WorldWideScience

Sample records for width modulation control

  1. Feedback control of electrically stimulated muscle using simultaneous pulse width and stimulus period modulation.

    Science.gov (United States)

    Chizeck, H J; Lan, N; Palmieri, L S; Crago, P E

    1991-12-01

    This paper considers the closed-loop control of electrically stimulated muscle using simultaneous pulse width and frequency modulation. Previous work has experimentally demonstrated good feedback regulation of muscle force using fixed parameter and an adaptive controller modulating pulse width. In this work, it is shown how the addition of pulse frequency modulation to pulse width modulation can improve controller performance. This combination controller has been developed for both single muscle activation and for costimulation of antagonists. This is accomplished using a single command input. In single muscle operation, the combination of pulse width and stimulus pulse frequency modulation results in better control of transient responses than with pulse width modulation alone; the total number of stimulus pulses is increased, however, when compared with pulse width-only modulation at the muscle fusion frequency. In the case of costimulation, the controller modulates the pulse stimulus periods of the antagonists in a reciprocal manner, to ensure stable and fast responses. That is, the frequency of stimulation of the antagonist is increased when that of the agonist is decreased. This results in better control performance with generally fewer stimulus pulses than those generated by costimulation using only pulse width modulation. This feedback controller was evaluated in animal experiments. Step responses with rapid rise times but without overshoot were obtained by the combined modulation. Good steady-state and transient performance were obtained over a wide range of static lengths and commands, under different loading conditions and in different animals. This controller is a promising potential component of neural prostheses to restore functional movement in paralyzed individuals.

  2. Fuzzy control with amplitude/pulse-width modulation of nerve electrical stimulation for muscle force control

    Science.gov (United States)

    Lin, C.-C. K.; Liu, W.-C.; Chan, C.-C.; Ju, M.-S.

    2012-04-01

    The main goal of this study was to study the performance of fuzzy logic controllers combined with simplified hybrid amplitude/pulse-width (AM/PW) modulation to regulate muscle force via nerve electrical stimulation. The recruitment curves with AM/PW and AM modulations were constructed for the calf muscles of rabbits. Integrated with the modulation methods, a proportional-integral-derivative (PID) and three fuzzy logic controllers were designed and applied for the electrical stimulation of tibial nerves to control the ankle torque under isometric conditions. The performance of the two modulation methods combined with the four controllers was compared when the ankle was fixed at three positions for both in vivo experiments and model simulations using a nonlinear muscle model. For the animal experiments, AM/PW modulation performed better than AM modulation alone. The fuzzy PI controller performed marginally better and was resistant to external noises, though it tended to have a larger overshoot. The performance of the controllers had a similar trend in the three different joint positions, and the simulation results with the nonlinear model matched the experimental results well. In conclusion, AM/PW modulation improved controller performance, while the contribution of fuzzy logic was only marginal.

  3. Fuzzy control with amplitude/pulse-width modulation of nerve electrical stimulation for muscle force control.

    Science.gov (United States)

    Lin, C-C K; Liu, W-C; Chan, C-C; Ju, M-S

    2012-04-01

    The main goal of this study was to study the performance of fuzzy logic controllers combined with simplified hybrid amplitude/pulse-width (AM/PW) modulation to regulate muscle force via nerve electrical stimulation. The recruitment curves with AM/PW and AM modulations were constructed for the calf muscles of rabbits. Integrated with the modulation methods, a proportional-integral-derivative (PID) and three fuzzy logic controllers were designed and applied for the electrical stimulation of tibial nerves to control the ankle torque under isometric conditions. The performance of the two modulation methods combined with the four controllers was compared when the ankle was fixed at three positions for both in vivo experiments and model simulations using a nonlinear muscle model. For the animal experiments, AM/PW modulation performed better than AM modulation alone. The fuzzy PI controller performed marginally better and was resistant to external noises, though it tended to have a larger overshoot. The performance of the controllers had a similar trend in the three different joint positions, and the simulation results with the nonlinear model matched the experimental results well. In conclusion, AM/PW modulation improved controller performance, while the contribution of fuzzy logic was only marginal.

  4. Sliding mode pulse-width modulation technique for direct torque controlled induction motor drive

    Science.gov (United States)

    Bounadja, M.; Belarbi, A. W.; Belmadani, B.

    2010-05-01

    This paper presents a novel pulse-width modulation technique based sliding mode approach for direct torque control of an induction machine drive. Methodology begins with a sliding mode control of machine's torque and stator flux to generate the reference voltage vector and to reduce parameters sensitivity. Then, the switching control of the three-phase inverter is developed using sliding mode concept to make the system tracking reference voltage inputs. The main features of the proposed methodologies are the high tracking accuracy and the much easier implementation compared to the space vector modulation. Simulations are carried out to confirm the effectiveness of proposed control algorithms.

  5. Method and apparatus for pulse width modulation control of an AC induction motor

    Science.gov (United States)

    Geppert, Steven (Inventor); Slicker, James M. (Inventor)

    1984-01-01

    An inverter is connected between a source of DC power and a three-phase AC induction motor, and a micro-processor-based circuit controls the inverter using pulse width modulation techniques. In the disclosed method of pulse width modulation, both edges of each pulse of a carrier pulse train are equally modulated by a time proportional to sin .THETA., where .THETA. is the angular displacement of the pulse center at the motor stator frequency from a fixed reference point on the carrier waveform. The carrier waveform frequency is a multiple of the motor stator frequency. The modulated pulse train is then applied to each of the motor phase inputs with respective phase shifts of 120.degree. at the stator frequency. Switching control commands of electronic switches in the inverter are stored in a random access memory (RAM) and the locations of the RAM are successively read out in a cyclic manner, each bit of a given RAM location controlling a respective phase input of the motor. The DC power source preferably comprises rechargeable batteries and all but one of the electronic switches in the inverter can be disabled, the remaining electronic switch being part of a flyback DC-DC converter circuit for recharging the battery.

  6. Single Event Effects Testing of the Linfinity SG1525A Pulse Width Modulator Controller

    Science.gov (United States)

    Howard, J. W., Jr.; Carts, M. A.; LaBel, K. A.; Forney, J. D.; Irwin, T. L.

    2003-01-01

    Pulse Width Modulator (PWM) Controllers are the heart of switching power supply systems in development today. The PWMs considered here have the same integration advantages as many other controllers but it also includes the interface drivers for the follow-on power Field Effect Transistors (FET). Previous work on these types of devices looked into the required test methodologies [ 11 and the impact of radiation on the soft start and shutdown circuits of typically incorporated in the technology [2]. Taking advantage of this previous work this study was undertaken to determine the single event destructive and transient susceptibility of the Linfinity SG1525A Pulse Width Modulator Controller. The device was monitored for transient interruptions in the output signals and for destructive events induced by exposing it to a heavy ion beam at the Texas A&M University Cyclotron Single Event Effects Test Facility. After exposing these devices to the beam, a new upset mode has been identified that can lead to catastrophic power supply system failure if this event would occur while drive power FETs off the two device outputs. The devices and the test methods used will be described first. This will be followed by a brief description of the data collected to date (not all data can be presented with the length constraints of the summary) and a summary of the key results.

  7. Pulse width modulation-based temperature tracking for feedback control of a shape memory alloy actuator.

    Science.gov (United States)

    Ayvali, Elif; Desai, Jaydev P

    2014-04-01

    This work presents a temperature-feedback approach to control the radius of curvature of an arc-shaped shape memory alloy (SMA) wire. The nonlinear properties of the SMA such as phase transformation and its dependence on temperature and stress make SMA actuators difficult to control. Tracking a desired trajectory is more challenging than controlling just the position of the SMA actuator since the desired path is continuously changing. Consequently, tracking the desired strain directly or tracking the parameters such as temperature and electrical resistance that are related to strain with a model is a challenging task. Temperature-feedback is an attractive approach when direct measurement of strain is not practical. Pulse width modulation (PWM) is an effective method for SMA actuation and it can be used along with a compensator to control the temperature of the SMA. Using the constitutive model of the SMA, the desired temperature profile can be obtained for a given strain trajectory. A PWM-based nonlinear PID controller with a feed-forward heat transfer model is proposed to use temperature-feedback for tracking a desired temperature trajectory. The proposed controller is used during the heating phase of the SMA actuator. The controller proves to be effective in tracking step-wise and continuous trajectories.

  8. Analysis of Pulse Modulated Control Systems (Ⅲ) Stability of Systems with Pulse Frequency Modulation and Systems with Combined Pulse Frequency and Pulse Width Modulation

    OpenAIRE

    OI,Shigemitsu

    1993-01-01

    Sufficient conditions for finite pulse stability of interconnected systems with combined pulse frequency and pulse width modulation are developed in this paper using a direct method. The stability criteria established provide upper bounds on the number of pulses emitted by each modulator. The results are also applicable to those systems which contain a finite number of pulse frequency modulators and a finite number of combined pulse frequency and pulse width modulators

  9. Red and blue pulse timing control for pulse width modulation light dimming of light emitting diodes for plant cultivation.

    Science.gov (United States)

    Shimada, Aoi; Taniguchi, Yoshio

    2011-09-02

    A pulse width modulation (PWM) light dimming system containing red and blue light emitting diodes was designed and constructed. Cultivation of the plant Arabidopsis thaliana under various light dimming wave patterns was compared. Control of the pulse timing (phase of wave pattern) between red and blue light in PWM light dimming was examined. Different plant growth was obtained by changing the phase of red and blue pulses. Pulse timing control of PWM light dimming for plant cultivation has the potential to act as a method for probing photosynthesis. Copyright © 2011 Elsevier B.V. All rights reserved.

  10. A pulse-width modulation controlled wire-mesh heater apparatus for investigation of solid fuel pyrolysis.

    Science.gov (United States)

    Wagner, David Ray; Whitty, Kevin J

    2012-11-01

    A novel wire mesh heater apparatus has been developed to study the devolatilization of solid fuels under pressurized conditions at well-controlled heating rates on the order of 1000 K/s. The apparatus combines direct current and pulse-width modulation with a fast-acting and high current-capacity relay to achieve operating frequencies up to 2000 Hz. This frequency allows much quicker feedback and tighter control of temperature than conventional ac-based systems that operate at 50 to 60 Hz. The present apparatus has been successfully operated at 63 bars with final temperatures of 1473 K and heating rates of 1100 K/s.

  11. Healthy younger and older adults control foot placement to avoid small obstacles during gait primarily by modulating step width

    Directory of Open Access Journals (Sweden)

    Schulz Brian W

    2012-10-01

    Full Text Available Abstract Background Falls are a significant problem in the older population. Most falls occur during gait, which is primarily regulated by foot placement. Variability of foot placement has been associated with falls, but these associations are inconsistent and generally for smooth, level flooring. This study investigates the control of foot placement and the associated gait variability in younger and older men and women (N=7/group, total N=28 while walking at three different speeds (slow, preferred, and fast across a control surface with no obstacles and surfaces with multiple (64 small (10cm long ×13mm high visible and hidden obstacles. Results Minimum obstacle distance between the shoe and nearest obstacle during each footfall was greater on the visible obstacles surface for older subjects because some of them chose to actively avoid obstacles. This obstacle avoidance strategy was implemented primarily by modulating step width and to a lesser extent step length as indicated by linear regressions of step width and length variability on minimum obstacle distance. Mean gait speed, step length, step width, and step time did not significantly differ by subject group, flooring surface, or obstacle avoidance strategy. Conclusions Some healthy older subjects choose to actively avoid small obstacles that do not substantially perturb their gait by modulating step width and, to a lesser extent, step length. It is not clear if this obstacle avoidance strategy is appropriate and beneficial or overcautious and maladaptive, as it results in fewer obstacles encountered at a consequence of a less efficient gait pattern that has been shown to indicate increased fall risk. Further research is needed on the appropriateness of strategy selection when the environmental demands and/or task requirements have multiple possible completion strategies with conflicting objectives (i.e. perceived safety vs. efficiency.

  12. Design and Simulation of Control Technique for Permanent Magnet Synchronous Motor Using Space Vector Pulse Width Modulation

    Science.gov (United States)

    Khan, Mansoor; Yong, Wang; Mustafa, Ehtasham

    2017-07-01

    After the rapid advancement in the field of power electronics devices and drives for last few decades, there are different kinds of Pulse Width Modulation techniques which have been brought to the market. The applications ranging from industrial appliances to military equipment including the home appliances. The vey common application for the PWM is three phase voltage source inverter, which is used to convert DC to AC in the homes to supply the power to the house in case electricity failure, usually named as Un-interrupted Power Supply. In this paper Space Vector Pulse Width Modulation techniques is discussed and analysed under the control technique named as Field Oriented Control. The working and implementation of this technique has been studied by implementing on the three phase bridge inverter. The technique is used to control the Permanente Magnet Synchronous Motor. The drive system is successfully implemented in MATLAB/Simulink using the mathematical equation and algorithm to achieve the satisfactory results. PI type of controller is used to tuned ers of the motothe parametr i.e. torque and current.

  13. A pulse-width modulated, high reliability charge controller for small photovoltaic systems

    Energy Technology Data Exchange (ETDEWEB)

    Gerken, K. [Morningstar Corp., Olney, MD (United States); Welsh, D. [Morningstar Corp., Encinitas, CA (United States)

    1997-02-01

    This report presents the results of a development effort to design, test and begin production of a new class of small photovoltaic (PV) charge controllers. Sandia National Laboratories provided technical support, test data and financial support through a Balance-of-System Development contract. One of the objectives of the development was to increase user confidence in small PV systems by improving the reliability and operating life of the system controllers. Another equally important objective was to improve the economics of small PV systems by extending the battery lifetimes. Using new technology and advanced manufacturing techniques, these objectives were accomplished. Because small stand-alone PV systems account for over one third of all PV modules shipped, the positive impact of improving the reliability and economics of PV systems in this market segment will be felt throughout the industry. The results of verification testing of the new product are also included in this report. The initial design goals and specifications were very aggressive, but the extensive testing demonstrates that all the goals were achieved. Production of the product started in May at a rate of 2,000 units per month. Over 40 Morningstar distributors (5 US and 35 overseas) have taken delivery in the first 2 months of shipments. Initial customer reactions to the new controller have been very favorable.

  14. Pulse width modulation inverter with battery charger

    Science.gov (United States)

    Slicker, James M. (Inventor)

    1985-01-01

    An inverter is connected between a source of DC power and a three-phase AC induction motor, and a microprocessor-based circuit controls the inverter using pulse width modulation techniques. In the disclosed method of pulse width modulation, both edges of each pulse of a carrier pulse train are equally modulated by a time proportional to sin .theta., where .theta. is the angular displacement of the pulse center at the motor stator frequency from a fixed reference point on the carrier waveform. The carrier waveform frequency is a multiple of the motor stator frequency. The modulated pulse train is then applied to each of the motor phase inputs with respective phase shifts of 120.degree. at the stator frequency. Switching control commands for electronic switches in the inverter are stored in a random access memory (RAM) and the locations of the RAM are successively read out in a cyclic manner, each bit of a given RAM location controlling a respective phase input of the motor. The DC power source preferably comprises rechargeable batteries and all but one of the electronic switches in the inverter can be disabled, the remaining electronic switch being part of a flyback DC-DC converter circuit for recharging the battery.

  15. Digital Pulse-Width-Modulation Circuit

    Science.gov (United States)

    Wenzler, Carl J.; Eichenberg, Dennis J.

    1995-01-01

    Digital pulse-width-modulation circuit provides programmable duration from 1 microsecond to full on, at repetition rate of 1 kHz. Designed for use in controlling CO2 laser, also used in applications in which precision and flexibility of digital control of pulse durations needed. Circuit incorporates low-power Schottky transistor/transistor-logic (TTL) devices in critical high-speed parts. Designed in TTL to make it compatible with Pro-Log 7914 (or equivalent) decoder input/output (I/O) utility printed-circuit card.

  16. Simple Neutral-Point Voltage Control for Three-Level Inverters Using a Discontinuous Pulse Width Modulation

    DEFF Research Database (Denmark)

    Choi, Uimin; Lee, K.B.; Lee, Hyun-Hee

    2013-01-01

    This paper proposes a neutral-point voltage balancing method for a three-level inverter that uses discontinuous pulse width modulation (DPWM). The performance of a three-level inverter system is affected by the neutral-point voltage unbalancing. Therefore, the voltages of series connected dc...

  17. Comparative evaluation of modified pulse width modulation ...

    African Journals Online (AJOL)

    Comparative evaluation of modified pulse width modulation schemes of Z-source inverter for various applications and demands. ... In this paper, for the common boost factor and modulation index, the output voltage, output current, output line harmonics profile of the inverters with different PWM schemes powered by the ...

  18. Modified Synchronous Reference Frame Based Shunt Active Power Filter with Fuzzy Logic Control Pulse Width Modulation Inverter

    Directory of Open Access Journals (Sweden)

    Suleiman Musa

    2017-05-01

    Full Text Available Harmonic distortion in power networks has greatly reduced power quality and this affects system stability. In order to mitigate this power quality issue, the shunt active power filter (SAPF has been widely applied and it is proven to be the best solution to current harmonics. This paper evaluates the performance of the modified synchronous reference frame extraction (MSRF algorithm with fuzzy logic controller (FLC based current control pulse width modulation (PWM inverter of three-phase three-wire SAPF to mitigate current harmonics. The proposed FLC is designed with a reduced amount of membership functions (MFs and rules, and thus significantly reduces the computational time and memory size. Modeling and simulations of SAPF are carried out using MATLAB/Simulink R2012a with the power system toolbox under steady-state condition, and this is followed with hardware implementation using a TMS320F28335 digital signal processor (DSP, Specrum Digital Inc., Stafford, TX, USA. The results obtained demonstrate a good and satisfactory response to mitigate the harmonics in the system. The total harmonic distortion (THD for the system has been reduced from 25.60% to 0.92% and 1.41% in the simulation study with and without FLC, respectively. Similarly for the experimental study, the SAPF can compensate for the three-phase load current by reducing THD to 5.07% and 7.4% with and without FLC, respectively.

  19. Wireline equalization using pulse-width modulation

    NARCIS (Netherlands)

    Schrader, J.H.R.; Klumperink, Eric A.M.; Visschers, J.L.; Nauta, Bram

    2006-01-01

    Abstract-High-speed data links over copper cables can be effectively equalized using pulse-width modulation (PWM) pre-emphasis. This provides an alternative to the usual 2-tap FIR filters. The use of PWM pre-emphasis allows a channel loss at the Nyquist frequency of ~30dB, compared to ~20dB for a

  20. Electrical system for pulse-width modulated control of a power inverter using phase-shifted carrier signals and related operating methods

    Science.gov (United States)

    Welchko, Brian A [Torrance, CA

    2012-02-14

    Systems and methods are provided for pulse-width modulated control of power inverter using phase-shifted carrier signals. An electrical system comprises an energy source and a motor. The motor has a first set of windings and a second set of windings, which are electrically isolated from each other. An inverter module is coupled between the energy source and the motor and comprises a first set of phase legs coupled to the first set of windings and a second set of phase legs coupled to the second set of windings. A controller is coupled to the inverter module and is configured to achieve a desired power flow between the energy source and the motor by modulating the first set of phase legs using a first carrier signal and modulating the second set of phase legs using a second carrier signal. The second carrier signal is phase-shifted relative to the first carrier signal.

  1. Circuit multiplies pulse width modulation, exhibits linear transfer function

    Science.gov (United States)

    Carlson, A. W.; Furciniti, A.

    1967-01-01

    Modulation multiplier provides a simple means of multiplying the width modulation of a pulse train by a constant factor. It operates directly on a pulse width modulated input signal to generate an output pulse train having a greater degree of width modulation than the input signal.

  2. Pulse-Width-Modulating Driver for Brushless dc Motor

    Science.gov (United States)

    Salomon, Phil M.

    1991-01-01

    High-current pulse-width-modulating driver for brushless dc motor features optical coupling of timing signals from low-current control circuitry to high-current motor-driving circuitry. Provides high electrical isolation of motor-power supply, helping to prevent fast, high-current motor-driving pulses from being coupled through power supplies into control circuitry, where they interfere with low-current control signals.

  3. Width-modulated square-wave pulses for ultrasound applications.

    Science.gov (United States)

    Smith, Peter R; Cowell, David M J; Freear, Steven

    2013-11-01

    A method of output pressure control for ultrasound transducers using switched excitation is described. The method generates width-modulated square-wave pulse sequences that are suitable for driving ultrasound transducers using MOSFETs or similar devices. Sequences are encoded using an optimized level-shifted, carrier-comparison, pulse-width modulation (PWM) strategy derived from existing PWM theory, and modified specifically for ultrasound applications. The modifications are: a reduction in carrier frequency so that the smallest number of pulses are generated and minimal switching is necessary; alteration of a linear carrier form to follow a trigonometric relationship in accordance with the expected fundamental output; and application of frequency modulation to the carrier when generating frequency-modulated, amplitude- tapered signals. The PWM method permits control of output pressure for arbitrary waveform sequences at diagnostic frequencies (approximately 5 MHz) when sampled at 100 MHz, and is applicable to pulse shaping and array apodization. Arbitrary waveform generation capability is demonstrated in simulation using convolution with a transducer's impulse response, and experimentally with hydrophone measurement. Benefits in coded imaging are demonstrated when compared with fixed-width square-wave (pseudo-chirp) excitation in coded imaging, including reduction in image artifacts and peak side-lobe levels for two cases, showing 10 and 8 dB reduction in peak side-lobe level experimentally, compared with 11 and 7 dB reduction in simulation. In all cases, the experimental observations correlate strongly with simulated data.

  4. Fractal Reference Signals in Pulse-Width Modulation

    Science.gov (United States)

    Lurie, Boris; Lurie, Helen

    2005-01-01

    A report proposes the use of waveforms having fractal shapes reminiscent of sawteeth (in contradistinction to conventional regular sawtooth waveforms) as reference signals for pulse-width modulation in control systems for thrusters of spacecraft flying in formation. Fractal reference signals may also be attractive in some terrestrial control systems - especially those in which pulse-width modulation is used for precise control of electric motors. The report asserts that the use of fractal reference signals would enable the synchronous control of several variables of a spacecraft formation, such that consumption of propellant would be minimized, intervals between thruster firings would be long (as preferred for performing scientific observations), and delays in controlling large-thrust maneuvers for retargeting would be minimized. The report further asserts that whereas different controllers would be needed for different modes of operation if conventional pulsewidth modulation were used, the use of fractal reference signals would enable the same controller to function nearly optimally in all regimes of operation, so that only this one controller would be needed.

  5. Global synchronization of parallel processors using clock pulse width modulation

    Science.gov (United States)

    Chen, Dong; Ellavsky, Matthew R.; Franke, Ross L.; Gara, Alan; Gooding, Thomas M.; Haring, Rudolf A.; Jeanson, Mark J.; Kopcsay, Gerard V.; Liebsch, Thomas A.; Littrell, Daniel; Ohmacht, Martin; Reed, Don D.; Schenck, Brandon E.; Swetz, Richard A.

    2013-04-02

    A circuit generates a global clock signal with a pulse width modification to synchronize processors in a parallel computing system. The circuit may include a hardware module and a clock splitter. The hardware module may generate a clock signal and performs a pulse width modification on the clock signal. The pulse width modification changes a pulse width within a clock period in the clock signal. The clock splitter may distribute the pulse width modified clock signal to a plurality of processors in the parallel computing system.

  6. Development of microheaters for gas sensor with an AT-Mega 8535 temperature controller using a PWM (pulse width modulation) method

    Energy Technology Data Exchange (ETDEWEB)

    Megayanti, Meti; Panatarani, Camellia; Joni, I. Made, E-mail: imadejoni@phys.unpad.ac.id [Instrumentation System and Functional Material Processing Laboratory, Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Padjadjaran Jalan Raya Bandung-Sumedang KM 21, Jatinangor 45363, West Java (Indonesia)

    2016-03-11

    Microheater is the main component in gas sensor characterized by their sensitivity, selectivity, and time response of gas sensor which is depend on the microheater temperature stability. A Cu microheater was developed and utilized AT-Mega 8535 controller using a PWM (pulse width modulation) method. This control system is interfaced to the PC to observe the real time temperature response of the microheater. Three initial resistance (R0) variations of microheater were developed in an open loop control system. The power characteristic of designed microheater depends on the specified microheater initial resistance. The smaller R0, the less power required to reach a temperature setting value. The developed microheater was designed to reach a temperature setting value of 250°C having resistance 0.531 Ω for 1.979 Watt and 0.265 Ω for 1.072 Watt respectively. The results of the investigation on the control performances shows microheater-control system achieved operating temperature up to 250°C. The response of the temperature control shows smallest R0 resulted in a high stability with short settling time, short delay time and small ripple for temperature setting values higher than 150°C. The obtained error of microheater temperature with R0 = 0.265 is 8.596 %. It is concluded that the developed microheater can be utilized as a component of a gas sensor.

  7. High-frequency modelling of a three-phase pulse width modulation inverter towards the dc bus considering line and controller harmonics

    Directory of Open Access Journals (Sweden)

    Saeid Haghbin

    2014-10-01

    Full Text Available Closed-form analytical formulas are provided to calculate the dc bus harmonics of a three-phase sinusoidal pulse width modulation (SPWM inverter. The harmonic analysis is performed by using a double Fourier series approach to determine the dc bus current frequency spectrum. For an arbitrary modulation index and load power factor, the full harmonic components of the inverter dc side current are calculated. Based on the developed analytical model, an equivalent circuit is proposed for the inverter harmonic analysis towards the dc bus. Moreover, the impacts of line harmonics and zero sequence injection in controller towards the dc bus are presented. The results show that the 5th and 7th ac line harmonics on the dc side current is appearance of the 6th harmonic in the dc side. The impact of zero sequence injection to the controller on the dc side is negligible. In addition to analytical formulation, different simulations and extensive measurements performed which the results verified the presented analytical framework.

  8. A New Selective Harmonic Elimination Pulse- Width and Amplitude Modulation (SHEPWAM) for Drive Applications

    DEFF Research Database (Denmark)

    Ghoreishy, Hoda; Varjani, Ali Yazdian; Mohamadian, Mustafa

    2013-01-01

    Compared to the conventional selective harmonic elimination-pulse width modulation (SHE-PWM), the selective harmonic elimination-pulse width and amplitude modulation (SHE-PWAM) control strategy results in significant improvements in the performance of CHB inverters. This fact is due to considering...

  9. An Efficient Space Vector Pulse Width Modulation with BFO Based Self Tuning PI Controller for Shunt Active Power Filter

    OpenAIRE

    P. Saravanan; P.A. Balakrishnan

    2014-01-01

    This research study mainly focuses on using an efficient control strategy for extracting reference currents of shunt active filters under non linear load conditions. In recent decades, the utilization of highly automatic electric equipments has resulted in enormous economic loss. Thus, the power suppliers as well as the power consumers are very much concerned about the power quality issues and compensation approaches. In order to deal with this issue, Active Power Filter (APF) has been consid...

  10. Pulse-width modulated DC-DC power converters

    CERN Document Server

    Kazimierczuk, Marian K

    2008-01-01

    This book studies switch-mode power supplies (SMPS) in great detail. This type of converter changes an unregulated DC voltage into a high-frequency pulse-width modulated (PWM) voltage controlled by varying the duty cycle, then changes the PWM AC voltage to a regulated DC voltage at a high efficiency by rectification and filtering. Used to supply electronic circuits, this converter saves energy and space in the overall system. With concept-orientated explanations, this book offers state-of-the-art SMPS technology and promotes an understanding of the principle operations of PWM converters,

  11. Harmonic Orientation of Pulse Width Modulation Technique in Multilevel Inverters

    OpenAIRE

    Urmila Bandaru; Subba D Rayudu

    2011-01-01

    The Multilevel Inverter topology gives the advantages of usage in high power and high voltage application with reduced harmonic distortion without a transformer. This paper presents a comparative study of orientation of higher ordered harmonics with increase in switching frequency around the frequency modulation index of nine level diode clamped inverter for different Switching frequency Multicarrier Pulse width Modulation.

  12. Energy detection UWB system based on pulse width modulation

    Directory of Open Access Journals (Sweden)

    Song Cui

    2014-05-01

    Full Text Available A new energy detection ultra-wideband system based on pulse width modulation is proposed. The bit error rate (BER performance of this new system is slightly worst than that of a pulse position modulation (PPM system in additive white Gaussian noise channels. In multipath channels, this system does not suffer from cross-modulation interference as PPM, so it can achieve better BER performance than PPM when cross-modulation interference occurs. In addition, when synchronisation errors occur, this system is more robust than PPM.

  13. Utility Interfaced Pulse-Width Modulation of Solar Fed Voltage ...

    African Journals Online (AJOL)

    This paper describes a utility interfaced pulse-width modulation of solar-fed voltage source single phase full bridge inverter. The proposed system has to do with the conversion of solar energy into electrical energy; boosting the dc power; inversion of the dc to ac and then synchronization of the inverter output with the utility, ...

  14. Programming microbes using pulse width modulation of optical signals.

    Science.gov (United States)

    Davidson, Eric A; Basu, Amar S; Bayer, Travis S

    2013-11-15

    Cells transmit and receive information via signalling pathways. A number of studies have revealed that information is encoded in the temporal dynamics of these pathways and has highlighted how pathway architecture can influence the propagation of signals in time and space. The functional properties of pathway architecture can also be exploited by synthetic biologists to enable precise control of cellular physiology. Here, we characterised the response of a bacterial light-responsive, two-component system to oscillating signals of varying frequencies. We found that the system acted as a low-pass filter, able to respond to low-frequency oscillations and unable to respond to high-frequency oscillations. We then demonstrate that the low-pass filtering behavior can be exploited to enable precise control of gene expression using a strategy termed pulse width modulation (PWM). PWM is a common strategy used in electronics for information encoding that converts a series of digital input signals to an analog response. We further show how the PWM strategy extends the utility of bacterial optogenetic control, allowing the fine-tuning of expression levels, programming of temporal dynamics, and control of microbial physiology via manipulation of a metabolic enzyme. © 2013. Published by Elsevier Ltd. All rights reserved.

  15. A microfluidic diluter based on pulse width flow modulation.

    Science.gov (United States)

    Ainla, Alar; Gözen, Irep; Orwar, Owe; Jesorka, Aldo

    2009-07-01

    We demonstrate that pulse width flow modulation (PWFM) can be used to design fast, accurate, and precise multistage dilution modules for microfluidic devices. The PWFM stage unit presented here yields 10-fold dilution, but several PWFM stages can be connected in series to yield higher-order dilutions. We have combined two stages in a device thus capable of diluting up to 100-fold, and we have experimentally determined a set of rules that can be conveniently utilized to design multistage diluters. Microfabrication with resist-based molds yielded geometrical channel height variances of 7% (22.9(16) microm) with corresponding hydraulic resistance variances of approximately 20%. Pulsing frequencies, channel lengths, and flow pressures can be chosen within a wide range to establish the desired diluter properties. Finally, we illustrate the benefits of on-chip dilution in an example application where we investigate the effect of the Ca(2+) concentration on a phospholipid bilayer spreading from a membrane reservoir onto a SiO(2) surface. This is one of many possible applications where flexible concentration control is desirable.

  16. space vector pulse width modulation of a multi-level diode clamped ...

    African Journals Online (AJOL)

    ES Obe

    Abstract. This paper presents the analysis of a multi-level diode clamped converter (DCC) which is implemented using space-vector pulse width modulation (SVPWM) tech- nique, widely considered as the most efficient and easily applied modulation tech- nique in most industrial drives and control applications.

  17. Compact pulse width modulation circuitry for silicon photomultiplier readout.

    Science.gov (United States)

    Bieniosek, M F; Olcott, P D; Levin, C S

    2013-08-07

    The adoption of solid-state photodetectors for positron emission tomography (PET) system design and the interest in 3D interaction information from PET detectors has lead to an increasing number of readout channels in PET systems. To handle these additional readout channels, PET readout electronics should be simplified to reduce the power consumption, cost, and size of the electronics for a single channel. Pulse-width modulation (PWM), where detector pulses are converted to digital pulses with width proportional to the detected photon energy, promises to simplify PET readout by converting the signals to digital form at the beginning of the processing chain, and allowing a single time-to-digital converter to perform the data acquisition for many channels rather than routing many analogue channels and digitizing in the back end. Integrator based PWM systems, also known as charge-to-time converters (QTCs), are especially compact, reducing the front-end electronics to an op-amp integrator with a resistor discharge, and a comparator. QTCs, however, have a long dead-time during which dark count noise is integrated, reducing the output signal-to-noise ratio. This work presents a QTC based PWM circuit with a gated integrator that shows performance improvements over existing QTC based PWM. By opening and closing an analogue switch on the input of the integrator, the circuit can be controlled to integrate only the portions of the signal with a high signal-to-noise ratio. It also allows for multiplexing different detectors into the same PWM circuit while avoiding uncorrelated noise propagation between photodetector channels. Four gated integrator PWM circuits were built to readout the spatial channels of two position sensitive solid-state photomultiplier (PS-SSPM). Results show a 4 × 4 array 0.9 mm × 0.9 mm × 15 mm of LYSO crystals being identified on the 5 mm × 5 mm PS-SSPM at room temperature with no degradation for twofold multiplexing. In principle, much larger

  18. Pulse Width Modulation Applied to Olfactory Stimulation for Intensity Tuning.

    Science.gov (United States)

    Andrieu, Patrice; Billot, Pierre-Édouard; Millot, Jean-Louis; Gharbi, Tijani

    2015-01-01

    For most olfactometers described in the literature, adjusting olfactory stimulation intensity involves modifying the dilution of the odorant in a neutral solution (water, mineral, oil, etc.), the dilution of the odorant air in neutral airflow, or the surface of the odorant in contact with airflow. But, for most of these above-mentioned devices, manual intervention is necessary for adjusting concentration. We present in this article a method of controlling odorant concentration via a computer which can be implemented on even the most dynamic olfactometers. We used Pulse Width Modulation (PWM), a technique commonly used in electronic or electrical engineering, and we have applied it to odor delivery. PWM, when applied to odor delivery, comprises an alternative presentation of odorant air and clean air at a high frequency. The cycle period (odor presentation and rest) is 200 ms. In order to modify odorant concentration, the ratio between the odorant period and clean air presentation during a cycle is modified. This ratio is named duty cycle. Gas chromatography measurements show that this method offers a range of mixing factors from 33% to 100% (continuous presentation of odor). Proof of principle is provided via a psychophysical experiment. Three odors (isoamyl acetate, butanol and pyridine) were presented to twenty subjects. Each odor was delivered three times with five values of duty cycles. After each stimulation, the subjects were asked to estimate the intensity of the stimulus on a 10 point scale, ranging from 0 (undetectable) to 9 (very strong). Results show a main effect of the duty cycles on the intensity ratings for all tested odors.

  19. Pulse Width Modulation Applied to Olfactory Stimulation for Intensity Tuning.

    Directory of Open Access Journals (Sweden)

    Patrice Andrieu

    Full Text Available For most olfactometers described in the literature, adjusting olfactory stimulation intensity involves modifying the dilution of the odorant in a neutral solution (water, mineral, oil, etc., the dilution of the odorant air in neutral airflow, or the surface of the odorant in contact with airflow. But, for most of these above-mentioned devices, manual intervention is necessary for adjusting concentration. We present in this article a method of controlling odorant concentration via a computer which can be implemented on even the most dynamic olfactometers. We used Pulse Width Modulation (PWM, a technique commonly used in electronic or electrical engineering, and we have applied it to odor delivery. PWM, when applied to odor delivery, comprises an alternative presentation of odorant air and clean air at a high frequency. The cycle period (odor presentation and rest is 200 ms. In order to modify odorant concentration, the ratio between the odorant period and clean air presentation during a cycle is modified. This ratio is named duty cycle. Gas chromatography measurements show that this method offers a range of mixing factors from 33% to 100% (continuous presentation of odor. Proof of principle is provided via a psychophysical experiment. Three odors (isoamyl acetate, butanol and pyridine were presented to twenty subjects. Each odor was delivered three times with five values of duty cycles. After each stimulation, the subjects were asked to estimate the intensity of the stimulus on a 10 point scale, ranging from 0 (undetectable to 9 (very strong. Results show a main effect of the duty cycles on the intensity ratings for all tested odors.

  20. utility interfaced pulse-width modulation of solar fed voltage source

    African Journals Online (AJOL)

    utility interface, single phase full bridge inverter, boost converter, pulse-width modulation, fixed-band hysteresis current controller, current ... tem include reducing air pollution caused by the use of fossil fuel, minimization of global ... sil fuel and degradation level of ozone layer in the atmosphere caused by dependency on ...

  1. Suppression of high-frequency perturbations in pulse-width modulation

    DEFF Research Database (Denmark)

    2008-01-01

    A method suppresses high-frequency perturbations in a pulse-width modulated signal. The pulse-width modulation may superpose a carrier signal onto an input signal having a predetermined modulation frequency. The carrier signals may be phase-shifted. The resulting modulated signals may...

  2. Suppression of high-frequency perturbations in pulse-width modulation

    OpenAIRE

    Knott, Arnold

    2008-01-01

    A method suppresses high-frequency perturbations in a pulse-width modulated signal. The pulse-width modulation may superpose a carrier signal onto an input signal having a predetermined modulation frequency. The carrier signals may be phase-shifted. The resulting modulated signals may then be filtered and combined.

  3. Self-Oscillating Fluxgate Current Sensor with Pulse Width Modulated Feedback

    OpenAIRE

    Milan Ponjavić; Radivoje Đurić

    2010-01-01

    A self-oscillating fluxgate current sensor with pulse-width modulated feedback is discussed in the paper. The current feedback creates additional dissipation in the circuit which could be reduced by applying the method of pulse-width modulation. For simplicity, the pulse-width modulator is realized as a selfoscillating structure whosefrequency is adjusted by means of the hysteresis of a regenerative comparator, and the feedback is realized with no additional winding.

  4. A Statistical Approach for Obtaining the Controlled Woven Fabric Width

    Directory of Open Access Journals (Sweden)

    Shaker Khubab

    2015-12-01

    Full Text Available A common problem faced in fabric manufacturing is the production of inconsistent fabric width on shuttleless looms in spite of the same fabric specifications. Weft-wise crimp controls the fabric width and it depends on a number of factors, including warp tension, temple type, fabric take-up pressing tension and loom working width. The aim of this study is to investigate the effect of these parameters on the fabric width produced. Taguchi’s orthogonal design was used to optimise the weaving parameters for obtaining controlled fabric width. On the basis of signal to noise ratios, it could be concluded that controlled fabric width could be produced using medium temple type and intense take-up pressing tension at relatively lower warp tension and smaller loom working width. The analysis of variance revealed that temple needle size was the most significant factor affecting the fabric width, followed by loom working width and warp tension, whereas take-up pressing tension was least significant of all the factors investigated in the study.

  5. Optimized Pulse Width Modulation for transformerless active-NPC inverters

    DEFF Research Database (Denmark)

    Achilladelis, Nikolaos; Koutroulis, Eftichios; Blaabjerg, Frede

    2014-01-01

    their power semiconductors. In this paper, a new modulation technique is proposed for optimally controlling the power switches employed in transformerless Active-NPC inverters. The design results demonstrate that compared to the existing PWM strategies, using the proposed method results in lower total power......The transformerless DC/AC inverter topologies are employed in Photovoltaic systems in order to improve the power conversion efficiency, power density and cost. The Active-Neutral Point Clamped (Active-NPC) transformerless inverters have the advantage of achieving better thermal balance among...

  6. Measurement of the laser pulse width on the microscope objective plane by modulated autocorrelation method.

    Science.gov (United States)

    Cannone, F; Chirico, G; Baldini, G; Diaspro, A

    2003-05-01

    We report on the construction details of a compact autocorrelator set-up for the measurement of the width of infrared laser pulses at the focal plane of a microscope for two-photon excitation fluorescence imaging. One of the novelties of the set-up, which leads to an improved measurement accuracy, is the use of a modulation technique that is achieved by mounting one of the interferometer mirrors on a loudspeaker driven by a sinusoidal bias at low frequency. A non-linear least-square routine selects only that part of the fluorescence signal that is modulated at the same frequency as the loudspeaker bias. To further increase the accuracy, the laser pulse width is obtained from a series of measurements at different values of the modulation bias. The autocorrelator is a compact single bread-board (10 x 20 cm); it is PC-controlled both for the acquisition and the analysis of the data and can be coupled to different ports of the microscope. The increase in the pulse width measured for three different ports of the microscope is well accounted for by the group velocity dispersion and the glass thickness of the optics found along these paths.

  7. Optimal pulse-width modulation for sinusoidal fringe generation with projector defocusing: comment.

    Science.gov (United States)

    Ayubi, Gastón A; Ferrari, José A

    2011-03-15

    We comment on a recent Letter [Opt. Lett. 35, 4121 (2010)], in which the authors discuss an optimal pulse-width modulation (OPWM) method for sinusoidal fringe generation. We consider that the comparison of the squared binary method (SBM) and the sinusoidal pulse-width modulation (SPWM) method has considerable deficiencies.

  8. Effect of different methods of pulse width modulation on power losses in an induction motor

    Science.gov (United States)

    Gulyaev, Alexander; Fokin, Dmitrii; Shuharev, Sergey; Ten, Evgenii

    2017-10-01

    We consider the calculation of modulation power losses in a system “induction motor–inverter” for various pulse width modulation (PWM) methods of the supply voltage. Presented values of modulation power losses are the result of modeling a system “DC link - two-level three-phase voltage inverter - induction motor - load”. In this study the power losses in a system “induction motor - inverter” are computed, as well as losses caused by higher harmonics of PWM supply voltage, followed by definition of active power consumed by the DC link for a specified value mechanical power on the induction motor shaft. Mechanical power was determined by the rotation speed and the torque on the motor shaft in various quasi-sinusoidal supply voltage PWM modes. These calculations reveal the best coefficient of performance (COP) in a system of a variable frequency drive (VFD) with independent voltage inverter controlled by induction motor PWM.

  9. Analysis of Symmetrical Pulse Width Modulation Strategies for Matrix Converters

    DEFF Research Database (Denmark)

    Larsen, K.B.; Jorgensen, A.H.; Helle, Lars

    2002-01-01

    This paper presents a new and easy way to understand the derivation of the modulation functions for matrix converters. It is shown how the duty cycles can be calculated using techniques known from the back-to-back (B2B) voltage source inverter (VSI), thus making the subject accessible to people...... with prior knowledge in standard drives. A new modulation strategy is presented minimizing harmonic distortion compared to the standard double-sided space vector modulation for matrix converters. An improvement to an existing modulator is also presented where the proposed modification improves the harmonic...... performance. The strategies are compared both analytically and by the use of both simulations and measurements on a 12 kW matrix converter prototype.It is found that the proposed modulator has superior performance compared to modulators with equal switching frequencies and an equal number of switchings....

  10. Laboratory manual for pulse-width modulated DC-DC power converters

    CERN Document Server

    Kazimierczuk, Marian K

    2015-01-01

    Designed to complement a range of power electronics study resources, this unique lab manual helps students to gain a deep understanding of the operation, modeling, analysis, design, and performance of pulse-width modulated (PWM) DC-DC power converters.  Exercises focus on three essential areas of power electronics: open-loop power stages; small-signal modeling, design of feedback loops and PWM DC-DC converter control schemes; and semiconductor devices such as silicon, silicon carbide and gallium nitride. Meeting the standards required by industrial employers, the lab manual combines program

  11. Pulse-width modulated external resistance increases the microbial fuel cell power output.

    Science.gov (United States)

    Coronado, J; Perrier, M; Tartakovsky, B

    2013-11-01

    This study describes MFC operation with a pulse-width modulated connection of the external resistor (R-PWM mode) at low and high frequencies. Analysis of the output voltage profiles acquired during R-PWM tests showed the presence of slow and fast dynamic components, which can be described by a simple equivalent circuit model suitable for process control applications. At operating frequencies above 100 Hz a noticeable improvement in MFC performance was observed with the power output increase of 22-43% as compared to MFC operation with a constant external resistance. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

  12. A comparative analysis of different pulse width modulation methods for low cost induction motor drives

    Energy Technology Data Exchange (ETDEWEB)

    Kojabadi, Hossein Madadi, E-mail: hmadadi64@yahoo.c [Department of Electrical Engineering, Sahand University of Technology, Tabriz 51335/1996 (Iran, Islamic Republic of)

    2011-01-15

    Many pulse width modulation (PWM) methods for low cost induction motor (IM) drives have been proposed to design high performance industrial motor drives. However most of them have unbalance three phase output currents due to the dynamic unbalance between the two capacitors. Three different PWM methods, namely; hysteresis current control, sinusoidal pulse width modulation (SPWM) and a novel four switch low cost IM drives are discussed in this paper. The second one, namely SPWM, is based on the generalization of existing methods, and the third one is the proposed method, which is an improvement over the two other methods. Although all three schemes can provide three output currents with 120{sup o} phase shift for IM drive, the proposed technique is superior to others in achieving more precise current control with minimum distortion and harmonic noise, and at the same time, negligible unbalance in output currents. Simulation and experimental results of hysteresis current control, SPWM method and new proposed method is presented in order to confirm the effectiveness of proposed method in providing balanced three phase output currents and voltages.

  13. Total Ionizing Dose Test Report for the UC1823A Pulse Width Modulator

    Science.gov (United States)

    Chen, Dakai; Forney, James

    2017-01-01

    The purpose of this study is to examine the total ionizing dose susceptibility for the UC1823A pulse width modulator manufactured by Texas Instruments, Inc. The part is suspected to be vulnerable to enhanced low dose rate sensitivity (ELDRS).

  14. Enhancement of mosquito trapping efficiency by using pulse width modulated light emitting diodes

    Science.gov (United States)

    Liu, Yu-Nan; Liu, Yu-Jen; Chen, Yi-Chian; Ma, Hsin-Yi; Lee, Hsiao-Yi

    2017-01-01

    In this study, a light-driving bug zapper is presented for well controlling the diseases brought by insects, such as mosquitoes. In order to have the device efficient to trap the insect pests in off-grid areas, pulse width modulated light emitting diodes (PWM-LED) combined with a solar power module are proposed and implemented. With specific PWM electric signals to drive the LED, it is found that no matter what the ability of catching insects or the consumed power efficiency can be enhanced thus. It is demonstrated that 40% of the UV LED consumed power and 25.9% of the total load power consumption can be saved, and the trapped mosquitoes are about 250% increased when the PWM method is applied in the bug zapper experiments.

  15. Method and apparatus for improved efficiency in a pulse-width-modulated alternating current motor drive

    Science.gov (United States)

    Konrad, Charles E.; Boothe, Richard W.

    1994-01-01

    A scheme for optimizing the efficiency of an AC motor drive operated in a pulse-width-modulated mode provides that the modulation frequency of the power furnished to the motor is a function of commanded motor torque and is higher at lower torque requirements than at higher torque requirements.

  16. Reconfigurable optofluidic switch for generation of optical pulse width modulation based on tunable reflective interface.

    Science.gov (United States)

    Mansuori, M; Zareei, G H; Hashemi, H

    2015-10-01

    We present a numerical method for generation of optical pulse width modulation (PWM) based on tunable reflective interface by using a microfluidic droplet. We demonstrate a single layer, planar, optofluidic PWM switch that is driven by excited alternating microbubbles. The main parameters of generation of this PWM such as frequency and speed of switching can be controlled by the mass flow rates of input fluids, and the shape of plug or droplet. Advantages of this design are the reconfigurability in design and the easy control of the switching parameters. The validation of the proposed design is carried out by employing the finite element method (FEM) for the mechanical simulation and the finite-difference time-domain (FDTD) for the optical simulation.

  17. Comparison of the squared binary, sinusoidal pulse width modulation, and optimal pulse width modulation methods for three-dimensional shape measurement with projector defocusing.

    Science.gov (United States)

    Wang, Yajun; Zhang, Song

    2012-03-01

    This paper presents a comparative study on three sinusoidal fringe pattern generation techniques with projector defocusing: the squared binary defocusing method (SBM), the sinusoidal pulse width modulation (SPWM) technique, and the optimal pulse width modulation (OPWM) technique. Because the phase error will directly affect the measurement accuracy, the comparisons are all performed in the phase domain. We found that the OPWM almost always performs the best, and SPWM outperforms SBM to a great extent, while these three methods generate similar results under certain conditions. We will briefly explain the principle of each technique, describe the optimization procedures for each technique, and finally compare their performances through simulations and experiments. © 2012 Optical Society of America

  18. Pulse-width-modulated amplifier drives for machine tools

    Energy Technology Data Exchange (ETDEWEB)

    Barkman, W.E.

    1979-11-01

    The function of a dc servo controller is to convert command and feedback information into an error signal that is used to drive a dc motor. To accomplish this, the controller utilizes a summing technique that compares an input-command voltage with a feedback voltage from an external transducer. The resultant error signal is applied to a linear or a switching servo amplifier. While the output of the linear amplifier may have the ideal representation of the desired drive signal, it does result in substantial power dissipation within the amplifier and requires forced-air cooling for power ratings above 100 to 200 W. The switching amplifier avoids this problem by rapidly changing the state of its output stage from a conducting to a nonconducting condition, thereby minimizing the operation of the output stage in the high power-dissipation region. The design and operation of the amplifier drive are described. (TFD)

  19. Equalization of Skin Effect Loss Dominated Channels using Pulse-Width Modulation (PWM) Pre-Emphasis

    NARCIS (Netherlands)

    Schrader, J.H.R.; Klumperink, Eric A.M.; Visschers, J.L.; Nauta, Bram

    A digital transmitter pre-emphasis technique is presented that is based on pulse-width modulation, instead of finite impulse response (FIR) filtering. The technique fits well to future high-speed low-voltage CMOS processes. A 0.13μm CMOS transmitter achieves more than 5Gb/s (2-PAM) over 25m of

  20. Space Vector Pulse Width Modulation of a Multi-Level Diode ...

    African Journals Online (AJOL)

    Space Vector Pulse Width Modulation of a Multi-Level Diode Clamped Converter with Experimental Verification. ... This paper used generic on-time application method to realize the application time for the zero vector and two adjacent active vectors in determining the switching process of the multilevel DCC, quite unlike the ...

  1. A two-level voltage source inverter with differentially sinusoidal pulse width modulation used in the interconnection system of a wind turbine generator

    Directory of Open Access Journals (Sweden)

    Alexandros C. Charalampidis

    2014-10-01

    Full Text Available This study analyses an interconnection system based on differentially sinusoidal pulse width modulation, used for the interconnection to the grid of a variable speed wind turbine. The modulation technique used provides specific advantages in comparison with the commonly used sinusoidal pulse width modulation (SPWM technique, such as lower DC bus voltage requirements, smaller switching losses for the same switching frequency as well as less higher harmonic content in the voltage waveforms produced. The respective control system is also described in detail. Thus this study provides a guide enabling the design of any interconnection system based on this modulation technique.

  2. Pulse width Modulation Command Systems Used for the Optimization of Three Phase Inverters

    Directory of Open Access Journals (Sweden)

    LUCANU, M.

    2009-02-01

    Full Text Available This paper deals with a novel pulse width modulation (PWM switching strategy for a voltage source inverter through carrier modification. The proposed discontinuous sine carrier PWM (DPWM1 method, which uses two modified sine waves, has a better spectral quality and a higher fundamental component. This improved waveform has been derived from the original sine PWM technique through the addition of the 17-percent third-harmonic component to the original sine reference.

  3. ON THE EFFICIENT IMPLEMENTATION OF PULSE-WIDTH MODULATED DIGITAL ANALOG CONVERTERS

    OpenAIRE

    Çini, Uğur

    2017-01-01

    Pulse-Width Modulated Digital-Analog Converter (PWM DAC) is the most popular digital-analog conversion structure in embedded system design. However, there is no explicit formulation existing in the literature for the efficient utilization of PWM DAC implementation regarding to resolution and switching noise considerations. In this paper, PWM frequency selection formulization is given to limit switching noise less than least significant bit in the implemented DAC structure. In addition, to ext...

  4. Current mode pulse width modulation/pulse position modulation based on phase lock loop

    National Research Council Canada - National Science Library

    Pichet Wisartpong; Vorapong Silaphan; Sunee Kurutach; Paramote Wardkein

    2017-01-01

    ... at 2.5 V supply voltage, at center frequency 100 MHz. The linear range of input current can be adjusted from 43 A to 109 A, and the corresponding duty cycle of pulse width output is from 93% to 16...

  5. Jitter model and signal processing techniques for pulse width modulation optical recording

    Science.gov (United States)

    Liu, Max M.-K.

    1991-01-01

    A jitter model and signal processing techniques are discussed for data recovery in Pulse Width Modulation (PWM) optical recording. In PWM, information is stored through modulating sizes of sequential marks alternating in magnetic polarization or in material structure. Jitter, defined as the deviation from the original mark size in the time domain, will result in error detection if it is excessively large. A new approach is taken in data recovery by first using a high speed counter clock to convert time marks to amplitude marks, and signal processing techniques are used to minimize jitter according to the jitter model. The signal processing techniques include motor speed and intersymbol interference equalization, differential and additive detection, and differential and additive modulation.

  6. Electrotactile Display with Real-Time Impedance Feedback Using Pulse Width Modulation.

    Science.gov (United States)

    Kajimoto, H

    2012-01-01

    An electrotactile display is a tactile interface composed of skin surface electrodes. The use of such a device is limited by the variability of the elicited sensation. One possible solution to this problem is to monitor skin electrical impedance. Previous studies revealed a correlation between impedance and threshold, but did not construct real-time feedback loops. In this study, an electrotactile display was constructed using a 1.45 μs feedback loop. Real-time pulse width modulation was proposed, and the relationship between skin resistance and absolute threshold was measured to find a function for determining a suitable pulse width from skin resistance. An evaluation experiment revealed that the proposed algorithm suppressed spatial variation and reduced temporal change.

  7. Pulse-Width Modulation of Optogenetic Photo-Stimulation Intensity for Application to Full-Implantable Light Sources.

    Science.gov (United States)

    Chen, Fu-Yu Beverly; Budgett, David M; Sun, Yuhui; Malpas, Simon; McCormick, Daniel; Freestone, Peter S

    2017-02-01

    Optogenetics allows control of neuronal activity with unprecedented spatiotemporal precision, and has enabled both significant advances in neuroscience and promising clinical prospects for some neurological, cardiac, and sensory disorders. The ability to chronically stimulate light-sensitive excitable cells is crucial for developing useful research tools and viable long-term treatment strategies. Popular optogenetic stimulation devices often rely on bench-top light-sources tethered via an optical fibre to the research animal, or significant componentry protruding externally from animal. These approaches are prone to infection, vulnerable to damage and restrict the experimental approaches that can be conducted. An ideal optogenetic stimulator would be contained entirely within the animal and provide precisely controlled optical output. However, existing prototypes of fully implantable devices rely on amplitude tuning of wireless power, which can vary strongly with environmental conditions. Here we show that pulse-width modulation (PWM) of the intensity of a light-emitting diode (LED) can enable control of photo-stimulation intensity equivalent to direct amplitude modulation. This result has significant implications for fully implantable light delivery tools, as PWM can be implemented with simple and miniaturized circuit architectures. We have modified a telemeter device previously developed by our group to include a small form-factor LED capable of generating sufficient optical power with manageable electrical power requirements and minimal heat generation. We have tested key device components in an in vitro mouse brain slice preparation and shown that pulse-width-modulation is an alternative method to modulate photo-stimulation intensity using a miniature circuit and providing easy control.

  8. Double-Carrier Phase-Disposition Pulse Width Modulation Method for Modular Multilevel Converters

    DEFF Research Database (Denmark)

    Zhou, Fayun; Luo, An; Li, Yan

    2017-01-01

    Modular multilevel converters (MMCs) have become one of the most attractive topologies for high-voltage and high-power applications. A double-carrier phase disposition pulse width modulation (DCPDPWM) method for MMCs is proposed in this paper. Only double triangular carriers with displacement angle...... are needed for DCPDPWM, one carrier for the upper arm and the other for the lower arm. Then, the theoretical analysis of DCPDPWM for MMCs is presented by using a double Fourier integral analysis method, and the Fourier series expression of phase voltage, line-to-line voltage and circulating current...

  9. Superfast multifrequency phase-shifting technique with optimal pulse width modulation.

    Science.gov (United States)

    Wang, Yajun; Zhang, Song

    2011-03-14

    The technique of generating sinusoidal fringe patterns by defocusing squared binary structured ones has numerous merits for high-speed three-dimensional (3D) shape measurement. However, it is challenging for this method to realize a multifrequency phase-shifting (MFPS) algorithm because it is difficult to simultaneously generate high-quality sinusoidal fringe patterns with different periods. This paper proposes to realize an MFPS algorithm utilizing an optimal pulse width modulation (OPWM) technique that can selectively eliminate high-order harmonics of squared binary patterns. We successfully develop a 556 Hz system utilizing a three-frequency algorithm for simultaneously measuring multiple objects.

  10. DC link current simulation of voltage source inverter with random space vector pulse width modulation

    Directory of Open Access Journals (Sweden)

    Chen Guoqiang

    2016-01-01

    Full Text Available Aiming at analysis complexity, a simulation model is built and presented to analyze and demonstrate the characteristics of the direct current (DC link current of the three-phase two-level inverter with the random space vector pulse width modulation (SVPWM strategy. The developing procedure and key subsystems of the simulation model are given in detail. Several experiments are done using the simulation model. The results verify the efficiency and convenience of the simulation model and show that the random SVPWM scheme, especially the random switching frequency scheme, can efficiently suppress the harmonic peaks of the DC link current.

  11. Space Vector Pulse Width Modulation Strategy for Single-Phase Three-Level CIC T-source Inverter

    DEFF Research Database (Denmark)

    Shults, Tatiana E.; Husev, Oleksandr O.; Blaabjerg, Frede

    2016-01-01

    This paper presents a novel space vector pulse-width modulation strategy for a single-phase three-level buck-boost inverter based on an impedance-source network. The case study system is based on T-source inverter with continuous input current. To demonstrate the improved performance...... of the inverter, the strategy was compared the traditional pulse-width modulation. It is shown that the approach proposed has fewer switching states and does not suffer from neutral point misbalance....

  12. Pulse width modulation electro-acupuncture on cardiovascular remodeling and plasma nitric oxide in spontaneously hypertensive rats.

    Science.gov (United States)

    Xiong, Xuan; You, Chao; Feng, Qiu-Chao; Yin, Ting; Chen, Zhong-Ben; Ball, Patrick; Wang, Le-Xin

    2011-01-01

    This study was designed to investigate the effect of pulse width modulation electro-acupuncture (PWM-EA) on cardiovascular remodeling and nitric oxide (NO) in spontaneously hypertensive rats (SHR). Thirty-four male SHR were randomly divided into control, captopril, and two PWM-EA groups, which were treated with 350 Hz (SHR-350 Hz) and whole audio bandwith electro-acupuncture (SHR-WAB group) respectively, on the ST 36 point located on the outside of the hind leg. Systolic blood pressure (BP), plasma and myocardial NO were measured. Histological studies were also performed on the aortic wall and the left ventricle. The BP in the SHR-350 Hz, SHR-WAB and the captopril groups was lower than in the control group following the treatment (P .05). The plasma and myocardium NO levels were elevated in the captopril and the SHR-350 Hz group (P pulse width modulation electro-acupuncture on the ST 36 point prevents the progression of hypertension and diminishes the cardiovascular remodeling in SHR. It also elevates plasma and cardiac NO in this animal model.

  13. Feedforward Compensation of Harmonic Distortion Produced by Pulse Width Modulation For Full-digital Audio Amplifier

    Science.gov (United States)

    Yoneya, Akihiko; Watanabe, Akira

    The full-digital audio amplifiers are advantageous with the points of its high power efficiency and its possibility of high fidelity due to the digital signal processing. With the full-digital amplifier, class-D amplifiers are used to drive the load with PWM signals produced from the source signal. Unfortunately, the signals are distorted when the PCM signals are converted to the PWM signals because the pulse-width modulation is a nonlinear conversion from the viewpoint of transient responses. This paper proposes a way to compensate the distortion caused by the pulse-width modulation. A feedforward compensation approach is used because of the simplicity of implementation. The distortion components are estimated with the source signals and its time-derivative signals and used to cancel out them by subtracting them from the source signals. A numerical example with two-tone test is performed to show the effectiveness of the proposed method. The distortion compensation scheme used here may be applicative to other applications.

  14. Current mode pulse width modulation/pulse position modulation based on phase lock loop

    Science.gov (United States)

    Wisartpong, Pichet; Silaphan, Vorapong; Kurutach, Sunee; Wardkein, Paramote

    2017-05-01

    In this paper, the fully integrated CMOS current mode PLL with current input injects at the place of input or output of the loop filter without summing amplifier circuit. It functions as PPM and PWM circuit is present. In addition, its frequency response is an analysis which electronic tuning BPF and LPF are obtained. The proposed circuit has been designed with 0.18 μm CMOS technology. The simulation results of this circuit can be operated at 2.5 V supply voltage, at center frequency 100 MHz. The linear range of input current can be adjusted from 43 μA to 109 μA, and the corresponding duty cycle of pulse width output is from 93% to 16% and the normalized pulse position is from 0.93 to 0.16. The power dissipation of this circuit is 4.68 mW with the total chip area is 28 μm × 60 μm.

  15. Harmonic Spectrum of Output Voltage for Space Vector Pulse Width Modulated Ultra Sparse Matrix Converter

    Directory of Open Access Journals (Sweden)

    Tingna Shi

    2018-02-01

    Full Text Available In a matrix converter, the frequencies of output voltage harmonics are related to the frequencies of input, output, and carrier signals, which are independent of each other. This nature may cause an inaccurate harmonic spectrum when using conventional analytical methods, such as fast Fourier transform (FFT and the double Fourier analysis. Based on triple Fourier series, this paper proposes a method to pinpoint harmonic components of output voltages of an ultra sparse matrix converter (USMC under space vector pulse width modulation (SVPWM strategy. Amplitudes and frequencies of harmonic components are determined precisely for the first time, and the distribution pattern of harmonics can be observed directly from the analytical results. The conclusions drawn in this paper may contribute to the analysis of harmonic characteristics and serve as a reference for the harmonic suppression of USMC. Besides, the proposed method is also applicable to other types of matrix converters.

  16. Solution of the pulse width modulation problem using orthogonal polynomials and Korteweg-de Vries equations.

    Science.gov (United States)

    Chudnovsky, D V; Chudnovsky, G V

    1999-10-26

    The mathematical underpinning of the pulse width modulation (PWM) technique lies in the attempt to represent "accurately" harmonic waveforms using only square forms of a fixed height. The accuracy can be measured using many norms, but the quality of the approximation of the analog signal (a harmonic form) by a digital one (simple pulses of a fixed high voltage level) requires the elimination of high order harmonics in the error term. The most important practical problem is in "accurate" reproduction of sine-wave using the same number of pulses as the number of high harmonics eliminated. We describe in this paper a complete solution of the PWM problem using Pade approximations, orthogonal polynomials, and solitons. The main result of the paper is the characterization of discrete pulses answering the general PWM problem in terms of the manifold of all rational solutions to Korteweg-de Vries equations.

  17. Pulse-width modulation in defocused three-dimensional fringe projection.

    Science.gov (United States)

    Ayubi, Gastón A; Ayubi, Jaime A; Di Martino, J Matías; Ferrari, José A

    2010-11-01

    Shape measurements by fringe projection methods require high-quality sinusoidal fringes. We present a sinusoidal fringe generation technique that utilizes slightly defocused binary fringe projection. The proposed method is a spatial version of the well-known pulse-width modulation (PWM) technique of electrical engineering. PWM is easy to implement using off-the-shelf projectors, and it allows us to overcome the gamma problem (i.e., the nonlinear projector response) in the output light intensity. We will demonstrate that, with a small defocusing level--lower than with other techniques proposed in the literature--a high-quality sinusoidal pattern is obtained. Validation experiments using a commercial video projector are presented.

  18. Note: Investigation of a null measurement of optical absorbance using a pulse width modulated light-emitting diode.

    Science.gov (United States)

    Rusak, David A; Kawka, Ernest A; Trexler, E Brady

    2010-01-01

    We examined the possibility of making a null measurement of optical absorbance by using pulse-width modulation to control the intensity of a light-emitting diode (LED). This type of measurement is intriguing because the instrumental sources of noise are different from those in the traditional absorbance measurement. Our experiment employed phototransistor detectors and a RC integrator to measure the amount of light being transmitted. However, instead of measuring the ratio of the detector voltages for a blank and sample, we measured the ratio of the LED duty cycles required to give the same detector voltage for a blank and a sample. Using this method, it is presumed that the same amount of light reaches the detector during measurement of the blank and sample.

  19. A frequency and pulse-width co-modulation strategy for transcutaneous neuromuscular electrical stimulation based on sEMG time-domain features

    Science.gov (United States)

    Zhou, Yu-Xuan; Wang, Hai-Peng; Bao, Xue-Liang; Lü, Xiao-Ying; Wang, Zhi-Gong

    2016-02-01

    Objective. Surface electromyography (sEMG) is often used as a control signal in neuromuscular electrical stimulation (NMES) systems to enhance the voluntary control and proprioceptive sensory feedback of paralyzed patients. Most sEMG-controlled NMES systems use the envelope of the sEMG signal to modulate the stimulation intensity (current amplitude or pulse width) with a constant frequency. The aims of this study were to develop a strategy that co-modulates frequency and pulse width based on features of the sEMG signal and to investigate the torque-reproduction performance and the level of fatigue resistance achieved with our strategy. Approach. We examined the relationships between wrist torque and two stimulation parameters (frequency and pulse width) and between wrist torque and two sEMG time-domain features (mean absolute value (MAV) and number of slope sign changes (NSS)) in eight healthy volunteers. By using wrist torque as an intermediate variable, customized and generalized transfer functions were constructed to convert the two features of the sEMG signal into the two stimulation parameters, thereby establishing a MAV/NSS dual-coding (MNDC) algorithm. Wrist torque reproduction performance was assessed by comparing the torque generated by the algorithms with that originally recorded during voluntary contractions. Muscle fatigue was assessed by measuring the decline percentage of the peak torque and by comparing the torque time integral of the response to test stimulation trains before and after fatigue sessions. Main Results. The MNDC approach could produce a wrist torque that closely matched the voluntary wrist torque. In addition, a smaller decay in the wrist torque was observed after the MNDC-coded fatigue stimulation was applied than after stimulation using pulse-width modulation alone. Significance. Compared with pulse-width modulation stimulation strategies that are based on sEMG detection, the MNDC strategy is more effective for both voluntary muscle

  20. A frequency and pulse-width co-modulation strategy for transcutaneous neuromuscular electrical stimulation based on sEMG time-domain features.

    Science.gov (United States)

    Zhou, Yu-Xuan; Wang, Hai-Peng; Bao, Xue-Liang; Lü, Xiao-Ying; Wang, Zhi-Gong

    2016-02-01

    Surface electromyography (sEMG) is often used as a control signal in neuromuscular electrical stimulation (NMES) systems to enhance the voluntary control and proprioceptive sensory feedback of paralyzed patients. Most sEMG-controlled NMES systems use the envelope of the sEMG signal to modulate the stimulation intensity (current amplitude or pulse width) with a constant frequency. The aims of this study were to develop a strategy that co-modulates frequency and pulse width based on features of the sEMG signal and to investigate the torque-reproduction performance and the level of fatigue resistance achieved with our strategy. We examined the relationships between wrist torque and two stimulation parameters (frequency and pulse width) and between wrist torque and two sEMG time-domain features (mean absolute value (MAV) and number of slope sign changes (NSS)) in eight healthy volunteers. By using wrist torque as an intermediate variable, customized and generalized transfer functions were constructed to convert the two features of the sEMG signal into the two stimulation parameters, thereby establishing a MAV/NSS dual-coding (MNDC) algorithm. Wrist torque reproduction performance was assessed by comparing the torque generated by the algorithms with that originally recorded during voluntary contractions. Muscle fatigue was assessed by measuring the decline percentage of the peak torque and by comparing the torque time integral of the response to test stimulation trains before and after fatigue sessions. The MNDC approach could produce a wrist torque that closely matched the voluntary wrist torque. In addition, a smaller decay in the wrist torque was observed after the MNDC-coded fatigue stimulation was applied than after stimulation using pulse-width modulation alone. Compared with pulse-width modulation stimulation strategies that are based on sEMG detection, the MNDC strategy is more effective for both voluntary muscle force reproduction and muscle fatigue reduction.

  1. Data acquisition electronics for gamma ray emission tomography using width-modulated leading-edge discriminators

    Energy Technology Data Exchange (ETDEWEB)

    Lage, E; Tapias, G; Villena, J; Desco, M; Vaquero, J J, E-mail: desco@mce.hggm.e [Unidad de Medicina y CirugIa Experimental, Hospital General Universitario Gregorio Maranon, Madrid (Spain)

    2010-08-07

    We present a new high-performance and low-cost approach for implementing radiation detection acquisition systems. The basic elements used are charge-integrating ADCs and a set of components encapsulated in an HDL (hardware definition language) library which makes it possible to implement several acquisition tasks such as time pickoff and coincidence detection using a new and simple trigger technique that we name WMLET (width-modulated leading-edge timing). As proof of concept, a 32-channel hybrid PET/SPECT acquisition system based on these elements was developed and tested. This demonstrator consists of a master module responsible for the generation and distribution of trigger signals, 2 x 16-channel ADC cards (12-bit resolution) for data digitization and a 32-bit digital I/O PCI card for handling data transmission to a personal computer. System characteristics such as linearity, maximum transmission rates or timing resolution in coincidence mode were evaluated with test and real detector signals. Imaging capabilities of the prototype were also evaluated using different detector configurations. The performance tests showed that this implementation is able to handle data rates in excess of 600k events s{sup -1} when acquiring simultaneously 32 channels (96-byte events). ADC channel linearity is >98.5% in energy quantification. Time resolution in PET mode for the tested configurations ranges from 3.64 ns FWHM to 7.88 ns FWHM when signals from LYSO-based detectors are used. The measured energy resolution matched the expected values for the detectors evaluated and single elements of crystal matrices can be neatly separated in the acquired flood histograms.

  2. SWITCH MODE PULSE WIDTH MODULATED DC-DC CONVERTER WITH MULTIPLE POWER TRANSFORMERS

    DEFF Research Database (Denmark)

    2009-01-01

    A switch mode pulse width modulated DC-DC power converter comprises at least one first electronic circuit on a input side (1) and a second electronic circuit on a output side (2). The input side (1) and the output side (2) are coupled via at least two power transformers (T1, T2). Each power...... transformer (T1, T2) comprises a first winding (T1a, T2a) arranged in a input side converter stage (3, 4) on the input side (1) and a second winding (T1 b, T2b) arranged in a output side converter stage (5) on the output side (2), and each of the windings (T1a, T1 b, T2a, T2b) has a first end and a second end....... The first electronic circuit comprises terminals (AO, A1) for connecting a source or a load, at least one energy storage inductor (L) coupled in series with at least one of the first windings (T1a, T2a) of the power transformers (T1, T2), and for each power transformer (T1, T2), an arrangement of switches...

  3. Using pulse width modulation for wireless transmission of neural signals in multichannel neural recording systems.

    Science.gov (United States)

    Yin, Ming; Ghovanloo, Maysam

    2009-08-01

    We have used a well-known technique in wireless communication, pulse width modulation (PWM) of time division multiplexed (TDM) signals, within the architecture of a novel wireless integrated neural recording (WINeR) system. We have evaluated the performance of the PWM-based architecture and indicated its accuracy and potential sources of error through detailed theoretical analysis, simulations, and measurements on a setup consisting of a 15-channel WINeR prototype as the transmitter and two types of receivers; an Agilent 89600 vector signal analyzer and a custom wideband receiver, with 36 and 75 MHz of maximum bandwidth, respectively. Furthermore, we present simulation results from a realistic MATLAB-Simulink model of the entire WINeR system to observe the system behavior in response to changes in various parameters. We have concluded that the 15-ch WINeR prototype, which is fabricated in a 0.5- mum standard CMOS process and consumes 4.5 mW from +/-1.5 V supplies, can acquire and wirelessly transmit up to 320 k-samples/s to a 75-MHz receiver with 8.4 bits of resolution, which is equivalent to a wireless data rate of approximately 2.56 Mb/s.

  4. Optimized pulse width modulation pattern strategy for three-dimensional profilometry with projector defocusing.

    Science.gov (United States)

    Zuo, Chao; Chen, Qian; Feng, Shijie; Feng, Fangxiaoyu; Gu, Guohua; Sui, Xiubao

    2012-07-01

    Three-dimensional profilometry by sinusoidal fringe projection using phase-shifting algorithms is usually distorted by the nonlinear intensity response of commercial video projectors. To overcome this problem, several methods including sinusoidal pulse width modulation (SPWM) were proposed to generate sinusoidal fringe patterns with binary ones by defocusing the project to some certain extent. However, the residual errors are usually nonnegligible for highly accurate measurement fields, especially when the defocusing level is insufficient. In this work, we propose two novel methods to further improve the defocusing technique. We find that by properly optimizing SPWM patterns according to some criteria, and combining SPWM technique with four-step phase-shifting algorithm, the dominant undesired harmonics will have no impact on the phase obtained. We also propose a new sinusoidal fringe generation technique called tripolar SPWM, which can generate ideal sinusoidal fringe patterns with a very small degree of defocusing. Simulations and experiments are presented to verify the performance of these two proposed techniques.

  5. Analysis and Minimization of Output Current Ripple for Discontinuous Pulse-Width Modulation Techniques in Three-Phase Inverters

    Directory of Open Access Journals (Sweden)

    Gabriele Grandi

    2016-05-01

    Full Text Available This paper gives the complete analysis of the output current ripple in three-phase voltage source inverters considering the different discontinuous pulse-width modulation (DPWM strategies. In particular, peak-to-peak current ripple amplitude is analytically evaluated over the fundamental period and compared among the most used DPWMs, including positive and negative clamped (DPWM+ and DPWM−, and the four possible combinations between them, usually named as DPWM0, DPWM1, DPWM2, and DPWM3. The maximum and the average values of peak-to-peak current ripple are estimated, and a simple method to correlate the ripple envelope with the ripple rms is proposed and verified. Furthermore, all the results obtained by DPWMs are compared to the centered pulse-width modulation (CPWM, equivalent to the space vector modulation to identify the optimal pulse-width modulation (PWM strategy as a function of the modulation index, taking into account the different average switching frequency. In this way, the PWM technique providing for the minimum output current ripple is identified over the whole modulation range. The analytical developments and the main results are experimentally verified by current ripple measurements with a three-phase PWM inverter prototype supplying an induction motor load.

  6. The impact of leaf width and plan complexity on DMLC tracking of prostate intensity modulated arc therapy

    DEFF Research Database (Denmark)

    Pommer, Tobias; Falk, Marianne; Poulsen, Per Rugaard

    2013-01-01

    Purpose: Intensity modulated arc therapy (IMAT) is commonly used to treat prostate cancer. The purpose of this study was to evaluate the impact of leaf width and plan complexity on dynamic multileaf collimator (DMLC) tracking for prostate motion management during IMAT treatments.Methods: Prostate...

  7. Pulse width modulated buck-boost five-level current source inverters

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Gao, F.; Loh, P.C.

    2008-01-01

    This paper presents new five-level current source inverters (CSIs) with voltage/current buck-boost capability. Being different from the existing multilevel CSI, the proposed CSIs were first designed to regulate the flowing path of dc input current by controlling two additional active switches......, resulting in the natural balance of input current. For maintaining the normalized volt-sec average unchanged, the alternative phase opposition disposition (APOD) modulation scheme with typical gating signal mapping technique from voltage source inverter (VSI) to CSI can be assumed to control the five......-level buck-boost CSIs. Next by observing the hidden current charging path during inductive charging interval under APOD modulation, it is noted that the buck-boost five-level CSI can then be further modified with lesser active component without degrading output performance. To verify the theoretical findings...

  8. Research on width control of Metal Fused-coating Additive Manufacturing based on active control

    Science.gov (United States)

    Ren, Chuan qi; Wei, Zheng ying; Wang, Xin; Du, Jun; Zhang, Shan; Zhang, Zhitong; Bai, Hao

    2017-12-01

    Given the stability of the shape of the forming layer is one of the key problems that affect the final quality of the sample morphology, taking a study on the forming process and the control method of morphology make a significant difference to metal fused-coating additive manufacturing (MFCAM) in achieving the efficient and stable forming. To improve the quality and precision of the samples of single-layer single pass, a control method of morphology based on active control was established by this paper. The real-time acquisition of image was realized by CCD and the characteristics of morphology of the forming process were simultaneously extracted. Making analysis of the characteristics of the width during the process, the relationship between the relative difference of different frames and moving speed was given. A large number of experiments are used to verify the response speed and accuracy of the system. The results show that the active system can improve the morphology of the sample and the smoothness of the width of the single channel, and increase the uniformity of width by 55.16%.

  9. Increasing the time resolution of a pulse width modulator in a class D power amplifier by using delay lines

    Science.gov (United States)

    Weber, M.; Vennemann, T.; Mathis, W.

    2014-11-01

    In this paper, we present a method to increase the time resolution of a pulse width modulator by using delay lines. The modulator is part of an open loop class D power amplifier, which uses the ZePoC algorithm to code the audio signal which is amplified in the class D power stage. If the time resolution of the pulse width modulator is high enough, ZePoC could also be used to build an high accuracy AC power standard, because of its open loop property. With the presented method the time resolution theoretically could be increased by a factor of 16, which means here the time resolution will be enhanced from 5 ns to 312.5 ps.

  10. Pulse width and height modulation for multi-level resistance in bi-layer TaOx based RRAM

    Science.gov (United States)

    Alamgir, Zahiruddin; Beckmann, Karsten; Holt, Joshua; Cady, Nathaniel C.

    2017-08-01

    Mutli-level switching in resistive memory devices enables a wide range of computational paradigms, including neuromorphic and cognitive computing. To this end, we have developed a bi-layer tantalum oxide based resistive random access memory device using Hf as the oxygen exchange layer. Multiple, discrete resistance levels were achieved by modulating the RESET pulse width and height, ranging from 2 kΩ to several MΩ. For a fixed pulse height, OFF state resistance was found to increase gradually with the increase in the pulse width, whereas for a fixed pulse width, the increase in the pulse height resulted in drastic changes in resistance. Resistive switching in these devices transitioned from Schottky emission in the OFF state to tunneling based conduction in the ON state, based on I-V curve fitting and temperature dependent current measurements. These devices also demonstrated endurance of more than 108 cycles with a satisfactory Roff/Ron ratio and retention greater than 104 s.

  11. Generation of a chirp-free optical pulse train with tunable pulse width based on a polarization modulator and an intensity modulator.

    Science.gov (United States)

    Pan, Shilong; Yao, Jianping

    2009-07-15

    A simple method for the generation of a chirp-free optical pulse train with tunable pulse width using a polarization modulator (PolM) and a zero-chirp intensity modulator (IM) is proposed and demonstrated. In the proposed system, a light wave with its polarization direction oriented at an angle of 45 degrees with respect to the principal axis of the PolM is polarization modulated by a sinusoidal drive signal. An optical polarizer is connected after the PolM to convert the polarization-modulated signals to a pulse train with the main peaks having a narrow pulse width. Then, the main peaks are selected by the IM, leading to the generation of a short optical pulse train with a repetition rate that is identical to or twice the frequency of the sinusoidal drive signal, depending on the dc bias of the IM. The pulse width of the generated pulse is easily tuned by adjusting the phase modulation index of the PolM. An experiment is carried out, and a pulse train with a duty cycle as small as 8.16% is generated.

  12. Controls on channel width in an intermontane valley of the frontal zone of the northwestern Himalaya

    Science.gov (United States)

    Parida, Sukumar; Tandon, S. K.; Singh, Vimal

    2017-02-01

    Channel width is an important parameter of the hydraulic geometry of a river and can be linked to the tectonic, topographic, lithologic, and climatic controls in a particular reach. As such, variations in channel width can be the result of one or many factors acting at a specific location. For the rivers flowing in the intermontane valleys along the frontal Himalaya, active tectonics plays a major role in controlling their geometry by providing the space, energy, and sediment. Dehra Dun is an intermontane valley in the northwestern Himalaya where the rivers have their source in the Lesser Himalaya and Sub-Himalaya; they show remarkable variability in the channel width along their course. In this work, we have attempted to identify and evaluate the relative importance of various controlling factors on the channel width of these drainage systems. We selected 20 streams (six North Flank rivers - NFRs; two Main Axial rivers - MARs; twelve South Flank rivers - SFRs) flowing in the valley. In the hilly stretches, the NFRs flow over the Lesser Himalaya and the SFRs flow over the poorly consolidated upper Siwalik gravelly sediments. Channel width in the mountainous region varies generally from 5 to 30 m. The SFRs that have smaller catchments are relatively wider than the NFRs in the mountainous areas. In the Dun, the width variation is mostly between 50 and 400 m. The NFRs show widening in their middle stretches except for the Tons River, which is wide in its lower stretch. Channels widen as they cross the structural zones (i.e., the Main Boundary Thrust (MBT), the Santaurgarh Thrust (ST), and the Bhauwala Thrust (BT)) as a result of the change in the gradient across the structures. Large sediment supply generated by mass wasting processes from the weak zones (i.e., fault-related zones) and uplifted surfaces make the river transport limited, resulting in the deposition of the sediments. Consequently, channel bed armoring in these gravel-bed rivers protects the channel

  13. Paralleled Phase Shifted Carrier Pulse Width Modulation (PSCPWM) Schemes - A Fundamental Analysis

    DEFF Research Database (Denmark)

    Christensen, Frank Schwartz; Frederiksen, Thomas Mansachs; Nielsen, Karsten

    1999-01-01

    The paper presents a fundamental analysis of modulation schemes and their spectral aspects for a range of powerstage topologies, from a simple 2-level switching leg to more complex multi-level switching topologies. A family of modulation schemes are introduced and the double Fourier series based...

  14. Cenozoic tectonics of Western North America controlled by evolving width of Farallon slab

    NARCIS (Netherlands)

    Schellart, W. P.; Stegman, D. R.; Farrington, R. J.; Freeman, J.A.; Moresi, L.

    2010-01-01

    Subduction of oceanic lithosphere occurs through two modes: subducting plate motion and trench migration. Using a global subduction zone data set and three-dimensional numerical subduction models, we show that slab width (W) controls these modes and the partitioning of subduction between them.

  15. Cenozoic tectonics of western North America controlled by evolving width of Farallon slab.

    Science.gov (United States)

    Schellart, W P; Stegman, D R; Farrington, R J; Freeman, J; Moresi, L

    2010-07-16

    Subduction of oceanic lithosphere occurs through two modes: subducting plate motion and trench migration. Using a global subduction zone data set and three-dimensional numerical subduction models, we show that slab width (W) controls these modes and the partitioning of subduction between them. Subducting plate velocity scales with W(2/3), whereas trench velocity scales with 1/W. These findings explain the Cenozoic slowdown of the Farallon plate and the decrease in subduction partitioning by its decreasing slab width. The change from Sevier-Laramide orogenesis to Basin and Range extension in North America is also explained by slab width; shortening occurred during wide-slab subduction and overriding-plate-driven trench retreat, whereas extension occurred during intermediate to narrow-slab subduction and slab-driven trench retreat.

  16. Pulse-width modulation for small heat pump installations - Phase 4; Pulsbreitenmodulation fuer Kleinwaermepumpenanlagen. Phase 4: Erweiterung der PBM-Regler fuer Kombianlagen

    Energy Technology Data Exchange (ETDEWEB)

    Bianchi, M.; Shafai, E. [Eidgenoessische Technische Hochschule (ETH), Institut fuer Mess- und Regeltechnik, Zuerich (Switzerland); Gabathuler, H.R.; Mayer, H. [Gabathuler AG, Beratende Ingenieure, Diessenhofen (Switzerland)

    2005-07-01

    This final report for the Swiss Federal Office of Energy (SFOE) presents the results of the fourth phase of a project that investigated three types of pulse-width modulation (PWM) controllers that were developed during its first two phases. A third phase monitored the controllers when used in a simulated environment and for a real-life heat pump. The report discusses the fourth phase of the project, in which the controller was further developed and tested using the building emulation developed in the third phase. The functioning of the self-regulating controller and its use of meteorological data is described and the savings to be made in heating costs are discussed.

  17. Modular space-vector pulse-width modulation for nine-switch converters

    DEFF Research Database (Denmark)

    Dehghan, Seyed Mohammad; Amiri, Arash; Mohamadian, Mustafa

    2013-01-01

    Recently, nine-switch inverter (NSI) has been presented as a dual-output inverter with constant frequency (CF) or different frequency (DF) operation modes. However, the CF mode is more interesting because of its lower switching device rating. This study proposes a new space-vector modulation (SVM......) method for the NSI that supports both the CF and DF modes, whereas conventional SVM of NSI can be used only in the DF mode. The proposed SVM can be easily implemented based on the conventional six-switch inverter SVM modules. The performance of the proposed SVM is verified by the simulation...

  18. SEMICONDUCTOR INTEGRATED CIRCUITS: DCM, FSM, dead time and width controllers for a high frequency high efficiency buck DC-DC converter over a wide load range

    Science.gov (United States)

    Changming, Pi; Wei, Yan; Ke, Zhang; Wenhong, Li

    2010-08-01

    This paper presents a width controller, a dead time controller, a discontinuous current mode (DCM) controller and a frequency skipping modulation (FSM) controller for a high frequency high efficiency buck DC-DC converter. To improve the efficiency over a wide load range, especially at high switching frequency, the dead time controller and width controller are applied to enhance the high load efficiency, while the DCM controller and FSM controller are proposed to increase the light load efficiency. The proposed DC-DC converter controllers have been designed and fabricated in the Chartered 0.35 μm CMOS process, and the measured results show that the efficiency of the buck DC-DC converter is above 80% over a wide load current range from 8 to 570 mA, and the peak efficiency is 86% at 10 MHz switching frequency.

  19. DCM, FSM, dead time and width controllers for a high frequency high efficiency buck DC-DC converter over a wide load range

    Energy Technology Data Exchange (ETDEWEB)

    Pi Changming; Yan Wei; Zhang Ke; Li Wenhong, E-mail: wenhongli@fudan.edu.c [State Key Laboratory of ASIC and Systems, Fudan University, Shanghai 201203 (China)

    2010-08-15

    This paper presents a width controller, a dead time controller, a discontinuous current mode (DCM) controller and a frequency skipping modulation (FSM) controller for a high frequency high efficiency buck DC-DC converter. To improve the efficiency over a wide load range, especially at high switching frequency, the dead time controller and width controller are applied to enhance the high load efficiency, while the DCM controller and FSM controller are proposed to increase the light load efficiency. The proposed DC-DC converter controllers have been designed and fabricated in the Chartered 0.35 {mu}m CMOS process, and the measured results show that the efficiency of the buck DC-DC converter is above 80% over a wide load current range from 8 to 570 mA, and the peak efficiency is 86% at 10 MHz switching frequency. (semiconductor integrated circuits)

  20. Breaking Through the Multi-Mesa-Channel Width Limited of Normally Off GaN HEMTs Through Modulation of the Via-Hole-Length

    Science.gov (United States)

    Chien, Cheng-Yen; Wu, Wen-Hsin; You, Yao-Hong; Lin, Jun-Huei; Lee, Chia-Yu; Hsu, Wen-Ching; Kuan, Chieh-Hsiung; Lin, Ray-Ming

    2017-06-01

    We present new normally off GaN high-electron-mobility transistors (HEMTs) that overcome the typical limitations in multi-mesa-channel (MMC) width through modulation of the via-hole-length to regulate the charge neutrality screen effect. We have prepared enhancement-mode (E-mode) GaN HEMTs having widths of up to 300 nm, based on an enhanced surface pinning effect. E-mode GaN HEMTs having MMC structures and widths as well as via-hole-lengths of 100 nm/2 μm and 300 nm/6 μm, respectively, exhibited positive threshold voltages ( V th) of 0.79 and 0.46 V, respectively. The on-resistances of the MMC and via-hole-length structures were lower than those of typical tri-gate nanoribbon GaN HEMTs. In addition, the devices not only achieved the E-mode but also improved the power performance of the GaN HEMTs and effectively mitigated the device thermal effect. We controlled the via-hole-length sidewall surface pinning effect to obtain the E-mode GaN HEMTs. Our findings suggest that via-hole-length normally off GaN HEMTs have great potential for use in next-generation power electronics.

  1. Dosimetric study using different leaf-width MLCs for treatment planning of dynamic conformal arcs and intensity-modulated radiosurgery.

    Science.gov (United States)

    Jin, Jian-Yue; Yin, Fang-Fang; Ryu, Samuel; Ajlouni, Munther; Kim, Jae Ho

    2005-02-01

    This paper systematically studied the dosimetric difference between a 3 mm micro multileaf collimator (MLC), a 5 mm MLC, and a 10 mm MLC for stereotactic radiosurgery using the Brainscan treatment planning system. Thirty-four cases treated with the dynamic conformal arcs technique and 20 cases treated with the intensity modulated radiosurgery/fractionated radiotherapy (IMRS/ IMRT) technique were retrospectively studied. The conformity index, the percentage target coverage, and the dose-volume histogram (DVH) for organs-at-risk (OARs) were used for dosimetric analysis and comparison for different treatment techniques, target volumes, and treatment sites. For the dynamic conformal arcs technique, there were statistically significant differences in the conformity indices between different leaf-width MLCs. The ratio of the conformity indices between different MLCs depended on the target volume. The average conformity index ratios between the 5 mm MLC and the 3 mm MLC were 1.37+/-0.09, 1.12+/-0.04, 1.08+/-0.02 and 1.04+/-0.01, respectively, for patients with the target volume (V) in groups: (1) V 27 CC. The average conformity index ratios between the 10 and 3 mm MLCs were 2.00+/-0.33, 1.45+/-0.09, 1.28+/-0.09, and 1.18+/-0.05 for patients in these four volume groups, respectively. No statistically significant difference was found for the target coverage among different MLCs. For the IMRS/IMRT technique, the average conformity index and target coverage ratios were 1.01+/-0.05 and 1.00+/-0.02, respectively, between the 5 and 3 mm MLCs, and were 1.04+/-0.07 and 0.97+/-0.02, respectively, between the 10 and 3 mm MLCs. The 3 mm MLC showed slightly better overall OAR DVHs than the 5 and 10 mm MLCs, especially for the cranial site with small-volume OARs defined. The results suggest that for the dynamic conformal arcs technique, the narrower leaf-width MLC provides better dose conformity than the wider leaf-width MLCs. This advantage decreases when the target volume increases

  2. Pulse-Width-Modulation of Neutral-Point-Clamped Sparse Matrix Converter

    DEFF Research Database (Denmark)

    Loh, P.C.; Blaabjerg, Frede; Gao, F.

    2007-01-01

    input current and output voltage can be achieved with minimized rectification switching loss, rendering the sparse matrix converter as a competitive choice for interfacing the utility grid to (e.g.) defense facilities that require a different frequency supply. As an improvement, sparse matrix converter......Sparse matrix converter is an alternative "allsemiconductor" energy processor proposed recently for converting an ac source with fixed magnitude and frequency to a variable voltage and frequency supply that can meet the requirements of a particular industry application. In principle, sparse matrix...... converter is constructed by connecting a front-end bi-directional rectification stage to a conventional two-level inversion stage with no bulky capacitive or inductive energy storage connected to their intermediate dc-link. Through proper modulation and compensation of the resulting converter, sinusoidal...

  3. Analysis and Speed Ripple Mitigation of a Space Vector Pulse Width Modulation-Based Permanent Magnet Synchronous Motor with a Particle Swarm Optimization Algorithm

    Directory of Open Access Journals (Sweden)

    Xing Liu

    2016-11-01

    Full Text Available A method is proposed for reducing speed ripple of permanent magnet synchronous motors (PMSMs controlled by space vector pulse width modulation (SVPWM. A flux graph and mathematics are used to analyze the speed ripple characteristics of the PMSM. Analysis indicates that the 6P (P refers to pole pairs of the PMSM time harmonic of rotor mechanical speed is the main harmonic component in the SVPWM control PMSM system. To reduce PMSM speed ripple, harmonics are superposed on a SVPWM reference signal. A particle swarm optimization (PSO algorithm is proposed to determine the optimal phase and multiplier coefficient of the superposed harmonics. The results of a Fourier decomposition and an optimized simulation model verified the accuracy of the analysis as well as the effectiveness of the speed ripple reduction methods, respectively.

  4. Three-dimensional shape profiling by out-of-focus projection of colored pulse width modulation fringe patterns.

    Science.gov (United States)

    Silva, Adriana; Flores, Jorge L; Muñoz, Antonio; Ayubi, Gastón A; Ferrari, José A

    2017-06-20

    Three-dimensional (3D) shape profiling by sinusoidal phase-shifting methods is affected by the non-linearity of the projector. To overcome this problem, the defocusing technique has become an important alternative to generate sinusoidal fringe patterns. The precision of this method depends on the binary pattern used and on the defocusing applied. To improve the defocusing technique, we propose the implementation of a color-based binary fringe patterns. The proposed technique involves the generation of colored pulse width modulation (PWM) fringe patterns, which are generated with different frequencies at the carrier signal. From an adequate selection of these frequencies, the colored PWM fringe patterns will lead to amplitude harmonics lower than the conventional PWM fringe patterns. Hence, the defocusing can decrease, and the 3D shape profiling can be more accurate. Numerical simulations and experimental results are presented as validation.

  5. Effects and Analysis of Minimum Pulse Width Limitation on Adaptive DC Voltage Control of Grid Converters

    DEFF Research Database (Denmark)

    Sun, Bo; Trintis, Ionut; Munk-Nielsen, Stig

    2016-01-01

    This paper presents an adaptive dc-link voltage controller for the purpose of decreasing the operating dc-link voltage in a back-to-back converter system. An outer loop to control the maximum modulation (Mmax) index is added to the conventional dc-link voltage controller, and hence the system can...

  6. Effect of electron cyclotron beam width to neoclassical tearing mode stabilization by minimum seeking control in ITER

    Science.gov (United States)

    Park, Minho; Na, Yong-Su; Seo, Jaemin; Kim, M.; Kim, Kyungjin

    2018-01-01

    We report the effect of the electron cyclotron (EC) beam width on the full suppression time of neoclassical tearing mode (NTM) using the finite difference method (FDM) based minimum seeking controller in ITER. An integrated numerical system is setup for time-dependent simulations of the NTM evolution in ITER by solving the modified Rutherford equation together with the plasma equilibrium, transport, and EC heating and current drive. The calculated magnetic island width and growth rate is converted to the Mirnov diagnostic signal as an input to the controller to mimic the real experiment. In addition, 10% of the noise is enforced to this diagnostic signal to evaluate the robustness of the controller. To test the dependency of the NTM stabilization time on the EC beam width, the EC beam width scan is performed for a perfectly aligned case first, then for cases with the feedback control using the minimum seeking controller. When the EC beam is perfectly aligned, the narrower the EC beam width, the smaller the NTM stabilization time is observed. As the beam width increases, the required EC power increases exponentially. On the other hand, when the minimum seeking controller is applied, NTM stabilization sometimes fails as the EC beam width decreases. This is consistently observed in the simulation with various representations of the noise as well as without the noise in the Mirnov signal. The higher relative misalignment, misalignment divided by the beam width, is found to be the reason for the failure with the narrower beam widths. The EC stabilization effect can be lower for the narrower beam widths than the broader ones even at the same misalignment due to the smaller ECCD at the island O-point. On the other hand, if the EC beam is too wide, the NTM stabilization time takes too long. Accordingly, the optimal EC beam width range is revealed to exist in the feedback stabilization of NTM.

  7. Frequency Properties Research of Elevator Drive System with Direct Torque Control-Pulse with Modulation

    Directory of Open Access Journals (Sweden)

    A. S. Koval

    2008-01-01

    Full Text Available In the article problems of frequency properties research for electric drive system with direct torque control and pulse width modulator are described. The mathematical description of elevator is present. Simplified mathematical description of direct torque control - pulse width modulator electric drive system is shown. Transfer functions for torque and speed loops are determined. Logarithmic frequency characteristics are computed. Damping properties of elevator drive system are estimated.

  8. Research on ripple rejection of DC power supply based on dual pulse width modulation

    Science.gov (United States)

    Liu, Xin; Liu, Peiyi

    2017-08-01

    With the development of power electronics technology, how to improve the output quality of DC power supply has become an important subject of recent scholars’ research. This paper put forward a new PWM control mode, the DC power supply output ripple is effectively suppressed. The theoretical basis is given by the principle analysis. Finally, the accuracy of the theoretical analysis is verified by simulation.

  9. space vector pulse width modulation of a multi-level diode clamped ...

    African Journals Online (AJOL)

    ES Obe

    nique in most industrial drives and control applications. It also focuses on the step by step ... the zero vector and two adjacent active vectors in determining the switching pro- cess of the multilevel DCC, quite unlike the .... Table 1: Switching states of an n-level Diode clamped converter. Switching States. S1. S2 ... Sn−2. Sa−1.

  10. Isolated PWM DC-AC SICAM with an active capacitive voltage clamp[Pulse Density Modulated; Pulse Width Modulation

    Energy Technology Data Exchange (ETDEWEB)

    Ljusev, P.

    2004-03-15

    In this report an isolated PWM DC-AC SICAM with an active capacitive voltage clamp is presented. AC-DC power supply is implemented in its simplest form: diode rectifier followed by a medium-size charge-storage capacitors and possibly with an EMC filter on the mains entrance. Isolation from the AC mains is achieved using a high frequency (HF) transformer, whose voltages are not audio-modulated. The latter simplifies the design and is expected to have many advantages over the approach where the transformer voltages are modulated in regards to the audio signal reference. Input stage is built as a DC-AC inverter (push-pull, half-bridge or a full-bridge) and operated with 50% duty cycle, with all the challenges to avoid transformer saturation and obtain symmetrical operation. On the secondary side the output section is implemented as rectifier+inverter AC-AC stage, i.e. a true bidirectional bridge, which operation is aimed towards amplification of the audio signal. In order to solve the problem with the commutation of the load current, a dead time between the incoming and outgoing bidirectional switch is implemented, while a capacitive voltage clamp is used to keep the induced overvoltage to reasonable levels. The energy stored in the clamping capacitor is not wasted as in the dissipative clamps, but is rather transferred back to the primary side for further processing using an auxiliary isolated single-switch converter, i.e. an active clamping technique is used. (au)

  11. Methods, systems and apparatus for adjusting duty cycle of pulse width modulated (PWM) waveforms

    Energy Technology Data Exchange (ETDEWEB)

    Gallegos-Lopez, Gabriel; Kinoshita, Michael H; Ransom, Ray M; Perisic, Milun

    2013-05-21

    Embodiments of the present invention relate to methods, systems and apparatus for controlling operation of a multi-phase machine in a vector controlled motor drive system when the multi-phase machine operates in an overmodulation region. The disclosed embodiments provide a mechanism for adjusting a duty cycle of PWM waveforms so that the correct phase voltage command signals are applied at the angle transitions. This can reduce variations/errors in the phase voltage command signals applied to the multi-phase machine so that phase current may be properly regulated thus reducing current/torque oscillation, which can in turn improve machine efficiency and performance, as well as utilization of the DC voltage source.

  12. Pulse width modulated push-pull driven parallel resonant converter with active free-wheel

    Science.gov (United States)

    Reass, William A.; Schrank, Louis

    2004-06-22

    An apparatus and method for high frequency alternating power generation to control kilowatts of supplied power in microseconds. The present invention includes a means for energy storage, push-pull switching means, control electronics, transformer means, resonant circuitry and means for excess energy recovery, all in electrical communication. A push-pull circuit works synchronously with a force commutated free-wheel transistor to provide current pulses to a transformer. A change in the conduction angle of the push-pull circuit changes the amount of energy coupled into the transformer's secondary oscillating circuit, thereby altering the induced secondary resonating voltage. At the end of each pulse, the force commutated free-wheel transistor causes residual excess energy in the primary circuit to be transmitted back to the storage capacitor for later use.

  13. Automatic Frequency Identification under Sample Loss in Sinusoidal Pulse Width Modulation Signals Using an Iterative Autocorrelation Algorithm

    Directory of Open Access Journals (Sweden)

    Alejandro Said

    2016-08-01

    Full Text Available In this work, we present a simple algorithm to calculate automatically the Fourier spectrum of a Sinusoidal Pulse Width Modulation Signal (SPWM. Modulated voltage signals of this kind are used in industry by speed drives to vary the speed of alternating current motors while maintaining a smooth torque. Nevertheless, the SPWM technique produces undesired harmonics, which yield stator heating and power losses. By monitoring these signals without human interaction, it is possible to identify the harmonic content of SPWM signals in a fast and continuous manner. The algorithm is based in the autocorrelation function, commonly used in radar and voice signal processing. Taking advantage of the symmetry properties of the autocorrelation, the algorithm is capable of estimating half of the period of the fundamental frequency; thus, allowing one to estimate the necessary number of samples to produce an accurate Fourier spectrum. To deal with the loss of samples, i.e., the scan backlog, the algorithm iteratively acquires and trims the discrete sequence of samples until the required number of samples reaches a stable value. The simulation shows that the algorithm is not affected by either the magnitude of the switching pulses or the acquisition noise.

  14. Double-pattern triangular pulse width modulation technique for high-accuracy high-speed 3D shape measurement.

    Science.gov (United States)

    Wang, Yajun; Jiang, Chufan; Zhang, Song

    2017-11-27

    Using 1-bit binary patterns for three-dimensional (3D) shape measurement has been demonstrated as being advantageous over using 8-bit sinusoidal patterns in terms of achievable speeds. However, the phase quality generated by binary pattern(s) typically are not high if only a small number of phase-shifted patterns are used. This paper proposes a method to improve the phase quality by representing each pattern with the difference of two binary patterns: the first binary pattern is generated by triangular pulse width modulation (TPWM) technique, and the second being π shifted from the first pattern that is also generated by TPWM technique. The phase is retrieved by applying a three-step phase-shifting algorithm to the difference patterns. Through optimizing the modulation frequency of the triangular carrier signal, we demonstrate that a high-quality phase can be generated for a wide range of fringe periods (e.g., from 18 to 1140 pixels) with only six binary patterns. Since only 1-bit binary patterns are required for 3D shape measurement, this paper will present a real-time 3D shape measurement system that can achieve 30 Hz.

  15. Comparison of a synergetic battery pack drive system to a pulse width modulated AC induction motor drive for an electric vehicle

    Energy Technology Data Exchange (ETDEWEB)

    Davis, A.; Salameh, Z.M. [Univ. of Massachusetts, Lowell, MA (United States). Dept. of Electrical Engineering; Eaves, S.S. [Eaves Devices, Charlestown, RI (United States)

    1999-06-01

    A new battery configuration technique and accompanying control circuitry, termed a Synergetic Battery Pack (SBP), is designed to work with Lithium batteries, and can be used as both an inverter for an electric vehicle AC induction motor drive and as a battery charger. In this paper, the performance of a Synergetic Battery Pack during motor drive operation is compared via computer simulation with a conventional motor drive which uses sinusoidal pulse width modulation (SPWM) to determine its effectiveness as a motor drive. The study showed that the drive efficiency was compatible with the conventional system, and offered a significant advantage in the lower frequency operating ranges. The voltage total harmonic distortion (THD) of the SBP was significantly lower than the PWM drive output, but the current THD was slightly higher due to the shape of the harmonic spectrum. In conclusion, the SBP is an effective alternative to a conventional drive, but the real advantage lies in its battery management capabilities and charger operation.

  16. Pulse width shaping of passively mode-locked soliton fiber laser via polarization control in carbon nanotube saturable absorber.

    Science.gov (United States)

    Jeong, Hwanseong; Choi, Sun Young; Rotermund, Fabian; Yeom, Dong-Il

    2013-11-04

    We report the continuous control of the pulse width of a passively mode-locked fiber laser via polarization state adjustment in a single-walled carbon nanotube saturable absorber (SWCNT-SA). The SWCNT, coated on the side-polished fiber, was fabricated with optimized conditions and used for stable mode-locking of the fiber laser without Q-switching instabilities for any polarization state of the laser intra-cavity. The 3-dB spectral bandwidth of the mode-locked pulses can be continuously tuned from 1.8 nm to 8.5 nm with the polarization control for a given laser cavity length and applied pump power. A pulse duration varying from 470 fs to 1.6 ps was also observed with a change in the spectral bandwidth. The linear and the nonlinear transmission properties of the SA were analyzed, and found to exhibit different modulation depths depending on the input polarization state in the SA. The largest modulation depth of the SA was observed at the polarization state of the transverse electric mode that delivers shortest pulses at the laser output.

  17. Valley Width Variation Controls on Riffle Location and Persistence on a Gravel Bed River

    Science.gov (United States)

    White, J. Q.; Pasternack, G. B.

    2007-12-01

    Numerous studies have examined the effect of constrictions on the formation of riffles and pools in rivers. Low velocity backwater effects are created above the constriction, with steep water surface slopes and flow acceleration after it. Such flow conditions cause varying sediment transport capacity, influencing the formation of riffles and pools near constrictions. Studies have shown that local bedrock outcrops, alluvial fans, sediment bars, and wood are capable of functioning as constrictions, but few address channel-confining valley walls as potential constrictions. Can variations in valley width influence riffle location and persistence? To address this question, research was performed on a valley-confined wandering gravel-bed reach of the regulated lower Yuba River from the Narrows Pool to the Highway 20 bridge. This reach has an average valley width of 164 m (range of 102-314 m). During 1853-1884, hydraulic gold mining filled this 7-km reach with ~26 m of mixed coarse sediment (totaling ~9-18 million cubic meters), creating a dynamic fluvial landscape comparable to recently deglaciated wandering gravel-bed streams. The hypothesis of this study was that riffles that persist over decades on wandering gravel-bed rivers are controlled by valley width variations. The study objectives were to (1) assess planform and elevation changes over 22 years and (2) correlate locations of persistent riffles with valley- wall constrictions. ArcGIS was used to measure valley width and changes in planform wetted area in georectified photo sets of this reach for 1984, 1986, 1991, 1996, 2002, 2004, 2005, and 2006. Detailed river valley DEMs were also available for 1999 and 2006 for measuring the recent incision rate, and pattern of the valley fill. Riffle crest locations for each year were plotted along with the valley width versus distance upstream, and all riffles crests that persisted for the entire duration were identified. The persistent riffle crests were statistically

  18. Pengaruh Penambahan PWM (Pulse Width Modulation Pada Generator HHO Tipe Dry Cell

    Directory of Open Access Journals (Sweden)

    Fungky Dyan Pertiwi

    2013-09-01

    Full Text Available Generator HHO memanfaatkan proses elektrolisis air agar mendapatkan gas H2. Namun, pada praktiknya pemakaian arus dari aki yang besar dan temperatur tinggi membuat bejana generator menjadi cepat rusak, sehingga dibutuhkan tambahan rangkaian elektronika PWM pada pengujian generator HHO guna mengatasi permasalahan tersebut. Penelitian menggunakan elektroda plat berjumlah 9 berdimensi 120mm 120mm, tebal 1mm dan dibatasi oleh o-ring dengan diameter 126mm, tebal 3mm. Pengujian dilakukan secara eksperimen dengan 2 kelompok yaitu kelompok control yang mana pengujian tanpa menggunakan PWM serta kelompok uji dimana pengujian menggunakan PWM dengan variasi duty cycle 30%, 50% dan 70%. Pengujian dilakukan hingga temperatur elektrolit 93oC. Hasil uji didapatkan bahwa arus, laju produksi dan efisiensi terbesar didapatkan pada pengujian tanpa PWM yang mencapai 60,6A, 6,033 10-6kg/s dan 25,69%. Namun, pada pengambilan data kedua efisiensi turun menjadi 19,74%. Penambahan PWM pada pengujian berpengaruh pada arus dan temperatur yang stabil meskipun laju produksi dan efisiensi lebih kecil daripada pengujian tanpa PWM. Pengujian dengan PWM pada duty cycle 70% menghasilkan laju produksi dan efisiensi terbesar yang mencapai 1,843 10-6 kg/s dan 15,19%.

  19. Controllable pulse width of bright similaritons in a tapered graded index diffraction decreasing waveguide

    Energy Technology Data Exchange (ETDEWEB)

    Prakash, S. Arun [Department of EEE, Anna University, Ramanathapuram 623513 (India); Malathi, V. [Department of EEE, Anna University, Regional office, Madurai (India); Mani Rajan, M. S., E-mail: senthilmanirajanofc@gmail.com [Department of Physics, Anna University, Ramanathapuram 623513 (India); Loomba, Shally [Department of Physics, Panjab University, Chandigarh 160014 (India)

    2016-03-15

    We obtain the bright similariton solutions for generalized inhomogeneous nonlinear Schrödinger equation (GINLSE) which governs the pulse propagation in a tapered graded index diffraction decreasing waveguide (DDW). The exact solutions have been worked out by employing similarity transformations which involve the mapping of the GINLSE to standard NLSE for the certain conditions of the parameters. By making use of the exact analytical solutions, we have investigated the dynamical behavior of optical similariton pairs and have suggested the methods to control them as they propagate through DDW. Moreover, pulse width of similariton is controlled through various profiles. These results are helpful to understand the similaritons in DDW and can be potentially useful for future experiments in optical communications which involve optical amplifiers and long-haul telecommunication networks.

  20. A Novel Transcranial Magnetic Stimulator Inducing Near Rectangular Pulses with Controllable Pulse Width (cTMS)

    Science.gov (United States)

    Jalinous, Reza; Lisanby, Sarah H.

    2013-01-01

    A novel transcranial magnetic stimulation (TMS) device with controllable pulse width (PW) and near rectangular pulse shape (cTMS) is described. The cTMS device uses an insulated gate bipolar transistor (IGBT) with appropriate snubbers to switch coil currents up to 7 kA, enabling PW control from 5 μs to over 100 μs. The near-rectangular induced electric field pulses use 22–34% less energy and generate 67–72% less coil heating compared to matched conventional cosine pulses. CTMS is used to stimulate rhesus monkey motor cortex in vivo with PWs of 20 to 100 μs, demonstrating the expected decrease of threshold pulse amplitude with increasing PW. The technological solutions used in the cTMS prototype can expand functionality, and reduce power consumption and coil heating in TMS, enhancing its research and therapeutic applications. PMID:18232369

  1. Reducing, by pulse width modulation, the curing temperature of a prototype high-power LED light curing unit.

    Science.gov (United States)

    Huang, Ta-Ko; Hung, Chun-Cheng; Tsai, Chi-Cheng

    2006-06-01

    Third-generation LEDs have high irradiance and efficiency, but the associated temperature rise is potentially hazardous to the pulp of teeth. We evaluated, during composite polymerization, the irradiance and temperature rise of a prototype high-power LED light curing unit (LCU) with optimal pulse width modulation (PWM), and then compared the results with four off-the-shelf high-power LCUs. A cavity was prepared in a tooth, and a composite resin layer was applied and cured. For each LCU, the irradiance and temperature changes at the pulp-dentin junction were measured. Microhardness (Vickers hardness) of cured composite samples was measured for each LCU. Our prototype had a final temperature of 36.4 +/- 1.3 degrees C and irradiance of 1,182 +/- 1 mW/cm2. The unit with the highest temperature had a temperature of 48.7 +/- 1.2 degrees C and an irradiance of 1,194 +/- 1 mW/cm2. Based on the results of the present study, it was shown that PWM technology reduced the curing temperature while retaining the polymerization effectiveness of a high-power LED LCU.

  2. Modelling and analysis of a high-performance Class D audio amplifier using unipolar pulse-width-modulation

    Science.gov (United States)

    Zhou, Zekun; Shi, Yue; Ming, Xin; Zhang, Bo; Li, Zhaoji; Chen, Zao

    2012-02-01

    A high-performance class D audio amplifier using unipolar pulse-width-modulation (PWM) with double-sided natural sampling is presented in this article. In order to comprehend and design the system properly, the class D audio amplifier is modelled and analysed. A wide range triangle-wave signal with good linearity and magnitude proportional to supply voltage is embedded in the proposed class D audio amplifier for maximum output power, high power supply rejection ratio (PSRR) and low total harmonic distortion (THD). Design results based on CSMC 0.5-µm 5-V complementary metal-oxide-semiconductor process demonstrate that the proposed class D audio amplifier can operate with supply voltage in the range 2.4-5.5 V and supports 2.8 W output power from a 5.5 V supply; the maximum efficiency is above 95%, the PSRR is -82 dB, the signal-to-noise ratio (SNR) is 97 dB and the total harmonic distortion plus noise (THD+N) is less than 0.1% between 20 and 20 kHz with output power 0.4 W; the quiescent current without load is 1.8 mA, and the shutdown current is 0.01 µA. The active area of the class-D audio power amplifier is 1.5 mm × 1.5 mm.

  3. FG Width Scalability of the 3-D Vertical FG NAND Using the Sidewall Control Gate (SCG)

    Science.gov (United States)

    Seo, Moon-Sik; Endoh, Tetsuo

    Recently, the 3-D vertical Floating Gate (FG) type NAND cell arrays with the Sidewall Control Gate (SCG), such as ESCG, DC-SF and S-SCG, are receiving attention to overcome the reliability issues of Charge Trap (CT) type device. Using this novel cell structure, highly reliable flash cell operations were successfully implemented without interference effect on the FG type cell. However, the 3-D vertical FG type cell has large cell size by about 60% for the cylindrical FG structure. In this point of view, we intensively investigate the scalability of the FG width of the 3-D vertical FG NAND cells. In case of the planar FG type NAND cell, the FG height cannot be scaled down due to the necessity of obtaining sufficient coupling ratio and high program speed. In contrast, for the 3-D vertical FG NAND with SCG, the FG is formed cylindrically, which is fully covered with surrounded CG, and very high CG coupling ratio can be achieved. As results, the scaling of FG width of the 3-D vertical FG NAND cell with S-SCG can be successfully demonstrated at 10nm regime, which is almost the same as the CT layer of recent BE-SONOS NAND.

  4. Virtual-vector-based space vector pulse width modulation of the DC-AC multilevel-clamped multilevel converter (MLC2)

    DEFF Research Database (Denmark)

    Rodriguez, Pedro; Busquets-Monge, Sergio; Blaabjerg, Frede

    2011-01-01

    This work presents the development of the space vector pulse width modulation (SVPWM) of a new multi-level converter topology. First, the proposed converter and its natural space vector diagram are presented. Secondly, a modified space vector diagram based on the virtual-vectors technique is shown...

  5. CMOS Transmitter using Pulse-Width Modulation Pre-Emphasis achieving 33dB Loss Compensation at 5-Gb/s

    NARCIS (Netherlands)

    Schrader, J.H.R.; Klumperink, Eric A.M.; Visschers, J.L.; Nauta, Bram

    2005-01-01

    A digital transmitter pre-emphasis technique is presented that is based on pulse-width modulation, instead of finite impulse response (FIR) filtering. The technique fits well to future high-speed low-voltage CMOS processes. A 0.13 /spl mu/m CMOS transmitter achieves more than 5 Gb/s (2-PAM) over 25

  6. CMOS Transmitter using Pulse-Width Modulation Pre-Emphasis achieving 33dB Loss Compensation at 5-Gb/s

    NARCIS (Netherlands)

    Schrader, J.H.R.; Klumperink, Eric A.M.; Visschers, J.L.; Nauta, Bram

    A digital transmitter pre-emphasis technique is presented that is based on pulse-width modulation, instead of finite impulse response (FIR) filtering. The technique fits well to future high-speed low-voltage CMOS processes. A 0.13 μm CMOS transmitter achieves more than 5 Gb/s (2-PAM) over 25 m of

  7. Controlling vibrational cooling with zero-width resonances: An adiabatic Floquet approach

    Science.gov (United States)

    Leclerc, Arnaud; Viennot, David; Jolicard, Georges; Lefebvre, Roland; Atabek, Osman

    2016-10-01

    In molecular photodissociation, some specific combinations of laser parameters (wavelength and intensity) lead to unexpected zero-width resonances (ZWRs) with, in principle, infinite lifetimes. Their potential to induce basic quenching mechanisms has recently been devised in the laser control of vibrational cooling through filtration strategies [O. Atabek et al., Phys. Rev. A 87, 031403(R) (2013), 10.1103/PhysRevA.87.031403]. A full quantum adiabatic control theory based on the adiabatic Floquet Hamiltonian is developed to show how a laser pulse could be envelope-shaped and frequency-chirped so as to protect a given initial vibrational state against dissociation, taking advantage of its continuous transport on the corresponding ZWR all along the pulse duration. As compared with previous control scenarios that actually suffered from nonadiabatic contamination, drastically different and much more efficient filtration goals are achieved. A semiclassical analysis helps us to find and interpret a complete map of ZWRs in the laser parameter plane. In addition, the choice of a given ZWR path, among the complete series identified by the semiclassical approach, turns out to be crucial for the cooling scheme, targeting a single vibrational state population left at the end of the pulse, while all others have almost completely decayed. The illustrative example, which has the potential to be transposed to other diatomics, is Na2 prepared by photoassociation in vibrationally hot but translationally and rotationally cold states.

  8. Glans penis width in patients with hypospadias compared to healthy controls.

    Science.gov (United States)

    Bush, Nicol Corbin; DaJusta, Daniel; Snodgrass, Warren T

    2013-12-01

    There are no reports of systematically-measured penile dimensions in boys with varying extents of hypospadias. To determine reference values, we prospectively measured maximum glans width in patients undergoing distal and proximal hypospadias repair as well as newborns undergoing elective circumcision. The maximum glans diameter was measured in consecutive boys aged 0-24 months presenting for newborn circumcision (controls), or repair of distal (distal shaft or glanular) and proximal (proximal shaft to perineal) hypospadias. Patients with proximal hypospadias and glans diameter injection once monthly for 2-3 treatments, with measurements recorded prior to the first injection, and again intra-operatively 3-4 weeks after the final injection. Data were obtained in 240 controls, 188 boys with distal hypospadias, and 39 boys with proximal hypospadias. Median ages were 1, 9 and 9 months, respectively. Males undergoing newborn circumcision were younger than both cohorts of hypospadias patients (p < 0.0001), but no difference in age was noted in those with distal and proximal hypospadias (p = 0.194). Average maximum glans diameters were significantly different: 14.3, 14.8, and 12.9 mm, respectively, for controls, distal and proximal hypospadias (p < 0.0001). Despite mean older age, 46 (24.5%) boys with distal hypospadias and 24 (61.5%) with proximal hypospadias had small glans diameter <14 mm. Increasing age was not correlated with increasing glans size in patients with distal or proximal hypospadias (r = -0.136, p = 0.062 and r = -0.089, p = 0.580) at 3-24 months of age. Some boys with distal and the majority of those with proximal hypospadias have a glans width less than that of the average normal newborn. Glans size does not correlate with age in patients with hypospadias between 3 and 24 months old, supporting the decision to operate as early as 3 months in some centers. Copyright © 2013. Published by Elsevier Ltd.

  9. Red cell distribution width and the risk of cerebral vein thrombosis: A case-control study.

    Science.gov (United States)

    Maino, Alberto; Abbattista, Maria; Bucciarelli, Paolo; Artoni, Andrea; Passamonti, Serena M; Lanfranconi, Silvia; Martinelli, Ida

    2017-03-01

    Red cell distribution width (RDW) is a marker of cardiovascular diseases and venous thromboembolism, but its role in cerebral vein thrombosis (CVT) is unknown. To investigate whether high values of RDW are associated with an increased risk of CVT. A case-control study of CVT patients (≥18years-old) referred to our center contrasted with healthy individuals. Odds ratios (ORs) were calculated for RDW values >90th percentile by multivariable logistic regression and adjusted for demographic characteristics, hemorheological parameters, renal function, fibrinogen and CRP. Quartiles based on the distribution of RDW values were used in an additional model to assess a dose-response relationship. The risk of CVT associated with the combined presence of high RDW and either thrombophilia abnormalities or oral contraceptive use was also estimated. 143 cases (median age 36years, 18-79) and 352 controls (42years, 18-80) were investigated. RDW values >90th percentile (>14.6%) were associated with an increased risk of CVT (OR 2.44, 95% CI 1.39-4.28). The association remained after further adjustment for hemorheological parameters (OR 3.73, 95% CI 1.72-8.09), inflammatory markers (OR 3.77, 95% CI 1.72-8.25) and renal function (OR 3.62, 95% CI 1.53-8.55). The risk appeared restricted to these extreme levels (>14.6%), as there was no graded association between values of RDW and CVT risk over quartiles. There was a synergistic effect on the risk of CVT for the combination of high RDW and thrombophilia abnormalities (OR 33.20, 95% CI 6.95-158.55) or oral contraceptive use (OR 37.99, 95% CI 8.78-164.45). Values of RDW >90th percentile are associated with CVT. Copyright © 2016 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.

  10. Controlling ρ width effects for a precise value of α in B → ρρ

    Science.gov (United States)

    Gronau, Michael; Rosner, Jonathan L.

    2017-03-01

    It has been pointed out that the currently most precise determination of the weak phase ϕ2 = α of the Cabibbo-Kobayashi-Maskawa (CKM) matrix achieved in B → ρρ decays is susceptible to a small correction at a level of (Γρ /mρ)2 due to an I = 1 amplitude caused by the ρ width. Using Breit-Wigner distributions for the two pairs of pions forming ρ mesons, we study the I = 1 contribution to B → ρρ decay rates as function of the width and location of the ρ band. We find that in the absence of a particular enhancement of the I = 1 amplitude reducing a single band to a width Γρ at SuperKEKB leads to results which are completely insensitive to the ρ width. If the I = 1 amplitude is dynamically enhanced relative to the I = 0 , 2 amplitude one could subject its contribution to a ;magnifying glass; measurement using two separated ρ bands of width Γρ. Subtraction of the I = 1 contribution from the measured decay rate would lead to a very precise determination of the I = 0 , 2 amplitude needed for performing the isospin analysis.

  11. Controlling ρ width effects for a precise value of α in B→ρρ

    Directory of Open Access Journals (Sweden)

    Michael Gronau

    2017-03-01

    Full Text Available It has been pointed out that the currently most precise determination of the weak phase ϕ2=α of the Cabibbo–Kobayashi–Maskawa (CKM matrix achieved in B→ρρ decays is susceptible to a small correction at a level of (Γρ/mρ2 due to an I=1 amplitude caused by the ρ width. Using Breit–Wigner distributions for the two pairs of pions forming ρ mesons, we study the I=1 contribution to B→ρρ decay rates as function of the width and location of the ρ band. We find that in the absence of a particular enhancement of the I=1 amplitude reducing a single band to a width Γρ at SuperKEKB leads to results which are completely insensitive to the ρ width. If the I=1 amplitude is dynamically enhanced relative to the I=0,2 amplitude one could subject its contribution to a “magnifying glass” measurement using two separated ρ bands of width Γρ. Subtraction of the I=1 contribution from the measured decay rate would lead to a very precise determination of the I=0,2 amplitude needed for performing the isospin analysis.

  12. ATLAS ITk Short-Strip Stave Prototype Module with Integrated DCDC Powering and Control

    CERN Document Server

    Greenall, Ashley; The ATLAS collaboration

    2017-01-01

    During the Phase II upgrade, the ATLAS detector at the LHC will be upgraded with a new Inner Tracker (ITk) detector. The ITk prototype barrel module design has adopted an integrated low mass assembly featuring single-sided flexible circuits, with readout ASICs, glued to the silicon strip sensor. Further integration has been achieved by the attachment of module DCDC powering, a HV sensor biasing switch and autonomous monitoring and control to the sensor. This low mass integrated module approach benefits further in a reduced width stave structure to which the modules are attached. The results of preliminary electrical tests of such an integrated module are presented.

  13. Monetary rewards modulate inhibitory control

    Directory of Open Access Journals (Sweden)

    Paula Marcela Herrera

    2014-05-01

    Full Text Available The ability to override a dominant response, often referred to as behavioural inhibiton, is considered a key element of executive cognition. Poor behavioural inhibition is a defining characteristic of several neurological and psychiatric populations. Recently, there has been increasing interest in the motivational dimension of behavioural inhibition, with some experiments incorporating emotional contingencies in classical inhibitory paradigms such as the Go/Nogo and Stop Signal Tasks. Several studies have reported a positive modulatory effect of reward on the performance of such tasks in pathological conditions such as substance abuse, pathological gambling, and ADHD. However, experiments that directly investigate the modulatory effects of reward magnitudes on the performance of inhibitory paradigms are rare and consequently, little is known about the finer grained relationship between motivation and self-control. Here, we probed the effect of reward and reward magnitude on behavioural inhibition using two modified version of the widely used Stop Signal Task. The first task compared no reward with reward, whilst the other compared two different reward magnitudes. The reward magnitude effect was confirmed by the second study, whereas it was less compelling in the first study, possibly due to the effect of having no reward in some conditions. In addition, our results showed a kick start effect over global performance measures. More specifically, there was a long lasting improvement in performance throughout the task, when participants received the highest reward magnitudes at the beginning of the protocol. These results demonstrate that individuals’ behavioural inhibition capacities are dynamic not static because they are modulated by the reward magnitude and initial reward history of the task at hand.

  14. Fin width dependence on gate controllability of InGaAs channel FinFETs with regrown source/drain

    Science.gov (United States)

    Kise, Nobukazu; Kinoshita, Haruki; Yukimachi, Atsushi; Kanazawa, Toru; Miyamoto, Yasuyuki

    2016-12-01

    In this paper, we report on the structure and characteristics of an indium gallium arsenide (InGaAs) channel fin field effect transistor (FinFET) with a regrown source/drain. The fabrication process we propose is suitable for forming a channel with a high aspect ratio. In simulations, the subthreshold characteristics and drain current (Id) were improved by reducing the fin width. Following the simulations, fabricated devices showed improved gate controllability after the fin width was reduced. A short-channel device (Lch = 50 nm, Hfin = 50 nm, and Wfin = 20 nm) showed an Id of 367 μA/μm and a minimum subthreshold swing (SSmin) of 211 mV/dec at Vd = 0.5 V. The maximum-to-minimum Id ratio was 105.

  15. Microprocessor-controlled CAMAC data link module

    Energy Technology Data Exchange (ETDEWEB)

    Potter, J.M.

    1978-05-01

    Communication between the central control computer and remote, satellite data-acquisition/control stations at the Clinton P. Anderson Meson Physics Facility (LAMPF) is presently accomplished through the use of CAMAC-based Data Link modules. With the advent of the microprocessor, a new philosophy for digital data communications has evolved. Data Link modules containing microprocessor controllers provide link management and communication network protocol through algorithms executed in the Data Link microprocessor. 13 figures.

  16. The Robust Control Mixer Module Method for Control Reconfiguration

    DEFF Research Database (Denmark)

    Yang, Z.; Blanke, M.

    1999-01-01

    into a LTI dynamical system, and furthermore multiple dynamical control mixer modules can be employed in our consideration. The H_{\\infty} control theory is used for the analysis and design of the robust control mixer modules. Finally, one practical robot arm system as benchmark is used to test the proposed...

  17. Free Electron Laser Pulse Control by Acousto Optic Modulators

    CERN Document Server

    Kanai, T; Yoshihashi-Suzuki, S

    2005-01-01

    Free Electron Laser (FEL) at Osaka University can be continuously varied in the range of 5.0-20.0 μm. A FEL has a double pulse structure. The structure consists of a train of macropulses of the pulse width 15 μs, and each macropulse contains a train of 330 micropulses of the pulse width 5 ps. The tunability and short pulse afford new medical applications such as investigation of protein dynamics and ablation of soft tissues. Precise control of micropulse train is very important for medical applications using FEL because macropulse with long pulse duration sometimes leads to undesirable thermal effects. FEL pulse control system using an acousto optic modulators (AOM) was developed in order to investigate of non-thermal effect between the FEL and tissue. This system provide a very good efficiency (~60 %) and a fast switching speed (>200 ns). A phosphorylated protein was irradiated with FEL that controlled the pulse. These result confirmed that the thermal effect is controlled by pulse durat...

  18. Trainer module for security control center operations

    Energy Technology Data Exchange (ETDEWEB)

    Bernard, E.A.

    1982-01-01

    An operator trainer module has been developed to be used with the security control center equipment to be installed as part of a safeguards physical protection system. The module is designed to provide improved training and testing capabilities for control center operators through the use of simulations for perimeter equipment operations. Operators, through the trainer module, can be challenged with a variety of realistic situations which require responsive action identical to that needed in an actual system. This permits a consistent evaluation and confirmation of operator capabilities prior to assignment as an operator and allows for periodic retesting to verify that adequate performance levels are maintained.

  19. Effects of interventions on normalizing step width during self-paced dual-belt treadmill walking with virtual reality, a randomised controlled trial.

    Science.gov (United States)

    Oude Lansink, I L B; van Kouwenhove, L; Dijkstra, P U; Postema, K; Hijmans, J M

    2017-10-01

    Step width is increased during dual-belt treadmill walking, in self-paced mode with virtual reality. Generally a familiarization period is thought to be necessary to normalize step width. The aim of this randomised study was to analyze the effects of two interventions on step width, to reduce the familiarization period. We used the GRAIL (Gait Real-time Analysis Interactive Lab), a dual-belt treadmill with virtual reality in the self-paced mode. Thirty healthy young adults were randomly allocated to three groups and asked to walk at their preferred speed for 5min. In the first session, the control-group received no intervention, the 'walk-on-the-line'-group was instructed to walk on a line, projected on the between-belt gap of the treadmill and the feedback-group received feedback about their current step width and were asked to reduce it. Interventions started after 1min and lasted 1min. During the second session, 7-10days later, no interventions were given. Linear mixed modeling showed that interventions did not have an effect on step width after the intervention period in session 1. Initial step width (second 30s) of session 1 was larger than initial step width of session 2. Step width normalized after 2min and variation in step width stabilized after 1min. Interventions do not reduce step width after intervention period. A 2-min familiarization period is sufficient to normalize and stabilize step width, in healthy young adults, regardless of interventions. A standardized intervention to normalize step width is not necessary. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Energy Efficiency of Induction Motors Running Off Frequency Converters with Pulse-Width Voltage Modulation{sup 1}

    Energy Technology Data Exchange (ETDEWEB)

    Shvetsov, N. K., E-mail: elmash@em.ispu.ru [V. I. Lenin Ivanovo State Power University (Russian Federation)

    2016-11-15

    The results of calculations of the increase in losses in an induction motor with frequency control and different forms of the supply voltage are presented. The calculations were performed by an analytic method based on harmonic analysis of the supply voltage as well as numerical calculation of the electromagnetic processes by the finite-element method.

  1. Pulse-Width Predictive Control for LTV Systems with Application to Spacecraft Rendezvous

    OpenAIRE

    Vazquez, Rafael; Gavilan, Francisco; Camacho, Eduardo F.

    2015-01-01

    This work presents a model predictive controller (MPC) that is able to handle linear time-varying (LTV) plants with PWM control. The MPC is based on a planner that employs a PAM or impulsive approximation as a hot-start and then uses explicit linearization around successive PWM solutions for rapidly improving the solution by means of linear programming. As an example, the problem of rendezvous of spacecraft for eccentric target orbits is considered. The problem is modeled by the LTV Tschauner...

  2. Investigation on a Novel Discontinuous Pulse-Width Modulation Algorithm for Single-phase Voltage Source Rectifier

    DEFF Research Database (Denmark)

    Qu, Hao; Yang, Xijun; Guo, Yougui

    2014-01-01

    Single-phase voltage source converter (VSC) is an important power electronic converter (PEC), including single-phase voltage source inverter (VSI), single-phase voltage source rectifier (VSR), single-phase active power filter (APF) and single-phase grid-connection inverter (GCI). Single-phase VSC......-sequence component injection, in order to reduce power loss and increased overall efficiency. And then by reconstructing the other two phase input voltages and currents, the transformation from stationary frame (abc) to rotating frame (dq frame) is designed. Finally, a PI regulator based controller for single......-phase VSR is analyzed and simulated by means of MATLAB/SIMULINK by using the presented DPWM and dq transformation. The simulation results show the validation of the above DPWM algorithm and control theory....

  3. Bifurcation and Chaos in a Pulse Width modulation controlled Buck Converter

    DEFF Research Database (Denmark)

    Kocewiak, Lukasz; Bak, Claus Leth; Munk-Nielsen, Stig

    2007-01-01

    by a system of piecewise-smooth nonautonomous differential equations. The research are focused on chaotic oscillations analysis and analytical search for bifurcations dependent on parameter. The most frequent route to chaos by the period doubling is observed in the second order DC-DC buck converter. Other...... bifurcations as a complex behaviour in power electronic system evidence are also described. In order to verify theoretical study the experimental DC-DC buck converter was build. The results obtained from three sources were presented and compared. A very good agreement between theory and experiment was observed....

  4. Software based controls module development

    Energy Technology Data Exchange (ETDEWEB)

    Graves, v.b.; kelley, g; welch, j.c.

    1999-12-10

    A project was initiated at the Oak Ridge Y-12 Plant to implement software geometric error compensation within a PC-based machine tool controller from Manufacturing Data Systems, Inc. This project may be the first in which this type of compensation system was implemented in a commercially available machine tool controller totally in software. Previous implementations typically required using an external computer and hardware to interface through the position feedback loop of the controller because direct access to the controller software was not available. The test-bed machine for this project was a 2-axis Excello 921 T-base lathe. A mathematical error model of the lathe was created using homogeneous transformation matrices to relate the positions of the machine's slides to each other and to a world reference system. Equations describing the effects of the geometric errors were derived from the model. A software architecture was developed to support geometric error compensation for machine tools with up to 3 linear axes. Rotary axes were not supported in this implementation, but the developed architecture would not preclude their support in the future. Specific implementations will be dependent upon the configuration of the machine tool. A laser measuring system from Automated Precision, Inc. was used to characterize the lathe's geometric errors as functions of axis position and direction of motion. Multiple data files generated by the laser system were combined into a single Error File that was read at system startup and used by the compensation system to provide real-time position adjustments to the axis servos. A Renishaw Ballbar was used to evaluate the compensation system. Static positioning tests were conducted in an attempt to observe improved positioning accuracy with the compensation system enabled. These tests gave inconsistent results due to the lathe's inability to position the tool repeatably. The development of the architecture and

  5. Real-time microscopic 3D shape measurement based on optimized pulse-width-modulation binary fringe projection

    Science.gov (United States)

    Hu, Yan; Chen, Qian; Feng, Shijie; Tao, Tianyang; Li, Hui; Zuo, Chao

    2017-07-01

    In recent years, tremendous progress has been made in 3D measurement techniques, contributing to the realization of faster and more accurate 3D measurement. As a representative of these techniques, fringe projection profilometry (FPP) has become a commonly used method for real-time 3D measurement, such as real-time quality control and online inspection. To date, most related research has been concerned with macroscopic 3D measurement, but microscopic 3D measurement, especially real-time microscopic 3D measurement, is rarely reported. However, microscopic 3D measurement plays an important role in 3D metrology and is indispensable in some applications in measuring micro scale objects like the accurate metrology of MEMS components of the final devices to ensure their proper performance. In this paper, we proposed a method which effectively combines optimized binary structured patterns with a number-theoretical phase unwrapping algorithm to realize real-time microscopic 3D measurement. A slight defocusing of our optimized binary patterns can considerably alleviate the measurement error based on four-step phase-shifting FPP, providing the binary patterns with a comparable performance to ideal sinusoidal patterns. The static measurement accuracy can reach 8 μm, and the experimental results of a vibrating earphone diaphragm reveal that our system can successfully realize real-time 3D measurement of 120 frames per second (FPS) with a measurement range of 8~\\text{mm}× 6~\\text{mm} in lateral and 8 mm in depth.

  6. Rapid fabrication method of a microneedle mold with controllable needle height and width.

    Science.gov (United States)

    Lin, Yen-Heng; Lee, I-Chi; Hsu, Wei-Chieh; Hsu, Ching-Hong; Chang, Kai-Ping; Gao, Shao-Syuan

    2016-10-01

    The main issue of transdermal drug delivery is that macromolecular drugs cannot diffuse through the stratum corneum of skin. Many studies have pursued micro-sized needles encapsulated with drugs to overcome this problem, as these needles can pierce the stratum corneum and allow drugs to enter the circulatory system of the human body. However, most microneedle fabrication processes are time-consuming and require expensive equipment. In this study, we demonstrate a rapid method for fabricating a microneedle mold using drawing lithography and a UV-cured resin. The mold was filled with a water-soluble material, polyvinylpyrrolidone (PVP), which was then demolded to produce a water-soluble microneedle array. The results of an in vitro skin insertion test using PVP microneedles and pig ear skin demonstrated the feasibility of the microneedle mold. In addition, by controlling the viscosity of the UV-cured resin through various heat treatments, microneedles with different heights and aspect ratios were produced. Compared with other methods, this technology significantly simplifies and accelerates the mold fabrication process. In addition, the required equipment is relatively simple and inexpensive. Through this technology, we can rapidly fabricate microneedle molds with controllable dimensions for various applications.

  7. Pulse-Width Modulation Pre Emphasis applied in a Wireline Transmitter, achieving 33dB Loss Compensation at 5-Gb/s in 0.13-μm CMOS

    NARCIS (Netherlands)

    Schrader, J.H.R.; Klumperink, Eric A.M.; Visschers, J.L.; Nauta, Bram

    2006-01-01

    Abstract—A transmitter pre-emphasis technique for copper cable equalization is presented that is based on pulse-width modulation (PWM). This technique is an alternative to the usual 2-tap symbol-spaced FIR (SSF) pre-emphasis. The technique uses timing resolution instead of amplitude resolution to

  8. Serotonergic modulation of spinal motor control

    DEFF Research Database (Denmark)

    Perrier, Jean-Francois Marie; Cotel, Florence

    2015-01-01

    Serotonin (5-HT) is a monoamine that powerfully modulates spinal motor control by acting on intrasynaptic and extrasynaptic receptors. Here we review the diversity of 5-HT actions on locomotor and motoneuronal activities. Two approaches have been used on in vitro spinal cord preparations: either...... and promotes the excitability of motoneurons, while stronger release inhibits rhythmic activity and motoneuron firing. This latter effect is responsible for central fatigue and secures rotation of motor units....

  9. Fuzzy Logic Controlled Solar Module for Driving Three- Phase Induction Motor

    Science.gov (United States)

    Afiqah Zainal, Nurul; Sooi Tat, Chan; Ajisman

    2016-02-01

    Renewable energy produced by solar module gives advantages for generated three- phase induction motor in remote area. But, solar module's ou tput is uncertain and complex. Fuzzy logic controller is one of controllers that can handle non-linear system and maximum power of solar module. Fuzzy logic controller used for Maximum Power Point Tracking (MPPT) technique to control Pulse-Width Modulation (PWM) for switching power electronics circuit. DC-DC boost converter used to boost up photovoltaic voltage to desired output and supply voltage source inverter which controlled by three-phase PWM generated by microcontroller. IGBT switched Voltage source inverter (VSI) produced alternating current (AC) voltage from direct current (DC) source to control speed of three-phase induction motor from boost converter output. Results showed that, the output power of solar module is optimized and controlled by using fuzzy logic controller. Besides that, the three-phase induction motor can be drive and control using VSI switching by the PWM signal generated by the fuzzy logic controller. This concluded that the non-linear system can be controlled and used in driving three-phase induction motor.

  10. Interference Control Modulations Over Conscious Perception

    Directory of Open Access Journals (Sweden)

    Itsaso Colás

    2017-05-01

    Full Text Available The relation between attention and consciousness has been a controversial topic over the last decade. Although there seems to be an agreement on their distinction at the functional level, no consensus has been reached about attentional processes being or not necessary for conscious perception. Previous studies have explored the relation of alerting and orienting systems of attention and conscious perception, but the impact of the anterior executive attention system on conscious access remains unexplored. In the present study, we investigated the behavioral interaction between executive attention and conscious perception, testing control mechanisms both at stimulus-level representation and after error commission. We presented a classical Stroop task, manipulating the proportion of congruent and incongruent trials, and analyzed the effect of reactive and proactive control on the conscious perception of near-threshold stimuli. Reactive control elicited under high proportion congruent conditions influenced participants’ decision criterion, whereas proactive control elicited under low proportion congruent conditions was ineffective in modulating conscious perception. In addition, error commission affected both perceptual sensitivity to detect near-threshold information and response criterion. These results suggest that reactivation of task goals through reactive control strategies in conflict situations impacts decision stages of conscious processing, whereas interference control elicited by error commission impacts both perceptual sensitivity and decision stages of conscious processing. We discuss the implications of our results for the gateway hypothesis about attention and consciousness, as they showed that interference control (both at stimulus-level representation and after error commission can modulate the conscious access of near-threshold stimuli.

  11. Living cellular construct for increasing the width of keratinized gingiva: results from a randomized, within-patient, controlled trial.

    Science.gov (United States)

    McGuire, Michael K; Scheyer, E Todd; Nevins, Marc L; Neiva, Rodrigo; Cochran, David L; Mellonig, James T; Giannobile, William V; Bates, Damien

    2011-10-01

    The standard of care for increasing keratinized gingiva adjacent to teeth that do not require root coverage is the free gingival graft (FGG). A pilot study indicated that the use of a living cellular construct (LCC) could be effective in this clinical scenario. A pivotal, multicenter, randomized, within-patient, controlled, open-label trial was conducted (N = 96 patients). After removing the mucosa and keratinized gingiva from the test site, either an LCC or FGG was applied. The primary efficacy endpoint was the ability of the LCC to regenerate ≥2 mm keratinized gingiva at 6 months. Secondary measures were the same color and texture as the adjacent tissue, a 1-mm width of keratinized gingiva at 6 months, patient treatment preference, surgical site sensitivity at 1 week, and patient-reported pain after 3 days. Safety was assessed by reports of adverse events. At 6 months, the LCC regenerated ≥2 mm of keratinized gingiva in 95.3% of patients (81 of 85 patients; P FGG generated more keratinized gingiva than the LCC (4.57 ± 1.0 mm versus 3.2 ± 1.1 mm, respectively). The gingiva regenerated with the LCC matched the color and texture of the adjacent gingiva. All patients achieved ≥1 mm keratinized gingiva with the LCC treatment by 6 months, and more patients preferred treatment with the LCC than with the FGG. No difference in sensitivity or pain was noted between the treatments. The treatments were well tolerated, and reported adverse events were typical for this type of periodontal surgery. The use of an LCC may provide a safe and effective therapy for augmenting the zone of keratinized gingiva.

  12. Microeconomics of 300-mm process module control

    Science.gov (United States)

    Monahan, Kevin M.; Chatterjee, Arun K.; Falessi, Georges; Levy, Ady; Stoller, Meryl D.

    2001-08-01

    Simple microeconomic models that directly link metrology, yield, and profitability are rare or non-existent. In this work, we validate and apply such a model. Using a small number of input parameters, we explain current yield management practices in 200 mm factories. The model is then used to extrapolate requirements for 300 mm factories, including the impact of simultaneous technology transitions to 130nm lithography and integrated metrology. To support our conclusions, we use examples relevant to factory-wide photo module control.

  13. High density, multi-range analog output Versa Module Europa board for control system applications

    Science.gov (United States)

    Singh, Kundan; Das, Ajit Lal

    2014-01-01

    A new VMEDAC64, 12-bit 64 channel digital-to-analog converter, a Versa Module Europa (VME) module, features 64 analog voltage outputs with user selectable multiple ranges, has been developed for control system applications at Inter University Accelerator Centre. The FPGA (Field Programmable Gate Array) is the module's core, i.e., it implements the DAC control logic and complexity of VMEbus slave interface logic. The VMEbus slave interface and DAC control logic are completely designed and implemented on a single FPGA chip to achieve high density of 64 channels in a single width VME module and will reduce the module count in the control system applications, and hence will reduce the power consumption and cost of overall system. One of our early design goals was to develop the VME interface such that it can be easily integrated with the peripheral devices and satisfy the timing specifications of VME standard. The modular design of this module reduces the amount of time required to develop other custom modules for control system. The VME slave interface is written as a single component inside FPGA which will be used as a basic building block for any VMEbus interface project. The module offers multiple output voltage ranges depending upon the requirement. The output voltage range can be reduced or expanded by writing range selection bits in the control register. The module has programmable refresh rate and by default hold capacitors in the sample and hold circuit for each channel are charged periodically every 7.040 ms (i.e., update frequency 284 Hz). Each channel has software controlled output switch which disconnects analog output from the field. The modularity in the firmware design on FPGA makes the debugging very easy. On-board DC/DC converters are incorporated for isolated power supply for the analog section of the board.

  14. Nonlinear Control of an Open-Loop Open-Winding Motor System with Modulated Converters

    Directory of Open Access Journals (Sweden)

    Oleschuk V.I.

    2017-04-01

    Full Text Available Purpose of this work - to provide wider control opportunities for multiphase open-end winding motor drive by modification of basic scheme of space-vector pulse-width modulation (PWM. It has been shown, that the proposed development of basic PWM scheme insures available solutions for realization of specific control dependences and modes of operation of adjustable speed ac drives with different types and kinds of loads. Suitable algorithms of PWM of converters of multiphase drive have been analyzed and compared. Extensive simulation studies have been executed for evaluation of performance and effectiveness of the proposed control strategy. Assessment of harmonic composition of the phase voltages of drive system with modified scheme of space-vector modulation has been done. Results of the executed simulations proved the fact, that the developed techniques of space-vector pulse-width modulation allow providing quarter-wave or half-wave symmetry of waveforms of the output voltage of six-phase adjustable speed drive systems during the analyzed non-standard modes and regimes of its operation.

  15. Implementation of Carrier-Based Simple Boost Pulse Width Modulation (PWM) for Z-Source Inverter (ZSI) using Field Programming Gate Array (FPGA)

    Science.gov (United States)

    Muhammad, M.; Rasin, Z.; Jidin, A.

    2017-08-01

    In recent years, the research on the Z-source inverter (ZSI) has received a wide acceptance due to its attractive solution for example in the renewable energy interface that requires voltage boost capability. The conventional inverter circuit based on the SPWM technique for example does not able to fully utilize its DC input voltage to produce a greater output voltage. The ZSI shoot-through implementation in high switching frequency requires a processor with fast sampling and high precision. In simulation, this can be easily carried out with the available advanced engineering software. In the hardware implementation however, the processor used is not only handle the switching, but also needs to read the data obtained by the sensor, voltage and current control, information display etc. This limits the capacity that can be used to implement the switching fast sampling with high precision. The aims of this work are to implement high precision of carrier-based simple boost PWM for ZSI using FPGA and to verify its real time hardware implementation. The high precision of PWM control algorithm based on the FPGA platform is verified by comparing the simulation results with the experimental results for different modulation index and boost factor, and a good agreement is concluded. It is observed that the application of FPGA reduces complexity, increases speed and the design of the switching technique can be altered without having to modify the hardware implementation.

  16. Sub-15 nm nano-pattern generation by spacer width control for high density precisely positioned self-assembled device nanomanufacturing

    KAUST Repository

    Rojas, Jhonathan Prieto

    2012-08-01

    We present a conventional micro-fabrication based thin film vertical sidewall (spacer) width controlled nano-gap fabrication process to create arrays of nanopatterns for high density precisely positioned self-assembled nanoelectronics device integration. We have used conventional optical lithography to create base structures and then silicon nitride (Si 3N4) based spacer formation via reactive ion etching. Control of Si3N4 thickness provides accurate control of vertical sidewall (spacer) besides the base structures. Nano-gaps are fabricated between two adjacent spacers whereas the width of the gap depends on the gap between two adjacent base structures minus width of adjacent spacers. We demonstrate the process using a 32 nm node complementary metal oxide semiconductor (CMOS) platform to show its compatibility for very large scale heterogeneous integration of top-down and bottom-up fabrication as well as conventional and selfassembled nanodevices. This process opens up clear opportunity to overcome the decade long challenge of high density integration of self-assembled devices with precise position control. © 2012 IEEE.

  17. Exotic states in the strong-field control of {{\\rm{H}}}_{2}^{+} dissociation dynamics: from exceptional points to zero-width resonances

    Science.gov (United States)

    Leclerc, Arnaud; Viennot, David; Jolicard, Georges; Lefebvre, Roland; Atabek, Osman

    2017-12-01

    {{{H}}}2+ is an ideal candidate for the detailed study of strong-field coherent control strategies inspired by basic mechanisms referring to some specific photodissociation resonances. Two of them are considered in this work, namely: zero-width resonances (ZWRs) and coalescing pairs of resonances at exceptional points (EPs). An adiabatic transport theory based on the Floquet Hamiltonian formalism is developed within the challenging context of multiphoton dynamics involving nuclear continua. It is shown that a rigorous treatment is only possible for ZWRs, whereas adiabatic transport mediated by EPs is subjected to restrictions. Numerical maps of resonance widths and non-adiabatic couplings in the laser parameter plane help in optimally shaping control pulses. Full time-dependent wavepacket dynamics shows the possibility of selective, robust filtration and vibrational population transfers, within experimentally feasible criteria.

  18. ATLAS ITk Short Strip Prototype Module with Integrated DCDC Powering and Control Phase II Upgrade of the ATLAS Inner Tracker detector at the HL - LHC

    CERN Document Server

    Greenall, Ashley; The ATLAS collaboration

    2017-01-01

    The prototype Barrel module design, for the Phase II upgrade of the of the new Inner Tracker (ITk) detector at the LHC, has adopted an integrated low mass assembly featuring single-sided flexible circuits, with readout ASICs, glued to the silicon strip sensor. Further integration has been achieved by the attachment of module DCDC powering, HV sensor biasing switch and autonomous monitoring and control to the sensor. This low mass, integrated module approach benefits further in a reduced width stave structure to which the modules are attached. The results of preliminary electrical tests of such an integrated module will be presented.

  19. Nanorack Compatible Standardized Data Processing, Communication, and Control Module Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This Phase I study will design and develop a NanoRacks Control Module (NCM) that provides communications, control functions and data processing in a NanoRacks...

  20. Controlling a Chaotic System through Control Parameter Self-Modulation

    Energy Technology Data Exchange (ETDEWEB)

    Pastor, I.

    1994-07-01

    A method for obtaining active control of a chaotic system based on the modulation of a control parameter by adding to it a small perturbation proportional to one output signal is proposed. From a theoretical point of view, chaos can be stabilized in the framework of this method because small modifications of the vector field controlling the dynamics are allowed, and thus some of the previously oxi sting unstable periodic trajectories can be made stable. The method is much inspired on recent treatments of some related problems, and i t is compared with them. One of its most attractive features is that is should be very easy to implement it on real experiments. The method is tested on a system of ordinary differential equations model ling the coupling of two se If - oscillating electronic circuits (van der Pol oscillators). Some brief comments are made on the no possibility that it could be applied to complex spatio-temporal systems where multiple chaotic structures can coexist for some values of the control parameters. (Author) 28 refs.

  1. Control of Moisture Ingress into Photovoltaic Modules

    Energy Technology Data Exchange (ETDEWEB)

    Kempe, M. D.

    2005-02-01

    During long-term exposure of photovoltaic modules to environmental stress, the ingress of water into the module is correlated with decreased performance. By using diffusivity measurements for water through encapsulants such as ethylene vinyl acetate (EVA), we have modeled moisture ingress using a finite-element analysis with atmospheric data from various locations such as Miami, Florida. This analysis shows that because of the high diffusivity of EVA, even an impermeable glass back-sheet alone is incapable of preventing significant moisture ingress from the edges for a 20-year lifecycle. This result has led us to investigate ways to protect modules from moisture through the use of different encapsulating chemistries and materials.

  2. Controlling the evolution of nondiffracting speckle by complex amplitude modulation on a phase-only spatial light modulator

    CSIR Research Space (South Africa)

    Dudley, Angela L

    2011-09-01

    Full Text Available amplitude modulation on a phase-only spatial light modulator to implement controlled ring-slit experiments for the generation of nondiffracting speckle fields. The structure of the nondiffracting speckle due to binary and continuous phase modulations...

  3. Wheel slip control of ABS using ER valve pressure modulator

    Science.gov (United States)

    Choi, Seung-Bok; Cho, Myung-Soo; Kim, Yong-Il; Choi, Young-Tai; Wereley, Norman M.

    2004-07-01

    This paper presents a wheel slip control via sliding mode controller for a new anti-lock brake system (ABS) of a passenger vehicle using electrorheological (ER) valve pressure modulator. The principal design parameters of the ER valves and hydraulic booster are appropriately determined by considering braking pressure variation during ABS operation. An electrically controllable pressure modulator using the ER valves is then constructed and its governing equations are derived. Subsequently, the pressure control performance of the new pressure modulator is experimentally evaluated. The governing equations of motion for a quarter car wheel model are derived and the sliding mode controller is formulated for wheel slip control. Hardware in the loop simulation (HILS) for braking performance evaluation is undertaken in order to demonstrate the effectiveness of the proposed ABS associated with the ER valve pressure modulator.

  4. Positive Affect Modulates Flexibility and Evaluative Control

    Science.gov (United States)

    van Wouwe, Nelleke C.; Band, Guido P. H.; Ridderinkhof, K. Richard

    2011-01-01

    The ability to interact with a constantly changing environment requires a balance between maintaining the currently relevant working memory content and being sensitive to potentially relevant new information that should be given priority access to working memory. Mesocortical dopamine projections to frontal brain areas modulate working memory…

  5. Sliding mode control the delta-sigma modulation approach

    CERN Document Server

    Sira-Ramírez, Hebertt

    2015-01-01

    This monograph presents a novel method of sliding mode control for switch-regulated nonlinear systems. The Delta Sigma modulation approach allows one to implement a continuous control scheme using one or multiple, independent switches, thus effectively merging the available linear and nonlinear controller design techniques with sliding mode control.   Sliding Mode Control: The Delta-Sigma Modulation Approach, combines rigorous mathematical derivation of the unique features of Sliding Mode Control and Delta-Sigma modulation with numerous illustrative examples from diverse areas of engineering. In addition, engineering case studies demonstrate the applicability of the technique and the ease with which one can implement the exposed results. This book will appeal to researchers in control engineering and can be used as graduate-level textbook for a first course on sliding mode control.

  6. Effects of interventions on normalizing step width during self-paced dual-belt treadmill walking with virtual reality, a randomised controlled trial

    NARCIS (Netherlands)

    Lansink, I. L. B. Oude; van Kouwenhove, L.; Dijkstra, P. U.; Postema, K.; Hijmans, J. M.

    2017-01-01

    Background: Step width is increased during dual-belt treadmill walking, in self-paced mode with virtual reality. Generally a familiarization period is thought to be necessary to normalize step width. Aim: The aim of this randomised study was to analyze the effects of two interventions on step width,

  7. Control Performance of Vehicle Abs Featuring ER Valve Pressure Modulator

    Science.gov (United States)

    Cho, M. S.; Choi, S. B.; Wereley, N. M.

    In this work, an electrically controllable anti-lock brake system (ABS) for passenger vehicle is developed by utilizing electrorheological (ER) fluid. A pressure modulator which consists of a cylindrical ER valve and the hydraulic booster is constructed in order to achieve sufficient brake pressure variation during ABS operation. The principal design parameters of the modulator are determined by considering ER properties as well as required braking pressure. After investigating pressure controllability of the modulator, a vehicle model which is integrated with the proposed pressure modulator is formulated to design yaw rate controller. A sliding mode controller is designed to obtain desired yaw rate, and the friction forces between roads and wheels are estimated via the estimator. Braking performances of the proposed ABS under various roads are evaluated through the hardware-in-the-loop-simulation (HILS) and the steering stability during braking operation is demonstrated by undertaking split-μ test.

  8. Multiphase clock generators with controlled clock impulse width for programmable high order rotator SC FIR filters realized in 0.35 μm CMOS technology

    Science.gov (United States)

    Dlugosz, Rafal; Pawlowski, Pawel; Dabrowski, Adam

    2005-06-01

    Complexity of clock generator is one of the most important parameters in the design and optimization of switched-capacitor (SC) finite impulse response (FIR) filters. There are different SC FIR filter architectures. Some of them need a simple clock generator but the others require a quite complicated multiphase clock system. In the latter case an external clock system (i.e., outside the integrated circuit) is unrealistic because of a great number of the required external pins. We have implemented various SC FIR filter architectures together with complex internal clock generators in the CMOS 0.8 μm and 0.35 μm technologies. One of the most important problems in the design process was the optimization of waveforms and widths of the clock impulses. SC FIR filters are very sensitive to parameters of clock systems. Thus the clock generators must be designed very precisely. We demonstrate results of the design of the 64-phase clock generator for a programmable rotator SC FIR filter. In our approach the width of the clock impulses is controlled by two external signals. This is a very convenient solution, because optimization of the clock impulses, which was difficult in other approaches, is currently much easier. The internal clock generator area is ca. 0.15 mm2 in the CMOS 0.35 μm technology, i.e., only 7 % of the entire SC FIR filter chip area.

  9. Electrooptic Modulators with Controlled Frequency Responses by Using Nonperiodically Polarization-Reversed Structure

    Directory of Open Access Journals (Sweden)

    Ha Viet Pham

    2008-01-01

    Full Text Available We discuss a new method to design traveling-wave electrooptic modulators with controlled frequency responses using nonperiodically polarization-reversed structure. Using our method, the frequency responses of both magnitude and phase of modulation index are controllable. Several electrooptic modulators for advanced modulation formats such as duobinary modulation and wideband single-sideband modulation are proposed.

  10. A general approach for temperature modulated thermogravimetry: Extension to non-periodical and event-controlled modulation

    Energy Technology Data Exchange (ETDEWEB)

    Schawe, J.E.K., E-mail: juergen.schawe@mt.com

    2014-10-10

    Highlights: • The temperature modulated TGA technique is expanded to non-periodic modulation functions. • The use of a stochastic modulation function is tested. • The concept of the new technique, the event controlled temperature modulated TGA is introduced. • The event control adapted the intensity of the modulation function and the characteristic modulation time. The result is an optimized modulation. - Abstract: Sinusoidal temperature modulated thermogravimetric analysis (TMTGA) has been proposed to get kinetic data on reactions that were investigated by TGA 45 years ago by Flynn and later by Blaine and Hahn. Because of general uncertainties of this technique, we developed a generalized approach for TMTGA using any modulation function, i.e., periodic as well as non-periodic. As a consequence of an error discussion of a TMDSC experiment, we present a new concept of the event controlled modulation function.

  11. Grid-connected of photovoltaic module using nonlinear control

    DEFF Research Database (Denmark)

    El Fadil, H.; Giri, F.; Guerrero, Josep M.

    2012-01-01

    The problem of controlling single-phase grid connected photovoltaic (PV) system is considered. The control objective is fourfold: (i) asymptotic stability of the closed loop system, (ii) maximum power point tracking (MPPT) of PV module (iii) tight regulation of the DC bus voltage, and (iv) unity...

  12. Pressure tracking control of vehicle ABS using piezo valve modulator

    Science.gov (United States)

    Jeon, Juncheol; Choi, Seung-Bok

    2011-03-01

    This paper presents a wheel slip control for the ABS(anti-lock brake system) of a passenger vehicle using a controllable piezo valve modulator. The ABS is designed to optimize for braking effectiveness and good steerability. As a first step, the principal design parameters of the piezo valve and pressure modulator are appropriately determined by considering the braking pressure variation during the ABS operation. The proposed piezo valve consists of a flapper, pneumatic circuit and a piezostack actuator. In order to get wide control range of the pressure, the pressure modulator is desired. The modulator consists of a dual-type cylinder filled with different substances (fluid and gas) and a piston rod moving vertical axis to transmit the force. Subsequently, a quarter car wheel slip model is formulated and integrated with the governing equation of the piezo valve modulator. A sliding mode controller to achieve the desired slip rate is then designed and implemented. Braking control performances such as brake pressure and slip rate are evaluated via computer simulations.

  13. Full quaternion based finite-time cascade attitude control approach via pulse modulation synthesis for a spacecraft.

    Science.gov (United States)

    Mazinan, A H; Pasand, M; Soltani, B

    2015-09-01

    In the aspect of further development of investigations in the area of spacecraft modeling and analysis of the control scheme, a new hybrid finite-time robust three-axis cascade attitude control approach is proposed via pulse modulation synthesis. The full quaternion based control approach proposed here is organized in association with both the inner and the outer closed loops. It is shown that the inner closed loop, which consists of the sliding mode finite-time control approach, the pulse width pulse frequency modulator, the control allocation and finally the dynamics of the spacecraft is realized to track the three-axis referenced commands of the angular velocities. The pulse width pulse frequency modulators are in fact employed in the inner closed loop to accommodate the control signals to a number of on-off thrusters, while the control allocation algorithm provides the commanded firing times for the reaction control thrusters in the overactuated spacecraft. Hereinafter, the outer closed loop, which consists of the proportional linear control approach and the kinematics of the spacecraft is correspondingly designed to deal with the attitude angles that are presented by quaternion vector. It should be noted that the main motivation of the present research is to realize a hybrid control method by using linear and nonlinear terms and to provide a reliable and robust control structure, which is able to track time varying three-axis referenced commands. Subsequently, a stability analysis is presented to verify the performance of the overall proposed cascade attitude control approach. To prove the effectiveness of the presented approach, a thorough investigation is presented compared to a number of recent corresponding benchmarks. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

  14. Comparison of radiographic joint space width and magnetic resonance imaging for prediction of knee replacement: A longitudinal case-control study from the Osteoarthritis Initiative

    Energy Technology Data Exchange (ETDEWEB)

    Eckstein, Felix; Wirth, Wolfgang; Cotofana, Sebastian [Paracelsus Medical University Salzburg and Nuremberg Austria and Chondrometrics GmbH, Institute of Anatomy, Ainring (Germany); Boudreau, Robert [University of Pittsburgh, Department of Epidemiology, Graduate School of Public Health, Pittsburgh, PA (United States); Wang, Zhijie; Hannon, Michael J. [University of Pittsburgh and Pittsburgh VAHS, Division of Rheumatology and Clinical Immunology, Pittsburgh, PA (United States); Duryea, Jeff [Brigham and Women' s Hospital, Harvard Medical School, Boston, MA (United States); Guermazi, Ali [Boston University School of Medicine and Boston Imaging Core Lab (BICL), LLC, Boston, MA (United States); Roemer, Frank [Boston University School of Medicine and Boston Imaging Core Lab (BICL), LLC, Boston, MA (United States); University of Erlangen-Nuremberg, Department of Radiology, Erlangen (Germany); Nevitt, Michael [OAI Coordinating Ctr., UCSF, San Francisco, CA (United States); John, Markus R. [Novartis Pharma AG, Basel (Switzerland); Ladel, Christoph [Merck KGaA, Darmstadt (Germany); Sharma, Leena [Northwestern University, Department of Medicine, Feinberg School of Medicine, Chicago, IL (United States); Hunter, David J. [University Sydney, Royal North Shore Hospital and Institute of Bone and Joint Research, Kolling Institute, Sydney, NSW (Australia); Kwoh, C.K. [University of Arizona, Division of Rheumatology and the University of Arizona Arthritis Center, Tucson, AZ (United States); Collaboration: OAI Investigators

    2016-06-15

    To evaluate whether change in fixed-location measures of radiographic joint space width (JSW) and cartilage thickness by MRI predict knee replacement. Knees replaced between 36 and 60 months' follow-up in the Osteoarthritis Initiative were each matched with one control by age, sex and radiographic status. Radiographic JSW was determined from fixed flexion radiographs and subregional femorotibial cartilage thickness from 3 T MRI. Changes between the annual visit before replacement (T{sub 0}) and 2 years before T{sub 0} (T{sub -2}) were compared using conditional logistic regression. One hundred and nineteen knees from 102 participants (55.5 % women; age 64.2 ± 8.7 [mean ± SD] years) were studied. Fixed-location JSW change at 22.5 % from medial to lateral differed more between replaced and control knees (case-control [cc] OR = 1.57; 95 % CI: 1.23-2.01) than minimum medial JSW change (ccOR = 1.38; 95 % CI: 1.11-1.71). Medial femorotibial cartilage loss displayed discrimination similar to minimum JSW, and central tibial cartilage loss similar to fixed-location JSW. Location-independent thinning and thickening scores were elevated prior to knee replacement. Discrimination of structural progression between knee pre-placement cases versus controls was stronger for fixed-location than minimum radiographic JSW. MRI displayed similar discrimination to radiography and suggested greater simultaneous cartilage thickening and loss prior to knee replacement. (orig.)

  15. Direct Load Control by AC Frequency Modulation

    DEFF Research Database (Denmark)

    Douglass, Philip James; You, Shi

    2012-01-01

    from this technology because their low inertia. The paper proposes a operating procedure for utilizing DFCR loads for energy balancing, expanding DFCR’s well known role as a power balancing resource. The system operator can use DFCR for energy balancing by adjusting the frequency controller...

  16. Caffeine Does Not Modulate Inhibitory Control

    Science.gov (United States)

    Tieges, Zoe; Snel, Jan; Kok, Albert; Ridderinkhof, K. Richard

    2009-01-01

    The effects of a 3 mg/kg body weight (BW) dose of caffeine were assessed on behavioral indices of response inhibition. To meet these aims, we selected a modified AX version of the Continuous Performance Test (CPT), the stop task, and the flanker task. In three double-blind, placebo-controlled, within-subjects experiments, these tasks were…

  17. Modular microfluidic systems using reversibly attached PDMS fluid control modules

    Science.gov (United States)

    Skafte-Pedersen, Peder; Sip, Christopher G.; Folch, Albert; Dufva, Martin

    2013-05-01

    The use of soft lithography-based poly(dimethylsiloxane) (PDMS) valve systems is the dominating approach for high-density microscale fluidic control. Integrated systems enable complex flow control and large-scale integration, but lack modularity. In contrast, modular systems are attractive alternatives to integration because they can be tailored for different applications piecewise and without redesigning every element of the system. We present a method for reversibly coupling hard materials to soft lithography defined systems through self-aligning O-ring features thereby enabling easy interfacing of complex-valve-based systems with simpler detachable units. Using this scheme, we demonstrate the seamless interfacing of a PDMS-based fluid control module with hard polymer chips. In our system, 32 self-aligning O-ring features protruding from the PDMS fluid control module form chip-to-control module interconnections which are sealed by tightening four screws. The interconnection method is robust and supports complex fluidic operations in the reversibly attached passive chip. In addition, we developed a double-sided molding method for fabricating PDMS devices with integrated through-holes. The versatile system facilitates a wide range of applications due to the modular approach, where application specific passive chips can be readily attached to the flow control module.

  18. Toward Modular Soft Robotics: Proprioceptive Curvature Sensing and Sliding-Mode Control of Soft Bidirectional Bending Modules.

    Science.gov (United States)

    Luo, Ming; Skorina, Erik H; Tao, Weijia; Chen, Fuchen; Ozel, Selim; Sun, Yinan; Onal, Cagdas D

    2017-06-01

    Real-world environments are complex, unstructured, and often fragile. Soft robotics offers a solution for robots to safely interact with the environment and human coworkers, but suffers from a host of challenges in sensing and control of continuously deformable bodies. To overcome these challenges, this article considers a modular soft robotic architecture that offers proprioceptive sensing of pressure-operated bending actuation modules. We present integrated custom magnetic curvature sensors embedded in the neutral axis of bidirectional bending actuators. We describe our recent advances in the design and fabrication of these modules to improve the reliability of proprioceptive curvature feedback over our prior work. In particular, we study the effect of dimensional parameters on improving the linearity of curvature measurements. In addition, we present a sliding-mode controller formulation that drives the binary solenoid valve states directly, giving the control system the ability to hold the actuator steady without continuous pressurization and depressurization. In comparison to other methods, this control approach does not rely on pulse width modulation and hence offers superior dynamic performance (i.e., faster response rates). Our experimental results indicate that the proposed soft robotic modules offer a large range of bending angles with monotonic and more linear embedded curvature measurements, and that the direct sliding-mode control system exhibits improved bandwidth and a notable reduction in binary valve actuation operations compared to our earlier iterative sliding-mode controller.

  19. Two-mode dynamics in pulse-modulated control systems

    DEFF Research Database (Denmark)

    Zhusubaliyev, Z.T.; Yanochkina, O.O.; Mosekilde, Erik

    2010-01-01

    as an example the paper provides a survey of three new mechanisms of torus bifurcation that can be observed in pulse-modulated control systems. The paper concludes with a discussion of the influence that operation in the torus regimes will have on the efficiency of the converter......Pulse-modulated converter systems play an important role in modern power electronics. Systems of this type also deserve considerable theoretical interest because of the complex interplay they exhibit between ordinary (smooth) bifurcations and so-called border-collision bifurcations generated...... by the switching dynamics. Particularly interesting are the unusual transitions to torus dynamics, i.e., to a mode of behavior in which the regular switching dynamics is modulated by another oscillatory mode that may arise through instability in the feedback control. Using the model of a two-level DC/DC converter...

  20. PULSE MODULATION POWER AMPLIFIER WITH ENHANCED CASCADE CONTROL METHOD

    DEFF Research Database (Denmark)

    1998-01-01

    A digital switching power amplifier with Multivariable Enhanced Cascade Controlled (MECC) includes a modulator, a switching power stage and a low pass filter. In the first preferred embodiment an enhanced cascade control structure local to the switching power stage is added, characterised by havi...... and feedback path A to determine stable self-oscillating conditions. An implemented 250W example MECC digital power amplifier has proven superior performance in terms of audio performance (0.005 % distortion, 115 dB dynamic range) and efficiency (92 %).......A digital switching power amplifier with Multivariable Enhanced Cascade Controlled (MECC) includes a modulator, a switching power stage and a low pass filter. In the first preferred embodiment an enhanced cascade control structure local to the switching power stage is added, characterised by having...

  1. Wireline Equalization using Pulse-Width Modulation

    NARCIS (Netherlands)

    Schrader, J.H.R.

    2007-01-01

    Copper channels suffer from attenuation and dispersion, caused by the skin effect and dielectric loss. Furthermore, they suffer from reflections, caused by impedance discontinuities. As a consequence, the achievable bit rate is limited by intersymbol interference: neighboring symbols interfere with

  2. Assessment of an Average Controller for a DC/DC Converter via Either a PWM or a Sigma-Delta-Modulator

    Directory of Open Access Journals (Sweden)

    R. Silva-Ortigoza

    2014-01-01

    Full Text Available Sliding mode control is a discontinuous control technique that is, by its nature, appropriate for controlling variable structure systems, such as the switch regulated systems employed in power electronics. However, when designing control laws based on the average models of these systems a modulator is necessary for their experimental implementation. Among the most widely used modulators in power electronics are the pulse width modulation (PWM and, more recently, the sigma-delta-modulator (Σ-Δ-modulator. Based on the importance of achieving an appropriate implementation of average control laws and the relevance of the trajectory tracking task in DC/DC power converters, for the first time, this research presents the assessment of the experimental results obtained when one of these controllers is implemented through either a PWM or a Σ-Δ-modulator to perform such a task. A comparative assessment based on the integral square error (ISE index shows that, at frequencies with similar efficiency, the Σ-Δ-modulator provides a better tracking performance for the DC/DC Buck converter. In this paper, an average control based on differential flatness was used to perform the experiments. It is worth mentioning that a different trajectory tracking controller could have been selected for this research.

  3. Adaptive beam-width control of echolocation sounds by CF-FM bats, Rhinolophus ferrumequinum nippon, during prey-capture flight.

    Science.gov (United States)

    Matsuta, Naohiro; Hiryu, Shizuko; Fujioka, Emyo; Yamada, Yasufumi; Riquimaroux, Hiroshi; Watanabe, Yoshiaki

    2013-04-01

    The echolocation sounds of Japanese CF-FM bats (Rhinolophus ferrumequinum nippon) were measured while the bats pursued a moth (Goniocraspidum pryeri) in a flight chamber. Using a 31-channel microphone array system, we investigated how CF-FM bats adjust pulse direction and beam width according to prey position. During the search and approach phases, the horizontal and vertical beam widths were ±22±5 and ±13±5 deg, respectively. When bats entered the terminal phase approximately 1 m from a moth, distinctive evasive flight by G. pryeri was sometimes observed. Simultaneously, the bats broadened the beam widths of some emissions in both the horizontal (44% of emitted echolocation pulses) and vertical planes (71%). The expanded beam widths were ±36±7 deg (horizontal) and ±30±9 deg (vertical). When moths began evasive flight, the tracking accuracy decreased compared with that during the approach phase. However, in 97% of emissions during the terminal phase, the beam width was wider than the misalignment (the angular difference between the pulse and target directions). These findings indicate that bats actively adjust their beam width to retain the moving target within a spatial echolocation window during the final capture stages.

  4. Matlab Stability and Control Toolbox: Trim and Static Stability Module

    Science.gov (United States)

    Crespo, Luis G.; Kenny, Sean P.

    2006-01-01

    This paper presents the technical background of the Trim and Static module of the Matlab Stability and Control Toolbox. This module performs a low-fidelity stability and control assessment of an aircraft model for a set of flight critical conditions. This is attained by determining if the control authority available for trim is sufficient and if the static stability characteristics are adequate. These conditions can be selected from a prescribed set or can be specified to meet particular requirements. The prescribed set of conditions includes horizontal flight, take-off rotation, landing flare, steady roll, steady turn and pull-up/ push-over flight, for which several operating conditions can be specified. A mathematical model was developed allowing for six-dimensional trim, adjustable inertial properties, asymmetric vehicle layouts, arbitrary number of engines, multi-axial thrust vectoring, engine(s)-out conditions, crosswind and gyroscopic effects.

  5. Biometrically modulated collaborative control for an assistive wheelchair.

    Science.gov (United States)

    Urdiales, Cristina; Fernandez-Espejo, Blanca; Annicchiaricco, Roberta; Sandoval, Francisco; Caltagirone, Carlo

    2010-08-01

    To operate a wheelchair, people with severe physical disabilities may require assistance, which can be provided by robotization. However, medical experts report that an excess of assistance may lead to loss of residual skills, so that it is important to provide just the right amount of assistance. This work proposes a collaborative control system based on weighting the robot's and the user's commands by their respective efficiency to reactively obtain an emergent controller. Thus, the better the person operates, the more control he/she gains. Tests with volunteers have proven, though, that some users may require extra assistance when they become stressed. Hence, we propose a controller that can change the amount of support taking into account supplementary biometric data. In this work, we use an off-the-shelf wearable pulse oximeter. Experiments have demonstrated that volunteers could use our wheelchair in a more efficient way due to the proposed biometric modulated collaborative control.

  6. Production quality controls and geometric characterization of the IFMIF-RFQ modules via the usage of a Coordinate Measuring Machine

    Energy Technology Data Exchange (ETDEWEB)

    Ferrari, Luigi, E-mail: luigi.ferrari@lnl.infn.it [INFN-LNL Laboratori Nazionali di Legnaro, Legnaro (Italy); Palmieri, Antonio [INFN-LNL Laboratori Nazionali di Legnaro, Legnaro (Italy); Pepato, Adriano; Prevedello, Alessandro; Dima, Razvan; Udup, Emil [INFN-Sezione di Padova, Padova (Italy)

    2017-02-15

    Highlights: • The production phases of the IFMIF-RFQ Modules is introduced. • Metrological controls through production are described and some results reported. • Radio-Frequency test is introduced by using geometric considerations. • Results from metrology and RF test are compared. • Acceptance of the modules has been guaranteed from that comparison. - Abstract: The RFQ of the IFMIF/EVEDA project (Pérez et al., 2015) is a 9.8 m long cavity able to accelerate a 125 mA deuteron beam from the input energy of 50 keV/u to the output energy of 2.5 MeV/u. Such RFQ operates at the frequency of 175 MHz and is composed of 18 mechanical modules approximately 0.55 long each (Pepato et al., 2010) . The RFQ realization involves the I.N.F.N. Sections of Padova, Torino and Bologna, as well as the Legnaro National Laboratories (L.N.L.). The metrological measurements via CMM (Coordinate Measuring Machine) provided to be a very effective tool both for quality controls along the RFQ production phases and in the reconstruction of the cavity geometric profile for each RFQ module. The scans in the most sensitive regions with respect to RF frequency, such as modulation, tips, base-vane width and vessel height provided the values of the cavity deviations from nominal geometry to be compared with design physic-driven tolerances and with RF measurements. Moreover, the comparison between mechanical and RF measurements suggests a methodology for the geometric reconstruction of the cavity axis and determines the final machining of the end surfaces of each module in view of the coupling with the adjacent ones. In this paper a detailed description of the metrological procedures and tests and of the RFQ along its production and assembly phases will be given and it will be shown that the adopted procedure allowed the attainment of the tuning range specifications for each RFQ module.

  7. Breaking the limits of line width and aspect ratio for inkjet printed conductive lines by controlling post-deposition ink contraction

    NARCIS (Netherlands)

    Teunissen, P.; Abbel, R.J.; Michels, J.J.; Groen, P.

    2014-01-01

    Electrically conductive structures comprising both narrow line widths and high aspect ratios are indispensable components of many electronic devices. Producing them reliably on an industrial scale by inkjet printing of metal-based inks is a serious challenge. Firstly, due to spreading of the ink on

  8. Color control through FRET efficiency modulation using CDI (Conference Presentation)

    Science.gov (United States)

    Wolowelsky, Karni; Guyes, Eric; Rubin, Shimon; Suss, Matthew; Bercovici, Moran; Rotschild, Carmel

    2017-02-01

    Although much progress was made in light emitting devices, the ability to electrically control their spectral emission remains limited. We will present a novel approach and experimental results for dynamic color control, by electrically modulating the non-radiative Forster resonance energy transfer (FRET) efficiency between donor and acceptor dyes in a solution. FRET efficiency depends on the 6th power of the distance between donor and acceptor dye molecules, and thus, it is sensitive to variations in acceptor's concentration. Controlled acceptor concentrations could be achieved by attracting or repelling ionic dyes from the electrodes using a capacitive deionization (CDI) cell, with high surface area porous electrodes. This approach to dynamic color control may open new directions in 100% fill-factor displays, and can be expanded to energy saving applications such as controlling building's external wall emissivity. We studied the modulation of a single dye emission using a CDI cell with negatively charged Fluorescein Sodium Salt in aquatic solution. Photoluminescence was measured along few charging-discharging CDI cycles and showed the ability to control extensive optical response through CDI. We experimented with two types of FRET-pair dyes: a) anion-cation, where the acceptor and the donor ions are oppositely charged, and b) zwitterion and ion, where the donor is neutral. We found that electrical control on FRET in aquatic solution is weak, due to hydrophobic attractive interaction between the acceptor and the donor. In order to avoid this effect, we are experimenting FRET control in organic solvents. These results will be presented in the talk.

  9. Optimal Backlight Modulation With Crosstalk Control in Stereoscopic Display

    DEFF Research Database (Denmark)

    Jiao, Liangbao; Shu, Xiao; Cheng, Yong

    2014-01-01

    Crosstalk between the left-eye and right-eye images is one of the main artifacts affecting the visual quality of stereoscopic liquid crystal display (LCD) systems. In this paper, a novel technique, called Optimal Backlight Modulation (OBM), is proposed to reduce crosstalk by taking the advantage....... A simple closed-form approximation of the optimization problem can be easily employed and solved in real time on LCD control hardware. Simulation results show that the proposed OBM algorithm provides the same or higher luminance while reducing the crosstalk by 60% compared with the other tested methods....

  10. Decoupling Control Design for the Module Suspension Control System in Maglev Train

    Directory of Open Access Journals (Sweden)

    Guang He

    2015-01-01

    Full Text Available An engineering oriented decoupling control method for the module suspension system is proposed to solve the coupling issues of the two levitation units of the module in magnetic levitation (maglev train. According to the format of the system transfer matrix, a modified adjoint transfer matrix based decoupler is designed. Then, a compensated controller is obtained in the light of a desired close loop system performance. Optimization between the performance index and robustness index is also carried out to determine the controller parameters. However, due to the high orders and complexity of the obtained resultant controller, model reduction method is adopted to get a simplified controller with PID structure. Considering the modeling errors of the module suspension system as the uncertainties, experiments have been performed to obtain the weighting function of the system uncertainties. By using this, the robust stability of the decoupled module suspension control system is checked. Finally, the effectiveness of the proposed decoupling design method is validated by simulations and physical experiments. The results illustrate that the presented decoupling design can result in a satisfactory decoupling and better dynamic performance, especially promoting the reliability of the suspension control system in practical engineering application.

  11. Transcranial extracellular impedance control (tEIC modulates behavioral performances.

    Directory of Open Access Journals (Sweden)

    Ayumu Matani

    Full Text Available Electric brain stimulations such as transcranial direct current stimulation (tDCS, transcranial random noise stimulation (tRNS, and transcranial alternating current stimulation (tACS electrophysiologically modulate brain activity and as a result sometimes modulate behavioral performances. These stimulations can be viewed from an engineering standpoint as involving an artificial electric source (DC, noise, or AC attached to an impedance branch of a distributed parameter circuit. The distributed parameter circuit is an approximation of the brain and includes electric sources (neurons and impedances (volume conductors. Such a brain model is linear, as is often the case with the electroencephalogram (EEG forward model. Thus, the above-mentioned current stimulations change the current distribution in the brain depending on the locations of the electric sources in the brain. Now, if the attached artificial electric source were to be replaced with a resistor, or even a negative resistor, the resistor would also change the current distribution in the brain. In light of the superposition theorem, which holds for any linear electric circuit, attaching an electric source is different from attaching a resistor; the resistor affects each active electric source in the brain so as to increase (or decrease in some cases of a negative resistor the current flowing out from each source. From an electrophysiological standpoint, the attached resistor can only control the extracellular impedance and never causes forced stimulation; we call this technique transcranial extracellular impedance control (tEIC. We conducted a behavioral experiment to evaluate tEIC and found evidence that it had real-time enhancement and depression effects on EEGs and a real-time facilitation effect on reaction times. Thus, tEIC could be another technique to modulate behavioral performance.

  12. Modulation and control of matrix converter for aerospace application

    Science.gov (United States)

    Kobravi, Keyhan

    In the context of modern aircraft systems, a major challenge is power conversion to supply the aircraft's electrical instruments. These instruments are energized through a fixed-frequency internal power grid. In an aircraft, the available sources of energy are a set of variable-speed generators which provide variable-frequency ac voltages. Therefore, to energize the internal power grid of an aircraft, the variable-frequency ac voltages should be converted to a fixed-frequency ac voltage. As a result, an ac to ac power conversion is required within an aircraft's power system. This thesis develops a Matrix Converter to energize the aircraft's internal power grid. The Matrix Converter provides a direct ac to ac power conversion. A major challenge of designing Matrix Converters for aerospace applications is to minimize the volume and weight of the converter. These parameters are minimized by increasing the switching frequency of the converter. To design a Matrix Converter operating at a high switching frequency, this thesis (i) develops a scheme to integrate fast semiconductor switches within the current available Matrix Converter topologies, i.e., MOSFET-based Matrix Converter, and (ii) develops a new modulation strategy for the Matrix Converter. This Matrix Converter and the new modulation strategy enables the operation of the converter at a switching-frequency of 40kHz. To provide a reliable source of energy, this thesis also develops a new methodology for robust control of Matrix Converter. To verify the performance of the proposed MOSFET-based Matrix Converter, modulation strategy, and control design methodology, various simulation and experimental results are presented. The experimental results are obtained under operating condition present in an aircraft. The experimental results verify the proposed Matrix Converter provides a reliable power conversion in an aircraft under extreme operating conditions. The results prove the superiority of the proposed Matrix

  13. Bilingualism modulates dual mechanisms of cognitive control: Evidence from ERPs.

    Science.gov (United States)

    Morales, Julia; Yudes, Carolina; Gómez-Ariza, Carlos J; Bajo, M Teresa

    2015-01-01

    Recent behavioral findings with the AX-Continous Performance Task (AX-CPT; Morales et al., 2013) show that bilinguals only outperform monolinguals under conditions that require the highest adjustment between monitoring (proactive) and inhibitory (reactive) control, which supports the idea that bilingualism modulates the coordination of different control mechanisms. In an ERP experiment we aimed to further investigate the role that bilingualism plays in the dynamic combination of proactive and reactive control in the AX-CPT. Our results strongly indicate that bilingualism facilitates an effective adjustment between both components of cognitive control. First, we replicated previous behavioral results. Second, ERP components indicated that bilingualism influences the conflict monitoring, response inhibition and error monitoring components of control (as indexed by the N2 and P3a elicited by the probe and the error-related negativity following incorrect responses, respectively). Thus, bilinguals exerted higher reactive control than monolinguals but only when they needed to overcome the competing cue-information. These findings join others in suggesting that a better understanding of the cognitive benefits of bilingualism may require consideration of a multi-component perspective. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. The spatial light modulator for controlling beam deflection

    Science.gov (United States)

    Zang, Xu; Hu, Wengang; Wu, Dongsheng

    2017-10-01

    In this paper, according to the principle of non-mechanical structure, the liquid crystal spatial light modulator is used as the modulation device, and a new way to realize the deflection control of the beam is proposed. The theoretical model of beam deflection control is established. The relationship between the radius of the first ring of the Fresnel lens and its corresponding focal length is analyzed. The range and accuracy of the beam deflection angle are analyzed under different center radii. The relationship between the deflection angle of the beam with the same displacement distance at different center radii is analyzed. The relationship between the beam deflection and the fresnel phase diagram size and displacement factor is obtained. Within a certain range, the smaller the radius of the first ring of loaded fresnel phase map, the greater the deflection angle. According to the experiment expected to reduce the phase map radius, with the follow-up optical path should be able to improve the scope of beam scanning.

  15. Controller Design for Direct Torque Controlled Space Vector Modulated (DTC-SVM) Induction Motor Drives

    DEFF Research Database (Denmark)

    Zelechowski, M.; Kazmierkowski, M.P.; Blaabjerg, Frede

    2005-01-01

    In this paper two different methods of PI controllers for direct torque controlled-space vector modulated induction motor drives have been studied. The first one is simple method based only on symmetric optimum criterion. The second approach takes into account the full model of induction motor...... including rotor voltage equation and uses root locus method. Some simulated and experimental oscillograms that illustrate properties of the presented controller design methods are shown....

  16. Engine Performance (Section C: Emission Control Systems). Auto Mechanics Curriculum Guide. Module 3. Instructor's Guide.

    Science.gov (United States)

    Rains, Larry

    This engine performance (emission control systems) module is one of a series of competency-based modules in the Missouri Auto Mechanics Curriculum Guide. Topics of this module's five units are: positive crankcase ventilation (PCV) and evaporative emission control systems; exhaust gas recirculation (EGR); air injection and catalytic converters;…

  17. Double Modulation Scheme for Switching Mixers Controlled by Sigma-Delta Modulators

    DEFF Research Database (Denmark)

    Nielsen, Per Asbeck; Fallesen, Carsten

    1998-01-01

    A new method of modulating a signal, using sigma delta modulation in conjunction with switching- and sub-sampling mixers, is presented. Besides the normal functionality provided by the mixer, an additional mixing or modulation function can be achieved with a small modification to the existing mixer...

  18. Programmable logic controller optical fibre sensor interface module

    Science.gov (United States)

    Allwood, Gary; Wild, Graham; Hinckley, Steven

    2011-12-01

    Most automated industrial processes use Distributed Control Systems (DCSs) or Programmable Logic Controllers (PLCs) for automated control. PLCs tend to be more common as they have much of the functionality of DCSs, although they are generally cheaper to install and maintain. PLCs in conjunction with a human machine interface form the basis of Supervisory Control And Data Acquisition (SCADA) systems, combined with communication infrastructure and Remote Terminal Units (RTUs). RTU's basically convert different sensor measurands in to digital data that is sent back to the PLC or supervisory system. Optical fibre sensors are becoming more common in industrial processes because of their many advantageous properties. Being small, lightweight, highly sensitive, and immune to electromagnetic interference, means they are an ideal solution for a variety of diverse sensing applications. Here, we have developed a PLC Optical Fibre Sensor Interface Module (OFSIM), in which an optical fibre is connected directly to the OFSIM located next to the PLC. The embedded fibre Bragg grating sensors, are highly sensitive and can detect a number of different measurands such as temperature, pressure and strain without the need for a power supply.

  19. Synthetic Space Vector Modulation

    Science.gov (United States)

    2013-06-01

    controller. The VSI controller has traditionally been operated by hardwired pulse-width modulation (PWM) or the use of a programmable microprocessor ...frequency. The primary difference between SVM and synthetic SVM is the implementation strategy of software versus inexpensive hardware, respectively. A...resistors and capacitors. There are no microcontrollers or FPGAs necessary to produce Alt-Rev SVM. F. DUAL OUTPUT VARIABLE FREQUENCY OSCILLATOR After

  20. Remotely Controlled Mixers for Light Microscopy Module (LMM) Colloid Samples

    Science.gov (United States)

    Kurk, Michael A. (Andy)

    2015-01-01

    Developed by NASA Glenn Research Center, the LMM aboard the International Space Station (ISS) is enabling multiple biomedical science experiments. Techshot, Inc., has developed a series of colloid specialty cell systems (C-SPECS) for use in the colloid science experiment module on the LMM. These low-volume mixing devices will enable uniform particle density and remotely controlled repetition of LMM colloid experiments. By automating the experiment process, C-SPECS allow colloid samples to be processed more quickly. In addition, C-SPECS will minimize the time the crew will need to spend on colloid experiments as well as eliminate the need for multiple and costly colloid samples, which are expended after a single examination. This high-throughput capability will lead to more efficient and productive use of the LMM. As commercial launch vehicles begin routine visits to the ISS, C-SPECS could become a significant means to process larger quantities of high-value materials for commercial customers.

  1. Divisive gain modulation of motoneurons by inhibition optimizes muscular control

    DEFF Research Database (Denmark)

    Vestergaard, Mikkel; Berg, Rune W.

    2015-01-01

    When using muscles, the precision with which force is delivered is as important as the delivery of force itself. Force is regulated by both the number of recruited motoneurons and their spike frequency. While it is known that the recruitment is ordered to reduce variability in force, it remains...... unclear whether the motoneuron gain, i.e., the slope of the transformation between synaptic input and spiking output, is also modulated to reduce variability in force. To address this issue, we use turtle hindlimb scratching as a model for fine motor control, since this behavior involves precise limb...... movement to rub the location of somatic nuisance touch. We recorded intracellularly from motoneurons in a reduced preparation where the limbs were removed to increase mechanical stability and the motor nerve activity served as a surrogate for muscle force. We found that not only is the gain of motoneurons...

  2. Automated force controller for amplitude modulation atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Miyagi, Atsushi, E-mail: atsushi.miyagi@inserm.fr, E-mail: simon.scheuring@inserm.fr; Scheuring, Simon, E-mail: atsushi.miyagi@inserm.fr, E-mail: simon.scheuring@inserm.fr [U1006 INSERM, Université Aix-Marseille, Parc Scientifique et Technologique de Luminy, 163 Avenue de Luminy, 13009 Marseille (France)

    2016-05-15

    Atomic Force Microscopy (AFM) is widely used in physics, chemistry, and biology to analyze the topography of a sample at nanometer resolution. Controlling precisely the force applied by the AFM tip to the sample is a prerequisite for faithful and reproducible imaging. In amplitude modulation (oscillating) mode AFM, the applied force depends on the free and the setpoint amplitudes of the cantilever oscillation. Therefore, for keeping the applied force constant, not only the setpoint amplitude but also the free amplitude must be kept constant. While the AFM user defines the setpoint amplitude, the free amplitude is typically subject to uncontrollable drift, and hence, unfortunately, the real applied force is permanently drifting during an experiment. This is particularly harmful in biological sciences where increased force destroys the soft biological matter. Here, we have developed a strategy and an electronic circuit that analyzes permanently the free amplitude of oscillation and readjusts the excitation to maintain the free amplitude constant. As a consequence, the real applied force is permanently and automatically controlled with picoNewton precision. With this circuit associated to a high-speed AFM, we illustrate the power of the development through imaging over long-duration and at various forces. The development is applicable for all AFMs and will widen the applicability of AFM to a larger range of samples and to a larger range of (non-specialist) users. Furthermore, from controlled force imaging experiments, the interaction strength between biomolecules can be analyzed.

  3. Probabilistic Analysis of Crack Width

    Directory of Open Access Journals (Sweden)

    J. Marková

    2000-01-01

    Full Text Available Probabilistic analysis of crack width of a reinforced concrete element is based on the formulas accepted in Eurocode 2 and European Model Code 90. Obtained values of reliability index b seem to be satisfactory for the reinforced concrete slab that fulfils requirements for the crack width specified in Eurocode 2. However, the reliability of the slab seems to be insufficient when the European Model Code 90 is considered; reliability index is less than recommended value 1.5 for serviceability limit states indicated in Eurocode 1. Analysis of sensitivity factors of basic variables enables to find out variables significantly affecting the total crack width.

  4. A deterministic width function model

    Directory of Open Access Journals (Sweden)

    C. E. Puente

    2003-01-01

    Full Text Available Use of a deterministic fractal-multifractal (FM geometric method to model width functions of natural river networks, as derived distributions of simple multifractal measures via fractal interpolating functions, is reported. It is first demonstrated that the FM procedure may be used to simulate natural width functions, preserving their most relevant features like their overall shape and texture and their observed power-law scaling on their power spectra. It is then shown, via two natural river networks (Racoon and Brushy creeks in the United States, that the FM approach may also be used to closely approximate existing width functions.

  5. High speed turning of compacted graphite iron using controlled modulation

    Science.gov (United States)

    Stalbaum, Tyler Paul

    Compacted graphite iron (CGI) is a material which emerged as a candidate material to replace cast iron (CI) in the automotive industry for engine block castings. Its thermal and mechanical properties allow the CGI-based engines to operate at higher cylinder pressures and temperatures than CI-based engines, allowing for lower fuel emissions and increased fuel economy. However, these same properties together with the thermomechanical wear mode in the CGI-CBN system result in poor machinability and inhibit CGI from seeing wide spread use in the automotive industry. In industry, machining of CGI is done only at low speeds, less than V = 200 m/min, to avoid encountering rapid wear of the cutting tools during cutting. Studies have suggested intermittent cutting operations such as milling suffer less severe tool wear than continuous cutting. Furthermore, evidence that a hard sulfide layer which forms over the cutting edge in machining CI at high speeds is absent during machining CGI is a major factor in the difference in machinability of these material systems. The present study addresses both of these issues by modification to the conventional machining process to allow intermittent continuous cutting. The application of controlled modulation superimposed onto the cutting process -- modulation-assisted machining (MAM) -- is shown to be quite effective in reducing the wear of cubic boron nitride (CBN) tools when machining CGI at high machining speeds (> 500 m/min). The tool life is at least 20 times greater than found in conventional machining of CGI. This significant reduction in wear is a consequence of reduction in the severity of the tool-work contact conditions with MAM. The propensity for thermochemical wear of CBN is thus reduced. It is found that higher cutting speed (> 700 m/min) leads to lower tool wear with MAM. The MAM configuration employing feed-direction modulation appears feasible for implementation at high speeds and offers a solution to this challenging

  6. Pulsed klystrons with feedback controlled mod-anode modulators

    Energy Technology Data Exchange (ETDEWEB)

    Reass, William A [Los Alamos National Laboratory; Baca, David M [Los Alamos National Laboratory; Jerry, Davis L [Los Alamos National Laboratory; Rees, Daniel E [Los Alamos National Laboratory

    2009-01-01

    This paper describes a fast rise and fall, totem-pole mod-anode modulators for klystron application. Details of these systems as recently installed utilizing a beam switch tube ''on-deck'' and a planar triode ''off-deck'' in a grid-catch feedback regulated configuration will be provided. The grid-catch configuration regulates the klystron mod-anode voltage at a specified set-point during switching as well as providing a control mechanism that flat-top regulates the klystron beam current during the pulse. This flat-topped klystron beam current is maintained while the capacitor bank droops. In addition, we will review more modern on-deck designs using a high gain, high voltage planar triode as a regulating and switching element. These designs are being developed, tested, and implemented for the Los Alamos Neutron Science Center (LANSCE) accelerator refurbishment project, ''LANSCE-R''. An advantage of the planar triode is that the tube can be directly operated with solid state linear components and provides for a very compact design. The tubes are inexpensive compared to stacked semiconductor switching assemblies and also provide a linear control capability. Details of these designs are provided as well as operational and developmental results.

  7. Cues of control modulate the ascription of object ownership.

    Science.gov (United States)

    Scorolli, Claudia; Borghi, Anna M; Tummolini, Luca

    2017-06-06

    Knowing whether an object is owned and by whom is essential to avoid costly conflicts. We hypothesize that everyday interactions around objects are influenced by a minimal sense of object ownership grounded on respect of possession. In particular, we hypothesize that tracking object ownership can be influenced by any cue that predicts the establishment of individual physical control over objects. To test this hypothesis we used an indirect method to determine whether visual cues of physical control like spatial proximity to an object, temporal priority in seeing it, and touching it influence this minimal sense of object ownership. In Experiment 1 participants were shown a neutral object located on a table, in the reaching space of one of two characters. In Experiment 2 one character was the first to find the object then another character appeared and saw the object. In Experiments 3 and 4, spatial proximity, temporal priority, and touch are pitted against each other to assess their relative weight. After having seen the scenes, participants were required to judge the sensibility of sentences in which ownership of the object was ascribed to one of the two characters. Responses were faster when the objects were located in the reaching space of the character to whom ownership was ascribed in the sentence and when ownership was ascribed to the character who was the first to find the object. When contrasting the relevant cues, results indicate that touch is stronger than temporal priority in modulating the ascription of object ownership. However, all these effects were also influenced by contextual social cues like the gender of both characters and participants, the presence of a third-party observer, and the co-presence of characters. Consistently with our hypothesis, results indicate that many different cues of physical control influence the ascription of ownership in daily social contexts.

  8. Respiratory modulation and baroreflex control of heart rate in space

    Science.gov (United States)

    Verheyden, Bart; Couckuyt, Kurt; Liu, Jiexin; Aubert, Andre

    During everyday life, gravity constantly stresses the human circulation by diminishing venous return in the upright position. This induces baroreflex-mediated cardiovascular adjustments that are aimed to prevent the blood pressure from falling. In weightlessness, gravitational pressure gradients do not arise in the circulation so that baroreflex function remains chronically unchallenged. This may contribute to the development of post spaceflight orthostatic intolerance. The purpose of this study was to evaluate respiratory modulation and baroreflex control of heart rate after a week of weightlessness in space. We tested the hypothesis that cardiovascular control in space will be similar to the baseline supine condition on Earth. We studied nine male cosmonauts during seven different space missions aboard the ISS (age 40 - 52 yrs, height 1.69 - 1.85 m, weight 67 - 90 kg). Data collection was performed between 30 and 45 days before launch in the standing and supine positions, and after 8 days in space. Cosmonauts were carefully trained to perform in-flight data collection by themselves. They were instructed to pace their breathing to a fixed rate of 12 breaths per minute (0.2 Hz) for a total duration of 3 minutes. The electrocardiogram and beat-by-beat finger arterial blood pressure were recorded at 1-kHz sample rate. Respiratory rate was evaluated using an abdominal pressure sensor. We used power spectral analysis to calculate respiratory sinus arrhythmia (RSA) as well as the low-frequency (0.04 - 0.15 Hz) powers of spontaneous oscillations in heart rate and systolic blood pressure. Baroreflex sensitivity (BRS) was estimated in the time domain using cross-correlation analysis. As expected, there was a rise in heart rate upon assuming the standing position before space- flight (59 ± 6 to 79 ± 11 beats per min; p ¡ 0.001). This was accompanied by an increase in mean arterial blood pressure (84 ± 6 to 93 ± 6 mmHg; p ¡ 0.001). Standing up further induced a marked

  9. Cognitive control modulates attention to food cues: Support for the control readiness model of self-control.

    Science.gov (United States)

    Kleiman, Tali; Trope, Yaacov; Amodio, David M

    2016-12-01

    Self-control in one's food choices often depends on the regulation of attention toward healthy choices and away from temptations. We tested whether selective attention to food cues can be modulated by a newly developed proactive self-control mechanism-control readiness-whereby control activated in one domain can facilitate control in another domain. In two studies, we elicited the activation of control using a color-naming Stroop task and tested its effect on attention to food cues in a subsequent, unrelated task. We found that control readiness modulates both overt attention, which involves shifts in eye gaze (Study 1), and covert attention, which involves shift in mental attention without shifting in eye gaze (Study 2). We further demonstrated that individuals for whom tempting food cues signal a self-control problem (operationalized by relatively higher BMI) were especially likely to benefit from control readiness. We discuss the theoretical contributions of the control readiness model and the implications of our findings for enhancing proactive self-control to overcome temptation in food choices. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Optical waveguide device with an adiabatically-varying width

    Energy Technology Data Exchange (ETDEWEB)

    Watts,; Michael R. (Albuquerque, NM), Nielson; Gregory, N [Albuquerque, NM

    2011-05-10

    Optical waveguide devices are disclosed which utilize an optical waveguide having a waveguide bend therein with a width that varies adiabatically between a minimum value and a maximum value of the width. One or more connecting members can be attached to the waveguide bend near the maximum value of the width thereof to support the waveguide bend or to supply electrical power to an impurity-doped region located within the waveguide bend near the maximum value of the width. The impurity-doped region can form an electrical heater or a semiconductor junction which can be activated with a voltage to provide a variable optical path length in the optical waveguide. The optical waveguide devices can be used to form a tunable interferometer (e.g. a Mach-Zehnder interferometer) which can be used for optical modulation or switching. The optical waveguide devices can also be used to form an optical delay line.

  11. Improvement The Transmission Efficiency For Wireless Packet Communication Systems Using Automatic Control for power And Time Slot Width Of Slotted Non persistent ISMA Protocol

    Directory of Open Access Journals (Sweden)

    Saad M. Hardan

    2013-05-01

    Full Text Available In packed communication systems which use a protocol, the protocol should perform the allocation of channels such that the transmission channel is used efficiently. Efficiency is usually measured in terms of channel throughput and the average transmission  delay. The Slotted Nonpersistent ISMA protocol is one of random access protocols used in packed communication systems. In this research a Slotted Nonpersistent ISMA protocol Model with automatic control for power and time slot is proposed. the suggested algorithm enable the base station(access point to control  the protocol time slot length and  transmission power in a dynamic way to control the normalized propagation delay d and to maintain all the uplink signals in the limit of captured power threshold (capture ratio in order to control the  throughput and the average transmission delay of the communication system by an automatic method. the computer simulation results  confirm the activity of the  proposed algorithm for increasing the  throughput and decreasing the average transmission delay by an accepted ratios.

  12. Algorithms and software for modules of automatic neurocomputer control of smart electromechanical system such as hexapods

    Science.gov (United States)

    Romanchuk, V. A.

    2015-10-01

    The article discusses issues in developing algorithms and software for specialized computing devices based on neuroprocessors, to be used in automatic control of electric- mechanical system modules (in this case study, a hexapod) in a mode that is close to real-time. The practical implementation employed an NM6406 neuroprocessor based on an MC 51.03 tool module and an MB 77.07 microcomputer, developed by the Module Research Centre.

  13. EPICS IOC module development and implementation for the ISTTOK machine subsystem operation and control

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Paulo, E-mail: pricardofc@ipfn.ist.utl.pt [Associacao EURATOM/IST, Instituto de Plasmas e Fusao Nuclear-Laboratorio Associado, Instituto Superior Tecnico, P-1049-001 Lisboa (Portugal); Duarte, Andre; Pereira, Tiago; Carvalho, Bernardo; Sousa, Jorge; Fernandes, Horacio [Associacao EURATOM/IST, Instituto de Plasmas e Fusao Nuclear-Laboratorio Associado, Instituto Superior Tecnico, P-1049-001 Lisboa (Portugal); Correia, Carlos [Grupo de Electronica e Instrumentacao-Centro de Instrumentacao, Departamento de Fisica, Universidade de Coimbra, P-3004-516 Coimbra (Portugal); Goncalves, Bruno; Varandas, Carlos [Associacao EURATOM/IST, Instituto de Plasmas e Fusao Nuclear-Laboratorio Associado, Instituto Superior Tecnico, P-1049-001 Lisboa (Portugal)

    2011-10-15

    This paper presents a developed, tested and integrated EPICS IOC (I/O controller) module solution for the ISTTOK tokamak machine operation and control for the vacuum and gas injection systems. The work is organized in two software layers which communicate through a serial RS-232 communication protocol. The first software layer is an EPICS IOC module running as a computer server application capable of receiving requests from remote or local clients providing driver interface to the system by forwarding requested commands and receiving system and control operation status. The second software layer is the firmware running in Microchip dsPIC microcontroller modules which performs the interface from RS-232 optical fiber serial protocol to EPICS IOC module. The dsPIC module communicates to the ISTTOK tokamak sensors and actuators via RS-485 and is programmed with a new protocol developed for this purpose that allows EPICS IOC module command sending/receiving, machine operation control and monitoring and system status information. Communication between EPICS IOC module and clients is achieved via a TCP/IP and UDP protocol referred as Channel Access. In addition, the EPICS IOC module provides user client applications access allowing operators to perform remote or local monitoring, operation and control.

  14. Digital Pulse Modulation Amplifier (PMA) systems based on PEDEC control

    DEFF Research Database (Denmark)

    Nielsen, Karsten

    1999-01-01

    The paper extends previous research and presents a suite of novel high efficiency digital PMA topologies based on Pulse Edge Delay Error Correction (PEDEC). The practical results are very encouraging, showing that digital modulator performance is maintained throughout the subsequent power...... conversion. The topologies are believed to be the first implemented digital PMA systems including effective power stage error correction....

  15. How Character Complexity Modulates Eye Movement Control in Chinese Reading

    Science.gov (United States)

    Ma, Guojie; Li, Xingshan

    2015-01-01

    This empirical study examined whether the visual complexities of the first and second characters in two-character words play similar roles in modulating the fixation time and saccade target selection during un-spaced Chinese reading. Consistent with prior research, words with low-complexity characters were fixated for shorter times than words with…

  16. Development of Active External Network Topology Module for Floodlight SDN Controller

    Directory of Open Access Journals (Sweden)

    A. A. Noskov

    2015-01-01

    Full Text Available Traditional network architecture is inflexible and complicated. This observation has led to a paradigm shift towards software-defined networking (SDN, where network management level is separated from data forwarding level. This change was made possible by control plane transfer from the switching equipment to software modules that run on a dedicated server, called the controller (or network operating system, or network applications, that work with this controller. Methods of representation, storage and communication interfaces with network topology elements are the most important aspects of network operating systems available to SDN user because performance of some key controller modules is heavily dependent on internal representation of the network topology. Notably, firewall and routing modules are examples of such modules. This article describes the methods used for presentation and storage of network topologies, as well as interface to the corresponding Floodlight modules. An alternative algorithm has been suggested and developed for message exchange conveying network topology alterations between the controller and network applications. Proposed algorithm makes implementation of module alerting based on subscription to the relevant events. API for interaction between controller and network applications has been developed. This algorithm and API formed the base for Topology Tracker module capable to inform network applications about the changes that had occurred in the network topology and also stores compact representation of the network to speed up the interaction process.

  17. DSP Based Direct Torque Control of Permanent Magnet Synchronous Motor (PMSM) using Space Vector Modulation (DTC-SVM)

    DEFF Research Database (Denmark)

    Swierczynski, Dariusz; Kazmierkowski, Marian P.; Blaabjerg, Frede

    2002-01-01

    DSP Based Direct Torque Control of Permanent Magnet Synchronous Motor (PMSM) using Space Vector Modulation (DTC-SVM)......DSP Based Direct Torque Control of Permanent Magnet Synchronous Motor (PMSM) using Space Vector Modulation (DTC-SVM)...

  18. [Statistical process control applied to intensity modulated radiotherapy pretreatment controls with portal dosimetry].

    Science.gov (United States)

    Villani, N; Gérard, K; Marchesi, V; Huger, S; François, P; Noël, A

    2010-06-01

    The first purpose of this study was to illustrate the contribution of statistical process control for a better security in intensity modulated radiotherapy (IMRT) treatments. This improvement is possible by controlling the dose delivery process, characterized by pretreatment quality control results. So, it is necessary to put under control portal dosimetry measurements (currently, the ionisation chamber measurements were already monitored by statistical process control thanks to statistical process control tools). The second objective was to state whether it is possible to substitute ionisation chamber with portal dosimetry in order to optimize time devoted to pretreatment quality control. At Alexis-Vautrin center, pretreatment quality controls in IMRT for prostate and head and neck treatments were performed for each beam of each patient. These controls were made with an ionisation chamber, which is the reference detector for the absolute dose measurement, and with portal dosimetry for the verification of dose distribution. Statistical process control is a statistical analysis method, coming from industry, used to control and improve the studied process quality. It uses graphic tools as control maps to follow-up process, warning the operator in case of failure, and quantitative tools to evaluate the process toward its ability to respect guidelines: this is the capability study. The study was performed on 450 head and neck beams and on 100 prostate beams. Control charts, showing drifts, both slow and weak, and also both strong and fast, of mean and standard deviation have been established and have shown special cause introduced (manual shift of the leaf gap of the multileaf collimator). Correlation between dose measured at one point, given with the EPID and the ionisation chamber has been evaluated at more than 97% and disagreement cases between the two measurements were identified. The study allowed to demonstrate the feasibility to reduce the time devoted to

  19. Performance Investigation of Air Velocity Effects on PV Modules under Controlled Conditions

    Directory of Open Access Journals (Sweden)

    Muzaffar Ali

    2017-01-01

    Full Text Available Junction temperature of PV modules is one of the key parameters on which the performance of PV modules depends. In the present work, an experimental investigation was carried out to analyze the effects of air velocity on the performance of two PV modules, that is, monocrystalline silicon and polycrystalline silicon under the controlled conditions of a wind tunnel in the presence of an artificial solar simulator. The parameters investigated include the surface temperature variation, power output, and efficiency of PV modules under varying air velocity from near zero (indoor lab. conditions to 15 m/s. Additionally, the results were also determined at two different module angular positions: at 0° angle, that is, parallel to air direction and at 10° angle with the direction of coming air to consider the effects of tilt angles. Afterwards, the thermal analysis of the modules was performed using Ansys-Fluent in which junction temperature and heat flux of modules were determined by applying appropriate boundary conditions, such as air velocity, heat flux, and solar radiation. Finally, the numerical results are compared with the experiment in terms of junction temperatures of modules and good agreement was found. Additionally, the results showed that the maximum module temperature drops by 17.2°C and the module efficiency and power output increased from 10 to 12% with increasing air velocity.

  20. Coordination Control of SMR-Based NSSS Modules Integrated by Feedwater Distribution

    Science.gov (United States)

    Dong, Zhe; Song, Maoxuan; Huang, Xiaojin; Zhang, Zuoyi; Wu, Zongxin

    2016-10-01

    Due to its strong safety feature, the small modular reactor whose electric output is no more than 300MWe has been seen as a promising trend in nuclear engineering. By adopting multi-modular scheme, i.e. the superheated steam flows produced by multiple SMR-based nuclear heating system (NSSS) modules are combined to drive a common thermal load, the strong safety feature of a SMR can be applied to large-scale nuclear plants. To improve the economic competitiveness, it is meaningful to integrate multiple NSSS modules by the scheme of feedwater distribution, i.e. sharing a common pump and distributing feedwater by adjusting the opening of regulating valve of each module. The module coordination control of multiple SMR-based NSSS modules coupled by feedwater distribution is essentially the flowrate-pressure control of the common secondary-loop fluid flow network (FFN). In this paper, the nonlinear differential-algebraic model for the FFNs with a single feedwater pump is first given. A novel distributed adaptive flowrate-pressure control is proposed, which is then applied to realize the module coordination. Numerical simulation results in the case of coordination control of two MHTGR-based NSSS modules integrated by feedwater distribution scheme show the feasibility as well as the satisfactory transient performance of this newly-built coordination control law.

  1. Machine Shop. Module 8: CNC (Computerized Numerical Control). Instructor's Guide.

    Science.gov (United States)

    Crosswhite, Dwight

    This document consists of materials for a five-unit course on the following topics: (1) safety guidelines; (2) coordinates and dimensions; (3) numerical control math; (4) programming for numerical control machines; and (5) setting and operating the numerical control machine. The instructor's guide begins with a list of competencies covered in the…

  2. Does Language Proficiency Modulate Oculomotor Control? Evidence from Hindi-English Bilinguals

    Science.gov (United States)

    Singh, Niharika; Mishra, Ramesh Kumar

    2012-01-01

    Though many previous studies have reported enhanced cognitive control in bilinguals, few have investigated if such control is modulated by language proficiency. Here, we examined the inhibitory control of high and low proficient Hindi-English bilinguals on an oculomotor Stroop task. Subjects were asked to make a saccade as fast as possible towards…

  3. Control of a Dual-Stator Flux-Modulated Motor for Electric Vehicles

    Directory of Open Access Journals (Sweden)

    Xinhua Guo

    2016-07-01

    Full Text Available This paper presents the control strategies for a novel dual-stator flux-modulated (DSFM motor for application in electric vehicles (EVs. The DSFM motor can be applied to EVs because of its simple winding structure, high reliability, and its use of two stators and rotating modulation steels in the air gap. Moreover, it outperforms conventional brushless doubly-fed machines in terms of control performance. Two stator-current-oriented vector controls with different excitation in the primary winding, direct and alternating current excitation, are designed, simulated, and evaluated on a custom-made DSFM prototype allowing the decoupled control of torque. The stable speed response and available current characteristics strongly validate the feasibility of the two control methods. Furthermore, the proposed control methods can be employed in other applications of flux-modulated motors.

  4. Widely Tunable Terahertz Phase Modulation with Gate-Controlled Graphene Metasurfaces

    Directory of Open Access Journals (Sweden)

    Ziqi Miao

    2015-11-01

    Full Text Available As the basis of a diverse set of photonic applications, such as hologram imaging, polarization, and wave front manipulation, the local phase control of electromagnetic waves is fundamental in photonic research. However, currently available bulky, passive, range-limited phase modulators pose an obstacle in photonic applications. Here, we propose a new mechanism to achieve a wide phase modulation range, with graphene used as a tunable loss to drive an underdamped to overdamped resonator transition. Based on this mechanism, we present widely tunable phase modulation in the terahertz regime, realized in gate-tuned ultrathin reflective graphene metasurfaces. A one-port resonator model, supported by full-wave simulations, explains the underlying physics of the discovered extreme phase modulation and indicates general strategies for designing tunable photonic devices. As an example, we demonstrate a gate-tunable terahertz (THz polarization modulator with a graphene metasurface. Our findings establish the possibility for photonic applications based on active phase manipulation.

  5. Modular microfluidic systems using reversibly attached PDMS fluid control modules

    DEFF Research Database (Denmark)

    Skafte-Pedersen, Peder; Sip, Christopher G.; Folch, Albert

    2013-01-01

    The use of soft lithography-based poly(dimethylsiloxane) (PDMS) valve systems is the dominating approach for high-density microscale fluidic control. Integrated systems enable complex flow control and large-scale integration, but lack modularity. In contrast, modular systems are attractive altern...

  6. STUDIES AND EXPERIMENTAL RESEARCH CONCERNING THE PERFORMANCES OF THE INTERNAL COMBUSTION ENGINE, CONTROLLED OVER THE POWERTRAIN CONTROL MODULE

    OpenAIRE

    Narcis URICANU; Emanuel RESIGA; Mihon, Liviu; Danila IORGA; Hiticas, Ioan

    2012-01-01

    the paper present how can be controlled a road vehicle through a powertrain control module, a type of ECU, programmable ECU (Electronic Control Unit), when we want to increase the performances of the engine, compared with the standard performances of the engine. The programmable ECU is a control system which replaces the ECU from the vehicle and is able to manage, better than the standard ECU, the behaviour of the spark ignition engine on increasing the performances. Sports cars need to obtai...

  7. Motor skill experience modulates executive control for task switching.

    Science.gov (United States)

    Yu, Qiuhua; Chan, Chetwyn C H; Chau, Bolton; Fu, Amy S N

    2017-10-01

    This study aimed to investigate the effect of types of motor skills, including open and closed skills on enhancing proactive and reactive controls for task switching. Thirty-six athletes in open (n=18) or closed (n=18) sports and a control group (n=18) completed the task-switching paradigm and the simple reaction task. The task-switching paradigm drew on the proactive and reactive control of executive functions, whereas the simple reaction task assessed the processing speed. Significant Validity×Group effect revealed that the participants with open skills had a lower switch cost of response time compared to the other two groups when the task cue was 100% valid; whereas the participants regardless of motor skills had a lower switch cost of response time compared to the control group when the task cue was 50% valid. Hierarchical stepwise regression analysis further confirmed these findings. For the simple reaction task, there were no differences found among the three groups. These findings suggest that experience in open skills has benefits of promoting both proactive and reactive controls for task switching, which corresponds to the activity context exposed by the participants. In contrast, experience in closed skills appears to only benefit development of reactive control for task switching. The neural mechanisms for the proactive and reactive controls of executive functions between experts with open and closed skills call for future study. Copyright © 2017. Published by Elsevier B.V.

  8. Electrically and spatially controllable PDLC phase gratings for diffraction and modulation of laser beams

    Energy Technology Data Exchange (ETDEWEB)

    Hadjichristov, Georgi B., E-mail: georgibh@issp.bas.bg [Laboratory of Optics and Spectroscopy, Georgi Nadjakov Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee Blvd., BG-1784 Sofia (Bulgaria); Marinov, Yordan G.; Petrov, Alexander G. [Laboratory of Biomolecular Layers, Georgi Nadjakov Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee Blvd., BG-1784 Sofia, Bulgaria (Bulgaria)

    2016-03-25

    We present a study on electrically- and spatially-controllable laser beam diffraction, electrooptic (EO) phase modulation, as well as amplitude-frequency EO modulation by single-layer microscale polymer-dispersed liquid crystal (PDLC) phase gratings (PDLC SLPGs) of interest for device applications. PDLC SLPGs were produced from nematic liquid crystal (LC) E7 in photo-curable NOA65 polymer. The wedge-formed PDLC SLPGs have a continuously variable thickness (2–25 µm). They contain LC droplets of diameters twice as the layer thickness, with a linear-gradient size distribution along the wedge. By applying alternating-current (AC) electric field, the PDLC SLPGs produce efficient: (i) diffraction splitting of transmitted laser beams; (ii) spatial redistribution of diffracted light intensity; (iii) optical phase modulation; (iv) amplitude-frequency modulation, all controllable by the driven AC field and the droplet size gradient.

  9. Multi-focus two-photon polymerization technique based on individually controlled phase modulation.

    Science.gov (United States)

    Obata, Kotaro; Koch, Jürgen; Hinze, Ulf; Chichkov, Boris N

    2010-08-02

    Multi-focus two-photon polymerization with a spatial light modulator is demonstrated. The spatial light modulator generates multi-focus spots via phase modulation technique controlled by a computer generated hologram (CGH) pattern. Each focus spot can be individually addressed in position and laser intensity. The multi-focus two-photon polymerization technique allows the fabrication of complex 2-D and 3-D structures both symmetric and asymmetric. Smooth sine curved polymerized lines with amplitude of 5 microm and a period of 200 microm were obtained by fast switching of the CGH patterns.

  10. Research of energy efficiency evaluation parameters for power quality control device based on IGBT module

    Science.gov (United States)

    Xu, Jieyan; Liu, Yang; Mao, Yongqiu; Chen, Zheng; Jia, Rongda; Zhao, Caiyi; Yang, Xi

    2017-01-01

    In this paper, the energy efficiency evaluation parameters for power quality control device based on IGBT modules have been discussed. First of all, energy consumption of the typical power quality control equipment, such as SVG, APF and MEC, under the rated conditions, have been analyzed to identify the main energy-consuming parts. Then, energy loss mechanism and energy saving path of IGBT module have been discussed. And the energy saving improvement direction of the power quality control equipment based on IGBT module is identified at the same time. At last, the applicable energy efficiency evaluation parameters for power quality control device have been selected, based on the research of the product performances for energy efficiency of power grid.

  11. Designing an Electro-Hydraulic Control Module for an Open-Circuit Variable Displacement Pump

    DEFF Research Database (Denmark)

    Pedersen, Henrik Clemmensen; Andersen, Torben Ole; Hansen, Michael Rygaard

    2005-01-01

    This paper deals with the problem of designing an electric control module for a Sauer-Danfoss Series 45 H-frame open circuit axial piston pump. The purpose of the electric control module is to replace the existing hydro-mechanical (LS) regulator, and enable the pump to follow a reference pressure...... consideration. Based on the initial topology experimental results are presented and a simulation comparison is made with the original hydro-mechanical controlled pump. Based on these results, improvements for a second prototype are presented along with a simulation result for this....

  12. Troubleshooting of an Electromechanical System (Westinghouse PLC Controlling a Pneumatic Robot). High-Technology Training Module.

    Science.gov (United States)

    Tucker, James D.

    This training module on the troubleshooting of an electromechanical system, The Westinghouse Programmable Logic Controller (PLC) controlling a pneumatic robot, is used for a troubleshooting unit in an electromechanical systems/robotics and automation systems course. In this unit, students locate and repair a defect in a PLC-operated machine. The…

  13. Cable tensioned membrane solar collector module with variable tension control

    Science.gov (United States)

    Murphy, Lawrence M.

    1985-01-01

    Disclosed is a solar collector comprising a membrane for concentrating sunlight, a plurality of elongated structural members for suspending the membrane member thereon, and a plurality of control members for adjustably tensioning the membrane member, as well as for controlling a focus produced by the membrane members. Each control member is disposed at a different corresponding one of the plurality of structural members. The collector also comprises an elongated flexible tensioning member, which serves to stretch the membrane member and to thereafter hold it in tension, and a plurality of sleeve members, which serve to provide the membrane member with a desired surface contour during tensioning of the membrane member. The tensioning member is coupled to the structural members such that the tensioning member is adjustably tensioned through the structural members. The tensioning member is also coupled to the membrane member through the sleeve members such that the sleeve members uniformly and symmetrically stretch the membrane member upon applying tension to the tensioning member with the control members.

  14. Experimental results of controlled PV module for building integrated PV systems

    Energy Technology Data Exchange (ETDEWEB)

    Roman, E.; Alonso, R.; Ibanez, P.; Elorduizapatarietxe, S. [Energy Unit, Robotiker Corporacion Tecnologica Tecnalia, Parque Tecnologico de Zamudio. Edif. 202, 48170 Zamudio (Spain); Martinez, V.; Jimeno, J.C. [EHU/UPV Instituto de Tecnologia Microelectronica, Alda. Urquijo s/n, 48013 Bilbao (Spain)

    2008-05-15

    Last issues about Building Integrated Photovoltaic Systems (BIPV) still show average Performance Ratio (PR) values in the range of 0.75-0.80. The main causes well known: partial shadows, temperature effects, PV inverter losses, thermal losses, etc. and mismatching losses. Ideally, all the modules work in the same conditions, but differences between modules really exist due to differences in the working temperature, the inclination or orientation angles, differences in the I-V characteristic coming from the manufacturing process, etc. The effect is that the output power of the complete PV system is lower than the addition of the power of each PV module. These mismatching losses can be decreased by means of suitable electronics. This paper presents the experimental results obtained over PV systems equipped with controlled PV modules, PV modules with low cost and high efficiency DC-DC converters, including MPPT algorithm and other functions, such as power control and Power Line Communications (PLC). Tests have been divided into two great categories: tests on the electronic performance of the DC-DC converter and tests on grid-connected PV systems with multiple DC-DC converters. Many of these tests have been carried out taking advantage of the PV System Test Platform, a powerful tool especially designed by Robotiker to evaluate all kind of PV systems, especially systems with differences between modules. Aspects of the DC-DC converter performance have been detailed and among the most important experiments, the paper analyses different situations such as partial shadows, different inclined planes, PV systems with different PV modules, and finally a comparison between a conventional system and a system composed by controlled PV modules have been described. To sum up, the importance of a good system dimensioning is analysed, with very interesting results. (author)

  15. Wavelength-tunable and pulse-width variable Fourier domain mode-locking lasers.

    Science.gov (United States)

    Lee, Eung Je; Kim, Yong Pyung

    2011-12-15

    In this study, wavelength-tunable and pulse-width variable Fourier domain mode-locking lasers were developed with a repetition rate of 60.9 kHz. A spectral laser tuning range of over 100 nm was achieved by tuning the offset voltage to a fiber Fabry-Perot tunable filter (FFP-TF). The pulse width variation was achieved with amplitude modulation of the driving voltage to the FFP-TF. The pulse width ranged from 6.2 μs to 55 ns. The linewidth of the laser changed, from 0.109 to 0.083 nm, according to the pulse width variation.

  16. MATLAB Stability and Control Toolbox Trim and Static Stability Module

    Science.gov (United States)

    Kenny, Sean P.; Crespo, Luis

    2012-01-01

    MATLAB Stability and Control Toolbox (MASCOT) utilizes geometric, aerodynamic, and inertial inputs to calculate air vehicle stability in a variety of critical flight conditions. The code is based on fundamental, non-linear equations of motion and is able to translate results into a qualitative, graphical scale useful to the non-expert. MASCOT was created to provide the conceptual aircraft designer accurate predictions of air vehicle stability and control characteristics. The code takes as input mass property data in the form of an inertia tensor, aerodynamic loading data, and propulsion (i.e. thrust) loading data. Using fundamental nonlinear equations of motion, MASCOT then calculates vehicle trim and static stability data for the desired flight condition(s). Available flight conditions include six horizontal and six landing rotation conditions with varying options for engine out, crosswind, and sideslip, plus three take-off rotation conditions. Results are displayed through a unique graphical interface developed to provide the non-stability and control expert conceptual design engineer a qualitative scale indicating whether the vehicle has acceptable, marginal, or unacceptable static stability characteristics. If desired, the user can also examine the detailed, quantitative results.

  17. Mathematical analysis and coordinated current allocation control in battery power module systems

    Science.gov (United States)

    Han, Weiji; Zhang, Liang

    2017-12-01

    As the major energy storage device and power supply source in numerous energy applications, such as solar panels, wind plants, and electric vehicles, battery systems often face the issue of charge imbalance among battery cells/modules, which can accelerate battery degradation, cause more energy loss, and even incur fire hazard. To tackle this issue, various circuit designs have been developed to enable charge equalization among battery cells/modules. Recently, the battery power module (BPM) design has emerged to be one of the promising solutions for its capability of independent control of individual battery cells/modules. In this paper, we propose a new current allocation method based on charging/discharging space (CDS) for performance control in BPM systems. Based on the proposed method, the properties of CDS-based current allocation with constant parameters are analyzed. Then, real-time external total power requirement is taken into account and an algorithm is developed for coordinated system performance control. By choosing appropriate control parameters, the desired system performance can be achieved by coordinating the module charge balance and total power efficiency. Besides, the proposed algorithm has complete analytical solutions, and thus is very computationally efficient. Finally, the efficacy of the proposed algorithm is demonstrated using simulations.

  18. Analysis of amplitude modulated control features for ECoG neuroprosthetics.

    Science.gov (United States)

    Sanchez, Justin C; Carney, Paul R; Principe, Jose C

    2006-01-01

    Electrocorticogram recordings for neuroprosthetics provide an intermediate level of abstraction between EEG and microwire single neuron recordings. For adaptive filtering methodologies used in neuroprosthetics, extraction of spatio-control parameters remains a difficulty. Since amplitude modulation in extracellular recordings plays a key role in both neuronal activation and rate coding, seeking spatial pattern classification and temporally intermittent population synchronization in terms of increased voltage may provide viable control signals. This study seeks to explore preprocessing modalities that emphasize amplitude modulation in the ECoG above the level of noise and background fluctuations in order to derive the commands for complex control tasks. The decoding performance of the amplitude modulation across the recording spectra was found to be spatially specific in the cortex.

  19. DEVELOPING A LEARNING MODULE OF COMPUTER NUMERICALLY CONTROL GSK 983 MACHINES TO ENHANCE STUDENTS’ LEARNING OUTCOMES

    Directory of Open Access Journals (Sweden)

    Martono Martono

    2016-09-01

    Full Text Available This study aims at: (1 producing a learning module of Computer Numerically Control (CNC GSK 983 machines to enhance the students’ learning outcomes, (2 investigating the learning process of CNC GSK 983 machines in vocational schools, (3 analyzing the effectiveness of the developed module in vocational schools. This study refers to the research procedure of design and development by Richey and Klein consisting of (1 observations of learning and products development, (2 internal and external validation, and (3 testing the effectiveness of the product in the field. The data was analyzed using T-Test. The results showed that: (1 the CNC learning outcomes in Vocational Schools did not meet the expectation; (2 learning modules of CNC GSK 983 to enhance the students’ learning outcomes was developed, and (3 the developed module was effective to enhance the students’ learning outcomes. The results of the t-test showed that there was a significant difference between the learning outcomes with the module and the learning outcomes without the module. It means that the module can improve the students’ learning outcomes.

  20. RCT: Module 2.08, Radiological Source Control, Course 8774

    Energy Technology Data Exchange (ETDEWEB)

    Hillmer, Kurt T. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-08-10

    radioactive source is material used for its emitted radiation. Sources are sealed or unsealed and are classified as accountable or exempt. Radioactive sources are used for response checks, functional checks, and the calibration of instruments and monitors to traceable standards. To ensure the safety and welfare of all personnel, it is important to maintain control of radioactive sources to minimize the potential for the spread of contamination, unnecessary exposure to personnel, loss or theft, and improper disposal. This course will prepare the student with the skills necessary for RCT qualification by passing quizzes, tests, and the RCT Comprehensive Phase 1, Unit 2 Examination (TEST 27566) and will provide in-the-field skills.

  1. White light wavefront control with a spatial light modulator

    CSIR Research Space (South Africa)

    Spangenberg, D-M

    2014-01-01

    Full Text Available , 335–342 (2011). 3. D. Grier, “A revolution in optical manipulation,” Nature 424, 810–816 (2003). 4. A. Jesacher, C. Maurer, A. Schwaighofer, S. Bernet and M. Ritsch-Marte, “Full phase and amplitude control of holographic optical tweezers with high... by the use of a phase checkerboard pattern in computer generated holograms,” Appl. Opt. 47(4), 602 (2008). 10. S. Furhapter, A. Jesacher, S. Bernet and M. Ritsch-Marte,“Spiral phase contrast imaging in microscopy,” Opt. Express 13, 689–694 (2005). 11. T...

  2. Deficient cytokine control modulates temporomandibular joint pain in rheumatoid arthritis.

    Science.gov (United States)

    Ahmed, Neveen; Catrina, Anca I; Alyamani, Ahmed O; Mustafa, Hamid; Alstergren, Per

    2015-08-01

    The aim was to investigate how endogenous cytokine control of tumor necrosis factor (TNF) influences temporomandibular joint (TMJ) pain in relation to the role of anti-citrullinated peptide antibodies (ACPA) in patients with rheumatoid arthritis (RA). Twenty-six consecutive patients with TMJ RA were included. Temporomandibular joint pain intensity was assessed at rest, on maximum mouth opening, on chewing, and on palpation. Mandibular movement capacity and degree of anterior open bite (a clinical sign of structural destruction of TMJ tissues) were also assessed. Systemic inflammatory activity was assessed using the Disease Activity Score in 28 joints (DAS28) for rheumatoid arthritis. Samples of TMJ synovial fluid and blood were obtained and analyzed for TNF, its soluble receptor, soluble TNF receptor II (TNFsRII), and ACPA. A high concentration of TNF in relation to the concentration of TNFsRII in TMJ synovial fluid was associated with TMJ pain on posterior palpation on maximum mouth opening. The ACPA concentration correlated significantly to the TNF concentration, but not to the TNFsRII concentration, indicating that increased inflammatory activity is mainly caused by an insufficient increase in anti-inflammatory mediators. This study indicates that TMJ pain on palpation in patients with RA is related to a deficiency in local cytokine control that contributes to increased inflammatory activity, including sensitization to mechanical stimuli over the TMJ. © 2015 Eur J Oral Sci.

  3. Application of Space Vector Modulation in Direct Torque Control of PMSM

    Directory of Open Access Journals (Sweden)

    Michal Malek

    2008-01-01

    Full Text Available The paper deals with an improvement of direct torque control method for permanent magnet synchronous motor drives. Electrical torque distortion of the machine under original direct torque control is relatively high and if proper measures are taken it can be substantially decreased. The proposed solution here is to combine direct torque control with the space vector modulation technique. Such approach can eliminate torque distortion while preserving the simplicity of the original method.

  4. Chalcogenide nanocrystal assembly: Controlling heterogeneity and modulating heterointerfaces

    Science.gov (United States)

    Davis, Jessica

    chalcogenide NC gels with different NC components with control over the degree of mixing. In order to control the degree of mixing, the factors that underscore sol-gel oxidative assembly were elucidated and the aggregation and gelation kinetics of metal chalcogenide QDs were monitored through time-resolved dynamic light scattering (TR-DLS), and nuclear magnetic resonance spectroscopy (NMR). Through these kinetic studies of the surface speciation of metal chalcogenides, control over heterogeneity in dual component CdSe-ZnS system, was achieved through adjustment of the capping ligand, the native crystal structure and the chalcogenide, thereby changing the relative rates of assembly for each component independently.

  5. Stiffness determination of the controlled wheel module of a two-axle vehicle

    Directory of Open Access Journals (Sweden)

    Belevtseva N.V.

    2016-08-01

    Full Text Available The conditions of a secure loss of stability of a two-axle wheel vehicle with absolutely hard steering have been found before. The analytically derived conditions of a secure stability loss in case of torsional stiffness are dependent on the relationship between the slipping resistance coefficients, the transverse clutch coefficients on the axes, and the torsional stiffness of the controlled wheel module. In this case, the trail distance is taken into account in the wheel module control system, the mass of the module being neglected. The approach suggested in the paper does take into account the mass of the controlled wheel module. The slipping forces are presented accurate to a cubic term of expansion in slipping angles. The torsional stiffness intervals have been found that provide a secure loss of stability of a two-axle wheel vehicle model. The intervals have been obtained on the basis of a bifurcation analysis of actual bifurcations of the stationary states in the vicinity of the rectilinear motion of the model. Diagrams that illustrate the fulfillment of secure stability loss conditions and allow using the results obtained in designing a wheel module are presented in the paper. The technique used is alternative to the well-known M. Bautin’s approach to determination of secure-insecure conditions in case of a divergent loss of stability.

  6. A DC-Link Modulation Scheme with Phase-Shifted Current Control for Harmonic Cancellations in Multidrive Applications

    DEFF Research Database (Denmark)

    Yang, Yongheng; Davari, Pooya; Zare, Firuz

    2016-01-01

    of a new DC link modulation scheme with a phase-shifted current control enabled by the SCR. The DC-link current modulation scheme is implemented by adding and subtracting specific modulation levels, which makes the total currents drawn from the grid “multi-level”, resulting in an improved current quality...

  7. O-Fucose Modulates Notch-Controlled Blood Lineage Commitment

    Science.gov (United States)

    Yan, Quanjian; Yao, David; Wei, Lebing L.; Huang, Yuanshuai; Myers, Jay; Zhang, Lihua; Xin, Wei; Shim, Jeongsup; Man, Yunfang; Petryniak, Bronislawa; Gerson, Stanton; Lowe, John B.; Zhou, Lan

    2010-01-01

    Notch receptors are cell surface molecules essential for cell fate determination. Notch signaling is subject to tight regulation at multiple levels, including the posttranslational modification of Notch receptors by O-linked fucosylation, a reaction that is catalyzed by protein O-fucosyltransferase-1 (Pofut1). Our previous studies identified a myeloproliferative phenotype in mice conditionally deficient in cellular fucosylation that is attributable to a loss of Notch-dependent suppression of myelopoiesis. Here, we report that hematopoietic stem cells deficient in cellular fucosylation display decreased frequency and defective repopulating ability as well as decreased lymphoid but increased myeloid developmental potential. This phenotype may be attributed to suppressed Notch ligand binding and reduced downstream signaling of Notch activity in hematopoietic stem cells. Consistent with this finding, we further demonstrate that mouse embryonic stem cells deficient in Notch1 (Notch1−/−) or Pofut1 (Pofut1−/−) fail to generate T lymphocytes but differentiate into myeloid cells while coculturing with Notch ligand–expressing bone marrow stromal cells in vitro. Moreover, in vivo hematopoietic reconstitution of CD34+ progenitor cells derived from either Notch1−/− or Pofut1−/− embryonic stem cells show enhanced granulopoiesis with depressed lymphoid lineage development. Together, these results indicate that Notch signaling maintains hematopoietic lineage homeostasis by promoting lymphoid development and suppressing overt myelopoiesis, in part through processes controlled by O-linked fucosylation of Notch receptors. PMID:20363915

  8. Development and implementation of quality control strategies for CMS silicon strip tracker modules

    CERN Document Server

    Dirkes, Guido

    The LHC will explore physics at the energy frontier and will address many open questions in particle physics, like the search for the Higgs boson or Supersymmetry. For both high resolution track and vertex reconstruction is vital. The CMS silicon tracker consists of 15232 detector modules. Production and assembly of these will span two and a half years period, during which the quality control chain has to ensure functionality and reliability of the modules produced. The CMS group in Karlsruhe will produce and qualify 1600 modules. Therefore automatic test systems are developed and test strategies are worked out. Already during the RnD phase, first prototype tests were performed and some weak points of the design were uncovered. Two test stations are built. One focuses on a fast functionality test, including an active thermal cycle. The other focuses on debugging and repair requirements, including additional test options with lasers, radioactive sources, probes and infrared LEDs. For quality control measuremen...

  9. Spectrum-modulating fiber-optic sensors for aircraft control systems

    Science.gov (United States)

    Beheim, Glenn; Fritsch, Klaus

    1987-01-01

    A family of fiber-optic sensors for aircraft engine control systems is described. Each of these sensors uses a spectrum-modulation method to obtain an output which is largely independent of the fiber link transmissivity. A position encoder is described which uses a code plate to digitally modulate the sensor output spectrum. Also described are pressure and temperature sensors, each of which uses a Fabry-Perot cavity to modulate the sensor output spectrum as a continuous function of the measurand. A technique is described whereby a collection of these sensors may be effectively combined to perform a number of the measurements which are required by an aircraft-engine control system.

  10. Resonance width distribution for open quantum systems

    OpenAIRE

    Shchedrin, Gavriil; Zelevinsky, Vladimir

    2011-01-01

    Recent measurements of resonance widths for low-energy neutron scattering off heavy nuclei show large deviations from the standard Porter-Thomas distribution. We propose a new resonance width distribution based on the random matrix theory for an open quantum system. Two methods of derivation lead to a single analytical expression; in the limit of vanishing continuum coupling, we recover the Porter-Thomas distribution. The result depends on the ratio of typical widths $\\Gamma$ to the energy le...

  11. RPC communication layer and introduction to data protection for embedded PC based control and data acquisition module

    Science.gov (United States)

    Kwiatkowski, Maciej; Roszkowski, Piotr; Zabolotny, Wojciech M.; Pozniak, Krzysztof; Romaniuk, Ryszard

    2005-09-01

    This paper describes an implementation of the communication layer based on remote procedure calling ONC RPC and presents the first prototype of hardware data protection module for control and data acquisition module being developed by the ELHEP Group for the DESY research center in Hamburg. This control and DAQ module is designed for the SIMCON module (SIMulator and CONtroller) aimed to steer the nine-cell super conducting niobium resonators built and produced for TESLA and X-FEL projects. Solutions described here will allow to establish safe connections from any place in the world and control physics experiments via Internet network.

  12. Optimal feedback control successfully explains changes in neural modulations during experiments with brain-machine interfaces

    Directory of Open Access Journals (Sweden)

    Miriam eZacksenhouse

    2015-05-01

    Full Text Available Recent experiments with brain-machine-interfaces (BMIs indicate that the extent of neural modulations increased abruptly upon starting to operate the interface, and especially after the monkey stopped moving its hand. In contrast, neural modulations that are correlated with the kinematics of the movement remained relatively unchanged. Here we demonstrate that similar changes are produced by simulated neurons that encode the relevant signals generated by an optimal feedback controller during simulated BMI experiments. The optimal feedback controller relies on state estimation that integrates both visual and proprioceptive feedback with prior estimations from an internal model. The processing required for optimal state estimation and control were conducted in the state-space, and neural recording was simulated by modeling two populations of neurons that encode either only the estimated state or also the control signal. Spike counts were generated as realizations of doubly stochastic Poisson processes with linear tuning curves. The model successfully reconstructs the main features of the kinematics and neural activity during regular reaching movements. Most importantly, the activity of the simulated neurons successfully reproduces the observed changes in neural modulations upon switching to brain control. Further theoretical analysis and simulations indicate that increasing the process noise during normal reaching movement results in similar changes in neural modulations. Thus we conclude that the observed changes in neural modulations during BMI experiments can be attributed to increasing process noise associated with the imperfect BMI filter, and, more directly, to the resulting increase in the variance of the encoded signals associated with state estimation and the required control signal.

  13. 75 FR 69681 - Proposed Collection; Comment Request; California Health Interview Survey Cancer Control Module...

    Science.gov (United States)

    2010-11-15

    ..., diet, physical activity, obesity, and human papillomavirus. Additionally, CHIS is designed to be...] [FR Doc No: 2010-28648] DEPARTMENT OF HEALTH AND HUMAN SERVICES National Institutes of Health Proposed Collection; Comment Request; California Health Interview Survey Cancer Control Module (CHIS-CCM) 2011 (NCI...

  14. Cyclic pitch for the control of wind turbine noise amplitude modulation

    DEFF Research Database (Denmark)

    Bertagnolio, Franck; Aagaard Madsen, Helge; Fischer, Andreas

    2014-01-01

    Using experimental data acquired during a wind turbine measurement campaign, it is shown that amplitude modulation of aerodynamic noise can be generated by the rotating blades in conjunction with the atmospheric wind shear. As an attempt to alleviate this phenomenon, a control strategy is designed...

  15. How Positive Affect Modulates Cognitive Control: The Costs and Benefits of Reduced Maintenance Capability

    Science.gov (United States)

    Dreisbach, Gesine

    2006-01-01

    Adaptive action in a constantly changing environment requires the ability to maintain intentions and goals over time and to flexibly switch between these goals in response to significant changes. Dreisbach and Goschke (2004) argued that positive affect modulates these antagonistic control demands in favor of a more flexible but also more…

  16. Digital control of laser modes with an intra-cavity spatial light modulator

    CSIR Research Space (South Africa)

    Ngcobo, S

    2014-02-01

    Full Text Available In this paper we outline a simple laser cavity which produces customised on-demand digitally controlled laser modes by replacing the end-mirror of the cavity with an electrically addressed reflective phase-only spatial light modulator as a digital...

  17. Automated vision-based quality control for electro-optical module manufacturing

    Science.gov (United States)

    Dar, Iqbal M.

    1997-09-01

    The paper describes an inspection system architecture for electro-optical module inspection. The manufacturing of electro-optical modules involves assembly of electronic component and optical component mounts on a printed circuit board. The system consists of a controls layer and a machine vision layer. The controls layer manages seven axis positioning system. The machine vision layer performs automated inspection of the module at component level as well as at joint level. There are three operation modes of the system. Use-friendly graphic interfaces have been developed for system operation. The system can be programmed off-line for positioning information. Once the coordinates for various inspection locations are programmed the system automatically learns fuzzy classification prototypes. The prototypes are then utilized for module inspection. A module scanning algorithm has been developed that can detect and identify electronics or optical missing components. Fuzzy average square weighted Euclidean distance classifier has been used for missing component classification. Results are reported to demonstrate the missing component algorithm.

  18. First Metatarsal Head and Medial Eminence Widths with and Without Hallux Valgus.

    Science.gov (United States)

    Lenz, Robin C; Nagesh, Darshan; Park, Hannah K; Grady, John

    2016-09-02

    Resection of the medial eminence in hallux valgus surgery is common. True hypertrophy of the medial eminence in hallux valgus is debated. No studies have compared metatarsal head width in patients with hallux valgus and control patients. We reviewed 43 radiographs with hallux valgus and 27 without hallux valgus. We measured medial eminence width, first metatarsal head width, and first metatarsal shaft width in patients with and without radiographic hallux valgus. Medial eminence width was 1.12 mm larger in patients with hallux valgus (P hallux valgus (P hallux valgus. However, frontal plane rotation of the first metatarsal likely accounts for this difference.

  19. A direct torque control scheme for permanent magnet synchronous motors based on space vector modulation

    Science.gov (United States)

    Su, Xiao-hui; Xu, Shu-Ping

    2013-03-01

    In order to solve the problem of direct torque control (DTC) for permanent magnet synchronous motor (PMSM) related to the flux and the torque ripple and the uncertainty of switching frequency, A novel direct torque control system based on space vector modulation(SVM-DTC) for permanent magnet synchronous motor was proposed. In this method flux and torque are controlled through stator voltage components in stator flux linkage coordinate axes and space vector modulation is used to control inverters. Therefore, the errors of torque and flux linkage could be compensated accurately. The whole system has only one easily adjustable PI adjuster and needs no high for hardware and easy for realize. The simulation results verify the feasibility of this method, reduction of the flux and the torque ripple, and the good performance of DTC.

  20. Using the local positioning system based on Pulse Width Modulation ...

    African Journals Online (AJOL)

    Michael Horsfall

    location using a GPS which calculates longitude and latitude of the object by the data received by the satellites ... In multi-path environments, in which we have radio wave reflectors, a weight s(r) will be dedicated to each vector (r) of the workspace. Then, position (Rx) can ..... Figure8: the robot trajectory in a circular path.

  1. A DSP-based discrete space vector modulation direct torque control of sensorless induction machines

    Energy Technology Data Exchange (ETDEWEB)

    Khoucha, F.; Marouani, K.; Kheloui, A.; Aliouane, K.

    2004-07-01

    In this paper, we present a Direct Torque Control scheme of an induction motor operating without speed sensor. The estimation of the stator flux and the rotor speed is performed by an adaptive observer. In order to reduce the torque, flux, current and speed ripple a Discrete Space Vector Modulation (DSVM-DTC) strategy is implemented using a DSP-based hardware. To illustrate the performances of this control scheme, experimental results are presented. (author)

  2. Impact on learning of an e-learning module on leukaemia: a randomised controlled trial

    Science.gov (United States)

    2012-01-01

    Background e-learning resources may be beneficial for complex or conceptually difficult topics. Leukaemia is one such topic, yet there are no reports on the efficacy of e-learning for leukaemia. This study compared the learning impact on senior medical students of a purpose-built e-learning module on leukaemia, compared with existing online resources. Methods A randomised controlled trial was performed utilising volunteer senior medical students. Participants were randomly allocated to Study and Control groups. Following a pre-test on leukaemia administered to both groups, the Study group was provided with access to the new e-learning module, while the Control group was directed to existing online resources. A post-test and an evaluation questionnaire were administered to both groups at the end of the trial period. Results Study and Control groups were equivalent in gender distribution, mean academic ability, pre-test performance and time studying leukaemia during the trial. The Study group performed significantly better than the Control group in the post-test, in which the group to which the students had been allocated was the only significant predictor of performance. The Study group’s evaluation of the module was overwhelmingly positive. Conclusions A targeted e-learning module on leukaemia had a significant effect on learning in this cohort, compared with existing online resources. We believe that the interactivity, dialogic feedback and integration with the curriculum offered by the e-learning module contributed to its impact. This has implications for e-learning design in medicine and other disciplines. PMID:22640463

  3. Design development of the Apollo command and service module thrust vector attitude control systems

    Science.gov (United States)

    Peters, W. H.

    1978-01-01

    Development of the Apollo thrust vector control digital autopilot (TVC DAP) was summarized. This is the control system that provided pitch and yaw attitude control during velocity change maneuvers using the main rocket engine on the Apollo service module. A list of ten primary functional requirements for this control system are presented, each being subordinate to a more general requirement appearing earlier on the list. Development process functions were then identified and the essential information flow paths were explored. This provided some visibility into the particular NASA/contractor interface, as well as relationships between the many individual activities.

  4. Constant Width Planar Computation Characterizes ACC0

    DEFF Research Database (Denmark)

    Hansen, K.A.

    2004-01-01

    We obtain a characterization of ACC 0 in terms of a natural class of constant width circuits, namely in terms of constant width polynomial size planar circuits. This is shown via a characterization of the class of acyclic digraphs which can be embedded on a cylinder surface in such a way that all...

  5. Comparison of Arch Width Changes Following Orthodontic ...

    African Journals Online (AJOL)

    2015-11-21

    Nov 21, 2015 ... Materials and Methods: The study was conducted with pre- and post-treatment digital models from 240 patients. ... this distance was maintained in calculating posttreatment measurements (T2). Mandibular and maxillary arch ... Arch width changes after different treatment modalities or posterior arch width ...

  6. Automatic bias control system of high speed electro-optic modulator in DPSK Systems

    Science.gov (United States)

    Xu, Miao; Tong, Shoufeng; Wang, Dashuai

    2015-04-01

    In DPSK communication system, the traditional way for bias voltage is loading a fixed bias voltage on the electro-optic modulator. For the influence of the temperature changes, the half-wave voltage of the electro-optic modulator may change and the DC bias supply voltage will have a certain degree of random fluctuations at the meantime which will cause the DC bias point of the modulator drift and consequently the communication systems are affected. To enhance the stability of the DPSK optical communication system and control the bias of Mach-Zehnder electro-optic modulators automatically, a PID control method has been proposed in this paper. After the actual operation, a DPSK signal transmission with transfer rate of 5Gb/s is built. Using the complex spectrum analyzer, stable signal and the constellation can be received. The automatic control system basically meets the needs of the DPSK transmission system of high stability, high accuracy and capacity of resisting disturbance.

  7. Chirp-free direct modulation of 550 nm emission in Er3+ -Doped Fluoroindate glass by nonlinear feedback control

    Science.gov (United States)

    Cai, Runyu; Thitsa, Makhin; Bluiett, Althea; Brown, Ei; Hommerich, Uwe

    2017-06-01

    We propose a direct modulation method with nonlinear feedback controller which can produce chirp-free modulation of the output pulse without bulky external modulators. This work reports the design of the controller which, via a feedback loop, varies and controls the pump rate in real time by automatically adjusting the pump power to precisely modulate the emission of 550 nm in Er3+ -doped Fluoroindate glass under 1.48 μm pumping. In this interdisciplinary paper, well established theoretical tools from nonlinear control theory are applied to the dynamical system of the laser material in order to produce the desired output of the laser. The controller is simulated in MATLAB Simulink and the simulation results show that our technique yields precise modulation of the output intensity without frequency chirping. Results on both theoretical analysis of the control methodology and simulation are presented.

  8. Resonance width distribution for open quantum systems

    Science.gov (United States)

    Shchedrin, Gavriil; Zelevinsky, Vladimir

    2012-10-01

    Recent measurements of resonance widths for low-energy neutron scattering off heavy nuclei show large deviations from the Porter-Thomas distribution. We propose a “standard” width distribution based on the random matrix theory for a chaotic quantum system with a single open decay channel. Two methods of derivation lead to a single analytical expression that recovers, in the limit of very weak continuum coupling, the Porter-Thomas distribution. The parameter defining the result is the ratio of typical widths Γ to the energy level spacing D. Compared to the Porter-Thomas distribution, the new distribution suppresses small widths and increases the probabilities of larger widths. We show also that it is necessary to take into account the γ channels.

  9. ADAR1-Mediated RNA Editing, A Novel Mechanism Controlling Phenotypic Modulation of Vascular Smooth Muscle Cells.

    Science.gov (United States)

    Fei, Jia; Cui, Xiao-Bing; Wang, Jia-Ning; Dong, Kun; Chen, Shi-You

    2016-07-22

    Vascular smooth muscle cell (SMC) phenotypic modulation is characterized by the downregulation of SMC contractile genes. Platelet-derived growth factor-BB, a well-known stimulator of SMC phenotypic modulation, downregulates SMC genes via posttranscriptional regulation. The underlying mechanisms, however, remain largely unknown. To establish RNA editing as a novel mechanism controlling SMC phenotypic modulation. Precursor mRNAs (pre-mRNA) of SMC myosin heavy chain and smooth muscle α-actin were accumulated while their mature mRNAs were downregulated during SMC phenotypic modulation, suggesting an abnormal splicing of the pre-mRNAs. The abnormal splicing resulted from SMC marker pre-mRNA editing that was facilitated by adenosine deaminase acting on RNA 1 (ADAR1), an enzyme converting adenosines to inosines (A→I editing) in RNA sequences. ADAR1 expression inversely correlated with SMC myosin heavy chain and smooth muscle α-actin levels; knockdown of ADAR1 restored SMC myosin heavy chain and smooth muscle α-actin expression in phenotypically modulated SMC, and editase domain mutation diminished the ADAR1-mediated abnormal splicing of SMC marker pre-mRNAs. Moreover, the abnormal splicing/editing of SMC myosin heavy chain and smooth muscle α-actin pre-mRNAs occurred during injury-induced vascular remodeling. Importantly, heterozygous knockout of ADAR1 dramatically inhibited injury-induced neointima formation and restored SMC marker expression, demonstrating a critical role of ADAR1 in SMC phenotypic modulation and vascular remodeling in vivo. Our results unraveled a novel molecular mechanism, that is, pre-mRNA editing, governing SMC phenotypic modulation. © 2016 American Heart Association, Inc.

  10. Training-test module in the system of pedagogical control of physical fitness in lower grades

    Directory of Open Access Journals (Sweden)

    I.N. Peleshenko

    2014-06-01

    Full Text Available Purpose : to substantiate model characteristics of physical fitness of elementary school students of secondary schools through the introduction of training and test module in the pedagogical control. Material : the study involved 320 boys and 278 girls in grades 1-4 schools in Kharkov number number 57, 112, 166. Results : the level of physical fitness of elementary school students with available motor tests and the results are compared between the experimental data and control classes. Found that the introduction of educational test module in the process of physical education in the experimental classes has enhanced the level of physical fitness. In the experimental classes compared to the control classes, there was an increase of indicators (boys 22.2%, girls 24.6%. Conclusions : the introduction of educational test module in the pedagogical control for primary school pupils, will improve the physical fitness of children in the experimental classes, compared with controls, as well as to determine the averages on basic motor tests that can be used as a model characteristics of physical fitness.

  11. Trait self-control is predicted by how reward associations modulate Stroop interference.

    Science.gov (United States)

    Wolff, Max; Krönke, Klaus-Martin; Goschke, Thomas

    2016-11-01

    Although cognitive control is commonly identified as the basis of self-controlled behavior, correlations found between trait self-control and laboratory measures of cognitive control such as Stroop interference are typically low. Based on the notion that self-control requires the ability to refrain from rewarded behaviors, and inspired by the recent finding that Stroop interference is modulated by reward associations, we propose the idea that the modulation of interference by reward associations (MIRA) is a cognitive marker of trait self-control. Two independent samples of participants completed (1) a modified Stroop task designed to assess MIRA and (2) two common measures of trait self-control: the Brief Self-Control Scale (BSCS) and the Barratt Impulsiveness Scale (BIS-11). MIRA was strongly correlated with the BSCS and moderately correlated with two of the three subscales of the BIS-11. MIRA thus appears to reflect a cognitive endophenotype of individual differences in self-control, and perhaps of related mental disorders.

  12. Periodic modulations controlling Kuznetsov–Ma soliton formation in nonlinear Schrödinger equations

    Energy Technology Data Exchange (ETDEWEB)

    Tiofack, C.G.L., E-mail: glatchio@yahoo.fr [Univ. Lille, CNRS, UMR 8523 – PhLAM – Physique des Lasers Atomes et Molécules, F-59000 Lille (France); Coulibaly, S.; Taki, M. [Univ. Lille, CNRS, UMR 8523 – PhLAM – Physique des Lasers Atomes et Molécules, F-59000 Lille (France); De Bièvre, S.; Dujardin, G. [Univ. Lille, CNRS, UMR 8524 – Laboratoire Paul Painlevé, F-59000 Lille (France); Équipe-Projet Mephysto, INRIA Lille-Nord Europe (France)

    2017-06-28

    We analyze the exact Kuznetsov–Ma soliton solution of the one-dimensional nonlinear Schrödinger equation in the presence of periodic modulations satisfying an integrability condition. We show that, in contrast to the case without modulation, the Kuznetsov–Ma soliton develops multiple compression points whose number, shape and position are controlled both by the intensity of the modulation and by its frequency. In addition, when this modulation frequency is a rational multiple of the natural frequency of the Kuznetsov–Ma soliton, a scenario similar to a nonlinear resonance is obtained: in this case the spatial oscillations of the Kuznetsov–Ma soliton's intensity are periodic. When the ratio of the two frequencies is irrational, the soliton's intensity is a quasiperiodic function. A striking and important result of our analysis is the possibility to suppress any component of the output spectrum of the Kuznetsov–Ma soliton by a judicious choice of the amplitude and frequency of the modulation. - Highlights: • Exact Kuznetsov–Ma soliton solution in presence of periodic coefficients is obtained. • The multiple compression points of the solution are studied. • The quasi-periodicity of the solution is discussed. • The possibility to suppress any component of the spectrum is analyzed.

  13. Width adjustment: relative dominance in unstable alluvial streams

    Science.gov (United States)

    Simon, Andrew

    1994-01-01

    The mechanisms that control the relative dominance of width adjustment in unstable streams are described. Specifically, the role of the following factors affecting the fluvial environment were investigated: vertical processes and fluvial action, bed-material particle, cohesive strength of bank material, and riparian vegetation.

  14. Characteristics of pulse width for an enhanced second harmonic generation

    Science.gov (United States)

    Zhang, Yun; Hyodo, Masaharu; Okada-Shudo, Yoshiko; Zhu, Yun; Wang, Xiaoyang; Zhu, Yong; Wang, Guiling; Chen, Chuangtian; Watanabe, Shuntaro; Watanabe, Masayoshi

    2017-03-01

    Temporal characteristics of a cavity enhancement second harmonic (SH) generation for picosecond laser pulse are investigated. We experimentally measured pulse width changes that were indued by group velocity mismatching (GVM), SH process, and enhancement cavity. It indicates that the generated pulse width is a combined effect of the GVM and SH process. Meanwhile, the effect of the enhancement cavity can be avoided by controlling its free spectrum range. A interferometric autocorrelator with a KBBF-PCD as nonlinear crystal is also composed and this extends the measurement light wavelength below 410 nm.

  15. The effects of lane width, shoulder width, and road cross-sectional reallocation on drivers' behavioral adaptations.

    Science.gov (United States)

    Mecheri, Sami; Rosey, Florence; Lobjois, Régis

    2017-07-01

    Previous research has shown that lane-width reduction makes drivers operate vehicles closer to the center of the road whereas hard-shoulder widening induces a position farther away from the road's center. The goal of the present driving-simulator study was twofold. First, it was aimed at further investigating the respective effects of lane and shoulder width on in-lane positioning strategies, by examining vehicle distance from the center of the lane. The second aim was to assess the impact on safety of three possible cross-sectional reallocations of the width of the road (i.e., three lane-width reductions with concomitant shoulder widening at a fixed cross-sectional width) as compared to a control road. The results confirmed that lane-width reduction made participants drive closer to the road's center. However, in-lane position was affected differently by lane narrowing, depending on the traffic situation. In the absence of oncoming traffic, lane narrowing gave rise to significant shifts in the car's distance from the lane's center toward the edge line, whereas this distance remained similar across lane widths during traffic periods. When the shoulders were at least 0.50m wide, participants drove farther away from both the road center and the lane center. Road reallocation operations resulted in vehicles positioned farther away from the edge of the road and less swerving behavior, without generating higher driving speeds. Finally, it is argued that road-space reallocation may serve as a good low-cost tool for providing a recovery area for steering errors, without impairing drivers' behavior. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Joint space width in dysplasia of the hip

    DEFF Research Database (Denmark)

    Jacobsen, Steffen; Sonne-Holm, Stig; Søballe, K

    2005-01-01

    . Neither subjects with dysplasia nor controls had radiological signs of ongoing degenerative disease at admission. The primary radiological discriminator of degeneration of the hip was a change in the minimum joint space width over time. There were no significant differences between these with dysplasia...... and controls in regard to age, body mass index or occupational exposure to daily repeated lifting at admission.We found no significant differences in the reduction of the joint space width at follow-up between subjects with dysplasia and the control subjects nor in self-reported pain in the hip......In a longitudinal case-control study, we followed 81 subjects with dysplasia of the hip and 136 control subjects without dysplasia for ten years assessing radiological evidence of degeneration of the hip at admission and follow-up. There were no cases of subluxation in the group with dysplasia...

  17. Optimizing the width of strip weeding in arabica coffee in relation to crop age Largura da faixa de controle de plantas daninhas em café arábica em função da idade do cafeeiro

    Directory of Open Access Journals (Sweden)

    FC. Araújo

    2012-03-01

    Full Text Available The aim of this study was to determine the weed strip control (WSC required for adequate coffee growth after transplanting. A non-irrigated, field-planted (spaced 3.80 x 0.70 m crop was used. The experimental design was a randomized block, with four replicates. The treatments were arranged in a 9 x 18 split-plot design to test the WSC of 0, 15, 30, 45, 60, 90, 120, 150, and 190 cm, which involved continuously hand-weeding at each side of the coffee row, and 18 coffee growth measurements. Multiple regression analyses were carried out relating to growth-variables as a function of both WSC and growth-evaluation times. Brachiaria decumbens was the main weed accomplishing 88.5% of the total weed dry mass. The minimum width of the WSC increases as the crop ages after transplanting. Assuming reductions of 2% and 5% in the maximum coffee growth, the recommended WSC was 75 and 52 cm at 4 months after transplanting (MAT, 104 and 85 cm at 6 MAT, 123 and 105 cm at 9 MAT, 134 and 116 cm at 12 MAT, 142 and 124 cm at 15 MAT, and 148 and 131 cm at 18 MAT, respectively. It was concluded that integrated weed management in young coffee crops must focus on the weed control only in a minimum range along coffee rows, which increases with coffee plant age, keeping natural vegetation in the inter-rows.O objetivo deste estudo consistiu em determinar a faixa ideal de controle de plantas daninhas (FCPD necessária para um crescimento adequado do cafeeiro após o transplantio. Foi utilizada uma lavoura não irrigada, implantada no espaçamento de 3,80 x 0,70 m, em dezembro de 2008. O delineamento experimental foi em blocos casualizados, com quatro repetições. Os tratamentos foram dispostos em um esquema de parcelas subdivididas (9 x 18 para testar as FCPDs de 0, 15, 30, 45, 60, 90, 120, 150 e 190 cm, mantidas com capina contínua em cada lado da linha de café, bem como seus efeitos ao longo de 18 meses após o transplantio (MAT. Efetuaram-se análises de regressão m

  18. PERFORMANCE EVALUATION OF THREE PHASE SCALAR CONTROLLED PWM RECTIFIER USING DIFFERENT CARRIER AND MODULATING SIGNAL

    Directory of Open Access Journals (Sweden)

    J. CHELLADURAI

    2015-04-01

    Full Text Available Power quality problems caused by significant increase of non-linear loads initiated intensive research in high power factor converters. Most of the modern power electronic systems like variable speed drives, DC power supplies and battery charging systems uses uncontrolled diode bridge rectifier. The uncontrolled rectifier system injects lot of harmonics in to the AC supply system there by reducing the power factor to less than unity. Single stage PWM rectifier is the novel solution to eliminate the harmonics and to improve the input power factor. In this paper, a scalar controlled PWM rectifier is modeled and the system is compared with the conventional bridge rectifier with and without filter.The major advantages of using this technique are less intensive computational control and sensor less input voltage operation. The PWM rectifier system is investigated using the different carrier and modulating signal. The scalar control technique is used to control the boost rectifier output voltage and input power factor. The performance of the rectifier with different carrier and modulating techniques were compared with respect to the Total Harmonic Distortion (THD in source current. Simulation results demonstrate the effectiveness of the modified modulating signal and triangular carrier signal for effectively reducing the source current THD.

  19. Central nervous system control of gastrointestinal motility and secretion and modulation of gastrointestinal functions.

    Science.gov (United States)

    Browning, Kirsteen N; Travagli, R Alberto

    2014-10-01

    Although the gastrointestinal (GI) tract possesses intrinsic neural plexuses that allow a significant degree of autonomy over GI functions, the central nervous system (CNS) provides extrinsic neural inputs that regulate, modulate, and control these functions. While the intestines are capable of functioning in the absence of extrinsic inputs, the stomach and esophagus are much more dependent upon extrinsic neural inputs, particularly from parasympathetic and sympathetic pathways. The sympathetic nervous system exerts a predominantly inhibitory effect upon GI muscle and provides a tonic inhibitory influence over mucosal secretion while, at the same time, regulates GI blood flow via neurally mediated vasoconstriction. The parasympathetic nervous system, in contrast, exerts both excitatory and inhibitory control over gastric and intestinal tone and motility. Although GI functions are controlled by the autonomic nervous system and occur, by and large, independently of conscious perception, it is clear that the higher CNS centers influence homeostatic control as well as cognitive and behavioral functions. This review will describe the basic neural circuitry of extrinsic inputs to the GI tract as well as the major CNS nuclei that innervate and modulate the activity of these pathways. The role of CNS-centered reflexes in the regulation of GI functions will be discussed as will modulation of these reflexes under both physiological and pathophysiological conditions. Finally, future directions within the field will be discussed in terms of important questions that remain to be resolved and advances in technology that may help provide these answers.

  20. Temporally Dissociable Mechanisms of Self-Control: Early Attentional Filtering Versus Late Value Modulation

    Science.gov (United States)

    Hare, Todd; Rangel, Antonio

    2013-01-01

    Optimal decision-making often requires exercising self-control. A growing fMRI literature has implicated the dorsolateral prefrontal cortex (dlPFC) in successful self-control, but due to the limitations inherent in BOLD measures of brain activity, the neurocomputational role of this region has not been resolved. Here we exploit the high temporal resolution and whole-brain coverage of event-related potentials (ERPs) to test the hypothesis that dlPFC affects dietary self-control through two different mechanisms: attentional filtering and value modulation. Whereas attentional filtering of sensory input should occur early in the decision process, value modulation should occur later on, after the computation of stimulus values begins. Hungry human subjects were asked to make food choices while we measured neural activity using ERP in a natural condition, in which they responded freely and did not exhibit a tendency to regulate their diet, and in a self-control condition, in which they were given a financial incentive to lose weight. We then measured various neural markers associated with the attentional filtering and value modulation mechanisms across the decision period to test for changes in neural activity during the exercise of self-control. Consistent with the hypothesis, we found evidence for top-down attentional filtering early on in the decision period (150–200 ms poststimulus onset) as well as evidence for value modulation later in the process (450–650 ms poststimulus onset). We also found evidence that dlPFC plays a role in the deployment of both mechanisms. PMID:24285897

  1. Pulse-modulated dual-gas control subsystem for space cabin atmosphere

    Science.gov (United States)

    Jackson, J. K.

    1974-01-01

    An atmosphere control subsystem (ACS) was developed for use in a closed manned cabin, such as the Space Shuttle Orbiter. This subsystem uses the Perkin Elmer mass spectrometer for continuous measurement of major atmospheric constituents (H2, H2O, N2, O2, and CO2). The O2 and N2 analog signals are used as inputs to the controller, which produces a pulse-frequency-modulated output to operate the N2 gas admission solenoid valve and an on-off signal to operate the O2 valve. The proportional controller characteristic results in improved control accuracy as compared with previously used on-off controllers having significant dead-band. A 60-day evaluation test was performed on the ACS during which operation was measured at various values of control setpoint and simulated cabin leakage.

  2. Performance Evaluation of a High Bandwidth Liquid Fuel Modulation Valve for Active Combustion Control

    Science.gov (United States)

    Saus, Joseph R.; DeLaat, John C.; Chang, Clarence T.; Vrnak, Daniel R.

    2012-01-01

    At the NASA Glenn Research Center, a characterization rig was designed and constructed for the purpose of evaluating high bandwidth liquid fuel modulation devices to determine their suitability for active combustion control research. Incorporated into the rig s design are features that approximate conditions similar to those that would be encountered by a candidate device if it were installed on an actual combustion research rig. The characterized dynamic performance measures obtained through testing in the rig are planned to be accurate indicators of expected performance in an actual combustion testing environment. To evaluate how well the characterization rig predicts fuel modulator dynamic performance, characterization rig data was compared with performance data for a fuel modulator candidate when the candidate was in operation during combustion testing. Specifically, the nominal and off-nominal performance data for a magnetostrictive-actuated proportional fuel modulation valve is described. Valve performance data were collected with the characterization rig configured to emulate two different combustion rig fuel feed systems. Fuel mass flows and pressures, fuel feed line lengths, and fuel injector orifice size was approximated in the characterization rig. Valve performance data were also collected with the valve modulating the fuel into the two combustor rigs. Comparison of the predicted and actual valve performance data show that when the valve is operated near its design condition the characterization rig can appropriately predict the installed performance of the valve. Improvements to the characterization rig and accompanying modeling activities are underway to more accurately predict performance, especially for the devices under development to modulate fuel into the much smaller fuel injectors anticipated in future lean-burning low-emissions aircraft engine combustors.

  3. Controlling Mobility in Perovskite Oxides by Ferroelectric Modulation of Atomic-Scale Interface Structure.

    Science.gov (United States)

    Malashevich, Andrei; Marshall, Matthew S J; Visani, Cristina; Disa, Ankit S; Xu, Haichao; Walker, Frederick J; Ahn, Charles H; Ismail-Beigi, Sohrab

    2017-12-26

    Coherent and epitaxial interfaces permit the realization of electric field driven devices controlled by atomic-scale structural and electronic effects at interfaces. Compared to conventional field effect devices where channel conductivity is modulated by carrier density modification, the propagation of atomic-scale distortions across an interface can control the atomic scale bonding, interatomic electron tunneling rates and thus the mobility of the channel material. We use first-principles theory to design an atomically abrupt epitaxial perovskite heterostructure involving an oxide ferroelectric (PbZr0.2Ti0.8O3) and conducting oxide channel (LaNiO3) where coupling of polar atomic motions to structural distortions can induce large, reversible changes in the channel mobility. We fabricate and characterize the heterostructure and measure record values, larger than 1000%, for the conductivity modulation. Our results describe how purely interfacial effects can be engineered to deliver unique electronic device properties and large responses to external fields.

  4. Quantum well saturable absorber mirror with electrical control of modulation depth

    DEFF Research Database (Denmark)

    Liu, Xiaomin; Rafailov, Edik U.; Livshits, Daniil

    2010-01-01

    We demonstrate a quantum well QW semiconductor saturable absorber mirror SESAM comprising low-temperature grown InGaAs/GaAs QWs incorporated into a p-i-n structure. By applying the reverse bias voltage in the range 0–2 V to the p-i-n structure, we were able to change the SESAM modulation depth...... in the range 2.5–0.5%, as measured by nonlinear reflectivity of 450 fs long laser pulses with 1065 nm central wavelength, in the pump fluence range 1.6–26.7 J /cm2. This electrical control of the modulation depth is achieved by controlling the small-signal loss of the SESAM via quantum-confined Stark effect...

  5. Discontinuous PWM Modulation Strategy with Circuit-Level Decoupling Concept of Three-Level Neutral-Point Clamped (NPC) Inverter

    DEFF Research Database (Denmark)

    Zhang, Zhe; Thomsen, Ole Cornelius; Andersen, Michael A. E.

    2013-01-01

    A new pulse width modulation (PWM) strategy which is an alternative approach of discontinuous PWM (DPWM) for a three-level neutral point clamped (NPC) inverter is developed and presented in this paper. The proposed PWM scheme not only takes advantage of the special properties available in NPC...... can be simplified. The salient features of the proposed scheme, as compared with the existing carrier-based DPWM strategies, are: 1) its reduced computational processing time, 2) its capability to balance the DC-link voltage without any additional control and 3) its reduced complexity e.g. only one...... carrier wave needed for pulse width modulating. Same as a space vector modulation, the maximum modulation index, 1.1547, can be attainable by the proposed scheme. Moreover, compared to conventional continuous sinusoidal pulse width modulation, using this technique here the switching losses of the devices...

  6. Coherent Control of Photofragment Distributions Using Laser Phase Modulation in the Weak-Field Limit

    DEFF Research Database (Denmark)

    Garcia-Vela, Alberto; Henriksen, Niels Engholm

    2015-01-01

    The possibility of quantum interference control of the final state distributions of photodissociation fragments by means of pure phase modulation of the pump laser pulse in the weak-field regime is demonstrated theoretically for the first time. The specific application involves realistic wave...... to persist for long times (about 200 ps) after the pulse is over due to interference between overlapping resonances in Ne-Br-2(B)....

  7. Surface modification and modulation in microstructures: controlling protein adsorption, monolayer desorption and micro-self-assembly

    Science.gov (United States)

    Böhringer, Karl F.

    2003-07-01

    The surface-to-volume ratio increases with decreasing scale, thus, controlling and changing the surface properties of microstructures can be a powerful tool in the design, fabrication and use of microsystems. This paper overviews several recent projects that utilize the modulation of surfaces from hydrophobic to hydrophilic and vice versa, or from protein adsorbing to non-fouling, with applications in biomedical microdevices and self-assembling microelectromechanical systems.

  8. Central Nervous System Control of Gastrointestinal Motility and Secretion and Modulation of Gastrointestinal Functions

    OpenAIRE

    Browning, Kirsteen N.; Travagli, R. Alberto

    2014-01-01

    Although the gastrointestinal (GI) tract possesses intrinsic neural plexuses that allow a significant degree of autonomy over GI functions, the central nervous system (CNS) provides extrinsic neural inputs that regulate, modulate, and control these functions. While the intestines are capable of functioning in the absence of extrinsic inputs, the stomach and esophagus are much more dependent upon extrinsic neural inputs, particularly from parasympathetic and sympathetic pathways. The sympathet...

  9. Performance analysis of joint diversity combining, adaptive modulation, and power control schemes

    KAUST Repository

    Qaraqe, Khalid A.

    2011-01-01

    Adaptive modulation and diversity combining represent very important adaptive solutions for future generations of wireless communication systems. Indeed, in order to improve the performance and the efficiency of these systems, these two techniques have been recently used jointly in new schemes named joint adaptive modulation and diversity combining (JAMDC) schemes. Considering the problem of finding low hardware complexity, bandwidth-efficient, and processing-power efficient transmission schemes for a downlink scenario and capitalizing on some of these recently proposed JAMDC schemes, we propose and analyze in this paper three joint adaptive modulation, diversity combining, and power control (JAMDCPC) schemes where a constant-power variable-rate adaptive modulation technique is used with an adaptive diversity combining scheme and a common power control process. More specifically, the modulation constellation size, the number of combined diversity paths, and the needed power level are jointly determined to achieve the highest spectral efficiency with the lowest possible processing power consumption quantified in terms of the average number of combined paths, given the fading channel conditions and the required bit error rate (BER) performance. In this paper, the performance of these three JAMDCPC schemes is analyzed in terms of their spectral efficiency, processing power consumption, and error-rate performance. Selected numerical examples show that these schemes considerably increase the spectral efficiency of the existing JAMDC schemes with a slight increase in the average number of combined paths for the low signal-to-noise ratio range while maintaining compliance with the BER performance and a low radiated power which yields to a substantial decrease in interference to co-existing users and systems. © 2011 IEEE.

  10. New controller for high voltage converter modulator at spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Wezensky, Mark W [ORNL; Brown, David L [ORNL; Lee, Sung-Woo [ORNL; Zhukov, Alexander P [ORNL; Geng, Xiaosong [ORNL

    2017-01-01

    The Spallation Neutron Source (SNS) has developed a new control system for the High Voltage Convertor Modulator (HVCM) at the SNS to replace the original control system which is approaching obsolescence. The original system was based on controllers for similar high voltage systems that were already in use [1]. The new controller, based on National Instruments PXI/FlexRIO Field Programmable Gate Array (FPGA) platform, offers enhancements such as modular construction, flexibility and non-proprietary software. The new controller also provides new capabilities like various methods for modulator pulse flattening, waveform capture, and first fault detection. This paper will discuss the design of the system, including the human machine interface, based on lessons learned at the SNS and other projects. It will also discuss performance and other issues related to its operation in an accelerator facility which requires high availability. To date, 73% of the operational HVCMs have been upgraded to with the new controller, and the remainder are scheduled for completion by mid-2017.

  11. Real-Time Performance of Mechatronic PZT Module Using Active Vibration Feedback Control.

    Science.gov (United States)

    Aggogeri, Francesco; Borboni, Alberto; Merlo, Angelo; Pellegrini, Nicola; Ricatto, Raffaele

    2016-09-25

    This paper proposes an innovative mechatronic piezo-actuated module to control vibrations in modern machine tools. Vibrations represent one of the main issues that seriously compromise the quality of the workpiece. The active vibration control (AVC) device is composed of a host part integrated with sensors and actuators synchronized by a regulator; it is able to make a self-assessment and adjust to alterations in the environment. In particular, an innovative smart actuator has been designed and developed to satisfy machining requirements during active vibration control. This study presents the mechatronic model based on the kinematic and dynamic analysis of the AVC device. To ensure a real time performance, a H2-LQG controller has been developed and validated by simulations involving a machine tool, PZT actuator and controller models. The Hardware in the Loop (HIL) architecture is adopted to control and attenuate the vibrations. A set of experimental tests has been performed to validate the AVC module on a commercial machine tool. The feasibility of the real time vibration damping is demonstrated and the simulation accuracy is evaluated.

  12. Radiative widths of neutral kaon excitations

    Indian Academy of Sciences (India)

    we limit the radiative widths Γr(K*(1410)) and Γr(K*. 2(1430)) to 52.9 and 5.4 keV, respectively, at 90% CL. While there is no prediction for Γr(K*(1410)), Babcock and Rosner [9] used SU(3) invariance to predict that excitations with JPC = 1++ or 2++ would have vanishing radiative widths. In the limit of SU(3), K*. 2(1430) has.

  13. Control system for the carburettor of an internal combustion engine. Steuerungssystem fuer den Vergaser einer Brennkraftmaschine

    Energy Technology Data Exchange (ETDEWEB)

    Erhard, W.; Fluegel, W.

    1991-02-14

    Control system for the carburettor of an internal combustion engine, especially lawn-movers, powersaws or cutoff machines. At the entrance of the carburettor induction pipe there is a pre-throttle valve which is automatically operated by an actuator. The actuator can be operated by a pulse-width modulator whose pulse width or degree of modulation is influenced by a stored-program family of curves which generates signals for pre-specified fuel-air mixtures depending on the machine speed and sends these signals to the pulse-width modulator.

  14. Fully interferometric controllable anomalous refraction efficiency using cross modulation with plasmonic metasurfaces.

    Science.gov (United States)

    Liu, Zhaocheng; Chen, Shuqi; Li, Jianxiong; Cheng, Hua; Li, Zhancheng; Liu, Wenwei; Yu, Ping; Xia, Ji; Tian, Jianguo

    2014-12-01

    We present a method of fully interferometric, controllable anomalous refraction efficiency by introducing cross-modulated incident light based on plasmonic metasurfaces. Theoretical analyses and numerical simulations indicate that the anomalous and ordinary refracted beams generated from two opposite-helicity incident beams and following the generalized Snell's law will have a superposition for certain incident angles, and the anomalous refraction efficiency can be dynamically controlled by changing the relative phase of the incident sources. As the incident wavelength nears the resonant wavelength of the plasmonic metasurfaces, two equal-amplitude incident beams with opposite helicity can be used to control the anomalous refraction efficiency. Otherwise, two unequal-amplitude incident beams with opposite helicity can be used to fully control the anomalous refraction efficiency. This Letter may offer a further step in the development of controllable anomalous refraction.

  15. FPGA Based V/f Control of Three Phase Induction Motor Drives Integrating Super-Lift Luo Converter

    National Research Council Canada - National Science Library

    Elangovan P; Nalin Kant Mohanty

    2015-01-01

    .... The Voltage Source Inverter (VSI) of the suggested system renders both open loop and closed loop V/f control scheme for IM by feedback regulated Sinusoidal Pulse Width Modulation (SPWM) technique...

  16. Grid Voltage Modulated Control of Grid-Connected Voltage Source Inverters under Unbalanced Grid Conditions

    DEFF Research Database (Denmark)

    Li, Mingshen; Gui, Yonghao; Quintero, Juan Carlos Vasquez

    2017-01-01

    In this paper, an improved grid voltage modulated control (GVM) with power compensation is proposed for grid-connected voltage inverters when the grid voltage is unbalanced. The objective of the proposed control is to remove the power ripple and to improve current quality. Three power compensation...... objectives are selected to eliminate the negative sequence components of currents. The modified GVM method is designed to obtain two separate second-order systems for not only the fast convergence rate of the instantaneous active and reactive powers but also the robust performance. In addition, this method...

  17. A Chaotic Pulse-Time Modulation Method for Digital Communication

    OpenAIRE

    Nguyen Xuan Quyen; Vu Van Yem; Thang Manh Hoang

    2012-01-01

    We present and investigate a method of chaotic pulse-time modulation (PTM) named chaotic pulse-width-position modulation (CPWPM) which is the combination of pulse-position-modulation (PPM) and pulse-width modulation (PWM) with the inclusion of chaos technique for digital communications. CPWPM signal is in the pulse train format, in which binary information is modulated onto chaotically-varied intervals of position and width of pulses, and therefore two bits are encoded on a single pulse. The ...

  18. Pulsed lasers in speckle photography: error owing to pulse width.

    Science.gov (United States)

    Joenathan, C; Blair, S M; Ganesan, A R

    1993-01-10

    The effect of the pulse width of a pulsed laser in the studies of speckle velocimetry and transient vibration analysis is discussed. Because of the motion of the object during an exposure, a sine function is obtained by using the pointwise filtering method. This function modulates the halo along with the Young's fringes. It is shown that for high object velocities the sinc function modifies the halo distribution; as a result, the error in calculating the fringe position increases. An aperture geometry for which the autocorrelation halo is made constant in certain regions is proposed in which the intensity variation in this region is the result of the modulating sinc function only. A closed-form solution for the shift in the position of the fringes in this region is obtained. Experimental results of the simulation are presented.

  19. Automation of testing modules of controller ELSY-ТМК

    Science.gov (United States)

    Dolotov, A. E.; Dolotova, R. G.; Petuhov, D. V.; Potapova, A. P.

    2017-01-01

    In modern life, there are means for automation of various processes which allow one to provide high quality standards of released products and to raise labour efficiency. In the given paper, the data on the automation of the test process of the ELSY-TMK controller [1] is presented. The ELSY-TMK programmed logic controller is an effective modular platform for construction of automation systems for small and average branches of industrial production. The modern and functional standard of communication and open environment of the logic controller give a powerful tool of wide spectrum applications for industrial automation. The algorithm allows one to test controller modules by operating the switching system and external devices faster and at a higher level of quality than a human without such means does.

  20. Application handbook for a Standardized Control Module (SCM) for DC-DC converters, volume 1

    Science.gov (United States)

    Lee, F. C.; Mahmoud, M. F.; Yu, Y.

    1980-01-01

    The standardized control module (SCM) was developed for application in the buck, boost and buck/boost DC-DC converters. The SCM used multiple feedback loops to provide improved input line and output load regulation, stable feedback control system, good dynamic transient response and adaptive compensation of the control loop for changes in open loop gain and output filter time constraints. The necessary modeling and analysis tools to aid the design engineer in the application of the SCM to DC-DC Converters were developed. The SCM functional block diagram and the different analysis techniques were examined. The average time domain analysis technique was chosen as the basic analytical tool. The power stage transfer functions were developed for the buck, boost and buck/boost converters. The analog signal and digital signal processor transfer functions were developed for the three DC-DC Converter types using the constant on time, constant off time and constant frequency control laws.

  1. Modulated Magnetic Nanowires for Controlling Domain Wall Motion: Toward 3D Magnetic Memories

    KAUST Repository

    Ivanov, Yurii P.

    2016-05-03

    Cylindrical magnetic nanowires are attractive materials for next generation data storage devices owing to the theoretically achievable high domain wall velocity and their efficient fabrication in highly dense arrays. In order to obtain control over domain wall motion, reliable and well-defined pinning sites are required. Here, we show that modulated nanowires consisting of alternating nickel and cobalt sections facilitate efficient domain wall pinning at the interfaces of those sections. By combining electron holography with micromagnetic simulations, the pinning effect can be explained by the interaction of the stray fields generated at the interface and the domain wall. Utilizing a modified differential phase contrast imaging, we visualized the pinned domain wall with a high resolution, revealing its three-dimensional vortex structure with the previously predicted Bloch point at its center. These findings suggest the potential of modulated nanowires for the development of high-density, three-dimensional data storage devices. © 2016 American Chemical Society.

  2. Control strategy for Single-phase Transformerless Three-leg Unified Power Quality Conditioner Based on Space Vector Modulation

    DEFF Research Database (Denmark)

    Lu, Yong; Xiao, Guochun; Wang, Xiongfei

    2016-01-01

    The unified power quality conditioner (UPQC) is known as an effective compensation device to improve PQ for sensitive end-users. This paper investigates the operation and control of a single-phase three-leg UPQC (TL-UPQC), where a novel space vector modulation method is proposed for naturally...... solving the coupling problem introduced by the common switching leg. The modulation method is similar to the well-known space vector modulation widely used with three-phase voltage source converters, which thus brings extra flexibility to the TL-UPQC system. Two optimized modulation modes with either...

  3. Comparative analysis of modulation and demodulation methods of the control signals of rail line

    Directory of Open Access Journals (Sweden)

    K.V.Goncharov

    2012-12-01

    Full Text Available Introduction: One of the ways of increasing the noise stability rail circuit is the use more informative waveform of control signal. Use in rail circuit modulated signals gives several informative selective traits in relatively narrow spectrum. The study of features of various modulation and demodulation methods with considering operating conditions of rail circuits is urgent. Purpose: the search for more informative forms of rail line control signal, the search for improved methods of signal processing of control current. Methods: For carrying out researches the method of signals decomposition in Fourier series and the simulation with the method of statistical tests have been sed. Results: Spectrum of frequency shift signal is wider than the spectrum of amplitude shift and phase shift signals by an amount equal to twice the frequency deviation. The research of correlation coherent and incoherent reception methods of rail line control signal has been carried out. In this case, we used the following models of interferences: white Gaussian noise, random pulse sequence and sinusoidal interference. It has been found that the transition from amplitude to frequency shift keying reduces signal/noise ratio by 2...4 dB, depending from the signal level and the type of noise. Losing amplitude shift keying receiver compared with the phase shift keying receiver is 5...6 dB. Conclusions: The use of more advanced methods of modulation and demodulation improves noise stability of rail circuit. When using correlation methods reception phase shift keying provides the best noise stability, and amplitude – the worst.

  4. Executive control modulates cross-language lexical activation during L2 reading: evidence from eye movements.

    Science.gov (United States)

    Pivneva, Irina; Mercier, Julie; Titone, Debra

    2014-05-01

    Models of bilingual reading such as Bilingual Interactive Activation Plus (Dijkstra & van Heuven, 2002) do not predict a central role for domain-general executive control during bilingual reading, in contrast with bilingual models from other domains, such as production (e.g., the Inhibitory Control Model; Green, 1998). We thus investigated whether individual differences among bilinguals in domain-general executive control modulate cross-language activation during L2 sentence reading, over and above other factors such as L2 proficiency. Fifty French-English bilinguals read L2-English sentences while their eye movements were recorded, and they subsequently completed a battery of executive control and L2 proficiency tasks. High- and low-constraint sentences contained interlingual homographs (chat = "casual conversation" in English, "a cat" in French), cognates (piano in English and French), or L2-specific control words. The results showed that greater executive control among bilinguals but not L2 proficiency reduced cross-language activation in terms of interlingual homograph interference. In contrast, increased L2 proficiency but not executive control reduced cross-language activation in terms of cognate facilitation. These results suggest that models of bilingual reading must incorporate mechanisms by which domain-general executive control can alter the earliest stages of bilingual lexical activation. PsycINFO Database Record (c) 2014 APA, all rights reserved.

  5. Effect of stimulus width on simultaneous contrast

    Directory of Open Access Journals (Sweden)

    Veronica Shi

    2013-09-01

    Full Text Available Perceived brightness of a stimulus depends on the background against which the stimulus is set, a phenomenon known as simultaneous contrast. For instance, the same gray stimulus can look light against a black background or dark against a white background. Here we quantified the perceptual strength of simultaneous contrast as a function of stimulus width. Previous studies have reported that wider stimuli result in weaker simultaneous contrast, whereas narrower stimuli result in stronger simultaneous contrast. However, no previous research has quantified this relationship. Our results show a logarithmic relationship between stimulus width and perceived brightness. This relationship is well matched by the normalized output of a Difference-of-Gaussians (DOG filter applied to stimuli of varied widths.

  6. Preequilibrium escape widths of giant resonances

    Science.gov (United States)

    Roos, M. O.; Dias, H.; Rodriguez, O.; Teruya, N.; Hussein, M. S.

    2002-08-01

    In this work we present a calculation of the 2p-2h preequilibrium escape width of giant resonances for the nuclei 40Ca, 90Zr, and 208Pb. The problem studied here involves an excited nucleus in the 1p-1h configuration, evolving to the 2p-2h configuration with the 1p in the continuum. The theoretical approach used for our calculations is based on the statistical multistep compound theory of Feshbach, Kerman, and Koonin (FKK) and on the particle-hole state densities given by Obložinský. Our calculations show that although different state densities supply a similar result for the damping width, the escape width is strongly dependent on the nuclei, on the binding energy of the emitted nucleon, and the excitation energy of the giant resonance.

  7. A ballistics module as a part of the fire control system

    Directory of Open Access Journals (Sweden)

    Branka R. Luković

    2013-10-01

    Full Text Available This article presents a ballistics module as a part of the fire control system of weapons for fire support (mortars, artillery weapons and rocket launchers. The software is "open" with the prominence of autonomy work. It can be modulated and adapted on the user demand. Moreover, it is independent of the hardware base. Introduction: The fire control system is based on a ballistic module (BM which determines the firing data for each weapon tool in the battery. Ballistic calculations, for the given position of the target in relation to the position of tools in the given weather conditions, determine firing data (elevation, direction, timing and locating devices so that the missile seems to cause the desired effect. This paper gives the basic information about the features the BM performs and the manner of their implementation in the fire control system without going into algorithmic solution procedures. Ballistic problem in the fire control system: Ballistic calculation is based on a trajectory calculation of all kinds of projectiles (current, time-fuze, illuminating, smoke, with conventional propulsion, rocket, with built-in gas generator, etc.. Instead of previous solutions, where a trajectory calculation of the fire control system was done by approximate methods, in this BM the trajectory calculation is made by the same model with the same data as for a weapon and ammunition in the process of creating a firing table. The data used in the fire control system are made simultaneously with the preparation of firing tables for a particular tool and associated ammunition,. A modified model of particle, standardized at the NATO level, is also used. Taking into account the meteorological situation, before the trajectory calculation is done, a relative position of the target in relation to the position of the tool should be determined. A selection or loading check is carried out (possibility of reaching a given target as well as the point at which the

  8. Proton mediated control of biochemical reactions with bioelectronic pH modulation

    Science.gov (United States)

    Deng, Yingxin; Miyake, Takeo; Keene, Scott; Josberger, Erik E.; Rolandi, Marco

    2016-04-01

    In Nature, protons (H+) can mediate metabolic process through enzymatic reactions. Examples include glucose oxidation with glucose dehydrogenase to regulate blood glucose level, alcohol dissolution into carboxylic acid through alcohol dehydrogenase, and voltage-regulated H+ channels activating bioluminescence in firefly and jellyfish. Artificial devices that control H+ currents and H+ concentration (pH) are able to actively influence biochemical processes. Here, we demonstrate a biotransducer that monitors and actively regulates pH-responsive enzymatic reactions by monitoring and controlling the flow of H+ between PdHx contacts and solution. The present transducer records bistable pH modulation from an “enzymatic flip-flop” circuit that comprises glucose dehydrogenase and alcohol dehydrogenase. The transducer also controls bioluminescence from firefly luciferase by affecting solution pH.

  9. Analysis and design of a standardized control module for switching regulators

    Science.gov (United States)

    Lee, F. C.; Mahmoud, M. F.; Yu, Y.; Kolecki, J. C.

    1982-01-01

    Three basic switching regulators: buck, boost, and buck/boost, employing a multiloop standardized control module (SCM) were characterized by a common small signal block diagram. Employing the unified model, regulator performances such as stability, audiosusceptibility, output impedance, and step load transient are analyzed and key performance indexes are expressed in simple analytical forms. More importantly, the performance characteristics of all three regulators are shown to enjoy common properties due to the unique SCM control scheme which nullifies the positive zero and provides adaptive compensation to the moving poles of the boost and buck/boost converters. This allows a simple unified design procedure to be devised for selecting the key SCM control parameters for an arbitrarily given power stage configuration and parameter values, such that all regulator performance specifications can be met and optimized concurrently in a single design attempt.

  10. Dual-light control of nanomachines that integrate motor and modulator subunits

    Science.gov (United States)

    Foy, Justin T.; Li, Quan; Goujon, Antoine; Colard-Itté, Jean-Rémy; Fuks, Gad; Moulin, Emilie; Schiffmann, Olivier; Dattler, Damien; Funeriu, Daniel P.; Giuseppone, Nicolas

    2017-07-01

    A current challenge in the field of artificial molecular machines is the synthesis and implementation of systems that can produce useful work when fuelled with a constant source of external energy. The first experimental achievements of this kind consisted of machines with continuous unidirectional rotations and translations that make use of 'Brownian ratchets' to bias random motions. An intrinsic limitation of such designs is that an inversion of directionality requires heavy chemical modifications in the structure of the actuating motor part. Here we show that by connecting subunits made of both unidirectional light-driven rotary motors and modulators, which respectively braid and unbraid polymer chains in crosslinked networks, it becomes possible to reverse their integrated motion at all scales. The photostationary state of the system can be tuned by modulation of frequencies using two irradiation wavelengths. Under this out-of-equilibrium condition, the global work output (measured as the contraction or expansion of the material) is controlled by the net flux of clockwise and anticlockwise rotations between the motors and the modulators.

  11. A Hierarchical Control Architecture for a PEBB-Based ILC Marx Modulator

    Energy Technology Data Exchange (ETDEWEB)

    Macken, K.; Burkhart, C.; Larsen, R.; Nguyen, M.N.; Olsen, J.; /SLAC

    2011-12-15

    The idea of building power conversion systems around Power Electronic Building Blocks (PEBBs) was initiated by the U.S. Office of Naval Research in the mid 1990s. A PEBB-based design approach is advantageous in terms of power density, modularity, reliability, and serviceability. It is obvious that this approach has much appeal for pulsed power conversion including the International Linear Collider (ILC) klystron modulator application. A hierarchical control architecture has the inherent capability to support the integration of PEBBs. This has already been successfully demonstrated in a number of industrial applications in the recent past. This paper outlines the underlying concepts of a hierarchical control architecture for a PEBB-based Marx-topology ILC klystron modulator. The control in PEBB-based power conversion systems can be functionally partitioned into (three) hierarchical layers; system layer, application layer, and PEBB layer. This has been adopted here. Based on such a hierarchical partition, the interfaces are clearly identified and defined and, consequently, are easily characterised. A conceptual design of the hardware manager, executing low-level hardware oriented tasks, is detailed. In addition, the idea of prognostics is briefly discussed.

  12. Standardized modulation of the injection site allows for insulin dose reduction without deterioration of metabolic control.

    Science.gov (United States)

    Pfützner, A; Dissel, S; Forkel, C; Grenningloh, M; Bitton, G; Nagar, R; Forst, T

    2014-10-01

    Use of an injection site modulation device (InsuPad) in intensive insulin treatment reduces frequency of hypoglycemia and prandial insulin requirements by enhancing subcutaneous microcirculation. This meal tolerance test (MTT) investigation was performed as a sub-study during the real-world BARMER study to demonstrate non-inferiority of the reduced insulin doses observed in this study with respect to metabolic control. The MTT was performed at baseline and after 3 months in insulin treated diabetes patients using the modulation device vs. a control group without device. The dose used for the MTT was individually calculated based on the prandial insulin records from the patient diaries before the test. Blood was drawn for determination of glucose, insulin, C-peptide, proinsulin, triglycerides, free fatty acids, nitrotyrosine, and asymmetric dimethyl-arginine (ADMA) at multiple time-points from 0 to 300 min. A total of 32 patients from one site were included into this MTT study (8 female, 7 type 1 diabetes, age: 49.9 ± 12.5 yrs, HbA1c: 7.2 ± 0.5%). During the BARMER study, mean HbA1c was treated to target (control group (-0.1%, p metabolism.

  13. Precise control of superluminal and slow light propagation by transverse phase modulation.

    Science.gov (United States)

    Guedes, I; Misoguti, L; Zilio, S C

    2006-06-26

    We have used a heterodyne Z-scan technique to produce both superluminal and slow light propagation in media that present either thermal or Kerr nonlinearities. The sample position determines the magnitude and sign of the group velocity and this property was used to control it, with an experimental setup much simpler than those previously reported in similar investigations. The observed effect is attributed to the transverse phase modulation produced by a focused Gaussian beam, and is capable of producing both positive and negative group velocities in the range 1.5 m/s < |upsilon(g)| < c.

  14. Association of Anterior Cruciate Ligament Width With Anterior Knee Laxity.

    Science.gov (United States)

    Wang, Hsin-Min; Shultz, Sandra J; Schmitz, Randy J

    2016-06-02

    Greater anterior knee laxity (AKL) has been identified as an anterior cruciate ligament (ACL) injury risk factor. The structural factors that contribute to greater AKL are not fully understood but may include the ACL and bone geometry. To determine the relationship of ACL width and femoral notch angle to AKL. Cross-sectional study. Controlled laboratory. Twenty recreationally active females (age = 21.2 ± 3.1 years, height = 1.66.1 ± 7.3 cm, mass = 66.5 ± 12.0 kg). Anterior cruciate ligament width and femoral notch angle were obtained with magnetic resonance imaging of the knee and AKL was assessed. Anterior cruciate ligament width was measured as the width of a line that transected the ACL and was drawn perpendicular to the Blumensaat line. Femoral notch angle was formed by the intersection of the line parallel to the posterior cortex of the femur and the Blumensaat line. Anterior knee laxity was the anterior displacement of the tibia relative to the femur (mm) at 130 N of an applied force. Ten participants' magnetic resonance imaging data were assessed on 2 occasions to establish intratester reliability and precision. Using stepwise backward linear regression, we examined the extent to which ACL width, femoral notch angle, and weight were associated with AKL. Strong measurement consistency and precision (intraclass correlation coefficient [2,1] ± SEM) were established for ACL width (0.98 ± 0.3 mm) and femoral notch angle (0.97° ± 1.1°). The regression demonstrated that ACL width (5.9 ± 1.4 mm) was negatively associated with AKL (7.2 ± 2.0 mm; R(2) = 0.22, P = .04). Femoral notch angle and weight were not retained in the final model. A narrower ACL was associated with greater AKL. This finding may inform the development of ACL injury-prevention programs that include components designed to increase ACL size or strength (or both). Future authors should establish which other factors contribute to greater AKL in order to best inform injury-prevention efforts.

  15. Plug-in module acceleration feedback control for fast steering mirror-based beam stabilization systems

    Science.gov (United States)

    Deng, Chao; Ren, Wei; Mao, Yao; Ren, Ge

    2017-08-01

    A plug-in module acceleration feedback control (Plug-In AFC) strategy based on the disturbance observer (DOB) principle is proposed for charge-coupled device (CCD)-based fast steering mirror (FSM) stabilization systems. In classical FSM tracking systems, dual-loop control (DLC), including velocity feedback and position feedback, is usually utilized to enhance the closed-loop performance. Due to the mechanical resonance of the system and CCD time delay, the closed-loop bandwidth is severely restricted. To solve this problem, cascade acceleration feedback control (AFC), which is a kind of high-precision robust control method, is introduced to strengthen the disturbance rejection property. However, in practical applications, it is difficult to realize an integral algorithm in an acceleration controller to compensate for the quadratic differential contained in the FSM acceleration model, resulting in a challenging controller design and a limited improvement. To optimize the acceleration feedback framework in the FSM system, different from the cascade AFC, the accelerometers are used to construct DOB to compensate for the platform vibrations directly. The acceleration nested loop can be plugged into the velocity loop without changing the system stability, and the controller design is quite simple. A series of comparative experimental results demonstrate that the disturbance rejection property of the CCD-based FSM can be effectively improved by the proposed approach.

  16. An Active Heater Control Concept to Meet IXO Type Mirror Module Thermal-Structural Distortion Requirement

    Science.gov (United States)

    Choi, Michael

    2013-01-01

    Flight mirror assemblies (FMAs) of large telescopes, such as the International X-ray Observatory (IXO), have very stringent thermal-structural distortion requirements. The spatial temperature gradient requirement within a FMA could be as small as 0.05 C. Con ventionally, heaters and thermistors are attached to the stray light baffle (SLB), and centralized heater controllers (i.e., heater controller boards located in a large electronics box) are used. Due to the large number of heater harnesses, accommodating and routing them is extremely difficult. The total harness length/mass is very large. This innovation uses a thermally conductive pre-collimator to accommodate heaters and a distributed heater controller approach. It minimizes the harness length and mass, and reduces the problem of routing and accommodating them. Heaters and thermistors are attached to a short (4.67 cm) aluminum portion of the pre-collimator, which is thermally coupled to the SLB. Heaters, which have a very small heater power density, and thermistors are attached to the exterior of all the mirror module walls. The major portion (23.4 cm) of the pre-collimator for the middle and outer modules is made of thin, non-conductive material. It minimizes the view factors from the FMA and heated portion of the precollimator to space. It also minimizes heat conduction from one end of the FMA to the other. Small and multi-channel heater controllers, which have adjustable set points and internal redundancy, are used. They are mounted to the mechanical support structure members adjacent to each module. The IXO FMA, which is 3.3 m in diameter, is an example of a large telescope. If the heater controller boards are centralized, routing and accommodating heater harnesses is extremely difficult. This innovation has the following advantages. It minimizes the length/mass of the heater harness between the heater controllers and heater circuits. It reduces the problem of routing and accommodating the harness on the

  17. A Development of the Calibration Tool Applied on Analog I/O Modules for Safety-related Controller

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong-Kyun; Yun, Dong-Hwa; Lee, Myeong-Kyun; Yoo, Kwan-Woo [SOOSAN ENS Co., Seoul (Korea, Republic of)

    2016-10-15

    The purpose of this paper is to develop the calibration tool for analog input/output(I/O) modules. Those modules are components in POSAFE-Q which is a programmable logic controller(PLC) that has been developed for the evaluation of safety-related. In this paper, performance improvement of analog I/O modules is presented by developing and applying the calibration tool for each channel in analog I/O modules. With this tool, the input signal to an analog input module and the output signal from an analog output module are able to be satisfied with a reference value of sensor type and an accuracy of all modules. With RS-232 communication, the manual calibration tool is developed for analog I/O modules of an existing and up-to-date version in POSAFE-Q PLC. As a result of applying this tool, the converted value is performant for a type of input sensor and an accuracy of analog I/O modules.

  18. An efficient algorithm for equal width

    Science.gov (United States)

    Bakodah, Huda. O.; Banaja, Mona. A.

    2016-10-01

    The new modification of Laplace Adomian decomposition method (ADM) to obtain numerical solution of the equal width equation is presented. The performance of the method illustrated by solving some test examples of the problem. By computing the absolute error the results are found in good agreement with exact solution.

  19. Palindromic widths of nilpotent and wreath products

    Indian Academy of Sciences (India)

    and Research (IISER) Mohali, Knowledge City, Sector 81, S.A.S. Nagar,. P.O. Manauli 140 306, India. *Corresponding author. E-mail: bardakov@math.nsc.ru; ..... Logika 39(4) (2000) 395–440, translation in Algebra and Logic 39(4) (2000) 224–251. [4] Bardakov V G and Gongopadhyay K, Palindromic width of free nilpotent ...

  20. STUDIES AND EXPERIMENTAL RESEARCH CONCERNING THE PERFORMANCES OF THE INTERNAL COMBUSTION ENGINE, CONTROLLED OVER THE POWERTRAIN CONTROL MODULE

    Directory of Open Access Journals (Sweden)

    Narcis URICANU

    2012-05-01

    Full Text Available the paper present how can be controlled a road vehicle through a powertrain control module, a type of ECU, programmable ECU (Electronic Control Unit, when we want to increase the performances of the engine, compared with the standard performances of the engine. The programmable ECU is a control system which replaces the ECU from the vehicle and is able to manage, better than the standard ECU, the behaviour of the spark ignition engine on increasing the performances. Sports cars need to obtain the best performances from them engine, the specific regimes at which them must function impose certain limits which will be achieved during the competition. Nowadays the vehicles designers and engineering, working for the production cars, have adopted many solutions from the race cars area, due to the advantage offered by these elements (lightweight materials, fasts responses, high speeds and system like programmable ECU. To obtain more power on the engine, we have to find and applied the best solution concerning the internal combustion processes and the consequences concerning the exhaust. This papers present who can be increased the performances of the spark ignition engine through the air-flow ratio, controlled by the programmable ECU and with the sensors help, like water temperature sensor, intake air temperature sensor, throttle position sensor, lambda sensor

  1. Wireless inclinometer acquisition system for reducing swing movement control module experiment of hook model

    Science.gov (United States)

    Yu, Yan; Ou, Jinping; Zhang, Chunwei; Li, Luyu

    2008-03-01

    Large Scale Heavy Derrick Lay Barge is very important for sea work. Under intense wind and wave load, the hook on the Barge will vibrate so large that in some cases it can not work. Through installing the Tuned Mass Damper(TMD) on the hook, the vibration will be reduced to a certain range to meet the demand on sea work, which is also important for increasing the efficiency of sea work. To design the suitable TMD for the hook, the dynamical parameters should be specified beforehand. Generally, the related dynamical parameters such as inclinometer and acceleration are measured by wire sensors. But due to the restriction of the actual condition, the wire sensors are very hard to implement. Recently, the wireless sensors have been presented to overcome the shortcomings of wire ones. It is more suitable and also convenient to utilize wireless sensors to acquire the useful data of large scale heavy derrick lay barge. In this paper, the hook reducing swing movement control module is designed for large scale heavy derrick lay barge. Secondly, wireless inclinometer sensor system is integrated using the technique of MEMS, sensing and wireless communication. Finally, the hook reducing swing movement control module is validated by the developed wireless inclinometer data acquisition system. The wireless inclinometer sensor can be used not only in swing monitoring for large scale heavy derrick lay barge's Hook, but also in vibration monitoring for TV tower, large crane. In general, it has great application foreground.

  2. The Arabidopsis SWI/SNF protein BAF60 mediates seedling growth control by modulating DNA accessibility

    KAUST Repository

    Jégu, Teddy

    2017-06-15

    Plant adaptive responses to changing environments involve complex molecular interplays between intrinsic and external signals. Whilst much is known on the signaling components mediating diurnal, light, and temperature controls on plant development, their influence on chromatin-based transcriptional controls remains poorly explored.In this study we show that a SWI/SNF chromatin remodeler subunit, BAF60, represses seedling growth by modulating DNA accessibility of hypocotyl cell size regulatory genes. BAF60 binds nucleosome-free regions of multiple G box-containing genes, opposing in cis the promoting effect of the photomorphogenic and thermomorphogenic regulator Phytochrome Interacting Factor 4 (PIF4) on hypocotyl elongation. Furthermore, BAF60 expression level is regulated in response to light and daily rhythms.These results unveil a short path between a chromatin remodeler and a signaling component to fine-tune plant morphogenesis in response to environmental conditions.

  3. Direct power control of DFIG based on discrete space vector modulation

    Energy Technology Data Exchange (ETDEWEB)

    Verij Kazemi, Mohammad; Sadeghi Yazdankhah, Ahmad; Madadi Kojabadi, Hossein [Electrical Engineering Department, Sahand University of Technology, Tabriz (Iran)

    2010-05-15

    This paper presents a new direct power control (DPC) strategy for a double fed induction generator (DFIG) based wind energy generation system. Switching vectors for rotor side converter were selected from the optimal switching table using the estimated stator flux position and the errors of the active and reactive power. A few number of voltage vectors may cause undesired power and stator current ripple. In this paper the increased number of voltage vectors with application of the Discrete Space Vector Modulation (DSVM) will be presented. Then a new switching table in supersynchronous and subsynchronous frames will be proposed. Simulation results of a 2 MW DFIG system demonstrate the effectiveness and robustness of the proposed control strategy during variations of active and reactive power, machine parameters, and wind speed. (author)

  4. Safety Evalution of Cryptography Modules within Safety Related Control Systems for Railway Applications

    Directory of Open Access Journals (Sweden)

    Maria Franekova

    2011-01-01

    Full Text Available The paper deals with the problem of safety evaluation of cryptographic modules used within safety-related control system for applications with increasing safety integrity level. The requirements to cryptographic techniques in safety-related communication for railway application are describe. The mainly part is oriented to description of mathematical apparatus for an error probability of cryptography code with a safety code, used in an additional safety communication layer. The practical results are related with the quantitative evaluation of an average error probability of code word for Euroradio protocol recommended for communication in European Train Control System.

  5. Simple and controlled single electron transistor based on doping modulation in silicon nanowires

    Science.gov (United States)

    Hofheinz, M.; Jehl, X.; Sanquer, M.; Molas, G.; Vinet, M.; Deleonibus, S.

    2006-10-01

    A simple and highly reproducible single electron transistor (SET) has been fabricated using gated silicon nanowires. The structure is a metal-oxide-semiconductor field-effect transistor made on silicon-on-insulator thin films. The channel of the transistor is the Coulomb island at low temperature. Two silicon nitride spacers deposited on each side of the gate create a modulation of doping along the nanowire that creates tunnel barriers. Such barriers are fixed and controlled, like in metallic SETs. The period of the Coulomb oscillations is set by the gate capacitance of the transistor and therefore controlled by lithography. The source and drain capacitances have also been characterized. This design could be used to build more complex SET devices.

  6. A novel oscillation control for MEMS vibratory gyroscopes using a modified electromechanical amplitude modulation technique

    Science.gov (United States)

    Ma, Wei; Lin, Yiyu; Liu, Siqi; Zheng, Xudong; Jin, Zhonghe

    2017-02-01

    This paper reports a novel oscillation control algorithm for MEMS vibratory gyroscopes using a modified electromechanical amplitude modulation (MEAM) technique, which enhances the robustness against the frequency variation of the driving mode, compared to the conventional EAM (CEAM) scheme. In this approach, the carrier voltage exerted on the proof mass is frequency-modulated by the drive resonant frequency. Accordingly, the pick-up signal from the interface circuit involves a constant-frequency component that contains the amplitude and phase information of the vibration displacement. In other words, this informational detection signal is independent of the mechanical resonant frequency, which varies due to different batches, imprecise micro-fabrication and changing environmental temperature. In this paper, the automatic gain control loop together with the phase-locked loop are simultaneously analyzed using the averaging method and Routh-Hurwitz criterion, deriving the stability condition and the parameter optimization rules of the transient response. Then, a simulation model based on the real system is set up to evaluate the control algorithm. Further, the proposed MEAM method is tested using a field-programmable-gate-array based digital platform on a capacitive vibratory gyroscope. By optimizing the control parameters, the transient response of the drive amplitude reveals a settling time of 45.2 ms without overshoot, according well with the theoretical prediction and simulation results. The first measurement results show that the amplitude variance of the drive displacement is 12 ppm in an hour while the phase standard deviation is as low as 0.0004°. The mode-split gyroscope operating under atmospheric pressure demonstrates an outstanding performance. By virtue of the proposed MEAM method, the bias instability and angle random walk are measured to be 0.9° h-1 (improved by 2.4 times compared to the CEAM method) and 0.068° (√h)-1 (improved by 1.4 times

  7. Designing Diameter-Modulated Heterostructure Nanowires of PbTe/Te by Controlled Dewetting.

    Science.gov (United States)

    Kumar, Abinash; Kundu, Subhajit; Samantaray, Debadarshini; Kundu, Paromita; Zanaga, Daniele; Bals, Sara; Ravishankar, N

    2017-12-13

    Heterostructures consisting of semiconductors with controlled morphology and interfaces find applications in many fields. A range of axial, radial, and diameter-modulated nanostructures have been synthesized primarily using vapor phase methods. Here, we present a simple wet chemical routine to synthesize heterostructures of PbTe/Te using Te nanowires as templates. A morphology evolution study for the formation of these heterostructures has been performed. On the basis of these control experiments, a pathway for the formation of these nanostructures is proposed. Reduction of a Pb precursor to Pb on Te nanowire templates followed by interdiffusion of Pb/Te leads to the formation of a thin shell of PbTe on the Te wires. Controlled dewetting of the thin shell leads to the formation of cube-shaped PbTe that is periodically arranged on the Te wires. Using control experiments, we show that different reactions parameters like rate of addition of the reducing agent, concentration of Pb precursor and thickness of initial Te nanowire play a critical role in controlling the spacing between the PbTe cubes on the Te wires. Using simple surface energy arguments, we propose a mechanism for the formation of the hybrid. The principles presented are general and can be exploited for the synthesis of other nanoscale heterostructures.

  8. Reward-Modulated Hebbian Plasticity as Leverage for Partially Embodied Control in Compliant Robotics

    Science.gov (United States)

    Burms, Jeroen; Caluwaerts, Ken; Dambre, Joni

    2015-01-01

    In embodied computation (or morphological computation), part of the complexity of motor control is offloaded to the body dynamics. We demonstrate that a simple Hebbian-like learning rule can be used to train systems with (partial) embodiment, and can be extended outside of the scope of traditional neural networks. To this end, we apply the learning rule to optimize the connection weights of recurrent neural networks with different topologies and for various tasks. We then apply this learning rule to a simulated compliant tensegrity robot by optimizing static feedback controllers that directly exploit the dynamics of the robot body. This leads to partially embodied controllers, i.e., hybrid controllers that naturally integrate the computations that are performed by the robot body into a neural network architecture. Our results demonstrate the universal applicability of reward-modulated Hebbian learning. Furthermore, they demonstrate the robustness of systems trained with the learning rule. This study strengthens our belief that compliant robots should or can be seen as computational units, instead of dumb hardware that needs a complex controller. This link between compliant robotics and neural networks is also the main reason for our search for simple universal learning rules for both neural networks and robotics. PMID:26347645

  9. Reward-Modulated Hebbian Plasticity as Leverage for Partially Embodied Control in Compliant Robotics.

    Science.gov (United States)

    Burms, Jeroen; Caluwaerts, Ken; Dambre, Joni

    2015-01-01

    In embodied computation (or morphological computation), part of the complexity of motor control is offloaded to the body dynamics. We demonstrate that a simple Hebbian-like learning rule can be used to train systems with (partial) embodiment, and can be extended outside of the scope of traditional neural networks. To this end, we apply the learning rule to optimize the connection weights of recurrent neural networks with different topologies and for various tasks. We then apply this learning rule to a simulated compliant tensegrity robot by optimizing static feedback controllers that directly exploit the dynamics of the robot body. This leads to partially embodied controllers, i.e., hybrid controllers that naturally integrate the computations that are performed by the robot body into a neural network architecture. Our results demonstrate the universal applicability of reward-modulated Hebbian learning. Furthermore, they demonstrate the robustness of systems trained with the learning rule. This study strengthens our belief that compliant robots should or can be seen as computational units, instead of dumb hardware that needs a complex controller. This link between compliant robotics and neural networks is also the main reason for our search for simple universal learning rules for both neural networks and robotics.

  10. Reward modulated Hebbian plasticity as leverage for partially embodied control in compliant robotics

    Directory of Open Access Journals (Sweden)

    Jeroen eBurms

    2015-08-01

    Full Text Available In embodied computation (or morphological computation, part of the complexity of motor control is offloaded to the body dynamics. We demonstrate that a simple Hebbian-like learning rule can be used to train systems with (partial embodiment, and can be extended outside of the scope of traditional neural networks. To this end, we apply the learning rule to optimise the connection weights of recurrent neural networks with different topologies and for various tasks. We then apply this learning rule to a simulated compliant tensegrity robot by optimizing static feedback controllers that directly exploit the dynamics of the robot body. This leads to partially embodied controllers, i.e., hybrid controllers that naturally integrate the computations that are performed by the robot body into a neural network architecture. Our results demonstrate the universal applicability of reward-modulated Hebbian learning. Furthermore, they demonstrate the robustness of systems trained with the learning rule. This study strengthens our belief that compliant robots should or can be seen as computational units, instead of dumb hardware that needs a complex controller. This link between compliant robotics and neural networks is also the main reason for our search for simple universal learning rules for both neural networks and robotics.

  11. A voltage control method for an active capacitive DC-link module with series-connected circuit

    DEFF Research Database (Denmark)

    Wang, Haoran; Wang, Huai; Blaabjerg, Frede

    2017-01-01

    capacitive DC-link module is proposed. Current sensor at the DC-link will be cancel from the circuit. The controller of the series-connected circuit requires internal voltage signals of the DC-link module only, making it possible to be fully independent without any additional connection to the main circuit......Many efforts have been made to improve the performance of power electronic systems with active capacitive DC-link module in terms of power density as well as reliability. One of the attractive solution is an active capacitive DC-link with the series-connected circuit because of handling small...

  12. K- nuclear states: Binding energies and widths

    Science.gov (United States)

    Hrtánková, J.; Mareš, J.

    2017-07-01

    K- optical potentials relevant to calculations of K- nuclear quasibound states were developed within several chiral meson-baryon coupled-channels interaction models. The applied models yield quite different K- binding energies and widths. Then the K- multinucleon interactions were incorporated by a phenomenological optical potential fitted recently to kaonic atom data. Though the applied K- interaction models differ significantly in the K-N subthreshold region, our self-consistent calculations of kaonic nuclei across the periodic table lead to conclusions valid quite generally. Due to K- multinucleon absorption in the nuclear medium, the calculated widths of K- nuclear states are sizable, ΓK-≥90 MeV, and exceed substantially their binding energies in all considered nuclei.

  13. From bidirectional rectifier to polarity-controllable transistor in black phosphorus by dual gate modulation

    Science.gov (United States)

    Wang, Guocai; Bao, Lihong; Ma, Ruisong; Pei, Tengfei; Zhang, Yu-Yang; Wu, Liangmei; Zhou, Zhang; Yang, Haifang; Li, Junjie; Gu, Changzhi; Du, Shixuan; Pantelides, Sokrates T.; Gao, Hong-Jun

    2017-06-01

    In complementary metal oxide semiconductor (CMOS) technology, well-defined unipolar transport in field-effect transistors (FETs) is a basic requirement for logic operations, which can be realized by controllable doping of the semiconductor with electrons (n-type) or holes (p-type). However, recent demonstration of polarity controllable transistors in 2D semiconductors provides a flexible way in circuit design with increased circuit integration density. Here we demonstrate the conversion of a bidirectional rectifier to a polarity-controllable transistor in black phosphorus (BP) by dual gate modulation. Electrical characterization of the BP bidirectional rectifier reveals a current rectification of ~35 at room temperature that increases to ~350 upon lowering the temperature to 110 K. Employing cross-linked PMMA as a top gate and combining it together with the global back gate of the SiO2 substrate, well-defined unipolar transport (n- or p-type) in BP could get accessed. This successful realization of polarity-controllable transistor in BP provides an alternative design for development of BP logic electronics.

  14. Catechol-O-methyltransferase (COMT) polymorphisms modulate working memory in individuals with schizophrenia and healthy controls.

    Science.gov (United States)

    Matsuzaka, Camila T; Christofolini, Denise; Ota, Vanessa K; Gadelha, Ary; Berberian, Arthur A; Noto, Cristiano; Mazzotti, Diego R; Spindola, Leticia M; Moretti, Patricia N; Smith, Marilia A C; Melaragno, Maria I; Belangero, Sintia I; Bressan, Rodrigo A

    2017-01-01

    Cognitive impairment is a core feature of schizophrenia, related to dopaminergic dysfunction in the prefrontal cortex (PFC). It is hypothesized that functional single nucleotide polymorphism (SNP) rs4680 of the catechol-O-methyltransferase (COMT) gene could mediate the relationship between cognition and dopamine activity in the PFC. Other COMT SNPs could also play a role. We evaluated the role of three COMT SNPs (rs737865, rs165599, and rs4680) in schizophrenia and their impact on three working memory tasks. For genetic association analyses, 212 individuals with schizophrenia and 257 healthy controls (HCs) were selected. The Visual Working Memory (VWM) Task, Keep Track Task, and Letter Memory Task were administered to 133 schizophrenics and 93 HCs. We found a significant association of rs737865, with the GG genotype exerting a protective effect and the GA haplotype (rs4680/rs165599) exerting a risk effect for schizophrenia. COMT rs4680 AA carriers and rs737865 AA carriers scored lowest on the Keep Track Task. When the genotype*group interaction effect was evaluated, rs165599 exerted opposite effects for VWM and Keep Track task performance in patients and controls, with AA carriers scoring lowest on both tests among controls, but highest among patients. These data support the hypothesis that COMT polymorphisms may be associated with schizophrenia and modulate cognition in patients and controls.

  15. Catechol-O-methyltransferase (COMT polymorphisms modulate working memory in individuals with schizophrenia and healthy controls

    Directory of Open Access Journals (Sweden)

    Camila T. Matsuzaka

    2017-03-01

    Full Text Available Objective: Cognitive impairment is a core feature of schizophrenia, related to dopaminergic dysfunction in the prefrontal cortex (PFC. It is hypothesized that functional single nucleotide polymorphism (SNP rs4680 of the catechol-O-methyltransferase (COMT gene could mediate the relationship between cognition and dopamine activity in the PFC. Other COMT SNPs could also play a role. Methods: We evaluated the role of three COMT SNPs (rs737865, rs165599, and rs4680 in schizophrenia and their impact on three working memory tasks. For genetic association analyses, 212 individuals with schizophrenia and 257 healthy controls (HCs were selected. The Visual Working Memory (VWM Task, Keep Track Task, and Letter Memory Task were administered to 133 schizophrenics and 93 HCs. Results: We found a significant association of rs737865, with the GG genotype exerting a protective effect and the GA haplotype (rs4680/rs165599 exerting a risk effect for schizophrenia. COMT rs4680 AA carriers and rs737865 AA carriers scored lowest on the Keep Track Task. When the genotype*group interaction effect was evaluated, rs165599 exerted opposite effects for VWM and Keep Track task performance in patients and controls, with AA carriers scoring lowest on both tests among controls, but highest among patients. Conclusion: These data support the hypothesis that COMT polymorphisms may be associated with schizophrenia and modulate cognition in patients and controls.

  16. Ghrelin potentiates cardiac reactivity to stress by modulating sympathetic control and beta-adrenergic response.

    Science.gov (United States)

    Camargo-Silva, Gabriel; Turones, Larissa Córdova; da Cruz, Kellen Rosa; Gomes, Karina Pereira; Mendonça, Michelle Mendanha; Nunes, Allancer; de Jesus, Itamar Guedes; Colugnati, Diego Basile; Pansani, Aline Priscila; Pobbe, Roger Luis Henschel; Santos, Robson; Fontes, Marco Antônio Peliky; Guatimosim, Silvia; de Castro, Carlos Henrique; Ianzer, Danielle; Ferreira, Reginaldo Nassar; Xavier, Carlos Henrique

    2018-03-01

    Prior evidence indicates that ghrelin is involved in the integration of cardiovascular functions and behavioral responses. Ghrelin actions are mediated by the growth hormone secretagogue receptor subtype 1a (GHS-R1a), which is expressed in peripheral tissues and central areas involved in the control of cardiovascular responses to stress. In the present study, we assessed the role of ghrelin - GHS-R1a axis in the cardiovascular reactivity to acute emotional stress in rats. Ghrelin potentiated the tachycardia evoked by restraint and air jet stresses, which was reverted by GHS-R1a blockade. Evaluation of the autonomic balance revealed that the sympathetic branch modulates the ghrelin-evoked positive chronotropy. In isolated hearts, the perfusion with ghrelin potentiated the contractile responses caused by stimulation of the beta-adrenergic receptor, without altering the amplitude of the responses evoked by acetylcholine. Experiments in isolated cardiomyocytes revealed that ghrelin amplified the increases in calcium transient changes evoked by isoproterenol. Taken together, our results indicate that the Ghrelin-GHS-R1a axis potentiates the magnitude of stress-evoked tachycardia by modulating the autonomic nervous system and peripheral mechanisms, strongly relying on the activation of cardiac calcium transient and beta-adrenergic receptors. Copyright © 2018 Elsevier Inc. All rights reserved.

  17. Continuum RPA calculation of escape widths

    Energy Technology Data Exchange (ETDEWEB)

    Vertse, T. (Inst. of Nuclear Research, Hungarian Academy of Sciences, Debrecen (Hungary)); Curutchet, P.; Liotta, R.J. (Manne Siegbahn Inst. of Physics, Stockholm (Sweden)); Bang, J. (Niels Bohr Inst., Copenhagen (Denmark)); Giai, N. van (Inst. de Physique Nucleaire, 91 - Orsay (France))

    1991-07-25

    Particle-hole partial decay widths are calculated within the continuum RPA exactly, i.e. without any further approximation, in a square well plus Coulomb potential and using a separable residual interaction. The results are compared with the ones obtained by making pole expansions of the single-particle Green functions (Berggren and Mittag-Leffler). It is found that the Berggren and Mittag-Leffler expansions give results in good agreement with the 'exact' ones. (orig.).

  18. Dynamics of niche width and resource partitioning.

    OpenAIRE

    Dobrev, S.; Kim, T-Y; Hannan, M.T.

    2001-01-01

    This article examines the effects of crowding in a market center on rates of change in organizational niche width and on organizational mortality. It proposes that, although firms with wide niches benefit from risk spreading and economies of scale, they are simultaneously exposed to intense competition. An analysis of organizational dynamics in automobile manufacturing firms in France, Germany, and Great Britain shows that competitive pressure not only increases the hazard of disbanding but a...

  19. Testing Computability by Width Two OBDDs

    Science.gov (United States)

    Ron, Dana; Tsur, Gilad

    Property testing is concerned with deciding whether an object (e.g. a graph or a function) has a certain property or is “far” (for some definition of far) from every object with that property. In this paper we give lower and upper bounds for testing functions for the property of being computable by a read-once width-2 Ordered Binary Decision Diagram (OBDD), also known as a branching program, where the order of the variables is known. Width-2 OBDDs generalize two classes of functions that have been studied in the context of property testing - linear functions (over GF(2)) and monomials. In both these cases membership can be tested in time that is linear in 1/ɛ. Interestingly, unlike either of these classes, in which the query complexity of the testing algorithm does not depend on the number, n, of variables in the tested function, we show that (one-sided error) testing for computability by a width-2 OBDD requires Ω(log(n)) queries, and give an algorithm (with one-sided error) that tests for this property and performs tilde{O}(log(n)/ɛ) queries.

  20. Interface Control Document for the EMPACT Module that Estimates Electric Power Transmission System Response to EMP-Caused Damage

    Energy Technology Data Exchange (ETDEWEB)

    Werley, Kenneth Alan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mccown, Andrew William [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)ory

    2016-06-26

    The EPREP code is designed to evaluate the effects of an Electro-Magnetic Pulse (EMP) on the electric power transmission system. The EPREP code embodies an umbrella framework that allows a user to set up analysis conditions and to examine analysis results. The code links to three major physics/engineering modules. The first module describes the EM wave in space and time. The second module evaluates the damage caused by the wave on specific electric power (EP) transmission system components. The third module evaluates the consequence of the damaged network on its (reduced) ability to provide electric power to meet demand. This third module is the focus of the present paper. The EMPACT code serves as the third module. The EMPACT name denotes EMP effects on Alternating Current Transmission systems. The EMPACT algorithms compute electric power transmission network flow solutions under severely damaged network conditions. Initial solutions are often characterized by unacceptible network conditions including line overloads and bad voltages. The EMPACT code contains algorithms to adjust optimally network parameters to eliminate network problems while minimizing outages. System adjustments include automatically adjusting control equipment (generator V control, variable transformers, and variable shunts), as well as non-automatic control of generator power settings and minimal load shedding. The goal is to evaluate the minimal loss of customer load under equilibrium (steady-state) conditions during peak demand.

  1. Stark widths regularities within spectral series of sodium isoelectronic sequence

    Science.gov (United States)

    Trklja, Nora; Tapalaga, Irinel; Dojčinović, Ivan P.; Purić, Jagoš

    2018-02-01

    Stark widths within spectral series of sodium isoelectronic sequence have been studied. This is a unique approach that includes both neutrals and ions. Two levels of problem are considered: if the required atomic parameters are known, Stark widths can be calculated by some of the known methods (in present paper modified semiempirical formula has been used), but if there is a lack of parameters, regularities enable determination of Stark broadening data. In the framework of regularity research, Stark broadening dependence on environmental conditions and certain atomic parameters has been investigated. The aim of this work is to give a simple model, with minimum of required parameters, which can be used for calculation of Stark broadening data for any chosen transitions within sodium like emitters. Obtained relations were used for predictions of Stark widths for transitions that have not been measured or calculated yet. This system enables fast data processing by using of proposed theoretical model and it provides quality control and verification of obtained results.

  2. Synchronised Voltage Space Vector Modulation for Three-level Inverters with Common-mode Voltage Elimination

    DEFF Research Database (Denmark)

    Oleschuk, Valentin; Blaabjerg, Frede

    2002-01-01

    A novel method of direct synchronous pulse-width modulation (PWM) is disseminated to three-level voltage source inverters with control algorithms with elimination of the common-mode voltages in three-phase drive systems with PWM. It provides smooth pulses-ratio changing and a quarter-wave symmetry...

  3. Three-Level Inverters with Common-Mode Voltage Cancellation Based on Synchronous Pulsewidth Modulation

    DEFF Research Database (Denmark)

    Oleschuk, Valentin; Blaabjerg, Frede

    2002-01-01

    A novel method of direct synchronous pulse-width modulation (PWM) is disseminated to three-level voltage source inverters with control algorithms with elimination of the common-mode voltages in three-phase drive systems with PWM. It provides smooth pulses-ratio changing and a quarter-wave symmetry...

  4. Control of lignin solubility and particle formation modulates its antioxidant efficiency in lipid medium

    DEFF Research Database (Denmark)

    Barsberg, Søren Talbro; Thygesen, Lisbeth Garbrecht; Sanadi, Anand Ramesh

    2014-01-01

    Lignin is an abundant plant polymer usually regarded as waste material. In the present work, antioxidant properties of lignin preparations with differing lipid solubility were studied using biodiesel as a convenient lipid test substrate. In place of formerly used assays, we used attenuated total...... reflectance (ATR) FT-IR spectroscopy to follow in situ biodiesel autoxidation on a heated ATR crystal as a function of time. The study demonstrates that a complex balance between intrinsic (chemical) efficiency, solubility, and particle formation controls the antioxidant efficiency of differently prepared...... lignin fractions. It was found that solubility and particle formation of lignin preparations strongly modulate its antioxidant efficiency and that these properties might depend on the presence of lipid components within the original lignin source....

  5. Identification and Characterization of GAL-021 as a Novel Breathing Control Modulator.

    Science.gov (United States)

    Golder, Francis J; Dax, Scott; Baby, Santhosh M; Gruber, Ryan; Hoshi, Toshinori; Ideo, Courtney; Kennedy, Andrew; Peng, Sean; Puskovic, Veljko; Ritchie, David; Woodward, Richard; Wardle, Robert L; Van Scott, Michael R; Mannion, James C; MacIntyre, D Euan

    2015-11-01

    The authors describe the preclinical pharmacological properties of GAL-021, a novel peripheral chemoreceptor modulator. The ventilatory effects of GAL-021 were characterized using tracheal pneumotachometry (n = 4 to 6), plethysmography (n = 5 to 6), arterial blood gas analyses (n = 6 to 11), and nasal capnography (n = 3 to 4) in naive animals and those subjected to morphine-induced respiratory depression. Morphine analgesia in rats was evaluated by tail-flick test (n = 6). Carotid body involvement in GAL-021 ventilatory effects was assessed by comparing responses in intact and carotid sinus nerve-transected rats. Hemodynamic effects of GAL-021 were evaluated in urethane-anesthetized rats (n = 7). The pharmacological profile of GAL-021 in vitro was investigated using radioligand binding, enzyme inhibition, and cellular electrophysiology assays. GAL-021 given intravenously stimulated ventilation and/or attenuated opiate-induced respiratory depression in rats, mice, and nonhuman primates, without decreasing morphine analgesia in rats. GAL-021 did not alter mean arterial pressure but produced a modest increase in heart rate. Ventilatory stimulation in rats was attenuated by carotid sinus nerve transection. GAL-021 inhibited KCa1.1 in GH3 cells, and the evoked ventilatory stimulation was attenuated in Slo1 mice lacking the pore-forming α-subunit of the KCa1.1 channel. GAL-021 behaved as a breathing control modulator in rodents and nonhuman primates and diminished opioid-induced respiratory depression without compromising opioid analgesia. It acted predominantly at the carotid body, in part by inhibiting KCa1.1 channels. Its preclinical profile qualified the compound to enter clinical trials to assess effects on breathing control disorders such as drug (opioid)-induced respiratory depression and sleep apnea.

  6. Autonomic Modulation in Duchenne Muscular Dystrophy during a Computer Task: A Prospective Control Trial.

    Directory of Open Access Journals (Sweden)

    Mayra Priscila Boscolo Alvarez

    Full Text Available Duchenne Muscular Dystrophy (DMD is characterized by progressive muscle weakness that can lead to disability. Owing to functional difficulties faced by individuals with DMD, the use of assistive technology is essential to provide or facilitate functional abilities. In DMD, cardiac autonomic dysfunction has been reported in addition to musculoskeletal impairment. Consequently, the objective was to investigate acute cardiac autonomic responses, by Heart Rate Variability (HRV, during computer tasks in subjects with DMD.HRV was assessed by linear and nonlinear methods, using the heart rate monitor Polar RS800CX chest strap Electrocardiographic measuring device. Then, 45 subjects were included in the group with DMD and 45 in the healthy Typical Development (TD control group. They were assessed for twenty minutes at rest sitting, and five minutes after undergoing a task on the computer.Individuals with DMD had a statistically significant lower parasympathetic cardiac modulation at rest when compared to the control group, which further declined when undergoing the tasks on the computer.DMD patients presented decreased HRV and exhibited greater intensity of cardiac autonomic responses during computer tasks characterized by vagal withdrawal when compared to the healthy TD control subjects.

  7. Direct modulation of T-box riboswitch-controlled transcription by protein synthesis inhibitors.

    Science.gov (United States)

    Stamatopoulou, Vassiliki; Apostolidi, Maria; Li, Shuang; Lamprinou, Katerina; Papakyriakou, Athanasios; Zhang, Jinwei; Stathopoulos, Constantinos

    2017-09-29

    Recently, it was discovered that exposure to mainstream antibiotics activate numerous bacterial riboregulators that control antibiotic resistance genes including metabolite-binding riboswitches and other transcription attenuators. However, the effects of commonly used antibiotics, many of which exhibit RNA-binding properties, on the widespread T-box riboswitches, remain unknown. In Staphylococcus aureus, a species-specific glyS T-box controls the supply of glycine for both ribosomal translation and cell wall synthesis, making it a promising target for next-generation antimicrobials. Here, we report that specific protein synthesis inhibitors could either significantly increase T-box-mediated transcription antitermination, while other compounds could suppress it, both in vitro and in vivo. In-line probing of the full-length T-box combined with molecular modelling and docking analyses suggest that the antibiotics that promote transcription antitermination stabilize the T-box:tRNA complex through binding specific positions on stem I and the Staphylococcal-specific stem Sa. By contrast, the antibiotics that attenuate T-box transcription bind to other positions on stem I and do not interact with stem Sa. Taken together, our results reveal that the transcription of essential genes controlled by T-box riboswitches can be directly modulated by commonly used protein synthesis inhibitors. These findings accentuate the regulatory complexities of bacterial response to antimicrobials that involve multiple riboregulators. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

  8. Thermal Control System Development to Support the Crew Exploration Vehicle and Lunar Surface Access Module

    Science.gov (United States)

    Anderson, Molly; Westheimer, David

    2006-01-01

    All space vehicles or habitats require thermal management to maintain a safe and operational environment for both crew and hardware. Active Thermal Control Systems (ATCS) perform the functions of acquiring heat from both crew and hardware within a vehicle, transporting that heat throughout the vehicle, and finally rejecting that energy into space. Almost all of the energy used in a space vehicle eventually turns into heat, which must be rejected in order to maintain an energy balance and temperature control of the vehicle. For crewed vehicles, Active Thermal Control Systems are pumped fluid loops that are made up of components designed to perform these functions. NASA has recently evaluated all of the agency s technology development work and identified key areas that must be addressed to aid in the successful development of a Crew Exploration Vehicle (CEV) and a Lunar Surface Access Module (LSAM). The technologies that have been selected and are currently under development include: fluids that enable single loop ATCS architectures, a gravity insensitive vapor compression cycle heat pump, a sublimator with reduced sensitivity to feedwater contamination, an evaporative heat sink that can operate in multiple ambient pressure environments, a compact spray evaporator, and lightweight radiators that take advantage of carbon composites and advanced optical coatings.

  9. Effects of hand posture on preparatory control processes and sensory modulations in tactile-spatial attention.

    Science.gov (United States)

    Eimer, Martin; Forster, Bettina; Fieger, Anne; Harbich, Stefanie

    2004-03-01

    Event-related brain potentials (ERPs) were measured to investigate spatial coordinate systems involved in the control of preparatory tactile-spatial orienting, and in subsequent attentional modulations of somatosensory processing. On each trial, a visual precue directed attention to the left or right hand, where infrequent tactile targets had to be detected. Hands were positioned either close together or wide apart. ERPs were recorded in the cue-target interval and in response to attended and unattended tactile non-targets. A frontal anterior directing attention negativity (ADAN) and a posterior late directing attention positivity (LDAP) were elicited in the cue-target interval contralateral to the direction of an attentional shift. The ADAN was unaffected by hand posture, but the LDAP was attenuated when hands were close together. N140 amplitudes were enhanced in response to tactile stimuli presented to the attended hand, and this effect was more pronounced when hands were wide apart. ADAN and LDAP are linked to separable anterior and posterior attentional control systems, which use coordinate systems based on somatotopic and external space, respectively. Effects of spatial attention on somatosensory stimulus processing are affected by variations in body posture. Our results demonstrate that representations of body locations in external space play a central role in the control of tactile attention.

  10. Effects of increased homeostatic sleep pressure on postural control and their modulation by attentional resources.

    Science.gov (United States)

    Robillard, Rébecca; Prince, François; Boissonneault, Michèle; Filipini, Daniel; Carrier, Julie

    2011-09-01

    This study aimed to determine how increased sleep pressure interferes with postural control according to the availability of attentional resources and visual input. Thirteen healthy young adults performed a psychomotor vigilance task and postural tasks after a night of sleep and after 25 h of sleep deprivation. Primary outcome variables were calculated from the center of pressure (CoP) displacement measured by two force plates in various cognitive load and visual state conditions. Sleep deprivation increased CoP anterior-posterior range in the no cognitive load condition and decreased CoP mediolateral range and velocity in the high cognitive load conditions. Sleep deprivation effects on the mediolateral range in the eyes open high cognitive load condition were significantly correlated with its effects on the psychomotor vigilance task. Sleep deprivation destabilizes postural control when attentional and sensory resources are not challenged. In high cognitive load condition, sleep loss induces a general freezing effect that seems to be modulated by the degree of impairment in psychomotor speed. This study demonstrates that sleep pressure has a destabilizing effect on postural control independently of circadian factors, therefore suggesting that sleep debt may be a significant risk factor for falls. Copyright © 2011 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  11. Disease-Control Rates Following Intensity-Modulated Radiation Therapy for Small Primary Oropharyngeal Carcinoma

    Science.gov (United States)

    Garden, Adam S.; Morrison, William H.; Wong, Pei-Fong; Tung, Sam S.; Rosenthal, David I.; Dong, Lei; Mason, Brian; Perkins, George H.; Ang, K. Kian

    2014-01-01

    Background The purpose of this study was to assess the ability of intensity-modulated radiation therapy (IMRT) to achieve favorable disease-control rates while minimizing parotid gland doses in patients treated for small primary tumors of the oropharynx. Methods We retrospectively identified all patients who received IMRT as treatment for a small (therapy; in 4 patients, the tube remained in place for more than 6 months following completion of IMRT. The median follow-up was 45 months. The 2-year actuarial local-regional control, recurrence-free, and overall survival rates were 94%, 88%, and 94%, respectively. Conclusions These preliminary data suggest that treatment with IMRT results in favorable local-regional control of small primary oropharynx tumors. IMRT did not appear to have a more favorable acute toxicity profile in this group with respect to the use of a feeding tube; however, the mean dose of radiation delivered to the parotid gland by IMRT was decreased, as 95% of patients had a mean dose of < 30 Gy to at least one gland. PMID:17141972

  12. Control Solutions for High Performance in ITER with Test Blanket Modules

    Science.gov (United States)

    Lanctot, M. J.; Degrassie, J. S.; La Haye, R. J.; Paz-Soldan, C.; Strait, E. J.; Buttery, R. J.; Snipes, J. A.; Reimerdes, H.; Logan, N. C.; Park, J.-K.; Solomon, W. M.; Grierson, B.; Hanson, J. M.

    2014-10-01

    DIII-D experiments indicate applied n = 1 fields can be used in high performance plasma regimes to reduce to a tolerable level the impact of the Test Blanket Modules (TBMs) error field (EF) on energy and particle confinement. Active coils, designed to mock-up the magnetic EF from two TBMs in one ITER equatorial port, were used to mimic the magnetization from the reduced-activation ferritic martensitic steel used in present TBM designs. The optimal correction fields, identified by maximizing the plasma toroidal angular momentum, reduced the impact of the TBM EF on energy, particle, and momentum confinement at βN = 2 . 9 by 60%, a factor of 2 improvement over previous results at βN = 1 . 8 . This improved performance of n = 1 control fields at high beta is consistent with the hypothesis that the strong beta dependence of TBM EF effects observed in previous campaigns is due mainly to amplification of the n = 1 component of the TBM EF. Similar performance was obtained with either internal or external n = 1 error field control coils. The results suggest that the impact of the TBM related EFs on high beta operation can be controlled with the external correction coils in ITER. Work supported by the US DOE under DE-FC02-04ER54698, DE-AC02-09CH11466 and DE-FG02-04ER54761.

  13. Motor planning modulates sensory-motor control of collision avoidance behavior in the bullfrog, Rana catesbeiana

    Directory of Open Access Journals (Sweden)

    Hideki Nakagawa

    2012-08-01

    In this study, we examined the collision avoidance behavior of the frog, Rana catesbeiana to an approaching object in the upper visual field. The angular velocity of the frog's escape turn showed a significant positive correlation with the turn angle (r2 = 0.5741, P0.05. Thus, the frog was not able to control the velocity of the large escape turns accurately and did not complete the behavior within a constant time. In the latter case, there was a small but significant positive correlation between the threshold angular size and the angular velocity (r2 = 0.1459, P<0.05. This suggests that the threshold is controlled to compensate for the insufficient escape velocity achieved during large turn angles, and could explain a significant negative correlation between the turn angle and the threshold angular size (r2 = 0.1145, P<0.05. Thus, it is likely that the threshold angular size is also controlled by the turn angle and is modulated by motor planning.

  14. Controller for a High-Power, Brushless dc Motor

    Science.gov (United States)

    Fleming, David J.; Makdad, Terence A.

    1987-01-01

    Driving and braking torques controllable. Control circuit operates 7-kW, 45-lb-ft (61-N-m), three-phase, brushless dc motor in both motor and generator modes. In motor modes, energy from power source is pulse-width modulated to motor through modified "H-bridge" circuit, in generator mode, energy from motor is pulse-width modulated into bank of load resistors to provide variable braking torques. Circuit provides high-resolution torque control in both directions over wide range of speeds and torques. Tested successfully at bus voltages up to 200 Vdc and currents up to 45 A.

  15. Unravelling the role of quantum interference in the weak-field laser phase modulation control of photofragment distributions.

    Science.gov (United States)

    García-Vela, Alberto; Henriksen, Niels E

    2016-02-14

    The role played by quantum interference in the laser phase modulation coherent control of photofragment distributions in the weak-field regime is investigated in detail in this work. The specific application involves realistic wave packet calculations of the transient vibrational populations of the Br2(B,vf) fragment produced upon predissociation of the Ne-Br2(B) complex, which is excited to a superposition of overlapping resonance states using different fixed bandwidth pulses where the linear chirps are varied. The postpulse transient phase modulation effects observed on fragment populations for a long time window are explained in terms of the mechanism of interference between overlapping resonances. A detailed description of how the interference mechanism affects the magnitude and the time window of the phase control effects is also provided. In the light of the results, the conditions to maximize phase modulation control on fragment distributions are discussed.

  16. Thermal Equilibrium Dynamic Control Based on DPWM Dual-Mode Modulation of High Power NPC Three-Level Inverter

    Directory of Open Access Journals (Sweden)

    Shi-Zhou Xu

    2016-01-01

    Full Text Available In some special applications of NPC three-level inverters, such as mine hoist, there exist special conditions of overloading during the whole hoisting process and large overload in starting stage, during which the power-loss calculation of power devices and thermal control are important factors affecting the thermal stability of inverters. The principles of SVPWM and DPWM were described in this paper firstly, based on which the dynamic power losses of the two modulations of hoist in single period were calculated. Secondly, a thermal equilibrium dynamic control based on DPMW dual-mode modulation was proposed, which can switch the modulation dynamically according to the change of dynamic power loss to realize dynamic control of power loss and thermal equilibrium of inverter. Finally, simulation and experiment prove the effectiveness of the proposed strategy.

  17. Cognitive Control Modulates Effects of Episodic Simulation on Delay Discounting in Aging.

    Science.gov (United States)

    Sasse, Laura K; Peters, Jan; Brassen, Stefanie

    2017-01-01

    Enhancing prospective thinking by tagging the future with specific episodic events has been shown to reduce delay discounting in young age ("tag-effect"). So far, it is unclear whether such beneficial effect extends to old adulthood. Since the general ability of future thinking and cognitive control are crucial modulators of temporal discounting in young age, potential age-related decline in these functions might impact on the effect. We focused on this issue by combining functional magnetic resonance imaging (fMRI) with an established intertemporal choice task including episodic "tags" in healthy older participants. Future thinking ability was assessed using autobiographical interviews for future event simulations and a visual search task was applied to assess participants' cognitive control ability. In contrast to previous data in young adults, the group of older participants did not benefit from tagging the future with episodic events. Older participants' cognitive control function was directly associated with discounting rates in the episodic conditions: the less the older adults were able to focus their attention the less they benefited from the inclusion of episodic events. Consistent with this, imaging results revealed that: (a) subjective value (SV) signals in the hippocampus and the anterior cingulate cortex (ACC) as well as; (b) hippocampal-striatal coupling during the episodic condition were positively related to participants' control capacity. Our findings highlight the critical role of executive functioning for the simultaneous integration of episodic information with future value computation in aging. Boosting delay gratification by including episodic tags might hence be limited in older individuals with pronounced decline in distraction control.

  18. Anticipatory modulation of digit placement for grasp control is affected by Parkinson's disease.

    Directory of Open Access Journals (Sweden)

    Jamie R Lukos

    2010-02-01

    Full Text Available Successful object manipulation relies on the ability to form and retrieve sensorimotor memories of digit forces and positions used in previous object lifts. Past studies of patients affected by Parkinson's disease (PD have revealed that the basal ganglia play a crucial role in the acquisition and/or retrieval of sensorimotor memories for grasp control. Whereas it is known that PD impairs anticipatory control of digit forces during grasp, learning deficits associated with the planning of digit placement have yet to be explored. This question is motivated by recent work in healthy subjects revealing that anticipatory control of digit placement plays a crucial role for successful manipulation.We asked ten PD patients off medication and ten age-matched controls to reach, grasp and lift an object whose center of mass (CM was on the left, right or center. The only task requirement was to minimize object roll during lift. The CM remained the same across consecutive trials (blocked condition or was altered from trial to trial (random condition. We hypothesized that impairment of the basal ganglia-thalamo-cortical circuits in PD patients would reduce their ability to anticipate digit placement appropriate to the CM location. Consequently, we predicted that PD patients would exhibit similar digit placement in the blocked vs. random conditions and produce larger peak object rolls than that of control subjects. In the blocked condition, PD patients exhibited significantly weaker modulation of fingertip contact points to CM location and larger object roll than controls (p<0.05 and p<0.01, respectively. Nevertheless, both controls and PD patients minimized object roll more in the blocked than in the random condition (p<0.01.Our findings indicate that, even though PD patients may have a residual ability of anticipatory control of digit contact points and forces, they fail to implement a motor plan with the same degree of effectiveness as controls. We conclude

  19. High-frequency combustion instability control through acoustic modulation at the inlet boundary for liquid rocket engine applications

    Science.gov (United States)

    Bennewitz, John William

    This research investigation encompasses experimental tests demonstrating the control of a high-frequency combustion instability by acoustically modulating the propellant flow. A model rocket combustor burned gaseous oxygen and methane using a single-element, pentad-style injector. Flow conditions were established that spontaneously excited a 2430 Hz first longitudinal combustion oscillation at an amplitude up to p'/pc ≈ 6%. An acoustic speaker was placed at the base of the oxidizer supply to modulate the flow and alter the oscillatory behavior of the combustor. Two speaker modulation approaches were investigated: (1) Bands of white noise and (2) Pure sinusoidal tones. The first approach adjusted 500 Hz bands of white noise ranging from 0-500 Hz to 2000-2500 Hz, while the second implemented single-frequency signals with arbitrary phase swept from 500-2500 Hz. The results showed that above a modulation signal amplitude threshold, both approaches suppressed 95+% of the spontaneous combustion oscillation. By increasing the applied signal amplitude, a wider frequency range of instability suppression became present for these two acoustic modulation approaches. Complimentary to these experiments, a linear modal analysis was undertaken to investigate the effects of acoustic modulation at the inlet boundary on the longitudinal instability modes of a dump combustor. The modal analysis employed acoustically consistent matching conditions with a specific impedance boundary condition at the inlet to represent the acoustic modulation. From the modal analysis, a naturally unstable first longitudinal mode was predicted in the absence of acoustic modulation, consistent with the spontaneously excited 2430 Hz instability observed experimentally. Subsequently, a detailed investigation involving variation of the modulation signal from 0-2500 Hz and mean combustor temperature from 1248-1685 K demonstrated the unstable to stable transition of a 2300-2500 Hz first longitudinal mode. The

  20. Cascaded multi-dithering technique using PZT modulators for high control bandwidth in coherent laser beam combining

    Science.gov (United States)

    Ahn, Hee Kyung; Kong, Hong Jin

    2017-09-01

    A cascaded multi-dithering (CMD) technique using piezoelectric ceramic transducer (PZT) tubes as phase modulators is proposed as a tool for obtaining high control bandwidth in coherent laser beam combination. To prove its validity, eight coherent fiber beam elements were combined using the CMD technique with PZT tubes. As a result, residual phase error was recorded to be λ/54 at 100 Hz control bandwidth, which is comparable to that of a four laser beam combination in the previous experiment. To our knowledge, this is the first case to date of combining eight laser beam elements using PZT tubes as phase modulators and achieving such good results.

  1. Intensity modulated radiation therapy: Analysis of patient specific quality control results, experience of Rene-Gauducheau Centre; Radiotherapie conformationnelle avec modulation d'intensite: analyse des resultats des controles precliniques, experience du centre Rene-Gauducheau

    Energy Technology Data Exchange (ETDEWEB)

    Chiavassa, S.; Brunet, G.; Gaudaire, S.; Munos-Llagostera, C.; Delpon, G.; Lisbona, A. [Service de physique medicale, centre Rene-Gauducheau, CLCC Nantes Atlantique, site hospitalier Nord, boulevard Jacques-Monod, 44805 Nantes Saint-Herblain cedex (France)

    2011-07-15

    Purpose. - Systematic verifications of patient's specific intensity-modulated radiation treatments are usually performed with absolute and relative measurements. The results constitute a database which allows the identification of potential systematic errors. Material and methods. - We analyzed 1270 beams distributed in 232 treatment plans. Step-and-shoot intensity-modulated radiation treatments were performed with a Clinac (6 and 23 MV) and sliding window intensity-modulated radiation treatments with a Novalis (6 MV). Results. - The distributions obtained do not show systematic error and all the control meet specified tolerances. Conclusion. - These results allow us to reduce controls specific patients for treatments performed under identical conditions (location, optimization and segmentation parameters of treatment planning system, etc.). (authors)

  2. Design and development of a prototype 25 kV, 10 A long pulse Marx modulator for high power klystron

    Science.gov (United States)

    Acharya, Mahesh; Shrivastava, Purushottam

    2016-02-01

    Research, design, and development of high average power modulators for the proposed Indian Spallation Neutron Source are in progress at Raja Ramanna Centre for Advanced Technology. With this objective, a prototype of 25 kV, 10 A, 1 ms Marx modulator at repetition rate of 1 Hz has been designed and developed which serves as a proof of principle and technology assessment stage for further development of high repetition rate high voltage high average power modulators. Insulated Gate Bipolar Transistor (IGBT) based modules of 2.8 kV switching capability have been used as main modules. The modulator had 8.2% droop in output voltage pulse without any droop compensation circuit. A droop compensation involving 15 corrector modules has been used to reduce the droop up to 1%. We have used IGBT based 250 V switches to realize the corrector module. A microcontroller based control unit was designed and developed for triggering the main and corrector modules. With this control unit, programmable output pulse has been achieved. Electrical isolation between high voltage circuits and control circuit has been achieved by the use of fiber optic based control signal transmission. Output pulses of 1 ms pulse width, 800 ns rise time, and 5 μs fall time have been achieved. The modulator has advantages of modular design, adjustable pulse width, adjustable rise time, and fall time.

  3. Line width of Josephson flux flow oscillators

    DEFF Research Database (Denmark)

    Koshelets, V.P.; Dmitriev, P.N.; Sobolev, A.S.

    2002-01-01

    spacing of about 20 nV and extremely low differential resistance, recently observed in the IVC of the standard rectangular geometry. The obtained results have been compared with existing theories and FFO models in order to understand and possibly eliminate excess noise in the FFO. The intrinsic line width...... increases considerably at voltages above the boundary voltage because of the abrupt increase of the internal damping due to Josephson self-coupling. The influence of FFO parameters, in particular the differential resistances associated both with the bias current and with the applied magnetic field...

  4. Width Criterion For Weld-Seam-Tracking Data

    Science.gov (United States)

    Lincir, Mark R.

    1993-01-01

    Image-processing algorithm in "through-torch-vision" (T3V) system developed to guide gas/tungsten arc welding robot along weld seam modified, according to proposal, reducing incidence of inaccurate tracking of weld seam. Developmental system intended to provide closed-loop control of motion of welding robot along weld seam on basis of lines in T3V image identified by use of image-processing algorithm and assumed to coincide with edges of weld seam. Use of width criterion prevents tracking of many false pairs of lines, with consequent decrease in incidence of inaccurate tracking and increase in confidence in weld-tracking capability of robotic welding system.

  5. Modulations of the executive control network by stimulus onset asynchrony in a Stroop task.

    Science.gov (United States)

    Coderre, Emily L; van Heuven, Walter J B

    2013-07-31

    Manipulating task difficulty is a useful way of elucidating the functional recruitment of the brain's executive control network. In a Stroop task, pre-exposing the irrelevant word using varying stimulus onset asynchronies ('negative' SOAs) modulates the amount of behavioural interference and facilitation, suggesting disparate mechanisms of cognitive processing in each SOA. The current study employed a Stroop task with three SOAs (-400, -200, 0 ms), using functional magnetic resonance imaging to investigate for the first time the neural effects of SOA manipulation. Of specific interest were 1) how SOA affects the neural representation of interference and facilitation; 2) response priming effects in negative SOAs; and 3) attentional effects of blocked SOA presentation. The results revealed three regions of the executive control network that were sensitive to SOA during Stroop interference; the 0 ms SOA elicited the greatest activation of these areas but experienced relatively smaller behavioural interference, suggesting that the enhanced recruitment led to more efficient conflict processing. Response priming effects were localized to the right inferior frontal gyrus, which is consistent with the idea that this region performed response inhibition in incongruent conditions to overcome the incorrectly-primed response, as well as more general action updating and response preparation. Finally, the right superior parietal lobe was sensitive to blocked SOA presentation and was most active for the 0 ms SOA, suggesting that this region is involved in attentional control. SOA exerted both trial-specific and block-wide effects on executive processing, providing a unique paradigm for functional investigations of the cognitive control network.

  6. Modulation of a solid-state reversible fluorescent photoswitching based on a controllable photochromic pyrazolones

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hu; Guo, Jixi [Key Laboratory of Material and Technology for Clean Energy, Ministry of Education, Key Laboratory of Advanced Functional Materials, Autonomous Region, Institute of Applied Chemistry, Xinjiang University, Urumqi 830046, Xinjiang (China); Jia, Dianzeng, E-mail: jdz@xju.edu.cn [Key Laboratory of Material and Technology for Clean Energy, Ministry of Education, Key Laboratory of Advanced Functional Materials, Autonomous Region, Institute of Applied Chemistry, Xinjiang University, Urumqi 830046, Xinjiang (China); Guo, Mingxi; Le, Fuhe; Liu, Lang; Wu, Dongling [Key Laboratory of Material and Technology for Clean Energy, Ministry of Education, Key Laboratory of Advanced Functional Materials, Autonomous Region, Institute of Applied Chemistry, Xinjiang University, Urumqi 830046, Xinjiang (China); Li, Feng [State Laboratory of Surface and Interface Science and Technology, School of Materials and Chemical Engineering, Zhengzhou University of Light Industry, Zhengzhou 450002, Henan (China); University of Texas, M. D. Anderson Cancer Center, Houston, TX 77002 (United States)

    2014-08-15

    A novel solid-state reversible fluorescence photoswitching system (FPS) based on photochromism of photochromic pyrazolones has been developed by employing phosphor Sr{sub 2}P{sub 2}O{sub 7} co-doped with europium ion and chlorine ion (Sr{sub 2}P{sub 2}O{sub 7}–EC) and 1,3-diphenyl-4-(3-chlorobenzal)-5-hydroxypyrazole-4-phenylsemicarbazone (1a) as the fluorescence dye and the photochromic compound, respectively. With carefully selected components, the absorption band of the keto-form photochromic pyrazolones well overlaps with the emission peak of Sr{sub 2}P{sub 2}O{sub 7}–EC. The fluorescence emission intensity of Sr{sub 2}P{sub 2}O{sub 7}–EC is efficiently modulated by the photoisomerization of 1a with controlling the exposure time in the solid state. The fluorescence photoswitching system displayed high fluorescence quenching efficiency and remarkable fatigue resistance. It can be repeated 7 cycles without observable the changes of emission intensity. A fluorescence quenching efficiency can be achieved with a reversible colour change from white to yellow. - Graphical abstract: A novel fluorescence photoswitching system based on doping inorganic fluorescence dye into photochromic pyrazolones was constructed successfully. Its fluorescence emission could be efficiently modulated by the photoisomerization of pyrazolones. - Highlights: • A solid-state fluorescence photoswitching material was prepared. • Photoswitching is due to energy transfer between pyrazolone and fluorescence dye. • It exhibits excellent fluorescence contrast and fatigue resistance in the solid state.

  7. Afferent fibers of the pudendal nerve modulate sympathetic neurons controlling the bladder neck.

    Science.gov (United States)

    Reitz, André; Schmid, Daniel M; Curt, Armin; Knapp, Peter A; Schurch, Brigitte

    2003-01-01

    Pudendal nerve stimulation is known to have a potential modulative effect on bladder function. However, even if its efficiency has been established for various neurogenic and non-neurogenic bladder dysfunctions, the underlying neuronal mechanism, and the involved pathways in humans remain unknown. In this prospective study we focused on the effects of pudendal nerve stimulation in complete spinal cord injured patients to identify neuromodulative processes that occur on spinal level. Twenty complete spinal male presenting with upper motor neuron lesion and neurogenic incontinence underwent pudendal nerve stimulation. Bladder, bladder neck (BN), and external urethral sphincter (EUS) pressures were continuously recorded with a three channel microtip pressure transducer catheter. Fifty six pudendal stimulations using biphasic rectangular impulses (0.2 ms, 10 Hz) with intensities up to 100 mA were applied to the dorsal penile nerve. In six patients, 18 stimulations were repeated after intravenous (i.v.) administration of 7 mg phentolamine. Mean BN and EUS pressure increased during stimulation significantly (P stimulation significantly (P nerve stimulation evoked somatic responses in the EUS and autonomic responses in the smooth muscle sphincter controlling the BN. Longer latencies of the BN responses and the sensitivity to the alpha-blocking agent phentolamine suggest that sympathetic alpha-adrenergic fibers are involved. Somatic afferent fibers of the pudendal nerve are supposed to project on sympathetic thoracolumbar neurons to the BN and modulate their function. This neuromodulative effect works exclusively at the spinal level and appears to be at least partly responsible for BN competence and at least continence. Copyright 2003 Wiley-Liss, Inc.

  8. Abdicating power for control: a precision timing strategy to modulate function of flight power muscles

    Science.gov (United States)

    Sponberg, S.; Daniel, T. L.

    2012-01-01

    Muscles driving rhythmic locomotion typically show strong dependence of power on the timing or phase of activation. This is particularly true in insects' main flight muscles, canonical examples of muscles thought to have a dedicated power function. However, in the moth (Manduca sexta), these muscles normally activate at a phase where the instantaneous slope of the power–phase curve is steep and well below maximum power. We provide four lines of evidence demonstrating that, contrary to the current paradigm, the moth's nervous system establishes significant control authority in these muscles through precise timing modulation: (i) left–right pairs of flight muscles normally fire precisely, within 0.5–0.6 ms of each other; (ii) during a yawing optomotor response, left—right muscle timing differences shift throughout a wider 8 ms timing window, enabling at least a 50 per cent left–right power differential; (iii) timing differences correlate with turning torque; and (iv) the downstroke power muscles alone causally account for 47 per cent of turning torque. To establish (iv), we altered muscle activation during intact behaviour by stimulating individual muscle potentials to impose left—right timing differences. Because many organisms also have muscles operating with high power–phase gains (Δpower/Δphase), this motor control strategy may be ubiquitous in locomotor systems. PMID:22833272

  9. Abdicating power for control: a precision timing strategy to modulate function of flight power muscles.

    Science.gov (United States)

    Sponberg, S; Daniel, T L

    2012-10-07

    Muscles driving rhythmic locomotion typically show strong dependence of power on the timing or phase of activation. This is particularly true in insects' main flight muscles, canonical examples of muscles thought to have a dedicated power function. However, in the moth (Manduca sexta), these muscles normally activate at a phase where the instantaneous slope of the power-phase curve is steep and well below maximum power. We provide four lines of evidence demonstrating that, contrary to the current paradigm, the moth's nervous system establishes significant control authority in these muscles through precise timing modulation: (i) left-right pairs of flight muscles normally fire precisely, within 0.5-0.6 ms of each other; (ii) during a yawing optomotor response, left-right muscle timing differences shift throughout a wider 8 ms timing window, enabling at least a 50 per cent left-right power differential; (iii) timing differences correlate with turning torque; and (iv) the downstroke power muscles alone causally account for 47 per cent of turning torque. To establish (iv), we altered muscle activation during intact behaviour by stimulating individual muscle potentials to impose left-right timing differences. Because many organisms also have muscles operating with high power-phase gains (Δ(power)/Δ(phase)), this motor control strategy may be ubiquitous in locomotor systems.

  10. CLONING AND EXPRESSING TRYPSIN MODULATING OOSTATIC FACTOR IN Chlorella desiccata TO CONTROL MOSQUITO LARVAE.

    Science.gov (United States)

    Borovsky, Dov; Sterner, Andeas; Powell, Charles A

    2016-01-01

    The insect peptide hormone trypsin modulating oostatic factor (TMOF), a decapeptide that is synthesized by the mosquito ovary and controls the translation of the gut's trypsin mRNA was cloned and expressed in the marine alga Chlorella desiccata. To express Aedes aegypti TMOF gene (tmfA) in C. desiccata cells, two plasmids (pYES2/TMOF and pYDB4-tmfA) were engineered with pKYLX71 DNA (5 Kb) carrying the cauliflower mosaic virus (CaMV) promoter 35S(2) and the kanamycin resistant gene (neo), as well as, a 8 Kb nitrate reductase gene (nit) from Chlorella vulgaris. Transforming C. desiccata with pYES2/TMOF and pYDB4-tmfA show that the engineered algal cells express TMOF (20 ± 4 μg ± SEM and 17 ± 3 μg ± SEM, respectively in 3 × 10(8) cells) and feeding the cells to mosquito larvae kill 75 and 60% of Ae. aegypti larvae in 4 days, respectively. Southern and Northern blots analyses show that tmfA integrated into the genome of C. desiccata by homologous recombination using the yeast 2 μ circle of replication and the nit in pYES2/TMOF and pYDB4-tmfA, respectively, and the transformed algal cells express tmfA transcript. Using these algal cells it will be possible in the future to control mosquito larvae in the marsh. © 2015 Wiley Periodicals, Inc.

  11. Validity of joint space width measurements in hand osteoarthritis.

    Science.gov (United States)

    Kwok, W Y; Bijsterbosch, J; Malm, S H; Biermasz, N R; Huetink, K; Nelissen, R G; Meulenbelt, I; Huizinga, T W J; van 't Klooster, R; Stoel, B C; Kloppenburg, M

    2011-11-01

    To investigate the validity of joint space width (JSW) measurements in millimeters (mm) in hand osteoarthritis (OA) patients by comparison to controls, grading of joint space narrowing (JSN), and clinical features. Hand radiographs of 235 hand OA patients (mean age 65 years, 83% women) and 471 controls were used. JSW was measured with semi-automated image analysis software in the distal, proximal interphalangeal and metacarpal joints (DIPJs, PIPJs and MCPJs). JSN (grade 0-3) was assessed using the osteoarthritis research society international (OARSI) atlas. Associations between the two methods and clinical determinants (presence of pain, nodes and/or erosions, decreased mobility) were assessed using Generalized Estimating Equations with adjustments for age, sex, body mass index (BMI) and mean width of proximal phalanx. JSW was measured in 5631 joints with a mean JSW of 0.98 mm (standard deviation (SD) 0.21), being the smallest for DIPJs (0.70 (SD 0.25)) and largest for MCPJs (1.40 (SD 0.25)). The JSN=0 group had a mean JSW of 1.28 mm (SD 0.34), the JSN=3 group 0.17 mm (SD 0.23). Controls had larger JSW than hand OA patients (P-valuemeasurement is a valid method to measure joint space and shows a good relation with clinical features. Copyright © 2011 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

  12. Method and apparatus for active control of combustion rate through modulation of heat transfer from the combustion chamber wall

    Science.gov (United States)

    Roberts, Jr., Charles E.; Chadwell, Christopher J.

    2004-09-21

    The flame propagation rate resulting from a combustion event in the combustion chamber of an internal combustion engine is controlled by modulation of the heat transfer from the combustion flame to the combustion chamber walls. In one embodiment, heat transfer from the combustion flame to the combustion chamber walls is mechanically modulated by a movable member that is inserted into, or withdrawn from, the combustion chamber thereby changing the shape of the combustion chamber and the combustion chamber wall surface area. In another embodiment, heat transfer from the combustion flame to the combustion chamber walls is modulated by cooling the surface of a portion of the combustion chamber wall that is in close proximity to the area of the combustion chamber where flame speed control is desired.

  13. Ramsey fringe width compared to the spectral width of the driving pulse pair

    Science.gov (United States)

    Supplee, James; Makhija

    2008-05-01

    In a population inversion versus detuning curve, fringes due to a Ramsey pulse-pair are vastly narrower than a peak due to just one of the pulses would be. For subtler reasons, the Ramsey fringe width is also less than the inversion peak that would be obtained using one long pulse with duration as long as the entire Ramsey pair including the time between pulses. This narrowing is by a factor of about 0.6 in many typical circumstances, but that factor can vary (sometimes significantly) depending on parameters such as pulse duration, pulse area, and time between pulses. We are doing calculations using an idealized semiclassical model with a two-level quantum system to address the following question: In which parameter regimes is the Ramsey fringe width well explained just by the spectral width of the driving pulse pair?

  14. Post-error action control is neurobehaviorally modulated under conditions of constant speeded response

    Directory of Open Access Journals (Sweden)

    Takahiro eSoshi

    2015-01-01

    Full Text Available Post-error slowing is an error recovery strategy that contributes to action control, and occurs after errors in order to prevent future behavioral flaws. Error recovery often malfunctions in clinical populations, but the relationship between behavioral traits and recovery from error is unclear in healthy populations. The present study investigated the relationship between impulsivity and error recovery by simulating a speeded response situation using a Go/No-go paradigm that forced the participants to constantly make accelerated responses prior to stimuli disappearance (stimulus duration: 250 ms. Neural correlates of post-error processing were examined using event-related potentials (ERPs. Impulsivity traits were measured with self-report questionnaires (BIS-11, BIS/BAS. Behavioral results demonstrated that the commission error for No-go trials was 15%, but post-error slowing did not take place immediately. Delayed post-error slowing was negatively correlated with error rates and impulsivity traits, showing that response slowing was associated with reduced error rates and changed with impulsivity. Response-locked error ERPs were clearly observed for the error trials. Contrary to previous studies, error ERPs were not significantly related to post-error slowing. Stimulus-locked N2 was negatively correlated with post-error slowing and positively correlated with impulsivity traits at the second post-error Go trial: larger N2 activity was associated with greater post-error slowing and less impulsivity. In summary, under constant speeded conditions, error monitoring was dissociated from post-error action control, and post-error slowing did not occur quickly. Furthermore, post-error slowing and its neural correlate (N2 were modulated by impulsivity traits. These findings suggest that there may be clinical and practical efficacy of maintaining cognitive control of actions during error recovery under common daily environments that frequently evoke

  15. Sucrose is an early modulator of the key hormonal mechanisms controlling bud outgrowth in Rosa hybrida.

    Science.gov (United States)

    Barbier, François; Péron, Thomas; Lecerf, Marion; Perez-Garcia, Maria-Dolores; Barrière, Quentin; Rolčík, Jakub; Boutet-Mercey, Stéphanie; Citerne, Sylvie; Lemoine, Remi; Porcheron, Benoît; Roman, Hanaé; Leduc, Nathalie; Le Gourrierec, José; Bertheloot, Jessica; Sakr, Soulaiman

    2015-05-01

    Sugar has only recently been identified as a key player in triggering bud outgrowth, while hormonal control of bud outgrowth is already well established. To get a better understanding of sugar control, the present study investigated how sugar availability modulates the hormonal network during bud outgrowth in Rosa hybrida. Other plant models, for which mutants are available, were used when necessary. Buds were grown in vitro to manipulate available sugars. The temporal patterns of the hormonal regulatory network were assessed in parallel with bud outgrowth dynamics. Sucrose determined bud entrance into sustained growth in a concentration-dependent manner. Sustained growth was accompanied by sustained auxin production in buds, and sustained auxin export in a DR5::GUS-expressing pea line. Several events occurred ahead of sucrose-stimulated bud outgrowth. Sucrose upregulated early auxin synthesis genes (RhTAR1, RhYUC1) and the auxin efflux carrier gene RhPIN1, and promoted PIN1 abundance at the plasma membrane in a pPIN1::PIN1-GFP-expressing tomato line. Sucrose downregulated both RwMAX2, involved in the strigolactone-transduction pathway, and RhBRC1, a repressor of branching, at an early stage. The presence of sucrose also increased stem cytokinin content, but sucrose-promoted bud outgrowth was not related to that pathway. In these processes, several non-metabolizable sucrose analogues induced sustained bud outgrowth in R. hybrida, Pisum sativum, and Arabidopsis thaliana, suggesting that sucrose was involved in a signalling pathway. In conclusion, we identified potential hormonal candidates for bud outgrowth control by sugar. They are central to future investigations aimed at disentangling the processes that underlie regulation of bud outgrowth by sugar. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  16. Fringe structures and tunable bandgap width of 2D boron nitride nanosheets

    Directory of Open Access Journals (Sweden)

    Peter Feng

    2014-07-01

    Full Text Available We report studies of the surface fringe structures and tunable bandgap width of atomic-thin boron nitride nanosheets (BNNSs. BNNSs are synthesized by using digitally controlled pulse deposition techniques. The nanoscale morphologies of BNNSs are characterized by using scanning electron microscope (SEM, and transmission electron microscopy (TEM. In general, the BNNSs appear microscopically flat in the case of low temperature synthesis, whereas at high temperature conditions, it yields various curved structures. Experimental data reveal the evolutions of fringe structures. Functionalization of the BNNSs is completed with hydrogen plasma beam source in order to efficiently control bandgap width. The characterizations are based on Raman scattering spectroscopy, X-ray diffraction (XRD, and FTIR transmittance spectra. Red shifts of spectral lines are clearly visible after the functionalization, indicating the bandgap width of the BNNSs has been changed. However, simple treatments with hydrogen gas do not affect the bandgap width of the BNNSs.

  17. Distinct type I and type II toxin-antitoxin modules control Salmonella lifestyle inside eukaryotic cells

    National Research Council Canada - National Science Library

    Lobato-Márquez, Damián; Moreno-Córdoba, Inmaculada; Figueroa, Virginia; Díaz-Orejas, Ramón; García-del Portillo, Francisco

    2015-01-01

    .... Using the intracellular bacterial pathogen Salmonella enterica serovar Typhimurium as a model, here we show that a selected group of TA modules impact bacterial fitness inside eukaryotic cells...

  18. Statistical process control applied to intensity modulated radiotherapy pretreatment controls with portal dosimetry;Maitrise statistique des processus appliquee aux controles avant traitement par dosimetrie portale en radiotherapie conformationnelle avec modulation d'intensite

    Energy Technology Data Exchange (ETDEWEB)

    Villani, N.; Noel, A. [Laboratoire de recherche en radiophysique, CRAN UMR 7039, Nancy universite-CNRS, 54 - Vandoeuvre-les-Nancy (France); Villani, N.; Gerard, K.; Marchesi, V.; Huger, S.; Noel, A. [Departement de radiophysique, centre Alexis-Vautrin, 54 - Vandoeuvre-les-Nancy (France); Francois, P. [Institut Curie, 75 - Paris (France)

    2010-06-15

    Purpose The first purpose of this study was to illustrate the contribution of statistical process control for a better security in intensity modulated radiotherapy (I.M.R.T.) treatments. This improvement is possible by controlling the dose delivery process, characterized by pretreatment quality control results. So, it is necessary to put under control portal dosimetry measurements (currently, the ionisation chamber measurements were already monitored by statistical process control thanks to statistical process control tools). The second objective was to state whether it is possible to substitute ionisation chamber with portal dosimetry in order to optimize time devoted to pretreatment quality control. Patients and methods At Alexis-Vautrin center, pretreatment quality controls in I.M.R.T. for prostate and head and neck treatments were performed for each beam of each patient. These controls were made with an ionisation chamber, which is the reference detector for the absolute dose measurement, and with portal dosimetry for the verification of dose distribution. Statistical process control is a statistical analysis method, coming from industry, used to control and improve the studied process quality. It uses graphic tools as control maps to follow-up process, warning the operator in case of failure, and quantitative tools to evaluate the process toward its ability to respect guidelines: this is the capability study. The study was performed on 450 head and neck beams and on 100 prostate beams. Results Control charts, showing drifts, both slow and weak, and also both strong and fast, of mean and standard deviation have been established and have shown special cause introduced (manual shift of the leaf gap of the multi-leaf collimator). Correlation between dose measured at one point, given with the E.P.I.D. and the ionisation chamber has been evaluated at more than 97% and disagreement cases between the two measurements were identified. Conclusion The study allowed to

  19. Isolated PDM and PWM DC-AC SICAMs[Pulse Density Modulated; Pulse Width Modulated

    Energy Technology Data Exchange (ETDEWEB)

    Ljusev, P.

    2004-03-15

    In this report a class of isolated PDM and PWM DC-AC SICAMs is described, which introduce the audio reference only in the output stage. AC-DC power supply is implemented in its simplest form: diode rectifier followed by a medium-size charge-storage capacitor. Isolation from the AC mains is achieved using a high frequency (HF) transformer, receiving the HF voltage pulses from the input 'inverter' stage and transferring them to the output 'rectifier+inverter' stage, which can use either PDM or PWM. The latter stage is then interfaced to the load using an output low-pass filter. Each of the dedicated stages is discussed in detail. Measurements on the master/slave PWM DC-AC SICAM prototype are presented to help benchmarking the performance of this class of SICAMs and identify the advantages and drawbacks. (au)

  20. Modulation of Posterior Alpha Activity by Spatial Attention Allows for Controlling A Continuous Brain-Computer Interface

    NARCIS (Netherlands)

    Horschig, J.M.; Oosterheert, W.; Oostenveld, R.; Jensen, O.

    2015-01-01

    Here we report that the modulation of alpha activity by covert attention can be used as a control signal in an online brain-computer interface, that it is reliable, and that it is robust. Subjects were instructed to orient covert visual attention to the left or right hemifield. We decoded the

  1. Analysis of bus width and delay on a fully digital signum nonlinearity chaotic oscillator

    KAUST Repository

    Mansingka, Abhinav S.

    2012-07-29

    This paper introduces the first fully digital implementation of a 3rd order ODE-based chaotic oscillator with signum nonlinearity. A threshold bus width of 12-bits for reliable chaotic behavior is observed, below which the system output becomes periodic. Beyond this threshold, the maximum Lyapunov exponent (MLE) is shown to improve up to a peak value at 16-bits and subsequently decrease with increasing bus width. The MLE is also shown to gradually increase with number of introduced internal delay cycles until a peak value at 14 cycles, after which the system loses chaotic properties. Introduced external delay cycles are shown to rotate the attractors in 3-D phase space. Bus width and delay elements can be independently modulated to optimize the system to suit specifications. The experimental results of the system show low area and high performance on a Xilinx Virtex 4 FPGA with throughput of 13.35 Gbits/s for a 32-bit implementation.

  2. Lake Basin Fetch and Maximum Length/Width

    Data.gov (United States)

    Minnesota Department of Natural Resources — Linear features representing the Fetch, Maximum Length and Maximum Width of a lake basin. Fetch, maximum length and average width are calcuated from the lake polygon...

  3. Scanning ion conductance microscopy with distance-modulated shear force control

    Science.gov (United States)

    Böcker, Matthias; Anczykowski, Boris; Wegener, Joachim; Schäffer, Tilman E.

    2007-04-01

    A scanning ion conductance microscope (SICM) is based on a tapered nanopipette as a nanoscale conductance probe that is scanned over a sample submerged in an electrolyte solution. In conventional SICM scanning the ion current through the pipette aperture is at the nano- and picoampere level and is influenced by both sample topography and local conductance. Here we present an SICM with integrated shear-force distance control that allows measuring the ion current independently of sample topography. The nanopipette is hereby transversally vibrated and the shear forces that arise are detected optically with the help of two periscopes that are partially submerged in the electrolyte. We also present a new imaging mode designed to facilitate shear-force imaging of soft samples. This mode is based on a periodic modulation of the pipette-sample distance combined with triggered sampling, reducing the probability for sample and pipette damage and increasing the image quality. We apply this imaging mode to polycarbonate membranes and mammalian cells.

  4. Statistical process control analysis for patient quality assurance of intensity modulated radiation therapy

    Science.gov (United States)

    Lee, Rena; Kim, Kyubo; Cho, Samju; Lim, Sangwook; Lee, Suk; Shim, Jang Bo; Huh, Hyun Do; Lee, Sang Hoon; Ahn, Sohyun

    2017-11-01

    This study applied statistical process control to set and verify the quality assurances (QA) tolerance standard for our hospital's characteristics with the criteria standards that are applied to all the treatment sites with this analysis. Gamma test factor of delivery quality assurances (DQA) was based on 3%/3 mm. Head and neck, breast, prostate cases of intensity modulated radiation therapy (IMRT) or volumetric arc radiation therapy (VMAT) were selected for the analysis of the QA treatment sites. The numbers of data used in the analysis were 73 and 68 for head and neck patients. Prostate and breast were 49 and 152 by MapCHECK and ArcCHECK respectively. C p value of head and neck and prostate QA were above 1.0, C pml is 1.53 and 1.71 respectively, which is close to the target value of 100%. C pml value of breast (IMRT) was 1.67, data values are close to the target value of 95%. But value of was 0.90, which means that the data values are widely distributed. C p and C pml of breast VMAT QA were respectively 1.07 and 2.10. This suggests that the VMAT QA has better process capability than the IMRT QA. Consequently, we should pay more attention to planning and QA before treatment for breast Radiotherapy.

  5. Attention modulates cortical processing of pitch feedback errors in voice control.

    Science.gov (United States)

    Hu, Huijing; Liu, Ying; Guo, Zhiqiang; Li, Weifeng; Liu, Peng; Chen, Shaozhen; Liu, Hanjun

    2015-01-15

    Considerable evidence has shown that unexpected alterations in auditory feedback elicit fast compensatory adjustments in vocal production. Although generally thought to be involuntary in nature, whether these adjustments can be influenced by attention remains unknown. The present event-related potential (ERP) study aimed to examine whether neurobehavioral processing of auditory-vocal integration can be affected by attention. While sustaining a vowel phonation and hearing pitch-shifted feedback, participants were required to either ignore the pitch perturbations, or attend to them with low (counting the number of perturbations) or high attentional load (counting the type of perturbations). Behavioral results revealed no systematic change of vocal response to pitch perturbations irrespective of whether they were attended or not. At the level of cortex, there was an enhancement of P2 response to attended pitch perturbations in the low-load condition as compared to when they were ignored. In the high-load condition, however, P2 response did not differ from that in the ignored condition. These findings provide the first neurophysiological evidence that auditory-motor integration in voice control can be modulated as a function of attention at the level of cortex. Furthermore, this modulatory effect does not lead to a general enhancement but is subject to attentional load.

  6. Phytoestrogens modulate hepcidin expression by Nrf2: Implications for dietary control of iron absorption

    Science.gov (United States)

    Bayele, Henry K.; Balesaria, Sara; Srai, Surjit K.S.

    2015-01-01

    Hepcidin is a liver-derived antimicrobial peptide that regulates iron absorption and is also an integral part of the acute phase response. In a previous report, we found evidence that this peptide could also be induced by toxic heavy metals and xenobiotics, thus broadening its teleological role as a defensin. However it remained unclear how its sensing of disparate biotic and abiotic stressors might be integrated at the transcriptional level. We hypothesized that its function in cytoprotection may be regulated by NFE2-related factor 2 (Nrf2), the master transcriptional controller of cellular stress defenses. In this report, we show that hepcidin regulation is inextricably linked to the acute stress response through Nrf2 signaling. Nrf2 regulates hepcidin expression from a prototypical antioxidant response element in its promoter, and by synergizing with other basic leucine-zipper transcription factors. We also show that polyphenolic small molecules or phytoestrogens commonly found in fruits and vegetables including the red wine constituent resveratrol can induce hepcidin expression in vitro and post-prandially, with concomitant reductions in circulating iron levels and transferrin saturation by one such polyphenol quercetin. Furthermore, these molecules derepress hepcidin promoter activity when its transcription by Nrf2 is repressed by Keap1. Taken together, the data show that hepcidin is a prototypical antioxidant response or cytoprotective gene within the Nrf2 transcriptional circuitry. The ability of phytoestrogens to modulate hepcidin expression in vivo suggests a novel mechanism by which diet may impact iron homeostasis. PMID:26546695

  7. Gener: a minimal programming module for chemical controllers based on DNA strand displacement.

    Science.gov (United States)

    Kahramanoğulları, Ozan; Cardelli, Luca

    2015-09-01

    : Gener is a development module for programming chemical controllers based on DNA strand displacement. Gener is developed with the aim of providing a simple interface that minimizes the opportunities for programming errors: Gener allows the user to test the computations of the DNA programs based on a simple two-domain strand displacement algebra, the minimal available so far. The tool allows the user to perform stepwise computations with respect to the rules of the algebra as well as exhaustive search of the computation space with different options for exploration and visualization. Gener can be used in combination with existing tools, and in particular, its programs can be exported to Microsoft Research's DSD tool as well as to LaTeX. Gener is available for download at the Cosbi website at http://www.cosbi.eu/research/prototypes/gener as a windows executable that can be run on Mac OS X and Linux by using Mono. ozan@cosbi.eu. © The Author 2015. Published by Oxford University Press.

  8. Dynamic control of the complement system by modulated expression of regulatory proteins.

    Science.gov (United States)

    Thurman, Joshua M; Renner, Brandon

    2011-01-01

    The complement system serves many biological functions, including the eradication of invasive pathogens and the removal of damaged cells and immune-complexes. Uncontrolled complement activation causes injury to host cells, however, so adequate regulation of the system is essential. Control of the complement system is maintained by a group of cell surface and circulating proteins referred to as complement regulatory proteins. The expression of the cell surface complement regulatory proteins varies from tissue to tissue. Furthermore, specific cell types can upregulate or downregulate the expression of these proteins in response to a variety of signals or insults. Altered regulation of the complement regulatory proteins can have important effects on local complement activation. In some circumstances this can be beneficial, such as in the setting of certain infections. In other circumstances, however, this can be a cause of complement-mediated injury of the tissue. A full understanding of the mechanisms by which the complement system is modulated at the local level can have important implications for how we diagnose and treat a wide range of inflammatory diseases.

  9. A Module For Thermal Pest Control In Stored Raw Materials Used In ...

    African Journals Online (AJOL)

    The module is an engineering contraption, which uses steam to raise temperature within it to insecticidal levels (above 45 °C). This causes halt in development and proein denaturing (leading to mortality) of the pests (eggs, larvae and adults). This applied heat also toasts the material inside the module thereby improving ...

  10. Direct measurement of the W boson width

    Energy Technology Data Exchange (ETDEWEB)

    Abazov, V.M.; /Dubna, JINR; Abbott, B.; /Oklahoma U.; Abolins, M.; /Michigan State U.; Acharya, B.S.; /Tata Inst.; Adams, M.; /Illinois U., Chicago; Adams, T.; /Florida State U.; Aguilo, E.; /Alberta U. /Simon Fraser U. /McGill U.; Ahsan, M.; /Kansas State U.; Alexeev, G.D.; /Dubna, JINR; Alkhazov, G.; /St. Petersburg, INP; Alton, A.; /Michigan U. /Northeastern U.

    2009-09-01

    We present a direct measurement of the width of the W boson using the shape of the transverse mass distribution of W {yields} e{nu} candidates selected in 1 fb{sup -1} of data collected with the D0 detector at the Fermilab Tevatron collider in p{bar p} collisions at {radical}s = 1.96 TeV. We use the same methods and data sample that were used for our recently published W boson mass measurement, except for the modeling of the recoil, which is done with a new method based on a recoil library. Our result, 2.028 {+-} 0.072 GeV, is in agreement with the predictions of the standard model and is the most precise direct measurement result from a single experiment to date.

  11. Half-width at half-maximum, full-width at half-maximum analysis for ...

    Indian Academy of Sciences (India)

    In the present study, HWHM (half-width at half-maximum) of the resultant PSF has been defined to characterize the resolution of the detection system. ... Department of Physics, University College of Science, Osmania University, Hyderabad 500 007, India; Department of Humanities & Sciences, C.M.R. Institute of Technology ...

  12. Positron emission tomography and target-controlled infusion for precise modulation of brain drug concentration

    Energy Technology Data Exchange (ETDEWEB)

    Eriksson, Olof [Uppsala Imanet AB, 751 85 Uppsala (Sweden); Department of Radiology, Oncology and Clinical Immunology, Division of Radiology, Uppsala University, 751 85 Uppsala (Sweden)], E-mail: olof.eriksson@uppsala.imanet.se; Josephsson, Ray [Clinical Imaging Unit, Novartis Pharma AG, CH 9057 Basel (Switzerland); Langstrom, Bengt [Uppsala Imanet AB, 751 85 Uppsala (Sweden); Bergstroem, Mats [Department of Pharmaceutical Biosciences, Faculty of Pharmacy, Uppsala University, 751 24 Uppsala (Sweden)

    2008-04-15

    Introduction: There are several instances when it is desirable to control brain concentration of pharmaceuticals, e.g., to modulate the concentration of anesthetic agents to different desired levels fitting to different needs during the course of surgery. This has so far only been possible using indirect estimates of drug concentration such as assuming constant relation between tissue and blood including extrapolations from animals. Methods: A system for controlling target tissue concentration (UIPump) was used to regulate whole-brain concentrations of a central benzodiazepine receptor antagonist at therapeutic levels with input from brain kinetics as determined with PET. The system was tested by using pharmacological doses of flumazenil mixed with tracer amounts of [{sup 11}C]flumazenil. Flumazenil was used as a model compound for anesthesia. An infusion scheme to produce three different steady-state levels in sequence was designed based on kinetic curves obtained after bolus injection. The subjects (Sprague-Dawley rats, n=6) were monitored in a microPET scanner during the whole experiment to verify resulting brain kinetic curves. Results: A steady-state brain concentration was rapidly achieved corresponding to a whole-brain concentration of 118{+-}6 ng/ml. As the infusion rate decreased to lower the exposure by a factor of 2, the brain concentration decreased to 56{+-}4 ng/ml. A third increased steady-state level of anesthesia corresponding to a whole-brain concentration of 107{+-}7 ng/ml was rapidly achieved. Conclusion: The experimental setup with computerized pump infusion and PET supervision enables accurate setting of target tissue drug concentration.

  13. Modulation and Control of Charge Transport Through Single-Molecule Junctions.

    Science.gov (United States)

    Wang, Kun; Xu, Bingqian

    2017-02-01

    The ability to modulate and control charge transport though single-molecule junction devices is crucial to achieving the ultimate goal of molecular electronics: constructing real-world-applicable electronic components from single molecules. This review aims to highlight the progress made in single-molecule electronics, emphasizing the development of molecular junction electronics in recent years. Among many techniques that attempt to wire a molecule to metallic electrodes, the single-molecule break junction (SMBJ) technique is one of the most reliable and tunable experimental platforms for achieving metal-molecule-metal configurations. It also provides great freedom to tune charge transport through the junction. Soon after the SMBJ technique was introduced, it was extensively used to measure the conductances of individual molecules; however, different conductances were obtained for the same molecule, and it proved difficult to interpret this wide distribution of experimental data. This phenomenon was later found to be mainly due to a lack of precise experimental control and advanced data analysis methods. In recent years, researchers have directed considerable effort into advancing the SMBJ technique by gaining a deeper physical understanding of charge transport through single molecules and thus enhancing its potential applicability in functional molecular-scale electronic devices, such as molecular diodes and molecular transistors. In parallel with that research, novel data analysis methods and approaches that enable the discovery of hidden yet important features in the data are being developed. This review discusses various aspects of molecular junction electronics, from the initial goal of molecular electronics, the development of experimental techniques for creating single-molecule junctions and determining single-molecule conductance, to the characterization of functional current-voltage features and the investigation of physical properties other than charge

  14. Coupling Temperature Control with Electrochemically Modulated Liquid Chromatography: Fundamental Aspects and Applications

    Energy Technology Data Exchange (ETDEWEB)

    Ponton, Lisa M. [Iowa State Univ., Ames, IA (United States)

    2004-12-19

    The primary focus of the doctoral research presented herein has been the integration of temperature control into electrochemically modulated liquid chromatography (EMLC). The combination of temperature control and the tunable characteristics of carbonaceous EMLC stationary phases have been invaluable in deciphering the subtleties of the retention mechanism. The effects of temperature and Eapp on the retention of several naphthalene disulfonates were therefore examined by the van' Hoff relationship. The results indicate that while the retention of both compounds is exothermic at levels comparable to that in many reversed-phase separations, the potential dependence of the separation is actually entropically affected in a manner paralleling that of several classical ion exchange systems. Furthermore, the retention of small inorganic anions at constant temperature also showed evidence of an ion exchange type of mechanism. While a more complete mechanistic description will come from examining the thermodynamics of retention for a wider variety of analytes, this research has laid the groundwork for full exploitation of temperature as a tool to develop retention rules for EMLC. Operating EMLC at elevated temperature and flow conditions has decreased analysis time and has enabled the separation of analytes not normally achievable on a carbon stationary phase. The separation of several aromatic sulfonates was achieved in less than 1 min, a reduction of analysis time by more than a factor of 20 as compared to room temperature separations. The use of higher operating temperatures also facilitated the separation of this mixture with an entirely aqueous mobile phase in less than 2 min. This methodology was extended to the difficult separation of polycyclic aromatic hydrocarbons on PGC. This study also brought to light the mechanistic implications of the unique retention behavior of these analytes through variations of the mobile phase composition.

  15. Dose-painted intensity modulated radiation therapy improves local control for locally advanced pancreas cancer.

    Science.gov (United States)

    Tunceroglu, Ahmet; Park, Joo Han; Balasubramanian, Sairam; Poppe, Matthew; Anker, Christopher J; Poplin, Elizabeth; Moss, Rebecca A; Yue, Ning J; Carpizo, Darren; Gannon, Christopher J; Haffty, Bruce G; Jabbour, Salma K

    2012-01-01

    Background. To evaluate the outcomes, adverse events, and therapeutic role of Dose-Painted Intensity-Modulated Radiation Therapy (DP-IMRT) for locally advanced pancreas cancer (LAPC). Methods. Patients with LAPC were treated with induction chemotherapy (n = 25) and those without metastasis (n = 20) received DP-IMRT consisting of 45 Gy to Planning Treatment Volume 1 (PTV1) including regional lymph nodes with a concomitant boost to the PTV2 (gross tumor volume + 0.5 cm) to either 50.4 Gy (n = 9) or 54 Gy (n = 11) in 25 fractions. DP-IMRT cases were compared to three-dimensional conformal radiation therapy (3D-CRT) plans to assess the potential relationship of radiation dose to adverse events. Kaplan-Meier and Cox regression analyses were used to calculate survival probabilities. The Fisher exact test and t-test were utilized to investigate potential prognostic factors of toxicity and survival. Results. Median overall and progression-free survivals were 11.6 and 5.9 months, respectively. Local control was 90%. Post-RT CA-19-9 levels following RT were predictive of survival (P = 0.02). Grade 2 and ≥grade 3 GI toxicity were 60% and 20%, respectively. In comparison to 3D-CRT, DP-IMRT plans demonstrated significantly lower V45 values of small bowel (P = 0.0002), stomach (P = 0.007), and mean liver doses (P = 0.001). Conclusions. Dose-escalated DP-IMRT offers improved local control in patients treated with induction chemotherapy for LAPC. Radiation-related morbidity appears reduced with DP-IMRT compared to 3D-CRT techniques, likely due to reduction in RT doses to organs at risk.

  16. Motivational intensity modulates the effects of positive emotions on set shifting after controlling physiological arousal.

    Science.gov (United States)

    Zhou, Ya; Siu, Angela F Y

    2015-12-01

    Recent research on the construct of emotion suggests the integration of a motivational dimension into the traditional two-dimension (subjective valence and physiological arousal) model. The motivational intensity of an emotional state should be taken into account while investigating the emotion-cognition relationship. This study examined how positive emotional states varying in motivational intensity influenced set shifting, after controlling the potential confounding impacts of physiological arousal. In Experiment 1, 155 volunteers performed a set-shifting task after being randomly assigned to five states: high- vs. low-motivating positive affect (interest vs. serenity), high- vs. low-motivating negative affect (disgust vs. anxiety), and neutral state. Eighty-five volunteers participated in Experiment 2, which further examined the effects of higher vs. lower degree of interest. Both experiments measured and compared participants' physiological arousal (blood pressure and pulse rate) under the normal and experimental conditions as the covariate. Results showed no difference in switching performance between the neutral and serenity groups. As compared with the neutral state, the high-motivating positive affect significantly increased set-switching reaction time costs, but reduced error rate costs; the higher the motivational intensity, the greater the time-costs impairment. This indicates a role of the high-motivating positive affect in regulating the balance between the flexible and stable cognitive control. Motivational intensity also modulated the effects of negative emotional states, i.e., disgust caused a larger increase in time costs than anxiety. Further exploration into neurobiological mechanisms that may mediate the emotional effects on set shifting is warranted. © 2015 Scandinavian Psychological Associations and John Wiley & Sons Ltd.

  17. GAP WIDTH STUDY IN LASER BUTT-WELDING

    DEFF Research Database (Denmark)

    Gong, Hui; Olsen, Flemming Ove

    In this paper the maximum allowable gap width in laser butt-welding is intensively studied. The gap width study (GWS) is performed on the material of SST of W1.4401 (AISI 316) under various welding conditions, which are the gap width : 0.00-0.50 mm, the welding speed : 0.5-2.0 m/min, the laser po...

  18. Enhancement of heat transfer using varying width twisted tape inserts

    African Journals Online (AJOL)

    ... developed for friction factors and Nusselt numbers for a fully developed turbulent swirl flow, which are applicable to full width as well as reduced width twisted tapes, using a modified twist ratio as pitch to width ratio of the tape. International Journal of Engineering, Science and Technology, Vol. 2, No. 6, 2010, pp. 107-118 ...

  19. Subject-specific modulation of local field potential spectral power during brain-machine interface control in primates

    Science.gov (United States)

    So, Kelvin; Dangi, Siddharth; Orsborn, Amy L.; Gastpar, Michael C.; Carmena, Jose M.

    2014-04-01

    Objective. Intracortical brain-machine interfaces (BMIs) have predominantly utilized spike activity as the control signal. However, an increasing number of studies have shown the utility of local field potentials (LFPs) for decoding motor related signals. Currently, it is unclear how well different LFP frequencies can serve as features for continuous, closed-loop BMI control. Approach. We demonstrate 2D continuous LFP-based BMI control using closed-loop decoder adaptation, which adapts decoder parameters to subject-specific LFP feature modulations during BMI control. We trained two macaque monkeys to control a 2D cursor in a center-out task by modulating LFP power in the 0-150 Hz range. Main results. While both monkeys attained control, they used different strategies involving different frequency bands. One monkey primarily utilized the low-frequency spectrum (0-80 Hz), which was highly correlated between channels, and obtained proficient performance even with a single channel. In contrast, the other monkey relied more on higher frequencies (80-150 Hz), which were less correlated between channels, and had greater difficulty with control as the number of channels decreased. We then restricted the monkeys to use only various sub-ranges (0-40, 40-80, and 80-150 Hz) of the 0-150 Hz band. Interestingly, although both monkeys performed better with some sub-ranges than others, they were able to achieve BMI control with all sub-ranges after decoder adaptation, demonstrating broad flexibility in the frequencies that could potentially be used for LFP-based BMI control. Significance. Overall, our results demonstrate proficient, continuous BMI control using LFPs and provide insight into the subject-specific spectral patterns of LFP activity modulated during control.

  20. EMC of Frequency Controlled Electric Drives

    Directory of Open Access Journals (Sweden)

    R. Dolecek

    2008-12-01

    Full Text Available The paper deals with solution possibilities of EMC for voltage inverters, which uses PWM (Pulse Width Modulation. The paper offers solution of interference suppression which is raised by operation of frequency controlled drives. Possible interferences caused by inverters and their solutions are described at the first part of paper and real solution examples at the end of paper.

  1. Polarization-independent electro-optic modulator based on PMNT electrically-controlled birefringence effect and Sagnac interferometer

    Science.gov (United States)

    Zhang, Xuejiao; Ye, Qing; Cai, Haiwen; Qu, Ronghui

    2014-04-01

    A novel polarization-independent electro-optic modulator is proposed and investigated by using the electrically-controlled birefringence effect of transparent lead magnesium niobate titanate (PMNT) electro-optic ceramic and a Sagnac interferometer structure. The PMNT electro-optic ceramic is used as a phase retarder for two counter-propagating waves in which their polarization directions are adjusted to parallel and vertical to the electrical-field vector respectively. Then the output light intensity from the Sagnac interferometer will be modulated completely with the driven electrical signal and it is independent with the polarization direction of incident light. The extinction ratio is more than 21 dB. This modulated device will be very appropriate as a Q-switch or optical attenuator in the high power laser system.

  2. Evaluation of an active learning module to teach hazard and risk in Hazard Analysis and Critical Control Points (HACCP) classes.

    Science.gov (United States)

    Oyarzabal, Omar A; Rowe, Ellen

    2017-04-01

    The terms hazard and risk are significant building blocks for the organization of risk-based food safety plans. Unfortunately, these terms are not clear for some personnel working in food manufacturing facilities. In addition, there are few examples of active learning modules for teaching adult participants the principles of hazard analysis and critical control points (HACCP). In this study, we evaluated the effectiveness of an active learning module to teach hazard and risk to participants of HACCP classes provided by the University of Vermont Extension in 2015 and 2016. This interactive module is comprised of a questionnaire; group playing of a dice game that we have previously introduced in the teaching of HACCP; the discussion of the terms hazard and risk; and a self-assessment questionnaire to evaluate the teaching of hazard and risk. From 71 adult participants that completed this module, 40 participants (56%) provided the most appropriate definition of hazard, 19 participants (27%) provided the most appropriate definition of risk, 14 participants (20%) provided the most appropriate definitions of both hazard and risk, and 23 participants (32%) did not provide an appropriate definition for hazard or risk. Self-assessment data showed an improvement in the understanding of these terms (P < 0.05). Thirty participants (42%) stated that the most valuable thing they learned with this interactive module was the difference between hazard and risk, and 40 participants (65%) responded that they did not attend similar presentations in the past. The fact that less than one third of the participants answered properly to the definitions of hazard and risk at baseline is not surprising. However, these results highlight the need for the incorporation of modules to discuss these important food safety terms and include more active learning modules to teach food safety classes. This study suggests that active learning helps food personnel better understand important food safety

  3. Evaluation of an active learning module to teach hazard and risk in Hazard Analysis and Critical Control Points (HACCP classes

    Directory of Open Access Journals (Sweden)

    Omar A. Oyarzabal

    2017-04-01

    Full Text Available The terms hazard and risk are significant building blocks for the organization of risk-based food safety plans. Unfortunately, these terms are not clear for some personnel working in food manufacturing facilities. In addition, there are few examples of active learning modules for teaching adult participants the principles of hazard analysis and critical control points (HACCP. In this study, we evaluated the effectiveness of an active learning module to teach hazard and risk to participants of HACCP classes provided by the University of Vermont Extension in 2015 and 2016. This interactive module is comprised of a questionnaire; group playing of a dice game that we have previously introduced in the teaching of HACCP; the discussion of the terms hazard and risk; and a self-assessment questionnaire to evaluate the teaching of hazard and risk. From 71 adult participants that completed this module, 40 participants (56% provided the most appropriate definition of hazard, 19 participants (27% provided the most appropriate definition of risk, 14 participants (20% provided the most appropriate definitions of both hazard and risk, and 23 participants (32% did not provide an appropriate definition for hazard or risk. Self-assessment data showed an improvement in the understanding of these terms (P < 0.05. Thirty participants (42% stated that the most valuable thing they learned with this interactive module was the difference between hazard and risk, and 40 participants (65% responded that they did not attend similar presentations in the past. The fact that less than one third of the participants answered properly to the definitions of hazard and risk at baseline is not surprising. However, these results highlight the need for the incorporation of modules to discuss these important food safety terms and include more active learning modules to teach food safety classes. This study suggests that active learning helps food personnel better understand important

  4. Ageing effects on medio-lateral balance during walking with increased and decreased step width.

    Science.gov (United States)

    Nagano, H; Begg, R; Sparrow, W A

    2013-01-01

    The current study used falls direction to categorize falls and explore age-related effects on the biomechanics of medio-lateral balance control. Minimum lateral margin (MLM) was defined as the critical swing phase event where the medio-lateral length between center of mass (CoM) and stance heel became minimum and accordingly, any lateral balance perturbation at MLM was considered to increase the risk of balance loss lateral to the stance foot. Lateral center of pressure (CoP) displacement from toe-off to MLM was also monitored to assess the risk of medio-lateral balance perturbation. Gait testing involving 30 young and 26 older male subjects was conducted under the three step width conditions: preferred and ± 50% wider and narrower. For an overall description of gait, spatio-temporal parameters were also obtained. Typical ageing effects on spatio-temporal parameters such as lower step velocity, shorter step length and prolonged double support time were found, emerging most clearly in narrower, followed by wider and least in preferred width walking. MLM and CoP lateral displacement were not differentiated between the two age groups, but older adults demonstrated significantly more variable MLM and CoP in their non-dominant limb when walking with non-preferred widths. Variability of step width reduced in increased and decreased step width conditions while MLM and CoP variability increased, suggesting less consistent medio-lateral CoM control despite consistent foot control in altered width conditions. In summary, older adults were found to have less consistent control of CoM with respect to the non-dominant stance foot when walking with narrower and wider widths possibly due to more variable medio-lateral CoP control.

  5. A modelling and simulation of a sensorless control of five-phase PMSM drives using multi-dimension space vector modulation

    OpenAIRE

    Saleh, Kamel; Sumner, Mark

    2016-01-01

    This paper introduces a new method to track the saturation saliency for position measurement of a five-phase PMSM motor fed by a five-phase inverter through measuring the dynamic current response of the motor line currents due to the IGBT switching actions. The new method uses only the fundamental PWM waveform obtained using the multi-phase space vector pulse width modulation (i.e there is no modification to the operation of the five-phase inverter) similar to the fundamental PWM method propo...

  6. Collaborative Synchronization Digital Control for Double Hydraulic Cylinders

    Directory of Open Access Journals (Sweden)

    Zhi-hao Liu

    2014-09-01

    Full Text Available By researching the synchronization motion of double hydraulic cylinders controlled by high-speed on-off valve, the paper aims to solve the shortage of current hydraulic synchronization system with low synchronization precision. The flow characteristic of high-speed on-off valve with pulse width-frequency modulation is researched compared with pulse width modulation. The mathematical equations of the double hydraulic cylinders are formulated with bulk-cavity-node method in MATLAB/Simulink. The collaborative synchronization control is analyzed and the compound algorithm of collaborative synchronization control and pulse width-frequency modulation is simulated compared with collaborative synchronization control. The hydraulic loop is set up to verify the simulation result with the proposed control algorithm on the FESTO platform. The research finds that (1 the pulse width-frequency modulation control can be linear to the flow of high-speed on-off valve on the duty bound of 0~100%; (2 the collaborative synchronization control is effective to eliminate the displacement error between the double cylinders which results from the different load environment and other disturbance.

  7. Reinforcement learning modulates the stability of cognitive control settings for object selection

    Directory of Open Access Journals (Sweden)

    Anthony William Sali

    2013-12-01

    Full Text Available Cognitive flexibility reflects both a trait that reliably differs between individuals and a state that can fluctuate moment-to-moment. Whether individuals can undergo persistent changes in cognitive flexibility as a result of reward learning is less understood. Here, we investigated whether reinforcing a periodic shift in an object selection strategy can make an individual more prone to switch strategies in a subsequent unrelated task. Participants completed two different choice tasks in which they selected one of four objects in an attempt to obtain a hidden reward on each trial. During a training phase, objects were defined by color. Participants received either consistent reward contingencies in which one color was more often rewarded, or contingencies in which the color that was more often rewarded changed periodically and without warning. Following the training phase, all participants completed a test phase in which reward contingencies were defined by spatial location and the location that was more often rewarded remained constant across the entire task. Those participants who received inconsistent contingencies during training continued to make more variable selections during the test phase in comparison to those who received the consistent training. Furthermore, a difference in the likelihood to switch selections on a trial-by-trial basis emerged between training groups: participants who received consistent contingencies during training were less likely to switch object selections following an unrewarded trial and more likely to repeat a selection following reward. Our findings provide evidence that the extent to which priority shifting is reinforced modulates the stability of cognitive control settings in a persistent manner, such that individuals become generally more or less prone to shifting priorities in the future.

  8. Modulation of renal sympathetic innervation: recent insights beyond blood pressure control.

    Science.gov (United States)

    Linz, Dominik; Hohl, Mathias; Elliott, Adrian D; Lau, Dennis H; Mahfoud, Felix; Esler, Murray D; Sanders, Prashanthan; Böhm, Michael

    2018-02-10

    Renal afferent and efferent sympathetic nerves are involved in the regulation of blood pressure and have a pathophysiological role in hypertension. Additionally, several conditions that frequently coexist with hypertension, such as heart failure, obstructive sleep apnea, atrial fibrillation, renal dysfunction, and metabolic syndrome, demonstrate enhanced sympathetic activity. Renal denervation (RDN) is an approach to reduce renal and whole body sympathetic activation. Experimental models indicate that RDN has the potential to lower blood pressure and prevent cardio-renal remodeling in chronic diseases associated with enhanced sympathetic activation. Studies have shown that RDN can reduce blood pressure in drug-naïve hypertensive patients and in hypertensive patients under drug treatment. Beyond its effects on blood pressure, sympathetic modulation by RDN has been shown to have profound effects on cardiac electrophysiology and cardiac arrhythmogenesis. RDN can display anti-arrhythmic effects in a variety of animal models for atrial fibrillation and ventricular arrhythmias. The first non-randomized studies demonstrate that RDN may promote the maintenance of sinus rhythm following catheter ablation in patients with atrial fibrillation. Registry data point towards a beneficial effect of RDN to prevent ventricular arrhythmias in patients with heart failure and electrical storm. Further large randomized placebo-controlled trials are needed to confirm the antihypertensive and anti-arrhythmic effects of RDN. Here, we will review the current literature on anti-arrhythmic effects of RDN with the focus on atrial fibrillation and ventricular arrhythmias. We will discuss new insights from preclinical and clinical mechanistic studies and possible clinical implications of RDN.

  9. Post-injury protective astrogenesis from SVZ niche is controlled by Notch modulator Thbs4

    Science.gov (United States)

    Benner, Eric J.; Luciano, Dominic; Jo, Rebecca; Abdi, Khadar; Paez-Gonzalez, Patricia; Sheng, Huaxin; Warner, David; Liu, Chunlei; Eroglu, Cagla; Kuo, Chay T.

    2013-01-01

    Postnatal/adult neural stem cells (NSCs) within the rodent subventricular/subependymal zone (SVZ/SEZ) generate Doublecortin (DCX)+ neuroblasts that migrate and integrate into olfactory bulb circuitry1,2. Continuous production of neuroblasts is controlled by SVZ microenvironmental niche3,4. It is generally believed that enhancing neurogenic activities of endogenous NSCs may provide needed therapeutic options for disease states and after brain injury. However, SVZ NSCs can also differentiate into astrocytes. It remains unclear if there are conditions that favor astrogenesis over neurogenesis in the SVZ niche, and if astrocytes produced there exhibit different properties from others in the brain. We have uncovered that SVZ-generated astrocytes express high levels of Thrombospondin-4 (Thbs4)5,6, a secreted homopentameric glycoprotein, in contrast to cortical astrocytes which are Thbs4low. We found that localized photothrombotic/ischemic cortical injury initiates a marked increase in Thbs4hi astrocyte production from the postnatal SVZ niche. Tamoxifen-inducible nestin-CreERtm4 lineage-tracing demonstrated that it is these SVZ-generated Thbs4hi astrocytes, and not DCX+ neuroblasts, that home-in on the injured cortex. This robust post-injury astrogenic response required SVZ Notch activation, modulated by Thbs4 via direct Notch1 receptor binding and endocytosis to activate downstream signals, including increased Nfia transcription factor expression important for glia production7. Consequently, Thbs4KO/KO animals showed severe defects in cortical injury-induced SVZ astrogenesis, instead producing cells expressing DCX from SVZ to the injury sites. These alterations in cellular responses resulted in abnormal glial scar formation after injury, and significantly increased microvascular hemorrhage into the brain parenchyma of Thbs4KO/KO animals. Taken together, these findings have significant implications for post-injury applications of endogenous and transplanted NSCs in the

  10. Hydrophilic excipients modulate the time lag of time-controlled disintegrating press-coated tablets.

    Science.gov (United States)

    Lin, Shan-Yang; Li, Mei-Jane; Lin, Kung-Hsu

    2004-08-16

    An oral press-coated tablet was developed by means of direct compression to achieve the time-controlled disintegrating or rupturing function with a distinct predetermined lag time. This press-coated tablet containing sodium diclofenac in the inner core was formulated with an outer shell by different weight ratios of hydrophobic polymer of micronized ethylcellulose (EC) powder and hydrophilic excipients such as spray-dried lactose (SDL) or hydroxypropyl methylcellulose (HPMC). The effect of the formulation of an outer shell comprising both hydrophobic polymer and hydrophilic excipients on the time lag of drug release was investigated. The release profile of the press-coated tablet exhibited a time period without drug release (time lag) followed by a rapid and complete release phase, in which the outer shell ruptured or broke into 2 halves. The lag phase was markedly dependent on the weight ratios of EC/SDL or EC/HPMC in the outer shell. Different time lags of the press-coated tablets from 1.0 to 16.3 hours could be modulated by changing the type and amount of the excipients. A semilogarithmic plot of the time lag of the tablet against the weight ratios of EC/SDL or EC/HPMC in the outer shell demonstrated a good linear relationship, with r = 0.976 and r = 0.982, respectively. The predetermined time lag prior to the drug release from a press-coated tablet prepared by using a micronized EC as a retarding coating shell can be adequately scheduled with the addition of hydrophilic excipients according to the time or site requirements.

  11. Modulation-frequency-controlled change from sub- to superluminal regime in highly doped erbium fibers.

    Science.gov (United States)

    Melle, Sonia; Calderón, Oscar G; Caro, Cesar E; Cabrera-Granado, E; Antón, M A; Carreño, F

    2008-04-15

    We report a change from sub- to superluminal propagation upon increasing the modulation frequency of an amplitude-modulated 1,550 nm signal when propagating through highly doped erbium fibers pumped at 980 nm. We show that the interplay between the pump absorption and the pump-power broadening of the spectral hole induced by coherent population oscillations may drastically affect the fractional advancement or delay of the signal for the considered fibers.

  12. A redox responsive, fluorescent supramolecular metallohydrogel consists of nanofibers with single-molecule width

    KAUST Repository

    Zhang, Ye

    2013-04-03

    The integration of a tripeptide derivative, which is a versatile self-assembly motif, with a ruthenium(II)tris(bipyridine) complex affords the first supramolecular metallo-hydrogelator that not only self assembles in water to form a hydrogel but also exhibits gel-sol transition upon oxidation of the metal center. Surprisingly, the incorporation of the metal complex in the hydrogelator results in the nanofibers, formed by the self-assembly of the hydrogelator in water, to have the width of a single molecule of the hydrogelator. These results illustrate that metal complexes, besides being able to impart rich optical, electronic, redox, or magnetic properties to supramolecular hydrogels, also offer a unique geometrical control to prearrange the self-assembly motif prior to self-assembling. The use of metal complexes to modulate the dimensionality of intermolecular interactions may also help elucidate the interactions of the molecular nanofibers with other molecules, thus facilitating the development of supramolecular hydrogel materials for a wide range of applications. © 2013 American Chemical Society.

  13. Mechanical Engineering Safety Note: Analysis and Control of Hazards Associated with NIF Capacitor Module Events

    Energy Technology Data Exchange (ETDEWEB)

    Brereton, S

    2001-08-01

    The NIF capacitor module was reviewed with respect to pressure venting and shrapnel containment during failures. A modified module concept was proposed that would adequately vent the pressure, yet be effective at containing shrapnel. Two large vents are provided on each side of the module. These have fixed vent areas, and are immediately accessible for pressure venting at the beginning of a pressure transient. A shrapnel shield is located on the outside of each vent opening forming a chute. The chute contains a collimator. This increases the number of bounces that shrapnel must take on the way out, and directs the shrapnel to the trap beneath. The trap contains a depth of clear pine, sufficient to completely absorb the energy of even the most energetic fragment considered. Based on a review of the evidence from past capacitor failures at the FANTM facility at Sandia National Laboratory, Albuquerque, and additional theoretical estimates, the peak pressure generated in the module during explosive events was estimated to be less than 40 psig. This internal pressure in the FANTM module appears to be tolerable, as only minor damage to the module and to internal components was observed after events. The new module concept proposed here provides increased venting area, fully available at the initiation of an event. It is expected that even less damage would be observed if an event occurred in a module with this design. The module joints and connections were formally reviewed with respect to their tolerance to a brief internal pressure as high as 40 psig. With minor modifications that have been incorporated into the design, the module was shown to maintain its integrity during such events. Some of the calculations performed estimated the quantity of dielectric oil that could be involved in a capacitor failure. It was determined that a very small amount of the available oil would contribute to the explosive event, on the order of 500 g or less. This is a small fraction of

  14. METHOD OF DETERMINING THE START TIME OF INDUCTION MOTORS IN THE CONTROL OF RESISTOR-THYRISTOR MODULES

    Directory of Open Access Journals (Sweden)

    V.I. Lobov

    2015-08-01

    Full Text Available Purpose. An electric general-purpose drive with asynchronous motor is proposed. For motor control in stator and rotor, circuits used resistors and thyristors. These elements included together in various ways. This allows to get a variety of power converter circuit with resistor-thyristor modules. Methodology. Taking into account the technical requirements for industrial machinery developed an analytical method for determining the run-up controlled induction motor. Formed starting modes by changing the value of the equivalent resistor-thyristor modules. Using logic synthesis and function of thyristors switching to determine the equivalent value of resistor-thyristor modules. Scientific novelty. It lies in the fact that the proposed method of calculation to determine the run-up in the limited amount of transient current and torque of the motor. The total moment of inertia and the static moment of the drive do not have a significant impact on the maximum value of the transient electromagnetic torque. Most of these options affect the transition process, the oscillation frequency of the electromagnetic torque and the motor speed. Practical value. The method used for calculating allows to select the simplest laws of launch control actuator and apply open-loop control system without increasing the cost of the power converter, so it is of practical importance.

  15. Dosimetric advantages of intensity-modulated proton therapy for oropharyngeal cancer compared with intensity-modulated radiation: A case-matched control analysis.

    Science.gov (United States)

    Holliday, Emma B; Kocak-Uzel, Esengul; Feng, Lei; Thaker, Nikhil G; Blanchard, Pierre; Rosenthal, David I; Gunn, G Brandon; Garden, Adam S; Frank, Steven J

    2016-01-01

    A potential advantage of intensity-modulated proton therapy (IMPT) over intensity-modulated (photon) radiation therapy (IMRT) in the treatment of oropharyngeal carcinoma (OPC) is lower radiation dose to several critical structures involved in the development of nausea and vomiting, mucositis, and dysphagia. The purpose of this study was to quantify doses to critical structures for patients with OPC treated with IMPT and compare those with doses on IMRT plans generated for the same patients and with a matched cohort of patients actually treated with IMRT. In this study, 25 patients newly diagnosed with OPC were treated with IMPT between 2011 and 2012. Comparison IMRT plans were generated for these patients and for additional IMRT-treated controls extracted from a database of patients with OPC treated between 2000 and 2009. Cases were matched based on the following criteria, in order: unilateral vs bilateral therapy, tonsil vs base of tongue primary, T-category, N-category, concurrent chemotherapy, induction chemotherapy, smoking status, sex, and age. Results showed that the mean doses to the anterior and posterior oral cavity, hard palate, larynx, mandible, and esophagus were significantly lower with IMPT than with IMRT comparison plans generated for the same cohort, as were doses to several central nervous system structures involved in the nausea and vomiting response. Similar differences were found when comparing dose to organs at risks (OARs) between the IMPT cohort and the case-matched IMRT cohort. In conclusion, these findings suggest that patients with OPC treated with IMPT may experience fewer and less severe side effects during therapy. This may be the result of decreased beam path toxicities with IMPT due to lower doses to several dysphagia, odynophagia, and nausea and vomiting-associated OARs. Further study is needed to evaluate differences in long-term disease control and chronic toxicity between patients with OPC treated with IMPT in comparison to those

  16. Genetic selection for modulators of the MAP kinase and beta-catenin growth-control pathways in mammalian cells.

    Science.gov (United States)

    Wheatley, William; Yoo, Sanghee; Pierce, Michael; Rebentisch, Matthew; Endo, Mark; Peterson, Isaac; Stump, Mark; McCormack, Ken; Garcia-Guzman, Miguel; Kamb, Alexander

    2002-12-01

    Transdominant genetic selections can yield protein fragment and peptide modulators of specific biochemical pathways. In yeast, such screens have been highly successful in targeting the MAP (mitogen-activated protein) kinase growth-control pathway. We performed a similar type of selection aimed at recovery of modulators of the mammalian MAP kinase cascade. Two pathway activators were identified, fragments of the TrkB and Raf-1 kinases. In a second selection directed at the beta-catenin growth-control pathway, three different clones encoding cadherin fragments were recovered. In neither selection were peptide inhibitors observed. We conclude that some transdominant selections in mammalian cells can readily yield high-penetrance protein fragments, but may be less amenable to isolation of peptide inhibitors.

  17. Multicolor optical Nyquist pulse generation based on self-phase modulation without line-by-line control

    Science.gov (United States)

    Wang, Dong; Huo, Li; Jiang, Xiangyu; Lou, Caiyun

    2016-12-01

    Multicolor optical Nyquist pulse generation based on self-phase modulation without line-by-line control is proposed and experimental demonstrated. By 1.4-ps nearly chirp-free optical Gaussian pulse pumping of a high nonlinearity fiber, a 25-GHz spacing, flat-topped supercontinuum (SC) over 17.8 nm within 3.6 dB power variation at a modest pump power of 21.8 dBm is performed. As the phase of the central 90 tones is almost linear to the wavelength after dispersion compensation, spatial light modulator placed after SC for precise line-by-line control both of amplitude and phase can be replaced by conventional optical band-pass filter (OBPF). With an array of quasi-rectangular OBPFs, nearly transform-limited optical Nyquist pulses with a duty cycle of 5.5% on 4 wavelengths are achieved simultaneously.

  18. ANFIS-based estimation of PV module equivalent parameters: application to a stand-alone PV system with MPPT controller

    OpenAIRE

    KULAKSIZ, Ahmet Afşin

    2012-01-01

    The performance and system cost of photovoltaic (PV) systems can be improved by employing high-efficiency power conditioners with maximum power point tracking (MPPT) methods. Fast implementation and accurate operation of MPPT controllers can be realized by modeling the characteristics of PV modules, obtaining equivalent parameters. In this study, adaptive neuro-fuzzy inference systems (ANFISs) have been used to obtain 3 of the parameters in a single-diode model of PV cells, namely serie...

  19. Speed Sensorless Direct Torque Control of a PMSM Drive using Space Vector Modulation Based MRAS and Stator Resistance Estimator

    OpenAIRE

    A. Ameur; B. Mokhtari; N. Essounbouli; L. Mokrani

    2012-01-01

    This paper presents a speed sensorless direct torque control scheme using space vector modulation (DTC-SVM) for permanent magnet synchronous motor (PMSM) drive based a Model Reference Adaptive System (MRAS) algorithm and stator resistance estimator. The MRAS is utilized to estimate speed and stator resistance and compensate the effects of parameter variation on stator resistance, which makes flux and torque estimation more accurate and insensitive to parameter variation. ...

  20. Ag contact properties according to the front grid width and firing temperature for silicon solar cells.

    Science.gov (United States)

    Kim, Seongtak; Park, Sungeun; Kim, Young Do; Bae, Soohyun; Boo, Hyunpil; Kim, Hyunho; Lee, Kyung Dong; Tark, Sung Ju; Kim, Donghwan

    2014-10-01

    The effect of peak firing temperature and grid width on the contact properties between Ag metal and silicon (n+ emitter) was investigated for screen-printed silicon solar cells. We confirmed the factors that control the specific contact resistance as follows: (1) the Ag coverage fraction on the silicon surface, d(2) the thickness of the glass layer and (3) the etching depth on the n+ emitter region. The lowest specific contact resistance (8.27 mΩ x cm2) was obtained at the optimum firing temperature (720 degrees C). We also found that the grid width affected the contact quality of Ag paste because the contact width related to the absorbed heat of samples in RTP system. For this reason, when the grid width was further reduced, meaning more heat absorption, more Ag crystallites grew and the glass layer thickened. Light I-V results of a 6-inch silicon solar cell with minimum busbar width were similar to the PC1D simulation results. The efficiency was improved by 0.2% with the reduction of the busbar width.

  1. [Effects of urban river width on the temperature and humidity of nearby green belts in summer].

    Science.gov (United States)

    Ji, Peng; Zhu, Chun-Yang; Li, Shu-Hua

    2012-03-01

    As an important part of urban ecosystem, urban river plays a vital role in improving urban ecological environment. By the methods of small scale quantitative measurement, this paper analyzed the effects of seven urban rivers with different widths along the Third to Fifth Ring in Beijing on the air temperature and relative humidity of nearby green belts. The results showed that urban river width was the main factor affecting the temperature and humidity of nearby green belts. When the river had a width of 8 m, it had no effects in decreasing temperature but definite effects in increasing humidity; when the river width was 14-33 m, obvious effects were observed in decreasing temperature and increasing humidity; when the river had a width larger than 40 m, the effects in decreasing temperature and increasing humidity were significant and tended to be stable. There existed significant differences in the temperature and humidity between the green belts near the seven rivers and the corresponding controls. The critical width of urban river for the obvious effects in decreasing temperature and increasing humidity was 44 m. The regression equation of the temperature (x) and humidity (y) for the seven green belts nearby the urban rivers in summer was y = 173.191-3.247x, with the relative humidity increased by 1.0% when the air temperature decreased by about 0.3 degrees C.

  2. Disease Control After Reduced Volume Conformal and Intensity Modulated Radiation Therapy for Childhood Craniopharyngioma

    Energy Technology Data Exchange (ETDEWEB)

    Merchant, Thomas E., E-mail: thomas.merchant@stjude.org [St Jude Children' s Research Hospital, Radiological Sciences, Memphis, Tennessee (United States); Kun, Larry E.; Hua, Chia-Ho [St Jude Children' s Research Hospital, Radiological Sciences, Memphis, Tennessee (United States); Wu, Shengjie; Xiong, Xiaoping [St Jude Children' s Research Hospital, Biostatistics, Memphis, Tennessee (United States); Sanford, Robert A.; Boop, Frederick A. [Semmes Murphey Neurologic and Spine Institute, Neurosurgery, Memphis, Tennessee (United States)

    2013-03-15

    Purpose: To estimate the rate of disease control after conformal radiation therapy using reduced clinical target volume (CTV) margins and to determine factors that predict for tumor progression. Methods and Materials: Eighty-eight children (median age, 8.5 years; range, 3.2-17.6 years) received conformal or intensity modulated radiation therapy between 1998 and 2009. The study group included those prospectively treated from 1998 to 2003, using a 10-mm CTV, defined as the margin surrounding the solid and cystic tumor targeted to receive the prescription dose of 54 Gy. The CTV margin was subsequently reduced after 2003, yielding 2 groups of patients: those treated with a CTV margin greater than 5 mm (n=26) and those treated with a CTV margin less than or equal to 5 mm (n=62). Disease progression was estimated on the basis of additional variables including sex, race, extent of resection, tumor interventions, target volume margins, and frequency of weekly surveillance magnetic resonance (MR) imaging during radiation therapy. Median follow-up was 5 years. Results: There was no difference between progression-free survival rates based on CTV margins (>5 mm vs ≤5 mm) at 5 years (88.1% ± 6.3% vs 96.2% ± 4.4% [P=.6386]). There were no differences based on planning target volume (PTV) margins (or combined CTV plus PTV margins). The PTV was systematically reduced from 5 to 3 mm during the time period of the study. Factors predictive of superior progression-free survival included Caucasian race (P=.0175), no requirement for cerebrospinal fluid shunting (P=.0066), and number of surveillance imaging studies during treatment (P=.0216). Patients whose treatment protocol included a higher number of weekly surveillance MR imaging evaluations had a lower rate of tumor progression. Conclusions: These results suggest that targeted volume reductions for radiation therapy using smaller margins are feasible and safe but require careful monitoring. We are currently investigating

  3. Effect of integrated yoga module on personality of home guards in Bengaluru: A randomized control trial.

    Science.gov (United States)

    Amaranath, B; Nagendra, H R; Deshpande, Sudheer

    2016-03-01

    Home Guards Organization is an independent disciplined and uniformed body of volunteers. All categories of home guards (HGs), who work in the field, experience varied emotions and are required to cope with varied situations. Yoga practices may be helpful to master such emotions and should lead to improvement in personality. To study the efficacy of integrated yoga module (IYM) on personality (Gunās) (yogic personality measure) of HGs. Of 500 HGs who attended introductory lectures, 148 HGs of either gender, who satisfied the inclusion and exclusion criteria and who consented to participate in the study were randomly allocated to two groups. The yoga group (YG) practiced an IYM for 1 h daily, 6 days a week for 8 weeks along with their routine work. The control group (CG) remained on routine work. Personality was assessed before and after 8 weeks using the self-administered Vedic Personality Inventory. Baseline scores for all domains for both groups did not differ significantly (P > 0.05, Shapiro Wilk's test). Sattva score in YG significantly increased from 39.87 ± 2.02 to 47.14 ± 7.22, where as it decreased significantly from 43.66 ± 4.39 to 37.74 ± 10.26 in CG. Rajas score in YG significantly decreased from 29.15 ± 0.98 to 27.46 ± 4.38, where as it increased significantly from 28.60 ± 3.55 to 32.74 ± 5.37 in CG. Tamas score in YG significantly decreased from 30.98 ± 1.04 to 25.40 ± 5.11, where as it significantly increased from 27.74 ± 4.43 to 30.51 ± 5.50 in CG. Results indicate that IYM can profitably be suggested for HGs as a cost-effective means to help them cope with stressful situations. Copyright © 2016 Transdisciplinary University, Bangalore and World Ayurveda Foundation. Published by Elsevier B.V. All rights reserved.

  4. Mass spectrometric characterization of the selective androgen receptor modulator (SARM) YK-11 for doping control purposes.

    Science.gov (United States)

    Thevis, Mario; Piper, Thomas; Dib, Josef; Lagojda, Andreas; Kühne, Dirk; Packschies, Lars; Geyer, Hans; Schänzer, Wilhelm

    2017-07-30

    Selective androgen receptor modulators (SARMs) represent an emerging class of therapeutics targeting inter alia conditions referred to as cachexia and sarcopenia. Due to their anabolic properties, the use of SARMs is prohibited in sports as regulated by the World Anti-Doping Agency (WADA), and doping control laboratories test for these anabolic agents in blood and urine. In order to accomplish and maintain comprehensive test methods, the characterization of new drug candidates is critical for efficient sports drug testing. Hence, in the present study the mass spectrometric properties of the SARM YK-11 were investigated. YK-11 was synthesized according to literature data and three different stable-isotope-labeled analogs were prepared to support the mass spectrometric studies. Using high-resolution/high-accuracy mass spectrometry following electrospray ionization as well as electron ionization, the dissociation pathways of YK-11 were investigated, and characteristic features of its (product ion) mass spectra were elucidated. These studies were flanked by density functional theory (DFT) computation providing information on proton affinities of selected functional groups of the analyte. The steroidal SARM YK-11 was found to readily protonate under ESI conditions followed by substantial in-source dissociation processes eliminating methanol, acetic acid methyl ester, and/or ketene. DFT computation yielded energetically favored structures of the protonated species resulting from the aforementioned elimination processes particularly following protonation of the steroidal D-ring substituent. Underlying dissociation pathways were suggested, supported by stable-isotope labeling of the analyte, and diagnostic product ions for the steroidal nucleus and the D-ring substituent were identified. Further, trimethylsilylated YK-11 and its deuterated analogs were subjected to electron ionization high-resolution/high-accuracy mass spectrometry, complementing the dataset characterizing

  5. Quantum well saturable absorber mirror with electrical control of modulation depth

    DEFF Research Database (Denmark)

    Liu, Xiaomin; Rafailov, E.U.; Livshits, D.

    2010-01-01

    A saturable absorber mirror comprizing InGaAs/GaAs quantum wells incorporated into a p-i-n structure is demonstrated. Its modulation depth can be reduced from 4.25 % to 1.63 % by applying reverse bias voltage in the range 0–1 V.......A saturable absorber mirror comprizing InGaAs/GaAs quantum wells incorporated into a p-i-n structure is demonstrated. Its modulation depth can be reduced from 4.25 % to 1.63 % by applying reverse bias voltage in the range 0–1 V....

  6. Role of Modulators in Controlling the Colloidal Stability and Polydispersity of the UiO-66 Metal–Organic Framework

    Energy Technology Data Exchange (ETDEWEB)

    Morris, William; Wang, Shunzhi; Cho, David; Auyeung, Evelyn [Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, Illinois 60208, United States; Li, Peng; Farha, Omar K. [Department of Chemistry, King Abdulaziz University, Jeddah 21589, Saudi Arabia; Mirkin, Chad A. [Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, Illinois 60208, United States

    2017-04-07

    Nanoscale UiO-66 Zr6(OH)4O4(C8O4H4)6 has been synthesized with a series of carboxylic acid modulators, R-COOH (where R = H, CH3, CF3, and CHCl2). The phase purity and size of each MOF was confirmed by powder X-ray diffraction, BET surface area analysis, and scanning transmission electron microscopy (STEM). Size control of UiO-66 crystals from 20 nm to over 1 μm was achieved, and confirmed by STEM. The colloidal stability of each MOF was evaluated by dynamic light scattering and was found to be highly dependent on the modulator conditions utilized in the synthesis, with both lower pKa and higher acid concentration resulting in more stable structures. Furthermore, STEM was carried out on both colloidally stable samples and those that exhibited a large degree of aggregation, which allowed for visualization of the different degrees of dispersion of the samples. The use of modulators at higher concentrations and with lower pKas leads to the formation of more defects, as a consequence of terephthalic acid ligands being replaced by modulator molecules, thereby enhancing the colloidal stability of the UiO-66 nanoparticles. These findings could have a significant impact on nanoscale MOF material syntheses and applications, especially in the areas of catalysis and drug delivery.

  7. Novel Modulation Method for Multidirectional Matrix Converter

    Directory of Open Access Journals (Sweden)

    Saman Toosi

    2014-01-01

    Full Text Available This study presents a new modulation method for multidirectional matrix converter (MDMC, based on the direct duty ratio pulse width modulation (DDPWM. In this study, a new structure of MDMC has been proposed to control the power flow direction through the stand-alone battery based system and hybrid vehicle. The modulation method acts based on the average voltage over one switching period concept. Therefore, in order to determine the duty ratio for each switch, the instantaneous input voltages are captured and compared with triangular waveform continuously. By selecting the proper switching pattern and changing the slope of the carriers, the sinusoidal input current can be synthesized with high power factor and desired output voltage. The proposed system increases the discharging time of the battery by injecting the power to the system from the generator and battery at the same time. Thus, it makes the battery life longer and saves more energy. This paper also derived necessary equation for proposed modulation method as well as detail of analysis and modulation algorithm. The theoretical and modulation concepts presented have been verified in MATLAB simulation.

  8. Novel modulation method for multidirectional matrix converter.

    Science.gov (United States)

    Toosi, Saman; Misron, Norhisam; Hanamoto, Tsuyoshi; Bin Aris, Ishak; Radzi, Mohd Amran Mohd; Yamada, Hiroaki

    2014-01-01

    This study presents a new modulation method for multidirectional matrix converter (MDMC), based on the direct duty ratio pulse width modulation (DDPWM). In this study, a new structure of MDMC has been proposed to control the power flow direction through the stand-alone battery based system and hybrid vehicle. The modulation method acts based on the average voltage over one switching period concept. Therefore, in order to determine the duty ratio for each switch, the instantaneous input voltages are captured and compared with triangular waveform continuously. By selecting the proper switching pattern and changing the slope of the carriers, the sinusoidal input current can be synthesized with high power factor and desired output voltage. The proposed system increases the discharging time of the battery by injecting the power to the system from the generator and battery at the same time. Thus, it makes the battery life longer and saves more energy. This paper also derived necessary equation for proposed modulation method as well as detail of analysis and modulation algorithm. The theoretical and modulation concepts presented have been verified in MATLAB simulation.

  9. Unravelling the role of quantum interference in the weak-field laser phase modulation control of photofragment distributions

    DEFF Research Database (Denmark)

    García-Vela, Alberto; Henriksen, Niels Engholm

    2016-01-01

    The role played by quantum interference in the laser phase modulation coherent control of photofragment distributions in the weak-field regime is investigated in detail in this work. The specific application involves realistic wave packet calculations of the transient vibrational populations...... for a long time window are explained in terms of the mechanism of interference between overlapping resonances. A detailed description of how the interference mechanism affects the magnitude and the time window of the phase control effects is also provided. In the light of the results, the conditions...

  10. FPGA-based phase control of acousto-optic modulator Fourier synthesis system through gradient descent phase-locking algorithm.

    Science.gov (United States)

    Underwood, Kenneth J; Jones, Andrew M; Gopinath, Juliet T

    2015-06-20

    We present a new application of the stochastic parallel gradient descent (SPGD) algorithm to fast active phase control in a Fourier synthesis system. Pulses (4.9 ns) with an 80 MHz repetition rate are generated by feedback from a single phase-sensitive metric. Phase control is applied via fast current modulation of a tapered amplifier using an SPGD algorithm realized on a field-programmable gate array (FPGA). The waveforms are maintained by constant active feedback from the FPGA. We also discuss the extension of this technique to many more semiconductor laser emitters in a diode laser array.

  11. Crack Width Analysis of Steel Fiber Reinforced Concrete Elements

    Directory of Open Access Journals (Sweden)

    Darius Ulbinas

    2011-04-01

    Full Text Available The article investigates the effectiveness of steel fiber reinforcement in RC concrete members in regard to ordinary reinforcement. The advantages and disadvantages of different shapes of steel fibers are discussed. The algorithm for calculating crack width based on EC2 and Rilem methodologies is presented. A comparison of theoretical and experimental crack widths has been performed. The relative errors of crack width predictions at different load levels were defined.Article in Lithuanian

  12. The significance of biometric parameters in determining anterior teeth width

    Directory of Open Access Journals (Sweden)

    Strajnić Ljiljana

    2013-01-01

    Full Text Available Background/Aim. An important element of prosthetic treatment of edentulous patients is selecting the size of anterior artificial teeth that will restore the natural harmony of one’s dentolabial structure as well as the whole face. The main objective of this study was to determine the correlation between the inner canthal distance (ICD and interalar width (IAW on one side and the width of both central incisors (CIW, the width of central and lateral incisors (CLIW, the width of anterior teeth (ATW, the width between the canine cusps (CCW, which may be useful in clinical practice. Methods. A total of 89 subjects comprising 23 male and 66 female were studied. Their age ranged from 19 to 34 years with the mean of 25 years. Only the subjects with the preserved natural dentition were included in the sample. All facial and intraoral tooth measurements were made with a Boley Gauge (Buffalo Dental Manufacturing Co., Brooklyn NY, USA having a resolution of 0.1mm. Results. A moderate correlation was established between the interalar width and combined width of anterior teeth and canine cusp width (r = 0.439, r = 0.374. A low correlation was established between the inner canthal distance and the width of anterior teeth and canine cusp width (r = 0.335, r = 0.303. The differences between the two genders were highly significant for all the parameters (p < 0.01. The measured facial distances and width of anterior teeth were higher in men than in women. Conclusion. The results of this study suggest that the examined interalar width and inner canthal distance cannot be considered reliable guidelines in the selection of artificial upper anterior teeth. However, they may be used as a useful additional factor combined with other methods for objective tooth selection. The final decision should be made while working on dentures fitting models with the patient’s consent.

  13. Oxytocin Modulates Amygdala, Insula, and Inferior Frontal Gyrus Responses to Infant Crying : A Randomized Controlled Trial

    NARCIS (Netherlands)

    Riem, Madelon M. E.; Bakermans-Kranenburg, Marian J.; Pieper, Suzanne; Tops, Mattie; Boksem, Maarten A. S.; Vermeiren, Robert R. J. M.; van IJzendoorn, Marinus H.; Rombouts, Serge A. R. B.

    2011-01-01

    Background: Oxytocin facilitates parental caregiving and mother-infant bonding and might be involved in responses to infant crying. Infant crying provides information about the physical status and mood of the infant and elicits parental proximity and caregiving. Oxytocin might modulate the

  14. Distributed control of PV strings with module integrated converters in presence of a central MPPT

    DEFF Research Database (Denmark)

    Sera, Dezso; Mathe, Laszlo; Blaabjerg, Frede

    2014-01-01

    to be a good solution for such cases, having the potential to increase the yield with as high as 25%, although there is the added cost of the MICs. A cost-effective solution could be to limit the installation of MICs only to the affected modules. However, this solution carries some new challenges...

  15. Controlled Study on the Effectiveness of Multimedia Learning Modules for Teaching Mechanics

    Science.gov (United States)

    Sadaghiani, Homeyra R.

    2012-01-01

    We have investigated the impact of using multimedia learning modules (MLM) on the learning of students enrolled in introductory physics courses at California State Polytechnic University, Pomona. One hundred fifty-nine students were randomly registered in two sections of an introductory mechanics course, one of which featured the MLMs. Both…

  16. Distribution of resonance widths and dynamics of continuum coupling.

    Science.gov (United States)

    Celardo, G L; Auerbach, N; Izrailev, F M; Zelevinsky, V G

    2011-01-28

    We analyze the statistics of resonance widths in a many-body Fermi system with open decay channels. Depending on the strength of continuum coupling, such a system reveals growing deviations from the standard chi-square (Porter-Thomas) width distribution. The deviations emerge from the process of increasing interaction of intrinsic states through common decay channels; in the limit of perfect coupling this process leads to the superradiance phase transition. The width distribution depends also on the intrinsic dynamics (chaotic versus regular). The results presented here are important for understanding the recent experimental data concerning the width distribution for neutron resonances in nuclei.

  17. A preliminary comparison of myoelectric and cyclic control of an implanted neuroprosthesis to modulate gait speed in incomplete SCI.

    Science.gov (United States)

    Lombardo, Lisa M; Bailey, Stephanie N; Foglyano, Kevin M; Miller, Michael E; Pinault, Gilles; Triolo, Ronald J

    2015-01-01

    Explore whether electromyography (EMG) control of electrical stimulation for walking after incomplete spinal cord injury (SCI) can affect ability to modulate speed and alter gait spatial-temporal parameters compared to cyclic repetition of pre-programmed stimulation. Single case study with subject acting as own concurrent control. Setting Hospital-based biomechanics laboratory. Single subject with C6 AIS D SCI using an implanted neuroprosthesis for walking. Interventions Lower extremity muscle activation via an implanted system with two different control methods: (1) pre-programmed pattern of stimulation, and (2) EMG-controlled stimulation based on signals from the gastrocnemius and quadriceps. Gait speed, distance, and subjective rating of difficulty during 2-minute walks. Range of walking speeds and associated cadences, stride lengths, stride times, and double support times during quantitative gait analysis. EMG control resulted in statistically significant increases in both walking speed and distance (P < 0.001) over cyclic stimulation during 2-minute walks. Maximum walking speed with EMG control (0.48 m/second) was significantly (P < 0.001) faster than the fastest automatic pattern (0.39 m/second), with increased cadence and decreased stride and double support times (P < 0.000) but no change in stride length (z = -0.085; P = 0.932). The slowest walking with EMG control (0.25 m/second) was virtually indistinguishable from the slowest with automatic cycling (z = -0.239; P = 0.811). EMG control can increase the ability to modulate comfortable walking speed over pre-programmed cyclic stimulation. While control methods did not differ at the lowest speed, EMG-triggered stimulation allowed significantly faster walking than cyclic stimulation. The expanded range of available walking speeds could permit users to better avoid obstacles and naturally adapt to various environments. Further research is required to definitively determine the robustness, generalizability, and

  18. Invariantly propagating dissolution fingers in finite-width systems

    Science.gov (United States)

    Dutka, Filip; Szymczak, Piotr

    2016-04-01

    Dissolution fingers are formed in porous medium due to positive feedback between transport of reactant and chemical reactions [1-4]. We investigate two-dimensional semi-infinite systems, with constant width W in one direction. In numerical simulations we solve the Darcy flow problem combined with advection-dispersion-reaction equation for the solute transport to track the evolving shapes of the fingers and concentration of reactant in the system. We find the stationary, invariantly propagating finger shapes for different widths of the system, flow and reaction rates. Shape of the reaction front, turns out to be controlled by two dimensionless numbers - the (width-based) Péclet number PeW = vW/Dφ0 and Damköhler number DaW = ksW/v, where k is the reaction rate, s - specific reactive surface area, v - characteristic flow rate, D - diffusion coefficient of the solute, and φ0 - initial porosity of the rock matrix. Depending on PeW and DaW stationary shapes can be divided into seperate classes, e.g. parabolic-like and needle-like structures, which can be inferred from theoretical predictions. In addition we determine velocity of propagating fingers in time and concentration of reagent in the system. Our simulations are compared with natural forms (solution pipes). P. Ortoleva, J. Chadam, E. Merino, and A. Sen, Geochemical self-organization II: the reactive-infiltration instability, Am. J. Sci, 287, 1008-1040 (1987). M. L. Hoefner, and H. S. Fogler. Pore evolution and channel formation during flow and reaction in porous media, AIChE Journal 34, 45-54 (1988). C. E. Cohen, D. Ding, M. Quintard, and B. Bazin, From pore scale to wellbore scale: impact of geometry on wormhole growth in carbonate acidization, Chemical Engineering Science 63, 3088-3099 (2008). P. Szymczak and A. J. C. Ladd, Reactive-infiltration nstabilities in rocks. Part II: Dissolution of a porous matrix, J. Fluid Mech. 738, 591-630 (2014).

  19. Tunable line width all solid state double spectral line sodium beacon laser

    Science.gov (United States)

    Lu, Yanhua; Zhang, Lei; Xu, Xiafei; Ren, Huaijin; Wei, Bin; Yuan, Liao; Gong, Shenggang; Li, Tao; Gu, Jingliang; Wan, Min; Fan, Guobin

    2017-10-01

    We developed a tunable-line-width 101 W average-power all-solid-state 589nm double spectral line sodium beacon laser. The laser was based on the technical route of 1064nm and 1319nm Nd:YAG laser extra cavity sum frequency generation. The laser contained two spectral lines: 589.1591 nm and 589.1571 nm. The former line was matched to the sodium D2a absorption line with the average power of 81W, while the other line was matched to the sodium D2b absorption line with the average power of 20W. The beam quality of the two spectral line lasers was both less than 1.3. The two lasers were polarized-combined to transmit coaxially. The initial line width of the laser was about 0.3GHz, which was in the comb-like discrete structure of about three longitudinal modes. We used a white noise generator to modulate the 1064nm single frequency seed laser in frequency domain. The line width's tunability was accomplished by tuning the driving power of the white noise generator. The final line width tuning range of the 589nm laser was 0.3GHz to 1.1GHz.

  20. Control of Mycosphaerella graminicola on wheat seedlings by medical drugs known to modulate the activity of ATP-binding cassette transporters

    NARCIS (Netherlands)

    Roohparvar, R.; Huser, A.; Zwiers, L.H.; Waard, de M.A.

    2007-01-01

    Medical drugs known to modulate the activity of human ATP-binding cassette (ABC) transporter proteins (modulators) were tested for the ability to potentiate the activity of the azole fungicide cyproconazole against in vitro growth of Mycosphaerella graminicola and to control disease development due

  1. Relationship between red cell distribution width and early renal injury in patients with gestational diabetes mellitus.

    Science.gov (United States)

    Cheng, Dong; Zhao, Jiangtao; Jian, Liguo; Ding, Tongbin; Liu, Shichao

    2016-09-01

    Previous studies found that red cell distribution width was related to adverse cardiovascular events. However, few studies reported the relationship between red cell distribution width and early-stage renal injury in pregnant women with gestational diabetes mellitus. Using a cross-sectional design, 334 pregnant women with gestational diabetes mellitus were enrolled according to the criterion of inclusion and exclusion. Demographic and clinical examination data were collected. Depended on the urine albumin, study population were divided into case group (n = 118) and control group (n = 216). Compared with control group, the case group tend to be higher red cell distribution width level (13.6 ± 0.9 vs.12.5 ± 0.6, p gestational diabetes mellitus patients. The elevated red cell distribution width level might be a predictor of early-stage renal injury in pregnant women with gestational diabetes mellitus. As an easy and routine examination index, red cell distribution width may provide better clinical guidance when combined with other important indices.

  2. Broadband photonic microwave phase shifter based on controlling two RF modulation sidebands via a Fourier-domain optical processor.

    Science.gov (United States)

    Yang, J; Chan, E H W; Wang, X; Feng, X; Guan, B

    2015-05-04

    An all-optical photonic microwave phase shifter that can realize a continuous 360° phase shift over a wide frequency range is presented. It is based on the new concept of controlling the amplitude and phase of the two RF modulation sidebands via a Fourier-domain optical processor. The operating frequency range of the phase shifter is largely increased compared to the previously reported Fourier-domain optical processor based phase shifter that uses only one RF modulation sideband. This is due to the extension of the lower RF operating frequency by designing the amplitude and phase of one of the RF modulation sidebands while the other sideband is designed to realize the required RF signal phase shift. The two-sideband amplitude-and-phase-control based photonic microwave phase shifter has a simple structure as it only requires a single laser source, a phase modulator, a Fourier-domain optical processor and a single photodetector. Investigation on the bandwidth limitation problem in the conventional Fourier-domain optical processor based phase shifter is presented. Comparisons between the measured phase shifter output RF amplitude and phase responses with theory, which show excellent agreement, are also presented for the first time. Experimental results demonstrate the full -180° to + 180° phase shift with little RF signal amplitude variation of less than 3 dB and with a phase deviation of less than 4° over a 7.5 GHz to 26.5 GHz frequency range, and the phase shifter exhibits a long term stable performance.

  3. C5 palsy after cervical laminectomy and fusion: does width of laminectomy matter?

    Science.gov (United States)

    Klement, Mitchell R; Kleeman, Lindsay T; Blizzard, Daniel J; Gallizzi, Michael A; Eure, Megan; Brown, Christopher R

    2016-04-01

    A common complication of cervical laminectomy and fusion with instrumentation (CLFI) is development of postoperative C5 nerve palsy. A proposed etiology is excess nerve tension from posterior drift of the spinal cord after decompression. We hypothesize that laminectomy width will be significantly increased in patients with C5 palsy and will correlate with palsy severity. The purposes of this study were to evaluate laminectomy width as a risk factor for C5 palsy and to assess correlation with palsy severity. This is a retrospective, single-institution clinical study. Patient population included all patients with cervical spondylotic myelopathy who underwent CLFI between 2007 and 2014 by a single surgeon. Patients who underwent CLFI for trauma, infection, or tumor or had previous or circumferential cervical surgery were excluded. All patients with a new C5 palsy received a postoperative magnetic resonance imaging. An additional computed tomography (CT) scan was ordered to assess hardware. All control patients received a CT scan at 6 months postoperatively to evaluate fusion. The association between width of laminectomy and development of postopeative C5 palsy was measured. Patient comorbidities including obesity, smoking history, and diabetes were recorded in addition to preopertaive and postoperative deltoid and biceps motor strength. Sagittal alignment was measured with C2-C7 Cobb angle preopertaive and postoperative radiographs. The width of laminectomy was measured in a blinded fashion on the postoperative CT scan by two observers. Seventeen patients with C5 nerve palsy and 12 controls were identified. There were no baseline differences in age, sex, diabetes, smoking history, number of surgical levels, or sagittal alignment. Body mass index was significantly higher in the control cohort. There was no significant increase in the C3-C7 laminectomy width in patients with postoperative C5 palsy. The width of laminectomy measurments were highly similar between the two

  4. Using nonlinearity and spatiotemporal property modulation to control effective structural properties: dynamic rods

    DEFF Research Database (Denmark)

    Thomsen, Jon Juel; Blekhman, Iliya I.

    2007-01-01

    the effective propagation speed of long waves by varying the amplitude of a superimposed high-frequency standing wave. It should be possible to change most properties related to structural stiffness, energy dissipation, and equilibrium states this way, by exploiting the general effects of stiffening, biasing......, and smoothening that characterize mechanically high-frequency excited structures. This work explores fundamental issues for spatiotemporally modulated nonlinear materials. First the effective stress-strain relation of a generally nonlinear material with a prescribed HF strain field is derived, discussed......, and exemplified. Then simple approximate analytical expressions are derived for the effective wave speed and natural frequencies for one-dimensional wave propagation in a nonlinear elastic rod, where the spatiotemporal modulation is imposed as a high-frequency standing wave, supposed to be given. Finally the more...

  5. A compact nanosecond pulse modulator

    Science.gov (United States)

    Sha, Jizhang; Xue, Jianchao; Qiang, Bohan

    Two circuits of nanosecond pulse modulator which generate two different width rectangular pulses respectively are described. The basic configuration of the modulator is the Marx circuit, in which avalanche transistors are used as switching devices. In order to obtain the rectangular pulses a pulse-forming network (PFN) is introduced and fitted into the Marx. A multi-parallel arrangement of the Marx is used to satisfy the broad pulse requirement. Experiments have shown that the two different width rectangular pulses which have 130 V amplitudes and 30 and 200 ns widths respectively can be obtained at a 50 ohms load. The two pulses have steep front edges (3.6 ns and 10 ns respectively) and flat tops with less than + or - 5 percent ripples. Therefore, the modulator can meet the requirements of the nanosecond pulse radar.

  6. High Performance Low Cost Digitally Controlled Power Conversion Technology

    DEFF Research Database (Denmark)

    Jakobsen, Lars Tønnes

    2008-01-01

    suited for digital control schemes involving multiple control loops such as digital control of a switch-mode power supply with several converter stages. Customised digital control solutions implemented in application specific integrated circuits are the best solution for high bandwidth digital control......Digital control of switch-mode power supplies and converters has within the last decade evolved from being an academic subject to an emerging market in the power electronics industry. This development has been pushed mainly by the computer industry that is looking towards digital power management...... of non-isolated DC-DC converters. A customised digital control solution for a voltage mode control scheme should include a digital pulse width modulator which can generate a pulse width modulated signal with high switching frequency and high resolution, a digital compensator with a short execution time...

  7. Quality control of roll-to-roll processed polymer solar modules by complementary imaging methods

    DEFF Research Database (Denmark)

    Rösch, R.; Krebs, Frederik C; Tanenbaum, D.M.

    2012-01-01

    ), electroluminescence (ELI) and photoluminescence/reflection imaging (PLI/RI) complemented by optical imaging (OI). The combination of all high resolution images allowed us to allocate the origin of processing errors to a specific deposition process, i.e. the insufficient coverage of an electrode interlayer....... The investigation can be divided into a fast DLIT overview of the module and a successive more detailed analysis of the suspicious region by all imaging methods....

  8. A water pumping control system with a programmable logic controller (PLC) and industrial wireless modules for industrial plants--an experimental setup.

    Science.gov (United States)

    Bayindir, Ramazan; Cetinceviz, Yucel

    2011-04-01

    This paper describes a water pumping control system that is designed for production plants and implemented in an experimental setup in a laboratory. These plants contain harsh environments in which chemicals, vibrations or moving parts exist that could potentially damage the cabling or wires that are part of the control system. Furthermore, the data has to be transferred over paths that are accessible to the public. The control systems that it uses are a programmable logic controller (PLC) and industrial wireless local area network (IWLAN) technologies. It is implemented by a PLC, an communication processor (CP), two IWLAN modules, and a distributed input/output (I/O) module, as well as the water pump and sensors. Our system communication is based on an Industrial Ethernet and uses the standard Transport Control Protocol/Internet Protocol for parameterisation, configuration and diagnostics. The main function of the PLC is to send a digital signal to the water pump to turn it on or off, based on the tank level, using a pressure transmitter and inputs from limit switches that indicate the level of the water in the tank. This paper aims to provide a convenient solution in process plants where cabling is not possible. It also has lower installation and maintenance cost, provides reliable operation, and robust and flexible construction, suitable for industrial applications. Copyright © 2010 ISA. Published by Elsevier Ltd. All rights reserved.

  9. Modulation control over ultrasound-mediated gene delivery: evaluating the importance of standing waves.

    Science.gov (United States)

    Hassan, Mariame A; Buldakov, Mikhail A; Ogawa, Ryohei; Zhao, Qing-Li; Furusawa, Yukihiro; Kudo, Nobuki; Kondo, Takashi; Riesz, Peter

    2010-01-04

    Low modulation frequencies from 0.5 to 100Hz were shown to alter the characteristics of the ultrasound field producing solution agitation (5Hz; region of standing waves establishment) (Buldakov et al., Ultrason. Sonochem., 2009). In this study, the same conditions were used to depict the changes in exogenous DNA delivery in these regions. The luciferase expression data revealed that lower modulations were more capable of enhancing delivery at the expense of viability. On the contrary, the viability was conserved at higher modulations whereas delivery was found to be null. Cavitational activity and acoustic streaming were the effecters beyond the observed pattern and delivery enhancement was shown to be mediated mainly through sonopermeation. To promote transfection, the addition of calcium ions or an echo contrast agent (Levovist((R))) was proposed. Depending on the mechanism involved in each approach, differential enhancement was observed in both regions and at the interim zone (5Hz). In both cases, enhancement in standing waves field was significant reaching 16.0 and 3.3 folds increase, respectively. Therefore, it is concluded that although the establishment of standing waves is not the only prerequisite for high transfection rates, yet, it is a key element in optimization when other factors such as proximity and cavitation are considered.

  10. Widths of narrow mesons made from heavy quarks

    CERN Document Server

    Farrar, Glennys R S; Okun, Lev Borisovich; Shifman, M A; Voloshin, M B; Zakharov, V I

    1977-01-01

    Presents predictions for the electronic widths of neutral vector mesons made from heavy quarks. Relying principally on dispersion relations and asymptotic freedom of QCD, these results are quite model-independent. Photonic and total hadronic widths of C-even mesons are also discussed. (6 refs).

  11. A design aid for determining width of filter strips

    Science.gov (United States)

    M.G. Dosskey; M.J. Helmers; D.E. Eisenhauer

    2008-01-01

    watershed planners need a tool for determining width of filter strips that is accurate enough for developing cost-effective site designs and easy enough to use for making quick determinations on a large number and variety of sites.This study employed the process-based Vegetative Filter Strip Model to evaluate the relationship between filter strip width and trapping...

  12. Comparison of arch width changes following orthodontic treatment ...

    African Journals Online (AJOL)

    Comparison of arch width changes following orthodontic treatment with and without extraction using three-dimensional models. ... Conclusion: Extraction treatment mechanics did not cause narrow dental arches, but nonextraction treatment increased arch width in all 3 measurements. Treatments with only upper arch ...

  13. Stream water responses to timber harvest: Riparian buffer width effectiveness

    Science.gov (United States)

    Barton D. Clinton

    2011-01-01

    Vegetated riparian buffers are critical for protecting aquatic and terrestrial processes and habitats in southern Appalachian ecosystems. In this case study, we examined the effect of riparian buffer width on stream water quality following upland forest management activities in four headwater catchments. Three riparian buffer widths were delineated prior to cutting; 0m...

  14. Crack widths in concrete with fibers and main reinforcement

    DEFF Research Database (Denmark)

    Christensen, Frede; Ulfkjær, Jens Peder; Brincker, Rune

    The main object of the research work presented in this paper is to establish design tools for concrete structures where main reinforcement is combined with addition of short discrete steel fibers. The work is concerned with calculating and measuring crack widths in structural elements subjected...... to bending load. Thus, the aim of the work is to enable engineers to calculate crack widths for flexural concrete members and analyze how different combinations of amounts of fibers and amounts of main reinforcement can meet a given maximum crack width requirement. A mathematical model including...... the ductility of the fiber reinforced concrete (FRC) is set up and experimental work is conducted in order to verify the crack width model. The ductility of the FRC is taken into account by using the stress crack width relation. The constitutive model for the FRC is based on the idea that the initial part...

  15. Advanced Control Strategies of Induction Machine: Field Oriented Control, Direct Torque Control and Model Predictive Control

    Directory of Open Access Journals (Sweden)

    Fengxiang Wang

    2018-01-01

    Full Text Available Field oriented control (FOC, direct torque control (DTC and finite set model predictive control (FS-MPC are different strategies for high performance electrical drive systems. FOC uses linear controllers and pulse width modulation (PWM to control the fundamental components of the load voltages. On the other hand, DTC and FS-MPC are nonlinear strategies that generate directly the voltage vectors in the absence of a modulator. This paper presents all three methods starting from theoretic operating principles, control structures and implementation. Experimental assessment is performed to discuss their advantages and limitations in detail. As main conclusions of this work, it is affirmed that different strategies have their own merits and all meet the requirements of modern high performance drives.

  16. Counterfactual Reasoning for Regretted Situations Involving Controllable Versus Uncontrollable Events: The Modulating Role of Contingent Self-Esteem

    Science.gov (United States)

    Wilkinson, Meredith R.; Ball, Linden J.; Alford, David

    2015-01-01

    We report a study that examined the modulating impact of contingent self-esteem on regret intensity for regretted outcomes associated with controllable versus uncontrollable events. The Contingent Self-Esteem Scale (e.g., Kernis & Goldman, 2006) was used to assess the extent to which a person’s sense of self-worth is based on self and others’ expectations. We found that there was an influence of self-esteem contingency for controllable but not for uncontrollable regret types. For controllable regret types individuals with a high contingent (i.e., unstable) self-esteem reported greater regret intensity than those with a low contingent (i.e., stable) self-esteem. We interpret this finding as reflecting a functional and adaptive role of high contingent self-esteem in terms of mobilizing the application of counterfactual reasoning and planning mechanisms that can enable personal expectations to be achieved in the future. PMID:25883697

  17. A unified analysis and design procedure for a standardized control module for dc-dc switching regulators

    Science.gov (United States)

    Lee, F. C.; Yu, Y.; Mahmoud, M. F.

    1980-01-01

    Three basic switching regulators: buck, boost, and buck/boost, employing a multi-loop control module (SCM) were characterized by a common small signal block diagram. Employing the unified model, regulator performances such as stability, audiosusceptibility, output impedance and step load transient are analyzed and key performance indexes are expressed in simple analytical forms. More importantly, the performance characteristics of all three regulators are shown to enjoy common properties due to the unique SCM control scheme which nullifies the positive zero and provides adaptive compensation to the moving poles of the boost and buck/boost converters. This allows a simple unified design procedure to be devised for selecting the key SCM control parameters for an arbitrarily given power stage configuration and parameter values, such that all regulator performance specifications can be met and optimized concurrently in a single design attempt.

  18. Dynamic cosine-Gauss plasmonic beam through phase control.

    Science.gov (United States)

    Xiao, Kai; Wei, Shibiao; Min, Changjun; Yuan, Guanghui; Zhu, S W; Lei, T; Yuan, X-C

    2014-06-02

    We carry out an approach to dynamic manipulation of a nondiffracting cosine-Gauss plasmonic beam (CGPB) illuminated with an incident phase modulation within nanostructures by a spatial light modulator (SLM). By changing the hologram addressed on the SLM, dynamic control on the lobe width and the propagating direction of the CGPB is experimentally verified. Finally, we demonstrate an application example of this dynamic CGPB in routing optical signals to multichannel subwavelength wave guides through numerical simulation.

  19. SCALE: A modular code system for performing standardized computer analyses for licensing evaluation. Control modules -- Volume 1, Revision 4

    Energy Technology Data Exchange (ETDEWEB)

    Landers, N.F.; Petrie, L.M.; Knight, J.R. [Oak Ridge National Lab., TN (United States)] [and others

    1995-04-01

    SCALE--a modular code system for Standardized Computer Analyses Licensing Evaluation--has been developed by Oak Ridge National Laboratory at the request of the US Nuclear Regulatory Commission. The SCALE system utilizes well-established computer codes and methods within standard analysis sequences that (1) allow an input format designed for the occasional user and/or novice, (2) automate the data processing and coupling between modules, and (3) provide accurate and reliable results. System development has been directed at problem-dependent cross-section processing and analysis of criticality safety, shielding, heat transfer, and depletion/decay problems. Since the initial release of SCALE in 1980, the code system has been heavily used for evaluation of nuclear fuel facility and package designs. This revision documents Version 4.2 of the system. This manual is divided into three volumes: Volume 1--for the control module documentation, Volume 2--for the functional module documentation, and Volume 3 for the documentation of the data libraries and subroutine libraries.

  20. Plaque accumulation and Streptococcus mutans levels around self-ligating bracket clips and elastomeric modules: A randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Dhaval Fadia

    2015-01-01

    Full Text Available Aim: To determine the effect of two different ligating systems that is, elastomeric modules and self-ligating (SL bracket systems (Smartclip - 3M Unitek with respect to harboring bacterial plaque in fixed orthodontic treatment. Objectives: To assess, evaluate, and compare the amount of plaque accumulation and Streptococcus mutans colonization around elastomeric ligation and SL clips in the smart clip appliance. Materials and Methods: A total of 111 orthodontic patients scheduled for fixed orthodontic treatments were selected for this split maxillary arch study. All the patients were bonded with smart-clip (3M Unitek SL brackets, and the wire was placed into the bracket slots, on the randomly selected hemi arch, elastomeric modules were placed for the study to be conducted. Microbial and periodontal plaque accumulation was recorded at 3-time intervals post ligation. Plaque index-by Silness and Loe, modified Quigely Hein index, bleeding on probing were evaluated, and biofilm was collected from the tooth surface after 30 days and placed in petri dishes containing Mitis Salivarius agar for bacterial culturing. Result: It was observed that the side where ligation was done with elastomeric modules accumulated more plaque and increase in S. mutans colony forming units as compared to the side without external ligation (P < 0.05. Conclusion: Reduced bacterial colonization and better plaque control was seen with SL orthodontic bracket appliance system as compared to conventional ligation method.

  1. Investigation of Mean Platelet Volume, Platelet Distribution Width and Erythrocyte Distribution Width in Patients with Hepatitis B Virus Infection

    Directory of Open Access Journals (Sweden)

    Kazım KIRATLI

    2017-12-01

    Full Text Available Objective: Hepatitis B virus (HBV infection is an important public health issue all over the world, and it has a high morbidity and mortality rates caused by chronic liver disease. Liver biopsy is the primary procedure for evaluating the fibrosis grade. Recently, non-invasive methods are used to predict liver histology. Complete blood count (CBC is one of the most needed and used laboratory tests in clinics. CBC parameters have been used in various studies to estimate the severity of the disease and the risk of mortality. In the present study, we aimed to determine the relationship of HBV infection with mean platelet volume (MPV, platelet distribution width (PDW and red cell distribution width (RDW. Materials and Methods: Two hundred fifty-nine hepatitis B surface antigen (HBsAg-positive patients, who attended the Infectious Diseases outpatient Clinic at Van Military Hospital between October 2013 and December 2014, were included in the study group. A total of 245 food handlers with similar socio-demographic characteristics with the study group, who applied at the same period, formed the control group. HBsAg-positive patients were studied in two groups as chronic active hepatitis and inactive carriers according to their follow-up. CBC results of the patients and the healthy controls were screened from the hospital information system and they were evaluated retrospectively. Results: The average platelet count in HBsAg-positive patients and controls was 262.59±62.13x103/mm3 and 245.28±60.78x103/mm3, respectively and the difference between the groups was statistically significant (p=0.002. There was also statistically significant difference in RDW values between the two groups. The average RDW was 12.14±1.05 in HBV group, while it was 12.49±1.28 in control group (p=0.001. On the other hand, no significant difference was observed in PDW and MPV between the groups. Conclusion: It is thought that simple, inexpensive and routinely used platelet and

  2. Balance measures for determining optimal caliper width in propensity score matching: A simulation study

    NARCIS (Netherlands)

    Ali, M. Sanni; Groenwold, R.H.H.; Belitser, Svetlana V.; Pestman, Wiebe R.; Hoes, Arno W.; Roes, Kit C.B.; Boer, Ade; Klungel, Olaf H.

    2013-01-01

    Background: When estimating the effects of exposure in observational data, propensity score (PS) methods can be used to control for confounding. When PS matching is used, often a pre-specified caliper width is applied. A crucial part of this matching approach is assessment of how close the

  3. Demonstration of EDFA Cognitive Gain Control via GMPLS for Mixed Modulation Formats in Heterogeneous Optical Networks

    DEFF Research Database (Denmark)

    Oliveira, Juliano R.; Caballero Jambrina, Antonio; Magalhães, Eduardo

    2013-01-01

    We demonstrate cognitive gain control for EDFA operation in real-time GMPLS controlled heterogeneous optical testbed with 10G/100G/200G/400G lightpaths. Cognitive control maintains the network BER below FEC-limit for up to 6 dB of induced attenuation penalty.......We demonstrate cognitive gain control for EDFA operation in real-time GMPLS controlled heterogeneous optical testbed with 10G/100G/200G/400G lightpaths. Cognitive control maintains the network BER below FEC-limit for up to 6 dB of induced attenuation penalty....

  4. Dual-bath Plating of Composition Modulated Alloys (CMA) based on a newly developed Computer Controlled Plating System

    DEFF Research Database (Denmark)

    Tang, Peter Torben; Leisner, Peter; Møller, Per

    1994-01-01

    of a computer controlled plating system for producing large scale CMA-coatings. Employing a dual-bath technique, multilayered materials with more than 1000 alternating layers have been manufactured and investigated. The thickness of each layer ranges from 25 nm to several microns. The characterisation results......Composition Modulated Alloys (CMA) are attracting ever increasing interests, as new and fascinating appli-cations are reported. Until recently, producing these multilayered coatings have been difficult, particularly for larger samples. This presentation will explain the design, use and purpose...

  5. A low noise high efficiency buck DC-DC converter with sigma—delta modulation

    Science.gov (United States)

    Shujiang, Cai; Changming, Pi; Wei, Yan; Wenhong, Li

    2011-07-01

    Some research efforts to improve the efficiency and noise performance of buck DC—DC converters are explored. A carefully designed power MOSFET driver, including a dead time controller, discontinuous current mode (DCM) controller and gate width controller, is proposed to improve efficiency. Instead of PWM modulation, sigma-delta modulation is introduced into the feedback loop of the converter to move out the clock-referred harmonic spike. The proposed converter has been designed and fabricated by a 0.35 μm CMOS process. Measured results show that the peak efficiency of the converter can reach 93% and sigma-delta modulation suppresses the harmonic spike by 30 dB over PWM modulation.

  6. A low noise high efficiency buck DC-DC converter with sigma-delta modulation

    Energy Technology Data Exchange (ETDEWEB)

    Cai Shujiang; Pi Changming; Yan Wei; Li Wenhong, E-mail: wenhongli@fudan.edu.cn [State Key Laboratory of ASIC and Systems, Fudan University, Shanghai 201203 (China)

    2011-07-15

    Some research efforts to improve the efficiency and noise performance of buck DC-DC converters are explored. A carefully designed power MOSFET driver, including a dead time controller, discontinuous current mode (DCM) controller and gate width controller, is proposed to improve efficiency. Instead of PWM modulation, sigma-delta modulation is introduced into the feedback loop of the converter to move out the clock-referred harmonic spike. The proposed converter has been designed and fabricated by a 0.35 {mu}m CMOS process. Measured results show that the peak efficiency of the converter can reach 93% and sigma-delta modulation suppresses the harmonic spike by 30 dB over PWM modulation. (semiconductor integrated circuits)

  7. Controlled study on the effectiveness of multimedia learning modules for teaching mechanics

    Directory of Open Access Journals (Sweden)

    Homeyra R. Sadaghiani

    2012-02-01

    Full Text Available We have investigated the impact of using multimedia learning modules (MLM on the learning of students enrolled in introductory physics courses at California State Polytechnic University, Pomona. One hundred fifty-nine students were randomly registered in two sections of an introductory mechanics course, one of which featured the MLMs. Both sections had the same instructor, participated in class discussions on identical topics, and used the same problem-solving examples. The students in the multimedia group outperformed the students who did not experience the MLMs in a final course examination and across identical discussion questions.

  8. Hormones in pain modulation and their clinical implications for pain control: a critical review.

    Science.gov (United States)

    Chen, Xueyin; Zhang, Jinyuan; Wang, Xiangrui

    2016-07-01

    Recently, more and more studies have found that pain generation, transmission and modulation are under hormonal regulation. Indeed, hormonal dysregulation is a common component of chronic pain syndromes. Studies have attempted to determine whether the relationship between the pain and its perception and hormones is a causative relationship and how these processes interrelate. This review summarizes and analyzes the current experimental data and provides an overview of the studies addressing these questions. The relationship between pain perception and endocrine effects suggests that hormones can be used as important biomarkers of chronic pain syndromes and/or be developed into therapeutic agents in the fight against pain.

  9. Novel Active Combustion Control Concept for High-Frequency Modulation of Atomized Fuel Flow Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal by Jansen's Aircraft Systems Controls, Inc presents an innovative solution for Active Combustion Control. Relative to the state of the art, this...

  10. Modafinil modulates resting-state functional network connectivity and cognitive control in alcohol-dependent patients

    NARCIS (Netherlands)

    Schmaal, Lianne; Goudriaan, Anna E.; Joos, Leen; Krüse, Anne Maren; Dom, Geert; van den Brink, Wim; Veltman, Dick J.

    2013-01-01

    Chronic alcohol abuse is associated with deficits in cognitive control functions. Cognitive control is likely to be mediated through the interaction between intrinsic large-scale brain networks involved in externally oriented executive functioning and internally focused thought processing. Improving

  11. Modafinil Modulates Resting-State Functional Network Connectivity and Cognitive Control in Alcohol-Dependent Patients

    NARCIS (Netherlands)

    Schmaal, L.; Goudriaan, A.E.; Joos, L.; Kruse, A.M.; Dom, G.; van den Brink, W.; Veltman, D.J.

    2013-01-01

    Background: Chronic alcohol abuse is associated with deficits in cognitive control functions. Cognitive control is likely to be mediated through the interaction between intrinsic large-scale brain networks involved in externally oriented executive functioning and internally focused thought

  12. Control and Modulation Techniques for a Centralized PV Generation System Grid Connected via an Interleaved Inverter

    Directory of Open Access Journals (Sweden)

    Gianluca Brando

    2016-09-01

    Full Text Available In the context of grid connected photovoitaic (PV generation systems, there are two paramount aspects regarding the Maximum Power Point Tracking (MPPT of the photovoltaic units and the continuity of the service. The most diffused MPPT algorithms are based on either perturb and observe, or on an incremental conductance approach and need both PV current and voltage measurements. Several topology reconfigurable converters are also associated with the PV plants, guaranteeing fault-tolerant features. The generation continuity can also be assured by interleaved inverters, which keep the system operating at reduced maximum power in case of failure. In this paper, an evolution of a hysteresis based MPPT algorithm is presented, based on the measurement of only one voltage, together with a novel space vector modulation suitable for a two-channel three-phase grid connected interleaved inverter. The proposed MMPT algorithm and modulation technique are tested by means of several numerical analyses on a PV generation system of about 200 kW maximum power. The results testify the validity of the proposed strategies, showing good performance, even during a fault occurrence and in the presence of deep shading conditions.

  13. The modulation of motor control by imitating non-biological motions: a study about motor resonance.

    Science.gov (United States)

    Miyawaki, Yu; Yamamoto, Taisei

    2018-01-01

    [Purpose] Sensorimotor experience modulates motor resonance, such as motor interference, which occurs when observing others' movements; however, it is unclear how motor resonance is modulated by intentionally imitating others' movements. This study examined the effects of imitation experience on subsequent motor resonance. [Subjects and Methods] Twenty-seven healthy participants performed horizontal arm movements while observing non-biological, incongruent (vertical) movements of a visual stimulus (triangle object) in pre- and post-test procedures. Thirteen participants in the imitation group imitated vertical movements (non-biological motion) of the triangle object between pre- and post-test procedures and fourteen participants in the non-imitation group observed that. [Results] Variance in the executed movements was measured as an index of motor resonance. Although there was no significant difference in the non-imitation group, there was a significantly smaller variance for post-test compared to pre-test in the imitation group. [Conclusion] Motor resonance was inhibited by intentionally imitating non-biological motions. Imitating movements different from one's own motor property might inhibit subsequent motor resonance. This finding might be applied to selectively using motor resonance as a form of rehabilitation.

  14. Generating single photons at gigahertz modulation-speed using electrically controlled quantum dot microlenses

    Energy Technology Data Exchange (ETDEWEB)

    Schlehahn, A.; Schmidt, R.; Hopfmann, C.; Schulze, J.-H.; Strittmatter, A.; Heindel, T., E-mail: tobias.heindel@tu-berlin.de; Reitzenstein, S. [Institut für Festkörperphysik, Technische Universität Berlin, 10623 Berlin (Germany); Gantz, L.; Schmidgall, E. R.; Gershoni, D. [The Physics Department and the Solid State Institute, Technion-Israel Institute of Technology, 32000 Haifa (Israel)

    2016-01-11

    We report on the generation of single-photon pulse trains at a repetition rate of up to 1 GHz. We achieve this speed by modulating the external voltage applied on an electrically contacted quantum dot microlens, which is optically excited by a continuous-wave laser. By modulating the photoluminescence of the quantum dot microlens using a square-wave voltage, single-photon emission is triggered with a response time as short as (281 ± 19) ps, being 6 times faster than the radiative lifetime of (1.75 ± 0.02) ns. This large reduction in the characteristic emission time is enabled by a rapid capacitive gating of emission from the quantum dot, which is placed in the intrinsic region of a p-i-n-junction biased below the onset of electroluminescence. Here, since our circuit acts as a rectifying differentiator, the rising edge of the applied voltage pulses triggers the emission of single photons from the optically excited quantum dot. The non-classical nature of the photon pulse train generated at GHz-speed is proven by intensity autocorrelation measurements with g{sup (2)}(0) = 0.3 ± 0.1. Our results combine optical excitation with fast electrical gating and thus show promise for the generation of indistinguishable single photons at rates exceeding the limitations set by the intrinsic radiative lifetime.

  15. Generating single photons at gigahertz modulation-speed using electrically controlled quantum dot microlenses

    Science.gov (United States)

    Schlehahn, A.; Schmidt, R.; Hopfmann, C.; Schulze, J.-H.; Strittmatter, A.; Heindel, T.; Gantz, L.; Schmidgall, E. R.; Gershoni, D.; Reitzenstein, S.

    2016-01-01

    We report on the generation of single-photon pulse trains at a repetition rate of up to 1 GHz. We achieve this speed by modulating the external voltage applied on an electrically contacted quantum dot microlens, which is optically excited by a continuous-wave laser. By modulating the photoluminescence of the quantum dot microlens using a square-wave voltage, single-photon emission is triggered with a response time as short as (281 ± 19) ps, being 6 times faster than the radiative lifetime of (1.75 ± 0.02) ns. This large reduction in the characteristic emission time is enabled by a rapid capacitive gating of emission from the quantum dot, which is placed in the intrinsic region of a p-i-n-junction biased below the onset of electroluminescence. Here, since our circuit acts as a rectifying differentiator, the rising edge of the applied voltage pulses triggers the emission of single photons from the optically excited quantum dot. The non-classical nature of the photon pulse train generated at GHz-speed is proven by intensity autocorrelation measurements with g(2)(0) = 0.3 ± 0.1. Our results combine optical excitation with fast electrical gating and thus show promise for the generation of indistinguishable single photons at rates exceeding the limitations set by the intrinsic radiative lifetime.

  16. Matrix stiffness modulates formation and activity of neuronal networks of controlled architectures.

    Science.gov (United States)

    Lantoine, Joséphine; Grevesse, Thomas; Villers, Agnès; Delhaye, Geoffrey; Mestdagh, Camille; Versaevel, Marie; Mohammed, Danahe; Bruyère, Céline; Alaimo, Laura; Lacour, Stéphanie P; Ris, Laurence; Gabriele, Sylvain

    2016-05-01

    The ability to construct easily in vitro networks of primary neurons organized with imposed topologies is required for neural tissue engineering as well as for the development of neuronal interfaces with desirable characteristics. However, accumulating evidence suggests that the mechanical properties of the culture matrix can modulate important neuronal functions such as growth, extension, branching and activity. Here we designed robust and reproducible laminin-polylysine grid micropatterns on cell culture substrates that have similar biochemical properties but a 100-fold difference in Young's modulus to investigate the role of the matrix rigidity on the formation and activity of cortical neuronal networks. We found that cell bodies of primary cortical neurons gradually accumulate in circular islands, whereas axonal extensions spread on linear tracks to connect circular islands. Our findings indicate that migration of cortical neurons is enhanced on soft substrates, leading to a faster formation of neuronal networks. Furthermore, the pre-synaptic density was two times higher on stiff substrates and consistently the number of action potentials and miniature synaptic currents was enhanced on stiff substrates. Taken together, our results provide compelling evidence to indicate that matrix stiffness is a key parameter to modulate the growth dynamics, synaptic density and electrophysiological activity of cortical neuronal networks, thus providing useful information on scaffold design for neural tissue engineering. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Neural modulation of muscle-tendon control strategy after a single practice session.

    Science.gov (United States)

    Hirayama, Kuniaki; Yanai, Toshimasa; Kanehisa, Hiroaki; Fukunaga, Tetsuo; Kawakami, Yasuo

    2012-08-01

    The purpose of the present study was to examine a hypothesis that the musculotendinous behavior during a propelling action with a countermovement can be altered by a single practice session through modulation of neuromuscular activities. Eight males performed unilateral maximal plantarflexion with (CMJ) and without (noCMJ) countermovement before and after a practice consisting of six sets of three repetitions of unilateral CMJ exercises. Measurements included EMG activities of the triceps surae and tibialis anterior muscles and the fascicle behavior of the gastrocnemius by ultrasonography, and impulse was calculated from the force-time data. The change in tendon length was also estimated. The impulse in CMJ increased after the practice, but that in noCMJ did not. After the practice, the magnitude of fascicle lengthening and shortening in CMJ decreased, which was accompanied by an increase in tendon shortening without change in the ankle joint range of motion. The time lag from the onset of reaction force to that of EMG activities of the triceps surae muscles was shortened after the practice. The results support the hypothesis and indicate that, as a neural modulation through a single practice, the muscle-tendon unit behavior during CMJ can be optimized to improve the performance.

  18. Significance of red cell distribution width in the differential diagnosis between neurally mediated syncope and arrhythmic syncope in children.

    Science.gov (United States)

    Zhang, Qingyou; Li, Yaqi; Liao, Ying; Du, Junbao

    2017-05-01

    The aim of the present study was to explore the predictive value of red cell distribution width as a means to differentiate between neurally mediated syncope and arrhythmic syncope in children. Patients were divided into a neurally mediated syncope group (n=72) and an arrhythmic syncope group (n=21) on the basis of clinical history, results of the head-up tilt test, electrocardiography, and 24-hour ambulatory electrocardiography. As controls, we recruited 55 healthy children. Red cell distribution width was determined for children in all groups. A receiver operating characteristic curve was drawn to study the predictive effect of red cell distribution width to differentiate between neurally mediated syncope and arrhythmic syncope. Red cell distribution width was significantly higher in children with neurally mediated syncope than in children with arrhythmic syncope and the control group. A receiver operating characteristic curve on the predictive value of red cell distribution width in differentiating neurally mediated syncope from arrhythmic syncope showed that the area under the curve was 0.841 (95% confidence interval: 0.737-0.945, pred cell distribution width value of 12.8% as the cut-off value yielded a sensitivity of 80.6% and a specificity of 76.2% in discriminating between patients with neurally mediated syncope and arrhythmic syncope. Red cell distribution width value of ⩾12.8% might be a useful adjunct for primary-care physicians to differentiate neurally mediated syncope from arrhythmic syncope in children.

  19. Permeability-controlled optical modulator with Tri-gate metamaterial: control of permeability on InP-based photonic integration platform

    Science.gov (United States)

    Amemiya, Tomohiro; Ishikawa, Atsushi; Kanazawa, Toru; Kang, Joonhyung; Nishiyama, Nobuhiko; Miyamoto, Yasuyuki; Tanaka, Takuo; Arai, Shigehisa

    2015-03-01

    Metamaterials are artificially structured materials that can produce innovative optical functionalities such as negative refractive index, invisibility cloaking, and super-resolution imaging. Combining metamaterials with semiconductors enables us to develop novel optoelectronic devices based on the new concept of operation. Here we report the first experimental demonstration of a permeability-controlled waveguide optical modulator consisting of an InGaAsP/InP Mach-Zehnder interferometer with `tri-gate' metamaterial attached on its arms. The tri-gate metamaterial consists of metal resonator arrays and triple-gate field effect elements. It changes its permeability with a change in the controlling gate voltage, thereby changing the refractive index of the interferometer arm to switch the modulator with an extinction ratio of 6.9 dB at a wavelength of 1.55 μm. The result shows the feasibility of InP-based photonic integrated devices that can produce new functions by controlling their permeability as well as their permittivity.

  20. Tai Chi Chuan and Baduanjin practice modulates functional connectivity of the cognitive control network in older adults.

    Science.gov (United States)

    Tao, Jing; Chen, Xiangli; Egorova, Natalia; Liu, Jiao; Xue, Xiehua; Wang, Qin; Zheng, Guohua; Li, Moyi; Hong, Wenjun; Sun, Sharon; Chen, Lidian; Kong, Jian

    2017-02-07

    Cognitive impairment is one of the most common problem saffecting older adults. In this study, we investigated whether Tai Chi Chuan and Baduanjin practice can modulate mental control functionand the resting state functional connectivity (rsFC) of the cognitive control network in older adults. Participants in the two exercise groups practiced either Tai Chi Chuan or Baduanjin for 12 weeks, and those in the control group received basic health education. Memory tests and fMRI scans were conducted at baseline and at the end of the study. Seed-based (bilateral dorsolateral prefrontal cortex, DLPFC) rsFC analysis was performed. We found that compared to the controls, 1) both Tai Chi Chuan and Baduanjin groups demonstrated significant improvements in mental control function; 2) the Tai Chi Chuan group showed a significant decrease in rsFC between the DLPFC and the left superior frontal gyrus (SFG) and anterior cingulate cortex; and 3) the Baduanjin group showed a significant decrease in rsFC between the DLPFC and the left putamen and insula. Mental control improvement was negatively associated with rsFC DLPFC-putamen changes across all subjects. These findings demonstrate the potential of Tai Chi Chuan and Baduanjin exercises in preventing cognitive decline.

  1. Nightside studies of coherent HF Radar spectral width behaviour

    Directory of Open Access Journals (Sweden)

    E. E. Woodfield

    Full Text Available A previous case study found a relationship between high spectral width measured by the CUTLASS Finland HF radar and elevated electron temperatures observed by the EISCAT and ESR incoherent scatter radars in the post-midnight sector of magnetic local time. This paper expands that work by briefly re-examining that interval and looking in depth at two further case studies. In all three cases a region of high HF spectral width (>200 ms-1 exists poleward of a region of low HF spectral width (<200 ms-1. Each case, however, occurs under quite different geomagnetic conditions. The original case study occurred during an interval with no observed electrojet activity, the second study during a transition from quiet to active conditions with a clear band of ion frictional heating indicating the location of the flow reversal boundary, and the third during an isolated sub-storm. These case studies indicate that the relationship between elevated electron temperature and high HF radar spectral width appears on closed field lines after 03:00 magnetic local time (MLT on the nightside. It is not clear whether the same relationship would hold on open field lines, since our analysis of this relationship is restricted in latitude. We find two important properties of high spectral width data on the nightside. Firstly the high spectral width values occur on both open and closed field lines, and secondly that the power spectra which exhibit high widths are both single-peak and multiple-peak. In general the regions of high spectral width (>200 ms-1 have more multiple-peak spectra than the regions of low spectral widths whilst still maintaining a majority of single-peak spectra. We also find that the region of ion frictional heating is collocated with many multiple-peak HF spectra. Several mechanisms for the generation of high spectral width have been proposed which would produce multiple-peak spectra, these are discussed in relation to

  2. Nightside studies of coherent HF Radar spectral width behaviour

    Directory of Open Access Journals (Sweden)

    E. E. Woodfield

    2002-09-01

    Full Text Available A previous case study found a relationship between high spectral width measured by the CUTLASS Finland HF radar and elevated electron temperatures observed by the EISCAT and ESR incoherent scatter radars in the post-midnight sector of magnetic local time. This paper expands that work by briefly re-examining that interval and looking in depth at two further case studies. In all three cases a region of high HF spectral width (>200 ms-1 exists poleward of a region of low HF spectral width (<200 ms-1. Each case, however, occurs under quite different geomagnetic conditions. The original case study occurred during an interval with no observed electrojet activity, the second study during a transition from quiet to active conditions with a clear band of ion frictional heating indicating the location of the flow reversal boundary, and the third during an isolated sub-storm. These case studies indicate that the relationship between elevated electron temperature and high HF radar spectral width appears on closed field lines after 03:00 magnetic local time (MLT on the nightside. It is not clear whether the same relationship would hold on open field lines, since our analysis of this relationship is restricted in latitude. We find two important properties of high spectral width data on the nightside. Firstly the high spectral width values occur on both open and closed field lines, and secondly that the power spectra which exhibit high widths are both single-peak and multiple-peak. In general the regions of high spectral width (>200 ms-1 have more multiple-peak spectra than the regions of low spectral widths whilst still maintaining a majority of single-peak spectra. We also find that the region of ion frictional heating is collocated with many multiple-peak HF spectra. Several mechanisms for the generation of high spectral width have been proposed which would produce multiple-peak spectra, these are discussed in relation to the data presented here. Since the

  3. Influence of electrical sheet width on dynamic magnetic properties

    CERN Document Server

    Chevalier, T; Cornut, B

    2000-01-01

    Effects of the width of electrical steel sheets on dynamic magnetic properties are investigated by solving diffusion equation on the cross-section of the sheet. Linear and non-linear cases are studied, and are compared with measurement on Epstein frame. For the first one an analytical solution is found, while for the second, a 2D finite element simulation is achieved. The influence of width is highlighted for a width thickness ratio lower than 10. It is shown that the behaviour modification in such cases is conditioned by the excitation signal waveform, amplitude and also frequency.

  4. Design and control of a variable geometry turbofan with an independently modulated third stream

    Science.gov (United States)

    Simmons, Ronald J.

    Emerging 21st century military missions task engines to deliver the fuel efficiency of a high bypass turbofan while retaining the ability to produce the high specific thrust of a low bypass turbofan. This study explores the possibility of satisfying such competing demands by adding a second independently modulated bypass stream to the basic turbofan architecture. This third stream can be used for a variety of purposes including: providing a cool heat sink for dissipating aircraft heat loads, cooling turbine cooling air, and providing a readily available stream of constant pressure ratio air for lift augmentation. Furthermore, by modulating airflow to the second and third streams, it is possible to continuously match the engine's airflow demand to the inlet's airflow supply thereby reducing spillage and increasing propulsive efficiency. This research begins with a historical perspective of variable cycle engines and shows a logical progression to proposed architectures. Then a novel method for investigating optimal performance is presented which determines most favorable on design variable geometry settings, most beneficial moment to terminate flow holding, and an optimal scheduling of variable features for fuel efficient off design operation. Mission analysis conducted across the three candidate missions verifies that these three stream variable cycles can deliver fuel savings in excess of 30% relative to a year 2000 reference turbofan. This research concludes by evaluating the relative impact of each variable technology on the performance of adaptive engine architectures. The most promising technologies include modulated turbine cooling air, variable high pressure turbine inlet area and variable third stream nozzle throat area. With just these few features it is possible to obtain nearly optimal performance, including 90% or more of the potential fuel savings, with far fewer variable features than are available in the study engine. It is abundantly clear that

  5. Modulation of Posterior Alpha Activity by Spatial Attention Allows for Controlling A Continuous Brain-Computer Interface.

    Science.gov (United States)

    Horschig, Jörn M; Oosterheert, Wouter; Oostenveld, Robert; Jensen, Ole

    2015-11-01

    Here we report that the modulation of alpha activity by covert attention can be used as a control signal in an online brain-computer interface, that it is reliable, and that it is robust. Subjects were instructed to orient covert visual attention to the left or right hemifield. We decoded the direction of attention from the magnetoencephalogram by a template matching classifier and provided the classification outcome to the subject in real-time using a novel graphical user interface. Training data for the templates were obtained from a Posner-cueing task conducted just before the BCI task. Eleven subjects participated in four sessions each. Eight of the subjects achieved classification rates significantly above chance level. Subjects were able to significantly increase their performance from the first to the second session. Individual patterns of posterior alpha power remained stable throughout the four sessions and did not change with increased performance. We conclude that posterior alpha power can successfully be used as a control signal in brain-computer interfaces. We also discuss several ideas for further improving the setup and propose future research based on solid hypotheses about behavioral consequences of modulating neuronal oscillations by brain computer interfacing.

  6. Self-balanced modulation and magnetic rebalancing method for parallel multilevel inverters

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hui; Shi, Yanjun

    2017-11-28

    A self-balanced modulation method and a closed-loop magnetic flux rebalancing control method for parallel multilevel inverters. The combination of the two methods provides for balancing of the magnetic flux of the inter-cell transformers (ICTs) of the parallel multilevel inverters without deteriorating the quality of the output voltage. In various embodiments a parallel multi-level inverter modulator is provide including a multi-channel comparator to generate a multiplexed digitized ideal waveform for a parallel multi-level inverter and a finite state machine (FSM) module coupled to the parallel multi-channel comparator, the FSM module to receive the multiplexed digitized ideal waveform and to generate a pulse width modulated gate-drive signal for each switching device of the parallel multi-level inverter. The system and method provides for optimization of the output voltage spectrum without influence the magnetic balancing.

  7. Matlab/Simulink Based Analysis of Voltage Source Inverter With Space Vector Modulation

    Directory of Open Access Journals (Sweden)

    Auzani Jidin

    2009-04-01

    Full Text Available Space vector modulation (SVM is the best modulation technique to drive 3-phase load such as 3-phase induction motor. In this paper, the pulse width modulation strategy with SVM is analyzed in detail. The modulation strategy uses switching time calculator to calculate the timing of voltage vector applied to the three-phase balanced-load. The principle of the space vector modulation strategy is performed using Matlab/Simulink. The simulation result indicates that this algorithm is flexible and suitable to use for advance vector control. The strategy of the switching minimizes the distortion of load current as well as loss due to minimize number of commutations in the inverter.

  8. Planning and control of automated material handling systems: The merge module

    OpenAIRE

    Haneyah, S.W.A.; Johann L. Hurink; Schutten, Johannes M.J.; Zijm, Willem H.M.; Schuur, Peter; Hu, Bo; Morasch, Karl; Pickl, Stefan; Siegle, Markus

    2011-01-01

    We address the field of internal logistics, embodied in Automated Material Handling Systems (AMHSs), which are complex installations employed in sectors such as Baggage Handling, Physical Distribution, and Parcel & Postal. We work on designing an integral planning and real-time control architecture, and a set of generic algorithms for AMHSs. Planning and control of these systems need to be robust, and to yield close-to-optimal system performance. Currently, planning and control of AMHSs is hi...

  9. Kinetic control over pathway complexity in supramolecular polymerization through modulating the energy landscape by rational molecular design.

    Science.gov (United States)

    Ogi, Soichiro; Fukui, Tomoya; Jue, Melinda L; Takeuchi, Masayuki; Sugiyasu, Kazunori

    2014-12-22

    Far-from-equilibrium thermodynamic systems that are established as a consequence of coupled equilibria are the origin of the complex behavior of biological systems. Therefore, research in supramolecular chemistry has recently been shifting emphasis from a thermodynamic standpoint to a kinetic one; however, control over the complex kinetic processes is still in its infancy. Herein, we report our attempt to control the time evolution of supramolecular assembly in a process in which the supramolecular assembly transforms from a J-aggregate to an H-aggregate over time. The transformation proceeds through a delicate interplay of these two aggregation pathways. We have succeeded in modulating the energy landscape of the respective aggregates by a rational molecular design. On the basis of this understanding of the energy landscape, programming of the time evolution was achieved through adjusting the balance between the coupled equilibria. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Control of liver cell fate decision by a gradient of TGF beta signaling modulated by Onecut transcription factors.

    Science.gov (United States)

    Clotman, Frédéric; Jacquemin, Patrick; Plumb-Rudewiez, Nicolas; Pierreux, Christophe E; Van der Smissen, Patrick; Dietz, Harry C; Courtoy, Pierre J; Rousseau, Guy G; Lemaigre, Frédéric P

    2005-08-15

    During liver development, hepatocytes and biliary cells differentiate from common progenitors called hepatoblasts. The factors that control hepatoblast fate decision are unknown. Here we report that a gradient of activin/TGFbeta signaling controls hepatoblast differentiation. High activin/TGFbeta signaling is required near the portal vein for differentiation of biliary cells. The Onecut transcription factors HNF-6 and OC-2 inhibit activin/TGFbeta signaling in the parenchyma, and this allows normal hepatocyte differentiation. In the absence of Onecut factors, the shape of the activin/TGFbeta gradient is perturbed and the hepatoblasts differentiate into hybrid cells that display characteristics of both hepatocytes and biliary cells. Thus, a gradient of activin/TGFbeta signaling modulated by Onecut factors is required to segregate the hepatocytic and the biliary lineages.

  11. Control of liver cell fate decision by a gradient of TGFβ signaling modulated by Onecut transcription factors

    Science.gov (United States)

    Clotman, Frédéric; Jacquemin, Patrick; Plumb-Rudewiez, Nicolas; Pierreux, Christophe E.; Van der Smissen, Patrick; Dietz, Harry C.; Courtoy, Pierre J.; Rousseau, Guy G.; Lemaigre, Frédéric P.

    2005-01-01

    During liver development, hepatocytes and biliary cells differentiate from common progenitors called hepatoblasts. The factors that control hepatoblast fate decision are unknown. Here we report that a gradient of activin/TGFβ signaling controls hepatoblast differentiation. High activin/TGFβ signaling is required near the portal vein for differentiation of biliary cells. The Onecut transcription factors HNF-6 and OC-2 inhibit activin/TGFβ signaling in the parenchyma, and this allows normal hepatocyte differentiation. In the absence of Onecut factors, the shape of the activin/TGFβ gradient is perturbed and the hepatoblasts differentiate into hybrid cells that display characteristics of both hepatocytes and biliary cells. Thus, a gradient of activin/TGFβ signaling modulated by Onecut factors is required to segregate the hepatocytic and the biliary lineages. PMID:16103213

  12. Imaging contrast and tip-sample interaction of non-contact amplitude modulation atomic force microscopy with Q-control

    Science.gov (United States)

    Shi, Shuai; Guo, Dan; Luo, Jianbin

    2017-10-01

    Active quality factor (Q) exhibits many promising properties in dynamic atomic force microscopy. Energy dissipation and image contrasts are investigated in the non-contact amplitude modulation atomic force microscopy (AM-AFM) with an active Q-control circuit in the ambient air environment. Dissipated power and virial were calculated to compare the highly nonlinear interaction of tip-sample and image contrasts with different Q gain values. Greater free amplitudes and lower effective Q values show better contrasts for the same setpoint ratio. Active quality factor also can be employed to change tip-sample interaction force in non-contact regime. It is meaningful that non-destructive and better contrast images can be realized in non-contact AM-AFM by applying an active Q-control to the dynamic system.

  13. Mode control of an X-band phase-locked relativistic backward wave oscillator by modulated electron beam

    Science.gov (United States)

    Wu, Y.; Chen, Y. D.

    2017-10-01

    To achieve mode control of an X-band relativistic backward wave oscillator (RBWO) locked by a modulated electron beam, the mechanism of the parasitic mode oscillation and its influence on the working characteristics of the phase-locked RBWO are explored detailedly both in particle-in-cell simulation and in experiment. The experimental result agrees well with the simulation, which indicates that the TM11's excitation in the cavities and the TE11's coupling between the cavities are the main causes of the parasitic mode self-oscillation. Accordingly, RF lossy material is introduced to sever this coupling and suppress the parasitic mode oscillation. The suppression effect of the lossy material is also tested in the experiment, and the parasitic mode oscillation is eliminated. Finally, mode control of the phase-locked RBWO is accomplished experimentally. The phase jitter maintains at a level of ±10° in 50 ns.

  14. Controllability modulates the anticipatory response in the human ventromedial prefrontal cortex

    Directory of Open Access Journals (Sweden)

    Deborah Lucille Kerr

    2012-12-01

    Full Text Available Research has consistently shown that control is critical to psychological functioning, with perceived lack of control considered to play a crucial role in the manifestation of symptoms in psychiatric disorders. In a model of behavioral control based on nonhuman animal work, Maier and colleagues posited that the presence of control activates areas of the ventromedial prefrontal cortex (vmPFC, which in turn inhibit the normative stress response in the dorsal raphe nucleus and amygdala. To test Maier’s model in humans, we investigated the effects of control over potent aversive stimuli by presenting video clips of snakes to 21 snake phobics who were otherwise healthy with no comorbid psychopathologies. Based on prior research documenting that disrupted neural processing during the anticipation of adverse events can be influenced by different forms of cognitive processing such as perceptions of control, analyses focused on the anticipatory activity preceding the videos. We found that phobics exhibited greater vmPFC activity during the anticipation of snake videos when they had control over whether the videos were presented as compared to when they had no control over the presentation of the videos. In addition, observed functional connectivity between the vmPFC and the amygdala is consistent with previous work documenting vmPFC inhibition of the amygdala. Our results provide evidence to support the extension of Maier’s model of behavioral control to include anticipatory function in humans.

  15. Continuous and discontinuous modulation techniques for multiphase drives: analysis and contributions

    OpenAIRE

    Prieto Corvalán, Joel Diego Marcelino

    2016-01-01

    Falta palabras claves The study of multiphase machines applications is an emergent field of research mainly because of the high reliability they offer for high power applications. Nowadays, they are predominantly supplied from two-level voltage source inverters (VSIs). For the purpose of the inverter control, both carrier-based and space vector pulse width modulation (PWM) techniques have been developed, for various phase numbers, which are capable of generating required sinusoidal output ...

  16. VTA GABA neurons modulate specific learning behaviours through the control of dopamine and cholinergic systems

    Directory of Open Access Journals (Sweden)

    Meaghan C Creed

    2014-01-01

    Full Text Available The mesolimbic reward system is primarily comprised of the ventral tegmental area (VTA and the nucleus accumbens (NAc as well as their afferent and efferent connections. This circuitry is essential for learning about stimuli associated with motivationally-relevant outcomes. Moreover, addictive drugs affect and remodel this system, which may underlie their addictive properties. In addition to DA neurons, the VTA also contains approximately 30% ɣ-aminobutyric acid (GABA neurons. The task of signalling both rewarding and aversive events from the VTA to the NAc has mostly been ascribed to DA neurons and the role of GABA neurons has been largely neglected until recently. GABA neurons provide local inhibition of DA neurons and also long-range inhibition of projection regions, including the NAc. Here we review studies using a combination of in vivo and ex vivo electrophysiology, pharmacogenetic and optogenetic manipulations that have characterized the functional neuroanatomy of inhibitory circuits in the mesolimbic system, and describe how GABA neurons of the VTA regulate reward and aversion-related learning. We also discuss pharmacogenetic manipulation of this system with benzodiazepines (BDZs, a class of addictive drugs, which act directly on GABAA receptors located on GABA neurons of the VTA. The results gathered with each of these approaches suggest that VTA GABA neurons bi-directionally modulate activity of local DA neurons, underlying reward or aversion at the behavioural level. Conversely, long-range GABA projections from the VTA to the NAc selectively target cholinergic interneurons (CINs to pause their firing and temporarily reduce cholinergic tone in the NAc, which modulates associative learning. Further characterization of inhibitory circuit function within and beyond the VTA is needed in order to fully understand the function of the mesolimbic system under normal and pathological conditions.

  17. Dimerization Controls Marburg Virus VP24-dependent Modulation of Host Antioxidative Stress Responses

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Britney; Li, Jing; Adhikari, Jagat; Edwards, Megan R.; Zhang, Hao; Schwarz, Toni; Leung, Daisy W.; Basler, Christopher F.; Gross, Michael L.; Amarasinghe, Gaya K.

    2016-08-04

    Marburg virus (MARV), a member of the Filoviridae family that also includes Ebola virus (EBOV), causes lethal hemorrhagic fever with case fatality rates that have exceeded 50% in some outbreaks. Within an infected cell, there are numerous host-viral interactions that contribute to the outcome of infection. Recent studies identified MARV protein 24 (mVP24) as a modulator of the host antioxidative responses, but the molecular mechanism remains unclear. Using a combination of biochemical and mass spectrometry studies, we show that mVP24 is a dimer in solution that directly binds to the Kelch domain of Kelch-like ECH-associated protein 1 (Keap1) to regulate nuclear factor (erythroid-derived 2)-like 2 (Nrf2). This interaction between Keap1 and mVP24 occurs through the Kelch interaction loop (K-Loop) of mVP24 leading to upregulation of antioxidant response element transcription, which is distinct from other Kelch binders that regulate Nrf2 activity. N-terminal truncations disrupt mVP24 dimerization, allowing monomeric mVP24 to bind Kelch with higher affinity and stimulate higher antioxidative stress response element (ARE) reporter activity. Mass spectrometry-based mapping of the interface revealed overlapping binding sites on Kelch for mVP24 and the Nrf2 proteins. Substitution of conserved cysteines, C209 and C210, to alanine in the mVP24 K-Loop abrogates Kelch binding and ARE activation. Our studies identify a shift in the monomer-dimer equilibrium of MARV VP24, driven by its interaction with Keap1 Kelch domain, as a critical determinant that modulates host responses to pathogenic Marburg viral infections.

  18. Bone morphogenetic protein modulator BMPER is highly expressed in malignant tumors and controls invasive cell behavior.

    Science.gov (United States)

    Heinke, J; Kerber, M; Rahner, S; Mnich, L; Lassmann, S; Helbing, T; Werner, M; Patterson, C; Bode, C; Moser, M

    2012-06-14

    Bone morphogenetic proteins (BMPs) are growth factors that exert important functions in cell proliferation, migration and differentiation. Till date, multiple human tumors have been reported to display a dysregulation of several members of the BMP pathway that is associated with enhanced malignant tumor growth and metastasis. BMPER (BMP endothelial cell precursor-derived regulator) is a direct BMP modulator that is necessary for BMPs to exert their full-range signaling activity. Moreover, BMPER is expressed by endothelial cells and their progenitors, and has pro-angiogenic features in these cells. Here, we describe the expression of BMPER in human specimens of lung, colon and cervix carcinomas and cell lines derived from such carcinomas. In contrast to healthy tissues, BMPER is highly expressed upon malignant deterioration. Functionally, loss of BMPER in the lung tumor cell line A549 impairs proliferation, migration, invasion as well as tumor cell-induced endothelial cell sprout formation. In contrast, stimulation of A549 cells with exogenous BMPER had no further effect. We found that the BMPER effect may be transduced by regulation of the BMP target transcription factor inhibitor of DNA binding 1 (Id1) and matrix metalloproteinases (MMPs) 9 and 2. These facilitators of cell migration are downregulated when BMPER is absent. To prove the relevance of our in vitro results in vivo, we generated Lewis lung carcinoma cells with impaired BMPER expression and implanted them into the lungs of C57BL/6 mice. In this model, the absence of BMPER resulted in severely reduced tumor growth and tumor angiogenesis. Taken together, these data unequivocally demonstrate that the BMP modulator BMPER is highly expressed in malignant tumors and tumor growth is dependent on the presence of BMPER.

  19. Speed Sensorless vector control of parallel-connected three-phase two-motor single-inverter drive system

    DEFF Research Database (Denmark)

    Gunabalan, Ramachandiran; Sanjeevikumar, Padmanaban; Blaabjerg, Frede

    2016-01-01

    This paper presents the characteristic behavior of direct vector control of two induction motors with sensorless speed feedback having the same rating parameters, paralleled combination, and supplied from a single current-controlled pulse-width-modulated voltage-source inverter drive. Natural obs...

  20. 76 FR 78 - Federal Motor Vehicle Safety Standard; Engine Control Module Speed Limiter Device

    Science.gov (United States)

    2011-01-03

    ... posted speed limit of 55 mph that was in effect in 1991. \\2\\ Comercial Motor Vehicle Speed Control... improved truck designs. \\3\\ Comercial Motor Vehicle Speed Control Devices (1991), DOT HS 807 725. TCA... National Highway Traffic Safety Administration 49 CFR Part 571 Federal Motor Vehicle Safety Standard...