Science.gov

Sample records for deflective separation cds

  1. Isotope separation by selective charge conversion and field deflection

    DOEpatents

    Hickman, Robert G.

    1978-01-01

    A deuterium-tritium separation system wherein a source beam comprised of positively ionized deuterium (D.sup.+) and tritium (T.sup.+) is converted at different charge-exchange cell sections of the system to negatively ionized deuterium (D.sup.-) and tritium (T.sup.-). First, energy is added to the beam to accelerate the D.sup.+ ions to the velocity that is optimum for conversion of the D.sup.+ ions to D.sup.- ions in a charge-exchange cell. The T.sup.+ ions are accelerated at the same time, but not to the optimum velocity since they are heavier than the D.sup.+ ions. The T.sup.+ ions are, therefore, not converted to T.sup.- ions when the D.sup.+ ions are converted to D.sup.- ions. This enables effective separation of the beam by deflection of the isotopes with an electrostatic field, the D.sup.- ions being deflected in one direction and the T.sup.+ ions being deflected in the opposite direction. Next, more energy is added to the deflected beam of T.sup.+ ions to bring the T.sup.+ ions to the optimum velocity for their conversion to T.sup.- ions. In a particular use of the invention, the beams of D.sup.- and T.sup.- ions are separately further accelerated and then converted to energetic neutral particles for injection as fuel into a thermonuclear reactor. The reactor exhaust of D.sup.+ and T.sup.+ and the D.sup.+ and T.sup.+ that was not converted in the respective sections is combined with the source beam and recycled through the system to increase the efficiency of the system.

  2. CDS

    NASA Astrophysics Data System (ADS)

    Allen, Mark

    2015-12-01

    The Centre de Donnees de Strasbourg (CDS) is a reference data centre for Astronomy. The CDS services; SIMBAD, Vizier, Aladin and X-Match, provide added value to scientific content in order to support the astronomy research community. Data and information are curated from refereed journals, major surveys, observatories and missions with a strong emphasis on maintaining a high level of quality. The current status and plans of the CDS will be presented, highlighting how the recent innovations of the HiPS (Hierarchical Progressive surveys) and MOC (Multi-Order Coverage map) systems enable the visualisation of hundreds of surveys and data sets, and brings new levels of interoperability between catalogues, surveys images and data cubes.

  3. Clusius-Dickel Separations (CDS): A new look at an old technique

    NASA Technical Reports Server (NTRS)

    Grodzka, P. G.

    1975-01-01

    The history, applications, and theoretical basis of the CDS technique are reviewed. The advantage to be realized by conduction of CDSs in low-g, space environments are deduced. The results are reported of investigations aimed at further improving CDS efficiencies by altering convective flow patterns. The question of whether multicellular flow or turbulence can introduce a new separation mechanism which would boost separation efficiencies at least an order of magnitude is considered. Results are presented and discussed.

  4. Theoretical study on isotope separation of an ytterbium atomic beam by laser deflection

    NASA Astrophysics Data System (ADS)

    Zhou, Min; Xu, Xin-Ye

    2014-01-01

    Isotope separation by laser deflecting an atomic beam is analyzed theoretically. Interacting with a tilted one-dimensional optical molasses, an ytterbium atomic beam is split into multi-beams with different isotopes like 172Yb,173Yb, and 174Yb. By using the numerical calculation, the dependences of the splitting angle on the molasses laser intensity and detuning are studied, and the optimal parameters for the isotope separation are also investigated. Furthermore, the isotope separation efficiency and purity are estimated. Finally a new scheme for the efficient isotope separation is proposed. These findings will give a guideline for simply obtaining pure isotopes of various elements.

  5. Experimental and theoretical analysis of DEP-based particle deflection for the separation of protein-bound particles

    NASA Astrophysics Data System (ADS)

    Kim, Min-Soo; Kim, Jong-Ho; Lee, Yoon-Sik; Lim, Geon-Gyu; Lee, Hyang-Beom; Park, Jae-Hyoung; Kim, Yong-Kweon

    2009-01-01

    We present an experimental and theoretical analysis of dielectrophoretic (DEP) particle deflection in a microfluidic channel for the separation of protein-bound particles. A 2D electrode array with widely spaced bars is designed to deflect a particle at the exit of the fluidic channel by negative DEP force. When particles pass through the channel, the particle streams are deflected differently depending on the DEP characteristics of the particles. In this paper, we propose methodologies to characterize the DEP force with the deflection distance using comparative analyses of a simulation and an experiment. The deflection distances of the particles are measured as a function of the ac voltage applied and compared with full 3D simulations. The Clausius-Mossotti (CM) factor of a protein-bound particle is analyzed, based on frequency-dependent deflection distance data measured experimentally, and protein-bound particles are separated from a mixture with nonbound particles in a real application. Two particle groups, 2.3 µm and 6.4 µm polystyrene particles, were used for the simulation and experimental study, and the 6.4 µm diameter particles were selected as an adequate protein-binding substrate for the application of biomolecular detection. Bovine serum albumin (BSA) was used as a test target protein. The particle's BSA binding is identified by the change in the particle's deflection distance. In particular, we used 1 wt% BSA as a target protein sample to investigate the deflection of 6.4 µm diameter particles as a function of protein concentration. The frequency-dependent CM factor curves for BSA-bound and nonbound particles are also calculated theoretically. Therefore, this paper shows a model analytic study on the biomolecular detection performance of a fabricated DEP-deflection microsystem. In addition, we present further significant analyses such as calculation of the electrical surface conductance of BSA around a particle, and we trace simulation errors. The

  6. Deflecting Shearpin

    NASA Technical Reports Server (NTRS)

    Gregory, Peyton B.

    1993-01-01

    Spring loading helps prevent permanent deformation of adjacent bearing surfaces. Shearpin deflects as load compresses inner spring. Maximum deflection determined by gap between halves of capture ring. Beyond deflection, pin acts as standard shearpin.

  7. Large-angular separation of particles induced by cascaded deflection angles in optical sorting

    PubMed Central

    Yuan, X.-C.; Zhu, S. W.; Bu, J.; Sun, Y. Y.; Lin, J.; Gao, Bruce Z.

    2013-01-01

    A composite microlens array (MLA) with two cascaded guiding axes has been fabricated to achieve a large lateral separation of an object with different refractive indices or sizes. The MLA projects a composite pattern formed by its focal spots into a microchamber for optical sorting in a microscopic system. This approach enables passive, high power, efficient, and continuous microfluidic sorting without requiring complicated optical assembly. Separation of particles with different refractive indices to a lateral angle of 40° is experimentally demonstrated with moderate laser power. PMID:23997243

  8. CDS - Database Administrator's Guide

    NASA Astrophysics Data System (ADS)

    Day, J. P.

    This guide aims to instruct the CDS database administrator in: o The CDS file system. o The CDS index files. o The procedure for assimilating a new CDS tape into the database. It is assumed that the administrator has read SUN/79.

  9. Functionalized CdS nanospheres and nanorods

    NASA Astrophysics Data System (ADS)

    Lee, Hyeokjin; Yang, Heesun; Holloway, Paul H.

    2009-12-01

    Functionalized nanoparticles are discussed. Surfaces of CdS:Mn/ZnS core/shell nanospheres (Qdots) were converted from hydrophobic to hydrophilic by growth of a SiO 2 shell. The colloidal dispersion was stabilize by adding a surfactant with a negative surface charge, and a cell-penetrating-peptide, TAT, was attached through a primary amine group. The TAT functionalized Qdots were shown to pass the blood-brain-barrier and luminescence in the infused half of the brain. In addition, nanorods of S 2- rich CdS were synthesized by reaction of excess S with Cd precursors in the presence of ethylene diamine. The photoluminescence (PL) peak from the S 2- rich CdS nanorods was broad with a maximum at ∼710 nm, which was 40 nm longer in wavelength than the PL peak from Cd 2+ rich CdS (∼670 nm) nanorods. The influence of surface electron or hole trap states on the luminescent pathway of CdS nanorods were used to explain these shifts in wavelength. Nanocrystals of Au with ∼2 nm diameters were grown on S 2- rich surfaces of CdS nanorods. Significant quenching of photoluminescence was observed from Au nanocrystals on CdS nanorods due to interfacial charge separation. Charge separation by Au nanocrystals on CdS resulted in enhanced UV photocatalytic degradation of Procion red mix-5B (PRB) dye in aqueous solution.

  10. Microwave Deflection Sensor

    NASA Technical Reports Server (NTRS)

    Shores, Paul; Kobayashi, Herb; Ngo, Phong; Lichtenberg, C. L.

    1988-01-01

    Doppler-radar instrument measures small deflections or vibrations of reflecting surface. Acting as interferometric micrometer, instrument includes combination of analog and digital circuits measuring change in phase of radar return due to movement of reflecting surface along signal-propagation path. Includes homodyne Doppler-radar transceiver and digital signal-processing circuitry to measure change in phase shift as target deflects.

  11. Dynamic pavement deflection

    NASA Astrophysics Data System (ADS)

    Rand, D. W.; Jacobs, K. M.

    1981-06-01

    Dynamic pavement deflection measurements for bituminous concrete pavements of two and three-quarter, five and seven-eights, and seven and one-half inches in thickness under moving axle loads of 15,000, 18,000, and 22,000 pounds were obtained at speeds of 10, 25 and 45 miles per hour. The results were analyzed and compared to Benkelman beam measurements. The data indicate that slow moving loads have greater adverse effect (larger deflections) on the pavement than the high speed loads. The results also show that the bituminous pavement undergoes numerous vertical fluctuations and bending as the front and rear axles approached the point of measurement. The magnitude of the vertical displacement was measured via the means of an accelerometer and double integrator. When values of the dynamic deflections were in the magnitude of 0.07 through 0.10 inches, there was evidence of pavement failure. When the deflection values were above 0.10 inches pavement failures were distinct.

  12. Relationship between frequency and deflection angle in the DNA prism.

    PubMed

    Chen, Zhen; Dorfman, Kevin D

    2013-01-01

    The DNA prism is a modification of the standard pulsed-field electrophoresis protocol to provide a continuous separation, where the DNA are deflected at an angle that depends on their molecular weight. The standard switchback model for the DNA prism predicts a monotonic increase in the deflection angle as a function of the frequency for switching the field until a plateau regime is reached. However, experiments indicate that the deflection angle achieves a maximum value before decaying to a size-independent value at high frequencies. Using Brownian dynamics simulations, we show that the maximum in the deflection angle is related to the reorientation time for the DNA and the decay in deflection angle at high frequencies is due to inadequate stretching. The generic features of the dependence of the deflection angle on molecular weight, switching frequency, and electric field strength explain a number of experimental phenomena. PMID:23410375

  13. OTV bearing deflection investigation

    NASA Astrophysics Data System (ADS)

    Reimer, B. L.; Diepenbrock, R. T.; Millis, M. G.

    1993-04-01

    The primary goal of the Bearing Deflectometer Investigation was to gain experience in the use of fiber optic displacement probe technology for bearing health monitoring in a liquid hydrogen turbo pump. The work specified in this Task Order was conducted in conjunction with Air Force Rocket Propulsion Laboratory Contract F04611-86-C-0010. APD conducted the analysis and design coordination to provide a displacement probe design compatible with the XLR-134 liquid hydrogen turbo pump assembly (TPA). Specifications and requirements of the bearing deflectometer were established working with Mechanical Technology Instruments, Inc. (MTI). The TPA design accommodated positioning of the probe to measure outer race cyclic deflections of the pump inlet bearing. The fiber optic sensor was installed as required in the TPA and sensor output was recorded during the TPA testing. Data review indicated that no bearing deflection signature could be differentiated from the inherent system noise. Alternate sensor installations were not investigated, but might yield different results.

  14. A Second Life for CDs

    ERIC Educational Resources Information Center

    Snoderly, Kathleen

    2011-01-01

    Cutting a few CDs apart with scissors, the author found that the process created somewhat brittle shards. As a result, she started to paint a few with acrylic, finding to her amazement that the paint gave the CDs a leathery, more manageable texture. Upon further experimentation, she found that if the CDs are painted somewhat translucently in…

  15. Compact Superconducting Crabbing and Deflecting Cavities

    SciTech Connect

    De Silva, Payagalage Subashini Uddika

    2012-09-01

    Recently, new geometries for superconducting crabbing and deflecting cavities have been developed that have significantly improved properties over those the standard TM{sub 110} cavities. They are smaller, have low surface fields, high shunt impedance and, more importantly for some of them, no lower-order-mode with a well-separated fundamental mode. This talk will present the status of the development of these cavities.

  16. Photothermal deflection spectroscopy and detection

    SciTech Connect

    Jackson, W. B.; Amer, Nabil M.; Boccara, A. C.; Fournier, D.

    1981-04-15

    The theory for a sensitive spectroscopy based on the photothermal deflection of a laser beam is developed. We consider cw and pulsed cases of both transverse and collinear photothermal deflection spectroscopy for solids, liquids, gases, and thin films. The predictions of the theory are experimentally verified, its implications for imaging and microscopy are given, and the sources of noise are analyzed. The sensitivity and versatility of photothermal deflection spectroscopy are compared with thermal lensing and photoacoustic spectroscopy.

  17. AIDA: The Asteroid Impact & Deflection Assessment Mission

    NASA Astrophysics Data System (ADS)

    Galvez, A.; Carnelli, I.; Michel, P.; Cheng, A. F.; Reed, C.; Ulamec, S.; Biele, J.; Abell, P.; Landis, R.

    2013-09-01

    The Asteroid Impact and Deflection Assessment (AIDA) mission, a joint effort of ESA, JHU/APL, NASA, OCA, and DLR, is the first demonstration of asteroid deflection and assessment via kinetic impact. AIDA consists of two independent but mutually supporting mission elements, one of which is the asteroid kinetic impactor and the other is the characterization spacecraft. These two missions are, respectively, JHU/APL's Double Asteroid Redirection Test (DART) and the European Space Agency's Asteroid Investigation Mission (AIM) missions. As in the separate DART and AIM studies, the target of this mission is the binary asteroid [65803] Didymos in October, 2022. For a successful joint mission, one spacecraft, DART, would impact the secondary of the Didymos system while AIM would observe and measure any change in the relative orbit. AIM will be the first probe to characterise a binary asteroid, especially from the dynamical point of view, but also considering its interior and subsurface composition. The mission concept focuses on the monitoring aspects i.e., the capability to determine in-situ the key physical properties of a binary asteroid playing a role in the system's dynamic behavior. DART will be the first ever space mission to deflect the trajectory of an asteroid in a measurable way.- It is expected that the deflection can be measured as a change in the relative orbit period with a precision better than 10%. The joint AIDA mission will return vital data to determine the momentum transfer efficiency of the kinetic impact [1,2].

  18. A Simplified Soil-Structure Interaction Based Method for Calculating Deflection of Buried Pipe

    NASA Astrophysics Data System (ADS)

    Dhar, Ashutosh Sutra; Kabir, Md. Aynul

    Soil-pipe interaction analysis was performed using the continuum theory solution and the finite element method to develop simplified equations for deflection of buried flexible pipes. The hoop and bending components of pipe deflections were studied extensively to determine the influence of different soil and pipe parameters on deflection calculations. Then, two separate simplified equations were developed for the hoop and bending components of the pipe deflection. Two factors were incorporated in the equation for bending deflection to capture the effects of different parameters. Values of those factors were determined for steel and thermoplastic pipes. The proposed simplified equations logically incorporate the hoop and bending stiffness of the soil-pipe interaction.

  19. Directed energy deflection laboratory measurements

    NASA Astrophysics Data System (ADS)

    Brashears, Travis; Lubin, Phillip; Hughes, Gary B.; Meinhold, Peter; Suen, Jonathan; Batliner, Payton; Motta, Caio; Griswold, Janelle; Kangas, Miikka; Johansson, Isbella; Alnawakhtha, Yusuf; Prater, Kenyon; Lang, Alex; Madajian, Jonathan

    2015-09-01

    We report on laboratory studies of the effectiveness of directed energy planetary defense as a part of the DESTAR (Directed Energy System for Targeting of Asteroids and exploRation) program. DE-STAR [1][5][6] and DE-STARLITE [2][5][6] are directed energy "stand-off" and "stand-on" programs, respectively. These systems consist of a modular array of kilowatt-class lasers powered by photovoltaics, and are capable of heating a spot on the surface of an asteroid to the point of vaporization. Mass ejection, as a plume of evaporated material, creates a reactionary thrust capable of diverting the asteroid's orbit. In a series of papers, we have developed a theoretical basis and described numerical simulations for determining the thrust produced by material evaporating from the surface of an asteroid [1][2][3][4][5][6]. In the DE-STAR concept, the asteroid itself is used as the deflection "propellant". This study presents results of experiments designed to measure the thrust created by evaporation from a laser directed energy spot. We constructed a vacuum chamber to simulate space conditions, and installed a torsion balance that holds an "asteroid" sample. The sample is illuminated with a fiber array laser with flux levels up to 60 MW/m2 which allows us to simulate a mission level flux but on a small scale. We use a separate laser as well as a position sensitive centroid detector to readout the angular motion of the torsion balance and can thus determine the thrust. We compare the measured thrust to the models. Our theoretical models indicate a coupling coefficient well in excess of 100 μN/Woptical, though we assume a more conservative value of 80 μN/Woptical and then degrade this with an optical "encircled energy" efficiency of 0.75 to 60 μN/Woptical in our deflection modeling. Our measurements discussed here yield about 45 μN/Wabsorbed as a reasonable lower limit to the thrust per optical watt absorbed.

  20. A small-gap electrostatic micro-actuator for large deflections

    PubMed Central

    Conrad, Holger; Schenk, Harald; Kaiser, Bert; Langa, Sergiu; Gaudet, Matthieu; Schimmanz, Klaus; Stolz, Michael; Lenz, Miriam

    2015-01-01

    Common quasi-static electrostatic micro actuators have significant limitations in deflection due to electrode separation and unstable drive regions. State-of-the-art electrostatic actuators achieve maximum deflections of approximately one third of the electrode separation. Large electrode separation and high driving voltages are normally required to achieve large actuator movements. Here we report on an electrostatic actuator class, fabricated in a CMOS-compatible process, which allows high deflections with small electrode separation. The concept presented makes the huge electrostatic forces within nanometre small electrode separation accessible for large deflections. Electrostatic actuations that are larger than the electrode separation were measured. An analytical theory is compared with measurement and simulation results and enables closer understanding of these actuators. The scaling behaviour discussed indicates significant future improvement on actuator deflection. The presented driving concept enables the investigation and development of novel micro systems with a high potential for improved device and system performance. PMID:26655557

  1. Noncontact measurement of angular deflection

    NASA Technical Reports Server (NTRS)

    Bryant, E. L.

    1978-01-01

    Technique for measuring instantaneous angular deflection of object requires no physical contact. Technique utilizes two flat refractors, converging lens, and different photocell. Distinction of method is its combination of optical and electromechanical components into feedback system in which measurement error is made to approach zero. Application is foreseen in measurement of torsional strain.

  2. New concepts of electro-optical light deflection: EO-slab and phased EO-array

    NASA Astrophysics Data System (ADS)

    Wirth, Volker; Krasnaberski, Alexei; Ivanenko, Mikhail

    2015-03-01

    Deflection and modulation of a laser beam for Q-switching or material processing can be realized in many ways. Today, one task is still the speed of these components. Especially for spatial pulse separation in ultrashort pulse laser applications the deflection must be faster (MHz). Promising solutions are deflectors based on the electro-optic effect.

  3. AIDA: Asteroid Impact & Deflection Assessment

    NASA Astrophysics Data System (ADS)

    Cheng, A. F.; Galvez, A.; Carnelli, I.; Michel, P.; Rivkin, A.; Reed, C.

    2012-12-01

    To protect the Earth from a hazardous asteroid impact, various mitigation methods have been proposed, including deflection of the asteroid by a spacecraft impact. AIDA, consisting of two mission elements, the Double Asteroid Redirection Test (DART) and the Asteroid Impact Monitoring (AIM) mission, is a demonstration of asteroid deflection. To date, there has been no such demonstration, and there is major uncertainty in the result of a spacecraft impact onto an asteroid, that is, the amount of deflection produced by a given momentum input from the impact. This uncertainty is in part due to unknown physical properties of the asteroid surface, such as porosity and strength, and in part due to poorly understood impact physics such that the momentum carried off by ejecta is highly uncertain. A first mission to demonstrate asteroid deflection would not only be a major step towards gaining the capability to mitigate an asteroid hazard, but in addition it would return unique information on an asteroid's strength, other surface properties, and internal structure. This information return would be highly relevant to future human exploration of asteroids. We report initial results of the AIDA joint mission concept study undertaken by the Johns Hopkins Applied Physics Laboratory and ESA with support from NASA centers including Goddard, Johnson and Jet Propulsion Laboratory. For AIDA, the DART spacecraft impactor study is coordinated with an ESA study of the AIM mission, which would rendezvous with the same asteroid to measure effects of the impact. Unlike the previous Don Quijote mission study performed by ESA in 2005-2007, DART envisions an impactor spacecraft to intercept the secondary member of a binary near-Earth asteroid. DART includes ground-based observations to measure the deflection independently of the rendezvous spacecraft observations from AIM, which also measures deflection and provides detailed characterization of the target asteroid. The joint mission AIDA

  4. Elevator deflections on the icing process

    NASA Technical Reports Server (NTRS)

    Britton, Randall K.

    1990-01-01

    The effect of elevator deflection of the horizontal stabilizer for certain icing parameters is investigated. Elevator deflection can severely change the lower and upper leading-edge impingement limits, and ice can accrete on the elevator itself. Also, elevator deflection had practically no effect on the maximum local collection efficiency. It is shown that for severe icing conditions (large water droplets), elevator deflections that increase the projected height of the airfoil can significantly increase the total collection efficiency of the airfoil.

  5. The Seven Habits of Highly Deflective Colleagues

    ERIC Educational Resources Information Center

    Maher, Michelle; Chaddock, Katherine

    2009-01-01

    The authors define deflection as a strategy to bounce action or responsibility away from oneself and toward another person, time, or place. Although they contend that deflection occurs in all areas of personal and professional life, the authors limit their focus to the deflective colleague ("collega deflectivus") in academe. In this article, the…

  6. Using Photo CDs for Instruction.

    ERIC Educational Resources Information Center

    Yeamans, George T.

    1994-01-01

    Describes the use of Kodak's Photo CD for teaching, testing, and practicing basic concepts of photography and composition based on experiences at Ball State University, Muncie, Indiana. The use of practice disks is explained, learning outcomes and student attitudes are discussed, and a sidebar describes new software for use with Photo CDs. (LRW)

  7. Novel deflecting cavity design for eRHIC

    SciTech Connect

    Wu, Q.; Belomestnykh, S.; Ben-Zvi, I.

    2011-07-25

    To prevent significant loss of the luminosity due to large crossing angle in the future ERL based Electron Ion Collider at BNL (eRHIC), there is a demand for crab cavities. In this article, we will present a novel design of the deflecting/crabbing 181 MHz superconducting RF cavity that will fulfil the requirements of eRHIC. The quarter-wave resonator structure of the new cavity possesses many advantages, such as compact size, high R{sub t}/Q, the absence of the same order mode and lower order mode, and easy higher order mode damping. We will present the properties and characteristics of the new cavity in detail. As the accelerator systems grow in complexity, developing compact and efficient deflecting cavities is of great interest. Such cavities will benefit situations where the beam line space is limited. The future linac-ring type electron-ion collider requires implementation of a crab-crossing scheme for both beams at the interaction region. The ion beam has a long bunches and high rigidity. Therefore, it requires a low frequency, large kicking angle deflector. The frequency of the deflecting mode for the current collider design is 181 MHz, and the deflecting angle is {approx}5 mrad for each beam. At such low frequency, the previous designs of the crab cavities will have very large dimensions, and also will be confronted by typical problems of damping the Lower Order Mode (LOM), the Same Order Mode (SOM), and as usual, the Higher Order Modes (HOM). In this paper we describe how one can use the concept of a quarter-wave (QW) resonator for a deflecting/crabbing cavity, and use its fundamental mode to deflect the beam. The simplicity of the cavity geometry and the large separation between its fundamental mode and the first HOM make it very attractive.

  8. Modeling rectangular cantilevers during torsion and deflection for application to frictional force microscopy.

    PubMed

    Hayden, Victor C; Beaulieu, Luc Y

    2009-06-01

    A numerical and experimental analysis of the optical beam deflection system used to monitor microcantilevers subjected to simultaneous deflection and twisting such as in lateral or frictional force microscopy was performed. This study focused on two optical beam deflection orientations where in the first case the optical beam and the detector are at a right angle to the length of the cantilever and the second case, which is the more standard orientation, the optical beam is parallel to the length of the lever. This study finds that it is possible to model the twist and the deflection separately and treat each motion independently. Simulations have shown that the above-mentioned systems are equivalent in accuracy and sensitivity for monitoring the simultaneous twist and deflection of cantilevers. PMID:19460183

  9. Mechanistic interpretation of nondestructive pavement testing deflections

    NASA Astrophysics Data System (ADS)

    Hoffman, M. S.

    1980-06-01

    A method is proposed for the backcalculation of material properties in flexible pavements based on the interpretation of surface deflection measurements. ILLI-PAVE, a stress dependent finite element pavement model, was used to generate data for developing algorithms and nomographs for deflection basin interpretation. Over 11,000 deflection measurements for 24 different flexible pavement sections were collected and analyzed. Deflections were measured using the Benkelman Beam, the IDOT Road Rater, the Falling Weight Deflectometer, and an accelerometer to measure deflections under moving trucks. Loading mode effects on pavement response were investigated using dynamic and viscous pavement models. The factors controlling the pavement response to different loading modes were explained and identified. Correlations between different devices were developed. The proposed evaluation procedure is illustrated for three different flexible pavements using deflection data collected on several testing dates.

  10. Measurement of Deflection Line on Bridges

    NASA Astrophysics Data System (ADS)

    Urban, Rudolf; Štroner, Martin

    2013-12-01

    Prestressed concrete bridges are very sensitive to the increase in long-term deflections. Reliable forecasts of deflections of bridge structures during construction and durability are crucial for achieving good durability. The main results of measurements are the changes of the deflection line of the bridge structures, which places special demands on the measurement procedure. Results from measurements are very useful for the improvement of mathematical prediction methods of behaviour of long span prestressed concrete structures.

  11. Multipole Field Effects for the Superconducting Parallel-Bar Deflecting/Crabbing Cavities

    SciTech Connect

    De Silva, Payagalage Subashini Uddika; Delayen, Jean Roger

    2012-09-01

    The superconducting parallel-bar deflecting/crabbing cavity is currently being considered as one of the design options in rf separation for the Jefferson Lab 12 GeV upgrade and for the crabbing cavity for the proposed LHC luminosity upgrade. Knowledge of multipole field effects is important for accurate beam dynamics study of rf structures. The multipole components can be accurately determined numerically using the electromagnetic surface field data in the rf structure. This paper discusses the detailed analysis of those components for the fundamental deflecting/crabbing mode and higher order modes in the parallel-bar deflecting/crabbing cavity.

  12. Laser deflection of space objects -- An overview

    SciTech Connect

    Canavan, G.H.

    1997-04-01

    Lasers provide the two major attributes required for effective deflection of space objects: agility and efficiency. Lasers act instantaneously over long distances with little losses, but deliver energy at modest power levels. Material interceptors provide large impulses, but deliver only a fraction of the mass launched into space at low speeds. The two deflection concepts are compared, as are some important additional applications.

  13. Horizontal deflection of single particle in a paramagnetic fluid.

    PubMed

    Liu, S; Yi, Xiang; Leaper, M; Miles, N J

    2014-06-01

    This paper describes the horizontal deflection behaviour of a single particle in paramagnetic fluids under a high-gradient superconducting magnetic field. A glass box was designed to carry out experiments and test assumptions. It was found that the particles were deflected away from the magnet bore centre and particles with different density and/or susceptibility settled at a certain position on the container floor due to the combined forces of gravity and magneto-Archimedes as well as lateral buoyant (displacement) force. Matlab was chosen to simulate the movement of the particle in the magnetic fluid, the simulation results were in good accordance with experimental data. The results presented here, though, are still very much in their infancy, which could potentially form the basis of a new approach to separating materials based on a combination of density and susceptibility. PMID:24894886

  14. SUPERCONDUCTING RF-DIPOLE DEFLECTING AND CRABBING CAVITIES

    SciTech Connect

    Delayen, Jean; De Silva, Paygalage Subashini

    2013-09-01

    Recent interests in designing compact deflecting and crabbing structures for future accelerators and colliders have initiated the development of novel rf structures. The superconducting rf-dipole cavity is one of the first compact designs with attractive properties such as higher gradients, higher shunt impedance, the absence of lower order modes and widely separated higher order modes. Two rf-dipole designs of 400 MHz and 499 MHz have been designed, fabricated and tested as proof-of-principle designs of compact deflecting and crabbing cavities for the LHC high luminosity upgrade and Jefferson Lab 12 GeV upgrade. The first rf tests have been performed on the rf-dipole geometries at 4.2 K and 2.0 K in a vertical test assembly with excellent results. The cavities have achieved high gradients with high intrinsic quality factors, and multipacting levels were easily processed.

  15. Isotope separation

    DOEpatents

    Bartlett, Rodney J.; Morrey, John R.

    1978-01-01

    A method and apparatus is described for separating gas molecules containing one isotope of an element from gas molecules containing other isotopes of the same element in which all of the molecules of the gas are at the same electronic state in their ground state. Gas molecules in a gas stream containing one of the isotopes are selectively excited to a different electronic state while leaving the other gas molecules in their original ground state. Gas molecules containing one of the isotopes are then deflected from the other gas molecules in the stream and thus physically separated.

  16. AIDA: the Asteroid Impact & Deflection Assessment mission

    NASA Astrophysics Data System (ADS)

    Vincent, Jean-Baptiste

    2016-07-01

    The Asteroid Impact & Deflection Assessment (AIDA) mission is a joint cooperation between European and US space agencies that consists of two separate and independent spacecraft that will be launched to a binary asteroid system, the near-Earth asteroid Didymos, to assess the possibility of deflecting an asteroid trajectory by using a kinetic impactor. The European Asteroid Impact Mission (AIM) is under Phase A/B1 study at ESA from March 2015 until summer 2016. AIM is set to rendez-vous with the asteroid system a few months prior to the impact by the US Double Asteroid Redirection Test (DART) spacecraft to fully characterize the smaller of the two binary components. AIM is a unique mission as it will be the first time that a spacecraft will investigate the surface, subsurface, and internal properties of a small binary near Earth asteroid. In addition it will perform various important technology demonstrations that can serve other space missions: AIM will release a set of CubeSats in deep space and a lander on the surface of the smaller asteroid and for the first time, deep-space inter-satellite linking will be demonstrated between the main spacecraft, the CubeSats, and the lander, and data will also be transmitted from interplanetary space to Earth by a laser communication system. The knowledge obtained by this mission will have great implications for our understanding of the history of the Solar System. Small asteroids are believed to result from collisions and other processes (e.g., spinup, shaking) that made them what they are now. Having direct information on their surface and internal properties will allow us to understand how these processes work and transform these small bodies as well as, for this particular case, how a binary system forms. So far, our understanding of the collisional process and the validation of numerical simulations of the impact process rely on impact experiments at laboratory scales. With DART, thanks to the characterization of the

  17. Matter Wave Deflection through a Light Prism

    NASA Astrophysics Data System (ADS)

    Ronan, Joseph; Cronin, Alexander; Holmgren, William; Hromada, Ivan; Trubko, Raisa

    2011-10-01

    In optics, it is a well-known fact that a glass prism will bend a light beam incident on its surface. We present an atom optics experiment analogous to this phenomenon, but instead we use a light prism to deflect a beam of potassium atoms. We use a Mach-Zehnder atom interferometer to precisely measure atom beam deflections of as small as 5 nm. Through studying the beam deflection, we are able to investigate the dynamic polarizability and the magic zero wavelength of potassium.

  18. Noncontacting method for measuring angular deflection

    NASA Technical Reports Server (NTRS)

    Bryant, E. L. (Inventor)

    1980-01-01

    An apparatus is described for indicating the instantaneous angular deflection of an object about a selected axis without mechanical contact with the object. Light from a light source is transmitted through a flat refractor to a converging lens which focuses the light through another flat refractor onto a differential photocell. The first flat refractor is attached to the object such that when the object is deflected about the selected axis the refractor is also deflected about that axis. The two flat refractors are identical and they are placed an equal distance from the converging lens as are the light source and the photocell. The output of the photocell which is a function of image displacement is fed to a high gain amplifier that drives a galvanometer which rotates the second flat refractor. The second refractor is rotated so that the image displacement is very nearly zero making the galvanometer current a measure of the deflection of the object about the selected axis.

  19. Optical measurement of unducted fan blade deflections

    NASA Technical Reports Server (NTRS)

    Kurkov, Anatole P.

    1988-01-01

    A nonintrusive optical method for measuring unducted fan (or propeller) blade deflections is described and evaluated. The measurement does not depend on blade surface reflectivity. Deflection of a point at the leading edge and a point at the trailing edge in a plane nearly perpendicular to the pitch axis is obtained with a single light beam generated by a low-power, helium-neon laser. Quantitiative analyses are performed from taped signals on a digital computer. Averaging techniques are employed to reduce random errors. Measured static deflections from a series of high-speed wind tunnel tests of a counterrotating unducted fan model are compared with available, predicted deflections, which are also used to evaluate systematic errors.

  20. Optical measurement of propeller blade deflections

    NASA Technical Reports Server (NTRS)

    Kurkov, Anatole P.

    1988-01-01

    A nonintrusive optical method for measurement of propeller blade deflections is described and evaluated. It does not depend on the reflectivity of the blade surface but only on its opaqueness. Deflection of a point at the leading edge and a point at the trailing edge in a plane nearly perpendicular to the pitch axis is obtained using a single light beam generated by a low-power helium-neon laser. Quantitative analyses are performed from taped signals on a digital computer. Averaging techniques are employed to reduce random errors. Measured deflections from a static and a high-speed test are compared with available predicted deflections which are also used to evaluate systematic errors.

  1. Miniaturization of flight deflection measurement system

    NASA Technical Reports Server (NTRS)

    Fodale, Robert (Inventor); Hampton, Herbert R. (Inventor)

    1990-01-01

    A flight deflection measurement system is disclosed including a hybrid microchip of a receiver/decoder. The hybrid microchip decoder is mounted piggy back on the miniaturized receiver and forms an integral unit therewith. The flight deflection measurement system employing the miniaturized receiver/decoder can be used in a wind tunnel. In particular, the miniaturized receiver/decoder can be employed in a spin measurement system due to its small size and can retain already established control surface actuation functions.

  2. Shielded serpentine traveling wave tube deflection structure

    DOEpatents

    Hudson, C.L.; Spector, J.

    1994-12-27

    A shielded serpentine slow wave deflection structure is disclosed having a serpentine signal conductor within a channel groove. The channel groove is formed by a serpentine channel in a trough plate and a ground plane. The serpentine signal conductor is supported at its ends by coaxial feed through connectors. A beam interaction trough intersects the channel groove to form a plurality of beam interaction regions wherein an electron beam may be deflected relative to the serpentine signal conductor. 4 figures.

  3. Deflection Sensors Utilizing Optical Multi-Stability

    NASA Astrophysics Data System (ADS)

    Shehadeh, Shadi H.; Cada, Michael; Qasymeh, Montasir; Ma, Yuan

    2010-06-01

    Deflection sensors have attracted significant attention due to their wide application in pressure and temperature measurements in practical systems. Several techniques have been proposed, studied, and tested to realize optical deflection sensor elements, including Mach-Zehnder (MZI), and Fabry-Pérot interferometers. In this work, a novel optical deflection sensor that is comprised of two cascaded optical resonators is proposed and analyzed. The proposed structure is designed to operate in the multi-stable (input to output) regime. As the first resonator is equipped with a movable mirror, which is connected to a diaphragm in order to sense changes in deflection, the second resonator is filled with non-linear material. It is demonstrated that such a structure has a novel memory property, aside from having the ability to yield instant deflection measurements. This novel property is attributed to the non-linear refractive index of the medium of the second resonator. Furthermore, the sensor sensitivity (which is the ratio of the change in the output light intensity to the change in the induced deflection) is enhanced due to the input-output multi-stable behavior of the proposed structure. This device possesses a promising potential for applications in future smart sensors.

  4. The deflection of 2008 December 12 CME

    NASA Astrophysics Data System (ADS)

    Shen, C.; Wang, Y.; Liu, J.; Ye, P.; Wang, S.

    2010-12-01

    The deflection of CME, which would significant influence the CME's geoeffectiveness, is an important topic of space weather study. In this work, the deflection of 2008 December 12 CME during it propagated from the Sun to Earth will be detailed studied based on the combination of remote and in situ observations. First, the 3-dimensions parameters reconstructed by Graduated Cylindrical Shell (GCS) model based on the STEREO observations were used to study the propagation direction evolution of this CME during it propagated in near solar space. During this phase, this CME deflect from high latitude region to equator in meridian plane but propagated almost along the longitude of W7 in ecliptic plane. Further, whether this CME deflected during it propagated in interplanetary space has also been checked. Based on the remote observations, if this CME propagated radially during it propagated in interplanetary space, it may arrived the Earth and then hit the STEREO A rather than hit STEREO B. But, the in situ observations show contrary results that this CME arrived the Earth and hit the STEREO B but missed STEREO A. This result show direct evidence that this CME deflected to east in ecliptic plane during it propagated in interplanetary space. The kinematic deflection model developed by Wang et. al (2004) has been applied on this CME. The calculation results of this model correspond well with the observational results.

  5. Growth of CdS Nanorods and Deposition of Silver Nanoparticles.

    PubMed

    Zhao, Jie; Yang, Fanghong; Yang, Ping

    2015-05-01

    Systematic investigations have been done to deposit silver nanoparticles on seeded CdS nanorods. The CdS nanorods were synthesized by using CdS nanocrystals as seeds being indexed to the cubic structure (zinc-blende) and tetradecylphosphonic acid as surfactants to enable preferential growth on the reactive {001} facets. Ostwald ripening process occurred during the growth of CdS nanorods. Ag/CdS heterostructures were obtained through a facile method in which oleylamine was employed as reducing agents under an elevated temperature. Exposing CdS nanorods to Ag+ ions resulted in Ag domains depositing on the tips of the nanorods or defected sites embedding in the nanorod surfaces. Ag domains formed separate nuclei and grew quickly at a high concentration of AgNO3 solution. We further focused on discussing the morphology formation mechanism and optical properties of the heterostructures and the nanorods. The as-synthesized Ag/CdS heterostructures can facilitate charge separation at the metal-semiconductor interface. Herein, it opens up an application possibility of enhancing photocatalytic processes and other devices. PMID:26505026

  6. Deflection unit for multi-beam mask making

    NASA Astrophysics Data System (ADS)

    Letzkus, Florian; Butschke, Joerg; Irmscher, Mathias; Jurisch, Michael; Klingler, Wolfram; Platzgummer, Elmar; Klein, Christof; Loeschner, Hans; Springer, Reinhard

    2008-10-01

    Two main challenges of future mask making are the decreasing throughput of the pattern generators and the insufficient line edge roughness of the resist structures. The increasing design complexity with smaller feature sizes combined with additional pattern elements of the Optical Proximity Correction generates huge data volumes which reduce correspondingly the throughput of conventional single e-beam pattern generators. On the other hand the achievable line edge roughness when using sensitive chemically amplified resists does not fulfill the future requirements. The application of less sensitive resists may provide an improved roughness, however on account of throughput, as well. To overcome this challenge a proton multi-beam pattern generator is developed [1]. Starting with a highly parallel broad beam, an aperture-plate is used to generate thousands of separate spot beams. These beams pass through a blanking-plate unit, based on a CMOS device for de-multiplexing the writing data and equipped with electrodes placed around the apertures switching the beams "on" or "off", dependent on the desired pattern. The beam array is demagnified by a 200x reduction optics and the exposure of the entire substrate is done by a continuous moving stage. One major challenge is the fabrication of the required high aspect deflection electrodes and their connection to the CMOS device. One approach is to combine a post-processed CMOS chip with a MEMS component containing the deflection electrodes and to realize the electrical connection of both by vertical integration techniques. For the evaluation and assessment of this considered scheme and fabrication technique, a proof-of-concept deflection unit has been realized and tested. Our design is based on the generation of the deflection electrodes in a silicon membrane by etching trenches and oxide filling afterwards. In a 5mm x 5mm area 43,000 apertures with the corresponding electrodes have been structured and wired individually or in

  7. Brachytherapy needle deflection evaluation and correction

    SciTech Connect

    Wan Gang; Wei Zhouping; Gardi, Lori; Downey, Donal B.; Fenster, Aaron

    2005-04-01

    In prostate brachytherapy, an 18-gauge needle is used to implant radioactive seeds. This thin needle can be deflected from the preplanned trajectory in the prostate, potentially resulting in a suboptimum dose pattern and at times requiring repeated needle insertion to achieve optimal dosimetry. In this paper, we report on the evaluation of brachytherapy needle deflection and bending in test phantoms and two approaches to overcome the problem. First we tested the relationship between needle deflection and insertion depth as well as whether needle bending occurred. Targeting accuracy was tested by inserting a brachytherapy needle to target 16 points in chicken tissue phantoms. By implanting dummy seeds into chicken tissue phantoms under 3D ultrasound guidance, the overall accuracy of seed implantation was determined. We evaluated methods to overcome brachytherapy needle deflection with three different insertion methods: constant orientation, constant rotation, and orientation reversal at half of the insertion depth. Our results showed that needle deflection is linear with needle insertion depth, and that no noticeable bending occurs with needle insertion into the tissue and agar phantoms. A 3D principal component analysis was performed to obtain the population distribution of needle tip and seed position relative to the target positions. Our results showed that with the constant orientation insertion method, the mean needle targeting error was 2.8 mm and the mean seed implantation error was 2.9 mm. Using the constant rotation and orientation reversal at half insertion depth methods, the deflection error was reduced. The mean needle targeting errors were 0.8 and 1.2 mm for the constant rotation and orientation reversal methods, respectively, and the seed implantation errors were 0.9 and 1.5 mm for constant rotation insertion and orientation reversal methods, respectively.

  8. Management of Catalogs at CDS

    NASA Astrophysics Data System (ADS)

    Landais, G.; Boch, T.; Brouty, M.; Guéhenneux, S.; Genova, F.; Lesteven, S.; Ochsenbein, F.; Ocvirk, P.; Perret, E.; Pineau, F.-X.; Simon, A.-C.; Vannier, P.

    2015-04-01

    VizieR (Ochsenbein et al. 2000) provides access to the most complete library of published astronomical catalogs (data tables and associated data) available online and organized in a self-documented database. (There were 11769 catalogs in November 2013.) Indexing the metadata in the VizieR search engine requires the expertise of scientists and documentalists for each catalog ingested. The metadata go into an efficient position search engine that is adapted to big data. (For instance, the GAIA simulation catalog has more than two billion objects). Information in VizieR tables is well described and can be retrieved easily. The search results provide visibility to catalogs with tools and protocols to disseminate data to the Virtual Observatory, thus giving scientists data that is reusable by dedicated tools (e.g. image vizualisation tools). Also, new functionality allows users to extract all photometric data in catalogs for a given position. Finally, it is also through cross-identification tools that the CDS becomes a partner in producing large data sets, such as GAIA.

  9. Lateral-deflection-controlled friction force microscopy

    NASA Astrophysics Data System (ADS)

    Fukuzawa, Kenji; Hamaoka, Satoshi; Shikida, Mitsuhiro; Itoh, Shintaro; Zhang, Hedong

    2014-08-01

    Lateral-deflection-controlled dual-axis friction force microscopy (FFM) is presented. In this method, an electrostatic force generated with a probe-incorporated micro-actuator compensates for friction force in real time during probe scanning using feedback control. This equivalently large rigidity can eliminate apparent boundary width and lateral snap-in, which are caused by lateral probe deflection. The method can evolve FFM as a method for quantifying local frictional properties on the micro/nanometer-scale by overcoming essential problems to dual-axis FFM.

  10. Transverse photothermal beam deflection within a solid

    SciTech Connect

    Spear, J.D.; Russo, R.E. )

    1991-07-15

    The mirage effect within a transparent solid substrate was used for monitoring optical absorption of a thin film. Refractive index gradients, which accompany thermal gradients below the film-coated surface, cause a probe laser beam to be deflected. The spectrum of copper, deposited onto a piece of clear acrylic, was recorded by this method of photothermal deflection. The influence of thermally induced mechanical stresses can alter the effective value of the thermo-optic coefficient of the solid, {ital dn}/{ital dT}.

  11. Light deflection in gadolinium molybdate ferroelastic crystals

    NASA Astrophysics Data System (ADS)

    Staniorowski, Piotr; Bornarel, Jean

    2000-02-01

    The deflection of a He-Ne light beam by polydomain gadolinium molybdate (GMO) crystals has been studied with respect to incidence angle icons/Journals/Common/alpha" ALT="alpha" ALIGN="TOP"/> i on the sample at room temperature. The A and B deflected beams do not cross each other during the icons/Journals/Common/alpha" ALT="alpha" ALIGN="TOP"/> i variation, in contrast to results and calculations previously published. The model using the Fresnel equation confirms this result. The model presented is more accurate for numerical calculation than that using the Huygens construction.

  12. Deflection of large near-earth objects

    SciTech Connect

    Canavan, G.H.

    1999-01-11

    The Earth is periodically hit by near Earth objects (NEOs) ranging in size from dust to mountains. The small ones are a useful source of information, but those larger than about 1 km can cause global damage. The requirements for the deflection of NEOs with significant material strength are known reasonably well; however, the strength of large NEOs is not known, so those requirements may not apply. Meteor impacts on the Earth`s atmosphere give some information on strength as a function of object size and composition. This information is used here to show that large, weak objects could also be deflected efficiently, if addressed properly.

  13. Shielded serpentine traveling wave tube deflection structure

    DOEpatents

    Hudson, Charles L.; Spector, Jerome

    1994-01-01

    A shielded serpentine slow wave deflection structure (10) having a serpene signal conductor (12) within a channel groove (46). The channel groove (46) is formed by a serpentine channel (20) in a trough plate (18) and a ground plane (14). The serpentine signal conductor (12) is supported at its ends by coaxial feed through connectors 28. A beam interaction trough (22) intersects the channel groove (46) to form a plurality of beam interaction regions (56) wherein an electron beam (54) may be deflected relative to the serpentine signal conductor (12).

  14. Correct light deflection in Weyl conformal gravity

    NASA Astrophysics Data System (ADS)

    Cattani, Carlo; Scalia, Massimo; Laserra, Ettore; Bochicchio, Ivana; Nandi, Kamal K.

    2013-02-01

    The conformal gravity fit to observed galactic rotation curves requires γ>0. On the other hand, the conventional method for light deflection by galaxies gives a negative contribution to the Schwarzschild value for γ>0, which is contrary to observation. Thus, it is very important that the contribution to bending should in principle be positive, no matter how small its magnitude is. Here we show that the Rindler-Ishak method gives a positive contribution to Schwarzschild deflection for γ>0, as desired. We also obtain the exact local coupling term derived earlier by Sereno. These results indicate that conformal gravity can potentially test well against all astrophysical observations to date.

  15. Rural Youth and Anticipatory Goal Deflection.

    ERIC Educational Resources Information Center

    Curry, Evans W.; And Others

    Race, sex, community size, occupation of major wage earner, father's education, mother's education, and certainty of expectations were the variables used in this study to determine the "anticipatory occupational goal deflection" (AOGD) of urban and rural youth (blacks and whites) in Louisiana. Least squares analysis of variance and other…

  16. Laboratory experiments on arc deflection and instability

    SciTech Connect

    Zweben, S.; Karasik, M.

    2000-03-21

    This article describes experiments on arc deflection instability carried out during the past few years at the Princeton University Plasma Physics Laboratory (PPPL). The approach has been that of plasma physicists interested in arcs, but they believe these results may be useful to engineers who are responsible for controlling arc behavior in large electric steel furnaces.

  17. Simplified deflection-coil linearity testing

    NASA Technical Reports Server (NTRS)

    Kramer, G. P.

    1976-01-01

    Mask placed over face of image-dissecting photomultiplier tube has precision array of pinholes that permit light to impinge on tube at known points. Signals are fed to deflection coil which sweeps beam across each point without complex operator procedures.

  18. Measuring Deflections Of Propeller And Fan Blades

    NASA Technical Reports Server (NTRS)

    Kurkov, Anatole P.

    1993-01-01

    Method based on measurement of interruptions of laser beam provides information on deflections of blades of airplane propeller or unducted turbofan. Bends and twists deduced from timing of laser-beam shadows. Provides for nonintrusive measurement in wind tunnel or on open test stand.

  19. Impeller deflection and modal finite element analysis.

    SciTech Connect

    Spencer, Nathan A.

    2013-10-01

    Deflections of an impeller due to centripetal forces are calculated using finite element analysis. The lateral, or out of plane, deflections are an important design consideration for this particular impeller because it incorporates an air bearing with critical gap tolerances. The target gap distance is approximately 10 microns at a rotational velocity of 2500 rpm. The centripetal forces acting on the impeller cause it deflect in a concave fashion, decreasing the initial gap distance as a function of radial position. This deflection is characterized for a previous and updated impeller design for comparative purposes. The impact of design options such as material selection, geometry dimensions, and operating rotational velocity are also explored, followed by a sensitivity study with these parameters bounded by specific design values. A modal analysis is also performed to calculate the impeller's natural frequencies which are desired to be avoided during operation. The finite element modeling techniques continue to be exercised by the impeller design team to address specific questions and evaluate conceptual designs, some of which are included in the Appendix.

  20. Particle beam and crabbing and deflecting structure

    DOEpatents

    Delayen, Jean

    2011-02-08

    A new type of structure for the deflection and crabbing of particle bunches in particle accelerators comprising a number of parallel transverse electromagnetic (TEM)-resonant) lines operating in opposite phase from each other. Such a structure is significantly more compact than conventional crabbing cavities operating the transverse magnetic TM mode, thus allowing low frequency designs.

  1. Improved laser ablation model for asteroid deflection

    NASA Astrophysics Data System (ADS)

    Vasile, Massimiliano; Gibbings, Alison; Watson, Ian; Hopkins, John-Mark

    2014-10-01

    This paper presents an improved laser ablation model and compares the performance - momentum coupling and deflection system mass - of laser ablation against contactless deflection methods based on ion-propulsion. The deflection of an asteroid through laser ablation is achieved by illuminating the surface of the asteroid with high intensity laser light. The absorbed energy induces the sublimation of the surface material and the generation of a plume of gas and ejecta. Similar to a rocket engine, the flow of expelled material produces a continuous and controllable thrust that could be used to modify the trajectory and tumbling motion of the asteroid. Recent results gained from a series of laser ablation experiments were used to improve the sublimation and deflection models. In each experiment a terrestrial olivine sample was ablated, under vacuum, with a 90 W continuous wave laser. The paper presents a model that better fits the outcomes of the experimental campaign, in particular in terms of mass flow rate and spot temperature.

  2. Enhancement of Charge Transfer and Quenching of Photoluminescence of Capped CdS Quantum Dots

    PubMed Central

    Mehata, Mohan Singh

    2015-01-01

    Quantum dots (Q-dots) of cadmium sulfide (CdS) with three different capping ligands, 1-butanethiol (BT), 2-mercaptoethanol (ME) and benzyl mercaptan (BM) have been investigated. An external electric field of variable strength of 0.2–1.0 MV cm−1 was applied to the sample of capped CdS Q-dots doped in a poly(methyl methacrylate) (PMMA) films. Field-induced changes in optical absorption of capped CdS Q-dots were observed in terms of purely the second-derivative of the absorption spectrum (the Stark shift), indicating an enhancement in electric dipole moment following transition to the first exciton state. The enhancement depends on the shape and size of the Q-dots prepared using different capping ligands. Field induced-change in photoluminescence (PL) reveals similar changes, an enhancement in charge-transfer (CT) character in exciton state. PL of capped CdS Q-dots is significantly quenched in presence of external electric field. The strong field-induced quenching occurs as a result of the increased charge separation resulting exciton dissociation. Thus, understanding the CT character and field-induced PL quenching of CdS Q-dots is important for photovoltaic, LEDs and biological applications. PMID:26166553

  3. Large beam deflection using cascaded prism array

    NASA Astrophysics Data System (ADS)

    Wang, Wei-Chih; Tsui, Chi-Leung

    2012-04-01

    Endoscopes have been utilize in the medical field to observe the internals of the human body to assist the diagnosis of diseases, such as breathing disorders, internal bleeding, stomach ulcers, and urinary tract infections. Endoscopy is also utilized in the procedure of biopsy for the diagnosis of cancer. Conventional endoscopes suffer from the compromise between overall size and image quality due to the required size of the sensor for acceptable image quality. To overcome the size constraint while maintaining the capture image quality, we propose an electro-optic beam steering device based on thermal-plastic polymer, which has a small foot-print (~5mmx5mm), and can be easily fabricated using conventional hot-embossing and micro-fabrication techniques. The proposed device can be implemented as an imaging device inside endoscopes to allow reduction in the overall system size. In our previous work, a single prism design has been used to amplify the deflection generated by the index change of the thermal-plastic polymer when a voltage is applied; it yields a result of 5.6° deflection. To further amplify the deflection, a new design utilizing a cascading three-prism array has been implemented and a deflection angle to 29.2° is observed. The new design amplifies the beam deflection, while keeping the advantage of simple fabrication made possible by thermal-plastic polymer. Also, a photo-resist based collimator lens array has been added to reduce and provide collimation of the beam for high quality imaging purposes. The collimator is able to collimate the exiting beam at 4 μm diameter for up to 25mm, which potentially allows high resolution image capturing.

  4. Asteroid Impact & Deflection Assessment mission: Kinetic impactor

    NASA Astrophysics Data System (ADS)

    Cheng, A. F.; Michel, P.; Jutzi, M.; Rivkin, A. S.; Stickle, A.; Barnouin, O.; Ernst, C.; Atchison, J.; Pravec, P.; Richardson, D. C.

    2016-02-01

    The Asteroid Impact & Deflection Assessment (AIDA) mission will be the first space experiment to demonstrate asteroid impact hazard mitigation by using a kinetic impactor to deflect an asteroid. AIDA is an international cooperation, consisting of two mission elements: the NASA Double Asteroid Redirection Test (DART) mission and the ESA Asteroid Impact Mission (AIM) rendezvous mission. The primary goals of AIDA are (i) to test our ability to perform a spacecraft impact on a potentially hazardous near-Earth asteroid and (ii) to measure and characterize the deflection caused by the impact. The AIDA target will be the binary near-Earth asteroid (65803) Didymos, with the deflection experiment to occur in late September, 2022. The DART impact on the secondary member of the binary at ~7 km/s is expected to alter the binary orbit period by about 4 minutes, assuming a simple transfer of momentum to the target, and this period change will be measured by Earth-based observatories. The AIM spacecraft will characterize the asteroid target and monitor results of the impact in situ at Didymos. The DART mission is a full-scale kinetic impact to deflect a 150 m diameter asteroid, with known impactor conditions and with target physical properties characterized by the AIM mission. Predictions for the momentum transfer efficiency of kinetic impacts are given for several possible target types of different porosities, using Housen and Holsapple (2011) crater scaling model for impact ejecta mass and velocity distributions. Results are compared to numerical simulation results using the Smoothed Particle Hydrodynamics code of Jutzi and Michel (2014) with good agreement. The model also predicts that the ejecta from the DART impact may make Didymos into an active asteroid, forming an ejecta coma that may be observable from Earth-based telescopes. The measurements from AIDA of the momentum transfer from the DART impact, the crater size and morphology, and the evolution of an ejecta coma will

  5. Deflection of uncooperative targets using laser ablation

    NASA Astrophysics Data System (ADS)

    Thiry, Nicolas; Vasile, Massimiliano

    2015-09-01

    Owing to their ability to move a target in space without requiring propellant, laser-based deflection methods have gained attention among the research community in the recent years. With laser ablation, the vaporized material is used to push the target itself allowing for a significant reduction in the mass requirement for a space mission. Specifically, this paper addresses two important issues which are thought to limit seriously the potential efficiency of a laser-deflection method: the impact of the tumbling motion of the target as well as the impact of the finite thickness of the material ablated in the case of a space debris. In this paper, we developed a steady-state analytical model based on energetic considerations in order to predict the efficiency range theoretically allowed by a laser deflection system in absence of the two aforementioned issues. A numerical model was then implemented to solve the transient heat equation in presence of vaporization and melting and account for the tumbling rate of the target. This model was also translated to the case where the target is a space debris by considering material properties of an aluminium 6061-T6 alloy and adapting at every time-step the size of the computational domain along with the recession speed of the interface in order to account for the finite thickness of the debris component. The comparison between the numerical results and the analytical predictions allow us to draw interesting conclusions regarding the momentum coupling achievable by a given laser deflection system both for asteroids and space debris in function of the flux, the rotation rate of the target and its material properties. In the last section of this paper, we show how a reasonably small spacecraft could deflect a 56m asteroid with a laser system requiring less than 5kW of input power.

  6. Asteroid Deflection: How, Where and When?

    NASA Astrophysics Data System (ADS)

    Fargion, D.

    2008-10-01

    To deflect impact-trajectory of massive and spinning km^3 asteroid by a few terrestrial radiuses one need a large momentum exchange. The dragging of huge spinning bodies in space by external engine seems difficult or impossible. Our solution is based on the landing of multi screw-rockets, powered by mini-nuclear engines, on the body, that dig a small fraction of the soil surface to use as an exhaust propeller, ejecting it vertically in phase among themselves. Such a mass ejection increases the momentum exchange, their number redundancy guarantees the stability of the system. The slow landing (below ≃ 40 cm s^{-1}) of each engine-unity at those very low gravity field, may be achieved by safe rolling and bouncing along the surface. The engine array tuned activity, overcomes the asteroid angular velocity. Coherent turning of the jet heads increases the deflection efficiency. A procession along its surface may compensate at best the asteroid spin. A small skin-mass (about 2×10^4 tons) may be ejected by mini-nuclear engines. Such prototypes may also build first safe galleries for humans on the Moon. Conclusive deflecting tests might be performed on remote asteroids. The incoming asteroid 99942 Apophis (just 2% of km^3) may be deflected safely a few Earth radiuses. Its encounter maybe not just a hazard but an opportunity, learning how to land, to dig, to build and also to nest safe human station inside. Asteroids amplified deflections by gravity swing may be driven into longest planetary journeys, beginning i.e. with the preliminary landing of future missions on Mars' moon-asteroid Phobos or Deimos.

  7. Analysis of HOM Properties of Superconducting Parallel-Bar Deflecting/Crabbing Cavities

    SciTech Connect

    S.U. De Silva, J.R. Delayen

    2011-07-01

    The superconducting parallel-bar cavity is currently being considered for a number of deflecting and crabbing applications due to improved properties and compact design geometries. The 499 MHz deflecting cavity proposed for the Jefferson Lab 12 GeV upgrade and the 400 MHz crab cavity for the proposed LHC luminosity upgrade are two of the major applications. For high current applications the higher order modes must be damped to acceptable levels to eliminate any beam instabilities. The frequencies and R/Q of the HOMs and mode separation are evaluated and compared for different parallel-bar cavity designs.

  8. System for deflection measurements of floating dry docks

    NASA Astrophysics Data System (ADS)

    Gorbachev, Alexey A.; Pantyushin, Anton V.; Serikova, Mariya G.; Korotaev, Valery V.; Timofeev, Aleksandr N.

    2015-05-01

    In this paper we introduce a system for deflection measurement of floating dry docks. The system contains two measurement channels observing opposite directions of the dock. It also includes set of reference marks, an industrial computer and a display. Each channel contains CMOS camera with long focal-length lens. Reference marks are implemented as IR LED arrays with 940 nm working wavelength for better performance within bad weather conditions (e.g. fog, rain, high humidity etc.). In the paper we demonstrate results of an analysis of different optical schemes for coupling the oppositely directed channels of the measurement unit and show that the scheme with two image sensors with separated lenses is an optimal option, because it allows usage of nonequidistant location of reference marks and demonstrates the least value of parasitic shift caused by rotations of the measuring unit. The developed system was tested both on specially-designed setup and in real infrastructure of a floating dry dock. The conducted tests proved that a measuring error of the system is smaller than +/- 1.5 mm within the measurement range of +/- 150 mm when deflection of 100 m dock is measured. Obtained results showed that the system demonstrates an ability to work in a harsh environment including poor weather conditions.

  9. Deflection of polarised radiation - Relative phase delay technique. [photon geodesic motion variations

    NASA Technical Reports Server (NTRS)

    Dennison, B.; Melnick, G.; Harwit, M.; Sato, T.; Stelzried, C. T.; Jauncey, D.

    1978-01-01

    The article discusses the geodesic motion of photons, considering particularly whether oppositely polarized photons fall at the same rate. It is assumed that orthogonally polarized photons would be equally deflected by the gravitational field of a nonrotating mass. Upon the introduction of rotation, the angular momentum of the deflecting source couples to the photon spin through gravitational field action. Thus there arise separate trajectories for orthogonal polarizations. Searching for changes in polarization in a deflected beam is accomplished by a relative phase delay technique. If the beam is split into orthogonal linear polarization, final polarization is elliptical. Experiments have been performed on searching for ellipticity developments in the linearly polarized carrier waves from Helios 1 and 2, and the results are presented.

  10. Self-deflecting plasmonic lattice solitons and surface modes in chirped plasmonic arrays.

    PubMed

    Li, Chunyan; Cui, Ran; Ye, Fangwei; Kartashov, Yaroslav V; Torner, Lluis; Chen, Xianfeng

    2015-03-15

    We show that chirped metal-dielectric waveguide arrays with focusing cubic nonlinearity can support plasmonic lattice solitons that undergo self-deflection in the transverse plane. Such lattice solitons are deeply subwavelength self-sustained excitations, although they cover several periods of the array. Upon propagation, the excitations accelerate in the transverse plane and follow trajectories curved in the direction in which the separation between neighboring metallic layers decreases, a phenomenon that yields considerable deflection angles. The deflection angle can be controlled by varying the array chirp. We also reveal the existence of surface modes at the boundary of truncated plasmonic chirped array that form even in the absence of nonlinearity. PMID:25768141

  11. Deflection of a flexural cantilever beam

    NASA Astrophysics Data System (ADS)

    Sherbourne, A. N.; Lu, F.

    The behavior of a flexural elastoplastic cantilever beam is investigated in which geometric nonlinearities are considered. The result of an elastica analysis by Frisch-Fay (1962) is extended to include postyield behavior. Although a closed-form solution is not possible, as in the elastic case, simple algebraic equations are derived involving only one unknown variable, which can also be expressed in the standard form of elliptic integrals if so desired. The results, in comparison with those of the small deflection analyses, indicate that large deflection analyses are necessary when the relative depth of the beam is very small over the length. The present exact solution can be used as a reference by those who resort to a finite element method for more complicated problems. It can also serve as a building block to other beam problems such as a simply supported beam or a beam with multiple loads.

  12. Deflection evaluation using time-resolved radiography

    SciTech Connect

    Fry, D.A.; Lucero, J.P.

    1990-01-01

    Time-resolved radiography is the creation of an x-ray image for which both the start-exposure and stop-exposure times are known with respect to the event under study. The combination of image and timing are used to derive information about the event. We have applied time-resolved radiography to evaluate motions of explosive-driven events. In the particular application discussed here, our intent is to measure maximum deflections of the components involved. Exposures are made during the time just before to just after the event of interest occurs. A smear or blur of motion out to its furthest extent is recorded on the image. Comparison of the dynamic images with static images allows deflection measurements to be made. 2 figs.

  13. AIDA: Asteroid Impact and Deflection Assessment

    NASA Astrophysics Data System (ADS)

    Michel, Patrick; Cheng, A.; Galvez, A.; Reed, C.; Carnelli, I.; Abell, P.; Ulamec, S.; Rivkin, A.; Biele, J.; Murdoch, N.

    2015-03-01

    AIDA (Asteroid Impact and Deflection Assessment) is a project of a joint mission demonstration of asteroid deflection and characterisation of the kinetic impact effects. It involves the Johns Hopkins Applied Physics Laboratory (with support from members of NASA centers including Goddard Space Flight Center, Johnson Space Center, and the Jet Propulsion Laboratory), and the European Space Agency (with support from members of the french CNRS/Cte dAzur Observatory and the german DLR). This assessment will be done using a binary asteroid target. AIDA consists of two independent but mutually supporting mission concepts, one of which is the asteroid kinetic impactor and the other is the characterisation spacecraft. The objective and status of the project will be presented.

  14. Dark matter prospects in deflected mirage mediation

    NASA Astrophysics Data System (ADS)

    Holmes, Michael; Nelson, Brent D.

    2009-07-01

    The recently introduced deflected mirage mediation (DMM) model is a string-motivated paradigm in which all three of the major supersymmetry-breaking transmission mechanisms are operative. We begin a systematic exploration of the parameter space of this rich model context, paying special attention to the pattern of gaugino masses which arise. In this work we focus on the dark matter phenomenology of the DMM model as such signals are the least influenced by the model-dependent scalar masses. We find that a large portion of the parameter space in which the three mediation mechanisms have a similar effective mass scale of 1 TeV or less will be probed by future direct and indirect detection experiments. Distinguishing deflected mirage mediation from the mirage model without gauge mediation will prove difficult without collider input, though we indicate how gamma ray signals may provide an opportunity for distinguishing between the two paradigms.

  15. Polyhedron tracking and gravity tractor asteroid deflection

    NASA Astrophysics Data System (ADS)

    Ummen, N.; Lappas, V.

    2014-11-01

    In the wake of the Chelyabinsk airburst, the defense against hazardous asteroids is becoming a topic of high interest. This work improves the gravity tractor asteroid deflection approach by tracking realistic small body shapes with tilted ion engines. An algorithm for polyhedron tracking was evaluated in a fictitious impact scenario. The simulations suggest a capability increase up to 38.2% with such improved tilting strategies. The long- and short-term effects within polyhedron tracking are illustrated. In particular, the orbital reorientation effect is influential when realistic asteroid shapes and rotations are accounted for. Also analyzed is the subject of altitude profiles, a way to tailor the gravity tractor performance, and to achieve a steering ability within the B-plane. A novel analytical solution for the classic gravity tractor is derived. It removes the simulation need for classic tractor designs to obtain comparable two body model Δv figures. This paper corroborates that the asteroid shape can be exploited for maximum performance. Even a single engine tilt adjustment at the beginning of deflection operations yields more deflection than a fixed preset tilt.

  16. Small Deflection Energy Analyzer for Energy and Angular Distributions

    NASA Technical Reports Server (NTRS)

    Herrero, Federico A.

    2009-01-01

    The development of the Small Deflection Energy Analyzer (SDEA) charged-particle spectrometer for energy and angle distributions responds to a longstanding need to measure the wind velocity vector in Earth s thermosphere, and to obtain the ion-drift vector in the ionosphere. The air and ions above 120 km are endowed with bulk velocities and temperatures just like air near the ground, but with separate spatial and temporal variations. It is important to understand these not only for study of the physics and chemistry of the Sun-Earth connection, but also for spacecraft orbit predictions, and communications through the ionosphere. The SDEA consists of a pair of parallel conducting plates separated by a small distance, with an entrance slit on one end, and an exit slit on the other. A voltage applied to these plates develops an electric field between the plates, and this field deflects ions passing through it. If an ion has too little energy, it will strike one of the plates. If it has too much, it will strike the back wall. An ion with the amount of energy being searched for will have its trajectory bent just enough to exit the back slit. The SDEA units are compact, rectangular, and operate with low voltages. The units can be built up into small arrays. These arrays could be used either to widen the field of view or to sharpen an existing one. This approach can also be used to obtain angular distributions in two planes simultaneously, thus cutting down the ion source power requirements in half. This geometry has enabled a new mass-spectrometer concept that can provide miniaturized mass spectrometers for use in industrial plants, air-pollution monitoring, and noxious-gas detection.

  17. Designs of Superconducting Parallel-Bar Deflecting Cavities for Deflecting/Crabbing Applications

    SciTech Connect

    Delayen, J. R.; De Silva, S. U.

    2011-07-01

    The superconducting parallel-bar cavity is a deflecting/crabbing cavity with attractive properties, compared to other conventional designs, that is currently being considered for a number of applications. The new parallel-bar design with curved loading elements and circular or elliptical outer conductors have improved properties compared to the designs with rectangular outer conductors. We present the designs proposed as deflecting cavities for the Jefferson Lab 12 GeV upgrade and for Project-X and as crabbing cavities for the proposed LHC luminosity upgrade and electron-ion collider at Jefferson Lab.

  18. Deflection of Propeller Blades While Running

    NASA Technical Reports Server (NTRS)

    Katzmayr, R

    1922-01-01

    The forces acting on the blades of a propeller proceed from the mass of the propeller and the resistance of the surrounding medium. The magnitude, direction and point of application of the resultant to the propeller blade is of prime importance for the strength calculation. Since it was obviously impracticable to bring any kind of testing device near the revolving propeller, not so much on account of the element of danger as on account of the resulting considerable disturbance of the air flow, the deflection in both cases was photographically recorded and subsequently measured at leisure.

  19. Dark matter signals in deflected mirage mediation

    SciTech Connect

    Holmes, Michael

    2010-02-10

    We investigate the parameter space of a specific class of model within the deflected mirage mediation (DMM) scenario. We look at neutralino properties and compute the thermal relic density as well as interaction rates with xenon direct detection experiments. We find that there are portions of the parameter space which are in line with the current WMAP constraints. Further we find that none of the investigated parameter space is in conflict with current bounds from the Xenon10 experiment and that future large-scale liquid xenon experiments will probe a large portion of the model space.

  20. Electroweak naturalness and deflected mirage mediation

    NASA Astrophysics Data System (ADS)

    Barger, Vernon; Everett, Lisa L.; Garon, Todd S.

    2016-04-01

    We investigate the question of electroweak naturalness within the deflected mirage mediation (DMM) framework for supersymmetry breaking in the minimal supersymmetric standard model. The class of DMM models considered are nine-parameter theories that fall within the general classification of the 19-parameter phenomenological minimal supersymmetric standard model. Our results show that these DMM models have regions of parameter space with very low electroweak fine-tuning, at levels comparable to the phenomenological minimal supersymmetric standard model. These parameter regions should be probed extensively in the current LHC run.

  1. DEFLECTION MEASUREMENTS OF 25 mm ALUMINUM COLLARS

    SciTech Connect

    Peters, C.

    1984-10-01

    This report is a summary of mechanical load-deflection tests performed on prototype collars. The individual collar plates were N.C. machined from 0.125 inch thick 7075-T6 aluminum alloy plate. Inside corners were finished by EDM and outside corners and keyways were finished with an end milling operation. The last step was done with all the individual collar plates (98 pieces) assembled on pins to form the cross section shown in Fig. 1. Figure 1 also shows some of the basic collar dimensions.

  2. Determination of peak deflections from human surrogates using chestbands in side impact tests.

    PubMed

    Yoganandan, Narayan; Humm, John R; Pintar, Frank A; Maiman, Dennis J

    2013-08-01

    To understand the biomechanics of the human body in motor vehicle environments, physical models including anthropomorphic test devices (ATD) and biological models (postmortem human surrogates) are used, and sled tests are conducted. Deflection is often used as a biomechanical variable to characterize the effects of impact loading and derive injury criteria. The objective of the present study was to evaluate different techniques and recommend a methodology to determine the peak thorax and abdominal deflections from temporal contours using chestbands in oblique lateral impacts. The side impact ATD WorldSID representing human surrogates was positioned on a seat. The seat was rigidly fixed to the platform of an acceleration sled. The oblique load-wall fixed to the sled consisted of separate and adjustable plates to contact the shoulder, thorax, abdomen, and pelvis. Two 59-gage chestbands were wrapped on the thorax and abdomen. Tests were conducted at low, medium, and high velocities (3.4, 6.7, and 7.5m/s) and three methods, termed the spine-sternum, bilateral, and spine-box, were used to determine the global peak deflection and its angulation. Results indicated that all three methods produced very similar angulations, for all velocity tests, and at both thorax and abdominal regions. However, maximum deflections were the lowest in the spine-sternum, followed by bilateral and spine-box methods, with one exception. Based on the development of deflection contours, locations used in the definitions of the origin, and accuracy in identifying critical locations/points in time-varying contours, results of the present study indicate that the bilateral method is the optimum procedure to determine the oblique peak deflection vector in biomechanical tests. PMID:23357337

  3. CdSe-sensitized branched CdS hierarchical nanostructures for efficient photoelectrochemical solar hydrogen generation.

    PubMed

    Han, Zonghu; Wang, Meng; Chen, Xiangyan; Shen, Shaohua

    2016-04-28

    A two-step hydrothermal process was used to synthesize branched CdS hierarchical nanostructures, which were then sensitized by CdSe via a chemical bath deposition method. CdS nanorods grew on the surface of the existing CdS nanorods to form hierarchical assemblies. After the chemical bath deposition process, core-shell structures of branched CdS nanorods covered by a uniform CdSe overlayer were formed. The branched hierarchical nanostructure improved the optical absorption by increasing the optical path via additional light trapping, as well as increasing the contact area between the electrode and electrolyte for more reactive sites, contributing to the higher photoelectrochemical performance than that obtained for the rod-like nanostructures. After CdSe sensitization, with the optical absorption greatly extended to longer wavelengths and the photoexcited charge carriers efficiently separated at the type II CdS/CdSe interface, the branched CdS/CdSe hierarchical nanostructures showed considerably increased photoelectrochemical performance compared with the CdS/CdSe nanorods, with a photoconversion efficiency for solar hydrogen generation of 2.7%. PMID:27058590

  4. Light-stimulated carrier dynamics of CuInS2/CdS heterotetrapod nanocrystals.

    PubMed

    Sakamoto, Masanori; Inoue, Koki; Okano, Makoto; Saruyama, Masaki; Kim, Sungwon; So, Yeong-Gi; Kimoto, Koji; Kanemitsu, Yoshihiko; Teranishi, Toshiharu

    2016-05-14

    We synthesized a heterotetrapod composed of a chalcopyrite(ch)-CuInS2 core and wurtzite(w)-CdS arms and elucidated its optical properties and light-stimulated carrier dynamics using fs-laser flash photolysis. The CuInS2/CdS heterotetrapod possessed quasi-type II band alignment, which caused much longer-lived charge separation than that in the isolated CuInS2 nanocrystal. PMID:27118533

  5. Theory of using magnetic deflections to combine charged particle beams.

    SciTech Connect

    Doyle, Barney Lee; Steckbeck, Mackenzie K.

    2014-09-01

    Several radiation effects projects in the Ion Beam Lab (IBL) have recently required two disparate charged particle beams to simultaneously strike a single sample through a single port of the target chamber. Because these beams have vastly different mass- energy products (MEP), the low MEP beam requires a large angle of deflection toward the sample by a bending electromagnet. A second electromagnet located further upstream provides a means to compensate for the small angle deflection experienced by the high MEP beam during its path through the bending magnet. This paper derives the equations used to select the magnetic fields required by these two magnets to achieve uniting both beams at the target sample. A simple result was obtained when the separation of the two magnets was equivalent to the distance from the bending magnet to the sample, and the equations is given by: , 1 2 c s c s r B B r where and are the magnetic fields in the steering and bending magnet and is s B c B c s r r the ratio of the radii of the bending magnet to that of the steering magnet. This result is not dependent upon the parameters of the high MEP beam, i.e. energy, mass, charge state. Therefore, once the field of the bending magnet is set for the low MEP beam, and the field in the steering magnet is set as indicted in the equation, the trajectory path of any high MEP beam will be directed into the sample. (page intentionally left blank)

  6. Mining the CDS Collection: A Learning Experience

    NASA Astrophysics Data System (ADS)

    Ortiz, Patricio F.; Ochsenbein, François

    The experiences gained as a result of the CDS/ESO Datamining project are described in this paper as well as a brief outline of the tools developed (described in Ortiz et al. 1998 and Ortiz, 2000). Important issues about datamining and the exchange of information in the context of the Virtual Observatory are described and discussed, emphasizing the need of consistent meta-information for the exchange of data amongst servers and institutions.

  7. Materials separation by dielectrophoresis

    NASA Technical Reports Server (NTRS)

    Sagar, A. D.; Rose, R. M.

    1988-01-01

    The feasibility of vacuum dielectrophoresis as a method for particulate materials separation in a microgravity environment was investigated. Particle separations were performed in a specially constructed miniature drop-tower with a residence time of about 0.3 sec. Particle motion in such a system is independent of size and based only on density and dielectric constant, for a given electric field. The observed separations and deflections exceeded the theoretical predictions, probably due to multiparticle effects. In any case, this approach should work well in microgravity for many classes of materials, with relatively simple apparatus and low weight and power requirements.

  8. Flow visualization and interpretation of visualization data for deflected thrust V/STOL nozzles

    NASA Technical Reports Server (NTRS)

    Kao, H. C.; Burstadt, P. L.; Johns, A. L.

    1984-01-01

    Flow visualization studies were made for four deflected thrust nozzle models at subsonic speeds. Based on topological rules and the assumption that observed streaks constitute continuous vector fields, available visualization pictures are interpreted and flow patterns on interior surfaces of the nozzles are synthesized. In particular, three dimensional flow structure and separations are discussed. From the synthesized patterns, the overall features of the flow field in a given nozzle can be approximately perceived.

  9. Beam-beam deflection and signature curves for elliptic beams

    SciTech Connect

    Ziemann, V.

    1990-10-22

    In this note we will present closed expressions for the beam-beam deflection angle for arbitrary elliptic beams including tilt. From these expressions signature curves, i.e., systematic deviations from the round beam deflection curve due to ellipticity or tilt are derived. In the course of the presentation we will prove that it is generally impossible to infer individual beam sizes from beam-beam deflection scans. 3 refs., 2 figs.

  10. In situ self-transformation synthesis of g-C3N4-modified CdS heterostructure with enhanced photocatalytic activity

    NASA Astrophysics Data System (ADS)

    Yu, Huogen; Chen, Fengyun; Chen, Feng; Wang, Xuefei

    2015-12-01

    The fabrication of heterojunction photocatalysts with uniform dispersion and strongly coupling interface is one of the main strategies to improve the photocatalytic activity of semiconductor materials. In this study, the heterostructured g-C3N4/CdS photocatalyst with above features was synthesized via a facile in situ high-temperature self-transformation method by using melamine-CdS composites as the precursor. The results showed that g-C3N4 nanoparticles (5-30 nm) are homogeneously grafted on the CdS surface with closely contacted interfaces, resulting in a greatly improved photocatalytic hydrogen-production performance. When the amount of g-C3N4 was 1 wt%, the resultant g-C3N4/CdS showed the highest hydrogen evolution rate (5303 μmol h-1 g-1), which is significantly higher than the pure CdS by a factor of 2.5 times. Considering the obviously enhanced performance of CdS by loading a very limited g-C3N4 (0.1-5 wt%), a possible photocatalytic mechanism was proposed, namely, the g-C3N4 works as an effective hole-transfer cocatalyst to promote the rapid transfer of photogenerated holes from the CdS surface, causing the effective separation of photogenerated charges in CdS. Our present work can provide some interesting idea for the reasonable design and preparation of other highly efficient heterojunction photocatalysts.

  11. The genomic CDS sandbox: An assessment among domain experts.

    PubMed

    Aziz, Ayesha; Kawamoto, Kensaku; Eilbeck, Karen; Williams, Marc S; Freimuth, Robert R; Hoffman, Mark A; Rasmussen, Luke V; Overby, Casey L; Shirts, Brian H; Hoffman, James M; Welch, Brandon M

    2016-04-01

    Genomics is a promising tool that is becoming more widely available to improve the care and treatment of individuals. While there is much assertion, genomics will most certainly require the use of clinical decision support (CDS) to be fully realized in the routine clinical setting. The National Human Genome Research Institute (NHGRI) of the National Institutes of Health recently convened an in-person, multi-day meeting on this topic. It was widely recognized that there is a need to promote the innovation and development of resources for genomic CDS such as a CDS sandbox. The purpose of this study was to evaluate a proposed approach for such a genomic CDS sandbox among domain experts and potential users. Survey results indicate a significant interest and desire for a genomic CDS sandbox environment among domain experts. These results will be used to guide the development of a genomic CDS sandbox. PMID:26778834

  12. The Genomic CDS Sandbox: An Assessment Among Domain Experts

    PubMed Central

    Aziz, Ayesha; Kawamoto, Kensaku; Eilbeck, Karen; Williams, Marc S.; Freimuth, Robert R.; Hoffman, Mark A.; Rasmussen, Luke V.; Overby, Casey L.; Shirts, Brian H.; Hoffman, James M.; Welch, Brandon M.

    2016-01-01

    Genomics is a promising tool that is becoming more widely available to improve the care and treatment of individuals. While there is much assertion, genomics will most certainly require the use of clinical decision support (CDS) to be fully realized in the routine clinical setting. The National Human Genome Research Institute (NHGRI) of the National Institutes of Health recently convened an in-person, multi-day meeting on this topic. It was widely recognized that there is a need to promote the innovation and development of resources for genomic CDS such as a CDS sandbox. The purpose of this study was to evaluate a proposed approach for such a genomic CDS sandbox among domain experts and potential users. Survey results indicate a significant interest and desire for a genomic CDS sandbox environment among domain experts. These results will be used to guide the development of a genomic CDS sandbox. PMID:26778834

  13. Deflecting light into resonant cavities for spectroscopy

    DOEpatents

    Zare, Richard N.; Martin, Juergen; Paldus, Barbara A.

    1998-01-01

    Light is coupled into a cavity ring down spectroscopy (CRDS) resonant cavity using an acousto-optic modulator. The AOM allows in-coupling efficiencies in excess of 40%, which is two to three orders of magnitude higher than in conventional systems using a cavity mirror for in-coupling. The AOM shutoff time is shorter than the roundtrip time of the cavity. The higher light intensities lead to a reduction in shot noise, and allow the use of relatively insensitive but fast-responding detectors such as photovoltaic detectors. Other deflection devices such as electro-optic modulators or elements used in conventional Q-switching may be used instead of the AOM. The method is particularly useful in the mid-infrared, far-infrared, and ultraviolet wavelength ranges, for which moderately reflecting input mirrors are not widely available.

  14. Deflecting light into resonant cavities for spectroscopy

    DOEpatents

    Zare, R.N.; Martin, J.; Paldus, B.A.

    1998-09-29

    Light is coupled into a cavity ring down spectroscopy (CRDS) resonant cavity using an acousto-optic modulator. The AOM allows in-coupling efficiencies in excess of 40%, which is two to three orders of magnitude higher than in conventional systems using a cavity mirror for in-coupling. The AOM shutoff time is shorter than the roundtrip time of the cavity. The higher light intensities lead to a reduction in shot noise, and allow the use of relatively insensitive but fast-responding detectors such as photovoltaic detectors. Other deflection devices such as electro-optic modulators or elements used in conventional Q-switching may be used instead of the AOM. The method is particularly useful in the mid-infrared, far-infrared, and ultraviolet wavelength ranges, for which moderately reflecting input mirrors are not widely available. 5 figs.

  15. Trace Explosive Detection using Photothermal Deflection Spectroscopy

    SciTech Connect

    Krause, Adam R; Van Neste, Charles W; Senesac, Larry R; Thundat, Thomas George; Finot, Eric

    2008-01-01

    Satisfying the conditions of high sensitivity and high selectivity using portable sensors that are also reversible is a challenge. Miniature sensors such as microcantilevers offer high sensitivity but suffer from poor selectivity due to the lack of sufficiently selective receptors. Although many of the mass deployable spectroscopic techniques provide high selectivity, they do not have high sensitivity. Here, we show that this challenge can be overcome by combining photothermal spectroscopy on a bimaterial microcantilever with the mass induced change in the cantilever's resonance frequency. Detection using adsorption-induced resonant frequency shift together with photothermal deflection spectroscopy shows extremely high selectivity with a subnanogram limit of detection for vapor phase adsorbed explosives, such as pentaerythritol tetranitrate (PETN), cyclotrimethylene trinitramine (RDX), and trinitrotoluene (TNT).

  16. Photothermal deflection spectroscopy investigations of uranium electrochemistry

    SciTech Connect

    Rudnicki, J.D.; Russo, R.E.

    1993-12-31

    Photothermal Deflection Spectroscopy (PDS) has been successfully applied successfully applied to the study of uranium oxide electrochemistry. A brief description of PDS and preliminary results that demonstrate the technique are presented. Concentration gradients formed at the electrode surface are measured by this technique. The gradients give insight into the reaction mechanisms. There is some evidence of the initiation of non-electrochemical dissolution of the uranium oxide. Optical absorption by the uranium oxide is measured by PDS and the first results indicate that the absorption of the surface does not change during electrochemical experiments. This result is contrary to literature measurements of bulk samples that indicate that the optical absorption should be strongly changing.

  17. Igniter adapter-to-igniter chamber deflection test

    NASA Technical Reports Server (NTRS)

    Cook, M.

    1990-01-01

    Testing was performed to determine the maximum RSRM igniter adapter-to-igniter chamber joint deflection at the crown of the inner joint primary seal. The deflection data was gathered to support igniter inner joint gasket resiliency predictions which led to launch commit criteria temperature determinations. The proximity (deflection) gage holes for the first test (Test No. 1) were incorrectly located; therefore, the test was declared a non-test. Prior to Test No. 2, test article configuration was modified with the correct proximity gage locations. Deflection data were successfully acquired during Test No. 2. However, the proximity gage deflection measurements were adversely affected by temperature increases. Deflections measured after the temperature rise at the proximity gages were considered unreliable. An analysis was performed to predict the maximum deflections based on the reliable data measured before the detectable temperature rise. Deflections to the primary seal crown location were adjusted to correspond to the time of maximum expected operating pressure (2,159 psi) to account for proximity gage bias, and to account for maximum attach and special bolt relaxation. The maximum joint deflection for the igniter inner joint at the crown of the primary seal, accounting for all significant correction factors, was 0.0031 in. (3.1 mil). Since the predicted (0.003 in.) and tested maximum deflection values were sufficiently close, the launch commit criteria was not changed as a result of this test. Data from this test should be used to determine if the igniter inner joint gasket seals are capable of maintaining sealing capability at a joint displacement of (1.4) x (0.0031 in.) = 0.00434 inches. Additional testing should be performed to increase the database on igniter deflections and address launch commit criteria temperatures.

  18. CdS Nanowires Decorated with Ultrathin MoS2 Nanosheets as an Efficient Photocatalyst for Hydrogen Evolution.

    PubMed

    He, Jie; Chen, Lang; Wang, Fu; Liu, Ying; Chen, Peng; Au, Chak-Tong; Yin, Shuang-Feng

    2016-03-21

    CdS nanowires decorated with ultrathin MoS2 nanosheets were synthesized for the first time by ultrasonic exfoliation by using dimethylformamide as the dispersing agent. An excellent hydrogen evolution rate of 1914 μmol h(-1) (20 mg catalyst) under visible-light irradiation (λ≥400 nm, ≈154 mW cm(-1) ) and an apparent quantum yield of 46.9 % at λ=420 nm were achieved over the MoS2 /CdS composite. The presence of ultrathin MoS2 nanosheets (rich in active edge sites) on the CdS surface promotes the separation of photogenerated charge carriers and facilitates the surface processes of photocatalytic hydrogen evolution. PMID:26879708

  19. Photodetectors of slit and sandwich types based on CdS and CdS1-xSex films obtained using MOCVD method from dithiocarbamates

    NASA Astrophysics Data System (ADS)

    Zavyalova, Ludmila V.; Svechnikov, Sergey V.; Tchoni, Vladimir G.

    1997-04-01

    Here we report the results of working out an original, simple in control and not requiring expensive equipment MOCVD-method for depositing films of semiconductor compounds A2B6. Dithiocarbamates (DTC) are used as starting materials. The compounds are stable, easily synthesized, cheap and low toxic. Atoms of metal and sulfur in the DTC are strongly bonded. The DTC could be easily dissolved in various organic solvents. The experimental unit for film deposition comprises a spraying apparatus, a substrate heater, and a quartz cylinder for separation of a reaction zone from ambience. The process of film deposition is carried out in air conditions. Films of CdS, bright-yellow, transparent, having mirror smooth surface at thickness less than 2 mkm and rough surface at thickness 8-12 mkm, were deposited by spraying cadmium dithiocarbamate, that is DTC with radical C2H5, solution in pyridine on substrates heated to 240-280 degrees C. Deposition rate was 60-90 nm/min. Films obtained were of hexagonal modification, polycrystalline, textured, with low, at the level of centipercents content of oxygen and carbon. Slit type photodetectors based on CdS and CdS1-xSex of 1.0 mkm thickness have dark conductivity (sigma) d equals 10-9 divided by 10-8 Ohm-1cm-1 and photoconductivity (sigma) ph equals 10-2 divided by 10-1 Ohm-1cm-1 at 200 lux. Industrially suitable technology for production of photopotentiometer on the base of these films was developed. Sandwich-type photodetectors In2S3 - CdS: Cu, Cl - In with 8-12 mkm thickness have the same value of photoconductivity and the light-to-dark ratio is 106 divided by 107. Based on sandwich-type photodetectors, a hybrid structure of pyroelectric-photodetector as a resonant-type coordinate-sensitive detector was developed.

  20. Study on dynamics of photoexcited charge injection and trapping in CdS quantum dots sensitized TiO2 nanowire array film electrodes

    NASA Astrophysics Data System (ADS)

    Pang, Shan; Cheng, Ke; Yuan, Zhanqiang; Xu, Suyun; Cheng, Gang; Du, Zuliang

    2014-05-01

    The photoexcited electrons transfer dynamics of the CdS quantum dots (QDs) deposited in TiO2 nanowire array films are studied using surface photovoltage (SPV) and transient photovoltage (TPV) techniques. By comparing the SPV results with different thicknesses of QDs layers, we can separate the dynamic characteristics of photoexcited electrons injection and trapping. It is found that the TPV signals of photoexcited electrons trapped in the CdS QDs occur at timescales of about 2 × 10-8 s, which is faster than that of the photoexcited electrons injected from CdS into TiO2. More than 90 nm of the thickness of the CdS QDs layer will seriously affect the photoexcited electrons transfer and injection.

  1. Study on dynamics of photoexcited charge injection and trapping in CdS quantum dots sensitized TiO{sub 2} nanowire array film electrodes

    SciTech Connect

    Pang, Shan; Cheng, Ke; Yuan, Zhanqiang; Xu, Suyun; Cheng, Gang; Du, Zuliang

    2014-05-19

    The photoexcited electrons transfer dynamics of the CdS quantum dots (QDs) deposited in TiO{sub 2} nanowire array films are studied using surface photovoltage (SPV) and transient photovoltage (TPV) techniques. By comparing the SPV results with different thicknesses of QDs layers, we can separate the dynamic characteristics of photoexcited electrons injection and trapping. It is found that the TPV signals of photoexcited electrons trapped in the CdS QDs occur at timescales of about 2 × 10{sup −8} s, which is faster than that of the photoexcited electrons injected from CdS into TiO{sub 2}. More than 90 nm of the thickness of the CdS QDs layer will seriously affect the photoexcited electrons transfer and injection.

  2. Teach Deflection Concepts with Hacksaw Blades and Rubber Bands

    ERIC Educational Resources Information Center

    Roman, Harry T.

    2013-01-01

    Technology and engineering educators can use a simple hacksaw blade to help students learn about deflection, as that which occurs in a beam. Here the beam is fixed at one end and allowed to deflect in a manner that is easy to see and measure--the hacksaw blade represents a cantilever, an overhanging structure. This simple and very inexpensive…

  3. Optical absorption components of light-modulated absorption spectrum of CdS

    NASA Technical Reports Server (NTRS)

    Conway, E. J.; Long, E. R.

    1975-01-01

    The amplitude and decay coefficient of light-induced modulation of absorption (LIMA) was measured as a function of wavelength from 535 to 850 nm for single-crystal CdS. The decay coefficient exhibited a discontinuous resonance at 710 nm which was due to the overlap and cancellation of two opposing absorption changes. A method was developed to separate these opposing absorption changes using the measured decay coefficients. The discrete-level-to-band energy for one absorption change was found to be 1.64 eV. An improved model was developed which contains two associated levels in the band gap separated by 0.32 eV.

  4. Applicability of moire deflection tomography for diagnosing arc plasmas

    SciTech Connect

    Chen Yunyun; Song Yang; He Anzhi; Li Zhenhua

    2009-01-20

    The argon arc plasma whose central temperature, 1.90x10{sup 4} K, is used as a practical example for an experiment to research the applicability of moire deflection tomography in arc plasma flow-field diagnosis. The experimental result indicates that moire deflection of the measured argon arc plasma is very small, even smaller than that of a common flame with the maximal temperature of nearly 1.80x10{sup 3} K. The refractive-index gradient in moire deflection tomography mainly contributes to the temperature gradient in essence when the probe wavelength and pressure are certain in plasma diagnosis. The applicable temperature ranges of moire deflection tomography in the argon arc plasma diagnosis are given with the probe wavelength 532 nm at 1 atm in certain measuring error requirements. In a word, the applicable temperature range of moire deflection tomography for arc plasma diagnosis is intimately related to the probe wavelength and the practical measuring requirements.

  5. A computational study of asymmetric glottal jet deflection during phonation.

    PubMed

    Zheng, X; Mittal, R; Bielamowicz, S

    2011-04-01

    Two-dimensional numerical simulations are used to explore the mechanism for asymmetric deflection of the glottal jet during phonation. The model employs the full Navier-Stokes equations for the flow but a simple laryngeal geometry and vocal-fold motion. The study focuses on the effect of Reynolds number and glottal opening angle with a particular emphasis on examining the importance of the so-called "Coanda effect" in jet deflection. The study indicates that the glottal opening angle has no substantial effect on glottal jet deflection. Deflection in the glottal jet is always preceded by large-scale asymmetry in the downstream portion of the glottal jet. A detailed analysis of the velocity and vorticity fields shows that these downstream asymmetric vortex structures induce a flow at the glottal exit which is the primary driver for glottal jet deflection. PMID:21476669

  6. Nonlinear large-deflection analysis of orthodontic wires.

    PubMed

    Hayashi, Kazuo; Araki, Yoshima; Mizoguchi, Itaru

    2004-02-01

    The purposes of this study were (1) to measure the nonlinear force-deflection behavior of selected orthodontic wires using a conventional tensile test, (2) to extend a mathematical model for simulating the force system produced by orthodontic wires based on the small-deflection linear theory to the large-deflection nonlinear theory, and (3) to examine the effects of the cross-section and mechanical properties of orthodontic wires on nonlinear characteristics. A method for extending a mathematical model for simulating the force system produced by orthodontic wires based on the small-deflection linear theory to the large-deflection nonlinear theory was established, and this can provide a clear view of the true nature of orthodontic wires. Furthermore, our results demonstrated that the nonlinear properties of orthodontic wires were affected more by the cross-sectional shape than by mechanical properties. PMID:15038499

  7. A computational study of asymmetric glottal jet deflection during phonation

    PubMed Central

    Zheng, X.; Mittal, R.; Bielamowicz, S.

    2011-01-01

    Two-dimensional numerical simulations are used to explore the mechanism for asymmetric deflection of the glottal jet during phonation. The model employs the full Navier–Stokes equations for the flow but a simple laryngeal geometry and vocal-fold motion. The study focuses on the effect of Reynolds number and glottal opening angle with a particular emphasis on examining the importance of the so-called “Coanda effect” in jet deflection. The study indicates that the glottal opening angle has no substantial effect on glottal jet deflection. Deflection in the glottal jet is always preceded by large-scale asymmetry in the downstream portion of the glottal jet. A detailed analysis of the velocity and vorticity fields shows that these downstream asymmetric vortex structures induce a flow at the glottal exit which is the primary driver for glottal jet deflection. PMID:21476669

  8. Intelligent deflection routing in buffer-less networks.

    PubMed

    Haeri, Soroush; Trajković, Ljiljana

    2015-02-01

    Deflection routing is employed to ameliorate packet loss caused by contention in buffer-less architectures such as optical burst-switched networks. The main goal of deflection routing is to successfully deflect a packet based only on a limited knowledge that network nodes possess about their environment. In this paper, we present a framework that introduces intelligence to deflection routing (iDef). iDef decouples the design of the signaling infrastructure from the underlying learning algorithm. It consists of a signaling and a decision-making module. Signaling module implements a feedback management protocol while the decision-making module implements a reinforcement learning algorithm. We also propose several learning-based deflection routing protocols, implement them in iDef using the ns-3 network simulator, and compare their performance. PMID:25532199

  9. Load Deflection Characteristics of Nickel Titanium Initial Archwires

    PubMed Central

    Aghili, Hossein; Yasssaei, Sogra; Ahmadabadi, Mahmoud Nilli

    2015-01-01

    Objectives: The aim of this study was to assess and compare the characteristics of commonly used initial archwires by their load deflection graphs. Materials and Methods: This study tested three wire designs namely copper nickel titanium (CNT), nickel titanium (NiTi), and multi-strand NiTi (MSNT) archwires engaged in passive self-ligating (PSL) brackets, active self-ligating (ASL) brackets or conventional brackets. To evaluate the mechanical characteristics of the specimens, a three-point bending test was performed. The testing machine vertically applied force on the midpoint of the wire between the central incisor and canine teeth to obtain 2 and 4mm of deflection. The force level at maximum deflection and characteristics of plateau (the average plateau load and the plateau length) were recorded. Two-way ANOVA and Tukey’s test were used at P <0.05 level of significance. Results: Force level at maximum deflection and plateau length were significantly affected by the amount of deflection. The type of archwires and brackets had significant effects on force level at maximum deflection, and plateau length. However, the bracket type had no significant effect on the average plateau force. Conclusion: With any type of brackets in deflections of 2 and 4mm, MSNT wire exerted the lowest while NiTi wire exerted the highest force level at maximum deflection and plateau phase. The force level at maximum deflection and the plateau length increased with raising the amount of primary deflection; however the average plateau force did not change significantly. PMID:27148381

  10. Mission Designs for Demonstrating Gravity Tractor Asteroid Deflection

    NASA Astrophysics Data System (ADS)

    Busch, M.; Faber, N.; Eggl, S.; Morrison, D.; Clark, A.; Frost, C.; Jaroux, B. A.; Khetawat, V.

    2015-12-01

    Gravity tractor asteroid deflection relies on the gravitational attraction between the target and a nearby spacecraft; using low-thrust propulsion to change the target's trajectory slowly but continuously. Our team, based at the NASA Ames Mission Design Center, prepared designs for a Gravity Tractor Demonstration Mission (GTDM) for the European Commission's NEOShield initiative. We found five asteroids with well-known orbits and opportunities for efficient stand-alone demonstrations in the 2020s. We selected one object, 2000 FJ10, for a detailed design analysis. Our GTDM design has a 4 kW solar-electric propulsion system and launch mass of 1150 kg. For a nominal asteroid mass of 3 x 109 kg and diameter 150 m, and a hovering altitude 125 m above the asteroid's surface, GTDM would change FJ10's semi-major axis by 10 km over 2 years. To measure the deflection clearly and to permit safe hovering by the spacecraft, several months of survey and characterization are required prior to the active tractoring phase of the mission. Accurate tracking is also required after the tractoring phase, to ensure that the asteroid has indeed been deflected as intended. The GTDM design includes both spacecraft and Earth-based observations of FJ10 to verify the deflection. The estimated cost of GTDM is $280 million. Trajectory analysis for GTDM confirmed that the outcome of a deflection of any asteroid depends on when that deflection is performed. Compared to kinetic impactor deflection, the gradual deflection from a gravity tractor produces comparable results for a given total momentum transfer. However, a gravity tractor can have greater flexibility in the direction in which the target asteroid can be deflected. Asteroid deflection scenarios must be modeled carefully on a case-to-case basis. We will review implications of the results of the GTDM study to other proposed gravity tractor demonstrations, such as that included in NASA's Asteroid Redirect Mission.

  11. Unesco Integrated Documentation Network; Computerized Documentation System (CDS).

    ERIC Educational Resources Information Center

    United Nations Educational, Scientific, and Cultural Organization, Paris (France). Dept. of Documentation, Libraries, and Archives.

    Intended for use by the Computerized Documentation System (CDS), the Unesco version of ISIS (Integrated Set of Information Systems)--originally developed by the International Labour Organization--was developed in 1975 and named CDS/ISIS. This system has a comprehensive collection of programs for input, management, and output, running in batch or…

  12. Method for isotope separation by photodeflection

    DOEpatents

    Bernhardt, Anthony F.

    1977-01-01

    In the method of separating isotopes wherein a desired isotope species is selectively deflected out of a beam of mixed isotopes by irradiating the beam with a directed beam of light of narrowly defined frequency which is selectively absorbed by the desired species, the improvement comprising irradiating the deflected beam with light from other light sources whose frequencies are selected to cause the depopulation of any metastable excited states.

  13. Thermal Analysis of CDS Coronal Loops

    NASA Astrophysics Data System (ADS)

    Kimble, J. A.; Schmelz, J. T.; Nasraoui, K.; Rightmire, L. A.; Andrews, J. M.; Cirtain, J. W.

    2008-05-01

    The coronal loop data used for this analysis was obtained using the Coronal Diagnostic Spectrometer (CDS) aboard the Solar and Heliospheric Observatory on 2003 January 17 at 14:24:43 UT. We use the Chianti atomic physics database and the hybrid coronal abundances to determine temperatures and densities for positions along several loops. We chose six pixels along each loop as well as background pixels. The intensities of the background pixels are subtracted from each loop pixel to isolate the emission from the loop pixel, and then spectral lines with significant contributions to the loop intensities are selected. The loops were then analyzed with a forward folding process to produce differential emission measure (DEM) curves. Emission measure loci plots and DEM automatic inversions are then used to verify those conclusions. We find different results for each of these loops. One appears to be isothermal at each loop position, and the temperature does not change with height. The second appears to be multithermal at each position and the third seems to be consistent with two DEM spikes, which might indicate that there are two isothermal loops so close together, that they are not resolved by CDS. Solar physics research at the University of Memphis is supported by a Hinode subcontract from NASA/SAO as well as NSF ATM-0402729.

  14. Development of optical diaphragm deflection sensors

    NASA Technical Reports Server (NTRS)

    Ghering, W. L.; Varshneya, D.; Jeffers, L. A.; Bailey, R. T.; Berthold, J. W.

    1985-01-01

    The objective of this project was to develop high-temperature pressure sensors using non-metallic components and optical sensing methods. The sensors are to operate over a temperature range from room temperature approx. 20C to 540C, to respond to internal pressure up to 690 kPa, to respond to external pressure up to 690 kPa, and to withstand external overpressure of 2070 kPa. Project tasks include evaluating sensing techniques and sensor systems. These efforts include materials and sensing method selection, sensor design, sensor fabrication, and sensor testing. Sensors are tested as a function of temperature, pressure, overpressure, and vibration. The project results show that high-temperature pressure sensors based on glass components and optical sensing methods are feasible. The microbend optical diaphragm deflection sensor exhibits the required sensitivity and stability for use as a pressure sensor with temperature compensation. for the microbend sensor, the 95% confidence level deviation of input pressure from the pressure calculated from the overall temperature-compensated calibration equation is 3.7% of full scale. The limitations of the sensors evaluated are primarily due to the restricted temperature range of suitable commercially available optical fibers and the problems associated with glass-to-metal pressure sealing over the entire testing temperature range.

  15. Photothermal deflection in a supercritical fluid

    NASA Astrophysics Data System (ADS)

    Briggs, Matthew E.; Gammon, Robert W.

    1994-11-01

    The total losses due to absorption and scatter from the best optical coatings can be made as low as deflection apparatus. The noise floor in our surface-absorption measurements using supercritical xenon, Tc equals 16.7 degree(s)C, corresponds to an absorptance A equals Pabsorbed/Pincident equals 10-10 under illumination of 1 W. Bulk absorption measurements are similarly enhanced: the noise floor corresponds to an absorption coefficient of (alpha) equals 10-13 cm-1 for 1 W of illumination in a sample of length 1 cm. These levels are three orders of magnitude more sensitive than any previously reported. The enhancement is brought about by the divergence in the coefficient of thermal expansion of a fluid near the critical point. In attempting to use this sensitivity to measure the absorption in transmission of low-absorbing (

  16. Throat Flow Modelling of Expansion Deflection Nozzles

    NASA Astrophysics Data System (ADS)

    Taylor, N. V.; Hempsell, C. M.

    Modelling of the supersonic flow within a rocket nozzle of both conventional and expansion deflection (ED) design is well handled by Method of Characteristics based algorithms. This approach provides both a predic- tion of the flowfield, and allows efficient optimisation of nozzle shape with respect to length. However, the Method of Characteristics requires a solution of the transonic flow through the nozzle throat to provide initial conditions, and the accuracy of the description of the transonic flow will clearly affect the overall accuracy of the complete nozzle flow calculation. However, it is relatively simple to show that conventional analytical methods for this process break down when applied to the more complex throat geometry of ED nozzles. This requires the use of a time marching solution method, which allows the analysis of the flow within this region even on such advanced configurations. This paper demonstrates this capability, outlines a general method for ED nozzle throat geometric definition, and examines the effect of various throat parameters on the permissible range of ED contours. It is found that the design of length optimised ED nozzles is highly sensitive to small changes in these parameters, and hence they must be selected with care.

  17. Magnetic separation of colloidal nanoparticle mixtures using a material specific peptide.

    PubMed

    Essinger-Hileman, Elizabeth R; Popczun, Eric J; Schaak, Raymond E

    2013-06-18

    A material specific peptide bound to Fe2O3 facilitates the selective sequestration of Au from a colloidal mixture of Au and CdS nanoparticles; the Au-Fe2O3 precipitate can then be magnetically separated from the colloidal CdS, and the Au nanoparticles can be recovered upon release from the Fe2O3. PMID:23661051

  18. Optical characterization of CdS nanorods capped with starch

    NASA Astrophysics Data System (ADS)

    Roy, J. S.; Pal Majumder, T.; Schick, C.

    2015-05-01

    Well crystalline uniform CdS nanorods were grown by changing the concentration of maize starch. The highly polymeric (branched) structure of starch enhances the growth of CdS nanorods. The average diameter of the nanorods is 20-25 nm while length is of 500-600 nm as verified from SEM and XRD observations. The optical band gaps of the CdS nanorods are varying from 2.66 eV to 2.52 eV depending on concentration of maize starch. The photoluminescence (PL) emission bands are shifted from 526 nm to 529 nm with concentration of maize starch. We have also observed the enhanced PL intensity in CdS nanorods capped with starch. The Fourier transform infrared (FTIR) spectroscopy shows the significant effect of starch on CdS nanorods.

  19. Spectroscopic Analysis of Impurity Precipitates in CdS Films

    SciTech Connect

    Webb, J. D.; Keane, J.; Ribelin, R.; Gedvilas, L.; Swartzlander, A.; Ramanathan, K.; Albin, D. S.; Noufi, R.

    1999-10-31

    Impurities in cadmium sulfide (CdS) films are a concern in the fabrication of copper (indium, gallium) diselenide (CIGS) and cadmium telluride (CdTe) photovoltaic devices. Devices incorporating chemical-bath-deposited (CBD) CdS are comparable in quality to devices incorporating purer CdS films grown using vacuum deposition techniques, despite the higher impurity concentrations typically observed in the CBD CdS films. In this paper, we summarize and review the results of Fourier transform infrared (FTIR), Auger, electron microprobe, and X-ray photoelectron spectroscopic (XPS) analyses of the impurities in CBD CdS films. We show that these impurities differ as a function of substrate type and film deposition conditions. We also show that some of these impurities exist as 10{sup 2} micron-scale precipitates.

  20. Biosynthesis of CdS nanoparticles in banana peel extract.

    PubMed

    Zhou, Guang Ju; Li, Shuo Hao; Zhang, Yu Cang; Fu, Yun Zhi

    2014-06-01

    Cadmium sulfide (CdS) nanoparticles (NPs) were synthesized by using banana peel extract as a convenient, non-toxic, eco-friendly 'green' capping agent. Cadmium nitrate and sodium sulfide are main reagents. A variety of CdS NPs are prepared through changing reaction conditions (banana extracts, the amount of banana peel extract, solution pH, concentration and reactive temperature). The prepared CdS colloid displays strong fluorescence spectrum. X-ray diffraction analysis demonstrates the successful formation of CdS NPs. Fourier transform infra-red (FTIR) spectrogram indicates the involvement of carboxyl, amine and hydroxyl groups in the formation of CdS NPs. Transmission electron microscope (TEM) result reveals that the average size of the NPs is around 1.48 nm. PMID:24738409

  1. Separable fastening device

    DOEpatents

    Harvey, Andrew C.; Ribich, William A.; Marinaccio, Paul J.; Sawaf, Bernard E.

    1987-12-01

    A separable fastener system has a first separable member that includes a series of metal hook sheets disposed in stacked relation that defines an array of hook elements on its broad surface. Each hook sheet is a planar metal member of uniform thickness and has a body portion with a series of hook elements formed along one edge of the body. Each hook element includes a stem portion, a deflecting surface portion, and a latch portion. Metal spacer sheets are disposed between the hook sheets and may be varied in thickness and in number to control the density of the hook elements on the broad surface of the first fastener member. The hook and spacer sheets are secured together in stacked relation. A second fastener member has a surface of complementary engaging elements extending along its broad surface which are releasably interengageable with the hook elements of the first fastener member, the deflecting surfaces of the hook elements of the first fastener member tending to deflect hook engaging portions of the second fastener member and the latch portions of the hook elements of the first fastener member engaging portions of the second fastener member in fastening relation.

  2. Coupler induced monopole component and its minimization in deflecting cavities

    NASA Astrophysics Data System (ADS)

    Ambattu, P. K.; Burt, G.; Grudiev, A.; Dolgashev, V.; Dexter, A.

    2013-06-01

    Deflecting cavities are used in particle accelerators for the manipulation of charged particles by deflecting or crabbing (rotating) them. For short deflectors, the effect of the power coupler on the deflecting field can become significant. The particular power coupler type can introduce multipole rf field components and coupler-specific wakefields. Coupler types that would normally be considered like standard on-cell coupler, waveguide coupler, or mode-launcher coupler could have one or two rf feeds. The major advantage of a dual-feed coupler is the absence of monopole and quadrupole rf field components in the deflecting structure. However, a dual-feed coupler is mechanically more complex than a typical single-feed coupler and needs a splitter. For most applications, deflecting structures are placed in regions where there is small space hence reducing the size of the structure is very desirable. This paper investigates the multipole field components of the deflecting mode in single-feed couplers and ways to overcome the effect of the monopole component on the beam. Significant advances in performance have been demonstrated. Additionally, a novel coupler design is introduced which has no monopole field component to the deflecting mode and is more compact than the conventional dual-feed coupler.

  3. Application of CdS quantum dots modified carbon paste electrode for monitoring the process of acetaminophen preparation.

    PubMed

    Pasandideh-Nadamani, M; Omrani, A; Sadeghi-Maleki, M R; Samadi-Maybodi, A

    2016-06-01

    In this research article, a novel, selective, and sensitive modified carbon paste electrode (CPE) using CdS quantum dots (QDs) is presented. The highly stable CdS QDs were successfully synthesized in an in situ process using Na2S2O3 as a precursor and thioglycolic acid as a catalyst and capping agent. The synthesis of CdS QDs was studied using X-ray diffraction (XRD) and transmission electron microscopy (TEM) techniques. The synthesized CdS QDs were used for preparation of a modified carbon paste electrode (CdS/CPE). The electrochemical behavior of the electrode toward p-aminophenol (PAP) and acetaminophen (Ac) was studied, and the results demonstrated that the CdS/CPE exhibited good electrocatalytic performance toward PAP and Ac oxidation. The oxidation peak potential of each analyte in the mixture was well separated. As a result, a selective and reliable method was developed for the determination of PAP and Ac simultaneously without any chemical separations. Application of the fabricated electrode for monitoring the process of Ac preparation from PAP was investigated. The obtained results show that CdS/CPE has satisfactory analytical performance; it could be a kind of attractive and promising nanomaterial-based sensor for process monitoring via the electrochemical approach. PMID:26945834

  4. Asteroid Deflection Mission Design Considering On-Ground Risks

    NASA Astrophysics Data System (ADS)

    Rumpf, Clemens; Lewis, Hugh G.; Atkinson, Peter

    The deflection of an Earth-threatening asteroid requires high transparency of the mission design process. The goal of such a mission is to move the projected point of impact over the face of Earth until the asteroid is on a miss trajectory. During the course of deflection operations, the projected point of impact will match regions that were less affected before alteration of the asteroid’s trajectory. These regions are at risk of sustaining considerable damage if the deflecting spacecraft becomes non-operational. The projected impact point would remain where the deflection mission put it at the time of mission failure. Hence, all regions that are potentially affected by the deflection campaign need to be informed about this risk and should be involved in the mission design process. A mission design compromise will have to be found that is acceptable to all affected parties (Schweickart, 2004). A software tool that assesses the on-ground risk due to deflection missions is under development. It will allow to study the accumulated on-ground risk along the path of the projected impact point. The tool will help determine a deflection mission design that minimizes the on-ground casualty and damage risk due to deflection operations. Currently, the tool is capable of simulating asteroid trajectories through the solar system and considers gravitational forces between solar system bodies. A virtual asteroid may be placed at an arbitrary point in the simulation for analysis and manipulation. Furthermore, the tool determines the asteroid’s point of impact and provides an estimate of the population at risk. Validation has been conducted against the solar system ephemeris catalogue HORIZONS by NASA’s Jet Propulsion Laboratory (JPL). Asteroids that are propagated over a period of 15 years show typical position discrepancies of 0.05 Earth radii relative to HORIZONS’ output. Ultimately, results from this research will aid in the identification of requirements for

  5. Ultrasensitive Beam Deflection Measurement via Interferometric Weak Value Amplification

    SciTech Connect

    Dixon, P. Ben; Starling, David J.; Jordan, Andrew N.; Howell, John C.

    2009-05-01

    We report on the use of an interferometric weak value technique to amplify very small transverse deflections of an optical beam. By entangling the beam's transverse degrees of freedom with the which-path states of a Sagnac interferometer, it is possible to realize an optical amplifier for polarization independent deflections. The theory for the interferometric weak value amplification method is presented along with the experimental results, which are in good agreement. Of particular interest, we measured the angular deflection of a mirror down to 400{+-}200 frad and the linear travel of a piezo actuator down to 14{+-}7 fm.

  6. The Extreme-Ultraviolet Solar Irradiance Spectrum Observed with the Coronal Diagnostic Spectrometer (CDS) on SOHO

    NASA Astrophysics Data System (ADS)

    Brekke, P.; Thompson, W. T.; Woods, T. N.; Eparvier, F. G.

    2000-06-01

    We present a calibrated solar EUV irradiance spectrum in the ranges 307-380 Å and 515-632 Å. The ``Sun as a star'' spectrum was recorded by the Coronal Diagnostic Spectrometer (CDS) on SOHO on 1997 May 15 using the normal incidence spectrometer (NIS) with a spectral resolution between 0.3 and 0.6 Å. The relatively high spectral resolution allows the separation of blends and the differentiation of weak emission lines. The full-disk spectrum is compared with simultaneous well-calibrated EUV irradiance measurements from a NASA/LASP rocket payload to validate the preflight calibration of CDS. Significant errors in the preflight calibration were found, and a new calibration has been established for the CDS/NIS system. The present spectrum includes emission lines formed in the temperature range 104 to over 106 K. Line fluxes for the most prominent lines are extracted for the calibration and for the solar irradiance studies. This measurement should represent well solar minimum conditions as the daily 10.7 cm radio flux was 73 (units of 10-22 W m-2 Hz-1). A modest spatial resolution, constrained by the observing mode used, allows for the discrimination between quiet and active sun. The calibrated quiet-Sun irradiance spectrum is compared with previous measurements.

  7. Computer Use May Help Deflect Seniors' Memory Problems

    MedlinePlus

    ... 157584.html Computer Use May Help Deflect Seniors' Memory Problems But, experts note that the study can' ... may help ward off age-related declines in memory and thinking, new research suggests. The study found ...

  8. High bandwidth deflection readout for atomic force microscopes.

    PubMed

    Steininger, Juergen; Bibl, Matthias; Yoo, Han Woong; Schitter, Georg

    2015-10-01

    This contribution presents the systematic design of a high bandwidth deflection readout mechanism for atomic force microscopes. The widely used optical beam deflection method is revised by adding a focusing lens between the cantilever and the quadrant photodetector (QPD). This allows the utilization of QPDs with a small active area resulting in an increased detection bandwidth due to the reduced junction capacitance. Furthermore the additional lens can compensate a cross talk between a compensating z-movement of the cantilever and the deflection readout. Scaling effects are analyzed to get the optimal spot size for the given geometry of the QPD. The laser power is tuned to maximize the signal to noise ratio without limiting the bandwidth by local saturation effects. The systematic approach results in a measured -3 dB detection bandwidth of 64.5 MHz at a deflection noise density of 62fm/√Hz. PMID:26520960

  9. High bandwidth deflection readout for atomic force microscopes

    NASA Astrophysics Data System (ADS)

    Steininger, Juergen; Bibl, Matthias; Yoo, Han Woong; Schitter, Georg

    2015-10-01

    This contribution presents the systematic design of a high bandwidth deflection readout mechanism for atomic force microscopes. The widely used optical beam deflection method is revised by adding a focusing lens between the cantilever and the quadrant photodetector (QPD). This allows the utilization of QPDs with a small active area resulting in an increased detection bandwidth due to the reduced junction capacitance. Furthermore the additional lens can compensate a cross talk between a compensating z-movement of the cantilever and the deflection readout. Scaling effects are analyzed to get the optimal spot size for the given geometry of the QPD. The laser power is tuned to maximize the signal to noise ratio without limiting the bandwidth by local saturation effects. The systematic approach results in a measured -3 dB detection bandwidth of 64.5 MHz at a deflection noise density of 62 fm / √{ Hz } .

  10. Shielded helix traveling wave cathode ray tube deflection structure

    DOEpatents

    Norris, N.J.; Hudson, C.L.

    1992-12-15

    Various embodiments of a helical coil deflection structure of a CRT are described and illustrated which provide shielding between adjacent turns of the coil on either three or four sides of each turn in the coil. Threaded members formed with either male or female threads and having the same pitch as the deflection coil are utilized for shielding the deflection coil with each turn of the helical coil placed between adjacent threads which act to shield each coil turn from adjacent turns and to confine the field generated by the coil to prevent or inhibit cross-coupling between adjacent turns of the coil to thereby prevent generation of fast fields which might otherwise deflect the beam out of time synchronization with the electron beam pulse. 13 figs.

  11. Shielded helix traveling wave cathode ray tube deflection structure

    DOEpatents

    Norris, Neil J.; Hudson, Charles L.

    1992-01-01

    Various embodiments of a helical coil deflection structure of a CRT are described and illustrated which provide shielding between adjacent turns of the coil on either three or four sides of each turn in the coil. Threaded members formed with either male or female threads and having the same pitch as the deflection coil are utilized for shielding the deflection coil with each turn of the helical coil placed between adjacent threads which act to shield each coil turn from adjacent turns and to confine the field generated by the coil to prevent or inhibit cross-coupling between adjacent turns of the coil to thereby prevent generation of fast fields which might otherwise deflect the beam out of time synchronization with the electron beam pulse.

  12. Limitation of linear colliders from transverse rf deflections

    SciTech Connect

    Seeman, J.T.

    1987-01-01

    Offaxis beam trajectories in a linear collider produce transverse wakefield and chromatic effects which cause emittance enlargement. One cause for non-centered trajectories in the accelerating structures is radial rf fields which produce transverse deflections. Static deflections can be compensated by static dipole magnetic fields. However, fluctuations of the rf fields cause variations in the deflections which must be managed or limited. Given the level of fluctuation of the phase and amplitude of an rf system, a limit on the allowable rf deflection can be calculated. Parameters, such as the beam emittance, lattice design, rf wavelength and the initial and final beam energies, influence the tolerances. Two tolerances are calculated: (1) one assumes that the wakefields are completely controlled, and that chromatic effects are the only enlarging mechanism (optimistic), and (2) the other assumes the limit is due to transverse wakefields without the aid of Landau damping (pessimistic).

  13. Towards efficient photoinduced charge separation in carbon nanodots and TiO2 composites in the visible region.

    PubMed

    Sun, Mingye; Qu, Songnan; Ji, Wenyu; Jing, Pengtao; Li, Di; Qin, Li; Cao, Junsheng; Zhang, Hong; Zhao, Jialong; Shen, Dezhen

    2015-03-28

    In this work, photoinduced charge separation behaviors in non-long-chain-molecule-functionalized carbon nanodots (CDs) with visible intrinsic absorption (CDs-V) and TiO2 composites were investigated. Efficient photoinduced electron injection from CDs-V to TiO2 with a rate of 8.8 × 10(8) s(-1) and efficiency of 91% was achieved in the CDs-V/TiO2 composites. The CDs-V/TiO2 composites exhibited excellent photocatalytic activity under visible light irradiation, superior to pure TiO2 and the CDs with the main absorption band in the ultraviolet region and TiO2 composites, which indicated that visible photoinduced electrons and holes in such CDs-V/TiO2 composites could be effectively separated. The incident photon-to-current conversion efficiency (IPCE) results for the CD-sensitized TiO2 solar cells also agreed with efficient photoinduced charge separation between CDs-V and the TiO2 electrode in the visible range. These results demonstrate that non-long-chain-molecule-functionlized CDs with a visible intrinsic absorption band could be appropriate candidates for photosensitizers and offer a new possibility for the development of a well performing CD-based photovoltaic system. PMID:25721932

  14. Double deflection system for an electron beam device

    DOEpatents

    Parker, Norman W.; Golladay, Steven D.; Crewe, Albert V.

    1978-01-01

    A double deflection scanning system for electron beam instruments is provided embodying a means of correcting isotropic coma, and anisotropic coma aberrations induced by the magnetic lens of such an instrument. The scanning system deflects the beam prior to entry into the magnetic lens from the normal on-axis intersection of the beam with the lens according to predetermined formulas and thereby reduces the aberrations.

  15. Design of Superconducting Parallel Bar Deflecting and Crabbing rf Structures

    SciTech Connect

    Jean Delayen, Haipeng Wang

    2009-05-01

    A new concept for a deflecting and crabbing rf structure based on half-wave resonant lines was introduced recently*. It offers significant advantages to existing designs and, because of it compactness, allows low frequency operation. This concept has been further refined and optimized for superconducting implementation. Results of this optimization and application to a 400 MHz crabbing cavity and a 499 MHz deflecting cavity are presented.

  16. Deflection, Frequency, and Stress Characteristics of Rectangular, Triangular, and Step Profile Microcantilevers for Biosensors

    PubMed Central

    Ansari, Mohd Zahid; Cho, Chongdu

    2009-01-01

    This study presents the deflection, resonant frequency and stress results of rectangular, triangular, and step profile microcantilevers subject to surface stress. These cantilevers can be used as the sensing element in microcantilever biosensors. To increase the overall sensitivity of microcantilever biosensors, both the deflection and the resonant frequency of the cantilever should be increased. The effect of the cantilever profile change and the cantilever cross-section shape change is first investigated separately and then together. A finite element code ANSYS Multiphysics is used and solid finite elements cantilever models are solved. A surface stress of 0.05 N/m was applied to the top surface of the cantilevers. The cantilevers are made of silicon with elastic modulus 130 GPa and Poisson’s ratio 0.28. To show the conformity of this study, the numerical results are compared against their analytical ones. Results show that triangular and step cantilevers have better deflection and frequency characteristics than rectangular ones. PMID:22454571

  17. Post mitigation impact risk analysis for asteroid deflection demonstration missions

    NASA Astrophysics Data System (ADS)

    Eggl, Siegfried; Hestroffer, Daniel; Thuillot, William; Bancelin, David; Cano, Juan L.; Cichocki, Filippo

    2015-08-01

    Even though mankind believes to have the capabilities to avert potentially disastrous asteroid impacts, only the realization of mitigation demonstration missions can validate this claim. Such a deflection demonstration attempt has to be cost effective, easy to validate, and safe in the sense that harmless asteroids must not be turned into potentially hazardous objects. Uncertainties in an asteroid's orbital and physical parameters as well as those additionally introduced during a mitigation attempt necessitate an in depth analysis of deflection mission designs in order to dispel planetary safety concerns. We present a post mitigation impact risk analysis of a list of potential kinetic impactor based deflection demonstration missions proposed in the framework of the NEOShield project. Our results confirm that mitigation induced uncertainties have a significant influence on the deflection outcome. Those cannot be neglected in post deflection impact risk studies. We show, furthermore, that deflection missions have to be assessed on an individual basis in order to ensure that asteroids are not inadvertently transported closer to the Earth at a later date. Finally, we present viable targets and mission designs for a kinetic impactor test to be launched between the years 2025 and 2032.

  18. All-optical optoacoustic microscopy system based on probe beam deflection technique

    NASA Astrophysics Data System (ADS)

    Maswadi, Saher M.; Tsyboulskic, Dmitri; Roth, Caleb C.; Glickman, Randolph D.; Beier, Hope T.; Oraevsky, Alexander A.; Ibey, Bennett L.

    2016-03-01

    It is difficult to achieve sub-micron resolution in backward mode OA microscopy using conventional piezoelectric detectors, because of wavefront distortions caused by components placed in the optical path, between the sample and the objective lens, that are required to separate the acoustic wave from the optical beam. As an alternate approach, an optoacoustic microscope (OAM) was constructed using the probe beam deflection technique (PBDT) to detect laserinduced acoustic signals. The all-optical OAM detects laser-generated pressure waves using a probe beam passing through a coupling medium, such as water, filling the space between the microscope objective lens and sample. The acoustic waves generated in the sample propagate through the coupling medium, causing transient changes in the refractive index that deflect the probe beam. These deflections are measured with a high-speed, balanced photodiode position detector. The deflection amplitude is directly proportional to the magnitude of the acoustic pressure wave, and provides the data required for image reconstruction. The sensitivity of the PBDT detector expressed as noise equivalent pressure was 12 Pa, comparable to that of existing high-performance ultrasound detectors. Because of the unimpeded working distance, a high numerical aperture objective lens, i.e. NA = 1, was employed in the OAM to achieve near diffraction-limited lateral resolution of 0.5 μm at 532nm. The all-optical OAM provides several benefits over current piezoelectric detector-based systems, such as increased lateral and axial resolution, higher sensitivity, robustness, and potentially more compatibility with multimodal instruments.

  19. RESONATOR PARTICLE SEPARATOR

    DOEpatents

    Blewett, J.P.

    1962-01-01

    A wave guide resonator structure is described for use in separating particles of equal momentum but differing in mass and having energies exceeding one billion electron volts. The particles are those of sub-atomic size and are generally produced as a result of the bombardment of a target by a beam such as protons produced in a high-energy accelerator. In this wave guide construction, the particles undergo preferential deflection as a result of the presence of an electric field. The boundary conditions established in the resonator are such as to eliminate an interfering magnetic component, and to otherwise phase the electric field to obtain a traveling wave such as one which moves at the same speed as the unwanted particle. The latter undergoes continuous deflection over the whole length of the device and is, therefore, eliminated while the wanted particle is deflected in opposite directions over the length of the resonator and is thus able to enter an exit aperture. (AEC)

  20. RESONATOR PARTICLE SEPARATOR

    DOEpatents

    Blewett, J.P.; Kiesling, J.D.

    1963-06-11

    A wave-guide resonator structure is designed for use in separating particles of equal momentum but differing in mass, having energies exceeding one billion eiectron volts. The particles referred to are those of sub-atomic size and are generally produced as a result of the bombardment of a target by a beam such as protons produced in a high energy accelerator. In the resonator a travelling electric wave is produced which travels at the same rate of speed as the unwanted particle which is thus deflected continuously over the length of the resonator. The wanted particle is slightly out of phase with the travelling wave so that over the whole length of the resonator it has a net deflection of substantially zero. The travelling wave is established in a wave guide of rectangular cross section in which stubs are provided to store magnetic wave energy leaving the electric wave energy in the main structure to obtain the desired travelling wave and deflection. The stubs are of such shape and spacing to establish a critical mathemitical relationship. (AEC)

  1. Rosetta observations of solar wind deflection in the coma

    NASA Astrophysics Data System (ADS)

    Broiles, Thomas; Burch, James; Clark, George; Goldstein, Raymond; Koenders, Christoph; Mandt, Kathleen; Mokashi, Prachet; Samara, Marilia

    2015-04-01

    Until recently, study of the solar wind around comets was limited to remote observations and brief in-situ encounters. With the arrival of Rosetta at the comet Churyumov-Gerasimenko (CG), we have had near constant solar wind observations at the comet for over 6 months. This is an unprecedented opportunity to study this dynamic interaction over time. Neutral atoms produced by the comet become ionized through photoionization or charge-exchange with the solar wind. The freshly ionized particles experience v x B electric field and begin to gyrate around the interplanetary magnetic field. Currently, CG is ~2.6 AU from the Sun, and as of this writing, neutral production is still relatively low. Consequently, most pickup ions are produced locally (< few hundred kilometers), and a diamagnetic cavity may not exist. Moreover, neutral production is variable and changes over the comet's rotational period. We find the following: 1) The solar wind is heavily deflected near the comet (in some cases >45° away from the anti-sunward direction). 2) The solar wind helium experiences less deflection than the protons. 3) The periodicity of the deflection is highly variable, and can vary over minutes or hours. From these results, we conclude that the solar wind is deflected by a mechanism very close to the comet. We suggest the following possibilities: 1) The solar wind could be deflected by a Lorenz force in the opposite direction to that experienced by the pickup ions, which would also conserve the momentum of the two fluid system. This would explain why solar wind protons are more strongly deflected than the heavier alpha particles. Additionally, this would explain the periodicity of the deflections, which would react to changes in the interplanetary magnetic field. 2) The solar wind deflection might occur from strong charging of comet's nucleus. In which case, the nucleus may charge both positively or negatively. The nucleus could charge positively due photoionization of the surface

  2. High precision differential measurement of surface photovoltage transients on ultrathin CdS layers.

    PubMed

    Dittrich, Th; Bönisch, S; Zabel, P; Dube, S

    2008-11-01

    Time-resolved surface photovoltage (SPV) is an important method for studying charge separation, for example, in nanostructured semiconductors. High precision differential measurement of SPV transients was realized with two identical measurement capacitors and high-impedance buffers. In addition, logarithmic readout and averaging procedures were implemented for single transients over eight magnitudes in time. As a model system ultrathin CdS layers were investigated. The thickness dependencies of the SPV amplitudes and that of the dominating relaxation mechanisms are demonstrated and discussed. PMID:19045899

  3. Guide Vanes for Deflecting Fluid Currents with Small Loss of Energy

    NASA Technical Reports Server (NTRS)

    Krober, G

    1933-01-01

    The transverse momentum of the deflected air stream to be absorbed is divided between the intermediate and outside walls, so that the pressure increase on each wall is much smaller and the danger of separation is diminished. The formation of secondary vortices is also diminished. By taking as the basis profiles with high c(sub a), such as have proved practically favorable, it is not possible to find a satisfactory form of grid simply on the assumption that the flow is potential. The requirements called for the most uniform possible velocity distribution behind the bend and the smallest possible losses.

  4. Hot electron induced NIR detection in CdS films

    NASA Astrophysics Data System (ADS)

    Sharma, Alka; Kumar, Rahul; Bhattacharyya, Biplab; Husale, Sudhir

    2016-03-01

    We report the use of random Au nanoislands to enhance the absorption of CdS photodetectors at wavelengths beyond its intrinsic absorption properties from visible to NIR spectrum enabling a high performance visible-NIR photodetector. The temperature dependent annealing method was employed to form random sized Au nanoparticles on CdS films. The hot electron induced NIR photo-detection shows high responsivity of ~780 mA/W for an area of ~57 μm2. The simulated optical response (absorption and responsivity) of Au nanoislands integrated in CdS films confirms the strong dependence of NIR sensitivity on the size and shape of Au nanoislands. The demonstration of plasmon enhanced IR sensitivity along with the cost-effective device fabrication method using CdS film enables the possibility of economical light harvesting applications which can be implemented in future technological applications.

  5. Hot electron induced NIR detection in CdS films.

    PubMed

    Sharma, Alka; Kumar, Rahul; Bhattacharyya, Biplab; Husale, Sudhir

    2016-01-01

    We report the use of random Au nanoislands to enhance the absorption of CdS photodetectors at wavelengths beyond its intrinsic absorption properties from visible to NIR spectrum enabling a high performance visible-NIR photodetector. The temperature dependent annealing method was employed to form random sized Au nanoparticles on CdS films. The hot electron induced NIR photo-detection shows high responsivity of ~780 mA/W for an area of ~57 μm(2). The simulated optical response (absorption and responsivity) of Au nanoislands integrated in CdS films confirms the strong dependence of NIR sensitivity on the size and shape of Au nanoislands. The demonstration of plasmon enhanced IR sensitivity along with the cost-effective device fabrication method using CdS film enables the possibility of economical light harvesting applications which can be implemented in future technological applications. PMID:26965055

  6. Enhanced electron spin rotation in CdS quantum dots.

    PubMed

    Masumoto, Yasuaki; Umino, Hikaru; Sun, Jianhui; Suzumura, Eri

    2015-10-14

    We studied the spin rotation of electrons in CdS quantum dots (QDs) and CdS QDs with charge acceptors by means of time-resolved Faraday rotation (TRFR) at room temperature. The electron spin rotation had an oscillatory component in the TRFR signal and the oscillation frequency proportional to the magnetic field gave a g-factor of the electrons of 1.965 ± 0.006. The non-oscillatory component came from the population of excitons and showed an additional decay in CdS QDs with hole acceptors. The electron spin rotation signal was largely enhanced and lasted for a spin coherence time of T2* = 450 ps in CdS QDs tethered to TiO2 electron acceptors, where the spin initialization was triggered by the positive trion transition. These results give clear evidence that the electron spin rotation signal in QDs can be enhanced by transient p-doping. PMID:26352679

  7. Hot electron induced NIR detection in CdS films

    PubMed Central

    Sharma, Alka; Kumar, Rahul; Bhattacharyya, Biplab; Husale, Sudhir

    2016-01-01

    We report the use of random Au nanoislands to enhance the absorption of CdS photodetectors at wavelengths beyond its intrinsic absorption properties from visible to NIR spectrum enabling a high performance visible-NIR photodetector. The temperature dependent annealing method was employed to form random sized Au nanoparticles on CdS films. The hot electron induced NIR photo-detection shows high responsivity of ~780 mA/W for an area of ~57 μm2. The simulated optical response (absorption and responsivity) of Au nanoislands integrated in CdS films confirms the strong dependence of NIR sensitivity on the size and shape of Au nanoislands. The demonstration of plasmon enhanced IR sensitivity along with the cost-effective device fabrication method using CdS film enables the possibility of economical light harvesting applications which can be implemented in future technological applications. PMID:26965055

  8. The Maximal Deflection on an Ellipse

    ERIC Educational Resources Information Center

    Kalman, Dan

    2006-01-01

    At each point of an ellipse one can attach a normal vector and a radial vector, the latter defined as the vector from the center of the ellipse. At the ends of the major and minor axes, the two vectors coincide, but at all other points they are separated by an angle [delta]. What is the maximum value that [delta] can attain, and where does it…

  9. Deflection-Compensating Beam for use inside a Cylinder

    NASA Technical Reports Server (NTRS)

    Goodman, Dwight; Myers, Neill; Herren, Kenneth

    2008-01-01

    A design concept for a beam for a specific application permits variations and options for satisfying competing requirements to minimize certain deflections under load and to minimize the weight of the beam. In the specific application, the beam is required to serve as a motion-controlled structure for supporting a mirror for optical testing in the lower third portion of a horizontal, cylindrical vacuum chamber. The cylindrical shape of the chamber is fortuitous in that it can be (and is) utilized as an essential element of the deflection-minimizing design concept. The beam is, more precisely, a table-like structure comprising a nominally flat, horizontal portion with vertical legs at its ends. The weights of the beam and whatever components it supports are reacted by the contact forces between the lower ends of the legs and the inner cylindrical chamber wall. Whereas the bending moments arising from the weights contribute to a beam deflection that is concave with its lowest point at midlength, the bending moments generated by the contact forces acting on the legs contribute to a beam deflection that is convex with its highest point at midlength. In addition, the bending of the legs in response to the weights causes the lower ends of the legs to slide downward on the cylindrical wall. By taking the standard beam-deflection equations, combining them with the geometric relationships among the legs and the horizontal portion of the beam, and treating the sliding as a component of deflection, it is possible to write an equation for the net vertical deflection as a function of the load and of position along the beam. A summary of major conclusions drawn from the equation characterization is included.

  10. Principle of Equivalence and the Deflection of Light by the Sun

    ERIC Educational Resources Information Center

    Comer, Robert P.; Lathrop, John D.

    1978-01-01

    Explains the discrepancy between the principle-of-equivalence and the general theory of relativity in calculating the deflection of light by the sun. Shows that the total deflection is the sum of the deflection given by the principle-of-equivalence, and the deflection of infinitely fast particles. ( GA)

  11. Facile Synthesis of Monodisperse CdS Nanocrystals via Microreaction

    NASA Astrophysics Data System (ADS)

    Wan, Zhen; Yang, Hongwei; Luan, Weiling; Tu, Shan-Tung; Zhou, Xinggui

    2010-01-01

    CdS-based nanocrystals (NCs) have attracted extensive interest due to their potential application as key luminescent materials for blue and white LEDs. In this research, the continuous synthesis of monodisperse CdS NCs was demonstrated utilizing a capillary microreactor. The enhanced heat and mass transfer in the microreactor was useful to reduce the reaction temperature and residence time to synthesize monodisperse CdS NCs. The superior stability of the microreactor and its continuous operation allowed the investigation of synthesis parameters with high efficiency. Reaction temperature was found to be a key parameter for balancing the reactivity of CdS precursors, while residence time was shown to be an important factor that governs the size and size distribution of the CdS NCs. Furthermore, variation of OA concentration was demonstrated to be a facile tuning mechanism for controlling the size of the CdS NCs. The variation of the volume percentage of OA from 10.5 to 51.2% and the variation of the residence time from 17 to 136 s facilitated the synthesis of monodisperse CdS NCs in the size range of 3.0-5.4 nm, and the NCs produced photoluminescent emissions in the range of 391-463 nm.

  12. The CGC enantiomer separation of 2-arylcarboxylic acid esters by using β-cyclodextrin derivatives as chiral stationary phases.

    PubMed

    Shi, Xueyan; Liu, Feipeng; Mao, Jianyou

    2016-03-17

    Chiral 2-arylcarboxylic acid esters are important intermediates in preparation of enantioenriched 2-arylpropionic acids type Non-steroidal anti-inflammatory drugs (NSAIDs). Enantiomer separation of 2-arylcarboxylic acid esters is crucial for evaluation of the asymmetric synthesis efficiency and the enantiomer excess of chiral 2-arylcarboxylic acid derivatives. The capillary gas chromatography (CGC) enantiomer separation of 17 pairs of 2-arylcarboxylic acid esters enantiomers was conducted by using seven different β-cyclodextrin derivatives (CDs) as chiral stationary phases. It was found that for the 7 pairs of 2-phenylpropionates enantiomers, CDs with both alkyl and acyl substituents especially 2,6-di-O-pentyl-3-O-butyryl-β-cyclodextrin exhibited better enantiomer separation abilities than the other CDs examined. For the 7 pairs of 2-(4-substituted phenyl)propionates enantiomers, 2,3,6-tri-O-methyl-β-cyclodextrin possessed better enantiomer separation abilities than the other CDs. Among the 3 pairs of 2-phenylbutyrates enantiomers examined, only methyl 2-phenylbutyrate enantiomers could be separated by three CDs among the 7 CDs tested, while enantiomers of ethyl 2-phenylbutyrate and isopropyl 2-phenylbutyrate couldn't be separated by any of the 7 CDs tested. Besides the structures of CDs, the structures of 2-arylcarboxylic acid esters including different ester moieties, substituents of phenyl, and different carboxylic acids moieties in 2-arylcarboxylic acid esters also affected the enantiomer separation results greatly. The CGC enantiomer separation results of 2-arylcarboxylic acid esters on different CDs are useful for solving the enantiomer separation problem of 2-arylcarboxylic acid esters. PMID:26920785

  13. Quantitative Analysis of CME Deflections in the Corona

    NASA Astrophysics Data System (ADS)

    Gui, Bin; Shen, Chenglong; Wang, Yuming; Ye, Pinzhong; Liu, Jiajia; Wang, Shui; Zhao, Xuepu

    2011-07-01

    In this paper, ten CME events viewed by the STEREO twin spacecraft are analyzed to study the deflections of CMEs during their propagation in the corona. Based on the three-dimensional information of the CMEs derived by the graduated cylindrical shell (GCS) model (Thernisien, Howard, and Vourlidas in Astrophys. J. 652, 1305, 2006), it is found that the propagation directions of eight CMEs had changed. By applying the theoretical method proposed by Shen et al. ( Solar Phys. 269, 389, 2011) to all the CMEs, we found that the deflections are consistent, in strength and direction, with the gradient of the magnetic energy density. There is a positive correlation between the deflection rate and the strength of the magnetic energy density gradient and a weak anti-correlation between the deflection rate and the CME speed. Our results suggest that the deflections of CMEs are mainly controlled by the background magnetic field and can be quantitatively described by the magnetic energy density gradient (MEDG) model.

  14. Deflected Propagation ---- A Factor Deciding the Geoeffectiveness of A CME

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Shen, C.; Liu, J.; Gui, B.; Wang, S.

    2010-12-01

    To answer the question if a CME can cause a significant change of the states of geo-space, the first issue we have to address is whether or not the CME will intersect with the Earth or what the trajectory of the CME is. From several observational cases and statistical studies, we show that the deflected propagations of CMEs are a common phenomenon. The amount of the deflection could be as large as several tens degrees in either latitude, longitude or both. Thus, an on-disk CME may not necessarily encounter the Earth, while a limb CME may be able to hit the Earth. Roughly, the CMEs' deflections can be classified as two different kinds. One is the deflection occurring in the corona, in which the CME's trajectory is controled by the distribution of the energy density of undisturbed coronal magnetic field. The other is that happenning in the IP space and in the ecliptic plane, in which the direction of the CME's propagation will be changed by the preceding or trailing background solar wind plasma depending on the velocity difference between the CME and ambient solar wind. Two models are proposed to describe the two different CME deflection behaviors, respectively. By applying the models to several cases, we may show that the trajectories of these CMEs predicted by the models match the observations fairly well.

  15. Photocurrent spectroscopy of CdS nanosheets

    NASA Astrophysics Data System (ADS)

    Kumar, P.; Wade, A.; Jackson, H. E.; Smith, L. M.; Rice, J. Yarrison; Choi, Y.-J.; Park, J.-G.

    2011-03-01

    We study the photocurrent from photoexcited charge carriers in CdS nanosheet (NS) structures. Metal-semiconductor-metal nanodevices are made with both Schottky and Ohmic contacts using photolithography followed by Ti/Al (20nm/200nm) metal evaporation and lift-off. Ohmic contacts are formed by Ar ion bombardment before the metal deposition to create donor sulfur vacancies which increases the electron concentration. Photocurrent spectra using a white light source filtered by a monochrometer show excitonic resonances at low temperatures corresponding to each of the A, B, and C hole bands. The photocurrent increases linearly with power for above gap excitation, and nonlinearly (quadratic) with laser power for below gap excitation, consistent with two-photon absorption with a nonlinear coefficient of β = 2 cm/GW. A wavelength dependence of the photocurrent with sub-band gap excitation to find the resonances and hence band structure is in progress. We acknowledge the financial support of the National Science Foundation through grants DMR-0806700, 0806572 and ECCS-0701703, and the KIST institutional research program 2E21060R.

  16. Large and small deflections of a cantilever beam

    NASA Astrophysics Data System (ADS)

    Beléndez, Tarsicio; Neipp, Cristian; Beléndez, Augusto

    2002-05-01

    The classical problem of the deflection of a cantilever beam of linear elastic material, under the action of an external vertical concentrated load at the free end, is analysed. We present the differential equation governing the behaviour of this physical system and show that this equation, although straightforward in appearance, is in fact rather difficult to solve due to the presence of a non-linear term. In this sense, this system is similar to another well known physical system: the simple pendulum. An approximation of the behaviour of a cantilever beam for small deflections was obtained from the equation for large deflections, and we present various numerical results for both cases. Finally, we compare the theoretical results with the experimental results obtained in the laboratory.

  17. A wideband deflected reflection based on multiple resonances

    NASA Astrophysics Data System (ADS)

    Chen, Hongya; Ma, Hua; Wang, Jiafu; Qu, Shaobo; Li, Yongfeng; Wang, Jun; Yan, Mingbao; Pang, Yongqiang

    2015-07-01

    We propose to realize wideband deflected reflection in microwave regime through multiple resonances. A wideband deflected reflection of a phase gradient metasurface is designed using a double-head arrow structure, which has demonstrated an ultra-wideband cross-polarized reflection caused by multiple electric and magnetic resonances. The wideband effect benefits from the wideband cross-polarized reflection and flexible phase modulation of the double-head arrow structure. Simulated and experimental results agree well with theoretical predictions. Furthermore, relative bandwidths of deflected reflection reach to 71 % for both x- and y-polarized waves under normal incidence. Our method of expansion bandwidth may pave the way in many practical applications, such as RCS reduction, stealth surfaces.

  18. Development of pneumatic thrust-deflecting powered-lift systems

    NASA Technical Reports Server (NTRS)

    Englar, R. J.; Nichols, J. H., Jr.; Harris, M. J.; Eppel, J. C.; Shovlin, M. D.

    1986-01-01

    Improvements introduced into the Circulation Control Wing/Upper Surface Blowing (CCW/USB) STOL concept (Harris et al., 1982) are described along with results of the full-scale static ground tests and model-scale wind tunnel investigations. Tests performed on the full-scale pneumatic thrust-deflecting system installed on the NASA QSRA aircraft have demonstrated that, relative to the original baseline configuration, a doubling of incremental thrust deflection due to blowing resulted from improvements that increased the blowing span and momentum, as well as from variations in blowing slot height and geometry of the trailing edge. A CCW/Over the Wing model has been built and tested, which was shown to be equivalent to the CCW/USB system in terms of pneumatic thrust deflection and lift generation, while resolving the problem of cruise thrust loss due to exhaust scrubbing on the wing upper surface.

  19. Analysis of the Deflection of CMEs by Coronal Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Liewer, Paulett C.; Panasenco, O.; Vourlidas, A.

    2013-07-01

    Understanding coronal influences on the direction of propagation of CMEs is important for space weather prediction. It is well known that CMEs often propagate non-radially, e.g., they do not move out radially from the location of the solar source (see, e.g., Cremades and Bothmer, A&A, 2004; Panasenco et al., Sol. Phys. 2013). There is evidence that most CMEs exit the corona in the minimum field region surrounding the coronal/heliospheric current sheet (HCS). If this is the case, then the degree of deflection should reflect the distance of the source region from the current sheet region. Here we study the observed deflection in latitude of four CMEs using STEREO/SECCHI’s EUV and white light observations to trace the deflection. A potential-field source surface (PFSS) model (Schrijver & DeRosa, Sol. Phys. 2003) is used to give information on the magnetic forces acting on the CME at different heights in the lower corona. This model, as well as the PFSS model results at the GONG website (http://gong.nso.edu/data/magmap/archive.html) and the coronal observations from STEREO, are used to try to determine the location of the HCS. For the events studied, we find cases when the deflection is gradual (occurring between the surface at several solar radii) and cases where the deflection is immediate (within ~1.5 solar radii). There are many cases in the literature where CMEs originating at high latitude are deflected towards the ecliptic and eventually impact Earth. Several of the CMEs we analyzed were later detected in situ at ~1 AU and we compare the near-Sun trajectory information to the trajectory information determine from the in situ information.

  20. Experimental testing and computational modeling of flat oval duct deflection

    SciTech Connect

    Smolinski, P.J.; Palmer, G.S.

    1998-10-01

    The deflection characteristics of spiral seam flat oval HVAC duct are examined in this study, and the effects of duct size, wall thickness, and the size spacing, and type of external reinforcement on the duct deformation are investigated. A duct test setup and a deflection measurement frame were developed for measuring the deformation of flat oval duct, and experimental testing was performed on a variety of duct configurations to measure the duct deflections at various positive and negative internal pressures. Finite element computer models of the ducts were developed to predict the deflections. The correlation between the predictions of the computer model and the data from the experimental testing is highly variable with differences ranging from a few percent to several hundred percent. In general, it was found that there was closer agreement between the finite element results and the experimental measurements for smaller duct and at locations of type 2 external reinforcements. This may be due to the fact that the finite element model assumed the idealized flat oval shape and this shape was better matched by smaller ducts and near the external reinforcement. It was also found that in some cases, unreinforced duct could achieve higher pressures than type 1 reinforced duct before exceeding the deflection limits. Sources of error include the uneven surface of the mastic in the measurement of the duct joint deflection and the variance of the actual duct shape from the idealized shape used in the finite element model. This study did not examine the variability of the experimental results due to differences in duct shape or manufacture.

  1. A large deflection model for the pull-in analysis of electrostatically actuated microcantilever beams

    NASA Astrophysics Data System (ADS)

    Chaterjee, S.; Pohit, G.

    2009-05-01

    A comprehensive model of an electrostatically actuated microcantilever beam separated from the ground plane by relatively larger gap is formulated accounting for the nonlinearities of the system arising out of electric forces, geometry of the deflected beam and the inertial terms. Since the gap is relatively large, the electrostatic model is formulated incorporating higher order correction of electrostatic forces. First static analysis is carried out to match the results obtained from the proposed model with the results provided by other researchers. It is observed that reduced order model exhibits good convergence when five or more number of modes is considered for the analysis. Dynamic analysis of the model is performed with five modes. The study indicates that although electrostatic forces cause softening characteristics whereas geometric nonlinearity produces stiffening effect on the microstructure, the nonlinearities play a significant role when pull-in occurs. The consideration of slope and curvature of deformable electrode for modelling the electrostatic forces for large gap separations predicts more accurate results. For applications in and around pull-in zone, the large deflection model needs to be considered for effective design.

  2. Nuclear cycler: An incremental approach to the deflection of asteroids

    NASA Astrophysics Data System (ADS)

    Vasile, Massimiliano; Thiry, Nicolas

    2016-04-01

    This paper introduces a novel deflection approach based on nuclear explosions: the nuclear cycler. The idea is to combine the effectiveness of nuclear explosions with the controllability and redundancy offered by slow push methods within an incremental deflection strategy. The paper will present an extended model for single nuclear stand-off explosions in the proximity of elongated ellipsoidal asteroids, and a family of natural formation orbits that allows the spacecraft to deploy multiple bombs while being shielded by the asteroid during the detonation.

  3. The 1919 measurement of the deflection of light

    NASA Astrophysics Data System (ADS)

    Will, Clifford M.

    2015-06-01

    The measurement of the deflection of starlight during a total solar eclipse on 29 May 1919 was the first verification of general relativity by an external team of scientists, brought Einstein and his theory to the attention of the general public, and left a legacy of experimental testing that continues today. The discovery of gravitational lenses turned Einstein's deflection into an important tool for astronomy and cosmology. This article reviews the history of the 1919 measurement and other eclipse measurements, describes modern measurements of the effect using radio astronomy, and of its cousin, the Shapiro time delay, and discusses the discovery and impact of gravitational lenses.

  4. Optical caliper with compensation for specimen deflection and method

    DOEpatents

    Bernacki, Bruce E.

    1997-01-01

    An optical non-contact profilometry system and method provided by an optical caliper with matched optical sensors that are arranged conjugate to each other so that the surface profile and thickness of an article can be measured without using a fixed reference surface and while permitting the article to deflect in space within the acquisition range of the optical sensors. The output signals from the two optical sensors are algebraically added to compensate for any such deflection of the article and provide a so compensated signal, the balance and sign of which provides a measurement of the actual thickness of the article at the optical sensors.

  5. Optical caliper with compensation for specimen deflection and method

    DOEpatents

    Bernacki, B.E.

    1997-12-09

    An optical non-contact profilometry system and method provided by an optical caliper with matched optical sensors that are arranged conjugate to each other so that the surface profile and thickness of an article can be measured without using a fixed reference surface and while permitting the article to deflect in space within the acquisition range of the optical sensors. The output signals from the two optical sensors are algebraically added to compensate for any such deflection of the article and provide a so compensated signal, the balance and sign of which provides a measurement of the actual thickness of the article at the optical sensors. 2 figs.

  6. A 3-dimensional time-resolved photothermal deflection ``Mirage'' method

    NASA Astrophysics Data System (ADS)

    Astrath, N. G. C.; Malacarne, L. C.; Lukasievicz, G. V. B.; Bernabe, H. S.; Rohling, J. H.; Baesso, M. L.; Shen, J.; Bialkowski, S. E.

    2012-02-01

    A three-dimensional time-resolved theory and experiment for photothermal deflection spectroscopy is developed. The heat conduction equations for two semi-infinite media consisting of an opaque sample and a fluid are solved considering temperature and energy flux balance conditions for a Gaussian heat source. The time dependent perpendicular deflection signal is calculated and compared to experimental measurements on glassy carbon and copper samples. Excellent agreement with literature values for thermal diffusivity of the samples is found. The transient behavior is analyzed for different coupling fluids.

  7. Fast scan control for deflection type mass spectrometers

    NASA Technical Reports Server (NTRS)

    Yeager, P. R.; Gaetano, G.; Hughes, D. B. (Inventor)

    1974-01-01

    A high speed scan device is reported that allows most any scanning sector mass spectrometer to measure preselected gases at a very high sampling rate. The device generates a rapidly changing staircase output which is applied to the accelerator of the spectrometer and it also generates defocusing pulses that are applied to one of the deflecting plates of the spectrometer which when shorted to ground deflects the ion beam away from the collector. A defocusing pulse occurs each time there is a change in the staircase output.

  8. Multiplexed Force and Deflection Sensing Shell Membranes for Robotic Manipulators

    NASA Technical Reports Server (NTRS)

    Park, Yong-Lae; Black, Richard; Moslehi, Behzad; Cutkosky, Mark; Chau, Kelvin

    2012-01-01

    Force sensing is an essential requirement for dexterous robot manipulation, e.g., for extravehicular robots making vehicle repairs. Although strain gauges have been widely used, a new sensing approach is desirable for applications that require greater robustness, design flexibility including a high degree of multiplexibility, and immunity to electromagnetic noise. This invention is a force and deflection sensor a flexible shell formed with an elastomer having passageways formed by apertures in the shell, with an optical fiber having one or more Bragg gratings positioned in the passageways for the measurement of force and deflection.

  9. Light-stimulated carrier dynamics of CuInS2/CdS heterotetrapod nanocrystals

    NASA Astrophysics Data System (ADS)

    Sakamoto, Masanori; Inoue, Koki; Okano, Makoto; Saruyama, Masaki; Kim, Sungwon; So, Yeong-Gi; Kimoto, Koji; Kanemitsu, Yoshihiko; Teranishi, Toshiharu

    2016-05-01

    We synthesized a heterotetrapod composed of a chalcopyrite(ch)-CuInS2 core and wurtzite(w)-CdS arms and elucidated its optical properties and light-stimulated carrier dynamics using fs-laser flash photolysis. The CuInS2/CdS heterotetrapod possessed quasi-type II band alignment, which caused much longer-lived charge separation than that in the isolated CuInS2 nanocrystal.We synthesized a heterotetrapod composed of a chalcopyrite(ch)-CuInS2 core and wurtzite(w)-CdS arms and elucidated its optical properties and light-stimulated carrier dynamics using fs-laser flash photolysis. The CuInS2/CdS heterotetrapod possessed quasi-type II band alignment, which caused much longer-lived charge separation than that in the isolated CuInS2 nanocrystal. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr01097k

  10. Deflection jounce bumper for strut suspension

    SciTech Connect

    Hassan, M.

    1987-07-21

    A suspension system is described for a vehicle including sprung and unsprung masses, the masses being separated by a spring bumper, the masses being located by a rod means so that distortion of the spring bumper occurs principally by axial compression. The bumper comprises an integral generally cylindrical body of elastic material such as rubber having opposed upper and lower end faces, the bumper having a solid upper hub portion closely encircling the rod means and a lower impact portion. The lower impact portion includes a cylindrical outer wall section and a cylindrical inner wall section concentrically disposed about the rod means and defining an intermediate cylindrical downwardly opening channel of predetermined radial extent and axial depth. The wall sections are integrally connected by axially extending uniformly spaced paired bridging segments. Each pair of segments in the form of a pair of mirror image arcuate segments symmetrically disposed about a vertically extending column axis. Each pair of segments defines adjacent interconnecting portion of the inner and outer walls, an axial column blind bore with the pair of segments having their center of curvature on their associated column bore axis. When aid bumper is impacted, the inner and outer wall sections together with the column-like arcuate bridging segments stretching to absorb impact energy providing initially high dampening load displacement resistance.

  11. Orthogonally interdigitated shielded serpentine travelling wave cathode ray tube deflection structure

    DOEpatents

    Hagen, E.C.; Hudson, C.L.

    1995-07-25

    A new deflection structure which deflects a beam of charged particles, such as an electron beam, includes a serpentine set for transmitting a deflection field, and a shielding frame for housing the serpentine set. The serpentine set includes a vertical serpentine deflection element and a horizontal serpentine deflection element. These deflection elements are identical, and are interdigitatedly and orthogonally disposed relative to each other, for forming a central transmission passage, through which the electron beam passes, and is deflected by the deflection field, so as to minimize drift space signal distortion. The shielding frame includes a plurality of ground blocks, and forms an internal serpentine trough within these ground blocks, for housing the serpentine set. The deflection structure further includes a plurality of feedthrough connectors which are inserted through the shielding frame, and which are electrically connected to the serpentine set. 10 figs.

  12. Orthogonally interdigitated shielded serpentine travelling wave cathod ray tube deflection structure

    SciTech Connect

    Hagen, E.C.; Hudson, C.L.

    1993-10-27

    This invention comprises a new deflection structure which deflects a beam of charged particles, such as an electron beam, includes a serpentine set for transmitting a deflection field, and shielding frame for housing the serpentine set. The serpentine set includes a vertical serpentine deflection element and a horizontal serpentine deflection element. These deflection elements are identical and are interdigitatedly and orthogonally disposed relative to each other, for forming a central transmission passage, through which the electron beam passes and is deflected by the deflection field to minimize drift space signal distortion. The shielding frame includes a plurality of ground blocks and forms an internal serpentine trough within these ground blocks for housing the serpentine set. The deflection structure further includes a plurality of feedthrough connectors which are inserted through the shielding frame and which are electrically connected to the serpentine set.

  13. Hot flow anomaly formation by magnetic deflection. [regions of hot plasma in earth magnetosphere

    NASA Technical Reports Server (NTRS)

    Onsager, T. G.; Thomsen, M. F.; Winske, D.

    1990-01-01

    Hot flow anomalies (HFAs) are localized plasma structures observed in the solar wind and magnetosheath near the earth's quasi-parallel bow shock. This paper presents one-dimensional hybrid computer simulations illustrating a formation mechanism for HFAs in which the single hot ion population results from a spatial separation of two counterstreaming ion beams. The higher-density cooler regions are dominated by the background (solar wind) ions, and the lower-density hotter internal regions are dominated by the beam ions. The spatial separation of the beam and background is caused by the deflection of the ions in large-amplitude magnetic fields which are generated by ion/ion streaming instabilities.

  14. Subminiature deflection circuit operates integrated sweep circuits in TV camera

    NASA Technical Reports Server (NTRS)

    Schaff, F. L.

    1967-01-01

    Small magnetic sweep deflection circuits operate a hand-held lunar television camera. They convert timing signals from the synchronizer into waveforms that provide a raster on the vidicon target. Raster size remains constant and linear during wide voltage and temperature fluctuations.

  15. Deflection of Light by Gravity: A Physical Approach.

    ERIC Educational Resources Information Center

    Diamond, Joshua B.

    1982-01-01

    Einstein's equivalence principle relates effects seen by an accelerating observer to those experienced by an observer in a gravitational field, providing an explanation of bending of a light beam by gravity. Because the calculations lead to results one-half the value found experimentally, obtaining the correct light deflection is discussed.…

  16. Damping of unwanted modes in SRF deflecting/crabbing cavities

    SciTech Connect

    Burt, Graeme; Wang, Haipeng

    2014-01-01

    As deflecting and crab cavities do not use the fundamental acceleration mode for their operation, the spectrum of unwanted modes is significantly different from that of accelerating cavities. The fundamental acceleration mode is now unwanted and can cause energy spread in the beam; in addition this mode frequency is often close to or lower than that of the deflecting mode, making it difficult to damp. This is made more complex in some of the compact crab cavities as there small beampipes often attenuate the fields very sharply. In addition in some crab cavities there can be an orthogonal transverse mode similar to the deflecting mode, known as the same order mode. The degeneracy of these modes must be split by polarising the cavity and if the polarisation is not large enough, dampers should be placed at either an electric or magnetic field null of the crabbing mode to effectively damp the unwanted polarisation. Various concepts for dealing with unwanted modes in various SRF deflecting cavities will be reviewed.

  17. Deflection circuit monitors force on object under water

    NASA Technical Reports Server (NTRS)

    Roller, R.; Yaroshuk, N.

    1968-01-01

    Capsule containing samples for radiation testing is guided under through a seal to an exact position within a nuclear reactor. A Linear Variable Differential Transformer /LVDT/ flexplate deflection circuit monitors the force on the capsule as it is positioned within the reactor.

  18. 30 CFR 7.47 - Deflection temperature test.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Deflection temperature test. 7.47 Section 7.47... temperature test. (a) Test procedures. (1) Prepare two samples for testing that measure 5 inches by 1/2 inch... which are 4 inches apart and immersed in a heat transfer medium at a test temperature range of 65...

  19. On guided versus deflected fields in controlled-source electromagnetics

    NASA Astrophysics Data System (ADS)

    Swidinsky, Andrei

    2015-06-01

    The detection of electrically resistive targets in applied geophysics is of interest to the hydrocarbon, mining and geotechnical industries. Elongated thin resistive bodies have been extensively studied in the context of offshore hydrocarbon exploration. Such targets guide electromagnetic fields in a process which superficially resembles seismic refraction. On the other hand, compact resistive bodies deflect current in a process which has more similarities to diffraction and scattering. The response of a real geological structure is a non-trivial combination of these elements-guiding along the target and deflection around its edges. In this note the electromagnetic responses of two end-member models are compared: a resistive layer, which guides the electromagnetic signal, and a resistive cylinder, which deflects the fields. Results show that the response of a finite resistive target tends to saturate at a much lower resistivity than a resistive layer, under identical survey configurations. Furthermore, while the guided electromagnetic fields generated by a buried resistive layer contain both anomalous horizontal and vertical components, the process of electromagnetic deflection from a buried resistive cylinder creates mainly anomalous vertical fields. Finally, the transmitter orientation with respect to the position of a finite body is an important survey parameter: when the distance to the target is much less than the host skin depth, a transmitter pointing towards the resistive cylinder will produce a stronger signal than a transmitter oriented azimuthally with respect to the cylinder surface. The opposite situation is observed when the distance to the target is greater than the host skin depth.

  20. 30 CFR 7.47 - Deflection temperature test.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Deflection temperature test. 7.47 Section 7.47 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Battery Assemblies § 7.47...

  1. 30 CFR 7.47 - Deflection temperature test.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Deflection temperature test. 7.47 Section 7.47 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Battery Assemblies § 7.47...

  2. 75 FR 12981 - Eligibility for Commercial Flats Failing Deflection

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-18

    ... May 2009 was published in the Federal Register (74 FR 15380-15384) on April 6, 2009. The final rule included new deflection standards, previously applicable only to automation flats, for all commercial flat... should be eligible for full-service IMb pricing. If automation prices are denied, pieces that...

  3. Focused ion beam induced deflections of freestanding thin films

    NASA Astrophysics Data System (ADS)

    Kim, Y.-R.; Chen, P.; Aziz, M. J.; Branton, D.; Vlassak, J. J.

    2006-11-01

    Prominent deflections are shown to occur in freestanding silicon nitride thin membranes when exposed to a 50keV gallium focused ion beam for ion doses between 1014 and 1017ions/cm2. Atomic force microscope topographs were used to quantify elevations on the irradiated side and corresponding depressions of comparable magnitude on the back side, thus indicating that what at first appeared to be protrusions are actually the result of membrane deflections. The shape in high-stress silicon nitride is remarkably flat-topped and differs from that in low-stress silicon nitride. Ion beam induced biaxial compressive stress generation, which is a known deformation mechanism for other amorphous materials at higher ion energies, is hypothesized to be the origin of the deflection. A continuum mechanical model based on this assumption convincingly reproduces the profiles for both low-stress and high-stress membranes and provides a family of unusual shapes that can be created by deflection of freestanding thin films under beam irradiation.

  4. Optical sensor based on a single CdS nanobelt.

    PubMed

    Li, Lei; Yang, Shuming; Han, Feng; Wang, Liangjun; Zhang, Xiaotong; Jiang, Zhuangde; Pan, Anlian

    2014-01-01

    In this paper, an optical sensor based on a cadmium sulfide (CdS) nanobelt has been developed. The CdS nanobelt was synthesized by the vapor phase transportation (VPT) method. X-Ray Diffraction (XRD) and Transmission Electron Microscopy (TEM) results revealed that the nanobelt had a hexagonal wurtzite structure of CdS and presented good crystal quality. A single nanobelt Schottky contact optical sensor was fabricated by the electron beam lithography (EBL) technique, and the device current-voltage results showed back-to-back Schottky diode characteristics. The photosensitivity, dark current and the decay time of the sensor were 4 × 10⁴, 31 ms and 0.2 pA, respectively. The high photosensitivity and the short decay time were because of the exponential dependence of photocurrent on the number of the surface charges and the configuration of the back to back Schottky junctions. PMID:24763211

  5. Light-assisted deposition of CdS thin films

    NASA Astrophysics Data System (ADS)

    Bacaksiz, E.; Novruzov, V.; Karal, H.; Yanmaz, E.; Altunbas, M.; Kopya, A. I.

    2001-11-01

    The effects of white light illumination during the deposition of CdS thin films in a quasi-closed volume on the structural, photoelectrical and optical properties are investigated. The films were highly c-axis oriented with an increasing intensity of (002) reflection as the illumination increases. The room temperature resistivity values of the CdS films decreased in the range of 107-104 Ω cm. The photosensitivity in the fundamental absorption region and the transparency in the transmission region considerably increased as the illumination increased. Under 100 mW cm-2 insolation, the efficiencies of the CdS/CdTe solar cells based on CdS window materials which were deposited: (1) in the dark; and (2) under an illumination of 150 mW cm-2 were found to be 1.8% and 7.3%, respectively.

  6. Photoelectrochemical properties of chemosynthesized CdS thin film

    NASA Astrophysics Data System (ADS)

    Pawar, S. B.; Pawar, S. A.; Bhosale, P. N.; Patil, P. S.

    2012-06-01

    Thin film of cadmium sulphide (CdS) consisting cabbage like morphology was chemically synthesized at room temperature from an aqueous alkaline bath onto soda lime glass and fluorine-doped tin oxide (FTO)-coated glass substrates. The synthesized cabbages of CdS were characterized using X-ray diffraction (XRD), UV-vis spectroscopy and scanning electron microscopy (SEM). The XRD pattern revealed the formation of CdS particles with a cubic crystal structure. SEM micrographs show that the cabbage like morphology is composed of nanopetals. Further, the photoelectochemical (PEC) performance was tested in Na2S-NaOH-S electrolyte which has maximum short circuit current of (Isc) 359μA/cm2.

  7. Tuning the Properties of Nanocrystalline CdS Thin Films

    NASA Astrophysics Data System (ADS)

    Ikhmayies, Shadia J.

    2014-01-01

    Tuning the properties of nanocrystalline cadmium sulfide (CdS) thin films is very important in the technology of photonics, detectors, and computing devices. This can be achieved through the appropriate selection of the synthesis techniques, types and concentrations of the chemicals, deposition parameters, and postdeposition heat treatments. In addition, control of the properties can be achieved by controlling the size, structure type, and surface states of the nanocrystallites without altering the chemical composition of the films. A review of the experimental methods for tuning the properties of nanocrystalline CdS thin films is performed. Although control of these variables is a complicated process, high-quality nanocrystalline CdS thin films with optimum structural, morphological, and optical properties have been produced by different authors.

  8. Eccentric superconducting RF cavity separator structure

    DOEpatents

    Aggus, John R.; Giordano, Salvatore T.; Halama, Henry J.

    1976-01-01

    Accelerator apparatus having an eccentric-shaped, iris-loaded deflecting cavity for an rf separator for a high energy high momentum, charged particle accelerator beam. In one embodiment, the deflector is superconducting, and the apparatus of this invention provides simplified machining and electron beam welding techniques. Model tests have shown that the electrical characteristics provide the desired mode splitting without adverse effects.

  9. Deflections from two types of Human Surrogates in Oblique Side Impacts

    PubMed Central

    Yoganandan, Narayan; Pintar, Frank A.

    2008-01-01

    The objective of the study was to obtain time-dependent thoracic and abdominal deflections of an anthropomorphic test device, the WorldSID dummy, in oblique impact using sled tests, and compare with post mortem human subject (PMHS) data. To simulate the oblique loading vector, the load wall was configured such that the thorax and abdominal plates were offset by twenty or thirty degrees. Deflections were obtained from a chestband placed at the middle thoracic level and five internal deflection transducers. Data were compared from the chestband and the transducer located at the same level of the thorax. In addition, data were compared with deflections from similar PMHS tests obtained using chestbands placed at the level of the axilla, xyphoid process, and tenth rib, representing the upper thorax, middle thorax, and abdominal region of the biological specimen. Peak deflections ranged from 30 to 85 mm in the dummy tests. Peak deflections ranged from 60 to 115 mm in PMHS. Under both obliquities, dummy deflection-time histories at the location along the chestband in close proximity to the internal deflection transducer demonstrated similar profiles. However, the peak deflection magnitudes from the chestband were approximately 20 mm greater than those from the internal transducer. Acknowledging that the chestband measures external deflections in contrast to the transducer which records internal ribcage deformations, peak deflections match from the two sensors. Deflection time histories were also similar between the dummy and PMHS in terms of morphology, although thoracic deflection magnitudes from the dummy matched more closely with PMHS than abdominal deflection magnitudes. The dummy deformed in such a way that peak deflections occurred along the lateral vector. This was in contrast to PMHS tests wherein maximum deflections occurred along the antero-lateral direction, suggesting differing deformation responses in the two models. In addition, peak deflections occurred

  10. CdS quantum dots in colloids and polymer matrices: electronic structure and photochemical properties

    NASA Astrophysics Data System (ADS)

    Gurin, V. S.; Artemyev, M. V.

    1994-04-01

    We have studied the optical properties and electronic structures of quantum-confined CdS particles (Q-particles, quantum dots) prepared as CdS colloids in different solvents, CdS particles embedded in polymer matrices and vacuum evaporated island films of CdS. Due to the quantum-confined effect, the optical spectra of these systems exhibit the explicit blue shift of fundamental interband absorption and the appearance of well-pronounced exciton peaks at room temperature. The electronic structure of CdS quantum dots was examined by X-ray photoeletron spectroscopy and semi-empirical quantum-chemical calculations were performed. Both XRS data and results of calculations reveal the clear difference in valence band density of states for CdS Q-particles with respect to bulk CdS. Semiconductor-like electronic structure, especially for d-band, appears for CdS clusters containing more than 100 atoms. We also compare the relative stability of CdS clusters of different structure. Additionally, we studied the photochemical properties of CdS Q-particles and observed the effect of spectral hole burning in the absorption spectra of CdS colloids in 2-propanol during UV laser irradiation. This phenomenon results probably from selective photo-oxidation of CdS Q-particles, whose exciton absorption bands are close to irradiation wavelength.

  11. Small-angle optical deflection from collinear configuration for sensitive detection in microfluidic systems.

    PubMed

    Yang, Li; Li, Xiangtang; Li, Jing; Yuan, Hongyan; Zhao, Shulin; Xiao, Dan

    2012-07-01

    This paper describes a novel detection system based on small-angle optical deflection from the collinear configuration of a microfluidic chip. In this system, the incident light beam was focused on the microchannel through the edge of a lens, resulting in a small deflection angle that deviated 20° from the collinear configuration. The emitted fluorescence was collected through the center of the same lens and delivered to a photomultiplier tube in the vertical direction; the reflection light of the chip plate was kept away from the detector. In contrast to traditional confocal and nonconfocal laser-induced fluorescence detection systems, background levels resulting from scattered excitation light, reflection and refraction from the microchip was significantly eliminated. Significant enhancement of the signal-to-noise ratio was obtained by shaping a laser beam that combined an attenuator with a spectral filter to optimize laser power and the dimensions of the laser beam. FITC and FITC-labeled amino acid were used as model analytes to demonstrate the performance sensitivity, separation efficiency, and reproducibility of this detection system by using a hybrid polydimethylsiloxane/glass microfluidic device. The limit of detection of FITC was estimated to be 2 pM (0.55 zmol) (S/N = 3). Furthermore, the single cell analysis for the determination of intracellular glutathione in a single 3T3 mouse fibroblast cell was demonstrated. The results suggest that the proposed optical arrangements will be promising for development of sensitive, low-cost microfluidic systems. PMID:22806465

  12. Compact ExB mass separator for heavy ion beams

    SciTech Connect

    Wada, M.; Hashino, T.; Hirata, F.; Kasuya, T.; Sakamoto, Y.; Nishiura, M.

    2008-02-15

    A compact ExB mass separator that deflects beam by 30 deg. has been designed and built to prove its principle of operation. The main part of the separator is contained in a shielding box of 11 cm long, 9 cm wide, and 1.5 cm high. An electromagnet of 7 cm pole diameter produced variable magnetic field in the mass separation region instead of a couple of permanent magnets which is to be used in the final design. The experimental result agreed well with the theoretical prediction, and larger mass ions is bent with less magnetic field with the aid of the deflection electric field. The reduction in resolving power for mass separation due to the deflection electric field has been investigated experimentally.

  13. The Learning Management System Evolution. CDS Spotlight Report. Research Bulletin

    ERIC Educational Resources Information Center

    Lang, Leah; Pirani, Judith A.

    2014-01-01

    This Spotlight focuses on data from the 2013 Core Data Service (CDS) to better understand how higher education institutions approach learning management systems (LMSs). Information provided for this Spotlight was derived from Module 8 of the Core Data Service, which contains several questions regarding information systems and applications.…

  14. Options for Putting CDS/ISIS Databases on the Internet

    ERIC Educational Resources Information Center

    Buxton, Andrew

    2006-01-01

    Purpose: To review the variety of software solutions available for putting CDS/ISIS databases on the internet. To help anyone considering which route to take. Design/methodology/approach: Briefly describes the characteristics, history, origin and availability of each package. Identifies the type of skills required to implement the package and the…

  15. Ultra large deflection of thin PZT/aluminium cantilever beam

    NASA Astrophysics Data System (ADS)

    Seveno, Raynald; Guiffard, Benoit; Regoin, Jean-Pierre

    2015-04-01

    Flexible piezoelectric cantilever beam has been realized by depositing lead zirconate titanate (PZT) thin film (4.5 μm) by chemical solution deposition (CSD) onto very thin aluminium foil (16 μm). The tip deflection of the beam has been measured as a function of the frequency of the applied sinusoidal voltage to the PZT film for different amplitudes. Resonance curves have been compared to a classical model of an oscillating system under sinusoidal stress with a very good agreement. Despite of weak ferroelectric properties (remnant polarization: 13 μC/cm2), ultra-large deflection amplitudes have been measured under very moderate applied voltage values: 750 μm@10 V for quasi-static mode and 5 mm@10 V at the resonance frequency ( 12 Hz), which makes this PZT/aluminium composite film very promising for highly flexible actuation applications where large displacements are wanted.

  16. Large deflection of flexible tapered functionally graded beam

    NASA Astrophysics Data System (ADS)

    Davoodinik, A. R.; Rahimi, G. H.

    2011-10-01

    In this paper the semi-analytical analyses of the flexible cantilever tapered functionally graded beam under combined inclined end loading and intermediate loading are studied. In order to derive the fully non-linear equations governing the non-linear deformation, a curvilinear coordinate system is introduced. A general non-linear second order differential equation that governs the shape of a deflected beam is derived based on the geometric nonlinearities, infinitesimal local displacements and local rotation concepts with remarkable physical properties of functionally graded materials. The solutions obtained from semi-analytical methods are numerically compared with the existing elliptic integral solution for the case of a flexible uniform cantilever functionally graded beam. The effects of taper ratio, inclined end load angle and material property gradient on large deflection of the beam are evaluated. The Adomian decomposition method will be useful toward the design of tapered functionally graded compliant mechanisms driven by smart actuators.

  17. Precise atomic mass measurements by deflection mass spectrometry

    NASA Astrophysics Data System (ADS)

    Barber, R. C.; Sharma, K. S.

    2003-05-01

    Since its inception nearly 90 years ago by J.J. Thomson, the precise determination of atomic masses by the classical technique of deflecting charged particles in electric and magnetic fields has provided a large body of data on naturally occurring nuclides. Currently, such measurements on stable nuclides have frequently achieved a precision of better than two parts in 10 9 of the mass. A review of the technique, together with a brief summary of the important historical developments in the field of precise atomic mass measurements, will be given. The more recent contributions to this field by the deflection mass spectrometer at the University of Manitoba will be provided as illustrations of the culmination of the techniques used and the applications that have been studied. A brief comparison between this and newer techniques using Penning traps will be presented.

  18. Ion Beam Deflection (AKA Push-Me/Pull-You)

    NASA Technical Reports Server (NTRS)

    Brophy, John

    2013-01-01

    The Ion Beam Deflection provides the following potential advantages over other asteroid deflection systems. Like the gravity tractor, it doesn't require despinning of the asteroid. Unlike the gravity tractor, it provides a significantly higher coupling force that is independent of the asteroid size. The concept could be tested as part of the baseline Asteroid Redirect Robotic Mission. The thrust and total impulse are entirely within the design of the SEP vehicle. The total impulse is potentially competitive with kinetic impactors and eliminates the need for a second rendezvous spacecraft.?Gridded ion thrusters provide beam divergence angles of a few degrees enabling long stand-off distances from the asteroid. Mitigating control issues. Minimizing back-sputter contamination risks

  19. Jet Deflection by Very Weak Guide Fields during Magnetic Reconnection

    SciTech Connect

    Goldman, M. V.; Newman, D. L.; Che, H.; Lapenta, G.; Markidis, S.

    2011-09-23

    Previous 2D simulations of reconnection using a standard model of initially antiparallel magnetic fields have detected electron jets outflowing from the x point into the ion outflow exhausts. Associated with these jets are extended ''outer electron diffusion regions.'' New PIC simulations with an ion to electron mass ratio as large as 1836 (an H{sup +} plasma) now show that the jets are strongly deflected and the outer electron diffusion region is broken up by a very weak out-of-plane magnetic guide field, even though the diffusion rate itself is unchanged. Jet outflow and deflection are interpreted in terms of electron dynamics and are compared to recent measurements of jets in the presence of a small guide field in Earth's magnetosheath.

  20. Deflected Mirage Mediation: A Framework for Generalized Supersymmetry Breaking

    SciTech Connect

    Kim, Ian-Woo

    2008-11-23

    We present a model of supersymmetry breaking in which the contributions from gravity/modulus, anomaly, and gauge mediation are all comparable. We term this scenario 'deflected mirage mediation', which is a generalization of the KKLT-motivated mirage mediation scenario to include gauge mediated contributions. These contributions deflect the gaugino mass unification scale and alter the pattern of soft parameters at low energies. Competitive gauge-mediated terms can naturally appear within phenomenological models based on the KKLT setup by the stabilization of the gauge singlet field responsible for the masses of the messenger fields. We analyze the renormalization group evolution of the supersymmetry breaking terms and the resulting low energy mass spectra.

  1. Pulsed photothermal deflection spectroscopy in fluid media - A review

    NASA Astrophysics Data System (ADS)

    Gupta, R.

    The fundamental principles, apparatus, and applications of photothermal deflection spectroscopy (PTDS) using pulsed lasers are examined, summarizing the results of recent theoretical and experimental investigations. The governing equations are presented and discussed, and diagrams, drawings, and graphs of typical results are provided. In one set of PTDS experiments, a flashlamp-pumped dye laser producing 1-microsec pulses of energy 2 mJ is used to pump NO2 molecules in an open N2 jet or a closed cell containing N2, and the deflection of an 800-microW HeNe laser probe beam by the pump-induced refractive-index changes is measured. The PTDS method permits determination of majority and minority species concentrations, relaxation rates, and temperature, as well as flow velocity in the case of a jet or flame.

  2. Method and apparatus for deflection measurements using eddy current effects

    NASA Technical Reports Server (NTRS)

    Chern, Engmin J. (Inventor)

    1993-01-01

    A method and apparatus for inserting and moving a sensing assembly with a mechanical positioning assembly to a desired remote location of a surface of a specimen under test and measuring angle and/or deflection by sensing the change in the impedance of at least one sensor coil located in a base plate which has a rotatable conductive plate pivotally mounted thereon so as to uncover the sensor coil(s) whose impedance changes as a function of deflection away from the center line of the base plate in response to the movement of the rotator plate when contacting the surface of the specimen under test is presented. The apparatus includes the combination of a system controller, a sensing assembly, an eddy current impedance measuring apparatus, and a mechanical positioning assembly driven by the impedance measuring apparatus to position the sensing assembly at a desired location of the specimen.

  3. MOSFET-Embedded microcantilevers for measuring deflection in biomolecular sensors.

    PubMed

    Shekhawat, Gajendra; Tark, Soo-Hyun; Dravid, Vinayak P

    2006-03-17

    A promising approach for detecting biomolecules follows their binding to immobilized probe molecules on microfabricated cantilevers; binding causes surface stresses that bend the cantilever. We measured this deflection, which is on the order of tens of nanometers, by embedding a metal-oxide semiconductor field-effect transistor (MOSFET) into the base of the cantilever and recording decreases in drain current with deflections as small as 5 nanometers. The gate region of the MOSFET responds to surface stresses and thus is embedded in silicon nitride so as to avoid direct contact with the sample solution. This approach, which offers low noise, high sensitivity, and direct readout, was used to detect specific binding events with biotin and antibodies. PMID:16456038

  4. Galvanometer deflection: a precision high-speed system.

    PubMed

    Jablonowski, D P; Raamot, J

    1976-06-01

    An X-Y galvanometer deflection system capable of high precision in a random access mode of operation is described. Beam positional information in digitized form is obtained by employing a Ronchi grating with a sophisticated optical detection scheme. This information is used in a control interface to locate the beam to the required precision. The system is characterized by high accuracy at maximum speed and is designed for operation in a variable environment, with particular attention placed on thermal insensitivity. PMID:20165203

  5. Deflection and fragmentation of near-earth asteroids

    NASA Technical Reports Server (NTRS)

    Ahrens, Thomas J.; Harris, Alan W.

    1992-01-01

    The collision with earth of near-earth asteroids or comet nuclei poses a potential threat to mankind. Objects about 100 m in diameter could be diverted from an earth-crossing trajectory by the impact of a rocket-launched mass, but for larger bodies nuclear explosions seem to be the only practical means of deflection. Fragmentation of the body by nuclear charges is less efficient or secure.

  6. Deflection and fragmentation of near-earth asteroids

    NASA Astrophysics Data System (ADS)

    Ahrens, Thomas J.; Harris, Alan W.

    1992-12-01

    The collision with earth of near-earth asteroids or comet nuclei poses a potential threat to mankind. Objects about 100 m in diameter could be diverted from an earth-crossing trajectory by the impact of a rocket-launched mass, but for larger bodies nuclear explosions seem to be the only practical means of deflection. Fragmentation of the body by nuclear charges is less efficient or secure.

  7. CdS nanoparticles/CeO2 nanorods composite with high-efficiency visible-light-driven photocatalytic activity

    NASA Astrophysics Data System (ADS)

    You, Daotong; Pan, Bao; Jiang, Fan; Zhou, Yangen; Su, Wenyue

    2016-02-01

    Different mole ratios of CdS nanoparticles (NPs)/CeO2 nanorods (NRs) composites with effective contacts were synthesized through a two-step hydrothermal method. The crystal phase, microstructure, optical absorption properties, electrochemical properties and photocatalytic H2 production activity of these composites were investigated. It was concluded that the photogenerated charge carriers in the CdS NPs/CeO2 NRs composite with a proper mole ratio (1:1) exhibited the longest lifetime and highest separation efficiency, which was responsible for the highest H2-production rate of 8.4 mmol h-1 g-1 under visible-light irradiation (λ > 420 nm). The superior photocatalytic H2 evolution properties are attributed to the transfer of visible-excited electrons of CdS NPs to CeO2 NRs, which can effectively extend the light absorption range of wide-band gap CeO2 NRs. This work provides feasible routes to develop visible-light responsive CeO2-based nanomaterial for efficient solar utilization.

  8. Application of photothermal deflection spectroscopy to electrochemical interfaces

    SciTech Connect

    Rudnicki, J.D.; McLarnon, F.R.; Cairns, E.J.

    1992-03-01

    This dissertation discusses the theory and practice of Photothermal Deflection Spectroscopy (PDS, which is also known as probe beam deflection spectroscopy, PBDS, probe deflection technique, and mirage effect spectroscopy) with respect to electrochemical systems. Much of the discussion is also relevant to non-electrochemical systems. PDS can measure the optical absorption spectrum of interfaces and concentration gradients in the electrolyte adjacent to the electrode. These measurements can be made on a wide variety of electrode surfaces and can be performed under dynamic conditions. The first three chapters discuss the theory of the phenomena that can be detected by PDS, and the equipment used in a PDS system. A secondary gradient technique'' is proposed, which places the probe beam on the back of an electrode. The results of a numerical model yield a method for determining the offset of the probe beam from the electrode surface based on the frequency response of the PDS signal. The origin and control of noise in the PDS signal are discussed. A majority of the signal noise appears to be acoustic in origin. The electrochemical oxidation of platinum is used to demonstrate that PDS has sub-monolayer sensitivity necessary to study interfacial chemistry. The results allow us to propose a two-reaction oxidation mechanism: the platinum is electrochemically oxidized to form platinum dihydroxide and dehydrated by a non-electrochemical second-order reaction. The final chapter discusses the relation of PDS to similar and competing techniques, and considers possibilities for the future of the technique.

  9. Application of photothermal deflection spectroscopy to electrochemical interfaces

    SciTech Connect

    Rudnicki, J.D.; McLarnon, F.R.; Cairns, E.J.

    1992-03-01

    This dissertation discusses the theory and practice of Photothermal Deflection Spectroscopy (PDS, which is also known as probe beam deflection spectroscopy, PBDS, probe deflection technique, and mirage effect spectroscopy) with respect to electrochemical systems. Much of the discussion is also relevant to non-electrochemical systems. PDS can measure the optical absorption spectrum of interfaces and concentration gradients in the electrolyte adjacent to the electrode. These measurements can be made on a wide variety of electrode surfaces and can be performed under dynamic conditions. The first three chapters discuss the theory of the phenomena that can be detected by PDS, and the equipment used in a PDS system. A ``secondary gradient technique`` is proposed, which places the probe beam on the back of an electrode. The results of a numerical model yield a method for determining the offset of the probe beam from the electrode surface based on the frequency response of the PDS signal. The origin and control of noise in the PDS signal are discussed. A majority of the signal noise appears to be acoustic in origin. The electrochemical oxidation of platinum is used to demonstrate that PDS has sub-monolayer sensitivity necessary to study interfacial chemistry. The results allow us to propose a two-reaction oxidation mechanism: the platinum is electrochemically oxidized to form platinum dihydroxide and dehydrated by a non-electrochemical second-order reaction. The final chapter discusses the relation of PDS to similar and competing techniques, and considers possibilities for the future of the technique.

  10. Bio-mimetic optical sensor for structural deflection measurement

    NASA Astrophysics Data System (ADS)

    Frost, Susan A.; Wright, Cameron H. G.; Streeter, Robert W.; Khan, Md. A.; Barrett, Steven F.

    2014-03-01

    Reducing the environmental impact of aviation is a primary goal of NASA aeronautics research. One approach to achieve this goal is to build lighter weight aircraft, which presents complex challenges due to a corresponding increase in structural flexibility. Wing flexibility can adversely affect aircraft performance from the perspective of aerodynamic efficiency and safety. Knowledge of the wing position during flight can aid active control methods designed to mitigate problems due to increased wing flexibility. Current approaches to measuring wing deflection, including strain measurement devices, accelerometers, or GPS solutions, and new technologies such as fiber optic strain sensors, have limitations for their practical application to flexible aircraft control. Hence, it was proposed to use a bio-mimetic optical sensor based on the fly-eye to track wing deflection in real-time. The fly-eye sensor has several advantages over conventional sensors used for this application, including light weight, low power requirements, fast computation, and a small form factor. This paper reports on the fly-eye sensor development and its application to real-time wing deflection measurement.

  11. Experimental modeling of eddy currents and deflections for tokamak limiters

    SciTech Connect

    Hua, T.Q.; Knott, M.J.; Turner, L.R.; Wehrle, R.B.

    1986-01-01

    In this study, experiments were performed to investigate deflection, current, and material stress in cantilever beams with the Fusion ELectromagnetic Induction eXperiment (FELIX) at the Argonne National Laboratory. Since structures near the plasma are typically cantilevered, the beams provide a good model for the limiter blades of a tokamak fusion reactor. The test pieces were copper, aluminum, phosphor bronze, and brass cantilever beams, clamped rigidly at one end with a nonconducting support frame inside the FELIX test volume. The primary data recorded as functions of time were the beam deflection measured with a noncontact electro-optical device, the total eddy current measured with a Rogowski coil and linking through a central hole in the beam, and the material stress extracted from strain gauges. Measurements of stress and deflection were taken at selected positions along the beam. The extent of the coupling effect depends on several factors. These include the size, the electrical and mechanical properties of the beam, segmenting of the beam, the decay rate of the dipole field, and the strength of the solenoid field.

  12. Extreme value statistics of cosmic microwave background lensing deflection angles

    NASA Astrophysics Data System (ADS)

    Merkel, Philipp M.; Schäfer, Björn Malte

    2015-10-01

    The smaller the angular scales on which the anisotropies of the cosmic microwave background (CMB) are probed the more important their distortion due to gravitational lensing becomes. Here we investigate the maxima and minima of the CMB lensing deflection field using general extreme value statistics. Since general extreme value statistics applies to uncorrelated data in first place, we consider appropriately low-pass-filtered deflection maps. Besides the suppression of correlations filtering is required for another reason: the lensing field itself is not directly observable but needs to be (statistically) reconstructed from the lensed CMB by means of a quadratic estimator. This reconstruction, though, is noise dominated and therefore requires smoothing too. In idealized Gaussian realizations as well as in realistically reconstructed data, we find that both maxima and minima of the deflection angle components follow consistently a general extreme value distribution of Weibull type. However, its shape, location and scale parameters vary significantly between different realizations. The statistics' potential power to constrain cosmological models appears, therefore, rather limited.

  13. Leaders and windshields: the art of deflecting essential information.

    PubMed

    Kerfoot, Karlene

    2004-01-01

    Do you know how much information you deflect in a day? Do you know what techniques you use to keep information at bay? We all erect windshields. It is just a matter of degree. Sometimes we deflect information in spite of our good intentions. If we are not present when people are in dialogue with us, we soon lose the attention of that person. If we are leading a meeting and the feedback begins to get uncomfortable for us, we can interject the techniques of the alpha male or alpha female, or a variety of our own. But the audience knows you are not listening, and they soon go underground with their comments and interpretations. Soon you are cut out of valuable feedback. Deflecting information by surrounding yourself with windshields just won't work. We need second and third opinions continually. One of Warren Bennis' (2002) ten traits to becoming a "tomorrow leader" is that of ensuring that the leader's boundaries are porous and permeable. In his view, leaders need the foresight to see around the corner long before others do. His belief is that the only way to do this is to be in touch with your customers, and the outside world. But that only happens when the leader's boundaries are porous and permeable so that information can seep in. Effective leaders learn to lead without windshields. PMID:15382398

  14. Leaders and windshields: the art of deflecting essential information.

    PubMed

    Kerfoot, Karlene

    2004-12-01

    Do you know how much information you deflect in a day? Do you know what techniques you use to keep information at bay? We all erect windshields. It is just a matter of degree. Sometimes we deflect information in spite of our good intentions. If we are not present when people are in dialogue with us, we soon lose the attention of that person. If we are leading a meeting and the feedback begins to get uncomfortable for us, we can interject the techniques of the alpha male or alpha female, or a variety of our own. But the audience knows you are not listening, and they soon go underground with their comments and interpretations. Soon you are cut out of valuable feedback. Deflecting information by surrounding yourself with windshields just won't work. We need second and third opinions continually. One of Warren Bennis' (2002) ten traits to becoming a "tomorrow leader" is that of ensuring that the leader's boundaries are porous and permeable. In his view, leaders need the foresight to see around the corner long before others do. His belief is that the only way to do this is to be in touch with your customers, and the outside world. But that only happens when the leader's boundaries are porous and permeable so that information can seep in. Effective leaders learn to lead without windshields. PMID:15690940

  15. Compact superconducting rf-dipole cavity designs for deflecting and crabbing applications

    SciTech Connect

    De Silva, Subashini; Delayen, Jean R.; Castilla, Alejandro

    2013-06-01

    Over the years the superconducting parallel-bar design has evolved into an rf-dipole cavity with improved properties. The new rf-dipole design is considered for a number of deflecting and crabbing applications. Some of those applications are the 499 MHz rf separator system for the Jefferson Lab 12 GeV upgrade, the 400 MHz crabbing cavity system for the proposed LHC high luminosity upgrade, and the 750 MHz crabbing cavity for the medium energy electron-ion collider in Jefferson Lab. In this paper we present the optimized rf design in terms of rf performance including rf properties, higher order modes (HOM) properties, multipacting and multipole expansion for the above mentioned applications.

  16. Effect of canard vertical location, size, and deflection on canard-wing interference at subsonic speeds

    NASA Technical Reports Server (NTRS)

    Gloss, B. B.; Ray, E. J.; Washburn, K. E.

    1978-01-01

    A generalized close-coupled canard-wing configuration was tested in a high speed 7 by 10 foot tunnel at Mach numbers of 0.40, 0.70, and 0.85 over an angle-of-attack range from -4 deg to 24 deg. Studies were made to determine the effects of canard vertical location, size, and deflection and wing leading-edge sweep on the longitudinal characteristics of the basic configuration. The two wings tested had thin symmetrical circular-arc airfoil sections with characteristically sharp leading edges swept at 60 deg and 44 deg. Two balances which allow separation of the canard-forebody contribution from the total forces and moments were used in this study.

  17. Cuspal deflection of maxillary premolars restored with bonded amalgam.

    PubMed

    el-Badrawy, W A

    1999-01-01

    The aims of this study were to measure cuspal deflection of premolars restored with bonded amalgam and to investigate bond resistance to thermo-cycling and cyclic loading. Strain gauges were used to measure cuspal deflection of maxillary premolars restored with MOD bonded amalgam restorations. A nondestructive method was used in which teeth were loaded repeatedly to record cuspal deflection following different restorative procedures. Ten extracted premolars with similar dimensions were selected and their roots mounted in resin bases 2 mm below the CEJ. Two single-element strain gauges were bonded to the buccal and lingual surfaces of the cusps of each tooth at a level that corresponded to the pulpal floor of MOD cavities. These were connected to a strain indicator with a built-in wheat-stone bridge. An Instron machine was used to apply a 100 N compressive load. Micro-strain readings were recorded with each loading at the following stages: (1) sound unprepared teeth (baseline reading), (2) following preparation of a medium-size MOD cavity, (3) 24 hours following restoration with amalgam, (4) following amalgam removal, (5) 24 hours following restoration with bonded amalgam. Durability of the bond was further tested by cyclic loading of 2000, 4000, 6000, and 8000 load cycles. Mean micro-strain values recorded at the buccal cusp were: 48.0 (21.6), 126.8(57.2), 121.4(53.3), 120.8(56.1), and 65.2(36.5) for test stages 1, 2, 3, 4, and 5 respectively. Cuspal deflections following cyclic loading recorded at the buccal cusp were: 60.0(41.0), 63.6(51.9), 59.6(36.3), and 61.6(36.8) at the above four cyclic loading stages respectively. A similar trend was also observed for measurements of the lingual cusp. It was concluded that bonding amalgam restorations decreases cuspal deflection and consequently may assist in restoring tooth strength under conditions of the oral environment. PMID:10823082

  18. Operational characteristics of a translation screen grid beam deflection system for a 5-cm Kaufman thruster

    NASA Technical Reports Server (NTRS)

    Lathem, W. C.; Hudson, W. R.

    1972-01-01

    Measurements of beam deflection angle with respect to spring positioning power and accelerator impingement current as a function of deflection angle were made on a 5-cm diameter system. Response time measurements on the translational grid beam deflection system showed that the time for the maximum deflection angle analyzed (+16.4 deg to -16.4 deg) could be reduced by a factor of nine by increasing the heating power applied to the positioning spring from 4 to 16 watts. At 14 watts the response time for maximum deflection was about 1 minute.

  19. Hole Surface Trapping Dynamics Directly Monitored by Electron Spin Manipulation in CdS Nanocrystals.

    PubMed

    Li, Xiao; Feng, Donghai; Tong, Haifang; Jia, Tianqing; Deng, Li; Sun, Zhenrong; Xu, Zhizhan

    2014-12-18

    A new detection technique, pump-spin orientation-probe ultrafast spectroscopy, is developed to study the hole trapping dynamics in colloidal CdS nanocrystals. The hole surface trapping process spatially separates the electron-hole pairs excited by the pump pulse, leaves the core negatively charged, and thus enhances the electron spin signal generated by the orientation pulse. The spin enhancement transients as a function of the pump-orientation delay reveal a fast and a slow hole trapping process with respective time constants of sub-10 ps and sub-100 ps, orders of magnitude faster than that of carrier recombination. The power dependence of hole trapping dynamics elucidates the saturation process and relative number of traps, and suggests that there are three subpopulations of nanoparticles related to hole surface trapping, one with the fast trapping pathway only, another with the slow trapping pathway only, and the third with both pathways together. PMID:26273979

  20. Unsteady aerodynamic analysis of space shuttle vehicles. Part 4: Effect of control deflections on orbiter unsteady aerodynamics

    NASA Technical Reports Server (NTRS)

    Reding, J. P.; Ericsson, L. E.

    1973-01-01

    The unsteady aerodynamics of the 040A orbiter have been explored experimentally. The results substantiate earlier predictions of the unsteady flow boundaries for a 60 deg swept delta wing at zero yaw and with no controls deflected. The test revealed a previously unknown region of discontinuous yaw characteristics at transonic speeds. Oilflow results indicate that this is the result of a coupling between wing and fuselage flows via the separated region forward of the deflected elevon. In fact, the large leeward elevon deflections are shown to produce a multitude of nonlinear stability effects which sometimes involve hysteresis. Predictions of the unsteady flow boundaries are made for the current orbiter. They should carry a good degree of confidence due to the present substantiation of previous predictions for the 040A. It is proposed that the present experiments be extended to the current configuration to define control-induced effects. Every effort should be made to account for Reynolds number, roughness, and possible hot-wall effects on any future experiments.

  1. A simplified approach to uncertainty quantification for orbits in impulsive deflection scenarios

    NASA Astrophysics Data System (ADS)

    Howley, Kirsten; Wasem, Joseph

    2014-11-01

    For the majority of near-Earth Asteroid (NEA) impact scenarios, optimal deflection strategies use a massive impactor or a nuclear explosive, either of which produce an impulsive change to the orbit of the object. However, uncertainties regarding the object composition and the efficiency of the deflection event lead to a non-negligible uncertainty in the deflection delta-velocity. Propagating this uncertainty through the resulting orbit will create a positional uncertainty envelope at the original impact epoch. We calculate a simplified analytic evolution for impulsively deflected NEAs and perform a full propagation of uncertainties that is nonlinear in the deflection delta-velocity vector. This provides an understanding of both the optimal deflection velocities needed for a given scenario, as well as the resulting positional uncertainty and corresponding residual impact probability. Confidence of a successful deflection attempt as a function of launch opportunities is also discussed for a specific case.

  2. An ECG signal processing algorithm based on removal of wave deflections in time domain.

    PubMed

    Kim, Jungkuk; Kim, Minkyu; Won, Injae; Yang, Seungyhul; Lee, Kiyoung; Huh, Woong

    2009-01-01

    This paper introduces a new approach to process biomedical signals by surgically removing wave deflections in time domain. The method first determines the epochs of high frequency deflections, cuts out them from the signal, and then connects the two disconnected points. To determine the epoch of a deflection to be removed, four slope trace waves are used to isolate the deflection based on signal characteristics of amplitude, slope, duration, and distance from neighboring deflections. The method has been applied to simulated data and MIT-BIH arrhythmia database to show its practical efficacy in the case of baseline wandering removal. It is found that the method has the capability to identify and remove high frequency deflections appropriately, leaving low frequency deflection such as baseline drifting. PMID:19963498

  3. Exciton absorption in CdS1- xSex and ZnSe1- xTex solid solutions

    NASA Astrophysics Data System (ADS)

    Naumov, A.; Permogorov, S.; Reznitsky, A.; Verbin, S.; Klochikhin, A.

    1990-04-01

    Absorption spectra of CdS1- xSex and ZnSe1- xTex semiconductor solid solutions have been studied at T = 2 K in the region of fundamental absorption edge for composition range (0.02 < x < 0.6). It is shown that potential fluctuations due to compositional disorder of the alloy have a strong effect on both the exciton state broadening and the band gap shift. A model for description of the exciton absorption spectra is developed. The contribution of the fluctuations to the part of the band gap shift which is nonlinear in concentration is separated from the other mechanisms.

  4. Stable hydrogen generation from vermiculite sensitized by CdS quantum dot photocatalytic splitting of water under visible-light irradiation.

    PubMed

    Zhang, Jian; Zhu, Wenfeng; Liu, Xiaoheng

    2014-06-28

    CdS quantum dot/vermiculite (CdS/VMT) nanocomposites have been synthesized via a facile one-step method and characterized by X-ray diffraction, UV-vis diffuse reflection spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy. The photocatalytic hydrogen generation activities of these samples were evaluated using Na2S and Na2SO3 as sacrificial reagents in water under visible-light illumination (λ ≥ 420 nm). The most important aspect of this work is the use of natural products (VMT) as host photocatalysts. The effect of CdS content on the rate of visible light photocatalytic hydrogen generation was investigated for different CdS loadings. The synergistic effect of VMT and CdS quantum dots (QDs) leads to efficient separation of the photogenerated charge carriers and, consequently, enhances the visible light photocatalytic hydrogen production activity of the photocatalyst. The CdS/VMT composite with an optimal ratio of 5% exhibits the highest hydrogen evolution rate of 92 μmol h(-1) under visible light irradiation and the highest apparent quantum efficiency of 17.7% at 420 nm. A possible photocatalytic mechanism of the CdS/VMT nanocomposite is proposed and corroborated by photoelectrochemical curves. PMID:24819860

  5. Platelike WO3 sensitized with CdS quantum dots heterostructures for photoelectrochemical dynamic sensing of H2O2 based on enzymatic etching.

    PubMed

    Wang, Yanhu; Gao, Chaomin; Ge, Shenguang; Yu, Jinghua; Yan, Mei

    2016-11-15

    A platelike tungsten trioxide (WO3) sensitized with CdS quantum dots (QDs) heterojunction is developed for solar-driven, real-time, and selective photoelectrochemical (PEC) sensing of H2O2 in the living cells. The structure is synthesized by hydrothermally growing platelike WO3 on fluorine doped tin oxide (FTO) and subsequently sensitized with CdS QDs. The as-prepared WO3-CdS QDs heterojunction achieve significant photocurrent enhancement, which is remarkably beneficial for light absorption and charge carrier separation. Based on the enzymatic etching of CdS QDs enables the activation of quenching the charge transfer efficiency, thus leading to sensitive PEC recording of H2O2 level in buffer and cellular environments. The results indicated that the proposed method will pave the way for the development of excellent PEC sensing platform with the quantum dot sensitization. This study could also provide a new train of thought on designing of self-operating photoanode in PEC sensing, promoting the application of semiconductor nanomaterials in photoelectrochemistry. PMID:27179135

  6. MoS2/CdS Nanosheets-on-Nanorod Heterostructure for Highly Efficient Photocatalytic H2 Generation under Visible Light Irradiation.

    PubMed

    Yin, Xing-Liang; Li, Lei-Lei; Jiang, Wen-Jie; Zhang, Yun; Zhang, Xiang; Wan, Li-Jun; Hu, Jin-Song

    2016-06-22

    Semiconductor-based photocatalytic H2 generation as a direct approach of converting solar energy to fuel is attractive for tackling the global energy and environmental issues but still suffers from low efficiency. Here, we report a MoS2/CdS nanohybrid as a noble-metal-free efficient visible-light driven photocatalyst, which has the unique nanosheets-on-nanorod heterostructure with partially crystalline MoS2 nanosheets intimately but discretely growing on single-crystalline CdS nanorod. This heterostructure not only facilitates the charge separation and transfer owing to the formed heterojunction, shorter radial transfer path, and fewer defects in single-crystalline nanorod, thus effectively reducing the charge recombination, but also provides plenty of active sites for hydrogen evolution reaction due to partially crystalline structure of MoS2 as well as enough room for hole extraction. As a result, the MoS2/CdS nanosheets-on-nanorod exhibits a state-of-the-art H2 evolution rate of 49.80 mmol g(-1) h(-1) and an apparent quantum yield of 41.37% at 420 nm, which is the advanced performance among all MoS2/CdS composites and CdS/noble metal photocatalysts. These findings will open opportunities for developing low-cost efficient photocatalysts for water splitting. PMID:27237623

  7. TiO2 Nanorod Arrays Sensitized with CdS Quantum Dots for Solar Cell Applications: Effects of Rod Geometry on Photoelectrochemical Performance

    NASA Astrophysics Data System (ADS)

    Zhou, Jing; Song, Bin; Zhao, Gaoling; Dong, Weixia; Han, Gaorong

    2012-05-01

    CdS quantum dot (QD) sensitized TiO2 nanorod array (NRA) film electrodes with different rod geometries were fabricated via a solvothermal route followed by a sequentialchemical bath deposition (S-CBD) process. By controlling the solution growth conditions, the rod geometries, especially the tip structures, of the TiO2 NRAs were tuned. The results indicated that the vertically aligned hierarchical NRAs possessed conically shaped tip geometry, which was favorable for film electrodes due to the reduced reflectance, enhanced light harvesting, fast charge-carrier separation and transfer, suppression of carrier recombination, sufficient electrolyte penetration and subsequent efficient QD assembly. CdS QD sensitized TiO2 NRA film electrodes with tapered tips exhibited an enhanced photoelectrochemical (PEC) performance, a photocurrent intensity of 5.13 mA/cm2 at a potential of 0 V vs. saturated calomel electrode, an open-circuit potential of -0.68 V vs. saturated calomel electrode and an incident photon to current conversion efficiency (IPCE) of 22% in the visible-light region from 400 to 500 nm. The effects of rod geometry on the optical absorption, reflectance, hydrophilic properties and PEC performance of bare TiO2 and CdS QD sensitized TiO2 NRA film electrodes were investigated. The mechanism of charge-carrier generation and transfer in these CdS QD sensitized solar cells based on vertically aligned TiO2 nanorods is discussed.

  8. Effect of Apex Flap Deflection on Vertical Tail Buffeting

    NASA Technical Reports Server (NTRS)

    Massey, Steven J.; Kandil, Osama A.

    1998-01-01

    A computational study of the effect of vortex breakdown location on vertical tail buffeting is conducted. The position of the breakdown is modified by employing an apex flap deflected by an experimentally determined optimal angle. The delayed breakdown flow and buffeting response is then compared to the nominal undeflected case. This multidisciplinary problem is solved sequentially for the fluid flow, the elastic tail deformations and the grid displacements. The fluid flow is simulated by time accurately solving the unsteady, compressible, Reynolds-averaged Navier-Stokes equations using an implicit, upwind, flux-difference splitting finite volume scheme. The elastic vibrations of the tails are modeled by uncoupled bending and torsion beam equations. These equations are solved accurately in time using the Galerkin method and a five-stage Runge-Kutta-Verner scheme. The grid for the fluid dynamics calculations is continuously deformed using interpolation functions to disperse the displacements smoothly throughout the computational domain. An angle-of-attack of 35 deg.is chosen such that the wing primary-vortex cores experience vortex breakdown and the resulting turbulent wake flow impinges on tile vertical tails. The dimensions and material properties of the vertical tails are chosen such that the deflections are large enough to insure interaction with the flow, and the natural frequencies are high enough to facilitate a practical computational solution. Results are presented for a baseline uncontrolled buffeting case and a delayed breakdown case in which the apex flap has been deflected 15 deg. The flap was found to be very effective in delaying the breakdown, increasing the location from 50%c to 94%c, which resulted in a 6% increase in lift coefficient and pitching moment. However, the integrated buffet loads and tip responses were roughly equivalent for the two cases.

  9. Deflection by kinetic impact: Sensitivity to asteroid properties

    DOE PAGESBeta

    Bruck Syal, Megan; Michael Owen, J.; Miller, Paul L.

    2016-05-01

    Impacting an asteroid with a spacecraft traveling at high speed delivers an impulsive change in velocity to the body. In certain circumstances, this strategy could be used to deflect a hazardous asteroid, moving its orbital path off of an Earth-impacting course. However, the efficacy of momentum delivery to asteroids by hypervelocity impact is sensitive to both the impact conditions (particularly velocity) and specific characteristics of the target asteroid. We numerically model asteroid response to kinetic impactors under a wide range of initial conditions, using an Adaptive Smoothed Particle Hydrodynamics code. Impact velocities spanning 1–30 km/s were investigated, yielding, for amore » particular set of assumptions about the modeled target material, a power-law dependence consistent with a velocity-scaling exponent of μ = 0.44. Target characteristics including equation of state, strength model, porosity, rotational state, and shape were varied, and corresponding changes in asteroid response were documented. Moreover, the kinetic-impact momentum-multiplication factor, β, decreases with increasing asteroid cohesion and increasing porosity. Although increased porosity lowers β, larger porosities result in greater deflection velocities, as a consequence of reduced target masses for asteroids of fixed size. Porosity also lowers disruption risk for kinetic impacts near the threshold of disruption. Including fast (P = 2.5 h) and very fast (P = 100 s) rotation did not significantly alter β but did affect the risk of disruption by the impact event. Asteroid shape is found to influence the efficiency of momentum delivery, as local slope conditions can change the orientation of the crater ejecta momentum vector. Our results emphasize the need for asteroid characterization studies to bracket the range of target conditions expected at near-Earth asteroids while also highlighting some of the principal uncertainties associated with the kinetic-impact deflection

  10. Deflection by kinetic impact: Sensitivity to asteroid properties

    NASA Astrophysics Data System (ADS)

    Bruck Syal, Megan; Michael Owen, J.; Miller, Paul L.

    2016-05-01

    Impacting an asteroid with a spacecraft traveling at high speed delivers an impulsive change in velocity to the body. In certain circumstances, this strategy could be used to deflect a hazardous asteroid, moving its orbital path off of an Earth-impacting course. However, the efficacy of momentum delivery to asteroids by hypervelocity impact is sensitive to both the impact conditions (particularly velocity) and specific characteristics of the target asteroid. Here we numerically model asteroid response to kinetic impactors under a wide range of initial conditions, using an Adaptive Smoothed Particle Hydrodynamics code. Impact velocities spanning 1-30 km/s were investigated, yielding, for a particular set of assumptions about the modeled target material, a power-law dependence consistent with a velocity-scaling exponent of μ = 0.44. Target characteristics including equation of state, strength model, porosity, rotational state, and shape were varied, and corresponding changes in asteroid response were documented. The kinetic-impact momentum-multiplication factor, β, decreases with increasing asteroid cohesion and increasing porosity. Although increased porosity lowers β, larger porosities result in greater deflection velocities, as a consequence of reduced target masses for asteroids of fixed size. Porosity also lowers disruption risk for kinetic impacts near the threshold of disruption. Including fast (P = 2.5 h) and very fast (P = 100 s) rotation did not significantly alter β but did affect the risk of disruption by the impact event. Asteroid shape is found to influence the efficiency of momentum delivery, as local slope conditions can change the orientation of the crater ejecta momentum vector. These results emphasize the need for asteroid characterization studies to bracket the range of target conditions expected at near-Earth asteroids while also highlighting some of the principal uncertainties associated with the kinetic-impact deflection strategy.

  11. Electrochemical biosensor based on CdS nanostructure surfaces.

    PubMed

    Qian, Jiqing; Yan, Shancheng; Xiao, Zhongdang

    2012-01-15

    Well-defined hexangularly faced CdS nanorod arrays have been grown directly on a conductive ITO glass via a facile one-step and non-template hydrothermal approach. Gold nanoparticles were decorated onto the nanorods to enhance the electron transfer process of electrode. Glucose oxidase (GOD) was then immobilized on the CdS through crosslinking with chitosan (CS), which resulted in a glucose biosensor with high enzyme loading and excellent sensitivity. Such a chitosan-encapsulated GOD-based biosensor revealed a relatively rapid response time of less than 50s, and an approximate linear detection range of glucose concentration, from 50 to 500 μmol L(-1) with a detection limit of 38 μmol L(-1) and an electrode sensitivity of 5.9 μA mM(-1). PMID:22018624

  12. Self-referenced prism deflection measurement schemes with microradian precision

    SciTech Connect

    Olson, Rebecca; Paul, Justin; Bergeson, Scott; Durfee, Dallin S

    2005-08-01

    We have demonstrated several inexpensive methods that can be used to measure the deflection angles of prisms with microradian precision. The methods are self-referenced, where various reversals are used to achieve absolute measurements without the need of a reference prism or any expensive precision components other than the prisms under test. These techniques are based on laser interferometry and have been used in our laboratory to characterize parallel-plate beam splitters, penta prisms, right-angle prisms, and corner cube reflectors using only components typically available in an optics laboratory.

  13. Deflected Mirage Mediation: A Phenomenological Framework for Generalized Supersymmetry Breaking

    SciTech Connect

    Everett, Lisa L.; Kim, Ian-Woo; Ouyang, Peter; Zurek, Kathryn M.

    2008-09-05

    We present a general phenomenological framework for dialing between gravity mediation, gauge mediation, and anomaly mediation. The approach is motivated from recent developments in moduli stabilization, which suggest that gravity mediated terms can be effectively loop suppressed and thus comparable to gauge and anomaly mediated terms. The gauginos exhibit a mirage unification behavior at a ''deflected'' scale, and gluinos are often the lightest colored sparticles. The approach provides a rich setting in which to explore generalized supersymmetry breaking at the CERN Large Hadron Collider.

  14. Transit time spreads in biased paracentric hemispherical deflection analyzers

    NASA Astrophysics Data System (ADS)

    Sise, Omer; Zouros, Theo J. M.

    2016-02-01

    The biased paracentric hemispherical deflection analyzers (HDAs) are an alternative to conventional (centric) HDAs maintaining greater dispersion, lower angular aberrations, and hence better energy resolution without the use of any additional fringing field correctors. In the present work, the transit time spread of the biased paracentric HDA is computed over a wide range of analyzer parameters. The combination of high energy resolution with good time resolution and simplicity of design makes the biased paracentric analyzers very promising for both coincidence and singles spectroscopy applications.

  15. Frequency response of optical beam deflection by ultrasound in water.

    PubMed

    Caron, James N; DiComo, Greg P

    2014-11-10

    Acoustic waveforms create fluctuations in the index of refraction of the medium. An optical beam passing through the disturbance will be deflected or displaced from the original path. The acoustic wave can be detected by sending a laser through the disturbance and sensing the path changes of the beam with a position-sensitive photodetector. This paper presents a model of this interaction in water to predict the sensitivity and frequency response. The model demonstrates that the frequency response of the system is broadband, allowing detection from a few hundred hertz to 20 MHz. This technique has potential use for underwater acoustic sensing and ultrasonic inspection of materials. PMID:25402989

  16. Force feedback microscopy based on an optical beam deflection scheme

    NASA Astrophysics Data System (ADS)

    Vitorino, Miguel V.; Carpentier, Simon; Costa, Luca; Rodrigues, Mario S.

    2014-07-01

    Force feedback microscopy circumvents the jump to contact in atomic force microscopy when using soft cantilevers and quantitatively measures the interaction properties at the nanoscale by simultaneously providing force, force gradient, and dissipation. The force feedback microscope developed so far used an optical cavity to measure the tip displacement. In this Letter, we show that the more conventional optical beam deflection scheme can be used to the same purpose. With this instrument, we have followed the evolution of the Brownian motion of the tip under the influence of a water bridge.

  17. Controlling plume deflection by acoustic excitation - An experimental demonstration

    NASA Astrophysics Data System (ADS)

    Ahuja, K. K.

    1990-10-01

    Effect of imposing an external sound field on a Coanda jet was investigated experimentally. It was found that the exhaust angle of a Coanda plume can be varied by changing the level of excitation. Limited experiments were also performed in a wind tunnel to study the effects of flight simulation on plume deflection controllability by sound using a hollow airfoil fitted with a Coanda jet. Pressure coefficients are measured over this airfoil with and without acoustic excitation of the Coanda Jet. This exploratory study provided a number of new ideas for future work for controlling flow over curved surfaces.

  18. Force feedback microscopy based on an optical beam deflection scheme

    SciTech Connect

    Vitorino, Miguel V.; Rodrigues, Mario S.; Carpentier, Simon; Costa, Luca

    2014-07-07

    Force feedback microscopy circumvents the jump to contact in atomic force microscopy when using soft cantilevers and quantitatively measures the interaction properties at the nanoscale by simultaneously providing force, force gradient, and dissipation. The force feedback microscope developed so far used an optical cavity to measure the tip displacement. In this Letter, we show that the more conventional optical beam deflection scheme can be used to the same purpose. With this instrument, we have followed the evolution of the Brownian motion of the tip under the influence of a water bridge.

  19. Skew deflection of magnetic vortices in a field gradient

    NASA Astrophysics Data System (ADS)

    Papanicolaou, N.

    1994-07-01

    Magnetic vortices with a nonvanishing winding number, the strictly two-dimensional analogs of realistic magnetic bubbles, are studied within the isotropic Heisenberg model. In particular, we present a numerical simulation of their dynamics under the influence of an applied magnetic field gradient. In addition to verifying some known theoretical results concerning the gross features of skew deflection, in analogy with the Hall motion of an electron, we are able to exhibit some important details of the dynamics of the vortex around its guiding center.

  20. Cue and ball deflection (or ``squirt'') in billiards

    NASA Astrophysics Data System (ADS)

    Cross, Rod

    2008-03-01

    A billiard ball struck by a cue travels in the same direction as the cue unless the ball is struck toward one side in order to impart sidespin. In that case the ball deflects or "squirts" away from the line of approach of the cue, typically by a few degrees. Measurements and calculations are presented showing how a cue tip slides across the ball if it is unchalked, resulting in a large squirt angle, and how it grips the ball when it is chalked, resulting in a smaller squirt angle.

  1. Photoconductivity of CdS under high pressure

    NASA Astrophysics Data System (ADS)

    Savić, Pavle; Urošević, Vladeta

    1987-04-01

    The photoconductivity of the high-pressure (rocksalt) phase of CdS has been investigated over the 30-120 kbar pressure range. A decrease of the photo-threshold from 1.60 eV (at 30 kbar) to 1.49 eV (at 120 kbar) indicates an indirect gap semiconductor. The values obtained have been compared with the Savić-Kašanin theory.

  2. A simple route to shape controlled CdS nanoparticles

    NASA Astrophysics Data System (ADS)

    Nejo, Ayorinde O.; Nejo, Adeola A.; Pullabhotla, Rajasekhar V. S. R.; Revaprasadu, Neerish

    2013-02-01

    We report the synthesis of CdS nanoparticles in the form of spheres, triangles and wire-like structures. The method involves the reaction of reduced sulfur with a cadmium salt followed by thermolysis in hexadecylamine (HDA). The different shapes were obtained by variation of reaction conditions such as reaction time, temperature and cadmium source. The optical studies show the particles to be quantum confined and luminescent at room temperature.

  3. Preliminary Results from Coordinated UVCS-CDS-Ulysses Observations

    NASA Technical Reports Server (NTRS)

    Parenti, S.; Bromage, B. J.; Poletto, G.; Suess, S. T.; Raymond, J. C.; Noci, G.; Bromage, G. E.; Rose, M. Franklin (Technical Monitor)

    2001-01-01

    The June 2000 quadrature between the Sun, Earth, and Ulysses took place with Ulysses at a distance of 3.35 AU from the Sun and at heliocentric latitude 58.2 deg south, in the southeast quadrant. This provided an opportunity to observe the corona close to the Sun with Coronal Diagnostic Spectrometer (CDS) and Ultraviolet Coronograph Spectrometer (UVCS) and, subsequently, to sample the same plasma when it reached Ulysses. Here we focus on simultaneous observations of UVCS and CDS made on June 12, 13, 16 and 17. The UVCS data were acquired at heliocentric altitudes ranging from 1.6 to 2.2 solar radii, using different grating positions, in order to get a wide wavelength range. CDS data consisted of Normal Incidence Spectrometer (NIS) full wavelength rasters of 120" x 150" centered at altitudes up to 1.18 solar radii, together with Grazing Incidence Spectrometer (GIS) 4" x 4" rasters within the same field of view, out to 1.2 solar radii. The radial direction to Ulysses passed through a high latitude streamer, throughout the 4 days of observations, Analysis of the spectra taken by UVCS shows a variation of the element abundances in the streamer over our observing interval: however, because the observations were in slightly different parts of the streamer on different days, the variation could be ascribed either to a temporal or spatial effect. The oxygen abundance, however, seems to increase at the edge of the streamer, as indicated by previous analyses. This suggests the variation may be a function of position within the streamer, rather than a temporal effect. Oxygen abundances measured by SWICS on Ulysses are compared with the CDS and UVCS results to see whether changes measured in situ follow the same pattern.

  4. Photothermal beam deflection applied to SO2 trace detection

    NASA Astrophysics Data System (ADS)

    Manzano, Francisco A.; D'Accurso, V.; Radulovich, O.

    2004-10-01

    We present the application to environmental monitoring of a compact setup for in situ trace gas detection based on photothermal beam deflection (mirage effect) spectroscopy. Gas traces measurements are performed by detecting the time-varying component of the photothermal deflection of a red diode laser beam, propagating inside the region where a pollutant is excited by another laser. In this work, detection of traces of SO2 in a mixture with Nitrogen at atmospheric pressure enclosed in a glass cell, was performed using the fourth-harmonic pulses of a 10 Hz Nd:YAG laser. It was verified by FTIR spectroscopy that negligible SO2 destruction was produced after irradiation of high pressure mixtures with 105 UV pulses. Several beam sizes and propagating angles for the UV and visible laser were tested and evaluated in order to overcome parasitic signals due to unwanted absorption in optical elements. With this setup we reached a detection limit of 5 ppbV in a hundred-second averaging time span but we estimate sub-ppbV levels can be reached by simple changes in the geometry for improving the signal to noise ratio.

  5. Design and Field Test of a Galvanometer Deflected Streak Camera

    SciTech Connect

    Lai, C C; Goosman, D R; Wade, J T; Avara, R

    2002-11-08

    We have developed a compact fieldable optically-deflected streak camera first reported in the 20th HSPP Congress. Using a triggerable galvanometer that scans the optical signal, the imaging and streaking function is an all-optical process without incurring any photon-electron-photon conversion or photoelectronic deflection. As such, the achievable imaging quality is limited mainly only by optical design, rather than by multiple conversions of signal carrier and high voltage electron-optics effect. All core elements of the camera are packaged into a 12 inch x 24 inch footprint box, a size similar to that of a conventional electronic streak camera. At LLNL's Site-300 Test Site, we have conducted a Fabry-Perot interferometer measurement of fast object velocity using this all-optical camera side-by-side with an intensified electronic streak camera. These two cameras are configured as two independent instruments for recording synchronously each branch of the 50/50 splits from one incoming signal. Given the same signal characteristics, the test result has undisputedly demonstrated superior imaging performance for the all-optical streak camera. It produces higher signal sensitivity, wider linear dynamic range, better spatial contrast, finer temporal resolution, and larger data capacity as compared with that of the electronic counterpart. The camera had also demonstrated its structural robustness and functional consistence to be well compatible with field environment. This paper presents the camera design and the test results in both pictorial records and post-process graphic summaries.

  6. Landscape of supersymmetric particle mass hierarchies in deflected mirage mediation

    NASA Astrophysics Data System (ADS)

    Altunkaynak, B.; Nelson, B. D.; Everett, L. L.; Rao, Y.; Kim, I.-W.

    2012-01-01

    With the aim of uncovering viable regions of parameter space in deflected mirage mediation (DMM) models of supersymmetry breaking, we study the landscape of particle mass hierarchies for the lightest four non-Standard Model states for DMM models and compare the results to that of minimal supergravity/constrained MSSM (mSUGRA/CMSSM) models, building on previous studies of Feldman, Liu, and Nath. Deflected mirage mediation is a string-motivated scenario in which the soft terms include comparable contributions from gravity mediation, gauge mediation, and anomaly mediation. DMM allows a wide variety of phenomenologically preferred models with light charginos and neutralinos, including novel patterns in which the heavy Higgs particles are lighter than the lightest superpartner. We use this analysis to motivate two DMM benchmark points to be used for more detailed collider studies. One model point has a higgsino-dominated lightest superpartner and a compressed yet heavy spectrum, while the other has a stau NLSP and similar features to mSUGRA/CMSSM models, but with a slightly less stretched spectrum.

  7. Deflection of Resilient Materials for Reduction of Floor Impact Sound

    PubMed Central

    Lee, Jung-Yoon; Kim, Jong-Mun

    2014-01-01

    Recently, many residents living in apartment buildings in Korea have been bothered by noise coming from the houses above. In order to reduce noise pollution, communities are increasingly imposing bylaws, including the limitation of floor impact sound, minimum thickness of floors, and floor soundproofing solutions. This research effort focused specifically on the deflection of resilient materials in the floor sound insulation systems of apartment houses. The experimental program involved conducting twenty-seven material tests and ten sound insulation floating concrete floor specimens. Two main parameters were considered in the experimental investigation: the seven types of resilient materials and the location of the loading point. The structural behavior of sound insulation floor floating was predicted using the Winkler method. The experimental and analytical results indicated that the cracking strength of the floating concrete floor significantly increased with increasing the tangent modulus of resilient material. The deflection of the floating concrete floor loaded at the side of the specimen was much greater than that of the floating concrete floor loaded at the center of the specimen. The Winkler model considering the effect of modulus of resilient materials was able to accurately predict the cracking strength of the floating concrete floor. PMID:25574491

  8. Effects of asteroid rotation on directed energy deflection

    NASA Astrophysics Data System (ADS)

    Johansson, Isabella E.; Tsareva, Tatiana; Griswold, Janelle; Lubin, Philip; Hughes, Gary B.; O'Neill, Hugh; Meinhold, Peter; Suen, Jonathan; Zhang, Qicheng; Riley, Jordan; Melis, Carl; Walsh, Kevin; Brashears, Travis; Bollag, Justin; Mathew, Shana; Bible, Johanna

    2014-09-01

    Asteroids that threaten Earth could be deflected from their orbits using laser directed energy or concentrated solar energy to vaporize the surface; the ejected plume would create a reaction thrust that pushes the object away from its collision course with Earth. One concern regarding directed energy deflection approaches is that asteroids rotate as they orbit the Sun. Asteroid rotation reduces the average thrust and changes the thrust vector imparting a time profile to the thrust. A directed energy system must deliver sufficient flux to evaporate surface material even when the asteroid is rotating. Required flux levels depend on surface material composition and albedo, thermal and bulk mechanical properties of the asteroid, and asteroid rotation rate. In the present work we present results of simulations for directed energy ejecta-plume asteroid threat mitigation. We use the observed distribution of asteroid rotational rates, along with a range of material and mechanical properties, as input to a thermal-physical model of plume generation. We calculate the expected thrust profile for rotating objects. Standoff directed energy schemes that deliver at least 10 MW/m2 generate significant thrust for all but the highest conceivable rotation rates.

  9. Deflection of resilient materials for reduction of floor impact sound.

    PubMed

    Lee, Jung-Yoon; Kim, Jong-Mun

    2014-01-01

    Recently, many residents living in apartment buildings in Korea have been bothered by noise coming from the houses above. In order to reduce noise pollution, communities are increasingly imposing bylaws, including the limitation of floor impact sound, minimum thickness of floors, and floor soundproofing solutions. This research effort focused specifically on the deflection of resilient materials in the floor sound insulation systems of apartment houses. The experimental program involved conducting twenty-seven material tests and ten sound insulation floating concrete floor specimens. Two main parameters were considered in the experimental investigation: the seven types of resilient materials and the location of the loading point. The structural behavior of sound insulation floor floating was predicted using the Winkler method. The experimental and analytical results indicated that the cracking strength of the floating concrete floor significantly increased with increasing the tangent modulus of resilient material. The deflection of the floating concrete floor loaded at the side of the specimen was much greater than that of the floating concrete floor loaded at the center of the specimen. The Winkler model considering the effect of modulus of resilient materials was able to accurately predict the cracking strength of the floating concrete floor. PMID:25574491

  10. Mirage models confront the LHC. III. Deflected mirage mediation

    NASA Astrophysics Data System (ADS)

    Everett, Lisa L.; Garon, Todd; Kaufman, Bryan L.; Nelson, Brent D.

    2016-03-01

    We complete the study of a class of string-motivated effective supergravity theories in which modulus-induced soft supersymmetry breaking is sufficiently suppressed in the observable sector so as to be competitive with anomaly-mediated supersymmetry breaking. Here we consider deflected "mirage mediation" (DMM), where contributions from gauge mediation are added to those arising from gravity mediation and anomaly mediation. We update previous work that surveyed the rich parameter space of such theories, in light of data from the CERN Large Hadron Collider (LHC) and recent dark matter detection experiments. Constraints arising from LHC superpartner searches at √{s }=8 TeV are considered, and discovery prospects at √{s }=14 TeV are evaluated. We find that deflected mirage mediation generally allows for S U (3 )-charged superpartners of significantly lower mass (given current knowledge of the Higgs mass and neutralino relic density) than was found for the "pure" mirage mediation models of Kachru et al. [Phys. Rev. D 68, 046005 (2003)]. Consequently, discovery prospects are enhanced for many combinations of matter multiplet modular weights. We examine the experimental challenges that will arise due to the prospect of highly compressed spectra in DMM, and the correlation between accessibility at the LHC and discovery prospects at large-scale liquid xenon dark matter detectors.

  11. Photodeposition of Pt on Colloidal CdS and CdSe/CdS Semiconductor Nanostructures

    SciTech Connect

    Dukovic, Gordana; Merkle, Maxwell G.; Nelson, James H.; Hughes, Steven M.; Alivisatos, A. Paul

    2008-08-06

    Semiconductor photocatalysis has been identified as a promising avenue for the conversion of solar energy into environmentally friendly fuels, most notably by the production of hydrogen from water.[1-5] Nanometer-scale materials in particular have attracted considerable scientific attention as the building blocks for light-harvesting applications.[6,7] Their desirable attributes include tunability of the optical properties with size, amenability to relatively inexpensive low-temperature processing, and a high degree of synthetic sophistication leading to increasingly complex and multi-functional architectures. For photocatalysis in particular, the high surface-to-volume ratios in nanoscale materials should lead to an increased availability of carriers for redox reactions on the nanoparticle surface. Recombination of photoexcited carriers directly competes with photocatalytic activity.[3] Charge separation is often achieved with multi-component heterostructures. An early example is the case of TiO2 powders functionalized with Pt and RuO2 particles, where photoexcited electrons are transferred to Pt (the reduction site) and holes to RuO2 (the oxidation site).[8] More recently, many colloidally synthesized nanometer-scale metal-semiconductor heterostructures have been reported.[7,9,10] A majority of these structures are made by thermal methods.[7,10] We have chosen to study photochemical formation of metal-semiconductor heterostructures. The detailed understanding of the mechanisms involved in photodeposition of metals on nanometer-scale semiconductors is necessary to enable a high degree of synthetic control. At the same time, because the results of metal deposition can be directly observed by electron microscopy, it can be used to understand how factors such as nanocrystal composition, shape, carrier dynamics, and surface chemistry influence the photochemical properties of semiconductor nanocrystals. In this communication, we report on the photodeposition of Pt on

  12. Extracellular Synthesis of Luminescent CdS Quantum Dots Using Plant Cell Culture

    NASA Astrophysics Data System (ADS)

    Borovaya, Mariya N.; Burlaka, Olga M.; Naumenko, Antonina P.; Blume, Yaroslav B.; Yemets, Alla I.

    2016-02-01

    The present study describes a novel method for preparation of water-soluble CdS quantum dots, using bright yellow-2 (BY-2) cell suspension culture. Acting as a stabilizing and capping agent, the suspension cell culture mediates the formation of CdS nanoparticles. These semiconductor nanoparticles were determined by means of an UV-visible spectrophotometer, photoluminescence, high-resolution transmission electron microscopy (HRTEM), and XRD. Followed by the electron diffraction analysis of a selected area, transmission electron microscopy indicated the formation of spherical, crystalline CdS ranging in diameter from 3 to 7 nm and showed wurtzite CdS quantum dots. In the present work, the toxic effect of synthesized CdS quantum dots on Nicotiana tabacum protoplasts as a very sensitive model was under study. The results of this research revealed that biologically synthesized CdS nanoparticles in low concentrations did not induce any toxic effects.

  13. Optical Properties of CdS Nanobelts and Nanosaws Synthesized by Thermal Evaporation Method

    NASA Astrophysics Data System (ADS)

    Peng, Zhi-wei; Zou, Bing-suo

    2012-04-01

    By a simple one-step H2-assisted thermal evaporation method, high quality CdS nanostructures have been successfully fabricated on Au coated Si substrates in large scale. The as-synthesized CdS nanostructures consisted of sword-like nanobelts and toothed nanosaws with a single-crystal hexagonal wurtzite structure. The deposition temperature played an important role in determining the size and morphology of the CdS nanostructures. A combination of vapor-liquid-solid and vapor-solid growth mechanisms were proposed to interpret the formation of CdS nanostructures. Photoluminescence measurement indicated that the nanobelts and nanosaws have a prominent green emission at about 512 nm, which is the band-to-band emission of CdS. The waveguide characteristics of both types of CdS nanostructures were observed and discussed.

  14. Extracellular Synthesis of Luminescent CdS Quantum Dots Using Plant Cell Culture.

    PubMed

    Borovaya, Mariya N; Burlaka, Olga M; Naumenko, Antonina P; Blume, Yaroslav B; Yemets, Alla I

    2016-12-01

    The present study describes a novel method for preparation of water-soluble CdS quantum dots, using bright yellow-2 (BY-2) cell suspension culture. Acting as a stabilizing and capping agent, the suspension cell culture mediates the formation of CdS nanoparticles. These semiconductor nanoparticles were determined by means of an UV-visible spectrophotometer, photoluminescence, high-resolution transmission electron microscopy (HRTEM), and XRD. Followed by the electron diffraction analysis of a selected area, transmission electron microscopy indicated the formation of spherical, crystalline CdS ranging in diameter from 3 to 7 nm and showed wurtzite CdS quantum dots. In the present work, the toxic effect of synthesized CdS quantum dots on Nicotiana tabacum protoplasts as a very sensitive model was under study. The results of this research revealed that biologically synthesized CdS nanoparticles in low concentrations did not induce any toxic effects. PMID:26909780

  15. Photo current generation in RGO - CdS nanorod thin film device

    NASA Astrophysics Data System (ADS)

    Chakraborty, Koushik; Chakrabarty, Sankalpita; Ibrahim, Sk.; Pal, Tanusri; Ghosh, Surajit

    2016-05-01

    Herein, we report the synthesis and characterization of reduced graphene oxide (RGO) - cadmium sulfide (CdS) nanocomposite materials. The reduction of GO, formation of CdS and decoration of CdS onto RGO sheets were done in a one- pot solvothermal process. We have observed that the PL intensity for CdS nanorods remarkably quenched after the attachment of RGO, which established the photo induced charge transformation from the CdS nanorod to RGO sheets through the RGO-CdS interface. The optoelectronic transport properties of our fabricated large area thin film device exhibits excellent photo induced charge generation under simulated solar light illumination. The photo sensitivity of the device increases linearly with the increase of illuminated light intensity. The RGO-CdS composite exhibits enhance photocatalytic dye degradation efficiency in compare to control CdS under simulated solar light illumination.

  16. Development of low noise cantilever deflection sensor for multienvironment frequency-modulation atomic force microscopy

    SciTech Connect

    Fukuma, Takeshi; Kimura, Masayuki; Kobayashi, Kei; Matsushige, Kazumi; Yamada, Hirofumi

    2005-05-15

    We have developed a low noise cantilever deflection sensor with a deflection noise density of 17 fm/{radical}(Hz) by optimizing the parameters used in optical beam deflection (OBD) method. Using this sensor, we have developed a multienvironment frequency-modulation atomic force microscope (FM-AFM) that can achieve true molecular resolution in various environments such as in moderate vacuum, air, and liquid. The low noise characteristic of the deflection sensor makes it possible to obtain a maximum frequency sensitivity limited by the thermal Brownian motion of the cantilever in every environment. In this paper, the major noise sources in OBD method are discussed in both theoretical and experimental aspects. The excellent noise performance of the deflection sensor is demonstrated in deflection and frequency measurements. True molecular-resolution FM-AFM images of a polydiacetylene single crystal taken in vacuum, air, and water are presented.

  17. Photocatalytic metal-organic framework from CdS quantum dot incubated luminescent metallohydrogel.

    PubMed

    Saha, Subhadeep; Das, Gobinda; Thote, Jayshri; Banerjee, Rahul

    2014-10-22

    Cadmium sulfide (CdS) quantum dots (<10 nm in size) have been successfully synthesized in situ without any capping agent in a Zn(II)-based low-molecular-weight metallohydrogel (ZAVA). Pristine ZAVA hydrogel shows blue luminescence, but the emission can be tuned upon encapsulation of the CdS quantum dots. Time-dependent tunable emission (white to yellow to orange) of the CdS incubated gel (CdS@ZAVA gel) can be attributed to sluggish growth of the quantum dots inside the gel matrix. Once CdS quantum dots are entrapped, their augmentation can be stopped by converting the gel into xerogel, wherein the quantum dots remains embedded in the solid xerogel matrix. Similar size stabilization of CdS quantum dots can be achieved by means of a unique room-temperature conversion of the CdS incubated ZAVA gel to CdS incubated MOF (CdS@ZAVCl) crystals. This in turn arrests the tunability in emission owing to the restriction in the growth of CdS quantum dots inside xerogel and MOF. These CdS embedded MOFs have been utilized as a catalyst for water splitting under visible light. PMID:25279940

  18. Electrical conductivity of single CdS nanowire synthesized by aqueous chemical growth

    NASA Astrophysics Data System (ADS)

    Long, Yunze; Chen, Zhaojia; Wang, Wenlong; Bai, Fenglian; Jin, Aizi; Gu, Changzhi

    2005-04-01

    In this Letter, we report on the temperature-dependent conductivity and current-voltage curve of a single CdS nanowire, which was synthesized by a simple aqueous chemical growth method. A pair of platinum microleads was fabricated on the single CdS nanowire by focused ion-beam deposition. The room-temperature conductivity and the band gap of the single CdS wire are 0.82Ω-1cm-1 and 0.055eV, respectively. When the applied electric field is larger than 1090Vcm-1, the CdS nanowire shows a nonlinear I-V curve at room temperature.

  19. A Deflection test of General Relativity Using the FAME Data

    NASA Astrophysics Data System (ADS)

    Reasenberg, R. D.

    2000-05-01

    The deflection of light by the Sun provides one of the classical tests of general relativity. The deflection is closely related to the Shapiro time delay and, in the context of the PPN formalism, each has an overall coefficient of (1 + γ ) / 2. The current published set of strong determinations of the PPN parameter γ are based on Viking radio delay (Reasenberg et al., 1979, ApJL: 1.000 +- 0.002), VLBI data intended for geodesy (Robertson et al., 1991, Nature: 1.0002 +- 0.002), VLBI data for relativity (Lebach et al., 1995, Phys. Rev. Lett: 0.9996 +- 0.0016), and Hipparcos (Froeschle et al., 1997, ESA SP-402: 0.997 +- 0.003). FAME will observe 40 million stars about 1000 times each during a 2.5 year mission, and a 2.5 year extended mission is planned. For V-mag = 9, its nominal measurement accuracy is 1.1 mas along the great circle defined by the spin direction, which remains about 45 deg from the Sun direction as it precesses around the Sun. Although FAME observations are made as close as 45 deg from the Sun, those have zero sensitivity because they are made in the wrong direction. At 90 deg from the Sun, the deflection seen from Earth is 4.1 mas, which would yield a SNR of 3.7 for FAME, were it not for the ``cosine term." The most sensitive measurements are made when the spacecraft has rotated the view port 45 deg from the observations closest to the Sun -- Sun-star angle of 60 deg -- yielding a single-measurement SNR of 4. A preliminary propagation-of-error analysis shows that a 2.5 year FAME mission has the sensitivity to measure γ with an uncertainty of 3.4 10-5, using all stars from V-mag 5 to 15. However, as was the case for Hipparcos, correlations and systematic errors will result in a larger uncertainty, perhaps 3 to 10 fold larger. This work has been supported by the Smithsonian Astrophysical Observatory. FAME is a NASA MIDEX mission with the PI at the U.S. Naval Observatory.

  20. Orthogonally interdigitated shielded serpentine travelling wave cathode ray tube deflection structure

    DOEpatents

    Hagen, Edward C.; Hudson, Charles L.

    1995-01-01

    A new deflection structure (12) which deflects a beam of charged particles, uch as an electron beam (15), includes a serpentine set (20) for transmitting a deflection field, and a shielding frame (25) for housing the serpentine set (20). The serpentine set (20) includes a vertical serpentine deflection element (22) and a horizontal serpentine deflection element (24). These deflection elements (22, 24) are identical, and are interdigitatedly and orthogonally disposed relative to each other, for forming a central transmission passage (75), through which the electron beam (15) passes, and is deflected by the deflection field, so as to minimize drift space signal distortion. The shielding frame (25) includes a plurality of ground blocks (26, 28, 30, 32), and forms an internal serpentine trough (77) within these ground blocks, for housing the serpentine set (20). The deflection structure (12) further includes a plurality of feedthrough connectors (35, 37, 35I, 37I), which are inserted through the shielding frame (25), and which are electrically connected to the serpentine set (20).

  1. Calibrating laser beam deflection systems for use in atomic force microscopes and cantilever sensors

    SciTech Connect

    Beaulieu, L.Y.; Godin, Michel; Laroche, Olivier; Tabard-Cossa, Vincent; Gruetter, Peter

    2006-02-20

    Most atomic force microscopes and cantilever-based sensors use an optical laser beam detection system to monitor cantilever deflections. We have developed a working model that accurately describes the way in which a position sensitive photodetector interprets the deflection of a cantilever in these instruments. This model exactly predicts the numerical relationship between the measured photodetector signal and the actual cantilever deflection. In addition, the model is used to optimize the geometry of such laser deflection systems, which greatly simplifies the use of any cantilever-based instrument that uses a laser beam detection system.

  2. Ultracapacitor separator

    DOEpatents

    Wei, Chang; Jerabek, Elihu Calvin; LeBlanc, Jr., Oliver Harris

    2001-03-06

    An ultracapacitor includes two solid, nonporous current collectors, two porous electrodes separating the collectors, a porous separator between the electrodes and an electrolyte occupying the pores in the electrodes and separator. The electrolyte is a polar aprotic organic solvent and a salt. The porous separator comprises a wet laid cellulosic material.

  3. Force-noise spectroscopy by tunneling current deflection sensing

    NASA Astrophysics Data System (ADS)

    Herz, Markus; Scheer, Elke

    2016-01-01

    An electro-mechanical setup for the measurement of force-noise properties in a low-temperature tunneling microscope has been utilized to enable extremely high resolution and acquire force-noise spectra as function of the applied voltage bias. The direct crosstalk of vibrations onto the tunneling current is used to measure the deflection of a force-sensing cantilever. We demonstrate its capability to measure the mechanical energy of the cantilever, caused by the noise of the force from vacuum tunneling between polycrystalline Iridium electrodes. We observe peak levels of the induced cantilever energy at polarity-symmetric voltages corresponding to dominant peaks of the phonon density of states, which suggests that inelastic transport processes contribute to force fluctuations.

  4. Photothermal cantilever deflection spectroscopy of a photosensitive polymer

    SciTech Connect

    Yun, Minhyuk; Lee, Dongkyu; Jung, Namchul; Jeon, Sangmin; Kim, Seonghwan; Chae, Inseok; Thundat, Thomas

    2012-05-14

    The mechanical and chemical information of a poly(methyl methacrylate) (PMMA) film on a microcantilever were simultaneously acquired by photothermal cantilever deflection spectroscopy as a function of ultraviolet (UV) irradiation time. Nanomechanical infrared (IR) spectra from the PMMA-coated microcantilever agreed well with the Fourier transform infrared spectroscopy (FTIR) spectra of PMMA on gold-coated silicon wafer. The decreasing intensities of nanomechanical IR peaks represent chemical as well as mechanical information of UV radiation-induced photodegradation processes in the PMMA which cannot be obtained by a conventional FTIR technique. The observed decrease in the resonance frequency of the microcantilever is related to the change in the Young's modulus of the PMMA under UV exposure.

  5. Study of surface charges in ballistic deflection transistors

    NASA Astrophysics Data System (ADS)

    Millithaler, J.-F.; Iñiguez-de-la-Torre, I.; Mateos, J.; GonzáIez, T.; Margala, M.

    2015-12-01

    This paper presents a comprehensive study of the behavior of surface charges in ballistic deflection transistors, at room temperature, where the in-plane geometry associating two drains with two gates in push-pull modes allows the control of electron path. Monte Carlo simulations were performed and compared with experimental data by using different models for accounting for surface charge effects. The simple model which assumes a constant and uniform value of the surface charge provides good results at equilibrium, but it is not able to correctly reproduce the BDT’s complex behavior when biased. We have confirmed that for a correct description of the device operation it is necessary to use a model allowing the surface charge to adapt itself locally to the carrier concentration in its surroundings.

  6. Deflection of nematicon-vortex vector solitons in liquid crystals

    NASA Astrophysics Data System (ADS)

    Assanto, Gaetano; Minzoni, Antonmaria A.; Smyth, Noel F.

    2014-01-01

    The deflection of a vector soliton formed by a solitary wave and an optical vortex in nematic liquid crystals is investigated upon interaction with a localized refractive index defect. The azimuthal instability of the vortex can be triggered by the index perturbation and enhanced by the distortion of the copropagating solitary wave when in the vicinity of the defect. A modulation theory is developed to study the refraction of the vector soliton and is found to be in good agreement with numerical solutions. This model reveals the crucial role of the diffractive radiation shed by both beam components as they evolve, showing that radiation reduces the destabilizing effect of the solitary wave interaction with the vortex, thus enlightening the effect of this continuous spectrum on the evolution of the nonlinear wave packets.

  7. Profiling compact toroid plasma density on CTIX with laser deflection

    NASA Astrophysics Data System (ADS)

    Brockington, Samuel Joseph Erwin

    A laser deflectometer measures line-integrated plasma density gradient using laser diodes and amplified point detectors. A laser passing through an optically thin plasma is refracted by an amount proportional to the line-integrated electron density gradient. I have designed, installed, and operated a deflection diagnostic for the Compact Toroid Injection Experiment (CTIX), a plasma rail gun which can create compact toroid (CT) plasmas of controllable density and velocity. The diagnostic design and motivation are discussed, as well as three experiments performed with deflectometry. Thus, my thesis consists of the design of the deflectometer diagnostic, a comparison of its accuracy to interferometer density measurements, and finally a survey of compact toroid density profiles in two dimensions conducted with an array of detectors.

  8. Fabrication and Testing of Deflecting Cavities for APS

    SciTech Connect

    Mammosser, John; Wang, Haipeng; Rimmer, Robert; Jim, Henry; Katherine, Wilson; Dhakal, Pashupati; Ali, Nassiri; Jim, Kerby; Jeremiah, Holzbauer; Genfa, Wu; Joel, Fuerst; Yawei, Yang; Zenghai, Li

    2013-09-01

    Jefferson Lab (Newport News, Virginia) in collaboration with Argonne National Laboratory (Argonne, IL) has fabricated and tested four first article, 2.8 GHz, deflecting SRF cavities, for Argonne's Short-Pulse X-ray (SPX) project. These cavities are unique in many ways including the fabrication techniques in which the cavity cell and waveguides were fabricated. These cavity subcomponents were milled from bulk large grain niobium ingot material directly from 3D CAD files. No forming of sub components was used with the exception of the beam-pipes. The challenging cavity and helium vessel design and fabrication results from the stringent RF performance requirements required by the project and operation in the APS ring. Production challenges and fabrication techniques as well as testing results will be discussed in this paper.

  9. Three-dimensional diamagnetic particle deflection in ferrofluid microchannel flows

    PubMed Central

    Liang, Litao; Zhu, Junjie; Xuan, Xiangchun

    2011-01-01

    Magnetic field-induced particle manipulation is a promising technique for biomicrofluidics applications. It is simple, cheap, and also free of fluid heating issues that accompany other common electric, acoustic, and optical methods. This work presents a fundamental study of diamagnetic particle motion in ferrofluid flows through a rectangular microchannel with a nearby permanent magnet. Due to their negligible magnetization relative to the ferrofluid, diamagnetic particles experience negative magnetophoresis and are repelled away from the magnet. The result is a three-dimensionally focused particle stream flowing near the bottom outer corner of the microchannel that is the farthest to the center of the magnet and hence has the smallest magnetic field. The effects of the particle’s relative position to the magnet, particle size, ferrofluid flow rate, and concentration on this three-dimensional diamagnetic particle deflection are systematically studied. The obtained experimental results agree quantitatively with the predictions of a three-dimensional analytical model. PMID:22662037

  10. Deflection of light to second order in conformal Weyl gravity

    NASA Astrophysics Data System (ADS)

    Sultana, Joseph

    2013-04-01

    We reexamine the deflection of light in conformal Weyl gravity obtained in Sultana and Kazanas (2010), by extending the calculation based on the procedure by Rindler and Ishak, for the bending angle by a centrally concentrated spherically symmetric matter distribution, to second order in M/R, where M is the mass of the source and R is the impact parameter. It has recently been reported in Bhattacharya et al. (JCAP 09 (2010) 004; JCAP 02 (2011) 028), that when this calculation is done to second order, the term γr in the Mannheim-Kazanas metric, yields again the paradoxical contribution γR (where the bending angle is proportional to the impact parameter) obtained by standard formalisms appropriate to asymptotically flat spacetimes. We show that no such contribution is obtained for a second order calculation and the effects of the term γr in the metric are again insignificant as reported in our earlier work.

  11. Self-contained instrument for measuring subterranean tunnel wall deflection

    DOEpatents

    Rasmussen, Donald Edgar; Hof, Jr., Peter John

    1978-01-01

    The deflection of a subterranean tunnel is measured with a rod-like, self-contained instrument that is adapted to be inserted into a radially extending bore of the tunnel adjacent an end of the tunnel where the tunnel is being dug. One end of the instrument is anchored at the end of the bore remote from the tunnel wall, while the other end of the intrument is anchored adjacent the end of the wall in proximity to the tunnel wall. The two ends of the instrument are linearly displaceable relative to each other; the displacement is measured by a transducer means mounted on the instrument. Included in the instrument is a data storage means including a paper tape recorder periodically responsive to a parallel binary signal indicative of the measured displacement.

  12. Planetary Defense: Options for Deflection of Near Earth Objects

    NASA Technical Reports Server (NTRS)

    Adams, R. B.; Statham, G.; Hopkins, R.; Chapman, J.; White, S.; Bonometti, J.; Alexander, R.; Fincher, S.; Polsgrove, T.; Kalkstein, M.

    2003-01-01

    Several recent near-miss encounters with asteroids and comets have focused attention on the threat of a catastrophic impact with the Earth. This document reviews the historical impact record and current understanding of the number and location of Near Earth Objects (NEO's) to address their impact probability. Various ongoing projects intended to survey and catalog the NEO population are also reviewed. Details are then given of an MSFC-led study, intended to develop and assess various candidate systems for protection of the Earth against NEOs. An existing program, used to model the NE0 threat, was extensively modified and is presented here. Details of various analytical tools, developed to evaluate the performance of proposed technologies for protection against the NEO threat, are also presented. Trajectory tools, developed to model the outbound path a vehicle would take to intercept or rendezvous with a target asteroid or comet, are described. Also, details are given of a tool that was created to model both the un-deflected inbound path of an NE0 as well as the modified, post-deflection, path. The number of possible options available for protection against the NE0 threat was too numerous for them to all be addressed within the study; instead, a representative selection were modeled and evaluated. The major output from this work was a novel process by which the relative effectiveness of different threat mitigation concepts can be evaluated during future, more detailed, studies. In addition, several new or modified mathematical models were developed to analyze various proposed protection systems. A summary of the major lessons learned during this study is presented, as are recommendations for future work. It is hoped that this study will serve to raise the level attention about this very real threat and also demonstrate that successful defense is both possible and practicable, provided appropriate steps are taken.

  13. Current deflection NDE for pipeline inspection and monitoring

    NASA Astrophysics Data System (ADS)

    Jarvis, Rollo; Cawley, Peter; Nagy, Peter B.

    2016-02-01

    Failure of oil and gas pipelines can often be catastrophic, therefore routine inspection for time dependent degradation is essential. In-line inspection is the most common method used; however, this requires the insertion and retrieval of an inspection tool that is propelled by the fluid in the pipe and risks becoming stuck, so alternative methods must often be employed. This work investigates the applicability of a non-destructive evaluation technique for both the detection and growth monitoring of defects, particularly corrosion under insulation. This relies on injecting an electric current along the pipe and indirectly measuring the deflection of current around defects from perturbations in the orthogonal components of the induced magnetic flux density. An array of three orthogonally oriented anisotropic magnetoresistive sensors has been used to measure the magnetic flux density surrounding a 6'' schedule-40 steel pipe carrying 2 A quasi-DC axial current. A finite element model has been developed that predicts the perturbations in magnetic flux density caused by current deflection which has been validated by experimental results. Measurements of the magnetic flux density at 50 mm lift-off from the pipe surface are stable and repeatable to the order of 100 pT which suggests that defect detection or monitoring growth of corrosion-type defects may be possible with a feasible magnitude of injected current. Magnetic signals are additionally incurred by changes in the wall thickness of the pipe due to manufacturing tolerances, and material property variations. If a monitoring scheme using baseline subtraction is employed then the sensitivity to defects can be improved while avoiding false calls.

  14. Planetary Defense From Space: Part 2 (Simple) Asteroid Deflection Law

    NASA Astrophysics Data System (ADS)

    Maccone, Claudio

    2006-06-01

    A system of two space bases housing missiles for an efficient Planetary Defense of the Earth from asteroids and comets was firstly proposed by this author in 2002. It was then shown that the five Lagrangian points of the Earth Moon system lead naturally to only two unmistakable locations of these two space bases within the sphere of influence of the Earth. These locations are the two Lagrangian points L1 (in between the Earth and the Moon) and L3 (in the direction opposite to the Moon from the Earth). In fact, placing missiles based at L1 and L3 would enable the missiles to deflect the trajectory of incoming asteroids by hitting them orthogonally to their impact trajectory toward the Earth, thus maximizing the deflection at best. It was also shown that confocal conics are the only class of missile trajectories fulfilling this “best orthogonal deflection” requirement. The mathematical theory developed by the author in the years 2002 2004 was just the beginning of a more expanded research program about the Planetary Defense. In fact, while those papers developed the formal Keplerian theory of the Optimal Planetary Defense achievable from the Earth Moon Lagrangian points L1 and L3, this paper is devoted to the proof of a simple “(small) asteroid deflection law” relating directly the following variables to each other:the speed of the arriving asteroid with respect to the Earth (known from the astrometric observations);the asteroid's size and density (also supposed to be known from astronomical observations of various types);the “security radius” of the Earth, that is, the minimal sphere around the Earth outside which we must force the asteroid to fly if we want to be safe on Earth. Typically, we assume the security radius to equal about 10,000 km from the Earth center, but this number might be changed by more refined analyses, especially in the case of “rubble pile” asteroids;the distance from the Earth of the two Lagrangian points L1 and L3 where the

  15. Surface photovoltage in exciton absorption range in CdS

    NASA Technical Reports Server (NTRS)

    Morawski, A.; Banisch, R.; Lagowski, J.

    1977-01-01

    The high resolution, intrinsic spectra of surface photovoltage are reported for semiconducting n-type CdS single crystals. At reduced temperatures (120-160 K) the spectra exhibit three sharp maxima due to A, B and C free exciton transitions. Energy positions of these lines and valence band parameters (spin-orbit and crystal field splittings) estimated from surface photovoltage are in good agreement with values obtained by other methods. The excitonic transitions are very sensitive to surface treatment, i.e. polishing, etching, background illumination and surface doping. The mechanism of direct interaction of free excitons with surface states is proposed to explain exciton lines in surface photovoltage.

  16. Analysis of splitting patterns from Stern-Gerlach magnetic deflection of supersonic molecular beams: application to M J -state-resolved deflection of J=2 atoms

    NASA Astrophysics Data System (ADS)

    Weiser, C.; Siska, P. E.

    1988-06-01

    Measurements of M J -state resolved Stern-Gerlach deflection patterns for the3 P 2 states of noble gas metastable atoms in supersonic beams are analyzed using a modification of the method originally worked out by Otto Stern. Velocity distribution breadth and beam collimation required to resolve the M J states are explored, and the modeling is improved by including variation in the field gradient along the deflected atomic trajectories.

  17. Facile microwave-assisted aqueous synthesis of CdS nanocrystals with their photocatalytic activities under visible lighting

    SciTech Connect

    Deng, Chonghai; Tian, Xiaobo

    2013-10-15

    Graphical abstract: - Highlights: • Three kinds of CdS nanostructures have been controllably synthesized. • Ethanediamine acts as a phase and morphology controlling reagent. • Three CdS nanostructures display high visible light photocatalytic activities. • Cubic CdS-3 shows superior photocatalytic activity to the other hexagonal CdS. • The growth processes for fabrication of CdS nanocrystals are also discussed. - Abstract: Three kinds of CdS nanostructures, that is, hexagonal nanospheres (CdS-1), hierarchical caterpillar-fungus-like hexagonal nanorods (CdS-2) and hierarchical cubic microspheres (CdS-3), were controllably synthesized by a facile and one-pot microwave-assisted aqueous chemical method using ethanediamine as a phase and morphology controlling reagent. The as-prepared products were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), UV–vis diffuse reflectance spectra (DRS) and photoluminescence (PL) spectra. The results show that CdS-1 is mainly composed of monodispersed hexagonal nanospheres with average diameters of about 100 nm; hexagonal CdS-2 has lengths in the range of 600–800 nm and diameters of 40–60 nm, assembled by nanoparticles about 20 nm in diameter; and CdS-3 is pure cubic microspheres with diameters in the range of 0.8–1.3 μm, aggregated by tiny nanograins with size of 5.8 nm. The band gap energies of CdS products were calculated to be 2.30, 2.31 and 2.24 eV observed from UV–vis DRS for CdS-1, CdS-2 and CdS-3, respectively. PL spectra of CdS samples showed that sphalerite CdS-3 possesses a very weak fluorescence, while wurtzite CdS-2 has a strongest green near-band edge emission (NBE) at 550 nm. The visible light photodegradation of methylene blue and rhodamine B in the presence of CdS photocatalysts illustrates that all of them display high photocatalytic activities. Significantly, the cubic CdS-3 exhibits more excellent photocatalytic

  18. Enhanced visible light photocatalytic performance of ZnO nanowires integrated with CdS and Ag2S.

    PubMed

    Chen, Chienhua; Li, Zhengcao; Lin, Hehnan; Wang, Guojing; Liao, Jiecui; Li, Mingyang; Lv, Shasha; Li, Wei

    2016-02-18

    A series of ZnO-CdS-Ag2S ternary nanostructures with different amounts of Ag2S were prepared using simple and low-cost successive ionic layer adsorption and reaction (SILAR) and a chemical precipitation method. The ZnO nanowires, with a diameter of ∼100 nm and a length of ∼1 μm, were modified by coating CdS and Ag2S. CdS has a high absorption coefficient and can efficiently match with the energy levels of ZnO, which can enhance the light absorption ability of the nanostructures. In addition, Ag2S with a narrow band gap was used as the main light absorber and played an important role in increasing the light absorption in the visible light region. The photocatalytic activity of the ZnO-CdS-Ag2S ternary nanostructures was investigated using the degradation of methyl orange (MO) in an aqueous solution under visible light. The ZnO-CdS-Ag2S ternary nanostructures were found to be more efficient than ZnO nanowires, ZnO-CdS nanowires, and ZnO-Ag2S nanowires. There is 7.68 times more photocatalytic activity for MO degradation in terms of the rate constant for ZnO-CdS-Ag2S 15-cycle ternary nanostructure compared to the as-grown ZnO. Furthermore, the effect of the amount of Ag2S and CdS on the ZnO surface on the photocatalytic activity was analyzed. The superior photo-absorption properties and photocatalytic performance of the ZnO-CdS-Ag2S ternary nanostructures can be ascribed to the heterostructure, which enhanced the separation of the photo-induced electron-hole pairs. In addition, visible light could be absorbed by ZnO-CdS-Ag2S ternary nanostructures rather than by ZnO. PMID:26815888

  19. On the strong influence of the photoelastic effect in the collinear mirage deflection

    NASA Astrophysics Data System (ADS)

    Salazar, A.; Gateshki, M.; Sánchez-Lavega, A.

    2000-05-01

    We report in this letter on the strong influence of the polarization state of the probe beam in the amplitude and phase of the collinear mirage deflection. A model of the collinear mirage deflection that takes into account the photoelastic effect in the sample has been developed. The agreement between the model predictions and the experimental results is excellent.

  20. Evaluation of disparate laser beam deflection technologies by means of number and rate of resolvable spots.

    PubMed

    Bechtold, Peter; Hohenstein, Ralph; Schmidt, Michael

    2013-08-15

    We introduce a method to objectively evaluate systems of differing beam deflection technologies that commonly are described by disparate technical specifications. Using our new approach based on resolvable spots we will compare commercially available random-access beam deflection technologies, namely galvanometer scanners, piezo scanners, MEMS scanners, acousto-optic deflectors, and electro-optic deflectors. PMID:24104614

  1. The buckling of a column on equally spaced deflectional and rotational springs

    NASA Technical Reports Server (NTRS)

    Budiansky, Bernard; Seide, Paul; Weinberger, Robert A

    1948-01-01

    A solution is presented for the problem of the buckling of a column on equally spaced deflectional and rotational springs. Useful charts, which relate deflectional spring stiffness, rotational spring stiffness, and buckling load, are given for columns having two, three, four, and infinite number of spans.

  2. ForeCAT - A Model for Magnetic Deflections of Coronal Mass Ejections

    NASA Astrophysics Data System (ADS)

    Kay, Christina; Opher, Merav

    2016-05-01

    Accurate space weather forecasting requires knowledge of the trajectory of CMEs. Decades of observations show that CMEs can deflect from a purely radial trajectory, however, no consensus exists as to the cause of these deflections. We developed a model for CME deflection and rotation from magnetic forces, called Forecasting a CME’s Altered Trajectory (ForeCAT). ForeCAT has been designed to run fast enough for large parameter phase space studies, and potentially real-time predictions.ForeCAT reproduces the general trends seen in observed CME deflections. In particular, CMEs deflect toward regions of minimum magnetic energy - frequently the Heliospheric Current Sheet (HCS) on global scales. The background magnetic forces decrease rapidly with distance and quickly become negligible. Most deflections and rotations can be well-described by assuming constant angular momentum beyond 10 Rs.ForeCAT also reproduces individual observed CME deflections - the 2008 December 12, 2008 April 08, and 2010 July 12 CMEs. By determining the reduced chi-squared best fit between the ForeCAT results and the observations we constrain parameters related to the CME and the background solar wind. Additionally, we constrain whether different models for the low corona magnetic backgrounds can produce the observed CME deflection.

  3. Synthesis of monodispersed CdS nanoballs through {gamma}-irradiation route and building core-shell structure CdS SiO{sub 2}

    SciTech Connect

    Wang Zhaoxu; Chen Jiafu Xue Xuan; Hu Yong

    2007-12-04

    Monodispersed CdS nanoballs were synthesized through {gamma}-irradiating CdCl{sub 2}, Na{sub 2}S{sub 2}O{sub 3} and polyvinylpyrrolidone aqueous solution at room temperature. With these well monodispersed CdS nanoballs, CdS SiO{sub 2} core-shell structures were prepared under hydrolysis of tetraethylorthosilicate without adding a coupling agent. Field emission scanning electron micrograph, transmission electron microscopy, X-ray powder diffraction, X-ray photoelectron spectroscopy, ultraviolet absorption and photoluminescence spectroscopy were used to characterize the products. It is hoped that the core-shell CdS SiO{sub 2} nanoballs would be used as good luminescence detecting material for biological systems, so this may stimulate technological interest and prospect many other applications in materials related fields.

  4. BI Reporting, Data Warehouse Systems, and Beyond. CDS Spotlight Report. Research Bulletin

    ERIC Educational Resources Information Center

    Lang, Leah; Pirani, Judith A.

    2014-01-01

    This Spotlight focuses on data from the 2013 Core Data Service [CDS] to better understand how higher education institutions approach business intelligence (BI) reporting and data warehouse systems (see the Sidebar for definitions). Information provided for this Spotlight was derived from Module 8 of CDS, which contains several questions regarding…

  5. Surface modification of CdS quantum dots using thiols—structural and photophysical studies

    NASA Astrophysics Data System (ADS)

    Thangadurai, P.; Balaji, S.; Manoharan, P. T.

    2008-10-01

    This study is aimed at identifying a suitable organic thiol for CdS by studying its structural, thermal and photophysical characteristics. Quantum dots of the II-VI semiconductor CdS, in the size regime of 2.0-3.3 nm, were prepared in the cubic phase by a wet chemical method. Five organic thiols were used for capping: (i) 1,4-dithiothreitol (DTT), (ii) 2-mercaptoethanol (ME), (iii) cysteine (Cys), (iv) methionine (Meth), and (v) glutathione (GSH). Structural studies were carried out by x-ray diffraction (XRD) and transmission electron microscopy (TEM), which revealed the cubic phase of CdS. Optical properties were studied by FT-IR, UV-visible and fluorescence spectroscopic techniques, and a comparison was made between uncapped and capped CdS. FT-IR studies suggested two different bonding mechanisms of the capping agents with the CdS. GSH and DTT capped CdS showed significant decrease in absorption wavelengths. An increase in band gap was observed in two cases: when (i) capped and (ii) decreased in size. The band gap was increased from 2.50 eV for the uncapped to 2.77 eV for the DTT capped CdS. DTT was found to be the best capping agent for CdS among these five organic thiols in two aspects: (i) yielding lower grain size in cubic phase, and (ii) good fluorescence properties with efficient quenching of the surface traps.

  6. White luminescence from CdS nanocrystals under the blue light excitation

    SciTech Connect

    Li, Bo; Zhang, Xiaosong Li, Lan; Li, Mengzhen; Xu, Jianping; Hong, Yuan

    2014-06-01

    Trap-rich CdS nanocrystals were synthesized by employing CdSt{sub 2} and sulfur as precursors via thermal decomposition. Furthermore, X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), absorption and photoluminescence (PL) spectra were used to characterize structure, morphology and luminescence properties of CdS nanocrystals (NCs). CdS NCs have a broad emission across 500–700 nm under the excitation of blue light with 460 nm, consequently, white light can be produced by mixing broad emission from CdS NCs excited by blue light, with the remaining blue light. In addition, the broad emission generation is closely and inseparably related to surface defects. Moreover, LaMer model was used to explain the phenomenon that the intensity of the trap emission gradually decreases as the reaction time increases in contrast with that of the band-edge emission. - Graphical abstract: Trap-rich CdS nanocrystals were synthesized. Furthermore, white light is produced by mixing broad emission across 500–700 nm from CdS NCs excited by blue light, in combination with the remaining blue light. - Highlights: • Trap-rich CdS nanocrystals were synthesized. • CdS NCs have a broad emission across 500–700 nm under the excitation of blue light. • White light can be produced by mixing broad emission with the remaining blue light.

  7. The Financial Management System: A Pivotal Tool for Fiscal Viability. CDS Spotlight. ECAR Research Bulletin

    ERIC Educational Resources Information Center

    Lang, Leah; Pirani, Judith A.

    2014-01-01

    This spotlight focuses on data from the 2013 CDS to better understand how higher education institutions approach financial management systems. Information provided for this spotlight was derived from Module 8 of Core Data Service (CDS), which asked several questions regarding information systems and applications. Responses from 525 institutions…

  8. Ultrasonic/surfactant assisted of CdS nano hollow sphere synthesis and characterization

    SciTech Connect

    Rafati, Amir Abbas; Borujeni, Ahmad Reza Afraz; Najafi, Mojgan; Bagheri, Ahmad

    2011-01-15

    CdS hollow nanospheres with diameters ranging from 40 to 150 nm have been synthesized by a surfactant-assisted sonochemical route. The successful vesicle templating indicates that the outer leaflet of the bilayer is the receptive surface in the controlled growth of CdS nanoparticles which provide the unique reactor for the nucleation and mineralization growth of CdS nanoparticles. The CdS nanostructures obtained were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, ultraviolet-visible spectroscopy and photoluminescence spectroscopy. Structural characterization of hollow CdS nanospheres indicates that these products packed with square subunits having sizes between 5 and 7 nm in diameter. The formation of the hollow nanostructure was explained by a vesicle template mechanism, in which sonication and surfactant play important roles. The band-edge emission and surface luminescence of the CdS nanoparticles were observed. -Research Highlights: {yields} CdS hollow nanospheres with diameters of 40-150 nm were synthesized. {yields} Nanoparticles were characterized by UV/Vis and photoluminescence. {yields} Nanospheres are composed of smaller nanocrystals with the average size of 6.8 nm. {yields} The band gap energy of the CdS nanoparticles is higher than its bulk value.

  9. A new synthesis strategy for chiral CdS nanotubes based on a homochiral MOF template.

    PubMed

    Kuang, Xuan; Ma, Yu; Zhang, Caiyun; Su, Hao; Zhang, Jine; Tang, Bo

    2015-04-01

    We describe for the first time a convenient technique to prepare helical CdS nanotubes, with a MOF as the template. The prepared helical CdS nanotubes were remarkably sensitive to D/L-aspartic acid (Asp) and can be used as a potential sensor for enantioselective recognition of D/L-Asp. PMID:25735867

  10. The Ever-Present Demand for Public Computing Resources. CDS Spotlight

    ERIC Educational Resources Information Center

    Pirani, Judith A.

    2014-01-01

    This Core Data Service (CDS) Spotlight focuses on public computing resources, including lab/cluster workstations in buildings, virtual lab/cluster workstations, kiosks, laptop and tablet checkout programs, and workstation access in unscheduled classrooms. The findings are derived from 758 CDS 2012 participating institutions. A dataset of 529…

  11. Mechanistic aspects of biogenic synthesis of CdS nanoparticles using Bacillus licheniformis

    NASA Astrophysics Data System (ADS)

    Tripathi, R. M.; Singh Bhadwal, Akhshay; Singh, Priti; Shrivastav, Archana; Singh, M. P.; Shrivastav, B. R.

    2014-06-01

    A novel eco-friendly effort has been made for the synthesis of cadmium sulfide (CdS) nanoparticles using bacterial biomass. Although some articles have been reported on CdS nanoparticles synthesis by bacteria, here we have synthesized CdS nanoparticles using non-pathogenic bacteria Bacillus licheniformis MTCC 9555. UV-Vis spectroscopy was carried out to confirm the formation of CdS nanoparticles; the peak occurring at 368 nm gives the indication of synthesis of CdS nanoparticles. The size and morphology of the synthesized CdS nanoparticles were analyzed by transmission electron microscopy (TEM) and the nanoparticles are found to have a narrow size of 5.1 ± 0.5 nm with spherical morphology. Further, the nanoparticles were examined by energy dispersive x-ray (EDX) spectroscopy to identify the presence of elements and confirmed the existence of Cd and S in single nanoparticles. X-ray diffraction (XRD) analysis exhibited 2θ values corresponding to CdS nanocrystals. Fourier transform infrared spectroscopy (FTIR) provides the evidence for the presence of proteins as possible biomolecules responsible for the stabilization of the synthesized CdS nanoparticles.

  12. Preparation of CdS Nanoparticles by First-Year Undergraduates

    ERIC Educational Resources Information Center

    Winkelmann, Kurt; Noviello, Thomas; Brooks, Stephen

    2007-01-01

    The first year undergraduates use a simple method to synthesize 5-nm CdS nanoparticles in a water-in-oil microemulsion. The quantum size effect, the relationship between colors, optical absorbance, band-gap energy and the CdS particles affected by the formation of micelles are observed.

  13. Isolation and characterization of murine Cds (CDP-diacylglycerol synthase) 1 and 2.

    PubMed

    Inglis-Broadgate, Suzanne L; Ocaka, Louise; Banerjee, Ruby; Gaasenbeek, Michelle; Chapple, J Paul; Cheetham, Michael E; Clark, Brian J; Hunt, David M; Halford, Stephanie

    2005-08-15

    Phototransduction in Drosophila is a phosphoinositide-mediated signalling pathway. Phosphatidylinositol 4,5-bisphosphate (PIP2) plays a central role in this process, and its levels are tightly regulated. A photoreceptor-specific form of the enzyme CDP-diacylglycerol synthase (CDS), which catalyzes the formation of CDP-diacylglycerol from phosphatidic acid, is a key regulator of the amount of PIP2 available for signalling. cds mutants develop light-induced retinal degeneration. We report here the isolation and characterization of two murine genes encoding this enzyme, Cds1 and Cds2. The genes encode proteins that are 73% identical and 92% similar but exhibit very different expression patterns. Cds1 shows a very restricted expression pattern but is expressed in the inner segments of the photoreceptors whilst Cds2 shows a ubiquitous pattern of expression. Using fluorescent in situ hybridization we have mapped Cds1 and Cds2 to chromosomes 5E3 and 2G1 respectively. These are regions of synteny with the corresponding human gene localization (4q21 and 20p13). Transient transfection experiments with epitope tagged proteins have also demonstrated that both are associated with the endoplasmic reticulum. PMID:16023307

  14. "I'm Not Mentally Ill": Identity Deflection as a Form of Stigma Resistance.

    PubMed

    Thoits, Peggy A

    2016-06-01

    Mental illness identity deflection refers to rebuffing the idea that one is mentally ill. Predictors of identity deflection and its consequences for well-being were examined for individuals with mental disorders in the National Comorbidity Study-Replication (N = 1,368). Respondents more often deflected a mental illness identity if they had a nonsevere disorder, had low impairment in functioning, had no treatment experience, viewed possible treatment as undesirable, and held multiple social roles, consistent with theory about stigma resistance. Persons who deflected a mental illness identity had lower distress and more positive affect than those who accepted it, even net of disorder severity, impairment level, and treatment experience. Among those who had ever been in treatment, deflection buffered the negative effects of serious impairment but exacerbated the effects of having a severe disorder on well-being, suggesting more complex consequences of formal labeling (greater stigma but helpful services), consistent with previous research. PMID:27284073

  15. Optical properties of colloidal aqueous synthesized 3 mercaptopropionic acid stabilized CdS quantum dots

    NASA Astrophysics Data System (ADS)

    Sumanth Kumar, D.; Jai Kumar, B.; Mahesh H., M.

    2016-05-01

    We have explored an easiest and simplest aqueous route to synthesize bright green luminescent CdS QDs using 3-Mercaptopropionic acid (MPA) as a stabilizer in air ambient for solar cell applications. The CdS quantum dots showed a strong quantum confinement effect with good stability, size and excellent photoluminescence. MPA Capping on CdS QDs was confirmed through FTIR. The Optical absorption spectrum revealed the CdS quantum dots are highly transparent in the visible region with absorption peak at 380 nm, confirming the quantum confinement. Photoluminescence showed an emission peak at 525 nm wavelength. The optical band gap energy was found to be 3.19 eV and CdS quantum dots radius calculated using Brus equation is 1.5 nm. The results are presented and discussed in detail.

  16. Mesoporous structured MIPs@CDs fluorescence sensor for highly sensitive detection of TNT.

    PubMed

    Xu, Shoufang; Lu, Hongzhi

    2016-11-15

    A facile strategy was developed to prepare mesoporous structured molecularly imprinted polymers capped carbon dots (M-MIPs@CDs) fluorescence sensor for highly sensitive and selective determination of TNT. The strategy using amino-CDs directly as "functional monomer" for imprinting simplify the imprinting process and provide well recognition sites accessibility. The as-prepared M-MIPs@CDs sensor, using periodic mesoporous silica as imprinting matrix, and amino-CDs directly as "functional monomer", exhibited excellent selectivity and sensitivity toward TNT with detection limit of 17nM. The recycling process was sustainable for 10 times without obvious efficiency decrease. The feasibility of the developed method in real samples was successfully evaluated through the analysis of TNT in soil and water samples with satisfactory recoveries of 88.6-95.7%. The method proposed in this work was proved to be a convenient and practical way to prepare high sensitive and selective fluorescence MIPs@CDs sensors. PMID:27315521

  17. A biocatalytic approach towards synthesis of polymer CdS nanocomposites

    SciTech Connect

    Banerjee, S.; Premchandran, R.; Baumgartner, T.

    1996-10-01

    Copolymers of hydroxythiophenol and ethylphenol have been prepared using a biocatalytic route. Specifically, the method utilizes an oxidative enzyme, horseradish peroxidase, solubilized within the aqueous phase of a AOT/isooctane microemulsion. The monomers are oil soluble and are thus present in the organic phase. High conversions are obtained upto 1:1 molar ratio of the two monomers. The resulting polymers have the overall morphology of interconnected submicron spheres and are soluble in common organic solvents. Following their synthesis these copolymers have been derivatized by attaching Q-sized CdS particles. Though the copolymer itself is nonfluorescent, the CdS nanoclusters within it can be selectively excited and made to fluoresce. The fluorescent properties of the polymer CdS composite are distinctive from underivatized CdS or hydroxythiophenol monomer capped CdS.

  18. Separated flow

    NASA Technical Reports Server (NTRS)

    Sellers, W. L., III; Dunham, R. E., Jr.; Goodman, W. L.; Howard, F. G.; Margason, R. J.; Rudy, D. H.; Rumsey, C. L.; Stough, H. P., III; Thomas, J. L.

    1986-01-01

    A brief overview of flow separation phenomena is provided. Langley has many active research programs in flow separation related areas. Three cases are presented which describe specific examples of flow separation research. In each example, a description of the fundamental fluid physics and the complexity of the flow field is presented along with a method of either reducing or controlling the extent of separation. The following examples are discussed: flow over a smooth surface with an adverse pressure gradient; flow over a surface with a geometric discontinuity; and flow with shock-boundary layer interactions. These results will show that improvements are being made in the understanding of flow separation and its control.

  19. Self-assembling endohedrally doped CdS nanoclusters: new porous solid phases of CdS.

    PubMed

    Jimenez-Izal, Elisa; Matxain, Jon M; Piris, Mario; Ugalde, Jesus M

    2012-07-21

    Hollow CdS nanoclusters were predicted to trap alkali metals and halogen atoms inside their cavity. Furthermore, electron affinities (EA) of endohedrally halogen doped clusters and ionization potentials (IE) of endohedrally alkali doped clusters were predicted to be very similar. This makes them suitable to build cluster-assembled materials, in the same vein as do related ZnO, ZnS and MgO nanoclusters, which yield porous solid materials. With this aim in mind, we have focused on the assembly of bare Cd(i)S(i) and endohedral K@Cd(i)S(i)-X@Cd(i)S(i) (i = 12, 16, X = Cl, Br) clusters in order to obtain solids with tailored semiconducting and structural properties. Since these hollow nanoclusters possess square and hexagonal faces, three different orientations have to be considered, namely, edge-to-edge (E-E), square-to-square (S-S) and hexagon-to-hexagon (H-H). These three orientations lead to distinct zeolite-like nanoporous bulk CdS solid phases denoted as SOD, LTA and FAU. These solids are low-density crystalline nanoporous materials that might be useful in a wide range of applications ranging from molecular sieves for heterogeneous catalysis to gas storage templates. PMID:22684728

  20. Molecular Aggregates in Stable Aqueous Three-Phase Surfactant Systems and Their use in Producing CdS Nanowires

    PubMed Central

    Dong, Renhao; Zhou, Liang; Wang, Dong; Hao, Jingcheng

    2013-01-01

    Aqueous three-phase surfactant systems (A3PS) are important, multicomponent, stable three-phase equilibria with coexisting forms in a common colloid solution, but have been largely ignored regarding further characterization and application. Mixing simple, commercially available, single-tailed anionic/nonionic or anionic/cationic surfactants in water can spontaneously produce stable A3PS with coexisting multiscale self-assembled structures including discs, lamellas, micelles and vesicles. As with conventional aqueous two-phase systems (A2PS), A3PS can be applied in partition and extraction processes. Here, the A3PS was also used as a mild media for one-step synthesis of multiscale CdS nanowires. Particularly, the A3PS does not change and simultaneously separates the CdS nanowires with the comparable size in one phase, which provides a facile strategy for collection of monodisperse nanomaterials. We expect that this present work can expand recognition of A3PS for use in theoretical and applied studies. PMID:23588712

  1. Comparing deflection measurements of a magnetically steerable catheter using optical imaging and MRI

    SciTech Connect

    Lillaney, Prasheel Caton, Curtis; Martin, Alastair J.; Losey, Aaron D.; Evans, Leland; Saeed, Maythem; Cooke, Daniel L.; Wilson, Mark W.; Hetts, Steven W.

    2014-02-15

    Purpose: Magnetic resonance imaging (MRI) is an emerging modality for interventional radiology, giving clinicians another tool for minimally invasive image-guided interventional procedures. Difficulties associated with endovascular catheter navigation using MRI guidance led to the development of a magnetically steerable catheter. The focus of this study was to mechanically characterize deflections of two different prototypes of the magnetically steerable catheterin vitro to better understand their efficacy. Methods: A mathematical model for deflection of the magnetically steerable catheter is formulated based on the principle that at equilibrium the mechanical and magnetic torques are equal to each other. Furthermore, two different image based methods for empirically measuring the catheter deflection angle are presented. The first, referred to as the absolute tip method, measures the angle of the line that is tangential to the catheter tip. The second, referred to the base to tip method, is an approximation that is used when it is not possible to measure the angle of the tangent line. Optical images of the catheter deflection are analyzed using the absolute tip method to quantitatively validate the predicted deflections from the mathematical model. Optical images of the catheter deflection are also analyzed using the base to tip method to quantitatively determine the differences between the absolute tip and base to tip methods. Finally, the optical images are compared to MR images using the base to tip method to determine the accuracy of measuring the catheter deflection using MR. Results: The optical catheter deflection angles measured for both catheter prototypes using the absolute tip method fit very well to the mathematical model (R{sup 2} = 0.91 and 0.86 for each prototype, respectively). It was found that the angles measured using the base to tip method were consistently smaller than those measured using the absolute tip method. The deflection angles measured

  2. Concrete deflection measurement using fiber optic distributed strain system

    NASA Astrophysics Data System (ADS)

    Papes, Martin; Jaros, Jakub; Fajkus, Marcel; Hurta, Jan; Liner, Andrej; Hruby, David; Vasinek, Vladimir

    2015-07-01

    The monitoring of building structures deformations and testing of construction materials resilience are very important processes in the development and production of given materials and structures. Undesirable or excessive deformations of materials are phenomena which are unacceptable in construction, especially in supporting structures. These issues are currently monitored by electromechanical sensor in most cases. It is a classic technique when the sensor measures the material stress at the point of its installation. This paper deals with the concrete deflection measurement using fiber optic distributed strain system. This system uses optical fiere as a sensor and operates at the principle of measurement of Brillouin frequencies. The mechanical stress on the optical fiber causes shift of these frequencies. This change is subsequently converted to stress unit micro-strain. In our experiments, the optical fiber was embedded in concrete along its whole length. The advantage of this system is that the measurement is carrying out along the entire fiber length with spatial resolution around 50 cm, so it is possible continuously measure several thousands of points at the distance of several kilometers.

  3. Three-dimensional parabolic equation modeling of mesoscale eddy deflection.

    PubMed

    Heaney, Kevin D; Campbell, Richard L

    2016-02-01

    The impact of mesoscale oceanography, including ocean fronts and eddies, on global scale low-frequency acoustics is examined using a fully three-dimensional parabolic equation model. The narrowband acoustic signal, for frequencies from 2 to 16 Hz, is simulated from a seismic event on the Kerguellen Plateau in the South Indian Ocean to an array of receivers south of Ascension Island in the South Atlantic, a distance of 9100 km. The path was chosen for its relevance to seismic detections from the HA10 Ascension Island station of the International Monitoring System, for its lack of bathymetric interaction, and for the dynamic oceanography encountered as the sound passes the Cape of Good Hope. The acoustic field was propagated through two years (1992 and 1993) of the eddy-permitting ocean state estimation ECCO2 (Estimating the Circulation and Climate of the Ocean, Phase II) system. The range of deflection of the back-azimuth was 1.8° with a root-mean-square of 0.34°. The refraction due to mesoscale oceanography could therefore have significant impacts upon localization of distant low-frequency sources, such as seismic or nuclear test events. PMID:26936572

  4. Nuclear Explosives for the Purpose of Deflecting Asteroids

    NASA Astrophysics Data System (ADS)

    Chapman, Dave

    2001-06-01

    In order to deflect asteroids or comets having a diameter over 1 kilometer, it will be necessary to use nuclear explosives. Nuclear devices which deliver a large fraction of their total yield in the form of neutrons are considerably more effective for producing a velocity change in the target than devices which deliver x-rays or gamma rays. Typical megaton-range nuclear weapons currently deployed are a three-stage design (fission-fusion-fission) which emit most of their energy in the form of x-rays. Certain megaton-range nuclear weapons currently deployed are a two-stage design. These devices are often described as "tactical" or "clean" nuclear weapons. Because of the density of fusion fuel required to give an efficient burn, each neutron produced by the device experiences a large number of collisions before it is able to escape from the device. These collisions remove energy from the neutrons and cause most of the total device energy to be emitted as x-rays. (High-yield devices developed for military purposes have been optimized for maximum yield or for maximum yield subject to some limit on total radioactive isotope emissions. Those devices which have been optimized for radiation, known as "neutron bombs", are in the kiloton range, not the megaton range. If it is necessary to develop megaton-range nuclear explosives which have been optimized for total neutron energy output, then these devices should be developed while experienced bomb designers are still available.)

  5. Moth tails divert bat attack: Evolution of acoustic deflection

    PubMed Central

    Barber, Jesse R.; Leavell, Brian C.; Keener, Adam L.; Breinholt, Jesse W.; Chadwell, Brad A.; McClure, Christopher J. W.; Hill, Geena M.; Kawahara, Akito Y.

    2015-01-01

    Adaptations to divert the attacks of visually guided predators have evolved repeatedly in animals. Using high-speed infrared videography, we show that luna moths (Actias luna) generate an acoustic diversion with spinning hindwing tails to deflect echolocating bat attacks away from their body and toward these nonessential appendages. We pit luna moths against big brown bats (Eptesicus fuscus) and demonstrate a survival advantage of ∼47% for moths with tails versus those that had their tails removed. The benefit of hindwing tails is equivalent to the advantage conferred to moths by bat-detecting ears. Moth tails lured bat attacks to these wing regions during 55% of interactions between bats and intact luna moths. We analyzed flight kinematics of moths with and without hindwing tails and suggest that tails have a minimal role in flight performance. Using a robust phylogeny, we find that long spatulate tails have independently evolved four times in saturniid moths, further supporting the selective advantage of this anti-bat strategy. Diversionary tactics are perhaps more common than appreciated in predator–prey interactions. Our finding suggests that focusing on the sensory ecologies of key predators will reveal such countermeasures in prey. PMID:25730869

  6. String formulation of space charge forces in a deflecting bunch

    NASA Astrophysics Data System (ADS)

    Talman, Richard

    2004-10-01

    The force between two moving point charges, because of its inverse square law singularity, cannot be applied directly in the numerical simulation of bunch dynamics; radiative effects make this especially true for short bunches being deflected by magnets. This paper describes a formalism circumventing this restriction in which the basic ingredient is the total force on a point charge comoving with a longitudinally aligned, uniformly charged string. Bunch evolution can then be treated using direct particle-to-particle, intrabeam scattering, with no need for an intermediate, particle-in-cell, step. Electric and magnetic fields do not appear individually in the theory. Since the basic formulas are both exact (in paraxial approximation) and fully relativistic, they are applicable to beams of all particle types and all energies. But the theory is expected to be especially useful for calculating the emittance growth of the ultrashort electron bunches of current interest for energy recovery linacs and free-electron lasers. The theory subsumes coherent synchrotron radiation and centrifugal space charge force. Renormalized, on-axis, longitudinal field components are in excellent agreement with values from Saldin et al. [DESY Report No. DESY-TESLA-FEL-96-14, 1995;

    Nucl. Instrum. Methods Phys. Res., Sect. ANIMAER0168-9002 417, 158 (1998).10.1016/S0168-9002(98)00623-8

  7. Optimization criteria for standing wave transverse magnetic deflection cavities

    SciTech Connect

    Haimson, J.

    1995-08-01

    An important linear accelerator requirement, in order to demonstrate narrow energy spectra, is the injection of electron bunches of narrow phase spread and negligible inter-bunch current. This can be achieved by r-f transverse modulation and clipping of the beam by an aperture prior to injection into the accelerator waveguide, i.e., chopper operation. By magnetically biasing the beam to one side of the centerline, it is possible to arrange for transmission into the accelerator at a time during each r-f cycle when the radial momentum imparted to the beam by the chopper cavity is passing through zero. The low efficiency of beam utilization normally associated with this type of operation, because of the high ratio of collected to transmitted current, can be considerably improved by combining the transverse chopping action with a suitably phased longitudinal velocity modulating field as obtained from a simple prebunching cavity. Transverse r-f deflection techniques also enable sub-harmonic bunch selection and injection into linear accelerators which are used as injectors for electron synchrotrons. This is achieved by driving the chopper cavity at the same frequency as the synchrotron r-f system (which is maintained at a precise sub-multiple of the linear accelerator fundamental frequency) and then prebunching the chopped beam at the fundamental frequency prior to injection into the linear accelerator.

  8. Operating Deflection Shapes for the Space Shuttle Partial Stack Rollout

    NASA Technical Reports Server (NTRS)

    Buehrle, Ralph D.; Kappus, Kathy

    2005-01-01

    In November of 2003 a rollout test was performed to gain a better understanding of the dynamic environment for the Space Shuttle during transportation from the Vehicle Assembly Building to the launch pad. This was part of a study evaluating the methodology for including the rollout dynamic loads in the Space Shuttle fatigue life predictions. The rollout test was conducted with a partial stack consisting of the Crawler Transporter, Mobile Launch Platform, and the Solid Rocket Boosters with an interconnecting crossbeam. Instrumentation included over 100 accelerometers. Data was recorded for steady state speeds, start-ups and stops, and ambient wind excitations with the vehicle at idle. This paper will describe the operating deflection shape analysis performed using the measured acceleration response data. The response data for the steady state speed runs were dominated by harmonics of the forcing frequencies, which were proportional to the vehicle speed. Assuming a broadband excitation for the wind, analyses of the data sets with the vehicle at idle were used to estimate the natural frequencies and corresponding mode shapes. Comparisons of the measured modal properties with numerical predictions are presented.

  9. A simple damage detection indicator using operational deflection shapes

    NASA Astrophysics Data System (ADS)

    Sampaio, R. P. C.; Maia, N. M. M.; Almeida, R. A. B.; Urgueira, A. P. V.

    2016-05-01

    Catastrophic structural failure of aircrafts, bridges, buildings and other structures in modern societies has always been of primary concern because of the loss of human lifes and of negative economic impact. The aging of the structures, the growing dependency on their role in our networks of transportation, energy and comunications, the smaller construction tolerances, the bigger power demanded and the media and society awardness to catastrophic events are sufficient motivations for the growing field of structural health monitoring, which aims at assessing the actual condition of a structure and to identify incipient damage. Damage identification can be considered as a two step process, the detection and the diagnosis. The former, and fundamental step, is the confirmation of an efective damage existence. When the response is affirmative, the latter step begins with the diagnosis, and then the questions are: where?, how much?, what type?, when will it fail? In this paper the authors propose a simple method to detect and relatively quantify structural damage by using measured vibrations data, specifically the operational deflections shapes. Numerical simulations and experimental tests are presented to validate the proposed method.

  10. Photonic microsystems: an enabling technology for light deflection and modulation

    NASA Astrophysics Data System (ADS)

    Schenk, Harald; Wolter, Alexander; Dauderstadt, Ulrike A.; Gehner, Andreas; Grueger, Heinrich; Drabe, Christian; Lakner, Hubert

    2004-01-01

    Light and electricity are said to be the all purpose tools for the next decades. Photonic Microsystems combine this tools in an ideal manner: They are electronically addressable devices with an optical functionality allowing to modulate light temporally and/or spatially. Further, they take advantage of high integration density, high reliability, high bandwidth and low cost fabrication for serial production. While in some cases Photonic Microsystem Technology is focused on the replacement of conventional devices, the majority of developments uses the unique potential of this technology to create devices based on novel principles with extended or even new functionality for advanced applications. Products based on Photonic Microsystem Technology have already entered or are only a few steps away from entering the market in various fields e.g. in information and communication technology, medicine, biology and metrology. This paper gives an overview of the Photonic Microsystems development activities with special emphasis on devices for light deflection and light modulation. Single micro mirrors e.g. for scanning or laser beam positioning are as well presented and discussed as micro mirror arrays and membrane mirrors for image generation and phase modulation. Technology trends are derived from the current development activities and an outlook to future work is given.

  11. Experimental investigation of the evacuation effect in expansion deflection nozzles

    NASA Astrophysics Data System (ADS)

    Taylor, N. V.; Hempsell, C. M.; Macfarlane, J.; Osborne, R.; Varvill, R.; Bond, A.; Feast, S.

    2010-02-01

    This paper provides an overview of results generated by the static test expansion-deflection rocket nozzle (STERN) project. The engine propellants were gaseous air and hydrogen, with a design chamber pressure and thrust of 102 bar and 5 kN respectively. The maximum chamber pressure achieved was restricted to 55 bar absolute, due to a conservative approach in the test programme dictated by the uncertainty in heat transfer to the pintle. Despite this, the programme achieved many successes, including the first tests of an ED nozzle in the UK; the production of significant amounts of data for both the analysis of the performance of the nozzle and the verification of analysis codes; and an improved compensation performance over that apparent from earlier work, including demonstration of attached flow to the exit plane for all chamber pressures. Whilst the wake pressure was not as high as hoped, ranging between 70% and 95% of ambient and apparently inversely related to chamber pressure, this result is still sufficiently encouraging to warrant further investigation of the type. As importantly, the data derived from the experiments, including performance analysis and wall pressure variations in time and space, are now being made available to the wider academic community, something which for commercial reasons appears to be a unique occurrence for this type of nozzle.

  12. Space Shuttle separate-surface control-system study

    NASA Technical Reports Server (NTRS)

    Brown, L. W.; Montgomery, R. C.

    1984-01-01

    A control system concept is presented that produces proportional control of yaw moment for the space shuttle from early entry to Mach 2 with only software modifications of the vehicle. It uses separate deflections of the inboard and outboard elevon surfaces and is evaluated, by determining the maximum static yawing moment available by considering the deflection limits of the elevon surfaces. A proportional moment slightly in excess of that produced by the most effective reaction control system (RCS) jet for yaw control can be obtained. In addition to the static moment study, a control law is designed which is intended to produce desired flying qualities.

  13. One dimensional CdS nanowire@TiO2 nanoparticles core-shell as high performance photocatalyst for fast degradation of dye pollutants under visible and sunlight irradiation.

    PubMed

    Arabzadeh, Abbas; Salimi, Abdollah

    2016-10-01

    In this study, one-dimensional CdS nanowires@TiO2 nanoparticles core-shell structures (1D CdS NWs@TiO2 NPs) were synthesized by a facile wet chemical-solvothermal method. The different aspects of the properties of CdS NWs@TiO2 NPs were surveyed by using a comprehensive range of characterization techniques including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV-vis spectroscopy, scanning electron microscopy (SEM), fluorescence spectroscopy, energy dispersive X-ray spectroscopy (EDX), Cyclic Voltammetry (CV) and amperometry. The as-prepared nanostructure was applied as an effective photocatalyst for degradation of methyl orange (MO), methylene blue (MB) and rhodamine B (Rh B) under visible and sunlight irradiation. The results indicated significantly enhanced photocatalytic activity of CdS NWs@TiO2 NPs for degradation of MO, MB and Rh B compared to CdS NWs. The enhanced photocatalytic activity could be attributed to the enhanced sunlight absorbance and the efficient charge separation of the formed heterostructure between CdS NWs and TiO2. The results showed that MO, Rh B and MB were almost completely degraded after 2, 2 and 3min of exposure to sunlight, respectively; while under visible light irradiation (3W blue LED lamp) the dyes were decomposed with less half degradation rate. The catalytic activity was retained even after three degradation cycles of organic dyes, demonstrating that the proposed nanocomposite can be effectively used as efficient photocatalyst for removal of environmental pollutions caused by organic dyes under sunlight irradiation and it could be an important addition to the field of wastewater treatment. We hope the present study may open a new window of such 1-D semiconductor nanocomposites to be used as visible light photocatalysts in the promising field of organic dyes degradation. PMID:27348482

  14. Crossed, Small-Deflection Energy Analyzer for Wind/Temperature Spectrometer

    NASA Technical Reports Server (NTRS)

    Herrero, Federico A.; Finne, Theodore T.

    2010-01-01

    Determination of neutral winds and ion drifts in low-Earth-orbit missions requires measurements of the angular and energy distributions of the flux of neutrals and ions entering the satellite from the ram direction. The magnitude and direction of the neutral-wind (or ion-drift) determine the location of the maximum in the angular distribution of the flux. Knowledge of the angle of maximum flux with respect to satellite coordinates (pointing) is essential to determine the wind (or ion-drift) vector. The crossed Small-Deflection Energy Analyzer (SDEA) spectrometer (see Figure 1) occupies minimal volume and consumes minimal power. Designed for upper atmosphere/ionosphere investigations at Earth altitudes above 100 km, the spectrometer operates by detecting the angular and energy distributions of neutral atoms/molecules and ions in two mutually perpendicular planes. In this configuration, the two detection planes actually cross at the spectrometer center. It is possible to merge two SDEAs so they share a common optical axis and alternate measurements between two perpendicular planes, and reduce the number of ion sources from two to one. This minimizes the volume and footprint significantly and reduces the ion source power by a factor of two. The area of the entrance aperture affects the number of ions detected/second and also determines the energy resolution. Thermionic emitters require heater power of about 100 mW to produce 1 mA of electron beam current. Typically, electron energy is about 100 eV and requires a 100-V supply for electron acceleration to supply an additional 100 mW of power. Thus, ion source power is at most 200 mW. If two ion sources were to be used, the ion source power would be, at most, 400 mW. Detector power, deflection voltage power, and microcontroller and other functions require less than 150 mW. A WTS (wind/ temperature spectrometer) with two separate optical axes would consume about 650 mW, while the crossed SDEA described here consumes about

  15. Separation techniques.

    PubMed

    Duke, T

    1998-10-01

    The past two years have seen continued development of capillary electrophoresis methods. The separation performance of flowable sieving media now equals, and in some respects exceeds, that provided by gels. The application of microfabrication techniques to separation science is gaining pace. There is a continuing trend towards miniaturization and integration of separation with preparative or analytical steps. Innovative separation methods based on microfabrication technology include electrophoresis in purpose-designed molecular sieves, dielectric, trapping using microelectrodes, and force-free motion in Brownian ratchets. PMID:9818184

  16. Orbital and mission planning constraints for the deflection of NEOs impacting on Earth

    NASA Astrophysics Data System (ADS)

    Carusi, Andrea; D'Abramo, Germano; Valsecchi, Giovanni B.

    2008-04-01

    This paper is the third in a series. Paper 1 presented the results of numerical modeling of deflections of NEOs in route of collision with the Earth. The model was applied to a variety of dynamical cases including both asteroidal and cometary NEOs. Paper 2 introduced the concept of "distributed deflection," i.e., the possibility to provide the Δ V necessary to deflect an object with a succession of maneuvers each of which would have been insufficient per se to obtain the desired result. In both papers no assumptions were made on the physical composition and structure of the NEO, nor on the details of the possible deflection maneuvers from the point of view of mission analysis. Moreover, Δ V-plots were computed assuming only along-track impulses (both in the positive and negative directions), because it is easy to demonstrate that in general this is energetically the most favorable configuration. Also in the present paper no assumptions were made on the physical composition and structure of the NEO, even if order of magnitude considerations are made on the physical feasibility of a deflection, in terms of the internal strength of the NEO. We present here the results of an investigation on the mission requirements necessary to deflect an object (or contribute to a succession of deflecting maneuvers) in terms of accessibility of the spacecraft terminal orbit from Earth with the current launchers.

  17. Compact E ×B mass separator for heavy ion beamsa)

    NASA Astrophysics Data System (ADS)

    Wada, M.; Hashino, T.; Hirata, F.; Kasuya, T.; Sakamoto, Y.; Nishiura, M.

    2008-02-01

    A compact E ×B mass separator that deflects beam by 30° has been designed and built to prove its principle of operation. The main part of the separator is contained in a shielding box of 11cm long, 9cm wide, and 1.5cm high. An electromagnet of 7cm pole diameter produced variable magnetic field in the mass separation region instead of a couple of permanent magnets which is to be used in the final design. The experimental result agreed well with the theoretical prediction, and larger mass ions is bent with less magnetic field with the aid of the deflection electric field. The reduction in resolving power for mass separation due to the deflection electric field has been investigated experimentally.

  18. MoS2/reduced graphene oxide hybrid with CdS nanoparticles as a visible light-driven photocatalyst for the reduction of 4-nitrophenol.

    PubMed

    Peng, Wen-chao; Chen, Ying; Li, Xiao-yan

    2016-05-15

    Photocatalytic reduction of nitroaromatic compounds to aromatic amines using visible light is an attractive process that utilizes sunlight as the energy source for the chemical conversions. Herewith we synthesized a composite material consisting of CdS nanoparticles grown on the surface of MoS2/reduced graphene oxide (rGO) hybrid as a novel photocatalyst for the reduction of 4-nitrophenol (4-NP). The CdS-MoS2/rGO composite is shown as a high-performance visible light-driven photocatalyst. Even without a noble-metal cocatalyst, the catalyst exhibited a great activity under visible light irradiation for the reduction of 4-NP to much less toxic 4-aminophenol (4-AP) with ammonium formate as the sacrificial agent. Composite CdS-0.03(MoS2/0.01rGO) was found to be the most effective photocatalyst for 4-NP reduction. The high photocatalytic performance is apparently resulted from the synergetic functions of MoS2 and graphene in the composite, i.e. the cocatalysts serve as both the active adsorption sites for 4-NP and electron collectors for the separation of electron-hole pairs generated by CdS nanoparticles. The laboratory results show that the CdS-MoS2/rGO composite is a low-cost and stable photocatalyst for effective reduction and detoxification of nitroaromatic compounds using solar energy. PMID:26894290

  19. Vertically aligned TiO2/(CdS, CdTe, CdSTe) core/shell nanowire array for photoelectrochemical hydrogen generation

    NASA Astrophysics Data System (ADS)

    Ai, Guanjie; Mo, Rong; Xu, Hang; Chen, Qiong; Yang, Sui; Li, Hongxing; Zhong, Jianxin

    2015-04-01

    Type-II TiO2/CdS, TiO2/CdTe and TiO2/CdSTe heterostructured core/shell nanowire arrays (NWAs) on FTO substrates are synthesized via physical vapor deposition of CdS, CdTe and the alloyed CdSTe layer onto the hydrothermally pre-grown TiO2 NWAs. Their morphologies, microstructures, and optical properties are characterized in detail. As photoanodes for photoelectrochemical (PEC) hydrogen generation, the ternary CdSTe alloy sensitized TiO2 NWAs exhibits a photocurrent density of 4.52 mA cm-2 under 1 sun illumination at 0.4261 V vs. RHE, much higher than that of the TiO2/CdS (2.97 mA cm-2) and TiO2/CdTe (0.46 mA cm-2) electrodes. This highest photocurrent density level of the alloy TiO2/CdSTe electrode is attributed to the broadened light absorption range and enhanced charge separation efficiency according to the optical and electrochemical impedance spectra investigation. Our result implies a promising application of CdSTe sensitized TiO2 photoelectrode in PEC cell and other photoelectronic devices.

  20. Flexible endoscope deflectability: changes using a variety of working instruments and laser fibers.

    PubMed

    Poon, M; Beaghler, M; Baldwin, D

    1997-08-01

    To measure the effects of different working instruments and holmium laser fibers on the deflectability in a variety of actively deflectable flexible endoscopes, a benchtop study was performed. The endoscopes studied were the Storz 7.5 flexible ureteroscope, the AUR-7 and AUR-9 flexible ureteroscopes (Circon-ACMI), a prototype Mitsubishi flexible ureteroscope (Mitsubishi Optics, Inc.), the ACN flexible cystoscope (Circon-ACMI), and the Storz flexible cystoscope. Working instruments included 1.6F (Wolf) and 1.9F (Microvasive) electrohydraulic lithotripsy (EHL) probes, 1.9F two-prong graspers and Bagley baskets, 2.4F Segura and helical baskets (Microvasive), 3.0F Segura basket, and 200- and 365-micron holmium laser fibers (Xintec). In ureteroscopes, the effect of 1.6F and 1.9F EHL probes ranged from having no effect in the Xintec 6,000, to decreasing deflection by 30 degrees in the AUR-7. Working instruments that were 2.4F or greater reduced deflection from 33 degrees to 93 degrees. Better deflectability was noted with the 200-micron holmium laser fiber than with the 365-micron fiber. The diameter of the working instrument did not affect deflectability as severely in cystoscopes. No significant differences in deflection existed between the 365-micron and 200-micron fibers in the flexible nephroscopes tested. In general, working instruments less than 2.4F and the 200-micron laser fiber have little effect on deflectability compared with working instruments 2.4F or larger and the 365-micron fiber. Flexible cystoscopes, with their larger working channels and stronger deflection cables, are affected less by working instrument diameter than are flexible ureteroscopes. PMID:9376842

  1. MIS diode structure in As/+/ implanted CdS

    NASA Technical Reports Server (NTRS)

    Hutchby, J. A.

    1977-01-01

    Structure made by As implantation of carefully prepared high-conductivity CdS surfaces followed by Pt deposition and 450 C anneal display rectifying, although substantially different, I-V characteristics in the dark and during illumination with subband-gap light. Structures prepared in the same way on an unimplanted portion of the substrate have similar I-V characteristics, except that the forward turnover voltage for an illuminated unimplanted diode is much smaller than that for an implanted diode. It is suggested that the charge conduction in both structures is dominated by hole and/or electron tunneling through a metal-semiconductor potential barrier. The tunneling processes appear to be quite sensitive to subband-gap illumination, which causes the dramatic decreases of turnover voltages and apparent series resistances. The difference in turnover voltage appears to be caused by interface states between the Pt electrode and the implanted layer, which suggests a MIS model.

  2. Broad spectral response photodetector based on individual tin-doped CdS nanowire

    NASA Astrophysics Data System (ADS)

    Zhou, Weichang; Peng, Yuehua; Yin, Yanling; Zhou, Yong; Zhang, Yong; Tang, Dongsheng

    2014-12-01

    High purity and tin-doped 1D CdS micro/nano-structures were synthesized by a convenient thermal evaporation method. SEM, EDS, XRD and TEM were used to examine the morphology, composition, phase structure and crystallinity of as-prepared samples. Raman spectrum was used to confirm tin doped into CdS effectively. The effect of impurity on the photoresponse properties of photodetectors made from these as-prepared pure and tin-doped CdS micro/nano-structures under excitation of light with different wavelength was investigated. Various photoconductive parameters such as responsivity, external quantum efficiency, response time and stability were analyzed to evaluate the advantage of doped nanowires and the feasibility for photodetector application. Comparison with pure CdS nanobelt, the tin-doped CdS nanowires response to broader spectral range while keep the excellect photoconductive parameters. Both trapped state induced by tin impurity and optical whispering gallery mode microcavity effect in the doped CdS nanowires contribute to the broader spectral response. The micro-photoluminescence was used to confirm the whispering gallery mode effect and deep trapped state in the doped CdS nanowires.

  3. Broad spectral response photodetector based on individual tin-doped CdS nanowire

    SciTech Connect

    Zhou, Weichang E-mail: dstang@hunnu.edu.cn; Peng, Yuehua; Yin, Yanling; Zhou, Yong; Zhang, Yong; Tang, Dongsheng E-mail: dstang@hunnu.edu.cn

    2014-12-15

    High purity and tin-doped 1D CdS micro/nano-structures were synthesized by a convenient thermal evaporation method. SEM, EDS, XRD and TEM were used to examine the morphology, composition, phase structure and crystallinity of as-prepared samples. Raman spectrum was used to confirm tin doped into CdS effectively. The effect of impurity on the photoresponse properties of photodetectors made from these as-prepared pure and tin-doped CdS micro/nano-structures under excitation of light with different wavelength was investigated. Various photoconductive parameters such as responsivity, external quantum efficiency, response time and stability were analyzed to evaluate the advantage of doped nanowires and the feasibility for photodetector application. Comparison with pure CdS nanobelt, the tin-doped CdS nanowires response to broader spectral range while keep the excellect photoconductive parameters. Both trapped state induced by tin impurity and optical whispering gallery mode microcavity effect in the doped CdS nanowires contribute to the broader spectral response. The micro-photoluminescence was used to confirm the whispering gallery mode effect and deep trapped state in the doped CdS nanowires.

  4. Carbon-assisted morphological manipulation of CdS nanostructures and their cathodoluminescence properties

    SciTech Connect

    Zhang Meng; Zhai, Tianyou; Wang Xi; Liao Qing; Ma Ying; Yao, Jiannian

    2009-11-15

    CdS nanostructures with different morphologies and sizes were successfully fabricated through a facile and effective carbon-assisted thermal evaporation method. Through simply changing the positions of silicon substrates, the temperatures and the effects of carbon in different zones were modified, and thus the morphologies of CdS nanostructures were varied from multipods to nanobrushes to nanocups. These nanostructures were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectrometry (EDS), X-ray powder diffraction (XRD) and Raman spectroscopy. Cathodoluminescence (CL) measurement shows that the as-grown CdS nanostructures display different luminescent properties. CdS multipods and nanocups show mainly green emission centered at {approx}496 nm. However, nanobrushes exhibit predominant red emission band peaking at {approx}711 nm. These interesting results show that carbon not only affected the growth process but also influenced the properties of CdS nanostructures. - Graphical abstract: A facile and effective carbon-assisted thermal evaporation method is explored to synthesize CdS multipods, nanobrushes and nanocups. These CdS nanostructures display very different optical properties.

  5. Hexagonal pencil-like CdS nanorods: Facile synthesis and enhanced visible light photocatalytic performance

    NASA Astrophysics Data System (ADS)

    An, Liang; Wang, Guanghui; Zhao, Lei; Zhou, Yong; Gao, Fang; Cheng, Yang

    2015-07-01

    In the present study, hexagonal pencil-like CdS nanorods have been successfully synthesized through a typical facile and economical one-step hydrothermal method without using any surfactant or template. The product was characterized by X-ray powder diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and energy dispersive analysis of X-ray (EDX). The results revealed that the prepared CdS photocatalyst consisted of a large quantity of straight and smooth solid hexagonal nanorods and a few nanoparticles. The photocatalytic activities of CdS nanorods and commercial CdS powders were investigated by the photodegradation of Orange II (OII) in aqueous solution under visible light, and the CdS nanorods presented the highest photocatalytic activity. Its photocatalytic efficiency enhancement was attributed to the improved transmission of photogenerated electron-hole pairs in the CdS nanostructures. The present findings may provide a facile approach to synthesize high efficient CdS photocatalysts.

  6. Deflection, spraying, and induced scattering of intense laser beams in plasmas

    SciTech Connect

    Kruer, W.L.

    1996-09-01

    Investigations into laser beam spraying, deflection, and induced scattering in plasmas are presented. Recent calculations and experiments on beam spraying due to filamentation are discussed. A simple model is presented for an enhanced beam deflection associated with nearly sonic plasma flow transverse to the beam. This model provides useful insights on the laser beam deflection, its scaling and the importance of self-consistent profile modifications. Finally, some discussion is given of recent experiments demonstrating the interplay between stimulated.Raman and Brillouin scattering.

  7. Deflection of a hyperbaric plasma arc in a transverse magnetic field

    SciTech Connect

    Richardson, I.M.

    1993-12-31

    Results are presented concerning the influence of operating parameters on the susceptibility of the plasma arc to deflection by an externally generated transverse magnetic field. Arc deflection susceptibility is found to increase rapidly with rising ambient pressure and is significantly greater for the free burning TIG arc compared with the weakly constricted (soft) plasma arc. In agreement with previously published work, it has been shown that for small amplitude deflections the arc column behaves in a manner analogous to a solid body. However, above a critical field strength the structure of the column undergoes a significant change characterized by a rapid deterioration in stability; mechanisms for this behavior are discussed.

  8. Cold beam of isotopically pure Yb atoms by deflection using 1D-optical molasses

    NASA Astrophysics Data System (ADS)

    Rathod, K. D.; Singh, P. K.; Natarajan, Vasant

    2014-09-01

    We demonstrate generation of an isotopically pure beam of laser-cooled Yb atoms by deflection using 1D-optical molasses. Atoms in a collimated thermal beam are first slowed using a Zeeman Slower. They are then subjected to a pair of molasses beams inclined at $45^\\circ$ with respect to the slowed atomic beam. The slowed atoms are deflected and probed at a distance of 160 mm. We demonstrate selective deflection of the bosonic isotope $^{174}$Yb, and the fermionic isotope $^{171}$Yb. Using a transient measurement after the molasses beams are turned on, we find a longitudinal temperature of 41 mK.

  9. RF Design of Normal Conducting Deflecting Structures for the Advanced Photon Source

    SciTech Connect

    Dolgashev, V.A.; Borland, Michael; Waldschmidt, Geoff; /Argonne

    2007-11-07

    Use of normal conducting deflecting structures for production of short x-ray pulses is now under consideration at Argonne's Advanced Photon Source (APS). The structures have to produce up to 4 MV maximum deflection per pair of structures with a 1 kHz repetition rate. At the same time, the structures should not cause deterioration of beam properties in the APS ring. Following these requirements, we proposed 2815 MHz standing wave deflecting structures with heavy wakefield damping. In this paper we discuss design considerations and present our current design.

  10. Light deflection with torsion effects caused by a spinning cosmic string

    NASA Astrophysics Data System (ADS)

    Jusufi, Kimet

    2016-06-01

    Using a new geometrical method introduced by Werner, we find the deflection angle in the weak limit approximation by a spinning cosmic string in the context of the Einstein-Cartan (EC) theory of gravity. We begin by adopting the String-Randers optical metric, then we apply the Gauss-Bonnet theorem to the optical geometry and derive the leading terms of the deflection angle in the equatorial plane. Calculation shows that light deflection is affected by the intrinsic spin of the cosmic string and torsion.

  11. A finite element large deflection random response of a pipe containing fluid flow

    NASA Technical Reports Server (NTRS)

    Chiang, C. K.

    1991-01-01

    A finite element approach is developed for beam type pipes undergoing large deflections subjected to random loadings. The influence of fluid velocity on the random response is investigated. The root-mean-square (rms) deflections and frequencies for different sound spectrum level values are determined for pipes with both ends either simply supported or clamped. The required number of modes to achieve accurate rms deflections is studied. The prediction of fatigue life is then based on the maximum rms stress. This analytical investigation will help to broaden the basic understanding of the role of fluid flow within structures subjected to random excitations.

  12. Effect of lateral size and thickness on the electronic structure and optical properties of quasi two-dimensional CdSe and CdS nanoplatelets

    NASA Astrophysics Data System (ADS)

    Bose, Sumanta; Song, Zhigang; Fan, W. J.; Zhang, D. H.

    2016-04-01

    The effect of lateral size and vertical thickness of CdSe and CdS nanoplatelets (NPLs) on their electronic structure and optical properties are investigated using an effective-mass envelope function theory based on the 8-band k ṡ p model with valence force field considerations. Volumetrically larger NPLs have lower photon emission energy due to limited quantum confinement, but a greater transition matrix element (TME) due to larger electron-hole wavefunction overlap. The optical gain characteristics depend on several factors such as TME, Fermi factor, carrier density, NPL dimensions, material composition, and dephasing rate. There is a red shift in the peak position, more so with an increase in thickness than lateral size. For an increasing carrier density, the gain spectrum undergoes a slight blue shift due to band filling effect. For a fixed carrier density, the Fermi factor is higher for volumetrically larger NPLs and so is the difference between the quasi-Fermi level separation and the effective bandgap. The transparency injection carrier density (and thus input current density threshold) is dimension dependent and falls for volumetrically larger NPLs, as they can attain the requisite exciton count for transparency with a relatively lower density. Between CdSe and CdS, CdSe has lower emission energy due to smaller bandgap, but a higher TME due to lower effective mass. CdS, however, has a higher so hole contribution due to a lower spin-orbit splitting energy. Both CdSe and CdS NPLs are suitable candidates for short-wavelength LEDs and lasers in the visible spectrum, but CdSe is expected to exhibit better optical performance.

  13. Model of phase distribution of hydrophobic organic chemicals in cyclodextrin-water-air-solid sorbent systems as a function of salinity, temperature, and the presence of multiple CDs

    NASA Astrophysics Data System (ADS)

    Blanford, W. J.

    2013-12-01

    Environmental and other applications of cyclodextrins (CD) often require usage of high concentra- tion aqueous solutions of derivatized CDs. In an effort to reduce the costs, these studies also typically use technical grades where the purity of the CD solution and the degree of substitution has not been reported. Further, this grade of CD often included high levels of salt and it is commonly applied in high salinity systems. The mathematical models for water and air partitioning coefficients of hydrophobic organic chemicals (HOC) with CDs that have been used in these studies under-estimate the level of HOC within CDs. This is because those models (1) do not take into account that high concentrations of CDs result in significantly lower levels of water in solution and (2) they do not account for the reduction in HOC aqueous solubility due to the presence of salt. Further, because they have poor knowledge of the CD molar concentration in their solu- tions, it is difficult to draw comparisons between studies. Herein is developed a mathematical model where cyclo- dextrin is treated as a separate phase whose relative volume is calculated from its apparent molar volume in solution and the CD concentration of the solution. The model also accounts for the affects of temperature and the presence of salt in solution through inclusion of modified versions of the Van't Hoff and Setschenow equations. With these capabilities, additional equations have been developed for calculating HOC phase distribution in air-water-CD-solid sorbent systems for a single HOC and between water and CD for a system containing multiple HOCs as well as multiple types of cyclodextrin.

  14. High aspect ratio CdS nanowires synthesized in microemulsion system

    SciTech Connect

    Fu Xun . E-mail: fuxun@qust.edu.cn; Wang Debao; Wang Jing; Shi Huaqiang; Song Caixia

    2004-10-04

    CdS nanowires with typical length more than 8 {mu}m and width of 30 nm on average have been successfully synthesized through Cd(NO{sub 3}){sub 2} reacting with CS{sub 2} and ethylenediamine in microemulsion system of sodium dodecylbenzene sulfonate (SBDS). The microstructures of the as-synthesized CdS nanowires were characterized using XRD, transmission electron microscopy (TEM) and HRTEM. The possible formation mechanism was discussed. The morphologies of CdS sample strongly depend on the concentration of surfactant in solutions.

  15. Preparation and Structural Analysis of CdS Nanoparticle Embedded Polyurethane Nanocomposites

    SciTech Connect

    Indolia, Ajay Pal; Kumar, Purushottam; Gaur, M. S.

    2011-07-15

    Polymer nanocomposite samples of different weight ratio of CdS were developed by solution embedding of nanoparticles in polyurethane. XRD and Scanning Electron Microscopy (SEM) were used to understand the structural properties of polymer nanocomposite samples. SEM micrograph demonstrates the dispersion of CdS nanoparticles in polymer matrix. It has been observed that crystallinity of PU decreases with increase in concentration of CdS nanoparticles. The XRD data show the characteristic peaks of nanoparticles (i.e.CdS) in nanocomposite samples, which confirm the nanostructure formation in polymer matrix.

  16. Electrochemical template-assisted fabrication of CdS micro/nanostructures

    NASA Astrophysics Data System (ADS)

    Jindal, Zinki; Verma, N. K.

    2009-10-01

    One-dimensional (1D) cadmium sulphide (CdS) nanostructures, including micro/nanorods, and nanostructures resembling flowers and cactus have been synthesized by electrochemical template deposition technique, using polycarbonate membranes, by controlling various reaction parameters. These 1D CdS nanostructures were characterized structurally through the X-ray diffraction (XRD) studies and morphologically through scanning electron microscopy (SEM). It was found that apart from the dimensions of the pores of the templates, the geometrical morphologies of the CdS 1D nanostructures were significantly influenced by the synthesizing parameters also. The optical characterization has been done by UV-visible absorption and room-temperature photoluminescence (PL) studies.

  17. Evidence of reaction rate influencing cubic and hexagonal phase formation process in CdS nanocrystals

    NASA Astrophysics Data System (ADS)

    Deka, Kuldeep; Kalita, M. P. C.

    2016-05-01

    CdS nanocrystals are synthesized by co-precipitation method using 2-mercaptoethanol (ME) as capping agent. Cubic, hexagonal and their mixture are obtained by varying the ME concentration. Lower (higher) ME concentration results in cubic (hexagonal) phase. The crystallite sizes are in the range 3-7 nm. Increase in ME concentration lead to lower reaction rate between Cd2+ and S2- of the precursors, and slower reaction rate is found to favor hexagonal phase formation over the cubic one in CdS nanocrystals. Role of reaction rate in the phase formation process provides a way to synthesize CdS nanocrystals in desired crystal phase.

  18. CdS loaded on coal based activated carbon nanofibers with enhanced photocatalytic property

    NASA Astrophysics Data System (ADS)

    Guo, Jixi; Guo, Mingxi; Jia, Dianzeng; Song, Xianli; Tong, Fenglian

    2016-08-01

    The coal based activated carbon nanofibers (CBACFs) were prepared by electrospinning a mixture of polyacrylonitrile (PAN) and acid treated coal. Cadmium sulfide (CdS) nanoparticles loaded on CBACFs were fabricated by solvothermal method. The obtained samples were characterized by FESEM, TEM, and XRD. The results reveal that the CdS nanoparticles are homogeneously dispersed on the surfaces of CBACFs. The CdS/CBACFs nanocomposites exhibited higher photoactivity for photodegradation of methyl blue (MB) under visible light irradiation than pure CdS nanoparticles. CBACFs can be used as low cost support materials for the preparation of nanocomposites with high photocatalytic activity.

  19. Synthesis of CdS nanoparticles for photocatalytic application of methyleneblue degradation

    SciTech Connect

    Muthuraj, V.; Umadevi, M.; Sankarasubramanian, K.; Kajamuhideen, M. S.

    2014-04-24

    CdS nanoparticles were prepared by the reaction of cadmium acetate with thiourea in the presence and absence of methylene blue dye (MB). The nanoparticles were characterized by, XRD, FT-IR, UV-Vis. XRD study shows the presence of hexagonal phase for the nanoparticles whereas in case of the bulk samples only the hexagonal phase is observed. Fourier transform infrared spectroscopy (FT-IR) showed a strong interaction of methyl groups with CdS nanoparticles. The degradation of methylene blue was analysed using UV-Vis absorbance spectrum. Thus the results authenticate that methylene blue dye influences the structural and optical properties of the CdS nanoparticles.

  20. Random lasing characteristics in dye-doped semiconductor CdS nanoparticles

    NASA Astrophysics Data System (ADS)

    Li, L. W.

    2016-01-01

    A new strategy to obtain random lasing from semiconductor CdS nanoparticles is presented. A device is prepared with dye (DCM) solution containing CdS NPs. Good lasing behavior is reached and the multiple light scattering process is responsible for lasing generation. We also manage to show that the lasing modes and output intensity exhibit angular dependence. The result indicates that CdS nanoparticles can be used as ideal microlaser material in future semiconductor laser devices. Supported by the Doctoral Science Research Start-up Funding of GuiZhou Normal University No. 11904-0514162.

  1. PVP capped CdS nanoparticles for UV-LED applications

    SciTech Connect

    Sivaram, H.; Selvakumar, D.; Jayavel, R.

    2015-06-24

    Polyvinlypyrrolidone (PVP) capped cadmium sulphide (CdS) nanoparticles are synthesized by wet chemical method. The powder X-ray diffraction (XRD) result indicates that the nanoparticles are crystallized in cubic phase. The optical properties are characterized by UV-Vis absorption. The morphology of CdS nanoparticles are studied using Scanning electron microscope (SEM). The thermal behavior of the as prepared nanoparticles has been examined by Thermo gravimetric analysis (TGA). The optical absorption study of pvp capped CdS reveal a red shift confirms the UV-LED applications.

  2. Superior photoluminescence and photocatalytic activity of CdS (core)-SiO2 (shell) nanostructures obtained by CdS photoetching and Au deposition.

    PubMed

    Gupta, Nidhi; Pal, Bonamali

    2013-07-01

    Core-shell morphology of silica (SiO2) coated CdS nanocomposites (SiO2@CdS) of different shapes have been made for better stability, luminescence and photochemical activity of CdS nanoparticles. A thin layer (thickness 1-1.4 nm) of SiO2 shell is deposited over CdS nanorods (CdS-NR) of aspect ratio = 21 and CdS nanospheres (CdS-NS) of size 6-8 nm by alkyl silane agents. Synthesized nanostructures were characterized by diffuse reflectance spectra, HR-TEM, BET surface measurement, LB surface film, and absorption and photoluminescence analysis. Photoetching (PE) of CdS core led to blue shift of the absorbance onset of SiO2@CdS-NR along with the appearance of an exciton band at 485 nm due to the quantum confinement effect. Photodissolution of CdS core shifts the band gap energy from initial 2.4 to 2.6 eV for CdS-NR and 2.5 to 2.67 eV for CdS-NS. TEM images reveal the increase in aspect ratio of NR from 21 to 31 and decrease in the spherical core to 2.5 nm from 6-8 nm after PE. Photoetched SiO2@CdS-NC displayed highly intense fluorescence emission (SiO2@CdS-NS > SiO2@CdS-NR) than unetched SiO2@CdS-NC at 488 nm corresponding to band edge position. The Au (0.5 wt.%) deposition onto photoetched SiO2@CdS-NR(PE) composites highly enhanced the fluorescence intensity in comparison to 1 wt.% of Au and Ag loading. SiO2@CdS-NC(PE) displayed improved photocatalytic activity during benzaldehyde photooxidation under UV (125 W, Hg-arc, 10.4 mW/cm2) irradiation. Silica coating onto CdS particles improves the photostability and photoactivity of CdS upon long UV irradiation. PMID:23901532

  3. Comparison of electromagnetic, thermal and mechanical calculations with rf test results in rf-dipole deflecting/crabbing cavities

    SciTech Connect

    Park, HyeKyoung; De Silva, Subashini U.; Delayen, Jean R.

    2013-12-01

    The current requirements of higher gradients and strict dimensional constraints in the emerging applications have required the designing of compact deflecting and crabbing rf structures. The superconducting rf-dipole cavity is one of the first novel compact designs with attractive properties such as higher gradients, higher shunt impedance and widely separated higher order modes. The recent tests performed on proof-of-principle designs of the rf-dipole geometry at 4.2 K and 2.0 K in the vertical test area at Jefferson Lab have proven the designs to achieve higher gradients with higher intrinsic quality factors and easily processed multipacting conditions. The cavity characteristics, such as pressure sensitivity and Lorentz force detuning, were studied using ANSYS before the fabrication. These characteristics were measured during the cavity test. The comparison between the simulation and the measurement provides insight how the simulation can be used for design and fabrication of future cavities.

  4. Pressure distributions induced by elevon deflections on swept wings and adjacent end-plate surfaces at Mach 6

    NASA Technical Reports Server (NTRS)

    Kaufman, L. G., II; Johnson, C. B.

    1977-01-01

    Surface pressure distributions are presented for regions where three-dimensional separated flow effects are prominent on swept-wing-elevon-end-plate models of 0 degree, 50 degree, and 70 degree sweepback, and with 0 degree, 10 degree, 20 degree, and 30 degree elevon deflections. Surface-oil-flow photographs and pressure distributions on the flat-plate wing, elevon, and end-plate surfaces are presented for numerous geometric variations, including various spacings between the elevon and the end plate, with and without a tip fin. The data, for a free-stream Mach number of 6 and a wing-root-chord Reynolds number of 20 x 10 to the sixth power, reveal considerably larger regions of elevon induced loads on the adjacent end-plate surface than would be anticipated by using inviscid flow analyses.

  5. Char separator

    DOEpatents

    Matthews, Francis T.

    1979-01-01

    Particulates removed from the flue gases produced in a fluidized-bed furnace are separated into high-and low-density portions. The low-density portion is predominantly char, and it is returned to the furnace or burned in a separate carbon burnup cell. The high-density portion, which is predominantly limestone products and ash, is discarded or reprocessed. According to another version, the material drained from the bed is separated, the resulting high-and low-density portions being treated in a manner similar to that in which the flue-gas particulates are treated.

  6. CENTRIFUGAL SEPARATORS

    DOEpatents

    Skarstrom, C.

    1959-03-10

    A centrifugal separator is described for separating gaseous mixtures where the temperature gradients both longitudinally and radially of the centrifuge may be controlled effectively to produce a maximum separation of the process gases flowing through. Tbe invention provides for the balancing of increases and decreases in temperature in various zones of the centrifuge chamber as the result of compression and expansions respectively, of process gases and may be employed effectively both to neutralize harmful temperature gradients and to utilize beneficial temperaturc gradients within the centrifuge.

  7. An oilspill trajectory analysis model with a variable wind deflection angle

    USGS Publications Warehouse

    Samuels, W.B.; Huang, N.E.; Amstutz, D.E.

    1982-01-01

    The oilspill trajectory movement algorithm consists of a vector sum of the surface drift component due to wind and the surface current component. In the U.S. Geological Survey oilspill trajectory analysis model, the surface drift component is assumed to be 3.5% of the wind speed and is rotated 20 degrees clockwise to account for Coriolis effects in the Northern Hemisphere. Field and laboratory data suggest, however, that the deflection angle of the surface drift current can be highly variable. An empirical formula, based on field observations and theoretical arguments relating wind speed to deflection angle, was used to calculate a new deflection angle at each time step in the model. Comparisons of oilspill contact probabilities to coastal areas calculated for constant and variable deflection angles showed that the model is insensitive to this changing angle at low wind speeds. At high wind speeds, some statistically significant differences in contact probabilities did appear. ?? 1982.

  8. Mission analysis for the ion beam deflection of fictitious asteroid 2015 PDC

    NASA Astrophysics Data System (ADS)

    Bombardelli, Claudio; Amato, Davide; Cano, Juan Luis

    2016-01-01

    Based on a hypothetical asteroid impact scenario proposed during the 2015 IAA Planetary Defense Conference (PDC), we study the deflection of fictitious asteroid 2015 PDC starting from ephemeris data provided by the conference organizers. A realistic mission scenario is investigated that makes use of an ion beam shepherd spacecraft as a primary deflection technique. The article deals with the design of a low-thrust rendezvous trajectory to the asteroid, the estimation of the propagated covariance ellipsoid and the outcome of an ion beam slow-push deflection starting from three worst case scenarios (impacts in New Delhi, Dhaka and Tehran). Displacing the impact point towards an extremely low-populated, easy-to-evacuate region, as opposed to full deflection, is found to be a more effective mitigation approach. Mission design, technical and political aspects are discussed.

  9. Observation-based Analysis of the Deflection of a Polar Crown Filament Eruption

    NASA Astrophysics Data System (ADS)

    Pomoell, J.; Vainio, R.; Kilpua, E. K. J.

    2010-03-01

    We utilize STEREO quadrature observations to study two CMEs that both originated from high-latitude source regions on 2 November 2008. The first CME was associated with a huge polar crown filament eruption and propagated initially clearly northward from the equator. However, the CME was quickly deflected towards the equator while propagating further out. On the other hand, the second CME, originating from an active region, did not deflect from its original northward trajectory. Based on the observations we discuss the role of the size of the erupting structure and the magnetic topology of the surrounding environment in deflecting CMEs and suggest that both a breakout initiation scenario as well as a tether-cutting initiation scenario can explain the observed deflective dynamics of the filament eruption.

  10. The effect of long-term deflection on permanent deformation of nickel-titanium archwires.

    PubMed

    Hudgins, J J; Bagby, M D; Erickson, L C

    1990-01-01

    The clinician must now consider the alloy along with cross-sectional shape and size when selecting archwires. The purpose of this study is to quantify permanent deformation after long-term deflection of available nickel-titanium archwires. Nine nickel-titanium, one beta-titanium and one stainless steel archwires, .016 inch round, were deflected into orthodontic brackets of simulated archform. One lateral incisor was positioned to yield a deflection of 5 mm in a lingual direction. After wire deactivation, deformation was measured at 1, 14, and 28 days. Two-way ANOVA and Tukey's critical difference tests were used to determine statistical differences. The nickel-titanium wires exhibited better springback characteristics and less permanent deformation than the stainless steel and TMA wires. Several wires increased deformation as deflection time increased. No clinically significant difference was found between presently available nickel-titanium wires in terms of permanent deformation, long- or short-term. PMID:2256566

  11. Experimental results for a two-dimensional supersonic inlet used as a thrust deflecting nozzle

    NASA Technical Reports Server (NTRS)

    Johns, Albert L.; Burstadt, Paul L.

    1984-01-01

    Nearly all supersonic V/STOL aircraft concepts are dependent on the thrust deflecting capability of a nozzle. In one unique concept, referred to as the reverse flow dual fan, not only is there a thrust deflecting nozzle for the fan and core engine exit flow, but because of the way the propulsion system operates during vertical takeoff and landing, the supersonic inlet is also used as a thrust deflecting nozzle. This paper presents results of an experimental study to evaluate the performance of a supersonic inlet used as a thrust deflecting nozzle for this reverse flow dual fan concept. Results are presented in terms of nozzle thrust coefficient and thrust vector angle for a number of inlet/nozzle configurations. Flow visualization and nozzle exit flow survey results are also shown.

  12. Deflection of slow light by magneto-optically controlled atomic media

    SciTech Connect

    Zhou, D. L.; Wang, R. Q.; Zhou, Lan; Yi, S.; Sun, C. P.

    2007-11-15

    We present a semiclassical theory for light deflection by a coherent {lambda}-type three-level atomic medium in an inhomogeneous magnetic field or an inhomogeneous control laser. When the atomic energy levels (or the Rabi coupling by the control laser) are position-dependent due to the Zeeman effect caused by the inhomogeneous magnetic field (or due to inhomogeneity of the control field profile), the spatial dependence of the refraction index of the atomic medium will result in an observable deflection of slow signal light when the electromagnetically induced transparency cancels medium absorption. Our theoretical approach based on Fermat's principle in geometrical optics not only provides a consistent explanation for the most recent experiment in a straightforward way, but also predicts the two-photon detuning dependent behaviors and larger deflection angles by three orders of magnitude for the slow signal light deflection by the atomic media in an inhomogeneous off-resonant control laser field.

  13. The use of a deflectable nose on a missile as a control device

    NASA Astrophysics Data System (ADS)

    Thompson, K. D.

    1981-05-01

    Wind tunnel tests have been carried out on a blunted ogive-cylinder with a deflectable nose at Mach numbers between 0.8 and 2.0. Although the results are subject to scale effects, it appears that the deflectable nose could find use as a missile control method. The results have been applied to two missile configurations. For a long slender missile the deflectable nose produces non-linear trim curves at subsonic speeds, approaching linearity at supersonic Mach numbers. Nevertheless, worth-while trimmed incidences can be achieved. Although a deflectable nose on a 105 mm shell at subsonic speeds produces only relatively small normal force coefficients at trim, the trim curves are linear. Furthermore, it appears that when used for terminal control significant deviations in shell impact point are attainable.

  14. Superconducting RF Deflecting Cavity Design and Prototype for Short X-ray Pulse Generation

    SciTech Connect

    Shi, Jiaru; Chen, H.; Tang, C.-X.; Cheng, Guangfeng; Ciovati, Gianluigi; Kneisel, Peter; Rimmer, Robert; Slack, Gary; Turlington, Larry; Wang, Haipeng; Li, D.; Nassiri, Alireza; Waldschmidt, G.J.

    2008-07-01

    Deflecting RF cavities are proposed to be used in generating short x-ray pulses (on ~1-picosecond order) at the Advanced Photon Source (APS) at Argonne National Laboratory (ANL)* using a novel scheme by Zholents**. To meet the required deflecting voltage, impedance budget from higher order, lower order and the same order modes (HOM, LOM and SOM) of the APS storage ring, extensive deflecting cavity design studies have been conducted with numerical simulations and cavity prototypes. In this paper, we report recent progress on a single cell S-band (2.8-GHz) superconducting deflecting cavity design with waveguide damping. A copper and a niobium prototype cavity were fabricated and tested, respectively to benchmark the cavity and damping designs. A new damping scheme has been proposed which provides stronger damping to both HOM and LOM by directly coupling to a damping waveguide on the cavity equator.

  15. Microfluidic immunomagnetic multi-target sorting--a model for controlling deflection of paramagnetic beads.

    PubMed

    Tsai, Scott S H; Griffiths, Ian M; Stone, Howard A

    2011-08-01

    We describe a microfluidic system that uses a magnetic field to sort paramagnetic beads by deflecting them in the direction normal to the flow. In the experiments we systematically study the dependence of the beads' deflection on bead size and susceptibility, magnet strength, fluid speed and viscosity, and device geometry. We also develop a design parameter that can aid in the design of microfluidic devices for immunomagnetic multi-target sorting. PMID:21677937

  16. Thermal stresses and deflections of cross-ply laminated plates using refined plate theories

    SciTech Connect

    Khdeir, A.A.; Reddy, J.N. Virginia Polytechnic Institute and State University, Blacksburg )

    1991-12-01

    Exact analytical solutions of refined plate theories are developed to study the thermal stresses and deflections of cross-ply rectangular plates. The state-space approach in conjunction with the Levy method is used to solve exactly the governing equations of the theories under various boundary conditions. Numerical results of the higher-order theory of Reddy for thermal stresses and deflections are compared with those obtained using the classical and first-order plate theories. 14 refs.

  17. Solutions of the heat conduction equation in multilayers for photothermal deflection experiments

    NASA Technical Reports Server (NTRS)

    Mcgahan, William A.; Cole, K. D.

    1992-01-01

    Analytical expressions for temperature and laser beam deflection in multilayer medium is derived using Green function techniques. The approach is based on calculation of the normal component of heat fluxes across the boundaries, from which either the beam deflections or the temperature anywhere in space can be found. A general expression for the measured signals for the case of four-quadrant detection is also presented and compared with previous calculations of detector response for finite probe beams.

  18. Design and Development of Superconducting Parallel-Bar Deflecting/Crabbing Cavities

    SciTech Connect

    Payagalage Subashini Uddi De Silva, Jean Delayen

    2012-07-01

    The superconducting parallel-bar cavity is a deflecting/crabbing cavity with attractive properties that is being considered for a number of applications. We present the designs of a 499 MHz deflecting cavity developed for the Jefferson Lab 12 GeV Upgrade and a 400 MHz crabbing cavity for the LHC High Luminosity Upgrade. Prototypes of these two cavities are now under development and fabrication.

  19. High-resolution and high-stability electromagnetic-deflection control system for EB lithography system

    NASA Astrophysics Data System (ADS)

    Nagata, Koji; Okumura, Masahide; Maio, Kenji; Fujii, Akira; Andoh, Hisashi; Morimura, Toshiyuki; Hayakawa, Hajime

    2001-08-01

    A stable high-resolution electromagnetic deflection control circuit for an electron-beam lithography (EBL) system has been developed. This deflection control circuit has enabled an EBL system to deal with a wide deflection area of 2.5-mm square having fine address units for a pattern placement of 1.25 nm. The deflection-control circuit consists of a new digital to analog converter (DAC) circuit, whose resolution is 21 bits, and a low-drift current-amplifier circuit. To achieve such high-stability and high-resolution, we had to develop a low noise-current cell structure for the new DAC circuit, because the output-signal noise of the DAC circuit is a major source of interference at the desired resolution. A local temperature control technique has been incorporated into the circuit to reduce fluctuations of the deflection control signal caused by ambient thermal variations. The low noise-current cell structure, which consists of multiple current buffers and low-pass filters, is placed between a constant current source circuit and a differential-switch circuit for each bit of the DAC circuit. The simulation results of the DAC circuit showed that the output-signal noise of the DAC circuit could be reduced to less than 0.4 nm rms, which is small enough to achieve the desired resolution. As the results of the experimentally evaluation of the deflection control circuit show, the total noise of the deflection-control signal obtained was less than 0.6 nm rms and the signal stability obtained was better than 0.3 nm rms. An evaluation of the performance of the new EBL system to which the new deflection control circuit was applied, showed that the critical-dimension accuracy obtained was better than 5 nm (3sigma) and the positioning accuracy obtained was better than 10 nm (3sigma) for the area controlled by electromagnetic deflector.

  20. Out-of-Plane Deflections as a Diagnostic Tool and Application to PEP-II

    SciTech Connect

    Venturini, Marco

    2001-02-01

    We derive simplified formulae that relate the ''out-of-plane'' beam-beam deflections of colliding e{sup +} and e{sup -} beams, to the off-diagonal entry of the {Sigma}-matrix expressing the convoluted beam sizes. These formulae can be used to fit measured deflection curves and extract information about the relative tilt angle of two colliding bunches in the transverse plane.

  1. Small deflection of a class of clamped thin plates using collocation

    NASA Technical Reports Server (NTRS)

    Worley, W. J.

    1977-01-01

    Equations are given for the optimization of a class of two-and three-dimensional structures. The application of existing analytical techniques to the response of thin clamped plates is described. The ratios of deflections to plate thickness are given for uniform transverse loads as well as for uniform plus linearly varying transverse loads. Deflections are presented at angular increments of 5 degrees and at radial increments of 0.1 of the radius.

  2. Stereoisomers Separation

    NASA Astrophysics Data System (ADS)

    Wieczorek, Piotr

    The use of capillary electrophoresis for enantiomer separation and optical purity determination is presented. The contents start with basic information about the nature of stereoizomers and the mechanism of enantioseparation using capillary electrophoresis techniques. The molecules to be separated show identical chemical structure and electrochemical behavior. Therefore, the chiral recognition of enantiomers is possible only by bonding to chiral selector and the separation based on very small differences in complexation energies of diastereomer complexes formed. This method is useful for this purpose due to the fact that different compounds can be used as chiral selectors. The mostly used chiral selectors like cyclodextrins, crown ethers, chiral surfactants, macrocyclic antibiotics, transition metal complexes, natural, and synthetic polymers and their application for this purpose is also discussed. Finally, examples of practical applications of electromigration techniques for enantiomers separation and determination are presented.

  3. Battery separator

    SciTech Connect

    Balouskus, R.A.; Feinberg, S.C.; Lundquist, J.T.; Lundsager, C.B.

    1980-09-23

    A battery separator and a method of forming the same is described. The separator has good electrical conductivity and a high degree of inhibition to dendrite formation, and is in the form of a thin sheet formed from a substantially uniform mixture of a thermoplastic rubber and a filler in a volume ratio of from about 1:0.15 to 1:0.6. The thermoplastic rubber is preferably a styrene/elastomer/styrene block copolymer.

  4. Comparison of Theory and Experiment on Aeroacoustic Loads and Deflections

    NASA Astrophysics Data System (ADS)

    Campos, L. M. B. C.; Bourgine, A.; Bonomi, B.

    1999-01-01

    The correlation of acoustic pressure loads induced by a turbulent wake on a nearby structural panel is considered: this problem is relevant to the acoustic fatigue of aircraft, rocket and satellite structures. Both the correlation of acoustic pressure loads and the panel deflections, were measured in an 8-m diameter transonic wind tunnel. Using the measured correlation of acoustic pressures, as an input to a finite-element aeroelastic code, the panel response was reproduced. The latter was also satisfactorily reproduced, using again the aeroelastic code, with input given by a theoretical formula for the correlation of acoustic pressures; the derivation of this formula, and the semi-empirical parameters which appear in it, are included in this paper. The comparison of acoustic responses in aeroacoustic wind tunnels (AWT) and progressive wave tubes (PWT) shows that much work needs to be done to bridge that gap; this is important since the PWT is the standard test means, whereas the AWT is more representative of real flight conditions but also more demanding in resources. Since this may be the first instance of successful modelling of acoustic fatigue, it may be appropriate to list briefly the essential ``positive'' features and associated physical phenomena: (i) a standard aeroelastic structural code can predict acoustic fatigue, provided that the correlation of pressure loads be adequately specified; (ii) the correlation of pressure loads is determined by the interference of acoustic waves, which depends on the exact evaluation of multiple scattering integrals, involving the statistics of random phase shifts; (iii) for the relatively low frequencies (one to a few hundred Hz) of aeroacoustic fatigue, the main cause of random phase effects is scattering by irregular wakes, which are thin on wavelength scale, and appear as partially reflecting rough interfaces. It may also be appropriate to mention some of the ``negative'' features, to which may be attached illusory

  5. Product separator

    DOEpatents

    Welsh, Robert A.; Deurbrouck, Albert W.

    1976-01-20

    A secondary light sensitive photoelectric product separator for use with a primary product separator that concentrates a material so that it is visually distinguishable from adjacent materials. The concentrate separation is accomplished first by feeding the material onto a vibratory inclined surface with a liquid flow, such as a wet concentrating table. Vibrations generally perpendicular to the stream direction of flow cause the concentrate to separate from its mixture according to its color. When the concentrate and its surrounding stream reach the recovery end of the table, a detecting device notes the line of color demarcation and triggers a signal if it differs from a normal condition. If no difference is noted nothing moves on the second separator. However, if a difference is detected in the constant monitoring of the color line's location, a product splitter and recovery unit normally positioned near the color line at the recovery end, moves to a new position. In this manner the selected separated concentrate is recovered at a maximum rate regardless of variations in the flow stream or other conditions present.

  6. Large deflection and rotation of Timoshenko beams with frictional end supports under three-point bending

    NASA Astrophysics Data System (ADS)

    Li, Dao-Kui; Li, Xian-Fang

    2016-08-01

    Three-point bending of a beam is studied based on the Timoshenko beam theory. Large deflection and large rotation of a beam resting on simple supports with friction are calculated for a concentrated force acting at the midspan. Using the Lagrangian kinematic relations, a system of non-linear differential equations are obtained for a prismatic shear-deformable Timoshenko beam. Exact solutions for the deflection, horizontal displacement, and rotation of cross-section are derived analytically. Two deflections of small and large scale exist under three-point bending. The solutions corresponding to linearized model coincide with the well-known solutions to the classical Timoshenko beams. Numerical calculations are carried out to show the effect of the important parameters such as shear rigidity of the beam and the coefficient of friction at the contact position between the beam and supports on the deflection. The load-deflection curves are graphically presented. A comparison of large deflections and large rotations with their classical counterparts and with experimental data is made. The obtained results are useful in safety design of linear and non-linear beams subject to three-point bending.

  7. UWB Wind Turbine Blade Deflection Sensing for Wind Energy Cost Reduction.

    PubMed

    Zhang, Shuai; Jensen, Tobias Lindstrøm; Franek, Ondrej; Eggers, Patrick C F; Olesen, Kim; Byskov, Claus; Pedersen, Gert Frølund

    2015-01-01

    A new application of utilizing ultra-wideband (UWB) technology to sense wind turbine blade deflections is introduced in this paper for wind energy cost reduction. The lower UWB band of 3.1-5.3 GHz is applied. On each blade, there will be one UWB blade deflection sensing system, which consists of two UWB antennas at the blade root and one UWB antenna at the blade tip. The detailed topology and challenges of this deflection sensing system are addressed. Due to the complexity of the problem, this paper will first realize the on-blade UWB radio link in the simplest case, where the tip antenna is situated outside (and on the surface of) a blade tip. To investigate this case, full-blade time-domain measurements are designed and conducted under different deflections. The detailed measurement setups and results are provided. If the root and tip antenna locations are properly selected, the first pulse is always of sufficient quality for accurate estimations under different deflections. The measured results reveal that the blade tip-root distance and blade deflection can be accurately estimated in the complicated and lossy wireless channels around a wind turbine blade. Some future research topics on this application are listed finally. PMID:26274964

  8. Evaluation of cuspal deflection in premolar teeth restored with low shrinkable resin composite (in vitro study)

    PubMed Central

    Labib, Labib Mohamed; Nabih, Sameh Mahmoud; Baroudi, Kusai

    2015-01-01

    Objectives: This study evaluated cuspal deflection in premolar teeth restored with low shrinkable resin composite. Materials and Methods: A total of 40 human premolars were used for cuspal deflection evaluation in this study. Each group was divided into four equal groups according to the type of resin composite and the adhesive used as follows: group A: Using low shrinkable resin composite (silorane) with its adhesive system; group B: Using low shrinkable composite (silorane) with G-bond; group C: Using Filtek Z350 composite with G-bond; and group D: Using Filtek Z350 composite with AdheSE. Cusp deflection was detected using Universal measuring microscope and laser horizontal metroscope. Results: This study was done to investigate the effect of polymerization shrinkage stresses of two resin composite materials (Filtek Z350 and Filtek P90) on cuspal deflection of mesio-occluso-distal restoration. For this study, the extracted non-carious maxillary second premolars were selected. Forty teeth that showed no more than 5% variation in their dimensions were used. A significant increase in cuspal deflection of cavities restored with the methacrylate-based (Filtek Z350) compared with the silorane (P90) resin-based composites was obtained. Conclusion: The change in the organic matrix or materials formulation of the resin composite using silorane has a positive effect on controlling the cusp deflection. PMID:26759800

  9. Using ForeCAT Deflections and Rotations to Constrain the Early Evolution of CMEs

    NASA Astrophysics Data System (ADS)

    Kay, C.; Opher, M.; Colaninno, R. C.; Vourlidas, A.

    2016-08-01

    To accurately predict the space weather effects of the impacts of coronal mass ejection (CME) at Earth one must know if and when a CME will impact Earth and the CME parameters upon impact. In 2015 Kay et al. presented Forecasting a CME’s Altered Trajectory (ForeCAT), a model for CME deflections based on the magnetic forces from the background solar magnetic field. Knowing the deflection and rotation of a CME enables prediction of Earth impacts and the orientation of the CME upon impact. We first reconstruct the positions of the 2010 April 8 and the 2012 July 12 CMEs from the observations. The first of these CMEs exhibits significant deflection and rotation (34° deflection and 58° rotation), while the second shows almost no deflection or rotation (<3° each). Using ForeCAT, we explore a range of initial parameters, such as the CME’s location and size, and find parameters that can successfully reproduce the behavior for each CME. Additionally, since the deflection depends strongly on the behavior of a CME in the low corona, we are able to constrain the expansion and propagation of these CMEs in the low corona.

  10. Experimental estimating deflection of a simple beam bridge model using grating eddy current sensors.

    PubMed

    Lü, Chunfeng; Liu, Weiwen; Zhang, Yongjie; Zhao, Hui

    2012-01-01

    A novel three-point method using a grating eddy current absolute position sensor (GECS) for bridge deflection estimation is proposed in this paper. Real spatial positions of the measuring points along the span axis are directly used as relative reference points of each other rather than using any other auxiliary static reference points for measuring devices in a conventional method. Every three adjacent measuring points are defined as a measuring unit and a straight connecting bar with a GECS fixed on the center section of it links the two endpoints. In each measuring unit, the displacement of the mid-measuring point relative to the connecting bar measured by the GECS is defined as the relative deflection. Absolute deflections of each measuring point can be calculated from the relative deflections of all the measuring units directly without any correcting approaches. Principles of the three-point method and displacement measurement of the GECS are introduced in detail. Both static and dynamic experiments have been carried out on a simple beam bridge model, which demonstrate that the three-point deflection estimation method using the GECS is effective and offers a reliable way for bridge deflection estimation, especially for long-term monitoring. PMID:23112583

  11. Deflection-Based Aircraft Structural Loads Estimation with Comparison to Flight

    NASA Technical Reports Server (NTRS)

    Lizotte, Andrew M.; Lokos, William A.

    2005-01-01

    Traditional techniques in structural load measurement entail the correlation of a known load with strain-gage output from the individual components of a structure or machine. The use of strain gages has proved successful and is considered the standard approach for load measurement. However, remotely measuring aerodynamic loads using deflection measurement systems to determine aeroelastic deformation as a substitute to strain gages may yield lower testing costs while improving aircraft performance through reduced instrumentation weight. With a reliable strain and structural deformation measurement system this technique was examined. The objective of this study was to explore the utility of a deflection-based load estimation, using the active aeroelastic wing F/A-18 aircraft. Calibration data from ground tests performed on the aircraft were used to derive left wing-root and wing-fold bending-moment and torque load equations based on strain gages, however, for this study, point deflections were used to derive deflection-based load equations. Comparisons between the strain-gage and deflection-based methods are presented. Flight data from the phase-1 active aeroelastic wing flight program were used to validate the deflection-based load estimation method. Flight validation revealed a strong bending-moment correlation and slightly weaker torque correlation. Development of current techniques, and future studies are discussed.

  12. Deflection-Based Structural Loads Estimation From the Active Aeroelastic Wing F/A-18 Aircraft

    NASA Technical Reports Server (NTRS)

    Lizotte, Andrew M.; Lokos, William A.

    2005-01-01

    Traditional techniques in structural load measurement entail the correlation of a known load with strain-gage output from the individual components of a structure or machine. The use of strain gages has proved successful and is considered the standard approach for load measurement. However, remotely measuring aerodynamic loads using deflection measurement systems to determine aeroelastic deformation as a substitute to strain gages may yield lower testing costs while improving aircraft performance through reduced instrumentation weight. This technique was examined using a reliable strain and structural deformation measurement system. The objective of this study was to explore the utility of a deflection-based load estimation, using the active aeroelastic wing F/A-18 aircraft. Calibration data from ground tests performed on the aircraft were used to derive left wing-root and wing-fold bending-moment and torque load equations based on strain gages, however, for this study, point deflections were used to derive deflection-based load equations. Comparisons between the strain-gage and deflection-based methods are presented. Flight data from the phase-1 active aeroelastic wing flight program were used to validate the deflection-based load estimation method. Flight validation revealed a strong bending-moment correlation and slightly weaker torque correlation. Development of current techniques, and future studies are discussed.

  13. Effect of acid solutions on plants studied by the optical beam deflection method.

    PubMed

    Nie, Liangjiao; Kuboda, Mitsutoshi; Inoue, Tomomi; Wu, Xingzheng

    2013-12-01

    The optical beam deflection method was applied to study the effects of acid solution on both a terrestial and aquatic plants Egeria and Cerastium, which are common aquatic plant and terrestial weed respectively. A probe beam from a He-Ne laser was passed through a vicinity of a leaf of the plants, which were put in culture dishes filled with acid solutions. Deflection signals of the probe beam were monitored and compared for acid solutions with different pH values. The results of Egria showed that the deflection signals changed dramatically when pH values of acid solutions were 2.0 and 3.0, while little at pH of 4.0 and 5.0. For Cerastium when pH were below 3.0, deflection signals changed greatly with time at the begining. After a certain period of time, deflection signals changed little with time. When pH value was above 4.0, deflection signals of Cerastium were still changing with time even after 20 hours. The results suggested that the damage threshold of pH was between 3.0 and 4.0 for both the land and aquatic plants. PMID:25078849

  14. UWB Wind Turbine Blade Deflection Sensing for Wind Energy Cost Reduction

    PubMed Central

    Zhang, Shuai; Jensen, Tobias Lindstrøm; Franek, Ondrej; Eggers, Patrick C. F.; Olesen, Kim; Byskov, Claus; Pedersen, Gert Frølund

    2015-01-01

    A new application of utilizing ultra-wideband (UWB) technology to sense wind turbine blade deflections is introduced in this paper for wind energy cost reduction. The lower UWB band of 3.1–5.3 GHz is applied. On each blade, there will be one UWB blade deflection sensing system, which consists of two UWB antennas at the blade root and one UWB antenna at the blade tip. The detailed topology and challenges of this deflection sensing system are addressed. Due to the complexity of the problem, this paper will first realize the on-blade UWB radio link in the simplest case, where the tip antenna is situated outside (and on the surface of) a blade tip. To investigate this case, full-blade time-domain measurements are designed and conducted under different deflections. The detailed measurement setups and results are provided. If the root and tip antenna locations are properly selected, the first pulse is always of sufficient quality for accurate estimations under different deflections. The measured results reveal that the blade tip-root distance and blade deflection can be accurately estimated in the complicated and lossy wireless channels around a wind turbine blade. Some future research topics on this application are listed finally. PMID:26274964

  15. The preparation and degradation performance of CdS photocatalysts to methyl orange solution.

    PubMed

    Duan, Limei; Zhao, Weiqiang; Xu, Ling; Chen, Xiaohong; Lita, A; Liu, Zongrui

    2013-03-01

    In this paper, the CdS samples were prepared using thiourea or sodium sulfide as sulfur source by hydrothermal or solvothermal synthesis method, the results of XRD, TEM and SEM showed all the samples belong to hexagonal CdS nano-material with different morphologies. Using the degradation of methyl orange solution as a model reaction, the photocatalytic performance of different CdS samples was measured, and the samples prepared using thiourea as sulfur source exhibited better photocatalytic activity than those using sodium sulfide as sulfur source. The factors on degradation effect were discussed including the pH value of degradation system and the type of light source. The degradation effect of CdS samples increased with the pH value decreased, and the degradation effect was better when the methyl orange solution was irradiated under sunlight than under 250 W mercury lamp. PMID:23755673

  16. Bonding, vibrational, and electrical characteristics of CdS nanostructures embedded in polyvinyl alcohol matrix

    SciTech Connect

    Mondal, S. P.; Dhar, A.; Ray, S. K.; Chakraborty, A. K.

    2009-04-15

    CdS nanocomposites have been grown in polyvinyl alcohol matrix by a chemical synthesis process. The transmission electron micrographs of nanocomposites synthesized at 70-90 deg. C temperature showed the growth of needlelike and junctionlike nanostructures. X-ray photoelectron spectroscopy analysis revealed the growth of stoichiometric CdS without the formation of any intermediate phases at the CdS-polyvinyl alcohol interface. Raman spectra of first order longitudinal optical phonon peak has been analyzed using phonon dispersion model to detect the surface phonon modes in CdS nanoneedles and wires. The origin of negative differential resistance behavior in current-voltage characteristics for junctionlike CdS nanocomposites has been discussed.

  17. Preparation and characterization of CdS nanoparticles decorated into titanate nanotubes and their photocatalytic properties

    NASA Astrophysics Data System (ADS)

    Xiao, Ming Wei; Shi Wang, Li; Wu, Yan Dan; Huang, Xin Jian; Dang, Zhi

    2008-01-01

    Nanoscopic CdS particles are decorated into the microchannel with nanometre-scale diameter of titanate nanotubes (TNTs) by using nonionic thioacetamide (TAA) as a sulfide precursor (labelled as CdS(TAA)/TNTs). The characterizations by XPS, TEM, XRD, Raman spectroscopy and UV-vis absorption confirm that CdS nanoparticles with smaller size and more homogeneous dispersion are obtained by using a TAA precursor in contrast to the particles predominantly formed on the surface of TNTs by adding ionic Na2S as a precursor (labelled as CdS(Na2S)/TNTs). As is expected, the photocatalytic activities of the nanosized CdS sensitized TNTs nanocrystal materials were superior to those of simple CdS and TNTs in the oxidation of rhodamine B under visible light irradiation. Furthermore, the comparison of photocatalysis activity between CdS(TAA)/TNTs and CdS(Na2S)/TNTs is also discussed.

  18. An Optimal CDS Construction Algorithm with Activity Scheduling in Ad Hoc Networks.

    PubMed

    Penumalli, Chakradhar; Palanichamy, Yogesh

    2015-01-01

    A new energy efficient optimal Connected Dominating Set (CDS) algorithm with activity scheduling for mobile ad hoc networks (MANETs) is proposed. This algorithm achieves energy efficiency by minimizing the Broadcast Storm Problem [BSP] and at the same time considering the node's remaining energy. The Connected Dominating Set is widely used as a virtual backbone or spine in mobile ad hoc networks [MANETs] or Wireless Sensor Networks [WSN]. The CDS of a graph representing a network has a significant impact on an efficient design of routing protocol in wireless networks. Here the CDS is a distributed algorithm with activity scheduling based on unit disk graph [UDG]. The node's mobility and residual energy (RE) are considered as parameters in the construction of stable optimal energy efficient CDS. The performance is evaluated at various node densities, various transmission ranges, and mobility rates. The theoretical analysis and simulation results of this algorithm are also presented which yield better results. PMID:26221627

  19. Single-Source Molecular Precursor for Synthesis of CdS Nanoparticles and Nanoflowers

    NASA Astrophysics Data System (ADS)

    Salavati-Niasari, Masoud; Sobhani, Azam

    2012-04-01

    CdS Semiconductor nanostructures were synthesized by using two different methods. Using triphenylphosphine (C18H15P) and oleylamine (C18H37N) as surfactant, CdS semiconductor nanocrystals with a size ranging from 30 to 90 nm can be synthesized by thermal decomposition of precursor [bis(thiosemicarbazide)cadmium(II)]. CdS nanoflowers were synthesized via hydrothermal decomposition of [bis(thiosemicarbazide) cadmium(II)] without any surfactant. X-ray diffraction (XRD) patterns confirm that the resulting samples were a pure hexagonal phase of CdS. The optical property test indicates that the absorption peak of the samples shifts towards short wavelength, and the blue shift phenomenon might be ascribed to the quantum effect.

  20. Mixed-solvothermal synthesis of CdS micro/nanostructures and their optical properties

    NASA Astrophysics Data System (ADS)

    Zhong, Shengliang; Zhang, Linfei; Huang, Zhenzhong; Wang, Shangping

    2011-01-01

    Several novel cadmium sulfide (CdS) micro/nanostructures, including cauliflower-like microspheres, football-like microspheres, tower-like microrods, and dendrites were controllably prepared via an oxalic acid-assisted solvothermal route using ethylene glycol (EG) and H2O as pure and mixed solvents with different S sources. The as-prepared products were characterized by X-ray powder diffraction (XRD), scanning electronic microscope (SEM) and UV-vis spectrophotometer (UV). It was found that CdS micro/nanostructures can be selectively obtained by varying the composition of solvent, concentration of oxalic acid, and sulfur sources. UV-vis absorption spectra reveal that their absorption properties are shape-dependent. The possible formation process of the CdS micro/nanostructures was briefly discussed. This route provides a facile way to tune the morphologies of CdS over a wide range.

  1. Structural and chemical properties of highly oriented cadmium sulfide (CdS) cauliflower films

    NASA Astrophysics Data System (ADS)

    Vemuri, R. S.; Gullapalli, S. K.; Zubia, D.; McClure, J. C.; Ramana, C. V.

    2010-08-01

    Cadmium sulfide (CdS) films have been produced by sputter-deposition varying the sputtering-power ( P) in the range of 60-120 W. The crystal structure, morphology and chemical quality of the CdS films has been investigated employing X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and X-ray spectrometry (EDS). Structural characterization indicates that all the CdS layers exhibit cauliflower morphology. Highly oriented, single phase hexagonal-CdS films can be produced at P = 75-105 W while the films at other power contain mixed phases. Characterization using XPS and EDS indicate that the CdS layers are nearly stoichiometric at P = 75-105 W, at which point S-deficiency is induced resulting in Cd-rich-CdS layers.

  2. Development of a Higher Fidelity Model for the Cascade Distillation Subsystem (CDS)

    NASA Technical Reports Server (NTRS)

    Perry, Bruce; Anderson, Molly

    2014-01-01

    Significant improvements have been made to the ACM model of the CDS, enabling accurate predictions of dynamic operations with fewer assumptions. The model has been utilized to predict how CDS performance would be impacted by changing operating parameters, revealing performance trade-offs and possibilities for improvement. CDS efficiency is driven by the THP coefficient of performance, which in turn is dependent on heat transfer within the system. Based on the remaining limitations of the simulation, priorities for further model development include: center dot Relaxing the assumption of total condensation center dot Incorporating dynamic simulation capability for the buildup of dissolved inert gasses in condensers center dot Examining CDS operation with more complex feeds center dot Extending heat transfer analysis to all surfaces

  3. Fluorescent CdS Quantum Dots: Synthesis, Characterization, Mechanism and Interaction with Gold Nanoparticles.

    PubMed

    Yao, Jun; Yang, Mei; Liu, Yu; Duan, Yixiang

    2015-05-01

    CdS quantum dot (QD) is a typical kind of II-IV nanoparticles, which plays an important role in the common type of core-shell QDs. It is of great practical significance to synthesize the water-soluble CdS QDs used in multicolor biomarkers and prepare core-shell QDs. In our case, we came up with a novel green method to manufacture CdS QDs with high quality, different size, and adopted UV-vis absorption, fluorescence, FTIR, XPS, HRTEM, SAED and STEM-EDX to discuss their growth mechanism. We successfully constructed fluorescence resonance energy transfer (FRET) system between CdS QDs and gold nanoparticles (AuNPs), then comprehensively and systematically studied the interaction between them. PMID:26504997

  4. Development and applications of the heterostructures synthesis based on CdS nanowires.

    PubMed

    Yan, Shancheng; Shi, Yi; Sun, Litao; Yan, Wenfu; Zhou, Minmin; Hu, Dong; Wu, Jiansheng; Wang, Jianyu; Shi, Bingjie; Lan, Xinke

    2013-01-01

    Semiconducting nanowire heterostructures are of particular interest because of their fascinating properties and potential applications in the field of nanoscale science. CdS, with a direct bandgap of 2.42 eV, is considered to be an excellent material for various optoelectronic applications in the visible range of the electromagnetic spectrum. On account of this, the diverse heterostructures based on CdS nanowires have drawn great attention owing to their novel properties. Here, we focus on recent routes used to synthesize diverse heterostructures based on CdS nanowires and the emergent properties of the one-dimensional nanowires heterostructures, and discuss their potential applicability in different fields. In particular, the mechanisms of various synthetic methods for the heterostructure based on the CdS nanowires are discussed detailedly. PMID:23646694

  5. Continuous Microreactor-Assisted Solution Deposition for Scalable Production of CdS Films

    SciTech Connect

    Ramprasad, Sudhir; Su, Yu-Wei; Chang, Chih-Hung; Paul, Brian; Palo, Daniel R.

    2013-06-13

    Solution deposition offers an attractive, low temperature option in the cost effective production of thin film solar cells. Continuous microreactor-assisted solution deposition (MASD) was used to produce nanocrystalline cadmium sulfide (CdS) films on fluorine doped tin oxide (FTO) coated glass substrates with excellent uniformity. We report a novel liquid coating technique using a ceramic rod to efficiently and uniformly apply reactive solution to large substrates (152 mm × 152 mm). This technique represents an inexpensive approach to utilize the MASD on the substrate for uniform growth of CdS films. Nano-crystalline CdS films have been produced from liquid phase at ~90°C, with average thicknesses of 70 nm to 230 nm and with a 5 to 12% thickness variation. The CdS films produced were characterized by UV-Vis spectroscopy, transmission electron microscopy, and X-Ray diffraction to demonstrate their suitability to thin-film solar technology.

  6. An Optimal CDS Construction Algorithm with Activity Scheduling in Ad Hoc Networks

    PubMed Central

    Penumalli, Chakradhar; Palanichamy, Yogesh

    2015-01-01

    A new energy efficient optimal Connected Dominating Set (CDS) algorithm with activity scheduling for mobile ad hoc networks (MANETs) is proposed. This algorithm achieves energy efficiency by minimizing the Broadcast Storm Problem [BSP] and at the same time considering the node's remaining energy. The Connected Dominating Set is widely used as a virtual backbone or spine in mobile ad hoc networks [MANETs] or Wireless Sensor Networks [WSN]. The CDS of a graph representing a network has a significant impact on an efficient design of routing protocol in wireless networks. Here the CDS is a distributed algorithm with activity scheduling based on unit disk graph [UDG]. The node's mobility and residual energy (RE) are considered as parameters in the construction of stable optimal energy efficient CDS. The performance is evaluated at various node densities, various transmission ranges, and mobility rates. The theoretical analysis and simulation results of this algorithm are also presented which yield better results. PMID:26221627

  7. Growth and characterization of CdS thin films on polymer substrates for photovoltaic applications.

    PubMed

    Park, Yongseob; Kim, Eung Kwon; Lee, Suho; Lee, Jaehyeong

    2014-05-01

    In this work, cadmium sulfide (CdS) films were deposited on flexible polymer substrates such as polycarbonate (PC) and polyethylene terephthalate (PET). The r.f. magnetron sputtering, which is cost-effective scalable technique, was used for the film deposition. The structural and optical properties of the films grown at different sputtering pressures were investigated. When the CdS film was deposited at lower pressure, the crystallinity and the preferred orientation toward c-axis in hexagonal phase was improved. However, the optical transmittance was reduced as the sputtering pressure was decreased. Compared with the glass substrate, CdS films grown on polymer substrates were exhibited some wore structural and optical characteristics. CdTe thin film solar cell applied to sputtered CdS as a window layer showed a maximum efficiency of 11.6%. PMID:24734656

  8. Nonlinear optical enhancement induced by synergistic effect of graphene nanosheets and CdS nanocrystals

    NASA Astrophysics Data System (ADS)

    Zhu, Baohua; Wang, Fangfang; Cao, Yawan; Wang, Chong; Wang, Ji; Gu, Yuzong

    2016-06-01

    CdS nanocrystals are attached on graphene nanosheets and their nonlinear optical properties are investigated by picosecond Z-scan technique at 532 nm. We found that synergistic effect between the graphene and CdS makes a major enhancement on the nonlinear optical absorption of graphene/CdS nanohybrid in comparison with cooperative effect, and the synergistic improvement is restricted by nonradiative defects in hybrid. The synergistic mechanism involving the local field theory and charge transfer evolution is proposed.

  9. Titanium nitride: A new Ohmic contact material for n-type CdS

    SciTech Connect

    Didden, Arjen; Battjes, Hemme; Dam, Bernard; Krol, Roel van de; Machunze, Raymond

    2011-08-01

    In devices based on CdS, indium is often used to make Ohmic contacts. Since indium is scarce and expensive, suitable replacement materials need to be found. In this work, we show that sputtered titanium nitride forms an Ohmic contact with n-type CdS. The CdS films, deposited with chemical bath deposition, have a hexagonal crystal structure and are polycrystalline, mostly with a (002) texture. The thickness of the films is {approx}600 nm, and the donor density is 1.9 x 10{sup 16} cm{sup -3}. The donor density increases to 1.5 x 10{sup 17} cm{sup -3} upon annealing. The contact resistivity of sputtered TiN on CdS is found to be 4.7 {+-} 0.6 {Omega} cm{sup 2}. This value is sufficiently small to avoid large resistive losses in most CdS device applications. To demonstrate the use of TiN in a CdS device, a Au/CdS/TiN Schottky diode was constructed. The diode has a potential barrier of 0.69 V and an ideality factor of 2.2.

  10. A Novel Cobalt-Sensitive Fluorescent Chemosensor Based on Ligand Capped CdS Quantum Dots.

    PubMed

    Faridbod, Farnoush; Jamali, Abbas; Ganjali, Mohammad Reza; Hosseini, Morteza; Norouzi, Parviz

    2015-05-01

    In this work, a ligand capped CdS QDs was synthesized, characterized and its fluorescence behavior was studied. The surface of the CdS QDs was modified using N-(3-methyl-2-(thiophene-2-carboxamido) phenyl) thiophene-2-carboxamide. The immobilized ligand on the surface of the CdS QDs can interact by cationic species due to the existence of donating atoms in its structures. Thus, effect of some metal cations on the fluorescent intensity of the ligand capped CdS QDs were studied. It was found that fluorescence intensity of the modified CdS QDs quenched selectively by addition of Co(II) ion in comparison with other cations tested. The ligand capped CdS QDs can be used as a fluorescent bulk chemosensor for detection of Co(II) ions. The fluorescent quenching is linear in the range of 1.0 × 10(-5) to 1.5 × 10(-4) mol L(-1) of Co(II) ions. The limit of detection was obtained 8.3 × 10(-7) mol L(-1). The nanosensor exhibits high selectivity toward Co(II) ions in comparison with common metal ions. PMID:25804832

  11. Optical and structural properties of sputtered CdS films for thin film solar cell applications

    SciTech Connect

    Kim, Donguk; Park, Young; Kim, Minha; Choi, Youngkwan; Park, Yong Seob; Lee, Jaehyoeng

    2015-09-15

    Graphical abstract: Photo current–voltage curves (a) and the quantum efficiency (QE) (b) for the solar cell with CdS film grown at 300 °C. - Highlights: • CdS thin films were grown by a RF magnetron sputtering method. • Influence of growth temperature on the properties of CdS films was investigated. • At higher T{sub g}, the crystallinity of the films improved and the grains enlarged. • CdS/CdTe solar cells with efficiencies of 9.41% were prepared at 300 °C. - Abstract: CdS thin films were prepared by radio frequency magnetron sputtering at various temperatures. The effects of growth temperature on crystallinity, surface morphology and optical properties of the films were characterized with X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Raman spectra, UV–visible spectrophotometry, and photoluminescence (PL) spectra. As the growth temperature was increased, the crystallinity of the sputtered CdS films was improved and the grains were enlarged. The characteristics of CdS/CdTe thin film solar cell appeared to be significantly influenced by the growth temperature of the CdS films. Thin film CdS/CdTe solar cells with efficiencies of 9.41% were prepared at a growth temperature of 300 °C.

  12. Map Separates

    USGS Publications Warehouse

    U.S. Geological Survey

    2001-01-01

    U.S. Geological Survey (USGS) topographic maps are printed using up to six colors (black, blue, green, red, brown, and purple). To prepare your own maps or artwork based on maps, you can order separate black-and-white film positives or negatives for any color printed on a USGS topographic map, or for one or more of the groups of related features printed in the same color on the map (such as drainage and drainage names from the blue plate.) In this document, examples are shown with appropriate ink color to illustrate the various separates. When purchased, separates are black-and-white film negatives or positives. After you receive a film separate or composite from the USGS, you can crop, enlarge or reduce, and edit to add or remove details to suit your special needs. For example, you can adapt the separates for making regional and local planning maps or for doing many kinds of studies or promotions by using the features you select and then printing them in colors of your choice.

  13. ForeCAT - A model for magnetic deflections of coronal mass ejections

    NASA Astrophysics Data System (ADS)

    Kay, Christina D.

    2016-01-01

    Frequently, the Sun explosively releases bubbles of magnetized plasma known as coronal mass ejections (CMEs), which can produce adverse space weather effects at Earth. Accurate space weather forecasting requires knowledge of the trajectory of CMEs. Decades of observations show that CMEs can deflect from a purely radial trajectory, however, no consensus exists as to the cause of these deflections. We developed a model for CME deflection and rotation from magnetic forces, called Forecasting a CME's Altered Trajectory (ForeCAT). ForeCAT has been designed to run fast enough for large parameter phase space studies, and potentially real-time predictions. ForeCAT reproduces the general trends seen in observed CME deflections. In particular, CMEs deflect toward regions of minimum magnetic energy - frequently the Heliospheric Current Sheet (HCS) on global scales. The background magnetic forces decrease rapidly with distance and quickly become negligible. Most deflections and rotations can be well-described by assuming constant angular momentum beyond 10 Rs. ForeCAT also reproduces individual observed CME deflections - the 2008 December 12, 2008 April 08, and 2010 July 12 CMEs. By determining the reduced chi-squared best fit between the ForeCAT results and the observations we constrain parameters related to the CME and the background solar wind. Additionally, we constrain whether different models for the low corona magnetic backgrounds can produce the observed CME deflection. We explore the space weather of cool M dwarfs (dMs) with surface magnetic field strengths of order kG. dMs have extreme CMEs and flares and close-in habitable zones. We use ForeCAT to explore the deflections corresponding to the range of plausible CME masses and speeds for the dM V374 Peg. The deflection of the dM CMEs exceeds their solar counterparts, and the strong magnetic gradients surrounding the dM's Astrospheric Current Sheet (ACS, analogous to the Sun's HCS) can trap the CMEs that reach it

  14. Two high-field thermodynamically stable conductivity states in photoconductive CdS, one n-type and one p-type

    SciTech Connect

    Böer, Karl W.

    2015-08-28

    Photoconductive CdS is known to be n-type and develops high-field domains in the range of negative differential conductivities. These domains have been extensively discussed, and when remaining attached to the electrodes have been renamed Böer domains (a broader definition suggested earlier is misleading) [K. Thiessen, Phys. Status Solidi B 248, 2775 (2011)]. They are occurring at high applied voltage in a range at which the current becomes highly non-ohmic that is conventionally described as N-shaped when the conductance decreases with increasing bias or as S-shaped when the current starts to increase again. In this paper only such cases will be discussed in which the current stays below significant Joule heating (no current channel formation), and only for stationary electrode-attached high-field domains. These are the cathode-attached domains that are maintained by field-quenching and are thermodynamically stable. Their finding is summarized in the first segment of this paper. When the applied voltage is increased, an anode-attached hyper-high-field domain develops that is stabilized by a hole blocking anode and will be analyzed in more detail below. It will be shown that they are a thermodynamically stable p-type photoconductive state of CdS. These two new states can be used to determine the carrier densities and mobilities as function of the field and the effective work function in dependence of the spectral distribution of the optical excitation. In a thin slab adjacent to a blocking cathode, the quasi-Fermi levels are spread to a precise amount and are kept there in the entire high-field region. This opens the opportunity to analyze with small modulation of the excitation the trap transition coefficients near these quasi-Fermi levels separately, without broadening interference from other signals. This has already resulted in the discovery of an unusually sharp electron quenching level when the CdS was in a p-type state with an anode adjacent domain. It is

  15. Performance improvement of P3HT/TiO{sub 2} coaxial heterojunction polymer solar cells by introducing a CdS interface modifier

    SciTech Connect

    Li, Yan; Wang, Cheng-Wei; Zhao, Yun; Wang, Jian; Zhou, Feng

    2012-12-15

    Coaxial heterojunction polymer solar cells consisting of vertical aligned crystalline TiO{sub 2} nanotube arrays transferred onto FTO-coated glass and ordered interpenetrating poly(3-hexylthiophene-2,5-diyl) (P3HT) have been fabricated through interface sensitization of CdS quantum dots on TiO{sub 2} nanotube walls. The performances of structurally identical polymer solar cells with and without CdS quantum dots sensitization were investigated and compared. The sensitized P3HT/CdS-TiO{sub 2} cell demonstrated an open-circuit photovoltage of 0.72 V and a short-circuit current of 8.29 mA/cm{sup 2} while the P3HT/TiO{sub 2} cell was 0.41 V and 5.64 mA/cm{sup 2}. The efficiency of this sensitized cell represents a more than four-fold improvement compared to the non-sensitized cell. By probing the charge transport characteristics at interfaces and the mechanism of photoelectric conversion, it is found the moderately interfacial CdS QDs plays the role of assisting charge separation and suppression of back recombination at interfaces, which accounts for the observed enhanced J{sub sc} and V{sub oc} in photovoltaic performance. - Graphical abstract: Schematic illustration of the Au/P3HT/CdS-TiO{sub 2}/FTO coaxial heterojunction polymer solar cell and its photovoltaic property compared with Au/P3HT/TiO{sub 2}/FTO cell. Highlights: Black-Right-Pointing-Pointer CdS QDs sensitized P3HT/TiO{sub 2} solid coaxial heterojunction solar cells are fabricated. Black-Right-Pointing-Pointer The V{sub oc} of such sensitized polymer solar cell reaches the value as high as 0.72 V. Black-Right-Pointing-Pointer 4.5 times higher PCE obtains as compared with the non-sensitized cell. Black-Right-Pointing-Pointer The dominate roles of CdS QDs sensitization on the PCE enhancement are investigated.

  16. Two high-field thermodynamically stable conductivity states in photoconductive CdS, one n-type and one p-type

    NASA Astrophysics Data System (ADS)

    Böer, Karl W.

    2015-08-01

    Photoconductive CdS is known to be n-type and develops high-field domains in the range of negative differential conductivities. These domains have been extensively discussed, and when remaining attached to the electrodes have been renamed Böer domains (a broader definition suggested earlier is misleading) [K. Thiessen, Phys. Status Solidi B 248, 2775 (2011)]. They are occurring at high applied voltage in a range at which the current becomes highly non-ohmic that is conventionally described as N-shaped when the conductance decreases with increasing bias or as S-shaped when the current starts to increase again. In this paper only such cases will be discussed in which the current stays below significant Joule heating (no current channel formation), and only for stationary electrode-attached high-field domains. These are the cathode-attached domains that are maintained by field-quenching and are thermodynamically stable. Their finding is summarized in the first segment of this paper. When the applied voltage is increased, an anode-attached hyper-high-field domain develops that is stabilized by a hole blocking anode and will be analyzed in more detail below. It will be shown that they are a thermodynamically stable p-type photoconductive state of CdS. These two new states can be used to determine the carrier densities and mobilities as function of the field and the effective work function in dependence of the spectral distribution of the optical excitation. In a thin slab adjacent to a blocking cathode, the quasi-Fermi levels are spread to a precise amount and are kept there in the entire high-field region. This opens the opportunity to analyze with small modulation of the excitation the trap transition coefficients near these quasi-Fermi levels separately, without broadening interference from other signals. This has already resulted in the discovery of an unusually sharp electron quenching level when the CdS was in a p-type state with an anode adjacent domain. It is

  17. ISOTOPE SEPARATORS

    DOEpatents

    Bacon, C.G.

    1958-08-26

    An improvement is presented in the structure of an isotope separation apparatus and, in particular, is concerned with a magnetically operated shutter associated with a window which is provided for the purpose of enabling the operator to view the processes going on within the interior of the apparatus. The shutier is mounted to close under the force of gravity in the absence of any other force. By closing an electrical circuit to a coil mouated on the shutter the magnetic field of the isotope separating apparatus coacts with the magnetic field of the coil to force the shutter to the open position.

  18. Ferroelectric gated electrical transport in CdS nanotetrapods.

    PubMed

    Fu, Wangyang; Qin, Shengyong; Liu, Lei; Kim, Tae-Hwan; Hellstrom, Sondra; Wang, Wenlong; Liang, Wenjie; Bai, Xuedong; Li, An-Ping; Wang, Enge

    2011-05-11

    Complex nanostructures such as branched semiconductor nanotetrapods are promising building blocks for next-generation nanoelectronics. Here we report on the electrical transport properties of individual CdS tetrapods in a field effect transistor (FET) configuration with a ferroelectric Ba(0.7)Sr(0.3)TiO(3) film as high-k, switchable gate dielectric. A cryogenic four-probe scanning tunneling microscopy (STM) is used to probe the electrical transport through individual nanotetrapods at different temperatures. A p-type field effect is observed at room temperature, owing to the enhanced gate capacitance coupling. And the reversible remnant polarization of the ferroelectric gate dielectric leads to a well-defined nonvolatile memory effect. The field effect is shown to originate from the channel tuning in the arm/core/arm junctions of nanotetrapods. At low temperature (8.5 K), the nanotetrapod devices exhibit a ferroelectric-modulated single-electron transistor (SET) behavior. The results illustrate how the characteristics of a ferroelectric such as switchable polarization and high dielectric constant can be exploited to control the functionality of individual three-dimensional nanoarchitectures. PMID:21513340

  19. A new 9T global shutter pixel with CDS technique

    NASA Astrophysics Data System (ADS)

    Liu, Yang; Ma, Cheng; Zhou, Quan; Wang, Xinyang

    2015-04-01

    Benefiting from motion blur free, Global shutter pixel is very widely used in the design of CMOS image sensors for high speed applications such as motion vision, scientifically inspection, etc. In global shutter sensors, all pixel signal information needs to be stored in the pixel first and then waiting for readout. For higher frame rate, we need very fast operation of the pixel array. There are basically two ways for the in pixel signal storage, one is in charge domain, such as the one shown in [1], this needs complicated process during the pixel fabrication. The other one is in voltage domain, one example is the one in [2], this pixel is based on the 4T PPD technology and normally the driving of the high capacitive transfer gate limits the speed of the array operation. In this paper we report a new 9T global shutter pixel based on 3-T partially pinned photodiode (PPPD) technology. It incorporates three in-pixel storage capacitors allowing for correlated double sampling (CDS) and pipeline operation of the array (pixel exposure during the readout of the array). Only two control pulses are needed for all the pixels at the end of exposure which allows high speed exposure control.

  20. DIE Deflection Modeling: Empirical Validation and Tech Transfer

    SciTech Connect

    R. Allen Miller

    2003-05-28

    This report summarizes computer modeling work that was designed to help understand how the die casting die and machine contribute to parting plane separation during operation. Techniques developed in earlier research (8) were applied to complete a large computational experiment that systematically explored the relationship between the stiffness of the machine platens and key dimensional and structural variables (platen area covered, die thickness, platen thickness, thickness of insert and the location of the die with respect to the platen) describing the die/machine system. The results consistently show that there are many significant interactions among the variables and it is the interactions, more than the individual variables themselves, which determine the performance of the machine/die system. That said, the results consistently show that it is the stiffness of the machine platens that has the largest single impact on die separation.

  1. Design of Spacecraft Missions to Test Kinetic Impact for Asteroid Deflection

    NASA Technical Reports Server (NTRS)

    Hernandez, Sonia; Barbee, Brent W.

    2011-01-01

    There are currently over 8,000 known near-Earth asteroids (NEAs), and more are being discovered on a continual basis. More than 1,200 of these are classified as Potentially Hazardous Asteroids (PHAs) because their Minimum Orbit Intersection Distance (MOID) with Earth's orbit is <= 0.05 AU and their estimated diameters are >= 150 m. To date, 178 Earth impact structures have been discovered, indicating that our planet has previously been struck with devastating force by NEAs and will be struck again. Such collisions are aperiodic events and can occur at any time. A variety of techniques have been proposed to defend our planet from NEA impacts by deflecting the incoming asteroid. However, none of these techniques have been tested. Unless rigorous testing is conducted to produce reliable asteroid deflection systems, we will be forced to deploy completely untested -- and therefore unreliable -- deflection missions when a sizable asteroid on a collision course with Earth is discovered. Such missions will have a high probability of failure. We propose to address this problem with a campaign of deflection technology test missions deployed to harmless NEAs. The objective of these missions is to safely evaluate and refine the mission concepts and asteroid deflection system designs. Our current research focuses on the kinetic impactor, one of the simplest proposed asteroid deflection techniques in which a spacecraft is sent to collide with an asteroid at high relative velocity. By deploying test missions in the near future, we can characterize the performance of this deflection technique and resolve any problems inherent to its execution before needing to rely upon it during a true emergency. In this paper we present the methodology and results of our survey, including lists of NEAs for which safe and effective kinetic impactor test missions may be conducted within the next decade. Full mission designs are also presented for the NEAs which offer the best mission opportunities.

  2. Effect of the finite size of an asteroid on its deflection using a tether-ballast system

    NASA Astrophysics Data System (ADS)

    Mashayekhi, Mohammad J.; Misra, Arun K.

    2016-04-01

    Potentially hazardous near-Earth objects which can impose a significant threat on life on the planet have generated a lot of interest in the study of various asteroid deflection strategies. There are numerous asteroid deflection techniques suggested and discussed in the literature. This paper is focused on one of the non-destructive asteroid deflection strategies by attaching a long tether-ballast system to the asteroid. In the existing literature on this technique, very simplified models of the asteroid-tether-ballast system including a point mass model of the asteroid have been used. In this paper, the dynamical effect of using a finite size asteroid model on the asteroid deflection achieved is analyzed in detail. It has been shown that considering the finite size of the asteroid, instead of the point mass approximation, can have significant influence on the deflection predicted. Furthermore the effect of the tether-deployment stage, which is an essential part of any realistic asteroid deflection mission, on the predicted deflection is studied in this paper. Finally the effect of cutting the tether on the deflection achieved is analyzed and it has been shown that depending on the orbital properties of the asteroid as well as its size and rotational rate, cutting the tether at an appropriate time can increase the deflection achieved. Several numerical examples have been used in this paper to elaborate on the proposed technique and to quantitatively analyze the effect of different parameters on the asteroid deflection.

  3. Effect of the finite size of an asteroid on its deflection using a tether-ballast system

    NASA Astrophysics Data System (ADS)

    Mashayekhi, Mohammad J.; Misra, Arun K.

    2016-07-01

    Potentially hazardous near-Earth objects which can impose a significant threat on life on the planet have generated a lot of interest in the study of various asteroid deflection strategies. There are numerous asteroid deflection techniques suggested and discussed in the literature. This paper is focused on one of the non-destructive asteroid deflection strategies by attaching a long tether-ballast system to the asteroid. In the existing literature on this technique, very simplified models of the asteroid-tether-ballast system including a point mass model of the asteroid have been used. In this paper, the dynamical effect of using a finite size asteroid model on the asteroid deflection achieved is analyzed in detail. It has been shown that considering the finite size of the asteroid, instead of the point mass approximation, can have significant influence on the deflection predicted. Furthermore the effect of the tether-deployment stage, which is an essential part of any realistic asteroid deflection mission, on the predicted deflection is studied in this paper. Finally the effect of cutting the tether on the deflection achieved is analyzed and it has been shown that depending on the orbital properties of the asteroid as well as its size and rotational rate, cutting the tether at an appropriate time can increase the deflection achieved. Several numerical examples have been used in this paper to elaborate on the proposed technique and to quantitatively analyze the effect of different parameters on the asteroid deflection.

  4. Assessment of Hot-Carrier Effects on Charge Separation in Type-II CdS/CdTe Heterostructured Nanorods.

    PubMed

    Okano, Makoto; Sakamoto, Masanori; Teranishi, Toshiharu; Kanemitsu, Yoshihiko

    2014-09-01

    Charge separation in semiconducting materials is an essential process that determines the efficiency of photovoltaic devices and photocatalysts. Herein, we report the charge-separation dynamics in type-II CdS/CdTe heterostructured nanorods revealed by femtosecond transient-absorption (TA) measurements with a broad-band white-light probe. Under selective excitation of the CdTe segment, bleaching signals at the band gap energy of CdS were clearly observed with a rise component on a subpicosecond time scale, which indicates efficient electron transfer from CdTe to CdS. The pump-energy dependence of the TA dynamics shows that hot electrons rapidly relax to the bottom of the conduction band of CdTe, and then the electrons transfer to the CdS segment. PMID:26278242

  5. SEPARATION PROCESS

    DOEpatents

    Stoughton, R.W.

    1961-10-24

    A process for separating tetravalent plutonium from aqueous solutions and from niobium and zirconium by precipitation on lanthanum oxalate is described. The oxalate ions of the precipitate may be decomposed by heating in the presence of an oxidizing agent, forming a plutonium compound readily soluble in acid. (AEC)

  6. Separation Group.

    ERIC Educational Resources Information Center

    Addington, Jean

    1992-01-01

    Describes eight-week short-term group designed to help separated or divorced men and women move through related adjustment phase in focused group setting. Discusses constructs that form the foundations of this short-term psychoeducational and support group and presents brief overview of psychological difficulties that occur as result of marital…

  7. Vacuum arc plasma mass separator

    NASA Astrophysics Data System (ADS)

    Paperny, V. L.; Krasov, V. I.; Lebedev, N. V.; Astrakchantsev, N. V.; Chernikch, A. A.

    2015-02-01

    The propagation of a metal plasma flow in a transport system with a curvilinear magnetic field was studied experimentally. The flow was generated by a pulsed vacuum arc discharge with a composite (W+Fe) cathode. The ion energy measurements at the transport system output showed that all ion components were accelerated up to equal energies per charge unit, about 150 eV and 320 eV in the outer and inner areas of the curved plasma flow, respectively. The spatial separation of the atoms of the cathode material was measured at the system output by x-ray fluorescence spectrometry. The ions of the lighter element (Fe) were concentrated in the inner part of the cathodic plasma flow deflected by the magnetic field while the distribution of the heavy element (W) was substantially shifted toward the outer area of the flow. The maximum mass separation efficiency reached 45, the effective value being 7.7. Such a system is promising for use in plasma technology for reprocessing spent nuclear fuel, namely for the separation of the heavy radioactive fission product from nuclear waste.

  8. Separation of vinca alkaloid enantiomers by capillary electrophoresis applying cyclodextrin derivatives and characterization of cyclodextrin complexes by nuclear magnetic resonance spectroscopy.

    PubMed

    Sohajda, Tamás; Varga, Erzsébet; Iványi, Róbert; Fejos, Ida; Szente, Lajos; Noszál, Béla; Béni, Szabolcs

    2010-12-15

    In this work, the enantiomeric separation of three vinca alkaloid enantiomers (vincamine, vinpocetine and vincadifformine) has been investigated in an aqueous capillary electrophoresis (CE) system using cyclodextrins (CDs). The investigated CDs were the native alpha-, beta-, and gamma-CDs and their hydroxypropylated, randomly methylated, carboxymethylated and sulfobutylated derivatives. The first part of this study consisted of the determination of the apparent averaged complex stability constants with the selected CDs. Several parameters, such as the nature and the concentration of the CD, were studied and were found to have a significant effect on the enantiomeric resolution for all studied compounds. All three vinca alkaloids were successfully enantioseparated with CDs where different migration orders were observed in case of several CDs depending on the cavity size or substituent of the host. Chiral separation and determination of the stability constants were also performed with NMR spectroscopy which confirmed the CE results. Averaged stoichiometries of the complexes were determined using the Job plot method resulting in a 1:1 complex irrespective of the alkaloid enantiomers or cyclodextrin derivative. The structures of the inclusion complexes were elucidated using 2D ROESY NMR spectroscopy. On the basis of NMR results reversal of enantiomer migration order was clarified in various cases. PMID:20724093

  9. Synthesis and characterization of CdS nanocrystals in Maleic anhydride-Octene-1-Vinylbutyl Ether terpolymer matrix

    NASA Astrophysics Data System (ADS)

    Akperov, Oktay H.; Muradov, Mustafa B.; Malikov, Elvin Y.; Akperov, Elchin O.; Mammadova, Rasmiyya E.; Eyvazova, Goncha M.; Kukovecz, Ákos; Kónya, Zoltán

    2016-07-01

    A Maleic anhydride-Octene-1-Vinylbutyl Ether terpolymer was synthesized via the radical terpolymerization method in order to prepare a new matrix for CdS nanocrystal synthesis. CdS nanocrystals were synthesized through the reaction of thiourea with cadmium chloride. The synthesized terpolymer/CdS nanocrystal composites were characterized by several methods. Energy Dispersive X-ray analysis, Raman spectroscopy and powder X-ray diffraction methods. The room temperature UV-visible absorption spectra show a shift of the absorption edge towards higher energies. The band gap of the CdS nanocomposite is bigger than that of bulk CdS. Raman spectrum exhibits characteristic peaks of CdS. Images of the nanocomposite obtained with Atomic Force Microscopy and Transmission Electron Microscopy are the evidences of CdS nanocrystal formation in the terpolymer. Thermal investigation shows that the nanocomposite is more thermostable than the terpolymer which could be useful for application in thermo aggressive medium.

  10. Synthesis and characterization of monodispersed CdS nanoparticles in SiO 2 fibers by sol-gel method

    NASA Astrophysics Data System (ADS)

    Hullavarad, Nilima V.; Hullavarad, Shiva S.

    2007-11-01

    Cadmium sulfide (CdS) has been synthesized by a sol-gel route in order to obtain chemically protected, stable nanoparticles. The CdS nanoparticles in the SiO 2 gel matrix were dried to form monoliths of 1 in. diameter. The TEOS:H 2O:HCl:C 2H 5OH and TEOS/Cd mole ratios were varied to obtain narrow size distributed CdS nanoparticles. The UV absorption measurements indicated sharp absorption at 260 and 350 nm for different precursor compositions. SiO 2 gel containing the CdS nanoparticles was spin coated onto substrates in order to monitor the surface morphology of the samples. Scanning electron microscope measurements revealed formation of CdS nanoparticles within the branches of gel-network. Depending upon the mole ratio of additives and drying method, fibers or monolithic tablets of CdS nanoparticles could be produced.

  11. One-pot solvothermal route to self-assembly of cauliflower-shaped CdS microspheres

    NASA Astrophysics Data System (ADS)

    Ge, Ming; Cui, Yao; Liu, Lu; Zhou, Zhen

    2011-05-01

    Nearly monodispersed cauliflower-shaped CdS microspheres were prepared through a simple one-step solvothermal route on a large scale by employing sodium dodecyl sulfate (SDS) as the surfactant. Images by field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM) indicate that cauliflower-shaped CdS microspheres with diameters in the range from 1.3 to 4.5 μm are assembled by nanoparticles with an average diameter of approximately 30 nm. The possible formation mechanism of the cauliflower-shaped CdS microspheres was also proposed. The photovoltaic activity of cauliflower-shaped CdS architectures has been investigated, indicating that the as-obtained CdS microspheres exhibited higher photovoltaic performance in comparison with CdS nanoparticles.

  12. Improved stoichiometry and photoanode efficiency of thermally evaporated CdS film with quantum dots as precursor.

    PubMed

    Fan, Libo; Wang, Peng; Guo, Qiuquan; Lei, Yan; Li, Ming; Han, Hongpei; Zhao, Haifeng; Yang, Dongluo; Zheng, Zhi; Yang, Jun

    2015-08-21

    Good stoichiometry of cadmium sulfide (CdS) film facilitates its application in photovoltaic devices; however, traditional thermal evaporation usually results in a Cd-deficient CdS film at a low-substrate temperature. In this study, Cd-rich CdS quantum dots (QDs) were synthesized by a facile co-precipitation method and used as the precursor to thermally evaporate CdS film on indium tin oxide-coated glass (ITO/glass). As a consequence, the stoichiometry of CdS film was greatly improved with atomic ratio of Cd to S restored to unity. More importantly, the newly developed CdS film, with its rod-like surface microstructure, acted as an efficient photoanode in a photoelectrochemical (PEC) cell. Its properties, including surface morphology and roughness, crystal structure, chemical composition, film thickness, energy-level structure and photosensitivity, are studied in detail. PMID:26221785

  13. Improved stoichiometry and photoanode efficiency of thermally evaporated CdS film with quantum dots as precursor

    NASA Astrophysics Data System (ADS)

    Fan, Libo; Wang, Peng; Guo, Qiuquan; Lei, Yan; Li, Ming; Han, Hongpei; Zhao, Haifeng; Yang, Dongluo; Zheng, Zhi; Yang, Jun

    2015-08-01

    Good stoichiometry of cadmium sulfide (CdS) film facilitates its application in photovoltaic devices; however, traditional thermal evaporation usually results in a Cd-deficient CdS film at a low-substrate temperature. In this study, Cd-rich CdS quantum dots (QDs) were synthesized by a facile co-precipitation method and used as the precursor to thermally evaporate CdS film on indium tin oxide-coated glass (ITO/glass). As a consequence, the stoichiometry of CdS film was greatly improved with atomic ratio of Cd to S restored to unity. More importantly, the newly developed CdS film, with its rod-like surface microstructure, acted as an efficient photoanode in a photoelectrochemical (PEC) cell. Its properties, including surface morphology and roughness, crystal structure, chemical composition, film thickness, energy-level structure and photosensitivity, are studied in detail.

  14. Science case for the Asteroid Impact Mission (AIM): A component of the Asteroid Impact & Deflection Assessment (AIDA) mission

    NASA Astrophysics Data System (ADS)

    Michel, Patrick; Cheng, A.; Küppers, M.; Pravec, P.; Blum, J.; Delbo, M.; Green, S. F.; Rosenblatt, P.; Tsiganis, K.; Vincent, J. B.; Biele, J.; Ciarletti, V.; Hérique, A.; Ulamec, S.; Carnelli, I.; Galvez, A.; Benner, L.; Naidu, S. P.; Barnouin, O. S.; Richardson, D. C.; Rivkin, A.; Scheirich, P.; Moskovitz, N.; Thirouin, A.; Schwartz, S. R.; Campo Bagatin, A.; Yu, Y.

    2016-06-01

    The Asteroid Impact & Deflection Assessment (AIDA) mission is a joint cooperation between European and US space agencies that consists of two separate and independent spacecraft that will be launched to a binary asteroid system, the near-Earth asteroid Didymos, to test the kinetic impactor technique to deflect an asteroid. The European Asteroid Impact Mission (AIM) is set to rendezvous with the asteroid system to fully characterize the smaller of the two binary components a few months prior to the impact by the US Double Asteroid Redirection Test (DART) spacecraft. AIM is a unique mission as it will be the first time that a spacecraft will investigate the surface, subsurface, and internal properties of a small binary near-Earth asteroid. In addition it will perform various important technology demonstrations that can serve other space missions. The knowledge obtained by this mission will have great implications for our understanding of the history of the Solar System. Having direct information on the surface and internal properties of small asteroids will allow us to understand how the various processes they undergo work and transform these small bodies as well as, for this particular case, how a binary system forms. Making these measurements from up close and comparing them with ground-based data from telescopes will also allow us to calibrate remote observations and improve our data interpretation of other systems. With DART, thanks to the characterization of the target by AIM, the mission will be the first fully documented impact experiment at asteroid scale, which will include the characterization of the target's properties and the outcome of the impact. AIDA will thus offer a great opportunity to test and refine our understanding and models at the actual scale of an asteroid, and to check whether the current extrapolations of material strength from laboratory-scale targets to the scale of AIDA's target are valid. Moreover, it will offer a first check of the

  15. Colon Cancer Cell Separation by Dielectrophoresis

    NASA Astrophysics Data System (ADS)

    Yang, Fang; Yang, Xiaoming; Jiang, H.; Wood, P.; Hrushesky, W.; Wang, Guiren

    2009-11-01

    Separation of cancer cells from the other biological cells can be useful for clinical cancer diagnosis and cancer treatment. In this presentation, conventional dielectrophoresis (c-DEP) is used in a microfluidic chip to manipulate and collect colorectal cancer HCT116 cell, which is doped with Human Embryonic Kidney 293 cells (HEK 293). It is noticed that, the HCT116 cell are deflected to a side channel from a main channel clearly by apply electric field at particular AC frequency band. This motion caused by negative DEP can be used to separate the cancer cell from others. In this manuscript, chip design, flow condition, the DEP spectrum of the cancer cell are reported respectively, and the separation and collection efficiency are investigated as well. The sorter is microfabricated using plastic laminate technology. -/abstract- This work has been financially supported by the NSF RII funding (EP

  16. Axial flow effects on robustness of vortical structures about actively deflected wings in flapping flight

    NASA Astrophysics Data System (ADS)

    Medina, Albert; Kweon, Jihoon; Choi, Haecheon; Eldredge, Jeff D.

    2012-11-01

    Flapping wing flight has garnered much attention in the past decade driven by our desire to understand capabilities observed in nature and to develop agile small-scale aerial vehicles. Nature has demonstrated the breadth of maneuverability achievable by flapping wing flight. However, despite recent advances the role of wing flexibility remains poorly understood. In an effort to develop a deeper understanding of wing deflection effects and to explore novel approaches to increasing leading-edge vortex robustness, this three-dimensional computational study explores the aerodynamics of low aspect ratio plates, in hovering kinematics, with isolated flexion lines undergoing prescribed deflection. Major flexion lines, recognized as the primary avenue for deflection in biological fliers, are isolated here in two distinct configurations, resulting in deflection about the wing root and the wing tip, respectively. Of interest is the interaction between axial flow along the span and the vortical structures about the wing. It is proposed that the modes of deflection explored may provide a means of axial flow control for favorably promoting LEV robustness over a broad range of flapping conditions, and provide insight into the nature of flexibility in flapping wing flight. National Science Foundation, National Research Foundation of Korea.

  17. Modeling and simulations of new electrostatically driven, bimorph actuator for high beam steering micromirror deflection angles

    NASA Astrophysics Data System (ADS)

    Walton, John P.; Coutu, Ronald A.; Starman, LaVern

    2015-02-01

    There are numerous applications for micromirror arrays seen in our everyday lives. From flat screen televisions and computer monitors, found in nearly every home and office, to advanced military weapon systems and space vehicles, each application bringing with it a unique set of requirements. The microelectromechanical systems (MEMS) industry has researched many ways micromirror actuation can be accomplished and the different constraints on performance each design brings with it. This paper investigates a new "zipper" approach to electrostatically driven micromirrors with the intent of improving duel plane beam steering by coupling large deflection angles, over 30°, and a fast switching speed. To accomplish this, an extreme initial deflection is needed which can be reached using high stress bimorph beams. Currently this requires long beams and high voltage for the electrostatic pull in or slower electrothermal switching. The idea for this "zipper" approach is to stack multiple beams of a much shorter length and allow for the deflection of each beam to be added together in order to reach the required initial deflection height. This design requires much less pull-in voltage because the pull-in of one short beam will in turn reduce the height of the all subsequent beams, making it much easier to actuate. Using modeling and simulation software to characterize operations characteristics, different bimorph cantilever beam configurations are explored in order to optimize the design. These simulations show that this new "zipper" approach increases initial deflection as additional beams are added to the assembly without increasing the actuation voltage.

  18. Aerodynamic performance of a wing with a deflected tip-mounted reverse half-delta wing

    NASA Astrophysics Data System (ADS)

    Lee, T.; Su, Y. Y.

    2012-11-01

    The impact of a tip-mounted 65°-sweep reverse half-delta wing (RHDW), set at different deflections, on the aerodynamic performance of a rectangular NACA 0012 wing was investigated experimentally at Re = 2.45 × 105. This study is a continuation of the work of Lee and Su (Exp Fluids 52(6):1593-1609, 2012) on the passive control of wing tip vortex by the use of a reverse half-delta wing. The present results show that for RHDW deflection with -5° ≤ δ ≤ +15°, the lift was found to increase nonlinearly with increasing δ compared to the baseline wing. The lift increment was accompanied by an increased total drag. For negative RHDW deflection with δ < -5°, the RHDW-induced lift decrement was, however, accompanied by an improved drag. The deflected RHDW also significantly modified and weakened the tip vortex, leading to a persistently lowered lift-induced drag, regardless of its deflection, compared to the baseline wing. Physical mechanisms responsible for the observed RHDW-induced phenomenon were also discussed.

  19. An analysis of the current deflection around Dongsha Islands in the northern South China Sea

    NASA Astrophysics Data System (ADS)

    Wang, Dongxiao; Wang, Qiang; Zhou, Weidong; Cai, Shuqun; Li, Li; Hong, Bo

    2013-01-01

    Based on the in situ data and ADCP observation in fall, it is found that a northeastward current at inter-middle level flows on the Northern South China Sea (NSCS) continental shelf. This current flows almost along the isobaths, and it deflects from the isobaths veering toward deep water when flowing over the Dongsha Islands. Geographic currents derived from the climatologic hydrography data (WOA01) and absolute dynamic topography (ADT) data confirm the deflection of the northeastward current on NSCS continent. A fine resolution regional ocean model which can well reproduce the large scale circulation in the NSCS is used to analyze the dynamic about the deflection. The vorticity term balances shows that JEBAR (Joint Effect of Baroclinicity and Relief) drives the water column to depart from the isobaths. To the east of the Dongsha Islands, the isopycnal is almost orthogonal to the isobaths. The joint effect of the topographic and the baroclinic effect supplies negative vorticity and drives the water column to deflect from the isobaths and veer to deeper water. Momentum analysis along the stream line shows that, when the sea water flows around the Dongsha islands, the pressure gradient along the isobath pushes the sea water to accelerate, and then the Coriolis force orthogonal to the isobath increases and overcomes the corresponding pressure gradient, which drives the water deflected from the isobath toward the deep sea.

  20. A new approach to control a deflection of an electroplated microstructure: dual current electroplating methods

    NASA Astrophysics Data System (ADS)

    Yang, Hyun-Ho; Seo, Min-Ho; Han, Chang-Hoon; Yoon, Jun-Bo

    2013-05-01

    We propose and demonstrate a simple and novel method to control the deflection in a suspended microstructure by using a dual current electroplating (DuCE) method. The key concept of this method is to divide the structure into two layers—a bottom layer and a top layer—and then apply respective current densities in electroplating to those two layers while all other conditions are kept the same. In addition to a flat structure, the direction of structure bending is freely controlled by virtue of the DuCE method. Cantilever Ni beams with a length of 400 µm, which were electroplated by the conventional single current electroplating method, bent downward with a deflection of 3.4 µm. On the contrary, by the DuCE method, cantilever beams with a length of 400 µm showed an almost flat structure as desired. (The current densities of the bottom layer, the top layer, and the ratio of the two current densities, are 0.15, 1.24 A dm-2, and 8.3, respectively.) Consequently, a nickel electroplated spiral structure with a length of 8600 µm was suspended flat with an end deflection of less than 0.7 µm (the ratio between the deflection and length is 0.007%). This work therefore represents the unprecedented ultra-long suspended microstructure with submicrometer deflection.

  1. Applicability of moiré deflection tomography for diagnosing arc plasmas.

    PubMed

    Chen, Yun-yun; Song, Yang; He, An-zhi; Li, Zhen-hua

    2009-01-20

    The argon arc plasma whose central temperature, 1.90x10(4) K, is used as a practical example for an experiment to research the applicability of moiré deflection tomography in arc plasma flow-field diagnosis. The experimental result indicates that moiré deflection of the measured argon arc plasma is very small, even smaller than that of a common flame with the maximal temperature of nearly 1.80x10(3) K. The refractive-index gradient in moiré deflection tomography mainly contributes to the temperature gradient in essence when the probe wavelength and pressure are certain in plasma diagnosis. The applicable temperature ranges of moiré deflection tomography in the argon arc plasma diagnosis are given with the probe wavelength 532 nm at 1 atm in certain measuring error requirements. In a word, the applicable temperature range of moiré deflection tomography for arc plasma diagnosis is intimately related to the probe wavelength and the practical measuring requirements. PMID:19151817

  2. Flight measurements of buffet characteristics of the F-104 airplane for selected wing-flap deflections

    NASA Technical Reports Server (NTRS)

    Friend, E. L.; Sefic, W. J.

    1972-01-01

    A flight program was conducted on the F-104 airplane to investigate the effects of moderate deflections of wing leading- and trailing-edge flaps on the buffet characteristics at subsonic and transonic Mach numbers. Selected deflections of the wing leading and trailing-edge flaps, individually and in combination, were used to assess buffet onset, intensity, and frequency; lift curves; and wing-rock characteristics for each configuration. Increased deflection of the trailing-edge flap delayed the buffet onset and buffet intensity rise to a significantly higher airplane normal-force coefficient. Deflection of the leading-edge flap produced some delay in buffet onset and the resulting intensity rise at low subsonic speeds. Increased deflection of the trailing-edge flap provided appreciable lift increments in the angle-of-attack range covered, whereas the leading-edge flap provided lift increments only at high angles-of-attack. The pilots appreciated the increased maneuvering envelope provided by the flaps because of the improved turn capability.

  3. Effect of electrical spot welding on load deflection rate of orthodontic wires

    PubMed Central

    Alavi, Shiva; Abrishami, Arezoo

    2015-01-01

    Background: One of the methods used for joining metals together is welding, which can be carried out using different techniques such as electric spot welding. This study evaluated the effect of electric spot welding on the load deflection rate of stainless steel and chromium-cobalt orthodontic wires. Materials and Methods: In this experimental-laboratory study, load deflection rate of 0.016 × 0.022 inch stainless steel and chromium cobalt wires were evaluated in five groups (n =18): group one: Stainless steel wires, group two: chromium-cobalt wires, group three: stainless steel wires welded to stainless steel wires, group four: Stainless steel wires welded to chromium-cobalt wires, group five: chromium-cobalt wire welded to chromium-cobalt wires. Afterward, the forces induced by the samples in 0.5 mm, 1 mm, 1.5 mm deflection were measured using a universal testing machine. Then mean force measured for each group was compared with other groups. The data were analyzed using repeated measure analysis of variance (ANOVA), one-way ANOVA, and paired t-test by the SPSS software. The significance level was set as 0.05. Results: The Tukey test showed that there were significant differences between the load deflection rates of welded groups compared to control ones (P < 0.001). Conclusion: Considering the limitation of this study, the electric spot welding process performed on stainless steel and chromium-cobalt wires increased their load deflection rates. PMID:26604957

  4. Deflection test evaluation of different lots of the same nickel-titanium wire commercial brand

    PubMed Central

    Neves, Murilo Gaby; Lima, Fabrício Viana Pereira; Gurgel, Júlio de Araújo; Pinzan-Vercelino, Célia Regina Maio; Rezende, Fernanda Soares; Brandão, Gustavo Antônio Martins

    2016-01-01

    Introduction: The aim of this in vitro study was to compare the elastic properties of the load-deflection ratio of orthodontic wires of different lot numbers and the same commercial brand. Methods: A total of 40 nickel-titanium (NiTi) wire segments (Morelli OrtodontiaTM - Sorocaba, SP, Brazil), 0.016-in in diameter were used. Groups were sorted according to lot numbers (lots 1, 2, 3 and 4). 28-mm length segments from the straight portion (ends) of archwires were used. Deflection tests were performed in an EMIC universal testing machine with 5-N load cell at 1 mm/minute speed. Force at deactivation was recorded at 0.5, 1, 2 and 3 mm deflection. Analysis of variance (ANOVA) was used to compare differences between group means. Results: When comparing the force of groups at the same deflection (3, 2 and 1 mm), during deactivation, no statistical differences were found. Conclusion: There are no changes in the elastic properties of different lots of the same commercial brand; thus, the use of different lots of the orthodontic wires used in this research does not compromise the final outcomes of the load-deflection ratio. PMID:27007760

  5. Control of resonant frequency by currents in graphene: Effect of Dirac field on deflection

    SciTech Connect

    Soodchomshom, Bumned E-mail: fscibns@ku.ac.th

    2014-09-21

    To construct Lagrangian based on plate theory and tight-binding model, deflection-field coupling to Dirac fermions in graphene can be investigated. As have been known, deflection-induced strain may cause an effect on motion of electron, like a pseudo gauge field. In the work, we will investigate the effect of the Dirac field on the motion of the deflection-field in graphene derived from Lagrangian density. Due to the interaction of the deflection- and Dirac-fields, the current-induced surface-tension up to about 4×10⁻³ N/m in graphene membrane is predicted. This result may lead to controllable resonant frequency by currents in graphene. The high resonant frequency is found to be perfectly linearly controlled by both charge and valley currents. Our work reveals the potential of graphene for application of nano-electro-mechanical device and the physics of interaction of electron and deflection-filed in graphene system is investigated.

  6. Predicting tool operator capacity to react against torque within acceptable handle deflection limits in automotive assembly.

    PubMed

    Radwin, Robert G; Chourasia, Amrish; Fronczak, Frank J; Subedi, Yashpal; Howery, Robert; Yen, Thomas Y; Sesto, Mary E; Irwin, Curtis B

    2016-05-01

    The proportion of tool operators capable of maintaining published psychophysically derived threaded fastener tool handle deflection limits were predicted using a biodynamic tool operator model, interacting with the tool, task and workstation. Tool parameters, including geometry, speed and torque were obtained from the specifications for 35 tools used in an auto assembly plant. Tool mass moments of inertia were measured for these tools using a novel device that engages the tool in a rotating system of known inertia. Task parameters, including fastener target torque and joint properties (soft, medium or hard), were ascertained from the vehicle design specifications. Workstation parameters, including vertical and horizontal distances from the operator were measured using a laser rangefinder for 69 tool installations in the plant. These parameters were entered into the model and tool handle deflection was predicted for each job. While handle deflection for most jobs did not exceed the capacity of 75% females and 99% males, six jobs exceeded the deflection criterion. Those tool installations were examined and modifications in tool speed and operator position improved those jobs within the deflection limits, as predicted by the model. We conclude that biodynamic tool operator models may be useful for identifying stressful tool installations and interventions that bring them within the capacity of most operators. PMID:26851480

  7. Solution precursor plasma deposition of nanostructured CdS thin films

    SciTech Connect

    Tummala, Raghavender; Guduru, Ramesh K.; Mohanty, Pravansu S.

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer Inexpensive process with capability to produce large scale nanostructured coatings. Black-Right-Pointing-Pointer Technique can be employed to spray the coatings on any kind of substrates including polymers. Black-Right-Pointing-Pointer The CdS coatings developed have good electrical conductivity and optical properties. Black-Right-Pointing-Pointer Coatings possess large amount of particulate boundaries and nanostructured grains. -- Abstract: Cadmium sulfide (CdS) films are used in solar cells, sensors and microelectronics. A variety of techniques, such as vapor based techniques, wet chemical methods and spray pyrolysis are frequently employed to develop adherent CdS films. In the present study, rapid deposition of CdS thin films via plasma spray route using a solution precursor was investigated, for the first time. Solution precursor comprising cadmium chloride, thiourea and distilled water was fed into a DC plasma jet via an axial atomizer to create ultrafine droplets for instantaneous and accelerated thermal decomposition in the plasma plume. The resulting molten/semi-molten ultrafine/nanoparticles of CdS eventually propel toward the substrate to form continuous CdS films. The chemistry of the solution precursor was found to be critical in plasma pyrolysis to control the stoichiometry and composition of the films. X-ray diffraction studies confirmed hexagonal {alpha}-CdS structure. Surface morphology and microstructures were investigated to compare with other synthesis techniques in terms of process mechanism and structural features. Transmission electron microscopy studies revealed nanostructures in the atomized particulates. Optical measurements indicated a decreasing transmittance in the visible light with increasing the film thickness and band gap was calculated to be {approx}2.5 eV. The electrical resistivity of the films (0.243 {+-} 0.188 Multiplication-Sign 10{sup 5} {Omega} cm) was comparable with the literature

  8. Gas separating

    DOEpatents

    Gollan, Arye

    1988-01-01

    Feed gas is directed tangentially along the non-skin surface of gas separation membrane modules comprising a cylindrical bundle of parallel contiguous hollow fibers supported to allow feed gas to flow from an inlet at one end of a cylindrical housing through the bores of the bundled fibers to an outlet at the other end while a component of the feed gas permeates through the fibers, each having the skin side on the outside, through a permeate outlet in the cylindrical casing.

  9. Gas separating

    DOEpatents

    Gollan, Arye Z.

    1990-12-25

    Feed gas is directed tangentially along the non-skin surface of gas separation membrane modules comprising a cylindrical bundle of parallel contiguous hollow fibers supported to allow feed gas to flow from an inlet at one end of a cylindrical housing through the bores of the bundled fibers to an outlet at the other end while a component of the feed gas permeates through the fibers, each having the skin side on the outside, through a permeate outlet in the cylindrical casing.

  10. Separation system

    DOEpatents

    Rubin, Leslie S.

    1986-01-01

    A separation system for dewatering radioactive waste materials includes a disposal container, drive structure for receiving the container, and means for releasably attaching the container to the drive structure. Separation structure disposed in the container adjacent the inner surface of the side wall structure retains solids while allowing passage of liquids. Inlet port structure in the container top wall is normally closed by first valve structure that is centrifugally actuated to open the inlet port and discharge port structure at the container periphery receives liquid that passes through the separation structure and is normally closed by second valve structure that is centrifugally actuated to open the discharge ports. The container also includes coupling structure for releasable engagement with the centrifugal drive structure. Centrifugal force produced when the container is driven in rotation by the drive structure opens the valve structures, and radioactive waste material introduced into the container through the open inlet port is dewatered, and the waste is compacted. The ports are automatically closed by the valves when the container drum is not subjected to centrifugal force such that containment effectiveness is enhanced and exposure of personnel to radioactive materials is minimized.

  11. Component separations.

    PubMed

    Heller, Lior; McNichols, Colton H; Ramirez, Oscar M

    2012-02-01

    Component separation is a technique used to provide adequate coverage for midline abdominal wall defects such as a large ventral hernia. This surgical technique is based on subcutaneous lateral dissection, fasciotomy lateral to the rectus abdominis muscle, and dissection on the plane between external and internal oblique muscles with medial advancement of the block that includes the rectus muscle and its fascia. This release allows for medial advancement of the fascia and closure of up to 20-cm wide defects in the midline area. Since its original description, components separation technique underwent multiple modifications with the ultimate goal to decrease the morbidity associated with the traditional procedure. The extensive subcutaneous lateral dissection had been associated with ischemia of the midline skin edges, wound dehiscence, infection, and seroma. Although the current trend is to proceed with minimally invasive component separation and to reinforce the fascia with mesh, the basic principles of the techniques as described by Ramirez et al in 1990 have not changed over the years. Surgeons who deal with the management of abdominal wall defects are highly encouraged to include this technique in their collection of treatment options. PMID:23372455

  12. Simultaneous Optical Measurements of Axial and Tangential Steady-State Blade Deflections

    NASA Technical Reports Server (NTRS)

    Kurkov, Anatole P.; Dhadwal, Harbans S.

    1999-01-01

    Currently, the majority of fiber-optic blade instrumentation is being designed and manufactured by aircraft-engine companies for their own use. The most commonly employed probe for optical blade deflection measurements is the spot probe. One of its characteristics is that the incident spot on a blade is not fixed relative to the blade, but changes depending on the blade deformation associated with centrifugal and aerodynamic loading. While there are geometrically more complicated optical probe designs in use by different engine companies, this paper offers an alternate solution derived from a probe-mount design feature that allows one to change the probe axial position until the incident spot contacts either a leading or a trailing edge. By tracing the axial position of either blade edge one is essentially extending the deflection measurement to two dimensions, axial and tangential. The blade deflection measurements were obtained during a wind tunnel test of a fan prototype.

  13. Large deflection of clamped circular plate and accuracy of its approximate analytical solutions

    NASA Astrophysics Data System (ADS)

    Zhang, Yin

    2016-02-01

    A different set of governing equations on the large deflection of plates are derived by the principle of virtual work (PVW), which also leads to a different set of boundary conditions. Boundary conditions play an important role in determining the computation accuracy of the large deflection of plates. Our boundary conditions are shown to be more appropriate by analyzing their difference with the previous ones. The accuracy of approximate analytical solutions is important to the bulge/blister tests and the application of various sensors with the plate structure. Different approximate analytical solutions are presented and their accuracies are evaluated by comparing them with the numerical results. The error sources are also analyzed. A new approximate analytical solution is proposed and shown to have a better approximation. The approximate analytical solution offers a much simpler and more direct framework to study the plate-membrane transition behavior of deflection as compared with the previous approaches of complex numerical integration.

  14. Flame four-dimensional deflection tomography with compressed-sensing-revision reconstruction

    NASA Astrophysics Data System (ADS)

    Zhang, Bin; Zhao, Minmin; Liu, Zhigang; Wu, Zhaohang

    2016-08-01

    Deflection tomography with limited angle projections was investigated to visualize a premixed flame. A projection sampling system for deflection tomography was used to obtain chronological deflectogram arrays at six view angles with only a pair of gratings. A new iterative reconstruction algorithm with deflection angle compressed-sensing revision was developed to improve reconstruction-distribution quality from incomplete projection data. Numerical simulation and error analysis provided a good indication of algorithm precision and convergence. In the experiment, 150 fringes were processed, and temperature distributions in 20 cross-sections were reconstructed from projection data in four instants. Four-dimensional flame structures and temperature distributions in the flame interior were visualized using the visualization toolkit. The experimental reconstruction was then compared with the result obtained from computational fluid dynamic analysis.

  15. Dynamics of Freely Oscillating and Coupled Hair Cell Bundles under Mechanical Deflection

    PubMed Central

    Fredrickson-Hemsing, Lea; Strimbu, C. Elliott; Roongthumskul, Yuttana; Bozovic, Dolores

    2012-01-01

    In vitro, attachment to the overlying membrane was found to affect the resting position of the hair cell bundles of the bullfrog sacculus. To assess the effects of such a deflection on mechanically decoupled hair bundles, comparable offsets were imposed on decoupled spontaneously oscillating bundles. Strong modulation was observed in their dynamic state under deflection, with qualitative changes in the oscillation profile, amplitude, and characteristic frequency of oscillation seen in response to stimulus. Large offsets were found to arrest spontaneous oscillation, with subsequent recovery upon reversal of the stimulus. The dynamic state of the hair bundle displayed hysteresis and a dependence on the direction of the imposed offset. The coupled system of hair bundles, with the overlying membrane left on top of the preparation, also exhibited a dependence on offset position, with an increase in the linear response function observed under deflections in the inhibitory direction. PMID:22768934

  16. Dynamics of freely oscillating and coupled hair cell bundles under mechanical deflection.

    PubMed

    Fredrickson-Hemsing, Lea; Strimbu, C Elliott; Roongthumskul, Yuttana; Bozovic, Dolores

    2012-04-18

    In vitro, attachment to the overlying membrane was found to affect the resting position of the hair cell bundles of the bullfrog sacculus. To assess the effects of such a deflection on mechanically decoupled hair bundles, comparable offsets were imposed on decoupled spontaneously oscillating bundles. Strong modulation was observed in their dynamic state under deflection, with qualitative changes in the oscillation profile, amplitude, and characteristic frequency of oscillation seen in response to stimulus. Large offsets were found to arrest spontaneous oscillation, with subsequent recovery upon reversal of the stimulus. The dynamic state of the hair bundle displayed hysteresis and a dependence on the direction of the imposed offset. The coupled system of hair bundles, with the overlying membrane left on top of the preparation, also exhibited a dependence on offset position, with an increase in the linear response function observed under deflections in the inhibitory direction. PMID:22768934

  17. Close-Range Photogrammetric Measurement of Static Deflections for an Aeroelastic Supercritical Wing

    NASA Technical Reports Server (NTRS)

    Byrdsong, Thomas A.; Adams, Richard R.; Sandford, Maynard C.

    1990-01-01

    Close range photogrammetric measurements were made for the lower wing surface of a full span aspect ratio 10.3 aeroelastic supercritical research wing. The measurements were made during wind tunnel tests for quasi-steady pressure distributions on the wing. The tests were conducted in the NASA Langley Transonic Dynamics Tunnel at Mach numbers up to 0.90 and dynamic pressures up to 300 pounds per square foot. Deflection data were obtained for 57 locations on the wing lower surface using dual non-metric cameras. Representative data are presented as graphical overview to show variations and trends of spar deflection with test variables. Comparative data are presented for photogrammetric and cathetometric results of measurements for the wing tip deflections. A tabulation of the basic measurements is presented in a supplement to this report.

  18. Deflection Analysis of the Space Shuttle External Tank Door Drive Mechanism

    NASA Technical Reports Server (NTRS)

    Tosto, Michael A.; Trieu, Bo C.; Evernden, Brent A.; Hope, Drew J.; Wong, Kenneth A.; Lindberg, Robert E.

    2008-01-01

    Upon observing an abnormal closure of the Space Shuttle s External Tank Doors (ETD), a dynamic model was created in MSC/ADAMS to conduct deflection analyses for assessing whether the Door Drive Mechanism (DDM) was subjected to excessive additional stress, and more importantly, to evaluate the magnitude of the induced step or gap with respect to shuttle s body tiles. To model the flexibility of the DDM, a lumped parameter approximation was used to capture the compliance of individual parts within the drive linkage. These stiffness approximations were then validated using FEA and iteratively updated in the model to converge on the actual distributed parameter equivalent stiffnesses. The goal of the analyses is to determine the deflections in the mechanism and whether or not the deflections are in the region of elastic or plastic deformation. Plastic deformation may affect proper closure of the ETD and would impact aero-heating during re-entry.

  19. Spatially-resolved investigation of transport in semiconductors: a photothermal deflection approach

    SciTech Connect

    Skumanich, A.; Fournier, D.; Boccara, A.C.; Amer, N.M.

    1985-06-01

    The unique ability of photothermal deflection spectroscopy to probe the local index of refraction of matter is exploited to investigate, in a spatially-resolved manner, thermal and electronic transport in semiconductors. An added advantage of this approach is that it is contactless; hence, it obviates the classical problems associated with electrodes and contacts. The basic premise of the technique is the use of the heat associated with non-radiative processes (e.g., recombination of carriers) to deflect a focussed laser probe beam (sub-gap energy) propagating through the semiconductor. The deflection of the probe beam is caused by a change in the refractive index of the sample which is in turn governed by carrier diffusion and recombination.

  20. Velocimetry in laminar and turbulent flows using the photothermal deflection effect with a transient grating.

    PubMed

    Dasch, C J; Sell, J A

    1986-10-01

    An enhanced-precision, high-signal method for velocity measurements with photothermal deflection spectroscopy is presented. A transient refractive-index grating is formed by the interference of two pulsed, pump-laser beams in an absorbing gas. The motion of the grating is detected by the oscillatory deflection of a probe beam, which has a diameter smaller than the fringe spacing. This two-beam pump improves on single-beam pumps because there are more markers for the velocity determination, and the larger thermal gradients increase the probe deflection. The method is illustrated by velocity maps in a laminar ethylene/nitrogen jet using a CO(2) pump laser. Velocity distributions and noise levels were also measured with grid-induced turbulence above the jet. PMID:19738701

  1. Gravitational lensing from compact bodies: Analytical results for strong and weak deflection limits

    SciTech Connect

    Amore, Paolo; Cervantes, Mayra; De Pace, Arturo; Fernandez, Francisco M.

    2007-04-15

    We develop a nonperturbative method that yields analytical expressions for the deflection angle of light in a general static and spherically symmetric metric. The method works by introducing into the problem an artificial parameter, called {delta}, and by performing an expansion in this parameter to a given order. The results obtained are analytical and nonperturbative because they do not correspond to a polynomial expression in the physical parameters. Already to first order in {delta} the analytical formulas obtained using our method provide at the same time accurate approximations both at large distances (weak deflection limit) and at distances close to the photon sphere (strong deflection limit). We have applied our technique to different metrics and verified that the error is at most 0.5% for all regimes. We have also proposed an alternative approach which provides simpler formulas, although with larger errors.

  2. Multiple-mode large deflection random response of beams with nonlinear damping subjected to acoustic excitation

    NASA Technical Reports Server (NTRS)

    Prasad, C. B.; Mei, Chuh

    1987-01-01

    Multiple-mode nonlinear analysis is carried out for beams subjected to acoustic excitation. Effects of both nonlinear damping and large-deflection are included in the analysis in an attempt to explain the experimental phenomena of aircraft panels excited at high sound pressure levels; that is the broadening of the strain response peaks and the increase of modal frequency. An amplitude dependent nonlinear damping model is used in the anlaysis to study the effects and interactions of multiple modes, nonlinear stiffness and nonlinear damping on the random response of beams. Mean square maximum deflection, mean square maximum strain, and spectral density function of maximum strain for simple supported and clamped beams are obtained. It is shown analytically that nonlinear damping contributes significantly to the broadening of the response peak and to the mean square deflection and strain.

  3. Effect of canard deflection on close-coupled canard-wing-body aerodynamics

    NASA Technical Reports Server (NTRS)

    Tu, Eugene L.

    1992-01-01

    The thin-layer Navier-Stokes equations are solved for the flow about a canard-wing-body configuration at transonic Mach numbers of 0.85 and 0.90, angles of attack from -4 to 10 degrees and canard deflection angles from -10 to +10 degrees. Effects of canard deflection on aerodynamic performance, including canard-wing vortex interaction, are investigated. Comparisons with experimental measurements of surface pressures, lift, drag and pitching moments are made to verify the accuracy of the computations. The results of the study show that the deflected canard downwash not only influences the formation of the wing leading-edge vortex, but can cause the formation of an unfavorable vortex on the wing lower surface as well.

  4. Evaluating angular deflections from the digital gradient sensing method with rigid-motion deleted

    NASA Astrophysics Data System (ADS)

    Zhang, Rui

    2016-06-01

    The digital gradient sensing method is used for measuring small angular deflections of light rays due to local stresses in transparent planar solids. The method is based on two-dimensional (2D) digital image correlation (DIC) to measure the angular deflection of light rays; however, when a specimen is subjected to loading, deformation measurement from DIC is not perfect because of the existence of small in-plane and out-of-plane motions of the test sample surface that occurred after loading. These disadvantages will lead to errors in the measured angular deflections. The influence of unavoidable in-plane and out-of-plane motions was discussed, and a method to eliminate the influence to show the pure stress gradient of polymethy methacrylate is demonstrated.

  5. Surface evaluation method and stamping simulation for surface deflection of automotive outer panels

    NASA Astrophysics Data System (ADS)

    Ichijo, Naoki; Iwata, Noritoshi; Iwata, Takamichi; Mita, Taichi; Niihara, Masatomo; Tsutamori, Hideo

    2013-12-01

    In designing dies of automotive outer panels, the most difficult process is to modify surface deflection. To fabricate high-quality outer panels without modifying dies, it is important to develop an evaluation method and a numerical analysis method for surface deflection of outer panels. In this study, we have developed a new evaluation method that uses the maximum value of curvature calculated using reflecting curves in the surface. This new evaluation method made the examiner's evaluation to conform with the digital evaluation. The evaluation results with the new method shows better agreement with the sensory value than those with the conventional methods. We have proposed the new analysis method to predict surface deflection correctly. By the proposed simulation method, plastic deformation is calculated in consideration of stress in thickness direction, and restriking conditions have been examined. We have applied our methods to the fabrication of automotive outer panels, and verified that these are useful and practical.

  6. Exploratory investigation of deflectable forebody strakes for high angle of attack yaw control

    NASA Technical Reports Server (NTRS)

    Rao, D. M.; Murri, D. G.

    1986-01-01

    A deflectable strake concept was investigated on a conical forebody to evaluate its yaw control potential at high angles of attack. In exploratory low-speed tunnel tests using a generic delta wing fighter configuration, antisymmetrically deflected strakes provided useful levels of yaw power at angles of attack when the conventional rudder became totally degraded. Symmetrical strakes prevented side force development at high angles of attack, and provided pitch control through symmetrical deflection. The strake performance was sensitive to its circumferential position on the forebody due to varying interaction of strake vortices with the wing and vertical tail. The low Reynolds number results of this study provided a favorable initial validation of the concept, subject to verification in regard to scale effects.

  7. [Spectroscopic study on CdS nanoparticles prepared by microwave irradiation].

    PubMed

    Cheng, Wei-qing; Liu, Di; Yan, Zheng-yu

    2008-06-01

    CdS nanoparticles capped by mercaptoacetic acid have been successfully synthesized by microwave method employing thioacetamide as sulfur source, which was proved to be a simple, rapid and specific mothod compared with traditional synthetical methods, such as precipitation, sol-gel, solvo-thermal method and so on. The concrete procedure synthesizing CdS nanoparticles was as follows: Cd(NO3)2 (40 mL, 5 mmol c L(-1)) was titrated with mercaptoacetic acid to pH 2.0, resulting in a turbid blue solution. NaOH (0.1 mol x L(-1)) was then added dropwise until the pH was 7 and the solution was again colorless. While quickly stirring the solution, 40 mL of 5 mmol x L(-1) CH3CSNH2 was added. Subsequently, the solution was adjusted to pH 9.0 and placed in a microwave oven for 25 min with power 30% (it means that if microwave works in a 30 s regime, it works 6 s, and does not work 24 s. This is some kind of pulse regime, but the totalpower is still 100%). This kind of nanoparticles were water-soluble and symmetrical. The diameter of CdS nanoparticles which have a spherical morphology was determined to be 12 nm by transmission electron microscopy(TEM), which posess perfect uniforminty. According to literatures report, there are two kinds of emission peak: one is edge-emission peak, and the other is surface blemish emission. In contrast to edge-emission peak, the surface blemish emission shows red shift on fluorescence spectra. In the present paper, the prominent peak of CdS QDs fluorescence spectrum was located at 490 nm, the humpbacked peak caused by surface blemish of CdS nanoparticles was located at 565 nm. However, the surface blemish emission was unconspicuous, thus we can conclude that the synthetical CdS QDs possesses excellent luminescence capability and favorable structure. The size and absorption and fluorescence spectra of CdS nanoparticles at different microwave power, pH value, reaction time and different sulfur source were investigated. The result showed that the

  8. Beam Dynamics Studies of Parallel-Bar Deflecting Cavities

    SciTech Connect

    S. Ahmed, G. Krafft, K. Detrick, S. Silva, J. Delayen, M. Spata ,M. Tiefenback, A. Hofler ,K. Beard

    2011-03-01

    We have performed three-dimensional simulations of beam dynamics for parallel-bar transverse electromagnetic mode (TEM) type RF separators: normal- and super-conducting. The compact size of these cavities as compared to conventional TM$_{110}$ type structures is more attractive particularly at low frequency. Highly concentrated electromagnetic fields between the parallel bars provide strong electrical stability to the beam for any mechanical disturbance. An array of six 2-cell normal conducting cavities or a one- or two-cell superconducting structure are enough to produce the required vertical displacement at the Lambertson magnet. Both the normal and super-conducting structures show very small emittance dilution due to the vertical kick of the beam.

  9. Optical Measurements of Axial and Tangential Steady-State Blade Deflections Obtained Simultaneously

    NASA Technical Reports Server (NTRS)

    Kurkov, Anatole P.; Dhadwal, Harbans S.

    2000-01-01

    Case-mounted fiber-optic sensors have been used by aircraft engine manufacturers mainly to monitor blade vibration in fans and compressors. The simplest probe arrangement is a spot probe where, typically, a center fiber transmits laser light, and the outer fibers collect the reflected light from the blade tips and transmit it to a photodetector. Because the spot of incident light is fixed in space, whereas the blade deflects dynamically, the reflected light will originate from slightly different portions of the blade tip under different operating conditions. Unless corrections are developed to compensate for this effect, some error in vibratory tangential amplitude will occur. For monitoring vibrations, this error is usually not critical. However, when steady-state blade deflections are being measured, it is very important to fix the spot on the blade tip at a particular location because the operating speed blade deflections are evaluated against a low-speed reference run. The change in speed usually implies a significant change in the blade orientation and possibly its shape brought about by the aerodynamic and centrifugal loading. It is most convenient to select the blade s leading and trailing edges as the fixed points for which deflections will be evaluated. To capture the blade edges at various speeds, the light probe must be movable. This was achieved by mounting the probe in an eccentric hole in a bushing that fit the fan case in the region that overlapped the path of the blade edge. The probe was actuated to search for a blade edge while all the blades were viewed on an oscilloscope. The blade edge was considered to be captured when a pulse associated with a particular blade was significantly reduced in magnitude but was clearly distinguishable from the background noise level. By tracing the axial position of either blade edge, one could extend the deflection measurement to two dimensions: axial and tangential. These blade deflection measurements were

  10. Deflection estimation of a wind turbine blade using FBG sensors embedded in the blade bonding line

    NASA Astrophysics Data System (ADS)

    Kim, Sang-Woo; Kang, Woo-Ram; Jeong, Min-Soo; Lee, In; Kwon, Il-Bum

    2013-12-01

    Estimating the deflection of flexible composite wind turbine blades is very important to prevent the blades from hitting the tower. Several researchers have used fiber Bragg grating (FBG) sensors—a type of optical fiber sensor (OFS)—to monitor the structural behavior of the blades. They can be installed on the surface and/or embedded in the interior of composites. However, the typical installation positions of OFSs present several problems, including delamination of sensing probes and a higher risk of fiber breakage during installation. In this study, we proposed using the bonding line between the shear web and spar cap as a new installation position of embedded OFSs for estimating the deflection of the blades. Laboratory coupon tests were undertaken preliminarily to confirm the strain measuring capability of embedded FBG sensors in adhesive layers, and the obtained values were verified by comparison with results obtained by electrical strain gauges and finite element analysis. We performed static loading tests on a 100 kW composite wind turbine blade to evaluate its deflections using embedded FBG sensors positioned in the bonding line. The deflections were estimated by classical beam theory considering a rigid body rotation near the tip of the blade. The evaluated tip deflections closely matched those measured by a linear variable differential transformer. Therefore, we verified the capability of embedded FBG sensors for evaluating the deflections of wind turbine blades. In addition, we confirmed that the bonding line between the shear web and spar cap is a practical location to embed the FBG sensors.

  11. ForeCAT: Using CME Deflections to Constrain their Mass and the Drag

    NASA Astrophysics Data System (ADS)

    Kay, C.; dos Santos, L. F. G.; Opher, M.

    2014-12-01

    Observations show that CMEs can deflect from a purely radial trajectory yet no consensus exists as to the cause of these deflections. The majority of the deflection motion occurs in the corona at distances where the magnetic energy dominates. Accordingly, many theories attribute the CME deflection to magnetic forces. In Kay et al. (2013) we presented ForeCAT, a model for CME deflections based on the magnetic forces (magnetic tension and magnetic pressure gradients). Kay et al. (2014) introduced an improved three-dimensional version of ForeCAT. Here we study the 2008 December 12 CME which occurred during solar minimum of Solar Cycle 24 (Byrne et al 2010, Gui et al. 2011, Liu et al 2010a,b). This CME erupted from high latitudes, and, despite the weak background magnetic field, deflected to the ecliptic, impacting Earth. From the observations, we are able to constrain all of the ForeCAT input parameters except for the CME mass and the drag coefficient that affects the CME motion. The reduced chi-square best fit to the observations constrains the CME mass range to 3e14 to 7e14 g and the drag coefficient range to 1.9 to 2.4. We explore the effects of a different magnetic background which decreases less rapidly than our standard Potential Field Source Surface (PFSS) model, as type II radio bursts suggest that the PFSS magnetic field decays too rapidly above active regions. For the case of the filament eruption of 2008 December 12 we find that the quiet sun coronal magnetic field should behave similar to the PFSS model. Finally, we present our current work exploring the case of the 2008 April 9 CME.

  12. Gravitational deflection of light and massive particles by a moving Kerr-Newman black hole

    NASA Astrophysics Data System (ADS)

    He, Guansheng; Lin, Wenbin

    2016-05-01

    The gravitational deflection of test particles including light, due to a radially moving Kerr-Newman (KN) black hole with an arbitrary constant velocity that is perpendicular to its angular momentum, is investigated. In harmonic coordinates, we derive the second post-Minkowskian (2PM) equations of motion for test particles, and solve them by high-accuracy numerical calculations. We then concentrate on discussing the kinematical corrections caused by the motion of the gravitational source to second-order deflection. The analytical formula of the light-deflection angle up to the second order by a moving lens is obtained. For a massive particle moving with a relativistic velocity, there are two different analytical results for the Schwarzschild deflection angle up to the second order reported in the previous works, i.e. α (w)=2≤ft(1+\\tfrac{1}{{w}2}\\right)\\tfrac{M}{b}+3π ≤ft(\\tfrac{1}{4}+\\tfrac{1}{{w}2}\\right)\\tfrac{{M}2}{{b}2} and α (w)=2≤ft(1+\\tfrac{1}{{w}2}\\right)\\tfrac{M}{b}+≤ft[3π ≤ft(\\tfrac{1}{4}+\\tfrac{1}{{w}2}\\right)+2≤ft(1-\\tfrac{1}{{w}4}\\right)\\right]\\tfrac{{M}2}{{b}2}, where M, b, and w are the mass of the lens, the impact parameter, and the particle’s initial velocity, respectively. Our numerical result is in perfect agreement with the former result. Furthermore, the analytical formula for massive particle deflection up to the second order in the Kerr geometry is achieved. Finally, the possibilities of detecting the motion effects on the second-order deflection are also analyzed.

  13. Wavelength-tunable lasing in single-crystal CdS1-XSeX nanoribbons

    NASA Astrophysics Data System (ADS)

    Liu, Y. K.; Zapien, J. A.; Shan, Y. Y.; Tang, H.; Lee, C. S.; Lee, S. T.

    2007-09-01

    Alloyed ternary CdS1-XSeX nanoribbons of variable composition X were synthesized by the combination of thermal evaporation and laser ablation. High-resolution transmission electron microscopy and x-ray diffraction showed that the ternary CdS1-XSeX nanoribbons were single phase and highly crystalline. Room-temperature optical measurements showed that band-gap engineering could be realized in CdS1-XSeX nanoribbons via modulation in composition X. Lasing emission between the band-gap energy of CdS (512 nm) and that of CdSe (710 nm) was observed for composition 0CdS1-XSeX nanoribbons reveal the uniform optical properties of the nanoribbons, which supports the absence of phase segregation within the nanoribbon. Fine tuning of the lasing wavelength via composition changes is shown to be smaller than 0.1 nm, and is capable of overlapping thermally induced tuning, demonstrating the possibility of continuous tuning in the lasing wavelength. The broad and fine tunable lasing properties of ternary nanoribbons have potential applications in color-tuned nanolasers, biological labels, and nano-optoelectronics.

  14. In situ growth of well-dispersed CdS nanocrystals in semiconducting polymers

    PubMed Central

    2013-01-01

    A straight synthetic route to fabricate hybrid nanocomposite films of well-dispersed CdS nanocrystals (NCs) in poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) is reported. A soluble cadmium complex [Cd(SBz)2]2·MI, obtained by incorporating a Lewis base (1-methylimidazole, MI) on the cadmium bis(benzyl)thiol, is used as starting reagent in an in situ thermolytic process. CdS NCs with spherical shape nucleate and grow well below 200°C in a relatively short time (30 min). Photoluminescence spectroscopy measurements performed on CdS/MEH-PPV nanocomposites show that CdS photoluminescence peaks are totally quenched inside MEH-PPV, if compared to CdS/PMMA nanocomposites, as expected due to overlapping of the polymer absorption and CdS emission spectra. The CdS NCs are well-dispersed in size and homogeneously distributed within MEH-PPV matrix as proved by transmission electron microscopy. Nanocomposites with different precursor/polymer weight ratios were prepared in the range from 1:4 to 4:1. Highly dense materials, without NCs clustering, were obtained for a weight/weight ratio of 2:3 between precursor and polymer, making these nanocomposites particularly suitable for optoelectronic and solar energy conversion applications. PMID:24015753

  15. Synthesis of Novel Sea-Urchin-Like CdS and Their Optical Properties.

    PubMed

    Kamran, Muhammad Arshad; Liu, Ruibin; Shi, Li-Jie; Bukhtiar, Arfan; Li, Jing; Zou, Bingsuo

    2015-06-01

    A novel morphology of CdS sea-urchin-like microstructures is synthesized by simple thermal evaporation process. Microstructures with average size of 20-50 μm are composed of single crystalline CdS nanobelts. The structural, compositional, morphological characterization of the product were examined by X-ray diffraction, energy dispersive X-ray spectroscopy, Raman spectroscopy, scanning electron microscope, transmission electron microscopy and selected area electron diffraction while optical properties are investigated by Photoluminescence spectroscopy and time-resolved Photoluminescence measurements. The tentative growth mechanism for the growth of sea-urchin-like CdS is proposed and described briefly. A strong green emission with a maximum around 517 nm was observed from the individual CdS microstructure at room temperature, which was attributed to band-edge emission of CdS. These Novel structures exhibit excellent lasing (stimulated emission) with low threshold (9.07 μJ cm(-2)) at room temperature. We analyze the physical mechanism of stimulated emission. These results are important in the design of green luminescence, low-threshold laser and display devices in the future. PMID:26369062

  16. In situ synthesis of mesoporous CdS nanoparticles in ternary cubic phase lyotropic liquid crystal

    NASA Astrophysics Data System (ADS)

    Huang, N. M.; Kan, C. S.; Radiman, S.

    An in situ technique for the synthesis of CdS nanoparticles in a ternary lyotropic cubic phase liquid crystal has been carried out. The extremely viscous cubic phase liquid-crystal system consists of poly(oxyethylene)10 nonyl phenol ether as non-ionic surfactant, octane as oil phase and an aqueous phase containing reactant ions (Cd2+ and S2-). Thioacetamide (TAA) has been utilized as a source for slow release of sulfur in the in situ synthesis of CdS. Rheological results show that CdS nanoparticle growth did not disrupt the structure of the cubic phase liquid-crystal system. This indicates that homogenous synthesis of CdS in the liquid crystal had been achieved. The final products were characterized using X-ray photoelectron spectroscopy, thermal gravimetric analysis, transmission electron microscopy and UV-visible spectroscopy. It was found that the CdS nanoparticles formed have a mesoporous structure with a size dependent on the TAA decomposition aging time.

  17. Combinatorial Chemical Bath Deposition of CdS Contacts for Chalcogenide Photovoltaics.

    PubMed

    Mokurala, Krishnaiah; Baranowski, Lauryn L; de Souza Lucas, Francisco W; Siol, Sebastian; van Hest, Maikel F A M; Mallick, Sudhanshu; Bhargava, Parag; Zakutayev, Andriy

    2016-09-12

    Contact layers play an important role in thin film solar cells, but new material development and optimization of its thickness is usually a long and tedious process. A high-throughput experimental approach has been used to accelerate the rate of research in photovoltaic (PV) light absorbers and transparent conductive electrodes, however the combinatorial research on contact layers is less common. Here, we report on the chemical bath deposition (CBD) of CdS thin films by combinatorial dip coating technique and apply these contact layers to Cu(In,Ga)Se2 (CIGSe) and Cu2ZnSnSe4 (CZTSe) light absorbers in PV devices. Combinatorial thickness steps of CdS thin films were achieved by removal of the substrate from the chemical bath, at regular intervals of time, and in equal distance increments. The trends in the photoconversion efficiency and in the spectral response of the PV devices as a function of thickness of CdS contacts were explained with the help of optical and morphological characterization of the CdS thin films. The maximum PV efficiency achieved for the combinatorial dip-coating CBD was similar to that for the PV devices processed using conventional CBD. The results of this study lead to the conclusion that combinatorial dip-coating can be used to accelerate the optimization of PV device performance of CdS and other candidate contact layers for a wide range of emerging absorbers. PMID:27479495

  18. Synthesis of CdS nanostructures using template-assisted ammonia-free chemical bath deposition

    NASA Astrophysics Data System (ADS)

    Preda, N.; Enculescu, M.; Gherendi, F.; Matei, E.; Toimil-Molares, M. E.; Enculescu, I.

    2012-09-01

    CdS micro- and nano-structures (micro/nanotubes and nanostructured films) were obtained by ammonia-free chemical bath deposition using polymer templates (ion track-etched polycarbonate membranes and poly(styrene-hydroxyethyl methacrylate) nanosphere arrays). The semiconductor structures were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), optical absorption, photoluminescence and electrical measurements. The diameters of CdS tubes are between 300 nm and few microns and the lengths are up to tens of micrometers. The SEM images prove that the CdS films are nanostructured due to the deposition on the polymer nanosphere arrays. For both CdS structures (tubes and films) the XRD patterns show a hexagonal phase. The optical studies reveal a band gap value of about 2.5-2.6 eV and a red luminescence at ˜1.77 eV. A higher increase of conductivity is observed for illuminating the CdS nanostructured film when compared to the simple semiconductor film. This is a consequence of the periodic patterning induced by the polymer nanosphere array.

  19. Scalable economic extracellular synthesis of CdS nanostructured particles by a non-pathogenic thermophile.

    PubMed

    Moon, Ji-Won; Ivanov, Ilia N; Duty, Chad E; Love, Lonnie J; Rondinone, Adam J; Wang, Wei; Li, Yi-Liang; Madden, Andrew S; Mosher, Jennifer J; Hu, Michael Z; Suresh, Anil K; Rawn, Claudia J; Jung, Hyunsung; Lauf, Robert J; Phelps, Tommy J

    2013-11-01

    We report microbially facilitated synthesis of cadmium sulfide (CdS) nanostructured particles (NP) using anaerobic, metal-reducing Thermoanaerobacter sp. The extracellular CdS crystallites were <10 nm in size with yields of ~3 g/L of growth medium/month with demonstrated reproducibility and scalability up to 24 L. During synthesis, Thermoanaerobacter cultures reduced thiosulfate and sulfite salts to H₂S, which reacted with Cd²⁺ cations to produce thermodynamically favored NP in a single step at 65 °C with catalytic nucleation on the cell surfaces. Photoluminescence (PL) analysis of dry CdS NP revealed an exciton-dominated PL peak at 440 nm, having a narrow full width at half maximum of 10 nm. A PL spectrum of CdS NP produced by dissimilatory sulfur reducing bacteria was dominated by features associated with radiative exciton relaxation at the surface. High reproducibility of CdS NP PL features important for scale-up conditions was confirmed from test tubes to 24 L batches at a small fraction of the manufacturing cost associated with conventional inorganic NP production processes. PMID:24005990

  20. Scalable economic extracellular synthesis of CdS nanostructured particles by a non-pathogenic thermophile

    SciTech Connect

    Moon, Ji Won; Ivanov, Ilia N; Duty, Chad E; Love, Lonnie J; Rondinone, Adam Justin; Wang, Wei; Li, Dr. Yi-Liang; Madden, Andrew; Mosher, Jennifer J; Hu, Michael Z.; Suresh, Anil K; Rawn, Claudia J; Jung, Hyunsung; Lauf, Robert J; Phelps, Tommy Joe

    2013-01-01

    We report microbially facilitated synthesis of cadmium sulfide (CdS) nanostructured particles (NP) using anaerobic, metal-reducing Thermoanaerobacter sp. The extracellular CdS crystallites were <10 nm in size with yields of ~3 g/L of growth medium/month with demonstrated reproducibility and scalability up to 24 L. During synthesis, Thermoanaerobacter cultures reduced thiosulfate and sulfite salts to H2S, which reacted with Cd2+ cations to produce thermodynamically favored NP in a single step at 65oC with catalytic nucleation on the cell surfaces. Photoluminescence (PL) analysis of dry CdS NP revealed an exciton-dominated PL peak at 440 nm, having a narrow full width at half maximum of 10 nm. A PL spectrum of CdS NP produced by dissimilatory sulfur reducing bacteria was dominated by features associated with radiative exciton relaxation at the surface. High reproducibility of CdS NP PL features important for scale-up conditions was confirmed from test tubes to 24L batches at a small fraction of the manufacturing cost associated with conventional inorganic NP production processes.

  1. Plasmid CDS5 influences infectivity and virulence in a mouse model of Chlamydia trachomatis urogenital infection.

    PubMed

    Ramsey, K H; Schripsema, J H; Smith, B J; Wang, Y; Jham, B C; O'Hagan, K P; Thomson, N R; Murthy, A K; Skilton, R J; Chu, P; Clarke, I N

    2014-08-01

    The native plasmid of both Chlamydia muridarum and Chlamydia trachomatis has been shown to control virulence and infectivity in mice and in lower primates. We recently described the development of a plasmid-based genetic transformation protocol for Chlamydia trachomatis that for the first time provides a platform for the molecular dissection of the function of the chlamydial plasmid and its individual genes or coding sequences (CDS). In the present study, we transformed a plasmid-free lymphogranuloma venereum isolate of C. trachomatis, serovar L2, with either the original shuttle vector (pGFP::SW2) or a derivative of pGFP::SW2 carrying a deletion of the plasmid CDS5 gene (pCDS5KO). Female mice were inoculated with these strains either intravaginally or transcervically. We found that transformation of the plasmid-free isolate with the intact pGFP::SW2 vector significantly enhanced infectivity and induction of host inflammatory responses compared to the plasmid-free parental isolate. Transformation with pCDS5KO resulted in infection courses and inflammatory responses not significantly different from those observed in mice infected with the plasmid-free isolate. These results indicate a critical role of plasmid CDS5 in in vivo fitness and in induction of inflammatory responses. To our knowledge, these are the first in vivo observations ascribing infectivity and virulence to a specific plasmid gene. PMID:24866804

  2. Plasmid CDS5 Influences Infectivity and Virulence in a Mouse Model of Chlamydia trachomatis Urogenital Infection

    PubMed Central

    Schripsema, J. H.; Smith, B. J.; Wang, Y.; Jham, B. C.; O'Hagan, K. P.; Thomson, N. R.; Murthy, A. K.; Skilton, R. J.; Chu, P.; Clarke, I. N.

    2014-01-01

    The native plasmid of both Chlamydia muridarum and Chlamydia trachomatis has been shown to control virulence and infectivity in mice and in lower primates. We recently described the development of a plasmid-based genetic transformation protocol for Chlamydia trachomatis that for the first time provides a platform for the molecular dissection of the function of the chlamydial plasmid and its individual genes or coding sequences (CDS). In the present study, we transformed a plasmid-free lymphogranuloma venereum isolate of C. trachomatis, serovar L2, with either the original shuttle vector (pGFP::SW2) or a derivative of pGFP::SW2 carrying a deletion of the plasmid CDS5 gene (pCDS5KO). Female mice were inoculated with these strains either intravaginally or transcervically. We found that transformation of the plasmid-free isolate with the intact pGFP::SW2 vector significantly enhanced infectivity and induction of host inflammatory responses compared to the plasmid-free parental isolate. Transformation with pCDS5KO resulted in infection courses and inflammatory responses not significantly different from those observed in mice infected with the plasmid-free isolate. These results indicate a critical role of plasmid CDS5 in in vivo fitness and in induction of inflammatory responses. To our knowledge, these are the first in vivo observations ascribing infectivity and virulence to a specific plasmid gene. PMID:24866804

  3. Study on the fluorescence resonance energy transfer between CdS quantum dots and Eosin Y.

    PubMed

    Yan, Zhengyu; Zhang, Zhengwei; Yu, Yan; Chen, Jianqiu

    2015-03-01

    Water-soluble CdS quantum dots (QDs) were prepared using mercaptoacetic acid (TGA) as the stabilizer in an aqueous system. A fluorescence resonance energy transfer (FRET) system was constructed between water-soluble CdS QDs (donor) and Eosin Y (acceptor). Several factors that impacted the fluorescence spectra of the FRET system, such as pH (3.05-10.10), concentration of Eosin Y (2-80 mg/L) and concentration of CdS QDs (2-80 mg/L), were investigated and refined. Donor-to-acceptor ratios, the energy transfer efficiency (E) and the distance (r) between CdS QDs and Eosin Y were obtained. The results showed that a FRET system could be established between water-soluble CdS QDs and Eosin Y at pH 5.0; donor-to-acceptor ratios demonstrated a 1: 8 proportion of complexes; the energy transfer efficiency (E) and the distance (r) between the QDs and Eosin Y were 20.07% and 4.36 nm,respectively. PMID:24888328

  4. Optical characterization of CdS semiconductor nanoparticles capped with starch

    NASA Astrophysics Data System (ADS)

    Rodríguez-Fragoso, P.; de la Cruz, G. González; Tomas, S. A.; Zelaya-Angel, O.

    2010-11-01

    Starch capped cadmium sulfide (CdS) nanoparticles were synthesized by aqueous solution precipitation. Starch added during the synthesis of nanoparticles resulted in cadmium-rich nanoparticles forming a stable complex with starch. The size of the CdS quantum dots was measured using high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD). The average diameter (d) of nanoparticles spanned the range 4.8 ± 0.4 to 5.7 ± 0.2 nm when the pH of the solution was varied within the range 10-14. The main Raman phonon of CdS, the longitudinal optical mode located around 300 cm-1, softens as diameter decreases, in accordance with theoretical predictions. In addition, the largest Raman response of starch, near 478 cm-1, related with the important skeletal vibration modes of the starch pyranose ring, dominates the spectra of the CdS capped nanoparticles and also softens as the size decreases. This fact indicates a strain variation on CdS as a function of d which increases as the pH increases.

  5. Prototype tramp-metal separator: A summary of test results

    NASA Astrophysics Data System (ADS)

    Bolczak, R.

    1982-11-01

    The test program on the prototype tramp metal separator (PTMS) consists of three stages. Typical municipal solid waste feedstocks that had undergone size reduction and trommeling were analyzed to determine their physical characteristics and to obtain samples of tramp metal. Tests were performed on individual particles to determine relevant aerodynamic properties. The PTMS was used to measure the deflections of selected particles and feedstocks dropped through the horizontal airstream.

  6. Prototype tramp-metal separator: a summary of test results

    SciTech Connect

    Bolczak, R.

    1982-11-01

    The test program on the prototype tramp metal separator (PTMS) consists of three stages. Typical municipal solid waste feedstocks that had undergone size reduction and trommeling were analyzed to determine their physical characteristics and to obtain samples of tramp metal. Tests were performed on individual particles to determine relevant aerodynamic properties. The PTMS was used to measure the deflections of selected particles and feedstocks dropped through the horizontal airstream. (LEW)

  7. Large Deflection of Ideal Pseudo-Elastic Shape Memory Alloy Cantilever Beam

    NASA Astrophysics Data System (ADS)

    Cui, Shitang; Hu, Liming; Yan, Jun

    This paper deals with the large deflections of pseudo-elastic shape memory alloy cantilever beams subjected to a concentrated load at the free end. Because of the large deflections, geometry nonlinearity arises and this analysis employs the nonlinear bending theory. The exact expression of curvature is used in the moment-curvature relationship. As a vertical force at the tip of cantilever, curvature and bending moment distribution expressions are deduced. The curvature changed distinctly when the surface material undergoes phase transformation. The length of phase transformation region was affected greatly with the force at the free end.

  8. Determination of vertical deflections using the global positioning system and geodetic leveling

    SciTech Connect

    Solar, T.; Carlson, A.E. Jr.; Evans, A.G.

    1989-07-01

    The capabilities of the Global Positioning System (GPS) for accurately determining geodetic quantities are well established. Nevertheless, no comparison between deflections of the vertical as determined through GPS with leveling and values conventionally computer by astrogeodetic methods has yet been published. This investigation demonstrates that the accurate deflections of the vertical components ({eta}, {xi}) can be obtained independently of classical astronomic observations by combining geodetic leveling with satellite GOS positioning. The approach uses a radial configuration of baselines to determine the best (in a least square sense) values of ({eta}, {xi}) at the central station.

  9. Asteroid Impact and Deflection Assessment (AIDA) mission: science investigation of a binary system and mitigation test

    NASA Astrophysics Data System (ADS)

    Michel, P.; Cheng, A. F.; Küppers, M.

    2015-10-01

    The Asteroid Impact & Deflection Assessment (AIDA) mission will be the first space experiment to investigate a binary near-Earth asteroid (NEA) and to demonstrate asteroid impact hazard mitigation by using a kinetic impactor. AIDA is a joint ESA-NASA cooperative project, which includes the ESA Asteroid Impact Mission (AIM) rendezvous spacecraft and the NASA Double Asteroid Redirection Test (DART) mission. The primary goals of AIDA are (i) to investigate the binary NEA (65803) Didymos, (ii) to test our ability to impact its moon by an hypervelocity projectile in 2022 and (iii) to measure and characterize the impact deflection both from space with AIM and from ground based observatories.

  10. North-south asymmetry in the magnetic deflection of polar coronal hole jets

    NASA Astrophysics Data System (ADS)

    Nisticò, G.; Zimbardo, G.; Patsourakos, S.; Bothmer, V.; Nakariakov, V. M.

    2015-11-01

    Context. Measurements of the sunspots area, of the magnetic field in the interplanetary medium, and of the heliospheric current sheet (HCS) position, reveal a possible north-south (N-S) asymmetry in the magnetic field of the Sun. This asymmetry could cause the bending of the HCS of the order of 5-10 deg in the southward direction, and it appears to be a recurrent characteristic of the Sun during the minima of solar activity. Aims: We study the N-S asymmetry as inferred from measurements of the deflection of polar coronal hole jets when they propagate throughout the corona. Methods: Since the corona is an environment where the magnetic pressure is greater than the kinetic pressure (β ≪ 1), we can assume that the magnetic field controls the dynamics of plasma. On average, jets follow magnetic field lines during their propagation, highlighting their local direction. We measured the position angles at 1 R⊙ and at 2 R⊙ of 79 jets, based on the Solar TErrestrial RElations Observatory (STEREO) ultraviolet and white-light coronagraph observations during the solar minimum period March 2007-April 2008. The average jet deflection is studied both in the plane perpendicular to the line of sight and, for a reduced number of jets, in 3D space. The observed jet deflection is studied in terms of an axisymmetric magnetic field model comprising dipole (g1), quadrupole (g2), and esapole (g3) moments. Results: We found that the propagation of the jets is not radial, which is in agreement with the deflection due to magnetic field lines. Moreover, the amount of the deflection is different between jets over the north and those from the south pole. A comparison of jet deflections and field line tracing shows that a ratio g2/g1 ≃ -0.5 for the quadrupole and a ratio g3/g1 ≃ 1.6-2.0 for the esapole can describe the field. The presence of a non-negligible quadrupole moment confirms the N-S asymmetry of the solar magnetic field for the considered period. Conclusions: We find that the

  11. In Situ Characterization of the Local Work Function along Individual Free Standing Nanowire by Electrostatic Deflection

    PubMed Central

    Chen, Yicong; Zhao, Chengchun; Huang, Feng; Zhan, Runze; Deng, Shaozhi; Xu, Ningsheng; Chen, Jun

    2016-01-01

    In situ characterization of the work function of quasi one dimensional nanomaterials is essential for exploring their applications. Here we proposed to use the electrostatic deflection induced by work function difference between nanoprobe and nanowire for in situ measuring the local work function along a free standing nanowire. The physical mechanism for the measurement was discussed in details and a parabolic relationship between the deflection and the potential difference was derived. As a demonstration, measurement of the local work functions on the tip and the sidewall of a ZnO nanowire with Au catalyst at its end and a LaB6 nanowire have been achieved with good accuracy. PMID:26882827

  12. Two-Screen Method for Determining Electron Beam Energy and Deflection from Laser Wakefield Acceleration

    SciTech Connect

    Pollock, B B; Ross, J S; Tynan, G R; Divol, L; Glenzer, S H; Leurent, V; Palastro, J P; Ralph, J E; Froula, D H; Clayton, C E; Marsh, K A; Pak, A E; Wang, T L; Joshi, C

    2009-04-24

    Laser Wakefield Acceleration (LWFA) experiments have been performed at the Jupiter Laser Facility, Lawrence Livermore National Laboratory. In order to unambiguously determine the output electron beam energy and deflection angle at the plasma exit, we have implemented a two-screen electron spectrometer. This system is comprised of a dipole magnet followed by two image plates. By measuring the electron beam deviation from the laser axis on each plate, both the energy and deflection angle at the plasma exit are determined through the relativistic equation of motion.

  13. Experimental measurements of rf breakdowns and deflecting gradients in mm-wave metallic accelerating structures

    NASA Astrophysics Data System (ADS)

    Dal Forno, Massimo; Dolgashev, Valery; Bowden, Gordon; Clarke, Christine; Hogan, Mark; McCormick, Doug; Novokhatski, Alexander; Spataro, Bruno; Weathersby, Stephen; Tantawi, Sami G.

    2016-05-01

    We present an experimental study of a high gradient metallic accelerating structure at sub-THz frequencies, where we investigated the physics of rf breakdowns. Wakefields in the structure were excited by an ultrarelativistic electron beam. We present the first quantitative measurements of gradients and metal vacuum rf breakdowns in sub-THz accelerating cavities. When the beam travels off axis, a deflecting field is induced in addition to the longitudinal field. We measured the deflecting forces by observing the displacement and changes in the shape of the electron bunch. This behavior can be exploited for subfemtosecond beam diagnostics.

  14. Device for characterization of thermal effusivity of liquids using photothermal beam deflection.

    PubMed

    Sandoval-Romero, G E; García-Valenzuela, A; Sánchez-Pérez, C; Hernández-Cordero, J; Muratikov, Kyrill L

    2007-10-01

    We propose and study a novel optoelectronic device for thermal characterization of materials. It is based on monitoring the photothermal deflection of a laser beam within a slab of a thermo-optic material in thermal contact with the sample under study. An optical angle sensor is used to measure the laser deflection providing a simple and experimental arrangement. We demonstrate its principle and a simple procedure to measure thermal effusivity of liquids. The proposed device could be implemented into a compact sensor head for remote measurements using electrical and fiber optic links. PMID:17979448

  15. Design of Spacecraft Missions to Test Kinetic Impact for Asteroid Deflection

    NASA Technical Reports Server (NTRS)

    Barbee, Brent W.; Hernandez, Sonia

    2012-01-01

    Earth has previously been struck with devastating force by near-Earth asteroids (NEAs) and will be struck again. Telescopic search programs aim to provide advance warning of such an impact, but no techniques or systems have yet been tested for deflecting an incoming NEA. To begin addressing this problem, we have analyzed the more than 8000 currently known NEAs to identify those that offer opportunities for safe and meaningful near-term tests of the proposed kinetic impact asteroid deflection technique. In this paper we present our methodology and results, including complete mission designs for the best kinetic impactor test mission opportunities.

  16. Deflection of Spacecraft Trajectories as a New Test of General Relativity

    SciTech Connect

    Longuski, James M.; Fischbach, Ephraim; Scheeres, Daniel J.

    2001-04-02

    We derive a simple formula which gives the general relativistic deflection of a spacecraft, idealized as a point mass, for all values of the asymptotic speed V{sub {infinity}} (0{<=}V{sub {infinity}}{<=}1) . Using this formula we suggest a new test of general relativity (GR) which can be carried out during a proposed interstellar mission that involves a close pass of the Sun. We show that, with foreseeable improvements in spacecraft tracking sensitivity, the deflection of a spacecraft's trajectory in the gravitational field of the Sun could provide a new test of GR.

  17. A finite element large deflection random response analysis of beams and plates subjected to acoustic loading

    NASA Technical Reports Server (NTRS)

    Mei, Chuh; Chiang, C. K.

    1987-01-01

    A finite element formulation is presented for the analysis of beams and rectangular plates undergoing large deflections subjected to Gaussian white noise excitations. Single-mode response is assumed in the present formulation. Root-mean-square (RMS) maximum deflections for simply supported and clamped beams and plates at various sound spectrum levels are obtained and compared with solutions using the Fokker-Planck-Kolmogorov equation and the equivalent linearization methods. RMS maximum stains and equivalent linear frequencies are compared with the equivalent linearization results for assessment of the accuracy of the finite element method.

  18. Static deflection analysis of non prismatic multilayer p-NEMS cantilevers under electrical load

    NASA Astrophysics Data System (ADS)

    Pavithra, M.; Muruganand, S.

    2016-04-01

    Deflection of Euler-Bernoulli non prismatic multilayer piezoelectric nano electromechanical (p-NEMS) cantilever beams have been studied theoretically for various profiles of p-NEMS cantilevers by applying the electrical load. This problem has been answered by applying the boundary conditions derived by simple polynomials. This method is applied for various profiles like rectangular and trapezoidal by varying the thickness of the piezoelectric layer as well as the material. The obtained results provide the better deflection for trapezoidal profile with ZnO piezo electric layer of suitable nano cantilevers for nano scale applications.

  19. An analytical solution to proton Bragg peak deflection in a magnetic field.

    PubMed

    Wolf, Russell; Bortfeld, Thomas

    2012-09-01

    The role of MR imaging for image-guided radiation therapy (IGRT) is becoming more and more important thanks to the excellent soft tissue contrast offered by MRI. Hybrid therapy devices with integrated MRI scanners are under active development for x-ray therapy. The combination of proton therapy with MRI imaging has only been investigated at the theoretical or conceptual level. Of concern is the deflection of the proton beam in the homogeneous magnetic field. A previous publication has come to the conclusion that the impact of a 0.5 T magnetic field on the dose distribution for proton therapy is very small and lateral deflections stay well below 2 mm. The purpose of this study is to provide new insights into the effects of magnetic fields on a proton beam coming to rest in a patient. We performed an analytical calculation of the lateral deflection of protons with initial energies between 50 MeV and 250 MeV, perpendicular to the beam direction and the magnetic field. We used a power-law range-energy relationship and the Lorentz force in both relativistic and non-relativistic conditions. Calculations were done for protons coming to rest in water or soft tissue, and generalized to other uniform and non-uniform media. Results were verified by comparisons with numerical calculations and Monte Carlo simulations. A key result of our calculations is that the maximum lateral deflection at the end of range is proportional to the third power of the initial energy. Accordingly, due to the strong dependence on the energy, even a relatively small magnetic field of 0.5 T will cause a deflection of the proton beam by 1 cm at the end of range of a 200 MeV beam. The maximum deflection at 200 MeV is more than 10 times larger than that of a 90 MeV beam. Relativistic corrections of the deflection are generally small but they can become non-negligible at higher energies around 200 MeV and above. Contrary to previous findings, the lateral deflection of a proton beam can be significant (1

  20. Methodology for determining elevon deflections to trim and maneuver the DAST vehicle with negative static margin

    NASA Technical Reports Server (NTRS)

    Perry, B., III

    1982-01-01

    The relationships between elevon deflection and static margin using elements from static and dynamic stability and control and from classical control theory are emphasized. Expressions are derived and presented for calculating elevon deflections required to trim the vehicle in lg straight-and-level flight and to perform specified longitudinal and lateral maneuvers. Applications of this methodology are made at several flight conditions for the ARW-2 wing. On the basis of these applications, it appears possible to trim and maneuver the vehicle with the existing elevons at -15% static margin.

  1. Laser-driven deflection arrangements and methods involving charged particle beams

    DOEpatents

    Plettner, Tomas; Byer, Robert L.

    2011-08-09

    Systems, methods, devices and apparatus are implemented for producing controllable charged particle beams. In one implementation, an apparatus provides a deflection force to a charged particle beam. A source produces an electromagnetic wave. A structure, that is substantially transparent to the electromagnetic wave, includes a physical structure having a repeating pattern with a period L and a tilted angle .alpha., relative to a direction of travel of the charged particle beam, the pattern affects the force of the electromagnetic wave upon the charged particle beam. A direction device introduces the electromagnetic wave to the structure to provide a phase-synchronous deflection force to the charged particle beam.

  2. Optical beam deflection noncontact atomic force microscope optimized with three-dimensional beam adjustment mechanism

    NASA Astrophysics Data System (ADS)

    Yokoyama, Kousuke; Ochi, Taketoshi; Uchihashi, Takayuki; Ashino, Makoto; Sugawara, Yasuhiro; Suehira, Nobuhito; Morita, Seizo

    2000-01-01

    We present a design and performance of an optical beam deflection noncontact atomic force microscope (nc-AFM). The optical deflection detection system can be optimized by the three-dimensional beam position adjustment mechanism (the slider which mounts laser diode module, the spherical rotors with mirror and the cylinder which mounts quadrant photodiode) using inertial stepping motors in an ultrahigh vacuum (UHV). The samples and cantilevers are easily exchanged in UHV. The performance of the instrument is demonstrated with the atomically resolved nc-AFM images for various surfaces such as Si(111)7×7, Cu(111), TiO2(110), and thymine/highly oriented pyrolytic graphite.

  3. Variational finite element-tensor formulation for the large deflection random vibration of composite plates

    NASA Technical Reports Server (NTRS)

    Robinson, Jay H.

    1991-01-01

    A numerical integration routine is derived from a set of unified single step integration algorithms using a weighted satisfaction of the equilibrium equation governing the large deflection random response of laminated composite plates. The equilibrium equation is derived using a constant matrix large deflection finite-element formulation. In-plane inertia terms are considered in the formulation, however, rotary inertia terms are assumed negligible. Probability density, spectral density and autocorrelation functions of the maximum displacement and strain responses are presented for three acoustic excitation levels. Classical thin plate boundary conditions and pseudo white noise excitation are used in this investigation.

  4. Unsteady-Pressure and Dynamic-Deflection Measurements on an Aeroelastic Supercritical Wing

    NASA Technical Reports Server (NTRS)

    Seidel, David A.; Sandford, Maynard C.; Eckstrom, Clinton V.

    1991-01-01

    Transonic steady and unsteady pressure tests were conducted on a large elastic wing. The wing has a supercritical airfoil, a full span aspect ratio of 10.3, a leading edge sweepback angle of 28.8 degrees, and two inboard and one outboard trailing edge control surfaces. Only the outboard control surface was deflected statically and dynamically to generate steady and unsteady flow over the wing. The unsteady surface pressure and dynamic deflection measurements of this elastic wing are presented to permit correlations of the experimental data with theoretical predictions.

  5. An analytical solution to proton Bragg peak deflection in a magnetic field

    NASA Astrophysics Data System (ADS)

    Wolf, Russell; Bortfeld, Thomas

    2012-09-01

    The role of MR imaging for image-guided radiation therapy (IGRT) is becoming more and more important thanks to the excellent soft tissue contrast offered by MRI. Hybrid therapy devices with integrated MRI scanners are under active development for x-ray therapy. The combination of proton therapy with MRI imaging has only been investigated at the theoretical or conceptual level. Of concern is the deflection of the proton beam in the homogeneous magnetic field. A previous publication has come to the conclusion that the impact of a 0.5 T magnetic field on the dose distribution for proton therapy is very small and lateral deflections stay well below 2 mm. The purpose of this study is to provide new insights into the effects of magnetic fields on a proton beam coming to rest in a patient. We performed an analytical calculation of the lateral deflection of protons with initial energies between 50 MeV and 250 MeV, perpendicular to the beam direction and the magnetic field. We used a power-law range-energy relationship and the Lorentz force in both relativistic and non-relativistic conditions. Calculations were done for protons coming to rest in water or soft tissue, and generalized to other uniform and non-uniform media. Results were verified by comparisons with numerical calculations and Monte Carlo simulations. A key result of our calculations is that the maximum lateral deflection at the end of range is proportional to the third power of the initial energy. Accordingly, due to the strong dependence on the energy, even a relatively small magnetic field of 0.5 T will cause a deflection of the proton beam by 1 cm at the end of range of a 200 MeV beam. The maximum deflection at 200 MeV is more than 10 times larger than that of a 90 MeV beam. Relativistic corrections of the deflection are generally small but they can become non-negligible at higher energies around 200 MeV and above. Contrary to previous findings, the lateral deflection of a proton beam can be significant (1

  6. Gas separating

    DOEpatents

    Gollan, A.Z.

    1990-12-25

    Feed gas is directed tangentially along the non-skin surface of gas separation membrane modules comprising a cylindrical bundle of parallel contiguous hollow fibers supported to allow feed gas to flow from an inlet at one end of a cylindrical housing through the bores of the bundled fibers to an outlet at the other end while a component of the feed gas permeates through the fibers, each having the skin side on the outside, through a permeate outlet in the cylindrical casing. 3 figs.

  7. Artwork Separation

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Under a grant from California Institute of Technology, Jet Propulsion Laboratory (JPL) and LACMA (Los Angeles County Museum of Art) used image enhancement techniques to separate x-ray images of paintings when one had been painted on top of another. The technique is derived from computer processing of spacecraft-acquired imagery, and will allow earlier paintings, some of which have been covered for centuries, to be evaluated. JPL developed the program for "subtracting" the top painting and enhancing the bottom one, and believes an even more advanced system is possible.

  8. Gas separating

    DOEpatents

    Gollan, A.

    1988-03-29

    Feed gas is directed tangentially along the non-skin surface of gas separation membrane modules comprising a cylindrical bundle of parallel contiguous hollow fibers supported to allow feed gas to flow from an inlet at one end of a cylindrical housing through the bores of the bundled fibers to an outlet at the other end while a component of the feed gas permeates through the fibers, each having the skin side on the outside, through a permeate outlet in the cylindrical casing. 3 figs.

  9. One-dimensional CdS nanostructures: a promising candidate for optoelectronics.

    PubMed

    Li, Huiqiao; Wang, Xi; Xu, Junqi; Zhang, Qi; Bando, Yoshio; Golberg, Dmitri; Ma, Ying; Zhai, Tianyou

    2013-06-11

    As a promising candidate for optoelectronics, one-dimensional CdS nanostructures have drawn great scientific and technical interest due to their interesting fundamental properties and possibilities of utilization in novel promising optoelectronical devices with augmented performance and functionalities. This progress report highlights a selection of important topics pertinent to optoelectronical applications of one-dimensional CdS nanostructures over the last five years. This article begins with the description of rational design and controlled synthesis of CdS nanostructure arrays, alloyed nanostructucures and kinked nanowire superstructures, and then focuses on the optoelectronical properties, and applications including cathodoluminescence, lasers, light-emitting diodes, waveguides, field emitters, logic circuits, memory devices, photodetectors, gas sensors, photovoltaics and photoelectrochemistry. Finally, the general challenges and the potential future directions of this exciting area of research are highlighted. PMID:23629853

  10. Solvothermal synthesis and characterization of uniform CdS nanowires in high yield

    NASA Astrophysics Data System (ADS)

    Qingqing, Wang; Gang, Xu; Gaorong, Han

    2005-09-01

    Large-scale CdS nanowires with uniform diameter and high aspect ratios were synthesized using a simple solvothermal route that employed CdCl 2 and S powder as starting materials, ethylenediamine (en) as the solvent. X-ray diffraction (XRD) pattern and transmission electron microscopy (TEM) images show that the products are hexagonal structure CdS nanowires with diameter of 40 nm and length up to 10 μm. Selected area electron diffraction (SAED) and high resolution TEM (HRTEM) studies indicate the single-crystalline nature of CdS nanowires with an oriented growth along the c-axis direction. The optical properties of the products were characterized by optical absorption spectra and photoluminescence spectra. Based on the results of contrastive experiments, it is found that the sulfur source and the solvent play significant roles in the formation of uniform nanowires. A possible formation mechanism of nanowires is discussed.

  11. Hierarchical CdS Nanowires Based Rigid and Flexible Photodetectors with Ultrahigh Sensitivity.

    PubMed

    Li, Ludong; Lou, Zheng; Shen, Guozhen

    2015-10-28

    Hierarchical CdS nanowires were synthesized via a facile vapor transport method, which were used to fabricate both rigid and flexible visible-light photodetectors. Studies found that the rigid photodetectors on SiO2/Si substrate showed ultrahigh photo-dark current ratio up to 1.96 × 10(4), several orders of magnitude higher than previously reported CdS nanostructures, as well as high specific detectivity (4.27 × 10(12) Jones), fast response speed and excellent environmental stability. Highly flexible photodetectors were also fabricated on polyimide substrate, which exhibited comparable photoresponse performance as the rigid one. In addition, the as-prepared flexible devices displayed excellent mechanical flexibility, electrical stability and folding endurance. The results indicate that the hierarchical CdS nanowires may be good candidates for nanoscale optoelectronic devices such as high-efficiency photoswitches and highly photosensitive detectors. PMID:26439364

  12. Pseudocapacitive behavior of unidirectional CdS nanoforest in 3D architecture through solution chemistry

    NASA Astrophysics Data System (ADS)

    Nair, Nikila; Majumder, Sutripto; Sankapal, Babasaheb R.

    2016-08-01

    Two step soft chemical route has been utilized for the fabrication of CdS nanowire electrode in 3D architecture at room temperature (300 K). The electrochemical pseudocapacitive behavior of thin film consisting of CdS nanowires has been evaluated by using cyclic voltammetry, charge-discharge and electrochemical impedance spectroscopy in an aqueous media. The electrochemical test revealed that CdS nanowire attained a specific capacitance of 181 F/g at a scan rate of 5 mV/s. An energy density of 1.72 Wh/kg and power density of 27.14 W/kg has been achieved at 89 mA/g current density in 1 M Na2SO3 solution.

  13. Influence of Ag doping concentration on structural and optical properties of CdS thin film

    SciTech Connect

    Kumar, Pragati; Saxena, Nupur; Gupta, Vinay; Agarwal, Avinash

    2015-05-15

    This work shows the influence of Ag concentration on structural properties of pulsed laser deposited nanocrystalline CdS thin film. X-ray photoelectron spectroscopy (XPS) studies confirm the dopant concentration in CdS films and atomic concentration of elements. XPS studies show that the samples are slightly sulfur deficient. GAXRD scan reveals the structural phase transformation from cubic to hexagonal phase of CdS without appearance of any phase of CdO, Ag{sub 2}O or Ag{sub 2}S suggesting the substitutional doping of Ag ions. Photoluminescence studies illustrate that emission intensity increases with increase in dopant concentration upto 5% and then decreases for higher dopant concentration.

  14. Open Photoacoustic Cell Configuration Applied to the Thermal Characterization of Liquid CdS Nanocomposites

    NASA Astrophysics Data System (ADS)

    Faraji, Nastaran; Mahmood Mat Yunus, W.; Kharazmi, Alireza; Saion, Elias; Behzad, Kasra

    2014-01-01

    CdS nanofluids were prepared by the gamma-radiation method at different radiation doses. The samples were characterized by UV-Vis spectroscopy and transmission electron microscopy. The open cell photoacoustic technique was used to measure the thermal effusivity of the CdS nanocomposites. In this technique a He-Ne laser was used as the excitation source and was operated at 632.8 nm with an output power of 70 mW. The precision and accuracy of this technique were initially established by measuring the thermal effusivity of distilled water and ethylene glycol. The thermal-effusivity values of these two samples were found to be close to the values reported in the literature. The thermal effusivity of CdS nanofluids decreased from (0.453 to 0.268) with increased dosage of gamma radiation.

  15. Effect of pyridine as a ligand in precursor on morphology of CdS nanoparticles

    NASA Astrophysics Data System (ADS)

    Srinivasan, Narayanaswamy; Thirumaran, Subbiah

    2012-06-01

    [Cd(thqdtc)2], [Cd(thqdtc)2(py)] and [Cd(thqdtc)2(2,2'-bipy)] (where thqdtc = 1,2,3,4-tetrahydroquinolinecarbodithioate; py = pyridine; 2,2'-bipy = 2,2'-bipyridine) have been found to be effective single source precursors for the preparation of diethylenetriamine capped CdS nanoparticles via solvothermal method. Flower-like and rod-like CdS nanoparticles were prepared at a relatively low temperature by thermolysis of the precursors using chelating solvent diethylenetriamine. Use of [Cd(thqdtc)2] and [Cd(thqdtc)2(2,2'-bipy)] afforded rod-shaped nanoparticles and flower-like nanoparticles obtained from [Cd(thqdtc)2(py)]. UV-Visible spectroscopy established pronounced quantum confinement effect. X-ray diffraction (XRD) analysis revealed hexagonal crystal phase for so obtained CdS nanoparticles. The nanoparticles were also characterized by transmission electron microscopy (TEM) and fluorescence spectroscopy.

  16. Photoluminescence quenching and conductivity enhancement of PVK induced by CdS quantum dots

    NASA Astrophysics Data System (ADS)

    Masala, S.; Bizzarro, V.; Re, M.; Nenna, G.; Villani, F.; Minarini, C.; Di Luccio, T.

    2012-04-01

    In this work we studied the optical and transport properties of hybrid nanocomposites of CdS quantum dots (QDs) and poly(N-vinylcarbazole) (PVK) polymer. The CdS QDs were prepared by thermal decomposition (thermolysis) of a single source precursor, Cd bis-thiolate, in a high boiling solvent, octadecene (ODE). The optical characterization of the QDs has been carried out by UV-vis absorption and photoluminescence spectroscopy while the morphological properties have been investigated atomic force microscopy and transmission electron microscopy. The analyses have shown that CdS QDs of diameter below 6 nm can be synthesized by such route with good light emission in the UV range. The QDs have been dispersed in a poly(N-vinylcarbazole) (PVK) matrix to obtain a PVK:CdS nanocomposite layers. An increase of conductivity and a quenching of the photoluminescence have been observed when the nanocomposite layer was inserted in ITO/PVK:CdS/Al structures.

  17. Deposition and performance of CdS thin films on various substrates for photochemical cells

    NASA Astrophysics Data System (ADS)

    Bhardwaj, R. C.; Jadhav, C. M.; Taqui Khan, M. M.

    1984-09-01

    A photoelectrochemical study of CdS semiconductor electrodes with various metal substrates is presented. The current and voltage were measured by performing the experiments in a polysulphide electrolyte using a carbon counterelectrode. The electrodes were prepared by depositing a thin film of CdS by slurry painting, chemical-bath deposition, or electroplating in a non-aqueous solvent. The highest short-circuit current (0.9 mA) and open-circuit voltage (0.51 V) in a sun intensity of 70 mW/sq cm were obtained with slurry-painted electrodes after the films had been doped and etched. It appears that the efficiency of photochemical devices using polycrystal line CdS films can be improved to be comparable with that of single-crystal semiconductor material, with the advantages of low cost and simple technology.

  18. An electrochemical investigation of glucose oxidase at a CdS nanoparticles modified electrode.

    PubMed

    Huang, Yinxi; Zhang, Wenjun; Xiao, Han; Li, Genxi

    2005-11-15

    The direct electrochemistry of glucose oxidase (GOD) adsorbed on a CdS nanoparticles modified pyrolytic graphite electrode was investigated, where the enzyme demonstrated significantly enhanced electron-transfer reactivity. GOD adsorbed on CdS nanoparticles maintained its bioactivity and structure, and could electro-catalyze the reduction of dissolved oxygen, which resulted in a great increase of the reduction peak current. Upon the addition of glucose, the reduction peak current decreased, which could be used for glucose detection. Performance and characteristics of the fabricated glucose biosensor were assessed with respect to detection limit, sensitivity, storage stability and interference exclusion. The results showed that the fabricated biosensor was sensitive and stable in detecting glucose, indicating that CdS nanoparticle was a good candidate material for the immobilization of enzyme in glucose biosensor construction. PMID:16242622

  19. Biosynthesis of luminescent CdS quantum dots using plant hairy root culture

    NASA Astrophysics Data System (ADS)

    Borovaya, Mariya N.; Naumenko, Antonina P.; Matvieieva, Nadia A.; Blume, Yaroslav B.; Yemets, Alla I.

    2014-12-01

    CdS nanoparticles have a great potential for application in chemical research, bioscience and medicine. The aim of this study was to develop an efficient and environmentally-friendly method of plant-based biosynthesis of CdS quantum dots using hairy root culture of Linaria maroccana L. By incubating Linaria root extract with inorganic cadmium sulfate and sodium sulfide we synthesized stable luminescent CdS nanocrystals with absorption peaks for UV-visible spectrometry at 362 nm, 398 nm and 464 nm, and luminescent peaks at 425, 462, 500 nm. Transmission electron microscopy of produced quantum dots revealed their spherical shape with a size predominantly from 5 to 7 nm. Electron diffraction pattern confirmed the wurtzite crystalline structure of synthesized cadmium sulfide quantum dots. These results describe the first successful attempt of quantum dots synthesis using plant extract.

  20. CdS quantum dots: growth, microstructural, optical and electrical characteristics

    NASA Astrophysics Data System (ADS)

    Ahamad, Tansir; Majeed Khan, M. A.; Kumar, Sushil; Ahamed, Maqusood; Shahabuddin, Mohammed; Alhazaa, Abdulaziz N.

    2016-06-01

    Cadmium sulfide (CdS) quantum dots (QDs) with cubic phase were prepared using simple precursors by chemical precipitation technique, and their thin films were grown on glass substrates by chemical bath deposition. The obtained quantum dots were characterized for their structural, morphological, optical, thermal and electrical properties using X-ray diffraction (XRD), field emission transmission electron microscopy, UV-visible absorption spectroscopy, Raman spectroscopy, photoluminescence, thermogravimetric analysis/differential thermal analysis and low-temperature electrical transport measurements, respectively. XRD pattern reveals that the prepared CdS QDs are highly pure and crystalline in nature with cubic phase. The average particle size, estimated to be ~2 nm, is almost in agreement with the values calculated by Brusïs formula. Selected area electron diffraction also recognizes the cubic structure of CdS quantum dots. The UV-visible spectra exhibit a blueshift with respect to that of bulk sample which is attributed to the quantum size effect of electrons and holes. The band gap of CdS QDs is calculated from absorption data using Tauc plot and found to be 2.84 eV. Energy-dispersive X-ray analysis reveals the presence of Cd and S in almost stoichiometric ratio in the prepared CdS QDs. Micro-Raman spectroscopic studies also yield convincing evidence for the transformation of structure. The emission spectra of CdS QDs show peak centered at 541 nm, which is attributed to the presence of cadmium vacancies in the lattice. The DC resistivity data at low temperatures are qualitatively consistent with the variable-range hopping model, and the density of states at the Fermi level is determined.