Science.gov

Sample records for continuous conduction mode

  1. Modeling and dynamics analysis of the fractional-order Buck—Boost converter in continuous conduction mode

    NASA Astrophysics Data System (ADS)

    Yang, Ning-Ning; Liu, Chong-Xin; Wu, Chao-Jun

    2012-08-01

    In this paper, the fractional-order mathematical model and the fractional-order state-space averaging model of the Buck—Boost converter in continuous conduction mode (CCM) are established based on the fractional calculus and the Adomian decomposition method. Some dynamical properties of the current-mode controlled fractional-order Buck—Boost converter are analysed. The simulation is accomplished by using SIMULINK. Numerical simulations are presented to verify the analytical results and we find that bifurcation points will be moved backward as α and β vary. At the same time, the simulation results show that the converter goes through different routes to chaos.

  2. Continuous scanning mode for ptychography

    SciTech Connect

    Clark, Jesse N.; Huang, Xiaojing; Harder, Ross; Robinson, Ian K.

    2014-10-15

    We outline how ptychographic imaging can be performed without the need for discrete scan positions. Through an idealized experiment, we demonstrate how a discrete-position scan regime can be replaced with a continuously scanned one with suitable modification of the reconstruction scheme based on coherent modes. The impact of this is that acquisition times can be reduced, significantly aiding ptychographic imaging with x rays, electrons, or visible light.

  3. Continuous scanning mode for ptychography

    SciTech Connect

    Clark, Jesse N.; Huang, Xiaojing; Harder, Ross J.; Robinson, Ian K.

    2014-10-15

    We outline how ptychographic imaging can be performed without the need for discrete scan positions. Through an idealized experiment, we demonstrate how a discrete-position scan regime can be replaced with a continuously scanned one with suitable modification of the reconstruction scheme based on coherent modes. Thus, the impact of this is that acquisition times can be reduced, significantly aiding ptychographic imaging with x rays, electrons, or visible light.

  4. Continuous scanning mode for ptychography

    SciTech Connect

    Clark, Jesse N.; Huang, Xiaojing; Harder, Ross J.; Robinson, Ian K.

    2014-01-01

    Here, we outline how ptychographic imaging can be performed without the need for discrete scan positions. Through an idealized experiment, we demonstrate how a discrete-position scan regime can be replaced with a continuously scanned one with suitable modification of the reconstruction scheme based on coherent modes. Furthermore, the impact of this is that acquisition times can be reduced, significantly aiding ptychographic imaging with x rays, electrons, or visible light.

  5. Dark current studies on a normal-conducting high-brightness very-high-frequency electron gun operating in continuous wave mode

    NASA Astrophysics Data System (ADS)

    Huang, R.; Filippetto, D.; Papadopoulos, C. F.; Qian, H.; Sannibale, F.; Zolotorev, M.

    2015-01-01

    We report on measurements and analysis of a field-emitted electron current in the very-high-frequency (VHF) gun, a room temperature rf gun operating at high field and continuous wave (CW) mode at the Lawrence Berkeley National Laboratory (LBNL). The VHF gun is the core of the Advanced Photo-injector Experiment (APEX) at LBNL, geared toward the development of an injector for driving the next generation of high average power x-ray free electron lasers. High accelerating fields at the cathode are necessary for the high-brightness performance of an electron gun. When coupled with CW operation, such fields can generate a significant amount of field-emitted electrons that can be transported downstream the accelerator forming the so-called "dark current." Elevated levels of a dark current can cause radiation damage, increase the heat load in the downstream cryogenic systems, and ultimately limit the overall performance and reliability of the facility. We performed systematic measurements that allowed us to characterize the field emission from the VHF gun, determine the location of the main emitters, and define an effective strategy to reduce and control the level of dark current at APEX. Furthermore, the energy spectra of isolated sources have been measured. A simple model for energy data analysis was developed that allows one to extract information on the emitter from a single energy distribution measurement.

  6. Comparison of detectability in step-and-shoot mode and continuous mode digital tomosynthesis systems

    NASA Astrophysics Data System (ADS)

    Lee, Changwoo; Han, Minah; Baek, Jongduk

    2017-03-01

    Digital tomosynthesis system has been widely used in chest, dental, and breast imaging. Since the digital tomosynthesis system provides volumetric images from multiple projection data, structural noise inherent in X-ray radiograph can be reduced, and thus signal detection performance is improved. Currently, tomosynthesis system uses two data acquisition modes: step-and-shoot mode and continuous mode. Several studies have been conducted to compare the system performance of two acquisition modes with respect to spatial resolution and contrast. In this work, we focus on signal detectability in step-and-shoot mode and continuous mode. For evaluation, uniform background is considered, and eight spherical objects with diameters of 0.5, 0.8, 1, 2, 3, 5, 8, 10 mm are used as signals. Projection data with and without spherical objects are acquired in step-and-shoot mode and continuous mode, respectively, and quantum noise are added. Then, noisy projection data are reconstructed by FDK algorithm. To compare the detection performance of two acquisition modes, we calculate task signal-to-noise ratio (SNR) of channelized Hotelling observer with Laguerre-Gauss channels for each spherical object. While the task-SNR values of two acquisition modes are similar for spherical objects larger than 1 mm diameter, step-and-shoot mode yields higher detectability for small signal sizes. The main reason of this behavior is that small signal is more affected by X-ray tube motion blur than large signal. Our results indicate that it is beneficial to use step-and-shoot data acquisition mode to improve the detectability of small signals (i.e., less than 1 mm diameter) in digital tomosynthesis systems.

  7. Phase modulation mode of scanning ion conductance microscopy

    SciTech Connect

    Li, Peng; Zhang, Changlin; Liu, Lianqing E-mail: gli@engr.pitt.edu; Wang, Yuechao; Yang, Yang; Li, Guangyong E-mail: gli@engr.pitt.edu

    2014-08-04

    This Letter reports a phase modulation (PM) mode of scanning ion conductance microscopy. In this mode, an AC current is directly generated by an AC voltage between the electrodes. The portion of the AC current in phase with the AC voltage, which is the current through the resistance path, is modulated by the tip-sample distance. It can be used as the input of feedback control to drive the scanner in Z direction. The PM mode, taking the advantages of both DC mode and traditional AC mode, is less prone to electronic noise and DC drift but maintains high scanning speed. The effectiveness of the PM mode has been proven by experiments.

  8. GENERAL: Mode shift and stability control of a current mode controlled buck-boost converter operating in discontinuous conduction mode with ramp compensation

    NASA Astrophysics Data System (ADS)

    Bao, Bo-Cheng; Xu, Jian-Ping; Liu, Zhong

    2009-11-01

    By establishing the discrete iterative mapping model of a current mode controlled buck-boost converter, this paper studies the mechanism of mode shift and stability control of the buck-boost converter operating in discontinuous conduction mode with a ramp compensation current. With the bifurcation diagram, Lyapunov exponent spectrum, time-domain waveform and parameter space map, the performance of the buck-boost converter circuit utilizing a compensating ramp current has been analysed. The obtained results indicate that the system trajectory is weakly chaotic and strongly intermittent under discontinuous conduction mode. By using ramp compensation, the buck-boost converter can shift from discontinuous conduction mode to continuous conduction mode, and effectively operates in the stable period-one region.

  9. Totem-Pole Power-Factor-Correction Converter under Critical-Conduction-Mode Interleaved Operation

    NASA Astrophysics Data System (ADS)

    Firmansyah, Eka; Tomioka, Satoshi; Abe, Seiya; Shoyama, Masahito; Ninomiya, Tamotsu

    This paper proposes a new power-factor-correction (PFC) topology, and explains its operation principle, its control mechanism, related application problems followed by experimental results. In this proposed topology, critical-conduction-mode (CRM) interleaved technique is applied to a bridgeless PFC in order to achieve high efficiency by combining benefits of each topology. This application is targeted toward low to middle power applications that normally employs continuous-conduction-mode boost converter.

  10. Mode dependent lattice thermal conductivity of single layer graphene

    SciTech Connect

    Wei, Zhiyong; Yang, Juekuan; Bi, Kedong; Chen, Yunfei

    2014-10-21

    Molecular dynamics simulation is performed to extract the phonon dispersion and phonon lifetime of single layer graphene. The mode dependent thermal conductivity is calculated from the phonon kinetic theory. The predicted thermal conductivity at room temperature exhibits important quantum effects due to the high Debye temperature of graphene. But the quantum effects are reduced significantly when the simulated temperature is as high as 1000 K. Our calculations show that out-of-plane modes contribute about 41.1% to the total thermal conductivity at room temperature. The relative contribution of out-of-plane modes has a little decrease with the increase of temperature. Contact with substrate can reduce both the total thermal conductivity of graphene and the relative contribution of out-of-plane modes, in agreement with previous experiments and theories. Increasing the coupling strength between graphene and substrate can further reduce the relative contribution of out-of-plane modes. The present investigations also show that the relative contribution of different mode phonons is not sensitive to the grain size of graphene. The obtained phonon relaxation time provides useful insight for understanding the phonon mean free path and the size effects in graphene.

  11. Continuous mode interaction and the bypass route to transition

    NASA Astrophysics Data System (ADS)

    Zaki, Tamer A.

    Boundary layer transition to turbulence, without the intervention of Tollmien-Schlichting instability waves, is designated 'bypass transition'. That terminology is all-encompassing; many bypass mechanisms are possible, for example transition due to surface roughness, acoustic perturbations, or free-stream vortical disturbances. It is the last that has become synonymous with the term bypass, and is the focus of this work. The perspective that bypass is the complement to orderly transition suggests that it be studied by starting from the complement to Tollmien-Schlichting waves. The latter are the discrete modes of the Orr-Sommerfeld operator; their complement is the continuous spectrum. An examination of mode shapes sheds light on boundary layer receptivity to vortical disturbances: Low-frequency modes penetrate the boundary layer, while high frequencies are expelled---a result referred to as shear sheltering. Low frequency penetration can be characterized by a coupling coefficient. Large coupling, Orr-Sommerfeld modes resonantly force the Squire operator. The response is a superposition of Squire modes, and their incomplete cancellation gives rise to Klebanoff modes, which resemble jets in the perturbation field. While this is a route into the boundary layer, transition subsequently involves an inter-action between low and high frequency modes. The lifted, low-frequency perturbation jets are susceptible to a Kelvin-Helmholtz type instability that marks the onset of breakdown and turbulent spots. Continuous mode transition is illustrated by numerical simulations of pairwise mode interaction. Only two modes, one low-frequency penetrating and one high-frequency sheltered eigenfunction, can induce transition in a manner that emulates the influence of a spectrum of vortical disturbances. This new framework provides a link between the continuous eigenmodes from linear theory, and the non-linear interaction that causes transition to turbulence. The role of pressure

  12. Scaling solutions for connectivity and conductivity of continuous random networks.

    PubMed

    Galindo-Torres, S A; Molebatsi, T; Kong, X-Z; Scheuermann, A; Bringemeier, D; Li, L

    2015-10-01

    Connectivity and conductivity of two-dimensional fracture networks (FNs), as an important type of continuous random networks, are examined systematically through Monte Carlo simulations under a variety of conditions, including different power law distributions of the fracture lengths and domain sizes. The simulation results are analyzed using analogies of the percolation theory for discrete random networks. With a characteristic length scale and conductivity scale introduced, we show that the connectivity and conductivity of FNs can be well described by universal scaling solutions. These solutions shed light on previous observations of scale-dependent FN behavior and provide a powerful method for quantifying effective bulk properties of continuous random networks.

  13. CONTINUOUS CONDUCTION OF IMPULSES IN PERIPHERAL MYELINATED NERVE FIBERS

    PubMed Central

    Laporte, Y.

    1951-01-01

    1. Conduction of impulses in peripheral myelinated fibers of a nerve trunk is a continuous process, since with uninjured nerve fibers: (a) within each internodal segment the conduction time increases continuously and linearly with increasing conduction distance; (b) the presence of nodes of Ranvier does not result in any detectable discontinuity in the conduction of the impulse; (c) the ascending phase of the spike always has an S shape and never presents signs of fractionation; (d) the shape and magnitude of the spike are constant at all points of each internodal segment. 2. Records have been presented of the external logitudinal current that flows during propagation of an impulse in undissected single nerve fiber (Fig. 6). 3. Propagation of impulses across a conduction block occurs with a readily demonstrable discontinuity. PMID:14898021

  14. Tissue lesion created by HIFU in continuous scanning mode

    NASA Astrophysics Data System (ADS)

    Fan, Tingbo; Liu, Zhenbo; Zhang, Dong

    2012-09-01

    The lesion formation was numerically and experimentally investigated by the continuous scanning mode. Simulations were presented based on the combination of Khokhlov-Zabolotskaya-Kuznetov (KZK) equation and bio-heat equation. Measurements were performed on porcine liver tissues using a 1.01 MHz single-element focused transducer at various acoustic powers, confirmed the predicted results. Controlling of the peak temperature and lesion by the scanning speed may be exploited for improvement of efficiency in HIFU therapy.

  15. Continuous-mode operation of a noiseless linear amplifier

    NASA Astrophysics Data System (ADS)

    Li, Yi; Carvalho, André R. R.; James, Matthew R.

    2016-05-01

    We develop a dynamical model to describe the operation of the nondeterministic noiseless linear amplifier (NLA) in the regime of continuous-mode inputs. We analyze the dynamics conditioned on the detection of photons and show that the amplification gain depends on detection times and on the temporal profile of the input state and the auxiliary single-photon state required by the NLA. We also show that the output amplified state inherits the pulse shape of the ancilla photon.

  16. Continuous spectrum of modes for optical micro-sphere resonators

    NASA Astrophysics Data System (ADS)

    Nooramin, Amir Saman; Shahabadi, Mahmoud

    2016-09-01

    This paper presents an improved modal analysis for the spherical dielectric resonator. This is commonly carried out by assuming an outgoing spherical Hankel function for the region surrounding the dielectric sphere. It will be shown that this assumption is incomplete and cannot lead to the entire spectrum of resonance frequencies. Following an analytical formulation, we prove that, like cylindrical resonators, the only choice for the outer region of the dielectric sphere can be a proper linear combination of an inward and an outward traveling wave. Starting from this formulation, we determine the complete spectrum of the resonance frequencies and the associated mode fields. In this analysis, the continuous spectrum of resonance frequencies is introduced and the properties of radiation modes are studied in detail. The proposed analytical formulation is thereafter employed to calculate the quality factor of the resonator due to radiation and dielectric loss.

  17. Continuous-function ground conductivity model for the determination of electric railway earth conductance

    SciTech Connect

    Carpenter, D.C. ); Hill, R.J. . School of Electronic and Electrical Engineering)

    1993-09-01

    A method is described for the determination of ground conductivity as a continuous function of depth and frequency for applications along spatially linear structures such as railway tracks. The technique involves measurements of mutual resistance using a modified dipole array excited with AC currents up to audio frequency. After representation of the experimental data by analytic functions, the ground conductivity-depth variation is obtained as a degenerate hypergeometric function. The determined ground conductivity is utilized to model the self and mutual conductance of and between the running rails in a single-track railway. The result is verified by experimental measurement.

  18. Higher Order Mode Coupler Heating in Continuous Wave Operation

    NASA Astrophysics Data System (ADS)

    Solyak, N.; Awida, M.; Hocker, A.; Khabibobulline, T.; Lunin, A.

    Electromagnetic heating due to higher order modes (HOM) propagation is particularly a concern for continuous wave (CW) particle accelerator machines. Power on the order of several watts could flow out of the cavity's HOM ports in CW operations. The upgrade of the Linac Coherent Light Source (LCLS-II) at SLAC requires a major modification of the design of the higher order mode (HOM) antenna and feed through of the conventional ILC elliptical 9-cell cavity in order to utilize it for LCLS-II. The HOM antenna is required to bear higher RF losses, while relatively maintaining the coupling level of the higher order modes. In this paper, we present a detailed analysis of the heating expected in the HOM coupler with a thorough thermal quench study in comparison with the conventional ILC design. We discuss also how the heat will be removed from the cavity through RF cables with specially designed cooling straps. Finally, we report on the latest experimental results of cavity testing in vertical and horizontal cryostats.

  19. Investigation of continuously traversing microphone system for mode measurement

    NASA Technical Reports Server (NTRS)

    Cicon, D. E.; Sofrin, T. G.; Mathews, D. C.

    1982-01-01

    The continuously Traversing Microphone System consists of a data acquisition and processing method for obtaining the modal coefficients of the discrete, coherent acoustic field in a fan inlet duct. The system would be used in fan rigs or full scale engine installations where present measurement methods, because of the excessive number of microphones and long test times required, are not feasible. The purpose of the investigation reported here was to develop a method for defining modal structure by means of a continuously traversing microphone system and to perform an evaluation of the method, based upon analytical studies and computer simulated tests. A variety of system parameters were examined, and the effects of deviations from ideal were explored. Effects of traverse speed, digitizing rate, run time, roundoff error, calibration errors, and random noise background level were determined. For constant fan operating speed, the sensitivity of the method to normal errors and deviations was determined to be acceptable. Good recovery of mode coefficients was attainable. Fluctuating fan speed conditions received special attention, and it was concluded that by employing suitable time delay procedures, satisfactory information on mode coefficients can be obtained under realistic conditions. A plan for further development involving fan rig tests was prepared.

  20. Modeling and performance analysis of the fractional order quadratic Boost converter in discontinuous conduction mode-discontinuous conduction mode

    NASA Astrophysics Data System (ADS)

    Tan, Cheng; Liang, Zhi-Shan

    2016-03-01

    In this paper, based on the fact that the inductors and capacitors are of fractional order in nature, the four-order mathematical model of the fractional order quadratic Boost converter in type I and type II discontinuous conduction mode (DCM) — DCM is established by using fractional calculus theory. Direct current (DC) analysis is conducted by using the DC equivalent model and the transfer functions are derived from the corresponding alternating current (AC) equivalent model. The DCM-DCM regions of type I and type II are obtained and the relations between the regions and the orders are found. The influence of the orders on the performance of the quadratic Boost converter in DCM-DCM is verified by numerical and circuit simulations. Simulation results demonstrate the correctness of the fractional order model and the efficiency of the proposed theoretical analysis.

  1. Reduced Default Mode Connectivity in Adolescents With Conduct Disorder.

    PubMed

    Broulidakis, M John; Fairchild, Graeme; Sully, Kate; Blumensath, Thomas; Darekar, Angela; Sonuga-Barke, Edmund J S

    2016-09-01

    Conduct disorder (CD) is characterized by impulsive, aggressive, and antisocial behaviors that might be related to deficits in empathy and moral reasoning. The brain's default mode network (DMN) has been implicated in self-referential cognitive processes of this kind. This study examined connectivity between key nodes of the DMN in 29 adolescent boys with CD and 29 age- and sex-matched typically developing adolescent boys. The authors ensured that group differences in DMN connectivity were not explained by comorbidity with other disorders by systematically controlling for the effects of substance use disorders (SUDs), attention-deficit/hyperactivity disorder (ADHD) symptoms, psychopathic traits, and other common mental health problems. Only after adjusting for co-occurring ADHD symptoms, the group with CD showed hypoconnectivity between core DMN regions compared with typically developing controls. ADHD symptoms were associated with DMN hyperconnectivity. There was no effect of psychopathic traits on DMN connectivity in the group with CD, and the key results were unchanged when controlling for SUDs and other common mental health problems. Future research should directly investigate the possibility that the aberrant DMN connectivity observed in the present study contributes to CD-related deficits in empathy and moral reasoning and examine self-referential cognitive processes in CD more generally. Copyright © 2016 American Academy of Child and Adolescent Psychiatry. All rights reserved.

  2. New Edge Coherent Mode Providing Continuous Transport in Long-Pulse H-mode Plasmas

    NASA Astrophysics Data System (ADS)

    Wang, H. Q.; Xu, G. S.; Wan, B. N.; Ding, S. Y.; Guo, H. Y.; Shao, L. M.; Liu, S. C.; Xu, X. Q.; Wang, E.; Yan, N.; Naulin, V.; Nielsen, A. H.; Rasmussen, J. Juul; Candy, J.; Bravenec, R.; Sun, Y. W.; Shi, T. H.; Liang, Y. F.; Chen, R.; Zhang, W.; Wang, L.; Chen, L.; Zhao, N.; Li, Y. L.; Liu, Y. L.; Hu, G. H.; Gong, X. Z.

    2014-05-01

    An electrostatic coherent mode near the electron diamagnetic frequency (20-90 kHz) is observed in the steep-gradient pedestal region of long pulse H-mode plasmas in the Experimental Advanced Superconducting Tokamak, using a newly developed dual gas-puff-imaging system and diamond-coated reciprocating probes. The mode propagates in the electron diamagnetic direction in the plasma frame with poloidal wavelength of ˜8 cm. The mode drives a significant outflow of particles and heat as measured directly with the probes, thus greatly facilitating long pulse H-mode sustainment. This mode shows the nature of dissipative trapped electron mode, as evidenced by gyrokinetic turbulence simulations.

  3. Robust sliding mode continuous control of an IM drive

    SciTech Connect

    Jezernik, K.; Hren, A.; Drevensek, D.

    1995-12-31

    A control approach for robust trajectory tracking of IM servodrive based on the variable structure systems (VSS) is described. A new discrete-time control algorithm has been developed by combining VSS and Lyapunov design. It possesses all the good properties of the sliding mode and avoids the unnecessary discontinuity of the control input, thus eliminating chattering which has been considering as serious obstacles for applications of VSS. A unified control approach for current, torque and motion control based on the discrete-time sliding mode for application in indirect vector control of an IM drive is developed. The sliding mode approach can be applied to the control of an Im drive due to the replacement of the hysteresis controller with widely used PWM technique. All the theoretical issues are verified by experiment. The experimental system consists of a transputer and a microcontroller, thus allowing parallel processing.

  4. Frequency Management for Electromagnetic Continuous Wave Conductivity Meters

    PubMed Central

    Mazurek, Przemyslaw; Putynkowski, Grzegorz

    2016-01-01

    Ground conductivity meters use electromagnetic fields for the mapping of geological variations, like the determination of water amount, depending on ground layers, which is important for the state analysis of embankments. The VLF band is contaminated by numerous natural and artificial electromagnetic interference signals. Prior to the determination of ground conductivity, the meter’s working frequency is not possible, due to the variable frequency of the interferences. Frequency management based on the analysis of the selected band using track-before-detect (TBD) algorithms, which allows dynamical frequency changes of the conductivity of the meter transmitting part, is proposed in the paper. Naive maximum value search, spatio-temporal TBD (ST-TBD), Viterbi TBD and a new algorithm that uses combined ST-TBD and Viterbi TBD are compared. Monte Carlo tests are provided for the numerical analysis of the properties for a single interference signal in the considered band, and a new approach based on combined ST-TBD and Viterbi algorithms shows the best performance. The considered algorithms process spectrogram data for the selected band, so DFT (Discrete Fourier Transform) could be applied for the computation of the spectrogram. Real–time properties, related to the latency, are discussed also, and it is shown that TBD algorithms are feasible for real applications. PMID:27070608

  5. Frequency Management for Electromagnetic Continuous Wave Conductivity Meters.

    PubMed

    Mazurek, Przemyslaw; Putynkowski, Grzegorz

    2016-04-07

    Ground conductivity meters use electromagnetic fields for the mapping of geological variations, like the determination of water amount, depending on ground layers, which is important for the state analysis of embankments. The VLF band is contaminated by numerous natural and artificial electromagnetic interference signals. Prior to the determination of ground conductivity, the meter's working frequency is not possible, due to the variable frequency of the interferences. Frequency management based on the analysis of the selected band using track-before-detect (TBD) algorithms, which allows dynamical frequency changes of the conductivity of the meter transmitting part, is proposed in the paper. Naive maximum value search, spatio-temporal TBD (ST-TBD), Viterbi TBD and a new algorithm that uses combined ST-TBD and Viterbi TBD are compared. Monte Carlo tests are provided for the numerical analysis of the properties for a single interference signal in the considered band, and a new approach based on combined ST-TBD and Viterbi algorithms shows the best performance. The considered algorithms process spectrogram data for the selected band, so DFT (Discrete Fourier Transform) could be applied for the computation of the spectrogram. Real-time properties, related to the latency, are discussed also, and it is shown that TBD algorithms are feasible for real applications.

  6. Study of a harmonic mode lock stability under external continuous-wave injection

    NASA Astrophysics Data System (ADS)

    Semaan, Georges; Komarov, Andrey; Salhi, Mohamed; Sanchez, François

    2017-03-01

    In this paper, we investigate experimentally the effect of an injected continuous external optical laser in a stable passive harmonic mode-locked fiber laser operating in the anomalous dispersion regime. Under specific conditions, the continuous-wave significantly increases the stability of the harmonic mode-locked regime. This occurs for a discrete set of wavelengths and below a critical injected power.

  7. Infrared single-mode hollow conductive waveguides for stellar interferometry

    NASA Astrophysics Data System (ADS)

    Labeye, Pierre; Broquin, Jean-Emmanuel; Kern, Pierre; Noël, Patrice; Saguet, Pierre; Labadie, Lucas; Ruilier, Cyril; Kirshner, Volker

    2006-02-01

    This paper reports the design, realisation, and characterisation of singlemode hollow conductive waveguides for stellar interferometry. These waveguides are developed in the frame of technological developments for the ESA DARWIN mission, which aims at direct detection of exoplanets and biomarkers on them (proof of life) using nulling interferometry in the 6-20 μm spectral range. The use of singlemode waveguides is mandatory in order to meet DARWIN required performance by achieving a modal filtering better than 10 -6. While there is ongoing developments of infrared dielectric fibers or integrated waveguides, both using chalcogenide glasses or silver halide compounds, this paper presents the first realisation and characterisation of singlemode hollow conductive waveguides in the DARWIN spectral range, by means of standard microelectronic and wafer bonding technologies.

  8. Excitation of Continuous and Discrete Modes in Incompressible Boundary Layers

    NASA Technical Reports Server (NTRS)

    Ashpis, David E.; Reshotko, Eli

    1998-01-01

    This report documents the full details of the condensed journal article by Ashpis & Reshotko (JFM, 1990) entitled "The Vibrating Ribbon Problem Revisited." A revised formal solution of the vibrating ribbon problem of hydrodynamic stability is presented. The initial formulation of Gaster (JFM, 1965) is modified by application of the Briggs method and a careful treatment of the complex double Fourier transform inversions. Expressions are obtained in a natural way for the discrete spectrum as well as for the four branches of the continuous spectra. These correspond to discrete and branch-cut singularities in the complex wave-number plane. The solutions from the continuous spectra decay both upstream and downstream of the ribbon, with the decay in the upstream direction being much more rapid than that in the downstream direction. Comments and clarification of related prior work are made.

  9. Effects of Conductivity Asymmetry Between the Northern and Southern Latitudes on Toroidal and Poloidal Mode

    NASA Astrophysics Data System (ADS)

    Jang, J. J.; Choi, J.; Lee, D. H.

    2016-12-01

    When the ionosphere has significant differences between the northern and southern conductance, it is well known that quarter-wave modes may occur as standing shear Alfvén waves. Owing to the finite conductivity at the ionospheric boundary, quarter-wave modes tend to have strong damping and energy dissipation, which indicates that we should pay attention to time-dependent feature of such transient modes. We study how quarter-waves are excited in both of toroidal and poloidal modes by adopting a 3-D dipole wave model. Unlike the previous studies that mainly showed peak frequency of the wave, we investigate the effects of 1) dipolar geometry, 2) ratios of bandwidth and peak frequency, 3) differential feature of toroidal and poloidal modes, respectively. It is presented how quarter-wave modes depend on various conditions above by examining time histories of electric and magnetic fields in the MHD dipole model where a broad range of ionospheric conductivities is considered.

  10. Continuum modes in rotating plasmas: General equations and continuous spectra for large aspect ratio tokamaks

    SciTech Connect

    Lakhin, V. P.; Ilgisonis, V. I.

    2011-09-15

    A theory for localized low-frequency ideal magnetohydrodynamical (MHD) modes in axisymmetric toroidal systems is generalized to take into account both toroidal and poloidal equilibrium plasma flows. The general set of equations describing the coupling of shear Alfven and slow (sound) modes and defining the continuous spectrum of rotating plasmas in axisymmetric toroidal systems is derived. The equations are applied to study the continuous spectra in large aspect ratio tokamaks. The unstable continuous modes in the case of predominantly poloidal plasma rotation with the angular velocity exceeding the sound frequency are found. Their stabilization by the shear Alfven coupling effect is studied.

  11. Contrast agent stability: a continuous B-mode imaging approach.

    PubMed

    Sboros, V; Moran, C M; Pye, S D; McDicken, W N

    2001-10-01

    The stability of contrast agents in suspensions with various dissolved gas levels has not been reported in the literature. An in vitro investigation has been carried out that studied the combined effect of varying the acoustic pressure along with degassing the suspension environment. In this study, the contrast agents were introduced into suspensions with different oxygen concentration levels, and their relative performance was assessed in terms of decay rate of their backscatter echoes. The partial pressures of oxygen in those solutions ranged between 1.5 and 26 kPa. Two IV and one arterial contrast agents were used: Definity, Quantison, and Myomap. It was found that Quantison and Myomap released free bubbles at high acoustic pressure that also dissolved faster in degassed suspensions. The backscatter decay for Definity did not depend on the air content of the suspensions. The destruction of bubbles was dependent on acoustic pressure. Different backscatter performance was observed by different populations of bubbles of the last two agents. The physical quantity of "overall backscatter" (OB) was defined as the integral of the decay rate over time of the backscatter of the contrast suspensions, and improved significantly the understanding of the behaviour of the agents. A quantitative analysis of the backscatter properties of contrast agents using a continuous imaging approach was difficult to achieve. This is due to the fact that the backscatter in the field of view is representative of a bubble population affected by the ultrasound (US) field, but this bubble population is not representative of the contrast suspension in the whole tank. Single frame insonation is suggested to avoid the effects of decay due to the ultrasonic field, and to measure a tank-representative backscatter. The definition of OB was useful, however, in understanding the behaviour of the agents.

  12. Braking of tearing mode rotation by ferromagnetic conducting walls in tokamaks

    SciTech Connect

    Fitzpatrick, Richard

    2015-09-15

    An in-depth investigation of the braking of tearing mode rotation in tokamak plasmas via eddy currents induced in external ferromagnetic conducting structures is performed. In general, there is a “forbidden band” of tearing mode rotation frequencies that separates a branch of high-frequency solutions from a branch of low-frequency solutions. When a high-frequency solution crosses the upper boundary of the forbidden band, there is a bifurcation to a low-frequency solution, and vice versa. The bifurcation thresholds predicted by simple torque-balance theory (which takes into account the electromagnetic braking torque acting on the plasma, as well as the plasma viscous restoring torque, but neglects plasma inertia) are found to be essentially the same as those predicted by more complicated time-dependent mode braking theory (which takes inertia into account). Significant ferromagnetism causes otherwise electromagnetically thin conducting structures to become electromagnetically thick and also markedly decreases the critical tearing mode amplitude above which the mode “locks” to the conducting structures (i.e., the high-frequency to low-frequency bifurcation is triggered). On the other hand, if the ferromagnetism becomes too large, then the forbidden band of mode rotation frequencies is suppressed, and the mode frequency consequently varies smoothly and reversibly with the mode amplitude.

  13. Braking of tearing mode rotation by ferromagnetic conducting walls in tokamaks

    NASA Astrophysics Data System (ADS)

    Fitzpatrick, Richard

    2015-09-01

    An in-depth investigation of the braking of tearing mode rotation in tokamak plasmas via eddy currents induced in external ferromagnetic conducting structures is performed. In general, there is a "forbidden band" of tearing mode rotation frequencies that separates a branch of high-frequency solutions from a branch of low-frequency solutions. When a high-frequency solution crosses the upper boundary of the forbidden band, there is a bifurcation to a low-frequency solution, and vice versa. The bifurcation thresholds predicted by simple torque-balance theory (which takes into account the electromagnetic braking torque acting on the plasma, as well as the plasma viscous restoring torque, but neglects plasma inertia) are found to be essentially the same as those predicted by more complicated time-dependent mode braking theory (which takes inertia into account). Significant ferromagnetism causes otherwise electromagnetically thin conducting structures to become electromagnetically thick and also markedly decreases the critical tearing mode amplitude above which the mode "locks" to the conducting structures (i.e., the high-frequency to low-frequency bifurcation is triggered). On the other hand, if the ferromagnetism becomes too large, then the forbidden band of mode rotation frequencies is suppressed, and the mode frequency consequently varies smoothly and reversibly with the mode amplitude.

  14. Tunable continuous wave single-mode dye laser directly pumped by a diode laser

    NASA Astrophysics Data System (ADS)

    Stefanska, D.; Suski, M.; Furmann, B.

    2017-04-01

    In this work, a tunable continuous wave single-mode ring dye laser (a modified version of Coherent model CR 699-21), directly optically pumped by an economy-class diode laser, has been set up. The laser was operated on Coumarin 498, and its generation profile covered part of the green spectral region not easily accessible in single-mode operation. The performance of the laser in both broad-band and single-mode operation regimes was studied. It was proved that optical pumping by diode lasers allows one to obtain single-mode operation of dye lasers that is sufficiently stable for high-resolution spectroscopy applications.

  15. Derivation of continuous wave mode output power from burst mode measurements in high-intensity ultrasound applications.

    PubMed

    Haller, Julian; Wilkens, Volker

    2014-03-01

    Measurement of the acoustic output power of transducers in burst mode and derivation of the results to the continuous wave (CW) case reduces heating problems during power measurements with radiation force balances and absorbing targets at high power levels, but requires the knowledge of an "effective duty factor," DReff. In this work, an alternative method for determining DReff is presented that allows the determination at any input voltage amplitude as it can be calculated from the input voltage rf signal in burst mode. Thus with this method, it is not necessary to apply CW signals at all.

  16. Acoustic mode measurements in the inlet of a model turbofan using a continuously rotating rake

    NASA Astrophysics Data System (ADS)

    Heidelberg, Laurence J.; Hall, David G.

    1993-01-01

    Comprehensive measurements of the spinning acoustic mode structure in the inlet of the Advanced Ducted Propeller (ADP) have been completed. These measurements were taken using a unique and previously untried method which was first proposed by T.G. Sofrin. A continuously rotating microphone system was employed. The ADP model was designed and built by Pratt & Whitney and tested in the NASA Lewis 9- by 15-foot Anechoic Wind Tunnel. Three inlet configurations were tested with cut-on and cutoff stator vane sets. The cutoff stator was designed to suppress all modes at the blade passing frequency. Rotating rake measurements indicate that several extraneous circumferential modes were active. The mode orders suggest that their source was an interaction between the rotor and small interruptions in the casing tip treatment. The cut-on stator produced the expected circumferential modes plus higher levels of the unexpected modes seen with the cutoff stator.

  17. Acoustic Mode Measurements in the Inlet of a Model Turbofan Using a Continuously Rotating Rake

    NASA Technical Reports Server (NTRS)

    Heidelberg, Laurence J.; Hall, David G.

    1992-01-01

    Comprehensive measurements of the spinning acoustic mode structure in the inlet of the Advanced Ducted Propeller (ADP) have been completed. These measurements were taken using a unique and previously untried method which was first proposed by T.G. Sofrin. A continuously rotating microphone system was employed. The ADP model was designed and built by Pratt & Whitney and tested in the NASA Lewis 9- by 15-foot Anechoic Wind Tunnel. Three inlet configurations were tested with cut-on and cutoff stator vane sets. The cutoff stator was designed to suppress all modes at the blade passing frequency. Rotating rake measurements indicate that several extraneous circumferential modes were active. The mode orders suggest that their source was an interaction between the rotor and small interruptions in the casing tip treatment. The cut-on stator produced the expected circumferential modes plus higher levels of the unexpected modes seen with the cutoff stator.

  18. 20 CFR 416.990 - When and how often we will conduct a continuing disability review.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... SUPPLEMENTAL SECURITY INCOME FOR THE AGED, BLIND, AND DISABLED Determining Disability and Blindness Continuing Or Stopping Disability Or Blindness § 416.990 When and how often we will conduct a continuing... continue to meet the disability or blindness requirements of the law. Payment ends if the medical or other...

  19. 20 CFR 416.990 - When and how often we will conduct a continuing disability review.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... SUPPLEMENTAL SECURITY INCOME FOR THE AGED, BLIND, AND DISABLED Determining Disability and Blindness Continuing Or Stopping Disability Or Blindness § 416.990 When and how often we will conduct a continuing... continue to meet the disability or blindness requirements of the law. Payment ends if the medical or other...

  20. 20 CFR 416.990 - When and how often we will conduct a continuing disability review.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... SUPPLEMENTAL SECURITY INCOME FOR THE AGED, BLIND, AND DISABLED Determining Disability and Blindness Continuing Or Stopping Disability Or Blindness § 416.990 When and how often we will conduct a continuing... continue to meet the disability or blindness requirements of the law. Payment ends if the medical or other...

  1. 20 CFR 416.990 - When and how often we will conduct a continuing disability review.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... SUPPLEMENTAL SECURITY INCOME FOR THE AGED, BLIND, AND DISABLED Determining Disability and Blindness Continuing Or Stopping Disability Or Blindness § 416.990 When and how often we will conduct a continuing... continue to meet the disability or blindness requirements of the law. Payment ends if the medical or other...

  2. KINK AND SAUSAGE MODES IN NONUNIFORM MAGNETIC SLABS WITH CONTINUOUS TRANSVERSE DENSITY DISTRIBUTIONS

    SciTech Connect

    Yu, Hui; Li, Bo; Chen, Shao-Xia; Guo, Ming-Zhe

    2015-11-20

    We examine the influence of a continuous density structuring transverse to coronal slabs on the dispersive properties of fundamental standing kink and sausage modes supported therein. We derive generic dispersion relations (DRs) governing linear fast waves in pressureless straight slabs with general transverse density distributions, and focus on cases where the density inhomogeneity takes place in a layer of arbitrary width and in arbitrary form. The physical relevance of the solutions to the DRs is demonstrated by the corresponding time-dependent computations. For all profiles examined, the lowest order kink modes are trapped regardless of longitudinal wavenumber k. A continuous density distribution introduces a difference to their periods of ≲13% when k is the observed range relative to the case where the density profile takes a step function form. Sausage modes and other branches of kink modes are leaky at small k, and their periods and damping times are heavily influenced by how the transverse density profile is prescribed, in particular the length scale. These modes have sufficiently high quality to be observable only for physical parameters representative of flare loops. We conclude that while the simpler DR pertinent to a step function profile can be used for the lowest order kink modes, the detailed information on the transverse density structuring needs to be incorporated into studies of sausage modes and higher order kink modes.

  3. Kink and Sausage Modes in Nonuniform Magnetic Slabs with Continuous Transverse Density Distributions

    NASA Astrophysics Data System (ADS)

    Yu, Hui; Li, Bo; Chen, Shao-Xia; Guo, Ming-Zhe

    2015-11-01

    We examine the influence of a continuous density structuring transverse to coronal slabs on the dispersive properties of fundamental standing kink and sausage modes supported therein. We derive generic dispersion relations (DRs) governing linear fast waves in pressureless straight slabs with general transverse density distributions, and focus on cases where the density inhomogeneity takes place in a layer of arbitrary width and in arbitrary form. The physical relevance of the solutions to the DRs is demonstrated by the corresponding time-dependent computations. For all profiles examined, the lowest order kink modes are trapped regardless of longitudinal wavenumber k. A continuous density distribution introduces a difference to their periods of ≲13% when k is the observed range relative to the case where the density profile takes a step function form. Sausage modes and other branches of kink modes are leaky at small k, and their periods and damping times are heavily influenced by how the transverse density profile is prescribed, in particular the length scale. These modes have sufficiently high quality to be observable only for physical parameters representative of flare loops. We conclude that while the simpler DR pertinent to a step function profile can be used for the lowest order kink modes, the detailed information on the transverse density structuring needs to be incorporated into studies of sausage modes and higher order kink modes.

  4. A device for conducting a dynamic modes of UIAB therapy with automatic process testing

    NASA Astrophysics Data System (ADS)

    Barylo, Hryhoriy I.; Hotra, Zenon Yu.; Kozhukhar, Oleksandr T.; Ivakh, Mariya S.; Surtel, Wojciech; Maciejewski, Marcin

    2016-09-01

    The structure and circuit of the implemented device is using an environmentally friendly radiation sources and pulse photo stimulus modes with frequencies that correspond frequencies processes in BL to create bio resonance effects to accelerate the procedures. Proposed one of the possible hardware solutions are based on usage of dynamic irradiation modes and automatic continuous optical testing procedures UIAB and PP. The changes of the optical characteristics of BL provides the doctor continuous information on the effectiveness of the procedure on the patient's condition.

  5. Molar conductivity calculation of Li-ion battery electrolyte based on mode coupling theory

    NASA Astrophysics Data System (ADS)

    Pu, Weihua; He, Xiangming; Lu, Jiufang; Jiang, Changyin; Wan, Chunrong

    2005-12-01

    A method is proposed to calculate molar conductivity based on mode coupling theory in which the ion transference number is introduced into the theory. The molar conductivities of LiPF6, LiClO4, LiBF4, LiAsF6 in PC (propylene carbonate) are calculated based on this method. The results fit well to the literature data. This presents a potential way to calculate the conductivities of Li-ion battery electrolytes.

  6. Molar conductivity calculation of Li-ion battery electrolyte based on mode coupling theory.

    PubMed

    Pu, Weihua; He, Xiangming; Lu, Jiufang; Jiang, Changyin; Wan, Chunrong

    2005-12-15

    A method is proposed to calculate molar conductivity based on mode coupling theory in which the ion transference number is introduced into the theory. The molar conductivities of LiPF6, LiClO4, LiBF4, LiAsF6 in PC (propylene carbonate) are calculated based on this method. The results fit well to the literature data. This presents a potential way to calculate the conductivities of Li-ion battery electrolytes.

  7. Multi-Mode Excitation and Data Reduction for Fatigue Crack Characterization in Conducting Plates

    NASA Technical Reports Server (NTRS)

    Wincheski, B.; Namkung, M.; Fulton, J. P.; Clendenin, C. G.

    1992-01-01

    Advances in the technique of fatigue crack characterization by resonant modal analysis have been achieved through a new excitation mechanism and data reduction of multiple resonance modes. A non-contacting electromagnetic device is used to apply a time varying Lorentz force to thin conducting sheets. The frequency and direction of the Lorentz force are such that resonance modes are generated in the test sample. By comparing the change in frequency between distinct resonant modes of a sample, detecting and sizing of fatigue cracks are achieved and frequency shifts caused by boundary condition changes can be discriminated against. Finite element modeling has been performed to verify experimental results.

  8. Ossicular resonance modes of the human middle ear for bone and air conduction

    PubMed Central

    Homma, Kenji; Du, Yu; Shimizu, Yoshitaka; Puria, Sunil

    2009-01-01

    The mean resonance frequency of the human middle ear under air conduction (AC) excitation is known to be around 0.8–1.2 kHz. However, studies suggest that the mean resonance frequency under bone conduction (BC) excitation is at a higher frequency around 1.5–2 kHz. To identify the cause for this difference, middle-ear responses to both AC and BC excitations were measured at the umbo and lateral process of the malleus using five human cadaver temporal bones. The resonance modes identified from these measurements, along with finite element analysis results, indicate the presence of two ossicular modes below 2 kHz. The dominant mode under AC excitation is the first mode, which typically occurs around 1.2 kHz and is characterized by a “hinging” ossicular motion, whereas the dominant mode under BC excitation is the second mode, which typically occurs around 1.7 kHz and is characterized by a “pivoting” ossicular motion. The results indicate that this second mode is responsible for the translational component in the malleus handle motion. The finding is also consistent with the hypothesis that a middle-ear structural resonance is responsible for the prominent peak seen at 1.5–2 kHz in BC limit data. PMID:19206873

  9. Monolithic dual-mode distributed feedback semiconductor laser for tunable continuous-wave terahertz generation.

    PubMed

    Kim, Namje; Shin, Jaeheon; Sim, Eundeok; Lee, Chul Wook; Yee, Dae-Su; Jeon, Min Yong; Jang, Yudong; Park, Kyung Hyun

    2009-08-03

    We report on a monolithic dual-mode semiconductor laser operating in the 1550-nm range as a compact optical beat source for tunable continuous-wave (CW) terahertz (THz) generation. It consists of two distributed feedback (DFB) laser sections and one phase section between them. Each wavelength of the two modes can be independently tuned by adjusting currents in micro-heaters which are fabricated on the top of the each DFB section. The continuous tuning of the CW THz emission from Fe(+)-implanted InGaAs photomixers is successfully demonstrated using our dual-mode laser as the excitation source. The CW THz frequency is continuously tuned from 0.17 to 0.49 THz.

  10. A general unified approach to modelling switching dc-to-dc converters in discontinuous conduction mode

    NASA Technical Reports Server (NTRS)

    Cuk, S.; Middlebrook, R. D.

    1977-01-01

    A method for modelling switching converters in the discontinuous conduction mode is developed, whose starting point is the unified state-space representation, and whose end result is a complete linear circuit model which correctly represents all essential features, namely, the input, output, and transfer properties (static dc as well as dynamic ac small signal). While the method is generally applicable to any switching converter operating in the discontinuous conduction mode, it is extensively illustrated for the three common power stages (buck, boost, and buck-boost). The results for these converters are then easily tabulated owing to the fixed equivalent circuit topology of their canonical circuit model.

  11. Lattice vibrational modes and phonon thermal conductivity of monolayer MoS2

    NASA Astrophysics Data System (ADS)

    Cai, Yongqing; Lan, Jinghua; Zhang, Gang; Zhang, Yong-Wei

    2014-01-01

    The anharmonic behavior of phonons and intrinsic thermal conductivity associated with the umklapp scattering in monolayer MoS2 sheet are investigated via first-principles calculations within the framework of density functional perturbation theory. In contrast to the negative Grüneissen parameter (γ) occurring in low-frequency modes in graphene, positive γ in the whole Brillouin zone is demonstrated in monolayer MoS2 with much larger γ for acoustic modes than that for the optical modes, suggesting that monolayer MoS2 sheet possesses a positive coefficient of thermal expansion. The calculated phonon lifetimes of the infrared active modes are 5.50 and 5.72 ps for E' and A2'', respectively, in good agreement with experimental results obtained by fitting the dielectric oscillators with the infrared reflectivity spectrum. The lifetime of the Raman A1' mode (38.36 ps) is about seven times longer than those of the infrared modes. The dominated phonon mean free path of monolayer MoS2 is less than 20 nm, about 30-fold smaller than that of graphene. Combined with the nonequilibrium Green's function calculations, the room temperature thermal conductivity of monolayer MoS2 is found to be around 23.2 W m-1 K-1, two orders of magnitude lower than that of graphene.

  12. Braking of Tearing Mode Rotation by Ferromagnetic Conducting Walls in Tokamaks

    NASA Astrophysics Data System (ADS)

    Fitzpatrick, Richard

    2015-11-01

    An in-depth investigation of the braking of tearing mode rotation in tokamak plasmas via eddy currents induced in external ferromagnetic conducting structures is performed. In general, there is a ``forbidden band'' of tearing mode rotation frequencies that separates a branch of high-frequency solutions from a branch of low-frequency solutions. When a high-frequency solution crosses the upper boundary of the forbidden band there is a bifurcation to a low-frequency solution, and vice versa. The bifurcation thresholds predicted by simple torque-balance theory (which takes into account the electromagnetic braking torque acting on the plasma, as well as the plasma viscous restoring torque, but neglects plasma inertia) are found to be essentially the same as those predicted by more complicated time-dependent mode braking theory (which takes inertia into account). Significant ferromagnetism causes otherwise electromagnetically thin conducting structures to become electromagnetically thick, and also markedly decreases the critical tearing mode amplitude above which the mode ``locks'' to the conducting structures (i.e., the high-frequency to low-frequency bifurcation is triggered). This research was funded by the U.S. Department of Energy under contract DE-FG02-04ER-54742.

  13. Phonon Heat Conduction In Nanostructures: Ballistic, Coherent, Localized, Hydrodynamic, and Divergent Modes

    NASA Astrophysics Data System (ADS)

    Chen, Gang

    In this talk, we will discuss different modes of heat conduction in nanostructures. Ballistic transport happens when phonon mean free path is longer than the characteristic size of the structure. We will discuss how we compute phonon mean free path distributions based on first-principles and measure the distributions with optical pump-probe techniques by exploring ballistic phonon transport processes. In superlattice structures, ballistic phonon transport across the whole thickness of the superlattices implies phase coherence. We observed this coherent transport in GaAs/AlAs superlattices with fixed periodic thickness and varying number of periods. Simulations show that although high frequency phonons are scattering by roughness, remaining long wavelength phonons maintain their phase and traverse the superlattices ballistically. Accessing the coherent heat conduction regime opens a new venue for phonon engineering. We show further that phonon heat conduction localization happens in GaAs/AlAs superlattice by placing ErAs nanodots at interfaces. This heat-conduction localization phenomenon is confirmed by nonequilibrium atomic Green's function simulation. These ballistic and localization effects can be exploited to improve thermoelectric energy conversion materials via reducing their thermal conductivity. In another opposite, we will discuss phonon hydrodynamic transport mode in graphene via first-principle simulations. In this mode, phonons drift with an average velocity under a temperature gradient, similar to fluid flow in a pipe. Conditions for observing such phonon hydrodynamic modes will be discussed. Finally, we will talk about the one-dimensional nature of heat conduction in polymer chains. Such 1D nature can lead to divergent thermal conductivity. Inspired by simulation, we have experimentally demonstrated high thermal conductivity in ultra-drawn polyethylene nanofibers and sheets. Work supported by DOE Office of Basic Energy Sciences under Award Number: DE

  14. New quantum dialogue protocol based on continuous-variable two-mode squeezed vacuum states

    NASA Astrophysics Data System (ADS)

    Zhou, Nan-Run; Li, Jian-Fu; Yu, Zhen-Bo; Gong, Li-Hua; Farouk, Ahmed

    2017-01-01

    A new quantum dialogue protocol is designed by using the continuous-variable two-mode squeezed vacuum states due to its entanglement property. The two communication parties encode their own secret information into the entangled optical modes with the translation operations. Each communication party could deduce the secret information of their counterparts with the help of his or her secret information and the Bell-basis measurement results. The security of the proposed quantum dialogue protocol is guaranteed by the correlation between two-mode squeezed vacuum states and the decoy states performed with translation operations in randomly selected time slots. Compared with the discrete variable quantum dialogue protocols, the proposed continuous-variable quantum dialogue protocol is easy to realize with perfect utilization of quantum bits.

  15. Resonantly pumped continuous-wave mode-locked Ho:YAP laser

    NASA Astrophysics Data System (ADS)

    Duan, X. M.; Lin, W. M.; Cui, Z.; Yao, B. Q.; Li, H.; Dai, T. Y.

    2016-04-01

    In this paper, we report a continuous-wave mode-locked Ho:YAP laser for the first time to our knowledge. Mode-locked pulse was produced by using an acousto-optic modulator. A 1.91-μm Tm-fiber laser as the pump source, at incident pump power of 25.9 W, the maximum output power of 2.87 W at 2117.8 nm was achieved in continuous-wave mode-locked regime. Pulse as short as 254.8 ps was obtained at repetition frequency of 81.52 MHz. In addition, the beam quality factor M 2 value of 1.6 was obtained.

  16. Effects Of Three-Dimensional Conducting Structures On Resistive Wall Modes

    SciTech Connect

    Villone, Fabio

    2008-11-01

    This paper illustrates the effect of three-dimensional conducting structures on the evolution of Resistive Wall Modes (RWM) occurring in toroidal fusion devices. The CarMa code is used to derive the model, which then is used to design a feedback controller of RWMs. Some examples of application to the ITER geometry are reported.

  17. Wigner spectrum and coherent feedback control of continuous-mode single-photon Fock states

    NASA Astrophysics Data System (ADS)

    Dong, Zhiyuan; Cui, Lei; Zhang, Guofeng; Fu, Hongchen

    2016-10-01

    Single photons are very useful resources in quantum information science. In real applications it is often required that the photons have a well-defined spectral (or equivalently temporal) modal structure. For example, a rising exponential pulse is able to fully excite a two-level atom while a Gaussian pulse cannot. This motivates the study of continuous-mode single-photon Fock states. Such states are characterized by a spectral (or temporal) pulse shape. In this paper we investigate the statistical property of continuous-mode single-photon Fock states. Instead of the commonly used normal ordering (Wick order), the tool we proposed is the Wigner spectrum. The Wigner spectrum has two advantages: (1) it allows to study continuous-mode single-photon Fock states in the time domain and frequency domain simultaneously; (2) because it can deal with the Dirac delta function directly, it has the potential to provide more information than the normal ordering where the Dirac delta function is always discarded. We also show how various control methods in particular coherent feedback control can be used to manipulate the pulse shapes of continuous-mode single-photon Fock states.

  18. Modes of Continuing Professional Education: A Test of Houle's Typology with Business Education Instructors.

    ERIC Educational Resources Information Center

    Powlette, Nina M.; Young, Darius R.

    1989-01-01

    The accuracy of Houle's typology in providing an accurate conceptual description of systematic structural forms of continuing professional education and business education instructors was tested via a survey of 98 (of 129) business educators. Results of rotation factor analysis added inquiry/reinforcement to Houle's 3 learning modes of…

  19. Mode shape reconstruction of an impulse excited structure using continuous scanning laser Doppler vibrometer and empirical mode decomposition.

    PubMed

    Kyong, Yongsoo; Kim, Daesung; Dayou, Jedol; Park, Kyihwan; Wang, Semyung

    2008-07-01

    For vibration testing, discrete types of scanning laser Doppler vibrometer (SLDV) have been developed and have proven to be very useful. For complex structures, however, SLDV takes considerable time to scan the surface of structures and require large amounts of data storage. To overcome these problems, a continuous scan was introduced as an alternative. In this continuous method, the Chebyshev demodulation (or polynomial) technique and the Hilbert transform approach have been used for mode shape reconstruction with harmonic excitation. As an alternative, in this paper, the Hilbert-Huang transform approach is applied to impact excitation cases in terms of a numerical approach, where the vibration of the tested structure is modeled using impulse response functions. In order to verify this technique, a clamped-clamped beam was chosen as the test rig in the numerical simulation and real experiment. This paper shows that with additional innovative steps of using ideal bandpass filters and nodal point determination in the postprocessing, the Hilbert-Huang transformation can be used to create a better mode shape reconstruction even in the impact excitation case.

  20. Observation of tearing mode deceleration and locking due to eddy currents induced in a conducting shell

    NASA Astrophysics Data System (ADS)

    Chapman, B. E.; Fitzpatrick, R.; Craig, D.; Martin, P.; Spizzo, G.

    2004-05-01

    Growth to large amplitude of a single core-resonant tearing mode in the Madison Symmetric Torus [R. N. Dexter et al., Fusion Technol. 19, 131 (1991)] reversed-field pinch is accompanied by braking and eventual cessation of mode rotation. There is also a concurrent deceleration of bulk plasma rotation. The mode deceleration is shown to be well described by a time-dependent version of a magnetohydrodynamical model [R. Fitzpatrick et al., Phys. Plasmas 6, 3878 (1999)] in which a braking torque originates from eddy currents induced by the rotating mode in the conducting shell surrounding the plasma. According to the model, the electromagnetic braking torque is localized to the plasma in the immediate vicinity of the mode's resonant surface, but viscosity transfers the torque to the rest of the plasma. Parametrizing the plasma viscous momentum diffusivity in terms of the global momentum confinement time, the model is used to predict both the momentum confinement time and the time evolution of the decelerating mode velocity. In both respects, the model is quite consistent with experimental data.

  1. Non-negligible Contributions to Thermal Conductivity From Localized Modes in Amorphous Silicon Dioxide

    NASA Astrophysics Data System (ADS)

    Lv, Wei; Henry, Asegun

    2016-10-01

    Thermal conductivity is important for almost all applications involving heat transfer. The theory and modeling of crystalline materials is in some sense a solved problem, where one can now calculate their thermal conductivity from first principles using expressions based on the phonon gas model (PGM). However, modeling of amorphous materials still has many open questions, because the PGM itself becomes questionable when one cannot rigorously define the phonon velocities. In this report, we used our recently developed Green-Kubo modal analysis (GKMA) method to study amorphous silicon dioxide (a-SiO2). The predicted thermal conductivities exhibit excellent agreement with experiments and anharmonic effects are included in the thermal conductivity calculation for all the modes in a-SiO2 for the first time. Previously, localized modes (locons) have been thought to have a negligible contribution to thermal conductivity, due to their highly localized nature. However, in a-SiO2 our results indicate that locons contribute more than 10% to the total thermal conductivity from 400 K to 800 K and they are largely responsible for the increase in thermal conductivity of a-SiO2 above room temperature. This is an effect that cannot be explained by previous methods and therefore offers new insight into the nature of phonon transport in amorphous/glassy materials.

  2. Non-negligible Contributions to Thermal Conductivity From Localized Modes in Amorphous Silicon Dioxide.

    PubMed

    Lv, Wei; Henry, Asegun

    2016-10-21

    Thermal conductivity is important for almost all applications involving heat transfer. The theory and modeling of crystalline materials is in some sense a solved problem, where one can now calculate their thermal conductivity from first principles using expressions based on the phonon gas model (PGM). However, modeling of amorphous materials still has many open questions, because the PGM itself becomes questionable when one cannot rigorously define the phonon velocities. In this report, we used our recently developed Green-Kubo modal analysis (GKMA) method to study amorphous silicon dioxide (a-SiO2). The predicted thermal conductivities exhibit excellent agreement with experiments and anharmonic effects are included in the thermal conductivity calculation for all the modes in a-SiO2 for the first time. Previously, localized modes (locons) have been thought to have a negligible contribution to thermal conductivity, due to their highly localized nature. However, in a-SiO2 our results indicate that locons contribute more than 10% to the total thermal conductivity from 400 K to 800 K and they are largely responsible for the increase in thermal conductivity of a-SiO2 above room temperature. This is an effect that cannot be explained by previous methods and therefore offers new insight into the nature of phonon transport in amorphous/glassy materials.

  3. Non-negligible Contributions to Thermal Conductivity From Localized Modes in Amorphous Silicon Dioxide

    PubMed Central

    Lv, Wei; Henry, Asegun

    2016-01-01

    Thermal conductivity is important for almost all applications involving heat transfer. The theory and modeling of crystalline materials is in some sense a solved problem, where one can now calculate their thermal conductivity from first principles using expressions based on the phonon gas model (PGM). However, modeling of amorphous materials still has many open questions, because the PGM itself becomes questionable when one cannot rigorously define the phonon velocities. In this report, we used our recently developed Green-Kubo modal analysis (GKMA) method to study amorphous silicon dioxide (a-SiO2). The predicted thermal conductivities exhibit excellent agreement with experiments and anharmonic effects are included in the thermal conductivity calculation for all the modes in a-SiO2 for the first time. Previously, localized modes (locons) have been thought to have a negligible contribution to thermal conductivity, due to their highly localized nature. However, in a-SiO2 our results indicate that locons contribute more than 10% to the total thermal conductivity from 400 K to 800 K and they are largely responsible for the increase in thermal conductivity of a-SiO2 above room temperature. This is an effect that cannot be explained by previous methods and therefore offers new insight into the nature of phonon transport in amorphous/glassy materials. PMID:27767082

  4. Continuous variables quantum computation over the vibrational modes of a single trapped ion

    NASA Astrophysics Data System (ADS)

    Ortiz-Gutiérrez, Luis; Gabrielly, Bruna; Muñoz, Luis F.; Pereira, Kainã T.; Filgueiras, Jefferson G.; Villar, Alessandro S.

    2017-08-01

    We consider the quantum processor based on a chain of trapped ions to propose an architecture wherein the motional degrees of freedom of trapped ions (position and momentum) could be exploited as the computational Hilbert space. We adopt a continuous-variables approach to develop a toolbox of quantum operations to manipulate one or two vibrational modes at a time. Together with the intrinsic non-linearity of the qubit degree of freedom, employed to mediate the interaction between modes, arbitrary manipulation and readout of the ionic wave function could be achieved.

  5. An effective method for designing insensitive resonator of continuous-wave passively mode-locked laser.

    PubMed

    Wen, Qiao; Sun, Liqun; Wang, Yonggang; Zhang, Enyao; Tian, Qian

    2009-05-25

    An effective method for designing the insensitive resonator of a continuous-wave passively mode-locked laser is firstly presented in this paper. This method, using resonator transform circle graphic theory, is both intuitive and reliable. Theoretical results show that the resonator is suitable to obtain highly stable mode locking operation when the following two conditions are fulfilled. First, the transform circle of the terminal mirror opposite the semiconductor saturable absorber mirror (SESAM) propagates through a series of lens (including the thermal lens of the gain medium) and a small transform circle in the image space is obtained, which ensures the small spot size at the SESAM. Second, the resonator transform circles orthogonally (or nearly orthogonally) intersect at the SESAM, which ensures the spot size at the SESAM is insensitive to the external perturbation. The experimental results of the mode locking lasers show good agreement with the theoretical studies very well.

  6. A new scanning mode to improve scanning ion conductance microscopy imaging rate with pipette predicted movement.

    PubMed

    Zhuang, Jian; Jiao, Yangbohan; Mugabo, Vincent

    2017-10-01

    Scanning ion conductance microscopy (SICM) is a non-contact surface topography measurement technique that has been increasingly used for soft surfaces such as living biological samples. An approach-retract scanning (ARS) mode is widely used to avoid collision between the SICM probe (i.e., pipette) and an abrupt increase in sample profile. However, the redundant pipette trajectory in the ARS mode lengthens the scan time, thus reducing SICM efficiency and time resolution. To avoid this problem, a new scanning mode is discussed that adds horizontal movement at each measurement point to predict the upcoming sample topography via variation in ion current. The pipette then retracts in response to raised topography, while it raster scans flat or downhill topography. The feasibility was verified by finite element analysis and experimental tests on three kinds of soft samples: polydimethylsiloxane, mice cardiac fibroblasts, and breast cancer cells. The pixel detection frequency during imaging and the mean square error of the sample topography were compared for the two modes. The new scanning mode enhances the SICM imaging rate without loss of imaging quality or scanning stability, while it increases efficiency and time resolution. It thus has an improved performance for characterizing biological samples. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Synthesis of Continuous Conductive PEDOT:PSS Nanofibers by Electrospinning: A Conformal Coating for Optoelectronics.

    PubMed

    Bessaire, Bastien; Mathieu, Maillard; Salles, Vincent; Yeghoyan, Taguhi; Celle, Caroline; Simonato, Jean-Pierre; Brioude, Arnaud

    2017-01-11

    A process to synthesize continuous conducting nanofibers were developed using PEDOT:PSS as a conducting polymer and an electrospinning method. Experimental parameters were carefully explored to achieve reproducible conductive nanofibers synthesis in large quantities. In particular, relative humidity during the electrospinning process was proven to be of critical importance, as well as doping post-treatment involving glycols and alcohols. The synthesized fibers were assembled as a mat on glass substrates, forming a conductive and transparent electrode and their optoelectronic have been fully characterized. This method produces a conformable conductive and transparent coating that is well-adapted to nonplanar surfaces, having very large aspect ratio features. A demonstration of this property was made using surfaces having deep trenches and high steps, where conventional transparent conductive materials fail because of a lack of conformability.

  8. A fast technique applied to the analysis of Resistive Wall Modes with 3D conducting structures

    SciTech Connect

    Rubinacci, Guglielmo Liu, Yueqiang

    2009-03-20

    This paper illustrates the development of a 'fast' technique for the analysis of Resistive Wall Modes (RWMs) in fusion devices with three-dimensional conducting structures, by means of the recently developed CarMa code. Thanks to its peculiar features, the computational cost scales almost linearly with the number of discrete unknowns. Some large scale problems are solved in configurations of interest for the International Thermonuclear Experimental Reactor (ITER)

  9. Fast Sausage Modes in Magnetic Tubes with Continuous Transverse Profiles: Effects of a Finite Plasma Beta

    NASA Astrophysics Data System (ADS)

    Chen, Shao-Xia; Li, Bo; Xiong, Ming; Yu, Hui; Guo, Ming-Zhe

    2016-12-01

    While standing fast sausage modes in flare loops are often invoked to interpret quasi-periodic pulsations (QPPs) in solar flares, it is unclear as to how they are influenced by the combined effects of a continuous transverse structuring and a finite internal plasma beta ({β }{{i}}). We derive a generic dispersion relation governing linear sausage waves in straight magnetic tubes for which plasma pressure is not negligible, and the density and temperature inhomogeneities of essentially arbitrary form take place in a layer of arbitrary width. Focusing on fast modes, we find that {β }{{i}} only weakly influences {k}{{c}}, the critical longitudinal wavenumber separating the leaky from trapped modes. Likewise, for both trapped and leaky modes, the periods P in units of the transverse fast time depend only weakly on {β }{{i}}, which is compatible with the fact that the effective wave vectors of fast sausage modes are largely perpendicular to the background magnetic field. However, a weak {β }{{i}} dependence of the damping times τ is seen only when the length-to-radius ratio L/R is ∼50% larger than some critical value π /({k}{{c}}R), which itself rather sensitively depends on the density contrast, profile steepness, as well as on how the transverse structuring is described. In the context of QPPs, we conclude that the much simpler zero-beta theory can be employed for trapped modes, as long as one sees the deduced internal Alfvén speed as actually being the fast speed. In contrast, effects due to a finite beta in flare loops should be considered when leaky modes are exploited.

  10. Different photodynamic effect between continuous wave and pulsed laser irradiation modes in k562 cells in vitro

    NASA Astrophysics Data System (ADS)

    Klimenko, V. V.; Bogdanov, A. A.; Knyazev, N. A.; Rusanov, A. A.; Dubina, M. V.

    2014-10-01

    Photodynamic therapy is a cancer treatment method is used primarily continuous mode laser radiation. At high power density irradiation occurs intense consumption of molecular oxygen and this caused hypoxic tumor tissue, which leads to inefficiency PDT. In this paper, pulsed and continuous irradiation modes during PDT photosensitizer Radachlorin were compared. A mathematical model for the generation of singlet oxygen 1O2 in tumor cells during photodynamic therapy with tissue oxygenation was developed. Our study theoretically and experimentally demonstrates the increased singlet oxygen generation efficiency in a pulsed irradiation mode compared to continuous wave mode with the same power density 20mW/cm2. Experimental in vitro showed that pulsed irradiation mode mostly induces apoptosis k562 tumor cells at irradiation doses of k562 1.25 - 2.5J/cm2 while the continuous mode induced necrosis.

  11. Creating opal-templated continuous conducting polymer films with ultralow percolation thresholds using thermally stable nanoparticles.

    PubMed

    Kang, Dong Jin; Kwon, Taegyun; Kim, Minsoo P; Cho, Chul-Hee; Jung, Hyunjung; Bang, Joona; Kim, Bumjoon J

    2011-11-22

    We propose a novel and robust strategy for creating continuous conducting polymer films with ultralow percolation thresholds using polymer-coated gold nanoparticles (Au NPs) as surfactant. Continuous poly(triphenylamine) (PTPA) films of high internal phase polymeric emulsions were fabricated using an assembly of cross-linked polystyrene (PS) colloidal particles as template. Polymer-coated Au NPs were designed to be thermally stable even above 200 °C and neutral to both the PS and PTPA phases. Therefore, the Au NPs localize at the PS/PTPA interface and function as surfactant to efficiently produce a continuous conducting PTPA polymer film with very low percolation thresholds. The volume fraction threshold for percolation of the PTPA phase with insulating PS colloids (as measured by electron microscopy and conductivity measurements) was found to be 0.20. In contrast, with the addition of an extremely low volume fraction (φ(p) = 0.35 vol %) of surfactant Au NPs, the volume fraction threshold for percolation of the PTPA phase was dramatically reduced to 0.05. The SEM and TEM measurements clearly demonstrated the formation of a continuous PTPA phase within the polyhedral phase of PS colloids. To elucidate the influence of the nanoparticle surfactant on the blend films, the morphology and conductivity of the blends at different PS colloid/PTPA volume ratios were carefully characterized as a function of the Au NP concentration. Our approach provides a methodology for a variety of applications that require a continuous phase for the transport of molecular species, ions, or electrons at low concentrations and a second phase for mechanical support or the conduction of a separate species.

  12. Suppression of thermal conductivity by rattling modes in thermoelectric sodium cobaltate

    NASA Astrophysics Data System (ADS)

    Voneshen, D. J.; Refson, K.; Borissenko, E.; Krisch, M.; Bosak, A.; Piovano, A.; Cemal, E.; Enderle, M.; Gutmann, M. J.; Hoesch, M.; Roger, M.; Gannon, L.; Boothroyd, A. T.; Uthayakumar, S.; Porter, D. G.; Goff, J. P.

    2013-11-01

    The need for both high electrical conductivity and low thermal conductivity creates a design conflict for thermoelectric systems, leading to the consideration of materials with complicated crystal structures. Rattling of ions in cages results in low thermal conductivity, but understanding the mechanism through studies of the phonon dispersion using momentum-resolved spectroscopy is made difficult by the complexity of the unit cells. We have performed inelastic X-ray and neutron scattering experiments that are in remarkable agreement with our first-principles density-functional calculations of the phonon dispersion for thermoelectric Na0.8CoO2, which has a large-period superstructure. We have directly observed an Einstein-like rattling mode at low energy, involving large anharmonic displacements of the sodium ions inside multi-vacancy clusters. These rattling modes suppress the thermal conductivity by a factor of six compared with vacancy-free NaCoO2. Our results will guide the design of the next generation of materials for applications in solid-state refrigerators and power recovery.

  13. Optimization of transonic wind tunnel data acquisition and control systems for providing continuous mode tests

    NASA Astrophysics Data System (ADS)

    Petronevich, V. V.

    2016-10-01

    The paper observes the issues related to the increase of efficiency and information content of experimental research in transonic wind tunnels (WT). In particular, questions of optimizing the WT Data Acquisition and Control Systems (DACS) to provide the continuous mode test method are discussed. The problem of Mach number (M number) stabilization in the test section of the large transonic compressor-type wind tunnels at subsonic flow conditions with continuous change of the aircraft model angle of attack is observed on the example of T-128 wind tunnel. To minimize the signals distortion in T-128 DACS measurement channels the optimal MGCplus filter settings of the data acquisition system used in T-128 wind tunnel to measure loads were experimentally determined. As a result of the tests performed a good agreement of the results of balance measurements for pitch/pause and continuous test modes was obtained. Carrying out balance tests for pitch/pause and continuous test methods was provided by the regular data acquisition and control system of T-128 wind tunnel with unified software package POTOK. The architecture and functional abilities of POTOK software package are observed.

  14. Continuous-variable entanglement and quantum-state teleportation between optical and macroscopic vibrational modes through radiation pressure

    SciTech Connect

    Pirandola, Stefano; Mancini, Stefano; Vitali, David; Tombesi, Paolo

    2003-12-01

    We study an isolated, perfectly reflecting, mirror illuminated by an intense laser pulse. We show that the resulting radiation pressure efficiently entangles a mirror vibrational mode with the two reflected optical sideband modes of the incident carrier beam. The entanglement of the resulting three-mode state is studied in detail and it is shown to be robust against the mirror mode temperature. We then show how this continuous-variable entanglement can be profitably used to teleport an unknown quantum state of an optical mode onto the vibrational mode of the mirror.

  15. Adiabatic theorem and continuous coupled-mode theory for efficient taper transitions in photonic crystals.

    PubMed

    Johnson, Steven G; Bienstman, Peter; Skorobogatiy, M A; Ibanescu, Mihai; Lidorikis, Elefterios; Joannopoulos, J D

    2002-12-01

    We prove that an adiabatic theorem generally holds for slow tapers in photonic crystals and other strongly grated waveguides with arbitrary index modulation, exactly as in conventional waveguides. This provides a guaranteed pathway to efficient and broad-bandwidth couplers with, e.g., uniform waveguides. We show that adiabatic transmission can only occur, however, if the operating mode is propagating (nonevanescent) and guided at every point in the taper. Moreover, we demonstrate how straightforward taper designs in photonic crystals can violate these conditions, but that adiabaticity is restored by simple design principles involving only the independent band structures of the intermediate gratings. For these and other analyses, we develop a generalization of the standard coupled-mode theory to handle arbitrary nonuniform gratings via an instantaneous Bloch-mode basis, yielding a continuous set of differential equations for the basis coefficients. We show how one can thereby compute semianalytical reflection and transmission through crystal tapers of almost any length, using only a single pair of modes in the unit cells of uniform gratings. Unlike other numerical methods, our technique becomes more accurate as the taper becomes more gradual, with no significant increase in the computation time or memory. We also include numerical examples comparing to a well-established scattering-matrix method in two dimensions.

  16. Continuous production of flexible carbon nanotube-based transparent conductive films.

    PubMed

    Fraser, I Stuart; Motta, Marcelo S; Schmidt, Ron K; Windle, Alan H

    2010-08-01

    This work shows a simple, single-stage, scalable method for the continuous production of high-quality carbon nanotube-polymer transparent conductive films from carbon feedstock. Besides the ease of scalability, a particular advantage of this process is that the concentration of nanotubes in the films, and thus transparency and conductivity, can be adjusted by changing simple process parameters. Therefore, films can be readily prepared for any application desired, ranging from solar cells to flat panel displays. Our best results show a surface resistivity of the order of 300 Ω square(-1) for a film with 80% transparency, which is promising at this early stage of process development.

  17. Continuous production of flexible carbon nanotube-based transparent conductive films

    NASA Astrophysics Data System (ADS)

    Fraser, I. Stuart; Motta, Marcelo S.; Schmidt, Ron K.; Windle, Alan H.

    2010-08-01

    This work shows a simple, single-stage, scalable method for the continuous production of high-quality carbon nanotube-polymer transparent conductive films from carbon feedstock. Besides the ease of scalability, a particular advantage of this process is that the concentration of nanotubes in the films, and thus transparency and conductivity, can be adjusted by changing simple process parameters. Therefore, films can be readily prepared for any application desired, ranging from solar cells to flat panel displays. Our best results show a surface resistivity of the order of 300 Ω square-1 for a film with 80% transparency, which is promising at this early stage of process development.

  18. Individually injected current pulses with conducting-tip, tapping-mode atomic force microscopy

    NASA Astrophysics Data System (ADS)

    Fein, Asa; Zhao, Yanming; Peterson, Charles A.; Jabbour, Ghassan E.; Sarid, Dror

    2001-12-01

    Individually injected current pulses during the operation of a conducting-tip tapping-mode atomic force microscope have been measured under a range of experimental conditions. The bias pulses, applied during the tip-sample contact time, did not perturb the tapping operations, and eliminated artifacts associated with displacement currents. The reproducible injection of current density pulses on the order of 10 μA/nm2 per tap can be applied to spreading resistance measurements and to storage applications employing, for example, phase change by Joule heating and magnetic switching by spin-polarized current.

  19. Continuous-flow electrophoresis: Membrane-associated deviations of buffer pH and conductivity

    NASA Technical Reports Server (NTRS)

    Smolka, A. J. K.; Mcguire, J. K.

    1978-01-01

    The deviations in buffer pH and conductivity which occur near the electrode membranes in continuous-flow electrophoresis were studied in the Beckman charged particle electrophoresis system and the Hanning FF-5 preparative electrophoresis instrument. The nature of the membranes separating the electrode compartments from the electrophoresis chamber, the electric field strength, and the flow rate of electrophoresis buffer were all found to influence the formation of the pH and conductivity gradients. Variations in electrode buffer flow rate and the time of electrophoresis were less important. The results obtained supported the hypothesis that a combination of Donnan membrane effects and the differing ionic mobilities in the electrophoresis buffer was responsible for the formation of the gradients. The significance of the results for the design and stable operation of continuous-flow electrophoresis apparatus was discussed.

  20. Scaling of Electron Thermal Conductivity during the Transition between Slab and Mixed Slab-Toroidal ETG Mode

    NASA Astrophysics Data System (ADS)

    Sokolov, Vladimir; Balbaky, Abed; Sen, Amiya K.

    2015-11-01

    Transition from the slab to the toroidal branch of the electron temperature gradient (ETG) mode has been successfully achieved in a basic experiment in Columbia Linear Machine CLM. We found a modest increase in saturated ETG potential fluctuations (~ 2 ×) and a substantial increase in the power density of individual mode peaks (~ 4 - 5 ×) with increased levels of curvature. We have obtained a set of experimental scalings for electron thermal conductivity χ⊥e as a function of the inverse radius of curvature Rc-1 for different fluctuation levels of the initial slab ETG mode. We found that thermal conductivity for pure slab modes is larger than it is for mixed slab-toroidal ETG modes with the same level of mode fluctuation. This effective reduction in diffusive transport can be partly explained by the flute nature of the toroidal ETG mode. This research was supported by the Department of Electrical Engineering of Columbia University.

  1. Continuous-variable quantum computing in optical time-frequency modes using quantum memories.

    PubMed

    Humphreys, Peter C; Kolthammer, W Steven; Nunn, Joshua; Barbieri, Marco; Datta, Animesh; Walmsley, Ian A

    2014-09-26

    We develop a scheme for time-frequency encoded continuous-variable cluster-state quantum computing using quantum memories. In particular, we propose a method to produce, manipulate, and measure two-dimensional cluster states in a single spatial mode by exploiting the intrinsic time-frequency selectivity of Raman quantum memories. Time-frequency encoding enables the scheme to be extremely compact, requiring a number of memories that are a linear function of only the number of different frequencies in which the computational state is encoded, independent of its temporal duration. We therefore show that quantum memories can be a powerful component for scalable photonic quantum information processing architectures.

  2. Temporal-mode continuous-variable cluster states using linear optics

    SciTech Connect

    Menicucci, Nicolas C.

    2011-06-15

    An extensible experimental design for optical continuous-variable cluster states of arbitrary size using four offline (vacuum) squeezers and six beam splitters is presented. This method has all the advantages of a temporal-mode encoding [Phys. Rev. Lett. 104, 250503 (2010)], including finite requirements for coherence and stability even as the computation length increases indefinitely, with none of the difficulty of inline squeezing. The extensibility stems from a construction based on Gaussian projected entangled pair states. The potential for use of this design within a fully fault-tolerant model is discussed.

  3. Extraction and optimization of classification rules for continuous or mixed-mode data using neural nets

    NASA Astrophysics Data System (ADS)

    Wang, Dianhui; Dillon, T. S.

    2001-03-01

    Extracting and optimizing rules from continuous or mixed- mode data directly for pattern classification problems is a challenging problem. Self-organizing neural-nets are employed to initialize the rules. A regularization model which trades off misclassification rate, recognition rate and generalization ability is first presented for refining the initial rules. To generate rules for patterns with lower probability density but considerable conceptual importance, an approach to iteratively resolving the clustering part for a filtered set of data is used. The methodology is evaluated using Iris data and demonstrates the effectiveness of technique.

  4. Studies with sample conductivity, insertion rates, and particle deflection in a continuous flow electrophoresis system

    NASA Technical Reports Server (NTRS)

    Williams, G., Jr.

    1982-01-01

    The continuous flow electrophoresis system makes electrophoresis possible in a free-flowing film of aqueous electrolyte medium. The sample continuously enters the electrolyte at the top of the chamber and is subjected to the action of a lateral dc field. This divides the sample into fractions since each component has a distinctive electrophoretic mobility. Tests were made using monodisperse polystyrene latex microspheres to determine optimum sample conductivity, insertion rates and optimum electric field applications as baseline data for future STS flight experiments. Optimum sample flow rates for the selected samples were determined to be approximately 26 micro-liters/min. Experiments with samples in deionized water yielded best results and voltages in the 20 V/cm to 30 V/cm range were optimum. Deflections of formaldehyde fixed turkey and bovine erythrocytes were determined using the continuous flow electrophoresis system. The effects of particle interactions on sample resolution and migration in the chamber was also evaluated.

  5. Studies with sample conductivity, insertion rates, and particle deflection in a continuous flow electrophoresis system

    NASA Technical Reports Server (NTRS)

    Williams, G., Jr.

    1982-01-01

    The continuous flow electrophoresis system makes electrophoresis possible in a free-flowing film of aqueous electrolyte medium. The sample continuously enters the electrolyte at the top of the chamber and is subjected to the action of a lateral dc field. This divides the sample into fractions since each component has a distinctive electrophoretic mobility. Tests were made using monodisperse polystyrene latex microspheres to determine optimum sample conductivity, insertion rates and optimum electric field applications as baseline data for future STS flight experiments. Optimum sample flow rates for the selected samples were determined to be approximately 26 micro-liters/min. Experiments with samples in deionized water yielded best results and voltages in the 20 V/cm to 30 V/cm range were optimum. Deflections of formaldehyde fixed turkey and bovine erythrocytes were determined using the continuous flow electrophoresis system. The effects of particle interactions on sample resolution and migration in the chamber was also evaluated.

  6. Ionic limiting molar conductivity calculation of Li-ion battery electrolyte based on mode coupling theory.

    PubMed

    He, Xiangming; Pu, Weihua; Han, Jingli; Chen, Jian; Lu, Jiufang; Jiang, Changyin; Wan, Chunrong

    2005-12-15

    A method is proposed based on mode coupling theory in which the ion transference number is introduced into the theory. The ionic limiting molar conductivities of LiPF6, LiClO4, LiBF4, LiCF3SO3, Li(CF3SO3)2N, LiC4F9SO3, and LiAsF6 in PC(propylene carbonate), GBL(gamma-butyrolactone), PC(propylene carbonate)/EMC(ethylmethyl carbonate), and PC(propylene carbonate)/DME(dimethoxyethane) are calculated based on this method, which does not involve any adjustable parameter. The results fit well to the literature data which are calculated by an empirically adjusted formula. This presents a potential way to calculate the conductivities of Li-ion battery electrolytes.

  7. A review on the flexural mode of graphene: lattice dynamics, thermal conduction, thermal expansion, elasticity and nanomechanical resonance.

    PubMed

    Jiang, Jin-Wu; Wang, Bing-Shen; Wang, Jian-Sheng; Park, Harold S

    2015-03-04

    Single-layer graphene is so flexible that its flexural mode (also called the ZA mode, bending mode, or out-of-plane transverse acoustic mode) is important for its thermal and mechanical properties. Accordingly, this review focuses on exploring the relationship between the flexural mode and thermal and mechanical properties of graphene. We first survey the lattice dynamic properties of the flexural mode, where the rigid translational and rotational invariances play a crucial role. After that, we outline contributions from the flexural mode in four different physical properties or phenomena of graphene-its thermal conductivity, thermal expansion, Young's modulus and nanomechanical resonance. We explain how graphene's superior thermal conductivity is mainly due to its three acoustic phonon modes at room temperature, including the flexural mode. Its coefficient of thermal expansion is negative in a wide temperature range resulting from the particular vibration morphology of the flexural mode. We then describe how the Young's modulus of graphene can be extracted from its thermal fluctuations, which are dominated by the flexural mode. Finally, we discuss the effects of the flexural mode on graphene nanomechanical resonators, while also discussing how the essential properties of the resonators, including mass sensitivity and quality factor, can be enhanced.

  8. Hemodynamic effects of various support modes of continuous flow LVADs on the cardiovascular system: A numerical study

    PubMed Central

    Song, Zhiming; Gu, Kaiyun; Gao, Bin; Wan, Feng; Chang, Yu; Zeng, Yi

    2014-01-01

    Background The aim of this study was to determine the hemodynamic effects of various support modes of continuous flow left ventricular assist devices (CF-LVADs) on the cardiovascular system using a numerical cardiovascular system model. Material/Methods Three support modes were selected for controlling the CF-LVAD: constant flow mode, constant speed mode, and constant pressure head mode of CF-LVAD. The CF-LVAD is established between the left ventricular apex and the ascending aorta, and was incorporated into the numerical model. Various parameters were evaluated, including the blood assist index (BAI), the left ventricular external work (LVEW), the energy of blood flow (EBF), pulsatility index (PI), and surplus hemodynamic energy (SHE). Results The results show that the constant flow mode, when compared to the constant speed mode and the constant pressure head mode, increases LVEW by 31% and 14%, and EBF by 21% and 15%, respectively, indicating that this mode achieved the best ventricular unloading among the 3 support modes. As BAI is increased, PI and SHE are gradually decreased, whereas PI of the constant pressure head reaches the maximum value. Conclusions The study demonstrates that the continuous flow control mode of the CF-LVAD may achieve the highest ventricular unloading. In contrast, the constant rotational speed mode permits the optimal blood perfusion. Finally, the constant pressure head strategy, permitting optimal pulsatility, should optimize the vascular function. PMID:24793178

  9. Continuous Variable Cluster State Generation over the Optical Spatial Mode Comb

    DOE PAGES

    Pooser, Raphael C.; Jing, Jietai

    2014-10-20

    One way quantum computing uses single qubit projective measurements performed on a cluster state (a highly entangled state of multiple qubits) in order to enact quantum gates. The model is promising due to its potential scalability; the cluster state may be produced at the beginning of the computation and operated on over time. Continuous variables (CV) offer another potential benefit in the form of deterministic entanglement generation. This determinism can lead to robust cluster states and scalable quantum computation. Recent demonstrations of CV cluster states have made great strides on the path to scalability utilizing either time or frequency multiplexingmore » in optical parametric oscillators (OPO) both above and below threshold. The techniques relied on a combination of entangling operators and beam splitter transformations. Here we show that an analogous transformation exists for amplifiers with Gaussian inputs states operating on multiple spatial modes. By judicious selection of local oscillators (LOs), the spatial mode distribution is analogous to the optical frequency comb consisting of axial modes in an OPO cavity. We outline an experimental system that generates cluster states across the spatial frequency comb which can also scale the amount of quantum noise reduction to potentially larger than in other systems.« less

  10. Effect of instantaneous and continuous quenches on the density of vibrational modes in model glasses

    NASA Astrophysics Data System (ADS)

    Lerner, Edan; Bouchbinder, Eran

    2017-08-01

    Computational studies of supercooled liquids often focus on various analyses of their "underlying inherent states"—the glassy configurations at zero temperature obtained by an infinitely fast (instantaneous) quench from equilibrium supercooled states. Similar protocols are also regularly employed in investigations of the unjamming transition at which the rigidity of decompressed soft-sphere packings is lost. Here we investigate the statistics and localization properties of low-frequency vibrational modes of glassy configurations obtained by such instantaneous quenches. We show that the density of vibrational modes grows as ωβ with β depending on the parent temperature T0 from which the glassy configurations were instantaneously quenched. For quenches from high temperature liquid states we find β ≈3 , whereas β appears to approach the previously observed value β =4 as T0 approaches the glass transition temperature. We discuss the consistency of our findings with the theoretical framework of the soft potential model, and contrast them with similar measurements performed on configurations obtained by continuous quenches at finite cooling rates. Our results suggest that any physical quench at rates sufficiently slower than the inverse vibrational time scale—including all physically realistic quenching rates of molecular or atomistic glasses—would result in a glass whose density of vibrational modes is universally characterized by β =4 .

  11. Continuous Variable Cluster State Generation over the Optical Spatial Mode Comb

    SciTech Connect

    Pooser, Raphael C.; Jing, Jietai

    2014-10-20

    One way quantum computing uses single qubit projective measurements performed on a cluster state (a highly entangled state of multiple qubits) in order to enact quantum gates. The model is promising due to its potential scalability; the cluster state may be produced at the beginning of the computation and operated on over time. Continuous variables (CV) offer another potential benefit in the form of deterministic entanglement generation. This determinism can lead to robust cluster states and scalable quantum computation. Recent demonstrations of CV cluster states have made great strides on the path to scalability utilizing either time or frequency multiplexing in optical parametric oscillators (OPO) both above and below threshold. The techniques relied on a combination of entangling operators and beam splitter transformations. Here we show that an analogous transformation exists for amplifiers with Gaussian inputs states operating on multiple spatial modes. By judicious selection of local oscillators (LOs), the spatial mode distribution is analogous to the optical frequency comb consisting of axial modes in an OPO cavity. We outline an experimental system that generates cluster states across the spatial frequency comb which can also scale the amount of quantum noise reduction to potentially larger than in other systems.

  12. Treatment of dairy manure using the microwave enhanced advanced oxidation process under a continuous mode operation.

    PubMed

    Yu, Yang; Lo, Ing W; Liao, Ping H; Lo, Kwang V

    2010-11-01

    The microwave enhanced advanced oxidation process (MW/H(2)O(2)-AOP) was used to treat dairy manure for solubilization of nutrients and organic matters. This study investigated the effectiveness of the MW/H(2)O(2)-AOP under a continuous mode of operation, and compared the results to those of batch operations. The main factors affecting solubilization by the MW/H(2)O(2)-AOP were heating temperature and hydrogen peroxide dosage. Soluble chemical oxygen demand (SCOD) and volatile fatty acids (VFA) increased with an increase of microwave (MW) heating temperature; very high concentrations were obtained at 90°C. Insignificant amounts of ammonia and reducing sugars were released in all runs. An acidic pH condition was required for phosphorus solubilisation from dairy manure. The best yield was obtained at 90°C with an acid dosage of 1.0 %; about 92 % of total phosphorus and 90 % of total chemical oxygen demand were in the soluble forms. The MW/H(2)O(2)-AOP operated in a continuous operation mode showed pronounced synergistic effects between hydrogen peroxide and microwave irradiation when compared to a batch system under similar operating conditions, resulting in much better yields.

  13. Evidence for a Clathrin-independent mode of endocytosis at a continuously active sensory synapse

    PubMed Central

    Fuchs, Michaela; Brandstätter, Johann Helmut; Regus-Leidig, Hanna

    2014-01-01

    Synaptic vesicle exocytosis at chemical synapses is followed by compensatory endocytosis. Multiple pathways including Clathrin-mediated retrieval of single vesicles, bulk retrieval of large cisternae, and kiss-and-run retrieval have been reported to contribute to vesicle recycling. Particularly at the continuously active ribbon synapses of retinal photoreceptor and bipolar cells, compensatory endocytosis plays an essential role to provide ongoing vesicle supply. Yet, little is known about the mechanisms that contribute to endocytosis at these highly complex synapses. To identify possible specializations in ribbon synaptic endocytosis during different states of activity, we exposed mice to controlled lighting conditions and compared the distribution of endocytotic proteins at rod and cone photoreceptor, and ON bipolar cell ribbon synapses with light and electron microscopy. In mouse ON bipolar cell terminals, Clathrin-mediated endocytosis seemed to be the dominant mode of endocytosis at all adaptation states analyzed. In contrast, in mouse photoreceptor terminals in addition to Clathrin-coated pits, clusters of membranously connected electron-dense vesicles appeared during prolonged darkness. These clusters labeled for Dynamin3, Endophilin1, and Synaptojanin1, but not for AP180, Clathrin LC, and hsc70. We hypothesize that rod and cone photoreceptors possess an additional Clathrin-independent mode of vesicle retrieval supporting the continuous synaptic vesicle supply during prolonged high activity. PMID:24616664

  14. Cell-compatible conducting polyaniline films prepared in colloidal dispersion mode.

    PubMed

    Kašpárková, Věra; Humpolíček, Petr; Capáková, Zdenka; Bober, Patrycja; Stejskal, Jaroslav; Trchová, Miroslava; Rejmontová, Petra; Junkar, Ita; Lehocký, Marián; Mozetič, Miran

    2017-09-01

    Conducting polyaniline can be prepared and modified using several procedures, all of which can significantly influence its applicability in different fields of biomedicine or biotechnology. The modifications of surface properties are crucial with respect to the possible applications of this polymer in tissue engineering or as biosensors. Innovative technique for preparing polyaniline films via in-situ polymerization in colloidal dispersion mode using four stabilizers (poly-N-vinylpyrrolidone; sodium dodecylsulfate; Tween 20 and Pluronic F108) was developed. The surface energy, conductivity, spectroscopic features, and cell compatibility of thin polyaniline films were determined using contact-angle measurement, the van der Pauw method, Fourier-transform infrared spectroscopy, and assay conducted on mouse fibroblasts, respectively. The stabilizers significantly influenced not only the surface and electrical properties of the films but also their cell compatibility. Sodium dodecylsulfate seems preferentially to combine both the high conductivity and good cell compatibility. Moreover, the films with sodium dodecylsulfate were non-irritant for skin, which was confirmed by their in-vitro exposure to the 3D-reconstructed human tissue model. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. 20 CFR 404.1589 - We may conduct a review to find out whether you continue to be disabled.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false We may conduct a review to find out whether you continue to be disabled. 404.1589 Section 404.1589 Employees' Benefits SOCIAL SECURITY... Continuing Or Stopping Disability § 404.1589 We may conduct a review to find out whether you continue to...

  16. Continuous Patterning of Copper Nanowire-Based Transparent Conducting Electrodes for Use in Flexible Electronic Applications.

    PubMed

    Zhong, Zhaoyang; Lee, Hyungjin; Kang, Dongwoo; Kwon, Sin; Choi, Young-Man; Kim, Inhyuk; Kim, Kwang-Young; Lee, Youngu; Woo, Kyoohee; Moon, Jooho

    2016-08-23

    Simple, low-cost and scalable patterning methods for Cu nanowire (NW)-based flexible transparent conducting electrodes (FTCEs) are essential for the widespread use of Cu NW FTCEs in numerous flexible optoelectronic devices, wearable devices, and electronic skins. In this paper, continuous patterning for Cu NW FTCEs via a combination of selective intense pulsed light (IPL) and roll-to-roll (R2R) wiping process was explored. The development of continuous R2R patterning could be achieved because there was significant difference in adhesion properties between NWs and substrates depending on whether Cu NW coated area was irradiated by IPL or not. Using a custom-built, R2R-based wiping apparatus, it was confirmed that nonirradiated NWs could be clearly removed out without any damage on irradiated NWs strongly adhered to the substrate, resulting in continuous production of low-cost Cu NW FTCE patterns. In addition, the variations in microscale pattern size by varying IPL process parameters/the mask aperture sizes were investigated, and possible factors affecting on developed pattern size were meticulously examined. Finally, the successful implementation of the patterned Cu NW FTCEs into a phosphorescent organic light-emitting diode (PhOLED) and a flexible transparent conductive heater (TCH) were demonstrated, verifying the applicability of the patterned FTCEs. It is believed that our study is the key step toward realizing the practical use of NW FTCEs in various flexible electronic devices.

  17. Stabilization of the Resistive Wall Mode and Error Field Reduction by a Rotating Conducting Wall

    NASA Astrophysics Data System (ADS)

    Paz-Soldan, Carlos

    2011-10-01

    The hypothesis that the Resistive Wall Mode (RWM) can be stabilized by high-speed differentially-rotating conducting walls is tested in a linear device. This geometry allows the use of cylindrical solid metal walls, whereas a torus would require a flowing liquid metal. Experiments over the past year have for the first time explored RWM stability with a rotating copper wall capable of achieving speeds (rΩw) of up to 280 km/h, equivalent to a magnetic Reynolds number (Rm) of 5. The main results are: 1) Wall rotation increases the stability window of the RWM, allowing ~ 25% more plasma current (Ip) at Rm = 5 while maintaining MHD stability. 2) Error field reduction below a critical value allows the observation of initial mode rotation, followed by braking, wall-locking, and subsequent faster growth. 3) Locking is found to depend on the direction of wall rotation (Ω̂w) with respect to the intrinsic plasma rotation, with locking to both the static wall (vacuum vessel) and rotating wall observed. Additionally, indirect effects on RWM stability are observed via the effect of wall rotation on device error fields. Wall rotation shields locking error fields, which reduces the braking torque and inhibits mode-locking. The linear superposition of error fields from guide field (Bz) solenoid misalignments and current-carrying leads is also shown to break symmetry in Ω̂w , with one direction causing stronger error fields and earlier locking irrespective of plasma flow. Vacuum field measurements further show that rotation decreases the error field penetration time and advects the field to a different orientation, as predicted by theory. Experiments are conducted on the Rotating Wall Machine, a 1.2 m long and 16 cm diameter screw-pinch with Bz ~ 500 G, where hollow-cathode injectors are biased to source up to 7 kA of Ip, exciting current-driven RWMs. MHD activity is measured through 120 edge Br, Bθ, Bz probes as well as internal Bdot, Langmuir and Mach probes. RWM

  18. Conduction-cooled, continuous wave, diode-laser pumped, Nd:YAG mini-slab laser

    SciTech Connect

    Shine, R.J.; Alfrey, A.J.; Byer, R.L.

    1994-12-31

    We have designed a low loss mounting scheme for zig- zag slab lasers. This scheme includes a Teflon AF coating to protect the slab total internal reflection (TIR) surfaces. In addition, the slab is conduction cooled through a window to isolate the water flow from the slab surfaces. This design was initially tested on a line-pumped slab laser which operated with 5 watts of output power at a pump power of 28 watts. The laser operated in a TEM sub 00 mode at all powers. The low loss protective coating allowed this laser to operate on the lower gain line of Nd:YAG at 1.32, with 1.1 watt of output power at the same pump power. Since that time, a higher power laser has been built. This laser operates with a 20% slope efficiency, with an output power of 30 watts at a pump power of 160 watts.

  19. Continuous versus step-by-step scanning mode of a novel 3D scanner for CyberKnife measurements.

    PubMed

    Al Kafi, M Abdullah; Mwidu, Umar; Moftah, Belal

    2015-11-01

    The purpose of the study is to investigate the continuous versus step-by-step scanning mode of a commercial circular 3D scanner for commissioning measurements of a robotic stereotactic radiosurgery system. The 3D scanner was used for profile measurements in step-by-step and continuous modes with the intent of comparing the two scanning modes for consistency. The profile measurements of in-plane, cross-plane, 15 degree, and 105 degree were performed for both fixed cones and Iris collimators at depth of maximum dose and at 10cm depth. For CyberKnife field size, penumbra, flatness and symmetry analysis, it was observed that the measurements with continuous mode, which can be up to 6 times faster than step-by-step mode, are comparable and produce scans nearly identical to step-by-step mode. When compared with centered step-by-step mode data, a fully processed continuous mode data gives rise to maximum of 0.50% and 0.60% symmetry and flatness difference respectfully for all the fixed cones and Iris collimators studied.

  20. Current distribution in tissues with conducted electrical weapons operated in drive-stun mode.

    PubMed

    Panescu, Dorin; Kroll, Mark W; Brave, Michael

    2016-08-01

    The TASER® conducted electrical weapon (CEW) is best known for delivering electrical pulses that can temporarily incapacitate subjects by overriding normal motor control. The alternative drive-stun mode is less understood and the goal of this paper is to analyze the distribution of currents in tissues when the CEW is operated in this mode. Finite element modeling (FEM) was used to approximate current density in tissues with boundary electrical sources placed 40 mm apart. This separation was equivalent to the distance between drive-stun mode TASER X26™, X26P, X2 CEW electrodes located on the device itself and between those located on the expended CEW cartridge. The FEMs estimated the amount of current flowing through various body tissues located underneath the electrodes. The FEM simulated the attenuating effects of both a thin and of a normal layer of fat. The resulting current density distributions were used to compute the residual amount of current flowing through deeper layers of tissue. Numerical modeling estimated that the skin, fat and skeletal muscle layers passed at least 86% or 91% of total CEW current, assuming a thin or normal fat layer thickness, respectively. The current density and electric field strength only exceeded thresholds which have increased probability for ventricular fibrillation (VFTJ), or for cardiac capture (CCTE), in the skin and the subdermal fat layers. The fat layer provided significant attenuation of drive-stun CEW currents. Beyond the skeletal muscle layer, only fractional amounts of the total CEW current were estimated to flow. The regions presenting risk for VF induction or for cardiac capture were well away from the typical heart depth.

  1. Dosimetric properties of an amorphous-silicon EPID used in continuous acquisition mode for application to dynamic and arc IMRT

    SciTech Connect

    McCurdy, B. M. C.; Greer, P. B.

    2009-07-15

    Dosimetric properties of an amorphous-silicon electronic portal imaging device (EPID) operated in a real-time acquisition mode were investigated. This mode will be essential for time-resolved dose verification of dynamic (sliding window) intensity modulated radiation therapy (IMRT) and intensity modulated arc radiation therapy (arc-IMRT). The EPID was used in continuous acquisition mode (i.e., ''cine'' mode) where individual sequential image frames are acquired in real time. The properties studied include dose linearity, reproducibility of response, and image stability. Results of using the continuous acquisition mode with several example treatments including dynamic IMRT, arc treatment, and single-arc-IMRT are compared to results using the well-studied integrated acquisition mode (i.e., ''frame averaging'' or ''IMRT'' mode). Real-time EPID response was also compared to real-time ion-chamber data for selected points in the deliveries. The example treatment deliveries in both continuous and integrated acquisition modes were converted to arbitrary EPID dose units via a calibration field. The summation of all acquired continuous mode images was compared using percentage dose difference to the single image acquired in the integrated mode using in-field pixels only (defined as those pixels >10% of maximum, in-field signal). Using the continuous acquisition mode, the EPID response was not linear with dose. It was found that the continuous mode dose response corresponded approximately to dropping one image per acquisition session. Reproducibility of EPID response to low monitor units (MUs) was found to be poor but greatly improved with increasing MU. Open field profiles were found to be stable in the cross-plane direction but required several frames to become stable in the in-plane direction. However, both of these issues are clinically insignificant due to arc-IMRT deliveries requiring relatively large monitor units (>100 MU). Analysis of the five IMRT, arc, and arc

  2. High Thermal Conductivity Cryogenic RF Feedthroughs for Higher Order Mode Couplers

    SciTech Connect

    Charles Reece; Edward Daly; Thomas Elliott; H. Phillips; Joseph Ozelis; Timothy Rothgeb; Katherine Wilson; Genfa Wu

    2005-05-01

    The use of higher-order-mode (HOM) pickup probes in the presence of significant fundamental RF fields can present a thermal challenge for CW or high average power SRF cavity applications. The electric field probes on the HOM-damping couplers on the JLab ''High Gradient'' (HG) and ''Low Loss'' (LL) seven-cell cavities for the CEBAF upgrade are exposed to approximately 10% of the peak magnetic field in the cavity. To avoid significant dissipative losses, these probes must remain superconducting during operation. Typical cryogenic rf feedthroughs provide a poor thermal conduction path for the probes and provide inadequate stabilization. We have developed solutions that meet the requirements, providing a direct thermal path from the niobium probe, thorough single-crystal sapphire, to bulk copper which can be thermally anchored. Designs, electromagnetic and thermal analyses, and performance data will be presented.

  3. Continuous electrodeposition for lightweight, highly conducting and strong carbon nanotube-copper composite fibers.

    PubMed

    Xu, Geng; Zhao, Jingna; Li, Shan; Zhang, Xiaohua; Yong, Zhenzhong; Li, Qingwen

    2011-10-05

    Carbon nanotube (CNT) fiber is a promising candidate for lightweight cables. The introduction of metal particles on a CNT fiber can effectively improve its electrical conductivity. However, the decrease in strength is observed in CNT-metal composite fibers. Here we demonstrate a continuous process, which combines fiber spinning, CNT anodization and metal deposition, to fabricate lightweight and high-strength CNT-Cu fibers with metal-like conductivities. The composite fiber with anodized CNTs exhibits a conductivity of 4.08 × 10(4)-1.84 × 10(5) S cm(-1) and a mass density of 1.87-3.08 g cm(-3), as the Cu thickness is changed from 1 to 3 μm. It can be 600-811 MPa in strength, as strong as the un-anodized pure CNT fiber (656 MPa). We also find that during the tensile tests there are slips between the inner CNTs and the outer Cu layer, leading to the drops in electrical conductivity. Therefore, there is an effective fiber strength before which the Cu layer is robust. Due to the improved interfacial bonding between the Cu layer and the anodized CNT surfaces, such effective strength is still high, up to 490-570 MPa.

  4. 2.1 kW single mode continuous wave monolithic fiber laser

    NASA Astrophysics Data System (ADS)

    Rosales-Garcia, Andrea; Tobioka, Hideaki; Abedin, Kazi; Dong, Hao; Várallyay, Zoltán.; Szabó, Áron; Taunay, Thierry; Sullivan, Sean; Headley, Clifford

    2015-03-01

    A robust, alignment-free monolithic 2.1 kW single-mode continuous wave fiber laser, operating at 1083 nm is demonstrated. The laser is pumped with commercial fiber pigtailed multimode diodes through all-fiber pump-signal power combiners in a MOPA architecture. The oscillator was formed with high reflector and output coupler fiber Bragg gratings written in 11/200 μm (mode field/cladding diameter) single-mode fiber. The gain medium was a 19m OFS commercial 11/200 μm double clad Yb-doped fiber (DCY). Pump light was coupled to the oscillator using two 11/200 μm pump-signal power combiners (PSC). A total of 20 commercially available 58W pump diodes at 915 nm were used to generate 800W of signal, as measured before the amplifier. The Raman power after the oscillator was more than 60 dB below the signal power. The amplifier was built using 13 m of 14/200 µm DCY and two (18+1)x1 PSC combiners with more than 95% pump and signal light transmission. A total of 2 kW of power was used to bi-directionally pump the amplifier. The output was measured after 3 m 14/200 μm fiber, and 10 m 100/360 μm delivery cable. Total signal output power was 2.1 kW, corresponding to an amplifier slope efficiency of 77%. The Raman power is more than 30 dB below the signal power. At maximum power, no modal instabilities, thermal effects, nor power rollover were observed. With higher power pumps, it is predicted that a power level of 2.6 kW can be achieved with the Raman level below 20 dB.

  5. Continuous high order sliding mode controller design for a flexible air-breathing hypersonic vehicle.

    PubMed

    Wang, Jie; Zong, Qun; Su, Rui; Tian, Bailing

    2014-05-01

    This paper investigates the problem of tracking control with uncertainties for a flexible air-breathing hypersonic vehicle (FAHV). In order to overcome the analytical intractability of this model, an Input-Output linearization model is constructed for the purpose of feedback control design. Then, the continuous finite time convergence high order sliding mode controller is designed for the Input-Output linearization model without uncertainties. In addition, a nonlinear disturbance observer is applied to estimate the uncertainties in order to compensate the controller and disturbance suppression, where disturbance observer and controller synthesis design is obtained. Finally, the synthesis of controller and disturbance observer is used to achieve the tracking for the velocity and altitude of the FAHV and simulations are presented to illustrate the effectiveness of the control strategies.

  6. Propagating mode-I fracture in amorphous materials using the continuous random network model

    NASA Astrophysics Data System (ADS)

    Heizler, Shay I.; Kessler, David A.; Levine, Herbert

    2011-08-01

    We study propagating mode-I fracture in two-dimensional amorphous materials using atomistic simulations. We use the continuous random network model of an amorphous material, creating samples using a two-dimensional analog of the Wooten-Winer-Weaire Monte Carlo algorithm. For modeling fracture, molecular-dynamics simulations were run on the resulting samples. The results of our simulations reproduce the main experimental features. In addition to achieving a steady-state crack under a constant driving displacement (which has not yet been achieved by other atomistic models for amorphous materials), the runs show microbranching, which increases with driving, transitioning to macrobranching for the largest drivings. In addition to the qualitative visual similarity of the simulated cracks to experiment, the simulation also succeeds in reproducing qualitatively the experimentally observed oscillations of the crack velocity.

  7. Continuous monitoring of bacterial biofilm growth using uncoated Thickness-Shear Mode resonators

    NASA Astrophysics Data System (ADS)

    Castro, P.; Resa, P.; Durán, C.; Maestre, J. R.; Mateo, M.; Elvira, L.

    2012-12-01

    Quartz Crystal Microbalances (QCM) were used to nondestructively monitor in real time the microbial growth of the bacteria Staphylococcus epidermidis (S. epidermidis) in a liquid broth. QCM, sometimes referred to as Thickness-Shear Mode (TSM) resonators, are highly sensitive sensors not only able to measure very small mass, but also non-gravimetric contributions of viscoelastic media. These devices can be used as biosensors for bacterial detection and are employed in many applications including their use in the food industry, water and environment monitoring, pharmaceutical sciences and clinical diagnosis. In this work, three strains of S. epidermidis (which differ in the ability to produce biofilm) have been continuously monitored using an array of piezoelectric TSM resonators, at 37 °C in a selective culturing media. Microbial growth was followed by measuring the changes in the crystal resonant frequency and bandwidth at several harmonics. It was shown that microbial growth can be monitored in real time using multichannel and multiparametric QCM sensors.

  8. Imaging study of a phase-sensitive breast-CT system in continuous acquisition mode

    NASA Astrophysics Data System (ADS)

    Delogu, P.; Golosio, B.; Fedon, C.; Arfelli, F.; Bellazzini, R.; Brez, A.; Brun, F.; Di Lillo, F.; Dreossi, D.; Mettivier, G.; Minuti, M.; Oliva, P.; Pichera, M.; Rigon, L.; Russo, P.; Sarno, A.; Spandre, G.; Tromba, G.; Longo, R.

    2017-01-01

    The SYRMA-CT project aims to set-up the first clinical trial of phase-contrast breast Computed Tomography with synchrotron radiation at the SYRMEP beamline of Elettra, the Italian synchrotron light source. The challenge in a dedicated breast CT is to match a high spatial resolution with a low dose level. In order to fulfil these requirements, the SYRMA-CT project uses a large area CdTe single photon counting detector (Pixirad-8), simultaneous algebraic reconstruction technique (SART) and phase retrieval pre-processing. This work investigates the imaging performances of the system in a continuous acquisition mode and with a low dose level towards the clinical application. A custom test object and a large surgical sample have been studied.

  9. Continuous-mode dielectrophoretic gating for highly efficient separation of analytes in surface micromachined microfluidic devices

    NASA Astrophysics Data System (ADS)

    Song, Hongjun; Mulukutla, Vishwanath; James, Conrad D.; Bennett, Dawn J.

    2008-12-01

    Here, we describe a dielectrophoretic (DEP) gating technique for preconcentrating and separating biological and non-biological particles in a microfluidic device. The microfluidic devices are surface-micromachined on silicon substrates and are fully encapsulated without substrate bonding procedures. DEP gates in the devices consist of embedded microelectrodes that are coupled to the fluid channels for analyte manipulation with electric fields. We consider several different microelectrode designs such as low and high radius-of-curvature edges, and we detail the time- and frequency-dependent preconcentration of particles. Simulations of the particle motion under the manipulation of DEP forces are found to be in good agreement with the experimental results. Experimental results show that bioparticles such as Penicillium brevicompactum (PBC), T-cells and Escherichia coli (E. coli) undergo positive DEP and are trapped in regions of large electric-field gradient adjacent to the DEP gate. In contrast to our previous demonstration of batch-mode separation of particles with different dielectric properties, here we perform a continuous-mode separation of latex particles and E. coli from a mixture.

  10. Thermomechanically coupled conduction mode laser welding simulations using smoothed particle hydrodynamics

    NASA Astrophysics Data System (ADS)

    Hu, Haoyue; Eberhard, Peter

    2016-10-01

    Process simulations of conduction mode laser welding are performed using the meshless Lagrangian smoothed particle hydrodynamics (SPH) method. The solid phase is modeled based on the governing equations in thermoelasticity. For the liquid phase, surface tension effects are taken into account to simulate the melt flow in the weld pool, including the Marangoni force caused by a temperature-dependent surface tension gradient. A non-isothermal solid-liquid phase transition with the release or absorption of additional energy known as the latent heat of fusion is considered. The major heat transfer through conduction is modeled, whereas heat convection and radiation are neglected. The energy input from the laser beam is modeled as a Gaussian heat source acting on the initial material surface. The developed model is implemented in Pasimodo. Numerical results obtained with the model are presented for laser spot welding and seam welding of aluminum and iron. The change of process parameters like welding speed and laser power, and their effects on weld dimensions are investigated. Furthermore, simulations may be useful to obtain the threshold for deep penetration welding and to assess the overall welding quality. A scalability and performance analysis of the implemented SPH algorithm in Pasimodo is run in a shared memory environment. The analysis reveals the potential of large welding simulations on multi-core machines.

  11. Intrinsic localized mode and low thermal conductivity of PbSe

    NASA Astrophysics Data System (ADS)

    Shulumba, Nina; Hellman, Olle; Minnich, Austin J.

    2017-01-01

    Lead chalcogenides such as PbS, PbSe, and PbTe are of interest for their exceptional thermoelectric properties and strongly anharmonic lattice dynamics. Although PbTe has received the most attention, PbSe has a lower thermal conductivity and a nonlinear temperature dependence of thermal resistivity despite being stiffer, trends that prior first-principles calculations have not fully reproduced. Here, we use ab initio calculations that explicitly account for strong anharmonicity and a computationally efficient stochastic phase-space sampling scheme to identify the origin of this low thermal conductivity as an anomalously large anharmonic interaction, exceeding in strength that in PbTe, between the transverse optic and longitudinal acoustic branches. The strong anharmonicity is reflected in the striking observation of an intrinsic localized mode that forms in the acoustic frequencies. Our work shows the deep insights into thermal phonons that can be obtained from ab initio calculations that do not rely on perturbations from the ground-state phonon dispersion.

  12. Survival of Listeria monocytogenes and Salmonella spp. on catfish exposed to microwave heating in a continuous mode

    USDA-ARS?s Scientific Manuscript database

    Microwave (MW) heating using continuous output may provide better and consistent cooking for foods. Currently, household units with a build-in inverter device are available in which the output is continuous vs. the traditional on-off mode. With an inverter, these MW ovens may provide consistent he...

  13. 20 CFR 416.989 - We may conduct a review to find out whether you continue to be disabled.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false We may conduct a review to find out whether you continue to be disabled. 416.989 Section 416.989 Employees' Benefits SOCIAL SECURITY... Blindness Continuing Or Stopping Disability Or Blindness § 416.989 We may conduct a review to find...

  14. Effect of Aural and Visual Presentation Modes on Argentine and US Musicians' Evaluations of Conducting and Choral Performance

    ERIC Educational Resources Information Center

    Madsen, Katia

    2009-01-01

    The purpose of this study was to investigate the effect of presentation modes on evaluations of conducting and choral ensemble performance. Participants (N = 36) were graduate music students with conducting and teaching experience studying in Argentina (n = 18) or the USA (n = 18). The participants viewed and evaluated a stimulus videotape that…

  15. Efficient polyhydroxyalkanoate (PHA) accumulation by a new continuous feeding mode in three-stage mixed microbial culture (MMC) PHA production process.

    PubMed

    Chen, Zhiqiang; Huang, Long; Wen, Qinxue; Guo, Zirui

    2015-09-10

    A new continuous feeding mode was developed to optimize the polyhydroxyalkanoates (PHAs) accumulation step in the three-stage PHAs production process by mixed microbial cultures (MMCs) using mixed volatile fatty acids (VFAs) as substrate. The continuous feeding assays under low biomass loading rate (BLR) (in the range of 3.5-5.5Cmol VFA/Cmol X/d) can be directly fed with feedstock with pH from 5.0 to 10.0 without any pH regulation. The maximum intracellular PHA content of 70.4% and system PHA yield (YPHA/S(sys)) of 0.81Cmol PHA/Cmol VFA were achieved under the continuous feeding mode at BLR of 3.86Cmol VFA/Cmol X/d when directly fed with substrate at pH 5. These values were higher than those under the pulse wise feeding mode with the same substrate and active biomass concentration. The results indicated that a self-balanced pH state was formed in the continuous feeding system. Further studies on the reaction pH and kinetics of the MMCs in the continuous feeding reactor were conducted to understand the pH variation mechanism and accumulation process. The optimal BLR to get high PHA content and YPHA/S(sys) was 3.5-5.5Cmol VFA/Cmol X/d. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Enhanced method to reconstruct mode shapes of continuous scanning measurements using the Hilbert Huang transform and the modal analysis method

    SciTech Connect

    Lee, Jongsuh; Hussain, Syed Hassaan; Wang, Semyung Park, Kyihwan

    2014-09-15

    Generally, it is time consuming to experimentally identify the operating deflection shape or mode shape of a structure. To overcome this problem, the Hilbert Huang transform (HHT) technique has been recently proposed. This technique is used to extract the mode shape from measurements that continuously measure the vibration of a region of interest within a structure using a non-contact laser sensor. In previous research regarding the HHT, two technical processes were needed to obtain the mode shape for each mode. The purpose of this study is to improve and complement our previous research, and for this purpose, a modal analysis approach is adapted without using the two technical processes to obtain an accurate un-damped impulse response of each mode for continuous scanning measurements. In addition, frequency response functions for each type of beam are derived, making it possible to make continuously scanned measurements along a straight profile. In this paper, the technical limitations and drawbacks of the damping compensation technique used in previous research are identified. In addition, the separation of resonant frequency (the Doppler effect) that occurs in continuous scanning measurements and the separation of damping phenomenon are also observed. The proposed method is quantitatively verified by comparing it with the results obtained from a conventional approach to estimate the mode shape with an impulse response.

  17. Enhanced method to reconstruct mode shapes of continuous scanning measurements using the Hilbert Huang transform and the modal analysis method

    NASA Astrophysics Data System (ADS)

    Lee, Jongsuh; Hussain, Syed Hassaan; Wang, Semyung; Park, Kyihwan

    2014-09-01

    Generally, it is time consuming to experimentally identify the operating deflection shape or mode shape of a structure. To overcome this problem, the Hilbert Huang transform (HHT) technique has been recently proposed. This technique is used to extract the mode shape from measurements that continuously measure the vibration of a region of interest within a structure using a non-contact laser sensor. In previous research regarding the HHT, two technical processes were needed to obtain the mode shape for each mode. The purpose of this study is to improve and complement our previous research, and for this purpose, a modal analysis approach is adapted without using the two technical processes to obtain an accurate un-damped impulse response of each mode for continuous scanning measurements. In addition, frequency response functions for each type of beam are derived, making it possible to make continuously scanned measurements along a straight profile. In this paper, the technical limitations and drawbacks of the damping compensation technique used in previous research are identified. In addition, the separation of resonant frequency (the Doppler effect) that occurs in continuous scanning measurements and the separation of damping phenomenon are also observed. The proposed method is quantitatively verified by comparing it with the results obtained from a conventional approach to estimate the mode shape with an impulse response.

  18. Enhanced method to reconstruct mode shapes of continuous scanning measurements using the Hilbert Huang transform and the modal analysis method.

    PubMed

    Lee, Jongsuh; Hussain, Syed Hassaan; Wang, Semyung; Park, Kyihwan

    2014-09-01

    Generally, it is time consuming to experimentally identify the operating deflection shape or mode shape of a structure. To overcome this problem, the Hilbert Huang transform (HHT) technique has been recently proposed. This technique is used to extract the mode shape from measurements that continuously measure the vibration of a region of interest within a structure using a non-contact laser sensor. In previous research regarding the HHT, two technical processes were needed to obtain the mode shape for each mode. The purpose of this study is to improve and complement our previous research, and for this purpose, a modal analysis approach is adapted without using the two technical processes to obtain an accurate un-damped impulse response of each mode for continuous scanning measurements. In addition, frequency response functions for each type of beam are derived, making it possible to make continuously scanned measurements along a straight profile. In this paper, the technical limitations and drawbacks of the damping compensation technique used in previous research are identified. In addition, the separation of resonant frequency (the Doppler effect) that occurs in continuous scanning measurements and the separation of damping phenomenon are also observed. The proposed method is quantitatively verified by comparing it with the results obtained from a conventional approach to estimate the mode shape with an impulse response.

  19. General Boundary-Value Problems for the Heat Conduction Equation with Piecewise-Continuous Coefficients

    NASA Astrophysics Data System (ADS)

    Tatsii, R. M.; Pazen, O. Yu.

    2016-03-01

    A constructive scheme for the construction of a solution of a mixed problem for the heat conduction equation with piecewise-continuous coefficients coordinate-dependent in the final interval is suggested and validated in the present work. The boundary conditions are assumed to be most general. The scheme is based on: the reduction method, the concept of quasi-derivatives, the currently accepted theory of the systems of linear differential equations, the Fourier method, and the modified method of eigenfunctions. The method based on this scheme should be related to direct exact methods of solving mixed problems that do not employ the procedures of constructing Green's functions or integral transformations. Here the theorem of eigenfunction expansion is adapted for the case of coefficients that have discontinuity points of the 1st kind. The results obtained can be used, for example, in investigating the process of heat transfer in a multilayer slab under conditions of ideal thermal contact between the layers. A particular case of piecewise-continuous coefficients is considered. A numerical example of calculation of a temperature field in a real four-layer building slab under boundary conditions of the 3rd kind (conditions of convective heat transfer) that model the phenomenon of fire near one of the external surfaces is given.

  20. Default mode network activity in male adolescents with conduct and substance use disorder.

    PubMed

    Dalwani, Manish S; Tregellas, Jason R; Andrews-Hanna, Jessica R; Mikulich-Gilbertson, Susan K; Raymond, Kristen M; Banich, Marie T; Crowley, Thomas J; Sakai, Joseph T

    2014-01-01

    Adolescents with conduct disorder (CD) and substance use disorders (SUD) experience difficulty evaluating and regulating their behavior in anticipation of future consequences. Given the role of the brain's default mode network (DMN) in self-reflection and future thought, this study investigates whether DMN is altered in adolescents with CD and SUD, relative to controls. Twenty adolescent males with CD and SUD and 20 male controls of similar ages underwent functional magnetic resonance imaging as they completed a risk-taking decision task. We used independent component analysis as a data-driven approach to identify the DMN spatial component in individual subjects. DMN activity was then compared between groups. Compared to controls, patients showed reduced activity in superior, medial and middle frontal gyrus (Brodmann area (BA) 10), retrosplenial cortex (BA 30) and lingual gyrus (BA 18), and bilateral middle temporal gryus (BA 21/22) - DMN regions thought to support self-referential evaluation, memory, foresight, and perspective taking. Furthermore, this pattern of reduced activity in patients remained robust after adjusting for the effects of depression and attention-deficit hyperactivity disorder (ADHD). Conversely, when not adjusting for effects of depression and ADHD, patients demonstrated greater DMN activity than controls solely in the cuneus (BA 19). Collectively, these results suggest that comorbid CD and SUD in adolescents is characterized by atypical activity in brain regions thought to play an important role in introspective processing. These functional imbalances in brain networks may provide further insight into the neural underpinnings of conduct and substance use disorders. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  1. 14-W continuous-wave mode-locked Nd:YAG laser

    SciTech Connect

    De Silvestri, S.; Laporta, P.; Magni, V.

    1986-12-01

    A new design procedure for solid-state laser resonators operating in the fundamental mode is applied to the optimization of the mode volume and stability of a cw Nd:YAG laser. The optimized laser provides the highest power in the mode-locking regime reported to date.

  2. Observation of tearing mode deceleration and locking in MST due to eddy currents induced in the conducting shell

    NASA Astrophysics Data System (ADS)

    Chapman, B. E.; Craig, D.; Fitzpatrick, R.; Martin, P.; Spizzo, G.

    2003-10-01

    Growth to large amplitude of a single core-resonant tearing mode in the MST RFP is accompanied by braking and eventual cessation of the mode rotation. There is also a concurrent deceleration of the bulk plasma rotation. The mode deceleration is shown to be well described by a time-dependent version of a magnetohydrodynamical model [R. Fitzpatrick et al., Phys. Plasmas 6, 3878 (1999)] in which a braking torque originates from eddy currents induced by the rotating mode in the conducting shell surrounding the plasma. According to the model, the electromagnetic braking torque is localized to the plasma in the immediate vicinity of the mode's resonant surface, but viscosity transfers the torque to the rest of the plasma. Parametrizing the plasma momentum diffusivity in terms of the global momentum confinement time, and predicting the confinement time by fitting to the experimental braking data, the model predicts confinement times quite consistent with what is measured experimentally.

  3. Improved dichotomous search frequency offset estimator for burst-mode continuous phase modulation

    NASA Astrophysics Data System (ADS)

    Zhai, Wen-Chao; Li, Zan; Si, Jiang-Bo; Bai, Jun

    2015-11-01

    A data-aided technique for carrier frequency offset estimation with continuous phase modulation (CPM) in burst-mode transmission is presented. The proposed technique first exploits a special pilot sequence, or training sequence, to form a sinusoidal waveform. Then, an improved dichotomous search frequency offset estimator is introduced to determine the frequency offset using the sinusoid. Theoretical analysis and simulation results indicate that our estimator is noteworthy in the following aspects. First, the estimator can operate independently of timing recovery. Second, it has relatively low outlier, i.e., the minimum signal-to-noise ratio (SNR) required to guarantee estimation accuracy. Finally, the most important property is that our estimator is complexity-reduced compared to the existing dichotomous search methods: it eliminates the need for fast Fourier transform (FFT) and modulation removal, and exhibits faster convergence rate without accuracy degradation. Project supported by the National Natural Science Foundation of China (Grant No. 61301179), the Doctorial Programs Foundation of the Ministry of Education, China (Grant No. 20110203110011), and the Programme of Introducing Talents of Discipline to Universities, China (Grant No. B08038).

  4. Carotid wall stress calculated with continuous intima-media thickness assessment using B-mode ultrasound

    NASA Astrophysics Data System (ADS)

    Pascaner, A. F.; Craiem, D.; Casciaro, M. E.; Danielo, R.; Graf, S.; Guevara, E.

    2016-04-01

    Cardiovascular risk is normally assessed using clinical risk factors but it can be refined using non-invasive infra-clinical markers. Intima-Media Thickness (IMT) is recognized as an early indicator of cardiovascular disease. Carotid Wall Stress (CWS) can be calculated using arterial pressure and carotid size (diameter and IMT). Generally, IMT is measured during diastole when it reaches its maximum value. However, it changes during the cardiac cycle and a time-dependant waveform can be obtained using B-mode ultrasound images. In this work we calculated CWS considering three different approaches for IMT assessment: (i) constant IMT (standard diastolic value), (ii) estimated IMT from diameter waveform (assuming a constant cross-sectional wall area) and (iii) continuously measured IMT. Our results showed that maximum wall stress depends on the IMT estimation method. Systolic CWS progressively increased using the three approaches (p<0.024). We conclude that maximum CWS is highly dependent on wall thickness and accurate IMT measures during systole should be encouraged.

  5. Picosecond pulses from wavelength-swept continuous-wave Fourier domain mode-locked lasers.

    PubMed

    Eigenwillig, Christoph M; Wieser, Wolfgang; Todor, Sebastian; Biedermann, Benjamin R; Klein, Thomas; Jirauschek, Christian; Huber, Robert

    2013-01-01

    Ultrafast lasers have a crucial function in many fields of science; however, up to now, high-energy pulses directly from compact, efficient and low-power semiconductor lasers are not available. Therefore, we introduce a new approach based on temporal compression of the continuous-wave, wavelength-swept output of Fourier domain mode-locked lasers, where a narrowband optical filter is tuned synchronously to the round-trip time of light in a kilometre-long laser cavity. So far, these rapidly swept lasers enabled orders-of-magnitude speed increase in optical coherence tomography. Here we report on the generation of ~60-70 ps pulses at 390 kHz repetition rate. As energy is stored optically in the long-fibre delay line and not as population inversion in the laser-gain medium, high-energy pulses can now be generated directly from a low-power, compact semiconductor-based oscillator. Our theory predicts subpicosecond pulses with this new technique in the future.

  6. The continuous improvement of H-mode discharge performance with progressively increasing lithium coatings in NSTX

    NASA Astrophysics Data System (ADS)

    Maingi, R.; Kaye, S. M.; Skinner, C. H.; Boyle, D. P.; Canik, J. M.; NSTX Team

    2011-10-01

    Lithium wall coatings have been shown to reduce recycling, improve energy confinement,, and suppress edge localized modes, in the NSTX. Here we show that these effects depend nearly continuously on the amount of pre-discharge lithium evaporation. We observed a nearly monotonic reduction in recycling and a decrease in edge electron transport with increasing lithium. Moreover we see a reduction in the electron temperature and profile peaking factors, as well as an improvement in ELM stability with increasing lithium. These correlations challenge basic expectations, given that even the smallest coatings provided a nominal minimum lithium coating thickness of 30 nm, and an average of 60 nm near the outer divertor strike point; the maximum coating thickness was 8x higher. In comparison, the nominal implantation range, which is the relevant scale length for recycling and pumping, was < 10 nm. *Supported in part by U.S. DoE contracts DE-AC05-00OR22725 and DE-AC02-09CH11466.

  7. Formaldehyde degradation by UV/TiO2/O3 process using continuous flow mode.

    PubMed

    Qi, Hong; Sun, De-Zhi; Chi, Guo-Qing

    2007-01-01

    The degradation of formaldehyde gas was studied using UV/TiO2/O3 process under the condition of continuous flow mode. The effects of humidity, initial formaldehyde concentration, residence time and ozone adding amount on degradation of formaldehyde gas were investigated. The experimental results indicated that the combination of ozonation with photocatalytic oxidation on the degradation of formaldehyde showed a synergetic action, e.g., it could considerably increase decomposing of formaldehyde. The degradation efficiency of formaldehyde was between 73.6% and 79.4% while the initial concentration in the range of 1.84-24 mg/m3 by O3/TiO2/UV process. The optimal humidity was about 50% in UV/TiO2/O3 processs and degradation of formaldehyde increases from 39.0% to 94.1% when the ozone content increased from 0 to 141 mg/m3. Furthermore, the kinetics of formaldehyde degradation reaction could be described by Langmuir-Hinshelwood model. The rate constant k of 46.72 mg/(m3 x min) and Langmuir adsorption coefficient K of 0.0268 m3/mg were obtained.

  8. The structure of mode-locking regions of piecewise-linear continuous maps: I. Nearby mode-locking regions and shrinking points

    NASA Astrophysics Data System (ADS)

    Simpson, D. J. W.

    2017-01-01

    The mode-locking regions of a dynamical system are subsets of parameter space within which there exists an attracting periodic solution. For piecewise-linear continuous maps, these regions have a distinctive chain structure with points of zero width called shrinking points. In this paper a local analysis about an arbitrary shrinking point is performed. This is achieved by studying the symbolic itineraries of periodic solutions in nearby mode-locking regions and performing an asymptotic analysis on one-dimensional centre manifolds in order to build a comprehensive theoretical framework for the local dynamics. The main results are universal quantitative descriptions for the shape of nearby mode-locking regions, the location of nearby shrinking points, and the key properties of these shrinking points. The results are applied to the three-dimensional border-collision normal form, a model of an oscillator subject to dry friction, and a model of a DC/DC power converter.

  9. Ventilatory modes and mechanics of the hedgehog skate (Leucoraja erinacea): testing the continuous flow model.

    PubMed

    Summers, A P; Ferry-Graham, L A

    2001-05-01

    The movement of water across the gills of non-ram-ventilating fishes involves the action of two pumps: a pressure pump that pushes water across the gills from the oropharyngeal to the parabranchial cavity, and a suction pump that draws water across the gills from the oropharyngeal into the parabranchial cavity. Together, the two are thought to keep water flowing continuously anteroposteriorly through the head of the respiring animal. However, there is evidence that the pressure and suction pumps do not always work in perfect phase in elasmobranch fishes, leading to periods of higher pressure in the parabranchial than in the oropharyngeal cavity. We investigated the existence and consequence of such pressure reversals in the hedgehog skate Leucoraja erinacea using pressure transducers, sonomicrometry and flow visualization including internal visualization using endoscopy. We noted four patterns of respiration in the experimental skates distinguished by the flow pattern at the three openings into the respiratory system: (1) in through the spiracle only, (2) in through the mouth + spiracle, (3) in through the mouth only, and (4) the mouth held open throughout the respiratory cycle. The first two were by far the dominant modes recorded from experimental animals. We determined that pressure reversals exist in the hedgehog skate, and that the gill bars adducted during such pressure reversals. Direct observation confirmed that these pressure reversals do correspond to pulsatile flow across the gills. During mouth+spiracle ventilation the flow completely reversed direction, flowing from the parabranchial chambers back across the gills and into the oropharyngeal cavity. Finally, we addressed the utility of sonomicrometry as a technique for determining kinematics in aquatic animals. Despite some problems involving errors inherent to the system design, we found the technique useful for complementing such techniques as pressure measurements and endoscopy.

  10. Scale-up of BDD anode system for electrochemical oxidation of phenol simulated wastewater in continuous mode.

    PubMed

    Zhu, Xiuping; Ni, Jinren; Wei, Junjun; Xing, Xuan; Li, Hongna; Jiang, Yi

    2010-12-15

    Scale-up of boron-doped diamond (BDD) anode system is significant to the practical application of electrochemical oxidation in bio-refractory wastewater treatment. In this study, the performance of a smaller BDD anode (24 cm(2)) system in continuous mode electrochemical oxidation of phenol simulated wastewater was first investigated and well described by the response surface methodology (RSM). Furthermore, the RSM was extended to examine the scale-up feasibility of BDD anode systems with similar configurations. It was demonstrated that both COD degradation efficiency and specific energy consumption could be expected at the same level even as the system was enlarged over 100 times, which implied that BDD anode system could be successfully scaled up through controlling the same retention time, current density, initial COD, and conductivity conditions. Based on this study, a larger BDD anode (2904 cm(2)) system was constructed and systematic measurements were made on its performance in electrochemical oxidation of phenol simulated wastewater. Very good agreement was found between measured and predicted results by RSM. At the optimized conditions, the larger BDD anode system could easily reduce the COD of phenol simulated wastewater from 633 mg L(-1) to 145 mg L(-1) (<150 mg L(-1), National Discharge Standard of China) during 80 min with specific energy consumption only 31 kWh kgCOD(-1). Copyright © 2010 Elsevier B.V. All rights reserved.

  11. An effective sampling clock synchronization method for continuous- and burst-mode transmission in OFDMA-PONs

    NASA Astrophysics Data System (ADS)

    Cai, Yufeng; Zhang, Qianwu; Chen, Rongrong; Kuang, Caixia; Zhang, Zhen; Li, Yingchun; Chen, Jian

    2017-02-01

    A sampling frequency offset (SFO) estimation and compensation method based on frequency domain correlation of long training symbols for orthogonal frequency division multiple access passive optical network (OFDMA-PON) is experimentally demonstrated, which shows excellent performances in transmissions of continuous- and burst-mode. For continuous-mode transmission under a certain SFO, the proposed scheme can perform effectively in a wide received optical power (RoP) range from -8 dBm to -2 dBm and has high estimation veracity and a large applicable range as large as 100 ppm at a certain RoP. Similar behavior is also demonstrated under burst-mode transmission with tiny performance degradation caused by the fact that the algorithm needs time to reach a stable status of synchronization.

  12. Mixotrophic growth of Phaeodactylum tricornutum on fructose and glycerol in fed-batch and semi-continuous modes.

    PubMed

    Cerón-García, M C; Fernández-Sevilla, J M; Sánchez-Mirón, A; García-Camacho, F; Contreras-Gómez, A; Molina-Grima, E

    2013-11-01

    Mixotrophic cultures of Phaeodactylum tricornutum were carried out in bubble columns using fructose and glycerol in indoor fed-batch and semi-continuous modes. In the fed-batch cultures, different nutrient-addition strategies, combined with stepwise increments in the light intensity, were assayed. It was found that glycerol promoted significantly higher biomass productivity than fructose. A glycerol-induced photoinhibition that arrested the growth of P. tricornutun was also observed. As this was considered a limitation as regards transferring the fed-batch mode to outdoor conditions, this information was used to culture P. tricornutum in semi-continuous mode. Similar glycerol-induced photoinhibition was not observed in these cultures, even at highest dilution rates. Although the highest biomass (1.5 g L(-1) d(-1)) and EPA (40 mg L(-1) d(-1)) productivities found in the semi-continuous cultures were lower than those obtained photoautotrophically in outdoor photobioreactors, the findings showed that semi-continuous mode was an excellent candidate for transferring mixotrophic culture to an outdoor setting.

  13. A Latent Class Multidimensional Scaling Model for Two-Way One-Mode Continuous Rating Dissimilarity Data

    ERIC Educational Resources Information Center

    Vera, J. Fernando; Macias, Rodrigo; Heiser, Willem J.

    2009-01-01

    In this paper, we propose a cluster-MDS model for two-way one-mode continuous rating dissimilarity data. The model aims at partitioning the objects into classes and simultaneously representing the cluster centers in a low-dimensional space. Under the normal distribution assumption, a latent class model is developed in terms of the set of…

  14. Pervasive Modes of Thinking That Affect Our Conduct of Teaching, Supervision, and Research: Are We Stuck in an Old Paradigm?

    ERIC Educational Resources Information Center

    Krugman, Martin; Andrews, Sharon Vincz

    This paper identifies the major modes of thought that have characterized the conduct of teaching, research, and supervision at institutions of higher education, focusing specifically on the fields of psychology and education. These frameworks for thinking (paradigms) in both the social and "hard" sciences have progressed through three…

  15. Toward integrated multi-scale pedestal simulations including edge-localized-mode dynamics, evolution of edge-localized-mode cycles, and continuous fluctuations

    NASA Astrophysics Data System (ADS)

    Xu, X. Q.; Xia, T. Y.; Yan, N.; Liu, Z. X.; Kong, D. F.; Diallo, A.; Groebner, R. J.; Hubbard, A. E.; Hughes, J. W.

    2016-05-01

    The high-fidelity BOUT++ two-fluid code suite has demonstrated significant recent progress toward integrated multi-scale simulations of tokamak pedestal, including Edge-Localized-Mode (ELM) dynamics, evolution of ELM cycles, and continuous fluctuations, as observed in experiments. Nonlinear ELM simulations show three stages of an ELM event: (1) a linear growing phase; (2) a fast crash phase; and (3) a slow inward turbulence spreading phase lasting until the core heating flux balances the ELM energy loss and the ELM is terminated. A new coupling/splitting model has been developed to perform simulations of multi-scale ELM dynamics. Simulation tracks five ELM cycles for 10 000 Alfvén times for small ELMs. The temporal evolution of the pedestal pressure is similar to that of experimental measurements for the pedestal pressure profile collapses and recovers to a steep gradient during ELM cycles. To validate BOUT++ simulations against experimental data and develop physics understanding of the fluctuation characteristics for different tokamak operation regimes, both quasi-coherent fluctuations (QCFs) in ELMy H-modes and Weakly Coherent Modes in I-modes have been simulated using three dimensional 6-field 2-fluid electromagnetic model. The H-mode simulation results show that (1) QCFs are localized in the pedestal region having a predominant frequency at f ≃300 -400 kHz and poloidal wavenumber at kθ≃0.7 cm-1 , and propagate in the electron diamagnetic direction in the laboratory frame. The overall signatures of simulation results for QCFs show good agreement with C-Mod and DIII-D measurements. (2) The pedestal profiles giving rise to QCFs are near the marginal instability threshold for ideal peeling-ballooning modes for both C-Mod and DIII-D, while the collisional electromagnetic drift-Alfvén wave appears to be dominant for DIII-D. (3) Particle diffusivity is either smaller than the heat diffusivity for DIII-D or similar to the heat diffusivity for C-Mod. Key I-mode

  16. Modes of high-latitude auroral conductance variability derived from DMSP energetic electron precipitation observations: Empirical orthogonal function analysis

    NASA Astrophysics Data System (ADS)

    McGranaghan, Ryan; Knipp, Delores J.; Matsuo, Tomoko; Godinez, Humberto; Redmon, Robert J.; Solomon, Stanley C.; Morley, Steven K.

    2015-12-01

    We provide the first ever characterization of the primary modes of ionospheric Hall and Pedersen conductance variability as empirical orthogonal functions (EOFs). These are derived from six satellite years of Defense Meteorological Satellite Program (DMSP) particle data acquired during the rise of solar cycles 22 and 24. The 60 million DMSP spectra were each processed through the Global Airlglow Model. Ours is the first large-scale analysis of ionospheric conductances completely free of assumption of the incident electron energy spectra. We show that the mean patterns and first four EOFs capture ˜50.1 and 52.9% of the total Pedersen and Hall conductance variabilities, respectively. The mean patterns and first EOFs are consistent with typical diffuse auroral oval structures and quiet time strengthening/weakening of the mean pattern. The second and third EOFs show major disturbance features of magnetosphere-ionosphere (MI) interactions: geomagnetically induced auroral zone expansion in EOF2 and the auroral substorm current wedge in EOF3. The fourth EOFs suggest diminished conductance associated with ionospheric substorm recovery mode. We identify the most important modes of ionospheric conductance variability. Our results will allow improved modeling of the background error covariance needed for ionospheric assimilative procedures and improved understanding of MI coupling processes.

  17. Elastic flexibility, fast-ion conduction, boson and floppy modes in AgPO(3)-AgI glasses.

    PubMed

    Novita, Deassy I; Boolchand, P; Malki, M; Micoulaut, Matthieu

    2009-05-20

    Raman scattering, IR reflectance and modulated-DSC measurements are performed on specifically prepared dry (AgI)(x)(AgPO(3))(1-x) glasses over a wide range of compositions 0%37.8% are elastically flexible. Raman optical elasticity power laws, trends in the nature of the glass transition endotherms, corroborate the three elastic phase assignments. Ionic conductivities reveal a step-like increase when glasses become stress-free at x>x(c)(1) = 9.5% and a logarithmic increase in conductivity (σ∼(x-x(c)(2))(μ)) once they become flexible at x>x(c)(2) = 37.8% with a power law μ = 1.78. The power law is consistent with percolation of 3D filamentary conduction pathways. Traces of water doping lower T(g) and narrow the reversibility window, and can also completely collapse it. Ideas on network flexibility promoting ion conduction are in harmony with the unified approach of Ingram et al (2008 J. Phys. Chem. B 112 859), who have emphasized the similarity of process compliance or elasticity relating to ion transport and structural relaxation in decoupled systems. Boson mode frequency and scattering strength display thresholds that coincide with the two elastic phase boundaries. In particular, the scattering strength of the boson mode increases almost linearly with glass composition x, with a slope that tracks the floppy mode fraction as a function of mean coordination number r predicted by mean-field rigidity theory. These data suggest that the excess low frequency vibrations contributing to the boson mode in flexible glasses come largely from floppy modes.

  18. Multipartite entanglement in three-mode Gaussian states of continuous-variable systems: Quantification, sharing structure, and decoherence

    NASA Astrophysics Data System (ADS)

    Adesso, Gerardo; Serafini, Alessio; Illuminati, Fabrizio

    2006-03-01

    We present a complete analysis of the multipartite entanglement of three-mode Gaussian states of continuous-variable systems. We derive standard forms which characterize the covariance matrix of pure and mixed three-mode Gaussian states up to local unitary operations, showing that the local entropies of pure Gaussian states are bound to fulfill a relationship which is stricter than the general Araki-Lieb inequality. Quantum correlations can be quantified by a proper convex roof extension of the squared logarithmic negativity, the continuous-variable tangle, or contangle. We review and elucidate in detail the proof that in multimode Gaussian states the contangle satisfies a monogamy inequality constraint [G. Adesso and F. Illuminati, New J. Phys8, 15 (2006)]. The residual contangle, emerging from the monogamy inequality, is an entanglement monotone under Gaussian local operations and classical communications and defines a measure of genuine tripartite entanglements. We determine the analytical expression of the residual contangle for arbitrary pure three-mode Gaussian states and study in detail the distribution of quantum correlations in such states. This analysis yields that pure, symmetric states allow for a promiscuous entanglement sharing, having both maximum tripartite entanglement and maximum couplewise entanglement between any pair of modes. We thus name these states GHZ/W states of continuous-variable systems because they are simultaneous continuous-variable counterparts of both the GHZ and the W states of three qubits. We finally consider the effect of decoherence on three-mode Gaussian states, studying the decay of the residual contangle. The GHZ/W states are shown to be maximally robust against losses and thermal noise.

  19. Multipartite entanglement in three-mode Gaussian states of continuous-variable systems: Quantification, sharing structure, and decoherence

    SciTech Connect

    Adesso, Gerardo; Serafini, Alessio; Illuminati, Fabrizio

    2006-03-15

    We present a complete analysis of the multipartite entanglement of three-mode Gaussian states of continuous-variable systems. We derive standard forms which characterize the covariance matrix of pure and mixed three-mode Gaussian states up to local unitary operations, showing that the local entropies of pure Gaussian states are bound to fulfill a relationship which is stricter than the general Araki-Lieb inequality. Quantum correlations can be quantified by a proper convex roof extension of the squared logarithmic negativity, the continuous-variable tangle, or contangle. We review and elucidate in detail the proof that in multimode Gaussian states the contangle satisfies a monogamy inequality constraint [G. Adesso and F. Illuminati, New J. Phys8, 15 (2006)]. The residual contangle, emerging from the monogamy inequality, is an entanglement monotone under Gaussian local operations and classical communications and defines a measure of genuine tripartite entanglements. We determine the analytical expression of the residual contangle for arbitrary pure three-mode Gaussian states and study in detail the distribution of quantum correlations in such states. This analysis yields that pure, symmetric states allow for a promiscuous entanglement sharing, having both maximum tripartite entanglement and maximum couplewise entanglement between any pair of modes. We thus name these states GHZ/W states of continuous-variable systems because they are simultaneous continuous-variable counterparts of both the GHZ and the W states of three qubits. We finally consider the effect of decoherence on three-mode Gaussian states, studying the decay of the residual contangle. The GHZ/W states are shown to be maximally robust against losses and thermal noise.

  20. High-efficiency multipass Ti:sapphire amplifiers for a continuous-wave single-mode laser.

    PubMed

    Georges, P; Estable, F; Salin, F; Poizat, J P; Grangier, P; Brun, A

    1991-02-01

    We present the amplification of a continuous-wave single-mode ring dye laser in Ti:sapphire. A peak gain of 2 x 10(6) has been obtained in a passive multipass amplifier, which yielded 20-nsec pulses of 0.7-mJ energy at 780 nm. We discuss the advantages of this passive multipass amplifier in comparison with a regenerative amplifier that we have also developed. By second-harmonic generation we obtained high-peak-power UV pulses from the amplified single-mode laser.

  1. A One Year Study of Mode Deactivation Therapy: Adolescent Residential Patients with Conduct and Personality Disorders

    ERIC Educational Resources Information Center

    Murphy, Christopher J.; Siv, Alexander M.

    2007-01-01

    This case study is to evaluate the effectiveness of Mode Deactivation Therapy (MDT) implementation in a child and adolescent residential treatment unit and provide preliminary effectiveness data on MDT versus treatment as usual (TAU). This case study compared the efficacy of two treatment methodologies for adolescent males in residential treatment…

  2. A One Year Study of Mode Deactivation Therapy: Adolescent Residential Patients with Conduct and Personality Disorders

    ERIC Educational Resources Information Center

    Murphy, Christopher J.; Siv, Alexander M.

    2011-01-01

    This case study is to evaluate the effectiveness of Mode Deactivation Therapy (MDT) implementation in a child and adolescent residential treatment unit and provide preliminary effectiveness data on MDT versus treatment as usual (TAU). This case study compared the efficacy of two treatment methodologies for adolescent males in residential treatment…

  3. How I Learned to Design and Conduct Semi-Structured Interviews: An Ongoing and Continuous Journey

    ERIC Educational Resources Information Center

    Rabionet, Silvia E.

    2011-01-01

    Qualitative interviewing is a flexible and powerful tool to capture the voices and the ways people make meaning of their experience Learning to conduct semi-structure interviews requires the following six stages: (a) selecting the type of interview; (b) establishing ethical guidelines, (c) crafting the interview protocol; (d) conducting and…

  4. Thermal conductivity measurements of high and low thermal conductivity films using a scanning hot probe method in the 3ω mode and novel calibration strategies.

    PubMed

    Wilson, Adam A; Muñoz Rojo, Miguel; Abad, Begoña; Perez, Jaime Andrés; Maiz, Jon; Schomacker, Jason; Martín-Gonzalez, Marisol; Borca-Tasciuc, Diana-Andra; Borca-Tasciuc, Theodorian

    2015-10-07

    This work discusses measurement of thermal conductivity (k) of films using a scanning hot probe method in the 3ω mode and investigates the calibration of thermal contact parameters, specifically the thermal contact resistance (R(th)C) and thermal exchange radius (b) using reference samples with different thermal conductivities. R(th)C and b were found to have constant values (with b = 2.8 ± 0.3 μm and R(th)C = 44,927 ± 7820 K W(-1)) for samples with thermal conductivity values ranging from 0.36 W K(-1) m(-1) to 1.1 W K(-1) m(-1). An independent strategy for the calibration of contact parameters was developed and validated for samples in this range of thermal conductivity, using a reference sample with a previously measured Seebeck coefficient and thermal conductivity. The results were found to agree with the calibration performed using multiple samples of known thermal conductivity between 0.36 and 1.1 W K(-1) m(-1). However, for samples in the range between 16.2 W K(-1) m(-1) and 53.7 W K(-1) m(-1), calibration experiments showed the contact parameters to have considerably different values: R(th)C = 40,191 ± 1532 K W(-1) and b = 428 ± 24 nm. Finally, this work demonstrates that using these calibration procedures, measurements of both highly conductive and thermally insulating films on substrates can be performed, as the measured values obtained were within 1-20% (for low k) and 5-31% (for high k) of independent measurements and/or literature reports. Thermal conductivity results are presented for a SiGe film on a glass substrate, Te film on a glass substrate, polymer films (doped with Fe nano-particles and undoped) on a glass substrate, and Au film on a Si substrate.

  5. Continuous glucose monitoring microsensor with a nanoscale conducting matrix and redox mediator

    NASA Astrophysics Data System (ADS)

    Pesantez, Daniel

    The major limiting factor in kidney clinical transplantation is the shortage of transplantable organs. The current inability to distinguish viability from non-viability on a prospective basis represents a major obstacle in any attempt to expand organ donor criteria. Consequently, a way to measure and monitor a relevant analyte to assess kidney viability is needed. For the first time, the initial development and characterization of a metabolic microsensor to assess kidney viability is presented. The rate of glucose consumption appears to serve as an indicator of kidney metabolism that may distinguish reversible from irreversible kidney damage. The proposed MetaSense (Metabolic Sensor) microdevice would replace periodic laboratory diagnosis tests with a continuous monitor that provides real-time data on organ viability. Amperometry, a technique that correlates an electrical signal with analyte concentration, is used as a method to detect glucose concentrations. A novel two-electrode electrochemical sensing cell design is presented. It uses a modified metallic working electrode (WE) and a bare metallic reference electrode (RE) that acts as a pseudo-reference/counter electrode as well. The proposed microsensor has the potential to be used as a minimally invasive sensor for its reduced number of probes and very small dimensions achieved by micromachining and lithography. In order to improve selectivity of the microdevice, two electron transfer mechanisms or generations were explored. A first generation microsensor uses molecular oxygen as the electron acceptor in the enzymatic reaction and oxidizes hydrogen peroxide (H2O2) to get the electrical signal. The microsensor's modified WE with conductive polymer polypyrrole (PPy) and corresponding enzyme glucose oxidase (GOx) immobilized into its matrix, constitutes the electrochemical detection mechanism. Photoluminescence spectroscopic analysis confirmed and quantified enzyme immobilized concentrations within the matrix. In

  6. Continuous-variable entanglement and two-mode squeezing in a single-atom Raman laser

    NASA Astrophysics Data System (ADS)

    Sete, Eyob A.; Ooi, C. H. Raymond

    2012-06-01

    The quantum statistical properties of light emitted by a two-photon double Raman laser is investigated. Using the master equation derived in the good-cavity limit, we study the squeezing and entanglement properties of the cavity field. It turns out that the cavity radiation exhibits two-mode squeezing and entanglement in the transient as well as steady state regime for realizable parameters. We establish a connection between two-mode squeezing and entanglement that gives insight into the physical origin of these quantum features. We also discuss the interplay between the laser detuning and amplitude in modifying the properties of the cavity field.

  7. Continuous sheathless microparticle and cell patterning using CL-SSAWs (conductive liquid-based standing surface acoustic waves)

    NASA Astrophysics Data System (ADS)

    Nam, Jeonghun; Kim, Jae Young; Lim, Chae Seung

    2017-01-01

    We present continuous, sheathless microparticle patterning using conductive liquid (CL)-based standing surface acoustic waves (SSAWs). Conventional metal electrodes patterned on a piezoelectric substrate were replaced with electrode channels filled with a CL. The device performance was evaluated with 5-μm fluorescent polystyrene particles at different flow rate and via phase shifting. In addition, our device was further applied to continuous concentration of malaria parasites at the sidewalls of the fluidic channel.

  8. Influence of Secondary Cooling Mode on Solidification Structure and Macro-segregation Behavior for High-carbon Continuous Casting Bloom

    NASA Astrophysics Data System (ADS)

    Dou, Kun; Yang, Zhenguo; Liu, Qing; Huang, Yunhua; Dong, Hongbiao

    2017-07-01

    A cellular automaton-finite element coupling model for high-carbon continuously cast bloom of GCr15 steel is established to simulate the solidification structure and to investigate the influence of different secondary cooling modes on characteristic parameters such as equiaxed crystal ratio, grain size and secondary dendrite arm spacing, in which the effect of phase transformation and electromagnetic stirring is taken into consideration. On this basis, evolution of carbon macro-segregation for GCr15 steel bloom is researched correspondingly via industrial tests. Based on above analysis, the relationship among secondary cooling modes, characteristic parameters for solidification structure as well as carbon macro-segregation is illustrated to obtain optimum secondary cooling strategy and alleviate carbon macro-segregation degree for GCr15 steel bloom in continuous casting process. The evaluating method for element macro-segregation is applicable in various steel types.

  9. High-power terahertz quantum cascade lasers with ∼0.23 W in continuous wave mode

    SciTech Connect

    Wang, Xuemin; Shen, Changle; Jiang, Tao; Zhan, Zhiqiang; Deng, Qinghua; Li, Weihua; Wu, Weidong; Yang, Ning; Chu, Weidong; Duan, Suqing

    2016-07-15

    Terahertz quantum cascade lasers with a record output power up to ∼0.23 W in continuous wave mode were obtained. We show that the optimal 2.9-mm-long device operating at 3.11 THz has a low threshold current density of 270 A/cm{sup 2} at ∼15 K. The maximum operating temperature arrived at ∼65 K in continuous wave mode and the internal quantum efficiencies decreased from 0.53 to 0.19 for the devices with different cavity lengths. By using one convex lens with the effective focal length of 13 mm, the beam profile was collimated to be a quasi Gaussian distribution.

  10. High-power terahertz quantum cascade lasers with ˜0.23 W in continuous wave mode

    NASA Astrophysics Data System (ADS)

    Wang, Xuemin; Shen, Changle; Jiang, Tao; Zhan, Zhiqiang; Deng, Qinghua; Li, Weihua; Wu, Weidong; Yang, Ning; Chu, Weidong; Duan, Suqing

    2016-07-01

    Terahertz quantum cascade lasers with a record output power up to ˜0.23 W in continuous wave mode were obtained. We show that the optimal 2.9-mm-long device operating at 3.11 THz has a low threshold current density of 270 A/cm2 at ˜15 K. The maximum operating temperature arrived at ˜65 K in continuous wave mode and the internal quantum efficiencies decreased from 0.53 to 0.19 for the devices with different cavity lengths. By using one convex lens with the effective focal length of 13 mm, the beam profile was collimated to be a quasi Gaussian distribution.

  11. Continuous-variable quantum cloning of coherent states with phase-conjugate input modes using linear optics

    SciTech Connect

    Chen, Haixia; Zhang, Jing

    2007-02-15

    We propose a scheme for continuous-variable quantum cloning of coherent states with phase-conjugate input modes using linear optics. The quantum cloning machine yields M identical optimal clones from N replicas of a coherent state and N replicas of its phase conjugate. This scheme can be straightforwardly implemented with the setups accessible at present since its optical implementation only employs simple linear optical elements and homodyne detection. Compared with the original scheme for continuous-variable quantum cloning with phase-conjugate input modes proposed by Cerf and Iblisdir [Phys. Rev. Lett. 87, 247903 (2001)], which utilized a nondegenerate optical parametric amplifier, our scheme loses the output of phase-conjugate clones and is regarded as irreversible quantum cloning.

  12. Suppression of continuous lasing in a carbon nanotube polyimide film mode-locked erbium-doped fiber laser.

    PubMed

    Gui, Lili; Yang, Xin; Zhao, Guangzhen; Yang, Xu; Xiao, Xiaosheng; Zhu, Jinsong; Yang, Changxi

    2011-01-01

    We demonstrated an erbium-doped mode-locked fiber laser using a single-walled carbon nanotube-dispersed polyimide (SWNT-PI) film. Different mode-locking operations were compared and analyzed utilizing SWNT-PI films with different concentrations (2, 1, and 0.25 wt.%, respectively). It was found that the continuous single-pulse mode-locking operation was often accompanied by a continuous wave oscillation part for the 1 and 0.25 wt.% SWNT-PI films, whereas the 2 wt.% SWNT-PI film presented the most excellent mode-locking performance, thanks to sufficient modulation depth. Using the 2 wt.% SWNT-PI film, a stable pulse train with a pulse width of 840 fs and a repetition rate of 15.3 MHz was achieved. The average output power was 0.33 mW at the pump power of 155 mW under an output coupling ratio of 10%. Operational performance of the laser cavity when employing the 2 wt.% SWNT-PI film was also demonstrated.

  13. Non-destructive label-free continuous monitoring of in vitro chondrogenesis via electrical conductivity and its anisotropy.

    PubMed

    Oh, Tong In; Kim, Changhwan; Karki, Bishal; Son, Youngsook; Lee, EunAh; Woo, Eung Je

    2015-02-01

    Non-destructive label-free continuous monitoring of in vitro tissue culture is an unmet demand in tissue engineering. Noting that different compositions of cartilage lead to different electrical tissue properties, we propose a new method to measure the electrical conductivity and its anisotropy during in vitro chondrogenesis. We used a conductivity tensor probe with 17 electrodes and a bio-impedance spectroscopy (BIS) device to measure the conductivity values and the anisotropy ratios at the bottom and top surfaces of the tissue samples during the culture period of 6 weeks. Clearly distinguishing glycosaminoglycans (GAGs), collagen, and also various mixtures of them, the measured conductivity value and the estimated tissue anisotropy provide diagnostic information of the depth-dependent tissue structure and compositions. Continuously monitoring the individual tissue during the entire chondrogenesis process without any adverse effect, the proposed method may significantly increase the productivity of cartilage tissue engineering. © 2014 Wiley Periodicals, Inc.

  14. Effects of Ionospheric Reflection Height and Ground Conductivity on Earth-Ionosphere Waveguide Mode and Ground-Wave Attenuation Rates.

    DTIC Science & Technology

    1980-06-01

    except that for the diffraction model the free-space region is infinite. It can be shown ( Budden 9 ) that, for certain complex angles of wave normals...minimum possible signal may be incorrect for certain combinations of radio frequency., ground conductivity, and ionospheric height. 9- Budden , K.G...VLF Radio Waves, US Dept of Commerce, National Bureau of Standards, Technical Note 300. 9. Budden , K.G., The Waveguide Mode Theory of Wave Propagation

  15. Soft phonon modes driven reduced thermal conductivity in self-compensated Sn1.03Te with Mn doping

    NASA Astrophysics Data System (ADS)

    Acharya, Somnath; Pandey, Juhi; Soni, Ajay

    2016-09-01

    The key challenge for superior thermoelectric performance of SnTe is optimization of very high hole concentration (˜1021 cm-3) arising from inherent Sn vacancies. Partial control of charge carriers can be achieved by self-compensation via careful filling of the vacancies using excess Sn, although high thermal conductivity remained a concern. In this context, with deliberate doping, an anharmonicity in phonon dispersion can be generated to obtain a poor thermal conductivity. We report on point defects and soft phonon mode driven poor thermal conductivity in self-compensated Sn1.03Te with Mn doping. The obvious modification in the electronic band structure has been demonstrated by four times enhancement in thermopower for Sn0.93Mn0.1Te from Sn1.03Te, and metallic behavior of temperature dependent resistivity. The observed soft phonon mode and impurity localized mode in Raman spectra have been explained based on the created anharmonicity in Sn1.03Te crystal with Mn doping.

  16. Influence of water conductivity on particular electrospray modes with dc corona discharge — optical visualization approach

    NASA Astrophysics Data System (ADS)

    Pongrác, Branislav; Kim, Hyun-Ha; Negishi, Nobuaki; Machala, Zdenko

    2014-08-01

    The effect of water conductivity on electrospraying of water was studied in combination with positive DC corona discharge generated in air. We used a point-to-plane geometry of electrodes with a hollow syringe needle anode opposite to the metal mesh cathode. We employed total average current measurements and high-speed camera fast time-resolved imaging. We visualized the formation of a water jet (filament) and investigated corona discharge behavior for various water conductivities. Depending on the conductivity, various jet properties were observed: pointy, prolonged, and fast spreading water filaments for lower conductivity; in contrast to rounder, broader, and shorter quickly disintegrating filaments for higher conductivity. The large acceleration values (4060 m/s2 and 520 m/s2 for 2 μS/cm and 400 μS/cm, respectively) indicate that the process is mainly governed by the electrostatic force. In addition, with increasing conductivity, the breakdown voltage for corona-to-spark transition was decreasing.

  17. Dual-Mode Combustion of Hydrogen in a Mach 5, Continuous-Flow Facility

    NASA Technical Reports Server (NTRS)

    Goyne, C. P.; McDaniel, J. C.; Quagliaroli, T. M.; Krauss, R. H.; Day, S. W.; Reubush, D. E. (Technical Monitor); McClinton, C. R. (Technical Monitor); Reubush, D. E.

    2001-01-01

    Results of an experimental and numerical study of a dual-mode scramjet combustor are reported. The experiment consisted of a direct-connect test of a Mach 2 hydrogen-air combustor with a single unswept-ramp fuel injector. The flow stagnation enthalpy simulated a flight Mach number of 5. Measurements were obtained using conventional wall instrumentation and a particle-imaging laser diagnostic technique. The particle imaging was enabled through the development of a new apparatus for seeding fine silicon dioxide particles into the combustor fuel stream. Numerical simulations of the combustor were performed using the GASP code. The modeling, and much of the experimental work, focused on the supersonic combustion mode. Reasonable agreement was observed between experimental and numerical wall pressure distributions. However, the numerical model was unable to predict accurately the effects of combustion on the fuel plume size, penetration, shape, and axial growth.

  18. Continuous quantitative local cerebral blood flow measurement. Calibration of thermal conductivity measurements by the hydrogen clearance method.

    PubMed

    Cusick, J F; Myklebust, J

    1980-01-01

    The capability of a miniaturized probe to measure local cerebral blood flow in a continuous and quantitative manner is described. The incorporation of thermal conductivity measurements using the isothermal principle with the hydrogen clearance method allows calibration of the thermal conductivity component in absolute terms. Evaluation of this system in 14 cats showed a linear relationship between both measurement methods. The major limitation of this combination probe system is the need for routine intermittent recalibration in order that changes of tissues thermal conductivity induced by physiologic alterations during the experimental procedure may be recognized and resolved.

  19. Identification of Small Inhomogeneities of Extreme Conductivity by Boundary Measurements: A Continuous Dependence Result.

    DTIC Science & Technology

    1987-12-01

    location of the inhomogeneities and their geometry. Secondly we use this repr""’ntatien formula to prove a Lipschitz c,,t ,,¢us dcpcoidence estimate...A. Pericak-Spector, S. J. Spector, Nonuniqueness for a Hyperbolic System: Cavitation in Nonlinear Elastodynamics 306 E. G. Kalnins, W. Miller, Jr., q...Saturated Porous Media: Lipschitz Continuity of the Interface 336 B. J. Lucier, Regularity Through Approximation for Scalar Conservation Laws 337 B

  20. USING CONTINUOUS MONITORS FOR CONDUCTING TRACER STUDIES IN WATER DISTRIBUTION SYSTEMS

    EPA Science Inventory

    The use of online monitors for conducting a distribution system tracer study is proving to be an essential tool to accurately understand the flow dynamics in a distribution system. In a series of field testing sponsored by U. S. Environmental Protection Agency (EPA) and Greater ...

  1. USING CONTINUOUS MONITORS FOR CONDUCTING TRACER STUDIES IN WATER DISTRIBUTION SYSTEMS

    EPA Science Inventory

    The use of online monitors for conducting a distribution system tracer study is proving to be an essential tool to accurately understand the flow dynamics in a distribution system. In a series of field testing sponsored by U. S. Environmental Protection Agency (EPA) and Greater ...

  2. 20 CFR 416.989a - We may conduct a review to find out whether you continue to be blind.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... SUPPLEMENTAL SECURITY INCOME FOR THE AGED, BLIND, AND DISABLED Determining Disability and Blindness Continuing Or Stopping Disability Or Blindness § 416.989a We may conduct a review to find out whether you... time to determine if you are still eligible for payments based on blindness. We call this evaluation a...

  3. 20 CFR 416.989a - We may conduct a review to find out whether you continue to be blind.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... SUPPLEMENTAL SECURITY INCOME FOR THE AGED, BLIND, AND DISABLED Determining Disability and Blindness Continuing Or Stopping Disability Or Blindness § 416.989a We may conduct a review to find out whether you... time to determine if you are still eligible for payments based on blindness. We call this evaluation a...

  4. 20 CFR 416.989a - We may conduct a review to find out whether you continue to be blind.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... SUPPLEMENTAL SECURITY INCOME FOR THE AGED, BLIND, AND DISABLED Determining Disability and Blindness Continuing Or Stopping Disability Or Blindness § 416.989a We may conduct a review to find out whether you... time to determine if you are still eligible for payments based on blindness. We call this evaluation a...

  5. 20 CFR 416.989a - We may conduct a review to find out whether you continue to be blind.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... SUPPLEMENTAL SECURITY INCOME FOR THE AGED, BLIND, AND DISABLED Determining Disability and Blindness Continuing Or Stopping Disability Or Blindness § 416.989a We may conduct a review to find out whether you... time to determine if you are still eligible for payments based on blindness. We call this evaluation a...

  6. 20 CFR 416.989a - We may conduct a review to find out whether you continue to be blind.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... SUPPLEMENTAL SECURITY INCOME FOR THE AGED, BLIND, AND DISABLED Determining Disability and Blindness Continuing Or Stopping Disability Or Blindness § 416.989a We may conduct a review to find out whether you... time to determine if you are still eligible for payments based on blindness. We call this evaluation a...

  7. A continuous-discrete approach for evaluation of natural frequencies and mode shapes of high-rise buildings

    NASA Astrophysics Data System (ADS)

    Malekinejad, Mohsen; Rahgozar, Reza; Malekinejad, Ali; Rahgozar, Peyman

    2016-09-01

    In this paper, a continuous-discrete approach based on the concept of lumped mass and equivalent continuous approach is proposed for free vibration analysis of combined system of framed tube, shear core and outrigger-belt truss in high-rise buildings. This system is treated as a continuous system (i.e., discrete beams and columns are replaced with equivalent continuous membranes) and a discrete system (or lumped mass system) at different stages of dynamic analysis. The structure is discretized at each floor of the building as a series of lumped masses placed at the center of shear core. Each mass has two transitional degrees of freedom (lateral and axial( and one rotational. The effect of shear core and outrigger-belt truss on framed tube system is modeled as a rotational spring placed at the location of outrigger-belt truss system along structure's height. By solving the resulting eigen problem, natural frequencies and mode-shapes are obtained. Numerical examples are presented to show acceptable accuracy of the procedure in estimating the fundamental frequencies and corresponding mode shapes of the combined system as compared to finite element analysis of the complete structure. The simplified proposed method is much faster and should be more suitable for rapid interactive design.

  8. Non-physiological increase of AV conduction time in sinus disease patients programmed in AAIR-based pacing mode.

    PubMed

    Mabo, Philippe; Cebron, Jean-Pierre; Solnon, Aude; Tassin, Aude; Graindorge, Laurence; Gras, Daniel

    2012-11-01

    The EVOCAV(DS) trial aimed to quantify the paradoxal atrioventricular (AV) conduction time lengthening in sinus node (SD) patients (pts) paced in AAIR-based pacing mode. SD pts, implanted with dual-chamber pacemaker programmed in AAIR-based pacing mode, were randomized in two arms for a 1-month period: the low atrial pacing (LAP; basic rate at 60 bpm, dual sensor with minimal slope) and the high atrial pacing (HAP; basic rate at 70 bpm, dual sensor with optimized slope, overdrive pacing) arm. At 1 month, crossover was performed for an additional 1-month period. AV conduction time, AV block occurrence and AV conduction time adaptation during exercise were ascertained from device memories at each follow-up. Seventy-nine pts participated to the analysis (75 ± 8 years; 32 male; PR = 184 ± 38 ms; bundle branch block n = 12; AF history n = 36; antiarrhythmic treatment n = 53; beta-blockers n = 27; class III/Ic n = 18; both n = 8). The mean AV conduction time was significantly greater during the HAP (275 ± 51 ms) vs. LAP (263 ± 49 ms) period (p < 0.0001). Class III/Ic drugs were the only predictors of this abnormal behaviour. Degree II/III AV blocks occurred in 49 % of pts in the HAP vs. 19 % in the LAP period (p < 0.0001). Fifty-two patients (66 %) presented a lengthening of AV conduction time during exercise. AAIR-based pacing in SD pts may induce a significant lengthening of pts' AV conduction time, including frequent abnormal adaptation of AV conduction time during exercise.

  9. Application for continuation of mixed ionic and electronic conductivity in polymers

    SciTech Connect

    Shiver, D.F.; Ratner, M.A.

    1990-01-01

    The aim in this portion of the research is to prepare new electroactive films with high ion mobility, and to characterize the transport properties of these materials. The classic conducting polymers, polyacetylene, polythiophene, and polypyrrole have dense structures that prevent rapid redox switching because of the low diffusivity of ions. The objective is to modify the last two polymers with pendant polyethers, which should greatly improve ion transport.

  10. Entanglement transfer from two-mode anti-correlated continuous-variable systems to a pair of localized discrete systems

    NASA Astrophysics Data System (ADS)

    Ran, Du; Yang, Zhen-Biao

    2016-04-01

    We address the entanglement transfer from a bipartite continuous-variable(CV) system to a pair of localized discrete systems. The dynamics behavior can be implemented by two two-level atoms flying through spatially separated identical cavities where two quantized modes are injected. We assume each CV mode couples to one atom via the resonant Jaynes-Cummings interaction. The CV systems are initially prepared in a two-mode anti-correlated SU(2) coherent state, while with the initial atomic states of the cases: |g⟩1|g⟩2, |e⟩1|e⟩2 and |g⟩1|e⟩2, respectively. We find that the entanglement transfer for single-photon excitation case is more efficient than that for multi-photon excitation case. Under same conditions, we also note that the entanglement transfer is more efficient for SU(2) coherent state than for twin-bean (TWB) and pair-coherent (TMC) state. Besides, we show that, for a given total photon number of the initial SU(2) coherent state, the efficiency of entanglement transfer depends upon the distribution of photons in the two CV modes. We also consider the influences of the dissipation and the white noise on the entanglement transfer.

  11. The role of molar conductivity in electrospray cone-jet mode current scaling

    NASA Astrophysics Data System (ADS)

    Smith, Katharine L.; Alexander, Matthew S.; Stark, John P. W.

    2006-07-01

    A high accuracy online flow rate measurement system has been used to determine the current flow rate scaling relationships for solutions of organic solvents doped with sodium iodide and for the ionic liquid 1-ethyl-3-methyl imidazolium tetrafluoroborate over a range of conductivities from 0.0025-1.3S/m. The current flow rate trends for these solutions were found to exhibit a power law relationship similar to that described by previous researchers, where I (the electrospray current) is proportional to Q (the volumetric flow rate) to some power n. However, the exponent n of the current flow rate trends was found to differ from the theoretical predictions reported in the literature. A study including data from literature revealed the exponent of the current flow rate trends to be sensitive to the molar conductivity of the sprayed solution.

  12. Destruction of commercial pesticides by cerium redox couple mediated electrochemical oxidation process in continuous feed mode.

    PubMed

    Balaji, Subramanian; Chung, Sang Joon; Ryu, Jae-Yong; Moon, Il Shik

    2009-12-30

    Mediated electrochemical oxidation was carried out for the destruction of commercial pesticide formulations using cerium(IV) in nitric acid as the mediator electrolyte solution in a bench scale set up. The mediator oxidant was regenerated in situ using an electrochemical cell. The real application of this sustainable process for toxic organic pollutant destruction lies in its ability for long term continuous operation with continuous organic feeding and oxidant regeneration with feed water removal. In this report we present the results of fully integrated MEO system. The task of operating the continuous feed MEO system for a long time was made possible by continuously removing the feed water using an evaporator set up. The rate of Ce(IV) regeneration in the electrochemical cell and the consumption for the pesticide destruction was matched based on carbon content of the pesticides. It was found that under the optimized experimental conditions for Ce(III) oxidation, organic addition and water removal destruction efficiency of ca. 99% was obtained for all pesticides studied. It was observed that the Ce(IV) concentration was maintained nearly the same throughout the experiment. The stable operation for 6h proved that the process can be used for real applications and for possible scale up for the destruction of larger volumes of toxic organic wastes.

  13. Measurement of the electric conductivity of tungsten in a continuous liquid-to-gas transition

    NASA Astrophysics Data System (ADS)

    Korobenko, V. N.; Rakhel, A. D.; Savvatimskiy, A. I.; Fortov, V. E.

    2002-12-01

    A method is developed that makes it possible to investigate the transition of a metal from a condensed to a gaseous phase while maintaining almost uniform temperature and pressure distributions in the sample. The method consists in the pulsed Joule heating of a sample in the form of a thin foil strip placed between two relatively thick glass plates. This method is used to measure the conductivity of tungsten in a process during which the pressure in the sample is maintained at a level of 40-60 kbar and the density of the sample decreases from the normal solid density to a density 20 to 30 times lower. It is found that, along the 40-kbar isobar, the density dependence of the conductivity of tungsten changes radically at a certain density value, at which it has a pronounced kink. At the kink, the density of tungsten is approximately ten times lower than its characteristic solid density, and the internal energy is about two times the sublimation energy. The method makes it possible to carry out experiments with the almost isobaric heating of tungsten in the parameter range in which the effect in question takes place. No such effect is detected in nonisobaric processes.

  14. Analytical model and new structure of the enhancement-mode polarization-junction HEMT with vertical conduction channel

    NASA Astrophysics Data System (ADS)

    Yang, Chao; Xiong, Jiayun; Wei, Jie; Wu, Junfeng; Peng, Fu; Deng, Siyu; Zhang, Bo; Luo, Xiaorong

    2016-04-01

    A novel enhancement-mode (E-mode) polarization-junction HEMT with vertical conduction channel (PVC-HEMT) is proposed, and its analytical model for threshold voltage (Vth) is presented. It has two features: one is GaN/AlGaN/GaN double hetero-structure, the other is that source and drain locate at the same side of trench-type MOS gate (T-gate), and the source contacts with the T-gate, which forms vertical conduction channel (VC). The 2-D hole gas (2-DHG) and 2-D electron gas (2-DEG) are formed at the GaN-top/AlGaN and AlGaN/GaN-buffer interface, respectively, forming the polarization-junction. First, the E-mode operation is realized because 2-DHG under the source prevents the electrons injecting from source to 2-DEG, breaking through the conventional E-mode method by depleting 2-DEG under the gate. Second, a uniform electric field (E-field) distribution is achieved due to the assisted depletion effect by polarization-junction. Third, the source reduces the E-field peak at the T-gate side and modulates the E-field distribution. The breakdown voltage (BV) of PVC-HEMT is 705 V and specific ON-resistance (RON,sp) is 1.18 mΩ cm2. Compared with conventional HEMT (C-HEMT), PVC-HEMT has a smaller size due to the special location of the source and T-gate. An analytic threshold voltage model is presented and the analytical results agree well with the simulated results.

  15. Dual-mode ion switching conducting polymer films as high energy supercapacitor materials

    SciTech Connect

    Naoi, Katsuhiko; Oura, Yasushi

    1995-12-31

    The electropolymerized polypyrrole films formed from micellar solution of anionic surfactants, viz., Dodecylbenzene sulfonate (DBS), showed potential-dependent anion and cation ion switching behavior and the peculiar columnar structure. The formation process and the redox of the polypyrrole was studied with the in situ atomic force microscopy (AFM) and electrochemical quartz crystal microbalance (EQCM) methods. In-situ AFM observation clearly indicated that such a columnar structure started to form around critical charge densities of 60--100 mC cm{sup {minus}2}. The cyclic voltammogram for the PPy doped with DBS{sup {minus}} film showed two redox couples, each of which corresponds to a cation and an anion exchange process. Thus, the film behaves as a dual-mode ion doping/undoping exchanger. As the PPy film was prepared in higher concentration of the surfactant dopant, where the micelles are formed in solution, the resulting film showed a considerably higher (ca. three orders of magnitude) diffusion coefficient compared to ordinary PPy films so far reported. Such an enhanced diffusivity of ions could be attributed to a peculiar structure of the polymer formed. The feasibility of such polypyrrole in use of supercapacitor material was discussed.

  16. Thermal conductivity measurements of high and low thermal conductivity films using a scanning hot probe method in the 3ω mode and novel calibration strategies

    NASA Astrophysics Data System (ADS)

    Wilson, Adam A.; Muñoz Rojo, Miguel; Abad, Begoña; Perez, Jaime Andrés; Maiz, Jon; Schomacker, Jason; Martín-Gonzalez, Marisol; Borca-Tasciuc, Diana-Andra; Borca-Tasciuc, Theodorian

    2015-09-01

    This work discusses measurement of thermal conductivity (k) of films using a scanning hot probe method in the 3ω mode and investigates the calibration of thermal contact parameters, specifically the thermal contact resistance (RthC) and thermal exchange radius (b) using reference samples with different thermal conductivities. RthC and b were found to have constant values (with b = 2.8 +/- 0.3 μm and Rthc = 44 927 +/- 7820 K W-1) for samples with thermal conductivity values ranging from 0.36 W K-1 m-1 to 1.1 W K-1 m-1. An independent strategy for the calibration of contact parameters was developed and validated for samples in this range of thermal conductivity, using a reference sample with a previously measured Seebeck coefficient and thermal conductivity. The results were found to agree with the calibration performed using multiple samples of known thermal conductivity between 0.36 and 1.1 W K-1 m-1. However, for samples in the range between 16.2 W K-1 m-1 and 53.7 W K-1 m-1, calibration experiments showed the contact parameters to have considerably different values: Rthc = 40 191 +/- 1532 K W-1 and b = 428 +/- 24 nm. Finally, this work demonstrates that using these calibration procedures, measurements of both highly conductive and thermally insulating films on substrates can be performed, as the measured values obtained were within 1-20% (for low k) and 5-31% (for high k) of independent measurements and/or literature reports. Thermal conductivity results are presented for a SiGe film on a glass substrate, Te film on a glass substrate, polymer films (doped with Fe nano-particles and undoped) on a glass substrate, and Au film on a Si substrate.This work discusses measurement of thermal conductivity (k) of films using a scanning hot probe method in the 3ω mode and investigates the calibration of thermal contact parameters, specifically the thermal contact resistance (RthC) and thermal exchange radius (b) using reference samples with different thermal

  17. Insight into the collective vibrational modes driving ultralow thermal conductivity of perovskite solar cells

    NASA Astrophysics Data System (ADS)

    Yue, Sheng-Ying; Zhang, Xiaoliang; Qin, Guangzhao; Yang, Jiayue; Hu, Ming

    2016-09-01

    The past few years have witnessed a rapid evolution of hybrid organic-inorganic perovskite solar cells as an unprecedented photovoltaic technology with both relatively low cost and high-power conversion. The fascinating physical and chemical properties of perovskites are benefited from their unique crystal structures represented by the general chemical formula A M X3 , where the A cations occupy the hollows formed by the M X3 octahedra and thus balance the charge of the entire network. Despite a vast amount of theoretical and experimental investigations have been dedicated to the structural stability, electrical, and optical properties of hybrid halide perovskite materials in relation to their applications in solar cells, the thermal transport property, another critical parameter to the design and optimization of relevant solar cell modules, receives less attention. In this paper, we evaluate the lattice thermal conductivity of a representative methylammonium lead triiodide perovskite (CH3NH3PbI3 ) with direct nonequilibrium ab initio molecular dynamics simulation. Resorting to full first-principles calculations, we illustrate the details of the mysterious vibration of the methylammonium cluster (CH3NH3+ ) and present an unambiguous picture of how the organic cluster interacting with the inorganic cage and how the collective motions of the organic cluster drags the thermal transport, which provide fundamental understanding of the ultralow thermal conductivity of CH3NH3PbI3 . We also reveal the strongly localized phonons associated with the internal motions of the CH3NH3+ cluster, which contribute little to the total thermal conductivity. The importance of the CH3NH3+ cluster to the structural instability is also discussed in terms of the unconventional dispersion curves by freezing the partial freedoms of the organic cluster. These results provide more quantitative description of organic-inorganic interaction and coupling dynamics from accurate first

  18. FDNS CFD Code Benchmark for RBCC Ejector Mode Operation: Continuing Toward Dual Rocket Effects

    NASA Technical Reports Server (NTRS)

    West, Jeff; Ruf, Joseph H.; Turner, James E. (Technical Monitor)

    2000-01-01

    Computational Fluid Dynamics (CFD) analysis results are compared with benchmark quality test data from the Propulsion Engineering Research Center's (PERC) Rocket Based Combined Cycle (RBCC) experiments to verify fluid dynamic code and application procedures. RBCC engine flowpath development will rely on CFD applications to capture the multi -dimensional fluid dynamic interactions and to quantify their effect on the RBCC system performance. Therefore, the accuracy of these CFD codes must be determined through detailed comparisons with test data. The PERC experiments build upon the well-known 1968 rocket-ejector experiments of Odegaard and Stroup by employing advanced optical and laser based diagnostics to evaluate mixing and secondary combustion. The Finite Difference Navier Stokes (FDNS) code [2] was used to model the fluid dynamics of the PERC RBCC ejector mode configuration. Analyses were performed for the Diffusion and Afterburning (DAB) test conditions at the 200-psia thruster operation point, Results with and without downstream fuel injection are presented.

  19. Quasi-continuous burst-mode laser for high-speed planar imaging.

    PubMed

    Slipchenko, Mikhail N; Miller, Joseph D; Roy, Sukesh; Gord, James R; Danczyk, Stephen A; Meyer, Terrence R

    2012-04-15

    The pulse-burst duration of a compact burst-mode Nd:YAG laser is extended by one order of magnitude compared to previous flashlamp-pumped designs by incorporating a fiber oscillator and diode-pumped solid-state amplifiers. The laser has a linewidth of <2 GHz at 1064.3 nm with 150 mJ per individual pulse at 10 kHz. The performance of the system is evaluated by using the third-harmonic output at 354.8 nm for high-speed planar laser-induced fluorescence of formaldehyde in a lifted methane-air diffusion flame. A total of 100 and 200 sequential images of unsteady fluid-flame interactions are acquired at repetition rates of 10 kHz and 20 kHz, respectively.

  20. Optical and ionospheric phenomena at EISCAT under continuous X-mode HF pumping

    NASA Astrophysics Data System (ADS)

    Blagoveshchenskaya, N. F.; Borisova, T. D.; Kosch, M.; Sergienko, T.; Brändström, U.; Yeoman, T. K.; Häggström, I.

    2014-12-01

    We present experimental results from multiinstrument observations in the high-latitude ionospheric F2 layer at the EISCAT (European Incoherent Scatter Scientific Association) heating facility. The results come from a set of experiments, when an X-polarized HF pump wave at high heater frequencies (fH > 6.0 MHz) was injected into the F region of the ionosphere toward the magnetic zenith. Experiments were carried out under quiet magnetic conditions with an effective radiated power of 458-548 MW. HF pumping was produced at different heater frequencies, away from electron gyroharmonic frequencies, and different durations of heater pulses. We show the first experimental evidence of the excitation of artificial optical emissions at red (630 nm) and green (557.7 nm) lines in the high-latitude ionospheric F2 layer induced by an X-polarized HF pump wave. Intensities at red and green lines varied in the range 110-950 R and 50-350 R, respectively, with a ratio of green to red line of 0.35-0.5. The results of optical observations are compared with behaviors of the HF-enhanced ion and plasma lines from EISCAT UHF incoherent scatter radar data and small-scale field-aligned artificial irregularities from Cooperative UK Twin Located Auroral Sounding System observations. It was found that the X-mode radio-induced optical emissions coexisted with HF-enhanced ion and plasma lines and strong artificial field-aligned irregularities throughout the whole heater pulse. It is indicative that parametric decay or oscillating two-stream instabilities were not quenched by fully established small-scale field-aligned artificial irregularities excited by an X-mode HF pump wave.

  1. Computation of the eddy-current modes of three-dimensional conducting bodies

    NASA Astrophysics Data System (ADS)

    Gabbay, Jonathan E.; Scott, Waymond R.

    2016-05-01

    Low-frequency electromagnetic induction (EMI) sensors are commonly used in subsurface detection applications because of their efficacy at detecting even small fragments of metal when they are buried near the surface. This efficacy can become a shortcoming when the detector is expected to locate specific classes of targets that are buried among metallic clutter. For these applications, broadband EMI sensors have shown considerable promise at being able to detect, classify and locate targets such as land mines, and discriminate between them and the clutter with low false-alarm rates. In such cases, where differentiating targets from clutter is a significant obstacle, detection strategies based on the discrete spectrum of relaxation frequencies (DSRF) have been shown to be highly effective. For such purposes, a dictionary of DSRF of targets of interest must be computed a priori. Several classes of targets such as sphere and rings have DSRF that can be derived analytically, however, in general, the DSRF must be computed numerically. Previously, numerical strategies have been presented for thin conducting shells and rotationaly symmetric targets. In this paper, we will present a strategy to compute the DSRF of arbitrary conducting targets using a null space free Jacobi Davidson iteration (NFJD).

  2. Disorder Effect on Chiral Edge Modes and Anomalous Hall Conductance in Weyl Semimetals

    NASA Astrophysics Data System (ADS)

    Takane, Yositake

    2016-12-01

    Typical Weyl semimetals host chiral surface states and hence show an anomalous Hall response. Although a Weyl semimetal phase is known to be robust against weak disorder, the effect of disorder on chiral states has not been fully clarified so far. We study the behavior of such chiral states in the presence of disorder and its consequences on an anomalous Hall response, focusing on a thin slab of Weyl semimetal with chiral surface states along its edge. It is shown that weak disorder does not disrupt chiral edge states but crucially affects them owing to the renormalization of a mass parameter: the number of chiral edge states changes depending on the strength of disorder. It is also shown that the Hall conductance is quantized when the Fermi level is located near Weyl nodes within a finite-size gap. This quantization of the Hall conductance collapses once the strength of disorder exceeds a critical value, suggesting that it serves as a probe to distinguish a Weyl semimetal phase from a diffusive anomalous Hall metal phase.

  3. Single-mode electrically pumped GaSb-based VCSELs emitting continuous-wave at 2.4 and 2.6 μm

    NASA Astrophysics Data System (ADS)

    Bachmann, Alexander; Arafin, Shamsul; Kashani-Shirazi, Kaveh

    2009-12-01

    Vertical-cavity surface-emitting lasers (VCSELs) are perfect light sources for spectroscopic applications, where properties such as continuous-wave (cw) operation, single-mode emission, high lifetime and often low power consumption are crucial. For applications such as tunable diode laser absorption spectroscopy (TDLAS), there is a growing interest in laser devices emitting in the near- to mid-infrared wavelength range, where many environmentally and technologically important gases show strong absorption lines. The (AlGaIn)(AsSb) material system based on GaSb is the material of choice for covering the 2.0-3.3 μm range. In this paper, we report on electrically pumped single-mode VCSELs with emission wavelengths of 2.4 and 2.6 μm, operating cw at room temperature and beyond. By (electro-) thermal tuning, the emission wavelength can be tuned mode-hop free over a range of several nanometers. In addition, low threshold currents of several milliamperes promise mobile application. In the devices, a structured buried tunnel junction with subsequent overgrowth has been used in order to achieve efficient current confinement, reduced optical losses and increased electrical conductivity. Furthermore, strong optical confinement is introduced in the lasers due to laterally differing cavity lengths.

  4. Strength and conductivity of unidirectional copper composites reinforced by continuous SiC fibers

    NASA Astrophysics Data System (ADS)

    Kimmig, S.; Allen, I.; You, J. H.

    2013-09-01

    A SiC long fiber-reinforced copper composite offers a beneficial combination of high strength and high thermal conductivity at elevated temperatures. Both properties make the composite a promising material for the heat sink of high-heat-flux components. In this work, we developed a novel Cu/SiCf composite using the Sigma fiber. Based on HIP technique, a metallurgical process was established for fabricating high quality specimens using a TiC interface coating. Extensive tensile tests were conducted on the unidirectionally reinforced composite at 20 °C and 300 °C for a wide range of fiber volume fraction (Vf). In this paper, a large amount of test data is presented. The transversal thermal conductivity varies from 260 to 130 W/mK at 500 °C as Vf is increased from 13% to 37%. The tensile strength reached up to 1246 MPa at 20 °C for Vf = 37.6%, where the fracture strain was limited to 0.8%. The data of both elastic modulus and ultimate strength exhibited a good agreement with the rule-of-mixture predictions indicating a high quality of the materials. The strength of the composite with the Sigma fibers turned out to be superior to those of the SCS6 fibers at 300 °C, although the SCS6 fiber actually has a higher strength than the Sigma fiber. The fractographic pictures of tension test and fiber push-out test manifested a sufficient interfacial bonding. Unidirectional copper composite reinforced by long SiC fibers was fabricated using the Sigma SM1140+ fiber for a wide range of fiber volume fraction from 14% to 40%. Extensive tensile tests were carried out at RT and 300 °C. The data of ultimate strength as well as elastic modulus exhibited a good agreement with the rule-of-mixture predictions indicating a high quality of the materials. In terms of the tensile strength, the Cu/Sigma composite turned out to be superior to the previous Cu/SCS6 composite at 300 °C, while comparable at RT, although the SCS6 fiber has a higher strength than the Sigma fiber. Such a

  5. A patch-array antenna single-mode low electrical dissipation continuous wave terahertz quantum cascade laser

    NASA Astrophysics Data System (ADS)

    Bosco, L.; Bonzon, C.; Ohtani, K.; Justen, M.; Beck, M.; Faist, J.

    2016-11-01

    We introduce a double metal terahertz quantum cascade laser meant for astrophysical heterodyne measurements. The laser ridge is embedded in benzocyclobutene, and the device exhibits single mode, continuous wave operation around 4.745 THz with a peak power of almost 1.8 mW at 10 K and a power consumption of ≈1.6 W. Moreover, thanks to the integration of a top metal contact with a patch array antenna for light out-coupling the beam of the emitted light has a low-divergence single-lobe profile and an FWHM of ≈30°.

  6. Tube-in-tube reactor as a useful tool for homo- and heterogeneous olefin metathesis under continuous flow mode.

    PubMed

    Skowerski, Krzysztof; Czarnocki, Stefan J; Knapkiewicz, Paweł

    2014-02-01

    A tube-in-tube reactor was successfully applied in homo- and heterogeneous olefin metathesis reactions under continuous flow mode. It was shown that the efficient removal of ethylene facilitated by connection of the reactor with a vacuum pump significantly improves the outcome of metathesis reactions. The beneficial aspects of this approach are most apparent in reactions performed at low concentration, such as macrocyclization reactions. The established system allows achievement of both improved yield and selectivity, and is ideal for industrial applications. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Closed-loop ARS mode for scanning ion conductance microscopy with improved speed and stability for live cell imaging applications

    NASA Astrophysics Data System (ADS)

    Jung, Goo-Eun; Noh, Hanaul; Shin, Yong Kyun; Kahng, Se-Jong; Baik, Ku Youn; Kim, Hong-Bae; Cho, Nam-Joon; Cho, Sang-Joon

    2015-06-01

    Scanning ion conductance microscopy (SICM) is an increasingly useful nanotechnology tool for non-contact, high resolution imaging of live biological specimens such as cellular membranes. In particular, approach-retract-scanning (ARS) mode enables fast probing of delicate biological structures by rapid and repeated approach/retraction of a nano-pipette tip. For optimal performance, accurate control of the tip position is a critical issue. Herein, we present a novel closed-loop control strategy for the ARS mode that achieves higher operating speeds with increased stability. The algorithm differs from that of most conventional (i.e., constant velocity) approach schemes as it includes a deceleration phase near the sample surface, which is intended to minimize the possibility of contact with the surface. Analysis of the ion current and tip position demonstrates that the new mode is able to operate at approach speeds of up to 250 μm s-1. As a result of the improved stability, SICM imaging with the new approach scheme enables significantly improved, high resolution imaging of subtle features of fixed and live cells (e.g., filamentous structures & membrane edges). Taken together, the results suggest that optimization of the tip approach speed can substantially improve SICM imaging performance, further enabling SICM to become widely adopted as a general and versatile research tool for biological studies at the nanoscale level.

  8. Investigation of single-mode fiber degradation by 405-nm continuous-wave laser light

    NASA Astrophysics Data System (ADS)

    Gonschior, Cornell P.; Klein, Karl-Friedrich; Menzel, Matthias; Sun, Tong; Grattan, Kenneth T. V.

    2014-12-01

    The degradation of 405-nm fiber-coupled diode laser systems with more than 50 mW power was investigated in detail with focus on the effects occurring at the input end. The coupling and transmission loss of the laser light were associated with the growth of a projection and a periodic structure on the input surface. To avoid this degradation, a short launch fiber with a good surface quality was used at the input end. In this way, the power transmission was stabilized for at least one month. However, structural degradation was noticed on the output surface of the single-mode fiber. To investigate this effect, the damaged samples were measured after different periods of time and examined with a scanning electron microscope and with an atomic force microscope. Reproducible spherical projections with a submicron periodic structure were found in the core region. Additionally, the spectral loss of the fiber was measured, showing the formation of color centers in the deep ultraviolet along the length of the fiber. These investigations were accompanied by simulations of the growth of the structure on the output surface. The influence of the structure was mainly on the divergence angle of the emitted laser beam, reducing the beam quality for applications.

  9. Ice Formation via Deposition Mode Nucleation Onto Dust Particulates: The University of Toronto Continuous Flow Diffusion Chamber

    NASA Astrophysics Data System (ADS)

    Kanji, Z. A.; Abbatt, J. P.; Cotton, R.; Demott, P.; Jones, H.; Möhler, O.; Stetzer, O.

    2008-12-01

    Laboratory studies are described whereby the heterogeneous ice nucleating ability of various dust samples were studied, for particles suspended in a newly built thermal gradient continuous flow diffusion chamber (TG-CFDC). Ice formation is observed using an optical particle counter (OPC) and the relative humidity (RH) and temperature conditions of the flow system are validated by observing homogenous freezing of H2SO4 aerosols. At the Fourth International Ice Nucleation Workshop (ICIS 07) in Karslruhe, Germany this system was used to investigate ice nucleation primarily in the vapor deposition mode, for Arizona Test Dust (ATD), Israeli Desert Dust (ID), Canary Island Dust (CID), Saharan Dust (SD), Graphite Spark Soot, Snomax® (dead bacteria) and live bacteria. The aerosol size was in the submicron range with an approximate cut off of 700 nm and a mode of 350 nm. Temperatures for nucleation were varied from 265 - 230 K. The dust aerosols were generally found to be more efficient than soot. At warmer temperatures (263 K) the bacteria were found to be active in the deposition mode which was not the case for dusts. Among the various dust types at 248 K, the CID was more efficient than ATD at nucleating ice when efficiency is based on lowest onset RH conditions for ice formation in our chamber. We also present preliminary results for the effect of total surface area versus size of aerosols on ice nucleation using ATD as a surrogate for naturally occurring mineral dust.

  10. Continuous Carbon Nanotube-Ultrathin Graphite Hybrid Foams for Increased Thermal Conductivity and Suppressed Subcooling in Composite Phase Change Materials.

    PubMed

    Kholmanov, Iskandar; Kim, Jaehyun; Ou, Eric; Ruoff, Rodney S; Shi, Li

    2015-12-22

    Continuous ultrathin graphite foams (UGFs) have been actively researched recently to obtain composite materials with increased thermal conductivities. However, the large pore size of these graphitic foams has resulted in large thermal resistance values for heat conduction from inside the pore to the high thermal conductivity graphitic struts. Here, we demonstrate that the effective thermal conductivity of these UGF composites can be increased further by growing long CNT networks directly from the graphite struts of UGFs into the pore space. When erythritol, a phase change material for thermal energy storage, is used to fill the pores of UGF-CNT hybrids, the thermal conductivity of the UGF-CNT/erythritol composite was found to increase by as much as a factor of 1.8 compared to that of a UGF/erythritol composite, whereas breaking the UGF-CNT bonding in the hybrid composite resulted in a drop in the effective room-temperature thermal conductivity from about 4.1 ± 0.3 W m(-1) K(-1) to about 2.9 ± 0.2 W m(-1) K(-1) for the same UGF and CNT loadings of about 1.8 and 0.8 wt %, respectively. Moreover, we discovered that the hybrid structure strongly suppresses subcooling of erythritol due to the heterogeneous nucleation of erythritol at interfaces with the graphitic structures.

  11. Continuous-wave to pulse regimes for a family of passively mode-locked lasers with saturable nonlinearity

    NASA Astrophysics Data System (ADS)

    Dikandé, Alain M.; Voma Titafan, J.; Essimbi, B. Z.

    2017-10-01

    The transition dynamics from continuous-wave to pulse regimes of operation for a generic model of passively mode-locked lasers with saturable absorbers, characterized by an active medium with non-Kerr nonlinearity, are investigated analytically and numerically. The system is described by a complex Ginzburg–Landau equation with a general m:n saturable nonlinearity (i.e {I}m/{(1+{{Γ }}I)}n, where I is the field intensity and m and n are two positive numbers), coupled to a two-level gain equation. An analysis of stability of continuous waves, following the modulational instability approach, provides a global picture of the self-starting dynamics in the system. The analysis reveals two distinct routes depending on values of the couple (m, n), and on the dispersion regime: in the normal dispersion regime, when m = 2 and n is arbitrary, the self-starting requires positive values of the fast saturable absorber and nonlinearity coefficients, but negative values of these two parameters for the family with m = 0. However, when the spectral filter is negative, the laser can self-start for certain values of the input field and the nonlinearity saturation coefficient Γ. The present work provides a general map for the self-starting mechanisms of rare-earth doped figure-eight fiber lasers, as well as Kerr-lens mode-locked solid-state lasers.

  12. Butanol production by immobilised Clostridium acetobutylicum in repeated batch, fed-batch, and continuous modes of fermentation.

    PubMed

    Dolejš, Igor; Krasňan, Vladimír; Stloukal, Radek; Rosenberg, Michal; Rebroš, Martin

    2014-10-01

    Clostridium acetobutylicum immobilised in polyvinylalcohol, lens-shaped hydrogel capsules (LentiKats(®)) was studied for production of butanol and other products of acetone-butanol-ethanol fermentation. After optimising the immobilisation protocol for anaerobic bacteria, continuous, repeated batch, and fed-batch fermentations in repeated batch mode were performed. Using glucose as a substrate, butanol productivity of 0.41 g/L/h and solvent productivity of 0.63 g/L/h were observed at a dilution rate of 0.05 h(-1) during continuous fermentation with a concentrated substrate (60 g/L). Through the process of repeated batch fermentation, the duration of fermentation was reduced from 27.8h (free-cell fermentation) to 3.3h (immobilised cells) with a solvent productivity of 0.77 g/L/h (butanol 0.57 g/L/h). The highest butanol and solvent productivities of 1.21 and 1.91 g/L/h were observed during fed-batch fermentation operated in repeated batch mode with yields of butanol (0.15 g/g) and solvents (0.24 g/g), respectively, produced per gram of glucose. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Distributed computing strategies for processing of FT-ICR MS imaging datasets for continuous mode data visualization

    SciTech Connect

    Smith, Donald F.; Schulz, Carl; Konijnenburg, Marco; Kilic, Mehmet; Heeren, Ronald M.

    2015-03-01

    High-resolution Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry imaging enables the spatial mapping and identification of biomolecules from complex surfaces. The need for long time-domain transients, and thus large raw file sizes, results in a large amount of raw data (“big data”) that must be processed efficiently and rapidly. This can be compounded by largearea imaging and/or high spatial resolution imaging. For FT-ICR, data processing and data reduction must not compromise the high mass resolution afforded by the mass spectrometer. The continuous mode “Mosaic Datacube” approach allows high mass resolution visualization (0.001 Da) of mass spectrometry imaging data, but requires additional processing as compared to featurebased processing. We describe the use of distributed computing for processing of FT-ICR MS imaging datasets with generation of continuous mode Mosaic Datacubes for high mass resolution visualization. An eight-fold improvement in processing time is demonstrated using a Dutch nationally available cloud service.

  14. Distributed computing strategies for processing of FT-ICR MS imaging datasets for continuous mode data visualization.

    PubMed

    Smith, Donald F; Schulz, Carl; Konijnenburg, Marco; Kilic, Mehmet; Heeren, Ron M A

    2015-03-01

    High-resolution Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry imaging enables the spatial mapping and identification of biomolecules from complex surfaces. The need for long time-domain transients, and thus large raw file sizes, results in a large amount of raw data ("big data") that must be processed efficiently and rapidly. This can be compounded by large-area imaging and/or high spatial resolution imaging. For FT-ICR, data processing and data reduction must not compromise the high mass resolution afforded by the mass spectrometer. The continuous mode "Mosaic Datacube" approach allows high mass resolution visualization (0.001 Da) of mass spectrometry imaging data, but requires additional processing as compared to feature-based processing. We describe the use of distributed computing for processing of FT-ICR MS imaging datasets with generation of continuous mode Mosaic Datacubes for high mass resolution visualization. An eight-fold improvement in processing time is demonstrated using a Dutch nationally available cloud service.

  15. Electrically continuous graphene from single crystal copper verified by terahertz conductance spectroscopy and micro four-point probe.

    PubMed

    Buron, Jonas D; Pizzocchero, Filippo; Jessen, Bjarke S; Booth, Timothy J; Nielsen, Peter F; Hansen, Ole; Hilke, Michael; Whiteway, Eric; Jepsen, Peter U; Bøggild, Peter; Petersen, Dirch H

    2014-11-12

    The electrical performance of graphene synthesized by chemical vapor deposition and transferred to insulating surfaces may be compromised by extended defects, including for instance grain boundaries, cracks, wrinkles, and tears. In this study, we experimentally investigate and compare the nano- and microscale electrical continuity of single layer graphene grown on centimeter-sized single crystal copper with that of previously studied graphene films, grown on commercially available copper foil, after transfer to SiO2 surfaces. The electrical continuity of the graphene films is analyzed using two noninvasive conductance characterization methods: ultrabroadband terahertz time-domain spectroscopy and micro four-point probe, which probe the electrical properties of the graphene film on different length scales, 100 nm and 10 μm, respectively. Ultrabroadband terahertz time-domain spectroscopy allows for measurement of the complex conductance response in the frequency range 1-15 terahertz, covering the entire intraband conductance spectrum, and reveals that the conductance response for the graphene grown on single crystalline copper intimately follows the Drude model for a barrier-free conductor. In contrast, the graphene grown on commercial copper foil shows a distinctly non-Drude conductance spectrum that is better described by the Drude-Smith model, which incorporates the effect of preferential carrier backscattering associated with extended, electronic barriers with a typical separation on the order of 100 nm. Micro four-point probe resistance values measured on graphene grown on single crystalline copper in two different voltage-current configurations show close agreement with the expected distributions for a continuous 2D conductor, in contrast with previous observations on graphene grown on commercial copper foil. The terahertz and micro four-point probe conductance values of the graphene grown on single crystalline copper shows a close to unity correlation, in

  16. A continuous mode data acquisition technique for proton recoil proportional counter neutron spectrometers

    SciTech Connect

    Bennett, E.F.

    1989-03-01

    The existing proton recoil proportional counter measurement technique used at FNS for joint FNS-ANL fusion blanket neutron spectroscopy requires that numerous piece-wise (but overlapping) measurements be carried out at a sequence of fixed counter voltages. The composite results of all of these independent measurements are required to construct a single neutron spectrum. This approach has been found to be both inefficient and subject to systematic errors. An alternative approach, in which data is acquired continuously using a slow time modulation of the high voltage bias supply, is here described. The electronics requirements are consistent with the basic detector/amplifier systems now operable at FNS. Some additional hardware including a programmable high voltage bias supply and a random amplitude test pulse generator are necessary. A description of the electronics and data acquisition hardware for these measurements will be provided at a later date. In this report we emphasize the numerical procedures involved to acquire and reduce data, and provide an illustrative example using one of the hardest neutron spectra readily available for this work at ANL. 6 refs., 26 figs.

  17. Density-gradient-assisted centrifugal microfluidics: an approach to continuous-mode particle separation.

    PubMed

    Ukita, Yoshiaki; Oguro, Takayuki; Takamura, Yuzuru

    2017-06-01

    Centrifugal microfluidics has been recognized as a promising pumping method in microfluidics because of its simplicity, easiness of automation, and parallel processing. However, the patterning of stripe flow in centrifugal microfluidics is challenging because a fluid is significantly affected by the Coriolis force, which produces an intrinsic secondary flow. This paper reports a technical and design strategy for centrifugal microfluidics called "density-gradient-assisted centrifugal microfluidics." The flow behavior is observed with the presence of a density gradient and without a density gradient in two concentrically traveling phase flows. As a result, clear stripe flow pattern is observed with a density difference of 0.05 g/cm(3) between water and a percoll solution at a flow rate of 11.8 μl/s (7 ml/10 min) and spinning speed of 3000 rpm. In contrast, without a density gradient, it is necessary to reduce the flow rate and spinning speed to 0.1 μl/s and 1000 rpm, respectively. This paper also presents the use of a density gradient to assist in focusing resin (polystyrene) particles on the boundary of a stripe flow pattern that consists of water and percoll with different densities. Moreover, the density-based separation and sorting of particles in a mixed particle suspension is demonstrated. Polystyrene is selectively focused on the boundary, but silica particles are separated from the focused trajectory due to a difference in density. The separated particles are continuously sorted into different reservoirs with polystyrene and silica separation efficiencies of 96.5% and 98.5%, respectively. The pumping, stripe flow pattern formation, particle concentration, and sorting are simultaneously realized by applying a density gradient and centrifugal force. Therefore, this principle can realize a very simple technique for label-free particle separation by just spinning a disk device and can be applied in other applications by the use of the density

  18. The Influences of Presentation Modes and Conducting Gestures on the Perceptions of Expressive Choral Performance of High School Musicians Attending a Summer Choral Camp

    ERIC Educational Resources Information Center

    Napoles, Jessica

    2013-01-01

    The purpose of this study was to examine the influences of presentation modes (audio and visual) on perceptions of expressive choral performance. The stimulus recording included four choral selections, each conducted by a different conductor in two ways: using expressive conducting gestures and using strict conducting gestures. Three groups of…

  19. High-Throughput Continuous Hydrothermal Synthesis of Transparent Conducting Aluminum and Gallium Co-doped Zinc Oxides.

    PubMed

    Howard, Dougal P; Marchand, Peter; McCafferty, Liam; Carmalt, Claire J; Parkin, Ivan P; Darr, Jawwad A

    2017-04-10

    High-throughput continuous hydrothermal flow synthesis was used to generate a library of aluminum and gallium-codoped zinc oxide nanoparticles of specific atomic ratios. Resistivities of the materials were determined by Hall Effect measurements on heat-treated pressed discs and the results collated into a conductivity-composition map. Optimal resistivities of ∼9 × 10(-3) Ω cm were reproducibly achieved for several samples, for example, codoped ZnO with 2 at% Ga and 1 at% Al. The optimum sample on balance of performance and cost was deemed to be ZnO codoped with 3 at% Al and 1 at% Ga.

  20. Continuous higher-order sliding mode control with time-varying gain for a class of uncertain nonlinear systems.

    PubMed

    Han, Yaozhen; Liu, Xiangjie

    2016-05-01

    This paper presents a continuous higher-order sliding mode (HOSM) control scheme with time-varying gain for a class of uncertain nonlinear systems. The proposed controller is derived from the concept of geometric homogeneity and super-twisting algorithm, and includes two parts, the first part of which achieves smooth finite time stabilization of pure integrator chains. The second part conquers the twice differentiable uncertainty and realizes system robustness by employing super-twisting algorithm. Particularly, time-varying switching control gain is constructed to reduce the switching control action magnitude to the minimum possible value while keeping the property of finite time convergence. Examples concerning the perturbed triple integrator chains and excitation control for single-machine infinite bus power system are simulated respectively to demonstrate the effectiveness and applicability of the proposed approach. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  1. Design of an ultra low power third order continuous time current mode ΣΔ modulator for WLAN applications

    PubMed Central

    Behzadi, Kobra; Baghelani, Masoud

    2013-01-01

    This paper presents a third order continuous time current mode ΣΔ modulator for WLAN 802.11b standard applications. The proposed circuit utilized feedback architecture with scaled and optimized DAC coefficients. At circuit level, we propose a modified cascade current mirror integrator with reduced input impedance which results in more bandwidth and linearity and hence improves the dynamic range. Also, a very fast and precise novel dynamic latch based current comparator is introduced with low power consumption. This ultra fast comparator facilitates increasing the sampling rate toward GHz frequencies. The modulator exhibits dynamic range of more than 60 dB for 20 MHz signal bandwidth and OSR of 10 while consuming only 914 μW from 1.8 V power supply. The FoM of the modulator is calculated from two different methods, and excellent performance is achieved for proposed modulator. PMID:25685504

  2. Continuous scanning of a time-reversed ultrasonically encoded optical focus by reflection-mode digital phase conjugation

    PubMed Central

    Suzuki, Yuta; Tay, Jian Wei; Yang, Qiang; Wang, Lihong V.

    2014-01-01

    Time-reversed ultrasonically encoded (TRUE) optical focusing in turbid media was previously implemented using both analog and digital phase conjugation. The digital approach, in addition to its large energy gain, can improve the focal intensity and resolution by iterative focusing. However, performing iterative focusing at each focal position can be time-consuming. Here, we show that by gradually moving the focal position, the TRUE focal intensity is improved, as in iterative focusing at a fixed position, and can be continuously scanned to image fluorescent targets in a shorter time. Also, our setup is the first demonstration of TRUE focusing using a digital phase conjugate mirror in reflection mode, which is more suitable for practical applications. PMID:24978506

  3. Ubiquitination switches EphA2 vesicular traffic from a continuous safeguard to a finite signalling mode

    PubMed Central

    Sabet, Ola; Stockert, Rabea; Xouri, Georgia; Brüggemann, Yannick; Stanoev, Angel; Bastiaens, Philippe I. H.

    2015-01-01

    Autocatalytic phosphorylation of receptor tyrosine kinases (RTKs) enables diverse, context-dependent responses to extracellular signals but comes at the price of autonomous, ligand-independent activation. Using a conformational biosensor that reports on the kinase activity of the cell guidance ephrin receptor type-A (EphA2) in living cells, we observe that autonomous EphA2 activation is suppressed by vesicular recycling and dephosphorylation by protein tyrosine phosphatases 1B (PTP1B) near the pericentriolar recycling endosome. This spatial segregation of catalytically superior PTPs from RTKs at the plasma membrane is essential to preserve ligand responsiveness. Ligand-induced clustering, on the other hand, promotes phosphorylation of a c-Cbl docking site and ubiquitination of the receptor, thereby redirecting it to the late endosome/lysosome. We show that this switch from cyclic to unidirectional receptor trafficking converts a continuous suppressive safeguard mechanism into a transient ligand-responsive signalling mode. PMID:26292967

  4. Fiber powered sensing system for a long reach single mode fiber link and non-continuous applications

    NASA Astrophysics Data System (ADS)

    Rosolem, J. B.; Bassan, F. R.; Pereira, F. R.; Penze, R. S.; Leonardi, A. A.; Nascimento, C. A. M.

    2014-05-01

    This work describes a non-continuous sensor operating technique in order to achieve a long reach sensing system, using power over fiber (PoF) in single mode fiber (SMF). Due to the use of super-capacitors and logical circuits in the sensor unit, the energy provided by PoF can be stored and used in an appropriated time. We demonstrated this approach with a micro video camera sensor powered by a 4.4-km SMF link in laboratory and by a 1.6-km link using optical ground wire cable (OPWG), installed between an electrical power substation and a tower of 138-kV overhead transmission line (OTL).

  5. A novel alternate feeding mode for semi-continuous anaerobic co-digestion of food waste with chicken manure.

    PubMed

    Wang, Ming; Sun, Xianli; Li, Pengfei; Yin, Lili; Liu, Dan; Zhang, Yingwei; Li, Wenzhe; Zheng, Guoxiang

    2014-07-01

    A novel alternate feeding mode was introduced to study the possibilities of improving methane yield from anaerobic co-digestion of food waste (FW) with chicken manure (CM). Two kinds of feeding sequence (a day FW and next day CM (FM/CM), two days FM and the third day CM (FW/FM/CM)) were investigated in semi-continuous anaerobic digestion and lasted 225 days, and the mono-digestions of FW and CM were used as control group, respectively. The feeding sequence of FW/CM and mono-digestion of CM were observed to fail to produce gas at hydraulic retention time (HRT) of 70 days due to the ammonia inhibition, however, the mode of FW/FM/CM was proved to successfully run at HRT of 35 days with a higher OLR of 2.50 kg L(-1)d(-1) and obtain a higher methane production rate of 507.58 ml g(-1) VS and volumetric biogas production rate of 2.1 L L(-1)d(-1).

  6. High-power LED light sources for optical measurement systems operated in continuous and overdriven pulsed modes

    NASA Astrophysics Data System (ADS)

    Stasicki, Bolesław; Schröder, Andreas; Boden, Fritz; Ludwikowski, Krzysztof

    2017-06-01

    The rapid progress of light emitting diode (LED) technology has recently resulted in the availability of high power devices with unprecedented light emission intensities comparable to those of visible laser light sources. On this basis two versatile devices have been developed, constructed and tested. The first one is a high-power, single-LED illuminator equipped with exchangeable projection lenses providing a homogenous light spot of defined diameter. The second device is a multi-LED illuminator array consisting of a number of high-power LEDs, each integrated with a separate collimating lens. These devices can emit R, G, CG, B, UV or white light and can be operated in pulsed or continuous wave (CW) mode. Using an external trigger signal they can be easily synchronized with cameras or other devices. The mode of operation and all parameters can be controlled by software. Various experiments have shown that these devices have become a versatile and competitive alternative to laser and xenon lamp based light sources. The principle, design, achieved performances and application examples are given in this paper.

  7. Negative ion rich plasmas in continuous and pulsed wave modes in a minimum-B magnetic field

    SciTech Connect

    Sahu, Debaprasad; Pandey, Shail; Aneja, Jyoti; Bhattacharjee, Sudeep

    2012-12-15

    Generation of hydrogen negative ion rich plasmas is investigated in continuous wave (CW) and pulse modulated (PM) wave modes of 2.45 GHz in a minimum-B magnetic field. The waves are launched directly into the plasma device and utilize wave particle resonances for high density plasma generation. In CW operation, the chamber is divided into two sections, namely, the source and downstream region, separated by a transverse magnetic field that allows only cold electrons ({approx}1 eV) into the downstream region helpful for the generation of negative ions. The H{sup -} density is measured by the second derivative beat method and is compared with the values obtained from a steady state model and the extracted current density. In the pulsed mode, temporal filtering generates negative ion rich plasmas in the afterglow phase. The H{sup -} density in the afterglow is estimated using saturation current ratio method and the results are compared with a time dependent model using particle balance equations. The essential idea in both the filtering techniques is to assist generation of negative ions and prevent its destruction by hot electrons.

  8. Atomistic simulations of ammonium-based protic ionic liquids: steric effects on structure, low frequency vibrational modes and electrical conductivity.

    PubMed

    Sunda, Anurag Prakash; Mondal, Anirban; Balasubramanian, Sundaram

    2015-02-14

    Protic ionic liquids (PILs) are of great interest as electrolytes in various energy applications. Molecular dynamics simulations of trialkylammonium (with varying alkyl group such as methyl, ethyl, and n-propyl) triflate PILs are performed to characterize the influence of the alkyl group on the acidic site (N-H) of the ammonium cation. Spatial distribution function of anions over this site on the cation reveals significant influence of the length of alkyl tail on intermolecular structure. Vibrational density of states and normal modes are calculated for bulk liquids to probe atomic displacements in the far infrared region. The observed N-H···O hydrogen bond stretching vibration in 155-165 cm(-1) frequency region agrees well with experiments. Trends in electrical conductivity calculated using Nernst-Einstein and Green-Kubo relation are in qualitative agreement with experiments. The self-diffusion coefficient and the electrical conductivity is highest for N,N-dimethyl-N-ethylammonium triflate ([N112][TfO]) and is lowest for N,N-di-n-propyl-N-methylammonium triflate ([N133][TfO]) IL.

  9. Proposal on How To Conduct a Biopharmaceutical Process Failure Mode and Effect Analysis (FMEA) as a Risk Assessment Tool.

    PubMed

    Zimmermann, Hartmut F; Hentschel, Norbert

    2011-01-01

    With the publication of the quality guideline ICH Q9 "Quality Risk Management" by the International Conference on Harmonization, risk management has already become a standard requirement during the life cycle of a pharmaceutical product. Failure mode and effect analysis (FMEA) is a powerful risk analysis tool that has been used for decades in mechanical and electrical industries. However, the adaptation of the FMEA methodology to biopharmaceutical processes brings about some difficulties. The proposal presented here is intended to serve as a brief but nevertheless comprehensive and detailed guideline on how to conduct a biopharmaceutical process FMEA. It includes a detailed 1-to-10-scale FMEA rating table for occurrence, severity, and detectability of failures that has been especially designed for typical biopharmaceutical processes. The application for such a biopharmaceutical process FMEA is widespread. It can be useful whenever a biopharmaceutical manufacturing process is developed or scaled-up, or when it is transferred to a different manufacturing site. It may also be conducted during substantial optimization of an existing process or the development of a second-generation process. According to their resulting risk ratings, process parameters can be ranked for importance and important variables for process development, characterization, or validation can be identified. Health authorities around the world ask pharmaceutical companies to manage risk during development and manufacturing of pharmaceuticals. The so-called failure mode and effect analysis (FMEA) is an established risk analysis tool that has been used for decades in mechanical and electrical industries. However, the adaptation of the FMEA methodology to pharmaceutical processes that use modern biotechnology (biopharmaceutical processes) brings about some difficulties, because those biopharmaceutical processes differ from processes in mechanical and electrical industries. The proposal presented here

  10. Synchronized growth and neutral lipid accumulation in Chlorella sorokiniana FC6 IITG under continuous mode of operation.

    PubMed

    Kumar, Vikram; Muthuraj, Muthusivaramapandian; Palabhanvi, Basavaraj; Das, Debasish

    2016-01-01

    Synchronized growth and neutral lipid accumulation with high lipid productivity under mixotrophic growth of the strain Chlorella sorokiniana FC6 IITG was achieved via manipulation of substrates feeding mode and supplementation of lipid elicitors in the growth medium. Screening and optimization of lipid elicitors resulted in lipid productivity of 110.59mgL(-1)day(-1) under the combined effect of lipid inducers sodium acetate and sodium chloride. Fed-batch cultivation of the strain in bioreactor with intermittent feeding of limiting nutrients and lipid inducer resulted in maximum biomass and lipid productivity of 2.08 and 0.97gL(-1)day(-1) respectively. Further, continuous production of biomass with concomitant lipid accumulation was demonstrated via continuous feeding of BG11 media supplemented with lipid inducers sodium acetate and sodium chloride. The improved biomass and lipid productivity in chemostat was found to be 2.81 and 1.27gL(-1)day(-1) respectively operated at a dilution rate of 0.54day(-1).

  11. Pressurised hot water extraction in continuous flow mode for thermolabile compounds: extraction of polyphenols in red onions.

    PubMed

    Liu, Jiayin; Sandahl, Margareta; Sjöberg, Per J R; Turner, Charlotta

    2014-01-01

    Extraction and analysis of labile compounds in complex sample matrices, such as plants, is often a big analytical challenge. In this work, the use of a "green and clean" pressurised hot water extraction (PHWE) approach performed in continuous flow mode is explored. Experimental data for extraction and degradation kinetics of selected compounds were utilised to develop a continuous flow extraction (CFE) method targeting thermolabile polyphenols in red onions, with detection by high-performance liquid chromatography (HPLC)-diode array detection (DAD)-mass spectrometry (MS). Water containing ethanol and formic acid was used as extraction solvent. Method performance was focused on extraction yield with minimal analyte degradation. By adjusting the flow rate of the extraction solvent, degradation effects were minimised, and complete extraction could be achieved within 60 min. The CFE extraction yields of the polyphenols investigated were 80-90 % of the theoretically calculated quantitative yields and were significantly higher than the yields obtained by conventional methanol extraction and static batch extraction (70-79 and 58-67 % of the theoretical yields, respectively). The precision of the developed method was lower than 8 % expressed as relative standard deviation.

  12. EVIDENCE OF THERMAL CONDUCTION SUPPRESSION IN A SOLAR FLARING LOOP BY CORONAL SEISMOLOGY OF SLOW-MODE WAVES

    SciTech Connect

    Wang, Tongjiang; Ofman, Leon; Provornikova, Elena; Sun, Xudong; Davila, Joseph M.

    2015-09-20

    Analysis of a longitudinal wave event observed by the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory is presented. A time sequence of 131 Å images reveals that a C-class flare occurred at one footpoint of a large loop and triggered an intensity disturbance (enhancement) propagating along it. The spatial features and temporal evolution suggest that a fundamental standing slow-mode wave could be set up quickly after meeting of two initial disturbances from the opposite footpoints. The oscillations have a period of ∼12 minutes and a decay time of ∼9 minutes. The measured phase speed of 500 ± 50 km s{sup −1} matches the sound speed in the heated loop of ∼10 MK, confirming that the observed waves are of slow mode. We derive the time-dependent temperature and electron density wave signals from six AIA extreme-ultraviolet channels, and find that they are nearly in phase. The measured polytropic index from the temperature and density perturbations is 1.64 ± 0.08 close to the adiabatic index of 5/3 for an ideal monatomic gas. The interpretation based on a 1D linear MHD model suggests that the thermal conductivity is suppressed by at least a factor of 3 in the hot flare loop at 9 MK and above. The viscosity coefficient is determined by coronal seismology from the observed wave when only considering the compressive viscosity dissipation. We find that to interpret the rapid wave damping, the classical compressive viscosity coefficient needs to be enhanced by a factor of 15 as the upper limit.

  13. Effect of conductivity and concentration on the sample stream in the transverse axis of a continuous flow electrophoresis chamber

    NASA Technical Reports Server (NTRS)

    Miller, Teresa Y.; Williams, George O.; Snyder, Robert S.

    1985-01-01

    The resolution of continuous flow electrophoresis systems is generally measured by the spread of the sample bands in the direction of the electrophoretic migration. This paper evaluates the cross section of the sample bands in the plane perpendicular to the flow and shows that the spread in the direction perpendicular to the migration increased significantly with the applied electric field. Concentrated samples of monodisperse latex particles and vinyltoluene T-butylstyrene particles in sample buffers of different electrical conductivities were used to map the shape of the sample bands relative to the zero electric field case. As the electric field was applied, the sample band spread from an initial diameter of only one-third the chamber thickness until it approached the chamber walls where electroosmosis significantly reduced the resolution of separation. It can be shown, however, that it is possible to minimize these distortions by careful sample preparation and experiment design.

  14. Effect of conductivity and concentration on the sample stream in the transverse axis of a continuous flow electrophoresis chamber

    NASA Technical Reports Server (NTRS)

    Miller, Teresa Y.; Williams, George O.; Snyder, Robert S.

    1985-01-01

    The resolution of continuous flow electrophoresis systems is generally measured by the spread of the sample bands in the direction of the electrophoretic migration. This paper evaluates the cross section of the sample bands in the plane perpendicular to the flow and shows that the spread in the direction perpendicular to the migration increased significantly with the applied electric field. Concentrated samples of monodisperse latex particles and vinyltoluene T-butylstyrene particles in sample buffers of different electrical conductivities were used to map the shape of the sample bands relative to the zero electric field case. As the electric field was applied, the sample band spread from an initial diameter of only one-third the chamber thickness until it approached the chamber walls where electroosmosis significantly reduced the resolution of separation. It can be shown, however, that it is possible to minimize these distortions by careful sample preparation and experiment design.

  15. Characterization of continuous and pulsed emission modes of a hybrid micro focus x-ray source for medical imaging applications

    NASA Astrophysics Data System (ADS)

    Ghani, Muhammad U.; Wong, Molly D.; Ren, Liqiang; Wu, Di; Zheng, Bin; Rong, John. X.; Wu, Xizeng; Liu, Hong

    2017-05-01

    The aim of this study was to quantitatively characterize a micro focus x-ray tube that can operate in both continuous and pulsed emission modes. The micro focus x-ray source (Model L9181-06, Hamamatsu Photonics, Japan) has a varying focal spot size ranging from 16 μm to 50 μm as the source output power changes from 10 to 39 W. We measured the source output, beam quality, focal spot sizes, kV accuracy, spectra shapes and spatial resolution. Source output was measured using an ionization chamber for various tube voltages (kVs) with varying current (μA) and distances. The beam quality was measured in terms of half value layer (HVL), kV accuracy was measured with a non-invasive kV meter, and the spectra was measured using a compact integrated spectrometer system. The focal spot sizes were measured using a slit method with a CCD detector with a pixel pitch of 22 μm. The spatial resolution was quantitatively measured using the slit method with a CMOS flat panel detector with a 50 μm pixel pitch, and compared to the qualitative results obtained by imaging a contrast bar pattern. The focal spot sizes in the vertical direction were smaller than that of the horizontal direction, the impact of which was visible when comparing the spatial resolution values. Our analyses revealed that both emission modes yield comparable imaging performances in terms of beam quality, spectra shape and spatial resolution effects. There were no significantly large differences, thus providing the motivation for future studies to design and develop stable and robust cone beam imaging systems for various diagnostic applications.

  16. Lower Energy Endovenous Laser Ablation of the Great Saphenous Vein with 980 nm Diode Laser in Continuous Mode

    SciTech Connect

    Kim, Hyun S. Nwankwo, Ikechi J.; Hong, Kelvin; McElgunn, Patrick S.J.

    2006-02-15

    Purpose. To assess clinical outcomes, complication rates, and unit energy applied using 980 nm diode endovenous laser treatment at 11 watts for symptomatic great saphenous vein (GSV) incompetence and reflux disease. Methods. Thirty-four consecutive ablation therapies with a 980 nm diode endovenous laser at 11 watts were studied. The diagnosis of GSV incompetence with reflux was made by clinical evaluation and duplex Doppler examinations. The treated GSVs had a mean diameter of 1.19 cm (range 0.5-2.2 cm). The patients were followed with clinical evaluation and color flow duplex studies up to 18.5 months (mean 12.19 months {+-} 4.18). Results. Using 980 nm diode endovenous laser ablation in continuous mode, 100% technical success was noted. The mean length of GSVs treated was 33.82 cm (range 15-45 cm). The mean energy applied during the treatment was 1,155.81 joules (J) {+-} 239.50 (range 545.40-1620 J) for a mean treatment duration of 90.77 sec {+-} 21.77. The average laser fiber withdrawal speed was 0.35 cm/sec {+-} 0.054. The mean energy applied per length of GSV was 35.16 J/cm {+-} 8.43. Energy fluence, calculated separately for each patient, averaged 9.82 J/cm{sup 2} {+-} 4.97. At up to 18.5 months follow-up (mean 12.19 months), 0% recanalization was noted; 92% clinical improvement was achieved. There was no major complication. Minor complications included 1 patient with hematoma at the percutaneous venotomy site, 1 patient with thrombophlebitis on superficial tributary varices of the treated GSV, 24% ecchymoses, and 32% self-limiting hypersensitivity/tenderness/'pulling' sensation along the treatment area. One patient developed temporary paresthesia. Four endovenous laser ablation treatments (12%) were followed by adjunctive sclerotherapies for improved cosmetic results. Conclusion. Endovenous laser ablation treatment of GSV using a 980 nm diode laser at 11 watts in continuous mode appears safe and effective. Mean energy applied per treated GSV length of 35

  17. Lower energy endovenous laser ablation of the great saphenous vein with 980 nm diode laser in continuous mode.

    PubMed

    Kim, Hyun S; Nwankwo, Ikechi J; Hong, Kelvin; McElgunn, Patrick S J

    2006-01-01

    To assess clinical outcomes, complication rates, and unit energy applied using 980 nm diode endovenous laser treatment at 11 watts for symptomatic great saphenous vein (GSV) incompetence and reflux disease. Thirty-four consecutive ablation therapies with a 980 nm diode endovenous laser at 11 watts were studied. The diagnosis of GSV incompetence with reflux was made by clinical evaluation and duplex Doppler examinations. The treated GSVs had a mean diameter of 1.19 cm (range 0.5-2.2 cm). The patients were followed with clinical evaluation and color flow duplex studies up to 18.5 months (mean 12.19 months +/- 4.18). Using 980 nm diode endovenous laser ablation in continuous mode, 100% technical success was noted. The mean length of GSVs treated was 33.82 cm (range 15-45 cm). The mean energy applied during the treatment was 1,155.81 joules (J) +/- 239.50 (range 545.40-1620 J) for a mean treatment duration of 90.77 sec +/- 21.77. The average laser fiber withdrawal speed was 0.35 cm/sec +/- 0.054. The mean energy applied per length of GSV was 35.16 J/cm +/- 8.43. Energy fluence, calculated separately for each patient, averaged 9.82 J/cm(2) +/- 4.97. At up to 18.5 months follow-up (mean 12.19 months), 0% recanalization was noted; 92% clinical improvement was achieved. There was no major complication. Minor complications included 1 patient with hematoma at the percutaneous venotomy site, 1 patient with thrombophlebitis on superficial tributary varices of the treated GSV, 24% ecchymoses, and 32% self-limiting hypersensitivity/tenderness/"pulling" sensation along the treatment area. One patient developed temporary paresthesia. Four endovenous laser ablation treatments (12%) were followed by adjunctive sclerotherapies for improved cosmetic results. Endovenous laser ablation treatment of GSV using a 980 nm diode laser at 11 watts in continuous mode appears safe and effective. Mean energy applied per treated GSV length of 35.16 J/cm or mean laser fluence of 9.82 J/cm(2

  18. Towards cooperative guidance and control of highly automated vehicles: H-Mode and Conduct-by-Wire.

    PubMed

    Flemisch, Frank Ole; Bengler, Klaus; Bubb, Heiner; Winner, Hermann; Bruder, Ralph

    2014-01-01

    This article provides a general ergonomic framework of cooperative guidance and control for vehicles with an emphasis on the cooperation between a human and a highly automated vehicle. In the twenty-first century, mobility and automation technologies are increasingly fused. In the sky, highly automated aircraft are flying with a high safety record. On the ground, a variety of driver assistance systems are being developed, and highly automated vehicles with increasingly autonomous capabilities are becoming possible. Human-centred automation has paved the way for a better cooperation between automation and humans. How can these highly automated systems be structured so that they can be easily understood, how will they cooperate with the human? The presented research was conducted using the methods of iterative build-up and refinement of framework by triangulation, i.e. by instantiating and testing the framework with at least two derived concepts and prototypes. This article sketches a general, conceptual ergonomic framework of cooperative guidance and control of highly automated vehicles, two concepts derived from the framework, prototypes and pilot data. Cooperation is exemplified in a list of aspects and related to levels of the driving task. With the concept 'Conduct-by-Wire', cooperation happens mainly on the guidance level, where the driver can delegate manoeuvres to the automation with a specialised manoeuvre interface. With H-Mode, a haptic-multimodal interaction with highly automated vehicles based on the H(orse)-Metaphor, cooperation is mainly done on guidance and control with a haptically active interface. Cooperativeness should be a key aspect for future human-automation systems. Especially for highly automated vehicles, cooperative guidance and control is a research direction with already promising concepts and prototypes that should be further explored. The application of the presented approach is every human-machine system that moves and includes high

  19. Novel structure design of composite proton exchange membranes with continuous and through-membrane proton-conducting channels

    NASA Astrophysics Data System (ADS)

    Wang, Hang; Tang, Chenxiao; Zhuang, Xupin; Cheng, Bowen; Wang, Wei; Kang, Weimin; Li, Hongjun

    2017-10-01

    The primary goal of this study is to develop a high-performanced proton exchange membrane with the characteristics of through-membrane and continuous solution blown nanofibers as proton-conducting channels. The curled sulfonated phenolphthalein poly (ether sulfone) and poly (vinylidene fluoride) nanofibers were separately fabricated through the solution blowing process which is a new nanofiber fabricating method with high productivity, then they were fabricated into a sandwich-structured mat. Then this sandwich-structured mat was hot-pressed to form the designed structure using different melting temperatures of the two polymers by melting and making poly (vinylidene fluoride) flow into the phenolphthalein poly (ether sulfone) nanofiber mat. The characteristics of the composite membrane, such as morphology and performance of the membrane, were investigated. The characterization results proved the successful preparation of the membrane structure. Performance results showed that the novel structured membrane with through-membrane nanofibers significantly improved water swelling and methanol permeability, though its conductivity is lower than that of Nafion, the cell performance showed comparable results. Therefore, the novel structure design can be considered as a promising method for preparing of proton exchange membranes.

  20. A novel counterpulse drive mode of continuous-flow left ventricular assist devices can minimize intracircuit backward flow during pump weaning.

    PubMed

    Ando, Masahiko; Nishimura, Takashi; Takewa, Yoshiaki; Ogawa, Daisuke; Yamazaki, Kenji; Kashiwa, Koichi; Kyo, Shunei; Ono, Minoru; Taenaka, Yoshiyuki; Tatsumi, Eisuke

    2011-03-01

    Recent developments in adjunct therapeutic options for end-stage heart failure have enabled us to remove implanted left ventricular assist devices (LVADs) from more patients than before. However, a safe and proper protocol for pump-off trials is yet to be established, because diastolic backward flow in a pump circuit turns up when it is driven at low-flow conditions. We have developed a novel drive mode of centrifugal pumps that can change its rotational speed in synchronization with the cardiac cycle of the native heart. The purpose of this study was to test-drive this novel system of a centrifugal pump in a mock circulation and to evaluate the effect of the counterpulse mode, which increases pump speed just in diastole, on the amount of this nonphysiological intracircuit retrograde flow. A rotary pump (EVAHEART, Sun Medical Technology Research Corporation) was connected to the mock circulation by left ventricular uptake and ascending aortic return. We drove it in the following four conditions: (A) continuous mode at 1500 rpm, (B) counterpulse mode (systolic 1500 rpm, diastolic 2500 rpm), (C) continuous mode at 2000 rpm, and (D) counterpulse mode (systolic 2000 rpm, diastolic 2500 rpm). Data concerning the rotation speed, pump flow, left ventricular pressure, aortic pressure, and pressure head (i.e., aortic pressure-left ventricular pressure) in each condition were collected. After data collection, we analyzed pump flow, and calculated its forward and backward flow. Counterpulse mode decreased the amounts of pump backward flow compared with the continuous mode [mean backward flow, -4, -1, -0.5, 0 l/min, in (A), (B), (C), and (D) conditions, respectively]. The actual amounts of mean backward flow can be different from those in clinical situations; however, this novel drive mode for rotary pumps can relatively decrease pump backward flow during pump weaning and can be beneficial for safe and proper pump-off trials. Further investigations in in vivo settings are

  1. From Research Question to Conducting a Randomized Controlled Trial on Continuous Antibiotic Prophylaxis in Prenatal Hydronephrosis: A Rational Stepwise Process.

    PubMed

    Braga, Luis H; Easterbrook, Bethany; Jegatheeswaran, Kizanee; Lorenzo, Armando J

    2016-01-01

    Continuous antibiotic prophylaxis (CAP) use to prevent urinary tract infections (UTI) in infants with prenatal hydronephrosis (HN) remains controversial. Lack of consensus guidelines and diverse practice patterns for postnatal management of HN highlight the dire need for higher level of evidence studies. Herein, we aim to describe the steps from developing a well-defined research question to execute a multicentered randomized controlled trial (RCT) to address the issue of CAP use in patients with prenatal HN. The steps involved were (1) choosing the proper research question, (2) survey of practice patterns and establishing clinical equipoise, (3) systematic review of the literature, (4) reviewing own practice, (5) longitudinal prospective study, (6) pilot study, (7) cost-utility analysis, and (8) definitive RCT (clinical trials registry number: NCT01140516). An update of our previous systematic review was conducted using two electronic databases and gray literature from 2010 to 2015. Eligibility criteria included studies of children <2 years old with postnatally confirmed prenatal HN, receiving CAP or not, and reporting on development of UTIs, capturing information on voiding cystourethrogram result and HN grade. Full-text screening was conducted by two independent reviewers. UTI rates in patients with high-grade HN were compared across different study designs. Finally, blinded comparative analysis of UTI rates between placebo and treatment groups was carried out using chi-square test. UTI rates in patients with high-grade HN by their respective study design were: 25% for systematic review, 20% for retrospective study, 21% for prospective and pilot studies, and 13% for the definitive RCT thus far. Regardless of the type of study design, patients with hydroureteronephrosis had significantly higher (threefold to sixfold) UTI rates than those with isolated HN. Our updated systematic review yielded 486 citations, of which 9 (n = 1987 infants) observational

  2. Automatic Differentiation of Normal and Continuous Adventitious Respiratory Sounds Using Ensemble Empirical Mode Decomposition and Instantaneous Frequency.

    PubMed

    Lozano, Manuel; Fiz, José Antonio; Jané, Raimon

    2016-03-01

    Differentiating normal from adventitious respiratory sounds (RS) is a major challenge in the diagnosis of pulmonary diseases. Particularly, continuous adventitious sounds (CAS) are of clinical interest because they reflect the severity of certain diseases. This study presents a new classifier that automatically distinguishes normal sounds from CAS. It is based on the multiscale analysis of instantaneous frequency (IF) and envelope (IE) calculated after ensemble empirical mode decomposition (EEMD). These techniques have two major advantages over previous techniques: high temporal resolution is achieved by calculating IF-IE and a priori knowledge of signal characteristics is not required for EEMD. The classifier is based on the fact that the IF dispersion of RS signals markedly decreases when CAS appear in respiratory cycles. Therefore, CAS were detected by using a moving window to calculate the dispersion of IF sequences. The study dataset contained 1494 RS segments extracted from 870 inspiratory cycles recorded from 30 patients with asthma. All cycles and their RS segments were previously classified as containing normal sounds or CAS by a highly experienced physician to obtain a gold standard classification. A support vector machine classifier was trained and tested using an iterative procedure in which the dataset was randomly divided into training (65%) and testing (35%) sets inside a loop. The SVM classifier was also tested on 4592 simulated CAS cycles. High total accuracy was obtained with both recorded (94.6% ± 0.3%) and simulated (92.8% ± 3.6%) signals. We conclude that the proposed method is promising for RS analysis and classification.

  3. Reconstruction of the in-plane mode shape of a rotating tire with a continuous scanning measurement using the Hilbert-Huang transform.

    PubMed

    Lee, Jongsuh; Wang, Semyung; Pluymers, Bert; Desmet, Wim; Kindt, Peter

    2015-02-01

    Generally, the dynamic characteristics (natural frequency, damping, and mode shape) of a structure can be estimated by experimental modal analysis. Among these dynamic characteristics, mode shape requires multiple measurements of the structure at different positions, which increases the experimental cost and time. Recently, the Hilbert-Huang transform (HHT) method has been introduced to extract mode-shape information from a continuous measurement, which requires vibration measurements from one position to another position continuously with a non-contact sensor. In this research study, an effort has been made to estimate the mode shapes of a rolling tire with a single measurement instead of using the conventional experimental setup (i.e., measurement of the vibration of a rolling tire at multiple positions similar to the case of a non-rotating structure), which is used to estimate the dynamic behavior of a rolling tire. For this purpose, HHT, which was used in the continuous measurement of a non-rotating structure in previous research studies, has been used for the case of a rotating system in this study. Ambiguous mode combinations can occur in this rotating system, and therefore, a method to overcome this ambiguity is proposed in this study. In addition, the specific phenomenon for a rotating system is introduced, and the effect of this phenomenon with regard to the obtained results through HHT is investigated.

  4. Use of Continuous Specific Conductance to Differentiate the Sources of Water to an Agricultural Stream With Subsurface Drainage Networks

    NASA Astrophysics Data System (ADS)

    Smith, E. A.; Thornburg, J.; Capel, P. D.

    2008-12-01

    The sources of water to natural streams include direct precipitation, overland flow, and ground-water inflow. In glaciated areas, the presence of artificial surface and subsurface drainage networks, a common practice for removing excess water from agricultural fields, provides additional pathways of water movement to the stream. The artificial drainage of agricultural fields allows rainfall to move quickly through the catchment to the stream transporting nutrients, pesticides and other agricultural-related constituents. A largely agricultural (about 90%), 31 km2 subcatchment of the South Fork of the Iowa River in north-central Iowa was studied for two years. Discharge and specific conductance (SC) were measured continuously and discreet water samples were obtained for analyses of nutrients and other constituents. SC is an electrical measurement of the total ion content in the water. The SC of the rain and ground-water is about 10 microS/cm and 800-1,200 microS/cm, respectively. The typical, base-flow SC of the stream is 700-800 microS/cm. Within minutes after a substantial rain event, the stream discharge increases and the SC decreases (often times below 200"nmicroS/cm). The rain water is processed through the catchment before it reaches the stream via direct overland flow, preferential flow to subsurface drains, vertical drains attached to subsurface drains in ponded areas, and/or soil infiltration to ground-water. Water moving through each of these pathways has different characteristic time scales and different degrees of interactions with the soil yielding different ionic content, thus different SC. Both the discharge and SC concurrently return to the typical base-flow values over the following days and weeks. This strong relation between rainfall, discharge and SC is used to calculate the relative importance and time scale of the various hydrologic pathways. In addition to the two-year stream record, complementary discharge and SC data were collected in two

  5. 20 CFR 220.185 - The Board may conduct a review to find out whether the annuitant continues to be disabled.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false The Board may conduct a review to find out whether the annuitant continues to be disabled. 220.185 Section 220.185 Employees' Benefits RAILROAD... review to find out whether the annuitant continues to be disabled. After the Board finds that...

  6. Continuous tuning of two-section, single-mode terahertz quantum-cascade lasers by fiber-coupled, near-infrared illumination

    NASA Astrophysics Data System (ADS)

    Hempel, Martin; Röben, Benjamin; Niehle, Michael; Schrottke, Lutz; Trampert, Achim; Grahn, Holger T.

    2017-05-01

    The dynamical tuning due to rear facet illumination of single-mode, terahertz (THz) quantum-cascade lasers (QCLs) which employ distributed feedback gratings are compared to the tuning of single-mode QCLs based on two-section cavities. The THz QCLs under investigation emit in the range of 3 to 4.7 THz. The tuning is achieved by illuminating the rear facet of the QCL with a fiber-coupled light source emitting at 777 nm. Tuning ranges of 5.0 and 11.9 GHz under continuous-wave and pulsed operation, respectively, are demonstrated for a single-mode, two-section cavity QCL emitting at about 3.1 THz, which exhibits a side-mode suppression ratio better than -25 dB.

  7. Entanglement transfer from two-mode continuous variable SU(2) cat states to discrete qubits systems in Jaynes-Cummings Dimers

    PubMed Central

    Ran, Du; Hu, Chang-Sheng; Yang, Zhen-Biao

    2016-01-01

    We study the entanglement transfer from a two-mode continuous variable system (initially in the two-mode SU(2) cat states) to a couple of discrete two-state systems (initially in an arbitrary mixed state), by use of the resonant Jaynes-Cummings (JC) interaction. We first quantitatively connect the entanglement transfer to non-Gaussianity of the two-mode SU(2) cat states and find a positive correlation between them. We then investigate the behaviors of the entanglement transfer and find that it is dependent on the initial state of the discrete systems. We also find that the largest possible value of the transferred entanglement exhibits a variety of behaviors for different photon number as well as for the phase angle of the two-mode SU(2) cat states. We finally consider the influences of the noise on the transferred entanglement. PMID:27553881

  8. A Review and Empirical Comparison of Three Treatments for Adolescent Males with Conduct and Personality Disorder: Mode Deactivation Therapy, Cognitive Behavior Therapy and Social Skills Training

    ERIC Educational Resources Information Center

    Apsche, Jack A.; Bass, Christopher K.

    2006-01-01

    This research study compared the efficacy of three treatment methodologies for adolescent males in residential treatment with conduct disorders and/or personality dysfunctions and documented problems with physical and sexual aggression. The results showed that Mode Deactivation Therapy, an advanced form of cognitive behavioral therapy based on…

  9. Numerical simulation of the optimal two-mode attacks for two-way continuous-variable quantum cryptography in reverse reconciliation

    NASA Astrophysics Data System (ADS)

    Zhang, Yichen; Li, Zhengyu; Zhao, Yijia; Yu, Song; Guo, Hong

    2017-02-01

    We analyze the security of the two-way continuous-variable quantum key distribution protocol in reverse reconciliation against general two-mode attacks, which represent all accessible attacks at fixed channel parameters. Rather than against one specific attack model, the expression of secret key rates of the two-way protocol are derived against all accessible attack models. It is found that there is an optimal two-mode attack to minimize the performance of the protocol in terms of both secret key rates and maximal transmission distances. We identify the optimal two-mode attack, give the specific attack model of the optimal two-mode attack and show the performance of the two-way protocol against the optimal two-mode attack. Even under the optimal two-mode attack, the performances of two-way protocol are still better than the corresponding one-way protocol, which shows the advantage of making double use of the quantum channel and the potential of long-distance secure communication using a two-way protocol.

  10. Family Mode Deactivation Therapy in a Residential Setting: Treating Adolescents with Conduct Disorder and Multi-Axial Diagnosis

    ERIC Educational Resources Information Center

    Apsche, Jack A.; Bass, Christopher K.; Zeiter, J. Scott; Houston, Marsha Ann

    2008-01-01

    Mode Deactivation Therapy (MDT) has been shown to be an effective treatment for a variety of adolescent disorders including emotional dysregulation, behavioral dysregulation, physical aggression, sexual aggression, and many harmful symptoms of anxiety and traumatic stress. MDT Family Therapy has been effective in reducing family disharmony in case…

  11. Acoustic mode measurements in the inlet of a model turbofan using a continuously rotating rake - Data collection/analysis techniques

    NASA Technical Reports Server (NTRS)

    Hall, David G.; Heidelberg, Laurence; Konno, Kevin

    1993-01-01

    The rotating microphone measurement technique and data analysis procedures are documented which are used to determine circumferential and radial acoustic mode content in the inlet of the Advanced Ducted Propeller (ADP) model. Circumferential acoustic mode levels were measured at a series of radial locations using the Doppler frequency shift produced by a rotating inlet microphone probe. Radial mode content was then computed using a least squares curve fit with the measured radial distribution for each circumferential mode. The rotating microphone technique is superior to fixed-probe techniques because it results in minimal interference with the acoustic modes generated by rotor-stator interaction. This effort represents the first experimental implementation of a measuring technique developed by T. G. Sofrin. Testing was performed in the NASA Lewis Low Speed Anechoic Wind Tunnel at a simulated takeoff condition of Mach 0.2. The design is included of the data analysis software and the performance of the rotating rake apparatus. The effect of experiment errors is also discussed.

  12. Acoustic mode measurements in the inlet of a model turbofan using a continuously rotating rake: Data collection/analysis techniques

    NASA Technical Reports Server (NTRS)

    Hall, David G.; Heidelberg, Laurence; Konno, Kevin

    1993-01-01

    The rotating microphone measurement technique and data analysis procedures are documented which are used to determine circumferential and radial acoustic mode content in the inlet of the Advanced Ducted Propeller (ADP) model. Circumferential acoustic mode levels were measured at a series of radial locations using the Doppler frequency shift produced by a rotating inlet microphone probe. Radial mode content was then computed using a least squares curve fit with the measured radial distribution for each circumferential mode. The rotating microphone technique is superior to fixed-probe techniques because it results in minimal interference with the acoustic modes generated by rotor-stator interaction. This effort represents the first experimental implementation of a measuring technique developed by T. G. Sofrin. Testing was performed in the NASA Lewis Low Speed Anechoic Wind Tunnel at a simulated takeoff condition of Mach 0.2. The design is included of the data analysis software and the performance of the rotating rake apparatus. The effect of experiment errors is also discussed.

  13. Acoustic mode measurements in the inlet of a model turbofan using a continuously rotating rake - Data collection/analysis techniques

    NASA Technical Reports Server (NTRS)

    Hall, David G.; Heidelberg, Laurence; Konno, Kevin

    1993-01-01

    The rotating microphone measurement technique and data analysis procedures are documented which are used to determine circumferential and radial acoustic mode content in the inlet of the Advanced Ducted Propeller (ADP) model. Circumferential acoustic mode levels were measured at a series of radial locations using the Doppler frequency shift produced by a rotating inlet microphone probe. Radial mode content was then computed using a least squares curve fit with the measured radial distribution for each circumferential mode. The rotating microphone technique is superior to fixed-probe techniques because it results in minimal interference with the acoustic modes generated by rotor-stator interaction. This effort represents the first experimental implementation of a measuring technique developed by T. G. Sofrin. Testing was performed in the NASA Lewis Low Speed Anechoic Wind Tunnel at a simulated takeoff condition of Mach 0.2. The design is included of the data analysis software and the performance of the rotating rake apparatus. The effect of experiment errors is also discussed.

  14. High precision and continuous measurements of mesophyll and stomatal conductance to CO2 diffusion during photosynthesis using QCL

    NASA Astrophysics Data System (ADS)

    Kodama, N.; Wada, R.; Nakayama, T.; Takemura, K.; Takahashi, K.; Hanba, Y. T.; Matsumi, Y.

    2011-12-01

    The diffusion of CO2 within leaves during photosynthesis can be an important limiting factor for productivity. Mesophyll conductance had been thought to be infinite or constant over the time. Recent studies, however, have revealed that mesophyll conductance is altered by growth environment,and may respond rapidly to some environmental variables such as light and CO2 concentration. Mesophyll conductance has been suggested to be dependent on leaf anatomical and morphological structures, and aquaporin have been proven to play an important role in CO2 transport across cell membranes. In this study we used transgenic Eucalyptus overexpressing radish aquaporin PIP2 to investigate the effect of aquaporin on mesophyll conductance. We hypothesized that stomatal and mesophyll conductance may respond differently to environmental alterations. A mid-infrared laser absorption spectrometer (QCL; Aerodyne research Inc.) was coupled to a photosynthesis system to allow simultaneous measurement of exchange of CO2 and its isotopologues.We found that mesophyll conductance responded more rapidly to alteration of the light intensity compared to stomatal conductance, regardless of aquaporin expression. However, mesophyll conductance was higher in the leaves with higher aquaporin content. The mesophyll response was completed within 5 minutes, considerably faster than the stomatal response to the same perturbation.

  15. Generation of continuous-wave terahertz radiation using a two-mode titanium sapphire laser containing an intracavity Fabry-Perot etalon

    NASA Astrophysics Data System (ADS)

    Stone, Michael R.; Naftaly, Mira; Miles, Robert E.; Mayorga, Ivan C.; Malcoci, Andrei; Mikulics, Martin

    2005-05-01

    Continuous-wave terahertz (THz) radiation was generated by photomixing two modes of a titanium sapphire laser. The laser was induced to oscillate on two modes by placing a Fabry-Perot etalon in the laser resonator. The frequency of terahertz radiation, which was equal to the difference frequency of the two modes, was varied by adjusting the free spectral range (FSR) of the etalon. Photomixing was performed by logarithmic spiral antennas fabricated on low-temperature-grown GaAs; and the emitted THz radiation was characterized. The THz power, measured by a Golay cell, was 1μW at 0.3THz and 0.7μW at 0.5THz. The THz frequency, as determined by a Fourier transform interferometer, was seen to correspond to the etalon FSR. The current-voltage characteristics of photomixers were also determined, and photocurrent modulation was observed by the autocorrelation of the laser beam.

  16. Anaerobic digestion of solid agroindustrial waste in semi-continuous mode: Evaluation of mono-digestion and co-digestion systems.

    PubMed

    Pellera, Frantseska-Maria; Gidarakos, Evangelos

    2017-10-01

    The present study aimed at investigating the anaerobic digestion of four agroindustrial waste, namely cotton gin waste, winery waste, olive pomace and juice industry waste, in semi-continuous mode, conducting mono-digestion and co-digestion assays, using an artificial organic fraction sample as co-substrate. These assays were divided into two groups, in which different conditions were applied. Group I investigated the variation in two operational parameters, i.e. the organic loading rate (OLR) and the hydraulic retention time (HRT), while in Group II, the assays were fed with different substrates in a sequential order. Results showed more elevated specific methane yields for co-digestion assays compared with mono-digestion assays. Maximum yields were achieved at an OLR of 1.0gVS/(L·d) and a HRT reduced to half of the initial. Further reduction of the HRT coupled to an increase of the OLR generally caused a significant decrease of specific methane yields, as well as one case of severe overloading, i.e. the mono-digestion of juice industry waste, which resulted in instability and ultimately system failure. Sequential feeding with different substrates led to a more equilibrated operation, especially for co-digestion systems, with higher specific methane yields being observed during the phases corresponding to winery waste and juice industry waste substrates. Overall more positive results were obtained in the cases in which the latter substrates were fed to the reactors at process startup. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Poster - Thur Eve - 43: Is faster always better? An evaluation of frame rate effects on continuous acquisition mode EPID imaging for dose verification.

    PubMed

    Peca, S; Granville, D; Brown, D

    2012-07-01

    As radiotherapy moves towards intensity modulated arc therapy (arc-IMRT), there is a need for electronic portal imaging (EPID) to move towards continuous acquisition (cine) mode for dosimetric verification purposes. However, as the EPID resolution and frame rate (fps) increase, so does the computational burden of image processing. We investigated the reliability of cine mode EPID imaging in IMRT as a function of frame rate. We acquired EPID images continuously while running an IMRT plan (6MV photons, 150MU, dose rate = 300MU/min) with frame rates ranging from 1-12 fps, as well as a single integrated mode image. Each cine dataset was then averaged to form a single image, which was compared with the integrated mode image by means of a pixel-by-pixel absolute value subtraction. Although a greater frame rate gave better agreement with the integrated mode image in all cases, the relative benefit diminished with increasing frame rate. In particular, for the IMRT plan delivered, there was little benefit of imaging faster than 6 fps, and virtually no benefit in increasing from 9 to 12 fps. In contrast, 12 fps produces twice the number of images as 6 fps which significantly increases the image processing and data storage burdens. Increasing frame rate in cine mode EPID imaging may be beneficial in some cases, but there is likely a threshold level above which no relevant additional information is obtained. Further research to determine the ideal frame rate for any particular IMRT or arc-IMRT plan is warranted. © 2012 American Association of Physicists in Medicine.

  18. Wide range local resistance imaging on fragile materials by conducting probe atomic force microscopy in intermittent contact mode

    SciTech Connect

    Vecchiola, Aymeric; Chrétien, Pascal; Schneegans, Olivier; Mencaraglia, Denis; Houzé, Frédéric; Delprat, Sophie; Bouzehouane, Karim; Seneor, Pierre; Mattana, Richard; Tatay, Sergio; Geffroy, Bernard; and others

    2016-06-13

    An imaging technique associating a slowly intermittent contact mode of atomic force microscopy (AFM) with a home-made multi-purpose resistance sensing device is presented. It aims at extending the widespread resistance measurements classically operated in contact mode AFM to broaden their application fields to soft materials (molecular electronics, biology) and fragile or weakly anchored nano-objects, for which nanoscale electrical characterization is highly demanded and often proves to be a challenging task in contact mode. Compared with the state of the art concerning less aggressive solutions for AFM electrical imaging, our technique brings a significantly wider range of resistance measurement (over 10 decades) without any manual switching, which is a major advantage for the characterization of materials with large on-sample resistance variations. After describing the basics of the set-up, we report on preliminary investigations focused on academic samples of self-assembled monolayers with various thicknesses as a demonstrator of the imaging capabilities of our instrument, from qualitative and semi-quantitative viewpoints. Then two application examples are presented, regarding an organic photovoltaic thin film and an array of individual vertical carbon nanotubes. Both attest the relevance of the technique for the control and optimization of technological processes.

  19. Wide range local resistance imaging on fragile materials by conducting probe atomic force microscopy in intermittent contact mode

    NASA Astrophysics Data System (ADS)

    Vecchiola, Aymeric; Chrétien, Pascal; Delprat, Sophie; Bouzehouane, Karim; Schneegans, Olivier; Seneor, Pierre; Mattana, Richard; Tatay, Sergio; Geffroy, Bernard; Bonnassieux, Yvan; Mencaraglia, Denis; Houzé, Frédéric

    2016-06-01

    An imaging technique associating a slowly intermittent contact mode of atomic force microscopy (AFM) with a home-made multi-purpose resistance sensing device is presented. It aims at extending the widespread resistance measurements classically operated in contact mode AFM to broaden their application fields to soft materials (molecular electronics, biology) and fragile or weakly anchored nano-objects, for which nanoscale electrical characterization is highly demanded and often proves to be a challenging task in contact mode. Compared with the state of the art concerning less aggressive solutions for AFM electrical imaging, our technique brings a significantly wider range of resistance measurement (over 10 decades) without any manual switching, which is a major advantage for the characterization of materials with large on-sample resistance variations. After describing the basics of the set-up, we report on preliminary investigations focused on academic samples of self-assembled monolayers with various thicknesses as a demonstrator of the imaging capabilities of our instrument, from qualitative and semi-quantitative viewpoints. Then two application examples are presented, regarding an organic photovoltaic thin film and an array of individual vertical carbon nanotubes. Both attest the relevance of the technique for the control and optimization of technological processes.

  20. 20 CFR 220.186 - When and how often the Board will conduct a continuing disability review.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... the annuitant's disability continues. (This could happen when, for example, an advance in medical technology, such as improved treatment for Alzheimer's disease or a change in vocational therapy or... of trial work; (5) Substantial earnings are reported to the annuitant's wage record; (6) The...

  1. 20 CFR 220.186 - When and how often the Board will conduct a continuing disability review.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... the annuitant's disability continues. (This could happen when, for example, an advance in medical technology, such as improved treatment for Alzheimer's disease or a change in vocational therapy or... of trial work; (5) Substantial earnings are reported to the annuitant's wage record; (6) The...

  2. 20 CFR 220.186 - When and how often the Board will conduct a continuing disability review.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... the annuitant's disability continues. (This could happen when, for example, an advance in medical technology, such as improved treatment for Alzheimer's disease or a change in vocational therapy or... of trial work; (5) Substantial earnings are reported to the annuitant's wage record; (6) The...

  3. 20 CFR 220.186 - When and how often the Board will conduct a continuing disability review.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... the annuitant's disability continues. (This could happen when, for example, an advance in medical technology, such as improved treatment for Alzheimer's disease or a change in vocational therapy or... of trial work; (5) Substantial earnings are reported to the annuitant's wage record; (6) The...

  4. 20 CFR 220.186 - When and how often the Board will conduct a continuing disability review.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... the annuitant's disability continues. (This could happen when, for example, an advance in medical technology, such as improved treatment for Alzheimer's disease or a change in vocational therapy or... of trial work; (5) Substantial earnings are reported to the annuitant's wage record; (6) The...

  5. Continuous variable methods in relativistic quantum information: characterization of quantum and classical correlations of scalar field modes in noninertial frames

    NASA Astrophysics Data System (ADS)

    Adesso, Gerardo; Ragy, Sammy; Girolami, Davide

    2012-11-01

    We review a recently introduced unified approach to the analytical quantification of correlations in Gaussian states of bosonic scalar fields by means of Rényi-2 entropy. This allows us to obtain handy formulae for classical, quantum, total correlations, as well as bipartite and multipartite entanglement. We apply our techniques to the study of correlations between two modes of a scalar field as described by observers in different states of motion. When one or both observers are in uniform acceleration, the quantum and classical correlations are degraded differently by the Unruh effect, depending on which mode is detected. Residual quantum correlations, in the form of quantum discord without entanglement, may survive in the limit of an infinitely accelerated observer Rob, provided they are revealed in a measurement performed by the inertial Alice.

  6. Mode-locking operation of quasi-continuous diode pumped TGT-grown Nd,Y-codoped:SrF2 crystal

    NASA Astrophysics Data System (ADS)

    Jelínek, Michal; Kubeček, Václav; Su, Liangbi; Jiang, Dapeng; Ma, Fengkai; Zhang, Qian; Cao, Yuexin; Xu, Jun

    2015-01-01

    Fluoride-type crystals (CaF2, SrF2) doped with neodymium Nd3+ present interesting alternative as a laser active media for the diode-pumped mode-locked laser systems mainly because of their broad emission spectra as well as longer fluorescence lifetime in comparison with well-known materials as Nd:YAG or Nd:YVO4. In comparison with Nd:glass active material, SrF2 and CaF2 have better thermal conductivity. In spite of the thermal conductivity decreases with doping concentration, these crystal might be interesting alternative for the Nd:glass mode-locked laser systems. In this contribution we present the first results of the Nd,Y:SrF2 mode-locked laser diode-pumped at 796nm. Mode-locking operation using SESAM was successfully achieved in the pulsed pumping regime (pulse-duration 1.5 ms, frequency 10 Hz) with the overall average output power of 2.3 mW (corresponding to the power amplitude of 153 mW) in one output beam at the wavelength of ~1055 nm. The actual pulse-duration was 87 ps.

  7. A parametric study for the generation of ion Bernstein modes from a discrete spectrum to a continuous one in the inner magnetosphere. I. Linear theory

    NASA Astrophysics Data System (ADS)

    Sun, Jicheng; Gao, Xinliang; Chen, Lunjin; Lu, Quanming; Tao, Xin; Wang, Shui

    2016-02-01

    Ion Bernstein modes, also known as magnetosonic waves in the magnetospheric community, are considered to play an important role in radiation belt electron acceleration. The detailed properties of perpendicular magnetosonic waves excited in the inner magnetosphere by a tenuous proton ring distribution are investigated in a two series paper with a combination of the linear theory and one-dimensional particle-in-cell simulations. Here, in this paper, we study the properties of the excited magnetosonic waves under different plasma conditions with the linear theory. When the proton to electron mass ratio or the ratio of the light speed to the Alfven speed is small, the excited magnetosonic waves are prone to having a discrete spectrum with only several wave modes. With the increase of the proton to electron mass ratio or the ratio of the light speed to the Alfven speed, the lower hybrid frequency also increases, which leads to the increase of both the number and frequency of the excited wave modes. Meanwhile, the growth rate of these wave modes also increases. When the proton to electron mass ratio or the ratio of the light speed to the Alfven speed is sufficiently large, the spectrum of the excited magnetic waves becomes continuous due to the overlapping of the adjacent wave modes. The increase of the density of the protons with the ring distribution can also result in the increase of the growth rate, which may also change the discrete spectrum of the excited waves to a continuous one, while the increase of the ring velocity of the tenuous proton ring distribution leads to a broader spectrum, but with a smaller growth rate.

  8. Duration of untreated psychosis: are we ignoring the mode of initial development?. An extensive naturalistic case study of phenomenal continuity in first-episode schizophrenia.

    PubMed

    Møller, P

    2001-01-01

    Duration of untreated psychosis (DUP) might affect the course and treatment outcome in schizophrenia significantly. Looking for potential determinants of DUP, researchers have mostly assessed the initial untreated psychosis in terms of plain duration, not developmental content. The present study provides empirical contributions to the discussion of phenomenal continuity throughout the entire untreated illness by pointing out continuous trajectories from prodrome to psychosis. In a series of 19 first-episode DSM-IV schizophrenia patients, we explore prodromal and untreated psychotic phenomena, and the data indicate that symptoms considered intrinsic to core psychosis phenomenology had attenuated antecedents in the prodromes, increasing continuously until treatment, whereas symptoms considered not intrinsic to core psychosis were characterized by fluctuations. Mode of initial psychosis development is proposed as a tentatively informative concept, comprising duration and content aspects of the initial prodrome and untreated psychosis.

  9. Optically-induced switching between mode-locked and unmode-locked continuous wave regimes of a femtosecond Cr4+:forsterite laser

    NASA Astrophysics Data System (ADS)

    Walsh, D. A.; Crombie, C. E.; Sibbett, W.; Brown, C. T. A.; Savitski, V. G.; Burns, D.; Calvez, S.

    2012-06-01

    The ability to control the temporal output from a femtosecond laser can enable the same laser to be used for multiple functions, for example, the laser used in an optical tweezers system could be used as a constant-intensity source to trap a biological cell and then be temporarily switched to mode-locked operation to effect photoporation. Here, we report the rapid switching of a Cr4+:forsterite laser between mode-locked and unmode-locked continuous wave (CW) regimes via the optical pumping of an intracavity SESAM element. Mode-locking of the laser was initiated by an intracavity quantum well (GaInAsN) SESAM having an anti-resonant design (ΔR~0.3%, λPL~1310nm) that yielded transform-limited 89fs pulses centered around 1296nm with a repetition rate of 162MHz at an average power of 64mW. Upon excitation of the SESAM with 600mW of extra-cavity power from an 808nm semiconductor diode laser, switching could be induced between the unmode-locked and mode-locked regimes. Transitions free of Q-switching or relaxation oscillations were observed with <200μs switching times for both for the initiation and cessation of mode-locking. Periods of mode-locked operation of custom duration could be produced by appropriate control of the SESAM pump diode enabling the generation of bursts of pulses as short as 400μs. Switching was confirmed to originate from local pump-induced heating of the SESAM by observing the laser going through identical regime switching when the chip temperature of the 'unpumped' SESAM was raised by ~20°C.

  10. Study of collective radial breathing-like modes in double-walled carbon nanotubes: combination of continuous two-dimensional membrane theory and Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Levshov, Dmitry I.; Avramenko, Marina V.; Than, Xuan-Tinh; Michel, Thierry; Arenal, Raul; Paillet, Matthieu; Rybkovskiy, Dmitry V.; Osadchy, Alexander V.; Rochal, Sergei B.; Yuzyuk, Yuri I.; Sauvajol, Jean-Louis

    2016-01-01

    Radial breathing modes (RBMs) are widely used for the atomic structure characterization and index assignment of single-walled carbon nanotubes (SWNTs) from resonant Raman spectroscopy. However, for double-walled carbon nanotubes (DWNTs), the use of conventional ωRBM(d) formulas is complicated due to the van der Waals interaction between the layers, which strongly affects the frequencies of radial modes and leads to new collective vibrations. This paper presents an alternative way to theoretically study the collective radial breathing-like modes (RBLMs) of DWNTs and to account for interlayer interaction, namely the continuous two-dimensional membrane theory. We obtain an analytical ωRBLM(do,di) relation, being the equivalent of the conventional ωRBM(d) expressions, established for SWNTs. We compare our theoretical predictions with Raman data, measured on individual index-identified suspended DWNTs, and find a good agreement between experiment and theory. Moreover, we show that the interlayer coupling in individual DWNTs strongly depends on the interlayer distance, which is manifested in the frequency shifts of the RBLMs with respect to the RBMs of the individual inner and outer tubes. In terms of characterization, this means that the combination of Raman spectroscopy data and predictions of continuous membrane theory may give additional criteria for the index identification of DWNTs, namely the interlayer distance.

  11. Finite Time Fault Tolerant Control for Robot Manipulators Using Time Delay Estimation and Continuous Nonsingular Fast Terminal Sliding Mode Control.

    PubMed

    Van, Mien; Ge, Shuzhi Sam; Ren, Hongliang

    2016-04-28

    In this paper, a novel finite time fault tolerant control (FTC) is proposed for uncertain robot manipulators with actuator faults. First, a finite time passive FTC (PFTC) based on a robust nonsingular fast terminal sliding mode control (NFTSMC) is investigated. Be analyzed for addressing the disadvantages of the PFTC, an AFTC are then investigated by combining NFTSMC with a simple fault diagnosis scheme. In this scheme, an online fault estimation algorithm based on time delay estimation (TDE) is proposed to approximate actuator faults. The estimated fault information is used to detect, isolate, and accommodate the effect of the faults in the system. Then, a robust AFTC law is established by combining the obtained fault information and a robust NFTSMC. Finally, a high-order sliding mode (HOSM) control based on super-twisting algorithm is employed to eliminate the chattering. In comparison to the PFTC and other state-of-the-art approaches, the proposed AFTC scheme possess several advantages such as high precision, strong robustness, no singularity, less chattering, and fast finite-time convergence due to the combined NFTSMC and HOSM control, and requires no prior knowledge of the fault due to TDE-based fault estimation. Finally, simulation results are obtained to verify the effectiveness of the proposed strategy.

  12. Water-jet dissector for endoscopic submucosal dissection in an animal study: outcomes of the continuous and pulsed modes.

    PubMed

    Lepilliez, Vincent; Robles-Medranda, Carlos; Ciocirlan, Mihai; Lukashok, Hannah; Chemali, Marwan; Langonnet, Stephan; Chesnais, Sabrina; Hervieu, Valerie; Ponchon, Thierry

    2013-08-01

    Endoscopic submucosal dissection (ESD) allows en bloc resection of early neoplastic lesions of gastrointestinal tract. Lesions are lifted by submucosal fluid injection before circumferential incision and dissection. High-pressure fluid injection using water jet (WJ) technology is already used for lifting and dissection in surgery. The study was designed to assess WJ for ESD submucosal lifting and dissection. An experimental, randomized comparative, "in vivo" nonsurvival animal study on 12 pigs was designed. Stomach mucosal areas were delineated and resected using three ESD techniques: technique A-syringe injection and IT knife dissection; technique B-WJ continuous injection and IT knife dissection; technique C-WJ injection and WJ pulsed dissection. Injection and dissection speeds and complications rates were assessed. Water jet continuous injection is faster than syringe injection (B faster than A, p = 0.001 and B nonsignificantly faster than C, p = 0.06). IT knife dissection is significantly faster after WJ continuous injection (B faster than A, p = 0.003). WJ pulsed dissection is significantly slower than IT knife dissection (C slower than A and B, both p < 0.001). The overall procedure speed was significantly higher and the immediate bleedings rate was significantly lower for technique B than A and C (overall procedure speed p = 0.001, immediate bleedings p = 0.032 and 0.038 respectively). There were no perforations with any technique. Water jet fluid continuous injection speeds up ESD, whereas pulsed WJ dissection does not.

  13. Continuous-wave 532 nm pumped MgO:PPLN optical parametric oscillator with external power regulation and spatial mode filtering.

    PubMed

    Lee, Dong-Hoon; Kim, Seung Kwan; Park, Seung-Nam; Park, Hee Su; Lee, Jae Yong; Choi, Sang-Kyung

    2009-01-01

    We report a continuous-wave (CW) optical parametric oscillator (OPO) based on a MgO-doped periodically poled LiNbO(3) (MgO:PPLN) crystal. The 532 nm pump generates coherent radiation that is tunable from 800 to 920 nm for the signal and from 1250 to 1580 nm for the idler, respectively. The OPO output power exhibits a slowly varying instability that we attribute to a thermal effect induced by the pump. This instability is truncated by means of a low-pass servo that includes a single-mode fiber that filters the beam into a single spatial mode. The resulting output characteristics are promising for radiometric applications in the near infrared including most fiber-optic communication bands.

  14. Continuous pH, electrical conductivity and temperature measurement at Plynlimon: towards an integrated, reliable and low maintenance instrument system

    NASA Astrophysics Data System (ADS)

    Hodgson, P.; Evans, J. G.

    Water quality data for the Nant Tanilwyth stream, Plynlimon (an acidic upland stream, the waters of which are of such low ionic strength that measurement is difficult), has been recorded using a new integrated field instrument system. The negligible drift of the pH electrode allows the system to operate for extended periods (months) without re-calibration, whilst maintaining a standard deviation of 0.19 pH units between its readings and laboratory reference measurements. Conductivity measurements, although within the sensor manufacturer's specification, did not provide meaningful readings at conductivities below 50 μS cm-1. Using the pH data as a surrogate tracer, a high temporal resolution estimate of the stream dynamics, in terms of the contributions of groundwater and soil-water is presented; the dependence of these relative proportions on instantaneous flow and antecedent conditions is shown. It is concluded that, whilst improvements in instrumentation have been made, greater accuracy is still desirable for some scientific applications and ways forward are described.

  15. All-diode-pumped quasi-continuous burst-mode laser for extended high-speed planar imaging.

    PubMed

    Slipchenko, Mikhail N; Miller, Joseph D; Roy, Sukesh; Gord, James R; Meyer, Terrence R

    2013-01-14

    An all-diode-pumped, multistage Nd:YAG amplifier is investigated as a means of extending the duration of high-power, burst-mode laser pulse sequences to an unprecedented 30 ms or more. The laser generates 120 mJ per pulse at 1064.3 nm with a repetition rate of 10 kHz, which is sufficient for a wide range of planar laser diagnostics based on fluorescence, Raman scattering, and Rayleigh scattering, among others. The utility of the technique is evaluated for image sequences of formaldehyde fluorescence in a lifted methane-air diffusion flame. The advantages and limitations of diode pumping are discussed, along with long-pulse diode-bar performance characteristics to guide future designs.

  16. Aharonov-Bohm conductance through a single-channel quantum ring: persistent-current blockade and zero-mode dephasing.

    PubMed

    Dmitriev, A P; Gornyi, I V; Kachorovskii, V Yu; Polyakov, D G

    2010-07-16

    We study the effect of electron-electron interaction on transport through a tunnel-coupled single-channel ring. We find that the conductance as a function of magnetic flux shows a series of interaction-induced resonances that survive thermal averaging. The period of the series is given by the interaction strength α. The physics behind this behavior is the blocking of the tunneling current by the circular current. The main mechanism of dephasing is due to circular-current fluctuations. The dephasing rate is proportional to the tunneling rate and does not depend on α.

  17. Effect of fed-batch vs. continuous mode of operation on microbial fuel cell performance treating biorefinery wastewater

    DOE PAGES

    Pannell, Tyler C.; Goud, R. Kannaiah; Schell, Daniel J.; ...

    2016-05-01

    Bioelectrochemical systems have been shown to treat low-value biorefinery streams while recovering energy, however, low current densities and anode conversion efficiencies (ACE) limit their application. A bioanode was developed via enrichment of electroactive biofilm under fed-batch and continuous feeding conditions using corn stover-derived waste stream. The continuously-fed MFC exhibited a current density of 5.8±0.06 A/m2 and an ACE of 39%±4. The fed-batch MFC achieved a similar current density and an ACE of 19.2%, however, its performance dropped after 36 days of operation to 1.1 A/m2 and 0.5%, respectively. In comparison, the ACE of the continuously-fed MFC remained stable achieving anmore » ACE of 30% ± 3 after 48 days of operation. An MFC treating a biorefinery stream post fuel separation achieved a current density of 10.7±0.1 A/m2 and an ACE of 57% ± 9 at an organic loading of 12.5 g COD/L-day. Characterization of the microbial communities indicate higher abundance of Firmicutes and Proteobacteria and lower abundance of Bacteriodetes and a higher level of Geobacter spp. (1.4% vs. 0.2%) in continuously-fed MFC vs. fed-batch MFC. Finally, the results demonstrate that limiting substrate to the equivalent maximum current that the anode can generate, maintains MFC performance over a long term for high strength wastewaters, such as those generated in the biorefinery.« less

  18. Effect of fed-batch vs. continuous mode of operation on microbial fuel cell performance treating biorefinery wastewater

    SciTech Connect

    Pannell, Tyler C.; Goud, R. Kannaiah; Schell, Daniel J.; Borole, Abhijeet P.

    2016-05-01

    Bioelectrochemical systems have been shown to treat low-value biorefinery streams while recovering energy, however, low current densities and anode conversion efficiencies (ACE) limit their application. A bioanode was developed via enrichment of electroactive biofilm under fed-batch and continuous feeding conditions using corn stover-derived waste stream. The continuously-fed MFC exhibited a current density of 5.8±0.06 A/m2 and an ACE of 39%±4. The fed-batch MFC achieved a similar current density and an ACE of 19.2%, however, its performance dropped after 36 days of operation to 1.1 A/m2 and 0.5%, respectively. In comparison, the ACE of the continuously-fed MFC remained stable achieving an ACE of 30% ± 3 after 48 days of operation. An MFC treating a biorefinery stream post fuel separation achieved a current density of 10.7±0.1 A/m2 and an ACE of 57% ± 9 at an organic loading of 12.5 g COD/L-day. Characterization of the microbial communities indicate higher abundance of Firmicutes and Proteobacteria and lower abundance of Bacteriodetes and a higher level of Geobacter spp. (1.4% vs. 0.2%) in continuously-fed MFC vs. fed-batch MFC. Finally, the results demonstrate that limiting substrate to the equivalent maximum current that the anode can generate, maintains MFC performance over a long term for high strength wastewaters, such as those generated in the biorefinery.

  19. Effect of fed-batch vs. continuous mode of operation on microbial fuel cell performance treating biorefinery wastewater

    SciTech Connect

    Pannell, Tyler C.; Goud, R. Kannaiah; Schell, Daniel J.; Borole, Abhijeet P.

    2016-05-01

    Bioelectrochemical systems have been shown to treat low-value biorefinery streams while recovering energy, however, low current densities and anode conversion efficiencies (ACE) limit their application. A bioanode was developed via enrichment of electroactive biofilm under fed-batch and continuous feeding conditions using corn stover-derived waste stream. The continuously-fed MFC exhibited a current density of 5.8±0.06 A/m2 and an ACE of 39%±4. The fed-batch MFC achieved a similar current density and an ACE of 19.2%, however, its performance dropped after 36 days of operation to 1.1 A/m2 and 0.5%, respectively. In comparison, the ACE of the continuously-fed MFC remained stable achieving an ACE of 30% ± 3 after 48 days of operation. An MFC treating a biorefinery stream post fuel separation achieved a current density of 10.7±0.1 A/m2 and an ACE of 57% ± 9 at an organic loading of 12.5 g COD/L-day. Characterization of the microbial communities indicate higher abundance of Firmicutes and Proteobacteria and lower abundance of Bacteriodetes and a higher level of Geobacter spp. (1.4% vs. 0.2%) in continuously-fed MFC vs. fed-batch MFC. Finally, the results demonstrate that limiting substrate to the equivalent maximum current that the anode can generate, maintains MFC performance over a long term for high strength wastewaters, such as those generated in the biorefinery.

  20. Effect of Fed-Batch vs. Continuous Mode of Operation on Microbial Fuel Cell Performance Treating Biorefinery Wastewater

    SciTech Connect

    Pannell, Tyler C.; Goud, R. Kannaiah; Schell, Daniel J.; Borole, Abhijeet P.

    2016-12-15

    Bioelectrochemical systems have been shown to treat low-value biorefinery streams while recovering energy, however, low current densities and anode conversion efficiencies (ACE) limit their application. A bioanode was developed via enrichment of electroactive biofilm under fed-batch and continuous feeding conditions using corn stover-derived waste stream. The continuously-fed MFC exhibited a current density of 5.8 +/- 0.06 A/m2 and an ACE of 39% +/- 4. The fed-batch MFC achieved a similar current density and an ACE of 19.2%, however, its performance dropped after 36 days of operation to 1.1 A/m2 and 0.5%, respectively. In comparison, the ACE of the continuously-fed MFC remained stable achieving an ACE of 30% +/- 3 after 48 days of operation. An MFC treating a biorefinery stream post fuel separation achieved a current density of 10.7 +/- 0.1 A/m2 and an ACE of 57% +/- 9 at an organic loading of 12.5 g COD/L-day. Characterization of the microbial communities indicate higher abundance of Firmicutes and Proteobacteria and lower abundance of Bacteriodetes and a higher level of Geobacter spp. (1.4% vs. 0.2%) in continuously-fed MFC vs. fed-batch MFC. The results demonstrate that limiting substrate to the equivalent maximum current that the anode can generate, maintains MFC performance over a long term for high strength wastewaters, such as those generated in the biorefinery.

  1. Effects of 2450 MHz continuous wave microwave radiation and isothermal conduction on canine platelet aggregometry, survival and margination

    SciTech Connect

    Bushberg, J.T.

    1981-01-01

    The effect of 2450 MHz microwave radiation and isothermal conduction ex vivo exposures on canine platelets was analyzed in vitro by studying adenosine-5'-diphosphate activated aggregation and in vivo by studying the survival, distribution and physiological integrity of reinfused autologous Indium-111 labeled platelets. Platelet rich plasma (PRP) from eight healthy dogs was subjected to microwave irradiation at 10 MW/cm/sup 2/ and at 50 MW/cm/sup 2/ for 10, 100, 600, 900, 1800 seconds and at 100 MW/cm/sup 2/ for 10, 100, and 600 seconds. Aggregometry analysis was performed immediately after exposure and 10 minutes post-exposure. No significant perturbations were observed following microwave exposure of 10 MW/cm/sup 2/. At higher power densities six specific types of aggregation phenomena were demonstrated: (1) Hyperaggregation, (2) Decreased Velocity Reduced Hyperaggregation, (3) Recovery, (4) Decreased Velocity Delayed Hyperaggregation, (5) Reversible Afunctionality, and (6) Irreversible Afunctionality. The absence of equivalent aggregation responses with isothermal conduction heating (extraisothermal effects) was attributed to differences in heating rate and not to nonthermal microwave-specific effects. Scintigraphic and survival kinetic studies were performed following power density/exposure time combinations. PRP samples I and IV displayed normal survival half-times; however, exposure I resulted in a depressed 15-minute post-reinfusion circulating percentage (CP/sub 15/) of 29% compared to 61% for the control sample. Exposure of groups II and III resulted in a dramatic reduction in the CP/sub 15/ (i.e., 18% and 1.3% respectively) and survival half-times. Margination of the labeled platelets was divided between the spleen, liver and blood pool.

  2. Heated Humidified High Flow Nasal Cannula versus Nasal Continuous Positive Airway Pressure as Primary Mode of Respiratory Support for Respiratory Distress in Preterm Infants.

    PubMed

    Hegde, Deeparaj; Mondkar, Jayashree; Panchal, Harshad; Manerkar, Swati; Jasani, Bonny; Kabra, Nandkishor

    2016-02-01

    To compare the outcomes of preterm infants with respiratory distress initiated on either Heated Humidified High Flow Nasal Cannula or Nasal Continuous Positive Airway Pressure as a primary mode of respiratory support. Prospective observational cohort study. Tertiary care level III neonatal intensive care unit. 88 preterm infants between 28 to 34 weeks of gestation with mild to moderate respiratory distress within 6 hours of birth. Eligible infants were treated either with Heated Humidified High Flow Nasal Cannula (n=46) or Nasal Continuous Positive Airway Pressure (n=42). Need for mechanical ventilation within 72 hrs of initiating support. Baseline demographic characteristics were comparable between the two groups. There was no difference in the requirement of mechanical ventilation between Heated Humidified High Flow Nasal Cannula (19.5%) and Nasal Continuous Positive Airway Pressure (26.2%) groups [RD-0.74 (95% CI 0.34-1.62; P =0.46)]. Moderate or severe nasal trauma occurred less frequently with Heated Humidified High Flow Nasal Cannula (10.9%) in comparison to Nasal Continuous Positive Airway Pressure (40.5%) (P= 0.004). Heated Humidified High Flow Nasal Cannula was comparable to Nasal Continuous Positive Airway Pressure as a primary respiratory support for preterm infants with respiratory distress, with lesser incidence of nasal trauma.

  3. Scale-up of counter-current chromatography: demonstration of predictable isocratic and quasi-continuous operating modes from the test tube to pilot/process scale.

    PubMed

    Sutherland, Ian; Hewitson, Peter; Ignatova, Svetlana

    2009-12-11

    Predictable scale-up from test tube derived distribution ratios and analytical-scale sample loading optimisation is demonstrated using a model sample system of benzyl alcohol and p-cresol in a heptane:ethyl acetate:methanol:water phase system with the new 18 L Maxi counter-current chromatography centrifuge. The versatility of having a liquid stationary phase with its high loading capacity and flexible operating modes is demonstrated at two different scales by separating and concentrating target compounds using a mixture of caffeine, vanillin, naringenin and carvone using a quasi-continuous technique called intermittent counter-current extraction.

  4. Effects of Na(+) on the predominant K(+) channel in the tonoplast of Chara: decrease of conductance by blocks in 100 nanosecond range and induction of oligo- or poly-subconductance gating modes.

    PubMed

    Weise, R; Gradmann, D

    2000-05-15

    We present three mechanisms by which Na(+) inhibits the open channel currents of the predominant K(+) channel in the tonoplast of Chara corallina: (i) Fast block, i.e., short (100 ns range) interruptions of the open channel current which are determined by open channel noise analysis, (ii): Oligo-subconductance mode, i.e., a gating mode which occurs preferentially in the presence of Na(+); this mode comprises a discrete number (here 3) of open states with smaller conductances than normal, and (iii): Polysubconductance mode, i.e., a gating mode with a nondiscrete, large number (>30) of states with smaller conductances than the main open channel conductance. This novel mode has also been observed only in the presence of Na(+).

  5. A monitor for continuous measurement of temperature, pH, and conductance of wet precipitation: Preliminary results from the Adirondack Mountains, New York

    USGS Publications Warehouse

    Johnsson, P.A.; Reddy, M.M.

    1990-01-01

    This report describes a continuous wet-only precipitation monitor designed by the U.S. Geological Survey to record variations in rainfall temperature, pH, and specific conductance at 1-min intervals over the course of storms. Initial sampling in the Adirondack Mountains showed that rainfall acidity varied over the course of summer storms, with low initial pH values increasing as storm intensity increased.This report describes a continuous wet-only precipitation monitor designed by the U.S. Geological Survey to record variations in rainfall temperature, pH, and specific conductance at 1-min intervals over the course of storms. Initial sampling in the Adirondack Mountains showed that rainfall acidity varied over the course of summer storms, with low initial pH values increasing as storm intensity increased.

  6. Low-cost, disposable microfluidics device for blood plasma extraction using continuously alternating paramagnetic and diamagnetic capture modes

    PubMed Central

    Kim, Pilkee; Ong, Eng Hui; Yoon, Yong-Jin; Ng, Sum Huan Gary; Puttachat, Khuntontong

    2016-01-01

    Blood plasma contains biomarkers and substances that indicate the physiological state of an organism, and it can be used to diagnose various diseases or body condition. To improve the accuracy of diagnostic test, it is required to obtain the high purity of blood plasma. This paper presents a low-cost, disposable microfluidics device for blood plasma extraction using magnetophoretic behaviors of blood cells. This device uses alternating magnetophoretic capture modes to trap and separate paramagnetic and diamagnetic cells away from blood plasma. The device system is composed of two parts, a disposable microfluidics chip and a non-disposable (reusable) magnetic field source. Such modularized device helps the structure of the disposable part dramatically simplified, which is beneficial for low-cost mass production. A series of numerical simulation and parametric study have been performed to describe the mechanism of blood cell separation in the microchannel, and the results are discussed. Furthermore, experimental feasibility test has been carried out in order to demonstrate the blood plasma extraction process of the proposed device. In this experiment, pure blood plasma has been successfully extracted with yield of 21.933% from 75 μl 1:10 dilution of deoxygenated blood. PMID:27042252

  7. Low-cost, disposable microfluidics device for blood plasma extraction using continuously alternating paramagnetic and diamagnetic capture modes.

    PubMed

    Kim, Pilkee; Ong, Eng Hui; Li, King Ho Holden; Yoon, Yong-Jin; Ng, Sum Huan Gary; Puttachat, Khuntontong

    2016-03-01

    Blood plasma contains biomarkers and substances that indicate the physiological state of an organism, and it can be used to diagnose various diseases or body condition. To improve the accuracy of diagnostic test, it is required to obtain the high purity of blood plasma. This paper presents a low-cost, disposable microfluidics device for blood plasma extraction using magnetophoretic behaviors of blood cells. This device uses alternating magnetophoretic capture modes to trap and separate paramagnetic and diamagnetic cells away from blood plasma. The device system is composed of two parts, a disposable microfluidics chip and a non-disposable (reusable) magnetic field source. Such modularized device helps the structure of the disposable part dramatically simplified, which is beneficial for low-cost mass production. A series of numerical simulation and parametric study have been performed to describe the mechanism of blood cell separation in the microchannel, and the results are discussed. Furthermore, experimental feasibility test has been carried out in order to demonstrate the blood plasma extraction process of the proposed device. In this experiment, pure blood plasma has been successfully extracted with yield of 21.933% from 75 μl 1:10 dilution of deoxygenated blood.

  8. Genomic and Proteomic Evaluation of Tissue Quality of Porcine Wounds Treated With Negative Pressure Wound Therapy in Continuous, Noncontinuous, and Instillation Modes

    PubMed Central

    Lessing, M. Christian

    2014-01-01

    Objective: Negative pressure wound therapy with instillation (NPWTi-d) combines NPWT with automated delivery and removal of topical wound treatment solutions. This porcine study compared genomic and proteomic responses of wounds treated with NPWTi-d with saline to wounds treated with NPWT in continuous and noncontinuous modes. Methods: Full-thickness porcine dorsal excisional wounds were treated with continuous NPWT, intermittent NPWT, dynamic NPWT, or NPWTi-d with saline (n = 10 wounds per group). On day 7, animals were euthanized and tissues collected. Real-time quantitative polymerase chain reaction arrays profiled expression of 84 genes including extracellular matrix remodeling factors, inflammatory cytokines and chemokines, and growth factors and major signaling molecules. Concentrations of proteins associated with angiogenesis, extracellular matrix components, and cellular energetics were analyzed via enzyme-linked immunosorbent assays. Results: Gene expression profiles for NPWTi-d with saline and continuous NPWT were similar. There were 5 upregulated and 18 downregulated genes overexpressed in NPWTi-d compared to NPWT wounds. Protein content was comparable in all treatment groups and similar to unwounded tissue. Conclusions: Previous preclinical studies have reported an increased rate of granulation tissue formation with NPWTi-d with saline compared to NPWT in continuous and noncontinuous modes. This evaluation of gene and protein expression suggests that the granulation tissue in these wounds has a similar quality. This first look at the differences in gene expression, particularly in genes related to remodeling, cell adhesion, inflammation, and growth factors, could help to clarify the observed differences in granulation rates. PMID:25525482

  9. Scale-up from shake flasks to fermenters in batch and continuous mode with Corynebacterium glutamicum on lactic acid based on oxygen transfer and pH.

    PubMed

    Seletzky, Juri M; Noak, Ute; Fricke, Jens; Welk, Eike; Eberhard, Werner; Knocke, Christof; Büchs, Jochen

    2007-11-01

    Scale-up from shake flasks to fermenters has been hampered by the lack of knowledge concerning the influence of operating conditions on mass transfer, hydromechanics, and power input. However, in recent years the properties of shake flasks have been described with empirical models. A practical scale-up strategy for everyday use is introduced for the scale-up of aerobic cultures from shake flasks to fermenters in batch and continuous mode. The strategy is based on empirical correlations of the volumetric mass transfer coefficient (k(L) a) and the pH. The accuracy of the empirical k(L) a correlations and the assumptions required to use these correlations for an arbitrary biological medium are discussed. To determine the optimal pH of the culture medium a simple laboratory method based on titration curves of the medium and a mechanistic pH model, which is solely based on the medium composition, is applied. The effectiveness of the scale-up strategy is demonstrated by comparing the behavior of Corynebacterium glutamicum on lactic acid in shake flasks and fermenters in batch and continuous mode. The maximum growth rate (micro(max) = 0.32 h(-1)) and the oxygen substrate coefficient (Y O2 /S= 0.0174 mol/l) of C. glutamicum on lactic acid were equal for shake flask, fermenter, batch, and continuous cultures. The biomass substrate yield was independent of the scale, but was lower in batch cultures (Y(X/S) = 0.36 g/g) than in continuous cultures (Y(X/S) = 0.45 g/g). The experimental data (biomass, respiration, pH) could be described with a simple biological model combined with a mechanistic pH model. (c) 2007 Wiley Periodicals, Inc.

  10. Liquid-phase epitaxy grown PbSnTe distributed feedback laser diodes with broad continuous single-mode tuning range

    NASA Technical Reports Server (NTRS)

    Hsieh, H.-H.; Fonstad, C. G.

    1980-01-01

    Distributed feedback (DFB) pulsed laser operation has been demonstrated in stripe geometry Pb(1-x)Sn(x)Te double-heterostructures grown by liquid-phase epitaxy. The grating structure of 0.79 micron periodicity operates in first order near 12.8 microns and was fabricated prior to the liquid-phase epitaxial growth using holographic exposure techniques. These DFB lasers had moderate thresholds, 3.6 kA/sq cm, and the output power versus current curves exhibited a sharp turn-on free of kinks. Clean, single-mode emission spectra, continuously tunable over a range in excess of 20 per cm, centered about 780 per cm (12.8 microns), and at an average rate of 1.2 per cm-K from 9 to 26 K, were observed. While weaker modes could at times be seen in the spectrum, substantially single-mode operation was obtained over the entire operating range and to over 10 times threshold.

  11. Tunable diode laser-pumped Tm,Ho:YLF laser operated in continuous-wave and Q-switched modes

    NASA Technical Reports Server (NTRS)

    Mcguckin, B. T.; Hemmati, H.; Menzies, R. T.

    1992-01-01

    Tunable continuous-wave and pulsed laser output was obtained from a Tm-sensitized Ho:YLiF4 crystal at subambient temperatures when longitudinally pumped with a diode laser array. A conversion efficiency of 42 percent and slope efficiency of approximately 60 percent relative to the absorbed pumped power have been achieved at a crystal temperature of 275 K. The emission spectrum was etalon tunable over a range of 16/cm centered at 2067 nm with fine tuning capability of the transition frequency with crystal temperature at measured rate of -0.03/cm/K. Output energies of 0.22 mJ per pulse and 22 ns pulse duration were recorded at Q-switch frequencies that correspond to an effective upper laser level lifetime of 6 ms, and a pulse energy extraction efficiency of 64 percent.

  12. Characteristic Features of the Mode Energy Estimated from Tunneling Conductance on TlBa2Ca2Cu3O8.5+δ

    NASA Astrophysics Data System (ADS)

    Sekine, Ryotaro; Denholme, Saleem J.; Tsukada, Akio; Kawashima, Susumu; Minematsu, Mitsumasa; Inose, Takashi; Mikusu, Satoshi; Tokiwa, Kazuyasu; Watanabe, Tsuneo; Miyakawa, Nobuaki

    2016-02-01

    We report the temperature dependence of tunneling conductance from 5 to 190 K for overdoped TlBa2Ca2Cu3O8.5+δ (Tl1223) with TC ˜ 112 K. The tunneling conductances exhibit clear dips at a voltage, Vdip, below TC, suggesting that the dip is of superconducting origin. Moreover, we have found that the mode energy Ω is 38 meV and independent of temperature, where Ω is defined as the difference between eVdip and the superconducting gap Δ. In addition, the temperature dependence of the tunneling dip strength is similar to that of the magnetic resonance intensity at (π ,π ) observed in inelastic neutron scattering experiments. We found that the relationship between the average mode energy bar{Ω } and Δ for Tl1223 is a common feature of Bi2Sr2CaCu2O8+δ, where bar{Ω }/Δ increases with decreasing Δ, but does not exceed 2. These characteristic features of the tunneling dips are consistent with not only those of resonance spin excitation but also pairing models in which the (π ,π ) resonance is a collective spin excitation.

  13. ZnO-PLLA Nanofiber Nanocomposite for Continuous Flow Mode Purification of Water from Cr(VI)

    PubMed Central

    Burks, T.; Akthar, F.; Saleemi, M.; Avila, M.; Kiros, Y.

    2015-01-01

    Nanomaterials of ZnO-PLLA nanofibers have been used for the adsorption of Cr(VI) as a prime step for the purification of water. The fabrication and application of the flexible ZnO-PLLA nanofiber nanocomposite as functional materials in this well-developed architecture have been achieved by growing ZnO nanorod arrays by chemical bath deposition on synthesized electrospun poly-L-lactide nanofibers. The nanocomposite material has been tested for the removal and regeneration of Cr(IV) in aqueous solution under a “continuous flow mode” by studying the effects of pH, contact time, and desorption steps. The adsorption of Cr(VI) species in solution was greatly dependent upon pH. SEM micrographs confirmed the successful fabrication of the ZnO-PLLA nanofiber nanocomposite. The adsorption and desorption of Cr(VI) species were more likely due to the electrostatic interaction between ZnO and Cr(VI) ions as a function of pH. The adsorption and desorption experiments utilizing the ZnO-PLLA nanofiber nanocomposite have appeared to be an effective nanocomposite in the removal and regeneration of Cr(VI) species. PMID:26681961

  14. Can carbon nanotube fibers achieve the ultimate conductivity?—Coupled-mode analysis for electron transport through the carbon nanotube contact

    NASA Astrophysics Data System (ADS)

    Xu, Fangbo; Sadrzadeh, Arta; Xu, Zhiping; Yakobson, Boris I.

    2013-08-01

    Recent measurements of carbon nanotube (CNT) fibers electrical conductivity still show the values lower than that of individual CNTs, by about one magnitude order. The imperfections of manufacturing process and constituent components are described as culprits. What if every segment is made perfect? In this work, we study the quantum conductance through the parallel junction of flawless armchair CNTs using tight-binding method in conjunction with non-equilibrium Green's function approach. Short-range oscillations within the long-range oscillations as well as decaying envelopes are all observed in the computed Fermi-level (low bias) conductance as a function of contact length, L. The propagation of CNTs' Bloch waves is cast in the coupled-mode formalism and helps to reveal the quantum interference nature of various behaviors of conductance. Our analysis shows that the Bloch waves at the Fermi-level propagate through a parallel junction without reflection only at an optimal value of contact length. For quite a long junction, however, the conductance at the Fermi level diminishes due to the perturbation of periodic potential field of close-packed CNTs. Thus, a macroscopic fiber, containing an infinite number of junctions, forms a filter that permits passage of electrons with specific wave vectors, and these wave vectors are determined by the collection of all the junction lengths. We also argue that the energy gap introduced by long junctions can be overcome by small voltage (˜0.04 V) across the whole fiber. Overall, developing long individual all-armchair metallic CNTs serves as a promising way to the manufacture of high-conductivity fibers.

  15. Revealing the molecular structure of single-molecule junctions in different conductance states by fishing-mode tip-enhanced Raman spectroscopy.

    PubMed

    Liu, Zheng; Ding, Song-Yuan; Chen, Zhao-Bin; Wang, Xiang; Tian, Jing-Hua; Anema, Jason R; Zhou, Xiao-Shun; Wu, De-Yin; Mao, Bing-Wei; Xu, Xin; Ren, Bin; Tian, Zhong-Qun

    2011-01-01

    The conductance of single-molecule junctions may be governed by the structure of the molecule in the gap or by the way it bonds with the leads, and the information contained in a Raman spectrum is ideal for examining both. Here we demonstrate that molecule-to-surface bonding may be characterized during electron transport by 'fishing-mode' tip-enhanced Raman spectroscopy (FM-TERS). This technique allows mutually verifiable single-molecule conductance and Raman signals with single-molecule contributions to be acquired simultaneously at room temperature. Density functional theory calculations reveal that the most significant spectral change seen for a gold-4,4'-bipyridine-gold junction results from the deformation of the pyridine ring in contact with the drain electrode at high voltage, and these calculations suggest that a stronger bonding interaction between the molecule and the drain may account for the nonlinear dependence of conductance on bias voltage. FM-TERS will lead to a better understanding of electron-transport processes in molecular junctions.

  16. Kink-mode oscillations of the magnetotail current sheet driven by quasi-continuous reconnection during a steady magnetospheric convection: Geotail and THEMIS conjunction

    NASA Astrophysics Data System (ADS)

    Hasegawa, H.; Shinohara, I.; Nagai, T.; Hoshino, M.; Saito, Y.; Angelopoulos, V.; Teramoto, M.; Higashimori, K.

    2015-12-01

    We present in situ evidence for MHD-scale kink-mode waves propagating earthward in the Earth's magnetotail. The event occurred on 11 October 2014 when the Geotail spacecraft, situated at the GSM position (-26, 9, 0) Re, observed earthward reconnection jets almost continuously for a few hours under stably southward interplanetary magnetic field conditions. The reconnection jets had a speed of ~700 km/s, comparable to the lobe Alfven speed, and concurred with quasi-periodic crossings of the tail current sheet with a period of 2-3 min. Two of the THEMIS spacecraft, located in the pre-midnight sector at X ~ -10 Re, observed no significant flows, and the cross-polar cap potential estimated from SuperDARN remained more than 50 kV and roughly constant, signatures expected for a steady magnetospheric convection (SMC) interval. The Grad-Shafranov reconstruction of the oscillatory current sheet indicates that kink-mode waves propagated roughly earthward, with a wavelength of ~15 Re and amplitude of order 1 Re. The ions observed off the center of the tail current sheet consisted of field-aligned ion beams and cold lobe ions, characteristic of the plasma sheet boundary layer, which led to parallel ion temperature being higher than the perpendicular temperature. We interpret the observed kink-mode waves as being due to the streaming kink instability (SKI) excited in the reconnection jet and in the presence of temperature anisotropy. Since the SKI can generate Alfvénic waves or turbulence, the observed field fluctuations may be an energy source for auroral activities during SMC intervals. Our observations show that the tail plasma sheet can be dynamic even under a globally steady magnetospheric condition.

  17. Efficient continuous-wave and 739 fs mode-locked laser on a novel Nd3+, La3+ co-doped SrF2 disordered crystal

    NASA Astrophysics Data System (ADS)

    Zhang, Feng; Liu, Jingjing; Liu, Jie; Ma, Fengkai; Jiang, Dapeng; Pang, Siyuan; Su, Liangbi; Xu, Jun

    2016-09-01

    A novel Nd3+, La3+ co-doped SrF2 disordered crystal was successfully fabricated and its laser performance was investigated for the first time. We obtained a continuous-wave (CW) laser with maximum average output power of 1.234 W at 1061 nm, with the corresponding slope efficiency as high as 50.6%. In mode-locked operation, a pulse as short as 739 fs was also obtained without any measures compensating for the dispersion, which suggests that Nd3+, La3+:SrF2 disordered crystal is a promising candidate to generate high-energy ultra-short pulse laser at 1 µm.

  18. 1.9 W continuous-wave single transverse mode emission from 1060 nm edge-emitting lasers with vertically extended lasing area

    SciTech Connect

    Miah, M. J. Posilovic, K.; Kalosha, V. P.; Rosales, R.; Bimberg, D.; Kettler, T.; Skoczowsky, D.; Pohl, J.; Weyers, M.

    2014-10-13

    High-brightness edge-emitting semiconductor lasers having a vertically extended waveguide structure emitting in the 1060 nm range are investigated. Ridge waveguide (RW) lasers with 9 μm stripe width and 2.64 mm cavity length yield highest to date single transverse mode output power for RW lasers in the 1060 nm range. The lasers provide 1.9 W single transverse mode optical power under continuous-wave (cw) operation with narrow beam divergences of 9° in lateral and 14° (full width at half maximum) in vertical direction. The beam quality factor M{sup 2} is less than 1.9 up to 1.9 W optical power. A maximum brightness of 72 MWcm{sup −2}sr{sup −1} is obtained. 100 μm wide and 3 mm long unpassivated broad area lasers provide more than 9 W optical power in cw operation.

  19. Electric field variations measured continuously in free air over a conductive thin zone in the tilted Lias-epsilon black shales near Osnabrück, Northwest Germany

    NASA Astrophysics Data System (ADS)

    Gurk, M.; Bosch, F. P.; Tougiannidis, N.

    2013-04-01

    Common studies on the static electric field distribution over a conductivity anomaly use the self-potential method. However, this method is time consuming and requires nonpolarizable electrodes to be placed in the ground. Moreover, the information gained by this method is restricted to the horizontal variations of the electric field. To overcome the limitation in the self-potential technique, we conducted a field experiment using a non conventional technique to assess the static electric field over a conductivity anomaly. We use two metallic potential probes arranged on an insulated boom with a separation of 126 cm. When placed into the electric field of the free air, a surface charge will be induced on each probe trying to equalize with the potential of the surrounding atmosphere. The use of a plasma source at both probes facilitated continuous and quicker measurement of the electric field in the air. The present study shows first experimental measurements with a modified potential probe technique (MPP) along a 600-meter-long transect to demonstrate the general feasibility of this method for studying the static electric field distribution over shallow conductivity anomalies. Field measurements were carried out on a test site on top of the Bramsche Massif near Osnabrück (Northwest Germany) to benefit from a variety of available near surface data over an almost vertical conductivity anomaly. High resolution self-potential data served in a numerical analysis to estimate the expected individual components of the electric field vector. During the experiment we found more anomalies in the vertical and horizontal components of the electric field than self-potential anomalies. These contrasting findings are successfully cross-validated with conventional near surface geophysical methods. Among these methods, we used self-potential, radiomagnetotelluric, electric resistivity tomography and induced polarization data to derive 2D conductivity models of the subsurface in

  20. Numerical simulation of quench protection for a 1.5 T persistent mode MgB2 conduction-cooled MRI magnet

    NASA Astrophysics Data System (ADS)

    Deissler, Robert J.; Baig, Tanvir; Poole, Charles; Amin, Abdullah; Doll, David; Tomsic, Michael; Martens, Michael

    2017-02-01

    The active quench protection of a 1.5 T MgB2 conduction-cooled MRI magnet operating in persistent current mode is considered. An active quench protection system relies on the detection of the resistive voltage developed in the magnet, which is used to trigger the external energizing of quench heaters located on the surfaces of all ten coil bundles. A numerical integration of the heat equation is used to determine the development of the temperature profile and the maximum temperature in the coil at the origin, or ‘hot spot’, of the quench. Both n-value of the superconductor and magnetoresistance of the wire are included in the simulations. An MgB2 wire manufactured by Hyper Tech Research, Inc. was used as the basis to model the wire for the simulations. With the proposed active quench protection system, the maximum temperature was limited to 200 K or less, which is considered low enough to prevent damage to the magnet. By substituting Glidcop for the Monel in the wire sheath or by increasing the thermal conductivity of the insulation, the margin for safe operation was further increased, the maximum temperature decreasing by more than 40 K. The strain on the MgB2 filaments is calculated using ANSYS, verifying that the stress and strain limits in the MgB2 superconductor and epoxy insulation are not exceeded.

  1. A parametric study for the generation of ion Bernstein modes from a discrete spectrum to a continuous one in the inner magnetosphere. II. Particle-in-cell simulations

    NASA Astrophysics Data System (ADS)

    Sun, Jicheng; Gao, Xinliang; Lu, Quanming; Chen, Lunjin; Tao, Xin; Wang, Shui

    2016-02-01

    In this paper, we perform one-dimensional particle-in-cell simulations to investigate the properties of perpendicular magnetosonic waves in a plasma system consisting of three components: cool electrons, cool protons, and tenuous ring distribution protons, where the waves are excited by the tenuous proton ring distribution. Consistent with the linear theory, the spectra of excited magnetosonic waves can change from discrete to continuous due to the overlapping of adjacent unstable wave modes. The increase of the proton to electron mass ratio, the ratio of the light speed to the Alfven speed, or the concentration of protons with a ring distribution tends to result in a continuous spectrum of magnetosonic waves, while the increase of the ring velocity of the tenuous proton ring distribution leads to a broader one, but with a discrete structure. Moreover, the energization of both cool electrons and protons and the scattering of ring distribution protons due to the excited magnetosonic waves are also observed in our simulations, which cannot be predicted by the linear theory. Besides, a thermalized proton ring distribution may lead to the further excitation of several lower discrete harmonics with their frequencies about several proton gyrofrequencies.

  2. Determination of mass of an isolated neutron star using continuous gravitational waves with two frequency modes: an effect of a misalignment angle

    NASA Astrophysics Data System (ADS)

    Eda, Kazunari; Ono, Kenji; Itoh, Yousuke

    2016-05-01

    A rapidly spinning neutron star (NS) would emit a continuous gravitational wave (GW) detectable by the advanced LIGO, advanced Virgo, KAGRA and proposed third generation detectors such as the Einstein Telescope (ET). Such a GW does not propagate freely, but is affected by the Coulomb-type gravitational field of the NS itself. This effect appears as a phase shift in the GW depending on the NS mass. We have shown that mass of an isolated NS can, in principle, be determined if we could detect the continuous GW with two or more frequency modes. Indeed, our Monte Carlo simulations have demonstrated that mass of a NS with its ellipticity 10-6 at 1 kpc is typically measurable with precision of 20% using the ET, if the NS is precessing or has a pinned superfluid core and emits GWs with once and twice the spin frequencies. After briefly explaining our idea and results, this paper concerns with the effect of misalignment angle (“wobble angle” in the case of a precessing NS) on the mass measurement precision.

  3. Heat conduction in conducting polyaniline nanofibers

    NASA Astrophysics Data System (ADS)

    Nath, Chandrani; Kumar, A.; Syu, K.-Z.; Kuo, Y.-K.

    2013-09-01

    Thermal conductivity and specific heat of conducting polyaniline nanofibers are measured to identify the nature of heat carrying modes combined with their inhomogeneous structure. The low temperature thermal conductivity results reveal crystalline nature while the high temperature data confirm the amorphous nature of the material suggesting heterogeneous model for conducting polyaniline. Extended acoustic phonons dominate the low temperature (<100 K) heat conduction, while localized optical phonons hopping, assisted by the extended acoustic modes, account for the high temperature (>100 K) heat conduction.

  4. Continuous tidal streamflow, water level, and specific conductance data for Union Creek and the Little Back, Middle, and Front Rivers, Savannah River Estuary, November 2008 to March 2009

    USGS Publications Warehouse

    Lanier, Timothy H.; Conrads, Paul A.

    2010-01-01

    In the Water Resource Development Act of 1999, the U.S. Congress authorized the deepening of the Savannah Harbor. Additional studies were then identified by the Georgia Ports Authority and other local and regional stakeholders to determine and fully describe the potential environmental effects of deepening the channel. One need that was identified was the validation of a three-dimensional hydrodynamic model developed to evaluate mitigation scenarios for a potential harbor deepening and the effects on the Savannah River estuary. The streamflow in the estuary is very complex due to reversing tidal flows, interconnections of streams and tidal creeks, and the daily flooding and draining of the marshes. The model was calibrated using very limited streamflow data and no continuous streamflow measurements. To better characterize the streamflow dynamics and mass transport of the estuary, two index-velocity sites were instrumented with continuous acoustic velocity, water level, and specific conductance sensors on the Little Back and Middle Rivers for the 5-month period of November 2008 through March 2009. During the same period, a third acoustic velocity meter was installed on the Front River just downstream from U.S. Geological Survey streamgaging station 02198920 (Savannah River at GA 25, at Port Wentworth, Georgia) where water level and specific conductance data were being collected. A fourth index-velocity site was instrumented with continuous acoustic velocity, water level, and specific conductance sensors on Union Creek for a 2-month period starting in November 2008. In addition to monitoring the tidal cycles, streamflow measurements were made at the four index-velocity sites to develop ratings to compute continuous discharge for each site. The maximum flood (incoming) and ebb (outgoing) tides measured on Little Back River were –4,570 and 7,990 cubic feet per second, respectively. On Middle River, the maximum flood and ebb tides measured were –9,630 and 13

  5. Mechanical design and fabrication of the VHF-gun, the Berkeley normal-conducting continuous-wave high-brightness electron source

    NASA Astrophysics Data System (ADS)

    Wells, R. P.; Ghiorso, W.; Staples, J.; Huang, T. M.; Sannibale, F.; Kramasz, T. D.

    2016-02-01

    A high repetition rate, MHz-class, high-brightness electron source is a key element in future high-repetition-rate x-ray free electron laser-based light sources. The VHF-gun, a novel low frequency radio-frequency gun, is the Lawrence Berkeley National Laboratory (LBNL) response to that need. The gun design is based on a normal conducting, single cell cavity resonating at 186 MHz in the VHF band and capable of continuous wave operation while still delivering the high accelerating fields at the cathode required for the high brightness performance. The VHF-gun was fabricated and successfully commissioned in the framework of the Advanced Photo-injector EXperiment, an injector built at LBNL to demonstrate the capability of the gun to deliver the required beam quality. The basis for the selection of the VHF-gun technology, novel design features, and fabrication techniques are described.

  6. Mechanical design and fabrication of the VHF-gun, the Berkeley normal-conducting continuous-wave high-brightness electron source.

    PubMed

    Wells, R P; Ghiorso, W; Staples, J; Huang, T M; Sannibale, F; Kramasz, T D

    2016-02-01

    A high repetition rate, MHz-class, high-brightness electron source is a key element in future high-repetition-rate x-ray free electron laser-based light sources. The VHF-gun, a novel low frequency radio-frequency gun, is the Lawrence Berkeley National Laboratory (LBNL) response to that need. The gun design is based on a normal conducting, single cell cavity resonating at 186 MHz in the VHF band and capable of continuous wave operation while still delivering the high accelerating fields at the cathode required for the high brightness performance. The VHF-gun was fabricated and successfully commissioned in the framework of the Advanced Photo-injector EXperiment, an injector built at LBNL to demonstrate the capability of the gun to deliver the required beam quality. The basis for the selection of the VHF-gun technology, novel design features, and fabrication techniques are described.

  7. Reduction of Common-Mode Conducted Noise Emissions in PWM Inverter-fed AC Motor Drive Systems using Optimized Passive EMI Filter

    NASA Astrophysics Data System (ADS)

    Jettanasen, C.; Ngaopitakkul, A.

    2010-10-01

    Conducted electromagnetic interference (EMI) generated by PWM inverter-fed induction motor drive systems, which are currently widely used in many industrial and/or avionic applications, causes severe parasitic current problems, especially at high frequencies (HF). These restrict power electronic drive's evolution. In order to reduce or minimize these EMI problems, several techniques can be applied. In this paper, insertion of an optimized passive EMI filter is proposed. This filter is optimized by taking into account real impedances of each part of a considered AC motor drive system contrarily to commercial EMI filters designed by considering internal impedance of disturbance source and load, equal to 50Ω. Employing the latter EMI filter would make EMI minimization less effective. The proposed EMI filter optimization is mainly dedicated to minimize common mode (CM) currents due to its most dominant effects in this kind of system. The efficiency of the proposed optimization method using two-port network approach is deduced by comparing the minimized CM current spectra to an applied normative level (ex. DO-160D in aeronautics).

  8. Microstructure correlation in high-strength steels with continuous stiffness mode nanoindentation results. High-resolution vs. low-resolution nanoindentation

    NASA Astrophysics Data System (ADS)

    Hackney, Stephen A.; Bradley, John R.; Wood, Thomas D.; Miskioglu, Ibrahim

    2013-04-01

    This study utilizes instrumented nanoindentation to compare the mechanical response of a transformation-induced plasticity (TRIP) steel to that of a quench and partition steel (QP). The nanoindenter was operated using continuous stiffness mode, and the microstructure under the indent revealed by chemical etching was examined. Examination of the microstructure in the indents by scanning electron microscopy allows a direct correlation with nanoindentation properties. It is found that the hardness measured at an indentation depth of 1.1 μm is, on average, significantly greater in the QP steel than in the TRIP steel. The continuous hardness measurement also allows the microstructure observed at the center of the indent to be correlated with the hardness values when indentation depths are <0.1 μm. This high-resolution hardness measurement allows for a direct comparison of mechanical response for the individual retained austenite phase particles in the TRIP steel with the strengthening microconstituent in the QP steel. With this methodology, the surprising result is that the TRIP retained austenite particles have a higher hardness than the QP hardening microconstituent. It is proposed that the resolution of the apparent disagreement between the hardness measurements obtained at 1.1 μm depth (QP has the higher hardness) and the 0.1-μm depth hardness measurements of the microconstituents containing retained austenite (TRIP has the higher hardness) lies in the volume fraction of the microconstituent as the QP has a two- to threefold higher volume fraction of hardening phase as compared to TRIP.

  9. Scale effect of anaerobic digestion tests in fed-batch and semi-continuous mode for the technical and economic feasibility of a full scale digester.

    PubMed

    Ruffino, Barbara; Fiore, Silvia; Roati, Chiara; Campo, Giuseppe; Novarino, Daniel; Zanetti, Mariachiara

    2015-04-01

    Methane production capacity in mesophilic conditions of waste from two food industry plants was assessed in a semi-pilot (6L, fed-batch) and pilot (300 L, semi-continuous) scale. This was carried out in order to evaluate the convenience of producing heat and electricity in a full scale anaerobic digester. The pilot test was performed in order to obtain more reliable results for the design of the digester. Methane yield, returned from the pilot scale test, was approximately 80% of that from the smaller scale test. This outcome was in line with those from other studies performed in different scales and modes and indicates the success of the pilot scale test. The net electricity produced from the digester accounted for 30-50% of the food industry plants' consumption. The available thermal energy could cover from 10% to 100% of the plant requirements, depending on the energy demand of the processes performed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Safety Management of a Clinical Process Using Failure Mode and Effect Analysis: Continuous Renal Replacement Therapies in Intensive Care Unit Patients.

    PubMed

    Sanchez-Izquierdo-Riera, Jose Angel; Molano-Alvarez, Esteban; Saez-de la Fuente, Ignacio; Maynar-Moliner, Javier; Marín-Mateos, Helena; Chacón-Alves, Silvia

    2016-01-01

    The failure mode and effect analysis (FMEA) may improve the safety of the continuous renal replacement therapies (CRRT) in the intensive care unit. We use this tool in three phases: 1) Retrospective observational study. 2) A process FMEA, with implementation of the improvement measures identified. 3) Cohort study after FMEA. We included 54 patients in the pre-FMEA group and 72 patients in the post-FMEA group. Comparing the risks frequencies per patient in both groups, we got less cases of under 24 hours of filter survival time in the post-FMEA group (31 patients 57.4% vs. 21 patients 29.6%; p < 0.05); less patients suffered circuit coagulation with inability to return the blood to the patient (25 patients [46.3%] vs. 16 patients [22.2%]; p < 0.05); 54 patients (100%) versus 5 (6.94%) did not get phosphorus levels monitoring (p < 0.05); in 14 patients (25.9%) versus 0 (0%), the CRRT prescription did not appear on medical orders. As a measure of improvement, we adopt a dynamic dosage management. After the process FMEA, there were several improvements in the management of intensive care unit patients receiving CRRT, and we consider it a useful tool for improving the safety of critically ill patients.

  11. Assessing acute toxicity of effluent from a textile industry and nearby river waters using sulfur-oxidizing bacteria in continuous mode.

    PubMed

    Gurung, Anup; Hassan, Sedky H A; Oh, Sang-Eun

    2011-10-01

    Bioassays are becoming an important tool for assessing the toxicity of complex mixtures of substances in aquatic environments in which Daphnia magna is routinely used as a test organism. Bioassays outweigh physicochemical analyses and are valuable in the decision-making process pertaining to the final discharge of effluents from wastewater treatment plants as they measure the total effect of the discharge which is ecologically relevant. In this study, the aquatic toxicity of a textile plant effluent and river water downstream from the plant were evaluated with sulfur-oxidizing bacterial biosensors in continuous mode. Collected samples were analysed for different physicochemical parameters and 1,4-dioxane was detected in the effluent. The effluent contained a relatively high chemical oxygen demand of 60 mg L(-1), which exceeded the limit set by the Korean government for industrial effluent discharges. Results showed that both the effluent and river waters were toxic to sulfur-oxidizing bacteria. These results show the importance of incorporating bioassays to detect toxicity in wastewater effluents for the sustainable management of water resources.

  12. Continuous mode of carbon dioxide sequestration by C. sorokiniana and subsequent use of its biomass for hydrogen production by E. cloacae IIT-BT 08.

    PubMed

    Kumar, Kanhaiya; Roy, Shantonu; Das, Debabrata

    2013-10-01

    The present study investigated to find out the suitability of the CO2 sequestered algal biomass of Chlorella sorokiniana as substrate for the hydrogen production by Enterobacter cloacae IIT-BT 08. The maximum biomass productivity in continuous mode of operation in autotrophic condition was enhanced from 0.05 g L(-1) h(-1) in air to 0.11 g L(-1) h(-1) in 5% air-CO2 (v/v) gas mixture at an optimum dilution rate of 0.05 h(-1). Decrease in steady state biomass and productivity was less sensitive at higher dilution and found fitting with the model proposed by Eppley and Dyer (1965). Pretreated algal biomass of 10 g L(-1) with 2% (v/v) HCl-heat was found most suitable for hydrogen production yielding 9±2 mol H2 (kg COD reduced)(-1) and was found fitting with modified Gompertz equation. Further, hydrogen energy recovery in dark fermentation was significantly enhanced compared to earlier report of hydrogen production by biophotolysis of algae. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. A study on large scale cultivation of Microcystis aeruginosa under open raceway pond at semi-continuous mode for biodiesel production.

    PubMed

    Ashokkumar, Veeramuthu; Agila, Elango; Salam, Zainal; Ponraj, Mohanadoss; Din, Mohd Fadhil Md; Ani, Farid Nasir

    2014-11-01

    The study explores on upstream and downstream process in Microcystis aeruginosa for biodiesel production. The alga was isolated from temple tank, acclimatized and successfully mass cultivated in open raceway pond at semi-continuous mode. A two step combined process was designed and harvested 99.3% of biomass, the daily dry biomass productivity was recorded up to 28gm(-2)day(-1). The lipid extraction was optimized and achieved 21.3%; physicochemical properties were characterized and found 11.7% of FFA, iodine value 72% and 99.2% of ester content. The lipid was transesterified by a two step simultaneous process and produced 90.1% of biodiesel; the calorific value of the biodiesel was 38.8MJ/kg. Further, the physicochemical properties of biodiesel was characterized and found to be within the limits of American ASTM D6751. Based on the areal and volumetric biomass productivity estimation, M. aeruginosa can yield 84.1 tons of dry biomass ha(-1)year(-1).

  14. Comparative Analyses of Multi-Pulse Phase Controlled Rectifiers in Continuous Conduction Mode with a Two-Pole LC Output Filter for Surface Ship DC Applications

    DTIC Science & Technology

    2013-03-01

    these issues and determining the means of assuring compatibility with a Navy all- electric ship is the focus of this thesis. By using a Simulink...the requirements for the degree of MASTER OF SCIENCE IN ELECTRICAL ENGINEERING from the NAVAL POSTGRADUATE SCHOOL March 2013...Department of Electrical and Computer Engineering iv THIS PAGE INTENTIONALLY LEFT BLANK v ABSTRACT The Navy of tomorrow will require a robust and

  15. Groundwater discharge to wetlands driven by storm and flood events: Quantification using continuous Radon-222 and electrical conductivity measurements and dynamic mass-balance modelling

    NASA Astrophysics Data System (ADS)

    Gilfedder, B. S.; Frei, S.; Hofmann, H.; Cartwright, I.

    2015-09-01

    The dynamic response of groundwater discharge to external influences such as rainfall is an often neglected part of water and solute balances in wetlands. Here we develop a new field platform for long-term continuous 222Rn and electrical conductivity (EC) measurements at Sale Wetland, Australia to study the response of groundwater discharge to storm and flood events. The field measurements, combined with dynamic mass-balance modelling, demonstrate that the groundwater flux can increase from 3 to ∼20 mm d-1 following storms and up to 5 mm d-1 on the receding limb of floods. The groundwater pulses are likely produced by activation of local groundwater flow paths by water ponding on the surrounding flood plains. While 222Rn is a sensitive tracer for quantifying transient groundwater discharge, the mass-balance used to estimate fluxes is sensitive to parameterisation of gas exchange (k) with the atmosphere. Comparison of six equations for calculating k showed that, based on parameterisation of k alone, the groundwater flux estimate could vary by 58%. This work shows that neglecting transient processes will lead to errors in water and solute flux estimates based on infrequent point measurements. This could be particularly important for surface waters connected to contaminated or saline groundwater systems.

  16. Capillary electrochromatography using continuous-bed columns of sol-gel bonded silica particles with mixed-mode octadecyl and propylsulfonic acid functional groups.

    PubMed

    Tang, Q; Lee, M L

    2000-07-28

    Continuous-bed columns containing sol-gel bonded 3 microm silica particles with mixed-mode octadecyl and propylsulfonic acid functional groups (ODS/SCX) were prepared by first packing the ODS/SCX particles into a fused-silica capillary, then filling the packed capillary with a siliceous sol-gel, curing the sol-gel, and finally drying the column with supercritical carbon dioxide. The performance of the sol-gel bonded ODS/SCX columns was evaluated for capillary electrochromatography using acetonitrile aqueous mobile phase containing phosphate buffer. The columns were mechanically strong and permeable. Both EOF velocity and current increased linearly with elevation of the applied electric field strength. The EOF velocity was high at low pH and nearly constant over a range of pH 2-9. Higher buffer concentration resulted in higher current and lower EOF velocity. The acetonitrile content had no significant effect on the EOF. Without thermosetting the column, no bubble formation was noticed with currents up to 2.5 microA. The minimum plate height of a 25/34 cm x 75 microm I.D. sol-gel bonded 3 microm ODS/SCX column was 5.7 microm (1.75 x 10(5) plates per meter) at an optimum EOF velocity of 0.92 mm s(-1). Mixtures of test aromatic compounds and aromatic hydrocarbon homologues gave symmetrical peaks when using a low pH mobile phase. The retention and elution order of aromatic compounds represented a typical reversed-phase separation mechanism similar to conventional ODS columns. The run-to-run and column-to-column retention factor reproducibility was better than 2.5% and 8.0% RSD, respectively.

  17. Measurement of the absorption coefficient of CO2 laser windows with hysteresis in the power-tuning curve of a single-mode continuous-wave CO2 laser.

    PubMed

    Nagarkar, M M; Gupta, P K

    1997-12-20

    We report a new method for the measurement of the absorption coefficient of CO(2) laser windows. The method exploits the hysteresis in the power-tuning curve of a single-mode continuous-wave CO(2) laser and allows measurements of absorption coefficients of the order of approximately 10(-3) cm(-1) in CO(2) laser windows a few millimeters thick.

  18. A 1550-nm linearly tunable continuous wave single-mode external cavity diode laser based on a single-cavity all-dielectric thin-film Fabry—Pérot filter

    NASA Astrophysics Data System (ADS)

    Xiao, Xiao; Lu, Yuan-Fu; Yu, Feng-Qi; Jin, Lei

    2013-07-01

    A 1550-nm linearly tunable continuous wave (CW) single-mode external cavity diode laser (ECDL) based on a single-cavity all-dielectric thin-film Fabry—Pérot filter (s-AFPF) is proposed and realized in this paper. Its internal optical components as well as their operation mechanisms are introduced first, and then its longitudinal mode output characteristic is theoretically analyzed. Afterwards, we set up the experimental platform for the output characteristic measurement of this tunable ECDL; under different experimental conditions, we execute accurate and real-time measurements for the output central wavelength, output optical power, output longitudinal mode distribution, and the line-width of the tunable ECDL in its tuning process. By summing up the optimal experimental condition from the measured data, we obtain the optimal tunable ECDL relevant parameters: the tunable ECDL has a linear mode-hop-free wavelength tuning region of 1547.203 nm-1552.426 nm, a stable output optical power in the range of 40 μW-50 μW, and a stable output longitudinal mode distribution of a single longitudinal mode with a line-width in the range of 100 MHz-150 MHz. This tunable ECDL can be used in environmental gas monitoring, atomic and molecular laser spectroscopy research, precise measurements, and so on.

  19. A Review and Empirical Comparison of Three Treatments for Adolescent Males with Conduct and Personality Disorder: Mode Deactivation Therapy, Cognitive Behavior Therapy and Social Skills Training

    ERIC Educational Resources Information Center

    Apsche, Jack A.; Bass, Christopher K.; Siv, Alexander M.

    2005-01-01

    This treatment research study extended the results of Apsche, Bass, Jennings, Murphy, Hunter, and Siv (2005), from behavioral data to standard measures of psychological distress. In Apsche, et. al. (2005) results suggest that Mode Deactivation Therapy (MDT) was more effective than Cognitive Behavior Therapy (CBT) and Social Skills Therapy (SST) in…

  20. 5.5 W continuous-wave TEM00-mode Nd:YAG solar laser by a light-guide/2V-shaped pump cavity

    NASA Astrophysics Data System (ADS)

    Almeida, J.; Liang, D.; Vistas, C. R.; Bouadjemine, R.; Guillot, E.

    2015-12-01

    A significant progress in TEM00-mode solar laser power and efficiency with heliostat-parabolic mirror system is reported here. A double-stage light-guide/2V-shaped pump cavity is used to efficiently couple and redistribute the concentrated pump light from a 2-m-diameter parabolic mirror to a 4-mm-diameter, 30-mm-length, 1.1 at.% Nd:YAG single-crystal rod. The light guide with large rectangular cross section enables a stable uniform pumping profile along the laser rod, resulting also in an enhanced tracking error compensation capacity. 5.5 W cw TEM00-mode solar laser power was measured at the output of a thermally near unstable asymmetric resonator. 150 and 157 % improvement in TEM00-mode solar laser collection efficiency and slope efficiency were obtained, respectively.

  1. Relationships between antimicrobial effect and area under the concentration-time curve as a basis for comparison of modes of antibiotic administration: meropenem bolus injections versus continuous infusions.

    PubMed Central

    Firsov, A A; Mattie, H

    1997-01-01

    In comparative studies of different modes of administration (MAs) simulated in in vitro dynamic models, only one dose of antibiotic is usually mimicked. Such an experimental design can provide a prediction of the antimicrobial effect (AME) of a given combination of drug, clinical isolate, and infection site, but may be inappropriate for accurate comparison of MAs. An alternative design providing comparison of different MAs with various antibiotic doses in a wide range and with evaluation of the respective relationships between AME and the AUC was proposed and examined. Two series of meropenem pharmacokinetic profiles, i.e., monoexponentially decreasing concentrations (bolus doses) and constant concentrations (6-h continuous infusion), were in vitro simulated. The simulated initial concentrations (Co[from 0.62 to 48 micrograms/ml]) and steady-state concentrations (Css[from 0.016 to 8 micrograms/ml]) were chosen to provide similar AUC for 0 to 6 h (AUC0-6) ranges for both MAs (from 0.070 to 50.0 micrograms.h/ml and from 0.09 to 48.0 micrograms.h/ml, respectively). The AME of meropenem on Staphylococcus aureus ATCC 25923 (MIC, 0.06 micrograms/ml) was determined at each time (t) point as a difference (E) between the logarithms of viable counts (N) in the control cultures without antibiotic (NC) and in cultures exposed to antibiotics (NA). Time courses of E observed at different Co of Css levels were compared in terms of the areas under the E-t curves (ABBCt). The finite values of the ABBCt observed by the end of the 6 -h observation period, which are equivalent to the area between bacterial count-time curves observed in the absence and presence of antibiotic (ABBC), were plotted versus the respective AUCs produced by each of the MAs. The ABBC versus AUC curves had a similar pattern: a plateau achieved at high AUCs followed by a steep rise in ABBC at relatively low AUCs was inherent in both of the MAs. The superiority of bolus dosing over the infusions could be

  2. The physics of transverse mode instability-induced nonlinear phase distortions in large area optical fiber amplifiers and their mitigation with applications in scaling of pulsed and continuous wave high-energy lasers

    DTIC Science & Technology

    2016-12-13

    their mitigation with applications in scaling of pulsed and continuous- wave high- energy lasers Balaji Srinivasan INDIAN INSTITUTE OF TECHNOLOGY...high- energy lasers 5a.  CONTRACT NUMBER 5b.  GRANT NUMBER FA2386-15-1-5044 5c.  PROGRAM ELEMENT NUMBER 61102F 6. AUTHOR(S) Balaji Srinivasan 5d...use of vortex beams to mitigate thermal mode instability in high energy fiber amplifiers. The investigation is carried out through (1) the

  3. Study of semi-transparent conductive layers for the realization of high quantum efficiency transmission mode CsI photocathodes for vacuum photodetectors

    NASA Astrophysics Data System (ADS)

    Barbato, F. C. T.; Valentini, A.; Casamassima, G.; Campajola, L.; Di Capua, F.

    2017-07-01

    We worked on the R&D of an innovative photodetector, the Vacuum Silicon Photomultiplier Tube (VSiPMT). The VSiPMT is composed by a photocathode and a solid state amplification stage. A semi-transparent conductive layer is necessary to supply voltage and to obtain a highly efficient CsI photocathode. Since the literature is poor on this topic we performed a systematic and detailed study of a set of semi-transparent conductive layers, made by different material and thickness. A CsI photocathode was evaporated on each sample. The impact of the semi-transparent conductive layer on the quantum efficiency of the photocathode is discussed.

  4. Optimization of passively mode-locked quasi-continuously diode-pumped Nd:GdVO4 laser in bounce geometry

    NASA Astrophysics Data System (ADS)

    Frank, Milan; Jelínek, Michal; Kubeček, Václav

    2015-01-01

    In this paper the operation of pulsed diode-pumped Nd:GdVO4 laser oscillator in bounce geometry passively modelocked using semiconductor saturable absorber mirror (SAM), generating microjoule level picosecond pulses at wavelength of 1063 nm, is reported. Optimization of the output coupling for generation either Q-switched mode locked pulse trains or cavity dumped single pulses with maximum energy was performed, which resulted in extraction of single pulses as short as 10 ps and energy of 20 uJ. In comparison with the previous results obtained with this Nd:GdVO4 oscillator and saturable absorber in transmission mode, the achieved pulse duration is five times shorter. Using different absorbers and parameters of single pulse extraction enables generation of the pulses with duration up to 100 ps with the energy in the range from 10 to 20 μJ.

  5. Continuous-wave TEM00-mode 26.5-W-output virtual-point-source diode-array-pumped Nd:YAG laser

    NASA Astrophysics Data System (ADS)

    Uehara, N.; Nakahara, K.; Ueda, K.

    1995-08-01

    We describe a novel side-pumping configuration of the virtual-point-source diode-array-pumped Nd:YAG laser with 32 cw 10-W laser diodes. A new concept of the virtual point source and an image-relay system are proposed for the generation of a Gaussian-like pumping profile with an optically thin gain medium. A cw linearly polarized TEM00 -mode, 26.5-W output was obtained at a diode pump power of 171 W. The M2 values at the x and y axes were measured to be M2x=1.03 and M2y=1.20 , respectively.

  6. Measurement of absolute frequency of continuous-wave terahertz radiation in real time using a free-running, dual-wavelength mode-locked, erbium-doped fibre laser

    PubMed Central

    Hu, Guoqing; Mizuguchi, Tatsuya; Zhao, Xin; Minamikawa, Takeo; Mizuno, Takahiko; Yang, Yuli; Li, Cui; Bai, Ming; Zheng, Zheng; Yasui, Takeshi

    2017-01-01

    A single, free-running, dual-wavelength mode-locked, erbium-doped fibre laser was exploited to measure the absolute frequency of continuous-wave terahertz (CW-THz) radiation in real time using dual THz combs of photo-carriers (dual PC-THz combs). Two independent mode-locked laser beams with different wavelengths and different repetition frequencies were generated from this laser and were used to generate dual PC-THz combs having different frequency spacings in photoconductive antennae. Based on the dual PC-THz combs, the absolute frequency of CW-THz radiation was determined with a relative precision of 1.2 × 10−9 and a relative accuracy of 1.4 × 10−9 at a sampling rate of 100 Hz. Real-time determination of the absolute frequency of CW-THz radiation varying over a few tens of GHz was also demonstrated. Use of a single dual-wavelength mode-locked fibre laser, in place of dual mode-locked lasers, greatly reduced the size, complexity, and cost of the measurement system while maintaining the real-time capability and high measurement precision. PMID:28186148

  7. Measurement of absolute frequency of continuous-wave terahertz radiation in real time using a free-running, dual-wavelength mode-locked, erbium-doped fibre laser

    NASA Astrophysics Data System (ADS)

    Hu, Guoqing; Mizuguchi, Tatsuya; Zhao, Xin; Minamikawa, Takeo; Mizuno, Takahiko; Yang, Yuli; Li, Cui; Bai, Ming; Zheng, Zheng; Yasui, Takeshi

    2017-02-01

    A single, free-running, dual-wavelength mode-locked, erbium-doped fibre laser was exploited to measure the absolute frequency of continuous-wave terahertz (CW-THz) radiation in real time using dual THz combs of photo-carriers (dual PC-THz combs). Two independent mode-locked laser beams with different wavelengths and different repetition frequencies were generated from this laser and were used to generate dual PC-THz combs having different frequency spacings in photoconductive antennae. Based on the dual PC-THz combs, the absolute frequency of CW-THz radiation was determined with a relative precision of 1.2 × 10-9 and a relative accuracy of 1.4 × 10-9 at a sampling rate of 100 Hz. Real-time determination of the absolute frequency of CW-THz radiation varying over a few tens of GHz was also demonstrated. Use of a single dual-wavelength mode-locked fibre laser, in place of dual mode-locked lasers, greatly reduced the size, complexity, and cost of the measurement system while maintaining the real-time capability and high measurement precision.

  8. 16 MHz wavelength-swept and wavelength-stepped laser architectures based on stretched-pulse active mode locking with a single continuously chirped fiber Bragg grating

    PubMed Central

    Khazaeinezhad, Reza; Siddiqui, Meena; Vakoc, Benjamin J.

    2017-01-01

    We demonstrate a novel high-speed and broadband laser architecture based on stretched pulse active mode locking that provides a wavelength-swept and wavelength-stepped output. The laser utilizes a single intracavity 8.3 meter chirped fiber Bragg grating to generate positive and negative dispersion, and can be operated with or without an intracavity fixed Fabry–Perot etalon to generate wavelength-swept and wavelength-stepped (frequency comb) outputs, respectively. Using a four-path delay line at the output, we achieved 16.3MHz repetition rates and a 62 nm lasing bandwidth centered at 1550 nm. Single-sided double-pass coherence lengths of 1.25 mm for the wavelength-swept configuration and more than 30 mm for the wavelength-stepped configuration were obtained. Relative intensity noise was measured to be better than −140 dB/Hz. The stretched-pulse mode-locked architecture utilizing long chirped fiber Bragg gratings offers a simple and compact design for a broadband wavelength-tuned output at unprecedented speeds, and can address the need for fast sources in applications such as optical ranging, imaging, and sensing. PMID:28504745

  9. Batch vs continuous-feeding operational mode for the removal of pesticides from agricultural run-off by microalgae systems: A laboratory scale study.

    PubMed

    Matamoros, Víctor; Rodríguez, Yolanda

    2016-05-15

    Microalgae-based water treatment technologies have been used in recent years to treat different water effluents, but their effectiveness for removing pesticides from agricultural run-off has not yet been addressed. This paper assesses the effect of microalgae in pesticide removal, as well as the influence of different operation strategies (continuous vs batch feeding). The following pesticides were studied: mecoprop, atrazine, simazine, diazinone, alachlor, chlorfenvinphos, lindane, malathion, pentachlorobenzene, chlorpyrifos, endosulfan and clofibric acid (tracer). 2L batch reactors and 5L continuous reactors were spiked to 10 μg L(-1) of each pesticide. Additionally, three different hydraulic retention times (HRTs) were assessed (2, 4 and 8 days) in the continuous feeding reactors. The batch-feeding experiments demonstrated that the presence of microalgae increased the efficiency of lindane, alachlor and chlorpyrifos by 50%. The continuous feeding reactors had higher removal efficiencies than the batch reactors for pentachlorobenzene, chlorpyrifos and lindane. Whilst longer HRTs increased the technology's effectiveness, a low HRT of 2 days was capable of removing malathion, pentachlorobenzene, chlorpyrifos, and endosulfan by up to 70%. This study suggests that microalgae-based treatment technologies can be an effective alternative for removing pesticides from agricultural run-off. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. CONTINUOUS-MODE PHOTOCATALYTIC DEGRADATION OF CHLORINATED PHENOLS AND PESTICIDES IN WATER USING A BENCH-SCALE TIO2 ROTATING DISK REACTOR

    EPA Science Inventory

    Photocatalytic degradation of phenol, chlorinated phenols, and lindane was evaluated in a continuous flow TiOz rotating disk photocatalytic reactor (RDPR). The RDPR operated at a hydraulic residence time of 0.25 day and at a disk angular velocity of 12 rpm. At low molar feed conc...

  11. CONTINUOUS-MODE PHOTOCATALYTIC DEGRADATION OF CHLORINATED PHENOLS AND PESTICIDES IN WATER USING A BENCH-SCALE TIO2 ROTATING DISK REACTOR

    EPA Science Inventory

    Photocatalytic degradation of phenol, chlorinated phenols, and lindane was evaluated in a continuous flow TiOz rotating disk photocatalytic reactor (RDPR). The RDPR operated at a hydraulic residence time of 0.25 day and at a disk angular velocity of 12 rpm. At low molar feed conc...

  12. Survival of Listeria monocytogenes, E.coli 0157:H7 and Salmonella spp. on catfish fillets exposed to microwave heating in a continuous mode

    USDA-ARS?s Scientific Manuscript database

    Microwave (MW) heating using continuous power output with feedback control and a modified ingredient formulation, may provide better and consistent cooking of foods. Currently, household units with build-in inverter power supply units are available. These new generation microwave ovens provide con...

  13. Why do the numbers of laboratory animal procedures conducted continue to rise? An analysis of the Home Office Statistics of Scientific Procedures on Living Animals: Great Britain 2005.

    PubMed

    Hudson, Michelle

    2007-03-01

    The publication of the Statistics of Scientific Procedures on Living Animals: Great Britain 2005 once again provides evidence that the levels of animal experimentation in Great Britain are rising, the underlying reason for this being the continued and increasing reliance on genetically modified animals as model systems. There has been a gradual increase in fundamental research, as applied toxicological studies have declined. Of particular concern is the impact that the forthcoming REACH legislation will have and the apparent lack of urgency in facing up to this challenge. The major issues arising from the Statistics are discussed, including the increases in rabbit and primate procedures. The potential of newly validated and emerging techniques to counteract these worrying trends are also considered.

  14. Improved continuity of reduced graphene oxide on polyester fabric by use of polypyrrole to achieve a highly electro-conductive and flexible substrate

    NASA Astrophysics Data System (ADS)

    Berendjchi, Amirhosein; Khajavi, Ramin; Yousefi, Ali Akbar; Yazdanshenas, Mohammad Esmail

    2016-02-01

    A flexible and highly conductive fabric can be applied for wearable electronics and as a pliable counter electrode for photovoltaics. Methods such as surface coating of fabrics with conductive polymers and materials have been developed, but the roughness of fabric is a challenge because it creates discontinuity in the coated layer. The present study first coated polyethylene terephthalate (PET) fabric with reduced graphene oxide sheets; RGO and then filled the gaps with polypyrrole (PPy). The samples were first dipped in graphene oxide (GO) and then reduced to RGO. They were next coated with PPy by in situ polymerization. The results showed that the presence of oxidative agent during synthesis of PPy oxidized the RGO to some extent on the previously RGO-coated samples. PPy was more uniform on samples pre-coated with RGO in comparison those coated with raw PET. The RGO-PPy coated samples exhibited 53% and 263% lower surface resistivity values than samples coated only with PPy and RGO, respectively. There was no significant difference between the tenacity of samples but the bending rigidity of samples increased. The RGO-PPy coated fabric displayed properties, such as excellent UV blocking (UPF = 73), antibacterial activity, improved electrochemical behavior and thermal stability which make it a multifunctional fabric.

  15. The Tamiflu saga continues: will our conduct change after the publication of the latest systematic review on benefits and harms of oseltamivir?

    PubMed

    Bachelet, Vivienne C

    2014-05-20

    In 2013, we wrote about the harm, waste and deception stemming from conducts adopted by the pharmaceutical industry, by concealing raw data and Clinical Study Reports (CSRs) from the regulator’s view when requesting the marketing patent. We described the case of Tamiflu (Roche), a drug that has been widely used in our population and profusely prescribed by physicians. Health authorities, entailing a great cost for the countries in the region, have also purchased it. In this editorial, we will show how the idea of using antivirals for prophylaxis and treatment of influenza took hold, starting from the first enthusiastic recommendations up to the systematic review published last month in the BMJ.

  16. Capacitively coupled contactless conductivity detection as an alternative detection mode in CE for the analysis of kanamycin sulphate and its related substances.

    PubMed

    El-Attug, Mohamed N; Adams, Erwin; Hoogmartens, Jos; Van Schepdael, Ann

    2011-09-01

    A method was developed to determine simultaneously kanamycin, its related substances and sulphate in kanamycin sulphate using capacitively coupled contactless conductivity detection. Kanamycin is an aminoglycoside antibiotic that lacks a strong UV-absorbing chromophore. Due to its physicochemical properties, CE in combination with capacitively coupled contactless conductivity detection was chosen. The separation method uses a BGE composed of 40 mM 2-(N-morpholino)ethanesulphonic acid monohydrate and 40 mM L-histidine, pH 6.35. A 0.6 mM N-cetyltrimethyl ammonium bromide (CTAB) solution was added as electroosmotic flow modifier in a concentration below the critical micellar concentration (CMC). Ammonium acetate 50 mg/L was used as internal standard. In total, 30 kV was applied in reverse polarity on a fused-silica capillary (65/41 cm; 75 μm id). The optimized separation was obtained in less than 6 min with good linearity (R(2)=0.9999) for kanamycin. It shows a good precision expressed as RSD on the relative peak areas equal to 0.3 and 1.1% for intra-day and inter-day precision, respectively. The LOD and LOQ are 0.7 and 2.3 mg/L, respectively. Similarly, for sulphate, a good linearity (R(2)=0.9996) and precision (RSD 0.4 and 0.6% for intra-day and inter-day, respectively) were obtained.

  17. Response to 'Comment on 'Continuum modes in rotating plasmas: General equations and continuous spectra for large aspect ratio tokamaks' '[Phys. Plasmas 19, 064701 (2012)

    SciTech Connect

    Lakhin, V. P.; Ilgisonis, V. I.

    2012-06-15

    The equations for the continuous spectra derived in our paper [V. P. Lakhin and V. I. Ilgisonis, Phys. Plasmas 18, 092103 (2011)] can be reduced to the matrix form used by Goedbloed et al.[Phys. Plasmas 11, 28 (2004)]. It is shown that the assumptions made in our paper provide the elliptic flow regime and guarantee the existence of plasma equilibrium with nested magnetic surfaces of circular cross-section. The new results on magnetohydrodynamic instabilities of such tokamak equilibria obtained in our paper but absent in the paper by Goedbloed et al. are emphasized.

  18. Avalanche mode of high-voltage overloaded p{sup +}–i–n{sup +} diode switching to the conductive state by pulsed illumination

    SciTech Connect

    Kyuregyan, A. S.

    2015-07-15

    A simple analytical theory of the picosecond switching of high-voltage overloaded p{sup +}–i–n{sup +} photodiodes to the conductive state by pulsed illumination is presented. The relations between the parameters of structure, light pulse, external circuit, and main process characteristics, i.e., the amplitude of the active load current pulse, delay time, and switching duration, are derived and confirmed by numerical simulation. It is shown that the picosecond light pulse energy required for efficient switching can be decreased by 6–7 orders of magnitude due to the intense avalanche multiplication of electrons and holes. This offers the possibility of using pulsed semiconductor lasers as a control element of optron pairs.

  19. Comment on 'Continuum modes in rotating plasmas: General equations and continuous spectra for large aspect ratio tokamaks'[Phys. Plasmas 18, 092103 (2011)

    SciTech Connect

    Goedbloed, J. P.

    2012-06-15

    It is shown that some of the main results of the recent paper by Lakhin and Ilgisonis [Phys. Plasmas 18, 092103 (2011)], viz. the derivation of the equations for the continuous spectra of poloidally and toroidally rotating plasmas and their special solution for large aspect ratio tokamaks with large parallel flows were obtained before by Goedbloed, Belieen, van der Holst, and Keppens [Phys. Plasmas 11, 28 (2004)]. A further rearrangement of the system of equations for the coupled Alfven and slow continuous spectra clearly exhibits: (a) coupling through a single tangential derivative, which is a generalization of the geodesic curvature; (b) the 'transonic' transitions of the equilibrium, which need to be carefully examined in order to avoid entering hyperbolic flow regimes where the stability formalism breaks down. A critical discussion is devoted to the implications of this failure, which is generally missed in the tokamak literature, possibly as a result of the wide-spread use of the sonic Mach number of gas dynamics, which is an irrelevant and misleading parameter in 'transonic' magnetohydrodynamics. Once this obstacle in understanding is removed, further application of the theory of trans-slow Alfven continuum instabilities to both tokamaks, with possible implications for the L-H transition, and astrophysical objects like 'fat' accretion disks, with a possible new route to magnetohydrodynamic turbulence, becomes feasible.

  20. Survival of Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella spp. on catfish fillets exposed to microwave heating in a continuous mode.

    PubMed

    Sheen, Shiowshuh; Huang, Lihan; Sommers, Christopher

    2012-08-01

    Microwave (MW) heating using continuous power output with feedback control and a modified ingredient formulation may provide better and consistent cooking of foods. Currently, household units with build-in inverter power supply units are available. These new generation MW ovens provide continuous, adjustable output and cooking, in contrast to the traditional rectifier-based ovens that rely on the on-off mechanism for control. This study attempted to apply a feedback power control (termed as modified or "smart" MW oven) and phosphate treatment to further improve heating uniformity and enhance food quality and safety. Listeria monocytogenes (Lm, 4-strain cocktail), Escherichia coli O157:H7 (Ec, 5-strain cocktail), and Salmonella spp. (Sal, 6-strain cocktail), surface inoculated onto catfish fillets (75 × 100 × 15 mm; weight 110 g), were heated using the modified MW oven to study the inactivation of the pathogens. The sensitivity of these 3 bacteria to MW heating was in the order of Ec (most), Lm, and Sal (least). Greater than 4 to 5 log CFU reductions of Ec, Lm, or Sal counts on catfish fillet surfaces were inactivated within 2 min of 1250 W MW heating, where the fillet surface temperature increased from 10 to 20 °C to 80 to 90 °C. MW heating caused degradation of catfish fillet texture, which was noticeable as early as 10 to 15 s after the heating started, as evidenced by bumping sounds. Bumping can be significantly reduced by soaking fillets in phosphate solution. However, the results may need verification if applied in different MW ovens and/or with foods positioned away the geometric oven center. This study successfully demonstrated the feasibility of applying MW energy to eliminate foodborne pathogens on fish fillets. The results demonstrated in this report with the "smart" microwave oven design may enhance microwaveable food safety and quality, and therefore promote the microwaveable food business. © 2012 Institute of Food Technologists®

  1. Room temperature plasmonic lasing in a continuous wave operation mode from an InGaN/GaN single nanorod with a low threshold

    PubMed Central

    Hou, Y.; Renwick, P.; Liu, B.; Bai, J.; Wang, T.

    2014-01-01

    It is crucial to fabricate nano photonic devices such as nanolasers in order to meet the requirements for the integration of photonic and electronic circuits on the nanometre scale. The great difficulty is to break down a bottleneck as a result of the diffraction limit of light. Nanolasers on a subwavelength scale could potentially be fabricated based on the principle of surface plasmon amplification by stimulated emission of radiation (SPASER). However, a number of technological challenges will have to be overcome in order to achieve a SPASER with a low threshold, allowing for a continuous wave (cw) operation at room temperature. We report a nano-SPASER with a record low threshold at room temperature, optically pumped by using a cw diode laser. Our nano-SPASER consists of a single InGaN/GaN nanorod on a thin SiO2 spacer layer on a silver film. The nanorod containing InGaN/GaN multi-quantum-wells is fabricated by means of a cost-effective post-growth fabrication approach. The geometry of the nanorod/dielectric spacer/plasmonic metal composite allows us to have accurate control of the surface plasmon coupling, offering an opportunity to determine the optimal thickness of the dielectric spacer. This approach will open up a route for further fabrication of electrically injected plasmonic lasers. PMID:24852881

  2. Investigating MALDI MSI parameters (Part 1) - A systematic survey of the effects of repetition rates up to 20kHz in continuous raster mode.

    PubMed

    Steven, Rory T; Dexter, Alex; Bunch, Josephine

    2016-07-15

    Recent developments in laser performance, combined with the desire for increases in detected ion intensity and throughput, have led to the adoption of high repetition-rate diode-pumped solid-state (DPSS) lasers in matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI). Previous studies have demonstrated a more complex relationship between detected ion intensity, stage raster speed and laser pulse repetition rate than the simple linear relationship between number of pulses and detected ion intensity that might be expected. Here we report, for the first time, the interrelated influence of varying laser energy, repetition rate and stage raster speed on detected ion intensity. Thin films of PC 34:1 lipid standard and murine brain tissue with CHCA are analysed by continuous stage raster MALDI MSI. Contrary to previous reports, the optimum laser repetition rate is found to be dependent on both laser energy and stage raster speed and is found to be as high as 20kHz under some conditions. The effects of different repetition rates and raster speeds are also found to vary for different ion species within MALDI MSI of tissue and so may be significant when either targeting specific molecules or seeking to minimize bias. A clear dependence on time between laser pulses is also observed indicating the underlying mechanisms may be related to on-plate hysteresis-exhibiting processes such as matrix chemical modification. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Effect of various colors of light-emitting diodes (LEDs) on the biomass composition of Arthrospira platensis cultivated in semi-continuous mode.

    PubMed

    Markou, Giorgos

    2014-03-01

    In the present study, semi-continuous cultivation of Arthrospira platensis using various colors of light-emitting diodes (LEDs) as artificial lighting was performed in order to study their effects on the biomass composition of A. platensis. The lowest biomass productivity was obtained with blue LED (4.68 mg l(-1) day(-1)), while the highest was obtained with pink and red LEDs (30.89 and 30.69 mg l(-1) day(-1), respectively). All biomass compound contents were affected by the different colors studied, except that of total carotenoids. The lowest phycocyanin content was observed in pink LED (8.2%) while the maximum in blue LED (17.6 ± 2.4%). Chlorophyll content was lowest in red LED (1.04%) and highest in blue LED (1.42%). The highest protein content was obtained with white and green LEDs (50.1 and 49.8%, respectively), while the lowest was obtained with blue LED (42.1%). Carbohydrate content was contrarily affected as that of proteins. The highest carbohydrate content was obtained in blue LED (11.3%) and the lowest under white and pink LEDs (8.8 and 8.8%, respectively). Lipid content seems to follow the same trend as that of carbohydrates; the highest lipid content was obtained in blue LED (6.0%), and the lowest was obtained under pink LED (3.8%).

  4. Dual-Mode Combustion

    NASA Technical Reports Server (NTRS)

    Goyne, Christopher P.; McDaniel, James C.

    2002-01-01

    The Department of Mechanical and Aerospace Engineering at the University of Virginia has conducted an investigation of the mixing and combustion processes in a hydrogen fueled dual-mode scramjet combustor. The experiment essentially consisted of the "direct connect" continuous operation of a Mach 2 rectangular combustor with a single unswept ramp fuel injector. The stagnation enthalpy of the test flow simulated a flight Mach number of 5. Measurements were obtained using conventional wall instrumentation and laser based diagnostics. These diagnostics included, pressure and wall temperature measurements, Fuel Plume Imaging (FPI) and Particle Image Velocimetry (PIV). A schematic of the combustor configuration and a summary of the measurements obtained are presented. The experimental work at UVa was parallel by Computational Fluid Dynamics (CFD) work at NASA Langley. The numerical and experiment results are compared in this document.

  5. Continued improvement in reduced-mode (REM) diodes enable 272 W from 105 μm 0.15 NA beam

    NASA Astrophysics Data System (ADS)

    Kanskar, M.; Bao, L.; Chen, Z.; Dawson, D.; DeVito, M.; Dong, W.; Grimshaw, M.; Guan, X.; Hemenway, M.; Martinsen, R.; Urbanek, W.; Zhang, S.

    2017-02-01

    High-power, high-brightness diode lasers from 8xx nm to 9xx nm have been pursued in many applications including fiber laser pumping, materials processing, solid-state laser pumping, and consumer electronics manufacturing. In particular, 915 nm - 976 nm diodes are of interest as diode pumps for the kilowatt CW fiber lasers. Thus, there have been many technical efforts on driving the diode lasers to have both high power and high brightness to achieve high-performance and reduced manufacturing costs. This paper presents our continued progress in the development of high brightness fiber-coupled product platform, elementTM. In the past decade, the amount of power coupled into a single 105 μm and 0.15 NA fiber has increased by over a factor of ten through improved diode laser brilliance and the development of techniques for efficiently coupling multiple emitters into a single fiber. In this paper, we demonstrate the further brightness improvement and power-scaling enabled by both the rise in chip brightness/power and the increase in number of chips coupled into a given numerical aperture. We report a new x-REM design with brightness as high as 4.3 W/mm-mrad at a BPP of 3 mm-mrad. We also report the record 272W from a 2×9 elementTM with 105 μm/0.15 NA beam using x-REM diodes and a new product introduction at 200W output power from 105 μm/0.15 NA beam at 915 nm.

  6. Complete degradation of the azo dye Acid Orange-7 and bioelectricity generation in an integrated microbial fuel cell, aerobic two-stage bioreactor system in continuous flow mode at ambient temperature.

    PubMed

    Fernando, Eustace; Keshavarz, Taj; Kyazze, Godfrey

    2014-03-01

    In this study, the commercially used model azo dye Acid Orange-7 (AO-7) was fully degraded into less toxic intermediates using an integrated microbial fuel cell (MFC) and aerobic bioreactor system. The integrated bioreactor system was operated at ambient temperature and continuous-flow mode. AO-7 loading rate was varied during experiments from 70gm(-3)day(-1) to 210gm(-3)day(-1). Colour and soluble COD removal rates reached>90% under all AO-7 loading rates. The MFC treatment stage prompted AO-7 to undergo reductive degradation into its constituent aromatic amines. HPLC-MS analysis of metabolite extracts from the aerobic stage of the bioreactor system indicated further oxidative degradation of the resulting aromatic amines into simpler compounds. Bioluminescence based Vibrio fischeri ecotoxicity testing demonstrated that aerobic stage effluent exhibited toxicity reductions of approximately fivefold and ten-fold respectively compared to the dye wastewater influent and MFC-stage effluent.

  7. RTDS: A continuous, rapid, thermal synthesis mode

    SciTech Connect

    Matson, D.W.; Linehan, J.C.; Darab, J.D.; Buehler, M.F.; Phelps, M.R.; Neuenschwander, G.G.

    1995-04-01

    The Rapid Thermal Decomposition of precursors in Solution (RTDS) Process is a flow-through hydrothermal powder synthesis method capable of producing nanophase oxide and oxyhydroxide catalysts and catalyst precursors. The RTDS technique utilizes a brief exposure of dissolved precursors to high pressure/high temperature aqueous conditions to initiate crystallite nucleation. The resulting nanocrystalline suspension is removed from the hydrothermal environment through a pressure let-down device before significant crystallite growth can occur. The RTDS process is discussed as a method to produce nanocrystalline iron oxide and oxyhydroxide powders that exhibit high activity as carbon-carbon bond cleavage catalyst precursors. Nanocrystalline TiO{sub 2} and ZrO{sub 2} powders having prospective catalytic applications are also produced by the RTDS process.

  8. Lattice thermal conductivity of TixZryHf1 -x -yNiSn half-Heusler alloys calculated from first principles: Key role of nature of phonon modes

    NASA Astrophysics Data System (ADS)

    Eliassen, Simen N. H.; Katre, Ankita; Madsen, Georg K. H.; Persson, Clas; Løvvik, Ole Martin; Berland, Kristian

    2017-01-01

    In spite of their relatively high lattice thermal conductivity κℓ, the X NiSn (X =Ti , Zr, or Hf) half-Heusler compounds are good thermoelectric materials. Previous studies have shown that κℓ can be reduced by sublattice alloying on the X site. To cast light on how the alloy composition affects κℓ, we study this system using the phonon Boltzmann-transport equation within the relaxation time approximation in conjunction with density functional theory. The effect of alloying through mass-disorder scattering is explored using the virtual crystal approximation to screen the entire ternary TixZryHf1 -x -yNiSn phase diagram. The lowest lattice thermal conductivity is found for the TixHf1 -xNiSn compositions; in particular, there is a shallow minimum centered at Ti0.5Hf0.5NiSn with κℓ taking values between 3.2 and 4.1 W/mK when the Ti content varies between 20% and 80%. Interestingly, the overall behavior of mass-disorder scattering in this system can only be understood from a combination of the nature of the phonon modes and the magnitude of the mass variance. Mass-disorder scattering is not effective at scattering acoustic phonons of low energy. By using a simple model of grain boundary scattering, we find that nanostructuring these compounds can scatter such phonons effectively and thus further reduce the lattice thermal conductivity; for instance, Ti0.5Hf0.5NiSn with a grain size of L =100 nm experiences a 42% reduction of κℓ compared to that of the single crystal.

  9. Continuous Liquid Interface Production (CLIP)

    NASA Astrophysics Data System (ADS)

    Tumbleston, John

    Continuous liquid interface production (CLIP) can rapidly produce 3D parts using a range of polymeric materials. A DLP-based form of additive manufacturing, CLIP proceeds via projecting a sequence of UV images through an oxygen-permeable, UV-transparent window below a liquid resin bath. A thin uncured liquid layer, or dead zone, is created above the window and maintains a liquid interface below the advancing part. Above the dead zone, the curing part is drawn out of the resin bath creating suction forces that renew reactive liquid resin. The dead zone is created due to oxygen inhibition of photopolymerization, a process that is traditionally a nuisance in other photopolymerization applications. However, for CLIP oxygen inhibition and creation of the dead zone allows for a continuous mode of printing where UV exposure, resin renewal, and part elevation are conducted simultaneously. This continual process is fundamentally different from traditional bottom-up stereolithography printers where these steps must be conducted in separate and discrete steps. Furthermore, the relatively gentle nature of CLIP due to the established dead zone enables the use of unique materials with a wide range of mechanical properties. This presentation will showcase the CLIP technology and provide a detailed picture of interactions between different resin and process parameters. New applications for 3D printing that span the micro- to macro-scale enabled by CLIP's combination of unique materials and part production speed will also be presented.

  10. Indicators: Conductivity

    EPA Pesticide Factsheets

    Conductivity is a measure of the ability of water to pass an electrical current. Because dissolved salts and other inorganic chemicals conduct electrical current, conductivity increases as salinity increases.

  11. Power M-Mode Doppler and single-gate spectral analysis using a 2-MHz pulsed-wave Doppler transducer to directly detect cervical internal carotid artery stenosis: use of the continuity principle: report of a novel technique.

    PubMed

    Popa, Vasile N; Spencer, Merrill P; Lion, Charlene L; Felberg, Robert A

    2007-06-01

    We hypothesized that direct cervical investigation with Power M-Mode Doppler (PMD) combined with single-gate Doppler spectral analysis (SGDSA) using a 2-MHz pulsed-wave Doppler transducer would show reasonable accuracy parameters when compared with standard color-coded carotid duplex ultrasound (CDU). We prospectively screened for cervical internal carotid artery (ICA) stenosis by direct observation using a 2 MHz PMD/SGDSA device. PMD identified the artery (location, depth, flow direction) and SGDSA assessed waveform; peak systolic, end diastolic, and mean flow velocities (MFV) of the common carotid artery; cervical ICA proximally and distally; and external carotid artery. Diagnostic accuracy was compared with concurrent carotid duplex ultrasound. The continuity principle was applied using the proximal/distal cervical ICA MFV ratio. We examined 456 vessels (228 patients). Using ICA proximally/ICA distally MFV ratio of 1.5 or greater or absence of ICA signature, for 40% to 59% or greater stenosis (including occlusions), sensitivity was 75.4%, specificity 99.8%, positive predictive value 97.7%, negative predictive value 96.6%, and accuracy 96.7%. For MFV ratio 1.6 or greater or absence of ICA signature and 60% to 79% or greater stenosis (including occlusions), sensitivity was 92.3%, specificity 98.1%, positive predictive value 81.8%, negative predictive value 99.3%, and accuracy 97.6%. Use of combined PMD and SGDSA to directly observe the extracranial ICA is reasonably accurate compared with carotid duplex ultrasound. Using the MFV ratio of proximal/distal extracranial ICA improves accuracy parameters and provides a quick and effective bedside screen for ICA stenosis. This novel technique should be considered part of the standard PMD/transcranial Doppler examination.

  12. Conductance of Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Datta, Supriyo; Anatram, M. P.

    1998-01-01

    The recent report of quantized conductance in a 4 m long multiwalled nanotube (MWNT) raises the exciting possibility of ballistic transport at room temperature over relatively long distances. We argue that this is made possible by the special symmetry of the eigenstates of the lowest propagating modes in metallic nanotubes which suppresses backscattering. This unusual effect is absent for the higher propagating modes so that transport is not ballistic once the bias exceeds the cut-off energy for the higher modes, which is estimated to be approximately 75 meV for nanotubes of diameter approximately 15 nm. Also, we show that the symmetry of the eigenstates can significantly affect their coupling to the reservoir and hence the contact resistance. A simple model is presented that can be used to understand the observed conductance-voltage characteristics.

  13. Effect of the transverse parasitic mode on beam performance for the ADS driver linac in China

    NASA Astrophysics Data System (ADS)

    Cheng, Peng; Pei, Shi-Lun; Wang, Jiu-Qing; Li, Zhi-Hui

    2015-05-01

    The ADS (Accelerator Driven subcritical System) driver linac in China is designed to run in CW (Continuous Wave) mode with 10 mA designed beam current. In this scenario, the beam-induced parasitic modes in the ADS driver linac may make the beam unstable or deteriorate the beam performance. To evaluate the parasitic mode effect on the beam dynamics systematically, simulation studies using the ROOT-based numerical code SMD have been conducted. The longitudinal beam instability induced by the HOMs (High Order Modes) and SOMs (Same Order Modes) has little effect on the longitudinal beam performance for the current ADS driver linac design based on the 10 MeV/325 MHz injector I from previous studies. Here the transverse parasitic mode (i.e., dipole HOM) effect on the transverse beam performance at the ADS driver linac exit is investigated. To more reasonably quantify the dipole mode effect, the multi-bunch effective emittance is introduced in this paper.

  14. Electrical Conductivity.

    ERIC Educational Resources Information Center

    Allen, Philip B.

    1979-01-01

    Examines Drude's classical (1900) theory of electrical conduction, details the objections to and successes of the 1900 theory, and investigates the Quantum (1928) theory of conduction, reviewing its successes and limitations. (BT)

  15. Electrical Conductivity.

    ERIC Educational Resources Information Center

    Allen, Philip B.

    1979-01-01

    Examines Drude's classical (1900) theory of electrical conduction, details the objections to and successes of the 1900 theory, and investigates the Quantum (1928) theory of conduction, reviewing its successes and limitations. (BT)

  16. Section 1. Method of determining mode shapes and natural frequencies of the NASA unmodified test structure. Section 2. Continuous beam closed from solution to the NASA-LSS astromast torsional vibration, appendix E

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The methods used to determine the lower natural frequencies and their corresponding mode shapes of the NASA-LSS Astromast (Unmodified Test Structure), and the mass integrals associated with the mode shapes are illustrated. The test structure is modeled as a cantilever beam with 91 lumped masses and without the tip mass on the free end of the bram. This uncouples the torsion and bending modes and allows for them to be determined separately. The frequency range was limited to an upper bound of 100 rad/sec (15.92 Hz.). In this range from 0.-100. rad/sec, three bending frequencies and one torsion frequency was found.

  17. On the effect of viscosity and thermal conductivity on sound propagation in ducts: A re-visit to the classical theory with extensions for higher order modes and presence of mean flow

    NASA Astrophysics Data System (ADS)

    Dokumaci, Erkan

    2014-10-01

    The dispersion equation for the axisymmetric modes of viscothermal acoustic wave propagation in uniform hard-walled circular ducts containing a quiescent perfect gas is classical. This has been extended to cover the non-axisymmetric modes and real fluids in contemporary studies. The fundamental axisymmetric mode has been the subject of a large number of studies proposing approximate solutions and the characteristics of the propagation constants for narrow and wide ducts with or without mean flow is well understood. In contrast, there are only few publications on the higher order modes and the current knowledge about their propagation characteristics is rather poor. On the other hand, there is a void of papers in the literature on the effect of the mean flow on the quiescent modes of propagation. The present paper aims to contribute to the filling of these gaps to some extent. The classical theory is re-considered with a view to cover all modes of acoustic propagation in circular ducts carrying a real fluid moving axially with a uniform subsonic velocity. The analysis reveals a new branch of propagation constants for the axisymmetric modes, which appears to have escaped attention hitherto. The solution of the governing wave equation is expressed in a modal transfer matrix form in frequency domain and numerical results are presented to show the effects over wide ranges of frequency, viscosity and mean flow parameters on the propagation constants. The theoretical formulation allows for the duct walls to have finite impedance, but no numerical results are presented for lined ducts or ducts carrying a sheared mean flow.

  18. Mixed-mode acrylamide-based continuous beds bearing tert-butyl groups for capillary electrochromatography synthesized via complexation of N-tert-butylacrylamide with a water-soluble cyclodextrin. Part I: Retention properties.

    PubMed

    Al-Massaedh, Ayat Allah; Pyell, Ute

    2016-12-16

    With the aim to improve the understanding of morphology and efficiency properties, we investigate in this series the impact of the complex formation constant of the hydrophobic monomer with respect to statistically methylated-β-cyclodextrin (Me-β-CD) on the electrochromatographic properties of highly crosslinked amphiphilic mixed-mode acrylamide-based monolithic stationary phases. Based on our previous work on amphiphilic mixed-mode monolithic stationary phases for capillary electrochromatography (CEC) using N-(1-adamantyl)acrylamide (Ad-AAm) as hydrophobic monomer that forms an extremely strong water-soluble inclusion complex with Me-β-CD, we now selected N-tert-butylacrylamide (NTBA) as hydrophobic monomer forming an inclusion complex with Me-β-CD with a much lower value of the formation constant. Mixed-mode monolithic stationary phases are synthesized by in-situ free radical copolymerization of cyclodextrin-solubilized N-tert-butylacrylamide, a water soluble crosslinker (piperazinediacrylamide), a hydrophilic neutral monomer (methacrylamide), and a negatively charged monomer (vinylsulfonic acid) in aqueous medium in bind silane pre-treated fused silica capillaries. The synthesized monolithic stationary phases have both hydrophobic and hydrophilic moieties and can be employed in the reversed-phase mode, in the normal-phase mode, in a mixed-mode or in the hydrophilic interaction liquid chromatography (HILIC) mode (depending on the composition of the mobile phase and on the properties of the solute). Morphology and retention properties of this new type of stationary phase are compared to those reported in our previous series. With a homologues series of alkylphenones it is confirmed that the hydrophobicity (methylene selectivity αmeth) of the stationary phase is strongly dependent on the type of hydrophobic monomer employed. The studies reveal a significant influence of the formation constant of the involved host-guest inclusion complex on the morphology (i

  19. Continuous Problem of Function Continuity

    ERIC Educational Resources Information Center

    Jayakody, Gaya; Zazkis, Rina

    2015-01-01

    We examine different definitions presented in textbooks and other mathematical sources for "continuity of a function at a point" and "continuous function" in the context of introductory level Calculus. We then identify problematic issues related to definitions of continuity and discontinuity: inconsistency and absence of…

  20. Continuous Problem of Function Continuity

    ERIC Educational Resources Information Center

    Jayakody, Gaya; Zazkis, Rina

    2015-01-01

    We examine different definitions presented in textbooks and other mathematical sources for "continuity of a function at a point" and "continuous function" in the context of introductory level Calculus. We then identify problematic issues related to definitions of continuity and discontinuity: inconsistency and absence of…

  1. Continuation Education.

    ERIC Educational Resources Information Center

    Fremont Unified School District, CA.

    The Fremont, California Unified School District organized a continuing education program through a workshop held in the summer of 1968. This paper presents the results of that workshop. Following a statement of philosophy, an outline of the characteristics of the continuation student, and an outline of the functions of the program, an overview of…

  2. Conduct disorder

    MedlinePlus

    ... activity. Causes Conduct disorder has been linked to: Child abuse Drug or alcohol abuse in the parents Family ... 2016:chap 23. Read More Antisocial personality disorder Child abuse - physical Review Date 3/4/2015 Updated by: ...

  3. Electrical Conductivity.

    ERIC Educational Resources Information Center

    Hershey, David R.; Sand, Susan

    1993-01-01

    Explains how electrical conductivity (EC) can be used to measure ion concentration in solutions. Describes instrumentation for the measurement, temperature dependence and EC, and the EC of common substances. (PR)

  4. Conduct Disorder

    MedlinePlus

    ... brain damage, child abuse or neglect, genetic vulnerability, school failure, and traumatic life experiences . Children or adolescents with conduct disorder may exhibit some of the following behaviors: Aggression to people and animals bullies , threatens or intimidates ...

  5. Electrical Conductivity.

    ERIC Educational Resources Information Center

    Hershey, David R.; Sand, Susan

    1993-01-01

    Explains how electrical conductivity (EC) can be used to measure ion concentration in solutions. Describes instrumentation for the measurement, temperature dependence and EC, and the EC of common substances. (PR)

  6. Violin plate modes.

    PubMed

    Gough, Colin

    2015-01-01

    As the first step toward developing a generic model for the acoustically radiating vibrational modes of the violin and related instruments, the modes of both freely supported and edge-constrained top and back plates have been investigated as functions of shape, arching height, elastic anisotropy, the f-holes and associated island area, thickness graduations, and the additional boundary constraints of the ribs, soundpost, and bass-bar present in the assembled instrument. Comsol shell structure finite element software has been used as a quasi-experimental tool, with physical and geometric properties varied smoothly, often over several orders of magnitude, allowing the development of the plate modes to be followed continuously from those of an initially square plate to those of doubly-arched, guitar-shaped, orthotropic plates and their dependence on all the above factors.

  7. Multi-mode horn

    NASA Technical Reports Server (NTRS)

    Neilson, Jeffrey M. (Inventor)

    2002-01-01

    A horn has an input aperture and an output aperture, and comprises a conductive inner surface formed by rotating a curve about a central axis. The curve comprises a first arc having an input aperture end and a transition end, and a second arc having a transition end and an output aperture end. When rotated about the central axis, the first arc input aperture end forms an input aperture, and the second arc output aperture end forms an output aperture. The curve is then optimized to provide a mode conversion which maximizes the power transfer of input energy to the Gaussian mode at the output aperture.

  8. Mode-mode fiber interferometer with impact localization ability

    NASA Astrophysics Data System (ADS)

    Kotov, Oleg; Chapalo, Ivan

    2016-04-01

    In this publication we investigate distributed mode-mode fiber interferometer (MFI) with ability of external impact localization. It is based on bidirectional continuous selective excitation of multimode fiber (MMF) with increasing of launched modes quantity along the MMF from excitation point to the opposite end of fiber. Two photo detection systems register output signals from both directions. MFI output signal characteristics such as amplitude and spectrum width depend on excited modes quantity at the point of perturbation. Thus, every fiber point is characterized by two opposite direction signal parameters. Calculating these parameters' values makes it possible to localize the segment subjected by external impact. Experimental MFI setup include 3 MMF segments with 2 mode controllers among them which increase excited modes number from segment to segment. During the experiment, every MMF segment was subjected by arbitrary external perturbations and output signals were analyzed. Obtained results confirmed the ability of localization.

  9. Mode evolution in polarization maintain few mode fibers and applications in mode-division-multiplexing systems

    NASA Astrophysics Data System (ADS)

    Li, Yan; Zeng, Xinglin; Mo, Qi; Li, Wei; Liu, Zhijian; Wu, Jian

    2016-10-01

    In few-mode polarization-maintaining-fiber (FM-PMF), the effective-index splitting exists not only between orthogonally polarization state but also between degenerated modes within a high-order mode group. Hence besides the polarization state evolution, the mode patterns in each LP set are need to be analyzed. In this letter, the completed firstorder mode (LP11 mode) evolution in PM-FMF is analyzed and represented by analogous Jones vector and Poincarésphere respectively. Furthermore, with Jones matrix analysis, the modal dynamics in FM-PMFs is conveniently analyzed. The conclusions are used to propose a PM-FMF based LP11 mode rotator and an PM-FMF based OAM generator. Both simulation and experiments are conducted to investigate performance of the two devices.

  10. STUDY OF A 10-MW CONTINUOUS SPALLATION NEUTRON SOURCE.

    SciTech Connect

    RUGGIERO,A.G.LUDEWIG,H.SHAPIRO,S.

    2003-05-12

    This paper reports on the feasibility study of a proton Super-Conducting Linac as the driver for an Accelerator-based Continuous Neutron Source (ACNS) [1] to be located at Brookhaven National Laboratory (BNL). The Linac is to be operated in the Continuous Wave (CW) mode to produce an average 10 MW of beam power. The Linac beam energy is taken to be 1.25 GeV. The required average proton beam intensity in exit is then 8 mA.

  11. Appropriate Conduct

    ERIC Educational Resources Information Center

    Di Lullo, Louis

    2004-01-01

    Many years ago when the author assumed the role of assistant principal for school climate, discipline, and attendance, he inherited many school policies and guidelines that were outdated, unfair, and without merit in the current school climate. Because the school conduct code had not been revised since the school opened in 1960, many of the…

  12. Appropriate Conduct

    ERIC Educational Resources Information Center

    Di Lullo, Louis

    2004-01-01

    Many years ago when the author assumed the role of assistant principal for school climate, discipline, and attendance, he inherited many school policies and guidelines that were outdated, unfair, and without merit in the current school climate. Because the school conduct code had not been revised since the school opened in 1960, many of the…

  13. Conduction apraxia.

    PubMed Central

    Ochipa, C; Rothi, L J; Heilman, K M

    1994-01-01

    A left hemisphere damaged patient with ideomotor apraxia is described, whose performance on pantomime to verbal command was superior to pantomime imitation. His reception of these same gestures (gesture naming) was spared. This syndrome has been named conduction apraxia. To account for this selective impaired performance on gesture imitation, a separation of the representations for gesture production and reception is proposed and a non-lexical gesture processing route for gesture imitation is suggested. Images PMID:7931387

  14. Preventing Fire Death and Injury, Conducting a Fire Drill in a Group Home [and] When You Need a Fire Safety Expert. National Fire Safety Certification System. Continuing Education Program. Volume 1, Numbers 1-3.

    ERIC Educational Resources Information Center

    Walker, Bonnie

    Three booklets provide fire safety information for staff of residential facilities serving people with developmental disabilities. Booklets focus on: (1) preventing fire death and injury, (2) conducting a fire drill in a group home, and (3) the role of fire safety experts. The first booklet stresses the elimination of the following dangers:…

  15. Calculus Student Understanding of Continuity

    ERIC Educational Resources Information Center

    Wangle, Jayleen Lillian

    2013-01-01

    Continuity is a central concept in calculus. Yet very few students seem to understand the nature of continuity. The research described was conducted in two stages. Students were asked questions in multiple choice and true/false format regarding function, limit and continuity. These results were used to identify participants as strong, weak or…

  16. Continuing Education Students.

    ERIC Educational Resources Information Center

    Piatt, Virginia; Seybert, Jeff

    An in-class survey of 683 continuing education students was conducted at Johnson County Community College (JCCC) to obtain information on: (1) student characteristics, including age, sex, family characteristics, income, educational background, occupation, area of residence, distance to class, sources of information about JCCC, and method of…

  17. Continuing Education Survey.

    ERIC Educational Resources Information Center

    Bird, K. A.; Fenwick, P. R.

    In 1978, a national survey was conducted in New Zealand to determine the extent of participation in continuing education and the level of unmet need for these activities. A questionnaire was developed dealing with respondent characteristics, spare time and interests, agency-directed learning activities (ADLAS), and unmet needs, and administered to…

  18. Continuing Education in Nursing.

    ERIC Educational Resources Information Center

    Curtis, Frieda Smith; And Others

    This book is planned to provide guidance for nurses in planning, conducting, and evaluating programs of continuing education; content is built on the collective experiences and thinking of a regional group of nurse educators engaged in developing a coordinated program for a large geographical area. After discussion of changing patterns of health…

  19. Mode selection in square resonator microlasers for widely tunable single mode lasing.

    PubMed

    Tang, Ming-Ying; Sui, Shao-Shuai; Yang, Yue-De; Xiao, Jin-Long; Du, Yun; Huang, Yong-Zhen

    2015-10-19

    Mode selection in square resonator semiconductor microlasers is demonstrated by adjusting the width of the output waveguide coupled to the midpoint of one side. The simulation and experimental results reveal that widely tunable single mode lasing can be realized in square resonator microlasers. Through adjusting the width of the output waveguide, the mode interval of the high-Q modes can reach four times of the longitudinal mode interval. Therefore, mode hopping can be efficiently avoided and the lasing wavelength can be tuned continuously by tuning the injection current. For a 17.8-μm-side-length square microlaser with a 1.4-μm-width output waveguide, mode-hopping-free single-mode operation is achieved with a continuous tuning range of 9.2 nm. As a result, the control of the lasing mode is realized for the square microlasers.

  20. Continuing Through Iani Chaos

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site]

    The THEMIS VIS camera is capable of capturing color images of the Martian surface using five different color filters. In this mode of operation, the spatial resolution and coverage of the image must be reduced to accommodate the additional data volume produced from using multiple filters. To make a color image, three of the five filter images (each in grayscale) are selected. Each is contrast enhanced and then converted to a red, green, or blue intensity image. These three images are then combined to produce a full color, single image. Because the THEMIS color filters don't span the full range of colors seen by the human eye, a color THEMIS image does not represent true color. Also, because each single-filter image is contrast enhanced before inclusion in the three-color image, the apparent color variation of the scene is exaggerated. Nevertheless, the color variation that does appear is representative of some change in color, however subtle, in the actual scene. Note that the long edges of THEMIS color images typically contain color artifacts that do not represent surface variation.

    This false color image continues the northward trend through the Iani Chaos region. Compare this image to Monday's and Tuesday's. This image was collected during the Southern Fall season.

    Image information: VIS instrument. Latitude -0.1 Longitude 342.6 East (17.4 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001

  1. Hardware Assisted ROP Detection Mode (HARD Mode)

    DTIC Science & Technology

    2013-08-01

    Distribution A. Cleared for public release; unlimited distribution. USAFA-CN-2013-457 Hardware Assisted ROP Detection Mode (HARD Mode) NATHANIEL HART...457 This report, "Hardware Assisted ROP Detection Mode (HARD Mode)" is presented as a competent treatment of the subj ect, worthy of publication. The...Technical 20120810-20121215 Hardware Assisted ROP Detection Mode (HARD Mode) NATHANIEL HART MICHAEL WINSTEAD MARTIN CARLISLE RODNEY LYKINS MICHAEL

  2. Tilting and shifting modes in a spheromak

    SciTech Connect

    Jardin, S.C.; Chance, M.S.; Dewar, R.L.; Grimm, R.C.; Monticello, D.A.

    1981-04-01

    In the absence of a conducting wall, typical spheromak plasmas are unstable to tilting and/or shifting modes. The effects of the cross-sectional shape, aspect ratio, and the location of a conducting wall on the stability of these modes are investigated.

  3. Conducting a thermal conductivity survey

    NASA Technical Reports Server (NTRS)

    Allen, P. B.

    1985-01-01

    A physically transparent approximate theory of phonon decay rates is presented starting from a pair potential model of the interatomic forces in an insulator or semiconductor. The theory applies in the classical regime and relates the 3-phonon decay rate to the third derivative of the pair potential. Phonon dispersion relations do not need to be calculated, as sum rules relate all the needed quantities directly to the pair potential. The Brillouin zone averaged phonon lifetime turns out to involve a dimensionless measure of the anharmonicity multiplied by an effective density of states for 3-phonon decay. Results are given for rare gas and alkali halide crystals. For rare gases, the results are in good agreement with more elaborate perturbation calculations. Comparison to experimental data on phonon linewidths and thermal conductivity are made.

  4. The better of two evils? Evidence that children exhibiting continuous conduct problems high or low on callous-unemotional traits score on opposite directions on physiological and behavioral measures of fear.

    PubMed

    Fanti, Kostas A; Panayiotou, Georgia; Lazarou, Chrysostomos; Michael, Raphaelia; Georgiou, Giorgos

    2016-02-01

    The present study examines whether heterogeneous groups of children identified based on their longitudinal scores on conduct problems (CP) and callous-unemotional (CU) traits differ on physiological and behavioral measures of fear. Specifically, it aims to test the hypothesis that children with high/stable CP differentiated on CU traits score on opposite directions on a fear-fearless continuum. Seventy-three participants (M age = 11.21; 45.2% female) were selected from a sample of 1,200 children. Children and their parents completed a battery of questionnaires assessing fearfulness, sensitivity to punishment, and behavioral inhibition. Children also participated in an experiment assessing their startle reactivity to fearful mental imagery, a well-established index of defensive motivation. The pattern of results verifies the hypothesis that fearlessness, assessed with physiological and behavioral measures, is a core characteristic of children high on both CP and CU traits (i.e., receiving the DSM-5 specifier of limited prosocial emotions). To the contrary, children with high/stable CP and low CU traits demonstrated high responsiveness to fear, high behavioral inhibition, and high sensitivity to punishment. The study is in accord with the principle of equifinality, in that different developmental mechanisms (i.e., extremes of high and low fear) may have the same behavioral outcome manifested as phenotypic antisocial behavior.

  5. Coupled-Mode Theory derivation of the formal equivalence between a three-mode waveguide and a set of three mutually coupled single-mode waveguides

    NASA Astrophysics Data System (ADS)

    Boucher, Yann G.

    2017-03-01

    The formal identification between a two-mode waveguide and a system of two mutually coupled single-mode waveguides stems from the symmetries of the evolution operator. When the gap tends to zero, the super-modes of the coupled system merge continuously into the modes of the multimode waveguide. For modelling purposes, it is very tempting to extend the analogy to three-mode waveguides (and beyond). But not without some precautions…

  6. 5 CFR 735.203 - What are the restrictions on conduct prejudicial to the Government?

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... (CONTINUED) CIVIL SERVICE REGULATIONS (CONTINUED) EMPLOYEE RESPONSIBILITIES AND CONDUCT Standards of Conduct... engage in criminal, infamous, dishonest, immoral, or notoriously disgraceful conduct, or other...

  7. Nursing essential principles: continuous renal replacement therapy.

    PubMed

    Richardson, Annette; Whatmore, Jayne

    2015-01-01

    This article aims to guide critical care nurses with the care and management of patients on continuous renal replacement therapy (CRRT). CRRT, a highly specialized therapy involving complex nursing care, is used widely in the intensive care unit to treat patients with acute kidney injury. A literature search was conducted using CINAHL, Medline from PubMed and BNI using the search terms CRRT or continuous veno-venous haemofiltration and nursing or nurses from 2000 onwards and limited to the English language. The appraised evidence and expert opinion is used in this article. Four essential nursing principles for CRRT are reviewed (1) the importance of continuous assessment of the indications to influence the appropriate mode; (2) ensuring good vascular access; (3) the avoidance of unnecessary interruptions and (4) the prevention of complications. The identified four essential nursing principles provide guidance on this complex aspects of nursing practice. Specific nursing research to guide the care and management of this therapy is limited so should be explored in the future. Critical care nurses caring for and managing patients on CRRT require an understanding of how to deliver safe CRRT. © 2014 British Association of Critical Care Nurses.

  8. Geodesic acoustic modes with poloidal mode couplings ad infinitum

    NASA Astrophysics Data System (ADS)

    Singh, Rameswar; Gürcan, Ö. D.

    2017-02-01

    Geodesic acoustic modes (GAMs) are studied including all poloidal mode (m) couplings within a drift reduced Braginskii framework. An exact analytical formula for GAM frequency is given within the toroidal Hasegawa Mima model with the full finite larmor radius effect and poloidal mode couplings ad infinitum using a scalar continued fraction formulation, which results from reduction of the semi-infinite chain of interactions that is obtained from the nearest neighbor coupling pattern due to geodesic curvature. This pattern can be described by a semi-infinite chain model of the GAM with the mode-mode coupling matrix elements proportional to the radial wave number kr. In the more general case of multi-field description of the GAM, the infinite chain can be reduced to a renormalized bi-nodal chain with a matrix continued fraction formulation. The convergence study of the linear GAM dispersion with respect to kr and the m-spectra confirms that the coupling beyond m = 1 is sustained only when kr ≠ 0 and the higher m couplings become important with increasing kr and increasing ion to electron temperature ratio τi.

  9. Nondestructive verification of continuous-variable entanglement

    NASA Astrophysics Data System (ADS)

    de Faria, Alencar J.

    2016-07-01

    An optical procedure in the context of continuous variables to verify bipartite entanglement without destroying both systems and their entanglement is proposed. To perform the nondestructive verification of entanglement, the method relies on beam-splitter and quantum nondemolition (QND) interactions of the signal modes with two ancillary probe modes. The probe modes are measured by homodyne detections, and the obtained information is used to feed forward modulation of signal modes, concluding the procedure. Characterizing the method by figures of merit used in QND processes, we can establish the conditions for an effectively quantum scheme. Based on such conditions, it is shown that the classical information acquired from the homodyne detections of probe modes is sufficient to verify the entanglement of the output signal modes. The processing impact due to added noise on the output entanglement is assessed in the case of Gaussian modes.

  10. Nucleation mode formation in heavy-duty diesel exhaust with and without a particulate filter.

    PubMed

    Vaaraslahti, Kati; Virtanen, Annele; Ristimäki, Jyrki; Keskinen, Jorma

    2004-09-15

    Particle size distribution measurement with direct tailpipe sampling is employed to study the effect of a continuously regenerating diesel particulate filter (CRDPF) on emissions of a heavy-duty diesel engine. The CRDPF consists of an oxidation catalyst and a filter. Tests are conducted using 2 and 40 ppm sulfur content fuels and two steady-state driving modes. The formation of nucleation mode with and without CRDPF is found to depend on different parameters. Without after-treatment, size distribution is observed to have a nucleation mode only at low load. Being independent of the fuel sulfur level (with these low sulfur level fuels), this nucleation mode is suggested to form mainly from hydrocarbons. With a CRDPF-equipped engine, nucleation mode, which was not observed without CRDPF, was found at high load mode only. This nucleation mode formation was found to correlate positively with fuel sulfur content. It is suggested that sulfuric acid is a main nucleating species in this situation, resulting from the effective conversion of SO2 to SO3 in the oxidation catalyst. Using a thermodenuder confirms that the nucleation mode particles are semivolatile in nature.

  11. Extending Mode Areas of Single-mode All-solid Photonic Bandgap Fibers

    DTIC Science & Technology

    2015-04-02

    course of developing high-power fiber lasers, mode area scaling is a key to mitigate nonlinear effects as a result of high optical intensity, such...demonstrated a singlemode photonic bandgap fiber with record effective mode area of ~2650?m2. Detailed numeric studies have been conducted for multiple... effective mode areas. We have also experimentally validated one of the designs. M2ə.08 across the transmission band was demonstrated. Extending Mode

  12. Culture modes and financial evaluation of two oleaginous microalgae for biodiesel production in desert area with open raceway pond.

    PubMed

    He, Qiaoning; Yang, Haijian; Hu, Chunxiang

    2016-10-01

    Cultivation modes of autotrophic microalgae for biodiesel production utilizing open raceway pond were analyzed in this study. Five before screened good microalgae were tested their lipid productivity and biodiesel quality again in outdoor 1000L ORP. Then, Chlorella sp. L1 and Monoraphidium dybowskii Y2 were selected due to their stronger environmental adaptability, higher lipid productivity and better biodiesel properties. Further scale up cultivation for two species with batch and semi-continuous culture was conducted. In 40,000L ORP, higher lipid productivity (5.15 versus 4.06gm(-2)d(-1) for Chlorella sp. L1, 5.35 versus 3.00gm(-2)d(-1) for M. dybowskii Y2) was achieved in semi-continuous mode. Moreover, the financial costs of 14.18$gal(-1) and 13.31$gal(-1) for crude biodiesel in two microalgae with semi-continuous mode were more economically feasible for commercial production on large scale outdoors.

  13. 7 CFR 97.157 - Professional conduct.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) COMMODITY LABORATORY TESTING PROGRAMS... appearing before the Office shall conform to the standards of ethical and professional conduct,...

  14. A study of different modes of charge transfer to ground in upward lightning

    NASA Astrophysics Data System (ADS)

    Zhou, Helin; Rakov, Vladimir A.; Diendorfer, Gerhard; Thottappillil, Rajeev; Pichler, Hannes; Mair, Martin

    2015-04-01

    We examined simultaneous measurements of currents and close electric field changes, as well as high-speed video images, associated with pulses superimposed on the initial continuous current (ICC pulses) and M-components following return strokes in upward flashes initiated from the Gaisberg Tower in Austria. For tower-initiated lightning, upward leaders often create multiple branches below the cloud base that can facilitate initiation of transients at relatively low heights along the grounded channel carrying ICC of some tens to hundreds of amperes. In this situation, a conducting channel is present, which is necessary for the M-component mode of charge transfer to ground, but the excitation wave (leader), after entering the channel, cannot form a long-front downward M-wave, because of the relatively short distance between the entry (junction) point and the strike-object top. Clearly, two parallel channels, one previously existing and the other newly formed (or rejuvenated) are involved in the charge transfer, and there is a common channel section between the junction point and the strike object. We use the term "mixed mode of charge transfer to ground", to indicate that in the case of low junction point the "classical" M-component mode is not possible, even though a conducting channel to ground (an attribute of the M-component mode) is present. The mixed mode scenario is also applicable to impulsive processes during continuing currents following return strokes in upward lightning.

  15. Lanczos modes for reduced-order control of flexible structures

    NASA Technical Reports Server (NTRS)

    Craig, Roy R., Jr.; Turner, Russell M.

    1987-01-01

    Lanczos mode models represent low-frequency forced response better than do normal mode models and can be developed for both continuous and finite element structural representations. It was recommended that Lanczos mode models for systems with multiple input and/or rigid body modes should be developed; numerical stability of the Lanczos algorithm should be assessed; and control system designs employing the Lanczos mode models should be attempted.

  16. Conducting the Heat

    NASA Technical Reports Server (NTRS)

    2003-01-01

    Heat conduction plays an important role in the efficiency and life span of electronic components. To keep electronic components running efficiently and at a proper temperature, thermal management systems transfer heat generated from the components to thermal surfaces such as heat sinks, heat pipes, radiators, or heat spreaders. Thermal surfaces absorb the heat from the electrical components and dissipate it into the environment, preventing overheating. To ensure the best contact between electrical components and thermal surfaces, thermal interface materials are applied. In addition to having high conductivity, ideal thermal interface materials should be compliant to conform to the components, increasing the surface contact. While many different types of interface materials exist for varying purposes, Energy Science Laboratories, Inc. (ESLI), of San Diego, California, proposed using carbon velvets as thermal interface materials for general aerospace and electronics applications. NASA s Johnson Space Center granted ESLI a Small Business Innovation Research (SBIR) contract to develop thermal interface materials that are lightweight and compliant, and demonstrate high thermal conductance even for nonflat surfaces. Through Phase II SBIR work, ESLI created Vel-Therm for the commercial market. Vel-Therm is a soft, carbon fiber velvet consisting of numerous high thermal conductivity carbon fibers anchored in a thin layer of adhesive. The velvets are fabricated by precision cutting continuous carbon fiber tows and electrostatically flocking the fibers into uncured adhesive, using proprietary techniques.

  17. Solar Doppler shifts - Sources of continuous spectra

    NASA Technical Reports Server (NTRS)

    Duvall, T. L., Jr.; Harvey, J. W.

    1986-01-01

    Oscillation observations can be used to study nonoscillatory solar phenomena that exhibit Doppler shifts. The paper discusses several effects of these phenomena and their associated temporal and spatial power spectra: (1) they limit the signal-to-noise ratio and sometimes detectability of oscillation modes; (2) there is the potential for better understanding and/or detection of solar phenomena; (3) large-scale convection may spatially modulate oscillation modes, leading to a continuous background spectrum; and (4) in regions of the spectrum where the resolution to separate modes is lacking one can determine upper limits for the integrated effects of modes.

  18. SAMPEX Spin Stabilized Mode

    NASA Technical Reports Server (NTRS)

    Tsai, Dean C.; Markley, F. Landis; Watson, Todd P.

    2008-01-01

    The Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX), the first of the Small Explorer series of spacecraft, was launched on July 3, 1992 into an 82' inclination orbit with an apogee of 670 km and a perigee of 520 km and a mission lifetime goal of 3 years. After more than 15 years of continuous operation, the reaction wheel began to fail on August 18,2007. With a set of three magnetic torquer bars being the only remaining attitude actuator, the SAMPEX recovery team decided to deviate from its original attitude control system design and put the spacecraft into a spin stabilized mode. The necessary operations had not been used for many years, which posed a challenge. However, on September 25, 2007, the spacecraft was successfully spun up to 1.0 rpm about its pitch axis, which points at the sun. This paper describes the diagnosis of the anomaly, the analysis of flight data, the simulation of the spacecraft dynamics, and the procedures used to recover the spacecraft to spin stabilized mode.

  19. Trapped modes in zigzag graphene nanoribbons

    NASA Astrophysics Data System (ADS)

    Kozlov, V. A.; Nazarov, S. A.; Orlof, A.

    2017-08-01

    We study the scattering on an ultra-low potential in zigzag graphene nanoribbon. Using a mathematical framework based on the continuous Dirac model and the augmented scattering matrix, we derive a condition for the existence of a trapped mode. We consider the threshold energies where the continuous spectrum changes its multiplicity and show that the trapped modes may appear for energies slightly less than a threshold and that its multiplicity does not exceeds one. We prove that trapped modes do not appear outside the threshold, provided the potential is sufficiently small.

  20. Internal tilting mode stability of non-sperical spheromak

    SciTech Connect

    Yamazaki, K.

    1980-06-01

    Fixed boundary tilting mode stability is analyzed for spheromak with arbitrarily shaped cross section. A prolate spheromak can be stabilized against tilting mode by adding a conducting shell of triangular or trapesoidal half-cross section.

  1. Double mode Cepheids in M31

    SciTech Connect

    Poleski, Radosław

    2013-12-01

    Until now, double mode Cepheids (or beat Cepheids) were known only in the Galaxy, the Magellanic Clouds, and M33. Curiously, none of the more than 2000 Cepheids in M31 was claimed to show two pulsation modes. We conducted a systematic search for double mode Cepheids in the archival data of M31 and discovered four such objects. We identify one of the stars as a first and second overtone pulsator even though its secondary period is subject to strong aliasing. Two stars pulsate in the fundamental mode and the first overtone. Their fundamental periods are 9.392 days and 9.163 days. This makes them the first candidates for fundamental mode and first overtone Cepheids, of which double mode pulsations are caused by the 2:1 resonance of the fundamental mode and the second overtone.

  2. Mode coupling in hybrid square-rectangular lasers for single mode operation

    SciTech Connect

    Ma, Xiu-Wen; Huang, Yong-Zhen Yang, Yue-De; Xiao, Jin-Long; Weng, Hai-Zhong; Xiao, Zhi-Xiong

    2016-08-15

    Mode coupling between a square microcavity and a Fabry-Pérot (FP) cavity is proposed and demonstrated for realizing single mode lasers. The modulations of the mode Q factor as simulation results are observed and single mode operation is obtained with a side mode suppression ratio of 46 dB and a single mode fiber coupling loss of 3.2 dB for an AlGaInAs/InP hybrid laser as a 300-μm-length and 1.5-μm-wide FP cavity connected to a vertex of a 10-μm-side square microcavity. Furthermore, tunable single mode operation is demonstrated with a continuous wavelength tuning range over 10 nm. The simple hybrid structure may shed light on practical applications of whispering-gallery mode microcavities in large-scale photonic integrated circuits and optical communication and interconnection.

  3. Mode coupling in hybrid square-rectangular lasers for single mode operation

    NASA Astrophysics Data System (ADS)

    Ma, Xiu-Wen; Huang, Yong-Zhen; Yang, Yue-De; Xiao, Jin-Long; Weng, Hai-Zhong; Xiao, Zhi-Xiong

    2016-08-01

    Mode coupling between a square microcavity and a Fabry-Pérot (FP) cavity is proposed and demonstrated for realizing single mode lasers. The modulations of the mode Q factor as simulation results are observed and single mode operation is obtained with a side mode suppression ratio of 46 dB and a single mode fiber coupling loss of 3.2 dB for an AlGaInAs/InP hybrid laser as a 300-μm-length and 1.5-μm-wide FP cavity connected to a vertex of a 10-μm-side square microcavity. Furthermore, tunable single mode operation is demonstrated with a continuous wavelength tuning range over 10 nm. The simple hybrid structure may shed light on practical applications of whispering-gallery mode microcavities in large-scale photonic integrated circuits and optical communication and interconnection.

  4. Mode Contributions to the Casimir Effect

    NASA Astrophysics Data System (ADS)

    Intravaia, F.; Henkel, C.

    2010-04-01

    Applying a sum-over-modes approach to the Casimir interaction between two plates with finite conductivity, we isolate and study the contributions of surface plasmons and Foucault (eddy current) modes. We show in particular that for the TE-polarization eddy currents provide a repulsive force that cancels, at high temperatures, the Casimir free energy calculated with the plasma model.

  5. Ion conductance in electrolyte solutions

    NASA Astrophysics Data System (ADS)

    Chandra, Amalendu; Bagchi, Biman

    1999-05-01

    We develop a new theoretical formulation to study ion conductance in electrolyte solutions, based on a mode coupling theory treatment of the electrolyte friction. The new theory provides expressions for both the ion atmosphere relaxation and electrophoretic contributions to the total electrolyte friction that acts on a moving ion. While the ion atmosphere relaxation term arises from the time-dependent microscopic interaction of the moving ion with the surrounding ions in the solution, the electrophoretic term originates from the coupling of the ion's velocity to the collective current mode of the ion atmosphere. Mode coupling theory, combined with time-dependent density functional theory of ion atmosphere fluctuations, leads to self-consistent expressions for these two terms which also include the effects of self-motion of the ion under consideration. These expressions have been solved for the concentration dependence of electrolyte friction and ion conductance. It is shown that in the limit of very low ion concentration, the present theory correctly reduces to the well-known Debye-Huckel-Onsager limiting law which predicts a linear dependence of conductance on the square root of ion concentration (c). At moderate and high concentrations, the present theory predicts a significant nonlinear and weaker dependence on √c which is in very good agreement with experimental results. The present theory is self-contained and does not involve any adjustable parameter.

  6. Displacement separations by continuous annular chromatography

    SciTech Connect

    DeCarli, J.P. II; Carta, G. ); Byers, C.H. . Chemical Technology Div.)

    1988-01-01

    Continuous annular chromatography (CAC) has been introduced as an effective means of carrying out chromatographic separations in a truly continuous manner. Process applications have been demonstrated. In this work the authors demonstrate how CAC can be operated for displacement development separations. In this mode of operation of the apparatus separation and concentration of multicomponent mixtures can be obtained simultaneously and continuously. Experimental results and model simulations for this novel separation device are presented along with a comparison of different modes of operation and a discussion of industrial applications.

  7. Continuation of spiral waves

    NASA Astrophysics Data System (ADS)

    Bordyugov, Grigory; Engel, Harald

    2007-04-01

    We describe a new numerical method of computing rigidly rotating spiral waves, which is based on solving the Neumann boundary-value problem for the radius-dependent angular Fourier modes. Utilizing the established continuation engine AUTO, our method is simple in implementation and can be easily modified to suit a particular reaction-diffusion system. Since the method does not involve direct simulations of the reaction-diffusion system, unstable branches of rigidly rotating spiral waves can be computed as well. We illustrate our method by computing single- and multi-armed spirals in the Barkley model. Continuation of single-armed spirals displays nearly identical results with the Barkley’s continuation code STEADY. The dependence of spiral waves on the geometry of the medium reproduces the results of numerical simulations reported before in [A.M. Pertsov, E.A. Ermakova, A.V. Panfilov, Rotating spiral waves in a modified Fitz-Hugh-Nagumo model, Physica D 14 (1) (1984) 117-124], revealing, however, some subtle details like non-monotonous dependence of the rotation frequency on the disc radius and the existence of an unstable rotating solution that separates coexisting free and pinned spirals. We demonstrate that on bounded discs, spiral waves are accompanied by boundary spots - slowly rotating solutions which are localized near the outer boundary of the disc. Boundary spots are shown to be closely related to one- and two-dimensional unstable critical solutions, such as unstable pulses in one dimension and critical fingers in two dimensions, which separate spiral waves from shrinking wave segments.

  8. A la Mode II.

    ERIC Educational Resources Information Center

    Stowe, Richard A.

    This paper describes two modes of educational decision-making: Mode I, in which the instructor makes such decisions as what to teach, to whom, when, in what order, at what pace, and at what complexity level; and Mode II, in which the learner makes the decisions. While Mode I comprises most of what is regarded as formal education, the learner in…

  9. List mode multichannel analyzer

    DOEpatents

    Archer, Daniel E.; Luke, S. John; Mauger, G. Joseph; Riot, Vincent J.; Knapp, David A.

    2007-08-07

    A digital list mode multichannel analyzer (MCA) built around a programmable FPGA device for onboard data analysis and on-the-fly modification of system detection/operating parameters, and capable of collecting and processing data in very small time bins (<1 millisecond) when used in histogramming mode, or in list mode as a list mode MCA.

  10. Structural damage localization by outlier analysis of signal-processed mode shapes - Analytical and experimental validation

    NASA Astrophysics Data System (ADS)

    Ulriksen, M. D.; Damkilde, L.

    2016-02-01

    Contrary to global modal parameters such as eigenfrequencies, mode shapes inherently provide structural information on a local level. Therefore, this particular modal parameter and its derivatives are utilized extensively for damage identification. Typically, more or less advanced mathematical methods are employed to identify damage-induced discontinuities in the spatial mode shape signals, hereby, potentially, facilitating damage detection and/or localization. However, by being based on distinguishing damage-induced discontinuities from other signal irregularities, an intrinsic deficiency in these methods is the high sensitivity towards measurement noise. In the present paper, a damage localization method which, compared to the conventional mode shape-based methods, has greatly enhanced robustness towards measurement noise is proposed. The method is based on signal processing of a spatial mode shape by means of continuous wavelet transformation (CWT) and subsequent application of a generalized discrete Teager-Kaiser energy operator (GDTKEO) to identify damage-induced mode shape discontinuities. In order to evaluate whether the identified discontinuities are in fact damage-induced, outlier analysis is conducted by applying the Mahalanobis metric to major principal scores of the sensor-located bands of the signal-processed mode shape. The method is tested analytically and benchmarked with other mode shape-based damage localization approaches on the basis of a free-vibrating beam and validated experimentally in the context of a residential-sized wind turbine blade subjected to an impulse load.

  11. Thermal conductivity of supercooled water.

    PubMed

    Biddle, John W; Holten, Vincent; Sengers, Jan V; Anisimov, Mikhail A

    2013-04-01

    The heat capacity of supercooled water, measured down to -37°C, shows an anomalous increase as temperature decreases. The thermal diffusivity, i.e., the ratio of the thermal conductivity and the heat capacity per unit volume, shows a decrease. These anomalies may be associated with a hypothesized liquid-liquid critical point in supercooled water below the line of homogeneous nucleation. However, while the thermal conductivity is known to diverge at the vapor-liquid critical point due to critical density fluctuations, the thermal conductivity of supercooled water, calculated as the product of thermal diffusivity and heat capacity, does not show any sign of such an anomaly. We have used mode-coupling theory to investigate the possible effect of critical fluctuations on the thermal conductivity of supercooled water and found that indeed any critical thermal-conductivity enhancement would be too small to be measurable at experimentally accessible temperatures. Moreover, the behavior of thermal conductivity can be explained by the observed anomalies of the thermodynamic properties. In particular, we show that thermal conductivity should go through a minimum when temperature is decreased, as Kumar and Stanley observed in the TIP5P model of water. We discuss physical reasons for the striking difference between the behavior of thermal conductivity in water near the vapor-liquid and liquid-liquid critical points.

  12. Is failure mode and effect analysis reliable?

    PubMed

    Shebl, Nada Atef; Franklin, Bryony Dean; Barber, Nick

    2009-06-01

    To test the reliability of failure mode and effect analysis (FMEA) within a hospital setting in the United Kingdom. Two multidisciplinary groups were recruited, within 2 hospitals from the same National Health Services (NHS) Trust, to conduct separate FMEAs in parallel on the same topic. Each group conducted an FMEA for the use of vancomycin and gentamicin. The groups followed the basic FMEA steps, which included mapping the process of care; identifying potential failures within the process; determining the severity, probability, and detectability scores for these failures; and finally making recommendations to decrease these failures. Both groups described the process with 5 major steps: starting vancomycin or gentamicin, prescribing the antibiotics, administering the antibiotics, monitoring the antibiotics, and finally stopping or continuing the treatment. Although each group identified 50 failures, only 17 (17%) of them were common to both. Furthermore, the severity, detectability, and risk priority number scores for both groups differed markedly resulting in their failures being prioritized differently. Failure mode and effect analysis is a useful tool to aid multidisciplinary groups in understanding a process of care and identifying errors that may occur. However, the results of this study call into question the reliability of the FMEA process that was tested. The 2 groups identified similar steps in the process of care but different potential failures with very different risk priority numbers. Such discrepancies make it impossible to identify reliably those failures that should be prioritized and thus where money, time, and effort should be allocated to avoid these failures. Health care organizations should not solely depend on FMEA findings to improve patient safety.

  13. Sliding Mode Control of the X-33 Vehicle in Launch Mode

    NASA Technical Reports Server (NTRS)

    Shtessel, Yuri; Jackson, Mark; Hall, Charles; Krupp, Don; Hendrix, N. Douglas

    1998-01-01

    The "nested" structure of the control system for the X33 vehicle in launch mode is developed. Employing backstopping concepts, the outer loop (guidance) and the Inner loop (rates) continuous sliding mode controllers are designed. Simulations of the 3-DOF model of the X33 launch vehicle showed an accurate, robust, de-coupled tracking performance.

  14. Subcritical crack growth in soda-lime glass in combined mode I and mode II loading

    NASA Technical Reports Server (NTRS)

    Singh, Dileep; Shetty, Dinesh K.

    1990-01-01

    Subcritical crack growth under mixed-mode loading was studied in soda-lime glass. Pure mode I, combined mode I and mode II, and pure mode II loadings were achieved in precracked disk specimens by loading in diametral compression at selected angles with respect to the symmetric radial crack. Crack growth was monitored by measuring the resistance changes in a microcircuit grid consisting of parallel, electrically conducting grid lines deposited on the surface of the disk specimens by photolithography. Subcritical crack growth rates in pure mode I, pure mode II, and combined mode I and mode II loading could be described by an exponential relationship between crack growth rate and an effective crack driving force derived from a mode I-mode II fracture toughness envelope. The effective crack driving force was based on an empirical representation of the noncoplanar strain energy release rate. Stress intensities for kinked cracks were assessed using the method of caustics and an initial decrease and a subsequent increase in the subcritical crack growth rates of kinked cracks were shown to correlate with the variations of the mode I and the mode II stress intensities.

  15. Subcritical crack growth in soda-lime glass in combined mode I and mode II loading

    NASA Technical Reports Server (NTRS)

    Singh, Dileep; Shetty, Dinesh K.

    1990-01-01

    Subcritical crack growth under mixed-mode loading was studied in soda-lime glass. Pure mode I, combined mode I and mode II, and pure mode II loadings were achieved in precracked disk specimens by loading in diametral compression at selected angles with respect to the symmetric radial crack. Crack growth was monitored by measuring the resistance changes in a microcircuit grid consisting of parallel, electrically conducting grid lines deposited on the surface of the disk specimens by photolithography. Subcritical crack growth rates in pure mode I, pure mode II, and combined mode I and mode II loading could be described by an exponential relationship between crack growth rate and an effective crack driving force derived from a mode I-mode II fracture toughness envelope. The effective crack driving force was based on an empirical representation of the noncoplanar strain energy release rate. Stress intensities for kinked cracks were assessed using the method of caustics and an initial decrease and a subsequent increase in the subcritical crack growth rates of kinked cracks were shown to correlate with the variations of the mode I and the mode II stress intensities.

  16. Nanoporous Conducting Materials

    NASA Astrophysics Data System (ADS)

    Volosin, Alex

    Nanoporous electrically conducting materials can be prepared with high specific pore volumes and surface areas which make them well-suited for a wide variety of technologies including separation, catalysis and owing to their conductivity, energy related applications like solar cells, batteries and capacitors. General synthetic methods for nanoporous conducting materials that exhibit fine property control as well as facility and efficiency in their implementation continue to be highly sought after. Here, general methods for the synthesis of nanoporous conducting materials and their characterization are presented. Antimony-doped tin oxide (ATO), a transparent conducting oxide (TCO), and nanoporous conducting carbon can be prepared through the step-wise synthesis of interpenetrating inorganic/organic networks using well-established sol-gel methodology. The one-pot method produces an inorganic gel first that encompasses a solution of organic precursors. The surface of the inorganic gel subsequently catalyzes the formation of an organic gel network that interpenetrates throughout the inorganic gel network. These mutually supporting gel networks strengthen one another and allow for the use of evaporative drying methods and heat treatments that would usually destroy the porosity of an unsupported gel network. The composite gel is then selectively treated to either remove the organic network to provide a porous inorganic network, as is the case for antimony-doped tin oxide, or the inorganic network can be removed to generate a porous carbon material. The method exhibits flexibility in that the pore structure of the final porous material can be modified through the variation of the synthetic conditions. Additionally, porous carbons of hierarchical pore size distributions can be prepared by using wet alumina gel as a template dispersion medium and as a template itself. Alumina gels exhibit thixotropy, which is the ability of a solid to be sheared to a liquid state and upon

  17. Envelope Modes of Beams with Angular Momentum

    SciTech Connect

    Barnard, J J; Losic, B

    2000-08-21

    For a particle beam propagating in an alternating gradient focusing system, envelope equations are often employed to describe the evolution of the beam radii in the two directions transverse to the direction of propagation, and aligned with the principle axes of the alternating gradient system. When the beams have zero net angular momentum and when the alternating gradient focusing is approximated by a continuous focusing system, there are two normal modes to the envelope equations: the 'breathing' mode and a 'quadrupole' mode. In the former, the two radii oscillate in phase, and in the latter the radii oscillate 180 degrees out of phase. In this paper, we extend the analysis to include beams that have a finite angular momentum. We perturb the moment equations of ref. [1], wherein it was assumed that space charge is a distributed in a uniform density ellipse. Two additional modes are obtained. The breathing mode remains, but the quadrupole mode is split into two modes, and a new low frequency mode appears. We calculate the frequencies and eigenmodes of these four modes as a function of tune depression and a dimensionless net angular momentum. These modes can be excited by rotational errors of the quadrupoles in an alternating gradient focusing channel.

  18. Conductive dense hydrogen

    NASA Astrophysics Data System (ADS)

    Eremets, M.; Troyan, I.

    2012-12-01

    Hydrogen at ambient pressures and low temperatures forms a molecular crystal which is expected to display metallic properties under megabar pressures. This metal is predicted to be superconducting with a very high critical temperature Tc of 200-400 K. The superconductor may potentially be recovered metastably at ambient pressures, and it may acquire a new quantum state as a metallic superfluid and a superconducting superfluid. Recent experiments performed at low temperatures T < 100 K showed that at record pressures of 300 GPa, hydrogen remains in the molecular state and is an insulator with a band gap of appr 2 eV. Given our current experimental and theoretical understanding, hydrogen is expected to become metallic at pressures of 400-500 GPa, beyond the current limits of static pressures achievable using diamond anvil cells. We found that at room temperature and pressure > 220 GPa, new Raman modes arose, providing evidence for the transformation to a new opaque and electrically conductive phase IV. Above 260 GPa, in the next phase V, hydrogen reflected light well. Its resistance was nearly temperature-independent over a wide temperature range, down to 30 K, indicating that the hydrogen was metallic. Releasing the pressure induced the metallic phase to transform directly into molecular hydrogen with significant hysteresis at 200 GPa and 295 K. These data were published in our paper: M. I. Eremets and I. A. Troyan "Conductive dense hydrogen." Nature Materials 10: 927-931. We will present also new results on hydrogen: phase diagram with phases IV and V determined in P,T domain up to 300 GPa and 350 K. We will also discuss possible structures of phase IV based on our Raman and infrared measurements up to 300 GPa.

  19. Electrically conductive reticulated carbon composites

    SciTech Connect

    Sylwester, A.P.; Clough, R.L.

    1988-01-01

    This paper reports a new type of electrically conductive composite which offers advantageous properties and controlled processing. These new composites consist of a conductive open-celled, low-density, microcellular, carbonized foam filled with a nonconductive polymer or resin. The open-celled nature of the carbon foam provides a porous three-dimensional reticulated carbon structure. The large continuous-void volume can be readily filled with an insulating polymer or resin resulting in a three-dimensional conductive composite material. 9 refs., 3 figs.

  20. A stable snow-atmosphere coupled mode

    NASA Astrophysics Data System (ADS)

    Zhao, Liang; Zhu, Yuxiang; Liu, Haiwen; Liu, Zhongfang; Liu, Yanju; Li, Xiuping; Chen, Zhou

    2016-10-01

    Snow is both an important lower boundary forcing of the atmosphere and a response to atmospheric forcing in the extratropics. It is still unclear whether a stable snow-atmosphere coupled mode exists in the extratropics, like the ENSO in the tropics. Using Sliding Correlation analysis over Any Window, the present study quantitatively evaluates the stability of coupling relationships between the major modes of winter snow over the Northern Hemisphere and the winter atmospheric Arctic Oscillation (AO), the Antarctic Oscillation (AAO) and the Siberian High over the period 1872-2010, and discusses their possible relationships for different seasons. Results show that the first mode of the winter snow cover fraction and the winter AO together constitute a stable snow-atmosphere coupled mode, the SNAO. The coupled mode is stronger during recent decades than before. The snow anomaly over Europe is one key factor of the SNAO mode due to the high stability there, and the polar vortex anomaly in the atmosphere is its other key factor. The continuity of signals in the SNAO between autumn and winter is weaker than that between winter and spring. The second winter snow mode is generally stably correlated with the winter AAO and was more stable before the 1970s. The AAO signal with boreal snow has a strong continuity in seasonal transition. Generally, through these coupled modes, snow and atmosphere can interact in the same season or between different seasons: autumn snow can influence the winter atmosphere; the winter atmosphere can influence spring snow.

  1. Failure Mode/Mechanism Distributions

    DTIC Science & Technology

    1991-09-01

    Boards: Flashover (24996-000,NR) Broken NR Terminal Boards: Mechanical Breakage (24996-000,NR) Cortact Failure MR Terminals: (Intermittent contact... mechanism data on of various discrete semiconductor device types. The data has been compiled from reports of reliability demonstration tests conducted in...Room 3C0, Fnrbes Bu ilinn. Order No. FMD-91 Failure Mode/ Mechanism Distributions DTiC QUALIi INSPECTED 5 1991 Ace 94taa Yor SNTTS ai Prepared by: ,= t

  2. Thermal conductance of superlattice junctions

    SciTech Connect

    Lu, Simon; McGaughey, Alan J. H.

    2015-05-15

    We use molecular dynamics simulations and the lattice-based scattering boundary method to compute the thermal conductance of finite-length Lennard-Jones superlattice junctions confined by bulk crystalline leads. The superlattice junction thermal conductance depends on the properties of the leads. For junctions with a superlattice period of four atomic monolayers at temperatures between 5 and 20 K, those with mass-mismatched leads have a greater thermal conductance than those with mass-matched leads. We attribute this lead effect to interference between and the ballistic transport of emergent junction vibrational modes. The lead effect diminishes when the temperature is increased, when the superlattice period is increased, and when interfacial disorder is introduced, but is reversed in the harmonic limit.

  3. Recent Enhancements to the National Transonic Facility (Mixed Mode Operations)

    NASA Technical Reports Server (NTRS)

    Kilgore, W. Allen; Chan, David; Balakrishna, S.; Wahls, Richard A.

    2006-01-01

    The U.S. National Transonic Facility continues to make enhancements to provide quality data in a safe, efficient and cost effective method for aerodynamic ground testing. Recent enhancements discussed in this paper include the development of a Mixed-mode of operations that combine Air-mode operations with Nitrogen-mode operations. This implementation and operational results of this new Mixed-mode expands the ambient temperature transonic region of testing beyond the Air-mode limitations at a significantly reduced cost over Nitrogen Mode operation.

  4. State space analysis of boost DC/DC converter with voltage mode control

    NASA Astrophysics Data System (ADS)

    Shenoy, K. Latha; Nayak, C. Gurudas; Mandi, Rajashekar P.

    2017-07-01

    The boost converter belongs to the family of indirect energy transfer converters. The inductor stores energy during switch on and the output capacitor deliver power to the load. During switch off condition, the stored inductive energy appears in series with the input source and supply the output. The paper deals with the small signal analysis of dc-dc boost converter. It is used in modeling the closed loop converter parameters. The boost converter produces an undesirable Right-Half Plane Zero (RHPZ) in the small signal analysis due to which the implementation of voltage mode control needs attention. This requires compensating the regulator such that the crossover frequency occurs well below the frequency of the RHP zero. The paper describes modeling of voltage mode control boost converter operating in continuous conduction mode.

  5. Large mode radius resonators

    NASA Technical Reports Server (NTRS)

    Harris, Michael R.

    1987-01-01

    Resonator configurations permitting operation with large mode radius while maintaining good transverse mode discrimination are considered. Stable resonators incorporating an intracavity telescope and unstable resonator geometries utilizing an output coupler with a Gaussian reflectivity profile are shown to enable large radius single mode laser operation. Results of heterodyne studies of pulsed CO2 lasers with large (11mm e sup-2 radius) fundamental mode sizes are presented demonstrating minimal frequency sweeping in accordance with the theory of laser-induced medium perturbations.

  6. 7 CFR 1485.28 - Ethical conduct.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 10 2014-01-01 2014-01-01 false Ethical conduct. 1485.28 Section 1485.28 Agriculture Regulations of the Department of Agriculture (Continued) COMMODITY CREDIT CORPORATION, DEPARTMENT OF... COMMODITIES Market Access Program § 1485.28 Ethical conduct. (a) A MAP Participant shall conduct its business...

  7. 7 CFR 1485.28 - Ethical conduct.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 10 2013-01-01 2013-01-01 false Ethical conduct. 1485.28 Section 1485.28 Agriculture Regulations of the Department of Agriculture (Continued) COMMODITY CREDIT CORPORATION, DEPARTMENT OF... COMMODITIES Market Access Program § 1485.28 Ethical conduct. (a) A MAP Participant shall conduct its business...

  8. Few-mode fibers for mode division multiplexing transmission

    NASA Astrophysics Data System (ADS)

    Kubota, Hirokazu; Morioka, Toshio

    2012-01-01

    A study is presented of the fiber properties needed to achieve 10-mode multiplexing transmission. A combination of MIMO processing with optical LP mode separation is proposed to prevent the need for massive MIMO computation. The impact of mode crosstalk, differential mode delay, and the mode dependent loss of the few-mode fibers on mode multiplexing are discussed.

  9. Integrated mode converter for mode division multiplexing

    NASA Astrophysics Data System (ADS)

    Perez-Galacho, Diego; Alonso-Ramos, Carlos Alberto; Marris-Morini, Delphine; Vakarin, Vladyslav; Le Roux, Xavier; Ortega-Moñux, Alejandro; Wangüemert-Perez, Juan Gonzalo; Vivien, Laurent

    2016-05-01

    The ever growing demands of bandwidth in optical communication systems are making traditional Wavelength Division Multiplexing (WDM) based systems to reach its limit. In order to cope with future bandwidth demand is necessary to use new levels of orthogonality, such as the waveguide mode or the polarization state. Mode Division Multiplexing (MDM) has recently attracted attention as a possible solution to increase aggregate bandwidth. In this work we discuss the proposition a of mode converter that can cover the whole C-Band of optical communications. The Mode Converter is based on two Multimode Interference (MMI) couplers and a phase shifter. Insertion loss (IL) below 0.2 dB and Extinction ratio (ER) higher than 20 dB in a broad bandwidth range of 1.5 μm to 1.6 μm have been estimated. The total length of the device is less than 30 μm.

  10. Quasi-continuous magnets

    SciTech Connect

    Sims, J.R.; Naumovich, G.J.; Hoang, T.A.; Dent, P.C.

    1996-05-01

    The National High Magnetic Field Laboratory is completing a quasi-continuous magnet which will sustain a constant field of 60 T for 100 ms in a 32-mm 77 K bore. This magnet consists of 9 mechanically independent, nested, liquid nitrogen-cooled coils which are individually reinforced by high-strength stainless steel outer shells. The coils were wound from rectangular large cross-section, high-strength, high-conductivity copper conductor insulated wtih polyimide and fiberglass tapes. After winding, the coils were inserted into closely fitted, stainless steel reinforcing shells and impregnated with epoxy resin. Design, analysis, material, fabrication and operational issues for this class of magnets are reviewed. Fabrication and quality assurance testing of the 60 T coil set are covered in detail. Future growth of and possible links from this technology to other magnet systems are discussed. Needed improvements in design, analysis, materials, and fabrication are outlined.

  11. Compact Relativistic Magnetron with Output Mode Converter

    NASA Astrophysics Data System (ADS)

    Andreev, Andrey; Fuks, Mikhail; Schamiloglu, Edl

    2003-10-01

    We consider a relativistic magnetron in which all of the resonators of the anode block are smoothly continued onto a conical antenna up to the radius corresponding to the cutoff frequency of the radiated wave in a cylindrical waveguide. Such a magnetron is capable of high output power, is compact, has a high resistance to microwave breakdown, is able to work with extremely high currents, and has the possibility of forming desirable output radiation patterns. The magnetic field can be provided by a small solenoid over the resonant system, which is a much smaller volume than is required for the Helmholtz coils used in traditional relativistic magnetrons. The maximum size of this magnetron is the aperture of the horn antenna. The unique aspect of such a design is the possibility of using the horn antenna for conversion of the operating mode to lower order modes, including the TE_11 mode, which is radiated as a narrow wave beam. For a magnetron operating in π-mode, the mode converter comprises a continuation of the resonantor blocks onto the horn for those resonators that correspond to the symmetry of the output mode. For example, in order to provide Gaussian mode output only two diametrically opposite resonators of even-numbered resonators must be continued onto the horn. In this case the aperture of the horn antenna can be close to the cut-off diameter for the TE_11 mode, and the output power is limited only by breakdown of the output window. In this presentation results of preliminary calculations of the magnetron with output mode converters are presented.

  12. Competency Assessment and Continuing Education.

    ERIC Educational Resources Information Center

    Schlegel, John F.

    1978-01-01

    Described is the competency project being conducted by the American Association of Colleges of Pharmacy and the American Pharmaceutical Association, and its relationship to the development of continuing education programs. The project is attempting to specify standards of competency and develop self-assessment devices to be used by pharmacists.…

  13. Preparation of topological modes by Lyapunov control.

    PubMed

    Shi, Z C; Zhao, X L; Yi, X X

    2015-09-08

    By Lyapunov control, we present a proposal to drive quasi-particles into a topological mode in quantum systems described by a quadratic Hamiltonian. The merit of this control is the individual manipulations on the boundary sites. We take the Kitaev's chain as an illustration for Fermi systems and show that an arbitrary excitation mode can be steered into the Majorana zero mode by manipulating the chemical potential of the boundary sites. For Bose systems, taking the noninteracting Su-Schrieffer-Heeger (SSH) model as an example, we illustrate how to drive the system into the edge mode. The sensitivity of the fidelity to perturbations and uncertainties in the control fields and initial modes is also examined. The experimental feasibility of the proposal and the possibility to replace the continuous control field with square wave pulses is finally discussed.

  14. Preparation of topological modes by Lyapunov control

    PubMed Central

    Shi, Z. C.; Zhao, X. L.; Yi, X. X.

    2015-01-01

    By Lyapunov control, we present a proposal to drive quasi-particles into a topological mode in quantum systems described by a quadratic Hamiltonian. The merit of this control is the individual manipulations on the boundary sites. We take the Kitaev’s chain as an illustration for Fermi systems and show that an arbitrary excitation mode can be steered into the Majorana zero mode by manipulating the chemical potential of the boundary sites. For Bose systems, taking the noninteracting Su-Schrieffer-Heeger (SSH) model as an example, we illustrate how to drive the system into the edge mode. The sensitivity of the fidelity to perturbations and uncertainties in the control fields and initial modes is also examined. The experimental feasibility of the proposal and the possibility to replace the continuous control field with square wave pulses is finally discussed. PMID:26346317

  15. Single-mode and multimode Rayleigh--Taylor experiments on Nova

    SciTech Connect

    Remington, B.A.; Weber, S.V.; Marinak, M.M.; Haan, S.W.; Kilkenny, J.D.; Wallace, R.J.; Dimonte, G. )

    1995-01-01

    Rayleigh--Taylor (RT) experiments have been conducted with planar CH(Br) foils accelerated by x-ray ablation from a shaped, low adiabat drive. The surface perturbations investigated consisted of single-mode, two-mode, and eight-mode sinusoids. The perturbation evolution begins during the shock transit phase, when perturbations show gradual growth due to Richtmyer--Meshkov-like dynamics. After shock breakout, the compressed foils accelerate and perturbation growth continues due to the Rayleigh--Taylor instability. Detailed comparisons with simulations indicate that in the linear Rayleigh--Taylor regime, the single-mode perturbations grow exponentially in time. In the nonlinear regime, the growth slows and the perturbation shape changes from sinusoidal to bubble and spike'' with the appearance of higher Fourier harmonics. In the multimode perturbations, the individual modes grow independently in the linear regime, but become coupled in the nonlinear regime. In addition to the higher harmonics of the individual modes, coupling leads to the appearance of [ital k][sub [ital i

  16. AN EVALUATION OF PRIMARY DATA-COLLECTION MODES IN AN ADDRESS-BASED SAMPLING DESIGN.

    PubMed

    Amaya, Ashley; Leclere, Felicia; Carris, Kari; Liao, Youlian

    2015-01-01

    As address-based sampling becomes increasingly popular for multimode surveys, researchers continue to refine data-collection best practices. While much work has been conducted to improve efficiency within a given mode, additional research is needed on how multimode designs can be optimized across modes. Previous research has not evaluated the consequences of mode sequencing on multimode mail and phone surveys, nor has significant research been conducted to evaluate mode sequencing on a variety of indicators beyond response rates. We conducted an experiment within the Racial and Ethnic Approaches to Community Health across the U.S. Risk Factor Survey (REACH U.S.) to evaluate two multimode case-flow designs: (1) phone followed by mail (phone-first) and (2) mail followed by phone (mail-first). We compared response rates, cost, timeliness, and data quality to identify differences across case-flow design. Because surveys often differ on the rarity of the target population, we also examined whether changes in the eligibility rate altered the choice of optimal case flow. Our results suggested that, on most metrics, the mail-first design was superior to the phone-first design. Compared with phone-first, mail-first achieved a higher yield rate at a lower cost with equivalent data quality. While the phone-first design initially achieved more interviews compared to the mail-first design, over time the mail-first design surpassed it and obtained the greatest number of interviews.

  17. Modes of log gravity

    SciTech Connect

    Bergshoeff, Eric A.; Rosseel, Jan; Hohm, Olaf; Townsend, Paul K.

    2011-05-15

    The physical modes of a recently proposed D-dimensional 'critical gravity', linearized about its anti-de Sitter vacuum, are investigated. All 'log mode' solutions, which we categorize as 'spin-2' or 'Proca', arise as limits of the massive spin-2 modes of the noncritical theory. The linearized Einstein tensor of a spin-2 log mode is itself a 'nongauge' solution of the linearized Einstein equations whereas the linearized Einstein tensor of a Proca mode takes the form of a linearized general coordinate transformation. Our results suggest the existence of a holographically dual logarithmic conformal field theory.

  18. Mode stability of external cavity diode lasers.

    PubMed

    Saliba, Sebastian D; Junker, Mark; Turner, Lincoln D; Scholten, Robert E

    2009-12-10

    Mode stability is an important performance characteristic of external cavity diode lasers (ECDLs). It has been well established that the continuous mode-hop-free tuning range of a grating-feedback ECDL can be optimized by rotating the grating about a specific pivot location. We show that similar results can be obtained for other more convenient pivot locations by choosing instead the cavity length and grating location. The relative importance of the temperature stability of the diode and of the external cavity is also evaluated. We show that mechanically simple ECDL designs, using mostly standard components, can readily achieve a 35 GHz mode-hop-free tuning range at 780 nm.

  19. Streaming tearing mode

    NASA Technical Reports Server (NTRS)

    Shigeta, M.; Sato, T.; Dasgupta, B.

    1985-01-01

    The magnetohydrodynamic stability of streaming tearing mode is investigated numerically. A bulk plasma flow parallel to the antiparallel magnetic field lines and localized in the neutral sheet excites a streaming tearing mode more strongly than the usual tearing mode, particularly for the wavelength of the order of the neutral sheet width (or smaller), which is stable for the usual tearing mode. Interestingly, examination of the eigenfunctions of the velocity perturbation and the magnetic field perturbation indicates that the streaming tearing mode carries more energy in terms of the kinetic energy rather than the magnetic energy. This suggests that the streaming tearing mode instability can be a more feasible mechanism of plasma acceleration than the usual tearing mode instability.

  20. ToF-SIMS Depth Profiling Of Insulating Samples, Interlaced Mode Or Non-interlaced Mode?

    SciTech Connect

    Wang, Zhaoying; Jin, Ke; Zhang, Yanwen; Wang, Fuyi; Zhu, Zihua

    2014-11-01

    Dual beam depth profiling strategy has been widely adopted in ToF-SIMS depth profiling, in which two basic operation modes, interlaced mode and non-interlaced mode, are commonly used. Generally, interlaced mode is recommended for conductive or semi-conductive samples, whereas non-interlaced mode is recommended for insulating samples, where charge compensation can be an issue. Recent publications, however, show that the interlaced mode can be used effectively for glass depth profiling, despite the fact that glass is an insulator. In this study, we provide a simple guide for choosing between interlaced mode and non-interlaced mode for insulator depth profiling. Two representative cases are presented: (1) depth profiling of a leached glass sample, and (2) depth profiling of a single crystal MgO sample. In brief, the interlaced mode should be attempted first, because (1) it may provide reasonable-quality data, and (2) it is time-saving for most cases, and (3) it introduces low H/C/O background. If data quality is the top priority and measurement time is flexible, non-interlaced mode is recommended because interlaced mode may suffer from low signal intensity and poor mass resolution. A big challenge is tracking trace H/C/O in a highly insulating sample (e.g., MgO), because non-interlaced mode may introduce strong H/C/O background but interlaced mode may suffer from low signal intensity. Meanwhile, a C or Au coating is found to be very effective to improve the signal intensity. Surprisingly, the best analyzing location is not on the C or Au coating, but at the edge (outside) of the coating.

  1. Quenching rattling modes in skutterudites with pressure

    SciTech Connect

    Sergueev, I.; Glazyrin, Konstantin; Kantor, Innokenty; McGuire, Michael A.; Chumakov, A. I.; Klobes, B.; Sales, Brian C.; Hermann, Raphael P.

    2015-06-15

    In this paper, a high-pressure study of the lattice dynamics in the filled skutterudite Eu0.84Fe4Sb12 was carried out by means of x-ray powder diffraction and nuclear inelastic scattering. The anharmonicity of particular phonon modes was characterized by mode and element specific Grüneisen parameters. The large anharmonicity of the rattling optical mode that is hybridized with the acoustical phonons at ambient pressure is reduced at high pressure as the phonon modes decouple. Finally, this result suggests that anharmonic coupling between acoustic and optical phonon modes plays a central role in the reduced thermal conductivity.

  2. Single-Mode VCSELs

    NASA Astrophysics Data System (ADS)

    Larsson, Anders; Gustavsson, Johan S.

    The only active transverse mode in a truly single-mode VCSEL is the fundamental mode with a near Gaussian field distribution. A single-mode VCSEL produces a light beam of higher spectral purity, higher degree of coherence and lower divergence than a multimode VCSEL and the beam can be more precisely shaped and focused to a smaller spot. Such beam properties are required in many applications. In this chapter, after discussing applications of single-mode VCSELs, we introduce the basics of fields and modes in VCSELs and review designs implemented for single-mode emission from VCSELs in different materials and at different wavelengths. This includes VCSELs that are inherently single-mode as well as inherently multimode VCSELs where higher-order modes are suppressed by mode selective gain or loss. In each case we present the current state-of-the-art and discuss pros and cons. At the end, a specific example with experimental results is provided and, as a summary, the most promising designs based on current technologies are identified.

  3. Comment on 'Acoustic plasma modes'

    NASA Technical Reports Server (NTRS)

    Oliva, J.; Ashcroft, N. W.

    1984-01-01

    In a recent treatment of the T = 0 acoustic plasma modes of a two-component Fermi liquid with Coulomb forces, Appel and Overhauser conclude that there exist three generally damped longitudinal acoustic branches. It is observed that this conclusion results from an inapplicable analytic continuation in their solution of the transport equations. There is only one longitudinal acoustic branch, and, in fact, when applied to the standard one-component Fermi-liquid model, the method of Appel and Overhauser also leads to the incorrect conclusion that there exist two longitudinal acoustic branches.

  4. An automatic mode-locked system for passively mode-locked fiber laser

    NASA Astrophysics Data System (ADS)

    Li, Sha; Xu, Jun; Chen, Guoliang; Mei, Li; Yi, Bo

    2013-12-01

    This paper designs and implements one kind of automatic mode-locked system. It can adjust a passively mode-locked fiber laser to keep steady mode-locked states automatically. So the unsteadiness of traditional passively mode-locked fiber laser can be avoided. The system transforms optical signals into electrical pulse signals and sends them into MCU after processing. MCU calculates the frequency of the signals and judges the state of the output based on a quick judgment algorithm. A high-speed comparator is used to check the signals and the comparison voltage can be adjusted to improve the measuring accuracy. Then by controlling two polarization controllers at an angle of 45degrees to each other, MCU extrudes the optical fibers to change the polarization until it gets proper mode-locked output. So the system can continuously monitor the output signal and get it back to mode-locked states quickly and automatically. States of the system can be displayed on the LCD and PC. The parameters of the steady mode-locked states can be stored into an EEPROM so that the system will get into mode-locked states immediately next time. Actual experiments showed that, for a 6.238MHz passively mode-locked fiber lasers, the system can get into steady mode-locked states automatically in less than 90s after starting the system. The expected lock time can be reduced to less than 20s after follow up improvements.

  5. Adult and Continuing Education: Continuities and Discontinuities

    ERIC Educational Resources Information Center

    Tennant, Mark

    2005-01-01

    This paper presents a comprehensive review of the five-volume set, "Adult and Continuing Education." This publication is a monumental and diverse collection of material related directly or indirectly to the broad theme of adult and continuing education. The collection captures a great deal of the thought which has informed the…

  6. How to Conduct Store Observations of Tobacco Marketing and Products.

    PubMed

    Feld, Ashley L; Johnson, Trent O; Byerly, Katherine W; Ribisl, Kurt M

    2016-02-18

    As tobacco companies continue to heavily market their products at the point of sale, tobacco control groups seek strategies to combat the negative effects of this marketing. Store observations, which have been widely used by researchers and practitioners alike, are an excellent surveillance tool. This article provides a guide for public health practitioners interested in working in the tobacco retail environment by detailing the steps involved in conducting store observations of tobacco marketing and products including 1) obtaining tobacco product retailer lists, 2) creating measures, 3) selecting a mode of data collection, 4) training data collectors, and 5) analyzing data. We also highlight issues that may arise while in the field and provide information on disseminating results of store observations, including the potential policy implications.

  7. How to Conduct Store Observations of Tobacco Marketing and Products

    PubMed Central

    Feld, Ashley L.; Johnson, Trent O.; Byerly, Katherine W.

    2016-01-01

    As tobacco companies continue to heavily market their products at the point of sale, tobacco control groups seek strategies to combat the negative effects of this marketing. Store observations, which have been widely used by researchers and practitioners alike, are an excellent surveillance tool. This article provides a guide for public health practitioners interested in working in the tobacco retail environment by detailing the steps involved in conducting store observations of tobacco marketing and products including 1) obtaining tobacco product retailer lists, 2) creating measures, 3) selecting a mode of data collection, 4) training data collectors, and 5) analyzing data. We also highlight issues that may arise while in the field and provide information on disseminating results of store observations, including the potential policy implications. PMID:26890408

  8. 3-D Mixed Mode Delamination Fracture Criteria - An Experimentalist's Perspective

    NASA Technical Reports Server (NTRS)

    Reeder, James R.

    2006-01-01

    Many delamination failure criteria based on fracture toughness have been suggested over the past few decades, but most only covered the region containing mode I and mode II components of loading because that is where toughness data existed. With new analysis tools, more 3D analyses are being conducted that capture a mode III component of loading. This has increased the need for a fracture criterion that incorporates mode III loading. The introduction of a pure mode III fracture toughness test has also produced data on which to base a full 3D fracture criterion. In this paper, a new framework for visualizing 3D fracture criteria is introduced. The common 2D power law fracture criterion was evaluated to produce unexpected predictions with the introduction of mode III and did not perform well in the critical high mode I region. Another 2D criterion that has been shown to model a wide range of materials well was used as the basis for a new 3D criterion. The new criterion is based on assumptions that the relationship between mode I and mode III toughness is similar to the relation between mode I and mode II and that a linear interpolation can be used between mode II and mode III. Until mixed-mode data exists with a mode III component of loading, 3D fracture criteria cannot be properly evaluated, but these assumptions seem reasonable.

  9. Ordinary electromagnetic mode instability

    NASA Technical Reports Server (NTRS)

    Cheng, C. Z.

    1974-01-01

    The instability of the ordinary electromagnetic mode propagating perpendicular to an external magnetic field is studied for a single-species plasma with ring velocity distribution. The marginal instability boundaries for both the purely growing mode and the propagating growing modes are calculated from the instability criteria. The dispersion characteristics for various sets of plasma parameters are also given. The typical growth rates are of the order of the cyclotron frequency.

  10. Characterization of mode 1 and mixed-mode failure of adhesive bonds between composite adherends

    NASA Technical Reports Server (NTRS)

    Mall, S.; Johnson, W. S.

    1985-01-01

    A combined experimental and analytical investigation of an adhesively bonded composite joint was conducted to characterize both the static and fatigue beyond growth mechanism under mode 1 and mixed-mode 1 and 2 loadings. Two bonded systems were studied: graphite/epoxy adherends bonded with EC 3445 and FM-300 adhesives. For each bonded system, two specimen types were tested: a double-cantilever-beam specimen for mode 1 loading and a cracked-lapshear specimen for mixed-mode 1 and 2 loading. In all specimens tested, failure occurred in the form of debond growth. Debonding always occurred in a cohesive manner with EC 3445 adhesive. The FM-300 adhesive debonded in a cohesive manner under mixed-mode 1 and 2 loading, but in a cohesive, adhesive, or combined cohesive and adhesive manner under mode 1 loading. Total strain-energy release rate appeared to be the driving parameter for debond growth under static and fatigue loadings.

  11. Calibration-free electrical conductivity measurements for highly conductive slags

    SciTech Connect

    MACDONALD,CHRISTOPHER J.; GAO,HUANG; PAL,UDAY B.; VAN DEN AVYLE,JAMES A.; MELGAARD,DAVID K.

    2000-05-01

    This research involves the measurement of the electrical conductivity (K) for the ESR (electroslag remelting) slag (60 wt.% CaF{sub 2} - 20 wt.% CaO - 20 wt.% Al{sub 2}O{sub 3}) used in the decontamination of radioactive stainless steel. The electrical conductivity is measured with an improved high-accuracy-height-differential technique that requires no calibration. This method consists of making continuous AC impedance measurements over several successive depth increments of the coaxial cylindrical electrodes in the ESR slag. The electrical conductivity is then calculated from the slope of the plot of inverse impedance versus the depth of the electrodes in the slag. The improvements on the existing technique include an increased electrochemical cell geometry and the capability of measuring high precision depth increments and the associated impedances. These improvements allow this technique to be used for measuring the electrical conductivity of highly conductive slags such as the ESR slag. The volatilization rate and the volatile species of the ESR slag measured through thermogravimetric (TG) and mass spectroscopy analysis, respectively, reveal that the ESR slag composition essentially remains the same throughout the electrical conductivity experiments.

  12. Dual-Mode Combustor

    NASA Technical Reports Server (NTRS)

    Trefny, Charles J (Inventor); Dippold, Vance F (Inventor)

    2013-01-01

    A new dual-mode ramjet combustor used for operation over a wide flight Mach number range is described. Subsonic combustion mode is usable to lower flight Mach numbers than current dual-mode scramjets. High speed mode is characterized by supersonic combustion in a free-jet that traverses the subsonic combustion chamber to a variable nozzle throat. Although a variable combustor exit aperture is required, the need for fuel staging to accommodate the combustion process is eliminated. Local heating from shock-boundary-layer interactions on combustor walls is also eliminated.

  13. Asymmetric Bessel modes.

    PubMed

    Kotlyar, V V; Kovalev, A A; Soifer, V A

    2014-04-15

    We propose a new, three-parameter family of diffraction-free asymmetric elegant Bessel modes (aB-modes) with an integer and fractional orbital angular momentum (OAM). The aB-modes are described by the nth-order Bessel function of the first kind with complex argument. The asymmetry degree of the nonparaxial aB-mode is shown to depend on a real parameter c≥0: when c=0, the aB-mode is identical to a conventional radially symmetric Bessel mode; with increasing c, the aB-mode starts to acquire a crescent form, getting stretched along the vertical axis and shifted along the horizontal axis for c≫1. On the horizontal axis, the aB-modes have a denumerable number of isolated intensity zeros that generate optical vortices with a unit topological charge of opposite sign on opposite sides of 0. At different values of the parameter c, the intensity zeros change their location on the horizontal axis, thus changing the beam's OAM. An isolated intensity zero on the optical axis generates an optical vortex with topological charge n. The OAM per photon of an aB-mode depends near-linearly on c, being equal to ℏ(n+cI1(2c)/I0(2c)), where ℏ is the Planck constant and In(x) is a modified Bessel function.

  14. SAMPEX special pointing mode

    NASA Technical Reports Server (NTRS)

    Markley, F. Landis; Flatley, Thomas W.; Leoutsakos, Theodore

    1995-01-01

    A new pointing mode has been developed for the Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX) spacecraft. This pointing mode orients the instrument boresights perpendicular to the field lines of the Earth's magnetic field in regions of low field strength and parallel to the field lines in regions of high field strength, to allow better characterization of heavy ions trapped by the field. The new mode uses magnetometer signals and is algorithmically simpler than the previous control mode, but it requires increased momentum wheel activity. It was conceived, designed, tested, coded, uplinked to the spacecraft, and activated in less than seven months.

  15. Trapped modes in finite quantum waveguides

    NASA Astrophysics Data System (ADS)

    Delitsyn, A. L.; Nguyen, B. T.; Grebenkov, D. S.

    2012-06-01

    The eigenstates of an electron in an infinite quantum waveguide (e.g., a bent strip or a twisted tube) are often trapped or localized in a bounded region that prohibits the electron transmission through the waveguide at the corresponding energies. We revisit this statement for resonators with long but finite branches that we call "finite waveguides". Although the Laplace operator in bounded domains has no continuous spectrum and all eigenfunctions have finite L2 norm, the trapping of an eigenfunction can be understood as its exponential decay inside the branches. We describe a general variational formalism for detecting trapped modes in such resonators. For finite waveguides with general cylindrical branches, we obtain a sufficient condition which determines the minimal length of branches for getting a trapped eigenmode. Varying the branch lengths may switch certain eigenmodes from non-trapped to trapped or, equivalently, the waveguide state from conducting to insulating. These concepts are illustrated for several typical waveguides (L-shape, bent strip, crossing of two strips, etc.). We conclude that the well-established theory of trapping in infinite waveguides may be incomplete and require further development for applications to finite-size microscopic quantum devices.

  16. The mode switching of PSR B2020+28

    NASA Astrophysics Data System (ADS)

    Wen, Z. G.; Wang, N.; Yan, W. M.; Yuan, J. P.; Liu, Z. Y.; Chen, M. Z.; Chen, J. L.

    2016-08-01

    This paper reports on polarimetric radiation properties based on the switching modes of normal PSR B2020+28 by analyzing the data acquired from the Nanshan 25-m radio telescope at 1556 MHz. With nearly 8 hours quasi-continuous observation, the data presented some striking and updated phenomena. The change of relative intensity between the leading and trailing components is the predominant feature of mode switching. The intensity ratio between the leading and trailing components are measured for the individual profiles averaged over 30 seconds. It is found that there is an excess of high ratios over the normal distribution, which indicates that two modes exist in the pulsar. The distribution of abnormal mode has a narrower width indicating that the abnormal mode is more stable than the normal mode. A total of 76 mode switching events are detected in our data. It spends 89 % in the normal mode and 11 % in the abnormal mode. The intrinsic distributions of mode timescales are constrained with power-law distributions. The significant difference in the index of the duration distribution between normal and abnormal modes possibly indicates that the timescale for the abnormal mode to get stable is shorter than that for the normal mode. The frequent switching between both modes may indicate that the oscillations between different magnetospheric states are rapid.

  17. Continuities, Discontinuities, Interactions: Values, Education, and Neuroethics

    ERIC Educational Resources Information Center

    Semetsky, Inna

    2009-01-01

    This article begins by revisiting the current model of values education (moral education) which has recently been set up in Australian schools. This article problematizes the pedagogical model of teaching values in the direct transmission mode from the perspective of the continuity of experience as central to the philosophies of John Dewey and…

  18. Continuities, Discontinuities, Interactions: Values, Education, and Neuroethics

    ERIC Educational Resources Information Center

    Semetsky, Inna

    2009-01-01

    This article begins by revisiting the current model of values education (moral education) which has recently been set up in Australian schools. This article problematizes the pedagogical model of teaching values in the direct transmission mode from the perspective of the continuity of experience as central to the philosophies of John Dewey and…

  19. Operationalization of Strategic Change in Continuing Education

    ERIC Educational Resources Information Center

    Wong, Evia O. W.

    2005-01-01

    Purpose: Hong Kong continuing education has encountered vigorous change in recent years. It is not limited to the mode of teaching and learning. Changing government policies, fund cutting to the higher education system and the entry of overseas university degrees increase the intensity of competition in the environment to an extraordinary extent.…

  20. Continuing Education for R&D Careers.

    ERIC Educational Resources Information Center

    Social Research, Inc., Chicago, IL.

    This study collected and interpreted facts on the need for, use of, and appraisal of, professional continuing education (PCE) by research and development scientists and engineers in the Federal government and industry. There were three broad approaches: interaction modes (including professional meetings, seminars, lectures, and sabbatical leaves);…

  1. Operationalization of Strategic Change in Continuing Education

    ERIC Educational Resources Information Center

    Wong, Evia O. W.

    2005-01-01

    Purpose: Hong Kong continuing education has encountered vigorous change in recent years. It is not limited to the mode of teaching and learning. Changing government policies, fund cutting to the higher education system and the entry of overseas university degrees increase the intensity of competition in the environment to an extraordinary extent.…

  2. Conducting Compositions of Matter

    NASA Technical Reports Server (NTRS)

    Viswanathan, Tito (Inventor)

    1999-01-01

    The invention provides conductive compositions of matter, as well as methods for the preparation of the conductive compositions of matter, solutions comprising the conductive compositions of matter, and methods of preparing fibers or fabrics having improved anti-static properties employing the conductive compositions of matter.

  3. Conducting Compositions of Matter

    NASA Technical Reports Server (NTRS)

    Viswanathan, Tito (Inventor)

    2001-01-01

    The invention provides conductive compositions of matter, as well as methods for the preparation of the conductive compositions of matter, solutions comprising the conductive compositions of matter, and methods of preparing fibers or fabrics having improved anti-static properties employing the conductive compositions of matter.

  4. Conducting compositions of matter

    NASA Technical Reports Server (NTRS)

    Viswanathan, Tito (Inventor)

    2000-01-01

    The invention provides conductive compositions of matter, as well as methods for the preparation of the conductive compositions of matter, solutions comprising the conductive compositions of matter, and methods of preparing fibers or fabrics having improved anti-static properties employing the conductive compositions of matter.

  5. Polyaniline Based Conductive Textiles

    NASA Astrophysics Data System (ADS)

    Teli, M.; Dash, S.; Desai, P.

    2014-12-01

    The conductive polymers were mixed with binder and coated on cotton, polyester and wool fabric, keeping conductive polymer concentration at 5 %. Conductive woven fabrics were obtained by pad-dry-cure coating technique. The surface and bulk conductivity behaviour of the coating paste with respect to temperature were studied using four probe and two probe technique. The conductivity studies show that the coated fabrics have good electrical conductivity in the range of 33.2 μS/cm-3281 μS/cm and there was an increase in conductivity with rise in temperature.

  6. Default mode network in the effects of Δ9-Tetrahydrocannabinol (THC) on human executive function.

    PubMed

    Bossong, Matthijs G; Jansma, J Martijn; van Hell, Hendrika H; Jager, Gerry; Kahn, René S; Ramsey, Nick F

    2013-01-01

    Evidence is increasing for involvement of the endocannabinoid system in cognitive functions including attention and executive function, as well as in psychiatric disorders characterized by cognitive deficits, such as schizophrenia. Executive function appears to be associated with both modulation of active networks and inhibition of activity in the default mode network. In the present study, we examined the role of the endocannabinoid system in executive function, focusing on both the associated brain network and the default mode network. A pharmacological functional magnetic resonance imaging (fMRI) study was conducted with a placebo-controlled, cross-over design, investigating effects of the endocannabinoid agonist Δ9-tetrahydrocannabinol (THC) on executive function in 20 healthy volunteers, using a continuous performance task with identical pairs. Task performance was impaired after THC administration, reflected in both an increase in false alarms and a reduction in detected targets. This was associated with reduced deactivation in a set of brain regions linked to the default mode network, including posterior cingulate cortex and angular gyrus. Less deactivation was significantly correlated with lower performance after THC. Regions that were activated by the continuous performance task, notably bilateral prefrontal and parietal cortex, did not show effects of THC. These findings suggest an important role for the endocannabinoid system in both default mode modulation and executive function. This may be relevant for psychiatric disorders associated with executive function deficits, such as schizophrenia and ADHD.

  7. Mode pumping experiments on biomolecules

    SciTech Connect

    Austin, R.H.; Erramilli, S.; Xie, A.; Schramm, A.

    1995-12-31

    We will explore several aspects of protein dynamics and energy transfer that can be explored by using the intense, picosecond, tunable mid-IR output of the FEL. In order of appearance they are: (1) Saturation recovery and inter-level coupling of the low temperature amide-I band in acetanilide. This is a continuation of earlier experiments to test soliton models in crystalline hydrogen bonded solids. In this experiment we utilize the sub-picosecond time resolution and low repetition rate of the Stanford SCLA FEL to do both T{sub 1} and T{sub 2} relaxation measurements at 1650 cm{sup -1}. (2) Probing the influence of collective dynamics in sensory rhodopsin. In this experiment we use the FIR output of the Stanford FIREFLY FEL to determine the lifetime of collective modes in the photo-active protein sensory rhodopsin, and begin experiments on the influence of collective modes on retinal reaction dynamics. (3) Probing the transition states of enzymes. This experiment, in the initial stages, attempts to use the intense IR output of the FEL to probe and influence the reaction path of a transition state analog for the protein nucleoside hydrolase. The transition state of the inosine substrate is believed to have critical modes softened by the protein so that bond-breaking paths show absorption at approximately 800 cm{sup -1}. A form of action spectrum using FEL excitation will be used to probe this state.

  8. Solid-state fermentation: a continuous process for fungal tannase production.

    PubMed

    van de Lagemaat, J; Pyle, D L

    2004-09-30

    Truly continuous solid-state fermentations with operating times of 2-3 weeks were conducted in a prototype bioreactor for the production of fungal (Penicillium glabrum) tannase from a tannin-containing model substrate. Substantial quantities of the enzyme were synthesized throughout the operating periods and (imperfect) steady-state conditions seemed to be achieved soon after start-up of the fermentations. This demonstrated for the first time the possibility of conducting solid-state fermentations in the continuous mode and with a constant noninoculated feed. The operating variables and fermentation conditions in the bioreactor were sufficiently well predicted for the basic reinoculation concept to succeed. However, an incomplete understanding of the microbial mechanisms, the experimental system, and their interaction indicated the need for more research in this novel area of solid-state fermentation.

  9. Guidelines for Conducting an Ethnic Heritage Search.

    ERIC Educational Resources Information Center

    Williams, Maxine Patrick

    Based on the work of a 22-member research team in the San Diego Community College District, this booklet offers guidelines for developing cultural awareness and presents instruments for conducting an ethnic heritage search, i.e., a systematic examination of a culture to, for example, reveal reasons for customs or practices or clarify the modes of…

  10. Highly elastic conductive polymeric MEMS

    PubMed Central

    Ruhhammer, J; Zens, M; Goldschmidtboeing, F; Seifert, A; Woias, P

    2015-01-01

    Polymeric structures with integrated, functional microelectrical mechanical systems (MEMS) elements are increasingly important in various applications such as biomedical systems or wearable smart devices. These applications require highly flexible and elastic polymers with good conductivity, which can be embedded into a matrix that undergoes large deformations. Conductive polydimethylsiloxane (PDMS) is a suitable candidate but is still challenging to fabricate. Conductivity is achieved by filling a nonconductive PDMS matrix with conductive particles. In this work, we present an approach that uses new mixing techniques to fabricate conductive PDMS with different fillers such as carbon black, silver particles, and multiwalled carbon nanotubes. Additionally, the electrical properties of all three composites are examined under continuous mechanical stress. Furthermore, we present a novel, low-cost, simple three-step molding process that transfers a micro patterned silicon master into a polystyrene (PS) polytetrafluoroethylene (PTFE) replica with improved release features. This PS/PTFE mold is used for subsequent structuring of conductive PDMS with high accuracy. The non sticking characteristics enable the fabrication of delicate structures using a very soft PDMS, which is usually hard to release from conventional molds. Moreover, the process can also be applied to polyurethanes and various other material combinations. PMID:27877753

  11. Highly elastic conductive polymeric MEMS

    NASA Astrophysics Data System (ADS)

    Ruhhammer, J.; Zens, M.; Goldschmidtboeing, F.; Seifert, A.; Woias, P.

    2015-02-01

    Polymeric structures with integrated, functional microelectrical mechanical systems (MEMS) elements are increasingly important in various applications such as biomedical systems or wearable smart devices. These applications require highly flexible and elastic polymers with good conductivity, which can be embedded into a matrix that undergoes large deformations. Conductive polydimethylsiloxane (PDMS) is a suitable candidate but is still challenging to fabricate. Conductivity is achieved by filling a nonconductive PDMS matrix with conductive particles. In this work, we present an approach that uses new mixing techniques to fabricate conductive PDMS with different fillers such as carbon black, silver particles, and multiwalled carbon nanotubes. Additionally, the electrical properties of all three composites are examined under continuous mechanical stress. Furthermore, we present a novel, low-cost, simple three-step molding process that transfers a micro patterned silicon master into a polystyrene (PS) polytetrafluoroethylene (PTFE) replica with improved release features. This PS/PTFE mold is used for subsequent structuring of conductive PDMS with high accuracy. The non sticking characteristics enable the fabrication of delicate structures using a very soft PDMS, which is usually hard to release from conventional molds. Moreover, the process can also be applied to polyurethanes and various other material combinations.

  12. Modes of Production: Fordism and Distance Education.

    ERIC Educational Resources Information Center

    Farnes, Nick

    1993-01-01

    Analyzes the historical development of economic and educational systems and considers the relationship between industrialization and distance education. Modes of production and stages of conventional and distance education development are described, and future possibilities of mass higher and continuing education through the use of computer-based…

  13. Tearing Modes in Tokamaks

    SciTech Connect

    White, R. B.

    2008-05-14

    This lecture gives a basic introduction to magnetic pound elds, magnetic surface destruction, toroidal equilibrium and tearing modes in a tokamak, including the linear and nonlinear development of these modes and their modi pound cation by current drive and bootstrap current, and sawtooth oscillations and disruptions.

  14. Thermal conductance of graphene/hexagonal boron nitride heterostructures

    NASA Astrophysics Data System (ADS)

    Lu, Simon; McGaughey, Alan J. H.

    2017-03-01

    The lattice-based scattering boundary method is applied to compute the phonon mode-resolved transmission coefficients and thermal conductances of in-plane heterostructures built from graphene and hexagonal boron nitride (hBN). The thermal conductance of all structures is dominated by acoustic phonon modes near the Brillouin zone center that have high group velocity, population, and transmission coefficient. Out-of-plane modes make their most significant contributions at low frequencies, whereas in-plane modes contribute across the frequency spectrum. Finite-length superlattice junctions between graphene and hBN leads have a lower thermal conductance than comparable junctions between two graphene leads due to lack of transmission in the hBN phonon bandgap. The thermal conductances of bilayer systems differ by less than 10% from their single-layer counterparts on a per area basis, in contrast to the strong thermal conductivity reduction when moving from single- to multi-layer graphene.

  15. Mode decomposition evolution equations

    PubMed Central

    Wang, Yang; Wei, Guo-Wei; Yang, Siyang

    2011-01-01

    Partial differential equation (PDE) based methods have become some of the most powerful tools for exploring the fundamental problems in signal processing, image processing, computer vision, machine vision and artificial intelligence in the past two decades. The advantages of PDE based approaches are that they can be made fully automatic, robust for the analysis of images, videos and high dimensional data. A fundamental question is whether one can use PDEs to perform all the basic tasks in the image processing. If one can devise PDEs to perform full-scale mode decomposition for signals and images, the modes thus generated would be very useful for secondary processing to meet the needs in various types of signal and image processing. Despite of great progress in PDE based image analysis in the past two decades, the basic roles of PDEs in image/signal analysis are only limited to PDE based low-pass filters, and their applications to noise removal, edge detection, segmentation, etc. At present, it is not clear how to construct PDE based methods for full-scale mode decomposition. The above-mentioned limitation of most current PDE based image/signal processing methods is addressed in the proposed work, in which we introduce a family of mode decomposition evolution equations (MoDEEs) for a vast variety of applications. The MoDEEs are constructed as an extension of a PDE based high-pass filter (Europhys. Lett., 59(6): 814, 2002) by using arbitrarily high order PDE based low-pass filters introduced by Wei (IEEE Signal Process. Lett., 6(7): 165, 1999). The use of arbitrarily high order PDEs is essential to the frequency localization in the mode decomposition. Similar to the wavelet transform, the present MoDEEs have a controllable time-frequency localization and allow a perfect reconstruction of the original function. Therefore, the MoDEE operation is also called a PDE transform. However, modes generated from the present approach are in the spatial or time domain and can be

  16. Mode decomposition evolution equations.

    PubMed

    Wang, Yang; Wei, Guo-Wei; Yang, Siyang

    2012-03-01

    Partial differential equation (PDE) based methods have become some of the most powerful tools for exploring the fundamental problems in signal processing, image processing, computer vision, machine vision and artificial intelligence in the past two decades. The advantages of PDE based approaches are that they can be made fully automatic, robust for the analysis of images, videos and high dimensional data. A fundamental question is whether one can use PDEs to perform all the basic tasks in the image processing. If one can devise PDEs to perform full-scale mode decomposition for signals and images, the modes thus generated would be very useful for secondary processing to meet the needs in various types of signal and image processing. Despite of great progress in PDE based image analysis in the past two decades, the basic roles of PDEs in image/signal analysis are only limited to PDE based low-pass filters, and their applications to noise removal, edge detection, segmentation, etc. At present, it is not clear how to construct PDE based methods for full-scale mode decomposition. The above-mentioned limitation of most current PDE based image/signal processing methods is addressed in the proposed work, in which we introduce a family of mode decomposition evolution equations (MoDEEs) for a vast variety of applications. The MoDEEs are constructed as an extension of a PDE based high-pass filter (Europhys. Lett., 59(6): 814, 2002) by using arbitrarily high order PDE based low-pass filters introduced by Wei (IEEE Signal Process. Lett., 6(7): 165, 1999). The use of arbitrarily high order PDEs is essential to the frequency localization in the mode decomposition. Similar to the wavelet transform, the present MoDEEs have a controllable time-frequency localization and allow a perfect reconstruction of the original function. Therefore, the MoDEE operation is also called a PDE transform. However, modes generated from the present approach are in the spatial or time domain and can be

  17. Defining and Measuring Interpersonal Continuity of Care

    PubMed Central

    Saultz, John W.

    2003-01-01

    BACKGROUND In an effort to learn more about the importance of continuity of care to physicians and patients, I reviewed the medical literature on continuity of care to define interpersonal continuity and describe how it has been measured and studied. METHODS A search of the MEDLINE database from 1966 through April 2002 was conducted to find articles focusing on the keyword “continuity of patient care,” including all subheadings. Titles and abstracts of the resulting articles were screened to select articles focusing on interpersonal continuity in the physician-patient relationship or on the definition of continuity of care. These articles were systematically reviewed and analyzed for study method, measurement technique, and research theme. RESULTS A total of 379 original articles were found that addressed any aspect of continuity as an attribute of general medical care. One hundred forty-two articles directly related to the definition of continuity or to the concept of interpersonal continuity in the physician-patient relationship. Although the available literature reflects little agreement on how to define continuity of care, it is best defined as a hierarchy of 3 dimensions; informational, longitudinal, and interpersonal continuity. Interpersonal continuity is of particular interest for primary care. Twenty-one measurement techniques have been defined to study continuity, many of which relate to visit patterns and concentration rather than the interpersonal nature of the continuity relationship. CONCLUSIONS Future inquiry in family medicine should focus on better understanding the interpersonal dimension of continuity of care. PMID:15043374

  18. Zero-mode waveguides

    DOEpatents

    Levene, Michael J.; Korlach, Jonas; Turner, Stephen W.; Craighead, Harold G.; Webb, Watt W.

    2007-02-20

    The present invention is directed to a method and an apparatus for analysis of an analyte. The method involves providing a zero-mode waveguide which includes a cladding surrounding a core where the cladding is configured to preclude propagation of electromagnetic energy of a frequency less than a cutoff frequency longitudinally through the core of the zero-mode waveguide. The analyte is positioned in the core of the zero-mode waveguide and is then subjected, in the core of the zero-mode waveguide, to activating electromagnetic radiation of a frequency less than the cut-off frequency under conditions effective to permit analysis of the analyte in an effective observation volume which is more compact than if the analysis were carried out in the absence of the zero-mode waveguide.

  19. Excursions through KK modes

    SciTech Connect

    Furuuchi, Kazuyuki

    2016-07-07

    In this article we study Kaluza-Klein (KK) dimensional reduction of massive Abelian gauge theories with charged matter fields on a circle. Since local gauge transformations change position dependence of the charged fields, the decomposition of the charged matter fields into KK modes is gauge dependent. While whole KK mass spectrum is independent of the gauge choice, the mode number depends on the gauge. The masses of the KK modes also depend on the field value of the zero-mode of the extra dimensional component of the gauge field. In particular, one of the KK modes in the KK tower of each massless 5D charged field becomes massless at particular values of the extra-dimensional component of the gauge field. When the extra-dimensional component of the gauge field is identified with the inflaton, this structure leads to recursive cosmological particle productions.

  20. Excursions through KK modes

    NASA Astrophysics Data System (ADS)

    Furuuchi, Kazuyuki

    2016-07-01

    In this article we study Kaluza-Klein (KK) dimensional reduction of massive Abelian gauge theories with charged matter fields on a circle. Since local gauge transformations change position dependence of the charged fields, the decomposition of the charged matter fields into KK modes is gauge dependent. While whole KK mass spectrum is independent of the gauge choice, the mode number depends on the gauge. The masses of the KK modes also depend on the field value of the zero-mode of the extra dimensional component of the gauge field. In particular, one of the KK modes in the KK tower of each massless 5D charged field becomes massless at particular values of the extra-dimensional component of the gauge field. When the extra-dimensional component of the gauge field is identified with the inflaton, this structure leads to recursive cosmological particle productions.

  1. Low-threshold, dual-passive mode locking of a large mode area Nd:GdVO(4) laser.

    PubMed

    Schieffer, S L; Brajkovic, D; Cornea, A I; Schroeder, W A

    2006-07-24

    The all solid-state combination of a saturable Bragg mirror for amplitude modulation and a cascaded chi((2)):chi((2)) nonlinearity (phase-mismatched second harmonic crystal) as an axial-mode phase locker for continuous-wave mode locking of large mode area lasers is investigated. The dual-passive mode-locking technique generates extremely stable sub-10ps sech(2) pulses at 76MHz from a ~6W, TEM(00)-mode, diode-pumped, thermal-lens-shaped, Brewster Nd:GdVO(4) laser.

  2. Gate sequence for continuous variable one-way quantum computation

    PubMed Central

    Su, Xiaolong; Hao, Shuhong; Deng, Xiaowei; Ma, Lingyu; Wang, Meihong; Jia, Xiaojun; Xie, Changde; Peng, Kunchi

    2013-01-01

    Measurement-based one-way quantum computation using cluster states as resources provides an efficient model to perform computation and information processing of quantum codes. Arbitrary Gaussian quantum computation can be implemented sufficiently by long single-mode and two-mode gate sequences. However, continuous variable gate sequences have not been realized so far due to an absence of cluster states larger than four submodes. Here we present the first continuous variable gate sequence consisting of a single-mode squeezing gate and a two-mode controlled-phase gate based on a six-mode cluster state. The quantum property of this gate sequence is confirmed by the fidelities and the quantum entanglement of two output modes, which depend on both the squeezing and controlled-phase gates. The experiment demonstrates the feasibility of implementing Gaussian quantum computation by means of accessible gate sequences.

  3. Comparing the Discrete and Continuous Logistic Models

    ERIC Educational Resources Information Center

    Gordon, Sheldon P.

    2008-01-01

    The solutions of the discrete logistic growth model based on a difference equation and the continuous logistic growth model based on a differential equation are compared and contrasted. The investigation is conducted using a dynamic interactive spreadsheet. (Contains 5 figures.)

  4. Comparing the Discrete and Continuous Logistic Models

    ERIC Educational Resources Information Center

    Gordon, Sheldon P.

    2008-01-01

    The solutions of the discrete logistic growth model based on a difference equation and the continuous logistic growth model based on a differential equation are compared and contrasted. The investigation is conducted using a dynamic interactive spreadsheet. (Contains 5 figures.)

  5. Analytical performance characteristics of nanoelectrospray emitters as a function of conductive coating.

    PubMed

    Smith, Douglas R; Moy, Marie A; Dolan, Anthony R; Wood, Troy D

    2006-04-01

    As miniaturization of electrospray continues to become more prevalent in the mass spectrometry arsenal, numerous types of conductive coatings have been developed with miniaturized electrospray emitters. Different conductive coatings have different properties that may lead to differences in analytical performance. This paper investigates and compares the analytical properties of a series of applied conductive coatings for low-flow electrospray ionization developed in this laboratory vs. commercially-available types. Evaporated graphite is thoroughly compared with commercially available polyaniline (PANI) coated emitters and metal coated emitters. Each set of emitters was investigated to determine various performance characteristics, including susceptibility to electrical discharge in both positive and negative ionization modes, as well as emitter reproducibility and generation of a standard curve to determine each emitter coating's limit of detection and limit of quantitation. Furthermore, evaporated graphite and polyaniline coated fused silica capillaries were investigated to determine which coating is more stable over long-term analyses and during electrical discharge.

  6. Coupled conduction-convection problem for an underground rectangular duct containing three insulated cables

    SciTech Connect

    Liu, Y.; Phan-Thien, N.; Kemp, R.; Luo, X.L.

    1997-03-01

    The coupled heat conduction-convection problem for three insulating cables resting in a rectangular duct filled with air, which is buried underground, is solved by an operator-splitting pseudo-time-stepping finite element method. The method automatically satisfies the continuity of the interfacial temperature and heat flux. The temperature distribution in the metal cores, in the insulating layers, and in the surrounding air and soil, together with the convective flow pattern, are obtained simultaneously. From the profile of the local Nusselt number, which is strongly dependent on the thermal conductivity ratios and weakly dependent on the Rayleigh number, it is concluded that most of the heat transfer takes place via the bottom of the enclosure through a conductive mode.

  7. Keeping Communication Continuous

    NASA Technical Reports Server (NTRS)

    2003-01-01

    General Dynamics Decision Systems employees have played a role in supplying telemetry, tracking, and control (TT&C) and other communications systems to NASA and the U.S. Department of Defense for over 40 years. Providing integrated communication systems and subsystems for nearly all manned and unmanned U.S. space flights, the heritage of this Scottsdale, Arizona-based company includes S-band transceivers that enabled millions of Americans to see Neil Armstrong and hear his prophetic words from the Moon in 1969. More recently, Decision Systems has collaborated with NASA s Goddard Space Flight Center to develop transponders, wireless communications devices that pick up and automatically respond to an incoming signal, for NASA s Tracking and Data Relay Satellite System (TDRSS). Four generations of Decision Systems TDRSS transponders have been developed under Goddard s sponsorship. The company s Fourth Generation TDRSS User Transponder (TDRSS IV) allows low-Earth-orbiting spacecraft to communicate continuously with a single ground station at White Sands, New Mexico, through a constellation of geostationary relay satellites positioned at key locations around the Earth. In addition to the communications of forward link control commands and return link telemetry data, the TDRSS IV also supports spacecraft orbit tracking through coherent turn-around of a pseudo-noise ranging code and two-way Doppler tracking.When the NSBF adopted the use of global positioning system receivers for balloon position tracking, Decision Systems concluded that a simpler, noncoherent transceiver could provide the NSBF with the necessary TDRSS communications without the additional cost and complexity of a coherent transponder. The solution was to take the core design of the TDRSS IV Transponder, but remove the extra functionality that supported coherent turn-around. This would simplify the production effort, reduce the testing required, and result in a lower cost product with smaller size, weight

  8. 47 CFR 97.511 - Examinee conduct.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Examinee conduct. 97.511 Section 97.511 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES AMATEUR RADIO SERVICE Qualifying Examination Systems § 97.511 Examinee conduct. Each examinee must comply with the...

  9. 47 CFR 97.511 - Examinee conduct.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false Examinee conduct. 97.511 Section 97.511 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES AMATEUR RADIO SERVICE Qualifying Examination Systems § 97.511 Examinee conduct. Each examinee must comply with the...

  10. 47 CFR 97.511 - Examinee conduct.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Examinee conduct. 97.511 Section 97.511 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES AMATEUR RADIO SERVICE Qualifying Examination Systems § 97.511 Examinee conduct. Each examinee must comply with the...

  11. 47 CFR 97.511 - Examinee conduct.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false Examinee conduct. 97.511 Section 97.511 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES AMATEUR RADIO SERVICE Qualifying Examination Systems § 97.511 Examinee conduct. Each examinee must comply with the...

  12. 47 CFR 97.511 - Examinee conduct.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Examinee conduct. 97.511 Section 97.511 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES AMATEUR RADIO SERVICE Qualifying Examination Systems § 97.511 Examinee conduct. Each examinee must comply with the...

  13. The Conductivity of Solutions.

    ERIC Educational Resources Information Center

    Rayner-Canham, Geoff

    1993-01-01

    Presents historical background and modern explanations for the popular demonstration of showing conductivity of solutions through the insertion of a light-bulb conductivity tester into deionized water and water with salt in it. (PR)

  14. The Conductivity of Solutions.

    ERIC Educational Resources Information Center

    Rayner-Canham, Geoff

    1993-01-01

    Presents historical background and modern explanations for the popular demonstration of showing conductivity of solutions through the insertion of a light-bulb conductivity tester into deionized water and water with salt in it. (PR)

  15. Design principles of interfacial thermal conductance

    NASA Astrophysics Data System (ADS)

    Polanco, Carlos; Rastgarkafshgarkolaei, Rouzbeh; Zhang, Jingjie; Le, Nam; Norris, Pamela; Ghosh, Avik

    We explore fundamental principles to design the thermal conductance across solid interfaces by changing the composition and disorder of an intermediate matching layer. In absence of phonon-phonon interactions, the layer addition involves two competing effects that influence the conductance. The layer can act as an impedance matching 'bridge' to increase the mode-averaged phonon transmission. However, it also reduces the relevant modes that conserve their momenta transverse to the interface, so that the net result depends on features such as the overlap of conserving modes and the dispersivity of the transverse subbands. Moving into the interacting anharmonic regime, we find that the added layer aids conductance when the decreased resistances at the contact-layer boundaries compensate for the layer resistance. In fact, we show that the maximum conductance corresponds to an exact matching of the two separate contact-layer resistances. For instance, if we vary just the atomic mass across layers, then maximum conductance happens when the intervening layer mass is the geometric mean of the contact masses. We conjecture that the best interfacial layer is one that is compositionally graded into many geometric means - in other words, an exponential variation in thermal impedance.

  16. Dispersion and decay of collective modes in neutron star cores

    NASA Astrophysics Data System (ADS)

    Kobyakov, D. N.; Pethick, C. J.; Reddy, S.; Schwenk, A.

    2017-08-01

    We calculate the frequencies of collective modes of neutrons, protons, and electrons in the outer core of neutron stars. The neutrons and protons are treated in a hydrodynamic approximation and the electrons are regarded as collisionless. The coupling of the nucleons to the electrons leads to Landau damping of the collective modes and to significant dispersion of the low-lying modes. We investigate the sensitivity of the mode frequencies to the strength of entrainment between neutrons and protons, which is not well characterized. The contribution of collective modes to the thermal conductivity is evaluated.

  17. Programmes in Continuing Education

    ERIC Educational Resources Information Center

    Shah, L. R.

    1976-01-01

    The various types and forms of credit and non-credit university continuing education programmes are described in these extracts from a paper presented at the Hyderabad conference on university continuing education. (ABM)

  18. Surface Conductive Glass.

    ERIC Educational Resources Information Center

    Tanaka, John; Suib, Steven L.

    1984-01-01

    Discusses the properties of surface-conducting glass and the chemical nature of surface-conducting stannic (tin) oxide. Also provides the procedures necessary for the preparation of surface-conducting stannic oxide films on glass substrates. The experiment is suitable for the advanced inorganic chemistry laboratory. (JN)

  19. Conductance and Kondo Interference beyond Proportional Coupling

    NASA Astrophysics Data System (ADS)

    Dias da Silva, Luis G. G. V.; Lewenkopf, Caio H.; Vernek, Edson; Ferreira, Gerson J.; Ulloa, Sergio E.

    2017-09-01

    The transport properties of nanostructured systems are deeply affected by the geometry of the effective connections to metallic leads. In this work we derive a conductance expression for a class of interacting systems whose connectivity geometries do not meet the Meir-Wingreen proportional coupling condition. As an interesting application, we consider a quantum dot connected coherently to tunable electronic cavity modes. The structure is shown to exhibit a well-defined Kondo effect over a wide range of coupling strengths between the two subsystems. In agreement with recent experimental results, the calculated conductance curves exhibit strong modulations and asymmetric behavior as different cavity modes are swept through the Fermi level. These conductance modulations occur, however, while maintaining robust Kondo singlet correlations of the dot with the electronic reservoir, a direct consequence of the lopsided nature of the device.

  20. High-order optical vortex generation in a few-mode fiber via cascaded acoustically driven vector mode conversion.

    PubMed

    Zhang, Wending; Huang, Ligang; Wei, Keyan; Li, Peng; Jiang, Biqiang; Mao, Dong; Gao, Feng; Mei, Ting; Zhang, Guoquan; Zhao, Jianlin

    2016-11-01

    We propose a method to generate the high-order optical vortex in a few-mode fiber via cascaded acoustically driven vector mode conversion. Theoretical analysis showed that the vector mode conversion induced by the acoustically induced fiber grating (AIFG) could occur between two HE modes with adjacent azimuthal numbers. In the experiment conducted at 532 nm, two AIFGs were simultaneously induced in the same segment of the fiber by a radio frequency source containing two different frequency components. One AIFG was used to convert the left- and right-handed circular polarization fundamental modes to the ±1-order vortex modes, which were then further converted to the ±2-order vortex modes by the other AIFG. The topological charges of the vortex modes were verified using both coaxial and off-axial interference methods, showing typical signature patterns of spiral forms and forklike fringes, respectively.

  1. Business Continuity Management Plan

    DTIC Science & Technology

    2014-12-01

    13 B. BUSINESS IMPACT ANALYSIS ................................................................17 C. RECOVERY STRATEGY...Business Continuity Institute BCM business continuity management BCP business continuity plan BIA business impact analysis... environmental , health and safety ERP Enterprise Resource Planning FEMA Federal Emergency Management Agency FISMA Federal Information Security Management

  2. 7 CFR 1160.501 - Continuation referenda.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 9 2010-01-01 2009-01-01 true Continuation referenda. 1160.501 Section 1160.501... Order Miscellaneous § 1160.501 Continuation referenda. (a) The Secretary at any time may conduct a referendum among those persons who the Secretary determines were fluid milk processors during a...

  3. Electrically conductive composite material

    DOEpatents

    Clough, R.L.; Sylwester, A.P.

    1988-06-20

    An electrically conductive composite material is disclosed which comprises a conductive open-celled, low density, microcellular carbon foam filled with a non-conductive polymer or resin. The composite material is prepared in a two-step process consisting of first preparing the microcellular carbon foam from a carbonizable polymer or copolymer using a phase separation process, then filling the carbon foam with the desired non-conductive polymer or resin. The electrically conductive composites of the present invention has a uniform and consistent pattern of filler distribution, and as a result is superior over prior art materials when used in battery components, electrodes, and the like. 2 figs.

  4. Electrically conductive composite material

    DOEpatents

    Clough, Roger L.; Sylwester, Alan P.

    1989-01-01

    An electrically conductive composite material is disclosed which comprises a conductive open-celled, low density, microcellular carbon foam filled with a non-conductive polymer or resin. The composite material is prepared in a two-step process consisting of first preparing the microcellular carbon foam from a carbonizable polymer or copolymer using a phase separation process, then filling the carbon foam with the desired non-conductive polymer or resin. The electrically conductive composites of the present invention has a uniform and consistant pattern of filler distribution, and as a result is superior over prior art materials when used in battery components, electrodes, and the like.

  5. Electrically conductive composite material

    DOEpatents

    Clough, R.L.; Sylwester, A.P.

    1989-05-23

    An electrically conductive composite material is disclosed which comprises a conductive open-celled, low density, microcellular carbon foam filled with a non-conductive polymer or resin. The composite material is prepared in a two-step process consisting of first preparing the microcellular carbon foam from a carbonizable polymer or copolymer using a phase separation process, then filling the carbon foam with the desired non-conductive polymer or resin. The electrically conductive composites of the present invention has a uniform and consistent pattern of filler distribution, and as a result is superior over prior art materials when used in battery components, electrodes, and the like. 2 figs.

  6. Electrically conductive composite material

    SciTech Connect

    Clough, R.L.; Sylwester, A.P.

    1989-05-23

    An electrically conductive composite material is disclosed which comprises a conductive open-celled, low density, microcellular carbon foam filled with a non-conductive polymer or resin. The composite material is prepared in a two-step process consisting of first preparing the microcellular carbon foam from a carbonizable polymer or copolymer using a phase separation process, then filling the carbon foam with the desired non-conductive polymer or resin. The electrically conductive composites of the present invention has a uniform and consistent pattern of filler distribution, and as a result is superior over prior art materials when used in battery components, electrodes, and the like. 2 figs.

  7. 12 CFR 229.58 - Mode of delivery of information.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 3 2010-01-01 2010-01-01 false Mode of delivery of information. 229.58 Section 229.58 Banks and Banking FEDERAL RESERVE SYSTEM (CONTINUED) BOARD OF GOVERNORS OF THE FEDERAL RESERVE SYSTEM AVAILABILITY OF FUNDS AND COLLECTION OF CHECKS (REGULATION CC) Substitute Checks § 229.58 Mode...

  8. A tunable diode laser emitting orthogonally polarised radiation modes

    SciTech Connect

    Fadyushin, A B; Velichansky, Vladimir L; Senkov, N V; Lukin, M D; Scully, M O; Fleischauer, M

    2002-07-31

    A new scheme of the external cavity of a diode laser is described. The scheme provides emission of two closely spaced ({Delta}{lambda} < 10{sup -3} nm) orthogonally polarised modes, which can be tuned within the gain line, with the mode interval continuously changed. (lasers)

  9. Mode II fatigue crack propagation.

    NASA Technical Reports Server (NTRS)

    Roberts, R.; Kibler, J. J.

    1971-01-01

    Fatigue crack propagation rates were obtained for 2024-T3 bare aluminum plates subjected to in-plane, mode I, extensional loads and transverse, mode II, bending loads. These results were compared to the results of Iida and Kobayashi for in-plane mode I-mode II extensional loads. The engineering significance of mode I-mode II fatigue crack growth is considered in view of the present results. A fatigue crack growth equation for handling mode I-mode II fatigue crack growth rates from existing mode I data is also discussed.

  10. Mode Transitions in Magnetically Shielded Hall Effect Thrusters

    NASA Technical Reports Server (NTRS)

    Sekerak, Michael J.; Longmier, Benjamin W.; Gallimore, Alec D.; Huang, Wensheng; Kamhawi, Hani; Hofer, Richard R.; Jorns, Benjamin A.; Polk, James E.

    2014-01-01

    A mode transition study is conducted in magnetically shielded thrusters where the magnetic field magnitude is varied to induce mode transitions. Three different oscillatory modes are identified with the 20-kW NASA-300MS-2 and the 6-kW H6MS: Mode 1) global mode similar to unshielded thrusters at low magnetic fields, Mode 2) cathode oscillations at nominal magnetic fields, and Mode 3) combined spoke, cathode and breathing mode oscillations at high magnetic fields. Mode 1 exhibits large amplitude, low frequency (1-10 kHz), breathing mode type oscillations where discharge current mean value and oscillation amplitude peak. The mean discharge current is minimized while thrust-to-power and anode efficiency are maximized in Mode 2, where higher frequency (50-90 kHz), low amplitude, cathode oscillations dominate. Thrust is maximized in Mode 3 and decreases by 5-6% with decreasing magnetic field strength. The presence or absence of spokes and strong cathode oscillations do not affect each other or discharge current. Similar to unshielded thrusters, mode transitions and plasma oscillations affect magnetically shielded thruster performance and should be characterized during system development.

  11. The continuum of unstable magnetohydrodynamic modes in a simple magnetized atmosphere

    SciTech Connect

    Widdowson, S.; Hurricane, O.A.; Cowley, S.C.

    1998-05-01

    The spectrum of unstable perturbations of a simple magnetized atmosphere is studied. Magnetic field lines are straight, horizontal, and line tied to conducting walls at both ends. The temperature has horizontal variation across the field lines as well as vertical variation. The unstable spectrum close to marginal stability is found to be continuous from zero to a maximum growth rate. The structure of the unstable continuum modes is calculated in the dissipationless limit. The presence of singularities in the eigenfunction does not affect the growth rate significantly, nor does it lead to plasma heating. {copyright} {ital 1998 American Institute of Physics.}

  12. A minimalist operating mode for UKIRT

    NASA Astrophysics Data System (ADS)

    Kerr, Tom; Davis, Gary R.; Craig, Simon C.; Walther, Craig; Chuter, Tim

    2012-09-01

    In late 2010, driven by funding pressure from its governing body, the United Kingdom Infrared Telescope (UKIRT) underwent the most significant operational change in its history culminating in a new "minimalist mode" operation. Since 13th December 2010 this telescope, situated at the summit of Mauna Kea, Hawaii, has been operated remotely from the Joint Astronomy Centre in Hilo, with a priority on completing the UKIRT Infrared Deep Sky Survey (UKIDSS) but also continued support of other international programmes. In mid-2012, while remaining in minimalist mode, the observatory plans to start a new and ambitious near-infrared survey of the northern sky called the UKIRT Hemisphere Survey. The change to minimalist mode has resulted in the following: the cost of running the observatory has been reduced from 3.9M to 2.0M yet despite the changes, which included a reduction in staff and support, the UKIRT continues to operate at 90% efficiency, a level it has operated at for the last several years. The fault rate remains extremely low (approximately 3%) and has not been affected by remote operations and up until February 2012 no time-losing faults were attributed to operating remotely. This paper discusses the motivations behind the change to minimalist mode, the new mode of operation itself, the effect, if any, of the change on operational efficiency and the challenges facing a remotely operated telescope at a remote mountain site.

  13. Supersymmetric mode converters

    NASA Astrophysics Data System (ADS)

    Heinrich, Matthias; Miri, Mohammad-Ali; Stützer, Simon; Nolte, Stefan; Szameit, Alexander; Christodoulides, Demetrios N.

    2015-08-01

    In recent years, the ever-increasing demand for high-capacity transmission systems has driven remarkable advances in technologies that encode information on an optical signal. Mode-division multiplexing makes use of individual modes supported by an optical waveguide as mutually orthogonal channels. The key requirement in this approach is the capability to selectively populate and extract specific modes. Optical supersymmetry (SUSY) has recently been proposed as a particularly elegant way to resolve this design challenge in a manner that is inherently scalable, and at the same time maintains compatibility with existing multiplexing strategies. Supersymmetric partners of multimode waveguides are characterized by the fact that they share all of their effective indices with the original waveguide. The crucial exception is the fundamental mode, which is absent from the spectrum of the partner waveguide. Here, we demonstrate experimentally how this global phase-matching property can be exploited for efficient mode conversion. Multimode structures and their superpartners are experimentally realized in coupled networks of femtosecond laser-written waveguides, and the corresponding light dynamics are directly observed by means of fluorescence microscopy. We show that SUSY transformations can readily facilitate the removal of the fundamental mode from multimode optical structures. In turn, hierarchical sequences of such SUSY partners naturally implement the conversion between modes of adjacent order. Our experiments illustrate just one of the many possibilities of how SUSY may serve as a building block for integrated mode-division multiplexing arrangements. Supersymmetric notions may enrich and expand integrated photonics by versatile optical components and desirable, yet previously unattainable, functionalities.

  14. Mode Gaussian beam tracing

    NASA Astrophysics Data System (ADS)

    Trofimov, M. Yu.; Zakharenko, A. D.; Kozitskiy, S. B.

    2016-10-01

    A mode parabolic equation in the ray centered coordinates for 3D underwater sound propagation is developed. The Gaussian beam tracing in this case is constructed. The test calculations are carried out for the ASA wedge benchmark and proved an excellent agreement with the source images method in the case of cross-slope propagation. But in the cases of wave propagation at some angles to the cross-slope direction an account of mode interaction becomes necessary.

  15. Plants under continuous light.

    PubMed

    Velez-Ramirez, Aaron I; van Ieperen, Wim; Vreugdenhil, Dick; Millenaar, Frank F

    2011-06-01

    Continuous light is an essential tool for understanding the plant circadian clock. Additionally, continuous light might increase greenhouse food production. However, using continuous light in research and practice has its challenges. For instance, most of the circadian clock-oriented experiments were performed under continuous light; consequently, interactions between the circadian clock and the light signaling pathway were overlooked. Furthermore, in some plant species continuous light induces severe injury, which is only poorly understood so far. In this review paper, we aim to combine the current knowledge with a modern conceptual framework. Modern genomic tools and rediscovered continuous light-tolerant tomato species (Solanum spp.) could boost the understanding of the physiology of plants under continuous light. Copyright © 2011 Elsevier Ltd. All rights reserved.

  16. Pulse mode of laser photodynamic treatment induced cell apoptosis.

    PubMed

    Klimenko, Vladimir V; Knyazev, Nickolay A; Moiseenko, Fedor V; Rusanov, Anatoliy A; Bogdanov, Alexey A; Dubina, Michael V

    2016-03-01

    One of the factors limiting photodynamic therapy (PDT) is hypoxia in tumor cells during photodynamic action. PDT with pulse mode irradiation and appropriate irradiation parameters could be more effective in the singlet oxygen generation and tissue re-oxygenation than continuous wave (CW) mode. We theoretically demonstrate differences between the cumulative singlet oxygen concentration in PDT using pulse mode and CW mode of laser irradiation. In vitro experimental results show that photodynamic treatment with pulse mode irradiation has similar cytotoxicity to CW mode and induces mainly cell apoptosis, whereas CW mode induces necrotic cell death. We assume that the cumulative singlet oxygen concentration and the temporal distribution of singlet oxygen are important in photodynamic cytotoxicity and apoptosis initiation. We expect our research may improve irradiation protocols and photodynamic therapy efficiency.

  17. Continuous Glucose Monitoring

    PubMed Central

    Fritschi, Cynthia; Quinn, Laurie; Penckofer, Sue; Surdyk, Patricia M.

    2010-01-01

    Purpose The purpose of this descriptive study was to document the experience of wearing a continuous glucose monitoring (CGM) device in women with type 2 diabetes (T2DM). The availability of CGM has provided patients and clinicians with the opportunity to describe the immediate effects of diet, exercise, and medications on blood glucose levels; however, there are few data examining patients’ experiences and acceptability of using CGM. Methods Thirty-five women with T2DM wore a CGM for 3 days. Semistructured interviews were conducted to capture the self-described experience of wearing a CGM. Three open-ended questions were used to guide the participants’ self-reflection. Interviews were transcribed and analyzed. Results The women verbalized both positive and negative aspects of needing to check their blood glucose more frequently and wearing the monitor. After viewing the results, most women were surprised by the magnitude and frequency of blood glucose excursions. They immediately examined their behaviors during the time they wore the CGM. Independent problem-solving skills became apparent as they attempted to identify reasons for hyperglycemia by retracing food intake, physical activity, and stress experiences during the period of CGM. Most important, the majority of women stated they were interested in changing their diabetes-related self-care behaviors, especially eating and exercise behaviors, after reviewing their CGM results. Conclusions CGM is generally acceptable to women with T2DM and offers patients and their health care practitioners a possible alternative to routine glucose monitoring for assessing the effects of real-life events on blood glucose levels. PMID:20016057

  18. Above room temperature continuous wave operation of a broad-area quantum-cascade laser

    NASA Astrophysics Data System (ADS)

    Semtsiv, M. P.; Masselink, W. T.

    2016-11-01

    We describe the design and implementation of a broad-area (w ≈ 30 μm) quantum-cascade laser operating in a continuous wave mode up to heat-sink temperatures beyond +100 °C. The room-temperature emission wavelength is 4.6 μm. The temperature gradient in the active region of such a wide laser stripe is essentially perpendicular to the epitaxial layers and the resulting steady-state active region temperature offset scales approximately with the square of the number of cascades. With only 10 cascades in the active region, the threshold electrical power density in the current quantum-cascade laser in the continuous-wave mode is as low as Vth × Ith = 3.8 V × 0.9 kA/cm2 = 3.4 kW/cm2 at room temperature for 2 mm-long two-side high-reflectivity coated laser stripe. A 4 mm-long one-side high-reflectivity coated laser stripe delivers in continuous-wave mode above 0.6 W at +20 °C and above 1.3 W at -27 °C (cooled with a single-stage Peltier element). A 2 mm-long two-side high-reflectivity coated laser stripe demonstrates continuous-wave lasing up to at least +102 °C (375 K). The thermal conductance, Gth, ranges between 235 W/K cm2 and 140 W/K cm2 for temperatures between -33 °C and +102 °C. This demonstration opens the route for continuous-wave power scaling of quantum-cascade lasers via broad-area laser ridges.

  19. Low conductivity thermal barrier coatings

    NASA Astrophysics Data System (ADS)

    Zhao, Hengbei

    The dissertation begins by exploring the growth of 7YSZ coatings at different rotation rates. The experiments show that as the rotation rate was increased, the texture changes from <111> to <100> and the total pore fraction slowly decreased. The intercolumnar pores perpendicular to the coating surface are very effective at strain accommodation during thermal cycling. The intra-columnar pores appear the most effective for the reduction of thermal conductivity of the coatings. The minimum thermal conductivity occurs at a low rotation rate and is 0.8 W/mK. The failure modes and mechanisms of 7YSZ coatings during thermal cycling have been investigated. The primary mode of failure on rough bond coat surfaces involves delamination within the ceramic coating, just above the thermally-grown oxide (TGO). It was initiated by a bond coat rumpling mechanism. The delaminations were initiated preferentially at "corn kernel" growth defects in the coating. Ceramic coatings applied to polished bond coat surfaces had much longer spallation lifetimes and the delamination fracture shifted to the interface of TGO/bond coat. These delaminations were extended by a mechanism involving the formation and coalescence of interfacial voids. The enhanced coating life is shown to be a consequence of their lower density and hence, lower elastic modulus. Rare earth zirconates appear to be a promising candidate due to their reported low intrinsic thermal conductivity, good phase stability and greater resistance to sintering and CMAS attack compared to 7YSZ. The SZO coatings had as-deposited conductivities of 0.5+/-0.1 W/mK. When these SZO coatings were subjected to thermal cycling, it was found to have a much shorter lifetime (on both rough and smooth bond coats) than similarly deposited 7YSZ material. It was also found that samaria tended to react with alumina to form a SmAlO 3 interphase of the TBC/TGO interface which appears to significantly lower the interface toughness. To improve the

  20. SESAM mode-locked red praseodymium laser.

    PubMed

    Gaponenko, Maxim; Metz, Philip Werner; Härkönen, Antti; Heuer, Alexander; Leinonen, Tomi; Guina, Mircea; Südmeyer, Thomas; Huber, Günter; Kränkel, Christian

    2014-12-15

    We present the first semiconductor saturable absorber mirror (SESAM) mode-locked praseodymium solid-state laser. The laser is based on a Pr(3+):LiYF(4) crystal as gain medium and a GaInP-quantum well-based SESAM. Self-starting continuous-wave mode-locked laser operation with an average output power of 16 mW is achieved at a center wavelength of 639.5 nm. The laser operates at a repetition rate of ∼85.55  MHz and emits pulses with a duration of ∼18  ps.