new superconducting magnet technologies. This work is supported by the US DOE under DE- FC02-99ER54512-CMOD.

  2. Soft x-ray tomography on the Alcator C tokamak

    International Nuclear Information System (INIS)

    A soft x-ray tomography experiment has been performed on the Alcator C tokamak. An 80-chord array of detectors consisting of miniature PIN photodiodes was used to obtain tomographic reconstructions of the soft x-ray emissivity function's poloidal cross-section. The detectors are located around the periphery of the plasma at one toroidal location (top and bottom ports) and are capable of yielding useful information over a wide range of plasma operating parameters and conditions. The reconstruction algorithm employed makes no assumption whatsoever about plasma rotation, position, or symmetry. Its performance was tested, and it was found to work well and to be fairly insensitive to estimated levels of random and systematic errors in the data

  3. Two dimensional radiated power diagnostics on Alcator C-Moda)

    Science.gov (United States)

    Reinke, M. L.; Hutchinson, I. H.

    2008-10-01

    The radiated power diagnostics for the Alcator C-Mod tokamak have been upgraded to measure two dimensional structure of the photon emissivity profile in order to investigate poloidal asymmetries in the core radiation. Commonly utilized unbiased absolute extreme ultraviolet (AXUV) diode arrays view the plasma along five different horizontal planes. The layout of the diagnostic set is shown and the results from calibrations and recent experiments are discussed. Data showing a significant, 30%-40%, inboard/outboard emissivity asymmetry during ELM-free H-mode are presented. The ability to use AXUV diode arrays to measure absolute radiated power is explored by comparing diode and resistive bolometer-based emissivity profiles for highly radiative L-mode plasmas seeded with argon. Emissivity profiles match in the core but disagree radially outward resulting in an underprediction of Prad of nearly 50% by the diodes compared to Prad determined using resistive bolometers.

  4. Divertor IR thermography on Alcator C-Moda)

    Science.gov (United States)

    Terry, J. L.; LaBombard, B.; Brunner, D.; Payne, J.; Wurden, G. A.

    2010-10-01

    Alcator C-Mod is a particularly challenging environment for thermography. It presents issues that will similarly face ITER, including low-emissivity metal targets, low-Z surface films, and closed divertor geometry. In order to make measurements of the incident divertor heat flux using IR thermography, the C-Mod divertor has been modified and instrumented. A 6° toroidal sector has been given a 2° toroidal ramp in order to eliminate magnetic field-line shadowing by imperfectly aligned divertor tiles. This sector is viewed from above by a toroidally displaced IR camera and is instrumented with thermocouples and calorimeters. The camera provides time histories of surface temperatures that are used to compute incident heat-flux profiles. The camera sensitivity is calibrated in situ using the embedded thermocouples, thus correcting for changes and nonuniformities in surface emissivity due to surface coatings.

  5. Modeling of Alcator C-Mod Divertor Baffling Experiments

    Energy Technology Data Exchange (ETDEWEB)

    D. P. Stotler; C. S. Pitcher; C. J. Boswell; T. K. Chung; B. LaBombard; B. Lipschultz; J. L. Terry; R. J. Kanzleiter

    2000-11-29

    A specific Alcator C-Mod discharge from the series of divertor baffling experiments is simulated with the DEGAS 2 Monte Carlo neutral transport code. A simple two-point plasma model is used to describe the plasma variation between Langmuir probe locations. A range of conductances for the bypass between the divertor plenum and the main chamber are considered. The experimentally observed insensitivity of the neutral current flowing through the bypass and of the D alpha emissions to the magnitude of the conductance is reproduced. The current of atoms in this regime is being limited by atomic physics processes and not the bypass conductance. The simulated trends in the divertor pressure, bypass current, and D alpha emission agree only qualitatively with the experimental measurements, however. Possible explanations for the quantitative differences are discussed.

  6. Edge Minority Heating Experiment in Alcator C-Mod

    Energy Technology Data Exchange (ETDEWEB)

    S.J. Zweben; J.L. Terry; P. Bonoli; R. Budny; C.S. Chang; C. Fiore; G. Schilling; S. Wukitch; J. Hughes; Y. Lin; R. Perkins; M. Porkolab; the Alcator C-Mod Team

    2005-03-25

    An attempt was made to control global plasma confinement in the Alcator C-Mod tokamak by applying ion cyclotron resonance heating (ICRH) power to the plasma edge in order to deliberately create a minority ion tail loss. In theory, an edge fast ion loss could modify the edge electric field and so stabilize the edge turbulence, which might then reduce the H-mode power threshold or improve the H-mode barrier. However, the experimental result was that edge minority heating resulted in no improvement in the edge plasma parameters or global stored energy, at least at power levels of radio-frequency power is less than or equal to 5.5 MW. A preliminary analysis of these results is presented and some ideas for improvement are discussed.

  7. ICRF heating antennas for Alcator C-Mod

    International Nuclear Information System (INIS)

    Initial ICRF coupling studies were performed successfully on the Alcator C-Mod tokamak with all-metallic first wall, using a radially movable single current strap (monopole) antenna. The plasma loading is 10-30 times the vacuum loading, which is sufficient to inject 2 MW of RF power through one two-strap (dipole) antenna. The observed loading is consistent with predictions of full-wave calculations. Up to 1 MW of RF power (antenna power density of > or approx. 10 MW/m2) has been injected into the C-Mod plasma with no increase in the fractional radiated power Prad/Pin. Definite signs of both ion and electron heating were observed at power levels of 0.4 MW and higher (PRF/POH > or approx. 0.3) in the D(H) minority heating regime. High power heating experiments with 4 MW of source power and two dipole antennas will begin in early 1994. (author)

  8. Correlation ECE diagnostic in Alcator C-Mod

    International Nuclear Information System (INIS)

    Correlation ECE (CECE) is a diagnostic technique that allows measurement of small amplitude electron temperature, Te, fluctuations through standard cross-correlation analysis methods. In Alcator C-Mod, a new CECE diagnostic has been installed[Sung RSI 2012], and interesting phenomena have been observed in various plasma conditions. We find that local Te fluctuations near the edge (ρ ~ 0:8) decrease across the linearto- saturated ohmic confinement transition, with fluctuations decreasing with increasing plasma density [Sung NF 2013], which occurs simultaneously with rotation reversals [Rice NF 2011]. Te fluctuations are also reduced across core rotation reversals with an increase of plasma density in RF heated L-mode plasmas, which implies that the same physics related to the reduction of Te fluctuations may be applied to both ohmic and RF heated L-mode plasmas. In I-mode plasmas, we observe the reduction of core Te fluctuations, which indicates changes of turbulence occur not only in the pedestal region but also in the core across the L/I transition [White NF 2014]. The present CECE diagnostic system in C-Mod and these experimental results are described in this paper

  9. Edge Turbulence Imaging in the Alcator C-Mod Tokamak

    Energy Technology Data Exchange (ETDEWEB)

    S.J. Zweben; D.P. Stotler; J.L. Terry; B. LaBombard; M. Greenwald; M. Muterspaugh; C.S. Pitcher; the Alcator C-Mod Group; K. Hallatschek; R.J. Maqueda; B. Rogers; J.L. Lowrance; V.J. Mastrocola; G.F. Renda

    2001-11-26

    The 2-D radial vs. poloidal structure of edge turbulence in the Alcator C-Mod tokamak [I.H. Hutchinson, R. Boivin, P.T. Bonoli et al., Nuclear Fusion 41(2001) 1391] was measured using fast cameras and compared with 3-D numerical simulations of edge plasma turbulence. The main diagnostic is Gas Puff Imaging (GPI), in which the visible D(subscript alpha) emission from a localized D(subscript 2) gas puff is viewed along a local magnetic field line. The observed D(subscript alpha) fluctuations have a typical radial and poloidal scale of approximately 1 cm, and often have strong local maxima (''blobs'') in the scrape-off layer. The motion of this 2-D structure motion has also been measured using an ultra-fast framing camera with 12 frames taken at 250,000 frames/sec. Numerical simulations produce turbulent structures with roughly similar spatial and temporal scales and transport levels as that observed in the experiment; however, some differences are also noted, perhaps requiring diagnostic improvement and/or additional physics in the numerical model.

  10. High confinement dissipative divertor operation on Alcator C-Mod

    Energy Technology Data Exchange (ETDEWEB)

    Goetz, J.A.; LaBombard, B.; Lipschultz, B.; Pitcher, C.S.; Terry, J.L.; Boswell, C.; Gangadhara, S.; Pappas, D.; Weaver, J.; Welch, B.; Boivin, R.L.; Bonoli, P.; Fiore, C.; Granetz, R.; Greenwald, M.; Hubbard, A.; Hutchinson, I.; Irby, J.; Marmar, E.; Mossessian, D.; Porkolab, M.; Rice, J.; Rowan, W.L.; Schilling, G.; Snipes, J.; Takase, Y.; Wolfe, S.; Wukitch, S. [Plasma Science Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    1999-05-01

    Alcator C-Mod [I. H. Hutchinson {ital et al.}, Phys. Plasmas {bold 1}, 1511 (1994)] has operated a High-confinement-mode (H-mode) plasma together with a dissipative divertor and low core Z{sub eff}. The initially attached plasma is characterized by steady-state enhancement factor, H{sub ITER89P} [P. N. Yushmanov {ital et al.}, Nucl. Fusion {bold 30}, 1999 (1990)], of 1.9, central Z{sub eff} of 1.1, and a radiative fraction of {approximately}50{percent}. Feedback control of a nitrogen gas puff is used to increase radiative losses in both the core/edge and divertor plasmas in almost equal amounts. Simultaneously, the core plasma maintains H{sub ITER89P} of 1.6 and Z{sub eff} of 1.4 in this nearly 100{percent} radiative state. The power and particle flux to the divertor plates have been reduced to very low levels while the core plasma is relatively unchanged by the dissipative nature of the divertor. {copyright} {ital 1999 American Institute of Physics.}

  11. Scrape-off layer reflectometer for Alcator C-Moda)

    Science.gov (United States)

    Lau, Cornwall; Hanson, Greg; Wilgen, John; Lin, Yijun; Wukitch, Steve

    2010-10-01

    A swept-frequency X-mode reflectometer is being built for Alcator C-Mod to measure the scrape-off layer density profiles at the top, middle, and bottom locations in front of both the new lower hybrid launcher and the new ion cyclotron range of frequencies antenna. The system is planned to operate between 100 and 146 GHz at sweep rates from 10 μs to 1 ms, and will cover a density range of approximately 1016-1020 m-3 at B0=5-5.4 T. To minimize the effects of density fluctuations, both differential phase and full phase reflectometry will be employed. Design, test data, and calibration results of this electronics system will be discussed. To reduce attenuation losses, tallguide (TE01) will be used for most of the transmission line system. Simulations of high mode conversion in tallguide components, such as e-plane hyperbolic secant radius of curvature bends, tapers, and horn antennas will be shown. Experimental measurements of the total attenuation losses of these components in the lower hybrid waveguide run will also be presented.

  12. Implementation of LHCD Experiments on Alcator C-Mod

    Science.gov (United States)

    Parker, R.; Basse, N.; Beck, W.; Bernabei, S.; Childs, R.; Ellis, R.; Fredd, E.; Greenough, N.; Grimes, M.; Gwinn, D.; Hosea, J.; Irby, J.; Koert, P.; Kung, C. C.; Labombard, B.; Liptac, J.; Loesser, G. D.; Marmar, E.; Schilling, G.; Terry, D.; Terry, J.; Vieira, R.; Wallace, G.; Wilson, J. R.; Zaks, J.

    2005-09-01

    An antenna-transmitter system for driving current in the LHRF has been installed in Alcator C-Mod. The antenna is a grill consisting of 4 poloidal rows of waveguides, each with 24 guides in the toroidal direction. Power is supplied by 12 klystrons capable of 250 kW operation at a frequency of 4.6 GHz. Thus the total source power is 3 MW, with about 1.5 MW available to be coupled to the plasma. Power supply and heat throughput limits in C-Mod limit the pulse length to 5 s, which however represents several current redistribution times. With 90° phasing, the n∥ spectrum is sharply peaked at 2.3 and the range 1.5 < n∥ < 3.5 can be accessed dynamically by varying the phase of the klystrons. The system is in the commissioning phase with klystron power limited to ˜20 kW and pulse length to 10 ms. Early results from plasma operation are discussed.

  13. Non-axisymmetric Field Effects on Alcator C-Mod

    Science.gov (United States)

    Wolfe, S.; Hutchinson, I.; Granetz, R.; Rice, J.; Hubbard, A.; Irby, J.; Vieira, R.; Cochran, W.; Gwinn, D.; Rosati, J.; Lynn, A.

    2003-10-01

    A set of coils capable of producing non-axisymmetric, predominantly n=1, fields with different toroidal phase and a range of poloidal mode (m) spectra has been installed on Alcator C-Mod. This coilset has been used to suppress locked modes during low density or high current operation and also to induce locked modes in normally stable configurations in order to study error field effects. Locked modes are observed to result in braking of core toroidal rotation, modification of sawtooth activity, and significant reduction in energy and particle confinement. The inferred value of the threshold perturbation for producing a locked mode is of order B_21/B_T ˜ 10-4, where B_21 is the helically resonant m/n=2/1 field evaluated at the q=2 surface. This value is comparable to extrapolations based on experiments on JET and DIII-D, but is inconsistent with stronger BT and size scaling inferred from Compass-D results(R. J. Buttery, et al., 17th Fusion Energy Conference, Oct. 1998, Yokohama (IAEA-CN-69) EX8/5). The C-Mod result therefore has favorable implications for the locked mode threshold in ITER.

  14. Lower hybrid heating in the Alcator A tokamak

    Science.gov (United States)

    Schuss, J. J.; Porkolab, M.; Takase, Y.; Cope, D.; Fairfax, S.; Greenwald, M.; Gwinn, D.; Hutchinson, I. H.; Kusse, B.; Marmar, E.

    1981-04-01

    The results of the moderate-power (P less than 100 kW) Alcator A lower-hybrid-heating experiment are presented. In this experiment, RF power densities of up to 8 kW per sq cm were achieved for 40-ms pulses. Both electron and ion heating were observed as the plasma density was varied. No impurity influx or density rise was observed because of the RF pulse. The ion heating, however, as evidenced by the formation of an energetic ion tail in the plasma center, occurred at a lower plasma density than expected from linear plasma wave theory. Furthermore, the electron heating observed at lower densities was not expected from linear waveguide-plasma coupling theory. Contrary to expectations, the ion heating was found to be independent of the waveguide phasing. These results, together with RF probe measurements in the edge plasma, suggest that the lower hybrid waves launched by the array may undergo strong scattering from parametric instabilities or density fluctuations near the plasma edge.

  15. Alcator C-Mod ICRF antenna and matching circuit

    International Nuclear Information System (INIS)

    Alcator C-Mod will be a compact, high field, high density, divertor tokamak. Two FMIT transmitters will supply 4 MW of power in 1 sec pulses at 80 MHz for ICRF heating. Fast wave minority heating experiments are planned in D(3He) at 8 T and D(H) at 5.5 T. The first antenna will have a single current strap inside a box structure, which will be movable radially. The antenna will be inserted through a side port, making the rf power density on the antenna surface ∼2 kW/cm2 at 2 MW. The antenna will be center-tapped for mechanical strength and have a double layer Faraday screen tilted along the field lines. The antenna geometry was chosen to maximize power coupling assuming voltage-limited operation. A wide antenna with slotted box sides appears the best design, and 10 Ω of loading is required to couple 2 MW of power at a voltage limit of 40 kV. Matching is achieved by choice of the drive point to a resonant circuit formed by the antenna and a loop of transmission line outside of the vacuum and by tuning elements in the transmission line to the transmitter. 6 refs., 4 figs

  16. Correlation ECE diagnostic in Alcator C-Mod

    Directory of Open Access Journals (Sweden)

    Sung C.

    2015-01-01

    electron temperature, Te, fluctuations through standard cross-correlation analysis methods. In Alcator C-Mod, a new CECE diagnostic has been installed[Sung RSI 2012], and interesting phenomena have been observed in various plasma conditions. We find that local Te fluctuations near the edge (ρ ~ 0:8 decrease across the linearto- saturated ohmic confinement transition, with fluctuations decreasing with increasing plasma density[Sung NF 2013], which occurs simultaneously with rotation reversals[Rice NF 2011]. Te fluctuations are also reduced across core rotation reversals with an increase of plasma density in RF heated L-mode plasmas, which implies that the same physics related to the reduction of Te fluctuations may be applied to both ohmic and RF heated L-mode plasmas. In I-mode plasmas, we observe the reduction of core Te fluctuations, which indicates changes of turbulence occur not only in the pedestal region but also in the core across the L/I transition[White NF 2014]. The present CECE diagnostic system in C-Mod and these experimental results are described in this paper.

  17. Edge Turbulence Imaging in the Alcator C-Mod Tokamak

    International Nuclear Information System (INIS)

    The 2-D radial vs. poloidal structure of edge turbulence in the Alcator C-Mod tokamak [I.H. Hutchinson, R. Boivin, P.T. Bonoli et al., Nuclear Fusion 41(2001) 1391] was measured using fast cameras and compared with 3-D numerical simulations of edge plasma turbulence. The main diagnostic is Gas Puff Imaging (GPI), in which the visible D(subscript alpha) emission from a localized D(subscript 2) gas puff is viewed along a local magnetic field line. The observed D(subscript alpha) fluctuations have a typical radial and poloidal scale of approximately 1 cm, and often have strong local maxima (''blobs'') in the scrape-off layer. The motion of this 2-D structure motion has also been measured using an ultra-fast framing camera with 12 frames taken at 250,000 frames/sec. Numerical simulations produce turbulent structures with roughly similar spatial and temporal scales and transport levels as that observed in the experiment; however, some differences are also noted, perhaps requiring diagnostic improvement and/or additional physics in the numerical model

  18. Blob sizes and velocities in the Alcator C-Mod scrape-off layer

    DEFF Research Database (Denmark)

    Kube, R.; Garcia, O.E.; LaBombard, B.;

    A new blob-tracking algorithm for the GPI diagnostic installed in the outboard-midplane of Alcator C-Mod is developed. I t tracks large-amplitude fluctuations propagating through the scrape-off layer and calculates blob sizes and velocities. We compare the results of this method to a blob velocity...

  19. TSC [Tokamak Simulation Code] simulations of Alcator C-MOD discharges

    International Nuclear Information System (INIS)

    The axisymmetric stability of the single X-point, nominal Alcator C-MOD configuration is investigated with the Tokamak Simulation Code. The resistive wall passive growth rate, in the absence of feedback stabilization, is obtained. The instability is suppressed with an appropriate active feedback system. 2 refs., 25 figs., 1 tab

  20. Spectral measurements of fluctuating ω/sub pe/ radiation from Alcator C tokamak

    International Nuclear Information System (INIS)

    High resolution spectral measurements have been made of the fluctuating electron plasma frequency (ω/sub pe/) radiation from Alcator C. Three techniques have been used in making the measurements. Features as narrow as 350 kHz have been observed (Δf/f approx. = 6 x 10-6), impling that a highly coherent process is responsible for the emission

  1. Measurement of particle transport coefficients on Alcator C-Mod

    International Nuclear Information System (INIS)

    The goal of this thesis was to study the behavior of the plasma transport during the divertor detachment in order to explain the central electron density rise. The measurement of particle transport coefficients requires sophisticated diagnostic tools. A two color interferometer system was developed and installed on Alcator C-Mod to measure the electron density with high spatial (∼ 2 cm) and high temporal (≤ 1.0 ms) resolution. The system consists of 10 CO2 (10.6 μm) and 4 HeNe (.6328 μm) chords that are used to measure the line integrated density to within 0.08 CO2 degrees or 2.3 x 1016m-2 theoretically. Using the two color interferometer, a series of gas puffing experiments were conducted. The density was varied above and below the threshold density for detachment at a constant magnetic field and plasma current. Using a gas modulation technique, the particle diffusion, D, and the convective velocity, V, were determined. Profiles were inverted using a SVD inversion and the transport coefficients were extracted with a time regression analysis and a transport simulation analysis. Results from each analysis were in good agreement. Measured profiles of the coefficients increased with the radius and the values were consistent with measurements from other experiments. The values exceeded neoclassical predictions by a factor of 10. The profiles also exhibited an inverse dependence with plasma density. The scaling of both attached and detached plasmas agreed well with this inverse scaling. This result and the lack of change in the energy and impurity transport indicate that there was no change in the underlying transport processes after detachment

  2. Ion Bernstein wave experiments on the Alcator C tokamak

    International Nuclear Information System (INIS)

    Ion Bernstein wave experiments are carried out on the Alcator C tokamak to study wave excitation, propagation, absorption, and plasma heating due to wave power absorption. It is shown that ion Bernstein wave power is coupled into the plasma and follows the expected dispersion relation. The antenna loading is maximized when the hydrogen second harmonic layer is positioned just behind the antenna. Plasma heating results at three values of the toroidal magnetic field are presented. Central ion temperature increases of ΔT/sub i//Ti /approx lt/ 0.1 and density increases Δn/n 6s/sup /minus/1/ for plasmas within the density range 0.6 /times/ 1020m/sup /minus/3/ ≤ /bar n//sub e/ ≤ 4 /times/ 1020m/sup /minus/3/ and magnetic fields 2.4 ≥ ω/Ω/sub H/ ≥ 1.1. The density increases is usually accompanied by an improvement in the global particle confinement time relative to the Ohmic value. The ion heating rate is measured to be ΔT/sub i//P/sub rf/ ≅ 2-4.5 eV/kW at low densities. At higher densities /bar n//sub e/ ≤ 1.5 /times/ 1020m/sup /minus/3/ the ion heating rate dramatically decreases. It is shown that the decrease in the ion heating rate can be explained by the combined effects of wave scattering through the edge turbulence and the decreasing on energy confinement of these discharges with density. The effect of observed edge turbulence is shown to cause a broadening of the rf power deposition profile with increasing density. It is shown that the inferred value of the Ohmic ion thermal conduction, when compared to the Chang-Hinton neoclassical prediction, exhibits an increasing anomaly with increasing plasma density

  3. ICRF heating experiments on Alcator C-Mod

    Energy Technology Data Exchange (ETDEWEB)

    Takase, Y.; Bonoli, P.T.; Hubbard, A.; Mazurenko, A.; OShea, P.J.; Porkolab, M.; Reardon, J.; Wukitch, S.; Boivin, R. [MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139 (United States); Bombarda, F. [Associazione EURATOM-ENEA sulla Fusione, Frascati 00044 (Italy); Fiore, C.; Garnier, D.; Goetz, J.A.; Granetz, R.; Greenwald, M. [MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139 (United States); Hartmann, D. [Max-Planck-Institut fuer Plasmaphysik, D-85748 Garching (Germany); Hutchinson, I.H.; Irby, J.; LaBombard, B.; Lipschultz, B.; Marmar, E. [MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139 (United States); May, M. [Department of Physics, The John Hopkins University, Baltimore, Maryland 21218 (United States); Rice, J.; Rost, J.C.; Schachter, J.; Snipes, J.A.; Stek, P.; Terry, J. [MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139 (United States); Welch, B. [Institute for Plasma Research, University of Maryland, College Park, Maryland 20742 (United States); Wolfe, S. [MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139 (United States)

    1997-04-01

    Routine high power operation of the ICRF heating system (up to 3.5 MW at 80 MHz) has enabled studies of enhanced confinement modes as well as high heat flux divertor experiments in the Alcator C-Mod tokamak with toroidal magnetic fields of up to 8 T. H-mode was routinely observed when the edge temperature exceeded a threshold value. Boronization has reduced the radiated power to approximately 30{percent} of the input power, which had little effect on confinement of L-mode plasmas, but had a large impact on the performance of H-mode plasmas. It has become possible to achieve quasi-steady-state H-modes with H{approx_equal}2 and {beta}{sub N}{approx_equal}1.5 simultaneously with P{sub rad}/P{sub in}{approx_equal}0.3 and Z{sub eff}{approx_equal}1.5. PEP mode can be obtained with central ICRF heating combined with core fuelling by pellet injection. Because of the high central density, ion heating becomes the dominant heating channel during PEP mode. For direct electron heating schemes, such as heating by the mode converted ion Bernstein wave, the electron heating profile can be measured using the break-in-slope analysis of the electron temperature at rf power transitions. Mode conversion heating produced highly localized electron heating profiles, both on-axis and off-axis. Recent developments in full-wave codes have improved the agreement between the observed experimental results and the theoretically calculated power absorption profiles and power partition between ions and electrons. {copyright} {ital 1997 American Institute of Physics.}

  4. Overview of the Alcator C-Mod Research Program

    Science.gov (United States)

    Marmar, E.; Bader, A.; Bakhtiari, M.; Barnard, H.; Beck, W.; Bespamyatnov, I.; Binus, A.; Bonoli, P.; Bose, B.; Bitter, M.; Cziegler, I.; Dekow, G.; Dominguez, A.; Duval, B.; Edlund, E.; Ernst, D.; Ferrara, M.; Fiore, C.; Fredian, T.; Graf, A.; Granetz, R.; Greenwald, M.; Grulke, O.; Gwinn, D.; Harrison, S.; Harvey, R.; Hender, T. C.; Hosea, J.; Hill, K.; Howard, N.; Howell, D. F.; Hubbard, A.; Hughes, J. W.; Hutchinson, I.; Ince-Cushman, A.; Irby, J.; Izzo, V.; Kanojia, A.; Kessel, C.; Ko, J. S.; Koert, P.; La Bombard, B.; Lau, C.; Lin, L.; Lin, Y.; Lipschultz, B.; Liptac, J.; Ma, Y.; Marr, K.; May, M.; McDermott, R.; Meneghini, O.; Mikkelsen, D.; Ochoukov, R.; Parker, R.; Phillips, C. K.; Phillips, P.; Podpaly, Y.; Porkolab, M.; Reinke, M.; Rice, J.; Rowan, W.; Scott, S.; Schmidt, A.; Sears, J.; Shiraiwa, S.; Sips, A.; Smick, N.; Snipes, J.; Stillerman, J.; Takase, Y.; Terry, D.; Terry, J.; Tsujii, N.; Valeo, E.; Vieira, R.; Wallace, G.; Whyte, D.; Wilson, J. R.; Wolfe, S.; Wright, G.; Wright, J.; Wukitch, S.; Wurden, G.; Xu, P.; Zhurovich, K.; Zaks, J.; Zweben, S.

    2009-10-01

    This paper summarizes highlights of research results from the Alcator C-Mod tokamak covering the period 2006-2008. Active flow drive, using mode converted ion cyclotron waves, has been observed for the first time in a tokamak plasma, using a mix of D and 3He ion species; toroidal and poloidal flows are driven near the location of the mode conversion layer. ICRF induced edge sheaths are implicated in both the erosion of thin boron coatings and the generation of metallic impurities. Lower hybrid range of frequencies (LHRF) microwaves have been used for efficient current drive, current profile modification and toroidal flow drive. In addition, LHRF has been used to modify the H-mode pedestal, increasing temperature, decreasing density and lowering the pedestal collisionality. Studies of hydrogen isotope retention in solid metallic plasma facing components reveal significantly higher retention than expected from ex situ laboratory studies; a model to explain the results, based on plasma/neutral induced lattice damage, has been developed and tested. During gas-puff mitigation of disruptions, induced MHD instabilities cause the magnetic field to become stochastic, resulting in reduction of halo currents, spreading of plasma power loading and loss of runaway electrons before they cause damage. Detailed pedestal rotation profile measurements have been used to infer Er profiles, and correlation with global H-mode confinement. An improved L-mode regime, obtained at q95 <= 3 with ion drift away from the active X-point, shows very good energy confinement with a strong temperature pedestal, a weak density pedestal, and no evidence of particle or impurity accumulation, without the need for ELMs or any additional edge density regulation mechanism.

  5. Measurement of particle transport coefficients on Alcator C-Mod

    Energy Technology Data Exchange (ETDEWEB)

    Luke, T.C.T.

    1994-10-01

    The goal of this thesis was to study the behavior of the plasma transport during the divertor detachment in order to explain the central electron density rise. The measurement of particle transport coefficients requires sophisticated diagnostic tools. A two color interferometer system was developed and installed on Alcator C-Mod to measure the electron density with high spatial ({approx} 2 cm) and high temporal ({le} 1.0 ms) resolution. The system consists of 10 CO{sub 2} (10.6 {mu}m) and 4 HeNe (.6328 {mu}m) chords that are used to measure the line integrated density to within 0.08 CO{sub 2} degrees or 2.3 {times} 10{sup 16}m{sup {minus}2} theoretically. Using the two color interferometer, a series of gas puffing experiments were conducted. The density was varied above and below the threshold density for detachment at a constant magnetic field and plasma current. Using a gas modulation technique, the particle diffusion, D, and the convective velocity, V, were determined. Profiles were inverted using a SVD inversion and the transport coefficients were extracted with a time regression analysis and a transport simulation analysis. Results from each analysis were in good agreement. Measured profiles of the coefficients increased with the radius and the values were consistent with measurements from other experiments. The values exceeded neoclassical predictions by a factor of 10. The profiles also exhibited an inverse dependence with plasma density. The scaling of both attached and detached plasmas agreed well with this inverse scaling. This result and the lack of change in the energy and impurity transport indicate that there was no change in the underlying transport processes after detachment.

  6. Overview of the Alcator C-MOD research programme

    Science.gov (United States)

    Scott, S.; Bader, A.; Bakhtiari, M.; Basse, N.; Beck, W.; Biewer, T.; Bernabei, S.; Bonoli, P.; Bose, B.; Bravenec, R.; Bespamyatnov, I.; Childs, R.; Cziegler, I.; Doerner, R.; Edlund, E.; Ernst, D.; Fasoli, A.; Ferrara, M.; Fiore, C.; Fredian, T.; Graf, A.; Graves, T.; Granetz, R.; Greenough, N.; Greenwald, M.; Grimes, M.; Grulke, O.; Gwinn, D.; Harvey, R.; Harrison, S.; Hender, T. C.; Hosea, J.; Howell, D. F.; Hubbard, A. E.; Hughes, J. W.; Hutchinson, I.; Ince-Cushman, A.; Irby, J.; Jernigan, T.; Johnson, D.; Ko, J.; Koert, P.; La Bombard, B.; Kanojia, A.; Lin, L.; Lin, Y.; Lipschultz, B.; Liptac, J.; Lynn, A.; MacGibbon, P.; Marmar, E.; Marr, K.; May, M.; Mikkelsen, D. R.; McDermott, R.; Parisot, A.; Parker, R.; Phillips, C. K.; Phillips, P.; Porkolab, M.; Reinke, M.; Rice, J.; Rowan, W.; Sampsell, M.; Schilling, G.; Schmidt, A.; Smick, N.; Smirnov, A.; Snipes, J.; Stotler, D.; Stillerman, J.; Tang, V.; Terry, D.; Terry, J.; Ulrickson, M.; Vieira, R.; Wallace, G.; Whyte, D.; Wilson, J. R.; Wright, G.; Wright, J.; Wolfe, S.; Wukitch, S.; Wurden, G.; Yuh, H.; Zhurovich, K.; Zaks, J.; Zweben, S.

    2007-10-01

    Alcator C-MOD has compared plasma performance with plasma-facing components (PFCs) coated with boron to all-metal PFCs to assess projections of energy confinement from current experiments to next-generation burning tokamak plasmas. Low-Z coatings reduce metallic impurity influx and diminish radiative losses leading to higher H-mode pedestal pressure that improves global energy confinement through profile stiffness. RF sheath rectification along flux tubes that intersect the RF antenna is found to be a major cause of localized boron erosion and impurity generation. Initial lower hybrid current drive (LHCD) experiments (PLH < 900 kW) in preparation for future advanced-tokamak studies have demonstrated fully non-inductive current drive at Ip ~ 1.0 MA with good efficiency, Idrive = 0.4 PLH/neoR (MA, MW, 1020 m-3,m). The potential to mitigate disruptions in ITER through massive gas-jet impurity puffing has been extended to significantly higher plasma pressures and shorter disruption times. The fraction of total plasma energy radiated increases with the Z of the impurity gas, reaching 90% for krypton. A positive major-radius scaling of the error field threshold for locked modes (Bth/B ~ R0.68±0.19) is inferred from its measured variation with BT that implies a favourable threshold value for ITER. A phase contrast imaging diagnostic has been used to study the structure of Alfvén cascades and turbulent density fluctuations in plasmas with an internal transport barrier. Understanding the mechanisms responsible for regulating the H-mode pedestal height is also crucial for projecting performance in ITER. Modelling of H-mode edge fuelling indicates high self-screening to neutrals in the pedestal and scrape-off layer (SOL), and reproduces experimental density pedestal response to changes in neutral source, including a weak variation of pedestal height and constant width. Pressure gradients in the near SOL of Ohmic L-mode plasmas are observed to scale consistently as I_p^2

  7. D-D fusion neutron-spectra measurements and ion-temperature determination at Alcator C

    International Nuclear Information System (INIS)

    A neutron spectrometer system has been designed, assembled, and used to measure the D-D neutron spectrum at Alcator C. The design of the shielding and collimation was critical to the successful measurement of the spectrum and involved an integral approach in which the neutronics of the Alcator C was exploited to obtain a successful system. The system consists of a 3He ionization chamber mounted in a multi-component shield system. Essentially the outermost part of the shield and collimator has been designed to moderate the MeV-range neutrons to thermal energies. The inner part of the shield is designed to capture the thermalized neutrons with a minimum of gamma production. As a result, measurements during plasma discharges indicate that the ratio of the number of counts in the 2.45-MeV peak to the total number of neutron counts in the ion chamber is 1.67

  8. Status of the neutron diagnostic experiment for Alcator C-Mod

    Energy Technology Data Exchange (ETDEWEB)

    Fiore, C.L.; Boivin, R.; Granetz, R.S.; Fuller, T.; Kurz, C. (MIT Plasma Fusion Center, Cambridge, Massachusetts 02139 (United States))

    1992-10-01

    The Alcator C-Mod experiment is expected to produce neutrons at a rate of up to 1 {times} 10{sup 16} n/s during its highest performance operation. The global neutron detection system must provide accurate measurement of this production over the full operating regime of the experiment, 10{sup 11}--10{sup 16} n/s. This is accomplished using a series of uranium fission detectors enriched in U{sup 235} of staggered sensitivity. These are distributed in two moderator assemblies. A BF{sub 3} detector is added to each moderator to cover the lowest operational range. Preliminary calibration of the system has been accomplished using a 65.4 {mu}g Cf{sup 252} source placed inside the Alcator C-Mod vacuum vessel. The system design and calibration is discussed herein.

  9. Direct detection of lower hybrid wave using a reflectometer on Alcator C-Moda)

    Science.gov (United States)

    Shiraiwa, S.; Baek, S.; Dominguez, A.; Marmar, E.; Parker, R.; Kramer, G. J.

    2010-10-01

    The possibility of directly detecting a density perturbation produced by lower hybrid (LH) waves using a reflectometer is presented. We investigate the microwave scattering of reflectometer probe beams by a model density fluctuation produced by short wavelength LH waves in an Alcator C-Mod experimental condition. In the O-mode case, the maximum response of phase measurement is found to occur when the density perturbation is approximately centimeters in front of the antenna, where Bragg scattering condition is satisfied. In the X-mode case, the phase measurement is predicted to be more sensitive to the density fluctuation close to the cut-off layer. A feasibility test was carried out using a 50 GHz O-mode reflectometer on the Alcator C-Mod tokamak, and positive results including the detection of 4.6 GHz pump wave and parametric decay instabilities were obtained.

  10. Observation of Lower-Hybrid Current Drive at High Densities in the Alcator C Tokamak

    Science.gov (United States)

    Porkolab, M.; Schuss, J. J.; Lloyd, B.; Takase, Y.; Texter, S.; Bonoli, P.; Fiore, C.; Gandy, R.; Gwinn, D.; Lipschultz, B.; Marmar, E.; Pappas, D.; Parker, R.; Pribyl, P.

    1984-07-01

    A quasi-steady-state lower-hybrid current-drive operation is demonstrated in the Alcator C tokamak at densities up to n―e~=1×1014 cm-3. The current-drive efficiency is measured experimentally over a wide range of densities and magnetic fields. The radial distribution of high-energy x rays indicates that the current-carrying electrons peak near the plasma axis.

  11. Energy Confinement of High-Density Pellet-Fueled Plasmas in the Alcator C Tokamak

    Science.gov (United States)

    Greenwald, M.; Gwinn, D.; Milora, S.; Parker, J.; Parker, R.; Wolfe, S.; Besen, M.; Camacho, F.; Fairfax, S.; Fiore, C.; Foord, M.; Gandy, R.; Gomez, C.; Granetz, R.; Labombard, B.; Lipschultz, B.; Lloyd, B.; Marmar, E.; McCool, S.; Pappas, D.; Petrasso, R.; Pribyl, P.; Rice, J.; Schuresko, D.; Takase, Y.; Terry, J.; Watterson, R.

    1984-07-01

    A series of pellet-fueling experiments has been carried out on the Alcator C tokamak. High-speed hydrogen pellets penetrate to within a few centimeters of the magnetic axis, raise the plasma density, and produce peaked density profiles. Energy confinement is observed to increase over similar discharges fueled only by gas puffing. In this manner record values of electron density, plasma pressure, and Lawson number (n τ) have been achieved.

  12. Pedestal structure and stability in H-mode and I-mode: a comparative study on Alcator C-Mod

    International Nuclear Information System (INIS)

    New experimental data from the Alcator C-Mod tokamak are used to benchmark predictive modelling of the edge pedestal in various high-confinement regimes, contributing to greater confidence in projection of pedestal height and width in ITER and reactors. ELMy H-modes operate near stability limits for ideal peeling–ballooning modes, as shown by calculations with the ELITE code. Experimental pedestal width in ELMy H-mode scales as the square root of βpol at the pedestal top, i.e. the dependence expected from theory if kinetic ballooning modes (KBMs) were responsible for limiting the pedestal width. A search for KBMs in experiment has revealed a short-wavelength electromagnetic fluctuation in the pedestal that is a candidate driver for inter-edge localized mode (ELM) pedestal regulation. A predictive pedestal model (EPED) has been tested on an extended set of ELMy H-modes from C-Mod, reproducing pedestal height and width reasonably well across the data set, and extending the tested range of EPED to the highest absolute pressures available on any existing tokamak and to within a factor of three of the pedestal pressure targeted for ITER. In addition, C-Mod offers access to two regimes, enhanced D-alpha (EDA) H-mode and I-mode, that have high pedestals, but in which large ELM activity is naturally suppressed and, instead, particle and impurity transport are regulated continuously. Pedestals of EDA H-mode and I-mode discharges are found to be ideal magnetohydrodynamic (MHD) stable with ELITE, consistent with the general absence of ELM activity. Invocation of alternative physics mechanisms may be required to make EPED-like predictions of pedestals in these kinds of intrinsically ELM-suppressed regimes, which would be very beneficial to operation in burning plasma devices. (paper)

  13. D-D neutron energy-spectra measurements in Alcator C

    International Nuclear Information System (INIS)

    Measurements of energy spectra of neutrons produced during high density (anti n/sub e/ > 2 x 1014 cm-3) deuterium discharges have been performed using a proton-recoil (NE 213) spectrometer. A two foot section of light pipe (coupling the scintillator and photomultiplier) was used to extend the scintillator into a diagnostic viewing port to maximize the neutron detection efficiency while not imposing excessive magnetic shielding requirements. A derivative unfolding technique was used to deduce the energy spectra. The results showed a well defined peak at 2.5 MeV which was consistent with earlier neutron flux measurements on Alcator C that indicated the neutrons were of thermonuclear origin

  14. 20 years of research on the Alcator C-Mod tokamak

    OpenAIRE

    Greenwald, Martin; Bader, A; Baek, S.; M. Bakhtiari; Barnard, H.; Beck, W.; Bergerson, W; Bespamyatnov, I; Bonoli, P.; Brower, D; Brunner, D.; Burke, W.; Candy, J.; Churchill, M; Cziegler, I.

    2014-01-01

    The object of this review is to summarize the achievements of research on the Alcator C-Mod tokamak [Hutchinson et al., Phys. Plasmas 1, 1511 (1994) and Marmar, Fusion Sci. Technol. 51, 261 (2007)] and to place that research in the context of the quest for practical fusion energy. C-Mod is a compact, high-field tokamak, whose unique design and operating parameters have produced a wealth of new and important results since it began operation in 1993, contributing data that extends tests of crit...

  15. Preparing the Alcator C bolometer system for use on MTX (Microwave Tokamak Experiment)

    Science.gov (United States)

    Marinak, Marty

    1988-02-01

    The Alcator C bolometer array has been modified to be compatible with electron cyclotron heating on the Microwave Tokamak Experiment. Fine wire mesh screens are mounted on the front of the bolometer collimator tubes to attenuate microwave heating of the bolometers. Structural changes eliminate openings in the seams of the bolometer housing, which represent pathways for microwaves to enter the system. This paper outlines the operational principles of the bolometer system, discusses the measured and predicted performance characteristics of the bolometer array, and includes a concise guide to the operation of the bolometer controller.

  16. Superconducting qualification program for TFCX and alcator DCT magnetic systems

    International Nuclear Information System (INIS)

    The purpose of the Magnetics Qualification Program is to demonstrate the feasibility of ICCS conductors for TF and PF coils for TFCX and DCT. Conductor requirements for these projects represent an advance over LCP conductors in peak field, overall current density, and in strand-to-strand decoupling. Achievement of these advanced parameters results in significant device performance improvement and cost savings over the performance achievable with the LCP ICCS Westinghouse/Airco Conductor

  17. Experimental study of visible and ultraviolet impurity emission from the Alcator C tokamak

    International Nuclear Information System (INIS)

    Densities of carbon, oxygen, and silicon in Alcator C tokamak plasmas have been computed from spectroscopic measurements of the absolute brightnesses of visible and ultraviolet emission lines in combination with a one dimensional numerical calculation which models the charge state and emissivity profiles. Profiles of all the charge states of a particular impurity were calculated by utilizing independent measurements of plasma density and temperature and solving the coupled system of transport and rate equations connecting the ionization states. These profiles were then used to calculate emissivity and brightness profiles by solving the matrix equation relating the level populations through atomic processes such as electron impact excitation, de-excitation, spontaneous emission and cascades from upper levels. Good agreement was found between predicted impurity line brightnesses and experimentally measured brightnesses of different charge states. Three different types of limiter materials, molybdenum, graphite and SiC coated graphite have been used on Alcator C. It was determined that the principal impurities in the plasma, under most conditions, depends upon the type of limiter being used. However, the sources of the impurities are both the wall and the limiters, since it was observed that the wall becomes coated with limiter material due to plasma discharges

  18. Pioneering Structural Solutions for Compact High Field Experiments Developed for the Alcator and the Ignitor Programs

    Science.gov (United States)

    Salvetti, M.; Coppi, B.

    2015-11-01

    Recently there has been an increased awareness of the fact that the line of research based on compact high field machines is the most promising to approach ignition conditions in DT burning plasmas and has acquired new perspectives for its applications. Then the technological solutions that have made these machines possible have become subject to new attention and, in some cases, to rediscovery. The Alcator Program and, followed by Ignitor Program, has led to invent the coupled air-core former poloidal field system that has made compact machine possible and has been adopted on all advanced toroidal machines that came after Alcator. A recently rediscovered solution aimed at reducing the mechanical stresses in the inner legs of the toroidal magnet coils is the ``Upper and Lower Bracing Rings'' system that has had a key role in the design of the Ignitor machine and its evolution. Another solution to minimize the machine dimensions while maintaining high toroidal fields, in order to achieve high plasma current densities, is that of ``bucking and wedging'' of the toroidal magnet by coupling it mechanically to the central solenoid. Sponsored in part by the U.S. DoE.

  19. RF heating and current drive experiments on the Alcator C and Versator II tokamaks

    International Nuclear Information System (INIS)

    Lower hybrid heating and current drive experiments on the Alcator C tokamak (R = 0.64 m, a = 0.165 m, molybdenum limiters) were performed at a frequency of 4.6 GHz with net injected rf powers up to P/sub rf/ ≤ 1.5 MW. Recent experiments have focused on energy confinement studies in lower hybrid current-driven (LHCD) and LHRF heated Ohmic discharges, and sawtooth stabilization in combined LHCD-OH driven discharges at densities n-bar/sub e/ ≤ 1.4 x 1020 m-3. Ion Bernstein wave heating experiments were also carried out in Alcator C at a frequency of f = 183 MHz at power levels P/sub rf/ ≤ 200 kW. Significant heating (ΔT/sub i/ ≤ 400 eV) was observed at ω/ω/sub CH/ ≅ 1.5, 2.5 and ω/ω/sub CD/ ≅ 2.5 at densities n-bar/sub e/ ≅ 1 x 1020 m-3. In the Versator II tokamak, particle confinement improvement (by factors of ≅2) was observed in the presence of 2.45 GHz lower hybrid current drive

  20. Poloidal asymmetries in the limiter shadow plasma of the Alcator C tokamak. Volume 1

    International Nuclear Information System (INIS)

    This thesis investigates conditions which exist in the limiter shadow plasma of the Alcator C tokamak. The understanding of this edge plasma region is approached from both experimental and theoretical points of view. First, a general overview of edge plasma physical processes is presented. Simple edge plasma models and conditions which can theoretically result in a poloidally asymmetric edge plasma are discussed. A review of data obtained from previous diagnostics in the Alcator C edge plasma is then used to motivate the development of a new edge plasma diagnostic system (DENSEPACK) to experimentally investigate poloidal asymmetries in this region. The bulk of this thesis focuses on the marked poloidal asymmetries detected by this poloidal probe array and possible mechanisms which might support such asymmetries on a magnetic flux surface. In processing the probe data, some important considerations on fitting Langmuir probe characteristics are identified. The remainder of this thesis catalogues edge versus central plasma parameter dependences. Regression analysis techniques are applied to characterize edge density for various central plasma parameters. Edge plasma conditions during lower hybrid radio frequency heating and pellet injection are also discussed

  1. RF heating and current drive experiments on the Alcator C and Versator II tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Porkolab, M.; Bonoli, P.; Chen, K.I.; Fiore, C.; Granetz, R.; Griffin, D.; Gwinn, D.; Knowlton, S.; Lipschultz, B.; Luckhardt, S.C.

    1986-11-01

    Lower hybrid heating and current drive experiments on the Alcator C tokamak (R = 0.64 m, a = 0.165 m, molybdenum limiters) were performed at a frequency of 4.6 GHz with net injected rf powers up to P/sub rf/ less than or equal to 1.5 MW. Recent experiments have focused on energy confinement studies in lower hybrid current-driven (LHCD) and LHRF heated Ohmic discharges, and sawtooth stabilization in combined LHCD-OH driven discharges at densities n-bar/sub e/ less than or equal to 1.4 x 10/sup 20/ m/sup -3/. Ion Bernstein wave heating experiments were also carried out in Alcator C at a frequency of f = 183 MHz at power levels P/sub rf/ less than or equal to 200 kW. Significant heating (..delta..T/sub i/ less than or equal to 400 eV) was observed at ..omega../..omega../sub CH/ approx. = 1.5, 2.5 and ..omega../..omega../sub CD/ approx. = 2.5 at densities n-bar/sub e/ approx. = 1 x 10/sup 20/ m/sup -3/. In the Versator II tokamak, particle confinement improvement (by factors of approx. =2) was observed in the presence of 2.45 GHz lower hybrid current drive.

  2. Novel energy resolving x-ray pinhole camera on Alcator C-Mod

    Energy Technology Data Exchange (ETDEWEB)

    Pablant, N. A.; Delgado-Aparicio, L.; Bitter, M.; Ellis, R.; Hill, K. W. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States); Brandstetter, S.; Eikenberry, E.; Hofer, P.; Schneebeli, M. [Dectris Ltd., Baden (Switzerland)

    2012-10-15

    A new energy resolving x-ray pinhole camera has been recently installed on Alcator C-Mod. This diagnostic is capable of 1D or 2D imaging with a spatial resolution of Almost-Equal-To 1 cm, an energy resolution of Almost-Equal-To 1 keV in the range of 3.5-15 keV and a maximum time resolution of 5 ms. A novel use of a Pilatus 2 hybrid-pixel x-ray detector [P. Kraft et al., J. Synchrotron Rad. 16, 368 (2009)] is employed in which the lower energy threshold of individual pixels is adjusted, allowing regions of a single detector to be sensitive to different x-ray energy ranges. Development of this new detector calibration technique was done as a collaboration between PPPL and Dectris Ltd. The calibration procedure is described, and the energy resolution of the detector is characterized. Initial data from this installation on Alcator C-Mod is presented. This diagnostic provides line-integrated measurements of impurity emission which can be used to determine impurity concentrations as well as the electron energy distribution.

  3. Design of a New Optical System for Alcator C-Mod Motional Stark Effect Diagnostic

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Jinseok; Scott, Steve; Manfred, Bitter; Lerner, Lerner

    2009-11-12

    The motional Stark effect (MSE) diagnostic on Alcator C-Mod uses an in-vessel optical system (five lenses and three mirrors) to relay polarized light to an external polarimeter because port access limitations on Alcator C-Mod preclude a direct view of the diagnostic beam. The system experiences unacceptable, spurious drifts of order several degrees in measured pitch angle over the course of a run day. Recent experiments illuminated the MSE diagnostic with polarized light of fixed orientation as heat was applied to various optical elements. A large change in measured angle was observed as two particular lenses were heated, indicating that thermal-stress-induced birefringence is a likely cause of the spurious variability. Several new optical designs have been evaluated to eliminate the affected in-vessel lenses and to replace the focusing they provide with curved mirrors; however, ray tracing calculations imply that this method is not feasible. A new approach is under consideration that utilizes in situ calibrations with in-vessel reference polarized light sources. 2008 American Institute of Physics.

  4. ICRF antenna matching system with ferrite tuners for the Alcator C-Mod tokamak

    Science.gov (United States)

    Lin, Y.; Binus, A.; Wukitch, S. J.; Koert, P.; Murray, R.; Pfeiffer, A.

    2015-12-01

    Real-time fast ferrite tuning (FFT) has been successfully implemented on the ICRF antennas on Alcator C-Mod. The former prototypical FFT system on the E-port 2-strap antenna has been upgraded using new ferrite tuners that have been designed specifically for the operational parameters of the Alcator C-Mod ICRF system (˜ 80 MHz). Another similar FFT system, with two ferrite tuners and one fixed-length stub, has been installed on the transmission line of the D-port 2-strap antenna. These two systems share a Linux-server-based real-time controller. These FFT systems are able to achieve and maintain the reflected power to the transmitters to less than 1% in real time during the plasma discharges under almost all plasma conditions, and help ensure reliable high power operation of the antennas. The innovative field-aligned (FA) 4-strap antenna on J-port has been found to have an interesting feature of loading insensitivity vs. plasma conditions. This feature allows us to significantly improve the matching for the FA J-port antenna by installing carefully designed stubs on the two transmission lines. The reduction of the RF voltages in the transmission lines has enabled the FA J-port antenna to deliver 3.7 MW RF power to plasmas out of the 4 MW source power in high performance I-mode plasmas.

  5. Production of internal transport barriers via self-generated mean flows in Alcator C-Moda)

    Science.gov (United States)

    Fiore, C. L.; Ernst, D. R.; Podpaly, Y. A.; Mikkelsen, D.; Howard, N. T.; Lee, Jungpyo; Reinke, M. L.; Rice, J. E.; Hughes, J. W.; Ma, Y.; Rowan, W. L.; Bespamyatnov, I.

    2012-05-01

    New results suggest that changes observed in the intrinsic toroidal rotation influence the internal transport barrier (ITB) formation in the Alcator C-Mod tokamak [E. S. Marmar and Alcator C-Mod group, Fusion Sci. Technol. 51, 261 (2007)]. These arise when the resonance for ion cyclotron range of frequencies (ICRF) minority heating is positioned off-axis at or outside of the plasma half-radius. These ITBs form in a reactor relevant regime, without particle or momentum injection, with Ti ≈ Te, and with monotonic q profiles (qmin 1.5 × 105 rad/s) in the region where the ITB foot is observed. Gyrokinetic analyses indicate that this spontaneous shearing rate is comparable to the linear ion temperature gradient (ITG) growth rate at the ITB location and is sufficient to reduce the turbulent particle and energy transport. New and detailed measurement of the ion temperature demonstrates that the radial profile flattens as the ICRF resonance position moves off axis, decreasing the drive for the ITG the instability as well. These results are the first evidence that intrinsic rotation can affect confinement in ITB plasmas.

  6. Novel energy resolving x-ray pinhole camera on Alcator C-Moda)

    Science.gov (United States)

    Pablant, N. A.; Delgado-Aparicio, L.; Bitter, M.; Brandstetter, S.; Eikenberry, E.; Ellis, R.; Hill, K. W.; Hofer, P.; Schneebeli, M.

    2012-10-01

    A new energy resolving x-ray pinhole camera has been recently installed on Alcator C-Mod. This diagnostic is capable of 1D or 2D imaging with a spatial resolution of ≈1 cm, an energy resolution of ≈1 keV in the range of 3.5-15 keV and a maximum time resolution of 5 ms. A novel use of a Pilatus 2 hybrid-pixel x-ray detector [P. Kraft et al., J. Synchrotron Rad. 16, 368 (2009), 10.1107/S0909049509009911] is employed in which the lower energy threshold of individual pixels is adjusted, allowing regions of a single detector to be sensitive to different x-ray energy ranges. Development of this new detector calibration technique was done as a collaboration between PPPL and Dectris Ltd. The calibration procedure is described, and the energy resolution of the detector is characterized. Initial data from this installation on Alcator C-Mod is presented. This diagnostic provides line-integrated measurements of impurity emission which can be used to determine impurity concentrations as well as the electron energy distribution.

  7. Lower-hybrid-heating experiments on the Alcator C and the Versator II Tokamaks

    Science.gov (United States)

    Porkolab, M.; Schuss, J. J.; Takase, Y.; Texter, S.; Fiore, C. L.; Gandy, R.; Greenwald, M. J.; Gwinn, D. A.; Lipschultz, B.; Marmar, E. S.

    Initial results from lower hybrid wave heating experiments carried out on the MIT Alcator-C and Versator II Tokamak are reported. In the Alcator-C experiments a 4 waveguide array, with internally brazed ceramic windows was used to inject 160 kW of microwave power at 4.6 GHz into the plasma with nO less than or equal to 1 x 10(15) cm(+3), and BO less than or equal to 12 T. The RF coupling studies show optimal coupling when the local density at the waveguide mouth is 25 to 50 times overdense. Heating experiments show an ion tail formation in hydrogen discharge peaking at a density of anti-n approx. = 2.7 x 10(14) cm(+3) at B = 8.9 T, and bulk ion heating at a density of anti n approx. = 1.5 x 10(14) c(+3) at B approx. = 11 T. Evidence of RF current enhancement has been observed at a density of n approx. = 3 x 10(13) cm (+3). Doppler broadening of the OVII and NVI lines shows a (RADICAL)T/sub i/= 50 eV rise in the bulk ion temperature. A significant RF produced ion tail is also observed by charge exchange analysis. A toroidal ray tracing code and a 1-D transport code to study the heating density bands and heating efficiencies were successfully combined.

  8. Second Harmonics of Reversed Shear TAE in Alcator C-Mod Geometry

    Science.gov (United States)

    Chen, Eugene; Berk, Herbert; Breizman, Boris; Zheng, Linjin

    2009-11-01

    Experiments on Alcator C-Mod, operating with reversed magnetic shear, reveal Toroidal Alfven Eigenmodes (TAE) together with signals at twice the mode frequency. The double frequency signals can be viewed as second harmonic sidebands driven by quadratic non-linear terms in the MHD equations, in analogy with a corresponding theory for Alfven Cascades [1]. However, these nonlinear sidebands have not yet been quantified by any of the existing codes. In this work, we extend AEGIS code [2] to capture nonlinear effects iteratively by treating the nonlinear terms as a driving source in the linear MHD solver. We first compute the TAE mode structure for realistic geometry and q-profile and then use it to find the spatial structure of the second harmonic density perturbation, which can be directly compared with PCI measurements at Alcator C-Mod. [1] H. Smith, B. N. Breizman, M. Lisak and D. Anderson, Physics of Plasmas 13 042504 (2006) [2] L. J. Zheng and M. Kotschenreuther, Journal of Computational Physics 211 (2006) 748-766

  9. Study of the Effects of Neutrals in Alcator C-Mod Plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Boivin, R L; Boswell, C; Goetz, J A; Hubbard, A E; Irby, J; LaBombard, B; Marmar, E S; Mossessian, D; Owen, L W; Pitcher, C S; Terry, J L

    1999-06-14

    Recently, much effort has been dedicated to understanding the bifurcation involved in the transition from a low to high confinement regime. While several theories have been brought forward, many factors remain to be elucidated, one of which involves the role played by neutral particles in the evolution of a transport barrier near the edge of the plasma. Alcator C-Mod is especially well suited for the study of neutral particle effects, mainly because of its high plasma and neutral densities, and closed divertor geometry. Alcator C-Mod employs ICRF as auxiiiary heating for obtaining a high confinement regime, although ohmic H-modes are routinely obtained as well. The neutrals can enter the edge dynamics through the particle, momentum and energy balance. In the particle balance, the source of neutrals has to be evaluated vis-8-vis the formation of the edge density pedestal. It is widely believed that plasma rotation is an important factor in reducing transport. In this case, neutrals could act as a momentum sink, through the charge-exchange process. That same process can also modify the energy balance of the plasma near the edge by increasing the cross-field heat flux. These effects are quite difficult to measure experimentally, in large part because neutral particle diagnosis is not an easy task, and because of the inherent 3-dimensional aspect of the problem. Consequently, the neutral's spatial and energy distributions are usually not well known. In Alcator C-Mod, we recently implemented a series of diagnostics for the purpose of measuring these distributions. They include measurements of the neutral pressure at many locations around the tokamak, and spatially resolved measurements of Lyman-a and charge-exchange power emission. A high-resolution multichord (20 channels) tangential view of neutral deuterium emission (Lyman-a) has been recently installed near the midplane. The viewing area covers approximately 4 cm across the separatrix, with a nominal 2 mm

  10. Neutral particle analysis of ICRF heated discharges on Alcator C-Mod

    Energy Technology Data Exchange (ETDEWEB)

    Lee, W D; Boivin, R L; Bonoli, P T; Fiore, C L; Hubbard, A; Irby, J; Nelson-Melby, E; Porkolab, M; Wukitch, S J [NW17-121 MIT-PSFC Massachusetts Institute of Technology, 175 Albany Street, Cambridge, MA 02139 (United States)

    2003-08-01

    A neutral particle analyser (NPA) has been used to make measurements of the ion distribution in the Alcator C-Mod tokamak. We have used the analyser to measure the energy distribution of majority deuterons and minority hydrogen (up to 20 keV) at 0.4{<=}r/a{<=}0.6, during minority ion cyclotron range of frequencies (ICRF) heating. These energy spectra were also simulated by using the predicted minority ion distribution from a combined Fokker Planck ICRF code in a model for the neutral particle flux. The model predictions for neutral flux were found to be in qualitative agreement with the measured energy spectra. The energy spectra for two different ICRF antenna configurations were also measured and found to be very similar.

  11. High resolution measurements of neutral density and ionization rate in the Alcator C-Mod tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Boivin, R. L.; Hughes, J. W.; LaBombard, B.; Mossessian, D.; Terry, J. L.

    2001-01-01

    Two new high resolution detectors have been installed on the Alcator C-Mod tokamak to measure the neutral density and ionization rate at the edge of the main chamber plasma. Using a silicon detector sensitive to UV light, and a very narrow filter with transmission peaking at 1216 Aa, the Lyman alpha radiation emanating from neutral deuterium (and hydrogen) is measured. The detectors consist of 20 channel arrays which view the plasma tangentially 12.5 cm below the outer midplane, and 10 cm above the inner midplane. The imaging is performed using a 1mmx3mm slit, which gives a nominal radial resolution of 2 and 3 mm, respectively. The local emissivity is obtained via a standard Abel inversion technique. Employing well-known branching ratios, and using measured local electron density and temperature, the neutral density and ionization rate are inferred with similar radial resolution. Details of the setup and sensitivity of the results to plasma conditions are discussed.

  12. Design of a correlation electron cyclotron emission diagnostic for Alcator C-Moda)

    Science.gov (United States)

    Sung, C.; White, A. E.; Irby, J. H.; Leccacorvi, R.; Vieira, R.; Oi, C. Y.; Peebles, W. A.; Nguyen, X.

    2012-10-01

    A correlation electron cyclotron emission (CECE) diagnostic has been installed in Alcator C-Mod. In order to measure electron temperature fluctuations, this diagnostic uses a spectral decorrelation technique. Constraints obtained with nonlinear gyrokinetic simulations guided the design of the optical system and receiver. The CECE diagnostic is designed to measure temperature fluctuations which have kθ ≤ 4.8 cm-1 (kθρs < 0.5) using a well-focused beam pattern. Because the CECE diagnostic is a dedicated turbulence diagnostic, the optical system is also flexible, which allows for various collimating lenses and antenna to be used. The system overview and the demonstration of its operability as designed are presented in this paper.

  13. First results of the SOL reflectometer on Alcator C-Moda)

    Science.gov (United States)

    Lau, C.; Hanson, G.; Lin, Y.; Wilgen, J.; Wukitch, S.; Labombard, B.; Wallace, G.

    2012-10-01

    A swept-frequency X-mode reflectometer has been built on Alcator C-Mod to measure the scrape-off layer (SOL) density profiles adjacent to the lower hybrid launcher. The reflectometer system operates between 100 and 146 GHz at sweep rates from 10 μs to 1 ms and covers a density range of ˜1016-1020 m-3 at B0 = 5-5.4 T. This paper discusses the analysis of reflectometer density profiles and presents first experimental results of SOL density profile modifications due to the application of lower hybrid range-of-frequencies power to L-mode discharges. Comparison between density profiles measured by the X-mode reflectometer and scanning Langmuir probes is also shown.

  14. Divertor heat flux footprints in EDA H-mode discharges on Alcator C-Mod

    International Nuclear Information System (INIS)

    The physics that sets the width of the power exhaust channel in a tokamak scrape-off layer and its scaling with engineering parameters is of fundamental importance for reactor design, yet it remains to be understood. An extensive array of divertor heat flux diagnostics was recently commissioned in Alcator C-Mod with the aim of improving our understanding. Initial results are reported from EDA H-mode discharges in which plasma current, input power, toroidal field and magnetic topology were varied. The integral width of the outer divertor heat flux footprint is found to lie in the range of 3-5 mm mapped to the mid-plane. Widths are insensitive to single versus double-null topology and the magnitude of toroidal field. Pedestal physics appears to largely determine these widths; a dependence of width on plasma thermal energy is noted, yielding a reduction in width as plasma current is increased for the best EDA H-modes.

  15. ECE Temperature Fluctuations associated with EDA H-Mode discharges in Alcator C-Mod

    Science.gov (United States)

    Phillips, P. E.; Lynn, A. G.

    2006-10-01

    Alcator C-Mod exhibits an ELM-free H-mode with ``enhanced,,lpha'' emission accompanied by a quasi-coherent mode (QCM) edge relaxation mechanism. This steady state H-mode lowers the peak heat load to the diverters which is advantageous for reactor operations. A high-resolution heterodyne electron-cyclotron-emission (ECE) radiometer with 32 channels (δR˜7mm) and a bandwidth up to 1MHz covering the full radius of C-Mod has observed spatial resolved temperature fluctuations that are highly correlated with the edge QCM mode. The QCM mode is also directly observed by the edge ECE channels though the changes in optical depth due to the large density fluctuations in the QCM (˜30%). Details of these measurements will be presented in this poster.

  16. Divertor heat flux footprints in EDA H-mode discharges on Alcator C-Mod

    Energy Technology Data Exchange (ETDEWEB)

    LaBombard, B., E-mail: labombard@psfc.mit.edu [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Terry, J.L.; Hughes, J.W.; Brunner, D.; Payne, J.; Reinke, M.L.; Lin, Y.; Wukitch, S. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

    2011-08-01

    The physics that sets the width of the power exhaust channel in a tokamak scrape-off layer and its scaling with engineering parameters is of fundamental importance for reactor design, yet it remains to be understood. An extensive array of divertor heat flux diagnostics was recently commissioned in Alcator C-Mod with the aim of improving our understanding. Initial results are reported from EDA H-mode discharges in which plasma current, input power, toroidal field and magnetic topology were varied. The integral width of the outer divertor heat flux footprint is found to lie in the range of 3-5 mm mapped to the mid-plane. Widths are insensitive to single versus double-null topology and the magnitude of toroidal field. Pedestal physics appears to largely determine these widths; a dependence of width on plasma thermal energy is noted, yielding a reduction in width as plasma current is increased for the best EDA H-modes.

  17. Initial ICRF coupling and heating experiments on Alcator C-Mod

    International Nuclear Information System (INIS)

    Initial ICRF coupling studies were performed successfully on the Alcator C-Mod tokamak with all-metallic first wall, using a radially movable single-current-strap (monopole) antenna. The plasma loading is 10-40 times the vacuum loading, which is sufficient to inject 2MW of r.f. power through one two-strap (dipole) antenna. The observed loading is consistent with predictions of full-wave calculations. Up to 1MW of r.f. power (antenna power density of XXXX10MWm-2) has been injected into the C-Mod plasma without serious impurity problems. Definite signs of both ion and electron heating were observed at power levels of 0.4MW and higher (PRF/POHXXXX0.3) in the D(H) minority heating regime. High-power heating experiments with 4MW of source power and two dipole antennas began in May 1994. ((orig.))

  18. High resolution bolometry on the Alcator C-Mod tokamak (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Boivin, R.L.; Goetz, J.A.; Marmar, E.S.; Rice, J.E.; Terry, J.L. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, 175 Albany Street, Cambridge, Massachusetts 02139 (United States)

    1999-01-01

    Recent breakthroughs in silicon detector technology now permit measurement of radiated power over a wide range in photon energies. These detectors (also known as AXUV photodiodes) have a flat spectral power response from ultraviolet to x-ray energies, and with a slightly reduced efficiency all the way down to visible wavelengths. Since they can be made small, multichannel detectors allow high spatial resolution to be combined with an intrinsic high temporal resolution, which can reach the microsecond range, depending on the application. Additional features include ease of use and installation, and relatively low cost compared to other techniques. A combination of two multichannel toroidally viewing systems has been recently installed on the Alcator C-Mod tokamak. The first array, which is composed of 16 channels, sees tangentially the outer-half of the plasma at the midplane, and is used to measure the total power radiated. The second array, also located at the midplane, consists of 19 channels and views the edge of the plasma. This array has a 2 mm radial resolution, allowing, for example, the study of edge dynamics in high confinement (H mode) plasmas. Because these detectors are largely insensitive to neutral particles (at least at particle energies of interest), it is now possible to measure the radial distribution of neutral {open_quotes}radiated{close_quotes} power emissivity, by looking at the difference between these measurements and those obtained with standard bolometers. When neutrals are not important, we found a very good agreement between the AXUV detectors and standard bolometers. Examples of applications of these measurements to the study of edge H-mode dynamics, impurity injection, disruptions, and internal barrier formation, are described. Planned upgrades and new applications for Alcator C-Mod are also discussed. {copyright} {ital 1999 American Institute of Physics.}

  19. Multispecies density peaking in gyrokinetic turbulence simulations of low collisionality Alcator C-Mod plasmas

    Science.gov (United States)

    Mikkelsen, D. R.; Bitter, M.; Delgado-Aparicio, L.; Hill, K. W.; Greenwald, M.; Howard, N. T.; Hughes, J. W.; Rice, J. E.; Reinke, M. L.; Podpaly, Y.; Ma, Y.; Candy, J.; Waltz, R. E.

    2015-06-01

    Peaked density profiles in low-collisionality AUG and JET H-mode plasmas are probably caused by a turbulently driven particle pinch, and Alcator C-Mod experiments confirmed that collisionality is a critical parameter. Density peaking in reactors could produce a number of important effects, some beneficial, such as enhanced fusion power and transport of fuel ions from the edge to the core, while others are undesirable, such as lower beta limits, reduced radiation from the plasma edge, and consequently higher divertor heat loads. Fundamental understanding of the pinch will enable planning to optimize these impacts. We show that density peaking is predicted by nonlinear gyrokinetic turbulence simulations based on measured profile data from low collisionality H-mode plasma in Alcator C-Mod. Multiple ion species are included to determine whether hydrogenic density peaking has an isotope dependence or is influenced by typical levels of low-Z impurities, and whether impurity density peaking depends on the species. We find that the deuterium density profile is slightly more peaked than that of hydrogen, and that experimentally relevant levels of boron have no appreciable effect on hydrogenic density peaking. The ratio of density at r/a = 0.44 to that at r/a = 0.74 is 1.2 for the majority D and minority H ions (and for electrons), and increases with impurity Z: 1.1 for helium, 1.15 for boron, 1.3 for neon, 1.4 for argon, and 1.5 for molybdenum. The ion temperature profile is varied to match better the predicted heat flux with the experimental transport analysis, but the resulting factor of two change in heat transport has only a weak effect on the predicted density peaking.

  20. Neutral Transport Simulations of Gas Puff Imaging Experiments on Alcator C-Mod

    International Nuclear Information System (INIS)

    Visible imaging of gas puffs has been used on the Alcator C-Mod tokamak to characterize edge plasma turbulence, yielding data that can be compared with plasma turbulence codes. Simulations of these experiments with the DEGAS 2 Monte Carlo neutral transport code have been carried out to explore the relationship between the plasma fluctuations and the observed light emission. By imposing two-dimensional modulations on the measured time-average plasma density and temperature profiles, we demonstrate that the spatial structure of the emission cloud reflects that of the underlying turbulence. However, the photon emission rate depends on the plasma density and temperature in a complicated way, and no simple scheme for inferring the plasma parameters directly from the light emission patterns is apparent. The simulations indicate that excited atoms generated by molecular dissociation are a significant source of photons, further complicating interpretation of the gas puff imaging results.Visibl e imaging of gas puffs has been used on the Alcator C-Mod tokamak to characterize edge plasma turbulence, yielding data that can be compared with plasma turbulence codes. Simulations of these experiments with the DEGAS 2 Monte Carlo neutral transport code have been carried out to explore the relationship between the plasma fluctuations and the observed light emission. By imposing two-dimensional modulations on the measured time-average plasma density and temperature profiles, we demonstrate that the spatial structure of the emission cloud reflects that of the underlying turbulence. However, the photon emission rate depends on the plasma density and temperature in a complicated way, and no simple scheme for inferring the plasma parameters directly from the light emission patterns is apparent. The simulations indicate that excited atoms generated by molecular dissociation are a significant source of photons, further complicating interpretation of the gas puff imaging results

  1. Molybdenum emission from impurity-induced m= 1 snake-modes on the Alcator C-Mod tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Delgado-Aparicio, L. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540 (United States); MIT - Plasma Science and Fusion Center, Cambridge, Massachusetts 02139 (United States); Bitter, M.; Gates, D.; Hill, K.; Pablant, N. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540 (United States); Granetz, R.; Reinke, M.; Podpaly, Y.; Rice, J. [MIT - Plasma Science and Fusion Center, Cambridge, Massachusetts 02139 (United States); Beiersdorfer, P. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Sugiyama, L. [MIT - Laboratory for Nuclear Science, Cambridge, Massachusetts 02139 (United States)

    2012-10-15

    A suite of novel high-resolution spectroscopic imaging diagnostics has facilitated the identification and localization of molybdenum impurities as the main species during the formation and lifetime of m= 1 impurity-induced snake-modes on Alcator C-Mod. Such measurements made it possible to infer, for the first time, the perturbed radiated power density profiles from which the impurity density can be deduced.

  2. The Submillimeter Wave Electron Cyclotron Emission Diagnostic for the Alcator C-Mod Tokamak.

    Science.gov (United States)

    Hsu, Thomas C.

    This thesis describes the engineering design, construction, and operation of a high spatial resolution submillimeter wave diagnostic for electron temperature measurements on Alcator C-Mod. Alcator C-Mod is a high performance compact tokamak capable of producing diverted, shaped plasmas with a major radius of 0.67 meters, minor radius of 0.21 centimeters, plasma current of 3 MA. The maximum toroidal field is 9 Tesla on the magnetic axis. The ECE diagnostic includes three primary components: a 10.8 meter quasioptical transmission line, a rapid scanning Michelson interferometer, and a vacuum compatible calibration source. Due to the compact size and high field of the tokamak the ECE system was designed to have a spectral range from 100 to 1000 GHz with frequency resolution of 5 GHz and spatial resolution of one centimeter. The beamline uses all reflecting optical elements including two off-axis parabolic mirrors with diameters of 20 cm. and focal lengths of 2.7 meters. Techniques are presented for grinding and finishing the mirrors to sufficient surface quality to permit optical alignment of the system. Measurements of the surface figure confirm the design goal of 1/4 wavelength accuracy at 1000 GHz. Extensive broadband tests of the spatial resolution of the ECE system are compared to a fundamental mode Gaussian beam model, a three dimensional vector diffraction model, and a geometric optics model. The Michelson interferometer is a rapid scanning polarization instrument which has an apodized frequency resolution of 5 GHz and a minimum scan period of 7.5 milliseconds. The novel features of this instrument include the use of precision linear bearings to stabilize the moving mirror and active counterbalancing to reduce vibration. Beam collimation within the instrument is done with off-axis parabolic mirrors. The Michelson also includes a 2-50 mm variable aperture and two signal attenuators constructed from crossed wire grid polarizers. To make full use of the advantages

  3. Wide-frequency range, dynamic matching network and power system for the “Shoelace” radio frequency antenna on the Alcator C-Mod tokamak

    International Nuclear Information System (INIS)

    A wide-frequency range (50–300 kHz) power system has been implemented for use with a new RF antenna – the “Shoelace” antenna – built to drive coherent plasma fluctuations in the edge of the Alcator C-Mod tokamak. A custom, dynamically tunable matching network allows two commercial 1 kW, 50-Ω RF amplifiers to drive the low-impedance, inductive load presented by the antenna. This is accomplished by a discretely variable L-match network, with 81 independently selected steps available for each of the series and parallel legs of the matching configuration. A compact programmable logic device provides a control system that measures the frequency with better than 1 kHz accuracy and transitions to the correct tuning state in less than 1 ms. At least 85% of source power is dissipated in the antenna across the operational frequency range, with a minimum frequency slew rate of 1 MHz/s; the best performance is achieved in the narrower band from 80 to 150 kHz which is of interest in typical experiments. The RF frequency can be run with open-loop control, following a pre-programmed analog waveform, or phase-locked to track a plasma fluctuation diagnostic signal in real time with programmable phase delay; the amplitude control is always open-loop. The control waveforms and phase delay are programmed remotely. These tools have enabled first-of-a-kind measurements of the tokamak edge plasma system response in the frequency range and at the wave number at which coherent fluctuations regulate heat and particle transport through the plasma boundary

  4. Wide-frequency range, dynamic matching network and power system for the "Shoelace" radio frequency antenna on the Alcator C-Mod tokamak.

    Science.gov (United States)

    Golfinopoulos, Theodore; LaBombard, Brian; Burke, William; Parker, Ronald R; Parkin, William; Woskov, Paul

    2014-04-01

    A wide-frequency range (50-300 kHz) power system has been implemented for use with a new RF antenna - the "Shoelace" antenna - built to drive coherent plasma fluctuations in the edge of the Alcator C-Mod tokamak. A custom, dynamically tunable matching network allows two commercial 1 kW, 50-Ω RF amplifiers to drive the low-impedance, inductive load presented by the antenna. This is accomplished by a discretely variable L-match network, with 81 independently selected steps available for each of the series and parallel legs of the matching configuration. A compact programmable logic device provides a control system that measures the frequency with better than 1 kHz accuracy and transitions to the correct tuning state in less than 1 ms. At least 85% of source power is dissipated in the antenna across the operational frequency range, with a minimum frequency slew rate of 1 MHz/s; the best performance is achieved in the narrower band from 80 to 150 kHz which is of interest in typical experiments. The RF frequency can be run with open-loop control, following a pre-programmed analog waveform, or phase-locked to track a plasma fluctuation diagnostic signal in real time with programmable phase delay; the amplitude control is always open-loop. The control waveforms and phase delay are programmed remotely. These tools have enabled first-of-a-kind measurements of the tokamak edge plasma system response in the frequency range and at the wave number at which coherent fluctuations regulate heat and particle transport through the plasma boundary.

  5. Diagnosis of mildly relativistic electron velocity distributions by electron cyclotron emission in the Alcator C tokamak

    International Nuclear Information System (INIS)

    Mildly relativistic electron velocity distributions are diagnosed from measurements of the first few electron cyclotron emission harmonics in the Alcator C tokamak. The approach employs a vertical viewing chord through the center of the tokamak plasma terminating at a compact, high-performance viewing dump. The cyclotron emission spectra obtained in this way are dominated by frequency downshifts due to the relativistic mass increase, which discriminates the electrons by their total energy. In this way a one-to-one correspondence between the energy and the emission frequency is accomplished in the absence of harmonic superpositions. The distribution, described by f/sub p/, the line-averaged phase space density, and Λ, the anisotropy factor, is determined from the ratio of the optically thin harmonics or polarizations. Diagnosis of spectra in the second and the third harmonic range of frequencies obtained during lower hybrid heating, current drive, and low density ohmic discharges are carried out, using different methods depending on the degree of harmonic superposition present in the spectrum and the availability of more than one ratio measurement. Discussions of transient phenomena, the radiation temperature measurement from the optically thick first harmonic, and the measurements compared to the angular hard x-ray diagnostic results illuminate the capabilities of the vertically viewing electron cyclotron emission diagnostic

  6. Upgrade to the Gas Puff Imaging Diagnostic that Views Alcator C-Mod's Inboard Edge

    Science.gov (United States)

    Sierchio, J. M.; Terry, J. L.

    2012-10-01

    We describe an upgrade of Alcator C-Mod's Gas Puff Imaging system which views the inboard plasma edge and SOL along lines-of-sight that are approximately parallel to the local magnetic field. The views are arranged in a 2D (R,Z) array with ˜2.8 cm radial coverage and ˜2.4 cm poloidal coverage. 23 of 54 available views were coupled via fibers to individual interference filters and PIN photodiode detectors. We are in the process of upgrading the system in order to increase the sensitivity of the system by replacing the PIN photodiodes with a 4x8 array of Avalanche Photo-Diodes (APD). Light from 30 views is coupled to the single-chip APD array through a single interference filter. We expect an improvement in signal-to-noise ratio of more than 10x. The frequency response of the system will increase from ˜400 kHz to 1MHz. The dynamic range of the new system is manipulated by changing the high-voltages on the APDs. Test results of the detectors' channel-to-channel cross-talk, frequency response, and gain curves will be presented, along with schematics of the experimental setup. The upgraded system allows for more study of inboard edge fluctuations, including whether the quasi-coherent fluctuations observed in the outboard edge also exist inboard.

  7. The dynamics and structure of edge-localized-modes in Alcator C-Mod

    Energy Technology Data Exchange (ETDEWEB)

    Terry, J.L. [Plasma Science and Fusion Center, MIT, 175 Albany St., Cambridge, MA 02139 (United States)]. E-mail: terry@psfc.mit.edu; Cziegler, I. [Plasma Science and Fusion Center, MIT, 175 Albany St., Cambridge, MA 02139 (United States); Hubbard, A.E. [Plasma Science and Fusion Center, MIT, 175 Albany St., Cambridge, MA 02139 (United States); Snipes, J.A. [Plasma Science and Fusion Center, MIT, 175 Albany St., Cambridge, MA 02139 (United States); Hughes, J.W. [Plasma Science and Fusion Center, MIT, 175 Albany St., Cambridge, MA 02139 (United States); Greenwald, M.J. [Plasma Science and Fusion Center, MIT, 175 Albany St., Cambridge, MA 02139 (United States); LaBombard, B. [Plasma Science and Fusion Center, MIT, 175 Albany St., Cambridge, MA 02139 (United States); Lin, Y. [Plasma Science and Fusion Center, MIT, 175 Albany St., Cambridge, MA 02139 (United States); Phillips, P. [Fusion Research Center, University of Texas-Austin, Austin, TX 78712 (United States); Wukitch, S. [Plasma Science and Fusion Center, MIT, 175 Albany St., Cambridge, MA 02139 (United States)

    2007-06-15

    Characteristics of discrete ELMs produced in Alcator C-Mod discharges of low edge collisionality (0.2 < {nu} {sup *} < 1) and large lower triangularity ({delta} {sub lower} {approx} 0.75) are examined. The energy lost per ELM from the H-mode pedestal is {approx}10% of the pedestal energy. These ELMs exhibit relatively long-lived precursor oscillations, often with two modes of intermediate toroidal mode number present. At the ELM 'crash' multiple plasma filament structures are expelled into the scrape-off-layer. A short-lived high frequency ({approx}0.5 MHz) magnetic oscillation is initiated at the 'crash'. The initial ELM filaments are large perturbations to the SOL with radial extents of 0.5-1 cm and typical radial propagation velocities of 1 km/s. Velocities of up to 8 km/s have been seen. The poloidal extent of the initial filaments is >4.5 cm. The initial filaments are followed (at intervals of {approx}100 {mu}s) by multiple, less perturbing secondary filaments.

  8. Long Term Retention of Deuterium and Tritium in Alcator C-Mod

    International Nuclear Information System (INIS)

    We estimate the total in-vessel deuterium retention in Alcator C-Mod from a run campaign of about 1090 plasmas. The estimate is based on measurements of deuterium retained on 22 molybdenum tiles from the inner wall and divertor. The areal density of deuterium on the tiles was measured by nuclear reaction analysis. From these data, the in-vessel deuterium inventory is estimated to be about 0.1 gram, assuming the deuterium coverage is toroidally symmetric. Most of the retained deuterium is on the walls of the main plasma chamber, only about 2.5% of the deuterium is in the divertor. The D coverage is consistent with a layer saturated by implantation with ions and charge-exchange neutrals from the plasma. This contrasts with tokamaks with carbon plasma-facing components (PFC's) where long-term retention of tritium and deuterium is large and mainly in the divertor due to codeposition with carbon eroded by the plasma. The low deuterium retention in the C-Mod divertor is mainly due to the absence of carbon PFC's in C-Mod and the low erosion rate of Mo

  9. Characterization of enhanced D{alpha} high-confinement modes in Alcator {ital C}-Mod

    Energy Technology Data Exchange (ETDEWEB)

    Greenwald, M.; Boivin, R.; Bonoli, P.; Budny, R.; Fiore, C.; Goetz, J.; Granetz, R.; Hubbard, A.; Hutchinson, I.; Irby, J.; LaBombard, B.; Lin, Y.; Lipschultz, B.; Marmar, E.; Mazurenko, A.; Mossessian, D.; Sunn Pedersen, T.; Pitcher, C.S.; Porkolab, M.; Rice, J.; Rowan, W.; Snipes, J.; Schilling, G.; Takase, Y.; Terry, J.; Wolfe, S.; Weaver, J.; Welch, B.; Wukitch, S. [MIT-Plasma Science and Fusion Center, Cambridge, Massachusetts 02139 (United States)

    1999-05-01

    Regimes of high-confinement mode have been studied in the Alcator {ital C}-Mod tokamak [Hutchinson {ital et al.}, Phys. Plasmas {bold 1}, 1511 (1994)]. Plasmas with no edge localized modes (ELM-free) have been compared in detail to a new regime, enhanced D{alpha} (EDA). EDA discharges have only slightly lower energy confinement than comparable ELM-free ones, but show markedly reduced impurity confinement. Thus EDA discharges do not accumulate impurities and typically have a lower fraction of radiated power. The edge gradients in EDA seem to be relaxed by a continuous process rather than an intermittent one as is the case for standard ELMy discharges and thus do not present the first wall with large periodic heat loads. This process is probably related to fluctuations seen in the plasma edge. EDA plasmas are more likely at low plasma current (q{gt}3.7), for moderate plasma shaping, (triangularity {approximately}0.35{endash}0.55), and for high neutral pressures. As observed in soft x-ray emission, the pedestal width is found to scale with the same parameters that determine the EDA/ELM-free boundary. {copyright} {ital 1999 American Institute of Physics.}

  10. Investigation of performance limiting phenomena in a variable phase ICRF antenna in Alcator C-Mod

    Energy Technology Data Exchange (ETDEWEB)

    Wukitch, S J [MIT Plasma Science and Fusion Center, Cambridge, MA 02139 (United States); Boivin, R L [General Atomics, San Diego, CA 92186 (United States); Bonoli, P T [MIT Plasma Science and Fusion Center, Cambridge, MA 02139 (United States); Goetz, J A [University of Wisconsin, Madison, WI 53706 (United States); Irby, J [MIT Plasma Science and Fusion Center, Cambridge, MA 02139 (United States); Hutchinson, I [MIT Plasma Science and Fusion Center, Cambridge, MA 02139 (United States); Lin, Y [MIT Plasma Science and Fusion Center, Cambridge, MA 02139 (United States); Parisot, A [MIT Plasma Science and Fusion Center, Cambridge, MA 02139 (United States); Porkolab, M [MIT Plasma Science and Fusion Center, Cambridge, MA 02139 (United States); Marmar, E [MIT Plasma Science and Fusion Center, Cambridge, MA 02139 (United States); Schilling, G [Princeton Plasma Physics Laboratory, Princeton, NJ 08543 (United States); Wilson, J R [Princeton Plasma Physics Laboratory, Princeton, NJ 08543 (United States)

    2004-09-01

    High power density, phased antenna operation can often be limited by antenna voltage handling and/or impurity and density production. Using a pair of two-strap antennas for comparison, the performance of a four-strap, fast wave antenna is assessed for a variety of configurations and antenna phases in Alcator C-Mod. To obtain robust voltage handling, the antenna was reconfigured to eliminate regions where the RF E-field is parallel to B or to reduce the RF E-field to <1.0 MV m{sup -1}. To limit impurity generation, BN tiles were used to replace the original Mo tiles, a BN clad septum was inserted to limit field line connection length, and BN-metal interfaces were shielded from the plasma. With these modifications, the antenna heating efficiency and impurity generation are nearly identical to those of the two-strap antennas and independent of antenna phase in L-mode discharges. This antenna has achieved 11 MW m{sup -2} in both heating and current drive phases in both L-mode and H-mode discharges.

  11. Measurements of the high confinement mode pedestal region on Alcator C-Mod

    Energy Technology Data Exchange (ETDEWEB)

    Hubbard, A.E.; Boivin, R.L.; Granetz, R.S.; Greenwald, M.; Hutchinson, I.H.; Irby, J.H.; In, Y.; Kesner, J.; LaBombard, B.; Lin, Y.; Rice, J.E.; Sunn Pedersen, T.; Snipes, J.A.; Stek, P.C.; Takase, Y.; Wolfe, S.M.; Wukitch, S. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    1998-05-01

    Measurements of the steep transport barrier at the edge of the Alcator C-Mod tokamak [I. H. Hutchinson {ital et al.}, Phys. Plasmas {bold 1}, 1511 (1994)] are presented. The parameters at the top of this barrier are in the range T{sub e}=150{endash}750 eV and n{sub e}=0.5{minus}3.3{times}10{sup 20} m{sup {minus}3}, depending on the confinement regime. Type III edge localized modes (ELMs) have an upper temperature limit. T{sub e} pedestal profiles show a barrier width {Delta}{sub T}{approx_equal}8 mm. Soft x-ray emissivity profiles are narrower, with {Delta}=2{endash}4 mm. Edge currents are calculated to alter the ideal stability boundary favorably, leading to ideally stable pedestal profiles. High frequency, broadband, edge density fluctuations are sometimes observed in H-mode (high-confinement mode) and are associated with enhanced particle transport. Coherent magnetic fluctuations localized near the pedestal are also seen. {copyright} {ital 1998 American Institute of Physics.}

  12. Analysis of 4-strap ICRF Antenna Performance in Alcator C-Mod

    Energy Technology Data Exchange (ETDEWEB)

    G. Schilling; S.J. Wukitch; R.L. Boivin; J.A. Goetz; J.C. Hosea; J.H. Irby; Y. Lin; A. Parisot; M. Porkolab; J.R. Wilson; the Alcator C-Mod Team

    2003-07-31

    A 4-strap ICRF antenna was designed and fabricated for plasma heating and current drive in the Alcator C-Mod tokamak. Initial upgrades were carried out in 2000 and 2001, which eliminated surface arcing between the metallic protection tiles and reduced plasma-wall interactions at the antenna front surface. A boron nitride septum was added at the antenna midplane to intersect electric fields resulting from radio-frequency sheath rectification, which eliminated antenna corner heating at high power levels. The current feeds to the radiating straps were reoriented from an E||B to E parallel B geometry, avoiding the empirically observed {approx}15 kV/cm field limit and raising antenna voltage holding capability. Further modifications were carried out in 2002 and 2003. These included changes to the antenna current strap, the boron nitride tile mounting geometry, and shielding the BN-metal interface from the plasma. The antenna heating efficiency, power, and voltage characteristics under these various configurations will be presented.

  13. Upgrades to the 4-strap ICRF Antenna in Alcator C-Mod

    Energy Technology Data Exchange (ETDEWEB)

    G. Schilling; J.C. Hosea; J.R. Wilson; W. Beck; R.L. Boivin; P.T. Bonoli; D. Gwinn; W.E. Lee; E. Nelson-Melby; M. Porkolab; R. Vieira; S.J. Wukitch; and J.A. Goetz

    2001-06-12

    A 4-strap ICRF antenna suitable for plasma heating and current drive has been designed and fabricated for the Alcator C-Mod tokamak. Initial operation in plasma was limited by high metallic impurity injection resulting from front surface arcing between protection tiles and from current straps to Faraday shields. Antenna modifications were made in February 2000, resulting in impurity reduction, but low-heating efficiency was observed when the antenna was operated in its 4-strap rather than a 2-strap configuration. Further modifications were made in July 2000, with the installation of BN plasma-facing tiles and radio- frequency bypassing of the antenna backplane edges and ends to reduce potential leakage coupling to plasma surface modes. Good heating efficiency was now observed in both heating configurations, but coupled power was limited to 2.5 MW in H-mode, 3 MW in L-mode, by plasma-wall interactions. Additional modifications were started in February 2001 and will be completed by this meeting. All the above upgrades and their effect on antenna performance will be presented.

  14. Effects of neutral particles on edge dynamics in Alcator C-Mod plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Boivin, R. L. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Goetz, J. A. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Hubbard, A. E. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Hughes, J. W. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Hutchinson, I. H. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Irby, J. H. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); LaBombard, B. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Marmar, E. S. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Mossessian, D. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Pitcher, C. S. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)] (and others)

    2000-05-01

    Neutral particle densities and energy losses have been measured in the Alcator C-Mod tokamak [Hutchinson et al., Phys. Plasmas 1, 1511 (1994)]. Their effect on the formation and evolution of the edge barrier which accompanies the enhanced confinement regime are discussed. The neutrals can enter the edge dynamics through the particle, momentum, and energy balance. Neutral densities of up to 5x10{sup 16} m{sup -3} have been measured in the edge barrier region. Neutrals enter the local dynamics around most of the periphery, not just at the X-point. High resolution measurements of the ionization profile have been obtained for the region near the separatrix. The profile shifts inside the separatrix as the plasma is making a transition from low-to high-mode confinement (H-mode) regimes, partly accounting for the dramatic rise in edge density. The measured neutral density is large enough to affect the bulk ion momentum by charge exchange, and thereby introduces a negative radial electric field at the edge. At the same time, significant edge heat flux, carried by the neutrals, contributes to the measured power loss. At very high edge densities, this loss mechanism could contribute to quenching H-modes. (c) 2000 American Institute of Physics.

  15. High resolution visible continuum imaging diagnostic on the Alcator C-Mod tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Marmar, E. S.; Boivin, R. L.; Granetz, R. S.; Hughes, J. W.; Lipschultz, B.; McCool, S.; Mossessian, D.; Pitcher, C. S.; Rice, J. E.; Terry, J. L.

    2001-01-01

    A high spatial resolution CCD based one-dimensional imaging system to measure visible continuum emissivity profiles from Alcator C-Mod tokamak plasmas is described. The instrument has chordal resolution that is better than 1 mm for the edge region of the plasma, where very sharp (1 to 10 mm) gradient lengths in plasma parameters are observed after the formation of the H-mode transport barrier. Each image has up to 2048 pixels, and total spatial coverage goes from 2 cm inside of the magnetic axis to {approx}4 cm outside of the last closed flux surface in the {approx}22 cm horizontal minor radius plasmas. Time resolution can be varied from 0.21 ms to 4 ms; good signal to noise is achieved with 1 ms integration under typical plasma conditions. The emission over most of the plasma volume is dominated by free--free bremsstrahlung, and can be used to infer local values of the average ion charge (Z{sub eff}). Toroidally localized puffing of deuterium, nitrogen, and helium reveals that a significant contribution to the signal in the scrape-off layer at the extreme edge of the plasma can come from diatomic molecular band pseudocontinuum emission.

  16. Scaling and transport analysis of divertor conditions on the Alcator C-Mod tokamak

    Energy Technology Data Exchange (ETDEWEB)

    LaBombard, B.; Goetz, J.; Kurz, C.; Jablonski, D.; Lipschultz, B.; McCracken, G.; Niemczewski, A.; Boivin, R.L.; Bombarda, F.; Christensen, C.; Fairfax, S.; Fiore, C.; Garnier, D.; Graf, M.; Golovato, S.; Granetz, R.; Greenwald, M.; Horne, S.; Hubbard, A.; Hutchinson, I.; Irby, J.; Kesner, J.; Luke, T.; Marmar, E.; May, M.; O`Shea, P.; Porkolab, M.; Reardon, J.; Rice, J.; Schachter, J.; Snipes, J.; Stek, P.; Takase, Y.; Terry, J.; Tinios, G.; Watterson, R.; Welch, B.; Wolfe, S. [Plasma Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    1995-06-01

    Detailed measurements and transport analysis of divertor conditions in Alcator C-Mod [Phys. Plasmas {bold 1}, 1511 (1994)] are presented for a range of line-averaged densities, 0.7{lt}{ital {bar n}}{sub {ital e}}{lt}2.2{times}10{sup 20} m{sup {minus}3}. Three parallel heat transport regimes are evident in the scrape-off layer: sheath-limited conduction, high-recycling divertor, and detached divertor, which can coexist in the same discharge. {ital Local} cross-field pressure gradients are found to scale simply with a {ital local} electron temperature. This scaling is consistent with classical electron parallel conduction being balanced by anomalous cross-field transport ({chi}{sub {perpendicular}}{similar_to}0.2 m{sup 2} s{sup {minus}1}) proportional to the local pressure gradient. A 60%--80% of divertor power is radiated in attached discharges, approaching 100% in detached discharges. Detachment occurs when the heat flux to the plate is low and the plasma pressure is high ({ital T}{sub {ital e}}{similar_to}5 eV). High neutral pressures in the divertor are nearly always present (1--20 mTorr), sufficient to remove parallel momentum via ion--neutral collisions.

  17. Measurement of the current density profile in the Alcator C tokamak using lithium pellets

    International Nuclear Information System (INIS)

    High-speed lithium pellets have been injected into Alcator C tokamak plasmas in order to measure the internal magnetic field, and thus current density profiles. In the pellet ablation cloud, intense visible line radiation from the Li+ ion (λ∼5485 A, 1s2s 3S-1s2p 3P) is polarized due to the Zeeman effect, and measurement of the polarization angle yields the direction of the total local magnetic field. A ''snap shot'' of the q profile is obtained as the pellet penetrates from the edge into the center of the discharge, in a time of about 300 μs. The spatial resolution of the measurement is about 1 cm. At a toroidal field of BT=10 T, the emission in the unshifted π component of the Zeeman triplet is more than 80% polarized, and q profiles have been obtained. The pellets are perturbative (left-angle Δne right-angle/left-angle ne right-angle ∼1), but the total pellet penetration time is at least a factor of 1000 smaller than the classical skin time. It can thus be anticipated that the current density profile should not be perturbed significantly during the time of the measurement. With some relatively straightforward modifications and refinements, precision approaching 10% for the measurement of q profiles should be achievable. The technique appears viable, using Li, as long as the toroidal field is approx-gt 4 T

  18. Soft x-ray tomography diagnostic for the Alcator C tokamak

    International Nuclear Information System (INIS)

    A soft x-ray tomography diagnostic has been built and operated on the Alcator C tokamak with the use of an 80-channel array of detectors. The detector system consists of miniature PIN photodiodes which are located around the periphery of the plasma at one toroidal location (top and bottom ports) in order to image the poloidal cross section of the plasma's soft x-ray emissivity. The compact size and inexpensive cost of these detectors allow for the large number of views required to avoid any assumptions about plasma rotation, position, or symmetry in the reconstruction algorithm. The use of logarithmic amplifiers in the electronic circuitry makes it possible to record conveniently data from a wide range of plasma operating parameters. This diagnostic has been used to study plasma position and shape, magnetohydrodynamic (MHD) phenomena, and the effects of impurities. Data from a pellet-fueled discharge exhibiting large-scale MHD activity are presented. The system has recently been expanded to 128 detectors with the addition of an array on a side port in order to improve its coverage of the plasma and the resolution of the reconstructions

  19. Measurement of LHCD edge power deposition through modulation techniques on Alcator C-Mod

    Energy Technology Data Exchange (ETDEWEB)

    Faust, I. C.; Brunner, D.; LaBombard, B.; Parker, R. R.; Baek, S. G.; Chilenksi, M. A.; Hubbard, A.; Hughes, J. W.; Terry, J. L.; Shiraiwa, S.; Walk, J. R.; Wallace, G. M.; Whyte, D. G. [MIT Plasma Science and Fusion Center, Cambridge, MA USA (United States); Edlund, E. [Princeton Plasma Physics Laboratory, Princeton, NJ USA (United States)

    2015-12-10

    The efficiency of LHCD on Alcator C-Mod drops exponentially with line average density. At reactor relevant densities (> 1 · 1020 [m{sup −3}]) no measurable current is driven. While a number of causes have been suggested, no specific mechanism has been shown to be responsible for the loss of current drive at high density. Fast modulation of the LH power was used to isolate and quantify the LHCD deposition within the plasma. Measurements from these plasmas provide unique evidence for determining a root cause. Modulation of LH power in steady plasmas exhibited no correlated change in the core temperature. A correlated, prompt response in the edge suggests that the loss in efficiency is related to a edge absorption mechanism. This follows previous results which found the generation of n{sub ||}-independent SOL currents. Multiple Langmuir probe array measurements of the conducted heat conclude that the lost power is deposited near the last closed flux surface. The heat flux induced by LH waves onto the outer divertor is calculated. Changes in the neutral pressure, ionization and hard X-ray emission at high density highlight the importance of the active divertor in the loss of efficiency. Results of this study implicate a mechanism which may occur over multiple passes, leading to power absorption near the LCFS.

  20. Experimental studies of edge turbulence and confinement in Alcator C-Moda)

    Science.gov (United States)

    Cziegler, I.; Terry, J. L.; Hughes, J. W.; LaBombard, B.

    2010-05-01

    The steep gradient edge region and scrape-off-layer (SOL) on the low-field-side of Alcator C-Mod [I. H. Hutchinson, R. Boivin, F. Bombarda et al., Phys. Plasmas 1, 1511 (1994)] tokamak plasmas are studied using gas-puff-imaging diagnostics. In L-mode plasmas, the region extending ˜2 cm inside the magnetic separatrix has fluctuations showing a broad, turbulent spectrum, propagating in the electron diamagnetic drift direction, whereas features in the open field line region propagate in the ion diamagnetic drift direction. This structure is robust against toroidal field strength, poloidal null-point geometry, plasma current, and plasma density. Global parameter dependence of spectral and spatial structure of the turbulence inside the separatrix is explored and characterized, and both the intensity and spectral distributions are found to depend strongly on the plasma density normalized to the tokamak density limit. In H-mode discharges the fluctuations at and inside the magnetic separatrix show fundamentally different trends compared to L-mode, with the electron diamagnetic direction propagating turbulence greatly reduced in ELM-free [F. Wagner et al., Proceedings of the Thirteenth Conference on Plasma Physics and Controlled Nuclear Fusion Research (IAEA, Vienna, 1982), Vol. I, p. 277], and completely dominated by the modelike structure of the quasicoherent mode in enhanced D-alpha regimes [A. E. Hubbard, R. L. Boivin, R. S. Granetz et al., Phys. Plasmas 8, 2033 (2001)], while the normalized SOL turbulence is largely unaffected.

  1. A new interferometry-based electron density fluctuation diagnostic on Alcator C-Moda)

    Science.gov (United States)

    Kasten, C. P.; Irby, J. H.; Murray, R.; White, A. E.; Pace, D. C.

    2012-10-01

    The two-color interferometry diagnostic on the Alcator C-Mod tokamak has been upgraded to measure fluctuations in the electron density and density gradient for turbulence and transport studies. Diagnostic features and capabilities are described. In differential mode, fast phase demodulation electronics detect the relative phase change between ten adjacent, radially-separated (ΔR = 1.2 cm, adjustable), vertical-viewing chords, which allows for measurement of the line-integrated electron density gradient. The system can be configured to detect the absolute phase shift of each chord by comparison to a local oscillator, measuring the line-integrated density. Each chord is sensitive to density fluctuations with kR < 20.3 cm-1 and is digitized at up to 10 MS/s, resolving aspects of ion temperature gradient-driven modes and other long-wavelength turbulence. Data from C-Mod discharges is presented, including observations of the quasi-coherent mode in enhanced D-alpha H-mode plasmas and the weakly coherent mode in I-mode.

  2. Spectroscopic measurement of impurity transport coefficients and penetration efficiencies in Alcator C-Mod plasmas

    Science.gov (United States)

    Graf, M. A.; Rice, J. E.; Terry, J. L.; Marmar, E. S.; Goetz, J. A.; McCracken, G. M.; Bombarda, F.; May, M. J.

    1995-01-01

    Impurity transport coefficients and the penetration efficiencies of intrinsic and injected impurities through the separatrix of diverted Alcator C-Mod discharges have been measured using x-ray and vacuum ultraviolet (VUV) spectroscopic diagnostics. The dominant low Z intrinsic impurity in C-Mod is carbon which is found to be present in concentrations of less than 0.5%. Molybdenum, from the plasma facing components, is the dominant high Z impurity and is typically found in concentrations of about 0.02%. Trace amounts of medium and high Z nonrecycling impurities can be injected at the midplane using the laser blow-off technique and calibrated amounts of recycling, gaseous impurities can be introduced through fast valves either at the midplane or at various locations in the divertor chamber. A five chord crystal x-ray spectrometer array with high spectral resolution is used to provide spatial profiles of high charge state impurities. An absolutely calibrated, grazing incidence VUV spectrograph with high time resolution and a broad spectral range allows for the simultaneous measurement of many impurity lines. Various filtered soft x-ray diode arrays allow for spatial reconstructions of plasma emissivity. The observed brightnesses and emissivities from a number of impurity lines are used together with the mist transport code and a collisional-radiative atomic physics model to determine charge state density profiles and impurity transport coefficients. Comparisons of the deduced impurity content with the measured Zeff and total radiated power of the plasma are made.

  3. Advanced Tokamak Regimes in Alcator C-Mod with Lower Hybrid Current Drive

    Science.gov (United States)

    Parker, R.; Bonoli, P.; Gwinn, D.; Hutchinson, I.; Porkolab, M.; Ramos, J.; Bernabei, S.; Hosea, J.; Wilson, R.

    1999-11-01

    Alcator C-Mod has been proposed as a test-bed for developing advanced tokamak scenarios owing to its strong shaping, relatively long pulse length capability at moderate field, e.g. t ~ L/R at B = 5T and T_eo ~ 7keV, and the availability of strong ICRF heating. We plan to exploit this capability by installing up to 4 MW RF power at 4.6 GHz for efficient off-axis current drive by lower hybrid waves. By launching LH waves with a grill whose n_xx spectrum can be dynamically controlled over the range 2 2. Such reversed or nearly zero shear regimes have already been proposed as the basis of an advanced tokamak burning-plasma experiment-ATBX (M. Porkolab et al, IAEA-CN-69/FTP/13, IAEA,Yokohama 1998.), and could provide the basis for a demonstration power reactor. Theoretical and experimental basis for this advanced tokamak research program on C-Mod, including design of the lower hybrid coupler, its spectrum and current drive capabilities will be presented.

  4. Upgrades to the 4-strap ICRF antenna in Alcator C-Mod

    Science.gov (United States)

    Schilling, G.; Hosea, J. C.; Wilson, J. R.; Beck, W.; Boivin, R. L.; Bonoli, P. T.; Gwinn, D.; Lee, W. D.; Nelson-Melby, E.; Porkolab, M.; Vieira, R.; Wukitch, S. J.; Goetz, J. A.

    2001-10-01

    A 4-strap ICRF antenna suitable for plasma heating and current drive has been designed and fabricated for the Alcator C-Mod tokamak. Initial operation in plasma was limited by high metallic impurity injection resulting from front surface arcing between protection tiles and from current straps to Faraday shields. Antenna modifications were made in 2/2000, resulting in impurity reduction, but low heating efficiency was observed when the antenna was operated in its 4-strap rather than a 2-strap configuration. Further modifications were made in 7/2000, with the installation of BN plasma-facing tiles and radiofrequency bypassing of the antenna backplane edges and ends to reduce potential leakage coupling to plasma surface modes. Good heating efficiency was now observed in both heating configurations, but coupled power was limited to 2.5 MW in H-mode, 3 MW in L-mode, by plasma-wall interactions. Additional modifications were started in 2/2001 and will be completed by this meeting. All the above upgrades and their effect on antenna performance will be presented.

  5. A fast neutron spectrometer for D-D fusion neutron measurements at the Alcator C tokamak

    Science.gov (United States)

    Fisher, W. A.; Chen, S. H.; Gwinn, D.; Parker, R. R.

    1984-01-01

    A neutron spectrometer using a high pressure 3He ionization chamber has been designed and used to measure the neutron spectrum from an ohmically heated deuterium plasma. The resolution of the spectrometer at 2.45 MeV is determine to be 46 keV full width at half-maximum (fwhm). Particular attention has been paid to optimizing the detector shielding and collimation to reject thermal and epithermal neutrons scattered from the tokamak structure. As a result, measurements indicate that the ratio of the number of counts in the 2.45 MeV peak to the total number of detected neutron events is {1}/{67}. For the 8 μs amplifier time constant used, a count rate as high as 44 counts per second has been achieved in the thermonuclear peak. The observed spectra have been compared with calculated spectra using the MCNP Monte Carlo Neutral Particle Transport code and they show good agreement. There is little evidence of neutrons produced from photoneutron reactions or electrodisintegration. It has been possible to confirm that the shape of the thermonuclear peak is consistent with the Gaussian shape predicted and that the ion temperature as determined from the line width is consistent with other Alcator C ion temperature diagnostics, and follows the trends predicted by the theory of Doppler line broadening.

  6. Robotic calibration of the motional Stark effect diagnostic on Alcator C-Mod

    Science.gov (United States)

    Mumgaard, Robert T.; Scott, Steven D.; Ko, Jinseok

    2014-05-01

    The capability to calibrate diagnostics, such as the Motional Stark Effect (MSE) diagnostic, without using plasma or beam-into-gas discharges will become increasingly important on next step fusion facilities due to machine availability and operational constraints. A robotic calibration system consisting of a motorized three-axis positioning system and a polarization light source capable of generating arbitrary polarization states with a linear polarization angle accuracy of deployed on Alcator C-Mod. The polarization response of the complex diagnostic is shown to be fully captured using a Fourier expansion of the detector signals in terms of even harmonics of the input polarization angle. The system's high precision robotic control of position and orientation allow it to be used also to calibrate the geometry of the instrument's view. Combined with careful measurements of the narrow bandpass spectral filters, this system fully calibrates the diagnostic without any plasma discharges. The system's high repeatability, flexibility, and speed has been exploited to quantify several systematics in the MSE diagnostic response, providing a more complete understanding of the diagnostic performance.

  7. Understanding of Neutral Gas Transport in the Alcator C-Mod Tokamak Divertor

    Energy Technology Data Exchange (ETDEWEB)

    D.P. Stotler; C.S. Pitcher; C.J. Boswell; B. LaBombard; J.L. Terry; J.D. Elder; S. Lisgo

    2002-05-07

    A series of experiments on the effect of divertor baffling on the Alcator C-Mod tokamak provides stringent tests on models of neutral gas transport in and around the divertor region. One attractive feature of these experiments is that a trial description of the background plasma can be constructed from experimental measurements using a simple model, allowing the neutral gas transport to be studied with a stand-alone code. The neutral-ion and neutral-neutral elastic scattering processes recently added to the DEGAS 2 Monte Carlo neutral transport code permit the neutral gas flow rates between the divertor and main chamber to be simulated more realistically than before. Nonetheless, the simulated neutral pressures are too low and the deuterium Balmer-alpha emission profiles differ qualitatively from those measured, indicating an incomplete understanding of the physical processes involved in the experiment. Some potential explanations are examined and opportunities for future exploration a re highlighted. Improvements to atomic and surface physics data and models will play a role in the latter.

  8. Visible continuum measurements on the Alcator C Tokamak: Changes in particle transport during pellet fuelled discharges

    International Nuclear Information System (INIS)

    A spatially resolving visible light detector system is used to measure continuum radiation near 5360A on the Alcator C Tokamak. For the typically hot plasmas studied, the continuum emission is found to be dominated by bremsstrahlung radiation near this wavelength region. Accurate determinations of Z/sub eff/ are obtained from continuum measurements using independently determined temperature and density measurements. Density profiles during high density, clean pellet fueled discharges, are also determined and are used to study the changes in particle transport after injection. For discharges with sufficiently large pellet density increases, density profiles are found to become more peaked following the injection. In these cases, the profiles are found to remain peaked for the remainder of the discharge, or until a ''giant'' sawtooth or minor disruption abruptly returns the profiles to a flatter pre-pellet condition. Analysis of density profiles after pellet injection yields information about the radial diffusion and convection velocity of the plasma particles. The peakedness in the density profiles, observed after pellet injection, is attributable mostly to increases in inward convection. It is concluded that neoclassical fluxes are too small to account for these changes. 70 refs., 55 figs

  9. The multi-spectral line-polarization MSE system on Alcator C-Mod

    Science.gov (United States)

    Mumgaard, R. T.; Scott, S. D.; Khoury, M.

    2016-11-01

    A multi-spectral line-polarization motional Stark effect (MSE-MSLP) diagnostic has been developed for the Alcator C-Mod tokamak wherein the Stokes vector is measured in multiple wavelength bands simultaneously on the same sightline to enable better polarized background subtraction. A ten-sightline, four wavelength MSE-MSLP detector system was designed, constructed, and qualified. This system consists of a high-throughput polychromator for each sightline designed to provide large étendue and precise spectral filtering in a cost-effective manner. Each polychromator utilizes four narrow bandpass interference filters and four custom large diameter avalanche photodiode detectors. Two filters collect light to the red and blue of the MSE emission spectrum while the remaining two filters collect the beam pi and sigma emission generated at the same viewing volume. The filter wavelengths are temperature tuned using custom ovens in an automated manner. All system functions are remote controllable and the system can be easily retrofitted to existing single-wavelength line-polarization MSE systems.

  10. Understanding of Neutral Gas Transport in the Alcator C-Mod Tokamak Divertor

    International Nuclear Information System (INIS)

    A series of experiments on the effect of divertor baffling on the Alcator C-Mod tokamak provides stringent tests on models of neutral gas transport in and around the divertor region. One attractive feature of these experiments is that a trial description of the background plasma can be constructed from experimental measurements using a simple model, allowing the neutral gas transport to be studied with a stand-alone code. The neutral-ion and neutral-neutral elastic scattering processes recently added to the DEGAS 2 Monte Carlo neutral transport code permit the neutral gas flow rates between the divertor and main chamber to be simulated more realistically than before. Nonetheless, the simulated neutral pressures are too low and the deuterium Balmer-alpha emission profiles differ qualitatively from those measured, indicating an incomplete understanding of the physical processes involved in the experiment. Some potential explanations are examined and opportunities for future exploration a re highlighted. Improvements to atomic and surface physics data and models will play a role in the latter

  11. BOUT++ Simulations of Edge Turbulence in Alcator C-Mod's EDA H-Mode

    Science.gov (United States)

    Davis, E. M.; Porkolab, M.; Hughes, J. W.; Labombard, B.; Snyder, P. B.; Xu, X. Q.

    2013-10-01

    Energy confinement in tokamaks is believed to be strongly controlled by plasma transport in the pedestal. The pedestal of Alcator C-Mod's Enhanced Dα (EDA) H-mode (ν* > 1) is regulated by a quasi-coherent mode (QCM), an edge fluctuation believed to reduce particle confinement and allow steady-state H-mode operation. ELITE calculations indicate that EDA H-modes sit well below the ideal peeling-ballooning instability threshold, in contrast with ELMy H-modes. Here, we use a 3-field reduced MHD model in BOUT++ to study the effects of nonideal and nonlinear physics on EDA H-modes. In particular, incorporation of realistic pedestal resistivity is found to drive resistive ballooning modes (RBMs) and increase linear growth rates above the corresponding ideal rates. These RBMs may ultimately be responsible for constraining the EDA pedestal gradient. However, recent high-fidelity mirror Langmuir probe measurements indicate that the QCM is an electron drift-Alfvén wave - not a RBM. Inclusion of the parallel pressure gradient term in the 3-field reduced MHD Ohm's law and various higher field fluid models are implemented in an effort to capture this drift wave-like response. This work was performed under the auspices of the USDoE under awards DE-FG02-94-ER54235, DE-AC52-07NA27344, DE-AC52-07NA27344, and NNSA SSGF.

  12. Kinetic modeling of divertor heat load fluxes in the Alcator C-Mod and DIII-D tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Pankin, A. Y. [Tech-X Corporation, Boulder, Colorado 80303 (United States); Rafiq, T.; Kritz, A. H. [Department of Physics, Lehigh University, Bethlehem, Pennsylvania 18015 (United States); Park, G. Y. [National Fusion Research Institute, Daejeon, 305-333 (Korea, Republic of); Chang, C. S.; Ku, S. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540 (United States); Brunner, D.; Hughes, J. W.; LaBombard, B.; Terry, J. L. [MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139 (United States); Groebner, R. J. [General Atomics, San Diego, California 92121 (United States)

    2015-09-15

    The guiding-center kinetic neoclassical transport code, XGC0 [Chang et al., Phys. Plasmas 11, 2649 (2004)], is used to compute the heat fluxes and the heat-load width in the outer divertor plates of Alcator C-Mod and DIII-D tokamaks. The dependence of the width of heat-load fluxes on neoclassical effects, neutral collisions, and anomalous transport is investigated using the XGC0 code. The XGC0 code includes realistic X-point geometry, a neutral source model, the effects of collisions, and a diffusion model for anomalous transport. It is observed that the width of the XGC0 neoclassical heat-load is approximately inversely proportional to the total plasma current I{sub p.} The scaling of the width of the divertor heat-load with plasma current is examined for an Alcator C-Mod discharge and four DIII-D discharges. The scaling of the divertor heat-load width with plasma current is found to be weaker in the Alcator C-Mod discharge compared to scaling found in the DIII-D discharges. The effect of neutral collisions on the 1/I{sub p} scaling of heat-load width is shown not to be significant. Although inclusion of poloidally uniform anomalous transport results in a deviation from the 1/I{sub p} scaling, the inclusion of the anomalous transport that is driven by ballooning-type instabilities results in recovering the neoclassical 1/I{sub p} scaling. The Bohm or gyro-Bohm scalings of anomalous transport do not strongly affect the dependence of the heat-load width on plasma current. The inclusion of anomalous transport, in general, results in widening the width of neoclassical divertor heat-load and enhances the neoclassical heat-load fluxes on the divertor plates. Understanding heat transport in the tokamak scrape-off layer plasmas is important for strengthening the basis for predicting divertor conditions in ITER.

  13. Lithium pellet injection experiments on the Alcator C-Mod tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Garnier, D.T.

    1996-06-01

    A pellet enhanced performance mode, showing significantly reduced core transport, is regularly obtained after the injection of deeply penetrating lithium pellets into Alcator C-Mod discharges. These transient modes, which typically persist about two energy confinement times, are characterized by a steep pressure gradient ({ell}{sub p} {le} a/5) in the inner third of the plasma, indicating the presence of an internal transport barrier. Inside this barrier, particle and energy diffusivities are greatly reduced, with ion thermal diffusivity dropping to near neoclassical values. Meanwhile, the global energy confinement time shows a 30% improvement over ITER89-P L-mode scaling. The addition of ICRF auxiliary heating shortly after the pellet injection leads to high fusion reactivity with neutron rates enhanced by an order of magnitude over L-mode discharges with similar input powers. A diagnostic system for measuring equilibrium current density profiles of tokamak plasmas, employing high speed lithium pellets, is also presented. Because ions are confined to move along field lines, imaging the Li{sup +} emission from the toroidally extended pellet ablation cloud gives the direction of the magnetic field. To convert from temporal to radial measurements, the 3-D trajectory of the pellet is determined using a stereoscopic tracking system. These measurements, along with external magnetic measurements, are used to solve the Grad-Shafranov equation for the magnetic equilibrium of the plasma. This diagnostic is used to determine the current density profile of PEP modes by injection of a second pellet during the period of good confinement. This measurement indicates that a region of reversed magnetic shear exists at the plasma core. This current density profile is consistent with TRANSP calculations for the bootstrap current created by the pressure gradient. MHD stability analysis indicates that these plasmas are near the n = {infinity} and the n = 1 marginal stability limits.

  14. Energy confinement studies of lower hybrid current driven discharges in the Alcator C tokamak

    International Nuclear Information System (INIS)

    The energy confinement properties of purely RF-driven plasmas on Alcator C are being investigated by experimental measurements of the bulk electron and ion temperature profiles, and by numerical modelling of the lower hybrid wave propagation and thermal energy transport. Power balance studies are performed on plasmas with parameters n-bar/sub e/ = 3-7 x 1013 cm-3, B = 7-11 T, I/sub p/ = 100-200 kA, and q(a)> or =8, and with RF powers up to 1 MW at 4.6 GHz. The temperature mesurements from RF-driven discharges are compared with those from similar ohmic discharges (identical current and density). The gross energy confinement time, defined by tau/sub E/03/2 (Σ∫n/sub j/T/sub j/ dV)/P/sub i//sub n/, is lower in the RF-driven discharges than in the ohmic ones by a factor of 1.5 to 4, depending on the plasma conditions and RF power. While tau/sub E/ in ohmic discharges increases with density and is independent of the toroidal field, the confinement time in the RF-driven discharges decreases with RF power, is independent of density in the range n-bar/sub e/ = 3-7 x 1013cm-3, and increases with the toroidal magnetic field. The confinement degrades slightly with increasing current in both RF-driven and ohmic discharges. The code used to simulate these results employs a lower hybrid ray tracing package, a Fokker-Planck code for the evolution of the fast electron tail, and enhanced thermal transport models for auxiliary-heated plasmas. In the code simulations, more than 80% of the injected RF power is absorbed by electron Landau damping in the inner half of the plasma column, the remainder being dissipated by collisions near the plasma edge

  15. Lower hybrid experiments at the 1 MW level on Alcator C: heating and current drive

    International Nuclear Information System (INIS)

    Lower hybrid current drive and heating experiments have been carried out on the Alcator C tokamak at power levels up to 1.15 MW in the density range 1.0 x 1013 less than or equal to anti n/sub e/(cm-3) less than or equal to 1.0 x 1014. By launching waves with 670, 900 or 1120 phasing of adjacent waveguides, maximum flat-top current drive efficiencies of eta = R(m) x n(1014cm-3)I(MA)/P(MW) = 0.12 at B = 10 tesla, and eta approx. = 0.08 at B = 8 tesla were obtained with molybdenum limiters. With graphite, or silicon-carbide coated graphite limiters the efficiencies were 30 to 40% lower. Current ramping experiments have also been carried out at densities up to anti n approx. = 6 x 1013cm-3. By phasing the adjacent waveguides at 1800, heating experiments were performed in the density range 8 x 1013 less than or equal to anti n(cm-3) less than or equal to 2 x 1014 in both hydrogen and deuterium plasmas. This range of densities corresponds to the electron Landau heating mode. Using molybdenum limiters, typical heating rates of the order of eta/sub H/ = delta Σ n/sub j/T/sub j//P/sub rf/ approx. = 10 eV/kW 1013cm-3 were obtained, whereas with the SiC coated graphite limiters heating rates up to eta/sub H/ approx. = 22 were achieved. Measurements of soft and hard x-rays indicate the presence of substantial electron tails in both the current drive and the electron heating regimes. A combined transport, ray-tracing and Fokker-Planck code is used to analyze and model both the heating and the current drive results

  16. Mode conversion electron heating in Alcator C-Mod: Theory and experiment

    Energy Technology Data Exchange (ETDEWEB)

    Bonoli, P. T. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Brambilla, M. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Nelson-Melby, E. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Phillips, C. K. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Porkolab, M. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Schilling, G. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Taylor, G. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Wukitch, S. J. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Boivin, R. L. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Boswell, C. J. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)] (and others)

    2000-05-01

    Localized electron heating [full width at half maximum of {delta}(r/a){approx_equal}0.2] by mode converted ion Bernstein waves (IBW) has been observed in the Alcator C-Mod tokamak [I. H. Hutchinson et al., Phys. Plasmas 1, 1511 (1994)]. These experiments were performed in D({sup 3}He) plasmas at high magnetic field (B{sub 0}=7.9 T), high-plasma density (n{sub e0}{>=}1.5x10{sup 20} m{sup -3}), and for 0.05{<=}n{sub He-3}/n{sub e}{<=}0.30. Electron heating profiles of the mode converted IBW were measured using a break in slope analysis of the electron temperature versus time in the presence of rf (radio frequency) modulation. The peak position of electron heating was found to be well-correlated with {sup 3}He concentration, in agreement with the predictions of cold plasma theory. Recently, a toroidal full-wave ion cyclotron range of frequencies (ICRF) code TORIC [M. Brambilla, Nucl. Fusion 38, 1805 (1998)] was modified to include the effects of IBW electron Landau damping at (k{sub (perpendicular} {sub sign)}{rho}{sub i}){sup 2}>>1, This model was used in combination with a 1D (one-dimensional) integral wave equation code METS [D. N. Smithe et al., Radio Frequency Power in Plasmas, AIP Conf. Proc. 403 (1997), p. 367] to analyze these experiments. Model predictions were found to be in qualitative and in some instances quantitative agreement with experimental measurements. A model for mode conversion current drive (MCCD) has also been developed which combines a toroidal full wave code with an adjoint evaluation of the ICRF current drive efficiency. Predictions for off-axis MCCD in C-Mod have been made using this model and will be described. (c) 2000 American Institute of Physics.

  17. Survey of ICRF heating experiments and enhanced performance modes in Alcator C-Mod

    Energy Technology Data Exchange (ETDEWEB)

    Takase, Y.; Boivin, R.L.; Bonoli, P.T. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Plasma Fusion Center] [and others

    1996-12-01

    Results of ICRF heating experiments in Alcator C-Mod during the November 1994 to June 1995 campaign are summarized. Efficient heating of high-density (nbar{sub e} ``

  18. Electron heating via mode converted ion Bernstein waves in the Alcator C-Mod tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Bonoli, P.T.; OShea, P.; Brambilla, M.; Golovato, S.N.; Hubbard, A.E.; Porkolab, M.; Takase, Y.; Boivin, R.L.; Bombarda, F.; Christensen, C.; Fiore, C.L.; Garnier, D.; Goetz, J.; Granetz, R.; Greenwald, M.; Horne, S.F.; Hutchinson, I.H.; Irby, J.; Jablonski, D.; LaBombard, B.; Lipschultz, B.; Marmar, E.; May, M.; Mazurenko, A.; McCracken, G.; Nachtrieb, R.; Niemczewski, A.; Ohkawa, H.; Pappas, D.A.; Reardon, J.; Rice, J.; Rost, C.; Schachter, J.; Snipes, J.A.; Stek, P.; Takase, K.; Terry, J.; Wang, Y.; Watterson, R.L.; Welch, B.; Wolfe, S.M. [Plasma Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    1997-05-01

    Highly localized direct electron heating [full width at half-maximum (FWHM){congruent}0.2a] via mode converted ion Bernstein waves has been observed in the Alcator C-Mod Tokamak [I. H. Hutchinson {ital et al.}, Phys. Plasmas {bold 1}, 1511 (1994)]. Electron heating at or near the plasma center (r/a{ge}0.3) has been observed in H({sup 3}He) discharges at B{sub 0}=(6.0{endash}6.5)T and n{sub e}(0){congruent}1.8{times}10{sup 20}m{sup {minus}3}. [Here, the minority ion species is indicated parenthetically.] Off-axis heating (r/a{ge}0.5) has also been observed in D({sup 3}He) plasmas at B{sub 0}=7.9T. The concentration of {sup 3}He in these experiments was in the range of n{sub 3{sub He}}/n{sub e}{congruent}(0.2{endash}0.3) and the locations of the mode conversion layer and electron heating peak could be controlled by changing the {sup 3}He concentration or toroidal magnetic field (B{sub 0}). The electron heating profiles were deduced using a rf modulation technique. Detailed comparisons with one-dimensional and toroidal full-wave models in the ion cyclotron range of frequencies have been carried out. One-dimensional full-wave code predictions were found to be in qualitative agreement with the experimental results. Toroidal full-wave calculations indicated the importance of volumetric and wave focusing effects in the interpretation of the experimental results. {copyright} {ital 1997 American Institute of Physics.}

  19. The design and performance of a twenty barrel hydrogen pellet injector for Alcator C-Mod

    Energy Technology Data Exchange (ETDEWEB)

    Urbahn, J.A.

    1994-05-01

    A twenty barrel hydrogen pellet injector has been designed, built and tested both in the laboratory and on the Alcator C-Mod Tokamak at MIT. The injector functions by firing pellets of frozen hydrogen or deuterium deep into the plasma discharge for the purpose of fueling the plasma, modifying the density profile and increasing the global energy confinement time. The design goals of the injector are: (1) Operational flexibility, (2) High reliability, (3) Remote operation with minimal maintenance. These requirements have lead to a single stage, pipe gun design with twenty barrels. Pellets are formed by in- situ condensation of the fuel gas, thus avoiding moving parts at cryogenic temperatures. The injector is the first to dispense with the need for cryogenic fluids and instead uses a closed cycle refrigerator to cool the thermal system components. The twenty barrels of the injector produce pellets of four different size groups and allow for a high degree of flexibility in fueling experiments. Operation of the injector is under PLC control allowing for remote operation, interlocked safety features and automated pellet manufacturing. The injector has been extrusively tested and shown to produce pellets reliably with velocities up to 1400 m/sec. During the period from September to November of 1993, the injector was successfully used to fire pellets into over fifty plasma discharges. Experimental results include data on the pellet penetration into the plasma using an advanced pellet tracking diagnostic with improved time and spatial response. Data from the tracker indicates pellet penetrations were between 30 and 86 percent of the plasma minor radius.

  20. Lower hybrid current drive experiments on the MIT Alcator C and Versator II tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Knowlton, S.; McDermott, S.; Porkolab, M.; Takase, Y.; Texter, S.; Bonoli, P.; Fiore, C.; McCool, S.; Mayberry, M.; Chen, K.I.

    1985-08-01

    Energy confinement studies in lower hybrid RF driven discharges at 4.6 GHz have been carried out on the Alcator C tokamak. The electron temperature profile is measured by a five point Thomson scattering system and the ion temperature by charge-exchange analysis. The energy content of the bulk plasma is found to be similar for RF-driven and ohmic discharges of identical current and density. In the parameter range anti n/sub e/ = 3 - 7 x 10/sup 13/ cm/sup -3/, B = 7 - 11 T, I/sub p/ = 100 - 200 kA, q (a) > 8, the RF power needed to sustain the discharge is significantly greater than the ohmic power required to maintain a similar plasma. The gross energy confinement time is lower in the RF-driven discharges than in the ohmic ones by a factor of 1.5 to 4, depending on plasma conditions. The frequency scaling of the density limit for current drive is reported from the Versator II tokamak. The steady-state current drive density limit of anti n/sub e/ = 6 x 10/sup 12/ cm/sup -3/ at 800 MHz. has been raised to a density of at least anti n/sub e/ = 1.0 x 10/sup 13/ cm/sup -3/ at the same toroidal field by operations at a frequency of 2.45 GHz. Superthermal electron effects during RF injection are observed up to a density of anti n/sub e/ = 2.5 x 10/sup 13/ cm/sup -3/.

  1. Study of parametric instabilities during the Alcator C lower hybrid wave heating experiments

    International Nuclear Information System (INIS)

    Parametric excitation of ion-cyclotron quasi-modes (ω/sub R/ approx. = nω/sub ci/) and ion-sound quasi-modes (ω/sub R/ approx. = k/sub parallel to/v/sub ti/) during lower hybrid wave heating of tokamak plasmas have been studied in detail. Such instabilities may significantly modify the incident wavenumber spectrum near the plasma edge. Convective losses for these instabilities are high if well-defined resonance cones exist, but they are significantly reduced if the resonance cones spread and fill the plasma volume (or some region of it). These instabilities preferentially excite lower hybrid waves with larger values of n/sub parallel to/ than themselves possess, and the new waves tend to be absorbed near the outer layers of the plasma. Parametric instabilities during lower hybrid heating of Alcator C plasmas have been investigated using rf probes (to study tilde phi and tilde n/sub i/) and CO2 scattering technique (to study tilde n/sub e/). At lower densities (anti n/sub e/ less than or equal to 0.5 x 1014cm-3) where waves observed in the plasma interior using CO2 scattering appear to be localized, parametric decay is very weak. Both ion-sound and ion-cyclotron parametric decay processes have been observed at higher densities (anti n greater than or equal to 1.5 x 1014cm-3) where waves appear to be unlocalized. Finally, at still higher densities (anti n /sub e/ greater than or equal to 2 x 104cm-3) pump depletion has been observed. Above these densities heating and current drive efficiencies are expected to degrade significantly

  2. Investigation of lower hybrid physics through power modulation experiments on Alcator C-Moda)

    Science.gov (United States)

    Schmidt, A.; Bonoli, P. T.; Meneghini, O.; Parker, R. R.; Porkolab, M.; Shiraiwa, S.; Wallace, G.; Wright, J. C.; Harvey, R. W.; Wilson, J. R.

    2011-05-01

    Lower hybrid current drive (LHCD) is an attractive tool for off-axis current profile control in magnetically confined tokamak plasmas and burning plasmas (ITER), because of its high current drive efficiency. The LHCD system on Alcator C-Mod operates at 4.6 GHz, with ~ 1 MW of coupled power, and can produce a wide range of launched parallel refractive index (n||) spectra. A 32 chord, perpendicularly viewing hard x-ray camera has been used to measure the spatial and energy distribution of fast electrons generated by lower hybrid (LH) waves. Square-wave modulation of LH power on a time scale much faster than the current relaxation time does not significantly alter the poloidal magnetic field inside the plasma and thus allows for realistic modeling and consistent plasma conditions for different n|| spectra. Inverted hard x-ray profiles show clear changes in LH-driven fast electron location with differing n||. Boxcar binning of hard x-rays during LH power modulation allows for ~ 1 ms time resolution which is sufficient to resolve the build-up, steady-state, and slowing-down phases of fast electrons. Ray-tracing/Fokker-Planck modeling in combination with a synthetic hard x-ray diagnostic shows quantitative agreement with the x-ray data for high n|| cases. The time histories of hollow x-ray profiles have been used to measure off-axis fast electron transport in the outer half of the plasma, which is found to be small on a slowing down time scale.

  3. Fluctuating zonal flows in the I-mode regime in Alcator C-Moda)

    Science.gov (United States)

    Cziegler, I.; Diamond, P. H.; Fedorczak, N.; Manz, P.; Tynan, G. R.; Xu, M.; Churchill, R. M.; Hubbard, A. E.; Lipschultz, B.; Sierchio, J. M.; Terry, J. L.; Theiler, C.

    2013-05-01

    Velocity fields and density fluctuations of edge turbulence are studied in I-mode [F. Ryter et al., Plasma Phys. Controlled Fusion 40, 725 (1998)] plasmas of the Alcator C-Mod [I. H. Hutchinson et al., Phys. Plasmas 1, 1511 (1994)] tokamak, which are characterized by a strong thermal transport barrier in the edge while providing little or no barrier to the transport of both bulk and impurity particles. Although previous work showed no clear geodesic-acoustic modes (GAM) on C-Mod, using a newly implemented, gas-puff-imaging based time-delay-estimate velocity inference algorithm, GAM are now shown to be ubiquitous in all I-mode discharges examined to date, with the time histories of the GAM and the I-mode specific [D. Whyte et al., Nucl. Fusion 50, 105005 (2010)] Weakly Coherent Mode (WCM, f = 100-300 kHz, Δf/f≈0.5, and kθ≈1.3 cm-1) closely following each other through the entire duration of the regime. Thus, the I-mode presents an example of a plasma state in which zero frequency zonal flows and GAM continuously coexist. Using two-field (density-velocity and radial-poloidal velocity) bispectral methods, the GAM are shown to be coupled to the WCM and to be responsible for its broad frequency structure. The effective nonlinear growth rate of the GAM is estimated, and its comparison to the collisional damping rate seems to suggest a new view on I-mode threshold physics.

  4. Impurity generation during intense lower hybrid heating experiments on the Alcator C tokamak

    Science.gov (United States)

    Marmar, E.; Foord, M.; Labombard, B.; Lipschultz, B.; Moreno, J.; Rice, J.; Terry, J.; Lloyd, B.; Porkolab, M.; Schuss, J.; Takase, Y.; Texter, S.; Fiore, C.; Gandy, R.; Granetz, R.; Greenwald, M.; Gwinn, D.; McCool, S.; Pappas, D.; Parker, R. R.; Pribyl, P.; Watterson, R.; Wolfe, S. M.

    1984-05-01

    Experiments are underway on the Alcator C tokamak with over 1 MW of RF power injected into the plasma at a frequency of 4.6 GHz to study both heating and current drive effects. During these studies, impurity generation from limiter structures has been observed. The RF induced impurity influx is a strongly nonlinear function of net injected power. For PRF < 500 kW, only small effects are seen. As PRF approaches 1 MW, however, sharp increases in impurity influxes and Zeff are observed. Three different limiter materials have been used during these studies: molybdenum, graphite, and silicon-carbide coated graphite. In each case, the materials of the limiter structure are seen to dominate the increased impurity influx. In a typical case, with P RF = 1.0 MW, overlinene = 1.3 × 10 14cm-3, and the SiC coated limiters, Zeff is seen to increase from 1.5 before the RF pulse to about 4 during the heating. At the same time, central Te increases from 2000 to 3000 eV and central Ti from 1200 to 1800 eV. Similar effects are seen in both H 2 and D 2 working gas discharges. The contribution to impurity generation of nonthermal electrons, which are produced by the RF, is under investigation. Changes in edge plasma temperature and density, as well as the possibility that the particle transport is affected by the RF, are also being examined. Results of the experiments with the three different limiter materials are compared, and contributions of impurity radiation to the overall power balance are estimated.

  5. Fast wave ion cyclotron resonance heating experiments on the Alcator C tokamak

    International Nuclear Information System (INIS)

    Minority regime fast wave ICRF heating experiments have been conducted on the Alcator C tokamak at rf power levels sufficient to produce significant changes in plasma properties, and in particular to investigate the scaling to high density of the rf heating efficiency. Up to 450 kW of rf power at frequency f = 180 MHz, was injected into plasmas composed of deuterium majority and hydrogen minority ion species at magnetic field B0 = 12 T, density 0.8 ≤ /bar n/sub e// ≤ 5 /times/ 1020 m-3, ion temperature T/sub D/(0) /approximately/ 1 keV, electron temperature T/sub e/(0) /approximately/ 1.5--2.5 keV, and minority concentration 0.25 /approx lt/ /eta/sub H// ≤ 8%. Deuterium heating ΔT/sub D/(0) = 400 eV was observed at /bar n/sub e// = 1 /times/ 1020 m-3, with smaller temperature increases at higher density. However, there was no significant change in electron temperature and the minority temperatures were insufficient to account for the launched rf power. Minority concentration scans indicated most efficient deuterium heating at the lowest possible concentration, in apparent contradiction with theory. Incremental heating /tau/sub inc// /equivalent to/ ΔW/ΔP up to 5 ms was independent of density, in spite of theoretical predictions of favorable density scaling of rf absorption and in stark contrast to Ohmic confinement times /tau/sub E// /equivalent to/ W/P. After accounting for mode conversion and minority losses due to toroidal field ripple, unconfined orbits, asymmetric drag, neoclassical and sawtooth transport, and charge-exchange, it was found that the losses as well as the net power deposition on deuterium do scale very favorably with density. Nevertheless, when the net rf and Ohmic powers deposited on deuterium are compared, they are found to be equally efficient at heating the deuterium. 139 refs

  6. Lithium pellet injection experiments on the Alcator C-Mod tokamak

    International Nuclear Information System (INIS)

    A pellet enhanced performance mode, showing significantly reduced core transport, is regularly obtained after the injection of deeply penetrating lithium pellets into Alcator C-Mod discharges. These transient modes, which typically persist about two energy confinement times, are characterized by a steep pressure gradient (ell p ≤ a/5) in the inner third of the plasma, indicating the presence of an internal transport barrier. Inside this barrier, particle and energy diffusivities are greatly reduced, with ion thermal diffusivity dropping to near neoclassical values. Meanwhile, the global energy confinement time shows a 30% improvement over ITER89-P L-mode scaling. The addition of ICRF auxiliary heating shortly after the pellet injection leads to high fusion reactivity with neutron rates enhanced by an order of magnitude over L-mode discharges with similar input powers. A diagnostic system for measuring equilibrium current density profiles of tokamak plasmas, employing high speed lithium pellets, is also presented. Because ions are confined to move along field lines, imaging the Li+ emission from the toroidally extended pellet ablation cloud gives the direction of the magnetic field. To convert from temporal to radial measurements, the 3-D trajectory of the pellet is determined using a stereoscopic tracking system. These measurements, along with external magnetic measurements, are used to solve the Grad-Shafranov equation for the magnetic equilibrium of the plasma. This diagnostic is used to determine the current density profile of PEP modes by injection of a second pellet during the period of good confinement. This measurement indicates that a region of reversed magnetic shear exists at the plasma core. This current density profile is consistent with TRANSP calculations for the bootstrap current created by the pressure gradient. MHD stability analysis indicates that these plasmas are near the n = ∞ and the n = 1 marginal stability limits

  7. Current Profile Measurements from Moderate to Strong Lower Hybrid Single-Pass Damping on Alcator C-Mod

    Science.gov (United States)

    Mumgaard, R. T.; Wallace, G. M.; Scott, S. D.; Shiraiwa, S.; Faust, I.; Parker, R. R.

    2015-11-01

    Lower Hybrid Current Drive (LHCD) is an effective tool to non-inductively drive up to 100% of the plasma current on Alcator C-Mod. Measurements with an upgraded MSE diagnostic show that the fast-electron current profile is broader than the Ohmic current profile but still located the plasma core in agreement with strongly centrally peaked fast electron bremsstrahlung (FEB) measurements. Scans in a regime of high current drive efficiency across a range of density, LHCD power, launched n||, and plasma current show the driven current profile, FEB profile shapes, and current drive efficiency are sensitive only to total plasma current. Simulations using ray-tracing Fokker Planck codes show that the rays make 1-3 bounces through the plasma edge to bridge the spectral gap. Although in agreement with the total current, the simulations qualitatively disagree with experiment regarding current and FEB profiles as well as sensitivity to power and density. Simulations at higher plasma temperature and current predict stronger single-pass damping and preliminary experiments show increased current drive efficiency. Experiments to determine if the profile discrepancies persist when the ray bounces play a reduced role are planned, including companion experiments in D and He resulting in different edge plasma conditions. This work was performed on the Alcator C-Mod tokamak, a DoE Office of Science user facility, and is supported by USDoE awards DE-FC02-99ER54512 and DE-AC02-09CH11466.

  8. Simulations of beam-emission spectroscopy on Alcator C-Mod (abstract)

    Energy Technology Data Exchange (ETDEWEB)

    Sampsell, M. B.; Bravenec, R. V.; Rowan, W. L.; Eisner, E. C.; Patterson, D. M.; Bretz, N. L.; Boivin, R. L.; Hubbard, A. E.; Irby, J. H.; Marmar, E. S. (and others)

    2001-01-01

    An eight-channel beam-emission-spectroscopy (BES)1 system has been installed on the Alcator C-Mod tokamak, intended for use with a diagnostic neutral hydrogen beam (DNB). Capable of localized measurements from the plasma edge to the plasma core, the BES diagnostic collects light from the first Balmer transition (H{sub {alpha}}) resultant from beam/plasma collisions. The H{sub {alpha}} line splits into several components whose central wavelengths depend on the viewing geometry, the magnetic field, and the beam energy. This is due to the Doppler shifts from viewing the beam off perpendicular, the different velocities of the three mass components of the beam (H, H{sub 2}, H{sub 3}), and the large motional Stark effect. Optimal signal-to-noise requires collecting these components while attenuating all other emission: primarily bremsstrahlung and D{sub {alpha}} radiation (from plasma D{sup 0}/e{sup -} collisions). Tunable bandpass filters are thus required. A BES simulation code has been developed that calculates the brightnesses (bremsstrahlung, D{sub {alpha}}, H{sub {alpha}}) versus wavelength using plasma profile data from the C-Mod MDSplus database,2 a computation of the beam penetration, the viewing and DNB geometries, and bandpass filter characteristics. The model was first used to estimate signal levels and choose the optimal BES bandpass filters; its ultimate purpose is to determine the shot-to-shot tuning requirements of the filters for different discharge conditions. Comparisons of measured and predicted background bremsstrahlung and D{sub {alpha}} brightnesses are presented, as are first measurements and calculations of the beam emission. The code is written in the IDL programming language3 utilizing the ''widget'' graphical user interface. Designed for geometrical and spectral flexibility, it can be modified to simulate other beam diagnostics such as motional-Stark-effect plasma current measurements and charge-exchange recombination

  9. Disruption Mitigation Experiments with Two Gas Jets on Alcator C-Mod

    International Nuclear Information System (INIS)

    Full text: Massive gas injection (MGI) disruption mitigation experiments have shown that this technique can quickly convert a large fraction of plasma thermal and magnetic energy into radiated power. To date, gas has been injected from a single spatial location, and bolometric measurements have shown that the resulting radiated power is often toroidally asymmetric, which could cause melting of beryllium first wall surfaces in ITER. Therefore, the ITER MGI system proposes multiple gas jets distributed around the torus. On Alcator C-Mod, a 2nd gas jet has been installed 154 degrees around the torus from the existing gas jet. The hardware components of both gas jets are nominally identical. A pair of AXUV photodiode arrays viewing the plasma midplane is used to measure the n = 1 component of the toroidal asymmetry, and a toroidally-distributed set of six individual detectors, each viewing a collimated slice of the plasma, provides toroidal resolution higher than n = 1 and is used to calculate the toroidal peaking factor (TPF) of the radiated power. Experiments have begun to characterise the effect of using two jets on the radiation TPF, varying the relative timing between the firing of the gas jets from shot-to-shot. It is observed that the TPF depends on the phase of the disruption. During the pre-TQ, when the gas is cooling the plasma edge, the TPF varies reproducibly with the relative gas jet timing. However, during the thermal quench (TQ) and current quench (CQ), when most of the plasma energy is radiated, the results are more complicated. At large positive delay times (i.e., jet 2 fires well after jet 1) the TPF is seen to be variable and often high, agreeing with earlier results using only this jet. However, at large negative delay times (jet 2 fires well before jet 1), the TPF is significantly lower and more reproducible. This may indicate that slight differences in hardware and/or geometry between the two gas jet systems are important. The growth of n = 1 MHD

  10. Structure and motion of edge turbulence in the National Spherical Torus Experiment and Alcator C-Moda)

    Science.gov (United States)

    Zweben, S. J.; Maqueda, R. J.; Terry, J. L.; Munsat, T.; Myra, J. R.; D'Ippolito, D.; Russell, D. A.; Krommes, J. A.; LeBlanc, B.; Stoltzfus-Dueck, T.; Stotler, D. P.; Williams, K. M.; Bush, C. E.; Maingi, R.; Grulke, O.; Sabbagh, S. A.; White, A. E.

    2006-05-01

    In this paper we compare the structure and motion of edge turbulence observed in L-mode vs. H-mode plasmas in the National Spherical Torus Experiment (NSTX) [M. Ono, M. G. Bell, R. E. Bell et al., Plasma Phys. Controlled Fusion 45, A335 (2003)]. The radial and poloidal correlation lengths are not significantly different between the L-mode and the H-mode in the cases examined. The poloidal velocity fluctuations are lower and the radial profiles of the poloidal turbulence velocity are somewhat flatter in the H-mode compared with the L-mode plasmas. These results are compared with similar measurements Alcator C-Mod [E. Marmar, B. Bai, R. L. Boivin et al., Nucl. Fusion 43, 1610 (2003)], and with theoretical models.

  11. Phase contrast imaging measurements of reversed shear Alfvén eigenmodes during sawteeth in Alcator C-Moda)

    Science.gov (United States)

    Edlund, E. M.; Porkolab, M.; Kramer, G. J.; Lin, L.; Lin, Y.; Wukitch, S. J.

    2009-05-01

    Reversed shear Alfvén eigenmodes (RSAEs) have been observed with the phase contrast imaging diagnostic and Mirnov coils during the sawtooth cycle in Alcator C-mod [M. Greenwald et al., Nucl. Fusion 45, S109 (2005)] plasmas with minority ion-cyclotron resonance heating. Both down-chirping RSAEs and up-chirping RSAEs have been observed during the sawtooth cycle. Experimental measurements of the spatial structure of the RSAEs are compared to theoretical models based on the code NOVA [C. Z. Cheng and M. S. Chance, J. Comput. Phys. 71, 124 (1987)] and used to derive constraints on the q profile. It is shown that the observed RSAEs can be understood by assuming a reversed shear q profile (up chirping) or a q profile with a local maximum (down chirping) with q ≈1.

  12. Modification of ordinary-mode reflectometry system to detect lower-hybrid waves in Alcator C-Moda)

    Science.gov (United States)

    Baek, S. G.; Shiraiwa, S.; Parker, R. R.; Dominguez, A.; Kramer, G. J.; Marmar, E. S.

    2012-10-01

    Backscattering experiments to detect lower-hybrid (LH) waves have been performed in Alcator C-Mod, using the two modified channels (60 GHz and 75 GHz) of an ordinary-mode reflectometry system with newly developed spectral recorders that can continuously monitor spectral power at a target frequency. The change in the baseline of the spectral recorder during the LH wave injection is highly correlated to the strength of the X-mode non-thermal electron cyclotron emission. In high density plasmas where an anomalous drop in the lower hybrid current drive efficiency is observed, the observed backscattered signals are expected to be generated near the last closed flux surface, demonstrating the presence of LH waves within the plasma. This experimental technique can be useful in identifying spatially localized LH electric fields in the periphery of high-density plasmas.

  13. EMC3-EIRENE modeling of toroidally-localized divertor gas injection experiments on Alcator C-Mod

    Energy Technology Data Exchange (ETDEWEB)

    Lore, J.D., E-mail: lorejd@ornl.gov [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Reinke, M.L. [York Plasma Institute, Department of Physics, University of York, Heslington, York YO10 5DD (United Kingdom); LaBombard, B. [Plasma Science and Fusion Center, MIT, Cambridge, MA 02139 (United States); Lipschultz, B. [York Plasma Institute, Department of Physics, University of York, Heslington, York YO10 5DD (United Kingdom); Churchill, R.M. [Plasma Science and Fusion Center, MIT, Cambridge, MA 02139 (United States); Pitts, R.A. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Feng, Y. [Max Planck Institute for Plasma Physics, Greifswald (Germany)

    2015-08-15

    Experiments on Alcator C-Mod with toroidally and poloidally localized divertor nitrogen injection have been modeled using the three-dimensional edge transport code EMC3-EIRENE to elucidate the mechanisms driving measured toroidal asymmetries. In these experiments five toroidally distributed gas injectors in the private flux region were sequentially activated in separate discharges resulting in clear evidence of toroidal asymmetries in radiated power and nitrogen line emission as well as a ∼50% toroidal modulation in electron pressure at the divertor target. The pressure modulation is qualitatively reproduced by the modeling, with the simulation yielding a toroidal asymmetry in the heat flow to the outer strike point. Toroidal variation in impurity line emission is qualitatively matched in the scrape-off layer above the strike point, however kinetic corrections and cross-field drifts are likely required to quantitatively reproduce impurity behavior in the private flux region and electron temperatures and densities directly in front of the target.

  14. High resolution measurements of neutral density and ionization rate in the main chamber of the Alcator C-Mod tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Boivin, R.L. E-mail: boivin@psfc.mit.edu; Goetz, J.; Hubbard, A.; Hughes, J.W.; Irby, J.; LaBombard, B.; Marmar, E.; Mossessian, D.; Terry, J.L

    2001-03-01

    Recent theoretical and experimental work has focused on the importance of neutrals in the edge dynamics of Alcator C-Mod plasmas. Two new high resolution detectors have been installed on the Alcator C-Mod tokamak to measure the neutral density and ionization rate near the edge of the discharge in the main chamber. The detectors consist of a 20 channel photodiode array which views the plasma tangentially 12.5 cm below the outer midplane, and 10 cm above the inner midplane, with a nominal radial resolution of 2 and 3 mm, respectively. The spectral bandwidth is limited by a filter with a very narrow band around the neutral deuterium Lyman alpha wavelength (1215 Angstrom). The local emissivity is then obtained via a standard Abel inversion of the absolutely calibrated brightness profile. Employing well-known branching ratios, and using measured local electron density and temperature, we therefore, infer the neutral density and ionization rate with similar radial resolution. We have observed that both Lyman alpha emissivity and ionization rate are usually peaked near the separatrix with a full width, half-maximum between 1 and 2 cm. The neutral density was found to drop rapidly with decreasing minor radius, from 2-3x10{sup 17}/m{sup 3} (5-10 mm outside the separatrix) to 1-2x10{sup 16}/m{sup 3} (5-10 mm inside the separatrix) for a line averaged density of 2.0x10{sup 20}/m{sup 3}. Variations in ionization rate and neutral density from low to high confinement mode (L and H mode) are also discussed.

  15. Study and optimization of boronization in Alcator C-Mod using the Surface Science Station (S{sup 3})

    Energy Technology Data Exchange (ETDEWEB)

    Ochoukov, Roman, E-mail: ochoukov@psfc.mit.edu [Plasma Science and Fusion Center MIT, NW17, 175 Albany Street, Cambridge, MA 02139 (United States); Whyte, Dennis; Lipschultz, Bruce; LaBombard, Brian [Plasma Science and Fusion Center MIT, NW17, 175 Albany Street, Cambridge, MA 02139 (United States); Gierse, Niels [Institute of Energy and Climate Research - Plasma Physics, Forschungszentrum Juelich GmbH, Association EURATOM-FZJ, Partner in the Trilateral Euregio Cluster, Juelich (Germany); Physikalisches Institut, Universitaet zu Koeln, D-50937 Cologne (Germany); Harrison, Soren [Fusion Research Technologies, 519 Somerville Avenue 243, Somerville, MA 02143 (United States)

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer Boron deposition profiles measured on Alcator C-Mod during boronization. Black-Right-Pointing-Pointer Boron deposition profile is consistent with ionic deposition. Black-Right-Pointing-Pointer Monte Carlo simulation of boron deposition agrees with experiment assuming warm ({approx}1-10 eV) boron{sup +1} ions. - Abstract: A Surface Science Station (S{sup 3}) on the Alcator C-Mod tokamak is used to study and optimize the location and rate of boron film deposition in situ during electron cyclotron (EC) discharge plasmas using 2.45 GHz radio-frequency (RF) heating and a mixture of helium and diborane (B{sub 2}D{sub 6}) gasses. The radial profile of boron deposition is measured with a pair of quartz microbalances (QMB) on S{sup 3}, the faces of which can be rotated 360 Degree-Sign including orientations parallel and perpendicular to the toroidal magnetic field B{sub T} {approx}0.1 T. The plasma electron density is measured with a Langmuir probe, also on S{sup 3} in the vicinity of the QMBs, and typical values are {approx}1 Multiplication-Sign 10{sup 16} m{sup -3}. A maximum boron deposition rate of 0.82 {mu}g/cm{sup 2}/min is obtained, which corresponds to 3.5 nm/min if the film density is that of solid boron. These deposition rates are sufficient for boron film applications between tokamak discharges. However the deposition does not peak at the EC resonance as previously assumed. Rather, deposition peaks near the upper hybrid (UH) resonance, {approx}5 cm outboard of the EC resonance. This has implications for RF absorption, with the RF waves being no longer damped on the electrons at the EC resonance. The previously inferred radial locations of critical erosion zones in Alcator C-Mod also need to be re-evaluated. The boron deposition profile versus major radius follows the ion flux/density profile, implying that the boron deposition is primarily ionic. The application of a vertical magnetic field (B{sub V} {approx}0.01 T) was

  16. Study of electron temperature evolution during sawtoothing and pellet injection using thermal electron cyclotron emission in the Alcator C tokamak

    International Nuclear Information System (INIS)

    A study of the electron temperature evolution has been performed using thermal electron cyclotron emission. A six channel far infrared polychromator was used to monitor the radiation eminating from six radial locations. The time resolution was <3 μs. Three events were studied, the sawtooth disruption, propagation of the sawtooth generated heatpulse and the electron temperature response to pellet injection. The sawtooth disruption in Alcator takes place in 20 to 50 μs, the energy mixing radius is approx. 8 cm or a/2. It is shown that this is inconsistent with single resonant surface Kadomtsev reconnection. Various forms of scalings for the sawtooth period and amplitude were compared. The electron heatpulse propagation has been used to estimate chi e(the electron thermal diffusivity). The fast temperature relaxation observed during pellet injection has also been studied. Electron temperature profile reconstructions have shown that the profile shape can recover to its pre-injection form in a time scale of 200 μs to 3 ms depending on pellet size

  17. Measurements of relativistic emission from runaway electrons in Alcator C-Mod: spectrum, polarization, and spatial structure

    Science.gov (United States)

    Granetz, Robert; Mumgaard, Robert

    2014-10-01

    At low densities, runaway electrons (RE's) can be generated during the flattop of Alcator C-Mod discharges with highly relativistic energies, γ >> 1 , allowing careful study under steady conditions. These RE's emit light in a narrow forward-peaked cone which is detected with a number of diagnostics, including spectrometers, a video imaging camera, and polarimetry (using the MSE system), in addition to the standard hard x-ray detectors. These measurements of the relativistic emission can provide information about the RE energy distribution, pitch angle distribution, and spatial distribution. Unlike most other tokamaks, C-Mod's high magnetic field shifts the peak of the continuum emission into the visible, due to the smaller gyroradius and higher gyro-frequency, allowing for excellent spectral coverage with standard spectrometers, and thus detailed comparison to theoretical predictions of synchrotron and bremsstrahlung spectra. Additionally, camera images occasionally show highly structured formations. Profiles of the polarization fraction and polarization angle show radial structure, including a jump of 90° outboard of the magnetic axis, in qualitative agreement with recent theoretical calculations for relativistic electrons in a tokamak field. This work is supported by the U.S. Department of Energy.

  18. Upgraded PMI diagnostic capabilities using Accelerator-based In-situ Materials Surveillance (AIMS) on Alcator C-Mod

    Science.gov (United States)

    Kesler, Leigh; Barnard, Harold; Hartwig, Zachary; Sorbom, Brandon; Lanza, Richard; Terry, David; Vieira, Rui; Whyte, Dennis

    2014-10-01

    The AIMS diagnostic was developed to rapidly and non-invasively characterize in-situ plasma material interactions (PMI) in a tokamak. Recent improvements are described which significantly expand this measurement capability on Alcator C-Mod. The detection time at each wall location is reduced from about 10 min to 30 s, via improved hardware and detection geometry. Detectors are in an augmented re-entrant tube to maximize the solid angle between detectors and diagnostic locations. Spatial range is expanded by using beam dynamics simulation to design upgraded B-field power supplies to provide maximal poloidal access, including a ~20° toroidal range in the divertor. Measurement accuracy is improved with angular and energy resolved cross section measurements obtained using a separate 0.9 MeV deuteron ion accelerator. Future improvements include the installation of recessed scintillator tiles as beam targets for calibration of the diagnostic. Additionally, implanted depth marker tiles will enable AIMS to observe the in-situ erosion and deposition of high-Z plasma-facing materials. This work is supported by U.S. DOE Grant No. DE-FG02-94ER54235 and Cooperative Agreement No. DE-FC02-99ER54512.

  19. H-mode pedestal and threshold studies over an expanded operating space on Alcator C-Moda)

    Science.gov (United States)

    Hubbard, A. E.; Hughes, J. W.; Bespamyatnov, I. O.; Biewer, T.; Cziegler, I.; LaBombard, B.; Lin, Y.; McDermott, R.; Rice, J. E.; Rowan, W. L.; Snipes, J. A.; Terry, J. L.; Wolfe, S. M.; Wukitch, S.

    2007-05-01

    This paper reports on studies of the edge transport barrier and transition threshold of the high confinement (H) mode of operation on the Alcator C-Mod tokamak [I. H. Hutchinson et al., Phys. Plasmas 1, 1511 (1994)], over a wide range of toroidal field (2.6-7.86T) and plasma current (0.4-1.7MA). The H-mode power threshold and edge temperature at the transition increase with field. Barrier widths, pressure limits, and confinement are nearly independent of field at constant current, but the operational space at high B shifts toward higher temperature and lower density and collisionality. Experiments with reversed field and current show that scrape-off-layer flows in the high-field side depend primarily on configuration. In configurations with the B ×∇B drift away from the active X-point, these flows lead to more countercurrent core rotation, which apparently contributes to higher H-mode thresholds. In the unfavorable case, edge temperature thresholds are higher, and slow evolution of profiles indicates a reduction in thermal transport prior to the transition in particle confinement. Pedestal temperatures in this case are also higher than in the favorable configuration. Both high-field and reversed-field results suggest that parameters at the L-H transition are influencing the evolution and parameters of the H-mode pedestal.

  20. Lower Hybrid Wave Induced SOL Emissivity Variation at High Density on the Alcator C-Mod Tokamak

    International Nuclear Information System (INIS)

    Lower Hybrid Current Drive (LHCD) in the Alcator C-Mod tokamak provides current profile control for the generation of Advanced Tokamak (AT) plasmas. Non-thermal electron bremsstrahlung emission decreases dramatically at n-bare>1·1020[m-3] for diverted discharges, indicating low current drive efficiency. It is suggested that Scrape-Off-Layer (SOL) collisional absorption of LH waves is the cause for the absence of non-thermal electrons at high density. VUV and visible spectroscopy in the SOL provide direct information on collision excitation processes. Deuterium Balmer-, Lyman- and He-I transition emission measurements were used for initial characterization of SOL electron-neutral collisional absorption. Data from Helium and Deuterium LHCD discharges were characterized by an overall increase in the emissivity as well as an outward radial shift in the emissivity profile with increasing plasma density and applied LHCD power. High-temperature, high-field (Te = 5keV,Bt = 8T) helium discharges at high density display increased non-thermal signatures as well as reduced SOL emissivity. Variations in emissivity due to LHCD were seen in SOL regions not magnetically connected to the LH Launcher, indicating global SOL effects due to LHCD.

  1. A Spatially Resolving X-ray Crystal Spectrometer for Measurement of Ion-temperature and Rotation-velocity Profiles on the AlcatorC-Mod Tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Hill, K. W.; Bitter, M. L.; Scott, S. D.; Ince-Cushman, A.; Reinke, M.; Rice, J. E.; Beiersdorfer, P.; Gu, M. F.; Lee, S. G.; Broennimann, C. H.; Eikenberry, E. F.

    2009-03-24

    A new spatially resolving x-ray crystal spectrometer capable of measuring continuous spatial profiles of high resolution spectra (λ/dλ > 6000) of He-like and H-like Ar Kα lines with good spatial (~1 cm) and temporal (~10 ms) resolutions has been installed on the Alcator C-Mod tokamak. Two spherically bent crystals image the spectra onto four two-dimensional Pilatus II pixel detectors. Tomographic inversion enables inference of local line emissivity, ion temperature (Ti), and toroidal plasma rotation velocity (vφ) from the line Doppler widths and shifts. The data analysis techniqu

  2. Edge energy transport barrier and turbulence in the I-mode regime on Alcator C-Moda)

    Science.gov (United States)

    Hubbard, A. E.; Whyte, D. G.; Churchill, R. M.; Cziegler, I.; Dominguez, A.; Golfinopoulos, T.; Hughes, J. W.; Rice, J. E.; Bespamyatnov, I.; Greenwald, M. J.; Howard, N.; Lipschultz, B.; Marmar, E. S.; Reinke, M. L.; Rowan, W. L.; Terry, J. L.

    2011-05-01

    We report extended studies of the I-mode regime [Whyte et al., Nucl. Fusion 50, 105005 (2010)] obtained in the Alcator C-Mod tokamak [Marmar et al., Fusion Sci. Technol. 51(3), 3261 (2007)]. This regime, usually accessed with unfavorable ion B × ∇B drift, features an edge thermal transport barrier without a strong particle transport barrier. Steady I-modes have now been obtained with favorable B × ∇B drift, by using specific plasma shapes, as well as with unfavorable drift over a wider range of shapes and plasma parameters. With favorable drift, power thresholds are close to the standard scaling for L-H transitions, while with unfavorable drift they are ˜ 1.5-3 times higher, increasing with Ip. Global energy confinement in both drift configurations is comparable to H-mode scalings, while density profiles and impurity confinement are close to those in L-mode. Transport analysis of the edge region shows a decrease in edge χeff, by typically a factor of 3, between L- and I-mode. The decrease correlates with a drop in mid-frequency fluctuations (f ˜ 50-150 kHz) observed on both density and magnetics diagnostics. Edge fluctuations at higher frequencies often increase above L-mode levels, peaking at f ˜ 250 kHz. This weakly coherent mode is clearest and has narrowest width (Δf/f ˜ 0.45) at low q95 and high Tped, up to 1 keV. The Er well in I-mode is intermediate between L- and H-mode and is dominated by the diamagnetic contribution in the impurity radial force balance, without the Vpol shear typical of H-modes.

  3. Observation of ion cyclotron range of frequencies mode conversion plasma flow drive on Alcator C-Moda)

    Science.gov (United States)

    Lin, Y.; Rice, J. E.; Wukitch, S. J.; Greenwald, M. J.; Hubbard, A. E.; Ince-Cushman, A.; Lin, L.; Marmar, E. S.; Porkolab, M.; Reinke, M. L.; Tsujii, N.; Wright, J. C.; Alcator C-Mod Team

    2009-05-01

    At modest H3e levels (n3He/ne˜8%-12%), in relatively low density D(H3e) plasmas, n¯e≤1.3×1020 m-3, heated with 50 MHz rf power at Bt0˜5.1 T, strong (up to 90 km/s) toroidal rotation (Vϕ) in the cocurrent direction has been observed by high-resolution x-ray spectroscopy on Alcator C-Mod. The change in central Vϕ scales with the applied rf power (≤30 km s-1 MW-1), and is generally at least a factor of 2 higher than the empirically determined intrinsic plasma rotation scaling. The rotation in the inner plasma (r /a≤0.3) responds to the rf power more quickly than that of the outer region (r /a≥0.7), and the rotation profile is broadly peaked for r /a≤0.5. Localized poloidal rotation (0.3≤r/a≤0.6) in the ion diamagnetic drift direction (˜2 km/s at 3 MW) is also observed, and similarly increases with rf power. Changing the toroidal phase of the antenna does not affect the rotation direction, and it only weakly affects the rotation magnitude. The mode converted ion cyclotron wave (MC ICW) has been detected by a phase contrast imaging system and the MC process is confirmed by two-dimensional full wave TORIC simulations. The simulations also show that the MC ICW is strongly damped on H3e ions in the vicinity of the MC layer, approximately on the same flux surfaces where the rf driven flow is observed. The flow shear in our experiment is marginally sufficient for plasma confinement enhancement based on the comparison of the E ×B shearing rate and gyrokinetic linear stability analysis.

  4. Local gas injection as a scrape-off layer diagnostic on the Alcator C-Mod tokamak

    International Nuclear Information System (INIS)

    A capillary puffing array has been installed on Alcator C-Mod which allows localized introduction of gaseous species in the scrape-off layer. This system has been utilized in experiments to elucidate both global and local properties of edge transport. Deuterium fueling and recycling impurity screening are observed to be characterized by non-dimensional screening efficiencies which are independent of the location of introduction. In contrast, the behavior of non-recycling impurities is seen to be characterized by a screening time which is dependent on puff location. The work of this thesis has focused on the use of the capillary array with a camera system which can view impurity line emission plumes formed in the region of an injection location. The ionic plumes observed extend along the magnetic field line with a comet-like asymmetry, indicative of background plasma ion flow. The flow is observed to be towards the nearest strike-point, independent of x-point location, magnetic field direction, and other plasma parameters. While the axes of the plumes are generally along the field line, deviations are seen which indicate cross-field ion drifts. A quasi-two dimensional fluid model has been constructed to use the plume shapes of the first charge state impurity ions to extract information about the local background plasma, specifically the temperature, parallel flow velocity, and radial electric field. Through comparisons of model results with those of a three dimensional Monte Carlo code, and comparisons of plume extracted parameters with scanning probe measurements, the efficacy of the model is demonstrated. Plume analysis not only leads to understandings of local edge impurity transport, but also presents a novel diagnostic technique

  5. Local gas injection as a scrape-off layer diagnostic on the Alcator C-Mod tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Jablonski, D.F.

    1996-05-01

    A capillary puffing array has been installed on Alcator C-Mod which allows localized introduction of gaseous species in the scrape-off layer. This system has been utilized in experiments to elucidate both global and local properties of edge transport. Deuterium fueling and recycling impurity screening are observed to be characterized by non-dimensional screening efficiencies which are independent of the location of introduction. In contrast, the behavior of non-recycling impurities is seen to be characterized by a screening time which is dependent on puff location. The work of this thesis has focused on the use of the capillary array with a camera system which can view impurity line emission plumes formed in the region of an injection location. The ionic plumes observed extend along the magnetic field line with a comet-like asymmetry, indicative of background plasma ion flow. The flow is observed to be towards the nearest strike-point, independent of x-point location, magnetic field direction, and other plasma parameters. While the axes of the plumes are generally along the field line, deviations are seen which indicate cross-field ion drifts. A quasi-two dimensional fluid model has been constructed to use the plume shapes of the first charge state impurity ions to extract information about the local background plasma, specifically the temperature, parallel flow velocity, and radial electric field. Through comparisons of model results with those of a three dimensional Monte Carlo code, and comparisons of plume extracted parameters with scanning probe measurements, the efficacy of the model is demonstrated. Plume analysis not only leads to understandings of local edge impurity transport, but also presents a novel diagnostic technique.

  6. Plasma X-ray emission in the 20-500 keV range during lower hybrid current drive on Alcator

    International Nuclear Information System (INIS)

    An array of eight 1'' x 3'' NaI scintillators has been used to collect plasma hard x-ray spectra (E/sub γ/>20 keV) emitted perpendicular to the magnetic axis during lower hybrid current drive on Alcator. The spectra exhibit a tail extending out to at least 300 keV and the profiles are generally peaked. These results show that the slope of the x-ray spectra increases with increasing plasma radius. Equivalently, the emission profiles tend to broaden with increasing photon energy. Also, the x-ray spectra slope increases at each radial location as the relative phasing of adjacent waveguides in the grill antenna is decreased. Preliminary results also suggest that the x-ray spectra tend to flatten and that the emission profiles tend to peak up with decreasing plasma density or increasing magnetic field. In addition, the initial results of an array for measuring the high energy x-ray emission from Alcator as a function of the emission angle relative to the magnetic axis are presented

  7. Multi-device studies of pedestal physics and confinement in the I-mode regime

    Science.gov (United States)

    Hubbard, A. E.; Osborne, T.; Ryter, F.; Austin, M.; Barrera Orte, L.; Churchill, R. M.; Cziegler, I.; Fenstermacher, M.; Fischer, R.; Gerhardt, S.; Groebner, R.; Gohil, P.; Happel, T.; Hughes, J. W.; Loarte, A.; Maingi, R.; Manz, P.; Marinoni, A.; Marmar, E. S.; McDermott, R. M.; McKee, G.; Rhodes, T. L.; Rice, J. E.; Schmitz, L.; Theiler, C.; Viezzer, E.; Walk, J. R.; White, A.; Whyte, D.; Wolfe, S.; Wolfrum, E.; Yan, Z.; Alcator C-Mod, the; Upgrade, ASDEX; DIII-D Teams

    2016-08-01

    This paper describes joint ITPA studies of the I-mode regime, which features an edge thermal barrier together with L-mode-like particle and impurity transport and no edge localized modes (ELMs). The regime has been demonstrated on the Alcator C-Mod, ASDEX Upgrade and DIII-D tokamaks, over a wide range of device parameters and pedestal conditions. Dimensionless parameters at the pedestal show overlap across devices and extend to low collisionality. When they are matched, pedestal temperature profiles are also similar. Pedestals are stable to peeling-ballooning modes, consistent with lack of ELMs. Access to I-mode is independent of heating method (neutral beam injection, ion cyclotron and/or electron cyclotron resonance heating). Normalized energy confinement H 98,y2  ⩾  1 has been achieved for a range of 3  ⩽  q 95  ⩽  4.9 and scales favourably with power. Changes in turbulence in the pedestal region accompany the transition from L-mode to I-mode. The L-I threshold increases with plasma density and current, and with device size, but has a weak dependence on toroidal magnetic field B T. The upper limit of power for I-modes, which is set by I-H transitions, increases with B T and the power range is largest on Alcator C-Mod at B  >  5 T. Issues for extrapolation to ITER and other future fusion devices are discussed.

  8. In-situ erosion and deposition measurements of plasma-facing surfaces in Alcator C-Mod

    Science.gov (United States)

    Barnard, Harold S.

    2014-10-01

    The Accelerator Based In-situ Materials Surveillance (AIMS) diagnostic was recently developed to demonstrate the novel application of ion beam analysis (IBA) to in-vessel studies of plasma materials interactions in Alcator C-Mod. The AIMS diagnostic injects a 900 keV deuterium ion beam into the tokamak's vacuum vessel between plasma discharges while magnetic fields are used to steer the ion beam to plasma facing component (PFC) surfaces. Spectroscopic analysis of neutrons and gamma rays from the induced nuclear reactions provides a quantitative, spatially resolved map of the PFC surface composition that includes boron (B) and deuterium (D) content. Since AIMS is sensitive to low-Z elements and C-Mod regularly boronizes PFCs, the evolution of B and D on PFCs can be used to directly study erosion, deposition, and fuel retention in response to plasma operations and wall conditioning processes. AIMS analysis of 18 lower single null I-mode discharges show a net boron deposition rate of 6 +/- 2 nm/s on the inner wall while subsequent inner wall limited discharges and a disruption did not show significant changes in B. Measurements of D content showed relative changes of >2.5 following a similar trend. This suggests high D retention rates and net B deposition rates of ~18 cm/year of plasma exposure are possible and depend strongly on the plasma conditions. Ex-situ IBA was also performed on the same PFCs after removal from C-Mod, successfully validating the AIMS technique. These IBA measurements also show that the B content on the inner wall varied toroidally and poloidally from 0 to 3000 nm, demonstrating the importance of the spatial resolution provided by AIMS and the sensitivity of PFCs to B-field alignment. AIMS upgrades are underway for operation in 2014 and we anticipate new measurements correlating the evolution of PFC surfaces to plasma configuration, RF heating, and current drive scenarios. This work is supported by U.S. DOE Grant No. DE-FG02-94ER54235 and

  9. Pedestal Stability and Transport on the Alcator C-Mod Tokamak: Experiments in Support of Developing Predictive Capability

    International Nuclear Information System (INIS)

    Full text: New experimental data on the Alcator C-Mod tokamak are used to benchmark predictive modeling of the edge pedestal in various high-confinement regimes, contributing to a greater confidence in projection of pedestal height and width in ITER and reactors. Measurements in conventional Type-I ELMy H-mode have been used to test the theory of peeling-ballooning (PB) stability and pedestal structure predictions from the EPED model, which extends these theoretical comparisons to the highest pressure pedestals of any existing tokamak. Calculations with the ELITE code confirm that C-Mod ELMy H-modes operate near stability limits for ideal PB modes. Experimental C-Mod studies have provided supporting evidence for pedestal width scaling as the square root of poloidal beta at the pedestal top. This is the dependence that would be expected from theory if KBMs were responsible for limiting the pedestal width. The EPED model has been tested across an extended data on C-Mod, reproducing pedestal height and width reasonably well, and extending the tested range of EPED to within a factor of 3 of the absolute pedestal pressure targeted for ITER. In addition, C-Mod offers access to two regimes, enhanced D-alpha (EDA) H-mode and I- mode, that have high pedestals but in which large ELM activity is naturally suppressed and, instead, particle and impurity transport are regulated continuously. Significant progress has been made in both measuring and modeling pedestal fluctuations, transport and stability in these regimes. Pedestals of EDA H-mode and I-mode discharges are found to be ideal MHD stable, consistent with the general absence of ELM activity. Like ELITE, the BOUT++ code finds the EDA pedestal to be stable to ideal modes. However, it does identify finite growth rates for edge modes when realistic values of resistivity and diamagnetism are included. The result is consistent with the interpretation of the quasi-coherent mode (QCM), which is omnipresent in the EDA pedestal

  10. Evaluation of Optimized ICRF and LHRF Antennas in Alcator C-Mod

    International Nuclear Information System (INIS)

    Full text: Ion cyclotron range of frequency heating (ICRF) and lower hybrid range of frequency current drive (LHCD) are expected to be key heating and current drive actuators for future fusion reactors and devices. However, impurity contamination associated with ICRF antenna operation remains a major challenge, particularly in devices with metallic plasma facing components. For LHCD, maximizing coupled power to the plasma remains a challenge, particularly to maintain low reflection coefficient over range of plasma conditions. Here, we report on an experimental investigation to test whether a field aligned (FA) ICRF antenna can reduce the impurity contamination and SOL modification associated with antenna operation. We also report on results from a new limiter for the LH coupler designed to reduce reflection coefficients across a wider range of plasma conditions. The unique feature of the so-called FA-antenna is that the current straps and antenna box structure are perpendicular to the total magnetic field. This alignment allows integrated E|| (electric field along a magnetic field line) to be minimized through symmetry. Using finite element method and a cold plasma model, the FA-antenna has been found to have lower integrated E|| relative to the previous antenna geometry. Initial results indicate that the impurity contamination associated with the FA-antenna is lower relative to our standard ICRF antennas. Configured as a 2-strap antenna, the antenna has lower core impurity contamination and lower impurity source at the antenna at high power density (∼ 15 MW/m2). An array of core and boundary plasma diagnostics are presently being used to characterize the impurity behavior and impact on the SOL transport and SOL density profiles; the latest results will be presented. For LHCD, reflection coefficients are very sensitive to the local density and its profile in front of the LHCD coupler. Previously the local LH coupler protection limiter was fixed to the outer wall

  11. Photovoltaic device

    Science.gov (United States)

    Reese, Jason A.; Keenihan, James R.; Gaston, Ryan S.; Kauffmann, Keith L.; Langmaid, Joseph A.; Lopez, Leonardo C.; Maak, Kevin D.; Mills, Michael E.; Ramesh, Narayan; Teli, Samar R.

    2015-06-02

    The present invention is premised upon an improved photovoltaic device ("PV device"), more particularly to an improved photovoltaic device with a multilayered photovoltaic cell assembly and a body portion joined at an interface region and including an intermediate layer, at least one interconnecting structural member, relieving feature, unique component geometry, or any combination thereof.

  12. Concentration device

    DEFF Research Database (Denmark)

    2013-01-01

    A concentration device (2) for filter filtration concentration of particles (4) from a volume of a fluid (6). The concentration device (2) comprises a filter (8) configured to filter particles (4) of a predefined size in the volume of the fluid (6). The concentration device (2) comprises...

  13. Microfluidic Device

    Science.gov (United States)

    Tai, Yu-Chong (Inventor); Zheng, Siyang (Inventor); Lin, Jeffrey Chun-Hui (Inventor); Kasdan, Harvey L. (Inventor)

    2016-01-01

    Described herein are particular embodiments relating to a microfluidic device that may be utilized for cell sensing, counting, and/or sorting. Particular aspects relate to a microfabricated device that is capable of differentiating single cell types from dense cell populations. One particular embodiment relates a device and methods of using the same for sensing, counting, and/or sorting leukocytes from whole, undiluted blood samples.

  14. Feedback system for divertor impurity seeding based on real-time measurements of surface heat flux in the Alcator C-Mod tokamak

    Science.gov (United States)

    Brunner, D.; Burke, W.; Kuang, A. Q.; LaBombard, B.; Lipschultz, B.; Wolfe, S.

    2016-02-01

    Mitigation of the intense heat flux to the divertor is one of the outstanding problems in fusion energy. One technique that has shown promise is impurity seeding, i.e., the injection of low-Z gaseous impurities (typically N2 or Ne) to radiate and dissipate the power before it arrives to the divertor target plate. To this end, the Alcator C-Mod team has created a first-of-its-kind feedback system to control the injection of seed gas based on real-time surface heat flux measurements. Surface thermocouples provide real-time measurements of the surface temperature response to the plasma heat flux. The surface temperature measurements are inputted into an analog computer that "solves" the 1-D heat transport equation to deliver accurate, real-time signals of the surface heat flux. The surface heat flux signals are sent to the C-Mod digital plasma control system, which uses a proportional-integral-derivative (PID) algorithm to control the duty cycle demand to a pulse width modulated piezo valve, which in turn controls the injection of gas into the private flux region of the C-Mod divertor. This paper presents the design and implementation of this new feedback system as well as initial results using it to control divertor heat flux.

  15. Transport-driven scrape-off layer flows and the x-point dependence of the L-H power threshold in Alcator C-Moda)

    Science.gov (United States)

    LaBombard, B.; Rice, J. E.; Hubbard, A. E.; Hughes, J. W.; Greenwald, M.; Granetz, R. S.; Irby, J. H.; Lin, Y.; Lipschultz, B.; Marmar, E. S.; Marr, K.; Mossessian, D.; Parker, R.; Rowan, W.; Smick, N.; Snipes, J. A.; Terry, J. L.; Wolfe, S. M.; Wukitch, S. J.

    2005-05-01

    Factor of ˜2 higher power thresholds for low- to high-confinement mode transitions (L-H) with unfavorable x-point topologies in Alcator C-Mod [Phys. Plasmas 1, 1511 (1994)] are linked to flow boundary conditions imposed by the scrape-off layer (SOL). Ballooning-like transport drives flow along magnetic field lines from low- to high-field regions with toroidal direction dependent on upper/lower x-point balance; the toroidal rotation of the confined plasma responds, exhibiting a strong counter-current rotation when B ×∇B points away from the x point. Increased auxiliary heating power (rf, no momentum input) leads to an L-H transition at approximately twice the edge electron pressure gradient when B ×∇B points away. As gradients rise prior to the transition, toroidal rotation ramps toward the co-current direction; the H mode is seen when the counter-current rotation imposed by the SOL flow becomes compensated. Remarkably, L-H thresholds in lower-limited discharges are identical to lower x-point discharges; SOL flows are also found similar, suggesting a connection.

  16. Feedback system for divertor impurity seeding based on real-time measurements of surface heat flux in the Alcator C-Mod tokamak.

    Science.gov (United States)

    Brunner, D; Burke, W; Kuang, A Q; LaBombard, B; Lipschultz, B; Wolfe, S

    2016-02-01

    Mitigation of the intense heat flux to the divertor is one of the outstanding problems in fusion energy. One technique that has shown promise is impurity seeding, i.e., the injection of low-Z gaseous impurities (typically N2 or Ne) to radiate and dissipate the power before it arrives to the divertor target plate. To this end, the Alcator C-Mod team has created a first-of-its-kind feedback system to control the injection of seed gas based on real-time surface heat flux measurements. Surface thermocouples provide real-time measurements of the surface temperature response to the plasma heat flux. The surface temperature measurements are inputted into an analog computer that "solves" the 1-D heat transport equation to deliver accurate, real-time signals of the surface heat flux. The surface heat flux signals are sent to the C-Mod digital plasma control system, which uses a proportional-integral-derivative (PID) algorithm to control the duty cycle demand to a pulse width modulated piezo valve, which in turn controls the injection of gas into the private flux region of the C-Mod divertor. This paper presents the design and implementation of this new feedback system as well as initial results using it to control divertor heat flux.

  17. Ferroelectric devices

    CERN Document Server

    Uchino, Kenji

    2009-01-01

    Updating its bestselling predecessor, Ferroelectric Devices, Second Edition assesses the last decade of developments-and setbacks-in the commercialization of ferroelectricity. Field pioneer and esteemed author Uchino provides insight into why this relatively nascent and interdisciplinary process has failed so far without a systematic accumulation of fundamental knowledge regarding materials and device development.Filling the informational void, this collection of information reviews state-of-the-art research and development trends reflecting nano and optical technologies, environmental regulat

  18. Ventricular assist device

    Science.gov (United States)

    VAD; RVAD; LVAD; BVAD; Right ventricular assist device; Left ventricular assist device; Biventricular assist device; Heart pump; Left ventricular assist system; LVAS; Implantable ventricular assist device

  19. Separating device

    NARCIS (Netherlands)

    De Jong, T.P.R.

    2001-01-01

    A sorting device (1) suitable for sorting wire from a waste stream, comprising a body (2) that moves when in use, and provided with spikes or similar projections. The body is embodied as a rotatable roll (2), which oscillates axially during its rotation. The roll is coupled to an oscillation engine

  20. Printing Device

    NARCIS (Netherlands)

    Berg, van den M.J.; Markies, P.R.; Zuilhof, H.

    2014-01-01

    An ink jetprinting device includes a pressure chamber formed by a plurality of wall segments, a first aperture extending through a wall segment and communicating with an ink jet orifice and a second aperture extending through a wall segment and communicating with an ink supply duct. The pressure cha

  1. Electrochemical device

    Science.gov (United States)

    Grimes, Patrick G.; Einstein, Harry; Bellows, Richard J.

    1988-01-12

    A tunnel protected electrochemical device features channels fluidically communicating between manifold, tunnels and cells. The channels are designed to provide the most efficient use of auxiliary power. The channels have a greater hydraulic pressure drop and electrical resistance than the manifold. This will provide a design with the optimum auxiliary energy requirements.

  2. Stratification devices

    DEFF Research Database (Denmark)

    Andersen, Elsa; Furbo, Simon

    2008-01-01

    results in longer operation periods and improved utilization of the solar collector. Thermal stratification can be achieved, for example by using inlet stratification devices at all inlets to the storage tank. This paper presents how thermal stratification is established and utilized by means of inlet...

  3. "Distinvar" device

    CERN Multimedia

    1965-01-01

    The alignment of one of the accelerator magnets being checked by the AR Division survey group. A "distinvar" device, invented by the group, using calibrated invar wires stretched between the fixed survey pillar (on the left) and a fixed point on the magnet. In two days it is thus possible to measure the alignment of the 100 magnets with an accuracy better than 1/10.

  4. Electrooptical devices

    Science.gov (United States)

    Hurwitz, C. E.

    1980-03-01

    This report covers work carried out with support of the Department of the Air Force during the period 1 October 1979 through 31 March 1980. A part of this support was provided by the Rome Air Development Center. CW operation at temperatures up to 55 C has been achieved for GaInAsP/InP double-heterostructure (DH) lasers emitting at 1.5 micrometers, which were grown without a GaInAsP buffer layer. These devices are of interest for use as sources in fiber-optics communications systems, since the lowest transmission loss reported for fused-silica optical fibers occurs at 1.55 micrometers. Surface passivation techniques developed for InP and GaInAsP avalanche photodiodes have resulted in reductions of dark current as large as four orders of magnitude, to values as low as .0000016 A/sq cm at 0.9 V(b) where V(b) is the breakdown voltage. Devices consisting entirely of InP have been passivated with plasma-deposited Si3N4, and those with a GaInAsP layer but with the p-n junction in InP have been passivated with polyimide. Neither of these techniques successfully reduces dark currents in devices with the p-n junction in the GaInAsP, but a film of photoresist sprayed with SF6 as the propellant has given excellent results. The electrical characteristics in InP ion implanted with Sn, Ge, Si, and C have been investigated. All of these column IV elements yielded n-type conductivity and Sn, Ge, and Si showed high electrical activation; however, implanted C was found to have a net electrical activation of only about 5 percent.

  5. Scalable devices

    KAUST Repository

    Krüger, Jens J.

    2014-01-01

    In computer science in general and in particular the field of high performance computing and supercomputing the term scalable plays an important role. It indicates that a piece of hardware, a concept, an algorithm, or an entire system scales with the size of the problem, i.e., it can not only be used in a very specific setting but it\\'s applicable for a wide range of problems. From small scenarios to possibly very large settings. In this spirit, there exist a number of fixed areas of research on scalability. There are works on scalable algorithms, scalable architectures but what are scalable devices? In the context of this chapter, we are interested in a whole range of display devices, ranging from small scale hardware such as tablet computers, pads, smart-phones etc. up to large tiled display walls. What interests us mostly is not so much the hardware setup but mostly the visualization algorithms behind these display systems that scale from your average smart phone up to the largest gigapixel display walls.

  6. Thermonuclear device

    International Nuclear Information System (INIS)

    Purpose: To absorb fabrication errors in radial toroidal coils and a spacer and completely fill the gap between them by the provision of an expansion device between the coils and the supporting spacer by injecting fillers of a predetermined composition. Constitution: An expansion device comprising an expansion plate, packings inserted into grooves formed in the outer circumference of the expansion plate and a recessed pressure receiving plate is inserted between the wall surface of radial toroidal coils and a spacer for maintaining the gap between the toroidal coils. Then, filler comprising polyester resin and glass beads incorporated therein is injected from an injection aperture of the recessed pressure receiving plate having an exhaust aperture at the upper part. The filler is solidified and enables the fabrication error in the coils and the spacer to be absorbed. Since the gap between the coils and the spacer is completely filled, the tumbling force of the coils can surely be transmitted by way of the spacer to upper and lower racks. (Moriyama, K.)

  7. Practical microwave electron devices

    CERN Document Server

    Meurant, Gerard

    2013-01-01

    Practical Microwave Electron Devices provides an understanding of microwave electron devices and their applications. All areas of microwave electron devices are covered. These include microwave solid-state devices, including popular microwave transistors and both passive and active diodes; quantum electron devices; thermionic devices (including relativistic thermionic devices); and ferrimagnetic electron devices. The design of each of these devices is discussed as well as their applications, including oscillation, amplification, switching, modulation, demodulation, and parametric interactions.

  8. PLASMA DEVICE

    Science.gov (United States)

    Baker, W.R.

    1961-08-22

    A device is described for establishing and maintaining a high-energy, rotational plasma for use as a fast discharge capacitor. A disc-shaped, current- conducting plasma is formed in an axinl magnetic field and a crossed electric field, thereby creating rotational kinetic enengy in the plasma. Such energy stored in the rotation of the plasma disc is substantial and is convertible tc electrical energy by generator action in an output line electrically coupled to the plasma volume. Means are then provided for discharging the electrical energy into an external circuit coupled to the output line to produce a very large pulse having an extremely rapid rise time in the waveform thereof. (AE C)

  9. Laser device

    Science.gov (United States)

    Scott, Jill R.; Tremblay, Paul L.

    2007-07-10

    A laser device includes a target position, an optical component separated a distance J from the target position, and a laser energy source separated a distance H from the optical component, distance H being greater than distance J. A laser source manipulation mechanism exhibits a mechanical resolution of positioning the laser source. The mechanical resolution is less than a spatial resolution of laser energy at the target position as directed through the optical component. A vertical and a lateral index that intersect at an origin can be defined for the optical component. The manipulation mechanism can auto align laser aim through the origin during laser source motion. The laser source manipulation mechanism can include a mechanical index. The mechanical index can include a pivot point for laser source lateral motion and a reference point for laser source vertical motion. The target position can be located within an adverse environment including at least one of a high magnetic field, a vacuum system, a high pressure system, and a hazardous zone. The laser source and an electro-mechanical part of the manipulation mechanism can be located outside the adverse environment. The manipulation mechanism can include a Peaucellier linkage.

  10. Characterization and performance of a field aligned ion cyclotron range of frequency antenna in Alcator C-Moda)

    Science.gov (United States)

    Wukitch, S. J.; Garrett, M. L.; Ochoukov, R.; Terry, J. L.; Hubbard, A.; Labombard, B.; Lau, C.; Lin, Y.; Lipschultz, B.; Miller, D.; Reinke, M. L.; Whyte, D.; Alcator C-Mod Team

    2013-05-01

    Ion cyclotron range of frequency (ICRF) heating is expected to provide auxiliary heating for ITER and future fusion reactors where high Z metallic plasma facing components (PFCs) are being considered. Impurity contamination linked to ICRF antenna operation remains a major challenge particularly for devices with high Z metallic PFCs. Here, we report on an experimental investigation to test whether a field aligned (FA) antenna can reduce impurity contamination and impurity sources. We compare the modification of the scrape of layer (SOL) plasma potential of the FA antenna to a conventional, toroidally aligned (TA) antenna, in order to explore the underlying physics governing impurity contamination linked to ICRF heating. The FA antenna is a 4-strap ICRF antenna where the current straps and antenna enclosure sides are perpendicular to the total magnetic field while the Faraday screen rods are parallel to the total magnetic field. In principle, alignment with respect to the total magnetic field minimizes integrated E|| (electric field along a magnetic field line) via symmetry. A finite element method RF antenna model coupled to a cold plasma model verifies that the integrated E|| should be reduced for all antenna phases. Monopole phasing in particular is expected to have the lowest integrated E||. Consistent with expectations, we observed that the impurity contamination and impurity source at the FA antenna are reduced compared to the TA antenna. In both L and H-mode discharges, the radiated power is 20%-30% lower for a FA-antenna heated discharge than a discharge heated with the TA-antennas. However, inconsistent with expectations, we observe RF induced plasma potentials (via gas-puff imaging and emissive probes to be nearly identical for FA and TA antennas when operated in dipole phasing). Moreover, the highest levels of RF-induced plasma potentials are observed using monopole phasing with the FA antenna. Thus, while impurity contamination and sources are indeed

  11. Characterization and performance of a field aligned ion cyclotron range of frequency antenna in Alcator C-Mod

    Energy Technology Data Exchange (ETDEWEB)

    Wukitch, S. J.; Garrett, M. L.; Ochoukov, R.; Terry, J. L.; Hubbard, A.; Labombard, B.; Lau, C.; Lin, Y.; Lipschultz, B.; Miller, D.; Reinke, M. L.; Whyte, D. [MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139 (United States); Collaboration: Alcator C-Mod Team

    2013-05-15

    Ion cyclotron range of frequency (ICRF) heating is expected to provide auxiliary heating for ITER and future fusion reactors where high Z metallic plasma facing components (PFCs) are being considered. Impurity contamination linked to ICRF antenna operation remains a major challenge particularly for devices with high Z metallic PFCs. Here, we report on an experimental investigation to test whether a field aligned (FA) antenna can reduce impurity contamination and impurity sources. We compare the modification of the scrape of layer (SOL) plasma potential of the FA antenna to a conventional, toroidally aligned (TA) antenna, in order to explore the underlying physics governing impurity contamination linked to ICRF heating. The FA antenna is a 4-strap ICRF antenna where the current straps and antenna enclosure sides are perpendicular to the total magnetic field while the Faraday screen rods are parallel to the total magnetic field. In principle, alignment with respect to the total magnetic field minimizes integrated E|| (electric field along a magnetic field line) via symmetry. A finite element method RF antenna model coupled to a cold plasma model verifies that the integrated E|| should be reduced for all antenna phases. Monopole phasing in particular is expected to have the lowest integrated E||. Consistent with expectations, we observed that the impurity contamination and impurity source at the FA antenna are reduced compared to the TA antenna. In both L and H-mode discharges, the radiated power is 20%–30% lower for a FA-antenna heated discharge than a discharge heated with the TA-antennas. However, inconsistent with expectations, we observe RF induced plasma potentials (via gas-puff imaging and emissive probes to be nearly identical for FA and TA antennas when operated in dipole phasing). Moreover, the highest levels of RF-induced plasma potentials are observed using monopole phasing with the FA antenna. Thus, while impurity contamination and sources are indeed

  12. Characterization and performance of a field aligned ion cyclotron range of frequency antenna in Alcator C-Mod

    International Nuclear Information System (INIS)

    Ion cyclotron range of frequency (ICRF) heating is expected to provide auxiliary heating for ITER and future fusion reactors where high Z metallic plasma facing components (PFCs) are being considered. Impurity contamination linked to ICRF antenna operation remains a major challenge particularly for devices with high Z metallic PFCs. Here, we report on an experimental investigation to test whether a field aligned (FA) antenna can reduce impurity contamination and impurity sources. We compare the modification of the scrape of layer (SOL) plasma potential of the FA antenna to a conventional, toroidally aligned (TA) antenna, in order to explore the underlying physics governing impurity contamination linked to ICRF heating. The FA antenna is a 4-strap ICRF antenna where the current straps and antenna enclosure sides are perpendicular to the total magnetic field while the Faraday screen rods are parallel to the total magnetic field. In principle, alignment with respect to the total magnetic field minimizes integrated E|| (electric field along a magnetic field line) via symmetry. A finite element method RF antenna model coupled to a cold plasma model verifies that the integrated E|| should be reduced for all antenna phases. Monopole phasing in particular is expected to have the lowest integrated E||. Consistent with expectations, we observed that the impurity contamination and impurity source at the FA antenna are reduced compared to the TA antenna. In both L and H-mode discharges, the radiated power is 20%–30% lower for a FA-antenna heated discharge than a discharge heated with the TA-antennas. However, inconsistent with expectations, we observe RF induced plasma potentials (via gas-puff imaging and emissive probes to be nearly identical for FA and TA antennas when operated in dipole phasing). Moreover, the highest levels of RF-induced plasma potentials are observed using monopole phasing with the FA antenna. Thus, while impurity contamination and sources are indeed

  13. Infrared criminalistic devices

    Science.gov (United States)

    Gibin, Igor S.; Savkov, E. V.; Popov, Pavel G.

    1996-12-01

    We are presenting the devices of near-IR spectral range in this report. The devices may be used in criminalistics, in bank business, in restoration works, etc. the action principle of these devices is describing briefly.

  14. Intrauterine devices (IUD)

    Science.gov (United States)

    ... medlineplus.gov/ency/article/007635.htm Intrauterine devices (IUD) To use the sharing features on this page, please enable JavaScript. An intrauterine device (IUD) is a small plastic T-shaped device used ...

  15. Medical Device Safety

    Science.gov (United States)

    A medical device is any product used to diagnose, cure, or treat a condition, or to prevent disease. They ... may need one in a hospital. To use medical devices safely Know how your device works. Keep ...

  16. Implantable electronic medical devices

    CERN Document Server

    Fitzpatrick, Dennis

    2014-01-01

    Implantable Electronic Medical Devices provides a thorough review of the application of implantable devices, illustrating the techniques currently being used together with overviews of the latest commercially available medical devices. This book provides an overview of the design of medical devices and is a reference on existing medical devices. The book groups devices with similar functionality into distinct chapters, looking at the latest design ideas and techniques in each area, including retinal implants, glucose biosensors, cochlear implants, pacemakers, electrical stimulation t

  17. Ultraefficient Themoelectric Devices Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Thermoelectric (TE) devices already found a wide range of commercial, military and aerospace applications. However, at present commercially available TE devices...

  18. Implantable CMOS Biomedical Devices

    Directory of Open Access Journals (Sweden)

    Toshihiko Noda

    2009-11-01

    Full Text Available The results of recent research on our implantable CMOS biomedical devices are reviewed. Topics include retinal prosthesis devices and deep-brain implantation devices for small animals. Fundamental device structures and characteristics as well as in vivo experiments are presented.

  19. Hip supporting device

    DEFF Research Database (Denmark)

    2011-01-01

    The present invention relates to a device for limiting movements in one or more anatomical joints, such as a device for limiting movement in the human hip joint after hip replacement surgery. This is provided by a device for limiting movement in the human hip joint, said device comprising: at least...

  20. Rhetorical Devices in English Advertisements

    Institute of Scientific and Technical Information of China (English)

    陈芃

    2011-01-01

    In order to achieve persuasive and convincing effects,rhetorical devices are frequently applied in English advertisements.The paper classifies rhetorical devices into four basic categories: phonetic devices,lexical devices,syntactic devices and figures of

  1. Alerts and Notices (Devices)

    Science.gov (United States)

    ... powered, Hand-held Lasers Used for Pointing or Entertainment 12/16/10 Medical Device Safety Archive The ... About FDA Contact FDA Browse by Product Area Product Areas back Food Drugs Medical Devices Radiation-Emitting ...

  2. Development of Medical Devices

    OpenAIRE

    Limaye, Dnyanesh

    2016-01-01

    The medical devices sector helps save lives by providing innovative health care solutions regarding diagnosis, prevention, monitoring, treatment, and alleviation. Medical devices are classified into 1 of 3 categories in the order of increasing risk: Class I, Class II, and Class III.1 Medical devices are distinguished from drugs for regulatory purposes based on mechanism of action. Unlike drugs, medical devices operate via physical or mechanical means and are not dependent on metabolism to acc...

  3. Smart devices are different

    DEFF Research Database (Denmark)

    Stisen, Allan; Blunck, Henrik; Bhattacharya, Sourav;

    2015-01-01

    research results. This is due to variations in training and test device hardware and their operating system characteristics among others. In this paper, we systematically investigate sensor-, device- and workload-specific heterogeneities using 36 smartphones and smartwatches, consisting of 13 different...... device models from four manufacturers. Furthermore, we conduct experiments with nine users and investigate popular feature representation and classification techniques in HAR research. Our results indicate that on-device sensor and sensor handling heterogeneities impair HAR performances significantly...

  4. Heterostructures and quantum devices

    CERN Document Server

    Einspruch, Norman G

    1994-01-01

    Heterostructure and quantum-mechanical devices promise significant improvement in the performance of electronic and optoelectronic integrated circuits (ICs). Though these devices are the subject of a vigorous research effort, the current literature is often either highly technical or narrowly focused. This book presents heterostructure and quantum devices to the nonspecialist, especially electrical engineers working with high-performance semiconductor devices. It focuses on a broad base of technical applications using semiconductor physics theory to develop the next generation of electrical en

  5. Photovoltaic device and method

    Science.gov (United States)

    Cleereman, Robert; Lesniak, Michael J.; Keenihan, James R.; Langmaid, Joe A.; Gaston, Ryan; Eurich, Gerald K.; Boven, Michelle L.

    2015-11-24

    The present invention is premised upon an improved photovoltaic device ("PVD") and method of use, more particularly to an improved photovoltaic device with an integral locator and electrical terminal mechanism for transferring current to or from the improved photovoltaic device and the use as a system.

  6. Photovoltaic device and method

    Science.gov (United States)

    Cleereman, Robert J; Lesniak, Michael J; Keenihan, James R; Langmaid, Joe A; Gaston, Ryan; Eurich, Gerald K; Boven, Michelle L

    2015-01-27

    The present invention is premised upon an improved photovoltaic device ("PVD") and method of use, more particularly to an improved photovoltaic device with an integral locator and electrical terminal mechanism for transferring current to or from the improved photovoltaic device and the use as a system.

  7. Organic photosensitive devices

    Science.gov (United States)

    Rand, Barry P; Forrest, Stephen R

    2013-11-26

    The present invention generally relates to organic photosensitive optoelectronic devices. More specifically, it is directed to organic photosensitive optoelectronic devices having a photoactive organic region containing encapsulated nanoparticles that exhibit plasmon resonances. An enhancement of the incident optical field is achieved via surface plasmon polariton resonances. This enhancement increases the absorption of incident light, leading to a more efficient device.

  8. Thermography of electronic devices

    Directory of Open Access Journals (Sweden)

    Panfilova S. P.

    2007-12-01

    Full Text Available The possibility of application of thermography to diagnose the electronic devices is analyzed in the article. Typical faults of electronic devices which can be found by means of thermography are given. Advantages of noncontact thermal inspection in comparison with the contact one are described. Some features of thermography of electronic devices are considered. Thermography apparatus is viewed and some pieces of advice about choosing it for electronic devices diagnosis are given. An example of the thermographic method for checking the electronic devices is provided. The main features of software used in thermography and its significance are described.

  9. FLUIDICS DEVICE FOR ASSAY

    DEFF Research Database (Denmark)

    2007-01-01

    The present invention relates to a device for use in performing assays on standard laboratory solid supports whereon chemical entities are attached. The invention furthermore relates to the use of such a device and a kit comprising such a device. The device according to the present invention is a......, when operatively connected, one or more chambers (21) comprising the chemical entities (41), the inlet(s) (5) and outlet(s) (6) and chambers (21) being in fluid connection. The device further comprise means for providing differing chemical conditions in each chamber (21)....

  10. Optical plasma microelectronic devices

    CERN Document Server

    Forati, Ebrahim; Dill, Thyler; Sievenpiper, Dan

    2015-01-01

    The semiconductor channel in conventional microelectronic devices was successfully replaced with an optically triggered gas plasma channel. The combination of DC and laser-induced gas ionizations controls the conductivity of the channel, enabling us to realize different electronic devices such as transistors, switches, modulators, etc. A special micro-scale metasurface was used to enhance the laser-gas interaction, as well as combining it with DC ionization properly. Optical plasma devices benefit form the advantages of plasma/vacuum electronic devices while preserving most of the integrablity of semiconductor based devices.

  11. Unitary lens semiconductor device

    Science.gov (United States)

    Lear, Kevin L.

    1997-01-01

    A unitary lens semiconductor device and method. The unitary lens semiconductor device is provided with at least one semiconductor layer having a composition varying in the growth direction for unitarily forming one or more lenses in the semiconductor layer. Unitary lens semiconductor devices may be formed as light-processing devices such as microlenses, and as light-active devices such as light-emitting diodes, photodetectors, resonant-cavity light-emitting diodes, vertical-cavity surface-emitting lasers, and resonant cavity photodetectors.

  12. Radiation emitting devices regulations

    International Nuclear Information System (INIS)

    The Radiation Emitting Devices Regulations are the regulations referred to in the Radiation Emitting Devices Act and relate to the operation of devices. They include standards of design and construction, standards of functioning, warning symbol specifications in addition to information relating to the seizure and detention of machines failing to comply with the regulations. The radiation emitting devices consist of the following: television receivers, extra-oral dental x-ray equipment, microwave ovens, baggage inspection x-ray devices, demonstration--type gas discharge devices, photofluorographic x-ray equipment, laser scanners, demonstration lasers, low energy electron microscopes, high intensity mercury vapour discharge lamps, sunlamps, diagnostic x-ray equipment, ultrasound therapy devices, x-ray diffraction equipment, cabinet x-ray equipment and therapeutic x-ray equipment

  13. Smart portable rehabilitation devices

    Directory of Open Access Journals (Sweden)

    Leahey Matt

    2005-07-01

    Full Text Available Abstract Background The majority of current portable orthotic devices and rehabilitative braces provide stability, apply precise pressure, or help maintain alignment of the joints with out the capability for real time monitoring of the patient's motions and forces and without the ability for real time adjustments of the applied forces and motions. Improved technology has allowed for advancements where these devices can be designed to apply a form of tension to resist motion of the joint. These devices induce quicker recovery and are more effective at restoring proper biomechanics and improving muscle function. However, their shortcoming is in their inability to be adjusted in real-time, which is the most ideal form of a device for rehabilitation. This introduces a second class of devices beyond passive orthotics. It is comprised of "active" or powered devices, and although more complicated in design, they are definitely the most versatile. An active or powered orthotic, usually employs some type of actuator(s. Methods In this paper we present several new advancements in the area of smart rehabilitation devices that have been developed by the Northeastern University Robotics and Mechatronics Laboratory. They are all compact, wearable and portable devices and boast re-programmable, real time computer controlled functions as the central theme behind their operation. The sensory information and computer control of the three described devices make for highly efficient and versatile systems that represent a whole new breed in wearable rehabilitation devices. Their applications range from active-assistive rehabilitation to resistance exercise and even have applications in gait training. The three devices described are: a transportable continuous passive motion elbow device, a wearable electro-rheological fluid based knee resistance device, and a wearable electrical stimulation and biofeedback knee device. Results Laboratory tests of the devices

  14. Mechanical CPR devices

    OpenAIRE

    Halperin, Henry; Carver, David J.

    2010-01-01

    It is recognized that the quality of cardiopulmonary resuscitation (CPR) is an important predictor of outcome from cardiac arrest. Mechanical chest-compression devices provide an alternative to manual CPR. Physiological and animal data suggest that mechanical chest-compression devices are more effective than manual CPR. Consequently, there has been much interest in the development of new techniques and devices to improve the efficacy of CPR. This review will consider the evidence ...

  15. Optical fibre nanowire devices

    OpenAIRE

    Xu, Fei

    2008-01-01

    The Optical Fibre Nanowire (OFN) is a potential building block in future micro- and nano-photonic device since it offers a number of unique optical and mechanical properties. In this thesis, the background and fundamental features of nanowires are introduced; the theory, design and demonstration of novel nanowire devices are discussed. At first, a short adiabatic taper tip is manufactured, and it is used as optical tweezers for trapping 1?m microspheres. Then, the most important devic...

  16. Sensor sentinel computing device

    Energy Technology Data Exchange (ETDEWEB)

    Damico, Joseph P.

    2016-08-02

    Technologies pertaining to authenticating data output by sensors in an industrial environment are described herein. A sensor sentinel computing device receives time-series data from a sensor by way of a wireline connection. The sensor sentinel computing device generates a validation signal that is a function of the time-series signal. The sensor sentinel computing device then transmits the validation signal to a programmable logic controller in the industrial environment.

  17. Establishment Registration & Device Listing

    Data.gov (United States)

    U.S. Department of Health & Human Services — This searchable database contains establishments (engaged in the manufacture, preparation, propagation, compounding, assembly, or processing of medical devices...

  18. New Medical Device Evaluation.

    Science.gov (United States)

    Ikeda, Koji

    2016-01-01

    In this presentation, as a member of the Harmonization by Doing (HBD) project, I discuss the significance of regulatory science in global medical device development and our experience in the international collaboration process for medical devices. In Japan, most innovative medical therapeutic devices were previously developed and exported by foreign-based companies. Due to this device lag, Japanese had minimal opportunities for receiving treatment with innovative medical devices. To address this issue, the Japanese government has actively accepted foreign clinical trial results and promoted global clinical trials in projects such as HBD. HBD is a project with stakeholders from academia, regulatory authorities, and industry in the US and Japan to promote global clinical trials and reduce device lags. When the project started, medical device clinical trials were not actively conducted in Japan at not just hospitals but also at medical device companies. We started to identify issues under the concept of HBD. After 10 years, we have now become key members in global clinical trials and able to obtain approvals without delay. Recently, HBD has started promoting international convergence. Physicians and regulatory authorities play central roles in compiling guidelines for the clinical evaluation of medical device development, which will be a more active field in the near future. The guidelines compiled will be confirmed with members of academia and regulatory authorities in the United Sates. PMID:27040333

  19. Virtual Training Devices Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Virtual Training Devices (VTD) Laboratory at the Life Cycle Software Engineering Center, Picatinny Arsenal, provides a software testing and support environment...

  20. Cataphoric Devices in Spoken Discourse

    OpenAIRE

    Gernsbacher, Morton Ann; Jescheniak, Jörg D.

    1995-01-01

    We propose that speakers mark key words with cataphoric devices. Cataphoric devices are counterparts to anaphoric devices: Just as anaphoric devices enable backward reference, cataphoric devices enable forward reference. And just as anaphoric devices mark concepts that have been mentioned before, cataphoric devices mark concepts that are likely to be mentioned again. We investigated two cataphoric devices: spoken stress and the indefinite this. Our experiments demonstrated three ways that con...

  1. Vaginal mechanical contraceptive devices.

    OpenAIRE

    Smith, M.; Barwin, B. N.

    1983-01-01

    The alleged adverse effects of oral contraceptives and intrauterine devices have led to increased consumer and physician demand for vaginal contraceptive devices. The efficacy and the advantages and disadvantages of vaginal sponges, cervical caps and diaphragms are discussed and compared in this article.

  2. Microfabricated particle focusing device

    Energy Technology Data Exchange (ETDEWEB)

    Ravula, Surendra K.; Arrington, Christian L.; Sigman, Jennifer K.; Branch, Darren W.; Brener, Igal; Clem, Paul G.; James, Conrad D.; Hill, Martyn; Boltryk, Rosemary June

    2013-04-23

    A microfabricated particle focusing device comprises an acoustic portion to preconcentrate particles over large spatial dimensions into particle streams and a dielectrophoretic portion for finer particle focusing into single-file columns. The device can be used for high throughput assays for which it is necessary to isolate and investigate small bundles of particles and single particles.

  3. Unconventional Quantum Computing Devices

    OpenAIRE

    Lloyd, Seth

    2000-01-01

    This paper investigates a variety of unconventional quantum computation devices, including fermionic quantum computers and computers that exploit nonlinear quantum mechanics. It is shown that unconventional quantum computing devices can in principle compute some quantities more rapidly than `conventional' quantum computers.

  4. Digital communication device

    DEFF Research Database (Denmark)

    2005-01-01

    The invention concerns a digital communication device like a hearing aid or a headset. The hearing aid or headset has a power supply, a signal processing device, means for receiving a wireless signal and a receiver or loudspeaker, which produces an audio signal based on a modulated pulsed signal...

  5. Metallic spintronic devices

    CERN Document Server

    Wang, Xiaobin

    2014-01-01

    Metallic Spintronic Devices provides a balanced view of the present state of the art of metallic spintronic devices, addressing both mainstream and emerging applications from magnetic tunneling junction sensors and spin torque oscillators to spin torque memory and logic. Featuring contributions from well-known and respected industrial and academic experts, this cutting-edge work not only presents the latest research and developments but also: Describes spintronic applications in current and future magnetic recording devicesDiscusses spin-transfer torque magnetoresistive random-access memory (STT-MRAM) device architectures and modelingExplores prospects of STT-MRAM scaling, such as detailed multilevel cell structure analysisInvestigates spintronic device write and read optimization in light of spintronic memristive effectsConsiders spintronic research directions based on yttrium iron garnet thin films, including spin pumping, magnetic proximity, spin hall, and spin Seebeck effectsProposes unique solutions for ...

  6. Compound semiconductor device modelling

    CERN Document Server

    Miles, Robert

    1993-01-01

    Compound semiconductor devices form the foundation of solid-state microwave and optoelectronic technologies used in many modern communication systems. In common with their low frequency counterparts, these devices are often represented using equivalent circuit models, but it is often necessary to resort to physical models in order to gain insight into the detailed operation of compound semiconductor devices. Many of the earliest physical models were indeed developed to understand the 'unusual' phenomena which occur at high frequencies. Such was the case with the Gunn and IMPATI diodes, which led to an increased interest in using numerical simulation methods. Contemporary devices often have feature sizes so small that they no longer operate within the familiar traditional framework, and hot electron or even quantum­ mechanical models are required. The need for accurate and efficient models suitable for computer aided design has increased with the demand for a wider range of integrated devices for operation at...

  7. Positioning devices for patients

    International Nuclear Information System (INIS)

    It has been suggested that it is very important to position patients reproducibly at different stages of radiotherapy treatment planning and treatment, or similar procedures. Devices have been described for positioning a patient's upper and lower thorax. This invention provides reproducible positioning for a female patient's breasts, for example in planning treatment of and treating breast tumours. The patient is placed prone, using for example an upper thorax device. A support device is placed central to and beneath her breasts to partially displace them outwards. The device may be triangular in section with one apex contacting the chest wall at the sternum. Restraining straps may be provided to hold the breasts against the support device. Means may be provided to take a healthy breast from the path of radiation through the tumour. (author)

  8. Planar electrochemical device assembly

    Science.gov (United States)

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

    2007-06-19

    A pre-fabricated electrochemical device having a dense electrolyte disposed between an anode and a cathode preferably deposited as thin films is bonded to a porous electrically conductive support. A second porous electrically conductive support may be bonded to a counter electrode of the electrochemical device. Multiple electrochemical devices may be bonded in parallel to a single porous support, such as a perforated sheet to provide a planar array. Planar arrays may be arranged in a stacked interconnected array. A method of making a supported electrochemical device is disclosed wherein the method includes a step of bonding a pre-fabricated electrochemical device layer to an existing porous metal or porous metal alloy layer.

  9. Fluidic nanotubes and devices

    Science.gov (United States)

    Yang, Peidong; He, Rongrui; Goldberger, Joshua; Fan, Rong; Wu, Yiying; Li, Deyu; Majumdar, Arun

    2008-04-08

    Fluidic nanotube devices are described in which a hydrophilic, non-carbon nanotube, has its ends fluidly coupled to reservoirs. Source and drain contacts are connected to opposing ends of the nanotube, or within each reservoir near the opening of the nanotube. The passage of molecular species can be sensed by measuring current flow (source-drain, ionic, or combination). The tube interior can be functionalized by joining binding molecules so that different molecular species can be sensed by detecting current changes. The nanotube may be a semiconductor, wherein a tubular transistor is formed. A gate electrode can be attached between source and drain to control current flow and ionic flow. By way of example an electrophoretic array embodiment is described, integrating MEMs switches. A variety of applications are described, such as: nanopores, nanocapillary devices, nanoelectrophoretic, DNA sequence detectors, immunosensors, thermoelectric devices, photonic devices, nanoscale fluidic bioseparators, imaging devices, and so forth.

  10. Nanoelectronic device applications handbook

    CERN Document Server

    Morris, James E

    2013-01-01

    Nanoelectronic Device Applications Handbook gives a comprehensive snapshot of the state of the art in nanodevices for nanoelectronics applications. Combining breadth and depth, the book includes 68 chapters on topics that range from nano-scaled complementary metal-oxide-semiconductor (CMOS) devices through recent developments in nano capacitors and AlGaAs/GaAs devices. The contributors are world-renowned experts from academia and industry from around the globe. The handbook explores current research into potentially disruptive technologies for a post-CMOS world.These include: Nanoscale advance

  11. Electronic devices and circuits

    CERN Document Server

    Pridham, Gordon John

    1972-01-01

    Electronic Devices and Circuits, Volume 3 provides a comprehensive account on electronic devices and circuits and includes introductory network theory and physics. The physics of semiconductor devices is described, along with field effect transistors, small-signal equivalent circuits of bipolar transistors, and integrated circuits. Linear and non-linear circuits as well as logic circuits are also considered. This volume is comprised of 12 chapters and begins with an analysis of the use of Laplace transforms for analysis of filter networks, followed by a discussion on the physical properties of

  12. Output hardcopy devices

    CERN Document Server

    Durbeck, Robert

    1988-01-01

    Output Hardcopy Devices provides a technical summary of computer output hardcopy devices such as plotters, computer output printers, and CRT generated hardcopy. Important related technical areas such as papers, ribbons and inks, color techniques, controllers, and character fonts are also covered. Emphasis is on techniques primarily associated with printing, as well as the plotting capabilities of printing devices that can be effectively used for computer graphics in addition to their various printing functions. Comprised of 19 chapters, this volume begins with an introduction to vector and ras

  13. Radiations from display devices

    International Nuclear Information System (INIS)

    45 display devices have been analyzed for X-ray emmission and for electrostatic - and low-frequency magnetic fields. 3 have been further analyzed for UV and visible light emmission. No emmissions above established risk levels have been found. For low-frequency magnetic fields very little is known of risks, so the levels have been compared with other commonly used devices. The measured levels correspond roughly to that which occur in the use of an electrical egg-beater, or a small hand electrical drill. Data are presented for the tested devices.(author)

  14. Compound semiconductor device physics

    CERN Document Server

    Tiwari, Sandip

    2013-01-01

    This book provides one of the most rigorous treatments of compound semiconductor device physics yet published. A complete understanding of modern devices requires a working knowledge of low-dimensional physics, the use of statistical methods, and the use of one-, two-, and three-dimensional analytical and numerical analysis techniques. With its systematic and detailed**discussion of these topics, this book is ideal for both the researcher and the student. Although the emphasis of this text is on compound semiconductor devices, many of the principles discussed will also be useful to those inter

  15. Emission rate measuring device

    Science.gov (United States)

    Luckat, S.

    1980-09-01

    The development and application of an emission rate measuring device for gaseous components is explored. The device contains absorption fluid from a supply container that moistens a cylindrical paper sleeve. A newer model is provided with a direct current motor requiring less electricity than an older model. The hose pump is modified to avoid changing it and the filter sleeve is fastened more securely to the distributor head. Application of the measuring devices is discussed, particularly at the Cologne Cathedral, where damage to the stone is observed.

  16. Physics of photonic devices

    CERN Document Server

    Chuang, Shun Lien

    2009-01-01

    The most up-to-date book available on the physics of photonic devices This new edition of Physics of Photonic Devices incorporates significant advancements in the field of photonics that have occurred since publication of the first edition (Physics of Optoelectronic Devices). New topics covered include a brief history of the invention of semiconductor lasers, the Lorentz dipole method and metal plasmas, matrix optics, surface plasma waveguides, optical ring resonators, integrated electroabsorption modulator-lasers, and solar cells. It also introduces exciting new fields of research such as:

  17. Powering biomedical devices

    CERN Document Server

    Romero, Edwar

    2013-01-01

    From exoskeletons to neural implants, biomedical devices are no less than life-changing. Compact and constant power sources are necessary to keep these devices running efficiently. Edwar Romero's Powering Biomedical Devices reviews the background, current technologies, and possible future developments of these power sources, examining not only the types of biomedical power sources available (macro, mini, MEMS, and nano), but also what they power (such as prostheses, insulin pumps, and muscular and neural stimulators), and how they work (covering batteries, biofluids, kinetic and ther

  18. Microreactor Array Device

    Science.gov (United States)

    Wiktor, Peter; Brunner, Al; Kahn, Peter; Qiu, Ji; Magee, Mitch; Bian, Xiaofang; Karthikeyan, Kailash; Labaer, Joshua

    2015-03-01

    We report a device to fill an array of small chemical reaction chambers (microreactors) with reagent and then seal them using pressurized viscous liquid acting through a flexible membrane. The device enables multiple, independent chemical reactions involving free floating intermediate molecules without interference from neighboring reactions or external environments. The device is validated by protein expressed in situ directly from DNA in a microarray of ~10,000 spots with no diffusion during three hours incubation. Using the device to probe for an autoantibody cancer biomarker in blood serum sample gave five times higher signal to background ratio compared to standard protein microarray expressed on a flat microscope slide. Physical design principles to effectively fill the array of microreactors with reagent and experimental results of alternate methods for sealing the microreactors are presented.

  19. Advanced underwater lift device

    Science.gov (United States)

    Flanagan, David T.; Hopkins, Robert C.

    1993-01-01

    Flexible underwater lift devices ('lift bags') are used in underwater operations to provide buoyancy to submerged objects. Commercially available designs are heavy, bulky, and awkward to handle, and thus are limited in size and useful lifting capacity. An underwater lift device having less than 20 percent of the bulk and less than 10 percent of the weight of commercially available models was developed. The design features a dual membrane envelope, a nearly homogeneous envelope membrane stress distribution, and a minimum surface-to-volume ratio. A proof-of-concept model of 50 kg capacity was built and tested. Originally designed to provide buoyancy to mock-ups submerged in NASA's weightlessness simulators, the device may have application to water-landed spacecraft which must deploy flotation upon impact, and where launch weight and volume penalties are significant. The device may also be useful for the automated recovery of ocean floor probes or in marine salvage applications.

  20. Dielectrophoretically tunable optofluidic devices

    Science.gov (United States)

    Xu, Su; Ren, Hongwen; Wu, Shin-Tson

    2013-12-01

    Tunable optofluidic devices exhibit some unique characteristics that are not achievable in conventional solid-state photonic devices. They provide exciting opportunities for emerging applications in imaging, information processing, sensing, optical communication, lab-on-a-chip and biomedical engineering. A dielectrophoresis effect is an important physical mechanism to realize tunable optofluidic devices. Via balancing the voltage-induced dielectric force and interfacial tension, the liquid interface can be dynamically manipulated and the optical output reconfigured or adaptively tuned in real time. Dielectrophoretically tunable optofluidic devices offer several attractive features, such as rapid prototyping, miniaturization, easy integration and low power consumption. In this review paper, we first explain the underlying operation principles and then review some recent progress in this field, covering the topics of adaptive lens, beam steering, iris, grating, optical switch/attenuator and single pixel display. Finally, the future perspectives are discussed.

  1. Thermoelectric materials and devices

    Science.gov (United States)

    Park, Yeonjoon (Inventor); Choi, Sang H. (Inventor); King, Glen C. (Inventor); Elliott, James R. (Inventor); Talcott, Noel A. (Inventor)

    2011-01-01

    New thermoelectric materials comprise highly [111]-oriented twinned group IV alloys on the basal plane of trigonal substrates, which exhibit a high thermoelectric figure of merit and good material performance, and devices made with these materials.

  2. Geometry and Cloaking Devices

    Science.gov (United States)

    Ochiai, T.; Nacher, J. C.

    2011-09-01

    Recently, the application of geometry and conformal mappings to artificial materials (metamaterials) has attracted the attention in various research communities. These materials, characterized by a unique man-made structure, have unusual optical properties, which materials found in nature do not exhibit. By applying the geometry and conformal mappings theory to metamaterial science, it may be possible to realize so-called "Harry Potter cloaking device". Although such a device is still in the science fiction realm, several works have shown that by using such metamaterials it may be possible to control the direction of the electromagnetic field at will. We could then make an object hidden inside of a cloaking device. Here, we will explain how to design invisibility device using differential geometry and conformal mappings.

  3. Authenticated sensor interface device

    Energy Technology Data Exchange (ETDEWEB)

    Coleman, Jody Rustyn; Poland, Richard W.

    2016-10-18

    A system and method for the secure storage and transmission of data is provided. A data aggregate device can be configured to receive secure data from a data source, such as a sensor, and encrypt the secure data using a suitable encryption technique, such as a shared private key technique, a public key encryption technique, a Diffie-Hellman key exchange technique, or other suitable encryption technique. The encrypted secure data can be provided from the data aggregate device to different remote devices over a plurality of segregated or isolated data paths. Each of the isolated data paths can include an optoisolator that is configured to provide one-way transmission of the encrypted secure data from the data aggregate device over the isolated data path. External data can be received through a secure data filter which, by validating the external data, allows for key exchange and other various adjustments from an external source.

  4. Halo traction device.

    Science.gov (United States)

    Manthey, D E

    1994-08-01

    A thorough understanding of the underlying diseases and of the halo pin traction device will allow for appropriate treatment of complications. Consultation or referral to the neurosurgeon is advised to prevent serious sequelae. The following points should be remembered: 1. Pins should only be tightened during the first 24-hour period after application. 2. Pin infection is treated by local wound care in most cases. 3. CT scan cannot completely exclude the presence of an abscess secondary to artifact, but MRI may be compatible with the newer devices. 4. Pin penetration of the inner table of the skull requires admission. 5. Any suspected loss of alignment or reduction of the cervical spine requires C-spine immobilization. 5. Nasotracheal or fiberoptic intubation or emergent cricothyroidotomy should be used if orotracheal intubation proves difficult due to the device. 7. The anterior portion of the vest is removable for cardiopulmonary resuscitation without compromising the stability of the device. PMID:8062799

  5. MDR (Medical Device Reporting)

    Data.gov (United States)

    U.S. Department of Health & Human Services — This database allows you to search the CDRH's database information on medical devices which may have malfunctioned or caused a death or serious injury during the...

  6. Resources: Handheld Computing Devices

    OpenAIRE

    Denson, Cameron

    2008-01-01

    The article features a valuable resource to aid teachers in their effort to satisfy the need to implement modern instructional technology and their students' need to access green technology. It states that handheld computing devices are currently being widely used in many classrooms and technology savvy educators can manifest to the benefits of these data-collection systems. It believes that handheld units can offer students with an all-inclusive technological device that caters to all learners.

  7. Nanoplasmonics advanced device applications

    CERN Document Server

    Chon, James W M

    2013-01-01

    Focusing on control and manipulation of plasmons at nanometer dimensions, nanoplasmonics combines the strength of electronics and photonics, and is predicted to replace existing integrated circuits and photonic devices. It is one of the fastest growing fields of science, with applications in telecommunication, consumer electronics, data storage, medical diagnostics, and energy.Nanoplasmonics: Advanced Device Applications provides a scientific and technological background of a particular nanoplasmonic application and outlines the progress and challenges of the application. It reviews the latest

  8. Inverted organic photosensitive device

    Energy Technology Data Exchange (ETDEWEB)

    Forrest, Stephen R.; Tong, Xiaoran; Lee, Jun Yeob; Cho, Yong Joo

    2015-09-08

    There is disclosed a method for preparing the surface of a metal substrate. The present disclosure also relates to an organic photovoltaic device including a metal substrate made by such method. Also disclosed herein is an inverted photosensitive device including a stainless steel foil reflective electrode, an organic donor-acceptor heterojunction over the reflective electrode, and a transparent electrode over the donor-acceptor heterojunction.

  9. Holographic liquid crystal devices

    OpenAIRE

    Pavani, Kotakonda, (Thesis)

    2009-01-01

    Liquid crystals have become natural candidates for use in electro-optic devices for their ability to change the orientation of the director with the application of an electric field, and exhibiting large range of refractive index. The aim of the work presented in this thesis is to fabricate liquid crystal optoelectronic devices such as electrically switchable liquid crystal diffraction gratings and polarization rotators by exploiting the holographic surface relief effect in photopolymer and b...

  10. Projection and registration device

    OpenAIRE

    Verlinden, J.C.

    2009-01-01

    A projection and recording device, provided with a processing and control unit, a memory for recording images and other data, an input/output interface, a controllable camera, a touch screen for the input and display of data and images, a position determining system for determining the position of at least one object in relation to the projection and recording device, with images recorded by the camera being storable in the memory and displayable on the touch screen, and a projector for proje...

  11. Electronic security device

    International Nuclear Information System (INIS)

    The present invention relates to a security device having a control box containing an electronic system and a communications loop over which the system transmits a signal. The device is constructed so that the communications loop can extend from the control box across the boundary of a portal such as a door into a sealed enclosure into which access is restricted whereby the loop must be damaged or moved in order for an entry to be made into the enclosure. The device is adapted for detecting unauthorized entries into such enclosures such as rooms or containers and for recording the time at which such entries occur for later reference. Additionally, the device detects attempts to tamper or interfere with the operation of the device itself and records the time at which such events take place. In the preferred embodiment, the security device includes a microprocessor-based electronic system and a detection module capable of registering changes in the voltage and phase of the signal transmitted over the loop. 11 figs

  12. Synthetic nanoscale motion devices

    Energy Technology Data Exchange (ETDEWEB)

    Lyshevski, M.A. [Microsystems and Nanotechnologies, Webster, NY (United States); Lyshevski, S.E. [Rochester Inst. of Technology, Rochester, NY (United States). Dept. of Electrical Engineering

    2007-07-01

    This study examined biomolecular axial and radial topology rotational machines, as well as translational motion devices made from proteins. In particular, it documented the integrated topological, structural and analytic design of synthetic nanoscale motion devices in an effort to promote high performance and meet specifications. Control, analysis and design problems were solved for electromagnetic motion devices. A systematic synthesis resulted in a radial topology permanent-magnetic device with noncontact electrostatic bearings for use in microrobotics. Such nanoscale motion devices can be made from carbon nanotubes using molecular nanotechnology and surface chemistry. Structures, magnets and windings were formed by depositing polymers and organic/inorganic molecules on the noncontact electrostatic bearings. The electromagnetic torque was studied to analyze the electromagnetics and nonuniform field. The electromagnetic torque was varied in order to control the phase voltages applied to the windings. The closed-loop systems were designed for stability, controllability and optimal performance. The proposed machines can be used as nanoscale generators to convert mechanical energy into electrical energy. The permanent-magnet synthetic motion devices may have practical use in nano- and micro robots, assemblers and propulsors. Practical control laws were derived from electromagnetic and electromechanical analyses. 5 refs., 3 figs.

  13. Alternative Devices for Taking Insulin

    Science.gov (United States)

    ... KB). Alternate Language URL Alternative Devices for Taking Insulin Page Content On this page: What alternative devices ... the skin. [ Top ] What alternative devices for taking insulin are available? Insulin pens provide a convenient, easy- ...

  14. Cataphoric devices in spoken discourse.

    Science.gov (United States)

    Gernsbacher, M A; Jescheniak, J D

    1995-08-01

    We propose that speakers mark key words with cataphoric devices. Cataphoric devices are counterparts to anaphoric devices: Just as anaphoric devices enable backward reference, cataphoric devices enable forward reference. And just as anaphoric devices mark concepts that have been mentioned before, cataphoric devices mark concepts that are likely to be mentioned again. We investigated two cataphoric devices: spoken stress and the indefinite this. Our experiments demonstrated three ways that concepts marked by cataphoric devices gain a privileged status in listeners' mental representations: Cataphoric devices enhance the activation of the concepts that they mark; cataphoric devices suppress the activation of previously mentioned concepts; and cataphoric devices protect the concepts that they mark from being suppressed by subsequently mentioned concepts. PMID:7641525

  15. Diamond Electronic Devices

    Science.gov (United States)

    Isberg, J.

    2010-11-01

    For high-power and high-voltage applications, silicon is by far the dominant semiconductor material. However, silicon has many limitations, e.g. a relatively low thermal conductivity, electric breakdown occurs at relatively low fields and the bandgap is 1.1 eV which effectively limits operation to temperatures below 175° C. Wide-bandgap materials, such as silicon carbide (SiC), gallium nitride (GaN) and diamond offer the potential to overcome both the temperature and power handling limitations of silicon. Diamond is the most extreme in this class of materials. By the fundamental material properties alone, diamond offers the largest benefits as a semiconductor material for power electronic applications. On the other hand, diamond has a problem with a large carrier activation energy of available dopants which necessitates specialised device concepts to allow room temperature (RT) operation. In addition, the role of common defects on the charge transport properties of diamond is poorly understood. Notwithstanding this, many proof-of-principle two-terminal and three-terminal devices have been made and tested. Two-terminal electronic diamond devices described in the literature include: p-n diodes, p-i-n diodes, various types of radiation detectors, Schottky diodes and photoconductive or electron beam triggered switches. Three terminal devices include e.g. MISFETs and JFETs. However, the development of diamond devices poses great challenges for the future. A particularly interesting way to overcome the doping problem, for which there has been some recent progress, is to make so-called delta doped (or pulse-doped) devices. Such devices utilise very thin (˜1 nm) doped layers in order to achieve high RT activation.

  16. Diamond Electronic Devices

    International Nuclear Information System (INIS)

    For high-power and high-voltage applications, silicon is by far the dominant semiconductor material. However, silicon has many limitations, e.g. a relatively low thermal conductivity, electric breakdown occurs at relatively low fields and the bandgap is 1.1 eV which effectively limits operation to temperatures below 175 deg.n C. Wide-bandgap materials, such as silicon carbide (SiC), gallium nitride (GaN) and diamond offer the potential to overcome both the temperature and power handling limitations of silicon. Diamond is the most extreme in this class of materials. By the fundamental material properties alone, diamond offers the largest benefits as a semiconductor material for power electronic applications. On the other hand, diamond has a problem with a large carrier activation energy of available dopants which necessitates specialised device concepts to allow room temperature (RT) operation. In addition, the role of common defects on the charge transport properties of diamond is poorly understood. Notwithstanding this, many proof-of-principle two-terminal and three-terminal devices have been made and tested. Two-terminal electronic diamond devices described in the literature include: p-n diodes, p-i-n diodes, various types of radiation detectors, Schottky diodes and photoconductive or electron beam triggered switches. Three terminal devices include e.g. MISFETs and JFETs. However, the development of diamond devices poses great challenges for the future. A particularly interesting way to overcome the doping problem, for which there has been some recent progress, is to make so-called delta doped (or pulse-doped) devices. Such devices utilise very thin (∼1 nm) doped layers in order to achieve high RT activation.

  17. Physics of semiconductor devices

    CERN Document Server

    Rudan, Massimo

    2015-01-01

    This book describes the basic physics of semiconductors, including the hierarchy of transport models, and connects the theory with the functioning of actual semiconductor devices.  Details are worked out carefully and derived from the basic physics, while keeping the internal coherence of the concepts and explaining various levels of approximation. Examples are based on silicon due to its industrial importance. Several chapters are included that provide the reader with the quantum-mechanical concepts necessary for understanding the transport properties of crystals. The behavior of crystals incorporating a position-dependent impurity distribution is described, and the different hierarchical transport models for semiconductor devices are derived (from the Boltzmann transport equation to the hydrodynamic and drift-diffusion models). The transport models are then applied to a detailed description of the main semiconductor-device architectures (bipolar, MOS). The final chapters are devoted to the description of s...

  18. Condensate filtering device

    International Nuclear Information System (INIS)

    In a condensate filtering device of a nuclear power plant, a water collecting pipe is disposed over the entire length, an end of a hollow thread is in communication with the water collecting pipe and secured. If the length of the water collecting pipe is extended, a filtering device of an optional length can be obtained irrespective of the length of the hollow thread. Therefore, since there is no need to connect units upon constituting a module, flow of cleaning gases is not restricted at connection portions. Accordingly, even if the volume of the device is increased by the extension of the module, the working life of the module is not degraded. (T.M.)

  19. Pendulum detector testing device

    International Nuclear Information System (INIS)

    A detector testing device is described which provides consistent, cost-effective, repeatable results. The testing device is primarily constructed of PVC plastic and other non-metallic materials. Sensitivity of a walk-through detector system can be checked by: (1) providing a standard test object simulating the mass, size and material content of a weapon or other contraband, (2) suspending the test object in successive positions, such as head, waist and ankle levels, simulating where the contraband might be concealed on a person walking through the detector system; and (3) swinging the suspended object through each of the positions, while operating the detector system and observing its response. The test object is retained in a holder in which the orientation of the test device or target can be readily changed, to properly complete the testing requirements. 5 figs

  20. Ion manipulation device

    Science.gov (United States)

    Anderson, Gordon A; Smith, Richard D; Ibrahim, Yehia M; Baker, Erin M

    2014-09-16

    An ion manipulation method and device is disclosed. The device includes a pair of substantially parallel surfaces. An array of inner electrodes is contained within, and extends substantially along the length of, each parallel surface. The device includes a first outer array of electrodes and a second outer array of electrodes. Each outer array of electrodes is positioned on either side of the inner electrodes, and is contained within and extends substantially along the length of each parallel surface. A DC voltage is applied to the first and second outer array of electrodes. A RF voltage, with a superimposed electric field, is applied to the inner electrodes by applying the DC voltages to each electrode. Ions either move between the parallel surfaces within an ion confinement area or along paths in the direction of the electric field, or can be trapped in the ion confinement area.

  1. ALS insertion devices

    International Nuclear Information System (INIS)

    The Advanced Light Source (ALS), the first US third generation synchrotron radiation source, is currently under construction at the Lawrence Berkeley Laboratory. The low-emittance, 1.5 GeV electron storage ring and the insertion devices are specifically designed to produce high brightness beams in the UV to soft X-Ray range. The planned initial complement of insertion devices includes four 4.6 m long undulators, with period lengths of 3.9 cm, 5.0 cm (2) and 8.0 cm, and a 2.9 m long wiggler of 16 cm period length. Undulator design is well advanced and fabrication has begun on the 5.0 cm and 8.0 cm period length undulators. This paper discusses ALS insertion device requirements; general design philosophy; and design of the magnetic structure, support structure/drive systems, control system and vacuum system. 18 refs., 9 figs., 5 tabs

  2. Evolution of Growth Hormone Devices: Matching Devices with Patients.

    Science.gov (United States)

    Raimer-Hall, Dawn; Shea, Heidi Chamberlain

    2015-01-01

    Self-injection of growth hormone (GH) by children with GH deficiency can be problematic. They may have difficulty manipulating injection devices or preparing medication, and injections can be painful and create anxiety. Adherence to daily GH injections optimizes treatment benefit. Studies indicate that injection pens or needle-free devices enable easy self-injection by children, minimize medication reconstitution and storage requirements, and reduce injection pain. Newer GH delivery devices potentially encourage improved patient adherence. Reviewing features of GH devices will help nurses decide which GH device best fits the needs and abilities of pediatric patients. We searched recent medical literature about GH device development, about device-associated patient preferences and treatment adherence, and comparisons among GH devices. We concluded that improved awareness of the strengths and limitations of GH devices will enable nurses to guide families in selecting and using GH devices, improving adherence and outcomes, and helping children reach full growth potential. PMID:26292454

  3. Electronic devices and circuits

    CERN Document Server

    Pridham, Gordon John

    1968-01-01

    Electronic Devices and Circuits, Volume 1 deals with the design and applications of electronic devices and circuits such as passive components, diodes, triodes and transistors, rectification and power supplies, amplifying circuits, electronic instruments, and oscillators. These topics are supported with introductory network theory and physics. This volume is comprised of nine chapters and begins by explaining the operation of resistive, inductive, and capacitive elements in direct and alternating current circuits. The theory for some of the expressions quoted in later chapters is presented. Th

  4. Nanoelectromechanics of shuttle devices

    Science.gov (United States)

    Shekhter, R. I.; Gorelik, L. Y.; Krive, I. V.; Kiselev, M. N.; Parafilo, A. V.; Jonson, M.

    2013-04-01

    A single-electron tunneling (SET) device with a nanoscale central island that can move with respect to the bulk sourceand drain electrodes allows for a nanoelectromechanical (NEM) coupling between the electrical current through the device and the mechanical vibrations of the island. Although the electromechanical "shuttle" instability and the associated phenomenon of single-electron shuttling were predicted more than 15 years ago, both theoretical and experimental studies of NEM-SET structures are still carried out. New functionalities based on quantum coherence, Coulomb correlations and coherent electron-spin dynamics are still of particular interest. In this article we present a short review of recent activities in this area.

  5. Asphaltene based photovoltaic devices

    Science.gov (United States)

    Chianelli, Russell R.; Castillo, Karina; Gupta, Vipin; Qudah, Ali M.; Torres, Brenda; Abujnah, Rajib E.

    2016-03-22

    Photovoltaic devices and methods of making the same, are disclosed herein. The cell comprises a photovoltaic device that comprises a first electrically conductive layer comprising a photo-sensitized electrode; at least one photoelectrochemical layer comprising metal-oxide particles, an electrolyte solution comprising at least one asphaltene fraction, wherein the metal-oxide particles are optionally dispersed in a surfactant; and a second electrically conductive layer comprising a counter-electrode, wherein the second electrically conductive layer comprises one or more conductive elements comprising carbon, graphite, soot, carbon allotropes or any combinations thereof.

  6. Nanoscale memory devices

    International Nuclear Information System (INIS)

    This article reviews the current status and future prospects for the use of nanomaterials and devices in memory technology. First, the status and continuing scaling trends of the flash memory are discussed. Then, a detailed discussion on technologies trying to replace flash in the near-term is provided. This includes phase change random access memory, Fe random access memory and magnetic random access memory. The long-term nanotechnology prospects for memory devices include carbon-nanotube-based memory, molecular electronics and memristors based on resistive materials such as TiO2. (topical review)

  7. INLET STRATIFICATION DEVICE

    DEFF Research Database (Denmark)

    2006-01-01

    An inlet stratification device (5) for a circuit circulating a fluid through a tank (1 ) and for providing and maintaining stratification of the fluid in the tank (1 ). The stratification de- vice (5) is arranged vertically in the tank (1) and comprises an inlet pipe (6) being at least partially...... formed of a flexible porous material and having an inlet (19) and outlets formed of the pores of the porous material. The stratification device (5) further comprises at least one outer pipe (7) surrounding the inlet pipe (6) in spaced relationship thereto and being at least partially formed of a porous...

  8. Microfluidic Cell Culture Device

    Science.gov (United States)

    Takayama, Shuichi (Inventor); Cabrera, Lourdes Marcella (Inventor); Heo, Yun Seok (Inventor); Smith, Gary Daniel (Inventor)

    2014-01-01

    Microfluidic devices for cell culturing and methods for using the same are disclosed. One device includes a substrate and membrane. The substrate includes a reservoir in fluid communication with a passage. A bio-compatible fluid may be added to the reservoir and passage. The reservoir is configured to receive and retain at least a portion of a cell mass. The membrane acts as a barrier to evaporation of the bio-compatible fluid from the passage. A cover fluid may be added to cover the bio-compatible fluid to prevent evaporation of the bio-compatible fluid.

  9. Preventing medical device recalls

    CERN Document Server

    Raheja, Dev

    2014-01-01

    Introduction to Medical Device RequirementsIntroductionThe ChallengesSources of ErrorsUnderstanding the Science of Safety     Overview of FDA Quality System Regulation     Overview of Risk Management Standard ISO 14971     Overview of FDA Device Approval Process     Overview of Regulatory Requirements for Clinical TrialsSummaryReferencesPreventing Recalls during Specification WritingIntroductionConduct Requirements Analysis to Identify Missing RequirementsSpecifications for Safety, Durability, and

  10. Microwave Magnetoelectric Devices

    OpenAIRE

    Tatarenko, A. S.; Bichurin, M. I.

    2012-01-01

    Tunable microwave magnetoelectric devices based on layered ferrite-ferroelectric structures are described. The theory and experiment for attenuator, band-pass filter and phase shifter are presented. Tunability of the ME devices characteristics can be executed by application of an electric field. This electric tuning is relatively fast and is not power-consuming. The attenuator insertion losses vary from 26 dB to 2 dB at frequency 7251 MHz. The tuning range of 25 MHz of band-pass filter at fre...

  11. Graphene field emission devices

    OpenAIRE

    DUESBERG, GEORG

    2014-01-01

    PUBLISHED Graphene field emission devices are fabricated using a scalable process. The field enhancement factors, determined from the Fowler-Nordheim plots, are within few hundreds and match the theoretical predictions. The devices show high emission current density of ∼10 nA μm−1 at modest voltages of tens of volts. The emission is stable with time and repeatable over long term, whereas the noise in the emission current is comparable to that from individual carbon nanotubes emitting under...

  12. Phononic crystal devices

    Science.gov (United States)

    El-Kady, Ihab F.; Olsson, Roy H.

    2012-01-10

    Phononic crystals that have the ability to modify and control the thermal black body phonon distribution and the phonon component of heat transport in a solid. In particular, the thermal conductivity and heat capacity can be modified by altering the phonon density of states in a phononic crystal. The present invention is directed to phononic crystal devices and materials such as radio frequency (RF) tags powered from ambient heat, dielectrics with extremely low thermal conductivity, thermoelectric materials with a higher ratio of electrical-to-thermal conductivity, materials with phononically engineered heat capacity, phononic crystal waveguides that enable accelerated cooling, and a variety of low temperature application devices.

  13. Device configuration-management system

    International Nuclear Information System (INIS)

    The Fusion Chamber System, a major component of the Magnetic Fusion Test Facility, contains several hundred devices which report status to the Supervisory Control and Diagnostic System for control and monitoring purposes. To manage the large number of diversity of devices represented, a device configuration management system was required and developed. Key components of this software tool include the MFTF Data Base; a configuration editor; and a tree structure defining the relationships between the subsystem devices. This paper will describe how the configuration system easily accomodates recognizing new devices, restructuring existing devices, and modifying device profile information

  14. Nano devices and sensors

    CERN Document Server

    Liaw, Shien-Kuei; Chung, Yung-Hui

    2016-01-01

    This volume on semiconductor devices focuses on such topics as nano-imprinting, lithography, nanowire charge-trapping, thermo-stability in nanowires, nano-electrodes, and voltage and materials used for fabricating and improving electrical characteristics of nano-materials.

  15. Container Monitoring Device (case)

    NARCIS (Netherlands)

    Maas, A.; Ruijsbroek, W.G.J.

    2015-01-01

    Stage Gate 11 is een bedrijf dat technologische innovaties naar de markt brengt. De drie ondernemers hebben een nieuw product ontwikkeld, de Container Monitoring Device, een product dat stalen containers ‘smart’ maakt door er allerlei sensoren aan te koppelen. Maar waar ligt precies de toegevoegde w

  16. Devic's Disease (Neuromyelitis optical)

    International Nuclear Information System (INIS)

    We present a case report about a young woman initially treated as having multiple sclerosis, who relapsed with serious visual impairment. Devic's disease is a demyelinating disorder that presents as transverse myelitis associated with optic neuritis, typically bilateral. Multiple sclerosis is in fact the main differential diagnosis

  17. Inlet stratification device

    DEFF Research Database (Denmark)

    2014-01-01

    An inlet stratification (5) is adapted to be arranged vertically in a tank (1) during operation. The stratification device (5) comprises an inlet pipe (6) formed of a flexible porous material and having a lower and upper end. The lower end of the inlet pipe (6) is connected to a bottom cap (10...

  18. Surface Acoustic Wave Devices

    DEFF Research Database (Denmark)

    Dühring, Maria Bayard

    The work of this project is concerned with the simulation of surface acoustic waves (SAW) and topology optimization of SAW devices. SAWs are elastic vibrations that propagate along a material surface and are extensively used in electromechanical filters and resonators in telecommunication. A new...

  19. Road-Cleaning Device

    Science.gov (United States)

    Roman, Harry T.

    2014-01-01

    Roadways are literally soaked with petrochemical byproducts, oils, gasoline, and other volatile substances that eventually run off into sewers and end up in rivers, waterways, and other undesirable places. Can the roads be cleaned of these wastes, with their proper disposal? Can vehicles, robots, or other devices be designed that could be driven…

  20. Optical switching device

    NARCIS (Netherlands)

    Broeder, F.J.A. den; Hanzen, R.M.N.; Duine, P.A.; Jungblut, R.M.; Draijer, C.; Roozeboom, F.; Sluis, P. van der

    2000-01-01

    A description is given of an optical switching device (1) comprising a transparent substrate (3), a switching film (5) of a hydride compound of a trivalent transition or rare earth metal having a thickness of 300 nm, and a palladium capping layer (7) having a thickness of 30 nm. The capping layer is

  1. Spark ablation device

    NARCIS (Netherlands)

    Schmidt-Ott, A.; Pfeiffer, T.V.

    2013-01-01

    A spark ablation device for generating nanoparticles comprising a spark generator; the spark generator comprising first and second electrodes, wherein the spark generator further comprises at least one power source which is arranged to be operative at a first energy level for maintaining a discharge

  2. Air Stable Photovoltaic Device

    DEFF Research Database (Denmark)

    2010-01-01

    A method of forming a conducting polymer based photovoltaic device comprising the steps of : (a) providing a transparent first electrode; (b) providing the transparent first electrode with a layer of metal oxide nanoparticles, wherein the metal oxide is selected from the group consisting of : TiO...

  3. The missing intrauterine device

    Directory of Open Access Journals (Sweden)

    Rajesh Devassy

    2016-10-01

    Full Text Available The Intrauterine Contraceptive Device (IUD is an acceptable and common form of contraception worldwide. The objective of this study was to report the case of an asymptomatic missing intrauterine contraceptive (IUD inserted to prevent intrauterine adhesions after synechiolysis. A patient presented with missing IUD threads. Ultrasound of the pelvis showed an empty uterine cavity with the missing IUD probably anterior to the uterus. We present a stepwise approach in the management of the and ldquo;lost IUD and rdquo;, where the strings of the device are not visible at the time of speculum examination. We suggest first determining sonographically whether the IUD is within the cavity. If it is in situ, options for retrieval are including hysteroscopic retrieval. If the IUD is not within the cavity, X-rays are recommended. The device will not be present on X-ray if expulsion has occurred. If the device is present on the X-ray, cystoscopic or laparoscopic retrieval is required. IUD-providers should not only screen potential users and insert IUD correctly, but also ensure adequate follow-up with localization. [Int J Reprod Contracept Obstet Gynecol 2016; 5(10.000: 3587-3589

  4. Device Oriented Project Controller

    Energy Technology Data Exchange (ETDEWEB)

    Dalesio, Leo; Kraimer, Martin

    2013-11-20

    This proposal is directed at the issue of developing control systems for very large HEP projects. A de-facto standard in accelerator control is the Experimental Physics and Industrial Control System (EPICS), which has been applied successfully to many physics projects. EPICS is a channel based system that requires that each channel of each device be configured and controlled. In Phase I, the feasibility of a device oriented extension to the distributed channel database was demonstrated by prototyping a device aware version of an EPICS I/O controller that functions with the current version of the channel access communication protocol. Extensions have been made to the grammar to define the database. Only a multi-stage position controller with limit switches was developed in the demonstration, but the grammar should support a full range of functional record types. In phase II, a full set of record types will be developed to support all existing record types, a set of process control functions for closed loop control, and support for experimental beam line control. A tool to configure these records will be developed. A communication protocol will be developed or extensions will be made to Channel Access to support introspection of components of a device. Performance bench marks will be made on both communication protocol and the database. After these records and performance tests are under way, a second of the grammar will be undertaken.

  5. Wavelength conversion devices

    DEFF Research Database (Denmark)

    Mikkelsen, Benny; Durhuus, Terji; Jørgensen, Carsten;

    1996-01-01

    Summary form only given. Wavelength converters will be essential devices to exploit the full potential of the wavelength dimension in wavelength-division multiplexed (WDM) networks. Based on experiments, we discuss different candidates for efficient wavelength converters with attention to expected...

  6. Underwater running device

    International Nuclear Information System (INIS)

    An underwater running device for an underwater inspection device for detecting inner surfaces of a reactor or a water vessel has an outer frame and an inner frame, and both of them are connected slidably by an air cylinder and connected rotatably by a shaft. The outer frame has four outer frame legs, and each of the outer frame legs is equipped with a sucker at the top end. The inner frame has four inner frame legs each equipped with a sucker at the top end. The outer frame legs and the inner frame legs are each connected with the outer frame and the inner frame by the air cylinder. The outer and the inner frame legs can be elevated or lowered (or extended or contracted) by the air cylinder. The sucker is connected with a jet pump-type negative pressure generator. The device can run and move by repeating attraction and releasing of the outer frame legs and the inner frame legs alternately while maintaining the posture of the inspection device stably. (I.N.)

  7. A Medical Delivery Device

    DEFF Research Database (Denmark)

    2010-01-01

    The present invention relates to a medical delivery device comprising at least two membrane electrode assembly units each of which comprises three layers: an upper and a lower electrode and a selective ionic conductive membrane provided there-between. At least one of the three layers are shared...

  8. Cybersecurity for Connected Diabetes Devices

    OpenAIRE

    Klonoff, David C.

    2015-01-01

    Diabetes devices are increasingly connected wirelessly to each other and to data-displaying reader devices. Threats to the accurate flow of information and commands may compromise the function of these devices and put their users at risk of health complications. Sound cybersecurity of connected diabetes devices is necessary to maintain confidentiality, integrity, and availability of the data and commands. Diabetes devices can be hacked by unauthorized agents and also by patients themselves to...

  9. Medical device regulation for manufacturers.

    Science.gov (United States)

    McAllister, P; Jeswiet, J

    2003-01-01

    Manufacturers of medical devices are held to a higher standard than manufacturers of many other products due to the potential severity of the consequences of introducing inferior or unsafe products to the market-place. In Canada, the medical device industry is regulated by Health Canada under the Medical Device Regulations of the Food and Drug Act. The Medical Device Regulations define requirements of medical device design, development and manufacture to ensure that products reaching the public are safe and effective. Health Canada also requires that medical device manufacturers maintain distribution records to ensure that devices can be traced to the source and consumers can be contacted successfully in the event that a device is recalled. Medical devices exported from Canada must be compliant with the regulations of the country of import. The Canadian Medical Device Regulations were based on the Medical Device Directives of the European Union thus facilitating approval of Canadian devices for the European market. The United States Food and Drug Administration has separate and distinct requirements for safety and quality of medical devices. While effort has been made to facilitate approval and trade of Canadian medical devices in the United States and the European Union, obtaining approval from multiple regulatory bodies can result in increased device development time and cost. The Global Harmonization Task Force is an organization composed of members from Japanese, Australian, European, Canadian and American medical device regulatory bodies. This organization was formed with the objective of harmonizing medical device regulations in an effort to facilitate international trade and standardize the quality of medical devices available to all countries. This paper discusses the requirements that must be met by manufacturers when designing and manufacturing medical devices.

  10. Microelectromechanical reprogrammable logic device

    KAUST Repository

    Hafiz, M. A. A.

    2016-03-29

    In modern computing, the Boolean logic operations are set by interconnect schemes between the transistors. As the miniaturization in the component level to enhance the computational power is rapidly approaching physical limits, alternative computing methods are vigorously pursued. One of the desired aspects in the future computing approaches is the provision for hardware reconfigurability at run time to allow enhanced functionality. Here we demonstrate a reprogrammable logic device based on the electrothermal frequency modulation scheme of a single microelectromechanical resonator, capable of performing all the fundamental 2-bit logic functions as well as n-bit logic operations. Logic functions are performed by actively tuning the linear resonance frequency of the resonator operated at room temperature and under modest vacuum conditions, reprogrammable by the a.c.-driving frequency. The device is fabricated using complementary metal oxide semiconductor compatible mass fabrication process, suitable for on-chip integration, and promises an alternative electromechanical computing scheme.

  11. Thin film device applications

    CERN Document Server

    Kaur, Inderjeet

    1983-01-01

    Two-dimensional materials created ab initio by the process of condensation of atoms, molecules, or ions, called thin films, have unique properties significantly different from the corresponding bulk materials as a result of their physical dimensions, geometry, nonequilibrium microstructure, and metallurgy. Further, these characteristic features of thin films can be drasti­ cally modified and tailored to obtain the desired and required physical characteristics. These features form the basis of development of a host of extraordinary active and passive thin film device applications in the last two decades. On the one extreme, these applications are in the submicron dimensions in such areas as very large scale integration (VLSI), Josephson junction quantum interference devices, magnetic bubbles, and integrated optics. On the other extreme, large-area thin films are being used as selective coatings for solar thermal conversion, solar cells for photovoltaic conver­ sion, and protection and passivating layers. Ind...

  12. Device for crushing rocks

    Energy Technology Data Exchange (ETDEWEB)

    Kanygin, A.S.; Bulavtsev, V.A.; Zhidkov, A.V.

    1984-01-01

    The purpose of the invention is to simplify the design. The device includes a hydrocylinder with main piston and rod, additional piston with rod placed in the cavity of the main piston rod, wedge attached to the additional piston rod, extension jaws attached to the hydrocylinder housing, and attachment for supply of the working fluid into the above-piston cavity of the rod in the main piston. The latter is made in the form of a channel with reverse valve which connects the rod cavity of the hydrocylinder to the above-piston cavity of the main piston rod. The reverse valve is in the main piston and is made with push rod which goes beyond the limits of the piston on the side of the hydrocylinder rod cavity. The device is designed to separate blocks from the massif on the borehole line.

  13. Anti-gravity device

    Science.gov (United States)

    Palsingh, S. (Inventor)

    1975-01-01

    An educational toy useful in demonstrating fundamental concepts regarding the laws of gravity is described. The device comprises a sphere 10 of radius r resting on top of sphere 12 of radius R. The center of gravity of sphere 10 is displaced from its geometrical center by distance D. The dimensions are so related that D((R+r)/r) is greater than r. With the center of gravity of sphere 10 lying on a vertical line, the device is in equilibrium. When sphere 10 is rolled on the surface of sphere 12 it will return to its equilibrium position upon release. This creates an illusion that sphere 10 is defying the laws of gravity. In reality, due to the above noted relationship of D, R, and r, the center of gravity of sphere 10 rises from its equilibrium position as it rolls a short distance up or down the surface of sphere 12.

  14. Organic photosensitive devices

    Science.gov (United States)

    Peumans, Peter; Forrest, Stephen R.

    2013-01-22

    A photoactive device is provided. The device includes a first electrode, a second electrode, and a photoactive region disposed between and electrically connected to the first and second electrodes. The photoactive region further includes an organic donor layer and an organic acceptor layer that form a donor-acceptor heterojunction. The mobility of holes in the organic donor region and the mobility of electrons in the organic acceptor region are different by a factor of at least 100, and more preferably a factor of at least 1000. At least one of the mobility of holes in the organic donor region and the mobility of electrons in the organic acceptor region is greater than 0.001 cm.sup.2/V-sec, and more preferably greater than 1 cm.sup.2/V-sec. The heterojunction may be of various types, including a planar heterojunction, a bulk heterojunction, a mixed heterojunction, and a hybrid planar-mixed heterojunction.

  15. Integrated elastic microscope device

    Science.gov (United States)

    Lee, W. M.; Wright, D.; Watkins, R.; Cen, Zi

    2015-03-01

    The growing power of imaging and computing power of smartphones is creating the possibility of converting your smartphone into a high power pocket microscopy system. High quality miniature microscopy lenses attached to smartphone are typically made with glass or plastics that can only be produce at low cost with high volume. To revise the paradigm of microscope lenses, we devised a simple droplet lens fabrication technique that which produces low cost and high performance lens. Each lens is integrated into thin 3-D printed holder with complimentary light emitted diode (LEDs) that clips onto majority of smartphones. The integrated device converts a smartphone into a high power optical microscope/dermatoscope at around $2. This low cost device has wide application in a multitude of practical uses such as material inspection, dermascope and educational microscope.

  16. Microwave Magnetoelectric Devices

    Directory of Open Access Journals (Sweden)

    A. S. Tatarenko

    2012-01-01

    Full Text Available Tunable microwave magnetoelectric devices based on layered ferrite-ferroelectric structures are described. The theory and experiment for attenuator, band-pass filter and phase shifter are presented. Tunability of the ME devices characteristics can be executed by application of an electric field. This electric tuning is relatively fast and is not power-consuming. The attenuator insertion losses vary from 26 dB to 2 dB at frequency 7251 MHz. The tuning range of 25 MHz of band-pass filter at frequency 7360 MHz was obtained. A maximum phase shift of 30–40 degree at the frequency region 6–9 GHz was obtained.

  17. Particle capture device

    Energy Technology Data Exchange (ETDEWEB)

    Jayne, John T.; Worsnop, Douglas R.

    2016-02-23

    In example embodiments, particle collection efficiency in aerosol analyzers and other particle measuring instruments is improved by a particle capture device that employs multiple collisions to decrease momentum of particles until the particles are collected (e.g., vaporized or come to rest). The particle collection device includes an aperture through which a focused particle beam enters. A collection enclosure is coupled to the aperture and has one or more internal surfaces against which particles of the focused beam collide. One or more features are employed in the collection enclosure to promote particles to collide multiple times within the enclosure, and thereby be vaporized or come to rest, rather than escape through the aperture.

  18. Dielectrokinetic chromatography devices

    Science.gov (United States)

    Chirica, Gabriela S; Fiechtner, Gregory J; Singh, Anup K

    2014-12-16

    Disclosed herein are methods and devices for dielectrokinetic chromatography. As disclosed, the devices comprise microchannels having at least one perturber which produces a non-uniformity in a field spanning the width of the microchannel. The interaction of the field non-uniformity with a perturber produces a secondary flow which competes with a primary flow. By decreasing the size of the perturber the secondary flow becomes significant for particles/analytes in the nanometer-size range. Depending on the nature of a particle/analyte present in the fluid and its interaction with the primary flow and the secondary flow, the analyte may be retained or redirected. The composition of the primary flow can be varied to affect the magnitude of primary and/or secondary flows on the particles/analytes and thereby separate and concentrate it from other particles/analytes.

  19. Electronic devices and circuits

    CERN Document Server

    Kishore, K Lal

    2008-01-01

    This book is written in a simple lucid Language along with derivation of equations and supported by numerous solved problems to help the student to understand the concepts clearly.Advances in Miniaturization of Electronic Systems by ever increasing packaging densities on Integrated Circuits has made it very essential for thorough Knowledge of the concepts, phenomenon, characteristics and behaviour of semiconductor Devices for students and professionals.

  20. Fluctuations in quantum devices

    Directory of Open Access Journals (Sweden)

    H.Haken

    2004-01-01

    Full Text Available Logical gates can be formalized by Boolean algebra whose elementary operations can be realized by devices that employ the interactions of macroscopic numbers of elementary excitations such as electrons, holes, photons etc. With increasing miniaturization to the nano scale and below, quantum fluctuations become important and can no longer be ignored. Based on Heisenberg equations of motion for the creation and annihilation operators of elementary excitations, I determine the noise sources of composite quantum systems.

  1. Fluctuations in quantum devices

    OpenAIRE

    Haken, H.

    2004-01-01

    Logical gates can be formalized by Boolean algebra whose elementary operations can be realized by devices that employ the interactions of macroscopic numbers of elementary excitations such as electrons, holes, photons etc. With increasing miniaturization to the nano scale and below, quantum fluctuations become important and can no longer be ignored. Based on Heisenberg equations of motion for the creation and annihilation operators of elementary excitations, I determine the noise sources of c...

  2. Memristor: the illusive device

    KAUST Repository

    Salama, Khaled N.

    2012-05-03

    The memristor (M) is considered to be the fourth two-terminal passive element in electronics, alongside the resistor (R), the capacitor (C), and the inductor (L). Its existence was postulated in 1971 but its first implementation was reported in 2008. Where was it hiding all that time and what can we do with it? Come and learn how the memristor completes the roster of electronic devices much like a missing particle that physicists seek to complete their tableaus.

  3. A power measuring device

    International Nuclear Information System (INIS)

    As a part of the klystron test facility of the Dutch NIKHEF-K accelerator, a sensitive power measuring device has been built. The high-frequency power of a klystron is stored in a water-cooled dummy load. Using a microcomputer, the increase of the water temperature and the water flow rate are transformed to a digital indication of the klystron power. (Auth.)

  4. Alignment reference device

    Science.gov (United States)

    Patton, Gail Y.; Torgerson, Darrel D.

    1987-01-01

    An alignment reference device provides a collimated laser beam that minimizes angular deviations therein. A laser beam source outputs the beam into a single mode optical fiber. The output end of the optical fiber acts as a source of radiant energy and is positioned at the focal point of a lens system where the focal point is positioned within the lens. The output beam reflects off a mirror back to the lens that produces a collimated beam.

  5. Spintronics in nanoscale devices

    CERN Document Server

    Hedin, Eric R

    2013-01-01

    By exploiting the novel properties of quantum dots and nanoscale Aharonov-Bohm rings together with the electronic and magnetic properties of various semiconductor materials and graphene, researchers have conducted numerous theoretical and computational modeling studies and experimental tests that show promising behavior for spintronics applications. Spin polarization and spin-filtering capabilities and the ability to manipulate the electron spin state through external magnetic or electric fields have demonstrated the promise of workable nanoscale devices for computing and memory applications.

  6. Hybrid electroluminescent devices

    Science.gov (United States)

    Shiang, Joseph John; Duggal, Anil Raj; Michael, Joseph Darryl

    2010-08-03

    A hybrid electroluminescent (EL) device comprises at least one inorganic diode element and at least one organic EL element that are electrically connected in series. The absolute value of the breakdown voltage of the inorganic diode element is greater than the absolute value of the maximum reverse bias voltage across the series. The inorganic diode element can be a power diode, a Schottky barrier diode, or a light-emitting diode.

  7. Incore inspection device

    International Nuclear Information System (INIS)

    The device of the present invention can inspect surfaces of equipments in reactor water in a nuclear reactor in a state of atmospheric air. Namely, an inspection device is movable forwardly and backwardly in a water-proof vessel. An annular sucker with pleats is disposed to the outer side of a lid of the water-proof vessel. A television camera for an under water monitoring is disposed to the inner side of the lid of the water-proof vessel by way of a partitioning wall with lid. Transferring screws are disposed at the back and on the side of the water-proof vessel. In the device having such a constitution, (1) the inside of the water-proof vessel is at first made water-tight by closing the partitioning wall with lid, (2) the back and the side screws are operated by the guide of the underwater monitoring television camera, to transfer the water-proof vessel to the surface of the reactor core to be inspected, (3) the annular sucker with pleats is urged on the surface to be inspected by the back screw, to fix the water-proof vessel, (4) reactor water in a space of the annular sucker with pleats is discharged and replaced with air, and (5) the lid of the partition wall with lid is opened and the inspection device is disposed at a position of the underwater monitoring television camera, to inspect the surface to be inspected in a state of atmospheric air. (I.S.)

  8. Incore instrument device

    International Nuclear Information System (INIS)

    An incore instrument device has an integrally disposed touch panel having a function of displaying an operation indication method such as for setting of conditions for incore measurement and information processing and results of the incore measurement and a function capable of conducting operation indication such as for setting conditions and information processing for incore measurement relative to a control section upon touching an information position on a displayed information. In addition, an information processing section comprising a man-machine function program formed so as to recognize the content of the operation indication for the incore measurement by touching and let the control section to conduct it is disposed to the outside by way of a communication interface. In addition, a programming device is disposed for forming and rewriting the program of the man-machine function relative to the information processing section. Then, when various indication operations are conducted upon performing incore measurement, a view point can be concentrated to one predetermined point thereby enabling to improve the operationability without danger. In addition, the programming of the man-machine function does not apply unnecessary load to the control section in the incore instrumentation device. (N.H.)

  9. DeviceNet-based device-level control in SSRF

    CERN Document Server

    Leng Yong Bin; Lu Cheng Meng; Miao Hai Feng; Liu Song Qiang; Shen Guo Bao

    2002-01-01

    The control system of Shanghai Synchrotron Radiation Facility is an EPICS-based distributed system. One of the key techniques to construct the system is the device-level control. The author describes the design and implementation of the DeviceNet-based device controller. A prototype of the device controller was tested in the experiments of magnet power supply and the result showed a precision of 3 x 10 sup - sup 5

  10. Advanced Semiconductor Devices

    Science.gov (United States)

    Shur, Michael S.; Maki, Paul A.; Kolodzey, James

    2007-06-01

    I. Wide band gap devices. Wide-Bandgap Semiconductor devices for automotive applications / M. Sugimoto ... [et al.]. A GaN on SiC HFET device technology for wireless infrastructure applications / B. Green ... [et al.]. Drift velocity limitation in GaN HEMT channels / A. Matulionis. Simulations of field-plated and recessed gate gallium nitride-based heterojunction field-effect transistors / V. O. Turin, M. S. Shur and D. B. Veksler. Low temperature electroluminescence of green and deep green GaInN/GaN light emitting diodes / Y. Li ... [et al.]. Spatial spectral analysis in high brightness GaInN/GaN light emitting diodes / T. Detchprohm ... [et al.]. Self-induced surface texturing of Al2O3 by means of inductively coupled plasma reactive ion etching in Cl2 chemistry / P. Batoni ... [et al.]. Field and termionic field transport in aluminium gallium arsenide heterojunction barriers / D. V. Morgan and A. Porch. Electrical characteristics and carrier lifetime measurements in high voltage 4H-SiC PiN diodes / P. A. Losee ... [et al.]. Geometry and short channel effects on enhancement-mode n-Channel GaN MOSFETs on p and n- GaN/sapphire substrates / W. Huang, T. Khan and T. P. Chow. 4H-SiC Vertical RESURF Schottky Rectifiers and MOSFETs / Y. Wang, P. A. Losee and T. P. Chow. Present status and future Directions of SiGe HBT technology / M. H. Khater ... [et al.]Optical properties of GaInN/GaN multi-quantum Wells structure and light emitting diode grown by metalorganic chemical vapor phase epitaxy / J. Senawiratne ... [et al.]. Electrical comparison of Ta/Ti/Al/Mo/Au and Ti/Al/Mo/Au Ohmic contacts on undoped GaN HEMTs structure with AlN interlayer / Y. Sun and L. F. Eastman. Above 2 A/mm drain current density of GaN HEMTs grown on sapphire / F. Medjdoub ... [et al.]. Focused thermal beam direct patterning on InGaN during molecular beam epitaxy / X. Chen, W. J. Schaff and L. F. Eastman -- II. Terahertz and millimeter wave devices. Temperature-dependent microwave performance of

  11. Novel Concepts for Device to Device Communication using Network Coding

    DEFF Research Database (Denmark)

    Pahlevani, Peyman; Hundebøll, Martin; Pedersen, Morten Videbæk;

    2014-01-01

    Device-to-device communication is currently a hot research topic within 3GPP. Even though D2D communication has been part of previous ad hoc, meshed and sensor networks proposals, the main contribution by 3GPP is that the direct communication among two devices is carried out over a dynamically as...

  12. An introduction to electrooptic devices

    CERN Document Server

    Kaminow, Ivan P

    1974-01-01

    An Introduction to Electrooptic Devices aims to present an introduction to the electrooptic effect and to summarize work on devices employing the electrooptic effect. The book provides the necessary background in classical crystal optics. The text then discusses topics including crystal symmetry, the tensor description of linear dielectric properties, propagation in anisotropic media, and passive crystal optic devices. The book also describes the phenomenological description of tensor nonlinear dielectric properties of crystals, with emphasis on the electrooptic effect; device design and appli

  13. Portable source identification device

    Science.gov (United States)

    Andersen, Eric S.; Samuel, Todd J.; Gervais, Kevin L.

    2005-05-01

    U.S. Customs and Border Protection (CBP) is the primary enforcement agency protecting the nation"s ports of entry. CBP is enhancing its capability to interdict the illicit import of nuclear and radiological materials and devices that may be used by terrorists. Pacific Northwest National Laboratory (PNNL) is providing scientific and technical support to CBP in their goal to enable rapid deployment of nuclear and radiation detection systems at U. S. ports of entry to monitor 100% of the incoming international traffic and cargo while not adversely impacting the operations or throughput of the ports. As the deployment of radiation detection systems proceeds, there is a need to adapt the baseline radiation portal monitor (RPM) system technology to operations at these diverse ports of entry. When screening produces an alarm in the primary inspection RPM, the alarming vehicle is removed from the flow of commerce and the alarm is typically confirmed in a secondary inspection RPM. The portable source identification device (PSID) is a radiation sensor panel (RSP), based on thallium-doped sodium iodide (NaI(Tl)) scintillation detector and gamma spectroscopic analysis hardware and software, mounted on a scissor lift on a small truck. The lift supports a box containing a commercial off-the-shelf (COTS) sodium iodide detector that provides real-time isotopic identification, including neutron detectors to interdict Weapons of Mass Destruction (WMD) and radiation dispersion devices (RDD). The scissor lift will lower the detectors to within a foot off the ground and raise them to approximately 24 feet (7.3 m) in the air, allowing a wide vertical scanning range.

  14. Modeling of graphene nanoribbon devices.

    Science.gov (United States)

    Guo, Jing

    2012-09-21

    Recent advances in graphene nanoribbon (GNR) electronic devices provide a concrete context for developing simulation methods, comparing theories to experiments, and using simulations to explore device physics. We present a review on modeling of graphene nanoribbon devices, with an emphasis on electronic and magnetoresistive devices. Device modeling is reviewed in a synergistic perspective with GNR material properties, device characteristics, and circuit requirements. Similarity with and difference to carbon nanotube devices are discussed. Device modeling and simulation results are compared to experimental data, which underlines the importance of theory-experiment collaborations in this field. Importance of the GNR edges, which have a negative impact on the carrier mobility due to edge roughness but offer new possibilities of spintronic devices and edge doping, is emphasized. Advanced device modeling of GNRs needs to have the capability to describe GNR device physics, including three-dimensional electrostatics, quantum and atomistic scale effects, elastic and inelastic scattering processes, electron-electron interaction, edge chemistry, magnetic field modulation, and spintronic and thermoelectric device phenomena. PMID:22875475

  15. Mechanical device for tissue regeneration

    NARCIS (Netherlands)

    Herder, J.L.; Maij, E.

    2010-01-01

    The invention relates to a mechanical device for tissue- regeneration inside a patient, comprising means (2, 3) to place a scaffold for the tissue under mechanical stress. Said means comprise a first device-part (2) and a second device-part (3) which parts are arranged to be movable with respect to

  16. Medical devices and patient safety.

    Science.gov (United States)

    Mattox, Elizabeth

    2012-08-01

    Errors related to health care devices are not well understood. Nurses in intensive care and progressive care environments can benefit from understanding manufacturer-related error and device-use error, the principles of human factors engineering, and the steps that can be taken to reduce risk of errors related to health care devices.

  17. A microfluidic device with pillars

    DEFF Research Database (Denmark)

    2014-01-01

    The invention provides a microfluidic device for mixing liquid reagents, the device comprises, a chip forming at least one reaction chamber between a bottom and a top and extending between an inlet and an outlet. To enable manufacturing from less rigid materials, the device comprises pillars...

  18. Fundamentals of power semiconductor devices

    CERN Document Server

    Baliga, BJayant

    2010-01-01

    Offers an in-depth treatment of the physics of operation of power semiconductor devices that are commonly used by the power electronics industry. This book shows analytical models for explaining the operation of various power semiconductor devices. It is suitable for practicing engineers in the power semiconductor device community.

  19. Electromechanical motion devices

    CERN Document Server

    Krause, Paul C; Pekarek, Steven D

    2012-01-01

    This text provides a basic treatment of modern electric machine analysis that gives readers the necessary background for comprehending the traditional applications and operating characteristics of electric machines-as well as their emerging applications in modern power systems and electric drives, such as those used in hybrid and electric vehicles. Through the appropriate use of reference frame theory, Electromagnetic Motion Devices, Second Edition introduces readers to field-oriented control of induction machines, constant-torque, and constant-power control of dc, permanent-magnet ac

  20. Nanoscale Electronic Devices

    Science.gov (United States)

    Jing, Xiaoye

    Continuous downscaling in microelectronics has pushed conventional CMOS technology to its physical limits, while Moore's Law has correctly predicted the trend for decades, each step forward is accompanied with unprecedented technological difficulties and near-exponential increase in cost. At the same time, however, demands for low-power, low-cost and high-speed devices have never diminished, instead, even more stringent requirements have been imposed on device performances. It is therefore crucial to explore alternative materials and device architectures in order to alleviate the pressure caused by downscaling. To this end, we investigated two different approaches: (1) InSb nanowire based field effect transistors (NWFETs) and (2) single walled carbon nanotube (SWCNT) -- peptide nucleic acid (PNA) --SWCNT conjugate. Two types of InSb nanowires were synthesized by template-assisted electrochemistry and chemical vapor deposition (CVD) respectively. In both cases, NWFETs were fabricated by electron beam lithography (EBL) and crystallinity was confirmed by transmission electron microscopy (TEM) and selected area diffraction (SAD) patterns. For electrochemistry nanowire, ambipolar conduction was observed with strong p-type conduction, the effect of thermal annealing on the conductivity was analyzed, a NWFET model that took into consideration the underlapped region in top-gated NWFET was proposed. Hole mobility in the channel was calculated to be 292.84 cm2V-1s -1 with a density of 1.5x1017/cm3. For CVD nanowire, the diameter was below 40nm with an average of 20nm. Vapor-liquid-solid (VLS) process was speculated to be the mechanism responsible for nanowire growth. The efficient gate control was manifested by high ION/I OFF ratio which was on the order of 106 and a small inverse subthreshold slope (chemically functionalized single walled carbon nanotubes to synthesize the conjugate and characterized its electrical properties. Negative differential resistance (NDR) was

  1. Data mining mobile devices

    CERN Document Server

    Mena, Jesus

    2013-01-01

    With today's consumers spending more time on their mobiles than on their PCs, new methods of empirical stochastic modeling have emerged that can provide marketers with detailed information about the products, content, and services their customers desire.Data Mining Mobile Devices defines the collection of machine-sensed environmental data pertaining to human social behavior. It explains how the integration of data mining and machine learning can enable the modeling of conversation context, proximity sensing, and geospatial location throughout large communities of mobile users

  2. Computed tomography device

    International Nuclear Information System (INIS)

    A computed tomography device comprising a subtraction unit which obtains differential data strings representing the difference between each time-serial projection data string of a group of projection data strings corresponding to a prospective reconstruction image generated by projection data strings acquired by a data acquisition system, a convolution unit which convolves each time-serial projection data string of the group of projection data strings corresponding to the prospective reconstruction image, and a back-projection unit which back-projects the convolved data strings

  3. Hybrid silicon evanescent devices

    Directory of Open Access Journals (Sweden)

    Alexander W. Fang

    2007-07-01

    Full Text Available Si photonics as an integration platform has recently been a focus of optoelectronics research because of the promise of low-cost manufacturing based on the ubiquitous electronics fabrication infrastructure. The key challenge for Si photonic systems is the realization of compact, electrically driven optical gain elements. We review our recent developments in hybrid Si evanescent devices. We have demonstrated electrically pumped lasers, amplifiers, and photodetectors that can provide a low-cost, scalable solution for hybrid integration on a Si platform by using a novel hybrid waveguide architecture, consisting of III-V quantum wells bonded to Si waveguides.

  4. Nanotube resonator devices

    Science.gov (United States)

    Jensen, Kenneth J; Zettl, Alexander K; Weldon, Jeffrey A

    2014-05-06

    A fully-functional radio receiver fabricated from a single nanotube is being disclosed. Simultaneously, a single nanotube can perform the functions of all major components of a radio: antenna, tunable band-pass filter, amplifier, and demodulator. A DC voltage source, as supplied by a battery, can power the radio. Using carrier waves in the commercially relevant 40-400 MHz range and both frequency and amplitude modulation techniques, successful music and voice reception has been demonstrated. Also disclosed are a radio transmitter and a mass sensor using a nanotube resonator device.

  5. Pneumatically actuated micropipetting device

    Science.gov (United States)

    Szita, Nicolas; Buser, Rudolf A.

    1998-03-01

    We have realized a valveless micropipetting device with an integrated sensor which can aspirate and dispense liquid volumes without any valves, hence without any reflow or dead volume. With an external pneumatic actuation, we have demonstrated aspirating and dispensing from 190nl of 6 (mu) l of water. Measurements showed a standard deviation of down to 1 percent. An integrated capacitive sensor will allow monitoring of the pressure throughout the pipetting process and detect malfunctions, e.g. clotting of the pipetting tip. It is our intention to use this demonstrated precise aspiration mechanism in combination with a micromachined reaction chamber and a miniaturized optical analysis system.

  6. Anisotropic metamaterial devices

    Directory of Open Access Journals (Sweden)

    Wei Xiang Jiang

    2009-12-01

    Full Text Available In the last few years, a rapid development has been achieved in a subject area, so called optical transformation, which is based on the property of metric invariance in Maxwell's equations. Optical transformation, also known as transformation optics, allows metamaterials to be tailor-made according to practical needs. In this paper, we have reviewed the recent progress on the parametric design of transformation devices, such as invisibility cloaks, electromagnetic (EM concentrator, EM-wave converter, etc. The technique of optical transformation can also be applied when the sources are included in the transformed space.

  7. COMMUNICATION - ORGANIZATIONS’ WORK DEVICE

    Directory of Open Access Journals (Sweden)

    LAVINIA HULEA

    2010-01-01

    Full Text Available Communication represents a complex process of transmitting messages, owing to which the emitter encodes the information transmitted through a specific channel towards a receiver that will decode it. Owing to communication, organizations transmit to their customers the fact that they are capable of meeting one of their needs, of settling a problem or of offering a profit. Non-verbal and para-verbal communications usually accompany verbal communication. The importance of assimilating the forms of communication is, at an organizational level, a complex device that determines the mastering of certain techniques, procedures, and algorithms of encoding and decoding intricate messages transmitted through various channels.

  8. Exploiting Windows Device Drivers

    Institute of Scientific and Technical Information of China (English)

    Piotr Bahia; ayarei(译)

    2008-01-01

    设备驱动漏洞现在正在增长成为Windows和其他操作系统安全的主要威胁。这是一个新领域,很少有公开的技术文档讲述这个方面。据我所知,第一个windows设备驱动攻击是由SEC-LABS小组在win32 Device Drivers Communication Vulnerabilities白皮书中提到的。

  9. Graphene device and method of using graphene device

    Science.gov (United States)

    Bouchiat, Vincent; Girit, Caglar; Kessler, Brian; Zettl, Alexander K.

    2015-08-11

    An embodiment of a graphene device includes a layered structure, first and second electrodes, and a dopant island. The layered structure includes a conductive layer, an insulating layer, and a graphene layer. The electrodes are coupled to the graphene layer. The dopant island is coupled to an exposed surface of the graphene layer between the electrodes. An embodiment of a method of using a graphene device includes providing the graphene device. A voltage is applied to the conductive layer of the graphene device. Another embodiment of a method of using a graphene device includes providing the graphene device without the dopant island. A dopant island is placed on an exposed surface of the graphene layer between the electrodes. A voltage is applied to the conductive layer of the graphene device. A response of the dopant island to the voltage is observed.

  10. Emissivity modulating electrochromic device

    Science.gov (United States)

    Demiryont, Hulya; Shannon, Kenneth C., III; Sheets, Judd

    2009-05-01

    The IR-ECDTM (Infra-Red ElectroChromic Device) variable emitance device (VED) is an all-solid-state monolithic vacuum deposited thin film system with a unique metamaterial IR transparent-electrode system which functions as an electrically controlled dimmable mirror in the IR region. The maximum reflectance corresponding to the bleached condition of the system is around 90% (low-e condition, e=0.1). The minimum reflectance reaches nearly zero in the colored condition of the system (high emittance, e=1). The average emissivity modulation of the IRECDTM is 0.7 in the 8-12 micron region, and at 9.7 micron (room temperature) it reaches a value of 0.9. Half and full emissivity modulations occur within 2 and10 minutes respectively. Because of its light weight (5g/m2), low voltage requirement (+/- 1 Volts), extremely good emissivity control properties (from 0 to 0.9 at 300K) and highly repeatable deposition process, the IR-ECDTM technology is very attractive for satellite thermal control applications. The IR-ECDTM has been under evaluation in a real space environment since March 8, 2007. This paper presents recent achievements of the IR-ECDTM including space test results.

  11. Carbon for sensing devices

    CERN Document Server

    Tagliaferro, Alberto

    2015-01-01

    This book reveals why carbon is playing such an increasingly prominent role as a sensing material. The various steps that transform a raw material in a sensing device are thoroughly presented and critically discussed.  The authors deal with all aspects of carbon-based sensors, starting from the various hybridization and allotropes of carbon, with specific focus on micro and nanosized carbons (e.g., carbon nanotubes, graphene) and their growth processes. The discussion then moves to the role of functionalization and the different routes to achieve it. Finally, a number of sensing applications in various fields are presented, highlighting the connection with the basic properties of the various carbon allotropes.  Readers will benefit from this book’s bottom-up approach, which starts from the local bonding in carbon solids and ends with sensing applications, linking the local hybridization of carbon atoms and its modification by functionalization to specific device performance. This book is a must-have in th...

  12. [Medical device use errors].

    Science.gov (United States)

    Friesdorf, Wolfgang; Marsolek, Ingo

    2008-01-01

    Medical devices define our everyday patient treatment processes. But despite the beneficial effect, every use can also lead to damages. Use errors are thus often explained by human failure. But human errors can never be completely extinct, especially in such complex work processes like those in medicine that often involve time pressure. Therefore we need error-tolerant work systems in which potential problems are identified and solved as early as possible. In this context human engineering uses the TOP principle: technological before organisational and then person-related solutions. But especially in everyday medical work we realise that error-prone usability concepts can often only be counterbalanced by organisational or person-related measures. Thus human failure is pre-programmed. In addition, many medical work places represent a somewhat chaotic accumulation of individual devices with totally different user interaction concepts. There is not only a lack of holistic work place concepts, but of holistic process and system concepts as well. However, this can only be achieved through the co-operation of producers, healthcare providers and clinical users, by systematically analyzing and iteratively optimizing the underlying treatment processes from both a technological and organizational perspective. What we need is a joint platform like medilab V of the TU Berlin, in which the entire medical treatment chain can be simulated in order to discuss, experiment and model--a key to a safe and efficient healthcare system of the future. PMID:19213452

  13. Thermoplastic tape compaction device

    Science.gov (United States)

    Campbell, V.W.

    1994-12-27

    A device is disclosed for bonding a thermoplastic tape to a substrate to form a fully consolidated composite. This device has an endless chain associated with a frame so as to rotate in a plane that is perpendicular to a long dimension of the tape, the chain having pivotally connected chain links with each of the links carrying a flexible foot member that extends outwardly from the chain. A selected number of the foot members contact the tape, after the heating thereof, to cause the heated tape to bond to the substrate. The foot members are each a thin band of metal oriented transversely to the chain, with a flexibility and width and length to contact the tape so as to cause the tape to conform to the substrate to achieve consolidation of the tape and the substrate. A biased leaf-type spring within the frame bears against an inner surface of the chain to provide the compliant pressure necessary to bond the tape to the substrate. The chain is supported by sprockets on shafts rotatably supported in the frame and, in one embodiment, one of the shafts has a drive unit to produce rotation such that the foot members in contact with the tape move at the same speed as the tape. Cooling jets are positioned along the frame to cool the resultant consolidated composite. 5 figures.

  14. Thermoplastic tape compaction device

    Science.gov (United States)

    Campbell, Vincent W.

    1994-01-01

    A device for bonding a thermoplastic tape to a substrate to form a fully consolidated composite. This device has an endless chain associated with a frame so as to rotate in a plane that is perpendicular to a long dimension of the tape, the chain having pivotally connected chain links with each of the links carrying a flexible foot member that extends outwardly from the chain. A selected number of the foot members contact the tape, after the heating thereof, to cause the heated tape to bond to the substrate. The foot members are each a thin band of metal oriented transversely to the chain, with a flexibility and width and length to contact the tape so as to cause the tape to conform to the substrate to achieve consolidation of the tape and the substrate. A biased leaf-type spring within the frame bears against an inner surface of the chain to provide the compliant pressure necessary to bond the tape to the substrate. The chain is supported by sprockets on shafts rotatably supported in the frame and, in one embodiment, one of the shafts has a drive unit to produce rotation such that the foot members in contact with the tape move at the same speed as the tape. Cooling jets are positioned along the frame to cool the resultant consolidated composite.

  15. Carbon based prosthetic devices

    Energy Technology Data Exchange (ETDEWEB)

    Devlin, D.J.; Carroll, D.W.; Barbero, R.S.; Archuleta, T. [Los Alamos National Lab., NM (US); Klawitter, J.J.; Ogilvie, W.; Strzepa, P. [Ascension Orthopedics (US); Cook, S.D. [Tulane Univ., New Orleans, LA (US). School of Medicine

    1998-12-31

    This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The project objective was to evaluate the use of carbon/carbon-fiber-reinforced composites for use in endoprosthetic devices. The application of these materials for the metacarpophalangeal (MP) joints of the hand was investigated. Issues concerning mechanical properties, bone fixation, biocompatibility, and wear are discussed. A system consisting of fiber reinforced materials with a pyrolytic carbon matrix and diamond-like, carbon-coated wear surfaces was developed. Processes were developed for the chemical vapor infiltration (CVI) of pyrolytic carbon into porous fiber preforms with the ability to tailor the outer porosity of the device to provide a surface for bone in-growth. A method for coating diamond-like carbon (DLC) on the articulating surface by plasma-assisted chemical vapor deposition (CVD) was developed. Preliminary results on mechanical properties of the composite system are discussed and initial biocompatibility studies were performed.

  16. Stretchable and foldable electronic devices

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, John A; Huang, Yonggang; Ko, Heung Cho; Stoykovich, Mark; Choi, Won Mook; Song, Jizhou; Ahn, Jong Hyun; Kim, Dae Hyeong

    2013-10-08

    Disclosed herein are stretchable, foldable and optionally printable, processes for making devices and devices such as semiconductors, electronic circuits and components thereof that are capable of providing good performance when stretched, compressed, flexed or otherwise deformed. Strain isolation layers provide good strain isolation to functional device layers. Multilayer devices are constructed to position a neutral mechanical surface coincident or proximate to a functional layer having a material that is susceptible to strain-induced failure. Neutral mechanical surfaces are positioned by one or more layers having a property that is spatially inhomogeneous, such as by patterning any of the layers of the multilayer device.

  17. Stretchable and foldable electronic devices

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, John A; Huang, Yonggang; Ko, Heung Cho; Stoykovich, Mark; Choi, Won Mook; Song, Jizhou; Ahn, Jong Hyun; Kim, Dae Hyeong

    2014-12-09

    Disclosed herein are stretchable, foldable and optionally printable, processes for making devices and devices such as semiconductors, electronic circuits and components thereof that are capable of providing good performance when stretched, compressed, flexed or otherwise deformed. Strain isolation layers provide good strain isolation to functional device layers. Multilayer devices are constructed to position a neutral mechanical surface coincident or proximate to a functional layer having a material that is susceptible to strain-induced failure. Neutral mechanical surfaces are positioned by one or more layers having a property that is spatially inhomogeneous, such as by patterning any of the layers of the multilayer device.

  18. Human Factors and Medical Devices

    International Nuclear Information System (INIS)

    Medical device hardware- and software-driven user interfaces should be designed to minimize the likelihood of use-related errors and their consequences. The role of design-induced errors in medical device incidents is attracting widespread attention. The U.S. Food and Drug Administration (FDA) is fully cognizant that human factors engineering is critical to the design of safe medical devices, and user interface design is receiving substantial attention by the agency. Companies are paying more attention to the impact of device design, including user instructions, upon the performance of those health professionals and lay users who operate medical devices. Concurrently, the FDA is monitoring human factors issues in its site inspections, premarket device approvals, and postmarket incident evaluations. Overall, the outlook for improved designs and safer device operation is bright

  19. Cybersecurity for Connected Diabetes Devices.

    Science.gov (United States)

    Klonoff, David C

    2015-09-01

    Diabetes devices are increasingly connected wirelessly to each other and to data-displaying reader devices. Threats to the accurate flow of information and commands may compromise the function of these devices and put their users at risk of health complications. Sound cybersecurity of connected diabetes devices is necessary to maintain confidentiality, integrity, and availability of the data and commands. Diabetes devices can be hacked by unauthorized agents and also by patients themselves to extract data that are not automatically provided by product software. Unauthorized access to connected diabetes devices has been simulated and could happen in reality. A cybersecurity standard designed specifically for connected diabetes devices will improve the safety of these products and increase confidence of users that the products will be secure. PMID:25883162

  20. Firewood preparation devices in 1994

    International Nuclear Information System (INIS)

    A review of the market situation regarding firewood preparation devices is presented. The information was collected from the answers to a mail questionnaire. The review is assumed to include all the leading manufacturers and importers. Firewood production devices were available from 26 manufacturers. The range of models amounted to over 70. These may be divided into three categories: 1. cutting devices: the most common solution being a cross-cutting circular saw. There were only a few of these on sale as it is quite easy to include a splitting device on the same frame. 2. Splitting devices: e.g. screw splitter and hydraulically powered splitter. About 20 models are available on the markets. Cross cutting and splitting devices: these are the most popular devices. A cross-cutting circular saw with screw or hydraulic splitter is the most common type. There are about 50 models available on the markets. Cross-cutting and splitting devices are often equipped with conveyor for transferring the split wood e.g. into a trailer. Chopping devices are delivered as tractor powered devices, as electric motor powered devices or as combustion engine powered devices. Some of them are equipped with a time saving feeding device enabling the next stem to be lifted into position while the previous one is being chopped. The Finnish Work Efficiency Institute's studies show that when cross-cutting and splitting of stems into pieces of 35-50 cm in length, productivity for one operator varies in between 0.8 - 3.2 m3/h, depending on the device and work method used. (6 refs., 1 fig., 2 tabs.)

  1. Laser beam steering device

    Science.gov (United States)

    Motamedi, M. E.; Andrews, A. P.; Gunning, W. J.

    1993-01-01

    Agile beam steering is a critical requirement for airborne and space based LIDAR and optical communication systems. Design and test results are presented for a compact beam steering device with low inertia which functions by dithering two complementary (positive and negative) binary optic microlens arrays relative to each other in directions orthogonal to the direction of light propagation. The miniaturized system has been demonstrated at scan frequencies as high as 300 Hz, generating a 13 x 13 spot array with a total field of view of 2.4 degrees. The design is readily extendable to a 9.5 degree field of view and a 52 x 52 scan pattern. The system is compact - less than 2 in. on a side. Further size reductions are anticipated.

  2. Electronic control devices

    International Nuclear Information System (INIS)

    The subject of these lectures is the translation of information from particle detectors to computers. Large solid angle general purpose detectors at the intersection regions of high energy e+e- storage rings and pp and pp storage rings are discussed. Three choices for data acquisition are reviewed: use CAMAC (Computer Aided Measurement and Control), start from scratch and design a system, or wait for the final version of the proposed FASTBUS to be developed. The do-it-yourself procedure includes designs of drift chamber discriminator, time to amplitude converter, and data card block diagram. Trigger systems, the fast decision making systems judging an event interesting enough for a read-out cycle to be initiated, are discussed. Finally, a FASTBUS system layout, with its goals of minimum bus speed, general system topologies, and support multiple smart devices is given

  3. Optically Reconfigurable Photonic Devices

    CERN Document Server

    Wang, Qian; Gholipour, Behrad; Wang, Chih-Ming; Yuan, Guanghui; Teng, Jinghua; Zheludev, Nikolay I

    2015-01-01

    Optoelectronic components with adjustable parameters, from variable-focal-length lenses to spectral filters that can change functionality upon stimulation, have enormous technological importance. Tuning of such components is conventionally achieved by either micro- or nano-mechanical actuation of their consitutive parts, stretching or application of thermal stimuli. Here we report a new dielectric metasurface platform for reconfigurable optical components that are created with light in a non-volatile and reversible fashion. Such components are written, erased and re-written as two-dimensional binary or grey-scale patterns into a nanoscale film of phase change material by inducing a refractive-index-changing phase-transition with tailored trains of femtosecond pulses. We combine germanium-antimony-tellurium-based films optimized for high-optical-contrast ovonic switching with a sub-wavelength-resolution optical writing process to demonstrate technologically relevant devices: visible-range reconfigurable bi-chr...

  4. Analytic device including nanostructures

    KAUST Repository

    Di, Fabrizio, E.

    2015-07-02

    A device for detecting an analyte in a sample comprising: an array including a plurality of pixels, each pixel including a nanochain comprising: a first nanostructure, a second nanostructure, and a third nanostructure, wherein size of the first nanostructure is larger than that of the second nanostructure, and size of the second nanostructure is larger than that of the third nanostructure, and wherein the first nanostructure, the second nanostructure, and the third nanostructure are positioned on a substrate such that when the nanochain is excited by an energy, an optical field between the second nanostructure and the third nanostructure is stronger than an optical field between the first nanostructure and the second nanostructure, wherein the array is configured to receive a sample; and a detector arranged to collect spectral data from a plurality of pixels of the array.

  5. Efficient thermoelectric device

    Science.gov (United States)

    Ila, Daryush (Inventor)

    2010-01-01

    A high efficiency thermo electric device comprising a multi nanolayer structure of alternating insulator and insulator/metal material that is irradiated across the plane of the layer structure with ionizing radiation. The ionizing radiation produces nanocrystals in the layered structure that increase the electrical conductivity and decrease the thermal conductivity thereby increasing the thermoelectric figure of merit. Figures of merit as high as 2.5 have been achieved using layers of co-deposited gold and silicon dioxide interspersed with layers of silicon dioxide. The gold to silicon dioxide ratio was 0.04. 5 MeV silicon ions were used to irradiate the structure. Other metals and insulators may be substituted. Other ionizing radiation sources may be used. The structure tolerates a wide range of metal to insulator ratio.

  6. Elongated toroid fusion device

    International Nuclear Information System (INIS)

    A device for achieving ignition of a plasma with ohmic heating is described comprising: means for defining a toroidal plasma chamber,a and confining gas therein, and means including electrically conductive coils for generating plasma within the chamber and for confining and shaping such plasma substantially into and filling a predetermined single region of the chamber without an axisymmetric internal separatix and ohmically heating the confined plasma to ignition. The predetermined region is toroidal with a major axis defining an axial direction parallel thereto and a transaxial direction perpendicular to the axis and having an axial cross section with an elongation, k, greater than 4, where k is the ratio of the maximum axial dimension of the cross section to the maximum transaxial dimension of the cross section

  7. Ceramics for fusion devices

    International Nuclear Information System (INIS)

    Ceramics are required for a number of applications in fusion devices, among the most critical of which are magnetic coil insulators, windows for RF heating systems, and structural uses. Radiation effects dominate consideration of candidate materials, although good pre-irradiation properties are a requisite. Materials and components can be optimized by careful control of chemical and microstructural content, and application of brittle material design and testing techniques. Future directions for research and development should include further extension of the data base in the areas of electrical, structural, and thermal properties; establishment of a fission neutron/fusion neutron correlation including transmutation gas effects; and development of new materials tailored to meet the specific needs of fusion reactors

  8. False color viewing device

    International Nuclear Information System (INIS)

    A viewing device for observing objects in near-infrared false-color comprising a pair of goggles with one or more filters in the apertures, and pads that engage the face for blocking stray light from the sides so that all light reaching the user's eyes come through the filters. The filters attenuate most visible light and pass near-infrared (having wavelengths longer than approximately 700 nm) and a small amount of blue-green and blue-violet (having wavelengths in the 500 to 520 nm and shorter than 435 nm, respectively). The goggles are useful for looking at vegetation to identify different species and for determining the health of the vegetation, and to detect some forms of camouflage. 7 figs

  9. Driver's condition control devices.

    Directory of Open Access Journals (Sweden)

    V. B. Yashan

    2011-06-01

    Full Text Available The article describes the various types of biotechnical systems of transport security, that often called by general title "Antison. Their main disadvantage is the uncertainty of detecting drowsiness phase of driver’s state and the absence of biological feedbacks, that providing control of functional parameters of a human-driver in a mode of adaptation. Structurally, these systems are complicated by the presence of contact with the driver of sensors that restrict the freedom of his movements. There is described experiment, which was carried out in Greece in 2008, and where tested different types of systems which include motion sensors, EEG monitoring for the eyes, the recognition of road markings, control automotive electrical system. The results showed the feasibility of using sleep prevent devices.

  10. Millimeter wave nonreciprocal devices

    Science.gov (United States)

    Morgenthaler, F. R.

    1983-01-01

    The Microwave and Quantum Magnetics Group within the MIT Department of Electrical Engineering and Computer Science and the Research Laboratory of Electronics proposed a three year research program aimed at developing coherent magnetic wave signal-processing techniques for microwave energy which may form either the primary signal or else the intermediate frequency (IF) modulation of millimeter wavelength signals-especially at frequencies in the 50-94 GHz. range. Emphasis has been placed upon developing advanced types of signal processors that make use of quasi-optical propagation of electromagnetic and magnetostatic waves propagating in high quality single crystal ferrite thin films. A strong theoretical effort is required in order to establish valid models useful for predicting device performance. We emphasized new filter and circulator designs that employ combinations of the Faraday effect, field displacement nonreciprocity and magnetostatic resonance and periodic structures.

  11. False color viewing device

    Science.gov (United States)

    Kronberg, J.W.

    1992-10-20

    A viewing device for observing objects in near-infrared false-color comprising a pair of goggles with one or more filters in the apertures, and pads that engage the face for blocking stray light from the sides so that all light reaching the user's eyes come through the filters. The filters attenuate most visible light and pass near-infrared (having wavelengths longer than approximately 700 nm) and a small amount of blue-green and blue-violet (having wavelengths in the 500 to 520 nm and shorter than 435 nm, respectively). The goggles are useful for looking at vegetation to identify different species and for determining the health of the vegetation, and to detect some forms of camouflage. 7 figs.

  12. QoE-Aware Device-to-Device Multimedia Communications

    Directory of Open Access Journals (Sweden)

    Liang ZHOU

    2015-08-01

    Full Text Available Multimedia services over mobile device-to-device (D2D networks has recently received considerable attention. In this scenario, each device is equipped with a cellular communication interface, as well as a D2D interface over a shared medium. In this work, we study the performance properties of the mobile D2D communications in the framework of user satisfaction, and develop a fully distributed QoE-aware multimedia communication scheme (QAMCS. Specifically, we translate the opportunistic multimedia communications issue into a stochastic optimization problem, which opens up a new degree of performance to exploit. Moreover, QAMCS is designed for a heterogeneous and dynamic environment, in which user demand, device mobility, and transmission fashion may vary across different devices and applications. Importantly, QAMCS is able to maximize the user satisfaction and only needs each device to implement its own scheme individually in the absence of a central controller.

  13. Current devices of respiratory physiotherapy

    OpenAIRE

    Hristara-Papadopoulou, A; Tsanakas, J; Diomou, G; Papadopoulou, O.

    2008-01-01

    In recent years patients with respiratory diseases use various devices, which help the removal of mucus from the airways and the improvement of pulmonary function. The aim of the present study is to determine the effectiveness of the current devices of respiratory physiotherapy, as it comes from the review of literature. The current devices of physiotherapy for patients with respiratory diseases, are presented as an alternative therapy method or a supplemental therapy and they can motivate pa...

  14. Optoelectronic devices toward monolithic integration

    Science.gov (United States)

    Ghergia, V.

    1992-12-01

    Starting from the present state of tl art of discrete devices up to the on going realization of monolithic semicorxtuctor integrated prototypes an overview ofoptoelectronic devices for telecom applications is given inchiding a short classification of the different kind of integrated devices. On the future perspective of IBCN distribution network some economica of hybrid and monolithic forms of integration are attempted. lnaflyashoitpresentationoftheactivitiesperformedintbefieldofmonolithic integration by EEC ESPR1T and RACE projects is reported. 1.

  15. Barriers to medical device innovation

    Directory of Open Access Journals (Sweden)

    Bergsl

    2014-06-01

    Full Text Available Jacob Bergsland, Ole Jakob Elle, Erik Fosse The Intervention Centre, Oslo University Hospital, Institute of Clinical Medicine, University of Oslo, Oslo, Norway Abstract: The US Food and Drug Administration (FDA has defined a medical device as a health care product that does not achieve it's purpose by chemical action or by being metabolized. This means that a vast number of products are considered medical devices. Such devices play an essential role in the practice of medicine. The FDA classifies medical devices in three classes, depending on the risk of the device. Since Class I and II devices have relatively simple requirements for getting to the market, this review will focus on “implantable devices”, which, in general, belong to Class III. The European Union and Canada use a slightly different classification system. While early generations of medical devices were introduced without much testing, either technical or clinical, the process of introducing a Class III medical device from concept to clinical practice has become strongly regulated and requires extensive technological and clinical testing. The modern era of implantable medical devices may be considered to have started in the 1920s with development of artificial hips. The implantable pacemaker was another milestone and pacemakers and cardioverters/defibrillators have since saved millions of lives and created commercial giants in the medical device industry. This review will include some examples of cardiovascular devices. Similar considerations apply to the total implantable device market, although clinical and technological applications obviously vary considerably. Keyword: implantable, FDA, regulation, CE-mark, innovation

  16. Mobile device security for dummies

    CERN Document Server

    Campagna, Rich; Krishnan, Ashwin

    2011-01-01

    The information you need to avoid security threats on corporate mobile devices Mobile devices have essentially replaced computers for corporate users who are on the go and there are millions of networks that have little to no security. This essential guide walks you through the steps for securing a network and building a bulletproof framework that will protect and support mobile devices in the enterprise. Featuring real-world case scenarios, this straightforward guide shares invaluable advice for protecting mobile devices from the loss of sensitive and confidential corporate informati

  17. Digital forensics for handheld devices

    CERN Document Server

    Doherty, Eamon P

    2012-01-01

    Approximately 80 percent of the world's population now owns a cell phone, which can hold evidence or contain logs about communications concerning a crime. Cameras, PDAs, and GPS devices can also contain information related to corporate policy infractions and crimes. Aimed to prepare investigators in the public and private sectors, Digital Forensics for Handheld Devices examines both the theoretical and practical aspects of investigating handheld digital devices. This book touches on all areas of mobile device forensics, including topics from the legal, technical, academic, and social aspects o

  18. Fibre Optic Communication Key Devices

    CERN Document Server

    Grote, Norbert

    2012-01-01

    The book gives an in-depth description of the key devices of current and next generation fibre optic communication networks. In particular, the book covers devices such as semiconductor lasers, optical amplifiers, modulators, wavelength filters, and detectors but the relevant properties of optical fibres as well. The presentations include the physical principles underlying the various devices, the technologies used for the realization of the different devices, typical performance characteristics and limitations, and development trends towards more advanced components are also illustrated. Thus the scope of the book spans relevant principles, state-of-the-art implementations, the status of current research and expected future components.

  19. Hot gas handling device and motorized vehicle comprising the device

    NARCIS (Netherlands)

    Klein Geltink, J.; Beukers, A.; Van Tooren, M.J.L.; Koussios, S.

    2012-01-01

    The invention relates to a device for handling hot exhaust gasses discharged from an internal combustion engine. The device comprises a housing (2), enclosing a space (3) for transporting the exhaust gasses. The housing (2) is provided with an entrance - opening (4) for the exhaust gasses discharged

  20. 77 FR 69488 - Medical Devices; Custom Devices; Request for Comments

    Science.gov (United States)

    2012-11-19

    ... Food, Drug, and Cosmetic Act (the FD&C Act). The Food and Drug Administration (FDA) is in the process... HUMAN SERVICES Food and Drug Administration Medical Devices; Custom Devices; Request for Comments AGENCY: Food and Drug Administration, HHS. ACTION: Notice; request for comments. SUMMARY: The Food and...

  1. 76 FR 8637 - Medical Devices; Medical Device Data Systems

    Science.gov (United States)

    2011-02-15

    ... this organizational change to provide clarification of MDDS functionality and because this ordering is... of an order classifying the device in class I or class II. To change the classification of the device... which is of substantial importance in preventing impairment of human health or it presents a...

  2. ITER tokamak device

    Science.gov (United States)

    Doggett, J.; Salpietro, E.; Shatalov, G.

    1991-07-01

    The results of the Conceptual Design Activities for the International Thermonuclear Experimental Reactor (ITER) are summarized. These activities, carried out between April 1988 and December 1990, produced a consistent set of technical characteristics and preliminary plans for co-ordinated research and development support of ITER, a conceptual design, a description of design requirements and a preliminary construction schedule and cost estimate. After a description of the design basis, an overview is given of the tokamak device, its auxiliary systems, facility and maintenance. The interrelation and integration of the various subsystems that form the ITER tokamak concept are discussed. The 16 ITER equatorial port allocations, used for nuclear testing, diagnostics, fueling, maintenance, and heating and current drive, are given, as well as a layout of the reactor building. Finally, brief descriptions are given of the major ITER sub-systems, i.e., (1) magnet systems (toroidal and poloidal field coils and cryogenic systems), (2) containment structures (vacuum and cryostat vessels, machine gravity supports, attaching locks, passive loops and active coils), (3) first wall, (4) divertor plate (design and materials, performance and lifetime, a.o.), (5) blanket/shield system, (6) maintenance equipment, (7) current drive and heating, (8) fuel cycle system, and (9) diagnostics.

  3. Simulation of semiconductor devices

    CERN Document Server

    Oriato, D

    2001-01-01

    cathode, made using an AIGaAs heterostructure step. Simulations show the importance of the insertion of a thin highly-doped layer between the transit region and the electron launcher in order to improve device operation. Chapter 5 is an introduction to Ill-nitrides, in particular GaN and its alloy ln-GaN. We outline the discrepancy in the elastic and piezoelectric parameters found in the literature. Strain, dislocations and piezoelectricity are presented as the main features of a InGaN/GaN system. In chapter 6 an extensive simulation of the dependence of the optical band gap of a single InGaN quantum well on the piezoelectric and spontaneous polarization is reported. Quantum Confined Stark Effect and screening mechanisms are found to play a major role. The simulation of a novel InGaN/GaN double quantum well LED is presented. A wide well is used to capture electrons that tunnels in a narrow well where they recombine with holes. Resonant asymmetric tunneling of electron and holes is used to increase the efficie...

  4. Radioactive iodine removing device

    International Nuclear Information System (INIS)

    In a radioactive iodine removing device of an off-gas processing step in a spent fuel reprocessing facility, spiral structures having an inclination of more than about 20deg is disposed at the inside of an iodine adsorbent packing portion, and dampers are disposed at a packing inlet and a discharging exit for iodine adsorbents respectively. After completion of discharge of the iodine adsorbents, a damper disposed in the midway of a adsorbent packing pipeline is opened for packing the iodine absorbents. The iodine adsorbents used have a spherical shape of 10 to 20 mesh (1 to 2mm), and the adsorbents are packed uniformly both radially and vertically to the packing portion upon injection of the adsorbents and, as a result, the packing portion can be made compact. Further, since the discharged iodine adsorbents can be contained in a vessel directly or in a different vessel having an excellent containing performance by taking the dimension of the vessel into consideration, it is possible to reduce the generation amount of wastes than that in a conventional case. (N.H.)

  5. 77 FR 51571 - Certain Wireless Communication Devices, Portable Music and Data Processing Devices, Computers...

    Science.gov (United States)

    2012-08-24

    ... COMMISSION Certain Wireless Communication Devices, Portable Music and Data Processing Devices, Computers, and.... International Trade Commission has received a complaint entitled Wireless Communication Devices, Portable Music... communication devices, portable music and data processing devices, computers, and components thereof....

  6. 77 FR 58576 - Certain Wireless Communication Devices, Portable Music and Data Processing Devices, Computers...

    Science.gov (United States)

    2012-09-21

    ... COMMISSION Certain Wireless Communication Devices, Portable Music and Data Processing Devices, Computers, and... importation of certain wireless communication devices, portable music and data processing devices, computers... after importation of certain wireless communication devices, portable music and data processing...

  7. Polymer Thermoelectric Generators: Device Considerations

    Science.gov (United States)

    Yee, Shannon

    2014-03-01

    Recent control of the transport properties in polymers has encouraged the development of polymer thermoelectric (TE) devices. Polymer TEs are thought to be less expensive and more scalable than their inorganic counterparts. The cost of the raw material is less and polymer TEs can leverage the large areal manufacturing technique established by the plastics industry. Additionally, while the overall ZT of polymer TEs appears attractive, individual polymer properties have a very different scale than their inorganic counterparts (i.e., the thermal conductivity and electrical conductivity are approximately one and two orders of magnitude smaller, respectively). Furthermore, the majority of TE measurements on polymers have been limited to thin-films where traditional TE materials are measured in bulk. So why should it be expected that polymer TE devices resemble traditional TE devices? Given the uniqueness of polymers, different device architectures are proposed that can leverage the unique strengths of polymer films. It will be shown that by logically considering device requirements, new polymer TE devices have non-linear features that are more attractive than linear inorganic TE devices. This leads to very different device optimizations that favor polymer TEs.

  8. Plugging device for nuclear pipes

    International Nuclear Information System (INIS)

    The plugging device assembled near an access opening is used for plugging the primary pipes. This plugging device comprises a rim flexible joint put in mechanical pressure by the displacement of mechanical pieces. This joint has a central compartment pressurizable. This joint is fixed by a stirrup-piece and a shaft in support on the tube plate

  9. Insertion device vacuum system designs

    International Nuclear Information System (INIS)

    Synchrotron light source insertion device vacuum systems now in operation and systems proposed for the future are reviewed. An overview of insertion devices is given and four generic vacuum chamber designs, transition section design and pumping considerations are discussed. Examples of vacuum chamber systems are presented

  10. Documentation of Appliances & Interaction Devices

    DEFF Research Database (Denmark)

    2004-01-01

    The interaction devices and appliances explored in the WorkSPACE project, address spatial computing in the context of work. We have developed and explored a range of appliances and interaction devices. The scope has been to develop tools for support of collaboration by mixing digital and physical...

  11. Personalized Adaptation to Device Characteristics

    NARCIS (Netherlands)

    Herder, E.; Dijk, van E.M.A.G.; de Bra, P.; Brusilovsky, P.; Conejo, R.

    2002-01-01

    Device characteristics, such as screen size and means of interaction, and the context in which a device is used, seriously affect the user’s mental representation of an information environment and its intended use. We hypothesize that user characteristics are valuable resources for determining which

  12. Electrical nanogap devices for biosensing

    Directory of Open Access Journals (Sweden)

    Xing Chen

    2010-11-01

    Full Text Available For detecting substances that are invisible to the human eye or nose, and particularly those biomolecules, the devices must have very small feature sizes, be compact and provide a sufficient level of sensitivity, often to a small number of biomolecules that are just a few nanometres in size. Electrical nanogap devices for biosensing have emerged as a powerful technique for detecting very small quantities of biomolecules. The most charming feature of the devices is to directly transduce events of biomolecules specific binding into useful electrical signals such as resistance/impedance, capacitance/dielectric, or field-effect. Nanogap devices in electrical biosensing have become a busy area of research which is continually expanding. A wealth of research is available discussing planar and vertical nanogap devices for biosensing. Planar nanogap devices including label-free, gold nanoparticle-labeled, nanoparticles-enhanced, nanogapped gold particle film, and carbon nanotube nanogap devices as well as vertical nanogap devices with two and three terminals for biosensing are carefully reviewed. The aim of this paper is to provide an updated overview of the work in this field. In each part, we discuss the principles of operation of electrical biosensing and consider major strategies for enhancing their performance and/or key challenges and opportunities in current stages, and in their further development.

  13. Mixing in a Microfluid Device

    DEFF Research Database (Denmark)

    Hjorth, Poul G.; Deryabin, Mikhail

    Mixing of fluids in microchannels cannot rely on turbulence since the flow takes place at extremly low Reynolds numbers. Various active and passive devices have been developed to induce mixing in microfluid flow devices. We describe here a model of an active mixer where a transverse periodic flow...

  14. Wound Healing Devices Brief Vignettes

    OpenAIRE

    Anderson, Caesar A.; Hare, Marc A.; Perdrizet, George A.

    2016-01-01

    Significance: The demand for wound care therapies is increasing. New wound care products and devices are marketed at a dizzying rate. Practitioners must make informed decisions about the use of medical devices for wound healing therapy. This paper provides updated evidence and recommendations based on a review of recent publications.

  15. Selection of Air Terminal Device

    DEFF Research Database (Denmark)

    Nielsen, Peter V.

    This paper discusses the selection of the air terminal device for the experiments and numerical prediction in the International Energy Agency Annex 20 work: Air Flow Pattern within Buildings,......This paper discusses the selection of the air terminal device for the experiments and numerical prediction in the International Energy Agency Annex 20 work: Air Flow Pattern within Buildings,...

  16. Sample processing device and method

    DEFF Research Database (Denmark)

    2011-01-01

    A sample processing device is disclosed, which sample processing device comprises a first substrate and a second substrate, where the first substrate has a first surface comprising two area types, a first area type with a first contact angle with water and a second area type with a second contact...

  17. Satellite and acoustic tracking device

    KAUST Repository

    Berumen, Michael L.

    2014-02-20

    The present invention relates a method and device for tracking movements of marine animals or objects in large bodies of water and across significant distances. The method and device can track an acoustic transmitter attached to an animal or object beneath the ocean surface by employing an unmanned surface vessel equipped with a hydrophone array and GPS receiver.

  18. Speech Recognition on Mobile Devices

    DEFF Research Database (Denmark)

    Tan, Zheng-Hua; Lindberg, Børge

    2010-01-01

    The enthusiasm of deploying automatic speech recognition (ASR) on mobile devices is driven both by remarkable advances in ASR technology and by the demand for efficient user interfaces on such devices as mobile phones and personal digital assistants (PDAs). This chapter presents an overview of ASR...

  19. Nanoscale wicking methods and devices

    Science.gov (United States)

    Zhou, Jijie (Inventor); Bronikowski, Michael (Inventor); Noca, Flavio (Inventor); Sansom, Elijah B. (Inventor)

    2011-01-01

    A fluid transport method and fluid transport device are disclosed. Nanoscale fibers disposed in a patterned configuration allow transport of a fluid in absence of an external power source. The device may include two or more fluid transport components having different fluid transport efficiencies. The components may be separated by additional fluid transport components, to control fluid flow.

  20. Optical device for straightness measurement

    Science.gov (United States)

    Vekteris, Vladas; Jurevicius, Mindaugas; Turla, Vytautas

    2015-11-01

    The present paper describes the research of the optical device for two-dimensional straightness measurement of technological machines. Mathematical study of an optical device, operating on the phase principle and measuring transversal displacements of machine parts in two directions ( X and Y) during their linear longitudinal motion in a machine (alongside the Z axis), is presented. How to estimate the range of travel along the Z axis is analytically shown. At this range, the measurer gives correct measurements of transverse displacement. The necessary distance from the objective focus to the image plane was defined mathematically. The sample results of measuring the displacement of the table of a technological machine by using the optical device are presented in the paper. This optical device for non-contact straightness measurement can be used for measurement straightness in turning, milling, drilling, grinding machines and other technological machines, also in geodesy and cartography, and for moving accuracy testing of mechatronic devices, robotics and others.

  1. Content Sharing for Mobile Devices

    CERN Document Server

    Ball, Rudi

    2008-01-01

    The miniaturisation of computing devices has seen computing devices become increasingly pervasive in society. With this increased pervasiveness, the technologies of small computing devices have also improved. Mobile devices are now capable of capturing various forms of multimedia and able to communicate wirelessly using increasing numbers of communication techniques. The owners and creators of local content are motivated to share this content in ever increasing volume; the conclusion has been that social networks sites are seeing a revolution in the sharing of information between communities of people. As load on centralised systems increases, we present a novel decentralised peer-to-peer approach dubbed the Market Contact Protocol (MCP) to achieve cost effective, scalable and efficient content sharing using opportunistic networking (pocket switched networking), incentive, context-awareness, social contact and mobile devices. Within the report we describe how the MCP is simulated with a superimposed geographi...

  2. Pressurized waterproof case electronic device

    KAUST Repository

    Berumen, Michael L.

    2013-01-31

    A pressurized waterproof case for an electronic device is particularly adapted for fluid-tight containment and operation of a touch-screen electronic device or the like therein at some appreciable water depth. In one example, the case may be formed as an enclosure having an open top panel or face covered by a flexible, transparent membrane or the like for the operation of the touchscreen device within the case. A pressurizing system is provided for the case to pressurize the case and the electronic device therein to slightly greater than ambient in order to prevent the external water pressure from bearing against the transparent membrane and pressing it against the touch screen, thereby precluding operation of the touch screen device within the case. The pressurizing system may include a small gas cartridge or may be provided from an external source.

  3. Device Applications of Nonlinear Dynamics

    CERN Document Server

    Baglio, Salvatore

    2006-01-01

    This edited book is devoted specifically to the applications of complex nonlinear dynamic phenomena to real systems and device applications. While in the past decades there has been significant progress in the theory of nonlinear phenomena under an assortment of system boundary conditions and preparations, there exist comparatively few devices that actually take this rich behavior into account. "Device Applications of Nonlinear Dynamics" applies and exploits this knowledge to make devices which operate more efficiently and cheaply, while affording the promise of much better performance. Given the current explosion of ideas in areas as diverse as molecular motors, nonlinear filtering theory, noise-enhanced propagation, stochastic resonance and networked systems, the time is right to integrate the progress of complex systems research into real devices.

  4. Pyrotechnic devices and their applications

    Science.gov (United States)

    Himelblau, Harry

    2002-05-01

    Pyroshock is mechanical shock transmitted through structures from explosive devices, sometimes accompanied by structural impact. These devices are designed to cause the intentional separation of structures, or to cause the deployment of various mechanisms or subsystems required for mission operation. Separation devices usually fall into two categories: (a) line sources, such as linear shaped charges, and (b) point sources, such as explosive bolts, pin puller and pushers, and gas generators. The advantages of these devices are high reliability (especially when redundantly activated), low cost and weight, high activation speed, and low structural deformation a short distance from the source. The major limitation is pyroshock, a severe high-frequency transient capable of causing failure or malfunction to small nearby elements, especially electronic and optical components located close to the source. This pyroshock tutorial, which is intended to summarize recent improvements to the technology, is initiated with a review of explosive and companion devices.

  5. Surgical tools and medical devices

    CERN Document Server

    Jackson, Mark

    2016-01-01

    This new edition presents information and knowledge on the field of biomedical devices and surgical tools. The authors look at the interactions between nanotechnology, nanomaterials, design, modeling, and tools for surgical and dental applications, as well as how nanostructured surfaces can be created for the purposes of improving cell adhesion between medical devices and the human body. Each original chapter is revised in this second edition and describes developments in coatings for heart valves, stents, hip and knee joints, cardiovascular devices, orthodontic applications, and regenerative materials such as bone substitutes. There are also 8 new chapters that address: Microvascular anastomoses Inhaler devices used for pulmonary delivery of medical aerosols Surface modification of interference screws Biomechanics of the mandible (a detailed case study) Safety and medical devices The synthesis of nanostructured material Delivery of anticancer molecules using carbon nanotubes Nano and micro coatings for medic...

  6. Turi device for radioactive source transport in the MUK device

    International Nuclear Information System (INIS)

    The TURI radioactive source transport device for on-line studies with a mass spectrometer in a proton beam is described. This device is a part of the multidetector MUK-device the aim of which is the measurement of the angular correlations and lifetimes observed in radioactive decay of short-lived nuclei (T1/2>0.1 s). The TURY system ensures the velocity of the radioactive target movement 1 cm per 0.25 s, and microcomputer control of experiment the accuracy of the tape stop is 0.15 mm

  7. Ontology-Based Device Descriptions and Device Repository for Building Automation Devices

    Directory of Open Access Journals (Sweden)

    Dibowski Henrik

    2011-01-01

    Full Text Available Device descriptions play an important role in the design and commissioning of modern building automation systems and help reducing the design time and costs. However, all established device descriptions are specialized for certain purposes and suffer from several weaknesses. This hinders a further design automation, which is strongly needed for the more and more complex building automation systems. To overcome these problems, this paper presents novel Ontology-based Device Descriptions (ODDs along with a layered ontology architecture, a specific ontology view approach with virtual properties, a generic access interface, a triple store-based database backend, and a generic search mask GUI with underlying query generation algorithm. It enables a formal, unified, and extensible specification of building automation devices, ensures their comparability, and facilitates a computer-enabled retrieval, selection, and interoperability evaluation, which is essential for an automated design. The scalability of the approach to several ten thousand devices is demonstrated.

  8. Multilayer polymer light emitting devices

    Science.gov (United States)

    Barcikowski, Zachary; Thomas, Adam; Tzolov, Marian

    2013-03-01

    The interplay of device layers and their interfaces is a major area of study in Polymer Light Emitting Devices (PLEDs). Many factors such as the degradation, efficiency, and overall performance depend on how these layers interact with each other. A fundamental understanding of the interfaces of these layers can lend to better performing devices using a multitude of organic polymers deposited in conjunction with each other in several ways. We have studied basic PLED devices in which we vary the emissive layer used, along with final bake temperatures. Devices include a glass substrate with Indium Tin Oxide anode, Aluminum cathode, and Plexcore Hole Injection layer. The active polymer films were spin casted from solution of MEH-PPV and PFO. Single layer and dual layers of several polymers are studied by examining current-voltage characteristics, film densities, impedance measurements, light emission, and efficiency calculations. We have found that not only do dual layers positively alter the performance of the device in the majority of cases, but the solvents in which each layer is originally in when deposited affects the formation of the interface, thereby altering the device mechanisms.

  9. High voltage MOSFET devices and methods of making the devices

    Energy Technology Data Exchange (ETDEWEB)

    Banerjee, Sujit; Matocha, Kevin; Chatty, Kiran

    2015-12-15

    A SiC MOSFET device having low specific on resistance is described. The device has N+, P-well and JFET regions extended in one direction (Y-direction) and P+ and source contacts extended in an orthogonal direction (X-direction). The polysilicon gate of the device covers the JFET region and is terminated over the P-well region to minimize electric field at the polysilicon gate edge. In use, current flows vertically from the drain contact at the bottom of the structure into the JFET region and then laterally in the X direction through the accumulation region and through the MOSFET channels into the adjacent N+ region. The current flowing out of the channel then flows along the N+ region in the Y-direction and is collected by the source contacts and the final metal. Methods of making the device are also described.

  10. Hot gas handling device and motorized vehicle comprising the device

    OpenAIRE

    Klein Geltink, J.; Beukers, A.; Van Tooren, M.J.L.; Koussios, S.

    2012-01-01

    The invention relates to a device for handling hot exhaust gasses discharged from an internal combustion engine. The device comprises a housing (2), enclosing a space (3) for transporting the exhaust gasses. The housing (2) is provided with an entrance - opening (4) for the exhaust gasses discharged from the engine and an exit-opening (5) for transporting the exhaust gasses away from the engine, and comprises a flexible thermal insulating layer, arranged for resisting the temperature of the e...

  11. Mobile device-to-device distributed computing using data sets

    OpenAIRE

    Remédios, Diogo; Teófilo, António; Paulino, Hervé; Lourenço, João

    2015-01-01

    The rapidly increasing computing power, available storage and communication capabilities of mobile devices makes it possible to start processing and storing data locally, rather than offloading it to remote servers; allowing scenarios of mobile clouds without infrastructure dependency. We can now aim at connecting neighboring mobile devices, creating a local mobile cloud that provides storage and computing services on local generated data. In this paper, we describe an early overview of a dis...

  12. Life cycle of mobile devices

    Directory of Open Access Journals (Sweden)

    T.V. Rohal

    2011-12-01

    Full Text Available Article is devoted features of life cycle of mobile devices. The article highlighted a number of disadvantages associated with managing the life cycle of the product. Disadvantages include the orientation is not on the quality of mobile devices and their design, the obsolescence of digital products. The article drew attention to the need for process improvement life cycle management of mobile devices. For since this type of product is now the most popular among the population, consumers are interested, first of all, quality, and only then, look good.

  13. Skin-inspired electronic devices

    Directory of Open Access Journals (Sweden)

    Alex Chortos

    2014-09-01

    Full Text Available Electronic devices that mimic the properties of skin have potential important applications in advanced robotics, prosthetics, and health monitoring technologies. Methods for measuring tactile and temperature signals have progressed rapidly due to innovations in materials and processing methods. Imparting skin-like stretchability to electronic devices can be accomplished by patterning traditional electronic materials or developing new materials that are intrinsically stretchable. The incorporation of sensing methods with transistors facilitates large-area sensor arrays. While sensor arrays have surpassed the properties of human skin in terms of sensitivity, time response, and device density, many opportunities remain for future development.

  14. Giant magneto-resistance devices

    CERN Document Server

    Hirota, Eiichi; Inomata, Koichiro

    2002-01-01

    This book deals with the application of giant magneto-resistance (GMR) effects to electronic devices. It will appeal to engineers and graduate students in the fields of electronic devices and materials. The main subjects are magnetic sensors with high resolution and magnetic read heads with high sensitivity, required for hard-disk drives with recording densities of several gigabytes. Another important subject is novel magnetic random-access memories (MRAM) with non-volatile non-destructive and radiation-resistant characteristics. Other topics include future GMR devices based on bipolar spin transistors, spin field-effect transistors (FETs) and double-tunnel junctions.

  15. Medical applications of magnet devices

    Energy Technology Data Exchange (ETDEWEB)

    Hale, J.R.

    1975-09-01

    The use of magnetic devices in medically-related applications has often been frustrated by insufficient magnetic force, or by an inappropriately designed device. Magnetic treatment systems are discussed generally, and two systems are described in detail. First, a superconducting magnet, with integral orientation system, intended for use in intravascular catheter guidance is described. The maximum field and gradient produced by this solenoid are 20,000 Oe, and 2250 Oe/cm, respectively. The system is both powerful and easy to use, by virtue of its completely portable design. The second is a magnetic traction device which has been successfully employed in the treatment of esophageal atresia.

  16. Streamline-based microfluidic device

    Science.gov (United States)

    Tai, Yu-Chong (Inventor); Zheng, Siyang (Inventor); Kasdan, Harvey (Inventor)

    2013-01-01

    The present invention provides a streamline-based device and a method for using the device for continuous separation of particles including cells in biological fluids. The device includes a main microchannel and an array of side microchannels disposed on a substrate. The main microchannel has a plurality of stagnation points with a predetermined geometric design, for example, each of the stagnation points has a predetermined distance from the upstream edge of each of the side microchannels. The particles are separated and collected in the side microchannels.

  17. Arrhythmia management after device removal.

    Science.gov (United States)

    Nishii, Nobuhiro

    2016-08-01

    Arrhythmic management is needed after removal of cardiac implantable electronic devices (CIEDs). Patients completely dependent on CIEDs need temporary device back-up until new CIEDs are implanted. Various methods are available for device back-up, and the appropriate management varies among patients. The duration from CIED removal to implantation of a new CIED also differs among patients. Temporary pacing is needed for patients with bradycardia, a wearable cardioverter defibrillator (WCD) or catheter ablation is needed for patients with tachyarrhythmia, and sequential pacing is needed for patients dependent on cardiac resynchronization therapy. The present review focuses on arrhythmic management after CIED removal. PMID:27588151

  18. 21 CFR 801.109 - Prescription devices.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Prescription devices. 801.109 Section 801.109 Food... DEVICES LABELING Exemptions From Adequate Directions for Use § 801.109 Prescription devices. A device... direct the use of such device, and hence for which “adequate directions for use” cannot be...

  19. 16 CFR 1507.8 - Wheel devices.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Wheel devices. 1507.8 Section 1507.8... FIREWORKS DEVICES § 1507.8 Wheel devices. Drivers in fireworks devices commonly known as “wheels” shall be securely attached to the device so that they will not come loose in transportation, handling, and...

  20. Developing Linux kernel space device driver

    Institute of Scientific and Technical Information of China (English)

    Zheng Wei; Wang Qinruo; Wu Naiyou

    2003-01-01

    This thesis introduces how to develop kernel level device drivers on Linux platform in detail. On the basis of comparing proc file system with dev file system, we choose PCI devices and USB devices as instances to introduce the method of writing device drivers for character devices by using these two file systems.

  1. Handling device for stud tensioner

    International Nuclear Information System (INIS)

    The handling device for a stud tensioner machine used by example for fixing the reactor vessel head has an extension module, joining elements and means for displacement in vertical and horizontal axis

  2. Integrated Ultrasonic-Photonic Devices

    DEFF Research Database (Denmark)

    Barretto, Elaine Cristina Saraiva

    This thesis deals with the modeling, design, fabrication and characterization of integrated ultrasonic-photonic devices, with particular focus on the use of standard semiconductor materials such as GaAs and silicon. The devices are based on the use of guided acoustic waves to modulate the light...... in channel waveguides and Mach-Zehnder interferometers. Numerical models are developed based on the finite element method, and applied to several scenarios, such as optimization of the geometrical parameters of waveguides, use of slow light in photonic crystal waveguides and use of Lamb waves in membranized...... systems, all in search for paths to improve acousto-optic interaction. Some of the solutions proposed lead to enhancements of up to two orders of magnitude in the eciency of the device. The main aspects related to the design of the devices are discussed, including single-mode guidance, optical coupling...

  3. #DDOD: Establishment Registration & Device Listing

    Data.gov (United States)

    U.S. Department of Health & Human Services — SUMMARY DDOD use case to request means on consolidating multiple data sources (MDR, PMA, 510(k), R&L) in order to build a list of all marketed medical devices....

  4. Thermoelectric Devices Advance Thermal Management

    Science.gov (United States)

    2007-01-01

    Thermoelectric (TE) devices heat, cool, and generate electricity when a temperature differential is provided between the two module faces. In cooperation with NASA, Chico, California-based United States Thermoelectric Consortium Inc. (USTC) built a gas emissions analyzer (GEA) for combustion research. The GEA precipitated hydrocarbon particles, preventing contamination that would hinder precise rocket fuel analysis. The USTC research and design team uses patent-pending dimple, pin-fin, microchannel and microjet structures to develop and design heat dissipation devices on the mini-scale level, which not only guarantee high performance of products, but also scale device size from 1 centimeter to 10 centimeters. USTC continues to integrate the benefits of TE devices in its current line of thermal management solutions and has found the accessibility of NASA technical research to be a valuable, sustainable resource that has continued to positively influence its product design and manufacturing

  5. Nanomechanical Water Purification Device Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Seldon Laboratories, LLC, proposes a lightweight, low-pressure water purification device that harnesses the unique properties of carbon nanotubes and will operate...

  6. Polymer electronic devices and materials.

    Energy Technology Data Exchange (ETDEWEB)

    Schubert, William Kent; Baca, Paul Martin; Dirk, Shawn M.; Anderson, G. Ronald; Wheeler, David Roger

    2006-01-01

    Polymer electronic devices and materials have vast potential for future microsystems and could have many advantages over conventional inorganic semiconductor based systems, including ease of manufacturing, cost, weight, flexibility, and the ability to integrate a wide variety of functions on a single platform. Starting materials and substrates are relatively inexpensive and amenable to mass manufacturing methods. This project attempted to plant the seeds for a new core competency in polymer electronics at Sandia National Laboratories. As part of this effort a wide variety of polymer components and devices, ranging from simple resistors to infrared sensitive devices, were fabricated and characterized. Ink jet printing capabilities were established. In addition to promising results on prototype devices the project highlighted the directions where future investments must be made to establish a viable polymer electronics competency.

  7. Preventing the radiological dispersal device

    International Nuclear Information System (INIS)

    The paper discusses the IAEA plan of action to protect against nuclear terrorism, the nature of the threat of a radiological dispersal device, international instruments for the prevention of nuclear terrorism, recent progress and perspectives for future action. (author)

  8. Nanomechanical Water Purification Device Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Seldon Laboratories, LLC, proposes a lightweight, low-pressure water filtration device that harnesses the unique properties of nanoparticles to destroy or remove...

  9. Colour Reproduction on Tablet Devices

    OpenAIRE

    Vladimir Zorić; Igor Karlović

    2014-01-01

    With the advent of Internet and mobile devices client services and other print production are migrating more and more to online platforms. In a recent technology changeover it is obvious that there is growing number of printers as well need from the customers for the print service providers to expand their business to online and mobile platforms. With this technological transition there are some open questions regarding the possibilities of using the tablet devices for colour soft proofing an...

  10. Piezo-phototronic effect devices

    Science.gov (United States)

    Wang, Zhong L.; Yang, Qing

    2013-09-10

    A semiconducting device includes a piezoelectric structure that has a first end and an opposite second end. A first conductor is in electrical communication with the first end and a second conductor is in electrical communication with the second end so as to form an interface therebetween. A force applying structure is configured to maintain an amount of strain in the piezoelectric member sufficient to generate a desired electrical characteristic in the semiconducting device.

  11. Amorphous silicon based betavoltaic devices

    OpenAIRE

    Wyrsch, N; Riesen, Y.; Franco, A; S. Dunand; Kind, H.; Schneider, S.; Ballif, C.

    2013-01-01

    Hydrogenated amorphous silicon betavoltaic devices are studied both by simulation and experimentally. Devices exhibiting a power density of 0.1 μW/cm2 upon Tritium exposure were fabricated. However, a significant degradation of the performance is taking place, especially during the first hours of the exposure. The degradation behavior differs from sample to sample as well as from published results in the literature. Comparisons with degradation from beta particles suggest an effect of tritium...

  12. Operating systems for mobile devices

    OpenAIRE

    Hroch, Jiří

    2012-01-01

    This bachelor thesis is focused on operating systems for mobile devices. The first part is listed first term PC operating system and the most common types of these systems. The operating systems for mobile devices are now chosen the most widely used platforms, which are subsequently described. There is something about their history, development, and are given different versions of these systems.In the second part of this work is compared with popular operating systems today, Android and iOS. ...

  13. Biomedical devices and their applications

    CERN Document Server

    2004-01-01

    This volume introduces readers to the basic concepts and recent advances in the field of biomedical devices. The text gives a detailed account of novel developments in drug delivery, protein electrophoresis, estrogen mimicking methods and medical devices. It also provides the necessary theoretical background as well as describing a wide range of practical applications. The level and style make this book accessible not only to scientific and medical researchers but also to graduate students.

  14. Metal semiconductor contacts and devices

    CERN Document Server

    Cohen, Simon S; Einspruch, Norman G

    1986-01-01

    VLSI Electronics Microstructure Science, Volume 13: Metal-Semiconductor Contacts and Devices presents the physics, technology, and applications of metal-semiconductor barriers in digital integrated circuits. The emphasis is placed on the interplay among the theory, processing, and characterization techniques in the development of practical metal-semiconductor contacts and devices.This volume contains chapters that are devoted to the discussion of the physics of metal-semiconductor interfaces and its basic phenomena; fabrication procedures; and interface characterization techniques, particularl

  15. Radiation effects in optoelectronic devices

    International Nuclear Information System (INIS)

    Purpose of this report is to provide not only a summary of radiation damage studies at Sandia National Laboratories, but also of those in the literature on the components of optoelectronic systems: light emitting diodes (LEDs), laser diodes, photodetectors, optical fibers, and optical isolators. This review of radiation damage in optoelectronic components is structured according to device type. In each section, a brief discussion of those device properties relevant to radiation effects is given

  16. PKM Mechatronic Clamping Adaptive Device

    OpenAIRE

    Alberto Borboni; Francesco Aggogeri; Angelo Merlo; Nicola Pellegrini; Cinzia Amici

    2015-01-01

    This study proposes a novel adaptive fixturing device based on active clamping systems for smart micropositioning of thin-walled precision parts. The modular architecture and the structure flexibility make the system suitable for various industrial applications. The proposed device is realized as a Parallel Kinematic Machine (PKM), opportunely sensorized and controlled, able to perform automatic error-free workpiece clamping procedures, drastically reducing the overall fixturing set-up time. ...

  17. Lightweight cryptography for constrained devices

    DEFF Research Database (Denmark)

    Alippi, Cesare; Bogdanov, Andrey; Regazzoni, Francesco

    2014-01-01

    Lightweight cryptography is a rapidly evolving research field that responds to the request for security in resource constrained devices. This need arises from crucial pervasive IT applications, such as those based on RFID tags where cost and energy constraints drastically limit the solution...... complexity, with the consequence that traditional cryptography solutions become too costly to be implemented. In this paper, we survey design strategies and techniques suitable for implementing security primitives in constrained devices....

  18. Trustworthy execution on mobile devices

    CERN Document Server

    Vasudevan, Amit; Newsome, James

    2013-01-01

    This brief considers the various stakeholders in today's mobile device ecosystem, and analyzes why widely-deployed hardware security primitives on mobile device platforms are inaccessible to application developers and end-users. Existing proposals are also evaluated for leveraging such primitives, and proves that they can indeed strengthen the security properties available to applications and users, without reducing the properties currently enjoyed by OEMs and network carriers. Finally, this brief makes recommendations for future research that may yield practical and deployable results.

  19. High speed serdes devices and applications

    CERN Document Server

    Stauffer, David R; Sorna, Michael A; Dramstad, Kent; Ogilvie, Clarence Rosser; Amanullah, Mohammad; Rockrohr, James Donald

    2008-01-01

    Offers an understanding of the features and functions typically found on HSS devices. This book explains how these HSS devices are used in protocol applications and the analysis which must be performed to use such HSS devices.

  20. 77 FR 60720 - Certain Electronic Devices, Including Wireless Commmunication Devices, Portable Music and Data...

    Science.gov (United States)

    2012-10-04

    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Certain Electronic Devices, Including Wireless Commmunication Devices, Portable Music and Data... infringing electronic devices, including wireless communication devices, portable music and data...

  1. Light-Emitting Devices with Conjugated Polymers

    Directory of Open Access Journals (Sweden)

    Xian-Yu Deng

    2011-03-01

    Full Text Available This article introduces a previous study and tremendous progress in basic theoretical modeling, material developments and device engineering for polymer light-emitting devices (PLEDs.

  2. 16 CFR 1507.9 - Toy smoke devices and flitter devices.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Toy smoke devices and flitter devices. 1507... SUBSTANCES ACT REGULATIONS FIREWORKS DEVICES § 1507.9 Toy smoke devices and flitter devices. (a) Toy smoke devices shall be so constructed that they will neither burst nor produce external flame (excluding...

  3. Resource management for device-to-device underlay communication

    CERN Document Server

    Song, Lingyang; Xu, Chen

    2013-01-01

    Device-to-Device (D2D) communication will become a key feature supported by next generation cellular networks, a topic of enormous importance to modern communication. Currently, D2D serves as an underlay to the cellular network as a means to increase spectral efficiency. Although D2D communication brings large benefits in terms of system capacity, it also causes interference as well as increased computation complexity to cellular networks as a result of spectrum sharing. Thus, efficient resource management must be performed to guarantee a target performance level of cellular communication.This

  4. An Overview of Biofield Devices.

    Science.gov (United States)

    Muehsam, David; Chevalier, Gaétan; Barsotti, Tiffany; Gurfein, Blake T

    2015-11-01

    Advances in biophysics, biology, functional genomics, neuroscience, psychology, psychoneuroimmunology, and other fields suggest the existence of a subtle system of "biofield" interactions that organize biological processes from the subatomic, atomic, molecular, cellular, and organismic to the interpersonal and cosmic levels. Biofield interactions may bring about regulation of biochemical, cellular, and neurological processes through means related to electromagnetism, quantum fields, and perhaps other means of modulating biological activity and information flow. The biofield paradigm, in contrast to a reductionist, chemistry-centered viewpoint, emphasizes the informational content of biological processes; biofield interactions are thought to operate in part via low-energy or "subtle" processes such as weak, nonthermal electromagnetic fields (EMFs) or processes potentially related to consciousness and nonlocality. Biofield interactions may also operate through or be reflected in more well-understood informational processes found in electroencephalographic (EEG) and electrocardiographic (ECG) data. Recent advances have led to the development of a wide variety of therapeutic and diagnostic biofield devices, defined as physical instruments best understood from the viewpoint of a biofield paradigm. Here, we provide a broad overview of biofield devices, with emphasis on those devices for which solid, peer-reviewed evidence exists. A subset of these devices, such as those based upon EEG- and ECG-based heart rate variability, function via mechanisms that are well understood and are widely employed in clinical settings. Other device modalities, such a gas discharge visualization and biophoton emission, appear to operate through incompletely understood mechanisms and have unclear clinical significance. Device modes of operation include EMF-light, EMF-heat, EMF-nonthermal, electrical current, vibration and sound, physical and mechanical, intentionality and nonlocality, gas and

  5. An Overview of Biofield Devices.

    Science.gov (United States)

    Muehsam, David; Chevalier, Gaétan; Barsotti, Tiffany; Gurfein, Blake T

    2015-11-01

    Advances in biophysics, biology, functional genomics, neuroscience, psychology, psychoneuroimmunology, and other fields suggest the existence of a subtle system of "biofield" interactions that organize biological processes from the subatomic, atomic, molecular, cellular, and organismic to the interpersonal and cosmic levels. Biofield interactions may bring about regulation of biochemical, cellular, and neurological processes through means related to electromagnetism, quantum fields, and perhaps other means of modulating biological activity and information flow. The biofield paradigm, in contrast to a reductionist, chemistry-centered viewpoint, emphasizes the informational content of biological processes; biofield interactions are thought to operate in part via low-energy or "subtle" processes such as weak, nonthermal electromagnetic fields (EMFs) or processes potentially related to consciousness and nonlocality. Biofield interactions may also operate through or be reflected in more well-understood informational processes found in electroencephalographic (EEG) and electrocardiographic (ECG) data. Recent advances have led to the development of a wide variety of therapeutic and diagnostic biofield devices, defined as physical instruments best understood from the viewpoint of a biofield paradigm. Here, we provide a broad overview of biofield devices, with emphasis on those devices for which solid, peer-reviewed evidence exists. A subset of these devices, such as those based upon EEG- and ECG-based heart rate variability, function via mechanisms that are well understood and are widely employed in clinical settings. Other device modalities, such a gas discharge visualization and biophoton emission, appear to operate through incompletely understood mechanisms and have unclear clinical significance. Device modes of operation include EMF-light, EMF-heat, EMF-nonthermal, electrical current, vibration and sound, physical and mechanical, intentionality and nonlocality, gas and

  6. Radioactive gaseous waste processing device

    International Nuclear Information System (INIS)

    In a radioactive gaseous waste processing device, a dehumidifier in which a lot of hollow thread membranes are bundled and assembled is disposed instead of a dehumidifying cooling device and a dehumidifying tower. The dehumidifier comprises a main body, a great number of hollow thread membranes incorporated in the main body, a pair of fixing members for bundling and fixing both ends of the hollow thread membranes, a pair of caps for allowing the fixing members to pass through and fixing them on both ends of the main body, an off gas flowing pipe connected to one of the caps, a gas exhaustion pipe connected to the other end of the cap and a moisture removing pipeline connected to the main body. A flowrate control valve is connected to the moisture removing pipeline, and the other end of the moisture removing pipeline is connected between a main condensator and an air extraction device. Then, cooling and freezing devices using freon are no more necessary, and since the device uses the vacuum of the main condensator as a driving source and does not use dynamic equipments, labors for the maintenance is greatly reduced to improve economical property. The facilities are reduced in the size thereby enabling to use space effectively. (N.H.)

  7. Survey of cryogenic semiconductor devices

    Energy Technology Data Exchange (ETDEWEB)

    Talarico, L.J.; McKeever, J.W.

    1996-04-01

    Improved reliability and electronic performance can be achieved in a system operated at cryogenic temperatures because of the reduction in mechanical insult and in disruptive effects of thermal energy on electronic devices. Continuing discoveries of new superconductors with ever increasing values of T{sub c} above that of liquid nitrogen temperature (LNT) have provided incentive for developing semiconductor electronic systems that may also operate in the superconductor`s liquid nitrogen bath. Because of the interest in high-temperature superconductor (HTS) devices, liquid nitrogen is the cryogen of choice and LNT is the temperature on which this review is focused. The purpose of this survey is to locate and assemble published information comparing the room temperature (298 K), performance of commercially available conventional and hybrid semiconductor device with their performance at LNT (77K), to help establish their candidacy as cryogenic electronic devices specifically for use at LNT. The approach to gathering information for this survey included the following activities. Periodicals and proceedings were searched for information on the behavior of semiconductor devices at LNT. Telephone calls were made to representatives of semiconductor industries, to semiconductor subcontractors, to university faculty members prominent for their research in the area of cryogenic semiconductors, and to representatives of the National Aeronautics and Space Administration (NASA) and NASA subcontractors. The sources and contacts are listed with their responses in the introduction, and a list of references appears at the end of the survey.

  8. A TOUCH-SENSITIVE DEVICE

    DEFF Research Database (Denmark)

    2009-01-01

    propagating towards a specific point of the detector array is prevented from being incident upon the specific point of the detector array when an object contacts a touch-sensitive surface of the touch-sensitive waveguide at a corresponding specific contact point.......The present invention relates to an optical touch-sensitive device and a method of determining a position and determining a position change of an object contacting an optical touch sensitive device. In particular, the present invention relates to an optical touch pad and a method of determining...... a position and determining a position change of an object contacting an optical touch pad. A touch-sensitive device, according to the present invention may comprise a light source, a touch- sensitive waveguide, a detector array, and a first light redirecting member, wherein at least a part of the light...

  9. Self-forming nanoscale devices

    Directory of Open Access Journals (Sweden)

    Lars Samuelson

    2003-10-01

    The top-down approach limits the dimensions of devices to what is technically achievable using lithography. This is the means by which patterns can be drawn, either in stone as the Vikings did when they carved messages into granite, or into Si as the electronics industry does today to build integrated circuits. Lithographic techniques can create device features as narrow as 130 nm and the industry sees the road ahead pretty well drawn up for line-widths down to ∼50 nm. This continued progress does not come without a price; the cost of new fabs is growing extremely fast, at a pace that may limit continued progress, simply because devices and circuits become too expensive to be economically viable.

  10. Linerless label device and method

    KAUST Repository

    Binladen, Abdulkari

    2016-01-14

    This apparatus and method for applying a linerless label to an end user product includes a device with a printer for printing on a face surface of a linerless label, and a release coat applicator for applying a release coat to the face surface of the label; another device including an unwinder unit (103) to unwind a roll of printed linerless label; a belt (108); a glue applicator (102) for applying glue to the belt; a nip roller (106) for contacting and applying pressure to the face surface of the linerless label such that the glue on the belt transfers to the back surface of the linerless label; at least one slitting knife 105) positioned downstream the belt and a rewinder unit (104) positioned downstream the slitting knife; and a third device which die cuts and applies the linerless label to an end user object.

  11. Advanced Mechatronics and MEMS Devices

    CERN Document Server

    2013-01-01

    Advanced Mechatronics and MEMS Devicesdescribes state-of-the-art MEMS devices and introduces the latest technology in electrical and mechanical microsystems. The evolution of design in microfabrication, as well as emerging issues in nanomaterials, micromachining, micromanufacturing and microassembly are all discussed at length in this volume. Advanced Mechatronics also provides a reader with knowledge of MEMS sensors array, MEMS multidimensional accelerometer, artificial skin with imbedded tactile components, as well as other topics in MEMS sensors and transducers. The book also presents a number of topics in advanced robotics and an abundance of applications of MEMS in robotics, like reconfigurable modular snake robots, magnetic MEMS robots for drug delivery and flying robots with adjustable wings, to name a few. This book also: Covers the fundamentals of advanced mechatronics and MEMS devices while also presenting new state-of-the-art methodology and technology used in the application of these devices Prese...

  12. Survey of hydrogen monitoring devices

    International Nuclear Information System (INIS)

    Presented are results of a survey of commercially available monitoring devices suitable for hydrogen detection in the secondary containment vessel of a nuclear power plant during the post postulated accident period. Available detectors were grouped into the following five classes: combustion, solid state, electrochemical, thermal conductivity, and absorption. The performance of most available sensors is likely to deteriorate when exposed to the postulated conditions which include moisture, which could be at high temperature, and radioactive noncondensibles. Of the commercial devices, those using metallic filament thermal conductivity detectors seem least susceptible to performance change. Absorption detectors are best suited for this monitoring task but the only available device is designed for pipeline corrosion assessment. Initiation of experimental study to assess apparent deficiencies of commercial detectors is recommended. Also recommended is an analytical/experimental effort to determine the optimum detector array for monitoring in the secondary containment vessels

  13. Fabrication of Green Electroluminescent Devices

    Institute of Scientific and Technical Information of China (English)

    高德青; 黄春辉; 奎热西; 刘凤琴

    2002-01-01

    A gadolinium ternary complex, tris(1-phenyl-3-methyl-4-isobutyryl-5-pyrazolone) (2, 2′-dipyridyl) gadolinium Gd(PMIP)3(Bipy) was synthesized and used as a light emitting material in the organic electroluminescent devices. The devices exhibited the green electroluminescent (EL) emission peaking at 513 nm, originating from the Gd(PMIP)3(Bipy). By improving the configuration, the device with a structure of ITO/poly(N-vinylcarbazole) (PVK) (40 nm)/Gd(PMIP)3(Bipy) (40 nm)/tris (8-hydroxyquinoline) aluminum (ALQ) (40 nm)/Mg∶Ag(200 nm)/Ag(100 nm) showed higher performance and a maximum luminance of 340 cd*m-2 at 18 V.

  14. Microelectroporation device for genomic screening

    Energy Technology Data Exchange (ETDEWEB)

    Perroud, Thomas D.; Renzi, Ronald F.; Negrete, Oscar; Claudnic, Mark R.

    2014-09-09

    We have developed an microelectroporation device that combines microarrays of oligonucleotides, microfluidic channels, and electroporation for cell transfection and high-throughput screening applications (e.g. RNA interference screens). Microarrays allow the deposition of thousands of different oligonucleotides in microscopic spots. Microfluidic channels and microwells enable efficient loading of cells into the device and prevent cross-contamination between different oligonucleotides spots. Electroporation allows optimal transfection of nucleic acids into cells (especially hard-to-transfect cells such as primary cells) by minimizing cell death while maximizing transfection efficiency. This invention has the advantage of a higher throughput and lower cost, while preventing cross-contamination compared to conventional screening technologies. Moreover, this device does not require bulky robotic liquid handling equipment and is inherently safer given that it is a closed system.

  15. Digital Devices and Distracted Doctoring.

    Science.gov (United States)

    Dossey, Garry

    2015-04-01

    During the past twenty years a digital sea change has affected our world. Digital devices have changed the way we live and especially the way we work in our professions. As dentists, we are able to work with far greater accuracy and precision than ever before; we would be foolish not to embrace these advances. But, as is often the case with rapid cultural changes, we need to be aware of the possibility of unintended consequences that may accompany this revolution. Sound scientific studies are beginning to warn of the psychological and physiological problems of overuse of digital devices in our daily lives. We should remember that these devices are neutral. It is up to each of us to use them in ways that enhance patient care. PMID:26234105

  16. High-power active devices

    CERN Document Server

    Carroll, E

    2006-01-01

    Very high-power (HP) electronics represents a small part of the electronics market. In semiconductor terms, HP represents a world device market of 600 million euros out of a total 200 billion euros for all semiconductors—a mere 0.3 per cent. At the multi-megawatt spectral end, the numbers are even smaller, so that it is quite common for electronics engineers to be unaware of developments in Very High Power (VHP). In this presentation we discuss the categories of VHP active devices, the basic topologies in which they operate, and the trend towards higher voltage and current. New press-pack technologies are introduced and the salient differences between Insulated Gate Bipolar Transistors (IGBTs) and Integrated Gate Commutated Thyristors (IGCTs) are compared. Finally, recent developments in turn-off ratings for both these devices are presented.

  17. Colour Reproduction on Tablet Devices

    Directory of Open Access Journals (Sweden)

    Vladimir Zorić

    2014-07-01

    Full Text Available With the advent of Internet and mobile devices client services and other print production are migrating more and more to online platforms. In a recent technology changeover it is obvious that there is growing number of printers as well need from the customers for the print service providers to expand their business to online and mobile platforms. With this technological transition there are some open questions regarding the possibilities of using the tablet devices for colour soft proofing and other colour related operations. As a display devices on a hardware level there are large similarities with the desktop display devices but the operating systems which are driving them are not yet colour smart. There have been some initial attempts to characterize the colour reproduction on this type of devices and find a possibility of using them not just for information content but also for colour managed content. In this study we have tested several tablets (Apple iPad2,Asus Transformer TF101, Samsung Galaxy Tab 1 with different display and OS technology and tested a software which is intended for colour managed viewing of the reproduction. We have measured the colour reproduction of the tablets with the digital version of the GretagMacbeth ColorChecker card and have calculated the colour differences between the colour chart data and the displayed data. We have calibrated the Ipad2 with the only existing colour management tool the Spyder Gallery and we have also tested the chart display with and without the colour correction of the software. We have found that there are differences in the colour reproduction of the display technologies and that the possibilities of a real colour managed workflow has yet to be resolved on the OS level of tablet and mobile devices

  18. Semiconductor-based, large-area, flexible, electronic devices

    Science.gov (United States)

    Goyal, Amit

    2011-03-15

    Novel articles and methods to fabricate the same resulting in flexible, large-area, triaxially textured, single-crystal or single-crystal-like, semiconductor-based, electronic devices are disclosed. Potential applications of resulting articles are in areas of photovoltaic devices, flat-panel displays, thermophotovoltaic devices, ferroelectric devices, light emitting diode devices, computer hard disc drive devices, magnetoresistance based devices, photoluminescence based devices, non-volatile memory devices, dielectric devices, thermoelectric devices and quantum dot laser devices.

  19. Price transparency for medical devices.

    Science.gov (United States)

    Pauly, Mark V; Burns, Lawton R

    2008-01-01

    Hospital buyers of medical devices contract with manufacturers with market power that sell differentiated products. The medical staff strongly influences hospitals' choice of devices. Sellers have sought to limit disclosure of transaction prices. Policy-makers have proposed legislation mandating disclosure, in the interest of greater transparency. We discuss why a manufacturer might charge different prices to different hospitals, the role that secrecy plays, and the consequences of secrecy versus disclosure. We argue that hospital-physician relationships are key to understanding what manufacturers gain from price discrimination. Price disclosure can catalyze a restructuring of those relationships, which, in turn, can improve hospital bargaining. PMID:18997210

  20. Materials for energy conversion devices

    CERN Document Server

    Sorrell, C C; Sugihara, S

    2005-01-01

    As the finite capacity and pollution problems of fossil fuels grow more pressing, new sources of more sustainable energy are being developed. Materials for energy conversion devices summarises the key research on new materials which can be used to generate clean and renewable energy or to help manage problems from existing energy sources. The book discusses the range of materials that can be used to harness and convert solar energy in particular, including the properties of oxide materials and their use in producing hydrogen fuel. It covers thermoelectric materials and devices for power genera

  1. Medical devices and human engineering

    CERN Document Server

    Bronzino, Joseph D

    2014-01-01

    Known as the bible of biomedical engineering, The Biomedical Engineering Handbook, Fourth Edition, sets the standard against which all other references of this nature are measured. As such, it has served as a major resource for both skilled professionals and novices to biomedical engineering.Medical Devices and Human Engineering, the second volume of the handbook, presents material from respected scientists with diverse backgrounds in biomedical sensors, medical instrumentation and devices, human performance engineering, rehabilitation engineering, and clinical engineering.More than three doze

  2. Flexible spintronic devices on Kapton

    DEFF Research Database (Denmark)

    Bedoya-Pinto, Amilcar; Donolato, Marco; Gobbi, Marco;

    2014-01-01

    Magnetic tunnel junctions and nano-sized domain-wall conduits have been fabricated on the flexible substrate Kapton. Despite the delicate nature of tunneling barriers and zig-zag shaped nanowires, the devices show an outstanding integrity and robustness upon mechanical bending. High values...... of bending angle (r = 5 mm) have been achieved without degradation of the device performance, reaching room-temperature tunneling magnetoresistance ratios of 12% in bended Co/Al2O3/NiFe junctions. In addition, a suitable route to pattern high-quality nanostructures directly on the polyimide surface...

  3. Medical Devices; General Hospital and Personal Use Devices; Classification of the Ultraviolet Radiation Chamber Disinfection Device. Final order.

    Science.gov (United States)

    2015-11-20

    The Food and Drug Administration (FDA or the Agency) is classifying the ultraviolet (UV) radiation chamber disinfection device into class II (special controls). The special controls that will apply to the device are identified in this order and will be part of the codified language for the UV radiation chamber disinfection device classification. The Agency is classifying the device into class II (special controls) in order to provide a reasonable assurance of safety and effectiveness of the device. PMID:26595943

  4. 21 CFR 821.4 - Imported devices.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Imported devices. 821.4 Section 821.4 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES MEDICAL DEVICE TRACKING REQUIREMENTS General Provisions § 821.4 Imported devices. For purposes of...

  5. 30 CFR 75.815 - Disconnect devices.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Disconnect devices. 75.815 Section 75.815... Longwalls § 75.815 Disconnect devices. (a) The section power center must be equipped with a main disconnecting device installed to deenergize all cables extending to longwall equipment when the device is...

  6. 33 CFR 154.525 - Monitoring devices.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Monitoring devices. 154.525... Monitoring devices. The COTP may require the facility to install monitoring devices if the installation of monitoring devices at the facility would significantly limit the size of a discharge of oil or...

  7. 49 CFR 221.14 - Marking devices.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Marking devices. 221.14 Section 221.14..., DEPARTMENT OF TRANSPORTATION REAR END MARKING DEVICE-PASSENGER, COMMUTER AND FREIGHT TRAINS Marking Devices § 221.14 Marking devices. (a) As prescribed in § 221.13, passenger, commuter and freight trains shall...

  8. 14 CFR 23.459 - Special devices.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Special devices. 23.459 Section 23.459 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS... Devices § 23.459 Special devices. The loading for special devices using aerodynamic surfaces (such...

  9. 47 CFR 15.103 - Exempted devices.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Exempted devices. 15.103 Section 15.103 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES Unintentional Radiators § 15.103 Exempted devices. The following devices are subject only to the general conditions of operation in §§...

  10. 40 CFR 89.107 - Defeat devices.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Defeat devices. 89.107 Section 89.107... Provisions § 89.107 Defeat devices. (a) An engine may not be equipped with a defeat device. (b) For purposes of this section, “defeat device” means any device, system, or element of design which...

  11. Electronic Payments using Mobile Communication Devices

    NARCIS (Netherlands)

    Waaij, B.D. van der; Siljee, B.I.J.; Broekhuijsen, B.J.; Ponsioen, C.; Maas, A.; Aten, R.M.; Hoepman, J.H.; Loon, J.H. van; Smit, M.

    2009-01-01

    A method of making a payment uses a first mobile communication device (1) and a second mobile communication device (2), each mobile communication device being provided with a respective near field communication unit (11, 21) and at least one of the mobile communication devices being provided with an

  12. Implantable biomedical devices on bioresorbable substrates

    Science.gov (United States)

    Rogers, John A; Kim, Dae-Hyeong; Omenetto, Fiorenzo; Kaplan, David L; Litt, Brian; Viventi, Jonathan; Huang, Yonggang; Amsden, Jason

    2014-03-04

    Provided herein are implantable biomedical devices, methods of administering implantable biomedical devices, methods of making implantable biomedical devices, and methods of using implantable biomedical devices to actuate a target tissue or sense a parameter associated with the target tissue in a biological environment. Each implantable biomedical device comprises a bioresorbable substrate, an electronic device having a plurality of inorganic semiconductor components supported by the bioresorbable substrate, and a barrier layer encapsulating at least a portion of the inorganic semiconductor components. Upon contact with a biological environment the bioresorbable substrate is at least partially resorbed, thereby establishing conformal contact between the implantable biomedical device and the target tissue in the biological environment.

  13. Mechatronic Device for Elbow Rehabilitation

    Directory of Open Access Journals (Sweden)

    Fausti Davide

    2016-01-01

    Full Text Available This work proposes a mechatronic device for elbow rehabilitation. The realized therapy is based on continuous passive motion. A prototype was realized and design and dimensioning is here presented. Preliminary tests will be performed on non-pathological subjects to allow clinical experiments.

  14. Fabrication of Optical Fiber Devices

    Science.gov (United States)

    Andres, Miguel V.

    In this paper we present the main research activities of the Laboratorio de Fibras Opticas del Instituto de Ciencia de los Materiales de la Universidad de Valencia. We show some of the main results obtained for devices based on tapered fibers, fiber Bragg gratings, acousto-optic effects and photonic crystal fibers.

  15. Stretchable Hydrogel Electronics and Devices.

    Science.gov (United States)

    Lin, Shaoting; Yuk, Hyunwoo; Zhang, Teng; Parada, German Alberto; Koo, Hyunwoo; Yu, Cunjiang; Zhao, Xuanhe

    2016-06-01

    Stretchable hydrogel electronics and devices are designed by integrating stretchable conductors, functional chips, drug-delivery channels, and reservoirs into stretchable, robust, and biocompatible hydrogel matrices. Novel applications include a smart wound dressing capable of sensing the temperatures of various locations on the skin, delivering different drugs to these locations, and subsequently maintaining sustained release of drugs.

  16. Ultrafast Spectroscopy of Semiconductor Devices

    DEFF Research Database (Denmark)

    Borri, Paola; Langbein, Wolfgang; Hvam, Jørn Marcher

    1999-01-01

    In this work we present an experimental technique for investigating ultrafast carrier dynamics in semiconductor optical amplifiers at room temperature. These dynamics, influenced by carrier heating, spectral hole-burning and two-photon absorption, are very important for device applications in inf...

  17. Separating Device for solid Particles

    NARCIS (Netherlands)

    De Jong, T.P.R.; Kattentidt, H.U.R.; Schokker, E.A.

    2001-01-01

    The invention relates to a separating device for solid fragments, comprising a conveyor belt for supplying the fragments, at least one sensor for detecting the fragments, and an ejector for dislodging the fragments from the belt. The ejector is embodied as mechanical impulse-transmitting organ opera

  18. New Clothing for Handheld Devices

    Science.gov (United States)

    Roman, Harry T.

    2013-01-01

    Clothing is influenced by many factors, trends, and social happenings. Much of what is worn today had utilitarian roots in the past. In the activitiy presented in this article, students will have the opportunity to redesign clothing for new trends, in this case, the explosion of handheld electronic devices.

  19. Terahertz Semiconductor Quantum Well Devices

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    For eventually providing terahertz science with compact and convenient devices,terahertz (1~10THz) quantum-well photodetectors and quantum-cascade lasers are investigated. The design and projected detector performance are presented together with experimental results for several test devices,all working at photon energies below and around optical phonons. Background limited infrared performance (BLIP) operations are observed for all samples (three in total) ,designed for different wavelengths. BLIP temperatures of 17,13, and 12K are achieved for peak detection frequencies of 9.7THz(31μm) ,5.4THz(56μm) ,and 3.2THz(93μm) ,respectively. A set of THz quantum-cascade lasers with identical device parameters except for doping concentration is studied. The δ-doping density for each period varies from 3.2 × 1010 to 4. 8 × 1010cm-2. We observe that the lasing threshold current density increases monotonically with doping concentration. Moreover, the measurements for devices with different cavity lengths provide evidence that the free carrier absorption causes the waveguide loss also to increase monotonically. Interestingly the observed maximum lasing temperature is best at a doping density of 3.6 × 1010cm-2.

  20. Featured Invention: Laser Scaling Device

    Science.gov (United States)

    Dunn, Carol Anne

    2008-01-01

    In September 2003, NASA signed a nonexclusive license agreement with Armor Forensics, a subsidiary of Armor Holdings, Inc., for the laser scaling device under the Innovative Partnerships Program. Coupled with a measuring program, also developed by NASA, the unit provides crime scene investigators with the ability to shoot photographs at scale without having to physically enter the scene, analyzing details such as bloodspatter patterns and graffiti. This ability keeps the scene's components intact and pristine for the collection of information and evidence. The laser scaling device elegantly solved a pressing problem for NASA's shuttle operations team and also provided industry with a useful tool. For NASA, the laser scaling device is still used to measure divots or damage to the shuttle's external tank and other structures around the launchpad. When the invention also met similar needs within industry, the Innovative Partnerships Program provided information to Armor Forensics for licensing and marketing the laser scaling device. Jeff Kohler, technology transfer agent at Kennedy, added, "We also invited a representative from the FBI's special photography unit to Kennedy to meet with Armor Forensics and the innovator. Eventually the FBI ended up purchasing some units. Armor Forensics is also beginning to receive interest from DoD [Department of Defense] for use in military crime scene investigations overseas."

  1. Measuring verification device error rates

    International Nuclear Information System (INIS)

    A verification device generates a Type I (II) error when it recommends to reject (accept) a valid (false) identity claim. For a given identity, the rates or probabilities of these errors quantify random variations of the device from claim to claim. These are intra-identity variations. To some degree, these rates depend on the particular identity being challenged, and there exists a distribution of error rates characterizing inter-identity variations. However, for most security system applications we only need to know averages of this distribution. These averages are called the pooled error rates. In this paper the authors present the statistical underpinnings for the measurement of pooled Type I and Type II error rates. The authors consider a conceptual experiment, ''a crate of biased coins''. This model illustrates the effects of sampling both within trials of the same individual and among trials from different individuals. Application of this simple model to verification devices yields pooled error rate estimates and confidence limits for these estimates. A sample certification procedure for verification devices is given in the appendix

  2. Silicon Nano-Photonic Devices

    DEFF Research Database (Denmark)

    Pu, Minhao

    to microwave systems and biosensing devices. An ultra-low loss inverse taper coupler for interfacing silicon ridge waveguides and optical bers is introduced and insertion losses of less than 1 dB are achieved for both transverse-electric (TE) and transversemagnetic (TM) polarizations. Integrated...

  3. An active magnetic regenerator device

    DEFF Research Database (Denmark)

    2015-01-01

    A rotating active magnetic regenerator (AMR) device comprising two or more regenerator beds, a magnet arrangement and a valve arrangement. The valve arrangement comprises a plurality of valve elements arranged substantially immovably with respect to the regenerator beds along a rotational direction...

  4. Leading Edge Device Aerodynamic Optimization

    Directory of Open Access Journals (Sweden)

    Marius Gabriel COJOCARU

    2015-12-01

    Full Text Available Leading edge devices are conventionally used as aerodynamic devices that enhance performances during landing and in some cases during takeoff. The need to increase the efficiency of the aircrafts has brought the idea of maintaining as much as possible a laminar flow over the wings. This is possible only when the leading edge of the wings is free from contamination, therefore using the leading edge devices with the additional role of shielding during takeoff. Such a device based on the Krueger flap design is aerodynamically analyzed and optimized. The optimization comprises three steps: first, the positioning of the flap such that the shielding criterion is kept, second, the analysis of the flap size and third, the optimization of the flap shape. The first step is subject of a gradient based optimization process of the position described by two parameters, the position along the line and the deflection angle. For the third step the Adjoint method is used to gain insight on the shape of the Krueger flap that will extend the most the stall limit. All these steps have been numerically performed using Ansys Fluent and the results are presented for the optimized shape in comparison with the baseline configuration.

  5. Wavelength conversion techniques and devices

    DEFF Research Database (Denmark)

    Danielsen, Søren Lykke; Mikkelsen, Benny; Hansen, Peter Bukhave;

    1997-01-01

    interesting for use in WDM optical fibre networks. However, the perfect converter has probably not yet been fabricated and new techniques such as conversion relying on cross-absorption modulation in electro-absorption modulators might also be considered in pursue of effective conversion devices...

  6. Nanophotonic Devices for Optical Interconnect

    DEFF Research Database (Denmark)

    Van Thourhout, D.; Spuesens, T.; Selvaraja, S.K.;

    2010-01-01

    We review recent progress in nanophotonic devices for compact optical interconnect networks. We focus on microdisk-laser-based transmitters and discuss improved design and advanced functionality including all-optical wavelength conversion and flip-flops. Next we discuss the fabrication uniformity...

  7. Topology Optimization of Nanophotonic Devices

    DEFF Research Database (Denmark)

    Yang, Lirong

    This thesis explores the various aspects of utilizing topology optimization in designing nanophotonic devices. Either frequency-domain or time-domain methods is used in combination with the optimization algorithms, depending on various aims of the designing problems. The frequency-domain methods...

  8. Method of making optoelectric devices

    DEFF Research Database (Denmark)

    2012-01-01

    A method of preparing an optoelectric device, comprising: (a) providing a substrate on which is formed a first electrode layer; (b) forming an electron transport layer according to the following method: i) forming a film of a coating ink comprising zinc acetate in aqueous solution; ii) drying...

  9. High performance thermoelectric nanocomposite device

    Science.gov (United States)

    Yang, Jihui; Snyder, Dexter D.

    2011-10-25

    A thermoelectric device includes a nanocomposite material with nanowires of at least one thermoelectric material having a predetermined figure of merit, the nanowires being formed in a porous substrate having a low thermal conductivity and having an average pore diameter ranging from about 4 nm to about 300 nm.

  10. Feeding device for glossectomy patients.

    Science.gov (United States)

    Fleming, S M; Weaver, A W

    1983-04-01

    Instructions are provided for making a feeding spoon from a plastic syringe for use by patients who have had a glossectomy. This adaptation may be accomplished using only a hacksaw blade and sandpaper. Such a device may be indicated for patients who have had at least 60% of their tongue resected, but who are not at significant risk of aspiration. PMID:6838348

  11. Mobile Devices in the Classroom

    Science.gov (United States)

    Schachter, Ron

    2009-01-01

    As cell phones--with ever-expanding possibilities of texting, Web browsing, and game playing--have multiplied in recent years among teenagers and even preteens, so have the concerns of teachers and administrators about the distractions these devices can cause. A survey of students and parents earlier this year by the group Common Sense Media found…

  12. Predistortion control device and method, assembly including a predistortion control device

    OpenAIRE

    Kokkeler, André

    2009-01-01

    A predistortion control device (1). The device has a first predistortion control input connectable to a power amplifier output (21); a second predistortion control input (11) connectable to a signal contact of a predistortion device; and a predistortion control output (12) connectable to a control contact of the predistortion device. The predistortion control device (1) further includes a cross-correlator device (110). The cross-correlator device (110) is connected with a first cross-correlat...

  13. Swimming type inspection device and system thereof

    International Nuclear Information System (INIS)

    The present invention provides a swimming type inspection device which can be reduced in the size, easily accessible to each portion of a reactor, and increase the degree of freedom of swimming and visual range, and facilitate visual inspection. The swimming type inspection device comprises two photographing devices, a device which can obtain propelling force by rotation of impellers, two second propelling devices having impellers disposed in perpendicular to the rotating axis of the impellers of the first propelling device, a control device for controlling control signals of first and second propelling devices and driving devices therefor and control image signals of the photographing devices, and transmission section for wireless transmitting of the control signals and the image signals. (N.H.)

  14. Approaches to improve the Voc of CDTE devices: Device modeling and thinner devices, alternative back contacts

    Science.gov (United States)

    Walkons, Curtis J.

    An existing commercial process to develop thin film CdTe superstrate cells with a lifetime tau=1-3 ns results in Voc= 810-850 mV which is 350 mV lower than expected for CdTe with a bandgap EG = 1.5 eV. Voc is limited by 1.) SRH recombination in the space charge region; and 2.) the Cu2Te back contact to CdTe, which, assuming a 0.3 eV CdTe/Cu2Te barrier, exhibits a work function of phi Cu2Te= 5.5 eV compared to the CdTe valence band of Ev,CdTe=5.8 eV. Proposed solutions to develop CdTe devices with increased Voc are: 1.) reduce SRH recombination by thinning the CdTe layer to ≤ 1 mum; and 2.) develop an ohmic contact back contact using a material with phi BC≥5.8 eV. This is consistent with simulations using 1DSCAPS modeling of CdTe/CdS superstrate cells under AM 1.5 conditions. Two types of CdTe devices are presented. The first type of CdTe device utilizes a window/CdTe stack device with an initial 3-9 mum CdTe layer which is then chemically thinned resulting in regions of the CdTe film with thickness less than 1 mum. The CdTe surface was contacted with a liquid junction quinhydrone-Pt (QH-Pt) probe which enables rapid repeatable Voc measurements on CdTe before and after thinning. In four separate experiments, the window/CdTe stack devices with thinned CdTe exhibited a Voc increase of 30-170 mV, which if implemented using a solid state contact could cut the Voc deficit in half. The second type of CdTe device utilizes C61 PCBM as a back contact to the CdTe, selected since PCBM has a valence band maximum energy (VBM) of 5.8 eV. The PCBM films were grown by two different chemistries and the characterization of the film properties and device results are discussed. The device results show that PCBM exhibits a blocking contact with a 0.6 eV Schottky barrier and possible work function of phiPCBM = 5.2 eV.

  15. Diabetes Device Interoperability for Improved Diabetes Management

    OpenAIRE

    Silk, Alain D.

    2015-01-01

    Scientific and technological advancements have led to the increasing availability and use of sophisticated devices for diabetes management, with corresponding improvements in public health. These devices are often capable of sharing data with a few other specific devices but are generally not broadly interoperable; they cannot work together with a wide variety of other devices. As a result of limited interoperability, benefits of modern diabetes devices and potential for development of innova...

  16. Encapsulation methods for organic electrical devices

    Science.gov (United States)

    Blum, Yigal D.; Chu, William Siu-Keung; MacQueen, David Brent; Shi, Yijian

    2013-06-18

    The disclosure provides methods and materials suitable for use as encapsulation barriers in electronic devices. In one embodiment, for example, there is provided an electroluminescent device or other electronic device encapsulated by alternating layers of a silicon-containing bonding material and a ceramic material. The encapsulation methods provide, for example, electronic devices with increased stability and shelf-life. The invention is useful, for example, in the field of microelectronic devices.

  17. Integrated Device Control System using Google Maps

    Directory of Open Access Journals (Sweden)

    Takahiro KOITA

    2012-01-01

    Full Text Available This paper proposes an integrated device control system called Control Architecture for Networked Devices in Location Environments (CANDLE, which controls devices with Google Maps. Google Maps provides a global map interface and flexible APIs. The main motivation for this study is to provide a search and control system for physically distributed devices using Google Maps. To achieve this, the requirements of the system are (1 to coordinate device information with map information on Google Maps and (2 all distributed information has to be integrated on one interface. Device information is a set of information to control devices on an interface of Google Maps. CANDLE is an integrated device control system using Google Maps designed to meet these requirements. Using CANDLE, a user can control physically distributed devices through a web browser. In CANDLE, all device information is integrated into one map. CANDLE enables device control, searches, and display of information on distributed devices on an interface of Google Maps through a web browser. By using a web browser, a user can control devices from anywhere even if the devices are distributed globally. Thus, CANDLE is quite useful for distributed device control systems such as security, healthcare, and global monitoring systems.

  18. 76 FR 12973 - Neurological Devices Panel of the Medical Devices Advisory Committee; Amendment of Notice

    Science.gov (United States)

    2011-03-09

    ... HUMAN SERVICES Food and Drug Administration Neurological Devices Panel of the Medical Devices Advisory... Medical Devices Advisory Committee. This meeting was announced in the Federal Register of February 7, 2011... meeting of the Neurological Devices Panel of the Medical Devices Advisory Committee would be held on...

  19. Hardware device binding and mutual authentication

    Science.gov (United States)

    Hamlet, Jason R; Pierson, Lyndon G

    2014-03-04

    Detection and deterrence of device tampering and subversion by substitution may be achieved by including a cryptographic unit within a computing device for binding multiple hardware devices and mutually authenticating the devices. The cryptographic unit includes a physically unclonable function ("PUF") circuit disposed in or on the hardware device, which generates a binding PUF value. The cryptographic unit uses the binding PUF value during an enrollment phase and subsequent authentication phases. During a subsequent authentication phase, the cryptographic unit uses the binding PUF values of the multiple hardware devices to generate a challenge to send to the other device, and to verify a challenge received from the other device to mutually authenticate the hardware devices.

  20. Conduit purging device and method

    Science.gov (United States)

    Wilks, Michael T. (Inventor)

    2011-01-01

    A device for purging gas comprises a conduit assembly defining an interior volume. The conduit assembly comprises a first conduit portion having an open first end and an open second end and a second conduit portion having an open first end and a closed second end. The open second end of the first conduit portion is disposed proximate to the open first end of the second conduit portion to define a weld region. The device further comprises a supply element supplying a gas to the interior volume at a substantially constant rate and a vent element venting the gas from the interior volume at a rate that maintains the gas in the interior volume within a pressure range suitable to hold a weld bead in the weld region in equilibrium during formation of a weld to join the first conduit portion and the second conduit portion.

  1. Monitoring in IOT enabled devices

    Directory of Open Access Journals (Sweden)

    Udit Gupta

    2015-07-01

    Full Text Available As network size continues to grow exponentially, there has been a proportionate increase in the number of nodes in the corresponding network. With the advent of Internet of things (IOT, it is assumed that many more devices will be connected to the existing network infrastructure. As a result, monitoring is expected to get more complex for administrators as networks tend to become more heterogeneous. Moreover, the addressing for IOTs would be more complex given the scale at which devices will be added to the network and hence monitoring is bound to become an uphill task due to management of larger range of addresses. This paper will throw light on what kind of monitoring mechanisms can be deployed in internet of things (IOTs and their overall effectiveness.

  2. Safety of pulsed electric devices

    International Nuclear Information System (INIS)

    The strength–duration curve for tissue excitation can be modeled by a parallel resistor–capacitor circuit that has a time constant. We tested several short-duration electric generators: five electric fence energizers, the Taser X26 and a high-frequency generator to determine their current-versus-time waveforms. We estimated their safety characteristics using existing IEC and UL standards for electric fence energizers. The current standards are difficult to follow, with cumbersome calculations, and do not explicitly explain the physiological relevance of the calculated parameters. Hence we propose a new standard. The proposed new standard would consist of a physical RC circuit with a certain time constant. The investigator would discharge the device into a passive resistor–capacitor circuit and measure the resulting maximum voltage. If the maximum voltage does not exceed a limit, the device passes the test

  3. Insertion device calculations with mathematica

    Energy Technology Data Exchange (ETDEWEB)

    Carr, R. [Stanford Synchrotron Radiation Lab., CA (United States); Lidia, S. [Univ. of California, Davis, CA (United States)

    1995-02-01

    The design of accelerator insertion devices such as wigglers and undulators has usually been aided by numerical modeling on digital computers, using code in high level languages like Fortran. In the present era, there are higher level programming environments like IDL{reg_sign}, MatLab{reg_sign}, and Mathematica{reg_sign} in which these calculations may be performed by writing much less code, and in which standard mathematical techniques are very easily used. The authors present a suite of standard insertion device modeling routines in Mathematica to illustrate the new techniques. These routines include a simple way to generate magnetic fields using blocks of CSEM materials, trajectory solutions from the Lorentz force equations for given magnetic fields, Bessel function calculations of radiation for wigglers and undulators and general radiation calculations for undulators.

  4. Safety of pulsed electric devices.

    Science.gov (United States)

    Nimunkar, Amit J; Webster, John G

    2009-01-01

    The strength-duration curve for tissue excitation can be modeled by a parallel resistor-capacitor circuit that has a time constant. We tested several short-duration electric generators: five electric fence energizers, the Taser X26 and a high-frequency generator to determine their current-versus-time waveforms. We estimated their safety characteristics using existing IEC and UL standards for electric fence energizers. The current standards are difficult to follow, with cumbersome calculations, and do not explicitly explain the physiological relevance of the calculated parameters. Hence we propose a new standard. The proposed new standard would consist of a physical RC circuit with a certain time constant. The investigator would discharge the device into a passive resistor-capacitor circuit and measure the resulting maximum voltage. If the maximum voltage does not exceed a limit, the device passes the test.

  5. Infrared Devices And Techniques (Revision

    Directory of Open Access Journals (Sweden)

    Rogalski A.

    2014-12-01

    Full Text Available The main objective of this paper is to produce an applications-oriented review covering infrared techniques and devices. At the beginning infrared systems fundamentals are presented with emphasis on thermal emission, scene radiation and contrast, cooling techniques, and optics. Special attention is focused on night vision and thermal imaging concepts. Next section concentrates shortly on selected infrared systems and is arranged in order to increase complexity; from image intensifier systems, thermal imaging systems, to space-based systems. In this section are also described active and passive smart weapon seekers. Finally, other important infrared techniques and devices are shortly described, among them being: non-contact thermometers, radiometers, LIDAR, and infrared gas sensors.

  6. Energy Transfer in molecular devices

    CERN Document Server

    Caraglio, M

    2014-01-01

    Protein machines often exhibit long range interplay between different sites in order to achieve their biological tasks. We investigate and characterize the non--linear energy localization and the basic mechanisms of energy transfer in protein devices. By studying two different model protein machines, with different biological functions, we show that genuinely non--linear phenomena are responsible for energy transport between the different machine sites involved in the biological functions. The energy transfer turns out to be extremely efficient from an energetic point of view: by changing the energy initially provided to the model device, we identify a well defined range of energies where the time for the energy transport to occur is minimal and the amount of transferred energy is maximum. Furthermore, by introducing an implicit solvent, we show that the energy is localized on the internal residues of the protein structure, thus minimizing the dissipation.

  7. Reliability evaluation programmable logic devices

    International Nuclear Information System (INIS)

    Programmable Logic Devices (PLD) are widely used as basic building modules in high integrity systems, considering their robust features such as gate density, performance, speed etc. PLDs are used to implement digital design such as bus interface logic, control logic, sequencing logic, glue logic etc. Due to semiconductor evolution, new PLDs with state-of-the-art features are arriving to the market. Since these devices are reliable as per the manufacturer's specification, they were used in the design of safety systems. But due to their reduced market life, the availability of performance data is limited. So evaluating the PLD before deploying in a safety system is very important. This paper presents a survey on the use of PLDs in the nuclear domain and the steps involved in the evaluation of PLD using Quantitative Accelerated Life Testing. (author)

  8. Nanowire structures and electrical devices

    Science.gov (United States)

    Bezryadin, Alexey; Remeika, Mikas

    2010-07-06

    The present invention provides structures and devices comprising conductive segments and conductance constricting segments of a nanowire, such as metallic, superconducting or semiconducting nanowire. The present invention provides structures and devices comprising conductive nanowire segments and conductance constricting nanowire segments having accurately selected phases including crystalline and amorphous states, compositions, morphologies and physical dimensions, including selected cross sectional dimensions, shapes and lengths along the length of a nanowire. Further, the present invention provides methods of processing nanowires capable of patterning a nanowire to form a plurality of conductance constricting segments having selected positions along the length of a nanowire, including conductance constricting segments having reduced cross sectional dimensions and conductance constricting segments comprising one or more insulating materials such as metal oxides.

  9. Neutron-absorber release device

    Science.gov (United States)

    VAN Erp, Jan B.; Kimont, Edward L.

    1976-01-01

    A resettable device is provided for supporting an object, sensing when an environment reaches a critical temperature and releasing the object when the critical temperature is reached. It includes a flexible container having a material inside with a melting point at the critical temperature. The object's weight is supported by the solid material which gives rigidity to the container until the critical temperature is reached at which point the material in the container melts. The flexible container with the now fluid material inside has insufficient strength to support the object which is thereby released. Biasing means forces the container back to its original shape so that when the temperature falls below the melting temperature the material again solidifies, and the object may again be supported by the device.

  10. User Experience of Mobile Devices

    DEFF Research Database (Denmark)

    Raptis, Dimitrios

    This thesis focuses on mobile devices and it specifically investigates the effect of their physical form on two perceived user experience qualities, usability and coolness. With the term mobile devices, I refer to interactive products that users interact with while being on the move....... The thesis consists of four research papers and a statement. The four individual papers provide answers to the two research questions, while the statement acts as a bridge that brings the papers together into a coherent whole. The statement initially discusses what user experience and physical form are...... studies focus on generating enough data to map out a relatively unknown phenomenon, while validation studies confirm cause-effect relationships that have been identified from previous research. The statement continues with a discussion on the implications of my findings to the broader user experience...

  11. Dielectrokinetic chromatography and devices thereof

    Science.gov (United States)

    Chirica, Gabriela S; Fiechtner, Gregory J; Singh, Anup K

    2014-04-22

    Disclosed herein are methods and devices for dielectrokinetic chromatography. As disclosed, the devices comprise microchannels having at least one perturber which produces a non-uniformity in a field spanning the width of the microchannel. The interaction of the field non-uniformity with a perturber produces a secondary flow which competes with a primary flow. By decreasing the size of the perturber the secondary flow becomes significant for particles/analytes in the nanometer-size range. Depending on the nature of a particle/analyte present in the fluid and its interaction with the primary flow and the secondary flow, the analyte may be retained or redirected. The composition of the primary flow can be varied to affect the magnitude of primary and/or secondary flows on the particles/analytes and thereby separate and concentrate it from other particles/analytes.

  12. Synthetic circuits, devices and modules

    OpenAIRE

    Zhang, Hong; Jiang, Taijiao

    2010-01-01

    The aim of synthetic biology is to design artificial biological systems for novel applications. From an engineering perspective, construction of biological systems of defined functionality in a hierarchical way is fundamental to this emerging field. Here, we highlight some current advances on design of several basic building blocks in synthetic biology including the artificial gene control elements, synthetic circuits and their assemblies into devices and modules. Such engineered basic buildi...

  13. Capacitor ageing in electronic devices

    OpenAIRE

    Richard B. N. Vital; Tatiane M. Vital

    2015-01-01

    The moment when an electronic component doesn’t work like requirements, previously established is a task that need to be considered since began of a system design. However, the use of different technologies, operating under several environmental conditions, makes a component choice a complex step in system design. This paper analyzes the effects that ageing phenomenon of capacitors may introduce in electronic devices operation. For this reason, reliability concepts, processes and ...

  14. Fusion Engineering Device design description

    Energy Technology Data Exchange (ETDEWEB)

    Flanagan, C.A.; Steiner, D.; Smith, G.E.

    1981-12-01

    The US Magnetic Fusion Engineering Act of 1980 calls for the operation of a Fusion Engineering Device (FED) by 1990. It is the intent of the Act that the FED, in combination with other testing facilities, will establish the engineering feasibility of magnetic fusion energy. During 1981, the Fusion Engineering Design Center (FEDC), under the guidance of a Technical Management Board (TMB), developed a baseline design for the FED. This design is summarized herein.

  15. Fusion engineering device design description

    International Nuclear Information System (INIS)

    The US Magnetic Fusion Engineering Act of 1980 calls for the operation of a Fusion Engineering Device (FED) by 1990. It is the intent of the Act that the FED, in combination with other testing facilities, will establish the engineering feasibility of magnetic fusion energy. During 1981, the Fusion Engineering Design Center (FEDC), under the guidance of a Technical Management Board (TMB), developed a baseline design for the FED. This design is summarized herein

  16. Infrared Devices And Techniques (Revision)

    OpenAIRE

    Rogalski A.; Chrzanowski K.

    2014-01-01

    The main objective of this paper is to produce an applications-oriented review covering infrared techniques and devices. At the beginning infrared systems fundamentals are presented with emphasis on thermal emission, scene radiation and contrast, cooling techniques, and optics. Special attention is focused on night vision and thermal imaging concepts. Next section concentrates shortly on selected infrared systems and is arranged in order to increase complexity; from image intensifier systems,...

  17. Infrared detector device inspection system

    Energy Technology Data Exchange (ETDEWEB)

    Soehnel, Grant; Bender, Daniel A.

    2016-08-09

    Methods and apparatuses for identifying carrier lifetimes are disclosed herein. In a general embodiment, a beam of light is sent to a group of locations on a material for an optical device. Photons emitted from the material are detected at each of the group of locations. A carrier lifetime is identified for each of the group of locations based on the photons detected from each of the group of locations.

  18. Nanoscale Electrothermal Energy Conversion Devices

    OpenAIRE

    Bahk, Je-Hyeong; Ezzahri, Younes; Yazawa, Kazuaki; Vermeersch, Bjorn; Pernot, Gilles; Shakouri, Ali

    2012-01-01

    Energy consumption in our society is increasing rapidly. A significant fraction of the energy is lost in the form of heat. In this talk we introduce thermoelectric devices that allow direct conversion of heat into electricity. Some new physical concepts and nanostructures make it possible to modify the trade-offs between the bulk electrothermal material properties through the changes in the density of states, scattering rates, and interface effects on the electron and phonon transport. The po...

  19. Fusion Engineering Device design description

    International Nuclear Information System (INIS)

    The US Magnetic Fusion Engineering Act of 1980 calls for the operation of a Fusion Engineering Device (FED) by 1990. It is the intent of the Act that the FED, in combination with other testing facilities, will establish the engineering feasibility of magnetic fusion energy. During 1981, the Fusion Engineering Design Center (FEDC), under the guidance of a Technical Management Board (TMB), developed a baseline design for the FED. This design is summarized herein

  20. Wiki keys on mobile devices

    OpenAIRE

    Weber, Gisela; Hagedorn, Gregor

    2010-01-01

    The development of increasingly powerful mobile devices like PDAs (Personal Digital Assistants) and Smartphones, with larger displays and greater resolution makes them increasingly suitable for identification tools available directly “in the field”. One of several approaches towards this aim in the KeyToNature project is based on wiki-stored documents. Important features of wiki-based keys, such as hidden text and media information as well as links to glossary entries are su...

  1. Thermal transport in mesoscopic devices

    OpenAIRE

    Ruokola, Tomi

    2012-01-01

    New mechanisms for controlling heat flow and for converting heat to work in small-scale solid-state systems are highly desirable, particularly when considering the rapid miniaturization and ever-increasing power densities of electronic devices. Mesoscopic structures, being much larger than individual atoms but still small enough to exhibit some quantum-mechanical features, offer a versatile platform for studying thermal phenomena at reduced length scales. We perform a theoretical study of ...

  2. Magnetoelectric laminated composites and devices

    OpenAIRE

    Zhai, Junyi

    2009-01-01

    Since the turn of the millennium, giant magnetoelectric (ME) effects have been found in laminated composites of piezoelectric and magnetostrictive layers. Compared to ME single phase and two phase particulate composites, laminated composites have much higher ME coefficients and are also readily fabricated. In this thesis, I have investigated ME effect in laminated composites including materials, structures, fundamental properties and devices. Giant permeability Metglas was incorporated in...

  3. Portable vacuum object handling device

    Science.gov (United States)

    Anderson, G.H.

    1983-08-09

    The disclosure relates to a portable device adapted to handle objects which are not to be touched by hand. A piston and bore wall form a vacuum chamber communicating with an adaptor sealably engageable with an object to be lifted. The piston is manually moved and set to establish vacuum. A valve is manually actuatable to apply the vacuum to lift the object. 1 fig.

  4. Game Design for Mobile Devices

    OpenAIRE

    ODSTAM, MÅNS; STJ ERNDAL, A N D R E A S

    2013-01-01

    In the last few years there has been an incredible rise in the amount of game applications available for the latest generation of mobile platforms. An increasing amount of developers and companies are starting to invest more heavily in producing for this growing market. This report investigates some of the challenges faced when developing these games, with the focus on the genre turn based strategy games. The main areas that are explored are the time of a session with the device, the touchscr...

  5. Evaluating Readability on Mobile Devices

    OpenAIRE

    Öquist, Gustav

    2006-01-01

    The thesis presents findings from five readability studies performed on mobile devices. The dynamic Rapid Serial Visual Presentation (RSVP) format has been enhanced with regard to linguistic adaptation and segmentation as well as eye movement modeling. The novel formats have been evaluated against other common presentation formats including Paging, Scrolling, and Leading in latin-square balanced repeated-measurement studies with 12-16 subjects. Apart from monitoring Reading speed, Comprehensi...

  6. Fusion engineering device design description

    Energy Technology Data Exchange (ETDEWEB)

    Flanagan, C.A.; Steiner, D.; Smith, G.E.

    1981-12-01

    The US Magnetic Fusion Engineering Act of 1980 calls for the operation of a Fusion Engineering Device (FED) by 1990. It is the intent of the Act that the FED, in combination with other testing facilities, will establish the engineering feasibility of magnetic fusion energy. During 1981, the Fusion Engineering Design Center (FEDC), under the guidance of a Technical Management Board (TMB), developed a baseline design for the FED. This design is summarized herein.

  7. Numerical Modeling of Nanoelectronic Devices

    Science.gov (United States)

    Klimeck, Gerhard; Oyafuso, Fabiano; Bowen, R. Chris; Boykin, Timothy

    2003-01-01

    Nanoelectronic Modeling 3-D (NEMO 3-D) is a computer program for numerical modeling of the electronic structure properties of a semiconductor device that is embodied in a crystal containing as many as 16 million atoms in an arbitrary configuration and that has overall dimensions of the order of tens of nanometers. The underlying mathematical model represents the quantummechanical behavior of the device resolved to the atomistic level of granularity. The system of electrons in the device is represented by a sparse Hamiltonian matrix that contains hundreds of millions of terms. NEMO 3-D solves the matrix equation on a Beowulf-class cluster computer, by use of a parallel-processing matrix vector multiplication algorithm coupled to a Lanczos and/or Rayleigh-Ritz algorithm that solves for eigenvalues. In a recent update of NEMO 3-D, a new strain treatment, parameterized for bulk material properties of GaAs and InAs, was developed for two tight-binding submodels. The utility of the NEMO 3-D was demonstrated in an atomistic analysis of the effects of disorder in alloys and, in particular, in bulk In(x)Ga(l-x)As and in In0.6Ga0.4As quantum dots.

  8. Metamaterial mirrors in optoelectronic devices

    KAUST Repository

    Esfandyarpour, Majid

    2014-06-22

    The phase reversal that occurs when light is reflected from a metallic mirror produces a standing wave with reduced intensity near the reflective surface. This effect is highly undesirable in optoelectronic devices that use metal films as both electrical contacts and optical mirrors, because it dictates a minimum spacing between the metal and the underlying active semiconductor layers, therefore posing a fundamental limit to the overall thickness of the device. Here, we show that this challenge can be circumvented by using a metamaterial mirror whose reflection phase is tunable from that of a perfect electric mirror († = €) to that of a perfect magnetic mirror († = 0). This tunability in reflection phase can also be exploited to optimize the standing wave profile in planar devices to maximize light-matter interaction. Specifically, we show that light absorption and photocurrent generation in a sub-100 nm active semiconductor layer of a model solar cell can be enhanced by ∼20% over a broad spectral band. © 2014 Macmillan Publishers Limited.

  9. From MEMRISTOR to MEMImpedance device

    Science.gov (United States)

    Wakrim, T.; Vallée, C.; Gonon, P.; Mannequin, C.; Sylvestre, A.

    2016-02-01

    The behavior of the capacitance switching of HfO2 Resistive non-volatile Memories is investigated in view of realizing a MEMImpedance (MEM-Z) device. In such a Metal Insulator Metal structure, the impedance value can be tuned by the adjustment of both resistance and capacitance values. We observe a strong variation of capacitance from positive to negative values in a single layer Metal Insulator Metal device made of HfO2 deposited by Atomic Layer Deposition, but unfortunately no memory effect is observed. However, in the case of a two layer structure, a device has been obtained with a memory effect where both resistance and capacitance values can be tuned simultaneously, with a variation of capacitance down to negative values to get an inductive behavior. Negative capacitance values are observed for voltage values near SET voltage. A schematic model based on shaped oxygen vacancy density is proposed to account for this capacitance variation. The oxygen vacancies can be either isolated or connected in the bulk of the oxide.

  10. Microencapsulation and Electrostatic Processing Device

    Science.gov (United States)

    Morrison, Dennis R. (Inventor); Mosier, Benjamin (Inventor); Cassanto, John M. (Inventor)

    2001-01-01

    A microencapsulation and electrostatic processing (MEP) device is provided for forming microcapsules. In one embodiment, the device comprises a chamber having a filter which separates a first region in the chamber from a second region in the chamber. An aqueous solution is introduced into the first region through an inlet port, and a hydrocarbon/ polymer solution is introduced into the second region through another inlet port. The filter acts to stabilize the interface and suppress mixing between the two immiscible solutions as they are being introduced into their respective regions. After the solutions have been introduced and have become quiescent, the interface is gently separated from the filter. At this point, spontaneous formation of microcapsules at the interface may begin to occur, or some fluid motion may be provided to induce microcapsule formation. In any case, the fluid shear force at the interface is limited to less than 100 dynes/sq cm. This low-shear approach to microcapsule formation yields microcapsules with good sphericity and desirable size distribution. The MEP device is also capable of downstream processing of microcapsules, including rinsing, re-suspension in tertiary fluids, electrostatic deposition of ancillary coatings, and free-fluid electrophoretic separation of charged microcapsules.

  11. Mobile biometric device (MBD) technology :

    Energy Technology Data Exchange (ETDEWEB)

    Aldridge, Chris D.

    2013-06-01

    Mobile biometric devices (MBDs) capable of both enrolling individuals in databases and performing identification checks of subjects in the field are seen as an important capability for military, law enforcement, and homeland security operations. The technology is advancing rapidly. The Department of Homeland Security Science and Technology Directorate through an Interagency Agreement with Sandia sponsored a series of pilot projects to obtain information for the first responder law enforcement community on further identification of requirements for mobile biometric device technology. Working with 62 different jurisdictions, including components of the Department of Homeland Security, Sandia delivered a series of reports on user operation of state-of-the-art mobile biometric devices. These reports included feedback information on MBD usage in both operational and exercise scenarios. The findings and conclusions of the project address both the limitations and possibilities of MBD technology to improve operations. Evidence of these possibilities can be found in the adoption of this technology by many agencies today and the cooperation of several law enforcement agencies in both participating in the pilot efforts and sharing of information about their own experiences in efforts undertaken separately.

  12. Virtual cathode microwave devices -- Basics

    Energy Technology Data Exchange (ETDEWEB)

    Thode, L.E.; Snell, C.M.

    1991-01-01

    Unlike a conventional microwave tube, a virtual-cathode device operates above the space-charge limit where the depth of the space-charge potential can cause electron reflection. The region associated with this electron reflection is referred to as a virtual cathode. Microwaves can be generated through oscillations in the position of the virtual cathode and through the bunching of electrons trapped in a potential well between the real and virtual cathodes. These two mechanisms are competitive. There are three basic classes of virtual cathode devices: (1) reflex triode; (2) reditron and side-shoot vircator; and (3) reflex diode or vircator. The reflex diode is the highest power virtual-cathode device. For the reflex diode the energy exchange between the beam and electromagnetic wave occurs in both the axial and radial directions. In some designs the oscillating-virtual-cathode frequency exceeds the reflexing-electron frequency exceeds the oscillating-virtual-cathode frequency. For the flex diode a periodic disruption in magnetic insulation can modulate the high- frequency microwave power. Overall, particle-in-cell simulation predictions and axial reflex diode experiments are in good agreement. Although frequency stability and phase locking of the reflex diode have been demonstrated, little progress has been made in efficiency enhancement. 58 refs., 11 figs.

  13. Virtual cathode microwave devices: Basics

    Science.gov (United States)

    Thode, L. E.; Snell, C. M.

    Unlike a conventional microwave tube, a virtual-cathode device operates above the space-charge limit where the depth of the space-charge potential can cause electron reflection. The region associated with this electron reflection is referred to as a virtual cathode. Microwaves can be generated through oscillations in the position of the virtual cathode and through the bunching of electrons trapped in a potential well between the real and virtual cathodes. These two mechanisms are competitive. There are three basic classes of virtual cathode devices: (1) reflex triode; (2) reditron and side-shoot vircator; and (3) reflex diode or vircator. The reflex diode is the highest power virtual-cathode device. For the reflex diode the energy exchange between the beam and electromagnetic wave occurs in both the axial and radial directions. In some designs the oscillating virtual-cathode frequency exceeds the reflexing-electron frequency while in other designs the reflexing-electron frequency exceeds the oscillating virtual-cathode frequency. For the flex diode, a periodic disruption in magnetic insulation can modulate the high-frequency microwave power. Overall, particle-in-cell simulation predictions and axial reflex diode experiments are in good agreement. Although frequency stability and phase locking of the reflex diode have been demonstrated, little progress has been made in efficiency enhancement.

  14. Cotton-based diagnostic devices.

    Science.gov (United States)

    Lin, Shang-Chi; Hsu, Min-Yen; Kuan, Chen-Meng; Wang, Hsi-Kai; Chang, Chia-Ling; Tseng, Fan-Gang; Cheng, Chao-Min

    2014-01-01

    A good diagnostic procedure avoids wasting medical resources, is easy to use, resists contamination, and provides accurate information quickly to allow for rapid follow-up therapies. We developed a novel diagnostic procedure using a "cotton-based diagnostic device" capable of real-time detection, i.e., in vitro diagnostics (IVD), which avoids reagent contamination problems common to existing biomedical devices and achieves the abovementioned goals of economy, efficiency, ease of use, and speed. Our research reinforces the advantages of an easy-to-use, highly accurate diagnostic device created from an inexpensive and readily available U.S. FDA-approved material (i.e., cotton as flow channel and chromatography paper as reaction zone) that adopts a standard calibration curve method in a buffer system (i.e., nitrite, BSA, urobilinogen and uric acid assays) to accurately obtain semi-quantitative information and limit the cross-contamination common to multiple-use tools. Our system, which specifically targets urinalysis diagnostics and employs a multiple biomarker approach, requires no electricity, no professional training, and is exceptionally portable for use in remote or home settings. This could be particularly useful in less industrialized areas. PMID:25393975

  15. From MEMRISTOR to MEMImpedance device

    Energy Technology Data Exchange (ETDEWEB)

    Wakrim, T. [Univ. Grenoble Alpes, LTM (CEA-LETI/Minatec), 38000 Grenoble (France); Univ. Grenoble Alpes, G2Elab, F-38000 Grenoble (France); Vallée, C., E-mail: christophe.vallee@cea.fr; Gonon, P.; Mannequin, C. [Univ. Grenoble Alpes, LTM (CEA-LETI/Minatec), 38000 Grenoble (France); Sylvestre, A. [Univ. Grenoble Alpes, G2Elab, F-38000 Grenoble (France)

    2016-02-01

    The behavior of the capacitance switching of HfO{sub 2} Resistive non-volatile Memories is investigated in view of realizing a MEMImpedance (MEM-Z) device. In such a Metal Insulator Metal structure, the impedance value can be tuned by the adjustment of both resistance and capacitance values. We observe a strong variation of capacitance from positive to negative values in a single layer Metal Insulator Metal device made of HfO{sub 2} deposited by Atomic Layer Deposition, but unfortunately no memory effect is observed. However, in the case of a two layer structure, a device has been obtained with a memory effect where both resistance and capacitance values can be tuned simultaneously, with a variation of capacitance down to negative values to get an inductive behavior. Negative capacitance values are observed for voltage values near SET voltage. A schematic model based on shaped oxygen vacancy density is proposed to account for this capacitance variation. The oxygen vacancies can be either isolated or connected in the bulk of the oxide.

  16. Assembly of high voltage devices

    Energy Technology Data Exchange (ETDEWEB)

    Cameroni, R.; Granata, C.; Calamari, L.; Gatti, P. [ABB PTPH U.O. ADDA, Lodi (Italy)

    2008-07-01

    Electric utilities are required to provide high quality power delivery. ABB has developed a new type of switching device that combines a circuit breaker and one or more disconnectors and their control gears. These high voltage switchgear components are based either on air-insulated technology (AIS), or on gas-insulated technology (GIS) or a combination of both. The use of hybrid switchgear has enabled the development of simplified substations with many advantages, such as less space required due to GIS technology; higher flexibility of layout versus AIS; bus reconfiguration for increased system reliability and reduced outages; easier engineering; reduced maintenance and costs; easier integration of secondary systems; fast installation; and easy replacement in case of failure. The life cycle cost of the ABB hybrid modules has been evaluated on the basis of different network configuration scenarios, including indoor and outdoor installations. The International Electrotechnical Commission is preparing a new standard IEC 62271-205 to classify the combination of switching devices as assemblies of high voltage devices. 2 refs., 12 figs.

  17. Learning from adverse incidents involving medical devices.

    Science.gov (United States)

    Amoore, John; Ingram, Paula

    While an adverse event involving a medical device is often ascribed to either user error or device failure, the causes are typically multifactorial. A number of incidents involving medical devices are explored using this approach to investigate the various causes of the incident and the protective barriers that minimised or prevented adverse consequences. User factors, including mistakes, omissions and lack of training, conspired with background factors--device controls and device design, storage conditions, hidden device damage and physical layout of equipment when in use--to cause the adverse events. Protective barriers that prevented or minimised the consequences included staff vigilance, operating procedures and alarms. PMID:12715578

  18. Optical Structural Health Monitoring Device

    Science.gov (United States)

    Buckner, Benjamin D.; Markov, Vladimir; Earthman, James C.

    2010-01-01

    This non-destructive, optical fatigue detection and monitoring system relies on a small and unobtrusive light-scattering sensor that is installed on a component at the beginning of its life in order to periodically scan the component in situ. The method involves using a laser beam to scan the surface of the monitored component. The device scans a laser spot over a metal surface to which it is attached. As the laser beam scans the surface, disruptions in the surface cause increases in scattered light intensity. As the disruptions in the surface grow, they will cause the light to scatter more. Over time, the scattering intensities over the scanned line can be compared to detect changes in the metal surface to find cracks, crack precursors, or corrosion. This periodic monitoring of the surface can be used to indicate the degree of fatigue damage on a component and allow one to predict the remaining life and/or incipient mechanical failure of the monitored component. This wireless, compact device can operate for long periods under its own battery power and could one day use harvested power. The prototype device uses the popular open-source TinyOS operating system on an off-the-shelf Mica2 sensor mote, which allows wireless command and control through dynamically reconfigurable multi-node sensor networks. The small size and long life of this device could make it possible for the nodes to be installed and left in place over the course of years, and with wireless communication, data can be extracted from the nodes by operators without physical access to the devices. While a prototype has been demonstrated at the time of this reporting, further work is required in the system s development to take this technology into the field, especially to improve its power management and ruggedness. It should be possible to reduce the size and sensitivity as well. Establishment of better prognostic methods based on these data is also needed. The increase of surface roughness with

  19. Fast response liquid crystal devices

    Science.gov (United States)

    Wu, Yung-Hsun

    Liquid crystal (LC) has been widely used for displays, spatial light modulators, variable optical attenuators (VOAs) and other tunable photonic devices. The response time of these devices is mainly determined by the employed liquid crystal material. The response time of a LC device depends on the visco-elastic coefficient (gamma1/K11), LC cell gap (d), and applied voltage. Hence, low visco-elastic coefficient LC materials and thinner cell gap are favorable for reducing the response time. However, low visco-elastic coefficient LCs are usually associated with a low birefringence because of shorter molecular conjugation. For display applications, such as LCD TVs, low birefringence (Deltanthick cell gap which, in turn, increases the response time. How to obtain fast response for the LC devices is a fundamentally important and technically challenging task. In this dissertation, we investigate several methods to improve liquid crystal response time, for examples, using dual-frequency liquid crystals, polymer stabilized liquid crystals, and sheared polymer network liquid crystals. We discover a new class of material, denoted as sheared polymer network liquid crystal (SPNLC) which exhibits a submillisecond response time. Moreover, this response time is insensitive to the LC cell gap. This is the first LC device exhibiting such an interesting property. Chapters 1 and 2 describe the motivation and background of this dissertation. From chapter 3 to chapter 6, dual-frequency liquid crystals and polymer network methods are demonstrated as examples for the variable optical attenuators. Variable optical attenuator (VOA) is a key component in optical communications. Especially, the sheared PNLC VOA shows the best result; its dynamic range reaches 43 dB while the response time is in the submillisecond range at 1550 nm wavelength, which is 50 times faster than the commercial LC-based VOA. In Chapter 7, we report a new device called axially-symmetric sheared polymer network liquid

  20. Wireless device connection problems and design solutions

    Science.gov (United States)

    Song, Ji-Won; Norman, Donald; Nam, Tek-Jin; Qin, Shengfeng

    2016-09-01

    Users, especially the non-expert users, commonly experience problems when connecting multiple devices with interoperability. While studies on multiple device connections are mostly concentrated on spontaneous device association techniques with a focus on security aspects, the research on user interaction for device connection is still limited. More research into understanding people is needed for designers to devise usable techniques. This research applies the Research-through-Design method and studies the non-expert users' interactions in establishing wireless connections between devices. The "Learning from Examples" concept is adopted to develop a study focus line by learning from the expert users' interaction with devices. This focus line is then used for guiding researchers to explore the non-expert users' difficulties at each stage of the focus line. Finally, the Research-through-Design approach is used to understand the users' difficulties, gain insights to design problems and suggest usable solutions. When connecting a device, the user is required to manage not only the device's functionality but also the interaction between devices. Based on learning from failures, an important insight is found that the existing design approach to improve single-device interaction issues, such as improvements to graphical user interfaces or computer guidance, cannot help users to handle problems between multiple devices. This study finally proposes a desirable user-device interaction in which images of two devices function together with a system image to provide the user with feedback on the status of the connection, which allows them to infer any required actions.